sajsm vol. 28 no. 1 2016 1 editorial a new era for the south african journal of sports medicine the south african journal of sports medicine is entering a new phase in its development. the journal started in 1982 and was published in‑house. these early editions of the journal are in the archives (http://journals.assaf.org.za/index.php/sajsm/index). it is worth reading papers published in this era to see how far some of the topics on sports medicine have progressed, and how other areas have remained rather static. reading these papers also gives a glimpse into the development of the south african sports medicine association (sasma) and how it has evolved from being a discipline representing mostly orthopaedic surgeons to a multidisciplinary organisation representing a range of health professionals. the health and media publishing group started publishing the south african journal of sports medicine in 1998. they also published the south african medical journal and 13 other smaller journals all covering topics allied to health and medicine. these publishers provided an excellent service until 2015. business pressures in the publishing world and the need to change their financial model resulted in this journal having to part ways. it was always a pleasure to interact with the staff of this publishing group, who delivered a professional service and contributed to the development of the journal. this relationship enabled us to raise the journal’s standard resulting in it getting accredited by the south african department of higher education and training (dhet). without a publisher the journal found itself at a crossroad and the executive of sasma had to make a decision about the future and sustainability of the journal. this decision‑making time coincided with the academy of science of south africa (assaf) offering to assist journals to have an online presence. there are 396 journal titles published in south africa, of which 329 are accredited by the dhet. it is noteworthy that the institution of the authors of each article published in an accredited journal receives r118 000 from the dhet. one of the goals of assaf is to improve the quality of scholarly journals published in south africa. they also oversee the peer review of south african journals. the peer review of the south african journal of sports medicine is available at http://www.assaf.org.za/ files/2015/05/health‑science‑30.9.2014‑2.pdf (p. 45). the invitation from assaf to assist journals with an online presence could not come have at a better time for this journal and it made the decision to continue with an online version of the journal very easy. transitions are never simple. at the onset it seemed a relatively straightforward task of transferring the archives from the old website to the new website. however, following a period of websites crashing, files getting corrupted in the transfer from the old website to the new website, files getting lost, and an accumulation of papers needing to be reviewed, we started wondering whether we were ever going to make it through to the other side! with much support from assaf, we managed to get some stability to the processes and now feel that we are ready to raise the standard of the journal once again. we are presently still behind on our publishing schedule, but anticipate to have four editions completed by the end of 2016, so that we can start 2017 on schedule and have regular editions from that point onwards. publishing regularly according to a schedule is a high priority because this is a prerequisite for getting the journal recognised by medline. we are working hard to achieve this. at present the journal is listed in the following databases: • ajol • crossref • dhet accredited • doaj • open archives registry • pkp index • sabinet • scielo sa • sherpa/romeo • university of illinois oai‑pmh data provider registry • web of knowledge (wok) we are also trying hard to reduce the time it takes to review a paper. this is an ongoing challenge because the pool of reviewers is getting smaller and it is unfair to use the same reviewer too often. we are in the process of refining the guidelines for authors and will be quite strict about only accepting papers for review if they adhere to the guidelines. this is an attempt to make the reviewers’ task easier. some people are going to be disappointed that there is no longer a paper version of the journal. unfortunately the costs of maintaining a paper journal are too prohibitive. in the current form all the papers are freely downloadable. if anyone particularly wants a printed version of the entire issue, please send me an email to mike.lambert@uct.ac.za. apologies to anyone who has been frustrated by the disorganisation during the transition. we are committed going forward, and have an enthusiastic team who are striving to raise the quality of the journal. mike lambert editor-in-chief s afr j sports med 2016;28(1):1. http://journals.assaf.org.za/index.php/sajsm/index http://www.assaf.org.za/files/2015/05/health-science-30.9.2014-2.pdf http://www.assaf.org.za/files/2015/05/health-science-30.9.2014-2.pdf http://www.ajol.info/index.php/sasma http://www.crossref.org/06members/51depositor.html https://www.google.co.za/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=utf-8#q=%e2%80%a2+dhet+accredited https://doaj.org/toc/2078-516x http://www.openarchives.org/ http://index.pkp.sfu.ca/index.php/about http://reference.sabinet.co.za/sa_epublication/m_sajsm http://www.scielo.org.za/scielo.php?script=sci_serial&pid=1015-5163&lng=en&nrm=iso http://www.sherpa.ac.uk/romeo/search.php http://gita.grainger.uiuc.edu/registry/ http://academyofsciencesa.wikispaces.com/file/view/media+release.pdf mailto:mike.lambert@uct.ac.za sportsmed_june04 the second issue of the south african journal of sports medicine in 2004 coincides with an exciting time of the year for sporting events. this is the time for the comrades marathon, berg river canoe race, tour de france, european cup and wimbledon — all great events with a rich history. the new international rugby season begins for south africa while the athletes from various sporting codes prepare themselves for the olympic games. while this is a busy time of the year for the competitors in the various events, it is also a busy time for the support staff behind the scenes; the sports doctors, physiotherapists, biokineticists, coaches and administrators. of these support staff, the administrators are facing increasing pressure as they are expected to deliver a professional service, often with little financial reimbursement. the days of the ‘blazer brigade’ administrators, to use the term coined by a rugby journalist, are numbered. now the sport administrators are expected to act as facilitators, who plan and strategise to increase the level of sporting performance, while also devoting energy and resources to increasing mass participation in their sport. while the administrators of some sporting codes are achieving success, other administrators are clearly dragging their feet, enjoying the cocktail parties and high-profile functions while the sport they have been given the responsibility to manage slips and slides towards mediocrity. perhaps it is quite timely that the sport and recreation distributing agency (srda) of the national lottery board has asked the south african sports commission to facilitate a process to formulate relationships between the srda, tertiary institutions and priority sports federations with the goal of assisting these federations with the development of their respective codes of sport. this process is underway. the next step requires the federations to prepare a 4-year plan which they can submit for funding to the srda. the areas with the potential to be covered by this funding are: • scientific and medical support, including biomechanics • sports technology • life skills • athlete career and education • team preparation and training camps • equipment requirements (sports specific and sports science equipment) • coaching • education and training, including the development of unit standards (coaches, administrators and technical officials) • information management, including database development • modified sport programmes • addressing access and equity issues, including transformation and inclusion of the disabled • sports management, including the development of succession plans for the nfs • facility management • talent identification • research • infrastructure (from club to national level) • high performance plans. plans are also underway for professional consultants to assist the federations so that the 4-year plan has clear objectives with accountabilities for the administrators. if this process is managed properly it may prove to be the elusive light at the end of the tunnel that signals an improvement in the management of our sport. this issue of the journal contains a range of interesting topics. the paper (van der merwe and grobbelaar), showing that over-the-counter nutritional supplements may be contaminated and cause a positive drug test, is cause for alarm. this paper is important from two perspectives: (i) athletes need to show more responsibility when using nutritional supplements as the risk of a positive drug test associated with these supplements is real; and (ii) manufacturers of supplements need to bear some of the responsibility of proving to the consumer that their product is free of contaminated substances and they also need to be accountable should an athlete test positive for a banned substance while using their product. shelly meltzer, dietician and board member of the institute of drug free sport comments on this study and provides further information on the use of nutritional supplements in sport. the next study, by st clair gibson and colleagues, raises the question of ‘accelerated ageing’ in muscles associated with repetitive weight-bearing exercise and poses some interesting questions for future research studies. research into exercise immunology is the fastest growing branch of exercise science. this branch of research is also alive and well in south africa, with a series of papers from tshwane university of technology in pretoria and stellenbosch university. next there is a two-part paper on dietary macronutrient recommendations for optimal recovery after exercise. this comprehensive review contains 135 references on studies that have investigated various aspects of nutritional intervention and recovery after exercise and offers some practical, evidenced-based guidelines for practitioners and athletes alike. i trust that you will enjoy reading this issue! mike lambert editor-in-chief sports medicine vol 16 no.2 2004 1 editorial administration in sport — a much needed kick-start? obituary 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license dr clive noble – a tribute on the 14 january 2022, south africa lost one its great sports medicine pioneers and medical characters. dr clive noble was born in johannesburg in 1938. in his youth he was more of an avid sportsman than an academic. he was a keen rugby player, school shot-put and discus champion, black belt in judo and boxed for the germiston junior team. his academic progress was less stellar, somewhat frustrating his nursing sister mother’s ambitions of young clive becoming a medical doctor. his 4 d’s, an e and an ff in matric were, unsurprisingly, not adequate for acceptance into wits medical school! a determination to succeed determination prevailed however, and clive was eventually accepted to wits and had found his niche! he eventually graduated third in his class and was invited to become the professorial houseman, a great honour then. all the while, clive continued his participation in sport. at wits he took up weightlifting and became south african universities’ and southern transvaal champion. this keen interest in sport and personal experience of the body’s physical capabilities developed a curiosity in injuries associated with sport. a growing interest in sports injuries clive decided that the best fit for him was to specialise in orthopaedic surgery. sports medicine was decades away from becoming a recognised field. clive was meticulous in documenting the results of his operations. the outcomes would be written up and presented in the talks he became renowned for in south africa and abroad. soon after starting his orthopaedic practice in johannesburg, clive noble’s reputation as “the sports injury expert’ was well established and he became the “go-to” doctor for any matter associated with sport and exercise. in fact, anyone who had any injury often sought dr noble’s expertise including rock star rod stewart! his ideas were later formalised into the “pfizer manual of sports injuries”, one of the first sports injuries books. sport teams his contribution to supporting south african sport was immense. he consulted to the boxing board of control from 1963 – 1988. he chaired the transvaal rugby medical committee, served on the south african rugby medical committee and supported touring teams including the british lions and the all blacks. kaizer chiefs and mamelodi sundowns were two of the football teams that made use if his expertise. in 1992 clive was the medical officer for the south african olympic team on our readmission to international sport. during this era, if there was any question regarding an injured sportsperson, dr clive noble would be the first person to call. knowledge translation clive was a great speaker. long before the era of powerpoint, he would scribble a few notes on paper and hold audiences here and abroad keenly attentive as he shared his experiences and theories related to the management of sports injuries. clive was invited to speak across the world where he carried the south african flag high speaking at orthopaedic and sports medicine meetings. sasma and sajsm are born clive, together with a few orthopaedic colleagues, recognised the need to develop a more formal sports medicine structure. in 1985, together with fellow orthopaedist dr ponky firer, radiologist dr louis sirken and a young sports scientist called tim noakes, they formed the south african sports medicine association (sasma) and clive was voted the first president. sasma hosted its first congress which was very well attended. the international network he had established allowed sasma to invite prominent international speakers such as british orthopaedic surgeon dr john williams, dr wolfgang pfoerringer, president of the german society for orthopaedic sports medicine and paediatric orthopaedist dr lyle micheli from boston. simultaneously clive became the first editor of the south african journal of sports medicine, a position he held for 10 years. south africa’s first private sports medicine clinic clive’s travels made him aware of the need for multidisciplinary centres in south africa that housed the expertise for managing sports injuries. for many years he had a dream of such a centre in south africa and this was realised in 1995 when he opened the centre for sports medicine in johannesburg with fellow orthopaedists, a sports medicine physician, radiologist, physiotherapists, biokineticist and dietician. this model became the template for similar centres countrywide. an incredible human being despite having such an aura about him, clive noble had an ability to translate his profound knowledge so that it became easily understandable to junior clinicians as well as his patients. as rudyard kipling wrote, clive could certainly "walk with obituary sajsm vol. 34 no. 1 2022 2 kings but not lose the common touch." a challenging patient would benefit from dr noble popping his head into a colleague’s consultation room for some sage advice, theatre time was spent learning (and sharing plenty of gags!) and afterhours he was always willing to provide telephonic advice. clive was a great character. as much as he was serious in his approach to his patients, he also could appreciate a practical joke. he was a great raconteur and would regale audiences as he wittily reminisced about his experiences in medicine and life. he remained fit throughout his working life. clive competed the comrades marathon and legend has it that his training consisted only of regular calf raises! at the centre in rosebank he would show up younger colleagues and the sportsmen being treated as he marched into the gym, rolled up his sleeves, set the chest press machine at maximum and performed a few repetitions. a legacy in recognition of his pioneering contribution to south african sports medicine, the opening keynote address at the biennial sasma congress is fittingly named “the noble lecture”. but, for those of us lucky to have interacted, worked with and be trained by clive noble, his greatest legacy will be the transfer of incredible knowledge and skills from a generous, gregarious and humble human being with a passion for sports medicine. he shared with us a full and incredible life. jon patricios professor of sport and exercise medicine, wits sport and health, school of therapeutic science, faculty of health science, university of witwatersrand s afr j sports med 2022;34:1-2. doi: 10.17159/2078-516x/2022/v34i1a13095 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13095 https://orcid.org/0000-0002-6829-4098 sajsm 595 (commentarty).indd commentary 85 sajsm vol. 28 no. 3 2016 the need for biokineticists in the south african public health care system r w evans, 1 mphil, t smith, 1 ba, p kay, 1 mphil, d mcwade, 1 mphil, n angouras, 1 bsc (hons), r f van aarde, 1 mphil, r arkell, 1mphil, e v lambert, 1 phd, n van der schyff, 2 md 1 division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, cape town, south africa 2 victoria hospital, wynberg, cape town, south africa corresponding author: r w evans (robertevanssa@gmail.com) noncommunicable diseases and physical inactivity one in two south africans are physically inactive[1], a statistic which urgently needs to be addressed and managed to curb the rampant increase in noncommunicable diseases (ncds). ncds are a category of chronic diseases that are not infectious and hence cannot be passed on from one person to another. they typically progress at a slow rate and include conditions such as cardiovascular disease, cancer, chronic respiratory diseases and diabetes mellitus.[2] a south african summit on the prevention and control of noncommunicable diseases was held on the 12-13 september 2011. the summit reached a consensus regarding the need for an intensified national action plan, addressing prevention, early detection, behavioural change and universal treatment of ncds in south africa. this consensus materialised in the form of the strategic plan for prevention and control of noncommunicable diseases 2013-2017. the strategy, developed by the department of health, identified three public health strategies.[3] 1. prevent ncds and promote health and wellness at population, community and individual levels, 2. improve control of ncds through the strengthening and reform of health care systems, 3. monitor ncds and their main risk factors, as well as the conducting of innovative research. physical inactivity is recognised internationally as a significant, independent and modifiable risk factor contributing to the increased prevalence of ncds.[4] joubert[1] identified that, based on the 1998 south african demographic and health survey data, an alarming number of ncds amongst south africans were attributable to physical inactivity.[5] physical inactivity was identified as attributable to 47% of ischemic heart diseases and 20% of patients with diabetes mellitus; 87% of cases of type 2 diabetes were attributable to excess body weight, along with 68% of hypertensive disease. cost-effective approaches to combatting noncommunicable diseases the associated morbidity of health disorders related to inactivity, including health-related quality of life, as well as direct and indirect economic costs, exerts a substantial burden on societies and health systems. in south africa, use of physicians to address physical inactivity has been estimated to cost r11.80 per head. when compared to the r4.50 per head required for worksite interventions, it is evident that the use of physicians is a relatively large expense.[3] the global advocacy for physical activity (gapa) describes seven best investments for physical activity, advocating for the integration of physical activity into the primary health care system to reduce the development of ncds.[6] the recommended approach to implementing a physical activity programme is a combination of brief counselling and links to community-based supports. these recommendations do not exclude the physician or other health care providers from the management of physical activity; rather it emphasises that a multidisciplinary approach is needed to reduce physical inactivity. biokineticists, in conjunction with physicians and other practitioners, such as dietitians, physiotherapists and psychologists, are in the best position to contribute towards reducing physical inactivity. many biokinetics students are denied internship positions due to a lack of capacity within the private health care sector. the utilisation of both interns and qualified biokineticists in the public health care sector provides a cost-effective approach to combatting an increasingly sedentary south african lifestyle. biokinetics in the south african public health care sector lee[7] demonstrated that a decrease in physical inactivity by 10% will result in excess of 533 000 lives saved due to ncds around the world every year. despite these statistics, south africa is without a health care professional within the primary health care setting that is adequately equipped to develop and implement physical activity programmes. the primary function of a biokineticist is to improve physical functioning and health background: noncommunicable diseases (ncds) are increasingly prevalent within south africa. physical inactivity is a significant, independent and modifiable risk factor increasing the prevalence of ncds. discussion: the integration of physical activity programmes into the primary health care system through multidisciplinary platforms is thus advocated for and envisioned to be more costeffective than current practices. however, currently within the primary health care setting of south africa, there is an absence of health care professionals adequately equipped to develop and implement physical activity programmes. biokineticists, whose scope of practice is to improve physical functioning and health through exercise as a modality, are ideally suited to developing and implementing physical activity programmes in the public sector. yet despite their evident demand, the role of the biokineticist is not incorporated into the national public health care system. conclusion: this short report calls firstly, for the inclusion of biokinetics into the public health care sector, and secondly, for the funding of multidisciplinary community health programmes supporting education, healthy eating and physical activity levels. keywords: noncommunicable disease, physical activity, community health programme, primary health care s afr j sports med 2016;28(3):85-86.doi: 10.17159/2078-516x/2016/v28i3a1310 mailto:robertevanssa@gmail.com http://dx.doi.org/10.17159/2078-516x/2016/v28i3a1310 commentary sajsm vol. 28 no. 3 2016 86 through exercise as a modality. it would thus appear that a biokineticist is ideally suited to developing and implementing programmes to reduce physical inactivity in the public sector. it is evident that based on the biokineticist’s scope of practice; there is an overwhelming demand for their skills in combatting the current burden of ncds facing the country. the demand for biokineticists is evident within the private health care sector as demonstrated by moss and lubbe. [8] however, the vast majority of people (40 million people) cannot afford the expense of private health care. they are therefore reliant on a public health care system already crippled by a quadruple burden of disease of hiv/aids and tuberculosis (tb), high maternal and child mortality, high levels of violence and injuries, and a growing burden of ncds. conclusion and recommendations south africa is without a focused approach to reducing physical inactivity. the south african public health care sector needs to progress beyond treating ncds and adopt strategies focused on prevention. health promotion using physical activity falls directly within the biokineticist’s scope of practice.[9] this short report calls for the support and funding of community-based physical activity interventions in combatting ncds. the time has come for south african policymakers to act upon the strategic plan for prevention and control of ncds 2013-2017. these actions should be the inclusion of biokinetics into the public health care sector and the funding of multidisciplinary community health programmes supporting education, healthy eating and physical activity levels. references 1. joubert j, norman r, lambert ev, et al. estimating the burden of disease attributable to physical inactivity in south africa in 2000. s afr med j 2007; 97(8 pt 2):725-731. pmid: 17952230 2. american college of sports medicine. acsm's guidelines for exercise testing and prescription. 9th ed. lippincott williams & wilkins; 2013. doi:10.1249/jsr.0b013e31829a68cf 3. south africa. department of health. strategic plan for the prevention and control of non-communicable diseases 2013-17. department of health; 2013. available from: http://www.hsrc.ac.za/uploads/pagecontent/3893/ncds%20strat%20p lan%20%20content%208%20april%20proof.pdf 4. steyn k, fourie j, temple n (eds). chronic diseases of lifestyle in south africa: 1995–2005. technical report. cape town: south african medical research council, may 2006:33-47. available from: http://www.mrc.ac.za/noncomm/cdl1995-2005.pdf 5. south africa. department of health. south africa demographic and health survey 1998. department of health, 1998. available from:http://www.mrc.ac.za/bod/sadhs1998fullreport.pdf 6. global advocacy for physical activity (gapa) the advocacy council of the international society for physical activity and health (ispah). ncd prevention: investments that work for physical activity. february 2011. available from: http://www.globalpa.org.uk/pdf/investments-work.pdf 7. lee im, shiroma ej, lobelo f, et al. effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy. lancet 2012 jul 27;380(9838):219-229.doi: 10.1016/s0140-6736(12)61031-9; pmid: 22818936 8. moss sj, lubbe ms. the potential market demand for biokinetics in the private health care sector of south africa. s afr j sports med 2011;23(1):1419. 9. health professions council of south africa (hpcsa). medical, dental and supplementary health service professions act (act no. 56 of 1974), section 33 (1), c1974 [cited 2016 may 18]. available from: http://www.hpcsa.co.za/uploads/editor/userfiles/downloads/rules_reg_c onstitution/regulations_defining_the_scope_of_the_profession_of_biokine tics.pdf http://www.hsrc.ac.za/uploads/pagecontent/3893/ncds%20strat%20plan%20%20content%208%20april%20proof.pdf http://www.hsrc.ac.za/uploads/pagecontent/3893/ncds%20strat%20plan%20%20content%208%20april%20proof.pdf http://www.mrc.ac.za/noncomm/cdl1995-2005.pdf sajsm 595 (commentarty).indd commentary 59 sajsm vol. 28 no. 2 2016 enabling disabled participation in sport: roadrunning d maralack, phd school of management studies, university of cape town, south africa corresponding author: d maralack (david.maralack@uct.ac.za) in march and may 2016, the old mutual two oceans marathon (omtom) and comrades marathon were challenged by wheelchair participants to enter their ultramarathon races. the ultramarathons are physically challenging, pushing athletes to their limits over 56 km and 90 km respectively, over mountainous terrain, exacerbating the physical challenge of the distance. initially both events declined entry to two wheelchair participants based on procedural, logistical and safety grounds, prompting vitriolic discussions on the social media. contestation developed around the ways in which disabled sport participants are integrated (or not) into sporting events with the management, logistics and operational challenges that confront event organisers. this commentary focuses briefly on what can be considered as two sides of the same coin: the rights of disabled and particularly wheelchair participants to be included in ultramarathons in south africa; and the management and regulatory responsibilities of the event organisers in these complex mass participation events. contestations in the social media, proponents argued that it is the constitutional right for differently abled athletes to be permitted to participate in any event. event organisers were branded as “anti-disabled”, “lazy” and “intransigent”. this strand of argument predominated, although some commentators argued that an ultramarathon was not appropriate as “it is too hard” and “physically too challenging”. in clarifying the issues it is important to examine the rights and responsibilities of differently abled participants, as well as those of the event/race organisers. race organisers are required to work within a human rights culture and simultaneously comply with a myriad of safety, health and environmental procedures and regulations. benchmarking the issues while south africa still grapples with managing the incorporation of disabled athletes into mainstream events, other countries have well developed policies and procedures. in this commentary there is a brief reflection on policies of england athletics (ea) and road runners club of america (rrca) on disabled athletic participation, as well as the key policy, health, safety, procedural and monitoring considerations that need to be taken into account in south african roadrunning. the ea and rrca have well developed disabled inclusion policies and processes. an important starting point for both is their focus on facilitating participation by athletes with disabilities. the ea inclusion policy1 argues that disabled people participate in athletic events for the same reason as all athletes for enjoyment, to improve fitness, and to experience the challenge and achievement of competition. as the governing body, ea enhances the knowledge and confidence of event organisers in promoting the inclusion of disabled athletes in events, fosters a change in attitudes, and improves opportunities for disabled athletes to participate. this occurs while safeguarding the safety of all athletes. similarly, the rrca2 argue that while participant safety in a running event remains the paramount concern of any event organiser, clear guidelines will help event organisers focus on real safety concerns related to a specific disability and “not concerns based on false perceptions, stereotypes or generalizations about athletes with disabilities”. hence, the rrca’s policy guidelines assist race organisers to deal with the complex questions surrounding disabled athlete participation in general, including those in wheelchairs. they stress that the guidelines are not intended to cover all events or situations, but rather to foster discussions among event directors, members of the disabled community, law enforcement, public safety personnel and others involved with a particular event. the governing bodies of the ea and rrca respectively predicate entry for disabled athletes on an accommodation request based on, for example, the policy on americans with disability act,2 which includes: a request for accommodation for a specific event which needs to be made to a race organiser a minimum of four to six weeks prior to an event. also, event organisers are encouraged to have a space on their entry forms requesting whether disability accommodation is needed, and informing athletes that it takes four to six weeks after receipt of all medical documents to evaluate such a request. it remains the responsibility of the applicant to contact the race director to ensure compliance with event requirements. they highlight that operationally it may not be reasonable to make an adjustment for disabled athletes; however, it is the race organiser’s responsibility to ensure that they have taken all reasonable steps to consider and implement any the old mutual two oceans marathon (omtom) and comrades marathon were challenged by wheelchair participants to enter their ultramarathon races in 2016, despite the ultramarathon being physically challenging over 56 km and 90 km respectively. the terrain for both is mountainous, exacerbating the physical challenge of the distance. initially both events declined entry to two wheelchair participants, based on procedural, logistical and safety grounds, prompting social media protests and debate. this commentary focuses in brief on the two sides of the same coin: the rights of disabled and specifically wheelchair athletes to be included in ultramarathons in south africa; and the management and regulatory responsibilities of event organisers in these complex events. keywords: running events; mass participation; inclusion; wheelchair; two oceans marathon s afr j sports med 2016;28(2):59-60.doi: 10.17159/2078-516x/2016/v28i2a1429 mailto:david.maralack@uct.ac.za http://dx.doi.org/10.17159/2078-516x/2016/v28i2a1429 commentary sajsm vol. 28 no. 2 2016 60 reasonable adjustments that could be made. south africa these are useful considerations for enabling differently abled participation in roadrunning in south africa. the south african national sport and recreation plan (nsrp)3 emphasises inclusion, directing all sports organisations to develop clear and consistent processes for the inclusion of all participants. at present, policies do promote participation by disabled (including wheelchair) participation in road races, but the guidelines for implementation and accommodation are left to the event organisers. similar to usa track & field (usatf) and ea above, in south africa participant rights have to be balanced with requirements contained in the “safety at sports and recreational events act” (sasrea)4. sasrea sets minimum safety and security standards to safeguard the well-being of all persons at events; holds event role players to account and regulates safety certificates and public liability at events. the act requires that event organisers have approved safety and security measures in place and that its implementation is managed by appropriately experienced people. translating the requirements of sasrea in south africa, road races have to specifically consider how to deal with barriers to participation, and receive prior events planning approval for: (1) traffic and wide bay parking access at the start and finish of the event; (2) appropriate safety logistics at course entry and start position; (3) sufficient course width to accommodate wheelchairs on the route and to consider alternatives when space is deemed to be insufficient; (4) special course considerations such as speed humps, steep hills, descents, and to identify mitigation measures; (5) on course access for medical vehicles that can transport wheelchairs; (6) toilet facilities at the start, en route and at the finish that are accessible for wheelchairs. over and above these legal requirements, drivers of traffic and safety vehicles, volunteers and event staff are required to attend special briefings on all processes and mitigation measures that are in place. the old mutual two oceans marathon therefore has to comply with these requirements and some challenges are the congested start, access and egress on the narrow stretches of shared road with cars on fifty per cent of the course, the steep inclines and, in particular, the descents on chapman’s peak and constantia nek. in addition, race organisers are required to ensure that the medical infrastructure and services en route can respond to all demands. this is not as simple as it seems. going forward what is to be done? an important starting point for all stakeholders is to remove barriers to participation of disabled athletes and at the same time ensuring the safety of all runners. in south africa this requires collaboration and joined-up policymaking and implementation between the governing body of athletics south africa (asa), its provincial affiliates, race organisers, disability sport governing bodies, participants and public safety officials. clear national policy guidelines by asa will assist race organisers to deal with the complex questions surrounding disabled athlete participation, including those for wheelchairs. it is important to acknowledge that event owners have legal responsibilities but it is also imperative to provide a welcoming environment, starting with examining ways in which disabled people can participate as opposed to focusing on the barriers to participation. race organisers need to encourage communication in order to ensure application for event approval is made timeously and enable race organisers to comply with safety procedures specific to wheelchairs. inviting key stakeholders such as the western province sport association for physically disabled (wpsapd) in cape town, south africa, to become a stakeholder in decision-making, ensures that experts guide the process, monitor application and provide feedback for improvement. disabled athletes should be encouraged to contact the race organiser and governing body in advance to discuss the needs and requirements to facilitate inclusion. considerations would include requirements stipulated in sasrea, such as access, health, safety, traffic, medical clearance, safety of equipment, so that there is no danger to either the participants or environment. it is acknowledged that in certain instances it may be inappropriate to permit disabled participation, especially if an unreasonable or drastic adjustment is required that will change the nature of the event. if a risk assessment for the event indicates that it may be unsafe for disabled participation, then the risk assessor must be able to show that the decision was based on sufficient knowledge in the area of disability or has consulted with the appropriate disability organisation2. conclusion this debate needs to be engaged with and understood in the broader running community. all athletes are entitled to enter a race under the same risks and to challenge themselves with hard physical effort, in adverse weather and course conditions. however, there is currently no joined-up policy providing clear and consistent processes of inclusion and circumstances for exclusion. notes: 1. usa track and field is the governing body for athletics in usa. the road runners club of america is affiliated to usat&f and aligns with national usat&f policy and regulations. 2. omtom has redesigned their online application form to include an indication of type and degree of disability, public indemnity process and specific timelines for approval. references 1. england athletics. inclusive athletics guidance: a resource to help athletics providers increase participation by disabled people. accessed http://www.englandathletics.org/disability-athletics/resources august 15, 2016. 2. road runners club of america. guidelines to facilitate participation by athletes with disabilities. accessed in http://www.rrca.org/resources/eventdirectors/guidelines-for-safe-events/challenged-athletes, august 15, 2016. 3. sport and recreation south africa. national sport and recreation plan. pretoria: government printers. 2012. 4. sport and recreation south africa. safety at sports and recreational events act, 2009. pretoria: government printers. 2010. http://www.englandathletics.org/disability-athletics/resources http://www.rrca.org/resources/event-directors/guidelines-for-safe-events/challenged-athletes http://www.rrca.org/resources/event-directors/guidelines-for-safe-events/challenged-athletes sajsm vol. 28 no. 1 2016 27 original research case study an elite runner with cerebral palsy: cost of running determines athletic performance lf prins,1 m.s.; pcm wolters,1 m.s.; e casalino,2 phd; d zimmerman,3 m.s.; jj de koning,1 phd; jp porcari,3 phd; c foster,3 phd, facsm 1 vu university – amsterdam, research institute move, netherlands 2 university of rome “foro italico”, italy 3 university of wisconsin-la crosse, usa corresponding author: c foster (cfoster@uwlax.edu) background: running performance is widely understood in terms of the joyner model (vo2max, %vo2max at ventilatory threshold (vt), running economy (often measured as cost of running (cr) as vo2 in ml.kg‑1.km‑1). objective: to test the joyner model by evaluating a runner in whom one element of the joyner model is systematically abnormal. methods: the case of a two‑time paralympian with cerebral palsy (cp), 2nd place in the sydney 2000 paralympic 1500 m (t37) is reported. incremental and steady state treadmill runs as well as simulated competitions were completed. incremental and steady state (50% ppo) cycling with two legs (2l), the non‑affected leg (nl), and the affected leg (al) were also completed. results: his silver medal (2000 sydney og) performance for 1500 m was 269 s (4:29) (77.2% of velocity in contemporary able‑ bodied world record (wr). at the time of study, his vo2max was 64.2 ml.min‑1.kg‑1. his cost of running (cr) (1% grade) was higher, at 257 vs 228, 211 and 188 ml.kg‑1.km‑1 (for acsm norms, elite europeans, elite east africans). during cycling, his vo2max with 2l, nl and al was 3.74, 3.78 and 3.71 l.min‑1, and his gross efficiency (ge) was 18.4, 12.2 and 9.3%, respectively. conclusions: in a former elite runner with cp, there is little evidence of a central oxygen transport limitation. the higher cr (plausibly reflected by the reduced ge of his al) appears to account for much of the difference in performance compared to able‑bodied runners. the results provide both insight into the physiological limitations of runners with cp and support for the joyner model of competitive running performance. keywords: biomechanics, athletic training, exercise performance, exercise physiology s afr j sports med 2016;28(1):27‑29. doi:10.17159/2078‑516x/2016/v28i1a424 running performance is well described by the joyner model which explains performance as a function of vo2max, the %vo2max at lactate/ventilatory threshold and running economy, often expressed at the cost of running (cr) or vo2 (ml.kg‑1.km‑1).[1] there has been general support for this model, over a generation of sports scientists. a novel way of further testing this model is to evaluate runners where one element of the model is systematically different. this paper reports a case study of an elite runner with cerebral palsy (cp). cp is “a disorder of the development of movement and posture, causing activity limitations attributed to non‑progressive disturbances in the developing fetal or infant brain”.[2] cp is classified from the nature of the movement disorder and the anatomical distribution of motor abnormalities or severity. our subject had spastic hemiplegia on the right side of his body, with unilateral involvement or spasms of the muscles including both arm and leg. he began running in his youth, and competed in different distances (800 m, 1500 m, and 5000 m) at two paralympic games (athens 1996, sydney 2000). his best performance was the silver medal in the 1500 m (t37 class) at the sydney 2000 paralympic games. his personal bests (compared to contemporary wr’s in able‑ bodied runners were: (800 m = 132 s (2:13) vs 102.3 s (1:43) = 77.5%wr; 1500 m = 269 s 4:29) vs 207.7 s (3:27.7) = 77.2%wr; 5000 m = 1060 s (17:42) vs 769.6 s (12:49.6) = 72.5%wr). the purpose of this study is to provide insight into two aspects of performance in athletes with cp. first, what are the characteristics of running performance of a runner with cp compared to able‑bodied runners? second, how do persons with cp adapt to pathological conditions to achieve optimal function. these authors believe that this is the first study to report on cr and physical adaptation in an elite runner with cp. methods at the time of the study (2011), the subject was 31 years old. he had participated in the 1996 and 2000 paralympics, and had trained competitively until 2004. although not competitive at the time of the physiological studies, he was still running three times per week for 30‑40 min and cycling for transportation, mostly at intensities below the ventilatory threshold (vt). the study was approved by the university human subjects committee, according to principles of the declaration of helsinki, and the subject provided written informed consent. the tests consisted of three parts: treadmill running, cycle ergometry and race simulations. all tests were performed at the same time of day (18h00‑20h00) during summer. he undertook no intense training for 48 hrs and no training (except cycling for transportation purposes) for 24 hrs before each test. laboratory tests and races were separated by at least 48 hours. the subject performed incremental treadmill running until exhaustion (2.68 m.s‑1 (9.64 km.h‑1) +0.22 m.s‑1 (0.8 km.h‑1) each minute). he also performed steady state treadmill running (5 minute stages with 1 min walking recovery between stages). performed on a different day, the steady state runs began at 2.23 m.s‑1 (8.0 km.h‑1) and increased by 0.22 m.s‑1 (0.8 km.h‑1) until the velocity at blood lactate = 4 mmol.l‑1 was exceeded. all treadmill runs were performed with the treadmill belt at 1% elevation to mimic wind resistance. respiratory gas exchange was measured using open‑circuit spirometry, with a mixing chamber based metabolic system (aei inc, bastrop, tx), and standard calibration procedures. vo2max was accepted as the highest continuous 30 s vo2 observed during the test. the cost of running (cr) was calculated from the interpolated vo2‑velocity relationship at a vo2 = 90% of that at vt. this was done to assure that the cr represented steady state conditions, and to allow comparison to published norms.[3] blood lactate was measured in capillary blood obtained from a fingertip using dry chemistry (lactate plus). mailto:cfoster@uwlax.edu http://dx.doi.org/10.17159/2078-516x/2016/v28i1a424 28 sajsm vol. 28 no. 1 2016 original research 0 50 100 150 200 250 300 study acsm elite european elite east c o st o f r u n n in g (m l.k g . km ) -1 -1 fig. 1c. cost of running, expressed in ml.kg-1.km-1, for the runner with cp in this study (light), in reference to the acsm norms, and norms for elite european runners and elite east african runners (dark)[3] 0 5 10 15 20 25 elite cyclists able bodied 2l nl al g ro ss e � ci en cy (% ) fig. 1d. gross efficiency during cycling at 50% of ppo in elite cyclists (dark), in able-bodied non-athletes (dark), with 2l by the subject with cp, and with the nl and al by the subject with cp (light) 200 220 240 260 280 300 320 1995 2000 2005 2010 2015 year 15 00 m t im e (s ) fig. 1a. seasonal best 1500 m performances (closed circles), with the contemporary wr for reference (dashed line). note that despite officially retiring from competition, the time for the 2011 time trials (open circle) was still in the general range of his silver medal winning paralympic performance. 12 14 16 18 20 22 24 0 500 1000 1500 sp lit t im e (s ) distance (m) sydney 2000 time trial 1 time trial 2 wr fig. 1b. split 100 m times during 1500 m time trials (2011) (296 and 297 s), during the paralympic silver medal race (2000) (269 s), and for the contemporary wr (208 s) for able-bodied runners. of note is that all races had essentially the same pacing pattern (fast-slow-fast). two 1500 m time trials were performed on an outdoor 400 m track, with an experienced pacemaker, to allow comparison of race results between 2000 and 2011. the pacemaker attempted to run the pace that the subject believed that he could sustain. during the run, based on verbal communication between the subject and pacemaker (e.g. too slow, just right, too fast), the pace was regulated every 50‑100 m. during the last 400 m, the subject attempted to pass the pacemaker, as he would in competition. times were recorded every 100 m. because running is an inherently a bilateral activity, and (as in this subject) cp is often a unilateral pathology the authors felt that it was important to assess differences between his affected leg (al) and non‑affected leg (nl). accordingly, he performed incremental exercise using both legs 25 w + 25 w per 60 s) and, separately, with both the non‑affected and affected legs (25 w + 15 w per 60 s, with 90 s on and 30 s off ). additionally, he performed a 10 min ride at steady state (50% peak power output) on the same cycle ergometer (lode excalibur, groningen, nl), both with 2l and separately with the al and nl. results at the time of the study, the subject’s height and weight were 1.75 m and 63.3 kg respectively, which were unchanged from his competitive years. during his peak competitive years, he trained ~4 times weekly, totalling ~40 km per week, including 2‑3 interval training sessions. he stated that if he trained >4 days per week, he tended to become injured. during incremental treadmill running, his vo2max = 64.2 ml.min‑1.kg‑1, his vo2@vt = 52.8 ml.min‑1.kg‑1, his vo2@rct (respiratory compensation threshold) = 60.8 ml.min‑1.kg‑1. his vmax = 4.58 m.s‑1, vvt = 3.58 m.s‑1, vrct = 4.25 m.s‑1, v4mmol = 3.39 m.s‑1 and vvo2max = 4.33 m.s‑1. his gross vo2max was 4,074 ml.min‑1, with vt and rct at 80% and 95% of vo2max. these percentages are high compared to the normal range of endurance athletes, possibly because the vvo2max was limited by the coordination and work capacity of the al. this finding is duplicated in the cycling results. he remarked that during his competitive career, when he was fatigued, the toe of his al tended to drop, occasionally causing him to fall. comparing his silver medal race in 2000 with his 2011 1500 m time trials shows that although he was slower (269 s (4:29) vs 297 s (4:57) and 296 s (4:56)) (figure  1a), the pattern of pacing was virtually the same (figure  1b). his final time in the two 2011 1500 m time trials represented 91.0% and 91.4% of the velocity achieved during his silver medal race. although the time trials were slower than his paralympic race, they were in the general range of races during his late competitive career, which the authors believe provides evidence that the data collected during 2011 is representative of his physiological responses during his peak competitive period in 2000. sajsm vol. 28 no. 1 2016 29 original research during cycling his peak power output (ppo) was 300 w, 105 w and 190 w with 2l, al and nl, respectively. vo2max was 3.74 (2l), 3.78 (al) and 3.71 (nl) l.min‑1. the vo2max with 2l represented 92% of his running vo2max. it was remarkable that during 1l cycling with his al, the pedalling action was very much “whole body”, with a great degree of accessory muscle involvement, whereas with the nl the cycling action looked normal. the higher cr of our subject is presented in figure 1c. the cr, with 1% grade, was 257 ml.kg‑1.km‑1 vs 228 ml.kg‑1.km‑1, 211 ml.kg‑1.km‑1 and 188 ml.kg‑1.km‑1 vs acsm norms, elite europeans and elite east africans, respectively.[3] the ge during cycling is presented in figure 1d, which depicts the range of elite cyclists, able‑bodied individuals, and our subject’s values for 2l, nl and al. ge during 2l steady state cycling at 50% ppo was 18.4% (150 w, vo2 = 2.42 l.min‑1, rer = 0.84) (at the low end of normal), during 1l cycling with nl was 12.2% (95 w, vo2 = 2.27 l.min‑1, rer = 0.90) and during 1l cycling with his al his ge was 9.3% (53 w, vo2 = 1.68 l.min‑1, rer = 0.95). discussion the main finding of this case study was that an elite runner with cp was characterised by increased cr, which seems to define the mechanism of his reduced (compared to able‑bodied runners) performance ability more than other variables in the joyner model of running. this finding was supported by a decrease in ge during cycling in his al. he was able to achieve vo2max even using the al, apparently by extensive use of the accessory musculature to overcome the strength and coordinative deficit in the al. extrapolating the speed‑vo2 relationship observed in the laboratory his best 2011 performance would require a vo2 of 74 ml.min‑1.kg‑1, representing 115% vo2max. assuming that the cr can improve by no more than 8%[4] and that vo2max is unlikely to increase smore than 2% with the addition of high‑intensity interval training[5], the authors estimated that in sydney at the 2000 paralympic games his cr was no lower than 238 ml.kg‑1.km‑1 and his vo2max was no higher than 66 ml.min‑1.kg‑1. on this basis, his paralympic performance of 269 s would have required a vo2 of 79.9 ml.min‑1.kg‑1, or 121% of his estimated vo2max on race day. the percent of vo2max for both 2000 and 2011 performances are within reason for the relative intensity of elite able‑bodied runners. while even his estimated sydney 2000 race day vo2max is not equivalent to the ~75 ml.min‑1.kg‑1 typically seen in elite middle‑distance runners (~85% as good), his best possible cr is high compared to elite able‑ bodied runners (~75% as good). thus both the 2011 time trials and the projected values for his 2000 paralympic performance support the joyner model of running performance, and suggest that the primary difference between this elite runner with cp and elite able‑ bodied runners is dominantly related to an increase in the cr.[1] his ability to adapt and have a very good performance despite the limitations imposed by cp appears attributable to his ability to recruit accessory muscles to overcome the limitations imposed by cp. this compensatory strategy extracts a cost in terms of reduced ge (e.g. increased cr), which is only possible if vo2max is reasonably high. a recent study from the authors’ laboratory[6] in children with cp demonstrated that ppo (‑25%) and wingate po (‑40%) were more depressed than vo2max (‑15%) compared to age matched controls. these data support the concept that limitations in mechanical power production (e.g. increased cr, decreased ge) contribute to the performance deficit in cp. they further suggest that therapeutic strategies with cp should include efforts to increase vo2max so that these patients can have the physiologic capacity to accommodate their neuromuscular deficit. although not directly measured in this study, it is likely that the spasticity in the al influenced the stretch‑ shortening cycle of the al, decreasing the potential contribution of elastic recoil to propulsion. further, chronic spasticity of the al has the potential for reducing muscle blood flow, in much the same way that the extended duty cycle seen in speed skaters contributes to reduced muscle blood flow and vo2max.[7] references 1. joyner mj. modeling: optimal marathon performance on the basis of physiological factors. j appl physiol 1991;71:1496‑1501. pmid: 1757375. 2. bax m, goldstein m, rosenbaum p, et al. proposed definition and classification of cerebral palsy. dev med child neurol 2005;47:571‑576. [http://dx.doi.org/10.1016/j. jpeds.2008.04.013] 3. foster c, lucia a. running economy: the forgotten factor in elite performance. sports med 2007;37:316‑319. [http://dx.doi.org/10.2165/00007256‑200737040‑ 00011] pmid: 17465597. 4. billat vl, flechet b, petit b, et al. interval training at vo2max : effects on aerobic markers and overtraining markers. med sci sports exerc 1999;31:156‑163. [http:// dx.doi.org/10.1097/00005768‑199901000‑00024] pmid: 9927024. 5. daniels jt, yarborough ra, foster c. changes in vo2max and running performance with training. eur j appl physiol occup physiol 1978;39:249‑254. [http://dx.doi. org/10.1007/bf00421448] pmid: 710390. 6. balemans ac, van wely l, de heer sj, et al. maximal aerobic and anaerobic exercise responses in children with cerebral palsy. med sci sports exerc 2013;45:561‑568. [http://dx.doi.org/10.1249/mss.0b013e3182732b2f ] 7. foster c, rundell kw, snyder ac, et al. evidence for restricted muscle blood flow during speed skating. med sci sports exerc 1999;31: 1433‑1440 [http://dx.doi. org/10.1097/00005768‑199910000‑00012] pmid: 10527516. http://dx.doi.org/10.1016/j.jpeds.2008.04.013 http://dx.doi.org/10.1016/j.jpeds.2008.04.013 http://dx.doi.org/10.2165/00007256-200737040-00011 http://dx.doi.org/10.2165/00007256-200737040-00011 http://dx.doi.org/10.1097/00005768-199901000-00024 http://dx.doi.org/10.1097/00005768-199901000-00024 http://dx.doi.org/10.1007/bf00421448 http://dx.doi.org/10.1007/bf00421448 http://dx.doi.org/10.1249/mss.0b013e3182732b2f http://dx.doi.org/10.1097/00005768-199910000-00012 http://dx.doi.org/10.1097/00005768-199910000-00012 _goback case report 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license exercise intervention for post-acute covid-19 syndrome – do fitt-vp principles apply? a case study g torres,1 phd; n rains,2 mbbch, dch; pj gradidge,1 phd; d constantinou1 mbbch, mphil 1 department of exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, south africa 2 n.h.c health centre, northcliff, south africa corresponding author: g torres (georgia.torres@wits.ac.za) long covid is a condition characterised by persistent symptoms and/or delayed or longterm complications beyond four weeks from the onset of sars-cov-2 infection.[1] a systematic review[2] demonstrated that exercise rehabilitation improves such patients' symptoms and quality of life. five randomised control trials (rcts) included in the review were outpatient/home-based interventions. only two were considered high quality, indicating the need for further and more robust investigations of the rehabilitation of covid-19 patients. the consensus on exercise reporting template (cert)[3] was developed to provide a standardised method for the reporting of exercise interventions and lays down a minimum set of 16 key items considered essential to note in replicable exercise programmes. our case study of these exercise interventions demonstrates the application of the cert (by describing the 16 essential items). it highlights the need for research in developing fitt-vp exercise prescription principles for long covid rehabilitation. case report history a 58-year-old male was hospitalised for 14 days in the intensive care ward to manage his severe covid-19 infection. he had been sedentary before the infection. his disease progression included myocardial involvement, leading to the insertion of a single chamber rate limiting pacemaker on day six of hospitalisation. to regain daily physical functionality, he joined an exercise rehabilitation programme 138 days after discharge. the patient was still symptomatic and reported symptoms of shortness of breath, fatigue, headache, anxiousness, and gastrointestinal upsets. he also reported ambulatory dysfunction (muscle weakness and balance difficulties) and used a walking stick. his prescribed medication was salmeterol xinafoate/fluticasone propionate inhaler (250/25) twice daily. pre-intervention measurements a medical history and examination were carried out by a sports physician to determine his status and to screen for his entry into the rehabilitation programme. thereafter a standard protocol was used to collect baseline assessments shown below: anthropometric measures weight (kg) and height (m) were measured using a seca scale and stadiometer (model 220, vogel and halke, germany), respectively. blood pressure rested and seated brachial blood pressure (mmhg) with an average of two were recorded on the dominant arm using an automated blood pressure cuff (fora active plus p30, faracare suisse, switzerland). pulse oximetry pulse oximeter readings were measured in a rested, seated position using the berry pulse oximeter (bm1000e, shanghai berry electronic tech co., ltd). biochemical analysis venous blood samples were collected and analysed at a commercial pathology laboratory for c-reactive protein (crp) (inflammatory marker) and interleukin 6 (il-6) (immune activation marker). lung function test flow volume loop spirometry was performed using a standardised procedure with the computer-based koko pft the lack of standardisation of reporting exercise interventions hampers the development of best practice guidelines for long covid patients. this case study on the effect of an exercise intervention in a long covid patient applied the consensus on exercise reporting template (cert) for reporting interventions. fitt-vp exercise prescription principles for long covid rehabilitation are also suggested. a 58-year-old male, previously hospitalised for 14 days in the ward for the intensive care for the management of severe covid-19 infection, joined an exercise rehabilitation programme. a medical history, anthropometric, biochemical, lung function, blood pressure, cardiorespiratory fitness and strength measures were all assessed before and after the eight week exercise intervention programme. positive changes were found in all lung function test measures. cardiorespiratory fitness, endurance capacity and muscle strength improved. however, the greatest improvements occurred in functional status, fatigue, dyspnoea and the state of depression levels. this case study suggested that in the absence of other instruments, the fittvp principles may be used for long covid patients, and cert for reporting interventions, but these should be further researched. keywords: rehabilitation, recovery, physical therapy, symptom management s afr j sports med 2023; 35:1-4. doi: 10.17159/2078-516x/2023/v35i1a15284 http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15284 https://orcid.org/0009-0000-2909-0861 https://orcid.org/0000-0002-0197-4718 https://orcid.org/0000-0002-3363-7695 https://orcid.org/0000-0001-5225-1184 case report sajsm vol.35 no.1 2023 2 spirometry (koko pft ltd, waltham abbey, essex, uk). cardiorespiratory fitness (crf) a submaximal crf test was performed using a cycle ergometer (wattbike, nothingham, england) (ramp test mode). resting and effort electrocardiograms were recorded (qrs universal ecg, san diego, usa) and capillary blood lactate concentration was measured (accutrend plus, roche, mannheim, germany). the initial workload was 25w, with increments of 20w every three minutes, until functional volitional fatigue was reached. during the test, ratings of perceived exertion, blood lactate, blood pressure and heart rate measures were collected (the last 30 seconds of each workload). vo2 peak was predicted using equations from the friend registry.[4] hand grip dynamometer strength test muscle strength was measured using a hand grip dynamometer (takei kiki kogyo, japan). the best of three trials were recorded for both hands. questionnaires the post-covid-19 functional status scale[5] was administered to assess daily functionality. the fatigue assessment scale was used for fatigue levels and the mrc dyspnea scale was used to assess breathlessness and difficulty in breathing. the hamilton depression rating scale (ham-d) was used to assess levels of depression. exercise intervention the exercise intervention is described using items from the consensus on exercise reporting template (cert).[3] 1. detailed description of the type of exercise equipment a treadmill and stationary exercise bike were used for endurance training. dumbbells, pilates balls, elastic bands, and strength equipment which controlled movement (e.g. leg press machine and pectoral deck machine) were used for resistance training. 2. detailed description of the qualifications, expertise and/or training an exercise physiologist (phd) and two assistants (honours in biokinetics) delivered the exercise intervention. a standard operating procedure document was developed and used for the intervention. 3+4. describe whether exercises were performed individually or in a group; supervised or unsupervised; how they were delivered all exercise sessions were supervised, performed individually and delivered face-to-face, monitored and tracked via the technogym (tg) mywellness mobile application. 5. detailed description of how adherence to exercise was measured and reported all exercise sessions were verified by direct supervision or by heart rate monitoring via polar monitor and captured on the mywellness mobile app. blood pressure, heart rate, rpe, o2 stats and symptoms were monitored by the supervising exercise professional during all exercise sessions. data were recorded on a spreadsheet. adherence was calculated as a percentage, equal to an actual number of exercise minutes completed each week at the appropriate intensity, divided by the total number of minutes prescribed. the adherence for supervised sessions was 85%. 6. detailed description of motivation strategies verbal encouragement and positive reinforcement were applied during sessions. the self-determination theory of behaviour change and the health belief model that highlight self-efficacy, individual autonomy, perceived benefits and the affective value of a goal/action were used as motivation strategies. links between effect (feelings, emotions) and a particular physical activity/movement were highlighted during exercise. 7a+b. a detailed description of the decision rule(s) for determining exercise progression and how the exercise programme progressed exercise progression was informed by and followed the flowchart set out in the british medical journal.[6] progression included small increments based on patient feedback and responses to exercise. 8. detailed description of each exercise to enable replication the exercises were all made available as videos on the tg mywellness mobile application and accessible by a website link (www.technogym.com/za/technogymapp-za/). 9. detailed description of any home programme component in week five, the participant was confident enough to add walking one-two times a week, of 10-20 min each, outside of supervised sessions. 10. describe whether there are any non-exercise components no other components were added to the exercise intervention. however, it was noted that a psychological component was needed and would have been beneficial to help the high levels of participant anxiety. 11. describe the type and number of adverse events that occur during exercise dizziness during some exercise sessions was experienced by the participant in the first four weeks but always subsided quickly (four events). sessions were adjusted for dizzy spells. 12. describe the setting in which the exercises are performed all exercise sessions were performed at the medical exercise facility, department of exercise science and sports medicine, university of the witwatersrand, south africa. 13. detailed description of the exercise intervention see supplement 1: table 3. 14a+b. describe whether the exercises are generic (one size fits all) or tailored and how exercises are tailored to the individual exercises were based on current known exercise prescriptions for patients presenting with long covid and tailored to the individual based on heart rate response, rpe, dyspnoea level, http://www.technogym.com/za/technogym case report 3 sajsm vol. 35 no.1 2023 exercise technique and symptoms. the exercise programme focussed on large muscle group exercises, with a controlled plane of movement (strength equipment), as for a sedentary or beginner resistance training programme. the specific exercises chosen (e.g. bench press machine) were based on available equipment. exercises were chosen to activate similar muscle groups and movement patterns. for example, when free-standing squats caused knee pain, they were replaced with wall squats using a pilates ball. 15. describe the decision rule for determining the starting level the heart rate at the onset of blood lactate accumulation measured during the crf test determined the starting level for endurance exercise. the starting level for the resistance exercises was based on exercise technique. 16a+b. describe how adherence or fidelity is assessed/ measured and the extent to which the intervention was delivered as planned see item 5. results and outcomes data were analysed to compare baseline and post-intervention outcome measures (tables 1 and 2). all the lung function test variables showed positive changes. the improvements in cardiorespiratory fitness and endurance capacity are clearly shown by the changes in vo2 peak and blood lactate threshold. muscle strength and blood inflammatory marker also improved (tables 1 and 2). however, the greatest improvements occurred in functional status, fatigue, dyspnoea and the state of depression levels. body weight and blood pressure measures showed negative changes (latter within normal reference ranges). discussion the greatest effects of exercise intervention in this case study were in cardiorespiratory fitness, self-reported functional status, fatigue, dyspnoea and the state of depression levels. the unexpected increases in resting heart rate and resting systolic and diastolic blood pressures in the sessions may be attributed to autonomic nervous system effects, e.g. a stressful drive on post-intervention testing day compared to preintervention testing day. another possible explanation for the result is that covid infection could still be lingering in the autonomic nervous system.[7] the improvement in the blood inflammatory marker may have been a combined result of the healing process after hospital discharge (i.e. the participant started to exercise 138 days after hospital discharge) and the effect of the exercise programme. table 1. changes in anthropometric, cardiorespiratory and blood parameters after eight weeks of exercise intervention parameter prepost % change absolute change physical activity level (kcal.wk-1) unknown 763 weight (kg) 129 131 +1.4 +1.8 bmi (kg.m-2) 35.0 35.5 +1.4 +0.5 resting heart rate (b.min-1) 73 79 +8.2 +6 resting oxygen saturation level (%) 95 95 systolic blood pressure (mmhg) 120 133 +10.8 +13 diastolic blood pressure (mmhg) 81 89 +9.8 +8 resting ecg normal normal fvc (l.min-1) 3.70 4.02 +8.6 +0.32 fev1/fvc (%) 71 78 +9.8 +7 pefr (l.s-1) 6.23 6.95 +11.6 +0.72 blood crp level (mg.l-1) 25 3 -88 -22 blood il-6 level (pg.ml-1) 1.8 bmi, body mass index; ecg, electrocardiograms; fvc, forced vital capacity; fev1; forced expiratory volume in one second; pefr, peak expiratory flow rate; crp, c-reactive protein; il-6, interleukin 6. table 2. changes in cardiorespiratory (crf) test, strength and qualitative scale parameters, after eight weeks of exercise intervention parameter prepost% change absolute change predicted vo2 peak (ml.kg-1.min-1) 8.9 13.8 + 55.1 +4.9 power at onset of blood lactate accumulation (w) 53 64 + 20 +10.6 maximal power /mass (w.kg-1) 0.67 0.80 + 19.4 +0.13 o2 saturation before crf test (%) 95 94 1.05 -1 o2 saturation after crf test (%) 94 94 hand grip strength (kg) 42 44 +4.8 +2 post covid-19 functional status scale 3* 2* -33.3 -1 fatigue assessment scale 27 (fatigue) 17 (normal) -37 -10 medical research council dyspnea scale 4** 3** -25 -1 the hamilton depression rating scale (ham-d) 26 (very severe depression) 16 (moderate depression) -38.5 -10 * a lower number means a better functional status; ** a lower number denotes less dyspnoea. crf test data are provided in the supplementary table 4. case report sajsm vol.35 no.1 2023 4 fitt-vp principles, specifically for long covid rehabilitation, have not been developed. after using these techniques in various exercise scenarios, we decided to implement the adjustable approach for long covid since there were no other guidelines available. the following fittvp principles are suggested based on the outcomes of the exercise intervention of this case study: frequency 2 supervised sessions and 1 unsupervised, walking session per week. intensity 65-75 % hrpeak, rpe: 6-11 time 7-10 min endurance exercises + 1-4 resistance exercises: 1 set of 4-8 reps walking (home): 610 minutes at rpe of 6-11 type endurance exercises: (treadmill, walking or cycle ergometry) resistance exercises: (including balance) using strength equipment, dumbbells, wellness balls, bands, body weight+ flexibility (2-4 per session) volume cannot be set, needs to be individualised – based on responses of the individual progression endurance exercises: start at 7 minutes, add 1-2 min every week; after 3 weeks increase %hr peak by 5% rpe: week 14: 6-9; week 5-8: 9-11. resistance exercises: start:1 set of 4-8 reps, increase by 2 reps every week and when reached 10 reps, add 1 set every week until 3 sets of 10 reps; + add 1 exercise every 2 weeks further, to standardise reporting in interventions, the cert is suggested. however, these suggestions need to be researched with further explorative study designs, to recommend detailed exercise prescription for long covid rehabilitation. importantly, long covid symptoms vary vastly per individual, as do responses and adaptations to exercise intervention. thus, the principles need to be flexible and adjusted accordingly to the varied patient responses that may be observed/experienced. conclusion a combined endurance and resistance exercise programme had positive effects on cardiorespiratory fitness, functional status, fatigue and depression levels, with no deleterious effects in parameters that did not show improvement. based on this case study, we recommend using fitt-vp principles as a helpful solution for long covid patients until more advanced methods are discovered through additional research. it is also suggested to adopt standardised reporting using cert. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: gt: conception, design, data collection analysis, interpretation of data and writing of paper. pg, nr and dc: critical revision of manuscript content, writing of manuscript and approval of the version to be published. references 1. lopez-leon s, wegman-ostrosky t, perelman c, et al. more than 50 long-term effects of covid-19: a systematic review and meta-analysis. sci rep 2021;11(1):16144. [doi:10.1038/s41598021-95565-8] 2. fugazzaro s, contri a, esseroukh o, et al. rehabilitation interventions for post-acute covid-19 syndrome: a systematic review. int j environ res public health 2022;19(9):5185. [doi:10.3390/ijerph19095185] 3. slade sc, dionne ce, underwood m, et al. consensus on exercise reporting template (cert): modified delphi study. br j sports med 2016;50:1428–1437. [doi.10.1136/bjsports-2016096651] 4. kokkinos p, kaminsky la, arena r, et al. a new generalized cycle ergometry equation for predicting maximal oxygen uptake: the fitness registry and the importance of exercise national database (friend). eur j prev cardiol 2018;25(10):1077–1082. [doi:10.1177/2047487318772667] 5. klok fa, boon gjam, barco s, et al. the post-covid-19 functional status scale: a tool to measure functional status over time after covid-19. eur respir j 2020;56(1):2001494. [doi:10.1183/13993003.01494-2020] 6. salman d, vishnubala d, le feuvre p, et al. returning to physical activity after covid-19. bmj 2021;372. [doi:10.1136/bmj.m4721] 7. dani m, dirksen a, taraborrelli p, et al. autonomic dysfunction in ‘long covid’: rationale, physiology and management strategies. clin med (london) 2021;21(1):e63-e67. [doi:10.7861/clinmed.2020-0896] case report 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license the unexpected evolution of myocardial injury while infected with the coronavirus: a covid-19 case report j t doran, 1,2 msc 1 jean doran biokineticist, letterkenny, derry and strabane, ireland and united kingdom. 2 director at just kinetics preventive health care provider, ireland, united kingdom and south africa corresponding author: j t doran (jean@justkinetics.com) case report ten months into the pandemic, a fifty-year-old female, having received a positive rt-pcr result, continued to follow public health advice and health authority protocols to self-isolate and stay at home. at the time of the infection, the patient experienced mild symptoms such as a sore throat, headache and what felt like a postnasal drip. the subsequent worsening of the symptoms and the onset of tachycardia on day 13 postinfection caused her to become extremely anxious and resulted in her attending the local emergency department at letterkenny university hospital. although the patient had a history of hypertension and osteoarthritis for which she took no medication, she undertook activities of daily living, but did not partake in regular or structured physical exercise. the sudden onset of pleuritic back pain behind the right shoulder blade which persisted centrally, a persistent cough, chest pain, indigestion, severe shortness of breath and an elevated resting heart rate varying between 96 115 bpm resulted in the patient not only attending but also being admitted to the a&e department of the local general hospital, letterkenny university hospital in the republic of ireland. the patient also self-reported the following symptoms: some relief brought on by her administering paracetamol, the back pain was not exacerbated by movement or by deep inspiration, a feeling of her heart racing (observing a resting heart rate of 121 bpm on her fitbit), two nights of indigestion and pain, whilst sleeping sitting up in bed. on initial assessment, the vital signs indicated no immediate emergency distress, with her bp (blood pressure) 136/89 mmhg, temperature 36°c, pulse 103 bpm (beats per minute), rr (respiratory rate) 20 bpm (breaths per minute) and sao2 (saturated oxygen) 95%. the ecg conducted indicated t-wave inversion, after which she was assigned a yellow triage status. the patient was then discharged and referred to cardiology for cardiac investigations without receiving further treatment. it is unclear if the patient was assessed as having pre-existing t wave changes during this assessment. on day 27, the patient was once again admitted to a&e department as the prior symptoms failed to resolve themselves. a more thorough assessment of her medical history revealed the occurrence of sudden cardiac death in the family (father (53), paternal grandfather (54) and a paternal male cousin in his early (50s)). at this time the patient was selfadministering arcoxia, a non-steroidal anti-inflammatory (nsaid) for knee pain. a reviewed assessment of the vital signs revealed slightly higher levels of all the vitals evaluated when compared to the initial visit on day 13, with bp 145/88 mmhg, temperature 36.5°c, pulse 108 bpm, respiratory rate 20 breaths per minute and sao2 97%. the subsequent ecg showed t wave inversion in leads v2, v3, v4, confirming the initial ecg findings obtained at the previous admittance and assessment on day 13. the patient was now assigned to an orange triage category and kept for further monitoring and investigation. the full blood count (fbc) and differential were normal, with essentially normal liver function, normal renal function, with a glomerular filtration rate (gfr) > 90 ml/min/1.73 m2 and creatinine 1.01 mg/dl. however, the fasting lipogram results that were obtained were as follows: total cholesterol 7.4 mmol/l, triglycerides 3.9 mmol/l, highdensity lipoprotein (hdl) 1.35 mmol/l, low-density lipoprotein (ldl) 5.6 mmol/l. the above normal levels were of reasonable concern as these may be associated with an increased risk of atherosclerosis and therefore there is the possibility that the patient could be suffering a heart attack. background: a novel virus breakout in december 2019, with diverse clinical manifestations, initially identified as infecting the respiratory system, has spread rapidly around the world, with adverse effects which have caused acute myocardial injury and chronic damage to the cardiovascular system in some individuals. aim: to present a clinical case with the manifestation of covid-19 suspected to be either a mild case of either myocarditis or pericarditis. this case highlights a relatively atypical presentation of covid-19 and the value of a coordinated approach to the unexpected sequences of patient recovery patterns that may require further specialist referral and intervention. findings: a ribonucleic acid (rna) viral infection was confirmed by a polymerase chain reaction with reverse transcription (rtpcr) and the patient was diagnosed with coronavirus disease 2019 (covid-19). the presenting symptoms failed to resolve and the patient was admitted to the accident and emergency (a&e) department. upon the second visit to the a&e department at 27 days postinfection, an electrocardiograph (ecg) was conducted revealing t wave inversion. implications: a coordinated approach is needed to combat the infection, develop cardiac-protective strategies and direct supportive measures. keywords: electrocardiography, long-haul covid, pericarditis, gastritis s afr j sports med 2022; 34:1-5. doi: 10.17159/2078-516x/2022/v34i1a11110 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a11110 https://orcid.org/0000-0001-9367-8299 case report sajsm vol.34 no.1 2022 2 ongoing inpatient monitoring over the next two weeks revealed that the patient reported palpitations and experienced episodes of intermittent tachycardia, which was revealed to be a normal sinus rhythm according to the ecg tracings. she also had a normal troponin (tni) level < 0.03 ng/ml and a normal chest x-ray (cxr). the patient was then discharged from the a&e department on day 44, without undergoing any further treatment for a diagnosis of epigastric pain of unknown origin. subsequently, it was arranged for her to wear a holter for five days to monitor any cardiac arrhythmias. she was also referred for an oesophagogastroduodenoscopy (ogds) to exclude any git causes. she was advised to lose weight and to stop taking the arcoxia. medications that were prescribed on discharge to help manage her symptoms included proton pump inhibitors. on day 50, an outpatient follow-up ecg was conducted and revealed a normal sinus rhythm with a right axis deviation. this was interpreted as a possible right ventricular hypertrophy and evidence of possible prior lateral infarct (see fig.1b). on day 57, following the administration of the astra zeneca covid-19 vaccine the patient experienced extreme palpations, as well as breathlessness and fatigue. on day 58 further cardiac investigations were carried out as an outpatient and confirmed previous ecg findings, showing a normal sinus rhythm and t wave inversion in leads v2, v3, v4. an echocardiogram showed normal left ventricle size and function with no significant valve disease. the exercise stress test was terminated prematurely after four minutes as her heart rate rapidly accelerated to 160 bpm, with concomitant chest pain and very minor st changes which resolved quickly during recovery. also on day 58, a computed tomography pulmonary angiogram (ctpa) of the lungs showed atelectasis of the lower lungs. there was also the presence of minor atherosclerotic plaque in the left anterior descending artery (lad), which was not considered significant. a resultant recommendation was made to consider non-atherosclerotic causes of chest pain, as well as the ischemic cardiac changes observed on the ecg. additional advice included considering preventive therapy and risk modification for coronary artery disease. on day 77 the patient presented to a cardiac clinic in south africa with palpitations and tachycardia. on examination, her blood pressure was measured at 140/80 mmhg with a resting pulse rate of 90 bpm, a respiration rate of 12 breaths per minute with clear air entry bilaterally, and no evidence of structural lung disease. during this review, the medical history was consistent with previous reports, including a list of medications indicating alternative nsaids for knee pain other than arcoxia as advised. the resting ecg showed a sinus tachycardia of 110 bpm with noted st/t wave depression from v4 v6. this was also noted inferiorly and at this stage, it was unclear if the st/t wave depression was old or new. in addition, a qrs duration of 80 ms and a qrs axis of approximately 70°+ was noted. a subsequent treadmill test determined that a maximum heart rate was rapidly achieved. the total exercise time was 2 minutes and 12 seconds with a maximum heart rate of 160 bpm equating to 94% of maximum heart rate and a target of 4.17 mets. no supraventricular tachycardia or inducible ventricular tachycardia was documented. the patient was generally deconditioned and in addition had mobility limitations due to her right knee problem. a repeat echocardiogram determined the aortic, pulmonary, tricuspid and mitral valves were all within normal limits and without defect or abnormalities. the patient’s presenting clinical features were reported to be not in keeping with postural orthostatic tachycardia syndrome (pots). autoimmune dysfunction was not excluded. it was also suspected that she may be suffering from a mild form of myo-and/or pericarditis. recommendations were made to follow conservative therapy and lifestyle modifications. depending on the response to this therapy, further electrophysiological opinion should be considered and which may also include a holter assessment. further investigations to be considered included a gastroscopy. there is no record of a creatine kinase (ck), a c-reactive protein (crp) or a d-dimer being carried out. therefore the complete but rather broad differential diagnosis included: possible long-haul covid, mild myocarditis, pericarditis, pleuritis and or gastritis. treatment the patient subsequently sought supportive measures and self-medicated with neem powder which she stated helped to alleviate the shortness of breath and fatigue after/within four days. the use of ulsanic syrup (sucralfate) greatly relieved the chest and gastric distress suggesting a possible gastric contribution to her symptoms. the patient has subsequently followed the recommendations of conservative therapy and lifestyle modifications and has received a dietary prescription from a dietician. she also consulted a biokineticist for cardiac rehabilitation and exercise therapy. the patient seems to have recovered well and is fully functional. she has returned to work, started a new job, and taken on more responsibility. discussion virology it is currently thought that covid-19 infection can be associated with myocardial damage.[1] the pathogenesis of covid-19 disease may include invasion of several essential organs which may result in multiple organ failure and a hyperimmune response, such as the now well-described cytokine storms.[1-4] the heart is one of the potentially most critically affected organs and the infection may contribute to myocardial damage. other viral illnesses, such as influenza, have also been associated with myocardial inflammation such as the development of myocarditis as reported by anupama et al.[5] pathophysiology the pathogenesis of myocardial injury in affected patients postinfection remains unclear.[4, 6-7] the current hypothesis is that the pathogen binds itself to a functional receptor and gains entry into the cell using the angiotensin-converting enzyme 2 (ace2) to accomplish this.[8] patients with prevalent case report 3 sajsm vol. 34 no.1 2022 cardiovascular disease and comorbidities seem to be more significantly associated with morbidity.[3] while it is considered that covid-19 causes viral pneumonia with extrapulmonary manifestations, additional possible major complications are thought to include acute myocardial injury, acute myopericarditis, arrhythmia, shock and long-term chronic damage. related studies, such as the study by guistino[4] , suggest that infection may result in cardiac injury via the following proposed mechanisms: cytokine-mediated damage, oxygen supply/demand imbalance, ischemic injury from microvascular thrombi formation and direct invasion by the pathogen of the myocardium. gastroesophageal reflux which is uncontrolled acid reflux or ingestion may also contribute to the risk of developing interstitial pneumonia. in this case, the pathophysiology and mechanism of cardiac injury remains uncertain. electrocardiography the use of electrocardiography may be useful in the early diagnosis of myocardial injury; however, limited details are available on the changes in electrocardiography linked to myocardial injury post-infection. there seems to be consistent evidence of sinus tachycardia and st depression in the anteroseptal leads irrespective of disease severity.[1] ecg changes as observed in this case can be associated with mild infection and may only present with myocardial necrosis markers in 2-4% of patients, according to li et al.[3] the ecg investigation at 77 days post-infection reports an elevated heart rate of 110 bpm, a qrs axis of approximately 70°+ which is a notable change from the ecg on day 50 (fig. 1b) and which may suggest some clinical improvement in reversible electrocardiographic changes or resolving of the conduction disturbance. there seems to be more prominent t wave changes when comparing the first ecg (fig. 1a) to the second fig. 1a. . ecg of the heart (18 months prior to infection) case report sajsm vol.34 no.1 2022 4 (fig. 1b), most evident in lead v4, with some evidence to suggest the presence of a t wave inversion pre-infection in lead v3. the t wave abnormalities that were noted in the anterior leads may be the only evidence of mild myocarditis as all cardiac bloods were normal and the patient had a resting tachycardia. leads 1 and avl appear quite different in the second ecg (fig. 1b) when compared to the first ecg (fig. 1a), suggesting a possible unexplained high lateral conduction disturbance; similarly avr is also altered in comparison. the persistence of sinus tachycardia could be suggestive of many things including the presence of cardiac inflammation and that in some way the heart is still being influenced. conclusion there is limited understanding of the transmission dynamics and spectrum of clinical illness of covid-19. cardiac involvement with various ecg presentations is possible and clinicians should be aware of this possibility. pericardial and myocardial inflammation may prompt symptoms, yet may precede the generation of an observable pericardial effusion. early management and treatment of the causative disease is critical to prevent the spread of the pathogen and to improve the cure/recovery rates. with particular focus on trying to prevent progression to the inflammatory phase of the disease (i.e. cytokine storm). this case highlights an atypical presentation of covid-19 infection with cardiac involvement and non-specific ecg changes that may present pericarditis and/or mild myocarditis or a subtle ischaemic event. healthcare teams need to consider a coordinated approach for these patients to ensure the correct diagnoses of possible sequelae are made timeously and the appropriate management applied. just as important the clinical management in the acute phase is vital, and so is the management of the recovery phase with the emerging understanding of the role various pharmacoand physical therapy may have to play. this patient had various risk factors known to be associated with worsening morbidity following covid-19 infection, including hypertension and relative physical inactivity. a comorbidity of hypertension, physical inactivity, poor lifestyle and ageing also associated with a higher risk for severe covid-19 outcomes. therefore improving lifestyle factors such as physical activity status (with better bmi, blood pressure control, etc) would presumably be of benefit not only for the patient’s recovery but also in the reduction of the risk of severe disease for future fig. 1b. ecg of the heart (day 50) case report 5 sajsm vol. 34 no.1 2022 re-infections with the virus. cardiac-protective strategies preinfection have been shown to include key contributing factors, such as a healthy immune system, mitochondrial health and consistent physical activity that meets physiologically enhancing levels. it is of interest to note that this patient utilised neem powder, a naturopathic medication which she felt helped reduce her symptoms. neem powder, which is extracted from neem leaves as a natural medicine, was administered by the patient as an alternative to allopathic medicine. neem leaves, purported to have antiviral and anti-inflammatory properties, might be used by some as a treatment against viral infection and as a possible prophylaxis pre-infection. but further research is needed to determine if there is a role for it in the management and prevention of covid-19. this case report may help in the future treatment of patients with this unique clinical presentation. further clinical studies are needed to evaluate the exact role of the cardiac-protective strategies as suggested in this case, this patient remains part of an ongoing investigation. conflict of interest and source of funding: the author declares no conflict of interest and no source of funding. acknowledgements: the author would like to acknowledge and thank the patient for access to her medical records and for providing her informed consent and permission to publish the case report and medical information. author contributions: jtd designed the case report, collected the data, analysed and interpreted the data, and wrote the initial draft and final version of the paper. references 1. liaqat a, ali-khan rs, asad m, et al. evaluation of myocardial injury patterns and st changes among critical and non-critical patients with coronavirus-19 disease. sci rep 2021;11(1):4828. [doi:10.1038/s41598-021-84467-4] [pmid: 33649391] 2. park se. epidemiology, virology, and clinical features of severe acute respiratory syndrome coronavirus-2 (sars-cov-2; coronavirus disease-19). clin exp pediatr 2020; 63(4):119–124. [doi:10.3345/cep.2020.00493][pmid: 32252141] 3. li n, zhu l, sun l, et al. the effects of novel coronavirus (sarscov-2) infection on cardiovascular diseases and cardiopulmonary injuries. stem cell res 2021; 51 :102168 [doi:10.1016/j.scr.2021.102168] [pmid: 33485182] 4. giustino g, croft lb, stefanini gg,,et al. characterization of myocardial injury in patients with covid-19. j am coll cardiol 2020; 76(18): 2043–2055. [doi:10.1016/j.jacc.2020.08.069] [pmid: 33121710] 5. anupama bk, debanik c. a review of acute myocardial injury in coronavirus disease 2019. cureus 12(6): e8426. [doi:10.7759/cureus.8426] [pmid: 32642342] 6. nemati r, ganjoo m, jadidi f, et al. electrocardiography in early diagnosis of cardiovascular complications of covid-19; a systematic literature review. arch acad emerg med 2021; 9(1):e10. [doi:10.22037/aaem.v9i1.957][pmid: 33490967] 7. mehraeen e, alinaghi sa, nowroozi a, et al. a systematic review of ecg findings in patients with covid-19. indian heart j 2020; 72(6):500-507.[doi:10.1016/j.ihj.2020.11.007] [pmid: 33357637] sajsm 595 (commentarty).indd position statement 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license recommendations for athletes and covid-19 vaccinations: a south african sports medicine association (sasma) position statement – part 3 l pillay,1,2,3,4 mbchb, msc; j patricios,2 mbbch, mmedsci; dc janse van rensburg,1,5 md, mmed, msc, mbchb; r saggers,2,9 mbbch, fcpaed, mmed; d ramagole,1 mbchb, msc; p viviers,6,7,8 mbbch, mmedsc; c thompson,6,7,8 mbchb, mphil; s hendricks,10,11,12 phd 1 section sports medicine & sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa 2 wits sport and health (wish), faculty of health sciences, university of the witwatersrand, johannesburg, south africa 3 premier soccer league covid-19 chief medical officer, psl, south africa 4 chief medical officer, gauteng lions cricket, south africa 5 medical board member, world netball, manchester, uk 6 campus health service, stellenbosch university, south africa 7 institute of sport and exercise medicine, division of orthopaedic surgery, department of surgical sciences, faculty of medicine and health sciences, stellenbosch university, south africa 8 fifa medical centre of excellence, south africa 9 department of paediatrics and child health, charlotte maxeke johannesburg academic hospital, johannesburg, south africa 10 division of physiological sciences, department of human biology, faculty of health sciences, university of cape town, south africa 11 health through physical activity, lifestyle and sport (hpals) research centre, department of human biology, faculty of health sciences, university of cape town. south africa 12 carnegie applied rugby research (carr) centre, institute for sport physical activity and leisure, leeds beckett university, leeds, england corresponding author: l pillay (drpillay@absamail.co.za) since the classification of covid-19 as a pandemic by the world health organization (who) on march 11 2020,[1] the entire world has been embroiled in dealing with this disease. several countries around the world have experienced surges in infection numbers or “waves” of covid-19 infections. these waves at separate times in different countries made planning travel and events difficult.[2] it necessitated various levels of lockdown around the world, as determined by each country’s governmental responses to covid-19 activity. all levels of sporting activities, from professional to school, have been affected for sustained periods. at the start of the pandemic, to reduce the transmission of covid-19, lockdown meant that sports training and competition had to be cancelled. the primary non-pharmaceutical interventions against the spread of covid-19 infection remain: (1) hand hygiene, (2) respiratory hygiene, (3) mask-wearing, and (4) social and physical distancing (at gatherings in closed and open spaces). many countries have allowed professional sport to return with strict infection-risk mitigating procedures in place, as approved by their respective governments. as our understanding of covid19 transmission advanced, and to reduce any further negative effects, professional sport was gradually re-introduced under highly controlled environments. these environments were termed ‘bio-secure environments’ (bse) or bio-bubbles. bio-secure environments (bse) presently, certain sports in south africa (such as cricket and rugby) are competing within bio-secure environments– commonly referred to as bio-bubbles. bio-bubbles are possible in these sports as they have defined competitions (for example, the initial post-lockdown resumption of the premier soccer league (psl) and the british and irish lions rugby tour)). biobubbles cannot be achieved in a league setting in which teams play over a protracted period of time. other negative aspects of bio-bubbles include the cost involved in hosting these competitions and the mental anxiety for all those involved. [3],[4] as an example, football in south africa completed the 2019/2020 season in a bio-bubble. the psl completed the 2020/2021 season outside of a bse but with strict risk mitigating health protocols in place. vaccinations on 31 december 2020, the world health organisation (who) validated the first covid-19 vaccination – an mrna vaccine that was subsequently approved for emergency use. [5] subsequently, several vaccines are now approved for emergency use in south africa. since then, data have emerged validating the efficacy of vaccinations in decreasing both transmission and covid-19 disease severity.[6] the function of vaccines in the times of covid-19 is to achieve the following: 1. minimise the risk of contracting covid-19. 2. if there is a breakthrough infection, it reduces the illness to mild symptoms and prevents progression to severe disease which may include hospitalisation and ventilatory support (such as high flow nasal cannula oxygen therapy and polymasks). 3. if there is a breakthrough infection, to reduce the length of time of being infective and reducing the spread of the virus. the covid-19 pandemic initially led to the shutdown of all sport at a high cost to both the economy and athlete health. as risk-mitigating protocols evolved and were implemented, the playing of sport returned slowly to normal. the introduction of covid-19 vaccinations enhances the means of protection and risk management for all. this south african sports medicine association position statement provides recommendations for the vaccination of athletes. keywords: covid-19, vaccination, athletes, recommendations, sports s afr j sports med 2021; 33:1-3. doi: 10.17159/2078-516x/2021/v33i1a12557 mailto:drpillay@absamail.co.za http://dx.doi.org/10.17159/2078-516x/2021/v33i1a12557 https://orcid.org/0000-0002-5341-6080 https://orcid.org/0000-0002-8353-3376 https://orcid.org/0000-0001-6593-8049 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0002-3416-6266 https://orcid.org/0000-0003-1058-6992 https://orcid.org/0000-0001-6682-3438 position statement sajsm vol. 33 no. 1 2021 2 covid-19 vaccinations have been shown to significantly protect against poor disease outcomes.[7] apart from the primary aim of protecting athlete health, an important advantage of an athlete-dedicated vaccine programme is the facilitation of domestic and international travel, allowing major tournaments and leagues to recommence without the need for a bio-bubble. being vaccinated may also reduce travel stress. [8] despite this however, challenges remain. all team members (athletes and support staff) should be fully vaccinated. if all team members are vaccinated, the risk of contracting and spreading covid-19 in the team environment and community is significantly reduced. this limits the need for bio-bubbles. certain countries may still require proof of a negative covid 19 polymerase chain reaction (pcr) test to avoid quarantining in that country.[9] vaccination rollout in south africa the south african vaccine rollout programme has been implemented in phases. phase one began on 17 february 2021 and involved healthcare workers as part of the sisonke trial. [10],[11] the south african health products regulatory authority (sahpra) approved the johnson and johnson covid-19 vaccine on 31 march 2021.[12] further vaccines have subsequently been approved by sahpra (pfizer, sinovac) –see table 1. some athletes competing in major international events, such as the olympic games and the british and irish lions rugby tour, were also enrolled in this trial. the targeted rollout approach for the general population was then extended to the sixty years and older age groups first, to limit severe disease and death. thereafter, individuals with chronic comorbid medical conditions (e.g. diabetes and hypertension) received the vaccination. phase two involved essential workers (teachers, police members), and those in congregated settings (for example, religious leaders). the age limit was later expanded to those over 40 years of age. phase three involved targeting the remainder of the population, in order to achieve a national target of 67%. most athletes fell into this latter age group. the nature of professional sport involves training and competing at high-intensity levels. team sports involve not only interaction with team mates, but also the technical, medical and administrative staff. individual sports involve athlete interaction with coaching and medical staff. complying with non-pharmaceutical interventions (proper mask-wearing, hand sanitising and respiratory hygiene) as risk mitigating measures remain vital. vaccination of athletes further enhances protection against contracting the covid-19 virus and should be strongly encouraged. table 1 displays the availability and approval status of vaccinations in south africa. it is important to note that presently sahpra has approved the pfizer and johnson and johnson vaccines which are part of the nationwide rollout. these have been approved for those eighteen years and older. sinovac has been approved for children twelve years and older. others have been approved, but not rolled out in south africa (astra zeneca) and others are in the process of being approved. recommendations for the vaccination of athletes 1. allow flexible training plans for three days postvaccination, as one cannot predict when vaccine-related side effects will occur. common side effects include headaches, myalgia, fatigue, fever and pain at the site of injection which can typically last two to three days. [13],[14] 2. on the day of vaccination, paracetamol (given at one gram three times a day) can be taken to reduce side effects, if these are experienced. 3. if there is a concern regarding allergies and an athlete is prone to severe allergic reactions, it is advisable to visit a vaccination site where medical staff are available to attend to these allergic reactions. [15] 4. exercise may be performed on the day of vaccination but should be limited to low-intensity sessions. avoid mediumto high-intensity exercise for at least three days.[13] 5. should an athlete experience any vaccine-related side effects, then exercise should be avoided until these symptoms resolve. 6. should an athlete experience persistent or worsening vaccine-related side effects continuing for five days postvaccination, then an active covid-19 infection must be excluded with a pcr test. this should be reported to sahpra. the athlete should consult a medical doctor. [16] 7. should an athlete receive the pfizer vaccine, and within 714 days post-vaccination experience fever, lethargy, shortness of breath and chest pain, myocarditis/ pericarditis these symptoms must be considered and the athlete excluded from physical activities (usually with haematological investigations and an electrocardiogram – ecg). it may also warrant a referral to a cardiologist. [17] 8. if an athlete has recently been infected with covid -19, he/she should be vaccinated at least four weeks after de isolation or symptom resolution.[18] table 1. available vaccines and status of approval in south africa by south african health products regulatory authority (sahpra)[13] manufacturer vaccine platform used in south africa vaccines approved by sahpra for use in south africa astrazeneca chadox1 ncov-19 (azd1222/covishield) viral vector no pfizer/biontech bnt-162b2 mrna yes johnson & johnson ad26.cov2.s viral vector yes sinovac coronavac inactivated not as yet applications submitted and awaiting approval from sahpra gamaleya research institute sputnik v *rolling review by saphra no no application for approval in south africa (but have who emergency use listing) sinopharm bbibp-corv inactivated n/a moderna mrna-1273 mrna n/a novavax nvx-cov2373 recombinant protein n/a position statement 3 sajsm vol. 33 no. 1 2021 9. presently, vaccine choice is limited due to sahpra approval and availability. in principle, all vaccines can be used; indeed, any vaccination is better than none. each vaccine’s efficacy and pitfalls should be considered if options are available. 10. as the science evolves, booster vaccinations may become available. this will be determined by the time of the vaccine effect waning and the type of vaccine initially received. there will ongoing and evolving evidence and approvals as more research is undertaken. considerations for special populations youth: sinovac has been recently approved by sahpra for those 12 years and older.[19] pregnancy: vaccinations can be administered to pregnant (at any stage of pregnancy) and lactating mothers. [20] conclusion vaccinating the athletic population is vital for the continuation of team and individual sport in a safe manner. vaccinations reduce the risk of contracting and transmitting covid-19, and allows for events to continue uninterrupted. conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: lp conceptualised, drafted and finalised the manuscript. djvr, dr, jp, ct, pv, rs and sh critically reviewed the drafts. all involved approved the final version prior to submission. references 1. world health organization. who director-general’s opening remarks at the media briefing on covid-19 – 11 march 2020. https://www.who.int/directorgeneral/speeches/detail/who-director-general-s-openingremarks-at-the-media-briefing-on-covid-19---11-march-2020 (accessed 12 september 2021). 2. worldometer. coronavirus worldwide graphs. 2021. https://www.worldometers.info/coronavirus/worldwidegraphs/ (accessed 12 september 2021). 3. supersport. manners & masks – financial realities of cricket bio-bubbles.https://supersport.com/cricket/news/ 200904_manners_masks_financial_realities of cricket in biobubbles. 2020 (accessed 12 september 2021). 4. outlook. paddy upton warns of mental illnesses due to extended stay in bio-bubble. 2021. https://www.outlookindia.com/website/story/sports-newspaddy-upton-warns-of-mental-illnesses-due-to-extendedstay-in-bio-bubble/372602 (accessed 12 september 2021). 5. world health organization. who issues its first emergency use validation for a covid-19 vaccine and emphasizes need for equitable global access. 2020. https://www.who.int/news/item/31-12-2020-who-issues-itsfirst-emergency-use-validation-for-a-covid-19-vaccine-andemphasizes-need-for-equitable-global-access (accessed 12 september 2021). 6. wise j. covid-19: pfizer biontech vaccine reduced cases by 94% in israel, shows peer reviewed study. bmj 2021; 372 :n567. [doi: 10.1136/bmj.n567] [pmid: 33632676]. 7. scobie hm, johnson ag, suthar ab, et al. monitoring incidence of covid-19 cases, hospitalizations, and deaths, by vaccination status 13 u.s. jurisdictions, april 4–july 17, 2021. mmwr morb mortal wkly rep 2021;70(37):1284–1290. [doi: 10.15585/mmwr.mm7037e1] [pmid: 34529637]. 8. pavli a, maltezou hc. covid-19 vaccine passport for safe resumption of travel. j travel med 2021;28(4):taab079. [doi: 10.1093/jtm/taab079] [pmid: 34008004]. 9. south africa. national institute for communicable diseases. covid-19 vaccine rollout strategy faq. 2021. https://www.nicd.ac.za/covid-19-vaccine-rollout-strategyfaq/#:~:text=the%20vaccines%20will%20be%20rolled,and%20pe rsons%20over%2040%2dyears. (accessed 12 september 2021). 10. south african medical research council. sisonke (together) study. 2021. http://sisonkestudy.samrc.ac.za/ (accessed 12 september 2021). 11. south african health product regulatory authority. sahpra update on vaccine approvals. 21 june 2021. https://www.sahpra.org.za/press-releases/sahpra-update-onvaccine-approvals/ (accessed 12 september 2021). 12. south african health product regulatory authority. sahpra registers the covid-19 vaccine janssen. ad26.cov2-s [recombinant] with conditions. 2021. https://www.sahpra.org.za/press-releases/sahpra-registers-thecovid-19-vaccine-janssen/ (accesed 12 september 2021). 13. hull jh, schwellnus mp, pyne db, et al. covid-19 vaccination in athletes: ready, set, go… lancet respir med 2021;9(5):455-456. [https://doi.org/10.1016/s2213-2600(21)00082-5] [pmid: 33556316]. 14. national institute for communicable diseases. covid-19 vaccine side-effects faq. 2021. https://www.nicd.ac.za/covid19-vaccine-side-effects-faq/ (accessed 12 september 2021). 15. peter j. covid-19 vaccination: recommendations for management of patients with allergy or immune-based diseases. s afr med j 2021;111(4):291-294. [doi: 10.7196/samj.2021.v111i4.15576] [pmid: 33944757]. 16. national institute for communicable diseases. covid-19 vaccination: reporting adverse effects faq. 2021. https://www.nicd.ac.za/covid-19-vaccination-reportingadverse-effects-faq/ (accessed 12 september) 17. world health organization. covid-19 subcommittee of the who global advisory committee on vaccine safety (gacvs) reviews cases of mild myocarditis reported with covid-19 mrna vaccines. 2021. https://www.who.int/news/item/09-072021-gacvs-guidance-myocarditis -reported with covid-19mrna-vaccines (accessed 12 september 2021) 18. sa coronavirus. ministerial advisory committee on covid-19 vaccines. (vmac). 2021. https://sacoronavirus.co.za/2021/06/24/ministerial-advisorycommittee-on-covid-19-vaccines-vmac/ (accessed 12 september). 19. south african health product regulatory authority. sahpra authorises the coronavac vaccine with conditions. 2021. https://www.sahpra.org.za/press-releases/sahpra-authorisesthe-coronavac-vaccine-with-conditions/ (accessed 12 september 2021). 20. national institute for communicable diseases. vaccination of pregnant and breast feeding women (august update). 2021. https://www.nicd.ac.za/vaccination-of-pregnant-andbreastfeeding-women-august-update/ (accessed 12 september 2021) https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020 https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020 https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020 https://www.worldometers.info/coronavirus/worldwide-graphs/ https://www.worldometers.info/coronavirus/worldwide-graphs/ https://supersport.com/cricket/news/%20200904_manners_masks_financial_realities%20of%20cricket%20in%20biobubbles https://supersport.com/cricket/news/%20200904_manners_masks_financial_realities%20of%20cricket%20in%20biobubbles https://supersport.com/cricket/news/%20200904_manners_masks_financial_realities%20of%20cricket%20in%20biobubbles https://www.outlookindia.com/website/story/sports-news-paddy-upton-warns-of-mental-illnesses-due-to-extended-stay-in-bio-bubble/372602 https://www.outlookindia.com/website/story/sports-news-paddy-upton-warns-of-mental-illnesses-due-to-extended-stay-in-bio-bubble/372602 https://www.outlookindia.com/website/story/sports-news-paddy-upton-warns-of-mental-illnesses-due-to-extended-stay-in-bio-bubble/372602 https://www.who.int/news/item/31-12-2020-who-issues-its-first-emergency-usehttps://www.who.int/news/item/31-12-2020-who-issues-its-first-emergency-usehttps://www.who.int/news/item/31-12-2020-who-issues-its-first-emergency-usedoi:%2010.1136/bmj.n567 doi:%2010.15585/mmwr.mm7037e1 doi:%2010.15585/mmwr.mm7037e1 doi:%2010.1093/jtm/taab079 doi:%2010.1093/jtm/taab079 https://www.nicd.ac.za/covid-19-vaccine-rollout-strategy-faq/#:~:text=the%20vaccines%20will%20be%20rolled,and%20persons%20over%2040%2dyears. https://www.nicd.ac.za/covid-19-vaccine-rollout-strategy-faq/#:~:text=the%20vaccines%20will%20be%20rolled,and%20persons%20over%2040%2dyears. https://www.nicd.ac.za/covid-19-vaccine-rollout-strategy-faq/#:~:text=the%20vaccines%20will%20be%20rolled,and%20persons%20over%2040%2dyears. http://sisonkestudy.samrc.ac.za/ https://www.sahpra.org.za/press-releases/sahpra-update-on-vaccine-approvals/ https://www.sahpra.org.za/press-releases/sahpra-update-on-vaccine-approvals/ https://www.sahpra.org.za/press-releases/sahpra-registers-the-covid-19-vaccine-janssen/ https://www.sahpra.org.za/press-releases/sahpra-registers-the-covid-19-vaccine-janssen/ https://doi.org/10.1016/s2213-2600(21)00082-5 https://www.nicd.ac.za/covid-19-vaccine-side-effects-faq/ https://www.nicd.ac.za/covid-19-vaccine-side-effects-faq/ doi:%2010.7196/samj.2021.v111i4.15576 https://www.nicd.ac.za/covid-19-vaccination-reporting-adverse-effects-faq/ https://www.nicd.ac.za/covid-19-vaccination-reporting-adverse-effects-faq/ https://www.who.int/news/item/09-07-2021-gacvs-guidance-myocarditis%20-reported%20with%20covid-19-mrna-vaccines https://www.who.int/news/item/09-07-2021-gacvs-guidance-myocarditis%20-reported%20with%20covid-19-mrna-vaccines https://www.who.int/news/item/09-07-2021-gacvs-guidance-myocarditis%20-reported%20with%20covid-19-mrna-vaccines https://sacoronavirus.co.za/2021/06/24/ministerial-advisory-committee-on-covid-19-vaccines-vmac/ https://sacoronavirus.co.za/2021/06/24/ministerial-advisory-committee-on-covid-19-vaccines-vmac/ https://www.sahpra.org.za/press-releases/sahpra-authorises-the-coronavac-vaccine-with-conditions/ https://www.sahpra.org.za/press-releases/sahpra-authorises-the-coronavac-vaccine-with-conditions/ https://www.nicd.ac.za/vaccination-of-pregnant-and-breastfeeding-women-august-update/ https://www.nicd.ac.za/vaccination-of-pregnant-and-breastfeeding-women-august-update/ sajsm 532.indd original research sajsm vol. 26 no. 3 2014 69 background. the skeletal immaturity of competitive female gymnasts allows for a unique physiological predisposition to injuries as a result of the spine, limbs, ankles and wrists still growing. studies have shown that lower back (spinal) injuries account for approximately 12% of injuries in female gymnasts. objectives. the primary objective of the study was to determine the prevalence of radiological changes in female artistic gymnasts in south africa. a further objective was to determine whether these radiological changes were associated with symptoms and with the amount of time spent training. methods. a sample of 40 female artistic gymnasts with a mean of age 15.2 years (range 10 31) was included in the study. thirty-one were active gymnasts and nine were retired at the time of the current study. measuring instruments included questionnaires and x-rays. results. x-ray analysis of symptomatic versus asymptomatic gymnasts showed no significant differences. of the 18 gymnasts training <25 h/week, 13 (72%) had degenerative changes detectable by x-ray. of the 22 gymnasts training >25 h/week, 15 (68%) had degenerative changes detected by x-ray. radiological changes were higher than those in other studies. conclusion. the prevalence of radiological changes was higher than international norms, however there was little difference between symptomatic and asymptomatic gymnasts. patient self-reports of symptoms had little value in diagnosing change in the lumbar spine. training duration affected the prevalence of changes in the lumbar spine and could be related to conditioning and experience. s afr j sm 2014;26(3):69-72. doi:10.7196/sajsm.532 radiological changes among artistic gymnasts in gauteng province a geldenhuys-koolen,1 bsc (physiotherapy), msc (med) (exercise science); d constantinou,2 mb bch, bsc (med) (hons), msc (med), ffims; y coopoo,2 dphil, facsm 1 private practice, adele geldenhuys physiotherapy, johannesburg, south africa 2 centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: a geldenhuys-koolen (adele@koolcon.co.za) in south africa (sa), women’s gymnastics participation is on the increase.[1] competition season for level 1 4 gymnasts starts in march and ends in june, whereas level 5 and higher gymnasts start their competitions in june and continue through to september. the junior and senior olympic entry female gymnasts start with testing competitions as early as january, and the first major competition takes place in february. qualification trials for world championships and the all africa games take place in sa throughout the year. the gymnasts are also selected for numerous international competitions based on their performances and their rankings with the sa gymnastics federation. gymnastics appears to be associated with a high incidence of injury when compared with most other sporting activities,[2] with the amount of impact applied to the body relatively high in comparison with other sports.[3] the skeletal immaturity of gymnasts also allows for a unique physiological predisposition to injuries because the spine, limbs, ankles and wrists are still growing. studies have shown that lower back (spinal) injuries account for approximately 12% of injuries in wo men’s gymnastics.[4] published case studies show that back injuries tend to have a gradual onset, and involve predominantly advanced-level gymnasts. these studies have also indicated that an increase in skill and competitive level are risk factors for injury.[4] sports-related injuries are of two types. macrotrauma occurs as an acute, perhaps dramatic, event such as a concussion, spinal cord injury, fracture or dislocation. microtrauma occurs as a repeated injury, usually not noticed initially because the injury is microscopic in magnitude, but in which the cumulative trauma leads to pain and, in some cases, significant disability, as occurs with stress fractures. although any number of injuries may occur in all sports, some injuries are recognised to be particularly prevalent in specific sports.[5] in gymnastics, spondylolysis occurs frequently due to the hyperextended positions and rotational forces in gymnastic routines, e.g. back walk-overs.[6] spondylolysis may represent a form of stress fracture. prevention includes abdominal and spinal muscle strengthening. however, more recent evidence regarding specific prevention and treatment is required; the findings in this study may lead to preventive measures. a 2005 study by cohen and stuecker[7] showed the importance of detecting and monitoring the early onset of spondylolysis due to degeneration of the pars interarticularis of the vertebrae. this con d ition is not isolated to gymnastics; however, it has a higher prevalence in sports where the lumbar spine is placed under stress in hyperextension positions, i.e. gymnastics, ballet, swimming (butterfly) or in unilateral sports such as bowling in cricket.[6] imaging studies reported in the medical literature have shown that degenerative disc disease and spinal injuries are more frequent in competitive female gymnasts than in asymptomatic non-athletic people of the same age.[8] although these findings are more prevalent in the competitive gymnast, other studies suggest that they may not 70 sajsm vol. 26 no. 3 2014 be of clinical significance. a study documenting magnetic resonance imaging (mri) findings in symptomatic and asymptomatic olympic gymnasts in the usa, reported that symptomatic patients exhibited radiological changes absent in asymptomatic patients.[9] it is accepted that x-rays may not be appropriate for assessing detail of lumbar spine pathology, but are sufficient for initial evaluation or when recommended by ‘red flags’.[10] the focus of this study was on x-rays rather than mri because mri scans in sa are costly and impractical, especially for the screening of asymptomatic subjects. generally in sa, mri scans are usually performed if the patient is symptomatic and when x-rays show radiological changes and further investigation is indicated. as underlying pathology detected on mri scans may not be the cause of lower back pain, the value of mri scans in refining epidemiological case definitions for lower back pain is limited.[11] the detection of spondylolysis, not uncommon in gymnasts, is most sensitively detected by x-rays;[12] therefore, x-ray imaging plays an important role in this.[13] the review by davis et al.[10] states: ‘the availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatment’. lack of financial resources is an influencing factor in the selection of imaging procedure, and an sa study reviewing the complementary roles of radiology and nuclear medicine stated that cost is an important consideration.[14] in africa, financial constraints and physical access to mri imaging may be improving but is still limited, while x-rays are more readily available.[15,16] as such, the use of x-rays in the context of assessing radiological findings and lower back pain in the african context is currently appropriate.[17] owing to the lack of recent research on x-ray changes in gymnasts and the questions relating to the clinical significance of these changes, there is a need to investigate the prevalence of radiological changes in female artistic gymnasts in sa, and to correlate these with symptoms. it is also important to note that, to date, there has been no research conducted on artistic gymnasts in sa because the sport has only recently become popular.[1] to date, there have been no radiological studies conducted on artistic gymnasts in sa,[1] nor is there current research on radiological changes among the broader gymnast population. the study was approved by the faculty postgraduate studies committee, and ethics approval was granted by the university human research ethics committee (medical). questionnaires and radiological tests were used to investigate history, type of training, experience and injuries sustained in the participating gymnasts. one of the benefits of this study was ascertaining the state of spinal health of this group of gymnasts. based on the results, group exercise programmes could be created to prevent further back injuries, and to prevent progression of back injuries where they exist. methodology radiological imaging of the participating gymnasts was performed with anteroposterior, lateral and oblique views. the x-rays were examined and reported on by a single radiologist. the radiologist transcribed the findings on a standardised reporting form. once all x-rays were examined and reported on, they were reviewed by a second independent radiologist, who, using the same criteria, reexamined and reported on the films. both radiologists reached the same conclusions. sample design owing to the small population size, a census was more practical than drawing a sample. an attempt was made to conduct a census of all currently active elite gymnasts registered with clubs in gauteng, specifically those falling into the subcategory of artistic gymnasts. of the 20 registered gymnastics clubs in gauteng, seven clubs offered a high-performance programme. four of these clubs did not have any elite gymnasts at the time of the study. the remaining three clubs were included in the study. once consent was obtained, participants were given a questionnaire to complete. the participants were able to take the questionnaires home to complete with the help of their parent/ guardian. all female artistic gymnasts born between 1990 and 2000, and who were currently training ≥15 h/week for a minimum of 3 years, were considered for inclusion. the training programme had to be a highperformance programme. only gymnasts who consented, or in the case of minors who assented and whose parents consented for their participation, were included in the study. in total, 31 currently active artistic gymnasts were included in the study, while four qualifying gymnasts refused to participate, yielding a response rate of 89%. a cohort of nine former elite-level gymnasts who had retired from the sport was also included in the study in order to gather radiological data for comparison with the currently active group. there was no age limit for the retired group; the only requirement being that they had trained for at least 3 years, and for ≥15 h/week in a high-performance programme. measuring instruments questionnaires questionnaire content validity was ensured by obtaining input from gymnasts, while test-retest reliability was also assessed, achieving 100% agreement between both tests. x-rays x-rays were taken by three radiographers, following the same procedures for each view. the x-ray machines used were the phillips omnidiagnost, siemens iconos 100 and siemens sieragraph b. the films were processed in a konical minolta srx201, using fujifilm hr u30. the x-rays were taken in the following views, using the procedure as set out in clark’s positioning in radiography. [18] each subject underwent five lumbar spine x-ray views, namely anteroposterior (ap), lateral, oblique, stress views (extension and flexion) and lateral coned l5, s1 views. results descriptive statistics were used to analyse the data collected using questionnaires, as well as the data resulting from the radiological analysis. in total, 90% of gymnasts reported a peripheral injury, while 50% reported a back injury. peripheral injuries: self-reports based on the data collected from the questionnaires, 90% of the 40 gymnasts reported having sustained a peripheral injury (all injuries excluding back injury). prevalence rates among currently active gymnasts were similar to the retired group: 28 (90%) of the 31 current sajsm vol. 26 no. 3 2014 71 gymnasts reported peripheral injuries, while 8 (88%) of the 9 retired gymnasts reported peripheral injuries. of the 36 gymnasts with peripheral injuries, 33 (92%) of the injuries happened during training and 3 (8%) during competition. back injuries: self-reports of the 40 gymnasts who completed the questionnaire, 50% reported sustaining a back injury, either before the time of data collection or before the time of retirement. of the 20 gymnasts with back injuries, 75% reported the injuries to be located in the lumbar spine, with 15% located in the thoracic spine and 10% located in the cervical spine. back injuries: x-rays spinal x-rays were taken of each gymnast (n=40) and analysed for the following changes: scoliosis, spondylolysis, spondylolisthesis and degenerative changes (disc and facet joint degeneration, osteophyte formation). among those who reported back injury, the most prevalent condition identified by radiological analysis was scoliosis (75%), followed by degenerative changes (70%) (table 1). the least common change was spondylolysis. interestingly, among those who did not report back injury, a high percentage was subsequently shown to have changes they were unaware of. a similar pattern emerged, with scoliosis and degenerative changes being most prevalent (table 2). in order to obtain an indication of whether the prevalence levels of this gauteng study deviated substantially from international data, we compared our data with prevalence levels reported in a meta-analysis conducted by caine and nassar.[4] given the substantial variation from study to study, the lowest and highest values are reported to provide an indication of the range (table 3). prevalence rates reported internationally showed lower prevalence of scoliosis (both lowest and highest prevalences were below the prevalence rates in gauteng). in contrast, in gauteng, spondylolysis and spondylolisthesis had prevalence rates between the lowest and highest rates reported internationally. training exposure time and radiological changes gymnasts were allocated to either a low or high training exposure group. since elite gymnasts train for a minimum of 25 h/week, this was used as a cut-off point in order to evaluate the effect of training exposure on radiological changes. gymnasts who trained <25 h/week were allocated to the lowexposure group, while gymnasts who trained for >25 h/week were allocated to the highexposure group. the results showed that gymnasts in the high-exposure group were less likely to have evidence of degenerative changes in the spine than those in the lowexposure group, with prevalence rates of 68% v. 72%, respectively. discussion scoliosis, spondylolysis, spondylolisthesis and other signs of degenerative change were examined using x-rays. the results showed that there can be significant structural deficit in the lumbar spines of gymnasts, even without reports of pain or back injury. differences in actual injur y prevalence between symptomatic and asymptomatic gymnasts, as confirmed by x-ray, were small. this means that the presence or absence of symptoms is an unreliable indicator of injury. further, this could mean that asymptomatic gymnasts may unknowingly expose themselves to excessive training and competition, leading to faster progression of changes. therefore, imaging should be performed on gymnasts to monitor spinal changes and possibly initiate measures to prevent severe injury. the findings of this study also showed that exposure time to gymnastics has an effect on the prevalence of back injuries. back injuries occurred more in gymnasts who trained for <25 h/week. however, the results of other studies have concluded that greater exposure to training was directly related to an increased risk of injury.[1] this may be due to a non-linear relationship between exposure time and back injury prevalence, which the discretised measure of exposure used in this study was unable to detect. further research should be conducted with larger samples for a more refined measure of exposure, with a larger number of exposure categories. results showed that gymnasts training and competing at higher levels experienced more back injuries. this was also found in retired gymnasts who competed at senior olympic level. this correlates with findings of other studies[1] where older gymnasts had higher exposure frequencies. whether age is another risk factor for injury, because gymnasts competing at higher levels are generally older, is unknown. table 1. prevalence of radiological changes, subject reported back injury (n=20) total, % total, n current, n retired, n scoliosis 75 15 11 4 degenerative changes 70 14 11 3 spondylolysis 15 3 2 1 spondylolisthesis 20 4 3 1 table 2. prevalence of radiological changes, subject did not report back injury (n=20) total, % total, n current, n retired, n scoliosis 75 15 12 3 degenerative changes 85 17 12 5 spondylolysis 15 3 1 2 spondylolisthesis 15 3 2 1 table 3. prevalence of radiological changes, international studies lowest reported, % highest reported, % scoliosis 11.5 19.2 spondylolysis 9.1 32.8 spondylolisthesis 3.3 15.4 72 sajsm vol. 26 no. 3 2014 study limitations limitations include: (i) the small, localised population, limited to the gauteng province of sa; (ii) no consideration given to the role of genetic differences related to ethnic group; and (iii) the exact gymnastic routines were not described or distinguished, which can be seen as a limitation as different moves and routines could have different effects. conclusion while it is well-known that degenerative conditions and other structural changes such as scoliosis, spondylolysis and spondylolisthesis are more prevalent within the gymnastic population than the general population, this has not been demonstrated among elite artistic gymnasts. symptoms based on self-reports are not reliable indicators of the presence of back injury. the use of x-rays in the context of limited resources and accessibility is appropriate in gymnasts with high volumes of training as both symptomatic and asymptomatic groups showed similar prevalence rates when using x-rays as the measuring instrument. therefore, it is important to evaluate radiological spinal changes in gymnasts who are training at high performance level and competing professionally, both in symptomatic and asymptomatic gymnasts. the timing of when this should be done is not entirely clear. the importance of proper rehabilitation after injury and before return to high-level activity is also highlighted to prevent further injury and reduce the rate of early retirement from the sport. proper conditioning of gymnasts is needed to prevent injury during skill acquisition and performance. training duration affects the prevalence of changes in the lumbar spine; however, the results contradict prior research, suggesting further research is required. references 1. adamson i. gymnastics injuries: a quantitative profile of athletes in the greater durban area. dissertation submitted in partial compliance with the requirements for a master’s degree in technology: chiropractic in the department of chiropractic at the durban institute of technology. 2006. http://www.dut.ac.za 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[http://dx.doi.org/10.1016/s00049514(14)60444-x] 3. daly rm, bass sl, finch cf. balancing the risk of injury to gymnasts: how effective are the counter measures? br j sports med 2001;35(1):8-18. [http://dx.doi. org/10.1136/bjsm.35.1.8] 4. caine dj, nassar l. gymnastic injuries. med sport sci 2005;48:18-58. [http://dx.doi. org/10.1159/000084282] 5. boden bp, osbahr dc, jimenez c. low-risk stress fractures. am j sports med 2001;29(1):100-111. 6. bruggeman gp. mechanical load in artistic gymnastics and its relation to apparatus and performance. in: leglise m, ed. symposium medico-technique. lausanne, switzerland: international gymnastics federation, 1999:17-27. 7. cohen e, stuecker rd. magnetic resonance imaging in diagnosis and followup of impending spondylolysis in children and adolescents: early treatment may prevent pars defects. j pediatr orthop b 2005;14(2):63-67. [http://dx.doi. org/10.1097/01202412-200503000-00001] 8. swärd l, hellstrom m, jacobsson b, pëterson l. back pain and radiologic changes in the thoraco-lumbar spine of athletes. spine 1990;15(2):124-129. [http://dx.doi. org/10.1097/00007632-199002000-00015] 9. bennett dl, nassar l, delano, mc. lumbar spine mri in the elite-level female gymnast with low back pain. skeletal radiol 2006;35(7):503-509. [http://dx.doi.org/10.1007/ s00256-006-0083-7] 10. davis pc, wippold fj, brinberg ja, et al. acr appropriateness criteria® on low back pain. j am coll radiol 2009;6(6):401-407. [http://dx.doi.org/10.1016/j. jacr.2009.02.008] 11. endean a, palmer kt, coggon d. potential of magnetic resonance imaging findings to refine case definition for mechanical low back pain in epidemiological studies: a systematic review. spine 2011;36(2):160-169. [http://dx.doi.org/10.1097/ brs.0b013e3181cd9adb] 12. tallarico ra, madom ia, palumbo ma. spondylolysis and spondylolisthesis in the athlete. sports med arthrosc rev 2008;16(1):32-38. [http://dx.doi.org/10.1097/ jsa.0b013e318163be50] 13. keller ms. gymnastics injuries and imaging in children. pediatr radiol 2009;39(12):12991306. [http://dx.doi.org/10.1007/s00247-009-1431-2] 14. warwick j, lotz j. integrated imaging: the complementary role of radiology and nuclear medicine. south african journal of radiology 2013;17(4):149-153. [http://dx.doi. org/10.7196/sajr.1033] 15. ogbole gi, adeleye ao, adeyinka ao, ogunseyinde oa. magnetic resonance imaging: clinical experience with an open low-field-strength scanner in a resource challenged african state. j neurosci rural pract 2012;3(2):137-143. [http://dx.doi.org/10.4103/09763147.98210] 16. potchen mj, kampondeni s, birbeck gl, et al. magnetic resonance imaging in malawi: contributions to clinical care, medical education and biomedical research. malawi med j 2011;23(2):62-66. [http://dx.doi.org/10.4314/mmj.v23i2.70753] 17. igbinedion boe, akhigbe a. correlations of radiographic findings in patients with low back pain. nig med j 2011;52(1):28-34. 18. whitley as, sloane c, hoadley g, moore ad. clarke’s positioning in radiography. 12th ed. london: hodder arnold, 2005. original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license a prevalence of running-related injuries among professional endurance runners in the rift valley, kenya rc koech,1 bsc physiotherapy; b olivier,3 phd; n tawa,1, 2 phd 1 department of physiotherapy, jomo kenyatta university of agriculture and technology, kenya 2 centre for research in spinal health and rehabilitation medicine, department of physiotherapy, jomo kenyatta university of agriculture and technology, kenya 3 department of physiotherapy, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: rc koech (kimkoech254@gmail.com) endurance or long-distance running is a continuous run on the track or off the track over distances ranging from eight hundred metres extending to full marathons and ultramarathons.[1] kenyan endurance runners have featured prominently in races organised by the world cross-country championships (wccc) and the international association of athletics federations (iaaf). [2] according to fisher, nearly 70% to 80% of endurance running winners in any global event since the late 1980s are of kenyan descent. [3] the issue of injuries among runners has been a concern to various stakeholders, including researchers. as a result, a growing number of studies have been published recently with the aim of addressing this problem. for instance, a systematic literature review on predisposing factors, incidence and prevention of injuries in endurance running by videbæk et al. [4] revealed that injury prevalence rates among recreational and novice distance runners were higher than those of marathoners. the differences in incidence rates were significant in competitive runners, i.e. marathoners, having injury incidence rates as low as 2.5 to 7.4 per 1 000 hours while non-competitive runners, such as novice runners, registered injury incidence rates of up to 17.8 injuries per 1 000 hours of exercise. [4] small and relph [5] showed that 26 runners sustained 108 lower extremity injuries (89%) in a multiday marathon lasting 27 days, indicating an average of four injuries per marathon runner. however, the study suggested that further investigation of the prevalence and predisposing factors using a larger sample size is required to allow proper generalisation of results. vitez et al. [6] investigated running-related injuries in runners of the ljubljana marathon in slovenia and reported that a third of these marathon runners suffered at least one mild running injury during the season, with a 53% lifetime of running injury prevalence. the predominant injury region was the knee (30%). iliotibial band syndrome, achilles tendonitis and tibial stress syndrome were among the most common injuries reported by endurance runners (tonoli et al. [7]). mbarak et al. [8] studied running-related musculoskeletal injuries, risk factors and treatment among short-, mediumand long-distance kenyan runners pointing out the frequency of injuries at the injury sites. hamstring injuries were the commonest (43/108 cases; 40%), followed by knee injuries (33/108 cases; 31%). however, the study did not specifically indicate the overall prevalence among the runners. therefore no study has focused specifically on the prevalence of running-related injuries among endurance runners in kenya. furthermore, most studies have been carried out in other contexts and have seldom focused on professional endurance runners of international stature. kenya has a unique context for running injuries and local findings can be used to better inform injury prevention approaches and ultimately benefit running performance. this study therefore sought to establish the injury prevalence among professional endurance runners in the rift valley, kenya. methods this cross-sectional survey was conducted in the rift valley region of kenya. based on registration data from athletics kenya (athletics governing body), the study targeted 2 481 endurance runners who had participated in both local and international running competitions. calculations using a proposed formula by cochran [9] gave a sample size of 209 professional endurance runners. the study used stratified background: injuries related to endurance running have attracted attention as the sport has become more competitive, and as athletes seek to improve their performance. consequently, endurance runners are increasingly becoming more susceptible to lower extremity running injuries. objectives: the aim of this study was to establish the prevalence of running-related injuries among professional endurance runners in the rift valley, kenya. methods: we used a cross-sectional survey design targeting professional endurance runners who had participated in both local and international running competitions. the sample size consisted of 209 respondents selected through stratified and simple random sampling techniques, of which 167 participated in the study. a self-administered questionnaire was used to collect data on the prevalence of injuries among the endurance runners. the data were analysed using descriptive statistics. results: the prevalence of running injuries was 63% (n=106). the prevalence among males (n=64; 69%) was higher in comparison with that of females (n=42; 57%). the posterior thigh was the most common site for injuries among the athletes (n=87; 52%), followed by the lower back (n=78; 47%) and ankle (n=63; 38%). conclusion: the prevalence of running-related injuries was high among professional kenyan endurance runners compared to other populations. these findings therefore form the basis of future research to explore the mechanisms behind the injuries and the feasibility of targeted injury prevention programmes. keywords: occurrence, injuries related to running, experienced runners, kenya s afr j sports med 2021;33:1-4. doi: 10.17159/2078-516x/2021/v33i1a10690 mailto:kimkoech254@gmail.com http://dx.doi.org/10.17159/2078-516x/2021/v33i1a10690 https://orcid.org/0000-0003-2106-9384 https://orcid.org/0000-0003-1770-8761 https://orcid.org/0000-0001-9287-8301 original research sajsm vol. 33 no. 1 2021 2 random sampling to distribute the sample size based on gender (male, n=119; female, n=90). a simple random sampling technique was then used to select the study’s participants, which meant that they had to have participated in one official local or international competition. moreover, this population was chosen because of their availability as most of the runners were resident and training within the athletics kenya approved and recognised training camps. runners below age of 18 years, running races less than 800 metres in length, and amateurs and foreigners were excluded from participating in the study. the study used a pretested, self-administered questionnaire to collect the data. a running injury was defined as any muscle, bone or joint injury of the lower extremity and back (i.e. foot, ankle, calf, shin, knee, thigh, hip, lumbar region) resulting from participating in a training and/or competitive sports activity resulting in the runner missing out for >48 hours. an acute injury was defined as an injury caused by a particular and recognizable traumatic incident experienced by the athlete during training or competition whereas overuse injury was defined as having occurred as a result of recurrent microtrauma that could not be traced to a particular event or incident. to ascertain validity, the questionnaire was reviewed by two sports physiotherapists and twenty endurance runners prior to being administered to the respondents. the questionnaires administered to the runners had to be returned within two weeks. the researcher was available via mobile phone and at the training camps to clarify uncertainties where needed, while the respondents were completing the questionnaires. the data collection process took place over a period of 16 weeks (july-october) in 2019. the data were processed using the statistical package for social sciences (spss version 22.0) and analysed using descriptive statistics. permission to conduct the study was given by the relevant research regulatory bodies, and the endurance runners voluntarily consented to participate in the study after being assured that the data collected will be safe, secure and confidential. results the demographic characteristics of the runners a total of 182 questionnaires were returned. fifteen of these were incomplete and thus could not be used for the study, leading to a final data analysis on 167 questionnaires. the demographic characteristics are presented in table 1. the findings indicate that the majority of the respondents were male (n=93; 56%); aged 26-30 years (n= 63; 38%); had running experience of between 1-3 years (n=84; 50%); participated in both local and international competitions (n=62; 37%); the highest level of education was secondary level (n=120; 72%); and they depended on running as an occupation (n=127; 76%). the injury prevalence of running injuries the responses on running-related injuries sustained within the previous year are shown in table 2. the majority (n=106; 64%) of the athletes had experienced a running-related injury at some point within the previous year. the prevalence of running injuries was higher among males (n=64/93; 69%) than females (n=42/74; 57%). an overuse injury (n=74/106; 70%) was the table 1. the demographic characteristics of the runners (n=167) variable category frequency (n) percentage (%) gender male 93 56 female 74 44 age in years 16 – 20 33 20 21 – 25 50 30 26 – 30 63 38 31 – 35 18 11 36 – 40 1 1 41 – 45 1 1 46 – 50 1 1 professional running experience in years 1 – 3 84 50 4 – 6 57 34 7 – 10 26 16 level of competitions local 54 32 international 51 31 both 62 37 primary 22 13 level of education secondary 120 72 certificate 12 7 diploma 7 4 undergraduate 5 3 postgraduate 1 1 occupation other than athletics yes 40 24 no 127 76 table 2. running-related injuries sustained and their classification during the previous year (n=167 partcipants) have you experienced a running injury within the previous year? indicate the type of injury sustained within the previous year gender yes no total acutea overuseb total female n 42 32 74 15 27 42 % 57 43 100 36 64 100 male n 64 29 93 17 47 64 % 69 31 100 27 73 100 total n 106 61 167 32 74 106 % 63 37 100 30 70 100 a acute injury is injury sustained from a particular event that can be identified by the athlete. b overuse injury results from recurring microtrauma that cannot be traced to a single event. original research 3 sajsm vol. 33 no. 1 2021 most common type of injury among the runners. the athletes were further asked to indicate the number of times they had experienced runningrelated injuries in their different body parts in the previous year while training or during running competitions. these results are given in table 3. posterior thigh injuries (n=87; 52%) were most common among the athletes, followed by lower back pain (n=78; 47%) at least once in the previous year while training or during running competitions. the third and fourth most prevalent injuries sustained during training and competition, respectively, were ankle (n=63; 38%) and groin (n=49; 29%) injuries. discussion prevalence of injuries related to endurance running was n=106 (64%) which were incurred during the previous season. the majority of those injured suffered overuse injuries (n=74; 70%) possibly as a result of the combined effect of long-lasting fatigue beyond their specific biomechanical capability.[10] in addition, the majority of the runners might have been predisposed to running injuries due to the observed overtraining behaviour aimed at coping with the competitiveness of long-distance running in kenya.[8] the injury rates reported among the athletes were higher than those of vitez et al.[6] in slovenia who reported that a third of the ljubljana marathoners experienced at least one mild running injury in the season. this is considered to be so because of the low sensitivity by the use of >2 weeks’ time-loss based on the injury definition by vitez et al. similarly, the injury prevalence among the endurance runners in this study was lower (n=167; 63%) than those found by ellapen et al. [11] in kwazulu-natal in south africa who observed that within a year, 90% of the 200 half marathon recreational runners suffered at least one running injury. whereas the current study analysed data on 167 professional endurance runners and defined ‘injury’ as an occurrence happening during training and/or competition which made a runner lose more than 48 hours. ellapen et al. dealt with 200 half marathon runners and classified an ‘injury’ as an incident that caused more than 24 hours of time lost, thus explaining the variation between the two studies. according to tonoli et al. [7] experienced runners tend to incur fewer injuries because there is the development of an innate ability to recognise the onset of an injury thus preventing its severity compared to novice runners. this concurs with the result in table 1 that the majority of the endurance runners (n=84; 50%) had professional running experience of between one to three years. more males (n=64; 69%) than females (n=42; 57%) reported experiencing an injury within the 12-month period of our study. since the external training conditions were the same for both females and males, this finding implies that the variation of injuries across gender lines is possibly due to internal factors i.e. anatomical, biomechanical and/or physiological.[12] the difference in injury prevalence across both genders are similar to, although much higher than those of van der worp et al. [13] in the netherlands who found that male runners were more susceptible to calf and hamstring injuries, whereas women were more prone to sustaining hip injuries. it can therefore be concluded that men were at greater risk than women for developing running-related injuries. running-related posterior thigh injuries (n=87; 52%) was the most common injury site in both men and women, followed by the lower back (n=78; 47%). the running surface in the rift valley region is characterised by hills, valleys and flat terrain. therefore, running in this region predisposes a runner to excessive loading of the quadriceps muscles (uphill training) resulting in an agonist and antagonist muscle imbalance with a table 3. number of injuries per injury site in the previous year (n=167 participants) injury site participants without injury participants with injury four or more times three times twice once lower back n 89 78 26 17 9 26 % 53 47 33 22 12 33 buttocks n 126 41 10 3 7 21 % 75 25 25 7 17 51 groin n 118 49 5 7 13 24 % 71 29 10 14 27 49 hip n 121 46 8 9 13 16 % 72 28 17 20 28 35 anterior thigh n 121 46 10 11 13 12 % 72 28 22 24 28 26 posterior thigh n 80 87 21 13 19 34 % 48 52 24 15 22 39 knee n 124 43 16 4 11 12 % 74 26 37 9 26 28 upper leg n 125 42 12 8 11 11 % 75 25 29 19 26 26 lower leg n 122 45 9 6 16 14 % 73 27 20 13 36 31 ankle n 104 63 8 9 3 43 % 62 38 13 14 5 68 foot n 140 27 3 5 8 11 % 84 16 11 18 30 41 toes n 132 35 3 6 6 20 % 79 21 9 17 17 57 injuries include acute and overuse injuries. original research sajsm vol. 33 no. 1 2021 4 higher prevalence of posterior thigh injuries. [14] it can be further suggested that high posterior thigh injuries were as a result of poor running methodology seen amongst the kenya runners that involved inadequate warm-up, limited stretches and eccentric strength training. [8] the results in this study on the prevalence of posterior thigh injuries were, however, much higher than those of opar et al. [15] who found that posterior thigh injuries accounted for 24% of the overall of the lower extremity running-related injuries. the comparatively high prevalence of injuries in this study compared to those of opar et al. could be attributed to the fact that their study was carried over a duration of three years, while this study was based on the respondent’s recollection of injuries for the previous year. the injury prevalence of the lower back region (n=78; 47%) indicates that the runners might have been more predisposed to this injury due to excessive biomechanical overload as a result of overtraining, leading to increased fatigue and stress on the intervertebral disc. [9] the other common injury site reported by the athletes was the ankle (n=63; 38%). large amounts of high-intensity running, rapid increase in training mileage and/or variation of running surfaces seen among the runners could possibly be an injury risk for ankle injuries, specifically if running on a hard surface. [8] these findings were slightly higher than those of tonoli et al. [7] who found the prevalence rate of ankle injury among marathoners to be 25%. however, the ankle injury prevalence in this study was much higher than the 17 % prevalence rate reported by small and relph [5] among multiday marathoners. the high prevalence observed in this study compared to that of small and relph, [5] could be attributed to the fact that our study focused on professional camp-based runners, while the previous study focused on recreational marathoners. this study is the first to report on the epidemiology of injuries amongst kenyan endurance runners and these findings would be useful in future research. a limitation of this study is that only 167 questionnaires were included in the analysis, while the calculated sample size was 209. although the findings reported here still makes a valuable contribution to the literature, caution should be taken in generalising results to the wider endurance runner population. conclusion the prevalence of running-related injuries among professional kenyan endurance runners was 63% in a previous season. this forms the basis of future research to explore mechanisms behind running injuries and the effectiveness of intervention programmes to prevent injury. future studies could also explore the extreme dominant performance of kenyan endurance runners despite the high injury prevalence reported. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: our special thanks goes to all participants who were involved in the study. author contributions: all authors have contributed substantially and were involved in the following phases of (i) conception, design, analysis and interpretation of data; (ii) drafting or critical revision for important intellectual content; and (iii) approval of the version to be published. references 1. pescatello ls , roth sm (eds.) exercise genomics. s.l.: humana press. 2011. 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[doi:10.1249/mss.0b013e318279a10a] [pmid: 23247672] 11. ellapen tj, satyendra s, morris j, et al. common running musculoskeletal injuries among recreational half-marathon runners in kwazulu-natal. s afr j sports med 2013; 25(2), 39-43. [doi: 10.17159/2078-516x/2013/v25i2a372] 12. taimela s, kujala um, osterman k. intrinsic risk factors and athletic injuries. sports med 1990; 9(4): 205–215 [doi: 10.2165/00007256-199009040-00002] [pmid: 2183329] 13. van der worp mp, ten haaf ds, van cingel r, et al. injuries in runners; a systematic review on risk factors and sex differences. plos one 2015; 10(2): e0114937. [doi: 10.1371/journal.pone.0114937] [pmid: 25706955] 14. hu x, pickle nt, grabowski am, et al. muscle eccentric contractions increase in downhill and high-grade uphill walking. front bioeng biotechnol 2020; 8: 573666 [doi: 10.3389/fbioe.2020.573666] [pmid: 33178672] 15. opar da, drezner j, shield a, et al. acute hamstring strain injury in track-and-field athletes: a 3-year observational study at the penn relay carnival. scand j med sci sports 2014; 24(4): e254– 259. [doi: 10.1111/sms.12159] [pmid: 24330073] file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1007/978-1-60761-355-8_1 doi:%2010.1249/mss.0b013e3181badd67 https://www.theatlantic.com/international/archive/2012/04/%5d file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1007/s40279-015-0333-8 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.4172/2324-9080.1000280 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.4172/2324-9080.1000280 https://doi.org/10.1515/sjph-2017-0027 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.4314/eaoj.v13i1 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.4314/eaoj.v13i1 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:10.1249/mss.0b013e318279a10a file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.17159/2078-516x/2013/v25i2a372 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.2165/00007256-199009040-00002 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.2165/00007256-199009040-00002 doi:%2010.1371/journal.pone.0114937 doi:%2010.3389/fbioe.2020.573666 doi:%2010.3389/fbioe.2020.573666 doi:%2010.1111/sms.12159 sajsm 553.indd sajsm vol. 26 no. 3 2014 87 review the role of prohormones, ‘classic’ and ‘designer’ steroids, clenbuterol, peptide hormones and newer molecules causing concern in dietary supplements is discussed. apart from their potential adverse effects on athletes’ health, their non-achievement of increased strength and muscle size, trace quantities present in contaminated dietary supplements can lead to failed doping tests. the methodologies used for the identification and determination of prohibited substances in very low concentrations, mainly liquid chromatography and mass spectrometry, are also addressed. of concern is the anticipation that the number of dietary supplements containing (not yet) prohibited designer steroids and other performance-enhancing newer chemical entities will increase. athletes, coaches and sports doctors should therefore be provided with information regarding dietary supplements and be advised to minimise risks for non-intentional ingestion of forbidden substances by using safe products listed on databases, such as those obtainable in the netherlands and germany. s afr j sm 2014;26(3):87-90. doi:10.7196/sajsm.553 dietary supplements containing prohibited substances: a review (part 2) p van der bijl, bsc hons (chem), bsc hons (pharmacol), bchd, phd, dsc emeritus professor and former head, department of pharmacology, faculty of medicine and health sciences, stellenbosch university, tygerberg, cape town, south africa; and invited foreign professor, department of pharmacology, pirigov’s russian national research medical university, moscow, russia corresponding author: p van der bijl (pietervanderbijlcpt@gmail.com) in part 1[1] the focus was on the presence of stimulants in dietary supplements, while the current article deals with ‘classic’ and ‘designer’ steroids, clenbuterol, peptide hormones and newer molecules that cause concern in sports nutrition due to their accidental intake as contaminants. prohormones it has been shown in a previous study that ~15% of dietary supplements comprising mainly vitamins, minerals, proteins and creatine contained undisclosed anabolic androgenic steroids.[2] these steroids were mainly prohormones, referring to androgenic precursors that are enzymatically activated in vivo to the anabolic steroid testosterone and its derivatives. in the aforementioned study, it was assumed that these prohormones were probably the result of contamination before or during manufacturing processes. nevertheless, the quantities of prohormone detec ted in thes e supplements could have resulted in infringements of doping regulations. prohormones are viewed by many consumers as natural compounds to promote strength and muscle mass, change body composition and improve general feelings of wellness with fewer adverse effects than testosterone itself or other synthetic androgenic steroids.[3] furthermore, prohormones are perceived and commercially promoted as legal alternatives to testosterone, with comparable anabolic effects. however, prohormones are listed as prohibited substances on the world antidoping agency (wada) list and are illegal to sell or import in many countries. cholesterol is metabolised by multiple enzyme systems into testosterone via a number of androgenic intermediates (prohormones), including dihydroepiandrosterone (dhea) (fig. 1). the biosynthetic pathway via dhea leads to the production of androstenedione (dione) and androstenediol (diol). these intermediates can also be converted to the oestrogens, which may cause gynaecomastia and hepatic dysfunction. to counteract cholesterol pregnenolone 17-α-hydroxypregnenolone dehydroepiandrosterone (dhea) androstenediol (diol) progesterone 7-α-hydroxyprogesterone androstenedione (dione) testosterone aromatase oestrone oestriol oestradiol fig. 1. outline of major pathways in the biosynthesis of steroid hormones. 88 sajsm vol. 26 no. 3 2014 these adverse effects, some athletes use prohormones out of the competition season in cycles lasting 4 12 weeks, either alone or in a stacking manner, i.e. taking multiple compounds with different oestrogenic potential simultaneously. alternatively, users may follow a pyramid mode, taking the highest doses in midcycle. additionally, selective oestrogen receptor modulators or aromatase inhibitors (fig. 1) may be taken to attenuate oestrogenic effects, and androgenic herbal products taken to diminish the low period between cycles. [3,4] however, two wellconducted clinical studies have not shown dhea, dione or diol to produce any advantageous anabolic or ergogenic effects at all, but have confirmed the risk of adverse effects. in particular, in one of the studies, ldl-cholesterol/hdl-cholesterol ratios were increased by 11%, significantly elevating the risk for cardiovascular disease and reducing luteinising hormone levels, which may decrease testicular and adrenal testosterone production.[3] other prohormones, e.g. those of the much-used/abused anabolic steroid 19-nortestosterone (nandrolone), have also appeared on the market.[5] one of these prohormones, norandrostendione, administered as a single dose, has been shown to lead to detectable urinary quantities of the main metabolite (19-norandrosterone) of the parent steroid nandrolone for a period >10 days.[5] classic anabolic steroids steroid structures have perhydrocyclopentanophenanthrene nuclei comprising four rings (a, b, c and d), as represented by the structure of testosterone (fig. 2). loci where modifications occur as well as examples of typical reactions, resulting in structural modifications to the steroid nucleus, are also shown. furthermore, steroids can be classi fied into six groups according to the number of carbon atoms, i.e. gonanes (c17), estranes (c18) (e.g. oestradiol and oestrone), andro stanes (c19) (e.g. testosterone and andro stenedione), pregnanes (c21) (e.g. pro gesterone and cortisol), cholanes (c24) (e.g. cholic acid and desoxycholic acid) and chole stanes (c27) (e.g. cholesterol). with the exception of the cholanes, steroids are precursors or natural hormones that, depending on their in vivo functions, can be divided into oestrogens, androgens, glucocorticoids and mineralocorticoids. the steroid category of compounds includes the classic anabolic steroids, e.g. metandienone, stanozol, boldenone, oxandrolone, dehydro chloromethyl-testosterone, etc., which have been found in high amounts (>1 mg/g) in certain dietary supplements and vitamin preparations that are freely available on the market. these steroid ingredients were either listed on package labels under some other chemical/non-approved name or not disclosed at all. concentrations of these steroids in the supplements were of such orders that even within the limits of recommended supplement intake, supratherapeutic doses of these substances would be ingested. many athletes and other individuals in the population at large, including women, adolescents and children, regularly consume dietary supplements in quantities beyond the safe daily recommended doses, and therefore adverse effects in these groups of users could be severe. in men, acne, testicular atrophy, prostate enlargement, decreased spermatogenesis, infertility, impotence and changes in libido may occur.[6] furthermore, gynaecomastia, which may require surgical intervention, can also occur; some male users of steroids concurrently use tamoxifen or other agents to prevent or treat this condition. in women using steroids, acne, potentially irreversible masculinisation, clitoris enlargement, menstrual irregularities and changes in libido may result. in both sexes, psychiatric effects, e.g. aggression (‘roid’ rage), psychoses, manic episodes, panic disorders, depression, etc. have been documented. long-term steroid use has also been associated with dependency and a withdrawal syndrome associated with suicidal thoughts, an increased incidence of tumours and premature mortality.[6] of particular concern are the effects of steroids on cholesterol and lipid metabolism, hypercalcaemia, electrolyte and fluid disturbances, hypertension and thrombotic events, e.g. emboli, myocardial infarction and cerebrovascular accidents, the latter two conditions possibly resulting from an increase in platelet aggregation and erythrogenesis. in adolescents and children, virilisation and premature closure of the epiphyseal plates, which may result in stunted growth, have been described. most of the classic anabolic steroids are methylated in the 17-position of the d-ring of the perhydrocyclopentanophenanthrene nucleus (fig. 2), a molecular feature that is associated with high hepatoxicity and carcinogenicity.[5] while the commercial sources of these steroids on the world market are not always known, it appears as if many of them are sourced from chinese bulk manufacturers and are intentionally incorporated into dietary supplements by unscrupulous companies.[5] designer steroids these steroid molecules were synthesised some 5 decades ago and evaluated in preclinical studies for their anabolic and androgenic effects.[7] they are not listed as components of any currently available pharmaceuticals for clinical use, are not on the wada list of prohibited substances and are manufactured exclusively for the dietary supplement black reduction 19 18 o oh reduction methylation alkylation esteri�cation oxidation glucuronidation or sulphation cyclopentanoperhydrophenanthrene structure hydroxylation 1 2 3 4 5 a b c d 10 11 9 8 7 6 12 13 14 15 16 17 fig. 2. some structural modifications of the steroid nucleus, using the testosterone molecule as an example. sajsm vol. 26 no. 3 2014 89 market. examples of such agents, to name but a few, are prostanozol, methasterone and andostatrienedione, and to date more than 40 such designer steroid molecules have been detected in laboratories.[7] little is known regarding their pharmacological actions and safety profiles in humans. they are either listed under some other chemical/non-approved name or are not disclosed at all on dietary supplement labels. should metabolites of these designer steroids be detected in an athlete’s urine, doping infringement charges would probably ensue. clenbuterol many athletes who claim that they suffer from asthma or exerciseinduced asthma use metered-dose inhaled β2-agonists for alleviating their symptoms of bronchoconstriction. while the inhalational β2agonists such as terbutaline, albuterol and salmeterol are permitted for use by athletes by the wada, oral and injectable forms of these pharmaceuticals are not. however, some of these β2-agonists, e.g. clenbuterol, are considered anabolic substances by some sportsgoverning agencies. hitherto, two cases have been described in which dietary supplements contained therapeutic and supratherapeutic doses of 30 µg/tablet and 2 mg/capsule of clenbuterol, respectively.[8] in the supratherapeutic preparation, which contained 100 times the therapeutic dose of clenbuterol, the presence of this β2-agonist was not disclosed on the package label. peptide hormones over-the-counter dietary supplements are frequently promoted by manufacturers as being able to increase human growth hormone levels in the body. however, a review has shown that while human growth hormone does increase lean body mass, it has no beneficial effect on strength or exercise capacity in trained athletes.[9] however, use of human growth hormones has been associated with higher rates of soft-tissue oedema, arthralgias and carpal tunnel syndrome. furthermore, dietary supplements advertised as having anabolic, fatreducing and anticatabolic properties, and containing the prohibited growth hormone-releasing peptide-2 (ghrp-2), were detected a few years ago. the presence of such substances may lead to inadvertent doping infringements. while ghrp-2 itself is not specifically barred by the wada for use by athletes, it is a releasing factor that belongs to a prohibited substance group on their list.[7] other newer molecules a selective androgen receptor modulator and agonists of the peroxi some proliferator-activated receptor δ, which produce anabolic effects and enhance endurance, respectively, have been found on the black market.[7] it has also come to the attention of the wada that another substance for increasing endurance, gw501516, has been available for some time on the black market, through the internet and elsewhere. anti-doping authorities have already seen its use by athletes, as there have been a number of positive cases. this developmental drug has not been approved for clinical use anywhere in the world and has been withdrawn from further investigation by pharmaceutical companies due to its serious toxicity profile.[10] identification and determination of prohibited substances while a wide variety of analytical techniques have been used in the past to detect prohibited drugs in biological fluids, rapid improvements in mass spectrometry (ms) have allowed accredited laboratories to develop specific and comprehensive screening methods that are able to detect amounts of drugs and/or their metabolites in quantities as low as 1 mg/l in urine.[4] over many years, gas chromatography (gc) has proven itself in laboratories to be a useful technique for separating and identifying individual components in mixtures of chemical compounds on various chromatographic columns in terms of their retention characteristics (relative to an internal standard compound), as well as for quantifying them. a variety of detectors, e.g. flame ionisation detectors, thermal conductivity detectors and electron capture detectors have been used for this purpose. however, for the successful application of this technique, it is a prerequisite that for compounds to be separated, they are volatile, usually after the necessary derivatisation steps. samples may also have to be hydrolysed to release steroid metabolites from their glucuronic acid conjugates, usually by means of the enzyme β2-glucuronidase, which may result in the generation of related steroidal compounds or incomplete deconjugation. for the purpose of volatilisation, the mixtures to be analysed are often trimethylsilylated (tms) prior to injection onto gc columns. the more volatile tms ethers of the individual components are then distributed between gaseous and solid phases, separated and detected. by feeding gaseous effluents from a gc into an ms, further improvement in identification and quantitation of compounds in mixtures can be expected. however, this technique of gc/ms is not so eminently suitable for routine clinical analysis, but has better applications as a screening tool of prohibited compounds in dietary supplements or urinary metabolites because of the high labour intensiveness, high cost and relatively poor sensitivity. the poor sensitivity is of relevance when samples are analysed for compounds which have low thermal stabilities, e.g. steroids such as trenbolone and gestrinone.[4] in recent years, another chromatographic tool, i.e. liquid chromatography (lc) coupled to ultraviolet or diode-array detectors, has become increasingly important in drug-assaying laboratories. however, similar to gc, this method is not sensitive enough to detect trace levels of compounds and is not well suited for the identification of new substances with unknown chemical and physical properties. coupled with ms, it provides specificity, precision and high sensitivity, allowing the detection of very low quantities of polar and non-polar compounds, a requirement being that the methodology be extensively validated. lc/ms has high throughput capabilities, requires small sample volumes, minimal sample preparation and thermal stability is usually not a factor. furthermore, if required, a number of components can be identified and quantified in a single analysis within the dynamic calibration range of the instrumentation, which can span four orders of magnitude. additionally, because of the absence of hydrolysis or derivatisation steps, lc/ms can be used to measure concentration ratios for steroids between conjugated and free forms, thereby lowering the risk of false positive or misleading outcomes. the use of ultra-high performance lc has further improved chromatographic resolution, thereby lowering the possibility of missing potentially important co-eluting analytes, and critical pairs of isomers may be separated and detected. coupled with high acquisition rate mass analysers such as triple quadrupole ms in tandem with lc/ms(/ms), exceptionally powerful techniques have 90 sajsm vol. 26 no. 3 2014 evolved in the detection of steroids with marginal gc properties, for example. [1113] methodologies such as these have enabled the identification of characteristic product ions of common steroid structures and nuclei.[11] these powerful analytical tools provide a means of detecting a wide variety of unknown steroids based on common chemical structural properties, new metabolites, as well as new designer steroids (likely to be added to dietary supplements) made to circumvent anti-doping controls. conclusion dietary supplement use among athletes to enhance performance is proliferating as more individuals strive to obtain a chemical competitive edge. as a result, the concomitant use of dietary supplements containing performance-enhancing substances that fall in the categories outlined in the current review can also be expected to rise. this is despite ever-increasing, sophisticated analytical methodology techniques being used to assay dietary supplement and urine samples in doping laboratories. the reasons for this include: a variety of these chemical entities, many of them on the prohibited drug list of the wada, are being produced commercially in factories around the world; aggressive marketing strategies are being employed by companies; and these supplements can be easily ordered, for example via the internet. it can also be anticipated that there will be an increase in the number of supplements containing designer steroids and other newer molecules. chromatographic techniques combined with ms, leading to identification of molecular fragments and product ions, will assist in determining these substances. to prevent accidental doping, information regarding dietary supplements must be provided to athletes, coaches and sports doctors at all levels of competition. in south africa, this situation is complicated by the fact that the system of acts and bills lacks specificity regarding nutritional supplements, including the listing of prohibited substances on package labels.[14,15] the risks of accidental doping via dietary supplement ingestion can be minimised by using safe products listed on databases, e.g. such as those available in the netherlands and germany.[5] finally, athletes must be reminded that if they test positive for a prohibited substance not disclosed on the package label of a supplement, it would constitute a doping violation, with all the consequences thereof. references 1. van der bijl p. dietary supplements containing prohibited substances: a review (part 1). south african journal of sports medicine 2014;26(2):59-61. [http://dx.doi. org/10.7196/sajsm.552] 2. geyer h, parr mk, mareck u, reinhart u, schrader y, schänzer w. analysis of nonhormonal dietary supplements for anabolic-androgenic steroids: results of an international study. int j sports med 2004;25(2):124-129. [http://dx.doi.org/10.1055/s-2004-819955] 3. king ds, baskerville r, hellsten y, et al. a z of dietary supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance, part 34. br j sports med 2012;46(9):689-690. [http//dx.doi.org/10.1136/bjsports-2012-091314] 4. gosetti f, mazzucco e, gennaro mc, marengo e. ultra high performance liquid chromatography tandem mass spectrometry determination and profiling of prohibited steroids in human biological matrices: a review. j chromatogr b analyt technol biomed life sci 2013;927:22-36. [http://dx.doi.org/10.1016/j.jchromb.2012.12.003] 5. geyer h, parr mk, koehler k, mareck u, schänzer w, thevis m. dietary supplements cross-contaminated and faked with doping substances. j mass spectrom 2008;43(7):892-902. [http:dx.doi.org/10.1002/jms.1452] 6. ambrose p. drug use in sports: a veritable arena for pharmacists. j am pharm assoc 2004:44(4):501-514. 7. geyer h, braun h, burke lm, stear sj, castell lm. a-z of dietary supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance, part 22. br j sports med 2011;45(9):752-754. [http://dx. doi.org/10.1136/bjsports-2011-090180] 8. parr mk, koehler k, geyer h, guddat s, schänzer w. clenbuterol marketed as dietary supplement. biomed chromatogr 2008;22(3):298-300. [http://dx.doi.org/10.1002/ bmc.928] 9. liu h, bravata dm, olkin i, et al. systematic review: the effects of growth hormone on athletic performance. ann intern med 2008;148(10):747-758. 10. wada issues alert on gw501516. http://playtrue.wada-ama.org/news/wada-issuesalert-on-gw501516/ (accessed 15 may 2014). 11. catlin dh,  sekera mh,  ahrens bd,  starcevic b, chang yc, hatton ck. tetrahydrogestrinone: discovery, synthesis, and detection in urine. rapid commun mass spectrom 2004;18(12):1245-1249. [http://dx.doi.org/10.1002/rcm.1495] 12. thevis m, geyer h, mareck u, schänzer w. screening for unknown synthetic steroids in human urine by liquid chromatography-tandem mass spectrometry. j mass spectrom 2005;40(7):955-962. [http://dx.doi.org/10.1002/jms.873] 13. pozo oj, van eenoo p, deventer k, delbeke ft. development and validation of a qualitative screening method for the detection of exogenous anabolic steroids in urine by liquid chromatography-tandem mass spectrometry. anal bioanal chem 2007;389(4):1209-1224. [http://dx.doi.org/10.1007/s00216-007-1530-6] 14. gabriels g, lambert m, smith p. information on nutritional supplement labels: time for legislation? s afr j clin nutr 2012;25(1):22-26. 15. gabriels g, lambert m, smith p, hiss d. will the new consumer protection act prevent harm to nutritional supplement users? s afr med j 2011;101(8):543-545. panel discussion 1 sajsm vol. 34 no. 1 2022 creative commons attribution 4.0 (cc by 4.0) international license blood flow restriction training in south africa – a panel discussion rw evans,1 phd; j ganda,2 mbchb, mphil sem; l van schalkwyk,3 bsc physiotherapy; dl fabricius,4 msc sem; m cornelissen,5 ba hons biokinetics 1 enable centre, cape town, south africa 2 sports rehab centre, cape town, south africa 3 western province & stormers rugby, cape town, south africa 4 lambert sports clinic, london, united kingdom 5 biokinetics association of south africa, centurion, south africa. corresponding author: rw evans (robertevanssa@gmail.com) in july 2022, the health professions council of south africa (hpcsa) was informed that clinicians in south africa were being trained to use blood flow restriction (bfr) as a treatment modality. the technique manipulates blood flow and therefore there are some associated ethical and safety concerns. the hpcsa was unable to support the use of bfr due to a lack of submitted information and evidence that allowed its professional board for physiotherapy, podiatry and biokinetics (ppb) to make an informed decision. as a result, the hpcsa was tasked to determine if (1) bfr is a valid treatment modality, and (2) whether it fits within the scope of practice of physiotherapists and biokineticists in south africa. at the time of the publication of this roundtable discussion, bfr training had not been incorporated into the toolbox of treatment modalities available to physiotherapists and biokineticists in south africa. bfr, although practised since the 1970s, was first published in a 1997 study.[1,2] in the subsequent 25 years, a relatively rich body of evidence has been published supporting its use. despite this, bfr remains a novel technique in south africa, with little known about how it is used amongst health professionals and what beliefs are held regarding its safety and efficacy. to prepare for its formal submission to the hpcsa and to gain better insight into the use and perception of bfr in south africa, an expert panel of medical professionals was asked a series of questions. the following panellists were invited to participate: dr janesh ganda, (sports physician and team doctor of the south african 7s rugby team), lize van schalkwyk, (physiotherapist and head of physiotherapy at western province rugby and the stormers rugby), and david fabricius, (biokineticist and head of performance and wellness at the lambert sports clinic, london). dr robert evans (biokineticist and clinical director at the enable centre) was the panel facilitator. before the various questions were explored, there was a discussion about the definition of bfr to ensure that all panellists were referring to the same techniques and protocols. following this discussion, the working definition was; bfr or occlusion training involves the use of a cuff or tourniquet system placed around the proximal end of a limb and inflated/tightened to a specific pressure (studies range from 110 to 240 mmhg with pneumatic cuffs). through this pressure, the venous outflow is slowed, whilst arterial flow is maintained – resulting in an anaerobic environment.[1] following agreement about the definition, panellists were asked a series of questions. do you consider bfr training safe? janesh ganda: yes. traditionally, when attempting to improve muscle mass and strength, high-intensity resistance training loads of 75%-80% of one repetition maximum (1rm) are often indicated.[3] using bfr, one can get similar hypertrophic and strength responses at 10%-20% of 1rm. this makes bfr training safe and valuable in the rehabilitation of patients who may not be able to perform high-load resistance training (hlrt), such as patients undergoing rehabilitation and recovering athletes. bfr enables practitioners to reduce the load on the joint while still placing the limb under appropriate strain.[3] lize van schalkwyk: yes, i believe it is a safe training modality to use. in a review article, the authors found no significant higher risk in cardiovascular response, venous thromboembolism (vte), or muscle damage.[4] the principle of bfr training is to work at a resistance level of 20%-40% of 1rm, which will cause less strain on the joints and soft tissue than hl-rt. the percentage of blood flow restriction will be 40%– 80% of arterial occlusion pressure (aop), also known as limb occlusion pressure (lop), and therefore not causing complete restriction of blood flow. in our clinical setting, we work with elite sportsmen who undergo annual medical screening, including cardiac screening. our patient population consists of healthy, young athletes. the decision to use bfr training for an injured player is based upon enabling the athlete to start with some form of muscle stimulus and loading at an earlier background: blood flow restriction (bfr) training uses a cuff to partially occlude venous blood flow and improve musculoskeletal training outcomes. over the past 25 years, numerous studies have demonstrated its relative safety and efficacy. objectives: blood flow restriction training is under review by the health professions council of south africa due to safety and ethical concerns. the objective of this roundtable discussion is to gain better insight into the current use and perception of blood flow restriction training in south africa. formation of panel: the expert panel had experience with the use of bfr training and included one representative from each of the following professions, namely, sports medicine, physiotherapy and biokinetics. discussion: the panellists provided their unique perspectives on bfr training, whilst reaching a relative consensus on its safety, screening, efficacy, and appropriate use. agreement on appropriate loading and occlusion pressure protocols during different phases of rehabilitation was less clear. conclusion: although bfr is a safe and effective modality, the development of evidence-based protocols among different health professionals in south africa is required to ensure good clinical practice. keywords: bfr, occlusion training, hpcsa, biokinetics, physiotherapy s afr j sports med 2022;34:1-4. doi: 10.17159/2078-516x/2022/v34i1a14796 about:blank http://dx.doi.org/10.17159/2078-516x/2022/v34i1a14796 https://orcid.org/0000-0002-8724-4838 https://orcid.org/0000-0002-9177-9149 https://orcid.org/0000-0003-0989-2052 https://orcid.org/0000-0001-7306-3131 panel discussion sajsm vol. 34 no. 1 2022 2 stage than what is possible with hl-rt. this should therefore also be safe to use in the general population. david fabricius: yes, bfr with correct implementation and supervision presents no greater risk than traditional modes of exercise, with a low risk of possible adverse responses or concerns of disturbed haemodynamic and ischaemia reperfusion injury. bfr requires an individualised approach when selecting cuff pressure for both safety and effectiveness. case study reports of adverse responses to acute sessions of bfr, regarding rhabdomyolysis and delayed onset muscle soreness (doms), are independent of bfr and include individuals unaccustomed to exercise.[5] injuries resulting from bfr seem rare and risks of adverse events may be exacerbated in clinical populations (e.g. patients with established cardiovascular disease, hypertension, diabetes mellitus, and chronic kidney disease). current recommendations suggest 40%–80% of lop when conducting bfr in clinical populations. lower pressures may provide less risk without the need for higher pressure. establishing lop is quick and easy to perform with a handheld doppler and may minimise any cardiovascular risk from bfr during exercise, alongside pre-exercise screening. what precautions should be taken? janesh ganda: a pre-participation health screening should be performed, or medical clearance should be attained before initiating bfr. anatomically, one should be wary of skin, muscle, vessel, and nerve injuries. the main side effects observed by queiros et al. [6] were tingling (71%), doms (56%) and excessive pain during exercise (45%). rhabdomyolysis, fainting, and subcutaneous haemorrhage were reported infrequently (1.9%, 3.8%, 4.8% respectively). the main contraindications for the use of the technique are a history of thrombosis and any cardiovascular disorder. several other contraindications are mostly related to the risk of thrombosis secondary to venous stasis. lize van schalkwyk: the precautions will have to be standardised in the same manner as applies to all other treatment modalities. it will be important to do a thorough musculoskeletal (msk) and injury assessment of the patient to determine if and at what stage bfr training will be indicated. the normal precautions for the specific injury will apply. i suggest a standardised health screening that will include any previous pulmonary embolism (pe) or deep vein thrombosis (dvt), family history of pe or dvt, obesity, hypertension, medication, and history of syncope. the practitioner must explain to the patient what bfr will entail, what it feels like, possible lasting sensation changes in post-training, etc. it is important to use the correct pressure for the cuff width and not to leave the patient unattended whilst undergoing bfr training. it is also advisable to ensure there is an emergency action plan in place at the facility in the extreme event of an adverse reaction. this will apply in normal circumstances and not only for bfr training. david fabricius: to ensure that bfr is properly used, and there are efficacy endpoints, it is recommended to use a questionnaire for risk stratification involving a review of the patient’s medical history, and signs and symptoms indicative of any underlying pathology. bfr pre-participation screening theoretically can reduce risks by excluding people with comorbidities or medically complex histories that could unnecessarily heighten the intraand/or post-exercise occurrence of adverse events. nascimento et al. proposed a risk stratification tool as a framework to allow clinicians to use their knowledge, skills, and expertise to assess and manage any risks related to the delivery of an appropriate bfr exercise programme.[7] do you consider bfr to be an effective training technique? janesh ganda: bfr has far-reaching effects on multiple body systems, including cardiovascular, pulmonary, vascular, msk, and the endocrine system. it appears that the greatest benefit of using bfr is its ability to safely augment exercise intensity in both comorbid and healthy individuals. bond et al.[8] showed successful outcomes in the rehabilitation setting in postsurgical patients (osteochondral fractures, achilles tendon ruptures, knee arthroscopy); however, caution should be exercised in these patients due to their tendency to also have venous thromboembolism (vte). an additional benefit of bfr is associated with improving or maintaining vo2 max. this is valuable in populations who are unable to exercise at intensities high enough to improve or maintain aerobic capacity.[9] lize van schalkwyk: yes, i believe bfr training is effective and beneficial. in a systematic review, the authors found changes in both muscle strength and hypertrophy.[3] we started using this technique about four years ago. some of our patients had underlying joint injuries, i.e. osteochondral knee injuries, patellafemoral dysfunction, etc. and were not able to cope with the normal running load required within hl-rt programmes. these athletes started using bfr during aerobic and/or resistance training as an activation before a field session, and we also adapted their gym programmes to incorporate bfr. although we did not do any formal research studies, we found strength gains and better functional movement in these athletes. david fabricius: yes, training with bfr can present beneficial adaptations to skeletal muscle strength, muscle mass, and performance in different population groups when combined with strength and aerobic training. low-load resistance training (ll-rt) with bfr (20%–30% of 1rm) may be superior at increasing muscle strength and mass to that of ll-rt alone, and comparable to hl-rt without bfr (70%– 80% of 1rm) in people with msk conditions. if increasing strength is the aim of the training and heavy loads cannot be tolerated or are contraindicated, then ll-rt with bfr training is an evidence-based option. in addition to resistance training, bfr has been shown to improve muscle performance and aerobic capacity during aerobic exercise (~45% vo2max) and can be performed passively to prevent muscle atrophy and improve physical function. in what situations may it be beneficial? janesh ganda: bfr has widespread applications, including being incorporated into training for high-level athletes or post panel discussion 3 sajsm vol. 34 no. 1 2022 operative rehabilitation for patients with limited activity and the ability to undertake weight-bearing exercises. this includes patients who have suffered spinal cord injuries. given the ability of bfr to stimulate gains at a submaximal load, athletes can often incorporate this sort of treatment at the end of their workout to achieve greater strength gains. bfr training can lead to significant improvements in muscle strength, markers of sports performance and muscle size.[1] lize van schalkwyk: we use bfr on all patients that have undergone lower limb surgery and must be immobilised for a period, who cannot weight-bear post-surgery, and when loaded gym work is still contraindicated. we combine it with neuromuscular electrical stimulation during open chain exercises – either focusing on the quadriceps, hamstrings, or gastrocnemius muscles. examples of injuries where we have used bfr include, anterior cruciate ligament (acl) reconstruction, microfracture surgery for femoral and patella osteochondral lesions, achilles rupture and syndesmosis repair. we have recently started using bfr on the upper limb after shoulder surgery. as mentioned previously, we find bfr beneficial for athletes who are unable to cope with standard training loads. david fabricius: as a novel method of exercise training, bfr could be used as a safe alternative to hl-rt with broad applications in clinical populations, the elderly, rehabilitation after injury or post-surgery and healthy athletic populations.[1] multiple benefits exist beyond that of muscular growth, including improvement in muscular endurance, cardiovascular fitness, pain, and bone density. it is well documented that muscle hypertrophy and strength adaptations with bfr are significantly greater than those achieved with ll-rt alone. such adaptations have been observed after only one to three weeks. how and where should bfr be used by health professionals in south africa? janesh ganda: the implementation of bfr training requires a bfr device, which can range from an inexpensive “wrap”, a regular pneumatic manual cuff, or an automated cuff. the gold standard to determine cuff pressure is the use of aop which requires the use of doppler ultrasound to determine the pressure required to cease blood flow to the limb. percentage of resting systolic blood pressure (sbp) can also be used. recommendations include 80% resting sbp for continuous bfr training and 130% for intermittent training. currently prescribed protocols for resistance training include an intensity of 20%-30% of 1rm, short intervals, and a volume of up to 75 repetitions, which can be divided into four sets of 30/15/15/15 repetitions respectively.[4] little equipment is required for the implementation of bfr training. it should therefore be carried out in a rehabilitation or clinical practice setting with the treating practitioners having at least a basic knowledge of physiology and anatomy to ensure patients do not have any contraindications. lize van schalkwyk: bfr training is currently not widely used in south africa. i have not come across peers that use it in their clinical environment. i believe there is scope within the physiotherapy regimes to use passive bfr for patients that are immobilised for long periods of time due to paralysis, illness, surgery, etc. bfr aerobic and resistance exercise can also be used to prevent muscle atrophy and maintain function both preand post-surgery or post-injury when higher load training is still contraindicated. bfr must be used under supervision, with the principles and possible side effects explained to the patient. the therapist and patient should sign a consent form, as is the case with most treatment modalities. david fabricius: in the south african context, the physical rehabilitation process is often shared by practitioners from different disciplines. the decision about which practitioner is best suited depends on their scope of practice and the timeframe of the injury (figure 1). bfr is not a stand-alone modality to improve outcomes for a specific diagnosis or condition, but rather a useful adjunct. the simple addition of a bfr cuff to ll-rt under the supervision of a competent professional will lead to achieving superior results in muscle adaptations or functional capability. the suggested multidisciplinary, staged approach in figure 1 corroborates the evidence-based progressive model of loenneke et al. [10] this approach consists of four phases: (1) passive bfr; (2) bfr with aerobic training; (3) bfr with ll-rt; and (4) bfr with lowload ll-rt in combination with traditional hl-rt.[11] these phases can be integrated into the stages of a traditional msk rehabilitation programme. which health profession’s scope of practice does bfr fall within? janesh ganda: bfr training should fall within the scope of practice of physiotherapists and biokineticists in south africa. this is due to their role in rehabilitation following acute injuries and the knowledge of physiology and anatomy ensuring that patients safely meet the criteria for bfr training. lize van schalkwyk: there must be a distinction made between using bfr as a modality for an injured person versus using it for the general population as a training modality. in the medical environment, the referring doctor can prescribe fig. 1. progressive multidisciplinary bfr rehabilitation model [11] panel discussion sajsm vol. 34 no. 1 2022 4 bfr as part of the treatment protocol. if a physiotherapist is treating the patient, he/she should inform the referring doctor of the intent to use the modality and clarify any potential risk factors with the doctor. the same will apply to a biokineticist who is treating a patient that was referred to them. there must be a standardised protocol i.e. consent, risk factors, contraindications, etc. in our facility, it will be a joint decision between the physiotherapist and the strength and conditioning trainers. david fabricius: the doctor and physiotherapist are entitled to screen and prescribe both the passive and active applications of bfr within rehabilitation. both the doctor and physiotherapist are likely to address the early assessment and treatment within both inand out-patient capacities. biokineticists can screen and utilise bfr where active movement is indicated. in reference to figure 1, biokineticists can start treatment from stage two onwards (bfr aerobic exercise) and can facilitate rehabilitation or training up to stage four (traditional heavy loading). physiotherapists can complete the entire rehabilitation process. however, within any multidisciplinary setting, each practitioner plays a pivotal and collaborative role in the envisioned rehabilitation process. what do you envision the future of bfr training to be? janesh ganda: the ease of application and benefits of bfr training should make this modality of training more popular, specifically in athletes recovering from injury, post-surgical patients, and the elderly. the msk benefits (increase in muscle size and strength) which can be achieved at a fraction of the 1rm reduce the loading on the joint while still achieving the benefits of resistance training. lize van schalkwyk: bfr is currently not widely used in the clinical environment. there is a large body of research published that will help to standardise protocols. numerous studies use different cuff sizes, different pressures, different loads, and rest periods, but they all appear to achieve positive results in increasing muscle strength and hypertrophy. as more clinicians start using bfr, there will be better study outcomes to support its benefits. david fabricius: within the available literature, great strides have been made in utilising bfr in the treatment areas of neurological conditions, msk conditions and physical performance enhancement in athletes. as understanding grows behind the mechanisms and physiology of bfr, this field of interest will broaden but give way to more specific protocols and guidelines of treatment. conclusion this roundtable discussion demonstrates relative consensus on numerous fundamental elements of bfr, including its safety, screening, efficacy and appropriate use amongst health professionals in south africa. what is less clear are the relative loading and occlusion pressure protocols in the different phases of rehabilitation. bfr is a relatively new modality and detailed knowledge of its application is lacking. it follows that practitioners should be focused on their duty of care to screen and prescribe bfr effectively and safely. standardised training and the development of evidence-based protocols across different health professionals are required to ensure good clinical practice. the rapid dissemination of such skills to our health professionals in south africa will provide a novel and effective tool which may contribute to bridging the acute and longer-term rehabilitation of numerous patients. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: rwe: conceptualisation, facilitator, writing and editing of article. jg, lvs and dlf: served as an expert panellist and editing of article. mc: conceptualisation and editing of article. references 1. wortman rj, brown sm, savage-elliott i, et al. blood flow restriction training for athletes: a systematic review. am j sports med 2021; 49(7):1938–1944. [doi: 10.1177/0363546520964454] [pmid: 33196300] 2. shinohara m, kouzaki m, yoshihisa t, et al. efficacy of tourniquet ischemia for strength training with low resistance. eur j appl physiol occup physiol 1997; 77(1–2):189–191. [doi: 10.1007/s004210050319] [pmid: 9459541] 3. slysz j, stultz j, burr jf. the efficacy of blood flow restricted exercise: a systematic review & meta-analysis. j sci med sport 2016; 19(8):669–675. [doi: 10.1016/j.jsams.2015.09.005] [pmid: 26463594] 4. patterson sd, hughes l, warmington s, et al. blood flow restriction exercise: considerations of methodology, application, and safety. front physiol 2019; 10:533. [doi: 10.3389/fphys.2019.00533. ecollection 2019] [pmid: 31156448] 5. patterson sd, brandner cr. the role of blood flow restriction training for applied practitioners: a questionnaire-based survey. j sports sci 2018; 36(2):123-130. [doi: 10.1080/02640414.2017.1284341] [pmid: 28143359] 6. de queiros vs, dantas m, neto gr, et al. application and side effects of blood flow restriction technique: a cross-sectional questionnaire survey of professionals. medicine (baltimore) 2021; 100(18):e25794. [doi: 10.1097/md.0000000000025794] [pmid: 33950976] 7. nascimento d da c, rolnick n, neto iv de s, et al. a useful blood flow restriction training risk stratification for exercise and rehabilitation. front physiol 2022; 13: 808622. [doi: 10.3389/fphys.2022.808622] [pmid: 35360229] 8. bond cw, hackney kj, brown sl, et al. blood flow restriction resistance exercise as a rehabilitation modality following orthopaedic surgery: a review of venous thromboembolism risk. j orthop sport phys ther 2019; 49(1):17–27. [doi: 10.2519/jospt.2019.8375] [pmid: 30208794] 9. mendonca gv, vaz jr, pezarat-correia p, et al. effects of walking with blood flow restriction on excess post-exercise oxygen consumption. int j sports med 2015; 36(3): e11–e18. [doi: 10.1055/s-0034-1395508] [pmid: 25665001] 10. loenneke jp, abe t, wilson jm, et al. blood flow restriction: an evidence based progressive model (review). acta physiol hung 2012; 99(3):235–250. [doi: 10.1556/aphysiol.99.2012.3.1] [pmid: 22982712] 11. marais b, klaassen r. progressive multi-professional bfr rehabilitation model. in: an introduction to blood flow restriction therapy: standards of care and good clinical practice for biokineticists. biokinetics association of south africa. centurion, south africa; 2022. p. 13. sajsm vol. 28 no. 2 2016 39 original research physiological responses of batsmen during a simulated one day international century l pote,1 msc; cj christie,1 phd 1 department of human kinetics and ergonomics, rhodes university, grahamstown, south africa corresponding author: l pote (g06p1630@campus.ru.ac.za) background: there is a limited amount of literature on the physiological cost of batting. of the studies that have been completed, most have used protocols that are of short duration and high intensity, and it has been questioned whether this represents actual game play. furthermore, it is difficult to st udy sports such as cricket due to the intermittent nature of the game. objective: to determine the physiological responses of batsmen during a simulated one day international century. methods: seventeen male batsmen from the rhodes university cricket club performed a simulated batting work bout known as the batex© protocol. the protocol consisted of six, five overs stages, each lasting 21 minutes. three of the stages (stages one, three and five) were low-intensity stages and the other three (stages two, four and six) were high-intensity stages. during the work bout selected physiological responses were recorded.. results: heart rate (124±15-159±14 beats.min-1), oxygen uptake (29.3±6.1-43.4±6.3 ml.kg-1.min-1), energy expenditure (48.1±9.2109.2±10.5 kj.min-1) and core temperature (37.7±0.3-38.7±0.4 oc) responses all increased significantly (p<0.05) between stage one and stage six. the respiratory exchange ratio decreased significantly (p<0.05) between stages one and six (0.90±0.190.89±0.37). conclusions: batting is more physically demanding than originally thought, and as a result training programmes should concentrate on simulating real match play situations to improve performance and reduce the risk of injury. keywords: cricket, energy expenditure, heart s afr j sports med 2016;28(2):39-42. doi:10.17159/2078-516x/2016/v28i2a163 the game of cricket has changed substantially over the last century, with the first form of the game, five day test matches, evolving into one day internationals (odi, 50 over games) and twenty20 cricket (20 over games).[1] more specifically, in odis, more runs are scored per innings and by individual batsmen. furthermore, a batsman scoring a century runs 40 singles, eight twos, three threes and hits an average of seven fours and two sixes after spending approximately 136 minutes at the crease.[2,3] thus it is evident that both the physical and psychological load placed on the players is increasing. however, these demands have not received much attention, most likely because the game is intermittent in nature and therefore difficult to study.[2,4] the first study that quantified the physical cost associated with cricket was during the 1953 ashes series.[5] this study concluded that the average cricketer expended approximately 650 kj.h-1, and that cricket was a physically undemanding sport. however, this study focused specifically on test matches, and the demands of the game have changed substantially since 1953. it was 38 years later when it was reported that during an odi game, batsmen had sweat rates, heart rates and rectal temperatures of up to 6 l.h-1, 120 beats.min-1 and 38.5 oc respectively.[6] this led to the conclusion that cricket was more physically demanding than previously thought, a statement that was further validated by noakes and durandt[3] in 2000. since then other studies have been conducted in these authors’ laboratory. king,[7] in 2002, reported a mean heart rate response of 138 beats.min-1 and a peak response of 168 beats.min-1, as well as sweat rates of 0.93 l.h-1. christie et al.,[4] in 2008, showed a mean heart rate of 145 beats.min-1, oxygen uptake of 26.7 ml.kg-1.min-1, a respiratory exchange ratio of 1.05 and an energy cost of 2536 kj.h-1. other measures recorded during this study included breathing frequency (31.2 breaths.min-1), tidal volume (2.2 l) and minute ventilation (65.1 l.min-1). the last study conducted in these authors’ laboratory showed responses between 140-168 beats.min-1, 24.928.1 ml.kg-1.min-1 and 9.7-11.6 for heart rate, oxygen uptake and energy expenditure respectively.[8] these studies used short duration (seven overs), high-intensity (maximal sprints) protocols, and it has been questioned whether this is representative of actual match play. of note, however, is that these responses were quite accurate when comparisons are made to real game play where heart rate responses between 139-154 beats.min-1 during odi matches and 149-167 beats.min-1 during t20 matches have been reported.[9,10] this is further validated by the mean heart rate (164±12 beats.min-1) recorded by vickery et al.,[11] during a simulated, eight over, match situation according to these authors, the only long duration, laboratorybased protocol has been performed by houghton et al.,[12] where a simulated century batting work bout, known as the batex© protocol, was used. the protocol consisted of six, five over stages (21 min each) that represented certain phases of play. the study showed a mean heart rate, tympanic temperature and sweat rate of 130 beats.min-1, 35.9 oc and 0.9 l.h-1. however, although this investigation used a long duration protocol, the main aim was not the physiological cost of batting and so the responses measured were limited and crude. therefore t he m ain a im o f t his p resent s tudy w as t o e xamine m ore detailed physiological responses of players batting for extended periods of play using the batex© protocol, previously validated by houghton et al.[12] methods this repeated measures study design utilised one condition and tested responses over time. ethical approval was granted by the department of human kinetics and ergonomics ethical standards committee for research involving human participants (rhodes university, grahamstown, south africa) and all participants provided written informed consent. the s ample c onsisted o f 1 7 m ale c ricket b atsmen ( mean ± s .d. for age, stature, mass, body mass index and body fat percentage were 22.5±2.3 years; 181.6±5.6 cm; 81.7±9.9 kg; 24.9 ±2.8 kg.(m2)-1 and 12.9±2.4% respectively) playing for the rhodes university cricket club. mailto:g06p1630%40campus.ru.ac.za?subject= http://dx.doi.org/10.17159/2078-516x/2016/v28i2a163 40 sajsm vol. 28 no. 2 2016 two testing sessions were required. the first testing session was used to collect basic anthropometric and demographic data and to familiarise the players with the equipment and the simulated century protocol (batex© protocol as described by houghton et al.[12]). the batex© protocol was used as this is the only century protocol that has been validated. equipment included a portable online metabolic system, the k4b2 (cosmed®, rome), a polar® heart rate monitor (kempele, finland) and a coretemp® (hqinc., united states of america) monitoring system. these were used to measure oxygen consumption (vo2), respiratory exchange ratio (rer), heart rate (hr) and core temperature responses over the duration of the protocol. before each testing session, the k4b2 was calibrated using a hans rudolph 5530 3-l syringe for volumetric calibration, a gas mixture (16.10% oxygen, 4.90% carbon dioxide and 79.00% nitrogen) for the sensors as well as a room air calibration. briefly, the protocol consisted of six, five over stages (21 min each) and each stage matched a specific phase of play, where batsmen were encouraged to bat with the mindset typical of that phase. for example, stages one, three and five were low-intensity stages, where players ran at a self-selected cruise pace whereas stages two, four and six were high-intensity stages, where players were required to sprint the runs between the wickets (17.68 m, the length of a cricket pitch). furthermore, there was a 35 s break between balls and a 75 s break to simulate the bowler walking back to their mark and the change in over. during familiarisation, players were also instructed not to consume alcohol or partake in any physical activity 24 hours prior to testing and to bring cricket kit (pads, gloves, thigh pads and box) to the testing session. at the end of the first session each player was given a core body temperature pill to swallow two hours before the second session, to allow it to enter the digestive tract prior to the experimental session. the second testing session (5-7 days after familiarisation) was completed at the high performance centre, kingswood college in grahamstown, south africa. on arrival at the centre, players performed a cricketspecific, dynamic warm-up (as described by houghton et al.[12]) to minimise the risk of injury, after which they padded up in cricket kit and were fitted with the equipment to perform the batex© century protocol. balls were delivered (at 105 km.h-1) using a bowling machine (brell express bowling machine, flicx, south africa), on the batsman’s front foot, on the offside. the batex© audio track notified the researcher when to release the next ball. the audio track was also used to notify the batsmen of how many shuttle runs (17.68 m, the length of a cricket pitch) to complete in the upcoming over. at the halfway point of the protocol, players were given an energade sports energy drink (645 kj; 39 g cho) to consume. after the experimental session was completed, the equipment was removed from the players and they were required to partake in a cool-down session (approximately ten minutes), which included a jog and more cricket-specific stretches. statistical analysis all statistical analyses were performed using statistica 10 software. descriptive measures of physiological, performance and perceptual data included mean values and standard deviations. the level of significance was set at p<0.05. effect size characterised the magnitude of difference between the various stages. the criteria for interpreting effect sizes were: <0.2 trivial, 0.2-0.6 small, 0.6-1.2 moderate, 1.2-2.0 large and >2.0 very large.[13] a one-way analysis of variance was used to compare differences between stages at different intensity levels over time. tukey’s post hoc analyses identified specific areas of differences. results significant differences were observed for all measures between stage one and stage 6 (table 1). heart rate responses increased significantly (p<0.05) from stage one to stage six (124 ± 15 to 159±14 beats.min-1) with a mean heart rate of 144 (±15) beats.min-1. a large effect size (es) was observed between stages one and two (es=1.60) and a moderate effect size between stages one and five (es=0.55). mean vo2 was 36.7 (±6.5) ml.kg-1.min-1, with the low intensity stages, expectedly, eliciting lower responses compared to the high intensity stages. large effect sizes were also observed between the different intensity stages (stage one-two es=1.45, stage three-four es=1.62, stage five-six es=1.24 respectively). rer decreased significantly (p<0.05) from 0.90±0.19 until the drinks break (0.92±0.19). after the drinks break, responses increased significantly (p<0.05) (stage four) and then decreased to the lowest mean response (0.84±0.17) during stage five. at the end of stage six rer was 0.89±0.37. table 1. physiological responses of batsmen (n=17) during the six stages of the batting protocol (mean ± s.d.) stage 1 stage 2 stage 3 stage 4 stage 5 stage 6 mean hr (beats.min-1) 124 (15) 148 (15) 136 (15) 150 (14) 144 (15) 159 (14) 144 (15) vo2 (ml.kg-1.min-1) 29.3 (6.1) 38.7 (7.2) 31.3 (5.5) 41.8 (6.8) 35.4 (6.4) 43.4 (6.3) 36.7 (6.5) ee (kj.min-1) 48.1 (9.2) 63.6 (10.9) 50.6 (9.2) 68.2 (9.2) 56.9 (10.5) 70.7 (10.5) 59.8 (9.6) tc (oc) 37.7 (0.3) 38.2 (0.2) 38.4 (0.3) 38.2 (0.8) 38.5 (0.4) 38.7 (0.4) 38.3 (0.4) rer 0.95 (0.19) 0.95 (0.18) 0.86 (0.16) 0.92 (0.19) 0.84 (0.17) 0.89 (0.18) 0.90 (0.18) hr = heart rate; vo2 = oxygen uptake; ee = energy expenditure; tc = core temperature; rer = respiratory exchange ratio. significances and effect sizes are discussed in the text. energy expenditure responses increased significantly (p<0.05) from stage one to stage 6 (48.1 ± 9.2 to 70.7 ± 10.5 kj.min-1). a mean energy expenditure of 59.8 ± 9.6 kj.min-1  was recorded. large magnitude changes were observed between all stages (es = 1.58, 1.32, 1.79, 1.41) except between stages four and five where a moderate change was observed (es = 1.15). significant increases (p<0.05) in core temperature was observed between stage one and stage six (37.7 ± 0.3 to 38.7 ± 0.4 oc). the only large effect size was observed between stages one and two (es = 1.40). mean core temperature was 38.3 ± 0.4 oc. discussion the main finding of this study was that batting for extended periods, such as during the batex© protocol, significantly influences the fatigue profile experienced by a batsmen, sajsm vol. 28 no. 2 2016 41 which is exacerbated by batting in the heat. this was a result of both the intensity and duration of the work bout. responses in this study were similar to those recorded by both king[7] and christie et al.[4] who found mean heart rate responses of 145 and 138 beats.min-1 respectively. both studies used short duration, high-intensity work bouts where batsmen ran a double shuttle every second delivery. this suggests that batsmen regulate intensity of effort dependent on duration so that cardiovascular load remains stable. however, this must be seen within the context of the study designs which did not take into consideration aspects of game, player and competition dynamics to name a few factors which may impact heart rate responses. pote and christie[8] found higher heart rate responses in their study (140-168 beats.min-1) this was to be expected as, although the protocol was short in duration, players were required to sprint every ball, rather than every second ball. in contrast, a longer duration protocol used by houghton et al.[12] reported lower heart rate responses than seen in this study. this can be explained by the calibre of the player. houghton et al.[12] used professional players, while the players in this study were non-professional batsmen, although player ages for both studies were similar. of note, however, is that the responses in this study are comparable to data obtained during real match play even though the players were not exposed to actual game dynamics, such as scoreboard pressure and importance of the match (exhibition vs. world cup match).[9,10] this was not the case though when compared to gore et al.[6], who also looked at real match play data (mean of 144±15 beats.min-1); however, this was to be expected as the game of cricket has changed to a large extent since 1993. an interesting finding was the effect of both duration and intensity on heart rate responses. previous batting studies have shown that duration had no impact on cardiovascular responses.[14] this was not the case in this study as there was a significant (p<0.05) increase in heart rate between stages one and six (124-159 beats.min-1) as well as a significant (p<0.05) increase between stages two and six (148-159 beats.min-1), thus showing the effect of duration on changing physiological responses. mean oxygen consumption (36.7±6.5 ml.kg.min-1) was considerably higher than shown in previous cricketing studies (christie et al.[4]: 26.7 ml.kg.min-1; pote and christie[8]: 26.9 ml.kg. min-1). this could be because those studies used shorter protocols and because in this study, vo2 rose significantly (p<0.05) between stages one and two (29.3-38.7 ml.kg.min-1) and then remained high throughout the rest of the protocol. this indicates that players may not have recovered sufficiently in the low-intensity stages before starting the high-intensity stages. the duration of the protocol and the intensity of the different stages also affected vo2 responses as shown by the large effect sizes (es=1.45, 1.62 and 1.24, between stages one and two, three and four and five and six respectively). mean rer during the protocol (0.90±0.18) was lower than the only other study to report on this response during batting (christie et al.[4]: 1.05), as more carbon dioxide was produced due to the high intensity of the shorter protocol, therefore resulting in an increased rer. at the start of the protocol, players were utilising mainly carbohydrates as an energy source, but as the protocol approached the drinks break there was a shift in substrate utilisation, due to the increase in exercise duration, indicating reduced reliance on carbohydrates.[15] the slight rise in rer after the drinks break could be attributed to the ingestion of an energade sports energy drink (645 kj; 39 g cho), which could have resulted in higher carbohydrate utilisation from the ingested glucose. rer then decreased for the remainder of the protocol indicating a greater reliance on fats as an energy source, which was to be expected. important to acknowledge, however, is that rer during intense exercise may not be a reliable indicator of substrate use, although it could be argued that in this study, over time, intensity of effort was moderate. the mean energy cost (59.8±9.6 kj.min-1) observed in this study was substantially higher than that proposed by fletcher[5] in 1955. however, this must be seen within the context of the changing nature of the game, specifically with respect to higher batting scores and individual runs scored per innings. when compared to other cricketing studies (christie et al.[4]: 42.3 kj.min-1; pote and christie[8]: 46.4 kj.min-1), the responses shown in this study are higher. this was to be expected as batsmen batted for a longer time, ran a higher number of runs and performed the protocol at different intensities. this emphasises the importance of measuring the impact that prolonged batting has on players. an understanding of these factors will influence the design of training programmes which has important performance implications for these players. batsmen were also required to ‘touch and turn’ at the non-strikers end when running a single as if looking for another run. this may have affected the energy cost recorded, as research has shown that the deceleration, turning at the crease and reacceleration have an impact on energy cost.[8] furthermore, because other physiological responses were not affected by this occurrence, it means that this extra energy cost may be the result of changes in the player’s muscle force, producing capabilities required when turning for another run.[8] mean core temperature (38.3±0.4 oc) was higher than in previous cricket studies, but the previous studies used tympanic, skin, rectal and forehead temperature. it has also been suggested that the ingestible pill is more accurate than these measuring techniques.[6,7,12,16] when temperatures were compared to the only other long duration study of houghton et al.,[12] who reported a 0.3 oc rise in temperature over the 30 over protocol, this present study showed a rise of 1.1 oc in the same time period. this may be due to the different testing conditions (laboratoryvs. field-based testing) or the difference in measuring techniques (tympanic vs. ingestible pill, the latter of which is more accurate). the rise in core temperature was probably due to the active muscles requiring additional blood, thus compromising blood flow to the skin and therefore limiting heat transfer to the environment.[17] other factors that may have affected core temperature include glycogen depletion, hypohydration, and the accumulation of potassium in the interstitium of the muscle[18]. however, the fact that core temperature did not reach critical levels suggests that players are able to regulate intensity of effort to prevent excessive rises in core temperature. future studies should consider measuring sprint time changes in order to establish whether batsmen are slowing down over time; something which would impact core temperature changes. limitations this study must be seen within the context of its limitations. the primary limitation is the fact that this was a laboratory-based, simulation protocol and was therefore not able to take into account all aspects of a cricket game, such as varying environmental conditions. furthermore, the impact that the crowd has on a batsmen during a normal odi could not be replicated, although verbal encouragement was given to batsmen when necessary. 42 sajsm vol. 28 no. 2 2016 conclusion the current study is the only investigation, to date, to observe a multitude of physiological responses during extended periods of batting. results show that batting is substantially more physiologically taxing than originally thought. this highlights the importance of the need for training programmes that simulate real match situations, specifically for batsmen who are required to bat for long periods of time. the type of training done by players needs to closely mimic the demands that players are faced with in real match play. furthermore, a standardised battery of tests needs to be developed that can be used for not only testing the physical fitness characteristics of batsmen but also for improving training status. consideration could then be given to the concept of specificity and current demands placed on top-order batsmen. acknowledgments: this work is based on research supported by the national research foundation of south africa. any opinion, findings, conclusions or recommendations expressed in this material are those of the authors and therefore the nrf does not accept any liability in this regard. references 1. patel dr, stier b, luckstead, ef. major international sport profiles. pediatr clin north am 2002;49(4):769-792. [doi: 10.1016/s0031-3955(02)00018-4] [pmid: 12296532] 2. duffield r, drinkwater ej. time-motion analysis of test and one-day international cricket centuries, j sports sci 2008;26(5):457-464. [doi: 10.1080/02640410701644026] [pmid:18274943] 3. noakes td, durandt jj. physiological requirements of cricket. j sports sci 2000; 18:919-929. [doi: 10.1080/026404100446739] [pmid: 11138982] 4. christie cj, todd ai, king ga. selected physiological responses during batting in a simulated cricket work bout: a pilot study. j sci med sport, 2008; 11(6):581-584. [doi: 10.1016/j.jsams.2007.08.001] [pmid:17875403] 5. fletcher j. calories and cricket. lancet, 1955;1:1165-1166. [doi: 10.1016/s01406736(55)90662-0] 6. gore cj, bourdon pc, woodford sm, et al. involuntary dehydration during cricket. int j sports med 1993;14(7):387-395. [doi: 10.1055/s-2007-1021197] [pmid: 8244605] 7. king ga. physiological, perceptual and performance responses during cricket activity. 2002. unpublished msc thesis, department of human kinetics and ergonomics, rhodes university, grahamstown, south africa. 8. pote l, christie cj. physiological and perceptual demands of high intensity sprinting between the wickets in cricket. int j sports sci coach 2014;9(6):1375-1382. [doi: 10.1260/1747-9541.9.6.1375] 9. nicholson g, cook c, o’hara j. heart rate of first-class cricket batsmen during competitive 50-over and 20-over match play. j sports sci 2009;27(suppl 2):s100. 10. petersen cj, pyne d, dawson b et al. movement patterns in cricket vary  by both position and game format. j sports sci 2010;28(1):45-52. [doi: 10.1080/02640410903348665] [pmid: 20013461] 11. vickery w, dascombe b, duffield r, et al. battlezone: an examination of the physiological responses, movement demands and reproducibility of small sided cricket games. j sports sci 2013;31(1):77-86. [doi: 10.1080/02640414.2012.720706] [pmid: 22963389] 12. houghton l, dawson b, rubenson j, et al. movement patterns and physical strain during a novel, simulated cricket batting innings (batex). j sports sci 2011;29(8): 801-809. [doi: 10.1080/02640414.2011.560174] [pmid: 21506040] 13. hopkins wg. how to interpret changes in an athletic performance test. sportscience, 2004;8:1-7. 14. sheppard b, christie cj. musculoskeletal and perceived effects during high and low volume sprints between the wickets during batting in cricket. 2012; unpublished msc thesis, department of human kinetics and ergonomics, rhodes university, grahamstown, south africa. 15. brooks ga, mercier j. balance of carbohydrate and lipid utilization during exercise: the “crossover” concept. j appl physiol (1985)1994;76(6):2253-2261. [pmid: 7928844] 16. lim cl, byrne c, lee jkw. human thermoregulation and measurement of body temperature in exercise and clinical settings. ann acad med singapore 2008;37(4): 347-353. [pmid:18461221] 17. charkoudian n. skin blood flow in adult human thermoregulation: how it works, when it does not and why. mayo clin proc 2008;78:603-612. [doi: 10.4065/78.5.603] [pmid:12744548] 18. duffield r, coutts aj, quinn j. core temperature responses and match running performance during intermittent-sprint exercise competition in warm conditions. jstrength cond res 1999; 23(4): 1238-1244. [doi: 10.1519/ jsc.0b013e318194e0b1] [pmid:19568033] http://dx.doi.org/10.1016/s0031-3955(02)00018-4 http://dx.doi.org/10.1080/02640410701644026 http://dx.doi.org/10.1080/026404100446739 http://dx.doi.org/10.1016/j.jsams.2007.08.001 http://dx.doi.org/10.1016/s0140-6736(55)90662-0 http://dx.doi.org/10.1016/s0140-6736(55)90662-0 http://dx.doi.org/10.1055/s-2007-1021197 http://dx.doi.org/10.1260/1747-9541.9.6.1375 http://dx.doi.org/10.1080/02640410903348665 http://dx.doi.org/10.1080/02640414.2012.720706 http://dx.doi.org/10.1080/02640414.2011.560174 http://dx.doi.org/10.4065/78.5.603 http://dx.doi.org/10.1519/jsc.0b013e318194e0b1 sajsm vol. 27 no. 4 2015 97 original research gluteus medius kinesio-taping: the effect on torso-pelvic separation, ball flight distance and accuracy during the golf swing b pearce,1 msc (physiotherapy); b olivier,1 phd; s mtshali,1 msc (physiotherapy); p j becker,2 phd 1 physiotherapy department, faculty of health sciences, university of the witwatersrand, johannesburg, gauteng, south africa 2 biostatistics unit, south african medical research council, pretoria, gauteng, south africa corresponding author: b olivier (benita.olivier@wits.ac.za) background. the kinesio-taping method, which is becoming increasingly popular, may provide support and stability to joints and muscles without inhibiting range of motion. objective. the aim of the study was to determine the effect of kinesio-taping of the gluteus medius muscle on x-factor (torsopelvic separation), ball flight distance and accuracy (smash factor ratio). a specific aim was to determine whether a correlation exists between hip abduction strength and x-factor, ball distance and accuracy. methods. this study is a one group pretest-posttest quasiexperimental design which took place at a golf facility. twentynine amateur golfers with handicap of scratch ±2, who were between the ages of 18and 25-years, participated in this study. biomechanical outcomes were recorded with and without kinesio-tape applied on the gluteus medius muscle of the trail leg. biomechanical golf swing analysis with the iclub™ body motion system determined the x-factor at the top of the backswing. ball flight distance and accuracy were measured with flightscope® and dominant hip abduction strength was measured with the microfet hand-held dynamometer. results. kinesio-tape is effective in improving the relative hip abduction strength (p<0.001), although the effect size was small (cohen’s d=0.24). with regard to the biomechanical outcome measures, namely x-factor (p=0.28), ball flight distance (p=0.53) and accuracy (p=0.1), there was no significant improvement. conclusion: even though the relative hip abduction strength was improved, there was no effect on golf swing biomechanics. this can be explained due to the fact that x-factor, ball flight distance and accuracy are dependent on a combination of body movements to produce the golf swing. keywords. golf, x-factor, pelvic stability, taping s afr j sports med 2015;27(4):97-101. doi:10.17159/2078-516x/2015/ v27i4a422 the goal that the professional, amateur and social golfer strives to achieve is maximum driving performance off the tee-box and an accurate trajectory. to best accomplish this, the club head should be travelling at maximum speed at the point of impact between the club head and the ball.[1] the modern golf swing encourages limited lumbo-pelvic rotation during the back swing resulting in a relative increase in upper trunk rotation. the term used to describe this is the “x-factor”. the x-factor is determined at the top of the backswing and a greater x-factor is thought to facilitate high club head speed at impact. this is based on the movement pattern naturally occurring within muscle namely the “stretch-shorten cycle”.[2] increased torsopelvic separation creates an increase in stored energy, resulting in an increase in power build-up for a more forceful downswing.[3] this cycle utilises a muscle’s elastic and reactive properties to create a maximal force production, stimulating the joint proprioceptors to facilitate an increase in muscle recruitment.[4] the modern golf swing is a complex, coordinated movement of the whole body in order to create power to propel the golf ball a great distance while at the same time achieving an accurate trajectory.[5] the backswing functions to stretch the appropriate joints and muscles and position the body and the club head so that the golfer can perform the downswing with power and accuracy.[6] the generation of work in the golf swing comes primarily from the spine and hips, generating 69% of the total body work, with the majority of work done by the trail hip.[7] the limited lumbo-pelvic rotation required is attributed to the stabilisers within the pelvis, including the gluteal muscles and short lateral rotators of the trail hip, acting eccentrically at the top of the back swing. gluteus medius activity increases with isometric, closed chain, rotational forces, all of which form components of the golf swing.[8] this lateral stability, contributed to by the gluteus medius, limits the lumbo-pelvic rotation in the backswing allowing an increased upper torso turn.[9] this results in an increased x-factor, creating a store of potential energy in the torso to be utilised in the downswing. transfer of power from the club to the ball enhances club head and ball speed, thus distance and accuracy.[3] sports taping is a muscle facilitation technique widely used in sport and rehabilitation for the prevention of injury and the improvement of muscle function.[10] the kinesio-taping (kt) method, which is becoming increasingly popular, claims to provide support and stability to joints and muscles while at the same time aiding in pain free range of motion.[10] depending on how the kt is applied to the skin, various benefits were proposed, including alignment of fascia, stimulation according to the position of tape on the skin and the provision of specific sensory stimulation to the tissues in order to assist or limit movement.[10] smooth muscle exists within the fascia and is innervated by intrafascial nerves enabling the fascia to actively contract.[11] it can thus be postulated that the kt’s stimulation of the fascia may activate the smooth muscle within it to contract and activate the muscle it envelopes. the skin can be stretched and stimulated, activating the cutaneous mechanoreceptors which signal information about joint motion and position sense. the kt’s application on the skin may contribute to proprioception by means of the abovementioned mechanism. there is not much research on the ability of the kt to increase muscle force output, and the clinical benefits of its application remain unclear.[12] a recent systematic review reports little high-quality evidence to support the efficacy of the kt.[12] another systematic review assessing the effectiveness of the kt concluded similarly that there was no positive effect in the kt intervention group versus the placebo group when testing quadriceps muscle strength.[13] there is limited research on how gluteus medius activity affects the golf swing, but this muscle has been well-documented as an active pelvic stabiliser.[8] the primary aim of this study was to assess the effect of the kt on the gluteus medius muscle on hip mailto:benita.olivier@wits.ac.za http://dx.doi.org/10.17159/2078-516x/2015/v27i4a422 http://dx.doi.org/10.17159/2078-516x/2015/v27i4a422 98 sajsm vol. 27 no. 4 2015 abduction strength. the secondary aim was to determine whether a correlation exists between hip abduction strength and the x-factor, ball distance and accuracy. methods twenty-nine registered students from a golf facility gave informed consent to participate in this study. male golfers with a golf association handicap of scratch ±2 and between 18and 25-years old were included. golfers with a history of previous trauma or severe injury, including fractures, vertebral joint or disc injuries, or suffering from a current injury, were excluded from the study. participants were randomised according to those who would be wearing the kt and those who would not use the kt on the first test day. the converse occurred on the second test day. each participant carried out a standardised five-minute warm-up routine, consistent with their academy’s warm-up protocol, followed by five warm-up golf swings with their own driver. there are certain characteristics of a driver that affects ball flight distance and accuracy, including shaft stiffness, shaft length and club face loft.[3] this would not affect this one group pretest-posttest quasi-experimental study as each participant’s data with the kt was compared to the same participant’s data without the kt, using the same driver in both instances. this warm-up was done prior to hip abduction strength testing and the kt application. the kt application was standardised and the research assistant applied it in exactly the same way on each participant (fig. 1).[14] two “i” strips of tape were used and applied proximal to distal. the first strip was applied with the participant in the side-lying position with the dominant hip on top and in adduction. this strip was anchored, without tension, to the lateral lip of the iliac crest, lateral to the anterior superior iliac spine. the tape was activated at proximal anchor point and laid over the gluteus medius with slight tension due to the adduction of the hip. the tape was anchored distal to the greater trochanter laterally. the second “i” strip was anchored to the iliac crest lateral to the posterior superior iliac spine. the hip was placed in flexion and adduction. the distal anchor point was the skin over the lateral greater trochanter. the iclub™ body motion system (bms), created and manufactured by (iclub™ inc., florida, usa) was used to analyse the body angles and speeds of activity of each participant’s golf swing, to obtain information relating to the x-factor, shoulder and hip rotation angles and speeds. each participant, in turn, was fitted with the body motion system vest which was adjusted to fit the participant’s body. the participant stood on the pre-marked testing area in front of the golf driving range. the participant carried out ten shots off an artificial turf tee box. the same standard range ball brand was used by each participant. each participant used his own driver to represent the swing and ball flights experienced while playing. flightscope®, created by edh, ltd., south africa, is a tracking golf radar that accurately measures ball flight and club tracking. information gathered by the flightscope® includes club head speed, ball speed, smash factor ratio (accuracy) and ball distance. the swing point of interest for the x-factor calculation was calculated as the difference between the upper torso rotation angle and the pelvic rotation angle at the top of the backswing.[3] the main focus was on the point of ball fig. 1. kinesio-taping of the gluteus medius muscle the test was conducted over a period of two days. the procedure was identical for both groups. the non-tape group would have their strength test without the kt and thereafter the swing test would be conducted. on the following test day they would have their strength test with the kt applied and thereafter their swing test would be conducted, and vice versa. the isometric hip abduction strength test was carried out on the participant’s dominant gluteus medius muscle (corresponding to the trail leg in the golf address position) with a microfet handheld dynamometer (hogan industries, draper, ut) by the researcher. kolber et al.[15] concluded that handheld dynamometry is reliable for measuring muscle strength (icc 0.971-0.972). the average of three force tests was calculated. the participant was placed in the side-lying position, with the dominant hip in neutral rotation and slight extension, and was asked to abduct the hip to approximately 30°. the researcher stabilised the pelvis with one hand and applied medially directed resistance with the dynamometer in the other hand, just proximal to the greater trochanter of the femur.[16] sajsm vol. 27 no. 4 2015 99 contact, in order to measure club head speed and ball speed, and ball landing distance. the data gathered in the taped and non-taped groups were analysed using a paired student’s t-test, when testing at the 0.05 level of significance. effect sizes were calculated using cohen’s  d where effect sizes of 0.2, 0.5 and 0.8 were interpreted as small, medium and large, respectively. correlation between gluteus medius and the x-factor, ball flight distance and accuracy, with and without the kt application, was done using the pearson correlation analysis. ethical approval was granted by the human research ethics committee of the associated tertiary institution (reference number m10536). results table 1 summarises the mean values with respect to the outcome measures investigated, including hip abduction strength, the x-factor, ball flight distance and smash ratio (accuracy), with and without kt application. the strength of hip abduction was increased when kt was applied to the muscle (p<0.001), with a small effect size (cohen’s d) of 0.24. kt application did not have a significant effect on the x-factor (p=0.28), ball flight distance (p=0.53) and accuracy (p=0.1), despite the increase in hip abduction strength. furthermore, no meaningful relationship could be established between hip abduction strength and the biomechanical variables (x-factor, ball flight distance and smash ratio), with and without the kt (table 2). table 1. comparison of mean variables with and without the kt (n=29) variable mean (±sd) without kt mean (±sd) with kt mean (±sd) difference confidence interval p-value effect size (cohen’s d) hip abduction strength (n) 234 (±41) 244 (±39) -10 (±14.7) -15 to -4 <0.001* 0.24 x-factor (˚) 57 (±10) 59 (±8) -1 (±6) -4 to 1 0.28 0.14 ball flight distance (m) 269.5 (±15.1) 268.5 (±16.9) 1.0 (±8.7) -2.3 to 4.3 0.53 0.06 accuracy (smash factor ratio) 11.43 (±0.03) 1.42 (±0.03) 0.01 (±0.03) -0.002 to 0.21 0.10 0.33 kt=kinesio tape; n=newton; °=degrees; m=metres * significant differences between variables with the kt and without the kt are indicated by p<0.05 table 2. relationship between gluteus medius strength, and the variables with and without the kt (n=29) variable r-value without kt p-value without kt r-value with kt p-value with kt x-factor (°) -0.28 0.15 -0.46 0.01* ball flight distance (m) 0.09 0.66 -0.03 0.90 smash ratio -0.29 0.13 -0.33 0.08 kt=kinesio tape; °=degrees; m=metres * level of significance is set at p<0.05 discussion hip abduction strength improved with the application of the kt, although the effect size was small. a reason for this improvement could be that taping a muscle may augment the pull of the fascia on the muscle which would be effective in enhancing sufficient force on this muscle to create a positive change.[14,17] this could confirm that the kt application has an effect on the smooth muscle cells within the fascia, facilitating them to contract, without hampering range of motion. another possible mechanism for improvement of force production could be kt’s effect on the neural pathways by stimulation of afferent neural receptors. the kt’s ability to re-educate the neuromuscular system was corroborated in a study conducted on the effects of taping on scapular kinematics and muscle strength.[18] the results in this study showed that taping was successful in creating positive changes in scapular motion and muscle strength. according to the hypothesis for the present study, participants who improved most in their hip abduction strength after the kt application should also have shown a concurrent improvement in the other variables tested, namely, the x-factor, ball flight distance and accuracy. however, this was not shown in this study. this finding could be due to the individuality among the participants, each having their own unique style of coordinating the golf swing components. applying the kt to a participant’s pelvis may adversely alter the usual pelvic mechanics. this result may change if the participant practices with the tape application over a period of time, in order to get used to the muscle facilitation created by the tape. another reason for the lack of improvement in the x-factor could be that despite the improvement in strength in one muscle, may not necessarily lead to an improvement in the golf swing as a whole, as many muscles act in unison to create the golf swing.[5] stretching the hip and trunk maximises the x-factor produced. if any one of the hip and pelvic stabilising muscles are weak, such as the gluteal muscles, the hip adductors or lateral rotators or the pelvic stabilisers as a whole, the pelvis would not remain still and will rotate with the torso and shoulder girdles, thereby diminishing the x-factor.[3] other than the gluteus medius, specific pelvic stabilisers, such as the gluteus maximus with its greater volume, or the short external rotators with their large physiological cross-sectional area and short fibres, may play a greater role in pelvic stability and the x-factor, by storing potential energy and developing power for the downswing.[19] a lack of trunk rotation range of motion, altered internal or external rotation of the hips, decreased shoulder girdle movement and upper torso dissociation control, or all of the above, may also adversely affect the x-factor. the results showed no meaningful relationship between hip abduction strength, the x-factor, ball flight distance and accuracy. these are, however, not the only contributing factors to ball flight distance; swing speed, timing of the kinetic chain and accuracy of ball strike being equally important.[6,20] a change in any of these factors could adversely alter the ball’s flight. due to the complicated nature of the golf swing and the countless synchronised components, there 100 sajsm vol. 27 no. 4 2015 is a very small margin of error, and many variables (rotation angles, speed of movement, weight shift, timing of ball strike, technique) that could affect the flight of the ball.[21] the torso-pelvic separation differential, the rate at which this occurs in the backswing, and the rate of turn during the downswing, are all considered important variables in achieving further ball flight distances.[22] although muscle strength improvement was statistically significant, the effect size was low. thus this result may not be clinically significant. furthermore, hip abduction isometric strength measured in the side-lying position may not reflect the change in muscle function that may occur with weight-bearing and sports-specific tasks. according to souza and powers,[9] the gluteus medius functions eccentrically to control hip adduction and internal rotation during weight-bearing. thus a more thorough assessment of the hip during the golf swing may provide greater insight into the relationship between hip abduction strength and limited lumbo-pelvic rotation. the application of the kt on the gluteus medius had no significant effect on the accuracy of the swing, with a mean difference of only 0.01. a possible reason for this is that the golfers tested all have a  low handicap, with their swing being considerably more efficient than golfers with a higher handicap. an efficient swing will produce a ball speed (bs) as close to one and a half times the club head speed (chs) as possible (bs/chs = 1.5), indicating that the ball was struck in the “sweet spot” of the club.[23] an already efficient swing does not leave much room for improvement, as the accuracy was already excellent without any intervention. one may find a greater impact through the use of the tape in the higher handicap group, as their accuracy is less consistent and further away from the ideal ratio of 1.5.[23] results in this study may show that the participants improved in certain of the outcomes, but the improvements were in different parameters which were inconsistent in each of the participants. due to the complexity of the golf swing it could be argued that an improvement in a parameter, no matter how small, could be beneficial in improving the outcome of the golf shot.[21] the golfers participating in this study were all high-level amateurs. as this makes up only a small percentage of the general golfing population, consideration should be given to the fact that the golf swings analysed and the outcomes measured in this study may not be representative. therefore these findings should not be extrapolated to the average golfer. furthermore, only one muscle was targeted in this study and there are many muscles (and other factors) that impact on the golf swing. the significant difference in muscle strength may also have been due to a learning effect, as the conditions may have been familiarised by the participants. further research should include a long-term follow-up study investigating the effect of an extensive exercise programme, including strengthening of the pelvic stabilisers, trunk rotation mobility and scapular stabilisation on the biomechanics of the golf swing. thus not only gluteus medius strength, but also gluteus medius coordination, timing and sequencing in the golf swing should be investigated. conclusion the purpose of the study was to determine the effect that the kt has on gluteus medius strength, the x-factor in the golf swing, driving distance and accuracy of the swing. the results showed that the gluteus medius kt successfully improved the strength of hip abduction, to a limited extent. however, it did not impact significantly on the x-factor, ball flight distance and accuracy consistently among the participants. a possible reason for this is the complexity of the golf swing and how its precision is based on many elements of the kinetic chain. the improved strength of one muscle may not be sufficiently significant to change movement throughout the kinetic chain and may be reliant on the sequential firing and timing of the many muscles involved in the golf swing. the results of the study have shown that it may be beneficial to incorporate the use of the kt to facilitate muscle action. the customised application of the kt on each individual golfer may be more beneficial if it is used according to their specific strength requirements. overall, current research shows that there is insufficient evidence to support the efficacy of the kt in muscle facilitation and further research is required.[12,13,24] clinical relevance. this study provides preliminary evidence for the efficacy of the kt applied to a specific muscle. the results showed that the gluteus medius kt successfully improved the strength of hip abduction but did not impact significantly on the x-factor, ball flight distance and accuracy consistently among the participants. the improved strength of one muscle may not be significant enough to change movement throughout the kinetic chain due to the complexity of the golf swing and the many elements of the kinetic chain. it is thus essential to assess each golfer individually so as to highlight problematic areas in order to develop a specific training and intervention programme. conflicts of interest and source of funding. none declared. acknowledgements. all golfers who participated in this study, as well as danny baleson, gavin groves and ian corbett from the world of golf. references 1. burden am, grimshaw pn, wallace es. hip and shoulder rotations during the golf swing of sub-10 handicap players. j sports sci 1998;16:165-176. 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to support the growth of biomechanics in the country. the mission of sasb is to advance the field of biomechanics in south africa by supporting high quality research and promoting the translation of research into practice by (i) providing a forum for the exchange of knowledge on biomechanical theory and application, (ii) supporting the training and education of student biomechanists, and (iii) facilitating networking between practitioners, researchers, institutions and industry. the 1st conference of sasb was held as a virtual event on 28-29 october 2021. the theme of the conference was “foundations to frontiers” and the world class line-up and keynote and tutorial speakers (listed below) delivered presentations that addressed the full continuum from fundamental biomechanical methods to ground breaking research and innovation.  jacqueline alderson: “poses, loads and bridges: the asset of rigour”  felipe carpes. “why are cross-bridges important in biomechanics? the benefit of being interdisciplinary”  ezio preatoni. “skills, coordination and movement variability in sport: potential and pitfalls”  amy wu. “towards dynamic locomotion and balance at the intersection of biomechanics and robotics”  john cockcroft. “foundations for building a data processing pipeline: a practical introduction to typical tasks and available tools”  friedl de groote. “musculoskeletal modelling and simulations to analyze measured data and predict movement patterns: overview and hands-on demo in opensim” attendees were also treated to a conversational session with erica bell about lessons learned during her journey in biomechanics, and talks from the conference sponsors – “motion capture: the paradox of choice”, by felix tsui (vicon motion systems ltd) and “is markerless tracking of 3d human pose accurate”, by scott selbie (theia markerless, inc). awards were presented for the top three scientific presentations to charné britz, devon coetzee and cassidy de frança. their abstracts are published in these proceedings. the recordings of selected sessions are publicly available on the sasb vimeo channel and all keynote and tutorial sessions are available to sasb members on our website: www.biomechsa.org. organisers: helen bayne, university of pretoria; yumna albertus, university of cape town; john cockcroft, stellenbosch university; mark kramer, north west university s afr j sports med 2022; 34:1-13. doi: 10.17159/2078-516x/2022/v34i1a13377 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13377 https://orcid.org/0000-0002-2520-4937 https://orcid.org/0000-0002-6563-8596 https://orcid.org/0000-0003-4631-7591 https://orcid.org/0000-0003-2237-7549 3 the effect of eccentric and concentric cycling ergometry rehabilitation on gait, post total knee arthroplasty yumna albertus1, sandhya silal1, michael posthumus1 and nicholas tam1 1 health through physical activity, lifestyle and sport research centre (hpals), department of human biology, university of cape town. international federation of sports medicine (fims) collaborative centre of sports medicine, cape town, south africa presenting author email address: yumna.albertus@uct.ac.za introduction: total knee arthroplasty (tka) procedures are known to improve joint-specific outcomes. however, functional deficits post-surgery have been noted, particularly in terms of movement abnormalities and quadriceps weakness. eccentrically-based rehabilitation has been shown to improve muscle strength and reduce metabolic demand. thus we aimed to determine the effects of an eight-week eccentric and concentric cycling ergometry exercise intervention in tka recipients, especially on the joint kinematics and muscle activity during walking gait. methods: eighteen participants, three to nine months post total knee arthroplasty, were recruited and randomly assigned to either an eccentric (ecc) or concentric (con) cycling exercise intervention group. participants performed three exercise sessions weekly over a progressive eight-week period on the grucox isokinetic ergometer. walking gait biomechanics, knee functional outcomes and quality of life were recorded preand postintervention. results: the con group knee flexion range of movement and peak knee flexion increased significantly during the swing phase of gait (p = 0.021) post-intervention. no significant changes in kinematics and kinetics were noted in the ecc group post-intervention. the ecc intervention group showed neuromuscular changes with a decrease in biceps femoris activity during the load acceptance phase of gait (ecc pre 12.1% (11.4% 15.1%) and post 8.1% (5.9% 12.7%); p = 0.021). significant correlations between knee joint stiffness and the quadriceps:hamstring co-activation ratios were observed in the con group pre-intervention (r = -0.68; p = 0.042). conclusion: the eccentric intervention resulted in neuromuscular adaptations consistent with a move towards a more typical asymptomatic gait pattern. the concentric intervention yielded kinematic changes however, these results show eccentric training’s role in early stage postoperative rehabilitation is limited. based on the findings from this exploratory study, the benefit of eccentric training as an adjunct to rehabilitation and its role in contributing to greater improvements in the restoration of functional ability post-tka needs to be further explored. 4 characterizing the influence of a prosthesis on the shot put movement nathanael boulle1, taahirah mangera1, frank kienhöfer1 1school of mechanical, industrial and aeronautical engineering, university of witwatersrand presenting author email address: 1914053@students.wits.ac.za introduction: competitive able-bodied athletes have shown to benefit from biomechanical analysis. however, there is a paucity of research into the movement science of disabled athletes and uncertainty as to whether the biomechanical principles of able-bodied athletes can be applied to disabled athletes. this investigation seeks to provide principles for improved shot put outcomes for an athlete using a lower limb prosthesis, and determine whether able-bodied literature can be applied to disabled movement science for the shot put movement. methods: motion data was collected using an xsens mvn analyse motion capture system and ground reaction force data was collected using a fdm pressure walkway. the captured data was used to articulate and validate a rigid multibody model developed in simscape multibody, a simulation environment provided by matlab. the model was lower body specific and computed results including combined segmental velocity data, joint torques, normal and frictional forces. the simulation was validated using measured displacements from xsens as well as measured ground reaction forces from the pressure walkway compared against computed normal force data. results: the main biomechanical principles of able-bodied shot put athletes were found to be concerned primarily with segmental velocity, centre of gravity (cg) profile, feet sequencing and trunk. the principle investigation emphasized the initial glide in the preamble as well as the delivery stride. significant areas of influence for the prosthesis are characterized by a reduced delivery stride width, impaired sequential muscle activation and difficulty in providing an effective base from which the upper body segments can extend conclusions: the evidence of the investigation indicates that the utilization of able-bodied movement principles is useful in disabled sports science. moreover, the principles could even be observed as fundamental theory for any given shot putter, or by extension any projectile based sport. 5 reliability of step impact asymmetry metrics obtained using wearable sensors during netball-specific drills charné britz¹, helen bayne¹, james clark¹ 1department of physiology and sport, exercise medicine and lifestyle institute, faculty of health sciences, university of pretoria presenting author email address: charne.britz@semli.co.za introduction: inter-limb asymmetry in lower limb biomechanical load associated with step impacts has been proposed as a measure that may be useful for monitoring injury risk and rehabilitation progression. inertial measurement units (imus) are feasible monitoring tools to monitoring cumulative step impact load for each limb separately. studies show that imus can reliably assess step impacts during running-based sport movements. little is known about the reliability of inter-limb asymmetries derived from step impact metrics during netball-specific movements. the aim of this study was to determine between-day reliability of impact load asymmetry in netball-specific drills. methods: twenty-two healthy collegiate female netball players (age: 20 ± 2 years, height: 177.6 ± 7.0 cm, mass: 69.9 ± 8.3 kg) volunteered for a study approved by the institution’s ethics committee and performed six standardised netball-specific tasks on two test occasions separated by one day. impact load was obtained for both limbs using an imu (imeasureu blue trident, vicon motion systems ltd) affixed to the lower tibia. inter-limb impact load asymmetry was calculated: ((right leg – left leg) / (right leg + left leg) x 100) for each task and compared between the two testing occasions to determine between-day reliability using the coefficient of variation (cv) and intraclass correlation coefficients (icc). results: impact load for each limb had acceptable reliability on most tasks (cv range: 11.1– 19%, icc range: 0.52 0.78), except for a small-sided game (left: cv: 23%, icc: 0.44; right: cv: 21%, icc: 0.38). impact load asymmetry showed very poor reliability across all tasks (cv: 83.4 731% icc: -0.04 – 0.17). conclusion: impact load asymmetry was not reliable between sessions for netball-specific drills, although the measure for each limb had acceptable reliability. practitioners should be aware of the limitations of this asymmetry metric. 6 linking clinical outcomes of injury and running biomechanics to kinetic risk factors for injury: how novice runners respond to running in footwear with reduced cushioning devon ross coetzee1, ross tucker2, nicholas tam1 and yumna albertus1 1health through physical activity, lifestyle and sport research centre (hpals), department of human biology, university of cape town. international federation of sports medicine (fims) collaborative centre of sports medicine, cape town, south africa 2department of organizational psychology, school of management studies, university of cape town, south africa presenting author email address: devoncoe13@gmail.com introduction the high prevalence of running injury has prompted the need to understand the link between biomechanics and injury outcome. this study aimed to investigate the potential link between running biomechanics and clinical measures of injury, namely pain or discomfort and bone oedema. additionally, this study aimed to determine the intuitive kinetic and kinematic adaptations during a 12-week running intervention when running in footwear with reduced cushioning, with focus on any changes that may influence injury risk. methods fifty-four novice runners were assigned to the traditionally cushioned (tc; n = 32) or the reduced cushioning group (rc; n = 22). bone oedema of the lower leg (mri) and pain or discomfort was measured. baseline and post-intervention biomechanical testing included motion capture and force plates to assess over ground running at 3.0 m.s-1. key variables assessed included sagittal lower limb kinematics, vertical ground reaction force (vgrf) and initial loading rate (ilr). results bone oedema was associated with greater ilr, however no other relationships existed between other injury outcomes such as pain or discomfort and injury itself. only one participant (rc) transitioned from a rearfoot to a forefoot strike pattern throughout the intervention. the rc group increased knee flexion angle over time (baseline of 16.1º ± 4.5 to post-intervention of 19.7º ± 3.0; p < 0.01) and were 3.9 times more likely to reduce foot strike angle when compared to the tc group. rc participants who reduced foot strike angle presented with a significant reduction in vgrf and accumulative load. conclusion footwear with reduced cushioning may result in kinematic strategies to dampen loading rates that would normally be dissipated by the midsole of the shoe. this may have important implications for risk of injury as ilr may be associated with an increased risk of developing bone oedema of the lower leg. 7 countermovement jump performance and asymmetry after lower limb injury cassidy de frança1, helen bayne1 1department of physiology and sport, exercise medicine and lifestyle institute, faculty of health sciences, university of pretoria presenting author email address: cassidyjaye@gmail.com introduction: due to the high incidence, burden and severity of lower limb injuries, this study aimed to identify differences in performance and interlimb asymmetry during the countermovement jump (cmj) between uninjured and previously injured athletes post lower limb injury. methods: previously injured (inj: n = 12) and uninjured athletes (con: n = 16) completed self-reported injury history questionnaires and routine cmj testing (inj 3.9 ± 1.8 months post injury). vertical ground reaction force was captured using dual force plates and force-time data was used to analyse between-group differences for cmj phase-specific asymmetry and performance variables. ethical approval was obtained prior to testing. groups were compared using independent samples t-tests (student’s t, alternatively the mann-whitney u) and cohen’s d effect sizes. results: groups showed no differences and small effect sizes for jump height, modified reactive strength index, peak power, eccentric deceleration impulse, peak landing force, and force at zero velocity, as well as asymmetry in concentric impulse, eccentric deceleration impulse, and take-off peak force asymmetry. compared to controls, previously injured athletes produced greater asymmetry in peak landing force (inj: 9.8 ± 4.9%, con: 6.0 ± 4.5%, p = 0.04) (d = 0.83), which is a novel finding. injured athletes produced lower force at zero velocity (d = 0.73), peak power and greater concentric impulse (d = 0.70). despite returning to sport, significant interlimb asymmetries in the landing phase of the cmj exist up to 6 months post injury, although jump performance has been restored. this study is limited by the small sample size and used of self-reported retrospective injury data, but the preliminary analysis will be used to inform future studies. conclusion: despite normal cmj jump performance post injury, compensatory movement strategies and asymmetries may still exist up to 6 months post injury. this may be related to an increased risk of a non-contact lower limb injury in future. 8 step-to-step changes in foot-shank coordination during initial sprint acceleration byron j. donaldson1, neil e. bezodis2, helen bayne1 1department of physiology, faculty of health sciences, university of pretoria 2a-stem research centre, swansea university presenting author email: byron.donaldson@tuks.co.za introduction: initial acceleration is characterised by step-to-step changes in kinematics. the first steps see changes in the shank angle and changes in the foot position and orientation. coaches focus on ankle mechanics during acceleration, which is directly influenced by the motion of these two segments. understanding the coordination between shank and the foot during this phase can improve understanding of acceleration technique and the contribution of shank and foot to ankle motion. methods: twenty-one sprinters (15 male, 100 m pb 10.47 ± 0.42 s; 6 female, 100 m pb 11.70 ± 0.24 s) provided informed consent and the study was approved by the institutional ethical review committee. sprinters performed three ≥20 m starts from blocks and the fastest trial was analysed. sagittal plane kinematics were captured using inertial measurement units (200 hz; myomotion, noraxon, usa). individual and group mean foot-shank coordination over the first four steps was determined using vector coding techniques. step-to-step changes were assessed based on the coordination bin frequencies and coupling angle difference scores (cadiff) between adjacent steps. results: step-to-step coordination differences were largest between step 1 and 2 (cadiff = 29.7 ± 11.3%), with progressively smaller differences between steps 2-3 (cadiff = 23.6 ± 6.9%) and 3-4 (cadiff = 16.9 ± 7.2%). there was greater anti-phase coordination (ap foot (-) 19%, ap foot (+) 16%) during the first step, however became dominated by in-phase shank (-) (ips-) and foot (-) (ipf-) coordination over step 2, 3 and 4 (ips45, 44, 42%, ipf18, 16, 18% respectively). conclusion: sprinters utilise potentially distinct foot-shank coordination during the first step. there are large step-to-step coordination changes that get progressively smaller over the first four steps of a sprint. coordination is mostly in phase and foot dominant, highlighting an important role of the foot in rotation and ankle motion. 9 physiological and sprint-kinetics related to yyir1 performances in soccer players mark kramer1, martinique sparks1, and ben coetzee1 1 physical activity, sport, and recreation (phasrec) research focus area, north-west university presenting author email address: mark.kramer@nwu.ac.za introduction: although high-speed running ability and cardiorespiratory fitness (crf) are touted as associative predictors of the yo-yo intermittent recovery run (yyir1) test performance, the evidence substantiating this is inadequate. we therefore evaluated direct crf via portable spirometry during the yyir1, and the anaerobic speed reserve (asr) by modelling the sprint-kinetics of a 40-m all-out maximal sprint speed (mss) test. methods: twenty-three male soccer players were recruited for the study. after informed consent was provided, each participant completed a yyir1 and mss test. heart rate and pulmonary oxygen uptake were continuously recorded during the yyir1. sprint-kinetics were obtained and modelled from a 40-m all-out sprint test using photocells placed at 0-m, 5-m 10m, 20-m, 30-m and 40-m distances. results: the data revealed significant differences between observed and predicted v̇o2max values (p < 0.001). the bland-altman analysis showed a mean bias between observed and predicted v̇o2max of 31%, with the limits of agreement spanning 16% above and below the mean. the asr, which served as a marker of high-speed running capacity, showed statistically significant correlations with the following sprint-based parameters: max speed (r = 0.86, p < .001), absolute power-asymptote (r = 0.65, p < .001), and relative power-asymptote (r = 0.68, p < .001), but not with any yyir1 parameters (all r < 0.20, p > .469). conclusions: the intermittent nature of the yyir1 provides a unique challenge that is not captured by data derived from either physiologicalor sprint-kinetic assessments. it is unlikely that yyir1 performances are dependent on, or predicted by, high-speed running ability, at least in university-level soccer players. subsequently, we do not recommend the use of yyir1 for determining crf, and would suggest that alternative tests with greater validity, reliability, and physiological utility be used for such purposes. 10 gait adaptability and biofeedback in older adults with diabetes suzanne martin1, simon taylor1, rajna ogrin2, rezaul begg1 1 institute for health and sport, victoria university, melbourne, victoria, australia 2bolton clark research institute, melbourne, victoria, australia presenting author email address: suzanne.martin@vu.edu.au introduction: modulation of gait parameters for adjusting foot placement to changes in the environment is called gait adaptability. although older adults with diabetes mellitus report fall incidents more frequently, their gait adaptability has not been investigated well. in this phd project, the effects of diabetes, ageing and biofeedback on gait adaptability and the agreement between two presented overground and treadmill assessments in this project for future application of the developed tools were investigated. methods: participants were 16 young adults, 16 healthy older adults and 16 older adults with diabetes. they completed overground gait and gait adaptability tests with four random conditions (step shortening, step lengthening, obstacle avoiding, walking through) at a preferred speed for quantifying gait parameters and foot placement adjustments. they then completed treadmill tests with and without targeted biofeedback. foot placement adjustments were measured and compared without biofeedback during overground and treadmill walking. three-dimensional motion capture systems, force platforms, matlab and visual3d server software quantified spatiotemporal parameters and foot placement adjustments (errors). they also presented visual targeted biofeedback. analysis of variance (anova) tested the effects of groups and conditions whereas bland and altman plots assessed the agreement between the overground and treadmill tests. results: gait parameters were not significantly different between groups when walking in the baseline. however, stance time, step velocity, double support time and foot placement adjustments increased in older adults with diabetes when they responded to goal-tasks in adaptability tests. all groups could use targeted biofeedback for their foot placement adjustments during online correction of their tasks. foot placement adjustments were comparable between overground and treadmill tests. conclusions: gait adaptability was impaired in the older adults with diabetes. however, they could use targeted biofeedback in the form of visual feedback on the monitor to reduce their errors (i.e. they improved their foot placement adjustments). novel adaptability tools in this phd project can train more adaptable gait patterns in older adult with diabetes. 11 development of intelligent wearables for the estimation of motion kinematics and kinetics marion mundt1 1institute of biomechanics and orthopaedics, german sport university cologne, cologne, germany presenting author email address: marion.mundt@uwa.edu.au introduction: motion analysis that provides insight into joint kinematics and kinetics is still restricted to laboratory set-ups. to overcome this, the aim of this thesis was to develop an easyto-use and easy-to-interpret inertial-sensor-based motion analysis system leveraging artificial neural networks (anns). during a training process, anns learn to adapt their weights and biases to predict the output of unknown test samples. this thesis aimed to estimate the ground reaction force and three-dimensional angles and moments of hip, knee and ankle joint while establishing the optimum artificial neural network architectures using simulated and measured inertial sensor data. methods: a framework to simulate inertial sensors' data based on marker trajectories collected by optical systems was developed using historical datasets. the approach was validated on newly collected data of a custom imu system. simulated and measured data was used as input to fully-connected feedforward (ff) and recurrent long short-term memory (lstm) neural networks. results: there was a good agreement of the estimated kinematics and kinetics to the ground truth data for walking and fast changes of direction. enlarging the dataset with augmentation techniques improved the results. both neural networks resulted in high accuracy, with the ff network achieving greater accuracy than the lstm. conclusions: although the ff network achieved greater accuracy than the lstm neural network, lstms require less pre-processing, do not require time normalised data and are able to make real-time predictions. therefore, lstms should still be considered in scenarios where these characteristics are favourable. the promising results of this thesis lay the foundations for biomechanical analysis outside of the lab, thus prompting further research in this direction. 12 establishing structural criteria for heavy-load carriage systems dario schoulund1 1faculty of engineering, built environment and information technology, university of pretoria presenting author email address: dario.schoulund@up.ac.za introduction: ancient and modern types of load carriage systems (lcs) coexist today worldwide. while there is a general agreement regarding which lcs are superior to others in terms of energy expenditure, the question why remains unclear. we set to answer from a structural perspective, hypothesizing that if a relationship between performance and lcs structural configuration could be established, a theoretically ideal arrangement may be defined. methods: five reportedly efficient methods of load carriage, namely tumpline, backpack, springy poles, head load and double pack were analysed as determinate structures (σfx, σfy and σm = 0), with a constant load of 150 n. excursion patterns for the load were considered at a walking speed of 1.3 m.s-1. the focus is on the relationship among load transfer areas, load paths, centre of masses, moments and the resultant range of forces exerted onto the user. the results were then compared against the extra load index (eli) values reported in literature. results: body centre of mass and load centre of mass horizontal eccentricity proved to be the main detrimental factor influencing gait adaptations and the development of shear forces for both static and dynamic conditions. load paths’ geometry, axial loads, and the magnitude of shear forces combined determined the path’s efficiency. load transfer areas and the quality of the supports requiring pre-stressing, should also be consider an external additional force acting onto the user. finally, pressure distribution showed no correlation to structural arrangement. conclusions: there exists a partial correlation between superior structures and metabolically efficient lcs. the structural analysis led to the definition of a theoretically ideal structural arrangement, which could be a promising path for further research and design. while base structural arrangements represent a critical foundation for an lcs, other less studied aspects of performance -mostly qualitative-, play a more important role than assumed for the overall performance and choice of a given lcs. 13 acute kinetic and kinematic differences between minimalist sandal, shod and barefoot running in habitually shod male recreational trail runners matthew swart1, simon de waal1, ranel venter1 1department of sport science, stellenbosch university. presenting author email address: matthew@iso.co.za introduction: a plethora of studies on minimalist running shoes exists; however, none have explored the acute biomechanical effects of running in a minimalist sandal within a habitually shod population. this study aimed to investigate the acute effects of minimalist running sandals on vertical loading rates and selected lower-limb kinematics during submaximal-level treadmill running. methods: thirteen male recreational trail runners ran on a level (0º) instrumented treadmill, at three different submaximal velocities (2.22 m.s-1, 2.78 m.s-1and 3.61 m.s-1), using three different footwear conditions: barefoot, minimalist sandal (xero shoes, colorado, us) and their conventional trail-running shoes. supplementary to the treadmill, an inertial measurement unit system was used to capture lower-limb 3d kinematic and ground reaction force data synchronously, to measure vertical average loading rate (valr), vertical instantaneous loading rate (vilr), foot strike angle (fsa), ankle dorsiflexion (ada) and knee flexion angles at contact, as well as knee flexion range of motion (rom) during the stance phase. results: pairwise comparisons revealed no significant differences between minimalist sandal and barefoot running. differences were found in fsa (p < 0.05) and ada (p < 0.05) at contact between minimalist and barefoot versus shod running. moreover, increased valr and vilr were experienced in a minimalist and barefoot condition as opposed to running in a shod condition, although the differences were not significant. conclusion: running in a minimalist sandal is similar to barefoot running. runners seeking to change from a habitually shod condition to running in a minimalist sandal or barefoot condition, should progress with caution due to the higher acute loading rates. introduction the exercise-induced stress response is an adaptational homeostatic shift intended to facilitate the demands put on the body by physical exertion. most stressors, including heat, pain, trauma and exercise, stimulate prostaglandin synthesis. the mechanisms underlying this stimulation usually involve the release of pro-inflammatory cytokines with subsequent induction of prostaglandin synthesis which influences the central neuroendocrine regulatory mechanisms. 14 this stressor-induced prostaglandin synthesis, in turn, initiates and modulates many aspects of the stress response such as neuroendocrine, autonomic nervous system, metabolic and temperature changes. the pathways through which prostaglandins are involved in the cortisol stress response include a direct influence on the release of corticotropin-releasing hormone (crh) and/or antidiuretic hormone (adh) from the paraventricular nucleus (pvn), and indirect stimulation of the pvn via the central noradrenergic neurons. 8,14 prostaglandins are further involved in the exercise-induced autonomic nervous system response 7 and in the increase in body temperature and other metabolic adaptations. 14 several other aspects of the exercise-related neuroendocrine response, which are under control of the hypothalamus and the hypothalamo-pituitary axis, are also influenced by prostaglandins and other eicosanoids. 8 it therefore speaks for itself that any medication that interferes with eicosanoid metabolism could have the potential to influence the exercise-induced stress response. eicosanoids are produced throughout the body under the influence of the cyclooxygenase (cox) activities of prostaglandin endoperoxide h synthases (pghss). two pghs isozymes exist, pghs-1 and pghs-2, commonly referred to as cyclooxygenase-1 or cox-1 and cyclooxygenase-2 or cox-2. cox-1 is thought to be constitutively expressed in virtually all tissues and to be original research article cyclooxygenase inhibitors and the exercise-induced stress response n claassen (phd)1 j snyman (mb chb, mpharmmed, md)2 a koorts (msc)1 h nolte (ma (hms) biokinetics)3 b wagenaar (msc)1 m kruger (dip nursing)1 p j becker (phd)4 m viljoen (phd, phd)1 1 department of physiology, university of pretoria 2 department of pharmacology, university of pretoria 3 sport research institute, university of pretoria 4 biostatistics unit, medical research council, pretoria abstract objective. this study investigated the effects of single dosages of the non-steroidal anti-inflammatory drug (nsaid) naproxen, and of the coxib, rofecoxib, on the exercise-induced stress response. design. eight subjects (age 20.9 ± 1.1 years, weight 70.4 ± 3.9 kg, height 170.9 ± 6.7 cm, body surface area 1.82 ± 0.09 m 2 , body mass index 24.1 ± 1.3 kg.m -2 ) took part in a double-blind, drug-placebo, cross-over design study. the experimental procedures were performed on 3 occasions on each volunteer, i.e. once on placebo, once on naproxen (single dose of 1 000 mg) and once on rofecoxib (single dose of 50 mg). results. mean post-exercise cortisol values were significantly higher than pre-exercise values with the subjects on placebo (p = 0.0365) and rofecoxib (p = 0.0208), but not on naproxen (p = 0.0732). post-exercise oral temperatures were significantly higher than pre-exercise temperature values on placebo (p = 0.0153) and rofecoxib (p = 0.0424), but not on naproxen (p = 0.5444). conclusion. the results of this study suggest a role for cyclooxygenase-1 (cox-1) in the exercise-induced cortisol and temperature response to exercise. correspondence: m viljoen department of physiology university of pretoria p.o. box 2034 pretoria 0001 tel: 012-319 2140 fax: 012-321 1679 e-mail: mviljoen@medic.up.ac.za � sajsm vol 18 no. 1 2006 cyclooxygenase inhibitors.indd 4 3/13/06 2:58:17 pm involved in normal physiological functions such as protecting the kidney and the gastric mucosa and maintaining vascular homeostasis. 14,18 cox-2, although initially thought not to exist constitutively, is now, in humans, known to be found as such in several types of tissues. 10 the expression of cox-2 can further be induced in all tissues tested thus far, and its expression is stimulated in a rapid, exaggerated fashion by mitogens, growth factors and pro-inflammatory cytokines. 10,18 it is at present assumed that cox-2, which is situated in the cerebral blood vessels and thus easily accessed by bloodborne cytokines for the induction of prostaglandins, could be responsible for many of the physical stress-induced adaptations. 14 cox inhibitors have an influence on eicosanoid metabolism and many of the effects of non-steroidal anti-inflammatory drugs (nsaids) are exerted through interference with this effect. 20 cox inhibitors block the biosynthesis of prostanoids by inhibiting the cox activities of pghss. their most generally known pharmacological effects are their anti-inflammatory, analgesic, antipyretic and platelet-inhibiting actions, but they are also said to be of value in the prevention of colon cancer (cox-2), as well as in slowing down the progression of alzheimer’s disease, 18 and there are indications that they may be of benefit during exercise by decreasing postexercise muscle soreness and decline in strength. 1 although these drugs are known for their anti-inflammatory and analgesic effects there are health risks, such as an increase in gastrointestinal permeability, associated with the indiscriminate use of anti-inflammatory drugs. 12 a number of other negative side-effects have been reported for nsaids, including potential ulcerogenic and nephrotoxic effects and there are indications that they may inhibit protein synthesis in skeletal muscle after eccentric resistant exercise, 21 augment the exercise-induced increase in gastrointestinal permeability 12 and decrease muscle blood flow during exercise. 5 the considered-safer cox-2 selective inhibitors such as rofecoxib and celecoxib have been associated with ulcer-related side-effects and increases in cardiovascular morbidity. 13 nsaids may theoretically also influence the adaptive exercise-induced stress response through suppression of the synthesis of those prostaglandins that stimulate the fever response, the sympathetic nervous system and the hypothalamo-pituitary-adrenocortical axis. 7,8,18 the frequent use of cox inhibitors by athletes is a wellknown occurrence. in view of their role in the development of the exercise-induced stress response, cox inhibitors could theoretically also be expected to have an effect on the performance of athletes. despite evidence that aspirin (acetylsalicylic acid) can modulate the secretion of many hormones, there is as yet not conclusive evidence that any of the cox inhibitors has a marked effect on the neuroendocrine and metabolic homeostatic shift of exercise, 8,16 and more research is needed. three broad classes of cox inhibitors are generally known. 9 the best known is aspirin, synthesised from salicylic acid, which inhibits the activity of cox-1 by irreversibly acetylating a serine residue at position 529. the second class is the nsaids such as indomethacin and naproxen that inhibit both forms of the enzyme, i.e. cox-1 and cox-2. the third class is the selective cox-2 inhibitors, i.e. the coxibs such as rofecoxib. this study investigated the effects of the non-selective cox inhibitor naproxen (naprosyn) and the selective cox-2 inhibitor rofecoxib (vioxx) on the treadmillinduced stress response and on the recovery period. naproxen reduces the synthesis of prostaglandins by inhibiting cox activities of both isoforms of pghss, i.e. cox-1 and cox-2. the plasma half-life of naproxen is 12 15 hours and peak plasma concentrations are seen in about 2 hours. 7,20 rofecoxib is 50 times more selective in inhibiting the cox-2 isoenzyme. the plasma half-life is 10 17 hours and peak plasma concentrations are seen in 2 3 hours. 9 although referred to as a cox-2 inhibitor, an alternative term to cox-2 inhibitor would be ‘cox-1 sparing’. the aim of this study was to investigate the effects of single dosages of the nsaid, naproxen (1 000 mg), and the coxib, rofecoxib (50 mg), on the expression of the treadmillinduced stress response as reflected in free salivary cortisol levels, heart rate, oral temperature and other metabolic parameters. methods subjects and experimental design the effects of the 2 nsaids on the exercise-induced stress response were investigated in healthy students in a doubleblind, drug-placebo, cross-over design study in which each subject served as his/her own control. all tests started at the same time of the day and experimental conditions were similar for all exposures. the mean age of the students (n = 8) was 20.9 ± 1.1 years, weight 70.4 ± 3.9 kg, height 170.9 ± 6.7 cm, body surface area 1.82 ± 0.09 m 2 and body mass index 24.1 ± 1.3 kg.m -2 . during the first week of the study students had general medical examinations and those with either hypertension (> 140/90 mmhg), hypotension (< 100/60 mmhg), or any other pathological condition or risk factor, as well as students on chronic medication or performance-enhancing drugs were excluded. students who developed any health complication such as colds or flu during the study were excluded. other than the treadmill procedures of the study no strenuous physical activity was allowed over the 4 weeks each subject was involved in the study and subjects had to refrain from alcohol intake on the days before the experiments. during the same week the maximal oxygen consumption (vo2max) of each student was determined, the procedures of the study explained and informed consent forms signed. ethical clearance (research ethics committee, faculty of health sciences, university of pretoria, clearance number: sajsm vol 18 no. 1 2006 � cyclooxygenase inhibitors.indd 5 3/13/06 2:58:17 pm 173/2002) was obtained for the study and all participants gave written informed consent. testing and procedures the experimental procedure was performed on 3 separate occasions by each participant, i.e. once on placebo, once on naproxen (single dose of 1 000 mg) and once on rofecoxib (single dose of 50 mg) swallowed 2 hours before initiation of the treadmill procedure. the drug or placebo was administered randomly by a third party in a cross-over design study performed double blind. a washout period of 7 days passed between the experimental days. testing started at the same time of day in consideration of circadian rhythmicity. the vo2max tests comprised incremental increases in running speed at a constant gradient of 2°. the following protocol was used: 3 minutes at 8 km.h -1 and 2 minutes at 10, 12, 14, 16 and 17 km.h -1 respectively on a motorised treadmill with the subjects clothed in jogging shoes and light clothing. expiratory oxygen, carbon dioxide and heart rates were continuously measured every 10 seconds during the tests (schiller cardiovit, cs100, baar, switzerland). the study proper started the second week. on arrival for the experiment (07h00) the heart rate monitor was fitted, oral temperature was taken sublingually for 3 minutes using a clinical thermometer and thereafter a salivary sample was collected for cortisol determination. this is referred to as time pre1. thereafter the drug or placebo was administered and a standardised breakfast consisting of toast and fruit juice was consumed. two hours after administration of the drug/placebo the oral temperature was again taken and saliva collected for cortisol analysis (pre2). the treadmill procedure consisting of 3 exercise intensities equivalent to 50%, 60% and 75% of maximal oxygen expenditure for 10, 15, and 5 minutes, respectively, was started immediately. heart rate recordings were obtained continuously throughout the procedure. salivary samples were again collected at the end of the exercise protocol (post1), and at 30 minutes (post2), 60 minutes (post3) and 120 minutes (post4) post-exercise. the collected salivary samples were centrifuged at 1 000 g for 10 minutes at 4ºc and aliquots of the supernatants were transferred to eppendorf tubes and stored at –20ºc until analysis by enzyme-linked immunosorbent assay (elisa) (drg gmbh, marburg, germany). oral temperatures were recorded at the same times salivary samples were taken. statistics data were analysed using the appropriate analysis of variance (anova) for a three-period cross-over experimental design, with factors for treatment period, treatment, carry-over and subjects. the analyses were also done by adjusting for baseline values, i.e. baseline values were used as covariates. the covariates were not significant for any of the variables. within treatments, the exercise-induced effect was assessed using the paired t-test after establishing that there was no carry-over effect between treatments. as the sample was relatively small the conclusions for the latter were confirmed using wilcoxin’s matched pairs signed-rank test. differences were considered statistically significant when p < 0.05. 19 results table i (a-c) shows the means, standard deviations and pvalues (one-way anova) for cortisol, heart rate and oral temperature directly before the drug/placebo was administered (pre1), 2 hours after drug/placebo administration, i.e. directly before initiation of the treadmill procedure (pre2), immediately after completion of the treadmill procedure (post1), 30 minutes after the treadmill procedure (post2), 60 minutes after the treadmill procedure (post3), and 2 hours after the treadmill procedure (post4). no significant differences were seen between the values obtained on placebo and with either of the 2 nsaids, or between the values on naproxen and on rofecoxib. table i (d) shows the peak values obtained during exercise for the metabolic parameters. no significant differences were found between the values obtained on the drugs and placebo or between those on the 2 drugs. the exercise-induced response and the post-exercise recovery for the various parameters are recorded in table i. it can be seen that the treadmill procedure served its function as physical stressor as typical stress responses were observed over the exercise period in all 3 groups. the mean post-exercise cortisol values (post1) were significantly higher than the pre-exercise (pre2) cortisol values with the subjects on placebo (p = 0.0365) and rofecoxib (p = 0.0208), but not on naproxen (p = 0.0732). there were, however, no significant differences between the exercise-induced increases in cortisol secretion (post1 minus pre2) with subjects on placebo, naproxen and rofecoxib (p = 0.9055). the mean post-exercise heart rate (post1) was significantly higher than the pre-exercise (pre2) heart rate values with subjects on placebo (p = 0.0001), naproxen (p = 0.0001) and rofecoxib (p = 0.0001). no significant differences were found between the exercise-induced increases in heart rate in the 3 groups (p = 0.3841). the post-exercise temperature (post1) was significantly higher than the pre-exercise (pre2) temperature values on placebo (p = 0.0153) and rofecoxib (p = 0.0424), but not on naproxen (p = 0.5444). once again no statistically significant differences were found between the exercise-induced responses on the 3 substances (p = 0.6701). the mean post-exercise mets (1 met = 3.5 ml o2.kg -1 . min -1 ; post1) was significantly higher than the pre-exercise (pre2) mets values on placebo (p = 0.0001), naproxen (p = 0.0001) and rofecoxib (p = 0.0001). the means of the oxygen expenditure at 75% vo2max (vo2/min and vo2/kg/min) were significantly higher than the pre-exercise expenditure on placebo (p = 0.0001 and p = 0.0001), naproxen (p = 0.0001 and p = 0.0001) and rofecoxib (p = 0.0001 and p = 0.0001). no statistical differences were, however, found in the increases (∆) over the exercise period for mets, vo2ml/ min or vo2ml/min/kg between subjects on placebo, naproxen or 6 sajsm vol 18 no. 1 2006 cyclooxygenase inhibitors.indd 6 3/13/06 2:58:18 pm rofecoxib (p = 0.5122; p = 0.4764; p = 0.4433). no statistically valid differences were found over the recovery period between the results obtained on the 2 drugs or between the drugs and the placebo. discussion in this study good stress responses were observed over the treadmill procedure for all parameters tested, indicating that the exercise regimen was correct. there were no significant differences between the absolute values over time for any of the stress parameters irrespective of whether the subjects were on placebo, naproxen or rofecoxib. significant increases were found for all stress parameters over the exercise period (post1 v. pre2) when subjects were on placebo and on rofecoxib, respectively. however, the pre-post increases in cortisol concentrations and oral temperatures were not statistically significant with subjects on naproxen. naproxen, as previously mentioned, belongs to the second class of antiinflammatory drugs that inhibit both forms of the enzyme, i.e. cox-1 and cox-2. rofecoxib, on the other hand, belongs to the third class, i.e. the selective cox-2 inhibitors. the fact that the non-selective cox inhibitor, naproxen, but not the selective cox-2 inhibitor, rofecoxib, had an inhibiting effect on the cortisol and temperature response is an indication that the suppressive effects may be mediated by suppressing cox-1 activity. the results of this study are unexpected as one would have thought that rofecoxib rather than naproxen would have had the suppressive effect. in theory, the slightly longer time to peak plasma concentration (cmax) for rofecoxib than for naproxen might have been a confounding factor, which would have meant that the exercise could have been performed before peak plasma values were reached. this should, however, have been reflected in the recovery period. this table i. between-treatment comparisons for mean cortisol, heart rate, oral temperature and mets over the experimental period. exercise-induced values represent the change in the respective values of the variables from either pre2 to post1 (cortisol and oral temperature) or pre2 to 7�% of vo2max during exercise (heart rate and mets). (pre1 = t0 min, pre2 = t120 min, post1 = t1�0 min, post2 = t180 min, post3 = t210 min, and post� = t270 min.) variable placebo (± sd) naproxen (± sd) rofecoxib (± sd) pre 1 7.6 ± 3.7 7.8 ± 6.4 7.4 ± 3.6 a. pre 2 1.8 ± 1.5 1.4 ± 1.3 1.1 ± 0.6 mean cortisol concentration (ng/ml) post 1 3.8 ± 2.8 3.0 ± 1.7 3.8 ± 2.4 post 2 2.7 ± 1.7 3.2 ± 1.3 3.6 ± 2.4 post 3 1.4 ± 1.0 2.0 ± 0.7 2.1 ± 1.2 post 4 0.8 ± 0.5 1.7 ± 1.2 1.6 ± 1.3 pre 87.8 ± 8.6 83.6 ± 5.6 83.7 ± 10.1 b. 50% 113.8 ± 8.9 112.6 ± 12.1 111.1 ± 7.5 mean heart rate (beats/min) 60% 148.1 ± 21.2 148.2 ± 19.6 156.2 ± 15.5 75% 162.8 ± 13.3 169.8 ± 13.1 159.8 ± 24.2 post 120.2 ± 18.0 122.9 ± 25.2 114.5 ± 11.8 pre 1 36.5 ± 0.2 36.4 ± 0.3 36.2 ± 0.3 c. pre 2 36.5 ± 0.2 36.5 ± 0.4 36.2 ± 0.3 mean oral temperature (ºc) post 1 36.7 ± 0.3 36.6 ± 0.3 36.6 ± 0.3 post 2 36.9 ± 0.1 36.6 ± 0.4 36.8 ± 0.2 post 3 36.7 ± 0.3 36.6 ± 0.2 36.7 ± 0.2 post 4 36.6 ± 0.3 36.6 ± 0.2 36.5 ± 0.3 rest 1.1 ± 0.6 1.1 ± 0.5 0.9 ± 0.8 d. 50% 4.6 ± 0.9 5.1 ± 0.9 5.1 ± 1.0 mets 60% 6.9 ± 1.2 7.4 ± 1.5 7.6 ± 1.4 75% 7.8 ± 0.8 8.6 ± 0.9 8.0 ± 1.6 ∆ met 6.6 ± 0.7 7.5 ± 1.0 7.1 ± 1.3 ∆ vo2/min 1.6 ± 0.2 1.9 ± 0.3 1.7 ± 0.3 exercise-induced response ∆ vo2/kg/min 23.2 ± 2.5 26.4 ± 3.4 24.8 ± 4.4 ∆ cortisol 1.9 ± 2.1 1.6 ± 2.1 2.7 ± 2.5 ∆ heart rate 75.0 ± 15.0 86.2 ± 14.9 72.2 ± 28.4 ∆ oral temp 0.2 ± 0.2 0.1 ± 0.4 0.4 ± 0.4 sd = standard deviation; mets = 3.5 ml o2.kg -1.min-1 sajsm vol 18 no. 1 2006 7 cyclooxygenase inhibitors.indd 7 3/13/06 2:58:18 pm was not the case as there were no statistical differences for any parameter between placebo, naproxen and rofecoxib over the post-exercise recovery period. it is of interest that the lower cortisol response seen in this study with subjects on naproxen, compared with subjects on placebo, was also reported previously with aspirin. 8 further support for our findings, i.e. that cox-1 is involved in the exercise-induced stress response, is derived from indications that the cox-1 gene might be important in temperature regulation and the pyresis that occurs in the absence of infections, as opposed to cox-2 gene involvement in infectionand lipopolysaccharide-induced pyresis. 4 subsequent to completion of this study rofecoxib was voluntarily withdrawn worldwide on 30 september 2004 by merck and co. this followed the confirmation of previous results that the selective cox-2 inhibitor rofecoxib increases the relative risk for cardiovascular events such as heart attack and stroke. 3,6 stress induces upregulation of cox-2 in endothelial cells and since cox-2 selective inhibitors such as rofecoxib have no antiplatelet activities (cox-1) the imbalance between prothrombotic eicosanoids (txa2) and vasodilatory and antiaggregatory pgi2 forms the theoretical basis for the reported adverse clinical outcome. 2,17 other cox-2 inhibitors such as celecoxib are still marketed for acute and chronic inflammatory pain. the association between celecoxib and adverse cardiovascular outcomes seems to be less pronounced. 11 the reason for this is not clear but may be due to different pharmacokinetics compared with rofecoxib. valdecoxib has also been associated with an increase in reinfarction rates in patients receiving the drug after a myocardial infarction. 15 the potential for adverse cardiovascular events therefore seems to be related to the mechanism of action of cox-2 inhibitors. the frequent use of nsaids by athletes before, during and after competitions raises the question whether it may have an influence on the exercise-induced stress response. this, and other investigations indicate that anti-inflammatory drugs may have an effect on the exercise-induced stress response and that the performance and perhaps even health of the athletes may be negatively affected by the use of these drugs. the results of this study therefore indicate that more care needs to be taken with the selection of nsaids if athletes have to use them during training and competitions. coaches and physical conditioning specialists also need to be informed about the different physiological mechanisms that are influenced by nsaid drugs. this will enable them to give athletes proper advice with regard to the use of nsaids. it may further also help coaches and physical conditioning specialists to understand the development of certain unexpected exercise-induced stress responses if the athlete uses a specific nsaid. conclusion although the results of this study point towards a role for cox-1 in the exercise-induced cortisol and temperature response, more studies of this nature, as well as studies involving nsaids and endurance exercise, are urgently required to come to a better understanding of the exact role of coxs in the exercise-induced response and therefore of the potential effects of nsaids. the authors would like to thank the subjects who participated in this study. the opinions, interpretations, conclusions and recommendations are those of the authors and do not constitute endorsement of the products used in this investigation. the data collection and technical efforts of dr m blom and dr m van wyk are also gratefully acknowledged. references 1. baldwin ac, stevenson sw, dudley ga. nonsteroidal anti-inflammatory therapy after eccentric exercise in healthy older individuals. j gerontol a biol sci med sci 2001; �6: m510-3. 2. belton o, byrne d, kearney d, leahy a, fitzgerald dj. cyclooxygenase-1 and -2-dependent prostacyclin formation in patients with atherosclerosis. circulation 2000; 102: 840-5. 3. bombardier c, laine l, reicin a, et al. comparison of upper gastrointestinal toxicity of rofecoxib and naproxen in patients with rheumatoid arthritis. n engl j med 2000, 3�3: 1520-8. 4. botting r. cox-1 and cox-3 inhibitors. thromb res 2003; 110: 269-72. 5. boushel r, langberg h, gemmer c. combined inhibition of nitric oxide and prostaglandins reduces human skeletal muscle blood flow during exercise. j physiol (lond) 2002; ��3: 691-8. 6. bresalier rs, sandler rs, quan h, et al. cardiovascular events associated with rofecoxib in a colorectal adenoma chemoprevention trial. n engl j med 2005; 3�2: 1092-102. 7. de meersman re, zion as, lieberman js, downey ja. acetylsalicylic acid and autonomic modulation. clin auton res 2000; 10: 197-201. 8. di luigi l, guidetti l, romanelli f, baldari c, conte d. acetylsalicylic acid inhibits the pituitary response to exercise-related stress in humans. med sci sports exerc 2001; 33: 2029-35. 9. fitzgerald ga, patrono c. the coxibs, selective inhibitors of cyclooxygenase-2. n engl j med 2001; 3��: 433-42. 10. gilroy dw, colville-nash pr. new insights into the role of cox 2 in inflammation. j mol med 2000; 78: 121-9. 11. graham dj, campen d, hui r, et al. risk of acute myocardial infarction and sudden cardiac death in patients treated with cyclo-oxygenase 2 selective and non-selective non-steroidal anti-inflammatory drugs: nested case control study. lancet 2005; 36�: 475-81 12. lambert gp, broussard lj, mason bl, mauermann wj, gisolfi cv. gastrointestinal permeability during exercise: effects of aspirin and energycontaining beverages. j appl physiol 2001; 90: 2075-80. 13. malhotra s, shafiq n, pandhi p. cox-2 inhibitors: a class act or just vigorously promoted. medscape general medicine 2004; 6: 1-9. 14. moshonov s, zor u, naor z. prostaglandins. in: fink g, ed. encyclopaedia of stress. vol. 2. san diego: academic press, 2000: 266-372. 15. nussmeier na, whelton aa, brown mt, et al. complications of the cox-2 inhibitors parecoxib and valdecoxib after cardiac surgery. n engl j med 2005; 3�2: 1081-91. 16. przybylowski j, obodynski k, lewicki c, et al. the influence of aspirin on exercise-induced changes in adrenocorticotrophic hormone (acth), cortisol and aldosterone (ald) concentrations. eur j appl physiol 2003; 89: 177-83. 17. ray wa, stein mc, daugherty jr, et al. cox-2 selective non-steroidal anti-inflammatory drugs and risk of serious coronary disease. lancet 2002; 360: 1071-3. 18. smith wl, de witt dl. cyclooxygenase inhibitors. in: austen fk, burakoff sj, rosen fs, strom tb, eds. therapeutic immunology. massachusettes: blackwell science, 2001: 117-31. 19. stata for windows (8.0). stata corporation, texas, usa. 20. dollery c, ed. naproxen (sodium). in: therapeutic drugs. 2nd ed. vol. 2. edinburgh: churchill livingstone, 1999: n31-n36. 21. trappe ta, white f, lambert cp, cesar d, hellerstein m, evans wj. effect of ibuprofen and acetaminophen on postexercise muscle protein synthesis. am j physiol endocrinol metab 2002; 282: e551-6. 8 sajsm vol 18 no. 1 2006 cyclooxygenase inhibitors.indd 8 3/13/06 2:58:18 pm original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license position-specific physical and technical demands during the 2019 copa américa football tournament a kubayi, dphil (sport science) department of sport, rehabilitation and dental sciences, faculty of science, tshwane university of technology, pretoria, south africa corresponding author: a kubayi (kubayina@tut.ac.za) the optimal physical preparation of professional football players has become an integral part of the game, particularly due to the increased physical demands during a match.[1] technological advances have led to sophisticated systems capable of recording and processing the physical and technical data of all players during a game now being used in elite club settings. in addition, monitoring work rate profiles of players during tournaments is now possible through the use of high-quality cameras and modern computer software.[1] these computerised, semi-automated image recognition systems provide real-time movement information of all players during match play. this means more advanced analytical evaluations of the specific elements of an individual player’s match performance can be generated on a large sample of players.[2] regardless of the different methods used to assess footballers’ activity profiles,[3] players generally cover a total distance of 8– 12 km during a match, with the vast majority at low intensity, such as walking and jogging.[4] players’ physical demands based on match-related playing position have been well described in the literature.[2-5] for example, bradley et al.[3] found that wide and central midfielders covered a greater total distance than fullbacks, attackers, and central defenders in european competitions. previous research has also shown that attackers cover greater high-intensity running distances compared to players in other positions.[4] while it has been reported that total distance is not a discriminatory indicator for successful performance,[5] high-intensity activities are important for match outcomes as they contribute to team success.[2] high-intensity efforts allow players to quickly reach optimum speeds and are a crucial component of matchdeciding moments in football.[3] while previous research using semi-automatic video analysis provided useful information about physical indicators of football players, little attention has been given to information on the technical demands of players.[5] research has shown technical and tactical abilities are considered important for success in soccer.[6] in their study, dellal et al.[5] reported full backs and central defenders won most passes and heading duels in the english premier league and spanish la liga. it was further reported that wide defenders, central midfielders, and wide midfielders recorded the lowest percentage of accurate passes. in a related study, ermidis et al.[7] examined the technical demands of professional football players in the 2015 asian cup. findings showed that central midfielders performed more passes than central defenders, external midfielders, and forwards. in addition, forwards had more aerial duels than fullbacks, central midfielders, and external midfielders. in the past decade, several studies have investigated the physical and technical performance attributes of football players in asian and european domestic leagues and continental competitions.[2-5] in contrast, there is limited research on the match-play performance indicators of south american football players. such research is important because the playing styles of south american national football teams are usually characterised by skill and flair, whereas the european games are characterised by a direct style of play and ball possession.[8] therefore, given the disparity in playing styles across these two continents, a better understanding of players’ physical and technical attributes in south america would be helpful for football coaches and scientists to devise matchwinning tactics. in addition, sports scientists, coaches and fitness trainers will be able to design research, game strategy and fitness training programmes based on individual player characteristics.[9] the purpose of this study was to examine the physical and technical characteristics of football players background: despite a substantial body of literature on the physical and technical performance characteristics of football players in asian and european tournaments, research on south american football players is scarce. objectives: the purpose of the study was to examine the physical and technical characteristics of football players according to specific playing positions at the 2019 copa américa tournament. methods: a total of 180 match observations from 13 games were monitored using the instat tracking system. players were grouped into the following five playing positions: central defenders (n = 45), wide defenders (n = 46), central midfielders (n = 50), wide midfielders (n = 17), and forwards (n = 22). results: descriptive statistics (means ± standard deviations) and the one-way analysis of variance were used to analyse the data. findings showed that the total distance covered by central midfielders (10 553 ± 763 m) was significantly (p < 0.05) higher than that of central defenders (9226 ± 720 m; effect size (d) = 1.79), wide defenders (9929 ± 633 m; d = 0.89) and forwards (9383 ± 820 m; d = 1.45). wide midfielders (214 ± 170 m), wide defenders (152 ± 199 m) and forwards (138 ± 94 m) covered greater distances sprinting than central defenders (67 ± 42 m; d = 1.19) and central midfielders (91 ± 66 m; d = 0.95). concerning technical variables, central midfielders played significantly more passes compared to players in other playing positions (p < 0.05). in relation to crossing, wide defenders completed significantly more crosses than players in other positions (p < 0.05). conclusion: these findings have direct implications for tailoring tactics so players can meet the physical and technical demands of the game. keywords: distance, sprinting, match, tactics, passes s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a11955 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a11955 https://orcid.org/0000-0002-8370-3056 original research sajsm vol. 33 no. 1 2021 2 according to specific playing positions at the 2019 copa américa tournament. methods participants the sample consisted of 180 match observations from 13 games during the 2019 confederación sudamericana de fútbol (conmebol) copa américa football competition. players in this study were categorised into the following five position groups: central defenders (n = 45), wide defenders (n = 46), central midfielders (n = 50), wide midfielders (n = 17), and forwards (n = 22).[10,11] only players who finished the full 90 minutes were included in the analysis. goalkeepers, players who were replaced, and those who were substitutes were excluded from the analysis. this study received ethical clearance from the faculty of science ethics committee of tshwane university of technology. physical and technical indicators the players’ match performances were captured using the instat tracking system. their physical movement activities included walking, jogging, running, high-speed running, sprinting and completing the total distance. the instat system has been shown to be highly accurate with levels of absolute and relative reliability, typical errors (from 0.019 to 0.036) and total errors (from 0.020 to 0.037).[12] technical indicators consisted of total passes; percentage of accurate passes; shots; crosses; dribbles; total air challenges; air challenges won; tackles; percentage of tackles won; lost balls; and fouls committed. the operational definitions of the physical and technical variables are provided in table 1.[11-15] statistical analysis data were reported as means ± standard deviations. data normality was checked using the kolmogorov–smirnov test. a one-way analysis of variance (anova) was used to compare the physical and technical indicators of soccer players across five playing positions. the tukey hsd post-hoc analysis was further performed if the f-ratio was significant at p≤0.05. cohen’s effect size (d) was applied to examine the magnitude of the differences in the mean scores of the studied variables. effect size was classified as trivial (<0.20); small (0.20–0.59); moderate (0.60–1.19); large (1.20–2.00); and very large (>2.00).[16] all statistical analyses were conducted using the ibm spss version 26, armonk, ny: ibm corp. results table 2 shows the physical and technical indicators of football players according to playing position. regarding physical performance, central midfielders covered greater total distances compared to players in other positions. post-hoc comparisons using the tukey hsd test indicated the mean total distance for central midfielders was significantly (p < 0.05) different to that of central defenders (d = 1.79), wide defenders (d = 0.89) and forwards (d = 1.45). however, there was no significant (p>0.05) difference between the total distance covered by central midfielders and wide midfielders (d =0.20). contrary to other positions, central defenders recorded the lowest overall total distance. further, descriptive statistics indicated wide midfielders, wide defenders and forwards covered the greater distances while sprinting compared to central defenders (d = 1.19) and central midfielders (d = 0.95). concerning the technical variables, central midfielders table 1. operational definitions of physical and technical indicators variable definition physical indicators walking distance covered at a speed of 0–7 km.h-1 during a match. jogging distance covered at a speed of >7–14.5 km.h-1 during a match. running distance covered at a speed of >14.5–20 km.h-1 during a match. high-speed running distance covered at a speed of >20–25 km.h-1 during a match. sprinting distance covered at a speed of >25 km.h-1 during a match. total distance all distances covered during a match. technical indicators passes an intentional disposal of the ball with the aim to be received by a teammate. accurate passes (%) the percentage of passes which were actually received by a team. shots an attempt at goal, with the intention to score, made with any (legal) part of the body. crosses any ball played into the opposition team’s penalty area from a wide position. dribbles an attempt by a player in possession of the ball, to evade or move past an opponent while still in control of the ball. air challenges two players contesting for an aerial ball. air challenges won a player who wins an aerial ball after the contest between two players. tackles the act of gaining possession from an opposition player, when they are in possession of the ball. tackles won (%) the proportion of successful tackles, whereby a player removes the opposition from possession of the ball and possession is retained by either themselves or one of their teammates. lost balls loss of ball possession due to a mistake/poor control. fouls any infringement that is penalised as foul play by a referee. original research 3 sajsm vol. 33 no. 1 2021 played more passes compared to players in all the other playing positions. post-hoc analysis revealed that the mean value of passes for central midfielders was significantly (p < 0.05) different from that of the wide midfielders (d = 1.10) and forwards (d = 1.90). descriptive statistics indicated that the central defenders and central midfielders had a greater percentage of passing accuracy compared to wide defenders, wide midfielders, and forwards. the post-hoc analysis showed the mean percentage of passing accuracy for central midfielders was significantly (p < 0.05) different from that of the wide midfielders (d = 1.09) and forwards (d = 1.28). central defenders did not differ significantly (p > 0.05) from either the wide defenders (d = 0.42) or central midfielders (d = 0.11). in relation to crossing, wide defenders completed more crosses than players in other positions. interestingly, the mean crosses score for wide defenders was significantly (p < 0.05) different from that of wide midfielders (d = 0.62). when considering the loss of the ball, the results indicated that the forwards lost the ball on significantly more occasions than players in any of the other playing positions (p < 0.05). the post-hoc comparison showed the mean value of lost balls for forwards was significantly (p < 0.05) different from that of the central defenders (d =1.89), wide defenders (d = 1.25), central midfielders (d= 1.27) and wide midfielders (d = 0.60). the descriptive statistics indicated that while forwards were involved in more aerial challenges, central defenders won more aerial challenges than all other positions. in addition, forwards completed more dribbles than players in other playing positions. post-hoc analysis revealed that the average number of dribbles for forwards was significantly (p < 0.05) different from that of central defenders (d = 1.92), wide defenders (d = 1.02) and central midfielders (d = 0.95). finally, central midfielders, forwards and wide midfielders committed more fouls than central defenders and wide defenders. however, the post-hoc comparison indicated that central midfielders were significantly (p < 0.05) different from the central defenders (d = 0.81). discussion the current study aimed to investigate the physical and technical demands across individual positional roles during the 2019 conmebol copa américa football championship. the current observations showed the average total distance covered per match by south american players, irrespective of playing position, was 9 903 m, ranging from 7 534 m to 11 899 m. these results are lower than those reported by kubayi[4], who found that the overall distance covered by players during the uefa european football championship matches was 10 350 m, ranging from 8 446 m to 12 982 m. since these studies use the same observational methods to classify movements of the players during the game, it is proposed that matches at the copa américa tournament may require players to cover less distance compared to the more physically demanding european football championships. this finding is comparable with previous research, which reported that english premier league players covered significantly greater distances during matches than the south american players.[17] the differences in work-rate between the two groups may be a direct consequence of the tactical restrictions placed on the players because of the table 2. physical and technical indicators according to playing position central defenders (n = 45) wide defenders (n = 46) central midfielders (n = 50) wide midfielders (n = 17) forwards (n = 22) physical indicators walking (m) 3761 ± 252 3743 ± 232 3531 ± 254 3801 ± 300 3885 ± 409 jogging (m) 3620 ± 540 3792 ± 467 4249 ± 445 3911 ± 583 3405 ± 753 running (m) 1281 ± 268 1532 ± 287 1942 ± 414 1668 ± 376 1324 ± 330 high-speed running (m) 498 ± 137 710 ± 159 739 ± 202 796 ± 202 631 ± 165 sprinting (m) 67 ± 42 152 ± 199 91 ± 66 214 ± 170 138 ± 94 total distance (m) 9226 ± 720 9929 ± 633 10553 ± 763* 10390 ± 844 9383 ± 820 technical indicators passes 44.69 ± 19.28 49.67 ± 17.92 52.36 ± 15.12# 36.71 ± 13.22 28.23 ± 9.78 accurate passes (%) 86 ± 9 84 ± 7 8 ± 5# 79 ± 7 7 ± 9 shots 0.31 ± 0.60 0.30 ± 0.51 0.98 ± 1.22 1.41 ± 1.23 2.23 ± 1.57 crosses 0.00 ± 0.00 2.07 ± 2.02$ 0.38 ± 0.57 1.06 ± 1.14 0.68 ± 0.78 dribbles 0.31 ± 0.60 2.00 ± 1.73 2.06 ± 1.99 3.71 ± 2.66 4.50 ± 3.02¥ air challenges 4.78 ± 2.83 3.00 ± 2.01 3.80 ± 3.89 3.65 ± 3.33 7.64 ± 6.37 air challenges won 3.27 ± 1.98 1.43 ± 1.17 2.08 ± 2.10 1.59 ± 2.50 3.00 ± 3.15 tackles 2.51 ± 2.17 3.74 ± 2.27 4.74 ± 2.86 2.94 ± 1.68 2.09 ± 1.63 tackles won (%) 58 ± 40 63 ± 29 5 ± 28 56 ± 32 31 ± 34 lost balls 2.67 ± 1.80 5.09 ± 2.66 5.02 ± 2.58 7.76 ± 3.42 10.55 ± 5.60& fouls 0.91 ± 0.97 1.48 ± 1.09 1.94 ± 1.52€ 1.35 ± 1.27 1.73 ± 1.35 data are expressed as mean ± sd. unless a unit is provided, data are presented as counts. the following indicate significance (p<0.05): *significantly higher than central defenders, wide defenders and forwards; #significantly higher than wide midfielders and forwards; $significantly higher than wide midfielders; &significantly higher than all playing positions; ¥significantly higher than central defenders, wide defenders and central midfielders; €significantly higher than central defenders. original research sajsm vol. 33 no. 1 2021 4 different types of competition. in europe, the game is traditionally played at a fast pace and requires individuals to perform a high level of activity to receive the ball from a teammate or to pressurise opponents to regain ball possession. from a south american perspective, the tactical emphasis may be placed on producing quick decisive passing movements when an opportunity is presented or created. such tactical restraints reduce the need for players to be highly active when trying to regain possession of the ball and thereby may reduce their total distance covered.[17] while it was not an aim of this paper to make physical comparisons between international competitions, future research may consider exploring the different style of play across the two continents. when the various positional roles were compared, midfielders covered a greater distance per match compared to players in other positions. this finding corroborates previous findings which indicate midfielders cover greater distances per match due to their linking role in the team,[8] both with or without the ball, thus highlighting their indefatigable role associated with covering long distances during a match.[4] the finding in which wide defenders covered a larger total distance than central defenders and forwards is noteworthy. the tactical roles of wide defenders have evolved in modern soccer, as these players are required to operate in both attacking and defensive contexts.[2] this dual role can subject the player to greater overall efforts and may require them to have higher fitness levels than players in the role previously.[5] it is therefore important for soccer coaches and scientists to apply the concept of individual positional differences when conditioning players and to be linked to the playing style for players to meet the demands of the game. the present results showed that the players who sprinted for greater distances were wide midfielders, wide defenders, and forwards. a high demand for these movement patterns in attacking players (i.e. wide midfielders and forwards) is possibly as a result of the need to complete explosive moves away from defending players to create space or capitalise on goal scoring opportunities.[2] furthermore, previous studies have demonstrated the high-intensity activities (e.g. sprinting) completed by wide defenders may be due to playing tactics and dynamic formations,[10] whereby wide defenders contribute in the offensive phase of play; however, if there is turnover of possession, they must return quickly, especially through sprinting, to their defensive role.[2] the central midfielders covered the fewest metres in sprinting. this finding may reflect their tactical duties in which they must link the defence and offence which requires continuous running, rather than only explosive movements. it should also be noted, that depending on the team tactics, players in this position may not be required to find attacking positions, but rather contribute defensively and therefore, they reduce the amount of high-speed running required.[18] nevertheless, the current study indicates variations in highintensity movement patterns for different positions and therefore coaches should consider the development of training programmes according to individual playing roles (e.g. wide defenders). in line with previous studies,[5] smallsided games, which incorporate repeated sprint activities and intermittent exercises, may be developed to optimise the performance of soccer players. the present study indicated midfielders played significantly more passes compared to players in other positions. this result is expected, considering that teams build their attacks through the midfield central midfielders may be involved in transitions from defence to attack or attack to defence more than other players.[7] forwards, by contrast, had the lowest number of passes, which may be attributed to the specific role of forwards as they often have their backs to the goal during link-up play.[5] consequently, forwards may have limited options to pass the ball in contrast to central midfielders. another finding was that the central defenders had a greater percentage of accurate passes compared to players in other positions. this finding may reflect the tactics of teams to use the backline more effectively when adopting a possession-based style of play, such as playing out from the back.[10] in relation to crossing the ball, wide players delivered more crosses than any other player. this finding is not surprising given these players operate in wider positions on the pitch, which means that one of their main roles is to cross the ball into the box to create a goal-scoring opportunity. when considering the differences between these wide playing positions, it was interesting to note that wide defenders attempted significantly more crosses with moderate effect per match compared to wide midfielders. this demonstrates the evolving nature of the wide defender role in the modern game and the need to also to be effective in the attacking phases of play. it could also be inferred that south american teams are adopting formations/tactics which allow the wide midfielders to tuck inside during an attacking phase of play and encouraging wide defenders to move to the final third of the field to put a cross in the box. while exploring this style of play was not an aim of the current investigation, future research may consider the use of this overlapping tactic and how it may contribute to successful team performance. there was a significant difference in the number of dribbling actions completed across the playing positions, with forwards completing significantly more dribbling actions compared to the midfielders. this finding is inconsistent with that of taylor et al.[19] who found midfielders in europe performed the highest number of dribbles during a game. one of the roles for forwards is to penetrate the opposition defence to create goalscoring opportunities. one method to do this may be via dribbling at the defenders. a characteristic of the south american style of play is skill and flair, of which dribbling can be classified.[8] in contrast, central defenders completed the fewest number of dribbles per match, which may be attributed to the fact they tend to take fewer risks when in possession of the ball, as a mistake (i.e. of losing the ball to the opposition) can lead to a goal.[7] this perspective is also supported by the fact that defenders had the fewest number of lost balls per match. conversely, attacking players had the greatest number of lost balls. this is probably because attacking players take more risks when in possession of the ball as they attempt to penetrate the opposition’s defence, but they are also performing actions far from their own goal.[20] this result could original research 5 sajsm vol. 33 no. 1 2021 reflect the position of the forwards, as they are generally positioned in a dense zone on the pitch and are often outnumbered by the defenders. in addition to the numerical disadvantage, forwards usually play with their backs to the goal and receive the ball with a defender marking them. thus, it is generally difficult to control the ball and turn to the goal, whereas it is easier for the defender to intercept the ball when they are positioned at the front of the game.[20] in terms of the aerial element of the game, forwards and central defenders had the highest number of aerial challenges per match compared to that of any other position. however, when comparing their success rate, central defenders won a greater proportion of aerial duels compared to the forwards. this supports taylor et al’s[19] finding where defensive players have the highest number of clearances compared to that of attacking players. however, the low number of aerial duels won among forwards may be attributed to the fact they are often competing against the strongest defensive players on the opposition during aerial challenges.[7,19] consistent with previous research,[7] coaches should consider developing training sessions which incorporate heading exercises to respond to the demands of playing in both defensive and attacking positions. in addition, attacking players were found to have committed more fouls than defensive players. this may reflect the modern game, whereby players are encouraged to start defending from the opponent’s half by pressing to delay or interfere with the attack.[5] limitations and future research despite the novel information on physical and technical requirements across playing positions in south america investigated in this study, there are several limitations that should be considered. firstly, the study only analysed an available sub-sample (n = 13) of data from the 2019 copa américa. this may limit the generalisation of the findings to the whole tournament. secondly, while the current study has incorporated peer-reviewed published operational definitions of players’ movements, comparisons with other studies are limited due to different observational methods and classifications used across studies. finally, other variables, such as environmental factors, match outcome, the quality of the opposition, and the importance of the games were not assessed in the current study. therefore, future research may consider including a larger sample size and the effect of situational variables (e.g., match outcomes, playing formations, playing style, etc.) on the physical and technical performance of soccer players. conclusion the purpose of this study was to examine the physical and technical demands of football players according to positional roles at the 2019 copa américa tournament. the findings indicated that there are specific position variations in physical and technical demands. the knowledge gained from this study may allow for a greater understanding of the physical and technical requirements for football players in the copa américa and may have direct implications for devising match tactics. thus, football coaches should develop training programmes according to individual playing position, so players are prepared to meet their physical and tactical roles during a match. conflict of interest and source of funding: the author declare no conflict of interest and no source of funding. references 1. carling c, bloomfield j, nelsen l, et al. the role of motion analysis in elite soccer: contemporary performance measurement techniques and work rate data. sports med 2008; 38(10): 839–862. [doi: 10.2165/00007256-200838100-00004][pmid: 18803436] 2. di salvo v, gregson w, atkinson g, et al. analysis of high intensity activity in premier league soccer. int j sports med 2009; 30(3): 205–212. [doi: 10.1055/s-0028-1105950][pmid: 19214939] 3. bradley ps, di mascio m, peart d, et al. high-intensity activity profiles of elite soccer players at different performance levels. j strength cond res 2010; 24(9): 2343–2351. [doi: 10.1519/jsc.0b013e3181aeb163][pmid: 19918194] 4. kubayi a. evaluation of match-running distances covered by soccer players during the uefa euro 2016. s afr j sports med 2019; 31(1): 1–4. [doi: 10.17159/2078-516x/2019/v31i1a6127] 5. dellal a, chamari k, wong dp, et al. comparison of physical and technical performance in european soccer match-play: fa premier league and la liga. eur j sport sci 2011; 11(1): 51–59. [doi.org/10.1080/17461391.2010.481334] 6. rampinini e, impellizzeri fm, castagna c, et al. technical performance during soccer matches of the italian serie a league: effect of fatigue and competitive level. j sci med sport 2009; 12(1): 227–233. [doi: 10.1016/j.jsams.2007.10.002][pmid: 18083631] 7. ermidis g, randers mb, krustrup p, et al. technical demands across playing positions of the asian cup in male football. int j perform anal sport 2019; 19(4): 530–542. [doi: 10.1080/24748668.2019.1632571] 8. mclean s, salmon pm, gorman ad, et al. a social network analysis of the goal scoring passing networks of the 2016 european football championships. hum mov sci 2017; 57: 400– 408. 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[doi: 10.1080/02640414.2016.1230676] 19. taylor jb, mellalieu sd, james n. behavioural comparisons of positional demands in professional soccer. int j perform anal sport 2004; 4(1): 81–97. [doi: 10.1080/24748668.2004.11868294] 20. dellal a, wong dp, moalla w, et al. physical and technical activity of soccer players in the french first league-with special reference to their playing position. international sportmed journal 2010; 11(2): 278–290. original research 74 sajsm vol. 28 no. 3 2016 a survey of the attitudes and knowledge of parents of high school children on the east rand on the usage of nutritional supplements v van der walt, 1 mphil; y coopoo, dphil, facsm 2 1university of johannesburg, south africa 2head, department of sport and movement studies, faculty of health sciences, university of johannesburg, johannesburg, south africa corresponding author: v van der walt (violavanderwalt@icloud.com) the south african institute for drug-free sport introduced a campaign for school-going youth, indicating the risks to the youth when exposed to these supplements.[1] this, however, does not seem to be successful in preventing adolescents from using ns and exposing themselves to potentially contaminated products. any supplementary product ingested to boost the nutritional content of a normal diet to either fill a need or presumed deficiency, including any sportsor energy drink, tablets or injections, are deemed as ns for the purpose of this study. the gateway hypothesis suggests that possible future use of prohibited substances or drugs can be related to the previous use of legal ns, as drug use could follow a sequence of steps starting with so-called soft drugs. significant evidence exists about a relationship between the use of ns (fat burners, muscle builders), leading to the use of prohibited substances.[2] it is widely accepted that adolescent sports persons use various ns. this is confirmed in a study where 57% of johannesburg schoolboys used caffeine, 32% creatine and 54% carbohydrate supplements.[3] reasons for their use varied from assisting performance in sports to giving a sense of assurance of being selected for a specific team.[3] in a recent review, it was shown that at least 40-70% of athletes used ns, of which 10-15% may have contained prohibited substances.[4] nutritional supplements have no scientifically proven benefits in a healthy diet of an adolescent, but can contribute to children being overweight due to the high contents of sugar and carbohydrates,[5] increasing the risk of type 2 diabetes (t2d). studies which failed to accurately explain dehydration and its consequences, created an opportunity for marketing strategies targeting adolescents into believing that usage of ns is a necessity to enable high performance.[6] natural healthy foods such as fresh fruit and vegetables are viewed by parents as inadequate to fulfil dietary requirements of a growing athlete,[8] often resulting in young boys consuming excessive amounts of ns.[7] parental pressure and endorsement of ns contribute to their usage, to prevent being overlooked for possible success later on in the sporting world.[8] role models are also influential, as 57% of indian schoolboys in kwazulu-natal indicated that they felt pressurised by their bollywood idols to look stronger and bigger.[9] no studies, nationally or internationally, could be found covering the reasons why parents would endorse and even encourage the use of ns by their children despite there being a possible health risk. the primary aim of this study was therefore to determine the role and attitude of parents in their support and knowledge of ns, and at the same time, to determine to what extent they were aware of the health risks their children were exposed to. methods the use of quantitative (validated questionnaires)[3] and qualitative research (a focus group interview) types were selected to ensure collection of empirical evidence for background: the use of nutritional supplements (ns) by adolescents seems to be an escalating problem in south africa. any supplementary product ingested to boost the nutritional content of a normal diet to either fill a need or presumed deficiency, including any sports or energy drink, tablets or injections, are deemed as ns for the purpose of this study. parents seem to agree that children who play sport are allowed to use ns to assist them to perform better, without knowledge of the health risks associated with these products. despite information on websites and information sessions arranged by schools, parents seem to disregard advice given to them by experts. objectives: the objective of this study was to determine the attitudes and level of knowledge of parents of children on the east rand with regard to ns usage. methods: this was a cross-sectional study which used a previously validated, self-administered questionnaire for the parents (n = 198). it also included an interview with a focus group consisting of coaches and administrative staff (n = 9) representing each sports code selected for the purpose of this study. the data were analysed using largely descriptive statistics. results: nine percent of parents indicated that they considered themselves well informed with regard to ns; 13% indicated that they would support their children in obtaining ns without efficacy being proven and 75% indicated their awareness of the risk of ns being contaminated. coaches viewed the role of parents as integral regarding a healthy diet but indicated that the use of ns could not be ignored, also admitting to a lack in knowledge regarding ns. conclusion: parents and coaches demonstrated limited knowledge regarding ns. their knowledge was formed from information on labels and the internet. parents have a positive attitude towards the use of ns by their children despite indicating an awareness of the health risks related to ns usage. keywords: adolescents, presumed deficiency, nutrients, health risks, limited knowledge s afr j sports med 2016;28(3):74-78. doi: 10.17159/2078-516x/2016/v28i3a1674 http://dx.doi.org/10.17159/2078-516x/2016/v28i3a1674 original research sajsm vol. 28 no. 3 2016 75 statistical purposes. four high schools were invited to participate as a sample of convenience. the sports codes selected included rugby, cricket, hockey, netball and athletics. these sporting codes are regarded as those most likely to provide opportunities for children to pursue professionally in adulthood. questionnaires arrangements were made with the headmaster of each selected school for an information session to be held, on a prearranged date, with all the learners who take part in the selected sports codes, and who played for an open team (such as, 1st, 2nd) in the previous or current season. the learners were instructed to hand the sealed questionnaire to their parents for completion. parents were provided with information sheets and all signed a consent form.  the information sheet described the purpose of the study and the requirements for participation in the study. the questionnaire[3] had been validated in a previous study and was divided into four sections, namely, demographics, attitudes, information sourcing and ns usage.  participation would be voluntary and anonymous, and the data gathered would be discussed as trends and not as individual schools or persons.  one teacher at the school was selected as a drop-off point for the completed questionnaires.  a period of three weeks was allowed for completion. focus group the interview of the focus group was scheduled at a prearranged time and place that was convenient for all coaches to attend. twelve coaches and/or administrative staff involved with the selected sports teams were invited on a voluntary basis of which nine participants accepted. an open discussion was facilitated with the nine coaches, using a list of 10 questions as a guideline.  information sheets on the purpose of study and informed consent forms were given to the participants to read and sign beforehand.  data recovered from the recording were transcribed verbatim and organised into clusters of relevant themes. statistical analysis descriptive statistics were used to analyse the data obtained from the questionnaires. the data were group-analysed, based on specific sporting groups, gender, and age. the data obtained from the focus group utilised ‘atlas ti’ computer software to decipher the data which assisted in the transcribing and coding of the data. tape recorded interviews were transcribed verbatim and analysed so that codes could be assigned to repeated opinions by the focus group. results parents’ opinions and attitudes towards the use of ns and factors influencing the usage (table 1) a large group of parents (75%) indicated that they were aware of the risk that prohibited substances could contaminate ns, 68% agreed that the use of ns could act as a gateway drug and 92% indicated a substantial need for education programmes on ns. eighty-one percent of respondents indicated that the use of ns improved performance and 26% that their children needed the edge that ns added to the diet. some 28% indicated that pressure from coaching staff and teammates (30% used ns) were the main motivation for using ns, 45% claimed that better results were obtained with ns than with purely natural food and 34% indicated that the use of ns is a must despite a healthy diet. extent of nutritional supplements/medication usage by children with parental knowledge (table 2) most popular ns used: vitamins (63%), caffeine (36%) and protein supplements (35%). other substances used: alcohol over weekends (18%), anabolic steroids (17%), creatine (10%) and other recreational drugs, such as tik (crystal methamphetamine) and ecstasy (methylenedioxymethamphetamine (mdma)) (8%). fourteen percent of participants indicated that their children used medication for health reasons. sources of information most likely accessed regarding knowledge of ns (table 3) the internet was selected by 50% of participants, magazines (42%), followed by television (30%), friends and coaches (25% each), books (23%), newspapers (22%) and professional athletes (21%). gym instructors (15%), personal trainers, teachers and teammates (14%) were all used as sources. doctors (24%), pharmacists (20%), physiotherapists (13%) and biokineticists (12%) were also selected, saids was used by 10% and boksmart (4%) rated as the least accessed source. sources providing substances to children (table 4) these sources were mainly the pharmacist (27%), other team members (18%), friends (17%), coach (14%), gym trainer and fellow parent (11%). importance of parents’ role in the athletic triangle(table 5) sixty-eight percent of parents deemed their role as integral in the athletic triangle (coach, parent and athlete), 13% indicated their support of children in obtaining ns despite efficacy not proven. sixty-four percent indicated that their children relied on them for support and knowledge of ns, yet only 36% indicated awareness of an application for therapeutic use exemption (tue). only 18% of parents informed their child’s medical teams of medication usage. the importance of the role of the parent in the athletic triangle as well as the role of the coach as deemed by the coaching staff coaches indicated that children remained free to make their own choices and did not always listen to advice. they themselves often felt pressurised in ensuring that children performed well at the competitive level in order to be more eligible for bursaries. children did not seem to fear consequences of either positive testing or health risks regarding the usage of ns, therefore coaches deemed it imperative to work with the parents as a team. they indicated original research 76 sajsm vol. 28 no. 3 2016 a need to arrange for specialists in the field, such as dieticians, to present information sessions to the whole team and the parents. discussion it is significant that only 9% of parents indicated that they were well informed regarding ns when 64% indicated that their children relied on them for knowledge regarding the use of ns. the self-confessed lack of knowledge could be a good indication as to why children would use ns with table 1. attitudes, opinions of parents and factors influencing usage of ns factors influencing the attitudes and opinions of parents regarding the use of ns % yes (n/n) % no (n/n) attitudes parents feel sports bodies need to provide education 92 (180/197) 8 (17/197) parents deem usage of ns a must despite a healthy diet 34 (65/194) 66 (129/194) parents are aware of risk of contamination in ns 75 (149/198) 15 (30/198) parents are aware of usage of ns acting as a gateway drug 68 (135/198) 20 (40/198) parents are aware of teammates of children using ns 30 (60/198) 70 (138/198) opinions parents indicate usage of ns improves performance 81 (161/198) 19 (37/198) parents indicate better results are obtained with ns than with food only 45 (89/198) 55 (109/198) parents indicate coaches encourage usage of ns 28 (55/198) 72 (143/198) parents indicate usage of ns gives child the edge to perform 26 (51/198) 74 (147/198) n = sample size, n = number of responses table 2. nutritional supplements/drug used by children with parents’ knowledge nutritional supplement/ drug/medication usage % yes (n/n) % no (n/n) vitamin supplements 63 (114/180) 37 (66/180) caffeine tablets, red bull, etc. 36 (64/179) 64 (115/179) protein shakes 35 (63/179) 65 (116/179) alcohol over weekends 18 (33/181) 82 (148/181) anabolic steroids 17 (30/180) 83 (150/180) creatine 10 (19/182) 90 (163/182) other recreational drugs: tik, ecstasy, etc. 8 (8/105) 92 (97/105) medication for health reasons 14 (28/198) 86 (169/198) n = sample size, n = number of responses table 3. sources participants were most likely to access for information regarding nutritional supplements (n=198) source % yes (n/n) source % yes (n/n) internet 50 (98) gym instructors 15 (29) magazines 42 (83) personal trainers 14 (27) television 30 (60) teammates 14 (27) coach 25 (49) teachers 14 (27) friends 25 (49) physiotherapists 13 (25) doctor 24 (48) biokineticists 12 (24) books 23 (46) saids 10 (20) newspapers 22 (43) sports bodies 6 (12) professional athletes 21 (42) other 6 (12) pharmacist 20 (40) boksmart 4 (8) n = sample size, n = number of responses table 4. indicated sources providing substances to children as reported by parents source of substances % yes (n/n) % no (n/n) pharmacist without prescription 27 (20/74) 73 (54/74) pharmacist with prescription 23 (18/77) 77 (59/77) other team members 18 (11/60) 82 (49/60) friend 17 (13/76) 83 (63/76) coach 14 (10/73) 86 (63/73) fellow parent 11 (8/71) 89 (63/71) gym trainer 11 (8/72) 89 (64/72) n = sample size, n = number of responses table 5. importance of the parent’s role in the athletic triangle importance of parent’s role as deemed by the parent % yes (n/n) % no (n/n) does the parent deem a healthy diet without added ns as adequate? 73 (143/174) 16 (31/174) is the role of the parent deemed important in the athletic triangle? 68 (129/160) 16 (31/160) does your child rely on your support and knowledge of ns? 64 (125/175) 26 (50/175) does the parent support the child in buying ns? 13 (25/171) 75 (146/171) does the parent have knowledge of the application of therapeutic use exemption? 36 (72/198) 36 (71/198) does the medical team have knowledge of child’s medication usage? 18 (35/198) 28 (56/198) n = sample size, n = number of responses original research sajsm vol. 28 no. 3 2016 77 considering health risks and related side effects and parents’ guidance would clearly be inadequate due to their lack of knowledge. despite a lack of knowledge, 75% of parents were aware that ns held the risk of being contaminated, raising the possibilty that parents could be influenced by vigorous marketing strategies claiming results of unproven efficacies, using role models to sell products, and believing the information provided on the labels of products.[1] consumers were proven to be strongly influenced by the information given on labels of ns, as 70% believed claims of being free from contamination, 50% believed claims regarding the quality of the product and 40% believed the authenticity of the ingredients listed on the label.[10] coaches themselves admitted to having extremely limited knowledge regarding ns and believed that more expensive products were the more effective products. the medicines control council approved a new classification category for ns under the complementary medicines category, which places the burden of proof of efficacy and safety on the manufacturing company of that specific ns. companies have an extended period in which they are given the opportunity to produce proof for their claims, failing which the product has to be removed from the shelf.[11] this ammendment to the existing regulations could protect the parent regarding the product’s status pertaining to being free of health risks. it is difficult to understand why parents would allow their children to use ns when neither efficacy nor safety have been proven. in some scientific tests, 47% of the results of the 138 ns products tested revealed that the levels of melamine detected could have potentially lead to kidney stones and related renal health problems. melamine, in combination with other chemicals, also has the potential of causing health problems, yet it was not declared as an ingredient in any of the ns tested in this particular study.[12] craven week rugby players (u/19) that tested positive for the use of prohibited substances were found to be using at least four different ns simultaneously at any given time, adding up to the intake of a number of unknown chemicals that could be harmful to their long-term health.[8] companies which manufacture energy drinks repeatedly use marketing strategies aimed at creating a belief that extra ns are necessary. this creates a so-called ‘need-strategy’ to influence the consumer into believing that it is essential for these drinks to be taken during exercise.[6] up to 50% of the energy drink market consists of children, adolescents and young adults using energy drinks which are high in caffeine levels.[5] they also have related long-term health risks , such as, seizures, cardiac abnormalities and t2d.[5] parents were of the opinion that energy and sports drinks were harmless and that children needed them to hydrate during participation in sports. coaches indicated that children often psychologically relied on energy and sports drinks during training sessions. twenty-five percent of parents indicated that they relied on coaches for guidance regarding ns, and 14% indicated that the coaches themselves were often the suppliers of ns. the question arises as to whether coaches have the best interests of the sports-playing child at heart given the fact that in this study they themselves admitted to be positively inclined towards the use of ns. the athletic triangle should interact with one another resulting in a complementary and harmonising relationship between coach and parent as this has a critical affect on the participation of the sports child.[14] parents clearly feel the need to be better informed regarding ns as 92% indicated a demand for education programmes. in this study the main source of information utilised was the internet (50%), with saids used by only 10% and boksmart only by 4%. saids seem to be reaching the people concerned with sports (coaches, etc.) but does not have a great impact on parents. furthermore, medical professionals, such as doctors, were used by only 24% of parents, 13% used the physiotherapists and 12% the biokineticists. this study seems to indicate that the parents are not consulting credible sources for information regarding ns. parents indicated that sources of substance supply were mainly the pharmacists (27%) followed by team members (18%). recently, a leading group of pharmacists agreed to form an alliance with the ‘informed-sport’ and ‘informed-choice’ campaigns which call for ns to be tested by the laboratory of the government chemist.[13] fairweather[13] explained that ‘informed-choice’ entails the testing of a random selection of ns off the shelves over a period of 12 months for potential contamination and mislabelling, whereas ‘informed-sport’ tests samples from every batch that is sold from the shelves. these actions, nevertheless, do not provide a 100% safety guarantee of these products as there could still be single containers which have not been tested and are potentially contaminated.[13] very limited studies nationally and internationally could be found regarding the role of parents and the use of ns by their children. the athletic triangle describes the importance of the role of the parents regarding knowledge of the child’s chosen sports and this is seen as an integral part of the eventual enjoyment of sports by the child, which should be the main goal of participation.[14] no scientific evidence is available to substantiate the parent’s view that a diet consisting of natural fruits and vegetables, together with all the other requirements expected from natural foods, is inadequate.[8] a leading dietitian in the field who tried to educate parents on how to purchase healthy foods in the store concluded that parents avoided this responsibility as they lacked the knowledge required, largely as their own lifestyles were unhealthy.[7] therefore children reverted to easy way out of this dilemma by turning to ns.[7] it was found that paternal behaviour, influenced by personal conviction, plays an important role in the protection of their children from doping.[15] this finding could be very significant in achieving a change of attitude in parents and therefore ultimately having a significant influence on the child’s attitude towards the use of ns. it is suggested that fathers should be encouraged to utilise their communication skills to influence their children regarding the potential dangers of doping.[15] furthermore, the importance of education should be emphasised and focus on the positive role of nutrition, including all role players involved with the child athlete.[16 original research 78 sajsm vol. 28 no. 3 2016 study limitations there are always limitations with respect to the answering of a questionnaire, i.e. the loss of meaning, misunderstanding the intent of the question, participants not being utterly truthful or the determination of how much thought went into the responses. the researcher, however, has tried to ensure the integrity of the results’ interpretation. conclusion in this study, parents showed a severe lack of knowledge regarding the efficacy and related potential health risks with regard to ns and based their choices mostly on knowledge gained from information given on the internet. they indicated a dire need for educational programmes. the south african institute for drug-free sport seems to have made little impression on parents as a source of information as only ten percent accessed this source of information. parents relied mainly on inaccurate sources, such as the internet and coaches for knowledge, despite coaches also admitting to having very limited resources regarding information and knowledge of ns. coaches and parents acknowledged the importance of the role that parents play in respect of their involvement in the athletic triangle. both parents and coaches exercise influence on the child’s attitudes regarding ns and at present they all seem to hold a positive attitude towards ns believing that their use is more beneficial than harmful. recommendations the responsibility to inform parents and children lies with all specialists and experts involved in the field of sports. more emphasis should be given to the nutrition of sportspersons through training and educational programmes by all professionals involved physiotherapists, sports scientists, dietitians, etc. schools should be encouraged by means of incentives to make use of the educational programmes offered by saids, with coaches taking responsibility for this avenue of enrichment, as they are the entitiy closest to both the child playing sport and the parents. the attainment of knowledge should be updated or renewed on a regular and long-term basis. this should start at primary school level and continue into high school, as children’s needs change as they grow older. the formation or the change of attitudes of individuals are easily influenced by someone else deemed to be a role model and displaying a good self-esteem. attitudes can also be changed when new ideas are acknowledged by a person regarded as knowledgeable.[17] these tools can be used more effectively to bring about new and more informed attitudes regarding ns when arranging information sessions for parents. professional athletes should not be utilised only as motivational speakers but also as role models to exercise influence in respect of healthy diets. the athletic triangle as a unit should be born in mind at all times as no entity is more important than the other. the role of the parent should be maintained and emphasised at all times and parents should be made aware of the importance of their contribution to this relationship. the sense of ethics in training an athlete in an honourable and healthy manner should be impressed upon both coaches and parents alike – never forgetting that the main aim of junior sports should be enjoyment and development of skills. in fact, this should be expected from all professionals involved in the well-being of a growing child. acknowledgements: the researchers would like to thank all participants from the high schools for their extremely important contribution to this study. references 1. south african institute of drug free sport. position statement of the south african institute of drug free sport on the use of supplements in sport in school-going youth, 2011. http://www.sasma.org.za/articles/saids%20statement%20for%20youth. pdf (accessed 17 november 2013) 2. hildebrandt t, harty s, langenbucher jw. fitness supplements as a gateway substance for anabolic-androgenic steroid use. psychol addict behav 2012;26(4):955-962. [http://dx.doi.org/ 10.1037/a0027877] 3. gradidge p, coopoo y, constantinou d. attitudes and perceptions towards performance enhancing substance use in johannesburg boys high school sport. s afr j sports med 2010;22(2):32-36 4. outram s, stewart b. doping through supplement use: a review of the empirical data. int j sport nutr exerc metab 2015; 25(1):54-59 5. seifert sm, schaechter jl, lipshultz se, hershorin er. health effects of energy drinks on children, adolescents, and young adults. j pediatr 2011;127(3):511-528. [http://dx.doi.org/ 10.1542/peds.2009-3592] 6. noakes t. waterlogged: the serious problem of overhydration in endurance sports..champaign, il: human kinetics, 2012:147-181 7. de villiers n. how to decide if you need a supplement and if it is safe and effective? poster session presented at: south african sports medicine association congress; 2015 october 19-22; sandton, sa 8. claassen, a. educational resources and updated position statement. poster session presented at: south african sports medicine association congress; 2015 october 19-22; sandton, sa 9. martin j, govender k. making muscle junkies: investigating traditional masculine ideology, body image discrepancy, and the pursuit of muscularity in adolescent males. int j mens health 2011;10(3):220-239. [http://dx.doi.org/ 10.3149/jmh.1003.220] 10. gabriels g, lambert m. nutritional supplement products: does the label information influence purchasing decisions for the physically active? nutr j 2013;12:133. [http://dx.doi.org/ 10.1186/1475-2891-12-133] 11. meltzer s. making sense of a supplements label. poster session presented at: south african sports medicine association congress; 2015 october 19-22; sandton, sa 12. gabriels g, lambert m, smith p, et al. melamine contamination in nutritional supplements is it an alarm bell for the general consumer, athletes, and "weekend warriors"? nutr j 2015;14:69. [http://dx.doi.org/ 10.1186/s12937-015-0055-7] 13. fairweather c. addressing top contentious questions around dietary and sport supplements. discussion session presented at: south african sports medicine association congress; 2015 october 19-22; sandton, sa 14. smoll fl, cumming sp, smith re. enhancing coach-parent relationships in youth sports: increasing harmony and minimizing hassle. int j sports sci coach 2011;6(1):13-26. [http://dx.doi.org/ 10.1260/1747-9541.6.1.13] 15. blank c, leichtfried v, muller d, et al. role of parents as a protective factor against adolescent athletes' doping susceptibility. s afr j sports med 2015;27(3):87-91. [http://dx.doi.org/ 10.7196/sajsm.8094] 16. duvenage km, meltzer st, chantler sa. initial investigation of nutrition and supplement use, knowledge and attitudes of under-16 rugby players in south africa. s afr j sports med 2015;27(3):67-71. [http://dx.doi.org/ 10.7196/sajsm.8092] 17. katz d. the functional approach to the study of attitudes. public opin q 1960; 24(2):163-204. [http://dx.doi.org/ 10.1086/266945] http://www.sasma.org.za/articles/saids%20statement%20for%20youth review 1 sajsm vol. 35 no. 1 2023 creative commons attribution 4.0 (cc by 4.0) international license management of lumbar bone stress injury in cricket fast bowlers and other athletes jw orchard,1 md, phd; r saw,2 mbbs, facsep; a kountouris,3 phd; d redrup,4 mphty; p farhart,5 mhs; k sims,6 phd 1 school of public health, university of sydney, australia 2 australian institute of sport, act, australia 3 lasem research centre, latrobe university, australia 4 cricket nsw homebush new south wales, australia 5 school of sport, exercise and rehabilitation, university of technology, sydney, new south wales, australia 6 school of health and rehabilitation sciences, university of queensland, australia corresponding author: jw orchard (john.orchard@sydney.edu.au) lumbar bone stress injuries (lbsi) have been recognised as a common cause of back pain in cricket fast bowlers and other athletes for at least 40 years.[1] spondylolysis (including active lbsi and chronic pars defects) has been reported to occur in up to 44% of professional athletes, which is significantly more common than in amateur athletes and non-athletes. [2] spondylolysis has consistently been found to be the most common cause of back pain in young athletes.[3] the recognition and management of lbsi has evolved with improvements in research and knowledge, plus in part, with improvements in medical imaging. [4] over the time period from the 1980s to the present, there have been substantive advances in imaging (see table 1). when x-ray was the only available imaging modality, lumbar stress fractures (spondylolysis) were only visible when they had already occurred and then failed to heal. further to this, if they become bilateral they might lead to spondylolisthesis (slippage), also visible on x-ray. spondylolisthesis was graded 1-3 on x-rays and grade 3 slips were relatively common in athletes in years prior to 2000.[5] whilst the introduction of computerised tomography (ct) scanning allowed easier identification of the cortical breach lbsi of the pedicle and pars interarticularis, it is important to note that ct possesses reduced sensitivity in diagnosing noncortical breach lbsi (stress reactions).[6] the introduction of nuclear imaging, known as single photon emission computed tomography (spect) allowed stress reactions and prefracture pathology to be identified as ‘hot spots' in the 1990s and 2000s. more recently, mri assessment using bone window sequences (such as volumetric interpolated breath-hold examination (vibe)) has become the preferred form of imaging.[7] back pain in middle-aged adults it is important to consider that lumbar stress fractures are one of many causes of back pain, with an important distinction that lumbar stress fractures almost always affect athletic teenagers and young adults, whereas back pain itself is a common symptom at all ages. despite the advances in lumbar imaging, background: recent guidelines (including a special series in the lancet) have emphasised a minimal role for imaging when assessing low back pain in adults, as the majority of patients will have non-specific findings on imaging that do not correlate well with pain. objective: to assess whether the diagnosis of lumbar bone stress injuries in young athletes should be considered an exception to the recommendation to avoid imaging for low back pain in adults. method: narrative review. results: early lumbar bone stress injury diagnosis has been available via traditional mri sequences (and its precursor single photon emission computed tomography (spect)) for 25-30 years. mri assessments using bone window sequences (such as volumetric interpolated breath-hold examination (vibe)) have allowed a better understanding of the diagnosis and prognosis of lumbar bone stress injury in young athletes. mri with bone sequences has allowed non-radiating scans to serially follow the healing of unilateral stress fractures. in the majority of cases, non-chronic unilateral fractures can heal; however, this takes threesix months rather than the six-ten weeks that would be the typical unloading period if using symptoms (only) as a guide. the use of mri to provide evidence of bony healing (as opposed to fibrous union, which creates the pars defect that predisposes to further bone stress lesions) can lead to better long-term outcomes in athletes. there is evidence to flag this as a structural lesion which is both painful and, more importantly, can heal/resolve if managed correctly. therefore it represents an important ‘specific’ diagnostic subset within adult low back pain. conclusion: structural (rather than functional) management of bone stress injuries in high-demand athletes, such as cricket pace bowlers, is in contrast to the recommendation of functional management for general back pain in adults. structural management is justified when there are demonstrable superior outcomes of having better structure. although this has not yet been shown in randomised trials of elite athletes, apparent lengthier test cricket careers of pace bowlers who do not have pars defects suggest better athletic outcomes if bony healing is achieved. for lower demand young adults, or athletes with established bilateral pars defects, functional management may be more pragmatic. keywords: lumbar spine, stress fracture, spondylolysis, spondylolisthesis, cricket, fast bowling, bone marrow oedema s afr j sports med 2023;35:1-6. doi: 10.17159/2078-516x/2023/v35i1a15172 mailto:john.orchard@sydney.edu.au http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15172 https://orcid.org/0000-0001-9604-3221 https://orcid.org/0000-0003-3530-1711 https://orcid.org/0000-0002-8637-1392 https://orcid.org/0000-0002-8237-895x https://orcid.org/0000-0002-2144-9179 https://orcid.org/0000-0003-4518-466x review sajsm vol. 35 no. 1 2023 2 there is widespread evidence to show that this has not led to an overall improvement in the management of back pain in adults.[8, 9] the importance of imaging (of back pain in most adults) is to rule out ‘sinister’ causes, such as tumours or conditions leading to significant neurological compromise. these conditions are uncommon and are visualised in less than 5% of lumbar scans (including 3d imaging, such as ct and mri). in the vast majority of middle-aged or older adults, substantial lumbar mri changes will be present in most of the population and represent ‘normal age-related (degenerative) changes’. they do not correlate well with back pain, being present in asymptomatic people (of the same age) and generally as often as in symptomatic patients. the presence of old fibrous unions (pars defects) from unhealed stress fractures in youth are an example of imaging findings in middle-aged adults that may not correlate with symptoms. for this reason, unless there are ‘red flag’ symptoms which alert to the possibility of sinister pathology, most guidelines recommend avoiding imaging in uncomplicated middle-aged back pain. the concern in middle-aged patients is that exercise is usually the most evidence-based treatment modality for back pain, but there is the tendency for patients to avoid loading if they have been told they have degenerative changes on scan, such as disc degeneration and prolapses. when medical imaging is performed, the practitioner should explain what findings are relevant, and which findings are likely to be ‘normal’ for the person’s demographic. natural history of stress fractures in the x-ray era prior to the 2000s, most fast bowlers in their late teenage years sustained a lumbar stress fracture, or more than one, and generally, they did not take much time off. the vast majority ended up with chronic fibrous unions. spondylolysis was so common that in the early 1980s, a cohort of senior victorian squad members was assessed with x-rays, which found 11 out of 12 pace bowlers had x-ray evidence of unilateral or bilateral pars defect +/spondylolisthesis.[10] in the early 1990s, a cohort of junior western australian fast bowlers (mean age of 17) exhibited a prevalence of 55% for the presence of a spondylolisthesis or pars defect.[11] some of the bowlers from this era coped well, others had chronic niggling back pain for their entire career, with a reduced ability to bowl at extreme pace, and a small percentage needed to retire. spondylolysis and spondylolisthesis are also very common amongst athletes in other sports.[9, 12] specialist management of stress fractures in the ct/bone scan era the emergence of the ct scan (3d imaging) and bone scan (functional assessment of bone stress), combined as spect-ct, allowed a much earlier diagnosis of lumbar stress fractures from the 1990s onwards. the net result of this was that high grade (2 or 3) spondylolisthesis in athletes became a less common occurrence, as athletes were encouraged to rest upon a diagnosis of an acute painful stress fracture. generally, rest/unloading was prescribed until symptoms resolved, which was usually a period of 6-10 weeks. although high grade spondylolisthesis becomes less common, spondylolysis (pars defects) did not appear to be eliminated by the routine use of the ct scan.[13] because there is a high amount of radiation associated with spect-ct, it was difficult to justify follow-up scans to monitor for a bony union. lumbar bone stress injuries and consequent non-unions remained high in this era.[14] management options of bone stress injury in the mri era treatment options in the mri era have expanded now that tools are available to assess the presence, extent and intensity of bone marrow oedema within the posterior elements of lumbar vertebrae.[15] mri sequencing techniques have developed further in recent years with the advent of special bony windows (thin slice three-dimensional t1-weighted radiofrequency spoiled echo sequences, including volumetric interpolated breath-hold examination (vibe) sequence) and have allowed ‘ct-like’ bony imaging with mri.[7] one study found mri with vibe sequences to be 98% sensitive and 92% specific for the diagnosis of lbsi compared to ct.[6] poor quality mri images without the correct sequencing protocols can lead to misdiagnosis and mismanagement from the outset. radiologists and mri technicians with considerable experience in the imaging of lbsi are preferred. an mri protocol should include a heavily water weighted sequence, such as a short-tau inversion recovery (stir) sequence, to detect bone oedema, along with a fine-slice vibe or equivalent sequence to assess for a fracture.[7] the major advance has been the ability to follow serial mri scans to monitor for the resolution of bone oedema and bony healing given that radiation is not a concern.[16] resolution of bone oedema correlates well with bone healing on ct, and resolution of clinical symptoms. [17] another study found mri with vibe sequencing can be used to monitor table 1. imaging options in athletic back pain over the past 50 years imaging modality advantages/disadvantages of imaging time frame/ availability plain x-ray with oblique views able to see chronic changes (only) including pars defects and spondylolisthesis. cheap. available from 2nd half of 20th century. ct scan with spect able to visualise acute bone stress (nuclear medicine component) and 3d structural bone defects (ct component). relatively high levels of radiation involved. available from 1990s mri scan with appropriate sequencing (stir or equivalent to identify bone oedema, and vibe or equivalent to assess for fracture line) able to visualise acute bone stress and 3d structural bone defects (from bone sequences). nonradiating so can be safely repeated bone sequences have been available from 2010s spect, single photon emission computed tomography; mri, magnetic resonance imaging; stir, shorttau inversion recovery; vibe, volumetric interpolated breath-hold examination. review 3 sajsm vol. 35 no. 1 2023 healing in cricketers, and that recurrent fractures take longer to radiologically unite. [18] bone stress injury without fracture bone stress injury, as demonstrated on mri, without any cortical breach (as seen on a bone sequence view of an mri or ct scan) is a condition to be treated with caution. it is known that this is a precursor lesion to an actual fracture, so that an athlete who continues to load without a fracture is at high-risk of progression to a fracture.[16, 19] where there is a desire from the athlete to return to ‘high-risk’ activities such as cricket pace bowling, a follow-up mri after a period of unloading can hopefully demonstrate the return of signal ratios to normal levels, after which time it may be considered safe to resume training. [15] early diagnosis of unilateral acute stress fractures when managing lbsi in australian pace bowlers, our current approach in most situations is to not allow a return to bowling until the mri scan (with vibe bony window sequence) shows complete bony healing.[4] most of the time this can be achieved if the fracture (usually on the contra-lateral side to the bowling arm side) is picked up early enough [18] however, we generally find that it takes 4-6 months to get complete resolution.[4] an argument in favour of this approach has been our current stock of test bowlers, who have generally been managed this way (early mri imaging and then unload until structural healing occurs) on multiple occasions to achieve bony union. australian test bowlers are required to, and generally can, bowl through high workloads at high pace. we are aware that the cohort level of evidence is not as strong as randomised trial evidence, but also that other experts take a similar approach to management internationally.[20] while obtaining a highquality mri scan at the point of initial unilateral partial stress fracture has facilitated a process to allow many fast bowlers to achieve bony union, it is certainly not a miracle cure. getting bony union requires many months off bowling (usually a full season) and results in some secondary temporary loss of bone density,[21] meaning that recurrent stress fractures the following year are also common. recurrent stress fractures also appear to take longer to achieve bony healing.[18] therefore, in the event of finding a stress fracture very early, it is sometimes a difficult decision for the athlete to take a long period of time off sport in the hope of better results down the track. this decision is easier to justify in the aspiring test bowler, but can become more difficult in t20-focused bowlers, amateur players, nonbowlers and in other sports with lower demands, where the long-term benefits of superior bony union may be less relative to the downside of a long layoff period. ages from 23.1 to 24.9 years have been reported as the 95% confidence interval for the attainment of peak bone mineral density in males [22], and if you can make it to this age without any established spondylolysis or spondylolisthesis, it seems to benefit the fig. 1. flowchart summary. the bordered section represents scan recommendations from adult guidelines for low back pain.[8] we propose that a sub-section of adults (young athletes) needs further consideration of scan requirements, as structural management in this subgroup can lead to improved results. a unilateral “hot” stress fracture is one with bone marrow oedema around an acute fracture line, which has the potential to heal if unloaded.[18] review sajsm vol. 35 no. 1 2023 4 second half of an athletic career. in particular, we have not seen as many cases of bowlers requiring premature retirement due to chronic back pain in the modern era compared to the 1980s, 1990s and 2000s. in the post-athletic career, almost the entire population will have significant degenerative changes in the lumbar spine by middle age.[23] there is no clear evidence to say that those who suffered lumbar stress fractures in youth have any more back pain in middle-age than those who didn’t. some studies have shown equivalent or better pain in middle-age between retired athletes and the general population, including athletes with spondylolysis and spondylolisthesis.[9, 24] bilateral stress fractures when there is an established non-union in the pedicle or pars interarticularis contralateral to the bowling arm side, a stress fracture to the ipsilateral side, that is the bowling arm side, appears more likely to occur, often in the pedicle. bony healing remains desirable, but even with prolonged rest and optimal management, this outcome may not occur in the presence of an established non-union on the other side.[25-27] a chronic lesion that is very unlikely to heal can be managed more pragmatically with a return to activity as pain allows. treatment is generally then ‘functional’ (taking a shorter period of time off in line with pain flare-ups) rather than structural, with the concession that there may be limits on workload tolerance or pace in the longer term. very occasionally, surgery can be indicated with bilateral lesions leading to chronic pain which prevent bowling at the desired level.[28] because of the high morbidity associated with surgery, this is usually only an option when retirement is being considered (i.e. that surgery should not be considered routine but is instead a career-saving procedure). use of bracing thoracolumbar spine bracing has often been included as part of the traditional specialist management protocol of spondylolysis,[29] although recommendations for bracing are not universal.[30] while the application of a brace to limit lumbar extension and rotation logically should promote healing, there is a lack of strong evidence to support a clear advantage in all athletes. a meta-analysis of the conservative management of spondylolysis with grade 1 spondylolisthesis did not find a difference on return to sport or clinical outcomes for those treated with or without a brace.[31] there may be benefit for specific individuals from encouraging or enforcing unloading from sport. there may be a subset of athletes that are more likely to benefit from bracing, including those with persisting pain at rest, exaggerated lumbar lordosis, clinical factors making delayed or non-union more likely, or bilateral stress fractures.[31] in practice, we generally do not prescribe braces for full-time athletes. the “real-world” advantage of bracing may be in the schoolkid who might still play hours of casual twisting sport at school (without a brace) even despite agreeing to refrain from formal sporting competition. with an initial diagnostic management protocol and enforced unloading +/bracing, good functional results can be achieved in a majority of cases, but it is also to be expected that spondylolysis defects will persist in a high percentage of athletes.[29] indication for mri scan figure 1 and table 2 can assist with the diagnostic approach for back pain in the young athlete. the most difficult question to start with is which athletes with back pain warrant an mri scan. our view is that an mri scan should be used when the yield is high for finding the lesion which may be amenable to table 2. recommended management protocols for lumbar bone stress lesion in the young athlete management protocol imaging requirements management consequences recommended utility functional [8] nil refrain from sport when in pain, but graded return to play as soon as pain settles many lumbar stress fractures will remain unconfirmed; risk of spondylolisthesis if heavy loading persists when fracture is not healed this protocol reflects guidelines for back pain in middle-aged people; appropriate in young adults who have low sporting demands traditional conservative treatment (pain management) [29] spect-ct or mri for diagnosis 6-10 week (approx.) of dedicated unloading +/bracing after diagnosis of acute stress fracture lumbar stress fracture diagnoses will be made. healing is not generally monitored so recurrence, pars defects and spondylolisthesis may be more likely. may be appropriate where the athlete prefers a faster return to sport, and acknowledges the higher risk of long term consequences. less recommended for ‘high risk’ athletes bony-healingdependent conservative treatment (structural management)[4, 20] mri for diagnosis and serially to demonstrate bony healing unloading from all high-risk activities until full bony healing is demonstrated (usually 4-6 months) or the nature/progress shows that bony healing will not occur bony healing can be achieved with early (unilateral lesion) diagnosis recommended in the majority of high-level athletes. in particular those at greater risk of complications (recurrence, pars defects, spondylolisthesis) which could negatively impact on their athletic career spect, single photon emission computed tomography; mri, magnetic resonance imaging review 5 sajsm vol. 35 no. 1 2023 healing, in the athlete who would be prepared to undertake the necessary unloading to allow healing. in the sport of cricket, young pace bowlers with contra-lateral side back pain associated with bowling generally represent a high yield population for which an early scan provides value.[32] in the same sport, specialist batters who do not bowl (or play any other twisting sport) are far less likely to have bone stress lesions and hence do not usually warrant early referrals for an mri scan. different sports will have varying yields for early scans. a recent review in the sport of baseball found that laterality in pain that lasted for over 4 weeks, which interfered with running and with spinous process tenderness were the characteristics most associated with spondylolysis.[33] conclusion management of lumbar bone stress injury is complicated as there are no clear pathways that can be directed by level 1 evidence. randomised control trials in elite athletes are very difficult to conduct, and we believe that elite athlete management needs to be different for the general community (e.g. table 2, figure 1). the trend towards managing back pain with a functional approach makes sense in low-demand young athletes, but we strongly believe that it risks career-shortening in high-level young athletes. in this group, which includes cricket fast bowlers, we advocate a structural approach.[4] conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: we would like to acknowledge, beyond this author group, all the physiotherapists and sport and exercise physicians who have worked in australian cricket in this time period, many of whom have contributed to the development of our current approach. author contributions: jwo as lead author wrote the initial draft of this narrative review, after a discussion of the article concept with rs. all other authors (ak, dr, pf, ks) returned suggested mark-up edits and requested additions of particular references. all authors in this group have contributed conceptually over 20 years to the current approach to the management of these injuries in australian pace bowlers. references 1. annear pt, chakera tm, foster dh, et al. pars interarticularis stress and disc degeneration in cricket's potent strike force: the fast bowler. anz j surgery 1992 oct;62(10):768-773. [doi: 10.1111/j.1445-2197.1992.tb06915.x. eng] 2. sakai t, sairyo k, suzue n, et al. incidence and etiology of lumbar spondylolysis: review of the literature. j orthop sci 2010 may;15(3):281-288. [doi: 10.1007/s00776-010-1454-4. eng] 3. wall j, meehan wp, 3rd, trompeter k, et al. incidence, prevalence and risk factors for low back pain in adolescent athletes: a systematic review and meta-analysis. br j sports med 2022 nov;56(22):1299-1306. [doi: 10.1136/bjsports-2021-104749] 4. kountouris a, saw r, saw a. management of lumbar spondylolysis in athletes: role of imaging. current radiology reports 2018;6:39. [doi: https://doi.org/10.1007/s40134-018-0299z] 5. stinson jt. spondylolysis and spondylolisthesis in the athlete. clin sports med 1993 jul;12(3):517-528. 6. ang ec, robertson af, malara fa, et al. diagnostic accuracy of 3-t magnetic resonance imaging with 3d t1 vibe versus computer tomography in pars stress fracture of the lumbar spine. skeletal radiol 2016 nov;45(11):1533-1540. [doi: 10.1007/s00256-016-2475-7. eng] 7. koh e, walton er, watson p. vibe mri: an alternative to ct in the imaging of sports-related osseous pathology? br j radiol 2018 jul;91(1088):20170815. [doi: 10.1259/bjr.20170815. eng] 8. hartvigsen j, hancock mj, kongsted a, et al. what low back pain is and why we need to pay attention. lancet. 2018 jun 9;391(10137):2356-67. [doi: 10.1016/s0140-6736(18)30480-x eng] 9. schmitt h, brocai dr, carstens c. long-term review of the lumbar spine in javelin throwers. j bone joint surg br 2001 apr;83(3):324-327. [doi: 10.1302/0301-620x.83b3.11386. eng] 10. payne w, carlson j, hoy g, et al. what research tells the cricket coach. sports coach 1987;10:17-22. 11. elliott b, hardcastle p, burnett a, et al. the influence of fast bowling and physical factors on radiologic features in high performance young fast bowlers. sports medicine, training and rehabilitation 1992;3(2):113-130. 12. külling fa, florianz h, reepschläger b, et al. high prevalence of disc degeneration and spondylolysis in the lumbar spine of professional beach volleyball players. orthop j sports med 2014 apr;2(4):2325967114528862. [doi: 10.1177/2325967114528862. eng] 13. millson hb, gray j, stretch ra, et al. dissociation between back pain and bone stress reaction as measured by ct scan in young cricket fast bowlers. br j sports med 2004 oct;38(5):586-591. [doi: 10.1136/bjsm.2003.006585. eng] 14. johnson m, ferreira m, hush j. lumbar vertebral stress injuries in fast bowlers: a review of prevalence and risk factors. phys ther sport 2012;13(1):45-52. 15. sims k, kountouris a, stegeman jr, et al. mri bone marrow edema signal intensity: a reliable and valid measure of lumbar bone stress injury in elite junior fast bowlers. spine (phila pa 1976) 2020 sep 15;45(18):e1166-e1171. 16. kountouris a, sims k, beakley d, et al. mri bone marrow oedema precedes lumbar bone stress injury diagnosis in junior elite cricket fast bowlers. br j sports med 2019 oct;53(19):12361239. [doi: 10.1136/bjsports-2017-097930. eng] 17. sakai t, sairyo k, mima s, et al. significance of magnetic resonance imaging signal change in the pedicle in the management of pediatric lumbar spondylolysis. spine (phila pa 1976). 2010 jun 15;35(14):e641-645. [doi: 10.1097/brs.0b013e3181c9f2a2. eng] 18. singh sp, rotstein ah, saw ae, et al. radiological healing of lumbar spine stress fractures in elite cricket fast bowlers. j sci med sport 2021 feb;24(2):112-115. [doi: 10.1016/j.jsams.2020.06.018. eng] 19. taylor j, saw ae, saw r, et al. presence of bone marrow oedema in asymptomatic elite fast bowlers: implications for management. bone 2021 feb;143:115626. [doi: 10.1016/j.bone.2020.115626. eng] 20. kasamasu t, ishida y, sato m, et al. rates of return to sports and recurrence in pediatric athletes after conservative treatment for lumbar spondylolysis. spine surg relat res 2022 sep 27;6(5):540544. [doi: 10.22603/ssrr.2021-0242. eng] 21. alway p, peirce n, johnson w, et al. activity specific areal bone mineral density is reduced in athletes with stress fracture and requires profound recovery time: a study of lumbar stress fracture in elite cricket fast bowlers. j sci med sport 2022 oct;25(10):828-833. [doi: 10.1016/j.jsams.2022.08.006. eng] review sajsm vol. 35 no. 1 2023 6 22. xue s, kemal o, lu m, et al. age at attainment of peak bone mineral density and its associated factors: the national health and nutrition examination survey 2005-2014. bone 2020 feb;131:115163. [doi: 10.1016/j.bone.2019.115163. eng] 23. wocial k, feldman ba, mruk b, et al. imaging features of the aging spine. pol j radiol 2021;86:e380-e388. [doi: 10.5114/pjr.2021.107728. eng] 24. ozturk a, ozkan y, ozdemir rm, et al. radiographic changes in the lumbar spine in former professional football players: a comparative and matched controlled study. eur spine j 2008 jan;17(1):136-141. [doi: 10.1007/s00586-007-0535-3] 25. tsukagoshi y, kamegaya m, tatsumura m, et al. characteristics and diagnostic factors associated with fresh lumbar spondylolysis in elementary school-aged children. eur spine j 2020 oct;29(10):2465-2469. [doi: 10.1007/s00586-020-06553-x. eng] 26. sakai t, goto t, sugiura k, et al. bony healing of discontinuous laminar stress fractures due to contralateral pars defect or spina bifida occulta. spine surg relat res 2019 jan 25;3(1):67-70. [doi: 10.22603/ssrr.2018-0012. eng] 27. crawford ch, 3rd, ledonio cg, bess rs, et al. current evidence regarding the etiology, prevalence, natural history, and prognosis of pediatric lumbar spondylolysis: a report from the scoliosis research society evidence-based medicine committee. spine deform 2015 jan;3(1):12-29. [doi: 10.1016/j.jspd.2014.06.005.eng] 28. hardcastle ph. repair of spondylolysis in young fast bowlers. j bone joint surg br 1993;75(3):398-402. 29. choi jh, ochoa jk, lubinus a, et al. management of lumbar spondylolysis in the adolescent athlete: a review of over 200 cases. spine j 2022 oct;22(10):1628-1633. [doi: 10.1016/j.spinee.2022.04.011. eng] 30. hollabaugh wl, foley davelaar cm, mchorse kj, et al. clinical practice patterns of isthmic spondylolysis in young athletes: a survey of pediatric research in sports medicine members. curr sports med rep 2022;21(11):405-412. [doi: 10.1249/jsr.0000000000001008] 31. klein g, mehlman ct, mccarty m. nonoperative treatment of spondylolysis and grade i spondylolisthesis in children and young adults: a meta-analysis of observational studies. j pediatr orthop 2009 mar;29(2):146-156. [doi: 10.1097/bpo.0b013e3181977fc5. eng] 32. saw a, eales b, jones n, et al. lumbar bone stress injuries and nonunited defects in elite australian cricket players. clin j sport med 2023 [doi: 10.1097/jsm.0000000000001132] 33. kato k, otoshi k, kobayashi k, et al. clinical characteristics of early-stage lumbar spondylolysis detected by magnetic resonance imaging in male adolescent baseball players. j orthop sci 2022:s0949-2658(22)00302-00305. introduction performance can be improved in hard-training athletes by reducing the amount of training before competition, a procedure commonly known as tapering. 11 various studies on swimmers have determined that tapering can improve performance by 3%.8,11 similar improvement (3%) has also been shown in runners subsequent to a tapering regimen.6,9 many training variables can be altered during a tapering regimen. this includes frequency of training, duration, intensity and volume of training. scientific studies have shown that an optimal taper involves a reduction in training volume, but with intensity maintained as high as during hard training.11,14 similarly, the frequency of training sessions during a taper protocol is kept the same as during normal training. the recommended duration of a tapering protocol ranges from 7 to 14 days. this constitutes a standard taper protocol as used by most swimmers and runners world-wide.6,8 one concern of athletes commencing a tapering regimen is the possible negative effect of detraining as a result of the reduced training load during the taper. however, it has been established that detraining does not occur during the period of a properly constructed taper; rather, performance in competition is maximised.7,12 in a study on swimmers, it was shown that neural and cognitive capacities increase in efficiency as a result of a tapering protocol, and strength and muscle power increase markedly. as a result, propelling efficiency of swimming strokes is increased.13 optimal performance will occur when physiological capacity is maximised as the negative influences of fatigue due to a heavy training load are reduced, but before detraining occurs.10,16 to achieve this, the optimal duration of the taper should be approximately 2 4 weeks,5 and can be either a progressive reduction in training load or a step reduction. however, a progressive reduction may be more effective than a step reduction.1 anecdotal evidence has suggested that it may be possible to improve on the standard taper protocol, since it has been observed that some athletes do not always perform as well as expected immediately after such a taper as theory and studies suggest, but in fact run or swim faster times a week subsequent to the taper, when normal training has been resumed. thus it appears that there may be a delay before the full benefit of the taper is realised. a modified taper in which a standard taper is followed by a return to previous training load before competition may therefore be a superior tapering technique. this study aims to determine whether such a modified tapering protocol produces a better performance than a standard taper protocol in highly trained swimmers. methods subjects sixteen swimmers who were members of a local swimming club were selected to participate in the study. all were top provincial or national swimmers who were in current competitive hard training before the commencement of the study. original research article efficacy of a modified tapering protocol on swimming performance abstract objective. the aim of this study was to determine any difference in performance following two different tapering protocols after a period of heavy training. design. twelve swimmers who regularly trained at a high volume and intensity were recruited and trained together for 3 weeks. they were then randomly split into two groups (n=6 per group). one group underwent a standard taper protocol, while the second followed a modified taper in which training load was gradually resumed for 1 week following a standard taper. performance assessment following tapering consisted of 2 swims over a distance of 200 m, with a recovery period of 5 hours between swims. after resuming normal training, subjects tapered a second time, each group following the alternate protocol. outcome measures. total time and split times for each length, stroke rate, distance per stroke, and stroke index in a performance swim were determined as well as heart rate (hr), profile of mood state (poms), rating of perceived exertion (rpe) and muscle pain during each taper. results. mean swim times for the modified and conventional tapers were 134.7±9.1 and 134.7±9.3 seconds, respectively (mean ±sd). there was also no difference in the split times between groups, although both became slower in the final three laps. stroke rate, distance per stroke, and stroke index were also not different between protocols. there were no differences between protocols in hr, rpe or rating of muscle pain over the duration of the tapering period. however, there was a significant reduction in hr on day 5 of both tapers and a lower poms on days 3, 4 and 5 on the standard taper protocol. at the time of the performance swim, however, there was no difference in poms. conclusion. there were no performance or physiological advantages from the modified tapering protocol. correspondence: a n bosch mrc/uct research unit for exercise science and sports medicine boundary road 7700 newlands south africa tel: 27 21 650-4578 fax: 27 21 686-7530 e-mail: andrew.bosch@uct.ac.za a n bosch (phd) m medonca (bsc)(med)(hons)(exercise science) mrc/ uct research unit for exercise science and sports medicine, and department of human biology, university of cape town sajsm vol 20 no. 2 2008 49 pg49-58.indd 49 8/11/08 8:52:47 am all subjects were informed of the nature of the study and a consent form was signed before the commencement of the study, which was granted approval by the research ethics committee of the university of cape town. all swimmers were between 13 and 22 years of age and had been competing for at least 5 years. one subject was excluded from the study due to irregular attendance during the training protocol. three more were excluded due to injuries. therefore, 12 swimmers completed the study and these data are reported. total control of the training programme was granted to the researcher by the coach for the duration of the study. to improve compliance and motivation of the subjects, an incentive was used. this consisted of a prize given to the swimmer who attended the most sessions throughout the study and who recorded the fastest average time for all the performance swims. training protocol a two-group crossover experimental design was followed. the training protocol had four components consisting of hard training (continued from the normal hard training of the swimmers), taper, performance swim (gala) and return towards normal (hard) training. hard training all subjects in the study underwent a 3-week hard training lead-in phase in which the swimmers became accustomed to the attention given to them as a result of participating in the study, and meeting as a group for testing. the training programme followed was similar to the standard (hard) training programme used by each swimmer. group training was conducted at the same time in the evening, excluding saturdays and sundays. the pool temperature was 26.8° (± 0.9°). the supervised hard training protocol comprised 15 pool sessions. total distance swum (overall distance for 15 sessions) was 67 800 m with an average of 4 520 m (± 390 m) per training session in the pool. land training consisted of general body-strengthening exercises for the upper, middle and lower body. the land training took place on the pool deck. taper no land training took place during the taper phase. for this phase, the swimmers were randomly assigned into two groups. details of the protocols are shown in table i. the first group (n=6) underwent the modified tapering protocol which consisted of 7 days of training at 50% of normal training load, but with intensity maintained as high as that during the hard training phase. after the 7-day period, the swimmers returned progressively towards hard training for 4 sessions (monday thursday). specifically, there was a gradual increase in training volume during these 4 sessions, until the volume of the previous hard cycle was reached. the fifth day was a recovery session of reduced volume, before performance testing the following day. the second group (n=6) underwent the same standard taper protocol (50% of normal volume), but without the 4 days of return to normal training volume. the total distance swum during both tapers was identical. specifically, a total distance of 11 400 m was swum at an average of 2 280 m (± 116 m) per session. measurements during tapering heart rate testing heart rate (hr) was measured during both taper protocols. the hr measurement was done before training, on alternate days. swimming ‘pullers’ were used for these tests, which consisted of modified hand paddles as used in swimming training, connected to rubber bands. some of the swimmers in the study had used the pullers previously as a training tool. those swimmers who had not, familiarised themselves with the apparatus before testing commenced. the pullers were mounted above the swimmer so that the paddle rested at full arm extension above the swimmer’s head when standing. any discrepancy caused by the swimmer’s individual height was corrected by placing mats under the swimmer’s feet. the swimmers pulled from the extended position above the head, downward to the hips. the elbows remained in a partially flexed position and did not bend while performing the movement. the paddles were hinged to allow for rotation through the pulling movement. each puller had a set resistance determined by the length of the rubber band, with the load exerted measured using a hand scale, and varied from 12 to 14.5 kg. a polar heart rate monitor (vantage xl, usa) was used to measure hr and a seiko metronome (led and audio signal) was used to set the cadence for each swimmer. the metronome settings varied from 56 to 84 beats per minute. each swimmer kept their individual cadence at the specified rate, determined according to the specific strength of the swimmer and each used the same puller, cadence and mat setting for the entire study. the swimmers were instructed to pull for 3 minutes at their prescribed cadence while wearing the heart rate belt and transmitter. at the end of the 3 minutes, a 1-minute recovery was recorded during which the swimmers remained standing next to the pullers. hr data were recorded in 5-second intervals and downloaded onto a computer after each session. this included peak hr during the 3-minute workout, the 1minute recovery hr, and the rate of decline, calculated as the peak hr minus the 1-minute recovery hr. it must be noted that this series of tests are not specific to swim performance and any performance improvement in such tests may not translate to improved swimming performance. mood states a profile of mood state (poms) questionnaire was used to assess mood state.16 the poms questionnaire assesses total mood disturbance and 6 different mood states (tension, depression, anger, vigour, fatigue and confusion). the swimmers were asked to comtable i. overview of tapering protocols mon tue wed thu fri sat sun mon tue wed thu fri sat mod dist 2200 2400 2100 2400 2300 0 0 3600 4200 4600 5300 2900 gala (m) t t t t t t t r r r r rec std dist 4100 4200 4000 4100 4200 0 0 2200 2400 2100 2400 2300 gala (m) h h h h h t t t t t t t mod = modified taper; std = standard taper; t = taper at 50% volume; r = return to hard training load; rec = recovery session; h = normal hard training volume. 50 sajsm vol 20 no. 2 2008 pg49-58.indd 50 8/11/08 8:52:48 am plete the questionnaire every evening after each training session during the taper protocol. only 10 of the swimmers completed all the poms questionnaires correctly and these data are reported. the raw scores were converted to a standard score by subtracting the scale values of ‘tension’, ‘depression’, ‘anger’, ‘fatigue’ and ‘confusion’ from the scale value of ‘vigour’ and adding a constant of 100. an overall higher score indicates an improved mood state. muscular pain and rating of perceived exertion (rpe) a rating of pain score was obtained from each swimmer during the taper protocol in which the swimmers rated their degree of muscular pain against a numerical scale. the scale ranged from 0 (no pain at all) to 10 (maximal pain). this was done every evening prior to hr testing and training session. an rpe (borg scale) was also obtained from each swimmer. these data were collected daily. performance swim (gala) a gala to assess performance took place immediately after the taper and was split into two sessions. the first took place from 12h30 until 13h30. the second session took place from 17h00 until 18h00. this allowed the swimmers a full recovery between sessions, in which they were asked to perform one maximal 200 m swim of their best stroke. measures of performance the following data were recorded during the performance assessment: total time (seconds) for the swim (two seiko stop watches were used and the average of the two times was entered as the time for the swim), time (seconds) for each 25 m length of the pool (lap split), three timed strokes (as the swimmer crossed the midline of the pool, three strokes were timed using a seiko interval timer stopwatch and recorded as strokes/min), and the number of strokes taken per 25 m length (a volunteer counted the number of strokes taken). from these data the following was calculated: distance per stroke (meters/stroke; calculated by dividing the distance swum (25 m) by the number of strokes taken), swim velocity (meters/sec; calculated by dividing the total distance swum by the time) and stroke index (swimming velocity x distance per stroke). the stroke index is useful in evaluating a swimmer’s technique and efficiency. the higher the index, the more efficient the swimmer. at a given velocity, the swimmer that moves the greatest distance per stroke has the most effective technique.2 the performance measures for the two swims were then added together and an average score calculated. return to normal training following the performance test (gala) the swimmers returned to the hard training cycle during which the same training was followed as before. after a month on the hard training cycle, the groups started the alternate taper protocol to that followed previously, followed by another gala for performance assessment (the same hard training, land training, testing times and environment, testing methods and assistants were used during the entire study). a summary of the distances swum during the different phases of the study is shown in table ii. table ii. summary of the distances swum during the training protocols total distance average per swum training day hard training 67 800 m 4 520 m (while in study) final 7-day 11 400 m 2 280 m (50% taper period of hard training) overall 2-week 34 000 m 3 400 m taper* *this included the taper training and the return to hard training and the continued hard training components, depending on taper protocol followed. table iii. anthropometrical data of the subjects subject height (cm) age (years) weight (kg) body fat (%) group a 1 192.3 22 88.2 21.2 2 181.2 17 71.4 18.1 3 172.5 17 68.3 18.5 4 172.5 16 65.5 17.5 5 161.4 13 51.4 22.2 6 15 9.3 14 49.3 21.3 mean 172.3 16 65.7 19.8 sd 11.2 2 13.0 1.8 group b 1 178.3 16 72.3 16.5 2 174.4 16 68.4 25.7 3 199.2 16 82.3 14.9 4 148.7 13 47.6 28.1 5 166.6 15 54.7 13.2 6 188.4 16 68.5 14.5 mean 175.9 15 65.6 18.8 sd 15.9 1 11.4 5.8 sajsm vol 20 no. 2 2008 51 pg49-58.indd 51 8/11/08 8:52:48 am statistics all data were expressed as mean ± sd. an analysis of variance with repeated measures was used to assess difference between protocols (stroke rate, distance per stroke, swim velocity, stroke index, 1-minute recovery heart rate, peak heart rate, and rate of decline). where significant differences were found, a scheffe’s post-hoc test was used. a paired t-test for dependant samples was used to analyse the data obtained for performance time at the end of each taper. the friedman analysis of variance test for non-parametric data was used to analyse the subjective ratings of each taper (muscle pain, poms and rpe). the mann-whitney test was used to determine whether differences occurred between specific time points. statistical significance was accepted when p<0.05. results anthropometry basic anthropometrical data for all the subjects are presented in table iii. measurements of weight and height were taken at the commencement of the training protocol using a seca model 708 scale. body fat measurements were taken using the four-site method described by durnin and womersley.4 heart rate peak heart rate there was no significant difference (p>0.05) in the peak hr between the two tapers. however, peak hr on day 9 of each taper was significantly lower than on days 1 and 3. 1-minute recovery heart rate and rate of decline there were no significant differences between protocols in either the 1-minute recovery hr or the rate of decline. profile of mood state the poms score was found to be significantly (p<0.05) reduced on the standard protocol on days 3, 4, and 5 of the taper (fig. 1). rating of perceived exertion significant differences were found in rpe between the modified and standard protocols on days 3, 5 and 9 of the tapers (fig. 2). however, there was no significant difference at the end of the tapers when the performance swim was undertaken. there was a significant change over the duration of the tapers. muscular pain rating there were no significant differences between taper protocols or over the duration of the taper protocol. distance per stroke and stroke index there were no significant differences between the protocols in either distance per stroke or stroke index, but both were significantly less on the final three laps of the performance swims than at the start (p<0.05) (fig. 3). stroke rate there were no significant differences either between protocols or on the different laps of the performance swim. swim velocity there were no significant differences in the swim velocity on each lap between the taper protocols. however, there was a decline in swimming velocity regardless of the taper employed (fig. 4). race time as would be expected from fig. 4, race times were not significantly different between protocols. swim times for individual subjects are shown in table iii. discussion the objective of this study was to examine swimming performance after following a standard and a modified standard tapering protocol. the most important finding was that there were no differences in the swim times recorded following the standard and modified tapering protocols. of the 12 subjects, 8 recorded faster times after the standard taper (subjects 1, 2, 4, 5, 6, 7, 9, 10). after the completion of the study, each swimmer was asked which taper they favoured. ten of the 12 swimmers favoured the standard taper (hard training followed by a standard taper before the performance swim), while only two swimmers favoured the modified taper (standard taper followed by a return to hard training before a performance swim). interestingly, both these were distance swimmers and both recorded faster times on the modified taper. however, the two other swimmers who recorded faster times on the modified taper favoured the standard taper, despite their poorer performance after that taper protocol. since there were no significant differences in hr between the two taper protocols, it appears that there were no differences in the degree to which physiological stress was reduced on either protocol. however, since peak hrs were significantly reduced on day 9 of both the tapers, there appears to have been a general improvement in physiological stress response. curiously, this was not continued through to day 11. there appears to be no logical explanation for this, other than anxiety due to the forthcoming gala the following day. although hr response was similar regardless of the taper protocol, rpe was lower on the standard protocol on days 3 and 5, higher on day 9, and the same on both protocols at the time of the performance swim (fig. 2). thus there was no apparent relationship between rpe changes and hr response, as rpe was lower on the modified taper (days 3 and 5), without a corresponding difference in hr. in the case of poms, the scores were higher on the modified taper at the time rpe was lowest (days 3 and 5). it is difficult to ascribe any physiological significance to these responses.  fig. 1. profile of mood states for the final 11 days of the different taper protocols (n=12). values are expressed as mean ± sd. *p<0.03. taper-hard = modified taper protocol; hard-taper = standard taper protocol. 52 sajsm vol 20 no. 2 2008 pg49-58.indd 52 8/11/08 8:52:49 am although the tapering protocols did not result in any difference in swim performance, there were changes as the swim progressed in parameters related to performance, regardless of tapering protocol employed. specifically, as with previous studies,15 performance measures declined as the race progressed, i.e. distance per stroke, stroke index, and swim velocity. it has been suggested that the reduced distance per stroke later in the swim is the result of increased drag as the swimmer becomes tired.3 the change in stroke index also indicates increased fatigue. although these changes all indicate fatigue later in the swim, neither protocol was superior in reducing these negative effects. nevertheless, swim velocity was significantly slower in the latter stages of the swim as a result. in conclusion, there were no significant differences in performance due to the different taper protocols employed. the traditional taper, however, was favoured by the swimmers compared with the modified protocol. there is therefore no reason to suggest a change in tapering procedure and the anecdotal observations on which the study was based, i.e. that performance may be optimal some days after a tapering protocol has been completed and normal training resumed, were not borne out by scientific investigation in this particular cohort of swimmers. however, future studies should repeat the study in which swimmers who participate in shorter or longer distance events are studied, in swimmers who use higher training volumes, and swimmers who are more uniform in age. another type of taper for use when two competitions are in close proximity to each other should also be investigated. finally, testing of the modified protocol in runners, in which there is a large eccentric component, should be considered. references 1. banister ew, carter jb, zarkadas pc. training theory and taper: validation in triathlon athletes. eur j appl physiol occup physiol 1999; 79: 182-91. 2. costill dl, kovaleski j, porter d, kirwan j, fielding r, king d. energy expenditure during front crawl swimming: predicting success in middledistance events. int j sports med 1985; 6: 266-70. 3. craig ab, jr., skehan pl, pawelczyk ja, boomer wl. velocity, stroke rate, and distance per stroke during elite swimming competition. med sci sports exerc 1985; 17: 625-34. 4. durnin jv, womersley j. body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. br j nutr 1974; 32: 77-97. 5. fitz-clarke jr, morton rh, banister ew. optimizing athletic performance by influence curves. j appl physiol 1991; 71: 1151-8. 6. houmard ja. impact of reduced training on performance in endurance athletes. sports med 1991; 12: 380-93. 7. houmard ja, costill dl, mitchell jb, park sh, hickner rc, roemmich jn. reduced training maintains performance in distance runners. int j sports med 1990; 11: 46-52. 8. houmard ja, johns ra. effects of taper on swim performance. practical implications. sports med 1994; 17: 224-32. 9. houmard ja, scott bk, justice cl, chenier tc. the effects of taper on performance in distance runners. med sci sports exerc 1994; 26: 62431. 10. mujika i. the influence of training characteristics and tapering on the adaptation in highly trained individuals: a review. int j sports med 1998; 19: 439-46. 11. mujika i, padilla s, pyne d, busso t. physiological changes associated with the pre-event taper in athletes. sports med 2004; 34: 891-927. 12. neufer pd. the effect of detraining and reduced training on the physiological adaptations to aerobic exercise training. sports med 1989; 8: 302-20. fig. 2. rpe values for the final 11 days for the different taper protocols. *p<0.000001 over the duration of the tapering period. +p<0.01: taper 1 (taper-hard) different to taper 2 (hard-taper) on day 3. ++p<0.0004: taper 1 (taper-hard) different to taper 2 (hardtaper) on day 5. +++p<0.0005: taper 1 (taper-hard) different to taper 2 (hard-taper) on day 9. values are expressed as mean ± sd. taper-hard = modified taper protocol; hard-taper = standard taper protocol.  fig. 3. stroke index for the different tapers (n=12). values are expressed as mean ± sd. *p<0.005: lap 6 different to lap 2. **p<0.04: lap 7 different to lap 3. ***p<0.00004: lap 8 different to lap 2. lap 1 was not compared for significance as it included the dive. there were no differences between protocols. taperhard = modified taper protocol; hard-taper = standard taper protocol. fig. 4. the swim velocity (m.s-1) for the two taper protocols (n=12). values are expressed as mean ± sd. *p<0.0001: lap 4 different to lap 2. ** p<0.003: lap 6 different to lap 3. ***p<0.0000001: lap 8 different to lap 2. lap 1 was not compared for significance as it included the dive. taper-hard = modified taper protocol; hard-taper = standard taper protocol. sajsm vol 20 no. 2 2008 53 pg49-58.indd 53 8/11/08 8:52:50 am 13. rushall bs, shewchuk ml. effects of thought content instructions on swimming performance. j sports med phys fitness 1989; 29: 326-34. 14. shepley b, macdougall jd, cipriano n, sutton jr, tarnopolsky ma, coates g. physiological effects of tapering in highly trained athletes. j appl physiol 1992; 72: 706-11. 15. wakayoshi k, yoshida t, ikuta y, mutoh y, miyashita m. adaptations to six months of aerobic swim training. changes in velocity, stroke rate, stroke length and blood lactate. int j sports med 1993; 14: 368-72. 16. wittig af, houmard ja, costill dl. psychological effects during reduced training in distance runners. int j sports med 1989; 10: 97-100. introduction the comrades marathon is a 90 km ultramarathon race, run annually between durban and pietermaritzburg, south africa. however, the start and finish of the race alternate each year, and the race is therefore run in different directions. in the ‘up’ run the race starts at sea level in durban, and runners ascend to the finish in pietermaritzburg, at 650 m above sea level. the highest point in the race is 870 m above sea level. in the ‘down’ run, the race starts in pietermaritzburg, and runners descend to the finish in durban.11 marathon and ultramarathon races impose severe physiological stresses on runners.6,17 previous studies on runners of the 90 km comrades marathon have provided information regarding changes in ecg activity,13 serum enzyme activities, fluid balance,12 renal function,19 factors explaining the development of hyponatraemic encephalopathy,18 and the decrement in muscle power associated with muscle damage.6 it is well documented that muscle damage is a common occurrence associated with distance running.6,17 exercise-induced muscle damage is characterised by a disruption of the sarcolemma,2 sarcotubular system,2,4 contractile components of the myofibril, the extracellular matrix and the cytoskeleton.15 distance running is original research article differences in muscle pain and plasma creatine kinase activity after ‘up’ and ‘down’ comrades marathons abstract objective. the aim of this study was to compare the acute changes in muscle pain and plasma creatine kinase (ck) activity following the ‘up’ and ‘down’ comrades marathon. design. this was a quasi-experimental design. eleven male runners (39.7±9.3 years) completed the ‘up’ comrades marathon, and 11 male runners (41.0±8.4 years) completed the ‘down’ comrades marathon the following year. maximum oxygen consumption and peak treadmill running speed were measured 2 weeks before the race. daily measurements of muscle pain and plasma creatine kinase (ck) activity were recorded 1 day before, and for 7 days after the race. results. muscle pain remained significantly elevated for up to 7 days after the comrades marathon, compared with pre-race values (p<0.0009). the pain scores following the ‘down’ run were significantly higher than the pain scores following the ‘up’ run for at least 7 days after the race (p<0.004). plasma ck activity recorrespondence: theresa burgess division of physiotherapy school of health and rehabilitation sciences f45 old main building groote schuur hospital anzio road 7725 observatory south africa tel: 27 21 406-6171 fax: 021 406-6323 e-mail: theresa.burgess@uct.ac.za theresa l burgess1, 2 (bsc (physio), bsc (med)(hons) (exercise science)) michael i lambert1 (phd) 1 mrc/uct research unit for exercise science and sports medicine, department of human biology, university of cape town, sports science institute of south africa 2 division of physiotherapy, school of health and rehabilitation sciences, university of cape town mained significantly elevated for up to 5 days after the comrades marathon, compared with pre-race values (p<0.007). plasma ck activity following the ‘down’ run was significantly higher than the plasma ck activity following the ‘up’ run for 5 days after the race (p<0.04). a high degree of intra-individual variability in plasma ck activity was observed. conclusions. the ‘down’ comrades marathon causes significantly more muscle pain and plasma ck activity compared with the ‘up’ comrades marathon. further studies are required to accurately define the regeneration of muscle following the comrades marathon. 54 sajsm vol 20 no. 2 2008 pg49-58.indd 54 8/11/08 8:52:51 am jsm0404pg000ed. introduction a high incidence of upper respiratory tract infections (urtis) has been reported in athletes.7,19,21,22 these infections occur during periods of intense training and after major competitions such as ultramarathon events.28 to compete successfully in these ultramarathon events athletes need to train at least daily, and often twice per day, and therefore it is possible that chronic suppression of immune function may result from the cumulative acute post-exercise suppression of each successive exercise bout.14 the increase in infection risk after participation in intense exercise provides a model to study the efficacy of agents that may enhance resistance to such infections.19,22 a number of studies have investigated the impact of nutritional supplements on immune status and urtis, with conflicting results being reported.1,18,22 however, none have investigated the role of an l-methionine combination supplement (l-methionine, vitamin b6, vitamin b12, folic acid and 10 sports medicine vol 16 no.1 2004 original research article the effects of an l-methionine combination supplement on symptoms of upper respiratory tract infections and performance in ultramarathon runners before, during and after ultra-endurance exercise l m harden (ba hons (biokinetics), msc)1 n neveling (ba hons (biokinetics))2 f rossouw (ba hons (biokinetics), ma (human movement studies))2 s j semple (m tech (sport and exercise technology))2 f e marx (b tech (sport and exercise technology))2 j rossouw (dsc (biochemistry))2 g rogers (phd)1 1school of physiology, university of the witwatersrand, johannesburg 2department of sport and rehabilitation sciences, tshwane university of technology, pretoria abstract objective. to evaluate whether supplementation with an l-methionine combination would reduce the incidence of upper respiratory tract symptoms (urts) and improve performance in ultramarathon runners. design. a double-blind placebo-controlled study. setting. twenty-one ultramarathon runners (17 males, 4 females) preparing for participation in an 87.3 km ultramarathon. interventions. l-methionine combination supplement (lmethionine, vitamin b6, vitamin b12, folic acid and magnesium) or placebo containing potato starch. main outcome measures. incidence of urts was recorded during the runner's preparation for an ultramarathon race (75 days) and recovery from the same (75 days). cd4+, cd8+ cell counts and ratios were measured pre race, immediately post race and 75 days post race. vo2max and endurance fitness (percentage vo2max at 4 mmol-1 lactate concentration) were measured during the preparation period for the race. results. during the preparation period the incidence of urts was 36% in the supplement group and 80% in the placebo group (p = 0.08). the incidence of urts during the 3 weeks post race was 27% in the supplement group and 40% in the placebo group (p = 0.65). the cd4+/cd8+ cell ratios were not significantly different between groups. endurance fitness prior to the race and race times were not significantly different. conclusions. although the findings of the current study show that an l-methionine combination supplement did not reduce the incidence of urts or improve performance in ultramarathon runners, benefits may be found with a more detailed investigation using larger sample sizes and immunosuppressed athletes. correspondence: l harden school of physiology university of the witwatersrand medical school 7 york rd parktown 2193 tel: 011-717 2462 fax: 011-643 2765 e-mail: hardenlm@physiology.wits.ac.za magnesium) on symptoms of urtis in athletes. results from a study investigating the effects of an l-methionine combination supplement in hiv+ patients propose that it slows the rate of decline in cd4+ cell counts and improves the viral load levels after 3 months.32 the 5 active substances (l-methionine, vitamin b6, vitamin b12, folic acid and magnesium) in the supplement participate in the maintenance of glutathione status and have been shown to elevate intracellular glutathione.16,31,33 magnesium is an essential co-factor for the enzyme methionine adenosyl transferase, which forms s-adenosylmethionine (sam) from l-methionine.16 sam can provide a methyl group to a variety of substances and s-adenosylhomocysteine (sah) is formed as a product.16 sah can then form l-homocysteine and adenosine.16 folate and vitamin b12 are essential co-factors for the remethylation of l-homocysteine to l-methionine. sah can be converted by 3 enzymatic steps (which involve vitamin b6) to l-cysteine and subsequently to glutathione.16 it is glutathione (a major endogenous antioxidant) that has been found to have antiviral activity and to be important as a mediator of normal immune responsiveness.9,11 strenuous exercise has been shown to deplete tissue glutathione content12,13 and increase the risk of urtis.19 in addition to studying the effects of antioxidant supplements on immune status and urtis, a number of studies have also investigated their role in performance.23,25,30,34 although several studies have indicated that supplementation with vitamins e and c decreases exercise-induced oxidative stress, there is little evidence that antioxidant supplementation can improve human performance.24 however, one well-designed study has reported an improvement in muscular endurance following supplementation with nacetylcysteine (a glutathione precursor).25 therefore, the purpose of this study was to use a doubleblinded, placebo-controlled design to determine firstly whether supplementation with an l-methionine combination supplement would decrease the incidence of symptoms of urtis in runners during their preparation and recovery from an ultramarathon race, and secondly whether this supplement would impact on their endurance fitness prior to the ultramarathon and ultimately how it would influence their performance in the ultramarathon. methods subjects prior to commencement of this study, ethics approval was obtained from the committee for research on human subjects of the university of the witwatersrand. thirty healthy well-trained, ultramarathon runners (20 males and 10 females) preparing for participation in an 87.3 km ultramarathon race volunteered to participate in this study after providing informed consent. runners reported having run on average 5 ± 3 (mean ± sd) ultramarathons, with the best marathon performances averaging 3.17 ± 0.22 (mean ± sd) hours. subjects were paired according to vo2max levels, proposed training programmes and gender. each member of a pair was randomly assigned to either the supplementation (experimental) or placebo group. during the training period prior to the race 5 subjects withdrew from the study due to orthopaedic injuries while 4 subjects failed to comply with testing procedures and were asked to discontinue with the study. the dropout rate in the current study (n = 9) was high but comparable with that reported in other studies (n = 8).22,23 the sample was finally fixed at 21 subjects, which included 4 females and 17 males (n = 11 supplement and n = 10 placebo). of the final 21 subjects, 6 subjects in each group remained paired according to the criteria stated above. performance measurements the subjects were required to report to the testing laboratory situated at an altitude of 1 330 m with an average barometric pressure of 656 mmhg and a room temperature regulated at 20 22ºc on day 1 (75 days before the race). all subjects were tested within the same week. the subjects were familiarised with the testing equipment and procedures prior to the commencement of testing. subjects were asked not to train for 12 hours prior to all the testing, not to train hard (≤ 70% of maximal heart rate) on the day before testing and not to consume any food or caffeinated drinks 3 hours prior to testing. each subject was asked to run on a motorised treadmill (quinton q65 series 90, quinton instrument co., bothell, wa, usa). maximal aerobic capacity (vo2max) was measured using a continuous model adapted from the astrand protocol.15 the criteria for vo2max included subjects obtaining 2 of the following 3 criteria: a plateau in vo2 despite an increase in workload, a respiratory exchange ratio in excess of 1.10, and blood lactic acid levels > 8 mmol.-1.6 oxygen consumption and ventilation were determined using the medgraphics cardio2 combined vo2/ecg exercise system (medical graphics corporation, st. paul, mn, usa). the lactate concentration for capillary blood was measured using the accusport analyzer (boehringer mannheim, bmbh, mannheim, germany) and the bm-lactate test strips. blood samples were collected during the last 30 s of each workload during the vo2max test. capillary blood was obtained by pricking a fingertip with a lancet. on average 5 blood samples were obtained during each vo2max test. lactate concentrations at each workload were plotted and an exponential curve was fitted using table curve 2d (jandel scientific software, san rafael, ca, usa). the percentage vo2max at 4 mmol. -1 lactate was calculated and used as a measure of endurance fitness.8,10 the above tests were repeated again 14 days before the race. all tests were again performed within 1 week and at the same time of the day as the first testing session. in addition to endurance fitness, race time (as obtained from official race records) was also used as a measure of performance. supplementation supplementation started on day 2 and ended on day 150 of the study. the supplement (bio boost) and placebo were supplied by biomox pharmaceuticals in capsule form and administered orally. the active ingredients administered in sports medicine vol 16 no.1 2004 11 the supplement were: l-methionine 405 mg, folic acid 0.36 mg, vitamin b6 1.575 mg, vitamin b12 0.01125 mg, magnesium 135 mg. the placebo contained potato starch (500 mg per day) and no active ingredients. from day 1 to day 7 (first week of the study) and day 76 to day 83 (first week after the race), subjects ingested 3 capsules twice a day (1 215 mg of l-methionine, 1.08 mg folic acid, 4.725 mg vitamin b6, 0.03375 mg vitamin b12 and 405 mg magnesium) on an empty stomach. after these 2 periods (i.e. days 8 75 and days 84 151) subjects were instructed to ingest 2 capsules twice a day (810 mg l-methionine, 0.72 mg folic acid, 3.15 mg vitamin b6, 0.0225 mg vitamin b12 and 270 mg magnesium) on an empty stomach. this schedule of ingestion was prescribed by the supplier and manufacturer of the product based on trials done on individual patients by the original formulators (unpublished data) and was the same for the 2 groups. incidence of upper respiratory tract symptoms (urts) the incidence of symptoms of urtis was recorded daily by the subjects in a logbook provided which was based on the questionnaire used in the studies investigating the effect of glutamine or placebo ingestion on the incidence of infections in runners.2 the adapted questionnaire was not validated prior to use in this study. subjects were asked to record all symptoms reported under the headings of cold, cough, sore throat, running nose, sneezing and influenza and for how long the symptoms were present.2 a subject was considered to have an illness when he or she reported 3 symptoms for a cold (cough, sore throat, running nose, sneezing) or influenza (fever, aches and pains in joints or muscles, cough, sore throat) such that they did not train or such that they consulted a doctor for treatment. other illnesses, e.g. diarrhoea and vomiting were not included. the incidence of the symptoms and the duration of the symptoms (number of days the symptoms were present) was calculated. recordings were controlled monthly with each visit to the laboratory to collect more supplements and telephonically when booking each appointment. the diagnosis was not verified by clinical examination although patients did indicate if they had seen a medical doctor for treatment. blood sampling cd4+ and cd8+ measurements were taken on day 75 (18 hours pre-race), day 76 (10 min post race) and on day 150. with each sampling session blood was drawn from a forearm vein into evacuated collection tubes. the blood for the cd4+ and cd8+ measurements was collected in a 4.5 ml vacuette (k3e edta k3, greiner labortechnik). following processing, specimens were packed in a refrigerated container and transported to a central laboratory where they were analysed within 18 hours of collection. the proportions of t-cells (cd4+ and cd8+) were measured using flow cytometry (facscount, becton dickinson, san jose, usa) which includes the use of fluorescent labelled monoclonal antibodies to cell surface antigens as previously described.26 all concentrations were corrected for changes in plasma volume post race.3 training all training information (running distance, time and intensity) and injuries were recorded weekly in a standardised training logbook given to the subjects. the training logbooks were adapted from those used in a study investigating the effects of lactate-correlated training on running performance but were not validated prior to use in this study.27 nutrition the subject's compliance with capsule use was recorded daily in a logbook given to the subjects. in addition, every 4 weeks subjects were asked to indicate how many capsules were left before they received a new bottle of capsules. subjects were asked not to take any other vitamin and mineral supplements for the duration of the study. dietary habits were evaluated from a 24-h dietary recall. as a method of reporting food intake the 24-h dietary recall questionnaire has been validated against weighted 7-day food records.4 the dietary recall was completed daily by each subject to ensure that subjects did not change their diets over the duration of the study. subjects were taught how to keep accurate food records prior to commencement of the study. nutrient content of each athlete's reported daily dietary intake was assessed (macro and micro nutrients) using a computerised dietary analysis system (food fundi analyzer 2, professional penta medical systems, johannesburg, south africa). statistical analysis data are expressed as means ± standard deviation (sd). the analysis of changes in all blood measurements (cd4+, cd8+ cell counts and ratio) was done using an analysis of variance (anova) procedure for repeated measures to estimate main effects (group or time) and an interaction effect (group x time) followed by a tukey-kramer multiple comparisons post-hoc test. for all other dependent variables the unpaired t-test was used to test for the significance of the differences between the groups. a fisher's exact probability test was used to analyse a 2 x 2 contingency table for being sick and not being sick (incidence of illness). the level of significance used was p ≤ 0.05. a post hoc power analysis showed the power for the following statistical tests: repeated measures anova (time effect power = 0.990, time x group effect power = 0.153); unpaired t-tests (%vo2max @ 4mmol. -1 lactate power = 0.7968, duration of symptoms power = 0.4264) and fisher's exact test (incidence of illness power = 0.3196). results physical characteristics the physical and performance characteristics of the subjects are given in table i. there was no significant group differences on any of the parameters measured. it should be noted that based on the race finishing times and vo2max values the runners would be classified as non-elite, experienced and well-trained runners.20 12 sports medicine vol 16 no.1 2004 incidence of upper respiratory tract symptoms (urts) the incidence of symptoms of urtis in both groups during the 75 days of preparation is shown in table ii. during the preparation period the percentage of symptoms of urtis (p = 0.08) and the duration of symptoms per illness incident (p = 0.13) was not significantly different. the incidence of urts (p = 0.65) and duration of symptoms (p = 0.55) during the 3 weeks following the race was not significantly different. during the entire 75 days of recovery from the race the incidence of urts (p = 1.00) and duration of symptoms was also not significantly different (p = 0.66). training programmes there was no significant difference in the total training distance completed in preparation for the race, with the supplement group completing 896 ± 235 km and the placebo group 892 ± 192 km. physiological responses aerobic capacity variables monitored during preparation for the race are shown in table iii. the supplement group had a significantly greater percentage vo2max at 4 mmol. -1 lactate concentration (endurance fitness) than the placebo group 12 14 days prior to the start of the race. however the mean change in endurance fitness over the 75-day training period was not significantly different. no significant differences in race times were found, with the supplement group running 8.45 ± 1.54 hours and the placebo group 8.51 ± 1.08 hours. prior to the start of the race (18 hours) no significant differences were noted in the immune cell subsets (figs 1 and 2). cd4+ cells decreased significantly in both groups immediately post race (fig. 1) while the cd8+ cells only decreased significantly in the supplement group immediately post race (fig. 2). the cd4+/cd8+ ratio did not change significantly immediately post race in both groups or 75 days post race (fig. 3). no significant differences were noted between the groups for the cd4+, cd8+ cell counts and ratios. nutrition the subjects were all caucasian, from the same socio-economic background and no significant differences (p > 0.05) between groups were observed for nutrient analysis of food records across all time periods. the average daily energy intake for all was 13 600 ± 4 009 kj.day-1, with carbohydrate, fat and protein respectively comprising 58 ± 11.5%, 24.2 ± 6.3% and 15.4 ± 3.5% of the daily caloric intake. discussion the essential finding of this study was that 150 days of supplementation with an l-methionine combination had no significant effect on the incidence of urts and race sports medicine vol 16 no.1 2004 13 table i. physical and performance characteristics of the subjects* supplement placebo group group (n = 11) (n = 10) p-value age (years) 36 ± 3 35 ± 8 0.74 height (m) 1.73 ± 0.09 1.75 ± 0.05 0.67 mass (kg) 69.5 ± 10.7 68.9 ± 8.4 0.89 vo2max (ml.kg-1.min-1) 58 ± 8 57 ± 7 0.78 best standard marathon time (hours) 3.18 ± 0.25 3.16 ± 0.20 0.84 best comrades marathon (90 km) time (hours) 8.37 ± 1.09 8.27 ± 1.07 0.83 *values are means ± sd. table iii. aerobic capacity variables monitored during preparation for the race june parameters april (12-14 days prior to the race) vo2max (ml.kg -1.min-1) supplement 58 ± 8 59 ± 7 placebo 57 ± 7 58 ± 7 percentage vo2max at 4 mmol.-1 lactate concentration supplement 86 ± 4 87 ± 4* placebo 84 ± 5 83 ± 5 values are means ±sd; n = 11 supplement and n = 10 placebo subjects. difference between absolute values: april p > 0.05;*june p < 0.05 difference between delta values (june april); p = 0.08 for percentage vo2max at 4 mmol.-1 lactate concentration; vo2max p = 0.84. table ii. percentage of symptoms of urtis and duration of symptoms during the study subjects with % symptoms p-value mean duration of p-value subject/ group symptoms/total group of urtis % symptoms symptoms (days) mean duration of symptoms preparation supplement 4/11 36 3 ± 1 (0 75 day) placebo 8/10 80 0.08 5 ± 3 0.13 3 weeks supplement 3/11 27 4 ± 2 post-race 0.65 0.55 (76 97 day) placebo 4/10 40 6 ± 4 during supplement 6/11 55 6 ± 4 recovery 1.00 0.66 (76 -150 day) placebo 6/10 60 5 ± 3 performance in ultra-endurance runners. there is evidence for the role of nutrient supplements in modulating the incidence of urtis post race. peters et al.22 examined the effect of supplementation with vitamin c (an antioxidant) on the urtis of ultramarathon runners competing in the same race in 1990 and showed that 21 days of vitamin c supplementation reduced the post-race incidence of urtis. glutamine (an amino acid) supplementation immediately post race and 2 hours post race has also been shown to reduce the incidence of infections within 7 days post race in runners competing in marathon and ultramarathon events.2 the results of the current study show that supplementation with an l-methionine combination did not influence the incidence of urts during the training for or recovery from an ultramarathon race in runners nor did it reduce the duration of symptoms. one main difference between the above two studies and this study is the use of larger sample sizes (27 88 subjects). owing to the long duration of the study 9 subjects withdrew, which is similar to what has been reported in other studies.22,23 the small sample size used in the current study could influence the acceptance or rejection of the null hypothesis. in addition to the results on urts, we did not find any significant differences in the cd4+ and cd8+ cell counts or cd4+/cd8+ cell ratios post race. this immune marker was used as an l-methionine combination supplement (supplement with the same combination as used in this study but at a higher concentration) and n-acetylcysteine (nac) treatment, both of which are glutathione precursors and have been shown to slow the decrease of cd4+ cell counts in hiv+ patients.12,32 the stress of prolonged exhaustive exercise has been shown to lower the cd4+ cell counts and cd4+ to cd8+ cell ratio in athletes.1 this marker has also been used in other studies which have examined the effect of supplementation on the immune system post marathon and it has been suggested that a ratio of cd4+/cd8+ cells below 1.5 is below normal and may be a cause of and an indicator of immunosuppression in athletes.17,29 there are, however, several factors which might account for the negative findings regarding the immune responses measured in this study. firstly no cd4+/cd8+ cell measurements were taken during the training period in which the largest difference in the incidence of urts was noted between the supplement and placebo groups. secondly, enumeration of circulating cells does not provide as conclusive information on immune function or activation of cells as does examining direct measurements of cell function.35 thirdly, the reported symptoms of urtis by the subjects were not verified by clinical examination which would have confirmed the presence of an infection. fourthly, including a non-exercising control group would have strengthened the findings of the current study as the incidence of symptoms in the general population could have been compared with that 14 sports medicine vol 16 no.1 2004 fig. 1. cd4+ cell measurements in both groups pre-race, immediately post-race and 12.5 weeks post-race (** p < 0.001 for the supplement group and * p < 0.001 for the placebo group immediately post-race when compared with pre-race values). (values are means ± sd; n = 11 supplement and n = 10 placebo subjects). fig 2. cd8+ cell measurements in both groups pre-race, immediately post-race and 12.5 weeks post-race (* p < 0.01 for the supplement group immediately post-race when compared with pre-race values). (values are means ± sd; n = 11 supplement and n = 10 placebo subjects). fig 3. cd4+/cd8+ ratio measurements in both groups prerace, immediately post-race and 12.5 weeks post-race. (values are means ± sd; n = 11 supplement and n = 10 placebo subjects). found in the exercising group. furthermore it has been suggested that the cd4+ t-cell system may be negatively affected not only by suboptimal but also by supraoptimal glutathione levels.12 therefore further investigation is needed to not only analyse the activity of the immune cells in response to l-methionine combination supplementation but also in relation to glutathione levels. in addition to the role of antioxidant supplements in immune function, previous studies have also examined their effects on performance due to growing evidence indicating that radicals and other reactive oxygen species may contribute to muscular fatigue.24 conflicting results have been presented from these studies which may be due to agent administration, dosage and the pattern of muscular activity used to induce fatigue. weight et al.34 found that 3 months of vitamin and mineral supplementation had no effect on oxygen consumption, blood lactate turnpoint, peak treadmill running speed and 15 km time trial performance in 30 well-trained runners. time to exhaustion at 70% vo2max was not reduced in 11 highly trained male triathlon athletes after 4 weeks of supplementation with vitamin e, coenzyme q10, cytochrome c and inosine.30 reid et al.,25 however found an improvement in muscular endurance (during low frequency stimulation) following treatment with 150 mg n-acetylcysteine (a glutathione precursor). n-acetylcysteine has been shown to increase glutathione levels in plasma and bronchoalveolar lavage fluid in humans; however its use is limited due to a number of side-effects.25 in the present study no change in vo2max and endurance fitness (percentage vo2max at 4 mmol. -1 lactate) was found after 75 days of supplementation. the finding that performance in the race (87.3 km) was unaltered by supplementation tends to confirm the laboratory findings. these findings are therefore in keeping with the majority of studies showing that long-term supplementation with antioxidant nutrients does not improve human performance.5,24,34 conclusions in summary, although the findings of the current study do not support the use of an l-methionine combination supplement in reducing the incidence of urts in ultramarathon runners, the positive results found with hiv+ patients does suggest that this supplement has a role to play in immune function. future studies will need to be conducted with larger sample sizes, will need to include measures of immune function and glutathione levels, and will need to be directed at athletes who are shown to be immunosuppressed such as overtrained athletes or patients who present with specific disease states in which glutathione or its precursors are depleted. acknowledgements we are grateful to the runners who participated in this study, merc pharmaceuticals, biomox pharmaceuticals and the faculty of health science medical research endowment fund of the university of the witwatersrand for financial support. we would like to thank ungerer laboratories for their technical assistance, izak smit for all his help with the statistical analysis and professor lucille smith for critical advice and careful reading of the manuscript. references 1. castell l, newsholme e. the effects of oral glutamine supplementation on athletes after prolonged, exhaustive exercise. nutrition 1997; 13: 738-42. 2. castell l, poortmans, j, newsholme, e. does glutamine have a role in reducing infections in athletes? eur j appl physiol 1996; 73: 488-90. 3. dill d, costill, d. calculation of percentage changes of blood, plasma and red cells in dehydration. j appl physiol 1974; 37: 247-8. 4. edington j, thorogood m, geekie m, ball m, mann j. assessment of dietary intake using dietary records with estimated weights. j hum nutr diet 1989; 2: 407-14. 5. goldfarb ah. antioxidants: role of supplementation to prevent exerciseinduced oxidative stress. med sci sports exerc 1993; 25: 232-6. 6. gore c. physiological tests for elite athletes. australian sports commission. champaign, illinois: human kinetics, 2000: 122-3. 7. heath g, ford e, craven t, macera c, jackson k, pate r. exercise and the incidence of upper respiratory tract infections. med sci sports exerc 1991; 23: 152-7. 8. heck h, mader a, hess g, mücke r, müller r, hollmann w. justification of the 4-mmol/l lactate threshold. int j sports med 1985; 6: 117-30. 9. ho wz, douglas sd. glutathione and n-acetylcysteine suppression of human immunodeficiency virus replication in human monocyte/ macrophages in vitro. aids res hum retroviruses 1992; 8: 1249-53. 10. jacobs i. blood lactate: implications for training and sports performance. sports med 1986; 14: 103-8. 11. kalebic t, kinter a, poli g, anderson me, meister a, fauci as. suppression of human immunodeficiency virus expression in chronically infected monocytic cells by glutathione, gluthatione ester and n-acetylcysteine. proc natl acad sci usa 1991; 88: 986-90. 12. kinscherf r, fischbach t, mihm s, et al. effect of glutathione depletion and oral n-acetyl-cysteine treatment on cd4+ and cd8+ cells. faseb j 1994; 1: 448-51. 13. leeuwenburg c, ji l. glutathione and glutathione ethyl ester supplementation of mice alter glutathione homeostasis during exercise. j nutr 1998; 128: 2420-6. 14. mackinnon l. advances in exercise immunology. champaign illinois, usa: human kinetics,1999: 314-5. 15. mcardle w, katch f, katch v. exercise physiology. 3rd ed. philadelphia, usa: lea and febiger, 1991: 214-6. 16. mudd s, levy h, skovby, f. disorders of transsulfuration. in: scriver c, beaudst a, sly w, valle d, eds. the metabolic basis of inherited disease. 7th ed. new york: mcgraw-hill, 1995: 1279-81. 17. nash l. can exercise make us immune to disease? the physician and sportsmedicine 1986; 14: 251-3. 18. nieman d. exercise immunology: future directions for research related to athletes, nutrition and the elderly. int j sports med 2000; 21: s61-8. 19. nieman d, johanssen l, lee j, arabatzis k. infectious episodes in runners before and after the los angeles marathon. j sports med phys fitness 1990; 30: 316-28. 20. noakes t. lore of running. 3rd ed. champaign, illinois: leisure press, 1991: 23,49. 21. peters e, bateman e. ultramarathon running and upper respiratory tract infections an epidemiological survey. s afr med j 1983; 64: 582-4. 22. peters e, goetzsche j, grobbelaar b, noakes t. vitamin c supplementation reduces the incidence of post race symptoms of upper respiratory tract infection in ultramarathon runners. am j clin nutr 1993; 57: 170-4. 23. peters e, anderson r, theron a. attenuation of increase in circulating cortisol and enhancement of the acute phase protein reponse in vitamin c-supplemented ultramarathoners. int j sports med 2001; 22: 120-6. 24. powers s, hamilton k. antioxidants and exercise. clin sports med 1999; 18: 525-36. 25. reid m, stokic d, koch s, khauli f, leiss a. n-acetylcysteine inhibits muscle fatigue in humans. j clin invest 1994; 94: 2468-74. 26. roitt i, brostoff j, male d. immunology. 4th ed. london, mosby, 1996: 6.16.13, 8.1-8.7. 27. rossouw j, rossouw f. the effects of lactate-correlated training on running performance: a pilot study. ajpherd 2000; 6: 38-47. 28. rowbottom d, green k. acute exercise effects on the immune system. med sci sports exerc 2000; 32: s396-s405. 29. shephard r, verde t, thomas s, shek p. physical activity and the immune system . can j sports sci 1991; 16: 163. 30. snider i, bazzarre t, murdoch s, goldfarb a. effects of coenzyme athletic performance system as an ergogenic aid on endurance performance to exhaustion. int j sport nutr 1992; 2: 272-86. 31. stolzenberg-solomon r, miller e, maguire m, selhub j, appel l. association of dietary protein intake and coffee consumption with serum homocysteine concentrations in an older population. am j clin nutr 1999; 69: 467-75. sports medicine vol 16 no.1 2004 15 32. van brummelen r. l-methionine: immune supportive supplement in hiv+ patients: a south african study. amino acids 2001; 21: 1-90. 33. wang s, chen h, sheen l, lii c. methionine and cysteine affect glutathione level, glutathione-related enzyme activities and the expression of glutathione s-transferase isozymes in rat hepatocytes. j nutr 1997; 127: 2135-41. 34. weight l, myburgh k, noakes t. vitamin and mineral supplementation: effect on the running performance of trained athletes. am j clin nutr 1988; 47: 192-5. 35. weiss c, kinscherf r, roth s, et al. lymphocyte subpopulations and concentrations of soluble cd8 and cd4 antigen after anaerobic training. int j sports med 1995; 16: 117-21. 16 sports medicine vol 16 no.1 2004 vitamin c jf-f introduction it is well established that prolonged exercise results in delayed-onset muscle soreness (doms) which peaks after 24 48 hours and subsides after 5 7 days.8 this has been attributed to actual tissue damage which occurs during repetitive contraction of muscle fibres. the damage has been shown to be further exacerbated when the eccentric component of contraction is increased, as occurs during downhill long-distance running when muscles are used in a braking motion.17,18,20 the comrades marathon, a gruelling 90 km downhill foot race from pietermaritzburg to durban, south africa, causes an intense, systemic, exercise-induced inflammatory response. as the evidence regarding the effect of vitamin c (vc) supplementation on systemic markers of inflammation following eccentric exercise is presently conflicting showing either no effect,10,11,14 an attenuation2,19 or evidence of an increased proinflammatory response,5,15 it was the purpose of this study to reinvestigate and extend on our previous study 15 on the effect of oral vc supplementation on markers of the acute phase response and muscle damage following ultramarathon running in a more extensive work. we therefore undertook to examine the effects of supplementation using higher and lower dosages of vc in the same event 2 years later. methods study design approval to conduct the study was obtained from the human ethics committee of the nelson mandela medical school of the university of kwazulu-natal. forty-five registered 4 sajsm vol 17 no. 1 2005 original research article augmentation of the acute phase response in vitamin csupplemented ultramarathoners correspondence: e m peters department of physiology nelson r mandela school of medicine private bag 7 congella 4013 tel: 031-260 4237 fax: 031-260 4455 e-mail: futree@nu.ac.za e m peters (phd)1 r anderson (phd)2 d c nieman (phd)3 1department of physiology, nelson r mandela school of medicine, university of kwa-zulu-natal, durban 2medical research council unit for inflammation and immunity, department of immunology, university of pretoria 3department of health and exercise sciences, appalachian state university, boone, usa abstract objective. to investigate the effects of vitamin c (vc) supplementation on the alterations in systemic markers of inflammation as a result of participation in a 90 km down run from pietermaritzburg to durban in 29 subjects who completed the 1999 comrades marathon. interventions. runners were divided into groups receiving 500 mg/day vc (vc500; n = 10), 1 500 mg/day vc (vc1500; n = 12) or placebo (p, n = 7) for 7 days before the race, on the day of the race, and for 2 days following completion. main outcome measures. each subject recorded dietary intake before, during and after the race and provided 35 ml blood samples 15 18 hours before the race, immediately post race, 24 hours post race and 48 hours post race. these were analysed for full blood count, vitamins a, c and e, glucose, c-reactive protein (crp), amyloid a, interleukin-6 (il-6) and interleukin-8 (il-8) concentrations. all post race concentrations were adjusted for plasma volume changes. results. analyses of dietary intakes and blood glucose and anti-oxidant status on the day preceding the race and the day of the race excluded carbohydrate intake or plasma vitamins e and a as significant confounders in the study. mean pre-race concentrations of serum vitamin c in vc500 and vc1500 groups (128 – 10.2 and 153 – 10.2 mol/l) were significantly higher (p < 0.01) than in the p group (83 – 10.8 mol/l) and confirmed the additional dietary vc intake of both groups. serum crp concentrations were significantly higher (p < 0.05) in the vc500 group than in the vc1500 and p groups. this finding was supported by similar trends in serum amyloid a, plasma il-6 and il-8. when the data from the two vc groups were pooled and the vitamin intake in the placebo (n = 7) and vc (n = 22) groups compared, crp concentrations in the vc groups were significantly higher at each of the post-race time points (p < 0.05). conclusion. these data confirm previous findings of a trend towards an enhanced pro-inflammatory response following vc intake ≥ 500 mg per day. vitamin c jf-f 5/3/05 8:43 am page 4 6 sajsm vol 17 no. 1 entrants for the 1999 comrades marathon signed informed consent forms and agreed to participate in the study. they were divided into 3 groups matched for age, gender, training status and expected race finishing time: (i) group 1 (placebo (p)) — placebo supplement (3 placebo tablets per day); (ii) group 2 (vc500) — one 500 mg vc tablet and 2 placebo tablets per day; (iii) group 3 (vc1500) — three 500 mg vc tablets per day. each subject was required to take 3 tablets per day over a 10-day period; 1 tablet with breakfast, lunch and supper on the 7 days preceding the race, the day of the race and 2 days following the race. the study was double-blinded and based on a 3 (3 groups) by 4 (4 blood samples) repeated measures design. on the day prior to the race, subjects were required to complete 24-hour dietary records of their intake both in terms of food and supplements, and to report for basic anthropometric measurements and blood sampling on the afternoon prior to the race at a time that coincided with their estimated finishing time (in order to avoid the effect of diurnal rhythms on hormone concentrations). within 30 45 minutes of completing the race, the subjects again gave 35 ml blood samples and were asked to detail their dietary and liquid intakes on the morning of the race and during the race. the blood sampling was repeated 24 hours and 48 hours after the race and subjects were asked to record their post-race dietary intakes for a further 36 hours after the race. dietary analyses intake of both food and nutritional supplements were analysed using the dietary manager computer program (program management, randburg, south africa). total daily carbohydrate (cho) and vc intakes during the 24 hours before the race, on the day of the race, and after the race, including intake derived from any additional cho supplements used by the athletes, were determined. treatment of blood venous blood samples collected in glass vacutainer tubes containing ethylenediaminetetraacetic acid (k3-edta) were used for determination of full blood counts. a 15 ml aliquot was allowed to clot at room temperature and centrifuged for 10 minutes; aliquots of serum were quick-frozen and stored at -70…c for later analysis of vc, c-reactive protein (crp) and amyloid a. the remainder was drawn into vacutainer tubes containing k3-edta and the plasma stored at -70…c for later analysis of vitamins e and a, glucose, and interleukin (il)-6 and il-8 concentrations. haematological analyses and adjustments full blood counts were performed on k3-edtatreated specimens using standard haematological procedures on an automated model (coulter electronics inc., hialeah, florida, usa). plasma volume changes were determined from preand post-race haemoglobin and haematocrit values using the method of dill and costill6 and all subsequent post-race concentrations (at 0, 24 and 48 hours) were adjusted for these plasma volume changes. serum acute phase reactants, vitamins c, a and e serum concentrations of the acute phase reactants, crp (normal range 0 5 g/ml) and amyloid a (normal range 6 8 g/ml), were measured using a nephelometric procedure (behring nephelometer ii) with reagents purchased from behringwerke ag, marburg, germany. vc was extracted from the serum using 20% trichloracetic acid and assayed using the 2,4-dinitrophenylhydrazine colorimetric method (sigma chemical co., st louis, mo, usa), while plasma concentrations of vitamins a and e were determined using standard high-performance liquid chromatography (hplc) procedures following repeated (x3) extraction with hexane and using vitamin a-acetate as the internal standard.4 plasma glucose, il-6 and il-8 plasma glucose concentrations were determined spectrophotometrically in pre-race, immediate, 24-hour and 48hour post-race samples. the plasma il-6 and il-8 analyses were part of a more comprehensive study on the cytokine profile of ultramarathon runners,11 but were adjusted for plasma volume changes in this report. these were assayed using quantitative sandwich enzyme-linked immunosorbent assay (elisa) kits provided by r&d systems, inc. (minneapolis, mn, usa). a standard curve was constructed using standards provided in the kits. the assays were twostep sandwich enzyme immunoassay procedures in which samples or standards were incubated in 96-well microtiter plates coated with polyclonal antibodies for the test cytokine as the capture antibody. following the appropriate incubation time, the wells were washed and a second detection antibody conjugated to horseradish peroxidase was added. the plates were incubated and washed, and the amount of bound enzyme-labelled detection antibody was measured by adding a chromogenic substrate. the plates were then read at the appropriate wavelength (450 minus 570 nm). the minimum detectable concentration of il-6 was < 0.094 pg/ml, and of il-8 < 10 pg/ml. statistical analyses data are reported as mean (– standard error of the mean (sem)). due to the small sizes of the groups and the large variability of the test result values within the groups, conservative non-parametric statistics were used. a kruskal-wallis test was used to compare the mean ranks of the 3 groups at each of the time points. if this revealed significance, a twotailed wilcoxon s two-sample test was used to establish whether the difference between the placebo group and the vc500 or vc1500 groups was significant (p < 0.05). the data in the vc500 and vc1500 groups were subsequently pooled and an independent, two-sample mannwhitney test was used to establish whether the placebo group (n = 7) differed significantly from the vc group (n = 22), irrevitamin c jf-f 5/3/05 8:49 am page 6 sajsm vol 17 no. 1 2005 7 spective of the dosage differences, at each time point. box and whisker plots were used to illustrate the variability around the medians of the 2 groups. a repeated measures analysis of variance (anova) procedure was used on the logged data to perform a profile analysis of each of the measured outcomes. these data were graphically represented using profile plots showing the estimated marginal means of the 2 groups as a function of time. spearman s correlation coefficient was used as a measure of association. statistical analysis was executed using spss inc (chicago, illinois) statistical software. results subject characteristics of the initial 45 athletes registered to participate, only 29 completely fulfilled the protocol requirements of the study. the characteristics of the subjects are given in table i. there were no significant differences between the three groups with regard to age, height, mass, body mass index, training status, and time taken to complete the ultramarathon. cho intake, plasma glucose and vitamins a and e mean (– sem) dietary cho intakes and plasma concentrations of glucose on the day preceding the race and on the day of the race are presented in table ii. cho intake just prior to and during the race averaged 401 (– 39) g and did not differ significantly between the groups. likewise, preand postrace plasma glucose (table ii), vitamin a and vitamin e concentrations (not shown) were not different between the 3 groups (p > 0.05). blood counts selected results of the full blood counts are given in table iii. packed cell volume and haemoglobin concentrations indicated a varied hydration status ranging from a mean per cent plasma volume drop of 1.7% in the vc500 group to 7.1% in the placebo group in the immediate post-race samples (table ii). although 72.5% of the sample (n = 29) presented with a decrease in plasma volume immediately following completion of the ultramarathon, the greatest majority (62.1% and 100%) presented with increases in plasma volume in the 24-hour and 48-hour post-race samples, respectively. the differences in plasma volume between the groups did not, however, reach statistical significance (p > 0.05). significant immediate post-race lymphopenia and neutrophilia were present in all 3 groups with recovery to normal values at 24 and 48 hours after completion of the race. the circulating neutrophil count was significantly lower in the vc1500 group (n = 12) in immediate post-race samples, while postrace lymphopenia was less pronounced in the vc1500 group, resulting in the immediate post-race neutrophil/lymphocyte ratio being lowest in this group (p < 0.05). mean monocyte levels rose significantly in all 3 groups as a result of the prolonged exertion and remained elevated for the 48-hour post-race period with no significant differences between the 3 groups. serum vitamin c the results of the serum vc concentrations in the three groups at the four time-points are shown in fig. 1. pre-race serum vc was significantly higher in the supplemented groups compared with the p group. the significant mean increase (42.6 µmol/l) in serum vc in the p group immediately post race was less in both of the vitamin-supplemented groups (19.3 and -2.84 µmol/l in the vc500 and vc1500 groups, respectively). at 24 and 48 hours after completion of the race the serum vc concentrations returned to close to pre-race values. circulating concentrations of plasma il-6 and il-8 the mean immediate post-race concentrations of the table i. subject characteristics (n = 29) characteristic mean (± sem) range age (yrs) 39.7 (– 1.3) 27 54 body mass (kg) 70.4 (– 2.0) 53.2 97.0 stature (m) 1.74 (– 0.02) 1.57 1.89 body mass index (kg/m2) 23.2 (– 0.5) 18.7 28.7 race time (hrs) 9.73 (– 0.18) 7.38 11.08 weekly training distance (km) 87.9 (– 4.92) 70 120 table ii. mean (± sem) dietary carbohydrate (cho) intakes and plasma concentrations of glucose on the day preceding the race and the day of the race plasma glucose cho (g) (mmol/l) day preceding the race placebo (n = 7) 399 (– 29.1) 4.69 (– 0.3) vc500 (n = 10) 499 (– 51.3) 4.95 (– 0.3) vc1500 (n = 12) 482 (– 42.2) 4.74 (– 0.2) day of the race placebo (n = 7) 315 (– 54.8) 6.14 (– 0.6) vc500 (n = 10) 353 (– 35.2) 6.47 (– 0.5) vc1500 (n = 12) 488 (– 65.7) 5.95 (– 0.3) fig. 1. mean (± sem) serum vitamin c concentrations before and after participation in a 90 km ultramarathon (# p < 0.01, two-tailed wilcoxon’s test, v. placebo at this time point). 200 160 120 80 40 0 pre 0h 24h 48h post post post placebo vc500 vc1500 s e ru m v it a m in c ( µ m o l/ l) vitamin c jf-f 5/3/05 8:49 am page 7 8 sajsm vol 17 no. 1 chemotactic cytokine, il-8, were more than 5-fold higher than mean pre-race concentrations and subsided to close to pre-race concentrations at 24 and 48 hours after completion of the race (table iv). plasma il-8 concentrations correlated strongly (r = 0.67) with absolute neutrophil numbers in the circulation (table iii). the increase in the mean circulating concentrations of il-8, observed immediately post-race, were greater in the 500 mg group than in the p group, but the difference did not reach statistical significance (p = 0.14). circulating il-6 concentrations showed a similar trend to that of il-8, with a greater than 20-fold increase in concentrations following completion of the downhill ultramarathon, which subsided within 48 hours. however, throughout the 48-hour recovery the mean concentrations of il-6 in the vc500 group remained elevated above those of the p group, but the difference did not reach statistical significance (p = 0.11). serum crp and amyloid a concentrations both acute phase proteins measured in this study revealed a similar trend (figs 2 and 3). when concentrations in the 3 groups were compared at the 24 and 48-hour post-race timepoint a kruskal-wallis test revealed a significant difference in the circulating crp concentration (p < 0.05). similar trends were observed for amyloid-a, but were not statistically significant due to large intra-group variance. a subsequent wilcoxon s two-sample test revealed significant differences (p = 0.03; 0.04) between the vc500 and p groups for serum crp at the 24 and 48-hour post-race time-points. however, the increments in mean crp concentrations were not signiffig. 2. mean (± sem) serum crp concentrations before and after participation in a 90 km ultramarathon # p < 0.01, twotailed wilcoxon’s test, v. placebo at this time point). pre 0h 24h 48h post post post s e ru m c r p (m g /l ) 80 60 40 20 0 placebo vc500 vc1 500 table iii. haematological profile. values as mean (± sem) post-race post-race post-race variable pre-race (0.5 1 hour) (24 hours) (48 hours) % pv change * placebo 7.11 (– 2.98) -2.23 (– 3.55) 9.45 (– 2.54) vc500 1.73 (– 1.80) 7.74 (– 2.26) 12.3 (– 2.25) vc1500 6,73 (– 2.24) 5.43 (– 2.64) 15.6 (– 2.23) total leukocytes(10 9 /l ) placebo 7.62 (– 1.07) 18.1 (– 2.5) 8.66 (– 1.03) 8.09 (– 1.04) vc500 7.96 (– 1.09) 16.6 (– 1.2) 9.37 (– 0.68) 7.75 (– 0.31) vc1500 6.52 (– 0.48) 14.2 (– 1.1) 8.14 (– 0.66) 7.24 (– 0.46) neutrophils (10 9 /l) placebo 4.43 (– 0.91) 15.2 (– 2.2) 5.14 (– 0.13) 4.04 (– 0.79) vc500 4.82 (– 1.08) 13.8 (– 0.9) 5.64 (– 0.57) 3.59 (– 0.26) vc1500 3.45 (– 0.35)+ 11.0 (– 1.0)+ 4.43 (– 0.08) 3.10 (– 1.10) lymphocytes (10 9 /l) placebo 2.11 (– 0.12) 1.6 (– 0.3) 2.4 (– 0.3) 2.3 (– 0.3) vc500 2.21 (– 0.12) 1.3 (– 0.1) 2.6 (– 0.2) 2.2 (– 0.1) vc1500 2.25 (– 0.21) 2.0 (– 0.3)+ 2.7 (– 0.2) 2.4 (– 0.2) neutro/lymph ratio placebo 2.10 (– 0.37) 11.9 (– 2.3) 2.5 (– 1.5) 2.2 (– 1.1) vc500 2.31 (– 0.62) 10.7 (– 1.3) 2.4 (– 0.9) 1.7 (– 0.5) vc1500 1.53 (– 0.25) 7.0 (– 1.9)+ 2.0 (– 1.5) 1.5 (– 0.8) monocytes (10 9 /l) placebo 0.46 (– 0.05) 1.36 (– 0.15) 0.76 (– 0.10) 0.73 (– 0.10) vc500 0.61 (– 0.07) 1.00 (– 0.25) 1.00 (– 0.10) 0.76 (– 0.06) vc1500 0.61 (– 0.05) 1.05 (– 0.14) 0.79 (– 0.07) 0.79 (– 0.05) *calculated from packed cell volumes and haemoglobin concentrations; expressed as percentages relative to pre-race plasma volume. + p < 0.05 wilcoxon s test between groups at specified time-point when compared with placebo at this time-point. pv = plasma volume; neutro/lymph ratio = neutrophil/hymphocyte ratio. # # vitamin c jf-f 5/3/05 8:49 am page 8 sajsm vol 17 no. 1 2005 9 icant at any of the post-race time points in the vc1500 group. however when the data from the 2 vc groups were pooled (n = 22) and compared with the p group (n = 7), the mannwhitney test showed significant differences of serum crp concentrations between the 2 groups at 0 hours (p = 0.037), 24 hours (p = 0.048) and 48 hours (p = 0.048) post race. in terms of amyloid a, il-6 and il-8, the difference between the 2 groups was not significant at any of the time-points (p > 0.05). a box and whisker plot illustrating the variability around the median is provided in fig. 4 and indicates that the median of the p group did lie outside the interquartile range of the vc group at all 3 post-race time-points for serum crp concentrations. repeated measures anova showed no evidence of an interaction between the 2 groups over time for serum crp concentrations (p = 0.534). the effect of vc supplementation was significantly different from the p group at all time-points (f = 6.664, p = 0.016). the profiles of amyloid a and il-8 were identical, but co-incident (p = 0.458; 0.861). a profile plot of the logged serum crp concentration data is presented in fig. 5. discussion the results of the serum vc concentrations within the 3 groups confirm significant elevations in the supplemented groups when compared with those in the p group. in contrast, insignificantly different plasma glucose concentrations in the 3 groups following the race confirm the absence of this factor as a possible extraneous variable influencing vc uptake and absorption in the 3 groups.9 fig. 5. profile plot of the logged serum crp concentrations of the placebo (n = 7) and pooled vitamin c (n = 22) groups at the four time points. fig. 3. mean (± sem) serum amyloid a concentrations before and after participation in a 90 km ultramarathon. fig. 4. a box and whisker representation of the variability of the serum crp concentrations in placebo (n = 7) and pooled vitamin c (n = 22) groups at the four time points. pre 0h 24h 48h post post post pre 0h post 24h post 48h post a m y lo id a (m g /l ) 300 250 200 150 100 50 0 a m y lo id a (m g /l ) 120 100 80 60 40 20 0 -20 placebo vc500 vc1500 pre 0h 24h 48h post post post m e a n l o g s e ru m c r p (m g /m l) 2 1.5 1 0.5 0 -0.5 -1 placebo vitamin c placebo vitamin c table iv. mean (± sem) plasma interleukin-6 and interleukin-8 concentrations (adjusted for plasma volume changes) post-race post-race post-race variable pre-race (0.5 1 hour) (24 hours) 48 hours) il-6 (pg/ml) placebo 3.6 (– 2.4) 92.5 (– 22.3) 4.7 (– 2.4) 4.2 (– 1.2) vc500 3.5 (– 1.8) 112 (– 26.3) 6.8 (– 1.8) 4.5 (– 1.8) vc1500 2.5 (– 0.8) 73.1 (– 6.2) 6.5 (– 1.7) 4.2 (– 1.8) il-8 (pg/ml) placebo 4.0 (– 0.5) 22.1 (– 4.2) 3.6 (– 0.6) 3.4 (– 0.5) vc500 3.7 (– 0.7) 28.0 (– 6.6) 3.7 (– 0.7) 3.2 (– 0.7) vc1500 4.2 (– 1.8) 18.4 (– 2.0) 5.6 (– 0.9) 3.3 (– 0.4) vitamin c jf-f 5/3/05 8:49 am page 9 10 sajsm vol 17 no. 1 2005 when the results of each of the markers of transient systemic inflammatory response syndrome (sirs) measured in this study are considered collectively, participation in this 90 km downhill ultramarathon resulted in evidence of a substantial pro-inflammatory response which was confirmed by significant post-race elevations in neutrophil count, plasma il-6, il-8, serum crp and serum amyloid concentration. this evidence of sirs appeared to be exacerbated in the vc500 group when compared with the placebo and vc1500 groups. the development of an inflammatory reaction is known to be controlled by cytokines. while il-6 is released from activated t-helper-2 cells at the site of the damaged tissue, the chemokine, il-8, is known to mediate inflammation via its ability to attract and activate neutrophils in the damaged tissues3 and is a key player in the pro-inflammatory cytokine cascade. in this study, the mean increase in il-8 exceeded 500% and was accompanied by substantial increases in il-6, as well as the hepatically derived acute phase proteins, crp and amyloid a. despite the relatively small sample sizes of the 3 groups and the conservative non-parametric statistics used, serum crp, an important marker of acute phase response,7 was significantly elevated in the 24-hour post-race sample of the vc500 group when compared with the placebo group. this was supported by the trends towards higher serum amyloid a (p = 0.12), il-6 (p = 0.11) and il-8 (p = 0.14) post-race concentrations in the vc500 group. collectively, these data are also supported by recent findings. the significant increment in the 24-hour post-race acute phase protein concentration in the vc500 group confirms our previous finding of an increased acute phase response (crp) and reduced anti-inflammatory response (lower serum cortisol concentrations) reported in the group receiving 1 000 mg vc in our previous paper.15 the findings of childs et al.5 who showed that supplementation with the equivalent of 750 1 000 mg vc daily for 7 days prior to a brief, intense session of eccentric resistance exercise, resulted in significant increases in indices of oxidative stress which included serum-free iron, lipid hydroperoxides and 8-iso prostaglandin f2 alpha, also lend support to this finding. this contention is further supported by the significantly lower cortisol and anti-inflammatory cytokine (il-10 and il-1ra) response (reported in peters et al.14). notwithstanding the relatively small sample sizes and the fact that field work of this nature does not allow strict control of dietary intakes during the race, the trends of a pro-inflammatory response in the vc500 group are too striking to ignore and may well support in vitro findings of an ascorbic acid-induced pro-inflammatory response. these include inhibition of the hydrogen peroxide (h2o2), neutralising activity of catalase by complexing with the haeme group of this anti-oxidative enzyme,12,13 the inability of the vitamin to scavenge h2o21 and its paradoxical action in preventing the auto-oxidative inactivation of nadph-oxidase by acting as a scavenger of hypochlorus acid (hocl), which results in increased production of h2o2 by activated phagocytes.1 although a pro-inflammatory response could reasonably be expected to augment innate host defences against microbial and viral pathogens, possibly contributing to the lower incidence of post-race upper respiratory tract infection in vitamin c-supplemented ultramarathon athletes,16 this may, however, be offset by an increase in the potential threat of inflammationmediated tissue damage. acknowledgements we thank mrs tonya esterhuizen for assistance with the statistical computation of data reported in this paper. references 1. anderson r, lukey pt. a biological role for ascorbate in the selective neutralization of extracellular, phagocyte derived reactive oxidants. ann n y acad sci 1987; 498: 219-47. 2. ashton t, young is, davison gw, et al. exercise induced endotoxaemia: the effect of ascorbic acid supplementation. free radic biol med 2003; 35: 284-91. 3. baggiolini m. novel aspects of inflammation: interleukin-8 and related chemotactic cytokines. clinical investigator 1993; 71: 812-14. 4. bieri jg, tolliver tj, catignani gl. simultaneous determination of retinol and (tocopherol in serum and plasma by liquid chromatography. clin chem 1983; 29: 708-12. 5. childs a, jacobs c, kaminski t, halliwell b, leeuwwenburgh c. supplementation with vitamin c and n-acetyl-cysteine increases oxidative stress in humans after an acute muscle injury induced by eccentric exercise. free radic biol med 2001; 31: 745-53. 6. dill db, costill dl. calculation of percentage changes of blood, plasma and red cells in dehydration. j appl physiol 1974; 37: 247-8. 7. fallon ke the acute phase response and exercise: the ultramarathon as prototype exercise. clin j sport med 2001; 11(1): 38-43. 8. lambert mi, dennis sc. delayed onset muscle soreness. south african journal of sports medicine 1994; 1: 18-20. 9. malo c, wilson jx. glucose modulates vitamin c transport in small intestine brush border vesicles. j nutr 2000; 130: 63-9. 10. nieman dc, henson da, butterworth de, et al. vitamin c supplementation does not alter the immune response to 2.5 hours of running. int j sport nutr 1997; 7: 173-84. 11. nieman dc, peters, em, henson da, nevines ei, thompson mm. influence of vitamin c supplementation on cytokine changes following an ultramarathon. j interferon cytokine res 2000; 20: 1029-35. 12. orr cwm. studies on ascorbic acid. i. factors influencing the ascorbatemediated inhibition of catalase. biochemistry 1967; 6: 2295-3000. 13. pederson ew, ostowski k, ibfedt t, et al. effect of vitamin supplementation on cytokine response and on muscle damage after strenuous exercise. am j physiol cell physiol 2001; 289: c1570-5. 14. peters em, anderson r, nieman dc, fickl h, jogessar v. vitamin c supplementation attenuates the increase in circulating cortisol, adrenaline and anti-inflammatory polypeptides following ultramarathon running. int j sports med 2001b ; 22: 537-43. 15. peters em, anderson r, theron aj. attenuation of the increase in circulating cortisol and enhancement of the acute phase response in vitamin csupplemented ultramarathoners. int j sports med 2001a ; 21: 1-7. 16. peters em, goetzsche jm, joseph le, noakes td. vitamin c as effective as combinations of anti-oxidant nutrients in reducing the incidence of upper respiratory tract infections in ultradistance runners. south african journal of sports medicine 1996; 4: 23-7. 17. poulsen he, weiman a, salonen kn, et al. does vitamin c have a prooxidant effect? nature 1998; 395: 231. 18. schane ja, johnson sr, vandenakker cb. delayed onset muscle soreness and plasma ck and ldh activities after downhill running. med sci sports exerc 1983; 15: 51-6. 19. schmidt ka, steinhilber d, moser u, roth hj. l-ascorbic acid modulates 5-lipogenase activity in human polymorhonuclear leukocytes. int arch allergy immunol 1988; 85: 441-5. 20. sorichter s, puschendorf b, mair j. skeletal muscle injury induced by eccentric muscle action. muscle proteins as markers of muscle fibre injury. exerc immunol rev 1999: 5: 5-21 vitamin c jf-f 5/3/05 8:49 am page 10 sajsm vol. 28 no. 1 2016 11 original research the medial tibial stress syndrome score: item generation for a new patient reported outcome measure m winters,1 msc; m franklyn,2 phd; mh moen,3,4 md, phd; a weir,5 mbbs, phd; fjg backx,1 md, phd; ewp bakker,6 phd 1 university medical centre utrecht, rehabilitation, nursing science and sports department, utrecht, the netherlands 2 department of mechanical engineering, the university of melbourne, melbourne, australia 3 bergman clinics, naarden, the netherlands 4 the sportsphysician group, olvg west, amsterdam, the netherlands 5 aspetar orthopaedic and sports medicine hospital, doha, qatar 6 division of clinical methods and public health, academic medical centre, university of amsterdam, amsterdam, the netherlands corresponding author: m winters (marinuswinters@hotmail.com) background: there is no valid and reliable instrument that evaluates injury severity and treatment effects for medial tibial stress syndrome (mtss) patients. objective: the aim was to generate items for the mtss score, a new patient-reported outcome measure for patients with mtss. methods: the authors consulted experts in the field of mtss to generate items that measure the severity of mtss and to reach consensus on the relevance of items for the mtss score. this research consisted of a pilot study and two delphi rounds. the delphi approach entails the consultation of experts about a topic for which no evidence is available during which consensus is sought on this topic. additionally, 20 mtss patients appraised the mtss score on readability and comprehension. results: nineteen experts consented to participate, 13 of whom reached consensus. generated items address the following domains: ‘limitation in sporting activities’, ‘pain while performing sporting activities’, ‘pain while performing activities of daily living’ and ‘pain at rest’. patients with mtss confirmed the good readability and comprehension of the items. conclusion: this study supports the importance of items in the aforementioned domains while evaluating treatment effects in patients with mtss. keywords: shin splints, item generation, delphi technique, crosscultural translation s afr j sports med 2016;28(1):11-16. doi:10.17159/2078-516x/2016/v28i1a426 medial tibial stress syndrome (mtss) is one of the most common lower leg injuries in athletes and military personnel.[1,2] it is an overuse injury with pain along the distal medial border of the tibia that is thought to be due to overloading of the bone.[3] a recent systematic review highlighted a lack of good studies on the treatment of mtss.[4] one commonly used definition for mtss is provided by yates and white:[5] ‘the presence of exercise-induced pain along the posteromedial border of the tibia over five or more consecutive centimetres that is elicited by palpation’.[5] in previous research, numerous outcome variables have been used to assess treatment effects on mtss patients; e.g. visual analogue scales, global perceived effect scales, and time to recovery.[4] over the past two decades, the opinion of the patient has received increasing attention when determining treatment effects in clinical trials and practice. hence, the use of patient reported outcome measures (proms) has been recommended to quantify the effect of interventions in randomised controlled trials and clinical settings.[6] a recent systematic review on mtss showed there is a need for a standardised outcome measure as no validated outcome measures have yet been developed.[4] item generation is the first step in creating a new prom. therefore the aim of this study was to generate items for a new prom for mtss patients and have these items’ relevance and comprehension subsequently appraised by patients with mtss. this prom should evaluate severity and treatment effects, and also incorporate the perception of the patient. methods and materials the authors used a delphi consensus study to combine expert opinions and reach consensus. a delphi approach entails the consultation of experts about a topic for which no evidence is available. these experts are blind to the other experts involved in the study; thus their opinion are not influenced by other expert opinions. in a delphi study a consensus of opinion is sought from those regarded as experts in their fields. these expert opinions are solicited “blind”.[7-9] for this study the authors received permission from the local medical ethics committees of the provinces of utrecht (12-542/c) and zuid-holland (12-092). identifying and inviting mtss experts the authors aimed to include experts in the field of mtss who were currently actively involved in mtss research and who also had clinical experience with mtss patients. therefore they firstly identified experts in the field of mtss by contacting national sports medicine associations, (the american college of sports medicine, the american orthopaedic society for sports medicine, the australasian college of sports physicians, the british association of sport and exercise medicine, the canadian academy of sport and exercise medicine, the danish association of sports medicine, german federation for sports medicine and prevention, and the swedish society of exercise and sports medicine) and requested they provide the contact information of their key experts in the field of mtss. in addition, those who had published studies in the field of mtss were contacted. based on their network of clinical experts, the authors also approached a number of people in the netherlands. all experts were invited to participate by email. delphi study a pilot study among the experts in the authors’ own network (n = 9) was conducted prior to starting the study in order to generate preliminary items. this network consisted of sports physicians and sports physiotherapists in the field of mtss with whom collaboration had taken place in previous research projects in the netherlands. in the first round of the delphi study, all experts were requested to comment on the preliminary items and asked to suggest new items. mailto:marinuswinters@hotmail.com http://dx.doi.org/10.17159/2078-516x/2016/v28i1a426 12 sajsm vol. 28 no. 1 2016 original research in consecutive rounds, these new items were included. these experts were asked to indicate their level of agreement with regard to the inclusion of the preliminary items in the mtss score on a five-point scale: strongly disagree, disagree, no opinion, agree, strongly agree. they were also requested to suggest additional items. consensus was reached upon an item when 67% of the experts voted for its inclusion or exclusion.[6] the delphi study was completed when consensus was reached upon all items and no further items were proposed. no maximum number of rounds was set. after consensus was reached, all items were translated into dutch by a native dutch speaker with a medical background who was also proficient in english. appraisal by patients a sports medicine physician diagnosed mtss if exercise-induced pain along the posteromedial border of the tibia was elicited by palpation on the posteromedial border of the tibia over a length of five or more consecutive centimeters.[5] patients were eligible for participation when they were ≥ 16 years of age and had had symptoms for ≥ three weeks. when focal tibial pain, indicative of a stress fracture, or a medical history with a cruris fracture was present, subjects were excluded.[10] after item generation, the patients appraised the items in two rounds. in the first round, the authors asked 15 mtss patients to provide feedback on readability and comprehension using a semi-structured interview. they subsequently modified the items according to their feedback. in the second round, an additional five patients with mtss were requested to appraise the items. cross-cultural translation all the generated items for the mtss score were translated from dutch to english. steps one to four from the cross-cultural validation process, as described by sousa and rojjanasrirat[11] and beaton et al.[12] were performed. the translation contained forward and back-translations. a steering committee, in which the translators and all authors (except mf), were represented, reviewed both the forward and back-translations and decided on the final english version. the decision making process was based on consensus, which was reached when 67% of the committee members present agreed. in case consensus could not be reached for all items, the authors planned to have them translated again using different translators. [11,12] results twenty-one international and eleven dutch experts were invited to participate, 19 of whom consented to participate: four americans, four australians, one canadian, nine dutch and one from england. there were eight sports physiotherapists, six sports physicians, one podiatrist, one surgeon in sports medicine, one podiatric surgeon, one exercise and sports specialist and one biomedical engineer. figure 1 is the study’s flow diagram. one expert withdrew his participation during the pilot study and five were lost to follow-up during the second round of the delphi study. those experts (n = 13: 8 dutch, 3 australian, 2 american) with whom consensus was reached are named in the acknowledgements section, except for one expert (mf) who co-wrote this manuscript. the supplementary online material presents all the items generated. invited experts through national sports medicine associations (n=3); invited experts through past publications (n=8) invited dutch experts through previous collaboration (n=11) international experts who consented to participate (n=10; australia = 4; usa = 4; canada = 1; great britain = 1) pilot study dutch experts who consented to participate (n=9) first concept version (n=16 items: adl = 6; sports activities = 10) generation of items 3, 5, 9, 10, 11, 13 and 15 national experts who stopped participating (n=1) delphi study (n=18 mtss experts) round 1: 10 preliminary items were adjusted/deleted proposal of items 1, 2, 7, 8, 12 and 14 (international) experts who stopped participating (n=5)round 2: experts (n=13) reached consensus on all items on which consensus was sought (table 1) items 4 and 6 were proposed and included in the mtss score without expert consultation appraisal by mtss patients round 1 (n=14) round 2 (n=6) fig. 1. flow diagram and patients’ appraisal of the mtss score pilot study the pilot study included 16 items on the limitations of activities in daily life (adl) (n = 10) and sporting activities (n = 6). these items were scored from 0 to 4, with 0 indicating ‘no problem’ to 4 indicating an ‘extreme problem’. the remaining items: 3, 5, 9, 10, 11, 13 and 15 were developed during the pilot study. round 1 in round 1, the main feedback provided was that there were too many items related specifically to running and sporting activities. furthermore, participants proposed that each outcome should have a descriptor, which was accordingly included for all items. items on sprinting, uphill running, and sudden accelerations and decelerations when running were removed as suggested by the majority of the experts, as these items were irrelevant to mtss patients that do not usually run. items 1, 2, 7, 8, 12 and 14 were produced in round 1 (see appendices 1 and 2 for items in dutch and english). sajsm vol. 28 no. 1 2016 13 original research round 2 in this round, consensus was reached on all but two items. one item was proposed in the second round but did not reach the prevalidation stage. this item looked at provoking pain during hopping. this item was considered irrelevant for the study’s objective as most patients do not usually hop. two items (4 and 6) were suggested in round  2; however, these items were not included in the additional round of the delphi study. items 4 and 6 both cover pain during sporting activities. table 1 provides an overview of the final level of consensus reached for each item. consensus was reached on all items formulated in english. table 1: number of experts (n = 13) that agree/disagree with inclusion of an item in the mtss-score item strongly disagree disagree no opinion agree strongly agree % of experts that agree with inclusion 1. current sporting activities 1 2 10 92% 2. current amount of sporting activities 1 3 9 92% 3. urrent content of sporting activities 5 8 100% 4. pain while performing sporting activities not assessed in delphi study 5. time to onset of pain during sporting activities 1 4 8 92% 6. pain throughout sporting activities 1 not assessed in delphi study 7. pain throughout sporting activities 2 1 3 9 92% 8. pain after sporting activities 4 9 100% 9. pain while standing 2 1 6 4 80% 10. pain while walking 4 9 100% 11. pain while walking up or down stairs 6 7 100% 12. pain while performing common daily activities 1 1 4 7 85% 13. pain at rest 4 9 100% 14. pain at night 2 2 5 4 69% 15. pain to touch 1 1 4 7 85% contribution of experts who stopped participating during the study, five of the 19 experts did not respond to the authors’ attempts to seek contact and contributions from the project. the expert who stopped participating during the pilot study suggested, together with other experts, to use an item on the current content of sporting activity (item 3). in the second round of the delphi study, five experts discontinued responding to the authors’ emails. the first of these experts stated that the questionnaire was complete in the first round and therefore did not respond to the authors’ further emails. the second expert suggested including items on the current content of sporting activities (item 3) and current sporting activity (item 1). one expert suggested including an item on night pain (item 14), and on pain experienced after sporting activities (item 8). the importance of the latter was supported by one of the other experts who also withdrew their participation. the fifth expert suggested including an item that differentiated between the various types of pathophysiology (e.g. stress fracture, compartment syndrome, mtss) of shin pain. however, it was decided not to include this item in the delphi study as it discriminates between types of lower leg pain instead of the severity of perceived complaints. appraisal by patients (figure 1) fourteen patients (seven women and seven men) commented on the newly developed mtss score. they completed the questionnaire and provided feedback on the questionnaire’s readability, comprehension and ease of use. the first concept of the questionnaire was shaped according to the example of the visa-a questionnaire with a guide to continue or skip to the next item. to continue or to skip an item depended on whether the patient was still involved in their usual sporting activity, was involved in alternative sporting activities only, or was not involved in any sporting activity at all.[13] however, some of the patients did not understand this structure. therefore the preliminary mtss score was modified so that every patient had to complete all the items. item 15 was not well understood. this item was aimed at the measurement of pain on touch. it started with descriptors for three different degrees of touch followed by statements of when pain was induced at touch. this was changed by using the various degrees of touch (e.g. bumping, pressing, rubbing) in the response options. other patients’ suggestions concerned alternative words for pain. changes were made based on the feedback provided. in addition, six patients (three women and three men) provided comments on the updated mtss score. no further comments were made and the mtss score was considered ready for validation. the mtss score the mtss score consists of 15 items: current sporting activities, current amount of sporting activities, current content of sporting activities, pain while performing sporting activities, time to onset of pain during sporting activities, pain throughout sporting activities (item 6 of the total set, see appendices 1 and 2), pain throughout sporting activities (item 7 of the total set, see appendices 1 and 2), pain after sporting activities, pain while standing, pain while walking, pain while walking up or down stairs, pain while performing common daily activities, pain at rest, pain at night and pain to touch (table 1). 14 sajsm vol. 28 no. 1 2016 original research cross-cultural translation the mtss score was translated from dutch to english according to the appropriate guidelines.[11,12] all minor discrepancies between translators of the forward and back-translations were resolved at consensus meetings. the forward and back-translations of the mtss score were critically reviewed by a steering committee comprising of all authors and translators. the back-translation highlighted a few minor discrepancies between the forward translation and the original version: “i feel ...” instead of “i have ...” (items 9, 10 and 11). other discrepancies were seen in item 5 where ‘sporting activities’ was included in the response options. all discrepancies were resolved so that the english version was a correct cross-cultural translation of the original dutch version. discussion this study provides expert-generated and patient-appraised items for a new patient reported outcome measure for mtss. consensus was reached on all generated items that were included during the delphi study. items generated relate to limitation in sporting activities, pain while performing sporting activities, pain while performing activities of daily living and pain at rest. patients appraised the generated items as to their ease of understanding and relevance to the injury. in previous research, a great variety of pain scales were used and definitions of when patients have recovered differ greatly between studies. this hampers comparison of results across studies. this present study aimed to generate items for a new standardised instrument to evaluate treatment effects in mtss patients. furthermore, the mtss score meets the need for an instrument that evaluates effects and incorporates the perceptions of the patient. the mtss score was developed using the delphi technique, a widely used method to reach consensus among experts in fields for which no evidence is available. one of the most important advantages is that experts are unaware as to who their co-participants are. therefore the experts opinions are free from the influence of other panel members.[7-9] the strong aspects in this delphi study include the size of the expert panel and the wide variety of experts with different backgrounds. in addition, the items have been appraised by a total of 20 patients with mtss, in two rounds. although five experts stopped participating during course of the delphi study, all experts contributed to the development of the mtss score’s items. furthermore, the quality of the contributions were considered as more important than the quantity of the contributions. there were also some limitations in the current study. consensus was not sought on two items (items 4 and 6). these items were proposed in round 2. as five experts did not respond to the authors’ emails after round 1, there was concern that more experts may drop out in additional rounds, thus leaving little or no consensus on the items. these two items were appraised by the authors’ group and were found to be useful. the content validity for items 4 and 6 is acknowledged and therefore less supported by expert consultation. the authors are confident that their decision to not seek consensus on these two items enabled a broad consensus on all other items. in the delphi method, there is no widely accepted threshold for when consensus among experts is met. previous reports suggested using thresholds between 50% and 70%.[8,9] in this research project, it was decided to set the threshold at 67%; however, there was >75% agreement for all but one item.[7] a report on the validation study, in which items for the mtss score were selected and its reliability, validity and responsiveness is assessed elsewhere.[14] conclusion this study reports on the item generation process for the mtss score, a new patient-reported outcome measure for patients with mtss. the results support the importance of items in the domains of pain, limitations in activities of daily living and sporting activities while measuring the severity of mtss from the patient’s perspective. the items generated in this study cover all these domains. acknowledgements: the authors are very grateful for the valuable contributions of the expert panel members. the experts that participated in the final round of the delphi study were: carl barten, bpt; steef bredeweg, md, phd; fred hartgens, md, phd; shannon munteanu, phd; carol otis, phd; rodney pope, bpt, phd; steven rayer, mspt; michiel schipper, mspt; victor steeneken, msc; jack taunton, md, phd; joost vollaard, mspt; wessel zimmermann, md. we thank sophia stone and jesse tjebbes (forward-) and elmar kal, phd, and jacintha kal (back-) for their valuable cross-cultural translations. competing interests: no competing interests to be declared. funding: none. references 1. clanton  to,  solcher bw. chronic  leg  pain  in the athlete. clin sports med  1994 oct;13(4):743-759. [http://dx.doi.org/10.1177/1941738111426115] 2. taunton je, ryan mb, clement db, et al. a retrospective case-control analysis of 2002 running injuries. br j sports med 2002;36(2):95-101. [http://dx.doi. org/10.1136/bjsm.36.2.95] 3. moen mh, tol jl, weir a, et al. medial tibial stress syndrome: a critical review. sports med 2009;39(7):523-546. [http://dx.doi.org/10.2165/00007256-20093907000002] 4. winters m, eskes m, weir a, et al. treatment of medial tibial stress syndrome: a systematic review. sports med 2013;43(12):1315-1333. [http://dx.doi.org/10.1007/ s40279-013-0087-0] 5. yates b, white s. the incidence and risk factors in the development of medial tibial stress syndrome among naval recruits. am j sports med 2004;32(3):772-780. [http:// dx.doi.org/10.1177/0095399703258776] 6. dawson j, doll h, fitzpatrick r, et al. the routine use of patient reported outcome measures in healthcare settings. bmj 2010;340:c 186. [http://dx.doi.org/10.1136/ bmj.c186] 7. boyce w, gowland c, russell d, et al. consensus methodology in the development and content validation of a gross performance measure. physiotherapy canada 1993;45:94-100. 8. mckenna hp. the delphi technique: a worthwhile research approach for nursing? j adv nurs 1994 jun;19(6):1221-1225. [http://dx.doi.org/10.1111/j.1365-2648.1994. tb01207.x] 9. mckenna h,  hasson f,  smith m. a delphi survey of midwives and midwifery students to identify non-midwifery duties. midwifery  2002 dec;18(4):314-322. [http://dx.doi.org/10.1054/midw.2002.0327] 10. edwards ph jr., wright ml, hartman jf. a practical approach for the differential diagnosis of chronic leg pain in the athlete. am j sports med 2005;33(8):1241-1249 [http://dx.doi.org/10.1177/0363546505278305] 11. sousa vd, rojjanasrirat w. translation, adaptation and validation of instruments or scales for use in cross-cultural health care research: clear and user-friendly guideline. j eval clin pract 2011 apr;17(2):268-274. [http://dx.doi.org/10.1111/j.13652753.2010.01434.x] 12. beaton de, bombardier c, guillemin f, et al. guidelines for the process of crosscultural adaptation of self-report measures. spine (phila pa 1976) 2000 dec 15;25(24):3186-3191. [http://dx.doi.org/10.1097/00007632-200012150-00014] 13. robinson jm, cook jl, purdam c, et al. the visa-a questionnaire: a valid and reliable index of the clinical severity of achilles tendinopathy. br j sports med 2001;35:335-341. [http://dx.doi.org/10.1136/bjsm.35.5.335] 14. winters m, moen mh, zimmermann wo et al. the medial tibial stress syndrome score: a new patient-reported outcome measure. br j sports med 2015 oct 28. pii: bjsports-2015-095060. [http://dx.doi.org/10.1136/bjsports-2015-095060] http://dx.doi.org/10.1177/1941738111426115 http://dx.doi.org/10.1136/bjsm.36.2.95 http://dx.doi.org/10.1136/bjsm.36.2.95 http://dx.doi.org/10.2165/00007256-200939070-00002 http://dx.doi.org/10.2165/00007256-200939070-00002 http://dx.doi.org/10.1007/s40279-013-0087-0 http://dx.doi.org/10.1007/s40279-013-0087-0 http://dx.doi.org/10.1177/0095399703258776 http://dx.doi.org/10.1177/0095399703258776 http://dx.doi.org/10.1136/bmj.c186 http://dx.doi.org/10.1136/bmj.c186 http://dx.doi.org/10.1111/j.1365-2648.1994.tb01207.x http://dx.doi.org/10.1111/j.1365-2648.1994.tb01207.x http://dx.doi.org/10.1054/midw.2002.0327 http://dx.doi.org/10.1177/0363546505278305 http://dx.doi.org/10.1111/j.1365-2753.2010.01434.x http://dx.doi.org/10.1111/j.1365-2753.2010.01434.x http://dx.doi.org/10.1097/00007632-200012150-00014 http://dx.doi.org/10.1136/bjsm.35.5.335 http://dx.doi.org/10.1136/bjsm.35.5.335 sajsm vol. 28 no. 1 2016 15 original research appendix 1: item set in dutch as generated by the delphi study sportactiviteiten: voor militairen: marsen en marcheren zijn sportactiviteiten. 1) momenteel: beoefen ik al mijn gebruikelijke sportactiviteiten ☐ kan ik, door mijn scheenbeenklachten, minder dan mijn gebruikelijke sportactiviteiten doen ☐ kan ik, door mijn scheenbeenklachten, alleen alternatieve sportactiviteiten doen ☐ kan ik, door mijn scheenbeenklachten, geen enkele sportactiviteit doen ☐ 2) deze vraag gaat over de hoeveelheid van uw sportactiviteiten: ik heb het aantal keer dat ik sport per week niet aangepast ☐ ik heb het aantal keer dat ik sport per week teruggebracht met 1-25% ☐ ik heb het aantal keer dat ik sport per week teruggebracht met 26-50% ☐ ik heb het aantal keer dat ik sport per week teruggebracht met 51-75% ☐ ik heb het aantal keer dat ik sport per week teruggebracht met 76-100% ☐ 3) deze vraag gaat over de inhoud van uw sportactiviteiten: ik heb mijn sportactiviteiten niet aangepast ☐ ik heb mijn sportactiviteiten een beetje aangepast (±25%), bijvoorbeeld een beetje minder sprintwerk/sprongwerk, een beetje minder lang sporten ☐ ik heb mijn sportactiviteiten behoorlijk (±50%) aangepast, ik sport minder intensief; bijvoorbeeld veel minder sprintwerk/sprongwerk, minder lang achter elkaar hardlopen ☐ ik heb het merendeel (±75%) van mijn training aangepast, ik sport veel minder intensief; bijvoorbeeld geen sprintwerk/ sprongwerk, niet lang achter elkaar hardlopen, alleen kort durende lichte belasting ☐ ik kan geen enkele sportactiviteit doen vanwege mijn scheenbeenklachten ☐ 4) tijdens het sporten: heb ik geen pijn in mijn scheenbeen ☐ heb ik enige pijn in mijn scheenbeen ☐ heb ik veel pijn in mijn scheenbeen ☐ ik kan niet sporten vanwege de pijn in mijn scheenbeen ☐ 5) hoe lang, nadat u gestart bent met sporten, voelt u pijn aan het scheenbeen? ik heb geen pijn tijdens het sporten ☐ langer dan 15 minuten nadat ik gestart ben ☐ binnen 15 minuten nadat ik gestart ben ☐ direct nadat ik gestart ben ☐ ik kan niet sporten vanwege de pijn aan mijn scheenbeen ☐ 6) als u pijn heeft tijdens het sporten, en u gaat door met sporten, wat gebeurt er dan met de pijn? ik heb geen pijn tijdens het sporten ☐ de pijn neemt af ☐ de pijn blijft hetzelfde ☐ de pijn neemt toe ☐ ik kan niet sporten vanwegede pijn aan mijn scheenbeen ☐ 7) als de pijn aanwezig is wanneer u begint met sporten, en u gaat door met sporten, wat gebeurt er dan met de pijn? ik heb geen pijn tijdens het sporten ☐ de pijn verdwijnt binnen 10 minuten ☐ de pijn verdwijnt na 10 minuten ☐ de pijn verdwijnt niet ☐ ik kan niet sporten vanwege de pijn aan mijn scheenbeen ☐ 8) na het sporten: heb ik geen pijn ☐ verdwijnt de pijn binnen 12 uur ☐ verdwijnt de pijn tussen de 12 uur en 2 dagen ☐ blijft de pijn langer dan 2 dagen aanwezig ☐ ik kan niet sporten vanwege de pijn aan mijn scheenbeen ☐ 9) tijdens staan: heb ik geen pijn in mijn scheenbeen ☐ heb ik enige pijn in mijn scheenbeen ☐ heb ik veel pijn in mijn scheenbeen ☐ ik kan niet staan vanwege de pijn in mijn scheenbeen ☐ 10) tijdens lopen: heb ik geen pijn in mijn scheenbeen ☐ heb ik enige pijn in mijn scheenbeen ☐ heb ik veel pijn in mijn scheenbeen ☐ ik kan niet lopen vanwege de pijn in mijn scheenbeen ☐ 11) tijdens trap opof aflopen: heb ik geen pijn in mijn scheenbeen ☐ heb ik enige pijn in mijn scheenbeen ☐ heb ik veel pijn in mijn scheenbeen ☐ ik kan niet traplopen vanwege de pijn in mijn scheenbeen ☐ gewone dagelijkse activiteiten: bijvoorbeeld staan, wandelen, lopen, traplopen of fietsen. 12) tijdens gewone dagelijkse activiteiten: heb ik geen pijn in mijn scheenbeen ☐ heb ik enige pijn in mijn scheenbeen ☐ heb ik veel pijn in mijn scheenbeen ☐ ik kan geen gewone dagelijkse activiteiten doen vanwege de pijn in mijn scheenbeen ☐ pijn in rust: bijvoorbeeld zitten of liggen. 13) in rust is mijn scheenbeen: niet pijnlijk ☐ gevoelig ☐ pijnlijk ☐ heel pijnlijk ☐ 14) ’s nachts: heb ik geen pijn ☐ is mijn scheenbeen soms gevoelig ☐ word ik wakker van de pijn in mijn scheenbeen maar ik val snel weer in slaap ☐ kan ik door de pijn in mijn scheenbeen delen van de nacht niet slapen ☐ 15) pijn bij aanraking: ik heb geen pijn bij aanraking van mijn scheen ☐ ik heb alleen pijn wanneer ik de scheen stoot ☐ ik heb pijn wanneer ik op de scheen druk én wanneer ik de scheen stoot ☐ ik heb pijn wanneer ik over de scheen wrijf, er op druk én de scheen stoot ☐ 16 sajsm vol. 28 no. 1 2016 original research appendix 2: english cross-cultural translated item set as generated by the delphi study sportactiviteiten: for military: marching is considered to be a sporting activity. 1) presently: i perform all of my usual sporting activities ☐ i am forced to do less of my usual sporting activities due to pain in my shin ☐ i am forced to do alternative sporting activities only due to pain in my shin ☐ i cannot do any sporting activity due to pain in my shin ☐ 2) this question concerns the frequency of your sporting activities: i have not reduced the frequency of my sporting activities ☐ i have reduced the frequency of my sporting activities by 1-25% a week ☐ i have reduced the frequency of my sporting activities by 26-50% a week ☐ i have reduced the frequency of my sporting activities by 51-75% a week ☐ i have reduced the frequency of my sporting activities by 76-100% a week ☐ 3) this question concerns the content of your sporting activities: i have not adjusted my sporting activities ☐ i have adjusted my sporting activities slightly (±25%), e.g. slightly less sprinting and jumping, slightly decreasing the duration of my sporting activities ☐ i have adjusted my sporting activities substantially (±50%), my sporting activities are less intense, e.g. substantially less sprinting and jumping, decreasing the duration of running ☐ i have adjusted the majority (±75%) of my sporting activities, my sporting activities are substantially less intense, e.g. avoiding sprinting and jumping altogether, running for short periods of time, only short and light loads ☐ i cannot do any sporting activity due to my shinbone pain ☐ 4) while performing sporting activities: i have no pain in my shin ☐ i have some pain in my shin ☐ i have a lot of pain in my shin ☐ i cannot do any sporting activity due to my shin pain ☐ 5) how long, after you have started a sporting activity, do you feel the pain in your shin? i have no pain during sporting activities ☐ after 15 minutes, after i have started ☐ within the first 15 minutes after i have started ☐ immediately after i have started ☐ i cannot do any sporting activity due to my shinbone pain ☐ 6) in the case of pain being present during your sporting activity, and you continue the activity, what happens to your pain? i have no pain during sporting activities ☐ the pain decreases ☐ the pain remains unchanged ☐ the pain increases ☐ i cannot do any sporting activity due to my shinbone pain ☐ 7) if you feel pain in your shin when starting your sporting activity, and you continue the activity, what happens to your pain? i have no pain during sporting activities ☐ the pain disappears within 10 minutes ☐ the pain disappears after 10 minutes ☐ the pain does not disappear ☐ i cannot do any sporting activity due to my shinbone pain ☐ 8) after sporting activities: i have no pain ☐ the pain disappears within 12 hours ☐ the pain disappears between 12 hours to 2 days ☐ the pain remains present for longer than 2 days ☐ i cannot do any sporting activity due to my shinbone pain ☐ 9) while standing: i have no pain while standing ☐ i have some pain while standing ☐ i have a lot of pain while standing ☐ i cannot stand due to the pain ☐ 10) while walking: i have no pain in my shin ☐ i have some pain in my shin ☐ i have a lot of pain in my shin ☐ i cannot walk due to pain in my shin ☐ 11) while going up or down stairs: i have no pain in my shin ☐ i have some pain in my shin ☐ i have a lot of pain in my shin ☐ i am unable to walk up or down stairs due to the pain in my shin ☐ usual daily activities: e.g. standing, walking (up or down stairs) or cycling. 12) while performing common daily activities: i have no pain in my shin ☐ i have some pain in my shin ☐ i have a lot of pain in my shin ☐ i cannot do any common daily activity due to pain in my shin ☐ pain at rest: e.g. sitting or laying down. 13) at rest, my shin is: not painful ☐ sensitive ☐ painful ☐ very painful ☐ 14) at night: i have no pain ☐ my shin is sometimes sensitive ☐ i wake up sometimes because of the pain in my shin, but i can fall back asleep soon ☐ i cannot sleep due to the pain in my shin for parts of the night ☐ 15) pain while touching: i have no pain when touching my shin ☐ i have pain when i bump my shin ☐ i have pain when i press and when i bump my shin ☐ i have pain when i rub, press on and when i bump my shin ☐ original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license an analysis of specific batting demands in the women’s the hundred competition s nicholls, phd; j keenan, msc; am cresswell, bsc (hon); l pote, phd department of sport, outdoor and exercise science, university of derby, england corresponding author: l pote (l.pote@derby.ac.uk) the game of cricket was traditionally perceived to be a physically undemanding sport.[1] however, over the decades, there has been a substantial amount of research showing that this is not the case, and cricketers need to be well-trained to compete.[2,3] this is most likely due to the increased professionalism and evolution of the game from test (multiday) and one day matches to the t20 format. cricket has therefore gone through several makeovers to keep up with the times[4] and as a result, players are faced with shorter formats and packed schedules for their country, club, and franchise. more recently, the newest, shortest, and fastest format of the game, the hundred, has been introduced in the united kingdom, where eight teams with players from all over the world compete in the five-week competition. a typical ‘hundred’ match lasts approximately two and a half hours with each team facing 100 deliveries. bowlers can deliver either five or ten consecutive balls (known as ‘sets’, instead of the traditional ‘overs’) with a maximum of 20 balls per bowler per innings (e.g. one set = five deliveries). the match outcome is ultimately decided by the team that scores the most runs. similar to t20, the rules have been modified from traditional formats to provide an advantage to the batters.[4] the first 25 balls constitute a power play where only two fielders are allowed outside the circle (27.43m area around the pitch), and ‘no balls’ award the batting side a ‘free hit’ plus two additional runs. therefore, batting performance is an important aspect of the game and investigating the movement demands and physical requirements of batters is key for both coaching and strength and conditioning staff.[5] furthermore, one of the key drivers of developing the ‘the hundred’ is the potential benefit to the women’s game, with increased visibility, investment, and exposure opportunities for players.[6] the women’s game is growing, with 30% of cricketers overall and 60% of new cricketers in australia being female;[7] however, there is limited literature regarding the women’s cricket formats.[8] a significant amount of research has performed time-motion analyses to quantify the movement patterns of male batters in test (multi-day), one day and t20 matches.[5,9] findings indicate that the intensity of the game increases with the shorter formats and that batters perform at a similar intensity for one day matches and t20 matches respectively (table 1). additionally, this similarity was also shown when comparing time between deliveries and overs for international one day and t20 matches. average time between deliveries and overs for one day games was 32.70s and 79.80s respectively compared to 35.00s (between deliveries) and 75.00s (between overs) for t20 matches.[2,10] likewise, the running requirements of both formats of the game were shown to be similar in nature.[2,10] while literature related to the movement demands for the multi-day, one day and t20 formats is substantially available, the same cannot be said for the hundred competition. to the authors’ knowledge, these studies have also not considered all variables that could affect these movement patterns, such as power plays, bowler/batter referrals (to the third umpire), strategic time outs, rain delays and injury time, which are important if the actual demands of the game are to be shown. furthermore, it has been indicated that these movement patterns are likely to differ between males and females because of factors such as anthropometry, force velocity relationships, boundary size, the size and mass of the ball, as well as the speed of the ball being bowled.[11] lastly, to date, no research has examined the movement demands of elite females in any of the match formats. the purpose of this study was therefore to analyse specific batting demands and variables associated with background: no research has investigated the shortest format of the game of cricket, the hundred competition. furthermore, women’s cricket research is particularly limited, with most focusing on injuries and little literature investigating specific batting demands. these demands are important if training programmes are to mimic the game’s movement patterns. objectives: the purpose of this study was to analyse specific batting demands and variables associated with the women’s the hundred competition. methods: thirty-one matches from the women’s 2021 the hundred competition were analysed using hudl sportscode elite. variables analysed included: bowler type (seam or spin), free hits, no ball runs, reason for no ball (height/wide/front foot), run scored (0, 1, 2, 3, 4, 6), type of key event (fall of wicket, bowling referral, batting referral, umpire referral, bowling time out, rain delay, or injury) as well as time between deliveries and sets, overall and between the power play and non-power play. a total of 6073 deliveries were analysed. results: a significant difference (p<0.05) was observed for time between deliveries for spin bowlers (26.90±22.16 s) compared to seam bowlers(31.70±20.37 s) as well as time between sets for the power play (58.00±13.28 s) and nonpower play phases (63.70±42.00 s). additionally, in the power play, most runs were made up of “1’s” and “4’s”. in the nonpower play phase, “1’s” made up the biggest contribution of runs (as a percentage). conclusion: the fact that singles make up a significant portion of a typical match means that strength and conditioning coaches should incorporate high-intensity sprint-type training into training programmes to mimic these demands. keywords: the hundred, batting, cricket, batters s afr j sports med 2023;35:1-6. doi: 10.17159/2078-516x/2023/v35i1a15056 http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15056 https://orcid.org/0000-0001-5545-1421 https://orcid.org/0000-0002-6200-1418 https://orcid.org/0000-0002-7295-8061 https://orcid.org/0000-0003-0727-0014 original research sajsm vol. 35 no.1 2023 2 the women’s the hundred competition. this is important so that trainers and coaches can design scientifically based programmes that mimic the demands of the female version of the game. in future, this could help with player performance and may reduce the risk of injury. methods sample thirty-four matches (32 regular seasons, one eliminator and one final) from the 2021 women’s the hundred competition were selected for analysis. the competition took place between 21st july 2021 and 21st august 2021. three matches were excluded due to significant rain effects causing match abandonment (manchester originals v northern superchargers and trent rockets v oval invincibles) or video feed issues (trent rockets v northern superchargers) whereby match footage was unavailable. as a result, video footage from 31 of the collated matches was used for the final analysis. a total of 6073 deliveries were analysed. variables and procedure match variables related to bowler type (seam or spin), whether it was a free hit, no ball runs (1, 2), no ball reason (height/wide/front foot), run scored (0, 1, 2, 3, 4, 6), and type of key event (fall of wicket, bowling referral, batting referral, umpire referral, bowling time out, rain delay, or injury) were selected. in addition, the time between deliveries (defined as the exact video frame immediately before ball release from the bowler’s hand), the time between sets (defined as the exact video frame between the umpire calling ‘set’ and the following ball delivery release frame), and the number of instances analysed were collected. operational definitions for each variable were defined prior to the coding of match footage and were referenced during analysis to ensure consistency and accuracy of coding throughout. to collate the data of interest, a bespoke panel was created within hudl sportscode elite (hudl, usa) to code each game and associated variables of interest. all data were manually coded by the same individual, visually reviewed, checked for entry and logic errors post-completion (e.g. if a wide was bowled then an extra delivery had been coded), and subsequently collated into a microsoft excel spreadsheet for further analysis. reliability coded data were assessed for accuracy and reliability. in a similar manner to kubayi and larkin,[12] data from approximately 10% of the matches analysed were randomly selected to be re-coded by the same observer following a minimum two-week separation to negate observer remembrance. intra-rater reliability was assessed for each variable between the two coded timelines using a pearson’s r coefficient (time between deliveries and time between overs) or kappa statistic (remaining coded variables). all variables demonstrated perfect (kappa = 1.00) or near perfect agreement (pearson r > 0.99) and provided confidence that the collected data reliably represented observed match events. statistical analysis descriptive data were presented as mean (sd) or relative contribution (%) where appropriate. normality assumptions were checked using the kolmogorov-smirnov test. a mann whitney u test (ibm spss statistics, version 25) was used to identify differences in the overall time taken between deliveries in relation to delivery type (spin vs seam), whilst a wilcoxon signed-rank test compared time between sets for power play and non-power play. statistical significance was set at p < 0.05. the friedman test was used to analyse the interaction between bowler type (seam/spin) and match period (powerplay/nonpowerplay) in relation to time between deliveries. post-hoc pairwise comparisons using the mann whitney u (wilcoxon rank-sum) test with a bonferroni correction were undertaken thereafter to minimise the risk of type i errors due to multiplicity testing. the effect size calculation (cohen’s d) was used to characterise the magnitude of difference for the time between deliveries and sets for the power play and the nonpower play phases, for both seam and spin bowling.[13] the criteria for interpreting effect sizes were: < 0.2 trivial, 0.2-0.5 small, > 0.5-0.8 medium, > 0.8 large. corresponding 95% confidence intervals (95% cis) were calculated. results a significant difference (p<0.001; es=0.23) was observed for the time between deliveries for spin (26.90±22.16s; 95% ci: 26.1127.66) compared to seam (31.70±20.37s; 95% ci: 30.94-32.42) bowlers overall. the friedman test indicated a significant interaction between bowler type (seam/spin) and match period (power play/non-power play (x2(3)=97.35, p<0.001; es=0.06). significant differences were identified for the difference in time between spin and seam within both the power play (26.20±17.68; 95% ci: 24.44-27.90; and 31.30±19.06; 95% ci: 30.18-32.45; u=375016.500; p<0.001; es=0.27) and the nonpower play (27.00±22.52s; 95% ci: 26.17-27.89 and 31.90±21.12s; 95% ci: 30.93-32.87; u=3111791.000; p<0.001; es=0.23) respectively (table 2). no significance was shown within each discipline (spin and seam) for all phases of the game as well as time between sets. dot balls (‘0’s) and ‘1’s’ respectively constitute 39.16% and 39.22% of runs per delivery bowled (table 3). in terms of run table 1. movement variables of male batters for the different game formats (adapted from petersen et al., 2010)9 sprints/hour (>5 m/s-1) mean sprint distance (m) maximum sprint distance (m) efforts/hour recovery ratio (1:x) twenty20 15 (9) 13 (4) 19 (6) 45 (16) 38 (13) one day 13 (9) 11 (3) 21 (11) 39 (16) 50 (21) multi-day 8 (3) 13 (7) 21 (8) 28 (6) 61 (10) data expressed as mean (sd). “efforts/hour”, number of movement efforts per hour; “recovery ratio”, ratio between work performed and recovery time. original research 3 sajsm vol. 35 no.1 2023 contribution ‘4’s’ make up the largest portion of runs scored in a women’s the hundred match (45.64% of total runs scored). within the power play (first 25 deliveries), dot balls make up the majority of the deliveries bowled (54.0% contribution), followed by ‘1’s’ (25.1% contribution) and ‘4’s’ (16.5% contribution; table 4). this changes outside of the power play (deliveries 26-100), where ‘1’s’ are more prevalent (44.3% contribution) followed by dot balls (33.8% contribution) and ‘4’s’ (12.7% contribution). more seam deliveries are bowled in the power play phase of the game compared to spin (67.2% vs 32.8%; table 5). the opposite is observed in the non-power play phase with seam deliveries making up 41.2% compared to 58.8% spin deliveries bowled. relatively, more wickets fall (6.1% vs 4.6%) and there are more umpire referrals (1.2% vs 0.4%) in the non-power play phase compared to the powerplay. contrastingly, more wides are bowled in the power play (5.4% vs 2.7% compared to the non-power play phase). discussion the most important finding of this investigation was that singles (1’s) made up the largest contribution (as a percentage) of running requirements for both the power play (25.1%) and non-power play (44.3%) phases of a women’s ‘hundred’ match (table 4). the same trend was observed overall, with 39.2% of running a result of singles (table 3). the use of singles to accumulate winning totals is different to the observed trend in men’s short form games where winning totals are built on ‘4’s’; more boundaries are scored in the men’s format.[14] significant differences (p<0.01) were also observed for time between spin and seam time deliveries (26.90±22.16s vs 31.70±20.37s; es=0.23), as well as time between spin and seam within the power play (27.00±22.52s vs 31.90±21.12s; es=0.27), and non-power play (27.00±22.52s vs 31.90±21.12; es=0.23) respectively. this is shorter than times observed for one day internationals (time between deliveries: 32.70s; time between overs: 79.80s) and t20 matches (time between deliveries: 35.00s; table 2. time between deliveries for spin and seam bowlers (overall, power play and nonpower play) as well as time between sets (5 deliveries) overall (s) power play (s) non-power play (s) spin 26.90 (22.16)* 26.20 (17.68) $ 27.00 (22.52) # seam 31.70 (20.37)* 31.30 (19.06) $ 31.90 (21.12) # both 29.20 (21.45) 29.60 (19.02) 29.00 (22.09) between sets 62.50 (37.71) 58.00 (13.28) 63.70 (42.00) data expressed as mean (sd). *, #, $, represent significant difference between paired symbols. one set is 5 deliveries. table 3. overall absolute runs and percentage run contribution for the 2021 women’s the hundred competition (n=31) run value number of deliveries delivery (%) total runs runs per set run (%) 0 2378 39.2 0 0.0 0.0 1 2382 39.2 2382 2.0 32.6 2 375 6.2 750 0.6 10.3 3 18 0.3 54 0.04 0.7 4 834 13.7 3336 2.8 45.6 6 86 1.4 516 0.4 7.1 extras* 240 272 0.2 3.7 overall 6073 100 7310 6.0 100 * extras are additional runs (1 or 2) provided to the batting team because of an in-match event (wides = 1 run, no balls = 2 runs). these extras do not form part of the total deliveries bowled by the fielding team. one set is 5 deliveries. teams may be bowled out prior to completing their allotted 100 balls or 20 sets in a match, or targets are chased down with balls/sets in hand. table 4. absolute and percentage (%) of deliveries and run contribution in the power play compared to the non-power play phase of the 2021 women’s the hundred competition (n=31) power play non-power play run value number of deliveries delivery (%) total runs runs per set run (%) number of deliveries delivery (%) total runs runs per set run (%) 0 874 54.0 0 0 0.0 1506 33.8 0 0 0 1 406 25.1 406 1.3 22.8 1974 44.3 1974 2.2 35.7 2 56 3.5 112 0.4 6.3 319 7.2 638 0.7 11.5 3 3 0.2 9 0.03 0.5 15 0.3 45 0.05 0.8 4 267 16.5 1068 3.3 60.0 567 12.7 2268 2.6 41.0 6 13 0.8 78 0.2 4.4 73 1.6 438 0.5 7.9 extras* 98 108 0.3 6.1 142 164 0.2 3.0 overall 1619 100 1781 5.5 100 4454 100 5527 6.3 100 * extras are additional runs (1 or 2) provided to the batting team because of an in-match event (wides = 1 run, no balls = 2 runs). these extras do not form part of the total deliveries bowled by the fielding team. “power-play” refers to the first 25 deliveries and “non-power play” is the remaining 75 deliveries in an innings. one set is 5 deliveries. teams may be bowled out prior to completing their allotted 100 balls or 20 sets in a match, or targets are chased down with balls/sets in hand. original research sajsm vol. 35 no.1 2023 4 time between overs: 75.00s).[2,10] this could be due to several factors. the rules are designed to encourage quicker play, bowlers do not change end after ever set and penalties are enforced for slow set rates in ‘the hundred’ competition. if the bowling team does not complete their sets in an allocated time period, one fewer fielder will be allowed outside the 30yard (27.43m) circle for the remaining sets, thus encouraging teams to ‘get through their sets’ quicker. in addition, the current study was on elite female cricketers while the studies investigated elite male players; more boundaries are hit during the men’s game perhaps resulting in a longer time to return the ball to the bowler. more boundaries are also hit in the men’s format of the game due to greater maximum bat speeds and ball launch speeds.[11] additionally, the boundary is smaller (closer) for the female game compared to the male setup, which could also account for the shorter times in this investigation.[11] these findings create a unique insight into the women’s ‘hundred’ game. there is potentially a greater exposure to high-speed running for female batters than seen in their male counterparts. furthermore, the reduced time between balls, and more significantly between sets, reduces the rest period and creates a higher density of action for the female players than observed in the men’s game. one of the key facets of successful batting performance is the accuracy and execution of skill, which is pressured in short forms of the game.[15] if these factors are further pressured by an increased volume of workload and density of skill execution, batting performance could be impaired. prolonged batting with repeated shuttle running has been reported to impact high-order cognitive function and therefore affect decision-making, response selection, response execution and other batting-related executive processes.[16] these findings also support that the development of the players' sprint performance, and aerobic and anaerobic capacity will be vital to successful batting performance, this will facilitate both production of high intensity actions and recovery from these actions. further to this, players should be exposed to sport-specific training that includes repeated shuttle running incorporating skill execution; however, this should be particular to the format being played. batters are most prone to lower limb injuries (hamstring and quadriceps strains) because of high workloads and the high eccentric load due to the constant acceleration, deceleration and turning when sprinting between the wickets.[17,18] training plans for batters in the women’s ‘hundred’ should also focus on high-velocity force application and the development of eccentric training regimes so that players can cope with the stress placed on them when sprinting between the wickets.[3] this could improve overall performance, as well as reduce the risk of injury by delaying the onset of fatigue.[3] for other key run-scoring metrics, more ‘4’s’ are scored during the power play compared to the non-power play phase; the opposite is seen for ‘6’s’ (table 4). this is understandable as during the power play, more players need to be within the inner circle (27.43m) (30-yard circle) due to fielding restrictions and as a result more ‘4’s’ are hit. furthermore, this is important as research on t20 matches has shown that winning teams hit more boundary ‘4’s’ in the power play (first six overs).[14] more ‘6’s’ are hit in the non-power play as players often have to clear the boundary at the back end of an innings when the field is spread out (relaxed fielding restrictions); a trend that has been observed in t20 cricket.[14] the same can be observed for running ‘2’s’; more are scored in the non-power play phase as the fielding restrictions have been lifted, which allows more opportunity for multiple runs. several interesting findings were also observed when examining the key events that take place in a match (table 5). as a percentage of deliveries within the phase, more wickets are taken in the non-power play phase (6.1%) of the innings compared to the power play (4.6%). this is to be expected as either a team is being bowled out before the completion of the table 5. total, percentage (of overall balls bowled) and per game key events in the power play compared to the non-power play phase of the 2021 women’s the hundred competition (n=31) key event power play non-power play total number percentage of total deliveries (%) number per game total number percentage of total deliveries (%) number per game fall of wicket 75 4.6 2.4 270 6.1 8.7 umpire referral 6 0.4 0.2 52 1.2 1.9 bowling referral 8 0.5 0.3 26 0.6 0.8 batting referral 3 0.2 0.1 11 0.2 0.4 injury 1 0.1 0.03 2 0.0 0.1 bowling time out 0 0.0 0.0 45 1.0 1.5 free hits 5 0.3 0.2 20 0.4 0.7 no balls 10 0.6 0.3 22 0.5 0.7 wides 88 5.4 2.8 119 2.7 3.8 seam deliveries 1088 67.2 35.1 1833 41.2 59.1 spin deliveries 531 32.8 17.1 2621 58.8 84.6 “power-play” refers to the first 25 deliveries and “non-power play” is the remaining 75 deliveries in an innings. seam and spin deliveries refer to all key events, but exclude wides, no balls, and free hits. one set is 5 deliveries. teams may be bowled out prior to completing their allotted 100 balls or 20 sets in a match, or targets are chased down with balls/sets in hand. original research 5 sajsm vol. 35 no.1 2023 100 balls, or batters are trying to ‘hit out’ and score as many runs towards the back end of the innings thus resulting in more wickets falling. the same trend is shown for umpire referrals; more are observed in the non-power play phase (1.2%) compared to the power play (0.4%). this is most likely because batters are trying to maximise non-boundary scoring opportunities (e.g., 1’s and 2’s) in the non-power play phase (as the field is spread out) which results in several run-out opportunities and hence umpire referrals. furthermore, the fact that the wicket-keeper in the female format of the game is often standing up to the stumps (through observation), means that there are most likely more umpire referrals as a result of stumping chances. in terms of batting and bowling referrals, no difference was observed between the power play and nonpower play phases. seam deliveries make up 67.20% of deliveries in the power play compared to 32.9% spin deliveries; the opposite was observed in the non-power play phase (58.8% spin compared to 41.3% seam deliveries). this is similar to the literature examining professional t20 matches (indian premier league and english domestic league) which showed that there is no advantage to using spin bowlers in the power play.[19,20] it has been suggested that spin bowlers should be used in the middle overs to restrict the run rate when the field is spread out,[18,19] which seems to be the case in the ‘hundred’ as well. this could explain the increased amount of spin deliveries used in the non-power play phase. lastly, more wide deliveries are bowled in the power play (5.4%) compared to the non-power play phase (2.7%). this could be due to the fact that more seam deliveries are bowled in the first 25 balls (power play) when the ball is new and swinging, compared to when the spinners bowl later on in the match. practical applications and future research this study is important for the design of scientifically based strength and conditioning programmes. it is important that training programmes both develop the specific bioenergetics required to support the movement demands of the game as well as sessions that simulate match situations as closely as possible to ensure that players are prepared for the unpredictable nature of the game of cricket and skill execution under fatigue. this is particularly important in this version of the women’s game as it appears to have demands of volume and density of workloads that are beyond those experienced by batters in the men’s game. this investigation could allow for the design of protocols that mimic certain phases of play for training purposes. effectively designed programmes could also reduce the risk of injury and improve overall player performance and well-being. taking the results of this investigation into account, most of the runs are scored through boundaries (‘4’s). therefore, training should incorporate some form of range or power hitting. upper body strength and power are other physical characteristics that need to be developed if the boundary is to be cleared more often. furthermore, singles also contribute substantially to overall runs scored. as a result, training practices should focus on the rate of force development in the lower limbs to help with acceleration properties. this may similarly reduce the risk of hamstring strains due to the eccentric actions when accelerating, sprinting and decelerating while running between the wickets. additionally, the information gained from this study can be used for the design of a ‘hundred’ protocol that may be used for future research to take a more in depth look at the different responses of elite female cricketers. this could allow future research to examine, for example, the physiological and perceptual demands of the women’s ‘hundred’. lastly, a comparison between these findings and the male version of the competition is needed. therefore, future research should consider replicating this investigation using male ‘hundred’ cricketers to determine whether the movement demands and patterns differ between a male and female cohort. conclusion this is the first study to investigate the demands of the women’s “the hundred” competition. the most significant finding was that singles (1’s) make up the majority of the running requirements, for both the power play and nonpowerplay phases of a match. as a result, strength and conditioning coaches should focus on mimicking the demands of the game by incorporating high-intensity, shuttle running into their training programs. this may help with overall performance as well as reduce the risk of injury. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: lp and sn: project conception, data collection, data analysis, manuscript draft and review. jk and amc: data collection, manuscript review. references 1. fletcher j. calories and cricket. lancet 1955; 268(6875): 1165-1166. 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[doi:10.1080/24748668.2014.11868721] original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license “if money was no object”: a qualitative study of south african university office workers’ perceptions of using height-adjustable sitstand desks pj gradidge,1 phd; m phaswana,1 msc; jy chau,2 phd 1 centre for exercise science and sports medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 department of health sciences, faculty of medicine, health & human sciences, macquarie university, sydney, australia corresponding author: pj gradidge (philippe.gradidge@wits.ac.za) sedentary behaviour is a growing global public health concern. elevated levels of sitting time are associated with all-cause mortality and cardiovascular disease risk factors, especially among people who are not sufficiently active. [1] sedentary behaviour is defined as sitting or lying recumbent or such activities that result in energy expenditures of ≤ 1.5 metabolic equivalents. [2] obesity and related comorbidities have strong links with sedentary behaviour, particularly in low-income and middle-income countries (lmics), such as south africa, where populations continue to shift into obesogenic urban environments and adopt these sedentary lifestyles. [3] recent data demonstrate that the prevalence of south africans sitting ≥ eight hours per day is approximately 4.6% of the population, and this is mostly among those living in urban areas. [4] office workers in south africa are prone to sitting for long periods of time during vocational hours, [5] that are similar to highincome countries (hics) where employees are sedentary for at least two-thirds of the workday. [6,7] a recent systematic review using pooled data reported that interventions for reducing sitting in office workers have found small improvements in cardiovascular health, particularly with systolic blood pressure (−1.1 mm hg), body composition (body weight: -0.6 kg; body fat percentage: −0.3%; waist circumference: −0.7 cm, and lipid profile (high-density lipoprotein cholesterol: 0.04 mm) and insulin (−1.4 pm). [8] interventions in free-living environments, including workplaces, that target sedentary behaviour alone or in conjunction with physical activity, are effective for improving biomarkers associated with cardiometabolic risk profiles. [8] most of the sedentary behaviour interventions have been carried out in high-income countries and eurocentric populations. the evidence indicates that sit-stand workstations are effective in workplace strategies in high-income country settings. [8] little is known about the feasibility of this strategy in the context of low-middle income countries, possibly due to the comparatively longer duration of interventions conducted in the studies in high-income countries. [8] for example, an australian workplace intervention that included environmental modifications (sit-stand desks), messaging to encourage behaviour adjustment and health coaching observed significant reductions in occupation-related sitting time and cardiometabolic biomarkers at 3and 12-months. [9] south african workers (n=1954) recruited from 18 companies were estimated to have a high prevalence of non-communicable diseases due to the growing obesity epidemic in the country. [10] hene et al. also reported that 67% of workers in their study were overweight, while 77% were insufficiently physically active. [11] what is lacking, however, is the comprehension of how tools to disrupt occupation-related sitting are feasible for workers in south africa. to our knowledge, strategies using sit-stand desks have not been applied in the south african workplace and not in a university context in particular. therefore, we sought to target this knowledge gap by exploring the perceptions of south african university office workers regarding the feasibility of sit-stand desks to reduce sedentary behaviour at work. methods setting, design, participants and recruitment this study was conducted at the faculty of health sciences, university of the witwatersrand, johannesburg, south africa. the study aimed to assess the feasibility of an environmental modification to promote less sitting using sit-stand desks. on the 20th of november 2020, all office staff from one building in the faculty of health sciences were invited by email to participate in this study. of the thirty-two potential participants who were working in the office during the covid19 lockdown, 11 responded to the invitation and completed an online pre-screening survey. the email invitation included a participant information sheet and a consent form. ethical background: data from empirical investigations on the feasibility and acceptability of using sit-stand desks in an office-based setting in lowand middle-income settings are limited. objectives: to explore the perceptions of south african office workers towards using height-adjustable sit-stand desks to reduce sitting time during vocational hours. methods: self-reported sedentary behaviour and in-depth, semi-structured interviews were conducted in december 2020. thematic content analysis approach was used to develop themes. results: eleven office workers with a work-time sitting time of 8 (6-8) hours were interviewed (age 40.5 ± 12.6 years), most (91%) were female. the main themes emerged and included: overall impressions of the height-adjustable sit-stand desks; enablers versus barriers to using the desk and readiness to continue using sit-stand desks. conclusion: the findings of this research add to the evidence on environmental workstation modifications for reducing sedentary behaviour. further investigations on the efficacy of sit-stand desks are recommended in south african university office workers. keywords: sit-stand desks, university office-based workers, workplace, sedentary behaviour, south africa s afr j sports med 2022;34:1-6. doi: 10.17159/2078-516x/2022/v34i1a13881 mailto:philippe.gradidge@wits.ac.za http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13881 https://orcid.org/0000-0001-6261-2545 https://orcid.org/0000-0002-5917-1619 https://orcid.org/0000-0001-5225-1184 original research sajsm vol. 34 no.1 2022 2 approval was obtained from the university of the witwatersrand (ethics certificate number m190224). written consent was provided by all participants. the inclusion criteria included adults (aged above 18 years) with access to a desk or workstation within an office, the ability to communicate in english, the ability to walk or stand for at least 10 minutes, and individuals who worked in the office for at least three days a week. the sit-stand workstation consisted of a height-adjustable workstation (jumbo deskstand™, deskstand, south africa) that allowed office workers to vary their posture throughout the workday between sitting and standing for a period of two weeks. the participant’s workstation was set up by one of the investigators (mp) in the best ergonomic position in relation to the participant’s height and needs. upon installation, participants were educated on the benefits of standing-based work and interrupting sitting time. participants were provided with training on how to optimally set up the workstation for their own individual job roles. the participants were asked to disintegrate their sitting time by accumulating bouts of standing activities of at least 10 minutes initially and, then progressing to longer bouts of 30 minutes or more as the study progressed. data collection procedure participants were first asked to self-report their estimated time spent sitting (hours) in various aspects of sitting during work, commuting and at home using an adapted version of the workforce sitting questionnaire (wsq). [12] the wsq is reliable and has been validated for use in office-based workers. [12] the semi-structured interviews took 10-30 min each, and were all recorded and conducted in english. interviews were conducted by one researcher (mp) using a semi-structured interview guide (supplementary file 1) via microsoft teams or in-person between 1st of december 2020 to 19th february 2021 as preferred by the participants during the covid-19 pandemic. recorded audio files from the discussions were transcribed verbatim. all transcripts were checked against the recordings to verify accuracy and credibility, and grammatical editing was adopted where necessary. data credibility and trustworthiness the authors followed and adopted the eight “big-tent” criteria for excellent qualitative research in conducting this study. these criteria included a worthy topic, rich rigour, sincerity, credibility, resonance, significant contribution, ethical and meaningful coherence. [13] exploring the perceptions of using height-adjustable sit-stand desks was considered a worthy topic to inform environmental sedentary behaviour interventions in the south african context. regarding rich rigour, the authors followed the established methodology for data collection, processing, and analysis. sincerity was observed by the authors that confirmed that the interviews were transcribed correctly and processed using recognised software (atlast.ti) and that there was agreement on the themes and sub-themes to ensure optimal trustworthiness. credibility was confirmed by presenting the themes that could be anchored to participant quotations. the exemplar quotations are presented systematically for a visual resonance of the participants’ perceptions of using the heightadjustable sit-stand desks. concerning significant contribution, the authors describe the conceptual relevance of interrupt sitting time during office hours and the importance of informing further studies of environmental tools to reduce sedentary behaviour in the south african workplace. ethical approval was obtained as described. finally, meaningful coherence for this study was realised by ensuring robust methodology consistent with previous research of sedentary behaviour interventions in the workplace. [14] data analysis recordings were transcribed and de-identified by a professional service. all transcripts were read at least twice by each researcher and then coded line by line using a thematic analysis approach with atlas.ti 9 (9.1.5.0, atlas.ti scientific software development gmbh). two researchers (mp and pjg) read and coded the imported textual data to identify emergent themes. discrepancies were discussed, and revisions were made until full consensus was achieved. results the participants (n=11) were mostly female (91%) and had a mean age 40.5 ± 12.6 years (table 1). the majority had tertiary qualifications (91%) and 82% (n=9) were paid a monthly salary ≥r20000. the estimated self-reported sitting time ranged from table 1. demographic characteristics (n=11) characteristic n (%) age (years)* 40.5 ± 12.6 female 10 (90.9) highest level of education completed high school 1 (9.1) diploma/ college certificate 1 (9.1) university degree 3 (27.3) postgraduate degree 6 (54.4) monthly income prefer not to answer 1 (9) <r15000 1 (9) r15000-r19999 0 (0) r20000-r24999 4 (36) r25000-r29999 2 (18) ≥r30000 3 (27) estimated sedentary behaviour * occupational sitting (hours/day) 8 (6.0-8.0) sitting during commuting (hours/day) 1 (0.5-1.5) sitting at home (hours/day) 2 (2.0-5.0) total sitting time (hours/day) 10.5 (8.5-13.5) *data are expressed as mean ± sd or median (interquartile range). original research 3 sajsm vol. 34 no.1 2022 8.5 to 13.5 hours per day, with occupation-related sitting time contributing 76% to overall sitting time. table 2 presents the themes with illustrative quotes. overall impressions impact on ability to work all participants commented on the workstations bearing on their ability to carry out vocational tasks. the participants reported that reading and responding to electronic mail was more comfortable in the standing position, while typing activities were best suited to the seated position. ease of use participants expressed enjoyment about using the workstation during the study period, specifically commenting on the improved work productivity and the innovative approach to office work. in support, some participants felt that the workstation helped reduce work-related boredom and fatigue. enablers motivators while most of the participants had never experienced using an adjustable sit-stand desk, many described seeing comparable products advertised and expressed a desire to experiment using it in their own personal work environment. participants agreed that sitting for extended periods during work hours resulted in musculoskeletal pain in the lumbar and cervical regions of the spine. they were therefore interested in using the workstation and a treatment modality to manage the occupation-related pain. discussions revolved around the potential application of the unit in the workplace and for their individual administrative duties. while most participants felt that they were encouraged to take part, some participants agreed it was an opportunity to reorganise their immediate work environment. perceived physical health benefits multiple participants recognised the health benefits prompted by the adjustable sit-stand desk. the interruption of sitting time was perceived as an evidence-based approach to supporting suitable seated and standing ergonomics, despite lengthy periods of being sedentary. perceived work benefits for many of the participants, the adjustable sit-stand desk aided in improving their concentration during work responsibilities. throughout the interviews, the participants discussed the improved job performance with using the desk, and few described the concept of skeletal muscle memory to adopt the routine of alternating sitting and standing. perceived behaviour modification participants talked about the influence of the adjustable sitstand desks on their sitting and standing behaviour. they had various ideas about how the desks made them aware of the duration of sitting time and believed that they felt more active when they were in the standing position. some participants observed modifications in body position, such as a less slouched posture whilst in the standing position. table 2. themes with illustrative quotes theme illustrative quotes overall impressions it was a positive one, eh, user friendly, you know, you’d like, it was useful, it was easy to use, easy to move around with the thing. to move the screens, it was not hard work, if i am making any sense at all. (participant 1b89, female, aged 47 years) enablers i always, always try and keep like, if it's an invisible upright posture, i was trying to keep an upright posture even when i'm driving but my like, you know, rear mirror you know, being tilted a little bit higher up to force you to sit upwards and when i'm sitting at my table that kind of stuff ah, i'll be typing something and that kind of stuff in them in that moment represent we read over to make sure everything is fine, then i'll sit up straight like that. (participant a11, male, aged 24 years) obstacles/barriers i would have liked it if it had a one grade lower for the position of the laptop. so, i know that its design….it is not designed for laptop it is designed for a monitor but even at my eye level i did find myself having to adjust quite a bit, because it was slightly higher than what i was used to. not slightly higher, it was slightly higher than what eye level would be, but like i am talking centimetres here, because usually, you know, i am quite used to looking down at something. so that gradient from normally looking down and then all of a sudden eye level and slightly higher than eye level, it is a bit of an adjustment. so if it had, you know those that where you can adjust the levels of the platform, if it had it one lower that would have been perfect, from that bottom rung. (participant 1d53, female, aged 37 years) use of sit-stand workstation sitting vs. standing i used little shelves and like you said that novel hook was very nice, my phone i never needed to look for it because it’s always under paper. (participant 1b12, female aged 66 years) i stand a lot during the day so when you get a chance to sit down you take it (participant 87c, female, aged 24 years) readiness to continue using height-adjustable sit-stand desks look if money was no object, so if money was no object, and these things were for free, yes, i would definitely. and i'd probably i mean, if you could walk me into a factory or a store that had all these ergonomic stuff in and i could just take off the shelf and test it and put it on my desk, then probably what i would, i would set up my home station as well. my home station right now as a dining room table. and a dining room chair where the cushioning has gone, so i would set up, if money was no object, i'd set up home to be able to be flexible and move around. and then work, office work, i would definitely also set up permanently to be able to move around and do stuff. (participant 1e64, female, aged 52 years) original research sajsm vol. 34 no.1 2022 4 interestingly, the participants believed this position helped to reduce the chronic neck pain associated with typing for a long period of time while in a forward head posture, such as the sitting position at work. obstacles/barriers despite having the adjustable sit-stand desk arranged using an individualised ergonomic procedure, some participants argued that the design restricted modification and believed that their own personal computers were not considered in the development of the unit. others explained, with emphasis, that although the heightadjustable sit-stand desks improved work focus, the units failed to accommodate their usual connected devices, such as printers that needed to be connected by cable. physical discomfort for many of the participants, static standing for extended periods resulted in discomfort in the feet. some participants saw that a change from standing to sitting relieved this discomfort. one participant commented that the positional foot pain was managed by changing the standing position such as by shifting the body weight from one foot to the other. use of the sit-stand workstation: sitting vs. standing features/novelties for many of the participants, the notion of swapping between standing and sitting positions helped them to complete their tasks. for instance, participants perceived that they could complete tasks such as answering the telephone, responding to emails and conducting administrative duties in either sitting or standing positions. one participant felt that online meetings could be conducted in the standing position, while other participants believed that the sitting posture was best for answering the phone to respond to student queries. comfort although some participants described sitting to speak to staff and students on the telephone for five to ten minutes at a time, most of the participants reported being able to stand, intermittently for 15 to 30 minutes. some participants were able to extend the time spent standing from 60 to approximately 90 minutes at a time, while others indicated that the mornings were better for reducing sitting time because they were more attentive and enthusiastic. readiness to continue using height-adjustable sit-stand desks all participants in the study indicated that they would like to continue using the height-adjustable sit-stand desks if they were made available to staff. participants reported perceived improvements in work productivity and job satisfaction as the main reasons for supporting an initiative to reduce sedentary behaviour during work hours. some participants reported that affordability was a limiting factor for not purchasing their own workstation. discussion the aim of this study was to describe how office workers in a south african university setting viewed the feasibility of environmental modifications, and in this study, sit-stand desks for reducing sitting time in the context of the work environment. self-reported sitting time in the workplace was high yet aligns with previous data.[6,7] seven themes were developed including overall impressions of the heightadjustable sit-stand desks, motivation to experience the adjustable sit-stand desks, enablers of standing work using an adjustable sit-stand desk, use of sit-stand workstations, sitting versus standing, obstacles to using the adjustable sit-stand desk in the standing position, readiness to continue using sit-stand desks, and perceived behaviour modification. these themes are focused on healthy workplace behaviours and enhancements to occupational responsibilities, and they present an understanding of the way office workers perceive the promotion of interrupting sedentary time as essential. in agreement with existing evidence [8], data in our study showed a general acceptance of height-adjustable sit-stand desks to interrupt sedentary time without disrupting usual work responsibilities such as email communication and meeting attendance. other studies reported a different method to interrupt occupational sitting time, with participants using activities, such as walking between meetings, using the toilet, printer or getting coffee to break prolonged sitting. [15] consistent with our findings, a study that investigated the lived experiences of office employees with prior use of sit-stand workstations, [16] illustrated that the substitution of a traditional work model (task completion in the seated position) with a sitstand desk in the workplace can reduce vocational sitting time and improve productivity. additionally, previous research has reported participants’ variation in the usage of the sit-stand desk stands, with four studies stating the use of the workstation had no influence and three indicated that it enhanced productivity. [17] therefore, modifying the workspace by the alternative of between sitting and standing might be useful to reduce the monotonous feeling of fatigue and boredom. consistent with previous literature, our results indicated that the individual’s willingness to adopt the height-adjustable sitstand desks in their work environments were mostly precipitated by personal and organisational motives. [18] in addition, our findings highlighted that the personal and organisational influences for participation in this study were driven by curiosity to experiment with the compatibility of the workstation and other anticipated health benefits. participants with existing musculoskeletal conditions were motivated to participate in the study in order to attain perceived health benefits through the alternative between sitting and standing transitions. as noted in previous studies, our results show that participants spend most of their time at work seated, which makes them prone to adverse musculoskeletal conditions [19] alternating between sitting and standing positions was perceived as less comforting for work activity by some participants [20] however, the study by karakolis et al. [17] showed that working in the standing position was associated with chronic lumbar pain reduction in some employees. the original research 5 sajsm vol. 34 no.1 2022 acceptance of sit-stands desks in the work environment should nevertheless be investigated further as there might be resistance to change despite demonstrable improvement in physical health. consistent with previous research, [21, 22] participants in our study were also motivated to use the sit-stand desk because of the perceived benefits to musculoskeletal health, such as the reduction in chronic lower back pain due to the extended sitting time in the various domains of sedentary behaviour. occupation-related sitting contributed the most to overall daily sitting, a finding that has been observed in a number of systematic reviews investigating the sedentary behaviours of office workers. [8, 23] participants were also encouraged to use the workstations because of the incidental ergonomic intervention provided by the researchers during the initial setup of the workstations and continued engagement throughout the study. other studies have shown acute and chronic improvements as a result of the correction of working postures, [24, 25] but this needs to explored further in this study population. from the perspective of employee health, the findings of our study demonstrate that there were many occupation-related benefits that may be achieved through workplace interventions. specifically, some of the advantages described by participants included improvements in work productivity and mental concentration. indeed, in one study, improvements in task engagement in the erect position, despite there being reported discomfort. [20] evidence is inconsistent regarding productivity, one demonstrating that job performance was not hindered by standing work. [26] the present study’s findings observed that participants viewed the standing position as better for overall job performance compared to the seated position. these data illustrate that in the context of the office environment, tasks conducted in the standing position could also have varying influence on deliverables, depending on the task characteristics, duration allocated for task completion, and the expectations of line management. participants in the present study described improvements in attentiveness in the standing position compared to sitting for the completion of tasks, a finding which is in agreement with contemporary evidence. [27, 28] limitations this study has limitations worth noting, including the small sample size and the lack of information explaining why people declined to volunteer to participate in the study. participants in this study were university office staff, primarily women, with only one male who participated in the study, and may therefore not be representative of other office workers. in addition, breaks in sitting time were self-reported and no objective measures of free-living data were collected. the transport domain is important and travel to and from work could affect postural choice during the participant's work hours; however, understanding the nature of this domain is outside the scope of this feasibility study and should be examined in future research. this study was conducted during the stricter covid-19 lockdown measures in south africa, which limited face-to-face social interaction with the participants. however, the researchers continued engagement with participants using online and telephonic communication. this sample consisted of participants that presumably earn a monthly salary that is higher than other south africans and may therefore not be applicable to lowincome workers in lmics. finally, study participants provided information about musculoskeletal injuries that should be considered in future research studies. conclusion the participants in this study described their experiences using the height-adjustable sit-stand desk. the overall sentiment was that the workstation would be accepted in the workplace given the potential for sitting less, perceived improvements in productivity, and enhanced physical and mental health. the findings of this study suggest that there is a need for the modification of the occupational environment to reduce sitting time. conflict of interest and source of funding: the authors declare no conflict of interest. this research was supported by the south african medical research council [samrc], with funds received from the self-initiated research grant [sir] and the south african national research foundation (grant number 129565). acknowledgements: the authors acknowledge the study participants. author contributions: pjg and mp conceived the study design, analysed and interpreted the data and drafted the manuscript. jyc contributed to the interpretation of the data and editing of the manuscript. all authors read, edited and approved the final version of the article. references 1. ekelund u, steene-johannessen j, brown wj, et al. does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? a harmonised meta-analysis of data from more than 1 million men and women. lancet 2016;388(10051):1302-10 [doi:10.1016/s0140-6736(16)30370-1] [pmid: 27475271] 2. tremblay ms, aubert s, barnes jd, et al. sedentary behavior research network (sbrn) – terminology consensus project process and outcome. int j behav nutr phys act 2017;14(1):75 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macewen bt, macdonald dj, burr jf. a systematic review of standing and treadmill desks in the workplace. prev med 2015;70:50-8 [doi:10.1016/j.ypmed.2014.11.011] [pmid: 25448843] 27. magnon v, vallet gt, auxiette c. sedentary behavior at work and cognitive functioning: a systematic review. front public health 2018;6:239 [doi:10.3389/fpubh.2018.00239] [pmid: 30234085] 28. grunseit ac, chau jy-y, van der ploeg hp, et al. “thinking on your feet”: a qualitative evaluation of sit-stand desks in an australian workplace. bmc public health 2013;13(1):365 [doi:10.1186/1471-2458-13-365] [pmid: 23597291] sportsmed_june04 22 sports medicine vol 16 no.2 2004 introduction considerable physical and mental demands are placed on professional team sport players, with competitive events becoming more frequent and training schedules increasingly intense. in addition to exercise stress, a number of other stressors such as lack of sleep, mental stress, possible allergies to pollen or grass, frequent travel and prolonged exposure to ultraviolet (uv) radiation, also add to the demands of modern-day cricket. studies have shown that, in general, excessive exercise during training and competition leads to immunosuppression, or possibly a shift from cell-mediated to humoral immunity, especially in endurance-trained athletes.22,31,34 epidemiological studies on endurance athletes participating in long duration, competitive events2,13,21,23,31 have shown an increased incidence of upper respiratory tract symptoms (urts). although an earlier epidemiological survey of ultramarathon runners reported increased urts in faster runners,23 a more recent laboratory study of trained cyclists showed that in less extreme sports events, exercise duration has a greater suppressive effect on selected parameters of immune system function than exercise intensity.26 to understand these results more fully, it is necessary to consider findings of research at cellular level. studies have indicated that an acute bout of aerobic exercise decreased cd4:cd8 ratio during exercise, with a subsequent transient increase above baseline, post-exercise.17,27,30,33 however, strenuous training and competition over time may lead to chronically decreased cd4:cd8 ratios in athletes.1 specifically, baj et al.1 reported a significantly decreased cd4+ cell count accounting for the decrease in cd4:cd8 ratio in competitive cyclists after a 6-month season. this suggests a shift from specific immunity (cd4 cells) to nonspecific immunity (cd8 cytotoxic cells), or suppression of certain band t-cell mediated immune functions in these athletes. lymphocytes expressing the cluster differentiation markers cd4 (helper t), cd8 (suppressor/cytotoxic t), cd19 (b) or cd15/56 (natural killer (nk)) have undergone primary proliferation during the haematopoietic process and are usually in a quiescent state, and these cd markers may be used to identify the specific lymphocyte subpopulations. in response to mitogen exposure some of these cells will become activated and capable of secondary proliferation, which is vital for proper immune function. cells committed to secondary proliferation express cd69,14 which has been linked to their activation, proliferation and cytotoxic function.4,5,35 the wide celoriginal research article the effect of a professional cricket match schedule on selected immune parameters a w williams (mb chb, mphil (exercise science) k h myburgh (phd (physiology)) c smith (b tech (biomedical technology), mphil (exercise science)) department physiological sciences, university of stellenbosch, south africa abstract objective. the impact of a professional cricket match schedule on white blood cell (wbc) distribution and lymphocyte activation (cd69 expression) was investigated. methods. after a 3-month pre-season training period, physical and immune parameters were determined in 14 male cricketers before (b) and after (a) an intensive 5week match schedule. results. exercise test results were unchanged from b to a. total wbc counts were similar, but total lymphocyte and lymphocyte subpopulation counts decreased significantly. the cd4:cd8 ratio did not change. after in vitro stimulation, percentage cd4+cd69+ cells increased (b: 54.4 ± 9.7%, a: 64.0 ± 8.5%, p < 0.01), but absolute cd4+cd69+ cell counts did not change from b to a. in contrast, both the %cd8+cd69+ cells and absolute cd8+cd69+ cell count remained similar. conclusion. a strenuous, interregional, professional cricket match schedule resulted in a decreased number of lymphocytes, but relatively increased in vitro reactivity of cd4+ cells, thus maintaining the absolute capacity of the cd4+ cells to become activated on stimulation. in cricketers who suffered upper respiratory tract symptoms during the match schedule (n = 7), none of the immune parameters investigated differed significantly from the others at b or a. correspondence: c smith department of physiological sciences university of stellenbosch private bag x1 matieland 7602 tel: 021-808 4388 fax: 021-808 3145 e-mail: csmith@sun.ac.za sports medicine vol 16 no.2 2004 23 lular distribution of cd69 and its association with intracellular signal transduction8 suggest a central role for its expression in immune system function. few studies10,12,27 have investigated exercise-induced modulation of cd69 expression. ronsen et al.27 reported that 1 bout of cycling (65 minutes at 75% maximal oxygen uptake (vo2max)) did not significantly affect mitogen-induced cd69 expression in cd4+, cd8+ or nk cells. however, after 2 bouts of cycling separated by 3 hours, no effect was evident in the cd69 expression of cd4+ or cd8+ cells, but percentage of cd69+ nk cells was transiently decreased for 4 hours after the second bout. similarly, green et al.12 reported no change in the ability of cd4+ or cd8+ cells to become activated or to proliferate after a single 1-hour bout of treadmill running at 95% of ventilatory threshold. these study designs did not allow an assessment of the chronic effect of training in these elite athletes. in summary, the main conclusion that can be drawn from available research is that endurance exercise without sufficient rest between bouts seems to have only a transient inhibiting effect on nk cell activation and that chronic exercise training may cause a shift toward mobilisation of cytotoxic cell populations.18,19 however, monitoring of elite swimmers over 12 weeks of training11 showed no association between nk cell count and urti, suggesting that the humoral immune response may have a more significant role in protection from infection over a whole season. the longer-term effect of several weeks of strenuous exercise on cd69 expression in cd4+ and cd8+ cells has not yet been established in any exercise model. since activation and proliferation of lymphocytes are crucial for mounting an immune response against pathogens, it is important for athletes to understand the influence of their sport on the immune system, to assist in the prevention of illness. in competitive athletes exercise is not the only stressor, and effects of other possible additional stressors should be considered. for example, uv-b radiation has been shown to decrease lymphocyte function in in vitro culture studies,16 and to increase dna damage in mononuclear cells.15 also, lack of sleep, mental stress and frequent travel, which includes the risk of exposure to novel pathogens, have been named as additional factors which amplify the risk of infection in athletes.20 long-distance air travel has been reported to impair t-cell dependent cellular immunity,28,29 possibly due to cortisol-induced down-regulation of t-helper 2 cells.29 to begin to profile the cumulative effect of a variety of stressors, we studied athletes participating in a sport with frequent, long-duration match-play, with intermittent bursts of exercise, who also had a frequent schedule of matches, some requiring air travel. specifically, the effect of an intermittent, strenuous cricket match-play schedule lasting 5 weeks on lymphocyte subpopulation distribution and the expression of cd69 in cd4+ and cd8+ t-cells after in vitro stimulation was determined. a second purpose was to investigate whether these immune parameters (determined before and after the match-schedule) were associated with either the fitness performance of the subjects at the same time points, or urts experienced during the 5 weeks. methods subjects fourteen healthy, fit male cricketers (mean age 25.4 ± 4.8 years) from a regional professional cricket team completed the study (3 other recruited players were excluded due to injury sustained during the study). the subject group included 10 batsmen, 1 wicket-keeper-batsman, 5 fast bowlers and 1 spin-bowler batsman, thereby representing all positions in a cricket team. all subjects had been participating in cricket for more than 10 years, and had been playing professional cricket for an average of 4.9 ± 3.3 years. ethical approval was obtained from the university of stellenbosch before subjects gave voluntary, written, informed consent. initially, all subjects completed a health history questionnaire and underwent a general medical examination before the study. no subject reported a history of allergic reactions to grass or pollen, or of asthma. no pharmacological treatment was administered to any subject in the month prior to the study. exercise schedule the competitive season used as intervention in this study lasted 5 weeks and consisted of five 4-day provincial cricket matches with air travel (matches were played at venues ~2 000 km apart) and training sessions in between. a detailed description of exercise and training (volume and intensity) prescribed before and during the study period is given in table i. these schedules were prescribed and supervised by a professional biokineticist appointed by the team management. subjects kept a daily diary of health (including the following symptoms of urts: sore throat, runtable i. characteristics of the typical training volume and intensity prescribed for the cricketers in this study during each of the pre-season (pre-study) and the in-season (study) time periods sessions duration of total duration of % aerobic % anaerobic phase per week session (hrs) sessions (hrs) exercise exercise pre-season: gymnasium session 2 2 4 50 50 cricket training session 3 4 12 70 30 cricket match (regional) 1 6 (intermittent) 6 (intermittent) 50 70 30 50 in-season gymnasium session 1 3 3 100 0 cricket training session 2 4 8 70 30 cricket match (provincial) 4 6 (intermittent) 24 (intermittent) 50 70 30 50 ning nose, cough, sinus symptoms, headaches), intake of supplements and medication and reported to the team doctor on a weekly basis. these subjects were professional athletes and were used to reporting all health-related issues to the team doctor without delay. athletes participated in both home and away games and were therefore accommodated together and in their home environments during the month of the study. whether or not any family members had urts symptoms during the study was not recorded. fitness tests and blood sampling all measures were taken at two time points: before (b) and after (a) the 5-week schedule. vo2max was estimated using an incremental 20 m shuttle run (bleep test).24 strength and strength-endurance capacities were tested by bench press (1 repetition maximum (1-rm)) and pull-up count to exhaustion (maximum number of times a subject could pull up his own weight on a 2.5 m high cross bar). all subjects were familiar with the testing methods, since they were previously monitored regularly using these tests, which are the fitness tests prescribed by the united cricket board of south africa (although no scientific study exists to prove their suitability for assessing cricket fitness). blood samples were collected by venepuncture between 08h00 and 09h00, after a 12-hour fast, no high-intensity exercise for 48 hours, and no exercise at all for 24 hours. analysis edta blood samples were analysed for total and differential white blood cell (wbc) counts (coulter stks, beckman/ coulter, fullerton, ca, usa), and heparin blood samples for distribution of lymphocyte subpopulations by three-colour flow cytometry (facscalibur, becton/dickinson, new jersey, usa), using conjugated monoclonal antibodies (multitest, scientific products, johannesburg, sa). activation of cd4+ and cd8+ t-cells was determined by measuring their expression of cd69 after in vitro exposure to a stimulant, using the method described earlier by breytenbach et al.6 in short, aliquots of whole blood were stimulated for 4 hours (37ºc, 5% co2, 98% humidity) in the presence of phorbol 12myristate 13-acetate and a calcium ionophore, after which the cells were labelled with monoclonal antibodies specific for cd69 and measured using standard procedures for three-colour flow cytometry. statistical analysis results reported are means ± standard deviation (sd). data were compared using two-tailed, paired student's t-tests and repeated measures analysis of variance (anova) with bonferroni post hoc tests. associations between variables were determined using pearson's correlation analysis. significance level was set at p < 0.05. results average body mass and height of subjects were 82.7 ± 6.7 kg and 1.81 ± 0.07 m respectively. prescribed training and match hours increased from 22 per week during the pre-season to 35 per week during the study (table i). the main change in the components of training during this time were that weight training was removed during the season, and match-play hours, although intermittent due to the nature of the sport, increased from 6 to 24 hours. exercise test results remained similar for the duration of the study (table ii). mean total wbc count did not change, but mean total lymphocyte count, as well as all lymphocyte subpopulation counts analysed, were significantly decreased (table iii). specifically, cd4+ cells decreased by 21% and cd8+ cells by 16%, with no significant change in the cd4:cd8 ratio. however, % cd4+cd69+ cells increased significantly (b: 54.4 ± 9.7%, a: 64.0 ± 8.5%, p < 0.01), while the % cd8+cd69+ cells remained similar (fig. 1). the absolute number of cells activated per volume of blood did not change 24 sports medicine vol 16 no.2 2004 table ii. fitness performance of 14 professional male cricket players before and after intensive cricket participation lasting 5 weeks. no parameter changed significantly* parameter before after bleep test score 12 ± 1 12 ± 1 estimated vo2max (ml/kg/min) 52.8 52.8 bench press 1-rm (kg) 84 ± 10 83 ± 11 bench press : weight ratio 1.01 ± 0.09 1.01 ± 0.09 pull-up score 11 ± 4 10 ± 4 *values are means ± standard deviation. data were compared using paired student’s t-tests and significance was set at p < 0.05. 1-rm = 1 repetition maximum; vo2max = maximal oxygen consumption. table iii. selected immune parameters measured in 14 professional cricket players before and after a strenuous cricket match schedule of 5 weeks* wbc subpopulations (cells/ul) normal range before after significance total wbc 4 000 11 000 6 271 ± 1 333 5 607 ± 1 292 ns total lymphocytes 1 000 4 000 2 349 ± 664 1 865 ± 563 p < 0.005 total t-lymphocytes (cd3+) 1 100 1 700 1 626 ± 477 1 291 ± 450 p < 0.005 helper t-lymphocytes (cd3+cd4+) 700 1 100 949 ± 316 751 ± 223 p < 0.01 suppressor/cytotoxic t-lymphocytes (cd3+cd8+) 500 900 550 ± 196 463 ± 214 p < 0.05 ratio (cd3+cd4+:cd3+cd8+) 1.5 2.0 1.82 ± 0.49 1.79 ± 0.53 ns nk cells (cd3+cd16+/ cd3+cd56+) 200 400 379 ± 193 266 ± 152 p < 0.01 b-lymphocytes (cd3+cd19+) 200 400 304 ± 165 246 ± 103 p < 0.05 *values are means ± standard deviation. data were compared using paired student t-tests. wbc = white blood cell; nk = natural killer. sports medicine vol 16 no.2 2004 25 from b to a (fig. 2). the cd4:cd8 ratio correlated negatively with the bleep test score at both b and a (fig. 3). at b, the bleep test score correlated negatively with % cd4+cd69+ cells (r = – 0.45, p < 0.05) and tended to correlate negatively with % cd8+cd69+ cells (r = –0.42, ns). both these relationships no longer existed at a. six subjects each reported a short period (3 4 days) of urts that cleared up with symptomatic treatment administered by the team doctor. treatment consisted of either a nasal decongestant or oral anti-histamine, or both. one subject had diarrhoea that responded to an anti-diarrhoeal drug. none of the athletes discontinued training as a result of their symptoms. after dividing subjects into a symptomatic and an asymptomatic group, we found no effect of illness, and no interaction between illness and time (table iv), although the significant effect of time on % cd4+cd69+ cells was consistent with the data presented in fig. 1. discussion the main strengths of this study were firstly that it contributes to the few previous studies that have investigated the effect of participation in team sports on t-cell number and function7,25 secondly that the assessment of an activation marker on t-lymphocyte subpopulations was included in this study, and thirdly that the current results clearly indicate the importance of expressing immune function in absolute rather than in relative terms. previous longitudinal studies7,25 on football and soccer players showed that while the total wbc count remained unchanged, the cd4:cd8 ratio decreased over the course of a competitive season. the change in ratio was the result of an increase in cd8+ cells in the soccer players,25 but due to a decrease in the cd4+ cells in the football players.7 the results of unchanged total wbc count and decreased cd4+ cell count in the current study are in agreement with the study on footballers,7 whereas while the latter showed only a tendency for cd8+ cell count to decline, our study showed a significant decline. our study does not support the finding of an increased cd8+ cell count reported in soccer players. 25 the decreases in total lymphocyte, t-cell subpopulation, b and nk cell counts reported here, are similar to results obtained in earlier studies of endurance athletes.1,27,32 it is known that exercise-induced increases in concentrations of stress hormones, such as catecholamines,8 may be responsible for the exercise-induced depression of the lymphocyte counts.3,9 due to the nature of the game of cricket, all players are active for several hours each day when their side is bowling and fielding, and successful batsmen may also play for many hours on end, whilst those batsmen still to follow are under psychological stress. in cycling, the duration of exercise has been shown to be an important factor in altering the immune response.26 although not all cricket players have equally long duration of exercise, and the exercise is different from that of cycling, the cumulative stress during a single match may play an important role in their immune response. the additive effect of several long cricket matches may have significant effects that are quite different from those that may be seen after a single bout of a typical high-intensity, inter0 20 40 60 80 helper t suppressor t c d 6 9 e x p re s s io n ( % ) before after * 0 250 500 750 helper t suppressor t c d 6 9 e x p re s s io n ( c e ll s µ l1 ) before after c d 4 : c d 8 c e ll r a ti o 0.5 1.0 1.5 2.0 2.5 3.0 10 11 12 13 14 bleep test score before after fig. 1. percentage t-lymphocytes expressing the cd69 antigen after in vitro stimulation before and after a strenuous professional cricket match schedule of 5 weeks’ duration. values are means ± sd. (*value after significantly different from value before (p < 0.01)). fig. 2. average absolute number of t-lymphocytes expressing the cd69 antigen after in vitro stimulation before and after a 5-week strenuous professional cricket matchschedule. fig. 3. the association between estimated vo2max (from bleep test score) and helper:suppressor/ cytotoxic t cell ratio before (o, ---, r = –0.66, p < 0.01) and after (∆, ___, r = – 0.63, p < 0.01) the 5-week professional cricket matchschedule. 26 sports medicine vol 16 no.2 2004 mittent, short match duration team sport. taking into consideration that the athletes in the current study also trained on days between matches, the periods of rest may have been insufficient for the immune system to recover from the combination of physical and mental stress endured during matches, and the physical stress of training. exerciseinduced decreases in lymphocyte counts return to baseline levels only after 4 hours of recovery from acute exercise to exhaustion (lasting ± 1 hour).25 we hypothesise that exercise frequency may affect total lymphocyte and lymphocyte subpopulation counts found at rest in competitive athletes due to repeated transient increases in stress hormone levels and insufficient recovery. t-cell cd69 expression was also investigated. although both cd4+ and cd8+ cell counts decreased proportionally (cd4:cd8 ratio stayed similar), the %cd4+cd69+ on stimulation in vitro increased significantly. this is in contrast to the results of ronsen et al.27 who showed no change in %cd4+cd69+ cells when determined directly after a second bout of exercise performed on the same day. therefore, while a few acute bouts of exercise seem to have no effect on cd69 expression in cd4+ cells, many long-duration exercise bouts with additional cumulative stressors over 5 weeks resulted in significantly increased relative cd69 expression. although acute exposure of immune cells to uv-b radiation in vitro decreased lymphocyte function,16 t-cell function was not decreased in our study. one reason for this discrepancy could be a difference in the magnitude of radiation during the in vitro experiment vs. during actual outdoor sport participation. similar to extreme uv-b radiation, long-distance air travel also suppresses immune function.28,29 since we showed an increase in lymphocyte function, it is unlikely that the shorter duration air travel experienced by our subjects was a confounding factor. when considering the two main findings separately, the first finding of significantly decreased absolute counts of cd4+ and cd8+ cells at follow-up seems to indicate immune system impairment. but the second finding of an increased percentage of cd4+cd69+ cells seems to indicate that the immune system has an improved potential for functional response. the implication of both findings becomes clear only when put together, since the absolute number of activated cd4+ and cd8+ cells per volume of blood remained similar (cd4+cd69+ cells: b: 524 ± 210 vs. a: 487 ± 130 cells/ul; cd8+cd69+ cells: b: 136 ± 78 vs. a: 123 ± 84 cells/ul). therefore, although circulating cell numbers decreased, the percentage of cells activated to undergo proliferation increased (fig. 1), resulting in no net change in absolute cell reactivity (fig. 2). the bleep test score was negatively correlated with cd4+:cd8+ ratio at both b and a, so that a higher score was associated with ratios favouring the non-specific/cytotoxic tcell response, which is in accordance with previous reports in endurance athletes.18,19 in addition, the bleep test score correlated negatively with % cd4+cd69+ cells (r = –0.45, p < 0.05), and with %cd8+cd69+ cells (r = –0.42) before the competitive season. therefore players with better performance in an endurance test had lower relative cd69 expression at the start of the study. these relationships were no longer evident at follow-up, possibly due to changes occurring during the match period, e.g. illness or a change in fitness levels. however, results failed to show differences in cell reactivity between subjects who had experienced periods of illness and and those who had not (table iv), and fitness levels remained similar for the duration of the study (table ii). other possible explanations include similarities in psychological stress and the additional stress of air travel between match venues during the study as opposed to the pre-season period. the use of a suitable control group could have assisted in interpretation of data and strengthening of conclusions. however, selection of an appropriate control group would have been difficult for this study, and whether or not the investigators could control both their exercise habits and stress status for the duration of the study, in our case more than 2 months, is questionable. such a group would have to consist of equally fit, age-matched, non-smoking subjects, with similar air travel and sun-exposure schedules, and without any changes in life stress for the duration of the study. use of a non-suitable control group may also result in less accurate interpretation of results. for example, bury et al.7 used non-trained students as a control group for their study. such a group would be relevant for assessing exercise stress, but not any additive lifestyle stresses (such as examinations and social pressures). indeed, their control group showed slightly decreased cd8+ cell count (4%), which may have prevented the lowered cd8+ cell count seen in the footballers (15%) from reaching statistical significance, despite being of similar magnitude to the decline seen in cd8+ cell count in the cricket players in our study (16%). therefore, in the current study a control group was not used, and baseline samples served as controls, similar to other previous studies of long duration investigating similar parameters.10,25 table iv. effect of time and urts on cd69 expression in t lymphocytes* group 1: group 2: group 1: group 2: time group time-group urts healthy urts healthy effect effect interaction cell counts time: baseline time: follow-up significance (p-value) cd4+cd69+ (%) 53.5 ± 9.0 55.4 ± 11.1 66.6 ± 6.1 61.3 ± 10.1 0.01 0.67 0.31 cd8+cd69+ (%) 21.8 ± 10.6 24.1 ± 6.8 24.9 ± 6.2 23.7 ± 6.9 0.54 0.86 0.34 cd4+cd69+ (cells/ul) 515 ± 251 549 ± 207 454 ± 174 499 ± 94 0.30 0.66 0.91 cd8+cd69+ (cells/ul) 141 ± 92 136 ± 80 124 ± 82 122 ± 99 0.33 0.94 0.94 *professional cricket players were divided into two groups according to whether or not they had experienced upper respiratory tract symptoms (urts) during the 5-week study. data for 4 variables (relative and absolute expression of cd69 by helperand suppressor/cytotoxic t-lymphocytes) were analysed. values are means ± sd. statistical significance was tested using repeated measures 2-way analysis of variance (anova). sports medicine vol 16 no.2 2004 27 conclusion this study has shown that a 5-week strenuous, team sport match schedule had no net suppressive effect on cd4+ and cd8+ cell reactivity in response to mitogen stimulation, despite decreased circulating numbers of cd4+ and cd8+ cells. therefore, it is concluded that assessing absolute cd4+ and cd8+ cell counts may lead to incorrect conclusions about athletes' immune systems. it is proposed that potential capacity for lymphocyte function should be assessed by determining the absolute number of cells per volume of blood expressing cd69. acknowledgements this study was funded by the south african medical research council. references 1. baj z, kantorski j, majewska e, et al. immunological status of competitive cyclists before and after the training season. int j sports med 1994; 15: 319-24. 2. berglund b, hemmingsson p. infectious disease in elite cross-country skiers: a one-year incidence study. clin sports med 1990; 2: 19-23. 3. berk ls, nieman dc, youngberg ws, et al. the effect of long endurance running on natural killer cells in marathoners. med sci sports exerc 1990; 21: 207-12. 4. borrego f, alonso mc, galiani md, et al. nk phenotypic markers and il2 response in nk cells from elderly people. exp gerontol 1999a; 34: 25365. 5. borrego f, robertson mj, ritz j, pena j, solana r. cd69 is a stimulatory receptor for natural killer cells and its cytotoxic effect is blocked by cd94 inhibitory receptor. immunology 1999b; 97: 159-65. 6. breytenbach u, clark a, lamprecht j, bouic p. flow cytometric analysis of the th1-th2 balance in healthy individuals and patients infected with the human immunodeficiency virus (hiv) receiving a plant sterol/sterolin mixture. cell biol int 2001; 25(1): 43 9. 7. bury t, marechal r, mahieu p, pirnay f. immunological status of competitive football players during the training season. int j sports med 1998; 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91: 425-34. 28. rose dm, jung d, tamm w, keth a, loos ah. changes in cellular proliferation rate of lymphocytes after long-distance flights as a possible risk for patients with hiv-infection. eur j med res 2000; 5: 411 4. 29. rose dm, jung d, parera d, koniettzko j. time zone shift and the immune system during long-distance flights (abstract only). z arztl fortbild qualitatssich 1999; 93: 481 4. 30. shek pn, sabiston bh, buguet a, radomski mw. strenuous exercise and immunological changes: a multi-time-point analysis of leukocyte subsets, cd4:cd8 ratio, immunoglobulin production and the nk cell response. int j sports med 1995; 16: 446-74. 31. shephard rj. overview of the epidemiology of exercise immunology. immunol cell biol 2000; 78: 485-95. 32. shephard rj, shek pn. exercise and cd4+/cd8+ cell counts: influence of various contributing factors in health and hiv infection. exerc immunol rev 1996; 2: 65-83. 33. shephard rj, shek pn. infectious diseases in athletes: new interest for an old problem. j sports med phys fitness 1994; 34: 11-22. 34. smith ll. overtraining, excessive exercise, and altered immunity: is this a t helper-1 versus t helper-2 lymphocyte response? sports med 2003; 33: 347 64. 35. werfel t, boeker m, kapp a. rapid expression of the cd69 antigen on t-cells and natural killer cells upon antigenic stimulation of peripheral blood mononuclear cell suspensions. allergy 1997; 52: 465-9. original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the reliability of the scapular posture and scapular dyskinesis tests in rugby union players v singh,1,2 phd; k stokes,2 phd; g trewartha,2 phd; c mckay,2 phd 1 university of the west of england, bristol, school of health and social wellbeing, united kingdom bs16 1dd 2 university of bath. department for health, claverton down, bath, united kingdom of great britain and northern ireland ba2 7ay corresponding author: v singh (vincent.singh@uwe.ac.uk) synchronised activation of scapulohumeral muscles facilitate optimal shoulder function when tackling in rugby. [1] repeated collisions in rugby have the potential to alter this dynamic control, reducing the ability of the shoulder girdle to resist high deceleration forces at the point of impact, resulting in injury. [2] it is essential that clinicians are able to reliably assess scapular orientation and motion in players at risk of developing shoulder conditions and in those with shoulder pain. [3] the orientation (anterior tilting and downward rotation) and altered dynamic control of the scapular has been described as being associated with shoulder pain and the risk of injury. [4] alterations to the scapular position may be caused by multiple factors, with the large majority related to muscular imbalances and impaired motor control. [5] observation of the scapular in resting position can be performed by dividing it into multiple planes of reference, which is consistent with contemporary kinematic analysis. [6] separating the evaluation of the scapular into planes of motion has shown moderate interrater reliability (0.42) in 15 participants with neck pain. [6] a recent review demonstrated a lack of consistency in methods of assessing scapular orientation and varied results ranging from 14 out of 26 (54%) to 19 out of 26 (73%) when using the downs and black quality assessment tool. [7] in another study the test– retest reliability of this scapular posture rating assessment was investigated by five qualified physical therapists using 50 healthy participants. [8] the observed agreement between the test and retest ranged from 59% to 87% while the kappa values were inconsistent and showed fair to moderate reliability. the need for subjective judgement may limit the novice rater’s ability to identify impairments. therefore, o’leary et al. called for future research to investigate whether differences in the experience levels impacts inter-rater reliability. [6] the clavicle is part of the shoulder girdle and the clavicle tilt angle (cta) (angle between the horizontal and long axis of the clavicle) can influence scapular position and be useful in determining scapular orientation. [9] multiple impact forces to the clavicle in the rugby tackle may alter the cta, resulting in abnormal scapular orientation. clinical evaluation should therefore not overlook the importance of evaluating clavicle position. goniometric and photographic measurement of the cta is accessible in clinical practice, though there are no published normative data, which makes the clinical interpretation of the angular measurement unclear. scapular malposition and movement impairment is termed scapular dyskinesis (sd) which can be assessed clinically using visual observation including palpation, symptom alteration tests and with more advanced laboratory methods involving three-dimensional motion analysis. [10] the scapular dyskinesis test (sdt) is a visual observation protocol that has shown moderate inter–rater reliability (0.54) [11] and concurrent validity has been demonstrated with three-dimensional motion analysis; [12] however, these studies suffer from diverse test procedures and poor methodological quality. [13] the primary issue for the modest reliability findings is a lack of consensus of what constitutes a ‘normal’ scapular position, which inevitably influences judgement regarding abnormality. [6] there is also a paucity of rugby-specific evidence, which offers clinicians limited confidence to use these tests in a population that is exposed to repeated impacts to their shoulders with the propensity to result in injury. [14] the reliability of clinical tests requires sufficient time for conformity of performance, definitions and evaluations, which it can be argued should be gained with experience and may reflect inconsistent and unreliable ratings by novice raters. background: impact forces during rugby can contribute to scapula dysfunction and shoulder pain. reliable assessment of static and dynamic scapula position is paramount in managing athletes with, and those at risk of developing, shoulder pain. objectives: to determine the reliability of static scapular posture (sp), clavicular tilt angle (cta) and the scapular dyskinesis (sd) assessments by expert and student therapists. methods: the study design was an inter-rater and intra-rater reliability study in male university level rugby union players. four sport rehabilitation students and one experienced physiotherapist evaluated the position of the scapular and clavicle of male university-level rugby union players (interrater participants: session 1: n=17, session 2: n=12 and session 3: n=16; (intra-rater participants: n = 12). participants attended 3 testing sessions, each 1 week apart. scapular orientation and motion were assessed in five planes of movement and using the scapular dyskinesis test (sdt) respectively. the interrater analysis included all participants from each session, while in the intra-rater analysis included only the 12 participants who attended all three testing sessions. results: kappa coefficient values and percentage agreement ratings for students compared to the experienced therapist were: sp=poor to fair (-0.01 to 0.33), (27% 94%); sdt=slight (0.16; 41%); cta=fair (0.21; 59%). test-retest (intra-rater) agreement was fair to moderate (0.22 – 0.44; 69% 95%), slight (0.12; 47%), and fair (0.39; 77%) for the sp, sdt, and cta, respectively. conclusion: static and dynamic evaluation of the shoulder by students and an experienced therapist has poor to moderate reliability and should not be used to make clinical decisions based on observation alone. keywords: shoulder, musculoskeletal assessment s afr j sports med 2021;33:1-7. doi: 10.17159/2078-516x/2021/v33i1a11674 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a11674 https://orcid.org/0000-0002-9021-8956 https://orcid.org/0000-0001-7664-3211 https://orcid.org/0000-0001-8410-113x https://orcid.org/0000-0002-5049-2838 original research sajsm vol. 33 no. 1 2021 2 therefore, the purpose of this study was to assess the inter and intra-rater reliability between an expert therapist and student therapists of static scapular posture, clavicular tilt angle, and scapular dyskinesis tests in rugby union players within a realistic team setting. this research will further inform our understanding about the reliability of these tests when used by student therapists and their contribution in the clinical reasoning process applied in the prevention and management of shoulder complaints in rugby union players. methods participants and setting an interand intra-rater reliability study was conducted with four undergraduate final year sport rehabilitation students and one physiotherapist (15 years of musculoskeletal experience) who independently rated the static scapular posture, clavicular tilt angle and scapular dyskinesis of rugby union players. all students underwent one day of training to familiarise themselves with the testing procedures which were supervised by the physiotherapist prior to the test days. these students also completed 400 supervised clinical hours in the assessment and management of musculoskeletal conditions and also reviewed the literature pertaining to these tests as part of their research training over the past six months. participant characteristics participants were recruited during the competitive season (september to december 2015) from a squad of 60 players in a university men’s rugby union team (fig. 1). participant mean age was 21 years (standard deviation (sd)+/1.1 years) and mean weight was 91 kgs (sd +/7.9 kgs). players included in the study reported no current shoulder pain or shoulder injury in the previous six months and had full range of movement in shoulder abduction as screened by the physiotherapist using the painful arc test [15] before all three testing sessions. players were excluded if they did not meet these criteria. players had not trained 18 hours prior to testing. all participants volunteered and provided written informed consent. university of the west of england, bristol granted ethical approval for this study. procedure participants attended three testing sessions (session 1: n=17, session 2: n=12 and session 3 n=16), each one week apart. the inter-rater analysis included all participants from each session, while in the intra-rater analysis included only the 12 participants who attended all three testing sessions. each participant was randomly allocated to a rater upon arrival for testing in the sports changing room. the following tests were carried out on all three testing days: static scapular orientation, cta and the sdt. data collection was conducted at 17h00 before training which meant that raters had a short period in which to perform the assessments. each player’s profile was completed using a standardised baseline questionnaire that included a randomly generated participant number, date of birth and weight. the rater observed the participant’s scapular posture posteriorly by allocating one of three ordinal ratings in five planes of movement (fig. 2 and table 1). the rater then observed the participant from the front so that they could determine the cta. this measure was made by the rater observing whether the acromioclavicular joint was lower than, level with, or higher than the sternoclavicular joint. all ratings were made with participants standing in the anatomical position. the shoulder’s physical assessments were carried out fig. 1. flowchart of participation through the study fig. 2. scapular posture in five planes of movement including the scapular plane (a), sagittal plane (b), transverse plane (c), vertical and horizontal plane (d) original research 3 sajsm vol. 33 no. 1 2021 unilaterally for both arms with the participants barefoot, topless and wearing rugby shorts. to ensure that all raters observed the same repetitions of the dynamic movement during the sdt, the test was video recorded by a rater at all three testing sessions and the video was viewed and evaluated by all raters the next day. this dynamic test using dumbell hand weights, was done according to the procedure described by mcclure et al. (2009) using a video camera capturing a posterior view. the rating of the quality of movement for this test was scored independently for each arm and also independently rated by each rater using the operational definition for the scapular dyskinesis test described in table 2. statistical analysis inter-rater agreement was evaluated with weighted kappa and interpreted using the agreement measures for categorical data. [16] each student therapist’s (rater 1 to 4) rating was compared to that of the experienced therapist (vs, rater 5). intra-rater agreement was evaluated using an unweighted cohen’s kappa analysis. each shoulder was treated as independent with pooled data from the left and right ratings analysed for each plane and condition. [6] using the kappa coefficient when investigating nominal data can be influenced by the prevalence of responses in each category and bias within the data of paradoxical observations of high exact agreement and low kappa coefficients. [17] attempts to correct for this by adjusting table 1. criteria for rating scapular posture* rating criteria scapular plane upwardly rotated the inferior angle of the scapular was furthest away from the midline than the superior angle of the scapular. neutral the inferior angle and superior angle of the scapular was equidistant from the midline. downwardly rotated the superior angle of the scapular was furthest away from midline than the inferior angle of the scapular. sagittal plane anteriorly tilted the scapular has a prominently raised inferior angle relative to the thorax and the superior angle. neutral the scapular is positioned flat on the thorax with no prominent borders or angles. posteriorly tilted the scapular has a prominently raised superior angle relative to the thorax. transverse plane internally rotated the scapular has a prominently raised medial border relative to the thorax. neutral the scapular is rotated forward with no prominence of the medial border of the scapular relative to the thorax. externally rotated the scapular exhibiting minimal or no forward rotation in the transverse plane. vertical plane elevated the superior and inferior angle of the scapular superior to t3-4 and t7-9 respectively. neutral the superior and inferior angle of the scapular level with t3-4 and t7-9 respectively. depressed the superior and inferior angle of the scapular inferior to the t3-4 and t7-9 respectively. horizontal plane protracted the medial border of the scapular rests more than 5 cm from the midline. neutral the medial border of the scapular rests approximately 5 cm from the midline. retracted the medial border of the scapular rests less than 5 cm from the midline. *copyright © 2012 steven m. mcphail et al. (2014) this is an open access article distributed under the creative commons attribution license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. table 2. scapular dyskinesis test: description of operational definitions and rating scale* normal scapulohumeral rhythm stable scapular with minimal motion during the initial 30⁰ to 60⁰ of shoulder abduction, the scapular then moves smoothly and continuously rotating upward during abduction and smoothly and continuously rotates downward during adduction of the shoulder. no winging is present. scapular dyskinesis either one or both of the following abnormalities may be present. dysrhythmia scapular motion occurs prematurely or excessive elevation or protraction, during abduction or adduction of the shoulder the motion is not smooth or stuttering, or rapid downward rotation during adduction. winging the inferior angle and /or medial border of the scapular posteriorly displaced away from the thorax. rating scale (used for flexion and abduction) score description 1 normal motion is depicted by no evidence of abnormality 2 subtle abnormality is mild or questionable, not consistently present 3 obvious dysrhythmia or winging is striking, clearly apparent, evident on at least 3/5 repetitions rating scale (used for combined flexion and abduction test movements) score description 1 normal is both tests rated as normal or 1 motion is rated as normal and the other is subtle abnormality 2 subtle abnormality is both flexion and abduction is rated as subtle abnormality 3 obvious abnormality in either flexion or abduction is rated as obvious abnormality *permission granted by journal of orthopaedic & sports physical therapy, from mcclure p, tate ar, kareha s, irwin d, zlupko e . a clinical method for identifying scapular dyskinesis, part 1: reliability. journal of athletic training. 2009;44(2):160-164. original research sajsm vol. 33 no. 1 2021 4 the kappa coefficient have been suggested, but are criticised as representing an artificial coefficient when the dataset reflect real-life occurrences. in light of these issues, this study’s approach was to calculate the kappa coefficient and the exact agreement. all analyses were conducted using ibm spss statistics for windows, version 24.0. [18] results inter-rater reliability the reliability for the static scapular posture test ranged from 0.04 to 0.46 (table 3), which is poor to moderate agreement. agreement was higher between all raters in the sagittal plane (fair to moderate) than any other plane of movement. table 3. inter-rater agreement for scapular posture (weighted kappa values and percentage agreement) and mean agreement* plane of movement rater 1 versus 5 rater 2 versus 5 rater 3 versus 5 rater 4 versus 5 mean scapular 0.07 (34%) 0.04 (24%) 0.08 (30%) -0.04 (18%) 0.04 (27%) sagittal 0.22 (62%) 0.44 (78%) 0.21 (68%) 0.46 (73%) 0.33 (53%) transverse 0.00 (52%) 0.00 (50%) 0.00 (71%) 0.00 (52%) 0.00 (56%) horizontal 0.00 (93%) 0.00 (97%) 0.00 (92%) 0.00 (91%) 0.00 (93%) vertical -0.02 (93%) 0.00 (97%) 0.00 (97%) -0.02 (88%) -0.01 (94%) data expressed as weighted kappa (percentage agreement (%)). * a 0.00 score was calculated for ratings where the values were a constant and indicated perfect agreement. raters 1 to 4 are student therapists; rater 5 is an experienced therapist. table 4. inter-rater agreement for observation of clavicle tilt angle (weighted kappa values and percentage agreement) rater rater 5 weighted kappa standard error z value lower 95% ci upper 95% ci percentage agreement (%) 1 0.19 0.10 1.89 0.06 -0.00 0.38 58 2 0.27 0.10 2.55 0.01 0.07 0.47 62 3 0.04 0.06 0.67 0.50 -0.08 0.16 50 4 0.32 0.10 3.10 0.00 0.13 0.51 64 mean 0.21 59 raters 1 to 4 are student therapists; rater 5 is an experienced therapist. table 5. inter-rater agreement for scapular dyskinesia (weighted kappa and percentage agreement) rater rater 5 abduction flexion combined weighted kappa (percentage agreement) standard error weighted kappa (percentage agreement) standard error weighted kappa (percentage agreement) standard error 1 0.07 (57%) 0.09 0.16 (47%) 0.08 0.23 (47%) 0.07 2 0.08 (58%) 0.08 -0.02 (38%) 0.07 0.11 (43%) 0.05 3 0.30 (60%) 0.09 0.18 (48%) 0.08 0.24 (43%) 0.07 4 0.24 (43%) 0.09 0.14 (43%) 0.07 0.06 (32%) 0.06 mean kappa 0.17 0.11 0.16 percentage agreement 60% 44% 41% raters 1 to 4 are student therapists; rater 5 is an experienced therapist. table 6. intra-rater agreement of scapular posture (cohen’s kappa values and percentage agreement) and mean agreement* plane of movement rater 1 rater 2 rater 3 rater 4 rater 5 mean d1 vs d2 d2 vs d3 d1 vs d3 d1 vs d2 d2 vs d3 d1 vs d3 d1 vs d2 d2 vs d3 d1 vs d3 d1 vs d2 d2 vs d3 d1 vs d3 d1 vs d2 d2 vs d3 d1 vs d3 scapular 0.05 0.01 0.05 0.00 0.00 0.00 0.23 0.06 0.10 0.66 0.30 0.25 0.16 0.07 0.75 0.22 38% 67% 38% 79% 100% 79% 79% 83% 71% 83% 58% 58% 63% 58% 92% 70% sagittal 0.41 0.05 0.39 0.11 0.50 0.25 0.56 0.46 0.46 0.25 0.58 0.67 0.48 0.44 0.32 0.43 75% 63% 75% 67% 83% 75% 83% 75% 75% 63% 79% 83% 75% 75% 67% 74% transverse 0.14 0.42 0.24 0.52 0.78 0.33 0.00 0.09 0.00 0.28 0.43 0.60 0.27 0.25 0.10 0.34 63% 33% 46% 79% 92% 71% 92% 83% 92% 63% 71% 83% 58% 63% 42% 69% horizontal 0.11 0.65 0.07 0.00 0.00 0.00 0.48 0.48 1.00 0.46 0.06 0.65 0.00 0.00 0.00 0.44 79% 96% 83% 100% 100% 100% 92% 92% 100% 92% 88% 96% 100% 100% 100% 95% vertical 0.00 0.00 0.00 0.00 0.00 0.00 0.56 0.46 0.46 0.14 0.00 0.00 0.48 0.44 0.32 0.24 88% 100% 88% 100% 100% 100% 100% 100% 100% 75% 88% 79% 96% 100% 96% 94% data expressed as cohen’s kappa (percentage agreement (%)).* a 0.00 score was calculated for ratings where the values were a constant and indicated perfect agreement. raters 1 to 4 are student therapists; rater 5 is an experienced therapist. d1, day 1; d2, day 2; d3, day 3. original research 5 sajsm vol. 33 no. 1 2021 percentage agreement ranged from 18% to 97%. for the clavicle tilt angle (table 4), inter-rater reliability ranged from 0.04 to 0.32, which is slight to fair agreement. percentage agreement ranged from 50% to 64%. for sdt, inter-rater reliability for abduction ranged from 0.07 to 0.30, which was slight to fair agreement (table 5). flexion ranged from -0.02 to 0.18 (slight to fair agreement) and the combined movement ranged from 0.06 to 0.24 (slight to fair agreement). the percentage agreement ranged from 32% to 60%. intra-rater reliability for scapular posture, intra-rater agreement ranged from 0.00 to 1.00 (table 6). agreement of the clavicle tilt angle ranged from 0.02 to 0.65, which is slight to substantial agreement (table 7). for sdt, the intra-rater reliability for abduction ranged from -0.17 – 0.55, which was slight to moderate agreement. flexion ranged from 0.03 – 0.33 (slight to fair agreement), and the combined movement ranged from -0.17 – 0.51 (poor to moderate agreement) (table 8). the highest agreement was achieved by rater 1 ranging from 0.17 to 0.55 (slight to moderate reliability). discussion this was the first small field-based study to evaluate inter and intra-rater reliability between student and experienced therapists for the visual ratings of static scapular posture, clavicular tilt angle and the scapular dyskinesis in asymptomatic rugby union players’ shoulders. ratings showed a wide range of variability for all tests, yielding generally low reliability. visual observation of scapular posture varied up to 0.33 (weighted kappa) between different experience levels of raters in this study. the visual rating of the orientation of the scapular using the five planes of motion [8] as a reference did not have any better utility and did not improve reliability for the experienced or less experienced raters in this study. the inter-rater agreement was lower (mean kappa 0.16) than reported values in a study that used therapists with different experience levels for the scapular dyskinesia test (0.54). [11] in our study, raters were provided with test instructions and normal and abnormal motion was described to them; however, they did not train using actual examples of people with abnormal motion, which is considered inherently limiting. [11] the examples of abnormal motion used in training seem to be an important component, as does the length of training provided for raters. this was apparent in a recent study on 162 elite adolescent handball players which used two physiotherapy students to evaluate the inter-rater reliability for scapular control. [19] the raters in their study underwent two hours of training followed by two pilot testing sessions prior to data collection which involved 20 physiotherapy students in the first pilot and 45 youth handball players in the second. evidently their raters received significantly more training than the raters in our study, which may have been a factor in their greater k value (0.67 to 0.84) than in our study. routine practice of this clinical test is recommended for clinicians to reduce measurement errors. agreement for the sdt observed in this study was also lower than that found by novice raters (kappa=0.59) in a study that was published after our study was conducted. [20] that study was conducted on 40 patients with subacromial impingement and only used two novice raters. they concluded that there were wide confidence intervals with fair limits of agreement (0.38) when using the landis and koch [16] threshold and relatively large differences between the two novice raters for both interand intra-rater reliability. a large range in the upper and lower limits for results in that study was also found in our study, which indicates that the sdt is classified and interpreted differently by raters with different experience levels. using the operational definition in the sdt requires the rater to detect subtle variations of a number of types of dyskinesis which may not be easy to consider simultaneously. the determinants for the thresholds of dyskinesis are not clearly defined and equally may not be obviously apparent. for example, judging when the movement is premature or how much elevation or protraction table 7. intra-rater agreement for observation of clavicle tilt angle (cohen’s kappa values and percentage agreement) rater day 1 versus 2 day 2 versus 3 day 1 versus 3 1 0.52 (83%) 0.02 (54%) 0.05 (54%) 2 0.57 (79%) 0.50 (75%) 0.42 (71%) 3 0.03 (88%) 0.65 (96%) 0.21 (92%) 4 0.48 (79%) 0.49 (75%) 0.39 (71%) 5 0.58 (79%) 0.52 (79%) 0.48 (75%) mean 0.39 (77%) data expressed as cohen’s kappa (percentage agreement raters 1 to 4 are student therapists; rater 5 is an experienced therapist. table 8. intra-rater reliability for scapular dyskinesis (cohen’s kappa values and percentage agreement) and mean agreement scapular dyskinesis rater 1 rater 2 rater 3 rater 4 rater 5 mean d1 vs d2 d2 vs d3 d1 vs d3 d1 vs d2 d2 vs d3 d1 vs d3 d1 vs d2 d2 vs d3 d1 vs d3 d1 vs d2 d2 vs d3 d1 vs d3 d1 vs d2 d2 vs d3 d1 vs d3 abduction 0.55 0.30 0.18 0.26 0.47 0.19 0.02 0.09 0.06 0.26 0.03 0.29 0.20 0.13 0.01 0.20 79% 67% 63% 71% 79% 67% 50% 50% 50% 71% 63% 71% 71% 54% 46% 63% flexion 0.28 0.26 0.17 0.03 0.15 0.13 0.17 0.23 0.23 0.08 0.33 0.05 0.07 0.17 0.03 0.16 67% 54% 29% 58% 54% 29% 63% 58% 21% 46% 67% 46% 38% 42% 29% 47% combined 0.51 0.23 0.10 0.23 0.17 0.17 0.00 0.17 -0.02 -0.17 -0.08 0.03 0.07 0.02 0.31 0.12 75% 50% 42% 67% 58% 58% 42% 50% 25% 42% 42% 42% 42% 17% 58% 47% data expressed as cohen’s kappa (percentage agreement (%)). raters 1 to 4 are student therapists; rater 5 is an experienced therapist. d1, day 1; d2, day 2; d3, day 3 original research sajsm vol. 33 no. 1 2021 6 of the scapula is considered excessive. unless there is an obvious abnormality present, the likelihood of detecting a subtle abnormality may be low between raters or between time points. the study on elite adolescent handball players, previously mentioned, [19] used a modified version of the sdt test than that which was described by mcclure et al. (2009). the researchers modified the three-option categorisation (normal, subtle or obvious) proposed by mcclure et al. (2009) and applied a dichotomised (e.g. absent or present) category instead using normal (normal + subtle dyskinesis) or obvious categories and achieved a greater k value (0.67 to 0.84) than in our study. this has also been argued elsewhere to be a more suitable method to use for research and clinical use. [21] combined patterns of dyskinesis exist due to patients’ adaptations, which adds to the complexity of the observation of dyskinesis. [22] the reliability of other research is not being compared to this study due the different system used. however, it is worth acknowledging that completing fewer than 10 arm elevations/ lowering cycles may be insufficient to elicit a predominant patterns which may have been unclear with the three repetitions used in other research and for that reason might have influenced results in our study which used five repetitions as outlined in the methods from mcclure et al. (2009). the importance of being able to reproduce the conditions that impose an increased demand to the shoulder resulting in dysfunctional movement patterns highlighted in the aforementioned elite handball study. [19] they used a heavier weight dumbbell for male athletes (3kgs) than described by mcclure et al. (2009). it was concluded that the choice of the heavier dumbbell may have influenced the greater k value (0.67 to 0.84) than those found in the original study (k= 0.55 to 0.58) [11] and similarly in our study. it is therefore plausible to recommend that the imposed stress needs to be sufficiently challenging to provoke a movement impairment while taking into consideration the individual’s strength level and sport demand. test-retest reliability performed one week apart showed similar fair to moderate reliability (mean range 0.22 – 0.44) as found by other investigators [8] for scapular posture. high exact agreement was seen with scapular planes with results exceeding 69% agreement which was also similar to previous findings. [8] a substantial proportion of ratings were different between assessment days, ranging from 0.00 – 1.00 and 33% 100% for the kappa statistic and percentage agreement, respectively. this wide range of intra-rater reliability coefficients highlight the subjective nature and limitations of this type of clinical evaluation. there are two possible reasons for this disagreement from one testing session to the next: it may be due to rater inconsistency, or an actual difference in scapular posture between sessions. potential factors that can be considered to have contributed to the variations in the scapular position at subsequent testing sessions could occur from physical activities conducted in between testing days. [2] due to inconsistent reliability scores for these tests from one day to the next, their practical use in this sporting environment is brought into question. intra-rater reliability of the sdt in this study showed only slight agreement, irrespective of the experience level of the rater. these findings were lower than that found by other investigators sampling inexperienced raters who found substantial to almost perfect agreement in a non-athletic population with shoulder impingement syndrome. [20] the reasons for these findings are not dissimilar to those already discussed for the variability of the inter-rater agreement. in light of these factors, the low level of reliability for the sdt in this small study, does not provide sufficient support for its use in field – based testing conditions irrespective of the level of experience of the rater. this study found paradoxical low kappa values but high exact agreement for inter–rater reliability, similar to other investigations. [17, 19] this was particularly true for the agreement of the scapular in the horizontal (91% 97%) and vertical plane (88% 97%), compared to kappa values of 0.00 and -0.02 to 0.00, respectively. similarly, these findings were evident in the test -retest results in the scapular, vertical and horizontal planes, with kappa values as low as 0.00 while the exact agreement was 100%. these exact agreement values in the horizontal plane are likely due to the position of the medial border of the scapular being more than 5 cmway from the midline and its prominence in the physique of rugby players. similarly, the position of the scapular in the vertical plane is an indication that the players’ scapulae sit in a neutral position in this plane. in a homogeneous sample in which there is little variability, interpreting the results from the kappa statistic may be misleading. the first limitation of this study was that the sample size (n=17) was below the general recommendation for obtaining reasonable precision for estimates of reliability that requires at least 50 participants to be recruited to the study, preventing us from drawing firm conclusions regarding the reliability of the shoulder physical examination used in this study. the students could have spent more time training with these assessment methods and pilot testing. the challenging nature of these assessments, testing condition-imposed time constraints and the difference in professional training of physiotherapists and sport rehabilitation students may have had implications on the findings. conclusion visual inspection of the static scapular posture, clavicular tilt angle and the scapular dyskinesis between students and an expert physiotherapist had low reliability in this small study. these findings highlight the limitation of this type of clinical evaluation by sports rehabilitation students and warrants that clinicians are aware of their variability. both tests require further research to determine their validity and clinical utility. conflict of interest and source of funding: the authors declare no conflict of interest. this work was supported by the private physiotherapy education foundation. acknowledgements: the author would like to express his gratitude to the undergraduate sport rehabilitation students (lee culverhouse, holli finnis, anna raven, jessica stockwell, lewis wentland) at uwe, bristol for their valuable help with the data collection. original research 7 sajsm vol. 33 no. 1 2021 author contributions: all authors were involved in the concept, design, analysis and interpretation of data, drafting of intellectual content and approval of the version to be published. references 1. herrington l, horsley i. electromyographic analysis of selected shoulder muscles during a rugby football tackle. sports med arthrosc ther technol 2009;1(1). 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[doi: 10.1067/mse.2002.126766] [pmid: 12469078] review 1 sajsm vol. 34 no. 1 2022 creative commons attribution 4.0 (cc by 4.0) international license the effectiveness of intratissue percutaneous electrolysis for the treatment of tendinopathy: a systematic review d augustyn,1 dpt, mphyst sports med; a paez,1,2 dpt, msc 1 college of professional studies, northeastern university, 360 huntington ave, boston, ma 02115, usa. 2 nuffield department for primary care health sciences, university of oxford, radcliffe primary care building, woodstock rd, oxford ox2 6gg, uk corresponding author: d augustyn (divanaugustyn@gmail.com) tendinopathy is a chronic overuse injury characterised by tendon degeneration, resulting in pain and decreased activity level. tendinopathy is highly prevalent in the general public and common in athletes, representing up to 50% of all sports injuries.[1] the term ‘tendinopathy’ is generally used to describe tendon disorders that include acute tendonitis, as well as chronic tendinosis. from acute tendinitis to chronic tendinosis, it is important to recognise that each stage of the tendinopathy process involves specific histological changes, and that each stage of the disease has the potential to respond differently to various treatment modalities.[2] tendinitis refers to tendon inflammation and results from microtears that happen when the musculotendinous unit is acutely overloaded with a tensile force that is too heavy for it and/or applied too suddenly. tendinitis lasts up to three weeks.[2] tendinosis is characterised by a chronic evolution of the degenerative process, including the formation of fibrotic tissue, degradation of myxoid substance, and decreased capillary blood flow, resulting in stagnation of the inflammatory cells (neutrophils and macrophages) required for phagocytosis. [2] many treatment techniques, with varying evidence of effectiveness, are currently used to treat tendinopathy including rest, physiotherapy, eccentric exercise,[3] extracorporeal shockwave therapy,[3] non-steroidal antiinflammatory drugs, corticosteroids, and platelet-rich plasma injections.[4] despite this, up to 29% of patients with tendon injuries develop chronic tendinopathy and require surgical management.[5] patients with decreased functional status compared to preinjury level and increased pain before treatment may also be less likely to return to a pretendinopathy functional level.[5] intratissue percutaneous electrolysis (epi) is one modality for the treatment of chronic tendinopathy.[6] various synonymous terms for epi are found in the literature, including ultrasound-guided galvanic electrolysis technique (usget),[7] percutaneous micro electrolysis (mepv),[8] percutaneous needle electrolysis (pne),[9] and ultrasoundguided percutaneous electrolysis.[10] intratissue percutaneous electrolysis is an ultrasound-guided physiotherapeutic technique in which electrical stimulation is applied to the injured tendon via an acupuncture needle to produce localised inflammation at the treatment area and stimulate tendon healing .[6] intratissue percutaneous electrolysis utilises a combination of mechanical (needle) and electrical (galvanic current) stimulation to provide controlled micro-trauma and non-thermal electrochemical ablation directly to the area of the degenerated tendon. this leads to the production of sodium hydroxide molecules, altered ph and increased oxygen in the treatment site, enabling cellular phagocytosis, and activating tendon repair.[6,7] little consensus exists for epi’s efficacy or the most effective treatment protocol. to the best of our knowledge, no systematic review of epi treatment had been published at the time this systematic review was undertaken. a systematic review of epi is needed to critically appraise the evidence for its effectiveness and provide recommendations for clinicians background: tendinopathy is highly prevalent in the general public and common in athletes. it makes up nearly 50% of all sport injuries. a number of treatment techniques with varying evidence of effectiveness are currently available. intratissue percutaneous electrolysis (epi) is one such modality, however little consensus exists for epi’s efficacy or the most effective treatment parameters. objective: to review and appraise available evidence for intratissue percutaneous electrolysis (epi) in the treatment of tendinopathy, examining the effectiveness of epi in conjunction with other modalities and identifying the strengths and limitations of the evidence base for epi in order to make evidence-based recommendation for future studies of epi. methods: pubmed, embase and scopus were searched with keywords related to epi and tendinopathy. grey literature searches were conducted with embase, opengrey, and proquest. extensive citation searching was undertaken. randomised controlled trials (rcts), uncontrolled and observational studies of the application of epi in patients aged 18-65 years with magnetic resonance imaging (mri) or clinical ultrasonography (us) confirmed diagnosis of tendinopathy were eligible. results: eleven studies met inclusion criteria: six randomised control trials (rcts) and five uncontrolled studies. clinical trials of epi as an adjunct modality with physical therapy reporting greater decreased pain and return to function than treatment with physical therapy alone. the evidence for epi is limited and influenced by small sample sizes, varying treatment protocols, clinical heterogeneity and high risk of bias. conclusion: it is currently not possible to conclude that epi is an effective modality for the treatment of tendinopathy. rcts with clearly described epi treatment protocols, larger sample sizes and intervention reporting sufficient to support reproducibility are needed to determine the effectiveness of epi for the treatment of tendinopathy. keywords: tendinosis, intratissue percutaneous electrolysis, percutaneous electrolysis s afr j sports med 2022;34:1-8. doi: 10.17159/2078-516x/2022/v34i1a12754 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a12754 https://orcid.org/0000-0003-1675-0335 https://orcid.org/0000-0002-7984-514x review sajsm vol. 34 no. 1 2022 2 and future research on its use in the treatment of tendinopathy. the primary objective of this review is to examine, categorise and critically appraise available evidence for epi in the treatment of tendinopathy to determine if epi is a safe and effective treatment for tendinopathy, identifying the strengths and limitations of the current body of evidence and making evidence-based recommendations for future research. methods this systematic review was undertaken with the guidance of the cochrane handbook for systematic reviews of interventions, the centers for review and dissemination (crd), the university of york guide, and reported according to the recommendations of the preferred reporting items for systematic reviews and meta-analyses (prisma) statement.[11] the review protocol was registered on prospero: http://www.crd.york.ac.uk/prospero/display_record.php?i d=crd42018118345 information sources keywords and medical subject headings (mesh) related to tendinopathy, tendinosis, intratissue percutaneous electrolysis, and percutaneous electrolysis were used in searches across multiple search engines and databases. no publication date or language limits were imposed. searches were undertaken on pubmed, cinahl, embase, scopus, and the cochrane library. the prospero was searched for ongoing or recently completed systematic reviews addressing the review questions. to include epubs available ahead of the full publication, pubmed and embase were searched again with the same methods, limiting results to articles added within the previous 90 days. extensive searches in embase, opengrey, scopus, and proquest-digital dissertations were conducted for grey literature, including academic and conference papers. to ensure literature saturation, the reference lists of relevant papers were also searched, and citation searches were run on scopus and pubmed. inclusion criteria randomised controlled trials, uncontrolled and observational studies of the application of epi in patients aged 18-65 years with clinical ultrasonography (us) or magnetic resonance imaging (mri) confirming diagnosis of tendinopathy were eligible. patients included in these studies had to have tendinopathy symptoms present for more than three weeks, the time frame where post-inflammatory (tendinitis) degeneration is present.[1] exclusion criteria single subject case studies, case series, and animal studies were excluded. studies with patients with bilateral symptoms, or who had undergone prior surgery for tendinopathy or received corticosteroid injections or used non-steroidal antiinflammatory drugs during treatment were excluded. studies of epi not used in tendons were ineligible. study selection search results were organised and collated into an electronic bibliographic database using refworks citation manager. duplicate articles were identified and removed before proceeding with the screening process. eligibility assessment was performed independently by two reviewers. papers were initially screened against the review’s inclusion and exclusion criteria by title and abstract, then by full-text if eligible. a fulltext review was also performed when eligibility was unclear by title or abstract. when necessary, study authors were contacted for additional information to resolve questions about their study’s eligibility. data synthesis a custom excel spreadsheet was developed to collect data about and summarise included articles and to quantify extracted information. information related to study design, sample characteristics, epi methods, and outcome measures was extracted into the spreadsheet. simple, descriptive statistics were used to quantify the results of the literature searches, screening, and systematic reviews. risk of bias and quality assessment to assess the methodological quality of the included articles, two different checklists were used. for the articles related to descriptive epidemiology and aetiology, the quality in prognosis studies (quips) tool was used (appendix 1). the cochrane collaboration’s tool was used for the articles related to prevention (appendix 1). for both the quips and the cochrane collaboration’s tool, six potential bias domains were assessed with a high, moderate or low risk of bias. for assessments using the quips tool, a study was considered to have a low risk of bias rated as low or moderate in all six domains, with at least four domains being rated as low.[12] if two or more domains were scored as high, the study was rated as having a high risk of bias.[12] studies that were in between were scored as having a moderate risk of bias.[13] for assessments using the cochrane collaboration tool, a study was assessed with a low risk of bias when all items were assessed as low.[13] when at least one item was assessed as moderate, the article received a score with a moderate risk of bias. a high risk of bias was rated when at least one item was assessed as high.[13] the checklists were assessed and crosschecked by two researchers (da and ap). if a difference of opinion arose concerning the scoring of an item, a consensus was reached. the cochrane risk of bias (rob) tool[12] was used for randomised controlled trials. the rob is widely available, and its reliability and validity have been shown previously.[13] the cochrane rob was chosen based on the authors’ experience and prior training with the rob and following the recommendations of the cochrane collaboration guide to systematic reviews. the rob focuses on different aspects of trial design, conduct, and reporting across seven domains of bias (table 6). a series of signalling questions within each domain elicits information about the features of a trial relevant to the risk of bias. an algorithm is used to generate a judgement about the risk of bias for each domain based on the http://www.crd.york.ac.uk/prospero/display_record.php?id=crd42018118345 http://www.crd.york.ac.uk/prospero/display_record.php?id=crd42018118345 http://www.crd.york.ac.uk/prospero/display_record.php?id=crd42018118345 review 3 sajsm vol. 34 no. 1 2022 answers to the signalling questions. judgements can be classified as ’low’ risk of bias, ’some concerns’ or ’high’ risk of bias. [12,13] the framework for assessing the internal validity of prognostic studies developed by altman (table 1), posing key questions about study quality and the trustworthiness of studies’ results was used to assess the quality of all other study types.[14] results fifty-five papers were found: 48 in pre-specified search engines and seven from citation and bibliographic searching (figure 1). after duplicates and ineligible papers were removed, 17 papers were screened and assessed against inclusion and exclusion criteria. eleven papers met full eligibility criteria, including six randomised controlled trials (rct) and five uncontrolled studies (table 2). the results, including effect estimates and 95% confidence intervals of rcts, are presented in table 3, and the results of the uncontrolled studies in table 4. studies’ epi treatment parameters, including intensity, duration, and the number of sessions are presented in table 5. a variety of outcome measures for patient-reported pain levels were used across eligible studies, including the numerical pain rating scale (nprs),[10,11] the numerical rating scale (nrs),[15] the visual analogue scale (vas),[8,9] and the shoulder pain and disability index (spadi).[16] each of these scales is used to rate pain from zero (no pain) to 10 (worst pain). randomised controlled trials (rcts) of the six eligible rcts, three investigated epi treatment of shoulder tendons,[10,16,17] and one each for the knee,[7] ankle,[8] and thigh tendons.[15] primary outcome measures used by two shoulder tendon studies was the vas,[10,17] the third used the dash questionnaire.[16] the knee tendon study utilised the visa-p scale, the ankle study the visa-a scale, and the thigh study the vas as primary outcome measures. three of the rcts used a treatment intensity between two and six milliampere (ma) with a table 1. quality assessment for assessing internal validity of studies, adapted from altman, 2001 [13] study feature qualities sought* sample of patients were the inclusion criteria defined? were sample characteristics described? was sample selection explained? did recruitment take place at the common stage or defined period? was the sample representative of the population it is drawn from? follow-up of patients was follow-up long enough for the clinical outcomes (5 years)? was follow-up complete (80%)? outcome assessment was it objective or independently adjudicated? was the method standardized with objective tools? was the outcome fully defined? *low risk of bias: meets all or most of the criteria for a study feature; or high risk of bias: meets less than half of the criteria for a study feature fig. 1. prisma flow diagram in c lu d e d e li g ib il it y id e n ti fi c a ti o n s c re e n in g 48 records identified through database searching (15 pubmed, 15 embase, 6 cinhal, 12 scopus) 7 additional records identified through other sources: (bibliographic/citation searching, scopus, embase hand-searching) 55 records screened for duplicates 16 duplicates removed 39 titles and abstracts screened 22 records excluded (not relevant to review) 2 full-text articles excluded, did not address review outcome: 1 did not meet eligibility criteria: 1 4 uncontrolled studies excluded did not meet eligibility criteria: 4 17 full-text articles assessed for eligibility 11 studies included in quantitative synthesis (meta-analysis) 6 randomised controlled trials, 5 uncontrolled studies. 11 studies eligible 6 randomised controlled trials, 5 uncontrolled studies. review sajsm vol. 34 no. 1 2022 4 maximum of five seconds active epi up to three times per session ;[7,15,17] however, abat et al.[7] applied epi to the area until complete debridement without time specification. the three remaining rcts used intensities between 100 and 450 microamperes (a) with a treatment duration up to 90 seconds.[8,10,16] the characteristics of each study, as well as primary outcome measures, are listed in table 2. results are presented in table 3, and the treatment protocols in table 5. quality assessment results are presented in table 6. uncontrolled studies five prospective, uncontrolled studies were eligible for inclusion.[6,9,18,19,20] three investigated epi treatment in patellar tendon tendinopathy using the visa-p scale as the primary outcome measure.[6,18,19] one study had a 10-year follow up (88% completion rate),[6] one a two year follow up[19] and one a six week follow up (both 100% completion rate).[18] two studies investigated lateral epicondylitis of the elbow and used the vas and the dash questionnaire as primary outcome measures,[9,20] with 6 week follow-up periods (100% completion rate). all uncontrolled studies utilized a treatment intensity of three to six milli ampere, three studies utilized a duration of three to five seconds performed three times,[9,18,20] while two studies applied epi until the area was debrided.[6,19] the characteristics of each study as well as primary outcome measures are listed in table 2. results are presented in table 4, and treatment protocols are listed in table 5. quality assessment was performed using altman criteria in table 1. table 2. characteristics of studies included study and type joint population size intervention and exposure outcome measure arias-buria et al., 2015[10] randomised controlled trial shoulder epi group (n=17) exercise group (n=19) 1 session epi per week for 4 weeks applied to supraspinatus tendon and eccentric exercise similar eccentric exercise as epi group vas* dash † valtiera et al., 2018[16] randomised controlled trial shoulder control group (n=25) epi group (n=25) manual therapy for 5 sessions and exercise x2 per day for 5 weeks manual therapy and exercise as control, and epi with every manual therapy session dash*, spadi †, groc† moreno md, 2015[17] randomised controlled trial shoulder control group (n=10) epi muscle group 1 (n=10) epi tendon group (n=10) epi muscle and tendon group (n=10) continue daily activities epi applied to trigger points in the muscle belly epi applied only to the tendon of the infraspinatus epi applied in trigger points and tendon vas* abat et al., 2016[7] randomised controlled trial knee control group (n=30) epi group (n=30) 50 minutes of ept 3x/week for 8 weeks and eccentric exercise 1 epi session every 2 weeks and similar eccentric exercise as a control visa-p * ronzio et al., 2017[8] randomised controlled trial ankle control group (n=10) epi group (n=10) friction massage of achilles and eccentric exercise of the plantar flexors same treatment as group 1 as well as epi visa-a* vas* moreno et al., 2017[15] randomised controlled trial thigh epi group (n=11) control group (n=13) epi and apt program apt program vas* psfs† valera garrido et al., 2010[18] uncontrolled study knee 32 patients observational study one session epi as well as eccentric training program per week for 4-6 weeks visa-p* valera garrido et al., 2014[9] uncontrolled study elbow 36 patients one session epi per week 4-6 weeks as well as a home eccentric exercise program and stretching dash* ultrasound image changes† abat et al., 2014[19] uncontrolled study knee 33 patients studied prospectively 1 session of epi treatment (average of 4,5 sessions per patient) per week and 2 eccentric exercise sessions per week visa-p* abat et al., 2015[6] uncontrolled study knee 40 patients studied prospectively epi treatment up to a maximum of 10 sessions or until symptom-free in conjunction with eccentric exercise program visa-p* munoz et al., 2012[20] uncontrolled study elbow 36 patients – cost effectiveness study one session epi, eccentric exercise program and stretching per week for 4-5 weeks vas* dash* * indicates primary outcome measure; † indicates secondary outcome measure. epi, intratissue percutaneous electrolysis; vas, visual analogue scale; dash, disabilities of the arm, shoulder and hand; spadi, shoulder pain and disability index; groc, global rating of change; ept, electrophysiotherapeutic treatment; visa-p, victorian institute of sport assessment – patella; visa-a, victorian institute of sport assessment – achilles; apt, active physical therapy; psfs, patient-specific functional scale. review 5 sajsm vol. 34 no. 1 2022 quality assessment quality assessment of rcts with the cochrane rob (table 6) and other studies with altman’s criteria (table 1) resulted in a high risk of bias in all of the rcts and uncontrolled studies eligible for inclusion in this systematic review. the greatest risk of bias among rcts was found in the blinding of outcome assessment and selective reporting. among uncontrolled studies, risk of bias was found in all studies, ranging low[9] to high risk.[6,18,19,20] table 3. results of randomised controlled trials study group population characteristics* measure instrument effect estimate and 95%ci† arias-buria et al., 2015[10] epi exercise 4/13, 58  7 5/14, 57  6 vas dash vas dash -5.6(-6.4, -4.7) ‡ -46.3(-52.2, -40,5) ‡ -3.7(-4.6, -2.9) -36.8(-42.2, -31.4) valtiera et al., 2018[16] control epi 12/13, 55.3  11.1 11/14, 54.9  13.7 dash vas spadi dash vas spadi 4.1  3.4 (3.1, 5.1) 27.6  17.1 (22.7, 32.5) -9.9 (-20, -0.3) § 1.5  1.8 (2.3, 3.3) 10.1  6.5 (4.7, 15.5) moreno md., 2015[17] control epi muscle epi tendon epi muscle and tendon --,39.6  3.69 --, 40.4  3.20 --, 39.9  4.15 --, 39.8  4.66 vas vas vas vas -(-4.9, 1.9) -(1.7, 24.3) -(54.6, 66.4) -(66.9, 74.1) abat et al., 2016[7] control epi 24/8, 30.9  5.9 27/5, 31.2  6.5 visa-p <90 (n=19) visa-p >90 (n=11) visa-p <90 (n=8) visa-p >90 (n=22) 61.9  13.7 (55.3-68.5) 95.2  2.5 (93.5-96.9) 63.3  14.3 (51.3-75.2) 97.1  1.7 (96.3-97.8) ronzio et al., 2017[8] physiotherapy epi - - visa-a, vas no values provided moreno et al., 2017[15] epi control 11/0, 26.9  4.5 13/0, 25.2  4.9 vas on palpation vas on contraction psfs vas on palpation vas on contraction psfs 1.1  0.9 (--) 0.5  0.7 (--) 95.4  4.1 (--) 2.0  1.5 (--) 1.6  1.3 (--) 89.9  6.8 * population characteristics values are: male/female, mean age in years  sd; † values are mean sd (95% confidence interval). ‡ denotes change from baseline value. § indicates difference between groups; -indicates no values provided. epi, intratissue percutaneous electrolysis; vas, visual analogue scale; dash, disabilities of the arm, shoulder and hand; spadi, shoulder pain and disability index; visa-p, victorian institute of sport assessment – patella; visa-a, victorian institute of sport assessment – achilles; psfs, patient-specific functional scale. table 4. results of uncontrolled studies study group population characteristics* measure instrument effect estimates (mean ± sd) baseline final follow-up valera-garrido et al., 2010[18] group 1 (n=13) group 2 (n=19) 19/13, 35  8.0 visa-p <50 visa-p >50 33  8 66  7 69  7 88  7 (6 weeks, n=32) valera-garrido et al., 2014[9] n=36 19/17, 38  6.4 vas dash 60.2  8.0 63.6  9 6.0  12.0 13.6  4.1 (6 weeks) abat et al., 2014[19] n=33 group 1† group 2† 29/4, 25.3 (16-53) visa-p <50 visa-p >50 31.5  10.9 68.7  10.3 81.8  14.5 89.4  7.6 (2 years, n=33) abat et al., 2015[6] group 1 (n=21) group 2 (n=19) 17/4, 26  8.49 18/1, 25.7  8.12 visa-p <50 visa-p >50 88.8  10.1 96.0  4.3 (10 years, n=34) munoz et al., 2012[20] n=36 19/17, 38  6.4 vas dash - 37.4 (--) - 63.4  9 * population characteristics values are: male/female, mean age in years  sd; † n values per group unknown; -indicates no values provided. vas, visual analogue scale; dash, disabilities of the arm, shoulder and hand; visa-p, victorian institute of sport assessment – patella; visa-a, victorian institute of sport assessment – achilles. review sajsm vol. 34 no. 1 2022 6 discussion intratissue percutaneous electrolysis (epi) is an innovative treatment technique for a musculoskeletal condition affecting a large portion of the general population. results from this systematic review indicate that epi shows promise as an adjunct modality in the treatment of tendinopathy when combined with exercise or manual therapy, but insufficient quality evidence is currently available to determine whether epi is an effective treatment for tendinopathy. relatively small sample sizes, heterogenic epi treatment parameters and comparator interventions, and a high risk of bias found across available studies makes it difficult to reach definitive conclusions about epi’s effectiveness. the scope and quality of evidence for epi are limited. no rcts were found investigating epi in comparison to a placebo adjunct modality or placebo intervention. thus it is not currently possible to differentiate between the placebo benefit of a modality added to other interventions, such as exercise or manual therapy, and the true effects of epi. additionally, almost half (five of 11) of eligible studies were uncontrolled clinical trials, which can offer preliminary evidence of safety and indicate if there may be a clinical effect worth investigating further but cannot offer evidence of efficacy.[21] the demonstration of a treatment’s efficacy requires a comparison of the response in the treated group with that of a control group receiving a placebo or another active treatment.[21] patients reported a return to function and table 5. treatment protocol used for randomized controlled trials and uncontrolled studies study joint needle intensity duration arias-buria et al., 2015[10] randomised controlled trial shoulder 0.3x25mm, 350a modified according to patient 90 seconds valtiera et al., 2018[15] randomised controlled trial shoulder 0.3x25mm, 350a 90 seconds moreno 2015[17] randomised controlled trial shoulder on depth estimation, specifics not given 6ma 3 doses of 4 seconds abat et al., 2016[7] randomised controlled trial knee not documented 2ma at three locations in tendon until area debrided ronzio et al., 2017[8] randomised controlled trial ankle 0.22x13mm 100a -450a current density of 5.86ma/cm2 3 doses per session 20 seconds epi, rest 40 seconds (total 3min) moreno et al., 2017[15] randomised controlled trial thigh 0.33x50mm 3ma 3 doses of 5 seconds each valera-garrido et al., 2010[18] uncontrolled study knee not documented 4-6ma 3 doses of 3 seconds valera-garrido et al., 2014[9] uncontrolled study elbow 0.3x25mm 4-6ma approximately 3 doses of 3 seconds abat et al., 2014[19] uncontrolled study knee 0.3x0.32mm 3ma until debrided abat et al., 2015[6] uncontrolled study knee 0.3xlength required 3ma until debrided munoz et al., 2012[20] uncontolled/cost-effective study elbow not documented 4-6ma 3 seconds µa, microampere; ma, milliampere table 6. results of cochrane risk-of-bias tool for quality assessment for randomised controlled trials study and level of evidence random sequence generation allocation concealment blinding of participants and personnel blinding of outcome assessment incomplete outcome data selective reporting other bias arias-buria et al., 2015[10] 1b + + ? ? + ? ? valtiera et al., 2018[16] 1b + + + + + ? ? moreno md, 2015[17] 2b + ? abat et al., 2016[7] 1b + + + + ? ronzio et al., 2017[8] 2b ? ? moreno et al., 2017[15] 2b + + + + indicates low risk of bias; indicates high risk of bias; ? indicates medium risk of bias. review 7 sajsm vol. 34 no. 1 2022 reduced pain in four uncontrolled studies of epi together with eccentric exercises, though it is impossible to attribute this to epi in these studies as there were no comparison groups.[6,9,17,18] there were no adverse events reported with epi treatment in the five uncontrolled studies during treatment or at follow-up; however, indicating that epi may be a safe procedure in the treatment of tendinopathy. the high risk of bias found across all eligible studies may have been influenced by heterogenic treatment dosages, participant characteristics and outcome measures, and incomplete reporting of intervention details. a variety of treatment dosages were identified in the review, with epi treatment intensity variously reported in milliamperes (ma) and microamperes (µa). the most consistent epi treatment dosage reported was four-six ma for three sets of three seconds, though other dosages included 350 µa or two ma.[9,18,20] treatment duration lasting between four and 90 seconds in two studies,[10,16] and three other studies describe treatment until the area was “fully debrided,” but how that was characterised or measured was not specified.[6,7,19] intratissue percutaneous electrolysis treatment was investigated as an added modality with various interventions among eligible studies, ranging from epi and eccentric exercise,[8,10] active physical therapy,[15] manual therapy,[20] electrophysiotherapeutic treatment,[7] and general exercises,[16] though these were often not reported sufficiently for reproducibility. control interventions, or cointerventions within the epi group, were not well described across eligible studies. cointerventions in both the epi and control groups may have influenced treatment outcomes separately from epi tendon treatment. for example, moreno[16] investigated standalone epi treatment of adductor tendons in a study of four groups of 10 patients each but does not report if any other treatment was received in addition to epi, and the treatment protocol was not described in detail. greater decreased pain was reported by the epi group than the control groups in both the tendon and a muscular trigger point, though the study investigated the effect of epi on tendinopathy, rather than trigger points. differences in the reporting of results and outcome measures used also make an assessment of epi effectiveness difficult. three rcts presented results supported only by pvalues, without reporting confidence intervals.[8,17] one rct presented results based on visa-p scores categorically as greater or lesser than 90 at follow-up,[7] greatly reducing reported details of epi treatment effects. one rct utilised a goniometric range of motion values at the shoulder as outcome measures without describing the measuring procedure, its validation, or reliability, raising the risk bias in the study,[17] and only three studies assessed epi in the same joint, further limiting the generalisability of the available evidence.[10,16,17] an uncontrolled study comparing epi to surgery focused outcomes on estimated cost, making direct comparison of treatment effects among both interventions difficult.[20] notably, none of the current studies investigated epi for the treatment of tendonitis in the elbow, despite its high prevalence in the general population. all of these factors may also have influenced the inconsistent findings reported among eligible studies. one rct found improved outcomes in both the epi and control groups,[7] while some studies only reported improved outcomes in the epi groups.[8,12,15,17] one study found small improvements in pain but not in function for the epi group,[17] and one study found no differences between the groups.[16] epi is a complex intervention, with a number of independent and interdependent factors potentially influencing the effects of epi treatment. these may include not only epi dosage but also interventionist experience or a learning curve with epi, patient and practitioners’ perception of equipoise and characteristics. differences in practitioners’ skill with epi and their interand intrapractitioner reliability, may also influence the outcome of epi treatment and need to be established and further explored in future research. future studies of epi may benefit from the guidance of frameworks such as ideal-physio or ideal,[21] which is an established framework for guiding evidence-gathering in complex, practitioner-based interventions like epi. the ideal framework prioritises transparent reporting of intervention details and delivery, consideration of pratitioner learning curves or skill with the intervention, standardisation of patient outcomes, and the selection of appropriate study designs for the level of development of innovative complex interventions like epi.[21] conclusion clinical trials investigating epi as an adjunct modality with physical therapy report greater decreased pain and return to function than treatment with physical therapy alone, but the evidence for epi treatment is limited and influenced by clinical heterogeneity, high risk of bias and small sample sizes. therefore, it is not possible to definitely conclude that epi is an effective modality for the treatment of tendinopathy. randomised controlled studies with clearly defined and described protocols for epi treatment, larger sample sizes, better defined control interventions, and reporting sufficient to support reproducibility are needed to determine the effectiveness of epi as an adjunct modality in the treatment of tendinopathy. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: da conceived the systematic review. da and ap prepared and registered the protocol, conducted literature search, eligibility screening, analysis, interpretation, figures, writing and revisions. references 1. hopkins c, fu sc, chua e, et al. critical review on the socioeconomic impact of tendinopathy. asia pac j sports med arthrosc rehabil technol 2016; 4:9-20. 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[doi: 10.1093/ptj/pzx103] [pmid:29077915 doi:%2010.1177/0363546508326983 http://dx.doi.org/10.1097/jsm.0b013e31821d0f65 https://doi.org/10.1007/s00113-017-0310-9 https://doi.org/10.1007/s00113-017-0310-9 https://doi.org/10.1007/s00167-014-2855-2 https://doi.org/10.1186/s40634-016-0070-4 doi:%2010.1080/21679169.2017.1381321 doi:%2010.1080/21679169.2017.1381321 https://doi.org/10.1136/acupmed-2014-010619 https://doi.org/10.1136/acupmed-2014-010619 https://doi.org/10.1155/2015/315219 doi:%2010.1371/journal.pmed.1000097 doi:%2010.1371/journal.pmed.1000097 doi:%2010.1136/bmj.d5928 https://doi.org/10.1136/bmj.323.7306.224 https://doi.org/10.23736/s0022-4707.16.06466-5 https://doi.org/10.1016/j.jpain.2018.04.017 https://doi.org/10.1093/ptj/pzx103 sajsm 595 (commentarty).indd commentary 61 sajsm vol. 28 no. 2 2016 post-concussion return to boxing protocol n k sethi, md department of neurology, new york presbyterian hospital, weill cornell medical center, new york, usa corresponding author: n k sethi (sethinitinmd@hotmail.com) concussion can be defined as a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces [1]. concussion typically involves temporary impairment of neurological function with full recovery over a course of time. currently there are no sensitive or specific biofluid (blood or cerebrospinal fluid) or imaging markers to identify and grade a concussion. in the absence of a valid and reliable biomarker of concussion, current emphasis is on early and accurate identification of the concussion, pulling the player out and advising cognitive and physical rest till symptoms abate. a systematic review of prognosis and return to play after sport concussion found no evidence on the effect of return-to-play guidelines on prognosis. the authors highlighted the need for well designed, confirmatory studies to better understand the consequences of sport concussion across different athletic populations and sports [2]. defining a concussion in boxing boxing is a unique contact sport in that every punch thrown at the head is thrown with the intention of causing a knockout (ko). no single definition of concussion is likely to be universally accepted in boxing and identifying mild grades of concussion (subconcussive blows) during the course of a boxing match is particularly challenging. to help identify and manage a concussion in boxing the following recommendations are proposed based on evidence from other sports and clinical acumen: 1. a knock-down caused by punch to the head should raise concern for a concussion even if the boxer gets back to his feet before the count of 10. 2. if a boxer is knocked down by a punch to the head and is unable to get up within the count of 10 (knockout), he should be automatically determined to have suffered a concussion and treated as such. 3. a boxer who suffers a technical knockout (tko) on account of multiple head shots, should be assessed for concussion at the ringside and in the locker room. 4. a boxer who suffers multiple head shots during the course of the bout should be watched closely during the fight, assessed for concussion inbetween the rounds and after the fight is over. 5. a boxer who is determined to have suffered a concussion should not be allowed to box if he is symptomatic. symptoms of concussion are varied and include a complaint of headache, nausea, double or blurred vision, disorientation and confusion, post-traumatic amnesia for events surrounding the fight, such as the name of the venue, name of the opponent, round in which ko or tko occurred, impaired coordination, balance or gait [3]. such a boxer should be assessed at the ringside or in the locker room for concussion with the aid of standardised tests such as standardized assessment of concussion (sac) test, balance error scoring system (bess) and the king-devick test [4, 5, 6]. such multimodal assessment for concussion improves diagnostic accuracy. 6. a boxer who is determined to have suffered a concussion should be closely watched in the locker room for any signs of neurological deterioration. the decision to transport the boxer to the nearest level i trauma centre for evaluation (diagnostic imaging to rule out intracranial haemorrhage) should be made on a caseby-case basis. 7. mandatory 90 day medical suspension should be issued at the venue for a ko caused by a head blow. this boxer then enters the post-concussion return to boxing protocol. for a technical knockout (tko) caused by head and body blows, period of background: concussion is a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces. immediately following a concussion, an athlete is usually advised physical and cognitive rest until post-concussion symptoms abate. the athlete then enters a stepwise return-to-play protocol. premature return to play risks a second concussion, second impact syndrome, exacerbation and persistence of post-concussive symptoms. various sports governing organisations such as the national football league have developed postconcussion return to play protocols. discussion: professional boxing is a popular contact sport in which concussions are common. professional boxing currently lacks a standardised post-concussion return to boxing protocol. professional boxers are arbitrarily suspended for periods ranging from 30 to 90 days after suffering a technical knockout (tko) due to multiple head and body shots or after a knockout (ko). for some boxers a neurology clearance is requested prior to their return to boxing. conclusion: developing and implementing a postconcussion return to the boxing protocol will standardise a return to boxing decision-making process and help to protect a boxer’s health. this paper proposes a postconcussion return to boxing protocol with the recommendation that the proposed protocol be debated vigorously by the scientific community and evidence-based guidelines be developed by the medical community in conjunction with the professional boxing governing bodies. keywords: boxing, safety, concussion, return-to-play s afr j sports med 2016;28(2):61-62.doi: 10.17159/2078-516x/2016/v28i2a464 http://dx.doi.org/10.17159/2078-516x/2016/v28i2a464 commentary sajsm vol. 28 no. 2 2016 62 suspension ranges from 30 to 45 days. if the boxer, after evaluation by the ringside physician, is deemed to have suffered a concussion, the period of suspension may be longer on the discretion of the ringside physician. the boxer then enters the post-concussion return to boxing protocol. 8. a boxer who is determined to have suffered a concussion should be debarred from sparring or boxing until he is symptomatically back to baseline. he/she is instructed to see a physician (either a commission-appointed physician or an independent unaffiliated physician licensed in the state/country of residence of the boxer) within 24 hours of sustaining a concussion. the onus of enforcing this shall rest with the boxer, his/her corner and promoter. the following post-concussion return to boxing protocol is proposed based on evidence from other sports and clinical acumen: once the boxer is symptom free for at least 24 hours and a release has been signed by the treating physician, he/she can begin a graded return to boxing as detailed below. day 1: light aerobic activity (walking or stationary bike for 10 minutes, no resistance training) day 2: sport-specific activity (jumping rope, shadow boxing) day 3: non-contact training drills (skill drills-pad work, speed bag, heavy bag) day 4: full-contact practice (sparring with head gear) day 5: return to boxing (return to competitive boxing occurs when the period of mandatory medical suspension has expired) each of the above steps should take 24 hours so that a boxer would take approximately one week to progress through the full post-concussion protocol once they are asymptomatic at rest. if any postconcussion symptoms occur while in the stepwise return to boxing programme, then the boxer should be instructed to return to the previous asymptomatic level and try to progress again after a further 24-hour period of rest has passed. as good practice guidelines, the following are further suggested: 1. the referee and ringside physicians should be skilled in identifying concussions in the ring and in the management of a concussed boxer. 2. establishing a database which tracks the number of concussions sustained by professional boxers. the goal of the database shall be to accurately record and report concussions sustained by an individual boxer, track the natural history of concussions and it is hoped this will be a valuable tool in the future for research on concussion risks, treatment and management. the goal and dream in the future is to have an online centralised concussion database for all professional boxers. 3. every professional boxer should have a formal neuropsychological (neurocognitive) evaluation at the time of starting his professional career. this shall act as the baseline. the boxer should undergo a postinjury impact test to document that neurocognitive function is back at baseline before clearance to return to competitive boxing (7). 4. baseline neurocognitive evaluation should be repeated every two years. a decline in neurocognitive function should raise concern and be further assessed on a caseby-case basis. 5. emphasis should be placed on educating boxers, trainers and coaches about concussions and the reported link between multiple concussions and chronic traumatic encephalopathy (cte). conclusion it is recommended that the above proposed protocol be debated vigorously by the scientific community and evidencebased guidelines be developed by the medical community in conjunction with professional boxing governing bodies. boxing can be made safer and a standardised return to boxing protocol is very necessary. references 1. sharp dj, jenkins po. concussion is confusing us all. pract neurol 2015; 15(3):172-186. doi: 10.1136/practneurol-2015-001087 2. cancelliere c, hincapié ca, keightley m, et al. systematic review of prognosis and return to play after sport concussion: results of the international collaboration on mild traumatic brain injury prognosis. arch phys med rehabil 2014; 95(3 suppl):s210-229. doi: 10.1016/j.apmr.2013.06.035 3. lei-rivera l, sutera j, galatioto ja, et al. special tools for the assessment of balance and dizziness in individuals with mild traumatic brain injury. neurorehabilitation 2013; 32(3):463-472. doi: 10.3233/nre-130869 4. yengo-kahn am, hale at, zalneraitis bh, et al. the sport concussion assessment tool: a systematic review. neurosurg focus 2016; 40(4):e6. doi: 10.3171/2016.1.focus15611 5. bell dr, guskiewicz km, clark ma, et al. systematic review of the balance error scoring system. sports health 2011; 3(3):287-295. doi: 10.1177/1941738111403122 6. galetta km, barrett j, allen m, et al. the king-devick test as a determinant of head trauma and concussion in boxers and mma fighters. neurology 2011; 76(17):1456-1462. doi: 10.1016/j.jns.2011.07.039 7. seifert t, bernick c, jordan b, et al. determining brain fitness to fight: has the time come? phys sportsmed 2015; 43(4):395-402. doi: 10.1080/00913847.2015.1081551 http://www.ncbi.nlm.nih.gov/pubmed/25977270 http://www.ncbi.nlm.nih.gov/pubmed/24581907 http://www.ncbi.nlm.nih.gov/pubmed/24581907 http://www.ncbi.nlm.nih.gov/pubmed/24581907 http://www.ncbi.nlm.nih.gov/pubmed/24581907 http://www.ncbi.nlm.nih.gov/pubmed/23648601 http://www.ncbi.nlm.nih.gov/pubmed/23648601 http://www.ncbi.nlm.nih.gov/pubmed/23648601 http://www.ncbi.nlm.nih.gov/pubmed/27032923 http://www.ncbi.nlm.nih.gov/pubmed/27032923 http://www.ncbi.nlm.nih.gov/pubmed/23016020 http://www.ncbi.nlm.nih.gov/pubmed/23016020 http://dx.doi.org/10.1177/1941738111403122 http://www.ncbi.nlm.nih.gov/pubmed/21288984 http://www.ncbi.nlm.nih.gov/pubmed/21288984 http://www.ncbi.nlm.nih.gov/pubmed/21288984 http://www.ncbi.nlm.nih.gov/pubmed/26295482 http://www.ncbi.nlm.nih.gov/pubmed/26295482 122 sajsm vol 18 no. 4 2006 introduction glutamine is primarily synthesised and stored in skeletal muscle and the lungs and is the principal metabolic fuel for the small intestine enterocytes, and for lymphocytes, macrophages, and fibroblasts. 16 under conditions of severe stress (such as trauma, burns, surgery or sepsis), 2,13 these rapidly replicating cells exhibit accelerated use of glutamine, 2 which may result in a 35 50% decrease in plasma glutamine concentrations that lasts for several days. 22 similarly, acute, prolonged, exhaustive exercise resulted in a ≈25% decrease in plasma glutamine concentration, which lasted for 6 9 hours after a marathon. 4 reports of decreased plasma glutamine levels in overtrained athletes at rest 23,27 suggest that long-term chronic exercise stress may result in a chronically depressed plasma glutamine concentration. in the absence of exercise, cortisol infusions in humans resulted in decreased circulating glutamine concentration after 8 hours, 13 indicating that increased glucocorticoid levels are an important factor influencing glutamine turnover. considered together, these 4 studies indicate the following: firstly, that exercise stress increases glutamine utilisation rate, secondly that glutamine stores are not readily available during or after exercise, and thirdly that these effects may be mediated by cortisol. much evidence exists for the negative effects of long-duration endurance exercise on both the non-specific and the specific immune system, including decreased lymphocyte proliferative ability, impaired neutrophil function, impaired antibody synthesis and a decreased cd4 + :cd8 + ratio. 17,19,21,29,30 together these results suggest a possible link between decreased availability of glutamine after exercise stress exposure and post-exercise immune suppression. however, this ‘glutamine hypothesis’ has recently been contested. 14,37 the majority of in vitro studies illustrating original research article mountain-bike racing – the influence of prior glycogen reducing exercise and glutamine supplementation on selected stress and immune parameters c smith (phd (physiological sciences)) k h myburgh (phd (physiology)) department of physiological sciences, stellenbosch university, w cape abstract objective. to investigate the effect of pre-exercise glutamine supplementation and the influence of a prior acute bout of glycogen-reducing exercise on the general stress and immune response to acute high-intensity cycling. design. randomised, double-blind, cross-over supplementation study. setting and intervention. subjects performed a series of 4 simulated mountain-bike races lasting ≈60 minutes each on separate days 1 week apart, with/ without prior glycogen-reducing exercise on a known outdoor course with/ without pre-exercise glutamine supplementation. blood samples were collected preand immediately post-exercise after each race. main outcome measures. circulating concentrations of cortisol (cor) and dehydroepiandrosterone-sulphate (dheas) were assessed at all time points, as well as changes in white blood cell (wbc) subpopulation distribution. results. cor was elevated in all groups post-exercise (p < 0.0001), but neither glycogen reduction, nor glutamine supplementation had any effect. dheas increased post-exercise (p < 0.05), with a greater relative increase in glutamine-supplemented subjects (p = 0.07). total wbc and neutrophil counts in all groups were elevated after exercise (both p < 0.0005). glutamine supplementation had no effect on differential wbc counts or distribution, but total wbc (p = 0.06) and monocyte (p < 0.05) counts showed greater increases after glycogen reduction. glutacorrespondence: c smith department of physiological sciences stellenbosch university private bag x1 matieland 7602 tel: 021-808 4388 fax: 021-808 3145 e-mail: csmith@sun.ac.za mine supplementation was associated with greater postexercise decreases in cd4 + count (p = 0.07) and cd4 + : cd8 + ratio (p = 0.01) after glycogen-reducing exercise. conclusions. we conclude that pre-exercise glutamine supplementation may have an anticortisol effect by enhancing the dheas response to exercise stress. the suppressive effect of glutamine supplementation on cd4 + : cd8 + ratio and its positive effect on monocyte count after repeated bouts of exercise warrants further investigation. pg122-128.indd 122 11/23/06 4:08:55 pm sajsm vol 18 no. 4 2006 123 suppressed immune capacity used concentrations of glutamine below 100 μm. 24,26 however, serum glutamine concentration decreases by only ≈10 20% after strenuous exercise, so that post-exercise glutamine levels are usually maintained at a level in excess of 400 μm. 14 furthermore, while oral glutamine supplementation during the last 30 minutes of a 2-hour exercise bout (laboratory-based cycling) attenuated the decrease in plasma glutamine concentration, it had no effect on the exercise-induced decrease in lipopolysaccharide (lps)-induced neutrophil elastase release or pma-stimulated neutrophil oxidative burst capacity. 36 these studies suggest that plasma glutamine concentration is unlikely to play an important role in the maintenance of the immune response to exercise stress. despite the recent contention that glutamine ‘is not the link’ responsible for exercise-induced immune suppression, 14 a gap exists in the literature with regard to the timing of glutamine supplementation. most in vivo studies reporting no effect of glutamine supplementation administered glutamine either post-exercise 25 or during the later stages of exercise, 36 in other words at a time when immune cell function is already compromised. recently, administration of a single dose of glutamine prior to an acute high-intensity exercise bout, was reported to prevent decreases in post-exercise glutamine levels in female runners. 34 it is therefore possible that the timing of glutamine supplementation may be an important factor influencing its effect in vivo. given the reported involvement of cortisol in glutamine metabolism, 13 it is possible that pre-exercise glutamine supplementation may alter the cortisol response to acute exercise. in turn, given the known negative effects of cortisol on inflammation and th1-mediated immune function, 6,8,15 an effect of glutamine on immune function may not be direct, but only discernible in the context of its influence on endocrine parameters. since the cortisol antagonist dehydroepiandrosterone (dhea) is known to have an opposing effect to cortisol on immune function, 7,33 assessment of this parameter in conjunction with cortisol should provide a more complete picture of possible beneficial effects of glutamine supplementation. therefore, the main purpose of this study was to determine the effect of pre-exercise oral glutamine supplementation on: (i) the general endocrine stress response to an acute bout of high-intensity cycling exercise simulating competition; and (ii) changes in immune cell distribution as a result of this exercise. a second purpose was to investigate the response of these parameters for the same simulated competition, but under more extreme conditions, by inducing low glycogen levels with an acute exercise bout 1 day prior to the simulated competition. methods subject recruitment. eight healthy, sub-elite, competitive male off-road cyclists were recruited. prior to this study, all participants had taken part in at least 1 competitive cross-country mountain bike league event during the racing season in which the study took place. smokers, as well as individuals taking daily vitamins or other dietary supplements, were excluded from the study. subjects were instructed to refrain from using any supplements for the duration of the protocol. informed, written consent was obtained from all volunteers before admittance into the study. the study protocol was approved by the stellenbosch university ethics committee. exercise intervention this double-blind, cross-over design study consisted of 4 simulated mountain bike races, each separated by 1 week. the race took place on a known mountain biking route with a total distance of 20 km. due to logistic difficulty, the exact racing times for each participant could not be recorded. however, all races were ≈60 minutes in duration, which is in accordance with race times recorded for actual competitive events on the same route. for each race, subjects were required to arrive at the laboratory fasted at 08h00. a blood sample was collected, after which each subject received 300 ml of either a glutamine drink (low-calorie drink plus 5 g glutamine) or placebo (low-calorie drink only). subjects warmed up doing an easy 10 km road cycle to the race venue, and competed in a simulated race that started 30 minutes after taking the glutamine/placebo drink. (plasma glutamine concentration was previously reported to double within 30 minutes after a supplementation protocol similar to the one used in our study. 3 ) immediately after finishing the race, another blood sample was obtained. for 2 of the 4 races, normal repletion of glycogen stores was achieved by subjects refraining from training or any other form of exercise for at least 24 hours before the race, as well as eating a carbohydrate-rich supper the evening before the race. two hours of cycling exercise at ≈64% vo2max was previously shown to result in an average decrease in muscle glycogen content from 80 to 18 mmol glucose units/ kg muscle wet weight. 11 taking this protocol into account, for the other 2 races, a significant reduction in glycogen levels was induced by a 3-hour late afternoon cycle while drinking water only, followed by a low-carbohydrate supper the evening before the race. although portion size and quantity were not specified, a list of foods from which to choose was supplied for both meal types, and subjects were instructed not to deviate from this. all races were randomised for glutamine/placebo, but not for glycogen depletion/control. this was done to ensure equal relative competitiveness and motivation of all subjects during all races, especially for races 1 day after glycogen-depleting exercise. sample collection blood was obtained by venepuncture of a forearm vein by experienced phlebotomists at all time points. whole blood was collected in bd vacutainers (preanalytical solutions, plymouth, uk). edta-anticoagulated blood samples were collected for total and differential white blood cell (wbc) count and haematocrit determination. lithium heparin-anticoagulated blood samples were collected for determination of t-cell subpopulations. a third blood sample, collected in a sst vacutainer, was allowed to clot at room temperature for pg122-128.indd 123 11/23/06 4:08:55 pm 124 sajsm vol 18 no. 4 2006 10 minutes, centrifuged at 3000 rpm for 10 minutes at 4°c, and frozen at –80°c for subsequent batch analysis of serum cortisol and dhea-sulphate (dheas) concentrations. sample analysis edta-anticoagulated blood samples were kept at room temperature and analysed within 4 hours after collection for total and differential wbc counts, as well as haematocrit, by automated analysis (coulter stks, beckman/coulter, fullerton, calif.). heparinised blood samples were also kept at room temperature and analysed within 4 hours for t-cell subpopulations using standard 3-colour flow cytometry. automated analysers were used for determination of serum cortisol (access b module 81600, beckman/coulter, fullerton, calif.) and dheas (immulite i, diagnostic products corporation, los angeles, calif.) concentrations. statistical analysis all results are presented as means ± standard error of the mean (sem). effects of glutamine supplementation and prior exercise on parameters investigated, were assessed using repeated measures factorial analysis of variance (anova). differences between groups were determined using bonferroni’s post hoc tests. level of significance was set at p < 0.05. results two athletes competed in only 1 race each, after which they withdrew from the study due to injuries unrelated to the study protocol. the data obtained for these 2 subjects were excluded from the analyses illustrated below. all subjects were questioned about episodes of illness in the week prior to each race to prevent illness from confounding results obtained. only 1 subject reported such an episode (sore throat for 2 days which was treated only for symptoms). in this case, the subject was not allowed to take part in the study protocol for a period of 1 week. due to problems not related to the study, 3 other subjects also failed to take part in 1 of the simulated races. therefore, these 4 subjects together took part in a fifth race, 1 week after the last race, to finish the protocol. average age, height and body mass of the participants were 28 ± 5 years, 180 ± 3 cm and 76 ± 7 kg respectively. haematocrit values changed significantly from before to after exercise (0.45 ± 0.003 v. 0.46 ± 0.004, p < 0.01). therefore, all post-exercise values were adjusted according to the percentage change in haematocrit, to correct for changes in plasma volume, prior to statistical analysis. a main effect of racing exercise was an increase in cortisol concentration from baseline (p < 0.0001, fig. 1), which was independent of both glutamine supplementation and prior glycogen-reducing exercise. dheas concentration was also increased as a result of racing exercise (before 10.7 ± 0.9 v. after 14.0 ± 1.1 umol/l, p < 0.05). glutamine supplementation was associated with a tendency for greater relative change in dheas concentration in response to racing exercise, independent of prior glycogen-reducing exercise (p = 0.07, fig. 2). however, the cortisol: dheas ratio was not different between treatment groups (main effect of treatment: p = 0.97). 1 statistical analysis: main effects anova indicated significant effect of exercise (p < 0.0001), but no effect of either glutamine supplementation or glycogen reduction. bonferroni’s post hoc analysis showed no significant difference between groups at any time point. error bars indicate sem. (gs-d = glutamine-supplemented, prior glycogen-reducing exercise; gs-r = glutamine-supplemented, glycogen-replete and rested; ps-d = placebosupplemented, prior glycogen-reducing exercise; ps-r = placebosupplemented, glycogen-replete and rested.) 0 100 200 300 400 500 600 700 800 900 1000 gs-d gs-r ps-d ps-r c o rt is o l (n m o l/ l ) before after b b b b a a a a statistical analysis: main effects anova indicated significant effect of exercise (p < 0.0001), but no effect of either glutamine supplementation or glycogen reduction. bonferroni’s post hoc analysis showed no significant difference between groups at any time point. error bars indicate sem. (gs-d = glutamine-supplemented, prior glycogen-reducing exercise; gs-r = glutamine-supplemented, glycogen-replete and rested; ps-d = placebo-supplemented, prior glycogenreducing exercise; ps-r = placebo-supplemented, glycogen-replete and rested.) fig. 1. the effect of prior glycogen-reducing exercise and glutamine supplementation on the average cortisol response to ≈60 minutes of simulated mountain bike racing. 1 statistical analysis: anova tendency for a main effect of glutamine supplementation on the dheas response to exercise (p = 0.07), but no effect of prior glycogen-reducing exercise. bonferroni’s post hoc analysis: no significant difference between groups. error bars indicate sem. 0 10 20 30 40 50 60 70 glycogen reduced glycogen replete d h e a s (% c h a n g e ) placebo glutamine suppleme nted statistical analysis: anova tendency for a main effect of glutamine supplementation on the dheas response to exercise (p = 0.07), but no effect of prior glycogen-reducing exercise. bonferroni’s post hoc analysis: no significant difference between groups. error bars indicate sem. fig. 2. the effect of glutamine supplementation and prior glycogen-reducing exercise on the relative dheas response to ≈60 minutes of simulated mountain bike racing. nted s pg122-128.indd 124 11/23/06 4:08:56 pm sajsm vol 18 no. 4 2006 125 all wbc counts are summarised in table i. a main effect of racing exercise was a significantly increased overall total wbc count (before 5.38 ± 0.27 v. after 8.87 ± 0.89 x 10 3 cells/ul, p < 0.0005) which was mainly due to a significantly increased neutrophil count (before 2.88 ± 0.23 v. after 6.12 ± 0.81 x 10 3 cells/ul, p < 0.0005), while the changes in monocyte (before 0.51 ± 0.02 v. after 0.59 ± 0.05 x 10 3 cells/ul, p = 0.14) and total lymphocyte (before 1.80 ± 0.12 v. after 2.03 ± 0.18 x 10 3 cells/ul, p = 0.42) counts were not significant. while the racing exercise-induced changes in neutrophil and total lymphocyte counts were independent of both glutamine supplementation and previous glycogen-reducing exercise, there was a main effect of glycogen-reducing exercise on the response of wbc (p = 0.06) and monocytes (p = 0.05) to racing exercise, with greater increases in cell count after glycogen-reduction than in the rested, glycogenreplete state, independent of glutamine supplementation (fig. 3). although the total lymphocyte count did not change significantly as a result of simulated racing exercise, with no apparent effect of either glutamine supplementation or prior glycogen-reducing exercise, a clearer picture is obtained by considering changes in t-lymphocyte subpopulation distribution. racing exercise had a significant main effect on relative cd4 + cell count, which decreased significantly after exercise (before 40.7 ± 1.1 v. after 36.5 ± 1.0%, p < 0.005). furthermore, while the percentage of cd8 + cells relative to the total lymphocyte count was not significantly influenced by racing exercise, glutamine supplementation or prior glycogenreducing exercise (p = 0.11, fig. 4a), there was a tendency for an interaction effect of glutamine supplementation and glycogen reduction on the relative cd4 + cell (p = 0.07, fig. 4b) response to racing exercise. this resulted in a significant interaction effect of glutamine supplementation and glycogen reduction on the cd4 + :cd8 + ratio (p = 0.01, fig. 4c), so that the decrease in cd4 + :cd8 + ratio was significantly greater when glutamine-supplemented when compared to placebo, after glycogen reduction (p < 0.05, fig. 4c), but with no apparent differences when rested and glycogen-replete. however, despite this decrease, average cd4 + :cd8 + ratio remained within the expected range for athletes throughout the protocol (before 1.84 ± 0.12 v. after 1.62 ± 0.09). discussion our results illustrate the following main findings: (i) that in the presence of prior glycogen-reducing exercise glutamine supplementation results in greater increases from baseline in total wbc and monocyte counts after simulated racing exercise; (ii) that glutamine supplementation may play a role in increasing dheas levels in a stress situation irrespective of glycogen availability; and (iii) that glutamine supplementation affects the relative distribution of t-lymphocyte subpopulations in response to exercise under competition conditions with insufficient glycogen availability. mountain biking was recently characterised as an intermittent high-intensity endurance sport, with heart rate during a race ranging from 165 to 205 beats per minute (bpm) (mean of 91% of maximum heart rate previously assessed in a laboratory setting). 32 due to the nature of the terrain there are great fluctuations in power output (range 50 400 w) for male participants in national and international racing events. 32 while running and road cycling require a more or less constant, continuous effort, mountain biking therefore displays a succession of very high and lower power requirements, necessitating bursts of both power and endurance, and therefore both anaerobic and aerobic fitness. in agreement with earlier studies of endurance athletes, 9,10,18 cortisol increased from baseline to post-exercise. however, in addition our results also suggest an indirect anticortisol effect of glutamine, since glutamine-supplemented groups exhibited greater increases in dheas concentrations in response to exercise, compared with placebo groups 1 (a) statistical analysis: main effects anova indicates a tendency for a main effect of prior glycogen-reducing exercise (p = 0.06). bonferroni’s post hoc analysis: no significant difference between groups. error bars are sem. (b) statistical analysis: main effects anova indicates a significant effect of prior glycogen-reducing exercise (p = 0.05). bonferroni’s post hoc analysis: no significant difference between groups. error bars are sem. 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 glycogen reduced glycogen replete w b c c o u n t c h a n g e (c e ll s /u l ) placebo glutamine suppleme nted -200 -100 0 100 200 300 400 glycogen reduced glycogen replete m o n o c y te c o u n t c h a n g e (c e ll s /u l ) placebo glutamine suppleme nted b) statistical analysis: main effects anova indicates a significant effect of prior glycogen-reducing exercise (p = 0.05). bonferroni’s post hoc analysis: no significant difference between groups. error bars are sem. fig. 3. the effects of glutamine supplementation and prior glycogen-reducing exercise on a) total wbc and b) monocyte responses, to ≈60 minutes of simulated mountain bike racing. nted 1 (a) statistical analysis: main effects anova indicates a tendency for a main effect of prior glycogen-reducing exercise (p = 0.06). bonferroni’s post hoc analysis: no significant difference between groups. error bars are sem. (b) statistical analysis: main effects anova indicates a significant effect of prior glycogen-reducing exercise (p = 0.05). bonferroni’s post hoc analysis: no significant difference between groups. error bars are sem. 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 glycogen reduced glycogen replete w b c c o u n t c h a n g e (c e ll s /u l ) placebo glutamine suppleme nted -200 -100 0 100 200 300 400 glycogen reduced glycogen replete m o n o c y te c o u n t c h a n g e (c e ll s /u l ) placebo glutamine suppleme nted 1 (a) statistical analysis: main effects anova indicates a tendency for a main effect of prior glycogen-reducing exercise (p = 0.06). bonferroni’s post hoc analysis: no significant difference between groups. error bars are sem. (b) statistical analysis: main effects anova indicates a significant effect of prior glycogen-reducing exercise (p = 0.05). bonferroni’s post hoc analysis: no significant difference between groups. error bars are sem. 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 glycogen reduced glycogen replete w b c c o u n t c h a n g e (c e ll s /u l ) placebo glutamine suppleme nted -200 -100 0 100 200 300 400 glycogen reduced glycogen replete m o n o c y te c o u n t c h a n g e (c e ll s /u l ) placebo glutamine suppleme nted nted l l a) statistical analysis: main effects anova indicates a tendency for a main effect of prior glycogen-reducing exercise (p = 0.06). bonferroni’s post hoc analysis: no significant difference between groups. error bars are sem. pg122-128.indd 125 11/23/06 4:08:58 pm 126 sajsm vol 18 no. 4 2006 (fig. 2). glutamine is known to play a role in amino acid synthesis, 16 and both glutamine and testosterone were reported to prevent glucocorticoid-induced muscle atrophy in animal and human models. 28 our result suggests that glutamine-enhanced dheas synthesis may be a possible mechanism for this beneficial effect, via an increased capacity for testosterone production. maintenance of dheas levels is also associated with positive outcomes in situations of increased stress, 1,7 while chronic decreased serum dheas concentration is associated with progression of various chronic diseases. 5,12,35,38 it is therefore of importance to investigate this potentially beneficial effect of glutamine more comprehensively in this and other appropriate models of stress. our result of an effect of repeated exercise bouts on total wbc and monocyte count is in partial agreement with the association reported between the magnitude of increase in wbc counts and the severity of stress, 17,20 with the exception that our results do not illustrate an association between neutrophil or total lymphocyte count and glycogen status. also, our results are in agreement with previous studies, that neither total wbc, nor differential wbc counts post-exercise were significantly influenced by glutamine supplementation. 36 however, if glutamine supplementation is not considered as a main effect (groups gs-r and gs-d) but only in the context of the more severe condition of simulated stage racing with insufficient glycogen supplementation, a different conclusion is reached. our results indicate an interaction effect of glutamine and prior glycogen-reducing exercise on t-cell subpopulation distribution, so that the magnitude of exercise-induced decrease in the cd4 + :cd8 + ratio is significantly greater after glutamine supplementation when exercise is started in a state of reduced glycogen availability. a possible explanation is that glutamine indirectly affected the cd4 + :cd8 + ratio by enhancing dheas release. dheas is known to increase interleukin-2 (il-2) secretion, 7 which enhances the th1 response, 31 which includes enhanced differentiation and proliferation of (cd8 + ) cytotoxic and suppressor t-cells to improve cell-mediated immunity. therefore, while glutamine may not have a direct effect on immune cell function, it may be indirectly beneficial to cell-mediated immune function. conclusion the results show that supplementation with glutamine before exercise may have an indirect anticortisol effect by increasing the dheas response to exercise. however, this possible effect requires validation in a larger subject group. in addition, b) statistical analysis: main effects anova showed a main effect of exercise (p < 0.005) and a tendency for an interaction effect of glutamine supplementation and prior glycogen-reducing exercise (p = 0.07), but no effect of glutamine supplementation or prior glycogen-reducing exercise alone. bonferroni’s post hoc analysis showed no difference between groups. error bars indicate sem. a) statistical analysis: main effects anova showed no effect of exercise, glutamine supplementation, prior glycogenreducing exercise or an interaction between two or more predictors. bonferroni’s post hoc analysis showed no difference between groups. error bars indicate sem. 1 (a) statistical analysis: main effects anova showed no effect of exercise, glutamine supplementation, prior glycogen-reducing exercise or an interaction between two or more predictors. bonferroni’s post hoc analysis showed no difference between groups. error bars indicate sem. (b) statistical analysis: main effects anova showed a main effect of exercise (p < 0.005) and a tendency for an interaction effect of glutamine supplementation and prior glycogen-reducing exercise (p=0.07), but no effect of glutamine supplementation or prior glycogen-reducing exercise alone. bonferroni’s post hoc analysis showed no difference between groups. error bars indicate sem. (c) -6 -4 -2 0 2 4 glycogen reduced glycogen replete c h a n g e in re la ti v e (% ) c d 8 c o u n t placebo glutamine suppleme nted -12 -8 -4 0 4 glycogen reduced glycogen replete c h a n g e in re la ti v e (% ) c d 4 c o u n t placebo glutamine suppleme nted nted 1 (a) statistical analysis: main effects anova showed no effect of exercise, glutamine supplementation, prior glycogen-reducing exercise or an interaction between two or more predictors. bonferroni’s post hoc analysis showed no difference between groups. error bars indicate sem. (b) statistical analysis: main effects anova showed a main effect of exercise (p < 0.005) and a tendency for an interaction effect of glutamine supplementation and prior glycogen-reducing exercise (p=0.07), but no effect of glutamine supplementation or prior glycogen-reducing exercise alone. bonferroni’s post hoc analysis showed no difference between groups. error bars indicate sem. (c) -6 -4 -2 0 2 4 glycogen reduced glycogen replete c h a n g e in re la ti v e (% ) c d 8 c o u n t placebo glutamine suppleme nted -12 -8 -4 0 4 glycogen reduced glycogen replete c h a n g e in re la ti v e (% ) c d 4 c o u n t placebo glutamine suppleme nted nted c) statistical analysis: main effects anova showed a significant interaction effect of glutamine supplementation and prior glycogen-reducing exercise (p = 0.01), but no effect of glutamine supplementation or prior glycogenreducing exercise alone. bonferroni’s post hoc analysis showed a significant difference between gs-d and ps-d (*, p < 0.05). error bars indicate sem. fig. 4. interaction effects of glutamine supplementation and prior glycogen-reducing exercise on absolute change in a) relative cd8 + cell count, b) relative cd4 + cell count, and c) cd4 + :cd8 + ratio post-exercise. 1 (c) statistical analysis: main effects anova showed a significant interaction effect of glutamine supplementation and prior glycogen-reducing exercise (p = 0.01), but no effect of glutamine supplementation or prior glycogen-reducing exercise alone. bonferroni’s post hoc analysis showed a significant difference between gs-d and ps-d (*, p < 0.05). error bars indicate sem. -0.8 -0.6 -0.4 -0.2 0.0 0.2 glycogen reduced glycogen replete c h a n g e in c d 4 :c d 8 ra ti o placebo glutamine suppleme nted * nted pg122-128.indd 126 11/23/06 4:09:01 pm sajsm vol 18 no. 4 2006 127 glutamine was associated with a decreased cd4 + :cd8 + ratio in response to exercise in a glycogen-depleted state. acknowledgements the authors would like to thank eas international for the donation of the l-glutamine used as supplement in this study. references 1. araneo ba, shelby j, li gz, ku w, daynes ra. administration of dehydroepiandrosterone to burned mice preserves normal immunologic competence. arch surg 1993; 128: 318-25. 2. biolo g, toigo g, ciocchi b, et al. metabolic response to injury and sepsis: changes in protein metabolism. nutrition 1997; 13: 52-7s. 3. castell lm, newsholme ea. the relation between glutamine and the immunodepression observed in exercise. amino acids 2001; 20: 49-61. 4. castell lm, poortmans jr, newsholme ea. does glutamine have a role in reducing infections in athletes? eur j appl physiol occup physiol 1996; 73: 488-90. 5. cutolo m, foppiani l, prete c, et al. hypothalamic-pituitary-adrenocortical axis function in premenopausal women with rheumatoid arthritis not treated with glucocorticoids. j rheumatol 1999; 26: 282-8. 6. daynes ra, araneo ba, dowell ta, huang k, dudley d. regulation of murine lymphokine production in vivo. iii. the lymphoid tissue microenvironment exerts regulatory influences over t helper cell function. j exp med 1990; 171: 979-96. 7. daynes ra, dudley dj, araneo ba. regulation of murine lymphokine production in vivo. ii. dehydroepiandrosterone is a natural enhancer of interleukin 2 synthesis by helper t cells. eur j immunol 1990; 20: 793-802. 8. deuster pa, zelazowska eb, singh a, sternberg em. expression of lymphocyte subsets after exercise and dexamethasone in high and low stress responders. med sci sports exerc 1999; 31: 1799-1806. 9. gleeson m, bishop nc. elite athlete immunology: importance of nutrition. int j sports med 2000; 21: suppl 1, s44-50. 10. gleeson m, blannin ak, walsh np, bishop nc, clark am. effect of lowand high-carbohydrate diets on the plasma glutamine and circulating leukocyte responses to exercise. int j sport nutr 1998; 8: 49-59. 11. gollnick pd, piehl k, saltin b. selective glycogen depletion pattern in human muscle fibres after exercise of varying intensity and at varying pedalling rates. j physiol 1974; 241: 45-57. 12. grinspoon s, corcoran c, stanley t, rabe j, wilkie s. mechanisms of androgen deficiency in human immunodeficiency virusinfected women with the wasting syndrome. j clin endocrinol metab 2001; 86: 4120-6. 13. hammarqvist f, ejesson b, wernerman j. stress hormones initiate prolonged changes in the muscle amino acid pattern. clin physiol 2001; 21: 44-50. 14. hiscock n, pedersen bk. exercise-induced immunodepression–plasma glutamine is not the link. j appl physiol 2002; 93: 813-22. 15. kunz-ebrecht sr, mohamed-ali v, feldman pj, kirschbaum c, steptoe a. cortisol responses to mild psychological stress are inversely associated with proinflammatory cytokines. brain behav immun 2003; 17: 373-83. table i. absolute total and differential white blood cell counts, as well as absolute and relative lymphocyte subpopulation counts before and after a simulated mountain-bike race (means ± sem) reference range for general population at rest time point gs d gs r ps d ps-r white blood cells 4 000 11 000 cells/ul pre 5 470 ± 530 5 500 ± 600 5 320 ± 530 5 250 ± 640 post 11 610 ± 2 530* 7 600 ± 970 9 320 ± 2 030 6 960 ± 780 neutrophils 2 000 7 500 cells/ul pre 2 920 ± 460 2 950 ± 490 2 800 ± 550 2 860 ± 490 post 8 420 ± 2 410 + 5 260 ± 690 6 300 ± 1 930 4 480 ± 650 monocytes 0 800 cells/ul pre 530 ± 50 530 ± 30 470 ± 20 510 ± 30 post 730 ± 120 510 ± 70 630 ± 120 510 ± 30 lymphocytes 1 000 4 000 cells/ul pre 1 800 ± 200 1 800 ± 190 1 870 ± 300 1 730 ± 290 post 2 310 ± 280 1 710 ± 350 2 260 ± 510 1 830 ± 290 cd3 + 1 100 1 700 cells/ul pre 1 248 ± 143 1 201 ± 150 1 396 ± 208 1 197 ± 197 post 1 590 ± 220 1 179 ± 216 1 498 ± 292 1 238 ± 229 relative cd3 + % total lymphocytes pre 69.5 ± 3.9 66.3 ± 3.6 75.0 ± 2.7 69.4 ± 3.9 post 67.4 ± 5.3 68.5 ± 4.2 68.2 ± 4.3 65.6 ± 4.2 cd4 + 700 1 100 cells/ul pre 748 ± 99 692 ± 87 726 ± 118 760 ± 142 post 768 ± 109 650 ± 116 782 ± 146 748 ± 137 relative cd4 + % total lymphocytes pre 41.2 ± 1.5 38.9 ± 3.1 39.1 ± 1.5 43.7 ± 2.2 post 32.1 ± 1.0 38.1 ± 2.4 36.2 ± 2.4 39.4 ± 1.2 cd8 + 500 900 cells/ul pre 415 ± 66 429 ± 92 498 ± 93 393 ± 59 post 573 ± 52 364 ± 48 506 ± 105 418 ± 69 relative cd8 + % total lymphocytes pre 23.4 ± 3.0 23.2 ± 3.5 26.4 ± 3.3 23.2 ± 2.5 post 25.4 ± 2.6 22.4 ± 2.3 23.1 ± 2.3 22.7 ± 2.4 cd4 + :cd8 + 1.0 1.5 pre 1.88 ± 0.21 1.87 ± 0.30 1.61 ± 0.21 2.01 ± 0.24 post 1.33 ± 0.18 1.77 ± 0.22 1.60 ± 0.14 1.78 ± 0.18 bonferroni’s post hoc analysis: * value significantly increased from baseline: p < 0.05; + tendency for increase from baseline: p = 0.06. gs-d = glutamine-supplemented, prior glycogen-reducing exercise; gs-r = glutamine-supplemented, glycogen-replete and rested; ps-d = placebo-supplemented, prior glycogen-reducing exercise; ps-r = placebo-supplemented, glycogen-replete and rested. pg122-128.indd 127 11/23/06 4:09:01 pm 128 sajsm vol 18 no. 4 2006 16. miller al. therapeutic considerations of l-glutamine: a review of the literature. alternative medicine review 1999; 4: 239-48. 17. natale vm, brenner ik, moldoveanu ai, vasiliou p, shek p, shephard rj. effects of three different types of exercise on blood leukocyte count during and following exercise. sao paulo medical journal 2003; 121: 9-14. 18. nehlsen-cannarella sl, fagoaga or, nieman dc, et al. carbohydrate and the cytokine response to 2.5 h of running. j appl physiol 1997; 82: 1662-7. 19. nieman dc. immune response to heavy exertion. j appl physiol 1997; 82: 1385-94. 20. nieman dc, miller ar, henson da, et al. effects of highvs moderateintensity exercise on natural killer cell activity. med sci sports exerc 1993; 25: 1126-34. 21. nieman dc, nehlsen-cannarella sl, markoff pa, et al. the effects of moderate exercise training on natural killer cells and acute upper respiratory tract infections. int j sports med 1990; 11: 467-473. 22. parry-billings m, baigrie rj, lamont pm, morris pj, newsholme ea. effects of major and minor surgery on plasma glutamine and cytokine levels. arch surg 1992; 127: 1237-40. 23. parry-billings m, budgett r, koutedakis y, et al. plasma amino acid concentrations in the overtraining syndrome: possible effects on the immune system. med sci sports exerc 1992; 24: 1353-8. 24. rohde t, maclean da, klarlund pb. glutamine, lymphocyte proliferation and cytokine production. scand j immunol 1996; 44: 648-50. 25. rohde t, maclean da, pedersen bk. effect of glutamine supplementation on changes in the immune system induced by repeated exercise. med sci sports exerc 1998; 30: 856-62. 26. rohde t, ullum h, rasmussen jp, kristensen jh, newsholme e, pedersen bk. effects of glutamine on the immune system: influence of muscular exercise and hiv infection. j appl physiol 1995; 79: 146-50. 27. rowbottom dg, keast d, goodman c, morton ar. the haematological, biochemical and immunological profile of athletes suffering from the overtraining syndrome. eur j appl physiol 1995; 70: 502-9. 28. salehian b, kejriwal k. glucocorticoid-induced muscle atrophy: mechanisms and therapeutic strategies. endocr pract 1999; 5: 277-81. 29. shephard rj, shek pn. athletic competition and susceptibility to infection. clin j sport med 1993; 3: 75-7. 30. shinkai s, watanabe s, asai h, shek pn. cortisol response to exercise and post-exercise suppression of blood lymphocyte subset counts. int j sports med 1996; 17: 597-603. 31. smith ll. overtraining, excessive exercise, and altered immunity: is this a t helper-1 versus t helper-2 lymphocyte response? sports med 2003; 33: 347-64. 32. stapelfeldt b, schwirtz a, schumacher yo, hillebrecht m. workload demands in mountain bike racing. int j sports med 2004; 25: 294-300. 33. straub rh, schuld a, mullington j, haack m, scholmerich j, pollmacher t. the endotoxin-induced increase of cytokines is followed by an increase of cortisol relative to dehydroepiandrosterone (dhea) in healthy male subjects. j endocrinol 2002; 175: 467-74. 34. strauss jdw, myburgh k, kruger a, smith c, robson p. pre-exercise glutamine supplementation could prevent decreases in postexercise serum glutamine following a single bout of intensive exercise. south african journal of sports medicine 2001; 8: 12-6. 35. villette jm, bourin p, doinel c, et al. circadian variations in plasma levels of hypophyseal, adrenocortical and testicular hormones in men infected with human immunodeficiency virus. j clin endocrinol metab 1990; 70: 572-7. 36. walsh np, blannin ak, bishop nc, robson pj, gleeson m. effect of oral glutamine supplementation on human neutrophil lipopolysaccharide-stimulated degranulation following prolonged exercise. int j sport nutr exerc metab 2000; 10: 39-50. 37. walsh np, blannin ak, robson pj, gleeson m. glutamine, exercise and immune function. links and possible mechanisms. sports med 1998; 26: 177-91. 38. wisniewski tl, hilton cw, morse ev, svec f. the relationship of serum dhea-s and cortisol levels to measures of immune function in human immunodeficiency virus-related illness. am j med sci 1993; 305: 79-83. health & medical publishing group insall & scott’s surgery of the knee e-dition, 4th edition text with continually updated online reference, 2-volume set by w. norman scott, md, clinical professor of orthopaedic surgery, albert einstein college of medicine, bronx, ny; director, insall scott kelly institute for orthopaedics and sports medicine, new york, ny isbn 0443069611 · book/electronic media churchill livingstone · published january 2006 health & medical publishing group private bag x1, pinelands, 7430 tel: 021-6578200 fax: 021-6834509 e-mail: carmena@hmpg.co.za brents@hmpg.co.za health & medical books health & medical books pg122-128.indd 128 11/23/06 4:09:03 pm sajsm 561.indd sajsm vol. 26 no. 3 2014 93 case report � ere are few reported cases of cyclist’s nodule in females. � e condition has thus lent itself to synonyms such as third, supernumerary or accessory testicle. we report the imaging � ndings of a perineal nodule in a 29-year-old female patient who is a known cyclist, and discuss the di� erential diagnosis. s afr j sm 2014;26(3):93-94. doi:10.7196/sajsm.561 a case of cyclist’s nodule in a female patient n z makhanya,1 mb chb, mmed rad (diag), fcrad (diag) sa; m velleman,2 mb chb, mmed rad (diag), fc rad (diag); f e suleman,1 mb chb, mmed rad (diag), fcrad (diag) sa 1 department of radiology, steve biko academic hospital, pretoria, south africa 2 department of radiology, little company of mary, pretoria, south africa corresponding author: n z makhanya (makhanya.nz@gmail.com) a cyclist’s nodule is an infrequently diagnosed yet fairly common condition of the perineum, a� ecting cyclists. it therefore requires a high index of suspicion in patients who are known cyclists. it is typically a tender, firm, soft-tissue nodule, seldom exceeding 3 cm, located in the paramedian region of the perineum.[1] the overlying skin is usually normal, but may show features of cha� ng or chronic irritation. � e condition is predominantly described in males,[2] leading to it being termed a third, supernumerary or accessory testicle. other synonyms include perineal hygroma and perineal induration.[1] case report a 29-year-old female patient, a known cyclist, was referred for imaging following a complaint of a painful, palpable mass on the right inferomedial buttock region. ultrasound (us) examination showed a well-circumscribed, hetero genously hypoechoic, solid nodule in the subcutaneous tissues, inferior to the ischial tuberosity, adjacent to the common hamstring origin (fig. 1). � e nodule measured 12 mm × 7 mm × 15 mm and showed no � ow on doppler. a magnetic resonance image (mri) of the pelvis was also performed and showed a poorly circumscribed nodule, isointense to muscle on all sequences, in the right perineum (fig. 2). a diagnosis of a cyclist’s nodule was made based on the clinical history, the typical location of the lesion and the radiological � ndings. � e patient was managed conservatively with analgesia and advised to give up cycling. she was reluctant to give up the sport and opted to change the saddle, which, on follow-up, appears to have helped. discussion a cyclist’s nodule is believed to be as a result of repeated microtrauma from vibration and friction between the ischial tuberosities and the saddle, with constant rubbing of the super� cial perineal fascia against the bony structures.[1] � is induces a combination of fat necrosis, collagen degeneration, myxoid changes and sometimes pseudocyst formation. [3] although histologically few blood vessels are seen, the lesion is not well vascularised. � e nodules are usually � xed to the underlying deep so� tissues and are covered by normal skin.[1] � e absence of clinical features of infection excludes the diagnosis of an abscess, a common condition in this region. rarely, in females, the vulva may demonstrate unilateral lymphoedema of the labia majora, which is attributed to the combination of chronic in� ammation and damaged lymphatic � ow to the vulvoperineal and inguinal lymphatic vessels.[3] symptoms include pain on pressure and when sitting on the saddle, which may even require the cyclist to give up the sport. conservative management such as local corticosteroid injection is described; however, de� nitive treatment involves removing the causative agent. � e lesions have been reported to recur, even a� er excision. fig. 1. ultrasound showing a well-circumscribed hypoechoic oval lesion (measured). note the posterior acoustic shadow cast by the adjacent ischeal tuberosity (arrow). 94 sajsm vol. 26 no. 3 2014 most articles report the histological characteristics of the lesions more than the imaging characteristics. if the diagnosis is suspected, then the imaging modality of choice is us, where the diagnosis can be made with certainty. us demonstrates a hypoechoic solid nodule, without any increased doppler signal. small internal cystic and/or fatty areas may also be seen, giving the nodule a slightly heterogenous appearance, as in our patient. on computed tomography and mri, this hypovascular lesion should show no uptake of contrast agent. �e primary role of imaging is to determine the exact extent of the lesion, and in most cases, us will su�ce for imaging evaluation. imaging has an additional role in the di�erentiation between cyclist’s nodule and other causes of perineal swelling. �e di�erential diagnosis includes abscess, epidermal cyst, and benign and malignant tumours (�broma, so�-tissue sarcoma or metastasis). [3] �e mri was performed at no cost to the patient, for academic purposes of demonstrating the mri features of a known cyclist nodule. for this reason, no contrast was given. a �uid-sensitive sequence was performed in order to evaluate for features of acute in�ammation. �e sonographic �ndings were more obvious than the mri �ndings, where the lesion, being isointense to adjacent soft tissues on all sequences, was fairly di�cult to locate. conclusion recreational history of cycling should be sought in all patients, including females, when a non-infective so�-tissue nodule in the perineal region is seen, as the diagnosis could be a cyclist’s nodule. references 1. van de perre s, vanhoenacker fm, vanstraelen l, gaens j, michiels m. perineal nodular swelling in a recreational cyclist: diagnosis and discussion. skeletal radiol 2009;38:933-934. [http://dx.doi.org/10.1007/s00256-009-0731-9] 2. mccluggage wg, smith jh. reactive �broblastic and myo�broblastic proliferation of the vulva (cyclist’s nodule): a hitherto poorly described vulval lesion occurring in cyclists. am j surg pathol 2011;35:110-114. [http://dx.doi.org/10.1097/ pas.0b013e3181�d8ab] 3. leibovitch i, mor y. �e vicious cycling: bicycling related urogenital disorders. eur urol 2005;47(3):277-286. [http://dx.doi.org/10.1016/j.eururo.2004.10.024] a b fig. 2. (a) t1 coronal mri demonstrating the cyclist’s nodule (arrow) as a homogenous lesion, in the right perineal region, which is isointense to muscle. (b) �e �uid-sensitive sequence coronal mri shows the cyclists’ nodule (arrow) as a poorly de�ned nodule, isointense to the overlying subcutaneous fat. no oedema is noted surrounding the nodule. (mri = magnetic resonance image.) sajsm 595 (commentarty).indd commentary 87 sajsm vol. 28 no. 3 2016 good versus bad medical stoppages in boxing: stopping a fight in time n k sethi, md department of neurology, new york presbyterian hospital, weill cornell medical center, new york, usa corresponding author: n k sethi (sethinitinmd@hotmail.com) in the boxing fraternity it is commonly said and not without reason “…the fight must go on…”.everyone ringside wants the fight to continue the two boxers and their corners (sometimes not always), the promoter (always), the media (always), the spectators (always), the commission and its appointed officials (only if both the boxers meet the commission requirements for a fair and honestly administered contest), the referee (only if the boxers are fighting a fair fight and able to defend themselves), the judges (usually do not interfere with the conduct of the fight) and the ringside physicians (only if the boxers are medically fit before, during and immediately after the contest). as per the uniform boxing rules (approved august 25, 2001, amended august 2, 2002, amended july 3, 2008, amended july 24, 2012, amended july 29, 2014), the referee is the sole arbiter of a bout and the only individual authorised to stop a contest.[1]in some states in the united states and in other countries around the world, both the referee and ringside physician are the sole arbiters of a fight and the only ones authorised to enter the fighting area at any time during the competition and to stop a fight. the referee and the ringside physician’s threshold to stop a fight may vary based on their knowledge of boxing rules and regulations, knowledge of the boxers’ fitness level, pre-existing medical conditions, pre-bout fitness, intra-bout fitness and finally, knowledge of their medical condition and bout-ending injuries (for example, head injuries, orthopaedic injuries, eye injuries, blunt abdominal trauma). for these reasons it is the referee (someone who has knowledge of boxing rules and regulations) and the ringside physician (someone who has knowledge of medicine) who are deemed to be the sole arbiters of a bout and entrusted with the health and safety of the boxers. a most important question is when the fight should be stopped on medical grounds. stopping a bout prematurely is unfair to the boxers, their corners, the promoters and the public. stopping a bout too late may risk serious injury and even the possible death of the boxer. boxer safety should precede all other considerations. the goal should be to stop a bout before a life-threating injury or career-ending injury occurs. since there are times when this is not possible, a more realistic goal should be the timely identification of a serious injury in the ring followed by the stoppage of the fight. it is therefore essential that the referee and the ringside physician work as a team, complimenting each other’s knowledge. causes of sudden death in the ring or in the immediate aftermath of a bout are usually neurological.[2] in order to identify and prevent tbi in boxing, the following good practice guidelines are proposed based on personal and collective evidence of experienced ringside physicians and clinical acumen: 1. it is a good point to remember that boxers rarely, if ever, voluntarily quit or request that the fight be stopped. they fight for pride, at times at the expense of their health. corners may also not want the fight to be stopped hoping that their boxer may turn things around. in a closely contested fight the crowd is excited and wants the fight to continue. this is when the ringside physician should stop the fight or let it continue, based solely on the medical condition of the boxer. 2. during the one-minute rest period between rounds, the ringside physician should step up to the ring for a quick but thorough medical evaluation of the fighter. this is the ideal time for the ringside physician to assess the neurological status of a fighter. background: professional boxing is a popular contact sport with a high risk for both acute and chronic traumatic brain injury (tbi). although rare, many boxers have died in the ring or soon after the completion of a bout. the most common causes of death in these cases are usually acute subdural hematomas, acute epidural hematomas, a subarachnoid haemorrhage, an intracranial haemorrhage or second impact syndrome (sis). ringside physicians are entrusted with the health and safety of boxers in the ring and in the immediate aftermath of a bout. discussion: as per the uniform boxing rules (approved august 25, 2001, amended august 2, 2002, amended july 3, 2008, amended july 24, 2012, amended july 29, 2014), the referee is the sole arbiter of a bout and is the only individual authorised to stop a contest. [1]in some states in the united states and in other countries around the world, the referee and the ringside physician are the sole arbiters of a fight and the only individuals authorised to enter the fighting area at any time during the competition and also authorised to stop a fight. this raises the important question of when should a fight be stopped on medical grounds. conclusion: standardising medical stoppage decisions in boxing will help to protect a boxer’s health and safety in the ring. good practice guidelines for medical stoppage due to suspected tbi are suggested. it is recommended that the medical community debate the proposed guidelines vigorously, in order that evidence-based guidelines can be developed in conjunction with professional boxing governing bodies. keywords: safety, concussion, knockout, traumatic brain injury, contact sports s afr j sports med 2016;28(3):87-89.doi:10.17159/2078-516x/2016/v28i3a1735 http://dx.doi.org/10.17159/2078-516x/2016/v28i3a1735 commentary sajsm vol. 28 no. 3 2016 88 3. in the case of a fighter who had suffered a knock-down in the preceding round or sustained multiple head shots, the ringside physician should conduct a quick visual evaluation of the fighter (is the fighter responding appropriately to the commands and directions of his corner? is he making eye contact with his corner staff? was the fighter steady on his feet as he walked back to his corner at the end of the round? does the fighter voice any problems to his corner staff, such as headache or pressure in head, dizziness, or blurred vision?). the ringside physician should attempt to do the above evaluations without obstructing or imposing on the corner’s time with its fighter. 4. if the ringside physician determines that he/she needs more time to evaluate the neurological status of a fighter, he/she should communicate this to the referee. the referee, after starting the bout, shall call a time-out and walk the fighter to the ringside physician to be examined. the referee will then direct the other fighter to remain in the neutral corner. the ringside physician’s goal at this time is to conduct a quick but thorough neurological assessment of the fighter. he/she should begin this by asking the fighter a few leading questions, such as-how do you feel? does your head hurt? do you know where you are? if the fighter appears confused and disorientated, the ringside physician may ask more questions such as: which round is this? who is your opponent? where are you fighting (the name of the venue)? the ringside physician should then look for pupil symmetry and response, and assess extraocular movements (have the fighter track a finger from side to side). the ringside physician should then give the fighter a complex command, such as touch your left ear with your right glove. the physician should also assess the fighter's gait and balance at the same time (is the fighter steady on his/her feet or is he leaning on the ropes for support?). the ringside physician should then communicate to the referee whether the fighter can continue or that the fight be stopped. the whole process should not take more than 10 seconds. 5. the ringside physician should be aware that too much time spent evaluating the fighter during time -out, inadvertently gives the fighter more time to recover. the opponent’s corner rightfully resents this as it is akin to being "saved by the bell". the public, tv audience, press and tv announcers question the fairness of the commission’s administration of the contest and the credibility and impartiality of the bout officials, e.g., referees, judges and ringside physicians. 6. if a serious health concern is raised for a fighter and the ringside physician is unable to document a good exam to determine whether it is safe for the fighter to continue, consideration should be given to stopping the fight. under these circumstances the ringside physician should tell the referee that the fight be stopped on medical grounds. 7. for ringside physicians with limited ringside experience, it is encouraged that they consult with other ringside physicians at the venue and the chief medical officer before the decision is taken to stop a fight on medical grounds. as injuries mount, the boxing community is looking within itself and the sport is under scrutiny from the medical community and the media. boxing is the most controversial sport for physicians and neurologists in particular because of the potential risk and degree of neurologic injury, questions and concerns about long-term sequelae (chronic traumatic encephalopathy), and the occurrence of deaths in the ring.[3] various medical associations including the american medical association and the american academy of paediatrics have stated opposition to both amateur and professional boxing.[4] many have called to ban boxing altogether.[5,6] dr. hauser in a recent editorial titled “beaten into action: a perspective on blood sports” said that “…the medical, and especially the neurology, community has an obligation to do more. we need to spread the word that brain bashing is not a socially acceptable spectator sport, and partner with our national organizations to expand and improve the effectiveness of public awareness and other educational initiatives.” [7] he further goes on to state that “…we should forcefully counter articles in the medical literature taking the position that closer medical supervision could obviate the need for a ban, or even worse that consenting adults have the ethical right to maim each other if they choose to do so.” [7] while the neurological risks of boxing cannot be completely eliminated, boxing can be made safer.[8, 9] conclusion it is recommended that the above proposed best practice guidelines be debated vigorously by ringside physicians and the wider scientific community and that evidence-based guidelines on medical stoppages be developed by the medical community in conjunction with the professional boxing governing bodies. boxing can be made safer but it shall be foolhardy to forget that frequently there is a very fine line between a good medical stoppage (i.e. medical stoppage done at the right time during the bout and for the right indication) versus a bad medical stoppage (i.e. medical stoppage done either too late, too prematurely, or for the wrong indication). it is far better to stop a fight early rather than too late. a ringside physician should never forget that in boxing one punch can change everything. disclosure: the author serves as an associate editor, the eastern journal of medicine and as chief medical officer to the new york state athletic commission (nysac). the views expressed are his and do not represent the views of the nysac. references 1. association of boxing commissions. uniform rules of boxing (approved august 25, 2001, amended august 2, 2002, amended july 3, 2008, amended july 24, 2012, amended july 29, 2014) 2. baird lc, newman cb, volk h, et al. mortality resulting from head injury in professional boxing. neurosurgery 2010; 67:1444-1450; discussion 1450. [doi: 10.1227/neu.0b013e3181e5e2cd] https://www.ncbi.nlm.nih.gov/pubmed/20948404 https://www.ncbi.nlm.nih.gov/pubmed/20948404 commentary 89 sajsm vol. 28 no. 3 2016 3. mccrory p, zazryn t, cameron p. the evidence for chronic traumatic encephalopathy in boxing. sports med 2007; 37(6):467-476. review. [http://dx.doi.org/10.2165/00007256-200737060-00001] 4. pearn j. boxing, youth and children. j paediatr child health 1998; 34(4):311-313. [http://dx.doi.org/10.1046/j.1440-1754.1998.00231.x] 5. rudd s, hodge j, finley r, et al. should we ban boxing? bmj 2016; 352:i389. [http://dx.doi.org/10.1136/bmj.i389] 6. hagell p. should boxing be banned? j neurosci nurs 2000; 32(2):126128. [http://dx.doi.org/10.1097/01376517-200004000-00009] 7. hauser sl. beaten into action: a perspective on blood sports. ann neurol 2012; 72(3):a4-a5. [http://dx.doi.org/10.1002/ana.23743] 8. gillon r. doctors should not try to ban boxing--but boxing's own ethics suggests reform. j med ethics 1998; 24:3-4. [http://dx.doi.org/10.1136/jme.24.1.3] 9. sethi nk. boxing can be made safer. ann neurol 2013; 73(1):147. [http://dx.doi.org/10.1002/ana.23807] https://www.ncbi.nlm.nih.gov/pubmed/17503873 https://www.ncbi.nlm.nih.gov/pubmed/17503873 https://www.ncbi.nlm.nih.gov/pubmed/9727167 https://www.ncbi.nlm.nih.gov/pubmed/26818415 https://www.ncbi.nlm.nih.gov/pubmed/10826299 https://www.ncbi.nlm.nih.gov/pubmed/23034920 https://www.ncbi.nlm.nih.gov/pubmed/9549674 https://www.ncbi.nlm.nih.gov/pubmed/9549674 https://www.ncbi.nlm.nih.gov/pubmed/?term=sethi%20nk%5bauthor%5d&cauthor=true&cauthor_uid=23378329 https://www.ncbi.nlm.nih.gov/pubmed/?term=sethi+boxing+can+be+made+safere original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license 24 hour movement behaviours and the health and development of pre-school children from zimbabwean settings: the sunrise pilot study n munambah,1 msc, p gretschel,2 phd; f muchirahondo,3 mbchb, med; m chiwaridzo,1 phd; t chikwanha,1 phd; ke kariippanon,4 phd; kh chong,4 ms; pl cross,4 be (matl); ce draper,5,6 phd; ad okely,4 edd 1 rehabilitation unit, department of primary health sciences, faculty of medicine, university of zimbabwe, zimbabwe 2 division of health and rehabilitation sciences, faculty of health sciences, university of cape town, south africa 3 mental health unit, department of primary health sciences, faculty of medicine, university of zimbabwe, zimbabwe 4 early start, school of health and society, faculty of the arts, humanities and social sciences, university of wollongong, nsw, australia 5 south african mrc developmental pathways for health research unit, university of the witwatersrand, south africa 6 division of exercise science and sports medicine, uct research centre for health through physical activity, lifestyle and sport, university of cape town, south africa corresponding author: n munambah (nyariemnambah02@gmail.com) promoting healthy movement behaviours (physical activity, sedentary behaviour and sleep) during a child’s early years (0 5 years) is fundamental to the development of each child, as it sets a foundation for facilitating and maintaining a healthy and active lifestyle throughout adulthood. [1] the world health organization’s (who) ending childhood obesity (echo) report highlighted the need to address 24hour movement behaviours in early childhood for the prevention and management of obesity and noncommunicable diseases (ncds). [2] following this, who developed global guidelines on physical activity, sedentary behaviour and sleep for children under five years of age which states that “pre-schoolers should be involved in at least 180 min of total physical activity (tpa) of which 60 min are spent in moderate to vigorous physical activity (mvpa) per day; (ii) screen time should be no more than one hour per day; and (iii) sleep duration between 10 to 13 h (including naps” [3]. canada, australia and south africa have also developed guidelines for physical activity, sedentary behaviour and sleep for the early years. [4-6] in sub-saharan africa, rapid socio-cultural developments and urbanisation have resulted in a shift from traditional active lifestyles to more industrialised and sedentary lifestyles. [7] this has resulted in a decline in physical activity levels and an increase in sedentary behaviours mainly in adults, but with consequential effects on children. [7] according to the report card (global matrix 3.0) these risks could be high in zimbabwe, where there is a double burden of malnutrition and associated childhood obesity*. [8] despite the notable risks of overweight and obesity in children, few studies, most of which use selfreported measures, have been conducted in zimbabwe. [9] there is a paucity of literature on physical inactivity and other movement behaviours as indicators for the prevention of ncds among children in zimbabwe. [8] the international study of movement behaviours in the early years (sunrise), (https://sunrise-study.com) aims to determine the proportion of children sampled in participating countries who meet the who global guidelines for physical background: in 2019, the world health organization (who) released global guidelines for physical activity, sedentary behaviour and sleep for the early years. the international study of movement behaviours in the early years, sunrise, aimed to assess the extent to which children aged three and four years meet the who global guidelines and its association with health and development. objectives: to assess movement behaviours in pre-school children from low-income settings in zimbabwe and to establish associations between these movement behaviours and adiposity, motor skills and executive function. methods: pre-school children/caregivers were recruited from two urban and two rural public schools respectively in zimbabwe. the caregivers answered questions on the children’s physical activity, screen time, sedentary behaviour and sleep patterns. children’s movement behaviours were objectively measured using accelerometers. gross and fine motor skills and executive function were assessed using the ages and stages questionnaire-3 and early years toolbox, respectively. focus group discussions were carried out with caregivers and teachers on the acceptability and feasibility of the study. results: eighty-one children participated in the study. the proportions of children meeting the guidelines were physical activity 92%, sedentary behaviour 70%, and sleep 86%, and all guidelines combined 24%. boys and girls were similar (p>0.05 for all variables) for all executive function variables, but rural children had significantly lower inhibition scores (p=0.026) than urban children. conclusion: the study adds to the growing literature on movement behaviours and associated risk factors in low-resourced settings. further investigations of movement behaviours in this age group in zimbabwe are recommended. keywords: early childhood development, physical activity, screen time, sleep s afr j sports med 2021;33:1-9. doi: 10.17159/2078-516x/2021/v33i1a10864 * undernutrition is synonymous with malnutrition which denotes insufficient intake of energy and nutrients to meet an individual's needs to maintain good health. forms of undernutrition include wasting, stunting, underweight and deficiencies in vitamins and minerals. mailto:nyariemnambah02@gmail.com https://sunrise-study.com/ http://dx.doi.org/10.17159/2078-516x/2021/v33i1a10864 https://orcid.org/0000-0002-7890-3635 https://orcid.org/0000-0002-3963-2107 https://orcid.org/0000-0002-0957-3783 https://orcid.org/0000-0002-3893-4306 https://orcid.org/0000-0003-4269-682x https://orcid.org/0000-0003-3244-5277 https://orcid.org/0000-0002-2885-437x https://orcid.org/0000-0002-1626-8170 https://orcid.org/0000-0003-4470-9604 https://orcid.org/0000-0002-6941-4696 original research sajsm vol. 33 no. 1 2021 2 activity, sedentary behaviour and sleep for children under five years of age. previously published sunrise studies in other countries have shown that a low proportion of children are meeting the who guidelines. [10] this paper on the zimbabwean sunrise pilot study presents descriptive findings on movement behaviours in pre-school children from low-income urban and rural settings, and the associations between these movement behaviours and adiposity, motor skills and executive function (ef). methods ethical approval a cross-sectional design was used in this study. ethical clearance was obtained from the medical research council of zimbabwe (a/2385) and the parirenyatwa joint research ethics committee (jrec 203/18). all public pre-schools in zimbabwe are governed by the ministry of primary and secondary education, each of which is attached to a primary school. thus, permission to access the pre-schools was sought from the ministry of primary and secondary education and the respective primary school authorities. setting this study took place at two rural and two urban public primary pre-schools registered by the ministry of primary and secondary education in zimbabwe. most rural areas do not have electricity, and children walk long distances to get to school. the urban areas are characterised by many cars, and electricity and water is readily available. [11] the study was conducted during the summer period (september 2018 march 2019). caregivers were invited to the school for a meeting where information about the study was provided and an appointment was set with each of the caregivers who expressed willingness to take part in the study. with the assistance from teachers, eligible children were invited to participate in the study. written informed consent was obtained from parents/caregivers for the children to participate in the study. participants children were eligible to participate if they were aged between four and five years, could wear an accelerometer, attended early childhood development (ecd) education at the selected pre-schools, and if their primary caregivers were available to give consent and to respond to the questionnaire. measures and procedures prior to data collection, four fieldworkers were trained in all aspects of the study’s protocol. data collection from the children took place at each respective pre-school. the parent questionnaire was administered by trained field workers regarding the children either at home or at the child’s school. anthropometry the children’s height and weight were measured using a portable stadiometer (leicester 214 transportable stadiometer; seca, germany) and a calibrated scale (soehnle 7840 mediscale digital; soehnle industrial solutions, germany). all measurements were taken twice and the average was used for analysis. height and weight were used to calculate the body mass index (bmi). bmi and associated z-scores for bmi-for-age (baz), height-for-age (haz) and weight-for-age (waz) were computed using the who anthroplus software (http://www.who.int/growthref/tools/en/). accelerometry an activpal accelerometer was used to assess the 24-hour movement behaviours of the children. the activpaltm (pal technologies ltd, glasgow, uk), a small lightweight (15g) device, recorded the child’s sitting/lying, standing, and walking, transitions and step count. each child wore the activpal on the right thigh continuously for 72 hours. throughout the school day teachers also assisted with the monitoring and checking for compliance. the accelerometry data was processed using the crea algorithm of the activpal’s data processing software, palbatch (version 8.10.9.43, pal technologies ltd., glasgow, scotland). activity events were classified into seven main categories: total sitting/lying, standing, stepping and sleep time, number of bouts of sitting >30 min and time spent in motorised transport, based on thigh position and dynamic acceleration information. furthermore, periods of sitting in motorised transport were identified (based on the presence of dynamic components in the acceleration signals from a seated event), and quantified periods of nonwear time (based on a measure of stillness of ≥60 min). total sedentary behaviour was calculated by combining total sitting, and restrained sitting and lying times. only participants with at least 20 h per day of wear data were included in the final analysis. [12] motor skills in this study, motor skills included gross and fine motor skills. the ages and stages questionnaire-3 (48 months, asq-3) was used to collect data on the gross and fine motors skills of the child. [13] each child was asked to perform tasks as guided by the asq-3, and the research assistants observed and scored the performance of the child. the tasks for gross motor skills included catching a ball with both hands, throwing a ball overhead, and jumping forward over a distance of 50.8 cm from a standing position. the fine motor tasks assessed were: completing a wooden puzzle, cutting a piece of paper in half using a pair of scissors, unbuttoning one or more buttons of a shirt provided, drawing shapes on a piece of paper, and colouring in a shape using crayons. executive function (ef) tests in this study, ef tests were performed to assess the cognitive flexibility (shifting), control of behavioural urges and impulses (inhibition), and visual-spatial working memory of children using three short, ipad-based tools called the early years toolbox (eyt). [14] the research assistant explained the games and participants practised for 10 minutes before recording was started. for each child, all three tasks were performed on an ipad using the same order. the tasks were performed in a quiet environment and took 20 minutes to complete per child. an original research 3 sajsm vol. 33 no. 1 2021 exploratory factor analysis (efa)-derived factor score (ef composite score) was computed for the three eyt tasks. parent questionnaire a parent questionnaire was developed and used to report basic sociodemographic data. the version of the parent questionnaire used in this study was the same as that used for all countries who participated in phase 1 of the sunrise study. the parent questionnaire was translated into shona and ndebele (the most common local languages) and parents were asked to choose the language they were most comfortable in. parents/caregivers were also asked to report on their child’s use of electronic media (to calculate sedentary screen time), sleep quality, and restrained sitting time. focus group discussions an interview guide was used to conduct four focus group discussions with purposively selected caregivers of children involved in the study. on average, each focus group discussion had nine caregivers and lasted between 45-60 minutes. participants were asked about their experience with the data collection procedures, and the feasibility and acceptability of the selected instruments measuring movement behaviours. statistical analysis all analyses were performed using spss (v25.0, ibm corp, armonk, ny). descriptive statistics were calculated using the mean and standard deviations (and median and interquartile range if not normally distributed) for continuous variables, and the frequency and percentage for categorical variables. the differences between boys and girls and all the children from urban or rural areas were examined using independent t-tests or mann-whitney u tests for continuous variables, and chi-square or fisher’s exact tests for categorical variables respectively. the correlations between accelerometer measures and baz, motor skills and executive functions were determined using the spearman’s rank correlation coefficients. the differences in baz, motor skills and executive functions between meeting and not meeting movement behaviour guidelines (individual and integrated) were tested using mann-whitney u tests. statistical significance was set at p<0.05. data from the focus group discussions was transcribed verbatim and translated from the local languages to english. thematic analysis was used to analyse the data. [15] results the analytical sample was comprised of 81 children (n = 41 girls, 51%; n = 40 boys, 49%; n = 45 rural, 56%) from four preschools (table 1). no significant differences were found between boys and girls for any anthropometric outcomes (all p > 0.05). according to the who cut-offs, 64% were in the normal bmi range, 12% were underweight, 15% overweight and 9% were obese. compared with urban children, rural children had lower bmi, baz, and waz scores (p<0.0005). accelerometry, motor skills and executive function results are summarised in table 2. boys accrued a higher total stepping time (p=0.012) than girls. the differences between boys and girls across other movement behaviours were not statistically significant. compared with urban children, those from rural areas had a higher total stepping time (p=0.025). there were no differences between boys and girls for any of the motor skill; however, urban children had significantly higher fine motor skill scores (p<0.0005) compared to their rural peers. for gross and fine motor skills, 86% and 42% of children were developmentally ‘on track’, respectively. boys and girls were similar for all ef variables, but rural children had significantly lower inhibition scores (p=0.026) than urban children. more rural than urban children had fine motor skills categorised as at-risk or delayed. table 3 presents the results of the parent questionnaire. differences between boys and girls for movement behaviours were small and not statistically significant. compared with their urban peers, children in rural areas reported significantly more tpa (p = 0.002) and less screen time (p = 0.006), less sedentary time, (p <0.0001), and less time sitting in a vehicle on table 1. sample age and anthropometric characteristics, by sex and setting total (n=81) boys (n=40) girls (n=41) p value‡ rural (n=45) urban (n=36) p value§ age (y) 5.2 ± 0.5 5.2 ± 0.4 5.1 ± 0.5 0.290 5.1 ± 0.5 5.2 ± 0.4 0.097 height (cm) 106.8 ± 4.4 107.3 ± 4.7 106.3 ± 4.2 0.309 106.2 ± 4.6 107.5 ± 4.2 0.193 weight (kg) 17.5 ± 2.8 17.0 (16.0 – 19.0) 17.9 ± 2.9 17.8 (16.0 – 20.0) 17.0 ± 2.7 17.0 (15.5 – 19.0) 0.165 15.8 ± 2.0 16.0 (14.0 – 17.0) 19.5 ± 2.5 19.0 (18.0 – 20.4) <0.0005* bmi (kg.m-2) 15.3 ± 2.3 14.9 (13.9 – 16.6) 15.6 ± 2.6 15.0 (14.0 – 17.0) 15.0 ± 1.9 14.7 (13.6 – 16.5) 0.377 14.1 ± 1.5 14.2 (13.0 – 14.9) 16.9 ± 2.1 16.6 (15.2 – 17.9) <0.0005* haz -0.76 ± 1.10 (-1.52 – -0.08) -0.79 ± 1.24 -0.74 (-1.76 – -0.14 ) -0.72 ± 0.96 -1.02 (-1.28 – 0.00) 0.643 -0.78 ± 1.18 -0.89 (-1.54 – -0.05) -0.72 ± 1.02 -0.92 (-1.51 – -0.17) 0.890 waz -0.55 ± 1.16 -0.46 ± 1.22 -0.65 ± 1.10 0.465 -1.18 ± 0.93 0.22 ± 0.92 <0.0005* baz -0.15 ± 1.60 0.04 ± 1.84 -0.32 ± 1.32 0.313 -1.03 ± 1.27 0.97 ± 1.23 <0.0005* data are presented as mean ± sd for normally distributed data; not normally distributed data also includes median (25th – 75th percentile). * indicates significance at p<0.0005; ‡p value for comparison by sex; §p value for comparison by setting. bmi, body mass index; haz, height-for-age z-score; waz, weight-for-age z-score; baz, bmi-for-age z-score. original research sajsm vol. 33 no. 1 2021 4 dsdsadsadasd table 2. accelerometer measures, motor skills and executive function results, by sex and setting accelerometer measures total (n=58) boys (n=30) girls (n=28) p value‡ rural (n=36) urban (n=22) p value§ total stepping (min/day) 228.2 ± 43.1 241.7 ± 38.7 213.7 ± 43.6 0.012* 238.0 ± 42.6 212.1 ±39.9 0.025* total standing (min/day) 258.5 ± 41.0 252.3 ± 39.8 265.1 ± 41.9 0.235 255.3 ± 41.6 263.6 ± 40.2 0.459 total sitting (min/day) 323.5 ± 62.4 324.2 ± 60.7 322.8 ± 65.3 0.930 312.9 ± 56.0 340.9 ± 69.5 0.097 lying (min/day) 23.2 ± 50.8 0.0 (0.0 – 31.8) 20.4 ± 44.6 0.0 (0.0 – 8.0) 26.3 ± 57.4 0.0 (0.0 – 36.1) 0.707 20.4 ± 51.6 0.0 (0.0 – 0.0) 27.9 ± 50.3 0.0 (0.0 – 41.7) 0.405 total sb (min/day) 385.2 ± 84.9 379.7.1 ± 91.0 391.3 ± 78.8 0.370 385.2 ± 81.4 385.0 ± 92.0 0.630 bouts >30 min 0.26 ± 0.61 0.00 (0.00 – 0.00) 0.37 ± 0.72 0.00 (0.00 – 1.00) 0.14 ± 0.45 0.00 (0.00 – 0.00) 0.129 0.17 ± 0.45 0.00 (0.00 – 0.00) 0.41 ± 0.80 0.00 (0.00 – 1.00) 0.192 motorised transportation (min/day) 39.7 ± 32.4 30.8 (16.8 – 53.1) 41.5 ± 33.9 33.2 (16.8 – 55.0) 37.8 ± 31.2 29.8 (16.5 – 51.9) 0.663 41.1 ± 34.6 31.0 (16.7 – 59.0) 37.5 ± 29.0 30.8 (18.9 – 51.9) 0.873 sleep (min/day) 605.0 ± 65.1 606.8 ± 74.0 603.2 ± 55.3 0.835 586.5 ± 62.4 585.3 ± 63.5 0.070 motor skills total (n=78) boys (n=39) girls (n=39) p value‡ rural (n=42) urban (n=36) p value§ gross motor skills 55.9 ± 7.4 60.0 (54.0 – 60.0) 55.3 ± 8.7 60.0 (54.0 – 60.0) 56.6 ± 5.8 60.0 (54.0 – 60.0) 0.811 56.7 ± 7.2 60.0 (58.5 – 60.0) 55.0 ± 7.6 60.0 (49.5 – 60.0) 0.173 fine motor skills 40.5 ± 12.7 38.9 ± 12.5 42.2 ± 12.7 0.247 33.5 ± 10.5 48.8 ± 9.7 <0.0005** executive function total (n=78) boys (n=39) girls (n=39) p value‡ rural (n=42) urban (n=36) p value§ working memory† 1.09 ± 1.01 1.00 (0.00 – 2.00) 1.14 ± 1.17 0.83 (0.0 – 2.08) 1.03 ± 0.81 1.00 (0.08 – 1.83) 0.930 0.90 ± 0.83 1.00 (0.00 – 1.33) 1.30 ± 1.16 1.50 (0.00 – 2.08) 0.144 inhibition† 0.59 ± 0.22 0.57 ± 0.21 0.60 ± 0.22 0.569 0.54 ± 0.20 0.65 ± 0.22 0.026* shifting† 5.34 ± 4.49 4.00 (0.00 – 9.00) 5.50 ± 4.41 5.00 (1.00 – 9.00) 5.18 ± 4.61 4.00 (0.00 – 9.00) 0.689 5.51 ± 4.23 7.00 (1.50 – 9.00) 5.12 ± 4.85 4.00 (0.00 – 10.00) 0.712 data are presented as mean ± sd for normally distributed data; not normally distributed data also includes median (25th – 75th percentile). *indicates significance at p<0.05; **indicates significance at p<0.0005; ‡p value for comparison by sex; §p value for comparison by setting. sb, sedentary behaviour (sitting, restrained sitting and lying combined); ef, executive function; † indicates missing data for working memory (n=4; 1 boy and 3 girls; 2 from rural setting and 2 from urban setting), inhibition (n=2; 1 boy and 1 girl; 1 from rural setting and 1 from urban setting), shifting (n=4; 3 boys and 1 girls; 1 from rural setting and 3 from urban setting). table 3. parent questionnaire (continuous variables), by sex and setting total (n=74) boys (n=35) girls (n=39) p value‡ rural (n=44) urban (n=30) p value§ tpa (hr/d) 6.4 ± 2.3 8.0 (4.0 – 8.1) 6.6 ± 2.3 8.0 (4.5 – 8.0) 6.2 ± 2.4 7.3 (4.0 – 8.3) 0.646 7.1 ± 1.9 8.0 (6.3 – 8.3) 5.3 ± 2.5 5.5 (2.9 – 8.0) 0.002* mvpa (hr/d) 2.7 ± 2.0 2.3 (1.0 – 4.0) 2.6 ± 2.0 2.2 (1.0 – 4.0) 2.8 ± 2.0 2.3 (1.0 – 4.0) 0.572 2.8± 2.2 2.1 (1.0 – 3.9) 2.7 ± 1.7 2.6 (1.0 – 4.0) 0.847 screen time (hr/d)† 1.6 ± 1.6 1.0 (0.3 – 2.4) 1.6 ± 1.8 1.0 (0.0 – 2.5) 1.6 ± 1.5 1.0 (0.3 – 2.4) 0.697 1.1 ± 1.3 0.8 (0.0 – 2.0) 2.2 ± 1.9 1.5 (0.8 – 4.0) 0.006* sleep (hr/d)† 10.3 ± 1.5 10.5 ± 1.3 10.1 ±1.6 0.247 10.6 ± 1.6 10.0 ± 1.1 0.056 time spent sitting (hr/d)† 1.8 ± 2.2 1.0 (0.4 – 2.2) 1.3 ± 1.3 1.0 (0.3 – 2.0) 2.3 ± 2.7 1.0 (0.5 – 3.3) 0.211 1.1 ± 2.0 0.5 (0.3 – 1.1) 2.8 ± 2.1 2.0 (1.0 – 5.0) <0.0001** time spent sitting in a vehicle (weekdays, hr/d) 0.8 ± 1.8 0.0 (0.0 – 1.0) 1.1 ± 2.4 0.0 (0.0 – 1.0) 0.6 ± 1.2 0.0 (0.0 – 1.0) 0.686 0.2 ± 0.4 0.0 (0.0 – 0.1) 1.8 ± 2.6 0.8 (0.0 – 2.0) <0.0001** time spent sitting in a vehicle (weekends, hr/d) 0.5 ± 0.7 0.0 (0.0 – 1.0) 0.5 ± 0.7 0.0 (0.0 – 1.0) 0.5 ± 0.9 0.0 (0.0 – 1.0) 0.842 0.4 ± 0.8 0.0 (0.0 – 0.5) 0.7 ± 0.6 0.6 (0.0 – 1.0) 0.007* data are presented as mean ± sd and median (25th – 75th percentile). *indicates significance at p<0.01; **indicates significance at p<0.0001; ‡p value for comparison by sex; §p value for comparison by setting. tpa, total physical activity; mvpa, moderate-vigorous intensity physical activity; † indicates missing data for screen time (n=1; 1 girl from urban setting), sleep (n=2; 2 girls from urban setting), time spent sitting (n=1; 1 boy from urban setting). original research 5 sajsm vol. 33 no. 1 2021 weekdays (p <0.0001) and weekends (p = 0.007). figure 1 shows the parent-reported screen time use with their child (also see supplementary data). more than half of the parents (55%) reported that their child used a screen before bed and 15% indicated that there was a screen in the room where the child sleeps. parents of children in rural settings reported less screen usage before bed (p = 0.002) and fewer rural children (p = 0.005) had a screen in their bedroom compared with their urban counterparts. seventy-two percent of parents reported that their child had consistent wake up times and 69% had consistent bedtimes. for 13% of the children, sleep quality was rated as ‘poor’ by parents, with significantly more rural than urban parents reporting poor sleep quality (p = 0.042). only 13% of parents reported reading to their child every day, and in response to the question: during the past week, how many days did you or other household members read to this child? sixty parents (74%) reported an average of 4.0±1.9 days. figure 2 shows the proportion of children meeting the various components of the 24-hour movement guidelines. nearly one quarter (23%) of children met all the components of the guidelines. based on the parent questionnaire, most children met the guideline for tpa (89%), mvpa (85%) and sleep (84%). compliance with the sedentary behaviour guidelines was fig. 2. venn diagram illustrating the proportion of children meeting all of the who 24-hour movement guidelines, meeting the guidelines individually and meeting combinations of the guidelines (n=71) fig. 1. frequency of parent-reported screen use with the child original research sajsm vol. 33 no. 1 2021 6 considerably lower with 68% of parents reporting that, in the past week, their child had not spent ≤60 minutes per day engaging in sedentary screen time, and 51% of parents reported their child had not been restrained for >60 minutes at a time thus meeting these components of the sedentary behaviour guideline. associations between meeting the various guidelines and the health and developmental outcomes are reported in table 4. children who met the tpa and restrained sitting guidelines were found to have lower baz (p=0.026) but poorer working memory (p=0.016) compared to those who did not meet these guidelines. children who met all components of the guidelines had lower baz (p=0.003) and displayed better gross motor skills (p=0.032), but had lower inhibition capabilities (p=0.018) compared with those who did not. positive associations were observed between time spent stepping and gross motor skills (r=0.34, p=0.012), time spent in sedentary behaviour and shifting (r=0.27, p=0.049), and time spent seated in motorised transportation and baz (r=0.31, p=0.019). no significant associations were observed for fine motor skills, working memory and inhibitions (see table 5). two themes emerged from the focus group discussions. the first was ‘myths about the devices’ which explored the perception of caregivers and pre-school children on the use of the accelerometers. despite providing detailed explanations about the devices and inviting questions, some caregivers thought that the devices had spiritual and or political connotations. they were hesitant about future implications and table 4. comparison of baz, gross motor skills, fine motor skills, executive functions (working memory, inhibition, shifting) by meeting/not meeting individual and integrated movement behaviour guidelines tpa mvpa sst sleep duration restrained sitting all five guidelines yes (n=65) no (n=6) yes (n=62) no (n=9) yes (n=37) no (n=34) yes (n=50) no (n=21) yes (n=61) no (n=10) yes (n=17) no (n=54) baz median iqr mr -0.43 -1.58–0.58 34.37 0.75 0.35–1.85 53.67 -0.42 -1.31–0.69 35.63 0.17 -2.21–1.06 38.56 -0.55 -1.61–0.32 31.86 -0.13 -0.74–1.03 40.86 -0.39 -1.53–0.80 35.24 -0.20 -1.22–0.74 37.81 -0.43 -1.60–0.63 34.24 0.32 -0.55–1.73 46.75 -1.25 -1.84– -0.37 23.12 -0.21 -0.77–1.02 40.06 p-value 0.026* 0.691 0.078 0.632 0.076 0.003** gross motor skills median iqr mr 60.0 58.5–60.0 35.03 57.0 54.0–60.0 29.00 60.0 54.0–60.0 34.71 60.0 54.0–60.0 33.11 60.0 60.0–60.0 37.32 60.0 54.0–60.0 31.33 60.0 60.0–60.0 35.30 60.0 54.0–60.0 32.71 60.0 54.0–60.0 34.06 60.0 58.5–60.0 37.05 60.0 60.0–60.0 41.69 60.0 54.0–60.0 32.29 p-value 0.492 0.770 0.108 0.521 0.569 0.032* fine motor skills median iqr mr 40.0 30.0–55.0 33.59 42.5 40.0–56.2 43.92 40.0 30.0–55.0 35.06 35.0 30.0–52.5 30.83 40.0 31.25–50.0 34.35 40.0 25.0–55.0 34.67 40.0 30.0–50.0 32.78 45.0 32.5–55.0 38.36 40.0 30.0–55.0 33.76 42.5 35.0–55.0 38.80 37.5 30.0–45.0 30.53 40.0 30.0–55.0 35.72 p-value 0.228 0.547 0.946 0.279 0.453 0.355 working memory median iqr mr 1.00 0.00–2.00 33.15 1.00 0.00–2.00 31.50 1.00 0.00–1.92 32.06 1.33 0.33–2.17 38.83 1.00 0.00–1.92 31.83 1.00 0.00–2.00 34.45 1.00 0.00–2.00 34.24 1.00 0.00–1.33 30.00 1.00 0.00–1.67 30.65 2.00 0.75–2.41 45.95 0.67 0.00–1.67 29.32 1.00 0.00–2.00 34.30 p-value 0.851 0.309 0.572 0.402 0.016* 0.341 inhibition median iqr mr 0.60 0.47–0.75 34.66 0.46 0.30–0.77 27.33 0.59 0.46–0.72 33.60 0.70 0.31–0.82 36.94 0.57 0.39–0.71 31.62 0.62 0.48–0.76 36.76 0.58 0.46–0.71 33.01 0.62 0.43–0.81 36.33 0.59 0.42–0.73 32.79 0.63 0.48–0.92 40.90 0.51 0.30–0.64 24.35 0.63 0.47–0.81 37.28 p-value 0.395 0.650 0.282 0.524 0.225 0.018* shifting median iqr mr 7.00 1.00–9.00 33.69 2.00 0.00–9.00 26.17 5.50 0.25–9.00 33.17 4.00 1.00–9.00 31.94 7.00 1.00–9.00 33.24 4.00 0.75–9.25 32.72 5.50 0.75–10.00 33.82 4.00 1.00–9.00 31.03 5.50 1.00–9.00 32.72 4.00 1.00–11.50 34.72 8.00 0.00–9.00 33.44 4.00 1.00–9.75 32.84 p-value 0.368 0.855 0.910 0.910 0.766 0.910 *indicates significance at p<0.05; **indicates significance at p<0.0005. “yes” indicates the participants that met the guidelines and “no” indicates the participants that did not meet the guidelines. mr, mean ranks; iqr, interquartile range (presented as 25th – 75th percentile); baz, bmi-for-age z score; tpa, total physical activity; mvpa, moderate-vigorous intensity physical activity; sst, sedentary screen time. original research 7 sajsm vol. 33 no. 1 2021 wanted further assurance of their safety. caregivers also reported how children and adults were curious about the devices and were tempted to remove them so that they could explore the devices more closely. teachers were helpful in explaining the purpose of the accelerometers and reassuring caregivers. ‘i was very worried when i saw my child with that thing (accelerometry device), i had to come here and ask the teacher, that is when i felt peace in my heart.’ (participant 1) the second theme was ‘dynamics of consenting’ which reported on the cultural and contextual factors that affected consenting to the study and the use of self-report measures. the father, as the head of the family, was regarded as responsible for consenting and reporting about the child. however, at times fathers could not respond to specific questions about the child’s routine. ‘it is correct that you have invited me to this meeting, yes, i am the father but some of the information you are asking only the mother (of child) knows’. (participant 2) also, when a meeting was called, caregivers would send one person to represent the whole neighbourhood or an extended family relative; unfortunately, that person was not able to give consent for another person’s child. discussion this pilot study assessed movement behaviours in pre-school children from low-income settings in zimbabwe. we found that it is appropriate to conduct studies of this nature in zimbabwe. through conducting this research, the sunrise team has learned how best (or how better) to conduct a bigger trial and/or other research where young children and parents in lmics are required to contribute. more studies in this area will allow for population surveillance of movement behaviours and provide evidence to inform other interventions. [1] this is important in low-income countries where there are limited studies on movement behaviours in children. [4] this is the first study to examine the proportion of children meeting the who global guidelines for children under the age of five years in zimbabwe. the only other such study undertaken was by mushonga, mujuru[9], who used selfreported measures to collect data on factors associated with overweight/obesity among pre-school children. although in this study the most knowledgeable parent needed to respond to the questionnaire, and this study confirmed a possible limitation with self-reported measures through a focus group discussion. it is important to highlight this possible limitation and design ways to increase the validity and reliability of data collected in future studies. the proportion of children meeting all who global guidelines was higher than that reported among children from other lower to middle income countries (lmics). for example, in china, where 15% met all three guidelines, in guan, zhang [10] and south africa, 26% met all five guidelines [4]. noted variations in proportions could be attributed to the differences in accelerometer data collection (e.g. different types of physical activity monitors (e.g. activpal vs actigraph), and data reduction (e.g. different cut-points for light physical activity/mvpa) between studies would result in different estimates of physical activity. similarly, the above reasons can be used to explain why children in zimbabwe had a higher proportion of those who met the sleep guideline compared with china10 and south africa. [4] however, we also found that a higher proportion of children from zimbabwe met the screen time guideline compared with south africa.[4] findings confirm the results of a study done in zimbabwe by mushonga, mujuru [9] who reported that urban children spent more than three hours a day, especially on weekends, watching television or playing games. in contrast to participants in the south african sunrise study [4], most rural communities in zimbabwe do not have access to electricity, hence children in rural settings were reported to have less screen usage before bed. also, fewer rural children had a screen in their bedroom compared to the urban sample. the high number of children with access to the use of screens is worrying as research has shown that an increase in screen use is associated with obesity. [12] table 5. correlations between accelerometer measures and baz, gross motor skills, fine motor skills and executive functions (working memory, inhibition, shifting) guideline baz (n=58) gross motor skills (n=55) fine motor skills (n=55) working memory (n=52) inhibitions (n=53) shifting (n=53) r p-value r p-value r p-value r p-value r p-value r p-value total stepping (min/day) -0.07 0.589 0.34 0.012* -0.09 0.496 0.09 0.550 0.13 0.372 0.12 0.404 total standing (min/day) -0.04 0.749 -0.17 0.226 -0.11 0.411 0.25 0.080 0.10 0.500 -0.15 0.283 total sitting (min/day) 0.24 0.070 -0.18 0.188 0.15 0.263 -0.08 0.562 -0.218 0.117 0.110 0.432 lying (min/day) -0.11 0.431 -0.18 0.193 0.22 0.113 -0.11 0.431 0.03 0.851 0.27 0.049* total sb (min/day) -0.04 0.767 -0.07 0.602 0.09 0.498 0.12 0.410 -0.17 0.227 -0.01 0.923 restricted sitting (min/day) 0.31 0.019* 0.04 0.796 -0.03 0.857 -0.25 0.073 -0.01 0.954 0.27 0.055 sleep (min/day) -0.06 0.633 0.12 0.388 -0.19 0.160 -0.15 0.278 0.05 0.738 -0.06 0.651 *indicates significance at p<0.01. baz, bmi-for-age z score; sb, sedentary behaviours; r, spearman’s correlation coefficients. original research sajsm vol. 33 no. 1 2021 8 this study confirms previous findings that there is a significant proportion of children who are overweight and obese in zimbabwe. [9] bmi and height were significantly lower in the rural population compared with the urban population. further research on the growth and health of children against reports of undernutrition and stunting growth [8] in children in rural zimbabwe might be required. most children who participated in this study performed well in the gross motor domain. the new ecd curriculum in zimbabwe emphasises learning through play, and most preschools have a playground with swings and a specific time is aside for playing outside as part of the daily routines for children. [8] however, a comparison of rural vs urban children showed that rural children had a higher total stepping time than urban children. limited play spaces coupled with readily accessible screen gadgets (for playing games) in urban areas could have predisposed urban children to having a lower total stepping time compared to rural children. [9] the strengths of this study include the use of wellestablished measures for this age group in low-income zimbabwean settings, and the benefits of the collective expertise and experience of the sunrise global leadership group to inform the study design. the study also provided insights into aspects to consider when undertaking future studies on 24hr-movement behaviours of children from low resourced settings. more time should be invested in explaining the study to caregivers and the children as compliance to wearing the accelerometer is important in the reliability of the results. [10] although children aged four-six years are very active and exploratory in nature, the tegaderm used to fix the accelerometer did not fall off. however, some children tried to remove the device out of curiosity in order to explore it further. limitations the main limitation of this pilot study was the small sample size and the study setting which was limited to one province in zimbabwe. thus findings cannot be generalised to other settings. this study used a cross-sectional design which precludes establishing causality. conclusion this pilot study contributes important initial findings on 24hour movement behaviours of zimbabwean pre-school children, and highlights that these behaviours require further attention in this age group. this is particularly important considering the growing risk of child obesity and high levels of screen time. understanding how movement behaviours are associated with key outcomes, such as gross and fine motor skills as well as executive function in early childhood, is vital for setting children on their best trajectories for health and early learning. the study also provided insights into aspects to consider when undertaking future studies in this area. conflict of interest and source of funding: the authors declare no conflict of interest. research reported in this publication was supported by the fogarty international center (office of the director, national institutes of health (od), national institute of nursing research (ninr), national institute of mental health (nimh), national institute of dental & craniofacial research (nidcr), national institute of neurological disorders and stroke (ninds), national heart, lung, and blood institute (nhlbi), fogarty international center (fic)) of the national institutes of health under award number d43 tw010137. the content is solely the responsibility of the authors and does not necessarily represent the official views of the national institutes of health. acknowledgements: the authors would like to thank local field workers, gloria rusenga, darrel ngove and tanyaradzwa masanga for their assistance with recruitment and data collection, and the ministry of primary and secondary education office for facilitating community entry. the authors are also grateful to the pre-schools, teachers, parents/caregivers and children for their cooperation and participation. author contributions: nm was the lead country researcher, fm and pg supervised the research process in zimbabwe. mc and tc collected and entered the data. ao, cd, pc, were involved in conceptualisation of the research and supervision at international level. kk, and khc developed the tools and analysed the data. all the authors contributed to the research process and writing of the manuscript. references 1. willumsen j, bull f. development of who guidelines on physical activity, sedentary behaviour, and sleep for children less than 5 years of age. j phys act health 2020;17(1):96-100 [doi: 10.1123/jpah.2019-0457] [pmid: 31877559] 2. world health organization. report of the commission on ending childhood obesity. geneva: world health organization, 2016. isbn 978 92 4 151006 6. available from: https://apps.who.int/iris/bitstream/handle/10665/259349/who -nmh-pnd-echo-17.1-eng.pdf. (accessed 10 september 2018) 3. world health organization. guidelines on physical activity, sedentary behaviour and sleep for children under 5 years of age. geneva: world health organization; 2019. available from: https://apps.who.int/iris/handle/10665/311664. (accessed 23 october2020) 4. draper ce, tomaz sa, biersteker l, et al. the south african 24hour movement guidelines for birth to 5 years: an integration of physical activity, sitting behavior, screen time, and sleep. j phys act health. 2020;17(1):109-119 [doi: 10.1123/jpah.20190187] [pmid: 31877557] 5. tremblay ms, leblanc ag, carson v, et al. canadian physical activity guidelines for the early years (aged 0–4 years). appl physiol nutr metab 2012;37(2):345-356. [doi: 10.1139/h2012018] [ pmid: 22448608] 6. okely ad, ghersi d, hesketh kd, et al. a collaborative approach to adopting/adapting guidelines the australian 24hour movement guidelines for the early years (birth to 5 years): an integration of physical activity, sedentary behavior, and sleep. bmc public health 2017;17(suppl 5):869 [doi: 10.1186/s12889-017-4867-6] [ pmid: 29219094]. 7. muthuri sk, wachira l-jm, leblanc ag, et al. temporal trends and correlates of physical activity, sedentary behavior, and physical fitness among school-aged children in sub-saharan https://apps.who.int/iris/bitstream/handle/10665/259349/who-nmh-pnd-echo-17.1-eng.pdf https://apps.who.int/iris/bitstream/handle/10665/259349/who-nmh-pnd-echo-17.1-eng.pdf https://apps.who.int/iris/handle/10665/311664 original research 9 sajsm vol. 33 no. 1 2021 africa: a systematic review. int j environ res public health 2014;11(3):3327-3359 [doi:10.3390/ijerph110303327] [pmid: 24658411]. 8. manyanga t, munambah ne, mahachi cb, et al. results from zimbabwe’s 2018 report card on physical activity for children and youth. j phys act health 2018;15(s2):s433-s435 [doi: 10.1123/jpah.2018-0520] [pmid: 30475101] 9. mushonga ng, mujuru ha, nyanga lk, et al. factors associated with overweight/obesity among preschool children aged 3-5years. journal of applied science in southern africa. 2014;20(2) 10. guan h, zhang z, wang b, et al.. proportion of kindergarten children meeting the who guidelines on physical activity, sedentary behaviour and sleep and associations with adiposity in urban beijing. bmc pediatr 2020;20(70) [doi: 10.1186/s12887-020-1969-6][pmid: 32061263] 11. zimbabwe. ministry of primary and secondary education. 2018 primary and secondary education statistics report 2018. harare: mopse, 2019. available from: http://www.mopse.co.zw/sites/default/files/public/downloads /annual education statistics report 2018.pdf 12. carson v, lee e-y, hewitt l, et al. systematic review of the relationships between physical activity and health indicators in the early years (0-4 years). bmc public health 2017;17(suppl 5):854 [doi: 10.1186/s12889-017-4860-0] 13. squires j, bricker dd, twombly e. ages & stages questionnaires: a parent-completed child monitoring system. baltimore, md. paul h. brookes. 2009 14. howard sj, melhuish e. an early years toolbox for assessing early executive function, language, self-regulation, and social development: validity, reliability, and preliminary norms. j psychoeduc assess 2017;35(3):255-275 [doi: 10.1177/0734282916633009] [pmid: 28503022] 15. braun v, clarke v. one size fits all? what counts as quality practice in (reflexive) thematic analysis? qual res psychol 2021; 18 (3): 328-352 [doi: 10.1080/14780887.2020.1769238] http://www.mopse.co.zw/sites/default/files/public/downloads/annual%20education%20statistics%20report%202018.pdf http://www.mopse.co.zw/sites/default/files/public/downloads/annual%20education%20statistics%20report%202018.pdf sportsmed_june04 introduction in 1994 legislation was passed by the united states food and drug administration (fda) in which the government control of supplement production was relaxed. this dietary supplement and health education act resulted in several androgenic steroids, e.g. androstenedione and dehydroepiandrosterone (dhea) becoming legal and available for purchase over the counter without a prescription. this sudden growth of dietary supplement production has led to some questionable quality control manufacturing practices, resulting in contamination of nutritional supplements, which may be a possible explanation for the apparent increase in the number of positive doping tests amongst high profile athletes. nutritional supplement use is also very popular in south africa and the turnover of the industry is approximately r1.5 billion a year (health products association of south africa survey 1998 2000). nutritional supplements include vitamins, minerals, herbal powders, carbohydrates and protein powders. vitamins and minerals are not prohibited substances in sport, but may be combined with substances that are prohibited. there are a wide variety of nutritional substances specifically designed for athletes. athletes assume that these supplements do not contain prohibited substances because they are readily available without prescriptions and are sold legally as supplements. the reasons why athletes use supplements include performance enhancement, faster recovery during training, manipulation of body composition and reduction in illness or infection risks (maughan r. the scope of nutritional supplement use in sport. health and doping risks of nutritional supplements and social drugs. cologne, germany: international symposium, 18 july 2002.) recent studies have shown that non-hormonal nutritional supplements such as vitamins, minerals and amino acids may contain banned substances not listed on the label.4 results from an international olympic committee (ioc) study5 on nutritional supplements (13 countries excluding south africa) showed that 94 (14.8%) of 634 samples contained prohormones not listed on the label. both catlin et al.1 and kamber et al.6 analysed nutritional supplements and found hormone contaminants not listed on the labels. this may explain the recent increase in positive doping cases. nutritional supplement manufacturing is not subject to the same stringent regulatory inspection and licensing requirements as is the case with medicines (schröder u. sports medicine vol 16 no.2 2004 3 original research article inadvertent doping through nutritional supplements is a reality p j van der merwe (phd) e grobbelaar (msc chem) south african doping control laboratory, department of pharmacology, university of the free state, bloemfontein correspondence: p j van der merwe south african doping control laboratory department of pharmacology university of the free state po box 339 bloemfontein 9300 tel: 051-401 3182 fax: 051-444 1523 e-mail: gnfmpvdm.md@mail.uovs.ac.za abstract objective. inadvertent doping through the use of nutritional supplements is a potentially important cause of the increase in positive drug tests involving high-profile olympic athletes. the aim of this study was to screen over-the-counter nutritional supplements for the presence of steroid or stimulant compounds banned by the international olympic committee (ioc) and the world anti-doping agency (wada). method. thirty different nutritional supplements from 14 different manufacturers were bought at shops in bloemfontein, south africa and analysed for testosterone and nandrolone prohormones, various ephedrines and caffeine. results. eighteen (60%) of the 30 supplements contained no prohibited substances. of the 12 (40%) positive supplements, 8 (66.7%) contained prohormones and 4 (33.3%) contained stimulants. six supplements contained prohormones, which were listed on the labels, while 2 contained prohormones not listed on the labels. the stimulants were listed on the labels as ma huang, guarana and kola extracts and all contained a mixture of ephedrines and caffeine. conclusion. the results showed that approximately 7% of supplements tested may be mislabelled or contaminated with banned substances and that inadvertent doping through nutritional supplement use is a reality for athletes. the sporting community should therefore be aware that supplements might contain anabolic androgenic steroids and stimulants that are not declared on the labels. 4 sports medicine vol 16 no.2 2004 health effects of nutritional supplements. health and doping risks of nutritional supplements and social drugs. cologne, germany: international symposium, 18 july 2002.) the result is inaccurate product labelling, batch composition differences and possible contamination with prohormones, which are prohibited substances in sport. objective the aim of this study was to screen over-the-counter nutritional supplements for steroids (testosterone, nandrolone and prohormones) and stimulant compounds in an attempt to define the extent of supplement contamination or mislabelling. method thirty different nutritional supplements from 14 different manufacturers were bought at random at shops in bloemfontein and analysed for testosterone, nandrolone, their prohormones, various ephedrines and caffeine. the prohormones were extracted as follows. approximately 1 g of supplement was extracted with 5 ml methanol. the methanolic layer was evaporated and made basic with 5 ml potassium hydroxide (0.1 m, ph > 12). re-extraction with 5 ml n-pentane was followed by another methanol extraction, which was evaporated. derivatisation with 80 µl mstfa/nh4i/ethanethiol (1000:2:3 v/w/v) for 30 minutes at 60°c followed. the sample was diluted with 140 µl toluene and analysed using an agilent (palo alto, ca, usa) gas chromatograph (6890n series) interfaced with a mass selective detector (5973n series). the quantity of dhea, 4-androstenedione and 19-nor-4androstenedione for supplements 19 and 20 were determined by analysing 5 capsules from each container. the ephedrines8 and caffeine2 in the samples were extracted and quantified according to standard laboratory procedures. results eighteen (60%) of the 30 supplements contained no prohibited substances. of the 12 (40%) positive supplements, 8 (66.7%) contained prohormones and 4 (33.3%) contained stimulants. two (6.7%) of the supplements were contaminated or mislabelled. the prohormones and stimulants found in the nutritional supplements are listed in tables i and ii, respectively. stimulants were only listed as herbal extracts as indicated in table ii. four supplements (6, 7, 14 and 24) contained the prohormone dhea which was listed on the label in each case. supplement 22 contained dhea and 4-androstenedione with both substances listed on the label. supplement 5 contained the banned substance 19-nor-4-androstenedione, which was listed on the label. supplement 19 only listed branched chain amino acids on the label but small amounts of dhea and 4-androstenedione were found in the capsules. no indication of the presence of these two compounds could be found on the label. supplement 20 had β-hydroxyβ-methylbuturate (hmb) listed on the label but small amounts of 4-androstenedione and 19-nor-4-androstenedione (both substances not listed on the label) were found. a second container of supplement 19 (19b) and supplement 20 (20b) were obtained from the same shop and analysed. supplement 19b also tested positive for dhea and 4androstenedione but in different quantities than in 19a. no 4androstenedione or 19-nor-4-androstenedione was detected in the 20b. table i. prohormones found in nutritional supplements supplement µg/capsule no listed on label found mean (range) 5 19-nor-4-androstenedione 19-nor-4-androstenedione 6 dhea dhea pregnenolone 7 dhea dhea 14 dhea dhea 19a* branched-chain amino acids dhea 0.76 (0.67 0.85) 4-androstenedione 1.64 (1.35 1.94) 19b* branched-chain amino acids dhea 14.00 (7.40 17.80) 4-androstenedione 8.21 (4.10 12.90) 20a* hmb 4-androstenedione 0.16 (0.10 0.35) 19-nor-4-androstenedione 16.5 (8.40 31.80) 20b* hmb no banned substance 22 dhea dhea 4-androstenedione 4-androstenedione tribulus terristris 24 dhea dhea *five capsules per container were analysed. dhea = dehydroepiandrosterone; hmb = β-hydroxy β-methylbutyrate. sports medicine vol 16 no.2 2004 5 discussion six supplements contained prohormones of testosterone (dhea and 4-androstenedione) and nandrolone (19-nor-4androstenedione) as listed on the labels. careful reading of the label and obtaining information on whether the supplement is on the banned list of the ioc/world anti-doping agency (wada), should alert the athlete to avoid these supplements and therefore reduce the chances of a positive dope test. the problem lies with supplements where there is no indication on the label that they contain banned substances. supplement 19 listed branched chain amino acids on the label, with no indication that it contained banned substances. yet when the capsules were tested, low amounts of dhea and 4-androstenedione were found. supplement 20 listed hmb on the label, but when it was tested low amounts of 4-androstenedione and 19-nor-4-androstenedione were found. kamber et al.6 analysed 75 different nutritional supplements and found that more than 9% contained hormonal substances not listed on the labels, a finding similar to this study. there was a significant difference in the quantity of dhea and 4-androstenedione found in the two supplement containers 19a and 19b (18-fold for dhea and 5-fold for 4androstenedione). there was also a wide range of concentration in individual capsules of the 2 supplement products (especially in container 19b). the same applies for the quantity of 4-androstenedione and 19-nor-4-androstenedione in supplement 20a. this clearly shows that there was no quality control in the manufacturing process of supplements 19 and 20. catlin et al.1 analysed androstenedione capsules (listed on the label) and found that they also contained 19-nor-4-androstenedione (not listed on the label) in the range 4 18 µg/capsule.1 both in our study and that of catlin et al.1 the concentration of non-listed hormonal substances was in the µg/capsule range. de cock et al.3 found much higher concentrations of 4-androstenedione and 19nor-4-androstenedione (0.7 mg and 4.8 mg/capsule respectively) in a nutritional supplement. these hormonal products were not listed on the label. the stimulants were listed on the labels as ma huang, guarana and kola extracts (table ii). all 4 supplements contained a mixture of ephedrines and caffeine. the supplements contained ephedrines and caffeine in varying concentrations, with the ephedrine concentrations corresponding to those of cold and flu drugs (5 10 mg). the recorded caffeine concentrations were lower than those of a cup of coffee (90 150 mg caffeine). when ma huang extract or herbal tea blend was listed on the label different ephedrines were detected in the supplements in different concentrations, as illustrated in table ii. larimore and o'mathúna7 found that ephedra products varied in ephedra alkaloid content, a finding similar to that in our study. the problem is that when ma huang extract is listed on the label as an ingredient of the supplement it does not warn the athlete that it contains banned substances. supplement 2 listed herbal tea blend as one of the ingredients, with no indication that it contained ephedra. the fine print on the label of this supplement warns professional athletes not to use this product, but no clear reason for this is given. inadvertent doping can occur in three ways: (i) prohibited substances are declared on the label but the athlete is not aware that it is a banned substance; (ii) prohibited substances are declared on the label, but under different names which the athlete is unfamiliar with (e.g. ephedrine is listed as ma huang, chinese ephedra, epitonin, sida cordifolia, or ephedra, while caffeine is listed as guarana, kola or gotu kola); and (iii) prohibited substances are not declared on the label — these substances could have been added deliberately, or could be the result of contamination during or after synthesis, capsulation, or packaging. the ioc and wada have a clause of strict liability stating that the athlete is ultimately responsible for what is found in his/her body fluids irrespective of its origin. therefore, the risk of an inadvertent positive test after using nutritional supplements remains the athlete's responsibility. supplements 5, 6, 7, 14, 22, and 24 clearly stated on the label that they contained banned substances, in which case ignorance on the part of the athlete is no defence. supplements 19 and 20 may fall into two different categories. the first category is what can be called 'contamination' — during the manufacturing process (using the same machines to produce non-hormonal and hormonal supplements) the product is unintentionally mixed with a very small amount of banned substance. clearly there was no intent on the side of the supplement company, just a lack of quality control. the second category is 'mislabelling' whereby the supplement company intentionally adds small amounts of table ii. stimulants found in nutritional supplements supplement listed on label found mg/capsule 2 gotu kola caffeine 30.0 herbal tea blend ephedrine 7.3 pseudoephedrine 1.1 methylephedrine 0.3 3 kola extract caffeine 66.4 ma huang extract ephedrine 1.5 pseudoephedrine 2.4 methylephedrine 6.8 18 guarana extract caffeine 39.0 ma huang extract ephedrine 3.2 pseudoephedrine 0.3 methylephedrine 0.1 21 guarana extract caffeine 63.7 ma huang extract ephedrine 6.6 pseudoephedrine 0.9 methylephedrine 0.3 performance-enhancing steroid or stimulant compound to boost the effectiveness of a particular product. on its own the supplement may show no performance improvement. the practice of the supplement company in this instance is unethical. although these two categories are different, the athlete still has to accept responsibility for a positive dope test as it is very difficult to prove the two scenarios from the side of the manufacturing company and what supplement was actually used by the athlete. conclusion the results show that inadvertent doping through nutritional supplement use is a reality for athletes. the sporting community should therefore be aware that supplements might contain anabolic androgenic steroids and stimulants that are not declared on the labels. references 1. catlin dh, leder bz, ahrens b, et al. trace contamination of over-thecounter androstenedione and positive urine test results for nandrolone metabolite. jama 2000; 284: 2618-21. 2. cawley at, trout gj, kazlauskas r. quantitation of urinary caffeine by gc/ms using 13c caffeine as internal standard. in: schänzer w, geyer h, gotzman a, mareck-engelke u, eds. proceedings of the 19th cologne workshop on dope analysis. cologne: sport und buch strausse, 2001: 229-32. 3. de cock kjs, delbeke ft, van eenoo p, desmet n, roels k, de backer p. detection and determination of anabolic steroids in nutritional supplements. j pharm biomed anal 2002; 25: 843-52. 4. geyer h, henze mk, mareck-engelke u, wagner a, schrader y, schänzer w. analysis of ‘non-hormonal’ nutritional supplements for prohormones. in: schänzer w, geyer h, gotzman a, mareck-engelke u, eds. proceedings of the 19th cologne workshop on dope analysis. cologne: sport und buch strausse, 2001:63-72. 5. geyer h, parr mk, mareck u, reinhart u, schrader y, schänzer w. analysis of non-hormonal nutritional supplements for anabolic androgenic steroids results of the international ioc study. in: schänzer w, geyer h, gotzman a, mareck-engelke u, eds. proceedings of the 20th cologne workshop on dope analysis. cologne: sport und buch strausse, 2002: 83-6. 6. kamber m, baume n, saugy m, rivier l. nutritional supplements as a source for positive doping cases. international journal of sport nutrition and exercise metabolism 2001; 11: 258-63. 7. larimore wl, o'mathúna. quality assessment programs for dietary supplements. ann pharmacother 2003; 37: 893-898. 8. van der merwe pj, brown lw, hendrikz se. simultaneous quantification of ephedrines in urine by high-performance liquid chromatography. j chromatogr b biomed sci appl 1994; 661: 357-61. invited comment by shelly meltzer, board member of the sa institute for drug free sport, and dietician, sport science institute of south africa, cape town. despite similar studies having been done overseas,1-3 the supplement industry (unlike food and drugs) is still uncontrolled and poorly regulated. there is generally no control on the production (i.e. no standard manufacturing practice), importation, distribution and marketing of supplements; there is no control on the exact composition of these products and there is no system to ensure that the products are safe and effective. the above study by van der merwe and grobbelaar is therefore very relevant and will hopefully bring home the message that supplements that are locally available are indeed risky and that our athletes have no guarantee that they will not be ingesting contaminants, banned substances or by-products from the synthesis of pro-hormones or other banned substances when using supplements. moreover, in accordance with international rules, athletes remain responsible for what is found in their body fluids, irrespective of the origin. this surely raises ethical questions for professionals who advise athletes to take these substances, knowing that should athletes test positive for banned substances they may be ineligible to compete, thus ruining their career. perhaps it is also important to clarify a few other misconceptions regarding sports supplements. here are the facts: 1. sports supplements are not any safer than vitamins and minerals. 2. supplements marketed as ‘natural’ are not necessarily acceptable. even herbals may have side-effects. 3. presently there is no way to recommend with certainty that one particular brand is safer than another. although some international institutions have introduced certification programmes for supplements there are still loopholes. athletes are therefore advised to request the supplier of any supplement to provide a quality control certificate. this certificate should demonstrate that the product has been tested at an independent ioc-accredited laboratory and has been shown to be free of prohibited substances. furthermore, the certificate should have legally binding documentation listing all the contents of all the different products that the company produces and a statement that the company accepts full liability should an athlete use the supplement and fail a drug test. this guarantee document should: (i) be on a company letterhead; (ii) be signed by management and dated; (iii) include contact details for the person responsible for issuing the guarantee; (iv) address the athlete directly by name, and not be addressed generally, e.g. ‘to whom it may concern’. 4. even if the product label says ‘ioc permitted’ this does not mean it is safe to use. the ioc does not endorse any nutritional supplements. 5. the usa food and drug administration (fda) has notified manufacturers of its intent to ban the sale of dietary supplements containing ephedrine alkaloids. however, there may still be athletes with stocks of supplements that contain ephedrine which may be listed on the label under various pseudonyms (refer to the study) or in some products may not have been declared. products do not always contain what is listed on the label. batch-to-batch differences in nutrients may vary considerably in one brand and there have been reports of supplements containing dangerously high (e.g. niacin) and low (e.g. folic acid) levels of nutrients. you may even get more than what you have paid for. the fda reports that upon inspection supplements have been found to contain aflatoxin, mycotoxin, lead, salmonella and even glass (http://www.fda.gov/dockets/ecomments.). 6. even small amounts of a contaminant (e.g. 0.02% nandrolone in a supplement) may cause a positive test. 6 sports medicine vol 16 no.2 2004 7. although caffeine has recently been removed from the banned ioc/wada lists it is still advisable to be familiar with the wide range of caffeine-containing foods, beverages (e.g. energy drinks, sports drinks, tea and coffee), sports gels and drugs to avoid any undesirable side-effects which may negatively affect performance. 8. products often make false claims. a practical guide describing the efficacy and use of nutritional supplements in sport has been compiled for sa rugby and is available from the south african institute of drug free sport (www.drugfreesport.org.za) references 1. catlin dh, leder bz, ahrens b, et al. trace contamination of over-thecounter androstenedione and positive urine test results for nandrolone metabolite. jama 2000, 284:2618-21. 2. geyer h, mareck-engelke u, reinhart u, schänzer w. positive dope control cases with norandrosterone after application of contaminated nutritional supplements. d zeitschr sportmed 2000, 51: 378-82. 3. kamber m, baume n, saugy m, rivier l. nutritional supplements as a source for positive doping cases? international journal of sport nutrition and exercise metabolism 2001; 11: 258-63. sports medicine vol 16 no.2 2004 7 2 sajsm vol. 28 no. 1 2016 original research changes in markers of fatigue following a competitive match in elite academy rugby union players g roe,1,2 msc; k till,1,2 phd; j darrall-jones,1,2 msc; p phibbs,1,2 msc; j weakley,1,2 msc; d read,1,2 msc; b jones,1,2 phd 1 research institute for sport, physical activity and leisure, leeds beckett university, leeds, west yorkshire, united kingdom 2 yorkshire carnegie rugby club, headingley carnegie stadium, st. michael’s lane, leeds, west yorkshire, united kingdom. corresponding author: g roe (g.roe@leedsbeckett.ac.uk) background: post-match fatigue has yet to be investigated in academy rugby union players. objectives: to determine the magnitude of change in upper (plyometric push-up (pp) flight-time) and lower-body (countermovement jump (cmj) mean power) neuromuscular function (nmf), whole blood creatine kinase (ck) and perception of well-being following a competitive match in academy rugby union players. methods: fourteen academy rugby union players participated in the study. measures were taken 2 h pre-match (baseline) and immediately post-match. further testing was also undertaken at 24-, 48and 72 h respectively post-match. changes in measures from baseline were determined using magnitude-based inferences. results: decreases in cmj mean power were likely substantial immediately (-5.5±3.3%) post-match, very likely at 24 h (-7±3.9), likely at 48 h (-5.8±5.4), while likely trivial at 72 h (-0.8±3.8) post-match. pp flight-time was very likely reduced immediately (-15.3±7.3%) and 24 h (-11.5±5.7%) post-match, while possibly increased at 48 h (3.5±6.0%) and likely trivial at 72 h (-0.9±5.4%) post-match. decreases in perception of well-being were almost certainly substantial at 24 h (-24.0±4.3%), very likely at 48 h (-8.3±5.9%), and likely substantial at 72 h (-3.6±3.7%) post-match. increases in ck were almost certainly substantial immediately (138.5±33%), 24 h (326±78%) and 48 h (176±62%) post-match, while very likely substantial at 72 h (57±35%) post-match. conclusion: these findings demonstrate the transient and multidimensional nature of post-match fatigue in academy rugby union players. furthermore, the results demonstrate the individual nature of recovery, with many players demonstrating different recovery profiles from the group average. keywords: collision sport, monitoring, sports injuries s afr j sports med 2016;28(1):2-5. doi:10.17159/2078-516x/2016/v28i1a418 rugby union is a collision sport that involves intermittent high-intensity activities, including sprinting, rucking, mauling, scrummaging and tackling, that are interspersed with periods of jogging, walking and standing.[1] observations following one,[2,3] two[4] and four[5] competitive matches suggest that the highintensity activities and impacts sustained during rugby union match play result in acute post-match fatigue that may last for several days following competition. fatigue may manifest as alterations in mood,[3] immune function[2] and hormone levels,[3] reductions in neuromuscular function (nmf)[3] and elevations in markers of muscle damage (e.g. an increase in creatine kinase concentration ck).[2,5] the authors’ understanding of post-match fatigue in rugby union players has been derived primarily from studies involving senior athletes. to date, no study has investigated post-match fatigue in academy rugby union players. the literature examining postmatch fatigue in other junior collision sport athletes is also far less voluminous than in senior players. a likely substantial reduction in lower-body nmf, as measured by countermovement jump (cmj) peak power, has been observed in elite under-18 australian rules football players for up to 24 h following an intra-club preseason match[6] while in sub-elite youth rugby league players, reductions were reported as likely substantial immediately, and possibly substantial at 24 h and 48 h following two competitive matches.[7] upper-body nmf, as measured by plyometric push-up peak power, has also shown very likely and likely substantial decreases at 24 h and 48 h respectively following two competitive sub-elite youth rugby league matches.[7] furthermore, ck has been observed to peak at 24 h post-match and remain elevated at 48 h in sub-elite junior rugby league players.[7] however, no study has examined ck responses to match-play in this population beyond 48 h post-match. understanding the time-course of recovery following a competitive match is extremely important. such knowledge can be applied to ensure that players have adequately recovered prior to undertaking subsequent training or competing in a later game. failure to recover may lead to fatigue accumulation and result in injury, illness and poor performance.[2,8] research in academy rugby union players provides scientific evidence with which to inform recovery and training practices in the post-match microcycle in this group of athletes. therefore the purpose of the current study was to investigate the magnitude of change, and the time-course of recovery in markers of nmf, muscle damage and perception of well-being following a competitive match in academy rugby union players. methods subjects fourteen players (age 17.4±0.8 years; height 182.7±7.6 cm; body mass 86.2±11.6 kg) were recruited from a professional rugby union academy. players were excluded if they had an injury that prevented them from participating in the testing or were involved in less than 75% of the total game time. the university’s ethics board granted approval and written informed consent was acquired from all subjects along with parental consent. procedures and design a within-group repeated measures design was used to examine the magnitude of change in markers of nmf, muscle damage (whole blood ck) and perception of well-being following a competitive match between academy rugby union players. lower-body nmf was measured using a countermovement jump (cmj), while upperbody nmf was measured using a plyometric push-up. the extent of muscle damage was examined by measuring changes in plasma ck and perception of well-being was quantified by means of a questionnaire. measures of cmj, plyometric push-up, plasma ck and perception of well-being were taken two hours pre-match (baseline) mailto:g.roe@leedsbeckett.ac.uk http://dx.doi.org/10.17159/2078-516x/2016/v28i1a418 sajsm vol. 28 no. 1 2016 3 original research and immediately post-match. further testing was also undertaken at 24 h, 48 h and 72 h post-match at the same time of day as baseline measures to avoid diurnal effects on performance. during the testing period, players did not engage in any training or strenuous activity in the days following the match. players were advised on nutritional intake but no recovery protocol was undertaken. neuromuscular function lower-body nmf was measured using mean power calculated from a cmj, while upper-body nmf was measured using flight-time calculated from a plyometric push-up. both of these measures have previously been proven reliable in this population (typical error = 3.1% and 4.2% respectively).[9] the cmj and plyometric push-up were performed on a portable force plate (400 series performance plate, fitness technology, adelaide, australia) that was attached to a laptop with software (ballistic measurement system, fitness technology, adelaide, australia) that measured ground reaction forces at 600 hz. a standardised two-minute warm-up consisting of dynamic stretching was performed prior to the performance tests (walking lunges, squats, heel flicks, high knees, skipping, leg swings and three practice submaximal cmj and plyometric pushups). following the warm-up, players performed two maximal cmj followed by two maximal plyometric push-ups with a one-minute rest between each effort.[9] for the cmj, players began standing on the force platform with knees extended and feet in a position of their choice. players were instructed to keep their hands on their hips and jump as a high as possible. the depth of the countermovement was at the discretion of the subject.[9] for the plyometric push-up, players began with their elbows extended and hands on the force platform in a position of their choice. players were instructed to perform a push-up as quickly as possible ensuring that their hands left the platform.[7] perception of well-being a six-item questionnaire was adapted from mclean et al.[10] to rate the following: sleep, fatigue, muscle soreness (upperand lowerbody), stress and mood on a five-point likert scale. each item was rated from one to five in one score increments and overall well-being was assessed by adding up all six scores. reliability of this method has previously been reported (cv = 7.1%).[9] the questionnaire was administered prior to any other testing being undertaken.[10] subjects completed the questionnaire on their own in order to prevent any influence from other players.[11] creatine kinase whole blood samples were collected from the non-dominant hand, middle fingertip of each subject. approximately 30 μl of whole capillary blood was collected using a plastic capillary tube (microsafe®, safe-tec, numbrecht, ivyland, usa) and immediately analysed using reflectance photometry (refletron® plus, boehringer manheim, germany). prior to each session, the machine was calibrated using a standardised ck strip to ensure that the machine was analysing correctly. the reliability of this method has previously been reported (cv = 26.1%).[9] match demands external match loads were assessed using gps and accelerometer technology (optimeye s5, catapult innovations, melbourne, australia). based on individual maximum velocities established three weeks prior to the match, locomotive demands were classified for each player as: walking and standing (<20% vmax), jogging (20-50% vmax), striding (51-80% vmax), sprinting (81-95% vmax) and maximum sprinting (96-100% vmax)[1]. however, as little distance was covered at maximum sprinting speed (1.43±4.01 m), the sprinting and maximum sprinting categories were aggregated to form one sprinting category (81-100% vmax). internal load was established using the session rating of perceived exertion method (srpe)[12] within 15-30 minutes of the match on a modified borg scale. statistical analysis preand post-match nmf and ck were log transformed to reduce bias as a result of non-uniformity error. perceptual data was analysed in its raw form. data were all analysed for practical significance using magnitude-based inferences.[13] the threshold for a change to be considered practically important (the smallest worthwhile change; swc) was set at 0.2 x between subject standard deviation (sd), based on cohen’s d effect size (es) principle. the probability that the magnitude of change was greater than the swc was rated as <0.5%, almost certainly not; 0.5-5%, very unlikely; 5-25%, unlikely; 25-75%, possibly; 75-95%, likely; 95-99.5%, very likely; >99.5%, almost certainly.[13] where the 90% confidence interval (ci) crossed both the upper and lower boundaries of the swc (es±0.2), the magnitude of change was described as unclear.[13] results the duration of the match was 73:37 minutes. the first and second halves lasted 36:30 minutes and 37:07 minutes, respectively. the average match load (rate of perceived exertion (rpe) x time)) was 334±121 arbitrary units (au). players covered 4691±878 m during the match with an average of 74±6 m.min-1. of the total distance, 1771±436 m was covered walking / standing, 2215±461 m jogging, 663±238 m striding and 41±40 m sprinting. average player loadtm was 451±102 and player loadtm slow was 187±47. lower-body neuromuscular function decreases in cmj mean power were likely substantial immediately (-5.5±3.3%) post-match, very likely at 24 h (-7.0±3.9), likely at 48 h (-5.8±5.4), while likely trivial at 72 h (-0.8±3.8) post-match (figure 1a). upper-body neuromuscular function reductions in plyometric push-up flight-time were very likely substantial immediately (-15.3±7.3%) and 24 h (-11.5±5.7%) postmatch, while there was a possible increase at 48 h (3.5±6%) post-match and trivial changes at 72 h (-0.9±5.4%) post-match (figure 1b). perception of well-being decreases in perception of well-being were almost certainly substantial at 24 h (-24±4.3%), very likely at 48 h (-8.3±5.9%), and likely at 72 h (-3.6±3.7%) post-match (figure 1c). 4 sajsm vol. 28 no. 1 2016 original research creatine kinase increases in ck were almost certainly substantial immediately (138.5±33.1%), 24 h (326±77.6%) and 48 h (176.4±62.4%) postmatch, while very likely substantial at 72 h (56.7±34.5%) post-match (figure 1d). fig. 1. percentage changes in cmj mean power (a), plyometric push-up flight-time (b), well-being (c) and whole blood creatine kinase concentration (d). data are percentage change with dotted and continuous lines representing individual changes and group mean changes with 90% confidence interval bars respectively, and the shaded area representing the smallest worthwhile change as a percentage. probabilities of a decrease / trivial / increase values; increase ↑ decrease ↓ trivial -. discussion the present study demonstrates the time-course of recovery in markers of fatigue following a competitive match in academy rugby union players. reductions in lower-body neuromuscular function were likely to very likely substantial for up to 48 h post-match, but likely trivial by 72 h post-match. similar changes have been observed in cmj peak power in senior players for up to 36 h following a competitive match.[3] comparable findings have also been reported in other junior collision-sport athletes. for example, wehbe et al.[6] noted very likely substantial reductions in cmj mean power for up to 24 h in under-18 australian rules football players following an intra-club preseason match, although changes were unclear beyond this point. johnston and colleagues[7] also observed likely substantial reductions in peak power immediately post-match and possible reductions at 24and 48 h following two competitive matches in subelite youth rugby league players. the post-match transient reductions in nmf may be the result of central fatigue, resulting in a reduction in voluntary muscle activation.[14] furthermore, muscle damage from repeated stretchshortening cycle actions that occur during high-intensity running,[5] and also from the blunt trauma to the lower-limb musculature that occurs during collisions,[11] may have further contributed to the reduction in nmf. in contrast, upper-body nmf in the present study was very likely reduced for 24 h post-match, with substantial reductions being unlikely beyond this point. this reduction may be attributed to the blunt trauma sustained during physical contact, which has a substantial effect on upper-body nmf.[7] changes in upper-body nmf have not currently been investigated in senior rugby union players. however, in the previously mentioned study involving subelite rugby league players by johnston and colleagues[7] almost certain substantial reductions in pp peak power were observed immediately post-match, while likely substantial reductions were reported 24 and 48 h post-match. unfortunately a direct comparison with the present study cannot be made, as this metric was not included in the analysis due to unacceptable reliability in this population.[9] perception of well-being demonstrated almost certain substantial reductions at 24 h post-game and remained very likely and likely substantially reduced at 48 h and 72 h post-match. in senior collisionsport athletes, reductions in perception of well-being have been reported to peak at 24 h post-match and gradually return to baseline thereafter.[11] a similar trend occurred in the present study with only small (-3.6±3.7%) decreases being observed by 72 h post-match. in the present study, ck peaked in the first 24 h post-match, which is in accordance with findings from other studies in both junior[7] and senior[5,11] collision sport athletes. elevations in ck have been associated with damage to skeletal muscle tissue, either from direct trauma during collisions[4] or repetitive eccentric damage during high-speed running[5,11] throughout match-play. the resulting disruption of skeletal muscle integrity leads to leakage of ck into the bloodstream.[15] the results demonstrate that biochemical homeostasis had not been restored by 72 h, with ck levels still very likely substantially elevated (56.7±34.5%) at this time. however, the consequence of this is unclear. given that lower-body neuromuscular recovery was evident by 72 h, the large elevation in ck at this time may reflect the rate of ck clearance from the blood,[15] and not the extent of muscle damage. the results of the present study also demonstrate the individual nature of recovery following match-play in academy rugby union players. figure 1 shows that even when the group mean demonstrated near full recovery, certain individuals still exhibited negative changes that were greater than the swc. these findings emphasise that although understanding a group response provides valuable information on the recovery in the days post-match, it is important for practitioners to monitor the recovery of each individual player following competition. a limitation of the present study is the analysis of only one competitive match. however, the total distance covered in the current study (4691±878 m) was similar to the average distances reported from five games (4470±292 m) by venter et al.[16] in under-19 provincial players, suggesting this may represent academy rugby match demands. however, future research involving a greater number of observations is needed to further investigate the specific demands of match-play that result in post-match fatigue in academy rugby union players. furthermore, such research may also provide insight into positional differences, both in terms of the specific match demands that cause fatigue, and the magnitude of fatigue following match play. sajsm vol. 28 no. 1 2016 5 original research conclusion the findings of the present study demonstrate the transient and multidimensional nature of post-match fatigue in academy rugby union players. a decrease in upper-body nmf was very likely for up to 24 h but was unlikely beyond this point, while lower-body nmf was still likely decreased at 48 h before returning to baseline. in contrast, perception of well-being and ck were negatively altered from immediately to 72 h post-match, although returning towards baseline at this time. furthermore, the results demonstrate the individual nature of recovery, with many players demonstrating different recovery profiles from the group average. references 1. cahill n, lamb k, worsfold p, et al. the movement characteristics of english premiership rugby union players. j sports sci 2013;31(3):229-237. [http://dx.doi.org /10.1080/02640414.2012.727456] 2. cunniffe b, hore aj, whitcombe dm, et al. time course of changes in immuneoendocrine markers following an international rugby game. eur j appl physiol 2010;108(1):113-122. [http://dx.doi.org/10.1007/s00421-009-1200-9] 3. west dj, finn cv, cunningham dj, et al. neuromuscular function, hormonal, and mood responses to a professional rugby union match. j strength cond res 2014;28(1):194-200. [http://dx.doi.org/10.1519/jsc.0b013e318291b726] 4. takarada y. evaluation of muscle damage after a rugby match with special reference to tackle plays. br j sports med 2003;37(5):416-419. [http://dx.doi.org/10.1136/ bjsm.37.5.416] 5. jones m, west d, harrington b, et al. match play performance characteristics that predict post-match creatine kinase responses in professional rugby union players. bmc sports sci med rehabil 2014;6(1):38. [http://dx.doi.org/10.1186/2052-1847-6-38] 6. wehbe g, gabett tj, dwyer d, et al. monitoring neuromuscular fatigue in team-sport athletes using a cycle-ergometer test. int j sports physiol perform 2015;10(3):292-297. [http://dx.doi.org/10.1123/ijspp.2014-0217] 7. johnston rd, gabbett tj, jenkins dg, et al. influence of physical qualities on postmatch fatigue in rugby league players. j sci med sport 2015;18(2):209-213. [http:// dx.doi.org/10.1016/j.jsams.2014.01.009] 8. johnston rd, gabbett tj, jenkins dg. influence of an intensified competition on fatigue and match performance in junior rugby league players. j sci med sport 2013;16(5):460-465. [http://dx.doi.org/10.1016/j.jsams.2012.10.009] 9. roe g, darrall-jones j, till k, et al. between-day reliability and sensitivity of common fatigue measures in rugby players. int j sports physiol perform 2015, sep 21. [epub ahead of print] [http://dx.doi.org/10.1123/ijspp.2015-0413] 10. mclean bd, coutts aj, kelly v, et al. neuromuscular, endocrine, and perceptual fatigue responses during different length between-match microcycles in professional rugby league players. int j sports physiol perform 2010;5(3):367-383. [http://dx.doi. org/10.1123/ijspp.5.3.367] 11. twist c, waldron m, highton j, et al. neuromuscular, biochemical and perceptual post-match fatigue in professional rugby league forwards and backs. j sports sci 2012;30(4):359-367. [http://dx.doi.org/10.1080/02640414.2011.640707] 12. foster c, florhaug ja, franklin j, et al. a new approach to monitoring exercise training. j strength cond res. 2001;15(1):109-115. [http://dx.doi.org/ 10.1519/00124278-200102000-00019] 13. hopkins wg, marshall sw, batterham am, et al. progressive statistics for studies in sports medicine and exercise science. med sci sports exerc. 2009;41(1):3-13 [http:// dx.doi.org/10.1249/mss.0b013e31818cb278] 14. boyas s, guével a. neuromuscular fatigue in healthy muscle: underlying factors and adaptation mechanisms. annals phys rehabil med 2011;54(2):88-108. [http:// dx.doi.org/10.1016/j.rehab.2011.01.001] 15. baird mf, graham sm, baker js, et al. creatine-kinaseand exercise-related muscle damage implications for muscle performance and recovery. j nutr metabolism 2012; 2012:960363. [http://dx.doi.org/10.1155/2012/960363] 16. venter re, opperman e, opperman s. the use of global positioning system (gps) tracking devices to assess movement demands and impacts in under-19 rugby union match play. afr j phys health ed rec dance 2011;17(1):1-8. [http://dx.doi. org/10.4314/ajpherd.v17i1.65242] http://dx.doi.org/10.1080/02640414.2012.727456 http://dx.doi.org/10.1080/02640414.2012.727456 http://dx.doi.org/10.1007/s00421-009-1200-9 http://dx.doi.org/10.1519/jsc.0b013e318291b726 http://dx.doi.org/10.1136/bjsm.37.5.416 http://dx.doi.org/10.1136/bjsm.37.5.416 http://dx.doi.org/10.1186/2052-1847-6-38 http://dx.doi.org/10.1123/ijspp.2014-0217 http://dx.doi.org/10.1016/j.jsams.2014.01.009 http://dx.doi.org/10.1016/j.jsams.2014.01.009 http://dx.doi.org/10.1016/j.jsams.2012.10.009 http://dx.doi.org/10.1123/ijspp.2015-0413 http://dx.doi.org/10.1123/ijspp.5.3.367 http://dx.doi.org/10.1123/ijspp.5.3.367 http://dx.doi.org/10.1080/02640414.2011.640707 http://dx.doi.org/ 10.1519/00124278-200102000-00019 http://dx.doi.org/ 10.1519/00124278-200102000-00019 http://dx.doi.org/10.1249/mss.0b013e31818cb278 http://dx.doi.org/10.1249/mss.0b013e31818cb278 http://dx.doi.org/10.1016/j.rehab.2011.01.001 http://dx.doi.org/10.1016/j.rehab.2011.01.001 http://dx.doi.org/10.1155/2012/960363 http://dx.doi.org/10.4314/ajpherd.v17i1.65242 http://dx.doi.org/10.4314/ajpherd.v17i1.65242 sajsm 563.indd sajsm vol. 26 no. 3 2014 91 commentary abrasion injuries result in damage only to the surface layer of skin and can result in player discomfort and changes in performance. the perceived fear of abrasion injuries on artificial turf playing surfaces has significantly affected the adoption of these surfaces, particularly in sports that involve frequent player-surface interactions. the underreporting of abrasion injuries due to how time-loss injuries are defined and the lack of validity of the current abrasion measurement device highlight the need for more research to understand fully the incidence and nature of abrasions on artificial turf playing surfaces and the effect of these injuries on playing behaviour. improved reporting of abrasion injuries and a more biofidelic test device could assist in both the development of abrasion-related injury prevention strategies and in dispelling players’ negative perceptions of abrasions on artificial turf. s afr j sm 2014;26(3):91-92. doi:10.7196/sajsm.563 abrasion injuries on artificial turf: a real risk or not? d m twomey,1 phd; l a petrass,1 phd; p r fleming,2 phd 1 faculty of health, federation university australia, mt helen campus, victoria, australia 2 school of civil and building engineering, loughborough university, united kingdom corresponding author: d m twomey (d.twomey@federation.edu.au) abrasion injuries result in damage only to the surface layer of skin (epidermis), and while typically classified as minor in nature, can engender player discomfort and consequently result in a change in playing behaviour.[1] strategies to reduce the incidence of abrasion injuries in sport are therefore desirable. while it is difficult to replicate natural turf fully, the perceived fear of abrasion-type injuries on artificial turf is surprising given the fact that, unlike natural turf, artificial turf fields are required to satisfy a set of safety and performance standards that include an abrasion measure. injury studies on the earlier generations of artificial turf products (i.e. prior to the late 1990s) consistently reported an increase in the number of abrasion injuries on artificial turf compared with natural grass.[2] since then, studies have been undertaken on third-generation (3g) surfaces with longer fibres and infilled with rubber and sand, but abrasion injuries are still consistently higher than on natural turf. in terms of total injuries recorded in published injury studies, however, overall abrasion injury rates are relatively low, ranging from ~2.5% to 6%.[3,4] these low rates may be largely owing to the injury definitions used, which are generally based on time loss and may be a rare occurrence with abrasion-type injuries unless they are recurrent or become inflamed/infected. more detailed and accurate reporting of abrasion injuries in future injury studies is needed to appreciate the extent of the problem fully. another issue that arises when interpreting abrasion injury incidence to date is that this type of injury is regularly reported with lacerations (injuries to multiple layers of skin) or as part of skinrelated injuries; therefore, it is difficult to have confidence in the relative risk of abrasion injuries alone. given that the mechanism of laceration injuries is very different to abrasion injuries, strategies to prevent these injuries need different considerations. consequently, it is plausible that the total incidence of abrasion injuries may be significantly underestimated in many injury epidemiological studies, and the effect of these injuries could be much greater than anticipated. recently, peppelman et al.[5] were the first to attempt to increase understanding of the effect of sliding on natural and 3g artificial turf surfaces on in vivo human skin. they concluded that sliding on natural grass resulted in more erythema (redness), but fewer abrasions compared with sliding on artificial turf. they contended that these observed differences may be important in studying the skin comfort of players using artificial turf surfaces, and suggested that the discomfort associated with abrasion injuries can negatively influence players’ performance and change their playing behaviour.[5] if players are changing their playing behaviour to protect skin abrasions from further injury during the regeneration and remodelling phases of healing, they may in fact increase their risk of other injuries. more detailed and accurate reporting in this area would provide valuable insights into the real effect of abrasion injuries. regardless of the lack of epidemiological data on abrasion injuries on 3g artificial turf, it appears that players perceive abrasion injuries as a real risk and a potential barrier to their acceptance of such surfaces. due to the early adoption of 3g artificial turf in soccer, player perceptions of 3g artificial turf are limited predominantly to this sport. consistently, players have concerns about the effect of the surface on both technical and physical performance, particularly the risk and severity of abrasions as a result of sliding tackles and falls on artificial turf.[6-8] in the italian amateurs league, over 1 600 male players aged between 15 and 35 years reported concerns about the risk of abrasion in sliding tackles.[8] in terms of abrasions, players’ role in the team (goalkeeper, defender, midfielder and forward) influenced their perception, with defenders and midfielders scoring the surface worse for abrasions than goalkeepers and forwards. this finding is 92 sajsm vol. 26 no. 3 2014 likely to be explained by the playing characteristics associated with these different roles, with defenders and midfielders more likely to have recurrent player-ground interaction due to sliding tackles and attempting intercepts. in a more recent study, spanish male amateur football players (aged 16 36 years) provided very poor ratings for the safety aspects associated with artificial turf, including skin abrasions, muscle strains and the general possibility of sustaining an injury. [6] for most players, the biggest disadvantage associated with artificial turf was skin abrasion, specifically in sliding tackles. perceptions of amateur-level players are consistent with studies conducted with elitelevel players. a large study conducted with male (n=1 018) and female (n=111) elite players of similar age to participants in the previous studies indicated that >60% felt that artificial turf was too abrasive. [7] while artificial turf provides a valuable alternative to natural grass in areas experiencing extreme climatic conditions, negative player perceptions need to be addressed to ensure that these surfaces are successfully adopted. artificial surfaces are becoming increasingly popular for a wide range of other football codes, especially with surfaces designed for multisport usage. as abrasion has been identified as an issue for soccer, this is likely to emerge as a more prominent issue for players of other football codes that have greater player-surface contact through various forms of sliding tackles. in fact, the perceived risk of abrasion and discomfort may start to affect players’ uptake of these surfaces for both training and competition, which could negatively affect participation rates and the associated health benefits. while there is huge variability and substantial product development and improvement in artificial turf, which could change the properties of these surfaces, it is still possible that users’ perceptions are likely to be largely influenced by available information and the appearance of the facility. it is important that the abrasion measures performed on all emerging artificial turf products are ecologically valid to accurately reflect the level of abrasion likely to be encountered when players interact with the surface during tackling manoeuvres. currently, 3g artificial turf products need to satisfy an abrasion standard in order to be certified for use by governing bodies of specific sports. in the football codes of soccer, rugby union, rugby league, australian football and gaelic football, a mechanical device called the securisport is approved to measure a value for skin abrasion and skin friction of the surface. this device firstly measures the coefficient of friction between a test foot (covered in a silicone skin) and a polished steel plate, and then between the test foot and the artificial turf product. the level of abrasiveness of the surface is quantified as the percentage difference between the force measures on the steel plate with the new skin compared with the abraded skin after it has been tested on the artificial turf product. a major limitation of this device is the way in which it moves over the artificial surface during testing. the test foot performs five complete revolutions at a speed of 40 (standard deviation 1) revolutions/minute under a very low normal force of 100 n. interestingly, there is no supporting research evidence for five revolutions representing an appropriate simulation of the level of damage or the level of normal load, and this rotational movement does not replicate the player surface interaction of many sports played on 3g artificial turf surfaces. this lack of biofidelity highlights the fact that although artificial turf may satisfy abrasion standards, some artificial turf products may indeed be too abrasive to withstand the player-surface interaction of the sport without resulting in injury to the skin. in conclusion, players perceive an increased risk of abrasion injuries on artificial turf, which leads to a negative attitude in the adoption of these surfaces. owing to the time-loss injury definitions used in many injury epidemiological studies, it is likely that abrasion injuries are underreported and hence their effect on players is underestimated. more work is needed to improve the reporting of abrasion injuries and validity of testing devices to understand fully the incidence and nature of abrasions on artificial turf surfaces, and the effect of these injuries on playing behaviour. references 1. van den eijnde waj, peppelman m, lamers ea, et al. understanding the acute skin injury mechanism caused by player-surface contact during soccer: a sur vey and systematic review. orthopaedic journal of sports medicine 2014;2(5):2325967114533482. [http://dx.doi.org/10.1177/2325967114533482] 2. ekstrand j, nigg b. surface-related injuries in soccer. sports med 1989;8(1):56-62. 3. soligard t, bahr r, andersen te. injury risk on artificial turf and grass in youth tournament football. scand j med sci sports 2012;22(3):356-361. [http://dx.doi. org/10.1111/j.1600-0838.2010.01174.x] 4. fuller cw, dick rw, corlette j, et al. comparison of the incidence, nature and cause of injuries sustained on grass and new generation artificial turf by male and female football players. part 2: training injuries. br j sports med 2007;47(suppl 1):i27-i32. [http://dx.doi.org/10.1136/bjsm.2007.037275] 5. peppelman m, van den eijnde waj, langewouters amg, et al. the potential of the skin as a readout system to test artificial turf systems: clinical and immunohistological effects of a sliding on natural grass and artificial turf. int j sports med 2013;34(9):783788. [http://dx.doi.org/10.1055/s-0032-1331173] 6. burillo p, gallardo l, felipe jl, et al. artificial turf surfaces: perception of safety, sporting feature, satisfaction and preference of football users. eur j sport sci 2014;14(suppl 1):s437-s447. [http://dx.doi.org/10.1080/17461391.2012.713005] 7. roberts j, osei-owusu p, harland a, et al. elite football players’ perceptions of football turf and natural grass surface properties. procedia eng 2014;72:907-912. [http://dx.doi.org/0.1016/j.proeng.2014.06.150] 8. zanetti, em. amateur football game on artificial turf: players’ perceptions. appl ergon 2009;40(3):485-490. [http://dx.doi.org/10.1016/j.apergo.2008.09.007] sajsm 595 (commentarty).indd position statement 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license recommendations for the return of spectators to sport stadiums: a south african sports medicine association (sasma) position statement – part 4 l pillay,1,2,3,4 mbchb, msc; j patricios,2 mbbch, mmedsci; dc janse van rensburg,1,5 md, mmed, msc, mbchb; r saggers,2,9 mbbch, fcpaed, mmed; d ramagole,1 mbchb, msc; p viviers,6,7,8 mbbch, mmedsc; c thompson,6,7,8 mbchb, mphil; s hendricks,10,11,12 phd 1 section sports medicine & sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa 2 wits sport and health (wish), faculty of health sciences, university of the witwatersrand, johannesburg, south africa 3 premier soccer league covid-19 chief medical officer, psl, south africa 4 chief medical officer, gauteng lions cricket, south africa 5 medical board member, world netball, manchester, uk 6 campus health service, stellenbosch university, south africa 7 institute of sport and exercise medicine, division of orthopaedic surgery, department of surgical sciences, faculty of medicine and health sciences, stellenbosch university, south africa 8 fifa medical centre of excellence, south africa 9 department of paediatrics and child health, charlotte maxeke johannesburg academic hospital, johannesburg, south africa 10 division of physiological sciences, department of human biology, faculty of health sciences, university of cape town, south africa 11 health through physical activity, lifestyle and sport (hpals) research centre, department of human biology, faculty of health sciences, university of cape town. south africa 12 carnegie applied rugby research (carr) centre, institute for sport physical activity and leisure, leeds beckett university, leeds, england corresponding author: l pillay (drpillay@absamail.co.za) several sporting codes have returned to competition around the world. recently, the tokyo olympics and paralympics, postponed from 2020, concluded safely, albeit with no spectators and the rigorous daily testing of participants.[1] in south africa, all sporting federations were given the green light to resume professional sport on 20 august 2020 by the ministry of sports, art and culture.[2] this resumption was based on specific conditions, such as covid-19 pcr tests, continuous education, daily screening, and no spectators allowed. early this year, the south african sports confederation and olympic committee (sascoc), together with the event and safety council (esc), was mandated by the department of sports, culture and recreation (dsacr) to develop a document to explain what processes should be put in place for the safe return of spectators.[3] the first country to host spectators after covid-19 was declared a pandemic was qatar. this was in december 2020 at the amir cup final.[4] a total of twenty thousand spectators were allowed to enter (50% of the stadium capacity) subject to a negative antigen test not older than 72 hours. social distancing, temperature screening and mask-wearing (non-pharmaceutical interventions or npis) were mandatory before entry. the results of the antigen test and monitoring were captured using a geolocating cell phone app and online booking system. while this was a costly exercise for both the organisers and spectators (the spectator had to pay for any testing that was required), as far as the researchers were aware, the final was a success in terms of managing the risk of covid-19. the researchers did not have access to the post-match track and trace app statistics for spectators. the euro 2020 uefa competition (held in 11 different european countries from 11 june 2021 to 11 july 2021) also allowed spectators.[5] similar to the amir cup final, the spectators of the euro 2020 uefa competition had to manage the covid-19 risk using npis and a negative covid-19 test. international experience shows that in the time leading to the euro 2020 uefa competition, covid-19 vaccines were also available, which added another risk mitigating layer to reduce the spread of the covid-19 virus. recommendations for spectators at stadiums for professional sport considering the above, the following is recommended to allow spectators to return safely to stadiums in south africa. any competition wanting to return spectators should consult the relevant stakeholders and would be required to comply with the dsacr and department of health regulated requirements. this would include the national federations together with the esc: stadium protocols 1. there should be a stepwise approach for allowing fans into stadiums; for example, initially at 10% of venue capacity, then 25%, then 50% (within keeping to the disaster management act regulation regarding indoor and outdoor maximum capacities). it will als o allow for appropriate social distancing to occur (at least one empty seat between spectators). seats must be allocated, and spectators must utilise these allocated seats as this is vital for contact tracing. stadiums and spectators will be able to familiarise themselves with the logistics and processes required. after every event, there should be a post -event all sports were discontinued in 2020 with the arrival of covid-19. since then most have been reinstated, albeit without spectators. however, several countries have put together a number of different risk-mitigating strategies to allow spectators back into stadiums. this position statement gives an outline of the minimum requirements that should be considered upon the return of spectators at live sporting events. keywords: covid-19, risk-mitigating, events, spectators, sports s afr j sports med 2021; 33:1-3. doi: 10.17159/2078-516x/2021/v33i1a12558 mailto:drpillay@absamail.co.za http://dx.doi.org/10.17159/2078-516x/2021/v33i1a12558 https://orcid.org/0000-0002-5341-6080 https://orcid.org/0000-0002-8353-3376 https://orcid.org/0000-0001-6593-8049 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0002-3416-6266 https://orcid.org/0000-0003-1058-6992 https://orcid.org/0000-0001-6682-3438 position statement sajsm vol. 33 no. 1 2021 2 dissection of the pearls and pitfalls and improvements accordingly prior to moving to the next level of spectator allowance. 2. stadium protocols are already in place regarding the sanitisation of the stadium, ablution facilities, and easily available hand sanitisers/handwashing stations. however, these may need to be increased. staggered ingress and egress of stadiums are required, ensuring there are no mass crowd gatherings, and social and physical distancing (at least 1.5 metres apart). 3. covid-19-related educational posters around the stadium must remind spectators to keep a social distance of at least 1.5 m, wearing masks properly and sanitising of their hands. 4. staff working at the event must be fully vaccinated. 5. should there be an indoor event, cross ventilation [6] is vital and high efficiency particle air (hepa) purifiers should be considered.[7] mandatory spectator conditions 6. mandatory mask-wearing covering the nose and mouth at all times. 7. proof of full vaccination (this means 14 days after a johnson and johnson vaccination or 2 weeks after the second pfizer vaccination) [8] needs to be provided – this should be confirmed when purchasing the ticket and at entry into the stadium; proof of vaccination must be crosschecked against the national electronic vaccination data system (evds). 8. tickets cannot be transferred. 9. spectators must also realise that even though all protocols are observed, the risk of contracting covid-19 cannot be mitigated 100%. this should be covered in a disclaimer when purchasing the ticket. screening and surveillance 10. a mobile covid-19 screening app with questions to screen symptoms and exposure in the last 14 days. 11. the world health organization (who) mass gathering covid-19 risk assessment tool sports events should be utilised by the event planning team. [9] 12. there must be a system in place for spectators (who, within five days of the event, find out they have teste d positive for covid-19) to contact and advise planners so that contact tracing can be undertaken. 13. stadiums must also have the ability to do rapid antigen tests onsite, or be able to transport an attendee (spectator or staff) to the nearest antigen test site, should an attendee screen positive for any covid-19 symptoms. 14. constant countrywide surveillance of covid-19 transmission patterns must be a major dictator of whether or not spectators may attend events. recommendations for spectators in amateur sport – club and school 1. the usual npi protocols must continue. 2. all spectators must be screened (via symptom questionnaire and temperature) prior to entry into the stadium. 3. there should be a maximum capacity of 50% of spectators or as dictated by the gazetted regulations by the minister of sports, art and culture. 4. where an event is indoors, cross ventilation is vital and high efficiency particulate air (hepa) purifiers should be considered. 5. anyone screened at the event who poses a risk of recent exposure to covid-19 or presents with symptoms must not be allowed entry. 6. constant countrywide surveillance of covid-19 transmission patterns must be a major dictator of whether or not spectators may attend events. conclusion this pandemic will likely last for many more months or even years. vaccination is most important and should be encouraged as this will assist in returning to the pre-pandemic status quo as per the government’s new vaccination campaign on ’return to play ‘[10]. with evolving evidence, changes should be implemented regularly. new virus mutations will occur. however, we should have a malleable plan to allow spectators to socialise safely with all risk mitigating approaches and protocols in place. conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: lp conceptualised, drafted and finalised the manuscript. djvr, dr, jp, ct, pv, rs and sh critically reviewed the drafts. all involved approved the final version prior to submission. references 1. international olympic committee (ioc). ’the olympic games of hope, solidarity and peace’: how tokyo 2020 helped bring the world together. 2021. https://olympics.com/ioc/news/-theolympic-games-of-hope-solidarity-and-peace-how-tokyo-2020helped-bring-the-world-together (accessed 12 september 2021) 2. republic of south africa. government gazette.2020;. 662, 43667. disaster management act (57/2002) amendment of directions issued in terms of regulation 4(10) of the regulations. measures to prevent and combat the spread of covid-19. https://www.srsa.gov.za/sites/default/files/43667gon943.pdf (accessed 12 september 2021). 3. aaxo. the association of african exhibition organisers. the event safety council remains committed to creating a safe environment for events across the business, sport and entertainment sectors. https://www.aaxo.co.za/the-event-safetycouncil-remains-committed-to-creating-a-safe-environment-forevents-across-the-business-sport-and-entertainment-sectors/ (accessed 12 september 2021) 4. dergaa i, varma a, tabben m, et al. organising football matches with spectators during the covid-19 pandemic: what can we learn from the amir cup football final of qatar 2020? a call for action. biol sport 2021;38(4):677–681. [doi: 10.5114/biolsport.2021.103568] 5. uefa euro 2020 code of conduct for spectators, march 2021. https://editorial.uefa.com/resources/0268-11fe383565368f3c3625933e-1000/20210408_uefa_euro_2020_code_of_ conduct__spectators_final.pdf (accessed 12 september 2021) 6. world health organization. roadmap to improve and ensure good indoor ventilation in the context of covid-19. 2021. https://apps.who.int/iris/bitstream/handle/10665/339857/ 9789240021280-eng.pdf?sequence=1&isallowed=y (accessed 12 september 2021) 7. liu dt, philips km, speth mm, et al.. portable hepa purifiers to eliminate airborne sars-cov-2: a systematic review. otolaryngol – head neck surg 2021; 1945998211022636. https://olympics.com/ioc/news/-the-olympic-games-of-hope-solidarity-and-peace-how-tokyo-2020-helped-bring-the-world-together https://olympics.com/ioc/news/-the-olympic-games-of-hope-solidarity-and-peace-how-tokyo-2020-helped-bring-the-world-together https://olympics.com/ioc/news/-the-olympic-games-of-hope-solidarity-and-peace-how-tokyo-2020-helped-bring-the-world-together https://www.srsa.gov.za/sites/default/files/43667gon943.pdf https://www.aaxo.co.za/the-event-safety-council-remains-committed-to-creating-a-safe-environment-for-events-across-the-business-sport-and-entertainment-sectors/ https://www.aaxo.co.za/the-event-safety-council-remains-committed-to-creating-a-safe-environment-for-events-across-the-business-sport-and-entertainment-sectors/ https://www.aaxo.co.za/the-event-safety-council-remains-committed-to-creating-a-safe-environment-for-events-across-the-business-sport-and-entertainment-sectors/ doi:%2010.5114/biolsport.2021.103568 https://editorial.uefa.com/resources/0268-11fe38356536-8f3c3625933e-1000/20210408_uefa_euro_2020_code_of_%20conduct_-_spectators_final.pdf https://editorial.uefa.com/resources/0268-11fe38356536-8f3c3625933e-1000/20210408_uefa_euro_2020_code_of_%20conduct_-_spectators_final.pdf https://editorial.uefa.com/resources/0268-11fe38356536-8f3c3625933e-1000/20210408_uefa_euro_2020_code_of_%20conduct_-_spectators_final.pdf https://apps.who.int/iris/bitstream/handle/10665/339857/%209789240021280-eng.pdf?sequence=1&isallowed=y https://apps.who.int/iris/bitstream/handle/10665/339857/%209789240021280-eng.pdf?sequence=1&isallowed=y position statement 3 sajsm vol. 33 no. 1 2021 [doi: 10.1177/01945998211022636] [pmid: 34098798] 8. south africa. national institute for communicable diseases (nicd). what you need to know once you’ve been vaccinated. 2021. https://www.nicd.ac.za/what-you-need-to-know-onceyouve -been-vaccinated/ (accessed 12 september 2021) 9. world health organization. who mass gathering covid-19 risk assessment tool – sports events. 2020. https://apps.who.int/ iris/handle/10665/333187 (accessed 12 september 2021) 10. south african government. sports, arts and culture launches “return to play – it’s in your hands” national campaign, 8 sept. 2021. https://www.gov.za/speeches/sport-arts-and-culturelaunches-%e2%80%9creturn-play-%e2%80%93-it%e2%80%99syour-hands%e2%80%9d-national-campaign-8-sept-7 (accessed 12 september 2021) doi:%2010.1177/01945998211022636 https://www.nicd.ac.za/what-you-need-to-know-once-youve%20-been-vaccinated/ https://www.nicd.ac.za/what-you-need-to-know-once-youve%20-been-vaccinated/ https://apps.who.int/%20iris/handle/10665/333187 https://apps.who.int/%20iris/handle/10665/333187 https://www.gov.za/speeches/sport-arts-and-culture-launches-%e2%80%9creturn-play-%e2%80%93-it%e2%80%99s-your-hands%e2%80%9d-national-campaign-8-sept-7 https://www.gov.za/speeches/sport-arts-and-culture-launches-%e2%80%9creturn-play-%e2%80%93-it%e2%80%99s-your-hands%e2%80%9d-national-campaign-8-sept-7 https://www.gov.za/speeches/sport-arts-and-culture-launches-%e2%80%9creturn-play-%e2%80%93-it%e2%80%99s-your-hands%e2%80%9d-national-campaign-8-sept-7 sajsm vol 18 no. 3 2006 93 introduction at present the south african fitness industry has not been well researched, and no comprehensive inventory exists that lists all facilities comprising this industry. among many of the key players within the south african fitness industry, there seems to be a general awareness of the facilities and service providers in the larger multipurpose gyms and health clubs, but there is limited information available concerning smaller, single-purpose clubs, community-based organisations and self-employed fitness instructors. the international health, racquet and sportsclub association (ihrsa) works to produce data on the fitness industry worldwide, mainly through their annual global report – state of the health club industry 3 and their european market report. 5 based in the usa, ihrsa also conducts an industry data survey of the health and fitness club industry 4 within the usa. data in this survey include, among other measures, club member demographics, club membership growth, club facilities, club growth, benchmarks by club type and size, and club prices. ihrsa has links with fitness associations in other countries and helps those organisations to produce similar reports. currently south africa does not have a single entity representing the fitness industry, and to date, no equivalent of the ihrsa industry surveys and report. this should be seen original research article an inventory of the south african fitness industry catherine e draper1 (ma, phd) liesl grobler1 (phd) georgina a kilian2 (mba) lisa k micklesfield1 (phd) estelle v lambert1 (ms, phd) timothy d noakes1 (mb chb, md, dsc, facsm) 1 uct/mrc research unit for exercise science and sports medicine, university of cape town 2 sports science institute of south africa, cape town abstract objective. the aim of this study was to create an inventory of fitness facilities in south africa, their location, equipment and services offered, and the demographics, education and training of the staff working in these facilities. design. a total of 750 facilities were identified, and descriptive data were gathered from 442 facilities (59%) with the use of a questionnaire administered telephonically and via the website of the sports science institute of south africa. setting. the study was initiated by the sports science institute, and the results were presented at the 4th annual discovery vitality fitness convention on 4 may 2006. results. results show that the industry comprises mainly independent facilities (68%). all types of facilities were found to be located mostly within urban areas, and reported providing services to just less than 2% of the south african population. facilities offer a wide range of equipment and services to their members. of the fitness-related staff at facilities, the majority were reported to be young (18 25 years, 55% of male, and 49% of female staff), and in terms of racial proportions most staff were white (males 40% of total staff and females 33% of total staff). correspondence: cathi draper uct/mrc research unit for exercise science and sports medicine sports science institute of south africa boundary road newlands 7700 tel: (021) 650 4567 e-mail: cdraper@sports.uct.ac.za less than a quarter of fitness-related staff hold university qualifications, and just over 80% of instructors hold qualifications aligned with the national qualifications framework. the importance of education and training of staff was emphasised by respondents. conclusions. this report highlights the widespread value of assessing the fitness industry, particularly within the context of the rise of chronic diseases in south africa and government initiatives to promote healthy lifestyles. pg93-104.indd 93 9/21/06 12:29:38 pm 94 sajsm vol 18 no. 3 2006 as important as the fitness industry represents a significant vehicle for social and economic development in south africa, as employer, through the provision of jobs, and as consumer, through improving health and thereby potentially reducing the burden of disease. 13-15 ideally, as a country and economy undergoing transition, south africa requires its own industry standards and benchmarks, to meet specific needs and underserved communities. in addition, those in the south african fitness industry should have an accurate picture of the industry as a whole in order to respond appropriately to the health and fitness needs of the people they are aiming to serve. shortfalls in the industry must also be identified against these needs. within the south african context, there are a number of governmental drives promoting physical activity, such as the ‘vuka sa – move for your health’ initiative, sport and recreation’s mass participation programme, the youth fitness and wellness charter, and the health-promoting schools initiative. these initiatives are a response to the rise in chronic diseases, both nationally and internationally, and the identification of the lack of physical activity as a risk factor for many of these diseases. 6-8,11-15 this makes it essential for south africans to engage in physical activity and take responsibility for their health, and the fitness industry undoubtedly has a major role to play in promoting this. it is not only important to assess what role this industry is playing in getting and keeping south africans active, but it is also important to evaluate the extent to which the needs of all south africans are being, or can be, met by the industry. therefore, this study aimed to answer the following research questions: • what fitness facilities exist in south africa? • where are these facilities located within south africa? • what equipment, facilities and services are offered at those facilities? • what are the demographics of the staff employed in those facilities? • what is the level of education and training of fitness-related staff currently employed in those facilities? methodology sample selection for the purposes of this research, the fitness industry is defined to include all multipurpose fitness centres, single-purpose fitness centres, exercise programmes within community halls or centres, hospital fitness centres, corporate fitness centres, hotel or resort fitness centres, college and university fitness centres, military fitness centres, aerobics, dance, katabox, pilates, yoga and cycling studios. personal trainers and instructors without a fixed place of practice or employment were included, but all sporting clubs, facilities and organisations, whether recreational or competitive, were not included. participants and facilities were sourced via the telephone directory (white and yellow pages), the internet and through personal networking and informers. ethical approval for this study was obtained from the research ethics committee at the university of cape town. data-gathering methods a questionnaire was developed and pilot tested among key informants in the fitness industry who were known to the research team, and appropriate changes were made. individuals who own or manage the specific facilities were contacted, and the questionnaire was then emailed to contacts for whom email addresses could be sourced. a number of questionnaires were administered telephonically by the research team, and respondents were also able to fill in the questionnaire via the sports science institute of south africa (ssisa) website. other contacts were referred to a call centre which administered the questionnaire on behalf of the research team. a total of 750 facilities were sourced and ‘geocoded’ at suburb level. for this process of ‘geocoding’, the geographical co-ordinates of the suburb in which each facility is located are plotted geographically, and results of this process are represented in fig. 1. fifty-nine per cent of the 750 facilities (n = 442) responded to the questionnaire. the remaining 308 facilities either did not complete the questionnaire or they could not be contacted because of incorrect contact details. results nature of facilities respondents were asked to choose from a list of options that best described the fitness facility in which they work, and from these descriptions, facilities were then divided into four categories: (i) independent facilities (68%), which included independent multipurpose fitness centres, single-purpose fitfig. 1. geocoding of 750 fitness facilities currently operating in south africa. pg93-104.indd 94 9/21/06 12:29:39 pm sajsm vol 18 no. 3 2006 95 ness centres, and group exercise studios for disciplines such as pilates, yoga and cycling; (ii) informal facilities (14%), which included facilities that do not have dedicated exercise space or equipment, such as running and walking groups, exercise programmes in a community centre/hall/church hall; (iii) specialist facilities (7%), which included facilities that exist because of the environment in which they are placed, such as facilities at tertiary academic institutions, hotels and resorts, hospitals and in corporate settings; and (iv) gym chains (11%), which included multipurpose fitness facilities with more than one club under the same name. size of facilities the average square meterage per facility with dedicated exercise space was calculated to be 1154 m 2 (n = 226), ranging from 20 m 2 to 50 000 m 2 . the average number of members per square meter for this type of facility was 1.8. the accuracy of this figure is, however, dependent on the information provided by facilities, as many respondents were only able to estimate the number of members and only 226 facilities were able to give the square meterage of their facility. the total number of members in the 442 facilities that reported their membership came to 813 012, only 1.73% of the total south african population estimated for 2005. 9 location and distribution of facilities of the 442 facilities that responded to the questionnaire, 270 were placed in a large city, with 149 in a small city or town, and only 23 in a rural area. definitions of these types of areas were not stipulated in the questionnaire, so the accuracy of these figures relies completely on the respondents’ perceptions of the area in which they are placed. fig. 1 shows the provincial distribution of the facilities in south africa, and fig. 2 presents this provincial distribution alongside the population density of each province in south africa. 2 it is clear from these figures that the distribution of facilities within south african provinces does seem generally to match the population density of these provinces, except for the western cape, which has the second highest number of fitness facilities (234) but a relatively low population density (36 persons per km 2 ). equipment, facilities and services offered respondents were also asked to comment on the equipment, facilities, classes and programmes made available to the members of their facilities (figs 3 and 4). most facilities were able to provide exercise mats and free weights, and to a lesser degree cardiovascular equipment and mechanical resistance equipment (fig. 3). the average number of group fitness sessions offered per week by facilities was 18. eightyone per cent of facilities reported offering classes or programmes to the inactive or new exerciser, and fig. 5 presents the various classes and programmes available to members. fig. 2. provincial distribution of south african fitness facilities and provincial population density in south africa (persons per km2). 1 fig. 1. geocoding of 750 fitness facilities currently operating in south africa 0 100 200 300 400 500 600 g a u te n g k w a z u lu n a ta l l im p o p o m p u m a la n g a e a st e rn c a p e w e st e rn c a p e n o rt h w e st f re e s ta te n o rt h e rn c a p e population density fitness facilities fig. 2. provincial distribution of south african fitness facilities and provincial population density in south africa (persons per km 2 ). fig. 3. equipment available to members of fitness facilities. 2 0% 20% 40% 60% 80% 100% exercise mats free weights cardiovascular equipment mechanical resistance equipment group exercise studios steps and platforms stability balls balance equipment boxing equipment fig. 3. equipment available to members of fitness facilities. 0% 20% 40% 60% 80% 100% toilet facilities screening and fitness assessment locker / change room facilities food and beverage facilities swimming pool childcare area retail shop squash courts physiotherapy rehabilitation centre sports medicine clinic tennis courts indoor track climbing walls fig. 4. facilities offered to members of fitness facilities.fig. 4. facilities offered to members of fitness facilities. 2 0% 20% 40% 60% 80% 100% exercise mats free weights cardiovascular equipment mechanical resistance equipment group exercise studios steps and platforms stability balls balance equipment boxing equipment fig. 3. equipment available to members of fitness facilities. 0% 20% 40% 60% 80% 100% toilet facilities screening and fitness assessment locker / change room facilities food and beverage facilities swimming pool childcare area retail shop squash courts physiotherapy rehabilitation centre sports medicine clinic tennis courts indoor track climbing walls fig. 4. facilities offered to members of fitness facilities. pg93-104.indd 95 9/21/06 12:29:41 pm 96 sajsm vol 18 no. 3 2006 demographics of fitness-related staff respondents were asked to provide information regarding the numbers and demographics of the fitness-related staff employed within the facility. fitness-related staff were defined as all staff members within the facility who are involved in the health and fitness aspects of the facility. examples given were biokineticists, personal trainers, fitness consultants, group fitness instructors and floor supervisors. the average number of part-time fitness-related staff ranged from 2 in single-purpose fitness centres, to 7 in college/university fitness centres (specialist facilities). in multipurpose fitness centres, the average number of parttime fitness-related staff was 3, and in group exercise studios the average number was 4. regarding the ratio of personal and group fitness trainers in facilities sampled, multipurpose fitness centres had the highest ratio of members to trainers, with 872 members to each personal trainer, and 582 members to each group fitness trainer. group exercise studios had a ratio of 236 members to each personal trainer, and 157 members to each group fitness trainer. single-purpose fitness centres had a lower ratio of 127 members to each personal trainer, and a ratio of 159 members to each group fitness trainer. information regarding the demographics of fitness-related staff employed within the 442 facilities is presented in figs 6 and 7. the majority of fitness-related staff were young (18 25 years) white people. sixty-one per cent of the staff were male. less than 1% of the fitness-related staff were physically disabled. qualifications of fitness-related staff twenty-one per cent of the total fitness-related staff (both part-time and fulltime) hold university qualifications either in biokinetics (11%) or exercise, sports or human movement science (10%). sixty-seven per cent of the staff were qualified in first aid and 73% were qualified in cardiopulmonary resuscitation (cpr). fig. 8 presents the number of staff with diplomas aligned and not aligned with the national qualifications framework (nqf). eighty-two per cent of the various types of instructors (aerobics, spinning, step class, pilates/ stretch and tone, yoga and pezzi ball instructors) hold nqfaligned diplomas. all facilities falling under the category of gym chains, i.e. more than one club under the same name (n = 88), reported submitting a tourism, hospitality and sport education and training authority (theta) skills levy plan and claimed to have benefited from theta’s skills levy process. of the other facilities (n = 354), i.e. independent facilities, informal facilities and specialist facilities, only 89 (25%) reported familiarity fig. 5. classes and programmes available to members of fitness facilities. 0% 10% 20% 30% 40% 50% 60% 70% smoking cessation programme meditation classes lifestyle coaching / stress management classes nutrition boot camp classes sport-specific training programme special populations weight management programme aqua aerobics classes group running / walking classes dance classes yoga classes cycling / spinning classes cardio-kickboxing classes step classes stability ball-based classes pilates classes aerobics classes stretch and tone classes personal training fig. 6. racial distribution of fitness-related staff. 3 0% 10% 20% 30% 40% 50% 60% 70% pers onal training stretch and tone clas s es aerobics clas s es pilates clas s es stability ball-bas ed clas s es step clas s es cardio-kickboxing clas s es cycling / s pinning clas s es yoga clas s es dance clas s es group running / walking clas s es aqua aerobics clas s es w eight management programme special populations sport-s pecific training programme boot camp clas s es nutrition lifes tyle coaching / s tres s management clas s es m editation clas s es smoking ces s ation programme fig. 5. classes and programmes available to members of fitness facilities. 41% 14% 5% 2% 33% 4% 1% white male african male coloured male indian male white female african female coloured female fig. 6. racial distribution of fitness-related staff. fig. 7. age distribution of fitness-related staff. 4 fitness-related male staff 55% 26% 16% 3% 18 25 years 26 30 years 31 40 years 41 50 years fitness-related female staff 49% 25% 19% 7% 18 25 years 26 30 years 31 40 years 41 50 years fig. 7. age distribution of fitness-related staff. 0 50 100 150 200 250 300 350 400 450 a e ro b ic s (i n c lu d in g a q u a ) in st ru c to rs s p in n in g in st ru c to rs s te p c la ss in st ru c to rs p il a te s / s tr e tc h a n d t o n e in st ru c to rs y o g a in st ru c to rs p e z z i b a ll c la ss i n st ru c to rs nqf aligned diplomas non-nqf aligned diplomas fig. 8. number of staff with nqf-aligned and non-aligned diploma qualifications. 4 fitness-related male staff 55% 26% 16% 3% 18 25 years 26 30 years 31 40 years 41 50 years fitness-related female staff 49% 25% 19% 7% 18 25 years 26 30 years 31 40 years 41 50 years fig. 7. age distribution of fitness-related staff. 0 50 100 150 200 250 300 350 400 450 a e ro b ic s (i n c lu d in g a q u a ) in st ru c to rs s p in n in g in st ru c to rs s te p c la ss in st ru c to rs p il a te s / s tr e tc h a n d t o n e in st ru c to rs y o g a in st ru c to rs p e z z i b a ll c la ss i n st ru c to rs nqf aligned diplomas non-nqf aligned diplomas fig. 8. number of staff with nqf-aligned and non-aligned diploma qualifications. pg93-104.indd 96 9/21/06 12:29:45 pm pg93-104.indd 97 9/21/06 12:29:46 pm pg93-104.indd 98 9/21/06 12:29:46 pm sajsm vol 18 no. 3 2006 99 with theta’s skills levy plan. only 28 (8%) of these facilities submit an annual skills levy plan to theta, and only 18 (5%) claimed to have benefited from theta’s skills levy process. similar discrepancies were evident between gym chain and other facilities (independent facilities, informal facilities and specialist facilities) in the area of continuing education. all gym chain facilities (100%) stated continuing education as a requirement of fitness-related staff compared with 49% of other facilities. all gym chain facilities reported providing continuing education workshops to fitness-related staff, compared with 35% of other facilities, and the average number of continuing education workshops that staff should attend per year was 9 for gym chains as opposed to 4 in other facilities. skills shortage in the fitness industry respondents were asked an open-ended question about where they felt the greatest skills shortage lies in the fitness industry. a large portion of the responses referred to the education and training of staff, and the importance of qualification was emphasised. some also stressed the importance of interpersonal (people) skills. although not related to skills necessarily, some other issues were raised, including the importance of nutrition and the need for nutritionists, the need for facilities (size or type of facilities not specified), the public’s lack of education about and awareness of physical activity and the need for healthy lifestyles, and the importance of regulation of the fitness industry. the most valuable type of employee within the fitness industry in another open-ended question, respondents were asked to identify the type of person, along with qualifications, who would be the most valuable employee in the fitness industry at present. in their responses there was a strong emphasis on the people skills and personality aspects of employees. some of the personal qualities mentioned included enthusiasm, a passion for their work, and the ability to motivate and communicate with others. personal qualities related more to the work ethic of employees, including commitment, reliability and dedication. within the responses to this second question the importance of qualification was once again emphasised, and some specific qualifications were mentioned as valuable in the industry. these included training in biokinetics, exercise, sports and human movement science, as well as personal training. in addition to this, training in areas such as sales, marketing, finance, business and general management were also thought to be important aspects of a valued employee of the health and fitness industry. discussion from the results provided it is evident that independent facilities, which include multiand single-purpose fitness centres, studios, etc., are most dominant in the industry, and that the fitness industry is broader than traditional gym and health clubs. the relatively small proportion of gym chains is not unique to south africa, and in the usa, for example, gym chains comprise only 17% of the market. 4 the statistics presented in this article should help to establish some useful standards for the south african fitness industry, but need to be considered in the context of international standards in order to establish how south africa compares, particularly with regard to member numbers, average number of members per square meter, staff numbers and staff training. in the area of number of members as a percentage of the total population (penetration rate), south africa has a percentage close to that of countries such as mexico (1.7%) and chile (1.9%), but is far behind developed countries such as australia (8%) and the usa (14%). 3 comparing standards around staff numbers and training is, however, not as simple, as ihrsa’s research tends to focus more on the economic aspects of staffing, and does not address staff qualifications and training. information on staff in south african fitness facilities should, however, still be gathered, as standards on the ratios of staff to members may help to identify opportunities within the south african market. further research would be required to assess the number of members who require or would choose the services of a personal trainer, as well as the number of members actually attending the various types of group fitness sessions. fig. 8. number of staff with nqf-aligned and non-aligned diploma qualifications. 4 fitness-related male staff 55% 26% 16% 3% 18 25 years 26 30 years 31 40 years 41 50 years fitness-related female staff 49% 25% 19% 7% 18 25 years 26 30 years 31 40 years 41 50 years fig. 7. age distribution of fitness-related staff. 0 50 100 150 200 250 300 350 400 450 a e ro b ic s (i n c lu d in g a q u a ) in st ru c to rs s p in n in g in st ru c to rs s te p c la ss in st ru c to rs p il a te s / s tr e tc h a n d t o n e in st ru c to rs y o g a in st ru c to rs p e z z i b a ll c la ss i n st ru c to rs nqf aligned diplomas non-nqf aligned diplomas fig. 8. number of staff with nqf-aligned and non-aligned diploma qualifications. pg93-104.indd 99 9/21/06 12:29:47 pm 100 sajsm vol 18 no. 3 2006 with regard to screening and fitness assessment offered to members, it is encouraging to note that a large percentage of facilities are offering this service (compared with 89% of usa facilities 3 ) as the outcome of this type of assessment provides fitness-related staff with an indication of the level of members’ fitness as well as the presence of potential health risks. however, it may be necessary to take a closer look at these assessments in order to determine whether facilities are complying with the minimum standards of screening as prescribed by the american college of sports medicine. 1 related to this is the number of fitness-related staff with university qualifications, and this links to the sports medicine and rehabilitation services being offered at facilities. if these numbers were to be increased it would mean that more facilities could offer such services, therefore enabling facilities to be better equipped to offer programmes to special populations, such as those suffering from a particular disease or condition. what is the value of assessing the state of the fitness industry? from the health sector perspective the fitness industry has a major role to play within the government’s initiatives encouraging physical activity and healthy lifestyles, and those driving government initiatives need upto-date information on the part the fitness industry is playing. they could use this project on an ongoing basis to assess the changes in physical activity in south africans, e.g. what type of physical activity people are choosing to do, are gym memberships increasing, what are the trends in services and programmes offered, which aspects of the industry are growing? it would also be interesting to match these trends against south african and international media’s health messages around physical activity and nutrition. tracking these trends would also help to identify what types of facilities are sustainable over the long term. information on trends in the fitness industry can also help those driving government initiatives to tailor their recommendations, identify where their efforts should be placed and where support needs to be provided. in addition to this, the government’s promotion of physical activity should help to increase the exercising population in south africa, thereby creating opportunities within the fitness industry and identifying areas in which the government could provide or increase support. ongoing research would therefore help to track the influence of this initiative on the growth of the industry, both in terms of the numbers of people exercising and the facilities and services that are being offered. although there is worldwide recognition among key players in the international fitness industry that this industry has a major role to play in promoting healthy lifestyles, not all markets have seen a measurable increase in their penetration rate. 3 the usa, for example, has had a penetration rate of 14% for both 2003 and 2004, compared with 14.1% in 2002. however, brazil, with a slightly lower penetration rate than south africa, has experienced an 8% growth in its fitness industry from 2003 to 2004, and this growth is partly attributed to the public’s heightened awareness of the need to lead healthy lifestyles. 3 similar growth in the south african fitness industry is therefore conceivable in light of the government initiatives currently promoting physical activity. from the industry perspective research into the fitness industry would allow for the assessment of the shortfalls of the industry against the needs of members and communities, and through the identification of these shortfalls, opportunities would be created. one area of opportunity already mentioned is in the informal sector of the fitness industry, and this relates to the affordability of joining a fitness facility. the fitness industry needs to work on developing services that are suitable for certain areas where people are not able to afford gym fees but need to exercise. research into the fitness industry would also help to quantify the industry. by measuring its scope and size, greater confidence would be brought into the industry, and this in turn could result in increased funding opportunities. this would ultimately have a positive impact on the growth of the industry, and its credibility would be increased through the provision of formalised information. regarding developments within the south african fitness industry, a process has recently been initiated by key players in the industry to investigate the formation of a fitness industry body in south africa, along the lines of ihrsa, in other parts of the world. however, ihrsa does not yet have affiliations to other countries in africa, and south africa would have to link with either the asia-pacific or the european market. russia, classified by ihrsa as an emerging european market, has a penetration rate similar to south africa’s (1.8%), and could possibly be compared with south africa on account of the economic and political changes that have characterised the country’s recent history. 5 it has been argued that an increased interest in fitness in russia has led to increased investor interest in the industry, 3 boding well for the growth of the russian fitness market, and highlighting the possibility of similar growth of fitness industries in other developing countries. from an education and training perspective the importance of both basic and continuing education has been highlighted, and these are fundamental to the future success of the fitness industry in south africa. what has emerged confirms the need for continuing education and training for this industry, and ongoing research would help to monitor trends in education and training. ongoing research pg93-104.indd 100 9/21/06 12:29:47 pm pg93-104.indd 101 9/21/06 12:29:47 pm 102 sajsm vol 18 no. 3 2006 into the fitness industry, which falls under the sub-sector of ‘sport, recreation and fitness’ within theta, is a vital means of providing data for the development of their strategic document, the sector skills plan. 10 furthermore, having a better understanding of the industry would assist theta in the decisions they make regarding education and training in this sub-sector, enabling them to improve standards of education and training, and ultimately increase the credibility of the fitness industry. regarding the certification of fitness-related staff, it is encouraging that the numbers of staff with nqf-aligned diplomas are greater than those with non-nqf-aligned diplomas, but the aim should be to ensure that all staff members have nqf-aligned qualifications in their field. figures presented highlight the importance of the regulation of training within the industry, which is already being addressed by theta. compared with other countries worldwide, south africa, through theta and other education and training regulating structures, has made significant progress in the area of regulating the fitness industry, specifically in respect of the certification of fitness-related staff and accreditation of training sites. based on the results around awareness of theta’s skills levy process, it is clear that more attention needs to be paid to educating fitness facilities about this process and the ways in which facilities can benefit from it. work still needs to be done in the area of continuing education in facilities other than gym chains, as well as in the area of the registration of fitness-related staff. it is quite likely that a formalised registration process for fitness-related staff could result in closer monitoring of the continued education of staff, such as is the case with health professionals and the continuing professional development points system. overseeing the process of certification, accreditation and registration within the industry would need to be the responsibility of an industry body in south africa. gaps in this project and future research this project is the first of its kind undertaken in south africa, so while progress has been made in setting up a database of fitness facilities, there are understandably gaps in this database, both in terms of the facilities included and the information gathered from facilities. doing this type of research on an annual basis would help to refine the database and therefore better monitor the industry, create accurate and helpful industry benchmarks and provide useful information for the public and those with a vested interest in the fitness industry. in terms of gaps in this project, facilities in community settings are not well represented as they proved difficult to contact, and the fact that there is no formal means of communication with them further highlights the need to include them in this type of research. these types of facilities need to be included so that a larger spectrum of socioeconomic status can be represented, and if such facilities do not exist, then this is an area to be addressed. other areas that could be investigated include membership agreements and membership fees at facilities in order to determine south african benchmarks. such benchmarks would then help to gain insight into the type of commitment members are making and how affordable it is to join a fitness facility in south africa. membership retention and attrition rates, as well as member demographics, could also have been investigated, although the success of these types of investigations would rely on whether or not facilities have records on this information. other financial aspects of the industry could also be explored, such as facility revenue and total revenue of the industry, industry revenue growth, wage rates for employees, and staffing costs. from identifying the location of facilities, it is evident that the majority of facilities are in urban areas. there are clear gaps in rural and less urbanised areas, and future research would need to explore the reasons for these gaps so that they can be addressed where possible. it would be important to establish what types of facilities would be most suitable in these types of areas in terms of what would be successful and sustainable both from the business perspective as well as the health perspective. unfortunately the present set of data does not give much guidance on this as there was no dominance of a particular type of facility in rural areas – a range of facilities were present in these areas. there is also a lack of facilities in certain provinces, and further research needs to establish why this is the case – have attempts been made in the past and have they been unsuccessful? in the future, a more detailed geocoding process could be used to obtain a better understanding of the areas in which facilities are placed, in terms of the distribution of socio-economic conditions and rural versus urban areas. further research would help to establish how staff and member demographics link to distribution of facilities around south africa, and it is possible that the high number of white employees could be linked to the abundance of facilities in urban areas. from a human resources perspective, information on the staff within the industry helps to identify where there are gaps, and this information could start off the process of addressing these gaps. in a country promoting transformation, redress and equity, this should be seen as a priority. ongoing research would also be able to track any changes in the percentages of certain racial groups that are not well represented and could also help to identify some of the reasons why this is the case. conclusion future research that covers the information mentioned above, along with the type of information already gathered in this project, would have widespread benefits. ongoing research could no doubt contribute to the credibility and growth of south africa’s fitness industry, but also identify opportunities and areas in need of attention in the industry. south africa faces the challenge of increasing the nation’s physical activpg93-104.indd 102 9/21/06 12:29:47 pm pg93-104.indd 103 9/21/06 12:29:48 pm 104 sajsm vol 18 no. 3 2006 ity, and the fitness industry certainly needs to be part of rising to this challenge, particularly in the face of chronic diseases that could and do threaten the health of south africans. acknowledgements the research team would like to thank bianca meuer for her assistance in identifying facilities. funding for this research was provided by theta. these findings were presented at the 4th annual discovery vitality fitness convention (4 – 6 may 2006, vodaworld, johannesburg) by prof. tim noakes, discovery health chair of exercise and sports science, university of cape town. references 1. american college of sports medicine. acsm’s guidelines for exercise testing and prescription (7th ed). philadelphia: lippincott williams & wilkins, 2006. 2. health systems trust. health statistics: population density (accessed 2006, may 22). available from: http:www.hst.org.za/healthstats/20/data 3. international health, racquet and sportsclub association. ihrsa global report: state of the health club industry 2005. boston, ma: international health, racquet and sportsclub association, 2005. 4. international health, racquet and sportsclub association. profiles of success 2005: ihrsa’s industry data survey of the health and fitness club industry. boston, ma: international health, racquet and sportsclub association, 2005. 5. international health, racquet and sportsclub association. the ihrsa 2006 european market report: the size and scope of the health club industry. boston, ma: international health, racquet and sportsclub association, 2006. 6. kruger hs, puoane t, senekal m, van der merwe mt. obesity in south africa: challenges for government and health professionals. public health nutr 2005; 8: 491-500. 7. senekal m, steyn np, nel jh. factors associated with overweight/obesity in economically active south african populations. ethn dis 2003; 13: 109-16. 8. sparling pb, owen n, lambert ev, haskell wl. promoting physical activity: the new imperative for public health. health educ res 2000; 15: 367-76. 9. statistics south africa. mid-year population estimates, south africa 2005 (accessed 2006, may 22). available from: http://www.statssa.gov.za/publications/p0302/p03022005.pdf 10. theta. sector skills plan. (accessed 2006, june 29). available from: http://www.theta.org.za/skills/index.asp?thepage=sector_skills.htm 11. walker ar, adam f, walker bf. world pandemic of obesity: the situation in southern african populations. public health 2001; 115: 368-72. 12. walker ar, walker bf, segal i. some puzzling situations in the onset, occurrence and future of coronary heart disease in developed and developing populations, particularly such in sub-saharan africa. j r soc health 2004; 124: 40-6. 13. world health organisation. world health report 2002: reducing risks, promoting healthy life (accessed 2006, may 23). available from: http:// www.who.int/whr/2002/en/index.html 14. world health organisation. world health report 2003: shaping the future (accessed 2006, may 23). available from: http://www.who.int/whr/2003/en/ index.html 15. world health organisation. global strategy on diet, physical activity and health (endorsed by the may 2004 world health assembly) (accessed 2006, may 23). available from: http://www.who.int/dietphysicalactivity/en/ price: r380.00sa medical association, health & medical publishing group private bag x1, pinelands, 7430 tel: 021-6578200 • fax: 021-6834509 e-mail: carmena@hmpg.co.za or brents@hmpg.co.za order n ow! price: r500.00 sama price: r450.00 clinical med ad.indd 1 8/8/06 12:17:24 pm pg93-104.indd 104 9/21/06 12:29:49 pm original research 43 sajsm vol. 28 no. 2 2016 concussion return-to-play behaviour of south african rugby union (sa rugby) youth week players: a pilot study j brown,1,2 phd; k malloch-brown, 1 bsc (med)(hons) biokinetics, w viljoen,1,3 phd, cscs, c readhead, 1,3 bsc physiotherapy, s mc fie,1 bsc (hons), neuroscience 1 division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, cape town, south africa; 2 department of public & occupational health and the emgo institute for health and care research, vu university medical center, amsterdam, the netherlands. 3 south african rugby union, saru house, plattekloof, 163 uys krige road, cape town, south africa corresponding author: j brown (jamesbrown06@gmail.com) rugby union (‘rugby’) players are at a high risk of sustaining injuries, including concussion. [1] concussion is a brain injury that is defined as “a complex pathophysiological process affecting the brain, induced by biomechanical forces”, and is an “evolving injury in the acute phase with rapidly changing clinical signs and symptoms”. [1] moreover, youth athletes are more susceptible to concussion and its effects. [1] as a result, world rugby has published concussion management guidelines, to which all rugby-playing nations need to adhere (http://playerwelfare.worldrugby.org/concussion). boksmart is south africa’s national rugby safety programme. since 2011, it has been compulsory for all south african coaches and referees to attend a biennial boksmart workshop. [2] workshops include concussion education and provide attendees with free concussion resources (dvds, manual, information pieces and a pocket-sized on-field ‘concussion guide’). additional concussion information is available online: www.boksmart.com/concussion. included in all educational material is the graduated return-to-play (grtp) protocol, which is based on the consensus statement for concussion in sport [1] and world rugby’s rules and regulations. all formats emphasise the importance of being cleared by a medical doctor before returning to play. at the 2011-2014 annual sa rugby youth week tournaments, concussion comprised 31% of all time-loss injuries at a rate of 6.8/1000 player exposure hours. [3] of those players, only 14% (n=7 of 50) received any follow-up treatment before returning to play. [4] the authors suggested that a lack of medical insurance might explain this finding. [4] however, a study of youth rugby in australia found similarly low levels of compliance to grtp guidelines suggesting that this might not be a unique problem. [5] although both studies speculated as to why players did not follow grtp guidelines, to these authors’ knowledge no study has explored this further. therefore the aim of this pilot study was to explore the reasons why players did not adhere to the guideline requiring medical clearance before returning to play. methods as part of an ongoing project, injury surveillance was conducted at four sa rugby youth week tournaments in 2014 and 2015: craven week under-13, grant khomo under16, academy week under-18, and craven week under-18. as previously mentioned, [4] a tournament medical doctor was available at each tournament to assess and diagnose all tournament-sustained injuries. players with a “time-loss” injury (an injury resulting in more than one missed training/matches) were followed up telephonically until they returned to play. [4] only players with concussions were included in the present analysis (n=40). the players’ parents/legal guardians provided written informed consent to record and analyse the data. sa rugby and the uct human research ethics committee (hrec ref: 438/2011) granted permission to analyse the concussion data captured on the sa rugby database. forty concussions were recorded over the two years’ tournaments. owing to the small sample size and no outcome differences between 2014 and 2015, the data were grouped for analysis. eight of these injuries (20%) could not be followed up for various reasons, including the injured player/legal introduction: boksmart has disseminated graduated return-to-play (grtp) guidelines for concussions management to all, but specifically coaches, in south africa. medical clearance before returning to play (rtp) is poorly adhered to in the grtp steps. this study explored barriers to compliance with medical clearance prior to rtp. methods: players who suffered a concussion during the 2014/2015 south african rugby youth week tournaments were followed-up telephonically until rtp. semi-structured interviews were conducted to explore enablers/barriers to seeking/not seeking medical clearance before rtp. results: of those who did not seek medical clearance (47%), 80% indicated that the player/parent or coach felt this was unnecessary. of those who did seek medical clearance, 65% reported they were instructed to do so either by the tournament doctor who diagnosed the injury or by the school coach. conclusion: besides coaches, parents and medical doctors have an important influence on players’ rtp behaviour. the findings of this pilot study need to be repeated in a larger cohort. keywords: injury management, head injury, youth, football, south africa s afr j sports med 2016;28(2):43-45. doi: 10.17159/2078-516x/2016/v28i2a1311 http://dx.doi.org/10.17159/2078-516x/2016/v28i2a1311 original research sajsm vol. 28 no. 2 2016 44 guardian being unreachable. a university of cape town (uct) researcher performed semi-structured telephonic interviews with the players’ parents/legal guardians (n=23, 72%), and, in exceptional cases, with the players themselves when the parents/legal guardians were not contactable (n=9, 28%). the interview aimed to explore reasons for compliance or non-compliance, to seeking medical clearance before returning to play after the tournament. sm, kmb, and jb compiled the questionnaire, which was reviewed by several sport scientists, rugby medical practitioners, and sa rugby’s medical department. the questions probed whether the injured player had medical insurance and if they had had any previous experiences with concussions. they were then asked if the player had received medical clearance before returning to play. depending on the answer, they were questioned on why they did or did not seek medical clearance. for ease of recording, the interviewer had nine categories for the reasons provided. the respondents were never prompted. if the reason provided did not fall within the nine categories, it was captured as “other”. code categorisation was repeated twice by kmb and once by jb to ensure sufficient reliability. frequencies were calculated to identify the most common barriers to compliance. chi-squared tests with fisher’s exact were performed to assess if frequencies were significantly different (p<0.05) between those who did or did not seek medical clearance before returning to play. results the majority of concussed players analysed (53%, n=17) sought medical clearance before returning to play. although the number of players without medical insurance was small, there were no differences in the proportion of players seeking medical clearance, between those with and without medical insurance (without medical insurance: 50%, n=3; with medical insurance: 54%, n=14; p=0.61). similarly, previous history of concussion was not associated with seeking medical clearance before returning to play (without a previous history of concussion: 57%, n=12; with a previous history of concussion: 46%, n=5; p=0.40). the most commonly mentioned barrier to seeking medical clearance before returning to play was the perception that it “was not necessary” (80%, n=12, table 1). in the majority of cases (92%, n=11) a parent or player decided that it was unnecessary. in one of these cases, the parent’s interpretation of only the tournament medical doctor’s advice was a three week break from contact sport, but not subsequent medical clearance before returning to play. however, the accuracy of this report could not be confirmed. other reasons mentioned included being unaware of the requirement to seek medical clearance before returning to play (13%, n=2) or that it took too much time to see a medical doctor (7%, n=1, table 1). in contrast, the most frequently mentioned enabler for seeking medical clearance was because they had been instructed to do so – either by the tournament doctor (91%, n=10) or their school coach (9%, n=1). the other reasons for seeking medical clearance was because there was concern for the player’s well-being as they were still symptomatic. discussion roughly half of the concussed players in this study (53%) sought medical clearance before returning to play, which is more than in a similar study in australian youth rugby. [5] however, these two studies are not directly comparable. the australian study [5] had far greater statistical power and examined compliance to the entire grtp, whereas the present study only focused on one aspect of the grtp i.e. medical clearance prior to return to play. in this study, it is important to note that 35% of these players sought medical clearance because they were symptomatic, which is a positive. a legitimate concern, however, is that an apparently asymptomatic player, who chooses not to seek medical clearance, might not have completely recovered and may still be at risk if returned to full contact rugby too early. for example, once these players are subjected to physical exertion, symptoms might re-emerge. [1] nonetheless, the majority (65%) of players who sought medical clearance were told to do so either by the tournament doctor or their school coach. seeking medical clearance was not associated with medical insurance or previous concussion history, which is surprising, but this should be interpreted with caution due to the low sample size of this pilot study. despite these low numbers, it is concerning that the main reason cited for not seeking medical clearance was that the parents/player or school coach decided it was unnecessary. although coaches are directly targeted by the boksmart rugby safety workshops because of their influence on table 1: reasons for seeking or not seeking medical clearance before returning to play reasons for not seeking medical clearance (47%, n=15) % (n) 1 .not necessary, according to: 80 (12/15) parents/player* 92 (11/12) school coach 8 (1/12) 2. unaware of the requirement 13 (2/15) 3. too much time 7 (1/15) reasons for seeking medical clearance (53%, n=17) 1. instructed to do so, by: 65 (11/17) tournament doctor 91 (10/11) school coach 9 (1/11) 2. concern for player’s well-being (symptomatic) 35 (6/17) *in one case, the parent’s interpretation of the tournament doctor’s advice was three weeks of break from contact sport, but not subsequent medical clearance before returning to play. original research 45 sajsm vol. 28 no. 2 2016 players’ injury prevention practices, [4] they did not appear to be positively influential in this pilot sample examining concussion return-to-play behaviours. the current findings therefore suggest that additional concussion education strategies are required to effectively target medical doctors, players and parents, in addition to coaches and referees. [2] the enablers to seeking medical clearance (table 1) suggest that the tournament medical doctors who initially diagnosed the concussion are influential in determining return-to-play behaviour. thus medical doctors who regularly assess sport-related concussions might require tailored concussion education. acknowledgements: the researchers would like to thank the tournament medical doctors, nurses and paramedical staff at all the sa rugby youth week tournaments for their assistance in collecting these data. in addition, the researchers would like to thank the players and parents involved in collecting these data. conflict of interest: the authors have no conflict of interests to declare. references 1. mccrory p, meeuwisse wh, aubry m, et al. consensus statement on concussion in sport: the 4th international conference on concussion in sport held in zurich, november 2012. br j sports med 2013;47(5):250–258. [http://dx.doi.org/10.1136/bjsports-2013-092313] [pmid: 23479479] 2. viljoen w, patricios j. boksmart implementing a national rugby safety programme. br j sports med 2012;46(10):692–693. [http://dx.doi.org/10.1136/bjsports-2012-091278][pmid: 22611147] 3. mcfie s, brown j, hendricks s, et al. incidence and factors associated with concussion injuries at the 2011 to 2014 south african rugby union youth week tournaments. clin j sport med; published ahead of print post author corrections: december 22, 2015. [http://dx.doi.org/10.1097/jsm.0000000000000276] 4. brown jc, viljoen w, lambert mi, et al. the economic burden of time-loss injuries to youth players participating in week-long rugby union tournaments. j sci med sport 2015;18(4):394-399. [http://dx.doi.org/10.1016/j.jsams.2014.06.015] [pmid: 25138043] 5. hollis sj, stevenson mr, mcintosh as, et al. compliance with return-toplay regulations following concussion in australian schoolboy and community rugby union players. br j sports med 2012;46(10):735–740. [http://dx.doi.org/10.1136/bjsm.2011.085332] [pmid: 21705397] sajsm 595 (commentarty).indd commentary 1 sajsm vol. 35 no. 1 2023 creative commons attribution 4.0 (cc by 4.0) international license darkness stopping play? an update on cricket and mental health t mccabe,1 mbchb; r mccrea-routray,2 mbchb 1 nhs greater glasgow and clyde, university of glasgow, scotland 2 chief medical officer, cricket scotland, edinburgh, scotland corresponding author: t mccabe (thomas.mccabe5@ggc.scot.nhs.uk) optimisation and awareness of mental health within cricketing populations has come into greater focus of late, in part due to campaigns and educational programmes provided by leading administrations and charities working within the game. [1] there has also been a societal shift and reduction in stigma with softening of attitudes toward mental health and illness following the covid-19 pandemic in which traditional support structures were compromised and in-person socialisation was not possible. given these factors, one could expect an increase in expressed psychological distress to be forthcoming. do cricketing medical support teams have the ability to respond? we examine the cricketing landscape within the medical literature and suggest how resources may be harnessed in order to meet the need. the state of play thus far, high performance cricket and other elite sport have mostly relied upon estimates by way of self-report questionnaires to describe the prevalence of mental health symptoms within given cohorts of sportspersons. [1, 2] these studies suggest some of the most well-recognised mental health symptomology, such as poor sleep, anxiety, depression and adverse alcohol use to be at a similar level to that of the general population. although diagnostic data exist within cricketing populations [2], it is unlikely that data pertaining to an enhanced epidemiological evidence base or studies examining the efficacy of specified interventions will be forthcoming in the short term. a recent editorial [3] highlighted the need for differentiation between natural fluctuations of mental state as a result of the psychological response to sporting experiences and diagnosable mental illness. in simplistic terms, cricketers may have features of heightened anxiety and low mood due to variations in form, psychological response to non-selection, and contract negotiations. in these circumstances, there may not necessarily be a need of a formal biopsychosocial formulation but rather a short period of support or informal intervention. finding the ‘right level’ of support, at the ‘right time’, therefore can be challenging and may be dependent on resources. franchise cricket outside of the international and test game, franchise cricket leagues are an established part of the competitive cricket calendar. the indian premier league is one of the most lucrative cricket leagues from a financial perspective, with other major competitions, such as cricket australia’s big bash and the english cricket boards t20 blast, all vying for the recruitment of the world’s leading players. additionally, the sa20 and uae t20 cricket leagues started in 2023 and attracted worldwide interest. competition congestion has led to some players and support staff choosing to ‘sub-specialise’ exclusively to the white ball game ahead of first-class or test cricket, with the primary driver moving towards financial gain and avoidance of burnout rather than a cricket skill-based decision. some of the world’s leading cricketers have been prominent and open in the media with regards to taking time away from the game in order to recuperate as a result of mental stress. this is not routinely reported or disclosed within other sports. there is limited research available to describe any link between contract length and mental health although, hendricks et al [1] suggests the optimal length of contract from a mental health perspective is that of two years. with elite level players frequently representing different teams on different continents in relatively short periods of time, there can be little thought given to psychological rest. players may be reliant on differing sources of support between these teams. building and the implementation of a biopsychosocial model for an individual can take more than one sitting and is dependent on trust between the player and the practitioner, which takes time to cultivate. the optimal time to consider this may not be during an intense period of competition such as can be seen in franchise tournaments. furthermore, ethical dilemmas exist in terms of communication between practitioners and a handover of care should one be required. women’s cricket women’s cricket continues to flourish with a more prominent international calendar and rapidly evolving professionalisation. the women’s big bash league (wbbl) in australia, women’s premier league (wpl) in india and the hundred in the uk currently lead the way in the women’s franchise game. growing professionalisation brings differing challenges, including increased pressure on performance, negotiation of contracts along with an increased training and playing load outside of the international and domestic cricket calendar. the effect of this has yet to be described in the literature from a qualitative perspective. sports medicine clinicians commonly address female athlete health specific mental health within elite cricket continues to be an area of focus for researchers and practitioners working within the game. support structures for psychological issues within differing administrations and franchises vary. this may lead to inconsistent practice and levels of resource allocation. elite level cricketers are exposed to stressors as a result of the congested international and domestic calendar, contract insecurity, injury and pressure to perform. within the following commentary, the authors consider the existing medical literature, franchise and women-specific challenges and suggest ways to build on existing structures in order to optimise mental health within elite-level cricket. keywords: cricket, franchise cricket, mental health, psychiatry, womens cricket s afr j sports med 2023; 35:1-2. doi: 10.17159/2078-516x/2023/v35i1a15206 https://openingupcricket.com/ https://www.nzcpa.co.nz/pd-programme.html https://www.bacp.co.uk/news/news-from-bacp/2021/8-october-attitudes-towards-mental-health-are-changing-our-research-finds/ https://www.bacp.co.uk/news/news-from-bacp/2021/8-october-attitudes-towards-mental-health-are-changing-our-research-finds/ https://www.skysports.com/cricket/news/12173/12679605/ben-stokes-england-test-captain-on-mental-health-including-his-struggle-with-anxiety-and-panic-attacks https://www.skysports.com/cricket/news/12173/12679605/ben-stokes-england-test-captain-on-mental-health-including-his-struggle-with-anxiety-and-panic-attacks https://www.smh.com.au/sport/cricket/glenn-maxwell-details-his-mental-health-demons-20200325-p54dq9.html https://www.smh.com.au/sport/cricket/glenn-maxwell-details-his-mental-health-demons-20200325-p54dq9.html http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15206 https://orcid.org/0000-0002-2775-8669 https://orcid.org/0000-0001-8895-7218 commentary sajsm vol. 35 no. 1 2023 2 aspects of care such as menstrual health, relative energy deficiency syndrome (red-s) and its relation to performance and injury. [4] within the mental health sphere, this should be similarly reflected. women are reported to have higher levels of anxiety and reported disordered eating when compared to that of males and additionally, females within contact sports appear to take longer to recover from sports related traumatic brain injuries. [4] these factors suggest the need for differing focus when targeting prevalent symptoms and may require specialist expertise when allocating support resources. getting on the front foot optimisation of mental health is a complex process, with each individual having unique experiences of psychological distress. adaptability to provide holistic care for players and staff can be challenging to achieve from an organisational perspective but it is necessary with regard to the sport's rapidly evolving requirements. we know social networks, family and friends can have a major influence on the player’s mental state which is compromised when the player is away from their home environment for extended periods of time. [5] elite teams now take this into account when considering scheduling. governing bodies and emerging high-performance structures have an onus on them to have the appropriate support in place to meet the perceived increased need for psychological expertise for professional teams and players. traditionally, players have been reliant on a reactive model of care to respond to their mental health needs. there can be large variances in practice, help-seeking behaviours, levels of mental health literacy and ultimately, health outcomes within cricketing organisations. similarly to injury of other areas of the body, identification of illness at the earliest possible stage is something which should be a primary aim. purcell et al. [6] describe a framework for achieving this in which an ecological systems model for mental health performance is explained and discussed. in order to make a sustainable impact within this field and move beyond reactive care, there is a clear need for governing body investment and sharing of best practices. conclusion in conclusion, cricket has an opportunity to build on and expand the mental health support provided for players. achieving this will require focus from all those within cricketing administrations, including franchise owners, directors of cricket, player representatives, as well as those with clinical insight. sport and exercise physicians should aim to be in a position of leadership to work alongside specialist mental health experts in developing already established practices and delivering high-quality evidence-based interventions. promoting player welfare, as well as influencing administrators of the game to prioritise mental health to achieve parity alongside that of the physical welfare should now be possible. conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: tm wrote the original draft. rmr and tm reviewed and edited subsequent drafts. both authors approved the final manuscript. references 1. hendricks s, amino n, van wyk jp, gouttenbarge v, mellalieu s, schlebusch r. inside edge prevalence and factors associated with symptoms of anxiety/depression in professional cricketers. res sports med 2022; 1(1): 1-13. [doi: 10.1080/15438627.2022.2139619] [pmid: 36284499] 2. schuring n, kerkhoffs g, gray j, gouttebarge v. the mental wellbeing of current and retired professional cricketers: an observational prospective cohort study. phys sportsmed 2017; 45(4): 463-469. [doi: 10.1080/00913847.2017.1386069] epub 2017 oct 9. [pmid: 28952405] 3. lundqvist c, jederström m, korhonen l, timpka t. nuances in key constructs need attention in research on mental health and psychiatric disorders in sports medicine. bmj open sport exerc med 2022; 8(3):e001414. [doi: 10.1136/bmjsem-2022-001414] [pmid: 3611112] 4. lin cy, casey e, herman dc, katz n, tenforde as. sex differences in common sports injuries. pm r 2018; 10(10):10731082. [doi: 10.1016/j.pmrj.2018.03.008] [pmid: 29550413] 5. sahni m, bhogal g. anxiety, depression and perceived sporting performance among professional cricket players. br j sports med 2017 may 10:bjsports-2017-097827.5. [doi: 10.1136/bjsports-2017097827.5] [pmid: 28490460] 6. purcell r, gwyther k, rice sm. mental health in elite athletes: increased awareness requires an early intervention framework to respond to athlete needs. sports med open 2019; 5(1):46. [doi: 10.1186/s40798-019-0220-1] [pmid: 31781988] editorial — special cricket edition 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license partnerships between players, practitioners and researchers: the story of three stumps and two bails in the 1700s, the wicket in cricket consisted of two stumps and a bail. then, on 23 may 1775, during a match between kent and hambledon at the london cricket club, an incident occurred that changed the wicket forever. lumpy stevens bowled three deliveries at john small, and the ball passed between the two stumps (with the bail remaining firmly intact) three times… consecutively.[1] you can just imagine the outrage from the bowling side, being denied a wicket after beating the batting side thrice! this incident led to a law change where today the wicket consists of three stumps with two bails comfortably positioned in grooves on the top. interesting, hey?! just like we need three stumps to form a wicket, we need three pillars for cricket success: the cricket player, the practitioner (such as coaches, sports scientists, biokineticists, physiotherapists, sports physicians, strength and conditioning trainers, sports coordinators, sports managers) and the researcher. these three pillars need to remain connected by the bails, i.e. good communication. researchers often formulate research questions based on recommendations from other researchers, as mentioned in published scientific papers. however, by opening the communication channels between players and their parents (in the case of minors), practitioners and researchers, we are bound to learn what the actual practical needs are. research questions such as ‘what are the batting demands in women's cricket?’, ‘how can we improve shoulder strength in cricket fast bowlers?’ and ‘how can we best manage lumbar bone stress injuries?’ are often born during conversations and discussions between players, practitioners and researchers. simultaneously, it is important for players and practitioners to engage in research, using patient and public involvement (ppi) research designs, staying current with the latest findings, with the ultimate goal of applying research in the real world. again, communication is essential between players, practitioners and researchers. players, practitioners and researchers need to form partnerships as described in our article titled ‘injury surveillance in community cricket: a new innings for south africa’ [2] and published as a state-of-the-art feature in the south african journal of physiotherapy. this article describes how a partnership between a research entity and a cricket club or high school can impactfully enhance research. the research entity has needs and challenges but also concrete benefits to offer, while the same holds true for a cricket-playing high school or cricket club. forming a partnership means the two entities get to develop a close relationship and work towards a common goal. i know that this sounds easier said than done. while marrying a research entity and a cricket club is a great idea, it does require some high-level governance. in the meantime, we need to get going on the ground, or rather, ‘pitch’, where the action happens. how do we enhance communication between players, practitioners, and researchers? we need to be in the same room and join forces during conferences, journal clubs and case discussions. author teams of academic papers need to consist of players, practitioners and researchers, and include a section where practical sense is made of the technical jargon. this special issue in the south african journal of sports medicine concerns ‘cricket and aspects related to its science, medicine, and rehabilitation’. it presents you, the reader, with a mix of valuable gems from the batting demands in women's cricket; the kinematics of bowling and its relationship with ball release speed; the management of lumbar bone stress injuries; mental health in cricket, and the career development of south african cricketers, to mention a few. this special issue is brought to you by the wits cricket research hub for science, medicine and rehabilitation and was inspired by the 2022 cricket research and practice conference. the conference's theme of ‘#gamechangingresearch’ speaks to the need for our research to be relevant and impactful, and translatable to clinical practice. similar to how this conference brought together players, practitioners and researchers from around the world, this special issue aims to disseminate research from various subject areas, neatly bundled into one edition and tied together by the glue of cricket. in cricket, the three stumps are connected by two bails. in the same way, we need to form partnerships to ensure communication between us, and ultimately use our research to inform practice and allow practice to inform our research. and although the aim of the game is to get the bails to fly, they are always placed back onto the stumps, before the game proceeds. enjoy the read. benita olivier, phd wits cricket research hub for science, medicine and rehabilitation, department of physiotherapy, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa. benita.olivier@wits.ac.za s afr j sports med 2023;35:1. doi: 10.17159/2078-516x/2023/v35i1a15822 reference 1. mukherjee a. the incident that led to the middle-stump in cricket, 2017. https://www.cricketcountry.com/articles/theincident-that-led-to-the-middle-stump-in-cricket-495539. accessed on 16 march 2023 2. olivier b, obiora ol, macmillan c, finch c. injury surveillance in community cricket: a new innings for south africa. s afr j physiother 2022, 78 (1): a1756, doi: https://doi.org/10.4102/sajp.v78i1.1756 http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15822 https://www.cricketcountry.com/articles/the-incident-that-led-to-the-middle-stump-in-cricket-495539 https://www.cricketcountry.com/articles/the-incident-that-led-to-the-middle-stump-in-cricket-495539 https://doi.org/10.4102/sajp.v78i1.1756 https://orcid.org/0000-0001-9287-8301 sajsm 517.indd original research sajsm vol. 26 no. 3 2014 73 objective. to determine the comparative proprioceptive performance of injured v. non-injured adolescent female hockey players wearing an ankle brace. methods. data were collected from 100 high school players who belonged to the highway secondary school hockey league, kwazulunatal, via voluntary parental informed consent and player assent. players completed an injury questionnaire probing the prevalence and nature of hockey injuries (march august 2013). subsequently, players completed a biodex proprioceptive test with and without an ankle brace. probability was set at p≤0.05. results. twenty-two players sustained ankle injuries within the 6-month study period (p<0.001). injured players performed similarly without bracing (right anterior posterior index (rapi) 2.8 (standard deviation (sd) 0.9); right medial lateral index (rmli) 1.9 (0.7); left anterior posterior index (lapi) 2.7 (0.9); left medial lateral index (lmli) 1.7 (0.6)) compared with bracing (rapi 2.7 (1.4); rmli 1.8 (0.6); lapi 2.6 (1.0); lmli 1.5 (0.6)) (p>0.05). however, bracing improved the ankle stability of the non-injured group (rapi 2.2 (0.8); rmli 1.5 (0.5); lapi 2.4 (0.9); rmli 1.5 (0.5)) compared with their performance without a brace (rapi 2.5 (1.0); rmli 1.8 (0.8); lapi 2.8 (1.1); lmli 1.8 (0.6)) (p<0.05). conclusion. ankle bracing did not enhance the stability of injured ankles. however, ankle bracing has an ergogenic effect that enhances the stability of healthy ankles. s afr j sm 2014;26(3):73-76. doi:10.7196/sajsm.517 comparison of the effect of semi-rigid ankle bracing on performance among injured v. non-injured adolescent female hockey players t j ellapen, phd; n acampora, bsps hons (biokinetics); s dawson, bsps hons (biokinetics); j arling, bsps hons (biokinetics); c van niekerk, bsps hons (biokinetics); h j van heerden, d phil department of biokinetics, exercise and leisure sciences, school of health science, university of kwazulu-natal, westville, south africa corresponding author: t j ellapen (tellapen1@yahoo.com) dynamic proprioception is an integral motor component of hockey.[1,2] the most common field hockey injury is inversion ankle sprains, the injury mechanism of which has been associated with poor proprioception. [1,2] poor dynamic proprioception among hockey players often leads to ankle injuries, because the proprioceptors do not send impulses to the central nervous system quickly to ensure that the efferent neurons innervate the appropriate muscles to maintain joint stability. [2,3] predisposing factors that are attributed to field hockey injuries include frequency of hockey played, rapid, repetitive rotational movements of the ankle joint, and direct physical trauma inflicted by players on each other during tackles and collisions.[2,3] the pathomechanics of the common lateral ankle sprain among hockey players is rapid, uncontrolled excessive inversion and plantar flexion of the rear foot on the tibia. [2,3] this abrupt change in kinesiology of the talocrural joint sometimes exceeds the elastic property of the static restraints of the anterior and posterior talofibular and calcaneofibular ligaments.[2,3] prophylactic ankle bracing is prescribed in the management of ankle injuries during the return of previously injured hockey players into the game. [4] the success of prophylactic ankle bracing as an effective rehabilitative device is controversial.[4-7] olmstead et al.[4] and sharpe et al. [5] suggest that ankle bracing enhances the stability of the ankle by increasing the mechanical static restraints of the anterior and post erior talofibular and calcaneofibular ligaments, which limits excessive plantar flexion, inversion and eversion.[4,5] this enhanced mechanical static restraint of the prophylactic brace serves as a protective mechanism to limit inversion ankle sprains.[4,5] however, anderson et al.[6] and bot and van mechelen[7] reported that ankle bracing reduces the functional proprioceptive ability of the ankle joint owing to the limited movement in the frontal and transverse planes. bracing limits the range of movement at the talocrural joint in the frontal and transverse planes, but increases the risk of high ankle sprains at the distal tibofibular joint, as well as fractures at the distal tibia and lateral collateral ligament sprains of the knee.[6,7] prolonged prophylactic ankle bracing decreases the neural firing of the proprioceptors, which delay the activation of the ankle evertors, resulting in recurring ankle inversion sprains.[6,7] the literature has examined the efficacy of ankle bracing on proprioception in soccer, basketball and athletic populations, with the findings being applied to hockey.[4,5] soccer, basketball and hockey share common motor skills, which require players to sprint and make sudden changes in the direction around their opponents to gain advantage play.[1] due to the similarities in motor skills among these sports and the absence of literature examining the effect of prophylactic ankle bracing on the proprioception of hockey players specifically, injured hockey players started to use these braces on their return to play.[4] the objective of this study was to determine the effect of ankle bracing on the proprioception 74 sajsm vol. 26 no. 3 2014 of injured v. non-injured adolescent female hockey players in the frontal and sagittal planes, using the biodex balance system 3. method a total of 100 adolescent female hockey players voluntarily participated in a controlled, randomised, observational pre-test posttest crossover investigation, with parental informed consent. ethical approval was obtained from the school of health science research committee, university of kwazulunatal (shsec010/13). inclusion criteria were female players who were affiliated to the highway secondary school hockey league of kwazulu-natal, within the age range of 13 16 years. five schools participate in this league, each fielding two first teams (under-14 and -16 year age divisions). each school team has 14 players, totalling 28 players per school. therefore, the total number of players in the league specific to the age strata being studied is 140 players. players were requested to indicate only hockey injuries sustained in the last 6 months (march august 2013), and not injuries contracted from other sport and/or recreational activities. forty players were excluded because they sustained injuries while participating in recreational activities and sport other than hockey. injured hockey players were not injured during data collection because data were collected after the hockey playing season, during september 2013. the sample was 71.4% representative of the total number of league players, which is higher than the 30% statistical rule of thumb needed to indicate pertinent relationships between the independent and dependent variables of the cohort.[8] an interviewer – a graduate student who was thoroughly grounded in the research protocol and fluent in english, afrikaans and isizulu – administered a question naire to all players, whereafter biodex dynamic proprioception preand post-testing occurred. the players’ history of hockey injuries was obtained by using an injury questionnaire adapted from ellapen et al.[3] and kee and seo. [9] in the current study, an injury was defined as a sensation of distress or agony that prevented the hockey player from physical activity for a minimum period of 48 h due to a specific predisposing mechanism of injury (adapted from van heerden [10]). pain was questioned because it is a discernible symptom of musculoskeletal and/or ligamentous injuries. the injury questionnaire was divided into five parts: demographic details, anatomical site of the injury, severity of the associated pain according to the kee and seo[9] pain rating scale, the type of injury symptoms (dull aching, discomfort, sharp, pins and needles, numbness, burning and radiating) and the predisposing mechanism of the injury in accordance with hagglund et al.’s [11] definition of sport injuries. hagglund et al. reported that the fundamental problem concerning international epidemiological sport investigations is the inconsistent definition of musculoskeletal injury. [11] they proposed that the prevalence of musculoskeletal injury can be established if the following has been documented: anatomical site of musculoskeletal pain, type of musculoskeletal pain sustained and severity of pain measured by a validated pain rating scale. [11] the questionnaire was translated into english, isizulu and afrikaans. biodex dynamic proprioception test after the interview, the players were randomly allocated into either a control or experimental group through the use of a table of random numbers (50 players in each). the use of control and experimental groups was to blind the identity of the ankleinjured players and to prevent bias when interpreting the proprioception results. the difference between the groups was the use of the semi-rigid prophylactic ankle brace, which was worn by the experimental group. the use of a semi-rigid ankle brace served as an acute intervention, thus creating different scenarios under which the experimental and control groups were tested. after the pretest, the participants crossed over into their respec tive groups, to complete their dynamic proprioception post-test (fig. 1). the terms ‘braced’ and ‘unbraced’ refer to the experimental group and control group, respectively. all 100 players underwent a biodex dynamic proprioception test (unilateral dynamic limits of stability) that measured their proprioception in the frontal and sagittal planes. the test lasted 60 seconds per leg (adapted from finn’s [12] protocol). during the course of this test, the stability of the balance platform was designed to become less stable, decreasing from eight-pin stability to one-pin stability. the anterior posterior index (api) measures the ankle stability in the sagittal plane, while the medial lateral index (mli) measures the frontal plane stability, with a high stability index indicating poor stability. [12] statistical analyses the cohort was described using mode, means, frequencies and percentages. data were further analysed using inferential statistics, namely χ2 tests, two-tail t-tests adjusted for equal variance and the levene’s test to assess the homogeneity variance. the χ2 statistical test compares the counts or tallies of the categorical observed and expected results. a two-tailed t-test assumes that the difference between the two means could favour either group. levene’s test is an inferential statistic used to assess the equality of variances for two groups. if the resulting p-value of levene’s test is less than the typical 0.05 value, the obtained differences in sample variances are unlikely to have occurred based on random sampling from a population with equal variances. the levene’s test indicated equal variance (p>0.05). the alpha level was set at α<0.05. results the cohort was stratified into ankle-injured and non-injured players using their injury profile. the results are presented in the pre-test post-test control group (unbraced) experimental group (braced) control group (unbraced) experimental group (braced) fig. 1. visual description of the pre-test post-test cross-over. sajsm vol. 26 no. 3 2014 75 following categories: demographic details with respect to their injury profile, anatomical site of injury, severity of the associated pain and the type of injury symptoms. the participants’ weekly training profile history was established to determine whether it was a predisposing factor to their ankle injuries. the dynamic proprioceptive results are also presented. of the 100 players, 22 sustained ankle injuries within the previous 6 months (march august 2013) (p<0.001); these players did not sustain injuries to other anatomical sites. some of the 78 players who did not sustain ankle injuries, did sustained injuries at other anatomical sites (shoulder, hand and back) that could have influenced their dynamic proprioception (which is a limitation of the study). the age, body mass and stature of the ankle-injured and non-injured players are presented in table 1. the mechanisms of the ankle injuries were colliding with another player (28%), being struck with a ball (25%) or a hockey stick (25%) and rapid rotation change in direction (22%). the kee and seo[9] pain rating scale (range 1 5) was used to determine the severity of the pain symptoms experienced when the ankle was injured. a score of 4 (severe pain) was rated the most prevalent (55%) followed by 3 (moderate pain) (36%) and 2 (mild pain) (9%). the symptoms of ankle injuries reported were swelling (30%), then sharp pain (19%), dull aching pain (18%), radiating pain (16%), pins and needles (7%) and numbness (5%) (p<0.0001). a study limitation was the lack of a comprehensive musculoskeletal injury appraisal to determine causes of the pain. the training profile of the ankle-injured and non-injured players for the previous 12 months showed comparable months of hockey played and duration per session, suggesting that these factors were not predisposing factors to injury (table 2). although there were variations in performance between the injured and non-injured players during the unbraced phase, they were not statistically significant (table 3). similarly, the braced proprioception scores varied but not significantly so, except for the non-injured players’ better right api performance (table 4). the semi-rigid ankle brace was not an effective rehabilitative device, as shown by the ankle-injured unbraced and braced performance (table 5). table 6 provides evidence that the semirigid brace is an effective ergogenic aid that enhances the proprioception of non-injured ankles. the braced perfor mance of the noninjured players was significantly better than their unbraced performance. discussion the results are discussed here with respect to injury profile, dynamic proprioception performance and demographic details. the weekly training profile is discussed within the injury profile, as a predisposing mechanism of ankle injuries. there were 22 players (22%) who sustained ankle injuries during the previous 6 months, which is similar to previous hockey table 1. demographic measures of injured and non-injured players variables, mean (sd) injured (n=22) non-injured (n=78) p-value age (years) 14.8 (1.2) 14.8 (1.1) 0.85 body mass (kg) 59.1 (8.9) 55.2 (7.0) 0.03 stature (m) 1.6 (0.05) 1.59 (0.06) 0.55 sd = standard deviation. table 2. weekly training profile of injured and non-injured players variables, mean (sd) injured (n=22) non-injured (n=78) p-value months playing hockey 8.4 (3.3) 6.8 (3.5) 0.06 sessions/week 3.6 (1.2) 3.0 (1.4) 0.05 duration/session (minutes) 114.5 (0.5) 118.4 (1.6) 0.82 sd = standard deviation. table 3. comparison of the injured v. non-injured players biodex dynamic proprioception during the unbraced phase dynamic measures, mean (sd) injured (n=22) non-injured (n=78) p-value right api 2.8 (0.9) 2.5 (1.0) 0.31 right mli 1.9 (0.7) 1.8 (0.8) 0.68 left api 2.7 (0.9) 2.8 (1.1) 0.85 left mli 1.7 (0.6) 1.8 (0.6) 0.53 sd = standard deviation; api = anterior posterior index; mli = medial lateral index. table 4. comparison of the injured v. non-injured groups biodex dynamic proprioception during the braced phase dynamic measures, mean (sd) injured (n=22) non-injured (n=78) p-value right api 2.7 (1.4) 2.5 (1.0) 0.03 right mli 1.8 (0.6) 1.8 (0.8) 0.06 left api 2.6 (1.0) 2.8 (1.1) 0.40 left mli 1.5 (0.6) 1.8 (0.6) 0.97 sd = standard deviation; api = anterior posterior index; mli = medial lateral index. table 5. comparison of the injured group’s unbraced v. braced dynamic proprioception (n=22) dynamic measures, mean (sd) unbraced braced p-value right api 2.8 (0.9) 2.7 (1.4) 0.87 right mli 1.9 (0.7) 1.8 (0.6) 0.60 left api 2.7 (0.9) 2.6 (1.0) 0.67 left mli 1.7 (0.6) 1.5 (0.6) 0.47 sd = standard deviation; api = anterior posterior index; mli = medial lateral index. 76 sajsm vol. 26 no. 3 2014 epidemiological investigations, indicating the prolific occurrence of ankle injuries.[2,3] injury profile the mechanisms of the ankle injuries were colliding with another player, being struck with a ball or a hockey stick and rapid rotation change in direction, which is comparable with the findings of naicker et al.[2] naicker et al. postulated that rapid rotational movements during play move the ankle into plantar flexion and inversion, which exceeds the plastic properties of the lateral ligaments, resulting in tearing.[2] gallagher[1] reported that hockey players often sprint (with possession of the ball), and make sudden changes in direction of movement around their opponents to gain advantage play, which increases the risk of musculoskeletal injury and pain. the injured players completed more hockey training sessions per week than non-injured players; therefore we theorise that the additional hockey training sessions per week increased their risk of injury. ellapen et al.[3] have reported that increased frequency of hockey training sessions per week increases the risk of ankle injuries. proprioceptive performance the injured and non-injured groups’ dynamic proprioceptive performance during the unbraced phase did not differ significantly and was comparable. the injured group’s braced right api was significantly higher than that of the non-injured group, suggesting that the ankle bracing did not enhance the stability of the injured ankle joint in the sagittal plane. the evidence from the braced phase suggests that semi-rigid ankle bracing does not enhance ankle proprioception, but could impair performance. hockey players who possess poor dynamic proprioception often sustain ankle injuries.[2] the comparison of the unbraced and braced dynamic proprioceptive performance of the injured group indicates no significant difference. this evidence suggests that prophylactic bracing did not improve ankle proprioception, refuting the findings of olmstead et al.[4] and sharpe et al.[5] it is postulated that the prophylactic brace did not provide adequate mechanical restraint to the weakened anterior and posterior talofibular and calcaneofibular ligaments, thereby not stabilising the ankle joint, and did not improve the neural firing and subsequent evertor activation of the injured ankle’s proprioceptors, which is similar to the theorisation of anderson et al.[6] and bot and van mechelen.[7] bracing did enhance the performance of healthy ankles, which is similar to the findings of jerosch, bocchinfuso et al. and gross et al.[13-15] this evidence suggests that ankle bracing has an ergogenic effect on healthy ankle proprioception. comparative analyses of the braced proprioceptive stability indices (api and mli) of the non-injured group falls within the age-matched proprioception normative range (0.8 2.2).[12] prophylactic ankle bracing seems to enhance the talocrural joint’s congruency and stability while simultaneously allowing functional move ment in the frontal and transverse planes. demographic measures the age and stature of the injured and noninjured players did not differ significantly, suggesting that these factors did not predispose the players to ankle injuries. however, the injured group was heavier than the noninjured group. the association of the increased body mass and occurrence of ankle injuries among hockey players has not been established in previous studies. it is theorised that the injured players became heavier during their injury period because of their inability to train. future investigations should determine the validity of this, as it poses a study limitation. conclusion our results indicated that prophylactic semi-rigid ankle bracing is not an effective rehabilitative management device for ankle injuries. however, it is an effective ergogenic aid among non-injured players. future research should be conducted among adult professional and elite players to validate the findings of this study and to better understand the ergogenic effect of semirigid ankle bracing on non-injured ankles. these findings can assist hockey coaches, players and parents to become aware of the advantages and disadvantages of wearing semi-rigid ankle braces. references 1. gallagher d. top women hockey teams visit south africa. 2010. http://www.hockeysouthafrica.com (accessed 10 august 2010). 2. naicker m, mclean m, esterhuizen tm, peters-futre em. poor peak dorsiflexor torque associated with incidence of ankle injury in elite field female hockey players. j sci med sport 2007;10(6):363-371. [http:// dx.doi.org/10.1016/j.jsams.2006.11.007] 3. ellapen tj, abrahams s, desai fa, narsigan s, van heerden hj. prevalence of musculoskeletal pain among south african female senior national hockey players. advances in rehabilitation 2011;25(2); 27-31. [http://dx.doi.org/10.2478/rehab-2013-0007] 4. olmstead lc, vela li, denegar, cr, hertel j. prophylactic ankle taping and bracing: a numbersneeded to treat and cost benefit analysis. j athl train 2004;39(1):95-100. 5. sharpe sr, knapik j, jones b. ankle braces effectively reduce the recurrence of ankle sprains among female soccer players. j athl train 1997;32(1):21-24. 6. anderson dl, sanderson dj, hennig em. the role of non-rigid ankle bracing in limiting ankle inversion. clin j sport med 1995;5(1):18-24. [http://dx.doi. org/10.1097/00042752-199501000-00004] 7. bot sdm, van mechelen w. the effect of ankle bracing on athletic performance. sports med 1999;27(3):171-178. 8. terre-blanche m, durrheim k, painter d. research in practice. cape town: university of cape town press, 2008:50. [http://dx.doi.org/10.1155/rerp] 9. kee d, seo sr. musculoskeletal disorders among nursing personnel in korea. int j ind ergon 2007;37(3):207-212. [http://dx.doi.org/10.1016/j.ergon.2006.10.020] 10. van heerden hj. pre-par ticipation evaluation and identification of aetiological risk factors in epidemiolog y of sports injuries among youths. dphil thesis. pretoria: university of pretoria, 1996. 11. hagglund m, walden m, bahr r, ekstrand j. methods for epidemiological study of injuries to professional football players: developing the uefa model. br j sports med 2005;39(6):340-346. 12. finn ja, alvarez mm, jett re, axtell rs, kemler ds. stability performance assessment among subjects of disparate balancing abilities. med sci sports exerc 1999;31(5):s252. [http://dx.doi.org/10.1097/00005768199905001-01209] 13. jerosch j. the influence of orthoses on proprioception of the ankle joint. knee surg sports traumatol arthrosc 1995;3(1):39-46. 14. bocchinfuso c, sitler mr, kimura if. effects of 2 semirigid prophylactic ankle stabilizers on speed, agility and vertical jump. j sport rehabil 1994;3(2):125-134. 15. gross mt, bradshaw mk, ventry lc, weller kh. comparison of support provided by ankle taping and semi-rigid orthosis. j orthop sports phys ther 1987;9(1):33-39. table 6. comparison of the non-injured group’s unbraced v. braced dynamic proprioception (n=78) dynamic measures, mean (sd) unbraced braced p-value right api 2.5 (1.0) 2.2 (0.8) 0.02 right mli 1.8 (0.8) 1.5 (0.5) 0.01 left api 2.8 (1.1) 2.4 (0.9) 0.04 left mli 1.8 (0.6) 1.5 (0.5) 0.01 sd = standard deviation; api = anterior posterior index; mli = medial lateral index. introduction swimming is a popular recreational and professional sport code both locally and internationally. the south african swimming team represents south africa at the olympics and other world-level competitions. to ensure that these participants and those who will replace them on the world arena can function optimally, it is essential to keep them injury-free. in order to ensure that the best conditioning programmes are developed it is important to know the incidence and other related information pertaining to injury in these athletes. the shoulder joint is the most vulnerable to injury, as has been shown in many reports. 3,6,8-11 to date very little research on the epidemiology of shoulder or other injuries in south african swimmers has been published in the scientific literature. literature from several developed countries reveals information on the incidence, 1,2,7,8 and types 1,7,8,9 of shoulder injuries as well as the effects of training 7 on shoulder injury sustained in this sport. most swimming injuries are due to repetitive microtrauma and overuse, with many of these injuries actually due to faulty technique. 10,11 repeated microtrauma and overuse strain of passive and active components of the shoulder lead to diminished performance over a period of time (overuse) and can lead to acute injury, resulting in reduced ability or an inability to participate in the sport. in both cases, professional training programmes, and sport-specific conditioning are crucial in determining whether participation and performance can be optimised. when one considers the biomechanics of the shoulder joint and the demand placed on it during each of the swimming strokes, it becomes clear that a very high level of specificity in conditioning is appropriate. the structural limitations imposed by a shallow glenoid cavity together with a large degree of motion suggest the need for balanced muscle control at all times. 13 the main power of propulsion is provided by arm action during the pull phase in all strokes, with the exception of breaststroke. 14 athletes, who use the arm for propelling, strain at the extremes of joint range in their drive for maximum performance. 13 repetitive motion at the extremes of range are supported by the stabilising structures or ‘restraint mechanisms’ which prevent excessive translation of the humeral head on the glenoid fossa. if any one of the original research article shoulder injuries in competitive swimmers in kwazulu natal t puckree (bsc physio, ms (exercise science), med, phd (exercise physiology)1 k j thomas (b physio)2 1 department of physiotherapy, university of kwazulu-natal, durban, and school of physiotherapy, sport science and optometry, university of kwazulu-natal, westville campus, durban 2 final-year physiotherapy student, department of physiotherapy, university of kwazulu-natal, durban abstract objective. to determine the incidence of shoulder injuries in competitive swimmers in kwazulu-natal, a province in south africa. design. a cross-sectional survey was conducted. a random sample of 96 swimmers from a pool of 300 swimmers registered with first-division clubs affiliated to the kwazulu-natal aquatics association participated in the study by informed voluntary consent. data were gathered using a validated questionnaire. setting. data were gathered at time trials, races and club meetings. main measures. variables monitored included the incidence of shoulder injuries, shoulder pain and proportion of overuse injury. results. seventy-one per cent of the swimmers had shoulder pain and 64% reported injury to the shoulder. forty-six per cent of the swimmers with pain complained of anterior shoulder pain, while 65% of all injuries were due to overuse. the commonest diagnoses included tendonitis (35%), muscle imbalance (29%), impingement (19%) and other (17%). sixty-nine per cent of the swimmers swam freestyle which was related to 70% of the injuries. eighty-one per cent of the injured swimmers sought physiotherapy for the shoulder pain. conclusion. the incidence of shoulder injuries in competitive swimmers is high. this study shows the need for more research into swimming injuries, and the conditioning and rehabilitation of athletes in south africa. correspondence: t puckree department of physiotherapy university of kwazulu-natal private bag x54001 durban 4000 tel: 031-260 7977/7817 fax: 031-260 8106 e-mail: puckreet@ukzn.ac.za 10 sajsm vol 18 no. 1 2006 shoulder injuries.indd 10 3/13/06 2:40:25 pm sajsm vol 18 no. 1 2006 11 mechanisms does not function properly injury will result. the rotator cuff stabilises the head of the humerus in the centre of the glenoid cavity, while the prime movers provide the power. a well-functioning rotator cuff prevents excess movement or translation of the humeral head in anterior, posterior and superior directions. fatigue of the supraspinatus muscle predisposes the shoulder to injury due to abnormal humeral movement. 11 resistance training to increase strength of the rotator cuff and the scapular stabilising muscles has been suggested to control the risk of injury 4 . the stabilising structures include passive components (ligaments, joint capsule, joint cohesion mechanism, negative intra-articular pressure) and the active component (rotator cuff). core strengthening, especially of the lower abdominal muscles, is important in supporting the trunk during arm movements. 9 a search for new scientific reports on swimming-related shoulder injuries revealed just a single publication in 2003. 9 in south africa and kwazulu-natal (kzn) the current status of the epidemiology of swimming injuries is not known. this deficit will impact on the performance of our swimmers in the international arena. in order to address this gap, the present study looked at the incidence and causes of injuries in clublevel competitive elite swimmers in kzn. methods all competitive swimmers (those who swam a qualifying time for the 2000 provincial team and achieved provincial colours) regardless of gender or race, between the ages of 13 and 25 years registered with the kzn aquatics association made up the population. from this pool of 300 swimmers, a random sample of 96 athletes were invited to participate after being fully informed and giving voluntary consent. information on participants’ personal details, medical and sporting history, training history and epidemiology of current and previous swimming-related shoulder injuries was obtained using a validated questionnaire 17 with open and closed-ended questions. the data were analysed descriptively and statistically using chi-square tests (spss version 6.0 for windows). probability was set at p < 0.05. results the response rate was 83%. eighty-one per cent of the questionnaires were usable. forty-seven per cent of the respondents were female. seventy-one per cent of the respondents experienced shoulder pain, while 64% reported actual shoulder injuries which included impingement, supraspinatus and bicipital tendonitis, bursitis and muscle strain. fifty-two per cent of the injured swimmers were male. sixty-five per cent of the injuries were due to overuse (recurrent) as opposed to traumatic injuries (25%), which is similar to the findings reported by mcmaster et al. 12 ninety-six per cent of the swimmers trained and participated in events for 11 12 months of the year. significantly more swimmers between the ages of 15 and 16 years (23%) were injured compared with 14 18% in the other age categories. sixty-nine percent of the swimmers reported swimming freestyle. the majority (70%) of the swimmers attributed their injuries to freestyle, which they swam most of the time. the majority of specialist sprinters (70%), regardless of gender, complained of shoulder injuries compared with longdistance swimmers. the average length of a training session for a kzn swimmer was 90 minutes. the training sessions were not individualised or specific, and were unsupervised. the majority of the swimmers trained twice daily on weekdays, with an average of 11 sessions per week. in addition the majority participated in resistance training programmes. seventy-seven per cent of the swimmers with shoulder injuries participated in resistance training (gym, strengthening exercises). the use of paddles during resistance training did not have any significant effect on the difference between those with and without injuries. those swimmers who reported no injury spent more time (15 minutes or more) doing stretches and warm-ups compared with 10 minutes or less by the injured swimmers. detailed information on the stretches done was not obtained in an effort to contain the length of the questionnaire. stretching was 1 component of the training programme. the commonest site of pain was the anterior shoulder (55% females and 40% males). anterior shoulder pain was attributed to supraspinatus and bicipital tendonitis. tendonitis (35%), muscle imbalance (29%) and impingement (19%) were significantly more common than bursitis, muscle strain and laxity, which combined were responsible for the remaining 17% of injuries. seventy-five per cent of the swimmers who complained of shoulder injuries had to stop swimming temporarily due to the injury. length of time away from swimming was on average 2 3 weeks. of the 52 swimmers who reported injuries, 79% received physiotherapy, which was reportedly effective for both the management and prevention of overuse injuries. no details of the specific physiotherapy modalities used were elicited. one respondent required surgical intervention for a glenohumeral joint problem. discussion sixty-five per cent of the injuries reported by elite swimmers who participated in the study were overuse (recurrent) in nature, which is similar to the findings of mcmaster et al. 12 this can be attributed to the fact that 96% of the swimmers trained and participated in events for 11 12 months of the year. therefore little time was allowed for rest or recuperation and for repair following injury. in addition, in order to be able to compete at provincial and national levels, the training schedules are extremely demanding due to the high volume, intensity, duration and frequency of training sessions. swimming injuries involve upper-limb overuse due to the magnitude of repetitive activities. 5,15 mcmaster et al. 12 estimate that if a swimmer swims an average of 10 km per day for 5 days a week and 10 months of the year, with an shoulder injuries.indd 11 3/13/06 2:40:26 pm 12 sajsm vol 18 no. 1 2006 average of 15 strokes per length of a 25 m pool, this will translate into 1 200 000 repetitive arm movements per year. the kzn swimmer undertakes more than this, as shown in the results. the fact that more swimmers between the ages of 15 and 16 years (23%) compared with the other age categories, were injured may suggest that during this period of rapid growth, adolescents are particularly vulnerable to injuries. this is partially due to an imbalance between strength and flexibility. 2 the imbalance could be in the strength between the agonists and antagonists, the relationship between flexibility and strength of the agonists and antagonists or between strength of the core stabilisers, scapular stabilisers and rotator cuff muscles which all help to stabilise during rapid mobility of the glenohumeral joint. 9 the majority of specialist sprinters (70%) regardless of gender complained of shoulder injuries compared with long-distance swimmers. this also supports the findings of richardson. 15 during a sprint, the arms turn over at a very rapid rate compared with the slower more relaxed technique employed by distance swimmers. the increased rate and speed at which the arms move overhead as well as the added power in the arm action to propel the sprinter through the water could cause repeated microtrauma to structures in the shoulder joint. freestyle is a very popular stroke amongst kzn competitive swimmers. the freestyle stroke utilises repetitive reciprocal overhead action. the majority (70%) of the swimmers attributed their injuries to freestyle, which they swam most of the time. this finding is supported by the study of richardson et al. 16 which reported a 75% incidence of shoulder injuries in freestyle swimmers. the repetitive action predisposes these swimmers to injury. the fact that the swimmers’ training requires more than 1 million overhead strokes per year increases their risk of shoulder injury. the use of stretching and warm-ups prior to training seems to be effective in controlling injury rate. stretching and warmups help to increase the range of motion, minimise incidence of musculotendinous injuries, minimise muscle soreness and reduce the risk of injury. 7 swimming is performed in a nonweight-bearing medium. 1 resistance training can increase muscular strength and reduce the incidence of overuse injuries. 4 the injures sustained by 77% of the swimmers who participated in resistance training in this study could be due to problems with the manner in which the resistance exercises were performed. therefore professional training programmes and appropriate swimming-specific supervision may help. resistance training and conditioning or rehabilitation must be sport-specific. length of time away from swimming due to injury was 2 3 weeks, which is in keeping with suggestions by baxterjones et al. 2 who reported a recovery time of 13 days or more after an injury was sustained. preventive physiotherapy or teamwork between coaches, fitness specialists, physiotherapists and physicians could help swimmers overcome the burden of overuse injuries. preventive physiotherapy should include all of the following: education on the condition; risks of the sport; motor control (in lay terms) of the shoulder action in swimming; recognition of danger signals; use of equipment; rest; balanced flexibility of the rotator cuff, scapular stabilisers, glenohumeral mobilisers and core stabilisers; strength training on land and water for the above muscle groups; core stability and endurance; cross-training for endurance and speed; and skill development through swimming-specific movement patterns. all of these will assist in adapting the muscular and neural mechanisms to optimise motor control during the sport. conclusion the results of this study show that the incidence of shoulder injuries in kzn elite swimmers is significantly high. similar to the findings of other investigators, overuse injuries predominated. this study shows the need for more research, specificity of biokinetic training and advanced levels of training and coaching to prevent or control injury rates in competitive swimmers, at least in kzn. the training programmes should include structured rest periods, cross-training that focuses on strength, endurance, speed, flexibility and co-ordination in sport-specific patterns of movement, periodisation and skill development. references 1. allegrucci m, whitney sl, irrgang jj. clinical implications of secondary impingement of the shoulder in freestyle swimmers. j orthop sports phys ther 1994; 20: 307-18. 2. baxter-jones a, maffulli n, helms p. low injury rates in elite athletes. arch dis child 1993; 68: 130-2. 3. birrer p. the shoulder, emg and the swimming stroke. j swim res 1986; 2(5): 20-3. 4. fleck sj, falkel je. value of resistance training for the reduction of sports injuries. sports med 1986; 3(1): 61-8. 5. fowler p. swimmers problems. am j sports med 1970; 2:141-4. 6. fowler pj, webster ms. shoulder pain in highly competitive swimmers. orthop trans 1983; 7(1): 170. 7. griep jf. swimmers shoulder. the influence of flexibility and weight training. orthop trans 1986; 10: 216. 8. jones jh, swimming overuse injuries. phys med rehabil clin n am 1999; 10(1): 77-94. 9. johnson jn, gauvin j, fredericson m. swimming biomechanics and injury prevention. physportsmed 2003; 31(1): 1-7. 10. kammer cs, young cc, niefeld mw. swimming injuries and illnesses. physportsmed 1999; 27(4): 51-60. 11. mcmaster wc. swimming injuries. an overview. sports med 1996; 22:332-6. 12. mcmaster w, troup jp, arredondo s. the incidence of shoulder problems in developing elite swimmers. j swim res 1989; 5(2): 11-6. 13. perry j. anatomy and biomechanics of the shoulder in throwing, swimming, gymnastics and tennis. clin j sport med 1983, 2: 247-70. 14. pettrone f. athletic injuries of the shoulder. new york: mcgraw hill, 1995. 15. richardson ar. the biomechanics of swimming: the knee and shoulder. clin j sport med 1986; 5:103-13. 16. richardson ar, jobe fw, collins hr. the shoulder in competitive swimming. am j sports med 1980; 8:159-63. 17. thomas jt. the incidence of shoulder injuries in competitive swimmers in kwazulu natal. honours thesis (physiotherapy), university of durbanwestville, 2000, appendix 7:38-41. shoulder injuries.indd 12 3/13/06 2:40:26 pm original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license effects of wearable resistance load placement on neuromuscular activity and stride kinematics: a preliminary study m brown,1,2,5 msc; c giroux,2 phd; m lacome,2,6 phd; c leduc,4 phd; k hader,3 phd; m buchheit,2,3 phd 1 paris saint germain, 5 avenue du president john fitzgerald kennedy, saint germain-en-laye, paris, france, 78100 2 french institute of sport (insep), laboratory sport, expertise and performance (ea 7370), paris, france 3 kitman labs, performance research intelligence initiative, dublin, ireland 4 carnegie applied rugby research (carr) centre, carnegie school of sport, leeds beckett university, leeds, united kingdom 5 playermaker, 35 ballards lane, london, united kingdom n3 1xw 6 parma calcio 1913, performance and analytics department, parma, italy corresponding author: m brown (matthewbrown@hotmail.co.uk) one of the keys for athletic performance is the successful transference of strength and power adaptations from gym-based exercises to sportspecific movements.[1] a practitioner’s main goal when developing a resistance training programme is to develop an athlete’s strength and power outputs.[2, 3] however, those improvements might not always transfer to on-field performance, with factors such as training methodology, volume, duration, and intensity influencing the transfer effect of training-induced strength and power adaptations.[2, 3] to alleviate those inherent limitations, wearable resistance (wr) training may be a practical solution, with a better ecological fit than traditional gym-based resistance training. wr training allows athletes to perform loaded sport-specific movements which are hypothesised to provide greater transference to sport-specific movement performance compared with traditional gym-based exercises.[1] wr has been used extensively within athletics and sprint training.[1, 4] research suggests wr can elicit increases in horizontal force production and improve sprint performance.[1, 4] additionally, investigations have explored the potential performance benefits of using wr for team sports.[5-7] one study investigating the use of calf-loaded wr during warm-ups for elite footballers reported improvements in maximal horizontal (e.g. 10and 20m sprints) but not vertical (e.g. counter movement jump) performance.[5] in rugby players, the use of calf loaded wr (1% body mass, bm) resulted in a better maintenance of acceleration and sprint performance during a six week training period compared to unloaded players.[6] furthermore, wr training increased acute training load for high school american footballers loaded with 1% bm on the calves.[7] in addition to wr training effects on locomotor performance, there is growing knowledge regarding movement kinematics and muscle coordination involved with wr loading.[1, 8] during loaded sprinting, stride length and frequency decreased, while contact time and ground reaction forces increased.[1] previous research showed that the positioning of wr impacts stride kinematics.[8]) for example, greater kinematic changes were observed for calf loaded wr conditions compared to thigh loaded wr.[1] however, it is yet to be investigated how the effect of wr varies based on lower limb load location (e.g. proximal vs distal placement, anterior vs posterior, background: wearable resistance (wr) training is a modality that allows athletes to perform loaded sport-specific movements to develop force and power outputs. the acute responses by which wr works is still relatively unknown, and the effects of wr load and location of the load has not yet been examined. objectives: to investigate the acute neuromuscular and stride characteristic responses to different wearable resistance (wr) loads and placements on the calf muscles during high-speed running. methods: ten well-trained subjects completed a workout of ten sets of three 10s runs at 18km.h-1 (20s of rest between runs and one min between sets). five conditions were tested: (1) unloaded control, (2) bilateral 0.75 vs. 1.5% body mass (bm) loading on the distal posterior calf, (3) bilateral proximal vs. distal loading of 1.5% bm positioned posteriorly, (4) bilateral anterior vs. posterior loading of 1.5% bm positioned distally, (5) unilateral loading of 1.5% bm on the distal posterior calf. data were collected using electromyography (emg) and back-mounted gps-embedded accelerometers. magnitude of differences of within athlete and between muscle comparisons were calculated using effect sizes (es) ± 90% confidence limits (cl). results: no substantial differences in accelerometry data were observed between any of the loaded conditions and the control. emg activity was lower for proximal loading compared to the control for the gluteus maximus (es±90%cl; -0.72±0.41), vastus lateralis (-0.89±0.47) and vastus medialis (vm) (-0.97±0.46). anterior loading induced substantially lower emg activity for the semitendinosus (-0.70±0.48) and vm (-0.64±0.39) muscles compared with the control. emg activity of the vm (-0.73±0.46) muscle was also substantially lower for posterior loading compared to the control. unilateral loading induced no substantial differences in emg activity between the loaded and unloaded legs. conclusion: this preliminary study has provided a rationale for the performance of further investigations into the effects of wr lower limb loading on stride characteristics and emg activity from a chronic standpoint using a larger population. keywords: stride characteristics, electromyography, accelerometry, muscle activation s afr j sports med 2022;34:1-8. doi: 10.17159/2078-516x/2022/v34i1a13102 mailto:matthewbrown@hotmail.co.uk http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13102 https://orcid.org/0000-0002-1082-0200 https://orcid.org/0000-0001-8471-6046 https://orcid.org/0000-0002-5262-2798 https://orcid.org/0000-0002-8054-546x https://orcid.org/0000-0002-5528-2039 https://orcid.org/0000-0002-2498-6340 original research sajsm vol. 34 no.1 2022 2 bilateral/unilateral). if stride mechanics were to be altered, and/or specific muscle recruitment to be modified in relation to various wr placements (potentially affecting muscle coordination), this may have important implications for the integration of wr in training practices (e.g. rehabilitation). therefore, the aims of this preliminary study were to investigate changes in muscle activation amplitude and stride characteristics induced by the effects of wr calf loading of different loads (0.75%bm vs 1.5%bm), different load placements (anterior vs posterior and proximal vs distal), unilateral loading and loaded vs unloaded conditions during high-speed running efforts. methods subjects ten well-trained male subjects (30.9±6.0yrs, 178.6±5.4cm, 75.8±5.8kg), who regularly partake in running and resistancebased training (8 hours per week) completed this study. table 1 shows the anthropometric data of the participants. subjects were free from injury and illness for at least 4 weeks prior to the start and gave their consent for data obtained to be used in this study. data collection was part of the club’s regular monitoring procedures which conformed to the declaration of helsinki.(9) intervention subjects completed a workout of ten sets of three 10s runs at 18km.h-1 with 20s rest between runs, and one min between sets. each run was performed on a motorised treadmill (skillrun unity-7000, technogym, italy). before each set, wr (lila™ exogen™, malaysia) was placed on subject’s lower limbs. five different wr conditions were tested: (1) control without load, (2) 0.75 vs 1.5% bm loading positioned on the distal posterior calf, (3) proximal vs distal loading of 1.5% bm positioned posteriorly (4) anterior vs posterior loading of 1.5% bm positioned distally, (5) unilateral loading of 1.5% bm positioned on the distal posterior calf (conditions 2-4 were bilaterally loaded). figure 1 shows the experimental wr loading patterns. data were collected using surface electromyography (emg) and an embedded accelerometer within an upper back mounted gps unit. measurements  effect of load: 0.75% or 1.5% bm loading was placed on the posterior, distal portion of the lower limbs, aligned with the gastrocnemius aponeurosis line of action (figs. 1a and b).  anterior/posterior: to assess the effect of anterior/posterior loading, a 1.5% bm load was placed distally either on the front (anterior) or rear (posterior) of the lower limbs, aligned with the tibialis anterior insertion and the gastrocnemius aponeurosis line of action respectively (figs. 1b and d).  proximal/distal: to test the effect of proximal/distal loading, a 1.5% bm load was placed posteriorly either on the upper calf (proximal) or lower calf (distal) between the origins of the medial and lateral heads of the gastrocnemius and in alignment with the gastrocnemius aponeurosis respectively (figs. 1b and c).  unilateral condition: the unilateral condition involved load placement on one leg with 1.5% bm placed on the posterior distal portion of the lower limb, aligned with the gastrocnemius aponeurosis, while the other leg was unloaded (fig.1e). participants completed the unilateral trial with both legs and this data was pooled to give an average unilateral measure.  control condition: running without additional load. table 1. individual subject anthropometric data: age, height and body mass subject age (yrs) height (cm) body mass (kg) 1 25.0 185 80.9 2 23.2 175 68.3 3 35.2 178 75.5 4 31.2 170 68.0 5 23.5 181 77.2 6 26.0 172 69.7 7 41.4 183 73.7 8 37.4 188 83.6 9 33.3 176 85.1 10 33.1 178 76.0 mean ± sd 30.9 ± 6.0 178.6 ± 5.4 75.8 ± 5.8 fig. 1. the experimental conditions – wearable resistance (wr) lower limb loading patterns. a) 0.75% bm distal, posterior loading; b) 1.5% bm distal, posterior loading; c) 1.5% bm proximal, posterior loading; d) 1.5% bm distal, anterior loading; e) 1.5% bm distal, posterior, unilateral loading. original research 3 sajsm vol. 34 no.1 2022 data collection procedures electromyography a bts freeemg 300 wireless surface emg system (bts® quincy, usa) was used with sensors placed on the gluteus maximus (gmax), bicep femoris (bf), semitendinosus (st), rectus femoris (rf), vastus lateralis (vl) and vastus medialis (vm) muscles for each leg. the skin was shaved, gently abraded and cleaned with alcohol to minimise interelectrode impedance. the bipolar, silver/silver chloride, surface disc electrodes (blue sensor n-00-s/25; ambu, baltorpbakken, denmark) were placed with a centre-to-centre distance of 2.5cm, longitudinally with respect to the underlying muscle fibre arrangement and located according to the surface emg for the non-invasive assessment of muscles (seniam) recommendations. the sampling frequency was 1000hz. the emg data processing technique started with filtering the emg signal (high pass, 15hz, third order butterworth filter). secondly, the calculation of the muscle activity (mean root mean square, rms) during each of the trials was performed. the first and last few steps were excluded from the recording window to keep only the stable phase of the run. the treadmill was continually moving with participants instructed to jump onto the side between trials. this minimised any acceleration required during each repetition in an aim to increase the stability of the runs. the mean rms for each trial was calculated. the three trials for each condition were averaged (cv: 6.1-8.8%). the control condition (mean rms) was used to normalise all other conditions. emg data is displayed as a % of the normalised condition. stride characteristics embedded accelerometers (952 hz) in gps units (statsports®, northern ireland) were used in indoor mode to calculate bilateral stride kinematics. accelerometry raw data were further analysed using adi software (athletic data innovations, sydney, australia) to derive floor contact time (ct [seconds]), peak force (newtons), stride frequency (steps/second), and vertical stiffness (kvert [kn.m-1]).(10) adiderived metrics were shown to be reliable with small to moderate error during high-speed running (standardised typical error: 0.52-0.67).(10) data analysis muscle activity and accelerometry data for bilaterally loaded conditions were calculated using the average of three repetitions per condition from both legs and normalised in relation to the control condition (%). muscle activity for the unilateral condition used the pooled average from the loaded legs (average of loaded left and right legs) to compare with the unloaded legs (average of unloaded left and right legs) to observe possible changes in muscle activation. statistical analysis data are presented as mean ± standard deviation (sd) and as effect size ± 90% confidence limits (cl). data were first checked for normality (shapiro-wilks test). log transformation was used when required to transform skewed data to approximately conform to normality. data were back transformed after analysis to return them back to original units. the athletes comparisons between muscles were made using effect sizes based on cohen’s d principle to determine the magnitude of change between conditions (0.75 vs 1.5% bm, anterior vs posterior, proximal vs distal, unilateral loading, control compared with all conditions) using hopkins scale: 0.2 (small), 0.6 (moderate), 1.2 (large), 2.0 (very large).(11) when the cl of the effect size (es) did not overlap the smallest worthwhile change (swc) (0.2), the change was considered substantial and of the observed magnitude; if the cl overlapped the swc, the change was unclear.[12] results differences between conditions for accelerometry data are presented in table 2 and differences between conditions for emg data are presented in table 3. intra-subject variations between the stride frequency data is displayed in figure 2 showing large individual responses to the load and placement. figure 3 shows the synchronisation of left and right emg data with vertical acceleration data for different loading patterns. effect of load no substantial differences were observed between 0.75% bm loading, 1.5% bm loading and the control for all stride characteristic metrics (all es rated as unclear). likewise, no substantial differences in stride characteristics were observed between 0.75% and 1.5% bm loading. emg activity for the vl and vm muscles were moderately lower for 0.75% bm loaded conditions compared with the control (es:0.63-0.92). additionally, 1.5% bm loading induced moderate decreases in emg activity of the vm compared to the control (es±90%cl; 0.70±0.44). anterior vs posterior load placement accelerometry data showed no substantial differences for all stride characteristics of the anterior and posterior conditions compared to the control (all es rated as unclear). anterior loading induced moderately lower emg activity for the st and vm muscles compared with the control (st:0.70±0.48, vm:0.64±0.39). emg activity of the vm muscle was also moderately lower for posterior loading compared to the control (0.73±0.46). no substantial differences in stride frequency were observed between anterior and posterior loading. furthermore, no substantial differences in emg activity were observed for any muscle between anterior and posterior loading (all es rated as unclear). proximal vs distal load placement proximal and distal loading conditions showed no substantial differences in stride characteristics compared with the control. moreover, accelerometry data showed no substantial differences in stride characteristics observed between proximal and distal loading (all es rated as unclear). original research sajsm vol. 34 no.1 2022 4 cfcfdfdgghd table 2. accelerometry data: bilaterally loaded conditions – 0.75% vs 1.5% body mass (bm) loading, anterior vs posterior loading, proximal vs distal loading accelerometry data mean ± sd effect size ± 90% confidence limit control 0.75% 1.50% control vs 0.75% control vs 1.5% 0.75 vs 1.5% contact time (ms) 0.17 ± 0.01 0.17 ± 0.01 0.17 ± 0.01 0.12 ± 0.28 0.11 ± 0.22 0.00 ± 0.20 peak force (n) 4 439 ± 299 4 448 ± 251 4 499 ± 232 0.04 ± 0.19 0.22 ± 0.24 0.18 ± 0.20 frequency (step/s) 2.99 ± 0.10 3.01 ± 0.15 3.07 ± 0.10 0.08 ± 0.48 0.53 ± 0.44 0.45 ± 0.43 kvert (kn.m-1) 121 ± 14.9 120 ± 15.4 121 ± 15.9 -0.09 ± 0.33 0.00 ± 0.28 0.09 ± 0.17 control anterior posterior control vs anterior control vs posterior anterior vs posterior contact time (ms) 0.17 ± 0.01 0.17 ± 0.01 0.17 ± 0.01 0.27 ± 0.75 0.12 ± 0.22 -0.15 ± 0.95 peak force (n) 4 439 ± 299 4 492 ± 231 4 499 ± 232 0.38 ± 0.50 0.23 ± 0.24 -0.09 ± 0.47 frequency (step/s) 2.99 ± 0.10 3.06 ± 0.12 3.07 ± 0.10 0.67 ± 0.50 0.59 ± 0.49 0.06 ± 0.78 kvert (kn.m-1) 121 ± 14.9 120 ± 16.3 121 ± 15.9 -0.50 ± 0.57 0.00 ± 0.27 0.07 ± 0.81 control proximal distal control vs proximal control vs distal proximal vs distal contact time (ms) 0.17 ± 0.01 0.17 ± 0.01 0.17 ± 0.01 0.17 ± 0.20 0.11 ± 0.22 -0.06 ± 0.18 peak force (n) 4 439 ± 299 4 531 ± 238 4 499 ± 232 0.34 ± 0.45 0.23 ± 0.24 -0.11 ± 0.45 frequency (step/s) 2.99 ± 0.10 3.08 ± 0.17 3.07 ± 0.10 0.60 ± 0.64 0.52 ± 0.43 -0.08 ± 0.58 kvert (kn.m-1) 121 ± 14.9 122 ± 17.7 121 ± 15.9 0.02 ±0.24 0.00 ± 0.27 -0.01 ± 0.20 frequency, stride frequency; kvert, vertical stiffness. table 3. emg data: bilaterally loaded conditions – 0.75% vs 1.5% body mass (bm) loading, anterior vs posterior loading, proximal vs distal loading emg data % normalised condition ± sd effect size ± 90% confidence limit 0.75% 1.50% 0.75% vs 1.5% control vs 0.75% control vs 1.5% bf 93 ± 36 93 ± 36 -0.04 ± 0.17 -0.34 ± 0.25 -0.38 ± 0.27 gmax 71 ± 50 71 ± 50 0.01 ± 0.31 -0.50 ± 0.46 -0.50 ± 0.39 rf 83 ± 70 75 ± 67 -0.09 ± 0.24 -0.34 ± 0.29 -0.42 ± 0.33 st 87 ± 31 80 ± 33 -0.16 ± 0.53 -0.47 ± 0.50 -0.63 ± 0.55 vl 75 ± 42 81 ± 39 0.11 ± 0.19 -0.63 ± 0.34* -0.52 ± 0.41 vm 71 ± 50 77 ± 46 0.22 ± 0.18 -0.92 ± 0.40* -0.70 ± 0.44* anterior posterior anterior vs posterior control vs anterior control vs posterior bf 93 ± 36 93 ± 36 0.11 ± 0.15 -0.26 ± 0.30 -0.37 ± 0.26 gmax 71 ± 50 71 ± 50 -0.13 ± 0.17 -0.39 ± 0.46 -0.52 ± 0.40 rf 92 ± 63 75 ± 67 -0.21 ± 0.26 -0.21 ± 0.30 -0.42 ± 0.33 st 80 ± 25 80 ± 33 0.05 ± 0.28 -0.70 ± 0.48* -0.65 ± 0.57 vl 81 ± 39 81 ± 39 -0.05 ± 0.16 -0.48 ± 0.35 -0.53 ± 0.42 vm 77 ± 46 77 ± 46 -0.08 ± 0.27 -0.64 ± 0.39* -0.73 ± 0.46* proximal distal proximal vs distal control vs proximal control vs distal bf 87 ± 39 93 ± 36 0.10 ± 0.25 -0.47 ± 0.31 -0.38 ± 0.27 gmax 64 ± 44 71 ± 50 0.22 ± 0.36 -0.72 ± 0.41* -0.50 ± 0.39 rf 75 ± 67 75 ± 67 -0.07 ± 0.22 -0.37 ± 0.30 -0.45 ± 0.35 st 80 ± 33 80 ± 33 0.08 ± 0.39 -0.72 ± 0.59 -0.64 ± 0.56 vl 69 ± 45 81 ± 39 0.43 ± 0.29 -0.89 ± 0.47* -0.46 ± 0.36 vm 65 ± 55 77 ± 46 0.32 ± 0.27 -0.97 ± 0.46* -0.65 ± 0.41* * represents a substantial difference compared with the other condition. bf, bicep femoris; gmax, gluteus maximus; rf, rectus femoris; st, semitendinosus; vl, vastus lateralis; vm, vastus medialis. . original research 5 sajsm vol. 34 no.1 2022 the emg activity of the gmax, vl and vm was moderately lower for proximal loading compared to the control, while the emg activity of the vm was moderately lower for distal loading compared to the control (es:0.65-0.97). unilateral loading for unilaterally loaded conditions, no substantial differences in emg activity were observed between the loaded and unloaded leg (all es rated as unclear). discussion the aims of this preliminary study were to investigate the effects of different wr loads and loading placements during high-speed running efforts on stride characteristic variables and emg responses. the main findings were as follows: (1) bilateral wr loading induced no substantial changes in stride characteristics or force metrics for all loads and placements (2) proximal loading patterns moderately decreased gmax, vl and vm emg activity, while distal loading patterns induced moderate decreases in vm emg activity (3) anterior and posterior wr load placement induced decreases in st and vm emg activity. overall loading effects accelerometry data showed no substantial changes in stride characteristics (ct, stride frequency) and force metrics (peak force, kvert) of the loaded conditions compared with the control. this study does not support previous findings regarding the effects of wr on stride characteristics and force metrics.[1] previous research highlighted that wr induced increases in stride frequency can occur in parallel to decreases in stride length,[13] which may result in decreased lower limb muscle activity.[14] however, as the observed changes in stride frequency were unsubstantial, changes in muscle activity may have been as a result of participants changing their joint kinematics, which may change the amount of muscle under the electrode thus potentially changing emg amplitudes and recorded muscle activity.[1] regarding stride frequency, there were large differences in individual responses to the load and placements which are difficult to explain without emg and accelerometry synchronisation but would be worth investigating in future studies. previous studies have shown wr to increase the metabolic load of training.[15] this, in addition to its ability to decrease neuromuscular load, may highlight the ability of wr to be a useful tool for coaches to utilise for training purposes while minimising injury risks. however, further research is necessary to quantify the effects of calf-loaded wr on stride kinematics. effect of the load when examining the effect of the load compared to the control, there were no substantial effects of 0.75% or 1.5% bm wr loading on stride characteristics or force metrics. additionally, no differences were observed from the accelerometry data between the two loaded conditions. however, we found that emg activity of the quadricep muscles (vl and vm) were substantially lower for the 0.75% bm loaded condition compared to the control. furthermore, the vm muscle showed decreased emg activity for the 1.5% bm condition compared to the control. the vl and vm are the hip flexors responsible for force production and the stabilisation of the knee during running [16, 17] and they exhibit their highest workload during fig. 2. intra-subject stride frequency (steps/sec) values for each wearable resistance (wr) load and loading pattern with group statistics shown within box plots. each subject is represented by a line on each graph. a) anterior and posterior loading compared to control, b) proximal and distal loading compared to control, c) 0.75% and 1.5% bm loads compared to control. original research sajsm vol. 34 no.1 2022 6 the foot strike and early stance phases of running.[16] these findings suggests that 0.75% and 1.5% bm loading induced decreases in the neuromuscular workload for the quadricep muscles responsible for force production during running without effecting running mechanics. therefore, wr could potentially be a useful tool for rehabilitation protocols to reduce the neuromuscular load and potentially minimise injury risk. however, further research is required to investigate these findings using a larger testing cohort. the finding of no substantial differences in accelerometry data between the two loaded conditions supports previous findings whereby there were no meaningful changes in stride frequency between 3% and 5% bm lower body loading.[1] contrary to the previous study[1] in which the load was placed on the thighs and calves, the load in this study was focused solely on the calves. calf loading can induce a greater rotational inertia than thigh loaded wr due to its increased distance from the rotational centre (hip joint) [1] thus, increases in calf loading could potentially result in greater effects to stride frequency than thigh loading. however, this needs to be investigated using a larger scale study. this information may be useful for coaches wanting to utilize wr loading patterns that may maximize performance adaptations elicited by this training modality. interestingly, emg data showed no changes in muscle activity between the 0.75% and 1.5% bm loaded conditions. this was potentially due to minimal increases in motor unit recruitment from the small loads relative to bm. alternatively, in accordance with previous studies, the lack of emg changes may have been due to a reduced emg sensitivity to small differences in loads.[18-20] effect of load placement regarding load placement, we found that anterior, posterior, proximal and distal load placements did not have any clear effects on stride characteristics. previous research investigated the acute kinetic changes of shank vs thigh loading,[1] but to our knowledge this is the first study to investigate varying calf loading patterns. there were no meaningful differences found between posterior and anterior 3% bm thigh loaded wr during sprint accelerations for kinematic measurements.(1) however, we found that proximal loading caused decreases in gmax, vl and vm emg activity compared with the control and distal loading. anterior and posterior loading also caused decreases in vm emg activity, whereas no changes in stride frequency were observed between these conditions. the roles of the vl and vm muscles during running were previously stated and due to their importance for force production, proximally placed lower-limb wr loading may be a useful tool to reduce the neuromuscular workload of these muscles and reduce injury risks.(16, 17) moreover, due to their role as hip flexors involved in vertical movement patterns, such as raising the leg during running, the decreases in vl and vm emg activity may fig. 3. typical raw data for vertical acceleration and emg activity for four different conditions. emg activity is expressed for the right (r) and left (l) vastus lateralis (vl). the mean root mean square (rms) is indicated for each muscle and each trial presented. the four presented conditions are: control condition; 1.5% bm proximal, anterior loading; 1.5% bm distal, posterior loading; 0.75% bm distal, posterior loading. original research 7 sajsm vol. 34 no.1 2022 suggest an association with decreases in stride length.[17] however, further investigations are required to research these points in the context of wr training. as previously stated, decreases in gmax emg activity was induced by proximal loading. the major functions of the gluteus maximus muscles during running are to provide trunk stability during the stance phase, decelerate the swing leg and assist with leg extension.[21] the gmax is most active during high-speed running.[21] decreases in gmax emg activity may be useful for reducing neuromuscular load during high-speed running thus proving to be a useful tool for rehabilitation training by reducing potential injury risks. however, as stated previously, further research is required to investigate these findings. unilateral loading unilateral wr loading showed no substantial differences in emg activity between the loaded and unloaded leg. as previously discussed, it is possible that the lack of substantial differences observed between the loaded and unloaded leg may have been due to a reduced emg sensitivity to these small loads.[18] further research is required to assess the effects of wr unilateral loading on stride characteristics and emg activity using greater loads. while the study findings may not have been conclusive in identifying the stride characteristics and emg activity of using lower-limb wr, the results from previous lower-limb loaded wr studies imply that using wr may allow coaches to induce a training overload explicit to sportspecific movement mechanics.[5-7] furthermore, lower-limb wr may be used to increase acute training workloads, but further research is required with larger sample sizes to understand the locomotor and neuromuscular effects of wr training in more detail.[6, 7] future research may also aim to increase the wr load or increase exposure times to the load, to investigate potential performance benefits of wr training. from a chronic standpoint, it is not known what performance adaptations a prolonged period of wr training could potentially provide, thus further research will be required to investigate this. limitations the main limitation of this study was the lack of mechanical and emg data synchronisation which would allow the observation of emg differences when different stride phases are used. while using a within activity normalisation approach for a high-speed, highly dynamic activity seems preferable, another approach which could have been used would be to perform maximal voluntary contractions (mvc) of each lower-limb muscle before testing and using this to normalise emg signals across all conditions. this would have ensured accurate comparisons of intraand inter-muscle activity. furthermore, it was not possible to measure unilateral accelerometry data to identify this type of load placement effects on stride kinematics. finally, the sample size of this preliminary study is small and thus lacks the statistical power to draw general conclusions. however, its value allows for the implementation of larger wr training studies with greater statistical power. conclusion this preliminary study suggests wr induces locomotor and neuromuscular changes during high-speed running. these findings have provided the rationale for the design of further research studies using larger sample sizes to investigate which stride characteristics and neuromuscular performance adaptations can be provided by acute and chronic exposure to wr training. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: all listed authors contributed substantially to the concept, design analysis and interpretation of data and all authors approve the version to be published. references 1. feser eh, macadam p, cronin jb. the effects of lower limb wearable resistance on sprint running performance: a systematic review. eur j sport sci 2020; 20(3):394-406. 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[doi: 10.1242/jeb.02255] [pmid: 16709916] original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license do upper leg compression garments aid performance and reduce exercise-induced muscle damage in recreational marathon runners? km kabongo,1 msc; a emeran,2,3 bsc (med)(hon); an bosch,2,3 phd 1 division of physiotherapy, department of human biology, department of health and rehabilitation sciences, faculty of health sciences, university of cape town, cape town, south africa 2 uct research centre for health through physical activity lifestyle and sport (hpals), department of human biology, faculty of health sciences, university of cape town, cape town, south africa 3 international federation of sports medicine (fims) collaborative centre of sports medicine, university of cape town, cape town, south africa corresponding author: an bosch (andrew.bosch@uct.ac.za) marathon running has become increasingly popular and more competitive in recent years, due to its easy accessibility, its associated health benefits, and the popularity of iconic races.[1] an example of one such iconic and increasingly popular race is the boston marathon, with the number of marathon finishers increasing from 1 848 in 1972 to 26 657 in 2019.[2] despite the health benefits of long-distance running, many runners experience exercise-induced muscle soreness post training. most distance running racecourse profiles, such as the marathon, contain a variety of uphill, downhill, and flat sections. the downhill sections have the greatest effect on the lower extremity, as it induces a high proportion of eccentric muscle action on the quadricep muscles of the upper leg.[3] eccentric exercise, even in trained runners can result in exercise-induced muscle damage (eimd) resulting from mechanical damage to the sarcomeres. this mechanical damage leads to an inflammatory response, which is proposed to exacerbate the degree of damage.[4] the signs and symptoms of eimd include temporary reductions in muscle strength, decreased rate of force development (power), reduced range of motion, swelling, increased feelings of soreness and the appearance of intracellular proteins in the blood.[4] in recent years strategies to reduce symptoms of eimd and improve recovery processes have been investigated and implemented to improve performance of marathon athletes.[5] one such method is the use of compression garments (cgs) to improve performance and aid recovery in marathon runners.[6] there is limited knowledge on the mechanisms underpinning the efficacy of cg usage in marathon runners, although there are several hypotheses on possible mechanisms. these include a reduction in muscular microtrauma and tissue vibration during exercise, and reduced muscle fibre recruitment when utilising cgs.[7] it has also been proposed that cgs are effective in reducing the swelling and inflammatory processes associated with muscle damage. it is theorised that the cgs work by creating an external pressure gradient that reduces the space available for swelling to occur, thereby reducing the secondary inflammatory responses.[8] another theory is that the cgs improve venous return, reduce venous pooling, and promote the removal of metabolites, due to the muscle pump function.[9] the use of cgs by runners remains a controversial issue as there is a wide variety of findings in studies, often contrasting one another.[7] furthermore, as far as we are aware, most studies have investigated the use of compression socks and tights on performance and recovery, with few studies investigating the use of upper leg cgs specifically.[7] the aim of this study was therefore to assess the effect of upper leg cgs on performance and eimd in marathon runners using upper leg cgs in a marathon race, compared to runners who did not use cgs in the same race. subjective pain and midbackground: despite the lack of scientific knowledge on the physiological and biomechanical effects of wearing compression garments (cgs), there has been an increase in the use of compression garments (cg) amongst endurance runners. objectives: to compare marathon race performance, post-race pain, and mid-thigh circumference in marathon runners using upper leg cgs, with runners who did not use cgs in the same marathon race. methods: the study was conducted on healthy, long-distance runners (n=18) participating in the winelands marathon race, cape town, south africa. the cg group (n=10) participated in the race wearing upper leg cgs, while the control group (n=8) did not. participants were tested on three occasions for various subjective markers of exercise-induced muscle damage (visual analogue scale (vas) pain rating score, and likert scale for muscle pain), mid-thigh circumference for muscle swelling, and running performance (race pace). results: vas pain ratings for hamstring (p=0.04), knee flexion (p=0.02) and hip extension (p=0.04) were significantly lower than the ratings of the control group immediately post-race and two days post-race. no statistically significant differences were detected in race performance, mid-thigh circumferences or likert scale for determination of muscle soreness. discussion: wearing of upper leg cgs while running a marathon race improved vas pain ratings immediately post-race through to two days post-race. however, due to no placebo control, this beneficial effect may be psychological as opposed to a physiological effect of the cgs on muscle pain. conclusion: the use of upper leg cgs reduced subjective muscle pain in runners in the first 48 hours post-race. keywords: endurance running; recovery; muscle soreness; compression shorts s afr j sports med 2022;34:1-6. doi: 10.17159/2078-516x/2022/v34i1a14169 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a14169 https://orcid.org/0000-0002-9543-9408 https://orcid.org/0000-0003-2217-6608 https://orcid.org/0000-0002-7791-5298 original research sajsm vol. 34 no.1 2022 2 thigh circumference (an indirect measure for muscle swelling and inflammation)10 were used as indirect measures of muscle damage. methods study design and participants eighteen recreational marathon runners volunteered to participate in this randomised controlled intervention study. inclusion criteria required the participants to be free from lower limb musculoskeletal injuries for the previous three months prior to participation, pass a physical activity readiness questionnaire (par-q) and medical clearance. they were required to be 20-45 years old, be participating in the winelands marathon (42.2km), have a minimum average training distance of 50km per week and to have completed at least one marathon in the preceding 18 months. furthermore, any participants who had routinely used cgs and/or who were unwilling to train and/or compete with or without cgs based on the potential group allocation, were excluded. the participants were initially matched based on their sex, age, and personal best marathon time. they were then randomly allocated to either a cg group (n=10) wearing cgs or a control group (n=8). both groups were instructed to train as usual and record their training. the cg group participated in the race while wearing upper leg cgs. the control group were instructed to neither train nor participate in the race with cgs. ethical considerations the study was conducted on the principles of the declaration of helsinki (2013). ethical approval was approved by the university of cape town (uct) human research ethics committee (hrec) (hrec: 208/2019). written informed consent was obtained from all participants prior to their participation. data collection testing and data collection occurred on three separate occasions. the initial data collection (visit 1) was performed three days before the marathon. mid-thigh circumference was recorded. body mass was measured with a calibrated digital scale and stature was measured with a stadiometer to calculate the body mass index (bmi). body fat percentage was calculated after measuring the skinfold thickness of four sites: biceps, triceps, subscapularis and suprailiac crest, with a harpenden skinfold caliper.[11] these data are reported in table 1. the second data collection (visit 2) was performed directly after the completion of the winelands marathon. the midthigh circumference measurements were repeated at this visit and the participants completed a likert scale for determination of muscle soreness, as well as a visual analogue scale (vas) pain ratings questionnaire. the final data collection (visit 3) was performed two days following the marathon, with the mid-thigh circumference measurements, the likert scale, and vas pain rating questionnaires being repeated. the race performance results of the participants were retrieved electronically, and participants' finish times and average race pace were recorded. in addition, a questionnaire was completed to assess cg utilisation, nutrition and fluid strategies during the race, recovery modalities used, training details for a period of six weeks prior to the marathon, and menstrual cycle for females (to account for any possible confounding variables during the race). mid-thigh circumference the mid-thigh circumference was measured to estimate postrace exercise-induced muscle swelling.[11] one commonly used method for circumference measurements is using a tape measure, as it is inexpensive, efficient, rapid, and reliable.[12] the participants’ measurements were obtained without cgs and taken midway between the trochanterion and lateral border of the tibia, at the mid-trochanterion-tibiale laterale site (according to the international standards for anthropometric assessment).[13] each measurement was performed three times and the average value reported. visual analogue scale for pain ratings a vas questionnaire was administered to determine subjective pain ratings on a scale of 0 – 10 and was used in conjunction with non-weight bearing active movements of the hip and knee. zero represented no pain and 10 represented severe pain. the construct validity of the numerical version of the vas has been recorded as high as 0.91.[14] the participants were required to mark on the line the point that they felt represented their perception of pain. the vas score was determined by measuring in millimetres from the left-hand end of the line to the point that the participants marked. likert scale for determination of muscle soreness the likert scale for the determination of muscle soreness was administered for subjective pain rating based on a six-point system. zero represented a complete absence of muscle soreness and 6 represented severe pain that limited the ability to move. the participants ticked what best described their muscle soreness. race time finishtime timing chips are internationally recognised, highly reliable and validated and was the official timing tool used for the winelands marathon (finishtime.co.za).[15] the time to complete the race was obtained from the online results and used to calculate the overall average running pace (min:sec/km) during the race. compression garment composition commercially available, graded upper leg cgs produced internationally (china) were used in the study. the composition of the garments was 55% nylon, 40% polyester and 5% elastane fabric. the manufacturers of the cgs were not involved in financing the study. the pressure exerted by the cgs on the leg was not measured. original research 3 sajsm vol. 34 no.1 2022 statistical analysis all statistical analyses were performed using sas software version 9.4 (2020) and microsoft excel software (2019). the confidence intervals were set at 95% and statistical significance was determined as p<0.05. due to data not being normally distributed, a nonparametric approach for analysis was used. for race performance, midthigh circumference, vas pain rating, likert scale for the determination of muscle soreness, descriptive data (age, height, body mass, bmi, body fat percentage and previous best marathon time) and for the questionnaires, the mannwhitney u test was used to compare the groups. to determine differences in previous training history and recovery modalities, a fisher's exact test was performed. to determine whether there was a difference in the frequency of use of cgs prior to the study, the cg frequency scale was compared between the groups using a cochran-armitage test for trend. in addition, a hodges-lehmann 95% confidence interval for the median difference was calculated. results runners were recruited by an email sent to all winelands marathon 42.2km entrants aged between 20 and 45 years. forty responses were received with all 40 being eligible to participate. after the screening process, one participant was excluded. a further 19 participants withdrew from the study before the first data collection, with the majority withdrawing due to being too busy to attend the sessions, work commitments, transport issues, change of plans and deciding to race the half marathon (21.2km) instead. thereafter, there were 10 participants in each group. a further two participants withdrew during the data collection process at visit 2, and one participant in the control group injured his hamstring during the race and was unable to complete the race. a second participant in the cg withdrew due to logistical issues, as he did not report for follow-up visits. only participants who completed all three visits of the data collection process were included in the final reporting of the study. no statistically significant differences were observed in the baseline descriptive data of the two groups (table 1). race performance the race pace was utilised to measure the performance of the participants (from start to finish of the 42.2km marathon race). the cg group had an average race pace of 6:11 min:sec/km compared to 6:44 min:sec/km of the control group, which was not statistically significantly different (p=0.27). both groups had a slower running pace (min/km) compared to their personal best times (table 1). to adjust for the relative effort of each runner relative to their best marathon time, the difference in running pace (min/km) between the winelands marathon and personal best was calculated. however, no statistically significant differences were found between the groups (p=0.69). mid-thigh circumference the cg group’s median mid-thigh circumference increased slightly (0.20cm) from baseline testing (53.8cm) to immediately post-race (54.0cm) compared to the control group which recorded a 0.15cm decrease from baseline (52.4cm) to immediately post-race (52.3cm). two days post-race the cg group median mid-thigh circumference decreased from 54.0cm table 1. demographic, body composition and training descriptive data of the cg and control groups cg (n=10) control (n=8) p-value males (n) 6 6 females (n) 4 2 age (years) 38 (28-42) 38 (36-39) 1.00 body mass visit 1 (kg) 74 (64-89) 77 (69-80) 0.97 body mass visit 2 (kg) 72 (63-86) 74.70 (66-78) 0.97 body mass visit 3 (kg) 74 (62-89) 77 (68-80) 0.97 height (cm) 172 (167.75-177.50) 174 (167.88-177) 0.31 body fat (%) 24 (22-30) 23 (21-27) 0.66 bmi (kg/m2) 25.70 (23.70-26.40) 24.90 (22.90-26.70) 0.86 pace in pb marathon in past 18 months (min:sec/km) 05:44 (04:51-06:18) 05:49 (05:39-06:48) 0.63 data are expressed as median (interquartile range) unless stated otherwise.cg, compression garment group; bmi, body mass index; pb, personal best fig. 1. box and whiskers plot of mid-thigh circumference by visit for the cg (n=10) and control (n=8) groups. the box indicates the median and the interquartile range (quartile 1 to 3). the “x” represents the mean. the “whiskers” indicate the range of the data. original research sajsm vol. 34 no.1 2022 4 to 53.6cm and the control group increased from 52.4cm to 53.6cm. however, none of these changes were statistically significant (p=0.37). the absolute mid-thigh circumference measurement changes over time are presented in figure 1. vas pain ratings immediately at the completion of the race and two days post-race, the vas pain ratings were recorded for the hamstring and quadricep muscles at rest, during hip flexion and extension, and knee flexion and extension. both groups decreased in median vas pain rating scores from immediately post-race to two days post-race. there were statistically significant differences in vas pain scale rating scores during knee flexion (p=0.02), resting hamstring (p=0.04), and during hip extension (p=0.04) for both legs immediately post-race and two days postrace, with the cg group having lower vas pain ratings compared to the control group (table 2). likert scale for the determination of muscle soreness a likert scale for the determination of muscle soreness scores was recorded immediately post-race and two days post-race. although the muscle soreness score decreased in both groups from post-race to two days post-race, with a greater decrease in the cg group compared to the control group, these changes were not statistically significant (p=0.46). the absolute change in median likert scale for determination of muscle soreness is presented in figure 2. questionnaire there were no statistically significant differences (p>0.05) found in self-reported data for training history prior to the winelands marathon, cg utilisation, muscle recovery strategies utilised, nutritional and fluid intake during the race and menstrual cycle for females. table 2. vas pain ratings immediately post-race and two days post-race for the cg and control groups immediately post-race two days post-race cg control p-value cg control p-value right left right left right left right left right left right left quadriceps at rest 2.50 (2.004.00) 2.50 (2.004.00) 2.00 (1.003.00) 2.00 (1.003.00) 0.69 0.69 0.00 (0.001.00) 0.00 (0.001.00) 1.00 (0.002.00) 1.00 (0.002.00) 0.69 0.69 hamstring at rest 2.50 (0.004.00) 2.50 (0.004.00) 4.00 (2.504.50) 4.00 (2.504.50) 0.04* 0.04* 0.00 (0.001.00) 0.00 (0.001.00) 1.00 (0.003.00) 1.00 (0.003.00) 0.04* 0.04* during knee flexion 2.50 (1.005.00) 2.50 (1.005.00) 5.00 (3.507.00) 5.00 (3.507.00) 0.02* 0.02* 1.00 (0.002.00) 1.00 (0.002.00) 2.00 (2.003.50) 2.00 (2.003.50) 0.02* 0.02* during knee extension 2.50 (1.004.00) 2.50 (1.004.00) 3.50 (2.004.50) 3.50 (2.004.50) 0.21 0.21 0.50 (0.002.00) 0.50 (0.002.00) 1.50 (1.002.00) 1.50 (1.002.00) 0.21 0.21 during hip flexion 3.50 (2.004.00) 3.50 (2.004.00) 3.00 (2.004.50) 3.00 (2.004.50) 0.33 0.33 1.00 (0.002.00) 1.00 (0.002.00) 2.5 (1.004.00) 2.5 (1.004.00) 0.33 0.33 during hip extension 2.50 (2.004.00) 2.50 (2.004.00) 4.00 (2.005.50) 4.00 (2.005.50) 0.04* 0.04* 1.00 (0.002.00) 1.00 (0.002.00) 2.5 (2.003.50) 2.5 (2.003.50) 0.04* 0.04* data are expressed as median (interquartile range) unless stated otherwise. vas pain rating is on a scale of 0 to 10 where 0 is no pain and 10 is severe pain. right and left refers to the side or limb where the vas pain rating was recorded.* indicates p<0.05; cg, compression garment group. fig. 2. box and whiskers plot of likert scale score by visit for the cg (n=10) and control (n=8) groups. the box indicates the median and the interquartile range (quartile 1 to 3). the “x” represents the mean. the “whiskers” indicate the range of the data. the dots represent outlier values. the likert scale indicates subjective muscle soreness based on a six-point system where 0 represented a complete absence of muscle soreness and 6 represented severe pain that limited the ability to move. original research 5 sajsm vol. 34 no.1 2022 discussion this study compared the performance, pain and mid-thigh circumference changes in marathon runners using upper leg cgs against runners who did not use cgs in the same marathon. the main findings were that cgs resulted in vas pain ratings which were statistically significantly better postrace compared to the control group. however, there were no statistically significant improvements in race time, mid-thigh circumference measurements or likert scale score for muscle soreness post-race. race performance no difference in race performance was observed between groups (p=0.27), indicating that the cgs did not improve running performance. this finding concurs with other studies that observed no improvement in race running times and endurance performance when wearing lower limb cgs.[7,16,17] in contrast, some studies testing lower limb cgs in runners during incremental and step tests, found small positive effects on time to exhaustion.[7] mid-thigh circumference it has been proposed that cgs could reduce exercise-induced swelling and potential inflammation associated with eimd[8,9], which is theorised to cause an increase in overall mid-thigh circumference.[8] although the control group had an overall increase in midthigh circumference at two days post-race, while the cg group had a decrease at two days post-race, none of these changes were statistically significant. (p=0.37). similarly, a study by geldenhuys et al.[16] found no statistically significant changes in the calf circumference of runners wearing cgs post-ultramarathon race. however, a smaller increase in ankle circumference post-race to two days post-race in a cg group, compared to a control group (p=0.01) was reported.[16] this is similar to our study, where the midthigh circumference of the control group increased more than the cg group at two days post-race, albeit not statistically significant. thus, the results of this study do not support the theory of cgs reducing swelling and inflammation through changes in mid-thigh circumference. the use of biochemical markers of inflammation may be a more accurate, albeit a more invasive method of measuring inflammatory changes post-exercise. however, a study by pruscino et al. found no differences in inflammatory markers when a lower cg was worn after intermittent exercise, compared to a control group. [17] vas pain rating scale the main findings of the current study were found within the vas pain rating outcome measure, with several statistically significant findings in the cg group, including a lower resting hamstring vas pain rating score at rest, on hip extension and knee flexion immediately post-race and two days post-race, compared to the control group. thus, the cgs were associated with a reduction in subjective pain for a period of 48 hours post-completion of a marathon. these findings are similar to the results of previous studies,[4,7] in which muscle soreness was reduced in runners when utilising cgs, but contradict the findings of geldenhuys et al., who reported a higher vas pain rating score for participants wearing below-knee compression garments post-ultramarathon, compared to a control group.[16] based on the findings of the current study, it is suggested that the use of upper leg cgs during running may be beneficial as it may assist with recovery in the first 48 hours post-race. however, the practical importance of this may be limited, unless it extends to long distance training runs, as runners who have participated in a marathon race will move into a recovery phase of training, and thus it is of limited importance whether the wearing of cgs during a race reduces post-race eimd and improves recovery. speeding up recovery from long training runs, however, could be very useful in an athlete attempting to maximise training load. likert scale in addition to the vas pain rating, an additional subjective pain scale (the likert scale) was used to assess pain scores. the likert scale assessed functional activities compared to the vas pain rating which assessed static and dynamic movements of the hamstring and quadricep muscle. to our knowledge this is the first study to utilise this subjective assessment of muscle soreness in the study of cgs. it would be anticipated that the cg group would report lower scores, as suggested by the vas pain ratings. however, there were no statistically significant findings detected between the groups in muscle soreness based on the likert scale. study limitations there are several limitations of the current study, including a small sample size, using subjective measures of muscle damage (pain scales) and indirect measures of muscle swelling (midthigh circumference), that may not be as accurate as objective measures. although the pressure exerted by the cgs on individual participants was not measured and may be seen as a limitation, several studies have found no apparent association between pressure applied and cg effects, as beneficial effects have been observed in both high and low pressure cgs.[19] a post-race performance test was not performed, which could have been a direct measure of recovery. furthermore, the study did not control for a possible placebo effect. thus, results should be taken with caution, with the possibility that the greater reduction in vas pain ratings in the cg compared to the control group could be a psychological benefit as opposed to physiological.[17] conclusion in conclusion, the wearing of upper leg cgs while running a marathon race did not improve race performance, change postrace mid-thigh circumference, or improve likert scores for muscle pain. however, reduced vas pain ratings were reported post-race for the hamstring at rest, knee flexion and hip extension movements, compared to a control group. based on the findings, there is indication from some of the measures original research sajsm vol. 34 no.1 2022 6 used that the use of upper leg cgs reduces subjective muscle pain in runners in the first 48 hours post-race, which may aid in recovery. the lack of a performance benefit, and the small improvement in self-reported pain post-race suggests that it is probably of limited value to use upper leg cgs during a race. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors would like to thank the participants for being involved in the study. author contributions: kk: conducted the study and prepared initial manuscript. ae: assisted with preparation of the manuscript for publication. ab: conceived and designed the study and edited manuscript. all authors approved final version to be published. references 1. van gent rn, siem d, van middelkoop m, van os ag, biermazeinstra sm, koes bw. incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. br j sports med 2007;41(8):469-480. 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[ doi: 10.1002/acr.20543] [pmid: 22588748] 15. finishtime. results. finishtime, 2019. https://results.finishtime.co.za/stats.aspx?cid=35&rid=2930. (accessed 10 november 2019). 16. geldenhuys ag, swart j, bosch a. investigation of the impact of below-knee compression garments on markers of exerciseinduced muscle damage and performance in endurance runners: a prospective randomized controlled trial. sports health 2019;11(3):254-264. [doi: 10.1177/1941738119837644] [pmid: 31034342] 17. pruscino cl, halson s, hargreaves m. effects of compression garments on recovery following intermittent exercise. eur j appl physiol 2013;113(6):1585-1596. [doi: 10.1007/s00421-012-2576-5] [pmid: 23314683] 18. dascombe bj, hoare tk, sear ja, reaburn pr, scanlan at. the effects of wearing undersized lower-body compression garments on endurance running performance. int j sports physiol perform 2011;6(2):160-173. [doi: 10.1123/ijspp.6.2.160] [pmid: 21725102] 19. beliard s, chauveau m, moscatiello t, cros f, ecarnot f, becker f. compression garments and exercise: no influence of pressure applied. j sports sci med 2015;14(1):75-83. [pmid: 25729293] https://www.baa.org/races/boston-marathon/results/participation https://www.baa.org/races/boston-marathon/results/participation https://results.finishtime.co.za/stats.aspx?cid=35&rid=2930 original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license the pattern of non-contact injuries in a south african professional football team j swart,1 mbchb, phd, c varekamp,1 mphil (sports physiotherapy), j greyling,2 msc (physiotherapy) 1 hpals research centre, faculty of health sciences, university of cape town, south africa 2 point physiotherapy, cape town, south africa corresponding author: j swart (jeroen.swart@uct.ac.za) football has grown into a faster, more intense and more competitive game, with a substantial increase in technical and physical demands resulting in a higher risk of injuries. [1] this risk is significantly higher during match play compared to training. [2] norwegian football players sustained 1.4 non-contact injuries per 1 000 exposures and this risk was not significantly higher during pre-season compared to the rest of the competitive season. [3] european football players sustain on average 0.6 muscle-related injuries per season, which results in 15 muscle-related injuries per team per season. [4] a recent meta-analysis of football-related injuries in professional players showed an overall incidence of 8.1 injuries per 1 000 exposure hours, a training incidence of 3.7 injuries per 1 000 exposures and a match incidence of 36 injuries per 1 000 hours of match exposure. non-contact injury rates were 2.1 per 1 000 exposures. [5] current data recorded for south african football are scarce, with one study recording an overall injury rate of 2.2 per 1 000 exposures [6]) while another recorded 13.4 injuries per 1 000 exposures. [7] further research into injury rates in south african football is therefore warranted. of all injuries sustained, non-contact injuries account for 935%. [3] the lower extremity is the most commonly affected site in professional football players. [6] this is due to the continual load placed on the legs during training and competition. the hamstrings are the most commonly affected muscles, accounting for 37% of injuries, followed by adductors (23%), quadriceps (19%) and calf muscles (13%).[4] to reach the peak demands of match play, extensive training is necessary to improve performance and to reach the top level in professional football. inadequate training loads prevent optimal performance adaptions, placing the player at higher risk of being underprepared and may increase the risk of noncontact injuries.[8] inadequate training load (tl), repetitive movements, deficient technical execution performed for long periods in combination with inadequate and insufficient recovery or rehabilitation are possible causes of non-contact injuries. [9,10] in addition, playing position has a large influence on physiological demands and this may influence the risk of sustaining an injury. [1,11] different positional roles require unique physiological, technical and tactical performances from the individual player.[1] leventer[11] determined that midfielders sustain the most injuries (38%) and have the highest incidence of match injuries, followed by defenders (30%) and attackers (21%). however this finding has not been confirmed by other researchers [12], while the injury risk relative to the number of players in each playing position or the injury risk relative to the number of exposures in each position of play has background: the incidence, pattern and severity of non-contact injuries in european football has been researched extensively. in south african football only two studies have been conducted to date and with disparate outcomes. further research into injury rates in south african football is therefore warranted. objectives: to determine the incidence and pattern of non-contact injuries in a south african professional football team during the course of a single season (2016-2017) in relation to competition exposure, training load and playing position. methods: thirty-four male professional football players belonging to a single team competing in the premier soccer league (psl) in south africa were studied. non-contact time-loss injuries (total training and match injuries) were recorded. injury incidence, location, severity, type, and playing position (defender, midfielder, attackers, goalkeepers) during either match play or training were recorded. results: the non-contact incidence was 52 injuries with an injury rate of 3.74 per 1 000 exposures (training and competition). competitions resulted in an incidence of 26.4 injuries per 1 000 exposure and training incidence 2.08 injuries per 1 000 exposures. hamstring, groin and quadriceps injuries were the most frequently injured locations and muscle-tendon injuries accounted for the majority of injuries. the majority of injuries (52%) occurred during match play while 48% occurred during training. the greatest absolute number of injuries were sustained by midfielders (50%), followed by defenders (33%) and attackers (17%). however, relative to player numbers, the greatest number of injuries during match play were for defenders (44%), attackers (32%) and midfielders (24%). during training attackers sustained the most injuries (39%), followed by defenders (31%) and midfielders (30%). goalkeepers did not sustain any non-contact injuries during the duration of the study. conclusion: the non-contact injury incidence in south african professional football players is similar to european football players. hamstrings and groin injuries are predominant and were sustained throughout the competitive season. defenders sustained the most non-contact injuries within the team relative to exposure time compared to attackers and midfielders. to our knowledge, injuries relative to player position have not been reported previously. keywords: football injuries, training load, epidemiology s afr j sports med 2022;34:1-5. doi: 10.17159/2078-516x/2022/v34i1a13723 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13723 https://orcid.org/0000-0001-7098-0313 original research sajsm vol. 34 no.1 2022 2 not been examined directly. we documented the incidence of non-contact injuries in a professional football team during a competitive football season. in addition, injury rate per player position and position specific exposure were documented. methods participants thirty-four male professional football players belonging to the first team of a professional football team ((mean ± sd): age 24.3 ± 4.1 years; height 173.4 ± 6.0 cm; body mass 74.3 ± 6.7 kg) were recruited during the 2016/2017 competitive south african premier soccer league (psl) season. the players were recruited through direct communications with the club. all participants provided written informed consent and the research study was approved by the university of cape town human research ethics committee. procedures participants were enrolled in the study for 11 months. exposure data were recorded for each player for all training sessions and matches by the conditioning staff. all injuries were assessed and recorded by the medical staff of the team. these data included the date and time of the injury, mechanism of injury, location, type of injury, severity, recurrence of injury and duration before return to play (rtp). data analysis the analysis included all non-contact injuries sustained during all on-field training sessions and matches throughout the 2016/2017 competitive season. a non-contact injury was defined as an injury occurring suddenly or insidiously and progressively over time and presumably caused by repetitive motion or micro trauma and/or accumulative movements without an identifiable responsible event such as a collision. [9,13] non-contact injuries differ from acute contact injuries caused by an acute moment or identifiable trauma. injuries were defined as either training or match related and were recorded as time-loss injuries if the player was not able to return to play within 24 hours.[14] medical attention injuries whereby the player was able to participate in full training the next day (within 24 hours) were not included in this research. a recurrent injury was defined as an injury affecting the same structure, at the same site and of the same type as the previous injury, which occurred after return to play [14], during the course of the 2016/ 2017 competitive season. injuries unrelated to football, contact injuries and illness were not included in this research. the study therefore only included time-loss non-contact injuries. injuries were categorised according to the site of injury and included; hip, groin, adductors, quadriceps, hamstrings, knee, calf, and ankle, and foot. injury rates were assessed as the number of non-contact injuries occurring relative to each 1 000 training and match play hours (exposures). groin injuries were classified according to the doha consensus agreement [15], and included adductor, iliopsoas, inguinal, hip, and pubic-related groin pain. injuries were ranked as minimal, mild, moderate, and severe based on days out of training and competition. a minimal injury was defined as >24 hours – 3 days of football activity missed, mild (4–7 days), moderate (1–4 weeks) or severe (4+ weeks). [14] the risks of these injuries are calculated as the number of injuries sustained relative to the exposure of each workload classification. injury exposure and incidence injury incidence was calculated by dividing the total number of non-contact injuries by the overall injury exposure, and expressed as rates per 1 000 hours. [13] match injury exposure was calculated by multiplying the number of players by the session duration of match play and the number of matches played. [13] total number of non-contact injuries sustained during match play were divided by the exposure hours and described as injuries per 1 000 match playing hours (13). on-field training non-contact injury exposure was calculated by multiplying the number of players by the average duration of the on-field training sessions and the number of on-field training sessions during the full competitive season. [13] the team also performed, on average, two strength training sessions per week of 60 minutes duration each and these were included in the training exposure rates. the total number of injuries sustained during training sessions was therefore divided by the total exposure hours of on-field training and strength training and described as injuries per 1 000 training hours. [13] injury statistics were grouped by player's predominant position in the team. relative injury exposure was also calculated per number of players per playing position and per hours of training and match play. results injury incidence fifty-two non-contact injuries were sustained throughout the season, resulting in 3.74 non-contact injuries per 1 000 hours of exposure. twenty-seven non-contact injuries (52%) were sustained during match play, resulting in 24.8 injuries per 1 000 hours of match play. twenty-five non-contact injuries (48%) were sustained during training, resulting in 1.96 injuries per 1 000 hours of training (figure 1). descriptive statistics for all overuse injuries are summarized in table 1. injury site muscles were the most frequently injured structures (85%). hamstring strains accounted for 48% of the total non-contact injuries sustained. groin injuries including adductor, inguinal and pubic-related groin pain accounted for 23% of all injuries sustained. quadriceps injuries were the third most common site of injury (12%). others, defined as injuries affecting hip flexors and gluteal muscles accounted for 6% of all injuries. time-loss injury affecting the hip joint, specifically a hip labral injury only occurred once (2%). lower leg injuries, including gastrocnemius and peroneus longus injuries, occurred three original research 3 sajsm vol. 34 no.1 2022 times (6%). non-contact overuse injuries affecting both the ankle and the knee (4%) only occurred once. the majority of hamstring (56%), quadriceps (66%) injuries occurred in the first 3 months of the season and overall 46% of the injuries occurred during this period. in contrast, groin injuries were mostly sustained in the mid-season and late season. lower leg injuries occurred in the pre-season and the end of the season. position injury risk midfielders were most likely to sustain an injury (50%), followed by defenders (32.7%) and attackers (17%). however, when expressed as injuries per 1 000 exposure hours, defenders sustained 23.7 injuries per 1 000 hours of match play (44% of all injuries). attackers sustained 17.2 injuries per 1 000 hours of match play (32%). midfielders sustained 10.7 injuries per 1 000 hours of match play (24%). during training, attackers were most likely to be injured and sustained 2.12 injuries per 1 000 hours (39% of all injuries). defenders sustained 1.7 injuries per 1 000 hours (31%) and midfielders only sustained 1.6 injuries per 1 000 hours (30%). goalkeepers did not sustain any noncontact injuries. midfielders experienced the highest risk of absolute injuries affecting the hamstring, quadriceps, hip flexors and knee. defenders sustained mostly hamstring and groin injuries. attackers were least often injured, but if injured, usually suffered hamstring, groin and lower leg injuries (figure 2). discussion the objective of this study was to describe the pattern of noncontact injuries in south african professional football players. a total of 52 overuse injuries were analysed in this study. a previous study of professional south african football players by calligeris, burgess, and lambert[7] reported 130 injuries from all causes over a full competitive season. in contrast to our study, calligeris et al [7] reported all injuries sustained, including contact injuries and injuries affecting the upper extremity. the study reported an overall injury rate of 13.4 injuries per 1 000 playing hours. in contrast, when only assessing non-contact injuries, we found an injury rate of 3.74 per 1 000 hours, which is similar to the reported incidence of 2.70-8.70 injuries per 1 000 playing hours on average in studies of european football players. [4] in addition, we found a significant difference between non-contact injuries between matches and training with 24.8 non-contact injuries per 1 000 match hours and 1.96 overuse injuries per 1 000 hours of training. fuller [16] investigated all cause injury incidence of english premier league football clubs and reported a match injury incidence of 26.9 per 1 000 hours and a training injury incidence of 4.3 per 1 000 hours. this incidence is only marginally greater than our data, partly due to the fact that fuller included all injuries. twenty-five of our reported injuries were sustained during training and 27 overuse injuries were sustained during match play. this similar to the findings in the study by lu et al. [17], who reported that 60%[4] of all non-contact injuries were sustained during match play. out of the 27 non-contact injuries table 1. total overuse injuries 2016/17 full competitive season (n=52) injury classification number % activity performed training 25 48 match 27 52 affected body part hamstring 25 48 groin 12 23 adductor related groin pain 6 12 pubic related groin pain 4 8 inguinal related groin pain 2 4 quadriceps 6 12 others (hip flexor and glut.) 3 6 hip 1 2 lower leg 3 6 ankle 1 2 knee 1 2 severity minimal 5 10 mild 13 25 moderate 30 58 severe 4 8 position played defenders 17 33 midfielders 26 50 attackers 9 17 goalkeepers 0 0 data rounded off to the nearest whole number. fig. 1. injuries sustained during training or match per month original research sajsm vol. 34 no.1 2022 4 sustained during match play in our study, 17 of these injuries affected the hamstring and six affected the groin. several other studies [4,8,11,14] have also concluded that hamstrings and groins are most often injured during match play. we reported that hamstring and quadriceps injuries were mostly sustained in the first three months of the competitive season. although only one official league match was played, five friendly matches were played during this time. this supports the hypothesis of gabbett & domrow[18], that the training load in the pre-season period is the greatest and training injuries in pre-season are therefore unavoidable. the study by impellizzeri[19]) also concluded that friendly matches were more regularly played in pre-season compared to inseason, which resulted in different periodisation and overall training load during the full season. this is also in line with the study by murray[20] that reported relatively more injuries in the pre-season compared to in-season. it may be assumed that an appropriate fitness level is reached in the second half of the season, therefore resulting in a lower number of overuse injuries. perhaps for the first time, we have described injury risk for player position according to the number of exposures for that position. this demonstrates that although the injury rate for midfielders is generally reported as being greatest, this may be due to the higher number of players in a squad who play in the midfield. when expressed relative to exposures, defenders are most likely to be injured during matches and attacking players are most likely to be injured during training. more research is required to confirm these findings and to elaborate on other factors which may contribute to this pattern. conclusion non-contact injuries in south african football occur at a similar incidence to european counterparts. most overuse injuries occur during matches and within the first three months of the season. hamstring and groin injuries are the most common injuries sustained. although midfielders sustain the most injuries, when expressed relative to exposure hours, defenders sustain the greatest number of injuries. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: js: study design, data collection, data analysis, manuscript preparation. cv: data analysis, manuscript preparation. jg: data collection. references 1. abbott w, brickley g, smeeton nj. positional differences in gps outputs and perceived exertion during soccer training games and competition. j strength cond res / national strength & conditioning association 2018;32(11):3222-3231. 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[doi: 10.1111/sms.12719] [pmid: 27418064] sajsm cpd.indd sajsm cpd instructions 1. read the journal. all the answers will be found there. 2. go to www.mpconsulting.co.za to asnwer questions. accreditation number: mdb001/015/01/2014 (clinical) true or false e�ective in 2014, the cpd programme for sajsm is administered by medical practice consulting: cpd questionnaires must be completed online at www.mpconsulting.co.za a maximum of 3 ceus will be awarded per correctly completed test. october 2014 radiological changes among artistic gymnasts 1. lower back (spinal) injuries account for ~80% of injuries in women’s gymnastics. 2. back injuries in gymnasts usually have a sudden onset. 3. degenerative disc disease and spinal injuries are more frequent in competitive female gymnasts than in asymptomatic non-athletic people of the same age. �e e�ect of semi-rigid ankle bracing on injured v. non-injured adolescent female hockey players 4. ankle bracing reduces the functional proprioceptive ability of the ankle joint due to limited movement in the frontal and transverse planes. 5. prolonged prophylactic ankle bracing decreases the neural �ring of the proprioceptors, which delays the activation of the ankle evertors, resulting in recurring ankle inversion sprains. 6. prophylactic semi-rigid ankle bracing is an e�ective rehabilitative management device for ankle injuries. pedometer-measured v. self-reported physical activity and current physical guidelines 7. self-reported measures of physical activity are accurate and are therefore typically considered to be objective measures. 8. pedometers traditionally present intensity-based information about physical activity, with little or no reference to volume. 9. nearly 40% of participants who met guidelines for physical activity did not reach the 10 000 steps/day target. doping in sport: attitudes, beliefs and knowledge of gauteng high school athletes 10 . over 50% of the athletes said that they would consider using a prohibited performance-enhancing drug if they knew they would not get caught. 11. e�ective testing continues to be an important component of antidoping initiatives. 12. �e risk of doping appears to be highest in speed and power sports. dietary supplements containing prohibited substances 13. prohormones are listed as permitted substances on the world anti-doping agency (wada) list. 14. male users of steroids concurrently use tamoxifen or other agents to prevent or treat gynaecomastia. 15. prostanozol, methasterone and andostatrienedione are examples of designer steroids. abrasion injuries on arti�cial turf 16. �ere is a decreased number of abrasion injuries on arti�cial turf compared with natural grass. 17. the mechanism of laceration injuries is similar to abrasion injuries. 18. sliding on natural grass resulted in more erythema but fewer abrasions compared with sliding on arti�cial turf. a case of cyclist’s nodule in a female patient 19. a cyclist’s nodule is a frequently diagnosed condition of the perineum a�ecting mostly female cyclists. 20. the differential diagnosis of cyclist’s nodule includes abscess, epidermal cyst, lipoma, and benign and malignant tumours. editorial 63 sajsm vol. 28 no. 3 2016 post-truth era and impact on the science associated with sport and exercise medicine we have entered an era in public life where truth has lost its status. truth is no longer the pinnacle that we strive for to settle debates, make decisions and drive policy. facts are conveniently twisted, shaped, and even created. this is most evident when we see politicians disregarding the truth in the determination of important decisions. they also draw upon their followers’ emotions to deceive them to push their political agendas. any challenge to the factual basis of their argument is met with an aggressive response, which often includes the words such as “fake news”a deliberate spread of misinformation. this is well characterised in all sectors of society, not only in politics, and is known as the “post-truth” era. the term ’post-truth‘was the oxford dictionaries word of the year in 2016. [1] the awards for word of the year are reserved for words that have attracted a great deal of interest in that particular year. ’posttruth’ is an adjective defined as ‘relating to or denoting circumstances in which objective facts are less influential in shaping public opinion than appeals to emotion and personal belief’.[1] it is concerning that the new term, ’post-truth’ that describes this negative trend in society was recognised with this international award. compare this to the word of the year for 2015 (emoji, a pictograph, also known as the face with tears of joy) or 2013 (selfie, a picture taken of oneself typically with a smartphone or webcam) – both innocuous in comparison to ’post-truth’. scholars have tried to explain the factors that have caused this phenomenon of post-truth. the easy access to social media, blogs and internet stories are largely to blame. we have seen this strategy used in the presidential campaigns in america. there are also examples of post-truth propaganda in south africa where groups with a political agenda are sponsored to tweet untrue stories in support of this agenda.[ 2] are scientists protected from this trend? it seems so because there are many checks and balances built into the propagation of knowledge through the scientific process. studies have to go through an institutional review board for ethical clearance, and research findings have to be reviewed before they get published. once papers are published they are open to scrutiny by the scientific community. these points alone convey some checks and balances to the distribution of facts that are not entirely true. however, despite this system that is designed to self-correct, scientists should not sit back and assume that the post-truth era is not going to influence the well-established scientific process. a problem threatening this process is the emergence of predatory journals. [3] the business model of predatory journal use contributes to the short circuiting of the established scientific process. predatory journals make authors pay for having their papers published. the submitted papers may undergo peer review, but the process is accelerated and the acceptance rate is high compared to that of the more legitimate journals, which reject about 80-90% of the submitted papers. predatory journals can be easily identified because they usually canvas for papers in an aggressive manner. the predatory journal often has a title that is similar to an established journal. they have editorial boards (some members have fake names) to provide some authenticity. sometimes academics are listed on the editorial board without ever having been formally invited or notified. the business model works for some, particularly the scientists who are under pressure from their academic institutions to publish. they are prepared to pay this price. others publish their material in these journals not realising that the journal is dubious. the increase of predatory journals is not a passing trend. their publication volumes increased from 53000 in 2010 to an estimated 420000 articles in 2014. [4] there are about 8 000 active predatory journals at present, with many of these in the health, exercise and sports medicine disciplines. [4] scientists need to guard against the abuse of the scientific process which occurs when they publish in predatory journals. there also needs to be a concerted effort to educate nonscientists on how to understand scientific claims. this has been attempted by the authors of a paper which lists 20 points which non-scientists should understand.[5] examples of these points in the paper include: differences and chance cause variation, bias is rife, controls are important, correlation does not imply causation, extrapolating beyond the data is risky and data can be dredged or cherry-picked. a better understanding of these and the other points mentioned in the paper, will make a contribution to the preservation of the scientific process. consumers of scientific papers, whether they be scientists, journalists, politicians, or members of the public will be better equipped to interpret the quality of the information if they have these basic skills. another way of protecting the scientific process is to disregard papers that represent poorly designed experiments. this includes studies with a low sample size, inadequate control and poor ecological validity. sometimes good journals let low quality studies slip through the review process – these poor quality papers should not be cited in other research, unless they are being used as an example of poor research. papers from predatory journals should be treated with caution and not cited unless the paper has been scrutinised for quality. without these filters we will rapidly head towards a post-truth era, with fake data polluting real data. the outcome of this scenario is gloomy. mike lambert editor-in-chief s afr j sports med 2016;28(3):63. doi: 10.17159/2078-516x/2016/v28i3a1838 references 1. word of the year 2016 is... https://en.oxforddictionaries.com/word-of-theyear/word-of-the-year-2016 (accessed 26th february, 2017) 2. justice malala: the truth behind the 'white monopoly capital' propaganda assault. https://www.businesslive.co.za/rdm/politics/2017-0123-justice-malala-the-truth-behind-the-white-monopoly-capital-propagandaassault (accessed 26th february, 2017) 3. beall j. predatory publishers are corrupting open access. nature 2012; 489(7415):179. [http://dx.doi.org/10.1038/489179a] 4. shen c, björk b-c. ‘predatory’ open access: a longitudinal study of article volumes and market characteristics. bmc med 2015; 13:230 [.doi.org/10.1186/s12916-015-0469-2] 5. sutherland wj, spiegelhalter d, burgman ma. policy: twenty tips for interpreting scientific claims. nature 2013; 503(7476), 335–337. [doi.org/10.1038/503335a] http://dx.doi.org/10.17159/2078-516x/2016/v28i3a1838 https://en.oxforddictionaries.com/word-of-the-year/word-of-the-year-2016 https://en.oxforddictionaries.com/word-of-the-year/word-of-the-year-2016 review 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license the profile of orthopaedic sports medicine publishing in south africa br gelbart,1 fc ortho, mmed; e schapkaitz,2 fc path, mmed; d levitt,3 1 department of orthopaedic surgery and wits sport and research group (wish), faculty of health sciences, university of witwatersrand medical school, johannesburg, south africa 2 department of molecular medicine and haematology, faculty of health sciences, university of witwatersrand medical school, johannesburg, south africa 3 pre-med yeshiva college, yeshiva university, new york, usa corresponding author: br gelbart (brad@linksfieldkneeclinic.co.za) recently, orthopaedic sports medicine has been recognised as a sub-speciality of orthopaedic surgery. for example, in the united states of america, many professional sports teams include orthopaedic surgeons among the team’s complement of treating physicians. in other countries, and to some extent in south africa, the medical care of professional sports teams is primarily managed by general practitioners (gps), who also have qualifications in sports medicine. this further sub-specialisation is necessary in order to best manage the sports person’s health and performance, in addition to injuries of the skeletal system. specialist orthopaedic care consultations are often required in particular for cases outside of the qualifications and capabilities of the team doctors. orthopaedic surgeons may specialise in a particular joint or area of orthopaedics, including trauma. it is therefore essential to recruit orthopaedic specialists who understand the pressure and demands placed on the professional sportsperson. furthermore, there are many patients who present to gps or specialists who are amateur or recreational sportspeople. for these individuals, returning to sports after injury is also important. it takes clinical skill, knowledge and experience to customise the treatment to the needs of the level of the athlete. south africa’s climate and infrastructure allows for a wide range of sports participation. exercise has been pioneered as a complementary approach to modifying lives and lifestyles. [1, 2] however, the increase in unfit and underprepared people who may be chasing the benefits of sports participation places a significant demand on gps and specialists. the south african journal of sports medicine (sajsm) and the south african orthopaedic journal (saoj) are open access, peer-reviewed journals that have provided ongoing education to the sports medicine community. sajsm was launched in 1982 with a significant representation of orthopaedic surgeons on the editorial board. the journal’s scope has evolved to include sports medicine, biokinetics, physiotherapy, exercise and sports science, dietetics, and psychology, with particular relevance to south africa. [3] in 2002, saoj was founded as the official publication of the south african orthopaedic association. it focuses specifically on orthopaedic surgery in south africa, with sub-disciplines of relevance to orthopaedic surgeons. these include paediatrics, hip, knee, tumour and sepsis, spine, shoulder and elbow, foot and ankle and hand surgery. [4] there are a number of benefits to having an open access journal, with a specific emphasis on these aspects, and related to south africa. in particular, the healthcare availability and resources for sportspeople differ according to country and region. a narrative review was conducted to appraise the content of these two south african journals, with a particular focus on sports orthopaedics. the primary aim of the study was to assess the articles in each journal according to each anatomical region, as well as a relationship to sports. the secondary aims were to assess the trends regarding the focus of the articles, the levels of evidence, and the origins of the research. methods a search of the sajsm and saoj was conducted electronically to identify online relevant articles using the table of contents. the sajsm was accessed through the ‘archives’ tab from 1982 to 2021. the year 2002, however, was missing online, and therefore no data could be collected for that year. the saoj was background: the south african journal of sports medicine (sajsm) and the south african orthopaedic journal (saoj) are two open access, peer-reviewed journals which provide ongoing education to the sports medicine community. objectives: the purpose of this review was to appraise articles with a sports orthopaedic focus published in sajsm and saoj. a secondary aim was to evaluate trends regarding the focus of the articles, levels of evidence, authors’ affiliations, and country of origin. methods: an electronic search of the sajsm from 1982 to 2021 and saoj from 2008 to 2021 was conducted to identify relevant articles. the eligibility of the articles was determined according to the following inclusion criteria: sajsm articles with reference to musculoskeletal anatomy and/or an injury in any sport, and saoj articles focusing specifically on sports, sports teams and low-velocity traumatic injuries in sports people. results: this study included specific sports orthopaedic articles in sajsm (n=161) and saoj (n=41). the articles originated from 67 institutions in 19 countries. in sajsm, the majority of articles were published by local authors (n=44, 61%). there was a non-significant difference in the proportion of articles from local and international institutions in saoj. in sajsm, the sports covered most frequently included rugby, cricket, running and soccer, whereas in saoj most articles referred to low-velocity injuries. with regard to trend analysis, a significant decline in articles with level v evidence published by sajsm was observed (p<0.001). similarly, articles with level v evidence published by saoj showed a decline, although it was non-significant. conclusion: the focus of sajsm in particular is relevant to sports played, injury patterns and the healthcare resources for sports people in south africa. the level of evidence published by sajsm has improved significantly over time. keywords: sports injury, knee injury, shoulder injury, rugby, soccer, levels of evidence, sports research s afr j sports med 2022;34:1-5. doi: 10.17159/2078-516x/2022/v34i1a14413 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a14413 https://orcid.org/0000-0001-7897-4508 https://orcid.org/0000-0003-2024-0442 https://orcid.org/0000-0002-1534-2930 review sajsm vol. 34 no.1 2022 2 accessed through the archives tab from 2008 to 2021 (issue 3). inclusion criteria in sajsm, articles with reference to musculoskeletal anatomy and/or an injury in any sport were included. in saoj, articles focused specifically on sports, sports teams and low-velocity traumatic injuries. exclusion criteria congress abstracts, errata, editorials and opinions were excluded. trauma-related articles specifically mentioning gunshot wounds, high-velocity trauma or post-traumatic sepsis were also excluded. study selection the index of each journal was scanned and the total number of articles published were identified. articles were initially screened against the review’s inclusion and exclusion criteria by title to assess the eligibility. an abstract and article review was also performed when eligibility was unclear by means of the title alone. the eligibility assessment was performed independently by two reviewers. articles were classified as ‘definite sports orthopaedic’ if the sport was mentioned and ‘possible sports orthopaedic’ if the sport was not mentioned but the article was possibly relevant to sports orthopaedics. ‘definite sports orthopaedic’ articles were included. the level of evidence was captured if available. the level of evidence for sajsm was not indicated in the articles. however, the level of evidence for saoj was indicated in the articles from the years 2018 until the year 2021. the articles were reviewed and assigned a level of evidence based on the oxford centre for evidence based medicine (oecbm) levels of evidence. [5] additionally, information pertaining to each article, including the specific anatomical region, sport, university or institute affiliations, and country of origin of the authors, were recorded. statistical analysis a custom excel spreadsheet was developed to collect the data. statistical analysis was performed using statistica 13.2 software (palo alto, california, usa). categorical data was presented as frequencies and percentages. comparisons were performed using a chi-square test or two-tailed fisher’s exact test where necessary. subgroup analysis, with multiple pairwise comparisons, was subsequently performed applying the bonferroni correction with a p-value <0.017 considered statistically significant. agreement between each reviewer was assessed using cohen’s kappa (κ) coefficient. results a search of 95 editions of sajsm and 55 editions of saoj was conducted and the results are shown in figure 1. a total of 1549 articles were identified. three sajsm volumes which published 127 congress abstracts were excluded. of the 1422 articles screened, there were 754 from sajsm and 668 from saoj. in sajsm, of the 162 (22%) eligible sports orthopaedic articles, 161 (21%) were definite. in saoj, of the 120 (18%) eligible sports orthopaedic articles, only 41 (6%) were definite. the interobserver agreement was cohen’s kappa (κ) = 0.9 (95% ci, 0.8-0.9). as expected, the proportion of sports orthopaedic articles in saoj was lower than that in sajsm (p<0.001). there was a non-significant increase in the number of definite sports orthopaedic articles published in sajsm during the study period p=0.623 (figure 2.). in contrast, there was a non-significant decrease in the number of definite sports orthopaedic articles published in saoj during the study period (p=0.542) (figure 3). fig. 1. prisma flow diagram. sajsm, the south african journal of sports medicine; saoj, the south african orthopaedic journal review 3 sajsm vol. 34 no.1 2022 articles were classified according to the anatomical focus (table 1 and 2a and b) and also according to the sports concerned (table 3). the most frequently reported anatomical regions in sajsm were general anatomical sites (defined as more than one anatomical region), followed by specific anatomical regions namely; knee, shoulder and foot and ankle. the most frequently reported anatomical regions in saoj were specific anatomical regions, namely shoulders, cspine, foot and ankle and knee. on subgroup analysis between the four year groups in sajsm, there was a significant decrease in articles with level five evidence (p<0.001) (table 4). there was, however, no significant difference for levels one, two or three evidence between the four year groups. level one to three evidence combined showed a non-significant increase between the four year groups (p=0.040). on subgroup analysis over the three year groups in saoj, there was no significant decrease in articles with level five evidence (p=0.122). there was also no significant difference for levels one, two or three evidence over the three year groups. the articles originated from 67 universities and institutions from 61 cities in 19 countries (supplementary table 1.). in sajsm, the majority of articles were published by local/south african authors (n=44, 61%). the proportion of articles from international universities in sajsm increased during the fouryear groups and approached statistical significance (p=0.059) (figure 4). there was a non-significant difference in the proportion of articles from local and international universities in saoj between the three-year groups (p=0.569) (figure 5). discussion the present study analysed recent trends in sports orthopaedic articles published in sajsm and saoj. similar studies have been previously performed. [6-8] these studies, however, applied narrower inclusion criteria and focused only on the level of evidence. since 1980, 21% of articles published in sajsm have been definite sports orthopaedic articles. the focus of the sajsm is sports medicine and thus it is appropriate that of the 162 musculoskeletal articles published almost all were related to sports (99%). in contrast, 6% of the articles published in saoj since 2008 have been definite sports orthopaedic articles. this number increased to 18.0% when orthopaedic trauma articles relevant to sports orthopaedics were included. the sajsm has shown an increase in the number of articles published per decade since its inception. there has been a constant percentage of articles dedicated to sports orthopaedics, with no significant increase over time. in contrast, the more recent issues of saoj have shown a decrease in the absolute number of articles during its publication history. there has also been a non-significant decrease in definite sports orthopaedic articles that have been published in the saoj. this study did not investigate possible reasons for this, such as the journal’s editorial selection policy. approximately half of the articles published in saoj were published by local/ south african universities. in most of these academic institutions, sports orthopaedics is not practised as a dedicated subspeciality. this limits the opportunity for training, as well as for orthopaedic surgeons to conduct sports orthopaedic research. this then may explain the lower number of sports orthopaedic table 1. frequency of sports orthopaedic articles published in sajsm and saoj according to the anatomical focus years sajsm total sajsm sports orthopaedic sajsm specific anatomical region sajsm general saoj total saoj sports orthopaedic saoj specific anatomical region saoj general 1980-1990 128 23 (18) 17 (13) 6 (5) 1991-2000 151 32 (21) 23 (15) 9 (6) 2001-2010 178 37 (20) 18 (10) 19 (11) 166 31 (19) 29 (18) 2 (1) 2011-2021 297 70 (24) 37 (13) 33 (11) 502 89 (18) 87 (17) 2 (0.4) data are expressed as n or n (%). general was defined as more than one anatomical region. data for saoj was only available from 2008. sajsm, the south african journal of sports medicine; saoj, the south african orthopaedic journal. fig. 2. the trend of definite sports orthopaedic articles published in the south african journal of sports medicine (sajsm) between 1980 and 2021. fig. 3. the trend of definite sports orthopaedic articles published in the south african orthopaedic journal (saoj) between 2008 and 2021. review sajsm vol. 34 no.1 2022 4 articles in saoj. a review of the sports focus published in sajsm identified rugby, cricket, running and soccer as the most frequently published sports. the majority of articles, however, included more than one sports activity. in contrast, in saoj, most of the articles included were classified as ‘general’, which referred to the injuries that a sportsperson can sustain while playing sport. the second most common category was multiple sports, while only 4% of articles specified a particular sport. when one considers the frequent sports, in conjunction with the frequent anatomical regions, it appears that the focus has been on contact sports and those with a high physical demand. there may be scope for the saoj to publish more sports-specific orthopaedic topics. however, this may be limited by the number of injuries. [6] the low level of evidence in the articles published by sajsm and saoj may raise concerns. factors such as limited access to research funding and resources are possible contributors among local authors. nonetheless, over the year groups, articles with level v evidence published by sajsm decreased significantly. in keeping with this trend, articles with level v evidence published by saoj have also shown a decline, albeit non-significant. orthopaedic journals with a higher impact factor are more likely to publish level i or 2 articles. [9] there have been a number of authors who do acknowledge the place of level 3 and 4 evidence and we, therefore, support the continued publishing of these studies. [6,10,11] however, authors should be encouraged to include control groups and to try and aim for a higher level of evidence. [10,11] both journals showed a wide geographical and academic base of authors. the majority were published by the university of cape town. in sajsm, articles were mainly published by authors from south africa. this highlights the local relevance of the research published by sajsm. it is interesting to note, however, that the proportion of articles from international table 2. anatomical focus of sports orthopaedic articles published in sajsm and saoj anatomical region sajsm saoj total c-spine 7 (4) 14 (12) 21 (8) t-spine 1 (0.6) 1 (1) 2 (1) l-spine 7 (4) 3 (3) 10 (4) sacrum 2 (1) 2 (2) 4 (1) shoulder 16 (10) 28 (23) 44 (16) humerus 0 (0) 0 (0) 0 (0) elbow 2 (1) 4 (3) 6 (2) radius/ulna 1 (0.6) 2 (2) 3 (1) wrist and hand 0 (0) 11 (9) 11 (4) pelvis 3 (2) 0 (0) 3 (1) hip 7 (4) 3 (3) 10 (4) femur 2 (1) 3 (3) 5 (2) knee 24 (15) 18 (15) 42 (15) tibia/fibula and compartments 5 (3) 7 (6) 12 (4) ankle and foot 12 (7) 19 (16) 31 (11) general 73 (45) 5 (4) 78 (28) data are expressed as n (%). general was defined as more than one anatomical region. sajsm, the south african journal of sports medicine; saoj, the south african orthopaedic journal. table 3. frequency of sports orthopaedic articles published in sajsm and saoj according to sport sport sajsm saoj total running 15 (9) 1 (1) 16 (6) cricket 24 (15) 0 (0) 24 (9) rugby 34 (21) 0 (0) 34 (12) tennis 2 (1) 0 (0) 2 (1) dancing 1 (1) 0 (0) 1 (0.4) gymnastics 1 (1) 0 (0) 1 (0.4) aerobics 1 (1) 0 (0) 1 (0.4) soccer 11 (7) 0 (0) 11 (4) multiple sports 44 (27) 27 (23) 71 (25) military 2 (1) 1(0.8) 3 (1) baseball 1 (1) 0 (0) 1 (0.4) hockey 3 (2) 0 (0) 3 (1) cycling 4 (3) 1 (1) 5 (2) basketball 4 (3) 0 (0) 4 (1) olympics 2 (1) 0 (0) 2 (1) volleyball 1 (1) 0 (0) 1 (0.4) swimming 1 (1) 0 (0) 1 (0.4) squash 1 (1) 0 (0) 1 (0.4) golf 2 (1) 0 (0) 2 (1) karate 0 (0) 1 (1) 1 (0.4) paralympics 1 (1) 0 (0) 1 (0.4) rowing 2 (1) 0 (0) 2 (1) mixed martial arts 1 (1) 0 (0) 1 (0.4) ironman 1 (1) 0 (0) 1 (0.4) wheelchair basketball 1 (1) 0 (0) 1 (0.4) netball 1 (1) 0 (0) 1 (0.4) ringball 1 (1) 0 (0) 1 (0.4) horse riding 0 (0) 1 (1) 1 (0.4) general orthopaedics 0 (0) 88 (73) 88 (31) data are expressed as n (%). general orthopaedics referred to injuries that a sportsperson can sustain while playing sport without mention of a specific sport. sajsm, the south african journal of sports medicine; saoj, the south african orthopaedic journal. table 4. level of evidence of sports orthopaedic articles published in sajsm and saoj sajsm years total level 1 level 2 level 3 level 4 level 5 1980-1990 17 0 (0) 4 (24) 0 (0) 1 (6) 12 (70.6) 1991-2000 37 0 (0) 5 (14) 5 (14) 8 (22) 19 (51.4) 2001-2010 36 0 (0) 10 (28) 10 (28) 13 (36) 3 (8.3) 2011-2021 71 4 (6) 14 (20) 12 (17) 29 (41) 12 (16.9) saoj years total level 1 level 2 level 3 level 4 level 5 2008-2012 46 1 (2) 1 (2) 3 (7) 19 (41) 22 (48) 2013-2017 49 2 (4) 2 (4) 6 (12) 22 (45) 17 (35) 2018-2021 25 1 (4) 0 (0) 0 (0) 18 (72) 6 (24) data are expressed as n or n (%). level 1 refers to systematic review of randomised trials; level 2 refers to randomised trials; level 3 refers to nonrandomised trials/cohort studies; level 4 refers to case-series, case-control, or historically controlled studies; level 5 refers to expert opinion. sajsm, the south african journal of sports medicine; saoj, the south african orthopaedic journal. review 5 sajsm vol. 34 no.1 2022 universities increased over time. in contrast, articles in saoj were from both local and international universities. the results of this review must be interpreted in the light of certain limitations. firstly, while articles for sajsm were available from 1980, articles for saoj were only available from 2008, which limits comparison. secondly, this study investigated the level of evidence. in all articles for sajsm and saoj (2008 to 2017), no level of evidence was available, and the articles were reviewed and assigned a level of evidence based on the oecbm. [5] however, these articles were discussed and reviewed by two independent reviewers. furthermore, previous studies have demonstrated acceptable interobserver agreement between epidemiologyand nonepidemiology-trained reviewers. [11,12] lastly, this review was limited to sajsm and saoj only and we did not search the international literature to assess the number of south african sports orthopaedics articles which were published in international journals. conclusion this narrative review analysed the publishing trends for sports orthopaedics in two relevant south african journals, namely, sajsm and saoj. we describe a wide range of data including anatomical regions, sports, level of evidence and origin of the authors, which highlights areas of strength and weakness. it was promising to note a decrease in the proportion of level v evidence. the focus, in particular of sajsm, is relevant to south africa’s popular sports and injury patterns. the majority of articles published in sajsm were from local authors, which highlights the importance of publishing research specific to south africa, the relevant sports played in our country, and the healthcare resources for sports people. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: bg: study design, manuscript author, data analysis; dl: data collection and entry and critical review; es: data analysis and critical review. references 1. discovery vitality. the science of vitality journal. south africa: discovery, 2022. [https://www.discovery.co.za] (accessed 4 july 2022). 2. momentum metropolitan holdings limited. momentum multiply. south africa. momentum, 2021. [https://www.multiply.co.za/ engaged] (accessed 4 july 2022). 3. south african journal of sports medicine. [https:// journals.assaf.org.za/index.php/sajsm] (accessed 26 october 2021). 4. south african orthopaedic journal. [https://www.saoj.org.za/ index.php/saoj] (accessed 26 october 2021). 5. oxford centre for evidence-based medicine: levels of evidence. university of oxford. 2022. [https://www.cebm.ox.ac.uk/ resources/levels-of-evidence] (accessed 26 october 2021). 6. cvetanovich gl, fillingham ya, harris jd, erickson bj, verma nn, bach br, jr. publication and level of evidence trends in the american journal of sports medicine from 1996 to 2011. am j sports med 2015;43(1):220-225. [doi.org/ 10.1177/0363546514528790] [pmid: 24723417] 7. hanzlik s, mahabir rc, baynosa rc, khiabani kt. levels of evidence in research published in the journal of bone and joint surgery (american volume) over the last thirty years. j bone joint surg am 2009;91(2):425-428. [doi.org/10.2106/jbjs.h.00108] [pmid: 19181987] 8. judy rp, shin jj, mccrum c, ayeni or, samuelsson k, musahl v. level of evidence and authorship trends of clinical studies in knee surgery, sports traumatology, arthroscopy, 1995-2015. knee surg sports traumatol arthrosc 2018;26(1):9-14. [doi.org/ 10.1007/s00167-017-4801-6] [pmid: 29138917] 9. obremskey wt, pappas n, attallah-wasif e, tornetta p 3rd, bhandari m. level of evidence in orthopaedic journals. j bone joint surg am 2005;87(12):2632-2638. [doi.org/ 10.2106/jbjs.e.00370] [pmid: 16322612] 10. wupperman r, davis r, obremskey wt. level of evidence in spine compared to other orthopedic journals. spine (phila pa 1976) 2007;32(3):388-393. [doi.org/ 10.1097/01.brs.0000254109.12449.6c] [pmid: 17268275] 11. zaidi r, abbassian a, cro s, guha a, cullen n, singh d, et al. levels of evidence in foot and ankle surgery literature: progress from 2000 to 2010? j bone joint surg am 2012;94(15):e1121-1210. [doi.org/ 10.2106/jbjs.k.01453] [pmid: 22855001] 12. bhandari m, swiontkowski mf, einhorn ta, tornetta p 3rd, schemitsch eh, leece p, et al. interobserver agreement in the application of levels of evidence to scientific papers in the american volume of the journal of bone and joint surgery. j bone joint surg am 2004;86(8):1717-1720. [doi.org/ 10.2106/00004623200408000-00016] [pmid: 15292420] fig. 4. the proportion of local and international universities publishing in sajsm fig. 5. the proportion of local and international universities publishing in saoj https://www.discovery.co.za/ https://www.multiply.co.za/%20engaged https://www.multiply.co.za/%20engaged https://www.saoj.org.za/%20index.php/saoj https://www.saoj.org.za/%20index.php/saoj 102 sajsm vol. 27 no. 4 2015 original research post-exercise ingestion of a carbohydrate and casein hydrolysate supplement reduces perceived muscle soreness but not fatigue in sevens rugby players a n bosch,1 phd; l-d hill,1 bsc (med)(hons); e jordaan,2 msc 1 division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, south africa 2 biostatistics unit, medical research council, south africa corresponding author: a n bosch (andrew.bosch@uct.ac.za) objectives. this study investigated the effects of prolonged use of a protein (casein hydrolysate) supplement on perceived muscle soreness and fatigue, in international level sevens rugby players (n=23) during a pre-season training camp. methods. a randomised, double-blind, placebo-controlled design was used. players were assigned to a carbohydrate-only or an isocaloric carbohydrate and protein supplement and ingested the assigned supplement after each training session (17 field training sessions over a 23-day period). before each training session a questionnaire and 10-point visual analogue scale was completed that assessed muscle soreness and muscle fatigue in the calf, hamstring, and quadriceps. results. no significant differences were observed in leg fatigue in any of the muscle groups. however, muscle soreness was significantly lower in the experimental group in the quadriceps at week 3, day 5 (p=0.04) and calves at week 4, day 2 (p=0.02) and day 3 (p=0.04). additionally, no significant differences were found during the heart rate interval monitoring system test (p=0.350) used to determine training load recovery. conclusion. the results suggest that prolonged use of a protein hydrolysate supplement may be beneficial in reducing muscle soreness, but not muscle fatigue, during periods of continuous high training loads. keywords. supplement, protein feeding, recovery s afr j sports med 2015;27(4):102-107. doi:10.17159/2078-516x/2015/ v27i4a437 with the increased emphasis on achieving success in both recreational and professional sport, nutritional strategies to improve performance and enhance recovery have been the focus of considerable research. previous studies have shown that protein supplementation during or post exercise positively affects several factors related to recovery, such as a reduction in the subjective rating of muscle soreness and fatigue.[1–3] delayed onset muscle soreness (doms) can compromise performance and training due to pain and a reduction in joint range of mostion, shock attenuation and peak torque.[4] muscle fatigue following hard training is common, and if not managed correctly, can result in overreaching or overtraining syndromes.[4] a period of reduced training load between hard training sessions is therefore necessary to allow recovery. this, however, limits the number of key workouts that an athlete can perform each week. enhancing recovery through nutritional means by reducing either doms or muscle fatigue, or both, would permit an athlete to recover faster and be able to train at a high intensity more frequently. previous studies have shown that protein supplementation either during or post exercise positively affects several factors related to recovery, including a reduction in the subjective rating of muscle soreness.[5,6] on the other hand, a number of studies have failed to show any potential beneficial effect on muscle soreness or muscle fatigue.[3,7,8] despite these inconsistencies in findings related to doms and fatigue, when performance has been investigated, several studies have shown that post-exercise protein supplementation improves subsequent performance[9-11] although, as with doms and fatigue, some studies have shown no positive effect.[3,7] importantly, the majority of studies have only assessed the effect of protein ingestion on recovery after an initial or second bout of exercise, or over a relatively short period of time. training is a longterm process in which athletes gradually adapt to progressively higher training loads and physical demands. thus assessing the longterm effects of protein supplementation appears logical. however, there are only a handful of studies investigating long-term effects of protein supplementation on post-exercise recovery.[5,12–14] flakoll et al.[13] assessed post-exercise protein supplementation in us marine recruits during basic military training over 54 days. both at day 34 (6 mile full gear hike) and day 54 (final physical fitness test), protein supplementation resulted in a significant reduction in muscle soreness as well as other outcomes, such as a decreased total number of medical visits. furthermore, a study by witard et al.[14] examined the effect of increased protein intake on short-term decrements in endurance performance during a block of high-intensity training. well-trained cyclists completed two 3-week trials in which participants were divided equally into normal, intensified or recovery training. cyclists received either a high-protein (protein; 3 g protein·kg−1 body mass (bm) d−1) or a normal diet (control; 1.5 g protein·kg−1 bm d−1) during intense training and recovery. increased dietary protein intake led to a possible attenuation (4.3%; 90% confidence limits ×/÷5.4%) in the decrement in time trial performance after a block of high-intensity training compared with normal (protein = 2639 ± 350 s; control = 2555 ± 313 s). restoration of endurance performance during recovery training possibly benefited (2.0%; ×/÷4.9%) from additional protein intake. additional protein intake reduced symptoms of psychological stress and may have resulted in a worthwhile amelioration of the performance decline experienced during a block of high-intensity training. furthermore, goh et al.[15] found no difference in the perception of muscle fatigue and muscle soreness between different compositions of carbohydrate (cho) and protein (pro) drinks during prolonged cycling exercise. however, these studies are limited due to their short duration. thus, the evidence regarding the effect of prolonged protein supplementation on recovery and performance remains limited. the current study therefore aimed to determine the effects of prolonged ingestion of a cho + casein hydrolysate (cho + pro) supplement post-exercise on perceived levels of doms and muscle fatigue, in international level sevens rugby players participating in a 23-day pre-season training camp. the authors hypothesised that cho + pro supplementation would result in reduced levels of mailto:andrew.bosch@uct.ac.za http://dx.doi.org/10.17159/2078-516x/2015/v27i4a437 http://dx.doi.org/10.17159/2078-516x/2015/v27i4a437 sajsm vol. 27 no. 4 2015 103 doms and perceived muscle fatigue, as compared to cho-only supplementation. methods study participants the entire training group of the international level sevens rugby players, who were attending a pre-season training camp, agreed to participate in the study. players were randomly divided from a list of names into either a control (n=10) or experimental (n=13) group, in a double-blind, placebo-controlled design. additionally, all players in the two groups were matched by playing position and fitness level. there were no significant differences between the two groups in mass, height, percentage body fat or lean mass (table 1). all the players participating in the study lived at a facility on-site (thus the same meal choices were provided to all the players for the duration of the study). although the macronutrient intake of the meals was not controlled (i.e. the players were free to choose from the available foods served at each meal), prior to the start of the training camp all the players were given a detailed lecture by a qualified sports dietician on guidelines to achieve good sports nutrition, including the meeting of adequate carbohydrate and protein requirements. although no dietary records were completed by the players, players received strict instructions not consume any additional supplements during the training camp. table 1. no significant differences were found in mass, height, body fat percentage and lean mass between the experimental and control groups experimental (n=13) control (n=10) mass (kg ± sd) 85.7 ± 8.4 89.9 ± 11.8 p=0.368 height (cm ± sd) 179.1 ± 4.0 180.3 ± 5.8 p=0.632 body fat (% ± sd) 13.5 ± 2.82 12.7 ± 2.8 p=0.499 lean mass (kg ± sd) 77.7 ± 7.9 76.72 ± 10.1 p=0.795 before the study, all participants received a detailed outline of the study procedure and were required to sign an informed consent form in accordance with the declaration of helsinki (seoul, october 2008) before entry into the study, which was approved by the research ethics committee of the faculty of health sciences of the university of cape town. all information collected during this study was kept confidential and anonymity was ensured via a participant coding system. all data collected were stored on a password-protected system. all the participants received a detailed report of the overall study findings but did not receive their individual results. training the training load (fig. 1) was standardised by the coach for all the players taking part in the training camp. all players in both groups completed identical workouts (resistance and field training) consisting of a programme designed by the coaching staff and was strictly controlled (table 1). resistance training comprised strength exercises (including squat variations, vertical push, vertical pull, horizontal push, horizontal pull, power clean, push press, chest press, bicep and triceps exercise variations) and field training (including skills training) comprised of attack and defensive patterns, general rugby skills (lineouts, scrumming, ball handling and passing) and rugby-specific fitness conditioning (40 m sprints, ruck-specific conditioning and tackling). during each training session, details of time, intensity, and type (resistance or field training) were recorded to give an overall numerical value (session value) for each of the total of 17 sessions over the 23-day period. no data were collected during the weekends as these were rest days assigned by the coaches, during which no training took place. fig. 1. total weekly training load and average daily training load for each week as calculated by session rpe (min x rpe) over the duration of the training camp. initial measurements: anthropometry the standard anthropometric data of weight (kg), stature (cm) and skinfolds (triceps, bicep, subscapular, suprailiac) were measured by the same qualified biokineticist using the isak technique (international society for the advancement of kinanthropometry[16]). the skinfold measurements were subsequently used to calculate lean body mass and percent body fat.[16] protein supplement/intervention immediately after each field and resistance training session the players ingested either a carbohydrate (0.8 g/kg body mass) plus protein (casein hydrolysate) (0.4 g/kg body mass; containing di and tripeptides) supplement (peptopro, dsm, the netherlands), or an isocaloric placebo carbohydrate-only drink (1.2 g/kg body mass), dissolved in 500 ml water. both drinks contained the same carbohydrate base consisting of maltodextrin (table 2). additionally, each batch of the supplement was tested for contaminants by an independent laboratory. the drinks were mixed individually for each player by a research assistant who was blinded to the drink’s content, and intake by the players was monitored by the coach. no other supplements were used for the duration of the training camp. 104 sajsm vol. 27 no. 4 2015 table 2. nutritional content of the test beverages protein (pro + cho/100 g) placebo (cho/100 g) energy (kj) 1656 1658 protein (casein hydrolysate) 18.5 g nil carbohydrate (maltodextrin) 36.4 53 g total fat nil nil sodium chloride 205 mg 205 mg testing protocol/measurements data were collected via a self-administered questionnaire including a 1-10 visual analogue scale targeting perception of muscle soreness and muscle fatigue as has been used in previous research[17,18] and shown to be valid and reliable. specifically, perceived muscle soreness and muscle fatigue were assessed in three different muscle groups (quadriceps, hamstrings, and gastrocnemius), under four different conditions in this study. the conditions were as follows; (1) at rest (i.e. when the muscle is not active), (2) during daily activity (such as walking to and from rooms or field), (3) when a stretch was applied (the player completed a stretch of the muscle group and reported immediately the pain or fatigue experienced) and (4) before the commencement of training. the questionnaire and analogue scale were completed at the same time of day, before each field training session, and before any other activities (i.e. warm-up or stretching). both doms and muscle fatigue were rated on a scale of 1-10 (10-point scale using 1 unit intervals) with 1 being none, and 10 being severe.[19] heart rate interval monitoring system test (hims) the hims[19] is a standardised multistage submaximal test used to quantify the variation in heart rate under controlled conditions so that training-induced changes in submaximal heart rate can be interpreted more precisely. heart rate recovery is the rate at which heart rate decreases, usually in the first minute or two, after moderate to heavy exercise and is a consequence of parasympathetic reactivation and sympathetic withdrawal.[19] after a standardised stretching warm-up, all participants were fitted with a heart rate transmitter and wrist monitor recorder (polar accurex, polar electro, kempele, finland) before the start of the test. the heart rate monitor measured the heart rate every five seconds during the test which consisted of a submaximal shuttle run test of four increasing intensity stages, interspersed with one minute recovery periods. the participants were required to run between two lines that were 20 m apart, the pace of running within each of the four stages (8.4, 9.6, 10.8, and 12.0 km h-1, respectively) being set by a pre-recorded auditory signal. each stage lasted two minutes, followed by the one minute of recovery. the participants then rested for two minutes after the fourth stage, during which hr was recorded. this test was designed to be submaximal and nonaversive for the participants so that from a practical perspective the test could be administered frequently during different phases of training without influencing the training outcome. the recorded hr was transferred to a computer using an interface (polar electro). the heart rate for each stage was recorded for the final 15 seconds. the heart rate for each recovery period was determined in the same way. during the recovery period after the fourth stage, the heart rate was recorded at one and two minutes, respectively. these heart rates were expressed as a percentage of the heart rate measured during the fourth stage and defined as recovery percentage (%) first minute and recovery percentage (%) second minute, respectively.[19] data analysis to test the significance of the treatment effect (post-exercise supplementation with a cho + pro drink vs. an isocaloric cho-only drink) on each muscle group and each outcome (doms and fatigue), a mixed model was fitted with random effects for player, player x week and player x day. a mixed model approach was used due to the multiple data for the same players over the 17 days and to accommodate any missing data. for each muscle group, the 4-way interaction model including “condition” (rest, daily activity, stretch, pressure) was used. supplement (casein hydrolysate and placebo), week, and day showed that the 4-way interaction with “condition” was not significant (quadriceps: p=0.953, hamstrings: p=0.967, calf: p=0.997), indicating that the treatment effect was similar for all conditions. this resulted in the fitting of a 3-way mixed model for each outcome and each muscle group. the type 3 tests of fixed effects (f value, p) were considered for overall significance of the treatment effect. conditional on the overall test being significant, suitable contrasts were set up to test the significance of the treatment effect over the 17 testing days individually. least squares means were used to summarise the size of the treatment effects. for all assessments the level for statistical significance was set at p<0.05. in addition, a second mixed model was fitted in which the measurements at baseline (day 1 of each week), were subtracted out at each subsequent day for that week. results analysis of muscle fatigue data (figs. 2-4) showed that the overall 3-way interactions of week x day x drink for all three muscle groups were not significant (quadriceps, p=0.48; hamstrings, p=0.53; calves, p=0.67; legs, p=0.18) at any time during the experimental period. analysis of muscle soreness data (figs. 5-7) showed that the 3-way interaction of week x day x drink was significant for two muscle groups (quadriceps, p<0.0001; calves p=0.016). various contrasts (post-hoc tests) were set up to compare the two groups for effect of drink type. these contrasts compared the muscle soreness score for groups at each of the 17  time points (week 1, days 1-4; week 2, days 1-5; week 3, days 1-5; week 4, days 1-3). significant differences were observed for the calves (fig. 4) at week 4, day 2 (estimated effect=1.2; se=0.50; p=0.02) and day 3 (estimated effect=1.0; se=0.49; p=0.04) and quadriceps at week 3 (fig. 5), day 5 (estimated effect=1.0; se=0.49; p=0.04). each mean value in the figures represents 52 observations for the experimental group and 40 for the control group. no significant difference (p=0.350) was found between the type of drink ingested and heart rate recovery at each at each of the three hims testing points (fig. 8). sajsm vol. 27 no. 4 2015 105 fig. 2. fatigue scores in the control and experimental groups in the quadriceps. there were no significant differences (n=10 in the experimental group and 13 in the control group). fig. 3. fatigue scores in the control and experimental groups in the hamstrings. there were no signi ficant differences (n=10 in the experimental group and 13 in the control group). fig. 4. fatigue scores in the control and experimental groups  in the calves. there were no signi fi cant differen ces (n=10 in the experimental group and 13 in the control group). fig. 5. pain scores in the control and experimental groups in the quadriceps. significant differences were observed at day 18 (p=0.04) * = p<0.05. significant differences from baseline were found at day 18 (p=0.0063) # = p<0.05. fig. 6. pain scores in the control and experimental groups in the hamstrings. there were no significant differences. fig. 7. pain scores in the control and experi mental groups in the calves. significant differences were observed at day 22 (p=0.02) and day 23 (p=0.04) * = p<0.05. significant differ ences from baseline were found at day 23 in the calves (p=0.0011) # = p<0.0. fig. 8. heart rate recovery (bpm) for the experimental and control groups. no significant differences were detected between the different beverage groups during each of the hims testing periods (p=0.350). however, hr recovery tended towards significance at week 1 (p=0.095) and at week 3 (p=0.0665). error bars indicate sem. discussion the first important finding of this study was that towards the end of the study period, doms was perceived to be lower in the quadriceps and calf muscles of the players who ingested the cho + pro supplement, compared to those players who ingested an isocaloric cho-only control drink (figs. 5-7). the effect was estimated to be about one unit (on the 1-10 point scale[17,18]), which could potentially have short-term practical implications from a training perspective, as well as long-term implications in the adaptation of muscle to training load. this effect was first noticeable at the end of the third week of camp when the cumulative training load may have reached a critical level. 106 sajsm vol. 27 no. 4 2015 to the best of the authors’ knowledge, there are only a few studies investigating long-term effects of protein supplementation on postexercise recovery.[12–14] the study by flakoll et al.[13] assessed the effect of post-exercise protein supplementation in us marine recruits during basic military training over 54  days. as in luden et al.,[5] protein supplementation resulted in a significant reduction in muscle soreness. unfortunately, in both of these studies the experimental treatment was not isocaloric with the control, making it impossible to determine whether the observed treatment was due to the protein supplement or additional energy supplied by the protein-containing drink. in a more carefully balanced study by witard et al.,[14] the effect of increased protein intake on short term decrements in endurance performance during a block of high-intensity training was examined. well-trained cyclists completed two 3-week trials sequentially consisting of one week of normal training, one week of intensified training and one week of recovery training. cyclists were prescribed either a high-protein or a normal diet during intensified and recovery training periods. increased dietary protein intake led to a possible attenuation (4.3%; 90% confidence limits ±5.4%) in the decrement in time trial performance (time to complete set amount of work) after a block of high-intensity training compared with a normal (control) diet (protein = 2639 ± 350 s; control = 2555 ± 313 s). restoration of endurance performance during recovery training possibly benefited (2.0%; ±4.9%) from additional protein intake. in the current study, the positive effect of the cho + pro supplement was noticeable after a much longer period of supplementation use than in previous studies, in which a cho + pro supplement has often been ingested on only one occasion post-exercise. interestingly, the reduction in doms in specific muscle groups within the experimental group could be aligned to preceding training sessions. reduced doms in the quadriceps on day 5 in week 3 (fig. 5), was preceded by two training sessions that specifically targeted the quadriceps on days 1 and 2 of that week. similarly, reduced doms in the calf muscles was observed on days 2 and 3 of week 4 (fig. 7), after two training sessions in which the calves were particularly targeted. perceived muscle soreness scores did not increase significantly from baseline in the players who ingested the cho + pro supplement, whereas those players who ingested the cho-only supplement, had a significant increase in doms above baseline over the study duration. a reduction in doms in athletes who train rigorously and are at an elite level is critically important from a training perspective. previous research has shown that muscle soreness can severely impair athletic performance.[17] twist et al.[20] showed that a prolonged increase in perceived muscle soreness and fatigue have critical implications on the quality of training performed by players in the 48 h after a rugby league match. the authors found significant changes in creatine kinase concentrations, perceptual measures of fatigue, muscle soreness, attitude to training, and countermovement jump height flight time of the players 24 h and 48 h post-match. consequently, perceptual muscle soreness and fatigue is a significant modifying factor in a player’s exercise tolerance and attitude towards training.[21] in this study, where players were required to exercise rigorously for an extended period of time (23-day pre-season camp), the perception of muscle soreness increased in players ingesting the placebo. the second notable finding of this study was that there was no significant effect observed on muscle fatigue (figs. 2-4) between the two groups despite the differences in doms. muscle fatigue therefore appears to not be affected by protein ingestion, at least under the current experimental conditions, and suggests that other factors may play a more important role in relation to muscle fatigue. recently, goh et al.[15] found no difference in perceptions of muscle fatigue and muscle soreness between different compositions of cho + pro drinks during prolonged cycling exercise. furthermore, gilson and colleagues[6] found no effects on myoglobin concentration, muscle soreness, fatigue ratings and isometric quadriceps force between participants who ingested either a carbohydrate drink or isocaloric chocolate milk drink as a recovery beverage. the lack of treatment effect on fatigue observed in this present study and in previous research[7,8] may be, in part, due to investigations being conducted on elite-level athletes. therefore, in the current study, the lack of difference in perception of muscle fatigue may be due to the high level of conditioning of the players.[22] it is possible that doms and perceived levels of muscle fatigue are governed by different mechanisms. finally, to accurately monitor changes in training load and heart rate recovery of the players during the 23-day training camp, the hims test was implemented as it is easy to administer, noninvasive and sensitive to change.[19] the final finding of this study was that there were no differences found between the experimental and control groups with regards to heart rate recovery (fig. 8) as measured by the hims test, although hr recovery tended towards significance at week 1 (p=0.095) and at week 3 (p=0.0665). this may be attributed to the increase in training load over the course of the camp being carefully monitored by the coaching staff, thus leading to appropriate changes in load to prevent over training.[4] limitations to the best of these authors’ knowledge, the participants in this study did not consume additional macronutrients or supplements, as they were strictly instructed not to do so. however, it is possible that some may have consumed additional macronutrients without the authors’ knowledge. additionally, the daily macronutrient intake of the meals provided at the facility was not strictly controlled, with the players able to choose from the available foods served at each meal. also, the players did not keep a dietary record. the authors therefore had to interpret the results with caution. furthermore, due to the nature of this study, where the research participants were elite international sevens rugby players, they were not willing to consent to the taking of blood samples, and the authors were unable to obtain any biochemical data, such as ck concentrations. future research needs to be conducted whereby the parameters of the study are more strictly controlled so that the risk of confounding variables is reduced. in conclusion, the results of this study suggest that during a period of increasing cumulative training load, post-exercise ingestion of a cho + pro supplement reduces doms, but not fatigue. thus the effect of protein supplementation on doms and fatigue appears to be different. post-exercise ingestion of cho + pro may therefore have a long-term beneficial effect by reducing doms and perceived muscle soreness as a consequence of cumulative training load. sajsm vol. 27 no. 4 2015 107 practical applications • coaches can better inform players about the benefits of protein supplementation and improved nutritional standards for peak performance. • supplementation of cho+pro following exercise may reduce perceived symptoms of pain in subsequent exercise. • long-term supplementation of cho+pro may improve exercise ability as more high intensity and demanding training sessions can be completed in a shorter amount of time. acknowledgements. this study was  supported by dsm nutritional products south africa (pty) ltd. who supplied the protein hydrolysate. references 1. ivy jl, res pt, sprague rc, et al. effect of a carbohydrate-protein supplement on endurance performance during exercise of varying intensity. int j sport nutr exerc metab 2003;13(3):382-395. pmid: 14669937. 2. saunders m. coingestion of carbohydrate-protein during endurance exercise: influence on performance and recovery. int j sport nutr exerc metab 2007;17: suppl: s87-103. pmid: 18577778. issn: 1543-2742. 3. breen l, tipton kd, jeukendrup ae. no effect of carbohydrate-protein on cycling performance and indices of recovery. med sci sport exerc 2010;42(6):1140-1148. [http://dx.doi.org/10.1249/mss.0b013e3181c91f1a] 4. hawley cj, schoene r. overtraining syndrome: a guide to diagnosis, treatment, and prevention. phys sport 2003;31(6):25-31. [http://dx.doi.org/10.3810/psm.2003.06.396] 5. luden nd, saunders mj, todd m. postexercise carbohydrate-proteinantioxidant ingestion decreases plasma creatine kinase and muscle soreness. int j sport nutr exerc metab 2007;17:109-123. pmid: 17460336. issn: 1526-484x. 6. gilson sf, saunders mj, moran cw, et al. effects of chocolate milk consumption on markers of muscle recovery following soccer training: a randomized cross-over study. j int soc sport nutr 2010;18:7-19. [http://dx.doi.org/10.1186/1550-2783-7-19] 7. berardi jm, noreen ee, lemon pw. recovery from a cycling time trial is enhanced with carbohydrate-protein supplementation vs. isoenergetic carbohydrate supplementation. j int soc sport nutr 2008;24(5):24. [http://dx.doi.org/10.1186/1550-2783-5-24] 8. roberts sp, stokes ka, trewartha g, et al. effect of combined carbohydrate-protein ingestion on markers of recovery after simulated rugby union match-play. j sport sci 2011;29(12):1253-1262. [http://dx.doi.org/10.1080/02640414.2011.587194] 9. saunders mj, moore rw, kies ak, et al. carbohydrate and protein hydrolysate coingestions improvement of late-exercise time-trial performance. int j sport nutr exerc 2009;19:136-149. pmid: 19478339. issn: 1526-484x. 10. moore rw, saunders mj, pratt ca, et al. improved time to exhaustion with carbohydrate-protein hydrolystate beverage. med sci sport exerc 2007;supplement:s89-90. 11. coyle cj, donne b, mahony n. effects of carbohydrate-protein ingestion postresistance training in male rugby players. int j exerc sci 2012;5(1). 12. ferguson-stegall l, mccleave e, ding z, et al. aerobic exercise training adaptations are increased by postexercise carbohydrate-protein supplementation. j nutr metab 2011. [http://dx.doi.org/10.1155/2011/623182] 13. flakoll pj, judy t, flinn k, et al. postexercise protein supplementation improves health and muscle soreness during basic military training in marine recruits. j appl physiol 1996;96(3):951-956. [http://dx.doi.org/10.1152/japplphysiol.00811.2003] 14. witard oc, jackman sr, kies ak, et al. effect of increased dietary protein on tolerance to intensified training. med sci sport exerc 2011;43(4):598-607. [http:// dx.doi.org/10.1249/mss.0b013e3181f684c9] 15. goh q, boop ca, luden nd, et al. recovery from cycling exercise: effects  of carbohydrate and protein beverages. nutr 2012;4:568-584. [http://dx.doi.org/10.3390/ nu4070568] 16. durnin jvga, womersley j. body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481  men and women aged from 16 to 72 years. br j nutr 1974;32(1):77-97. pmid: 4843734. issn: 0029-6651. 17. burgess tl, lambert mi. differences in muscle pain and plasma creatine kinase activity after “up” and “down” comrades marathons. south african j sport med 2008; 20(2):54-58. 18. plattner k, lambert mi, tam n, et al. the response of cortical alpha activity to pain and neuromuscular changes caused by exercise-induced muscle damage. scand j med sci sport 2014;24(1):166-178. [http://dx.doi.org/10.1111/j.1600-0838.2012.01486.x] 19. lamberts rp, lambert mi. day-to-day variation in heart at different levels of submaximal exertion: implications for monitoring training. j str cond res 2010; 23(3):1005-1010. [http://dx.doi.org/10.1519/jsc.0b013e3181a2dcdc] 20. twist c, eston r. the effect of exercise-induced muscle damage on perceived exertion and cycling endurance performance. eur j appl physiol 2009;105(4):559-567. [http:// dx.doi.org/10.1007/s00421-008-0935-z] 21. twist c, waldron m, highton j, et al. neuromuscular, biochemical and perceptual post-match fatigue in professional rugby league forwards and backs. j sport sci 2012;30(4):359-367. [http://dx.doi.org/10.1080/02640414.2011.640707] 22. higham dg, pyne db, anson jm, et al. movement patterns in rugby sevens: effects of tournament level, fatigue and substitute players. j sci med sport 2012;15(3):277-282. [http://dx.doi.org/10.1016/j.jsams.2011.11.256] http://dx.doi.org/10.1249/mss.0b013e3181c91f1a http://dx.doi.org/10.3810/psm.2003.06.396 http://dx.doi.org/10.1186/1550-2783-7‑19 http://dx.doi.org/10.1186/1550-2783-5‑24 http://dx.doi.org/10.1080/02640414.2011.587194 http://dx.doi.org/10.1155/2011/623182 http://dx.doi.org/10.1152/japplphysiol.00811.2003 http://dx.doi.org/10.1249/mss.0b013e3181f684c9 http://dx.doi.org/10.1249/mss.0b013e3181f684c9 http://dx.doi.org/10.3390/nu4070568 http://dx.doi.org/10.3390/nu4070568 http://dx.doi.org/10.1111/j.1600-0838.2012.01486.x http://dx.doi.org/10.1519/jsc.0b013e3181a2dcdc http://dx.doi.org/10.1007/s00421-008-0935‑z http://dx.doi.org/10.1007/s00421-008-0935‑z http://dx.doi.org/10.1080/02640414.2011.640707 http://dx.doi.org/10.1016/j.jsams.2011.11.256 _goback original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license prevalence and associated factors with mental health symptoms among semi-professional cricket players after the resumption of sporting activities following an extensive lockdown l malele, mphil; h noorbhai, phd department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa corresponding author: l malele (shaz.malele.sm@gmail.com) cricket is considered one of the most demanding team sports in terms of athleticism and skill. [1] in addition to the physical load, it also carries high psychosocial stress that affects the player both during and after the game. [1, 2] even though more cricket players are revealing what they experience, mental health illness is still stigmatised. [2, 3] the mental health of cricket players across the globe has been a topic of debate for a considerable time. [1, 2, 3] the athlete's mental status, similar to their physical status, can be viewed as a resource that allows players to cope with the pressures of the game [4] the reluctance of cricket players to speak freely about their mental health demonstrates inadequate access to mental health care in industrialised and especially, underdeveloped nations. [1] several studies have been published so far on the topic of cricket and mental health. [2,4,5] ogden et al. conducted a qualitative investigation of mental health among professional cricket players in the united kingdom. they documented that perceived mental health stigma can be reduced by providing stability with player contracts, helping players prepare for transitions, encouraging healthy habit development, as well as optimal coach relationships and communication. [4] similar to the present study, hendricks et al. conducted a cross-sectional survey design to determine the prevalence of anxiety and depression symptoms in professional cricket players, as well as to identify factors associated with symptoms of anxiety and depression. [5] their study showed that the prevalence of symptoms of anxiety and depression was 59% and that both the contributing and protective factors were career-related, which can be modifiable. [5] both studies have suggested that further research is required to help build a greater base of understanding of mental health in cricket in order to assist with the development of interventions, maximise the impact of psychological practice within cricket, as well as the inclusion of associated factors into mental health literacy programmes. [4,5] during the pandemic, athletes’ lifestyles were disrupted, which led to additional mental health stressors. [3] changes in the way we have adjusted to the new normal (digital technologies, lessons from lockdown, etc.) and the inability to train normally are just some of the challenges athletes have had to endure due to the covid-19 pandemic. [6] according to dass–21, an increase in certain emotions, such as anxiety, can result in improved performance. [8] in addition, the importance of self-awareness and continuous mental health promotion among elite athletes is undervalued. [9] sambo athletes benefit from physical activity by feeling better and enhancing their mental health. [10] the sambo athlete’s life satisfaction (swls) increases as the athlete engages in physical activity. since cricketers' mental health has received little attention, this is a gap that needs to be explored further. internal structures of sports organisations may emphasise mental toughness as critical for athletes, but they may fail to establish spaces where elite athletes can talk about their personal mental health difficulties to foster an open dialogue about the focal issue. [2] studies on athletes' mental health (and their symptoms) could lead to new ways to assist athletes who have been suffering with mental health challenges. as a result of the limited studies conducted on mental health in cricket (which has been further highlighted by the covid19 pandemic), as well as the numerous accurate tools that are available for an athlete’s mental health, the objectives of this study are to: (i) investigate the prevalence of mental health symptoms (anxiety, depression, stress, physical and emotional exhaustion (pee), devaluation of sports practice (dsp), reduced background: mental health of cricket players has been a topic of debate for a considerable time across the globe. objectives: the purpose of this study was to investigate the prevalence of mental health symptoms among semiprofessional male cricket players experienced during covid19, as well as the relationship between age and the depression, anxiety, stress scale (dass-21) sub-scale. methods: mental health symptoms were assessed among cricket players (n = 90) using the following instruments, respectively: depression, anxiety, stress scale – 21 (dass – 21); athlete burnout questionnaire (abq) and satisfaction with life scale (swls). descriptive (means ± standard deviations) and inferential (spearman’s correlations) statistics were calculated using spss (ibm version 27.0) at a significance level of p < 0.05. results: the study reported that 5.6% (n = 5) of cricketers believed life was futile, and 10% (n = 9) thought they were useless most of the time. however, on the anxiety sub-scale, 27% (n = 24) of cricketers indicated low confidence. in addition, 23% (n = 21) of cricketers reported being stressed. spearman's correlations revealed a positive and significant association between the dass-21 sub-scales and that cricketers' dass-21 sub-scale symptoms are unrelated to age. conclusion: the study found that there were moderate levels of anxiety, a reduced sense of achievement and a neutral feeling towards satisfaction with life. reducing mental health symptoms would extend the playing careers of cricket players. de-stigmatising mental health may result in more robust and accurate self-reports of mental health illness among elite athletes, which can enable sustainable change. keywords: depression, anxiety, psychology, cricketers, covid-19 s afr j sports med 2023;35:1-6. doi: 10.17159/2078-516x/2023/v35i1a15058 mailto:shaz.malele.sm@gmail.com http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15058 https://orcid.org/0000-0001-9464-6854 https://orcid.org/0000-0002-3570-9779 original research sajsm vol. 35 no.1 2023 2 sense of accomplishment (rsa) and satisfaction with life (swls)) among semi-professional male cricket players experienced during covid-19; and (ii) investigate the relationship between age and depression, anxiety and stress, as well as how they affect one another. methods study design a cross-sectional survey design was employed in this research study. the study obtained ethical clearance from the faculty of health sciences research ethics committee (rec-11302021) at the university of johannesburg. setting the research was conducted across different leagues in the western cape of south africa, namely: western province (wp) premier league (ama 20), wp first division a (ama 20), wp first division c (ama 20) and wp second division. both the varsity college cricket club and the western province cricket club were assessed on the same cricket ground, as they share the same venue. wynberg, green point and milnerton cricket clubs were all tested at their respective grounds. the survey design was utilised to identify the prevalence of mental health symptoms among cricket players after the resumption of sporting events following an extensive lockdown (between september 2021 and may 2022) as a result of covid-19. participants the inclusion criteria were male semi-professional western cape cricket players (provincial b and university squads), with an age range from 18 to 35 years, who had no chronic injuries or mental health illnesses. the initial sample size that was required was 150 (confidence level of 95%, within ± 5% of the measured value). the final sample size obtained for the study was 90 cricket players. for definition purposes, a semiprofessional cricket player refers to a cricket player who plays for a first-class team but not for a professional county/state/franchise team. [11] outcome measures depression, anxiety, stress scale – 21 (dass–21) a total of seven items were included in each of the three dass-21 scales. these sub-scales were depression, anxiety and stress. the depression scale evaluates symptoms such as dysphoria, hopelessness, a low opinion of oneself, a lack of enthusiasm or participation, anhedonia and laziness. the anxiety scales include measures of autonomic arousal, skeletal muscle effects, situational anxiety and subjective feelings of anxiousness. the stress scale has an effect on the level of persistent non-specific arousal. the following are the recommended cut-off scores for traditional severity labels: normal, moderate and severe. [12] the recommended cut-off scores for conventional severity labels (normal, moderate, severe) and scores on the dass-21 sub-scales will need to be multiplied by 2 to calculate the final score. athlete burnout questionnaire (abq) the abq is a 15-item scale that measures the level of athlete exhaustion. in the questionnaire for athletes with burnout [13], the condition was characterised by a combination of physical and emotional exhaustion (pee), devaluation of sports practice (dsp) and reduced sense of accomplishment (rsa). cricket players ranked the frequency of their experience on a five-point likert scale with 1 = almost never, 2 = seldom, 3 = occasionally, 4 = frequently and 5 = very constantly. raedeke and smith reported internal consistency estimates of 0.91 for emotional/physical exhaustion, 0.85 for impaired sense of accomplishment, and 0.90 for devaluation. [13] the grading method is based on the participant's average number of replies and ranges from 1 to 5. satisfaction with life scale (swls) the swls holistically assesses the athlete’s cognitive judgement of life. [14] the test comprises of five questions, which are answered on a scale from one to seven. the swls is an interval scale. scores from 1 to 1.86 indicate a considerable disagreement. categorisation of the cricket players’ responses followed the pimentel study [15] and were namely, strongly disagree (1.00 to 1.86), slightly disagree (1.86 to 2.71), somewhat disagree (2.71 to 3.57), neither agree nor disagree (3.57 to 4.43), somewhat agree (4.43 to 5.29), slightly agree (5.29 to 6.14) and strongly agree (6.14 to 7.00). these three questionnaires were used in similar studies: dass-21 [8], abq [16] and swls. [10] study procedure the recruitment process included sending coaches and club managers study information via digital and telephonic communication. the coaches and managers were approached first, as it was required to obtain permission to invite players if they would like to participate in the study. the players were subsequently invited and also informed about the research, as well as what was expected of them. informed consent was signed by the cricket players before completing the questionnaires. the study goals and any potential undesirable effects were described in detail. three mental health surveys were completed (between september 2021 and may 2022) by cricket players via an electronic link. the survey was designed in a way so that in order to proceed to the next question or section, the cricket player needed to complete the current question or section. in so doing, it eliminated any blank spaces or risk for non-responsiveness. participants were able to go back and change answers if needed. the player would be referred to a psychologist if they reported a severe rating according to the cut-off scores of the questionnaires. statistical analysis all of the survey questions were fixed responses, quantitative in nature. all results were gathered in real-time using an online survey platform (google forms), and exported to microsoft excel (2021) for analysis. for the first objective, descriptive statistics were employed to determine the prevalence of mental health symptoms. for the second objective, spearman's correlations were employed to determine the relationship original research 3 sajsm vol. 35 no.1 2023 between dass-21 and age. the statistical package for the social sciences (spss, ibm version 27.0) for windows was used to perform the statistical analysis on the data at a significance level of p < 0.05. results participants due to covid-19, the sample composition had to be altered based on the availability of cricketers and physical distancing. the average age of all participants was 24 ± 5 years. the selected sample consisted of five different teams: western province cricket club (18 %), green point cricket club (27%), milnerton cricket club (27%), wynberg cricket club (21%) and varsity college cricket club (8 %). most respondents were all-rounders (47 %), followed by bowlers (27 %), batters (18 %) and wicket-keepers (9 %). depression, anxiety, and stress indicators a non-parametric spearman’s correlation indicated that there was a strong, positive and significant correlation between stress and anxiety (r = 0.79; p = 0.000); stress and depression (r = 0.77; p = 0.000); and anxiety and depression (r = 0.75; p = 0.000). the survey revealed a trend that when one variable increases, so does the other. there were outliers reporting that some cricket players had elevated symptoms of either depression, anxiety or stress (figure 1). the numbers on the figure represent the players (e.g. 70). table 1 shows that symptoms were evident in each of the three dass-21 sub-scales: depression (4.37 ± 5.97) at a high normal level; anxiety (5.03 ± 6.37) at a moderate level; stress (6.82 ± 6.48) at a moderate level. there was no statistically significant difference between the positions of cricket players. according to spearman’s correlation, the relationship between dass-21 and age was weak, negative, and not significant as is evident in table 1. the relationship between age and anxiety (r = 0.168; p = 0.114); and age and depression (r = 0.052; p = 0.625) was not significant. a slight variation was found in the relationship between stress and age (r = 0.058; p = 0.585) which was weak, positive and not significant. physical and emotional exhaustion (pee), devaluation of sports practice (dsp), and reduced sense of accomplishment (rsa) table 1 shows the abq variables that were measured: pee (2.17 ± 1.03) with 10% of the participants feeling table 1. combined results from the mental health survey instruments of male semi-professional cricket players (n=90) dass–21 questionnaire responses item score depression 4.37 ± 5.97 anxiety 5.03 ± 6.37 stress 6.82 ± 6.48 the relationship between different sub-scales of dass–21 and age age stress anxiety depression age 1 stress 0.058 1 anxiety 0.168 0.79** 1 depression 0.052 0.77** 0.75** 1 athlete burnout questionnaire (abq) responses item score pee 2.17 ± 1.03 dsp 1.89 ± 1.06 rsa 2.99 ± 0.97 satisfaction with life scale (swls) questionnaire responses item score in most ways my life is close to my ideal 4.41 ± 1.39 the conditions of my life are excellent 4.77 ± 1.43 i am satisfied with my life 4.74 ± 1.75 so far, i have gotten the important things i want in life 4.51 ± 1.53 if i could live my life over, i would change almost nothing 3.89 ± 1.94 data are expressed as mean ± sd where applicable. ** correlation is significant at the 0.01 level (2-tailed). pee, physical and emotional exhaustion; dsp, devaluation of sports practice; rsa, reduced sense of achievement. scores: strongly agree = 7; agree = 6; slightly agree = 5; neither agree nor disagree = 4; slightly disagree = 3; disagree = 2; strongly disagree = 1. fig. 1. dass-21 based on sub-scales (depression, anxiety and stress) and how cricket players responded (n=90). box indicates the median and interquartile range; whiskers indicates the range. the circles and numbers on the figure represent the outliers (e.g. player 70). original research sajsm vol. 35 no.1 2023 4 physically worn out by the sport; and 20% exhausted by the mental and physical demands of cricket during the season; dsp (1.89 ± 1.06) was a rare occurrence; and participants sometimes experiencing a reduced sense of achievement (rsa; 2.99 ± 0.97). life satisfaction according to the study, 14% of participants were dissatisfied with their current life circumstances. overall, they neither agreed nor disagreed (4.46 ± 1.61) about being satisfied with life (table 1). discussion the objective of this study was to investigate the prevalence of mental health symptoms (anxiety, depression, stress, pee, dsp, rsa and swls) experienced among semi-professional male cricket players during covid-19. a secondary objective of this study was to investigate the relationship between age and the dass-21 sub-scale, as well as how they affect one another. the study found that mental health problems were less common among cricket players in lower divisions and that they were less likely to be prone to anxiety or depression. it has been found that 23% of cricketers had a difficult time winding down and that a variety of mental health difficulties, including mood disorders, suicide, drug and alcohol abuse and depression have been associated with cricket-related challenges. [1, 4] mental health research among athletes in south africa, only 5% of the national budget is allocated to mental health and only 50% of hospitals have the capability to deal with mental health conditions. [7] there is limited data on mental health illness among semi-professional athletes [10], as more studies relate to elite or professional athletes. studies have shown that male athletes tend to have low response rates when it comes to speaking out or filling out questionnaires. [4] the analysis from this study reported that all the dass-21 sub-scales were interrelated, and this is in line with ali and green. [17] results in this study support the use of dass-21 in a sports context, thereby, providing researchers with a reliable and valid mental health testing tool. mental health research among semi-professional cricket players limited research exists on the mental health profiles of cricket players and athletes as a whole. [1, 4] in the study, only 3.3% were unaware of changes in somatic anxiety. levels of anxiety were expected to be high due to the pandemic and uncertainty of what will happen next. [3] a study by tubic et al. [10] reported that semi-professional athletes were not equipped to handle high arousals of symptoms of anxiety. in contrast, elite athletes were reported to be better equipped to handle anxiety, as well as improvement of performance by managing their arousal. [17] the findings of the current study provides snapshots of how symptoms of anxiety, if not addressed, might result in an increase in the incidence rate of depression and stress symptoms. however, there was a difference when dass-21 was compared between recreational athletes and elite athletes. [17] to the best of our knowledge, this is the first study to investigate athlete burnout among semi-professional cricket players in south africa, as mental health profiling among cricket players is largely unknown. [1,3, 4] furthermore, the sub-scales had no correlation with age. pillay et al. [2] reported that one in every two athletes was sad, suffering from energy loss and a lack of drive to train. in contrast, this study found 40% of cricket players felt that they do not always reach their maximum athletic potential (i.e. in cricket). in addition, the rsa reported by hughes attributed to injuries and this might be a rare occurrence in the current study. [18] mood illnesses, suicidal thoughts, and substance misuse have all been linked to cricket-specific concerns. [1, 4] according to the swls in this study, cricket players reported a moderate level of life satisfaction. since there are no clinical cut-off scores for burnout measures, it is also still unknown how many athletes are suffering from this phenomena. [19] the impact of covid-19 on the mental health of cricket players training alone and lack of sport-specific training during lockdown led to an increase in mental health symptoms. [1] research has identified that covid-19 increased the phenomenon of mental health disorders, which was evident in an increase in mental fatigue and depression in football. [6] ali and green [17] found a strong correlation between dass–21 factors, age and ethnicity; however, the present study found contradictory results. during lockdown, players were required to be in bio-bubbles and no interaction with people outside of the bio-bubble. as a result, this led to rumination and depressive symptoms. [2] the current study highlights the effects of covid-19 on the player’s mental health as some experienced symptoms of depression. these results compliment the findings by pillay et al. [2] which depicted symptoms of depression being high during covid19. it was further reported by schuring that there was a link between unhappiness and a significantly elevated risk of distress, anxiety, and depression among cricket players. [20] it is, therefore, imperative for cricket clubs to be aware of depressive symptoms among cricket players and provide assistance when needed. future research directions for mental health in cricket (and sport in general) more research is needed to discover the root causes of athletes' discontent with sports so that targeted remedies can be developed. [5, 20] there are also limited studies investigating swls among semi-professional cricket players and the current study provides a snapshot of what transpired during covid19. future research studies should compare the mental health of male and female cricket players respectively to determine whether there are any relationships with their performance. lastly, research should also be conducted among larger sample groups and players with varied skill levels. limitations male cricket players, who are known to be less receptive to original research 5 sajsm vol. 35 no.1 2023 mental health questions, were the only participants. selfreported assessments may provide outcomes that are distorted or subjective. this study could not account for a variety of characteristics, such as the history of mental health difficulties and current treatment, or the direct impact of the covid-19 outbreak (i.e. bereavement, loss of income, etc.). the generalisability of the conclusions are constrained by the sample of this population, and larger samples are necessary to acquire a deeper understanding of semi-professional cricket players. due to possible selection bias, the recruited sample may not be typical of semi-professional cricketers in cape town, south africa, and external validity may be limited. recommendations and future studies a key recommendation from this study is that teams of cricket players should do weekly mental health monitoring to determine whether players require time with a psychologist. the cricket community should consider employing a mental health consultant who focuses entirely on the psychological aspects of players, since this would result in specialised sessions for cricketers and enhanced performance. this may also be conducted in collaboration with biokineticists, physiotherapists, and other allied health specialists in order to assist the cricketer holistically. providing a space where any player may speak openly about their mental health is also paramount. conclusion the current study provided a snapshot of the prevalence of mental health symptoms experienced by cricket players during covid-19. the study found that there were moderate levels of anxiety, a reduced sense of achievement and a neutral feeling towards satisfaction with life. reducing burnout, mental health symptoms and life dissatisfaction would extend the playing careers of cricket players. destigmatising mental health may result in more robust and accurate self-reports of mental health illnesses among elite athletes, which can enable sustainable change. existing studies of the psychological aspects among cricket players cannot be compared to post-lockdown situations, as there are currently no comparative or baseline data. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: gratitude must be given to the coaches, managers and conditioning coaches for referring the researchers to eligible cricket 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distance runners. int j sports med 1989; 10: 97-100. introduction the comrades marathon is a 90 km ultramarathon race, run annually between durban and pietermaritzburg, south africa. however, the start and finish of the race alternate each year, and the race is therefore run in different directions. in the ‘up’ run the race starts at sea level in durban, and runners ascend to the finish in pietermaritzburg, at 650 m above sea level. the highest point in the race is 870 m above sea level. in the ‘down’ run, the race starts in pietermaritzburg, and runners descend to the finish in durban.11 marathon and ultramarathon races impose severe physiological stresses on runners.6,17 previous studies on runners of the 90 km comrades marathon have provided information regarding changes in ecg activity,13 serum enzyme activities, fluid balance,12 renal function,19 factors explaining the development of hyponatraemic encephalopathy,18 and the decrement in muscle power associated with muscle damage.6 it is well documented that muscle damage is a common occurrence associated with distance running.6,17 exercise-induced muscle damage is characterised by a disruption of the sarcolemma,2 sarcotubular system,2,4 contractile components of the myofibril, the extracellular matrix and the cytoskeleton.15 distance running is original research article differences in muscle pain and plasma creatine kinase activity after ‘up’ and ‘down’ comrades marathons abstract objective. the aim of this study was to compare the acute changes in muscle pain and plasma creatine kinase (ck) activity following the ‘up’ and ‘down’ comrades marathon. design. this was a quasi-experimental design. eleven male runners (39.7±9.3 years) completed the ‘up’ comrades marathon, and 11 male runners (41.0±8.4 years) completed the ‘down’ comrades marathon the following year. maximum oxygen consumption and peak treadmill running speed were measured 2 weeks before the race. daily measurements of muscle pain and plasma creatine kinase (ck) activity were recorded 1 day before, and for 7 days after the race. results. muscle pain remained significantly elevated for up to 7 days after the comrades marathon, compared with pre-race values (p<0.0009). the pain scores following the ‘down’ run were significantly higher than the pain scores following the ‘up’ run for at least 7 days after the race (p<0.004). plasma ck activity recorrespondence: theresa burgess division of physiotherapy school of health and rehabilitation sciences f45 old main building groote schuur hospital anzio road 7725 observatory south africa tel: 27 21 406-6171 fax: 021 406-6323 e-mail: theresa.burgess@uct.ac.za theresa l burgess1, 2 (bsc (physio), bsc (med)(hons) (exercise science)) michael i lambert1 (phd) 1 mrc/uct research unit for exercise science and sports medicine, department of human biology, university of cape town, sports science institute of south africa 2 division of physiotherapy, school of health and rehabilitation sciences, university of cape town mained significantly elevated for up to 5 days after the comrades marathon, compared with pre-race values (p<0.007). plasma ck activity following the ‘down’ run was significantly higher than the plasma ck activity following the ‘up’ run for 5 days after the race (p<0.04). a high degree of intra-individual variability in plasma ck activity was observed. conclusions. the ‘down’ comrades marathon causes significantly more muscle pain and plasma ck activity compared with the ‘up’ comrades marathon. further studies are required to accurately define the regeneration of muscle following the comrades marathon. 54 sajsm vol 20 no. 2 2008 pg49-58.indd 54 8/11/08 8:52:51 am also associated with impaired muscle function,6,23,24 and delayedonset muscle soreness (doms).22 previous studies have shown that muscle pain associated with doms usually dissipates within 96 hours after exercise,3,5 but may persist for up to 10 days after exercise.8 plasma creatine kinase (ck) activity is one of the most commonly used indicators of muscle damage.22 creatine kinase is released into the blood when the cell membrane is damaged, or when there is an alteration in cell membrane permeability.1 the extent and duration of the plasma ck response to exercise varies according to the type of exercise.7 plasma ck activity peaks within 24 48 hours after a marathon.22,27 anecdotally, runners report a greater degree of muscle pain and a prolonged recovery period following the ‘down’ run, compared with the ‘up’ run. this is not unexpected, as during the ‘down’ run there will be more eccentric strain on the muscles, which is known to be a risk factor for causing muscle damage.9 however, the anecdotal observations have not been confirmed experimentally and the physiological responses associated with doms following the comrades marathon have not been established. accordingly, the aim of this study was to compare acute changes in muscle pain and plasma creatine kinase activity following the ‘up’ and ‘down’ comrades marathon. methods subjects and study design twenty-two healthy male runners who participated in the comrades marathon were selected for the study, which had a quasi-experimental design. the study was granted ethical clearance by the ethics and research committee of the faculty of health sciences, university of cape town. subjects gave written consent after being informed about the demands of the study. the subjects completed a questionnaire to determine their age, training history, medical and surgical history, and any past or present injuries to the lower limbs. the study was conducted over a 2-year period. eleven subjects participated in the ‘up’ comrades marathon, and 11 subjects participated in the ‘down’ comrades marathon. one subject participated in both the ‘up’ and ‘down’ races. the subjects were requested to avoid any medication, and strenuous training and racing, other than the comrades marathon, for the duration of the study (± 20 days). testing occurred at a similar time (to within 1 hour) for each subject for the duration of the study. preliminary testing preliminary testing was conducted on all subjects 2 weeks before the comrades marathon. all subjects had their body composition assessed. body fat was represented as the sum of seven skinfolds (biceps, triceps, subscapular, supra-iliac, calf, thigh and abdomen), as described by ross and marfell-jones,29 and also as a percentage of body mass.14 a maximal treadmill test was performed to determine maximum oxygen consumption (vo2max), peak treadmill running speed (ptrs), and maximum heart rate (hrmax). the maximal test was performed on a treadmill (quinton instruments, seattle, wa, usa) with the elevation set at 1%, in order to reproduce the energetic cost of running outdoors on a flat surface.20 the subjects warmed up before the maximal test. the timing and intensity of the warm-up was specific for each subject, and was maintained for the duration the study. the test began with the treadmill speed set to 10 km.h-1. this speed was maintained for 2 minutes, after which it was increased by 0.5 km.h-1 every 30 seconds until the subjects were unable to maintain the speed of the treadmill. during the maximal test, subjects wore a mouthpiece and a nose clip. the expired air passed through an online computer system attached to an oxycon alpha automated gas analyser (jaeger/ mijnhardt, groningen, the netherlands) for the determination of oxygen consumption (vo2) and respiratory exchange ratio (rer). before each test, the gas analyser was calibrated with a 3 l hans rudolph 5530 l syringe and an online co2:n2 gas mixture of known composition. heart rate was recorded (polar vantage xl, polar electro, kempele, finland) at 5-second intervals. vo2max was defined as the vo2 value that coincided with volitional fatigue. ptrs was defined as the highest speed that the runner could maintain for a complete 30-second increment prior to fatigue. hrmax was recorded as the highest heart rate during the last 30 seconds of the treadmill test. muscle pain muscle pain was measured daily for 1 day before, and for 7 days after the comrades marathon. muscle pain was measured subjectively, where subjects rated lower limb pain according to a ‘rating of perceived pain’ on a scale of 0 to 10, where 0 represents ‘no pain’, and 10 represents ‘maximal pain’. this method of measurement of muscle pain has previously been shown to be highly correlated with objective pain measures.30 plasma creatine kinase activity daily blood samples, for the analysis of plasma creatine kinase (ck) activity, were collected for 1 day before, and for 7 days after the comrades marathon. a 5 ml blood sample was taken from the subject’s antecubital vein for the analysis of plasma ck activity. the blood samples were collected into pre-chilled tubes containing lithium heparin and were kept on ice for a maximum of 3 hours until centrifugation. blood samples were centrifuged at 2000 x g for 10 minutes at 4°c, and plasma was stored at -20°c until the analysis of plasma ck activity. plasma ck activity was measured by spectrophotometric (beckman instruments, fullerton, ca) enzymatic assays (ck-nac activated, boehringer mannheim automated analysis for bm/hitachi systems 704, meylan, france). comrades marathon the comrades marathon race profiles for the 86.55 km ‘up’ run, and the 89.9 km ‘down’ run are shown in fig. 1(a) and 1(b) respectively.11 comrades race speed was expressed as a percentage of each subject’s personal best 10 km speed. statistical analyses statistical analyses were performed using statistica software (statsoft, inc. (2007) statistica (data analysis software system), version 8.0. www.statsoft.com). differences in descriptive variables between groups were assessed using an independent t-test. a mannwhitney u test was used to assess differences in the pain scores on each day between groups. a friedman’s anova and kendall’s concordance were used to assess differences in the pain scores within groups over time. as the plasma ck activity data had unequal variance, the logarithm of each value was determined, and these values were then used in an analysis of variance (anova) with repeated measures to determine the significance for the two main effects of group and time, and the interaction (group x time). a tukey’s post hoc test was used to identify specific differences. all data are presented as the mean ± standard deviation. statistical significance was accepted as p<0.05. results the descriptive characteristics of subjects are shown in table i, and the training and racing history of subjects are shown in table ii. there were no significant differences between groups for any sajsm vol 20 no. 2 2008 55 pg49-58.indd 55 8/11/08 8:52:51 am of the descriptive variables. there were significant differences in the 10 km personal best times (p<0.006) and the 42 km personal best times (p<0.04) between groups, with the ‘down’ group being significantly faster over both distances. however, when the comrades race speeds were expressed as a percentage of the subjects’ 10 km personal best speed there were no differences between groups. there were no significant differences between groups for any of the other training history variables. the subjects in the ‘up’ group completed the 86.55 km race in 606.6±39.2 minutes. the average intensity (% hrmax) during the race was 83.5±4.0%. the subjects in the ‘down’ group completed the 89.9 km race in 566.4±64.5 minutes. the average intensity (% hrmax) during the race was 79.2±2.2%. there were no differences between groups in race time or intensity. muscle pain the muscle pain of subjects in the ‘down’ and ‘up’ groups is shown in fig. 2. the subjective pain scores (arbitrary units) were significantly higher in the ‘down’ group on days 1 (6.6±2.0 v. 4.2±0.8; p<0.004), 2 (6.2±1.9 v. 2.8± .1; p< 0.0003), 3 (5.3±1.4 v. 2.1±1.4; p<0.0004), 4 (4.3±1.2 v. 1.3±1.3; p<0.0005), 5 (3.6±1.3 v. 0.7±0.9; p<0.0003), 6 (3.0±1.3 v. 0.6±0.9; p<0.0008), and 7 (2.6±1.1 v. 0.4±0.7; p<0.0004) after the comrades marathon, compared with ‘up’ group values on the same days. although muscle pain in the ‘up’ group had returned to pre-race values by day 7 after the comrades marathon, muscle pain in the ‘down’ group remained elevated compared with pre-race values (2.6±1.1 v. 0.0; p<0.0009). plasma ck activity there was a significant interaction between groups over time for plasma ck activity (f(7, 140) = 3.13; p<0.004) (fig. 3). plasma ck activity was significantly higher in the ‘down’ group on days 1, 2, 3, 4, and 5, compared with pre-race values (p<0.007). plasma ck activity was also significantly higher in the ‘up’ group on days 1, 2, and 3, compared with pre-race values (p<0.006). plasma ck activity had therefore returned to pre-race values by day 4 in the ‘up’ group, and day 6 in the ‘down’ group. other differences between days and groups are shown in fig. 3. discussion the comrades marathon induced muscle pain in both groups consistent with delayed-onset muscle soreness (doms).7 the onset of muscle pain in both groups occurred within the first 24 hours following the race, which is consistent with other studies investigating the onset of doms resulting from exercise-induced muscle damage.8,25 in the ‘up’ group, subjective pain had returned to pre-race values by day 5 after the race. however, in the ‘down’ group, muscle pain remained elevated at 7 days after the race. studies have shown that muscle pain associated with doms usually dissipates within 96 hours after exercise,3,5,10 but in some cases may persist for up to 10 days, particularly following high-force eccentric exercise protocols involving maximal contraction of the elbow flexors.8 unfortunately data were not collected beyond 7 days, therefore the exact time course of recovery of muscle pain following the ‘down’ run is unclear. further, although the time course of recovery of muscle pain is similar following different types of exercise-induced muscle damage, the extent of soreness may vary. for example, high-force eccentric exercise protocols involving maximal contraction of the elbow flexors are associated with higher subjective pain scores compared with protocols involving downhill running.7 this is the first study to demonstrate a difference in subjective pain scores following the ‘up’ compared with the ‘down’ comrades marathons. it is logical to assume that the difference in pain scores between the ‘down’ and ‘up’ groups is related to the increased amount of downhill running during the ‘down’ comrades marathon. downhill running is associated with a greater magnitude of eccentric (musclelengthening) action compared with level running, and therefore a greater degree of muscle damage.3 the underlying mechanisms for the pain associated with doms are not well understood. it has been suggested that soreness may result from swelling and pressure in the muscle.31 although biopsy studies have demonstrated increases in muscle fibre area and intramuscular pressure,16 discrepancies between the timing of peak muscle soreness and oedema have been identified.26 it has also been suggested that chemicals such as histamines, prostaglandins, and bradykinins may be associated with the development of muscle soreness following exercise-induced muscle damage. it is theorised that these substances are released when the muscle is damaged, resulting in activation of type iii and iv nerve afferents, leading to the sensation of pain.28 however, there is no direct evidence to support this theory.7 in addition, although subjective pain remained significantly elevated for up to 7 days after the comrades marathon, this does not necessarily reflect the magnitude of muscle damage5 or longterm changes in neuromuscular function. for example, it is known that neuromuscular function is disturbed for at least 11 days after the comrades marathon.6 furthermore, signs of regeneration are still present in the muscle of runners 12 weeks after a standard marathon, despite the absence of pain.32 there is a complex interaction between exercise-induced muscle damage and fatigue due to prolonged exercise. this is characterised by alterations in neuromuscular function including an increase in contact time, decreases in stretch reflex sensitivity, preactivation, and elastic energy potential, and changes in stiffness regulation.21 these factors are all affected by absolute running speed. it is acknowledged that a potential limitation of this study is the difference in 10 km personal best time between the ‘up’ and ‘down’ groups. due to the inherent differences in distance and profile between the ‘up’ and ‘down’ runs, race speed was expressed as a percentage of the individual 10 km personal best time. although no significant differences were observed in race 0 10 20 30 40 50 60 70 80 90 0 150 300 450 600 750 0 10 20 30 40 50 60 70 80 90 0 150 300 450 600 750 distance al ti tu d e (m ) (b) (a) race profiles fig. 1. race profiles of the (a) ’up’ and (b) ‘down’ comrades marathon. fig. 1. race profiles of the (a) ’up’ and (b) ‘down’ comrades marathon. 56 sajsm vol 20 no. 2 2008 pg49-58.indd 56 8/11/08 8:52:53 am time (minutes), intensity (% hrmax), and speed (% 10 km time), it is recognised that expression of race speed as a percentage of the 10 km personal best time may mask differences in the rate of stretchshortening cycle exercise during the ultramarathon race. although it may be argued that differences in absolute running speed are associated with differences in loading forces, the differences in this study were subtle and arguably not a major factor associated with the development of the muscle damage. plasma creatine kinase (ck) activity is a commonly used indicator of muscle damage.22 plasma ck activity was significantly higher after the ‘down’ run, compared with the ‘up’ run, and remained significantly elevated for 5 days compared with pre-race values in the ‘down’ group, whereas in the ‘up’ group, values had returned to prerace values by day 4 after the comrades marathon. these findings are consistent with other studies that also reflect a rapid increase in ck activity from 24 hours after a marathon.22,27 kryöläinen et al.22 reported peak plasma ck activity of 1147±520 u.l-1 2 days after a marathon. conversely, after high-force eccentric exercise protocols, for example, maximal contraction of the elbow flexors, the table i. descriptive characteristics of subjects in the ‘up’ (n=11) and ‘down’ (n=11) groups (mean ± sd) variable up down age (years) 39.7±9.3 41.0 ±8.4 body mass (kg) 74.9± 4.6 71.8±11.6 height (cm) 177.5±7.6 177.2±6.2 sum of skinfolds (mm) 95.9±36.0 74.9±20.9 body fat (%) 21.6±5.1 19.6±4.4 maximum heart rate (b.min -1 ) 177±11 180±15 vo2max (mlo2.kg -1 .min -1 ) 54.7±7.2 57.8±5.5 peak treadmill running 16.7±1.5 17.6±1.7 speed (ptrs) (km.h -1 ) table ii. training and racing history of subjects in the up (n=11) and down (n=11) groups (mean ± sd) variable up down total years running 7.6±7.6 10.5±7.2 pre-competition training 70.5±10.6 72.7±15.6 distance (km.wk -1 ) average training 56.6±6.5 55.5±11.7 distance (km.wk -1 ) * number of standard 30±30 37±26 marathons (42 km) personal best 10 km time 43.1±3.0 37.9±3.3 (min) † personal best 42 km time 209.2±15.8 189.7±23.1 (min) ‡ race speed (%) § 60.1±3.5 60.7±5.8 *average training distance in the 6 months preceding the race. significant differences: † personal best 10 km time: up v. down (p<0.006) ‡ personal best 42 km time: up v. down (p<0.04) § comrades speed expressed as a percentage of 10 km personal best speed. -1 0 1 2 3 4 5 6 7 0.0 2.5 5.0 7.5 10.0 **** **** ** **** up down days p ai n sc o re (a rb it ra ry u n it s) muscle pain fig. 2. muscle pain (arbitrary units) of subjects in the ‘up’ (--) (n=11) and ‘down’ (-o-) (n=11) groups. tests were conducted 1 day before the race, and daily for 7 days after the race. data are expressed as mean ± sd. significant differences: ** ‘down’ days 1, 2, 3, 4, 5, 6, and 7 v. ‘up’ days 1, 2, 3, 4, 5, 6, and 7 respectively (p<0.004 fig. 2. muscle pain (arbitrary units) of subjects in the ‘up’ (-•-) (n=11) and ‘down’ (-o-) (n=11) groups. tests were conducted 1 day before the race, and daily for 7 days after the race. data are expressed as mean ± sd. significant differences: ** ‘down’ days 1, 2, 3, 4, 5, 6, and 7 v. ‘up’ days 1, 2, 3, 4, 5, 6, and 7 respectively (p<0.004). -1 0 1 2 3 4 5 6 7 0.0 2.5 5.0 7.5 * ** # **** ** ** φφφφ φφφφ φφφφ φφφφ φφφφφφφφ φφφφ up down days p la sm a c k ac ti vi ty (u .i -1 ) plasma creatine kinase fig. 3. plasma creatine kinase activity (u.l-1) of subjects in the ‘down’ (-•-) (n=11) and ‘up’ (-o-) (=11) groups. tests were conducted 1 day before the race, and daily for 7 days after the race. data are expressed as mean ± sd. significant differences: ** ‘down’ day 1 v. ‘down’ days -1, 1, 3, 4, 5, 6, 7 (p<0.00003), and 2 (p<0.03) ** ‘down’ day 2 v. ‘down’ days -1, 4, 5, 6, and 7 (p<0.00003) ** ‘down’ day 3 v. ‘down’ days -1, 5, 6, and 7 (p<0.00004) ** ‘down’ day 4 v. ‘down’ days -1, 7 (p<0.00006), and 6 (p<0.04) ** ‘down’ day 5 v. ‘down’ day -1 (p<0.007) ** ‘up’ days 1 and 2 v. ‘up’ days -1, 3, 4, 5, 6, and 7 (p<0.00003) ** ‘up’ day 3 v. ‘up’ days -1, 6, and 7 (p<0.006) f ‘down’ day 1 v. ‘up’ days -1, 1, 2, 3, 4, 5, 6, and 7 (p<0.02) f ‘down’ days 2 and 3 v. ‘up’ days -1, 3, 4, 5, 6, and 7 (p<0.003) f ‘down’ day 4 v. up days -1, 4, 5, 6, and 7 (p<0.04) f ‘down’ day 5 v. ‘up’ days -1, 6, and 7 (p<0.02) f ‘down’ day 6 v. ‘up’ day 1 (p<0.02) f ‘down’ day 7 v. ‘up’ days 1 and 2 (p<0.007) # interaction of group x time (p<0.004) sajsm vol 20 no. 2 2008 57 pg49-58.indd 57 8/11/08 8:52:55 am increase in ck activity does not begin until approximately 48 hours after the exercise, with peak ck activity occurring only between 4 6 days following the exercise.7 the differences in plasma ck activity following downhill running and high-force eccentric exercise protocols is well-documented;7 however, the underlying mechanism for the different responses is unclear. this is the first study to demonstrate a difference in the ck response to ultra-endurance exercise. it may be hypothesised that the difference in ck activity between the ‘down’ and ‘up’ groups is related to the increased amount of downhill running during the ‘down’ comrades marathon compared to the ‘up’ comrades marathon, and therefore the greater magnitude of eccentric (muscle-lengthening) action during the ‘down’ run. studies have shown a dissociation between ck activity and the extent of exercise-induced muscle damage,26,30 therefore one should interpret the magnitude of ck activity as a direct marker of muscle damage with caution. however in this study, as pain was also elevated it is logical to conclude that the ‘down’ group did indeed have more muscle damage.7 there was also a large degree of intra-subject variability in plasma ck activity, particularly in the ‘down’ group at days 1 and 2 after the comrades marathon. this individual variation in ck activity may be associated with differences in the rate of ck clearance by muscle and the reticuloendothelial system,8 and not related to physical activity, gender, or muscle mass. 7 unfortunately the design of this study cannot provide an explanation for the large degree of intra-individual variation in ck activity. further studies are needed to investigate this finding. in conclusion, the ‘down’ comrades marathon causes more muscle pain and plasma ck activity compared with the ‘up’ comrades marathon. subjective pain scores remained elevated for at least 7 days after the ‘down’ race, but only for 4 days after the ‘up’ race. further studies are required to accurately define the regeneration of muscle following the comrades marathon after the symptoms of damage have disappeared. acknowledgements the first author (tb) would like to thank the university of cape town for financial support from the urc emerging researcher fund. the comrades marathon organising committee is also thanked for financial support for the study. references 1. armstrong rb. muscle damage and endurance events. sports med 1986; 3: 370-81. 2. armstrong rb. initial events in exercise-induced muscular injury. med sci sports exerc 1990; 22: 429-35. 3. braun wa, dutto dj. the effects of a single bout of downhill running and ensuing delayed onset of muscle soreness on running economy performed 48 h later. eur j appl physiol 2003; 90: 29-34. 4. byrd sk. alterations in the sarcoplasmic reticulum: a possible link to exercise-induced muscle damage. med sci sports exerc 1992; 24: 531-6. 5. byrne c, twist c, eston r. neuromuscular function after exercise-induced muscle damage. theoretical and applied implication. sports med 2004; 34: 49-69. 6. chambers c, noakes td, lambert ev, lambert mi. time course of recovery of vertical jump height and heart rate versus running speed after a 90-km foot race. j sports sci 1998; 16: 645-51. 7. clarkson pm, hubal mj. exercise-induced muscle damage in humans. am j phys med rehabil 2002; 81: s52-s69. 8. clarkson pm, nosaka k, braun b. muscle function after exercise-induced muscle damage and rapid adaptation. med sci sports exerc 1992; 24: 512-20. 9. clarkson pm, tremblay i. exercise-induced muscle damage, repair, and adaptation in humans. j appl physiol 1988; 65: 1-6. 10. cleak mj, eston rg. delayed-onset muscle soreness: mechanisms and management. j sports sci 1992; 10: 325-41. 11. comrades marathon association. comrades. www. comrades. co.za 2008. 12. dancaster cp, whereat sj. fluid and electrolyte balance during the comrades marathon. s afr med j 1971; 45: 147-50. 13. dancaster cp, whereat sj. renal function in marathon runners. s afr med j 1971; 45: 547-51. 14. durnin jvga, womersley j. body fat assessed from the total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. br j nutr 1974; 32: 77-97. 15. friden j, lieber rl. structural and mechanical basis of exercise-induced muscle injury. med sci sports exerc 1992; 24: 521-30. 16. friden j, sfakianos pn, hargens ar. residular muscular swelling after repetitive eccentric contractions. j orthop res 1988; 6: 493-8. 17. hikida rs, staron rs, hagerman fc, sherman wm, costill dl. muscle fiber necrosis associated with human marathon runners. j neurol sci 1983; 59: 185-203. 18. irving ra, buck rh, godlonton j, noakes td. evaluation of renal function and fluid homeostasis during recovery from exercise induced hyponatremia. j appl physiol 1991; 70: 342-8. 19. irving ra, noakes td, burger sc, myburgh kh, querido d, van zyl smit r. plasma volume and renal function during and after ultramarathon running. med sci sports exerc 1990; 22: 581-7. 20. jones am, doust jh. a 1% treadmill grade most accurately reflects the energetic cost of outdoor running. j sports sci 1996; 14: 321-7. 21. komi pv. stretch-shortening cycle exercise: a powerful model to study normal and fatigued muscle. j biomech 2000; 33: 1197-206. 22. kryöläinen h, pullinen t, candau r, avela j, huttunen p, komi pv. effects of marathon running on running economy and kinematics. eur j appl physiol 2000; 82: 297-304. 23. morgan dl, allen dg. early events in stretch-induced muscle damage. j appl physiol 1999; 87: 2007-15. 24. morgan dw, craib m. physiological aspects of running economy. med sci sports exerc 1992; 24: 456-1. 25. nosaka k, clarkson pm. muscle damage following repeated bouts of high force eccentric exercise. med sci sports exerc 1995; 27: 1263-9. 26. nosaka k, clarkson pm. variability in serum creatine kinase response after eccentric exercise of the elbow flexors. int j sports med 1996; 17: 120-7. 27. nuviala rj, roda l, lapieza mg, boned b, giner a. serum enzyme activities at rest and after a marathon race. j sports med phys fitness 1992; 32: 180-6. 28. o’connor pj, cook db. exercise and pain: the neurobiology, measurement, and laboratory study of pain in relation to exercise in humans. exerc sports sci rev 1999; 27: 119-66. 29. ross wd, marfell-jones mj. kinanthropometry. in: macdougall jd, wegner ha, green hj eds. physiological testing of the high-performance athlete. champaign, il, usa: human kinetics books, 1991. 30. semark a, noakes td, st clair gibson a, lambert mi. the effect of a prophylactic dose of flurbiprofen on muscle damage, soreness and sprinting performance in trained subjects. j sports sci 1999; 17: 197-203. 31. smith ll. acute inflammation: the underlying mechanism in muscle soreness? med sci sports exerc 1991; 23: 542-51. 32. warhol mj, siegel aj, evans wj, silverman lm. skeletal muscle injury and repair in marathon runners after competition. am j pathol 1985; 118: 331-9. 58 sajsm vol 20 no. 2 2008 pg49-58.indd 58 8/11/08 8:52:56 am sportsmed_june04 28 sports medicine vol 16 no.2 2004 introduction super-compensation is the main principle in physical training aimed at improving performance. a breakdown process in skeletal muscle is followed by a recovery process, resulting in adaptation and possibly increased exercise performance.32 exercise has a profound effect on skeletal muscle metabolism resulting in net muscle protein breakdown and glycogen depletion during exercise, followed by net protein synthesis and, depending on nutrient availability, glycogen storage post-exercise. the recovery process (muscle regeneration, glycogen and fluid restoration) is regarded as critical to successful training and adaptation, and nutrition has been identified as a major contributor in this process.35 increasing the rate of recovery post-exercise, or decreasing the rate of catabolism during exercise, could lead to speedy and effective recovery between training sessions. an enhanced recovery process is of particular importance to athletes who do more than one training session per day, and/or engage in strenuous multi-day training or competition schedules. macronutrients, specifically carbohydrate (cho) and protein, have been identified as crucial dietary components in enhancing the recovery process. by regulating the timing, amount and type of these nutrients ingested, anabolism post-exercise can be reached at an earlier stage compared with unregulated ingestion of these nutrients.24,25,49 this article consists of two parts, focusing on the effect of the macronutrients, individually and in combination, on glycogen storage (part i) and skeletal muscle repair (part ii) post-exercise. in both parts possible mechanisms will be identified and conclusions drawn. at the end of part ii one combined set of dietary recommendations for optimal recovreview article dietary macronutrient recommendations for optimal recovery post-exercise: part i h h wright (msc dietetics, phd nutrition)1 a claassen (bsc (hons) dietetics, bsc (med) (hons) exercise science)2 j davidson (dsc)3 1potchefstroom institute of nutrition, faculty of health sciences, northwest university, south africa 2uct/mrc research unit for exercise science and sports medicine, faculty of health sciences, university of cape town, south africa 3college of education and health sciences, bradley university, peoria, illinois, usa correspondence: h wright school of physiology, nutrition and consumer science north-west university private bag x6001 potchefstroom, 2531 tel: 018-299 2482 fax: 018-299 2464 e-mail: vgehhw@puk.ac.za abstract prolonged, strenuous exercise results in muscle glycogen depletion. recovery of these stores prior to the next training session or competition is crucial to optimise exercise performance. nutrition plays an important role during the post-exercise recovery period when processes such as muscle regeneration, glycogen and fluid restoration take place. by manipulating the timing, type and frequency of food intake the rate of recovery can be enhanced, which is of particular importance to athletes performing multiple training or competition sessions within a day, or on a dayto-day basis and recovery time is limited. restoration of muscle glycogen stores is especially important for athletes participating in prolonged exercise, since depleted glycogen stores are associated with impaired exercise performance. key factors affecting muscle glycogen storage are carbohydrate (cho) availability and an increased insulin concentration, both of which are influenced by amount and timing of cho intake, type of cho ingested, the ratio of cho to protein ingested, and the fat content of a food item or meal. to maximise the rate of muscle glycogen restoration during a short (< 6-hour) recovery period, 1 1.5 g moderate to high glycaemic index cho/kg body weight (bw) immediately post-exercise, followed by 0.8 1.5 g moderate to high glycaemic index cho/kg bw/hour (divided in smaller doses every 15 60 minutes) for 3 4 hours should be ingested. with a longer recovery period (≥ 6 hours) muscle glycogen storage is independent of type of cho ingested but a total of 7 10 g cho/kg bw should be taken in within a 24-hour period. combining protein with an adequate amount of cho (> 1 g/kg bw/hour) has no added advantage in terms of enhanced rate of glycogen storage, but can be of practical importance. additionally, this combination may be beneficial since cho and amino acid availability are important for muscle repair during the recovery period, as will be discussed in detail in part ii of this article. sports medicine vol 16 no.2 2004 29 ery of glycogen stores and skeletal muscle repair post-exercise is provided. glycogen storage glycogen, specifically muscle glycogen, is the predominant fuel source during exercise of moderate to high intensity (> 60% maximal oxygen uptake (vo2max). 45 during prolonged exercise, glycogen stores become depleted and blood glucose concentrations may start to decline, a situation which is often associated with a decrease in cho oxidation and impaired exercise performance.4;5;13;22 hence, efficient recovery of glycogen stores (in the liver and muscles) in the postexercise period has been identified as an important strategy to enhance subsequent exercise performance. restoration of these stores is dependent on glucose supply originating from dietary cho. restoration of liver glycogen stores is important for optimal maintenance of blood glucose concentrations, which serve as the predominant fuel source to the brain and central nervous system,38 as well as to the working muscles when muscle glycogen becomes depleted.4,19,55 however, restoration of muscle glycogen in the post-exercise period takes precedence over liver glycogen restoration, which, even in the absence of dietary cho supply, can occur at a low rate (~ 1 2 mmol/kg wet weight (ww)/hour), with some of the substrate being provided through gluconeogenesis.3 therefore, part i of this article focuses on aspects increasing the rate of muscle glycogen recovery specifically. dietary factors affecting muscle glycogen storage the key dietary factors that can enhance the rate of muscle glycogen synthesis include: increased cho (glucose) availability;17 an elevated insulin concentration;21 and the combination of cho and protein or amino acids to increase the insulinotrophic effect and provide substrate for glycogen and muscle protein regeneration.26 non-dietary factors that may augment the rate of glycogen synthesis (for detailed review see jentjens and jeukendrup30) include glycogen synthase activity (increased by both muscle contraction and insulin); glucose transport protein-4 (glut-4) availability and translocation within the muscle cell (increased by muscle contraction and insulin concentrations); training status (training increases insulin signalling and sensitivity, glut-4 content, and blood flow); degree of muscle glycogen depletion (glycogen depletion may increase glut-4 availability and glycogen synthase activity, thereby increasing the rate of muscle glycogen restoration).30 cho availability: amount and timing of cho ingestion it has been established that post-exercise glycogen synthesis takes place in a biphasic manner, with a rapid, insulinindependent phase lasting between 30 and 60 minutes, and a slow, insulin-dependent phase, which, depending on cho availability and high insulin levels, can persist for several hours.42,43 the rapid phase only occurs when post-exercise muscle glycogen concentrations are below 30 35 mmol/kg ww43 and cho is provided immediately post-exercise.28 hence, of the abovementioned dietary factors, cho availability remains the key factor affecting both phases of postexercise glycogen synthesis and rate of recovery. several studies have demonstrated very low rates of muscle glycogen synthesis when no cho was ingested or when cho intake was delayed (> 2 hours) compared with immediate cho ingestion post-exercise.28,48,51 the mechanism behind an increased rate of glycogen synthesis with immediate post-exercise cho ingestion might be related to an increased glycogen synthase activity (for review see nielsen and richter37) and glut-4 availability immediately following exercise.36 however, in the absence of cho ingestion, these exercise-induced increases in glycogen synthase and glut4 availability (and hence the potential for glucose transport) may decline rapidly.12,23 when considering the ideal amount of cho to be ingested, blom et al.3 demonstrated an increase in muscle glycogen synthesis rate of ~ 150% when post-exercise cho intake was increased from 0.18 to 0.35 g/kg body weight (bw)/hour (provided at 2-hourly intervals post-exercise), but no further increase when cho intake was increased to 0.7 g/kg bw/hour. similarly, ivy et al.29 found no difference in muscle glycogen synthesis rate between the ingestion of 0.75 vs. 1.5 g cho/kg bw/hour (provided at 2-hourly intervals) over a 4-hour period post-exercise. these two studies3,29 suggested a 'glycogen synthesis threshold' and an upper limit for cho ingestion of between ~ 0.35 0.7 g/kg bw/hour. however, several more recent studies42,48,51,53 have demonstrated glycogen synthesis rates beyond those reported in these two studies (~ 145 170% higher) when 1 1.7 g cho/kg bw/hour was ingested, hence providing evidence against the existence of such an upper limit or threshold. for example, van loon et al.53 demonstrated a ~ 200% increase in the rate of glycogen synthesis when cho intake was increased from 0.8 to 1.2 g/kg bw/hour (~ 145% higher than blom et al.3 and ivy et al.29). several others have reported even higher rates of muscle glycogen synthesis (~ 170% higher) when 1 1.7 g cho/kg bw/hour was ingested at 15 60-minute intervals during a 3 4-hour recovery period.31,42,53 in these studies, the cho beverages were provided at 15 60-minute intervals post-exercise, as opposed to 2-hourly intervals as in the studies where no difference in rates of muscle glycogen synthesis were found.3,29 additionally, ivy et al.29 reported that if beverages are provided on a 2-hourly basis, then a cho intake of > 0.5 g cho/kg bw/hour is needed in order to maximise glycogen synthesis post-exercise. collectively taken, these results may highlight the possibility that frequent cho ingestion in the early hours postexercise may be better able to increase and maintain glucose availability and insulin concentrations, as opposed to when provided on a 2-hourly basis. although the exact amount of cho to maximise postexercise glycogen recovery has not been fully established yet, the abovementioned evidence suggests that optimal muscle glycogen synthesis will be achieved by the ingestion of 1 1.5 g cho/kg bw immediately after exercise, followed by 0.8 1.5 g cho/kg bw/hour (ideally divided into small doses every 15 60 minutes) for at least 3 4 hours thereafter, aiming for a total of 7 10 g cho/kg bw over a 24-hour period. type of cho ingested the type of cho ingested plays an important role in the rate of glycogen synthesis as it affects the rate of digestion and absorption of the cho, and ultimately glucose availability. as mentioned earlier, glucose availability is an important determinant of glycogen synthesis. furthermore, insulin stimulates glycogen synthase,2 which is considered the ratelimiting enzyme in the glycogen synthetic pathway,20 as well as glut-4 translocation which facilitates glucose uptake.21 high glycaemic index (gi) cho-rich foods elicit a high glucose and insulin response within the first 2 hours after ingestion.6 thus, using high gi cho foods during the early recovery period should increase the rate of glycogen synthesis and thereby achieve a higher glycogen concentration sooner, compared with a low gi cho food. blom and co-workers3 found that the ingestion of glucose (high gi) and sucrose (moderate gi) feedings after prolonged exercise increased the rate of glycogen synthesis significantly higher at 6 hours post-exercise compared with fructose (low gi) feeding. surprisingly, sucrose (moderate gi), which contains equimolar amounts of fructose (low gi) and glucose (high gi), resulted in similar rates of glycogen synthesis and muscle glycogen levels than a similar amount of glucose (high gi). a possible explanation for this result may be that fructose inhibits post-exercise hepatic glucose uptake, thereby increasing the amount of glucose available for muscle glycogen synthesis.3 interestingly, piehl aulin and co-workers42 found that a post-exercise cho drink containing glucose polymers (high gi) resulted in a significantly higher rate of glycogen synthesis 4 hours post-exercise compared with an isocaloric glucose-containing drink (high gi) (50 vs. 30 mmol/kg dry weight/hour). it was suggested that the lower osmolality of the glucose polymer drink versus the glucose drink (84 vs. 350 mosm/l) led to greater gastric emptying rates and a faster delivery of substrate to muscle. although there was no difference in insulin and glucose response, there could have been a greater non-insulin dependent uptake of glucose in the muscle during the early (30 60 minutes) post-exercise period. this hypothesis merits further investigation. during a longer recovery period (> 6 hours) timing and type of cho ingested seems to be of lesser importance than the amount ingested.9,17,33,40 after strenuous glycogen-depleting exercise, the ingestion of 7 10 g cho/kg bw/day will be sufficient to restore glycogen stores over a 24 48-hour period.9,10,33 for athletes participating in less strenuous exercise lasting 60 120 minutes/day, the ingestion of 6 8 g cho/kg bw/day would be sufficient to restore glycogen stores within this time frame.7 there are limited data available on the role of the gi during longer recovery periods, probably due to practical difficulties, but also due to evidence9,15,18 suggesting that amount of cho ingested is more important than the type (gi) of cho itself during these periods. in summary, for athletes who train/compete twice (or more) a day, and/or have a strenuous day-to-day training or competition schedule with limited recovery time, it is recommended to opt for cho-rich foods of moderate to high gi within the first 6 hours post-exercise. after 6 hours, foods with low gi can be included, provided that the overall cho requirement (~ 7 10 g cho/kg bw within 24 hours) is met. for athletes who have 6 or more hours to recover before a subsequent strenuous exercise bout, the type of cho (low or high gi) is of lesser importance, provided that the amount of cho to be ingested within a 24-hour period be sufficient (~ 6 8 g cho/kg bw per 24 hours for moderate-intensity exercise or 7 10 g cho/kg bw per 24 hours for more strenuous/prolonged exercise). effect of combining cho and protein on muscle glycogen storage though insulin secretion is mainly determined by cho ingestion and blood glucose concentration, it has been shown that certain amino acids51-54 and/or protein peptides52,54,57 have a synergistic effect on insulin concentration when combined with cho. as mentioned before, insulin stimulates glycogen synthase and muscle glucose uptake, thus enhanced insulin release post-exercise may therefore increase the rate of muscle glycogen synthesis.31,51-53,57 zawadski and co-workers57 were the first researchers to find that the addition of whey protein to a cho supplement (112 g cho + 40.7 g protein/serving) taken immediately and 2 hours after an hour of glycogen-depleting exercise increased the rate of glycogen synthesis during a 4-hour recovery period compared with a cho-only supplement (112 g cho/serving). however, the increased rate of glycogen synthesis could have been due to the added energy, since the two drinks were not isocaloric. since then, only one other study27 found that muscle glycogen concentrations were higher (4 hours post-exercise) in a cho supplement with added protein (80 g cho + 28 g protein + 6 g fat/serving) compared with an isocaloric cho-only (108 g cho + 6 g fat/serving) supplement given immediately and 2 hours after a 2.5 hour glycogen-depleting cycling protocol. unfortunately, the rate of glycogen synthesis was not reported. subsequently, van loon et al.53 provided beverages at 30minute intervals up to 270 minutes post-exercise and compared the ingestion of 0.8 g cho/kg bw/hour with 0.8 g cho/kg bw/hour plus 0.4 g/kg bw/hour of wheat protein hydrolysate plus leucine and phenylalanine (proven to be highly insulinotrophic),54 and with 1.2 g cho/kg bw/hour. adding the protein mixture (0.4 g/kg bw/hour) to the cho beverage (0.8 g/kg bw/hour) increased the plasma insulin response and muscle glycogen synthesis rate by ~ 113% compared with the ingestion of 0.8 g cho/kg bw/hour only. however, increasing the cho content by 0.4 g cho/kg bw/hour to 1.2 g/kg bw/hour also resulted in a faster rate of muscle glycogen synthesis of ~ 170% compared with ingestion of 0.8 g cho/kg bw/hour.53 this study clearly demonstrated that maximal rates of muscle glycogen synthesis are not reached when 0.8 g cho/kg bw/hour is ingested, and that this rate can be increased by the addition of 0.4 g/kg bw/hour of either protein or more cho. the question then arose whether the addition of protein/amino acids to a larger cho beverage (> 1 g cho/kg bw/hour) would further increase the rate of muscle glycogen synthesis. in answer to this question, jentjens et al.31 demonstrated that combining 0.4 g/kg bw/hour of an insulinotrophic protein-amino acid mixture with a cho beverage containing 1.2 g cho/kg bw/hour, given at 30-minute intervals post-exercise, does not increase the rate of muscle glycogen further, despite 30 sports medicine vol 16 no.2 2004 sports medicine vol 16 no.2 2004 31 much higher insulin concentrations. the majority of studies11,31,46,48,50-53 investigating the effect of combining protein and/or amino acid-mixtures with a cho supplement have not shown an enhanced rate of glycogen synthesis when the amount of cho ingested was above 1 g/kg bw/hour. despite higher insulin concentrations, the rate of muscle glycogenesis in these studies was unaffected by the addition of protein/amino acids compared with an isocaloric cho beverage. furthermore, tarnopolsky and coworkers48 found significantly higher glycogen concentrations (4 hours post-exercise) after ingesting a cho-only (1 g cho/kg bw/serving) compared with an isocaloric cho-protein (0.75 g cho + 0.1 g protein + 0.02 g fat/kg bw/serving) supplement after a glycogen-depleting exercise protocol. these results are supported wojcik and co-workers,56 and may suggest that insulin is not the rate-limiting factor for muscle glycogen synthesis when the overall rate of cho intake is high (> 1 g cho/kg bw/hour). though the rate of glycogen synthesis might not be enhanced by adding protein and/or amino-acid mixtures to a cho supplement, it might be of practical importance, since a lower volume supplement/drink can be ingested post-exercise, when most athletes experience loss of appetite,34 and still result in efficient recovery of glycogen stores. furthermore, adding protein to a recovery supplement/drink might be beneficial for muscle repair post-exercise. this will be discussed in more detail in part ii. effect of combining cho, protein and fat on glycogen storage co-ingestion of fat reduces the plasma glucose response (but not insulin secretion) to both high and low gi cho foods, possibly due to delayed gastric emptying.14 the addition of fat and protein to a cho meal may cause similar levels of glycogen storage at 24 hours post-exercise compared with a cho-only diet, provided that the cho intake is adequate.8;46 effect of type of exercise on glycogen storage type of exercise also has an effect on rate and amount of muscle glycogen stored post-exercise. the rate of glycogen synthesis after short-term high-intensity exercise is higher than after prolonged or resistance exercise.41 possible factors contributing to this effect include higher peak blood glucose and insulin levels post-exercise, higher levels of glycolytic intermediates and lactate concentration in muscle and blood, as well as greater glycogen depletion in glycogen synthase-rich fast-twitch glycolytic muscle fibres (for review see pascoe and gladden41). additionally, eccentric exercise (usually part of resistance training) is associated with reduced rates of glycogen resynthesis.16;39 potential mechanisms include competition between inflammatory cells and muscle cells for available glucose,16 a metabolic shift towards glycogenolysis induced by inflammatory cells,47 reduced glut-4 levels,1 and an increase in calcium which could inhibit glycogen synthase.44 conclusions prolonged, strenuous exercise results in muscle glycogen depletion. recovery of these stores prior to the next training session or competition is crucial to optimise exercise performance. nutrition is a major contributor to the recovery of muscle glycogen stores and the rate at which it occurs, which is especially important for athletes engaging in multiday training or competition schedules. the rate of glycogen storage can be increased by ingesting a sufficient amount of cho (> 0.8 g cho/kg bw/hour) immediately post-exercise at 15 60-minute intervals during the first 3 4 hours of the recovery period. ingesting high gi cho during the early recovery period (≤ 6 hours) results in a higher rate of glycogen storage than low gi cho. the total amount of glycogen stored within a 24-hour period post-exercise is, however, not dependent on the gi per se, but rather on the amount of cho ingested during the recovery period. thus, the gi only seems to be important when there is a short recovery period (< 6 hours) between training sessions. finally, combining cho and protein post-exercise does not seem to result in a higher rate of glycogen storage compared with when a high cho-only supplement is ingested at a rate of >1 g cho/kg bw/hour. this combination may, however, still be of benefit to the muscle recovery process since cho and amino acid availability are important for muscle repair during the recovery period, as will be discussed in detail in part ii. references 1. asp s, daugaard jr, kristiansen s, kiens b, richter ea. exercise metabolism in human skeletal muscle exposed to prior eccentric exercise. j physiol 1998; 509 ( pt 1):305-13. 2. bak jf, moller n, schmitz o, richter ea , pedersen o. effects of hyperinsulinemia and hyperglycemia on insulin receptor function and glycogen synthase activation in skeletal muscle of normal man. metabolism 1991; 40: 830-5. 3. blom pc, hostmark at, vaage o, kardel kr, maehlum s. effect of different post-exercise sugar diets on the rate of muscle glycogen synthesis. med sci sports exerc 1987; 19: 491-6. 4. bosch an, dennis sc, noakes td. influence of carbohydrate ingestion on fuel substrate turnover and oxidation during prolonged exercise. j appl physiol 1994; 76: 2364-72. 5. bosch an, weltan sm, dennis sc, noakes td . fuel substrate kinetics of carbohydrate loading differs from that of carbohydrate ingestion during prolonged exercise. metabolism 1996; 45: 415-23. 6. brand miller j, foster-powell k, colagiuri s. the gi factor. rydalmere, nsw: hodder and stoughton, 1996. 7. burke lm. fine tuning — how much and when? the complete south african guide to sports nutrition. cape town: oxford university press, 1998: 38-62. 8. burke lm, collier gr, beasley sk, et al. effect of coingestion of fat and protein with carbohydrate feedings on muscle glycogen storage. j appl physiol 1995; 78: 2187-92. 9. burke lm, collier gr, davis pg, fricker pa, sanigorski aj, hargreaves m. muscle glycogen storage after prolonged exercise: effect of the frequency of carbohydrate feedings. am j clin nutr 1996; 64: 115-9. 10. burke lm, collier gr, hargreaves m. muscle glycogen storage after prolonged exercise: effect of the glycemic index of carbohydrate feedings. j appl physiol 1993; 75: 1019-23. 11. carrithers ja, williamson dl, gallagher pm, godard mp, schulze ke, trappe sw. effects of postexercise carbohydrate-protein feedings on muscle glycogen restoration. j appl physiol 2000; 88: 1976-82. 12. cartee gd, young da, sleeper md, zierath j, wallberg-henriksson h, holloszy jo. prolonged increase in insulin-stimulated glucose transport in muscle after exercise. am j physiol 1989; 256: e494-9. 13. coggan ar, coyle ef. carbohydrate ingestion during prolonged exercise: effects on metabolism and performance. exerc sport sci rev 1991; 19: 140. 32 sports medicine vol 16 no.2 2004 14. collier g, mclean a, o'dea k. effect of co-ingestion of fat on the metabolic responses to slowly and rapidly absorbed carbohydrates. diabetologia 1984; 26: 50-4. 15. costill dl. carbohydrates for exercise: dietary demands for optimal performance. int j sports med 1988; 9: 1-18. 16. costill dl, pascoe dd, fink wj, robergs ra, barr si, pearson d. impaired muscle glycogen resynthesis after eccentric exercise. j appl physiol 1990; 69: 46-50. 17. costill dl, sherman wm, fink wj, maresh c, witten m, miller jm. the role of dietary carbohydrates in muscle glycogen resynthesis after strenuous running. am j clin nutr 1981; 34: 1831-6. 18. coyle ef. timing and method of increased carbohydrate intake to cope with heavy training, competition and recovery. j sports sci 1991; 9: 29-51. 19. coyle ef, hagberg jm, hurley bf, martin wh, ehsani aa, holloszy jo. carbohydrate feeding during prolonged strenuous exercise can delay fatigue. j appl physiol 1983; 55: 230-5. 20. danforth wh. glycogen synthetase activity in skeletal muscle. interconversion of two forms and control of glycogen synthesis. j biol chem 1965; 240: 588-93. 21. friedman je, neufer pd, dohm gl. regulation of glycogen resynthesis following exercise. dietary considerations. sports med 1991; 11: 232-43. 22. gandevia sc. spinal and supraspinal factors in human muscle fatigue. physiol rev 2001; 81: 1725-89. 23. goodyear lj, hirshman mf, king pa, horton ed, thompson cm, horton es. skeletal muscle plasma membrane glucose transport and glucose transporters after exercise. j appl physiol 1990; 68: 193-8. 24. houston me. gaining weight: the scientific basis of increasing skeletal muscle mass. can j appl physiol 1999; 24: 305-16. 25. ivy jl. glycogen resynthesis after exercise: effect of carbohydrate intake. int j sports med 1998; 19: suppl 2: s142-5. 26. ivy jl. dietary strategies to promote glycogen synthesis after exercise. can j appl physiol 2001; 26: suppl: s236-45. 27. ivy jl, goforth hw jun., damon bm, mccauley tr, parsons ec, price tb. early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement. j appl physiol 2002; 93: 1337-44. 28. ivy jl, katz al, cutler cl, sherman wm , coyle ef. muscle glycogen synthesis after exercise: effect of time of carbohydrate ingestion. j appl physiol 1988; 64: 1480-5. 29. ivy jl, lee mc, brozinick jt jun., reed mj. muscle glycogen storage after different amounts of carbohydrate ingestion. j appl physiol 1988; 65: 2018-23. 30. jentjens r, jeukendrup a. determinants of post-exercise glycogen synthesis during short-term recovery. sports med 2003; 33: 117-44. 31. jentjens rl, van loon lj, mann ch, wagenmakers aj, jeukendrup ae. addition of protein and amino acids to carbohydrates does not enhance postexercise muscle glycogen synthesis. j appl physiol 2001; 91: 839-46. 32. kentta g, hassmen p. overtraining and recovery. a conceptual model. sports med 1998; 26: 1-16. 33. kiens b, richter ea. utilization of skeletal muscle triacylglycerol during postexercise recovery in humans. am j physiol 1998; 275: e332-7. 34. king na, burley vj, blundell je. exercise-induced suppression of appetite: effects on food intake and implications for energy balance. eur j clin nutr 1994; 48: 715-24. 35. kuipers h, keizer ha. overtraining in elite athletes. review and directions for the future. sports med 1988; 6: 79-92. 36. kuo ch, hunt dg, ding z, ivy jl. effect of carbohydrate supplementation on postexercise glut-4 protein expression in skeletal muscle. j appl physiol 1999; 87: 2290-5. 37. nielsen jn, richter ea. regulation of glycogen synthase in skeletal muscle during exercise. acta physiol scand 2003; 178: 309-19. 38. nybo l, moller k, pedersen bk, nielsen b, secher nh. association between fatigue and failure to preserve cerebral energy turnover during prolonged exercise. acta physiol scand 2003; 179: 67-74. 39. o'reilly kp, warhol mj, fielding ra, frontera wr, meredith cn, evans wj . eccentric exercise-induced muscle damage impairs muscle glycogen repletion. j appl physiol 1987; 63: 252-6. 40. parkin ja, carey mf, martin ik, stojanovska l, febbraio ma. muscle glycogen storage following prolonged exercise: effect of timing of ingestion of high glycemic index food. med sci sports exerc 1997; 29: 220-4. 41. pascoe dd, gladden lb. muscle glycogen resynthesis after short term, high intensity exercise and resistance exercise. sports med 1996; 21: 98118. 42. piehl aulin k, soderlund k, hultman e. muscle glycogen resynthesis rate in humans after supplementation of drinks containing carbohydrates with low and high molecular masses. eur j appl physiol 2000; 81: 346-51. 43. price tb, rothman dl, taylor r, avison mj, shulman gi, shulman rg. human muscle glycogen resynthesis after exercise: insulin-dependent and -independent phases. j appl physiol 1994; 76: 104-11. 44. roach pj. control of glycogen synthase by hierarchal protein phosphorylation. faseb j 1990; 4: 2961-8. 45. romijn ja, coyle ef, sidossis ls, et al. regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration. am j physiol 1993; 265: e380-91. 46. roy bd, tarnopolsky ma. influence of differing macronutrient intakes on muscle glycogen resynthesis after resistance exercise. j appl physiol 1998; 84: 890-6. 47. shearer jd, amaral jf, caldwell md. glucose metabolism of injured skeletal muscle: the contribution of inflammatory cells. circulatory shock 1988; 25: 131-8. 48. tarnopolsky ma, bosman m, macdonald jr, vandeputte d, martin j, roy bd. postexercise protein-carbohydrate and carbohydrate supplements increase muscle glycogen in men and women. j appl physiol 1997; 83: 1877-83. 49. tipton kd, wolfe rr. exercise, protein metabolism, and muscle growth. international journal of sport nutriton and exercise metabolism 2001; 11: 109-32. 50. van hall g, saris wh, van de schoor pa, wagenmakers aj. the effect of free glutamine and peptide ingestion on the rate of muscle glycogen resynthesis in man. int j sports med 2000; 21: 25-30. 51. van hall g, shirreffs sm, calbet ja. muscle glycogen resynthesis during recovery from cycle exercise: no effect of additional protein ingestion. j appl physiol 2000; 88: 1631-6. 52. van loon lj, kruijshoop m, verhagen h, saris wh, wagenmakers aj. ingestion of protein hydrolysate and amino acid-carbohydrate mixtures increases postexercise plasma insulin responses in men. j nutr 2000; 130: 2508-13. 53. van loon lj, saris wh, kruijshoop m, wagenmakers aj. maximizing postexercise muscle glycogen synthesis: carbohydrate supplementation and the application of amino acid or protein hydrolysate mixtures. am j clin nutr 2000; 72: 106-11. 54. van loon lj, saris wh, verhagen h, wagenmakers aj. plasma insulin responses after ingestion of different amino acid or protein mixtures with carbohydrate. am j clin nutr 2000; 72: 96-105. 55. weltan sm, bosch an, dennis sc, noakes td. influence of muscle glycogen content on metabolic regulation. am j physiol 1998; 274: e72-82. 56. wojcik jr, walber-rankin j, smith ll, gwazdauskas fc. comparison of carbohydrate and milk-based beverages on muscle damage and glycogen following exercise. international journal of sport nutrition and exercise metabolism 2001; 11: 406-19. 57. zawadzki km, yaspelkis bb iii, ivy jl. carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise. j appl physiol 1992; 72: 1854-9. sajsm vol 18 no. 4 2006 129 introduction in recent years findings on seasonal cricket injuries have been well documented in south africa, 10-16 australia 5 and england. 3 variation in injury definitions and methods of data collection have limited the ability to draw comparisons relating to injury rate. however, the recently published consensus statement on the method of injury surveillance in international cricket should address this and allow meaningful comparisons to be made. 6 a further area of concern and where there is a paucity of literature is that relating to cricket injuries while on international tours, specifically evidence describing the expected medical treatments at large tournaments such as the world cup. on the first tour (8 days) after south africa’s re-admission to international cricket, 8 of the 16 players, as well as the coach of the south african team received 31 treatments. 9 of the 14 injuries to the players, which were defined as conditions requiring medical or physiotherapy treatment, 7 (50%) were bone/joint injuries, 3 were tendon injuries, 1 muscle, 1 ligament and 2 soft-tissue injuries, with the most commonly injured area being the lower limb (64%). the injury rate was 1 injury per player. on a 5-week international tour to south africa, a total of 40 injuries were incurred by 16 players who received 166 treatments at an incidence rate of 2.5 injuries per player and 10.4 treatments per player. of these, 24 were minor injuries, which took 3 or less treatments to heal, and 16 were major injuries, which took more than 3 treatments to heal and may have prevented participation in a match. the injuries were mainly bone/joint injuries (n = 14), muscle (n = 8), tendon (n = 6), ligament (n = 5) and 'other' (n = 7) injuries. 7 of the 40 injuries, 20% were injuries from the previous season that were re-aggravated. the south african team to the world cup in australasia and then the subsequent tour to the caribbean consisted of 14 players, with 2 additional players to learn and assist with practices. original research article analysis of patient load data for teams competing in the 2003 cricket world cup in south africa a kilian (mb chb)1 r a stretch (dphil)2 1 private practice, port elizabeth 2 sport bureau, nelson mandela metropolitan university, port elizabeth abstract objectives. to evaluate the injury presentation data for all teams taking part in 10 warm-up matches and 46 matches during the 2003 cricket world cup played in south africa, in order to provide organisers with the basis of a sound medical-care plan for future tournaments of a similar nature. methods. the data collected included the role of the injured person, the nature of the injury, whether the treatment was for an injury or an illness, whether the injury was acute, chronic or acute-on-chronic, and the prognosis (rest, play, unfit to play, sent home, follow-up treatment required). the medical personnel in charge of the medical support documented patient information which included the total number of patient presentations and the category of illness/injury. results. ninety patient presentations (1.6 patient presentations per match) were recorded. the most common patient presentations were by the batsmen (50%), followed by the bowlers (29%) and all-rounders (17%). of the patient presentations, 53% were classified as injuries, while the remaining 47% were classified as illnesses. the patient presentations occurred in the early stages of the competition. the most common presentations were of an acute nature (63%). the main injury pathology categories were trigger point injuries (10%), and bruises / abrasions (10%), while infection (29%) was the main illness pathology. conclusions. the 2003 cricket world cup proved to be an ideal opportunity to collect data on international correspondence: r a stretch sport bureau nelson mandela metropolitan university po box 77000 port elizabeth 6031 tel: 041-504 2584 fax: 041-504 1784 e-mail: richard.stretch@nmmu.ac.za cricketers participating in an intensive 6-week international competition; the epidemiological data collected should assist national cricket bodies and organisers of future cricket world cup competitions to predict participantrelated injury rates. 130 sajsm vol 18 no. 4 2006 on the initial part of the tour, made up of 6 warm-up matches and 9 world cup matches, the 16 players sustained 56 injuries, which were not defined, at an injury rate of 3.5 injuries per player. the most commonly injured area was the lower limb (50%), comprising 16 bone / joint and 23 muscle injuries. 8 the caribbean part of the tour consisted of 3 one-day internationals and a 5-day test match. eleven of the 14 players sustained 15 injuries, which were not defined, at an injury rate of 1 injury per player. the lower limb (33%) was the most commonly injured area, comprising 9 bone/joint and 3 muscle injuries. 8 on a 15-day tour of south africa an english county team played 10 days of matches and trained on each of the other days. thirteen of the 17 players on tour sustained 22 injuries, which were not defined, which required 92 treatments. only 1 of the injuries prevented the player from playing. the lower limb was the most commonly injured area (45%), with 10 bone/joints and 9 muscle injuries. 1 the evidence shows that the number of injuries per player is proportional to the length of the tour and that lower-limb injuries as a result of fielding were the most common injuries on tours. 2,8 the seasonal rate of injury to cricket players has been well documented over the past number of years, 3,5,10-16 with the recent study on west indies cricket 1 being the first to adhere to the internationally acceptable injury surveillance method and definition of injury. however, the literature on the injury rate of participants in a major cricket tournament is limited to only 1 team per tournament or tour. 2,7-9 thus the purpose of this study was to evaluate the presentation data for all teams taking part in the 2003 cricket world cup played in south africa, in order to provide organisers with the basis of a sound medical-care plan for future tournaments of a similar nature. method the 2003 cricket world cup was held in february and march 2003, with 54 matches staged in south africa, zimbabwe and kenya. only the matches played in south africa formed part of this study. the latter included 10 warm-up matches played prior to the competition, 34 first-round matches, 9 matches played during the super 6's and then the 2 semi-finals and the final (56 matches). the one-day international matches were played over 50-overs and were either played as day matches (from 10h00 to about 17h30) or as day-night matches (fromfrom 10h00 to about 17h30) or as day-night matches (from 14h30 to about 22h00). all the planning and procedures relating to the medical management of the spectators and players for all matches were the responsibility of the medical committee, with only the player data presented in this study. the medical committee held monthly meetings from january 2002 to may 2003 (16 meetings) and 3 seminars with the medical personnel prior to the start of the competition. based on this a medical system was put in place in each city to cater for the needs of the players 24 hours a day. medical support was provided from the time that the teams arrived in the country, and the medical staff were available 24 hours a day. on match days a doctor was available to both teams for the full duration of the match. the necessary table i. demographic information and patient presentations at the 2003 cricket world cup warm-up first-round super 6’s semi-final final total injuries country (n) (n) (n) (n) (n) n % australia 2 8 2 12 13 bangladesh 3 3 4 canada 4 8 12 13 england 1 10 11 12 holland india 2 5 3 2 12 13 kenya 2 3 5 6 namibia 1 1 1 new zealand 12 1 13 14 pakistan 1 1 1 south africa 3 3 4 sri lanka 2 3 3 8 9 west indies 1 8 9 10 zimbabwe total 12 64 12 2 90 100 % (total injuries) 13 72 13 2 100 presentations/match 1.2 1.9 1.3 1 1.6 132 sajsm vol 18 no. 4 2006 medical supplies and equipment were available at each medical station. an ambulance was available at each venue to transfer patients to hospital if necessary. further, at least 1 hospital in each city was put on standby in the event of an emergency, with the normal daily staff on standby. data collected included the following: role of the injured person (batsman, bowler, all-rounder, wicket-keeper or official), nature of the injury, whether the treatment was for an injury or an illness, whether the injury was acute, chronic or acute-on-chronic, and the prognosis (rest, play, unfit to play, sent home, follow-up treatment required). the medical personnel in charge of the medical support documented patient information which included the total number of patient presentations and the category of illness/injury. in order to allow comparison with other cricket injury surveys the illness/ injury data as recommended in the consensus papers 6 were classified using the osics (orchard sports injury classification system). 4 results the results are shown in tables i iv. the results do not reflect any injuries and illnesses that may have been treated within the medical infrastructure of the teams, and thus the data reported could be an underestimation. however, in all probability these would have been minor day-to-day treatments such as for muscle aches and pains, headaches, etc. of the 14 teams participating only 2 teams did not record any patient presentations during the data collection period. ninety patient presentations were recorded, with 86 recorded for players and 4 for officials. of these, 13% occurring during the 10 warm-up matches, 72% during the 34 first-round matches, 13% during the 9 super 6’s matches and 2% during the semi-finals. there were no patient presentations prior to or during the final. thus there were 1.6 patient presentations per match for the 56 matches. fifty-five players/officials recorded 1 patient presentation each, 14 recorded 2 patient presentations each, and the other 2 players recorded 3 and 4 patient presentations each. the most common patient presentations were by the batsmen (50%), followed by the bowlers (29%) and allrounders (17%). no wicket-keeper presented with a medical condition, while 4% of the patient presentations were by officials. of the patient presentations 53% were classified as injuries, while the remaining 47% were classified as illnesses. the most common presentations were of an acute nature (63%), with the rest being chronic (14%) and acute-onchronic (23%). the main injury pathology categories for patient presentations were trigger point injuries (10%), bruises / abrasions (10%), soft-tissue injuries including muscle strains (7%), haematoma (6%), and tendinopathy (4%). the main illness pathology categories for patient presentations were infection (29%), primarily consisting of otorespiratory, gastrointestinal and genitourinary infections, and dermatology (8%). fifty-seven per cent of presenting patients were able to continue to play immediately, 24% were able to resume play again after a period of rest, while 7% needed further followup medical attention before being able to play again. eight per cent were not able to take part in any further matches, and 4% of injuries involved officials. table ii. medical conditions and patient presentations at the 2003 cricket world cup patient presentations n % number of patient presentations one patient presentation (1 x 55) 55 61 two patient presentations (2 x 14) 28 31 three patient presentations (3 x 1) 3 4 four patient presentations (4 x 1) 4 4 chronicity of patient presentations injuries 48 53 acute 30 33 chronic 3 3 acute-on-chronic 15 17 illnesses 42 47 acute 27 30 chronic 10 11 acute-on-chronic 5 6 pathology category injuries 48 53 trigger points 9 10 bruises/abrasions 9 10 muscle strain 6 7 haematoma 5 6 acute fracture 5 6 tendinopathy 4 4 laceration 3 3 other 7 7 illnesses 42 47 infection 26 29 dermatology 7 8 other 9 10 prognosis continue to play 51 57 rest 22 24 unfit to play 7 8 follow-up treatment 6 7 team official 4 4 sajsm vol 18 no. 4 2006 133 discussion the primary findings here indicate that the patient presentations occurred in the early stages of the competition, batsmen were more susceptible to injury/illness than bowlers, and illnesses accounted for nearly half of the participant presentations. most injuries were of an acute or acute-onchronic nature. in preparation for the tournament there is a need to develop the team, and to achieve this most teams take part in pre-world cup matches in order to try out various combinations and to give players the opportunity to develop experience in pressure situations. this increase in training and match-play volume and intensity in order to ensure that the team arrives at the world cup with the correct batting and bowling combinations may be one of the predisposing injury factors. this increased workload could result in players sustaining minor injuries that escalate into more serious injuries when participating in the high-intensity world cup matches. as the world cup is held only every 4 years, the desire among players to take part in the event may result in their not disclosing ‘niggles’ or minor injuries in order to ensure selection. in order to avoid this situation, the preworld cup schedule of teams needs to be planned carefully, with the players not arriving over-trained. the findings here indicate that batsmen were more susceptible to injury/illness. this is different to the literature on seasonal risk of injury 3,5,10-16 which shows that bowlers, particularly fast bowlers, are at the greatest risk of injury. because of the format of the world cup tournament, bowlers are not likely to sustain chronic over-use injuries due to the limit of 10 overs per match for each bowler and the relatively long time between matches which allows the bowlers to recover fully. however, the larger number of acute injuries would be as a result of the intense nature of the world cup matches, particularly from a batting and fielding perspective. when batting the players have to take quick runs, often for extended periods, predisposing them to acute soft-tissue injuries. illnesses accounted for nearly half of the participant presentations, with infections constituting the primary cause of these participant presentations. during the initial part of the tour the players are generally busy trying to acclimatise to foreign conditions while continuing with an intense programme of fitness, skill and match preparation, and as a result may be susceptible to various infections. one way to reduce the risk may be for clothing manufacturers to adapt the playing clothing to meet this need. bowlers, on the other hand, are able to take off and put on their jerseys between overs and their high-intensity bowling spells. table iii. type of injuries and illnesses and stage at which injuries and illnesses were sustained during the 2003 cricket world cup warm-up / first round super 6’s semi-final / final total injuries (n) 39 6 3 48 head / neck 5 5 chest 1 1 back 8 8 shoulder /arm 4 2 6 hand / finger 6 2 3 11 groin / upper leg 2 1 3 knee / shin 8 1 9 ankle / foot 5 5 illnesses (n) 39 3 42 urti 11 2 13 dermatology 7 7 gastrointestinal 5 1 6 eye 3 3 uti 3 3 fatigue/insomnia 3 3 bee sting/tick-bite 3 3 mouth sores 2 2 hernia 2 2 total (n) 78 9 3 90 urti = upper respiratory tract infection, uti = urinary tract infection. 134 sajsm vol 18 no. 4 2006 collection of data on medical conditions and injuries in cricket players is difficult due to the unique nature of cricket which is played over an extended match period, with the players often on long tours, both at home and abroad, without an accompanying doctor. the 2003 cricket world cup proved to be an ideal opportunity to collect data on international cricketers participating in an intensive 6-week international competition, and the epidemiological data collected should assist national cricket bodies and organisers of future cricket world cup competitions to predict participant-related injury rates. references 1. mansingh a, harper l, headley s, king-mowatt j, mansingh g. injuries in west indies cricket 2003-2004. br j sports med 2006; 40: 119-23. 2. morton j. cricket injuries of the northamptonshire county cricket team morton j. cricket injuries of the northamptonshire county cricket teammorton j. cricket injuries of the northamptonshire county cricket team during a 15 day tour of natal. south african journal of sports medicine 1992; 7: 18 20. 3. newman da. prospective survey of injuries at first class counties in newman da. prospective survey of injuries at first class counties innewman da. prospective survey of injuries at first class counties in england and wales 2001 and 2002 seasons. in: stretch ra, noakes td, vaughan cl, eds. science and medicine in cricket. cape town: compress, 2003: 343-50. 4. orchard j. orchard sports injury classification system (osics). in: orchard j. orchard sports injury classification system (osics). in:orchard j. orchard sports injury classification system (osics). in: bloomfield j, fricker p, fitch k, eds. science and medicine in sport. 2nd ed. melbourne: blackwell, 1995, 674 8. 5. orchard j, james t, alcott e, carter s, farhart p. injuries in australian orchard j, james t, alcott e, carter s, farhart p. injuries in australianorchard j, james t, alcott e, carter s, farhart p. injuries in australian cricket at first class level 1995/1996 to 2000/2001. br j sports med 2002; 36: 270-5. 6. orchard jw, newman d, stretch r, frost w, manshing a, leious a. orchard jw, newman d, stretch r, frost w, manshing a, leious a.orchard jw, newman d, stretch r, frost w, manshing a, leious a. methods for injury surveillance in international cricket. j sci med sport 2005; 8: 1 -14. 7. smith c. sports injuries encountered on a five week international cricket smith c. sports injuries encountered on a five week international cricketsmith c. sports injuries encountered on a five week international cricket tour. south african journal of sports medicine 1990, 6 (1): 10 5. 8. smith c. cricket injuries of the south african team at the world cup and smith c. cricket injuries of the south african team at the world cup andsmith c. cricket injuries of the south african team at the world cup and in the caribbean: the physiotherapy perspective. south african journal of sports medicine 1991; 7: 20 4. 9. smith c. cricket injuries while on tour with the south african team in india. smith c. cricket injuries while on tour with the south african team in india.smith c. cricket injuries while on tour with the south african team in india. south african journal of sports medicine 1992; 7(1): 4 8. 10. stretch ra. injuries to south african cricketers playing at first-class level. stretch ra. injuries to south african cricketers playing at first-class level.stretch ra. injuries to south african cricketers playing at first-class level. south african journal of sports medicine 1989; 4: 3-20. 11. stretch ra. the incidence and nature of injuries in club and provincial cricketers. south african journal of sports medicine 1993; 83: 339-41. 12. stretch ra. the incidence and nature of injuries in schoolboy cricketers. s afr med j 1995; 85: 1182-4. 13. stretch ra. incidence and nature of epidemiological injuries to elite south african cricket players. south african journal of sports medicine 2001a; 91: 336-9. 14. stretch ra. the incidence and nature of epidemiological injuries to elite south african cricket players over a two-season period. south african journal of sports medicine 2001b; 8:17 20. 15. stretch ra. cricket injuries: a longitudinal study of the nature of injuries to south african cricketers. br j sports med 2003; 37: 250 3. 16. stretch ra, venter djl. cricket injuries: a longitudinal study of the nature of injuries to south african cricketers. south african journal of sports medicine 2003; 15: 4 8. table iv. chronicity of injuries and illnesses, role, and stage of the 2003 cricket world cup when injury was sustained warm-up / first round super 6’s semi-final / final total acute batsmen 15 2 1 18 bowlers 5 1 6 all-rounders 4 1 1 6 chronic batsmen 3 3 bowlers all-rounders acute-on-chronic batsmen 3 3 bowlers 5 1 1 7 all-rounders 3 2 5 upmarket health centre requires a doctor healthjunction, an established multi-disciplinar y health centre in the city bowl seeks an energetic, proactive doctor to set up practice. join our professional and passionate team comprising physiotherapists, biokineticists and pilates instructors. we ser vice an upmarket and active clientele. full time or sessional option. call cathy on 082 465 3745 or e-mail cathy@healthjunction.co.za original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license the knowledge and attitudes of south african-based runners regarding the use of analgesics during training and competition r thorpe,1 msc; m blockman,2 mbchb, mmed; h talberg,1 mphil; t burgess,1 phd 1 division of physiotherapy, department of health and rehabilitation sciences, university of cape town, south africa 2 division of clinical pharmacology, department of internal medicine, university of cape town, south africa corresponding author: r thorpe (rowanthorpe.physio@gmail.com) global participation in running has continued to grow over the last decade with millions of people running weekly.[1,2] this growth has been observed across all distance categories from the social 5km parkrun to 100-mile (160,9km) ultramarathons.[1,2] in 2016, nine million runners finished races globally.[3] of particular interest to sports researchers involved in training/distance and load and its link to injury is participation in long-distance running events, such as half marathons, marathons, and ultramarathons. these distance events require months of progressive training and load adjustment, which, in combination with multiple other variables, like body mass index (bmi), age, sex, pace and previous injury, may all increase the risk of the participant developing a running-related injury (rri).[4] a rri can be a source of immense psychological and psychosocial stress for runners,[5] especially when considering the physical, mental, and social benefits of running.[6] runners therefore tend to engage in various untested and ill-advised practices to continue running despite injury. the use of analgesics, including nonsteroidal anti-inflammatory drugs (nsaids), is one option that runners may consider to facilitate continued participation in running. adoption of this as an injury mitigation strategy is seen in the high and rising use of analgesics in running, and sport in general.[7,8] major concerns surrounding increased analgesic use in sports is the likelihood that this practice is unsupervised and not supported by adequate knowledge of the effects of drugs and their side effects.[9] potential adverse effects from nsaids consumption during running include increased physiological and systemic stresses with the consumption of nsaids during 10km and 21.2km races which have been shown to increase urinary neutrophil gelatinase-associated lipocalin (ungal), an indicator of acute kidney injury.[10] previously reported rationales for the use of analgesics in sport include perceived improvements in performance, and prophylactic injury management;[11] which are unsupported by scientific evidence; and further questions athletes’ knowledge of and attitudes towards the use of analgesics.[12] when combined with the ease of over-the-counter (otc) access in south africa to complex analgesics, such as multi-ingredient nsaids, this is a major cause for concern in endurance sport,[7,11] including running, where there has been limited research to date. our study aimed to determine and describe the knowledge and attitudes regarding the use of analgesics in south africanbased runners. methods study design and ethical approval the methods for this study have previously been described in full,[7] and will be summarised to avoid replication. this study obtained ethical approval from the faculty of health sciences human research ethics committee, university of cape town (hrec ref: 093/2016) and as mentioned, had a descriptive cross-sectional design. participants recruitment for the online survey was done via south african running clubs and social media platforms. inclusion in the study required that participants be south african-based runners of at least 18 years of age, with internet access, who ran at least one race of any distance, per year. a race was regarded as a competitive event that was open to any runners and background: the use of analgesics is prevalent in runners, with the associated potential for serious harm. however, there is limited information regarding runners’ knowledge and attitudes towards the use of analgesics in relation to running. objectives: to describe south african-based runners’ knowledge and attitudes regarding running-related analgesic use. methods: this study has a descriptive, cross-sectional design. south african-based runners, over the age of 18 who ran at least one race in the year preceding the study were included in this study. participants completed an online questionnaire, including sections on demographic information, training and competition history, pain medication use, and knowledge and attitudes regarding running-related analgesic use. results: data from 332 participants were analysed. attitudes regarding the use of analgesics in relation to running were generally positive; however, knowledge was poor, with only 20% of participants achieving adequate knowledge scores (75% or above). very few (n=49; 15%) had both adequate knowledge and positive attitudes, with most respondents (n=188; 58%) having inadequate knowledge and negative attitudes. negative attitudes towards the use of analgesics were found to increase the odds of running-related analgesic use (or 2.32; 95% ci:1.31-4.11). conclusion: knowledge regarding running-related use of analgesics was inadequate. despite a lack of knowledge, attitudes were positive. participants displayed positive attitudes towards safe practice regarding running-related analgesic use, but these did not translate into good practice. targeted interventions are required to educate runners and improve their knowledge of all the effects associated with running-related analgesic use. keywords: athletes, nsaids, performance, exercise s afr j sports med 2022;34:1-6. doi: 10.17159/2078-516x/2022/v34i1a13976 mailto:rowanthorpe.physio@gmail.com http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13976 https://orcid.org/0000-0003-0625-8590 https://orcid.org/0000-0002-8735-0315 https://orcid.org/0000-0001-7240-8812 https://orcid.org/0000-0001-9796-2182 original research sajsm vol. 34 no.1 2022 2 external to a single running club’s calendar. runners were excluded if informed consent was not provided, or they failed to complete the knowledge section of the survey. sample size determination sample size was calculated based on data from previous studies that determined prevalence rates of prescribed and over-the-counter nsaid use in athletes[8,11], where the required sample size was 208 participants. measurement instrumentation: questionnaire an investigator developed and an expert validated the questionnaire created to determine participants’ knowledge and attitudes regarding the use of analgesics in running, as described previously.[7] knowledge was scored by awarding participants one mark for each correct answer and zero marks for incorrect answers. participants were graded using the percentage of correct answers, i.e. 75% and above demonstrated adequate knowledge and below 75% demonstrated inadequate knowledge. this scoring system was based on previous research.[13] attitudes towards analgesics were determined by using a five-point likert scale. several statements were provided and participants needed to indicate the extent to which they agreed with each statement, ranging from ‘strongly agree’ to ‘strongly disagree’. they were also asked to state the likelihood that they would use analgesics in specific situations, ranging from ‘very unlikely’ to ‘very likely’. each point on the likert-scale was weighted, with one point being awarded for the ‘most negative’ response and five points being awarded for the ‘most positive’ response. a positive response was one that was seen to promote and be aligned with safe or healthy behaviours regarding analgesics and their use in running, whereas a negative response was seen to be aligned to potentially unsafe behaviours. percentages of 75% and above indicated positive attitudes and below 75% indicated negative attitudes. the knowledge and attitudes sections of the questionnaire can be found in appendix a. procedure the final questionnaire was uploaded to the online survey website surveymonkey® (www.surveymonkey.com) and was open for one month. it was the intention of the researchers to translate the questionnaire into afrikaans, isixhosa and isizulu. however, due to the rapid rate of responses, the study was closed to further enrolment earlier than predicted and these translations were not included in the final study. statistical analysis statistical analyses were performed using the ibm spss software (ibm corp. 2015. ibm spss statistics for windows, version 23.0. armonk, ny. www.ibm.com). a shapiro-wilk test was used to determine whether the data were normally distributed. frequency tables and pearsons’ chi-squared measures of association were used for categorical variables. odds ratios and 95% confidence intervals (95% cis) were calculated using vassarstats (http://www.vassarstats.net/ odds2x2.html) to determine associations between individual variables and analgesic use. results participants we received 450 responses; 16 responses were excluded as they fig. 1. summary of study respondents http://www.surveymonkey.com/ http://www.ibm.com/ http://www.vassarstats.net/%20odds2x2.html http://www.vassarstats.net/%20odds2x2.html original research 3 sajsm vol. 34 no.1 2022 failed to meet the inclusion criteria. during data analysis, a further 102 responses were excluded as participants failed to complete all the mandatory sections of the questionnaire. overall, 275 fully completed survey responses and 57 partially completed responses were included in the study. partially completed responses were questionnaires that were completed up until the end of the knowledge section of the questionnaire but where the final attitudes section of the questionnaire was incomplete. therefore, data from 332 participants, 196 (59%) females and 136 (41%) males, were included (figure 1). participant age ranges and training history are seen in table 1. knowledge and attitudes regarding the use of analgesics fewer than 20% (n=65) of participants demonstrated adequate knowledge regarding analgesic use. however, 73% (n=237) demonstrated positive attitudes towards the use of analgesics. only 49 participants (15%) showed both adequate knowledge and positive attitudes (table 2). regarding the participants’ specific responses, only 53% could correctly identify the possible side effects of nsaids and only 21 participants (6%) were correctly informed as to the most suitable time to take nsaids. less than 50% knew that aspirin was both an analgesic and nsaid, while only 11% were aware that intra-articular corticosteroids have less adverse effects than the oral effects. although almost twothirds of participants (63%) correctly indicated that topically administered nsaids had fewer adverse effects than orally administered nsaids, only 27% were aware that it is not recommended to use oral and topical nsaids concurrently (table 3). participants demonstrated positive attitudes regarding the use of analgesics. a total of 110 participants (33%) disagreed and 85 (26%) strongly disagreed with the statement that the prophylactic use of analgesics before a run will prevent pain during a run, while 57% and 42% of participants strongly disagreed that oral analgesics or topical analgesics are an important part of their running preparations, respectively. more than 100 participants (32%) agreed that they would only use analgesics when running if they were injured, and 33% agreed that they would use analgesics specifically for a race if they were injured. analysis of the question whether analgesics are not seen to have an important role in running, showed that 122 participants (37%) strongly disagreed with this statement, and 265 participants (80%) feel that runners are not sufficiently educated regarding the effects and side-effects of analgesics (table 4). there was a significant difference between the combined knowledge and attitudes scores (χ2 = 9.64; p = 0.022) in participants who used analgesics in running and those who did not, yet there were no significant differences in knowledge scores between these groups. there were no significant differences in the knowledge and attitude scores found between participants that made use of multiple analgesics concurrently and those who only used one type of analgesic (table 5). negative attitudes towards the use of analgesics were found to increase the odds of running-related analgesic use (or 2.32; 95% ci: 1.31-4.11) when compared to positive attitudes. discussion knowledge scores this is the first study that we are aware of that specifically grades participants’ knowledge regarding analgesic use, especially in running. scores of 75% and above for the knowledge and attitudes sections of the questionnaire were classified as adequate.[13] participants’ overall knowledge regarding analgesics was inadequate, with less than 20% of table 1. age ranges, and training and competition history of male and female respondents (n = 332) male (n=136) female (n=196) total (n=332) age (years) 39 ± 10 38 ± 10 38 ± 10 number of years of running 0 to 3 years 35 (26%) 62 (32%) 97 (29%) 4 to 9 years 47 (35%) 78 (40%) 125 (38%) 10 or more years 54 (40%) 56 (29%) 110 (33%) kilometres run per week 39 km or less 70 (52%) 121 (62%) 191 (58%) 40 km or more 66 (49%) 75 (38%) 141 (43%) marathon or ultra-marathon completion yes 75 (55%) 96 (49%) 171 (52%) no 61 (45%) 100 (51%) 161 (48%) number of marathons or ultra-marathons per participant marathons 3 ± 2 2 ± 2 3 ± 2 ultra-marathons 2 ± 2 2 ± 1 2 ± 1 data are expressed as number of responses (n) and column percentages (%) or mean ± standard deviation (sd) table 2. knowledge and attitudes scores regarding the use of analgesics participants (n=332) knowledge scores inadequate knowledge (<75%) 267 (80%) adequate knowledge (>75%) 65 (20%) attitudes scores negative attitudes (<75%) 86 (27%) positive attitudes (>75%) 237 (73%) combined knowledge (k) and attitude (a) scores poor k and a 70 (22%) poor k good a 188 (58%) good k poor a 16 (5%) good k and a 49 (15%) data are expressed as number of responses (n) and column percentages (%). column n values of <332 for participants are as a result of partially completed questionnaires. original research sajsm vol. 34 no.1 2022 4 participants scoring 75% or above. participants generally displayed good knowledge regarding the general risks of analgesic misuse and overdose, similar to what has previously been found in distance runners.[14] yet, they scored poorly on the questions concerning adverse effects, drug interactions, and the effects of specific analgesics, especially nsaids. these findings are supported by previous literature in both the general and sporting populations.[8,15] there is an awareness that there are risks when using nsaids, however, there is a lack of awareness regarding the specifics of the adverse effects. this lack of knowledge could present with significant implications as runners may not associate specific adverse effects to the use of nsaids. for example, a runner may experience abdominal pain as an adverse effect of nsaid table 3. true and false question responses (n = 332) question false true i don’t know it is safe to take over-the-counter pain medication if you have been drinking alcohol 305 (92%) 7 (2%) 20 (6%) if the recommended dose of pain medication doesn't relieve your pain, it is safe to take more 312 (94%) 4 (1%) 16 (5%) local anaesthetic injections can cause heart problems 29 (9%) 112 (34%) 191 (58%) aspirin can be both an analgesic and an antiinflammatory 53 (16%) 151 (46%) 128 (39%) panado® is a stronger pain medication than codeine 247 (74%) 7 (2%) 78 (24%) injected corticosteroids (cortisone) are safer than oral/tablet corticosteroids (cortisone) 95 (29%) 35 (11%) 202 (61%) it is possible to overdose on panado® (paracetamol) 23 (7%) 256 (77%) 53 (16%) anti-depressant medication can be used to manage pain 135 (41%) 50 (15%) 147 (44%) paracetamol and anti-inflammatories work in the same way 223 (67%) 18 (5%) 91 (27%) topical pain medication (gels and patches) have fewer side effects than other forms of pain medication 45 (14%) 210 (63%) 77 (23%) it is safe to use oral (tablets) and topical antiinflammatories at the same time 90 (27%) 95 (29%) 147 (44%) all types of topical pain medication have the same side effects 211 (64%) 13 (4%) 108 (32%) it is safer to use topical pain medication, rather than oral pain medication, if you are using other types of medication (i.e. diabetic or cholesterol medication) 40 (12%) 129 (39%) 163 (49%) data are expressed as number of responses (n) and percentages of respondents (%). the correct responses are in bold. table 4. attitudes towards analgesics in running (n = 332) statement strongly agree agree neutral disagree strongly disagree taking pain medication before a run will stop me from feeling pain during the run 5 (2%) 64 (19%) 59 (18%) 110 (33%) 85 (26%) taking pain medication before a run will stop me from feeling pain or stiffness after the run 3 (1%) 22 (7%) 57 (15%) 156 (47%) 91 (27%) oral pain medication (paracetamol/antiinflammatories) is an important part of my running preparations 5 (2%) 13 (4%) 27 (8%) 88 (27%) 190 (57%) i would use pain medication for training: if i had pain (an injury) 13 (4%) 85 (26%) 35 (11%) 78 (24%) 112 (34%) i would use pain medication for a race: if i had pain (an injury) 17 (5%) 110 (33%) 36 (11%) 55 (17%) 105 (32%) i would use pain medication as part of my recovery 13 (4%) 115 (35%) 56 (17%) 67 (20%) 72 (22%) i would only use pain medication when running if i was injured 13 (4%) 105 (32%) 42 (13%) 81 (24%) 82 (25%) using pain medication before training or a race will improve performance 2 (1%) 19 (6%) 39 (12%) 104 (31%) 159 (48%) using pain medication will speed up recovery 4 (1%) 45 (14%) 63 (19%) 103 (31%) 108 (33%) pain medication has an important role in running 7 (2%) 30 (9%) 58 (18%) 106 (32%) 122 (37%) runners are educated enough with regards to the effects and side-effects of pain medication 4 (1%) 15 (5%) 39 (12%) 130 (39%) 135 (41%) data are expressed as number of responses (n) and percentages of respondents (%). row n values of <332 for participants are as a result of partially completed questionnaires. original research 5 sajsm vol. 34 no.1 2022 use; yet, as they are unaware that the associated abdominal pain is nsaid induced, they consume further nsaids, or alternative analgesics, to manage this abdominal pain, placing them at higher risk of more serious adverse effects due to the cumulative dose or potential drug interactions. runners need also be aware of the exercise-induced stress on physiologic function because of distance running, and the further detrimental effects that nsaid consumption can have on these systems. these changes are specifically seen in the renal function of distance runners when ungal, an indicator of acute injury and tubular dysfunction, is measured. running a 21.1km race caused a significant increase in ungal that this is further increased if nsaids were consumed, showing a greater risk of kidney damage in runners.[10] attitude scores despite previous studies identifying that athletes generally demonstrate negative attitudes towards the use of analgesics,[8,11] the participants in our study had positive attitudes towards analgesic use, with 73% achieving adequate attitude scores. negative attitudes towards the use of analgesics increase the odds of running-related analgesic use. attitudes have been shown to be a variable predictor of health behaviours, and have previously been predictive of alcohol and marijuana use but were not predictive of positive or negative smoking behaviours.[16] in our study, 143 participants (68%) used analgesics in running despite having positive attitudes towards their use. this behaviour could link to the stereotype that athletes will do anything to achieve the best results in their sport, striving for success at all costs; even though they are aware that there are potential health risks.[17] it has previously been seen that 33% of runners using analgesics, used these to aid recovery from a running injury and facilitate continued participation, showing that runners participate in high-risk behaviours for their sport.[7] this behaviour could also be related to the influence of the community around the runner and how they affect and shape attitudes and behaviours.[18] it is further supported by the data that membership of a sports club is predictive of selfmedication. [19] these are important considerations when attempting to promote safe analgesic practice in runners. eighty percent of participants disagreed with the statement that runners are sufficiently educated regarding the effects and side-effects of analgesics. this is a very important finding as it highlights the need for further input and education of runners, coaches, and running clubs regarding safe and appropriate analgesic use. inconsistency existed in the combined knowledge and attitudes scores of participants as most participants scored poorly in the knowledge section of the questionnaire but well in the attitudes section. this is an interesting finding as participants’ knowledge regarding analgesic use could be expected to influence their attitudes towards use, which was not the case. limitations and recommendations as the questionnaire was only available in english, it may have reduced the generalisability of the results of our study to a wider population. the fact that the questionnaire was only available online is a further limitation as the participants may not be representative of a lower socioeconomic group that may display different knowledge and attitudes to the participants in our study. their potential lack of participation, would more likely be due to the high mobile data costs in south africa, that runners from a lower socioeconomic grouping may not be able to afford, rather than a lack of access to the internet.[20] as the study questionnaire relied solely on self-reported data, which could not be independently verified, this may have biased the results due to recall bias. the ways that runners are educated regarding the safe use of analgesics, nsaids specifically, should be further investigated to determine the best means to address the high usage of nsaids, including combination analgesics, highlighted by our findings. the roles of social media, running clubs, and various media sources should be explored as the need for a formal education campaign amongst runners is evident. conclusion our study looked at the specific knowledge and attitudes of table 5. knowledge and attitudes towards running-related analgesic use. analgesic use in running χ 2 p odds ratio (95% ci) no (n=120) yes (n=212) total (n=332) knowledge scores inadequate knowledge (<75) 97 (81%) 170 (80%) 267 (80%) 0.02 0.89 1.04 (0.59 1.84) adequate knowledge (>75) 23 (19%) 42 (20%) 65 (20%) attitude scores negative attitude (<75) 19 (17%) 67 (32%) 86 (27%) 8.56 0.003** 2.3 (1.31 4.11)** positive attitude (>75) 94 (83%) 143 (68%) 237 (73%) combined knowledge (k) and attitude (a) scores inadequate k and negative a 17 (15%) 53 (25%) 70 (22%) 9.64 0.022* inadequate k and positive a 73 (65%) 115 (55%) 188 (58%) adequate k and negative a 2 (2%) 14 (7%) 16 (5%) adequate k and positive a 21 (19%) 28 (13%) 49 (15%) data are expressed as number (n) and percentage of respondents (%). ci, confidence intervals; ** indicates p<0.01; * indicates p<0.05. total column n values of <332 for participants are as a result of partially completed questionnaires. original research sajsm vol. 34 no.1 2022 6 runners towards analgesic use and has revealed important gaps in the specific knowledge and attitudes of runners towards analgesic use. despite our participants displaying positive attitudes towards the use of analgesics in relation to running, they had inadequate knowledge. hence these positive attitudes did not translate into safe practice as can be seen by the numbers of analgesic users and their patterns of use to continue participation despite pain or injury. the high usage of analgesics together with inadequate knowledge of their potential adverse effects increases the likelihood of severe complications during training and competition. this study highlights the urgent need to educate runners about the negative effects of analgesic use, either before, after or during training and competition. all stakeholders involved in providing information around analgesic use, both officially and unofficially, as well as pharmacists who dispense otc analgesia should be targeted in an education campaign to improve runners’ analgesic knowledge and their safe use in training and competition. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: rt designed the questionnaire, performed statistical analyses and drafted the manuscript. mb contributed to the study conception and design of the questionnaire and helped draft the manuscript. ht assisted with the structure, drafting and editing of the final manuscript. tb contributed to the study conception and design of the questionnaire, helped draft the manuscript and assisted with statistical analyses. all authors approved the final manuscript. references 1. hindley d. “more than just a run in the park”: an exploration of parkrun as a shared leisure space. leis sci 2020; 42(1):85–105. 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[https://doi.org/10.1007/s12325-016-0426-2] [pmid: 27796913] 20. van zyl g. data prices: how sa compares to the rest of the world. 2016 [cited 2017 feb 22]; available from: http://www.fin24.com/tech/multimedia/data-prices-how-sacompares-to-the-rest-of-the-world-20160930 https://runrepeat.com/state-of-running https://runrepeat.com/state-of-running http://dx.doi.org/10.1186/s40621-017-0124-9 http://dx.doi.org/10.7196%2fsamj.2021.%20v111i4.14635 http://dx.doi.org/10.7196%2fsamj.2021.%20v111i4.14635 http://dx.doi.org/10.1136/bjsports-2013-092558.20 http://dx.doi.org/10.1136/bjsports-2013-092558.20 http://www.ncbi.nlm.nih.gov/pubmed/24790506 http://www.ncbi.nlm.nih.gov/pubmed/24790506 http://www.fin24.com/tech/multimedia/data-prices-how-sa-compares-to-the-rest-of-the-world-20160930 http://www.fin24.com/tech/multimedia/data-prices-how-sa-compares-to-the-rest-of-the-world-20160930 original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license heat shock protein response during fixed intensity and self-paced exercise in the heat in young, healthy women on oral contraceptives compared with young healthy men k j onus, phd; j cannon, phd; f e marino, phd school of allied health, exercise and sport sciences, charles sturt university, panorama ave, bathurst, nsw 2795, australia corresponding author: f e marino (fmarino@csu.edu.au) heat shock proteins (hsps) are a group of highly conserved proteins which are present in the cells of all living organisms and they respond to a variety of physiological and environmental stressors. [1] hsps serve as molecular chaperones and accelerate cellular repair from heat stress, ischemia and endotoxic shock. [2] temperature is an important stimulus which contributes to the reported exercise-induced increase in hsps.[3] heat stress during exercise presents both thermal and sympathetic challenges, with increases in physiological strain compared with moderate temperature conditions [4], although it appears that the hsp response is exercise duration and intensity dependent.[5] further, the exercise stress response appears to be mediated by sex hormones [6], although the mechanism is not clearly understood. in female rats, exercise-induced elevations in hsp70 is negatively correlated with circulating oestrogen immediately before exercise.[7] rats treated with oestrogen regulate at a lower core temperature (tc) during heat exposure with increased evaporated water loss at all levels of tc, and with a decreased tc threshold at the onset of saliva spreading.[8] progesterone is known to elicit a thermogenic effect, raising female tc in the luteal phase (lp) of the menstrual cycle by ~0.5°c. [9–11] for women of reproductive age, menstruation is divided into two main phases, each governed by synthesis and the release of pituitary and ovarian hormones. the follicular phase (fp) occurs during approximately the first 14 d of a 28 d cycle and is characterised initially by low levels of oestrogen, progesterone, follicle-stimulating hormone (fsh) and lutenising hormone (lh).[7] as fp progresses from 1-14 d, circulating levels of lh and oestrogen gradually increase, stimulating the release of a mature oocyte from an ovarian follicle, termed ovulation, after which the luteal phase begins. [12] if fertilisation does not occur during this second phase when progesterone concentrations are highest for 7-10 days (d), the progesterone and oestrogen levels begin to decline, providing the stimulus for uterine shedding (menstruation) and the beginning of the cycle from day one. [12] the monophasic oral contraceptive pill (oc) is a formulation of exogenous hormones providing low doses of progesterone and oestrogen for 21 d (active phase) and a ‘withdrawal’ phase of seven d of sugar pills, which is the inactive phase. [13] [14] there is no consensus and little evidence exists regarding the combined effects of oc on exercise performance during heat stress and the production of cellular chaperones. exercise duration and intensity, combined with an elevated tc, are likely precursors for the appearance of cellular chaperones. we are unaware of any studies examining the combined effects of oc use, prolonged self-paced exercise and the appearance of circulating hsp. therefore the aim of this study was to determine the heat shock protein response (hsp72) during fixed intensity and selfpaced exercise in the heat in young, healthy women on oral contraceptives compared with young healthy men. methods participants and study design sixteen healthy and physically active participants (males n=8; mean±sd; age 22.1±5.3 yrs; mass 74.2±5.1 kg; height 1.78±0.03 m; peak oxygen consumption (vo2peak) 3.9±0.7 l·min-1) and females (n=8; mean±sd; age 20.9±2.9 yrs; mass 67.9±12.4 kg; height 1.63±0.06 m; vo2peak 2.3±0.42 l·min-1) gave written informed consent to participate in the study, which was background: heat shock proteins respond to a variety of physiological and environmental stresses, including heat stress, ischemia and endotoxic shock. hormonal changes during the female menstrual cycle can have a thermogenic effect on body temperature. the monophasic oral contraceptive (oc) pill provides low doses of progesterone and oestrogen over the course of the normal menstrual phase. there is little evidence regarding the combined effects of oc on exercise performance and heat stress with respect to heat shock protein response. objectives: this study aimed to determine the response of heat shock proteins (hsp72) during fixed-intensity and selfpaced exercise in the heat in young, healthy women on oral contraceptives compared with young healthy men. methods: sixteen physically active men and women performed 30 min fixed-intensity cycling at 50% of maximum workload, followed by 30 min of a self-paced time trial (tt) interspersed by 30 s maximal sprint at 9, 19 and 29 min respectively. trials were undertaken in cool (20°c; 48±3% relative humidity (rh)) and warm (32°c; 66±2% rh) ambient conditions. core (tc) and skin temperature, heart rate (hr) and subjective responses were measured before, during and post exercise. results: the distance, mean and peak power output, mean and peak speed during the self-paced time trial showed no difference between the ambient temperatures for men and women. hsp72 in females was higher than males at all sample points at both 20°c and 32°c, except for pre-exercise at 20°c (p< 0.04). women also attained a higher tc than men at the end of the tt in the heat (38.5°c v 37.9°c for women and men, respectively; p<0.03), higher mean hr and perceived exertion. conclusion: this study indicates that females who use oral contraceptives (oc) had higher levels of hsp72 than males when tested under the same environmental conditions. keywords: cellular stress, females, hsp, performance, thermoregulation s afr j sports med 2022;34:1-7. doi: 10.17159/2078-516x/2022/v34i1a11757 mailto:fmarino@csu.edu.au http://dx.doi.org/10.17159/2078-516x/2022/v34i1a11757 https://orcid.org/0000-0001-8352-6208 https://orcid.org/0000-0002-6495-2102 https://orcid.org/0000-0002-1540-8856 original research sajsm vol. 34 no.1 2022 2 approved by the institutional ethics in human research committee, charles stuart university. before starting the experimental trials, all participants were required to make an appointment with a physician and be cleared as healthy and able to undertake the experimental protocol. participants were non-smokers, physically active for at least one-h, three times per week, not acclimatised to exercising in the heat and free from injury. female participants had been taking a monophasic oc (levlen 28; 30 µg ethinyloestradiol and 150 mg levonorgestrel and brenda-35 ed; 35 µg ethinyloestradiol and 2 mg cyproterone acetate) for at least six months prior to testing. all males were free of pharmacological intervention. each participant completed two tests, one each in a moderate (20°c) and warm (32°c) environment respectively. the females were tested during the active pill phase of the oc cycle to control for potential effects from fluctuations of natural sex hormones. participants reported to the laboratory on three separate occasions to control for diurnal variations. the first visit was for familiarisation with the equipment and study conditions and to obtain a measure of vo2peak. the remaining laboratory sessions were identical and conducted in either a warm ambient temperature of 32°c or a moderate ambient temperature of 20°c, which were completed in a randomised/counterbalanced order to control for any changes in reproductive hormones throughout testing. women were tested during the active pill phase to ensure that they received a similar amount of synthetic oestrogen and progesterone derivatives each day. as such, women taking oc do not experience the follicular and luteal phases of the natural menstrual cycle due to ‘active’ hormones action [15]. testing sessions were conducted on day eight with exercise in 20°c (f20) and day 18 of taking hormone pills with exercise in 32°c (f32). these days were chosen for testing as day eight represents the part of the menstrual cycle when the body temperature will be normal, whereas day 18 would normally be when the body temperature is higher but is normalised due to the active phase of oc.[16, 17] males were tested in both moderate and warm conditions separated by at least seven days. participants refrained from exercise, alcohol or caffeine consumption for 12 h preceding testing. a 24 h food diary was maintained for the day prior to the first test so that individuals could follow similar eating patterns immediately prior to the remaining tests. nude mass was measured to the nearest 10 g after avoiding food and a venous cannula was introduced into a superficial forearm vein for repeated blood sampling. thermistors were attached to the skin. peak testing and performance protocol the vo2peak test was conducted as previously described. [16] four hours prior to reporting to the laboratory, participants ingested a telemetry pill (vital sense®, mini mitter company inc., usa) for the measurement of tc, recorded at five min intervals. skin thermistors were fastened to four sites as previously described and a mean skin temperature (ts) [18] was calculated at five min intervals. cycle testing was performed with the same apparatus used during the vo2peak test, with data recorded by means of fortius software for cosmos ergometer (v1.29, tacx bv, netherlands). to distinguish between physiological responses which occur during fixed intensity versus self-paced exercise, the endurance test was split into 2 x 30 min sections [19] [20]; 30 min of fixed intensity followed by 30 min of self-paced exercise. participants commenced the 30 min fixed-intensity cycling at 50% workload maximum (wmax) calculated from the vo2peak test programmed at the beginning of each trial using fortius software to ensure that fixed intensity was maintained and with gear settings kept constant throughout. subsequently, a three min rest was provided in the climate chamber to allow for blood collection. immediately following the rest period, a 30 min self-paced time trial (tt) commenced. during the fixed intensity and tt a series of ‘all out’ 30 s sprints were completed at 9, 19 and 29 min marks respectively. the participant was instructed to cycle as far as possible in the 30 min tt but was permitted to change gears as desired. no feedback was provided to the participant during any part of the trial other than a countdown to the next sprint given at two min, 30 s and 10 s intervals respectively, with strong verbal encouragement provided. upon the completion of the tt, blood samples were collected before the participant exited the climate chamber. a final nude body mass was recorded to estimate total body sweating. distance covered in km, average and peak cadence in rpm, average and peak speed in km.h-1 and average and peak power (w) were recorded by means of the tacx software at five min intervals throughout the cycling protocol. physiological and subjective measures a rating of perceived exertion (rpe; 1-10 scale) [22] and thermal sensation on a scale from one representing ‘cold’ to seven representing ‘hot’ [23] were recorded at five min intervals from the start to completion of the final sprint. heart rate was continuously monitored and recorded at five min intervals (fs1; polar electro oy, kempele, finland). feedback was not available to participants, with the receiver obscured from the participant’s view. blood samples were drawn from a superficial forearm vein immediately following the cannula set-up, following the fixed intensity protocol and upon completion of the tt. catheter patency was maintained by flushing with 0.9% sodium chloride (pfizer, australia) after each blood draw and ~ at five min intervals. blood samples were divided into pre-cooled serum separator tubes for the determination of heat shock protein 72 (hsp72). to examine the potential effect of exercise and heat stress on hormonal stress response [24], a sample was allocated to a pre-cooled k3edta tube for determination of cortisol (vacutainer, s-monovette, sarstedt, germany) to evaluate the metabolic intensity of exercise a 0.5 ml aliquot of whole blood was drawn into a syringe for determination of lactate (la-) (abl800 flex radiometer, copenhagen). collected blood was centrifuged at 4 500 rpm in a refrigerated centrifuge for 10 min. separated plasma was placed into one ml aliquots and frozen at -80°c until further analysis. before the analysis of hsp72, the serum was thawed to room temperature and mixed gently via inversion. duplicate plasma hsp72 concentrations were measured using an elisa kit (antioriginal research 3 sajsm vol. 34 no.1 2022 human hsp70 (total) elisa kit, assay designs inc., ann arbor, mi, usa), with detection limits of 31.25 ng.ml-1. to avoid inter-assay variations, all samples were assayed in the same assay run. serum protein concentrations were not corrected for plasma volume shifts, thus all statistical analyses were performed on actual measured circulating concentrations. [14] statistical analysis a priori power calculations were conducted using g*power (g*power 3.1.2, franz faul, germany), which indicated eight participants were needed. repeated measures anovas were used to determine differences between environmental and oc conditions in cycling performance or biochemical markers. when interactions or main effects achieved statistical significance, tukey’s hsd post hoc test was used to identify differences between means. statistical significance was set at p<0.05. data are reported as mean±sd. results exercise performance table 1 provides the various parameters measured during both fixed intensity and self-paced trials for each condition. for the fixed intensity bout, distance cycled, mean and peak power output and the mean and maximal speed did not differ for either gender or between ambient conditions. cycling speed during the sprints was significantly faster compared to the mean speed by ~27 km·h-1 in both f20 and f32 (p<0.001) and ~33 km·h-1 in both m20 and m32 (p<0.001), respectively. for the self-paced bout, distance cycled, mean and peak power output and mean and maximal speed did not differ between ambient temperatures for the respective genders. however, table 1. fixed-intensity and self-paced cycling performance measures fixed intensity time trial f20 f32 m20 m32 f20 f32 m20 m32 total distance (km) 15.7 ± 3.7 15.9 ± 3.1 16.8 ± 3.2 17.0 ± 2.9 10.8 ± 1.2 10.9 ± 1.1 13.0 ± 1.8 13.1 ± 2.6 mean power output (w) 116 ± 20 116 ± 20 155 ± 23 155 ± 23 126 ± 16 128 ± 15 189 ± 48 187 ± 65 peak power output sprints (w) 116 ± 20 116 ± 20 155 ± 23 155 ± 23 350 ± 98# 365 ± 65# 611 ± 76# 609 ± 113# mean speed (km.h-1) 30.9 ± 7.2 31.1 ± 6.0 33.8 ± 6.0 32.9 ± 5.8 21.2 ± 2.4 21.4 ± 1.9 24.5 ± 4.0 22.9 ± 5.1 max speed sprints (km.h-1) 57.7 ± 3.4* 57.8 ± 6.0* 66.3 ± 1.0* 66.4 ± 1.4* 34.2 ± 3.5* 40.9 ± 7.0*^ 46.8 ± 5.4* 49.5 ± 7.9* data expressed as mean ± sd. f, female (n=8); m, male (n=8); 20 and 32 are 20°c and 32°c ambient temperatures, respectively. * indicates p<0.05 where maximal speed is higher than mean speed in all conditions. # indicates p<0.05 where peak power output is higher than mean power output in all conditions. ^ indicates p<0.05 where peak speed is higher in f32 compared with f20. fig. 1. mean skin temperature (ts; top panel) and core temperature (tc; bottom panel) response during fixed-intensity (0 30 min) and self-paced time trial performance (35 65 min). f, female (n=8); m, male (n=8); 20 and 32 are 20°c and 32°c ambient temperatures, respectively. § indicates p < 0.05 compared with f20 and m20. ‡ indicates p < 0.05 compared with f20 and m20 and between m32 and f32 values; * indicates p < 0.05 from pre-exercise in m20 and m32; # indicates p < 0.05 from pre-exercise in f20 and f32; † indicates p < 0.05 between m20 and f20. original research sajsm vol. 34 no.1 2022 4 maximal speed was about seven km·h-1faster in f32 compared with f20 (p<0.007). in addition, maximal speed and peak power outputs were significantly greater than the mean speed and power outputs in all conditions (p<0.05). thermoregulatory responses the tc responses to exercise are shown in figure 1. in the fixed intensity section, tc was significantly elevated from baseline at 10 and 15 min of exercise for males and females respectively (p<0.05). time trials in both conditions did not result in a significant change in tc between males and females, although a trend from 20 min onwards for a higher tc in f32 compared with m32 and at the completion of cycling in 20°c between males and females was evident. self-paced cycling at 32°c resulted in significantly higher tc in females compared with males at all time points from the commencement of the self-paced cycling (p<0.03). in 20°c, females exercised with higher tc than males at a 20 min period until the completion of exercise (p<0.05). during the cycling exercise, ts was significantly elevated from baseline by 10 min in all conditions, until the completion of exercise (p<0.05). the ts at 32°c was higher than that reached during 20°c, for both males and females (p<0.05). at 32°c, males reached 35.7°c and females reached 35.9°c, whereas at 20°c males reached 31.8°c and females 29.6°c. heart rate and subjective responses table 2 lists the mean hr and rpe responses for each of the low intensity and sprint sections of the trials in each ambient condition. heart rate was significantly elevated from baseline, ~93 bpm and ~86 bpm for males and females respectively, in all conditions (p<0.05), and all sprint values were higher than mean values. the mean hr during fixed intensity cycling were similar for males and females but were higher during the non-sprint periods. throughout the time trial, mean hr for males and females, compared with lower intensity periods was higher. the hr responses were not statistically significant between males and females in either condition. rpe responses followed that of hr, in that rpe significantly increased from baseline and was elevated immediately following the sprints, and then significantly decreased in the lower intensity period (p<0.05). mean rpe was significantly higher for the sprints in each trial compared with the low intensity efforts. mean rpe was higher at the 32°c condition compared with that at the20°c for both males and females. however, there were no differences between males and females in the same ambient conditions. thermal sensation was significantly higher in the 32°c trial compared with the 20°c trial at all time points, for both genders (p < 0.05). however, there were no differences between males and females in the same ambient conditions. hsp responses figure 2 shows the hsp72 response at the three time points of collection. hsp in females was higher than males at all corresponding sample points for both 20°c and 32°c (p< 0.05) conditions. there were no differences within each condition for males or females. for cortisol, m32 increased significantly by the completion of the self-paced exercise, compared with the pre-exercise and fixed-intensity cycling (334, 357 and 514 nmol·l-1, for pre-exercise, fixed-intensity and self-paced exercise, respectively; p<0.04). lactate samples in all conditions increased from pre-exercise and are shown in figure 2. lactate was not significantly different among genders, ambient temperature or fixed-intensity versus self-paced cycling exercise. both genders reached ~9.1 nmol·l-1 at the completion of fixed-intensity cycling and ~8.8 nmol·l-1 at the completion of the self-paced cycling. discussion to the best of our knowledge, this is the first study to report the hsp response during cycling exercise performed in different ambient conditions in females using oc in comparison to untreated males. we observed that females exercising in both moderate and warm ambient conditions had a significantly higher hsp72 response compared with the men exercising in the same environments. the reason for this elevated response is not entirely clear; however, it is plausible that this response may be attributed to the elevated heat strain experienced by females as shown in figure 1. females exercised at a higher tc than males, although this difference was not significant until 30 min of f20 fixed-intensity and from the beginning of the tt in f32. the difference in tc value was approximately 0.5°c at the completion of both cycling bouts, which aligns with reports that females in the luteal phase of the menstrual cycle experience an elevation in tc of 0.3 0.5°c, due to elevated circulating table 2. heart rate (hr) and rating of perceived exertion (rpe) during the low intensity effort and sprints in fixed intensity and self-paced trials. intensity f20 f32 m20 m32 fixed-intensity low hr (bpm) rpe (au) 140 ± 6 3.7 ± 1.3 140 ± 11 3.6 ± 1.6 130 ± 9 3.1 ± 1.1 132 ± 10 3.3 ± 1.2 sprints hr (bpm) rpe (au) 171 ± 2* 5.3 ± 1.7* 173 ± 10* 5.6 ± 2.1* 172 ± 1* 6.0 ± 0.6* 173 ± 6* 6.1 ± 1.1* self-paced low hr (bpm) rpe (au) 150 ± 3 5.7 ± 1.6# 163 ± 1 6.7 ± 1.8 143 ± 2 4.0 ± 0.3 148 ± 1 5.0 ± 0.8§ sprints hr (bpm) rpe (au) 175 ± 3* 7.3 ± 1.2* 179 ± 1* 8.1 ± 1.5*§ 174 ± 1* 7.1 ± 0.4* 175 ± 1* 7.8 ± 0.5* data expressed as mean ± sd. f, female (n=8); m, male (n=8); 20 and 32 are 20°c and 32°c ambient temperatures, respectively; hr, heart rate; rpe, rating of perceived exertion; bpm, beats per minute; au, arbitrary unit. low and sprints are the intensities during the fixed intensity and self-paced sections of the trials in each ambient temperature. * indicates p < 0.05 increase from low to high intensity efforts in all conditions; § indicates p < 0.05 between ambient conditions for each gender; # indicates p < 0.05 increase compared with the male mean value in same ambient condition. original research 5 sajsm vol. 34 no.1 2022 progesterone. [10] previously, it has been shown in animal studies that body temperature elevation during exercise is important for the induction of exercise increases of hsp72 [3]. in human studies it appears that men and women differ in their cellular stress response, where men up-regulated their hsp72 response after a single bout of exercise in the heat, persisting for 12 days which confers cellular thermotolerance [6]. however, this upregulation appears highly dependent on the level of exercise-induced hyperthermia that is achieved after one bout of exercise, and, as shown in the present study, this was lower for males than for females. an additional factor which may explain the difference in the hsp72 response is that the women in the present study did not experience the fluctuations of the natural menstrual cycle as they were ingesting a monophasic oc formulation. this provides a steady, albeit low dose of oestrogen and progesterone over 21 days before the withdrawal phase. since oestrogen might mediate the stress response by stabilising cell membranes, oc use may interfere with this mechanism by reducing the natural oestrogen levels; thereby augmenting the need for upregulating hsp72 during acute stress. [6] presumably, women on oc are free of the day-to-day variations in body temperature which is characteristic of natural ovulatory cycles. however, synthetic hormones interfere with thermoregulation, elevating the body temperature consistently over 24 h, to the same extent as it is in ovulating women in the lp. [11, 25] although not statistically different, during fixed-intensity cycling the distance covered in 30 min was 7% further for males compared with females. the fixed-intensity power output was ~25% higher for males and they were also able to produce higher mean and maximal speeds (~8% and ~13% increases, respectively). although there were no statistically significant differences in the self-paced exercise, males cycled ~16% further than females (13.0 km compared with 10.9 km) and produced significantly higher mean (~32% increase) and peak (~42% increase) power output and mean (~11% increase) and peak (~21% increase) speed in both conditions. despite the higher intensity that males were able to maintain during the cycling exercise, there was no difference in thermal sensation and in fact, females sustained higher hr, rpe and tc than their male counterparts. the increased tc in females in this study could potentially explain the higher values of hsp72 compared to males. hsp72 for female fig. 2. heat shock protein (hsp; top panel), cortisol (middle panel) and lactate (bottom panel) responses pre-exercise (pre-ex), end of the 30 min fixed intensity cycle (post-30 min) and at the end of the 30 min time trial (post tt). f, female (n=8); m, male (n=8); 20 and 32 are 20°c and 32°c ambient temperatures, respectively. * indicates p < 0.04 from pre-exercise in m20 and m32; # indicates p < 0.04 for m32 at post tt compared with pre-ex; a indicates p < 0.01 vs pre-ex in both genders across all conditions. . original research sajsm vol. 34 no.1 2022 6 participants was higher at rest, and significantly elevated at the completion of the fixed-intensity cycling and at the completion of the self-paced cycling compared to males (~49% higher at all time points). there was no statistical difference between ambient temperatures, although in the f32 condition, the hsp72 concentration was higher than in the f20 condition. however, the hsp72 response was not reflective of circulating cortisol as only m32 produced significant increases during the self-paced cycling. although all other conditions demonstrated elevations in cortisol, these differences were not significant. thus, it is likely that the elevation in hsp72 is unrelated to the stress response to exercising in the heat. it is also possible that changes in cortisol and hsp72 were not completely developed over the course of the study’s exercise bout, as it is purported that the cellular chaperone response is duration and intensity-dependent. [11] thus, it is possible that the cycling exercise used here was insufficient to induce high levels of cellular stress. further, it is possible that the self-paced exercise allowed the participants to adjust their efforts to preserve homeostasis as much as possible. [26, 27] further explanations about the differences in hsp response in the present study include differences in muscle mass and body composition, surface area to volume ratio, sweat rate and biomechanical efficiency, none of which were examined here. prospective research could examine these differences in conjunction with longer, possibly more intense cycling exercise. finally, there are several limitations which limit the interpretation of our results. first, we did not directly compare normally ovulating females not taking oc with either females taking oc or compared to males. we limited our study to the role of oc use within females over the regular menstrual cycle. as such, the hsp72 response to exercise in females not taking oc is unknown. therefore, we cannot conclude that taking oc has any impact on the hsp72 response to exercise. all that we can conclude is that the hsp72 response in females taking oc was higher in both warm and moderate conditions compared with males exercising under similar conditions. we also cannot account for individual diurnal variation in the timing/phases of the menstrual cycle, thus we may not have completed testing precisely on the appropriate cycle day for each participant when tc might have been highest if they were not taking oc. conclusion this study indicates that females who use an oc had higher levels of hsp72 than males when tested under the same environmental conditions. the definitive reasons for this are currently unclear although females achieved a higher tc at the completion of the self-paced cycling, which, combined with the low dose of oestrogen and progesterone from the oc pill may have mediated the stress response by stabilising the cell membranes. further research is required to establish the mechanisms involved in the hsp72 response to self-paced cycling in the heat and whether there are consistent differences between males and females. conflict of interest and source of funding: the authors declare no conflict of interest. this study was supported in part by a csu postgraduate award to k. onus. author contributions: ko: study design, data collection, data and statistical analysis, manuscript draft and corrections (primary author). jc and fm: study design, data and statistical analysis, manuscript draft, corrections and review. references 1. kiang jg, tsokos gc. heat shock protein 70 kda: molecular biology, biochemistry, and physiology. pharmacol ther 1998; 80(2): 183-201. 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[doi: 10.1016/s1440-2440(00)80080-8][pmid: 11104310] 27. marino fe, lambert mi, noakes td. superior performance of african runners in warm humid but not in cool environmental conditions. j appl physiol (1985). 2004; 96(4): 124-130. [doi: 10.1152/japplphysiol.00582.2003] [pmid: 12949014] https://doi.org/10.1152/ajpregu.2000.279.4.r1316 https://doi.org/10.1016/j.jtherbio.2016.06.003 https://doi.org/10.1139/h95-003 https://doi.org/10.5271/sjweh.1815 https://doi.org/10.1152/japplphysiol.00582.2003 sajsm 595 (commentarty).indd short report 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license no time to waste: necessary health support for retired professional rugby players v gouttebarge,1,2,3 phd; dc janse van rensburg,2 md; gm kerkhoffs,1,3,4 phd 1 amsterdam umc, university of amsterdam, department of orthopaedic surgery, amsterdam movement sciences, meibergdreef 9, amsterdam, the netherlands 2 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 3 amsterdam collaboration on health & safety in sports (achss), amsterdam umc ioc research center of excellence, amsterdam, the netherlands 4 academic center for evidence-based sports medicine (aces), amsterdam, the netherlands corresponding author: v gouttebarge (v.gouttebarge@amsterdamumc.nl) transitioning out of professional sport is not an easy process, for example, athletes might face several challenges, such as adjusting to a new lifestyle, being suddenly ‘like everyone else’, and missing the sports atmosphere and competition. in addition, transitioning athletes might also face several health conditions affecting various spheres of the body and personality (e.g. musculoskeletal, psychological, neurocognitive). rugby union (hereafter referred to as ‘rugby’) has been associated with various post-career health conditions, such as osteoarthritis (oa) and mental health symptoms. as with other high-speed collision sports, professional rugby has been considerably under scrutiny when it comes to the long-term health of players. despite the growing body of scientific evidence and many recent anecdotal reports of retired players facing health challenges, support measures addressing the health of retired professional rugby players from a holistic perspective are not systematically implemented yet. neither is there any guidance for either the prevention of long-term health conditions or the promotion of their remission. the objective of this article is to reflect on the concept of long-term health in professional rugby and to introduce the after rugby career consultation (arcc) as a support measure for retired professional rugby players. health challenges after retirement from professional rugby scientific evidence shows that professional rugby players might be exposed to various health challenges after retirement from the game. oa is the most common rheumatic disease worldwide resulting in joint pain and activity limitations. in professional and well-trained rugby players, oa results from a complex interaction of biological, mechanical, and biochemical factors. in most cases it is precipitated by traumatic or overuse injuries that accelerate intra -articular pathological processes. consequently, retired professional rugby players may have an earlier onset and a higher prevalence of oa than the general population (matched for age and gender). for instance, two recent studies showed that the prevalence of ankle and hand oa in retired professional rugby players reached five percent (higher than that of the general population). ten percent of these retired players specifically reported hand pain.[1,2] mental health symptoms, defined as negative thoughts, feelings and/or behaviours, are also commonly reported following a professional rugby career. a study conducted on nearly 300 retired professional rugby players (mean age of 38 years) found prevalence rates ranging from 24% for alcohol misuse to 29% for sleep disturbances.[3] these prevalence rates are similar to those found among former elite athletes from other sports, but seem slightly higher than those found among the general population.[3,4] players forced to retire (e.g. due to a career ending injury) were more likely to report mental health symptoms in comparison to those that retired voluntarily. [5] when it comes to neurocognition, recent research has suggested an association between concussions during a sports career and long-term neurodegenerative conditions, such as dementia.[6] also, scientific evidence shows that retired professional rugby players are associated with small to moderate impairments in cognitive function (e.g. attention, memory, and concentration) when compared with agematched controls.[7] this is even more so among retired professional rugby players with a significant history of career related concussions. the health challenges likely to occur after a career in professional rugby are related to diverse health domains and thus warrant a holistic approach for the support of retired players. these health challenges also recognise that professional rugby stakeholders have a duty to care for retired players. duty of care in professional rugby as stated by the world health organization (who) and the international labour organization (ilo), ‘protection, promotion, surveillance and maintenance of the highest degree of physical, mental and social well-being of workers in all occupations long after they enter their retirement years’ is a fundamental human right that should be facilitated by social partners and stakeholders. logically, professional rugby there has been increasing scrutiny of professional rugby following the concern that retired players might face several negative health conditions. currently, support measures addressing the health of retired professional rugby players are not systematically implemented. this is unusual as professional rugby stakeholders have the duty of care to protect and promote the long-term health of retired players. professional football has a health programme for retired players that is implemented globally. this programme formed the basis for the after rugby career consultation (arcc) which was developed to empower the sustainable health and quality of life of retired professional rugby players. the arcc relies on information from three sources: (1) educational material, (2) medical examination, and (3) guidance, referral and/or monitoring. the south african rugby stakeholders have connected to pilot the arcc as there is no time to waste: a step towards necessary health support for retired professional rugby players is needed. keywords: rugby, transitioning, long-term health, health surveillance s afr j sports med 2021;33:1-3. doi: 10.17159/2078-516x/2021/v33i1a10651 mailto:v.gouttebarge@amsterdamumc.nl http://dx.doi.org/10.17159/2078-516x/2021/v33i1a10651 https://orcid.org/0000-0003-1058-6992 https://orcid.org/0000-0002-0126-4177 https://orcid.org/0000-0001-5916-7049 short report sajsm vol. 33 no. 1 2021 2 stakeholders have a duty to care, protect and promote the long-term health of retired players. in professional football, the concept of ‘exit health examination’ has been advanced, while the after career consultation was recently developed in order to empower the sustainable physical, mental and social health, and the quality of life of retired professional footballers.[8,9] during qualitative research conducted using questionnaires and semi-structured interviews among eight dutch retired professional footballers (mean age: 34 years; mean career duration: 13 years), the after career consultation revealed a number of medical conditions (e.g. heart rhythm disturbances, knee complaints with limited range of motion and signs of arthrosis) that triggered specific referral and/or guidance from medical practitioners. [9] even more so, the relevancy, suitability and added value of this support were positively evaluated by the retired professional footballers. [9] therefore, the after career consultation is globally implemented in the professional football industry by the fédération internationale de football association (fifa: governing body) and football players worldwide (fifpro: international players union). analogously to football, and because of the unequivocal duty of care stakeholders have towards retired players, support measures should also be developed and implemented in professional rugby. after rugby career consultation (arcc) based on scientific evidence and according to the needs of active and retired players, the arcc was developed to empower the sustainable health and quality of life of retired professional rugby players. the arcc relies on information from the following three sources: (1) educational material, (2) medical examination, and (3) guidance, referral or monitoring (if needed). the educational material consists of semi-medical information related to eight health domains that are relevant for players (e.g. detraining, injuries, oa, nutrition, mental health symptoms) and interviews with elite athletes who share their tips and tricks towards various challenges (including lifestyle). the educational material also includes information on how to prevent the occurrence or worsening of several health conditions in players. the medical examination is based on self-report measures (e.g. validated questionnaires for mental health symptoms), a thorough medical history (e.g. medication use, concussion history), a physical examination (e.g. blood pressure, clinical oa) and several assessments (e.g. standard resting 12-lead electrocardiogram, cognitive functions). the medical examination is based on a standardised protocol (box 1), ideally by a sports medicine physician with extended experience in professional rugby. based on all the information gathered, potential health challenges are then discussed with the players. depending on the findings from the medical examination, specific advice and/or guidance is provided. if needed, the retired professional rugby player might be referred for additional assessment(s) to a medical specialist (e.g. cardiologist, psychiatrist). in the two years following the medical examination, the health of the retired professional rugby player is monitored while potential additional needs are explored. there is no fixed post-career window to provide retired professional rugby players with the services of arcc some players might need support in the first months after they retire from professional rugby, while some others might be facing challenges later in their transitioning years. however, it is important to note that the arcc also acts preventatively in that it provides retired professional rugby players with educational material and advice on how to remain healthy, promoting a healthy lifestyle and the prevention of the occurrence or worsening of health conditions. th erefore, players who recently retired from professional rugby might be the primary target group rather than older players who might have already digested their transition out of the sport. rugby is a team sport and analogously, the professional rugby stakeholders within a given country should work together as a team to facilitate the arcc. piloting the arcc in south africa as with other high-speed collision sports, professional rugby has been increasingly under scrutiny when it comes to the long-term health of players. in order to contribute to the further development of their approach to this, the south african rugby union (saru) and the south african rugby legends association (sarla) have allied to pilot the arcc within the context of south african rugby. this will provide an insight into its feasibility and whether retired professional rugby players are satisfied with such a unique support measure. the hope is that such insight will guide future decisions in south africa as well as the possibility of implementing the arcc globally. there is no time to waste: a step towards necessary health support for retired professional rugby players is needed now. conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: vg conceptualised and drafted the manuscript. dcjvr and gmk reviewed the manuscript. all authors approved the final version of the manuscript. box 1. after rugby career consultation: overview of the medical examination characteristics age; marital situation; level of education; current study; number of studying hours; current employment; number of working hours; smoking status; lifestyle (e.g., level of physical activity, nutrition); health-related quality of life rugby history playing position; duration of rugby career; number of matches played; level of play; duration of retirement medical history hospitalisation; diseases; family history; medication use; musculoskeletal severe injuries; surgeries; concussions mental health symptoms anxiety; depression; sleep disturbance; alcohol misuse; drug misuse physical examination height; weight; body fat percentage; resting heart rate; blood pressure; pulmonary function; musculoskeletal status (e.g. range of motion of joints, signs of overuse tendon insertions, active and passive stability); clinical osteoarthritis additional assessments standard resting 12-lead electrocardiogram; cognitive functions (e.g. memory, attention) short report 3 sajsm vol. 33 no. 1 2021 references 1. jones me, davies ma, shah k, et al. the prevalence of hand and wrist osteoarthritis in elite former cricket and rugby union players. j sci med sport 2019; 22(8): 871-875. [doi: 10.1016/j.jsams.2019.03.004][pmid: 30940442] 2. paget da, aoki h, kemp s, et al. ankle osteoarthritis and its association with severe ankle injuries, ankle surgeries and health-related quality of life in recently retired professional male football and rugby players: a cross-sectional observational study. bmj open 2020; 10(6): e036775. [doi: 10.1136/bmjopen-2020-036775][pmid: 32565473] 3. gouttebarge v, kerkhoffs g, lambert m. prevalence and determinants of symptoms of common mental disorders in retired professional rugby union players. eur j sport sci 2016; 16(5): 595-602. [doi: 10.1080/17461391.2015.1086819] [pmid: 26419657] 4. gouttebarge v, castaldelli-maia jm, gorczynski p, et al. occurrence of mental health symptoms and disorders in current and former elite athletes: a systematic review and meta-analysis. br j sports med 2019; 53(11): 700-706. [doi: 10.1136/bjsports-2019-100671][pmid: 31097451] 5. brown jc, kerkhoffs g, lambert m, et al. forced retirement from professional rugby union is associated with symptoms of distress. int j sports med 2017; 38(8): 582-587. [doi: 10.1055/s-0043-103959][pmid: 28564743] 6. stewart w. sport associated dementia. bmj 2021; 372: n168. [doi: 10.1136/bmj.n168] 7. hume pa, theadom a, lewis gn, et al. a comparison of cognitive function in former rugby union players compared with former non-contact-sport players and the impact of concussion history. sports med 2017; 47(6): 1209-1220. [doi: 10.1007/s40279-016-0608-8][pmid: 27558141] 8. carmody s, jones c, malhotra a, et al. put out to pasture: what is our duty of care to the retiring professional footballer? promoting the concept of the 'exit health examination' (ehe). br j sports med 2019; 53(13): 788-789. [doi: 10.1136/bjsports-2017-098392][pmid: 29574450] 9. gouttebarge v, goedhart e, kerkhoffs g. empowering the health of retired professional footballers: the systematic development of an after career consultation and its feasibility. bmj open sport and exercise medicine 2018; 4(1): e000466. [doi: 10.1136/bmjsem-2018-000466] jsm0404pg000ed. sports medicine vol 16 no.1 2004 17 introduction satellite cells were first described by mauro in 1961.30 they form a distinct and separate population of undifferentiated, myogenic cells within all vertebrate skeletal muscle. these small cells, with a large nuclear to cytoplasmic ratio, are found sandwiched between the basal lamina and sarcolemma of each myofibre. they are distinct from the myonuclei of the multinucleate skeletal muscle fibre, which lie under both the basal lamina and the sarcolemma and which lose the capacity to undergo mitosis soon after birth. satellite cells are now known to be the cells involved in muscle development and growth,21 repair43 and regeneration after muscle injury19,22 and are implicated in the changes in muscle ageing.14 the number and distribution of satellite cells in a muscle are dependent on the species, age and muscle fibre type and in primates they comprise from 1% to 3% of the nuclei in adult skeletal muscle.14,42 they are not uniformly distributed throughout muscle and are more commonly found near capillaries, neuromuscular junctions and myonuclei.7,38,50 during normal muscle growth, quiescent satellite cells are reported to proliferate and fuse with their host myofibre.41,42 they may also be activated by exercise and muscle injury, causing a sequence of morphological transformations that is less well documented.38 repeated resistance training results in hypertrophy and is also associated with myofibre microtrauma that necessitates repair. in resistance exerciseinduced hypertrophy, repeated microtrauma leads to macrophage regulated cytokine activation of satellite cells. this results in the production and replacement of nuclear material and satellite cell proliferation, with migration by chemotaxis and fusion to existing fibres.5,36,39,41,42 mobilisation of satellite cells following microtrauma is reported as being of two forms sub-basal laminar migration to the damaged area if the integrity of the basal laminar is not disturbed, and migration to adjacent myofibres using tissue bridges if the basal lamina is disrupted.41,42,48 most reports describe the morphology of satellite cells in their quiescent state and as a uniform cell line.32 while it is generally held that satellite cells evolve from the multi-potential mesodermal cells of the embryonic somite,34,42 there is evidence to suggest that satellite cells may also be derived from endothelial cells or a common precursor. this and differential gene expression in quiescent satellite cells suggests that there may be more than one satellite cell line. these cell lines respond differently to activation and on any muscle fibre, some function as stem cells and others are available for fusion.42 a new population of adult skeletal muscle-derived, pluripotential stem cells called side population cells have recently been identified using a fluorescent dye exclusion, flowcytometric method. original research article mobilisation of satellite cells following ischaemia and reperfusion in primate skeletal muscle m a gregory (phd)1 m mars (mb chb, md)2 1electron microscope unit, university of kwazulu-natal, durban 2department of telehealth, nelson r mandela school of medicine, university of kwazulu-natal, durban correspondence: m mars department of telehealth nelson r mandela medical school private bag x7 congella 4013 kwazulu-natal tel: 031-260 4364 fax: 031-260 4455 e-mail: mars@nu.ac.za abstract objective. to describe the morphological and morphometric features of activated skeletal muscle satellite cells in primates, using an ischaemic reperfusion model. setting. the study was undertaken at the biomedical resource centre and the electron microscopy unit of the university of kwazulu-natal. interventions. eight vervet monkeys were anaesthetised and subjected to 3 hours of tourniquet-induced lower limb ischaemia. open muscle biopsies were taken from tibialis anterior muscle immediately after tourniquet release and 12, 24, 36 and 48 hours after tourniquet release. control biopsies were taken from the opposite limb. main outcome measures. description of the morphological and morphometric changes in satellite cells after activation, as seen on transmission electron microscopy. results. two distinct patterns of satellite cell activation are described. in group 1, the cytoplasm of the satellite cell expands around the myocyte and the gap between the satellite cell and the myocyte appears to break down, or in group 2, the novel observation of the satellite cell breaking away from the myofibre and becoming a myocyte totally encased in its own basal lamina. the satellite cells of group 1 were significantly longer than the group 2 cells (p = 0.018) and this was associated with a significant reduction in the percentage of nuclear to cell area (p = 0.011). conclusions. tourniquet-induced ischaemic reperfusion injury is shown to result in two distinct patterns of satellite cell activation which may represent different functions or subsets of satellite cells. these cells are a subpopulation of the satellite cell pool. in vitro cultures of side population cells have the ability to reconstitute lethally damaged bone marrow in vivo. in regenerating muscle, the number of myogenic precursors exceeds that of resident satellite cells and this implies migration or recruitment of undifferentiated progenitors from other sources.11,15,16,34,42 supporting this, cultured bone marrow cells have been shown to be able to differentiate into myoblasts under the appropriate stimuli.6,16 the role of satellite cells in the effects of ageing on skeletal muscle is also an area of growing recent interest.23 satellite cells in people over the age of 60 years have been shown to proliferate normally but to produce thinner and more fragile myotubes. theoretically every cell has the capacity to divide a finite number of times, in the region of 60 70 divisions. each division results in shortening of the telomeres, or ends of the chromosomes, and ultimately the telomeres reach a critical length, at which point the cell can no longer divide.22 of interest is whether years of training and associated satellite cell activation will lead to a premature reduction in the total number of satellite cells due to loss of the ability of satellite cells to divide and hasten muscle ageing. satellite cells also play a role in myopathies. in duchenne's muscular dystrophy, the myofibres are deficient in the cytoskeletal protein dystrophin. this renders them fragile and normal muscle contractions can lead to muscle damage and degeneration. this leads to satellite cell activation and the production of new myofibres that are also dystrophin deficient. eventually the satellite cell pool is depleted. in the mdx mouse model which lacks dystrophin, myoblasts (satellite cells) cultured in vitro have been successfully injected into pathological muscle to supplement defective satellite cells.6,25,28 this opens the possibility of supplementing satellite cell populations to both augment hypertrophy and to delay muscle ageing. skeletal muscle blood flow is not homogeneous throughout a contracting muscle. during both dynamic and isometric muscle contractions blood supply within the working muscle varies and localised areas of relative ischaemia may occur. there are no reports of the effect of ischaemic reperfusion injury on satellite cell activation. the existing models of muscle regeneration and satellite cell activation include gene knockout, muscle crush injury, chemically induced muscle injury and freezing injury. the aim of this study was to investigate the morphological changes in satellite cells using tourniquet-mediated ischaemic/reperfusion injury as a model. animals and methods eight adult vervet monkeys were studied. they were cared for according to the requirements of the national code for the use of animals in research and the study was undertaken with the approval of the ethics committees of the university of natal and the university of durban-westville. anaesthesia was induced with ketamine (15 mg/kg) by intramuscular injection and maintained with sodium thiopentone (25 mg/kg) intravenously, as necessary. the animals' temperature and blood pressure were monitored during anaesthesia. they were awakened after tourniquet release. subsequent muscle biopsies were performed after intramuscular administration of ketamine (15 mg/kg). a hind limb was exsanguinated using an esmarch bandage and a pneumatic tourniquet applied to the thigh at 100 mmhg above systolic pressure. the tourniquet was maintained for 3 hours. in 4 animals, open muscle biopsies were taken from the tibialis anterior muscle before tourniquet application and 6 hours, 24 hours and 48 hours after tourniquet release. in the remaining 4 animals, biopsies were taken before tourniquet application, and 12 hours and 36 hours after tourniquet deflation. the skin was sutured with 3/0 nylon after each biopsy. electron microscopy in order to exclude super-contraction artefact in myofibres, the tissue was desensitised to further mechanical trauma by immediate immersion in 0.1m cacodylate buffered karnovsky's fixative24 for 10 minutes. after desensitisation, the central artefact-free core of the biopsy specimen was removed as described by olmesdahl et al.33 and diced into 1 mm cubes before re-immersion in fixative for a further 1 hour. after postfixation/staining with 1% osmium tetroxide, the tissue was dehydrated through increasing concentrations of ethanol before being embedded in spurr epoxy resin.46 four 1 mm3 blocks of tissue were prepared from each specimen. sections, 1 µm thick, were cut off each block, stained with 1% alkaline toluidine blue and examined by light microscopy. using the 1 µm sections as indicators, the blocks were orientated so that myofibres could be cut in longitudinal section. ultrathin sections of approximately 60 nm were cut from each block using a diamond knife. to increase the surface area for examination and thereby improve the probability of satellite cell detection, ultrathin sections were obtained from five deeper levels (100 µm). ultrathin sections were mounted on copper grids and stained with 1% ethanolic uranyl acetate and reynolds lead citrate35 prior to examination with a jeol 1010 transmission electron microscope (tem). morphometry images of whole satellite cells were captured using a kodak megaplus slow-scan video camera and measurements made using an analysis 2.1, image analytical system. quiescent satellite cells in normal, untraumatised muscle have been reported to take up a position oblique to the long axis of the myofibre.1 as all bundles of myofibres had, as far as possible, been cut in longitudinal section, most satellite cells should have been cut in transverse transverse/oblique section. satellite cell length and width were measured, and satellite cell circularity, cell volume and nuclear volume were calculated. statistical analysis was by unpaired t-test with welch's correction when bartlett's test had shown a significant difference between standard deviations. analysis of variance was by the non-parametric kruskal-wallis test with dunn's multiple comparison test used for post hoc testing. results a careful light microscopic examination of the 1 µm sections was unable to unequivocally locate or identify satellite cells as independent entities in any specimen. satellite cells, therefore, were only identified by carefully examining ultrathin sections using the tem. even though five levels had been cut from each block, small block size and thinness of section, together with the normally sparse number of satellite cells in muscle tissue 18 sports medicine vol 16 no.1 2004 sports medicine vol 16 no.1 2004 19 resulted in very few ‘whole’, nucleated satellite cells being found in each specimen. while non-nucleated portions of satellite cells were found beneath the basal lamina of fibres in many sections, only 25 intact, nucleated satellite cells/myoblasts were found. in the absence of a classification system for satellite cells in various stages of activation, we have used their morphological features and morphometry to classify activated satellite cells/myoblasts into two groups. group 1 describes those cells in which the plasmalemma remained close to the sarcolemma of their host myofibre and which underwent marked changes in the ratio of nuclear to cell length. based on their shape and size, group 1 satellite cells were further subdivided into the following phases of activation: quiescent, early activation, and fully mobilised. group 2 describes cells that appeared to be separating from their host myocyte and were classed as being either in various phases of separation from their host myocyte or fully motile, interfibre myoblasts. group 1: quiescent satellite cells (n = 4), were present in control samples and in some specimens up to 12 hours after reperfusion. they averaged 6.5 µm in length, 2.9 µm in width and were generally oval in shape (circularity 0.47). they contained a large rounded/oval nucleus which occupied approximately 60% of the total transversely sectioned area of each cell (fig. 1). the plasmalemmae of quiescent satellite cells (sc) were separated from the sarcolemma of their host myocyte by a gap approximately 25 30 nm in width (fig. 2). no desmosomes joined the cells and no electron-dense material was present in the intercellular gap. the cytosol contained small mitochondria with distinct cristae, occasional golgi cisternae, α-glycogen particles, free ribosomes and strands of endoplasmic reticulum. chromatin, while dispersed throughout each nucleus, was especially aggregated beneath the nucleolemma. group 1: early activated satellite cells (n = 6) were found in specimens from 6 to 24 hours after reperfusion. the early phases of activation were characterised by either an elongation or reorientation (to the long axis of the fibre) of satellite cells (circularity 0.29). cells in this category ranged from 10 µm to 15 µm in length and averaged 3.4 µm in depth. while the average cross-sectional area of early mobilised (em) satellite cells had nearly doubled from 14.4 µm2 to 27.1 µm2,2,20 the proportion occupied by the nucleus was only marginally reduced from 60% to 55%. the plasmalemmae of the two cells remained approximately 30 nm apart. while satellite cell mitosis was not visualised, 2 of the 6 cells in this group contained centrioles (fig. 3). cytoplasmic organelles were morphologically similar to those quiescent cells. there was perhaps a little more clumping of chromatin in these cells. group 1: fully mobilised satellite cells (n = 7) were present in muscle from 12 to 48 hours after reperfusion. these cells ranged in length from 23 µm (fig. 4) to 60 µm in length (fig. 5) and averaged 2.8 µm in width (circularity 0.11). again, while the average cross-sectional area had nearly doubled from 27 µm2 to 51 µm2, the proportion occupied by the nucleus was only reduced by 5% 50%. in most cases, the cell plasmalemmae were separated by a gap of approximately 30 nm (fig. 6). in some instances, however, adjacent regions of satellite cell plasmalemma and sarcolemma appeared to have broken down with the cytosol-sarcosol of the two cells merging (fig. 7). fragments of the 2 plasmalemmae were still visible in places. centrioles were not present in extensively elongated cells. however, even in peripheral regions, the cytoplasm contained numerous mitochondria, well-developed golgi apparatus, numerous α-glycogen particles and free ribosomes, all features suggestive of high metabolic activity. group 2: these separating satellite cells (n = 6) were present in muscle from 6 to 24 hours after reperfusion. like quiescent cells, they tended to be oval and ranged in length from 5.1 µm to 9.5 µm and averaged 2.9 µm in width (circularity 0.38). the mean cross-sectional area of the separating cells was approximately 30% greater than that of the quiescent cells (19.3 µm2) and the average area occupied by nuclei was 6% greater (66%). while still contained within the basal lamina of host myofibres, separating satellite cells were all characterised by the presence of basal lamina between the satellite cell plasmalemma and fibre sarcolemma. fig. 8 shows what appears to be an ‘in-growth’ of the basal-lamina between a satellite cell and fibre with the satellite cell being separated from its host by a gap of 270 nm. in addition to all cells being separated from fig. 1. group 1 quiescent: transmission electron micrograph of a typical quiescent satellite cell from a control muscle biopsy. note the large, oval nucleus (n), sparse small mitochondria (m) and occasional lipid droplets (l) (my = skeletal myosite and arrow heads point at the basal lamina over the satellite cell surface). fig. 2. group 1 quiescent: transmission electron micrograph showing the detail of the separation between satellite cell (sc) plasmalemma and the myocyte sarcolemma (arrow-heads) in control muscle (er = endoplasmic reticulum of the satellite cell). 20 sports medicine vol 16 no.1 2004 their hosts, all separating satellite cells differed from quiescent cells in that they contained large irregularly shaped, bi-lobed nuclei containing aggregates of chromatin. while probably only a consequence of the plane of sectioning, the lobular shape of the nucleus in one satellite cell suggested that the cell had two nuclei (fig. 9). other cytoplasmic organelles were similar to those in quiescent cells. although retaining focal attachments to their host myofibre, separating satellite cells were characterised by extensive intercellular gaps often filled with whorls of membranous material (figs 9 and 10). in one instance, while still nestled within an indentation of a myofibre, a separating satellite cell was entirely encapsulated by basal lamina (fig. 11). this cell containing a clearly defined centriole had an irregularly shaped, bi-lobed nucleus with aggregates of chromatin at each pole. group 2: intercellular myoblasts (n = 2) were present in the specimens from 36 to 48 hours after reperfusion. they averaged 11.6 µm in length and 4.5 µm in width, with a circularity of 0.37. the mean cross-sectional area of the myoblasts was 37 µm2 and the average area occupied by nuclei was 54% (table i). these cells were encapsulated by a well defined fig. 4. group 1. mobilised, after 24 hours of reperfusion. transmission electron micrograph showing an elongated satellite cell (n = nucleus, my = skeletal myocyte). fig. 5. group 1 mobilised, after 36 hours of reperfusion. transmission electron micrograph showing a very elongated satellite cell. the arrow heads show the extent of the cell (c = capillary, e = endothelial cell). fig. 6. group 1 mobilised, after 36 hours of reperfusion. transmission electron micrograph showing detail of separation between satellite cells plasmalemma and the skeletal (my) myocyte sarcolemma (arrowheads). (g = golgi apparatus, m = mitochondria and arrows show the basal lamina.) fig. 3. group 1. early activation, after 12 hours of reperfusion. transmission electron micrograph showing elongating satellite cell. note the increase in mitochondria and cytoplasmic vesicles (ce = centriole; arrow heads show the basal lamina). fig. 7. group 1 mobilised, after 36 hours of reperfusion. transmission electron micrograph showing detail of the apparent fusion between the satellite cell (sc) and the skeletal myocyte (my). note the absence of sarcolemma/ plasmalemma, numerous coated vesicles and occasional whorls of membranous material (w). sports medicine vol 16 no.1 2004 21 basal lamina and contained a large, irregularly shaped nucleus (fig. 12). mitochondria and other cytoplasmic organelles were similar to those described in the mobilising satellite cells of group 1. satellite cell and nuclear length and breadth, cell circularity (expressed as the ratio of breadth/length, with 1 = a perfect circle), cross-sectional cell area, nuclear area and the ratio of nuclear to cell area expressed as a percentage for group 1 and group 2 are shown in table i. the satellite cells in group 1 were significantly longer than the group 2 cells and this was associated with a significant reduction in the percentage of nuclear to cell area. the mean data for each of the 5 developmental phases of satellite cells is shown in table ii and the data are summarised in fig. 13. analysis of variance (anova) with post hoc testing shows significant differences between quiescent cells and mobilised cells in group 1 for cell length (p < 0.001), circularity (p < 0.05), cell area (p < 0.05) and nuclear area (p < 0.05). mobilised group 1 satellite cells were also significantly longer (p < 0.01), and had a smaller percentage of nuclear to cellular area (p < 0.01) than separating group 2 cells. fig. 8. group 2 separating, after 24 hours of reperfusion. transmission electron micrograph showing separation of the satellite cell (sc) from the skeletal myocyte (my). note the basal lamina over the outer portion of the sc plasmalemma and over the entire surface of the myocyte sarcolemma (arrowheads). also note the apparent in-growth of basal lamina between the sc and the my (arrows). fig. 10. group 2 separating, after 24 hours of reperfusion. transmission electron micrograph showing detail of basal lamina both over the satellite cell (sc) and in between the sc and the myocyte (my) (arrowheads). note whorls of osmiophilic, membranous material between the cells (w). fig. 11. group 2 separating, after 12 hours of reperfusion. transmission electron micrograph showing bi-lobed satellite cell (sc) encapsulated by basal lamina and separated from the myosite (my). table i. cell length, width, circularity, area and nuclear area and the percentage of the nuclear to cell area (%n/c area) are shown as means and one standard deviation group 1 group 2 t-test number 17 8 p value cell length (µm) 17.9 + 13.7 8.9 + 2.2 0.018 cell width (µm) 3.0 + 1.0 3.3 + 0.8 0.579 circularity 0.3 + 0.2 0.4 + 0.1 0.106 cell area (µm2) 34.0 + 26.0 23.8 + 10.3 0.173 nuclear area (µm2) 17.4 + 11.2 14.5 + 4.9 0.364 %n/c area 54.4 + 7.2 62.9 + 6.8 0.011 fig. 9. group 2 separating, after 24 hours of reperfusion. transmission electron micrograph showing separation of the satellite cell (sc) from the myocyte (my). the basal lamina extends both over and between the two cells (arrowheads). note bi-lobed nucleus and large membranous whorls (w). 22 sports medicine vol 16 no.1 2004 discussion to date there are no reports of the effect of an ischaemic reperfusion injury on satellite cell activity. the sequential morphological changes occurring in skeletal myofibres after periods of ischaemia and up to 24 hours reperfusion are, however, well described.17,18 in brief, a small number of irreversibly injured fibres exhibit progressive pathomorphological changes that result in cell death. in most cases, however, the ischaemic reperfusion injury is reversible, being expressed morphologically in the form of intermyofibrillar and juxta-nuclear oedema, swollen sarcoplasmic reticulum and t-tubes, damaged and/or necrotic mitochondria, focal areas of z-band ‘streaming’, myofibrilysis and occasional internalised myonuclei. in other models, using crushing,27 freezing,9 or chemically induced injuries to skeletal muscle12 to study satellite cell activation, proliferation and regeneration, two response of satellite cells to activation have been described. these are based on the integrity of the basal lamina. there is general consensus that following load-induced hypertrophy and/or a focal reversible injury, where the basal lamina has not been ruptured, myofibre repair is achieved by the chemotactic migration of activated satellite cells beneath the basal lamina to the site of injury.36,42 satellite cell activation has been reported within 6 hours22 and mitosis is well underway within 24 hours of muscle overload or myotrauma.47 when in place, satellite cells are thought to fuse with the underlying myofibre, thereby participating in hypertrophic31 and repair processes.49 if the basal lamina is disrupted, satellite cells may move to adjacent myofibres by means of tissue bridges.40,48 while there is acceptance that satellite cells migrate to areas of need, changes in size, shape and ultrastructure during such migration are less well reported. satellite cell activation occurs in response to macrophagedependent cytokine stimuli. it is of interest that macrophages were not noted in either the light or em specimens. hormonal and growth factors are also known to influence muscle regeneration.2,20 various in vitro studies have been used to investigate and demonstrate the effects of hormones10 and ‘insulin-like’ (igf),21,29 hepatocyte (hgf),8 fibroblast (fgf)44 and cytokine table ii. cell length, width, circularity, area, nuclear area and percentage of nuclear area to cell area for the three stages of group 1 and two stages of group 2 expressed as means, one standard deviation and the range. the results of the anova and the results of post hoc testing are shown (* p < 0.05, † p < 0.01 and ‡ p < 0.001). cell cell cell nuclear % n/c stage n length (µm) width (µm) circularity area (µm2) area (µm2) area group 1 quiescent 4 6.5 + 1.1‡ 2.9 + 0.9 0.47 + 0.18* 14.4 + 5.2* 8.6 + 2.8* 60.5 + 5.2 range 5.7 8.0 1.7 3.8 0.21 0.60 7.4 19.8 5.0 11.6 56 68 early mobilised 6 12.1 + 1.5 3.4 + 1.2 0.29 + 0.12 27.1 + 11.1 14.8 + 5.4 55.3 + 6.2 range 10.2 14.3 1.9 4.9 0.13 0.43 18.4 46 8.9 22.5 48 64 mobilised 7 29.4 + 15†‡ 2.8 + 0.9 0.11 + 0.06* 51.3 + 32.1* 24.8 + 13.4* 50.1 + 6.8† range 15.0 60.0 1.6 3.9 0.06 0.21 24.9 105 11.7 43.5 41 60 group 2 separating 6 8.0 + 1.7† 2.9 + 0.6 0.38 + 0.14* 19.3 + 6.7 12.6 + 4.1 65.8 + 3.5† range 7.0 9.5 2.3 3.9 0.26 0.63 11.2 29.4 7.0 18 61 71 motile 2 11.6 + 0.2 4.3 + 0.8 0.37 + 0.06 37.4 + 5.4 20.0 + 0.3 54.0 + 7.1 range 11.4 11.7 3.7 4.8 0.32 0.41 33.6 41.2 19.8 20.2 49 59 anova (p-value) 0.0002 0.4380 0.0044 0.0053 0.3638 0.0105 fig. 12. group 2 motile myoblast, after 36 hours of reperfusion. transmission electron micrograph showing a myoblast in the intercellular space. note that the cell is encapsulated by basal lamina (arrowheads). l e n g th u m % n u c le u s t o c yt o p la s m a re a qq em m s my 70 60 50 40 30 20 10 0 satellite cells: stage of activation length % n/c area 60.5 6.5 13 54 34.6 51.4 8 11.6 54 65.8 fig. 13. bar graph showing the average satellite cell length and the nuclear to cytoplasmic ratio expressed as a percentage, for satellite cells in each of the 5 stages of activation (q = quiescent, em = early mobilised, m = mobilised, s = separating and my = motile). ‘transforming’ (tgf)37 growth factors on satellite cell proliferation and differentiation. in this study, we employed 3 hours of tourniquet-mediated ischaemia, and the subsequent additional injury caused by reperfusion, to follow the phases of satellite cell activation and mobilisation in vervet monkey skeletal muscle. the study is primarily concerned with graphically detailing the sequential changes that satellite cells undergo following muscle injury. we are aware that multiple muscle biopsy, per se, will almost certainly activate satellite cells. our results, therefore, may not exclusively represent the effect that the largely reversible ischaemic reperfusion injury has on both muscle and satellite cells but may include an additional irreversible injury caused by the mechanical trauma of multiple biopsy of adjacent muscle fibres. based on the different morphological and morphometric appearances of the satellite cells over time we have grouped the cells into those that appear to be migrating under the basal lamina and those that appear to be separating and migrating to adjacent myofibres. typically, quiescent satellite cells in mammalian skeletal muscle are reported to average 25 µm in length, 4 µm in height and 5 µm in width.1 with the exception of increased numbers near myoneural junctions and capillaries,26 they are thought to be evenly distributed along the length of the myofibre. satellite cells associated with tension-free myofibres are reported to be orientated obliquely to the long axis of the fibre.1 in this study, as all specimens were orientated to facilitate longitudinal sectioning, most satellite cells were probably transversely/obliquely sectioned. this appears to be the case, for most quiescent satellite cells did not exceed 4.5 µm in height and were not shorter than 5.2 µm in cross-sectional width. from 6 to 12 hours after reperfusion, some group 1 satellite cells were noted to have elongated. within 24 hours, their circularity had changed from 0.47 to 0.29 and average cell length had increased from 6.5 µm to 12.1 µm. whether such change in shape was a consequence of satellite cell elongation or reorientation of the satellite cells with regard the longitudinal axis of the myofibre, could not be determined from the two-dimensional images. however, 48 hours after reperfusion, circularity was reduced to 0.11, some cells were 60 µm in length and the average cross-sectional area of satellite cells had increased by 356%. taken sequentially these data appear to confirm the elongation of activated satellite cells for 48 hours after reperfusion, with activated satellite cells being orders of magnitude longer/larger than quiescent cells. they do, however, throw into question whether satellite cells do indeed migrate or simply expand through the inter-basal lamina/sarcolemmal space, over the fibre surface — rather like the white of an egg spreads when an egg is broken into a pan. irrespective of whether satellite cells migrate and/or expand over the fibre surface, from 36 hours after reperfusion, in some samples the opposing satellite cell plasmalemma and sarcolemma of the host fibre appeared to be incomplete. such fragmentation would enable the contents of the satellite cells to mix with the sarcosol of its host myofibre. the progressive changes in the morphological appearance of satellite cells comprising group 1, suggest that quiescent, early mobilised and mobilised satellite cells may be sequential phases in the remodelling of satellite cells in response to reversible myofibre injury. present theory suggests that following a more serious injury, where the basal lamina has been broken and myofibres may die, satellite cells associated with both healthy and injured myofibres proliferate and migrate to damaged areas.48 once in position, these satellite cells/presumptive myoblasts will either fuse with damaged myofibres to attempt repair, or fuse together to form a myotube, thereby replacing irreversibly injured and necrotic myofibre.5,8,22,45 the satellite cells that we have classified as group 2, or ‘separating’ satellite cells, are similar in many respects to quiescent cells in group 1. they are however characterised by the features of the breakdown of the satellite cell membrane and the sarcolemma interface with the apparent ‘in-growth’ and development of basal lamina between the satellite cell plasmalemma and sarcolemma of the host myofibre. in all cases, these cells, although contained within the basal lamina, appeared to be separating from their host myofibre. all separating satellite cells were found to be associated with apparently normal myofibres within 24 hours of reperfusion and their size and shape were similar to intercellular myoblasts. group 2 satellite cells could be a different subset of satellite cells whose role is migratory and whose purpose is the eventual genesis of new myofibres or repair at distant sites. there is considerable evidence to suggest that although quiescent satellite cells in different muscle types are morphologically similar, they may not represent a homogeneous cell line with unequivocally predictable, differentiative outcomes. it is well known that the size of satellite cell populations varies with type of muscle, with oxidative myofibres having larger numbers of satellite cells than glycolytic fibres.3,13 further, in culture medium, satellite cells from slow-twitch muscles have been shown to differentiate more quickly and fuse into more numerous myotubes than those from fast-twitch muscle.4 in addition, it has been suggested that a distinction may exist between satellite cells mobilised to effect repair and regeneration and those destined to maintain the progenitor pool of satellite cells for subsequent rounds of hypertrophy or regeneration.8 the disparate morphology of group 1 and 2 satellite cells in this study gives credence to a postulate that in addition to the above, satellite cells may also be divided into functional types whose activation and eventual differentiation is dependent on the nature and severity of muscle injury. most authors report that following activation, satellite cells proliferate — we found no direct evidence of mitosis. the separating satellite cells of group 2 did show features suggestive of mitotic activity. their nuclei tended to be multi-lobed, with condensed chromatin, a particularly high nucleus to cytoplasmic area ratio and in some instances, contained a well-defined centriole, all features suggestive of mitotic activity. as we did not observe more than one satellite cell at any site and as most separating satellite cells were observed within 12 hours of reperfusion, the cells are more likely to be preparing for division than to have already divided. these features may represent various degrees of cell division between prophase and anaphase and that following activation, satellite cells destined to divide become encapsulated with basal lamina prior to and perhaps during the process of division. in conclusion, this study describes the appearance of satellite cells in vervet monkey muscle at different times after ischaemic reperfusion muscle injury. two patterns of response are described. satellite cell function and anomalies, morphological, cytochemical and genetic, are the focus of research into reasons why dystrophic muscle continues to degenerate, sports medicine vol 16 no.1 2004 23 24 sports medicine vol 16 no.1 2004 why muscle hypertrophies and the effects of ageing on muscle. it is hoped that by characterising the variable appearance of satellite cells in normal muscle, the data can be used to identify pathomorphological anomalies in dystrophic muscle, hypertrophied muscle and ageing muscle thereby contributing to a better understanding of why and how these processes occur. references 1. allbrook d. skeletal muscle regeneration. muscle nerve 1981; 4: 234-45. 2. allen re, boxhorn lk. regulation of skeletal muscle satellite cell proliferation and differentiation by transforming growth factor-beta, insulin-like growth factor i, and fibroblast growth factor. j cell physiol 1989; 138: 311-5. 3. barjot c, cotten ml, goblet c, whalen rg, bacou f. expression of myosin heavy chain and of myogenic regulatory factor genes in fast or slow rabbit muscle satellite cell cultures. j muscle res cell motil 1995; 16: 619-28. 4. barjot c, rouanet p, vigneron p, janmot c, d'albis a, bacou f. transformation of slowor fast-twitch rabbit muscles after cross-reinnervation or low frequency stimulation does not alter the in vitro properties of their satellite cells. j muscle res cell motil 1998; 19: 25-32. 5. bischoff r. the satellite cell and muscle regeneration. in: engel ag, franzini-armstrong c, eds. myology. new york: mcgraw-hill, 1994: 97118. 6. bittner re, schofer c, weipoltshammer k, et al. recruitment of bone-marrow-derived cells by skeletal and cardiac muscle in adult dystrophic mdx mice. anat embryol 1999; 199: 391-6. 7. brown sc, stickland nc. satellite cell content in muscles of small and large mice. j anat 1993; 183: 91-6. 8. cornelison dd, wold bj. single-cell analysis of regulatory gene expression in quiescent and activated mouse skeletal muscle satellite cells. dev biol 1997; 191: 270-83. 9. creuzet s, lescaudron l, li z, fontaine-perus j. myod, myogenin, and desmin-nls-lacz transgene emphasize the distinct patterns of satellite cell activation in growth and regeneration. exp cell res 1998; 243: 241-53. 10. dodson mv, mcfarland dc, grant al, doumit me, velleman sg. extrinsic regulation of domestic animal-derived satellite cells. domest anim endocrinol 1996; 13: 107-26. 11. ferrari g, cusella-de angelis g, coletta m, et al. muscle regeneration by bone marrow-derived myogenic progenitors. science 1998; 279: 1528-30. 12. garry dj, meeson a, elterman j, et al. myogenic stem cell function is impaired in mice lacking the forkhead/winged helix protein mnf. proc natl acad sci usa 2000; 97: 5416-21. 13. gibson mc, schultz e. the distribution of satellite cells and their relationship to specific fiber types in soleus and extensor digitorum longus muscles. anat rec 1982; 202: 329-37. 14. gibson mc, schultz e. age-related differences in absolute numbers of skeletal muscle satellite cells. muscle nerve 1983; 6: 574-80. 15 goodell ma, brose k, paradis g, conner as, mulligan rc. isolation and functional properties of murine hematopoietic stem cells that are replicating in vivo. j exp med 1996; 183: 1797-806. 16. goodell ma, jackson ka, majka sm, et al. stem cell plasticity in muscle and bone marrow. ann n y acad sci 2001; 938: 208-18. 17. gregory ma, mars m. alterations in the morphology of skeletal myofibers after 90 minutes of ischaemia and 3 hours of reperfusion. s afr med j 1991; 79: 307-11. 18. gregory ma, mars m. serial morphological changes in primate skeletal myofibers after 3 hours of ischaemia and 24 hours of reperfusion. s afr med j 1992; 81: 473-8. 19. grounds md. towards understanding skeletal muscle regeneration. pathol res pract 1991; 187: 1-22. 20. grounds md. muscle regeneration: molecular aspects and therapeutic implications. curr opin neurol 1999; 12: 535-43. 21. halevy o, hodik v, mett a. the effects of growth hormone on avian skeletal muscle satellite cell proliferation and differentiation. gen comp endocrinol 1996; 101: 43-52. 22. hawke tj, garry dj. myogenic satellite cells: physiology to molecular biology. j appl physiol 2001; 91: 534-51. 23. jackson ka, mi t, goodell ma. hematopoietic potential of stem cells isolated from murine skeletal muscle. proc natl acad sci usa 1999; 96: 14482-6. 24. karnovsky mj. a formaldehyde glutaraldehyde fixative of high osmolarity for use in electron microscopy. j cell biol 1965; 26: 31-4. 25. karpati g, pouilot y, zubrzycka-gaarn ee, et al. dystrophin is expressed in mdx skeletal muscle fibers after normal myoblast implantation. am j pathol 1989; 135: 27-32. 26. kelly am. perisynaptic satellite cells in the developing and mature rat soleus muscle. anat rec 1978; 190: 891-903. 27. kurek jb, bower jj, romaella m, koentgen f, murphy m, austen l. the role of leukemia inhibiting factor in skeletal muscle regeneration. muscle nerve 1997; 20: 815-22. 28. law pk, goodwin tg, wang mg. normal myoblast injections provide genetic treatment for murine dystrophy. muscle nerve 1988; 11: 525-33. 29. leroith d, mcguiness m, shemer j, et al. insulin-like growth factors. biol signals 1992; 1: 173-81. 30. mauro a. satellite cell of skeletal muscle fibers. j biophys biochem cytol 1961; 9: 493-8. 31. mccormick km, schultz e. role of satellite cells in altering myosin expression during avian skeletal muscle hypertrophy. dev dyn 1994; 199: 52-63. 32. muir ar, kanji ah, allbrook d. the structure of the satellite cells in skeletal muscle. j anat 1965; 99: 435-44. 33. olmesdahl pj, gregory mj, cameron ewj. ultrastructural artefacts in biopsied normal myocardium and their relevance to myocardial biopsy in man. thorax 1979; 34: 82-90. 34. ordahl cp, williams ba, denetclaw w. determination and morphogenesis in myogenic progenitor cells: an experimental embryological approach. curr top dev biol 2000; 48: 319-67. 35. reynolds es. the use of lead citrate at high ph as an electron opaque stain in electron microscopy. j cell biol 1962; 17: 208-12. 36. rosenblatt jd, yong d, parry dj. satellite cell activity is required for hypertrophy of overloaded adult rat muscle. muscle nerve 1994; 17: 608-13. 37. sakuma k, watanabe k, sano m, et al. the adaptive response of transforming growth factor-2 and -rii in the overloaded and regenerating and denervated muscle of rats. acta neuropathol 2000; 99: 177-85. 38. schmalbruch h, hellhammer u. the number of nuclei in adult rat muscles with special reference to satellite cells. anat rec 1977; 189: 169-75. 39. schultz e. satellite cell behavior during skeletal muscle growth and regeneration. med sci sport exerc 1989; 21: s181-6. 40. schultz e, jaryszak dl, gibson mc, albright dj. absence of exogenous satellite cell contribution to regeneration of frozen skeletal muscle. j muscle res cell motil 1986; 7: 361-7. 41. schultz e, jaryszak dl, valliere cr. response of satellite cells to focal skeletal muscle injury. muscle nerve 1985; 8: 217-22. 42. schultz e, mccormick km. skeletal muscle satellite cells. rev physiol biochem pharmacol 1994; 123: 213-57. 43. seale p, rudnicki ma. a new look at the origin, function, and "stem-cell" status of muscle satellite cells. dev biol 2000; 218: 115-24. 44. sheehan sm, allen re. skeletal muscle satellite cell proliferation in response to members of the fibroblast growth factor family and hepatocyte growth factor. j cell physiol 1999; 181: 499-506. 45. snow mh. myogenic cell formation in regenerating rat skeletal muscle injured by mincing. i. a fine structural study. anat rec 1977; 188: 181-99. 46. spurr ar. a low viscosity embedding medium for electron microscopy. j ultrastruct res 1969; 26: 31-4. 47. thorsson o, rantanen j, hurme t, kalimo h. effects of nonsteroidal antiinflammatory medication on satellite cell proliferation during muscle regeneration. am j sports med 1998; 26: 172-6. 48. watt dj, morgan je, clifford ma, partridge ta. the movement of muscle precursor cells between adjacent regenerating muscles in the mouse. anat embryol 1987; 175: 527-36. 49. winchester pk, gonyea wj. regional injury and the terminal differentiation of satellite cells in stretched avian slow tonic muscle. dev biol 1992; 151: 459-72. 50. wokke jh, van den oord cj, leppink gj, jennekens fg. perisynaptic satellite cells in human external intercostal muscle: a quantitative and qualitative study. anat rec 1989; 223: 174-80. original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license osteoarthritic changes in the knees of recently retired male professional footballers: a pilot study s carmody,1,2 md; h aoki,3,4 md; o kilic,1,5 md; m maas,5,6,7 phd; a massey,8 md; gm kerkhoffs,1,5,7,9 phd; v gouttebarge,1,5,9,10,11 phd 1 amsterdam umc location university of amsterdam, department of orthopedic surgery and sports medicine, meibergdreef 9, amsterdam, the netherlands 2 medical department, chelsea football club, london, united kingdom 3 st. marianna university school of medicine, kawasaki, japan 4 yokohama city sports medical center, yokohama, japan 5 amsterdam collaboration on health & safety in sports (achss), ioc research center, amsterdam, the netherlands 6 amsterdam umc location university of amsterdam, department of musculoskeletal radiology, meibergdreef 9, amsterdam, the netherlands 7 academic center for evidence based sports medicine (aces), amsterdam, the netherlands 8 medical department, fédération internationale de football association (fifa), zurich, switzerland 9 amsterdam movement sciences, aging & vitality, musculoskeletal health, sports, amsterdam, the netherlands 10 section sports medicine, university of pretoria, pretoria, south africa 11 football players worldwide (fifpro), hoofddorp, the netherlands corresponding author: v gouttebarge (v.gouttebarge@amsterdamumc.nl) knee injuries are common amongst male professional footballers (soccer players).[1] the management of these injuries may occasionally require surgical intervention, and this, along with the impact of repetitive joint loading, compounds the risk of complications, such as early-onset knee osteoarthritis (oa) for footballers in later life.[2] knee oa is prevalent amongst retired professional footballers, with studies reporting a high prevalence [2][3][4], although it is not currently considered an occupational disease.[7] it is a disabling condition manifesting in pain, swelling, stiffness and loss of range of motion. knee oa and its sequelae place a significant health burden on individuals and healthcare services worldwide, with affected individuals often unable to work, dependent on medication to complete activities of daily living (adls), and in many cases requiring surgical intervention (e.g. total knee replacement, tkr).[5] the diagnosis of knee oa, based on suggestive clinical features (e.g. activity-related joint pain, functional impairment), is often supported by the presence of joint space narrowing on radiographic examination.[6] previous studies have estimated the prevalence of knee oa in retired footballers to be as high as 80%,[4] with retired footballers three times more likely to report a diagnosis of knee oa than those in an agematched general population.[2] the interpretation of this high prevalence is limited by the fact that the definition of knee oa varies across epidemiological studies, with radiological (e.g. xray) knee oa, clinical knee oa (e.g. physical signs and symptoms), self-reported knee oa, all being considered in addition to those on the waiting list for (or having received) knee arthroplasty for knee oa. while oa is thought to be associated with reduced quality of life and mental health symptoms amongst retired athletes,[8] there is limited evidence examining the relationship between the extent of radiological knee oa (e.g. joint space narrowing) and patient reported outcome measures (proms) related to pain/impairments and quality of life. proms are used in oa to assess domains, such as pain, functional status and structural damage. established proms, such as the western ontario mcmaster universities' background: knee osteoarthritis (oa) is common amongst retired male professional footballers. there is limited understanding with respect to the interplay between imaging findings, clinical presentation and patient-reported outcome measures (proms) in retired professional footballers with knee oa. objectives: this pilot study aimed to evaluate the extent of radiological and clinical knee oa in a cohort of retired male professional footballers, and to explore the relationship between these findings and knee-related proms. methods: fifteen retired male professional footballers underwent knee radiographs and were surveyed on their history of clinical oa, severe knee injury and previous knee surgery. the knee injury and osteoarthritis outcome score physical function short form (koos-ps) and the patient-reported outcomes measurement information system global health (promis-gh) were used to assess health outcomes, such as level of function and pain. results: radiological knee oa was diagnosed in six out of 15 participants. seven of the participants had a clinical diagnosis of knee oa. evidence of clinical and radiological oa was present amongst four participants. radiological knee oa and clinical oa was significantly associated with a history of severe knee injury and previous knee surgery. low correlations (ρ<-0.40) were found between knee oa severity and knee-related proms. moderate correlation (ρ=-0.65) was found between clinical knee oa and koos-sp. conclusion: clinical knee oa correlates with proms amongst retired professional footballers but radiological oa does not. further studies are required to understand the relationship between imaging findings, clinical presentation and proms amongst retired professional footballers with knee oa. keywords: osteoarthritis, knee injuries, professional footballers, retirement s afr j sports med 2022;34:1-6. doi: 10.17159/2078-516x/2022/v34i1a12816 mailto:v.gouttebarge@amsterdamumc.nl http://dx.doi.org/10.17159/2078-516x/2022/v34i1a12816 https://orcid.org/0000-0002-8106-6380 https://orcid.org/0000-0001-8683-5532 https://orcid.org/0000-0002-8253-932x https://orcid.org/0000-0002-0126-4177 https://orcid.org/0000-0001-5916-7049 original research sajsm vol. 34 no.1 2022 2 osteoarthritis index (womac) and the knee injury and osteoarthritis outcome score (koos), are the most common measures of functional status that have been used for knee oa.[9][10] the seven-item knee injury and osteoarthritis outcome score physical function shortform (koos-ps) is an abbreviated prom and has been shown to be valid and reliable for assessing the impact of oa on patient function.[11] understanding the relationship between the extent of oa, quality of life, and function amongst retired professional footballers may provide insight into potential interventions to improve outcomes in this cohort. therefore, the primary objective of this pilot study was to evaluate the extent of radiological and clinical knee oa in a cohort of retired male professional footballers, and to explore the relationship between these findings and knee-related proms. methods study design an observational study based on a cross-sectional design was conducted, using the strengthening the reporting of observational studies in epidemiology (strobe) statement in order to ensure a high quality of reporting.[12] ethical approval for the study was provided by the ethical committee of the yokohama city sports medical center (17.003; yokohama, japan) and the medical ethics review committee of the academic medical center, (w16_366#16.431) amsterdam, the netherlands). the study was conducted in accordance with the principles set out in the declaration of helsinki (2013).[13] players participated voluntarily in the study and did not receive any financial remuneration for their participation. participants a sample of 15 recently retired professional footballers (six finnish, four norwegians, three dutch, two americans) was recruited by football players worldwide (fifpro), the international union for professional footballers. the inclusion criteria were: (1) retired professional football player, (2) aged up to 50 years, (3) male sex and (4) ability to understand text written in english. in our study, a retired male professional footballer was defined as an individual who was remunerated for devoting several hours in all/most days (exceeding the time allocated to other types of professional or leisure activities) to playing football, and in which they competed in the highest or second highest national league. the following exclusion criterion was defined: those with a confirmed diagnosis of other forms of arthritis or systemic medical conditions with a predilection for joint manifestations. radiological and clinical knee osteoarthritis two-sided weight-bearing knee radiographs were performed (rosenberg view, standing anteroposterior view, standing lateral view) according to a standardised protocol. knee joint space narrowing was assessed by an experienced radiologist (mm) and classified according to kellgren-lawrence criteria (from grade 0 to grade 4), with oa also being deemed as present at grade 3 or grade 4.[14][15] participants were invited to disclose any confirmed history of clinical knee oa. clinical knee oa was defined according to the nice criteria (adapted for age) as damage of the knee joint’s cartilage leading to activity-related joint pain and either no morning joint-related stiffness or morning stiffness that lasts no longer than 30 min.[16] knee-related patient-reported outcome measures the history of severe knee injury and subsequent surgery during a career as a professional footballer was examined by means of a single question; ‘how many severe knee injuries have you had during your career as a professional footballer?’ in our study, a severe knee injury was defined as; ‘an injury that involved the knee joint, occurred during team activities (training or match), and led to either training or match absence for more than 28 days’.[17] the validated knee injury and osteoarthritis outcome score physical function short form (koos-ps) was used to assess the level of knee function.[11] a total score ranging from 0 to 100 was calculated, where 0 represented complete knee disability and 100 indicated impeccable knee function.[18] reference values for physical knee function are available for standard adult populations, young athletic populations, and amongst amateur footballers.[18][19][20] the patient-reported outcomes measurement information system global health (promis-gh) was used to assess multiple domains related to health-related quality of life, such as physical health, levels of function, pain, social activities and fatigue, for this study.[21] based on 10 items, each measured on a five-point scale (from one to five), the global physical health and global mental health scores were calculated. these subscale scores ranged from 0 to 100, with a higher score indicating a better quality of life and a mean score of 50 indicating the norm for the general population. procedures an electronic anonymous questionnaire (see supplementary material) available in english was compiled (limesurvey professional), including for all proms, as well as the following descriptive variables: age, height (cm), weight (kg), duration of professional football career, level of play, level of education, duration and nature of retirement, and current employment status. information about the study was emailed to potential participants by fifpro, with the process hidden from the principal researcher for privacy reasons and to minimise the risk of researcher bias. if interested in the study, participants gave their informed consent and were asked to visit a clinic of their choice for the aforementioned standardised radiological assessment. participants were concurrently asked to complete the electronic questionnaire. the responses to the questionnaires were coded and made anonymous for reasons of privacy and confidentiality. once completed, all data collected were saved automatically on a secure electronic server that only the principal researcher could access. statistical analysis the statistical software ibm spss 26.0 for apple mac was used original research 3 sajsm vol. 34 no.1 2022 for data analysis. descriptive analyses (mean, standard deviation, frequency and range) were performed for all variables included in the study. correlation between radiological knee oa and clinical knee oa with knee-related proms was explored with spearman's rank correlation coefficient (ρ).[22] results the respective mean age, height and weight of the participants was 39 years (sd=4), 183 cm (sd=5) and 82 kg (sd=7). participants must have played professional football for 13 years on average (87% at the highest club level in their country) and been retired for five years. two (13%) participants were forced to retire through injury. all the characteristics of the participants are presented in table 1. the main findings of the study are presented in table 2. radiological knee oa was diagnosed in six participants (40%; two bilateral and four unilateral). seven (47%) of the participants had a clinical diagnosis of knee oa. four (27%) of the participants had evidence of both clinical and radiographic knee oa. figure 1 displays the radiographs (rosenberg view) of two of the participants, one without radiological oa (grade 0) (top two radiographs) and one with bilateral (grade 3 and grade 4) radiological oa (bottom two radiographs). a chi-square test indicated that radiological knee oa was significantly associated with severe knee injury (χ2 = 3.64; df = 1; p < 0.10) and knee surgery (χ2 = 3.62; df = 1; p < 0.10). achi-square test indicated that clinical knee oa was significantly associated with both severe knee injury (χ2 = 4.77; df = 1; p < 0.10) and knee surgery (χ2 = 5.53; df = 1; p < 0.10).the mean score on the koos-sp was 88. the global physical health and global mental health mean scores were 55 and 54, respectively. low correlations (ρ<-0.40; p>0.10) were found between radiological knee oa severity and knee-related proms. moderate correlation (ρ=-0.65; p<0.01) was found between clinical knee oa and koos-sp. discussion this pilot study investigated the presence of knee oa amongst retired male professional footballers, and explored the relationship between these findings and knee-related proms. there was evidence of radiological knee oa in 40% of participants, and 47% showed signs of clinical oa. a history of previous severe knee injury and/or previous knee surgery was significantly correlated with the presence of radiological knee oa. there was no apparent correlation between the severity of radiological knee oa and proms. the presence of clinical knee oa was moderately correlated with impaired function. perspective of the findings the findings in this study support the findings of table 1. descriptive characteristics of retired professional footballers (n=15) age (years) 39 ± 3.6 height (cm) 183 ± 5.0 weight (kg) 82 ± 7.4 body mass index (kg/m2 ) 24.6 ± 1.7 career duration (years) 13 ± 2.8 level of play (top league; %) 87 educational level (%): no schooling completed 0 nursery/elementary school 0 high school 7 vocational/technical school 7 college, university or equivalent 86 retirement duration (years) 5.0 ± 4.1 forced retirement (%) 13 employed (%) 93 data are expressed mean ± sd unless indicated otherwise. table 2. knee-related injury, surgery, osteoarthritis and patient-reported outcome measures among retired professional footballers (n=15) severe knee injury (%) none 27 one or two 60 three or more 13 knee surgery (%) none 47 one or two 33 three or more 20 radiological findings of knee osteoarthritis (%) no radiological findings of osteoarthritis 7 doubtful narrowing of joint space and possible osteophytic lipping 20 definite osteophytes and possible narrowing of joint space 33 moderate multiple osteophytes, definite narrowing of joint space, small pseudocystic areas with sclerotic walls and possible deformity of bone contour 13 large osteophytes, marked narrowing of joint space, severe sclerosis and definite deformity of bone contour 27 radiological and clinical knee osteoarthritis (%) no 73 yes 27 radiological knee osteoarthritis (%) no 60 yes 40 clinical knee osteoarthritis (%) no 53 yes 47 koos-sp 88 ± 16 reference value koos-sp (mean) general population 87-92 young athletic population 86-99 amateur footballers 87-96 global physical health* 55 ± 7.1 global mental health* 54 ± 9.9 data are expressed mean ± sd unless indicated otherwise. koos-sp, knee injury and osteoarthritis outcome score physical function short form; *mean score of 50 indicating the norm for the general population. original research sajsm vol. 34 no.1 2022 4 earlier research which identified that knee oa is prevalent amongst retired male professional footballers. the correlation between knee oa and previous severe knee injury and/or previous knee surgery is also consistent with previous studies.[23] oa is not considered an occupational disease for professional footballers, but it has been shown to have a higher prevalence amongst retired male professional footballers when compared to those in the general population or in active footballers. it is reported that 18% of the general uk population sought treatment for knee oa and 8% have sought treatment for hip oa.[16] the prevalence of knee oa (13%) amongst current professional footballers is significantly less than that amongst retired professional footballers.[23] radiological versus clinical knee osteoarthritis radiological oa is not a reliable predictor of clinical outcomes in oa.[24] in this pilot study, there was no significant correlation between radiological knee oa and proms. this is consistent with a broad body of literature highlighting that radiological findings are not necessarily consistent with clinical findings.[25] moderate correlation was found between clinical knee oa and koos-sp, indicating that pain and function may be a more useful guide to determine the presence and impact of knee oa in retired male professional footballers. future directions: clinical practice this pilot study provides a reference for future studies to examine the complex interplay between imaging findings, clinical presentation, quality of life and other health outcomes amongst retired professional footballers with knee oa. identifying those most at risk of negative sequelae may allow for more targeted interventions during and after a player’s career. these interventions may extend to workload monitoring, better surgical decision-making and lifestyle advice upon retirement. recently, an after career consultation (acc) was developed in order to empower the sustainable physical, mental and social health, and the quality of life of retired professional footballers.[26] during the acc, recently retired professional footballers receive evidencebased lifestyle advice which may mitigate their risk of developing oa.[27] further studies are required to assess the efficacy of any such interventions aimed at preventing or reducing the burden of knee oa amongst retired professional footballers. future directions: research this pilot study provides an initial insight into the relationship between clinical knee oa, radiological oa and proms in a cohort of 15 retired male professional footballers. expanding the study may provide additional insights which can be used to mitigate the risk of knee oa in retired male professional footballers. a recent scoping review highlighted that there are very few studies examining the presence of musculoskeletal conditions in retired female professional footballers.[28] only two studies were identified which assessed the prevalence of knee oa in retired female professional footballers, prevalence ranging from 14% to 60%.[28] further studies are required to understand the impact of clinical knee oa and radiological knee oa on proms in this population. limitations several methodological limitations should be acknowledged. firstly, our study was only a pilot study conducted to help in the design of future larger cohort studies and defining support measures, such as the acc.[26] we therefore used only a small sample size, which might have affected the study’s external validity making it difficult to generalise the findings. however, our pilot study may pave the way for future studies investigating the relationship between clinical oa, radiological oa and proms. using more advanced imaging (e.g. mri) to assess for radiological oa may have provided more detailed findings. secondly, information about severe knee injuries and knee surgery was self-reported. professional footballers can generally recall quite accurately the number of severe injuries and surgeries they had that led to at least four weeks without training or competition. however, recall bias cannot be categorically excluded. thirdly, it is very likely that knee injuries and knee surgeries have occurred prior to the development of knee oa. however, because of our cross-sectional design, such a time sequence is difficult to establish with certainty. lastly, our pilot study included key features, such as history of previous severe knee injury and knee surgery, career fig. 1. knee radiographs (rosenberg view) of two retired professional footballers (top two radiographs: grade 0; bottom two radiographs: grade 3-4). the bottom two radiographs demonstrate radiological features of oa including loss of joint space and osteophytes. original research 5 sajsm vol. 34 no.1 2022 duration and level of play. other details, such as career earnings and nationality, may have provided useful confounding data. future studies may extend exclusion criteria to exclude any participants who have experienced trauma to the knee joint not directly related to playing football (e.g. motor vehicle accidents, injurious falls, etc.). conclusion clinical knee oa correlates with proms amongst retired professional footballers but radiological oa does not. further studies are required to understand the relationship between imaging findings, clinical presentation and proms amongst retired professional footballers with knee oa. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors are grateful to all retired professional footballers who participated in the study. author contributions: ha, mm, gmk and vg were involved in the design of the study and data collection. sc was responsible for data analysis. all authors were responsible for data interpretation. sc drafted the manuscript, with critical review provided by all authors. all authors approved the final version of the 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[doi: 10.1136/bmjsem2021-001196][pmid: 35528132] original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license absolute and relative reliability of scrum test battery components assembled for schoolboy rugby players playing competitive rugby in low-resource settings: a pragmatic in-season test-retest approach m chiwaridzo,1,2 phd; c tadyanemhandu,3 phd; ns mkumbuzi,4 phd; jm dambi,1 phd; gd ferguson,2 phd; bc smits-engelsman,2 phd 1 university of zimbabwe, faculty of medicine and health sciences, department of primary health care sciences, rehabilitation unit, harare, zimbabwe 2 university of cape town, faculty of health sciences, department of health and rehabilitation sciences, division of physiotherapy, cape town, south africa 3 midlands state university, faculty of medicine and health sciences, physiotherapy department, gweru, zimbabwe 4 university of cape town, health through physical activity, lifestyle and sports research centre, department of human biology, cape town, south africa corresponding author: m chiwaridzo (matthewchiwaridzo@yahoo.co.uk) increased competition demands worldwide at the elite senior level have prompted professional rugby union (ru) clubs and national ru governing bodies to invest in talent identification (tid) and long-term junior development programmes.[1-3] these efforts have produced a pool of young rugby players with the potential to become successful future elite athletes, strengthening the growth and development of rugby. the process of tid is dependent on screening tests that measure the important characteristics of rugby players. the tests should be practically feasible and have acceptable psychometric properties. however, there are many test batteries available in the literature profiling young rugby players with heterogeneous compositions [4] and unclear details on the measurement properties of the constituent tests. regardless of age and playing standards, ru is a physically and technically challenging sport requiring commensurate physiological adaptations and specialised training of rugbyspecific skills for optimal performances. [1] a combination of appropriate anthropometric qualities, physiological characteristics, and rugby-specific skills defines the key attributes warranted by participants for effective performances. test batteries that are logically validated to the needs of the young rugby players, which also contain practically feasible and reliable tests are more likely to be relevant for use in the tid programs. in addition, coaches, strength and conditioning experts and sports scientists can use them for longitudinal monitoring of athletic motor skills, technical performances, and responses to injury rehabilitation. cross-sectionally, such test batteries can provide data on players’ competency levels assisting in player team selection, and an individual athlete’s profile in terms of anthropometric, physiological and game-specific characteristics. therefore, following the development of the first version of the scrum (school clinical rugby measure) test battery and subsequent evaluation of face recognition methods, logical validity and practical feasibility of the component test items [4-6], the specific objectives of this study were to identify test items in the scrum test battery with an acceptable coefficient of variation and high intraclass correlation coefficient (icc) as a measure of absolute and relative reliability among a sample of young rugby players. methods study design, research setting and participants experimentally, the study was conducted as a test-retest reliability study using under 19 (u19) schoolboys playing competitive rugby in harare, zimbabwe. the only pathway for junior ru development in zimbabwe is within the school system. in a bid to promote and strengthen junior rugby in high schools, the ministry of primary and secondary education in zimbabwe, established the super eight schools rugby league (sesrl). the sesrl features the eight most competitive rugbybackground: schoolboy rugby is a popular sport which forms the bedrock of rugby development in many african countries, including zimbabwe. with burgeoning talent identification programmes, the development of multi-dimensional, logicallyvalidated, and reliable test batteries is essential to inform the objective selection of potentially talented young rugby athletes. objectives: this study sought evidence on the absolute and relative test-retest reliability of the component test items in the newly-assembled scrum test battery. methods: utilising a pragmatic test-retest experimental design, a sample of 41 under-19 schoolboy players playing competitive rugby in the elite super eight schools rugby league in harare, zimbabwe, participated in the study. results: physiological and game-specific skills tests which showed good to excellent relative reliability and acceptable absolute reliability, included: 20 m and 40 m speed, l-run, vertical jump (vj), 60 s push-up, 2 kg medicine ball chest throw test (2 kg mbct), wall sit leg strength test (wsls), repeated high intensity exercise test (rhie), one repetition maximum back squat (1-rm bs) and bench press tests (1-rm bp), yo-yo intermittent recovery level 1 test (yo-yo irt l1), tackling proficiency test, passing ability skill test and running and catching ability skill test. conclusion: all these tests are reliable and warrant inclusion in the scrum test battery for possible profiling of u19 schoolboy rugby players during the ‘in-season’ phase provided there is adequate participant familiarisation and test standardisation. the test-retest iccs and measurement errors are generalisable to other young athletes in this population, making the tests useful for the evaluation of training and developmental effects of the measured constructs. keywords: intraclass correlation, reproducibility, rugby union, under 19, zimbabwe, africa s afr j sports med 2021;33:1-7. doi: 10.17159/2078-516x/2021/v33i1a12220 mailto:matthewchiwaridzo@yahoo.co.uk http://dx.doi.org/10.17159/2078-516x/2021/v33i1a12220 https://orcid.org/0000-0003-4470-9604 https://orcid.org/0000-0002-2446-7903 https://orcid.org/0000-0002-4982-0662 https://orcid.org/0000-0003-0632-3276 https://orcid.org/0000-0003-1610-3699 https://orcid.org/0000-0002-2698-965x original research sajsm vol. 33 no. 1 2021 2 playing government (n=2) and private (n=6) high schools across the country and is generally considered as the “elite” rugby-playing league. all the sesrl schools have a local reputation for a strong and long-standing culture of playing competitive rugby. [4] annually, the sesrl produces u19 rugby players capable of joining adult professional clubs. using tables from the walter et al. [7] study, the estimated sample size was 18 participants utilising the following parameters for two replicate measures: h0: p0 (minimally acceptable level of reliability) =0.7, h1: p1=0.9 (maximum expected value of reliability), beta (β) =0.2, alpha (α) =0.05. however, due to multiple tests in the scrum test battery and the study design involving two repeated measures, oversampling was done. of the 59 schoolboy rugby players invited to participate, 41 completed all the tests. ethical approval was obtained from the medical research council of zimbabwe (ref: mrcz/a/2070) and the human research ethics committee from the university of cape town (ref: 016/2016). institutional permissions were obtained from the ministry of primary and secondary education and harare provincial educational office, zimbabwe. prior to data collection, written informed consent and assent were obtained from the guardians/parents and the children, respectively. data collection approach a pragmatic “in-season” approach previously used by enright et al. [11] was adopted for the study. specifically, the study sought to determine the reliability of scrum tests when test-retest assessments are scheduled during training days without disturbing the classes, training schedules, and competitive match days. this approach was more likely to get approval from the coaching staff, parents, and school authorities given the multitude of tests in the scrum test battery and the repeated measures. the design required all participants to perform the scrum test items on two separate occasions at the same time and day. two familiarisation sessions were conducted to ensure sufficient exposure of the study participants to the scrum test items. for the second session, eligible participants completed a brief questionnaire which solicited demographic and rugby-related information. participant testing commenced during the competitive season. this approach ensured that participants had match physical fitness and were close to peak performance. on any day of testing, participants completed the physical activity readiness questionnaire (par-q) and were excluded if they reported injuries, illness, or health-related conditions aggravated by exertion. subsequently, eligible participants completed a standardised warm-up procedure before testing. the order of testing was as indicated in supplementary file 1. a recovery period of 10 minutes was allowed between tests to minimise fatigueinduced effects. the re-test assessments were conducted after seven days, at the same time for each participant. two well-trained research assistants conducted all the scrum tests, except for skinfolds and game-specific skills. the latter tests were conducted by a purposively-recruited anthropometrist and rugby coaches respectively. each assistant always assessed the same athlete. testing occurred on a natural grass pitch for field tests and in a gymnasium for strength/power-based tests with participants who were requested to wear the same clothing each time. the researchers provided similar verbal encouragement to all participants during the test. test results were deliberately withheld from the participating athletes to avoid influencing re-test performances. additionally, participants were unaware of the seven-day interval for the re-test assessments and were advised to maintain a normal diet, adequate hydration, and to avoid taking ergogenic aids during the experimental period. the scrum test battery the scrum test battery was composed of (i) anthropometric variables (height, sitting height, body mass, seven skinfold measurements which included biceps, triceps, subscapular, suprailiac, abdomen, thigh, and calf measures), (ii) physiological characteristics (speed, agility, upper-and-lower muscular strength and power, prolonged high-intensity intermittent running ability, muscle flexibility and repeated high-intensity exercise performance ability) and (iii) rugby-specific game skills (tackling proficiency, passing ability, passing-for-accuracy, and running-and-catching ability). the full description of the scrum test battery and methodological procedures followed for the test execution are included as supplementary file 2. briefly, linear speed was measured using the 5 m, 10 m, 20 m, and 40 m speed tests. agility was assessed using the l-run agility test. upper and lower body muscular strength was assessed using the one repetition maximum bench press test and one repetition maximum back squat test, respectively. two further tests were also included to assess upper and lower body muscular strength: wall sit leg strength, and 60s-push up. upper-and lower muscular power were assessed using the vertical jump and 2 kg medicine ball chest throw tests. prolonged highintensity intermittent running ability was evaluated using the yo-yo intermittent recovery level 1 test. lower back and hamstring muscle flexibility were assessed using the sit-andreach test. the repeated high-intensity exercise performance ability of the participants was evaluated using the repeated high intensity exercise (rhie) tests. the development of the scrum test battery was based on recommendations from the literature on instrument or test battery development. briefly, the development process followed a multi-phased approach which involved conducting: i. a narrative literature review to establish what is known about the key requirements of rugby, specifically targeting anthropometric, physical or physiological characteristics, and rugby-specific game skills in the literature ii. a qualitative exploratory study to gather the perceptions of rugby coaches on the key attributes or qualities and game skills needed in rugby and should be incorporated in test batteries for tid programs. this part of the approach also sought commonly used test(s) for the identified attributes and skills used in the local context iii. a systematic literature review to determine the physical or physiological characteristics and rugby-specific game skills frequently covered in the literature and their corresponding tests. furthermore, the evaluation of the original research 3 sajsm vol. 33 no. 1 2021 psychometric properties of each identified test per construct was also undertaken. the above-mentioned processes engendered the first version of the test battery which was subsequently evaluated for face validity, logical validity and practical feasibility. therefore, this present study aims to evaluate the reliability of the content-validated and practically-feasible version of the scrum test battery. statistical analysis data analysis was carried out using spss statistical software version 26. the shapiro-wilk test assessed the normality of continuous variables (p<0.05). descriptive statistics (mean±sd) described parametric data. paired samples t-test evaluated any systematic bias between trials (p<0.05). cohen’s d effect size (es) statistic determined the magnitude of the difference between test-retest measurements.[9] the criteria for interpreting the magnitude of the es were as follows: <0.2 trivial, 0.2-0.6 small, >0.6-1.2 moderate and >1.2 large. relative reliability was determined by calculating the two-way random intra-class correlation coefficient (icc 2, 1) for absolute agreement of single measures. however, average icc measures were reported for the tackling proficiency test because an average of six test trials were recorded to represent participant tackling score (see supplementary file 2). the 95% confidence interval (ci) was calculated testing if each icc was equal to zero using the f-ratio. icc values above 0.7 were considered acceptable for test-retest reliability. [10] to test for absolute reliability, the standard error of measurement (sem) was calculated for each test. the sem provides expected trial to trial measurement error and was computed as a standard deviation of the differences (sddifferences) between test-retest assessments divided √2. [11] to facilitate the comparison of test reliability values between studies, the coefficient of variation (cv %) expressed the sem as a percentage of the grand mean [12], and an arbitrary cv boundary of <10% was considered acceptable [12]. the smallest detectable change (sdc95%) for each test was calculated by sem x 1.96 x √2. [13] results table 1 shows the demographics and rugby-related information of all participants. the mean age of the participants was 17.5±0.9 years. the median years of experience playing schoolboy rugby for the participants were five years (interquartile range, iqr four-five years). there was an equal representation of forward (49%) and backline (51%) players in the sample population. table 2 shows no systematic changes between trials for most scrum test items. the icc, sem, and sdc95% results for scrum test items are shown in table 3. overall, the iccs for the scrum test items ranged between 0.49 and 1.0. evidence of low test-retest reliability was found for the five m speed (icc=0.52; 95% ci=0.27-0.71), 10 m speed (icc=0.64; 95% ci=0.42-0.79) and passing-foraccuracy seven m tests (icc=0.49; 95% ci=0.22-0.69). the sr test exhibited the greatest variability with a cv of 17%. the sdc95% values for all scrum test items were greater than the sem values. discussion the purpose of this present study was to provide contextual evidence on the test-retest reliability of each of the component test items in the newly-assembled scrum test battery. the establishment of reliability is an extremely important step in test battery development as it provides information on the capacity of test items to differentiate participants or maintain the same relative order of participants in replicate measures under similar conditions. [14] the icc is the most commonly reported sample statistic providing evidence of relative reliability in the literature. it thrives on increased variability in the sample population for the measured construct and decreased measurement error. among 41 u19 schoolboy players, most scrum test items demonstrated no systematic bias, low cv% values, and high iccs, suggesting absolute and relative reliability when the assessments are made during the ‘in-season’ phase. these results reflect the careful manner in which scrum test items were implemented as well as temporal stability in the construct over the interval measured. overall, the high iccs could be attributed to the large between-subject variability observed for most test performances. this variability could potentially stem from natural differences in participant abilities, player position heterogeneity, or varied rugby experience. as expected, good to excellent iccs were shown for all anthropometric variables. however, 12 of the 14 physiological tests administered to u19 schoolboy rugby players showed good to excellent relative reliability. the tests included the following: 20 m and 40 m speed, modified l-run agility, vj, sr, 60 s push-ups, 2 kg mbct, wsls, rhie, 1 rm bs, 1 rm bp, table 1. sample demographics and rugby-related information (n=41) variable elite u19 players age (years) mean ± sd 17.5 ± 0.9 range (minimum-maximum) 15.6 18.9 playing experience years (median (iqr)) 5 (4-5) generic positions forwards, n (%) 20 (49) backs, n (%) 21 (51) specific regular positions props 7 flanks 5 locks 5 centres 5 fullbacks 4 scrumhalf 4 wingers 4 fly half 3 hooker 3 eighth man 1 sd, standard deviation; iqr, interquartile range. original research sajsm vol. 33 no. 1 2021 4 and the yo-yo irt l1. three tests (tackling, passing and catching) of the four rugby-specific game skills assessed had acceptable reliability. these findings suggest that all these tests warrant inclusion in the scrum test battery for possible profiling of u19 male adolescent rugby players provided there is adequate participant familiarisation and test standardisation. the 5 m and 10 m sprint tests showed low relative reliability among u19s. this questions the appropriateness for the inclusion of these speed tests in the scrum test battery for the respective age categories given the wide ci. furthermore, the sem of each speed test ranged from 0.0 to 0.1 seconds indicating error in consistencies across the speed distances. however, expressed as cv%, the sem increased with short speed distances and decreased with longer distances. for example, the cv% for the 10 m speed test was 4.5 compared to 1.0 for the 40 m speed test. these findings possibly indicate that the 40 m speed test is more reliable compared to the 10 m speed test among u19 rugby players. alternatively, the 20 m speed test was more reliable (cv%=1.8) compared to the 10 m speed test but less reliable for the 40 m speed test. these findings of high reliability for longer sprints (above 20 m) among u19s are comparable with previous findings reported elsewhere [15]. dobbin et al. [11] reported icc (cv %) of 0.69 (4.9) for 10 m speed test among 50 u19 academy rugby league players. however, besides differences in sample size and sport, there were methodological differences between the dobbin et al. [11] study and our study (i.e. use of timing gates vs an electronic handheld stopwatch; three repeated measures table 2. mean differences in scrum variables between test-retest results for elite u19s variable test re-test mean diff std diff p es [95% ci] effect anthropometry body mass (kg) 77.5 ± 9.6 77.6 ± 9.6 -0.1 0.3 0.1 -0.0 [-0.0-0.0] trivial height (m) 1.7 ± 0.1 1.73 ± 0.1 0.0 0.1 0.8 0.0 [0.0-0.0] trivial bmi (kgm-2) 25.9 ± 3.3 26.0 ± 3.3 -0.0 0.4 0.5 -0.3 [-0.1-0.1] trivial biceps (mm) 6.7 ± 3.6 6.46 ± 3.4 0.2 0.7 0.0* 0.1 [0.0-0.2] trivial triceps (mm) 9.4 ± 3.0 9.56 ± 2.8 -0.1 1.2 0.5 -0.0 [-0.1-0.2] trivial subscapular (mm) 12.8 ± 2.7 12.9 ± 2.6 -0.1 0.8 0.3 -0.0 [-0.1-0.2] trivial suprailiac (mm) 8.9 ± 3.8 9.02 ± 3.9 -0.1 0.8 0.4 -0.0 [-0.1-0.1] trivial abdomen (mm) 11.4 ± 2.9 11.7 ± 3.2 -0.3 1.4 0.2 -0.1 [-0.3-0.2] trivial thigh (mm) 10.0 ± 2.5 10.0 ± 2.5 -0.0 1.3 0.9 -0.0 [-0.0-0.0] trivial calf (mm) 5.5 ± 1.0 5.54 ± 1.0 -0.1 0.6 0.6 -0.1 [-0.2-0.1] trivial sum of skinfolds (mm) 64.7 ± 15.6 65.2 ± 15.2 -0.4 2.6 0.3 -0.0 [-0.1-0.1] trivial physiological tests 5m speed (s) 1.1 ± 0.0 1.11 ± 0.0 -0.0 0.0 0.07 -0.3 [-0.8-0.3] small 10m speed (s) 2.0 ± 0.1 2.03 ± 0.2 -0.0 0.1 0.23 -0.1 [-0.4-0.2] trivial 20m speed (s) 3.3 ± 0.2 3.22 ± 0.2 0.0 0.1 0.06 0.2 [-0.2-0.5] trivial 40m speed (s) 5.6 ± 0.3 5.58 ± 0.3 0.0 0.1 0.11 0.1 [-0.1-0.2] trivial l-run agility (s) 6.2 ± 0.3 6.20 ± 0.3 0.0 0.2 0.77 0.0 [-0.1-0.1] trivial vertical jump (cm) 47.8 ± 3.8 48.2 ± 3.8 -0.3 1.4 0.15 -0.1 [-0.3-0.1] trivial sit-and-reach (cm) 7.9 ± 5.1 8.51 ± 4.9 -0.6 2.0 0.05 -0.1 [-0.4-0.2] trivial 2-kg mbct (m) 9.3 ± 1.3 9.41 ± 1.3 -0.2 0.6 0.05 -0.1 [-0.4-0.1] trivial 60-s push-up (s) 49.7 ± 10.0 50.7 ± 10.6 -1.0 3.7 0.08 -0.1 [-0.3-0.1] trivial wall sit leg strength (sec) 146.1 ± 9.7 147.9 ± 8.3 -1.9 4.1 0.01* -0.2 [-0.6-(-0.1)] small 1-rm back squat (kg) 98.4 ± 14.8 98.8 ± 13.7 -0.4 2.9 0.35 -0.0 [-0.1-0.1] trivial 1-rm bench press (kg) 90.5 ± 16.4 90.7 ± 15.7 -0.4 3.4 0.51 -0.0 [-0.0-0.0] trivial rhie (s) 39.3 ± 3.0 39.7 ± 2.7 -0.4 1.8 0.20 -0.1 [-0.4-0.2] trivial yo-yo irt (m) 1505.9 ± 75.0 1522.4 ± 87.0 -16.6 60.6 0.09 -0.2 [-0.6-0.3] small game skills tests tackling (%) 87.9 ± 8.4 89.5 ± 8.6 -1.6 6.0 0.10 -0.2 [-0.6-0.2] trivial passing ability (au) 116.2 ± 2.1 116.5 ± 1.5 -0.3 1.4 0.18 -0.2 [-0.5-0.1] trivial pass accuracy (%) 89.3 ± 7.3 90.7 ± 5.6 -1.5 6.6 0.16 -0.2 [-0.6-0.2] small catching (au) 74.0 ± 1.1 74.2 ± 0.9 -0.2 0.8 0.07 -0.2 [-0.6-0.2] small data are expressed as mean ± sd. * indicates significant difference (p<0.05). mean diff, mean difference (test score-retest score); std diff, standard deviation difference; df, degrees of freedom; p value, 2 tailed probability value; es, cohen’s d effect size statistic with the 95% confidence interval; 2-kg mbct, 2 kg medicine ball chest throw; 1-rm, one repetition maximum; rhie, repeated high intensity exercise; yo-yo irt, yo-yo intermittent recovery test; tackling (%), tackling proficiency test; m, metres; kg, kilograms; s, seconds; au, arbitrary units; cm, centimetres; catching, running and catching ability test. original research 5 sajsm vol. 33 no. 1 2021 vs two repeated measures). in contrast, gabbett et al. [16] reported high iccs (cv %) for 5 m and 10 m speed tests of 0.84 (3.2) and 0.87 (1.9) respectively among 42 adult rugby league players. this shows that methodological, sport and population differences partly explain differences in the icc results between studies. reliability parameters depend on variations in the population sample for the measured construct, and the results have an external validity to populations with similar variations. [13] another key but unexpected finding was the low relative reliability for the passing-for-accuracy seven m test. this is explained by the lower variability between participants evidenced by smaller standard deviations in test and re-test scores. no previous study has reported the relative reliability of the passing-for-accuracy seven m test for u19 schoolboy rugby players referencing iccs values. pienaar et al. [17] reported test-retest correlations (r=0.66) and 95% limits of agreement (loa), suggesting moderate reliability among thirty-six 10-year-old schoolboys with varied rugby experience. nonetheless, the use of r has been criticised in contemporary literature since it evaluates the linearity of test scores in repeated measures. [18] instead, the icc is frequently reported for relative reliability. [19] nonetheless, the low reliability of the passing-for-accuracy seven m test in the present study could be linked to test novelty. unlike previous tests which had stationary rugby participants passing a ball to a static object placed seven m away, and judging the accuracy of hitting the target [17, 20], the present study had a dynamic recipient catching of a pass from a running player. the test also uniquely included a research assistant offering standardised defensive play to the tested player. all this was designed to test passing-for-accuracy as an open skill simulating real game situations. however, table 3. measures of reliability for the scrum test items among elite u19s variable icc [95% ci] sem [95%ci] cv (%) [95%ci] sdc [95%ci] anthropometry body mass (kg) 1.00 [0.99-1.00] 0.19 [0.09-0.31] 0.24 [0.10-0.35] 0.52 [0.39-0.78] height (m) 0.97 [0.95-0.99] 0.01 [0.01-0.03] 0.56 [0.43-0.67] 0.03 [0.03-0.05] biceps (mm) 0.98 [0.95-0.99] 0.52 [0.10-1.10] 7.88 [6.60-9.00] 1.44 [1.24-1.67] triceps (mm) 0.92 [0.85-0.95] 0.84 [0.20-1.40] 8.84 [6.34-9.10] 2.33 [2.08-2.55] subscapular (mm) 0.96 [0.92-0.98] 0.55 [0.42-0.64] 4.29 [3.12-5.13] 1.53 [1.01-1.89] suprailiac (mm) 0.98 [0.96-0.99] 0.54 [0.20-1.11] 6.05 [4.20-7.03] 1.51 [1.34-2.16] abdomen (mm) 0.89 [0.81-0.94] 0.99 [0.60-1.35] 8.57 [6.12-8.89] 2.74 [2.23-3.17] thigh (mm) 0.86 [0.75-0.92] 0.94 [0.30-1.50] 9.43 [7.24-9.89] 2.61 [2.03-2.87] calf (mm) 0.81 [0.66-0.89] 0.45 [0.20-0.68] 8.09 [7.01-9.27] 1.24 [1.01-1.45] sum of skinfolds (mm) 0.99 [0.97-0.99] 1.86 [1.04-2.68] 2.86 [1.20-3.45] 5.15 [3.14-6.17] physiological tests 5m speed (sec) 0.52 [0.27-0.71] 0.02 [0.01-0.02] 1.94 [1.48-2.40] 0.06 [0.04-0.06] 10m speed (sec) 0.64 [0.42-0.79] 0.09 [0.06-0.09] 4.50 [3.60-5.40] 0.25 [0.10-0.35] 20m speed (sec) 0.90 [0.81-0.94] 0.06 [0.04-0.07] 1.83 [1.20-2.40] 0.16 [0.08-0.24] 40m speed (sec) 0.97 [0.94-0.98] 0.05 [0.03-0.05] 0.95 [0.35-1.55] 0.15 [0.08-0.21] l-run agility (sec) 0.90 [0.82-0.95] 0.11 [0.07-0.15] 1.72 [1.10-2.30] 0.30 [0.19-0.37] vertical jump (cm) 0.93 [0.88-0.96] 0.97 [0.54-1.14] 2.03 [1.03-2.90] 2.70 [1.90-3.46] sit-and-reach (cm) 0.91 [0.84-0.95] 1.42 [1.08-1.57] 17.3 [11.1-19.2] 3.93 [2.89-4.17] 2-kg mbct (m) 0.89 [0.80-0.94] 0.42 [0.20-0.67] 4.48 [3.40-6.10] 1.16 [0.98-1.27] 60-s push-up (sec) 0.93 [0.88-0.96] 2.59 [1.34-3.07] 5.15 [3.12-7.04] 7.17 [6.07-7.98] wall sit leg strength (sec) 0.88 [0.76-0.94] 2.90 [1.87-3.98] 1.98 [0.78-2.94] 8.05 [6.78-9.34] 1-rm back squat (kg) 0.98 [0.96-0.99] 2.08 [1.45-3.45] 2.11 [1.34-2.95] 5.77 [3.57-6.17] 1-rm bench press (kg) 0.98 [0.96-0.99] 2.40 [2.02-2.67] 2.64 [2.54-2.87] 6.64 [5.67-7.12] rhie (sec) 0.79 [0.65-0.89] 1.28 [0.65-1.71] 3.24 [2.10-4.12] 3.55 [3.34-3.98] yo-yo irt (m) 0.72 [0.53-0.84] 42.88 [34.2-67.4] 2.83 [2.09-3.14] 118.87 [101.1-137.9] game skills tests tackling (%) 0.86 [0.74-0.93]* 0.84 [0.35-1.40] 4.75 [2.13-5.13] 2.34 [1.67-3.01] passing ability (au) 0.71 [0.52-0.83] 0.98 [0.30-1.50] 0.84 [0.45-1.23] 2.71 [2.01-3.14] passing accuracy (%) 0.49 [0.22-0.69] 4.66 [3.40-5.70] 5.17 [3.76-7.12] 12.91 [9.03-14.78] catching (au) 0.70 [0.37-0.81] 0.54 [0.10-1.00] 0.72 [0.24-1.03] 1.49 [1.04-2.17] bold indicates low icc values. the units for the sem are the same as the variable. icc, intraclass correlation coefficient; 95% ci,95% confidence interval; sem, standard error of measurement; cv, coefficient of variation; sdc, smallest detectable change; *icc value expresses absolute agreement for average measures; bmi, body mass index, 1-rm, one repetition maximum; yo-yo irt, yo-yo intermittent recovery test; rhie, repeated high intensity exercise; au, arbitrary units; catching, running and catching ability skills test. original research sajsm vol. 33 no. 1 2021 6 given the low reliability, it is possible that the test was relatively easy for u19 rugby players to achieve consistent discriminative performances. to minimise measurement errors, critical test elements, such as the running velocity of the tested and target player and positioning in the passing grid zone for executing the pass, may need careful consideration in future modifications of the test. all scrum tests showed acceptable variability (cv<10%), indicating good agreement between test-retest scores, except for the sit-and-reach test among u19 rugby players. the sitand-reach test showed the greatest variability (cv=17.3%) and paired samples t-test results showed almost statistically significant differences between test-retest assessments (p=0.05). thus, it is possible that the sit-and-reach test lacked standardisation resulting in the observed mean scores between test-retest assessments or more careful standardisation with the warm-up is required before the test is undertaken.with a mean difference between trials of -0.63, the learning effect could have potentially influenced testretest results for the sit-and-reach test. this possibly creates a need for an extra familiarisation trial for the sit-and-reach test in future studies or more than two repeated measures. critical assessment of the study the study utilised a relatively larger sample size than commonly used in similar studies reporting the reliability of anthropometrical and performance tests in rugby. the response and test completion rates were high, eliminating the effect of non-participation bias and missing information on test results. however, the study had some limitations. i. we chose a pragmatic approach involving one age category of participants purposively selected from one school and conducted the study during the competitive rugby season. the residual fatigue from training, especially from previous day and competitive matches, could have affected optimal performance from participants. ii. during the test-retest study, no attempts were made to standardise the timing, type and quantity of food/fluid intake. conclusion among u19 schoolboy rugby players involved in competitive rugby, good to excellent intraclass correlation coefficients were shown for all anthropometric variables. the scrum physiological and game skills tests administered which showed good to excellent relative reliability and acceptable absolute reliability included: 20 m speed, 40 m speed, l-run, vertical jump, 60 s push up, 2 kg medicine ball chest throw, wall sit leg strength, repeated high intensity exercise, one repetition maximum back squat, one repetition maximum bench press, yo-yo intermittent recovery level 1, tackling proficiency, passing ability and running-and-catching ability. all these tests warrant inclusion in the scrum test battery for possible profiling of u19 schoolboy “elite” rugby players during the ‘in-season’ competitive phase provided there is adequate participant familiarisation and test standardisation. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. availability of data and material: all relevant data are within the paper and its supporting information and supplementary files. acknowledgements: the authors would like to acknowledge all the high school male adolescent rugby who participated in this study. the lead author thanks research assistants who collected part or whole data on this project. the zimbabwean ministry of primary and secondary education, the headmasters, school sports directors, and rugby coaches who provided permissions to access schools. further, we would like extend our gratitude to the parents and guardians who gave informed consents for their children to participate in the study. also, the authors thank rugby expert coaches who rated the participants on game-specific skills, the anthropometrist who performed the skinfold measures, former u19 adolescent rugby players used as ’dummy’ players for the assessment of game specific skills, and content experts for validating the data collection instruments. author contributions: mc, bs-e and gf contributed to conception, design of the study, data analysis and interpretation. mc also conducted the literature review, recruited and trained research assistants and participants with variable assistance coming from other people acknowledged in the acknowledgment section. mc supervised the data collection and did the analysis. mc drafted the manuscript for publication and acted as the corresponding author. bs-e, ct, jmd and nsm performed critical revision of the manuscript, and provided extensive revisions prior to submission to the journal for review. all the authors read and approved the final version of the manuscript. references 1. jones b, weaving d, tee j, et al. bigger, stronger, faster, fitter: the differences in physical qualities of school and academy rugby union players. j sports sci 2018; 36(21): 2399-2404. 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[doi: 10.1260/1747-9541.10.5.949] https://dx.doi.org/10.1136%2fbmjsem-2017-000281 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1002/(sici)1097-0258(19980115)17:1%3c101::aid-sim727%3e3.0.co;2-e file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1002/(sici)1097-0258(19980115)17:1%3c101::aid-sim727%3e3.0.co;2-e file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1080/24733938.2017.1411603 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1055/a-0637-2094 doi:o10.1016/j.jclinepi.2006.03.012 http://dx.doi.org/10.1519/jsc.0000000000002280 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1016/j.jclinepi.2005.10.015 https://dx.doi.org/10.1016%2fj.jcm.2016.02.012 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1519/jsc.000000000000123 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1519/jsc.000000000000123 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1519/jsc.0b013e31815ef700 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1080/026404198366326 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1177/2059799116672875 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1260/1747-9541.10.5.949 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1260/1747-9541.10.5.949 sajsm vol. 28 no. 1 2016 33 original research case study an atypical presentation of myositis ossificans m bultheel,1,2 md, m med (sports med); jh kirby,1 mbchb, msc (sports med); jt viljoen,1 bsc (physio), mphil (exercise sci); pl viviers,1 mbchb, m med sc, msc (sports med), facsm 1 campus health service and the centre for human performances sciences, stellenbosch university, south africa 2 department of physical medicine and rehabilitation, catholic university of leuven, belgium corresponding author: pl viviers (plv@sun.ac.za) in the following case study an atypical presentation of myositis ossificans (mo) in the superior anterolateral thigh of a young soccer player is discussed. this case demonstrates that mo can present without obvious history of trauma, which makes the diagnosis of this condition more challenging. the most important differential diagnosis is malignant osteosarcoma or soft-tissue sarcoma, which usually presents without trauma. additionally both pathologies typically occur in the same population. keywords: case report, ossification, osteosarcoma s afr j sports med 2016;28(1):33-34. doi:10.17159/2078-516x/2016/v28i1a465 myositis ossificans (mo) is defined as a localised formation of heterotopic non-neoplastic bone in muscle or soft tissue.[1] it usually presents as a complication of traumatic muscle injury and thus is most likely to develop in high-risk sites of injury such as the quadriceps and biceps muscle. it is most readily seen in adolescent and young adult men as a result of sport-related blunt trauma. a 21-year-old male recreational soccer player presents with a three-week history of right hip pain during kicking, sprinting and climbing stairs, preceded by eight months of stiffness. he noticed a hard lump in the upper thigh on which he unsuccessfully performed self-facilitated massage to release the area. he reports previous minor muscle strains in the area but no direct blunt trauma. there is no pain at rest or at night, nor does he report weight loss, night sweating or generalised malaise. moreover, his medical and family history is insignificant. clinically, this appears to be a healthy young man with normal gait and full range of motion of the hips. however, resisted hip flexion and abduction as well as the thomas test reproduce pain. the nodule feels firm and is not tender upon palpation. ultrasound demonstrates a hyper reflective peripheral rim suggesting calcification of the nodule. two areas of ossification were reported following plain radiographs, one in the soft tissues posterior to the hip joint and the other over the lateral aspect of the superior acetabular rim (see figure 1, a & b). furthermore, areas of central lucency were identified and no connection was found between the mass and the femur. considering the patient’s history and mature aspect of the lesion upon imaging the diagnosis of end stage mo was made. conservative treatment with physiotherapy failed to resolve the patient’s symptoms and there was functional impairment with exercise, hence the calcification was removed surgically. since then the patient has recovered to his previous level of participation in sport, however he does occasionally report pain and stiffness during high intensity sporting activities. to date (20 months post-surgery) no reappearance has been reported. fig. 1 anteroposterior (a) and frog-leg lateral (b) radiographs of the right hip showing mature heterotopic bone in the right upper leg. discussion mo is a known complication of muscle injury where calcification proceeds to ossification in muscle or soft tissue.[2] the exact aetiology is still unknown and several theories have been proposed. it has been hypothesised that rapidly proliferating mesenchymal cells, in the presence of localised tissue anoxia, ultimately differentiate into boneforming cells and osteoblasts, producing ectopic bone and cartilage. in addition, muscle damage leads to prostaglandin synthesis, which attracts inflammatory cells to the site of injury, fostering the formation of  mo.[3] an alternative theory is that mechanical injury can cause the osteoblast-containing periosteum to be pushed into the muscle which results in ectopic calcification.[4,5] the incidence of mo after muscle contusion has not been well documented, but has been reported to be 9-17%. the occurrence is thought to be related to the severity of injury and is higher in males 30-40 years old.[6] the physical signs suggesting impending mo are localised tenderness and swelling, a palpable mass and loss of flexibility.[5] differential diagnosis may include a muscle haematoma, abscess and malignant primary or secondary soft tissue tumours. the most important differential diagnosis is extra-skeletal osteosarcoma, which has similar clinical and pathological characteristics.[6-8] various imaging techniques are available to evaluate the presence and progression of mo including musculoskeletal ultrasound (msu), radiography, computed tomography, magnetic resonance imaging and skeletal scintigraphy. it is important to note that the radiologic features evolve as the lesion matures. msu is a sensitive modality and may have the capability to detect early phases of mo approximately two weeks prior to radiographic evidence.[5] msu can also monitor progression throughout the course of mo where peripheral rim-like calcification and sheet-like or lamellar calcification are mailto:plv@sun.ac.za http://dx.doi.org/10.17159/2078-516x/2016/v28i1a465 34 sajsm vol. 28 no. 1 2016 original research very suggestive of mo. calcification that is more centrally located is nonspecific, and may be seen with a soft tissue tumour. msu can also be used to guide surgical removal of a lesion as total reflection of the msu beam from the peripheral rim indicates that the lesion is mature. conversely reappearance is more likely if a lesion is removed when it is metabolically active (not fully reflective).[6,9] the most important diagnostic feature on x-rays is the zoning pattern of peripheral maturation, indicating that the lesion is benign. the finding of this radiopenic centre and the absence of connection to the adjacent bone, the so called cleavage plane, further aids in the differentiation of mo from malignant lesions of bone.[9] management of early mo consists of rest, ice, compression and elevation followed by physiotherapy to regain strength, proprioception and flexibility. during this stage aggressive stretching should be avoided.[3] indomethacin, a non-steroidal antiinflammatory has been proposed to inhibit further formation of new bone.[7] the natural history of mo is of benign nature and it may even regress after several months. surgical intervention is thus only indicated when there is functional limitation, persistence of pain after the inflammatory phase, neurovascular compromise or severe disfigurement. it should only be performed on mature heterotopic bone. however even during the mature phase there is a risk of reoccurrence following resection.[7] conclusion this case report demonstrates that mo can have an insidious onset without a clear history of blunt traumatic muscle injury. therefore diagnosis can be more challenging, especially when differentiating mo from a malignant lesion such as an osteosarcoma. understanding the pathophysiological development of mo, namely its typical peripheral to central ossification process is imperative in making the correct diagnosis. treatment is usually conservative and involves physiotherapy and anti-inflammatories. large lesions with functional limitations may be managed surgically. funding: none. conflict of interest: none. references 1. gindele a, schwamborn d, tsironis k, et al. myositis ossificans traumatica in young children: report of three case and review of literature. pediatr radiol 2000;30:451-459. [http://dx.doi.org/10.1007/s002479900168] 2. yazici m, etensel b, gürsoy h, et al. nontraumatic myositis ossificans with an unusual location: case report. j pediatr surg 2002;1621-1622. [http://dx.doi. org/10.1053/jpsu.2002.36196] pmid: 12407551. 3. busell p, coco v, notarnicola a, et al. shock waves in the treatment of posttraumatic myositis ossificans. ultrasound med biol 2010;36:397-409. [http://dx.doi. org/10.1016/j.ultrasmedbio.2009.11.007] 4. kim sw, choi jh. myositis ossificans in psoas muscle after lumbar spine fracture. spine 2009;34:367-370. [http://dx.doi.org/10.1097/brs.0b013e31819b30bf ] 5. king, jb. post-traumatic ectopic calcification in the muscles of athletes: a review. br j sports med 1998;32:287-290. [http://dx.doi.org/10.1136/bjsm.32.4.287] pmid: 986397. 6. yochum a, reckelhoff k, kaeser m. ultrasonography and radiography to identify early post traumatic myosistis ossificans in an 18-year-old male: a case report. j chiropr med 2015;13:134-138. [http://dx.doi.org/10.1016/j.jcm.2014.06.004] 7. lau j, hartin cw jr, ozgediz de. myositis ossificans requires multiple diagnostic modalities. j pediatr surg 2012;47:1763-1766. [http://dx.doi.org/10.1016/j. jpedsurg.2012.05.009] pmid: 22974621. 8. el bardouni a, boufettal m, zouaidia f, et al. non-traumatic myositis ossificans circumscripta: a diagnosis trap. j clin orthop trauma 2014;5:261-265. [http:// dx.doi.org/10.1016/j.jcot.2014.09.005] pmid: 25983509. 9. parikh j, hyare h, saifuddin a. the imaging features of post-traumatic myositis ossificans, with emphasis on mri. clin radiol 2002;57:1058-1066. [http://dx.doi. org/10.1053/crad.2002.1120] pmid: 12475528. http://dx.doi.org/10.1007/s002479900168 http://dx.doi.org/10.1053/jpsu.2002.36196 http://dx.doi.org/10.1053/jpsu.2002.36196 http://dx.doi.org/10.1016/j.ultrasmedbio.2009.11.007 http://dx.doi.org/10.1016/j.ultrasmedbio.2009.11.007 http://dx.doi.org/10.1097/brs.0b013e31819b30bf http://dx.doi.org/10.1136/bjsm.32.4.287 http://dx.doi.org/10.1016/j.jcm.2014.06.004 http://dx.doi.org/10.1016/j.jpedsurg.2012.05.009 http://dx.doi.org/10.1016/j.jpedsurg.2012.05.009 http://dx.doi.org/10.1016/j.jcot.2014.09.005 http://dx.doi.org/10.1016/j.jcot.2014.09.005 http://dx.doi.org/10.1053/crad.2002.1120 http://dx.doi.org/10.1053/crad.2002.1120 _goback sajsm 595 (commentarty).indd short report 1 sajsm vol. 35 no. 1 2023 creative commons attribution 4.0 (cc by 4.0) international license university and stakeholder partnerships to innovate in sport – the development of the south african cricketers’ association (saca) career transition screening tool s hendricks,1,2,3 phd; jp van wyk,4 pg dip sports management; b player,4 sac dip; r schlebusch,4,5 pgce dip 1 division of physiological sciences, department of human biology, faculty of health sciences, university of cape town, cape town, south africa 2 health through physical activity, lifestyle and sport (hpals) research centre, department of human biology, faculty of health sciences, university of cape town, cape town, south africa 3 institute for sport, physical activity and leisure, leeds beckett university, leeds, united kingdom 4 south african cricketers’ association, cape town, south africa 5 sportsthink 360, claremont, cape town, south africa corresponding author: s hendricks (sharief.hendricks01@gmail.com) the value of university–stakeholder partnerships innovation can be considered the successful implementation of a novel idea that creates value for some or all of its stakeholders. to be innovative and solve challenges that will benefit society, universities are strongly encouraged to engage and build partnerships with external constituencies, stakeholders and communities. in sport, the value and mutual benefit of university (researchers) –stakeholder partnerships have been wellrecognised – for example, from the perspective of the university, stakeholder partnerships help to guide research questions and offer direct access to athletes and policymakers. from the stakeholder perspective, university partnerships may offer expertise and resources which otherwise may not have been accessible. considering these benefits, frameworks to enhance university-stakeholder partnerships in sport have been proposed.[1] in many cases, while a key focus of the university– stakeholder partnerships is research, several internal reports and tools are also produced. typically though, only the research findings of a partnership are shared and published in the literature. in other words, the literature rarely describes the collaborative process between researchers and stakeholders in the development of tools that address the specific needs of the stakeholders. cricket and its unique set of challenges according to the international cricket council global market research report, cricket is one of the world’s most popular team sports, with 106 member countries, over 300 million male an d female participants, and more than one billion fans. it has been argued that cricket has a unique set of challenges compared to other team sports. these include: how performance is appraised by primarily using individual game statistics (for example, run s scored), the different formats of the game (5-day tests, 50 overs (1-days) and 20 overs (t20), and extensive travel and time away from home. for example, an international cricket tour may last up to two months and require playing all formats of the game. [2] career transitioning in sport as the demand on players in professional cricket has increased over the years, so has the interest in their career transitioning. that is, how do professional cricketers manage stressors created by changes (or non-changes) throughout their playing career, and how do systems best support these players? most of the work on career transitioning in sport, including cricket, focuses on players transitioning out of the sport (i.e. retiring athletes). [3] more recently, coping within career transitioning (for example, progressing from youth to senior level, or semi -professional to professional level) has also been recognised as a key contributing factor to the long-term health and well-being of the player.[3] at the same time, factors that contribute to a successful career transition (improved adaptation and management of transition and greater post-transition well-being) have also been identified.[4] one way a player can improve the likelihood of a successful transition is to plan for the career transition and engage in it voluntarily.[4] player associations and university partnerships player associations are organisations that represent the needs and interests of players within the respective sport and play a key role in the ecosystem of professional sport. one of the primary objectives of a player association is to promote and enhance the general health and well-being of its members (i.e. the players). in south africa, the south african cricketers’ association (saca) fulfils this objective for all professional cricketers. in 2016, saca and the university of cape town (uct) established a partnership to (i) conduct novel research on professional cricketers and (ii) ensure saca programmes and initiatives are informed by said research and/or the currently available literature. from a university perspective, the partnership signifies a high degree of engaged scholarship for staff and students and the opportunity to produce highin sports, the value and mutual benefit of university–stakeholder partnerships have been well-recognised. it has been argued that cricket has a unique set of challenges compared to other team sports. in 2016, the south african cricketers’ association (saca) and the university of cape town established a partnership to (i) conduct novel research on professional cricketers and (ii) ensure saca programmes and initiatives are informed by said research and/or the currently available literature. as the demand on professional cricketers has increased, so has the interest in their career transitioning. that is, how do professional cricketers manage stressors created by changes (or non-changes) throughout their playing careers? to help identify gaps for intervention as a cricketer transitions through their professional career, the purpose of this short report is to describe how a university–stakeholder partnership developed a career transitioning screening tool for professional cricketers in south africa. keywords: player welfare, athlete transitioning, cricket, innovation, stakeholder engagement, south africa s afr j sports med 2023;35:1-3. doi: 10.17159/2078-516x/2023/v35i1a15218 mailto:sharief.hendricks01@gmail.com http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15218 https://orcid.org/0000-0002-3416-6266 https://orcid.org/0000-0003-2753-0194 https://orcid.org/0000-0002-4019-5039 https://orcid.org/0000-0001-8414-0139 short report sajsm vol. 35 no. 1 2023 2 impactful research. to conduct ongoing research, uct approved a saca research ethics database in 2017. the first project of this university-stakeholder partnership was related to the mental health of professional cricketers.[2, 5] subsequent to this project, saca sought to improve players’ career transitioning both within and out of professional cricket. specifically, saca required a screening tool that would help them to identify gaps for intervention as the cricketer transitions through their career. using such a screening tool, saca would work with the cricketer to help prepare and plan for any forthcoming career transition. the purpose of this short report is to describe how saca and the uct partnered to develop a career transitioning screening tool for professional cricketers in south africa. stakeholder criteria and context south africa has 17 professional cricket teams (proteas men and women, eight division 1 and seven division 2) teams. saca allocates each team a player development manager (pdm), who supports the cricketer throughout their professional playing career and for a period after retiring. the objective of the pdm is to assist players with all non-cricket-related aspects; so players are well-rounded individuals and prepared for a life after a professional cricket career. for example, assisting cricketers to continue their studies while playing cricket. pdms meet with all players regularly; however, given the scheduling demands of cricket, pdms may be meeting under time constraints. some players may not even be aware they are going through a withincareer transition, rendering conversations about it difficult. in 2019, considering the role of the pdm and the need to improve players’ career transitioning (both within and out of professional cricket), saca proposed the development of a screening tool to raise career transitioning awareness among its players. more specifically, to assist pdms in identifying whether a player is experiencing a career transition or not, and whether an intervention is required, i.e. linking the player to a service. during the early stages of development, it was agreed that the best form for the tool would be a screening questionnaire. a screening questionnaire would be easy to administer to teams and completing it would be quick and straightforward. pdms would then use the player’s questionnaire responses to initiate the career transition conversation and link the player to the appropriate service. the main criterion during the development of the screening questionnaire though was that it had to be based on career transitioning literature. two versions of the screening tool were developed – one for players experiencing (or about to experience) within career transitioning and one for players approaching retirement. career transitioning screening tool development park et al. [6] conducted a systematic review of career transitioning in sport and identified 15 factors associated with career transition quality. of these factors, we deduced three will be incorporated into the screening tool as it fell within saca’s remit: these were career/personal development, educational status and financial status. athletic identity was also the strongest factor associated with transition quality,[6] and it was decided questions on athletic identity should be included in the screening tool. keeping in mind the criteria to have a quick and straightforward tool to complete, the within-career – ‘check-in’(appendix 1) – career transition screening tool was focused on 13 questions based on previously published scales and questionnaires – the athletic identity measurement scale (5 questions: 1 on self-identity (q1), 2 on exclusivity (q2 and q3), 1 on negative affectivity (q4) and 1 on social identity (q5),[6] the perceived available support in sport questionnaire (the pass-q) (1 question with four subsections, namely, resources for financial advice and planning, resources for emotional support, resources for career advice, resources for study advice (q9),[7] and questions on transition preparedness (q10-q13). questions 6-8 related to career transitioning awareness and asked cricketers if they have ever experienced a career transition (q6), currently experiencing a career transition (q7) or if they foresee a career transition (out of cricket) in the next 12 months (q8). the tool for player s approaching retirement – ‘prepare for landing’ (appendix 2) – focused on 22 questions 10 questions from the ‘check-in’ tool, with an additional 12 questions based on the athletes retirement decision inventory(ardi).[8] questions 11-15 were anti-pull factors, q16-18 pull factors, q19-q20 anti-push factors, and q21q22 were push factors. both career transition screening tools also included a section for pdm notes and potential actions. after the screening tools were finalised, both questionnaires were reviewed by bp, a past player and current pdm, to ensure each question was clear and understandable. both the ‘check -in’ and ‘prepare for landing’ career transition screening tools are currently available to all saca pdms to use when required. at this stage, whether screening should be mandatory for all players is an ongoing discussion. conclusion the purpose of this short report was to describe how a university–stakeholder partnership developed screening tools that help to identify gaps for intervention as a cricketer transitions through their professional career. a key strength of the screening tool is that it was based on the current literature on career transitioning and uses established, validated questionnaires, while at the same time fulfilling the criteria of the stakeholder. that is the screening tools needed to be quick and straightforward to complete considering the context in which they would be implemented (time-constrained pdm-player meetings). it is worth noting that the career transition screening tools were developed specifically for the needs and context of saca. as such, while the university–stakeholder partnership approach described here can most certainly be used in other sports and stakeholder(s) settings, the career transition screening tools themselves may not be as generalisable, and therefore the screening tools may require adapting when implemented in other sports settings. conflicts of interest and source of funding: jpvw, bp and rs are employed by the south african cricketers’ association. there was no source of funding. author contributions: sh drafted the manuscript, and jpvw, bp and rs provided input. all authors contributed to the final version. references 1. hendricks s. rethinking innovation and the role of stakeholder engagement in sport and exercise medicine. bmj open sport exerc med 2021;7(2):e001009. [doi: 10.1136/bmjsem-2020-001009] [pmid: 34123408] 2. hendricks s, amino n, van wyk j, gouttenbarge v, mellalieu s, schlebusch r. inside edge–prevalence and factors associated with symptoms of anxiety/depression in professional cricketers. res short report 3 sajsm vol. 35 no. 1 2023 sport med 2022:1-13. [doi: 10.1080/15438627.2022.2139619] [pmid: 36284499] 3. stambulova nb, ryba tv, henriksen k. career development and transitions of athletes: the international society of sport psychology position stand revisited. int j sport exerc psychol 2021;19(4):524550. [doi: 10.1080/1612197x.2020.1737836] 4. kuettel a, boyle e, schmid j. factors contributing to the quality of the transition out of elite sports in swiss, danish, and polish athletes. psychol sport exerc 2017;29:27-39. [doi: 10.1016/j.psychsport.2016.11.008] 5. armino n, gouttebarge v, mellalieu s, schlebusch r, van wyk j, hendricks s. anxiety and depression in athletes assessed using the 12-item general health questionnaire (ghq-12) a systematic scoping review. s afr j sports med 2021;33(1):1-13. [doi: 10.17159/2078-516x/2021/v33i1a10679] 6. park s, lavallee d, tod d. athletes' career transition out of sport: a systematic review. int rev sport exerc psychol 2013;6(1):22-53. [doi: 10.1080/1750984x.2012.687053] 7. freeman p, coffee p, rees t. the pass-q: the perceived available support in sport questionnaire. j sport exerc psychol 2011;33(1):54-74. [doi: 10.1123/jsep.33.1.54] [pmid: 21451171] 8. fernandez a, stephan y, fouquereau e. assessing reasons for sports career termination: development of the athletes' retirement decision inventory (ardi). psych sport exercise 2006;7(4):407-421. [doi: 10.1016/j.psychsport.2005.11.001] sajsm vol 19 no. 5 2007 117 introduction overweight and obesity in children is becoming a global problem, with an increasing prevalence among children of all age groups. 54 south african children are no exception, with a prevalence of overweight and obesity of 14.0% and 3.2% in boys, respectively. in girls between the ages of 6 and 13 years, 17.9% are overweight and a further 4.9% are obese. 5 studies performed on small, local and regional samples of south african children suggest that the relatively high prevalence of obesity may be attributed in part to a decline in habitual physical activity, an increase in inactivity and sedentary lifestyles, associated with increasing urbanisation and improved socioeconomic status within households (assessed by the reliance on motorised transport). 8,13,19,27,32 indeed, it has been reported that children with lower levels of lean body mass and higher body mass index (bmi) are spending more time watching television or using computers, instead of engaging in physical activity, sports or play. 3,12,15,27,39,53 moreover, a national study undertaken in south african adolescents suggests that only 54.3% have physical education classes on their timetable, and of these only 52.8% engage in vigorous activity during class. 33 physical activity in childhood tracks into adulthood, thereby emphasising the need to address the lack of physical activity in children and youth. 10,20,43,45 an accurate measurement of physical activity is fundamental to our understanding of the relationships original research article validity and reliability of a physical activity/inactivity questionnaire in south african primary schoolgirls abstract objective. we sought to determine the validity and reliability of a self-report physical activity questionnaire (paq) measuring physical activity/inactivity in south african schoolgirls of different ethnic origins. methods. construct validity of the paq was tested against physical activity energy expenditure estimated from an activitygram and inactivity from reported television programme viewing in 332 girls (ages 9 12 yrs, grades 4 5). body composition (who bmi percentiles and percentage body fat) was used as an indirect measure of validity for the paq. test-retest reliability of the paq was assessed in a convenience sample of 14 girls. results. weak but significant associations were found between the body composition and paq-derived total energy expenditure (r=-0.18; p<0.05 for percentage body fat; r=-0.17; p<0.01 for who bmi percentiles) and inactivity (r=0.35; p<0.001 for percentage body fat; r=0.23; p<0.001 for who bmi percentiles). positive associations were found between moderate and vigorous energy expenditure by paq and the same intensity activities by activitygram (r=0.19; p<0.001 and r=0.26; p< 0.001, respectively). further, the television viewing time reported correspondence: professor estelle v lambert uct/mrc research unit for exercise science and sports medicine department of human biology faculty of health sciences university of cape town po box 115 newlands 7725 tel/fax: (021) 650-4571/686-7530 e-mail: vicki.lambert@uct.ac.za z j mciza (bsc dietetics)1 j h goedecke (phd)1,2 e v lambert (phd)1 1 uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town 2 medical research council of south africa, parow, cape town by paq was significantly positively related to the number of programmes noted from the television programme list. only total energy expended while partaking in structured school sports showed good test-retest reliability (r=0.80; p<0.05). conclusions. our results showed that the paq may provide some reasonable insights into levels of physical inactivity and activity in south african primary schoolgirls. however, additional studies are required using objective measures of physical activity, such as pedometry or accelerometry, to better understand the utility of the paq for children. pg117-124.indd 117 1/11/08 12:24:28 pm 118 sajsm vol 19 no. 5 2007 between physical activity, obesity and health. 15,41 there are a myriad of international studies using self-report questionnaires (including both previous-day and 7day physical activity recalls) in children in which both construct and criterion validity and reliability have been tested. 1,4,18,37,40,42,44,52 ideally, an instrument should capture all aspects of physical activity including physical activity during and after school as well as sedentary behaviour, and be able to differentiate between weekday and weekend physical activity. 24 however, there is a lack of locally validated instruments for this purpose in south africa, and as a result, a paucity of data concerning the prevalence of physical activity in south african children. therefore, the main aim of our study was to validate a self-report method of estimating physical activity/ inactivity levels in south african children. the method needed to be culturally sensitive, cost effective, and convenient to administer in larger groups of children, as part of formative assessment for intervention studies to increase physical activity. for the purpose of this study, a physical activity questionnaire (epaq2), used to assess physical activity in european adolescents, 49 was modified and adapted to estimate physical activity/inactivity in a group of preadolescent south african children of different ethnic origins. 28 construct validity and reliability of this modified and adapted physical activity questionnaire (paq) were then tested against an activitygram and a television programme list, and the body composition of the girls was used as an indirect measure of validity of the paq. methods subjects this validation study was undertaken as part of a larger project in which diet and physical activity, knowledge, attitudes, beliefs and health behaviours in south african women and their daughters were evaluated. .26 girls (ages 9 12 yrs, grades 4 5, n=332) were recruited from 15 primary schools in the cape town metropole area, sampled on the basis of divergent socioeconomic status (represented by low, middle and high socioeconomic strata). thirty per cent of girls interviewed were from schools within the highest socioeconomic strata, 49% from the middle socioeconomic strata and 21% from the lowest strata. the response rate for the girls was 89%. the final sample comprised 32% black girls, 34% mixed ancestry girls and 34% white girls. a convenient sample of 14 girls with similar characteristics to the main sample was randomly selected, and the questionnaire was re-administered 1 week later in an effort to perform the test-retest analysis (reliability) of the questionnaire. body composition measures as an indirect measure of validity of the paq, body composition was measured using bmi, world health organization body mass index (who bmi) percentiles, as well as percentage body fat. 3,16,17 bmi was calculated as kg.m -2 (body weight was assessed in light clothing, without shoes, and recorded to the nearest 0.5 kg using a calibrated digital scale (tanita hd-309, tanita corporation of america inc, usa). body weight was then divided by the height squared, which was measured to the nearest 0.5 cm). who bmi percentiles were also determined. 9 triceps, biceps, subscapular and supra-iliac skinfold thicknesses were measured using calibrated skinfold calipers (harpenden, assist creative resources ltd, uk), and recorded to the nearest 0.1 mm. percentage body fat was calculated using standard equations. 11 instruments physical activity/inactivity over a period of 7 days was assessed using a paq adapted from the epaq2, 49 which had previously been successfully used in a younger group of south african children (7 9-yr-olds). 28 the paq included questions on physical education classes, formal and informal activities, activities done at school, activities done out of school in sports clubs or gyms, as well as just playing games at home. the girls were also required to report on hours spent walking to and from school, or just simply sitting and using a computer or watching television. the paq was administered by trained interviewers, who conducted the interviews using the language of choice for each of the 332 girls. the paq was then re-administered a week later on a convenience sample of 14 girls. the total minutes spent doing physical activity as measured by the paq were converted to energy expenditure in the form of met min.week -1 , by multiplying the minutes per week by different levels of intensities. these levels of intensity were defined as: resting (1 mets), light (3.0 mets), moderate (4.5 mets) and vigorous (7.5 mets). 2,22 physical inactivity was quantified on the basis of television or computer time per week. furthermore, girls completed the activitygram developed by the cooper institute (dallas, texas, usa) 51 in which they were required to rate the intensity of their activities during 30-minute time intervals throughout the day. they were also asked to mark the television programmes watched from a pre-prepared list, as well as the frequency and duration of watching television in an average week. these results were based on a television programme list, which included the most commonly watched programmes by south african children. statistical analysis all data were analysed using statistica version 7: (statsoft inc, tulsa, ok, usa version 7.0). data were reported as means ± standard deviations and p<0.05 was considered statistically significant. where data were not normally distributed, medians, 25th and 75th quartiles were reported and non-parametric analyses were performed. construct validity was determined using spearman’s rank-order correlations comparing results of the activitygram with those of the pg117-124.indd 118 1/11/08 12:24:29 pm sajsm vol 19 no. 5 2007 119 self-report paq. furthermore, the test-retest reliability was also evaluated using spearman’s rank correlation. analysis of variance or kruskal wallis tests were performed to determine the differences in physical activity/inactivity between the three ethnic groups of girls. where appropriate, scheffe’s post-hoc tests were used to evaluate between-group differences. in addition, between-group differences were adjusted for differences in socioeconomic status on the basis of housing density and asset index, using analysis of covariance. chi-square analysis was used to determine ethnic differences in sociodemographic characteristics of the girls, as well as the categorical variables relating to physical activity derived from the paq. results participants’ characteristics detailed characteristics of the participants have been reported previously. 26 in brief, 332 girls participated in this study. the average age of the girls was 10.5±0.9, 10.1±0.7 and 10.0±0.8 years, p<0.001, for black, mixed ancestry and white girls, respectively. mean who bmi percentile was significantly higher in the white girls, compared with those of mixed ancestry and of african descent (61±28 v. 59±30 and 57±31 percentile, p<0.05, respectively). however, there were no significant differences in the body weight, height and body fatness between the girls. black girls presented with significantly lower socioeconomic status based on the housing density and asset index, than the other groups of girls (p<0.001). in addition, fewer black girls reported having television (77 v. 99 and 98%, p<0.001, respectively) or computers (16 v. 77 and 87%, p<0.001, respectively) in their households, as well as having physical education offered at their schools (63 v. 88 and 93%, p<0.001, respectively) compared with mixed ancestry and white girls. the characteristics of the sub-group sampled for test-retest reliability (n=14) were not significantly different than those of the larger group (n=332) (data not shown). body composition as an indirect measure of paq validity body composition (who bmi percentiles and percentage body fatness) of the girls was used as an indirect measure of the validity of paq-derived measures of energy expenditure and inactivity (table i). weak but significant inverse associations were found between the girls’ percentage body fat and total energy expenditure and inactivity by paq. furthermore, there was an inverse association between girls’ who bmi percentiles and moderate energy expenditure derived from walking to and from school. construct validity of paq against the activitygram and television programme list construct validity of the paq-derived measures of energy expenditure and inactivity against energy expenditure derived from the activitygram and from the television programme list are presented in table ii. a significant positive association was found between the time spent watching television, recorded in the paq, and the number of television programmes selected from the television list. weak but significant positive associations were also found between moderate and vigorous energy expenditure by the paq and the same intensity activities recorded using the activitygram. however, no significant associations were observed in overall paq derived energy expenditure and total energy expenditure estimated using an activitygram. test-retest reliability of the paq we were only able to demonstrate significant test-retest reliability for total energy expenditure (met min.week -1 ) for the structured school sports (r=0.79, p<0.05). the remainder of table i. indirect validity of the physical activity questionnaire (paq)-derived measures of energy expenditure and inactivity against body composition of the girls spearman’s ρ p who bmi percentiles v. overall energy expenditure -0.18 <0.05 percentage body fat v. overall energy expenditure -0.17 <0.01 who bmi percentiles v. moderate energy expenditure (walking to and from school) -0.17 <0.01 who bmi percentiles v. overall television time 0.23 <0.001 percentage body fat v. overall television time 0.35 <0.001 table ii. construct validity of the physical activity questionnaire (paq)-derived measures of energy expenditure and inactivity against the activitygram and television programme list spearman’s ρ p moderate energy expenditure by the paq v. moderate energy expenditure by an activitygram 0.19 <0.001 vigorous energy expenditure by the paq v. vigorous energy expenditure by an activitygram 0.26 <0.001 overall energy expenditure by the paq v. total energy expenditure by an activitygram 0.02 0.78 television time by the paq v. number of programmes watched by the television programme list 0.19 <0.001 pg117-124.indd 119 1/11/08 12:24:30 pm 120 sajsm vol 19 no. 5 2007 the paq physical activity constructs did not show good test-retest reliability over a period of 7 days (table iii). ethnic differences in energy expenditure ethnic differences in energy expenditure estimated using the paq and activitygram are presented in table iv. although none of the black girls participated in physical activity outside of school in sports clubs, they reported expending more overall energy per week than white and mixed ancestry girls (p<0.001). most of this energy was expended while partaking in moderate physical activity at school (p<0.001) and informal game activities at home (p<0.001). there was an inverse association between socioeconomic status (presented by housing density and asset index) and energy expenditure (r=-0.18, p<0.05 and r=-0.26, p<0.05 respectively). black girls expended more total energy than mixed ancestry and white girls even after adjusting for the confounding factors of socioeconomic status based on both the housing density and asset index (both p values <0.05) (data not shown). in addition, the majority of black girls reported expending more energy by walking to and from school than mixed ancestry and white girls (73 v. 16 and 11%, respectively, p<0.001). however, no significant ethnic differences were found in energy expenditure generated using the activitygram even after adjusting for socioeconomic status. only ethnic differences in vigorous activities tended towards significance (p=0.057). ethnic differences in inactivity table v presents the time spent by the girls using technology-based entertainment (watching television and using a computer) each day. using the paq, we found that overall, mixed ancestry girls were more likely to use technology-based entertainment than white and black girls (p<0.05). however, white girls spent significantly more time watching television than mixed ancestry and black girls (p<0.05). white girls spent most of this time on weekends (p<0.05). ethnic differences in television time remained the same even after adjusting for socioeconomic status based on housing density. further, the girls who watched 3 or more hours of television each day had greater mean who bmi percentiles than those who watched less than 3 hours of television per day (61.2±29.0 v. 54.4±30.5, percentiles, p<0.05 (fig. 1)). however, no ethnic differences were found. the relationship between who bmi percentiles and television hours was unaltered by socioeconomic status (as presented by both the housing density and asset index scores). the table iv. girls’ energy expenditure according to ethnicity measured by the physical activity questionnaire (paq) and the activitygram level of activity black mixed ancestry white 32% (n=105) 34% (n=113) 34% (n=114) paq school (met min/week) moderate 360(0;1 800) * 0(0;720) * † 720(0;1 080) † vigorous 0(0;0)* 0(0;0) † 0(0;480)* † total 720(0;1 800)* † 480(0;1 080)* 810(420;1 620) † paq overall (met min/week) moderate 720(0;2 520) 540(0;1 080)* 720(360;1 440)* vigorous 0(0;960)* 120(0;960) 480(0;1 440)* total 2 528(1 080;4 950)** 1 295(660;2 400)** † 2 106(1 040;3 100) † activitygram (met min/week) moderate 3 360(840;4 200) 1 680(0;5 040) 0(2 520;5 040) vigorous 0(0;3 360) 0(0;0) 0(0;0) total 7 560(4 830;10 500) 6 300(3 360;9 660) 6 20(3 360;11 130) values are in median (± interquartile range). moderate (≤ 6 met min / week), vigorous (≥ 6 met min / week). matching superscript symbols represent groups that are significantly different to each other,*,† = p<0.05 and ** = p<0.001. table iii. test-retest reliability of the energy expenditure and inactivity measured by the physical activity questionnaire (paq) spearman’s ρ p school sports (minutes/week) 0.79 <0.05 home games (minutes/week) -0.50 0.67 club/gym sport (minutes/week) -0.37 0.30 television time (minutes/week) 0.27 0.35 moderate activity (met minutes/day) 0.06 0.27 vigorous activity (met minutes/day) -0.33 0.63 overall activity (met minutes/day) -0.20 0.30 pg117-124.indd 120 1/11/08 12:24:30 pm sajsm vol 19 no. 5 2007 121 time spent watching television each day decreased with a decrease in socioeconomic status based on the housing density (r=-0.12, p<0.05). significant ethnic differences generated using the television programme list are also presented in table v (p<0.05). these differences also remained unaltered even after adjusting for socioeconomic status (p<0.05). discussion energy expenditure in the form of physical activity is associated with well-established health benefits, 14,25,30 which increase with an increase in frequency, duration and intensity of exercise. 47 however, a more detailed understanding of the required exercise dosage and the extent of resulting health benefits is required, particularly in children where inactivity and the prevalence of obesity are increasing at an alarming rate. 5 this may only be achieved through the development of standardised instruments that record the low-intensity activities typical of sedentary societies, and ascribe consistent biological meaning to terms such as light, moderate, and heavy exercise. 41, 45 however, there are few validated instruments that measure physical activity and inactivity that are pertinent to multicultural and developing countries such as south africa, where there is a high prevalence of overweight and obesity in children. 5 in the present study, an adapted version of a paq previously used in south african children 28 and european adolescents 49 demonstrated only modest indirect criterion validity, concurrent and construct validity in south african primary schoolgirls. based on evidence suggesting an association between body composition and physical activity/inactivity, 3,16,17 we used measures of body fatness and who bmi percentiles as indirect measures of validity for paq-derived energy expenditure and inactivity. in this study, body fatness and who bmi percentiles were lower in those girls with higher overall energy expenditure (generated by partaking in sports or play, and walking to and from school), and those girls who spent less time watching television. these results are in agreement with other local and international studies. 27,34,42 indeed, we found that watching television for 3 hours was associated with increased who bmi percentiles levels, in agreement with other south african studies undertaken on local samples of children. 7,21,27 further, in the current study, the majority of black girls reported expending more energy by walking to and from school than those of mixed ancestry and white girls. similarly, the reliance on motorised vehicles for transport has been associated with a decline in physical activity, linked to weight gain. 3,12,15,39,53 paq also showed comparable construct validity for inactivity when compared with inactivity generated by the television programme list. however, the total time spent by the girls watching television each day generated by the paq, was more than three times that generated using the television programme list. the use of the television programme list might have underestimated inactivity as it may have overlooked other programmes watched in conjunction with adults. moreover, due to programmes constantly changing, some of the programmes in the list were no longer featured on television. conversely, systemic error (or bias) may have resulted in an over-estimation of minutes spent watching television per day when television watching was recalled over the past week using the paq. indeed, ridley (2005) table v. girls’ physical inactivity according to ethnicity measured by the physical activity questionnaire (paq) and the television programme list levels of inactivity black mixed ancestry white paq television time (min/day) weekday 80(0;120)* 100(15;180) 120(25;200)* weekend 160(0;260)* 180(35;300) † 240(30;350)* † total 240(0;380)* 210(30;420)* ** 270(30;450)** paq technology-based entertainment (sum of television and computer time, min/day) total 240(180;480)* 480(300;600)* ** 300(180;540)** television programme list (television time, min/day) total 36(18;81)* ** 75(78;105)*‡ 78(51;129)** ‡ values are in median (±interquartile range). matching superscript symbols represent groups that are different to each other, *, † = p<0.05 and **, ‡ = p<0.001. < 3hrs >/=3hrs 0 25 50 75 < 3hrs >/=3hrs te le v ision v ie wing time w h o b m ip e rc en ti le (m ea n )  fig. 1. the who bmi percentiles of the girls who reported watching less than 3 hours of television compared with those who reported watching 3 or more hours of television each day. mean who bmi percentile of girls who reported watching > 3 hours of television was higher than those girls who watched <3 hours of television each day (p<0.05). pg117-124.indd 121 1/11/08 12:24:31 pm 122 sajsm vol 19 no. 5 2007 demonstrated that asking ‘how many minutes of television did you watch the previous week?, 35 resulted in an overestimation of the total time of inactivity compared with when television watching was capped within a 24-hour time frame. ridley suggested that such an error can be reduced by rephrasing the question and making it simpler. indeed, the television programme list was simpler and possibly made recalling easier. nonetheless, both the paq and the television programme list managed to identify significant ethnic differences in inactivity, such that black girls spent less time watching television than girls of mixed ancestry and white girls. these ethnic differences remained significant, even after adjusting for housing density and asset index, which were also significant correlates of television watching time. in contrast, mcveigh et al. found that white children were more active and watched less television than black children. 27 however, in their study they found no differences in socioeconomic status between ethnic groups, whereas the black participants in the current study presented with lower socioeconomic status compared with mixed ancestry and white girls, which may explain the differences between studies. further, the paq showed comparable construct validity for moderate and vigorous activities compared with the activitygram. however, the total activitygram energy expenditure was almost double that of the paq. a possible explanation for these differences can be the underestimation of energy expenditure by paq brought about by memory decay when asking the children to recall their activities over the past 12 months, which may lead to systemic error or bias in reporting. there is evidence to suggest that children might have difficulty in recalling activities that they participated in within the time frame of 12 months. 35,36 thus rephrasing and simplifying the questionnaire to ask the children about the minutes they spent in activity on the previous day, on a number of occasions, is generally recommended. in contrast, the activitygram asked the girls to recall their activities the previous day from the time they woke up in the morning, until the time they went to bed (from 7am to 10:30 pm). 48 despite differences in absolute energy expenditure, we found a weak but significant positive relationship between the two measures, which is in agreement with other similar international studies. 37,38,46,50,51 these studies argue that when using complex and lengthy questionnaires children become bored, which may negatively impact the instrument’s validity, yielding weak spearman’s ρ. this validation study was undertaken as part of a larger project, during which the girls were also asked questions on their diet and physical activity knowledge, attitudes, beliefs and health behaviours. this may have contributed to the respondent burden, thereby increasing fatigue and boredom during the interviews, which may have impacted on the quality of the relationships we obtained. in this study we further observed significant ethnic differences in paq energy expenditure and a trend for ethnic differences in energy expenditure using the activitygram. black girls had the highest energy expenditure, followed by white girls and lastly the girls of mixed ancestry. higher levels of activity in the black girls could possibly be attributed to their lower socioeconomic status, measured by the asset index and household density. indeed, monyeki and associates found that where space is limited and there is overcrowding, children will spend more of their time playing unstructured and informal activities away from home. 29 participation in play sport has previously been associated with increased energy expenditure. 39,53 finally, this study showed reasonable test-retest reliability of the paq only for structured school sports. this can be explained by the fact that girls of this age (9 12 years) can recall and report participation in structured school sports well, compared with other unstructured game sports played at home and at school or in sports clubs. these unstructured activities may vary from time to time due to the school term (such as writing exams, weather or seasonal changes). 4,23,31,47 furthermore, memory decay has been reported in other international studies in children, where it was found that children under the age of 10 could with reasonable accuracy recall the activity from the previous day, but had great difficulty with days further back in time. 4,6,47 the majority (69%) of our participants were 10 years and younger, a factor that would therefore influence the reliability of the activity recall after 7 days. conclusion despite the relatively weak associations between the paqderived energy expenditure and inactivity, against those derived from the activitygram-derived energy expenditure and television-derived time spent in sedentary behaviour, we found that the paq may be useful in characterising the physical activity levels and patterns of the south african children of varying socioeconomic background. the paq shows a potential in highlighting health benefits associated with adoption of physical activity, such as reduced body fatness and bmi levels. further, its usefulness in quantifying energy expenditure has been highlighted, such that it is able to distinguish between the intensity levels of the activity, by identifying moderate and vigorous energy expenditure in south african schoolgirls. it also enables us to quantify and distinguish energy expenditure generated by activities performed at school, out of school, formal and informal, with the more formal activities showing good reliability. further, it quantifies time spent in sedentary behaviours such as watching television, using computers, relying on motorised vehicle for transport, and identifies whether physical education is included in the school curriculum and if children are participating. indeed, the strength of association is comparable with those observed in similar studies where validation of self-administered questionnaires was tested in children. 18,35,37,51 studies suggest that validity may be improved by making questionnaires simpler and only asking about children’s activity over a 24-hour period. pg117-124.indd 122 1/11/08 12:24:32 pm sajsm vol 19 no. 5 2007 123 another approach is for researchers to make use of objective physical activity measures instead of questionnaires. further evidence suggests that choosing a suitable measure of physical activity/inactivity for children is often a trade-off between accuracy, depth of information gathered, cost and subject and researcher burden. information provided by such questionnaires is relevant for south africa, where inactivity and the prevalence of obesity in children are becoming an important public health issue. however, additional studies are required using objective measures of physical activity, such a pedometry or accelerometry, to better understand the utility of the paq for children. acknowledgements this study was funded by the nestlé foundation, the medical research council of south africa, the university of cape town, the south african department of science and technology and the national research foundation (scholarship for z mciza). gratitude is extended to all the principals, parents and learners in the cape town metropole primary schools in which the study 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110: e463-70. pg117-124.indd 124 1/11/08 12:24:40 pm hiv risk sajsm-sc1-f sajsm vol 17 no. 1 2005 11 introduction a survey conducted by the south african sports commission in 200241 showed the number of participants in all sports to be 14.7 million. this translates to approximately 10 million adults participating in sport. many adults participate in more than 1 sport. the average estimate is 1.5 sports per person. the sporting fraternity has to take cognizance of aids and its transmission and impact on sport because the probability of encountering an aids-infected person during sport is high. about 375 670 south africans were expected to die from hiv/aids in 2003, an increase of more than 30% of the estimated 219 660 aids-related deaths in 2000, according to projections by the human sciences research council.31 the attitude of health care professionals has added to the confusion regarding the spread of the hiv virus. these professionals wear gloves while treating patients, yet maintain at the same time that the risk of transmission is very low.10 in america a large number of leading sports personalities have made their hiv status public. these popular sports heroes have contributed towards demystifying the disease and have created greater public awareness by educating the public on the disease. this has not occurred in south africa. those most affected by hiv transmission are 18 25 year old. this age group has the highest number of individuals participating in sports.11,22,29 these young adults play a central role in social, economic and political activities. any epidemic that threatens to deplete this cohort, undermines the social, economic and demographic stability of society.19 the hiv/aids barometer on estimated hiv infections worldwide stood at 58 580 614 at 05h00 on wednesday 11 august 2004.32 the sports environment is a social, recreational, economic and competitive arena providing opportunities for interaction and a venue for transmission. competitive athletes are usually drawn from an economically active sector of the population.5 these athletes form part of an elite group which one would presume to be knowledgeable about hiv/aids. therefore the focus of this study was to ascertain the attitudes of sportspersons involved in contact and non-contact sports, towards hiv-positive individuals in a competitive sport environment and the risk of hiv transmission through sport. calabrese10 concluded that the hiv transmission risk in a sporting environment is very low. brown et al.8 calculated the risk of hiv transmission through sport to be less than 1 infection per 85 647 821 game contacts. the centers for disease control and prevention13 placed the odds of contracting hiv during a sporting event to be greater than a million to 1. original research article attitudes towards the risk of hiv transmission in sport s reddy (m sport science) y coopoo (d phil, facsm) department of sport science, university of kwazulu-natal, durban correspondence: y coopoo university of kwazulu-natal private bag x54001 durban 4000 tel: 031 260 7394 fax: 031 260 7903 e-mail: coopooy@ukzn.ac.za abstract objective. there is a real risk of transmitting hiv through open wounds during participation in sport. the aim of this study was to investigate athlete s knowledge and attitudes towards hiv transmission in a competitive sport environment how their sporting codes, demographics, knowledge and interaction with colleagues influenced their attitudes. design. a questionnaire was administered to elite athletes (n = 575) competing in 11 sport codes including high, medium and low-risk sports, and undergraduate students (n = 46) from a sport science department. athletes from all economic backgrounds, who competed at national, provincial or at first-division level, were included in this study. the questionnaire was distributed during national tournaments and training sessions. results. sixty-three per cent of athletes believed that a risk of hiv transmission exists in sport participation. fiftyeight per cent believed that they had a right to know if a teammate/opponent was hiv-positive, and 62% believed that all athletes should be tested for hiv. fifty per cent of the respondents indicated that they would participate against individuals who were hiv-positive. most athletes (88%) believed that more education on hiv transmission in sport was needed and 58% felt that hiv should be a notifiable disease in sport. forty-six per cent of the athletes indicated that they would participate in competition even though they were hiv-positive. conclusion. the threat of infection or transmission did not deter athletes who were afflicted or unafflicted with hiv from participating in competitive sports. hiv risk sajsm-sc1-f 5/3/05 8:52 am page 11 12 sajsm vol 17 no. 1 2005 no studies have documented athlete-to-athlete transmission from blood exposure on the playing field, except for 1 anecdotal report of an italian soccer player.16,48 in this incident both players clashed, sustaining open, bleeding wounds resulting in possible mixing of blood. this was the first documented case, published in 1990, of hiv transmission that occurred directly as a result of sports participation. at present, accurate data on hiv transmission during sports participation is only available for american football players and professional boxers in south africa. in american football the risk of hiv transmission has been calculated to occur at a rate of approximately 1 player per 100 000 000 games. in a boxing match of 12 rounds, the risk of an open bleeding wound has recently been calculated at 47%. in a study42 of 952 boxers in south africa hiv disease was determined at 9% and the risk of contact between boxers during a fight at 100%. the risk of infection among professional south african boxers has been calculated at 1 infection in 4 760 fights.42 according to gatheram19 there is a need for an inter-sectoral response to hiv/aids. it is fundamental that hiv is not seen as merely a health issue, for it is indeed much more than that. it is a welfare issue, a legal issue, an educational issue, a human rights issue, and a sports issue. for these reasons alone it is of paramount importance that the role of sport and hiv/aids be utilised to unite our diverse country around this human issue.19 methods the study design was that of a questionnaire survey consisting of 22 questions. the questionnaire was designed to assess variables that influence athletes attitudes towards the risk of hiv transmission of through sport. the research questionnaire was influenced by a similar study conducted by calabrese10 in 1993, which was confined only to college students and did not differentiate between risk categories. in the present study the questionnaire was amended to include variables that might have an influence on the formation of attitude to hiv. these variables included demographics, knowledge and fear of transmission, knowledge or lack of knowledge on the benefits of exercise in hiv-infected individuals, and the influence of health care workers, sports personnel and the media in hiv/aids education. questions were divided into 4 major categories namely: (i) demographic data that could influence attitude formation; (ii) analysing responses to gauge attitude, knowledge and fears about hiv transmission in sport; (iii) assessing athletes knowledge of the benefits of exercise in hiv-infected individuals; and (iv) the influence of health care workers, sports personnel and the media in promoting education and awareness of hiv/aids in sport questionnaires were administered to 22 sports clubs, comprising 11 sport codes. participants were categorised into the following risk categories: (i) high-risk (173 respondents) comprising boxing (n = 14), karate (n = 44), wrestling (n = 52), and rugby (n = 63); (ii) medium-risk (201 respondents) comprising field hockey (n = 45), basketball (n = 46), volleyball (n = 50), and soccer (n = 60); and (iii) low-risk (201 respondents) comprising tennis (n = 34), athletics (n = 60), and swimming (n = 61). sport science students (n = 46) were included in the lowrisk category as this was a mixed group of athletes participating at a high level of sport. during the period between january 2001 and august 2001, 900 questionnaires were handed out to athletes competing at provincial or national level, or in a first-division club. these athletes were selected randomly. five hundred and seventy-five questionnaires were completed. this resulted in a response rate of 64%. the gender balance for returned questionnaires was 378 males to 193 females, with 4 respondents not disclosing their gender. the researchers administered most of the questionnaires. the balance were administered by colleagues from the sport science department, and administrators of various sports institutions and clubs. the majority of the questions required that the athletes place a tick in the relevant block. there were 11 yes or no questions. open-ended questions formed part of the questionnaire, countering the restrictive nature of responses confined only to the alternatives provided. the researchers and a team of colleagues visited approximately 22 clubs during administration of the questionnaires. further data were collected at tertiary institutions and selected competitive tournaments and matches. the instructions for answering the questionnaire were clear. the athletes co-operation was sought in this study; it was explained that participation was completely voluntary and that all responses would be kept strictly confidential. athletes signed informed consent to participate in the study. ethical clearance was obtained from the university of kwazulu-natal (westville campus). no names were written on the questionnaires, thus maintaining the anonymity of the responses. analysis the completed questionnaires were entered into a database, checked for inconsistencies, and spoilt forms were removed from the analysis. statistics were compiled by the department of statistics at the university of kwa-zulu-natal. the spss version 9, library of statistical packages was used to compute the descriptive statistics reported in this study (microsoft spss (version 9) standard version, windows 2001). since there is no comparative study of this nature in south africa, no inferential statistics comparing results with different provinces could be analysed. results the results reported refer to the attitudes of athletes towards the risk of hiv transmission in a sporting environment. the study assumed that the athletes answered the questions truthfully and sincerely. however this is an inherent limitation of questionnaire studies. table i shows the demographic data of the sample. sixty-six per cent of athletes in the study were male, and hiv risk sajsm-sc1-f 5/3/05 8:52 am page 12 sajsm vol 17 no. 1 2005 13 33% female respectively (table i). a study by the south african sports commission41 concluded that more males participated in sport than females, at 46% versus 27%. the majority of athletes (46%) surveyed in this sample fell into the 19 25-year age group. this is also the most sexually active group, therefore most at risk of hiv infection.1,42 research in the usa has repeatedly found that approximately 21% of aids cases involve people aged 20 29 years.24 a higher percentage of respondents were in the over-31 age group (18%) than in the 26 31 age group (12%). more than half (52%) of the respondents indicated that they had a tertiary level of education. generally this is the age group (18 25 years) from which most elite athletes are drawn, and many of them are students.29 forty-one per cent of respondents were in the high-income group, which correlates with data obtained on educational background. general knowledge of hiv transmission was assessed in table ii. the majority of the athletes surveyed (64%) indicated that touching infected blood posed a risk of transmission. a transmission risk exists only if the skin is broken and infected blood enters through this route.17,44 ninety-two per cent of respondents indicated that sharing needles was a means of transmission, especially among wrestlers and bodybuilders, who share needles used to inject steroids. two cases have been reported among bodybuilders.21,40 table iii investigated athletes knowledge of whether hiv could/could not be transmitted through sport participation. a large number (n = 355, 62%) of the athletes stated that hiv could be transmitted through sport participation. twentyfive per cent of respondents in the high-risk category, 18% in the medium and 19% in the low-risk category believed that sport involves a risk of hiv transmission. there was a significant difference (p < 0.05l) in attitudes among the various sport codes and risk categories with regard to hiv being transmitted through sport participation. various questions were posed to athletes to determine their knowledge of hiv transmission through sport (table iv). in assessing attitudes towards hiv-positive athletes being allowed to participate in sport (question 1, table iv), the following was established. an equal percentage (14%) in the highrisk category responded both positively and negatively towards hiv-positive athletes being allowed to participate in sport. a larger proportion (30%) in the low-risk category and 27% in the medium-risk category were willing to participate with hiv-positive individuals. a total of 71% indicated that hiv-positive athletes should be allowed to participate, as opposed to 25%. fear of contracting the hiv virus (question 2, table iv) was indicated by 59% of the respondents, while 37% indicated that they were not afraid. the largest percentage of respondents (24%), who indicated such fear were in the high-risk category, as these sports posed the most risk of infection.18 this correlates with a large number of bleeding injuries encountered in high-risk sports. in the low-risk category, 15% indicated that they were afraid of contracting the hiv virus. table i. demographic information on respondents (n = 575) parameter number % gender male 378 66 female 193 33 no response 4 1 age (yrs) under 18 131 23 19 25 266 46 26 31 69 12 over 31 102 18 no response 7 1 education none 20 4 primary 13 2 high 233 40 tertiary 300 52 no response 9 2 income (r/month) below r1 200 185 32 r1 200 r2 000 51 9 above r2 000 237 41 no response 102 18 table ii. general knowledge of hiv transmission (n= 575) yes no response response methods of transmission n % n % sexual intercourse 557 97 18 3 sharing needles 528 92 47 8 blood transfusion 512 89 63 11 mother to child 455 79 120 21 touching infected blood 365 64 210 37 sharing eating utensils 15 3 560 97 shaking hands 10 2 565 98 hugging a person 6 1 569 99 table iii. knowledge of hiv transmission through sport, compared by risk category hiv transmission through sport risk category yes no unsure no response total high number 142 25 4 171 total% 25 4 1 30 medium number 105 92 1 198 total% 18 16 0 34 low number 108 91 199 total% 19 16 35 total number 355 208 5 7 575 total% 62 36 1 1 100 * all significant (p < 0.05) at the 5% level among the different risk categories. hiv risk sajsm-sc1-f 5/3/05 8:52 am page 13 14 sajsm vol 17 no. 1 2005 t a b l e i v. k n o w le d g e b a s e o f a th le te s r e g a rd in g h iv t ra n s m is s io n t h ro u g h s p o rt ( n = 5 7 5 ) 1 . d o y o u t h in k h iv -p o si tiv e a th le te s sh o u ld b e a llo w e d t o p a rt ic ip a te i n s p o rt ? 2 . d o y o u o r yo u r te a m m a te s w o rr y a b o u t co n tr a ct in g t h e h iv v ir u s th ro u g h s p o rt ? 3 . w o u ld y o u b e w ill in g t o p a rt ic ip a te i n s p o rt w ith a th le te s w h o a re k n o w n t o t e st p o si tiv e fo r h iv ? 4 . w o u ld y o u c o n tin u e t o p a rt ic ip a te i n s p o rt i f yo u w e re h iv -p o si tiv e ? 5 . d o y o u t h in k a ll a th le te s sh o u ld b e s cr e e n e d fo r h iv ? 6 . d o y o u t h in k h iv s h o u ld b e a n o tif ia b le d is e a se i n c o m p e tit iv e s p o rt ? 7 . w o u ld k n o w in g y o u r o p p o n e n t w a s h iv -p o si tiv e c h a n g e y o u r st ra te g y to w a rd s th e s p o rt ? 8 . d id y o u r co a ch /d o ct o r sp e a k to y o u a b o u t th e r is k o f h iv t ra n sm is si o n t h ro u g h s p o rt ? 9 . w h e n m e d ic a l p ro fe ss io n a ls ( e .g . d o ct o rs , p h ys io th e ra p is ts e tc ) tr e a t b le e d in g i n ju ri e s, d o t h e y u se g lo ve s? 1 0 . d o y o u f e e l th a t th e re s h o u ld b e m o re e d u ca tio n o n h iv t ra n sm is si o n t h ro u g h s p o rt ? n u m b e r to ta l % n u m b e r to ta l % n u m b e r to ta l % n u m b e r to ta l % n u m b e r to ta l % n u m b e r to ta l % n u m b e r to ta l % n u m b e r to ta l % n u m b e r to ta l % n u m b e r to ta l % 1 7 3 1 9 3 1 4 2 1 8 3 1 6 3 1 9 3 2 2 4 6 1 1 0 2 1 5 3 8 1 1 4 1 3 5 2 4 4 3 7 7 1 1 2 1 3 0 2 3 1 3 3 2 3 1 2 6 2 2 7 6 1 4 1 5 8 2 7 1 6 2 2 8 1 5 3 2 7 11 8 2 0 1 0 7 1 9 1 3 8 2 4 11 2 2 0 1 0 4 1 8 8 0 1 4 5 9 1 0 1 7 0 3 0 1 6 3 2 8 1 7 5 3 0 8 6 1 5 11 4 2 0 1 7 2 3 0 11 2 2 0 9 5 1 7 9 3 1 6 4 6 8 1 8 9 3 3 1 7 8 3 1 4 0 9 7 1 3 3 9 5 9 2 6 4 4 6 3 8 1 6 6 3 5 4 6 2 3 3 2 5 8 2 9 9 5 2 1 8 1 3 2 5 1 7 9 0 5 0 3 8 7 8 1 1 4 3 5 6 6 8 1 2 9 6 1 7 3 8 7 3 5 6 4 5 8 9 4 1 6 8 1 6 1 4 1 7 7 3 1 3 1 9 3 4 9 9 8 4 1 4 9 1 1 6 11 4 2 0 1 4 0 2 4 2 8 5 3 1 5 2 0 4 1 0 5 1 8 1 7 3 2 5 4 8 0 1 4 9 7 1 7 9 4 1 6 1 5 3 2 7 9 2 2 0 4 1 4 2 2 5 2 1 3 3 7 1 0 4 1 8 1 7 0 3 0 2 0 2 3 5 2 2 3 3 9 2 5 3 4 4 3 8 7 6 7 4 5 8 5 7 1 0 6 1 .0 1 0 .2 6 0 1 0 2 0 .3 3 0 .5 1 0 .2 6 7 1 2 4 0 .7 2 0 .3 1 0 .2 1 0 .2 2 0 .3 6 6 1 2 1 0 .2 1 0 .2 1 0 .2 7 1 .2 4 0 .7 1 9 3 3 4 6 1 3 0 .5 1 0 .2 1 0 .2 1 0 .2 3 0 .5 y e s r is k c a te g o ry to ta l h m l n o r is k c a te g o ry to ta l h m l n o t s u re r is k c a te g o ry to ta l h m l n o re s p o n s e hiv risk sajsm-sc1-f 5/3/05 8:52 am page 14 sajsm vol 17 no. 1 2005 15 the response to participating with hiv-positive athletes was as follows (question 3, table iv). in the high-risk category, 12% of the respondents did not want to participate with athletes known to be hiv-positive, whereas in the low-risk category 20% and in the medium-risk category 19% of the respondents agreed to participate against hiv-positive individuals. a majority of the respondents (46%) were willing to participate with hiv-positive, while 18% were unwilling, 34% were not sure how they felt and 2% did not respond at all. most athletes (66%) indicated that they would continue to participate in sport if diagnosed hiv-positive, against 30% who indicated that they would not participate (question 4, table iv). this correlates with a knowledge of the benefits of exercise for hiv-positive individuals. more respondents in the medium (24%) and low-risk (30%) categories indicated that they would continue to participate in sport compared with those in the highrisk category (12%). sixty-two per cent of respondents indicated that all athletes should be screened for hiv compared with 35% who indicated that athletes should not be screened (question 5, table iv). fifty-eight per cent of the sample saw a need for testing in order to make hiv a notifiable disease in sport (question 6, table iv). the majority (23%) of the yes responses came from the high-risk category. this correlates with the high incidence of bleeding injuries in high-risk sport and the greatest fear of contracting the hiv virus.34 the majority of respondents (52%) indicated that knowing their opponent was hiv-positive would influence their game strategy, while 44% indicated that it would not influence their game strategy (question 7, table iv). only 32% of the respondents indicated that they were informed of the risk of hiv transmission through sport by doctors and coaches, while 67% indicated that they were not (question 8, table iv). respondents were asked whether medical professionals used gloves when treating bleeding injuries; 90% indicated that they did, while only 8% indicated that they did not (question 9, table iv). a large majority of respondents (87%) indicated that more education on hiv transmission through sport was essential (question 10, table iv). sources of information on the promotion of hiv awareness show that television (84%) was the most effective medium (table v). the least effective were managers and coaches. this again indicates the need for sport and health professionals to become more proactive on the hiv/aids issue. respondents displayed a good knowledge of the benefits of exercise for the hiv-positive individual, except with regard to maintaining weight and assistance in sleeping. a majority of the respondents (81%) were aware of the psychological benefit of exercise in terms of making a person feel good (table vi). discussion a number of athletes left questions unanswered. the reasons for this could be that some of the questions might have been too sensitive or intrusive. a total of 900 questionnaires were handed out to athletes. only 575 questionnaires were completed. table i shows that the majority of the athletes were male. these findings are similar to those of a study by the south african sports commission, which concluded that more males participated in sport than females (46% versus 27%).41 the larger number of athletes in the over-31 age group could be attributed to older athletes who participate in athletics (long distance). road running is currently increasing at a rate of 7% per annum.41 although there has been speculation on the possible transmission of hiv through saliva and sweat, it has been proved that such transmission is not possible.9,26,51 even though sweat is the most common body fluid exchanged between athletes, it is not considered a risk factor for hiv transmission among athletes. mcgrew et al.34 stated that hiv transmission risk exists if the skin is broken and infected blood enters through this route. table ii indicates that this sample of athletes were knowledgeable about hiv transmission methods generally. theoretically a risk exists, but most experts agree that the risk of infection during competition is extremely low, and that the principal risks faced by athletes are related to off-the-field table v. access to information on hiv (n = 575) sources of information yes response no response on hiv/aids n % n % doctors 296 51 279 49 physiotherapists 62 11 513 89 books 388 67 187 33 internet 225 39 350 61 coaches 116 20 459 80 managers 62 11 513 89 newspapers 431 75 144 25 magazines 418 73 157 27 radio 406 71 169 29 television 484 84 91 16 school 304 53 271 47 word of mouth 382 66 193 34 table vi. knowledge of the benefits of exercise for hiv-positive individuals benefits yes no usure no response n % n % n % n % improves health 444 77 74 13 1 2 56 10 improves fitness 453 78 68 12 1 2 53 9 improves muscular strength 448 78 69 12 1 2 57 10 helps to control/ maintain weight 385 67 101 18 1 2 88 15 makes you feel good 464 81 58 10 1 2 52 9 sleep better 386 67 100 17 1 2 88 15 improves quality of life 449 78 72 13 1 2 53 9 hiv risk sajsm-sc1-f 5/3/05 8:52 am page 15 16 sajsm vol 17 no. 1 2005 activities.9,10,14,23,50 no studies have been documented on athlete-to-athlete transmission from blood exposure on the playing field, except for 1 anecdotal report of an italian soccer player.48 however, the document rendered insufficient evidence to call the incident a conclusive case.10 respondents in all 3 risk categories felt that hiv may be transmitted through sport participation. the data reveals that although the sportspersons were knowledgeable about the transmission modes of hiv, they still feared playing with or against infected players. this fear seems unjustified as their knowledge on modes of transmission was excellent. there were a few concerns by sportspersons pertaining to other situations that could involve risk of transmission. these situations were blood from the eyes or mouth especially in contact sport, possible cross-infection from first aiders, openwound contact, and playing contact sport. most athletes (85%) knew that contact sport posed more of a transmission risk than non-contact sport. sports considered to involve the most potential risk are boxing, wrestling and the martial arts18 because of close contact and risk of blood exposure from broken skin and/or membranes. other semi-contact sports such as basketball and soccer provide opportunities for open bleeding wounds to occur, providing a theoretical possibility of hiv transmission.40,49 the media exposure given to boxers and the compulsory hiv testing required could have convinced athletes that contact sport poses the greatest threat of hiv transmission. the south african boxing commission, like others worldwide, does not publish statistics on the number of hiv-infected boxers because of a serious controversy in 1995 after such disclosure.30 inquiry into the number of bleeding injuries sustained in the total sample during competition revealed that 37% encountered no bleeding injuries. one incident of a bleeding injury per match was reported by 30% of the sample. the highest number of bleeding injuries was reported in rugby in the high-risk category (5 or more bleeding injuries in a match). the high incidence of bleeding in contact sport necessitates that all sport personnel be educated on how to treat and control bleeding so that it does not pose a transmission risk.3,24 only 1 case of hepatitis b transmission has occurred in sport, when 5 of 10 young japanese sumo wrestlers were infected from a teammate who bled on them during matches.26 researchers, sport and medical organisations have developed policies regarding hiv transmission in the sports world emphasising the need for universal precautions.4,14,23,25,40,45 sports that showed most acceptances were in the individual and low-risk category. this finding is alarming due to the low incidence of bleeding injuries encountered in these sports. low-risk individual sports like tennis afford few opportunities for physical contact. however, athletes displayed a fear of hiv transmission, which is not justified given the nature of the sport. one can only surmise that sensationalised reports of escalating infection rates have greatly contributed to fear of infection. jackson25 sought to construct a framework for ethical deliberation concerning hiv and sport to combat the isolation experienced by hiv-infected individuals participating in sport. athletes in the calabrese10 study questioned why it was acceptable to require testing for drugs but not for hiv. it seemed to them that society cares more about a player s drug status than his/her hiv status. hiv is the only infectious disease for which anonymous testing is publicly funded, an exception that has been controversial.6 in south africa it is mandatory for all boxers to undergo an annual hiv-antibody test, to complete a medical examination, and to receive medical clearance before being allowed into the arena. the general exception to this is when boxers travel to the usa or to britain where they must present results from tests conducted within the last 3 months.47 matseka36 stated that about 9% of south african boxers have tested positive for hiv and are therefore banned from boxing. matseka36 calculated that with the 9% incidence, boxers would have to fight 50 000 bouts before transmitting the virus. the american academy of pediatrics committee on sports medicine and fitness,2 the world health organization consensus statement consultation on aids and sports,50,51 the canadian academy of sports medicine task force on infectious diseases in sports12 and the national collegiate athletic association37 have all concluded that the risk of infection from one athlete to another (even in contact sports such as football, boxing and wrestling) is not sufficient to warrant a policy of mandatory testing. since the risk of hiv transmission in sport is not zero, many voices have advocated mandatory testing. however, several problems are associated with mandatory hiv testing. these include the high probability of false-negative and false-positive test results as well as issues regarding the right to privacy.39 education remains the key in the effort to prevent bloodborne pathogen transmission. sports medicine personnel play an important role in educating athletes, their families, athletic trainers, health care providers, coaches, and officials involved in sport.39 during 2002/2003 awareness was advanced mainly through the khomanani campaign and the lifeskills and hiv/ aids education programme in schools.43 most research studies recommend that hiv-positive individuals exercise as most participants show improvements after commencing on an exercise programme.7,27,28,30,33,35 the study by rigsby et al.39 on hiv-positive individuals in stages ii, iii and iv, indicated that bicycle exercise training for 12 weeks significantly increased neuromuscular strength and cardiorespiratory fitness. pedersen38 and dudgeon et al.15 maintain that the amount of data available does not allow any strong conclusion to be drawn regarding possible beneficial or detrimental effects of training, regardless of intensity and duration, on the immune system of hiv-positive subjects. this uncertainty is caused by conflicting results found among studies. the studies by stringer46,47 on hiv and aerobic exercise revealed that 6 12 weeks of moderate exercise sessions (3 times per week for 1 hour), significantly improved aerobic capacity. other benefits included improved functional status, improved immune function indices, maintenance of/improvements in lean body hiv risk sajsm-sc1-f 5/3/05 8:52 am page 16 sajsm vol 17 no. 1 2005 17 mass/weight, improved mood (reduced depressive symptoms) and improvement in the quality of the patient s life. recent studies by dudgeon et al.15 concluded that the use of both aerobic and resistance exercise improves physiological parameters such as strength, endurance, time to fatigue and body composition in the hiv-infected population. exercise has also been used successfully to treat psychological conditions such as depression and anxiety that are common in hiv-infected individuals.20 thus, advice to hiv-positive patients to perform physical exercise relies on the positive effects of muscle strengthening and oxygen uptake and the psychological relief achieved in those patients able to participate in a training programme. conclusions in the present study 46% of respondents indicated that they would play against hiv-positive sportspersons, 18% indicated that they would not, and 34% of respondents were unsure of their views. most athletes (85%) knew that contact sport was more of a risk for transmission than non-contact sport. fifty-eight per cent of respondents believed that aids should be a notifiable disease in sport. a fear of contracting aids during sport was indicated by 59%, while 37% were not afraid of transmission during sport. the largest percentage (24%) of the respondents who indicated their fear of transmission through sport came from the high-risk category. eighty-seven per cent of these sportspersons wanted more information on aids. coaches and doctors contributed the least towards education on the risk of hiv transmission in sport. the athletes felt strongly that coaches and doctors should go through hiv training programmes so that they can provide informed knowledge to the athletes under their supervision. most respondents believed that exercise should form an integral part of hiv/aids patients lives as it improves quality of life. recommendations all athletes should complete an hiv education programme and be informed about the possibility of transmission. physicians, coaches and managers should counsel hivinfected patients, especially those in boxing, as they are tested twice a year. coaches and managers should complete a compulsory hiv training programme before being appointed to these positions. references 1. allen dm, simelela n, makubulo l. epidemology of aids in south africa. south african journal of hiv medicine 2000; july: 9-15. 2. american academy of pedriatrics committee on sports medicine and fitness. human immunodeficiency virus in the athletic setting. pedriatrics 1991; 88: 640-1. 3. active australia australian sports development group. blood rules, ok kit. australia: australian institute of primary care, 2003. 4. australian national council on aids and australian sports ‘medicine federation. hiv positive people and sport. canberra: australian national council on aids, 1994. 5. bendix s. industrial relations in south africa. cape town: juta and company, 1992. 6. bindman ab, osmond d, heecht fm, et al. multistate evaluation of anonymous hiv testing and access to medical care. jama 1998; 280: 1416-21. 7. birk tj, macarthur rd. chronic exercise training maintains previously attained cardiopulmonary fitness in patients seropositive for human immunodeficiency virus type 1. sports medicine training and rehabilitation 1994; 5: 1-6. 8. brown ls, phillips ry, brown cl, knowlan c, castle l mover j. hiv/aids policies and sports: the national football league. med sci sports exerc 1994; 26:403-7. 9. calabrese lh, kelly d. aids and athletics. physician and sportsmedicine 1989; 17: 127-32. 10. calabrese lh. hiv and sport. what is the risk? physician and sportsmedicine 1993; 21: 172-80. 11. campbell c, williams b, gilgen d. is social capital a useful conceptual tool for exploring community level influences on hiv infection? aids care 2002; 14: 41-54. 12. canadian academy of sports medicine task force on infectious disease in sports. hiv as it relates to sport. clin j sport med 1993; 3:65-6. 13. centers for disease control and prevention. update: trends in aids incidence, deaths and prevalence. morb mortal wkly rep 1997; 46: 16573. 14. derman w. draft position statement: hiv/aids in sport. south africa sports medicine association and the department of health of south africa, july 1997. 15. dudgeon wd, phillips kd, bopp cm, hand ga. physiological and psychological effects of exercise interventions in hiv disease. aids patient care stds 2004; 18: 81-98. 16. eicher er. contagious infections in competitive sport. sports science exchange 1995; 8: 224-7. 17. friedland gh, klein rs. transmission of the human mmunodeficiency virus. n engl j med 1987; 317:1125-35. 18. garl t, hrisomalos t, rink l. transmission of infectious agents during athletic competition: a report to all national governing bodies of the us olympic committee sports medicine and science committee. colorado springs, 1991. 19. gatheram v. hiv/aids in kwazulu-natal. the daily news. 14 july 1999. 20. hengge ur. testosterone replacement for hypogonadism: clinical findings and best practices. aids reader 2003; 13: suppl 12, s15-21. 21. hamel r. aids: assessing the risk among athletes. physician and sportsmedicine 1992; 20: 139-46. 22. human sciences research council. human sciences research council on sport participation in south africa. pretoria: hsrc, 1982. 23. howe wb. preventing infectious diseases in sport. physician and sportsmedicine 2003; 31: 78-88. 24. hunt bp. hiv/aids knowledge and behaviour in a cohort of college student athletes. journal of international council for health, physical education, recreation, sport and dance 1994; 6: 121-8. 25. international federation of sports medicine. aids and sports. fims position statement. paris: 1-4. 26. kashiwagi s, hayashi j, ikematsu h. an outbreak of hepatitis in members of a high school sumo wrestling club. jama 1982; 248: 213-4. 27. kell r, jenkins a. hiv transmission and sport: realities and recommendations. strength and conditioning 1998; 2: 58-61. 28. laperriere a, flethcher mh, antoni mh, klimas ng, ironson g, schneiderman n. aerobic exercise training in an aids risk group. int j sports med 1991; suppl 2: s53-5. 29. lightbown r. aids our sporting scourge. south african sports illustrated 2001; feb: 89-93. 30. leach l. hiv/aids in sport. science in africa 2003 (http://www.scienceinafrica.com) 31. aids map: undermining sa s culture of violence (editorial). mail and guardian; february 2003: 7-13. 32. hiv/aids barometer (editorial). mail and guardian; august 2004: 9-10. 33. macarthur rd, levine sd, birk tj. supervised exercise training improves cardiopulmonary fitness in hiv-infected persons. med sci sports exerc 1993; 25: 684-8. 34. mcgrew c, randall w, schneidwind k, gikas p. survey of ncaa institutions concerning hiv/aids policies and universal precautions. med sci sports exerc 1993; 25: 917-21. 35. mars m. hiv infection and exercise. sports med 2000; 2: 3-10. hiv risk sajsm-sc1-f 5/3/05 8:52 am page 17 18 sajsm vol 17 no. 1 2005 36. matseka p. hiv and boxing. monday paper 1998; 17(21). cape town: department of communications, uct. 37. national collegiate athletic association. ncca sports medicine handbook 1992. aids and intercollegiate athletics. overland park: ncca, 1992. 38. pedersen bk. hiv, exercise, and immune function. in: sankaran g, volkwein ka, bonsall dr, eds. hiv/aids in sport. champaign, ill∴ human kinetics, 1999. 39. rigsby lw, dishman rr, jackson aw, maclean gs, ravan rb. effects of exercise training on men seropositive for the human immunodeficiency virus-1. med sci sports exer 1992; 24:6-12. 40. sankaran g, volkwein ka, bonsall dr. hiv/aids in sport: impact, issues, and challenges. champaign, ill∴ human kinetics publishers, 1999. 41. south african sports commission. bmi – sport info 2002. pretoria: sa sports commission, 2002: 8-11. 42. sanders f, gallaway m. hiv transmission during sport participation. johannesburg: wordsworth, 2002. 43. south african yearbook 2003/2004. cape town: macmillan: 385. 44. schwellnus mp. aids in sport: guidelines for prevention in sports participants. cape town: university of cape town / medical research council, 1997. 45. sheridan jw. blood-borne infections in sport. sport medicine news 1992; 10: 2-7. 46. stringer w. hiv and aerobic exercise. sports med 1999; 28: 389 95. 47. stringer w. mechanisms of exercise limitations in hiv individuals. med sci sports exerc 2000; 38: s412 21. 48. torre d, sampietro c, ferraro t. transmission of hiv-1 via sports injury. lancet 1990; 335: 1105. 49. whiteside a. the state of the aids epidemic at the beginning of 2001. aids analysis africa 2001; 11: 3-16. 50. world health organization (who) in collaboration with the international federation of sports medicine. consensus statement from consultation on aids and sports. geneva: who, 1989. 51. world health organization consensus statement. consultation on aids and sports. jama 1992; 267: 1312-4. hiv risk sajsm-sc1-f 5/3/05 8:52 am page 18 case report 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license the effect of systematic exercise training on skeletal muscle strength in a patient with advanced inclusion body myositis: a case study c d'alton,1 mbchb, msc; r johnstone,2 bsc(hons); c du plessis,2 bsc(hons); a pursad,2 bsc(hons); t a kohn,1,3 phd 1 hpals, division of physiological sciences, department of human biology, university of cape town, cape town, south africa 2 sports science institute of south africa, boundary road, newlands, cape town, 7725, south africa 3 department of medical bioscience, faculty of natural sciences, university of the western cape, bellville, south africa corresponding author: t a kohn (tkohn@uwc.ac.za) inclusion body myositis (ibm) is an acquired autoimmune myopathy with no known cause or cure. [1] clinically, the disease presents with a slow progressive decline in muscle strength, resulting from muscle fibre atrophy and the destruction of the quadriceps, forearm flexors and ankle dorsiflexion muscles as result of an inflammatory degenerative process within skeletal muscle, although the primary pathological process remains unclear.[1] histological sections of the muscle show inflammation of non-necrotic muscle fibres, with amyloid deposits (inclusions) evident within the vacuoles. ibm is initially difficult to diagnose as the first diagnosis presents as any inflammatory myopathy, with the inclusions only appearing much later.[1] there is currently no effective treatment for ibm. studies using endurance and resistance training have been shown to benefit the physical and psychological wellbeing of patients with ibm.[2-4] resistance training improves muscle strength through increased muscle fibre recruitment and hypertrophy and is therefore a viable and inexpensive method to aid and maintain muscle strength in ibm patients.[4] south africa currently has no standard exercise intervention programmes specifically designed towards improving muscle function in patients with myopathies, partly due to the conventional belief that exercise may cause more muscle damage. however, studies on ibm and other myopathies (e.g. mcardle disease) are proving that supervised exercise training is a viable adjunct in maintaining or improving muscle strength.[4,5] the aims of this study were to (i) evaluate the safety and (ii) the response of a 16-week supervised resistance training exercise protocol on the health and physical muscle performance of an elderly patient diagnosed with advanced stage ibm. the outcomes of this study may be applied more broadly to other myopathy cases. case report history the patient was a 71-year-old male in good health, despite having advanced stage ibm, of which clinical symptoms (muscle weakness) were already presented in november 2006. due to the clinical overlap between polymyositis and the earlier stage of ibm, the diagnosis of ibm was only confirmed on a muscle biopsy in october 2016. at the time of the exercise intervention (two years later), the patient was able to walk with the aid of a three-wheel walker but was unable to stand up from a chair by himself. during his functional assessment he was also found to have severe hyperextension of his knees. despite his physical limitations as a result of the ibm and the use of the following chronic medications, which included 100 mg/day allopurinol, 7.5 mg zopiclone and 25 mg amitriptyline at night, 0.4 mg/day tamsulosin, 5 mg/day folic acid, 300 mg/day irbesartan and 12.5 mg/day hydrochlorothizide, he was classified as healthy and cleared to take part in the exercise training intervention. methods the faculty of health sciences research ethics committee of the university of cape town (hrec 089/2018) approved the study and the participant provided his written informed consent. the protocol consisted of physical, clinical and fitness assessments, including the acquisition of blood samples. on inclusion body myositis (ibm) is an inflammatory and degenerative autoimmune disease that targets specific muscle groups, causing severe muscle weakness. exercise training is often contraindicated in myopathies as it may aggravate muscle damage and inflammation. although some reported positive outcomes in muscle strength of early diagnosed ibm patients undergoing resistance training, there remains uncertainty as to whether exercise could be beneficial and safe in advanced stage ibm. thus the aims of this research were to evaluate the safety and response of 16-weeks supervised resistance training on the health and muscle performance of an elderly participant diagnosed with advanced stage ibm. it was shown that the training had no adverse effects on the health of the patient. muscle strength measured at eight weeks and on completion of the intervention, remained the same as at baseline. in conclusion, the exercise programme was found to be safe and seemed to maintain muscle strength in a patient with advanced stage ibm. keywords: myopathy, autoimmune disease, muscle weakness, resistance training s afr j sports med 2022; 34:1-3. doi: 10.17159/2078-516x/2022/v34i1a13145 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13145 https://orcid.org/0000-0001-8791-7695 https://orcid.org/0000-0002-3871-3001 https://orcid.org/0000-0003-4152-6319 https://orcid.org/0000-0003-4624-8100 https://orcid.org/0000-0003-3048-3843 case report sajsm vol.34 no.1 2022 2 completion of the above tests, the participant underwent eight weeks of exercise training. the assessments were then repeated, followed by a second exercise training period of eight weeks, and a final assessment period on completion of the exercise intervention. clinical assessment prior to participation in the exercise sessions, the participant underwent a clinical review to determine his current physiological and psychological health status. this included the completion of the barthel index of activities for daily living questionnaire, the fatigue severity scale, as well as the visual analogue fatigue scale to evaluate fatigue severity, all of which were also repeated at week eight and 16. the clinical assessment entailed obtaining a complete medical history, including current medications, followed by a thorough routine clinical examination with specific emphasis on the cardiorespiratory, renal and neuromuscular systems. these were repeated midway through the programme. included in the assessment was a urine sample analysis using urinary dipsticks to exclude any baseline abnormalities, such as glucosuria, evidence of an uti or underlying renal disease, but most importantly, the presence of myoglobinuria (combur testing kit, roche). the rationale for this specific investigation was to assist in the monitoring for the presence of myoglobinuria as an additional method of monitoring for excessive muscle damage (rhabdomyolysis) during the exercise intervention phase if he was to present with delayed onset muscle soreness (doms) or dark-coloured urine which was not found throughout the intervention. the patient was deemed healthy and the exercise was not considered to pose any adverse risks to him. exercise test assessments isokinetic strength tests of the knee and elbow joints were conducted using a dynamometer (biodex medical systems, inc., ny, usa) before, during and after the exercise training programme (presented in table 1). handgrip strength was measured bilaterally using a hand-held dynamometer (camry electronic hand dynamometer eh101, camry scales, ca, usa). a blood sample for creatine kinase (ck) level determination was obtained a day after the exercise test to assess muscle damage both before the start of the intervention as well midway, because the exercise tests were considered to be the greatest risk for inducing muscle damage. the tests were not repeated after the final assessment due to the patient’s stable clinical nature. resistance training protocol exercise sessions (one hour each) were supervised by the same two qualified biokineticists, and consisted of moderateintensity resistance exercises (isometric and isotonic) using rubber bands, three times per week performed for 16 weeks. intensity was monitored using the rating of perceived exertion (rpe) scale (rate of 1 to 10) which was maintained between the scale of 7 and 8. whenever an exercise was too easy or difficult, adjustments to the programme were made. the patient was also closely monitored for any doms. discussion at baseline, ankle plantar flexion, wrist flexion and wrist extension were all within the normal range for the participant’s age category conforming to the muscles rarely affected by ibm.[1,6] interestingly, elbow extension appeared in the normal range and its strength was not affected by the disease. knee flexion and extension, ankle dorsiflexion and elbow flexion were severely compromised due to the ibm and well below the normal range. the muscles of the rightand leftsided limbs were found to be similarly affected by the disease, but grip strength was consistently greater in the left hand. however, this was considered to be weak when compared to the age-related ranges (table 1). the participant tolerated and complied well with the maximum exercise tests and training. he presented with no adverse side effects, besides the reporting of some stiff limbs due to the training. serum ck was measured (pathcare, cape town, south africa) a day after the initial and submaximum exercise tests (188 and 181 iu/l, respectively), concluding that muscle damage was minimal. overall, the data showed no significant change (improvement or deterioration) in the isokinetic strength of the participant, but variable responses between different muscle actions were noted for which the exact mechanisms are unclear. what is also unclear is whether table 1. maximum physical performance markers measured during the three assessments baseline assessment week 8 assessment week 16 assessment normal range for 70 83 age group isometric contractions (n·m) left right mean left right mean left right mean knee flexion 10 11 11 12 12 12 13 10 11 24 38 knee extension 11 10 11 9 13 11 9 12 11 55 71 ankle plantar flexion 41 42 42 31 30 31 43 22 33 25 46 ankle dorsiflexion could not initiate exercise could not initiate exercise could not initiate exercise 12 13 elbow flexion 6 7 6 4 7 6 1 8 5 14 19 elbow extension 15 18 17 15 22 18 16 25 21 14 23 wrist flexion 5 6 6 7 7 7 9 9 9 6 9 wrist extension 9 18 14 6 10 8 11 8 10 4 5 grip strength (kg) 27 6 16 17 6 11 21 8 15 28 42 isometric contractions values are presented as torque (newton·metres), whereas grip strength is reported in kilograms (kg). left indicates flexion or extension of the left limb; right indicates flexion or extension of the right limb. case report 3 sajsm vol. 34 no.1 2022 the exercise programme may have aided in the maintenance of muscle strength. a comparison of strength changes following a trial period without exercise would have been necessary to make such a conclusion. however, the participant’s self-reported scores for the fatigue severity scale and visual analogue fatigue scale tests improved from 31 to 28 and from 5 to 8, respectively, over the course of the exercise intervention, while his barthel score remained unchanged, suggesting a self-perceived reduction in his susceptibility to fatigue. the participant’s additional perceived benefits included better sleep patterns and mobility in bed, less achy muscle and joints, better distal perfusion, improved balance on standing, improved quadriceps, biceps and triceps strength, less over-extension of his left knee, and the ability to cover longer distances with his 3-wheel walker. he was still unable to rise unaided from a seated position or climb stairs, and he felt that his gluteal and hamstring muscles had showed no increase in strength. a muscle biopsy from the vastus lateralis before and after training did form part of the study’s design to investigate any changes that might have occurred from the training, but was unsuccessful due to the severe muscle atrophy and wasting. some previous research on exercise training in ibm patients reported improvements in muscle strength, whereas others showed no change.[3,4] it is important to note that the patient from the present study was severely affected by the disease, whereas most of the other reported studies excluded patients with such disease severity and thus the responses may have been different. conclusion the data from this case study showed that systematic supervised resistance exercise was safe in an advanced staged ibm patient. the training did not appear to have improved muscle strength, but could have resulted in maintained muscle function. conflict of interest and source of funding: the authors declare no conflict of interest. we would like to extend heartfelt thanks for the financial contribution towards this study from the ann kreitzer will trust and the isidore, theresa and ronald cohen charitable trust. during the study, tak was a recipient of the tim and marylin noakes post-doctoral scholarship. author contributions: cd'a: conception, design, clinical assessments and writing of paper. rj: training of participant, data collection and writing of paper. cdp: training of participant, data collection and writing of paper. ap: conception, design, overview of training of participant and writing of paper. tak: conception, design, analysis, data interpretation and writing of paper. references 1. schmidt k, schmidt j. inclusion body myositis: advancements in diagnosis, pathomechanisms, and treatment. curr opin rheumatol 2017; 29(6):632-638. [doi: 10.1097/bor.0000000000000436] [pmid: 28832349] 2. aggarwal r, oddis cv. inclusion body myositis: therapeutic approaches. degener neurol neuromuscul dis 2012; 2:43-52. [doi: 10.2147/dnnd.s19899] [pmid: 30890877] 3. spector sa, lemmer jt, koffman bm, et al. safety and efficacy of strength training in patients with sporadic inclusion body myositis. muscle nerve1997; 20(10):1242-1248. [doi:10.1002/(sici)1097-4598(199710)20:10<1242::aidmus6>3.0.co;2-c] [pmid: 9324080] 4. jørgensen an, jensen ky, nielsen jl, et al. effects of blood-flow restricted resistance training on mechanical muscle function and thigh lean mass in sibm patients. scand j med sci sports 2022; 32(2):359-371 [doi: 10.1111/sms.14079] 5. santalla a, munguía-izquierdo d, brea-alejo l, et al. feasibility of resistance training in adult mcardle patients: clinical outcomes and muscle strength and mass benefits. front aging neurosci 2014; 6:334.[doi: 10.3389/fnagi.2014.00334][pmid: 25566067] 6. greenberg sa. inclusion body myositis: clinical features and pathogenesis. nat rev rheumatol. 2019; 15(5):257-272. [doi: 10.1038/s41584-019-0186-x][pmid: 30837708] sportsmed_june04 8 sports medicine vol 16 no.2 2004 introduction aging is generally defined as a progressive loss of function, increasing susceptibility to age-related disease and an associated transition from independent to dependent lifestyle.3,9 a decline in both cognitive and motor functions is associated with increasing age.8,12 skeletal muscle force output capacity remains stable until about the age of 45 years, and then decreases by ~ 10 -15% each decade from the age of about 50 years.7,10,19 despite these negative consequences associated with aging, many people participate in sporting activities when they are 70 years and older. exercise has been shown in some studies to reduce age-related declines in strength, aerobic capacity, flexibility and physical function.14 however, while exercise can reduce the rate of decline in age-related exercise capacity, it cannot reduce the absolute effect of aging on the reduction in functional capacity.21 an examination of the changes in athletic performances associated with aging, and particularly age-group records for athletic activity, provides an assessment of the effect of age on physical performance. this analysis of athletic performance and age was first performed by bottiger1,2 and has been repeated more recently by noakes21 and spirduso.23 spirduso23 found that running performance of elite and recreational runners deteriorated from the mid-thirties, and decreased by approximately 1% per year from this point. by the age of 80 years, running performance was approximately 50% of the best performances achieved in the late 20s and early 30s. recently, it has been suggested that both high-intensity and endurance running may damage the neuromuscular system.6,16,18,24 mechanical disruption of muscle fibres caused by prolonged eccentric muscle activity has been proposed as a cause of exercise-associated muscle damage.5,13 several studies have shown that muscle damage occurs after marathon and ultramarathon races. hidika et al.11 showed that severe muscle damage with signs of fibre necrosis and inflammation occurred in muscle biopsies performed on runners after running a marathon race. in a similar study up to 25% of the muscle fibres of runners after a marathon race showed areas of myofibrillar loss.25 sherman et al.22 showed that isokinetic leg extensor strength decreased immediately after a marathon and was not fully recovered after 7 days. chambers et al.4 showed that the vertical jump height, a measure of leg extensor muscle power, was significantly decreased immediately after a 90 km race, and remained significantly lower than pre-race values for 18 days. kuipers et al.15 studied runners over a 7month period while they trained for a marathon. they found a gradual increase in degenerative changes in both type i and type ii fibres in the subjects' vastus lateralis muscles over this period. they suggested that these pathological changes were related to the total distance covered during original research article age-related decrements in cycling and running performance a st clair gibson (mb chb, phd, md) m i lambert (phd) t d noakes (mb chb, md, dsc) research unit of exercise science and sports medicine, department of human biology, university of cape town correspondence: a st clair gibson mrc/uct research unit for exercise science and sports medicine sport science institute of south africa po box 115 newlands 7725 tel: 021-650 4577 fax: 021-686 7530 e-mail: agibson@sports.uct.ac.za abstract objective. this study examined age-related decrements in athletic performance during running and cycling activities. design. the age group winning times for males aged between 18 and 70 years competing in the 1999 argus cycle tour (103 km) and 1999 comrades running marathon (90 km), south africa's premier endurance cycling and running events respectively, were examined. main outcome measures. the relationship between speed (cycling and running respectively) and age was calculated using a 4th order polynomial function. the derivative of each of these functions was determined and then the slope of the function corresponding to each age was calculated. results. the rate of decline in running speed occurred at an earlier age (~ 32 years) during the running race compared with the cycling tour (~ 55 years). conclusions. these findings establish a trend that there is ‘accelerated’ aging during running which can perhaps be attributed to the increased weight-bearing stress on the muscles during running compared with cycling. sports medicine vol 16 no.2 2004 9 running training rather than the intensity of training. it is tempting to speculate that these changes in muscle function and anatomy associated with acute or chronic training and racing bouts may cause permanent muscle damage which leads to an ‘accelerated’ aging process. indeed, noakes21 has suggested that top class marathon runners have about a 10-year period during which they can expect to perform well in their age-group. this observation can perhaps be explained by cumulative muscle pathology changes which occur after several years of training and racing marathons which results in the skeletal muscle ‘ageing’ at a faster rate than is expected. if the repeated weight-bearing eccentric activity of the locomotor muscles during running is indeed the cause of ‘accelerated’ aging, then the performance of a group of runners should show decrements in performance at an earlier age than that observed in other physically active subjects who engage in non-weight-bearing sporting activities. cycling is an example of a physical activity characterised by repetitive contractions that are not weight bearing. should this theory be correct it would be expected that muscle performance would decline with age at a faster rate in a group of runners than a group of cyclists. therefore, the aim of this study was to examine the agerelated decrements in performance in a group of competitive runners and cyclists to determine whether running caused greater decrements in performance at an earlier age than cycling. methods the race times of age-category winners for ages 18 70 years in the 1999 comrades 90 km running race and argus 103 km cycle race were obtained from the respective race organizers. these race times for each age were used for subsequent analysis. the relationship which described the line of best fit between age and running or cycling speed was calculated using graphpad prism (version 3) software (graphpad software inc., san diego, ca, usa). in both running and cycling events, a 4th order polynomial equation was used to calculate the line of best fit. the derivative of the 4th order polynomial function defining the relationship between age and running or cycling speed was subsequently calculated. using the derivative (dy/dx), the slope of this relationship for each age year was calculated. a negative value indicated that running or cycling times were decreasing (or speed increasing) compared with the previous year, while a positive value indicated that the running or cycling time for the respective events had increased, or that speed had decreased compared with the previous year of age. the magnitude of the value (positive or negative) indicates the extent of the change in speed compared with the previous year. results in 1999, 11 285 individuals completed the 1999 comrades 90 km running marathon, and 28 440 individuals completed the argus 103 km cycling race. the fastest time for the 90 km running marathon was 5 h 30 min 10 s by a 32-year-old competitor. the fastest time for the cycling race was 2 h 31 min 26 s by a 24-year-old competitor. twelve other age categories were given similar finishing times for the cycling race, the oldest being a 36-year-old individual (ages 19 20, 22 27, 29 31, 34, 36). the 4th order polynomial function equation describing the line of best fit for race time vs. age for the running marathon was: y = 1173 – 67.82x + 1.919x2 – 0.02229x3 + 0.0001226x4 (r2 = 0.85, fig. 1a), where y = race time (min) and x = age (years). the 4th order polynomial function equation describing the line of best fit for race time vs. age for the cycle race was: y = 317 – 19.01x + 0.7605x2 – 0.01257x3 + 0.00007571x4 (r2 = 0.90, fig. 1b), where y = race time (min) and x = age (years). using the derivative of the 4th order polynomial function, the rate of change of race time was calculated for each year. the differential equations were solved for age and the resulting curves for the running marathon (fig. 2a) and for the cycle tour (fig. 2b) were plotted. the rate of decline occurred at an earlier age (~ 32 years) during the running race compared with the cycling race (~ 55 years). while the rate of improvement in running time was maintained until age ~ 32, and declined at an increasing rate after this age, there was 0 10 20 30 40 50 60 70 80 0 125 250 375 500 625 750 (a) t im e ( m in ) age (years) 0 10 20 30 40 50 60 70 80 0 50 100 150 200 250 300 (b) t im e ( m in ) age (years) fig. 1. age-related changes in race time (min) for the comrades 90 km running marathon (a) and for the argus 103 km cycle tour (b). minimal change in cycling time until age ~ 55, after which time rate of change in cycling time increased. discussion the important finding from this study was that the age-related decrements in performance began at an earlier age in runners compared with cyclists. in the runners, there was an improvement in performance until age 32 years, and thereafter there was a marked decrement in performance. the rate of decrease in performance accelerated with increasing age. in contrast, the cyclists generally maintained performance until age 55 years. thereafter, performance declined, with the rate of decline increasing with increasing age, similar to that found in the runners at an earlier age. one may therefore postulate that running causes more profound changes in anatomical structures and physiological mechanisms necessary to maintain pacing strategies during racing, and may lead to ‘accelerated’ aging. another interpretation is that the stresses associated with training and racing induce changes which prevent the athlete from sustaining a high training volume, and it is this reduced training volume which causes the reduction in performance. cycling is a non-weight-bearing activity, with little or no eccentric activity in contrast to that found during running, where marked eccentric activity is necessary to maintain an upright posture against gravitational forces, and where eccentric activity is part of the stretch-shortening cycle which makes up part of the normal energy transfer during weight-bearing activity.20 a large body of work has shown that eccentric activity causes muscle damage, and that this muscle damage is found after marathon and ultramarathon running.4,11,15,22,25 in contrast, no studies have shown similar pathology in cyclists after endurance cycling events. therefore, it is reasonable to speculate that the decrements in age-related running times may have been caused by chronic muscle or musculoskeletal damage and perhaps ‘premature aging’ of the lower limb muscles of older runners, due to the cumulative effects of years of biomechanical stress and eccentric activity related to running training and racing. interestingly, spirduso23 showed that age-related decrements in rowing performance occur at age ~ 45 years. as rowing is also a non-weight-bearing activity using predominantly upper body muscles, and as the age-related decrements in performance also occurred at a later age than in the runners in our study, the findings of spirduso23 support the hypothesis that running as a sport in particular may cause ‘accelerated’ aging of muscle function in the legs. a further reason for the decrement in performance may have been that the veteran runners trained less than the younger runners, and that this difference in training volume may be the cause of the decrements in their performance. lambert and keytel17 similarly showed that the age-related decrements in performance during a 56 km marathon began at age 28 in men and age 32 in women. they suggested that these decrements in performance were related to training volume, with the older runners running less distances per week than the younger runners. further work is needed to examine this suggestion. another reason for the differences in age-related decrements in performance between running and cycling activities may be due to the nature of cycling racing itself. bunch riding and drafting (slipstreaming) is common in cycling and thus the older cyclists may have been able to produce the maintained level of performance by drafting behind younger cyclists, or by staying in a competitive bunch which would require less absolute work to be performed by the veteran cyclists.23 this may have explained why several age categories had similar times for the cycle race. it must be noted that the duration of the cycling and running tests were different, with the winning times of the cycle race being 2h 31 min and running marathon 5 h 30 min. therefore, the greater decrements in performance in the runners may have been related to the longer duration of the running race. the older runners may have adopted different pacing strategies during the longer duration running race than the cyclists did in their race. the pacing strategies may have been alike if the duration of the two events had been more similar. however, lambert and keytel17 showed that the performance decrements occurred in runners at age 40 or younger in race distances ranging from 10 km to 56 km, which would be of the same time period or shorter than that of the cycle race in this study. therefore, it is unlikely that the differences in the decrement in performance with age 10 sports medicine vol 16 no.2 2004 10 20 30 40 50 60 70 80 -20 -10 0 10 20 (a ) s lo p e ( m in /y e a r) age (years) 10 20 30 40 50 60 70 80 -20 -10 0 10 20 (b) age (years) s lo p e ( m in /y e a r) fig. 2. the rate of change of speed for each age for the comrades 90 km running marathon (a) and the argus 103 km cycle tour (b). a positive slope represents a slower time compared with the previous year. sports medicine vol 16 no.2 2004 11 between runners and cyclists were due solely to the differences in duration of the running and cycling races. it must also be noted that the age point at which performance declined in both groups has been described in an approximate manner. with further statistical analysis using differential equations a more exact age deflection point may have been determined. however, we did not wish to overinterpret our data, given that this was essentially a descriptive study of finishing times for the two races which were given to us by the race organizers, and therefore we have been deliberately conservative in the analysis of our data. finally, a further finding was that the rate of improvement in performance was greater in younger age categories in runners compared with cyclists. it is not clear whether these differences were also caused by the ability of younger cyclists to benefit from the different pacing strategies involved in cycling, or whether differences were due to more time being necessary for a younger individual to adapt to the biomechanical and physiological stresses associated with running. conclusion in conclusion, this study established a trend that age-related decrements in performance occur at an earlier age in running compared with cycling in the specific races used in this study. it is tempting to speculate therefore that running causes more muscle damage which leads to premature aging of the muscles at a younger age than that which occurs in cycling. further work is necessary to examine these different causes of age-related decrements in performance found in this and other studies. the trend identified in this study has clinical relevance and physicians should consider the possibility of a premature muscle aging process induced by running in runners in their fourth and fifth decades presenting with symptoms of reduced exercise tolerance. acknowledgements the medical research council of south africa, national research foundation of south africa, and the harry crossley research fund of the university of cape town provided financial assistance for this study. references 1. bottiger le. physical working capacity and age. acta med scand 1971; 190: 359-62. 2. bottiger le. regular decline in physical working capacity with age. bmj 1973; 3: 270-1. 3. cannon j, tarpenning k, kay d, marino fe. ageing is not associated with a decline in neuromuscular innervation or reduced specific force in men aged 20 and 50 years. clin physiol 2001; 21: 350-7. 4. chambers c, noakes td, lambert ev, lambert mi. time course of recovery of vertical jump height and heart rate vs. running speed after a 90 km foot race. j sports sci 1998; 16: 645-51. 5. clarkson pm, sayers sp. etiology of exercise-induced muscle damage. can j appl physiol 1999; 24: 234-8. 6. derman ew, schwellnus mp, lambert mi, et al. the 'worn-out athlete': a clinical approach to chronic fatigue in athletes. j sports sci 1997; 15: 34151. 7. doherty tj, vandervoort aa, brown wf. effects of ageing on the motor unit: a brief review. can j appl physiol 1993; 18: 331-58. 8. dustman re, emmerson ry, shearer de. life span changes in electrophysiological measures of inhibition. brain cogn 1996; 30: 109-26. 9. grabiner md, enoka rm. change in movement capabilities with aging. exerc sport sci rev 1995; 23: 65-104. 10. hakkinen k, kraemer wj, kallinen m, linnamo v, pastinen um, newton ru. bilateral and unilateral neuromuscular function and muscle cross sectional area in middle-aged and elderly men and women. j gerontol a biol sci med sci 1996; 51: 21-9. 11. hikida rs, staron rs, hagerman fc, sherman wm, costill dl. muscle fibre necrosis associated with human marathon runners. j neurol sci 1983; 59: 185-203. 12. hillman ch, weiss ep, hagberg jm, hatfield bd. the relationship of age and cardiovascular fitness to cognitive and motor processes. psychophysiology 2002; 39: 303-12. 13. jones da, round jm. skeletal muscle in health and disease. manchester: manchester university press; 1990. 14. keysor jj, jette am. have we oversold the benefit of late-life exercise? j gerontol a biol sci med sci 2001; 56: 412-23. 15. kuipers h, janssen gme, bosman f, frederik pm, geurten p. structural and ultrastructural changes in skeletal muscle associated with long-distance training and running. int j sports med 1989; 10: suppl 3, s156-9. 16. lambert mi, st clair gibson a, derman ew, td noakes. regeneration after ultra-endurance exercise. in: lehmann m, steinakcer jm, gastmann u, eds. overload, performance incompetence, and regeneration in sport. new york: kluwer academic/plenum publishing corporation, 1999: 163-72. 17. lambert mi, keytel l. training habits of top male and female two oceans runners. south african journal of sports medicine 2000; 7: 27-37. 18. lambert mi, bryer l, hampson db, et al. accelerated decline in running performance in a masters runner with a history of a large volume of training and racing. journal of aging and physical activity 2002; 10: 14-21. 19. larsson l, sjodin b; karlsson j. histochemical and biochemical changes in human skeletal muscle with age in sedentary males. acta physiol scand 1978; 103: 31-9. 20. nicol c, komi pv, marconnet p. fatigue effects of marathon running on neuromuscular performance. i. changes in muscle force and stiffness characteristics. scand j med sci sports 1991; 1: 10 -7. 21. noakes td. lore of running. cape town: oxford university press, 2001. 22. sherman wm, costill dl, fink wj, hagerman fc, armstrong le, murray tf. effect of a 42.2 km footrace and subsequent rest or exercise on muscle glycogen and enzymes. j appl physiol 1983; 55: 1219-24. 23. spirduso ww. physical dimension of aging. champaign, ill.: usa. human kinetics, 1995: 389-417. 24. st clair gibson a, lambert mi, weston ar, et al. exercise-induced mitochondrial dysfunction in an elite athlete. clin j sport med 1998; 8: 52-5. 25. warhol mj, siegel aj, evans wj, silverman lm. skeletal muscle injury and repair in marathon runners after competition. am j pathol 1985; 118: 331-9 sajsm vol 18 no.2 2006 31 introduction progesterone increases resting minute ventilation (ve) by central neural mechanisms in the luteal phase and oestrogen potentiates this action through induction of progesterone receptors in the hypothalamus. 1 in addition, progesterone increases chemosensitivity, as noted by an increase in the ventilatory response to hypoxia and hypercapnia during the luteal phase compared with the follicular phase 6,11 or in men treated with medroxyprogesterone acetate (mpa). 4 however, this is not consistently reported, as a recent study did not find an increase in chemosensitivty in the mid-luteal (ml) phase compared with the early follicular (ef) phase. 2 furthermore, an increase in body temperature is also known to elevate ve and thus the elevated body temperature associated with the luteal phase may also contribute to the observed hyperventilation. 11 the effect of elevated progesterone levels on ve during exercise remains equivocal. a number of studies have observed an increase in the ventilatory equivalent (the ratio of ve to vo2) or a decrease in the end tidal partial pressure of carbon dioxide during incremental exercise to exhaustion in the luteal phase versus the follicular phase or with mpa supplementation in males versus control condition. 4,6,9,11,12 however, others have found no difference in ve during maximal 3,10 or submaximal exercise. 2,5,8,9 beidleman et al. viewed a progesterone-induced increase in ve to be a potential benefit for athletes when exercising at altitude by possibly causing an increase in oxygen delivery to muscle. 2 however, they found no improvements in vo2max or endurance capacity at altitude despite a small increase in oxygen saturation (3%) in the ml phase compared with the ef phase. 2 others view an increased ventilatory response to hypoxia and hypercapnia or to exercise to be deleterious for athletic performance due to the heightened sensation of original research article influence of menstrual phase on ventilatory responses to submaximal exercise t oosthuyse (bsc hons)1 a n bosch (phd)2 1 school of physiology, university of the witwatersrand medical school, johannesburg 2 uct/mrc research unit for exercise science and sports medicine, university of cape town conclusions. the change in ventilatory parameters from ef to ml phase is related to the ovarian hormone concentrations. therefore inter-individual variability should be considered in menstrual phase comparative studies. furthermore, the persistently higher rr noted during exercise in the ml phase did not increase metabolic rate, and is therefore not expected to affect rate of fatigue significantly, even during prolonged exercise. abstract objectives. to determine whether an increase in respiratory drive, due to elevated progesterone and oestrogen concentration during various menstrual phases, persists throughout prolonged submaximal exercise and potentially contributes to fatigue. furthermore, to determine whether the difference in the ventilatory response to exercise from one menstrual phase to another is correlated to the ovarian hormone concentrations. design. we compared the change in ventilatory para meters during 90 min exercise at 60%vo2max between the early follicular (ef) and mid-luteal (ml) phase (n = 9) and between the ef and late follicular (lf) phase (n = 5) in eumenorrhoeic women. main outcome measures. menstrual phase comparisons and correlations between the change in ventilatory parameters (minute ventilation (ve), respiratory rate (rr), tidal volume) from the ef to ml or from the ef to lf phase and ovarian hormone concentration. results. the difference in rr between ef and ml phases correlated to progesterone concentration in the ml phase (r = 0.7, p = 0.04). in addition, rr was higher during exercise in the ml compared with ef phase for the full duration of exercise by on average 2.3 ± 2.1 breaths/min (p < 0.05). however, no difference in submaximal vo2 between menstrual phases was evident. no significant difference in exercising-ve was observed between menstrual phases, but the change in ve from ef to ml correlated to oestrogen (r = 0.8, p = 0.02) and progesterone (r = 0.7, p = 0.04) concentration in the ml phase. correspondence: a n bosch uct/mrc research unit for exercise and sports medicine university of cape town sports science institute of sa boundary rd newlands, cape town tel: 021-650 4578 fax: 021-686 7530 e-mail: abosch@sports.uct.ac.za sajsm vol 18 no.2 2006 31 pg31-37.indd 31 6/28/06 1:49:23 pm 32 sajsm vol 18 no.2 2006 dyspnoea that could limit exercise performance. 11 schoene et al. is the only study to report a difference in exercise performance with a coincident increase in ve in the luteal phase versus follicular phase when they observed a shorter time to exhaustion during a maximal ramp test in the luteal phase in non-athletes only. 11 however, an elevated ve during exercise in the luteal phase in endurance athletes did not compromise maximal time to exhaustion. 11 therefore, the negative effects of an increase in ve during exercise due to progesterone can be overcome with training. most menstrual phase comparative studies reporting respiratory variables include exercise sessions shorter than 40 minutes. 3-6,10-12 it would be interesting to investigate whether respiratory differences persist over a longer period of exercise as a prolonged increase in respiratory rate may contribute to fatigue and thereby hamper endurance performance. therefore, we aimed to compare respiratory variables during prolonged submaximal exercise between menstrual phases. the main focus was a comparison between the ef and ml phase, as the most pronounced difference would be expected between theses phases where progesterone increases from the lowest level in the ef phase to the highest level in the ml phase. furthermore, the increase in progesterone in the ml phase coincides with a luteal phase peak in oestrogen and, as mentioned earlier, oestrogen potentiates the increased respiratory drive associated with progesterone. 1 however, even higher oestrogen concentrations occur in the pre-ovulatory period (referred to as the late follicular (lf) phase) albeit with low but rising progesterone concentrations, making this an interesting phase to consider. therefore we included a sub-sample group comparison between the ef and the lf phase. the latter menstrual phase is often overlooked, particularly in the longer duration exercise studies. while hackney et al. claimed to include the lf phase in such a comparison, they reported an average progesterone concentration of 10 nmol/l, 8 which exceeds the 5 nmol/l limit for this menstrual phase and would rather suggest a post-ovulatory period. williams and krahenbuhl, who observed a significant increase in ventilation rate during short-duration submaximal exercise only at the peak of the progesterone increase in the luteal phase compared with the ef phase, suggest that the inconsistent findings of menstrual phase differences in ve are due to studies not controlling the menstrual phase timing of testing tightly enough. 12 lastly, we intend to investigate whether the change in ventilatory parameters observed from the ef to lf or ml phase can be correlated to the oestrogen and progesterone concentration, or the magnitude of the increase in these hormones from the ef phase to either lf or ml phase or the oestrogen to progesterone ratio. previous studies have been unable to identify relationships between the ovarian hormone concentration and ventilation, 2 but only considered absolute values for ventilatory parameters instead of increasing the sensitivity of the analysis by rather considering the change in the parameter from one phase to the next. methods a total of 10 subjects where included in this study (table i). all subjects where young, healthy medical students who experienced regular menstrual cycles and where classified as sedentary as none participated in regular exercise training and performed less than 2 hours of coincidental exercise per week. subjects were all non-smokers and had not taken oral contraceptives for at least 1 year before their participation in this study. the study protocol was granted ethical clearance by the committee for research in human subjects at the university of the witwatersrand. all subjects gave written consent to participate in the study after the protocol had been carefully explained. preliminary screening maximal aerobic capacity a discontinuous vo2max test was performed on a stationary bicycle ergometer (excalibur 911 900, lode, groningen, netherlands). a discontinuous protocol was chosen as it is well tolerated by sedentary subjects and is reported to produce a vo2max value that is comparable to a continuous protocol. 7 after a 10-minute warm-up subjects performed 3-minute exercise bouts starting at 100 watts and increasing in increments of 20 watts interspersed by recovery periods. during the recovery period subjects were allowed to rest for as long as they felt necessary (10 20 minutes) or until their heart rate returned to 100 beats/min. during the 3-minute exercise bout subjects breathed through a one-way valve mouthpiece that allowed them to inhale atmospheric air and all expired air was directed through a 3 l mixing chamber into a metabolic cart system (oxycon-4, mijnhardt, bunnik, netherlands). the oxygen and carbon dioxide analysers were zeroed using 100% nitrogen gas and calibrated using commercially available gas mixture of known o2 and co2 content and room air. the system calculated and produced readings of vo2 and vco2 from conventional equations every 30 seconds. vo2max was considered to have been attained when vo2 differed by less than 1.5 ml/kg/min between successive workloads. menstrual cycle characteristics subjects recorded their basal oral temperature each morning immediately after waking using a digital thermometer (vital sign vs-10 soar corporation, japan) accurate to 0.1°c, in order to identify a biphasic temperature pattern that often characterises a eumenorrhoeic cycle. the timing of the luteinising hormone (lh) surge that induces ovulation was predicted using a home ovulation test (clearplan, unipath ltd., bedford, england). subjects exposed the tester to midurine flow of their first morning urine sample starting on the day corresponding to the total number of days in their menstrual cycle minus 15, and continued each morning until a positive result was recorded. pg31-37.indd 32 6/28/06 1:49:23 pm sajsm vol 18 no.2 2006 33 experimental protocol each subject completed two or three sessions of 90 minutes of cycling exercise at 60% vo2max during different phases of the menstrual cycle. the menstrual phases included: (i) ef: 2 8 days after the onset of menses; (ii) lf: 2 days before up to the day of a positive lh surge recording; and (iii) ml: 4 10 days after a positive lh surge reading. all 10 subjects performed the experimental trial once in their ef phase, 9 of the subjects performed a ml phase trial and 6 subjects performed a lf phase trial. a resting blood sample was taken on the day of each trial for the measurement of serum progesterone and oestrogen concentration (coat-a-count, diagnostic products corporation, los angeles, ca), thereby confirming the subject’s menstrual phase. all samples from each subject were analysed in the same assay and intra-assay coefficient of variation was 5.3% and 4.7% for oestrogen and progesterone respectively. the accepted range for oestrogen and progesterone concentrations for each menstrual phase were, respectively, 37 220 pmol/l and < 3 nmol/l for the ef phase, 360 -1 377 pmol/l and < 5 nmol/l for the lf phase, and 220 955 pmol/l and > 10 nmol/l for the ml phase for oestrogen and progesterone respectively (coat-a-count, diagnostic products corporation, los angeles, ca). if the measured ovarian hormone concentration fell outside of these acceptable ranges for a particular trial, that trial was excluded from the data analysis. each subject performed all trials at the same time of day and the ordering of the trials was randomised with respect to menstrual phase. all experimental trials could not always be completed in the same menstrual cycle – the trial was then completed over two successive cycles. for 48 hours before the first trial each subject kept a record of all their meals and was asked to follow the same diet as closely as possible before the subsequent trial. two hours before arrival at the laboratory subjects ate a packed meal (2 062 kj) consisting of a 175 ml yoghurt, 175 ml orange juice and 30 g granola bar, providing in total 74 g of carbohydrate, 14 g of fat and 12 g of protein. subjects were asked to refrain from caffeinated foods and beverages on the day of the trial. on arrival at the laboratory, body mass was recorded and subjects rested for approximately 20 minutes while seated before a resting blood sample was taken and respiratory and indirect calorimetry measurements were recorded (oxycon-4, mijnhardt, bunnik, netherlands) for 4 minutes. subjects then began cycling at 60% vo2max on the same bicycle ergometer as used in the vo2max test. respiratory measurements were recorded at 15-minute intervals for 3 minutes during the 90 minutes of exercise. the respiratory variables measured included: minute ventilation (ve), tidal volume, respiratory rate (rr), oxygen consumption and metabolic equivalents (mets). statistical analysis a paired t test was used to identify differences in ventilatory parameters between menstrual phases in the ef/ml group and ef/lf group. pearson’s linear regression analysis was conducted to identify relationships between the change in respiratory variables from the ef phase to lf/ml phase and the logarithm of oestrogen and progesterone concentration in the lf/ml phase or the logarithm of the oestrogen to progesterone (e/p) ratio in the ml phase or the magnitude of the increase in oestrogen from ef to lf/ml phase (e-fold) or the magnitude of increase in progesterone from ef to ml phase (p-fold). data are presented as mean ± standard deviation and significance was accepted as p < 0.05. table i. subject characteristics mean ± sd sample size 10 age (years) 23.1 ± 1.9 body mass (kg) 55.6 ± 7.5 height (cm) 160.8 ± 6.7 length of mc (days) 27.6 ± 1.8 day of ovulation 14.2 ± 2.3 vo2max (ml/kg/min) 29.4 ± 2.1 submaximal exercise intensity (% vo2max) 60.2 ± 3.0 submaximal workload (watts) 51.5 ± 14.2 sd = standard deviation; mc = menstrual cycle. table ii. resting ovarian hormone concentration profile for the respective menstrual phases ef lf n = 5 oestrogen (pmol/l) 133.1 ± 54.4 1191 ± 810 progesterone (nmol/l) 1.8 ± 0.4 3.9 ± 1.1 e-fold 10.3 ± 6.9 ef ml n = 9 oestrogen (pmol/l) 137.7 ± 67.1 641.3 ± 218 progesterone (nmol/l) 1.8 ± 0.7 4 5.5 ± 20.3 e/p ratio (pmol/nmol)* 16.13 ± 7.8 e-fold 5.3 ± 2.6 p-fold* 25.1 ± 12.2 ef = early follicular; lf = late follicular; ml = mid-luteal; e-fold = the magnitude of increase in oestrogen concentration above the ef phase; p-fold = the magnitude of increase in progesterone concentration above the ef phase; e/p ratio = oestrogen to progesterone concentration ratio. *variables that are only relevant for the ml phase as this phase coincides with appreciable increases in progesterone. pg31-37.indd 33 6/28/06 1:49:23 pm 34 sajsm vol 18 no.2 2006 results all subjects successfully detected a positive reading on the urine lh test, indicating that they all experience ovulatory cycles. the serum oestrogen and progesterone concentration measured on the day of each trial confirmed that all subjects were in the correct menstrual phase (table ii), except the lf phase trial of 1 subject, and all data from this trial were therefore excluded. comparisons between menstrual phases no significant difference was observed in minute ventilation expressed in absolute values (l/min) (fig. 1a & b) or relative to vo2 as ventilatory equivalent (data not shown) between the ef and lf or the ef and ml phases at rest or during any time interval during 90 minutes of submaximal exercise. no significant difference was noted in the resting respiratory rate in the ef and lf or ef and ml phase. furthermore, no difference was observed in respiratory rate at any time interval during exercise between the ef and lf phase (fig. 1c), but a significantly higher respiratory rate was recorded during exercise at all time intervals in the ml phase compared with the ef phase (fig. 1d). resting tidal volume was unchanged between ef and lf or ef and ml phase and at all time intervals during submaximal exercise between the ef and ml phase (fig. 1 e-f). however, tidal volume tended to be significantly less in the lf phase compared with the ef phase during submaximal exercise when considering the average over 30 90 minutes (p = 0.054) and 60 90 minutes (p = 0.065) of the exercise period (fig. 1e). no significant differences where observed between menstrual phases for mets or absolute vo2 (l/min) at rest or during exercise (fig. g-h). test for correlations between ventilatory parameters and ovarian hormones no significant correlation was identified between ventilatory parameters, expressed as absolute values and ovarian hormone concentrations. however, when considering the change in a parameter from the ef phase to the lf and ml phase, significant correlations where identified, but only with the change from the ef to ml phase. that is, the change in minute ventilation from the ef to ml phase correlated positively with the magnitude of increase in oestrogen from ef to ml (e-fold) (fig. 2a-c). furthermore, the change in respiratory rate from ef to ml also correlated positively with the progesterone concentration in the ml phase (fig. 3a). however, we observed a negative correlation between the change in respiratory rate from ef to ml phase and the e/p ratio (fig. 3b). discussion the most important finding of this study is that the variability in respiratory drive between menstrual phases during submaximal exercise is related to the individual’s oestrogen and progesterone concentration on the day. the current study observed an increase in respiratory rate during exercise in the ml phase compared with the ef phase. most previous studies use only minute ventilation or ventilatory equivalents as a means of comparing respiratory drive during exercise between menstrual phases, 2-6,8-12 and do not consider the contributing variables, respiratory rate or tidal volume. furthermore, most previous reports have only evaluated ventilatory drive over short exercise periods 3-6,10-12 whereas the current study demonstrated that the increase in respiratory rate during exercise in the ml phase continued to persist throughout a prolonged exercise period. furthermore, this is the first study to demonstrate a significant relationship between respiratory rate and the circulating progesterone concentration. unlike previous studies that found no significant correlations between the ventilatory response to exercise and ovarian hormones, 2 we considered the change in the ventilatory parameter between menstrual phases, and so isolated the influence of the intervention (being menstrual phase), thereby increasing the sensitivity of the analysis. moreover, the negative correlation observed between the change in respiratory rate and the e/p ratio does not contradict the significant positive relationship identified between the change in respiratory rate and progesterone concentration, but in fact supports it. that is, a high e/p ratio could be a result of a high oestrogen concentration but low progesterone concentration and thus the lower progesterone concentration would result in less of a difference in respiratory rate between the ef and the ml phase, whereas a low e/p ratio could be a result of a relatively high progesterone concentration and thus a marked increase in respiratory rate from ef to ml phase. nonetheless, the average increase in respiratory rate in the ml phase relative to the ef phase was only 2.3 ± 2.1 breaths/min (ranging between 0.13 and 5.6 breaths/ min) and this extra demand on respiratory muscles did not significantly increase metabolic demand, as demonstrated by a similar rate of oxygen consumption between the ef and ml phase. we further tested the effect of this change in respiratory rate from ef to ml phase on metabolic rate, by testing for a correlation between the change in oxygen consumption from ef to ml and the change in respiratory rate or minute ventilation from ef to ml phase and found no significant relationships (data not shown). therefore we would expect that the slightly greater work demand on the inspiratory muscles in the ml phase would have a negligible effect on rate of fatigue or exercise performance, even during prolonged exercise. furthermore, the increase in respiratory rate during exercise in the ml phase of the current study did not appear to have a significant influence on minute ventilation. in contrast, some previous studies have observed greater minute ventilation during exercise in the luteal phase compared with the follicular phase, 4,6,9,11,12 but this has not been consistently reported. 2,3,5,8,10 however, despite the finding of no difference in minute ventilation between ef and ml in this current study and no significant correlation between absolute pg31-37.indd 34 6/28/06 1:49:23 pm sajsm vol 18 no.2 2006 35 fig. 1. comparison of the following ventilatory parameters (mean and standard deviation): minute ventilation (a and b); respiratory rate (c and d); tidal volume (e and f); and oxygen consumption (g and h), at rest and averaged over 30-minute time intervals during 90 minutes of submaximal exercise between either the ef and lf or ef and ml phases. * and ** denotes significance between identified menstrual phases with p ≤ 0.05 and p < 0.02, respectively. + denotes a trend for a difference between identified menstrual phases p = 0.065. pg31-37.indd 35 6/28/06 1:49:24 pm 36 sajsm vol 18 no.2 2006 minute ventilation and ovarian hormones, we did observe a significant relationship in the change in minute ventilation from ef to ml and the oestrogen and progesterone concentration, and the magnitude of increase in oestrogen between these menstrual phases. we therefore suspect that individual variability in the increase in oestrogen and progesterone in the ml phase may explain the inconsistency in the literature regarding menstrual phase variation in ventilation during exercise. furthermore, the significant correlations observed with not only progesterone concentration but also oestrogen and degree of increases in oestrogen are supposedly related to earlier reports describing progesterone’s dependence on oestrogen in order to cause the heightened ventilatory response. 1 the lf phase characterised by the preovulatory surge in oestrogen with no or minor increases in progesterone did not appear to influence respiratory rate or minute ventilation. however, it is possible that the major peak in oestrogen during this pre-ovulatory phase may prime the hypothalamic nuclei cells for progesterone receptor induction and so facilitate the ventilatory response in the luteal phase. the sample sizes employed in the current study may be considered relatively small and the possibility of incurring a type i error in the interpretation of the significant correlations must be considered. however, the relation identified in the current study between the ventilatory response to exercise and the ovarian hormones is not just based on a single fig. 3. significant correlations identified between the change in respiratory rate from the ef to ml phase during submaximal exercise and the logarithmic function of progesterone concentration (a) and the logarithmic function of the oestrogen to progesterone (e/p) ratio (b) in the ml phase. fig. 2. significant correlations identified between the change in minute ventilation from the ef to ml phase during submaximal exercise and the magnitude of increase in oestrogen concentration from the ef to ml phase (e-fold) (a); logarithmic function of oestrogen concentration (b); and logarithmic function of progesterone concentration (c) in the ml phase. pg31-37.indd 36 6/28/06 1:49:25 pm sajsm vol 18 no.2 2006 37 significant correlation. rather, a number of significant correlations were identified, with not just one ventilatory parameter, but with both changes in minute ventilation and respiratory rate from the ef to ml phase when related to not only just (say) progesterone concentration but also oestrogen concentration or e/p or e-fold. therefore it is unlikely that all of these relations were identified by chance. the tendency for tidal volume during exercise to be less in the lf phase compared with the ef phase is unexpected and remains unexplained. however, in our small sample group the observed difference in tidal volume did not have a significant effect on minute ventilation. future studies should investigate respiratory responses to prolonged exercise in the lf phase employing a larger sample size. the overriding evidence for a greater ventilatory response at rest in the luteal phase versus the follicular phase 1,11,12 was not evident in the current study. however, the premeasurement resting period (which was not always strictly regulated) and the short recording interval may have been insufficient to establish a true resting reading and so a nonsteady-state condition may have obscured our comparison at rest. in conclusion, the current study supports reports of greater ventilatory drive in the ml phase compared with the ef phase during submaximal exercise. we noted that the response persists during prolonged exercise but nonetheless the increased demand on respiratory muscle is small and we expect that it should not exacerbate fatigue. furthermore, the change in ventilatory response during submaximal exercise between the ef and ml phase is related to both the oestrogen and progesterone concentration and thus both of the ovarian hormone concentrations determine the response of an individual in the luteal phase. therefore inter-individual variability in ovarian hormone concentration must be considered when studying ventilatory responses in women. acknowledgements this study was funded by the medical research council of south africa and the university of the witwatersrand research committee. references 1. bayliss da, millhorn de. central neural mechanisms of progesterone action: application to the respiratory system. j appl physiol 1992; 73: 393404. 2. beidleman ba, rock pb, muza sr, fulco cs, forte va jr, cymerman a. exercise ve and physical performance at altitude are not affected by menstrual cycle phase. j appl physiol 1999; 86: 1519-26. 3. bemben da, salm pc, salm aj. ventilatory and blood lactate responses to maximal treadmill exercise during the menstrual cycle. j sports med phys fitness 1995; 35: 257-62. 4. bonekat hw, dombovy ml, staats ba. progesterone-induced changes in exercise performance and ventilatory response. med sci sports exerc 1987; 19: 118-23. 5. de souza mj, maguire ms, rubin k, maresh cm. effects of menstrual phase and amenorrhea on exercise responses in runners. med sci sports exerc 1990; 22: 575-80. 6. dombovy ml, bonekat hw, williams tj, staats ba. exercise performance and ventilatory response in the menstrual cycle. med sci sport exerc 1987; 19: 111-7. 7. duncan ge, howley et, johnson bn. applicability of vo2max criteria: discontinuous versus continuous protocols. med sci sports exerc 1997; 29: 2738. 8. hackney ac, curley cs, nicklas bj. physiological responses to submaximal exercise at the mid-follicular, ovulatory and mid-luteal phases of the menstrual cycle. scand j med sci sports 1991; 1: 94-8. 9. jurkowski jeh, jones nl, toews cj, sutton jr. effects of menstrual cycle on blood lactate, o2 delivery, and performance during exercise. j appl physiol 1981; 51: 1439-99. 10. lebrun cm, mckenzie dc, prior jc, taunton je. effects of menstrual cycle phase on athletic performance. med sci sports exerc 1995; 27: 43744. 11. schoene rb, robertson ht, pierson dj, peterson ap. respiratory drives and exercise in menstrual cycles of athletic and nonathletic women. j appl physiol 1981; 50: 1300-5. 12. williams tj, krahenbuhl gs. menstrual cycle phase and running economy med sci sports exerc 1997; 29: 1609-18. pg31-37.indd 37 6/28/06 1:49:25 pm 14 sajsm vol 18 no. 1 2006 introduction the session rating of perceived exertion (rpe) method of monitoring exercise intensity was developed in 1995 10 as a modification of the category ratio (cr) rpe method. 2,3,19,20,22 the modification involved asking the subject to give a global rating of the perceived exertion for the entire exercise session ~30 minutes after the conclusion of an exercise bout rather than rating the momentary level of exertion as is the usual practice with rpe. 2,3,19,20,22 at that time, limited objective data were presented in support of the validity of the technique, on the basis of both heart rate (hr) and blood lactate responses. in the subsequent decade, several papers have used the session rpe method in a variety of settings and have demonstrated its value relative to quantifying exercise training intensities 4,7,8,9,16,17,23 and as the intensity component of larger schemes of evaluating training programmes. 6,7,10,11,13,21 most notably, the session rpe method has been used to demonstrate inconsistencies between the training programmes designed by coaches and executed by athletes, 11 thus providing a plausible explanation for the incidence of overtraining syndrome in high-level athletes. 6 however, the validity of the session rpe method has not been systematically tested against accepted objective methods of measuring exercise training intensity, such as %vo2peak, %hrpeak, and %hrreserve; nor has the reliability of the method been demonstrated. accordingly, the purpose of this study was to evaluate the validity and reliability of the session rpe method. original research article validity and reliability of the session rpe method for monitoring exercise training intensity l herman (ms)1 c foster (phd, facsm)1 m a maher (phd)2 r p mikat (phd, facsm)1 j p porcari (phd, facsm)1 1 department of exercise and sport science, university of wisconsin-la crosse, usa 2 department of biology, university of wisconsin-la crosse, usa abstract objective. the session rating of perceived extertion (rpe) is a method of measuring exercise intensity that may be useful for the quantitative assessment of exercise training programmes. however, there are inadequate data regarding the validity and reliability of the session rpe method. this study was designed to evaluate both the validity and reliability of the session rpe method in comparison to objective measures (%hrpeak, %hrreserve and %vo2peak) of exercise intensity. methods. fourteen healthy volunteers (7 male, 7 female) performed 6 randomly ordered 30-minute constant-load exercise bouts at 3 different intensities, with each intensity being repeated. oxygen consumption (vo2) and heart rate (hr) were measured throughout each exercise bout and normalised to maximal values obtained during a preliminary maximal exercise test. thirty minutes following the conclusion of each exercise bout, the subject rated the global intensity of the bout using a modification of the category ratio (cr) (0 10) rpe scale. this rating was compared to the mean value of objectively measured exercise intensity across the duration of the bout. results. there were significant non-linear relationships between session rpe and %vo2peak (r 2 = 0.76), %hrpeak (r 2 = 0.74) and %hrreserve (r 2 = 0.71). there were no significant differences between test and retest values of %vo2peak, %hrpeak, %hrreserve and session rpe during the easy (47 v. 47%, 65 v. 66%, 47 v. 48% and 2.0 v. 1.9), moderate (69 v. 70%, 83 v. 84%, 74 v. 75%, and 4.2 v. correspondence: c foster department of exercise and sport science university of wisconsin-la crosse la crosse, wi 54601 tel: 54601608-785 8687 fax: 54601608-785 8172 e-mail: foster.carl@uwlax.edu 4.3) and hard (81 v. 81%, 94 v. 94%, 91 v. 91% and 7.3 v. 7.4) exercise bouts. correlations between repeated bouts for %vo2peak (r = 0.98), %hrpeak (r = 0.98), %hrreserve (r = 0.98) and session rpe (r = 0.88) were significant and strong. conclusions. the results support the validity and reliability of the session rpe method of monitoring exercise intensity, although as might be predicted for a subjective method the session rpe was less precise than the objective measures of exercise training intensity. validity and reliability.indd 14 3/13/06 2:59:33 pm sajsm vol 18 no. 1 2006 15 methods the subjects were 14 physically active volunteers (7 males, 7 females). all subjects completed a health screening questionnaire 1 which revealed no evidence that exercise testing or training should be limited. the subjects provided informed consent and the protocol for this study was approved by the institutional review board for the protection of human subjects at the university of wisconsin-la crosse. characteristics of the subjects are presented in table i. since there was no expectation of a gender-related effect on the relationship between the session rpe and objective markers of exercise intensity, the results of all subjects were pooled into a single group for analysis. all subjects completed 7 different exercise sessions with a minimum of 2 days of rest between sessions. the first session was an incremental test to fatigue to determine maximal exercise responses for hr and peak oxygen uptake (vo2peak) (highest 30-second vo2 observed during the test). each subject completed all of their exercise sessions on either a cycle ergometer or treadmill, depending on their normal exercise habits. during the cycle ergometer protocol, the starting power output was 25 w and was increased by 25 w every 2 minutes. during the treadmill protocol, the belt velocity was set at either 5.6 or 8.1 kph (1.56 or 2.23 m.s -1 ), depending on whether the subject regularly walked or ran for exercise. the grade was 0% initially, and was increased by 2% every 2 minutes. the next 6, randomly ordered, sessions, were performed using the same mode of exercise. each was 30 minutes in duration, was of constant intensity within the trial, and varied in intensity between trials. there were 3 different intensity levels, designed to correspond to easy effort (~40 50% vo2peak), moderate effort (~60 70% vo2peak), and hard effort (~80 90%vo2peak). each subject completed each intensity session twice. during every exercise session, respiratory gas exchange was measured using open-circuit spirometry (quinton q-mc, seattle, wa) and hr was measured using radiotelemetry (polar electooy, finland). the rpe was assessed every 5 minutes throughout each exercise bout using the cr scale (table ii). thirty minutes after completing the exercise session (after having time to shower and change clothes), each subject rated the perceived intensity of the entire exercise session according to the session rpe scale (table ii), which is a modification of the conventional cr rpe scale, with verbal anchors changed to represent terms that are more relevant to exercisers fluent in american idiomatic english. in place of the usual specific verbal instructions normally used with the rpe scale, the only verbal prompting was ‘how was your workout?’ statistical comparisons were made using repeated measures analysis of variance (anova) for an intensity x trials design. statistical significance was accepted when p < 0.05. post hoc comparisons, when justified by anova, were performed using the tukey test. curve fitting and computation of correlation coefficients and/or coefficients of determination were made using a least squares technique. results the tests were completed by all subjects without complications, and all subjects completed all tests. the mean serial responses of vo2, hr and rpe are presented in fig. 1. the low-intensity exercise bout satisfied criteria for a steady state of vo2, whereas the moderate and hard exercise bouts displayed evidence of a slow component of vo2. all outcome measures differed (p < 0.05) between the 3 intensity levels. there was no significant difference between exercise intensity, measured by %vo2peak, %hrpeak, %hrreserve and session rpe during repeat trials at the same exercise intensity bout (fig. 2). the session rpe estimate of exercise intensity was also shown to be reliable using regression analysis. the relationships between day 1 and day 2 for session rpe (r 2 = 0.78, standard error of estimate (see) = 1.2), %vo2peak (r 2 = 0.96, see = 3.2), %hrpeak (r 2 = 0.93, see = 3.7), and %hrreserve (r 2 = 0.93, see = 5.7) were statistically significant, and had a small see (fig. 3). the session rpe method was compared with %vo2peak, %hrpeak and %hrreserve to gain an appreciation of the degree to which the various methods of exercise intensity were measuring the same thing. the r 2 between the session rpe and %vo2peak (r 2 = 0.76), %hrpeak (r 2 = 0.74), and %hrreserve (r 2 = 0.71) was strong, but not comparable to the r 2 amongst the various objective measures of exercise intensity (fig. 4). there was apparently a much weaker relationship between the session rpe and the objective measures of exercise intensity at the higher exercise intensities (fig. 4). table i. mean (± standard deviation) characteristics of the subjects men women age (years) 33 ± 16 23 ± 1 height (cm) 180 ± 9 165 ± 7 body mass (kg) 93 ± 17 58 ± 5 vo2peak (ml.kg -1 ) 41.5 ± 9.9 44.9 ± 5.9 hrpeak (beats.min -1 ) 170 ± 19 186 ± 22 table ii. modification of the rating of perceived exertion scale. subjects rated the entire exercise session 30 minutes after exercise in response to the verbal prompt ‘how was your workout?’ rating verbal anchor 0 rest 1 very easy 2 easy 3 moderate 4 sort of hard 5 hard 6 7 very hard 8 very, very hard 9 near maximal 10 maximal validity and reliability.indd 15 3/13/06 2:59:33 pm 16 sajsm vol 18 no. 1 2006 discussion the session rpe has already been shown to be of value in terms of evaluating exercise intensity and monitoring training in a number of situations. 6,7,10,11,13,21 the primary outcome of this study is the demonstration that the session rpe method is not only reliable during repeat challenge by the same exercise stimulus, but is well related to widely accepted objective measures of exercise training intensity. as such, we interpret the present data as supporting the validity of the session rpe method as an alternative method of monitoring exercise training. the present data are comparable with previous studies 2,3,19,20,22 which have shown rpe to be a valid and reliable measure of momentary exercise intensity. we chose not to measure blood lactate responses during either incremental or constant intensity exercise, which is the other widely accepted objective method of measuring exercise intensity. this decision was based on practical concerns rather than any particular limitation of using lactate as a monitoring tool. other studies demonstrating session rpe and lactate responses during similar exercise bouts would be of interest, and would provide a test of our early results with the session rpe method compared with blood lactate responses. 10 in this study, we used constant-load exercise bouts as the method for providing the exercise challenge. this was done because it was much more convenient to represent the exercise intensity using objective methods during steady-state exercise. previous studies from our laboratory have compared the session rpe method with hr-based measures of exercise intensity during non-steady state exercise, 8,9 with substantially similar findings to the present data. thus, we believe that the collective experience suggests that the session rpe method is a valid marker of exercise intensity under a variety of situations. other studies from our laboratory have demonstrated that the ‘drift’ in session rpe fig. 2. mean responses of %vo2peak, %hrmax, %hrreserve and session rpe during trial 1 and trial 2 of the three exercise intensity bouts. fig. 3. scatter plots of individual responses of session rpe, %vo2peak, %hrpeak and %hrreserve during trial 1 and trial 2, with all three intensities combined. fig. 1. serial responses of %vo2max, %hrmax and rpe during the course of the easy, medium and hard exercise bouts. the two trials at each intensity were combined to produce the figures. validity and reliability.indd 16 3/13/06 2:59:34 pm sajsm vol 18 no. 1 2006 17 with progressively longer performance at a fixed exercise intensity is comparable to the drift in hr during prolonged exercise. 8,9 we have not tested the session rpe under very prolonged and exhaustive exercise such as, for example, marathon running. in a situation of competitive performance (or even severe training bouts) of a very prolonged duration, the session rpe would approach maximal values, even though the objective exercise intensity would remain within a clearly submaximal zone. this problem remains to be explored in that it presents a fundamental problem in terms of monitoring exercise training. however, as this is also a limitation with hr-based methods of monitoring exercise intensity, this drift does not represent a limitation unique to the session rpe method. our underlying assumptions in studies using the session rpe method as the intensity component of monitoring training has been to use the session rpe to replace objective measures of exercise intensity within the training impulse (trimp) approach originally developed by fitz-clarke et al. 5 and morton et al. 18 and widely used by others. 6,7,12,14,15,21 the trimp approach is a very useful way of combining exercise intensity and duration into a single number representation of the stimulus for adaptation provided by any exercise bout, which has been limited by the absence of a simple method of expressing exercise intensity. during very prolonged exercise, the drift of session rpe (or of hr) acts as a multiplier of exercise duration and suggests a much larger trimp than might have been calculated using the rpe or hr early during the exercise bout as a marker of exercise intensity. this raises the more fundamental question implicit in the trimp concept related to the signal for adaptations to exercise. clearly, exercise intensity changes the milieu internal in ways that are different from exercise duration. until this signalling mechanism is elucidated, it may not be critical whether one or the other of the comparatively crude subjective methods of estimating exercise intensity is used. references 1. balady gj, chaitman b, driscoll d, et al. recommendations for cardiovascular screening, staffing and emergency policies at health/fitness facilities: a joint position statement by the american college of sports medicine and the american heart association. med sci sports exerc 1998; 30: 1009-18. 2. borg g, hassman p, langerstrom m. perceived exertion in relation to heart rate and blood lactate during arm and leg exercise. eur j appl physiol 1987; 65: 679-85. 3. borg, g, ljunggren g, ceci r. the increase of perceived exertion, aches and pains in the legs, heart rate and blood lactate during exercise on a bicycle ergometer. eur j appl physiol 1985; 54: 343-9. 4. day ml, mcguigan mr, brice ga, foster c. monitoring work intensities during resistance training using a session rpe scale. journal of strength and conditioning research 2004; 18: 353-8. 5. fitz-clarke jr, morton rh, banister ew. optimizing athletic performance by influence curves. j appl physiol 1991; 71: 1151-8. 6. foster c. monitoring training in athletes with reference to overtraining syndrome. med sci sports exerc 1997; 30: 1164-8. 7. foster c, daines e, hector l, snyder a, welsh r. athletic performance in relation to training load. wisconsin medical journal 1996; 95: 370-4. 8. foster c, florhaug j, franklin j, et al. a new approach to monitoring exercise training. journal of strength and conditioning research 2001; 15: 109-15. 9. foster c, florhaug j, hrovatin l. monitoring of athletic training. vlaams tijdschrift voor sportgeneeskunde en sportwetenshappen 1999; 80: 47-54. 10. foster c, hector l, welsh r, schrager m, green m, snyder a. effects of specific versus cross-training on running performance. eur j appl physiol 1995; 70: 367-72. 11. foster c, heimann k, esten p, brice g, porcari j. differences in perceptions of training by coaches and athletes. south african journal of sports medicine 2001; 8: 3-7. 12. foster c, hoyos j, earnest c, lucia a. regulation of energy expenditure during prolonged athletic competition. med sci sports exerc 2005; 37: 670-5. 13. impellizzeri fm, rampinni e, coutts aj, sassi a, marcora sm. use of rpebased training load in soccer. med sci sports exerc 2004; 36: 1042-7. 14. lucia a, hoyos j, carvajal a, chicharro jl. heart rate response to professional road cycling: the tour de france. int j sports med 1999; 20: 167-72. 15. lucia a, hoyos j, santally a, earnest c, chicharro jl. tour de france vs vuelta a espana: which is harder? med sci sports exerc 2003; 35: 872-8. 16. mcguigan mr, egan ad, foster c. salivary cortisol responses and perceived exertion during high intensity and low intensity bouts of resistance exercise. journal of sport science and medicine 2004; 3: 8-15. 17. mcguigan mr, foster c. a new approach to monitoring resistance training. strength and conditioning journal 2004; 26: 42-7. 18. morton rh, fitz-clarke jr, banister ew. modeling human performance in running. j appl physiol 1990; 69: 1171-7. 19. noble b, robertson r. the borg scale: development, administration, and experimental use. in: washburn r, mittelmeiner k, eds. perceived exertion. champaign, ill: human kinetics publishers, 1996: 59-92. 20. pandolf k. advances in the study and application of perceived exertion. exerc sport sci rev 1983; 11: 118-58. 21. seiler ks, kjerland go. quantifying training intensity distribution in elite endurance athletes: is there evidence for an ‘optimal’ distribution. scandinavian journal of medicine and science in sports (in press). 22. skinner j, hutsler r, bergsteinova v, buskirk e. the validity and reliability of a rating scale of perceived exertion. med sci sports 1973; 5: 94-6. 23. sweet tw, foster c, mcguigan mr, brice g. quantitation of resistance training using the session rpe method. journal of strength and conditioning research 2004; 18: 796-802. fig. 4. scatter plots of individual responses of session rpe v. %vo2peak, %hrpeak, and %hrreserve and of %vo2peak v. %hrpeak and %hrreserve and of %hrpeak v. %hrreserve. these plots demonstrate that although session rpe is significantly related to objective markers of exercise intensity, it is less well related to the objective markers of exercise intensity than the objective markers are to each other. validity and reliability.indd 17 3/13/06 2:59:34 pm 6 sajsm vol. 28 no. 1 2016 original research on-field identification and management of concussion in amateur rugby union j brown,1 phd; w viljoen,2 phd, cscs; s hendricks,1 phd; s abrahams,1 bsc (med) (hons) physiology; n burger,1 bsc (hons) sports science; s mc fie,1 bsc (hons) neuroscience; j patricios,3 mbbch, mmedsci, facsm, ffsem (uk), ffims 1 division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, cape town, south africa 2 south african rugby union, saru house, plattekloof, 163 uys krige road, cape town, south africa 3 section of sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa corresponding author: j brown (jamesbrown06@gmail.com) background: rugby is a popular team sport and due to its contact nature carries a relatively high potential for injury, including concussion. moreover, it is estimated that as much as 50% of concussions are not reported due to a variety of reasons, including not considering the injury to be sufficiently serious or not wanting to miss game time. objectives: the aim of this brief review was to investigate and summarise current best practice for on-field identification and on-field management of concussion in amateur rugby. methods: pubmed and clinicalkey were searched between september and december 2014 for articles in the five years preceding the search dates. the latest versions of the consensus statement for concussion in sports and world rugby’s concussion guidelines were also consulted. results: based on this search strategy, eight systematic reviews, one physician information article and four patient guidelines were investigated. four reviews specifically described an “action plan” for on-field evaluation and management. education of key stakeholders could reduce the number of unreported concussions. once identified or suspected, concussions should be managed according to best practice procedures, which include removing the player from play immediately and consulting a medical doctor. if a medical doctor is not immediately available on the field tools such as the boksmart on-field pocket “concussion guide”, and world rugby’s “pocket concussion recognition tool”, are freely available online. conclusion: stakeholder education (including players, parents, teachers, coaches, referees, spouses) on both the on-field identification and management of concussions could reduce under-reporting and improve the overall management of concussed rugby players. keywords: injury prevention, injury management, head injury, football s afr j sports med 2016;28(1):6-10. doi:10.17159/2078-516x/2016/v28i1a1206 the sport of rugby union (hereinafter called ‘rugby’) is one of the most popular team sports globally due to a variety of benefits that the sport offers its participants. [1] however, rugby is also associated with a high injury potential to the player.[1] of all rugby-related time-loss injuries (those necessitating missed training or match time), concussion is one of the most common injuries in senior professional rugby and is estimated to occur, on average, once in every six matches or 4.7 concussions per 1 000 player match hours.[2] the prevention of injury in general exists on a temporal continuum: from primary prevention on the one end of the continuum to tertiary prevention on the other end.[3] with regard to concussion, primary prevention refers to preventing the original injury from occurring, which is difficult in any sphere of injury prevention including sport.[3] secondary prevention refers to management of the injury: from the point of when it initially occurs through to a safe return to normal activity or match play.[3] tertiary prevention is on the other end of the prevention continuum and is specific to the management of longterm injuries and disabilities, and therefore is not relevant to this review on concussion.[3] it is estimated that only half of all concussions are reported by contact sport participants (including rugby) for a variety of reasons, such as the player does not consider the injury to be sufficiently serious, and fear of being left out of the team.[4,5] thus, unlike other common time-loss rugby injuries, such as ligament ruptures, which are physically limiting and prevent the player from participating further in the game, concussion has an ‘invisible’ nature. therefore the identification of concussion as an injury requires the active involvement of players, coaches, referees, medical support staff and parents or spouses to intervene where applicable.[4] furthermore, concussed players do not always follow the correct return-to-play guidelines (available at http://boksmart.sarugby. co.za/content/concussion) before returning to sport.[6,7] this places the injured player at risk of developing long-lasting or permanent symptoms (in extreme cases).[6,8] thus the unique nature of concussion in rugby, which has been associated with sub-optimal secondary prevention, warrants further investigation into what is considered best practice for onfield identification and management of concussion in amateur rugby union. methods the following databases were initially searched on the 18 september 2014 and rechecked before final editing on 5 december 2014: pubmed and clinicalkey. owing to this rapidly evolving field, only articles for the previous five years were considered for the pubmed search using the following search strategies: “brain concussion” (mesh term for ‘concussion’) and “post-concussion syndrome” (mesh term for symptoms post-concussive event) and “sports” (mesh heading) and the following mesh terms: “diagnosis”, “signs and symptoms” or “therapy” (mesh subheading). systematic reviews, guidelines and patient information were considered. in this regard, the latest version of the consensus statement for concussion in sport[8] and world rugby guidelines (online version as at 25 november 2015) for concussion for the general public[9] were used as a point of reference. for clinicalkey, the most recent revision of firstconsult (formerly medconsult) and patient education articles on “concussion” were consulted. any supplementary information that these articles referred to (such as scat3) were also included. mailto:jamesbrown06@gmail.com http://dx.doi.org/10.17159/2078-516x/2016/v28i1a1206 http://boksmart.sarugby.co.za/content/concussion http://boksmart.sarugby.co.za/content/concussion sajsm vol. 28 no. 1 2016 7 original research results the above-described pubmed search strategies yielded eight systematic reviews, one “firstconsult” (physician information) article,[10] and four patient guidelines. the four guidelines were from the following sources: international rugby board (irb)[9] which is now called “world rugby”, clinicalkey,[10] center for disease control and prevention (cdc),[11] and the journal of the american medical association (jama).[12] of these 13 sources, four[8,9,10,13] specifically described an “action plan” for on-field or “side-line” evaluation and management of concussion or suspected concussions in rugby games. leaving no concussion unreported the first issue with concussion management in contact sports (including rugby) is that of under-reporting by players. concussion may not be as obvious an injury to players and spectators as other common musculoskeletal injuries, such as a medial collateral ligament injury.[1,4] if a concussed player is allowed to continue playing, the risk for sustaining a further concussion with more severe or prolonged symptoms is greatly increased. in an attempt to reduce under-reporting of concussions in american football, it has been suggested that wearable technology, specifically wearable devices, could provide more objective data to make these decisions.[4] however, this is only possible in american football as the devices can be placed inside the helmets that all players are required to wear. to reduce unreported concussions, it is critical that those watching the game and especially coaches, referees, players, family members or spouses, and medical support staff (including first aiders) assume some level of responsibility for identifying suspected concussions in those players that are playing.[9] thus concussion awareness and education is critical for all stakeholders involved in rugby.[13] pre-empting concussion for improved on-field identification in south africa, the compulsory boksmart biennial rugby safety course provides concussion education, as well as pocket concussion guides for all attending coaches and referees.[14] for all other stakeholders, the boksmart (www.boksmart.com) and world rugby (www.worldrugby.org) websites provide additional education and general concussion information. another particularly useful resource is world rugby’s “pocket concussion recognition tool” available on the boksmart website (http://images.supersport.com/ pocket%20crt.pdf ). similar education in new zealand has been associated with a reduction in concussion complications.[15] however, with a historically low reporting rate, it is expected that greater awareness and education among rugby stakeholders will in fact initially increase, and not decrease concussion rates.[4,8,17] should this increase in concussion rates occur, as some reports have already found,[18] it should be considered a success for education and awareness interventions in improving secondary prevention (including better reporting), rather than a failure of primary prevention interventions in not reducing concussions. besides these education interventions, it is critical that every rugby facility is adequately prepared for handling players suspected of sustaining concussion.[8] this preparation involves, but should not be limited to: 1. the establishment of a concussion management protocol: consi­ dering how suspected players are going to be identified and by whom. 2. provisions, facilities, regulations in place to assess players on and off the field: even if this necessitates policy and rule changes. 3. a medical team who are up-to-date on the most recent concussion management protocols and literature: in charge of assessing the player and in setting up a functional clinical network, including hospitals, who can manage them appropriately. 4. the establishment of a concussion register: using the medical team, with up to date protocols, to keep a register of all concussed players, and to oversee and monitor their recovery and progress throughout the graduated return­to­play process. concussion on-field identification a concussion may be caused by direct or indirect (e.g. “whiplash”) trauma to the brain.[8,9] those potentially more susceptible to sustaining a concussion include, but are not limited to: children and adolescents; players who participate in contact sports (rugby, hockey, soccer), combat sports (boxing and martial arts), riding sports (horses, bikes, motorcycles); and players who have suffered a previous concussion.[8,9,11,13] it is imperative that concussions are properly recognised and treated as early as possible.[10] if a direct or indirect head trauma was not directly observed, any one of the following signs could indicate a potential concussion*:[9] 1. dazed, blank or vacant look 2. loss of consciousness† 3. fit/convulsion/seizure† 4. lying motionless on the ground† or slow in returning to feet 5. unsteady or any balance issues or a loss of coordination 6. confused or a lack of awareness of surrounding events 7. grabbing or clutching of the head 8. more emotional or irritable than normal. sideline concussion assessment tools the player with a suspected concussion should be removed from play and be assessed by a medically trained person who has specifically been trained in the evaluation and management of concussion.[14] the american medical society for sports medicine position statement: concussion in sport[14] states that history, balance testing and cognitive function should all be assessed, while the consensus statement on concussion in sport[8] suggests that testing of the latter (cognitive function) is most important. with any clinical test, it is important to consider the sensitivity (correctly diagnosing those that have the condition) and specificity (correctly excluding those who do not have the condition). in the light of the dangers of allowing a player with a missed concussion to continue playing, it might make more sense to rather focus on sensitivity in the context of concussion. for assessing cognitive function, the consensus statement for concussion in sport[8] recommends use of the scat3 (http://bjsm. bmj.com/content/47/5/259.full.pdf ), which should be administered by medical professionals. the scat3 includes brief versions of maddocks’ questions (e.g. “what half is it now?” or “who scored last in this match?”) and standard assessment of concussion (sac) questions (e.g. “what day is it today?” and asking the player to say the months of the year in reverse-order). * a more comprehensive list of signs and symptoms associated with concussion may be found at http://boksmart.sarugby.co.za/content/concussion. † in these instances, it is important to consider that the player may have a concomitant neck injury and should therefore only be removed by a medical professional with spinal care training.[9] http://www.boksmart.com http://www.worldrugby.org http://images.supersport.com/pocket%20crt.pdf http://images.supersport.com/pocket%20crt.pdf http://bjsm.bmj.com/content/47/5/259.full.pdf http://bjsm.bmj.com/content/47/5/259.full.pdf http://boksmart.sarugby.co.za/content/concussion 8 sajsm vol. 28 no. 1 2016 original research if no medical professional is available to perform the assessment, then the consensus statement on concussion in sport[8] and world rugby[9] suggest focussing on two of the scat3 components: 1. visible signs and symptoms 2. maddocks’ questions. these two assessments are packaged as a freely available, pocket-sized resource (http://bjsm.bmj.com/content/47/5/267. full.pdf ) called the pocket concussion recognition tool (crt). the boksmart on-field pocket concussion guide also includes these two components (http://images.supersport.com/content/ concussion%20guide%20v6%202015%20lr.pdf ). despite the consensus statement on concussion in sport advocating them as “practical and effective”, it is important to note that the sensitivity and specificity of the scat3 and pocket concussion recognition tools (crt) are yet to be assessed (table 1).[13] nonetheless, certain individual components of the scat3 and pocket crt, specifically the sac and 17-point symptom scores assessment, have been associated with the highest sensitivities recorded for concussion screening tools (94 and 89%, respectively).[13] table 1. sensitivity (ability to detect concussion) of various tools suggested for concussion on-field identification (modified from[13]) test (administration time) sensitivity % (diagnosed concussions) symptom score (2-3 mins): 9-item 68 17-item 89 maddocks’ questions (<1 min) 32-75 sac (5 mins) 80-94 bess (5 mins) 34 modified bess (2-3 mins) not known sac + bess (10 mins) not known nfl sideline concussion assessment tool not known pocket concussion recognition tool (5 mins) not known scat 3 (8-10 mins) not known boksmart pocket concussion guide not known king-devick (2 mins) not known bess – balance error scoring system sac – standard assessment of concussion nfl – national football league scat – sport concussion assessment tool the proclaimed “validity” of the maddocks’ questions should be interpreted with caution. there is only one study that has assessed the sensitivity of maddocks’ questions – this was performed in 1995 in 28  professional australian rules football players (table 1).[19] with 14 subjects in each group, it is unlikely that this study has the statistical power to ascertain whether maddocks’ questions are valid or not. additionally, the fact that the lead author was testing the diagnosis tool that he had also developed, could constitute a conflict of interest. importantly, the consensus statement on concussion in sport stipulates that none of these brief cognitive tests replace a comprehensive neuropsychological test by a trained medical person, but they offer a screening tool for rapid assessment of a player suspected of having a concussion.[8] in terms of assessing balance, the balance error scoring system (bess) is recommended by the american medical society for sports medicine position statement: concussion in sport, although it appears to be more useful in assessing those who are not concussed than those who are concussed.[13] however, this test does not appear to be particularly sensitive as empirical evidence suggests this assessment misses about two-thirds (66%) of concussions (table 1).[13] recently, the king-devick test, a rapid eye movement test that was designed to detect oculomotor inefficiencies, has shown promising results in detecting concussions in mixed-martial arts, boxers and rugby union and league players.[20,21] however, as the authors who have done most of the testing of the king-devick test in rugby state: “… there have been no longitudinal studies to assess the reliability, validity or generalizability of the king­devick test, nor has it been tested across various age groups.”[21] therefore, this test has not yet been endorsed by the consensus statement for concussion in sport[8] and world rugby.[9] despite the lack of empirical evidence supporting the sensitivity of the discussed concussion assessments for both medical (scat3, and the tests of which it is comprised) and for non-medical people (pocket crt), this should not deter their prescribed use. these tools are all endorsed by both the consensus statement for concussion in sport[8] and world rugby[9] and therefore constitute current best-practice in the game. however, it should be noted that these recommendations might change over time: for example, with more research, the king-devick test might be included in future consensus or guideline documents. on-field concussion management in contrast to the equivocal literature on sideline concussion assessment tools, there is substantial consensus on the management once a player is suspected of having sustained a concussion. once a concussion is suspected (through either of the recommended methods), a medical professional trained in concussion management should immediately implement the five step on-field management procedure outlined in figure 1. this diagram presents a summary of the four resources identified for this particular research question.[8,9,11,13] step 1. potentially concussed player is removed from play immediately. step 2. evaluation by licensed healthcare provider (medical doctor) on site. special attention given to potential concomitant neck/cervical spine injury. if no appropriately qualified healthcare provider available on site, the player should be urgently referred to one. step 3. assessment of the concussive injury by licensed healthcare provider (medical doctor) using the scat3 or other sideline evaluation tools that include orientation questions (e.g. "where are we?"), and balance assessment step 4. after a clear diagnosis is made or there is a strong suspicion of concussion, the player should be monitored for any mental or physical deterioration (severe persistent headache, repeated vomiting, confusion) step 5. a player with a diagnosed concussion or with a strong suspicion of concussion should never be allowed to return to play (rtp) or train on the same day of the injury fig. 1. five step course of action for managing a player with a confirmed concussion or suspected concussion[8,9,11,13] http://bjsm.bmj.com/content/47/5/267.full.pdf http://bjsm.bmj.com/content/47/5/267.full.pdf http://images.supersport.com/content/concussion%20guide%20v6%202015%20lr.pdf http://images.supersport.com/content/concussion%20guide%20v6%202015%20lr.pdf sajsm vol. 28 no. 1 2016 9 original research step 1 the world rugby guidelines for the general public[9] and the american medical society for sports medicine (amssm) position statement[13] specifically state that the concussed or potentially concussed player should immediately be removed from play and then be evaluated by a healthcare provider. the wording of the consensus statement for concussion in sport[8] was more ambiguous on this point and the clinicalkey patient guidelines[11] did not have a temporal reference for the potentially concussive event. therefore as two of the four sources explicitly stated that the player should be immediately removed from play, this has been included in step 1. step 2 only the amssm position statement[13] specifically stated that the licensed healthcare provider (medical doctor) should be trained in the evaluation and management of concussion. while this is probably an important addition, it was not mentioned by any of the other three sources. similarly, only the consensus statement[8] made mention of the fact that the healthcare provider’s evaluation should be made “in a timely manner”. however, both the consensus statement[8] and world rugby’s guidelines[9] made specific reference to the careful consideration of neck/cervical spinal injuries in concussed or potentially concussed players. step 3 the consensus statement for concussion in sport[8] and world rugby recommend that the scat3 (medical professional) or pocket crt (non-medical person) are used to assess the concussion. although the clinimetric properties have been debated in this article (sideline concussion assessment tools), these tools represent current bestpractice and should therefore be used as prescribed. step 4 all resources except for the clinicalkey patient guideline[11] suggested that the concussed player should be monitored after the injury. the amount of time after the injury was different for each source: the world rugby guidelines[9] state a minimum of 24-hours, the consensus statement states “in the initial few hours after the injury” and the amssm position statement[13] does not specify a time. the specific signs and symptoms to be aware of differ depending on the resource consulted. step 5 all resources, except for the clinicalkey patient guideline,[11] explicitly state that a player with a diagnosed concussion is not able to return to play or train on the same day. the clinicalkey patient guideline[11] states that return-to-play was a controversial subject in general and that it should be guided by the healthcare provider managing the injury. discussion the main finding from this review was that the identification and reporting of the initial concussion is more of a challenge and topic for scientific debate than the management of the injury per se.[4,5,17] while alternate options have been suggested for american football, the consensus for improving this underreporting in rugby appears to be through education interventions and raising awareness in medical professionals and stakeholders (coaches, referees, players, teachers, parents and spouses). similarly, it is important to try and reduce incorrect or suboptimal behaviours in stakeholders who are already armed with the correct information.[4,5,17] the boksmart compulsory biennial rugby safety course for coaches and referees is an example of an intervention that aims to educate coaches and referees on all aspects of concussion, including identification.[14] additionally, the boksmart website (www.boksmart.com) provides freely available educational information, as well as useful tools for identifying those players suspected of being concussed. world rugby has similar resources: http://playerwelfare.worldrugby.org/concussion. while some authors debate the sensitivity of sideline concussion assessment tools in diagnosing concussions, the scat3 (for medical professionals) and pocket crt (for non-medical professionals) are recommended by both the consensus statement for concussion in sport[8] and world rugby.[9] in contrast to the strategies to improve concussion reporting, there was substantial consensus on the management of a concussion once identified. the only major discrepancies are in the amssm position statement[13] that specifically states that the “licensed healthcare provider (medical doctor)” who assesses the potentially concussed player must be trained in concussion management (step  1). while this may be a valid point, it is not mentioned in the consensus statement for concussions in sport[8] or world rugby’s guidelines for concussion for the general public.[9] however, this is probably due to the fact that world rugby’s guidelines were based on the consensus statement.[9] nonetheless, as the clinicalkey patient guidelines did not provide any information on these points of disagreement and because this review was ultimately investigated with rugby union in mind, the findings of the amssm position statement were weighted with less importance.[13] in conclusion, the on-field identification and management of concussion needs to be improved in amateur rugby. reporting can be improved through greater education and awareness in stakeholders, and in the use of sideline concussion assessment tools. for sideline concussion assessments, the scat3 and pocket crt’s should be used by medical and non-medical professionals respectively, where possible. once a concussion has been identified in amateur rugby, the sporting venue where the injury takes place needs to have measures in place to optimally manage the injured player, as described in this review. conflict of interest: none. acknowledgements: james brown would like to thank the boksmart program and chris burger petro jackson players’ fund who provided his post-doctoral fellowship funding. this author would also like to thank mr clint readhead for his advice on specific aspects of this article. references 1. williams s, trewartha g, kemp s, et al. a meta-analysis of injuries in senior men’s professional rugby union. sports med 2013 oct;43(10):1043-1055. [http://dx.doi. org/10.1007/s40279-013-0078-1] 2. gardner aj, iverson gl, williams wh, et al. a systematic review and meta-analysis of concussion in rugby union. sports med 2014 dec;44(12):1717-1731. [http:// dx.doi.org/10.1007/s40279-014-0233-3] 3. pless ib, hagel be. injury prevention: a glossary of terms. j epidemiol community health 2005 mar;59(3):182-185. [http://dx.doi.org/10.1136/jech.2003.017715] http://www.boksmart.com http://playerwelfare.worldrugby.org/concussion http://dx.doi.org/10.1007/s40279-013-0078-1 http://dx.doi.org/10.1007/s40279-013-0078-1 http://dx.doi.org/10.1007/s40279-014-0233-3 http://dx.doi.org/10.1007/s40279-014-0233-3 http://dx.doi.org/10.1136/jech.2003.017715 10 sajsm vol. 28 no. 1 2016 original research 4. greenwald rm, chu jj, beckwith jg, et al. a proposed method to reduce underreporting of brain injury in sports. clin j sport med 2012 mar;22(2):83-85. [http://dx.doi.org/10.1097/jsm.0b013e31824cc5d3] 5. fraas mr, coughlan gf, hart ec, et al. physical therapy in sport. physical therapy in sport. elsevier ltd;2013 sep 11;:1-7. [http://dx.doi.org/10.1016/j.ptsp.2013.08.002] 6. doolan aw, day dd, maerlender ac, et al. a review of return to play issues and sports-related concussion. ann biomed eng 2012 jan;40(1):106-113. [http://dx.doi. org/10.1007/s10439-011-0413-3] 7. brown jc, viljoen w, lambert mi, et al. the economic burden of time-loss injuries to youth players participating in week-long rugby union tournaments. j sci med sport 2014 aug 16;18(4):1-6. [http://dx.doi.org/10.1016/j.jsams.2014.06.015] 8. mccrory p, meeuwisse wh, aubry m, et al. consensus statement on concussion in sport: the 4th international conference on concussion in sport held in zurich, november 2012. br j sports med 2013 mar 11;47(5):250-258. [http://dx.doi. org/10.1136/bjsports-2013-092313] 9. world rugby. concussion management for the general public. [www.playerwelfare. worldrugby.org/concussion] accessed october, 2014. pp. 1-7. 10. clinical key. ‘concussion – first consult’. [https://www.clinicalkey.com/#!/content/ medical_topic/21-s2.0-2001133] accessed october, 2014. 11. centers for disease control and prevention. heads up, concussion in youth sports. [http://www.cdc.gov/concussion/headsup/index.html] 2013. accessed oct ober, 2014. pp. 1-4. 12. pluta rm. concussion. golub rm (ed.). journal of american medical association. [http://www.jama.jamanetwork.com/article.aspx?articleid=1104031] accessed october, 2014. 13. harmon kg, drezner j, gammons m, et al. american medical society for sports medicine position statement: concussion in sport. br j sports med 2013 jan;47(1):15-26. [http://dx.doi.org/10.1136/bjsports-2012-091941] 14. viljoen w, patricios j. boksmart – implementing a national rugby safety programme. br j sports med 2012 aug;46(10):692-693. [http://dx.doi.org/10.1136/ bjsports-2012-091278] 15. gianotti s, hume pa. concussion sideline management intervention for rugby union leads to reduced concussion claims. neurorehabilitation 2007;22(3):181-189. pmid: 17917168. 16. finch c, clapperton aj, mccrory p. increasing incidence of hospitalisation for sportrelated concussion in victoria, australia. med j aust 2013 may 6;198(8):427-430. [http://dx.doi.org/10.5694/mja12.11217] 17. marshall sw, spencer rj. concussion in rugby: the hidden epidemic. j athl train 2001;36(3):334-338. pmid: 12937506. 18. cross m. england professional rugby injury surveillance project 2013-2014. kemp s, brooks j, eds. rugby football union 2015 jan;:1-19. 19. maddocks dl, dicker gd, saling mm. the assessment of orientation following concussion in athletes. clin j sport med 1995 jan 1;5(1):32-35. [http://dx.doi. org/10.1097/00042752-199501000-00006] pmid: 7614078. 20. galetta km, barrett j, allen m, et al. the king-devick test as a determinant of head trauma and concussion in boxers and mma fighters. neurology 2011 apr 26;76(17):1456-1462. [http://dx.doi.org/10.1212/wnl.0b013e31821184c9] 21. king d, gissane c, hume pa, et al. the king-devick test was useful in management of concussion in amateur rugby union and rugby league in new zealand. j  neurolog sci 2015 apr 15;351(1-2):58-64. [http://dx.doi.org/10.1016/j. jns.2015.02.035] http://dx.doi.org/10.1097/jsm.0b013e31824cc5d3 http://dx.doi.org/10.1016/j.ptsp.2013.08.002 http://dx.doi.org/10.1007/s10439-011-0413-3 http://dx.doi.org/10.1007/s10439-011-0413-3 http://dx.doi.org/10.1016/j.jsams.2014.06.015 http://dx.doi.org/10.1136/bjsports-2013-092313 http://dx.doi.org/10.1136/bjsports-2013-092313 https://www.clinicalkey.com/#!/content/medical_topic/21-s2.0-2001133 https://www.clinicalkey.com/#!/content/medical_topic/21-s2.0-2001133 http://www.cdc.gov/concussion/headsup/index.html http://www.jama.jamanetwork.com/article.aspx?articleid=1104031 http://dx.doi.org/10.1136/bjsports-2012-091941 http://dx.doi.org/10.1136/bjsports-2012-091278 http://dx.doi.org/10.1136/bjsports-2012-091278 http://dx.doi.org/10.5694/mja12.11217 http://dx.doi.org/10.1097/00042752-199501000-00006 http://dx.doi.org/10.1097/00042752-199501000-00006 http://dx.doi.org/10.1212/wnl.0b013e31821184c9 http://dx.doi.org/10.1016/j.jns.2015.02.035 http://dx.doi.org/10.1016/j.jns.2015.02.035 _goback original research 46 sajsm vol. 28 no. 2 2016 mindfulness and mental toughness among provincial adolescent female hockey players sp walker, phd unit for professional training and services in the behavioural sciences (unibs), faculty of the humanities, university of the free state, bloemfontein, south africa corresponding author: sp walker (walkersp@ufs.ac.za) mental toughness has come to be widely viewed as an important prerequisite for sustained athletic achievement.[1-2] however, from a theoretical perspective, there is disagreement on the precise definition of mental toughness, while the effective and accurate operationalisation of mental toughness remains challenging at an empirical level.[3] nevertheless, the general consensus appears to be that mentally tough athletes are resilient, goal-focused and confident in their abilities, as well as proficient at regulating their emotions and behaviour. [1-3] a body of research exploring various methods and techniques for enhancing mental toughness has emerged over the past decade. however, relatively little attention has been focussed on identifying the behavioural, cognitive and emotional mechanisms that bolster mental toughness.[4] there is thus both a theoretical and practical need to explore the psychological basis of mental toughness from within existing, evidence-based psychotherapeutic, counselling and coaching paradigms. relatively few studies have evaluated the efficacy of psychological interventions aimed specifically at the development of mental toughness among athletes. the existing studies have focussed primarily on cognitivebehavioural interventions, which have generally demonstrated post-intervention improvements in mental toughness.[5-6] however, cognitive-behavioural interventions aimed specifically at developing mental toughness do not appear to be superior to general mental skills development interventions when it comes to developing or increasing mental toughness.[6] recently, questions have been raised regarding evidence for the efficacy of mental skills interventions aimed at improving athletic performance and thus by implication, the efficacy of interventions purporting to develop or improve mental toughness.[7] based on the robust outcome data on mindfulness-based interventions in the field of clinical psychology, it has been suggested that a greater focus on mindfulness and mindfulness-based intervention might be indicated within the areas of sport and performance psychology in general, and with regard to mental toughness specifically. [7-8] mindfulness may be defined as the non-judgemental awareness of internal and external experiences as they occur in the present moment.[9] mindfulness-based approaches to performance enhancement advocate viewing emotions and cognitions as internal events, rather than objective or factual manifestations of reality that need to be changed or controlled to facilitate peak performance.[8;10] the core assumption of mindfulness-based approaches to performance enhancement is that once an individual is free of the need to control his or her thoughts and emotions they are in a position to optimally focus attentional resources outward on the execution of skills. this conceptualisation differs from that advocated by cognitive-behavioural interventions and traditional mental skills training, which promote the monitoring, evaluation and restructuring of cognition so as to enhance athletic performance by optimising the regulation of emotion and behaviour. [7] to date, no studies have been published on the specific role of mindfulness in mental toughness. however, a number of researchers have investigated the influence of mindfulness on the wellbeing of athletes and, more generally, athletic introduction: mental toughness is highly valued within competitive sport. however, scant attention has been paid to the psychological processes that underpin mental toughness. objectives: to explore the relationship between mindfulness and mental toughness among provincial adolescent female hockey players. methods: provincial adolescent female hockey players (n=484) completed measures of mindfulness and mental toughness. correlation coefficients were calculated with respect to mindfulness and mental toughness. a one-way between-groups analysis of variance (anova) was conducted to determine whether athletes assigned to four levels of mindfulness (high, moderate, medium and low) differed significantly with regard to mental toughness. results: mindfulness exhibited significant positive correlations with confidence, constancy and control, as well as with total mental toughness. the results of the anova and the relevant post hoc analyses indicated that athletes in the high mindfulness group reported significantly higher levels of control and general mental toughness than those in the other three groups. the high mindfulness participants also reported significantly higher levels of constancy than those in the medium and low mindfulness groups. conclusion: mindfulness was positively correlated with all aspects of mental toughness investigated in this study. in addition, individuals with high levels of mindfulness reported higher control, constancy and general mental toughness than those with lower levels of mindfulness. based on the current findings, the role of mindfulness in the development and maintenance of mental toughness among adolescent athletes warrants further investigation. keywords: mental toughness, mindfulness, athlete, adolescent, female s afr j sports med 2016;28(2):46-50. doi: 10.17159/2078-516x/2016/v28i2a1110 http://dx.doi.org/10.17159/2078-516x/2016/v28i2a1110 original research sajsm vol. 28 no. 2 2016 47 performance. mindfulness-based interventions have been shown to be associated with improved sporting achievement, increased self-confidence and the facilitation of performancepromoting states, such as flow. [8,10] the available evidence would seem to suggest that mindfulness is positively associated with a number of desirable sporting outcomes. however, the role of mindfulness in mental toughness remains unexamined. the aim of the current study was thus to explore the potential association of mindfulness with mental toughness among provincial adolescent female hockey players. methods participants ethical clearance to conduct the study was obtained from the relevant institutional body. the south african hockey association granted permission for data to be collected at annual female under-16 and under-19 interprovincial tournaments. informed consent was obtained from all participants, as well as from the guardians of all minors, prior to the administration of the questionnaires. data was gathered between matches or in the evenings under the supervision of the researcher or research assistant. a total of 484 adolescent female hockey players participated in the study. the mean age of the sample was 16.2 years (sd ± 1.2). participants reported playing hockey competitively for an average of 8.4 years (sd ± 2.5). on average, participants had competed in 2.4 interprovincial tournaments (sd ± 1.4), with 6% having previously been selected for national teams. measures the sport mental toughness questionnaire (smtq) was used to measure mental toughness. [11] the smtq is a 14 item self-report questionnaire that yields a total mental toughness score, as well as scores on three subscales: confidence; constancy; and control. responses to each item are indicated along a four-point likert-type scale anchored by “not at all true” and “very true”. higher scores are indicative of higher levels of mental toughness. acceptable construct validity and internal consistency have been reported for the smtq. [11] the child and adolescent mindfulness measure (camm) was utilised as a measure of mindfulness. [12] the camm is a ten-item self-report inventory with response options ranging from ’never true’ to ’always true’ along a five-point likerttype scale. the camm yields a unitary mindfulness score, with higher scores indicating higher levels of mindfulness. the camm has demonstrated acceptable psychometric properties. [12] the smtq and camm were translated into afrikaans. participants thus had the option of completing the questionnaires in either afrikaans or english. analysis pearson’s correlation coefficients were calculated for the camm total score, smtq total score, smtq confidence, smtq constancy and smtq control. based on the distribution of the camm scores in the sample, participants were divided into four levels of mindfulness (low, medium, moderate and high). a one-way between-groups analysis of variance (anova) was conducted to determine whether individuals in the four levels of mindfulness differed significantly with regard to their smtq subscale and total mean scores. scheffé’s post hoc test was used to determine the nature and direction of the significant differences determined by the anova. results the correlations between the smtq and the camm are presented in table 1. mean scores, sds and internal consistency coefficients for each scale are also reported. it is apparent from table 1 that all measures, with the exception of smtq constancy scale (α=0.55), demonstrated acceptable levels of internal consistency and may thus be included in further analyses.[13] given that the smtq constancy scale represents a theoretically valid mt construct, it was decided to include this scale in further analyses despite its poor internal consistency. the correlation coefficients in table 1 suggest that mindfulness is positively and significantly correlated with all three smtq scales (confidence (cnf): p≤0.05; constancy (cst): p≤0.01; control (ctl): p≤0.01), as well as with the smtq total score (p≤0.01). given that there was a significant positive relationship between mindfulness and mental toughness, it was decided to investigate whether individuals reporting different levels of mindfulness differ significantly with regard to their level of mental toughness. consequently, four levels (high, moderate, medium and low) of the independent variable (mindfulness) were created by dividing the sample into quarters based on the distribution of their camm scores (low: camm≤18; n=129; medium: camm 19 22; n=118; moderate: camm 23 – 26; n=121; high camm≥27; n=118). a one-way between-groups analysis of variance (anova) was conducted to investigate differences between the four levels of the independent variable (mindfulness) with regard to mental toughness. four dependent variables were included in the analysis: total mental toughness (smtq tot); control (smtq cnt); constancy (smtq cst) and confidence (smtq cnf). preliminary assumption testing was conducted to check for normality, linearity, univariate and multivariate outliers, homogeneity of variance-covariance matrices and multicollinearity. no violations were detected. a statistically significant difference was apparent between the levels of mindfulness on the combined dependent variables (f(9;1168)=9.424; p=0.0001; wilks’λ=0.843; partial η2=0.055). follow-up univariate anovas were conducted to ascertain the specific smtq scales with regard to which the four mindfulness groups differed (table 2). table 2 indicates that significant differences were apparent for level of mindfulness with regard to constancy (smtq cst; p=0.0001), control (smtq ctl; p=0.0001) and total mental toughness (smtq tot; p=0.0001). the levels of constancy, control and total mt reported by the individuals in the four mindfulness groups thus differed to a statistically significant degree. however, when the relevant f-values are calculated (constancy: f=0.05; control: f=0.15; total mental toughness: f=0.1) it is apparent that while statistically significant, all three of these results reflect small to medium effect sizes and are thus of limited practical importance.[14] original research 48 sajsm vol. 28 no. 2 2016 post hoc comparisons using the scheffé test indicated that the high mindfulness group reported a significantly higher mean smtq total score (44.5; sd±4.7) than the participants in the moderate (42.0; sd±5.4; p=0.003), medium (41.3; sd±5.3; p=0.000) and low (40.0 sd±5.3; p=0.000) mindfulness groups. in addition, the high mindfulness group reported a significantly higher smtq control score (12.1; sd±2.0) than the participants in the moderate (11.1; sd±2.2; p=0.003), medium (10.5; sd±2.4; p=0.000) and low (9.6 sd±2.2; p=0.000) mindfulness groups. however, the mean smtq control score (9.6, sd±2.2) reported by the low mindfulness group was only significantly lower than that reported by the moderate (11.1; sd±2.2; p=0.000) and high (12.1; sd±2.0; p=0.000) mindfulness groups. finally, the individuals in the high mindfulness group also reported higher mean smtq constancy scores (14.2; sd±1.6) than those in the medium (13.4; sd±1.9; p=0.009) and low (13.0; sd±1.9; p=0.000) mindfulness groups. discussion the results of the current study indicate that mindfulness is significantly and positively correlated with not only global mental toughness, but also with confidence, constancy and control. this suggests that as mindfulness increases among provincial female hockey players, so does their general level of mental toughness. in addition, increased mental toughness appears to be accompanied by more confidence in the player’s ability to overcome challenges, improved adherence to a training regimen and more efficient self-regulation of competition-related behaviours and emotions.[1-2] these findings are consistent with the existing literature with regard to mindfulness being positively associated with various cognitive processes and affective states necessary for success in athletic competition.[7-8,10] mindfulness may thus enable hockey players to respond more effectively to the behavioural demands of their competitive (e.g. tactical awareness and skills execution) and training (e.g. effortful training and skills acquisition) environments. more specifically, mindful athletes may be less inclined to becoming embroiled in unproductive attempts at cognitive and behavioural self-regulation.[9-10] there appears to be value in implementing mindfulness interventions that have been shown to be effective in other sports within provincial adolescent hockey.[8,10,15] the analyses of variance indicate that different levels of mindfulness are associated with differing levels of mental toughness across provincial female adolescent hockey players. more specifically, those participants classified as having high levels of mindfulness reported greater global mental toughness, as well as superior control compared to participants classified within the moderate, medium and low mindfulness categories. this suggests that adolescent female hockey players with high levels of mindfulness are significantly more capable of effectively dealing with the training and competition demands at the provincial level than players with lower levels of mindfulness. furthermore, these players appear to be significantly more proficient at regulating their emotional and behavioural responses within the competitive environment than players with lower levels of mindfulness. it would thus seem that greater openness to experience, elevated levels of self-acceptance and superior efficiency at maintaining a present moment focus, facilitate a more effective approach to coping with challenges and dealing with competitive pressure. the current findings are in line with existing research highlighting mindfulness as an important component of sport-specific resilience. particularly the ability to employ behavioural and emotional responses in service of one’s sporting goals, rather than allocating these psychological resources in a manner that is inconsistent with one’s performance objectives.[7-8] the association between mindfulness and control among provincial adolescent female hockey players must, however, be interpreted more circumspectly than that between mindfulness and global mental toughness. the current study indicates that the low mindfulness table 1. pearson correlation coefficients, means, sds and internal consistencies for smtq and camm (n = 484) smtq cnf smtq cst smtq ctl smtq camm mean (±sd) α camm 0.12† 0.23* 0.39* 0.31* _ 22.2 (±6.1) 0.74 smtq tot 0.79* 0.70* 0.71* _ 41.9 (±5.4) 0.76 smtq ctl 0.25* 0.35* _ 10.8 (±2.4) 0.66 smtq cst 0.36* _ 13.5 (±1.9) 0.55 smtq cnf _ 17.6(±3.0) 0.72 *p≤0.01; †p≤0.05 camm = child and adolescent mindfulness measure; smtq tot = sport mental toughness questionnaire total score; smtq cnf = spor t mental toughness questionnaire confidence scale; smtq cst = sport mental toughness questionnaire constancy scale; smtq ctl = sport mental toughness questionnaire control scale; α = cronbach alpha coefficients table 2. means, sds and f-values for the one-way analysis of variance (anova) for the four levels of mindfulness smtq scale high camm moderate camm medium camm low camm f-value p-value mean (±sd) mean (±sd) mean (±sd) mean (±sd) confidence 18.2 (±3.0) 17.4 (±3.1) 17.4 (±2.8) 17.3 (±3.2) 2.392 0.068 constancy 14.2 (±1.6) 13.5 (±1.9) 13.4 (±1.9) 13.0 (±1.9) 8.255* 0.0001 control 12.1 (±2.0) 11.1 (±2.2) 10.5 (±2.4) 9.6 (±2.2) 27.296* 0.0001 total 44.5 (±4.7) 42.0 (±5.4) 41.3 (±5.3) 40.0 (±5.3) 16.768* 0.0001 *p≤0.01 smtq = sport mental toughness questionnaire; camm = child and adolescent mindfulness measure original research sajsm vol. 28 no. 2 2016 49 participants reported significantly lower global mental toughness only in comparison to the moderate and high mindfulness groups. similarly, the hockey players in the high mindfulness group reported significantly higher levels of constancy only with respect to participants categorised as having low or medium levels of mindfulness. these findings suggest that the association between mindfulness and certain aspects of mindfulness (constancy and control) are more pronounced, and thus more relevant, at the distributional extremes of the current sample. this is, in all probability, as a result of the statistically pragmatic yet normatively arbitrary manner in which the sample was divided into four levels of mindfulness. it also underlines the practical value of viewing levels of mindfulness in athlete populations as continuous and fluid, rather than discrete. furthermore, the small to medium effect sizes reported for the follow-up univariate anovas indicate that the differences between the various levels of mindfulness are of limited practical value. consequently, the differences in mental toughness between the mindfulness groups should be viewed as indicative of statistical trends rather than definitive real-world differences in mental toughness. [14] there were no significant differences between the four mindfulness groups with regard to confidence. the literature does not offer an obvious explanation for this finding. however, it could be hypothesised that within this age cohort player confidence is still largely dependent upon external feedback regarding skill and competitive ability.[16] consequently, as all the participants were provincial hockey players, it could be reasoned that little statistically significant variability should be expected with regard to their estimations of their abilities to successfully deal with the competitive challenges they face. a more theoretically consistent explanation might be that mindful athletes incline more toward a self-referenced basis for confidence, while less mindful athletes place greater emphasis on comparing their abilities to the situations they may face or to their peers.[7] if this is the case, traditional measures of mental toughness and confidence may be inconsistent with a more mindfully-based conceptualisation of sport-specific confidence. a more pragmatic view might be that confidence is a prized and much emphasised attribute at all levels of performance. as such, measures of confidence could be vulnerable to positive response bias, resulting in the distribution of scores within the sample being excessively skewed in the direction of high sporting confidence. study limitations the study is not without limitations. first, a cross-sectional correlational design was used, thus no conclusions can be drawn regarding possible causal relationships between mindfulness and mental toughness. future studies might use more sophisticated modelling methods to investigate possible pathways of causality between mindfulness and mental toughness. intervention studies could then be embarked upon to determine the effect of mindfulness-based sport performance interventions on mental toughness. second, a very homogenous sample was used in this study with obvious implications regarding the generalisability of the findings beyond the current sample. consideration should be given to replicating the study in individual sports and among male athletes, as well as in mixed gender samples. third, the current study only explored the relationship between mindfulness and mental toughness. it is also necessary to determine the relationship between mental toughness and other constructs within the increasing number of mindfulness-oriented performance interventions, such as acceptance, cognitive defusion and values clarification.[7] finally, the camm is a generic measure of mindfulness. consequently, it might be useful to adapt the camm or otherwise develop a sport-specific measure of mindfulness for use in studies of this nature. conclusion while exploratory in nature, the current study provides evidence of a positive association between mindfulness and mental toughness among provincial adolescent female hockey players. it appears that players reporting higher levels of mindfulness demonstrate greater global mental toughness, are more consistent in their approach to their sport and are more proficient in regulating their behaviour and emotions within the competitive environment. notwithstanding the limitations of the study and the need for further research, the promotion of mindfulness could be expected to have a positive effect on the mental toughness of this specific sporting population. acknowledgements: the author would like to thank mrs. hanli van der merwe for her assistance with data collection and prof karel esterhuyse for his comments on an earlier draft of this paper. references 1. jones g, hanton, s, connaughton d. a framework of mental toughness in the world’s best performers. sport psychol 2007;21(2):243-264. doi:10.1123/tsp.21.2.243. 2. sheard m. mental toughness: the mindset behind sporting achievement. new york. routledge, 2010. 3. gucciardi df, hanton s, gordon s, et al. the concept of mental toughness: tests of dimensionality, nomological network, and traitness. j pers 2015; 83(1):26-44. [http://dx.doi.org/10.1111/jopy.12079] 4. connaughton d, thelwell r, hanton s. mental toughness development: issues, practical implications and future direction. in: gucciardi df, gordon s. mental toughness in sport: developments in theory and research. new york: routledge, 2011. 5. parkes jf, mallet cj. developing mental toughness: attributional style retraining in rugby. sport psychol 2011; 25(3):269-287. doi: 10.1122/tsp.25.3.269 6. gucciardi df, gordon s, dimmock ja. evaluation of a mental toughness training program for youth-aged australian footballers: i. a quantitative analysis. j appl sport psychol 2009; 21(3):307-323. [http://dx.doi.org/10.1080/1041320093026066] 7. gardner fl, moore ze. the psychology of enhancing human performance: the mindfulness-acceptance-commitment (mac) approach. new york: springer, 2007. 8. sappington r, longshore k. systematically reviewing the efficacy of mindfulness-based interventions for enhanced athletic performance. j clin sport psychol 2015;9(3):232-262. [http://dx.doi.org/10.1123/jcsp.2014-0017] 9. baer ra. mindfulness training as a clinical intervention: a conceptual and empirical review. clin psychol sci prac 2003;10(2):125-143. [http://dx.doi.org/10.1093/clipsy. bpg016] original research 50 sajsm vol. 28 no. 2 2016 10. pineau tr, glass c, kaufman ka, et al. selfand team-efficacy beliefs of rowers and their relation to mindfulness and flow. j clin sport psychol 2014;8(2):142158. [http://dx.doi.org/10.1123/jcsp.2014-0019] 11. sheard m, golby j, van wersch a. progress toward construct validation of the sport mental toughness questionnaire (smtq). euro j psychol assess 2009;25(3):186-193. [http://dx.doi.org/10.1027/1015-5759.25.3.186] 12. greco la, baer ra, smith gt. assessing mindfulness in children and adolescents: development and validation of the child and adolescent mindfulness measure (camm). psychol assess 2011;23(3):606-614. [http://dx.doi.org/10.1037/a0022819] 13. foster jj, parker i. carrying out investigations in psychology: methods and statistics. leicester: the british psychological society, 1999. 14. cohen j. statistical power analysis for the behavioral sciences. 2nd ed. new york. academic press, 1988. 15. thompson rw, kaufman ka, de petrillo la, et al. one year followup of mindful sport performance enhancement (mspe) with archers, golfers and runners. j clin sport psychol 2011;5(2):99-116. doi: 10.1123/jesp.5.2.99 16. magyar tm, feltz dl. the influence of dispositional and situational tendencies on adolescent girls’ sport confidence sources. psychol sport exerc 2003:4(2):175-190. [http://dx.doi.org/10.1016/s14690292(01)00037-1] sajsm 534.indd original research sajsm vol. 26 no. 3 2014 77 background. the association between self-perceived and actual physical activity, with particular reference to physical activity guidelines, may be an important factor in determining the extent of uptake of and compliance with physical activity. objectives. to examine the association between self-perceived and actual physical activity in relation to physical activity guidelines, with reference to volume, intensity and duration of steps/day, and to establish the level of agreement between pedometer-measured and selfreported ambulatory physical activity, in relation to current guidelines. methods. a convenience sample of adults (n=312; mean (standard deviation) age 37 (9) years), wore a pedometer (minimum 3 consecutive days) and completed a questionnaire that included information on physical activity patterns. analyses of covariance, adjusted for age and gender, compared volumeand intensity-based steps according to meeting/not meeting guidelines (self-reported). the extent of agreement between self-reported and pedometer-measured physical activity was also determined. results. average (sd) steps/day were 6 574 (3 541). of a total of 312 participants’ self-reported data, those meeting guidelines (n=63) accumulated significantly more steps/day than those not meeting guidelines (8 753 (4 251) v. 6 022 (3 114) total steps/day and 1 772 (2 020) v. 421 (1 140) aerobic steps/day, respectively; p<0.0001). more than half of the group who self-reported meeting the guidelines did not meet guidelines as per pedometer data. conclusion. the use of pedometers as an alternative and/or adjunct to self-reported measures is an area for consideration. steps/day recommendations that consider intensity-based steps may provide significant effects in improving fitness and health. s afr j sm 2014;26(3):77-81. doi:10.7196/sajsm.534 steps that count: pedometer-measured physical activity, self reported physical activity and current physical guidelines ‒ how do they relate? j d pillay,1,2 phd; t l kolbe-alexander,1 phd; k i proper,3 phd; s a tomaz,1 mphil; w van mechelen,3 phd; e v lambert,1 phd 1 uct/mrc exercise science and sports medicine research unit, faculty of health sciences, university of cape town, south africa 2 department of basic medical sciences, faculty of health sciences, durban university of technology, south africa  3 department of public and occupational health, emgo+ institute for health and care research, vu university medical centre, amsterdam, the netherlands corresponding author: j d pillay (pillayjd@dut.ac.za) studies on physical activity behaviours and their association with morbidity and mortality rates have largely been measured through self-reported (indirect) measures of physical activity using interviews, surveys, questionnaires and diaries/logs. [1,2] these measures are frequently used owing to their practicality, including low cost, low participant burden and general acceptance. [2] although self-reported data can provide useful insights into the physical activity levels of populations or subgroups, these data have the tendency to overor underestimate true physical activity energy expenditure and rates of inactivity. [1] furthermore, issues around recall and differential interpretations of terms present an evident bias. [3] self-reported measures are also usually unable to capture the absolute level of physical activity [4] and are therefore typically considered subjective. direct measures have the potential to provide more precise estimates of energy expenditure and may reduce/eliminate many of the limitations of recall-and-response bias evident in indirect measures. [5] few studies [6,7] have attempted to measure the level of agreement between self-reported measures and steps/day data as a direct/objective measure of ambulatory physical activity. [8-10] furthermore, such studies have been accelerometer based. this is primarily due to the fact that pedometers traditionally presented volume-based information, with little or no reference to intensity or duration of intensity-based ambulatory physical activity or its relationship to current physical activity guidelines. with more recent literature providing intensity-based step recommendations (such as 3 000 steps in 30 minutes), [11-13] the need to incorporate elements of current guidelines, including volume, intensity, duration and frequency of physical activity, into pedometer-based messages has therefore become an area of increased research. such research continues to strengthen so as to ensure congruency between pedometer-based recommendations and physical activity guidelines. recent advancements in pedometry create the opportunity for its use in providing more detailed information on physical activity patterns, rather than simply recording a tally of steps/day, even though it is limited to ambulatory physical activity. for example, the ability to provide information on intensity-based steps[14] may provide a more objective alternative, or complement, to self-reported approaches that typically rely on recall. using pedometers for such a purpose would also be less costly than instruments such as accelerometers, used 78 sajsm vol. 26 no. 3 2014 for providing an objective measure of ambulatory physical activity. consequently, the opportunity arose to evaluate the relationship between pedometer-determined physical activity patterns and selfreported ambulatory physical activity, in terms of volume, intensity and duration of steps/day. objectives the objectives of our study were, therefore, to compare the volume and intensity of steps/day using pedometer-measured and selfperceived (questionnaire) measures, in relation to current physical activity guidelines, and to establish the level of agreement between pedometer-measured and self-perceived ambulatory physical activity, in relation to current guidelines. methods this was a cross-sectional study among employed south african adults. participant recruitment a convenience sample of participants was recruited through an invitation email sent out to employees, or following the completion of a health risk screening hosted primarily at corporate organisations. the corporate organisations mainly comprised health-insured, whitecollar workers. the physical activity levels required by and performed in most of these jobs were low in general. pedometer wear participants were requested to wear a blinded (omron hj 720 itc) pedometer, attached to the left or right hip, as worn in most studies. [3] in order to increase the probability of obtaining at least 3 consecutive days of pedometer data – as a minimum criterion for inclusion in the data analyses [11,15,16] – a 5-consecutive-day protocol was decided as the number of days that participants were requested to wear the pedometer. participants were asked to wear the pedometer throughout the day and to follow their usual routine of daily activities, and to remove the pedometer only when bathing or showering, swimming or sleeping. participants were also informed that their daily results would be made available to them at the end of the study. inclusion and exclusion criteria employees attending the health screening event and/or willing to participate in the study were eligible for inclusion. other inclusion criteria included being between the ages of 21 years (inclusive) and 50 years (exclusive) and willingness to wear a blinded pedometer during waking hours, for the duration of the study. employees were excluded for the following reasons: pregnancy; diagnosis or treatment of cancer; any other condition that could impact on physical activity; non-compliance to the pedometer wear; and participation in non-ambulatory physical activity (such as swimming and cycling) that might not be captured or be inaccurate through the pedometer reading. ethical considerations and informed consent the study was approved by the faculty of health sciences human research ethics committee (rec 348/2008) of the university of cape town. permission was also obtained from corporate organisations to provide an onsite health screening event and to invite employees to participate in the study. employees were provided with a participant information sheet detailing the purpose, objectives, procedures, requirements and potential risks of the study. they were thereafter required to sign an informed consent form. measurements anthropometric measurements included body height, waist circumference, body weight, body mass index and percentage body fat. blood pressure (bp) and finger prick blood cholesterol and blood glucose were also measured. self-perceived physical activity a questionnaire, administered as part of the health screening event, acquired information on physical activity habits. questions relating to patterns of ambulatory physical activity enquired about the frequency (number of sessions of physical activity bouts), duration (approximate time spent in each bout) and intensity (estimated level of effort performed during each bout). this information was translated into two time-based categories, i.e. <21 minutes/day and ≥21 minutes/day of aerobic activity, as an indicator of not meeting current guidelines and meeting current guidelines, respectively. these subgroups relate to current physical activity guidelines of 150 minutes of moderateintensity physical activity/week, [17] approximated to 21 minutes/day. pedometer data recording with particular reference to intensity-based steps, recently documented literature on intensity-based steps/day [18,19] suggests a minimum of 100 steps/minute to be a reliable estimate of, and target for, moderateintensity physical activity (aerobic steps). current literature also suggests that the accumulation of moderate-intensity physical activity in bouts of at least 10 minutes is acceptable in contributing towards meeting current physical activity guidelines. [17] using the graphical display of pedometer results, we considered bouts of ≥10 consecutive minutes at a minimum average intensity of 100 steps/minute as moderate-intensity physical activity. the individual data were, as for the self-reported data, categorised into <21 minutes/day and ≥21 minutes/day of aerobic activity as an indicator of not meeting and meeting current guidelines, respectively. statistical analyses both the self-reported data and the pedometer-measured data were grouped according to those meeting guidelines and those not meeting guidelines. pedometer-determined steps/day were compared between these groups. a correlation analysis was performed to determine the extent of agreement between self-perceived and pedometer-measured physical activity. in this analysis, we compared those meeting current guidelines with those not meeting current guidelines in both pedometer-determined and self-reported data, respectively. results in summary, 312 participants (147 men and 165 women; mean (standard deviation (sd)) 37 (9) years) were included in the analysis and completed the pedometer wear for a minimum of 3 consecutive days, with at least 10 hours/day of wear. the mean (sd) steps/day accumulated in men and women were 7 476 (4 076) steps/day and 5 769 (2 759) steps/day, respectively. a total sajsm vol. 26 no. 3 2014 79 of 112 participants (35.9%) accumulated an average of <5 000 steps/ day, typically classifi ed as inactive. [18] only 41 participants (13.1%) achieved an average of ≥10 000 steps/day, typically classifi ed as moderately active. [18] within the moderately active group, most of the participants (73%) also accumulated aerobic steps. analysis of self-reported and pedometer data fig. 1 presents the self-perceived and pedometer-determined mean steps/day data for men and women according to those meeting current guidelines and those not meeting guidelines. those participants who reported meeting guidelines (n=63) accumulated signifi cantly more steps/day than those not meeting guidelines (8 753 (4 251) steps/day v. 6 022 (3 114) steps/day, respectively; p<0.0001). a similar fi nding was observed for aerobic steps (1 772 (2 020) steps/day v. 421 (1 140) steps/day, respectively; p<0.0001). even after adjusting for age, gender and total steps/ day, signifi cance was still noted in the number of aerobic steps/day between the two groups (p<0.0001). with regard to pedometer output, only 35 participants (11.2%) of the total study group accumulated aerobic steps for an average of at least 21 minutes/day, and could therefore be classifi ed as meeting current guidelines. th ese participants accumulated an average of 3 951 (2 092) aerobic steps/day compared with 282 (603) aerobic steps/day in the <21 minute/day group, respectively; p<0.0001. even aft er adjusting for age, gender and total steps/day, signifi cance was still noted in the diff erence between average aerobic steps/day accumulated in the two groups (p<0.001). participants categorised into the ≥21 minute/day group also accumulated signifi cantly more total steps/day than those not meeting guidelines (10 092 (3 445) steps/day v. 6 129 (3 302) steps/day, respectively; p<0.0001). association between pedometer-determined and self-reported ambulatory physical activity a correlation between self-reported and pedometer-measured ambulatory physical activity, using the meeting guidelines and not meeting guidelines categories, indicated that approximately 80% (n=249) of the total group did not meet guidelines, according to self-reported data. th e pedometer analysis showed that nearly 90% (n=277) did not meet guidelines. of the 63 participants (20.2%; n=312) who met guidelines (selfreported), only 27% (n=17) met guidelines according to pedometer data. th irty-fi ve participants were classifi ed as meeting guidelines (pedometer determined), but more than half of these participants (51.4%) did not meet guidelines according to the self-reported data. participants who reported meeting guidelines were, however, more likely to meet guidelines (pedometer measured) (40%) than those who reported not meeting guidelines (8%). men: not meeting guidelines (0); meeting guidelines (1) women: not meeting guidelines (0); meeting guidelines (1) men: not meeting guidelines (0); meeting guidelines (1) women: not meeting guidelines (0); meeting guidelines (1) 0 1 0 2 000 4 000 6 000 8 000 a ve ra g e st ep s/ d ay 10 000 12 000 14 000 16 000 18 000 20 000 22 000 0 1 0 2 000 4 000 6 000 8 000 10 000 12 000 14 000 16 000 a ve ra g e st ep s/ d ay a) a ve ra g e st ep s/ d ay 0 2 000 4 000 6 000 8 000 10 000 12 000 14 000 16 000 18 000 20 000 22 000 0 1 b) 0 1 0 2 000 4 000 6 000 8 000 10 000 12 000 14 000 16 000 a ve ra g e st ep s/ d ay fig. 1. steps per day in relation to physical activity guidelines: (a) self-reported; (b) pedometer determined. 80 sajsm vol. 26 no. 3 2014 discussion our findings showed that those participants who met guidelines (selfreported) accumulated an average of 2 731 more steps/day than those who did not meet guidelines (p<0.001). this difference was more marked in women (2 781 steps/day; p<0.001) than men (2 247 steps/ day; p<0.005). in a study by miller and brown [6] in 2004, a comparable outcome was noted. participants (n=185) who met guidelines took an average of 1 357 steps/day more than those who did not meet guidelines. similarly, the difference was more marked among women (1 684 steps/day) than men (1 019 steps/day). [6] a popular public health message relating to pedometry is the 10 000 steps/day concept, which shows positive health outcomes in those achieving this target compared with those not achieving 10 000 steps/day, [6,11-13] while a steps/day value of <5 000 steps/day has generally been classified as inactive. [18] within the context of the 10 000 steps/day guideline, miller and brown [6] demonstrated that the accumulation of 10 000 steps/day did not always correlate with meeting guidelines. the study reported that nearly 40% of participants who met guidelines did not reach the 10 000 steps/ day target. the study also reported that ~10% of participants who did achieve the 10 000 steps/day target did not meet guidelines. [6] this implies that a large proportion of people meeting current guidelines do not reach 10 000 steps/day, yet most people reaching 10 000 steps/day meet current guidelines. our study has shown a more exaggerated finding to that in miller and brown [6] in that 71.4% of participants who met guidelines (n=63) (self-reported), did not achieve the 10 000 steps/day target. with regard to those achieving 10 000 steps/day, our findings show a somewhat different outcome to that of miller and brown, [6] as 56.1% of participants who reached the 10 000 steps/day target (n=41) still did not meet physical activity guidelines (self-reported). only 37.1% of participants who met guidelines (n=35) according to pedometer data achieved the 10 000 steps/day target. consequently, 68.3% of participants who did not achieve the 10 000 steps/day target (n=41) did not meet guidelines (self-reported). a large proportion of those individuals achieving 10 000 steps/day were also shown not to accumulate sufficient steps at a moderate intensity. recent literature exemplifies that even in the absence of meeting the 10 000 steps/day recommendation, the impact of intensity-based steps (moderate-intensity physical activity) is significantly greater than volume alone. [12] the implication of this, in keeping with our findings, emphasises the emerging importance of intensity-based steps. as such, the need for public health messages that emphasise the importance of both intensity and volume of steps/day is particularly pertinent. study strengths this research is among the first pedometer-based studies conducted in south africa, within an urban context, that establishes the association between pedometer-measured ambulatory physical activity and selfreported information. our study has more specifically related self-reported physical activity and pedometer-determined steps/day, with consideration of both volume and intensity of daily steps accumulated, and current guidelines. the presentation of our results within this context provides a novel application to pedometer-based research that can be applied in similar future studies. the intensity-based output (from pedometer data) additionally included steps accumulated over a minimum duration and intensity. this allowed us to determine step/minute rates, so as to closely relate to moderate-intensity physical activity and current guidelines. [1719] this application is also a novel application in pedometer-based research and provides an opportunity for further application and modification. additionaly, we provide some estimate of the level of agreement between self-reported and pedometer-determined physical activity. study limitations pedometers measure ambulatory physical activity. our comparison was, therefore, limited to participants performing activities more specific to ambulation and did not include activities such as swimming, cycling and weight training. the 100 steps/minute criterion, used as a baseline criterion for moderate-intensity physical activity, may not always be a true indication of moderate-intensity physical activity at an individual level. for example, this estimate may likely be affected by factors such as aerobic fitness and heart rate response to physical activity. a number of studies that have directly measured moderate intensity as three metabolic equivalents (3 mets) have, however, concluded that 100 steps/minute is a reasonable heuristic value indicative of moderate-intensity physical activity. [13,18] the subgrouping of data according to intensity-based categories, using 21 minutes/day of aerobic activity as a proxy for current physical activity recommendations, may be viewed as a further limitation. however, this categorisation has provided some level of differentiation of ambulatory physical activity according to intensity and duration of steps/day. this has allowed us to relate volume and intensity-based pedometer data to self-reported data, with particular reference to current guidelines, as a unique application to pedometry. pedometers are typically used to measure volume of steps/day. the reliability of information on intensity-based steps and the refinement of intensity-based steps through pedometry, and the application thereof to current guidelines may raise concern. this does, however, provide some level of determining a more direct measure of intensitybased ambulatory physical activity than self-reported means, and is particularly valuable as a less costly alternative to other direct measures. conclusion our study highlights the association between self-reported physical activity patterns and objectively measured ambulatory physical activity, with particular reference to both volume and intensity of steps/day, and current guidelines. in view of our results showing a very small percentage of participants meeting current guidelines (from both pedometer data and self-reported data), further studies using a similar but broader approach could enhance the reliability of our findings. the importance of intensity-defined steps/day recommendations is highlighted. the application of such recommendations in pedometerbased interventions may provide useful insights on its effects in improving fitness and health. acknowledgements. we acknowledge the following organisations for funding this project: durban university of technology (dut) and the national research foundation (thuthuka). sajsm vol. 26 no. 3 2014 81 references 1. prince sa, adamo kb, hamel me, hardt j, gorber sc, tremblay ms. a comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review. int j behav nutri phys act 2008;5(1):56. 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[http://dx.doi.org/10.1016/j.amepre.2009.01.021] original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license gastrocnemius muscle architecture in distance runners with and without achilles tendinopathy b phillips,1 mphil; k buchholtz, 2,3 phd; tl burgess,1,4 phd 1 division of physiotherapy, department of health and rehabilitation sciences, faculty of health sciences, university of cape town, south africa 2 hpals, division of physiological sciences, department of human biology, faculty of health sciences, university of cape town, south africa 3 department of physiotherapy, lunex international university of health, exercise and sport, luxembourg 4 centre for medical ethics and law, faculty of medicine and health sciences, stellenbosch university, cape town, south africa corresponding author: b phillips (brett@brettphillipsphysio.co.za) running is a popular sport that places participants at increased risk of lower limb musculoskeletal injury. [1, 2] of the musculoskeletal injuries associated with distance running, achilles tendinopathy is common, with incidences between 7% to 53% reported in this population group. [1, 2] the exact aetiology of this condition remains unclear; however, cumulative repetitive overload associated with distance running appears to be a primary pathological stimulus. [3] during the running gait cycle, the ankle progresses from a dorsiflexed position in the initial stance phase to maximal plantarflexion in the terminal stance phase. this coincides with the triceps surae muscle complex contracting eccentrically to allow for limb deceleration and stabilisation in the initial stance phase, and concentrically for force production and forward propulsion in the terminal stance phase. [4] this results in a lengthening and shortening of the achilles tendon, allowing it to perform its spring-like function during running; however, it also exposes the tendon to high levels of repetitive loading. [4] peak achilles tendon forces between six to eight times the bodyweight have been reported during the running gait cycle, equating to a tensile force of more than 9 kn being applied to the tendon with each loading cycle. [4, 5] cumulative application of these forces across the tendon in distance running can lead to microtrauma and subsequently, tendon histopathology. [3] these histopathological changes include alterations in the cellular and extracellular structure of the tendon leading to an increasingly disordered tendon matrix, loss of tendon tensile strength and subsequently, the onset and progression of achilles tendinopathy in the athlete. [3, 5] due to the role that the triceps surae muscle complex plays in achilles tendon loading, it is logical to assume that the functional capacity of this musculotendinous unit would influence this condition’s aetiology. this assumption is supported by previous research which identified gastrocnemius weakness and inflexibility to be significantly associated with the development of achilles tendinopathy. [6, 7] a muscle’s architecture is a primary determinant of its function; therefore, these functional deficits (i.e. weakness and inflexibility) of the gastrocnemius are likely to have architectural underpinnings. [8] ultrasound imaging is a safe, reliable and valid means of assessing muscle architecture in vivo. [9-13] previous studies investigating gastrocnemius architecture in distance runners have predominantly been descriptive in nature, with the architecture of healthy populations being described. [14-17] the gastrocnemius architecture of distance runners with achilles tendinopathy has not been previously described in the literature. similarly, no comparisons have been made between the gastrocnemius architecture of distance runners with achilles tendinopathy and that of uninjured runners. therefore, we aimed to describe the gastrocnemius architecture of a group of distance runners with achilles tendinopathy and to investigate whether any differences in gastrocnemius architecture exist between distance runners with achilles tendinopathy and those with healthy achilles tendons. background: achilles tendinopathy is a common condition amongst distance runners due to the cumulative repetitive overload of the tendon. gastrocnemius weakness and inflexibility can predispose to this condition. these predisposing functional deficits could have architectural underpinnings, but the gastrocnemius architecture of distance runners with achilles tendinopathy has not been previously described or compared to the architecture of healthy distance runners. objectives: we aimed to investigate the differences in gastrocnemius architecture between distance runners with achilles tendinopathy and uninjured counterparts. methods: twenty distance runners (10 with achilles tendinopathy; 10 uninjured) were recruited to this study. ultrasound measurement of the gastrocnemius muscle architecture (pennation angle; fascicle length; muscle thickness; muscle belly length; muscle volume; physiological cross-sectional area) was performed. results: gastrocnemius medial head (gm) fascicle length was significantly greater (p = 0.02), whilst the physiological cross-sectional area (pcsa) was significantly less (p = 0.01) in the case group. gastrocnemius lateral head (gl) pennation angle (p = 0.01) and pcsa (p = 0.01) were significantly lower, whilst fascicle length was significantly greater (p = 0.01) in the case group. there were no significant between-group differences in gm and gl muscle thickness, muscle belly length, or muscle volume. conclusion: components of gastrocnemius architecture differ significantly between distance runners with achilles tendinopathy and uninjured controls in our study sample. this study cannot infer whether these results are secondary or predisposing to the condition. further longitudinal investigation is required to explore these relationships further. keywords: calf muscle, morphology, ultrasound achilles tendon s afr j sports med 2022;34:1-6. doi: 10.17159/2078-516x/2022/v34i1a12576 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a12576 https://orcid.org/0000-0002-1976-345x https://orcid.org/0000-0001-9796-2182 https://orcid.org/0000-0003-1379-405x original research sajsm vol. 34 no.1 2022 2 methods this study adhered to the ethical principles outlined in the wwa declaration of helsinki – ethical principles for medical research involving human subjects. [18] ethical approval for this study was obtained from the human research ethics committee of the faculty of health sciences, university of cape town (hrec ref: 503/2015). this study was designed as a descriptive cross-sectional study. participants twenty participants were recruited from running clubs around cape town. all participants were between 20 and 55 years old, had completed a weekly training mileage of between 15 and 50 km.wk-1 over two or more training sessions for the three months preceding the study, and considered distance running as their main sport. ten participants with symptomatic, unilateral achilles tendinopathy were recruited to the case group. the diagnosis of achilles tendinopathy was confirmed by a health professional, and a score of less than 100 on the visa-a questionnaire indicating symptomatic achilles tendinopathy. ten healthy participants were recruited as the control group. this inclusion criterion was confirmed by a score of 100 on the visa-a questionnaire indicating no symptoms of achilles tendinopathy. participants were excluded from the study if they: had a history of previous rupture of the achilles tendon or grade 3 gastrocnemius strain; symptomatic acute calf strain at the time of the study which had necessitated treatment by a health professional or altered their training regimens in the month preceding the study; had been diagnosed with a neurodegenerative or muscle wasting medical condition resulting in muscle atrophy of the lower limb. procedures participants attended a 90-minute testing session at the uct division of exercise science and sports medicine. written informed consent was obtained prior to the commencement of testing. the physical activity readiness questionnaire (par-q) and the visa-a questionnaire were completed by the participants. body mass (kg), stature (cm) and body composition (sum of seven skinfolds in cm, body fat percentage) measurements were recorded. ultrasound imaging using a siemens acuson x150 diagnostic ultrasound machine (siemens medical solutions inc, usa) was performed to assess the architecture of the gastrocnemius medial head (gm) and lateral head (gl). the reliability and validity of ultrasound imaging for the measurement of gastrocnemius architecture has been previously established. [9, 10-12] intra-rater reliability of the ultrasound testing procedures was assessed in a pilot study performed prior to the main study and was found to be high (r = 0.80 – 1.00). during testing, participants were placed in the prone lying position with their legs supported, knees fully extended and ankles held firmly against rigid footplates at an ankle joint angle of 0° (plantargrade). the participants were instructed to relax the muscles of the calf during testing. using the ultrasound scanner, the proximal and distal musculotendinous junctions were identified in the mid-sagittal plane. the corresponding area on the surface of the participants’ skin was marked with a non-permanent marker. muscle belly length was measured as the distance in a straight line over the skin between the proximal and distal musculotendinous junctions. [11] a cross-sectional, mid-belly, sagittal plane scan was performed at the area halfway between the proximal and distal musculotendinous junctions. from the mid-belly scan, the pennation angle, fascicle length and muscle thickness were measured. the pennation angle (°) was measured as the angle between a single, chosen fascicle and its insertion into the deep aponeurosis of the muscle. [10] fascicle length (mm) was measured as the length of a straight line along a single, chosen fascicle between the superficial and deep aponeuroses of the muscle. muscle thickness (mm) was measured as the distance between the superficial and deep aponeuroses of the muscle. [11] each of these was measured three times and the average was accepted as the value for these parameters. to measure gastrocnemius muscle volume (cm³), four to seven sequential, axial plane ultrasound scans were taken between the proximal and distal musculotendinous junctions. the sequential scans were performed 30 mm apart. this spacing was maintained by a testing grid placed on the calf of the participants. the anatomical cross-sectional area for each segment of the scans was measured. the volume between each of those segments was then calculated using the formula: v=⅓ x [a + √(ab + b)] x t, where a and b are the anatomical crosssectional areas of adjacent scans and t is the distance between the two scans. [11] muscle volume was calculated by adding the volumes of the sequential scans. pcsa (cm²) was not measured from the ultrasound scans directly, but calculated using the formula: pcsa=v/lƒ, where v is the total muscle volume and lƒ is the mean fascicle length. [8] the image analysis tool of the siemens acuson x150 diagnostic ultrasound machine was used to measure the architectural parameters on the ultrasound scans taken. the average of both legs was used for the statistical analyses of the gm and gl architecture, respectively. statistical analysis statistical analyses were performed using statistica software (statsoft, inc., tulsa, ok 2004; statistica data analysis software system, version 13, www.statsoft.com). all anthropometric, training history, visa-a, and gastrocnemius architecture data were tabulated and assessed for normality using the shapiro-wilkes test. data were described using mean and standard deviation. differences in descriptive data, training history and gastrocnemius architecture between the two groups were assessed using independent t-tests. typical error of measurement and 95% confidence intervals for the ultrasound measurements were calculated from repetitive scan data obtained during a pilot study undertaken before the main study. these calculations were performed using the spreadsheet ‘reliability from consecutive pairs of trials’ downloaded from www.sportssci.org. statistical significance was accepted as p < 0.05. http://www.statsoft.com/ http://www.sportssci.org/ original research 3 sajsm vol. 34 no.1 2022 results participants and training history the descriptive characteristics and training data for the two groups are depicted in table 1. there were no significant differences in age, height, body mass, the sum of seven skinfolds and body fat percentage or in any of the training parameters between the case and control groups. gastrocnemius architecture ultrasound architectural measurements of gm are depicted in table 2. fascicle length was significantly greater in the case group compared to the control group (p = 0.02). the physiological cross-sectional area was significantly less in the case group compared to the control group (p = 0.01). there were no significant differences in the pennation angle, muscle thickness, muscle belly length or muscle volume between groups. ultrasound architectural measurements of gl are depicted in table 3. the pennation angle (p = 0.01) and pcsa (p = 0.01) were significantly lower in the case group compared to the control group. fascicle length was significantly greater in the case group compared to the control group (p = 0.01). there were no significant differences in muscle thickness, muscle belly length or muscle volume between the two groups. discussion the concept that muscle architecture influences a muscle’s function is well-established in the literature. [8] bearing this in mind, the clinical associations identified between calf muscle function and achilles tendinopathy incidence would be expected to have architectural underpinnings. based on this theoretical model, hypotheses could be generated on which architectural features of gastrocnemius might be identified in the case group of this study. pennation angle higher muscle pennation angles are positively associated with a muscle’s force production. [8] reduced plantar flexor force production has been significantly associated with increased achilles tendinopathy development. [6] therefore, due to these two previously established associations, the control group of this study could be expected to have higher pennation angles than the case group. this was the case with gl, where the case group had significantly lower pennation angles than the control group. however, these findings were not replicated for gm. this finding suggests the possibility that a lower gl pennation angle could have an influence on the development of achilles tendinopathy or occur as a result of the condition. table 1. descriptive, visa-a and training characteristics of participants in the case and control groups case group (n = 10) control group (n = 10) age (years) 42.3 ± 6.5 (23 – 53) 34.8 ± 9.5 (20 – 49) mass (kg) 67.8 ± 14.9 (44.3 – 94) 73.5 ± 10.9 (52.3 – 92.9) stature (cm) 174.1 ± 9.2 (159.8 – 190.1) 175.5 ± 8.8 (161.3 – 185.3) sum of seven skinfolds (cm) 73.6 ± 28.5 (37 – 128.5) 76 ± 27.6 (38.5 – 128) body fat percentage (%) 14.3 ± 5.3 (7.4 – 25.2) 13.0 ± 5.8 (5.4 – 25.3) visa-a score (n)* 66.1 ± 14.2 (36 – 83) 100 ± 0 total 3-month training mileage (km) 444 ± 150.2 (240 – 720) 441.6 ± 120.8 (180 – 600) average weekly training mileage (km.wk-1) 37 ± 13 (20 – 60) 37 ± 10 (15 – 50) average training speed (min.km-1) 5.6 ± 0.6 (4.5 – 6.3) 5.5 ± 0.9 (4 – 7) weekly training frequency (n.wk-1) 4 ± 1 (2 – 5) 4 ± 1 (3 – 6) weekly training duration (hr.wk-1) 4 ± 2 (2 – 7) 4 ± 1 (2 – 5) data are expressed as mean ± standard deviation (range). * indicates p< 0.05 between the case and control groups. table 2. ultrasound architectural measurements of the gastrocnemius medial head (gm) of participants in the case and control groups gm architectural parameter case group (n = 10) control group (n = 10) typical error (95% ci) muscle belly length (cm) 21.8 ± 1.9 23.2 ± 2.2 0.1 (0.1 – 0.1) pennation angle (°) 18.7 ± 1.9 18.4 ± 1.7 0.8 (0.6 – 1.2) fascicle length (mm)* 63.6 ± 8 56 ± 5.3 1.2 (1 – 1.9) thickness (mm) 15.9 ± 2.4 15.4 ± 1.7 0.1 (0.1 – 0.1) volume (cm³) 103.5 ± 19.4 111.1 ± 19.8 2.7 (1.7 – 7.9) pcsa (cm²)* 16.4 ± 2.8 19.9 ± 2.5 0.8 (0.5 – 2.5) data are expressed as mean ± standard deviation. * indicates p< 0.05 between case and control groups; pcsa, physiological cross-sectional area; ci, confidence interval. table 3. ultrasound architectural measurements of the gastrocnemius lateral head (gl) of participants in the case and control groups gl architectural parameter case group (n = 10) control group (n = 10) typical error (95% ci) muscle belly length (cm) 21.4 ± 0.9 22.4 ± 2.5 0.1 (0.1 – 0.3) pennation angle (°)* 12.5 ± 1.8 14.3 ± 1.0 0.8 (0.6 – 1.2) fascicle length (mm)* 77.8 ± 9 66.2 ± 7.6 1.7 (1.3 – 2.6) thickness (mm) 12.6 ± 2.3 12.8 ± 1.1 0.1 (0.1 – 0.2) volume (cm³) 57.9 ± 10.2 70.0 ± 17.5 3.0 (1.8 – 8.7) pcsa (cm²)* 7.5 ± 1.5 10.7 ± 2.8 0.4 (0.2 – 1.0) data are expressed as mean ± standard deviation. * indicates p< 0.05 between case and control groups; pcsa, physiological cross-sectional area; ci, confidence interval. original research sajsm vol. 34 no.1 2022 4 fascicle length the physiological cross-sectional area of a muscle is directly proportional to its force production. [8] the formula for calculating a muscle’s physiological cross-sectional area (pcsa) is: pcsa = v/lƒ where v is muscle volume and lƒ is fascicle length. [19] a larger fascicle length has a negative effect on a muscle’s physiological cross-sectional area, and similarly a negative effect on a muscle’s force production. [8] previous studies have found that reduced plantar flexor force production is a significant risk factor for achilles tendinopathy. [6] this would imply that distance runners with achilles tendinopathy are likely to have longer fascicle lengths than their uninjured counterparts. our findings supported this, as significantly greater fascicle lengths of gm and gl were identified in the injured runners compared to the controls. these findings suggest that increased gastrocnemius fascicle lengths could be associated with achilles tendinopathy in distance runners. due to the cross-sectional nature of this study, we cannot speculate on whether these differences in gastrocnemius fascicle length were pre-existing of the condition or resultant from the condition. muscle thickness muscle thickness has been previously shown to correlate positively with muscle volume, physiological cross-sectional area and pennation angle. these architectural variables have also been positively associated with muscle force production and strength increases secondary to resistance training. [8] with plantar flexor weakness identified as a risk factor for achilles tendinopathy [6] and the relationship outlined above between muscle thickness and force production, it could be expected that distance runners with achilles tendinopathy would have lower muscle thickness measures than uninjured distance runners. however, this was not the case in our study, as no significant differences in gm or gl muscle thickness was found between the groups. muscle belly length reduced ankle dorsiflexion range of movement (with the knee in an extended position) has been identified as a significant risk factor for achilles tendinopathy, with a shortened gastrocnemius muscle length proposed as the restricting factor. [7] distance runners with achilles tendinopathy would therefore be expected to have shorter gastrocnemius muscle belly lengths than their uninjured counterparts. in our study, there were no significant differences in gm or gl muscle belly length between the respective case and control groups. thus, our results do not support the previous hypothesis that reduced gastrocnemius muscle belly lengths are associated with achilles tendinopathy. [7] our results could, however; suggest that the reduced dorsiflexion range of movement identified as a significant risk factor for achilles tendinopathy [7], could have an alternative underlying cause other than reduced gastrocnemius muscle belly length. another possible restrictive factor is the intrinsic mechanical properties of the tendon, namely its compliance, which could contribute to restricted ankle dorsiflexion range during functional loading of the ankle with running. [20] muscle volume larger muscle volumes have been shown to correlate positively with other architectural variables, such as pennation angle, muscle thickness and physiological cross-sectional area. similarly, muscle volume has also been associated with higher muscle force production and positive changes in force production with resistance training. [8] reduced plantar flexor force production is a significant risk factor for achilles tendinopathy. [6] because of this, the previously established correlations between muscle volume and muscle force production would suggest that the muscle volume of distance runners with achilles tendinopathy would be lower than uninjured distance runners. we found no significant differences in gm or gl muscle volume between the case and control groups. our results suggest that there is no association between gastrocnemius muscle volume and achilles tendinopathy in distance runners. physiological cross-sectional area the physiological cross-sectional area is directly proportional to a muscle’s force production capacity. [8] therefore, this architectural parameter is an important determinant of the muscle’s ability to perform its function. [8] reduced plantar flexor force production has been reported as a significant risk factor for achilles tendinopathy. [6] reduced physiological cross-sectional area could therefore be a risk factor for this condition through its directly proportional relationship to muscle force production. subsequently, distance runners with achilles tendinopathy would be more likely to have lower physiological cross-sectional areas than uninjured distance runners. we identified significantly lower physiological crosssectional areas for gm and gl in the case group compared to the control group. this finding supports the previous finding that reduced gastrocnemius strength is associated with achilles tendinopathy, as well as providing further support for a relationship between gastrocnemius architecture and achilles tendinopathy. [6] comparisons with other architectural studies the pennation angles, fascicle lengths and muscle belly lengths reported in our study were similar to those reported in previous studies investigating gastrocnemius architecture. [9-11; 14-17; 19; 20] however, the gastrocnemius muscle thicknesses, volumes and pcsa reported in our study are slightly lower than other studies in the field. [9-11; 14-17; 19; 20] this could be explained by slightly differing and non-standardised testing procedures used during the ultrasound investigation of these studies. in addition, a number of these studies utilised magnetic resonance imaging (mri) to measure some of the architectural parameters. the different imaging modalities and testing procedures utilised in gastrocnemius architecture measurement could lead to reduced validity in cross-study comparisons. original research 5 sajsm vol. 34 no.1 2022 context within muscle architecture research numerous studies have investigated the architectural parameters of the gastrocnemius muscle in healthy participants, and specifically distance runners. [9-11; 14-17; 19; 20] however, no comparative analyses have been performed on gastrocnemius architectural differences between healthy and injured distance runners, regardless of the type of pathology. therefore, most research in this area has been descriptive and non-comparative in nature. this leads to muscle architecture research having minimal clinical application currently. studies of other bodily regions have established correlations between pathology and muscle architecture. an example of such findings are alterations in the multifidus and transversus abdominis architecture that have been identified in individuals with lower back pain. [12] because of the paucity of clinically relevant research in the area of lower limb muscle architecture, this study stands out as a starting point for research in this area that could have impacts on the clinical assessment and injury prevention strategies for achilles tendinopathy. limitations the primary limitation of this study was the small sample size resulting in the study being underpowered. this reduces the internal and external validity of this study’s findings. another limitation was the study’s cross-sectional nature. this type of research design does not allow for inferences on cause and effect and does not provide us with the ability to conclude whether the differences in architecture identified between the case and control groups were predisposing or secondary to the condition of the case group. to address these limitations, it is recommended that future research is conducted longitudinally with larger sample sizes to assist in further exploring the relationship between gastrocnemius architecture and achilles tendinopathy. the perspective of this study whilst the ankle joint progresses from dorsiflexion to plantarflexion during the stance phase of the running gait cycle, muscular length does not change excessively. however, changes in the length of the achilles tendon predominantly contribute to the stretch-shortening cycle of the musculotendinous unit. [20] the muscle fascicles are the contractile units that act as tensioners of the tendon to assist this spring-like function. this indicates interplay between the muscle’s fascicles and the dynamics of tendon loading. [20] thus, the architecture and functional capacity of these fascicles would influence the loading dynamics of the achilles tendon and associated achilles tendon pathology. our study’s findings provide support for pursuing further investigation into the relationship between gastrocnemius architecture, gastrocnemius function and achilles tendinopathy. conclusion based on the findings in this study, there are significant differences in some components of gastrocnemius architecture between distance runners with achilles tendinopathy and uninjured controls. due to the cross-sectional nature of our study, we cannot comment on whether these differences were pre-existing or secondary to the condition. while theoretical models provide rationales for the findings we observed, further rigorous longitudinal investigations with larger sample sizes are needed to expand further on these relationships and provide more conclusive results. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: we would like to thank all the participants for volunteering their valuable time during the testing procedure. author contributions: bp conceived the study, carried out the ultrasound investigations and drafted the manuscript. kb assisted in the conception of the study, assisted with the preparation for the ultrasound investigations and approved the final draft. tb conceived the study, participated in its design and coordination, and approved the final draft. references 1. taunton je, ryan mb, clement db, et al. a retrospective casecontrol analysis of 2002 running injuries. br j sports med 2002; 36(2): 95 101. 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[doi: 10.1242/jeb.02340][pmid: 16916971] 15. karamanidis k, arampatzis a. mechanical and morphological properties of different muscle-tendon units in the lower extremity and running mechanics: effect of aging and physical activity. j exp biol 2005; 208(.pt.20): 3907 – 3923. [doi: 10.1242/jeb.01830][pmid: 16916971] 16. buchholtz ka, lambert mi, bosch a, et al. calf muscle architecture and function in ultra runners and low physical activity individuals: a comparative review. transl sports med 2018; 1(6),250-256. [doi: 10.1002/tsm2.45] 17. abe t, kumagai k, brechue wf. fascicle length of leg muscles is greater in sprinters than distance runners. med sci sports exer 2000; 32(6): 1125 – 1129. [doi: 0195-9131/00/3206-1125/0] [pmid: 10862540] 18. world medical association special communication. world medical association declaration of helsinki ethical principles for medical research involving human subjects. j a m a2013; 310(20): 2191 – 2194. [doi:10.1001/jama.2013.281053] [pmid: 24141714] 19. albracht k, arampatzis a, baltzopoulos v. assessment of muscle volume and physiological cross-sectional area of the human triceps surae muscle in vivo. j biomech 2008; 41(10): 2211 – 2218. [doi: 10.1016/j.jbiomech.2008.04.020] [pmid: 18555257] 20. kubo k, kanehisa h, takeshita d, et al. in vivo dynamics of human medial gastrocnemius muscletendon complex during stretch-shortening cycle exercise. acta physiol scand 2000; 170(2): 127 – 135. [doi: 10.1046/j.1365-201x.2000.00768.x] [pmid: 11114950] case report 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license acetabular fracture after cycling related falls: high index of suspicion is required to avoid missing the injury on plain radiographs j swart,1 mbchb, phd; m horak,2 llm, mbchb; r de villiers,3 mbchb, mmed; c oberholzer,4 bsc physiotherapy; a rotunno,5 mbchb, msc 1 hpals research centre. department of human biology, university of cape town, sports science institute of south africa 2 university of stellenbosch, faculty of health sciences, stellenbosch, south africa 3 sports science radiology practice, winelands radiology. newlands, cape town, south africa 4 carla oberholzer physiotherapy, medical centre, main street, clarens, south africa 5 cape sports medicine, sports science institute of south africa, newlands, cape town, south africa corresponding author: j swart (jeroen.swart@uct.ac.za) case report cycling as a medium of transport and as a competitive sport has steadily increased in recent decades.[1,2] traumatic injuries secondary to falls and collisions occur relatively frequently. the majority of these injuries are abrasions and contusions with fractures of the hand, wrist and clavicle the more common bony injuries. fractures of the ankle and lower leg also occur relatively frequently.[3,4] in comparison, fractures of the hip and pelvis are less common, with no studies to date reporting their exact incidence in this sport. injuries to the acetabulum are reported even less frequently and only two case reports with respect to cycling-related acetabular injuries have been published to date.[5,6] there have been a concerning number of accounts suggesting that habitual road cycling may predispose one to low bone mineral density in the hip and lumbar spine.[7,8] it is therefore important to have a high index of suspicion for hip and pelvis fractures when treating cycling-related traumatic injuries. we present four cases that highlight the insidious nature of acetabular fractures in cyclists and document their management and recovery. case 1 a 64-year-old competitive cyclist sustained a fall while traversing technical off-road trails while riding his mountain bike. he fell directly onto his right side, predominantly the hip and flank. he was able to continue cycling but developed progressive pain while bearing weight on the right side after completing his cycle. during an assessment at a local emergency unit an x-ray of the right hip was requested and this was reported as normal (figure 1). he was reassured and was discharged but due to ongoing severe pain, the patient contacted his sports physician, who requested a computed tomography scan of the right hip and acetabulum based on suspicion of an underlying fracture. the scan demonstrated an undisplaced fracture of the anterior column of the right acetabulum, extending into the roof of the right acetabulum. superiorly, it extended into the right iliac bone and inferiorly extended into the proximal right superior pubic ramus (figure 2). the patient was advised to use crutches with no weight bearing for a period of two weeks, followed by partial weight bearing for a further three weeks if pain-free. he was able to commence low-intensity stationary cycling after two weeks and was pain-free and able to resume all normal activities after five weeks. cycling participation as a medium of transport and as a competitive sport has steadily increased in recent decades. traumatic injuries secondary to falls and collisions occur relatively frequently. fractures of the hip and pelvis are uncommon with no studies to date reporting their exact incidence in this sport. injuries specific to the acetabulum are reported even less frequently. we present four cases that highlight the insidious nature of acetabular fractures in cyclists and document their management and recovery. the number of acetabular fractures following falls from bicycles directly onto the lateral hip result in a relatively high number of fractures. many of these may be missed due to the absence of findings on plain x-ray imaging.it is therefore important to have a high index of suspicion for hip and pelvis fractures when treating cycling related traumatic injuries. keywords: cycling, traumatic injuries, epidemiology s afr j sports med 2022; 34:1-4. doi: 10.17159/2078-516x/2022/v34i1a14526 fig. 1. case 1: x-ray of the right hip on the day of injury http://dx.doi.org/10.17159/2078-516x/2022/v34i1a14526 https://orcid.org/0000-0001-7098-0313 https://orcid.org/0000-0002-5238-884x https://orcid.org/0000-0003-2471-4983 https://orcid.org/0000-0001-6114-126x case report sajsm vol.34 no.1 2022 2 case 2 a 29-year-old competitive female cyclist sustained a fall during a crash in the peloton while competing in a road cycling race. she fell directly onto her right side, with her right hip making contact with the tarmac. she was unable to continue cycling or bear any weight on the affected right leg and was taken directly to the emergency unit. on assessment, an x-ray was requested and was reported as normal. due to progressive severe pain and continued inability to weight bear on the right leg, the patient made contact with her sports physician who requested an mri scan of the right hip and acetabulum on suspicion of a fracture. this demonstrated a fracture of the anterior column of the right acetabulum (figure 3) which was undisplaced with related bone marrow and soft tissue oedema. in addition, there was a linear fracture in the coronal plane extending through the acetabular roof (figure 4) immediately posterior to the midline as well as through the junction of the middle and anterior third of the quadrilateral plate. the patient was advised to use crutches with no weight bearing for a period of at least three weeks, followed by a period of partial weight bearing for a further three weeks if pain-free. the patient was able to commence low-intensity stationary cycling after three weeks and progressed to gentle low-force cycling outdoors after four weeks. she continued to use one crutch during weight bearing until six weeks at which time she was completely pain-free and able to resume all normal activities. case 3 a 32-year-old professional female cyclist sustained a fall during training and fell directly onto her right side, predominantly onto her hip and shoulder. she was able to continue cycling for approximately 30 minutes but with moderate pain when attempting to produce power with her right leg. she was able to weight bear with minimal pain directly after the fall but her pain increased during that same day and she reported to the emergency unit in the afternoon. following a clinical assessment, an x-ray was requested and this was reported as normal. the attending doctor had a high level of suspicion due to the patient’s occupation as a professional cyclist, the nature of her fall and her level of pain, and therefore requested a ct scan. this demonstrated an undisplaced fracture of the anterior column of the right acetabulum which extended into the iliopubic eminence. fig. 2. case 1: computed tomography scan of the right hip 2 days post injury demonstrating a fracture of the anterior column and extension into the roof of the acetabulum fig. 3. case 2: mri scan of the right hip on the day of injury demonstrating a fracture of the anterior column fig. 4. case 2: mri scan of the right hip on the day of injury demonstrating fracture of the acetabular roof case report 3 sajsm vol. 34 no.1 2022 the patient was advised to use crutches and remain nonweight bearing for one week. she was advised to increase weight bearing as the symptoms settled. after two weeks, she was able to walk without assistance. one week post-injury she commenced low-intensity training on a stationary cycle and progressed from 1h to 2.5h during the first week and to a maximum of 4h at the end of week two. three weeks post-injury she was able to return to full training outdoors and has had no further symptoms. case 4 a 68-year-old female recreational cyclist sustained a fall during training and fell onto her left side, directly onto the lateral hip. she was assessed by a physiotherapist and referred for further assessment one week later due to significant pain and disability. an x-ray of the hip and pelvis were assessed as normal (figure 5) and she was discharged with instructions to undergo mri scanning if symptoms did not resolve rapidly. the patient subsequently continued to perform activities of daily living while fully weight bearing despite ongoing pain and disability. she returned for a follow-up four weeks later, at which time an mri scan of the hip and pelvis was performed. this demonstrated an undisplaced fracture of the anterior column of the right acetabulum as well as an undisplaced fracture of the left ischial ramus, with associated reactive bone oedema, and early callus formation (figure 6). she was instructed to non-weight bear for a period of four weeks, with weekly follow-ups. she had some persistent pain, but this gradually settled. after six weeks, with a gradual transition from partial to full weight bearing her symptoms resolved and she was able to weight-bear with no pain and resume stationary cycling as well as progress with her rehabilitation exercises. discussion we present four cases which we encountered consecutively over a period of 18 months. each of these cases demonstrated a similar mechanism of injury; direct fall onto the lateral hip when falling during cycling. each case was assessed in a trauma centre and three of the four cases were re-assured following plain x-ray imaging. all four cases demonstrated a fracture of the acetabulum on ct or mri imaging. all four cases sustained a fracture of the anterior column with an extension of the fracture into the roof of the acetabulum (two cases) or anteriorly into the iliopubic eminence (two cases). following identification of the fracture each of the cases recovered without complication. in the first three cases with early diagnosis, each was able to ambulate with non-weight bearing for one-three weeks and partial weight bearing for a further two-three weeks after diagnosis. these cases were able to cycle on a stationary cycle between one and three weeks post-injury and all three cases were asymptomatic and returned to full activity between three and six weeks postinjury. one case followed a delayed recovery due to a four week delay in the diagnosis of an acetabular fracture and during which the patient continued to weight bear. during this same period of time, we did not encounter any patients who presented to our clinic with lateral hip pain following a similar mechanism of injury but where a fracture was not demonstrated. as a result, we can infer that the number of acetabular fractures following falls from bicycles directly onto the lateral hip result in a relatively high number of fractures or that when patients seek further medical attention due to significant pain following this mechanism of injury, there is a high likelihood of fracture. many of these may be missed due to absence of findings on plain x-ray imaging. despite the probability of these relatively high rates of bony injury, these patients most likely suffer no sequelae due to the stability of these fractures and the limitation in activity imposed by pain during weight bearing activity. clinicians should maintain a high index of suspicion in patients who have direct falls onto the lateral hip and subsequently experience pain with weight bearing activity. fig. 5. case 4: x-ray of the left hip one week after the injury fig. 6. case 4: 3-d ct scan of the pelvis and left hip four weeks after injury (top arrow showing acetabular fracture, bottom arrow showing ischial ramus fracture and callus formation) case report sajsm vol.34 no.1 2022 4 both ct and mri are excellent modalities to confirm or exclude these fractures. patients with confirmed fractures should be managed with non-weight bearing on the affected side for at least one week or until symptoms allow transition to relatively pain free partial weight bearing. resumption of stationary indoor cycling when symptoms allow may aid recovery by maintaining range of motion and muscle strength. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: js: conception, design, data collection, analysis, interpretation, drafting, approval. ar: data collection, analysis, drafting, approval. mh: data collection, analysis, approval. co: data collection, analysis, approval. rdv: analysis, drafting, (could not approve final version as he is deceased). references 1. pucher j, garrard j, greaves s. cycling down under: a comparative analysis of bicycling trends and policies in sydney and melbourne. j transp geogr 2011;19(2):332-345. [doi: https://doi.org/10.1016/j.jtrangeo.2010.02.007] 2. fishman e. cycling as transport. trans rev 2016;36(1):1-8. [doi: 10.1080/01441647.2015.1114271] 3. bohlmann jt. injuries in competitive cycling. phys sportsmed 1981;9(5):117-124. [doi: 10.1080/00913847.1981.11711083] [pmid: 27453026] 4. mellion mb. common cycling injuries: management and prevention. sports med 1991;11(1):52-70. [doi: 10.2165/00007256-199111010-00004] [pmid: 2011683] 5. bass a, lovell me. two cases of acetabular fractures sustained during competitive cycling. br j sports med 1995;29(3):205-206. [doi: 10.1136/bjsm.29.3.205] [pmid: 8800858] 6. cerynik dl, roshon m, abzug jm, harding sp, tom ja. pelvic fractures in professional cyclists: a report of 3 cases. sports health 2009;1(3):265-270. [doi: 10.1177/1941738108326704] [pmid: 23015883] 7. barry dw, kohrt wm. bmd decreases over the course of a year in competitive male cyclists. j bone miner res 2008;23(4):484491. [doi: 10.1359/jbmr.071203] [pmid: 18072875] 8. smathers am, bemben mg, bemben da. bone density comparisons in male competitive road cyclists and untrained controls. med sci sports exerc 2009;41(2):290-296. [doi: 10.1249/mss.0b013e318185493e] [pmid: 19127198] 30 sajsm vol. 28 no. 1 2016 original research short report incidental intima-media wall changes in the lower-limb arteries: a case series in habitual distance runners b roos1; w derman,2,3 mbchb, bsc (med) (hons), phd 1 sonographer, musculoskeletal ultrasound department, centre for orthopaedics, johannesburg, south africa 2 institute for sport & exercise medicine, division of orthopaedic surgery, faculty of medicine and health science, stellenbosch university, south africa 3 international olympic committee (ioc) research centre, south africa corresponding author: w derman (ewderman@sun.ac.za) this case series describes the observed presence of echogenic circular “beads” identified by high-resolution ultrasound imaging in the peripheral arterial walls of the lower limbs of three vascularly asymptomatic runners. the aetiology, mechanisms and clinical implications of these observations remain uncertain. keywords: ultrasound, calcification, beads, endurance runners, arterial wall s afr j sports med 2016;28(1):30-32. doi:10.17159/2078-516x/2016/v28i1a689 high-resolution ultrasound is a popular and cost effective imaging modality used in the practice of sport and exercise medicine for the evaluation of soft tissue injury. indeed, this modality is the imaging investigation of choice in the evaluation of skeletal muscle injury, aponeurotic tears, ligament injuries, tendinopathy and evaluation of soft tissue swelling. it is also an important diagnostic modality in the evaluation of vascular conditions including deep venous thrombosis and peripheral arterial disease. a number of clinical ultrasonographers including the first author of this report have (during musculoskeletal ultrasound conducted for reasons of injury evaluation) noticed the presence of echogenic circular “bead” shaped calcifications in the arterial wall (intimamedia space) of the peripheral lower limb arteries in runners. the vessels identified with this phenomenon include the posterior tibial, anterior tibial, popliteal and (to a lesser extent) the superficial femoral arteries. discussions with colleagues in the radiology, orthopaedic and vascular fields have failed to explain this finding. it has been suggested that this phenomenon might be a variant of mönckeberg’s medial sclerosis which might be exacerbated by running, however literature searches targeting this phenomenon have failed to yield many results.[1] it is of interest that a literature search did identify a study of the mechanical stress effects on the cardiovascular adaptations of peripheral arterial calcifications among athletes.[6] methods this case series describes the appearance observed in the lower limb vasculature of three runners who underwent ultrasound evaluation of the lower limb due to musculoskeletal injury. all three athletes were in a similar age group (49-52 years), of similar build and have similar histories of many years of road-running. two of the athletes are brothers, the third athlete is unrelated. all athletes underwent ultrasound scanning of the lower limb for either ankle sprain or calf strain. a philips epiq 5 ultrasound scanner (philips, netherlands) using an 18 mhz transducer with harmonic imaging was used in the imaging evaluations. all athletes described in this study provided written consent for their clinical material to be used in this publication. images captured from ultrasound scanning of the three athletes described in table 1 are shown in figures 2 to 6. as a control image, an asymptomatic 50-year-old male underwent ultrasound scanning as a means to demonstrate the normal anatomy and provide a “control”. the image from this individual is shown in figure 1. fig. 1. normal smooth intima of the posterior tibial artery of a 50-year-old physically inactive individual fig. 2. ultrasound conducted for ankle sprain of athlete 1 [note arrows show echogenic intima-media thickening (beads) in the distal posterior tibial artery] fig. 3. ultrasound conducted for ankle sprain of athlete 2. arrows indicate echogenic intima-media calcification (beads) in the left anterior tibial artery [note posterior shadowing in sections as the deposits become denser] mailto:ewderman@sun.ac.za http://dx.doi.org/10.17159/2078-516x/2016/v28i1a689 sajsm vol. 28 no. 1 2016 31 original research fig. 4. left lateral ankle x-ray post injury in athlete 2 [note incidental arterial calcifications visible] fig. 5. intimal-medial calcific bead-like deposits in the left posterior tibial artery of athlete 3 fig. 6. calcific deposits in right posterior tibial artery deposits of athlete 3 [note deposits cause shadowing, resulting in only partial visualisation of the colour doppler flow. the doppler spectral trace of flow is, however, normal.] fig. 7. ultrasound scan of the carotid artery of athlete 3 [note the smooth non-calcified vascular wall] the clinical and sporting characteristics of the three runners are shown in table 1. discussion this case series describes vascular beadlike calcifications as an incidental finding in the intima-media layers of the lower limb vasculature in three endurance runners who underwent musculoskeletal ultrasound scanning for lower limb soft tissue injury. many practicing ultrasonographers have observed this phenomenon in endurance runners. it is assumed that the nature of the hyperechoic regions described above are calcific in origin.[2] in the early stages of these lesions in younger runners, the deposits do not cause any posterior shadowing to suggest calcium as a component. it is therefore possible that the lesions seen might represent lipid or fibrotic deposits. over time, however, the deposits do cause marked shadowing on ultrasound, to the point of preventing visualisation of sections of the vessel lumen (figure 6). most of the literature describing vascular ultrasound investigations in the athletic and non-athletic populations show that they were performed as diagnostic tests secondary to the presence of vascular symptoms. for example, iliac artery stenosis in cyclists has been well researched and involves endofibrosis, a pathological process characterised by thickening of the vessel intima, causing progressive stenosis of the lumen and impaired blood flow.[3] fibromuscular dysplasia is a further disorder that has been described but predominantly affects the medial or adventitial layers of the arterial wall and typically involves the renal or extracranial cerebrovascular arteries.[4] the condition described in this series is also clearly different from cystic adventitial disease, in which mucoid cysts develop within the adventitial layer of typically the popliteal artery, increasing adventitial thickness and compromising flow.[5] mönckeberg’s sclerosis has some similar features to the cases described in this series, but tends to result in a stiffening of the elastic layer of the arterial wall. in addition, it is usually observed in the major lower limb arteries of the elderly, but can occur in the head, neck and pelvis. it is important to note that the vascular calcifications described in this series were only noted in the arteries of the lower limb and not in the carotid vessels (figure 7). it is also important to note that increased calcium and calcium scores in the coronary arteries of endurance runners has recently been described.[6] the clinical relevance of these findings is yet to be determined. it is tempting to speculate that the deposits described may be related to an inflammatory process of the arterial walls due to the repetitive jarring impact of the foot on a hard surface. however, to the knowledge of these authors, no biopsies have been performed to establish the aetiology of the deposits. acknowledgements: ms roos would like to acknowledge the support and enthusiasm of dr mark ferguson, prof mike lambert and dr jon patricios who assisted with encouragement of the first author to present these observations. thanks to the three athletes for the permission to use their data. competing interests: none. 32 sajsm vol. 28 no. 1 2016 original research table 1. characteristics of the three runners described in this series parameters athlete 1 athlete 2 athlete 3 height (m) 1.8 m 1.6 m 1.8 m weight (kg) 67 65 80 age (yrs.) 52 51 49 years running 29 25 11 constant, then intermittent short distances i.e. track + field minimal minimal 5 yrs. : 800-5000 m long distances i.e. 10 km+ multiple multiple multiple ultramarathons i.e. > 42.2 km 22 22 none marathons (42.2 km) 130 40 none half marathons (21.2 km) 400 150 several triathlons 12 ultra + 60 std 7 ultra + several std multiple std other sporting disciplines: canoe/cycle canoe/cycle/yoga swimming, cycling, gym exercise sessions per week: 7 to 12 4 5 to 7 major injuries/illness: stress # alar x 2 car/motorbike accidents lateral ligament complexes patella tendinopathy no major limb injuries both ankles 1980s bilharzia x 2 some knee + ankle issues maisonneuve # left 2010 muscles tears/sprains (arterial calcifications incidental on x-ray) (arterial calcifications incidental on x-ray) cholesterol concentration (mmol/l) 4.8 5.2 5.1 smoking habit never several years, but not for 25 years never abbreviations: m = metres km = kilometres yrs = years std = standard mmol/l = millimol per litre references 1. gielen s, schuler g, adams v. cardiovascular effects of exercise training: molecular mechanisms. circulation 2010;122:1221-1238. [http://dx.doi.org/10.1161/ circulationaha.110.939959] 2. drűeke tb. arterial intima and media calcification: distinct entities with different pathogenesis or all the same? clin j am soc nephrol 2008;3: 1583-1584. [http:// dx.doi.org/10.2215/cjn.03250708] 3. peach g, schep g, palfreeman r, et al. endofibrosis and kinking of the iliac arteries in athletes: a systematic review. eur j vascendovasc surg 2012;43:208-217. [http:// dx.doi.org/10.1016/j.ejvs.2011.11.019] 4. perdu j, boutouyrie p, bourgain c, et al. inheritance of arterial lesions in renal fibromuscular dysplasia. j hum hypertens 2007;21:393-400. [http://dx.doi. org/10.1038/sj.jhh.1002156] 5. frança m, pinto j, machado r, et al. case 157: bilateral adventitial cystic disease of the popliteal artery 1. radiology 2010;255:655-660. [http://dx.doi.org/10.1148/ radiol.10082211] 6. o’keefe jh, patil hr, lavie cj, et al. potential adverse cardiovascular effects from excessive endurance exercise. mayo clinic proc 2012;87:587-595. [http://dx.doi. org/10.1016/j.mayocp.2012.04.005] http://dx.doi.org/10.1161/circulationaha.110.939959 http://dx.doi.org/10.1161/circulationaha.110.939959 http://dx.doi.org/10.2215/cjn.03250708 http://dx.doi.org/10.2215/cjn.03250708 http://dx.doi.org/10.1016/j.ejvs.2011.11.019 http://dx.doi.org/10.1016/j.ejvs.2011.11.019 http://dx.doi.org/10.1038/sj.jhh.1002156 http://dx.doi.org/10.1038/sj.jhh.1002156 http://dx.doi.org/10.1148/radiol.10082211 http://dx.doi.org/10.1148/radiol.10082211 http://dx.doi.org/10.1016/j.mayocp.2012.04.005 http://dx.doi.org/10.1016/j.mayocp.2012.04.005 case report 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license bilateral patellar tendon rupture in a weightlifter during an acute high-loading resistance exercise bout: a case study la alexander,1 mbchb, dippec, msc (sem); jt mchunu,1 m.d; rd kgabu, 2 mbchb, fc orth; ew derman,3,4 mbchb, phd 1 orthopaedic registrar, department of orthopaedics, faculty of health sciences, school of clinical medicine, university of the witwatersrand, south africa 2 consultant orthopaedic surgeon, department of orthopaedics, faculty of health sciences, school of clinical medicine, university of the witwatersrand, south africa 3 institute of sport and exercise medicine, division of orthopaedic surgery, department of surgical sciences, faculty of medicine and health sciences, stellenbosch university, south africa 4 ioc research centre, south africa corresponding author: la alexander (laine_alexander@hotmail.com) case report bilateral patellar tendon ruptures are exceedingly uncommon, especially when they occur in individuals without predisposing risk factors or systemic disease. [1,2] due to its rarity, many cases are missed on initial presentation resulting in poor patient outcomes.[1] identifying associated risk factors could potentially mitigate this oversight.[1] understanding the mechanism of injury and having a high index of suspicion could aid accurate diagnosis. rupture typically occurs during a jumping event, when a strong quadriceps contraction is paired with a knee flexed at around 60 degrees.[3] the most frequently reported symptoms include knee pain, immediate knee swelling and difficulty bearing weight. physical examination may reveal a highriding patella, a large haemarthrosis, a palpable gap at the inferior pole of the patella, and a patient who is unable to perform a straight leg raise. treatment of complete tears and/or those with extensor mechanism disruption, is typically surgical repair.[2] we report a case of a healthy, recreational weightlifter who sustained bilateral traumatic patellar tendon ruptures. we discuss how poor load management may have predisposed our patient to this injury. history a 32-year-old male, recreational weightlifter presented with a history of severe, acute, bilateral knee pain and swelling. he reported hearing a sharp popping sound whilst attempting to perform a weighted deep squat manoeuvre the previous day. he subsequently collapsed to the floor and was unable to walk thereafter. he had no known medical comorbidities and no known risk factors associated with tendon ruptures. specifically, he denied using fluroquinolones, anabolic or corticosteroids, and reported no history of patellar tendinopathy or related injuries. a sporting history revealed that our patient only had five months of weightlifting experience and that he had significantly and rapidly increased the resistance load on the index deep squat manoeuvre from what he was previously accustomed to. his current one-repetition maximum (1rm) was 42 kg and here a weight of 84 kg was attempted. the patient had previously been training at his home gym but was afforded the opportunity to use heavier weight options at the new training facility located at his place of employment. physical examination on inspection of both knees, they appeared swollen with superiorly displaced patellae noted. the displacement and effusions were confirmed on palpation. furthermore, his knees were tender on palpation mainly over the inferior patellae poles. he was unable to perform a straight leg raise or actively extend either knee, confirming disrupted lower limb extensor mechanisms. standard clinical tests for ligament and meniscal injury were unremarkable. there was no neurovascular compromise. initial differential diagnosis included bilateral patella fractures, quadriceps tendon injuries and patellar tendon injuries. imaging and diagnosis x-rays revealed an increased insall-salvati index on both sides (left: 2.0, right: 2.1) with bony avulsion, inferior to the left patella, most likely arising from the inferior pole (fig. 1a/1b).[1] bilateral patellar tendon ruptures are exceedingly uncommon, especially when they occur in individuals without predisposing risk factors or systemic disease. due to its rarity, many cases are missed on initial presentation resulting in poor patient outcomes. identifying associated risk factors aids in diagnosis and mitigates this oversight. we report a case of a healthy, recreational weightlifter who sustained bilateral patellar tendon ruptures during an acute high-loading resistance exercise bout. we discuss how a spike in acute workload may have predisposed our patient to this injury. research into training load and athlete injury risk is currently in vogue, however, no studies have analysed whether poor load management increases the risk of tendon ruptures. this case prompts awareness for clinicians who diagnose and manage this injury and helps to stimulate the formation of educational initiatives for athletes and coaches, aimed at injury prevention. keywords: extensor mechanism, load, injury, sport s afr j sports med 2022; 34:1-3. doi: 10.17159/2078-516x/2022/v34i1a11781 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a11781 https://orcid.org/0000-0002-0885-7135 https://orcid.org/0000-0002-6837-7918 https://orcid.org/0000-0002-6284-7122 https://orcid.org/0000-0002-8879-177x case report sajsm vol.34 no.1 2022 2 a final diagnosis of bilateral patellar tendon ruptures was made. the patient was admitted to hospital, where his lower extremities were immobilised in full extension. analgesic drugs were administered and he was prepped for surgical intervention. surgery and its outcome intra-operative findings confirmed bilateral patellar tendon ruptures arising from the inferior patella poles, with an associated bony avulsion on the left (fig. 1c). acute tears are treated surgically via direct primary repair. end-to-end repairs are used for acute mid-substance tears and transosseous sutures or suture anchors are used for proximal or distal injuries. this differs from chronic tears, where reconstruction using an autograft or allograft is preferred. [3] our definitive management involved a traditional, direct primary surgical repair with non-absorbable transosseous krakow whip sutures augmented with a surrounding nonabsorbable mesh tape (fig. 1d). the retinaculum was repaired bilaterally (fig. 1e). no surgical complications resulted. after follow-ups at two, six and 12 weeks, whilst adhering to a comprehensive multidisciplinary rehabilitation plan, the patient made a full recovery. contact at six months revealed full range of motion in both knees and a successful return to his pre-injury sporting level. discussion the patellar tendon forms part of the knee extensor mechanism and consists of tightly packed parallel collagen fibres capable of significant tensile strength, such that acute rupture of a healthy tendon is extremely uncommon.[3] most ruptures occur at the inferior pole followed by the midsubstance area.[3] unilateral extensor mechanism injuries are 15 times more common than bilateral injuries.[2] with regards to weight-bearing structures, an achilles tendon rupture is far more common than a patellar tendon rupture. the low incidence is a result of the bony patella, considered the weakest part of the extensor mechanism, failing before the adjacent tendinous components.[4] patellar tendon rupture cases are distributed bimodally. seventy percent are seen in the seventh decade of life and are mostly related to spontaneous ruptures associated with chronic medical conditions (e.g. renal disease or systemic lupus erythematosus) or medication use (e.g. fluroquinolones).[1,2] the remainder of cases are seen in individuals under the age of 40 during sports such as netball and weightlifting. in athletes, tendon rupture is usually the result of long-standing chronic tendon degeneration due to repetitive microtrauma and subsequent tendinopathy.[1] other athletes at risk are those using anabolic agents or corticosteroids. however, due to these agents being banned in sport and subsequent non-disclosure, their true incidence related to tendon rupture is unknown. despite specific enquiry, none of these risk factors were demonstrated in our patient. notably, our patient was very inexperienced and had never received guidance on how to formulate a safe training programme or how to complete these movements with correct techniques and form. our patient’s index repetition was 110% heavier than his 1-rm which was a substantial and rapid increase in resistance, ultimately resulting in his injury. the principle of tissue overload is widely practiced in sport and involves the application of gradually increasing stress over time to the body, over and above that which is normally encountered, to elicit physiological adaptation and subsequent performance improvement. furthermore, load management is increasingly being recognised for its fundamental role in injury prevention.[5] gabbett et al. found that if weekly training load was increased by more than 15% in some athletes, their injury risk may increase by up to 49%. therefore, they recommend that athletes should limit weekly training load increases to <10%.[5] rabello et al. demonstrated a relationship between increases in weekly training load and a participant’s patellar tendon structure using ultrasound tissue characterisation techniques. they concluded that these structural changes may correlate with an increased risk of tendon-related injuries.[6] these studies support our belief that the acute rate of significant load increase played a pivotal role in our patient sustaining his injuries. figs. 1a/1b. lateral knee x-rays showed increased insall-salvati index (left: 2.0, right: 2.1).[1] fig. 1c. intra-op findings of a patellar tendon rupture occurring at the inferior pole, with damage to the retinaculum. fig. 1d. left and right patellar tendons were repaired surgically using non-absorbable suture krakow stiches. fig. 1e. the repair was re-enforced with non-absorbable mesh tape arranged in a figure-of-eight pattern around the circumference of the patella and through a horizontal drill-hole in the tibial tubercle. case report 3 sajsm vol. 34 no.1 2022 conclusion patellar tendon ruptures are uncommon, and bilateral concurrent pathology is considered extremely rare.[2] this case accompanies a select few reports which detail a sports-related bilateral patellar tendon rupture.[1,3] furthermore, despite the increasing popularity in sports using muscle power, there have been no published reports of this injury in amateur or professional weightlifters. when clinicians are confronted with an amateur athlete, a thorough sporting history may help in identifying a potential risk factor, such as poor load management and assist in confirming this rare diagnosis. athletes should be counselled on how anabolic agents, corticosteroids and fluroquinolones increase one’s risk of tendon rupture. educational initiatives which focus on safe training practices for injury prevention should be formulated. this report highlights the paucity of literature available on bilateral patellar tendon ruptures during acute high-loading resistance exercise and it provides a framework for future research into load management and tendon injuries. the report also creates awareness for orthopaedic surgeons, emergency medicine physicians and sports physicians who diagnose and manage these injuries. ethical approval: the study was approved by hrec of the university of the witwatersrand (m200683) and the helen joseph hospital ethics committee. conflict of interest and source of funding: the author declares no conflict of interest and no source of funding. acknowledgements: the authors would like to thank our patient for his consent to use his clinical data in this case study. author contributions: la: obtaining case information, writing of manuscript, design and layout, interpretation of data, drafting and critical revision of manuscript content, approval of version to be published. jtm: interpretation of data, critical revision of orthopaedic content, approval of version to be published. rk: conception, interpretation of data, critical revision of manuscript content, approval of version to be published. wd: design, interpretation of data, critical revision of manuscript content, approval of version to be published. references 1. camarda l, arienzo ad, morello s, et al. bilateral ruptures of the extensor mechanism of the knee: a systematic review. j orthop 2017; 14(14):445-453. [doi: 10.1016/j.jor.2017.07.008] [pmid: 28819342] 2. monroy a, urruela a, egol ka, et al. bilateral disruption of soft tissue extensor mechanism of knee: functional outcome and comparison to unilateral injuries. hss j 2013; 9 (1): 12-16 [doi: 10.1007/s11420-012-9314-8] [pmid: 24426838] 3. pengas ip, assiotis a, khan w, et al. adult native knee extensor mechanism ruptures. injury 2016; 47(10):2065–2070. [doi: 10.1016/j.injury.2016.06.032][pmid: 27423309] 4. clayton ra, court-brown cm. the epidemiology of musculoskeletal tendinous and ligamentous injuries. injury 2008;39(12):1338–1344. [doi: 10.1016/j.injury.2008.06.021] [pmid:19036362] 5. hulin bj, gabbett tj, lawson dw, et al. the acute:chronic workload ratio predicts injury: high chronic workload may decrease injury risk in elite rugby league players. br j sports med 2016;50(4):231–236. [doi: 10.1136/bjsports-2015-094817] pmid: 26511006] 6. rabello lm, zwerver j, stewart re, et al. patellar tendon structure responds to load over a 7 ‐ week preseason in elite male volleyball players. scand j sci sport 2019; 29(7):992–999. [doi: 10.1111/sms.13428] [pmid: 30942914] original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license changes in training activity post covid-19 infection in recreational runners and cyclists a emeran,¹,²,³ bsc (hons); ev lambert,¹,² phd; t paruk,¹,² msc; a bosch,¹,² phd ¹ uct research centre for health through physical activity lifestyle and sport (hpals), department of human biology, faculty of health sciences, university of cape town, cape town, south africa 2 international federation of sports medicine (fims) collaborative centre of sports medicine, university of cape town, cape town, south africa 3 national research foundation (nrf), cape town, south africa corresponding author: a bosch (andrew.bosch@uct.ac.za) the covid-19 pandemic has had a major impact on morbidity and mortality globally.[1] fortunately, most covid-19 cases have been classified as mild to moderate.[2] however, even with mild illness severity, individuals may still require a prolonged time to full recovery, particularly when returning to exercise. anecdotal evidence shows that many individuals, including athletes, have difficulty returning to their normal level of exercise post infection.[3] symptoms challenging athletes’ return to exercise include coughing, tachycardia, and fatigue.[4] there is limited research on the effect of covid-19 on the exercise activity of athletes post infection, with several studies reporting minimal impairment of exercise capacity on cardiopulmonary exercise testing (cpet) in athletes post covid-19.[5,6] to our knowledge, no research has been undertaken on objectively measured training data obtained from runners and cyclists preand post covid-19 infection. the current study aims to address the gap in knowledge for the above by describing the perceptions of recreational runners and cyclists recovering from covid-19 on their training activity and general well-being. in a sub-sample, we will compare objectively measured training data in runners and cyclists preand post covid-19 infection with non-infected controls who experienced a training interruption. the study differs from existing studies, as instead of using exercise testing, exercise data from participants’ global positioning system (gps) wearable devices were used to determine whether a change in exercise activity occurred post infection. to our knowledge, this is the first study to measure exercise activity of athletes preand post infection using gps wearable data. this study will potentially drive interest in conducting further studies on different populations and in various sporting fields using similar methods to better understand the potential impact of the sars-cov-2 virus on the exercise activity of athletes. methods study design and participants the study is an observational study on recreational runners and cyclists predominantly from south africa (two international participants were included). participants were recruited using convenient, non-randomised sampling, via emailing running and cycling clubs in south africa, and advertising the study on social media and at the sports science institute of south africa. the advertisement included a basic description of the study and a link to the study’s website. the website page contained links to the study’s participation information sheet containing instructions on how to download their gps data, the informed consent form, and a study questionnaire via google forms. inclusion criteria were runners and cyclists over the age of 18 that reportedly tested positive for covid-19, had attempted to return to exercise post infection, and used a gps wearable device that measures heart rate. a control group that had not been infected with covid-19 but had an interruption in training of two weeks or more was also included in the study. training interruption was defined as a complete cessation of running or cycling training, not associated with covid-19 infection. all participants provided informed consent via the study’s online google forms questionnaire. the study received ethics approval from the faculty of health sciences human research background: anecdotal evidence suggests that athletes struggle to return to exercise post covid-19 infection. however, studies evaluating the effect of covid-19 on athletes’ exercise activity are limited. objectives: the objectives of this study were: (i) to describe the perceptions of recreational runners and cyclists recovering from covid-19 on their training activity and general wellbeing, (ii) to compare device-measured training data in runners and cyclists preand post covid-19, with noninfected controls that had a training interruption. methods: participants who were recruited via social media completed an online questionnaire (n=61), including demographic, health and covid-19 descriptive data. in a sub-sample, device-measured training data (heart rate, time, distance and speed, n=27) were obtained from gps devices for four weeks before infection and on resumption of training. similar data were collected for the control group (n=9) whose training had been interrupted but by factors excluding covid-19. results: most participants experienced a mild to moderate illness (91%) that was associated with a training interruption time of two-four weeks. decreases in heart rate, relative exercise intensity, speed, time and distance were observed during the first week of returning to training for both groups, followed by an increase from week two onwards. discussion: results failed to support a ‘covid-19 effect’ on exercise activity as reductions in training variables occurred in both the covid-19 and control groups. a possible explanation for the reductions observed is a deliberate gradual return to training by athletes post-covid-19. conclusion: more research is needed using device-measured training data prior to and post covid-19 infection to better understand the impact of the sars-cov-2 virus on the exercise activity of athletes. keywords: sars-cov-2, coronavirus, physical activity, training activity, relative exercise intensity s afr j sports med 2022;34:1-7. doi: 10.17159/2078-516x/2022/v34i1a13758 mailto:andrew.bosch@uct.ac.za http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13758 https://orcid.org/0000-0003-2217-6608 https://orcid.org/0000-0003-4315-9153 https://orcid.org/0000-0002-9543-9408 https://orcid.org/0000-0001-9073-702x original research sajsm vol. 34 no.1 2022 2 ethics committee at the university of cape town (ref. no. 409/2021). this study complies with the latest version of the declaration of helsinki (2013), as well as the department of health: ethics in health research: principles structures and processes (2004). this study was a “proof-of-concept study”. thus, a sample size calculation was not performed. questionnaire a questionnaire on google forms was provided for the participants to complete. demographic, health, and training self-reported data were obtained. for the 42 persons who reported having tested positive for covid-19, additional data were captured, including the duration of their covid-19, covid-19 symptoms, and covid-19 severity. for the control group, the reason for their training interruption and training interruption duration were also obtained. gps data participants were required to download their gps wearable device data by following the instructions provided in the participation information sheet. thereafter, participants sent their training data to the researcher to be analysed. participants were required to send gps data from four weeks pre-training interruption to four weeks post return to training. raw data were sorted and filtered on microsoft excel (version 2110) to include the following variables: average and peak heart rate during training per week (bpm), average and maximum speed per week (min/km), total time training per week (min), total distance per week (km), with variables being averaged for each week. change in training activity was measured by comparing the above training variables pre and post-training interruption. relative exercise intensity was determined by calculating age-corrected maximum heart rate using the hunt equation (211-0.64*age)[7] and dividing the average heart rate for each week by the maximum heart rate. statistical analysis the program ibm spss statistics 27 and graphpad prism 9 were used to conduct statistical analyses. data were expressed as number and percentage for categorical variables and mean and standard deviation for continuous variables. pearson chisquared tests and independent t-tests were used to determine any differences in categorical and continuous variables between the two groups. repeated measures analysis of variance (anova) was run to determine within-group and between-group differences in the gps data of participants. correlations were determined using spearman’s rank correlation tests. statistical significance was set at a p-value of <0.05. results a total of 61 participants provided consent to participate in the study and completed the questionnaires, with 42 individuals being in the covid-19 group, and 19 in the control group. of those that completed the questionnaire, 38 participants provided their gps data (covid-19: n=27; controls: n= 11). the data of two control participants were removed prior to analysis due to training data not meeting inclusion criteria, reducing the gps control sample to nine. questionnaire covid-19 and control group characteristics no statistically significant differences were found in baseline characteristics of participants (p>0.05) (table 1). most participants in both groups were above the age of 40 (~70%), were male (~74%), had a normal bmi (~67%), and were runners (~48%). most participants used garmin wearable devices (without a chest strap to measure heart rate, ~59%). the most frequent training interruption length was between 2-4 weeks for the covid-19 group (45%), and 1-3 months for the control group (32%) (p=0.054). the most common cause of training interruption for the control group was covid-19 lockdown restrictions. table 1. demographic and training characteristics of the covid-19 and control group characteristics covid-19 n=42 control n=19 p value age (years) 19-29 30-40 40-50 50-60 >60 3 (7) 11 (26) 17 (41) 10 (24) 1 (2) 1 (5) 4 (21) 6 (32) 7 (37) 1 (5) 0.806 sex male female 27 (64) 15 (36) 16 (84) 3 (16) 0.114 bmi (kg/m²) underweight normal weight overweight obese 1 (2) 28 (67) 10 (24) 3 (7) 0 (0) 13 (68) 3 (16) 3 (16) 0.605 sport runner cyclist runner and cyclist 20 (48) 5 (12) 17 (41) 9 (47) 2 (11) 8 (42) 0.985 chest strap yes no 19 (45) 23 (55) 7 (20) 12 (63) 0.539 training interruption time (weeks) 0-2 weeks 2-4 weeks 1-3 months >3months 10 (24) 19 (45) 13 (31) 0 (0) 1 (5) 5 (26) 8 (32) 5 (26) 0.054 reasons for training interruption of control group lockdown restrictions illness (excluding covid-19) injury other 14 (74) 1 (5) 1 (5) 3 (16) data are shown as the number of participants and column percentage (%). p values from pearson chi-squared test. underweight, <18.5kg/m2; normal weight, 18.5-29.9kg/m2; overweight, 25-29.9kg/m2; obese, >30kg/m2. original research 3 sajsm vol. 34 no.1 2022 covid-19 group characteristics table 2 shows health and covid-19 related characteristics of the covid-19 group. most participants had no comorbidities (69%) and were unvaccinated before and after being infected with covid-19 (57%). the most frequent acute covid-19 symptoms reported were headaches (79%), body aches (74%), and fatigue (74%). symptom duration was most frequently between 02 weeks (60%). covid-19 severity was mild to moderate for most participants (91%) with only one participant being hospitalised. the type of treatment reported varied, with most participants using over-the-counter medication such as paracetamol (56%). about 58% of participants said that they followed guidelines for return to training from their doctors. however, only 16% of participants reported being medically screened before returning to exercise. the most frequent symptoms reported when returning to training were increased heart rate (58%), and fatigue (53%). positive correlations were found between covid-19 severity and number of symptoms (r=0.50 [95% ci= 0.21-0.70]; p=0.001), symptom duration (r=0.55 [95% ci=0.27-0.74]; p<0.001), and training interruption time (r=0.52 [95% ci= 0.240.72]; p<0.001). there were also correlations between number of symptoms and symptom duration (r=0.42 [95% ci=0.12-0.65]; p=0.006), and interruption time (r=0.49 [95% ci=0.200.70]; p=0.001). gps data training interruption time there was a statistically significant difference in the training interruption time between the covid-19 group and the control group with gps data. the control group had a longer training interruption time than the covid-19 participants (33 ± 11 days vs 20 ± 13 days, table 2. comorbidities, covid-19 presentation, and treatment in the covid-19 group (n=42) n (%) comorbidities* diabetes 1 (2) high blood pressure 3 (7) cholesterol 4 (10) obesity 1 (2) asthma 8 (19) autoimmune disease 0 (0) none 29 (69) covid-19 presentation covid-19 symptoms* cough 25 (58) fever 23 (54) sore throat 21 (49) fatigue 32 (74) body aches 31 (74) loss of taste or smell 21 (49) headache 34 (79) diarrhoea 8 (19) difficulty breathing 12 (28) chest pain 12 (28) other 4 (9) none 1 (2) number of symptoms 5 ± 2 symptom duration 0-2 weeks 25 (60) 2-4 weeks 12 (29) 1-3 months 2 (5) >3 months 3 (7) covid-19 severity asymptomatic 2 (5) mild 20 (48) moderate 18 (43) severe 2 (5) critical 0 (0) symptoms when returning to training* cough 3 (7) fatigue 23 (54) shortness of breath 12 (28) increased heart rate 25 (58) other 3 (7) none 6 (14) treatment and protective measures hospitalisation yes 1 (2) no 41 (98) treatment* corticosteroids 8 (18) antibiotics 7 (16) oxygen 2 (5) over the counter medication 24 (56) ivermectin 4 (10) vitamins/supplements 15 (35) none 6 (14) fully vaccinated pre covid-19 3 (7) post covid-19 15 (36) not vaccinated 24 (57) guidelines followed before returning to training yes, guidelines from medical practitioner 23 (58) yes, guidelines from scientific journal articles 3 (7) yes, guidelines from internet 3 (7) no 13 (31) medical screening before return to training yes 7 (17) no 35 (83) data are shown as the number of participants and percentage (%) or as mean ± sd. * participants can fall into multiple categories. covid-19 severity: asymptomatic, no symptoms but tested positive for covid-19; mild, had flu-like symptoms excluding shortness of breath at rest or during exertion; moderate, flu-like symptoms and/or shortness of breath, may or may not be hospitalized; severe, requires hospitalization and oxygen administration; critical, requires hospitalization and ventilation, multi-organ involvement may be present.[8,9] original research sajsm vol. 34 no.1 2022 4 p=0.014) as mentioned previously, the most common reason for a training interruption for the control group was lockdown restrictions, with other reasons for training interruptions including injury and illnesses other than covid-19. there were no other differences in baseline characteristics such as age, sex, and bmi. peak heart rate, average heart rate, and relative exercise intensity decreases in peak and average heart rate, and relative exercise intensity were observed in both groups, one-week post return to training, compared to one-week pre-training interruption. (mean peak heart rate: covid-19:171 beats per minute (bpm) to 158 bpm; control:178 bpm to 161 bpm. mean average heart rate: covid-19:147 bpm to 140 bpm; control:146 bpm to 138 bpm. mean relative exercise intensity: covid-19:80% to 76%; control: 82%-77%). these decreases were statistically significant in both groups for peak heart rate (p=0.017), but not statistically significant for average heart rate and relative exercise intensity (p=0.095; p=0.091). following the above decreases at one week post return to training, increases in peak and average heart rate, and relative exercise intensity (figure 1) were observed in both groups from the second to the fourth week post return to training (mean peak heart rate: covid-19: 158 bpm to 172 bpm; control: 160 bpm to 177 bpm. mean average heart rate: covid-19: 140 bpm to 149 bpm; control: 138 bpm to 150 bpm. relative exercise intensity: covid-19: 76% to 80%; control: 77% to 84%) these increases were statistically significant in both groups for all three variables (p<0.04), and variables increased close to their original values pre-training interruption. no between-group differences were found for peak heart rate, average heart rate and relative exercise intensity (p=0.182; p=0.360; p=0.338). maximum and average speed maximum and average speed were analysed separately for runners and cyclists due to the difference in the nature of training modality (cyclists’ speed is naturally faster than runners’ speed). cyclists’ maximum and average speeds were omitted from analysis due to a very small sample size as a result of missing data values (n=6). a non-statistically significant decrease in maximum and average speed was observed (increase in min/km) for runners in both groups, at one week post return to training, compared to one week pretraining interruption (mean maximum speed: covid-19: 4.36 min.km-1 to 5.99 min.km-1; control: 5.41 min.km-1 to 5.98 min.km-1; p=0.07). mean average speed:covid-19: 6.45 min.km-1 to 9.26 min.km-1; control: 7.40 min.km-1 to 8.98 min.km-1; p=0.066). this was followed by a non-statistically significant increase in maximum and average speeds at weeks two to four post return to training. the covid-19 group had a faster average speed than the control group pre-training interruption (figure 2.). however, no statistically significant group effect was found at any point in training (p=0.132). fig. 1. change in relative exercise intensity of covid-19 and control groups four weeks pre interruption to four weeks after return to training post interruption; *statistical significant differences in relative exercise intensity between one week post return to training, and two, three and four weeks post return to training (p=0.03); ti: training interruption period; error bars 95% confidence interval. fig. 2. change in average speed of covid-19 and control groups four weeks preinterruption to four weeks after return to training post interruption. ti: training interruption period; error bars 95% confidence interval. original research 5 sajsm vol. 34 no.1 2022 training time and distance a statistically significant decrease in training time (p<0.001) and distance (p=0.002) was observed in the control group, one week post return to training compared to one week pretraining interruption (time trained: 291 min to 59 min; distance: 77 km to 23 km). in contrast, a non-statistically significant decrease in time and distance was observed in the covid-19 group, at one week post return to training compared to one week pre-training interruption (time: 153 min to 109 min; distance: 33 km to 14 km). additionally, the distance and time trained at one week pre-training interruption were statistically significantly different between the two groups (p=0.002; p=0.003) (figures 3 and 4). the decreases in both groups were followed by increases in time and distance trained from week two to four post return to training. however, these increases were not statistically significant for either group. for the covid-19 group, the participants appeared to recover their pre-interruption training time and distance levels. however, the control group’s training time and distance remained lower than their pre-training interruption values (figures 3 and 4). discussion questionnaire covid-19 clinical presentations the findings of this study show that the covid-19 clinical presentation in recreational runners and cyclists was mild to moderate (90%) with fatigue, body ache and headache being the most common symptoms, and 0-2 weeks being the most frequent symptom duration. this clinical presentation correlates with findings in previous studies on athletes post covid19 infection. studies by schwellnus et al.[10] and hull et al.[11] both observed headache and fatigue as one of the most prevalent covid-19 symptoms in athletes, with athletes having predominantly mild illness severity.[10,11] a possible reason for the milder illness severity found in athletes is that regular exercise of moderate intensity can potentially improve one’s immune response to infection, decrease inflammation, and reduce the risk of metabolic conditions, such as diabetes and obesity, which are considered risk factors for severe covid-19.[12] the correlations with covid-19 severity found in this study also suggest that the more severe the illness, the longer the training interruption time, the greater the number of symptoms, and the longer the symptom duration. gps data in the first week of the return to training, decreases in peak and average heart rate, relative exercise intensity, maximum and fig. 3. change in time trained of covid-19 and control groups four weeks pre-interruption to four weeks after return to training post interruption; *statistical significant difference in time trained for the control group, between one week pre-training interruption and one week post return to training (p<0.001);**statistical significant difference in time trained between the two groups at one week pre-training interruption (p=0.002) ti: training interruption period; error bars 95% confidence interval. fig. 4. change in distance trained of covid-19 and control groups four weeks preinterruption to four weeks after return to training post interruption; *statistical significant difference in distance trained for the control group, between one week pre-training interruption and one week post return to training (p=0.002);**statistical significant difference in distance trained between the two groups at one week pre-training interruption (p=0.003) ti: training interruption period; error bars 95% confidence interval. original research sajsm vol. 34 no.1 2022 6 average speed, time, and distance were observed for both the covid-19 and control groups, compared to one week pretraining interruption. because these decreases were observed in both the covid-19 and control groups, this suggests that there was no specific ‘covid-19’ effect on training activity post infection in this group of athletes. the above decreases were then followed by increases in all training variables at weeks two to four post return to training. a possible reason for the decreases in the measured training variables at week one post return to training, could be a conscious choice of the athletes to start training at a lower volume and intensity compared to before the covid-19 infection and training interruption. this hypothesis is further strengthened by the ability of athletes to increase their training values back to pre-training interruption values, suggesting a maintained exercise ability. furthermore, 58% of participants in the covid-19 group said that they followed the guidelines for return to training from their doctors, which could also be a reason for their gradual return to training. based on the results, it could be suggested that following a gradual return to training post covid-19 infection is a safe and beneficial way to approach returning to training, as participants were able to return to their original levels of training by four weeks post training interruption. in contrast, the control group did not return to their original values for time and distance trained, with values being lower than pre-training interruption values. this could possibly be due to the control group having a longer time off than the covid-19 group (33 ± 11 days vs 20 ± 13 days, p=0.014), thus making it more difficult to return to original values pretraining interruption. this could potentially be due to a detraining effect. detraining is the partial or complete reversal of physiological adaptations induced from training, due to a reduction or cessation of training stimuli.[13] however, the peak and average heart rates and relative exercise intensity after the training interruption remained similar to the pretraining interruption values. one would expect an increase in heart rate if detraining occurred. therefore, it is more likely that the control group was less motivated to return to their original levels of exercise due to the prolonged time off training, as opposed to a detraining effect. in conclusion, the data above suggest that covid-19 infection is associated with an interruption in training in recreational runners and cyclists. however, covid-19 did not have a more serious effect on return to training compared to other forms of training interruption. study limitations this study has several limitations that may influence the validity of the results. many of the changes in training variables over time were not statistically significant, with the confidence intervals of training values being wide. this is most likely due to the small sample sizes. furthermore, the study did not include any objectively physiologically measured data, such as data from cardiopulmonary exercise testing. researchers were also limited by the data provided by the participants, which contained a limited number of training variables. having variables such as resting heart rate and time trial data would have been beneficial. additionally, the training load pre-training interruption and the training interruption time of the covid-19 and control groups were not matched, with the control group having a larger time and distance trained pre-training interruption and a longer training interruption time. additionally, gps wearable heart rate measurements are known to often be inaccurate when the optical wrist-based pickup is used rather than a chest strap.[14] furthermore, equations used to calculate age-corrected maximum heart rate could result in overestimations or underestimations of readings.[15] other limitations include the small sample size of participants, which further decreased during the analysis due to missing data values. in addition, the control group’s sample size is much smaller than the covid-19 group, thus decreasing the comparator group effect. despite its limitations, this study shows the value of using gps wearable training data to determine the effect of covid-19 on the training activity of athletes post infection. future studies could improve on the current study by recruiting a larger number of participants, including resting heart rate and time trial data and matching the training loads and interruption times of cases and controls. conclusion to our knowledge, this is the first study investigating the effect of covid-19 on the training activity of recreational athletes using gps data. most participants had mild to moderate covid-19, with associations found between covid-19 severity and number of symptoms, symptom duration, and training interruption time. covid-19 was also associated with a self-reported training interruption time of two-four weeks. at one week post training interruption decreases in peak and average heart rate, relative exercise intensity, maximum and average speed, time and distance trained were observed for both the covid-19 and control groups. this was followed by an increase in these variables between two to four weeks’ post return to training in both groups. the decreases in training variables were observed for both groups, thus eliminating the possibility of a specific ‘covid-19 effect’ on training activity post infection. a possible reason for the pattern of changes observed in training variables post covid-19 could be participants deliberately returning to exercise at lower volumes and intensities in order to return to training safely. the study demonstrates the value of using gps wearable device data to evaluate athletes’ training activity post training interruptions. however, due to the many limitations of the study, the results should be taken with caution, with more research being required to further expand on the study's results. conflict of interest and source of funding: the authors declare no conflict of interest. this work is based on the research supported wholly by the national research foundation of south africa (nrf) (mnd200804549962). acknowledgements: the authors would like to extend their gratitude to the university of cape town and the nrf for the enablement of this study. additionally, we would like to thank the participants for completing the study questionnaire and sharing their gps data for analysis. original research 7 sajsm vol. 34 no.1 2022 author contributions: all authors contributed to the design of this research and the writing of the article ((i) conception, design, analysis, and interpretation of data; (ii) drafting or critical revision for important intellectual content; and (iii) approval of the version to be published. references 1. world health organisation. world health organisation coronavirus (covid-19). geneva: world health organisation, 2021. https://www.afro.who.int/health-topics/coronaviruscovid-19 (accessed 7 april 2021) 2. metzl jd, mcelheny k, robinson jn, et al. considerations for return to exercise following mild-to-moderate covid-19 in the recreational athlete. hss j 2020;16(suppl 1):102–107. [doi: 10.1007/s11420-020-09777-1] [pmid: 32837412] 3. salman d, vishnubala d, le feuvre p, et al. returning to physical activity after covid-19. bmj 2021;372 m4721. [http://dx.doi.org/10.1136/bmj.m4721] [pmid: 33419740] 4. wilson mg, hull jh, rogers j, et al. cardiorespiratory considerations for return-to-play in elite athletes after covid19 infection: a practical guide for sport and exercise medicine physicians. br j sports med 2020;54:1157–1161. [doi: 10. 1136/ bjsports2020102710] [pmid: 32878870] 5. milovancev a, avakumovic j, lakicevic n, et al. cardiorespiratory fitness in volleyball athletes following a covid-19 infection: a cross-sectional study. int j environ res public health 2021;18(8):4059. [doi: 10.3390/ijerph18084059] [pmid: 33921458] 6. komici k, bianco a, perrotta f, et al. clinical characteristics, exercise capacity and pulmonary function in post-covid-19 competitive athletes. j clin med 2021;10(14):3053. [doi: 10.3390/jcm10143053] [pmid: 34300219] 7. nes bm, janszky i, wisløff u, et al. age-predicted maximal heart rate in healthy subjects: the hunt fitness study. scand j med sci sports 2013;23(6):697-704. [doi: 10.1111/j.16000838.2012.01445.x] [pmid: 22376273] 8. löllgen h, bachl n, papadopoulou t, et al. recommendations for return to sport during the sars-cov-2 pandemic. bmj open sport exer med 2020;6(1):e000858 [doi:10.1136/bmjsem-2020000858] [pmid: 34192007] 9. national institutes of health. clinical spectrum of sars-cov-2 infection. national institute of health 2021; https://www.covid19treatmentguidelines.nih.gov/overview/clini cal-spectrum/(accessed august 2021) 10. schwellnus m, sewry n, snyders c, et al. symptom cluster is associated with prolonged return-to-play in symptomatic athletes with acute respiratory illness (including covid-19): a cross-sectional study-aware study i. br j sports med 2021; 55(20): 1144-1152. [doi: 10.1136/bjsports-2020-103782] [pmid: 33753345] 11. hull jh, wootten m, moghal m, et al. clinical patterns, recovery time and prolonged impact of covid-19 illness in international athletes : the uk experience. br j sports med 2022; 56(1): 4-11. [doi:10.1136/ bjsports-2021-104392] [pmid: 34340972] 12. brandenburg jp, lesser ia, thomson cj, et al. does higher selfreported cardiorespiratory ftness reduce the odds of hospitalization from covid-19? j phys act health 2021;18 (7):782–788. [doi: 10.1123/jpah.2020-0817] [pmid: 33984837] 13. chen yt, hsieh y-y, ho j-y, et al. two weeks of detraining reduces cardiopulmonary function and muscular fitness in endurance athletes. eur j sport sci 2022; 22(3): 399-406. [doi: 10.1080/17461391.2021.1880647][ pmid: 33517866] 14. wang r, blackburn g, desai m, et al. accuracy of wrist-worn heart rate monitors. jama cardiol 2017; 2(1):104–106. [doi: 10.1001/jamacardio.2016.3340] [pmid: 27732703] 15. nikolaidis pt, rosemann t, knechtle b. age-predicted maximal heart rate in recreational marathon runners: a cross-sectional study on fox’s and tanaka’s equations. front physiol 2018; 9: 226. [doi: 10.3389/fphys.2018.00226] [pmid: 29599724] position statement 1 sajsm vol. 34 no. 1 2022 creative commons attribution 4.0 (cc by 4.0) international license world netball cardiac screening guidelines l bogwasi,1,2,3 mbbs, msc; dc janse van rensburg,1,4 mmed, md; g bryant,4,5 mbbs, graddipspsc; j orchard,6 mph, phd; j a drezner,7 md 1 section sports medicine, faculty of health sciences, university of pretoria, south africa 2 nyangabgwe hospital, orthopedic department, francistown, botswana 3 medical member, confederation of african football, cairo, egypt 4 world netball medical commission, manchester, uk 5 sports medicine at sydney university, the sports clinic, the university of sydney 6 centenary institute, the university of sydney, sydney, australia 7center for sports cardiology, university of washington, seattle, wa, usa corresponding author: l bogwasi (lonebogwasi@ymail.com) the health benefits of physical activity are well documented.1-2 it is known, however, that intense physical activity in the setting of underlying cardiac pathology can trigger potential catastrophic cardiac events, such as sudden cardiac arrest or death during sport.3 these cardiac events have been recorded worldwide in different sporting codes at both amateur and elite levels.3 it has led to more emphasis being placed on the preparticipation medical assessment (ppma) as a recommended practice for athletes before engaging in physical activity.3 the ppma is conducted in the pre-season or before any major competition at regional, national, and international levels.4-6 netball forms part of this cohort of exertional physical activities and as such, a world netball cardiac screening policy is of great importance. the contents of a ppma may vary based on resource availability, sports medical expertise, discretion or availability and, most importantly, the recommendation of the particular sport regulatory body. although cardiac screening is not one-hundred percent effective in preventing cardiac incidents during sporting activity,7 it aims at identifying those pathologies associated with catastrophic events when combined with physical activity. cardiac screening has been an area of focus within the sport and exercise medicine community to curb morbidity and/or mortality from sudden cardiac arrest in competitive athletes. other consequences from catastrophic incidents include the psychological trauma placed on the athletes’ family, team members, spectators, and community, along with the magnitude of attention it carries towards the sporting code, team, national and international federations and the team physicians. although tragic events are rare, they have a huge impact.8 sudden cardiac arrest is the cause of 75% of deaths during sport. 9although the precise risk in netball athletes is unknown, the incidence of sudden cardiac death in sports is reported at 0.5-2 cases in 100 000 in young competitive athletes between ages 12-35 years.3,10 with proper emergency planning, a significant proportion of the victims survive. 8 however, the 2033% that do not survive despite immediate resuscitation with an automated external defibrillator (aed),11-13 reiterates that prevention is better than cure. early identification of detectable pathologies is very important regardless of the low prevalence (0.3%) of cardiac abnormalities associated with sudden cardiac arrest or death. 14 there is a heterogeneity of causes, such as cardiomyopathies, long qt syndrome, idiopathic left ventricular hypertrophy, myocarditis and anomalous coronary arteries. hypertrophic cardiomyopathy is the most common of these and accounts for 8-36% of cardiac pathologies identified after sudden cardiac death in the athlete population.10,15 in up to 44% of athletes that suffered sudden cardiac death, no structural abnormalities are seen at post-mortem, with a proportion thought to be caused by primary electrical disorders.16 there is ongoing debate regarding standardisation or individualisation of cardiac screening tests in athlete populations concerning age, sex, family history, race, sport, and level of activity, weighed against the risks associated with the potential interventions for the cardiac conditions detected.15 cardiac screening in physical activity the basics of a cardiac screening programme entail a detailed history, physical examination and an electrocardiogram (ecg) with further tests such as an echocardiogram, cardiac magnetic resonance imaging (cmri), ambulatory or stress ecg when baseline results are unclear or abnormal. there is a continuing debate on the mandatory inclusion of a 12-lead ecg in a routine pre-participatory screening with scrutiny regarding its detection rate, availability, and the ability of the physician to provide an athlete-specific accurate interpretation. in athlete populations, the ecg detects 60% of cardiac pathologies at risk of sudden death with a low falsepositive rate (1.3%) when interpreted by experienced physicians.17 when a standardised athlete-specific ecg interpretation is applied, the sensitivity and specificity of the sudden cardiac adverse events remain an area of concern in sport. the precise risk for netball athletes is unknown but the annual incidence of sudden cardiac death in sports is reported at 0.5-2 cases in 100 000 young competitive athletes between the ages of 12-35 years. cardiac screening in the sport and exercise medicine context aims at identifying pathologies associated with catastrophic events when combined with physical activity. there is an ongoing debate relating to the standardisation of the pre-participatory medical assessment (ppma). world netball (wn) commissioned a cardiac screening policy (13 march 2022). the minimum ppma recommended by world netball is a history, physical examination, and a resting 12-lead electrocardiogram (ecg). ecgs should be interpreted in accordance with athletespecific ecg interpretation criteria. expansion of sports cardiology experience and infrastructure, in combination with universal emergency response planning for sudden cardiac arrest, is intended to safeguard athlete health and player welfare in wn. keywords: sudden cardiac death, sudden cardiac arrest, preparticipatory medical assessment s afr j sports med 2022;34:1-4. doi: 10.17159/2078-516x/2022/v34i1a13979 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13979 https://orcid.org/0000-0002-5702-7277 https://orcid.org/0000-0003-0489-6492 https://orcid.org/0000-0003-1058-6992 https://orcid.org/0000-0003-3519-9120 https://orcid.org/0000-0001-7189-5911 position statement sajsm vol. 34 no. 1 2022 2 ecg in detecting cardiac abnormalities is improved.18,19 when contemporary athlete-specific ecg standards are used by clinicians with ecg interpretation experience, approximately one in six abnormal ecgs (positive predictive value) will represent a pathologic cardiac disorder associated with sudden cardiac arrest and death.17 there are limitations in detecting cardiac pathologies when using only patient history and physical examination, as up to 80% of athletes with underlying cardiac disorders may not display symptoms.7,20,21 augmentation of the ppma with an ecg is therefore important and should be done whenever accessible by physicians capable of accurate ecg interpretation with access to cardiology resources for secondary testing of ecg abnormalities. an ecg with an abnormal finding or more than one borderline finding according to the international criteria for athlete ecg interpretation22 guides further cardiac evaluation. evidence-based recommendations the best available evidence suggests that cardiac screening does not eliminate all risk of cardiac-associated adverse events in physical activity. however, the detectable cases from cardiac screening are important to promote an environment conducive to the safe participation of the athlete.23 based on the current evidence, world netball through its medical committee developed and adopted these cardiac screening guidelines with support from two independent cardiac experts. the minimum ppma recommended by world netball is a history, physical examination and a resting 12-lead ecg. ecgs should be interpreted in accordance with athlete-specific ecg interpretation criteria (currently the international criteria).22 guidelines for member associations 1. national level  cardiac screening is recommended for all netball players aged 16 years and older. netball players that are younger than 18 years must undergo cardiac screening in the presence of an adult guardian. cardiac screening in athletes older than 35 years should shift focus to a risk assessment for atherosclerotic cardiovascular disease.  netball players should undergo cardiac screening at least three to four weeks before the start of the season, or the first major competition.  netball players should have cardiac screening annually, or at least every two years, guided by the availability of resources.  netball players with positive test results during screening need further evaluation. some players with screening abnormalities will be advised to pause playing and training until the secondary evaluation is complete. for players who have been recommended to stop playing and training due to an abnormality found on cardiac screening, the player is not to return until cleared by a specialist cardiologist. when cleared to play, the player must be followed up at the interval recommended by their cardiologist.  any player who develops cardiac symptoms during the season should seek medical evaluation and follow-up as required.  member associations are encouraged to have close contact with a qualified sports medicine physician for cardiac screenings.  member associations are encouraged to develop a cardiology infrastructure, including a referral network of cardiologists (or sports cardiologists), for evaluation of screening abnormalities and participation guidance if a cardiac disorder is identified.  member associations are encouraged to have recurring educational training regarding cardiac issues in sports, including the role and limitations of cardiac screening, and the recognition and management of sudden cardiac arrest on the field-of-play.  national associations must have a clear cardiac resuscitation plan with qualified responders and a functional aed (please write out in full when used for the first time) available before any netball game or national team training. this procedure is also encouraged at regular team training.  sudden cardiac arrest should be assumed in any athlete that collapses and is unresponsive. immediate resuscitation measures include: 1) activating the emergency medical response system, 2) cardiopulmonary resuscitation starting with chest compressions, and 3) retrieval and application of the aed as soon as possible.  interruptions in chest compressions should be minimised and aed first shock time should be less than 3 minutes after collapse. emergency preparedness also extends to the transfer to in-hospital care and post-cardiac event care and rehabilitation.  member associations must implement reporting of sudden cardiac arrest and death in sports as a recordable event and develop a clear chain of reporting to world netball through the national association. in cases of sudden death, a post-mortem is encouraged through the consent of the guardians where possible. 2. team physicians  must conduct ppma of the team during the pre-season or before the first major competition.  are encouraged to provide players with information on the benefits and limitations of cardiac screening.  are encouraged to have a background in athlete cardiac screening and, in particular, have undergone training on ecg interpretation in athletes.24 free online training modules for the international criteria are available at: https://uwsportscardiology.org/e-academy/  should form a working relationship with a local cardiologist for organising follow-up if required and management of complex cases.  must educate their athletes on cardiac issues in sports and encourage them to report symptoms.  are encouraged to have a good working relationship with their players allowing them to openly report symptoms without fear. position statement 3 sajsm vol. 34 no. 1 2022  are responsible to develop an emergency action plan for sudden cardiac arrest with the appropriate education of their coaches and staff. 3. players  are encouraged to be the custodians of their health and give correct answers during screening evaluations and report symptoms. 4. coaches  are encouraged to fully support their medical team and be trained in cardiopulmonary resuscitation (cpr) and the use of an aed.  must have a good relationship allowing players to confide in them without fear. figure 1 summarises the recommendations of the world netball cardiac screening policy. conclusion medical professionals and teams must ensure cardiac screening of their athletes. although this does not eliminate the risks of cardiac-related adverse events, it ensures that detectable cases from cardiac screening are worked up and managed accordingly. while this cardiac screening policy was written explicitly for world netball, the guidelines apply to any sport to promote an environment conducive to the safe participation of the athlete. disclaimer: this document was compiled to guide cardiac screening in the netball population. it remains the responsibility of the team medical personnel and management to ensure the guide is adhered to and an emergency plan is created for any cardiac-related adverse activities. fig. 1. cardiac screening algorithm. aed, automated external defibrillator; ecg, electrocardiogram; scs, sudden cardiac arrest; scd, sudden cardiac death; cpr, cardiopulmonary resuscitation position statement sajsm vol. 34 no. 1 2022 4 conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. approved by: the 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performance of the american heart association (aha) 14‐point evaluation versus electrocardiography for the cardiovascular screening of high school athletes: a prospective study. j am heart assoc 2019; 8(14):e012235. doi: 10.1161/jaha.119.012235. pmid: 31286819 22. drezner ja, sharma s, baggish a, et al. international criteria for electrocardiographic interpretation in athletes: consensus statement. br j sports med 2017; 51(9):704-731.doi: 10.1136/bjsports-2016-097331. pmid: 28258178 23. malhotra a, dhutia h, finocchiaro g, et al. outcomes of cardiac screening in adolescent soccer players. n engl j med 2018; 379(6):524-534.doi: 10.1056/nejmoa1714719. pmid: 30089062 24. drezner j [internet] ecg interpretation in athletes. bmj learning [2020]. available from: https://learning.bmj.com/learning/courseintro/.html?courseid=10042239 https://www.world.rugby/news/79919?lang=en 108 sajsm vol. 27 no. 4 2015 original research different tissue type categories of overuse injuries to cricket fast bowlers have different severity and incidence which varies with age p blanch,3,4 m app sc; j orchard,2 phd; a kountouris,1 phd; k sims,1 phd; d beakley,1 m sports physio 1 cricket australia, brisbane, australia 2 school of public health, university of sydney, australia 3 high performance department, essendon football club, melrose dve, tullamarine, australia 4 school of allied health sciences, griffith university, gold coast, australia corresponding author: k sims (kevin.sims@cricket.com.au) background. cricket fast bowlers have a high incidence of injury and have been the subject of previous research investigating the effects of previous injury, workload and technique. bone stress injuries are of particular concern as they lead to prolonged absences from the game, with younger bowlers appearing to be at particular risk. objectives. to investigate the variation in severity and incidence of injury to different tissue types in fast bowlers and ascertain whether age is a significant risk factor for these injuries. methods. a retrospective analysis of match bowling exposure in 215 separate fast bowlers over a 14-year period was undertaken. this information was amalgamated with injury surveillance data providing information on the incidence, location, tissue type and severity of injury. age of the bowler was determined and the bowlers were stratified into five age groups to determine the influence of age on the injury variables. results. younger bowlers (less than 22 years old) were 3.7-6.7 times more likely to suffer a bony injury than all the other age groups. older bowlers (greater than 31 years old) were 2.2-2.7 times more likely to suffer a tendon injury than the 3 youngest groups. conclusion. this study has demonstrated that younger age is a considerable risk factor in the development of bone stress injuries in cricket fast bowlers. in addition there appears to be a higher incidence of tendon injuries in older fast bowlers although this may be explained by the current classification system of joint impingement as a tendon injury. keywords. bone, tendon, sports injuries s afr j sports med 2015;27(4):108-113. doi:10.17159/2078-516x/2015/ v27i4a436 injury to fast bowlers in cricket is one of the most significant of the sport’s ongoing medical challenges. three major risk factors have been identified in the literature. firstly, the effect of previous injury on subsequent injury is well established across a number of sports.[1,2] secondly, workload and workload variation have been identified as major risk factors for fast bowling injury. both high and low overall bowling workloads have been identified as an injury risk factor.[3] while a high workload would seem intuitive and it has been demonstrated that bowling more than 50 overs in a match or more than 30 overs in the last innings of a match leads to an increase in injury likelihood for the subsequent month,[4] the reason why a low workload is dangerous is less clear. recent research suggests that low workloads are a risk factor because they are related to subsequent rapid increases (spikes) in the bowling load, which is also an identified injury risk factor.[5] the workload studies[4,5] tend to group all injuries together with the definition for an injury being the cessation of the current match and/or loss of subsequent competition. this places all injuries on a par and negates any measure of severity. however, this is not the case with lumbar stress fractures[6–9] which lead to longer periods out of the game. bowling technique is the final of the three identified risk factors in fast bowling injuries, with biomechanical research indicating a link between excessive shoulder counter-rotation and lumbar spine stress fractures.[8,10] biomechanical research is often conducted on adolescent or young fast bowlers[6,11] or does not clearly identify the demographics of the injured vs. non-injured groups.[10] so it is unclear whether the risk factor of poor technique (excessive shoulder counterrotation) continues into the older age groups.[12] in a previous paper these authors demonstrated that different injuries to cricket fast bowlers classified by the structure injured (bone, muscle, tendon, joint) had different types of loading histories that were either protective or risky.[13] a contrasting finding was that a high medium-term load was protective of tendon injuries but a risk factor for bony injuries.[13] in this previous work the authors excluded the variable of age as it was found to be strongly correlated to career workload. due to the exclusion of age in this previous investigation, the purpose of this study was to determine the effect of age on the variation in severity and incidence of injury to different tissue types in cricket fast bowlers. materials and methods cricket australia conducts an annual ongoing injury survey recording injuries in contracted first-class players. methods for this survey have been described previously.[14] the methods used for cricket australia injury surveillance are non-interventional, conform to the code of ethics of the world medical association (declaration of helsinki) and have been approved by the cricket australia sports science sports medicine advisory group. this study amalgamated the injury data files from the previously mentioned injury surveillance program and match workload data from official scorecards (available online at http://www.espncricinfo. com/ci/engine/series/index.html) of first class (long form) and list a (short form) over 14 seasons from 1998-99 to 2011-12, inclusive. injury definition, diagnosis and severity in 2005, cricket researchers published international injury consensus definitions for the sport and the methods of this survey adhere to the international definitions.[15] the definition of a cricket injury is one that either: (1) prevents a player from being fully available for selection in a major match (which is either a first-class, two-innings per team, or limited overs, which is one-innings per team) or (2) during a major match, rendering a player unable to bat, bowl or wicket-keep when required by either the rules or the team’s captain. mailto:kevin.sims@cricket.com.au http://dx.doi.org/10.17159/2078-516x/2015/v27i4a436 http://dx.doi.org/10.17159/2078-516x/2015/v27i4a436 http://www.espncricinfo.com/ci/engine/series/index.html http://www.espncricinfo.com/ci/engine/series/index.html sajsm vol. 27 no. 4 2015 109 severity of the injury was determined by the cumulative numbers of matches missed which was calculated for each injury until the player returned to play. this study concerns fast bowling injuries only and therefore includes a dataset of injuries in fast bowlers sustained either with an acute non-contact bowling mechanism or a gradual onset bowling mechanism. injuries which were sustained either when batting or fielding were not considered as part of this study. all injuries were coded using the osics 9 system.[16] the second character of the injury diagnosis was used to subcategorise the injury into muscle, bone stress, tendon or joint injuries. further analysis of bone stress injuries were based on body part. analysis age age was calculated on the first day of a match, thus if a player’s birthday occurred during a match the exposure of that match was included in the lower age bracket. age was then characterised into five groups: • <22 years old (y.o.) • 22-25 y.o. • 25-28 y.o. • 28-31 y.o. • >31 y.o. the age brackets were selected to have as many even categories as possible but still maintain sufficient numbers for analysis. exposure exposure was measured by total number of overs bowled in short and long form matches by each of the age groups over the 14 seasons. proportion of long form cricket and overs bowled per match type was also calculated, as was the average overs per match. severity for each injury the number of matches lost before return to play was used as a measure of injury severity. two-way anova a two-way anova with ‘matches lost’ as the dependant variable and ‘age group’ and ‘injury type’ as fixed factors was run in spss (version 19). incidence the number of injuries per 1000 overs of exposure was calculated across the age groups. injury cost combining the elements of severity and incidence as a measure of injury cost the authors calculated the number of matches missed per 1 000 overs of exposure for the different age groups and injury types. results the 14 season data allowed the authors to follow 215  individual bowlers playing in 1 588 separate matches for 4 014 long form and 6 321 short form player matches. over that time fast bowlers suffered a total of 563 bowling-related injuries with 62 joint injuries, 101 bone injuries, 292 muscle injuries and 108 tendon injuries that conformed to the authors’ injury definition. table 1. bowling exposure of different age grouped fast bowlers over 14 seasons age (years) overs bowled over 14 seasons matches played over 14 seasons average overs per match (sd) long form (% of population) short form (% of population) total overs (% of population) long form short form %long form long form short form <22 10 748 (9.0) 4 118 (9.3) 14 866 (9.0) 395 647 37.9 27.2 (11) 6.4 (3) 22-25 25 596 (21.3) 9 232 (20.7) 34 828 (21.2) 877 1 287 40.5 29.2 (11) 7.2 (3) 25-28 36 900 (30.7) 13 077 (29.4) 49 977 (30.4) 1 217 1 835 39.9 30.3 (12) 7.1 (3) 28-31 27 012 (22.5) 11 195 (25.1) 38 207 (23.2) 879 1 543 36.3 30.7 (12) 7.3 (3) >31 19 794 (16.5) 6 895 (16.5) 26 689 (16.2) 646 1 009 39.0 30.6 (13) 6.8 (3) total 120 050 (100%) 44 517 (100%) 164 567 (100%) table 1 demonstrates that there are some differences in the proportional bowling load of the different age groups across matches but not within matches. the <22 years age group bowl around 9% of the overall deliveries, 22-25 years group 21%, 25-28 years group 30%, 28-31 years group 23.5% and the >31 years group 16.5%. the proportional relationship of the age groups does not change much from long form to short form cricket. interestingly, about 40% (36.3-40.5%) of the overs bowled come from long form cricket, and this is also consistent across the age groups. also showing strong consistency across the age groups is the average overs per match, especially in the long form of the game, with the range only being between 27-31 overs per match. so while younger players did not play as many matches the requirement for them to bowl once in a match was similar to other groups. 110 sajsm vol. 27 no. 4 2015 table 2 clearly illustrates that bone injuries cost considerably more lost matches than the other injury types. in the two-way anova injury type was a significant factor (p<0.05) for lost playing time. post-hoc analysis suggests that bone injuries were significantly (p<0.05) more costly than the other three subgroups (mean difference range 5.8-9 matches lost). tendon injuries were also significantly more costly than muscle injuries (p<0.05, mean difference 3.2 matches). age did not appear as a significant factor (p=0.35) in the severity (matches lost) of the different pathologies i.e. a muscle injury resulted in as many lost matches for all age groups. the interaction between the two factors fell just above the 0.05 level (p=0.055) with the largest difference being between the <22 and 22-25 group that demonstrated significance in the post-hoc testing (p=0.023, mean difference 2.8 matches with the younger players taking longer on average to recover from an injury). while the severity of the different injury types in table 3 did not vary much across the age groups, there are some quite marked differences in the incidence of the injuries across different ages. younger (<22 y.o.) and older (>31 y.o.) are 1.8-3.7 times more likely to suffer a joint injury than the other age groups. younger bowlers are 3.7-6.7  times more likely to suffer a bony injury than all the other age groups. younger bowlers are slightly more likely (1.4-1.6  times) to suffer a muscle injury. the incidence of tendon injuries is quite similar across the three youngest age groups and gradually increases in the 28-31 y.o. group, and is at the highest in the >31 y.o. group. the >31 y.o. group are 2.2-2.7  times more likely to suffer a tendon injury than the three youngest groups. the combination of severity and incidence depicted in figure 1 and table 4 respectively provides a much better overview of the cost of the different injuries across the different age groups. overall injury cost is clearly higher in younger bowlers, with this cost decreasing and plateauing out as they get older (22-31 y.o) and then increasing again as they go past 31 y.o. the bone injuries to young players is by far the most costly injury. this is driven not necessarily by the severity but by the much greater incidence of these injuries. these data also demonstrate the escalating cost of tendon injuries for older bowlers. this, associated with a small increase in the cost of joint injuries, makes the older group the second most costly group for injury. table 2. the descriptive statistics of the different age groups and injury types used in the two‑way anova average matches lost per injury type joint bone muscle tendon age (years) mean (sd) n mean (sd) n mean (sd) n mean (sd) n <22 4.6 (3.9) 9 13.5 (11.0) 31 5.0 (6.2) 38 4.5 (3.4) 8 22-25 5.4 (5.7) 10 11.6 (10.6) 19 3.8 (2.8) 57 4.1 (4.0) 17 25-28 5.6 (5.8) 17 11.1 (10.4) 28 4.2 (3.6) 88 9.1 (15.2) 22 28-31 4.1 (2.5) 7 18.9 (17.8) 12 4.0 (4.8) 61 4.9 (5.6) 29 >31 6.1 (11.5) 18 14.1 (10.5) 11 3.8 (3.2) 48 10.7 (13.3) 32 all 5.3 (7.3) 61 13.1 (11.7) 101 4.1 (4.1) 292 7.3 (11.6) 108 table 3. the incidence of the different injury types per 1 000 overs at different age groups injuries per 1 000 overs age (years) joint bone muscle tendon <22 0.61 2.09 2.56 0.54 22-25 0.29 0.55 1.64 0.49 25-28 0.34 0.56 1.76 0.44 28-31 0.18 0.31 1.60 0.76 >31 0.67 0.41 1.80 1.20 fig. 1. the number of matches lost per 1 000 overs bowled by different age groups and different injury type table 4. the number of matches lost per 1 000 overs bowled by different age groups and different injury types plus the total matches lost per age group matches lost per 1 000 overs bowled age (years) joint bone muscle tendon total <22 2.8 28.1 12.8 2.4 46.1 22-25 1.6 6.1 6.3 2.0 15.9 25-28 1.9 6.2 7.4 4.0 19.6 28-31 0.8 5.9 6.4 3.7 16.9 >31 4.1 5.8 6.8 12.8 29.5 sajsm vol. 27 no. 4 2015 111 table 5. the number of bone stress injuries at different body areas by different age groups* number of bone injuries in different body regions age (years) thorax foot lumbar lower leg <22 2 3 17 6 22-25 2 2 10 2 25-28 3 6 14 3 28-31 3 1 7 0 >31 1 4 4 1 * 91 of 101 bone injuries are classified in these areas; others have been excluded for brevity table 6. the number of muscle injuries at different body areas by different age groups* number of muscle injuries in different body regions age (years) lumbar/trunk hip/groin thigh lower leg shoulder <22 20 4 9 2 1 22-25 23 3 20 1 2 25-28 28 7 39 11 1 28-31 18 6 29 13 2 >31 8 8 20 12 1 * 280 of 292 muscle injuries occurred in the above areas; others have been excluded for brevity table 7. the number of tendon injuries at different body areas by different age groups* number of muscle injuries in different body regions age (years) ankle hamstring origin adductor knee shoulder <22 1 0 0 2 0 22-25 4 1 4 2 2 25-28 4 4 5 3 4 28-31 10 1 5 7 4 >31 14 1 2 6 6 * 92 of 102 tendon injuries are classified in these areas; others have been excluded for brevity discussion the results of this study illustrate that bony injuries have much greater severity than other types of overuse injuries in cricket fast bowlers. this, combined with a much greater incidence in younger bowlers, highlights that this is of particular importance in that group. while these two statements may not seem remarkable given the amount of research that has been done on bone injuries, especially in young fast bowlers, these authors believe this is the first study to clearly identify younger age as a risk factor in cricket fast bowlers and demonstrate the magnitude of that risk. younger age as a risk factor for stress fractures has been previously shown in the israeli military.[17] their findings showed that as age increased from 17 years through to 26 years, bony injury risk decreased by 28% per year. the findings in this present study are consistent with this trend, although it is difficult to compare the two populations, with only 3.3% (26 out of 796) of the military population over the age of 19 years, whereas this study’s population was comprised of athletes of whom 98% were above the age of 19 years. also, the type of injury suffered by the two populations is quite different. the israeli military recruits suffered predominately from tibial stress fractures, followed by femur and then metatarsal fractures. in this study’s fast bowling group the most common bony stress injury was to the lumbar spine, with the foot (tarsal and metatarsal combined) a distant second, the shank (tibia and fibula combined) less common and finally, the thorax (vertebrae, ribs and sternum combined). there were no reported femoral stress fractures (see table 5). the large number of lumbar spine bone stress injuries is not surprising as the incidence of these injuries in cricket fast bowlers has been reported to be between 11-55%[7,8,18] and is considerably higher than the normal population.[19] what this study demonstrates is that those bone stress injuries are clearly related to age. this is consistent with the first injury surveillance work in south african cricket which reported that all the fast bowlers who developed bone stress injuries during their three year injury surveillance period were under the age of 24 years.[20] the higher incidence of bone injuries in younger athletes may be related to bone development and maturity. key aspects of bone development, such as peak bone mass, bone mineral density (bmd) and bone mineral content (bmc), are age and site specific.[21] more specifically, the major increases in bmd and bmc in the lower limb bones occur between puberty and 18 years old, whilst in the lumbar spine there are continuing increases in bmd, bmc, vertebral height and vertebral width until 25 years old.[22] these aspects of bone structure and geometry are key determinants of bone strength and therefore key to bone stress fracture risk.[21] it has been shown that reduced bmd and bmc are risk factors for developing stress fractures in female athletes and military recruits;[23,24] however, the link with male athletes is less clear. male military recruits with lower bmc are at greater risk for developing stress fractures but despite the bmd in the hip and spine being lower (3-4%) in the stress fracture group the relationship with injury was not strong.[21] in the current study the higher incidence of bone injuries in younger fast bowlers could be explained by skeletal immaturity, particularly as there were a high number of bone injuries in the lumbar spine that matures later than the long bones of the lower limb. skeletal immaturity in combination with high bowling loads is therefore the likely reason that younger fast bowlers are more vulnerable to bone injuries. while in our analysis younger bowlers make up a smaller proportion of the total overs bowled within a season once they are in a match they bowled as much as their older counterparts. this would suggest that young fast bowlers 112 sajsm vol. 27 no. 4 2015 are more susceptible than older bowlers to bone stress injury with similar within match bowling loads. figure 1 and table 4 highlight that younger fast bowlers missed considerably more matches per 1 000 overs bowled due to bone injury compared to other age groups and injury types. compared to other age groups, younger bowlers also have a greater issue with muscle injuries with a slightly higher severity (5.0 matches lost per injury) and a slightly higher incidence (2.56 per 1 000 overs, see table 3). this led to 12.8 matches lost per 1 000 overs bowled (see table 4) which is nearly twice that of the other age groups. the higher severity is most likely due to the type of muscle injury suffered by younger players. lumbar and trunk injuries represented over 55% of the muscle injuries reported by younger bowlers. these were predominately (93%) side strains (a tear of the attachment of the internal or external oblique muscle off the lower ribs) and this proportion of lumbar/ trunk strains from total muscle injuries dropped off as the bowling groups became older (22-25 y.o. 46%, 25-28 y.o. 33%, 28-31 y.o. 30%, >31 y.o. 14%) (see table 6). anecdotally, side strains have been one of the more recalcitrant muscle injuries suffered by fast bowlers and are predominately described in cricket fast bowlers.[25] the higher incidence of side strains in younger bowlers with a subsequent decline in incidence with age may reflect a relative weakness of the attachment of the abdominal muscles to the ribs in younger bowlers. while joint injuries were the least expensive group of injuries for time loss there were some variations across the ages, with the youngest and oldest age group having an approximately 2-4 times higher incidence rate of the other age groups (see table 3). with only 62 joint injuries spread over five age groups and five or more body areas the reason for this variation is unclear. over 50% (34) of the joint injuries were allocated to the lumbar spine with the others spread between the ankle, foot, elbow and knee. this is likely due to the methodological inclusion criteria in this study – “a dataset of injuries in fast bowlers sustained either with an acute non-contact bowling mechanism or a gradual onset bowling mechanism”. this excludes the acute joint injuries, such as sprains from falls in the field, which often make up the predominate numbers of joint injuries in surveys. there is also perhaps a bias to attribute non-specific low back pain to a lumbar joint origin. while it is clear that younger bowlers are the most at risk for losing game time due to injury (46.1 matches per 1 000 overs bowled), older bowlers (>31 y.o.) are particularly vulnerable to tendon injuries. the incidence of tendon injuries remains quite low and stable at the younger three age groups (0.44-0.54 injuries per 1 000 overs) but starts to increase in the 28-31 age group (0.76 injuries per 1 000 overs) and increases again in the >31 age group (1.2 injuries per 1 000 overs) (see table 3). the concept of increasing age being a risk factor for tendinopathy has previously been discussed in clinical commentaries,[26] although a recent study on patella tendinopathy in elite soccer players did not support this.[27] at present it is unclear why there is a difference between clinical perception and published epidemiological evidence. in the current study the differences in the severity of tendon injuries are clouded by large variability in the number of games missed. there is also a problem with what is classified as a tendon injury. the increasing incidence of tendon injuries is predominantly driven by injuries to the ankle, although the knee (including quads tendon, patella tendon, hamstring insertion and iliotibial band) and the shoulder (mostly rotator cuff ) are also represented (see table 7). while the ankle distribution includes achilles tendon injuries, 26 of these 33 (79%) injuries were diagnosed by the medical staff as ankle impingement, but under the osics 9 system these were classified as tendon injuries. so the escalating incidence of tendon injuries can be explained by escalating ankle impingement. this is perhaps a limitation of the current coding system and needs to be considered in the future. conclusion in conclusion, this study has demonstrated that younger age is a considerable risk factor in the development of bone stress injuries in cricket fast bowlers. the lumbar spine is 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[http://dx.doi.org/10.1016/j. bone.2013.04.011] 22. walsh js, henry ym, fatayerji d, et al. lumbar spine peak bone mass and bone turnover in men and women: a longitudinal study. osteoporos int 2009;20(3):355-362. [http://dx.doi.org/10.1007/s00198-008-0672-5] 23. loud kj, micheli lj, bristol s, et al. family history predicts stress fracture in active female adolescents. pediatrics 2007;120(2):e364-372. [http://dx.doi.org/10.1542/ peds.2006-2145] [3200550] 24. pouilles jm, bernard j, tremollieres f, et al. femoral bone-density in young male adults with stress-fractures. bone 1989;10(2):105-108. [http://dx.doi.org/10.1016.87563282(89)90006-9] 25. obaid h, nealon a, connell d. sonographic appearance of side strain injury. ajr am j roentgenol 2008;191(6):w264-w267. [http://dx.doi.org/10.2214/ajr.07.3381] 26. rees j, wilson a, wolman r current concepts in the management of tendon disorders. rheumatology (oxford) 2006;45(5):508-521. [http://dx.doi.org/10.1093/ rheumatology/kel046] [16490749] 27. hägglund m, zwerver j, ekstrand j. epidemiology of patellar tendinopathy in elite male soccer players. am j sports med 2011;39(9):1906-1911. [http://dx.doi. org/10.1177/0363546511408877] http://dx.doi.org/10.1016/j.sams.2006.05.001 http://dx.doi.org/10.1016/j.sams.2006.05.001 http://dx.doi.org/10.1136/bjsm.2004.012732 http://dx.doi.org/10.1136/bjsm.2004.012732 http://dx.doi.org/10.2147/oajsm.s7715 http://dx.doi.org/10.2147/oajsm.s7715 http://dx.doi.org/10.1097/01.brs.0000061992.98108.a0 http://dx.doi.org/10.1136/bjsm.37.3.250 http://dx.doi.org/10.1136/bjsm.37.3.250 http://dx.doi.org/10.1016/j.bone.2013.04.011 http://dx.doi.org/10.1016/j.bone.2013.04.011 http://dx.doi.org/10.1007/s00198-008-0672-5 http://dx.doi.org/10.1542/peds.2006-2145 http://dx.doi.org/10.1542/peds.2006-2145 http://dx.doi.org/10.1016.8756-3282(89)90006-9 http://dx.doi.org/10.2214/ajr.07.3381 http://dx.doi.org/10.1093/rheumatology/kel046 http://dx.doi.org/10.1093/rheumatology/kel046 http://dx.doi.org/10.1177/0363546511408877 http://dx.doi.org/10.1177/0363546511408877 obituary 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license dr richard de villiers – a tribute saturday, 9th july 2022 saw the sudden passing of dr richard de villiers, a giant in the south african musculoskeletal imaging community after he suffered a heart attack whilst cycling in the waterberg. i first met richard while training and competing in triathlons in cape town in the early nineties after he completed his internship at addington hospital in durban. he was a fierce competitor who represented western province and south africa as an age-group triathlete. i recall training with him in the pool at the durbanville virgin active club and on the bellville track where we pushed each other deep into the red zone. after returning from a year-long sports medicine fellowship in wellington, new zealand, at the end of 1994 i was training with richard and told him how the radiologists in the wellington hospital were in touch with the nuances of sports medicine. i told him about jock anderson, an australian and internationally renowned sports radiologist and connected him with jock. richard, as was his fearless nature jumped at the opportunity and met and endeared himself to jock anderson. he learnt from the guru and his interactive approach to the multidisciplinary nature of sports medicine. back home in south africa richard was instrumental in getting jock anderson to visit and lecture in south africa on several occasions. together in 1995, we initiated multidisciplinary meetings at tygerberg hospital. richard was a pioneer in the growth of sports imaging in south africa instrumental in establishing the south african musculoskeletal imaging group (samsig) in 2005. richard matriculated in 1984 from paarl gymnasium. he completed his medical degree at stellenbosch university in 1990 where he also trained as a radiology registrar. after qualifying as a radiologist in 1997 he underwent sub-specialist training in qatar and the uk and was registered as a specialist in both countries. richard published numerous peer-reviewed articles, at last count 43. he organized and lectured at numerous workshops and congresses locally and internationally. he was on the editorial board of the south african journal of sports medicine. richard was instrumental in establishing radiological services within the sports science institute of south africa in newlands in 2003 and likewise in his beloved town of stellenbosch. he was instrumental in raising the bar for radiological services to athletes across all disciplines and ages at local, provincial, national and international levels. through his love of cycling, he actively assisted in developing mountain bike trails in and around stellenbosch. watching richard's career flourish and his enjoyment of his work and enthusiastic approach inspired me to re-specialize in 2002 as a radiologist. richard was always supportive and encouraging. in the weeks before his passing, we had been in regular contact regarding his new ventures including the musculoskeletal fellowship program initiated at groote schuur hospital this year. as a member of the international skeletal society and the chairman of the south african musculoskeletal imaging group, he will be sorely missed at the local and international levels. on behalf of the south african sports medicine association, i would like to extend our sincerest condolences to his wife, marie-louise, as well as his parents and other family members. i would also like to thank richard for his pioneering contribution to sports medicine in south africa and for his friendship and support to all who had the privilege of working with him. personally, he will be sorely missed as a supportive colleague, friend and one helluva tough competitor. jean-claude koenig radiologist wedderburn-maxwell and partners durban, kwazulu-natal, south africa s afr j sports med 2022;34:1. doi: 10.17159/2078-516x/2022/v34i1a14630 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a14630 92 sajsm vol. 27 no. 4 2015 editorial a skilled writer should be able to explain a complex topic to a reader who is not familiar with that topic. however, that is easier said than done as every branch of science embodies its own set of terms and words. anyone working in a specialised area has to learn the set of terms associated with that topic, and use the appropriate terms and words to communicate with their colleagues. failure to do so creates a barrier to entry; it makes it difficult to communicate and understand what others have said about the discipline. in the early phases of a new discipline, the terminology may be used slightly differently. however, as the discipline or area of research evolves, the words and definitions used to describe the nuances of that area become standardised. this reduces the risk of ambiguity and results in the communication on the specialised topic reaching a deeper level. with well-defined terminology, the results of studies can be compared and the knowledge in that area develops at a more rapid rate. there are many examples in sport and exercise medicine research where this has happened. consider cricket research, where the lack of consistent definitions for injury in the sport resulted in the research on injuries plateauing. the calculation of exposure to injury varied. the sticking point was that data from different studies could not be compared. this prompted collaboration between cricket authorities in australia, the united kingdom, south africa, new zealand, the west indies, and india to standardize the nomenclature used in cricket research. this resulted in a paper, which was widely circulated.[1] the consensus paper went into detail about the definitions for injury, injury recovery and injury recurrence in cricket. factors associated with exposure calculations were discussed. the paper even had worked examples showing how exposure should be calculated and a check list of information that should be collected by an injury surveillance system. it is no surprise that the quality of research into cricket injuries was transformed from being largely descriptive to more mechanistic and problem solving. this consensus paper on terminology made such an impact that it is unlikely that research will get published in high impact journals if the guidelines outlined in this paper are not adopted. the example set by cricket was followed by soccer[2] and then rugby[3]. both documents go into detail about the definitions of injury and factors to consider in calculating exposure in the respective sports. this results in studies on the incidence of injury being expressed in a comparable way. as with the research in cricket, the quality of research in soccer and cricket has increased exponentially. another example occurred in 2006 when the european college of sport science (ecss) published its consensus statement on overtraining.[4] this statement was prompted by the many studies that were attempting to address the consequences of overtraining, but the knowledge in the area was not progressing as it should have, because the scientists were using different terms to describe the condition. this made it difficult to compare studies. the document published by the ecss was updated seven years later when the american college of sports medicine were invited to contribute.[5] this has resulted in a set of clear descriptions and working definitions for terms in this area of research. the attempt to improve and define terms in sport and exercise medicine research continues. recently a paper was published which focussed on athlete proficiency.[6] this paper provided clear definitions for athlete proficiency so that athletes can be correctly ranked into categories, instead of being loosely described as “elite” or “high level”. this refining of definitions will assist researchers around the world to describe their athletes similarly; a consequence will be better quality science. an editorial has also drawn attention to the need for clear definitions and has proposed definitions for an “athlete”, age group classifications (i.e. young athletes; 12-17 years old, adult athletes; 18-35 years old, and master athletes; 35-60 years old), and level of performance.[7] the definitions they provide are crisp and clear and easily implementable. the establishment of definitions and methodology, and reporting standards should be adopted more widely as this contributes to better quality research. this is something that the reviewers of papers submitted to the south african journal of sports medicine are going to be asked to be vigilant about, so that we can make a positive contribution to the quality of the science in sport and exercise medicine. mike lambert editor-in-chief s afr j sports med 2015;27(4):92. references 1. orchard j, newman d, stretch r, frost w, mansingh a, leipus a. methods for injury surveillance in international cricket. j sci med sport 2005;8(1):1-14. [http:// dx.doi.org/10.1016/s1440-2440(05)80019-2] 2. fuller c, ekstrand j, junge a, andersen t, bahr r, dvorak j, et al. consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries. scand j med sci sports 2006;16(2):83-92. [http://dx.doi. org/10.1111/j.1600-0838.2006.00528.x] pmid:16533346. 3. fuller cw, molloy mg, bagate c, bahr r, brooks jhm, donson h, et al. consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union. br j sports med 2007;41(5):328-31. [http://dx.doi.org/10.1136/ bjsm.2006.033282] pmid: 17452684. 4. meeusen r, duclos m, geeson m, rietjens g, steinacker j, urhausen a. prevention, diagnosis and treatment of the overtraining syndrome. eur j sport sci 2006;6(1):14. [http://dx.doi.org/10.1080/17461390600617717] 5. meeusen r, duclos m, foster c, fry a, gleeson m, nieman d, et al. prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the european college of sport science and the american college of sports medicine. med sci sports 2013;45(1):186-205. [http://dx.doi.org/10.1080/17461391. 2012.730061] 6. swann c, moran a, piggott d. defining elite athletes: issues in the study of expert performance in sport psychology. psychology of sport and exercise. elsevier ltd; 2015;16(1):3-14. [http://dx.doi.org/10.1016/j.psychsport.2014.07.004] 7. araújo cgs, scharhag j. athlete: a working definition for medical and health sciences research. scand j med sci sports 2016;26(1):4-7. [http://dx.doi.org/10.1111/ sms.12632] pmid: 26750158. terminology and nomenclature in sport and exercise medicine http://dx.doi.org/10.1016/s1440-2440(05)80019-2 http://dx.doi.org/10.1016/s1440-2440(05)80019-2 http://dx.doi.org/10.1111/j.1600-0838.2006.00528.x http://dx.doi.org/10.1111/j.1600-0838.2006.00528.x http://dx.doi.org/10.1136/bjsm.2006.033282 http://dx.doi.org/10.1136/bjsm.2006.033282 http://dx.doi.org/10.1080/17461390600617717 http://dx.doi.org/10.1080/17461391.2012.730061 http://dx.doi.org/10.1080/17461391.2012.730061 http://dx.doi.org/10.1016/j.psychsport.2014.07.004 http://dx.doi.org/10.1111/sms.12632 http://dx.doi.org/10.1111/sms.12632 jsm0404pg000ed. sports medicine vol 16 no.1 2004 25 introduction the shoulder complex consists of 5 articulations, the glenohumeral, sternoclavicular, coracoclavicular, acromioclavicular and scapulothoracic joints, making it the most complex joint in the human body.1,10,15 one of the most important joints used in shoulder movements is the glenohumeral joint, which lacks bony stability and sacrifices the stability for increased mobility.1.7,13 stability in the glenohumeral joint is provided by the glenohumeral ligaments, glenoid labrum, shoulder capsule and by the rotator cuff muscles. the external rotator strength has been reported to be around 65% of internal rotator strength.17 during bowling in cricket, the internal shoulder rotators are involved in the acceleration phase of the arm through concentric contractions, while the external rotators are involved during the deceleration phase.4 the nature of fast bowling requires the arm to be rotated at around 60000.s-1, placing great demands on the shoulder's integrity.7 in addition to the technical skills required to perform, cricketers also need to possess a high level of fitness, thus making them susceptible to overuse injuries as a result of repetitive training.5 the upper extremities account for 25% and 22% of injuries in schoolboy19 and provincial20 cricket players, respectively. however, fast bowlers have a high incidence of shoulder injuries, with fast bowlers sustaining 42% of the upper extremity injuries to cricketers.5 injuries in fast bowlers may be caused by a number of factors, such as postural defects, poor bowling technique, inadequate physical or physiological attributes, as well as high physical demands.19 further, during a match many bowlers are placed to field in the outfield and thus have a tendency to develop ‘thrower's arm’ and other injuries.19 fast bowlers with a front-on bowling action are more susceptible to an injury of the shoulder.10 the presence of an imbalance between the agonist and antagonist groups is one of the major risk factors for develoriginal research article shoulder injuries in provincial male fast bowlers — predisposing factors k d aginsky1 (ba (hons) biokinetics)1 l lategan1 (dphil)1 r a stretch2 (dphil)2 1rand afrikaans university, johannesburg 2sport bureau, university of port elizabeth correspondence: r a stretch university of port elizabeth po box 1600 port elizabeth tel: 041-504 2584 fax: 041-583 2605 e-mail: richard.stretch@upe.ac.za abstract objectives. to investigate the relationship between shoulder flexibility and isokinetic strength as possible factors that may predispose provincial fast bowlers to shoulder injuries. design. twenty-one players, 12 of whom had no history of shoulder injuries and 9 of whom had experienced a shoulder injury to the bowling arm, were assessed for shoulder strength using a cybex norm isokinetic dynamometer. absolute and relative peak torque measures were obtained at isokinetic speeds of 90°/s and 180°/s, with both concentric and eccentric contractions performed. shoulder flexibility was tested using a leighton flexometer in both internal and external shoulder rotation. the players were classified into a front-on (n = 7), semi front-on (n = 7) or side-on (n = 7) bowling action from video footage recorded after a bowling trial in the nets. results. shoulder injuries were more common in fast bowlers with a front-on action (n = 5) than the bowlers with a side-on (n = 2) or semi front-on (n = 2) action. sixteen of the 21 fast bowlers showed low stability ratios compared with gravity corrected functional ratios, indicating an imbalance and the presence of possible dysfunction. the injured group of fast bowlers showed higher concentric weight-normalised torque values for internal rotation at the higher velocity (180°/s) (65.20 ± 10.03 vs. 45.91 ± 10.26 nm.kg-1 p < 0.009: injured vs. uninjured), which would suggest greater instability when compared with the uninjured players. this imbalance could indicate the presence of a predisposition to impingement syndrome in the injured subjects. there was an increase in the external rotation ranges of movement for both groups, indicating a degree of hypermobility in both groups. the results indicate that the presence of possible dysfunction in the shoulder rotators, combined with a front-on bowling action and external rotation hypermobility, are possible predisposing factors for chronic shoulder injuries in cricket fast bowlers. oping shoulder injuries such as dislocation and impingement,16 with deficiency in the external rotator strength possibly resulting in an injury.7 thus, the aim of the study was to investigate the relationship between shoulder flexibility and isokinetic strength as possible factors predisposing a male provincial fast bowler to shoulder injuries. the findings would assist in a better understanding of the risk factors for shoulder injury in an elite fast bowler, thus suggesting methods for reducing the incidence of injury and contributing to a prolonged career with fewer shoulder problems. methods the subjects consisted of 21 male right-arm fast bowlers who had all represented their province at either under-19, provincial academy, under-23, provincial b or provincial a level. their age ranged from 17 to 36 years, with a mean age of 22.4 years. the subjects were randomly chosen from those who were within travelling distance of the test centre. prior to testing the test protocol was explained to each subject, the informed consent form was signed, biographical data, which included personal information, level of participation, training schedules, injury history specifically relating to the shoulder, and body composition and somatotype data, were obtained. the subjects were then instructed to warm up for 5 minutes on a rowing ergometer and to stretch their shoulder complex before being tested isokinetically. isokinetic shoulder testing was performed on the cybex norm isokinetic dynamometer (cybex international, inc., lumex inc., chattanooga, usa). each subject was positioned on the cybex to assess the internal and external shoulder rotation of the bowling arm, according to the manufacturers' guidelines. the arm was abducted at 90° with 90° of elbow flexion and secured by a velcro strap in a vshaped padded trough attached to the lever arm base. the lever arm handle was then brought to a position where the grasp was comfortable, with the wrist maintaining a neutral position. the range of motion for shoulder rotation was set identically for everyone unless any discomfort was experienced. the test velocities were set at 90°.s-1 and 180°.s-1. both concentric and eccentric muscle actions were tested and gravity corrected. the order of testing proceeded from the slow speed to the fast speed and was standardised for all subjects. each subject was given the opportunity to familiarise himself with the dynamometer prior to the testing. a 1-minute rest period was observed between trials and test repetitions. cybex norm soft motion stops were placed at a range of movement (rom) 150° apart. the test protocol was standardised for all subjects. after a sufficient rest period following the cybex testing, flexibility was tested using a leighton flexometer.15 internal rotation was assessed passively in a supine position with the elbow flexed at 90° and the arm abducted at 90°. rotation was measured up to a point where the athlete started to complain of pain or the humeral head began to protrude anteriorly, or no further rom could be acquired.11 external rotation was also assessed passively in the same position. the same criteria were used for endpoints; however, extension of the thoracic spine was used as an endpoint and not humeral head protrusion. in order to determine the classification of the bowling action each bowler was videotaped from the front, side and back. an expert coach was asked to classify each fast bowler's action into one of 3 actions.9 the side-on action requires a relatively slow run-up with the shoulders and hips pointing down the pitch to the wickets at the batsman's end at the time of back-foot placement in the delivery stride. the front-on action requires a faster run-up with a more openchest position at back-foot placement, with the shoulders and hips pointing towards third slip. the semi-front-on technique is based on the same principles as the above, with the alignment of the hips and shoulders pointing between the wickets at the batsman's end and third slip. the statistical service (rau) statcon was used to compute single variable statistics, including means, standard deviations, minimums, maximums and level of significance. the 0.01% level of significance was used for all tests. results the bowlers were classified as front-on (n = 7), side-on (n = 7) and semi-front-on (n = 7). of these, 12 had not sustained a shoulder injury to their bowling arm, while the other 9 had sustained a chronic shoulder injury to their bowling arm. the results revealed that 5 of the 7 bowlers with a front-on technique had chronic shoulder injuries. bowlers with the sideon and semi front-on bowling techniques reported 2 injuries each, with 1 of these injuries being a chronic shoulder injury. the absolute concentric and eccentric torque measured at 90°.s-1 and 180°.s-1 for internal shoulder rotation was not different between the injured and uninjured groups. however, when the concentric internal rotation was weight-normalised, the injured subjects had a higher torque at 180°.s-1 (65.20 ± 10.30 versus 45.91 ± 10.26; injured versus uninjured; p = 0.009) (table i). the peak torque values of shoulder external rotation showed no significant difference between the injured and uninjured groups and within groups between the velocities (table ii). the absolute torque ratios between the injured 26 sports medicine vol 16 no.1 2004 table i. torque values for internal shoulder rotation at angular velocities of 90° and 180° injured (n = 9) uninjured (n = 12) mean sd mean sd p-value absolute concentric (nm) 90° 44.50 11.05 40.67 10.64 0.464 180° 37.88 11.42 36.82 9.65 0.827 absolute eccentric (nm) 90° -52.50 13.64 -45.08 11.35 0.225 180° -46.50 7.75 -44.55 8.91 0.617 normalised concentric (nm/kg) 90° 51.94 11.39 51.83 11.97 0.984 180° 65.20* 10.03 45.91 10.26 0.009 normalised eccentric (nm/kg) 90° 44.11 10.91 54.67 13.31 0.069 180° 57.69 9.67 53.55 8.24 0.344 *p = 0.009 injured versus uninjured. and uninjured subjects for external and internal shoulder rotation showed no significant differences (table iii). however, the results for some subjects showed a muscle imbalance at both speeds, possibly predisposing them to injuries. all of the subjects except 5 had very low ratios. due to eccentric values increasing with velocity, the ratio value should also increase. however, only a minor increase was shown in the results. the results for the internal and external shoulder rotation flexibility of the injured and uninjured fast bowlers showed no significant difference between the groups (table iv). there was an increase in the external rotation ranges of movement for both groups, indicating a degree of hypermobility in both groups.14 discussion the isokinetic strength characteristics of the internal/external rotator shoulder muscles, shoulder flexibility and bowling action of provincial fast bowlers are presented, with the principal finding indicating the relationship between these variables and the incidence of chronic shoulder injury in the bowling arm. although the sample size is very small, the results support previous research that shoulder injuries are more common in fast bowlers with a front-on action than bowlers with a side-on or semi front-on action.10 in the side-on action the ball velocity is generated by contributions from the run-up (20 %), leg action and hip rotation (24%), trunk and shoulder rotation (11%), arm (41%) and hand and wrist (5%).6 although no research data are available on the contribution of various body segments to the ball velocity for the front-on action, the front-on bowling action requires a faster run-up (4.5 m.s-1) than the side-on (3.9 m.s-1), as well as a faster arm action.9 this faster arm action places more stress on the shoulder joint, predisposing these bowlers to shoulder injuries. during the bowling action's acceleration phase, the external rotators are contracted eccentrically in order to decelerate and control the arm and any external shoulder rotation weakness could contribute to impingement syndrome.17 at 180°.s-1 the uninjured group showed greater concentric and eccentric weight-normalised peak torque values for internal rotation than external rotation. the greater relative strength of the internal rotators compared with the external rotators, would indicate a decreased deceleration of internal rotation resulting in migration of the humeral head and thus a decrease in the subacromial space causing impingement of the rotator cuff tendon. thus fast bowlers should be advised to strengthen their external rotators to about 66% and 100% of the internal rotator concentric and eccentric strength, respectively.3 the fast bowler needs to decelerate the arm effectively from 6000°.s-1, resulting in an increase in the peak torque forces.2,4 eccentric external rotation showed a decrease in peak torque as the velocity increased. this is not congruent with the velocity-curve graph and could predispose the players to injury as this may cause the prime movers (anterior deltoid and pectoralis major) to superiorly translate the humeral head into the subacromial space, resulting in rotator cuff impingement.3 the eccentric external/concentric internal rotation ratio is a functional ratio. when a bowler delivers the ball, the internal rotators are concentrically contracted in order to accelerate the arm. in order to decelerate the arm after ball release the external rotators are contracted eccentrically. to achieve high ball delivery speeds the external eccentric forces must be great enough to balance these concentric and eccentric contractions, with a relationship between dysfunction and injury.2,7,8,18 sixteen of the 21 fast bowlers showed low stability ratios (table iii), compared with gravity corrected functional ratios of between 117 nm and 160 nm,12 indicating an imbalance and the presence of possible dysfunction. further, the concentric external-internal rotation also indisports medicine vol 16 no.1 2004 27 table ii. torque values for external shoulder rotation at angular velocities of 90° and 180° injured (n = 9) uninjured (n = 12) mean sd mean sd p-value absolute concentric (nm) 90° 34.25 11.26 31.33 7.84 0.537 180° 29.50 9.49 27.91 6.61 0.691 absolute eccentric (nm) 90° -44.63 11.02 -40.24 7.37 0.363 180° -42.38 10.81 -38.00 5.93 0.324 normalised concentric (nm/kg) 90° 36.59 6.90 39.58 6.95 0.359 180° 30.81 4.77 35.00 6.72 0.131 normalised eccentric (nm/kg) 90° 52.23 11.33 51.83 7.91 0.933 180° 49.32 10.53 47.82 5.96 0.723 table iii. torque ratios for external and internal shoulder rotation at angular velocities of 90° and 180° uninjured injured (n = 9) (n = 12) mean sd mean sd p-value absolute concentric ratio 90° 72.13 15.92 78.58 12.83 0.356 180° 73.88 17.68 78.18 13.17 0.571 absolute eccentric ratio 90° 103.63 28.11 104.17 23.74 0.965 180° 117.38 36.74 107.64 23.38 0.523 table iv. internal and external shoulder rotation flexibility (°) injured (n = 9) uninjured (n = 12) mean sd mean sd p-value internal rotation 84.00 10.77 89.75 17.26 0.361 external rotation 116.22 10.26 116.83 7.91 0.884 28 sports medicine vol 16 no.1 2004 cates a muscle imbalance at both speeds possibly predisposing these players to injury or re-injury due to previous chronic shoulder injuries that may not have been fully rehabilitated. athletes with impingement syndrome show a high degree of hypermobility in the anterior capsule of the shoulder, with excessive external rotation rom and general ligament laxity of the glenohumeral joint. these are contributory factors to developing impingement.20 the shoulder hypermobility of these groups of fast bowlers, as indicated by an increase in external rotation of the shoulder, may be a risk factor in the development of an impingement injury. the demands placed on the shoulder of a fast bowler are great and any muscle imbalances in the shoulder region could result in injury or reinjury. the difference between the uninjured and injured groups in the concentric internal rotation peak torque/body weight at 180°.s-1 indicates muscle imbalance in the rotator cuff muscles, which combined with a fast delivery speed with a front-on bowling action, may be a predisposing factor for shoulder injuries in cricket fast bowlers. although no significant differences were found between the injured and uninjured subjects, the results indicate that imbalance in the rotator cuff muscles, combined with a front-on bowling action, may be a predisposing factor for impingement syndrome in cricket fast bowlers. thus, bowler, coaches and fitness trainers need to ensure that fast bowlers follow a specific shoulder strengthening and flexibility programme to reduce the risk of injury. further, the personnel involved with the rehabilitation of the player after a shoulder injury need to continually assess the strength and flexibility of the shoulder and the ratios between the strength of agonist and antagonist muscle groups. only when fully recovered should a player be allowed to return to match play otherwise the player runs the risk of re-injury and a shortened career with further shoulder problems. references 1. anderson mk, hall sj, martin m. sports injury management. 2nd ed. philadelphia: lippincott williams & wilkins, 2000. 2. brown l. isokinetics in human performance. champaign, il: human kinetics, 2000. 3. brukner p, khan k. clinical sports medicine. sydney: mcgraw-hill, 1993. 4. codine p, bernard pl, pocholle m, benaim c, brun v. influence of sports discipline on shoulder rotator cuff balance. med sci sports exerc 1997; 29:1400-5. 5. crisp ta. cricket injuries. sports therapy 1990; 1(1):22-3. 6. davis k, blanksby b. the segmental components of fast bowling in cricket. australian journal for health, physical educationand recreation 1976; 71: suppl, 6 8. 7. donatelli ra, ellenbecker t, ekedahl s, wilkes js, kocher pt, adam j. assessment of shoulder strength in professional baseball pithcers, j orthop sports phys ther 2000; 30: 544-51. 8. dvir z. isokinetics: muscle testing, interpretation and clinical applications. edinburgh: churchill-livingstone, 2000. 9. elliott bc, foster dh. a biomechanical analysis of the front-on and sideon bowling techniques. journal of human movement studies 1984; 10: 83 94. 10. foster d. injury and prevention in fast bowling. proceedings of the australian sports medicine federation annual scientific conference, perth, australia, 1984. 11. gore cj. physical tests for elite athletes. australian sports commission. champaign, il: human kinetics, 2000. 12. guillermo j. isokinetic eccentric-to-concentric strength ratios of the shoulder rotator muscles in throwers and nonthrowers. am j sports med 2003; 10: 537 41. 13. hall sj. basic biomechanics. 3rd ed. boston: mcgraw-hill, 1999. 14. heyward vh. advanced fitness assessment and exercise prescription. 3rd ed. champaign, il: human kinetics, 1997. 15. king ga. internal and external shoulder rotator strength of cricketers vs. non-cricketers: an isokinetic comparison. masters thesis, rhodes university, grahamstown, south africa, 1997. 16. luttgens k, deutsch h, hamilton n. kinesiology: scientific basis of human motion. 8th ed. madison, wisconsin: brown and benchmark, 1992. 17. newsham kr, keith cs, saunders je, gaffinett as. isokinetic profile of baseball pitchers' internal and external rotation 180, 300, 450°.s-1, med sci sports exerc 1998; 30: 1489-95. 18. perrin dh. isokinetic exercise and assessment. champaign, il: human kinetics, 1993. 19. stretch ra. the incidence and nature of injuries in schoolboy cricketers. s afr med j, 1995; 85: 1182-4. 20. wilk ke, arrigo c. current concepts in the rehabilitation of the athletic shoulder. j orthop sports phys ther 1993; 18: 365. 1 s af. j sports med vol. 28 no.2 supplement 2016 2 s af. j sports med vol. 28 no.2 supplement 2016 hosted by sponsors http://utcimaging.com/ http://www.inqababiotec.co.za/ http://www.grootconstantia.co.za/ http://www.sasma.org.za/ 3 s af. j sports med vol. 28 no.2 supplement 2016 contents o1: persistence of tendon inflammation: a leading role for the stroma? ........................................... 5 o2: role of immune cells on tendon disease: insights from an in vitro model ................................... 6 o3: altered structure integrity is associated with pain and dysfunction in volleyball players with patellar tendinopathy .......................................................................................................................... 6 o4: altered structure integrity is associated with pain and dysfunction in junior elite athletes with patellar tendinopathy .......................................................................................................................... 7 o5: mechanical properties of the plantaris and achilles tendons: a contributing factor to noninsertional achilles tendinopathy? ..................................................................................................... 8 o6: can imaging diagnose and predict the morbidity of achilles and patellar tendinopathy in elite australian football players? ................................................................................................................. 8 o7: quantifying tendon stiffness in achilles and patellar tendinopathy and healthy controls using shear wave elastography: a blinded, cross-sectional investigation. .................................................. 9 o8: evaluation of intratendinous displacement and strain in the achilles tendon using quantitative high-frequency ultrasound imaging and an interactive clinician-friendly application. ....................... 10 o9: the epidemiology of achilles tendinopathy in uk runners ........................................................ 11 o10: patellar tendon structure responds to load over a 7-week preseason in elite volleyball players. .......................................................................................................................................................... 11 o11: immediate effects of altering sagittal plane trunk position during jump-landings in athletes with and without patellar tendinopathy ..................................................................................................... 12 o12: comparison of the mechanical properties between healthy tendon and tendon pathology using ultrasound elastography: a systematic review. ....................................................................... 13 o13: do symptomatic achilles tendons contain sufficient aligned fibrillar structure? ...................... 14 o14: statin treatment is associated with trigger finger ..................................................................... 15 o15: development and validation of the visa-a(sedentary) questionnaire: a modified version of the visa-a for nonathletic patients with achilles tendinopathy. ....................................................... 15 o16: increased upper trapezius muscle stiffness is associated with less reduction of the subacromial space in athletes with rotator cuff tendinopathy ........................................................... 16 o17: no effect of cox-2 inhibition on the composition of inflammatory cell populations during early and mid-time tendon healing ............................................................................................................ 17 o18: what does normal tendon structure look like? new insights into tissue characterisation in the achilles tendon.................................................................................................................................. 17 o19: the sympathetic nervous system is a factor in chronic achilles tendinopathy: an in vivo study ................................................................................................................................................. 18 o20: decrease in tendon strain is associated with intensity of pain in jumping athletes with patellar tendinopathy ..................................................................................................................................... 19 o21: evaluating somatosensory and psychological profiles of participants with patellar and achilles tendinopathy: a single-blind case-control study design .................................................................... 20 o22: immediate effects of one session of extracorporeal shock wave therapy on the elasticity of tendon in athletes with patellar tendinopathy ................................................................................... 21 o23: pressure pain thresholds? don’t do what we did! ................................................................... 21 o24: interrogating the role of angiogenesis genes on musculoskeletal soft tissue injury risk ......... 22 o25: microvascular volume in symptomatic achilles tendons is associated with visa-a score, but does not predict esw-induced intrinsic tendon tenderness ............................................................. 23 o26: plantaris excision and achilles tendon scraping is associated with reduction in pain and improvement in tendon structure in patients with mid-portion achilles tendinopathy ....................... 24 o27: fat pad adjacent to tendinopathy: coincidental or causal? ...................................................... 25 4 s af. j sports med vol. 28 no.2 supplement 2016 o28: botulinum toxin a blocks the release of acetylcholine from tendon cells – a novel role for botox in treating tendinopathy? ......................................................................................................... 25 o29: collagen genes and risk of carpal tunnel syndrome ........................................................... 26 o30: disruption of tgfβ signaling in the scleraxis cell lineage – a genetic model of tendon degeneration .................................................................................................................................... 27 o31: a cross sectional study correlating ultrasound tissue characterisaton and shear wave elastography in normal and tendinopathic achilles tendons ............................................................ 27 5 s af. j sports med vol. 28 no.2 supplement 2016 o1: persistence of tendon inflammation: a leading role for the stroma? sg dakin 1 , fo martinez 1 , mh al-mossawi 1 , r hedley 1 , k wheway 1 , b watkins 1 , cd buckley 2 , aj carr 1 1 botnar research centre, nuffield department of orthopaedics, rheumatology and musculoskeletal sciences, university of oxford, united kingdom; 2 institute of inflammation and ageing, university of birmingham, united kingdom. presenting author e-mail address: stephanie.dakin@ndorms.ox.ac.uk introduction: the mechanisms underpinning the development of chronic inflammation in tendinopathy are poorly understood. recent work has highlighted the plasticity of macrophage activation signatures in human supraspinatus tendinopathy (1), however the contribution of resident stromal cells to the inflammatory response has not been investigated. stromal activation is reported in rheumatoid arthritis in which resident stromal cells fail to switch off their inflammatory programme (2). in this study, we investigate the potential role of tendon stromal cells as an important population implicated in the development of chronic inflammation. methods: we studied stromal activation signatures in tendons obtained from patients before and after sub-acromial decompression treatment. some patients became pain-free after treatment and in some pain persisted. tendons were classified as early, intermediate or advanced stage disease. healthy tendons were collected from patients undergoing shoulder stabilisation surgery or acl repair. markers of stromal activation (gp38/podoplanin, cd248 and vcam) were investigated by flow cytometry and immunostaining of tendon tissues. gene array, qpcr and flow cytometry were used to investigate stromal activation in vitro. results: diseased tendon tissues showed increased gp38, cd248 and vcam mrna compared to healthy supraspinatus tendons (p=0.01). this stromal activation signature persisted in painful and pain-free patients 2-4 years after treatment. diseased cells showed increased basal gp38, cd248 and vcam mrna compared to healthy cells (p<0.05). treatment of healthy and diseased cells with il-1 or tnf increased gp38 and vcam mrna and protein. il-1 treated diseased cells showed increased gp38 mrna compared to il-1 treated healthy cells (p=0.03). cytokine treatment did not induce expression of cd248. treatment of diseased cells with lps increased expression of nfb and interferon inducible target genes compared to lps treated healthy cells. discussion: we demonstrate inflamed tendon tissues show increased expression of stromal fibroblast activation markers compared to healthy tendon tissues and cells. cytokine stimulation induced markers of activation including gp38 and vcam but not cd248, suggesting distinct stromal responses in diseased tendons. persistence of the stromal activation signature after treatment suggests tendon stromal cells may be continuously primed for inflammation. stromal activation and memory may be an important mechanism for the development of chronic inflammation and recurrent tendon disease. references: 1. s. g. dakin, f. o. martinez, c. yapp, g. wells, u. oppermann, b. j. dean, r. d. smith, k. wheway, b. watkins, l. roche, a. j. carr, inflammation activation and resolution in human tendon disease. science translational medicine 7, 311ra173 (2015). 2. r. patel, a. filer, f. barone, c. d. buckley, stroma: fertile soil for inflammation. best pract res clin rheumatol 28, 565-576 (2014). acknowledgements: this work was funded by arthritis research uk grant 20506 and the nihr oxford musculoskeletal biomedical research unit. 6 s af. j sports med vol. 28 no.2 supplement 2016 o2: role of immune cells on tendon disease: insights from an in vitro model ad schoenenberger 1,2 , j foolen 1,2 , u silvan 1,2 and jg snedeker 1,2 1 department of orthopaedics, balgrist hospital, university of zurich, zurich, switzerland; 2 institute for biomechanics, eth, zurich, switzerland. presenting author e-mail address: angelina.schoenenberger@hest.ethz.ch introduction: the cellular mechanisms of tendinopathy remain unclear particularly with respect to the importance of inflammation in both the pathogenesis of tendinopathy and the healing process. recent immuno-histochemical studies have revealed the presence of immune-competent cells in both early and chronic human tendinopathy. the evidence that inflammation coexists with degenerative changes in tendon opens questions regarding potential crosstalk between immune-cells and tendon fibroblasts (tfs). to shed light on this process we investigated the effects of polarized macrophage interaction with tendon cell behavior in a novel in vitro model of tendinopathy. methods: primary human tfs were seeded on nanofiber polymer mats that were structured to mimic the characteristic matrix of healthy vs diseased tendon. a tf/macrophage transwell system was used, allowing exchange of soluble factors without direct cell-cell contact. briefly, thp-1 monocytes, differentiated to macrophages (m0), were chemically polarized to the pro-inflammatory m1-like phenotype or the anti-inflammatory m2-like phenotype validated using surface markers cd197 (m1) and cd206 (m2). tf response was assessed using lineage-specific markers tenomodulin, scleraxis and mohawk, collagen i/iii and matrix remodelling capacity as indicated by matrix metalloproteinases (mmp). results: the extracellular matrix structure highly affected tf morphology, with models of healthy matrix yielding highly elongated cells and model tendinopathic matrices yielding more polygonal cells spread over multiple fibers. no notable changes in tendon marker expression were detected between substrate types. on the tendinopathic substrate models, tf stimulation by pro-inflammatory cytokines increased mmp 1, 3, and 13 expressions, compared to those on healthy matrix models. discussion: we established a combined in vitro system to study the effect of different factors on tendon cells displaying normal and pathological matrix phenotype. using this approach, we explored the effect of immune cells and factors secreted by immune cells on human primary tfs and observed increased expression of genes related with ecm turnover in ‘pathological’ tfs exposed to proinflammatory cytokines. these results are consistent with previously published reports of ‘molecular inflammation’. our minimal tendinopathy model driven by tendinopathic matrix structure indicates existence of crosstalk between immune cells and tfs that are relevant to understanding of tendon disease. o3: altered structure integrity is associated with pain and dysfunction in volleyball players with patellar tendinopathy z cai 1 , j li 2 , p luo 3 , p malliaras 4 , l masci 5 , w zhang 6 , j fang 6 , sn fu 1 1 department of rehabilitation sciences, the hong kong polytechnic university, hong kong (sar), 2 china sports bureau of guangdong province, china, 3 guangdong vocational institute of sports, china, 4 complete sports care, australia, 5 pure sports medicine, london, united kingdom, 6 guangdong sports hospital, china, presenting author e-mail address: zoe.cc.cai@polyu.edu.hk introduction: altered tendon integrity has been reported in athletes with achilles tendinopathy. the present project aimed to compare tendon integrity between healthy and volleyball athletes with patellar tendinopathy; as well as to explore possible relationship between abnormal tendon integrity, pain and dysfunctions in those with patellar tendinopathy. methods: twenty-two elite volleyball players (mean age =20.7 ±1.; bmi=32.0 ± 6.2; 8 male; mean training hour per week = 30) were recruited. fourteen had patellar tendinopathy (5 had unilateral patellar tendinopathy and 9 had bilateral tendinopathy) determined by clinical assessments. both 7 s af. j sports med vol. 28 no.2 supplement 2016 knees were scanned using the ultrasound tissue characterization system. four echo types were discriminated and expressed as a percentage. visual analogue scale (vas) was used in quantifying the intensity of pain on palpation and during single-legged declinedsquat test. the victorian institute of sports assessment scale (visa-p) was used in measurement dysfunctions. results: significant increase in the proportion of echo type iii+ vi was observed in athletes with patellar tendinopathy than control (p <0.05). the proportion of iii+iv was increased from 12.1% to 28.1%; and from 12.9% to 26.3% in the right and left knees, respectively. correlations were found between the proportion of echo iii+iv and the visa-p scale. specifically, a trend of negative correlation was detected between the proportion of echo iii+iv and scores of question 4 of the visa-p scale (pain when doing a full weight-bearing lunge) (rho = -0.51, p=0.078) in 13 subjects with right patellar tendinopathy and the visa-p scores (rho= 0.61, p=0.059) in 10 subjects with left tendinopathy. discussion: increase in abnormal tendon structure was observed in elite volleyball players with patellar tendinopathy. these athletes lived in a training institute and trained 5 days a week and 6 hours a day. most of the players with tendinopathic tendon still practiced with pain; and were able to squat fully without pain. during full-weight forward lunge, the activity-induced patellar pain had a trend of relationship with the abnormal tendon structure in subjects with right patellar tendinopathy. these findings suggest that more severe structural tendon changes show a trend towards a relationship with pain during tendon loading. o4: altered structure integrity is associated with pain and dysfunction in junior elite athletes with patellar tendinopathy sn fu 1 , j li 2 ,l mascil 3 , w zhang 4 , j fang 4 , p luo 5 , p malliaras 6 , z cai 1 1 department of rehabilitation sciences, the hong kong polytechnic university, hong kong (sar), 2 china sports bureau of guangdong province, china, 3 pure sports medicine 116 cromwell rd london, united kingdom, 4 guangdong sports hospital, china, 5 guangdong vocational institute of sports, 6 complete sports care, australia, presenting author e-mail address: amy.fu@polyu.edu.hk introduction: altered tendon integrity has been reported in adult athletes. whether similar phenomenon happens in junior elite athletes is unknown. although an increase in abnormal tendon structure has been observed in subjects with tendinopathy, the relationship between tendon structure, pain and dysfunction is unclear. the present project aimed to compare tendon integrity between junior healthy and athletes with patellar tendinopathy and to explore possible relationships between abnormal tendon integrity, pain and dysfunctions in junior elite athletes with patellar tendinopathy. methods: thirty-seven junior elite athletes (age ranged from 14-18 years; 26 male; mean training hour per week = 30; 19 volleyball players and 18 weight lifting athletes) were recruited. fourteen of them had patellar tendinopathy (5 had unilateral right patellar tendinopathy and 9 had bilateral tendinopathy) determined by clinical assessments. the right knee was scanned using the ultrasound tissue characterization system. four echo types were discriminated and expressed as a percentage. visual analogue scale (vas) was used in quantifying the intensity of pain on palpation and during single-legged declined-squat test. the victorian institute of sports assessment scale (visa-p) was used in measurement dysfunctions. results: significant increase in the proportion of echo type iii+ vi was observed in athletes with patellar tendinopathy than the control (p <0.05). echo iii+iv was increased from 11% in the healthy to 24% in the tendinopathic tendons. positive correlations were found between echo iii+iv and intensity of pressure pain (rho=0.81, p=0.000) and intensity of single-legged decline-squat test pain (rho= 0.83, p=0.000); as well as negatively correlated with visa-p score (rho =-0.55, p= 0.053). discussion: altered tendon structure was observed in junior elite athletes with patellar tendinopathy. the athletes lived in a training institute and trained 5 days a week with same training intensity. those with patellar tendinopathy had not modified their training schedule. however, abnormal tendon structure was associated with pain and dysfunctions in these athletes. our findings suggest more severe changes in structure are related to pain and dysfunction in the junior elite athletes. 8 s af. j sports med vol. 28 no.2 supplement 2016 o5: mechanical properties of the plantaris and achilles tendons: a contributing factor to non-insertional achilles tendinopathy? joanna stephen 1,2 , breck lord 2 , lorenzo masci 3 , james calder 1,4 , andrew amis 2,4 an investigation performed at imperial college london 1 fortius clinic, 17 fitzhardinge st, london w1h 6eq; 2 biomechanics group, department of mechanical engineering, imperial college london, uk 3 st georges hospital, london, uk; 3 pure sports medicine, 116 cromwell rd, london sw7 4xr; 4 musculoskeletal surgery group, department of surgery and cancer, imperial college london school of medicine, charing cross hospital, london, uk presenting author e-mail address: lorenzo@sportsdoctorlondon.com introduction: the plantaris tendon (pt) has been implicated in non-insertional achilles tendinopathy (niat), but its precise role is not clearly understood. it is hypothesised to friction against the medial achilles, potentially causing a neuro-inflammatory response. different mechanical properties of the tendons could be a causative factor, resulting in elongation differences between the two tendons in response to loading. a prior study found pt is stiffer than achilles tendon(at) however young’s modulus was not reported, since testing equipment limited loading to 200n. thus pt was only compared to sectioned parts of the at, likely affecting its behaviour given its twisted structure. the purpose of this work was to define the mechanical properties of whole at and pt taken from young specimens, with normal tendon morphology. methods: an ultrasound tissue characterisation scan (utc) was performed on ten fresh frozen cadaveric ankles(mean age=32±7(m±sd) range:22-39; female=6). pt and at were dissected out and cross-sectional area recorded using a validated alginate mould and digital photography method. tendons were individually tensile tested to failure at 1,000 mm/min, by gripping ends in freezing clamps, using an instron machine(instron limited, uk). sutures were positioned 50mm apart on the tendons, 10mm proximal and distal to the freezing clamp edge and tracked using a high speed video camera synchronised with the load values. results: cross sectional area (csa) of at(68±14mm 2 (mean±sd)) was significantly greater than pt (3±1mm 2 )(p<0.01). utc scans showed a mean 89% organised tendon in at 2-4cm from the calcaneal insertion. stress and strain curves were plotted and young’s modulus calculated. pt had a significantly higher modulus of elasticity (1.5gpa±0.3) than at (0.9gpa±0.4)(p<0.001). fracture forces for the at (3.6kn±0.5) were significantly higher than pt (0.3kn±0.1) due to csa differences (p<0.01). conclusion: accounting for csa, young healthy pt were significantly stiffer than at. this is the first time young’s modulus has been reported on same specimen, intact at and pt, using high frequency sampling (1000hz) and rapid tendon loading(1000 mm/min). findings explain why clinically the at may rupture and the pt remains intact, adding support to the premise of a friction phenomenon between at and pt in a sub-population of patients with niat. o6: can imaging diagnose and predict the morbidity of achilles and patellar tendinopathy in elite australian football players? si docking 1,2 , e rio 1,2 , j orchard 3 , l fortington 2 and j cook 1,2 1 la trobe sports and exercise medicine research centre, la trobe university, melbourne, australia, 2 australian centre for research into injury in sport and it’s prevention, federation university, ballarat, australia, 3 school of public health, university of sydney, sydney, australia presenting author e-mail address: s.docking@latrobe.edu.au introduction: the relevance of imaging in tendinopathy is widely debated due to the large proportion of asymptomatic pathology. furthermore, there is controversy regarding whether normalisation of tendon structure is required for clinical improvements in pain. this study aimed to investigate whether 9 s af. j sports med vol. 28 no.2 supplement 2016 the presence of pathology, amount of disorganisation, or changes in tendon structure over time predict the presence, or magnitude of symptoms, in achilles and patellar tendinopathy. methods: 474 elite male australian football players were recruited. all players completed the ostrc overuse questionnaire monthly during the preand competitive season to quantify the impact of achilles and/or patellar tendinopathy on participation and performance in training and games. a subset of 193 participants underwent ultrasound tissue characterisation (utc) scans of their achilles and patellar tendons at baseline, monthly intervals throughout the three month pre-season, and end of season. the presence of pathology on grey-scale ultrasound (hypoechoic area and/or tendon thickening) was assessed, as well as the percentage of disorganised structure (dis) quantified using utc. risk factor analysis was performed to identify any associations between the presence of pathology and symptoms. linear regression was performed to identify any potential relationship between the percentage of dis and ostrc score. results: 13.3% and 16.5% of participants reported some level of achilles or patellar tendon morbidity respectively. 66 players (40.5% of those scanned) exhibited a pathological patellar tendon on greyscale us, yet 26 of these players (39.4%) were asymptomatic. players with pathology on grey scale ultrasound at the start of the season were 7.3 (ci 3.6-14.7) times more likely to have symptoms. based on utc findings, participants with more than 5.8% of dis structure in the patellar tendon were 5.1 (ci 1.220.8) times more likely to have their participation and performance in training and games affected. no relationship was observed between percentage of dis structure and the ostrc overuse score (p=0.977, r=0.011). discussion: the presence of structural abnormalities was a risk factor for reduced participation and performance in training and games. in this population, imaging should not be used diagnostically due to the high proportion of asymptomatic tendon pathology and poor positive predictive value o7: quantifying tendon stiffness in achilles and patellar tendinopathy and healthy controls using shear wave elastography: a blinded, cross-sectional investigation. b coombes 1 , b vicenzino 2 , v vuvan 2 , r mellor 2 , l heales 3 , a nordez 4 , k tucker 1 , f hug 4 1 school of biomedical sciences, the university of queensland, brisbane australia; 2 school of health and rehabilitation sciences, the university of queensland, brisbane, australia; 3 school of human, health and social science, division of physiotherapy, central queensland university, rockhampton, australia; 4 laboratory for movement, interaction and performance, university of nantes, nantes, france presenting author e-mail address: b.coombes@uq.edu.au introduction: tendon injuries are characterized by changes in composition and structure, which may alter tendon mechanical properties. shear wave elastography is a relatively new ultrasound-based, non-invasive technique, which can be used to quantitatively assess the shear modulus or stiffness of tendon. to date, there is limited evidence from separate studies suggesting increased and decreased stiffness in patellar and achilles tendinopathy respectively. methods: a cross-sectional study was used to compare healthy individuals with those currently experiencing symptomatic (unilateral or bilateral) achilles tendinopathy (at) or patellar tendinopathy (pt). b-mode and elastography was performed using an aixplorer ultrasound scanner (supersonic imagine version 8.2). an examiner blinded to the presence (and region) of tendinopathy performed bilateral measures of patellar and achilles tendons, at both mid-tendon and insertional regions, in a randomised order. elastography images were processed offline using customised matlab scripts by a second researcher blinded to tendinopathy status. repeated measures ancova were used to examine the effect of condition (pt v c or at v c) and region (mid v insertional) on each measure. where significant interaction was found post-hoc testing was performed using generalised linear models. age, sex and bmi were included in all models. significance was set at 0.01. results: 67 participants (17 patellar tendinopathy, 22 achilles tendinopathy, 28 controls) were recruited. significant differences in age and bmi were found between groups, with at group being 10 s af. j sports med vol. 28 no.2 supplement 2016 older and more overweight. compared to controls, increased thickness (md 1.7mm, 95%ci 0.5 to 2.9, p=0.005) and increased stiffness (md 64.9kpa, 54.6 to 75.2, p<0.001) were found in the insertional (proximal) patellar tendon in patellar tendinopathy. compared to controls, decreased stiffness (md 27.2kpa, -43.1 to -11.3, p<0.001) was found at the achilles insertion in achilles tendinopathy, but not at the mid-tendon, where there was increased thickness (md 1.9mm, 0.5 to 3.3, p=0.01). achilles tendon stiffness was significantly negatively associated with age (b -0.5, 95% ci -0.9 to -0.1, p=0.007). conclusion: regional changes in tendon thickness and stiffness are evident in achilles and patellar tendinopathy. different mechanical demands and chronic tendon overload or underload may explain the increased stiffness in patellar and decreased stiffness in achilles tendinopathy respectively. o8: evaluation of intratendinous displacement and strain in the achilles tendon using quantitative high-frequency ultrasound imaging and an interactive clinician-friendly application. stijn bogaerts 1 , catarina carvalho 2 , koen peers 1 . 1 department of physical medicine & rehabilitation, university hospitals leuven, belgium; 2 medical imaging research centre, university of leuven, belgium presenting author e-mail address: stijn_bogaerts@hotmail.com or stijn.1.bogaerts@uzleuven.be introduction: knowledge on in vivo mechanical tendon behavior is scarce. previous research has provided insight in global as well as intratendinous tendon displacement, but information on in vivo intratendinous strain is absent. the objective of this study is to (a) investigate the reliability of a novel imaging technique using high-frequency ultrasound based speckle tracking, to establish a direct measure for local intratendinous displacement and strain. we hypothesize (b) non-uniform deformation with highest displacement in the deep layer, and highest strain in the superficial layer, when comparing superficial, middle and deep tendon layers. methods: a dynamic ultrasound of both achilles tendons of 10 asymptomatic subjects was taken during 2 repetitions of a passive elongation and an isometric contraction. after segmentation and post-processing of the images, the intratendinous deformation was estimated by means of speckle tracking. reliability of the method and non-uniform behavior (displacement and strain) between the three layers were evaluated. intraclass correlation coefficients between two repetitions were evaluated separately for each leg, activation method (passive, isometric), response variable (displacement, strain) and layer (deep, middle, superficial). results: icc’s were overall acceptable, ranging from 0,57 to 0,94 for displacement in the superficial layer for both legs and activation methods. there was a statistically significant (alpha-level 0,05) nonuniform displacement when comparing the superficial, middle and deep layers, for passive as well as isometric activation (p < 0,001). highest displacement was found in the deep layer. there was a statistically significant non-uniform strain, but only during passive activation, when comparing superficial, middle and deep layers (superficial versus middle: p = 0,03; superficial versus deep and middle versus deep: p < 0,001). highest strain was found in the superficial layer. discussion: we have proven adequate reliability of this new technique and have confirmed previously found (1,2) non-uniform tendon behavior with highest displacement in the deep layer. furthermore, we have shown a first insight in non-uniform strain behavior with highest strain in the superficial layer. this technique will improve the knowledge on etiology of tendinopathy, perhaps identify subjects at risk for developing pathology, and also provide options to optimize existing therapeutic loading programs. references: 1. arndt a, bengtsson a-s, peolsson m, thorstensson a, movin t. non-uniform displacement within the achilles tendon during passive ankle joint motion. knee surgery, sport traumatol arthrosc. 2012;20:1868–74. 2. slane lc, thelen dg. achilles tendon displacement patterns during passive stretch and eccentric loading are altered in middle-aged adults. med eng phys. 2015;37(7):712–6. 11 s af. j sports med vol. 28 no.2 supplement 2016 o9: the epidemiology of achilles tendinopathy in uk runners s o’neill, 1 , s barry 2 , p watson 3 1 department of medicine and biological sciences, university of leicester, united kingdom; 2 faculty of health and life sciences, coventry university, united kingdom; 3 department of health sciences, university of leicester, united kingdom presenting author e-mail address: so59@leicester.ac.uk introduction: achilles tendinopathy affects 2% of the general population and 52% of ex-elite middle/long distance runners. despite the high incidence levels reported in runners there have been few primary epidemiological studies and even fewer outside of elite sporting groups from various scandinavian countries. aims 1. determine the point and lifetime prevalence of achilles tendinopathy within uk runners 2. determine the associated factors for achilles tendinopathy within uk runners methods: a self-reported historical cohort study was completed using a survey. the survey was developed based on a delphi study of world tendon experts. the final survey was sent to 15,000 subscribers of a leading uk running magazine and was also run concurrently online. binary logistic regression analysis was used to determine important variables. results: 1800 subjects responded to the study with 1475 subjects completing all necessary components. lifetime prevalence of achilles tendinopathy was 57%, point prevalence was 44%. midportion tendinopathy was the most frequently reported (69%) with insertional (16%) and combined insertional and mid-portion (15%) accounting for the remaining %.the final logistic regression model comprised of statistically significant variables: number of years running, type of running, training surface, training terrain, weekly mileage, number of weekly runs, number of rest days, average running speed, age, ankle rom, calf stretching, previous calf pain, orthosis use, and lower limb strength training. this model had an accuracy of 65.1% with a sensitivity of 77.8% and a specificity of 47.7%. important extrinsic variables (odds ratios and 95%ci) were: running on grass (1.63,0.16–16.76), training on flat terrain (1.49,0.27–8.27), regularly calf stretching (1.78,1.32–2.35), wearing prescribed (1.94,1.30–2.89) or off-the-shelf orthosis (1.56,1.18–2.07), and regularly strength training (1.44,1.17– 1.77). important intrinsic variables were: restricted ankle rom (2.69,1.94-3.70) and regularly experiencing calf pain with running (1.80,1.43-2.25). discussion: achilles tendinopathy affects large numbers of endurance runners. extrinsic and intrinsic factors identified in this study should be used in further epidemiological studies, these variables may be important to consider in prevention studies. this study is the first to report previous calf pain, strength training and calf stretching as variables of interest in achilles tendinopathy. o10: patellar tendon structure responds to load over a 7-week preseason in elite volleyball players. lm rabello 1 , r ijtsma 2 , j zwerver 1 and ms brink 2 1 department of sports medicine, university of groningen, groningen, university medical center groningen, , the netherlands, 2 center of human movement science, university of groningen, groningen, the netherlands presenting author e-mail address: l.maciel.rabello@umcg.nl introduction: patellar tendinopathy is a common overuse injury in jumping sports, with higher incidence in volleyball players. different risk factors are associated with patellar tendon problems, including training load (frequency, volume and intensity). tendons show an adaptive or maladaptive response to load and the quality of its structure either improves or worsens. the aim of this study was 12 s af. j sports med vol. 28 no.2 supplement 2016 to investigate the relation between tendon load and the response of the patellar tendon structure of elite volleyball players. methods: seventeen elite male volleyball players participated in this study. volume (duration) and intensity (session rating of perceived exertion (rpe)) were recorded every training and match by each player. load was calculated by multiplying duration of the training and rpe. the cumulative load was defined by the sum of the weekly loads over 2 weeks before the utc scan. jump frequency was measured with accelerometers and with video notation analysis. to assess tendon structure changes, the ultrasound tissue characterization (utc) was used. the measures were assessed biweekly to quantify patellar tendon structure. generalized estimating equation (gee) models were used to test the relation between load parameters and echo pattern changes. results: on average, players spent 624 ± 215 minutes on training and matches per week with a rpe of 13.9 ± 2.1 indicating 'somewhat hard' intensity. jump frequency was 278 ± 122 per week. higher load parameters (volume, intensity and load) resulted all in a higher decrease of echo-type i (p<0.05). higher volume and load resulted in a higher decrease of echo-type ii (p<0.05). higher cumulative weekly volume and cumulative weekly loads between the first and the last utc were related to significant higher decreases in echo-type i (p<0.05), but not related for echo-type ii. no significant relations were found for jump frequency. none of the load parameters were related to echo-type iii and iv. discussion: the present study showed that load was related to changes in echo-types over a 7 week preseason in elite volleyball players. a higher amount of load was related to greater echo pattern changes. further research to the relation between load and echo pattern changes is needed. o11: immediate effects of altering sagittal plane trunk position during jumplandings in athletes with and without patellar tendinopathy r scattone silva 1 , c purdam 2 , a fearon 2,3 , w spratford 3,4 , c kenneally-dabrowski 4 , p preston 5 , fv serrão 1 , and je gaida 3 1 department of physiotherapy, federal university of são carlos, são carlos, brazil, 2 department of physical therapies, australian institute of sport, canberra, australia, 3 university of canberra research institute for sport & exercise (ucrise), canberra, australia, 4 movement science, australian institute of sport, canberra, australia, 5 canberra specialist ultrasound, canberra, australia. presenting author e-mail address: r.scattone@outlook.com introduction: pathomechanical models of tendinopathy emphasize overload as a key factor leading to the development of tendon pathology (1). therefore, it seems reasonable that interventions aimed at reducing tendon load during sports-related tasks may help in rehabilitation and prevention of tendinopathy. athletes with patellar tendon disorders use a stiffer landing pattern than asymptomatic controls (2). sagittal plane trunk position during jump-landings might influence patellar tendon forces and symptoms in athletes with patellar tendinopathy. this study examined the effect of altering trunk position during jump-landings on lower limb biomechanics, patellar tendon force and pain in athletes with and without patellar tendinopathy. methods: twenty-one elite and sub-elite male athletes were categorized into 3 groups, athletes with patellar tendinopathy (tg, n=7), asymptomatic athletes with patellar tendon abnormalities (ag, n=7) and asymptomatic athletes without tendon abnormalities (cg, n=7). motion-analysis and force plate data were collected during drop-jump landings with a self-selected (ss), flexed (flx) or extended trunk position (ext). the latter two conditions were randomized. sagittal plane peak kinematics, kinetics, patellar tendon force and pain during the landing tasks were calculated. results were analysed with a 2-way repeated measures anova. results: peak patellar tendon force, knee extensor moment and knee pain decreased in the flx landing compared to the ss landing, regardless of group. in addition, peak patellar tendon force, knee extensor moment and vertical ground reaction force were smaller in the flx landing compared to the mailto:r.scattone@outlook.com 13 s af. j sports med vol. 28 no.2 supplement 2016 ext landing. the tg had smaller peak ankle dorsiflexion than the cg during jump-landings, regardless of trunk position. discussion: landing with greater sagittal trunk flexion decreased patellar tendon force in elite jumping athletes. an immediate decrease in knee pain was also observed in symptomatic athletes with a more flexed trunk position during landing. increasing trunk flexion during landing might be an important strategy to reduce tendon overload in jumping athletes. increasing ankle dorsiflexion during landing might also be important in athletes with patellar tendinopathy. references: 1. cook & purdam. br j sports med, 43:409-16, 2009. 2. van der worp et al. int j sports med, 35:714-22, 2014. o12: comparison of the mechanical properties between healthy tendon and tendon pathology using ultrasound elastography: a systematic review. b coombes 1 , i willis 1 , a nordez 2 , f hug 2 , k tucker 1 1 school of biomedical sciences, the university of queensland, brisbane australia 2 laboratory for movement, interaction and performance, university of nantes, nantes, france presenting author e-mail address: b.coombes@uq.edu.au introduction: tendon injuries are characterized by substantial changes in composition and structure which lead to altered tendon mechanical properties. recent work suggests that direct or indirect estimation of tendon mechanical properties using ultrasound elastography may be useful in evaluation of tendon pathology, such as tendinopathy or tears. however large differences in technology, methodology and populations studied is evident between studies. a systematic review was performed to synthesise evidence and provide consensus regarding methodology, terminology and outcomes for future research. methods: five databases were searched using the terms elastography or sonoelastography and tendon (feb 2016). studies published in english using ultrasound elastography to compare mechanical properties of tendon between people with or without tendon pathology (tendinopathy or tear), or between affected and contralateral unaffected tendons were included. reviews, abstracts or case studies were excluded. two independent reviewers determined eligibility, assessed methodological quality and extracted data. results: abstracts and titles of 195 studies were identified for initial review. 16 studies (n=1010 individuals) met inclusion criteria, 13 of these provided comparison with a healthy control population. achilles tendon pathology was most commonly studied (7 studies, n=468), followed by lateral epicondylalgia (4 studies, n=198), rotator cuff (3 studies n=276) and patellar tendinopathy (2 studies, n=68). the majority of studies used compression or strain elastography (13 studies, n=822) where static compression imposed by the operator induces strain within the tissue. studies reported a qualitative grading of tendon softness/hardness or a relative strain ratio between the tendon and surrounding tissue. most studies concluded that tendinopathy was associated with tendon softening, although 1 study of achilles tendinopathy and 2 studies of post-surgical achilles repair described affected tendons as hard. only two studies used shear-wave elastography, where measurement of the speed of shear wave propogation through tendon enables quantitative estimation of tendon stiffness. these studies reported increased tendon stiffness for patellar tendinopathy while reduced stiffness for achilles tendinopathy or tear. conclusion: evidence suggests altered mechanical properties by tendinopathy may be detected using ultrasound elastography. this review provides recommendations to improve consensus regarding terminology and standardized application of qualitative and quantitative scoring methods. 14 s af. j sports med vol. 28 no.2 supplement 2016 o13: do symptomatic achilles tendons contain sufficient aligned fibrillar structure? s o’neill 1 , s docking 2 , s barry 3 1 department of medicine and biological sciences, university of leicester, uk; 2 college of science, health and engineering, la trobe university, australia; 3 faculty of health and life sciences, coventry university, uk presenting author e-mail address: so59@leicester.ac.uk introduction: ultrasound tissue characterisation (utc) provides a detailed quantification of the tendon matrix, recently pathological tendons were shown to have sufficient aligned fibrillar structure (afs) (1). however this study did not isolate symptomatic from the pathological tendons. it is possible that symptomatic tendons present a different pattern of structural integrity. aim to assess the aligned and disorganised fibrillar structure (dfs) of symptomatic achilles tendons compared to non-symptomatic tendons. methods: participants with and without achilles tendinopathy were recruited. 29 symptomatic tendons and 29 healthy tendons were included. using utc the area of greatest tendon echonicity was identified and most affected 10mm section contoured. contours were laid at 2mm intervals giving 50 contiguous transverse images which were automatically interpolated to form a tendon volume. analysis was completed using window size 9. the mean cross-sectional area (mcsa) of afs was quantified using utc algorithms. results: the mcsa of afs was 76.8 mm 2 (sd 28.5mm 2 ) in the symptomatic tendons and 69.7mm 2 (14.2mm 2) in the non-symptomatic tendons. the mcsa of the dfs was 40.9mm 2 (30.7mm 2 ) and 4.7mm 2 (2.4mm 2 ) respectively. mcsa of afs was not significantly different (p=0.237) between the groups. mcsa of dfs was significantly different between the groups (<p=0.001). a scatter plot of the mcsa of the symptomatic tendons plotted with the interquartile range (iqr) of the healthy tendons showed 21% (n=6) falling below the first quartile, 31% (n=9) falling within the middle two quarters and 48% (n=14) falling above the fourth quartile. discussion: our study demonstrates large changes in dfs in symptomatic tendons compared with non-symptomatic tendons. our study supports the previous findings of sufficient afs in the majority of subjects (79%) but highlights a subgroup (21% of symptomatic tendons) that appear to have insufficient afs. this is the first identification of this subgroup. the higher proportion with low afs in our study compared with previous work may be due to analysing a smaller section around the lesion rather than the whole tendon, also our study included symptomatic rather than pathological tendons. the group with low mcsa of afs may be at risk of tendon rupture, further work is needed to address these findings. references: 1. docking s and cook j (2015) pathological tendons maintain sufficient aligned fibrillar structure on ultrasound tissue characterization. scandinavian journal of medicine and science in sports, doi 10.11111/sms.12491 15 s af. j sports med vol. 28 no.2 supplement 2016 o14: statin treatment is associated with trigger finger p eliasson 1 , a-c lundin 1 , p aspenberg 1 , k michaëlsson 2 1 department of clinical and experimental medicine, faculty of health sciences, linkoping university, linköping, sweden, 2 section of orthopedics, department of surgical sciences, uppsala university, uppsala, sweden presenting author e-mail address: pernilla.eliasson@gmail.com introduction: statin medication is known to have relatively few side-effects, but recent research have suggested potential side effects on tendons, with tendinopathy or ruptures as the final consequence (1,2). but firm evidence for an association is lacking. the aim of the present study was to determine whether statin treatment is associated with a specific tendon disorder, trigger finger. methods: two population-based large swedish cohorts, the swedish mammography cohort (smc; n = 52 220 women) and the cohort of swedish men (cosm; n=40 713) were used for this study. a timedependent cox regression analysis was applied to determine the association between statin treatment and trigger finger. the multivariable analysis was adjusted for age, bmi, smoking, energy intake, corticosteroid use, quinolone use, diabetes mellitus and renal insufficiency. results: statin use was common both among women (37%) and men (44%). the most common statin used was simvastatin (67%) followed by atorvastatin (24%). women who had used statins had a higher incidence of trigger finger than those who had never used statins, with a crude hr of 1.44, and after multivariable-adjustment 1.21 (95% ci: 1.03-1.43). the risk among men was higher, hr 1.63 and after adjustment 1.42 (95% ci: 1.15-1.75). the risk seemed to be dose-independent. the highest risk was seen among users of rosuvastatin (hr among men 2.19, 95% ci: 1.33-3.62) and the lowest risk was associated with simvastatin (hr among men 1.33, 95% ci: 1.06-1.68). the increased risk was only seen with current use of statin (adjusted hr 1.5 among men, 95% ci: 1.21-1.85) but not among former users (adjusted hr 0.71, 95% ci: 0.38-1.31). discussion: statin use increases the risk of trigger finger, especially among men. the highest risk was associated with the use of rosuvastatin. the risk appears to be linked to current use of statins and disappears after the treatment has been stopped. references: 1. teichtahl aj et al. med j aust. 2016 feb 15;204(3):115-21. 2. marie i, et al. arthritis rheum. 2008 mar 15;59(3):367-72. o15: development and validation of the visa-a(sedentary) questionnaire: a modified version of the visa-a for nonathletic patients with achilles tendinopathy. j, raju 1 , r norris 2 , j gaida 3 , j cook 4 , s o’neill 5 1 department of physiotherapy, leicester royal infirmary, leicester, uk; 2 department of trauma and orthopaedics, aintree university hospital, liverpool, uk; 3 university of canberra research institute for sport and exercise (ucrise), australia; 4 la trobe sport and exercise medicine and science research centre, la trobe university, australia; 5 department of medicine and biological sciences, university of leicester, uk presenting author e-mail address: jaya-raju@hotmail.co.uk introduction: the visa-a is a condition-specific outcome measure for achilles tendinopathy. it was developed primarily for use in athletic individuals and may be less sensitive to clinical change in nonactive individuals with achilles tendinopathy. 16 s af. j sports med vol. 28 no.2 supplement 2016 aim to developed and validate a modified version of the visa-a suitable for non-athletic individuals. methods: limitations of visa-a were identified through participant focus groups, and consultation with tendinopathy clinicians. the preliminary version of visa-a(sedentary) ready for pilot testing was developed and refined until consensus was achieved among the authors. twenty-two non-athletic individuals with achilles tendinopathy, treated with routine care at the leicester royal infirmary, are included in this preliminary report. participants completed both the visa-a and visa-a(sedentary) at baseline, at day 3, and at discharge. at discharge participants completed the global rating of change scale (groc) to evaluate treatment success. results: reliability of visa-a(sedentary) was high (icc 0.992, n=22). at discharge, visa-a had improved by 7 points (95%ci 5.2 to 8.5, n=13) whilst the visa-a(sedentary) improved by 14 (95%ci = 9.8 to 19.0). visa-a(sedentary) correlated with groc (r=0.621, p=0.024) whereas visa-a did not (r=0.412, p=0.162). discussion: visa-a(sedentary) shows excellent test-retest reliability, and appears to be more sensitive to change in a non-athletic population. the correlation with patient perception of treatment success suggests that this tool is a valid method of measure pain and functional limitation in nonathletic individuals with achilles tendinopathy. o16: increased upper trapezius muscle stiffness is associated with less reduction of the subacromial space in athletes with rotator cuff tendinopathy ht leong 1 , f hug 2,3 , sn fu 1 1 department of rehabilitation sciences, the hong kong polytechnic university, hong kong (sar), china, 2 laboratory “movement, interactions, performance” (ea 4334), ufr staps, university of nantes, france, 3 nhmrc centre of clinical research excellence in spinal pain, injury and health, school of health and rehabilitation science, university of queensland, brisbane, australia presenting author e-mail address: annieleonght@gmail.com introduction: reduction of subacromial space (sas) during arm elevation may contribute to rotator cuff tendinopathy. excessive tension of the upper trapezius (ut) was suggested as either a compensatory strategy used to preserve the sas or aggravating factor to rotator cuff tendinopathy. this study aimed to determine whether the ut muscle stiffness is altered in athletes with rotator cuff tendinopathy compared to asymptomatic athletes and to investigate the relationship between the change in ut muscle stiffness and the sas during shoulder abduction in athletes with rotator cuff tendinopathy. methods: forty-three male volleyball players (17 asymptomatic and 26 with rotator cuff tendinopathy, mean age = 22.9±3.5 years) participated in the study. the sas was measured using b-mode ultrasound and ut shear modulus (used as an index of muscle stiffness) was quantified using supersonic shear imaging with arm positioned at 0°, 30° and 60° of shoulder abduction. 1 the percentage change in sas and ut shear modulus were calculated. results: athletes with rotator cuff tendinopathy exhibited a higher ut shear modulus than the asymptomatic athletes (all p<0.007). significant negative correlation was found between the change in ut shear modulus and sas during shoulder abduction from 0° to 60° in athletes with rotator cuff tendinopathy (r=-0.487, p=0.018). hence, stiffer ut was associated with less reduction of the sas during shoulder abduction from 0° to 60°. discussion: taking advantage of elastography to assess the ut muscle stiffness, the present study showed that athletes with rotator cuff tendinopathy exhibited higher ut shear modulus than the asymptomatic athletes. an increase in ut shear modulus was associated with less reduction of the sas during shoulder abduction in those with rotator cuff tendinopathy. our findings may suggest that an increase in ut muscle stiffness could be a compensatory strategy used by athletes with rotator cuff tendinopathy to preserve the sas and to reduce impingement during shoulder elevation. references: 17 s af. j sports med vol. 28 no.2 supplement 2016 1. leong ht, ng gyf, leung vyf, fu sn (2013) quantitative estimation of muscle shear elastic modulus of the upper trapezius with supersonic shear imaging during arm positioning. plos one 8(6): e67199. o17: no effect of cox-2 inhibition on the composition of inflammatory cell populations during early and mid-time tendon healing p blomgran 1 , r blomgran 2 , j ernerudh 3 , and p aspenberg 1 1 orthopaedics, 2 division of medical microbiology, 3 division of clinical immunology department of clinical and experimental medicine, linkoping university, sweden presenting author e-mail address: parmis.blomgran@gmail.com introduction: the regenerating tissue during early tendon healing is to a large part composed of leukocytes (cd45 + cells). in a rat achilles tendon model, the inflammation resolves between 5 and 10 days. in the same model, nsaids impair healing if given during the first 5 days, but after that it has a positive effect 1 . we therefore tested the hypothesis that an nsaid would exert its effects trough influencing the composition or size of the inflammatory cell population. methods: 24 rats underwent achilles tendon transection. rats were randomized to parecoxib treatment (6.4 mg/kg subcutaneously) or saline control. rats received injections day 0-2 and were euthanized day 3 or received daily injections day 6-9 and were euthanized day 10. the regenerating tissue was digested using collagenase prior to cell isolation. cells were then stained with antibodies (cd45, cd11b, cd68, ccr7, cd206, cd163, cd3, cd4, cd8a, cd25, foxp3) to characterize different sub-populations of macrophages and t cells. data was acquired using flow cytometry and two-way anova was used to test the hypothesis, using ccr7/cd206 ratio as dependent variable, and time and drug treatment as independent. results: there was a strong and significant effect of time on virtually all inflammatory cell subpopulations (cd45, cd11b, cd68, ccr7, cd163, cd206, cd3, cd4) (p < 0.001), but no significant effect of parecoxib at either time point. the ccr7/cd206 ratio was not affected by the drug treatment. the pattern of cell composition appeared quite similar between the parecoxib and control groups at each time point. discussion: nsaids strongly influence tendon healing 1 . our results suggest that this effect might not be mediated via changes in leukocyte composition, but possibly via changes in leukocyte behavior or via direct effects on mesenchymal-derived cells. an important effect of nsaids is to reduce levels of pge2, which is known to influence many mesenchyme-derived cell types through the ep2 receptor, thereby e.g. impairing fracture healing 2 . it seems that the term “non-inflammatory” covers only a small part of the effects of nsaids in tendon healing. references: 1. virchenko, o., skoglund, b. & aspenberg, p. parecoxib impairs early tendon repair but improves later remodeling. the american journal of sports medicine 32, 1743-1747 (2004). 2. li, m., thompson, d. d. & paralkar, v. m. prostaglandin e(2) receptors in bone formation. int orthop 31, 767-772, doi:10.1007/s00264-007-0406-x (2007). o18: what does normal tendon structure look like? new insights into tissue characterisation in the achilles tendon. e wezenbeek 1 , n mahieu 1 , tm willems 1,2 , d van tiggelen 1,3 , m de muynck 4 , d de clercq 5 , e witvrouw 1,6 1 department of rehabilitation sciences and physiotherapy, ghent university, ghent, belgium; 2 department of physical therapy and orthopedics, ghent university, ghent, belgium; 3 department of physical medicine & rehabilitation, military hospital of base queen astrid, belgian defence, brussels, belgium; 4 department of physical medicine and rehabilitation, ghent university hospital, mailto:parmis.blomgran@gmail.com 18 s af. j sports med vol. 28 no.2 supplement 2016 ghent, belgium; 5 department of movement and sport sciences, ghent university, ghent, belgium; 6 department of physiotherapy, aspetar, doha, qatar presenting author e-mail address: evi.wezenbeek@ugent.be introduction: recently ultrasound tissue characterisation (utc) was introduced as a reliable method for quantification of tendon structure. despite increasing publications on the use of utc, it is striking that there is a lack of normative data in active adolescents. therefore, the aim of this study was to provide normative values of the achilles tendon as quantified by utc. methods: seventy physiotherapy students (26 male and 44 female) with no history of achilles tendon injuries were recruited. the achilles tendons were scanned with utc to characterise tendon structure. results: this study demonstrated that achilles tendons of active, healthy adolescents contained 54.6% echo-type i, 42.8% echo-type ii, 2.2% echo-type iii, and 0.3% echo-type iv at midportion. the comparison between insertion and midportion of the tendon showed more echo-type ii at insertion (p<0.001). furthermore, female tendons contained significantly more echo-type ii, in both insertion and midportion compared to male tendons (p=0.004 and p=0.003, respectively). discussion: the results of this study, with respect to the mdc (minimum detectable change), highlight differences in the utc echopattern in the normal population (sex and regional location), which are important considerations for future studies. references: 1. counsel p, comin j, davenport m, connell d. pattern of fascicular involvement in midportion achilles tendinopathy at ultrasound. sports health 2015 september;7(5):424-8. 2. docking si, rosengarten sd, daffy j, cook j. structural integrity is decreased in both achilles tendons in people with unilateral achilles tendinopathy. j sci med sport 2014 july;18(4):383-7. 3. docking si, rosengarten sd, cook j. achilles tendon structure improves on utc imaging over a 5-month pre-season in elite australian football players. scand j med sci sports 2015 may 5. 4. lintz f, higgs a, millett m, barton t, raghuvanshi m, adams ma, winson ig. the role of plantaris longus in achilles tendinopathy: a biomechanical study. foot ankle surg 2010 december;17(4):2525. 5. magnusson sp, hansen m, langberg h, miller b, haraldsson b, westh ek, koskinen s, aagaard p, kjaer m. the adaptability of tendon to loading differs in men and women. int j exp pathol 2007 august;88(4):237-40. 6. rosengarten sd, cook jl, bryant al, cordy jt, daffy j, docking si. australian football players' achilles tendons respond to game loads within 2 days: an ultrasound tissue characterisation (utc) study. br j sports med 2015 february;49(3):183-7. 7. van schie ht, de vos rj, de js, bakker em, heijboer mp, verhaar ja, tol jl, weinans h. ultrasonographic tissue characterisation of human achilles tendons: quantification of tendon structure through a novel non-invasive approach. br j sports med 2010 december;44(16):1153-9. 8. van ark m, docking si, van da-s, i, rudavsky a, rio e, zwerver j, cook jl. does the adolescent patellar tendon respond to 5 days of cumulative load during a volleyball tournament? scand j med sci sports 2015 february 18. 9. waggett ad, ralphs jr, kwan ap, woodnutt d, benjamin m. characterization of collagens and proteoglycans at the insertion of the human achilles tendon. matrix biol 1998 march;16(8):457-70. o19: the sympathetic nervous system is a factor in chronic achilles tendinopathy: an in vivo study jl jewson 1 , ea lambert 2,3 , s docking 4,5 , m storr 4 , gw lambert 1,2 , je gaida 4,6,7 1 faculty of medicine, nursing and health sciences, monash university, melbourne, australia; 2 human neurotransmitters laboratory, baker idi, melbourne, australia; 3 department of physiology, monash university, melbourne, australia; 4 department of physiotherapy, monash university, melbourne, australia; 5 australian centre for research into injury in sport and its prevention, federation university, 19 s af. j sports med vol. 28 no.2 supplement 2016 ballarat, australia; 6 university of canberra research institute for sport and exercise (uc-rise), canberra, australia; 7 discipline of physiotherapy, university of canberra, canberra, australia presenting author e-mail address: jamie.gaida@canberra.edu.au introduction: tendinopathy is a common condition, which has been linked to surrogate measures of sympathetic nervous system (sns) activity and insulin resistance. this study aimed to compare in vivo measures of the sns and insulin resistance between individuals with and without achilles tendinopathy. methods: this case-control study compared achilles tendinopathy sufferers to healthy controls. sns activity was quantified using in vivo muscle sympathetic nerve activity (msna), which gave 4 measures of msna; burst frequency, burst incidence, units per minute and units per 100 heartbeats. insulin resistance was assessed via the matsuda index calculated from a modified oral glucose tolerance test. metabolic status was further documented with a fasting lipid panel. ultrasound tissue characterisation quantified tendon structure. results: resting msna did not differ between the 15 cases and 20 controls. tendon pain duration in tendinopathy patients was correlated with msna burst frequency (r 2 = 0.324, p = 0.027) and burst incidence (r 2 = 0.408, p = 0.010). after excluding an unexplained outlier, analysis by group revealed an association between reduced tendon structure and increased msna activity on all measures (r 2 = 0.144 – 0.170, p = 0.024 – 0.039). fasting glucose was slightly higher in cases than controls and weakly correlated with pain severity (r 2 = 0.140, p = 0.027), but no other metabolic measures were associated with tendon pain/structure. conclusion: this study suggests that increased sns activity is associated with tendon pain duration; building on previous data indicating the sns is involved in recalcitrant tendinopathy. metabolic parameters had little relationship with achilles tendinopathy in this metabolically homogenous sample. prospective studies are required to uncover the precise temporal relationship between sns activity, insulin resistance and tendon pain/structure. o20: decrease in tendon strain is associated with intensity of pain in jumping athletes with patellar tendinopathy wc lee 1 , zj zhang 2 , l masci 3 , gyf ng 1 , sn fu 1 1 department of rehabilitation sciences, the hong kong polytechnic university, hong kong (sar), china, 2 department of physical therapy, henan provincial orthopaedics hospital, henan, china, 3 pure sports medicine, london, united kingdom presenting author e-mail address: amy.fu@polyu.edu.hk introduction: changes in tendon mechanical properties is one of the proposed pathogenesis associated with tendinopathy. 1 the aim of this study was to explore the inter-relationships among tendon strain, intensity of self-perceived pain and activity-related pain in jumping athletes with patellar tendinopathy. methods: thirty-five male basketball, volleyball and handball players (mean age=22.4±4.0 years, 16 had unilateral symptoms) with patellar tendinopathy for more than 3 months (mean 31.9±25.4 months) participated in the study. tendon strain of the patellar tendon was examined by ultrasonography and dynamometry. the intensities of self-perceived pain (maximal pain on past 7 days and pain during single-legged declined-squat test) were enquired using visual analogue scale. results: partial correlation test was conducted with sports and side of affected knee as control variables. significant negative correlation between the patellar tendon strain and the maximal intensity of self-perceived pain (r=-0.49, p=0.005), and pain during single-legged declined-squat test (r=-0.36, p=0.045) were detected. body weight, age, nor duration of symptom was associated with the intensity of pain (all p>0.05). there is a trend of significant difference on tendon strain between subjects with unilateral and bilateral symptoms (9.0±3.7% & 11.6±4.1% respectively, p=0.058). 20 s af. j sports med vol. 28 no.2 supplement 2016 discussion: patellar tendon strain and intensity of pain are related. a higher tendon strain is associated with less intensity of self-perceived pain in jumping athletes with patellar tendinopathy. side of affected knee may affect the mechanical loading on the patellar tendon. our findings show that tendon mechanical property is associated with the intensity of tendon-related pain in athletes with patellar tendinopathy. references: 1. sconfienza lm, silvestri e, cimmino ma. sonoelastography in the evaluation of painful achilles tendon in amateur athletes. clinical and experimental rheumatology 2010;28(3):373-378. o21: evaluating somatosensory and psychological profiles of participants with patellar and achilles tendinopathy: a single-blind case-control study design ml plinsinga 1 , cp van wilgen 4,5,6 , ms brink 3 , v vuvan 1 , a stephenson 1 , lj heales 1 , r mellor 1 , bk coombes 2 , and b vicenzino 1 1 university of queensland, school of health and rehabilitation sciences: physiotherapy, university of queensland, st lucia, brisbane, 2 university of queensland, school of biomedical sciences, st lucia, brisbane, australia, 3 center for human movement sciences, university of groningen, university medical center groningen, groningen, the netherlands, 4 transcare transdisciplinary pain management center, groningen, the netherlands, 5 pain in motion research group, brussels, belgium, 6 department of physiotherapy and rehabilitation sciences, faculty of physical education and physiotherapy, vrije universiteit, brussel, brussels, belgium. presenting author e-mail address: m.plinsinga@uq.edu.au introduction: tendinopathy is characterized by pain and disability, which frequently persists. although persistent pain is frequently associated with sensitization within the central nervous system, there is a lack of evidence in lower limb tendinopathy. the aim was to evaluate somatosensory and psychological profiles of participants with patellar tendinopathy (pt) and achilles tendinopathy (at) compared to separate control groups. methods: we compared pt (mean age 29.5 years, n=19, 26% female) to healthy controls (26.7 years, n=15, 53% female), and at (45.7 years, n=30, 43% female) to healthy controls (41.0 years, n=11, 45% female). quantitative sensory testing (qst) consisting of 4 pain threshold tests and 3 sensory threshold tests were performed according to the german research network on neuropathic pain guidelines. 1 an assessor blinded to participants’ condition applied standardized qst to the infra patellar pole for pt, mid-achilles tendon for at and the lateral epicondyle (remote site) for both groups. participants completed the visa-p/visa-a, health-related quality of life, the hospital anxiety and depression scale, the active australia questionnaire and the mental toughness questionnaire. an ancova (mann whitney u test for ordinal data) was performed to compare groups, adjusting for sex, age and bmi. results: compared to controls, participants with pt displayed significantly lower pressure pain threshold over the affected patellar tendon (mean difference: -192.55 kpa; 95%ci -340.37, -44.72; p=0.012). no differences were found related to the remote site and for any other qst in pt and at. compared to controls, pt and at had significantly higher bmi (p=0.008, p=0.001 respectively) and lower quality of life (both p<0.001), while higher mental toughness scores were observed in pt compared to controls. the at group was significantly older, with higher bmi, lower quality of life and higher depression scores than the pt group. discussion: pt is characterised by localised mechanical hyperalgesia and greater mental toughness. the evidence of central sensitization in pt and at differs from that in the upper limb, suggesting a need to consider different mechanisms underlying the reported pain and disability, and likely different approaches to management. caution is required in drawing inferences due to small participant numbers, necessitating confirmatory replication studies. references: 1. rolke, et al. pain, 123, 231–243. 2006 21 s af. j sports med vol. 28 no.2 supplement 2016 o22: immediate effects of one session of extracorporeal shock wave therapy on the elasticity of tendon in athletes with patellar tendinopathy zj zhang 1 , gyf ng 2 , wc lee 2 , sn fu 2 1 luoyang orthopedic hospital of henan province, orthopedic hospital of henan province, luoyang, china; 2 department of rehabilitation sciences, the hong kong polytechnic university, hung hom, kowloon, hong kong, china. presenting author e-mail address: amy.fu@polyu.edu.hk introduction: patellar tendinopathy (pt) is one of the most common sport injuries in jumping athletes. changes in the tendon elasticity stiffness have been detected in athletes with pt. extracorporeal shockwave therapy (eswt) was used to reduce pain among athletes with pt. however, it is not known whether the reduction in pain induced by eswt is associated with the modulation of the tendon elasticity. purposes: to examine the immediate effects of eswt on the elasticity of the patellar tendon; and to explore the possible relationships between the changes in tendon resilience mechanical properties induced by 1-session of eswt and the intensity of activity-related pain. methods: a single-blinded randomized controlled trial methods: thirty-six male athletes aged between 18 and 32 with pt for more than 3 months were recruited from local basketball and volleyball teams. the subjects were randomized into eswt and sham groups. eswt was delivered at an intensity of maximum tolerable pain in the eswt group.in the eswt group received one session of eswt at their maximum tolerable pain supersonic shearwave imaging (ssi) was used to measure tendon elasticity shear modulus. intensity of pain during single-legged declined-squat were acquired at preand immediately post-intervention results: significantly greater reduction in the tendon shear elastic modulus was detected in the eswt group compared with the sham group (by 24.7% and 8.0% in the eswt and sham groups, respectively; p<0.05)). the patellar tendon shear elastic modulus was significantly reduced by 24.7% and 8.0 % in the eswt and sham groups, respectively. in the eswt group, the change in the tendon shear elastic modulus was related to the change in the intensity of squatting pain and the composite change in the knee range and squatting pain (r= 0.52, and 0.59, respectively; all p<0.05). conclusions: these findings suggest that possible association between the changes in the change of tendon elasticity mechanical properties and activity-related pain induced by 1-session of eswt in jumping athletes with pt. changes in tendon mechanical properties may be one of the treatment mechanisms induced by eswt in reducing the pain associated with pt athletes with pt. o23: pressure pain thresholds? don’t do what we did! ebonie k rio 1,2 , richard f ellis 3,4 , jono m henry 3 , victoria r falconer 3 , zoltan s kiss, jill l cook 1,2 , jamie e gaida 5,6 1 college of science, health and engineering, la trobe university, australia; 2 australian centre for research into injury in sport and its prevention (acrisp), federation university; 3 department of physiotherapy, school of clinical sciences, auckland university of technology, auckland, new zealand; 4 health and rehabilitation research institute, faculty of health and environmental sciences, auckland university of technology, auckland, new zealand; 5 university of canberra research institute for sport and exercise (ucrise); 6 discipline of physiotherapy, university of canberra, australia. presenting author e-mail address: e.rio@latrobe.edu.au introduction: pain-pressure thresholds (ppt) are used to study peripheral and central pain processing among individuals with tendinopathy. however, pathological tendon changes may exist without pain. there are no studies that separate people with asymptomatic tendon pathology, those with a history of tendon pain and controls (no history of pain and no tendon pathology on imaging.) 22 s af. j sports med vol. 28 no.2 supplement 2016 methods: this observational study was part of a larger study. in this component we compared ppt between individuals with and without asymptomatic tendon pathology, and between individuals with and without a past history of tendon pain. the patellar, achilles and supraspinatus tendons of 130 participants were deemed structurally normal or abnormal with ultrasound. ppt was determined using a digital algometer at 40kpa/sec at the patellar tendon, quadriceps muscle, l3 spinous process and deltoid insertion. results: two people were excluded for reporting pain history that was not related to tendon therefore 128 people were included in this study. original data analysis was conducted that (incorrectly) included asymptomatic pathology in the control group and compared with those with a history of tendon pain. when these groups were separated, it was found that asymptomatic tendon pathology was associated with increased ppt (p=0.000, n=7 pathology, n=92 controls) compared with controls. this analysis was also conducted with matched pairs due to the different group numbers (matched for bmi, age and sex but blinded to ppt data) and found to remain significant (p<0.004, n=7). those with a history of patellar tendon pain appeared to have decreased ppt until the asymptomatic pathology were removed from analysis, that is, the asymptomatic group artificially inflated the ppts of the control group leading to the incorrect conclusion that those with a history of patellar tendon pain remained peripheral sensitized. in fact, there was no difference between controls and those with a past history of tendon pain. discussion: ppts in the literature show large ranges for normal populations pathology and pain appear to influence ppt results. future research should consider the individual effects of pathology and pain and build on this pilot study. these findings point toward central nervous system adaptations (but perhaps not in the expected direction). identifying factors that might protect people from experiencing pain despite the presence of pathology, and the features of people who have successfully recovered from tendon pain advances our understanding of this painful condition. o24: interrogating the role of angiogenesis genes on musculoskeletal soft tissue injury risk m rahim 1 ; cj saunders 2 ; a gibbon 1 ; el khoury ly 3 , raleigh sm 4 , ribbans wj 4 ; m posthumus 1 ; j gamieldien 2 ; m collins 1 and av september 1 1 division of exercise science and sport medicine, university of cape town, cape town, south africa, 2 south african national bioinformatics institute, university of the western cape, cape town, south africa; 3 school of biological sciences, university of essex, colchester, united kingdom; 4 division of health and life sciences, university of northampton, northampton, united kingdom presenting author e-mail address: masouda.rahim@gmail.com introduction: angiogenesis is a fundamental component of the matrix remodelling pathway with a fundamental role in the healing and adaptive response. to date, variants within the genes encoding vascular endothelial growth factor (vegfa) and kinase insert-domain receptor (kdr) have been implicated with risk of anterior cruciate ligament (acl) ruptures [1]. the aim of this study was to investigate genetic variants in angiogenesis genes with risk of achilles tendinopathy (ten) in two independent populations (south african (sa) and british (uk)). methods: a genetic-association study was conducted on a total of 120 sa & 130 uk asymptomatic controls (con) and 108 sa & 87 uk participants with achilles tendinopathy (ten). all participants were genotyped for five functional polymorphisms in vegfa (rs699947, rs1570360, rs2010963) and kdr (rs1870377 and rs2071559). genotype frequency distributions were compared between the groups and haplotypes were also inferred. in order to refine the previously implicated genomic regions in vegfa and kdr, whole exome sequencing (wes) was performed on 10 cases and 10 controls, representative of extreme phenotypes, using the illumina hiseq 2000 platform (agilent v5 +utr). results: the main finding of this study was the association of the vegfa a-g-g inferred haplotype with increased risk of ten in the sa group (15% con vs 20% ten, p=0.048) and the combined sa+uk group (14% con vs 20% ten, p=0.009). additionally, the vegfa rs699947 cc genotype was independently associated with reduced ten risk in the sa group (32% con vs. 17% ten, p=0.019, or: 2.30, 95% ci: 1.14-4.64). preliminary analysis of the wes data highlighted twenty-three 23 s af. j sports med vol. 28 no.2 supplement 2016 genetic variants between the vegfa and kdr genes, of which 4 variants show a greater than 25% allele frequency difference between groups. discussion: these novel findings implicating the vegfa gene with ten risk provide preliminary evidence highlighting the potential biological significance of the angiogenesis signalling pathway in the aetiology of achilles tendinopathy. additional investigation of the wes data is currently underway to investigate the novel variants further. references: 1. rahim et al, j orthop res, 32(12):1612-1618, 2014 o25: microvascular volume in symptomatic achilles tendons is associated with visa-a score, but does not predict esw-induced intrinsic tendon tenderness sfe praet 1 , jh ong 1 , c purdam 2 , m. welvaert 3 , g lovell 1 , l dixon 2 , j gaida 4 , s manzanero 1 , n vlahovich 1 , d hughes 1 and g waddington 1 dept of 1 sport medicine and 2 physiotherapy, australian institute of sport, canberra, australia, dept of physiotherapy, 3 ucrise, university of canberra, canberra, australia, 4 discipline of physiotherapy, university of canberra, canberra, australia. presenting author e-mail address: stephan.praet@ausport.gov.au introduction: in the continuum model of tendon pathology, the role of neovascularisation for explaining pain and function is still poorly understood. a recent study suggests that standard power doppler ultrasound (pdu) has insufficient sensitivity to reliably assess the level of neovascularisation in tendons 1 . in accordance, the aim of this study was to study the association between contrastenhanced ultrasound (ceu) based microvascular volume (mv), visa-a scores and intrinsic achilles tendon (at) tenderness as assessed by a novel non-invasive intrinsic dolorimetry methodology. methods: after completing a visa-a questionnaire, real-time harmonic ceu measurements (aplio 500, toshiba medical systems, australia) of the mv of the at mid-portion using perflutren lipid microspheres (definity®,lantheus medical imaging, australia) contrast agent were taken in 20 patients (13 men/7 women, age: 44±8 yrs, bmi:24.4±3.3 kg.m-2) with clinical symptoms (duration 54±90 months) of unior bilateral achilles tendinopathy. intrinsic tendon tenderness was assessed by applying ultralow doses (0.01-0.3 mj.mm-2 at 1 hz) of single focused extracorporeal shock waves (esw, duolith sd1, f-sw probe, storz medical ag, switzerland) to the skin overlying the dorsal side of the achilles tendon. esw detection threshold (esw-dt) was determined for a total of seven 1-cm at sections in disto-proximal direction from its insertion. linear mixed model (lmm) analysis using ‘r’ 2 was used to determine the association between mv, visa-a and esw-dt for both symptomatic and asymptomatic ats (n=39). results: lmm analysis shows a significant association between visa-a and mv (b=-50.1, 95%ci=[79.9;-23.0], p=0.0015) as well as symptom duration (b=-24.0, 95%ci=[-36.1;-11.2], p=0.001). no significant association was found between mv and esw-dt in the mid-portion of the at. discussion: the variation in intrinsic at tenderness as assessed by esw cannot be explained by the variation in achilles tendinopathy associated hypervascularity. nevertheless, in contrast to previous high-quality pdu-studies 3,4 , our results indicate that hypervascularity of the at mid-portion as assessed by ceu is moderately associated with increased at pain and poorer at function as assessed by visa-a. in accordance, ceu-based microvascularity measurements have potential clinical application to objectively assess and monitor changes in tendinopathy-related pain and function throughout the course of a rehabilitation program or following a therapeutic intervention. references: 1. j. pingel et al. am j sports med. 2013 oct;41(10):2400-8. 2. r core team (2015). r: a language and environment for statistical computing. r foundation for statistical computing, vienna, austria. url https://www.r-project.org/). mailto:stephan.praet@ausport.gov.au https://www.r-project.org/ 24 s af. j sports med vol. 28 no.2 supplement 2016 3. rj de vos et al. am j sports med. 2007 oct;35(10):1696-701. 4. s. de jonge et al. scand j med sci sports. 2014 oct;24(5):773-8 o26: plantaris excision and achilles tendon scraping is associated with reduction in pain and improvement in tendon structure in patients with midportion achilles tendinopathy lorenzo masci 1 ; hakan alfredson 1 ; dylan morrisey 2 1 pure sports medicine, london, united kingdom 2 centre for sports and exercise medicine, william harvey research institute, queen mary university of london, united kingdom presenting author e-mail address: lorenzo.masci@puresportsmed.com introduction: the plantaris tendon has recently been described as a possible important factor in midportion achilles tendinopathy. clinical 1 , histopathological 2 and surgical studies 3,4 lend support to this relationship. the aim of this study was to prospectively examine a larger number of surgical cases of mid-portion achilles with suspected plantaris involvement. methods: a prospective design was implemented using utc to examine structure and visa-a to study clinical results. all subjects had suspected plantaris involvement and had failed non-operative treatment. plantaris excision and ventral achilles scraping were performed on all subjects. twentythree tendons from 18 subjects (12 men and 6 woman) with a mean age of 39 years (range 26-56 years) were included. duration of symptoms ranged from 2 to 120 months. all patients were physically active consisting of 14 runners, 1 cricket player, 1 rugby player and 1 recreational walker. there were three elite athletes. results: at 6 months follow up, wilcoxon signed ranks test demonstrated a significant increase in mean visa a score (z = -3.726 p<0.001) from 58.1 (range 30-86) to 92.6 (range 69-100). in addition, there was a significant increase in mean aligned fibrillar structure of the tendon on utc (z = -4.0470 p<0.001) from 83.7% to 90.6%. however, kendall’s tau test revealed no correlation between improvements in visa a and aligned fibrillar structure (r = -0.209 p = 0.237). at 6 months, all subjects were satisfied with the procedure and 16 out of 18 subjects had returned to pre-injury levels. discussion: plantaris excision and scraping of the ventromedial achilles tendon seems to have potential to reduce pain and improve tendon structure in a larger cohort of subjects. however, there is no direct correlation between reduction in pain and improvement in structure. studies on a larger group of patients with longer follow up are required to confirm these findings on pain and structure. references: 1. masci l, spang c, van schie htm, alfredson h. how to diagnose plantaris tendon involvement in midportion achilles tendinopathy clinical and imaging findings. 2. spang c, alfredson h, ferguson m, roos b, bagge j, forsgren s. the plantaris tendon in association with mid-portion achilles tendinosis: tendinosis-like morphological features and presence of a non-neuronal cholinergic system. histolo histopathol 2013;28:623-632. 3. masci l, spang c, van schie htm, alfredson h. do plantaris tendon removal and achilles tendon scraping improve tendon structure? a prospective study using ultrasound tissue characterisation. bmj open sport exerc med 2015;1:e000005. 4. bedi h, jowett c, ristanis s, docking s, cook j. plantaris excision and ventral partendinous scraping in an athletic population. foot and ankle international 2016.v ol 37 (4): 386=389 25 s af. j sports med vol. 28 no.2 supplement 2016 o27: fat pad adjacent to tendinopathy: coincidental or causal? ella rose ward 1 , gustav andersson 2,3 , ludvig j. backman 2 , jamie e gaida 1,4 1 discipline of physiotherapy, university of canberra, canberra, australia; 2 department of integrative medical biology, section for anatomy, umeå university, umeå, se-90187, sweden; 3 department of surgical and perioperative science, section for hand and plastic surgery, umeå university, umeå, se-90187, sweden ; 4 university of canberra research institute for sport and exercise (ucrise), canberra, australia. presenting author e-mail address: jamie.gaida@canberra.edu.au introduction: is it a merely a curiosity that fat pads are found adjacent to the area of tendon affected by tendinopathy? we propose that fat pads share an intimate anatomical and functional relationship with their adjacent tendons, and may therefore be an important contributor to the pathogenesis of tendinopathy. methods: key papers addressing this topic were identified through a structured search of pubmed, cinahl and medline and web of science. the results were synthesised as a narrative review. results: large fat pads located adjacent to tendons correspond to sites commonly affected by tendinopathy. for example, kager’s fat pad is directly adjacent to the commonly injured area of the achilles tendon, while hoffa’s fat pad is directly adjacent to the commonly injured patellar tendon. direct neurovascular and fibrous connections between fat pads and tendons are consistently identified in anatomical studies. there is also evidence associating enlarged fat pads and fat padmediated angiogenesis with tendinopathy pathogenesis. finally, fat pads located adjacent to pathologic tendons exhibit elevated cytokine levels. these cytokines may influence the tendon via the pathways involved in meta-inflammation. discussion: fat pads are commonly overlooked in clinical research due to an inadequate understanding of their functional and biological significance in disease. the intimate anatomical and functional relationship between fat pads and tendons supports our hypothesis that fat pads may be a contributor to the pathogenesis of tendinopathy. the relationship is likely to be complex, and we hope this review will focus attention and stimulate research to improve our understanding of this important structure and its relationship with tendinopathy. o28: botulinum toxin a blocks the release of acetylcholine from tendon cells – a novel role for botox in treating tendinopathy? gustav andersson 1,2 , jialin chen 1 1 department of integrative medical biology, umeå university, sweden; 2 department of surgery and perioperative sciences, section of handsurgery presenting author e-mail address: gustav.andersson@umu.se introduction: botulinum toxin is considered the most potent biotoxin known to man. the toxin acts by blocking the release of acetylcholine (ach) causing paralysis of muscles. this mechanism has been used for more than two decades, in order to treat symptoms in conditions such as spastic paraesthesia, in products such as botox. bont/a binds to the sv2a receptor and is internalised into efferent neurons. following internalisation, it cleaves the membrane bound protein snap-25. when snap-25 is cleaved, vesicles containing ach are unable to fuse with the cell membrane and thus cannot release ach into the synaptic cleft.studies with varying results have been directed towards the muscles of tendons involved in tendinopathy.our group has shown that tendon cells produce and release ach, and this production is upregulated in tendinopathy.this study aimed to evaluate whether bont/a could be directed towards the tendon – and not the muscle – in order to treat tendinopathy by blocking the endogenously produced ach from tendon cells. methods: tendon cells cultured from the achilles tendon of healthy controls and patients diagnosed with tendinopathy were exposed to bont/a (dysport ® ) or nacl (control) for 24 hours. culture media was collected and an assay directed towards ach was used to measure the levels of excreted ach. 26 s af. j sports med vol. 28 no.2 supplement 2016 immunohistochemistry towards sv2a and snap25 were performed on the same cells. results: cultured tendon cells expressed sv2a and snap25 as visualised by immunohistochemistry. treating the cells with bont/a for 24h decreased the immunoreactivity of snap25. the ach-assay showed a significant, dose-dependent, decrease in the concentration of ach in the culture media following bont/a-treatment for 24 hours, as compared to nacl-treated controls. discussion: this study shows the expression of the machinery involved in ach release, and the receptors required for bont/a action. treating tendon cells with bont/a decreased the expression of snap25, which implies that it has been cleaved and inactivated. bont/a-treated cells excreted less ach in the culture media. as production of ach in tendon cells has been shown to be up regulated in tendinopathy, bont/a-treatment may be a tool in affecting the intrinsic pathways hypothesised by danielson and others, in the biochemical model of tendinopathy. by directing bont/a injections towards the tendon instead of into the muscle – as has been the paradigm in earlier studies – improved results may be achieved. o29: collagen genes and risk of carpal tunnel syndrome mc burger 1 ; s dada 1 ; f massij 1 ; hanli de wet 2 and m collins 1 1 division of exercise science and sport medicine, university of cape town, cape town, south africa; 2 life occupational health, life healthcare, south africa presenting author e-mail address: marilizecb@gmail.com introduction: carpal tunnel syndrome (cts) is one of the most common disorders treated by hand surgeons 1 . although the exact mechanism is poorly understood, tendon pathology has been suggested to play a role in the aetiology of this injury. previously, variants in genes encoding structural and functional tendon proteins, such as type v collagen, have been associated with cts 2 .the aim of this study was to determine whether variants within several other collagen genes are associated with cts in a coloured south african population. methods: participants with carpal tunnel syndrome (cts, n=103) as well as matched asymptomatic control participants (con, n=150) were genotyped for various collagen gene variants including col1a1 rs1800012 (g/t), col11a1 rs3753841 (t/c), col11a1 rs1676486 (c/t) and col11a2 rs1799907 (t/a). results: the tt genotype of col11a1 rs3753841 was significantly over-represented in the cts group (21.4%) compared to cts con group (7.9%) (p=0.004). furthermore, a trend for the t minor allele of col1a1 rs1800012 to be over-represented in the cts group (p=0.055) with a significant association in female participants (p=0.036) was observed. constructed inferred pseudo-haplotypes also suggest various gene-gene interactions between the investigated variants. discussion: these findings provide further information about the role of genetic risk factors as well as the role of collagen fibril variation, and the result thereof, in the aetiology of cts. these risk factors could potentially aid in the development of risk models aimed at identifying individuals at risk for developing this injury and strategies that target modifiable risk factors to mitigate the effect of nonmodifiable risk factors, such as the genetic risk, could potentially be developed to reduce incidence and morbidity of cts. references: 1. gancarczyk sm, strauch rj. carpal tunnel syndrome and trigger digit: common diagnoses that occur ‘hand in hand’. j hand surg am 2013;38:1635–7. 2. burger m, de wet h, collins m. the col5a1 gene is associated with increased risk of carpal tunnel syndrome. clin rheumatol 2014;34:767–74. 27 s af. j sports med vol. 28 no.2 supplement 2016 o30: disruption of tgfβ signaling in the scleraxis cell lineage – a genetic model of tendon degeneration guak-kim tan 1 , brian a. pryce 1 , doug r. keene 1 , john v. brigande 2 , ronen schweitzer 1,2 1 shriners hospital for children, portland, or, 97239-3095. 2 oregon health and science university, portland, or, 97239-3098. presenting author e-mail address: ronen@shcc.org we previously reported that disruption of tgfβ signaling in limb mesenchyme resulted in failure of tendon differentiation. to study additional roles of tgfβ signaling in tendon development and maturation we chose to disrupt tgfβ signaling in tenocytes after they assumed the tendon cell fate by using the tendon deletor scxcre to target the type ii tgfβ receptor. mutant pups (cko; tgfbr2 f/;scxcre) appeared normal at birth but exhibited movement difficulties and splayed limbs by p3. examination of the tendon reporter scxgfp signal revealed that tendon formation was not affected in cko embryos, but in post-natal stages, some tendons that appeared intact at birth were abruptly eliminated and other tendons retained structural integrity with a mosaic loss of tendon gene expression, including the scxgfp signal, in the majority of the tenocytes. lineage tracing revealed that these cells were derived from earlier scx-expressing cells, suggesting that the tendon cell fate was disrupted in cko tendons. interestingly, we found some indications for tenocyte dedifferentiation but no evidence for trans-differentiation of these mutant tenocytes. in addition, cko tendons also revealed varying degrees of tendon degradation. this mutant phenotype thus highlights an unexpected fragility of the tendon cell fate that may play a role in the etiology of tendinopathy. analysis of this phenotype may therefore be instrumental for identifying the molecular and cellular requirements for maintenance of the tendon cell fate. lineage tracing also revealed that the cells that expressed scxgfp in cko tendons were not descendants of the original tenocytes but rather, cells that were newly recruited into the tendon concurrent with the onset of the degenerative processes described above. consistent with a stem/progenitor origin of these cells, we found in them sporadic expression of stem/progenitor markers such as nucleostamin and sox9. interestingly, these cells adopted an aberrant morphology and a very large volume resulting in tendon matrix disruption in their vicinity. this is the first demonstration of active cell recruitment into a non-injured tendon that may be used to identify the origin and activation mechanisms for tendon stem/progenitor cells, but may also point to molecular and cellular processes that underlie the progression of tendinopathy. o31: a cross sectional study correlating ultrasound tissue characterisaton and shear wave elastography in normal and tendinopathic achilles tendons bhavesh d kumar 1 , william wynter bee 1 , catherine payne 2 1 institute of sport exercise & health (national centre for sport & exercise medicine), university college london, london, uk; 2 university of brighton, eastbourne, uk presenting author email address: bhavesh.kumar@ucl.ac.uk background: the often poor correlation between clinical symptoms, function, imaging features and histopathology of tendinopathy remains a considerable challenge in the scientific understanding and clinical management of the condition. novel ultrasound (us) imaging modalities may help bridge this gap. aim: this cross-sectional study of symptomatic mid-portion achilles tendinopathy (at) and asymptomatic achilles tendons aimed to investigate the relationship between tendon structural integrity as determined by ultrasound tissue characterisation (utc, utc imaging, the netherlands), stiffness as determined by shear wave ultrasound elastography (swue, acuson siemans), and clinical symptoms and function as determined by the visa-a questionnaire. methods: subjects from a university and affiliated clinic were invited to participate following ethical approval. all participants completed the visa-a questionnaire and underwent both utc and swue measurement of their mid-portion achilles tendons by two experienced technicians. the at group was confirmed by an experienced clinician. comparison of means and correlation statistics were calculated using spss v22, with statistical significance taken as p<0.05. mailto:ronen@shcc.org mailto:bhavesh.kumar@ucl.ac.uk 28 s af. j sports med vol. 28 no.2 supplement 2016 results: 34 participants (21 males, 13 females; mean age 43, sd 16) were recruited, offering 68 tendons. 18 participants with mid-portion achilles tendinopathy (at group) had a mean visa-a score of 74 (95% confidence interval 69-80) and 16 participants with no history of tendinopathy (norm group) had a mean visa-a score of 99 (ci 98-100). there was a significant difference between utc and swue measurements between the at group (echotype one 55%, ci 49-60; echotype two 35%, ci 31-38; swe velocity 7.9m/s, ci 7.3-8.4) and norm group (echotype one 71%, ci 68-73; echotype two 29%, ci 26-31; swe velocity 9.1.m/s, ci 8.6-9.6). there was good correlation between swue and visa-a score (r=0.6) and fair correlation between utc echotype 1+2 and visa-a score (r=0.39) across all participants. correlation between swue and utc was poor (r<0.4) when the entire group was considered and when the norm and at groups were separated. conclusion: both swue and utc appear able to distinguish symptomatic mid-portion achilles tendinopathy from normal tendons. swue showed stronger correlation with visa-a score than utc, potentially indicating greater relevance of estimating mechanical properties of tendons in facilitating clinical management of achilles tendinopathy. original research 64 sajsm vol. 28 no. 3 2016 posture and isokinetic shoulder strength in female water polo players k d aginsky, phd; c tracey, bhsc hons biokinetics; n neophytou, msc (med) centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: k d aginsky (kerithaginsky@gmail.com) water polo is a high-intensity intermittent aquatic sport which places large physical demands on the participants[1] and involves repetitive physical motions that are common to swimming and baseball pitching.[2] water polo consists of four quarters, where two teams of seven players per side attempt to score goals by throwing the ball into their opponents' goal. water polo is played in a pool measuring either 20 m by 10 m or 30 m by 20 m, with a depth of 1.8 m. during the throwing action, the mechanics are similar to those of baseball pitching.[2] this forms a large component of the sport and involves the combination of muscle strength and coordination between the upperand lower extremities. however, as the sport is played in a pool, unlike baseball or cricket, there are no stabilising surfaces[3] from which to throw the ball. this, in turn, may increase the total forces on the joints at the shoulder complex.[2] water polo players continuously place their shoulder joints under recurring stress while performing repetitive overhead movements which can cause joint instability and muscular imbalances between the internal rotator (ir) and external rotator (er) muscles.[2,4] radaelli et al. [5] claims that this imbalance may occur due to the more frequent contraction pattern of the ir muscles compared to the er muscles. the cumulative loads placed on the posterior shoulder joint during deceleration during throwing in water polo can result in posterior stiffness associated with a greater imbalance between the internal and external rotator cuff muscles and translation of the humeral head, thus predisposing the athlete to shoulder injury.[2] furthermore, during freestyle swimming in water polo, the head is more often out of the water and the ball positioned directly in front of the athlete[2,6] which places a heavy load on the shoulder joint and surrounding soft tissue.[7] in addition, while swimming freestyle in water polo, the dominant stroke action is that of head-up. this requires an altered form of traditional freestyle with the head out of the water and the arm elevation more exaggerated, as the arms are keeping the ball in front of the face of the player. furthermore, to increase the force of the throw when shooting, a greater amount of external rotation and abduction are required, [6,8,9] enabling females for example to reach a speed to 16.8m/s.[10] the amount of strength required to perform these forceful movements predispose the shoulder region to instability and muscle imbalance between the internal and external shoulder rotators.[11] lynch et al. [12] reported that swimmers and overhead athletes often develop swimmer’s shoulder which encompasses a variety of pathological injuries, such as rotator cuff tendinitis, shoulder instability and shoulder impingement. a disparity in muscle balance may lead these athletes and swimmers to develop an increased risk of postural abnormalities and subsequently, to predispose them to shoulder injuries. however, there is limited evidence regarding the presence of muscle imbalances and postural abnormalities in water polo players. it has been established that if a malalignment in the posture is present, it may indicate that there is a muscle imbalance; thus postural orientation may play a role in sport performance.[13] a study by gradidge et al. showed that there is a relationship between poor shoulder posture and shoulder injury in water polo players.[14] the limited research into posture and shoulder muscle strength in water polo players makes this study important in assisting with the identification of these muscle imbalances and specific postural characteristics, which will be useful in future studies. background: being overhead athletes, water polo players can present with muscular imbalances of the shoulder, between the internal rotators (ir) and external rotators (er), leading to changes in posture and an increased risk of injury. objectives: to assess posture and isokinetic shoulder strength of female club-level water polo players. methods: a descriptive study assessing posture and isokinetic strength of the ir and er shoulder muscles in 15 female clublevel south african water polo players (age: 21.3 ± 1.5 years) was conducted. posture was assessed using a posture grid. isokinetic shoulder rotator muscle strength was tested over five repetitions concentrically and eccentrically at 60°/sec using a biodex system 3 isokinetic dynamometer. the bilateral, reciprocal and functional dynamic control ratios (dcr) were calculated. results: typical postures noted were a forward head, rounded shoulders, increased thoracic spine kyphosis, elevated non-dominant shoulder and mild scapula winging. the mean concentric reciprocal ratios for the dominant (52.2 ± 7%) and non-dominant (51.9 ± 6.4%) sides indicated er muscle weakness. dcr values were within normal limits for the group. (d: 0.75 ± 0.2 and nd: 0.75 ± 0.1). conclusion: there is a trend for these female water polo players to have rounded shoulders and forward head postures, as well as er muscle strength weakness, the combination of which could predispose the athletes to shoulder injury. keywords: dynamic control ratio, shoulder injury, rounded shoulders, reciprocal ratio s afr j sports med 2016;28(3):64-68. doi: 10.17159/2078-516x/2016/v28i3a438 mailto:kerithaginsky@gmail.com http://dx.doi.org/10.17159/2078-516x/2016/v28i3a438 original research sajsm vol. 28 no. 3 2016 65 methods this was a descriptive study assessing the posture profiles and concentric and eccentric ir and er shoulder muscle strength in 15 club-level female water polo players, aged between 18 and 25 years. dominance was assessed as the preferred throwing arm. ethical clearance was obtained from the human research ethics committee of the university of the witwatersrand and written informed consent from each participant prior to testing. all participants were informed of the risk of muscle soreness, which is normal during the maximal isokinetic testing, prior to signing the informed consent. the study excluded any prospective participants with a shoulder, neck or back injury at the time of the testing, those who had suffered from a shoulder injury in the preceding six months, and those who had previous shoulder surgery, which would affect muscle strength output. posture assessment the participants were asked to wear appropriate clothing so that the natural curves of the body could be seen. the subjects were asked to stand in their normal, comfortable anatomical position with the postural grid behind them and not to correct any postural abnormalities. a plumb line was used as a reference point in assessing the participant’s posture. each participant was analysed by an experienced therapist from an anterior, posterior and lateral view using the posture grid. anterior and posterior views included the assessment of shoulder height, scoliosis, scapula winging and lateral pelvic tilting. the lateral assessment included head position, shoulder orientation, lumbar and thoracic curvatures, and anterior or posterior pelvic tilting. the various components were rated by one experienced researcher on the following scale: 0 = no abnormality, 1 = slight, 2 = moderate, 3 = severe. isokinetic assessment isokinetic strength was assessed using a biodex system 3 isokinetic dynamometer (biodex medical systems, shirley, new york). maximal strength testing of the ir and er shoulder muscles was performed concentrically and eccentrically in the modified neutral position. prior to testing, participants were warmed up on an arm ergometer (technogym, cesena, italy) for five minutes. participants were seated, with their upper body stabilised by means of stabilisation straps to prevent unwanted movement. the axis of rotation was aligned as the line from the olecranon process through the humerus to the acromion process, ensuring that the subject had full, safe range of motion. the participant was shown what will be required from them in the testing procedure. testing included a standard biodex strength testing protocol of five maximal concentric repetitions at 60˚/sec, followed by five maximal eccentric repetitions at 60˚/sec. the testing was performed on both of the subject’s arms. the following muscle strength ratios were calculated using the internal and external rotator muscle peak torque (pt) values:  reciprocal ratio (%): (external rotator pt / internal rotator pt) x 100  dynamic control ratio (nm): eccentric external rotator pt / concentric internal rotator pt  bilateral deficit (%): (dominant pt – non-dominant pt) / dominant pt x 100  pt to body weight (nm/kg): pt / body weight statistical analysis all data were descriptively analysed and are represented as means and standard deviations. a student’s t-test was used to assess bilateral differences in the strength results. significance was accepted at p<0.05. results demographic results fifteen female club-level water polo players with a mean age of 21.3 ± 1.5 years were tested. they were 1.65 ± 0.60 m tall and weighed 67.1 ± 8.2 kg. the majority of the participants were right-side dominant (n=14). posture figure 1 shows the head and shoulder orientation, characterised as slight, moderate or severe. most of the athletes displayed a slight forward head posture (n=11), whilst all had either a slight or moderate forward or rounded shoulder posture. fourteen athletes had shoulder height discrepancies, with the majority having a slightly elevated non-dominant shoulder (n=9). furthermore, six players had slight scapula winging and one had moderate scapula winging. nine players were observed to have slight thoracic kyphosis and four athletes displayed slight scoliosis. fig 1. upper body postural profile of 15 club-level female water polo players. d: dominant; nd: non-dominant isokinetics peak torque (pt) table 1 below shows the bilateral pt results for both concentric and eccentric tests for the water polo players. the er peak torque values were lower than the ir peak torque values for both concentric and eccentric tests. there were no statistically significant bilateral differences found for either concentric (p = 1.103; p = 0.081) or eccentric peak torque values (p = 1.199; p = 0.207) for the internal and external shoulder rotators respectively. original research 66 sajsm vol. 28 no. 3 2016 peak torque/body weight ratio (pt/bw) pt/bw (nm/kg) values were recorded for both concentric and eccentric contractions (table 2). there were no bilateral differences for the concentric ir pt/bw (p = 0.143) and concentric er pt/bw (p = 0.136) respectively. the pt/bw ratios on the dominant and non-dominant sides were also similar when the eccentric ir (p = 0.311) and er pt/bw ratios (p = 0.244) were assessed. reciprocal ratio the mean reciprocal ratios were calculated for both concentric and eccentric internal and external shoulder rotation on the dominant and non-dominant sides (table 3). there were no bilateral differences for either the concentric (p = 0.914) or eccentric reciprocal ratios (p = 0.652). although the mean values only show a slight er muscle weakness, the range indicates that some athletes had a more pronounced er muscle weakness for both concentric (40 to 62 %) and eccentric ratios (n = 4: 55 to 60 %). for the non-dominant side n = 11 had a concentric ratio below 62% and n = 6 for an eccentric ratio below 62%. bilateral deficit the bilateral ratio was calculated for concentric and eccentric internal and external shoulder rotation muscles (table 4). the mean ratios were within normal limits for both the concentric and eccentric movement patterns and for both ir and er muscle groups. however, when assessing the range there were athletes (con er: n = 8 and con ir: n = 6; ecc er: n = 9 and ecc ir: n = 5) who showed bilateral imbalances. dynamic control ratio (dcr) the dcr for the dominant and non-dominant sides are shown in table 5. there were no bilateral differences between the dominant and non-dominant arms (p = 0.984). the range, however, indicates a high variation between the results of the table 1. concentric and eccentric peak torque external and internal shoulder rotation values for female, club-level water polo players at 60 o/s of dominant and non-dominant sides (n=15) muscles dominant pt (n=15) non-dominant pt (n=15) p mean ± sd range mean ± sd range con ir (nm) 33.0 ± 6.9 22.5 – 46.1 29.6 ± 5.7 20.4 – 40.3 0.103 con er (nm) 17.1 ± 3.5 12.0 – 23.7 15.2 ± 3.0 10.6 – 21.2 0.081 ecc ir (nm) 34.9 ± 5.7 24.9 – 44.3 32.7 ± 6.1 24.6 – 43.4 0.199 ecc er (nm) 24.0 ± 5.1 16.1 – 32.7 21.9 ± 4.6 14.7 – 29.0 0.207 pt: peak torque; con: concentric; ecc: eccentric, ir: internal rotators, er: external rotators, min: minimum, max: maximum table 2. dominant and non-dominant mean concentric and eccentric peak torque to body weight ratios at 60 o/s in female, club-level water polo players (n=15) muscles dominant pt/bw (n=15) non-dominant pt/bw (n=15) p mean ± sd range mean ± sd range con ir (nm/kg) 0.49 ± 0.1 0.32 – 0.67 0.44 ± 0.1 0.29 – 0.58 0.143 con er (nm/kg) 0.25 ± 0.0 0.18 – 0.33 0.22 ± 0.0 0.16 – 0.32 0.136 ecc ir (nm/kg) 0.52 ± 0.1 0.39 – 0.67 0.49 ± 0.1 0.38 – 0.59 0.311 ecc er (nm/kg) 0.36 ± 0.1 0.23 – 0.59 0.32 ± 0.1 0.22 – 0.41 0.244 pt: peak torque; con: concentric; ecc: eccentric, ir: internal rotators, er: external rotators, min: minimum, max: maximum table 3. dominant and non-dominant mean concentric and eccentric reciprocal ratios at 60 o/s in female, club-level water polo players (n=15) ratio dominant (n=15) range (%) non-dominant (n=15) range (%) p con/con (%) 52.2 ± 7.0 40 to 65 51.9 ± 6.4 40 to 62 0.914 ecc/ecc (%) 69.9 ± 16.0 51 to 107 67.3 ± 10.9 55 to 93 0.652 con/con; concentric/ concentric, ecc/ecc: eccentric/ eccentric table 4. concentric and eccentric mean bilateral ratios for internal and external shoulder rotation at 60 o/s in female club-level water polo players (n=15) contraction ir (n=15) range (%) er (n=15) range (%) con (%) 9 ± 11 -6 to 33 10 ± 6 -3 to 21 ecc (%) 6 ± 10 -14 to 28 5 ± 30 -80 to 49 con; concentric/ concentric, ecc: eccentric/ eccentric, ir: internal rotators, er: external rotators table 5. dominant and non-dominant mean dynamic control ratios at 60 o/s in female club-level water polo players (n=15) ratio dominant (n=15) range non-dominant (n=15) range p dcr 0.75 ± 0.21 0.45 to 1.32 0.75 ± 0.12 0.57 to 0.92 0.984 dcr: dynamic control ratio original research sajsm vol. 28 no. 3 2016 67 participants (0.57 to 0.92). discussion the sport of water polo involves short bouts of high-intensity play with repetitive cyclic arm motions.[2] the assessment of water polo players’ shoulder strength can assist in determining whether they have sufficient muscle strength to perform these tasks or whether there is a possible predisposition to injury.[15] the demographic characteristics seen in the 15 female clublevel water polo players are comparable to other research on elite water polo players of a similar age.[16] the majority of the participants presented with a forward head and rounded shoulder posture while nine also had slight thoracic spine kyphosis. these are common postures in swimmers and overhead athletes where they present with shortened cervical extensors and lengthened cervical flexors.[3] furthermore, the rounded shoulder posture may also indicate the presence of muscular imbalances surrounding the shoulder girdle, with the anterior chest muscles, such as the pectoralis major and minor being shortened. the posterior thoracic muscles, namely, the middle and lower trapezius and rhomboid muscles, were shown to be weak and lengthened. an imbalanced upper extremity posture would negatively affect the position of the glenohumeral joint and, combined with possible thoracic muscle weakness and fatigue, may predispose an individual to injury.[3,12] the majority of the athletes presented with an elevated nondominant (n=9) or dominant (n=5) shoulder. the presence of shoulder height discrepancy may be the result of a superiorly translated humeral head due to the lack of scapula stabilisation[17] as seen by the thoracic kyphosis, rounded shoulder posture and winged scapulae. superior translation of the humeral head can lead to a narrowing of the subacromial space and predisposition to rotator cuff impingement, which is due to postural imbalances seen in overhead athletes from weak external rotators compared to internal rotators.[18] the water polo players had lower peak torque values for the concentric and eccentric er muscles compared to the ir muscles. similarly, when peak torque was normalised to body weight, the ir muscle strength was greater than the er muscle strength. these findings are further indicated by the weakness seen in the er muscles relative to the ir muscles in the reciprocal ratio. these results are lower than previously found in the assessment of the peak torque to body weight ratio in asymptomatic overhead athletes[19] and reciprocal ratio in water polo players. however, they were previously assessed at 30o/sec, which could account for the differences.[2] it is important to also assess the comparison of the eccentric er muscle strength relative to the concentric ir muscle strength in overhead athletes whose sport involves throwing. the concentric muscular contraction is important for the acceleration phase of throwing, whilst the eccentric muscle action is vital in the deceleration phase of throwing.[15] thus the dcr evaluates the concurrent work of the muscles in terms of the strength of the eccentric er strength relative to the concentric ir strength. furthermore, this synchronisation of opposing muscles assists in the prevention of injury. the dcr for the group showed no bilateral differences (d: 0.75 ± 0.21 and nd: 0.75 ± 0.12); however, the large range on both sides indicates that there is a percentage of water polo athletes who show eccentric er muscle weakness (d: 0.45 to 1.32 and nd: 0.57 to 0.92). these results demonstrate lower values than those found in previous studies, which were performed on non-water polo players.[18] the mean bilateral ratios for the group were within normal limits for both the concentric and eccentric movement patterns of the ir and er muscle groups; however, when assessing the range, there were athletes who exhibited bilateral imbalances (con ir: -6 to 33%; con er: -3 to 21%; ecc ir: -14 to 28% and ecc er: -80 to 49%). these results indicate that within the group tested there are athletes who are possibly predisposed to injury. similar findings in previous research , also found the dominant arm was stronger than the non-dominant arm in water polo players.[2] in addition, it has been found that athletes involved in overhead sports have a larger dominant arm than the non-dominant arm.[18] it is possible that this can be attributed to water polo, which is an asymmetrical sport, using mainly the dominant arm for throwing and shooting for goal. these muscle imbalances may be associated with the shoulder elevation found in the majority of water polo players; however, this relationship needs to be further investigated. thus the combination of postural abnormalities of the upper extremity and muscle weakness of the external shoulder rotators could predispose these athletes for developing shoulder injuries. conclusion female water polo players present with postural abnormalities, which include rounded and elevated shoulders, thoracic spine kyphosis and a forward head posture. these abnormalities are possibly associated with the concentric and eccentric weakness found in the external rotator muscles relative to the concentric internal rotator muscles. these muscle imbalances and postural abnormalities could predispose the water polo players to shoulder injuries. acknowledgements: the authors would like to thank the participants of the study. conflicts of interest: there are no conflicts of interest related to this study. references 1. mota n, ribeiro f. association between shoulder and proprioception and muscle strength in water polo players. isokinet exerc sci 2012;20(1):17-21. doi: 10.3233/ies-2011-0435. 2. mcmaster wc, long sc, caiozzo vj. isokinetic torque imbalances in the rotator cuff of the elite water polo player. am j sports med 1991;19(1):72-75. doi: 10.1177/036354659101900112 3. houglum p. therapeutic exercise for musculoskeletal injuries. 3rd ed. 2010. champaign, il: human kinetics 4. smith hk. applied physiology of water polo. sports med 1998;26(5):317-334. doi: 10.2165/00007256-199826050-00003. 5. radaelli r, bottaro m, weber f, et al. influence of body position on shoulder rotator muscle strength during isokinetic assessment. isokinet exerc sci 2010;18(3):119-124. doi: 10.3233/ies-2010-0369 6. webster mj, morris me, galna b. shoulder pain in water polo: a systematic review of the literature. j sci med sport 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water polo players. aust j sci med sport 1990;22(9):205-220. 12. lynch ss, thigpen ca, mihalik jp, et al. the effects of an exercise intervention on forward head and rounded shoulder postures in elite swimmers. br. j. sports med. 2010;44(5):376-381. doi: 10.1136/bjsm.2009.066837 13. sweeting k, mock m. gait and posture assessment in general practice. aust. fam. physician 2007;36(6):398-401,404-405. pmid 17565395 14. gradidge p, neophyton n, benjamin n, et al. the injury and posture profiles of male high school water polo players in johannesburg, south africa. afr. j. phys. health educ. recr. dance. 2014;20(1):179-188 15. ellenbecker ts, davies gj. the application of isokinetics in testing and rehabilitation of the shoulder complex. j. athl. train. 2000;35(3):338350. doi: 10.1016/b978-1-4377-2411-0.00025-3 16. alcaraz pe, abraldes ja, ferragut c, et al. throwing velocities, anthropometric characteristics, and efficacy indices of women's european water polo subchampions. j strength cond. 2011;25(11):30513058. doi: 10.1519/jsc.0b013e318212e20 17. tovin bj. prevention and treatment of swimmer's shoulder. n am j sports phys ther 2006;1(4):166-175. pmcid: pmc2953356 18. van cingel r, kleinrensink gj, mulder p, et al. isokinetic strength values, conventional ratio and dynamic control ratio of shoulder rotator muscles in elite badminton players. . isokinet exerc sci 2007;15(4):287-293. 09593020 19. zanca gg, oliveira ab, saccol mf, et al. functional torque ratios and torque curve analysis of shoulder rotations in overhead athletes with and without impingement symptoms. j. sports sci. 2011;29(15):16031611. doi: 10.1080/02640414.2011.608702. original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the relationship between core stability and athletic performance in female university athletes m de bruin,1 msc; d coetzee,1 phd; r schall,2 phd 1 department of exercise and sport sciences, faculty of health sciences, university of the free state, bloemfontein, south africa 2department of mathematical statistics and actuarial science, faculty of natural and agricultural sciences, university of the free state, bloemfontein, south africa corresponding author: m de bruin (debruinm@ufs.ac.za) core stability has been studied for more than 40 years and has become fundamental to training programmes for performance enhancement in diverse sporting codes.[1] however, the two fundamental concepts of core strength and core stability have generally not been distinguished.[1] akuthota and nadler defined core strength as the involvement of the anatomical structures around the lumbar spine in the maintenance of functional stability.[2] this definition differs from the usual notion of strength in athletes proposed by lehman as a maximum force produced by a muscle group at a certain velocity.[3] the training of core strength includes several repetitions performed at a high load with core muscle tension.[4] core strength is vital for sport performance and should be considered as an important component to determine core stability.[5] core endurance can be defined as the potential of the core muscles to avoid fatigue during continuous low-load activities.[6] core motor control is the activation of core muscles in a specific task controlled by the central nervous system.[6] consensus on how these different components should be defined and assessed is lacking. no gold-standard measurement has been described or suggested for the evaluation of core stability.[7] therefore, core stability assessment should consist of a battery of tests that evaluates various components of the core, depending on the demand of the task.[8] knowledge of functional core stability has led to the ability to classify and identify the components that affect core muscle function. the core muscles are important for dynamic stabilisation.[9] research on core stability exercise programmes and the associated improvement of athletic performance is limited.[1] sharrock et al.[5] concluded from a pilot study that future research should attempt to establish the sub-categories involved in core stability and identify which are most important for individual sport codes. the aim of this study was to evaluate the relationship between core stability, including the sub-categories of strength, endurance and neuromuscular control (nmc), and athletic performance among female university athletes in hockey, netball, running, soccer and tennis. methods participants and study design in the 2018/2019 season, 122 female athletes were members of the first hockey, netball, running, soccer and tennis teams at the university of the free state (ufs) in bloemfontein, south africa. all these athletes were invited to participate in the study. subjects were excluded from the study if they (i) had an acute, medically diagnosed injury that required medical treatment during the preceding three months, (ii) had an illness on the day of testing, or (iii) refused informed consent to participate in the study. data were collected and recorded using a scoring sheet. the scoring sheet indicated the core stability and athletic performance tests, and the sequence of testing. testing of the various sport teams took place on different days as part of their periodisation in the off-season and pre-season, respectively. one week before testing, the participants were informed that on the day of testing they were not allowed to exercise. on the day of the testing, the participants did a 10-minute warm-up on a cycle ergometer and performed dynamic stretches. background: questions remain as to whether core stability represents single or multiple components, how to assess core stability, and if a relationship exists with athletic performance in different sporting codes. objectives: to investigate the relationship between core stability and athletic performance in female university athletes. methods: eighty-three female athletes (hockey, netball, running, soccer and tennis) participated in this quantitative, cross-sectional study. the isometric back extension (ibe), lateral flexion (lf) and abdominal flexion (af) tests were used to measure core strength and endurance. the core stability grading system using a pressure biofeedback unit was applied to measure core neuromuscular control (nmc). athletic performance was assessed using the 40 m sprint, ttest, vertical jump (vj) and the medicine ball chest throw (mbct). correlations between the core stability tests and the athletic performance tests were determined overall and separately by sport. the effect of core stability on athletic performance was analysed using ancova. results: overall for all sports, most correlations were weak (r=0.10–0.39), although there was a very strong correlation between lf (strength) and vj (r=0.90). when the sports were considered separately, there were moderate correlations (r=0.40–0.69) between core strength, endurance and motor control with certain athletic performance tests in all five sport codes. in runners, strong correlations (r=0.70–0.89) were observed between af (endurance) and vj, and in tennis players between ibe (strength) and the sprint. conclusion: correlations were found between core stability and athletic performance, although most correlations were negligible or weak. athletic performance in different sport codes is associated with different components of core stability. keywords: hockey, netball, running, soccer, tennis, functional stability s afr j sports med 2021;33:1-9. doi: 10.17159/2078-516x/2021/v33i1a10825 mailto:debruinm@ufs.ac.za http://dx.doi.org/10.17159/2078-516x/2021/v33i1a10825 https://orcid.org/0000-0001-6303-6631 https://orcid.org/0000-0002-3151-6582 https://orcid.org/0000-0002-4145-3685 original research sajsm vol. 33 no. 1 2021 2 ethical considerations approval to conduct the research was granted by the health sciences research ethics committee (hsrec) of the faculty of health sciences, university of the free state (reference number ufs-hsd2019/0447/2506). all participants provided their informed consent. core stability testing core strength tests as described by saeterbakken et al.,[10] the core strength of the global core muscles was measured using the biering-sørensen tests, which included isometric back extension (ibe), lateral flexion (lf) and abdominal flexion (af). the participants were required to contract their global core muscles to their maximum for three seconds. the explosive power output of the maximum volunteered contraction was measured using a tendo sports machine (tendo sports machines; trencin, slovak republic). each of the three respective core strength tests were performed three times with a one-minute rest between the attempts and three minutes of rest before performing the next test. the greatest mean force output in newtons (n) over three seconds for each test (ibe, lf and af) was used in further analyses. the biering-sørensen ibe test was assessed in a prone position on an exercise bed. the participant had to hold the prone position until failure.[11] the edge of the iliac crest was positioned on the tip of the bed while the arms were crossed over the chest. lastly, the body was in a straight position with the feet secured to the bed by the ankles.[11] during the lf test, the participant lay down horizontally with their legs and hip relaxed on the bed. the participants were not allowed to rest on their elbows while their feet were tied with a strap to the bed across their ankles. only the dominant side was assessed (facing upwards) and the nondominant arm was crossed over the chest.[10] for the af test position, the participant had to hold a 45° angle between their hips and the bed and the hips and knees were bent at 90° angle. the spine had to be held upright while the arms were crossed over the chest and their feet secured to the bed.[11] core endurance tests the same positions used to measure the core strength of the global muscles were used to assess the core endurance of the global muscles. to determine the endurance of the global core muscles, participants were required to contract these muscles to the maximum for as long as they could. a stopwatch was used to determine how long they could hold this contraction. a reliability coefficient of 0.97–0.99 has been reported for the bering-sørensen method.[11] all tests were terminated when the participant fell below the test position. core neuromuscular control (nmc) tests core neuromuscular control (nmc) was assessed using a welch allyn flexiport (hill-rom holdings inc.; chicago il, usa) pressure biofeedback unit. this was able to determine changes in pressure while the local and global core muscles aimed to stabilise the trunk during low-load limb movement.[12] an interclass correlation coefficient (icc) of 0.91 for test-retest reliability of the pressure biofeedback unit has been reported.[12] the wisbey-roth core stability grading system was used to classify the motor control component of core stability.[13] the participant lay in a supine position on an exercise bed. a pressure biofeedback unit was placed below the lower back and inflated to 40 millimetres of mercury (mmhg). the participant was instructed to maintain the pressure on the gauge while breathing regularly. this was considered as a grade 1 on the wisbey-roth core stability grading system.[13] if the participant failed to maintain the pressure they scored grade 0. the participant obtained a grade 2 if they were able to maintain the pressure on the gauge while performing single leg slides of the limbs. a grade 3 was scored if the participant was able to maintain the pressure while performing slow movements of the trunk. if they were able to maintain the pressure on the gauge while performing fast movements of the limbs, a grade 4 was recorded and a grade 5 was obtained with fast movements of the trunk and limbs against resistance. changes in the pressure greater than 10 mmhg were indicative of diminished core motor control. the next level was only determined only after the previous level had been successfully completed.[13] each activity level represented a level of core motor control.[14] the participant was allowed one trial on each level and was only progressed to the next level after successful core motor control of the previous level. scoring was the highest completed level where the instructed task was successfully completed with a change of less than 10 mmhg on the pressure biofeedback unit with a normal breathing pattern.[15] athletic performance testing agility test the t-test (icc=0.97)[16] was conducted to assess the participant’s agility in a forward, backward and lateral direction. the agility and direction changes performed during a t-test are used in a wide variety of sporting codes. optimal agility is critical to complete the course and change of direction within the shortest amount of time.[5] the time of the t-test (in seconds) was recorded using a stopwatch. four cones were used as markers for the t-test. on the cue of the timer, the participant sprinted 10 m from the start in a forward direction to touch the base of the cone, then sideshuffled 5 m to the left to touch the base of the cone. the participant then changed direction to the right and shuffled 10 m to touch the base of the cone, changed direction again to the left and shuffled 5 m to touch the base of the cone, and then ran 10 m backwards to the start. time was stopped when they passed the start. the participants completed three rounds and the best time to the nearest 0.1 seconds was recorded. speed test the 40 m sprint test (sprint) (icc=0.85)[17] was used to assess the participant’s lower extremity explosive power and speed.[18] participants had to cover a distance of 40 m as fast as possible. the time was recorded from the first movement of the extremities and terminated when the participant crossed the line. the participants completed three rounds after which the original research 3 sajsm vol. 33 no. 1 2021 fastest time to the nearest 0.1 seconds was recorded. lower extremity explosive power test the vertical jump (vj) was used to assess lower extremity explosive power. sports such as netball, soccer and tennis require good explosive power of the lower extremities to jump specific heights. the vertec (rogue fitness; columbus oh, usa) vj tester (icc=0.99)[19] was used to determine the vj height. the participant stood facing the wall and reached up with both hands. the standing reach distance was recorded at the top of the fingertips while the participant stretched their arms above their head, keeping their feet flat on the ground. the participant was instructed to stand perpendicular to the vertec with their body weight equally spread between the legs and feet and with the dominant side facing the wall. the participant was not allowed to perform a double bounce before the jump. the participant was allowed to bend the knees and then jump from both feet as high as possible and touch the vertec with the dominant hand. the participants completed three trials and the best height to the nearest 0.1 cm was recorded. upper extremity explosive power test the medicine ball chest throw (mbct) (icc=0.87–0.95)[20] was used to assess upper extremity strength and explosive power.[5] many sports require overhead activities such as throwing a ball or catching an object, and a good level of upper extremity explosive power is required for optimal performance during these movements.[5] the participant was instructed to stand in a kneeling position with knees bent at 90° and both hips in full extension. a distance of 10 m was measured out using a measuring tape. the 3 kg medicine ball was held with both hands in front of the chest. when the participant was ready, they could throw the ball vigorously as far forward as possible without falling forward or rocking back to gain momentum before the throw. each participant was granted a practice trial to ensure they understood how to perform the movement. if the movement was carried out properly without compensatory or trick movements, the distance of the first bounce was measured. the participants completed three trials and the best distance to the nearest 0.1 m was recorded. statistical analysis data were captured on a microsoft excel (microsoft office 2016) spreadsheet. further analysis was performed using the sas statistical software (sas institute inc.; cary, nc). data on core stability, namely ibe (strength), lf (strength), af (strength), ibe (endurance), lf (endurance), af (endurance), and core neuromotor control (nmc), and for the four tests of athletic performance (sprint, t-test, vj and mbct), were available for 83 athletes. the data on core strength, core endurance and core motor control were summarised using descriptive statistics. to assess the effect of core stability on athletic performance, both pairwise correlations and analysis of covariance (ancova) were carried out. correlations as described by scharrock et al.,[5] pearson correlation coefficients and associated p-values were calculated between the characteristics of core strength, core endurance and core motor control and the four tests of athletic performance. this was done overall for all participants and separately for each sport. correlations were referred to as ’negligible’ if their absolute value was in the range 0.00–0.10, ’weak’ (0.11–0.39), ’moderate’ (0.40–0.69), ’strong’ (0.70–0.89) and ’very strong ’ (0.90–1.00).[21] table 1. descriptive statistics for participants' core strength and core endurance: overall and by type of sport all sports (n=83) hockey (n=24) netball (n=16) runner (n=15) soccer (n=17) tennis (n=11) ibe (strength) (n) mean 1002 1056 1037 1024 1017 783 minimum 687 750 687 757 748 745 maximum 1517 1422 1517 1303 1517 540 ibe (endurance) (s) mean 149.7 143.9 97.8 198.8 140.2 185.9 minimum 50.0 50.0 55.1 84.0 72.0 135.0 maximum 149.7 143.9 97.8 198.8 140.2 185.9 lf (strength) (n) mean 799 858 799 773 824 667 minimum 565 586 639 565 625 625 maximum 1082 1082 1018 984 1018 701 lf (endurance) (s) mean 67.6 71.2 45.0 91.0 62.8 68.4 minimum 13.0 19.0 13.0 37.5 17.3 45.9 maximum 181.0 145.0 181.0 141.0 91.0 140.0 af (strength) (n) mean 897 958 906 859 941 736 minimum 646 646 684 687 695 690 maximum 1300 1274 1300 1188 1214 769 af (endurance) (s) mean 149.2 158.0 101.3 203.7 135.2 146.8 minimum 40.0 50.0 40.0 83.0 71.0 71.0 maximum 376.0 354.0 271.0 376.0 225.0 195.0 ibe, isometric back extension; lf, lateral flexion; af, abdominal flexion; n, newton; s, seconds. original research sajsm vol. 33 no. 1 2021 4 ancova the four characteristics of athletic performance (40 m sprint, t-test, vj and mbct) were analysed using analysis of covariance (ancova). in each case, the ancova model fitted the characteristics of core stability ibe (strength), lf (strength), af (strength), ibe (endurance), lf (endurance), af (endurance) and core nmc as covariates. in addition, the ’type of sport’ was included since this factor potentially affects athletic performance as measured in the current study. initially, the full ancova model was fitted with all independent variables listed above. furthermore, backward model selection was performed as follows: starting with the full model fitting all the above variables, while at each selection step that variable was chosen for exclusion from the model whose exclusion from the model achieved the largest increase in the schwarz bayesian information criterion (sbc). for each assessment of athletic performance, the results of the final model selected by the sbc are reported here, together with estimates of the regression slopes and associated p-values. results eighty-three female student athletes from the ufs participated in this study. the athletes represented hockey (n=24), netball (n=16), running (n=11), soccer (n=15) and tennis (n=17). table 1 presents the descriptive statistics for the characteristics of core strength and core endurance (overall and by the type of sport). similarly, table 2 summarises the descriptive statistics with respect to core motor control (overall and by the type of sport). correlations tables 3 and 4 present the pearson correlation coefficients table 2. descriptive statistics for core motor/neuromuscular control (nmc) grading: overall and by type of sport team statistic nmc grading total 1 2 3 4 5 all sports frequency 13 17 31 21 1 83 percent 16 21 37 25 1 hockey frequency 3 3 10 8 0 24 percent 13 13 42 33 0 netball frequency 9 5 1 1 0 16 percent 56 31 6 6.3 0 runner frequency 0 2 6 6 1 15 percent 0 13 40 40 7 soccer frequency 1 6 7 3 0 17 percent 6 35 41 18 0 tennis frequency 0 1 7 3 0 11 percent 0 9 64 27 0 table 3. pearson correlation between core strength, core endurance and core motor control tests with athletic performance tests: all sports (n=83) characteristic of core stability statistic athletic performance tests sprint t-test vj mbct ibe (strength) correlation -0.13 -0.44 0.38 0.36 p-value 0.26 0.00* 0.00* 0.00* 95% ci -0.33 to 0.09 -0.60 to -0.25 0.17 to 0.55 0.15 to 0.53 ibe (endurance) correlation -0.16 0.10 -0.14 -0.09 p-value 0.16 0.37 0.21 0.42 95% ci -0.36 to 0.06 -0.12 to 0.31 -0.34 to 0.08 -0.30 to 0.13 lf (strength) correlation -0.10 -0.39 0.90 0.51 p-value 0.35 0.00* 0.00* 0.00* 95% ci -0.31 to 0.12 -0.55 to -0.18 0.19 to 0.56 0.33 to 0.65 lf (endurance) correlation -0.28 -0.06 0.05 0.09 p-value 0.01* 0.59 0.65 0.43 95% ci -0.47 to -0.07 -0.27 to 0.16 -0.17 to 0.26 -0.13 to 0.30 af (strength) correlation -0.05 -0.44 0.44 0.48 p-value 0.62 0.00* 0.00* 0.00* 95% ci -0.27 to 0.16 -0.60 to -0.25 0.24 to 0.60 0.30 to 0.63 af (endurance) correlation -0.35 -0.18 0.34 0.27 p-value 0.00* 0.10 0.00* 0.01* 95% ci -0.52 to -0.14 -0.38 to 0.04 0.13 to 0.51 0.06 to 0.46 nmc correlation -0.32 -0.12 -0.05 -0.05 p-value 0.00* 0.27 0.68 0.65 95% ci -0.50 to -0.11 -0.33 to 0.10 -0.26 to 0.17 -0.26 to 0.17 * indicates statistically significant (p<0.05). bold values indicates moderate, moderately strong and strong correlations. vj, vertical jump; mbct, medicine ball chest throw; ibe, isometric back extension; lf, lateral flexion; af, abdominal flexion; nmc, neuromuscular control. original research 5 sajsm vol. 33 no. 1 2021 correlations table 4. pearson correlation between core strength, core endurance and core motor/neuromuscular control tests with athletic performance tests dependent variable statistic sprint t-test vj mbct hockey (n=24) ibe (strength) correlation 0.05 -0.38 0.33 0.54 p-value 0.83 0.07 0.12 0.01* 95% ci -0.36 to 0.44 -0.68 to 0.03 -0.09 to 0.64 0.16 to 0.77 ibe (endurance) correlation -0.26 -0.19 0.15 0.05 p-value 0.22 0.37 0.49 0.83 95% ci -0.60 to 0.16 -0.55 to 0.23 -0.27 to 0.52 -0.36 to 0.44 lf (strength) correlation -0.12 -0.50 0.37 0.61 p-value 0.58 0.01* 0.07 0.01* 95% ci -0.50 to 0.30 -0.74 to -0.10 -0.04 to 0.67 0.26 to 0.81 lf (endurance) correlation -0.29 -0.34 -0.00 -0.00 p-value 0.17 0.10 0.99 0.99 95% ci -0.62 to 0.13 -0.65 to 0.08 -0.41 to 0.40 -0.41 to 0.40 af (strength) correlation 0.12 -0.41 0.31 0.61 p-value 0.55 0.05* 0.14 0.00* 95% ci -0.29 to 0.50 -0.69 to 0.01 -0.12 to 0.63 0.26 to 0.81 af (endurance) correlation -0.25 -0.21 0.15 0.18 p-value 0.24 0.32 0.48 0.40 95% ci -0.59 to 0.18 -0.56 to 0.21 -0.27 to 0.52 -0.25 to 0.54 nmc correlation -0.24 -0.11 0.04 -0.14 p-value 0.27 0.61 0.85 0.50 95% ci -0.58 to 0.19 -0.49 to 0.31 -0.37 to 0.44 -0.52 to 0.28 netball (n=16) ibe (strength) correlation 0.16 -0.13 -0.48 -0.42 p-value 0.55 0.64 0.06 0.10 95% ci -0.37 to 0.60 -0.58 to 0.40 -0.78 to 0.04 -0.75 to 0.11 ibe (endurance) correlation 0.30 0.17 -0.18 -0.01 p-value 0.26 0.53 0.52 0.97 95% ci -0.24 to 0.69 -0.36 to 0.61 -0.61 to 0.36 -0.50 to 0.49 lf (strength) correlation 0.62 0.56 -0.51 -0.30 p-value 0.01* 0.02* 0.05* 0.26 95% ci 0.16 to 0.85 0.07 to 0.82 -0.79 to 0.00 -0.69 to 0.24 lf (endurance) correlation -0.11 -0.11 -0.08 -0.06 p-value 0.68 0.68 0.76 0.81 95% ci -0.57 to 0.41 -0.57 to 0.41 -0.55 to 0.43 -0.54 to 0.45 af (strength) correlation 0.27 0.24 -0.06 -0.09 p-value 0.32 0.37 0.82 0.75 95% ci -0.27 to 0.67 -0.30 to 0.65 -0.54 to 0.45 -0.56 to 0.43 af (endurance) correlation -0.20 -0.38 0.19 0.44 p-value 0.45 0.15 0.48 0.09 95% ci -0.63 to 0.33 -0.73 to 0.16 -0.34 to 0.62 -0.09 to 0.76 nmc correlation -0.06 -0.04 -0.25 -0.30 p-value 0.81 0.88 0.36 0.25 95% ci -0.54 to 0.45 -0.52 to 0.47 -0.66 to 0.29 -0.69 to 0.24 running (n=15) ibe (strength) correlation -0.36 -0.33 0.40 0.13 p-value 0.19 0.23 0.14 0.64 95% ci -0.73 to 0.20 -0.71 to 0.23 -0.15 to 0.75 -0.41 to 0.60 ibe (endurance) correlation 0.33 0.15 -0.23 -0.31 p-value 0.23 0.60 0.42 0.25 95% ci -0.23 to 0.72 -0.40 to 0.61 -0.66 to 0.33 -0.71 to 0.24 lf (strength) correlation -0.41 -0.44 0.56 0.63 p-value 0.12 0.10 0.03* 0.01* 95% ci -0.76 to 0.14 -0.77 to 0.11 0.04 to 0.83 0.15 to 0.86 lf (endurance) correlation 0.21 0.49 0.11 0.00 p-value 0.46 0.07 0.07 0.99 95% ci -0.35 to 0.65 -0.05 to 0.79 -0.43 to 0.59 -0.51 to 0.51 original research sajsm vol. 33 no. 1 2021 6 tables 3 and 4he pearson correlat table 4 continued. pearson correlation between core strength, core endurance and core motor/neuromuscular control tests with athletic performance tests dependent variable statistic sprint t-test vj mbct running (n=15) af (strength) correlation -0.37 -0.55 0.61 0.52 p-value 0.17 0.03* 0.02* 0.05* 95% ci -0.74 to 0.19 -0.82 to -0.04 0.12 to 0.85 -0.01 to 0.81 af (endurance) correlation -0.03 -0.02 0.71 0.34 p-value 0.27 0.95 0.00* 0.22 95% ci -0.70 to 0.26 -0.52 to 0.50 0.29 to 0.89 -0.22 to 0.72 nmc correlation 0.37 -0.14 -0.27 -0.04 p-value 0.17 0.63 0.33 0.88 95% ci -0.18 to 0.74 -0.60 to 0.41 -0.68 to 0.29 -0.54 to 0.48 soccer (n=17) ibe (strength) correlation -0.30 -0.52 0.63 0.55 p-value 0.25 0.03* 0.01* 0.02* 95% ci -0.68 to 0.22 -0.79 to -0.03 0.20 to 0.85 0.07 to 0.81 ibe (endurance) correlation 0.12 0.04 -0.15 0.16 p-value 0.65 0.89 0.57 0.53 95% ci -0.39 to 0.56 -0.45 to 0.51 -0.58 to 0.36 -0.35 to 0.59 lf (strength) correlation -0.30 -0.05 0.53 0.63 p-value 0.24 0.04* 0.03* 0.00* 95% ci -0.68 to 0.22 -0.78 to -0.01 0.04 to 0.80 0.19 to 0.85 lf (endurance) correlation -0.07 -0.06 -0.08 0.27 p-value 0.78 0.83 0.75 0.29 95% ci -0.53 to 0.42 -0.52 to 0.44 -0.54 to 0.42 -0.25 to 0.66 af (strength) correlation -0.34 -0.56 0.58 0.46 p-value 0.17 0.02* 0.01* 0.06 95% ci -0.70 to 0.17 -0.81 to -0.09 0.12 to 0.83 -0.04 to 0.76 af (endurance) correlation -0.09 -0.26 0.41 0.15 p-value 0.74 0.31 0.10 0.56 95% ci -0.54 to 0.41 -0.66 to 0.26 -0.10 to 0.74 -0.36 to 0.58 nmc correlation -0.55 -0.56 0.44 0.36 p-value 0.02* 0.02* 0.08 0.15 95% ci -0.81 to -0.08 -0.81 to -0.09 -0.07 to 0.75 -0.16 to 0.71 tennis (n=11) ibe (strength) correlation -0.74 -0.59 0.25 0.58 p-value 0.01* 0.05 0.45 0.06 95% ci -0.92 to -0.21 -0.87 to 0.04 -0.42 to 0.73 -0.05 to 0.87 ibe (endurance) correlation -0.67 -0.31 0.28 0.48 p-value 0.03* 0.34 0.40 0.13 95% ci -0.90 to -0.08 -0.76 to 0.37 -0.40 to 0.75 -0.19 to 0.83 lf (strength) correlation -0.56 -0.15 0.20 0.52 p-value 0.07 0.66 0.55 0.10 95% ci -0.86 to 0.08 -0.78 to 0.50 -0.46 to 0.71 -0.14 to 0.85 lf (endurance) correlation -0.43 -0.35 0.22 0.58 p-value 0.19 0.30 0.52 0.06 95% ci -0.81 to 0.25 -0.78 to 0.33 -0.45 to 0.72 -0.05 to 0.87 af (strength) correlation -0.55 -0.43 -0.19 0.40 p-value 0.08 0.19 0.58 0.22 95% ci -0.86 to 0.10 -0.81 to 0.25 -0.70 to 0.47 -0.28 to 0.80 af (endurance) correlation -0.32 0.02 0.25 0.24 p-value 0.34 0.95 0.46 0.48 95% ci -0.76 to 0.36 -0.59 to 0.61 -0.42 to 0.73 -0.43 to 0.73 nmc correlation -0.35 -0.09 0.49 0.23 p-value 0.29 0.80 0.13 0.49 95% ci -0.78 to 0.33 -0.65 to 0.54 -0.18 to 0.83 -0.44 to 0.73 * indicates statistically significant (p<0.05). bold values indicates moderate, moderately strong and strong correlations. vj, vertical jump; mbct, medicine ball chest throw; ibe, isometric back extension; lf, lateral flexion; af, abdominal flexion; nmc, neuromuscular control; ci, confidence interval original research 7 sajsm vol. 33 no. 1 2021 and associated p-values between the characteristics of core strength, core endurance and core nmc, with the four characteristics of athletic performance (overall and by the type of sport). overall for all sports, moderate, statistically significant correlations between ibe (strength) and the t-test, between lf strength) and the mbct, and between af (strength) and the t-test, vj and mbct were observed (table 3). a very strong statistically significant correlation was found between lf (strength) and vj. because of the relatively large sample size overall, even some of the weak correlations in the range 0.27– 0.39 were statistically significant. for hockey, moderate statistically significant correlations were found between ibe (strength), lf (strength), and af (strength) and the mbct, and between lf (strength) and af (strength) and the t-test (table 4). for netball, moderate statistically significant correlations were observed between lf (strength) and the sprint, t-test, and vj, and between af (endurance) and the mbct (table 4). for runners, moderate statistically significant correlations were found between ibe (strength) and the vj, between lf (strength) and the sprint, t-test, vj and mbct, between af (strength) and the t-test, vj and mbct, between lf (endurance) and the t-test, and a strong statistically significant correlation between af (endurance) and vj (table 4). for soccer, there were moderately strong statistically significant correlations between ibe (strength) and the t-test, vj and mbct, between lf (strength) and vj and mbct, between af (strength) and the t-test, vj and mbct, between af (endurance) and the vj, and between core nmc and the sprint, t-test and vj (table 4). because of the relatively large sample size overall, even some negligible correlations in the range 0.00–0.10 were statistically significant. for tennis, moderate statistically significant correlations were found between ibe (strength) and the t-test and mbct, between lf (strength) and the sprint and mbct, between af (strength) and the sprint, t-test and mbct, between ibe (endurance) and the sprint and mbct, between lf (endurance) and the sprint and mbct, and between core nmc and vj (table 4). a strong statistically significant correlation was found between ibe (strength) and the sprint. table 5 presents the results of the ancova values followed by the model selection. the only selected predictor of the sprint was lf (strength). higher lf (strength) led to lower sprint times (negative association). for the t-test, the selected predictors were ibe (endurance) (positive association), ibe (strength) and af (strength) (negative association). for vj, the selected predictors were af (strength) and af (endurance) (positive association). furthermore, significant differences between sports with regard to vj were observed (the p-values in table 5 refer to the differences between tennis and the other sport codes). finally, the only selected predictor for the mbct was af (strength) (positive association). discussion a well-trained athlete is expected to have general skills such as speed, agility and explosive power, in addition to sport-specific attributes. the current study's findings were similar to the results of sharrock et al.,[5] who reported a weak relationship between core stability (as measured by the double leg lowering test) and athletic performance. our findings are also in agreement with nesser et al.,[22] who reported a moderate correlation between core stability and sport-specific assessments. we found that hockey players demonstrated the highest ibe, lf and af characteristics of core strength, and tennis players the lowest. this could be attributed to the fact that the body position of a hockey player is always flexed at the lumbar spine, with combined rotational movements that require good core strength during various hitting and pushing techniques.[23] zingaro[24] proposed that the core and upper extremity muscles are responsible for 54% of force production when delivering in a tennis serve. moreover, it has been found that the speed of shoulder movement when serving can be up to 76 kilometres an hour, which could imply that most of a serve's explosive power in tennis players originates from the shoulder and not the core. despite inconsistent findings, researchers are of the opinion that different sporting codes require different functions of core strength. runners had the highest ibe, lf and af characteristics of core endurance, and netball players the lowest. tong et al.[25] noted that core muscle fatigue may limit running endurance. clark et al.[26] reported that improved core endurance reduced overall running times in high school cross-country runners. we concur with previous literature[25,26] that runners require core table 5. ancova with model selection: relationship between athletic performance and core endurance, core strength and core neuromuscular control dependent variable independent variable estimate standard error p-value sprint intercept 4.439 0.282 lf (strength) -0.0009 0.0002 0.00* t-test intercept 4.740 2.432 ibe (strength) -0.0008 0.0003 0.03* af (strength) -0.003 0.0005 0.00* ibe (endurance) 0.003 0.001 0.02* vj intercept 39.135 3.900 hockey -3.395 1.490 0.03* netball 1.7548 1.427 0.22 runner 4.164 1.267 0.00* soccer 3.217 1.128 0.01* af (strength) 0.009 0.003 0.00* af (endurance) 0.017 0.007 0.01* mbct intercept -1.266 1.286 af (strength) 0.001 0.0003 0.00* * indicates statistically significant (p<0.05). ancova, analysis of covariance; vj, vertical jump; mbct, medicine ball chest throw; lf, lateral flexion; ibe, isometric back extension; af, abdominal flexion. original research sajsm vol. 33 no. 1 2021 8 endurance for improved athletic performance, as a positive correlation was found between characteristics for core endurance and the sprint and t-test. optimal performance in netball depends on the interaction between several fundamental factors relating to the balance, agility and explosive power of players.[27] hence, muscle endurance is not the most relevant component in training interventions for netball players. in addition, netball players depend more on the eccentric strength of the quadriceps when cutting and landing, rather than the core musculature,[28] which could explain why the netball players in this study showed the lowest mean values for core endurance. this is supported by the fact that in this study netball players had lower core nmc (grade 1) than tennis players (grade 3) and runners (grade 4). similar to our findings, venter et al.[28] reported that netball players rely more on lower extremity strength for cutting and landing movements than the core musculature. diverse views on the significance of core stability in sporting performance still exist. no studies reviewed for this research used our battery of tests to assess the different components of core stability (strength, endurance and neuromuscular control), as well as its relationship to different sports (hockey, netball, runners, soccer and tennis). therefore, no meaningful comparisons with other studies reported in the literature could be made in this regard. potential limitations of this study are that only five sporting codes were examined. these sporting codes' specific techniques and skills might not be representative of all sports. only female athletes of the ufs participated, while male athletes may yield different results from female athletes. athletes were assessed during different times in the conditioning season, and differences in conditioning training programmes might have influenced the results. the lack of gold standard tests to assess the strength, endurance and neuromuscular components of core stability could also be a limitation. sport-specific assessments should be considered to assess core stability. the athletic performance tests did not account for the specific demands of the different sporting codes. core stability and athletic performance are complex concepts, with multiple factors playing a role in both. future research on core stability and athletic performance, with specific attention to the demands of different sporting codes, would benefit both the sport and rehabilitation sectors. conclusion this study found correlations between core stability and athletic performance, even though many correlations were only weak or moderately weak. different sporting codes seem to require different components of core stability. when these sporting codes are considered separately, there were moderately strong correlations between core stability and its sub-groups and athletic performance tests. therefore, core stability can be considered an important modality when trying to improve athletic performance, but should not be the primary focus of exercise training programmes. the findings of this study can equip athletes, coaches, conditioning staff and rehabilitation specialists to better design exercise training programmes by implementing sport-specific modalities into programmes that duplicate the demands of the respective sporting codes. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: dr daleen struwig, medical writer/ editor, ufs, for technical and editorial preparation of the manuscript. author contributions: mdb contributed to the planning and execution of the study, collected the data and wrote the draft article. dc initiated the study, contributed to its planning and collaborated on writing the article. rs contributed to the planning of the study, performed the statistical analysis of the data and collaborated on the writing of the article. all the authors approved the final version of the article. references 1. hibbs ae, thompson kg, french d, et al. 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[doi: 10.1519/jsc.0b013e3181874564] [pmid: 18978631] 23. clarke li. a comparison study between core stability and trunk extensor endurance training in the management of acute low back pain in field hockey players. unpublished master's dissertation. durban: durban university of technology; 2009. https://openscholar.dut.ac.za/bitstream/10321/412/4/clarke_2009 .pdf (accessed 2 march 2021). 24. zingaro re. a correlation between core strength and serve velocity in collegiate tennis players. unpublished msc thesis. california, pa: california university of pennsylvania; 2008. http://libweb.calu.edu/thesis/umi-cup-1060.pdf (accessed 2 march 2021). 25. tong tk, wu s, nie j, et al. the occurrence of core muscle fatigue during high-intensity running exercises and its limitation to performance: the role of respiratory work. j sports sci med 2014;13(2):244–251. [pmid: 24790475] 26. clark aw, goedeke mk, cunningham sr, et al. effects of pelvic and core strength training on high school cross-country race times. j strength cond res 2017;31(8):2289–2295. [doi: 10.1519/jsc.0000000000001729] [pmid: 27893484] 27. ferreira ma, spamer ej. biomechanical, anthropometrical and physical profile of elite university netball players and the relationship to musculoskeletal injuries. s afr j res sport phys educ recreat 2010;32(1):57–67. [doi: 10.4314/sajrs.v32i1.54100] (accessed 6 april 2021). 28. venter re, masterson c, tidbury gb, et al. relationship between functional movement screening and performance tests in elite university female netball players. s afr j res sport phys educ recreat 2017;39(1):189–198. https://www.ajol.info/index.php/sajrs/article/view/154072 (accessed 6 april 2021). doi:%2010.1016/j.ptsp.2005.02.006 doi:%2010.1007/s00586-009-1020-y doi:%2010.23937/2469-5718/1510074 doi:%2010.1371/journal.pone.0187237 doi:%2010.1123/ijspp.2013-0121 https://www.academia.edu/29929452/validity_of_alternative_field_system_for_measuring_vertical_jump%20height https://www.academia.edu/29929452/validity_of_alternative_field_system_for_measuring_vertical_jump%20height doi:%2010.1123/jab.2016-0239 doi:%2010.1123/jab.2016-0239 doi:%2010.1213/ane.0000000000002864 doi:%2010.1519/jsc.0b013e3181874564 doi:%2010.1519/jsc.0b013e3181874564 https://openscholar.dut.ac.za/bitstream/10321/412/4/clarke_2009.pdf https://openscholar.dut.ac.za/bitstream/10321/412/4/clarke_2009.pdf http://libweb.calu.edu/thesis/umi-cup-1060.pdf doi:%2010.1519/jsc.0000000000001729 doi:%2010.1519/jsc.0000000000001729 108 sajsm vol 18 no. 4 2006 classical overtraining syndrome the olympic motto citius, altius, fortius (faster, higher, stronger) epitomises the goal of athletic training. as athletes strive to improve their performance, inevitably their training load increases. frequently their training strategies are successful and their performance improves. however, substantial anecdotal as well as experimental evidence 17,18 links intensified training, for an extended period, with a chronic decrement in athletic performance. this reduced performance may manifest as an athlete failing to improve/maintain his/her previous performances, despite undergoing more intensive training, or an athlete reporting an inability to regain previous form following a vigorous competition. athletes must undergo significant amounts of physiological as well as psychological stress during training in order to provide sufficiently potent stimuli for appropriate adaptations to occur. to ensure that the athlete adapts favourably to the training load imposed, adequate rest is a crucial part of any training programme. if rest is not sufficient and the exercise stress alone or combined with other stressors (health, nutritional, environmental or psychological) is too great, the athlete may fail to adapt (maladapt) and enter a state of ‘overreaching’. if the athlete continues training with insufficient rest, and in addition is exposed to further stressors (mentioned above), then a state of chronic underperformance may occur. this condition has been referred to as overtraining syndrome (ots), but has also been referred to as staleness or burnout syndrome. 22 it should be noted that although the condition of ‘overreaching’ may be a precursor to overtraining, certain coaches and athletes regard this condition as an integral part of training to achieve a supercompensatory effect. 22 however, if an athlete is overreached, approximately 2 weeks of rest should result in a return to previous performance levels or even improved performance. 22 in contrast, the ots athlete will not recover in 2 weeks. it may take months for this athlete to recover, and in some instances the individual may never recover. 22 ots is commonly reported to occur in around 10 20% of elite endurance athletes 32 and affects up to 65% of longdistance runners at some point in their athletic career. 28 this condition should therefore not be regarded as a marginal problem but as an important and frequent event in the athletic community. 22 redefinition of overtraining syndrome although the aetiology of ots remains elusive the term ‘overtraining syndrome’ may be a misnomer, since it implies that exercise is the sole causative factor of the syndrome. the recent redefinition of the syndrome focuses not only on the outcome, but also implies that the cause may be multireview article causes of extreme fatigue in underperforming athletes – a synthesis of recent hypotheses and reviews p j robson-ansley (phd)1 l lakier smith (phd)2 1 institute of biomedical and biological sciences, department of sport and exercise sciences, university of portsmouth, uk 2 tshwane university of technology, pretoria abstract the underperformance syndrome (ups), previously known as the overtraining syndrome (ots), has been defined as a persistent decrement in athletic performance capacity despite 2 weeks of relative rest. clinical research has suggested that cytokines play a key role in fatigue in disease and chronic fatigue syndrome. furthermore, it has recently been demonstrated that exogenous administration of interleukin-6 (il-6) increases the sensation of fatigue during exercise. in light of current cytokine and chronic fatigue syndrome research, this article reviews and updates the cytokine theories that attempt to explain the aetiology of the debilitating fatigue experienced in ots/ups. initially, it was proposed that ups may be caused by excessive cytokine release during and following exercise, causing a chronic inflammatory state and ‘cytokine sickness’. more recently, the hypothesis was extended and it was proposed that time-dependent sensitisation could provide a model through which the aetiology of ups may be explained. according to this model, the principal abnormal factor in ups is an intolerance/heightened sensitivity to il-6 during exercise. correspondence: p j robson-ansley institute of biomedical and biological sciences department of sport and exercise sciences university of portsmouth portsmouth po1 2er united kingdom tel: +44 2392848484 fax: +44 2392842641 e-mail: paula.ansley@port.ac.uk 110 sajsm vol 18 no. 4 2006 factorial 39 being triggered by an accumulation of either sport and/or non-sport-related stress. 29,43 factors associated with the development of ots may include extremely high loads of training with insufficient rest 18 and/or excessive psychological stress 29 and/or illness. 29 in order to reflect the multidimensional nature of ots, it is proposed that the broader term ‘underperformance syndrome’ (ups) be adopted instead of ots. 7 similar to the previous definition, ups is defined as a persistent decrement in athletic performance, despite 2 weeks of relative rest, confirmed by both coach and athlete. 7 the primary difference in the terminology is that ups focuses on the final outcome of the condition, namely underperformance, whereas ots focused on a single causative factor, namely the training load. ups is the acronym that will be used in this article. behavioural and mood-related signs and symptoms of ups fatigue appears to be the most prominent and debilitating symptom of ups. 12 specific fatigue-related symptoms reported by ups athletes include feeling continuously tired despite adequate rest, as well as waking tired and unrefreshed despite an adequate duration of undisturbed sleep. 12 in addition to these generalised reports of fatigue, the athlete complains extensively of local fatigue usually in the exercising muscles, and frequently describes the feeling of ‘heavy legs’ during exercise. 12 apart from the common symptom of persistent fatigue, a plethora of fatigue-related signs and symptoms have been associated with ups, as is comprehensively detailed by fry et al. 14 predominant symptoms include: (i) general malaise/flu-like symptoms; (ii) reduced interest in training and competing; (iii) reduced concentration; (iv) reduced socialising; (v) increased daytime sleepiness and waking unrefreshed; (vi) reduced appetite; and (vii) depression. many of the above symptoms may in fact be related to an underlying depression since many of these features, including fatigue, reflect classic neurovegetative features of depression. 1 however, the issue of whether or not the ups athlete is suffering from depression per se, remains somewhat controversial. morgan and colleagues 31 have suggested that many ups athletes suffer from what appears to be clinical depression and that frequently depression is the first sign of ups, but is often ignored if the athlete is still performing adequately. in support of the presence of depression, armstrong and vanheest 2 have suggested that this could well be the underlying cause of ots and recommend the use of antidepressants to treat ups. uusitalo et al. 46 also support the notion of depression being associated with ups. it has also been postulated 6,12 that clinical depression is not a commonly reported sign of ups. these researchers have postulated that when depression is present, rather than being a cause of ups, it may occur at a later stage as a consequence of ups, due to the frustration the athlete experiences as a consequence of underperformance. thus many questions exist concerning the association between ups and depression. questions include whether or not depression actually occurs, and if it does, what is the time point of onset of depression (does this precede the reduction in performance or is it a consequence); and what is the degree of depression (mild/moderate/severe). an additional issue is whether or not depression is a separate symptom or part of a more extensive syndrome, ‘sickness behaviour’, 41 which will be discussed in the next section. 19,37 lastly, important from the perspective of this article is that if depression does exist, is the fatigue experienced during ups part of the depressed symptomology or is the fatigue a symptom in and of itself. communication of the sensation of fatigue from body to brain the cytokine hypothesis of overtraining syndrome the universal and most debilitating symptom in ups is the persistent fatigue reported by athletes. a hypothesis that attempts to explain some of these fatigue-associated mood/ behaviour changes is the ‘cytokine hypothesis of overtraining’. 43 this proposes that intense and frequent training/competing, over an extended period, with insufficient rest/recovery time, may result in exercise-induced tissue trauma. it was further suggested that this diffuse tissue trauma may evoke a chronic, systemic inflammatory response. 13 chronic inflammation is a complex event and, amongst other sequelae, there is increased synthesis of pleiotropic proteins, viz. cytokines, produced by many eukaryotic cells. cytokines may be grouped into several different families based on structure and/or function, such as antiand pro-inflammatory cytokines. the pro-inflammatory cytokines, which appear to be associated with chronic inflammation, include interleukin (il)-1β, il-6 and/or tumour necrosis factor-α (tnfα).13 it was further hypothesised that elevated circulating levels of any of these circulating cytokines could account for the many previously noted signs and symptoms of ups, since cytokines have been shown to trigger alterations in immune, metabolic, physiological and behavioural responses. 9,10,13 although it was suggested that the primary source of serum cytokines was due to tissue trauma, it was also acknowledged that other factors such as illness, could initiate elevations in peripheral cytokine levels. for a long while researchers have known that ‘information’ from the central nervous system (cns) can be transmitted to the periphery of the body, via the sympathetic nervous system and/or the hypothalamic pituitary axis. 27 however, the manner in which peripheral body-events, such as infection or injury, can ‘inform’ the cns, has only recently been elucidated. it is now clear that cytokines function as messenger molecules that can access the cns from the periphery. this may occur via neural and/or humoral routes. 10 it should be noted that cytokines may also be produced in the cns and subsequently released into the peripheral circulation. 41 this circular, interconnected, reverberating mind-body interaction forms the basis of psychoneuroimmunology. 41 once within the cns, il-1β, il-6 and tnfα are capable of activating specific brain structures, resulting in the sajsm vol 18 no. 4 2006 111 manifestation of a constellation of behaviours referred to as ‘sickness behaviour’ or ‘recuperative behaviour’. 19,37 this cluster of behaviours includes the following signs and symptoms: weakness, malaise, listlessness, and inability to concentrate. 19,37 additionally, individuals are somewhat depressed and lethargic, showing little interest in their surroundings. 19,37 much of this is similar to what has been described in ups. 14 similarly to what hans selye described as a generalised stress response, which occurs in response to a variety of different stressors, 42 this sickness behaviour may be regarded as a generalised response to illness and/or injury, and may also be induced by a variety of pathogens and/or tissue trauma. initially sickness behaviour was regarded as an unimportant, inconvenient by-product of sickness/injury. however, it is now recognised that it represents a highly organised, motivated strategy used to fight infection/illness so as to optimise healing/recovery from trauma. 19,37 in summary, the cytokine hypothesis suggests that any of the pro-inflammatory cytokines (il-1β, and/or il-6 and/ or tnfα) that may be produced by excessive training with insufficient rest and subsequent tissue trauma, may be responsible for many of the psychological changes including the extreme fatigue seen in ups. interleukin-6 fatigue hypothesis of ups although the cytokine hypothesis of ots could account for different aetiologies of ots, such as psychological stress or epstein-barr virus, 43 the emphasis was on excessive training/competing with insufficient rest/recovery and subsequent tissue trauma being the primary initiator. furthermore, the author proposed several pro-inflammatory cytokines being implicated in ups, including il-1β and tnfα. although these 2 cytokines may ultimately be implicated in ups, substantially more research has been done pertaining to exercise and il-6, as well as fatigue and il-6, hence the ‘interleukin-6 hypothesis of ups’. 39 the il-6 hypothesis emphasises that factors aside from exercise-induced tissue trauma, trigger a dysregulated inflammatory response in ups, causing either increased levels of circulating il-6 or an increased sensitivity to il-6. additionally, this hypothesis stresses the central role of il-6 in the persistent fatigue experienced during ups. apart from fatigue-inducing properties, il-6 has many functions and a wide range of biological activities, such as support of erythropoeisis, regulation of immune system responses, 20 and generation of acute-phase reactions. 20 recent research suggests that il-6 may also play a metabolic role inducing counterregulatory hormones, hepatic glucose output and lipolysis (reviewed elsewhere 35,36 ). furthermore, il-6 has been proposed as a glucose-regulator during prolonged exercise. 45 il-6 induces the sensation of fatigue at rest studies investigating the effect of il-6 on resting healthy individuals showed that low doses of recombinant human il-6 (rhil-6, a synthesised form of il-6) induce an increased sensation of fatigue. 3,44 in one study subjects were given either a single low dose of il-6 that mimicked systemic increases in this cytokine typically observed during a moderate infection (and also comparable with those measured in athletes following prolonged exercise 33 ), or a placebo. 44 a self-reported mood state questionnaire was completed 3 hours after il6 administration; scores showed that subjects were feeling significantly more tired compared with the placebo trial. all signs and symptoms associated with the il-6 administration had resumed pre-trial values when assessed 12 hours later. although clinicians readily acknowledge the fatigue-inducing properties of il-6, 21,23,48 these properties have gone largely unrecognised by exercise physiologists. exogenous il-6 administration exacerbates fatigue in healthy trained runners during exercise recent data obtained from a performance-related study 40 indicate that il-6 may also play a role in the sensation of fatigue during exercise. when a dose of rhil-6 was administered to subjects prior to a 10 km time trial (to induce equivalent plasma concentrations found following prolonged exercise or a moderate infection), subjects reported an increased sensation of physical and psychological fatigue during the exercise trial that ultimately resulted in a significant decrement in performance. this led the researchers to suggest that il-6 may also act as a circulating fatigue-inducing molecule during exercise. both global mood state and fatigue worsened as scores were significantly higher immediately post-exercise in the il-6 trial compared with placebo. the effect of the il-6 treatment was relatively short-lived, as by approximately 3 hours post-il-6 administration, scores for global mood state and fatigue 16 had returned to pre-treatment values. it appears that transiently elevated levels of il-6 negatively affect the sensation of fatigue and global mood state in healthy runners. rating of perceived exertion 5 was also measured throughout the exercise trials but was not different between trials despite the subjects running slower during the il-6 trial (robson-ansley et al. – unpublished data, 2003). this may be perceived as subjects running with the ‘same pain but less gain’ compared with the placebo trial. subjects felt they were running with the same effort but were, in fact, running significantly slower; some subjects reported that they could not get their legs moving and complained of ‘heavy legs’ during the exercise trial. this is the first study to directly identify that an elevated plasma il-6 concentration (similar to that measured following a prolonged bout of exercise) has fatigue-inducing properties that can affect both mood state and athletic performance, both of which are factors associated with ups. heightened sensitivity to il-6 in chronic fatigue syndrome – the missing link in ups? ups has several parallels with chronic fatigue syndrome (cfs), in particular persistent fatigue and mood disturbances, 12 hence research findings on cfs may aid elucidation of the aetiology of ups. resting plasma il-6 levels appear similar between healthy athletes and ups athletes, 34 as well as between healthy individuals and cfs patients. whether 112 sajsm vol 18 no. 4 2006 or not the il-6 response to exercise differs between healthy and ups athletes is currently undetermined. although resting levels of il-6 in healthy and chronically fatigued individuals may be comparable, recent research highlights the fact that cfs patients have a heightened sensitivity to il-6 compared with normal, healthy individuals. 3,15 following il-6 administration, cfs patients experienced a greater number of somatic symptoms such as aches, fatigue and malaise, with a shorter latency, compared with the healthy controls. 3 the feelings of fatigue and malaise remained up to 24 hours after the rhil-6 administration in the cfs group. unfortunately, initial levels of il-6 were not reported for the patients with cfs or normal control subjects, so it is not known whether cfs patients commenced the study with elevated plasma il6 levels. the cause of the abnormal/heightened response to rhil-6 in cfs is unclear, but elucidation of this may provide insight into the chronic fatigue during exertion experienced by athletes with ups. heightened sensitivity to il-6 in ups the il-6 hypothesis 39 proposes that time-dependent sensitisation (tds) to il-6, similar to what has been proposed for cfs patients, could provide a model through which the aetiology of ups may be explained. tds is described as a progressive and persistent amplification of behavioural and biochemical responses to repeated intermittent stimuli over time. 4 the model proposes that a long-term or permanent physiological adaptation occurs as a consequence of initial exposure to a severe physical or psychological stimulus (or stimuli). this results in the individual developing a progressive and amplified intolerance on repeated exposure rather than developing a tolerance. in accordance with the tds model, the il-6 hypothesis proposes that initial stressors or trigger factors for ups such as severe infection,such as severe infection, 47 excessive exercise, heat stroke 8 or severe psychological stress 25,26 evoke a substantial cytokine response. these proposed trigger factors may sensitise individuals in such a manner that they become sensitive to il-6 and exercise-intolerant (maladapting to the exercise stress), causing performance decrements with each subsequent training session (fig. 1). the exact physiological mechanism affected by the initial exposure to a severe stressor is unknown, but it is thought that stressors and/or the biochemical responses to the stressors could induce gene transcription factors. 38 activation of these gene transcription factors by exposure to a significant stressor could cause a long-term alteration of responsivity to future stressors, possibly by increasing cytokine receptor densities or soluble receptor concentrations. in support of this, one study 30 demonstrated that repeated exposure to stress induces changes in il-6 mrna and il-6 receptor mrna in the brain, which are different from those induced during a single exposure to stress. alternatively, the initial trigger factor(s) that stimulated the tds may have caused permanent or long-term damage to the blood-brain barrier (bbb). the integrity of the bbb permeability to cytokines can be altered by exposure to factors such as excessive cytokine exposure, 11 heat stress 49 and endotoxins. 24 it is conceivable that this increased permeability to cytokines may induce a heightened degree of ‘sickness behaviour’ and associated fatigue, upon a subsequent exposure that could be evoked by factors such as prolonged exercise. the il-6 hypothesis of ups suggests that the relentless fatigue experienced by these athletes is due to stimulation of certain cns structures by an increase in or heightened sensitivity to il-6. present research suggests that resting blood levels of il-6 in ups athletes are similar to levels in healthy controls; there is minimal evidence on post-exercise levels of il-6 in ups athletes. the possibility of increased sensitivity to il-6 was proposed as a possible explanation for the extreme fatigue experienced by these athletes. summary and conclusion two hypotheses were presented in this article in an attempt to explain the debilitating fatigue experienced during ups. the cytokine hypothesis 43 stresses excessive training with resultant tissue damage and the potential role of several cytokines that could induce fatigue, and that are possibly associated with depression. the il-6 hypothesis 39 focuses on a possible central role for this one cytokine, stressing multi-factorial causes of elevated il-6 in ups. this hypothesis further suggests that an increased sensitivity to il-6 could be implicated in the extreme fatigue associated with ups. however, to date there is limited information to support these hypotheses. thus it is acknowledged that extensive animal and human studies are warranted to either support or refute these suppositions. references 1. anisman h, merali z. cytokines, stress, and depressive illness. brain behav immun 2002; 16: 513-24. fig. 1. interleukin-6 fatigue hypothesis of underperformance syndrome. a schematic diagram of the time-dependent sensitisation phenomenon (adapted with permission from robson 39 . i = initial exposure to stressor induces long-term change in blood-brain barrier integrity and/or c-fos expression; ii, iii, iv = further exposure to stressor/s triggers an intolerance/heightened sensitivity to il-6 causing further performance deterioration). time intolerance/heightened sensitivity to il-6 response normal adaptation to training p e rf o rm a n c e s e n s it iv it y to il -6 initial exposure to stressor re-exposure to stressor/s failure to adapt to training timei ii iii iv re-exposure to stressor/s re-exposure to stressor/s 114 sajsm vol 18 no. 4 2006 2. armstrong le, vanheest jl. the unknown mechanism of the overtrain armstrong le, vanheest jl. the unknown mechanism of the overtrain-armstrong le, vanheest jl. the unknown mechanism of the overtraining syndrome: clues from depression and psychoneuroimmunology. sports med 2002; 32: 185-209. 3. arnold mc, papanicolaou da, o’�rady ja, arnold mc, papanicolaou da, o’�rady ja,arnold mc, papanicolaou da, o’�rady ja, et al. using an interleukin-6 challenge to evaluate neuropsychological performance in chronic fatigue syndrome. psychol med 2002; 32: 1075-89. 4. bell ir. white paper: neuropsychiatric aspects of sensitivity to low-level bell ir. white paper: neuropsychiatric aspects of sensitivity to low-levelbell ir. white paper: neuropsychiatric aspects of sensitivity to low-level chemicals: a neural sensitization 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kafri �, kobiler d, ben nathan d. viral neuroinvasion and encephalitis induced by lipopolysaccharide and its mediators. j exp med 1992; 176: 707-12. 25. maes m, lin ah, delmeire l, maes m, lin ah, delmeire l,maes m, lin ah, delmeire l, et al. elevated serum interleukin-6 (il-6) and il-6 receptor concentrations in posttraumatic stress disorder following accidental man-made traumatic events. biol psychiatry 1999; 45: 833-9. 26. �aes �, ombelet �, �e �ongh r, �enis �, �osmans �. the inflammatory �aes �, ombelet �, �e �ongh r, �enis �, �osmans �. the inflammatory�aes �, ombelet �, �e �ongh r, �enis �, �osmans �. the inflammatory response following delivery is amplified in women who previously suffered from major depression, suggesting that major depression is accompanied by a sensitization of the inflammatory response system. j affect disord 2001; 63: 85-92. 27. maier sf, watkins lr. cytokines for psychologists: implications of bidirecmaier sf, watkins lr. cytokines for psychologists: implications of bidirec-maier sf, watkins lr. cytokines for psychologists: implications of bidirectional immune-to-brain communication for understanding behavior, mood, and cognition. psychol rev 1998; 105: 83-107. 28. mckenzie dc. markers of excessive exercise. mckenzie dc. markers of excessive exercise.mckenzie dc. markers of excessive exercise. can j appl physiol 1999; 24: 66-73. 29. meehan hl, bull sj, wood dm, james dv. the overtraining syndrome: a meehan hl, bull sj, wood dm, james dv. the overtraining syndrome: ameehan hl, bull sj, wood dm, james dv. the overtraining syndrome: a multicontextual assessment. the sport psychol 2004; 18: 154-71. 30. miyahara s, komori t, fujiwara r, miyahara s, komori t, fujiwara r,miyahara s, komori t, fujiwara r, et al. effects of repeated stress on expression of interleukin-6 (il-6) and il6 receptor mrnas in rat hypothalamus and midbrain. life sci 2000; 66: l93-8. 31. morgan wp, brown dr, raglin js, o’connor pj, ellickson ka. psychomorgan wp, brown dr, raglin js, o’connor pj, ellickson ka. psycho-morgan wp, brown dr, raglin js, o’connor pj, ellickson ka. psychological monitoring of overtraining and staleness. br j sports med 1987; 21: 107-14. 32. morgan wp, costill dl, flynn m�, raglin js, o’connor pj. mood dismorgan wp, costill dl, flynn m�, raglin js, o’connor pj. mood dis-morgan wp, costill dl, flynn m�, raglin js, o’connor pj. mood disturbance following increased training in swimmers. med sci sports exerc 1988; 20: 408-14. 33. ostrowski k, rohde t, zacho m, asp s, pedersen bk. evidence that interostrowski k, rohde t, zacho m, asp s, pedersen bk. evidence that inter-ostrowski k, rohde t, zacho m, asp s, pedersen bk. evidence that interleukin-6 is produced in human skeletal muscle during prolonged running. j physiol 1998; 508: pt 3, 949-53. 34. parry-billings m, budgett r, koutedakis �, parry-billings m, budgett r, koutedakis �,parry-billings m, budgett r, koutedakis �, et al. plasma amino acid concentrations in the overtraining syndrome: possible effects on the immune system. med sci sports exerc 1992; 24: 1353-8. 35. pedersen bk, steensberg a, fischer c, keller c, ostrowski k, schjerling p. pedersen bk, steensberg a, fischer c, keller c, ostrowski k, schjerling p.pedersen bk, steensberg a, fischer c, keller c, ostrowski k, schjerling p. exercise and cytokines with particular focus on muscle-derived il-6. exerc immunol rev 2001; 7: 18-31. 36. pedersen bk, steensberg a, schjerling p. exercise and interleukin-6. pedersen bk, steensberg a, schjerling p. exercise and interleukin-6.pedersen bk, steensberg a, schjerling p. exercise and interleukin-6. curr opin hematol 2001; 8: 137-41. 37. pollmacher t, haack m, schuld a, reichenberg a, �irmiya r. low levels of pollmacher t, haack m, schuld a, reichenberg a, �irmiya r. low levels ofpollmacher t, haack m, schuld a, reichenberg a, �irmiya r. low levels of circulating inflammatory cytokines do they affect human brain functions? brain behav immun 2002; 16: 525-32. 38. post rm. transduction of psychosocial stress into the neurobiology of repost rm. transduction of psychosocial stress into the neurobiology of re-post rm. transduction of psychosocial stress into the neurobiology of recurrent affective disorder. am j psychiatry 1992; 149: 999-1010. 39. robson p. elucidating the unexplained underperformance syndrome in robson p. elucidating the unexplained underperformance syndrome inrobson p. elucidating the unexplained underperformance syndrome in endurance athletes: the interleukin-6 hypothesis. sports med 2003; 33: 771-81. 40. robson-ansley pj, de milander l, collins m, noakes td. acute interleukinrobson-ansley pj, de milander l, collins m, noakes td. acute interleukin-robson-ansley pj, de milander l, collins m, noakes td. acute interleukin6 administration impairs athletic performance in healthy, trained male runners. can j appl physiol 2004; 29: 411-8. 41. schiepers oj, wichers mc, maes m. cytokines and major depression. schiepers oj, wichers mc, maes m. cytokines and major depression.schiepers oj, wichers mc, maes m. cytokines and major depression. prog neuropsychopharmacol biol psychiatry 2005; 29: 201-17. 42. selye h, fortier c. adaptive reaction to stress. selye h, fortier c. adaptive reaction to stress.selye h, fortier c. adaptive reaction to stress. psychosom med 1950; 12: 149-57. 43. smith ll. cytokine hypothesis of overtraining: a physiological adaptation to smith ll. cytokine hypothesis of overtraining: a physiological adaptation tosmith ll. cytokine hypothesis of overtraining: a physiological adaptation to excessive stress? med sci sports exerc 2000; 32: 317-31. 44. spath-schwalbe e, hansen k, schmidt f, spath-schwalbe e, hansen k, schmidt f,spath-schwalbe e, hansen k, schmidt f, et al. acute effects of recombinant human interleukin-6 on endocrine and central nervous sleep functions in healthy men. j clin endocrinol metab 1998; 83: 1573-9. 45. steensberg a, van hall �, osada t, sacchetti m, saltin b, klarlund pb. steensberg a, van hall �, osada t, sacchetti m, saltin b, klarlund pb.steensberg a, van hall �, osada t, sacchetti m, saltin b, klarlund pb. production of interleukin-6 in contracting human skeletal muscles can account for the exercise-induced increase in plasma interleukin-6. j physiol 2000; 529: pt 1, 237-42. 46. uusitalo al, valkonen-korhonen m, helenius p, vanninen e, bergstrom uusitalo al, valkonen-korhonen m, helenius p, vanninen e, bergstromuusitalo al, valkonen-korhonen m, helenius p, vanninen e, bergstrom ka, kuikka jt. abnormal serotonin reuptake in an overtrained, insomnic and depressed team athlete. int j sports med 2004; 25: 150-3. 47. �allieres l, rivest s. interleukin-6 is a needed proinflammatory cytokine in �allieres l, rivest s. interleukin-6 is a needed proinflammatory cytokine in�allieres l, rivest s. interleukin-6 is a needed proinflammatory cytokine in the prolonged neural activity and transcriptional activation of corticotropin releasing factor during endotoxemia. endocrinology 1999; 140: 3890-903. 48. vgontzas an, papanicolaou da, bixler eo, kales a, tyson k, chrousos vgontzas an, papanicolaou da, bixler eo, kales a, tyson k, chrousosvgontzas an, papanicolaou da, bixler eo, kales a, tyson k, chrousos �p. elevation of plasma cytokines in disorders of excessive daytime sleepiness: role of sleep disturbance and obesity. j clin endocrinol metab 1997; 82: 1313-6. 49. wijsman ja, shivers rr. heat stress affects blood-brain barrier permewijsman ja, shivers rr. heat stress affects blood-brain barrier perme-wijsman ja, shivers rr. heat stress affects blood-brain barrier permeability to horseradish peroxidase in mice. acta neuropathol (berl) 1993; 86: 49-54. 136 sajsm vol 18 no. 4 2006 introduction following its sweeping rise in popularity in the lay press and extensive scientific publications in the last decade, creatine remains one of the most widely used and recommended nutritional supplements for the purpose of obtaining an ergogenic effect. 1,4,14-18,27,36 it is frequently recommended to power athletes and other individuals wishing to improve performance in high-intensity training or competition, or seeking gains in strength and muscle mass. 1,2,4,5,9,14,21,22,36 creatine is an amino acid derivative which is both synthesised in the body and obtained in the diet, mainly from meat sources. 1,36 most is stored within skeletal muscle fibres, where it is found in its free (cr) and phosphorylated (phosphocreatine (pc)) form. the biological significance of pc lies in its ability to assist in rapidly resynthesising adenosine triphosphate (atp) during high-intensity work via the cytosolic creatine kinase reaction, thereby buffering an immediate decrease in atp concentration. 4,9,21,36 only limited amounts of pc (~70 90 mmol.kg -1 dry muscle) are stored, and maximal intensity exercise rapidly depletes it, slowing pc contribution to atp resynthesis and concomitantly augmenting the stimulation of other bio-energetic pathways. 2,4,9,21 creatine also has other important physiological functions, including buffering free intracellular protons and coupling mitochondrial oxidative resynthesis of atp to its cytosolic hydrolysis – the so-called creatine phosphate shuttle. 1,2,4,36 a sizable amount of research has been conducted on the effect of creatine supplementation on physical performance. it has been reported that there are benefits to enhancing the skeletal muscle store of creatine. these include improved maintenance of maximal power outputs, 1,2,4,5,17,18,31 more rapid recovery from high-intensity exercise, 14,15,27,35,36 and diminished post-exercise muscular pain. 35,36 creatine supplementation in combination with high-intensity exercise training has been shown to improve short-term power output, and is reportedly most beneficial for maximising repeated high-intensity work performance. 1,2,5,16,31,36 such activities as resistance training, 35 and all-out intensity cycling, 8 sprinting, 11 jumping, 36 swimming 10 and rowing 29 are sited as benefiting, while some researchers have reported benefits in clinical rehabilitation. 1,18 even short-term creatine supplementation (4 6 weeks) has been associated with improved power output in single original research article high-intensity exercise and recovery during short-term supplementation with creatine plus a protein-carbohydrate formula j r clark (bsc (hons)(human physiology), ba (hms)(hons)(biokinetics), cscs (nsca)) department of biokinetics, sport and leisure sciences, institute for sport research, university of pretoria abstract objective. to determine the effect of short-term creatine supplementation plus a protein-carbohydrate formula on high-intensity exercise performance and recovery. design. a repeated-measures, experimental study, employing a randomised, double-blind, placebo-controlled, group comparison design was used. interventions. thirty active but not sprint-trained male subjects were randomly assigned to 1 of 3 groups: creatine plus protein-carbohydrate formula (crf); creatine only (cre); and control (con). all groups were exposed to the same high-intensity sprint exercise programme, 3 times per week for 30 days. main outcome measures. dependant variables included total repeat sprint distance, fatigue index, perceived muscle pain, and blood lactate, urea, creatine kinase, and cortisol concentrations. results. all groups significantly (p ≤ 0.05) increased total sprint distance and decreased blood urea concentrations. there were no significant changes in blood lactate or cortisol concentrations in any group. crf showed significant decreases (p ≤ 0.05) in fatigue index, muscle pain, and creatine kinase concentration. however, no significant differences were found between groups. conclusion. short-term creatine supplementation with or without protein-carbohydrate supplementation does not appear to enhance performance or recovery significantly over high-intensity exercise training alone in non-sprinttrained individuals. a longer trial period may be required to evaluate effect on recovery more conclusively. in addition, the prime importance of physical conditioning, and in particular task-specific exercise training, in stimulating performance and recovery adaptations is highlighted. correspondence: j r clark institute for sport research lc de villiers sport centre university of pretoria tel: 012-420 6033 fax: 012-420 6099 e-mail: jimmy.clark@up.ac.za sajsm vol 18 no. 4 2006 137 and repetitive maximal exercise tasks lasting less than 30 seconds. 1,2,4,36 in repeated bouts of high-intensity exercise, creatine supplementation attenuated fatigue 17 and resulted in better sustained power output over the duration of an exercise set. 1,36 since atp and pc stores are limited, it seems reasonable to hypothesise that increasing the concentration of free creatine and pc within skeletal muscle may improve performance in maximal work demanding these substrates for rapid atp resynthesis. greater levels of intracellular creatine may also result in improved pc resynthesis during the recovery period, maximising power output in subsequent efforts. 1,36 it has also been hypothesised to act as a buffer to muscle cell acidity during high intensity work. 2 for athletes, a notable reported benefit of creatine supplementation is enhanced recovery from high-intensity work. 1,14,21,27,36 carbohydrate replenishment following exercise is widely recommended as a means to enhance the recovery process. 2,4,5,21 combined carbohydrate and protein supplementation has been shown to enhance recovery following endurance exercise, with more rapid replenishment of muscle glycogen, 12 reduced muscle soreness, 23 and improved performance in subsequent bouts of exercise. 25 more specifically, addition of protein seems less beneficial when sufficient carbohydrate is ingested, 3,13 although addition of even small amounts of essential amino acids to carbohydrate may enhance recovery. 6 it is unclear whether combined protein-carbohydrate supplementation enhances recovery from high-intensity sprint exercise, although the coingestion of carbohydrate and amino acids has been shown to stimulate net muscle protein synthesis following resistance exercise. 24 combining creatine supplementation with protein and carbohydrate supplementation is sometimes promoted by dietary supplement manufacturers as maximising work performance while improving recovery following exercise training. this supplementation strategy is claimed to enhance the training effect. however, scientific investigations are required to validate such claims. therefore, the purpose of this pilot trial was to investigate the effect of creatine supplementation versus creatine combined with a proteincarbohydrate formula on high-intensity exercise performance and recovery. methods subjects thirty male subjects volunteered for the study. all were healthy physical education students with the following characteristics (mean ± standard deviation (sd)): age 20.0 ± 2.0 years, stature 179.4 ± 6.4 cm, body mass 77.4 ± 14.3 kg, body mass index (bmi) 23.9 ± 3.5 kg.m -2 , sum of 7 skinfolds 91.8 ± 53.2 mm. all were moderately active, reporting physical exercise 2 3 days per week. none of the subjects had any recent history of orthopaedic injury, hepatic or renal impairments. in addition, none of the subjects reported use of any nutritional supplement containing creatine, carbohydrate or protein, or any other supplement, within the 3 months prior to the study. the research protocol was approved by the research proposal and ethics committee of the university of pretoria. prior to participation subjects were thoroughly briefed regarding the benefits and risks associated with the study, whereafter written informed consent was obtained. procedures all data collection was carried out at the institute for sport research, university of pretoria. an experimental study was undertaken, employing a randomised, double-blind, placebocontrolled, group comparison design. 33 subjects were randomly assigned to 1 of 3 groups: creatine plus a proteincarbohydrate formula (crf, n = 10); creatine only (cre, n = 10); and control (con, n = 10). all subjects underwent testing before and after 30 days of supplementation and repeat sprint exercise training. the pre-test and post-test sessions were each conducted over 2 consecutive days. on day 1, subjects completed a high-intensity sprint running performance test. day 2 involved blood sampling and evaluation of perceived muscle pain. running performance measures involved analysis of repeat sprint performance, while recovery measures assessed perceived muscle pain and blood markers of muscle damage the day after highintensity running exercise. a time line for events in the study is outlined in fig. 1. physical testing preliminary testing of subjects involved body mass, stature, and skinfold measurement (harpenden caliper, baty international, british indicators) which were used to calculate bmi and sum of 7 skinfolds. 26 thereafter, subjects engaged in a standardised 10-minute warm-up consisting of selfpaced easy running, static stretching and dynamic drills. subjects then performed a maximal-effort, repeated sprint running test, involving 10 x 10-second maximal sprints, with 90 s walk recovery between each sprint. this protocol is similar in intensity, volume, and work-rest ratio to others used to assess efficacy of creatine supplementation in a large number of reported studies. 36 subjects sprinted on a level, even, grass surface, in a straight line, with markers along the length of the run. strong verbal encouragement was given throughout to motivate maximum performance. the distance run in each 10 s sprint was recorded to the nearest metre, s sprint was recorded to the nearest metre, sprint was recorded to the nearest metre, and the sum of the total sprint distance in the 100 s was s was was calculated. also, the individual sprint distances were used to calculate a sprint fatigue index (%) as follows: fatigue index = (max – min) / max x 100, where max is the greatest distance (m), and min is the shortest distance (m) achieved in any single 10 s sprint. blood lactate concentration ([la]b) was measured directly following completion of the test using a lactate pro (arkray, inc. shiga, japan) portable blood lactate meter, using finger capillary blood obtained using standard methods as described by maw et al. 20 all physical testing was performed at the same time of day on each test occasion. subjects were instructed to arrive well rested for the test days, and to avoid physical exercise on the day prior to, and after, physical testing. 138 sajsm vol 18 no. 4 2006 pain assessment and blood analysis the morning after the day of physical testing subjects reported for pain score assessment and blood sampling. this took place at the same time of day on each occasion, and subjects arrived fasted. perceived local leg muscle pain was evaluated by means of a visual analogue scale (vas). vass have been validated for assessment of pain 28 and their use is widespread. 7,19 subjects were asked to report their perceived muscle soreness experienced during activities of daily living (adl) following sprint testing. scores were obtained for perceived leg muscle pain in the last 24 hours prior to the pain assessment (vas24h) and for pain at that moment of assessment (vasnow). blood samples were obtained and analysed for blood urea ([urea]b), creatine kinase ([ck]b) and cortisol ([cortisol]b) concentrations. exercise sessions all 3 groups were exposed to the same physical conditioning programme, consisting of high-intensity repeated sprint running exercise, exactly the same as that used in the physical testing i.e. 10 x 10 s repeated maximal sprints with 90 s recovery between each sprint. these were conducted 3 days per week in supervised sessions to encourage maximal effort in training. supplementation supplementation commenced after the first set of blood samples were taken on day 2 of the study and continued for 29 days. crf received creatine plus a commercially available protein-carbohydrate formula; cre received creatine only; and con received placebo. creatine monohydrate was provided, with doses approximating 0.3 g.kg -1 body mass for the first 7 days, and 0.03 g.kg -1 thereafter, as widely reported to maximise skeletal muscle stores. 1,5,36 in addition to the creatine, crf received a ~30 g serving of a protein-carbohydrate blend (whey protein, calcium caseinate, maltodextrin) twice daily, as recommended by the manufacturers, which approximated 110 kcal per serving, and comprised 60% protein, 20% carbohydrate by volume. all subjects received instructions on individual dosage, as well as a supplementation log book to mark adherence to the supplementation and to record side-effects. subjects were instructed to take the first serving in the morning, and the second serving within 30 minutes of completion of their sprint training or in the afternoon on non-training days. subjects were instructed to maintain their habitual diets. data analysis data analysis procedures included descriptive and inferential statistics. the latter involved friedman’s rank test for k correlated samples for differences between tests within the same group and the kruskal-wallis one-way analysis of variance for differences between groups on the dependant variables at both intervals. 33,34 all differences were reported on the 5% level of confidence (i.e. p ≤ 0.05). dependant variables included total repeat sprint distance, fatigue index, [la]b, vas24h, vasnow, [urea]b, [ck]b, and [cortisol]b. results table i presents the mean variables for all groups. no statistically significant differences were found between the 3 groups with regard to all repeat sprint measures (total distance, fatigue index, or [la]b). across time, all 3 groups showed significant increases in their total sprint distances. even though there was a decrease in fatigue index scores in all 3 groups, crf was the only group to show a statistically significant decrease (p ≤ 0.05) from pre-test to post-test. no significant differences were found between groups on all perceived leg muscle pain measures. crf showed a significant decline in vas24h from pre-test to post-test. the other groups showed the same trend but with no statistically significant differences. cre showed a significant decrease in vasnow. the same tendency was found for the other 2 groups, but without statistical significance. cre had significantly lower scores than the other 2 groups on all measurements of [urea]b. no significant differences were found regarding [cortisol]b or [ck]b amongst the groups. over time, there were significant decreases in [urea]b scores in all 3 groups. no significant changes took place in [cortisol]b. only crf had significant decreases in [ck]b scores from the pre-test to the post-test. discussion lack of statistically significant differences in repeat sprint measures between groups at the post-test is perhaps not surprising, since none of the subjects were sprint trained. physiological adaptations to the sprint programme alone may fig. 1. time line of events. sajsm vol 18 no. 4 2006 139 explain the large improvement in all groups over the short trial period. these may include improved motor unit recruitment and synchronisation, but also increased intracellular pc and muscle glycogen concentration, and improved activity of the enzymes involved in their degradation and resynthesis. 4,21 all groups showed a trend towards lower fatigue index scores. the same adaptations above could explain this reduced fatigue. interestingly, only crf showed a significantly lower fatigue index from pre-test to post-test. no significant changes were found in [la]b within any group over the period of the study. higher blood lactate concentrations may have been expected given the observed improvement in power output (total distance in 100 s). however, a variety of factors can influence blood lactate, and measures should be interpreted with caution. these include rate of change in exercise intensity, carbohydrate levels, exercise mode, monitoring precision, temperature, overtraining, and muscle damage. 32 the lack of significant changes in [la]b despite an average ~12% higher total sprint distance across all 3 groups may in itself be significant, with improved lactate oxidation a possible mechanism. crf and cre showed statistically meaningful declines in vas24h and vasnow, respectively. once again though, changes were not sufficient to result in any significant differences between groups. it was theorised that supplementation with creatine and protein-carbohydrate may improve recovery by stimulating net protein synthesis while ensuring available precursors for structural repair and improved fibre integrity. while this may indeed contribute to reduced post-exercise muscle pain and discomfort, the physiological adaptations to sprint exercise discussed above may alone result in reduced exercise-induced tissue damage and perceived pain, through a variety of mechanisms, such as increasing the motor unit pool exposed to the work. 2 since even con showed a trend towards far lower leg muscle pain or discomfort as measured by vas, the latter explanation may be the more important. selected blood variables were measured that may reflect injury, recovery, or stress. since all groups showed lower (p ≤ 0.05) values for [urea]b at the post-test, this may also be the result of training adaptations, specifically reduced postexercise protein degradation or increased protein synthesis. no differences between groups were observed that could point to a supplementation effect. differences in levels of urea metabolism are likely due to individual differences in protein turnover. the significantly lower [urea]b for cre at both tests may be due to the small sample size. the same can be said for the isolated differences found in [ck]b. no significant differences were found between groups or between tests for [cortisol]b, although this might not be surprising considering the complex nature of the hormone’s response. 30 intense muscular exercise results in skeletal muscle fibre damage. 2,4,21,30 damage to the sarcolemma may result in the appearance of ck in the extracellular environment. 2 interestingly, a significant decrease was observed in [ck]b values in crf, with a similar yet not significant trend appearing in cre and con. this may indicate reduced muscle damage from intense exercise following a period of training, a trend which, interestingly, parallels the observation in perceived muscle pain discussed above. conclusions elite sports performance requires intense training, often on a daily basis, and optimal recovery is vital for performance gains and maintaining training intensity. if the diet is inadequate to meet the athletes’ requirements, correct nutritional supplementation use may have an important role to play. 4,5,16,21 whether this involves creatine with or without a protein-carbohydrate formula, optimal strategies need to be elucidated. although prompting interesting speculation, the present results cannot serve as the basis for concluding a cause-and-effect relationship between short-term creatine table i. repeat sprint performance, perceived muscle pain, and blood concentration measures (mean ± sd) before and after 30 days of supplementation and high-intensity sprint training crf cre con pre-test post-test pre-test post-test pre-test post-test total distance (m) 612.5 ± 51.4 671.5 ± 59.2 * 621.8 ± 74.4 712.0 ± 32.5 * 627.8 ± 35.2 698.1 ± 29.2 * fatigue index (%) 21.2 ± 5.8 11.7 ± 4.7 * 21.2 ± 10.2 15.4 ± 4.8 23.4 ± 13.1 14.0 ± 2.6 lactate (mmol.l -1 ) 15.1 ± 1.3 13.3 ± 1.8 14.6 ± 1.2 15.4 ± 4.8 13.9 ± 0.8 13.2 ± 2.4 vas24h (mm) 41.1 ± 21.5 12.4 ± 9.3 * 34.2 ± 25.4 8.7 ± 9.1 47.0 ± 25.8 13.7 ± 17.0 vasnow (mm) 22.3 ± 17.1 7.1 ± 6.7 38.2 ± 29.2 8.0 ± 12.9 * 35.1 ± 25.1 9.5 ± 10.2 urea (mg.dl -1 ) 43.4 ± 6.5 31.8 ± 5.9 * 38.3 ± 4.7 + 23.8 ± 3.6 +* 50.0 ± 15.4 30.4 ± 8.4 * ck (u.l -1 37°c) 1 720 ± 2 268 465 ± 318 * 871 ± 478 799 ± 763 2 002 ± 2 683 1 408 ± 1 567 cortisol (nmol.l -1 ) 525 ± 135 556 ± 133 490 ± 160 577 ± 176 488 ± 176 553 ± 215 * significantly different from pre-test value, p ≤ 0.05. + significantly different from other groups, p ≤ 0.05. crf = creatine plus protein-carbohydrate formula; cre = creatine only; con = control (placebo); ck = creatine kinase; vas24h = perceived muscle pain over the last 24 hours; vasnow = perceived muscle pain at the moment of assessment. 140 sajsm vol 18 no. 4 2006 plus protein-carbohydrate formula supplementation and improved high-intensity exercise performance or recovery. factors which may have contributed to this and which have been proposed in other studies include a placebo effect, the relatively small magnitude of any treatment effect, and the unfamiliarity of the exercise task. 1 it is suspected that a longer trial period with a larger, sprint-trained sample may more clearly highlight any possible differences. future work should consider use of alternative study designs, athletic abilities, and other indicators of stress, tissue damage, and recovery. certainly though, the importance of the training stimulus in adaptations is demonstrated, at least with regard to non-sprint-trained individuals. athletes and coaches, and those starting training programmes would do well to keep this in mind when considering claims from dietary supplement manufacturers. acknowledgements the author would like to thank the staff of the institute for sport research, university of pretoria, for their assistance in administration of the study. references 1. american college of sports medicine roundtable. the physiological and health effects of oral creatine supplementation. med sci sports exerc 2000; 32: 706-17. 2. �strand po, rodahl k, dahl ha, stromme sb. �strand po, 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is defined as poor optimisation and functioning of multiple joints, muscles, tendons, nerves and bones due to the work environment.[1] wrmsds are induced by postural defects, repetitive tasks, environmental factors, and prolonged stresses and strains experienced in long-distance driving.[2] one of the consequences of these disorders is an increase in absenteeism, which places an economic strain on the employer and the employee.[3] wrmsds have become multifaceted and a global phenomenon, accounting for 42-48% of work-related musculoskeletal illnesses.[2] risk factors associated with wrmsds include uncomfortable seats,[4] vibration exposure[5] and maladroit postures.[6] long-distance driving involves repetitive tasks, such as handling, bending and prolonged sitting, which may place excessive stress along the kinetic chain and affect the driver’s personal and social life.[2] a study in ghana revealed 71 % of minibus drivers sustained wrmsds. lower back and upper back pain constituted 34 % and 17 % of injuries respectively.[1] a recent international study revealed neck pain and upper limb wrmsds were prevalent in bus drivers compared to other anatomical skeletal structures.[7] back and neck disorders were prominent in long-distance bus drivers.[8] this was associated with chronic pain and early retirement.[8] there are no data on wrmds in long-distance drivers in south africa. therefore, the aim of this study is to determine the prevalence of wrmsds among a sample of bus drivers employed at a bus company located in tshwane, south africa. methods study design and procedure a descriptive survey study was conducted to determine the prevalence of wrmsds among male long-distance bus drivers. eighty-nine participants were selected to participate in the study. participants were between the ages of 20 to 65 years, and were included in the study if they were permanent drivers, had a valid code c drivers licence and at least nine years of experience. participants were excluded if they had sustained musculoskeletal disorders from macro-traumatic incidents (e.g. motor vehicle accident, acute traumatic sports injury). ethical clearance for this study was obtained from the tshwane university of technology, faculty committee for research ethics (fcre 2015/06/013). the data were collected using the nordic musculoskeletal questionnaire (nmq) [9] to investigate the prevalence of wrmsds among the participants. the nmq was chosen because of its widespread validity, and as a reliable cost-effective means of determining self-reported musculoskeletal disorders.[9] the bus company assisted in drafting a roster of available participants and communicated the available times and dates to the researcher. the researcher was present on the available days to administer the questionnaire. the researcher was the translator, assisting the participants in understanding the purpose of the study and other aspects of the questionnaire. each participant was requested to sign an informed consent form prior to the commencement of the study. the questionnaire was administered during their break time from driving, and the participants completed it in a private environment to ensure confidentiality. the participants were instructed not to write their names on the questionnaires, thereby ensuring anonymity. the completed questionnaires were placed in a large box for further analysis by the researcher. background: work-related musculoskeletal disorders (wrmsds) contribute to poor posture and prolonged stress and strain due to work demands and the environment. objective: the objective of the study was to determine the prevalence of wrmsds in long-distance bus drivers. methods: a cross-sectional survey study was conducted to determine the prevalence of wrmsds among male longdistance bus drivers. eighty-nine participants were selected from a reputable bus company in pretoria to participate in the study. the nordic musculoskeletal questionnaire (nmq) was used to determine self-reported wrmsds. results: the average age of the participants was 45 years, with a mean height and weight of 1.69 m and 85.4 kg respectively. participants in the study had a mean body mass index of 29.9 kg.m-2, categorising them as overweight. from the bus drivers who reported wrmsds due to driving (22%), most of the pain was noted in the upper back (44%), followed by lower back (42%), neck (42%), shoulder (37%), and wrist/hand (31%). a strong, positive association existed between ankle and knee pain using kendall’s tau-b correlation (τb = .71, p = .0001). a moderate and positive association was further noted between pain in the neck/shoulder (τb = .59, p = .0001) and upper back/shoulder (τb = .59, p = .0001). conclusion: the greatest proportion of pain was experienced along the axial skeleton in long-distance bus drivers. upper back pain was the most prevalent of the wrmsds reported in these drivers. keywords: maladroit postures; musculoskeletal pain; kinetic chain; axial skeleton; appendicular skeleton s afr j sports med 2016;28(2):55-58.doi: 10.17159/2078-516x/2016/v28i2a1109 mailto:rugbeern@tut.ac.za http://dx.doi.org/10.17159/2078-516x/2016/v28i2a1109 original research sajsm vol. 28 no. 2 2016 56 data analysis the descriptive characteristics of the long-distance bus drivers (frequency tables, means and standard deviations) were analysed using the statistical package for social science version 18.0 (spss) for windows to determine the prevalence and variance of wrmsds. kendall’s tau-b was used to provide information regarding the strength of association between the various outcomes variables. the level of significance was set at p ≤ 0.05. results a total of 89 long-distance bus drivers participated in the study. the mean age of the participants was 45 years. their mean height and mass was 1.69 m and 85.4 kg respectively. their body mass index was 29.9 kg.m-2, categorising them as overweight. in this study, 77 % of participants were married and 80 % were non-smokers. the majority of the participants had completed secondary school education (60 %). the participants were well-experienced long-distance drivers; with 93 % having five years and more experience. from the total number of participants in the study (n = 89), a large percentage of participants (38 %) drive for more than 12 hours at a time. only 22 % of all participants (n = 89) selfreported wrmsds as a result of driving. paradoxically, 67 % of the 89 participants indicated that they do experience symptoms of wrmsds as a result of driving (table 1). pain was the common symptom (73 %) experience by the participants (table 1). when the responses of the bus drivers who reported wrmsds (22 %) were analysed, the greatest discomfort or pain was in the upper back (44 %), lower back (42 %), neck (42 %), shoulder (37 %), and wrist/hand (31 %) (figure 1). minimal pain and discomfort was evident in the elbow (20 %), hips/thighs (24 %), knees (23 %), and ankle (24 %) (figure 1). fig. 1: prevalence of region of pain in long-distance bus drivers who has reported wrmsd there was a weak, positive correlation between musculoskeletal disorders and body mass index (bmi), which was not statistically significant (τb = .13, p = .14). a weak correlation was further noted between wrmsds and vibration exposure (τb = .25), seat comfort (τb = -.25), and driving duration (τb = .06). there was a strong, positive correlation between ankle discomfort and knee pain, which was statistically significant (τb = .71, p = .0001). a moderate correlation existed between pain in neck/shoulder, upper back/shoulder, lower back/pelvis and elbow/wrist (table 2). discussion the first finding of this study was that the most prevalent table 1. occupational profile of participants characteristics n (%) males 89 (100) marital status married 68 (77) divorced 5 (6) never married 15 (17) smoking history smoker 9 (10) non smoker 70 (80) ex-smoker 9 (10) what level of education was completed? primary school complete 2 (2) secondary school complete 52 (60) higher degree completed 32 (37) bachelor degree and above 1 (1) how long have you been driving? < 5 years 6 (7) 5 years and more 83 (93) which type of vehicle do you drive? 5 ton 2 (2) >5 ton 87 (98) how much of time you drive daily? less than 8 hours 11 (12) 8-10 hours 25 (28) 10-12hours 19 (21) more than 12 hours 34 (38) is there vibration exposure during driving? yes 24 (28) no 62 (72) have you had any musculoskeletal disorder due to driving? yes 19 (22) no 69 (78) do you experience symptoms? yes 60 (67) no 29 (33) what word best describes your symptoms? pain 44 (73) ache 7 (12) cramp 5 (8) stiffness 4 (7) original research 57 sajsm vol. 28 no. 2 2016 wrmsds were upper back followed by neck, lower back, shoulders, ankle, pelvis, wrist/hand, knee and elbows. this finding is similar to that found in a study conducted in ghana [1], which concluded the most prevalent wrmsds were lower and upper back. therefore, the current study creates an awareness that upper back disorders are highly prevalent among bus drivers in south africa. the next finding was that there was a mismatch between reported wrmsds and symptoms experienced due to driving. several drivers reported no wrmsds due to their driving; however, they reported experiencing symptoms, particularly pain, after driving. this suggests that wrmsds are masquerading as symptoms experienced by drivers. several bus drivers were overweight. the low correlation between bmi and wrmds suggests factors other than being overweight were associated with wrmds. however, an elevated bmi predisposes one to cardiovascular disease [10] and road accidents. [11] an elevated bmi predisposes bus drivers to a slumped seated posture, contributing to muscle imbalance and pain. [12] cardiovascular disease, especially hypertension, is prevalent in long-distance bus drivers. this is due to poor lifestyle choices adopted by drivers, such as irregular eating habits, sitting for prolonged periods and low physical activity.[10] although not investigated in this study, interventions targeted at reducing bmi may assist in reducing the risk of cardiovascular disease and road accidents. a moderate correlation between pain in the neck and shoulders and upper back and shoulders were noted in longdistance bus drivers. excessive protrusion of the neck may narrow and degenerate the intervertebral foramen predisposing drivers to neurological pathology.[13] upper crossed syndrome is characterised by the hypertonic upper trapezius, levator scapulae, and pectoralis muscles, as well as inhibition of the deep cervical flexors, rhomboids, and serratus anterior, which may affect scapulothoracic joint movement.[14] as a result of this muscle imbalance, inadequate function of the scapulothoracic and glenohumeral joints may lead to superior humeral elevation and poor neuromuscular control.[15] , thus predisposing the drivers to secondary impingement syndrome. as a result of prolonged sitting the iliopsoas muscle may become hypertonic, resulting in reciprocal inhibition of deep abdominal, interspinous, and gluteus muscle groups contributing to reduced stability and extensor mechanism dysfunction.[16] this may increase the risk of mechanical, lower back pain in long-distance bus drivers. longitudinal intervention studies, incorporating these associations in a physical therapy plan targeted at long-distance drivers, will preserve function, improve efficiency and reduce the incidence of musculoskeletal pathology. conclusion upper back pain was the most prevalent wrmsd in longdistance bus drivers residing in tshwane. bus drivers were unware that the underlying symptoms experienced due to driving may be masquerading as wrmds. this often prevented them from seeking medical attention. several bus drivers were overweight. elevated bmi may predispose drivers to an increased risk of cardiovascular disease and road accidents. future intervention studies should consider the association and the interrelationship between various muscle groups and their effect on joint function. these studies should also incorporate these associations in a physical therapy/rehabilitation plan targeted at long-distance drivers. acknowledgements: tshwane university of technology and the bus company for granting us permission to conduct the research. conflict of interest: no conflict of interest references 1. abledu jk, offei eb, abledu gk. occupational and personal determinants of musculoskeletal disorders among urban taxi drivers in ghana. int sch res notices 2014; 2014:517259. 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[http://dx.doi.org/10.1093/occmed/kqr024] [pmid: 21525071] 3. guo hr, chang yc, yeh wy, et al. prevalence of musculoskeletal disorder among workers in taiwan: a nationwide study. j occup table 2. association between wrmsd and various outcome measurements variable number correlation coefficient significance (p) wrmsd and bmi 88 .13 .14 wrmsd and vibration exposure 86 .25 .02 wrmsd and seat comfort 87 -.25 .02 wrmsd and driving duration 88 .06 .52 ankle and knee 89 .71 *.0001 neck and shoulder 89 .60 *.0001 upper back and shoulder 89 .59 *.0001 lower back and pelvis 89 .53 *.0001 elbow and wrist/hand 89 .58 *.0001 note: work-related musculoskeletal disorders (wrmsds) r ≤ .3 weak correlation, .3>r ≤ .7 moderate correlation, r > 0.7 strong correlation significance *p≤.05 original research sajsm vol. 28 no. 2 2016 58 health 2004;46(1):26-36. [http://dx.doi.org/10.1539/joh.46.26] [pmid: 14960827] 4. alperovitch-najenson d, katz-leurer m, santo y, et al. upper body quadrant pain in bus drivers. arch environ occup health 2010;65(4):218-223. [http://dx.doi.org/10.1080/19338244.2010.486422] [pmid: 20450125] 5. bovenzi m. metrics of whole-body vibration and exposure-response relationship for low back pain in professional drivers: a prospective cohort study. int arch occup environ health 2009;82(7):893-917. [http://dx.doi.org/10.1007/s00420-008-0376-3] [pmid: 18953559] 6. albert wj, everson d, rae m, et al. biomechanical and ergonomic assessment of urban transit operators. work 2014;47(1):33-44. [http://dx.doi.org/10.3233/wor-131683] [pmid: 24004743] 7. rugulies r, krause n. effort-reward imbalance and incidence of low back and neck injuries in san francisco transit operators. occup environ med 2008;65(8):525-533. [http://dx.doi.org/10.1136/oem.2007.035188] [pmid: 18056748] 8. okunribido oo, shimbles sj, magnusson m, et al. city bus driving and low back pain: a study of the exposures to posture demands, manual materials handling and whole-body vibration. appl ergon 2007;38(1):29-38. [http://dx.doi.org/10.1016/j.apergo.2006.01.006] [pmid: 17225292] 9. de barros en, alexandre nm. cross-cultural adaptation of the nordic musculoskeletal questionnaire. int nurs rev 2003;50(2):101-108. [http://dx.doi.org/10.1046/j.1466-7657.2003.00188.x] [pmid: 12752909] 10. shin sy, lee cg, song hs, et al. cardiovascular disease risk of bus drivers in a city of korea. ann occup environ med 2013;25(1):34. [ http://dx.doi.org/10.1186/2052-4374-25-34] [pmid: 24472511] 11. wiegand dm, hanowski rj, mcdonald se. commercial drivers' health: a naturalistic study of body mass index, fatigue, and involvement in safety-critical events. traffic inj prev 2009;10(6):573579. [http://dx.doi.org/10.1080/15389580903295277] [pmid: 19916128] 12. dabrh ama, firwana b, cowl ct, et al. health assessment of commercial drivers: a meta-narrative systematic review. bmj open 2014;4: e003434. [http://dx.doi.org/10.1136/bmjopen-2013-003434] [pmid: 24604478] 13. jackson r. the classic: the cervical syndrome. clin orthop relat res 2010;468(7):1739-1745. [http://dx.doi.org/10.1007/s11999-010-1278-8] [pmid: 20177837] 14. page p, frank c, lardner r. assessment and treatment of muscle imbalance: the janda approach. 1st ed. united states: human kinetics, 2010: 175-213. 15. celik d, sirmen b, demirhan m. the relationship of muscle strength and pain in subacromial impingement syndrome. acta orthop traumatol turc 2011;45(2):79-84. [http://dx.doi.org/10.3944/aott.2011.2425] [pmid: 21610305] 16. prentice we. rehabilitation techniques for sports medicine and athletic training. 6th ed. boston: slack incorporated, 2015:127 review 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license end-to-end sars-cov-2 transmission risks in sport: current evidence and practical recommendations b jones,1,2,3,4,5 phd; g phillips,1,2,6 mbchb, msc; f valeriani,7 phd; t edwards,8 phd; er adams,8 phd; l bonadonna,9 phd; rj copeland,10 phd; mj cross,11,12 phd; c dalton,10 phd; l hodgson,13,14 phd; a jimenez,10,15 phd; sp kemp,16,17 mbbs, msc; j patricios,18 mbbch ffsem (uk); v romano spica,7 phd; ka stokes,11,16 phd; m weed,19 phd; c beggs,1 phd 1 carnegie applied rugby research (carr) centre, carnegie school of sport, leeds beckett university, leeds, uk 2 england performance unit, the rugby football league, leeds, uk 3 leeds rhinos rugby league club, leeds, uk 4 division of exercise science and sports medicine, department of human biology, faculty of health sciences, the university of cape town and the sports science institute of south africa, cape town, south africa 5 school of science and technology, university of new england, armidale, nsw, australia. 6 hull kingston rovers, hull, uk 7 public health unit, department of movement, human and health sciences; university of rome “foro italico”, rome, italy 8 department of tropical disease biology, liverpool school of tropical medicine, pembroke place, liverpool, l3 5qa, uk 9 italian national institute of health, rome italy 10 advanced wellbeing research centre, sheffield hallam university, uk 11 university of bath, bath, uk 12 premiership rugby, twickenham, uk 13 the football association, st george’s park, burton-upon-trent, uk. 14 school of clinical and applied sciences, leeds beckett university, leeds, uk 15 centre for sport studies, king juan carlos university, fuenlabrada, madrid, spain 16 rugby football union, twickenham, uk 17 london school of hygiene and tropical medicine, london, uk 18 wits sport and health (wish), school of clinical medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 17centre for sport, physical education and activity research (spear), canterbury christ church university, uk corresponding author: b jones (b.jones@leedsbeckett.ac.uk) the coronavirus disease 2019 (covid-19) pandemic has caused disruption to professional and recreational sports across the world.[1] the causal agent of covid-19 is the severe acute respiratory syndrome coronavirus 2 (sars-cov-2)[2], which is transmitted from human-to-human by multiple pathways.[3,4] the novelty of the sars-cov-2 virus and therefore population susceptibility, in addition to the high transmissibility of the sars-cov-2 virus, ultimately resulted in the covid-19 pandemic.[5] professional and recreational sports are obligated to implement risk management and mitigation strategies to prevent sars-cov-2 transmission and the subsequent covid-19 spread.[6,7] the sars-cov-2 virus can be transmitted by three main routes in sport; respiratory aerosol, droplets and fomites.[8,9] the risks of sars-cov-2 transmission are influenced by the environment in which they occur (fig. 1). all activities, from leaving home, including time spent within the sporting environment, and other associated activities (e.g. meetings and travel) should be considered as sars-cov-2 transmission risks (fig. 2).[10,11] the purpose of this review is to provide an overview of the considerations of end-to-end sars-cov-2 transmission risk and practical steps for risk management within sport. sars-cov-2 transmission via respiratory aerosol and droplets the sars-cov-2 virus can be transmitted by larger the coronavirus disease 2019 (covid-19) pandemic has caused disruption to professional and recreational sports across the world. the sars-cov-2 virus can be transmitted by relatively large respiratory droplets that behave ballistically, and exhaled aerosol droplets, which potentially pose a greater risk. this review provides a summary of end-to-end sars-cov-2 transmission risk factors for sport and an overview of transmission mechanisms to be considered by all stakeholders. the risk of sars-cov-2 transmission is greatest indoors, and primarily influenced by the ventilation of the environment and the close proximity of individuals. the sars-cov-2 transmission risks outdoors, e.g. via water, and from fomites, appear less than initially thought. mitigation strategies include good end-to-end scenario planning of activities to optimise physical distancing, face mask wearing and hygiene practice of individuals, the environment and equipment. the identification and removal of infectious individuals should be undertaken by means of the taking of temperature and covid-19 symptom screening, and the use of diagnostic monitoring tests to identify asymptomatic individuals. using adequate video footage, data from proximity technology and subject interviews, the identification and isolation of ‘close contacts’ should also be undertaken to limit sars-cov-2 transmission within sporting environments and into the wider community. sports should aim to undertake activities outdoors where possible, given the lower sars-cov-2 transmission risk, in comparison to indoor environments. keywords: covid-19, virus, illness, infection s afr j sports med 2021;33:1-17. doi: 10.17159/2078-516x/2021/v33i1a11210 mailto:b.jones@leedsbeckett.ac.uk http://dx.doi.org/10.17159/2078-516x/2021/v33i1a11210 https://orcid.org/0000-0003-0947-0677 https://orcid.org/0000-0001-5997-1387 https://orcid.org/0000-0002-4274-6236 https://orcid.org/0000-0002-8395-0591 https://orcid.org/0000-0003-2606-2288 https://orcid.org/0000-0003-4058-4461 https://orcid.org/0000-0002-0816-2835 https://orcid.org/0000-0002-8586-9965 https://orcid.org/0000-0002-1404-873x https://orcid.org/0000-0003-3891-5540 https://orcid.org/0000-0003-1043-6759 http://orcid.org/0000-0002-3250-2713 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0002-2900-6399 http://orcid.org/0000-0002-5049-2838 https://orcid.org/0000-0002-9768-4677 https://orcid.org/0000-0002-6460-9937 review sajsm vol. 33 no. 1 2021 2 respiratory droplets (>100 µm in diameter) that behave ballistically, and smaller exhaled aerosol droplets (<100 µm in diameter), which potentially pose a greater risk.[12-14] this is because aerosol droplets rapidly evaporate to become small aerosol particles (<50 µm in diameter)[15,16] that can easily be inhaled.[13,17] furthermore, smaller aerosol droplets can travel much further than ballistic droplets on convection air currents. these smaller aerosol droplets pose both a ‘near-field’ and a ‘far-field’ threat. near-field refers to close proximity (e.g. 1–2 m), and far-field is beyond 2 m. near-field sars-cov-2 transmission risks are caused by clouds of exhaled aerosol particles, potentially infecting individuals within close proximity. far-field sars-cov-2 transmission risks occur primarily indoors when aerosol particles have been dispersed by air currents into the wider room space. the near-field transmission risks posed by large respiratory aerosol droplets can be mitigated by physical (or social) distancing, protective screens, and the use of face masks.[18,19] the far-field risks posed by smaller infectious aerosols must be countered either by ventilation which flushes airborne particles from the room space,[19] or potentially by air disinfection which biologically inactivates the sars-cov-2 virus.[20] in addition, thermal plumes, warm convection air currents that surround all individuals, appear to play an important role in the transportation of respiratory aerosols,[21] with exhaled fine aerosol particles rising vertically above the heads of individuals. indoors, the aerosol particles entrained into thermal plumes become trapped by the ceiling and so get recirculated around the room space on convection currents and as such become a sars-cov-2 transmission risk within far-field zones. the transmission risk of the sars-cov-2 virus is far greater indoors than outdoors, primarily due to increased ventilation outdoors. although near-field sars-cov-2 transmission can occur both indoors and outdoors,[22] in the outdoor environment the near-field transmission risk is lower because air velocities are generally higher, with the result that the exhaled aerosol particles will be dispersed more rapidly. this dispersion (dilution) effect becomes less pronounced the closer individuals are to each other. the risk of far-field aerosol transmission is much greater indoors because the concentration of aerosol particles in room spaces builds up over time, particularly in poorly ventilated spaces. the risk is further increased by aerosol particles, which are entrained in thermal plumes, trapped by the ceiling, before slowly descending through the breathing zone due to gravitational deposition. outdoors, these are dispersed upward into the atmosphere, and therefore far-field aerosol transmission is unlikely outdoors given greater ventilation.[23] to determine the sars-cov-2 transmission risk, it is important to define indoor and outdoor environments. this can be challenging in sport due to covered outdoor spaces (e.g. ‘indoor’ stadiums). therefore, evaluating spaces based on near-field and far-field aerosol threat may be more appropriate. in a poorly ventilated communal changing area, both the near-field and far-field threats will be significant, whereas in a large indoor training facility with no ceiling and a high roof space, the far-field aerosol threat will be much less. this is due to the greater volume of the space, thus reduced concentration of sars-cov-2 viral particles potentially inhaled over time. if air movement at low level is poor (i.e. low air velocities) then the near-field threat may still be high, therefore physical distancing and mask wearing could be beneficial. many larger indoor sporting facilities (i.e. arenas) normally contain audiences, in which case, because of the high numbers of people involved, this may result in air and ventilation characteristics behaving similar to an indoor space for covid-19 risk assessment purposes. the risk posed by far-field aerosol transmission of the sarscov-2 virus can be mitigated through improved room ventilation (e.g. opening windows and doors).[24,25] it has been shown that the sars-cov-2 virus survives in aerosols for longer when the air is cooler and drier.[21,26] the viral half-life is >10 times longer outdoors during the winter and autumn months compared with the summer.[25] even though a room space may be heated in winter, the air can still be very dry (e.g. 10-40% relative humidity). the viral load in any droplets inhaled may be substantially greater than would be the case during the summer months.[25] while the implications of this are not yet fully understood, it may explain in part the seasonal variation in covid-19 case numbers that have been observed in many temperate regions. uvb radiation in sunlight has also been shown to rapidly degrade the virus. consequently, covid-19 appears to have a seasonal component,[27] with transmission greatly reduced during the summer months when temperatures and uvb levels are higher and the air is more humid. the probability that far-field transmission events will occur can be determined from the wells-riley equation (equation 1).[28] the probability of acquiring an infection by the airborne route increases as: (i) the number of infectious people present increases; (ii) the quanta generation rate increases; and (iii) the number of people susceptible spend longer in the presence of infectious people. the quanta generation rate, q, cannot be obtained directly, but rather, must be estimated epidemiologically from outbreak data. with respect to this, a fig. 1. sars-cov-2 main transmission routes and risks for sport review 3 sajsm vol. 33 no. 1 2021 quantum of infection is defined as the infectious dose required to infect 63.2% of the susceptible people present.[28] equation 1. where: c is the number of new infection cases; s is the number of susceptible individuals; i is the number of infectors; p is the average pulmonary ventilation rate of a person (m3/s); q is the quanta generation rate of the infectious agent (quanta/s); t is the exposure time (s), and q is the room ventilation rate with clean outside air (m3/s). to reduce the sars-cov-2 transmission risk by the aerosol route in any given context, it is important to minimise the number of people present and the duration of exposure, and maximise the room ventilation rates so that the concentration of infectious particles in the air is reduced.[29-30] it is not always easy to determine room ventilation rates, particularly in situations where natural ventilation is employed. therefore, monitoring carbon dioxide (co2) can be used as a surrogate measure for ventilation in the wells-riley model.[31] sars-cov-2 transmission via fomites fomites may contribute to the transmission of sars-cov-2. high viral loads of sars-cov-2 have been shown to remain viable for up to 72 hours on inert surfaces, whilst undergoing exponential decay.[32] viral decay in culture media is increased at higher temperatures, with the virus remaining infectious for seven days at 22oc, one day at 37oc and 30 minutes at 56oc.[33] temperature is therefore likely to be a key determinant of surface stability. as equipment is commonly shared in numerous sports, this does potentially pose a route of transmission,[34,35] although the likelihood of transferring a sufficient amount of the virus to cause an infection to the mucus membranes of another person remains unclear.[34] viral shedding into the environment has been demonstrated during sars-cov-2 infection. the rooms of hospitalised sars-cov2 patients can be heavily contaminated with sars-cov-2 rna, including frequently touched surfaces, such as sinks and door handles.[36] the transfer of sars-cov-2 rna from the hands of patients to objects has also been documented, demonstrating the environmental contamination originating from infectious individuals.[37] however, most studies have utilised quantitative reverse transcription polymerase chain reaction (rt-qpcr) to detect sars-cov-2 ribonucleic acid (rna) in the environment, rather than demonstrating infectious viral particles using culture. a study of environmental sars-cov-2 in the rooms of quarantining confirmed positive cases found 29/55 surfaces in the rooms of symptomatic cases were positive for sars-cov-2 by rtqpcr; however, no viable virus was isolated in cell culture.[38] as such, the contribution of fomites to the transmission of sars-cov-2 is controversial,[39] and remains relatively unknown,[25] in part due to no minimum infectious dose of sars-cov-2 being established,[40] hampering studies of transmission dynamics from surfaces. the risk of sars-cov-2 transmission via saliva, due to the potential to carry high viral loads,[41] is significant. the risk is greater in sports where spitting is common practice (e.g. in cricket, saliva is often used to shine cricket balls, potentially facilitating the deposition of viral particles from infected players). rna from an inactivated sars-cov-2 virus can be detected from the surface of cricket balls up to one hour postinoculation using rt-qpcr, although viral viability (i.e. the ability to cause infection) cannot be determined using this approach.[35] using live sars-cov-2 viruses, an exponential reduction in detectable sars-cov-2 virions for all inoculated sport equipment (i.e. cricket glove, football, golf ball, horse saddle, rugby ball, tennis ball, gym pit foam) was observed over a short-term period (one minute to 90 minutes).[34] the low inoculum (5.4x102 virions, representing a 40µl saliva droplet from a sars-cov-2 infected player with a viral load in the lower quartile of cases) was only detectable on one (the polyurethane horse racing saddle) of ten materials at five minutes and no virus could be detected on any material after 15 minutes. these findings suggest that from individuals with lower viral loads, there is probably insufficient viral load transferred from fomites to be infectious. the material composition should also be considered when evaluating the risk of sars-cov-2 transfer on sports equipment. for example, edwards et al.[34] found that viral recovery was reduced by absorbent materials, which included leather (e.g. red cricket ball and cricket glove) and polyurethane foam (e.g. gym mat foam). harbourt et al.[42] also demonstrated that viral stability was reduced on absorbent clothing in comparison to skin or plastic materials. the observation that porous materials result in reduced viral recovery and transmission risk can be used to prioritise materials for within-game cleaning or swapping, and focus cleaning efforts to reduce their effect on sporting events.[34] in addition to the material composition of the sports equipment, the specific finish also appears important. for example, considering two bovine leather cricket balls, the ball that had synthetic grease on it had a lower viral recovery than the ball that had a nitrocellulose finish.[34] there is potential for this information to be used by developers of sporting materials to engineer products to be less amenable to viral transmission. the quantification of the viral load that may be transferred from an individual with a sars-cov-2 infection onto sports equipment has not been evaluated. edwards et al.[34] used previously reported concentrations seen in respiratory tract secretions, although the concentrations may be different in practice. a quantitative microbial assessment of the risk of infection from fomites has been performed using the monte carlo simulation.[43] a lower than 1/10 000 infection risk was observed from a single touch of surfaces infected with a range of 1 to 10 000 genome copies/cm2. this supports the potentially limited role of fomites in sars-cov-2 transmission, although further research is still required. sars-cov-2 transmission via water the transmission risk of the sars-cov-2 virus in water is an important consideration during the covid-19 pandemic for sports. sars-cov-2 is an enveloped virus, similar to orthomyxoviridae (e.g. influenza viruses), paramyxoviridae           )( 1 q iqpt esc review sajsm vol. 33 no. 1 2021 4 (e.g. measles virus, mumps virus, respiratory syncytial virus), herpesviridae, coronaviridae (some with low pathogenicity, others with high pathogenicity like sars-cov and merscov). whilst influenza viruses and coronaviruses can be found in trace amounts in faecal material and aqueous environments, waterborne infections have not been recorded.[44-46] coronaviruses may be introduced into aquatic habitats through urban or agricultural runoff or via wastewater effluents, as observed in lake, river and coastal waters.[47-49] these viral units are likely to experience considerable decay and loss of infectivity rapidly after arriving in water.[50] several factors can influence virus survival, vitality and infectious capability in water, which include temperature, presence of suspended solid and organic matter, ph, and water treatments and disinfections.[51] rna fragments of the sars-cov-2 virus have not been detected in treated waters,[52] therefore, current water treatment practices are likely to be effective in virus removal. therefore, water is not considered a major transmission risk of sars-cov-2 for sports, due to the instability of water[53] and susceptibility to oxidants, such as chlorine.[54] transmission risk management considerations for sporting activities fig. 2 presents activities that should be considered as end-toend sars-cov-2 transmission risks within sport. a wider covid-19 management system, including the identification, and removal of infectious and potentially infectious (e.g. individuals exposed to infectious individuals) should also form part of the overall sars-cov-2 risk mitigation strategy. athlete medical and professional care screening and testing for covid-19 the risk of the sars-cov-2 spreading within a sporting environment can be reduced by the implementation of appropriate covid-19 protocols, which aim to identify and prevent symptomatic and asymptomatic individuals entering the environment. the primary symptoms (e.g. loss of taste or smell, new or continuous cough, high temperature [>37.8oc], muscle aches and fatigue,[55]) can be monitored daily, and integrated within routine wellbeing types which are common in sport.[56] the effectiveness of temperature screening with non-contact thermometers, in isolation of other monitoring strategies, has recently been questioned.[57] once symptomatic individuals are identified, they can then receive a consultation with a clinician, and/or be referred for appropriate sars-cov-2 diagnostic testing. asymptomatic and pre-symptomatic individuals with covid-19 can have high viral loads, similar to those with clinical disease, indicating that athletes without symptoms are able to transmit the sarscov-2 virus within a sporting environment.[58] various sarscov-2 diagnostic testing protocols exist to identify symptomatic and pre-symptomatic individuals. the implementation of a testing programme would likely be influenced by both clinical reasoning, cost and logistical considerations. the most sensitive tests for acute sars-cov-2 infection are rt-qpcr assays, which amplify and detect specific sequences of the sars-cov-2 genome. multiple commercial and approved (food and drug administration [fda], conformitè europëenne in vitro diagnostic medical devices [ce-ivd]) assays are available to target either single or multiplex regions of the sars-cov-2 genome.[59] best performing assays can detect sars-cov-2 as low as 100 genome copies/ml.[60] rtqpcr testing requires complex infrastructure, undertaken in specialist laboratories. cycle threshold (ct) values provide a proxy measure of viral load in a rt-qpcr test, with values under 30 considered high and highly infectious, values between 30-40 low, and >40 negative.[61-63] whilst the lack of a more accurate comparator test or ‘gold standard’ makes the true accuracy of rt-qpcr difficult to ascertain,[64] sensitivity is thought to range between 70% and 98%, depending on sample type, gene target, and kit manufacturer.[65-66] the specificity of rt-qpcr is high, with large studies estimating it to lie between 97.4 and 99.1%.[67] whilst rt-qpcr provides a high level of sensitivity, the duration of time from swab to results (e.g. transit to, and processing within a laboratory) and the high commercial cost fig. 2. end-to-end transmission risk activities for sports review 5 sajsm vol. 33 no. 1 2021 (approx. £100 gbp / $140 usd if purchased in united kingdom (uk) or r830 zar / $60 usd if purchased in south africa) means that other diagnostic tests may be preferable. lateral flow tests (lft) are an alternative valid, point-of-care diagnostic tool that can detect individuals with high viral loads, within approximately 15 minutes from swab to test outcome.[68] the cost per lft test is approximately £5 gbp if purchased in uk (approx. $7 usd) or approximately r208 zar if purchased in south africa (approx. $15 usd), significantly less than a rt-qpcr test. in independent evaluations (world health organisation emergency use listing; who-eul) approved tests have >80% sensitivity rising to >95% sensitivity in individuals with high viral load (ct <30) and >98% specificity, although this can vary according to manufacturer.[69] sampling technique is important, given when swabs are self-taken and read by non-professionals, the sensitivity may be as low as 40%.[70] as such, the implementation of lft within sports requires careful planning and appropriate training of any staff taking swabs. lft will not capture all positive cases (due to inability to detect low viral loads) but may be appropriate as part of an asymptomatic monitoring strategy. if one positive lft is detected within a cohort during routine lft asymptomatic monitoring, this can be used as a trigger for a surge in daily testing or for the rt-qpcr testing of individuals or whole squads. furthermore, the sample collection to result duration for sars-cov-2 diagnostic tests may also be a consideration for sports. even though rt-qpcr has a higher sensitivity than lft, the longer sample collection to result duration (15 mins vs. approx. 24-36 hrs) may mean that asymptomatic infectious individuals inadvertently remain within the sporting environment if athletes are training daily. alternative assays exist, including real-time loop mediated isothermal amplification (lamp) technology, where swab and saliva samples can be used with minimal processing and extensive laboratory facilities are not required. the typical time to run this diagnostic test is approximately 20 minutes, from sample collection to result.[71] tests undertaken using lamp technology still require molecular expertise, are not truly point-of-care, and the cost reflects the personnel and equipment required to perform them. in the national institute for health research (nihr)-funded evaluation, lamp testing was 79% sensitive on asymptomatic individuals and 100% specific, although it missed more than 50% of cases in a manchester, uk pilot.[71] there seems to be little, if any, increase in sensitivity from lfts to these simplified molecular tools with no extraction, yet they are more complex and expensive to implement. to avoid false positives results, it may be recommended that individuals who have previously tested positive for sarscov-2 are removed from the testing programme for 90 days, due to residual rna remnants following sars-cov-2 acute infection. re-infection is unlikely in the 90 days following an infection,[72] although the evidence still remains unclear.[73] the rollout of vaccination programmes around the world presents a new challenge for the management of athletes.[74] at present, it is unclear how athletes should be managed within routine diagnostic testing cycles once vaccinated for the sars-cov-2 virus. most vaccination regimens are using two doses to first prime, and then boost immunity.[75] a level of protection is gained from the first vaccination, with a trial of the pfizerbiontech bnt162b2 mrna covid-19 vaccine showing 52% efficacy after the first dose.[76] breakout infections following full vaccination are less severe and likely to be less transmissible.[77,78] there is speculation that vaccinated individuals may still asymptomatically carry sars-cov-2 and contribute to its transmission,[79] although data are lacking in this area and will become available via surveillance studies of vaccinated populations. when determining the appropriateness of a diagnostic test for a specific cohort, it is important to also consider the community prevalence of covid-19.[80] as the prevalence declines, the positive predictive value also declines exponentially. even with a diagnostic test with high sensitivity and specificity, at low population prevalence the results may be false positives, as the positive predictive value becomes small.[67] as such, diagnostic testing should be one part of the overall covid-19 risk management measures. providing safe medical and professional care the near-field and far-field transmission risk of the sarscov-2 virus must be carefully considered in the delivery of safe medical and professional care to athletes in sport. athletes are supported by large multidisciplinary teams, consisting of doctors, physiotherapists, nutritionists, psychologists, and masseurs, among others. determining what care can be safely delivered remotely through telemedicine is the most effective means of mitigating any transmission risk.[81] however, certain situations can only be conducted ‘face-to-face’ and consequently this increases potential sars-cov-2 exposure between individuals at close proximity. care deemed necessary and essential, such as supervised rehabilitation, medical examinations and procedures, must be permitted in a risk-mitigated manner.[82,83] delayed or compromised care could negatively impact an athlete’s wellbeing and sporting performance both in the short and longer term, which may result in prolonged recovery, disablement, and impact a future career opportunity. pre-scenario planning most effectively mitigates the sarscov-2 transmission risk. reducing the duration and frequency of interactions can be effective, as clinical environments tend to be specialised and not easily relocated to optimise environmental conditions. national healthcare guidance on personal protective equipment (ppe) has been interpreted for the sporting setting, taking into account the sport-specific nature, including delivery of pitch-side medical care (table 1),[84,85] with the recommendation that athlete patients also wear a face covering for the duration of review.[82] safe and effective use of ppe is founded on good training to ensure it is worn correctly and the risk of self-contamination is minimised during application and removal (donning and doffing). importantly, for those not of an allied healthcare care profession, in the absence of appropriate training, high grade (i.e., level 3) ppe is of no more protection than a simple face covering. all equipment, including ppe, should be single use where possible and, if reusable, subject to appropriate review sajsm vol. 33 no. 1 2021 6 sanitisation protocols. verbal components of consultations should be conducted with physical distancing respected, breaching this only when essential for examinations and other procedures. aerosolgenerating procedures (table 2) can be a significant source of virus transmission when conducted on infectious individuals, due to the aerosolisation of respiratory droplets.[8] consequently, these situations require a higher level of mitigation, through increasing the standard of ppe, and also the need for a dedicated area to limit the exposure to bystanders, which must be subject to appropriate decontamination after use.[84] establishing a sport-specific injury risk profile can help provide covid-19 safe updates to emergency action plans and thus ensure adequate equipment is available to account for ppe availability and sanitisation protocols for equipment between uses. emergency care poses the greatest challenge, due to the need for a rapid response and propensity for these scenarios to involve aerosol-generating procedures. this can include head injuries which carries the potential for airway compromise and cardiac arrest. both airway intervention and chest compressions are deemed potential aerosol-generating procedures.[86] level 3 ppe can take some time to apply, which impacts on the ability for the medical response team to rapidly respond. depending on resource availability and staff familiarity with donning and doffing, organisations may wish to have staff already prepared in level 3 ppe for high-risk settings in order to prevent any unnecessary delay in delivering prompt emergency care.[84,85] in circumstances where only level 2 ppe is available, or there is a delay in donning level 3 ppe, airway interventions beyond simple manoeuvres are not recommended. in cardiopulmonary resuscitation (cpr), chest compressions can be commenced in addition to the use of an automated external defibrillator, provided that a face covering is applied to the casualty which does not impede airflow (i.e. oxygen mask or light cloth). in youth sport, where cardiac arrest can more commonly be triggered by a respiratory cause,[87] ventilation is crucial to survival. medical teams should discuss how they wish to manage this situation, as a delay could severely impact clinical outcomes for the casualty. outside of elite sports protocols, it may be decided that full cpr will be started in the absence of suitable ppe, at a risk to the responders. however, staff should not be put under undue pressure to compromise their own health and safety in the absence of adequate ppe. training and competition transmission risk during outdoor sporting activities the transmission risk of sars-cov-2 during outdoor sporting activities can be determined based on the proximity, duration of close proximity and whether individuals are directly facing each other.[7,88] these factors determine the risk of infectious respiratory aerosol and droplet particles transferred from table 1. recommended personal protective equipment (ppe) guidance for specific clinical situations that may be encountered in the sporting environment [84,85] medical and professional care player interaction ppe level maintaining physical distancing as advised; no face-to-face contact risk 1 not maintaining 2 m distance; with face-to-face contact risk 2 wound care, excluding oral / dental / nasal injuries 2 uncomplicated concussion evaluation e.g. head injury assessment 2 managing complex injuries, with no c-spine involvement e.g. isolated limb or joint injury 2 medical emergency without potential for airway compromise 2 cardiac arrest* without airway interventions therefore with face covered; includes continuous compressions and automated external defibrillator use 2 performing a nasopharyngeal swab 2 nasal and oral procedures, e.g. epistaxis and oral injuries 3 aerosol generating procedures 3 medical emergency with potential for airway compromise e.g. complicated head injury, choking** 3 cardiac arrest* – with airway intervention, therefore without covered compressions 3 *cardiac arrest scenarios have both options of level 2 and level 3 ppe to accommodate for availability in different situations. **in cases of suspected choking, although level 3 ppe provides the most appropriate protection, it is appreciated that an immediate life-saving intervention may be needed which may preclude donning of the extra garments. in these cases, level 2 protection should be a minimum. table 2. interventions with the potential to be aerosol generating procedures activity 1. cardiopulmonary resuscitation (cpr) 2. airway management: any suction of upper airway, use of airway adjuncts and emergency surgical airway procedures 3. breathing management: any form of manual ventilation; bag-valve-mask ventilation using a viral filter is ideal, while mouth-to-mouth ventilation is not recommended 4. medical emergencies with altered levels of consciousness and a risk of comprising of the airways are potentially aerosol-generating procedures 5. nose and throat procedures, such as managing nasal epistaxis or oral lacerations note: nebulising, high flow oxygen administration via facemask, nasopharyngeal swabbing and defibrillation are not considered aerosol generating procedures. review 7 sajsm vol. 33 no. 1 2021 human-to-human. outdoor team sports, which include a large number of prolonged close interactions, or encounters between athletes outdoors (e.g. start or end of a race) pose a potential risk for human-to-human sars-cov-2 transmission. whilst sars-cov-2 transmission during close proximity prolonged interactions outdoors is plausible, to date there has not been any confirmed transmission observed in sport (e.g. rugby league and soccer), despite infectious players inadvertently participating.[10,89,90] during training and match play, it would be assumed that participants have an increased respiration rate due to the demands of exercise, and thus a substantial increase in aerosol expiration.[91] deep exhalation causes a 4to 6-fold increase in aerosol particle concentration, and rapid inhalation increases aerosol particle concentration by a further 2to 3-fold.[92] consequently, the physiological demands of training and match play increases the sars-cov2 transmission risk in comparison to rest, given the increased rate and concentration of infectious particles being expired. during most sporting activities outdoors, the environmental conditions will likely mitigate the risk of sars-cov-2 transmission via expired infectious particles. the very high ventilation rates experienced outdoors, together with higher air velocities, will disperse and dilute the infectious respiratory aerosol particles, thus reducing their concentration prior to inhalation. the closer the proximity between individuals and the longer the duration of the close proximity interactions, the greater the transmission risk of sars-cov-2, even when outdoors.[7,93] some outdoor sporting activities may create indoor-like environmental characteristics (e.g. low ventilation, poor air flow), and therefore may remain high risk for transmission.[88] for example, a team huddle, face-to-face wrestling action, or rugby scrum may reduce ventilation, and therefore respiratory aerosol and droplet particles may behave in a similar way to indoor interactions, thus increasing the sars-cov-2 transmission risk. however, to date, no sarscov-2 transmission has been reported during these activities. the outdoor transmission risk appears to be lower than first suggested, which has since been reflected in the modification of outdoor contact-tracing frameworks in sport.[7,88] whilst the sars-cov-2 transmission risk during outdoor team sports appears to have been downgraded, the data available only provides a preliminary insight into the overall risk, given the small sample sizes within the respective studies.[10,89,90] for example, in rugby league, eight infectious players inadvertently participated in matches with 100 other players.[10] in the 14 days following the matches, five players tested positive for sars-cov-2 via rt-qpcr, although these positive cases were most likely traced to social interactions, car sharing and wider community transmission and were not linked to in-match transmission. in outdoor evasion team sports, the overall purpose is to avoid the opposition. thus in some sports, this will mean that during the match close proximity interactions between players are rare and may only be fleeting in nature.[10] the greatest risk of sars-cov-2 transmission during outdoor sporting activities may be activities that are pre-match or proceed after that training activity, match or competition.[94] close proximity conversations, drink breaks, and pre-match, post-match or celebratory huddles may pose the greatest risk of sars-cov2 transmission, and should therefore be considered within sports risk mitigation strategies for outdoor sport activities. transmission risk during indoor sporting activities in addition to the aforementioned outdoor risk factors (e.g. ventilation of space, duration of close proximity between individuals), further considerations in indoor training settings should be given to the increased breathing frequency and particle expiration, particularly with moderate to vigorous aerobic activities.[91,92,95] activities associated with forced exhalation and deeper breathing have been shown to generate aerosol droplets that travel beyond 2 m,[96,97] extending the near-field transmission zone. the distance droplets and aerosols spread in the air can also be influenced by how an athlete moves within a space, given the risk of aerosol cloud formation within poorly ventilated spaces. mitigation strategies to compensate this include increasing physical distancing beyond 2 m, positioning equipment so that people face away from each other, the use of screens, and avoiding loud background music (which requires individuals to shout to be heard, further increasing the generation of aerosols and droplets). the regulations on the use of face coverings in indoor settings vary between countries, and use during exercise is an area of debate.[98-101] it may provide some discomfort and sweating can result in the mask becoming damp, although the risk to the mask wearer appears minimal. some indoor training activities may be more amenable for mask wearing (e.g. resistance training). furthermore, if physical distancing is inadvertently and temporarily breached whilst moving around indoors, face coverings may provide a further mitigation strategy to reduce the risk of sars-cov-2 transmission. this may also help mitigate inadvertent highrisk sars-cov-2 transmission situations (e.g. where people may congregate; entrances and exits, changing rooms and lockers, holding areas). physical distancing, the wearing of face coverings by staff and athletes where possible, and avoiding talking to others during or immediately after exercise can help reduce the sars-cov2 transmission risk during indoor sporting activities. fomite transmission should also be considered in relation to all surfaces, prioritising high-contact areas (e.g. drinking facilities, shared equipment, clothing). sweat does not appear to be a transmission mechanism for sars-cov-2,[102] thus surface contamination would be via fomites, caused by infectious respiratory aerosol and droplets. individual labelled drinks containers, clothing and towels, in addition to appropriate cleaning practices (e.g. paper towel, disinfectant spray and bins close to equipment, and clothing washed at a temperature of 60°c or above immediately after use) can help mitigate the sars-cov-2 transmission risk. transmission risk during aquatic activities the potential transmission risk of sars-cov-2 during aquatic activities is via transmission in water and expired aerosol and droplet transmission, linked to the proximity (and potential overcrowding) between individuals. the poor resistance of review sajsm vol. 33 no. 1 2021 8 enveloped viruses, such as sars-cov-2, to disinfected waters explains the limited transmissibility of this virus in water, regardless of the initial viral load.[103-105] furthermore, warmer water temperatures (i.e. >20-30° c) inactivate the virus quicker than lower temperatures (i.e., 4° c),[106] and previous studies have suggested that some natural spa, waters may already have an intrinsic antibacterial activity due to their chemical and physical properties, as well as due to their resident microflora.[107-109] the presence of viruses in the water of swimming pools is directly linked with contamination by bathers that could release traces of biological fluids, such as saliva or nasal mucus droplets, vomit or faeces.[110,111] pathogens and rna fragments can be detected in recreational waters (e.g. swimming pools) for several reasons, including inadequate compliance with disinfection procedures and technical failures. however, the primary risk of sars-cov-2 transmission between individuals remains via respiratory aerosols and droplets.[105,112] from a descriptive epidemiology perspective, the covid-19 pandemic affected people involved in very different occupational, recreational, or physical activities, but no outbreaks have been associated to swimming pools. physical distancing, masks and handwashing remain the key issues for prevention, and the practice of swimming itself would not represent a major risk compared to other activities and environments. both swimming pools and spa waters do not seem to constitute a specific risk, at least according to current epidemiological data.[105,112] the risk of sars-cov-2 transmission in water appears low, especially with the implementation of mitigation strategies. the sars-cov-2 transmission risk in aquatic sports appears linked to insufficient physical distancing whilst in swimming pools and spas, similar to other environments. maintaining physical distancing, avoiding overcrowding by scheduling systems, and the implementation of a one-way system to avoid inadvertent clustering of individuals should be a priority. similarly, optimising indoor ventilation and considering relative humidity and uv light (e.g. sunlight)[20,24] will collectively reduce the transmissibility of sars-cov-2 within swimming pools and similar environments. associated activities (e.g. changing rooms, travel) may pose the greatest sars-cov-2 transmission risk for aquatic sports. unique to aquatic sports is the need for changing room access (in comparison to soccer for example), therefore these sars-cov2 transmission risks should be considered, allowing similar risk mitigation strategies as other non-aquatic sports to be applied. associated sporting activities indoor meetings within sports, indoor individual and team meetings potentially pose a significant risk of sars-cov-2 transmission. advice regarding sars-cov-2 transmission in educational settings is applicable to team meetings in sporting contexts. this can be broadly categorised as advice relating to near-field transmission (i.e. transmission via larger respiratory aerosol droplets and person-to-person contact), and far-field transmission (i.e. transmission via fine aerosol droplets that become truly airborne). for any team meeting, it is advisable that individuals are seated at least 1 m (preferably 2 m) apart in an arrangement that avoids face-to-face exposure (i.e. participants seated behind each other rather than face-to-face). it is also advisable that face masks should be worn indoors, even when physical distancing is practised.[18] this is not primarily to protect the wearers (although some limited protection appears to be afforded by wearing low-efficiency medical and cloth masks),[113] but rather because there is evidence that wearing even low-quality masks reduces the emissions of sars-cov-2 virus-laden particles, both droplets and aerosols.[114,115] face masks block the shedding of ballistic droplets and larger aerosols and reduce the shedding of smaller respirable aerosols.[114,116] while it can be argued that face coverings are not always necessary indoors when good physical distancing is exercised and spaces are well ventilated,[117] given the wider implications associated with an athlete contracting covid-19 (e.g. weakened teams, abandoned matches and tours), the wearing of face masks is recommended when attending meetings held indoors. the airflow within a room is of paramount importance. it has been calculated that under steady-state conditions, the airborne viral load may reach as high as 1 248 rna copies/m3 in a poorly ventilated room, simply due to the breathing by a super-emitter (table 3).[118] in order to mitigate airborne (farfield) transmission, it is necessary to ensure the room space is well ventilated with outside air (i.e. >10 l/s per person) to ensure co2 levels are maintained below 1 000 ppm.[19,31] if room co2 levels exceed this threshold, strategies to increase the ventilation rate should be adopted. if the space is mechanically ventilated, the amount of outside air delivered should be maximised and the recirculated air minimised.[19] care should also be taken in buildings that employ centralised table 3. covid-19 r-numbers for a 1 400 m3 open-place office, occupied by 40 people for 8 hours each day, with a single pre/asymptomatic person present throughout the entire period [124,125] scenario quanta production rate (quanta/hr) ventilation rate (4 l/s per person) ventilation rate (10 l/s per person) ventilation rate (20 l/s per person) quiet desk work (low viral shedder) 0.3 0.25 0.13 0.07 quiet desk work (standard viral shedder) 1.0 0.84 0.42 0.24 talking sedentary 5.0 4.00 2.10 1.20 super-spreader (low) 20.0 14.00 7.60 4.40 super-spreader (high) 100.0 35.00 26.00 18.0 the values presented in columns 3-5 above are the predicted r-values (i.e. the expected number of secondary covid-19 infections arising from one infected person attending the office for 5 working days) for the specified ventilation rates. the quanta production rate associated with each activity scenario (column 1) is specified in column 2. review 9 sajsm vol. 33 no. 1 2021 heating, ventilation and air conditioning (hvac) systems. in such systems, to save energy during the winter months, up to about 80% of the extracted room air (return air) can be recirculated, with the result that aerosols containing the sarscov-2 virus may be widely re-distributed around the building.[19] if this is the case and it is not possible to convert the system to a full ‘fresh air’ system, then it may be necessary to retrofit ultraviolet (uvc) lamps, with a wavelength of 254 nm, into the return air ducts to disinfect the air and prevent recirculation of the virus.[19] whilst in team meetings, sars-cov-2 transmission risk can be worsened if the infector is talking loudly or shouting / singing. with an average sputum viral load, it has been estimated that speaking in a loud voice for one minute will generate >1 000 virion-containing aerosols.[119] therefore, theoretically a super-shedder, emitting a 100-fold higher viral load than average, could shed >100 000 virions in emitted droplets per minute of speaking.[120] applying findings from other settings, outbreaks have been reported in: nightclubs,[14] religious gatherings,[121,122] choirs and singing events,[123] and weddings. all these settings involve a high density of individuals within confined spaces for considerable periods of time, with most involving singing or talking in order to be heard above the background noise. while the short range (near-field) risk posed by ballistic droplets >100 μm can be mitigated by physical distancing, screens, and the use of face masks[18,126] during team meetings, the longer range (far-field) threat posed by smaller infectious aerosols must be countered either by ventilation which flushes airborne particles from the room space, or by air disinfection which biologically inactivates the virus.[20] the effectiveness of air purifiers can be determined via clean air delivery rate (cadr). the cadr indicates how many cubic meters of cleaned air the air purifier provides per hour and thus corresponds to the product of filter efficiency and volume flow rate that the unit circulates. at a cadr of 750 m³/h, the risk of infection per hour of time spent in a room with an infected person has been proposed to be reduced to 10%.[127] whilst the risk of infection is reduced, other mitigation strategies, such as ventilation and/or wearing masks, should also be implemented. air purifiers can be used between meetings, which typically provide three to six air changes per hour, although higher air change values (e.g. 6) are recommended during the covid-19 pandemic, to reduce the risk of infectious particles remaining within an environment.[127] further considerations should also be made when the air is cooler and drier, given that it has been shown that the sarscov-2 virus survives in aerosols for considerably longer,[27,28,128] and the viral half-life is >10 times longer during the winter and autumn months compared with the summer.[25] breaks and social interactions similar to many other occupational settings, individuals in sport may have coffee and lunch breaks throughout the day. these breaks can become high sars-cov-2 transmission risk situations, due to multiple people congregating in one location (e.g. queuing in the canteen), touching the same object or surface (e.g. coffee machine), and people wanting to socialise and speak to each other whilst being less vigilant. this can be worsened by the fact that masks must be removed to eat and drink. it is therefore important to carefully consider how social breaks are managed, so as not to inadvertently undermine infection control measures taken elsewhere. given the above, it is important to plan both spatially and temporally how social breaks are undertaken. this is particularly important when team meetings are held in shared facilities that might be occupied by other groups (e.g. sports centres). this also applies to the serving and eating of food, whereby buffet style meal serving will pose a greater risk of sars-cov-2 than table service, due to the risk of clustering and human-to-human interactions. where possible, people should be encouraged to physically distance themselves, eat and drink outdoors, and wear face masks up until the point where food or drink is consumed. it may also be advantageous to stagger meal timings to avoid large groups being within shared spaces without masks for a period of time. if consuming food and drink outdoors is not possible, then the seating and tables should be arranged to facilitate physical distancing in a well-ventilated space. travel and transportation sars-cov-2 transmission during travel poses a risk for elite sport, given that teams often travel in large groups both nationally and internationally. when planning travel arrangements, it is important to consider the mode of transport, required stops, and accommodation. in all situations, near-field risks can be mitigated via physically distancing, seating positions (e.g. seated behind, or side-byside, but not facing other travellers [129]), wearing face masks and minimising the unnecessary movement of individuals. during travel it is preferable that a distance of 2 m is maintained during the entire journey. this may also serve to reduce the density of people within a space [130] and also prohibit car sharing, due to the inability to maintain a physical distance of 2 m between individuals. when making travel plans, it is important to consider the prevalence of covid-19 in the destination population, as this will influence the likelihood of an interaction with an infectious native individual.[80] if the prevalence is high, extra precautions may be required, including bubbling the athletic group, as there will be a much greater chance of interactions occurring with hotel staff, officials and other support or service staff. this group may also benefit from routine screening protocols, which may include symptom monitoring, and daily sars-cov-2 diagnostic testing. travel on commercial public transport vehicles introduces a higher level of sars-cov-2 transmission risk exposure than travelling on a privately chartered vehicle, due to potential interactions with unmonitored individuals. chartered transport may not always be possible due to financial constraints. therefore, it is advisable to keep records of designated named seating plans. during the journey, movement around and conversation should be avoided with travellers.[129] the wearing of face masks will afford some protection to the wearer and prevent the dispersion of large respiratory droplets that could impact other travellers.[116] review sajsm vol. 33 no. 1 2021 10 limiting unnecessary travel breaks, and time spent at potential ‘infection hubs’ (e.g. shared spaces within airports, such as passport control and security screening, train stations, and motorway service stations) is advisable throughout a journey. this ensures that the group interacts with fewer external environments and individuals. journeys should be kept as short as possible in order to minimise overall risk to all involved. the far-field transmission risk is dictated largely by the ventilation characteristics of the particular passenger vehicle in question. in cars and older style buses and trains, it is possible to open the windows to promote ventilation. newer buses (coaches) and train carriages are typically hermetically sealed, and tend to overheat, especially in direct sunlight. as such they require mechanical cooling (air conditioning) and ventilation. this, however, consumes a considerable amount of energy,[131] with the result that manufacturers and operators tend to recirculate most of the air and minimise the amount of ‘fresh’ outdoor air that is supplied to the carriages.[132] co2 concentrations >1 800 ppm[132-134] and as high as 5 525 ppm[135] have been recorded on urban railway carriages during peak periods (co2 concentrations in well-ventilated spaces are generally <1 000 ppm).[19,31] this suggests that during periods of high occupancy, ventilation rates in passenger carriages are frequently inadequate to protect passengers from far-field sars-cov-2 transmission. given this, it is advisable for athletes to travel in a significantly reduced occupancy, which will also be a by-product of physical distancing measures. unlike trains and coaches, the air conditioning systems in aircraft cabins are generally fitted with high-efficiency particulate air (hepa) filters which are highly effective at removing viral particles from recirculated air,[11] keeping the supply clean and free of pathogens. they also allow a high air change rate to be maintained in the cabin space, which is much higher than would be normally found in buildings. few cases of covid-19 transmission have thus far been reported.[11,136] hepa filters make travelling in aircrafts less risky compared with other forms of transport with poorer ventilation properties. nevertheless, transmission events have occurred on long-haul flights [137] and therefore it is advisable to continue with good behavioural standards during flights.[11] one strategy that is often employed during periods of travel (including tournaments) to reduce the risk of infection is cohorting,[138] which in effect creates small ‘bubbles’, beyond which an infection cannot proceed.[129] in the context of travel, this might involve breaking the travelling party into smaller sub-groups (cohorts), so that each person interacts with only a few others.[129] the formation of ‘travel bubbles’ greatly reduces connectivity of the whole travel party, thus reducing the risk of sars-cov-2 exposure, and an individual from contracting covid-19, thus inhibiting the spread of the disease, and minimising the number of contacts identified who require isolation. this useful strategy may be expanded to camps and tournaments, where long stays are required in hotels and other types of accommodation. in this situation, enhanced protocols are required for the duration of the ‘travel bubble’ to prevent sars-cov-2 spreading within the group. this could also be extended to cover seating arrangements at meals, etc. additionally, the ‘travel bubble’ should limit the interaction with others from outside of this cohort (e.g. waiters), and have strict entry criteria should the cohort need to be expanded (e.g. new players or an additional service added). given the 14-day sars-cov-2 virus cycle, groups of athletes (and associated staff) should ensure that they follow a quarantine period for this duration of time, prior to becoming a ‘true bubble’, whereby physical distancing is not required, due to the cohort being confirmed as not infectious or infected with sars-cov-2. within this bubble, no interaction should take place with individuals from outside of this group (e.g. family or friends) to ensure that the virus cannot enter the group. transmission risk from spectators and media to sports staff and athletes risks from spectators, media and event staff is best understood by considering an event as a gathering comprising all present. where physical distancing is breached, outdoors or indoors, four risk factors have been identified. these are, the size of gathering, the density (at the macro-level, this is a measure for the whole gathering [number of people in a given space], at the micro level this can be interpreted as proximity or distance between individuals), the duration (both overall time at the gathering, or time spent in any particular interaction as part of the gathering), and the extent of circulation within the gathering.[130] this can be concurrently managed to mitigate each other in relation to community prevalence. in addition to the increased indoor transmission risk, an ‘indoor crowding effect’ has also been observed, where people naturally gather closer together.[130,139,140] sars-cov-2 diagnostic testing of media or other personnel prior to athlete interacts (e.g. interviews) can be also used to reduce the sars-cov-2 transmission risk. sars-cov-2 transmission risk for an event can be calculated based on community prevalence, event attendance, and the theoretical assumption that 50% of infected individuals are asymptomatic and presymptomatic. consequently, if community infection is 4 in 1 000, 2 are aware they are infectious (e.g. symptomatic) and therefore would not attend, for a gathering of 10 000 people, 20 infectious individuals may be unknowingly present within the crowd. this risk can by reduced via an increase in mass asymptomatic testing of the community. if the four identified mitigatable risks (size of gathering, density, duration, circulation) are applied to each fixture, the risk can be understood.[130] for example, a premiership soccer match is a large gathering, but with allocated seats, meaning the density is known, and the potential duration and circulation between the spectators and the group of athletes can be managed. at a ‘sunday league’ fixture, despite being a smaller gathering, the sars-cov-2 transmission risk to the group of athletes may be greater, given that spectators are typically not in allocated seats, can circulate freely, and have the potential to become within close proximity of athletes. some events (e.g. snooker, swimming) traditionally involve athletes being within closer proximity to spectators due to venue characteristics, which are also indoors. review 11 sajsm vol. 33 no. 1 2021 overall system to mitigate sars-cov-2 transmission within sport this review presents a summary of end-to-end sars-cov-2 transmission risk considerations for sport, providing an overview of transmission mechanisms and risks within specific scenarios and situations that are common for sport. sports should aim to identify and reduce the chance of infectious individuals entering the environment, and then quantify and mitigate higher risk situations to prevent the spread of covid-19 should an infectious individual enter the environment. the likelihood of this occurring increases during periods of high community covid-19 prevalence, given the significant association observed between new weekly cases of covid-19 in the community and professional rugby.[80] despite intensive monitoring and mitigation strategies, infectious individuals may still inadvertently enter the sporting environment. the identification and isolation of players and staff in elite sport should be undertaken with appropriate precision to prevent infected individuals remaining in the environment (e.g. resulting in potential virus transmission), and preventing low-risk contacts having to isolate, which potentially increases the risk of injury when returning. in addition, isolation may result in psychological strain, as well as causing wider disruption to competitions. therefore, sports are required to identify individuals who have potentially been exposed to the virus and are subsequently required to isolate. this can be a challenging if national government guidelines have not been developed for sports. in addition to covid-19’s specific protocols, the availability and sharing of video footage or human-to-human proximity data and subject interview, allows accurate close contact identification once a sars-cov-2 positive case is found. sportspecific contact tracing frameworks have been previously proposed (e.g. team sport risk exposure framework (tsref),[7] which has been used to identify increased risk sporting activities and to identify and isolate increased risk contacts during sporting activities.[10] the ts-ref has been applied to rugby league match activities (fig. 3a), which were consequently assigned a rating of ‘increased, medium or low risk’. this identified tackles and scrums as increased risk activities (fig. 3b). rule and player behaviour interventions were then developed and implemented to reduce the relative risk of rugby league match play from a sars-cov-2 transmission perspective (fig. 3c). as a consequence, rugby league in england temporarily removed fig. 3. (a) a list of rugby league game-specific actions, (b) application of team sport risk exposure framework (ts-ref)[7], (c) rugby league game-specific actions following potential risk-reduction interventions review sajsm vol. 33 no. 1 2021 12 scrums during the covid-19 pandemic to reduce the potential sars-cov-2 transmission risk. this also reduced the number of players that would have been required to isolate due to their involvement in increased risk activities, should an infectious player inadvertently participate in a match. the ts-ref has more recently been updated (the team sport risk exposure framework 2; ts-ref-2, fig. 4) to address the increased sars-cov-2 transmission risks indoors compared with outdoors. guidance on practically determining indoor and outdoor environments has been proposed, which considers if the space has a roof, the air velocity at low levels, the volume of the space and density of people in the area, environmental conditions and co2 concentration.[88] in addition to government contact tracing guidelines, the sportspecific frameworks may further support the identification of close contacts within a sporting environment, helping to reduce the risk of the infectious individual staying in the environment. conclusion this review provides a summary of end-to-end sars-cov-2 transmission risk factors for sport and an overview of transmission mechanisms to be considered by all stakeholders. the risk of sars-cov-2 transmission is greatest indoors, and primarily influenced by the ventilation of the environment and (close) proximity of the individuals. the sars-cov-2 transmission risk outdoors, via water and from fomites, appears less than initially thought. mitigation strategies include comprehensive end-to-end scenario planning of activities to optimise physical distancing, mask wearing and hygiene practice (for individuals, environment and equipment). the identification and removal of infectious individuals and their close contacts should be undertaken with appropriate precision to prevent further transmission. sports should aim to undertake activities outdoors where possible, given the lower sars-cov-2 transmission risk, in comparison to indoor environments. finally, the risk mitigation strategies presented may be applicable beyond the covid-19 pandemic to reduce the risk of virus transmission in sport. author contributions: bj, gp, mjc, spk, kas, cb conceptualised the review. bj, gp drafted the introduction, sections on sars-cov-2 transmission during outdoor sports activities and the overall risk mitigation section. fv, lb, vrp drafted the sections on sars-cov-2 transmission in water. te, era drafted the sections on sars-cov-2 fomite transmission and screening. rjc, cd, aj drafted the sections on sars-cov-2 transmission during indoor sports activities. gp, lh, jp drafted the sections on providing safe medical care. mw drafted the section on sars-cov-2 transmission with spectators and media. cb drafted the sections on sars-cov-2 transmission mechanisms and transmission risks during associated sporting activities. fig. 4. the team sport risk exposure framework 2; ts-ref-2 to identify increased risk contacts in sport [88] review 13 sajsm vol. 33 no. 1 2021 all authors critically reviewed, edited and approved the final manuscript. references 1. stokes ka, jones b, bennett m, et al. returning to play after prolonged training restrictions in professional collision sports. int j sports med 2020;41(13):895-911. 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[https://www.gov.uk/government/publications/review-what-isthe-evidence-for-the-importance-of-outdoor-transmission-andof-indoor-transmission-of-covid-19-2-april-2020] (accessed 27 february 2021) original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license the cycle ergometer test is not a reliable alternative to the countermovement jump in the assessment of power output kr peyper,1 mphil; b olivier,2 phd; a green,1 phd 1 department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa. 2 wits cricket research hub for science, medicine and rehabilitation, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: kr peyper (kpeyper@hotmail.com) rugby union is an intermittent, power-based contact sport involving high-impact collisions between opposing players, repeated highintensity bouts and continuous ballistic movements. [1] with condensed schedules, professional rugby union players and coaches are continually looking for ways to improve performance and prevent injury by improving fundamental physical qualities such as strength and power.[2] neuromuscular function is commonly used to measure the manifestation of fatigue in elite athletes.[2] fatigue can be described as an exercise-induced deterioration in performance [2], with studies showing that both acute [3] and chronic [4] workloads can affect neuromuscular function. mechanical power, a function of neuromuscular performance, is an integral component in the movements, collisions and success of rugby union athletes. the countermovement jump (cmj) and wattbike six-second peak power output (6ppo) tests are effective assessments in the measurement of mechanical power and changes in neuromuscular function, which can be measured with relative simplicity and at minimal additional fatigue to the athlete. the assessment of mechanical power helps to quantify the ability of the athlete to execute athletic movements.[5] the force plate has become the gold standard in the measurement of lower limb power due to its ability to measure different ground reaction forces and related metrics.[6] however, movements such as the cmj are ballistic in nature with a large eccentric component and emphasis on the stretch-shortening cycle. in the days following match play or training, the eccentric nature of the cmj becomes less favourable in athletes suffering from severe delayed onset of muscle soreness (doms) due to discomfort and a potential increase in the risk of injury. the wattbike cycle ergometer has recently been suggested as a non-load bearing method to evaluate lower limb power.[7,8] its predominantly concentric and less ballistic mechanism, could prove to be a replacement for the cmj as a measure of neuromuscular function and fatigue. commonly used cycle ergometer tests (cet) are the wingate thirty-second anaerobic test, wattbike thirty-second anaerobic power and wattbike 6ppo tests.[9] previous literature shows athletes produce maximum power within the first six seconds of a cet [7], making the wattbike 6ppo test an effective test of maximal power without the fatiguing effects of the thirty-second anaerobic tests .[9] moreover, positive relationships between the cmj and cet power outputs have been reported. [3,8] however, there is limited literature on the relationship between force plate cmj variables and cet outputs, and the benefits which such relationships may exhibit. the investigation on whether relationships exist between the f-v profiles of the athletes and the cet variables could also provide insight into whether the athletes are performing optimally. therefore, the aim of the study was to determine the concurrent validity of the cmj and wattbike cet power evaluations. methods participants healthy professional male rugby union players were invited to participate in the study. the study was approved by the institutional ethics committee (rec 01-55-2019). participants were injury-free at the time of testing and provided written informed consent prior to testing. testing procedures data collection was carried out at a professional rugby union training facility in johannesburg, south africa. participants background: rugby union is a physically demanding collision sport that requires optimal neuromuscular function for maximal power output, with mechanical power an integral component of performance. peak power (pp) and relative pp are parameters of neuromuscular function commonly assessed through the countermovement jump (cmj) as a measure of fatigue. the wattbike cycle ergometer test (cet) is a non-load bearing method of evaluating lower limb power. the cost-effective cet could therefore offer a viable alternative to the cmj. objectives: this study aimed to determine the concurrent validity of the cmj and cet. methods: thirty-eight professional rugby union players performed twelve cmjs on a force platform with four loads (bodyweight: bw-cmj; 20kg: 20-cmj; 40kg: 40-cmj and 60kg: 60-cmj) and a six second peak power (6ppo) cet assessment on a wattbike ergometer. results: cmj power outputs were [bw-cmj: pp 3101±648 w; 20-cmj: pp 2724±513 w; 40-cmj: pp 2490±496 w; 60-cmj: pp 2238±366 w] and cet [pp – 1310±161 w]. none of the cmj-pp values showed relationships with any cet power variables. large (r = 0.51-0.63; p = 0.000 – 0.001) relationships were found to be between relative cmj and relative cet power outputs. bland-altman plots, which were used to determine the level of agreement between the two assessments, showed the agreement between the tests was poor. conclusion: though positive relationships existed between relative cmj and relative cet power variables, analyses of the level of agreement in the bland-altman plots suggest that the two power assessment methods are not interchangeable measures of power. keywords: power, neuromuscular function, rugby union s afr j sports med 2022;34:1-5. doi: 10.17159/2078-516x/2022/v34i1a12869 mailto:kpeyper@hotmail.com http://dx.doi.org/10.17159/2078-516x/2022/v34i1a12869 https://orcid.org/0000-0002-0275-0070 https://orcid.org/0000-0001-9287-8301 https://orcid.org/0000-0002-7786-5454 original research sajsm vol. 34 no.1 2022 2 attended two different testing sessions in a randomised order on separate days during the off-season. test days were performed no more than three days apart, with the order of test days randomised. in both testing procedures, participants performed a standardised 10-minute investigator led warmup consisting of submaximal cycling, dynamic stretching and a series of submaximal countermovement jumps. countermovement jump (cmj) participants performed a modified cmj protocol consisting of three cmjs at each random added load of 0, 20, 40 and 60 kg respectively, with a rest time of three minutes between jumps. varying loads were utilised to determine where the strongest relationship may lie between the cmj and cet. a total of 12 cmjs were performed. an additional load was added to a barbell across the shoulders, while for the 0 kg jumps a plastic pipe (<1kg) was utilised. participants were instructed to use a self-selected depth in the eccentric phase of the cmj after which the concentric phase was performed as quickly as possible, keeping the legs fully extended in the air. any jumps which were inaccurately performed were reattempted after no more than five minutes of rest. all successful cmjs were recorded at 1000 hz using a force plate (bertec type 4060-05, bertec corporation, columbus, oh, usa). the highest attempt at peak force production of the three for each load was utilised for the final analysis. cycle ergometer test (cet) the six-second cet test procedure involved two six-second maximal sprints on a wattbike pro (wattbike ltd, nottingham, uk) with saddle and handlebars as well as air and magnetic resistance individually set in accordance with manufacturers’ guidelines.[8] the second test followed a rest of no more than five minutes and no verbal encouragement was given for either attempt. the best score of the two sprints was used for the final analysis. data analyses all jump analyses were based on the participants’ best cmj performance at each load. from these jumps, the following variables were obtained: peak force (fp), jump height (jh) and peak velocity (vp). fp was the highest force produced in the concentric phase of the cmj. power was calculated at each time point on the graph and peak power (pp) was the maximum value during the concentric phase. cmj mean power was calculated as the average instantaneous power over the concentric push-off phase of the jump. peak power, mean power (pm), relative pp and relative pm outputs from the cet were captured from the ergometers’ onboard computer. finally, theoretical maximal force (f0), theoretical maximal velocities (v0), theoretical peak power output (po) and gradient (sfv) were calculated for each participant’s f-v profile utilising the mean power data calculated from the force plate data. formulae vp (calculated utilising the trapezoid rule: ∫ 𝐺𝑅𝐹𝑧−𝑚𝑔 𝑚 𝑑𝑡 𝑡𝑓 𝑡𝑖 [14], where grf = ground reaction force (n), m = mass (kg), g = gravitational acceleration (m.s-2), ti = initiation time and tf = final time). [11] pp = (fp x vp). po = (calculated as f0.v0 4 ). [12] bland altman plots were used to describe the limits of agreement between relative pp and relative pm as measured in cmj and on the wattbike. the bias in the plots was determined as the average difference between the two assessments, while the upper and lower limits of agreement were set at 95%. the plots were utilised to evaluate bias between the two measurements and highlight that agreement is more a question of estimation, and not a form of hypothesis testing.[11] microsoft excel was used to compile the bland altman plots. statistical analysis data distribution was determined utilising a shapiro-wilk test. all data are presented as mean ± standard deviation. pearson’s and spearman’s correlations were used to determine the relationships between force plate metrics and power outputs on the wattbike. all data were analysed using statistical package for social science software (spss, ibm version 25.0. armonk, ny: ibm corp). qualitative descriptors were represented as trivial (<0.1), small (0.1-0.3), moderate (0.3-0.5), large (0.5-0.7), very large (0.7-0.9). results a sample of thirty-eight healthy professional male rugby union players from the greater johannesburg area (age: 20.2±1.6 years, stature: 183±7 cm, mass: 95.5±13.1 kg) participated in this study. the average cmj-fp values increased as the load was increased due to the added load and the acceleration of gravity. however, due to the added load and increased mass of the system cmj-vp, cmj-pp, and cmj-jh all decreased as the system became more difficult for the participants to move (table 1). the wattbike cet variables were calculated as cet-pp: 1310±161 w; cet-pm: 1160±155 w; relative cet-pp: 13.74±1.71 w.kg-1 and relative cet-pm: 12.16±1.62 w.kg-1. table 1. force, velocity, power, rate of force development and jump heights for weighted countermovement jumps bodyweight 20kg load 40kg load 60kg load peak force (n) 2389 ± 327 2537 ± 381 2665 ± 314 2863 ± 322 peak velocity (m.s-1) 2.87 ± 0.37 2.53 ± 0.20 2.30 ± 0.22 2.06 ± 0.15 peak power (w) 3101 ± 648 2724 ± 513 2490 ± 496 2238 ± 366 relative peak power (w.kg-1) 32.63 ± 6.80 relative mean power (w.kg-1) 18.20 ± 3.87 rate of force development (n.s-1) 5951 ± 3951 5286 ± 3620 3971 ± 2754 3533 ± 2700 jump height (m) 0.35 ± 0.06 0.29 ± 0.05 0.23 ± 0.05 0.21 ± 0.20 original research 3 sajsm vol. 34 no.1 2022 correlations were calculated between the outputs determined in the cmj and cet tests (table 2). large positive relationships (r = 0.52-0.66) were found between fp in all the cmjs and cet-pp and cet-pm. positive, moderate to large relationships (r = 0.34-0.68) were found between cmj-vp values and relative cet-pp and cet-pm values. the cmj-pp values exhibited no significant relationships with any of the cet variables; all correlation data are presented in table 2. large (r = 0.51-0.63) relationships were found between relative bodyweight cmj-pp and relative cet-pp and cet-pm variables, large (r = 0.51-0.63) relationships were also found between relative cmj-pm and relative cet-pp and cet-pm. additionally, only moderate relationships (r = 0.32-0.44) were found between cmj-jh in the loaded jumps and cet-pp and cet-pm (table 2). bland-altman plots were used to determine the level of agreement between relative peak power (figure 1) and relative mean power (figure 2) values in the cmj and cet. the limits of agreement (loa) in the relative pp plot were 8.8 w.kg-1 and 27.7 w.kg-1 for the lower and upper limits, respectively, with a bias of 18.3 w.kg-1. in relative peak power (figure 1), the majority of the points have a heteroscedastic appearance, indicating the increase in error was directly proportional to the increase in force. a single outlier and three points are noted outside of the upper loa. the loa in the relative pm plot were 0.3 w.kg-1, and 10.6 w.kg-1 for the lower and upper limits, respectively, with a bias of 5.5 w.kg-1. the pm plot exhibited a less uniform pattern, with two outliers and two values lying above the upper loa (figure 2). the cet power variables were compared to p0 (34.8±4.9 w.kg-1) and sfv (gradient: -11.7±4.3 n.s.m1.kg-1) calculated from the force-velocity profiles. only the cet relative peak power (r = 0.43) and relative mean power (r = 0.37) indicated moderate relationships with po (p < 0.05). neither cet peak (r = -0.05) or mean (r = -0.13) power exhibited any significant relationship with po or sfv (p > 0.05). discussion the purpose of this study was to examine the concurrent validity of the cmj and cet in professional rugby union players. numerous positive, moderate to large relationships were found between the cmj and cet variables. however, no significant relationships were found between cetpp, cet-pm, cmj-rfd or bodyweight cmj-jh and the cet power outputs. bland-altman plots showed little agreement between the relative cmj and relative cet power variables. rugby union is a game that requires multiple physical performance traits to initiate, evade and dominate various collision moments. measurement of force, velocity and power variables helps to quantify the ability of athletes to perform such tasks. owing to varying ranges and methods of jump loads used across studies [11,13], it was difficult to draw comparisons with the present study’s jump variables. the average fp results in table 2. correlations between countermovement jumps (cmj) and cycle ergometer test (cet) data cmj parameters cet pp pm relative pp relative pm fp bw 0.515** 0.554** -0.029 0.055 p-value 0.001 <0.001 fp 20kg 0.522** 0.604** -0.011 0.075 p-value <0.001 <0.001 fp 40kg 0.627** 0.655** -0.025 0.054 p-value <0.001 <0.001 fp 60kg # 0.562** 0.577** -0.101 -0.022 p-value <0.001 <0.001 vp bw # 0.184 0.067 0.680** 0.550** p-value <0.001 <0.001 vp 20kg 0.041 0.048 0.438** 0.405* p-value 0.006 0.01 vp 40kg # 0.122 0.098 0.339* 0.412* p-value 0.04 0.01 vp 60kg # 0.090 0.082 0.535** 0.563** p-value 0.001 <0.001 pp bw # 0.168 0.135 0.251 0.206 pp 20kg 0.089 0.090 0.138 0.188 pp 40kg 0.070 0.045 0.172 0.251 pp 60kg 0.100 0.072 0.200 0.264 relative pp bw # 0.194 0.136 0.631** 0.507** p-value <0.001 0.001 relative pm bw 0.196 0.138 0.634** 0.510** p-value <0.001 0.001 rfd bw # -0.203 -0.243 -0.096 -0.055 rfd 20kg # -0.185 -0.174 0.120 0.150 rfd 40kg # -0.236 -0.131 0.142 0.220 rfd 60kg # -0.044 -0.052 0.120 0.170 jh bw 0.284 0.297 0.008 0.014 jh 20kg 0.346* 0.324* -0.021 0.080 p-value 0.03 0.05 jh 40kg # 0.385* 0.435** -0.092 0.012 p-value 0.02 0.006 jh 60kg # 0.340* 0.320 -0.006 0.057 p-value 0.04 sfv 0.045 -0.048 -0.114 -0.212 po # -0.053 -0.127 0.431** 0.370* p-value 0.007 0.02 * indicates p < 0.05; ** indicates p<0.01; # indicates spearman’s ranked correlations. bw, bodyweight; fp, peak force; vp, peak velocity; pp, peak power, pm, mean power; rfd, rate of force development; jh, jump height; sfv, gradient; po, theoretical peak power output. original research sajsm vol. 34 no.1 2022 4 the bodyweight cmjs were lower than those found in previous literature on elite rugby union players.[14] the average vp results were similar to results previously obtained in studies conducted on rugby players.[5,15] however, the average pp results were not supported by previous literature on professional rugby union players.[14,16] these findings could be due to the participants in the present study’s lower fp production than in the previously mentioned research, which could have been caused by a number of factors. the younger average age in the current sample could indicate that the athletes had not reached full maturity in strength training. previous research indicated similar findings of lower fp output in young rugby union professionals. [17] the training methods and game plan utilised by the athletes and organisations in question may differ from other athletes and organisations. the average relative pp results of the present study also indicated considerably lower results than previous literature [15], however, this was expected due to the lower fp production of the athletes in the study. when comparing the peak power and relative power outputs, it is important to note that relative power could provide a more accurate comparison of performance, especially in rugby union where performance variables and anthropometry differ greatly between positions.[1] jump height is a standard measurement in most power-based sports, with some sports placing an emphasis on jump height when selecting players. the average bodyweight cmj-jh in the present study exhibited similar results to those found in a previous study on rugby league players.[16] however, measuring cmj-jh alone may not provide sufficient data when assessing performance in athletes as previous research found that power and rate of force development (rfd) were more related to sport-specific movements and could provide a more accurate indication of the athletes’ ability to produce powerful sportspecific movements.[18] the rfd results, as with the pp results, in the present study were, however, also found to be considerably lower than those in previous research on professional rugby union players.[14] as previously mentioned, the lower force production by the athletes in the present study could have affected jump variables such as rfd. force-velocity profiles were established using cmj data in order to determine whether any relationship existed between cet power variables and the f-v profiles. the absence of any relationship between the theoretical peak power in f-v profiles and cet power outputs suggested that the participants in the study may not have exhibited optimised f-v profiles. these findings are in line with the previous argument that the lower force production of the athletes in this study could affect the jump variables, and subsequently the f-v profiles. therefore, further investigation is needed on cet and f-v profiles. the wattbike cycle ergometer is amongst the industry’s leading devices for assessment of lowerlimb power. the results for the present study in the cets were supported by previous literature on professional rugby union players.[19] the cmj and cet differ in mechanism, with the cmj being more ballistic and bilateral in nature than the cet. this difference in mechanism is indicated by the vast difference in peakand mean power output figures between the assesments. however, the cmj and cet are both accurate tests of lower limb power output and it fig. 1. bland-altman plot indicating the heteroscedastic distribution of data points between the limits of agreement between relative peak power values in the countermovement jump (cmj) and cycle ergometer test (cet) data in 38 professional rugby union players. fig. 2. bland-altman plot indicating the equal scattered distribution of data points above and below the bias, between relative mean power values in the countermovement jump (cmj) and cycle ergometer test (cet) data in 38 professional rugby union players. original research 5 sajsm vol. 34 no.1 2022 was therefore important to determine whether any relationship existed between the two assessment methods. the cmj is the most frequently used measurement of neuromuscular function.[4,13] previous literature on rugby union players [8] and australian rules football players[3] have all reported positive relationships between cmj and cet power outputs. though no relationship existed between cmj and cet peak and mean power outputs in the present study, the large relationships found between the relative power outputs show that the cet may be a suitable alternative to the cmj when assessing power outputs. however, the cet is limited by the number of variables it can assess. while the cmj can assess eccentric and concentric phases of motion and components of the stretch-shortening cycle, the cet can only assess the concentric phase. bland-altman plots were therefore used to determine the level of agreement between the relative pp outputs and relative pm outputs. though the cet presents a more viable and cost-effective alternative to the force plate cmj, the insufficient agreement shown between the two assessment methods indicates that the two assessments are not interchangeable as measures of lower limb power. specifically, the large biases and wide limits of agreement indicate that, although the assessments can both be utilised to measure lower limb power, they should not be used interchangeably. practical applications the cmj and cet procedures utilised in the present study are both independent accurate measures of muscular power development as they assess lower limb power utilising different mechanisms. the cet could be considered a viable, non-interchangeable alternative to the force plate cmj. therefore, coaches and trainers are advised to adhere to single modes of muscular power testing. conclusion the present study sought to compare the cmj variables and cet power outputs in professional rugby union players. only the relative cet power metrics shared large relationships with relative cmj metrics. however, the lack of agreement between the two tests indicates that the wattbike 6ppo test should not be used as an interchangeable alternative power assessment. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: kp and ag project conception, data collection, data analysis, manuscript draft and review. bo data analysis, manuscript draft and review. references 1. twist c, worsfold p (eds). the science of rugby. abingdon: routledge, 2015. 2. cunniffe b, proctor w, baker js, et al. an evaluation of the physical demands of elite rugby union using global positioning system tracking software. j strength cond res 2009; 23(4): 11951203. [doi: 10.1519/jsc.0b013e3181a3928b][pmid: 19528840] 3. wehbe g, gabbett tj, dwyer d, et al. monitoring neuromuscular fatigue in team-sport athletes using a cycle ergometer test. int j sports physiol perform 2015; 10(3): 292-297. [doi: 10.1123/ijspp.2014-0217][pmid: 25115142] 4. roe g, darrall-jones j, till k, et al. between-days reliability and sensitivity of common fatigue measures in rugby players. int j sports physiol perform 2016; 11(5): 581-586. [doi: 10.1123/ijspp.2015-0413][pmid: 26390328] 5. gathercole rj, sporer bc, stellingwerff t, et al. comparison of the capacity of different jump and sprint field tests to detect neuromuscular fatigue. j strength cond res 2015; 29(9): 25222531. [doi: 10.1519/jsc.0000000000000912][pmid: 26308829] 6. beckham g, suchomel t, mizuguchi s. force plate use in performance monitoring and sport science testing. new studies in athletics 2014; 29(3): 25-37. 7. cox p. wattbike training tests. retrieved from https://support.wattbike.com/hc/en-gb/articles/360013621359-6second-test-recommended-resistance-settings-. accessed may 10, 2019. 8. roe g, darrall-jones j, till k, et al. to jump or cycle? monitoring neuromuscular function in rugby union players. int j sports physiol perform 2017; 12(5): 690-696. [doi: 10.1123/ijspp.20160273][ pmid: 27736241] 9. herbert p, sculthorpe n, baker js, et al. validation of a six second cycle test for the determination of peak power output. res sports med 2015; 23(2): 115-125. [doi: 10.1080/15438627.2015.1005294][ pmid: 25720917] 10. altman dg, bland jm. interaction revisited: the difference between two estimates. bmj 2003; 326(7382): 219. [doi: 10.1136/bmj.326.7382.219][ pmid: 12543843] 11. lombard w, reid s, pearson k, et al. reliability of metrics associated with a counter-movement jump performed on a force plate. meas phys educ exerc sci 2017; 21(4): 235-243. [doi: 10.1080/1091367x.2017.1354215] 12. morin jb, samozino p. interpreting power-force-velocity profiles for individualized and specific training. int j sports physiol perf 2016; 11(2): 267-272. [doi: 10.1123/ijspp.2015-0638][pmid: 26694658] 13. jiménez-reyes p, samozino p, cuadrado-peñafiel v, et al. effect of countermovement on power-force-velocity profile. eur j appl physiol 2014; 114(11): 2281-2288. [doi: 10.1007/s00421-014-29471][pmid: 25048073] 14. jones tw, keane k, smith a, et al. which anthropometric and lower body power variables are predictive of professional and amateur playing status in male rugby union players? int j sports sci coach 2019; 14(1): 82-90. [doi: 10.1177/1747954118805956] 15. weakley j, mann b, banyard h, et al. velocity-based training: from theory to application. strength cond j 2021; 43(2): 31-49. [doi: 10.1519/ssc.0000000000000560] 16. mcmahon jj, suchomel tj, lake jp, et al. relationship between reactive strength index variants in rugby league players. j strength cond res 2021; 35(1): 280-285. [doi: 10.1519/jsc.0000000000002462][pmid: 29401201] 17. gowtage wj, moody ja, byrne pj. complex training with minimal recovery intervals and their effect on cmj performance in professional male rugby union players. arc j res sports med 2020; 5(1):1-8. [https://www.arcjournals.org/pdfs/ajrsm/v5i1/1.pdf] 18. maffiuletti na, aagaard p, blazevich aj, et al. rate of force development: physiological and methodological considerations. eur j app physiol 2016; 116(6):1091-1116. [doi: 10.1007/s00421016-3346-6][ pmid: 26941023] 19. grainger a, ripley nj. ,. comparison between a 6 second and 30 second cycle ergometer test for peak power in elite rugby union players. j australian strength cond 2018; 26(3): 27-30. sportsmed_june04 12 sports medicine vol 16 no.2 2004 introduction strenuous endurance exercise and long-term endurance training are associated with muscle adaptations and damage, with reports of ultrastructural and morphological changes2,9,15 as well as a systemic inflammatory response.39 research has reported mobilization and activation of neutrophils,4,19 heightened leucocyte turnover,4 and a complex pattern of proand anti-inflammatory cytokine release related to muscle or tissue damage.27,41 whether strenuous endurance exercise affects the airway and systemic compartments similarly, and the possibility that it may cause adpatations or damage at the airway level, are issues that require further research. it has been shown that strenuous endurance exercise affects the airways by increasing the incidence of upper respiratory tract infections (urtis) related to bacterial or viral infections26,29 and respiratory symptoms such as exerciseinduced bronchoconstriction (eib)1,16 or airway hyperresponsiveness (ahr).22,33 whilst immunosuppression has been related to the increase in urtis,21 studies on airway cells and inflammatory markers in endurance athletes have suggested a possible association between airway inflammatory cells and exercise-induced respiratory symptoms.5 recently, it was found that common viral and bacterial agents as well as allergy/asthma were not responsible for upper respiratory tract symptoms (urts) reported 2 10 days after an ultramarathon race.37 the results suggested that the urts symptoms may be due to mucosal inflammation in the upper respiratory tract (urt), although airway inflammatory cells and markers were not measured. eosinophils have been recognised as urt pro-inflammatory cells with a considerable tissue-injuring potential,42 and have been shown to mediate damage to respiratory epithelium as well as shedding of bronchial epithelium leading to tissue damage.17 eosinophil cationic protein (ecp) is an eosinophil granule-derived protein and serum ecp is regarded as a highly sensitive marker of eosinophil activation in the original research article non-allergic activation of eosinophils after strenuous endurance exercise a j mckune (mmedsci)1 l l smith (phd)1 s j semple (mtech)1 a a wadee (phd)2 1department of sport and physical rehabilitation sciences, tshwane university of technology, pretoria 2department of immunology, university of the witwatersrand and the national health laboratory service, johannesburg correspondence: a j mckune private bag x680 pretoria 0001 tel: 012-318 4442 fax: 012-318 5801 e-mail: mckunea@techpta.ac.za abstract objective. to determine the effect of prolonged endurance exercise on the serum concentrations of eosinophil cationic protein (ecp), immunoglobulin e (ige) and upper respiratory tract symptoms (urts). design. in 11 healthy, experienced volunteers (6 males, 5 females, age 43 ± 9.8 years) the serum concentrations of ecp and ige were measured, 24 hours prior to projected finishing time, immediately post exercise (ipe), and 3 h, 24 h, and 72 h after an ultramarathon (90 km). self-reported urts were also recorded for 14 days after the race. ecp was measured using radioimmunoassay and ige using the alastat microplate total ige kit. the after-exercise values were corrected for plasma volume changes, which were calculated from haematocrit and haemoglobin values. serum concentrations of ecp and ige were analysed using an analysis of variance (anova) comparing values with before-exercise levels. level of significance was set at p ≤ 0.05. results. ecp was significantly elevated at 72 hours (+52%), whilst ige was not significantly altered after the ultramarathon. there were no reported urts for the 14 days after the race. conclusion. the eosinophil is a pro-inflammatory leukocyte involved in bronchial hyperreactivity and allergic inflammation of the airways. ige is associated with allergic diseases such as asthma and rhinitis. serum ecp is a sensitive marker of eosinophil activation. the result provides evidence for the non-allergic activation of blood eosinophils during prolonged endurance exercise. whether this indicates exercise or environmentally induced airway inflammation, or a role for ecp in muscle /tissue repair, are hypotheses that require additional research. sports medicine vol 16 no.2 2004 13 urt.43 ecp plays an important role in the pathogenesis of urt allergic inflammation11 and asthma, where it is released in response to allergen-immunoglobulin e (ige) crosslinking.14 recently, it was reported that a dietary deficiency of antioxidant vitamins may play a role in increasing the severity of asthma.24 bowler amd crapo6 suggested that augmentation of existing antioxidant defences with catalytic antioxidants might be useful in attenuating respiratory disorders through counteracting the effects of inflammatory cells such as airway eosinophils. similarily, it has been reported that antioxidant supplementation may reduce the incidence of urti after ultramarathon running.30 however, bowler and crapo6 concluded that the use of antioxidants in the treatment of airway reactions requires further study. recently, it was shown that the use of airway anti-inflammatory medication reduced the self-reported incidence of urts in ultramarathon runners.36 only two previous studies have reported that eosinophils may be activated by non-allergic mechanisms in healthy subjects. both prolonged endurance exercise11 and short-term maximal exercise12 were shown to increase serum ecp in healthy subjects. there is therefore, limited data on the response of eosinophils to a physiological challenge such as endurance exercise, and the possibility that these cells may be associated with the urts reported after endurance exercise in non-allergic/asthmatic individuals is yet to be explored. the aim of the study was therefore to monitor eosinophil activation by measuring serum ecp, a possible allergic involvement through measuring alterations in serum ige, and the association that alterations in these serum proteins may have with urts after an ultramarathon. methods subjects eleven experienced runners (6 males, 5 females) from local running clubs and who had entered the 2002, 90 km comrades ultramarathon, volunteered to participate in this study. exclusion criteria subjects who reported that they smoked or suffered from asthma, allergic rhinitis, respiratory disease or had an urti in the week leading up to the ultramarathon were excluded. the protocol was approved by the tshwane institute of technology ethics committee, and informed consent was obtained from each subject. medication and nutritional supplements subjects were asked to abstain from the use of anti-inflammatory and anti-histamine medication. the use of multivitamins and anti-oxidants was not controlled. however, the subjects recorded their dietary and supplement intake for 2 weeks before and 2 weeks after the comrades to help control for the possible effect of multivitamin and anti-oxidant intake on results. study design the subjects reported to the exercise testing laboratory 2 weeks before the race where they completed questionnaires relating to their health history, training schedule (distance run in the past 6 months), and ultramarathon experience. following completion of the questionnaires, body composition and cardiorespiratory fitness were determined. body composition height and weight were recorded using a calibrated medical height gauge and balance scale (detecto, webb city, usa). a harpenden skinfold caliper was used for skinfold measurements (7 sites) to assess body composition using the drinkwater-ross method.34 maximal oxygen uptake and heart rate subjects were instructed to abstain from high-intensity or long-duration training sessions the day prior to being tested. in addition they were instructed to eat a light meal three hours prior to the vo2max. testing. the test was performed on a quinton 90 treadmill (quinton instrument co., seattle, washington). continuous respiratory measurements were recorded by means of the medgraphics cardio2 combined vo2 /ecg exercise system (medical graphics corporation, chicago, illinois). heart rate response was monitored using a polar heart rate monitor. the test began at 8 km/h on a 3% incline, for 5 minutes. thereafter, speed and gradient were increased at 1 km/h and 1% respectively every minute. from 12 km/h, only the gradient was increased by 1% per minute until exhaustion.23 standard criteria were used to ensure attainment of vo2max. 32 ultramarathon testing upper respiratory tract symptoms twenty-four hours prior to the projected finishing time the runners completed a questionnaire on their state of health during the 2 weeks leading up to the race. for 2 weeks after completion of the race the subjects completed a daily questionnaire regarding the severity and duration of urts. the questionnaire included a scale which assessed the severity and duration of self-reported urts such as a running nose, sneezing, sore throat, and cough.29 blood draws venous blood samples (15 ml) were collected 24 hours prior to projected finishing time, and then within 10 minutes immediately post exercise (ipe), and 3 h, 24 h, and 72 h after the ultramarathon. five millilitres of blood were collected in glass vacutainer tubes containing the anticoagulant, tripotassium ethylenediaminetetraacetic acid (k3-edta) and were used to determine full blood counts. ten millilitres were collected in serum separator tubes which remained at room temperature for 30 minutes. these tubes were then centrifuged for 10 minutes and the serum was divided into 0.5 ml aliquots and stored at –80°c until analysis. haematological adjustments full blood counts were performed on k3-edta-treated specimens using standard haematological procedures on an automated stks model (coulter electronics inc., hialeah, florida, usa). plasma volume changes were determined from preand post-race haemoglobin and haematocrit values using the method of dill and costill.10 14 sports medicine vol 16 no.2 2004 determination of ecp and ige serum ecp concentrations were determined using a radioimmunoassay technique (ecp-ria, pharmacia, stockholm, sweden) as described by peterson et al.31 serum ecp was considered normal within the range of 2 15 µg/l. the total serum ige (normal range, 22 86 ku/i) was determined with the use of the alastat microplate total ige kit (diagnostic products, usa) according to the manufacturer's instructions and by comparison with a known range of standard ige concentrations. high and low control samples were run for both assays, and all samples were analysed in triplicate. to avoid inter-assay variability, all samples from each subject were assayed on the same microtitre plate. statistical analysis results are expressed as means ± se. data were analysed using commercial software (sas institute, cary, nc) using an analysis of variance (anova), contrasting variables to baseline values. tukey’s post hoc tests were use to determine significant differences attributed to time. the level of significance was set at p < 0.05. results subjects demographic data on the runners are shown in table i. the subjects in the study were experienced ultramarathon runners having completed an average of 4 ultramarathons. the average distance covered in training in preparation for the ultramarathon was 1 377.3 km (january june). the average time taken to complete the race (9.45 h ± 1.1) indicates that the athletes were not in the elite category. the cut-off time for the race is 11 hours, with the top 10 runners usually completing the 90 km under 6 hours. there were no reports of urts in the 2 weeks prior to or after the ultramarathon. the dietary and supplement records did not reveal excessive intake of multivitamins or anti-oxidants. serological parameters the before and after-race levels of ecp (normal < 15 ug/l) and ige (normal range 22 85 ku/l) were within clinically normal reference ranges. all after-race exercise concentrations of ecp and ige were corrected for exercise-induced plasma volume changes before statistical analysis. eosinophil cationic protein level began rising immediately after the ultramarathon. fig. 1 shows that the ecp level was significantly increased (+52%) at 72 h (p = 0.03) compared with the before-exercise level. there was no significant alteration in ige concentration after the ultramarathon (fig. 2). discussion strenuous endurance exercise causes significant stress to the respiratory system, from the associated hyperventilation, as well as increased airway exposure to contaminants of inhaled air3,7,25,40 such as allergens or pollutants.18 urts have been linked with bacterial or viral infection during an ‘openwindow period’, 3 72 hours after exercise where an individual is susceptible due to exercise-induced immunosuppression.21 recently, it was hypothesised that urts after an ultramarathon may not be due to bacterial or viral infection or allergy,37 with the results suggesting that mucosal urt inflammation may be the source of urts. the present study investigated the effects of an ultramarathon on immune parameters, which could be associated with postexercise urts. table i. subject characteristics parameter mean (± sd) age (years) 43 (± 10) height (cm) 170 (± 10) weight (kg) 64 (± 13) body fat (%( 14 (± 3) vo2 max (ml/kg/min) 57.5 (± 6) hrmax (beats/min) 172 (± 15) weekly training distance (km/wk) 58 (± 17) race time (hours) 9.45 (± 1.1) 24 pre ipe 3 post 24 post 72 post time (hour) 1 2 3 4 5 6 e c p ( u g /l) 24 pre ipe 3 post 24 post 72 post time (hour) 21 26 31 36 41 46 51 ig e ( k u /i ) fig. 1. alterations in serum eosinophil cationic protein (µg/l) of 6 male and 5 female subjects following an ultramarathon. signifies p < 0.05 compared with before race levels. fig. 2. alterations in serum immunoglobulin e (ku/i) of 6 male and 5 female subjects following an ultramarathon. sports medicine vol 16 no.2 2004 15 eosinophil cationic protein was significantly increased 72 hours after the ultramarathon (fig. 1) whilst ige was not significantly altered (fig. 2). these data suggest a non-allergic activation of blood eosinophils after strenuous endurance exercise. recently, a similar elevation in serum ecp was reported to provide evidence for a moderate generation of bronchial hyperreactivity in healthy individuals after prolonged endurance exercise.11 a subclinical, non-allergic inflammation associated with eosinophil activation within the airways was suggested to be responsible for the increase in bronchial reactivity.11 it was proposed that intense prolonged mouth breathing of cold, dry air during exercise might have been responsible for increased respiratory water loss and subsequent osmotic challenge to the bronchial epithelium. damaged epithelial cells might then have attracted circulating eosinophils to the airway mucosa via the release of the cytokines interleukin-5 (il-5) and tumour necrosis factor-α. these eosinophils subsequently degranulated with the release of ecp, which caused further damage and inflammation in the respiratory epithelium.11 this is a possible explanation for the raised serum ecp in the present study. although bronchial hyperactivity was not measured and there were no reported clinical urts for the 2 weeks after the ultramarathon, the raised serum ecp levels in both studies suggest the possibility that an acute bout of strenuous endurance exercise may cause weak mucosal urt inflammation. this inflammation may be similar in nature to that found in a process called ‘minimal persistent inflammation’ (mpi) that has been demonstrated in both mite-induced and pollen-induced rhinitis8 and asymptomatic allergic subjects.28 although the urts questionnaire has been used successfully in the past to identify urts30 it is possible that a more sensitive questionnaire is required to identify self-reported symptoms/manifestations of minimal airway inflammation. the questionnaire used was biased towards urti symptoms and therefore a future study should look at validating a questionnaire that is sensitive to symptoms of airway inflammation. an additional explanation for the lack of reported urts is the small sample size. a larger sample size may have increased the probability of more subjects with urts. the authors therefore do not rule out the possibility of urts related to the presence of ecp in the present study. whether frequent episodes of such non-allergic ecp peaks create a higher risk in healthy individuals for developing exerciseinduced and allergic asthma/rhinitis over time, or increased after-exercise reporting of urti-like symptoms, are questions that remain unanswered. short maximal exercise has also been shown to cause a non-allergic activation of eosinophils in healthy individuals. plasma ecp was shown to be elevated immediately after a graded maximal bicycle exercise test.12 two possible explanations for eosinophil activation were provided which are related to exercise-induced muscle/tissue damage. firstly, that ecp is usually released by eosinophils to deal with nonphagocytosable opsonised micro-organisms (e.g. parasites).20 it was speculated that during strenuous exercise non-phagocytosable muscle/tissue fragments are liberated accounting, in analogy to the defence against parasites, for the eosinophil activation and ecp release. the second explanation was that ecp has been shown to participate in muscle/tissue repair processes by modifying the production of glycosaminoglycans by human fibroblasts.35 these two explanations are feasible for the present study as strenuous endurance exercise has been reported to cause muscle / tissue damage2,9,15,41 that requires removal and repair. the acute phase response (apr) to muscle/tissue damage, specifically the activation of complement components c3, c4 and c5 fragments, may be a possible mechanism for activating eosinophils.13 submitted data from the present study have shown that the same ultramarathon caused an apr and an increase in complement,38 and this may have played a role in the non-allergic activation of eosinophils. conclusions the finding that ecp was elevated after the ultramarathon leads to various hypotheses that require testing. firstly, that non-allergic eosinophil activation is maladaptive and that frequent episodes of subclinical exercise-induced ecp peaks in healthy individuals might result in mpi and the development of exercise-induced or allergic asthma/rhinitis. secondly, that non-allergic eosinophil activation represents a normal physiological adaptive response of the immune system to the presence of non-phagocytosable muscle/tissue fragments and that eosinophils are activated to assist with removal and repair. thirdly, that the urts reported after exercise by individuals may not be the result of infection but rather due to mucosal urt inflammation induced by activated inflammatory cells in the urt. further studies are therefore necessary to test these hypotheses and at the same time aim to determine, in terms of inflammatory processes in the urt: (i) the exercise dose-response; (ii) the role of environmental factors in determining different airway cell patterns; (iii) the timecourse and features of training-induced adaptations, and (iv) long-term effects of exercise training, and their possible impact on respiratory health.5 acknowledgements this research was supported by grants from the faculty of health sciences, tshwane university of technology and the national research foundation, thuthuka programme, south africa. references 1. anderson sd, daviskas e. the mechanism of exercise-induced asthma is... j allergy 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287-91. 28. passalacqua g, canonica gw. impact of rhinitis on airway inflammation: biological and therapeutic implications. respiratory research 2001; 2: 320-3. 29. peters em, bateman ed. ultramarathon running and upper respiratory tract infections: an epidemiological study. s afr med j 1983; 64: 582-4. 30. peters em, goetzsche jm, grobbelaar b, noakes td. vitamin c supplementation reduces the incidence of postrace symptoms of upper-respiratory-tract infection in ultamarathon runners. am j clin nutr 1993; 57: 170-4. 31. peterson cg, enander i, nystrand j, anderson as, nilsson l, venge p. radioimmunoassay of human eosinophil cationic protein (ecp) by an improved method. establishment of normal levels in serum and turnover in vivo. clin exp allergy 1991; 21: 561-7. 32. powers sk, howley et. exercise physiology: theory and application to fitness and performance. new york: mcgraw-hill higher education, 2001. 33. provost-craig ma, arbour ks, sestili dc, chabalko jj, ekinci e. the incidence of exercise-induced bronchospasm in competitive figure skaters. j asthma 1996; 33: 67-71. 34. ross wd, wilson nc. growth and development. a stratagem for propotional growth assessment. acta paediatr belg 1974; 24: 169-82. 35. särnstrand b, westergren-thorsson g, hernäs j, peterson cgb, venge p, malmström a. eosinophil cationic protein and transforming growth factor-a stimulates synthesis of hyaluronan and proteoglycan in human fibroblast cultures. in: cordier lf, ed. fifth international colloquium on pulmonary fibrosis. lyon, france: american thoracic society, 1988: 3988. 36. schwellnus mp, keissig m, derman w, noakes td. fusafungine reduces symptoms of upper respiratory tract infections (urti) in runners after a 56 km race. med sci sports exerc 1997; 29: s296. 37. schwellnus mp, tune mj, derman ew, noakes td. post ultra-marathon upper respiratory tract symptoms are not caused by an infection. med sci sports exerc 2002; 34: s168. 38. semple sj, smith ll, mckune aj, neveling n, wadee a. alterations in acute-phase reactants (crp, rheumatoid factor, complement, factor b, and immune complexes) following an ultramarathon. south african journal of sports medicine 2004; 16: 17-21 (this issue). 39. shek pn, shephard rj. physical exercise as a human model of limited inflammatory response. can j physiol pharmacol 1998; 76: 589-97. 40. shephard rj, rhind s, shek pn. exercise and the immune system. sports med 1994; 18: 340-69. 41. smith ll. overtraining, excessive exercise, and altered immunity: is this a t helper-1 versus t helper-2 lymphocyte response? sports med 2003; 33: 347-64. 42. venge p, hakansson l. current understanding of the role of the eosinophil granulocyte in asthma. clin exp allergy 1991; 21: suppl 3, 31-7. 43. wardlaw aj. eosinophils in the 1990's: new perspectives on their role in health and disease. postgrad med j 1994; 70: 536-52. original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license headers and concussions in elite female and male football: a pilot study s den hollander,1 phd; v gouttebarge,1-5 phd 1 football players worldwide (fifpro), hoofddorp, the netherlands 2 amsterdam umc location university of amsterdam, department of orthopedic surgery and sports medicine, meibergdreef 9, amsterdam, the netherlands 3 amsterdam collaboration on health & safety in sports (achss), ioc research center, amsterdam, the netherlands 4 section sports medicine, university of pretoria, pretoria, south africa 5amsterdam movement sciences, musculoskeletal health, sports, amsterdam, the netherlands corresponding author: v gouttebarge (v.gouttebarge@amsterdamumc.nl) research has indicated a potential causal link between repetitive head impacts and chronic traumatic encephalopathy, a neurodegenerative disease. [1] as such, concerns over the risk of cognitive decline and neurodegenerative diseases associated with heading in professional footballers has resulted in several attempts to limit the exposure to heading in training. [2, 3] however, in elite men’s and women’s football, not enough is known regarding the exposure to headers or their effect on cognitive function. this information is crucial to allow stakeholders to make informed decisions and intervene, where necessary, to improve players’ safety. research across five top men’s european leagues has found that defenders made approximately six headers per match, and midfielders and forwards four per match. [4] in elite women’s football, across positions, players make an average of four headers per player per match. [5, 6] in both women’s and men’s elite football, little is known about the exposure to headers in training. [7] this lack of data needs to be addressed, while the exposure to headers should be objectively quantified through, for example, video analysis, as subjective self-reported measures have been shown to be invalid. [8, 9] along with quantifying the exposure to heading, it is also important to identify the force associated with heading in football. the force gives an indication of the impact a header had on a player’s brain. studies in youth football, and in the laboratory, found the force of headers ranges between 4 and 50g, [7], well below the threshold of 80g associated with a concussive event. [10] it may, therefore, seem that the force associated with a header is not large enough to result in a concussion. however, little is known about the cumulative effect of heading on the brain. in other words, would the 6 headers of 50g a defender may make in a match (a cumulative force of 300g) affect their cognitive functioning, and could these sub-concussive events result in long-term decrements in brain health? the eye and brain share similarities in their neural and vascular structures and the immune response. [11] assessing the health and functioning of the eye, and any changes in these assessments that may occur can provide insight into the health and functioning of the brain. [12, 13]. the primary objective of this study was twofold, namely, to (i) assess the exposure to headers and concussions among elite female and male footballers, and (ii) explore the effect of headers and concussions on their ocular markers. a secondary objective was to determine the validity of self-reported exposure to heading compared to video analysis. methods study design an observational descriptive study design was conducted. ethical approval was provided by the medical ethics review committee of the amsterdam university medical centers (w22_016#22.045; amsterdam, the netherlands), while the study was conducted in accordance with the declaration of helsinki (2013). setting this study was coordinated by fifpro (football players worldwide), and a report of the study has been documented on their website (fifpro.org). [14] the women’s section of the study background: heading is a risk factor for neurogenerative disease in football. however, the exposure to heading in elite football training is understudied. objectives: the primary purpose of this study was to determine the exposure to headers in elite men’s and women’s football and to describe the effects of the headers on ocular markers. methods: exposure to headers was observed over three days of women’s and men’s football. the number of headers at each session was determined through video analysis, and the g-force was determined via an impact tracker. ocular markers were assessed at the start and end of the three days, and the results were compared to determine if there were any changes. self-reported exposure to heading was recorded after each session and compared to the number of headers observed through video analysis, to assess the validity of players’ self-reporting. results: female players made an average of 11 headers per player per session. ninety percent of the headers were below 10g, and none were above 80g. male players made an average of three headers per player per session, with 74% of the headers recording a g-force above 10g and 3% above 80g. no meaningful changes were observed post-session in the ocular markers, and no concussions were observed. neither cohort was able to accurately self-report exposure to headers. conclusion: longitudinal studies should be designed and conducted across different levels of play in both women and men’s football as a prerequisite to develop evidence-based measures to prevent or mitigate the potential risks associated with headers and concussions in elite football. keywords: soccer, professional, academy, ocular markers, force s afr j sports med 2023;35:1-6. doi: 10.17159/2078-516x/2023/v35i1a15236 http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15236 https://orcid.org/0000-0002-0126-4177 https://orcid.org/0000-0002-6064-038x original research sajsm vol. 35 no.1 2023 2 took place in june 2022 with the women’s israel football association’s academy (in collaboration with the israeli football players organisation ifpo; israel) during their final training week of the season. the men’s section of this study took place in the 2nd week of a training camp organised in march 2022 by jalkapallon pelaajayhdistys ry, football association of players in finland (jpy). all sessions (figure 1) were designed and executed by experienced coaches and no instruction was given to the coaches on the prescription of training. participants the participants consisted of two separate groups, namely, female and male elite footballers. in our study, the definition for an elite footballer was that he/she (1) trains to improve football performance; (2) competes in the highest or second highest national league; (3) reports football training and competition as their major activity, devoting several hours in all or most of the days for these activities, and (4) exceeding the time allocated to other types of leisure activities. convenience sampling was used to recruit the participants; namely, the female group from players at the women’s israel football association’s academy and the male group from players at the jpy training camp. based on a sample size calculation, 26 (13 per group) participants were required for the study. [15] measurements exposure to headers each session was filmed and all footage was analysed retrospectively by an experienced video analyst using a vlc media player (videolan client). each player was assigned a shirt with a unique identifiable number and an act head impact tracker, which they wore during each session (acttracker.com, northern sports insight and intelligence oy). the tracker measured any impacts to the head over a force of 10g. each observed header was noted and the timestamp of the header, whether the header was intentional, and the shirt number of the player was recorded. after each session, the players were also asked how many headers they thought they made during the session and their response was recorded. the timestamps of the impacts were aligned to the timestamps of the headers observed in the video footage, and the corresponding g-forces were recorded. any impact forces not associated with a header were not included in the analyses. concussions any suspected concussions were identified by a sideline spotter and assessed by medical staff present at every session. if a suspected concussion was confirmed by the medical staff, video footage of the incident was reviewed to identify the mechanism and cause of the concussion. ocular markers the ocular markers were assessed via the bioeye eyecon device at the start and end of the training week (bioeye.com). the measurements were conducted by a trained and experienced instructor. the eyecon test battery consists of four components: smooth pursuit (smp), pupillary light response (plr), near point convergence (npc), and horizontal gaze nystagmus (hgn). a description of each test, with normative values can be found in appendix 1. procedures potential participants were emailed the information about the objectives and procedures of the study by their respective national players union. if interested in the study, each participant gave their electronic consent and completed an electronic survey. the survey, compiled in english (typeform professional), consisted of several questions related to age, gender, height, weight, duration of their elite football career, studies and/or work outside of football, and field position. once completed, the data was saved on a secured server that only the two principal investigators had access to. each player was assigned a number, and no information regarding the identity of the player was recorded. players executed all sessions and measurements as indicated previously. players participated voluntarily in the study and did not receive any financial remuneration for their participation. data were collected in february, march and june 2022. statistical analysis for our primary objective, descriptive statistics (average, maximum and minimum) were used to analyse the players' exposure to headers and concussive events, and the results of the bio-eye assessments. for our secondary objective, the interclass correlation coefficient (icc) was used to determine the validity of self-reported exposure to headers compared to video analysis (gold standard). icc values were evaluated as follows: ‘poor’ validity when icc was lower than 0.50; ‘moderate’ validity when icc ranged from 0.50 to 0.75, ‘good’ validity when icc ranged between 0.75 and 0.90, and ‘excellent’ when icc values were above 0.90. [16] ibm spss 26 and microsoft excel for microsoft 365 were used to perform the data analyses. fig. 1. flowchart of study protocol original research 3 sajsm vol. 35 no.1 2023 results participants’ characteristics women players sixteen elite academy-level women participated in the study (n=16; 2 goalkeepers, 5 defenders, 4 midfielders and 5 forwards). one hundred percent (100%) of the footballers were currently studying, and 6% were working outside of football. the age of the players ranged from 14 to 18 years, with an average and mode age of 16 years. men players fifteen professional male footballers participated in the study (n=15; 1 goalkeeper, 5 defenders, 7 midfielders and 3 forwards). thirty-three percent (33%) of the footballers were currently studying, and 20% were working outside of football. the age of the players ranged from 22 to 33 years, with an average and mode age of 25 years and 22 years, respectively. exposure to headers women players a total of 746 headers were observed over the five training sessions, with an average of 149 headers per session (11 headers per player per session). however, 87% (n=650) of the headers were made in session 1 of day 2. due to player availability, the match on day 3 was cancelled and replaced with an extra training session. table 1 provides an overview of the average and maximum number and forces of the headers the players made. the force of the headers was not recorded during day 1’s sessions (players needed to be familiarised with the system, and the system needed to be calibrated). only 65 out of the 677 headers observed on days 2 and 3 (10%) had a g-force over 10g. the average force of the headers above 10g was 19g. no observed headers were above 80g in any of the sessions. there were two unintentional headers (0.3%), one had a g-force of less than 10g and the second had a g-force of 19g. figure 2 provides a visual of the number of headers made in each force zone. men players there was a total of 179 headers observed over the five sessions, with an average of 35 headers per training session (two headers per player per session) and 38 headers in the match (three headers per player). one hundred and thirty-two (132) out of the 179 headers had a force over 10g, 72% in training and 82% in matches. the average force of the headers above 10g was 19g in training, and 29g in matches. there were 175 intentional headers, with an average force of 19g, and four unintentional headers, with an average force of 77g. three headers in training, and two in the match had a g-force above 80g. an overview of the average and maximum number and forces of headers, and a visual of the number of headers made in each zone are shown in table 2 and figure 3, respectively. concussions, ocular markers and validity of self-report there were no observed concussions at any of the women’s or men’s training or match sessions. an overview of the results of the eyecon assessments, for women and men, are presented in table 3, with average scores and standard deviation. for both groups, the results of the changes in the smp, plr, and npc tests were within the normative range, suggesting no clinically relevant acute table 1. number and force of headers in women’s football training (n=16) day 1 day 2 day 3 session 1 2 1 2 1 maximum headers observed by a single player (n) 7 2 72 10 3 average headers observed per player (n) 4 <1 46 2 1 average self-reported headers per player (n) 11 1 33 2 1 intraclass correlation (icc) 0.11 0.73 0.49 0.94 0.88 icc interpretation poor good moderate excellent good average number of headers above 10g per player (n) 4 2 <1 average g force of headers above 10g (g) 19 17 17 number of headers above 80g (n) 0 0 0 maximum g force of a header (g) 71 27 22 fig. 2. number of headers made in each force zone in women’s football training original research sajsm vol. 35 no.1 2023 4 changes in cognitive functioning. there were no cases of hgn detected in either the women’s or men’s group. the validity of the women players to selfreport the number of headers they made during training ranged from poor to excellent between the sessions (table 1), and from poor to good for the men players (table 2). discussion the purposes of this study were (i) to assess the exposure to headers and concussions among elite footballers and (ii) to explore the effect of headers and concussions on their ocularmarkers. a secondary objective was to determine the validity of self-reported exposure to heading, compared to video analysis. female players made an average of 11 headers per player per session. ninety percent of the headers were below 10g, and none were above 80g. male players made an average of three headers per player per session, with 74% of the headers recording a g-force above 10g and 3% above 80g. there were no clinically relevant changes observed postsession in the ocular markers of the players, and no concussions were observed. neither the women’s nor men’s football cohort were able to accurately self-report the number of headers they made in every session. exposure to headers there was an average of 11 headers per player per training session in women’s football, and an average of two and three table 2. number and force of headers in men’s football training and match (n=15) day 1 day 2 match session 1 2 1 2 1 maximum headers observed by a single player (n) 3 16 15 3 5 average headers observed per player (n) <1 8 1 1 3 average self-reported headers per player (n) 1 6 3 2 3 intraclass correlation (icc) 0.07 0.77 -0.14 0.48 0.28 icc interpretation poor good poor poor poor average number of headers above 10g per player (n) <1 6 1 <1 2 average g force of headers above 10g (g) 11 17 34 32 27 number of headers above 80g (n) 0 1 1 1 2 maximum g force of a header (g) 13 101 111 94 137 fig. 3. number of headers made in each force zone in men’s football training and match table 3. changes in bioeye eyecon ocular markers between day 3 and baseline assessment results baseline day 3 change ocular assessments women men women men women men mean sd mean sd mean sd mean sd mean sd mean sd left eye smp latency (ms) 321 89 317 48 304 39 293 52 -17 108 -24 -37 right eye smp latency (ms) 279 66 297 63 291 46 269 56 12 63 -28 76 left pupil size (mm) 5.9 1.2 5.3 0.5 5.6 0.8 5.4 0.5 -0.3 1.5 0.1 0.6 right pupil size (mm) 5.9 1.1 5.4 0.6 5.5 0.8 5.4 0.5 -0.4 1.1 0 0.5 difference in pupil size (mm) 0.1 0.4 0.1 0.3 0.1 0.3 0.1 0.3 0.0 0.5 0 0.4 total pupil constriction (mm) 1.7 0.7 1.5 0.6 1.4 0.5 1.5 0.4 -0.3 1.0 0 0.4 npc loss of convergence (cm) 9.0 3.0 9.6 3.2 9.1 3.6 9.0 2.7 0.1 5.7 -0.6 4.2 npc regained convergence (cm) 9.0 2.9 9.0 2.7 9.0 2.7 9.1 2.1 0 4.7 0.1 3.0 smp, smooth pursuit; npc, near point convergence original research 5 sajsm vol. 35 no.1 2023 headers per player per session in training and matches in men’s football, respectively. the exposure to headers in men’s football is similar to that reported in previous studies in men’s and women’s collegiate and elite football, with an average of two headers per player per training session, [6, 17, 18] and four headers in matches, [5, 18] reported in both men’s and women’s football. although the number of headers we identified in women’s football was higher, 87% of these headers occurred in one session. if we exclude that outlying session from the calculation, there was an average of two headers per player per session in women’s football. this highlights the impact the design of a training session can have on the players’ exposure to heading, and a possible need to educate coaches on the importance of designing training sessions that limit the exposure of heading in training, to reduce the potential risk of repetitive headers on brain health. the average force of headers (calculated with those above 10g) in men and women’s football training was 19g. similar findings were found in collegiate players in a study by saunders and colleagues, with an average force of 20g and 17g for women and men players, respectively. [19] however, the percentage of headers above 10g, and the number of headers above 80g, was higher in men’s football when compared to women’s football. head impacts above 80g have been identified as a risk factor for concussion. [20] although our findings suggest that the men were exposed to headers with greater impacts than women, it is important to note that the men’s group was older than the women’s (senior vs academy). therefore, further research is required to describe the exposure to heading in men’s and women’s football, at different levels of play and different career stages. although 3% of headers in the men’s group were above 80g, the impacts did not cause a concussion. the risk of concussion may have been mitigated by a player’s well-developed neck musculature or proficient heading technique [21]; however, this investigation was beyond the scope of this study and research investigating the mechanism of heading-related concussions is recommended. ocular markers the exposure to headings over the three days of training, in women’s and men’s football, did not have a clinically relevant effect on the players’ ocular markers. a review of research related to heading in football found that in 75% of the studies reviewed, heading did not have a negative effect on cognitive functioning. [5] these findings suggest that the impact of headings may not have an acute effect on cognitive functioning. however, longitudinal studies are required to determine the chronic effect the impact of headings may have on cognitive functioning across multiple months or years of training and matches. the validity of self-report the validity of the players ability to self-report how many headers they made in a session ranged from poor to excellent, and poor to good, in women’s and men’s football, respectively. it is, therefore, recommended that in future research objective measures (i.e. video analysis) are used to quantify players exposure to heading in training and matches. limitations the purpose of a pilot study is to examine the methodology and procedures of a study on a small scale, and to explore the feasibility of the study and identify any limitations and considerations, before implementing the study on a larger scale. in this sense, this study was a success as several limitations and considerations were identified which can inform future directions. we observed the exposure to headings in men and women’s football. yet, although both groups compete at an elite level, the level of play, career stage, and the country where they played also differed between the groups. these factors may affect the level and style of training of the players, and the subsequent heading exposure. this can make it difficult to attribute differences between groups to a specific grouping factor (sex, level of play, etc.). we therefore recommend that future studies which analyse both men and women’s football consider the level of play, the country, and the career stage of the players. there were a few technical errors related to the synching of the timestamps of the head impacts with the video footage. namely, the time stamps from the head impacts during the men’s training camp were incorrect due to a software issue. this issue was fixed for the women’s training, but the video footage of the training was not time stamped. this meant that, although we were able to quantify the number of headers (and any other head impacts) each player made in a session, and the force of the head impacts that occurred, we were not able to objectively know the force of each header. future studies should therefore ensure that the impact trackers used are able to accurately record impacts from heading and that the recordings of training and matches is timestamped. convenience sampling was used for our recruitment of participants. therefore sampling bias must also be considered a limitation of the study. future directions the sequence of injury prevention is a sports injury prevention model that was developed to provide researchers and practitioners with a road map to guide decision-making and action plans when developing injury prevention strategies. [22] the first two steps of this model are (1) to establish the extent of the problem, (2) to establish the mechanism of injury, and to introduce preventative measures. we recommend that future studies start with the first two steps of this model, namely, to establish players' exposure (number and force) to head impacts in training and matches, and the incidence, severity, and mechanisms of changes in cognitive function (e.g. via ocular markers) in elite football. therefore, observational longitudinal (over at least one season) studies should be designed and conducted across different levels of play, in both women's and men’s football. these studies are a prerequisite before the development of any evidence-based measures aiming to prevent or mitigate the potential risks associated with headers and concussions in elite football. original research sajsm vol. 35 no.1 2023 6 conclusion female players made an average of 11 headers per player per session. ninety percent of the headers were below 10g, and none were above 80g. male players made an average of 3 headers per player per session, with 74% of the headers recording a g-force above 10g and 3% above 80g. there were no significant changes observed post-session in the ocular markers of the players, and no concussions were observed. neither the women’s nor men’s football cohorts were able to accurately self-report the number of headers they made in every session. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: we are thankful to all members of israeli football players organisation (ifpo) and jalkapallon pelaajayhdistys ry (jpy) who participated in the study. author contributions: sdh contributed to the analysis and interpretation of data and drafting and revision of the manuscript. vg contributed to the conception and design of the study, data collection, critical revision of the manuscript, and approval of the version to be published. references 1. nowinski cj, bureau sc, buckland me, curtis ma, daneshvar dh, faull rlm, et al. applying the bradford hill criteria for causation to repetitive head impacts and chronic traumatic encephalopathy. frontiers in neurology 2022;13. [10.3389/fneur.2022.938163]. 2. scottish fa heading guidance. scotland: scottish football association; 2021. [https://www.scottishfa.co.uk/media/9832/ heading-guidance-adult-football-18plus.pdf]. 3. professional football heading in training guidance. england: the football association; 2021. [https://www.thefa.com//media/thefacom-new/files/rules-and-regulations/202122/heading-guidance/professional-football-heading-intraining-guidance-july-2021.ashx]. 4. tierney gj, higgins b. the incidence and mechanism of heading in european professional football players over three seasons. scand j med sci sports 2021;31(4):875-883. [10.1111/sms.13900]. 5. langdon s, goedhart e, oosterlaan j, et al. heading exposure in elite football (soccer): a study in adolescent, young adult, and adult male and female players. med sci sports exerc 2022;54(9):1459-1465. [10.1249/mss.0000000000002945]. 6. bentley l, lauder m, smith n. heading incidence and characteristics in elite women's football over the 2020/2021 season. isbs proceedings archive 2022, p. 4. 7. mccunn r, beaudouin f, stewart k, et al. heading in football: incidence, biomechanical characteristics and the association with acute cognitive function-a three-part systematic review. sports med 2021;51(10):2147-2163. [10.1007/s40279-021-01492-z] 8. sandmo sb, gooijers j, seer c, et al. evaluating the validity of self-report as a method for quantifying heading exposure in male youth soccer. res sports med 2021;29(5):427-439. [10.1080/15438627.2020.1853541]. 9. harriss a, walton dm, dickey jp. direct player observation is needed to accurately quantify heading frequency in youth soccer. res sports med 2018;26(2):191-198. [10.1080/15438627.2018.1431534]. 10. broglio sp, schnebel b, sosnoff jj, et al. biomechanical properties of concussions in high school football. med sci sports exerc 2010;42(11):2064-2071. [10.1249/mss.0b013e3181dd9156] [pmc2943536]. 11. nguyen cto, acosta ml, di angelantonio s, et al. editorial: seeing beyond the eye: the brain connection. front neurosci 2021;15:719717. [10.3389/fnins.2021.719717] [pmc8276094]. 12. akhand o, balcer lj, galetta sl. assessment of vision in concussion. curr opin neurol 2019;32(1):68-74. [10.1097/wco.0000000000000654]. 13. oldham jr, meehan wp, 3rd, howell dr. impaired eye tracking is associated with symptom severity but not dynamic postural control in adolescents following concussion. j sport health sci 2021;10(2):138-144. [10.1016/j.jshs.2020.10.007] [pmc7987563]. 14. den hollander s, gouttebarge v. headers and concussions in elite football: a pilot project. netherlands: fifpro world players' union; 2022. [https://fifpro.org/media/kjicnd1a/headersand-concussions-in-elite-football.pdf]. 15. wang x, ji x. sample size estimation in clinical research: from randomized controlled trials to observational studies. chest 2020;158(1s):s12-s20. [10.1016/j.chest.2020.03.010]. 16. koo tk, li my. a guideline of selecting and reporting intraclass correlation coefficients for reliability research. j chiropr med 2016;15(2):155-163. [10.1016/j.jcm.2016.02.012] [pmc4913118]. 17. caccese jb, lamond lc, buckley ta, et al. linear acceleration in direct head contact across impact type, player position, and playing scenario in collegiate women's soccer players. j athl train 2018;53(2):115-121. [10.4085/1062-6050-90-17] [pmc5842901]. 18. kaminski tw, weinstein s, wahlquist ve. a comprehensive prospective examination of purposeful heading in american interscholastic and collegiate soccer players. sci med footb 2019;4(2):101-110. [10.1080/24733938.2019.1696470]. 19. saunders td, le rk, breedlove km, et al. sex differences in mechanisms of head impacts in collegiate soccer athletes. clin biomech (bristol, avon) 2020;74:14-20. [10.1016/j.clinbiomech.2020.02.003]. 20. patricios j, fuller gw, ellenbogen r, et al. what are the critical elements of sideline screening that can be used to establish the diagnosis of concussion? a systematic review. br j sports med 2017;51(11):888-894. [10.1136/bjsports-2016-097441]. 21. rutherford a, stephen r, douglas p. neuropsychology of heading and head trauma in association football (soccer): a review. neuropsychol rev 2003;13(3):153-179. 22. van mechelen w, hlobil h, kemper hc. incidence, severity, aetiology and prevention of sports injuries: a review of concepts. sports med 1992;14(2):82-99. [10.2165/00007256-19921402000002]. original research sajsm vol. 27 no. 3 2015 67 background. internationally young athletes are reported to have a poor understanding of the principles of sports nutrition and supplement use; hence their diet may be unhealthy and inappropriate for participation in sport. there is limited research on current nutritional knowledge and attitudes of under-16 (u16) age-group level rugby players in south africa (sa). objectives. to assess dietaryand supplement-related knowledge and attitudes of 198 u16 national-level rugby players in sa. methods. over a period of four consecutive years a total of 198 players attending nutrition workshops at the annual selection camp received and completed an anonymous structured questionnaire. anthropometric measures (weight, height and skinfolds) were gathered by registered biokineticists. results. of players 87% (168/193) indicated that they wanted to increase lean muscle mass, with 42% (82/194) feeling pressurised to do so by their coach and/or parents. almost half (85/196) believed their diets to be poor. players had better knowledge about nutrition recovery strategies than pre-game meals. seventy per cent (136/195) identified optimal timing and 56% (109/196) knew the ideal macronutrient composition of recovery meals. over 60% of players believed supplements were safe (115/192) and necessary (132/193) for increasing muscle mass, and almost half (106/195) believed they could take creatine. over a third (68/170) also believed that the protein quality of supplements was higher than that of food. supplements were primarily recommended by coaches and non-dietetic medical practitioners. eight of the players self-prescribed supplements and four were taking supplements on the advice of a store salesperson or representative. conclusion. the elite u16 rugby players in this study lacked comprehensive sports nutritional knowledge, yet had an overly positive attitude toward supplementation and used supplements haphazardly to achieve body composition goals. tailor-made nutrition interventions with a strong education component are recommended to improve players’ nutritional knowledge, as well as access to registered dietitians working in sport to advise on supplements. s afr j sports med 2015;27(3):67-71. doi:10.7196/sajsm.8092 initial investigation of nutrition and supplement use, knowledge and attitudes of under-16 rugby players in south africa k m duvenage,1 bsc (dietetics); s t meltzer,1,2 msc (med) (nutr & dietetics); s a chantler,1 msc (med) (exerc sci) 1 shelly meltzer and associates, cape town, south africa 2 division of human nutrition, department of human biology, university of cape town, south africa corresponding author: k duvenage (karliens@gmail.com) internationally, young athletes, including schoolboy rugby players, are reported to have a poor understanding of the principles of sports nutrition and unwarranted supplement use; as a result their dietary behaviours may be unhealthy and inappropriate for their sport.[1] the change in the level of professionalism of rugby has also had an effect on the younger age groups, by increasing the pressure for early muscle mass gains and strength, as within each age group heavier players seem to have a competitive advantage and are more likely to be selected for high-level teams.[2] since 1968 the average body mass of a craven week rugby player has increased by 10 kg (6.6%),[2] and the boys selected from this tournament for the south african (sa) schools team are roughly 8 kg heavier than the average weight of boys who do not make the team. this weight increase can to a large extent be attributed to increases in resistance training as part of the regular training of this age group.[2] the increased physiological and training demands for these younger players coincide with additional age-specific nutritional demands. these include consuming sufficient energy and nutrients for normal growth and development, maintaining adequate hydration, and ensuring appropriate timing and composition of meals for optimal performance and body composition.[3] the current consensus internationally is that the optimal way to meet these age and sport-specific demands is with a well-planned diet focusing on food and, if necessary, using supplements under the guidance of a qualified dietitian specialising in sport nutrition. only where an expert health professional identifies a specific dietary gap may select supplementation be used in conjunction with dietary optimisation.[4] unfortunately, in spite of this consensus, there is limited evidence with regard to the sport-specific nutritional needs of adolescents compared to adults, and in addition little is known about the physiological and psychological effects of supplementation in the under-18 age group.[4,5] the reality is that use of supplements by adolescent athletes is rife, and is of concern.[4] in a kwazulu-natal-based study in sa, 54 55.5% of rugby-playing school boys (age 16 17 years and under 13 years, respectively, n=222) reported using some form of supplementation.[5,6] moreover, the introduction and misuse of supplements may contribute to the increase in positive doping tests or steroid use in school-based sport, as well as an increase in other substance abuse (e.g. alcohol).[7,8] in a 2011 study on use of steroids in 20 rugby-playing schools (also in kwazulu-natal) it was found that 4.6% of the 9 824 male respondents had used androgenic anabolic steroids, and 2.7% of males were currently using them (hagemann g, 2014, personal communication). nutritional supplements are often viewed as a ‘safety net’ by young athletes, because they lack the appropriate knowledge relating to the 68 sajsm vol. 27 no. 3 2015 quantity and quality of their dietary intakes. [5] a single rugby-specific questionnairebased study in ireland showed nutrition knowledge (based on a composite score) to be poor among young rugby players (age 15 18 years).[1] other studies in adolescent athletes in other sports have shown a similar trend.[5,9-13] in a recent sa study varsity cup players’ (mean (standard deviation (sd) age 21.9 (1.2) years) habitual dietary intakes and match-day strategies were found to be suboptimal, and supplement use was high. [14] in other studies supplement use has also been linked to pressure from coaches, peers, competitors and parents,[4,6] often reinforced by unsubstantiated and exaggerated claims made by an industry which is practically unregulated.[4] rugby is one of the major team sports in sa, with a total of 633 299 rugby players registered in the country in 2013, and a following of around 10 million.[9] of the registered players, 82% are preteens and teens.[9] the culture formed at school level can be taken through to higher-level rugby, making this group of athletes a large target for possible research and nutritional intervention. currently there are no published studies on the knowledge, attitudes and practices of nutrition and use of supplements among elite/high-level adolescent rugby players in sa. this is an important area to study as intervention studies have previously shown that better knowledge can positively effect nutritional practices.[13] the objective of this study was to investigate the nutrition knowledge, basic attitudes and supplement use of four different groups of national-level under-16 (u16) rugby players over 4 consecutive years. methods subjects and questionnaire in july of every year in sa a national selection panel identifies the top 50 u16 players at grant khomo week, which is the national u16 tournament. the top 50 players then attend a camp in the school holidays and receive specialist training in their positions as well as in life skills, technical aspects of coaching, conditioning, nutrition and mental preparation. during this camp, over a period of 4 consecutive years (2009, 2010, 2011 and 2012), a total of 198 male players attended the workshop and were given a dietary questionnaire specifically designed for this study. the questionnaire was designed as a pre-workshop investigation by targeting basic ideas and concepts with a low responder burden. many of the questions were similar to those asked in standard dietary consultations with this age group. the questionnaire had been proofread and tested by an expert external panel of non-dietetic staff members of the university of cape town and the sports science institute of sa (ssisa). the questionnaire comprised four sections with 18 questions in total. the overall design of the questionnaire is displayed in table 1. at the start of the dietary workshops the questionnaires were handed out and completed by the players, before they received any nutrition information. the players completed the questionnaires in the presence of at least one dietitian with sports nutrition experience to help with questions, and other staff members of the team to ensure minimal peer influences between participants. they were assured that all information gathered would be confidential and no names were recorded on the questionnaire; results would not be shared with coaches or trainers, and only participant numbers would appear on questionnaires. anthropometric data were gathered by registered and trained biokineticists (of the discovery high performance centre at ssisa). it was therefore expected that the inter-rater variability would be relatively low. each player was weighed on an electronic scale (mvw industrial floor scale, 200 kg capacity) while barefoot and wearing only shorts and a t-shirt. height was recorded with the subject barefoot with his arms hanging by his sides. his heels, buttocks, upper back and head were in contact with the stadiometer (seca leceister 214, england). the percentage body fat was calculated from the sum of four skinfold sites (triceps, biceps, subscapularis and supra-iliac), me asure d using har p enden sk infold callipers, all measurements taken on the right side of the player. as there are no norms for athletic populations, we interpreted weight, height and body mass index according to the world health organization (who) standard guidelines for age[15] as well as boksmart references.[2] body fat composition was compared with the norms described by durandt et al.[16] each player gave informed written consent to participate and complete the anonymous questionnaire. parental consent was given as part of the indemnity to attend the sa rugby union camp. statistical analysis a database for data entry was prepared using microsoft excel. descriptive statistics together with frequency statistics were used to summarise the main observations. questions were grouped by the frequency of the answer. table 1. design of the questionnaire section a: mainly open-ended questions: weight, height, age, self-reported position of play body composition goals section b: multiple-choice questions: knowledge of basic nutrition with regard to weight management, prematch nutrition, recovery nutrition section c: four-point likert scale: attitude and beliefs towards their own diets and supplements section d: open-ended questions: supplement use dosages who recommended table 2. mean (sd) weight, height and body fat of participants over the 4 years of the study 2009 (n=49) 2010 (n=49) 2011 (n=50) 2012 (n=51) weight (kg) 84.9 (11.4) 85.7 (15.0) 86.4 (14.2) 86.2 (15.0) height (cm) 179.2 (7.8) 177.3 (14.1) 180.6 (8.8) 179.2 (7.8) body fat (%) 18.9 (3.9) 20.3 (4.3) 18.9 (4.3) 19.6 (4.3) sajsm vol. 27 no. 3 2015 69 as some participants left some questions blank, the n-value was adjusted for the each question. parametric data are presented as mean (sd). analysis of variance measures were used to compare anthropometry between groups (forwards/backs) and years (4 years). frequencies of knowledge, attitude and practices regarding nutrition and supplementation were compared using χ2 tests. statistical significance was based on a p-value of <0.05, and all data were analysed using statistica version 10 (statsoft inc., usa). results table 2 presents the mean (sd) weight, height and body fat of the participants over the 4 years. during this time average weight ranged from 84.9 (11.4) kg to 86.4 (14.2) kg, height ranged from 177.3 (14.1) cm to 180.6 (8.9) cm, and body fat ranged from 18.9% (3.9%) to 20.3% (4.3%). there were no significant differences from year to year with regard to mean weight, height or body fat percentage. the mean weight and height of the players were above the 50th percentile for their age according to the who[15] and in accordance with norms for their age and level according to boksmart.[2] the mean body fat percentage was slightly above the norm, but was not position specific.[17] body composition goals eighty seven per cent of the players (168/193) indicated that they wanted to increase lean muscle mass. basic nutritional knowledge the most frequent answers by participants to the nutritional knowledge questions are presented in table 3. although there was slight annual variation, there was no significant difference between the years. attitudes and beliefs towards diet and supplements the questions regarding dietary attitudes and beliefs had responses on a standard likert scale. table 4 presents the frequency of those who ‘agreed’ or ‘strongly agreed’ with the statement given. forty three per cent of the participants agreed that they had a poor diet, while the majority (68%) agreed that they needed a protein supplement to gain muscle mass, which almost half of them (42%) felt pressurised to do. although most of the participants (66%) did not agree that they needed supplements to perform at their peak, the majority (60%) indicated that taking supplements would not result in a positive doping test and that they could take creatine at their age (54%). supplement use over the 4-year period 84 (42%) of the players reported that they were taking at least one supplement, with two players taking as many as five different supplements simultaneously (fig. 1). dosages and frequency were not provided. protein supplements were the most prevalent supplement used (31%). there was no statistically significant difference in supplement use over the course of each year. table 5 shows a summary of who recommended the use of the supplement. table 3. nutritional knowledge by highest frequency answer of the participants by year question answer with highest score, % (n/n) 2009 2010 2011 2012 average* most ideal strategy to avoid gaining fat mass cut out all sugar – 38 (18/48) eat a low-fat, balanced diet – 46 (22/48) eat a low-fat, balanced diet – 40 (19/47) eat a low-fat, balanced diet – 29; eat more protein – 29 (14/48) eat a low-fat, balanced diet – 37 (n=191) best meal to have the night before a match creamy pasta alfredo – 83 (40/48) creamy pasta alfredo – 68 (34/50) creamy pasta alfredo – 69 (33/48) creamy pasta alfredo – 62 (31/50) creamy pasta alfredo – 70 (n=196) optimum time for a recovery meal 30 40 min – 67 (32/48) 30 40 min – 73 (36/49) 30 40 min – 69 (33/48) 30 40 min – 70 (35/70) 30 40 min – 70 (n=195) what ideal recovery snack should contain protein and carbohydrate – 51 (24/47) protein and carbohydrate – 51 (26/51) protein and carbohydrate – 60 (29/48) protein and carbohydrate – 60 (30/50) protein and carbohydrate – 56 (n=196) *mean frequency of the dominant answer over the whole sample. table 4. attitudes and beliefs about diet, muscle mass, protein and supplements, % (n/n) 2009 2010 2011 2012 average* i rate my diet as poor or very poor 49 (23/47) 33 (16/49) 50 (25/50) 42 (21/50) 43 (85/196) i feel pressurised by my coach and/or parents to increase my lean body mass 48 (22/46) 43 (21/49) 37 (18/49) 42 (21/50) 42 (82/194) i believe that i would have to take a protein supplement to increase muscle mass 70 (32/46) 72 (36/50) 68 (32/47) 64 (32/50) 68 (132/193) i believe the quality of protein in a supplement is higher than that of food 47 (18/38) 42 (18/42) 22 (9/41) 48 (23/48) 40 (68/170) i need a supplement to perform at my peak 30 (14/47) 48 (24/50) 22 (11/49) 37 (18/49) 34 (67/195) i don’t think that taking a supplement can lead to a positive doping test 65 (31/48) 63 (31/49) 48 (22/46) 63 (31/49) 60 (115/192) i believe i can take creatine 50 (24/48) 55 (27/49) 60 (29/48) 52 (26/50) 54 (106/195) *mean frequency of the dominant answer over the whole sample. 70 sajsm vol. 27 no. 3 2015 discussion in this descriptive survey of elite u16 sa rugby players it was evident that while the participants had better knowledge about recover y strategies than other general nutritional practices for athletes, their attitudes demonstrated a desire to increase lean muscle mass without the appropriate nutritional knowledge to do so. it was also evident that the perceived pressure to increase lean mass was from external sources. this pressure may have contributed to nearly half of these adolescents taking one or more dietary supplements, believing these to be safe and necessary for increasing muscle mass, while many believed their diets were poor. of further concern is the lack of professional specialised nutritional advice given to this age group. the players had a mean body weight of 85.8 (13.9) kg, with the expected differences found between forwards and back-line players. when related to the who growth charts, they were above the 50th percentile for their age-appropriate weight and height. this is expected due to their sport and level of play. however, when compared with available sa literature on rugby players[2,17] their weight, height and body fat percentage were in line with the norms for their age and level of sport. in spite of this, players reported feeling pressure to gain more muscle mass. this is not surprising, and may arise from the competitive advantage that increased body size may give in rugby, as those who make the sa schools u18 team are on average ~8 kg heavier than those who do not. [2] poor nutritional knowledge may negatively affect ability to alter body composition for performance. in our study, while the players’ knowledge on the best strategy to avoid gaining fat mass was mixed (37% suggested a low-fat balanced approach), nutrient-based knowledge questions on recovery were better answered than those on pre-match meals. players tended to have a better knowledge on the timeframes and macronutrient content of recovery nutrition, which is somewhat understandable given that ‘recovery strategies’ are a much publicised and marketed aspect of sports nutrition and supplements. for the prematch meal the majority (70%) of participants chose pasta alfredo, without questioning the fat content of the sauce. this may indicate the need for food-based nutritional interventions, as the relationship between dietary education and a positive effect on knowledge has been highlighted in other intervention studies.[1,13] resorting to supplements as a means to build muscle mass rather than improving their diets is problematic. although most players did not believe that supplements were required for peak performance, it is of concern that 68% believed that protein supplements were required for increasing muscle mass and almost half of the players believed that they could take creatine. this despite the fact that the international consensus on creatine use suggests that it should be limited to experienced and well-matured athletes, because it may lead to increased injuries and have a gateway effect.[4,5] several international studies[4-6,10-13] of both elite and school-level adolescents in western countries have indicated that supplements are commonly used, particularly by athletes who do weight training. in international research the type of supplements most commonly used varied somewhat depending on the study, but included multivitamins and single-nutrient supplements, e.g. vitamin c, protein powders, amino acids, creatine and sport drinks, which is similar to what was found in our study.[6,12] a notable difference is that in our study we found that pre-workout supplements and fat-cutters were also being used. as has b e en found pre v iously, [5,6] supplements were primarily recommended by coaches and medical practitioners (other than dietitians). this is of concern as a dietitian is uniquely qualified to assess each player’s diet and to make recommendations accordingly.[4] the process of prescribing a supplement is an intensive one that requires an understanding of each player’s habitual diet, medical history, lifestyle, access to food and training programme and periodisation. a dietitian can recommend the appropriate dietary principles to prevent deficiencies and optimise performance through a ‘food first’ approach and, if warranted, prescribe a supplement to be integrated into the overall nutrition plan.[3,4] given the current supplementation and doping climate, it is alarming that the majority of boys did not think there were risks involved in supplement use, nor did they consult specialised health professionals for advice. of further concern is the evidence that supplements are being used despite the lack of long-term safety data, and without dietary-intake assessment to determine if 40 30 20 10 0 pe rc en ta g e (% ) 1: protein powder 2: liquid meal supplement and recovery formulas 3: creatine 4: carbohydrate or energy drinks 5: combination or single vitamin and mineral supplement 6: preworkout 7: glutamine 8: omega 3 and/or omega 6 fatty acids 9: nonspeci�c 10: other 11: amino acids 12: fat cutters or burners 1 2 3 4 5 6 7 8 9 10 11 12 fig. 1. types of supplements and prevalence (%) reported by players (n=150). table 5. who recommended the use of supplements supplement advisor players (n=84), n (%) non-nutritional medical staff (general practitioner, physiotherapist, pharmacist, or biokineticist) 19 (22) coaches, rugby unions, other rugby teams 17 (20) self 8 (10) gym instructor or gym 6 (6) family and friends 8 (5) supplement representative or store 4 (5) dietitian 2 (2) sajsm vol. 27 no. 3 2015 71 supplementation is required. over a third (40%) of the players also seemed to believe that the protein quality in supplements is higher than that of food. this has also been evident in american high school football and volleyball players[10 ]and high-school athletes. [18] in terms of risk management, the ‘food first’ approach is becoming the international norm, supported by a best practice supplement protocol managed and directed by the team dietitian.[3,4,19] the australian rugby model[19] is a superb example of such a systematic best-practice approach. buy-in to a national system like this would give professional players at all levels confidence in the system, as they would have an avenue where they know they can ask for reliable information. ultimately this system could filter down through the age groups to create a culture of positive nutritional choices with strategic supplement use. this approach would have merit in sa, as in our study it was alarming to see that 10% of players self-prescribed supplements, with 5% taking supplements on the advice of a store salesperson or representative. young athletes are often easily influenced by strong marketing strategies,[4,5] yet there is limited evidence to show efficacy and safety of sport supplements in adolescents.[4,5,18] of course another concern is the gateway theory linking the regular use of supplements to alcohol, marijuana and androgenic anabolic steroids among college students.[7,8] this is exacerbated by the lack of regulation within the marketing and production of supplements, aggressive marketing and the high risk of contamination.[4,5] study limitations in the present study an observational questionnaire in a relatively small but elite sample was used, and thus the generalisation of results is limited. however, the findings do give some important insights into the nutrition and supplement habits of players in this age group. ideally the questionnaire should be validated further in a larger sample, with focus groups to capture qualitative data, and the same participants should be reassessed at a follow-up session to see if their knowledge on nutrition and supplement use improved. conclusion the elite u16 rugby players participating in this study lacked solid sports nutritional knowledge and were using supplements haphazardly to achieve goals. this is out of date with international best practice nutrition and supplement approaches. for example, australia has introduced a comprehensive sports supplement policy,[18] which acknowledges the use of supplements but only if used appropriately and supported by a nutritional programme to ensure player health and safety. this has been adapted by some sports federations, including the australian rugby union (aru), which has established a supplement advisory group[19] to ensure strict measures with regard to supplement use, and decreed that all australian national teams and super-rugby clubs appoint a fully qualified and accredited sports dietitian who is responsible for overseeing the provision of supplements at the club. players need prior consent from their team sports dietitian and written approval from the aru supplement advisory group for use of any supplement which has not been preapproved. all supplement use by clubs and players is detailed on a centrally documented system. another key feature of the programme is improved player education.[19] this model should be investigated to see how it could be adapted to our local environment. the importance of education and research as key focus areas is evident. clubs and players should be encouraged to engage the services of a registered dietitian working in sport to improve dietary knowledge and practices, as well as when considering taking a supplement. education focusing on the positive role of good nutrition and supplements should be extended to general practitioners and support staff. coaches specifically need to be involved and to promote the same message, as they are known to be the greatest influence on supplement choices.[5] it goes without saying that proactive research programmes are essential to evolve best practice protocols. acknowledgements. we thank the sa rugby union and the discovery high performance centre at the ssisa for their assistance and support in this project. references 1. walsh m, cartwright l, corish c, sugrue s, wood-martin r. the body composition, nutritional knowledge, attitudes, behaviors, and future education needs of senior schoolboy rugbyplayers in ireland. int j sport nutr exerc metab 2011;21(5):365-376. 2. lambert m, forbes j, brown j. sa rugby boksmart: age vs weight category – rugby, 2010. www.sarugby.co.za/boksmart/pdf/boksmart%202010-age%20vs%20 weight%20category%20rugby.pdf (accessed 3 september 2014). 3. lanham-new sa, stear sj, shirreffs sm, collins al. sport and exercise nutrition. 1st ed. oxford: wiley-blackwell, 2011:316-322. 4. south african institute of drug free sport. position statement of the south african institute of drug free sport (saids) on the use of supplements in sport in schoolgoing youth, 2011. http://www.sasma.org.za/articles/saids%20position%20 statement%20for%20youth.pdf (accessed 3 september 2014). 5. strachan k. current perceptions and usage practices of nutritional supplements amongst adolescent rugby-playing school boys from the kwazulu-natal region. masters in nutrition thesis. stellenbosch university, 2009. 6. steenkamp a, meltzer s, harbron j, readhead c. the use of dietary supplements in south african rugby players participating in the under 13 coca-cola craven week tournament. bmed sci hons (nutrition and dietetics) thesis. faculty of health sciences, university of cape town, 2013. 7. buckman jf, yusko da, white hr, pandina rj. risk profile of male college athletes who use performance-enhancing substances. j stud alcohol drugs 2009;70(6):919-923. 8. hildebrandt t, harty s, langenbucher jw. fitness supplements as a gateway substance for anabolic-androgenic steroid use. psychol addict behav 2012;26(4):955-962. [http://dx.doi.org/10.1037/a0027877] 9. south african rugby union. south african rugby union annual report 2012. http://images.supersport.co.za/saru%20annual%20report%202010.pdf (accessed 30 september 2014). 10. mason ma, giza m, clayton l, lonning j, wilkerson rd. use of nutritional supplements by high school football and volleyball players. iowa orthop j 2001;21:43-48. 11. nieper a. nutritional supplement practices in uk junior national track and field athletes. br j sports med 2005;39:645-649. [http://dx.doi.org/10.1136/bjsm.2004.015842] 12. mcdowall ja. supplement use by young athletes. review article. j sports sci med 2007;6:337-342. 13. massad sj, shier nw, koceja dm, ellis nt. high school athletes and nutritional supplements: a study of knowledge and use. int j sport nutr 1995;5(3):232-245. 14. potgieter s, visser j, croukamp i, markides m, nascimento j, scott k. body composition and habitual and match-day dietary intake of fnb maties varsity cup rugby players. s afr j sports med 2014;26(2):35-43. [http://dx.doi.org/10.7196/sajsm.504] 15. world health organization. the who child growth standards. http://www.who.int/ childgrowth/standards/en/ (accessed 18 february 2014). 16. durandt j, du toit s, borresen j, et al. fitness and body composition profiling of elite junior south african rugby players. s afr j sports med 2006;18(2):38-45. 17. duellman mc, lukaszuk jm, prawitz ad, brandenburg jp. protein supplement users among high school athletes have misconceptions about effectiveness. j strength cond res 2008;22(4):1124-1129. [[http://dx.doi.org/10.1519/jsc.0b013e31817394b9] 18. australian rugby union limited. sports supplement policy, effective from 17 february 2014. http://www.rugby.com.au/portals/1/pdfs/administration/sport%20supliments%20 policy/20140610_arusportssupplementspolicy.pdf (accessed 1 september 2014). 19. australian institute of sport. ais sports supplement framework. http://www.ausport. gov.au/ais/nutrition/supplements (accessed 9 march 2015). original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license investigation of the knowledge of south african high school rugby coaches on concussion and the return-to-play protocol nc abel,1 mbchb, msc; cc grant,1 phd; dc janse van rensburg,1,2 mbchb, phd 1 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 2 international netball federation, manchester, uk medical board member, uk corresponding author: nc abel (nicoabel@icloud.com) research suggests that players are more likely to report a concussion to their coaches than to anyone else.[1-6] the role of the coach is therefore central in creating a culture that supports seeking medical assistance and adherence to treatment. studies by mathema et al. and mrazik et al. showed that rugby and hockey coaches scored above 80% to 90% in overall concussion knowledge, with scores in the 60% to 70% range for return-to-play (rtp) guidelines.[1,2] south african amateur rugby union coaches scored 74% when their concussion knowledge was tested by van vuuren et.al. however, this study also showed that the coaches have insufficient knowledge regarding rtp.[6] although the literature shows that coaches have a good general knowledge of concussion, they may occasionally make inappropriate decisions regarding its management. for example, international research showed that 40% of coaches are willing to put pressure on concussed players to remain playing, while 28% of coaches might pressure the medical staff to allow a concussed player to continue with the game. [6] furthermore, 39% of coaches may allow a player to continue to play if the player indicated being fine after being knocked out.[2] coaches are often influenced by the importance of the game when making decisions to allow a concussed player to continue playing. in wrestling, 27% of coaches admitted that they would allow a potentially concussed wrestler to continue wrestling in a regional qualifier compared to 12% of coaches who stated they would allow this to happen in the first match of the season.[7] studies covering the testing of the knowledge of players and coaches reported certain collective misconceptions and gaps in their knowledge. players often do not know that sleep disturbance and emotional symptoms are related to concussions.[8,9,10] the importance of cognitive rest is often not well understood as part of the recovery process,[1,4] and there are also misunderstandings about the significance of a player’s loss of consciousness during a game. in studies by mathema et al. [1] and guilmette et al.,[11] only 55% of players and 61% of coaches respectively, felt that a player should be removed from the field after being knocked unconscious. little is known about this topic in rugby union games at school level, where the coaches are often teachers and not professional coaches. the boksmart national rugby safety programme a joint rugby safety initiative between sa rugby and the chris burger/petro jackson players' fund – was founded in south africa in 2009. an original development priority of the boksmart programme was to improve player safety in specific rural, as well as urban, school settings by increasing the knowledge of rugby coaches, referees and players. coaches are required to keep their boksmart accreditation up to date. research on the subject in the south african high school rugby setting is sparse. this study was designed to investigate the knowledge of south african high school rugby coaches on concussion symptom recognition, general concussion knowledge and stepwise rtp protocols. background: coaches are pivotal in the management of concussed players. assessing the knowledge of high school rugby coaches with regard to concussion management will enable relevant future education on this topic to be covered. objectives: to investigate the knowledge of south african high school rugby coaches on concussion symptom recognition, knowledge and stepwise return-to-play (rtp) protocols. methods: a cross-sectional descriptive study involving 143 first team, high school rugby coaches was completed via an electronic questionnaire. independent variables included coach demographics, qualifications, experience, boksmart accreditation, and school size. dependent variables included knowledge scores on concussion symptoms, general concussion knowledge, stepwise rtp and maddocks questions. relationships between total scores for different demographic groupings were established using non-parametric techniques. results: the coaches had high general, symptom and overall concussion knowledge scores (77% 80%) in contrast with low rtp scores (62%) and very low maddocks questions knowledge scores (26%). the 35-44-year age group received top scores for symptom recognition (p=0.034) and total concussion knowledge (p=0.041). larger category school coaches (p=0.008) and boksmart accredited coaches (p=0.041) outperformed all other coaches in general concussion knowledge and total knowledge, respectively. however, respondents were not familiar with emotional symptoms or the importance of cognitive rest after a concussion. educational programmes were the most popular knowledge source for coaches. conclusion: in general, coaches presented with good general concussion knowledge but lesser expertise on emotional symptoms, cognitive rest and rtp management. modifiable predictors of knowledge included the expansion of boksmart accreditation, focussing information sessions on smaller rugby size schools and the education of coaches younger than 35 years or older than 45 years of age. keywords: youth, sports concussion, boksmart, maddocks questions, traumatic brain injury s afr j sports med 2022;34:1-7. doi: 10.17159/2078-516x/2022/v34i1a12255 mailto:nicoabel@icloud.com http://dx.doi.org/10.17159/2078-516x/2022/v34i1a12255 https://orcid.org/0000-0003-1058-6992 https://orcid.org/0000-0003-1333-1119 https://orcid.org/0000-0002-4719-6472 original research sajsm vol. 34 no.1 2022 2 methods study design a cross-sectional, descriptive study was conducted after approval was granted by the institutional research ethics committee of the faculty of health sciences, university of pretoria. an invitation to participate in the project was addressed to high school coaches representing all south african provinces. the letter, including the study background, confirmation of institutional ethical approval, consent form, questionnaire, and letter of support from the south african rugby union (saru) medical committee and the director of sport concussion south africa, was distributed on five separate occasions (four to six weeks apart) during an eight-month period. data from the submitted questionnaires were exported to a microsoft excel file and analysed. the anonymity of all respondents was maintained by including only a study number for participants and no personal details. the questionnaire was piloted prior the start of the study, using eight coaches at local high schools. coaches recorded their questionnaire completion times and provided comments on the questionnaire’s contents and usability. data independent variables (predictors) included the demographics of the coaches, coaching qualifications, years of experience as a coach, boksmart accreditation status, and the size of the school where the coach coached. schools were categorised as ‘small’ if they had less than five rugby teams; ‘medium’ if between five and ten teams were active; and ‘large’ if more than ten teams were present. dependent variables (outcomes) that were measured included the scores on the knowledge of concussion symptoms, general concussion knowledge, knowledge of the stepwise rtp, maddocks questions, and knowledge sources from which the coaches obtained their knowledge. symptom recognition, general concussion knowledge questions and sources of knowledge were assessed from validated questionnaires.[2,5,9,11] emotional symptoms were specifically included in the list of symptoms to investigate the understanding of these symptoms in relation to concussion.[4] rtp questions were designed by the researcher, together with open-ended questions, on the coach’s knowledge of the maddocks questions. the questionnaire is attached as supplement a. statistical analysis knowledge scores were calculated as a combination of the seventeen yes/no questions on symptom recognition and eight true/false questions on general questions about the coaches’ attitude towards concussion. the maximum knowledge score was therefore 25 points. true/false questions were used to obtain rtp scores and included scenarios regarding same-day rtp (four questions), time out from sport following concussion (four questions), symptom occurrence during stepwise rtp (four questions), cognitive rest (four questions) and the importance of seeing a doctor (five questions). the maximum rtp score was 21 points. the knowledge of the maddocks questions was tested through open-ended questions and scored a maximum of five points. frequency tables, including counts and percentages, were used to present the responses to the incorporated demographic questions. means and standard deviations (sds) were calculated for the total scores of each subsection. due to the presence of small and/or uneven sample sizes within the groups, relationships between total scores for different demographic groupings were also established using nonparametric statistical techniques. when two groups were compared, the wilcoxon two-sample test was used, and when more than two groups were compared, the kruskal-wallis test was used, followed by a bonferroni multiple comparison test to identify which pairs differed significantly. results coaches’ background information a total of 640 surveys were distributed and 143 responses were returned. the coaches’ number of years of experience is presented in table 1. most of the representation (47%) came from three rugby unions, including the golden lions (17%), boland (16%) and the blue bulls (14%). coach age, level of education and accreditation table 2 shows that more than half of the coaches (96 of 143) completed level 2 or level 3 coaching courses; however, seven percent of coaches (10 of 143) had completed no coaching courses. most of the 35–44-year-old coaches (15 of 37) with more years of experience are from the large category schools (41%). the small category schools have a larger number of the table 1. distribution of coaches’ years of experience (n=143) years’ experience (%) < 3 years 3 – 5 years 5 10 years > 10 years 5 15 19 61 table 2. age groups, level of coaching attained, school categories and boksmart accreditation of coaches age (years) n world rugby course level category of school boksmart accreditation none 1 2 3 small medium large < 24 13 30.8 (4) 38.5 (5) 30.7 (4) 46.2 (6) 23.0 (3) 30.8 (4) 61.5 (8) 25 34 54 7.4 (4) 31.5 (17) 61.1 (33) 40.7 (22) 38.9 (21) 20.4 (11) 100.0 (54) 35 44 37 2.7 (1) 27.0 (10) 62.2 (23) 8.1 (3) 24.3 (9) 35.1 (13) 40.6 (15) 100.0 (37) 45 54 30 3.3 (1) 16.7 (5) 76.7 (23) 3.3 (1) 16.7 (5) 53.3 (16) 30.0 (9) 93.3 (28) 55 64 9 66.7 (6) 33.3 (3) 33.3 (3) 22.2 (2) 44.5 (4) 100.0 (9) all 143 7.0 (10) 25.9 (37) 62.2 (89) 4.9 (7) 31.5 (45) 38.5 (55) 30.0 (43) 95.1 (136) data are expressed as percentage % (sample number, n) original research 3 sajsm vol. 34 no.1 2022 coaches (6 of 13) under 24-years-ofage (46%). most (95%) of the coaches are boksmart accredited (136 of 143), but only 62% of the <24-year age group reported boksmart accreditation (8 of 13) and none of the below 34-years old progressed to the third level of the world rugby course. concussion symptom recognition figure 1 shows the symptoms identified by coaches as the most common signs and symptoms of concussion, and the percentages of coaches who were able to recognise them (ranked from most to least). headache, confusion, loss of consciousness and dizziness were recognised as symptoms and signs of concussion by more than 90% of the respondents. amnesia was recognised by 73% of respondents, while sleep disturbance was only recognised by 55% of participants. emotional symptoms such as irritability (41%) and sadness, including inappropriate crying, were less likely to be recognised as concussion symptoms (24%). from the open-ended questions on the two most common symptoms of concussion, the most recognised symptom was confusion (64%). this was followed by dizziness and nausea (35%) and headaches (32%). amnesia (14%) and loss of consciousness (8%) were not rated as a common symptom or sign of concussion. emotional symptoms were mentioned only twice and sleep disturbances were not mentioned at all as common symptoms of concussion. general concussion knowledge more than 90% of the coaches reported that it was easier to sustain another concussion following a previous concussion. furthermore, 95% reported that concussion is a potentially serious injury that can lead to permanent damage, that loss of consciousness was not a prerequisite for concussion to be present, and that a concussed person must see a medical doctor after the injury. nearly 70% of the participants reported that symptoms can take time to appear after the injury. however, less than 50% reported that it was difficult to diagnose concussion and that one does not have to hit one’s head to sustain a concussion. table 3 shows that the average score for symptom recognition/ knowledge and general concussion knowledge was very high (above 78%). however, the rtp knowledge was mediocre (62%) and knowledge of the maddocks score was poor (26%). fig. 1. concussion symptom or signs recognition by coaches. table 3. mean participant scores and percentages on various concussion knowledge questions variable maximum score mean (sd) mean score (%) range symptom recognition /knowledge* 25 19.5 (2.0) 78 13 – 24 general concussion knowledge 8 6.4 (1.1) 80 4 – 8 return-to-play† 21 13.1 (1.5) 62 9 – 16 maddocks score** 5 1.3 (1.2) 26 0 – 5 * refers to questions 8 and 10 (maximum score = 25) scores for symptom and general concussion knowledge. ** refers to maddocks score (maximum score = 5) scores for knowledge on maddocks questions. † refers to questions 11 – 15 (maximum score = 21) scores for return-to-play knowledge. fig. 1. sources of knowledge original research sajsm vol. 34 no.1 2022 4 source of knowledge figure 2 indicates that the most popular choice of knowledge source was educational programmes, such as the boksmart programme (listed as 40% of first choices and 28% of second choices). the second most popular choice was knowledge gained through working with healthcare providers (39% as first choice and 24% as second choice). these two choices accounted for 68% of the first choice votes and 63% of the second choice votes. use of the internet was a less likely used source of knowledge (45%). influence of independent variables on dependant variables table 4 provides a concise summary of the statistically significant findings on the influence of independent variables on dependent variables. results indicated that coaches in the 35–44-year age group, those from large category schools and those with boksmart accreditation showed significantly higher scores regarding concussion knowledge. discussion this study is one of the first to test the concussion knowledge of south african high school rugby coaches. participants in this study showed high general symptom recognition and overall concussion knowledge (77% to 80%). the score of 78% for symptom knowledge in this group is comparable with the scores of welsh elite and semi-professional rugby union coaches (77%),[1] and comparable with the knowledge of south african amateur club coaches (74%).[6] impressively, the score is only seven percent less than the average scores of medical professionals in the latest canadian research.[10] however, low rtp (62%) and very low maddocks question knowledge scores (26%) were found, perhaps indicating that coaches do not have sufficient knowledge to adequately manage the rtp of concussed players. this supports the findings of van vuuren et.al.(6) in south african amateur club coaches. boksmart accreditation, the size of the school and the age group of the coaches were identified as predictors for superior knowledge, while coaches at small schools were identified as a possible group with sub-standard knowledge of concussion. misunderstandings about key concepts of concussion are also true for the latter group. experience and qualifications literature indicates that years of experience as a coach [2,9,11] and education in concussion are predictors of superior knowledge.[4,9,11] the respondents in our study were experienced in years of coaching, level of coaching qualification, and boksmart accreditation. there was also a relatively equal representation of the different sizes of schools between the coaches, making for better comparison. the large schools showed the highest percentage (39%) of their coaches between 35-44-years of age, while the small schools have the highest percentage of teachers under 24-years of age (42%). this under 24-year group also represented the highest percentage of coaches without boksmart accreditation (62%) and is the group of coaches with the least qualifications. symptom recognition and concussion knowledge scores it is important to note that similar to international literature, the south african coaches were not aware that emotional symptoms, for example, sadness and irritability, were important symptoms of concussion.[4,8,10] recent research highlights the importance and role of emotional symptoms and the psychological impact that concussion can have on an individual.[8] it is of the utmost importance to realise the significance of these symptoms during the management of concussion and the rtp phase to guard against potential fatal complications of second impact syndrome. the high scores obtained on symptom knowledge (78%) may be attributed to the effectiveness of the ‘recognise and remove’ approach of the boksmart programme. athletic coaches in alabama, united states, scored 87%,[4] and female ice-hockey team coaches in canada scored 88% on similar assessments.[8] regarding the canadian results that tested the knowledge of all role players, coaches scored 81%, only slightly lower than the 85% scored by medical professionals in the same study.[10] the excellent canadian results are testament to the legislated concussion education for high school sports coaches in canada. the general concussion knowledge score of 80% in our study compares well to the scoring in this category in the literature, [8,9] indicating that the tested coaches have a sound knowledge of the recognition of concussion. coaches are aware that the player does not have to lose consciousness to sustain a concussion and they are aware that the player must see a doctor following a concussive incident. however, our group performed poorly when compared to two other studies that asked the same questions [8,2]. only half of the coaches understood that hitting your head was not essential to sustaining a concussion and only 70% knew that concussion symptoms can develop over time. in the literature, most of the respondents from the canadian study answered these two statements correctly.[2,8] researchers in recent years have started more extensive investigations around rtp knowledge of coaches.[1,6,8,10] table 4. summary of statistical significant findings on the influence of independent variables on dependant variables independent (predictor) variable dependent (outcome) variable p-value interpretation coach age group symptom recognition knowledge 0.034 differences in the knowledge of age groups are significant. the 35–44-year age group scored best in all these categories total knowledge score 0.041 size of the school general concussion knowledge 0.0084 large category school coaches have statistically a better general concussion knowledge than small category school coaches boksmart accreditation total knowledge score 0.041 boksmart accredited coaches have superior total knowledge of concussion original research 5 sajsm vol. 34 no.1 2022 previous research investigated rtp knowledge with only a few statements on the category.9 in the literature on rugby union, coaches typically scored worse on their rtp knowledge than in other categories,[1,6] which aligns to the results of the current investigation where coaches only scored 62% on average in the rtp category. welsh elite and semiprofessional coaches scored 71% by comparison,[1] it can be expected that a 62% average result is not indicative of adequate knowledge to make sound decisions on rtp. by comparison, rtp knowledge tested in the same manner in the canadian study revealed an average score of 91%.[10] this score was not only for the coaches as a group, but the average score for all the role players in the management of concussions. it therefore seems possible to improve coaches' knowledge on rtp to a higher level and indicates an opportunity to educate south african high school coaches in this regard. as in canada, the solution might lie in legislated concussion education for sports coaches in south africa. even though the coach as a role player does not make the final decision on rtp, his/her knowledge must be sufficient to ensure player safety. knowledge around concussion rtp by medical professionals might not be up to standard,[12,13] and a coach needs good knowledge on the matter to be comfortable questioning decisions by medical professionals who may return a player to play or training too early. coaches also need to monitor players’ performance after rtp and thereby the lack of knowledge on the value and implementation of cognitive rest during rtp is another significant area of concern that concurs with recommendations from other international studies.[1,4] an average score of 66% for rtp is slightly lower than the scores presented in other research studies. previous studies in rugby union indicated an assessment score of 75% for elite and semi-professional coaches.[1] a total concussion knowledge score of 81%, which includes all three categories, was achieved in the research from canada.[10] the total general concussion scores are difficult to compare with most of the other research, because most of the previous research does not include rtp testing, but only symptom and knowledge testing.[8.4] maddocks questions little is reported in the literature about coach knowledge of the maddocks questions. these are specific questions that should be asked to the player on or next to the field to test their short-term memory and awareness following a potential concussive injury. these questions should be easy to remember, specific, and part of the examination of a concussed player as recommended by the zurich consensus statement in 2012 and the berlin consensus statement in 2016. the group average for the maddocks questions was very low at 26% (1.3/5.0). because of the simplicity of the questions, they should be easy to teach and remember, but it is important to know that the maddocks questions are only a small part of the examination of the concussed player. knowing the answers to the questions does not exclude concussion, but the opposite is more important. if the players do not know the answers, one can suspect that they are concussed and should be removed from the field. preferred sources from which coaches obtain their knowledge the participants’ preferred choices for gaining knowledge about concussion are similar to those described in other studies.[1,8,11] educational programmes and education by healthcare professionals together cover 68% of the first-choice and 63% of the second-choice votes in our study. the third most popular choice was use of the internet. in previous studies, most of the coaches felt that the best source of knowledge was that of the medical professionals with whom they work.[1,8,11] some coaches also thought that a training “kit” is helpful, while some preferred online teaching.[8,11] independent variables age the coaches in the 35-44-year group, significantly outscored the other groups in most of the knowledge categories, including symptom recognition (p=0.034), total knowledge, including maddocks questions (p=0.041). this age group also represents the biggest percentage of coaches at large schools. most of the current literature supports the fact that coaching experience [2,11] and education [4,9,11] are better predictors of knowledge as opposed to only the age of the coach. there was no significant difference in scoring between the coaches according to their qualification levels as a coach and their years in coaching. in both categories there was a trend toward higher scores with experience and higher levels of qualification however, it did not prove to be statistically significant. although not significant, this association does support the notion of coaching experience as a predictor of superior concussion knowledge. [2,9,11] size of school race, socioeconomic circumstances, cost of consultations, household income and geographic location are all predictors of superior knowledge. [10,14] elite high school athletes seem to have better overall concussion knowledge compared to athletes from lower income areas according to studies from america.[14] concurringly, private schools in south africa report more concussions, which may be due to better knowledge and awareness of the risks involved in youth concussions.[15] in south africa, the macro/large schools are typically the schools that can afford to hire professional coaches who are not simply teachers who also coach, and they often have athletic trainers, physiotherapists, and team doctors. the smaller schools on the other hand, are often underprivileged schools with teachers that have to teach, coach, mentor and diagnose concussion. according to our study, the small schools also end up with the non-accredited, youngest, and most inexperienced coaches who scored significantly lower than coaches from larger schools on concussion knowledge in general (p=0.008). that makes this young group of coaches susceptible to unintended mismanagement of concussed players, which may result in career-ending or even fatal injuries. the difference in general concussion knowledge scores being original research sajsm vol. 34 no.1 2022 6 prevalent only in the larger category schools in this study is a reason for concern as it is the hybrid coaches at smaller schools who require better concussion knowledge and related skills. boksmart as can be expected, concussion education is a significant predictor of superior knowledge. [2,4,9] in south africa, concussion education for coaches is provided through the boksmart programme and it is a regulatory requirement of the saru that all coaches are boksmart certified. our results support the notion that education via this educational programme leads to superior knowledge. although the nonaccredited coaches were a small group (n=8), the results confirmed that there is a statistically significant difference in total concussion knowledge between the accredited and nonaccredited coaches (p=0.041). education and legislation through the existing educational channels, such as the boksmart programme in south-africa, can greatly aid in the knowledge and exposure of younger, inexperienced coaches. study limitations and recommendations as with much questionnaire-based research, the response rate was relatively low, with only 143 responses collected from a possible 640. these results can be viewed as a best-case scenario because the responders were also likely to be the coaches with better concussion knowledge and interests in the subject. a factor not investigated in our study is the role of previous personal experience with concussion as a predictor of superior knowledge, particularly since it stands to reason that previous experience with concussions may lead to superior knowledge. although the questionnaire was tested among a small group of coaches from a rugby-playing school, minor layout errors in questionnaire format might also impact the type and quality of answers received by respondents, especially regarding the maddock questions. conclusion this present research undertaking has shown that the participants (high school rugby coaches in south africa) have high general, symptom-specific, and overall concussion knowledge that is comparable to other similar international studies. however, coaches’ knowledge of emotional symptoms, cognitive rest and rtp strategies/management, need to be improved and updated. the age of the coach (mostly in terms of experience), the size of the school and their boksmart accreditation status were significant predictors of superior knowledge related to concussion. smaller category schools, where resources are more limited, have younger coaches that show far lower percentages of boksmart accreditation (required by sa rugby union regulations), lower qualification levels and higher numbers of inexperienced coaches, putting them at a higher risk for unintentional concussion mismanagement and legal repercussions in the event of catastrophic/fatal injuries. future education should aim to address the knowledge gaps specifically regarding cognitive rest, emotional signs and symptoms of concussion and return-to-play management. this can be achieved through an existing educational programme such as boksmart and engagements with healthcare professionals. legislated concussion education for all high school stakeholders, which is the case in canada and the united states of america, can be a possible solution. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: statistical support was given by professor j.h. nel (dsc, pu for cho), department of logistics, stellenbosch university. author contributions: all authors contributed substantially to the research project including: (a) conception, design, analysis, and interpretation of data; (b) drafting / critical revision for important intellectual content; and (c) approval of the version to be published. references 1. mathema p, evans d, moore is, et al. concussed or not? an assessment of concussion experience and knowledge within elite and semiprofessional rugby union. clin j sport med 2016;26(4):320-325. [doi: 10.1097/jsm.0000000000000256] [pmid: 26513391] 2. mrazik m, bawani f, krol al. sport-related concussions: knowledge translation among minor hockey coaches. clin j sport med 2011;21(4):315-319. [doi: 10.1097/jsm.0b013e31821e2b78] [pmid: 21694594] 3. mccrea m, hammeke t, olsen g, et al. unreported concussion in high school football players: implications for prevention. clin j sport med 2004;14(1):13-17 [doi: 10.1097/00042752-20040100000003] [pmid: 14712161] 4. naftel kg, yust em, nichols mh, et al. knowledge and management of sports concussions among coaches and certified athletic trainers in alabama. south med j 2014;107(7):418-423. [doi: 10.14423/smj.0000000000000136] [pmid: 25010582] 5. o’connell e, molloy mg. concussion in rugby: knowledge and attitudes of players. ir j med sci 2016;185(2):521-528. [doi: 10.1007/s11845-015-1313-6] [pmid: 26026952] 6. van vuuren h, welman k, kraak w. concussion knowledge and attitudes amongst community club rugby stakeholders. int j sports sci coach 2020;15(3):297-305. [doi:10.1177/1747954120913175] 7. kroshus e, kerr zy, defeese jd, et al. concussion knowledge and communication behaviors of collegiate wrestling coaches. health comm 2017;32(8):963-969. [doi: 10.1080/10410236.2016.1196417] [pmid: 27462963] 8. guo d, verweel l, reed n. exploring gaps in concussion knowledge and knowledge translation among coaches of youth female hockey. clin j sport med 2017;29(6):486-493 [doi: 10.1097/jsm.0000000000000542] [pmid: 31688180] 9. mcleod tc, schwartz c, bay rc. sport-related concussion misunderstandings among youth coaches. clin j sport med 2007;17(2):140-142. [doi: 10.1097/jsm.0b013e31803212ae] [pmid: 17414483] 10. cusimano md, zhang s, topolovec-vranic j, et al. factors affecting the concussion knowledge of athletes, parents, coaches, and medical professionals. sage open med. 2017;5:2050312117694794.[doi: 10.1177/2050312117694794] [pmid: 24850042] 11. guilmette tj, malia la, mcquiggan md. concussion understanding and management among new england high http://dx.doi.org/10.1097/jsm.0000000000000256 http://dx.doi.org/10.1097/jsm.0b013e31821e2b78 http://dx.doi.org/10.1097/00042752-200401000-00003 http://dx.doi.org/10.1097/00042752-200401000-00003 http://dx.doi.org/10.14423/smj.0000000000000136 http://dx.doi.org/10.1007/s11845-015-1313-6 http://dx.doi.org/10.1007/s11845-015-1313-6 https://doi.org/10.1080/10410236.2016.1196417 http://dx.doi.org/10.1097/jsm.0000000000000542 http://dx.doi.org/10.1097/jsm.0000000000000542 original research 7 sajsm vol. 34 no.1 2022 school football coaches. brain inj 2007;21(10):1039-1047. [doi: 10.1080/02699050701633080] [pmid: 17891566] 12. zemek r, eady k, moreau k, et al. knowledge of paediatric concussion among front-line primary care providers. paediatr child health 2014;19(9):475-480. [doi: 10.1093/pch/19.9.475] [pmid: 25414583] 13. stoller j, carson jd, garel a, et al. do family physicians, emergency department physicians, and pediatricians give consistent sport-related concussion management advice? can fam physician 2014;60(6):548, 550-552. [pmid: 24925947] 14. wallace j, covassin t, moran r. racial disparities in concussion knowledge and symptom recognition in american adolescent athletes. j racial ethn health disparities. 2018;5(1):221-228. [doi:10.1007/s40615-017-0361-1] [pmid: 28389906] 15. shuttleworth-edwards ab, noakes td, radloff se, et al. the comparative incidence of reported concussions presenting for follow-up management in south african rugby union. clin j sport med 2008;18(5):403-409. [doi: 10.1097/jsm.ob013e318181895910] [pmid: 1880654] http://dx.doi.org/10.1080/02699050701633080 http://dx.doi.org/10.1080/02699050701633080 http://dx.doi.org/10.1093/pch/19.9.475 http://dx.doi.org/10.1007/s40615-017-0361-1 sajsm 534.indd sajsm vol. 26 no. 3 2014 81 objective. to determine the attitudes, beliefs and knowledge of talented young athletes residing in gauteng regarding prohibited performance-enhancing drugs (peds) and anti-doping rules and regulations. methods. this was a survey study using a quantitative research approach. south african tukssport academy athletes at the high performance centre, university of pretoria, and competitive high-school athletes at four private high schools in gauteng completed the survey. a selfdetermined, structured questionnaire was used to establish the attitudes, beliefs and knowledge of the athletes. results. a total of 346 (208 males, 138 females) athletes, mean (standard deviation) age 16.9 (1.4) years participated in the survey. according to this survey, 3.9% of the athletes in this survey admitted to using a prohibited ped and more than 14.0% of the athletes said they would consider using a prohibited ped if they knew they would not get caught. ambition (46.0%) and emotional pressure (22.5%) were the primary reasons why the athletes would consider using prohibited peds. even though coaches appeared to be one of the main sources of information (on peds and anti-doping rules), only 42.1% of the athletes felt that they were well informed. conclusion. controlling doping by means of testing is important. however, it may be necessary to put more emphasis on changing attitudes towards doping and implementing additional educational programmes. s afr j sm 2014;26(3):81-86. doi:10.7196/sajsm.542 doping in sport: attitudes, beliefs and knowledge of competitive high-school athletes in gauteng province k nolte,1 phd; b j m steyn,2 dphil; p e krüger,1 phd; l fletcher,3 phd 1 department of physiology, division: biokinetics and sport science, university of pretoria, south africa 2 department of sport and leisure studies, university of pretoria, south africa 3 department of statistics, university of pretoria, south africa corresponding author: k nolte (kim.nolte@up.ac.za) 82 sajsm vol. 26 no. 3 2014 t h e u s e o f p r o h i b i t e d substances and methods is a well-known and complex problem in sport today. [1] the concern is not only in south africa (sa), but is widespread across the world. [2] in sport, the use of prohibited substances or methods to enhance performance is collectively referred to as ‘doping’. it is banned by both national and international sports governing bodies, and the world anti-doping agency (wada), which runs an extensive testing programme and initiatives designed to foster anti-doping attitudes. [3] the main focus in controlling doping has been on testing athletes and the development of tests to detect usage. although athletes’ beliefs and values are known to influence whether or not they will use prohibited performance-enhancing drugs (peds), little is known of their beliefs and attitudes, and the limited empirical literature shows little use of behavioural science frameworks to guide research methodology, results interpretation and intervention implications. [2] furthermore, limited research has focused on this aspect of doping specifically with regard to sa athletes. a study was conducted in 1992 on androgenic anabolic steroid (aas) use in matric pupils in the western cape [4] and more recently gradidge et al. [5] investigated the attitudes and perceptions towards performanceenhancing substance use in johannesburg boys’ high-school sport. therefore, the primary objective of this research was to determine the attitudes, beliefs and knowledge of talented young sa athletes residing in gauteng province regarding prohibited peds and anti-doping rules and regulations. this information may lead to a better understanding of the psychosocial aspect of doping in sport and the development of efficient prevention strategies. methods this was a survey study using a quantitative research approach. ethical clearance for this study was obtained from the postgraduate and ethics committee of the faculty of humanities, university of pretoria, sa. sa tukssport academy athletes at the high performance centre, university of pretoria, and comp etitive hig h-s cho ol athletes from four private high schools in gauteng completed the survey. a self-determined, structured questionnaire was used to establish the attitudes, beliefs and knowledge of the athletes with regards to peds. initially, a pilot study was conducted on 10 academy athletes, after which a few minor adjustments were made to the questionnaire, considering the feedback received from the athletes, in order to ensure that the questionnaire was user friendly and that the athletes understood all the questions. the questionnaire comprised 15 questions along a six-point likert scale. participants signed an informed consent and assent form (parents or guardians signed on behalf of athletes aged <18 years) to participate in the study. participants were given clear instructions on how to complete the questionnaire and anonymity was ensured in order to allow for the participants to answer the questions as openly and honestly as possible. statistical analysis (standard descriptive statistics) was conducted using spss statistics 20 (ibm, usa). results a total of 346 athletes (208 males, 138 females), mean (standard deviation (sd)) age 16.9 (1.4) years, volunteered to participate in the study. the athletes participated in various sports. soccer was the most (28.5%) represented sport from the sample (table 1). more than 32.0% of the participants had been participating in their respective sport for >8 years. results of the questionnaire are presented in table 2. discussion more than 14.0% of the athletes said that they would consider using a prohibited ped if they knew that they would not get caught. this percentage dropped to 9.9% if there was a possibility of being tested and the ped detected. these results confer with the results of bloodworth and mcnamee, [3] who found that a significant minority of british athletes participating in the study entertained the possibility of taking banned hypothetical peds under conditions of guaranteed success and undetectability. therefore, it appears that higher chances of getting caught for using peds by means of successful interventions by relevant authorities, e.g. in and out of competition testing, do act as a deterrent to athletes. however, from our results, almost as many as 10.0% of athletes would still take the risk. waddington et al. [6] found that 73.0% of professional footballers believed that drug testing deterred drug use, and more than half believed that punishments for being caught using a ped or illicit drug were correct. another study, conducted on elite athletes in australia, found that athletes endorsed drug testing as an effective means of deterring drug use. they perceived a difference between being detected using a ped and an illicit drug, and believed that penalties should reflect this difference. [7] thus, effective testing continues to be an important component of anti-doping initiatives. another significant deterrent associated with successful testing is the shame associated with doping. [3] in a review conducted on doping in sport, it was found that initial reasons given for using prohibited peds included a c h i e v e m e nt o f at h l e t i c s u c c e s s b y improving performance, financial gain, improving recover y and prevention of nutritional deficiencies, as well as the idea that others use them, or the ‘false consensus effect’. [1] ambition (46.5%) seemed to be the primar y reason why our sample of sa athletes would take the risk of using prohibited peds, followed by emotional pre s s u re ( 2 2 . 5 % ) an d t h e n f i n an c i a l pressure (11.3%). pressure from parents to excel appeared to contribute substantially to the emotional pressure these athletes feel. therefore, parents should be made aware of the effect this pressure can have on their children. in this study, financial pressure was rated relatively low. however, this is not surprising considering that table 1. participation of the sample in sports sport % soccer cricket swimming hockey athletics golf rugby netball tennis squash table tennis gymnastics other 28.5 10.3 9.2 8.7 8.3 7.1 6.0 5.5 4.4 3.7 3.7 2.1 0.2 sajsm vol. 26 no. 3 2014 83 table 2. attitudes, beliefs and knowledge regarding peds and anti-doping rules and regulations response % q1: i would consider using a legal substance or method, e.g. special diet to improve my sports performance. strongly disagree 15.8 moderately disagree 5.9 slightly disagree 7.3 slightly agree 11.1 moderately agree 20.5 strongly agree 39.0 q2: i would consider using a prohibited substance or method, e.g. anabolic steroids to improve my sports performance, if i knew i would not get caught out. strongly disagree 69.9 moderately disagree 8.5 slightly disagree 6.7 slightly agree 6.7 moderately agree 1.8 strongly agree 6.4 q3: i would consider using a prohibited substance or method to improve my sports performance even if i knew there was a chance that i may get caught out. strongly disagree 80.1 moderately disagree 6.9 slightly disagree 3.0 slightly agree 5.7 moderately agree 2.7 strongly agree 1.5 q4: if you slightly agreed (4), moderately agreed (5) or strongly agreed (6) to question q2 or q3, please state the reason. you may select more than one answer. 4.1 ambition 46.5 4.2 financial pressure 11.3 4.3 emotional pressure 22.5 4.4 other (please specify) 19.7 q5: i currently use a legal substance or method, e.g. nutritional supplement to improve my sports performance. strongly disagree 45.5 moderately disagree 6.0 slightly disagree 3.6 slightly agree 13.5 moderately agree 11.7 strongly agree 19.8 q6: if you slightly agreed (4), moderately agreed (5) or strongly agreed (6) to question q5, please identify the substance or method you currently use. you may select more than one answer. 6.1 dietary supplement 28.9 6.2 specialist advice, e.g. sport scientist or dietician 26.9 6.3 specialist equipment or training techniques 31.7 6.4 other (please specify) 12.4 continued ... 84 sajsm vol. 26 no. 3 2014 table 2. attitudes, beliefs and knowledge regarding peds and anti-doping rules and regulations ... (continued) response % q7: i currently use a prohibited substance or method to improve my sports performance, e.g. anabolic steroids. strongly disagree 90.9 moderately disagree 2.4 slightly disagree 2.7 slightly agree 3.0 moderately agree 0.0 strongly agree 0.9 q8: if you slightly agreed (4), moderately agreed (5) or strongly agreed (6) to question q7, please identify the prohibited substance or method you currently use. you may select more than one answer. 8.1 anabolic steroids 24.2 8.2 diuretics 14.5 8.3 beta-2 agonists 9.7 8.4 blood doping 17.7 8.5 stimulants 17.7 8.6 other 16.1 q9: i am well informed about which substances or methods are prohibited in my sport. strongly disagree 9.1 moderately disagree 6.1 slightly disagree 10.0 slightly agree 12.7 moderately agree 20.0 strongly agree 42.1 q10: from whom do you get your information regarding doping in sport? you may select more than one answer. 10.1 coach 29.7 10.2 other athletes 16.2 10.3 friends 16.5 10.4 parents 19.4 10.5 south african institute for drug-free sport 10.5 10.6 other 7.6 q11: taking prohibited substances or methods is harmful to my health. strongly disagree 6.0 moderately disagree 4.8 slightly disagree 3.9 slightly agree 8.1 moderately agree 15.4 strongly agree 61.7 q12: taking prohibited substances or methods to improve my sports performance is morally wrong. strongly disagree 5.5 moderately disagree 4.6 slightly disagree 5.8 slightly agree 7.6 moderately agree 12.8 strongly agree 63.8 continued ... sajsm vol. 26 no. 3 2014 85 these athletes are still in school and therefore rely on their parents for financial support; this may change when these athletes leave school and become responsible for their own finances. in addition, the reasons could be influenced by the sport that the athlete participates in, as some sports in sa are associated with better financial gain, such as rugby. forty-five per cent of the athletes admitted that they were using a ‘legal’ ergogenic aid. specialist training (31.7%) was rated highest, followed by dietary supplements (28.9%) and specialist advice (26.9%). the use of dietary supplements is widespread at all levels of sport.[8] furthermore, athletes appear to use supplements more than the general population and some take high doses that may lead to nutritional problems. [8] ‘designer supplements’ (over-the-counter supplements containing designer steroids and potent stimulants of which the contaminants are not declared on the label) are a problem in sa. [9] this contamination may, in most cases, be the result of poor manufacturing practice, but there is some evidence of deliberate adulteration of products. [10] there are numerous cases in sa and abroad in which athletes have been tested positive supposedly owing to designer supplements. the continuing story of nutritional supplements and doping infractions has led to a situation where most international sports bodies advise athletes to abstain from using any nutritional supplements. only 3.9% of the athletes who participated in this survey admitted to currently using a prohibited ped. this percentage is low and may not be a true reflection due to the fact that the athletes may have been concerned about the consequences of admitting to using a prohibited ped despite the fact that anonymity was assured. from the athletes who admitted to currently using a prohibited ped, 24.2% said they were using an aas, followed by blood doping (17.7%) and stimulants (17.7%). this was not an unexpected finding since aass are the most widely detected peds in sport. [11] in a survey conducted by alaranta et al. [12] regarding the attitudes of elite athletes towards doping, it was found that stimulants were the most offered substance group (up to 7.0% of all the athletes) followed by aass (4.0%). furthermore, it was found that athletes in different sports have a different approach to doping; the risk of doping appears to be highest in speed and power sports and lowest in motor skills-demanding sports. [12] team-based sports requiring motor skills could be less influenced by doping practices than individual self-paced sports. [3] only 42.1% of the athletes in this study felt that they were well informed about peds and anti-doping rules and regulations. thus, although athletes are becoming increasingly familiar with anti-doping rules, there is still a lack of knowledge that should be remedied using appropriate educational programmes. [1] the participants in this study appeared to get their information primarily from their coach (29.7%), parents (19.4%), friends (16.5%) and other athletes (16.2%). only 10.5% said that they obtain their information from the sa institute for drugfree sport. these results are similar to those in other studies in which it has been found that coaches were the main influence and source of information for athletes. [1] furthermore, as many as 58.7% of the athletes said that not enough is being done to educate athletes regarding table 2. attitudes, beliefs and knowledge regarding peds and anti-doping rules and regulations ... (continued) response % q13: enough is being done in south africa to educate athletes regarding the implications of using prohibited substances or methods. strongly disagree 21.7 moderately disagree 17.4 slightly disagree 19.6 slightly agree 21.4 moderately agree 10.4 strongly agree 9.6 q14: in your opinion, what percentage of elite south african athletes are taking prohibited substances or methods to improve their sports performance? 0 30% 19.3 31 50% 26.6 51 70% 35.8 71 90% 17.7 91 100% 0.6 q15: in your opinion, what percentage of elite athletes world-wide are taking prohibited substances or methods to improve their sports performance? 0 30% 7.8 31 50% 21.1 51 70% 32.4 71 90% 32.1 91 100% 6.5 peds = performance-enhancing drugs. 86 sajsm vol. 26 no. 3 2014 the implications of prohibited ped use in sport. thus, increased efforts to educate athletes as well as coaches regarding the harmful effects of using peds, as well as the ethical or moral concerns surrounding doping, could decrease the likelihood of athletes using peds. one of the major negative aspects of using peds is that they can be harmful to an athlete’s health. in this study, as many as 14.7% of the athletes did not think that doping could have a negative effect on their health. it has been found that athletes who regard doping as a minor health risk seem to be more often associated with doping than those who regard doping as a significant health risk. [12] thus, this is another indication that more education is required with regard to prohibited peds, specifically with regard to the associated health risks. over 63.0% of the athletes strongly agreed that using prohibited peds in sport is morally wrong; however, 15.9% did not have a moral objection to doping. these results are similar to those of a study conducted on british athletes in which the athletes generally embraced those values promoted in anti-doping educational programmes, although there were some notable exceptions.[3] the application of the disconnected values model has recently been proposed to decrease doping in sport. the model is based on the premise that people are more likely to change their behaviour when they acknowledge the disconnect between their actions (negative habits) and their deepest values and beliefs. the primary purpose of the model is to assist athletes in acknowledging that taking drugs, whether for performance-enhancing or recreational purposes, is a negative habit that has benefits, but also dire costs and long-term consequences. [13] a study led by columbia university revealed that some olympic coaches and athletes believe that as many as 90.0% of competitors use peds. [14] in our study, the athletes were asked to indicate what percentage of elite sa athletes, as well as elite athletes worldwide, they think are using prohibited peds, and 51 70% was the highest rated category for both sa athletes and athletes worldwide. these high percentages are concerning, especially if young athletes perceive athletes they admire and look up to as using prohibited peds. studies suggest that professional athletes exert an influence on others, particularly individuals who identify with these athletes. [15] as mentioned previously, one reason why an athlete may decide to use prohibited peds is the idea that others use them – the ‘false consensus effect’. [1] in addition, athletes may also not view using peds as cheating if they are under the impression that most other elite athletes are using prohibited peds to improve their performance. therefore, it is essential that strategies be put in place to change this perception or false consensus effect. conclusion although controlling doping by means of testing is important, it is not sufficient. it is recommended that suitable interventions also be implemented with regard to changing attitudes towards doping and that a greater emphasis be placed on educational programmes, specifically focusing on the health risks of using peds. references 1. morente-sánchez j, zabala m. doping in sport: a review of elite athletes’ attitudes, beliefs and knowledge. sports med 2013;43(6):395-411. [http://dx.doi.org/10.1007/ s40279-013-0037-x] 2. donovan rj, egger g, kapernick v, mendoza j. a conceptual framework for achieving performance enhancing drug compliance in sport. sports med 2002;32(4):269-284. [http://dx.doi.org/10.2165/00007256-200232040-00005] 3. bloodworth a, mcnamee m. clean olympians? doping and anti-doping: the views of talented young british athletes. int j drug policy 2010;21(4):276-282. [http:// dx.doi.org/10.1016/j.drugpo.2009.11.009] 4. schwellnus mp, lambert mi, todd mp, juritz jm. androgenic anabolic steroid use in matric pupils. a survey of prevalence of use in the western cape. s afr med j 1992;82(3):154-158. 5. gradidge p, coopoo y, constantinou d. attitudes and perceptions towards performance-enhancing substance use in johannesburg boys high school sport. s afr sports med 2010;22(2):32-36. 6. waddington i, malcom d, roderick m, naik r. drug use in english professional fo otb a l l. br j sp or ts me d 2005;39(4):e18. [http://dx.doi.org/10.1136/ bjsm.2004.012468] 7. dunn m, tjomas jo, swift w, burns l, mattick p. drug testing in sport: the attitudes and experiences of elite athletes. int j drug policy 2010;21(4):330-332. [http://dx.doi. org/10.1016/j.drugpo.2009.12.005] 8. solbal j, marquart lf. vitamin/mineral supplement use among athletes. a review of the literature. int j sport nutr 1994;4(4):320-334. 9. south african institute for drug-free sport. legislation to push to eradicate ‘designer supplements’. proceedings of the 12 july 2011 supplements in sport symposium, 2011, johannesburg, south africa. 10. maughan rj, king ds, lea t. dietary supplements. j sports sci 2004;25:103-113. [http://dx.doi.org/ 10.1080/0264041031000140581] 11. pandya u. drug abuse in sport. utox update 2002;4(1):1-4. [http://dx.doi. org/10.1080/02640410701607395] 12. alaranta a, alaranta h, holmila j, palmu p, pietilä k, helenius i. self-reported attitudes of elite athletes towards doping: differences between type of sport. int j sports med 2006;27(10):842-846. [http://dx.doi.org/10.1055/s-2005-872969] 13. murphy s. the sport psych handbook. champaign: human kinetics, 2005. 14. sullivan r. this is the olympics on drugs. times magazine (us edition). new york: new york times company, 8 september 2000. 15. quick bl. applying the health belief model to examine news coverage regarding steroids in sports abc, cbs, and nbc between march 1990 and may 2008. j health commun 2010;25:247-257. [http://dx.doi.org/10.1080/10410231003698929] isokinetic neck-sc1-jf-f sajsm vol 17 no. 1 2005 19 introduction the incidence of cervical spinal injuries in rugby and other sporting and recreational activities has been well documented.1, 3, 5, 15, 18, 19, 21-23 cervical spinal injuries that occur during organised team sports are well publicised; however, the majority of serious sports-related spinal injuries occur during unsupervised activities.18 the incidence of cervical spine injuries in rugby has brought about many precautionary measures including rule changes, new policies for selecting players, and conditioning principles.24 however, more players are exposed to potential injury situations due to the changing nature of the game. previously the majority of cervical injuries occurred in the scrum, ruck or maul, involving mainly the forwards.19 increasingly more cervical injuries now occur in the tackle situation,19 exposing the entire team to increased injury risk. a mismatch of physical size and strength between players, combined with differences in skill levels creates a situation conducive to injuries.10 research done in argentine rugby showed that younger players aged between 15 and 21 years were at greater risk of muscle or ligament injuries of the cervical column, which could in turn cause more serious dislocations and/or spinal cord involvement.3 the following cervical spine injury requirements need to be met before the player can return to participation in collision original research article isokinetic neck strength norms for schoolboy rugby forwards d e du toit (dphil) p olivier (ma) l grenfell (ma) b eksteen (ba (hons) biokinetics) department of human movement science, nelson mandela metropolitan university, port elizabeth correspondence: p olivier department of human movement science nelson mandela metropolitan university po box 77000 port elizabeth 6031 tel: 041 504 2497 fax: 041 504 2770 e-mail: pierre.olivier@nmmu.ac.za abstract objective. to generate isokinetic neck strength norms for schoolboy rugby forwards. design. two hundred and eight schoolboys (17.21 – 1.03 years, mean – standard error of the mean (sem), chosen from a population of under-19 first and second xv rugby players, participated in this study. the subjects were assessed anthropometrically and isokinetically according to a set protocol. the isokinetic assessment of neck strength was performed with the use of a specially designed stabilising chair and halo. the subjects performed a single maximal exertion set, consisting of 3 repetitions, through each of the cervical spinal movements in the sagittal and frontal planes. the data were analysed statistically according to positional categories (front-, second-, and back-row forwards), and were used to generate stanine tables of normative data concerning the force characteristics of the cervical spine. results. the front-row forwards produced the largest amounts of force during the measurement of peak torque flexion (ptf = 30.00 – 1.39 nm) and peak torque extension (pte = 55.26 – 1.42 nm). conversely, the second-row forwards performed the best during the measurement of lateral flexion peak torque to the right (ptr = 53.71 – 1.51 nm) and lateral flexion peak torque to the left (ptl = 52.92 – 1.63 nm) in the frontal plane. the front-row forwards were the most powerful in all the neck movements measured (power generated at 0.2 seconds during flexion (powf) = 101.54 – 6.43 w, power generated at 0.2 s during extension (powe) = 167.31 – 8.03 w, power generated at 0.2 s during lateral flexion to the right (powr) = 211.92 – 7.44 w, and power generated at 0.2 s during lateral flexion to the left (powl) = 194.81 – 7.73 w). however, further analysis of the data revealed that few statistically significant differences (p < 0.01 and p < 0.05) existed between the positional categories for the measured variables of peak torque, power generated at 0.2 of a second, peak torque to body mass ratio and cervical range of motion. conclusion. it appears that the various positional categories have not undergone the expected neck strength adaptations to meet the unique requirements of each position. the generation of neck strength normative data allows for the effective and quantified comparison of neck strength variables, enabling more effective injury prevention and rehabilitation. isokinetic neck-sc1-jf-f 5/3/05 8:56 am page 19 20 sajsm vol 17 no. 1 2005 sports; these include possessing normal strength, painless full range of motion, a stable vertebral column and adequate space for the neurological elements.17 while the external forces acting on the sportsman will not decrease, the player must find ways to withstand these forces in order to prevent injury. proper conditioning of the neck musculature is a practical method of injury prevention.5-7, 12, 16, 25 through the course of any contact event the cervical spine is subjected to various forces, which have the potential to cause serious injury. fortunately the spine is protected by the energy-absorbing capabilities of the paravertebral musculature and the intervertebral discs, which effectively dissipate these forces through controlled spinal motion.26 neck strengthening can therefore improve the energy-absorption capabilities of the neck musculature, thus increasing protection of the cervical spine. a comparison between neck muscle strength, efficiency and relaxation times in normal subjects and those with neck pain, found that all force values were significantly lower in those with neck pain.2 several authors11,13,29 have demonstrated that the isometric strength measurement of neck muscles is an objective and practical method of estimating functional improvement in response to rehabilitation. in recent clinical studies9,11,20 intensive strength training of the neck muscles was used as the primary treatment for patients with chronic neck pain. the results of this intervention demonstrated reduced pain intensity and increased neck muscle strength. if cervical conditioning is to be used as an injury prevention and rehabilitation tool, then reliable data must be available to ascertain the condition of a player s neck musculature and its ability to prevent injury. normative data providing information on neck strength characteristics can assist in the identification, prevention, and ultimately the rehabilitation of individuals with poor neck musculature characteristics. similar normative data collected from appropriate population groups (e.g. sedentary and other sporting codes) could be applied in the same fashion. the development of an isokinetic evaluation method assessing spinal movement in the frontal and sagittal planes, allows for reliable and valid measurement of neck strength parameters.6, 7 it has been suggested in the literature that normative data on the strength of the neck musculature in healthy individuals are required for comparative evaluation of patients with neck pain.27 the meaningful application of these isokinetic test results therefore hinges on the availability of normative data from which comparisons and clinical conclusions can be drawn. methodology subjects two hundred and eight subjects with a mean age of 17.21 – 1.03 years were assessed anthropometrically and isokinetically to establish normative data values. the subjects were chosen from a population of under-19 first and second xv rugby players. height and weight were measured prior to the subjects participation in the isokinetic assessment. isokinetic cervical muscular strength testing methods and procedures as proposed by du toit 6 and du toit, et al. 7 were used to examine the force capabilities of the schoolboy rugby forwards neck musculature. torque production was measured through the full range of cervical spinal motion during flexion and extension in the sagittal plane and lateral flexion in the frontal plane (fig. 1). prior to beginning the neck-strength evaluations, informed consent was obtained and participants answered a series of questions that screened for any prior or current cervical spinal injuries that may have precluded a subject from partaking in the study. the evaluation session included a set series of warm-up exercises, viz. active full range of joint motion movements, static stretches, and submaximal isometric contractions. six submaximal warm-up movements were then performed on the isokinetic dynamometer. after completing the 6 submaximal repetitions the subject s head was placed in the neutral position and the range of motion of the dynamometer was reset to zero. when the subject was ready the isokinetic test commenced. isokinetic strength testing was performed at 30…/s. alignment of the dynamometer s input axis corresponded with the vertebral prominence (c7) of the cervical spine. three repetitions of maximal effort through both flexion/extension and lateral flexion to the right and left were recorded and taken as being representative of the neck musculature s peak torque capabilities.6, 7 fig. 1. top: movement pattern in the sagittal plane – extension to flexion. bottom: movement pattern in the frontal plane – lateral flexion to the right and left sides. isokinetic neck-sc1-jf-f 5/7/05 6:48 am page 20 sajsm vol 17 no. 1 2005 21 cervical range of motion testing two cervical range of motion (crom) measurements were taken. the first measurement was taken during the subject s performance of the 3 maximal cervical spinal motions. these crom measurements were labelled maximal voluntary contraction range of motion flexion/extension (mvcrfe) and maximal voluntary contraction range of motion lateral flexion (mvcrlf) respectively. these measurements spanned the whole range of motion from full extension to full flexion and from full lateral flexion right to full lateral flexion left. secondly, these measurements were broken down and represented as separate crom measurements by taking into consideration the anatomical zero. these measurements were labelled maximal voluntary contraction range of motion extension (mvcre), -flexion (mvcrf), -lateral flexion right (mvcrr), and -lateral flexion left (mvcrl). statistical analysis the collected data were analysed and used to create normative data presented in stanine tables. the stanine tables consisted of 3 main categories; poor, average and good. every main category also consisted of 3 subcategories. stanine tables were generated for various measured and calculated variables, namely: peak torque (pt), power generated at 0.2 of a second (pow), crom, and pt ratios. furthermore, one-way analysis of variance (anova) was performed to detect any statistically significant differences for the measured and calculated variables between the various positional categories. hypotheses were tested at the 99% and 95% confidence level. statistical analyses, with the aid of the pearson s moment product correlation coefficient, were also performed to investigate if certain variables were correlated. results and discussion anthropometrical measurements the anthropometrical data are reflected in table i according to the forward positional categories (front, second, and back row). the back-row forwards body mass proved to be significantly less than that of the front (p < 0.01) and second rows (p < 0.05). no significant difference existed between the body masses of the front and second-row forwards. the forwards body masses proved to be significantly positively correlated (p < 0.01) with their height and neck circumference (nc); however, it was not correlated to their neck length (nl). height was significantly positively correlated (p < 0.01) with body mass and nl, however no correlation existed between height and nc. as expected, the second row was significantly taller (p < 0.01) than the front and back rows. the relationship between height and nl may explain why the second row players had significantly longer necks (p < 0.01) than players in the front row. isokinetic measurements peak torque no significant differences (p > 0.05) existed between the positional categories for the measurement of peak torque flexion (ptf), peak torque extension (pte), peak lateral flexion torque to the right (ptr), or peak lateral flexion torque to the left (ptl) (table ii). this result, especially concerning the measurement of pte, seems inconsistent with the function of the front row as well as the forces the front rows are exposed to in the scrum. greater cervical extension strength was expected among the front-row forwards as this would be indicative of their adaptation to the demands of scrummagtable i. descriptive statistics of the schoolboy forwards’ anthropometrical data according to positional categories (n = 208) height (cm) weight (kg) nl (cm) nc (cm) position n mean sem mean sem mean sem mean sem front row 78 174.49* 0.64 85.62* 1.42 15.73* 0.19 39.98* 0.31 second row 52 184.30* 0.58 81.78 1.26 16.68* 0.23 38.93 0.25 back row 78 178.76* 0.66 76.61* 0.89 16.21 0.22 38.34* 0.20 forwards 208 178.54 0.45 81.28 0.75 16.45 0.13 39.09 0.16 * statistically significant difference (p < 0.01) statistically significant difference (p < 0.05). nl= neck length , nc = neck circumference, sem = standard error of the mean. table ii. descriptive statistics of the schoolboy forwards’ peak torque data according to positional categories (n = 208) peak torque (nm) peak torque lateral flexion (nm) flexion (ptf) extension (pte) right (ptr) left (ptl) position n mean sem mean sem mean sem mean sem front row 78 30.00 1.39 55.26 1.42 53.37 1.33 51.35 1.27 second row 52 26.04 1.24 54.69 1.57 53.71 1.51 52.92 1.63 back row 78 28.24 1.12 53.63 1.32 53.38 1.26 51.64 1.36 forwards 208 28.35 0.74 54.51 0.83 53.46 0.78 51.85 0.8 isokinetic neck-sc1-jf-f 5/3/05 8:56 am page 21 22 sajsm vol 17 no. 1 2005 ing. as expected, ptf values were notably lower than those recorded for pte; this was due to the relative size of the musculature involved in the force production during the recorded movements. comparatively, ptr and ptl were very similar due to the bilateral muscular arrangement around the cervical spine. the normative data generated from the collected pt measurements are presented in stanine form in table iii. the maximum and minimum measurements taken for each pt variable by an individual are presented in the best and worst recorded rows. the three main stanine categories, poor , average , and good , are further subdivided. peak torque to body mass ratio descriptive statistics for pt to body mass ratio (pt/bm) are given in table iv. the back-row forwards had the greatest pt (ptf, pte, ptr and ptl) to body mass ratios. the back-row forwards proved to have a significantly higher (p < 0.05) ptf/bm than the second rows. similarly, the back-row forwards proved to have a significantly higher (p < 0.01) ptl/bm than the front rows. as no statistically significant differences existed between the positional categories on the measurements of pt (table ii), the significant differences observed for the pt/bm variables can be attributed to variations in body mass among the positional categories. table i shows that the second-row forwards were significantly heavier (p < 0.05) than the back rows. thus the larger body masses of the second-row players resulted in a decreased and significantly lower (p < 0.05) ptf/bm than that of the back rows. similarly, the front rows proved to be significantly heavier (p < 0.01) than the second-row players, resulting in the significantly lower (p < 0.01) ptl/bm average calculated. thus the observed heavier body masses of the front-row players resulted in the significantly lower (p < 0.01) ptl/bm average calculated. the normative data generated for the pt/bm variable is shown in table v. as can be seen from this table pt/bm values for pte, ptr, and ptl approach 100%. the notable difference between the observed values of pte/bm and ptf/bm is indicative of the variation in muscle mass and arrangement around the cervical spine and consequently the production of pt for the respective movement patterns. likewise the similarity of the ptr/bm and ptl/bm results can also be attributed to the bilateral arrangement of the neck musculature involved in the respective cervical movement patterns. power generated at 0.2 of a second descriptive statistics (table vi) of the power generated at 0.2 of a second (pow) variable, measured in watts, revealed that the front-row forwards were best in all movement patterns. however, the numerical advantage translated into only 1 statistically significant difference. front-row forwards proved to table iv. descriptive statistics of the schoolboy forwards’ peak torque to body mass data according to positional categories (n = 208) peak torque to body mass ratio (%) ptf/bm pte/bm ptr/bm ptl/bm position n mean sem mean sem mean sem mean sem front row 78 35.19 0.02 65.11 0.02 63.12 0.02 60.74 0.02 second row 52 31.62* 0.02 67.25 0.02 65.77 0.02 64.94 0.02 back row 78 37.09* 0.01 70.20 0.02 69.88 0.02 67.51 0.02 forwards 208 35.01 0.01 67.55 0.01 66.32 0.01 64.33 0.01 * statistically significant difference (p < 0.05). statistically significant difference (p < 0.01) table v. stanine table of normative data for peak torque to body mass ratio (n = 208) peak torque to body mass ratio (%) extremes and extension flexion right-flexion left-flexion stanine categories worst recorded 32 12 28 20 1. extremely poor 0 44 0 17 0 44 0 38 2. very poor 45 50 18 20 45 49 39 47 3. poor 51 56 21 25 50 56 48 57 4. below average 57 62 26 30 57 60 58 61 5. average 63 70 31 36 61 69 62 66 6. above average 71 76 37 41 70 77 67 74 7. good 77 87 42 50 78 84 75 84 8. very good 88 92 51 61 85 91 85 90 9. excellent 93 + 62 + 92 + 91 + best recorded 113 81 103 103 table iii. stanine table of normative data for peak torque (n = 208) peak torque (nm) extremes and extension flexion right-flexion left-flexion stanine categories worst recorded 28 9 24 14 1. extremely poor 0 32 0 12 0 -33 0 28 2. very poor 33 39 13 15 34 41 29 37 3. poor 40 44 16 19 42 45 38 43 4. below average 45 50 20 25 46 49 44 49 5. average 51 55 26 29 50 53 50 52 6. above average 56 63 30 34 54 60 53 59 7. good 64 70 35 42 61 66 60 65 8. very good 71 77 43 51 67 72 66 71 9. excellent 78 + 52 + 73 + 72 + best recorded 87 72 89 80 isokinetic neck-sc1-jf-f 5/3/05 8:56 am page 22 sajsm vol 17 no. 1 2005 23 be significantly more powerful (p < 0.01) than the back-row players on the measurement of flexion power generated at 0.2 of second (powf). however, it was expected that the front-row players would be significantly stronger (table ii) and more powerful (table vi) than the other positional categories. this would have been an indication of their adaptation to the demands of their position within the tight scrum. the normative data for the power generated at 0.2 of a second variables are shown in table vii. the data again show that the measurements made through the extension, lateral flexion right, and lateral flexion left movement patterns are fairly similar. peak torque ratios the normative data represented in table viii show the muscle strength ratios of the agonist to antagonist for each specific movement pattern of the cervical spine assessed. as discussed previously, extension strength due to the muscle mass involved in the movement is much greater than that of flexion strength. this table illustrates that low ratios are rated as poor or below average (0 39%). this is seen by the optimal ratio between ptf and pte being approximately 49 53%. normative data concerning the ratio of cervical flexion to extension strength in the normal population suggest that a ratio of around 60% is optimal.8 however among rugby forwards stronger cervical extensors are preferable as they will enable the player to resist the forces experienced in the tight scrum. conversely, the bilateral symmetry of the musculature producing lateral flexion left and right predicts the optimal ratio for ptr to ptl to be 100%. these low ratios (table viii) can be attributed, in the case of ptf/pte, to weak cervical flexors; conversely, too high a ratio (table viii) is also interpreted as poor or below average and indicative of weak cervical extensors. this principle is also applied in the reflection of ptr/ptl normative data. cervical range of motion no statistically significant differences were observed between the positional categories during the measurement of crom (table ix). the average mvcrfe during the flexion movement pattern was 118.15ß. the mean values were 58.63ß from full extension to neutral (anatomical zero) and 58.91ß from neutral to full flexion. during the extension movement pattern a larger mvcrfe was measured (125.79ß). the mean values were 62.66ß from full flexion to neutral and 64.12ß from neutral to full extension. these values correspond well with other measurements reported in the literature. buck et al.4 reported values of 66ß – 8ß for flexion and 73ß – 9ß for extension in a sample of young males. lind et al.14 only reported a total average flexion and extension of 68ß – 26ß. wolfenberger et al.28 established the mean crom for flexion/extension, with the use of radiography, to be 108… in a sample (n = 39) of 20 29-year-old males. dual inclinometry delivered a value of 101…, and with a bubble table vi. descriptive statistics of the schoolboy forwards’ power generated at 0.2 of a second data according to positional categories (n = 208) power generated at 0.2 of a second (w) powf powe powr powl position n mean sem mean sem mean sem mean sem front row 78 101.54* 6.43 167.31 8.03 211.92 7.44 194.81 7.73 second row 52 72.40 5.60 161.15 7.01 206.63 8.54 184.42 9.16 back row 78 69.17* 5.21 150.19 8.24 189.42 8.64 178.08 9.14 forwards 208 82.12 3.55 156.35 4.66 202.16 4.81 185.94 5.04 *= statistically significant difference (p < 0.01). table vii. stanine table of normative data for power generated at 0.2 of a second (n = 208) extremes and stanine power generated at 0.2 of a second (watts) categories extension flexion right-flexion left-flexion worst recorded 19 5 25 23 1. extremely poor 0 25 0 10 0 70 0 50 2. very poor 26 60 11 20 71 105 51 80 3. poor 61 95 21 40 106 140 81 120 4. below average 96 125 41 55 141 160 121 160 5. average 126 160 56 80 161 220 161 205 6. above average 161 205 81 115 221 250 206 230 7. good 206 240 116 150 251 275 231 260 8. very good 241 275 151 210 276 320 261 310 9. excellent 276 + 211 + 321 + 311 + best recorded 350 300 360 355 table viii. stanine table of normative data for peak torque ratios (n = 208) ratio (% actual) extremes and flexion extension right left stanine categories low high low high worst recorded 19 100 35 143 1. extremely poor 0 11 95 + 0 68 132 + 2. very poor 12 25 81 94 69 76 124 131 3. poor 26 32 74 80 77 83 117 123 4. below average 33 39 67 73 84 87 113 116 5. average 40 43 63 66 88 92 108 112 6. above average 44 48 58 62 93 95 105 107 7. good 49 51 55 57 96 97 103 104 8. very good 52 52 54 54 98 99 101 102 9. excellent 53 53 53 53 100 100 best recorded 53 53 100 100 isokinetic neck-sc1-jf-f 5/3/05 8:56 am page 23 goniometer 100… of crom for flexion/extension was obtained.28 similar results were observed for the measurement of lateral flexion left and right crom. however, the obtained results were smaller than those seen with the measurement of mvcrfe. the average mvcrlf to the left was 111.39ß, and during lateral flexion to the right an average of 111.75ß was recorded. the mean values were 53.8ß from neutral to full lateral flexion right and 56.14ß (average) from neutral to full lateral flexion to the left. lind et al.14 reported slightly lower averages for both lateral flexion left and right crom with a value of 45ß – 14ß. active crom for lateral flexion left to right, measured with a goniometer, for a sample (n = 20) of males aged from 11 to 19 years was calculated to be 91.1ß.30 the normative data represented in stanine format in tables x and xi show complete crom measurements through the full range of cervical motion in the sagittal (mvcrfe) and frontal (mvcrlf) planes. the results show that the various positional categories do not appear to have undergone the expected specific neck musculature adaptations to meet the unique requirements of each position. this may be due to the lack of education of players and coaches on the importance of proper neck musculature condition for safe participation in rugby. this naturally leads to little time and effort spent by coaches and players on specific conditioning of the neck muscles resulting in underdeveloped and weak neck muscles. furthermore, in conjunction with poor or insufficient conditioning of the neck muscles, players of the age investigated in this study possibly have not yet been exposed to sufficient bouts of cervical spinal exertion in the tight scrum to have undergone the needed adaptations. this is, however, more reason to encourage neck musculature conditioning. conclusion the generation of normative data pertaining to the force characteristics of the neck musculature can be usefully applied as an injury prevention and rehabilitative tool. by identifying weak musculature in players prior to participation possible injury can be avoided. the usefulness of this method of assessment is not only limited to the sporting individual; the general population can also benefit from neck musculature conditioning to prevent or rehabilitate the painful cervical spine. references 1. armour ks, clatworthy bj, bean ar, wells je, clarke am. spinal injuries in new zealand rugby and rugby league — a twenty year survey. n z med j 1997; 110: 462-5. 2. barton pm, hayes kc. neck flexor muscle strength, efficiency, and relaxation times in normal subjects and subjects with unilateral neck pain and headache. arch phys med rehabil 1996; 77: 680-7. 3. bottini e, poggi ejt, luzuriaga f, secin fp. incidence and nature of the most common rugby injuries sustained in argentina (1991 1997). br j sports med 2000; 34: 94-7. 24 sajsm vol 17 no. 1 2005 table x. stanine table of normative data for cervical range of motion (n = 208) extremes and stanine range of motion – mvcrfe & mvcrlf (deg) categories extension flexion right-flexion left-flexion worst recorded 87 76 70 73 1. extremely poor 0 96 0 87 0 86 0 88 2. very poor 97 103 88 97 87 94 89 94 3. poor 104 111 98 104 95 103 95 102 4. below average 112 119 105 114 104 107 103 108 5. average 120 131 115 122 108 114 109 113 6. above average 132 138 123 133 115 121 114 120 7. good 139 144 134 141 122 125 121 125 8. very good 145 149 142 145 126 131 126 132 9. excellent 150 + 146 + 132 + 133 + best recorded 159 172 143 140 table xi. stanine table of normative data for cervical range of motion (n = 208) extremes and range of motion – mvcre, mvcrf, stanine mvcrr & mvcrl (deg) categories extension flexion right-flexion left-flexion worst recorded 20 15 34 29 1. extremely poor 0 28 0 26 0 42 0 32 2. very poor 29 43 27 37 43 47 33 40 3. poor 44 50 38 44 48 50 41 44 4. below average 51 57 45 53 51 55 45 49 5. average 58 66 54 62 56 58 50 55 6. above average 67 75 63 70 59 62 56 58 7. good 76 80 71 78 63 67 59 64 8. very good 81 87 79 83 68 71 65 69 9. excellent 88 + 84 + 72 + 70 + best recorded 93 87 78 73 table ix. descriptive statistics of the schoolboy forwards’ cervical range of motion data according to positional categories (n = 208) range of motion mvcrfe & mvcrlf (deg.) flexion extension right – flexion left flexion position n mean sem mean sem mean sem mean sem front row 78 117.19 1.8 123.29 1.74 109.54 1.43 109.46 1.38 second row 52 120.02 2.48 129.64 2.27 113.62 1.65 113.85 1.69 back row 78 117.86 1.99 126.04 1.85 112.71 1.29 111.68 1.33 forwards 208 118.15 1.18 125.76 1.11 111.75 0.84 111.39 0.84 isokinetic neck-sc1-jf-f 5/3/05 8:56 am page 24 26 sajsm vol 17 no. 1 2005 4. buck ca dameron fb, dow mj, skowlund hv. study of normal range of motion in the neck 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rc. head and neck injuries in young athletes. clin sports med 2000; 19: 693 715. 19. quarrie kl, cantu rc, chalmers dj. rugby union injuries to the cervical spine and spinal cord. sports med 2002; 32: 633-53. 20. randl¿v a, fl stergaard m, manniche c, et al. intensive dynamic training for females with chronic neck/shoulder pain. a randomized controlled trial. clin rehabil 1998; 12:200 -10. 21. rotem tr, lawson js, wilson sf, engel s, rutkowski sb, aisbett cw. severe cervical cord injuries related to rugby union and league football in new south wales, 1984 1996. med j aust 1998; 168: 379-81. 22. scher at. rugby injuries to the cervical spine and spinal cord — a 10-year review. clin sports med 1998; 17: 165-206. 23. secin fp, poggi ejt, luzuriaga f, laffaye ha. disabling injuries of the cervical spine in argentine rugby over the last 20 years. br j sports med 1999; 33: 33-6. 24. silver jr. the impact of the 21st century on rugby injuries. spinal cord 2002; 40: 552-9. 25. torg js. 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72: 770-80. isokinetic neck-sc1-jf-f 5/3/05 8:56 am page 26 original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license factors promoting and hindering sporting success among south african former olympians from historically disadvantaged areas s mthombeni, phd; y coopoo, dphil (facsm); h noorbhai, phd department of sport and movement studies, faculty of health sciences, university of johannesburg, johannesburg, south africa corresponding author: s mthombeni (smthombeni.solly@gmail.com) international sporting success in any nation is centred on achieving international prestige, socioeconomic development, and enhancement of national pride, to name a few. therefore, increasing competitiveness for sporting success encouraged global investments towards elite sports policies among nations to facilitate elite sport development through a uniform model. more importantly, the success of an individual athlete or team is dependent on the national system's performance capacity and its effectiveness in the usage of resources toward elite sporting success. [1] de bosscher et al. [1] developed a conceptual framework of sport policy factors leading to sport success (spliss) that would be used as a model for nations to assess sporting success. the spliss model consists of nine pillars including financial resources, governance, organisation and sport policy, foundation level participation, identification and development of talent, post-sport career support, provision for sports infrastructure, provision for coaching and development, access to national and international competitions, as well as scientific research and support. [1] de bosscher et al. [1] used the mixed methods approach for spliss to compare policies of elite sport among 15 countries and indicated that the composite indicators were helpful in the identification of a relationship or non-relationship between sports policies and success, facilitation of comparison and interpretation of counties, as well as the understanding of differences in elite sport systems. mazzei et al. [2] evaluated the structure of the brazilian high performance sports policies through the spliss framework and found the existence of financial resources, but a lack of strategic planning and integration of the sports policies, leading to ineffective management of the application of resources. therefore, more financial resource allocations towards high performance sport does not necessarily lead to a better international performance in sport if the other pillars of support are not well structured. a better synergy between the pillars of support is necessary for international sporting success. [2] in the south african context, sport played a central role in transforming south africa by creating a post-apartheid identity that was aimed at eliminating divisions on a basis of race, gender, class, and geographical location. [3] apartheid was a south african policy and ideology of racial segregation. [3] the national sport and recreation plan (nsrp) [4] highlighted that the system of apartheid led to gross inequality, whereby over 50% of the south african population, which were predominantly black africans, lived below the poverty line. this led to inequalities and an uneven playing field within the sports sector. [4] the post-apartheid government elected in 1994 developed the new department of sport and recreation south africa (srsa), now referred to as the department of sport, arts, and culture (dsac), as the government department the mandate of which was, largely, to address the injustices of the past by ensuring equality in the field of sport and establishing the transformation charter. [4] coetzee et al. [5] reported that racial inequalities in sports from the apartheid era continue to affect sports participation or non-participation on a basis of race, across various sporting codes in south africa, as different opportunities for most sports are still not accessible for the black population. desai [6] argues that although the sport of swimming in south africa, for instance, continues to claim global dominance in terms of competitiveness, it is still primarily regarded as a ‘white’ sport as it remains dominated by swimmers from the white community, more especially at the highest level of competition. this is a consequence of the sport infrastructure (especially swimming facilities) being historically concentrated in the recreational and residential areas of the white community during apartheid, and which were legislated to only be used by the white population. recreational facilities, including functional swimming facilities were inadequate or non-existent in the predominantly black townships and the effects continued to be felt in post-apartheid there are various contributing factors to sporting success among elite athletes, including olympians. the purpose of this paper was to investigate the enablers and/or barriers to sporting success among south african former olympians from historically disadvantaged areas (hdas) using the spliss framework. this would enable an understanding of the factors that lead to sporting success among athletes from hdas. a qualitative research design was employed for this study, whereby semi-structured interviews were conducted among 15 former olympians who represented south africa between the 1992 and 2016 olympic games. the atlas.ti (version 22) software tool was used to analyse the data. the study found that athletes from hdas attributed their sporting success to the functional competition structure, sports access at community level, access to scholarships and bursaries to elite schools/universities, good coaching support and mentorship, access to local and international competitions, as well as community and peer athlete support. the highest barriers reported by athletes were inadequate financial support, a dysfunctional school sport system, lack of sports facilities, equipment and transport system, poor post-career and scientific support. elite athletes from hdas need consistent financial support, school/foundation level sport access, quality sports facilities, equipment, and reliable transport to training and competitions, post-career, as well as scientific support to achieve their full potential and attain international sporting success. keywords: support systems, historically disadvantaged areas, olympics, athletes s afr j sports med 2023;35:1-9. doi: 10.17159/2078-516x/2023/v35i1a15068 mailto:smthombeni.solly@gmail.com http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15068 https://orcid.org/0000-0001-9464-6854 https://orcid.org/0000-0001-9865-3031 https://orcid.org/0000-0001-5148-1607 original research sajsm vol. 35 no.1 2023 2 south africa, making it almost impossible to nurture talent from the black townships. [6] the transformation charter defines transformation as a process of changing the delivery of sport holistically through the actions of individuals and organisations to harness the socioeconomic benefits of sport. the charter aimed at increasing access and opportunities in sport and recreation for all citizens, with particular emphasis on previously disadvantaged groups, including but not limited to, black (i.e. african, coloured, and indian) population groups which included, women, children, youth, persons with disabilities, as well as the elderly. [5] therefore, historically disadvantaged areas (hdas) in this study referred to areas that were underfunded and underdeveloped during the apartheid era, whereby the legacy of underdevelopment persists to date. these areas include townships, farms, and rural areas (as well as villages). [7] xaba and malindi [7] highlight hdas as historical settlements characterised by poor socioeconomic conditions, including poor infrastructure development, and most were designated as living areas for black people. dove et al. [8] investigated career progression to the elite level among black south african cricket players and found that game exposure, coaching, facilities and equipment, education, and support networks as enablers of success, and poor socioeconomic factors, development pathways, team environment and leadership were barriers to success. this required a need to further investigate whether other sporting codes, or sport in general, has similar enablers and barriers to success in south africa, thus necessitating a need for further insight into potential success factors and barriers to sporting success, with a particular emphasis on athletes from hdas. the most important research questions for this study were as follows: do the current systems of sport support in south africa create an enabling environment for an athlete to achieve international success? if so, what are these enabling factors, and if not, what are the hindrances? sport in south africa is under the responsibility of the national department of sport, arts, and culture (dsac), which has mandated the south african sports federation and olympic committee (sascoc), along with the national sports federations (nsfs) to deliver high performance sport in south africa to all. tertiary institutions, sports academies, and professional sports clubs are structures that also form part of the pathway for elite athletes to reach high performance in sports. [4] the figure above shows a typical distribution mechanism for the delivery of high performance sports in south africa. figure 1 illustrates the south african support mechanism for high performance sport. the purpose of the paper is to investigate the enablers and/or barriers to sporting success among south african former olympians from hdas using the spliss framework. this would enable an understanding of the factors that lead to sporting success among athletes from hdas, and overcoming barriers to sport participation. methods study design and participants a qualitative research design was employed for this study. a total of 15 athletes (13 males and 2 females) participated in semi-structured interviews as part of the study procedure (table 1). the participants in the study were athletes that have represented south africa at the olympic games between 1996 and 2016. the participants were current and retired south african athletes that were born and had resided in hdas at some stage of their sporting careers. the participants were all black african former olympians between the ages of 29 and 50 years, of which nine were still active athletes and six had retired from their sport. the sporting codes represented included: athletics (n=7), rugby sevens (n=2), boxing (n=2), football (n=1), canoeing (n=1), hockey (n=1), and sailing (n=1). ethical considerations the faculty of health sciences research ethics committee at the university of johannesburg provided ethical approval for the study (rec-500-2020). the participants provided consent prior to participating in the study. data collection the interviews were conducted telephonically and audiotaped. a portable tablet voice recorder (lenovo tab m10 hd, slovakia) was used for the recording of the interviews with participants. the interviews were, on average, 38 minutes in duration. a step-by-step interview guide was used to ensure that the interviews occurred similarly and systematically. all nine interview questions were open-ended and were in line fig. 1. south african support mechanism for high performance sport [4] high performance sport south african sports confederation and olympics committee (sascoc) national department of sport, arts, and culture national sport federations sports academies & tertiary institutions club system original research 3 sajsm vol. 35 no.1 2023 with the spliss framework, with questions investigating enablers in, as well as barriers to, elite sport participation under the following themes; access to financial resources; governance, organisation, sports policies, access to competitions; opportunities for sport participation at foundation level; talent scouting and development; post-career support; access to sports facilities; access to coach support and development; access to international competitions; and access to scientific support (table 2). follow-up questions were also conducted to allow participants to provide further insight into the matters discussed. data analysis the interview data were translated from the audio recorder and transferred to a laptop for storage and analysis. the audio data were then transcribed manually and through a computer software known as otter.ai (los altos, california, us) into text format by the interviewer. upon the conclusion of the transcribing, all the text captured in the native language of the participants was translated into english. familiarisation of the data was conducted to understand the breadth and depth of the content. a thematic analysis approach was employed. the initial codes were formed based on the interesting concepts to analyse. from the initial codes, a total of 42 meaningful themes that highlighted the athletes’ career pathways and experiences were identified. the themes were then categorised into 11 factors of sport support. from the 11 factors of sport support, six enablers and five barriers to sporting success were identified, followed by the write-up of the findings. the atlas.ti (version 22) software tool was used to analyse the data. results and discussion the results of the study found that factors that enabled sporting success among athletes from hdas were functional sport structures, access to community sport, bursaries and scholarships, coaching support and mentorship, local and international competitions, as well as community and peer support. factors that were found to hinder sporting success among athletes from hdas were lack of financial support, a dysfunctional school sport system, lack of facilities and equipment, lack of post-career support, and poor scientific support. table 1. participant demographics participant gender race age (years) sport number of years of involvement a1 male black 47 athletics track 37 a2 male black 50 athletic marathon 28 a3 male black 48 athletics track 32 a4 male black 45 athletic marathon 32 a5 male black 37 athletic marathon 21 a6 female black 39 athletic marathon 33 a7 male black 47 athletic marathon 29 a8 male black 30 boxing 18 a9 male black 44 boxing 37 a10 male black 32 rugby sevens 20 a11 male black 29 rugby sevens 19 a12 female black 34 soccer 24 a13 male black 38 canoeing 27 a14 male black 30 sailing 19 a15 male black 38 hockey 25 table 2. explanatory notes for the nine pillars used in the questionnaire pillar explanatory notes for the pillar 1. financial resources this includes financial resource assistance in the form of grants (from government, federations, ngos, sponsorships, etc.). 2. organisation and the structure of sport policies refers to the availability and access to the sport competition system at all levels, including local, provincial and national level. 3. foundation and participation refers to the accessibility and participation of the sport code at foundation phase (i.e. school competition system, youth club/development academy, etc.). 4. talent identification and development system refers to the systems in place to identify and develop sporting talent (i.e. talent scouting, sport career pathing, etc.). 5. post-career support refers to support provided to athletes upon retirement from their sport (scholarships and bursaries, life skills, career/job prospects, mentoring opportunities, volunteerism, etc.) or any other opportunity to make a living after sport. 6. sports training facilities refers to the availability of sports facilities that athletes have access to. 7. coach provision and development refers to availability and access to qualified/experienced coaches. 8. local and international competitions refers to availability and access to local and international competitions where athletes can compete and showcase their talent. 9. scientific support refers to availability and access to scientific support programmes for the athlete (i.e. sports medicine/science, evidence-based programmes and research, nutrition, sports psychology, high performance, match/performance analysis, etc.). sourced from sport policy factors leading to sport success (spliss) framework [1] original research sajsm vol. 35 no.1 2023 4 enablers functional sport structures when asked about governance, organisation and sport policy, the majority of athletes reported that south africa has functional sports structures which provide an enabling environment to compete in sport from local, progressing to regional, provincial and national championships. international colours were provided to them when performing well at a national level. the athletes also reported that there are sufficient local league competitions for them to compete in and gain recognition (figure 2). one commented as follows: ‘we would compete in teams around our region, then provincial, then to national. the structures of competition and league system are good.’ (athlete 9) the availability of governance, organisation and structure of sport policy was supported by jacobs, de bosscher, and venter [9] who also reported on the availability of national, provincial, and local sports structures (government departments, local municipalities, and federations), all of which administer sport in south africa as guided by the national white paper on sport and recreation. however, it has been highlighted that interorganisational relationships between governmental sport stakeholders need to be further strengthened to allow for the understanding of the different roles and responsibilities that each entity needs to play in the field of sport. this will ensure that there’s no duplication of roles and the effectiveness of the delivery of sport programmes is improved (jacobs, de bosscher, and venter. [9]). functional sport structures allow for athletes to compete regularly, and in a coordinated manner that allows those that are more talented to progress through the competition ranks from local to national, and eventually international level. access to community sport the majority of athletes reported that one of the important factors that enabled them to participate in their respective sporting codes was that it was accessible within their community from a young age. it was reported that they participated in their local community sports clubs which offered the sport at a social and competitive level. however, most of the athletes also indicated that the sport was not accessible at the school level as their schools did not offer any structured sports programme. few athletes had access to their sport at the school they attended, but they were able to attend well-resourced schools in suburban areas, not within their communities. most of these opportunities came in the form of sports and academic scholarships. one was quoted as follows: ‘…but for us in our community, the sport of canoeing was the main sport due to our proximity of the river nearby’ (athlete 14) this finding was similar to that of dove et al. [8] who found that early exposure to sport is one of the enabling factors for cricket success among south african black cricketers from townships and rural areas. this presents a challenge for south africa, as physical education in predominantly disadvantaged schools does not form part of the curriculum and is merely seen as a voluntary extracurricular activity. therefore, in most cases, athletes have to rely on volunteer-based local community sports clubs to get exposure and participation in sport. attending wealthier elite semi-private or private schools with sufficient sporting infrastructure and support also comes with a distinct advantage as they serve as a feeder system for professional and national teams. [10] noorbhai [10] found that the majority of the south african cricketers who played for the national team (the proteas), mostly attended the wealthy elite and boys-only schools, irrespective of race. so in essence, athletes from hdas who are unable to receive scholarships from these elite schools, may have to rely on local community sport clubs to navigate through sport, which in most cases, may be a more difficult route for the athlete, as most of the clubs may not be part of the feeder system to professional or national teams if cricket was used as an example. in the absence of physical education in low income schools, more local community-based clubs have to be established, and receive financial incentives from the government and the national lottery for developing athletes in the townships. this may indicate that government may need to reprioritise its spending and consider funding township-based sports clubs based on how many athletes they develop, more especially in unpopular sporting codes. bursaries and scholarships all the athletes in this study reported being offered and provided with sports bursaries and scholarships by universities at some point in their sporting careers as part of their postcareer support. scholarships and bursaries in this study were two-fold, with some athletes provided with sports and academic scholarships to attend elite former model c schools (previous and current well-resourced semi-private public sporting success among athletes from hdas enablers functional sport structures access to community sport bursaries and scholarships coaching support and mentorship local and international competitions community and peer support barriers lack of financial support dysfunctional school sport system lack of sports facilities and equipment lack of post-career support poor scientific support fig. 2. results showing the perceived enablers and barriers in south african sport by athletes original research 5 sajsm vol. 35 no.1 2023 schools for the wealthier elite population group) in town, as well as university sports bursaries to fund their tertiary education studies. the bursaries not only allowed them to have access to education but also allowed them to be able to afford the necessities they needed for their sport (i.e. accommodation, sports attire, equipment, and nutrition). athletes that went to former model c schools on scholarships had access to good sports infrastructure, school accommodation, nutrition, coaching and mentorship, and other support structures from an early age. however, to have access to such bursaries, they also needed to produce satisfactory academic results for admission into these elite schools or universities. one commented as follows: ‘there were also opportunities for me as a senior athlete to have access to sports bursaries.’ (athlete 4) the findings are supported by thompson, rongen, cowburn, and till, [11] who found that scholar athletes from sportfocused schools receive considerably more support in terms of academics, high-level training and competitions, recognition systems, and prospects of higher education continuation. these support systems positively contribute to the athletes’ long-term holistic development and success as an athlete when compared to their peer athletes who attended non-sport schools. universities in south africa offer varsity sports tournaments in most sporting codes. these tournaments serve as catalysts for student athletes to access high-level competition, financial and non-financial incentives and rewards, social well-being, as well as the promotion of their sporting career [12]. this indicates that universities may present athletes from hdas with opportunities for participation in sports that may not be available in the communities where they grew up. bursaries also provide an opportunity for personal development of these athletes. coaching support and mentorship the majority of athletes had access to coaching support from development (early age) until a high performance level. the athletes reported that although most of their developmental coaches were community volunteers, they all had the appropriate knowledge, skills, and coaching experience within the sport. most athletes also highlighted that their coaches were their greatest mentors that propelled them toward sporting success. one profound comment was as follows: ‘…one thing that made him stand out was that he understood where we came from as players, he knew that we came from underresourced communities, so what made the relationship good was that he was able to mentor us despite the difficulties that we faced before in life.’ (athlete 11). trzaskoma-bicsérdy et al. [13] highlight that the nature of an athlete-coach relationship is more likely to determine the athlete’s performance, self-esteem, and satisfaction. when a coach can create an environment that fuels inspiration to the athlete and emphasises effort, the athlete is then able to positively respond by striving for excellence [13] athletes in hdas need to have access to an inspirational coach who is fully committed to supporting the athlete, both on and off the field of play. at times, athletes may lack parental figures who can provide moral support when playing sports, and the coach is therefore compelled to fill this important role. hallmann, breuer, and beermann [14] defined a mentor as an experienced or high-ranking member in society or an organisation forming a relationship by coaching, advocating, and sponsoring the development of a less experienced mentee. benefits of mentorship include increased personal development, satisfaction, self-worth, reputation and required skills, all of which are important for athletic success. [14] therefore, it is important for coaching training and development programmes at federation level to include courses on mentorship and athlete welfare, so that they know how to provide the best possible support for their athletes. local and international competitions the majority of athletes reported that some of their enablers towards sporting success included access to managers, agents, and professional clubs, which negotiated on their behalf and assisted them to compete internationally and gain international recognition. some athletes also highlighted that the local competition structure was so highly competitive that it adequately prepared them for international success. some commented as follows: ‘i did have access to international competitions.’ ‘the more events that you compete in and win internationally, the more opportunities come to you to compete internationally.’ (athlete 4) ‘our competition system here in sa is good and there are enough competitions in the country, whether you have a sponsor or no sponsor.’ (athlete 3) ferguson [15] highlights that constant competitions, effective coaching, and access to appropriate sports facilities are among the most important factors for elite sporting performance and the success of nations. it is important, however, for athletes to have access to sufficient competitions from an early age as they progress in sporting performance and maturity. it is also important for south african national federations to produce quality local competition structures to enable athletes to progress through the competitive ranks, aiming for international success. ferguson [15] further reiterates that highquality local competitions allow athletes to test themselves against local competitors, and adequately prepares them for international success. de bosscher, du bois, and heyndeld [16] reported that an increase and exposure to the international competition environment increases competitiveness in athletes, and subsequently improvement in athletic performance. this, therefore, suggests that as athletes become more exposed to international competitions and compete at a higher intensity, they are more inclined to improve in their competitiveness and experience. community and peer support the majority of athletes indicated that one of their enablers for sporting success was the support they received from their communities, including friends, family, community leaders, sports legends from their communities, as well as educators, all original research sajsm vol. 35 no.1 2023 6 of whom were their key motivators. they also highlighted that it was through the volunteers and coaches within their communities who established local sports clubs, that enabled them to start participating in sports. athletes also highlighted the importance of peer-athlete support in terms of learning and sharing of ideas on training regimes and techniques, sharing of sports equipment/attire and transport to competitions, as well as moral support being the important contributors of their success in sport. one commented as follows: ‘there was a lot of support from my fellow boxers, including my brother, which played an important role in creating an environment for me to excel in the sport and become successful.’ (athlete 9) this finding was supported by shang and yang [17] who found that social support had a positive impact in chinese weightlifters by improving athlete motivation, mental toughness, and reducing burnout. salcinovic et al. [18] also highlighted that supportive team behaviour is one of the key contributing factors to the success of high performance sports teams. social support from teammates, coaches and support staff, family, and friends may present a positive relationship with the athlete's emotional, cognitive, and behavioural aspects, as well as their overall performance outcomes. [18] barriers lack of financial support the majority of athletes reported a lack of financial support, especially at the early stages of their careers in sports. most of the participants highlighted this as an obstacle, as they came from households where money was a scarce resource and their parents could only provide basic needs, while their sporting needs were regarded as luxuries they couldn't afford. at times, athletes who perform well and get selected to compete at national and international competitions were expected to personally fund their way on tours, as most of their families could not afford this, leading to low morale and discouragement. some athletes also highlighted that sports clubs in townships had no sponsorship and were poorly funded, therefore inhibiting them to provide full support to the athletes in need (figure 2). one athlete commented as follows: ‘for us as black people, it's difficult as your still in the development page of the sport as there is very limited financial support that allows you to excel and remain in the sport.’ (athlete 4) this finding was supported by swart, swanepoel, and surujlal [19] who evaluated the south african government expenditure towards the sport and recreation sector and found that the majority of the budget allocation was towards office administration and minimal towards grass roots sports development and school sport. jacobs, de bosscher, and venter [9] also found that the south african government allocated low grants towards elite sport development which could not meet the demands of the sector, with the national olympic body of south africa indicating that it heavily relies on sponsorships to fund its sport programmes. [9] this lack of investment by government eventually compromises the country’s effort in developing talented athletes. financial investment in elite sport creates an enabling environment for athletes to attain international success. [2] one of the other challenging aspects that athletes also reported was having access to sponsorship support at the late stages of their careers. this presents a challenge for the period when the athlete is still at the ‘up-and-coming’ stage of their career. hong and fraser [14] highlight that elite athletes not funded by their national olympic bodies, federations, or sponsors, are most likely to rely on family (mainly parents) and social networks of friends and relatives for financial support in some of the most crucial stages of their sporting journey. athletes from well-resourced households may be able to receive better financial support from their families, whereas those from lower income households may not have the financial means to continue their sporting careers as a consequence of increased financial demands. this may be the reason for the high dropout rates of talented athletes from sports. sports federations in partnership with government and sponsors should establish athlete-centred support programmes that are aimed at identifying talented athletes from marginalised communities, who show potential and provide the necessary financial and non-financial tools to ensure that they are well supported until they achieve financial independence. dysfunctional school sport system most of the athletes reported the dysfunctionality of the school sport system for schools in townships and rural areas as among the greatest obstacles to sports success. it was indicated that most of the township and rural schools do not offer any sport, nor do they have any facilities or equipment, and in some cases, only netball and soccer were the only competitive sporting codes on offer. it was also noted that educators in such schools have no keen interest in sports or encouraging sports participation. a few athletes reported having to migrate to elite schools in town through scholarships to have access to adequate sports infrastructure and support. one commented as follows: ‘it is very concerning that a talented athlete from a township or a village has to be taken from the area to town to attend the elite schools to receive the necessary support.’ (athlete 2) this finding was supported by the finding by kanters et al. [20] who attributed the lack of sports programmes in low-income and predominantly black schools to funding reductions leading to other competing interests (academics demands), poor school sports policies, and exclusive school sports policy which limit sports participation in these schools. noorbhai [10] also indicated that attending an elite (high-income) boys-only school was a strategic contributing factor toward cricket success among south african national cricket players. therefore, it remains a concern that talented athletes from low-income households may need to have access to scholarships to attend elite schools in order to increase their probability of success in most sporting codes. the dysfunctional school sports system, coupled with original research 7 sajsm vol. 35 no.1 2023 poverty and inequality, was also highlighted as one of the main impediments to transformation, access, and equal opportunities within south african sport. the epg transformation report also cited that as few as 2000 former model c public schools have formalised sports programmes. [21] lack of sports facilities and equipment the majority of athletes reported another constraint as a lack of access to professional sporting facilities within their area of residence, especially in the development phase. some athletes reported making use of gravel and grass as their training grounds, or dams with slow water flow for canoeing, for instance. many reported having access to good facilities after achieving elite status. the problem with poor sports facilities is that they affect the longevity of sports equipment, as the equipment is not designed for such terrains (i.e. athletic spikes on a gravel track instead of rubber). this then forces athletes to continuously replace equipment that they cannot afford. some athletes reported having a lack of access to sports equipment throughout the early stages of their career, which led to them loaning from other athletes, and sports clubs, seeking donations of used equipment or sponsorship. one commented as follows: ‘there are no good tracks in the township nor are there gym facilities, so in most cases, we relied on the tar road or gravel road for training.’ ‘we also trained on the gravel track and we did not complain because it made us stronger.’ (athlete 4) some of the athletes reported well-maintained sports training facilities being far from their residential areas, making transportation costs expensive. the athletes also highlighted that most competitions take place in the cities because of a lack of well-maintained and safe sporting facilities in townships and rural areas. this forces them to travel long distances using unreliable and expensive public transport system to be able to train and compete. one commented as follows: ‘for some events, it was more difficult to get to competitions.’ ‘it's still difficult to reach competitions from there until today as most of the events are held in the cities, which are about three hours away from my village.’ (athlete 5) the lack of sports facilities in hdas can largely contribute to the legacy of apartheid whereby predominantly black residential areas were largely underdeveloped in terms of infrastructure, with sports infrastructure forming part of the underdevelopment. [7] the problem of the lack of facilities is not only in communities but also in public schools. the south african national education infrastructure management system report of 2021 found that 10 038 out of 23 276 (43%) south african public schools have no sports facilities. among 80% of these schools are no-fee paying schools in low-income communities mostly in south african rural provinces in limpopo (eastern cape) and kwazulu natal. [22] therefore, shortand long-term interventions need to be implemented by national government to ensure provision and access to sporting infrastructure within hdas. lack of post-career support although most athletes reported receiving bursaries and scholarships, the majority highlighted poor career guidance to prepare for life after sport. most of the athletes indicated that they had to seek opportunities during their sporting career to secure a better future after the sport. some athletes reported losing out on beneficial time to gain valuable workplace experience as they were full-time athletes. one athlete commented as follows: ‘to be honest, there aren't enough opportunities that propel you like a clear pathway, you create your new path to force your way through, but most of the time it's not easy.’ (athlete 12) dos santos et al [23] showed a similar finding whereby 379 brazilian elite athletes reported having anxiety and apprehension over the uncertainty of their future after sport as a consequence of insufficient post-career support. they indicated that this also affected their performance on the field of play. hong and fraser [24] reported an increased risk of mental health problems among athlete retirees who are poorly supported, especially those facing financial distress. therefore, it is recommended that sport becomes more professionalised and that elite athletes who represent the country internationally should be presented with similar benefits as those of full-time employees, ensuring that they have access to pension fund schemes, medical insurance, and unemployment insurance funds (uif). this will ensure that athletes have post-retirement benefits to kick-start their life after sport while seeking new opportunities. this intervention can be implemented by the government, working together with national federations. mazzei et al. [2] who also reported insufficient post-sport career support in brazil, suggested that a new model of athlete support needs to be established, especially in the education sector, to enable athletes to build their professional careers. therefore, it is also advisable for athletes, in the south african context, to become student-athletes and enrol in universities or colleges through sports bursaries, to acquire qualifications and skills they can use post-retirement. poor scientific support the majority of athletes reported having poor scientific support throughout their sporting careers. scientific support relates to access to the latest research in training and performance, individualised training regimes, and access to sports scientists, sports medicine specialists, and other professional support structures. some highlighted only having access to such support at a later age when they had reached elite status. few athletes indicated that should they have had access to good scientific support throughout their career, they would have perhaps won an olympic medal. ‘we had no access to high-performance centres or any scientific support in the townships. in most cases there is no support in such instances unless you make the team go compete at olympics, then in weeks before the games, you will have access to some sort of scientific testing or high-performance testing sessions.’ (athlete 4) mthombeni, coopoo, and noorbhai [25] reported similar findings when evaluating the availability of support systems by original research sajsm vol. 35 no.1 2023 8 south african national sport federations, whereby majority reported a lack of scientific support programmes within their administration. sports science research and scientific support leads to evidence-based training regimes that allow athletes to perform optimally. this is more important for an individual-specific scientific-backed programme and training. poor scientific support to athletes often leads to them falling victim to pseudoscientific practices, including the use of unproven training techniques, the wastage of money on supplements that do not improve their athletic ability, and other misleading practices that sports people fall victim to. with evolving technology, sport has become more competitive and scientific. sports scientists and medical professionals can now leverage application software, social media, and other forms of technological interventions to assist athletes in achieving optimal performance. this makes scientific support more important now, than ever before. one of the studies by kubayi, coopoo, and toriola [26] found that coaches have previously reported that the most important priorities in providing scientific support to athletes were technique improvement, injury prevention, peaking for competition, as well as mental strength. therefore, it is important to bridge a gap between sports science support and coaching to ensure that coaches have access to evidence-based regimes to impart to athletes. limitations the limitation of the study was that it was only qualitative and had to rely on subjective data from a selected cohort of athletes. however, the qualitative method was also a strength of the study in that it provided rich in-depth and lived experiences of athletes. another limitation was that the participants were all black african athletes, limiting the diversity of views from different racial groups. future studies should focus on a quantitative model of measuring elite athlete support systems. the study only focused on collecting data from former olympians and did not focus on the current developmental athletes which would indulge in the challenges they are facing currently. conclusion the study showed that south african athletes from hdas attributed their sporting success to the functional club system sport structure, access to sports at the community level, access to scholarships and bursaries to elite schools or universities, good coaching support and mentorship, access to local and international competitions, as well as community and peer athlete support. the highest barriers reported by athletes were inadequate financial support (especially during the developmental stages of their career), a dysfunctional school sports system, lack of sports facilities, equipment and transport system, poor post-career support, as well as lack of scientific support. financial investment in elite sports is necessary for the country to achieve its full potential for international success. developing (up-and-coming) athletes from hdas need to be financially supported consistently through athlete-centred support programmes to ensure that they have access to the necessary resources for them to excel in their respective sporting codes. the government should ensure that organised sport becomes a compulsory component of the schooling system across all south african schools. the national government should take on the responsibility for the provision of adequate sports facilities in hdas. elite athletes who have represented south africa internationally should be protected under the nation's labour laws to ensure that they have similar benefits to ordinary employees for them to enjoy social protection. there needs to be a bridging of the knowledge gap between coaches and sports scientists to allow coaches to use evidence-based approaches in athletic training and programming. future studies need to focus on in-depth analysis of evaluating the impact of class, socioeconomic status, gender and the impact of such variables in providing access, participation, and success in sports. future studies should also provide a sport-specific analysis to assess which sports are more accessible than others by athletes from hdas and factors that may be enablers or hindrances to participation in specific sporting codes. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: 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http://dx.doi.org/10.1186/s40798-021-00406-7 https://hdl.handle.net/10520/ejc162509 http://dx.doi.org/10.1007/s12160-012-9413-2 https://www.srsa.gov.za/sites/default/files/epg%20summary%20transformation%20audit%20report%202018_2019_lr.pdf https://www.srsa.gov.za/sites/default/files/epg%20summary%20transformation%20audit%20report%202018_2019_lr.pdf http://dx.doi.org/10.3390/jrfm14070324 http://dx.doi.org/10.30819/iss.44-2.03 original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license prevalence of the relative age effect among high-performance, university student-athletes, versus an age-matched student cohort s dube, msc; h grobbelaar, phd division of sport science, department of exercise, sport and lifestyle medicine, faculty of medicine and health sciences, stellenbosch university, stellenbosch, south africa corresponding author: h grobbelaar (hgrobbelaar@sun.ac.za) the relative age effect (rae) refers to the overrepresentation of athletes born earlier in the calendar year covering a specific sport. rae is determined by birth date concerning age-group cut-off dates.[1] these differences are typically associated with shortand/or long-term effects universally known as the relative age effects (raes).[2] the rae is expressed by the difference between expected and the observed birthdate distributions of participants.[3] research is consistent in reporting the immediate and long-term selection, attainment and participation advantages enjoyed by relatively older participants (i.e. those born earlier in the selection year).[3] these outcomes extend across developmental periods but appear to be deep-rooted and most pronounced in competitive adolescent male team sports.[1] importantly, raes are not reinforced by a single factor. supported by a range of descriptive data over the last three decades, a combination of physical, psychological, motivational and socialization factors work together to produce the effect.[1,4] once participants are selected, they will have access to better coaches, training facilities, and competitive opportunities.[5] this becomes a key aspect of their future sporting career, resulting in the continued prevalence of the rae at senior sporting levels.[5,6] while age-related factors are critical antecedents of raes, they are also reinforced by more global factors (i.e. depth of competition and the skill level required), which influence the developmental context.[4] recent evidence points to a rae reversal at senior elite levels, suggesting that relatively younger athletes may be more likely to experience success and enjoy longer careers compared to relatively older players.[7,8] one possible explanation for this reversal is that at the senior sports level and in certain individual sports, technical, tactical and psychological traits become more valued than body size.[7] once the physical advantage that relatively older individuals typically enjoy during adolescent sports is no longer prevalent, superior skills gained by relatively younger players, who persist in an unfavourable system, place them at an advantage.[7–9] being relatively younger is therefore not an automatic disadvantage for all youth sports participants. however, it is a disadvantage for most relatively younger athletes. any reversal affects a small proportion of q4-born athletes, whereas the overall rae affects a much higher proportion of youth sports participants. whilst most rae studies have focused on youth and professional sport,[2] few studies have investigated this prevalence among university student-athletes. south africa’s sports system is uniquely organised into competitive school and university sport which often forms part of the pathway to elite sport, compared to elsewhere in the world where club sport tends to dominate.[10] stellenbosch university has a high performance sports unit that selects a limited number of student-athletes into its talent development programme each year. this stream offers differentiated experiences, including better coaches, sport science services and opportunities for televised competitions (e.g. varsity sport/varsity cup). selection into the hp programme is prestigious and represents a facet of cultural identity, which probably proliferates competition and selection pressure.[4] these factors make it a suitable environment for the rae to be prevalent, as many participants compete for the limited number of positions and resources.[4] this study aimed to determine if the rae is prevalent among hp-student-athletes across academic years, sport codes and sex, compared to an age-matched student cohort. this is a pertinent inquiry as it highlights the magnitude of the rae and adds to the few studies on south african student-athletes.[11] the study attempts to fill this gap in the literature by focusing background: relative age effect (rae) refers to the overrepresentation of athletes born earlier in the calendar year covering a specific sport. the rae is especially prevalent in youth sports but often persists into senior competitive levels. objectives: to determine the prevalence and magnitude of the rae among student-athletes in a high performance (hp) programme at a south african university, according to year, sports code and sex, compared to the general student cohort. methods: cross-sectional descriptive analysis of hp-studentathletes and an age-matched student cohort from 2016 to 2021. birthdate data were extracted for the hp student-athletes (n = 950: men = 644, women = 306) and student comparison group (n = 47 068; men = 20 464; women = 26 591; not disclosed = 13). differences were determined using chi-squared and fisher’s exact test. residuals examined relative age quartile differences. the steps were applied across academic years, sport code and sex results: the rae was more pronounced among the studentathletes compared to the age-matched student cohort. the rae was occasionally observed among the hp-studentathletes; however, the prevalence was inconsistent across the respective years under investigation and only noted in certain sport codes (i.e. swimming, rugby union and cricket). there were no sex differences among the hp student-athletes. conclusion: where the rae was noted, the selection bias favoured the relatively older student-athletes. the mechanisms for rae are multifactorial and complex. a combination of factors, such as competition depth, the popularity and physicality of a sport and socialisation may be involved. keywords: university sport, birth quartiles, selection bias, birth dates s afr j sports med 2022;34:1-6. doi: 10.17159/2078-516x/2022/v34i1a13310 mailto:hgrobbelaar@sun.ac.za http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13310 https://orcid.org/0000-0003-0616-5933 https://orcid.org/0000-0001-9056-4691 original research sajsm vol. 34 no.1 2022 2 on the timeline and impact the rae makes when prevalent in youth sports, and may provide insight into the selection and participation patterns of university student-athletes. the researchers hypothesised that the rae will be prevalent and that there would be a bias towards relatively older studentathletes being selected for high-performance opportunities. methods ethical approval was received from the su research ethics committee for social, behavioural and educational research (rec: sbe project number: 21919), and institutional permission was granted by the division for information governance (ig-2166). since the data did not contain identifiable information, informed consent was not required. the study was conducted according to the declaration of helsinki. we included date of birth data of south african su students aged 18 to 25 years from 2016 to 2021. the study was delimited to the last six years for which complete data sets exist for the student-athletes. this is when maties sport started the induction, monitoring, and tracking of their hpstudent-athletes. since the hp programmes focus on varsity sport/varsity cup sporting codes, 25 years was set as the maximum age for the student-athletes, coinciding with the competition age limit. non-south-africans were excluded to ensure that all participants were subject to the same cutoff date (1 january) used for age-group categorisation. all 128 230 data records were analysed in rstudio. to ensure that the participants in each academic year were unique and included once only, the analysis was restricted to the new intake students for each year (n = 48 018). the data was divided into two groups: (1) general student cohort (n = 47 068; men = 20 464; women = 26 591; not disclosed = 13), and (2) hp-student-athletes (n = 950; men = 644; women = 306). the student-athletes consisted of 11 hp sport codes: athletics = 90; basketball = 67; cricket = 77; cycling = 33; field hockey = 133; netball = 67; rugby union = 260; soccer = 95; swimming = 72; tennis = 40; water polo = 16). it was essential to impose a comparison cluster of aged-matched general students to assess whether the rae was prevalent in the general student population or whether the phenomenon is sport-specific. starting with january, all participants were grouped into quartiles (q1: january to march, q2: april to june, q3: july to september, q4: october to december). the chi-square goodness of fit test was used to test differences in birth quartile frequencies of the full student population against a theoretical expected distribution, a day-corrected quartile distribution (q1 = 24.7%, q2 = 24.9%, q3 = 25.2%, q4 = 25.2%).[3] compared to a uniform distribution (25% per quartile), the day-corrected distribution accounts for the varying number of days per month.[3] a series of chi-squared tests of independence (χ2) was used to test differences in birth quartile frequencies of the hp-student-athletes against the general student cohort according to year and sex. fisher’s exact tests were used to assess significant differences in birth quartile frequencies according to sport code. for all analyses, a p-value of <0.05 was the criterion for a significant difference in distributions. furthermore, cramer’s v identified the magnitude of the effect size. a post hoc test to calculate the standardised residuals (sr) was used to determine which birth quartiles differed significantly from the expected distribution. since all the quartile distribution comparisons had df = 3, cramer’s v was interpreted as follows: <0.06 = trivial effect; 0.06 < v ≤ 0.16 = small effect; 0.17 ≤ v < 0.29 = medium effect; and v > 0.29 = large effect and residuals > 1.96 = overrepresentation, while < -1.96 = under-representation of births. results for the general student population (south african students, age-matched to the student-athlete’s q1 = 27%, q2 = 25%, q3 = 25%, q4 = 23%, a rae was evident (χ2 = 272.42, p < 0.01, cramer’s v = 0.02) when compared to the day count distribution. a follow up χ2 test of independence confirmed a significant association between sex and birth quarter among the student population (χ2 = 21.28, p < 0.01, cramer’s v = 0.02) with a quartile distribution [residual] for men (q1 = 28% [2.40], q2 = 26% [0.75], q3 = 24% [-1.64], q4 = 22% [-1.70]) and women (q1 = 27% [-2.13], q2 = 25% [-0.66], q3= 25% [1.46], q4 = 23% [1.51]). table 1 contains the between-group comparison results per sex (i.e., hp-student-athlete men/women versus generalstudent-cohort men/women) and year. table 2 reports the fisher’s exact test results and residuals for each sport code. figure 1 depicts the group differences in birthdate distribution for the hp-student-athletes and the general student cohort for each year. figure 2 graphically illustrates the birth quartile between-sex differences among the hp-student-athletes. figure 3 revealed the between-sex comparisons for the generalstudent-cohort as well as the eight sport codes that comprised men and women participants. birth quartile graphs for netball (women players only) and for rugby and cricket (men only) complete the figure. the birthdate distribution of the hp-student-athletes differed from the student cohort. there were no raes in 2016 and 2018, despite consistent q1 and q2 over-representation. raes were more prevalent among the men compared to the women student-athletes. between-sex differences (medium effect) were noticeable in 2016 only. a ‘spike’ was noted during q2 in 2017, before normalising again in 2018. from 2019 onwards, the relative distribution in q1 and q2 hp-student-athletes increased for both sexes. among the women student-athletes, a substantial increase was evident in those born during q2 over the six years. there were no between-sex differences when men and women student-athletes from the same sport code were compared. discussion to the best of our knowledge, this is the first study to investigate the prevalence and magnitude of the rae among south african university student-athletes. the rae was more pronounced among the student-athlete sample compared to the age-matched student cohort. interestingly, the birth distribution of the student population was slightly skewed towards relatively older students. the prevalence of the rae among the student population, albeit small, would extend to original research 3 sajsm vol. 34 no.1 2022 maxi table 1. results from the chi-square test (χ2) of independence for between-group differences for each sex and academic year academic year general-student-cohort n (% in group) hp-student-athletes n (% in group) χ2 (df = 3) p-value cramer’s v men 2016 8 915 (44) 163 (69) 5.59 0.13 0.02 men 2017 2 413 (44) 156 (80) 9.87 0.05* 0.05 men 2018 2 262 (43) 85 (67) 3.96 0.27 0.02 men 2019 2 202 (43) 50 (49) 9.64 0.02* 0.05 men 2020 2 336 (43) 108 (68) 6.18 0.10 0.04 men 2021 2 336 (43) 82 (64) 10.17 0.02* 0.05 women 2016 11 315 (56) 74 (31) 11.42 < 0.01* 0.03 women 2017 3 107 (56) 40 (20) 0.01 0.99 0.00 women 2018 3 045 (57) 42 (33) 2.49 0.48 0.00 women 2019 2 929 (57) 53 (51) 3.85 0.28 0.02 women 2020 3 080 (57) 50 (32) 8.37 0.04* 0.04 women 2021 3 115 (57) 47 (36) 4.39 0.22 0.02 * indicates significant differences (p < 0.05). % represent the percentage of total men and women participants per group in an academic year. table 2. results from the fisher’s exact test and residuals for each sport code sport code men (n) women (n) total (n) p-value q1 residual q2 residual q3 residual q4 residual athletics 43 47 90 0.58 -1.13 -0.37 -0.70 0.12 basketball 34 33 67 0.77 0.20 0.01 0.59 -0.84 football 78 17 95 0.36 1.43 -0.21 -0.31 -1.00 hockey 65 68 133 0.18 1.16 0.92 -0.86 -1.33 swimming 34 38 72 <0.01* 0.33 1.82 0.28 -2.57# tennis 20 20 40 0.79 0.35 0.59 -0.61 -0.37 cycling 23 10 33 0.12 -0.65 -0.12 2.04# -1.29 water polo 11 5 16 0.81 0.80 -0.52 0.02 -0.34 netball 0 67 67 0.54 0.66 0.74 -0.64 -0.84 rugby 259 1 260 <0.01* 2.00# 1.66 -1.27 -2.61# cricket 77 0 77 <0.01* 2.87# 1.47 -2.08# -2.52# * indicates significant differences (p < 0.05); # indicates significant residuals (± 1.96). fig. 1. results from the chi-square test of independence between-groups according to the academic year. n indicates total number of students. p, χ2 and v values indicates birth quarter difference for the year. dotted line at 25% indicates reference for uniform distribution. original research sajsm vol. 34 no.1 2022 4 the hp-student-athlete sample, increasing the likelihood that more q1 and q2-born athletes would be competing at this level. the rae was only occasionally observed among the hp student-athletes, but the prevalence was inconsistent across the respective years and sports codes. it was more commonly not prevalent than prevalent when the respective subgroups were compared. the hp student-athletes’ birthdate distribution differed significantly from that of the general student cohort, respectively for two (women sample) and three (men sample) of the six years under investigation. the rae was only prevalent in three of the sport codes: swimming, cricket, and rugby, and there were no sex differences among the hp student-athletes. the actions of different social agents and contextual factors (e.g. developmental pathway, the level of competitiveness and sports popularity) may have contributed to these sport-specific findings.[4,12] the initial selection bias may have merely perpetuated over time.[5] by doing better, relatively older athletes probably received more rewards for their accomplishments, leading to greater psychosocial fig. 2. results from the chi-square test of independence between-sex for hp-student-athletes. n indicates total number of hp-studentathletes. p, χ2 and v values indicates birth quarter difference for the year. dotted line at 25% indicates reference for uniform distribution. fig. 3. distribution of birth quarter for each sport code by sex. dotted line at 25% indicates reference for uniform distribution. original research 5 sajsm vol. 34 no.1 2022 investment and a better prospect of retaining their participation status, resulting in the raes still being prevalent at university sports levels.[4,6] the findings for swimming (i.e. more q2 than q1-born swimmers) are atypical and may be attributed to a higher likelihood of an unusual distribution by mere chance, due to the small sample size. still, there was a bias towards swimmers born in the first half of the year. structural changes to the south african first-class cricket competition (i.e. cutting the 11 professional teams to six franchises, thereby reducing the viable development pathways) may have contributed to the rae observed among the cricket players.[13] once relatively younger participants deviate from the traditional player pathway, they might find themselves in a development and learning environment against weaker competition and restricted opportunities for progression.[13,14] the rae observed in this study resonates with previous high school[15] and senior[6] rugby union research in south africa, thereby adding more information about the pathway to professional rugby. rugby union is a strong candidate for rae prevalence based on high physicality (task constraint), cultural relevance and popularity (environmental constraints).[2,6] a residual bias may accumulate from being selected early in the process. subsequently, fewer relatively younger players may come through the tertiary education pathway.[13] it is difficult to explain the absence of the rae in soccer and basketball, considering the consistent prevalence reported in these sports in other contexts.[12,16] if students only take up sport later in life, i.e. post-puberty, there could be fewer development variations (e.g. weight, height) when they reach the university sports level. this may reduce physical selection biases and the prevalence of the rae. additionally, in comparison to rugby union and cricket, few soccer and basketball players use university sports as a springboard to elite sports. sports like basketball and soccer may adopt a more flexible approach, where university coaches tend to accept almost any student who wants to be part of the programme, which encourages more students to join these programmes regardless of their initial skill and/or experience, thereby possibly moderating the rae. the data showed that only 2% of the student population was part of the hp-student-athlete programme. women were under-represented in the hp-student-athlete cohort (32% women vs 68% men). this is concerning, considering there were more women than men students (approximately 57% vs 43%, respectively), and raises questions about the underrepresentation of women in university sports. the differential distributions observed in women hp-student-athletes could be explained by socialisation or a self-restriction process. the “gender inappropriate” stigma attached to the female sport may have weakened results, allowing the relatively older woman and relatively younger student-athletes to continue their participation. psychological perspectives embrace the notion of the selffulfilling prophecy, i.e. the greater the expectation (selfexpectations, coach or parent expectations) placed on the player, the greater the achievement result.[5] studies revealed that coaches held greater expectations of participants born in the first quarter (q1) of the year than those born in the fourth quarter (q4).[17] the support provided to athletes during key developmental periods and the developmental experiences created during practice sessions and matches influence their transition and progression.[1,18] hence, to limit the possible negative consequences of the rae, swimming, rugby, and cricket administrators should offer diverse solutions to benefit all participants during different participation and development phases. talent selection programmes should incorporate a broad range of selection criteria including objective assessments of physical attributes, technical skills, and psychosocial characteristics. considering that relatively younger players can still reach top-level senior sports, practitioners should consider the delayed development trajectories of some of the young participants and support participants as they transition from high school to university teams. this support is needed both before and once they arrive at university. although several solutions have been proposed for youth sports,[19] few have been implemented successfully or tested empirically. whilst raising awareness is important to address the rae, it is likely to be insufficient. moreover, it would be naive to enforce any of the earlier practical recommendations as solutions to reduce this phenomenon because of the absence of direct evidence that their application will reduce the effect. furthermore, the current findings were limited to information on date of birth, sports codes and sex. it may be too late to impel such interventions at the university sport participation level. focusing on developing a broader understanding of the processes influencing early and late developing studentathletes may be more appropriate. conclusion a small rae was observed among the general student cohort. analyses of the subgroups revealed inconsistent annual variations among the hp-student-athletes. the rae was further confined to swimming, cricket, and rugby only, and there were no sex differences in the hp-student-athlete cohort. the observed rae exemplifies a social inequality that inhibits the prospect of immediate and long-term participation in university hp sport. even though south african studentathletes are seldom professionals, equal opportunities should be given to everyone to become an hp student-athlete, regardless of date of birth. even if this bias is unintended, it should be prudently assessed, given the rewarding nature of some sport codes (e.g. access to high-quality resources, television coverage, recognition, financial and academic support). the prevalence of the rae in these sports may point toward underlying mechanisms and problems with the talent identification, selection, and youth sport development initiatives. a limitation to this study is the small sample size (especially when split into sport codes). whilst the present study is representative of student-athletes from a south african university and provides information on the general prevalence original research sajsm vol. 34 no.1 2022 6 of the rae at this competitive level, it is not comprehensive. findings from this study are therefore context-specific and should not be generalised to studies from other universities or countries. future studies should examine the mechanisms responsible for the prevalence of rae or the lack thereof at various participation levels (e.g. primary school, high school, and sports academies). though not examined in this study, it is reasonable to assume a degree of interaction among various constraints. various individual physical abilities and psychological skills, tasks (playing position, participation level and physicality of the sport), and environmental constraints (popularity of the sport, coach and family influence, sport-code rules, and policies) should be considered and measured explicitly to gain a better understanding of their association with the rae. our understanding of these interactions remains limited. studies may also benefit from triangulating findings from qualitative and quantitative sources and should utilise a sound theoretical framework, such as the athletic talent development environment model.[20] conflict of interest and source of funding: the authors declare no conflict of interest. sd received funding from the stellenbosch university postgraduate scholarship programme. acknowledgements: we thank the stellenbosch university division for information governance and maties sport for their cooperation and access to the data and prof. martin kidd from the centre for statistical consultation services for assisting with the statistical analysis and interpretation. author contributions: sd and hg conceptualised the study, sd received ethical clearance, engaged with the respective divisions for access to the datasets, conducted the statistical analysis, in consultation with a statistician, and drafted the manuscript. hg supervised and provided critical feedback throughout. references 1. wattie n, schorer j, baker j. the relative age effect in sport: a developmental systems model. sport med 2015; 45(1):83–94. [doi: 10.1007/s40279-014-0248-9] [pmid: 25169442] 2. cobley s, baker j, wattie n, et al. annual age-grouping and athlete development: a meta-analytical review of relative age effects in sport. sport med 2009; 39(3):235–256. [doi: 10.2165/00007256-200939030-00005] 3. delorme n, champely s. relative age effect and chi-squared statistics. int rev sociol sport 2015; 50(6):740–746. [doi: 10.1177/1012690213493104] 4. schorer j, cobley s, bräutigam h, et al. developmental contexts, depth of competition and relative age effects in sport: a database analysis and a quasiexperiment. psychol test assess model 2015; 57(1):126–143. 5. hancock dj, adler al, côté j. a proposed theoretical model to explain relative age effects in sport. eur j sport sci 2013; 13(6):630–637. [doi: 10.1080/17461391.2013.775352] 6. kearney pe. the influence of nationality and playing position on relative age effects in rugby union: a cross-cultural comparison. s afr j sports med 2017; 29(1):1–4. [doi: 10.17159/2078516x/2017/v29i1a4238] 7. jones bd, lawrence gp, hardy l. new evidence of relative age effects in “super-elite” sportsmen: a case for the survival and evolution of the fittest. j sports sci 2018; 36(6):697–703. [doi: 10.1080/02640414.2017.1332420] [pmid: 28627293] 8. kelly al, till k, jackson dt, et al. talent identification and relative age effects in english male rugby union pathways: from entry to expertise. front sports act living 2021; 3:640607. [doi: 10.3389/fspor.2021.640607] [pmid: 33681762] 9. mccarthy n, collins d, court d. start hard, finish better: further evidence for the reversal of the rae advantage. j sports sci 2016; 34(15):1461–1465. [doi: 10.1080/02640414.2015.1119297] [pmid: 26651240] 10. jacobs s, de bosscher v, venter r, et al. country profile: sport in south africa. int j sport policy polit 2019; 11(1):175–191. [doi: 10.1080/19406940.2018.1547780] 11. nthangeni s, toriola a, paul y, et al. student-athlete or athletestudent: analysis of benefits and barriers of university sport participation in south africa 2021; ann appl sport science 9(2): e924. 12. steingröver c, wattie n, baker j, et al. does relative age affect career length in north american professional sports? sport med open 2016; 2(18):1–7. [doi: 10.1186/s40798-016-0042-3] [pmid: 26807348] 13. english c, nash c, martindale r. the effects of structural change: an investigation into the south african cricket development pathway. int j sport policy politics 2018; 10(2):371–391. [doi: 10.1080/19406940.2018.1434811] 14. mollerloken ne, loras h, pedersen av. a systematic review and meta-analysis of dropout rates in youth soccer. percept mot skills 2015:121; 913–922. [doi: 10.2466/10.pms.121c23x0] [pmid: 26595205] 15. grobler td, shaw bs, coopoo y. relative age effect (rae) in male school-aged rugby union players from gauteng, south africa. african j phys act heal sci 2016; 22(2):626–634 16. lupo c, boccia g, ungureanu an, et al. the beginning of senior career in team sport is affected by relative age effect. front psychol 2019; 10: 1465. [doi: 10.3389/fpsyg.2019.01465] [pmid: 31293489] 17. peña-gonzález i, fernández-fernández j, moya-ramón m, et al. relative age effect, biological maturation, and coaches’ efficacy expectations in young male soccer players. res q exerc sport 2018; 89(3):373–379. [doi: 10.1080/02701367.2018.1486003] [pmid: 30015598] 18. tribolet r, watsford ml, coutts aj, et al. from entry to elite: the relative age effect in the australian football talent pathway. j sci med sport 2019; 22(6):741–745. [doi: 10.1016/j.jsams.2018.12.014] [pmid: 30598253] 19. webdale k, baker j, schorer j, et al. solving sport’s ‘relative age’ problem: a systematic review of proposed solutions. int rev sport exerc psychol 2020; 13(1):187–204. [doi: 10.1080/1750984x.2019.1675083] 20. henriksen k, stambulova n, roessler kk. holistic approach to athletic talent development environments: a successful sailing milieu. psychol sport exerc 2010; 11(3):212–222. [doi: 10.1016/j.psychsport.2009.10.005] sportsmed_june04 sports medicine vol 16 no.2 2004 33 introduction protein turnover (protein synthesis and breakdown) is typically increased during and post-exercise. with heavy resistance exercise certain muscle fibres are disrupted or damaged and need to undergo a remodelling and repair process during the recovery period.16 for a detailed review of exercise-induced muscle damage and inflammation see pyne.56 muscle damage or disruption (protein breakdown) is influenced by the duration, intensity and type of exercise (eccentric vs. concentric), as well as training status.16 it has been shown that with regular exercise training, the rise in protein breakdown is attenuated.54 during endurance-type training there is also an increase in protein breakdown in order to sustain exercise metabolism, which increases when muscle glycogen stores are depleted. in order for muscle repair, recovery and adaptation to take place post-exercise, a positive nitrogen balance is needed in order to allow for a state of net protein synthesis.71 this shift from a catabolic to anabolic state is mediated by the presence of certain dietary nutrients, hormones and growth factors.71 protein synthesis and skeletal muscle repair post-exercise have been shown to increase in response to adequate energy and amino acid availability, while protein breakdown is decreased by insulin.68 furthermore, resistance exercise and amino acid availability have additive effects in terms of protein synthesis.6 this article (part ii) will focus on dietary factors that contribute to protein synthesis and skeletal muscle repair during the recovery period. review article dietary macronutrient recommendations for optimal recovery post-exercise: part ii h h wright (msc dietetics, phd nutrition)1 a claassen (bsc (hons) dietetics, bsc (med) (hons) exercise science)2 j davidson (dsc)3 1potchefstroom institute of nutrition, faculty of health sciences, northwest university, south africa 2uct/mrc research unit for exercise science and sports medicine, faculty of health sciences, university of cape town, south africa 3college of education and health sciences, bradley university, peoria, illinois, usa correspondence: h wright school of physiology, nutrition and consumer science north-west university private bag x6001 potchefstroom, 2531 tel: 018-299 2482 fax: 018-299 2464 e-mail: vgehhw@puk.ac.za abstract a net positive nitrogen balance is needed for exerciseinduced muscle damage to be repaired during the recovery period. apart from hormones and growth factors, adequate energy and amino acid availability contribute to this balance and influence the rate at which protein synthesis and muscle repair occur post-exercise. this paper reviews the dietary factors involved in muscle repair during the post-exercise recovery period. both resistance and endurance-trained athletes have a higher dietary protein requirement of between 1.2 and 1.8 g protein/kg body weight (bw)/day, with an upper limit of 2 g protein/kg bw/day. to increase the rate of protein synthesis during the recovery period, immediate ingestion of protein postexercise is recommended. additionally, ingesting 1.2 g carbohydrate (cho)/kg bw/hour with 0.4 g/kg bw/hour of a wheat amino acid mixture (wheat protein hydrolysate combined with free leucine and phenylalanine) enhances the insulin response compared with ingesting cho only or combined with other protein hydrolysates, peptides, or intact protein. this increased insulin response could increase muscle protein synthesis indirectly by altering the hormonal milieu. results on the anabolic effect of single or mixtures of amino acids remains to be further elucidated. the possible antioxidant benefits of whey protein supplementation in athletes remains to be proven, while the antioxidant potential of soy protein holds promise. the effect of glutamine supplementation on protein synthesis in athletes is limited and its clinical relevance for enhanced immune function in endurance athletes remains to be established. creatine supplementation seems to be beneficial in terms of protein synthesis and gains in fat free mass during the recovery period, while the use β-hydroxy β-methylbutyrate (hmb) supplementation by trained athletes seems to have limited benefits. it is important to keep dietary advice individualised considering the complexity in which the endocrine system regulates cell function, the diverse mechanisms that control homeostasis, as well as genetic variability. 34 sports medicine vol 16 no.2 2004 dietary factors involved in muscle repair overall dietary protein requirements with regular exercise training intensive and/or high-volume aerobic and weight-training exercise increase the protein requirement for muscle repair, adaptation, and to remain in positive nitrogen balance.1 during prolonged endurance exercise, protein may also contribute as fuel to the overall energy demand, however, this contribution remains small (< 5 10%), with carbohydrate (cho) and fat contributing to most of the energy demand.60 at the onset of a training programme, protein requirements may be slightly higher compared with the latter part of a training cycle where adaptation has already taken place.40 a range of 1.2 1.8 g protein/kg body weight (bw)/day is recommended for resistance and/or endurance-trained athletes, however, an upper limit for protein ingestion has been set at 2 g/kg bw/day beyond which there is no added benefit of ingesting more protein. ingesting > 2 g protein/kg bw/day will not enhance muscle repair and adaptation any further,1 and may be detrimental to health.23 one exception would be athletes training at high altitude, which elicits a greater catabolic response and increases protein requirements to ~ 2.2 g protein/kg bw/day in order to remain in positive nitrogen balance.66 timing of protein intake an amino acid tracer infusion study (~ 0.15 g amino acid mixture/kg bw/hour for 3 hours) by biolo and co-workers6 indicated an increased rate of muscle protein synthesis with hyperaminoacidaemia post-exercise compared with rest. this was supported by rasmussen and co-workers58 who found that ingesting an essential amino acid-cho supplement (6 g amino acids + 35 g sucrose/serving) at 1 or 3 hours after resistance exercise resulted in similar rates of muscle protein synthesis, which was ~ 400% above pre-drink values. levenhagen and co-workers42 then showed that ingesting a high-protein supplement (10 g protein + 8 g cho + 3 g fat/serving) immediately after an exercise bout (cycling for 60 minutes at 60% maximal oxygen uptake (vo2max)) enhanced whole-body protein synthesis three-fold compared with delayed ingestion (3 hours post-exercise), and significantly increased dynamic and isokinetic strength.19 levenhagen and co-workers41 also investigated the potential of nutrient intake post-exercise in terms of enhanced recovery of whole-body and skeletal muscle protein homeostasis. subjects were given either a placebo, a cho-fat supplement (8 g cho + 3 g fat/serving), or a cho-proteinfat supplement (8 g cho + 10 g protein + 3 g fat/serving) immediately after a 60-minute exercise period (cycling at 60% vo2max). after a 2-hour recovery period there was a net gain in whole-body protein and leg protein in the cho-protein-fat supplement group, while the placebo and cho-fat supplement group resulted in a net loss in the same measurements. from these results it can be concluded that amino acid availability post-exercise is more important than energy for muscle repair and synthesis during recovery. a study by tipton and co-workers70 found an increased rate of muscle protein synthesis 1 hour after resistance exercise when an oral essential amino acid-cho supplement (35 g sucrose + 6 g essential amino acids) were given prior to the exercise bout compared with immediately afterwards. the main contributor to this increase was an increased delivery of amino acids to the muscle when ingested prior to exercise. in summary, it seems that the earlier amino acids are available post-exercise, the quicker a positive nitrogen balance can be achieved which could contribute to increased muscle protein synthesis, hypertrophy and strength. ingestion of protein or amino acids prior to exercise might have beneficial effects on enhancing post-exercise recovery, however, further research is needed to confirm this effect. furthemore, pre-exercise protein ingestion may have ergolytic effects due to increased ammonia production (explained in more detail later).13,43 type of protein and amino acids since amino acids and their metabolites are involved in muscle repair,6 post-exercise ingestion of intact protein, or supplementation with specific amino acids and their metabolites has been suggested to optimise muscle repair and adaptation. adequate essential amino acids may be derived from the ingestion of intact protein, either in animal or soy-based foods.78 available protein products include whey protein, milk isolates, caseinates, soy isolates, and other vegetable proteins. there is no consensus regarding which protein type is the best. it is important to note that ingestion of amino acids, when dietary protein intake is sufficient, does not further increase the rate of muscle repair.66 furthermore, unrestricted supplementation with single amino acids or amino acid mixtures is associated with metabolic imbalances, toxicity, as well as degeneration of myofibrils and disrupted mitochondrial membranes.23;37 protein peptides/hydrolysates van loon and co-workers73 investigated the insulinotrophic effect of various drinks containing 0.8 g cho/kg bw/hour combined with 0.4 g/kg bw/hour of different combinations of amino acids and/or protein sources ingested under resting conditions. the drinks were given at 30-minute intervals over a 2-hour period. their main finding was that the oral intake of 0.4g/kg bw/hour of wheat protein hydrolysate combined with free leucine and free phenylalanine in the postabsorptive, resting state can produce a larger (~100%) insulin response when compared with the ingestion of cho only, and comparable with the ingestion of a drink containing 0.4 g/kg bw/hour of free leucine, free phelylalanine and arginine. this drink, however, did not produce the severe symptoms of gastro-intestinal upset and diarrhoea that was observed with the ingestion of drinks containing large doses of free amino acids, particularly free leucine, arginine, phenylalanine and glutamine.73 when comparing the ingestion of protein hydrolysates with intact protein, it was concluded that the use of protein hydrolysates is more preferable seeing that it results in a faster increase in plasma amino acid concentrations and stimulation of insulin secretion during a 2-hour period compared with intact protein.73 sports medicine vol 16 no.2 2004 35 subsequently, van loon et al.72 investigated the insulinotrophic effects of post-exercise ingestion of 1.2 g cho/kg bw/hour combined with differing amounts of wheat protein hydrolysate (0.2 or 0.4 g/kg bw/hour), with or without free leucine and phenylalanie at 30-minute intervals up to 3 hours post-exercise in trained men. ingestion of wheat hydrolysate only (either 0.2 or 0.4 g/kg bw/hour) combined with 1.2 g cho/kg bw/hour did not increase post-exercise insulin response compared with the ingestion of 1.2 g/kg bw/hour of cho only. however, addition of free leucine and phenylalanine resulted in a substantial increase in insulin response. additionally, a dose-related effect existed seeing that increasing the amount of wheat-amino acid mixture from 0.2 to 0.4 g/kg bw/hour resulted in a significant increase in the insulin response. furthermore, a strong positive correlation between insulin response and plasma leucine, pheylanaline and tyrosine concentrations existed.73 increased plasma amino acid concentrations may directly (by providing substrate) and indirectly (by altering the anabolic hormonal milieu) increase muscle protein synthesis (for review see tessari and co-workers68 ). commercially, whey protein is marketed as a superior protein by manufacturers not only due to its high-quality protein, but also due to its bio-availability and ease of dispersion in supplements and bars. compared with other protein sources, whey has been found to contain a higher complement of essential amino acids (eaas) and branched-chain amino acids (bcaas), and to result in greater biological value in humans.38 additionally, whey protein contains more cysteine than casein. cysteine is considered important for glutathione (potent antioxidant) production.12 it is due to this characteristic that it is hypothesised that the ingestion of whey protein post-exercise may protect against exerciseinduced free radical damage. though a number of studies (mostly done on animals) have demonstrated positive immune system benefits and antioxidant action with whey protein supplementation, these effects remain to be proven in physically active human populations. soy protein also offers a high-quality protein, which is equivalent to casein and egg protein78 and may therefore also contribute to protein synthesis if ingested post-exercise. additionally because of its high content of genistein and other phytochemicals, soy may have advantages in improving post-exercise recovery by increasing its antioxidant potential which could attenuate muscle breakdown.3 research investigating these possible effects during and post-exercise by evaluating skeletal muscle repair, oxidative function, antioxidant mechanisms, and immune function are, however, limited. two studies in athletes demonstrated reduced exercise-induced antioxidant stress and muscle damage after consumption of a soy beverage post-exercise.3,62 single amino acids and amino acid mixtures it has been suggested that supplementation of single amino acids or amino acid mixtures may attenuate the hormonal milieu (e.g. stimulate insulin and growth hormone release) with subsequent anabolic effects on protein metabolism,68 and/or directly stimulate the rate of muscle repair compared with the ingestion of intact protein.35 in vitro studies have shown that particularly leucine, phenylalanine, arginine and glutamine have powerful stimulating effects on insulin release by pancreatic β-cells.7 floyd and co-workers20 reported that intravenous injection of 30 g of arginine in humans resulted in a similar insulin response as found with the injection of a 30 g amino acids mixture (arginine, lysine, phehylalanine, leucine, valine, methionine, histidine, isoleucine, threonine, and tryptophane). in contrast, van loon and co-workers73 demonstrated that oral ingestion of a large dose of arginine (0.4 g/kg bw/hour) was not effective in increasing plasma arginine or insulin concentrations. this was probably due to poor intestinal absorption of arginine due to severe diarrhoea that was elicited after ingestion.73 these results indicate that oral administration of large doses of arginine (and perhaps also other single amino acids) to stimulate growth hormone release and muscle anabolism should be practised with caution and is best avoided. blomstrand and saltin10 investigated the influence of a bcaa supplement (150 ml containing 45% leucine, 30% valine, 25% isoleucine) given 15 minutes before exercise, at 15-minute intervals during 1 hour of 1-legged exercise and at 15, 30, 60 and 90 minutes of recovery on muscle protein metabolism. they found that the supplement had a proteinsparing effect during recovery, which seemed to be insulindependent. results from other studies suggest that the protein-sparing effect could have been attributed to a decrease in the rate of protein degradation.17,47 in an earlier study, blomstrand and newsholme9 showed that the ingestion of 7.5 g bcaa during a 30 km cross-country race or full marathon decreased the net rate of exercise-induced protein degradation. possible mechanisms proposed by coombes and mcnaughton17 include: (i) bcaas increase anabolism and decrease catabolism, thus there is less damage to proteins associated with cell membranes; (ii) bcaas increase sensitivity of muscle to anabolic actions of insulin, thereby increasing protein synthesis; (iii) bcaas increase their own oxidation, thus limiting muscle damage; and (iv) bcaas suppress degradation during and after sustained exercise via alpha-ketoisocaproate (kic). bcaas can increase kic concentration which inhibits muscle proteolysis in vitro, thereby contributing to a decrease in degradation.17 no influence on exercise-induced hormonal response has, however, been found after 1 week of high-volume weight training and ingestion of 2.4 g amino acid supplement prior to each meal, as well as 2.1 g bcaa supplement prior to each workout session for 1 week.21 the ingestion of a large single dose (~ 300 mg/kg bw) of bcaa ingested 15 30 minutes before and/or during exercise has been shown to increase ammonia production during exercise.43 after a series of observations brouns and coworkers13 hypothesised that high intramuscular ammonia concentration may be related to the aetiology of muscle exhaustion during prolonged, strenuous endurance exercise. other studies found no effect of bcaa ingestion on ammonia production, especially with low amounts (< 100 mg/kg bw) ingested as multiple smaller doses before or during exercise.8,46 enhanced responsiveness of the pituitary corticotrophin and gonadotropin secretory cells to their releasing hormones (e.g. growth hormone) has been shown 60 minutes after the 36 sports medicine vol 16 no.2 2004 ingestion of an amino acid mixture (100 mg arginine/kg bw + 80 mg ornithine/kg bw + 140 mg bcaa + 10 g glucose/serving).18 an earlier study36 showed no influence on growth hormone concentration after the ingestion of three different amino acid drinks according to manufacturer's instructions (drink a = 2.4 g l-arginine/l-lysine/serving; drink b = 1.1 g l-ornithine, 750 mg pyridoxine hcl, 125 mg ascorbic acid; drink c = 20 g bovril: 7.8 g protein, 580 mg cho, 146 kj) after an 8-hour fast. it can be concluded that growth hormone secretion may be affected by the type of amino acid, its dosage and the specific combination of amino acids ingested, but more research is needed to confirm these findings. the question of eaa compared with mixed amino acid (maa) supplements on protein synthesis has also sparked some interest. tipton and co-workers69 found that the ingestion of either a maa (40 g/serving) or eaa (40 g/serving) supplement after a resistance exercise protocol led to similar net positive protein balance compared with a negative protein balance with placebo ingestion. they therefore showed an anabolic response post-exercise, with or without eaa, which was also comparable to intravenous amino acid infusions. a more recent study11 found a significantly higher net muscle protein balance response after a resistance exercise protocol when an eaa (6 g/serving) supplement was ingested post-exercise compared with a non-eaa (3 g eaa + 3 g non-eaa/serving) supplement. it can be concluded from these studies that there might be a threshold for the amount of eaa needed to stimulate protein synthesis and that noneaa is not necessary to achieve protein balance. glutamine glutamine is a major fuel source to the intestinal wall (brush border) and due to the high turnover of these cells they need a continual supply of amino acids for protein synthesis.77 thus, cells of the intestine may be preferentially supplied with amino acids for oxidation and protein synthesis at the expense of skeletal muscle protein.28 it is therefore hypothesised that providing dietary glutamine can 'spare' intramuscular glutamine, while supplying the intestine with needed glutamine. this would contribute to a decrease in proteolysis secondary to lowered blood glutamine concentrations. hankard and co-workers,25 however, found no change in glutamine release from proteolysis after a glutamine infusion study done at rest, whilst demonstrating an increase in protein synthesis during glutamine infusion at rest.26 it therefore seems that glutamine supplementation may have an anabolic effect based on its influence on protein synthesis. additionally, glutamine has been reclassified as a conditionally essential amino acid during certain stressful conditions (including strenuous exercise).24 most studies investigating the effect of glutamine on muscle protein metabolism have, however, been done in the clinical setting. thus, studies investigating the direct influence of glutamine supplementation on muscle protein synthesis in athletes are limited. welbourne75 showed an increased plasma growth hormone concentration 90 minutes after ingestion of 2 g glutamine over a 20-minute period. whether chronic ingestion of glutamine will result in a continued increase is, however, not known. glutamine supplementation (0.35 g/kg bw/day for 14 days) in wrestlers consuming a hypocaloric diet resulted in the maintenance of a positive nitrogen balance, while the placebo group was in a negative nitrogen balance at the end of the supplementation period.61 decreases in plasma glutamine concentrations has been shown after strenuous prolonged exercise, which could influence immune system regulation59 since glutamine is an important fuel source for lymphocytes and macrophages.2 decreased glutamine concentrations have also been found in athletes suffering from 'over-trained syndrome'.48 the reduced glutamine concentrations seen after prolonged endurance-type exercise have been proposed to be a result of increased glutamine use by cells of the immune system.48 the effects of glutamine supplementation in endurance athletes on the immune system function are, however, contradicting (for review see rohde and co-workers59). thus, although glutamine supplementation to enhance immune system function is currently a popular practice amongst athletes, further scientific research is needed to establish the clinical relevance of glutamine supplementation in athletes in order to enhance immune system function. β-hydroxy β-methylbutyrate (hmb) hmb is a metabolite of leucine and has been suggested to increase strength and fat free mass (ffm).49 the metabolic function and fate of hmb are not fully understood (for a detailed review see nissen and abumrad49). preliminary data suggests that hmb may be part of some structural component within tissues or membranes.49 the proposed mechanism of increased strength and ffm is thought to be linked to hmb's anti-catabolic effects and inhibition of proteolysis.55 leucine and kic (an intermediate in leucine breakdown to hmb) have both been shown to inhibit proteolysis.49 most studies on hmb focus on its effect on ffm accretion and strength gains. the preponderance of data suggest an increase in ffm and strength with the supplementation of 1.5 3 g hmb/day for at least 3 weeks combined with ≥ 2 times/week resistance training.22,30,50,52 two clinical studies15,44 also found a decrease in protein degradation and increases in ffm when cachectic patients were supplemented with a hmb-mixture (3 g hmb + 14 g lglutamine + 14 g l-arginine/day) for 8 weeks without physical activity compared with a placebo group. knitter and co-workers32 investigated the effect of hmb supplementation (3 g hmb/day 6 weeks prior to and 4 days after a prolonged run) in endurance-trained males and females. the placebo group exhibited a significantly greater increase in creatine phosphokinase and lactate dehydrogenase activity compared with the hmb-supplemented group. these results suggest that hmb prevents exercise-induced muscle damage, which results have been supported by others.52 kreider and co-workers,33 however, found no difference in whole body anabolic/catabolic markers, body composition, muscle enzyme efflux or one repetition maximum (1-rm) in resistance-trained men after 28 days of hmb supplementation (3 or 6 g hmb/day) combined with 7 hours/week resistance training. on the other hand, panton and co-workers52 found that hmb supplementation (3 g hmb/day for 4 weeks) combined with a resistance training programme increased body strength and minimised muscle damage regardless of sports medicine vol 16 no.2 2004 37 gender or training status. a possible reason for discrepancy in results could be that training loads were inadequate in the study by kreider and co-workers,33 since subjects' resistance training was not monitored on a day-by-day training basis. additionally, lack of significance might have been due to small statistical power since there were small numbers of subjects per treatment group. lastly, the combination of hmb and creatine (20 g creatine + 3 g hmb/day for 7 days followed by 10 g creatine + 3 g hmb/day for 14 days) during a weight-training programme has also been shown to increase body strength and ffm and their effects seem to be additive.30 it is, however, important to note that most studies that found a positive relationship between hmb and ffm or strength were done by the same research group. furthermore, it is important to note that the majority of studies that showed an increase in ffm22,30 and/or strength22,30,52 were done on untrained subjects embarking on a training programme. those studies done on trained individuals33,51,57,65 found no effect of hmb supplementation on measures of ffm and strength. creatine creatine is a naturally occurring compound derived from the amino acids glycine, arginine, and methionine.4 the daily requirement of creatine is approximately 2 3 g and can be obtained exogenously from the diet, primarily meat and fish, while the remainder is synthesised endogenously.4 numerous studies have demonstrated that creatine supplementation is associated with an enhanced ability to perform repeated bouts of high-intensity exercise interspersed by short recovery periods mainly attributed to increased adenosine triphosphate (atp) re-phosphorylation (for review see beduschi4). creatine supplementation typically consists of a loading phase (2 5 days) in which 20 g creatine/day (4 x 5 g doses spread over the course of a day) is ingested, followed by a maintenance phase (≥ 3 days) in which 2 5 g creatine/day is ingested.67 it is hypothesised that creatine supplementation can be beneficial during the recovery phase in terms of protein synthesis and gains in ffm. many studies have reported a significant increase in ffm, ranging from 1 to 2.2 kg with creatine supplementation.5,34,67 the gain in body mass has traditionally mainly been attributed to water retention within the muscle due to increased cellular osmolarity.31,34 however, it has been suggested that creatine ingestion may also stimulate myofibrillar protein synthesis27,67,76 and/or inhibit protein breakdown53 and thereby increase ffm. another proposed mechanism includes an increased resynthesis of atp which could allow for an increased training capacity and higher quality exercise bouts, thereby increasing exercise-induced stimulation of muscle protein synthesis. additionally, creatine may play a role in glycogen synthesis, mediated by drawing water via an osmotic effect into the intracellular compartment.5,74 it is, however, important to note that some people might be non-responders to creatine supplementation and therefore not gain any benefit from it.39 the reason for this is not clear but might be linked to habitual dietary habits (fish and meat consumption), as well as muscle fibre composition.39 combination of protein with other substrates cho and protein the insulinotrophic and endocrine effects of combined protein and cho may attenuate muscle breakdown64 and increase muscle protein synthesis.58 chandler and co-workers14 found significantly higher plasma insulin levels postexercise when experienced male weight lifters consumed isocaloric cho (1.5 g cho/kg bw/serving) and cho-protein (1.06 g cho + 0.41 g protein/kg bw/serving) supplements compared with an isocaloric protein only (1.38 g protein/kg bw/serving), as well as a control supplement. furthermore, growth hormone levels were significantly greater with the cho-protein supplement at 6 hours post-exercise. the optimal cho:protein ratio for muscle repair and anabolic hormonal milieu seem to be 4-7:1.58 combining protein, cho and fat roy and co-workers63 found that the addition of fat to a cho and protein meal did not influence post-exercise muscle repair negatively. furthermore, positive correlations have been shown between testosterone levels and the percentage of overall dietary fat, mono-unsaturated and saturated fat. however, a negative correlation with polyunsaturated-to-saturated fatty acid ratio was reported.45 practical considerations with protein ingestion increasing the protein (and fat) content of a meal/beverage may decrease gastric emptying and subsequent intestinal absorption of nutrients.29 this is of practical importance when including protein in the before, during, or post-exercise cho beverage seeing that it may ultimately delay cho (glucose) absorption and availability for energy production and the regeneration of muscle glycogen stores, both critical factors for increased exercise performance and post-exercise recovery (as discussed earlier). additionally, delayed gastric emptying may contribute to feelings of stomach discomfort (fullness or bloatedness), which might dampen appetite and decrease the volume of food, and more specifically, the amount of cho ingested in the post-exercise recovery period. as discussed earlier, when multiple exercise or competition sessions are performed within a day and recovery time is limited, decreased cho intake and availability, as well as stomach discomfort may decrease the rate of recovery post-exercise and/or directly decrease exercise performance. post-exercise protein ingestion should ideally not exceed 0.2 0.4 g/kg bw/hour. furthermore, oral ingestion of single amino acids in large doses should be avoided as it may cause gastrointestinal upset and diarrhoea.73 lastly, long-term excessive protein and/or amino acid intake (> 2 g/kg bw/day) may contribute to overweight (especially if overall calorie intake is excessive), as well as increased urinary calcium losses, which could lead to the development of osteoporosis if calcium intake is inadequate.23 other adverse effects include hypotension, tumour stimulation, mental retardation, and fatty liver (for detailed review see garlick23). 38 sports medicine vol 16 no.2 2004 conclusions although athletes have a higher protein need than sedentary individuals to maintain a positive nitrogen balance, ingesting more protein (> 2 g/kg bw/day) than is needed to maintain this balance will not result in further enhancements in muscle repair and adaptation. in fact, excessive protein and/or amino acid intake may contribute to various adverse effects and gastro-intestinal upsets. the sooner protein is ingested post-exercise the faster the body is shifted into an anabolic environment, which is important for protein synthesis and adaptation. it seems that protein hydrolysates result in higher insulin secretions than intact protein. furthermore adding leucine and phenylalanine to a protein hydrolysate could cause even greater insulin secretion, thereby creating an anabolic hormonal milieu. the insulinotrophic and endocrine effects of combined protein and cho ingestion (~0.8 g cho/kg bw/hour + 0.2 0.4 g protein/kg bw/hour) may reduce muscle breakdown and increase muscle protein synthesis in the post-exercise period. the effect of glutamine supplementation on immune function still needs further investigation to establish its clinical relevance. hmb supplementation seems to increase ffm and strength when untrained individuals start a training programme, with little proven benefits in trained individuals. creatine supplementation seems to be beneficial during the recovery phase in terms of protein synthesis, gains in ffm and glycogen storage. practical recommendations it is concluded from part i and part ii of this contribution that macronutrient manipulation is a potential strategy to enhance recovery and the adaptation process post-exercise. it is, however, important to keep dietary advice individualised considering the complexity in which the endocrine system regulates cell function, the diverse mechanisms that control homeostasis, as well as genetic variability. considering the relevant literature discussed in parts i and ii of this article, the following recommendations for enhanced muscle repair and muscle glycogen storage postexercise are made: short ≤ 6 hours) recovery period • ingest 1 1.5 g high gi cho/kg bw immediately postexercise and at 15 60-minute intervals for 3 4 hours thereafter, or 0.8 g high gi cho + 0.2 0.4 g protein/kg bw immediately post-exercise and at 15 60-minute intervals for 3 4 hours thereafter. practice with various amounts and combinations in order to establish individual tolerance and stomach comfort. • aim at an overall ingestion of 7 10 g cho/kg bw within a 24-hour period, especially when participating in multiday competition events. • do not exceed 2 g protein/kg bw/day. • opt for protein hydrolysates with added leucine and phenylalanine. • limit dietary fat intake since it could lower the gi of the cho food and hence delay gastric emptying and the absorption and supply of nutrients to the muscle. longer (> 6 hours) recovery period • ingest 6 8 g low or high gi cho/kg bw/day for a moderate-intensity training schedule. • ingest 7 10 g low and/or high gi cho/kg bw/day for a strenuous or prolonged training or competition schedule, especially when participating in strenuous multi-day competition events. • ingest 1.2 1.8 g protein/kg bw/day for a resistance and/or endurance exercise training schedule. • do not exceed 2 g protein/kg bw/day. • athletes training at altitude can increase protein intake to 2.2 g protein/kg bw/day. • the addition of fat to a meal or supplement does not have any negative impact as long as total amount of cho and protein ingested are sufficient and a favourable body fat is maintained. • when using creatine supplementation a loading phase may be followed consisting of 20 g creatine monohydrate powder/day for 3 5 days. this 20 g dose should be divided into 4 x 5 g dosages, spread out over the course of a day. then, proceed to the maintenance phase consisting of ingesting a single dose of 2 5 g creatine/day. however, employing a loading phase is not critical or necessary. the creatine monohydrate is better absorbed when mixed into a high gi cho beverage such as a cho sports drink (providing ~30 g of a high gi cho source for every 5 g creatine ingested). • if embarking on a training programme, the addition of 1.5 3 g hmb/day to creatine supplementation could contribute to further increases in strength and ffm. • the assistance of a sports dietitian may be valuable to 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training on myosin heavy chain expression. med sci sports exerc 2001; 33: 167481. 77. windmueller hg, spaeth ae. uptake and metabolism of plasma glutamine by the small intestine. nutr rev 1990; 48: 310-2. 78. young vr. soy protein in relation to human protein and amino acid nutrition. j am diet assoc 1991; 91: 828-35. erratum an unintentional error resulted in the degrees for t h kruger, m f coetsee and s davies (south african journal of sports medicine 2004; 16: 33) being listed incorrectly. their correct qualifications are: t h kruger (bsc hons human movement science (biokinetics), msc (human movement science)) m f coetsee (ma (physical education), phd) s davies (b hum hons (london univ), ma (human movement studies), dphil 18 sajsm vol 18 no. 1 2006 landing badly from a jump during sporting activities is one of the common injury mechanisms leading to lower limb injuries.24 landing badly refers inadequate lower limb control resulting in torsion of the knee or falling which may strain the knee soft tissue structures and lead to injury. identifying and understanding biomechanical risk factors when a player lands from a jump could aid in the development of preventive programmes.40 reportedly basketball has the highest rate of serious knee injuries among non-contact sports.18 landing badly often results in more serious knee injuries measured by time lost from play or medical management.18,25 competitive adolescent basketball players in cape town reported that 41% of the knee injuries sustained over one season were related to landing badly from a jump.24 this finding concurs with similar international studies.18,25,39 landing is a complex action and requires the player to coordinate upper body, trunk and lower limb movements, absorb forces imposed on the body and maintain hip, knee and ankle stability during the movement execution.23 joint stability refers to a joint remaining or returning to proper alignment through equalisation of forces in the presence of forces that would normally change the state or condition of the joint and is critical in preventing injury to the knee joint structures.26,35 static joint stabilisers include the ligaments, joint capsules, cartilage, bone and joint shape.21 dynamic joint stability stems from neuromuscular control mechanisms.21 injury occurs to the static and dynamic restraints when the forces imposed on these systems exceed the mechanical threshold.21 when a player lands from a jump, biomechanical factors that could compromise joint stability include ground reaction forces, joint position or angles, joint moments and work. the aim of this systematic review was to systematically assess the literature reporting on the biomechanical knee injury risk factors when an individual lands from a jump. this review also evaluated what has been written on landing techniques in order to identify shortfalls in the published literature that could be applied in future landing analysis studies. the objectives of this review were to: (i) appraise information from biomechanical studies of landing published from 1990 to 2003; (ii) appraise methodological rigor of the biomechanical studies of landing published from 1990 to 2003; (iii) review the testing protocol employed in published studies; (iv) ascertain the populations commonly included in biomechanical landing studies; (v) review risk factors identified by previous studies; and (vi) identify shortcomings of published studies of landing biomechanics. review article biomechanical factors associated with the risk of knee injury when landing from a jump q louw (phd)1 k grimmer (phd)2 1department of physiotherapy, stellenbosch university, w cape 2centre of allied health evidence, university of south australia correspondence: q louw department of physiotherapy stellenbosch university po box 19063 tel: 021-938 9300 fax: 021-931 1252 e-mail: qalouw@sun.ac.za abstract objectives. to systematically assess the literature investigating biomechanical knee injury risk factors when an individual lands from a jump. data sources. four electronic databases were searched for peer-reviewed english journals containing landing biomechanical studies published over 14 years (1990 2003). study selection. publications describing research into knee joint kinetics and/or kinematics when landing from a jump were included. a total of 26 eligible articles met the inclusion criteria. data extraction. a review of the 26 eligible studies was undertaken to describe the key study components including the study aims, sample populations, measurement tools, measurement procedures and knee risk factors. methodological quality was scored using the crombie checklist and pedro scale. data synthesis. the methodological quality of the studies reviewed was fair. information on risk factors was variable. one proposed risk factor, landing with the knee in a relatively more extended position, may increase injury risk. validity was compromised when the landing action was isolated by studying drop-jumping instead of the whole landing task. results of reviewed studies were potentially confounded by a number of factors. conclusion. high-level evidence for biomechanical knee injury risk factors when landing from a jump is lacking and it is difficult to draw conclusions regarding knee injury risk factors when landing. however, the published research reviewed provides important information on injury causality and theories to direct future studies. further research should be directed towards younger populations using valid testing protocols applicable to real life scenarios. methodology level of evidence the hierarchical system of research design evidence as described by sackett et al.36 was used to determine the levels of research evidence in the published literature. search strategy databases available at the university of south australia were searched for peer-reviewed journals with papers on landing biomechanical studies. these databases included medline, cinahl, current contents and sport discus. the following key words were used: (i) landing biomechanics; (ii) landing and jump; (iii) jump landing and biomechanics; (iv) forces, landing and jump; (v) kinematics and/or kinetics, landing and jump; and (vi) mechanics, landing and jump. inclusion criteria peer-reviewed english language publications since 1990 describing research into knee joint kinetics and/or kinematics when landing from a jump were included. the search was limited from 1990 to 2003 as the last 14 years of literature provided evidence from a decade of research, as well as the most recent research findings. exclusion criteria research published prior to 1990 was excluded, unless it was a landmark study (cited by many other authors after 1990). review papers were excluded. research describing the biomechanical aspects of internal joint forces was not included in this review. studies of landing in recreational activities such as rope jumping and general functional activities were also excluded. methodological quality the crombie checklist4 was used to appraise the case-control and observational studies and the pedro scale was used to appraise randomised controlled trials.32 the 11 criteria of the pedro scale included: (i) eligibility criteria; (ii) random allocation of subjects; (iii) concealed allocation of subjects; (iv) prognostic indicators of the groups were similar at baseline; (v) blinding of all subjects; (vi) blinding of all therapists who administered the therapy; (vii) blinding of all assessors who measured at least 1 key outcome; (viii) measures of key outcomes obtained from 85% of subjects; (ix) all subjects for whom outcome measures were available received the treatment or control condition as allocated; (x) the results of between-group statistical comparisons reported for at least 1 key outcome; and (xi) the study provides both point measures and measures of variability for at least 1 key outcome. results database search results the extensive search yielded 920 hits. after removal of duplicate titles and those that did not meet the inclusion criteria, the full text versions of 26 articles were reviewed. the database search results are presented in table i. level of evidence according to sackett’s hierarchy of evidence 3 papers reported randomised controlled trials28,31,33 and thus present level 2a evidence.36 twenty-three (88%) of the studies present level 3 evidence. thirteen observational and 10 casecontrol studies were reviewed. methodological quality the methodological quality of the studies was fair. table ii presents the results of the methodological quality of the randomised controlled studies. the average score of the observational studies was 67%. the average score of the case-control studies was 72% and the 3 randomised controlled trials had an average score of 55%. fig. 1. graphically summarises the number of case-control and observational studies that met each of the 12 methodological criteria assessed by the crombie checklist. none of table i. results of search strategy search terms 1-6 excluded excluded on no of articles hits 1 2 3 4 5 6 total hits duplicates eligibility retained medline 124 81 2 32 18 3 260 27 214 19 cinahl 30 29 0 16 13 1 89 26 60 3 current contents 32 79 1 36 18 4 170 26 142 2 sport discus 237 111 0 37 21 3 401 26 374 1 reference lists 1 total 26 table ii. appraisal results of randomised trials (scoring tool: pedro scale) criterion 1 2 3 4 5 6 7 8 9 10 11 score mcnair and prapavessis27 y y n n n n y y y y y 7/11 mcnair and marshall29 y y n n n n n y y y y 6/11 onate et al.31 y y n n n n n n y y y 5/11 sajsm vol 18 no. 1 2006 19 20 sajsm vol 18 no. 1 2006 the studies met criterion 6 which assessed the reliability and validity of the measurements. criterion 11 assessed whether there could be confounding and none of studies adequately controlled for confounding. only 8% of the studies justified the sample size (criterion 3). aims of published studies and clarity of research questions the aims of published studies can be divided into 3 categories: (i) analysis of landing technique in uninjured individuals; (ii) factors influencing kinetics and kinematics when landing; and (iii) intra-subject variability of performance. eight of the 13 studies published between 1990 and 1999 aimed to analyse landing technique and provide baseline information on landing biomechanics for future studies.1,5,7,8,19,30,38,41 factors influencing lower limb kinetics and kinematics when landing were evaluated by 13 of the 26 studies reviewed. only 4 of the 13 studies were published before 1999. to summarise the injury risk factors, factors suggested by published studies to reduce knee injury risk were considered ‘positive factors’ and those factors likely to increase injury risk were considered ‘negative factors’. results of these studies indicated that plyometric training14 and augmented verbal feedback positively affect lower limb kinetics and kinematics.3,27 factors found to negatively influence lower limb kinetics and kinematics included female gender, cryotherapy, pubescent stage and injury.2,5,11,12,13,15, 17, 22,30,34 two published studies on within-participant variability in biomechanical parameters when a subject repeats the same task more than once were reviewed. both studies were published after the year 2000.16,37 this may indicate that intrasubject variability emerged as a factor to consider in injury occurrence from the results of earlier studies. the published studies hypothesised that increased intra-subject variability in biomechanical parameters may reduce the stress placed on a specific joint structure and thereby reduce the chances of injury to that structure due to repeated strain.13 both studies13,37 provide level 3 evidence and the findings were inconclusive since the researchers were unable to demonstrate a consistent relationship between intra-subject variability and injury occurrence. further studies into intra-subject variability and more appropriate statistical methods to analyse the data are required. the 3 randomised controlled trials aimed to identify mechanisms of reducing ground reaction forces when landing from a jump by using verbal and auditory feedback.28,31,33 sample descriptions the sample sizes of the published studies varied between 3 and 91 participants. although the mean sample size was 32, the standard deviation was large (sd 47). fifteen of the 26 studies reviewed included 20 or less subjects. seven studies included between 20 and 50 subjects and only 3 studies included more than 50 subjects. only 2 studies justified the sample size employed in the study.3,15 table iii indicates that males were more frequently studied than females. females were only included in 17 studies, while males were included in 22 studies (table iii). considering that the prevalence of serious knee injuries such as anterior cruciate injuries is more common among females than males, more studies should include female participants.14 three of the 13 studies including males and females aimed to assess gender differences in lower limb biomechanics when landing.11,14,22 these studies found that females demonstrated increased lower limb injury risk compared with males. results of a survey conducted in cape town, however, indicated no significant gender difference in sustaining a knee injury between male and female adolescent basketball players (odd’s ratio: 1.2, 95% confidence intervals (cis): 0.7 1.9).24 the average age of subjects was 23 years. three studies included subjects under the age of 20 years.7,14,33 the results indicate the lack of information currently available on landing biomechanics among adolescent individuals. injury status of published studies six of the 26 studies reviewed included injured participants. three studies included anterior cruciate ligament (acl)injured players.5,12,29 one study included players who had a history of overuse injury,16 1 study included players suffering from patellar tendonitis34 and the remaining study included subjects with ankle joint instability. the mean age of subjects included in these studies was 26.5 years (sd 1.8). currently there is therefore no biomechanical landing information on lower limb kinetics and kinematics of injured adolescents when landing from a jump. table iv provides a summary of the injury status of participants included in published studies. table iii. gender inclusion in published studies gender inclusion no of studies males only1,2,8,12,17,19,30,34,41 9 females only3,5,7,13 4 males and females5,11,14-16,22,27-29,31,33,37,38 13 fig. 1. summary of appraisal scores. type of sporting activity table v illustrates the type of sports and recreational activity status of samples. although 9 studies included subjects participating in general jump sports, 3 studies specifically stated that basketball players were included. one study included only basketball players.11 level of play table vi indicated the 7 terms employed by published studies to describe the level of play. variations in defining level of play hamper comparison of studies. thirteen of the 26 studies reviewed used subjects participating only at recreational level and only 3 studies involved only elite athletes (table vi). matching criteria for subjects in case control studies ten case control studies were identified. only 1 of these studies included adolescents and all subjects in this study were uninjured.14 five of the case control studies included injured and uninjured subjects.2,5,16,29,34 one author did not clearly indicate whether subjects were grouped or individually matched.29 only 1 of these studies individually matched the injured and uninjured subjects.5 individual matching is a more effective method of controlling for confounding because the effect of confounding factors is reduced and the results are therefore more robust.5 testing procedure the data collection procedures of published studies may require further scrutiny before extrapolating the results into practice. sixteen of the 26 studies reviewed isolated the landing action by studying drop-jumping instead of the whole landing task (that also includes a take-off phase). measurement tools one of the most common parameters assessed in studies analysing landing is ground reaction force (grf), considered to be a risk factor for lower limb injury.29 twenty-one of the studies (80%) reviewed in this aspect of the research project utilised a force plate to measure grfs. measurement of lower limb kinetics and kinematics using single cameras was done in 5 studies. one study used a tracking device and 1 used a potentiometer. an electrogoniometer was only utilised in 1 of the papers reviewed. three-dimensional motion analysis equipment was used in 5 studies. knee injury risk factors landing with the knee in a more extended position (less than 45º) results in reduced energy absorption and may predispose individuals to injury.2,5,8,13,15,41 on the other hand, 1 study stated that deep knee flexion angles (more than 90º) when landing predisposed volleyball players to patellar tendonitis.34 it is important to note that there are differences in the method of knee angle measurement in the above studies and that this will influence the interpretation and clinical application of the results. the most appropriate knee flexion angle when landing and the relationship between the knee flexion angle and injury occurrence must therefore be explored further. eccentric knee control to maximise energy absorption is hypothesised to be critical to knee function when landing.5, 41 eccentric knee control is thought to be important in maintaining knee stability as the knee joint flexes and the player has to control lowering the body. poor dynamic stability will result in torsional forces at the knee joint, increasing injury risk of knee joint structures when landing.20 large grfs when landing are also postulated to increase injury risk. landing height, reduced knee flexion, anterior tibial translation, vastus medialis activity, peak adduction and abduction moments and heel-toe landing are believed to result in relatively higher grfs.1,8,14,29 table vii presents a summary of knee injury risk factors. discussion to the best of our knowledge this is the first systematic review of biomechanical knee injury risk factors when an individual lands from a jump. we searched the primary databases indexing biomechanical peer-review publications reporting on this topic. date limits were set as the methodtable iv. injury status of participants in published studies number of studies uninjured1,3,5,7,8,11,13-15,17,19,22,28-31,37,38,41 19 injured12 1 injured and uninjured2,5,16,29,34 5 not mentioned27 1 table v. type of sporting activity included in published studies recreational activity number of studies basketball, volleyball and soccer22 1 basketball and volleyball5 1 gymnastics30 1 basketball11 1 jump/landing sports1,5,8,13,16,41 6 volleyball7,14,34 3 no jump sports28 1 netball3 1 general sports2,12,15,17,19,27,29,31,33,37,38 11 table vi. level of play level of play no. of studies elite3,7,34 3 elite and recreational30 1 recreational1,2,5,8,13,15,16,22,28,31,37,38,41 13 recreation and competitive27,29,33 2 college level5,11,19 3 school level14 1 not stated/ not applicable12,17,31 3 sajsm vol 18 no. 1 2006 21 ological quality of studies improved over time, especially over the mid-1990s.23 the review included a range of different study design types – 3 randomised controlled studies (11%), 13 observational (50%) and 10 case-control (39%) studies. the methodological quality of the studies was only fair and it is thus difficult to draw conclusions regarding knee injury risk factors. the generalisability of the study findings is compromised by unjustified sample sizes and sample recruitment methods. sample sizes of less than 30 subjects are regarded as small since the power is substantially reduced and about 60% of the studies reviewed included 20 or fewer subjects. one reason for small sample sizes may be time-consuming practical implications when collecting and processing biomechanical data. further technological improvements may reduce data collection and processing time, enabling researchers to recruit larger samples that can be representative of a population. no study justified the reliability and validity of the measurement equipment. establishing reliability of biomechanical equipment is a voluminous task and thus impractical for most researchers to undertake before they collect data. establishing the reliability and validity of measurement tools may also not be within the research scope of research into clinical application of biomechanics. however it is important for researchers to understand the degree of reliability of the equipment by referring to published reports into reliability of their measurement tools. basketball arguably has the highest rate of knee injuries and may be one of the fastest growing sports in south africa.24 this review highlights the shortage of research into basketball to investigate biomechanical factors predisposing players to knee injuries. each sport has specific characteristics and game dynamics and therefore further research to investigate biomechanical risk factors among basketball players is warranted. this review of published biomechanical information since 1990 indicated no information regarding the landing strategies of knee-injured adolescents. developmental stage influences neuromuscular control and consequently the landing strategies demonstrated by injured adolescents may differ from the technique demonstrated by injured adults.13 the landing strategies of uninjured adolescents are biomechanically less safe than those of uninjured adults. adolescents presenting with a knee injury may further compromise joint stability when landing from a jump. younger populations should thus be considered in future studies. most of the studies (61%) isolated the analysis of landing from drop jumping. a recent study aimed to compare the landing phase of a drop-jump movement with a volleyball spike-jump movement among volleyball players.10 results indicated that the 2 tasks differed significantly with respect to grfs, lower limb kinematics and muscle activation synchrony. therefore it may not be valid to modify the landing task to only the drop-landing phase and this must be considered when comparing results with those from studies that involved the whole landing task. five (19%) of the 26 studies reported sport-specific jumps. this highlights the lack of research into landing as a whole and the limitations for clinical application. 22 sajsm vol 18 no. 1 2006 table vii. knee injury risk factors identified lower knee eccentric angular velocity is seen in patients with an old rupture of the acl12 grf increase with landing height and knee extension8 landing in less knee flexion results in less energy absorption by the muscular system and more stress on the skeletal structures5 magnitude of grf is positively correlated to anterior tibial accelerations, increasing acl strain 29 vastus medialis activity is an important predictor of grf1 peak adduction and abduction moments were predictors of grf14 deep knee flexion angles, high grfs, rates of loading the extensor mechanisms and tibial external torsional moment predicted patellar tendonitis.34 heel-toe landing results in higher grf compared with toe-heel landing heel-toe landing leads to higher hip and knee negative power and work and less energy absorption by the plantarflexors19 the relationship between variability of selected joint moments and injury proneness is unclear16 knee extensors are consistent contributors to energy dissipation across different landing techniques and heights. eccentric strength of the knee extensors critical to knee function41 effective instructions and auditory cues could reduce grf28 individuals with ankle instability compensate by increasing ankle dorsiflexion and knee flexion pre-andpost landing2 initial flexion impact angle was reduced in females compared with males15 activity post cryotherapy does not predispose to injury17 augmented feedback can reduce landing forces31 acl reconstructed group had reduced hip flexion, reductions in peak hip and knee negative power and reduced hip extensor energy absorption5 reduced and poorly controlled knee flexion among females compared with males22 verbal instructions increased knee flexion, but not earlier hamstring activation3 under non-fatigued and fatigued conditions, no difference in knee flexion and muscle activity was seen between males and females11 postpubescent females landed with the knee more extended, and had greater extensor moments and power that plays a role in increased risk of injury13 acl = anterior cruciate ligament; grf = ground reaction force. sajsm vol 18 no. 1 2006 23 this review indicated a wide range of biomechanical knee injury risk factors. inadequate knee flexion angles when landing was nominated by 23% of the studies as a likely knee injury risk factor when landing.2,5,13,15,22,34 the degree of knee flexion may be an indication of the ability of the individual to control the eccentric knee movement and absorb shock, contributing towards joint stability and consequent injury prevention.23 however the variability in study samples and other methodological shortcomings hinders general acceptance among clinicians of knee flexion as a primary risk factor in knee injury. the results of reviewed studies are potentially confounded by a number of factors. these include subject matching, subject recruitment method, and unclear inclusion and exclusion criteria. it is not possible to generalise those review findings and to establish relationships between biomechanical parameters and pathology in the presence of confounding factors illustrated by the studies reviewed. according to sackett’s evidence hierarchy, the publications we reviewed provide level 2a (11% of studies) and level 3 (89% of studies) evidence regarding the biomechanical risk factors. although high-level evidence is lacking for biomechanical knee injury risk factors when landing from a jump, the published research reviewed provides important information on causality and theories to direct well-designed future longitudinal and randomised studies. references 1. caster b, bates b. the assessment of mechanical and neuromuscular response strategies during landing. med sci sports exerc 1995; 27: 73644. 2. caulfield b, garret m. functional instability of the ankle: differences in patterns of ankle and knee movement prior to and post landing in a single leg jump. int j sports med 2002; 23: 64-8. 3. cowling e, steele j, mcnair p. effect of verbal instructions on muscle activity and risk of injury to the anterior cruciate ligament injury during landing. br j sports med 2003; 37: 126-30. 4. crombie i. the pocket guide to critical appraisal: a handbook for health care professionals, london: bmj publishing group, 1996. 5. decker m, torry m, noonan t, riviere a, strerett w. landing adaptations after acl reconstruction. med sci sports exerc 2002; 34: 1408-13. 6. devita p, skelly w. effect of landing stiffness on joint kinetics and energetics in the lower extremity. med sci sports exerc 1992; 24: 108-15. 7. dufek j, zhang s. landing models for volleyball players. j sports med phys fitness 1996; 36: 35-42. 8. dufek j, bates b. the evaluation and prediction of impact forces during landings. med sci sports exerc 1990; 22: 370-7. 9. dufek j, bates b. biomechanical factors associated with injury during landing in jump sports. sports med 1991; 12: 326-37. 10. edwards s, steele j. is it valid to isolate the landing phase of a whole movement skill? paper presented at australian conference of science and medicine in sport, melbourne, 12 16 october 2002. 11. fagenbaum r, darling r. jump landing strategies in male and female college athletes and the implications of such strategies for anterior cruciate ligament injury. am j sports med 2003; 31: 233 40. 12. gauffin h, petterson g, tropp h. kinematic analysis of one leg hopping in patients with an old rupture of the anterior cruciate ligament. clinical biomechanics 1990; 5: 41-6. 13. hass c, schick e, chow j, tillman m, brunt d, cauraugh j. lower extremity biomechanics differ in prepubescent and post-pubescent female athletes during stride jump landings. journal of applied biomechanics 2003; 19: 139-52. 14. hewett t, stroupe a, nance t, noyes f. plyometric training in female athletes. decreased impact forces and hamstring torques. am j sports med 1996; 24: 765-73. 15. huston l, vibert b, ashton-millee j, wojtys e. gender differences in knee angle when landing from a drop jump. am j knee surg 2001; 14: 215-20. 16. james c, dufek j, bates b. effects of injury proneness and task difficulty on joint kinetic variability. med sci sports 2000; 32:1833-44. 17. jameson a, kinzey s, hallam j. lower extremity cryotherapy does not affect vertical ground reaction forces during landing. journal of sports rehabilitation 2001; 10: 132-42. 18. jones d, louw q, grimmer k. recreational and sporting injury to the adolescent knee and ankle: prevalence and causes. australian journal of physiotherapy 2000; 46: 179-88. 19. kovacs i, tihanyi j, devita p, recz l. foot placement modifies kinematics and kinetics during drop-jumping. med sci sports exerc 1999; 31: 708-15. 20. lephart s. sensorimotor system. performance and protection. paper presented at 7th olympic conference in sports sciences, athens, 7-11 october 2003. 21. lephart s. sensorimotor system part 1. physiological basis of joint stability. journal of athletic training 2002; 37: 71-9. 22. lephart s, ferris c, riemann b, myers j, fu f. gender differences in strength and lower extremity kinematics during landing. clin orthop 2002; 401: 162-9. 23. louw q. knee injury prevention among adolescent basketball players. phd thesis, university of south australia, 2004. 24. louw q, grimmer k, vaughan k. knee injury patterns among young south african basketball players. south african journal of sports medicine 2003; 15: 9-15. 25. mckay g, goldie p, payne w, oakes b, watson l. a prospective study of injuries in basketball: a total profile and comparison by gender and standard of competition. j sci med sport 2001; 4: 196-211. 26. mcnair p, wood g, marshall r. stiffness of the hamstring muscles and relationship to function in anterior cruciate deficient individuals. clinical biomechanics 1992; 7: 131-7. 27. mcnair p, prapavessis h. normative data of vertical ground reaction forces during landing from a jump. j sci med sport 1999; 2: 86-8. 28. mcnair p, prapavessis h, callender k. decreasing landing forces. br j sports med 2000; 34: 293-6. 29. mcnair p, marshall r. landing characteristics in subjects with normal and anterior cruciate ligament deficient knee joints. arch phys med rehabil 1994; 75: 584-9. 30. mcnitt-gray jl. kinetics of lower extremities during drop landing from three heights. j biomech 1993; 26: 1037-46. 31. onate j, guskiewicz k, sullivan r. augmented feedback reduces jump landing forces. j orthop sports phys ther 2001; 3: 511-7. 32. pedro scale. http://ptwww.cchs.usyd.edu.au/pedro (last accessed 1 june 2003). 33. prapavessis h, mcnair p. effects of instruction in jumping technique and experience on ground reaction forces. j orthop sports phys ther 1999; 29: 352-6. 34. richards d, ajemian s, wiley j, zernicke r. knee joint dynamics predict patellar tendonitis in elite volleyball players. am j sports med 1996; 24: 676-83. 35. riemann bl, lephart s. sensorimotor system: part 1: physiological basis of joint stability. j ath training 2002; 37: 71-9. 36. sackett d, richardson, rosenberg w, haynes r. evidence based medicine. london: oxford churchhill livingston, 2000. 37. schot p, barbara a, mueller m. within-participant variation in landing kinetics: movement behaviour trait or transient? res q exerc sport 2002; 73: 450-6. 38. schot p, bates b, dufek j. bilateral performance symmetry during drop landing: a kinetic analysis. med sci sports 1994; 26: 1153-9. 39. steele j. minimising lower limb injuries in sports. paper presented at the fifth ioc world congress in sport sciences, sydney, 31 october 5 november 1999. 40. van mechelin w. sports injury surveillance systems. sports med 1997; 24: 164-8. 41. zhang s, bates b, dufek j. contributions of lower extremity joints to energy dissipation during landings. med sci sports exerc 2000; 32: 812-9. editorial 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license entering the era of artificial intelligence (ai) in publishing the south african journal of sports medicine (sajsm) published 36 papers in 2022. fifty-eight percent of the submitted papers were not accepted. the year was spent preparing the published manuscripts from 2019 onwards for the national library of medicine’s pubmed database. it is a technically difficult task, so it was outsourced to a company in the usa which specializes in file conversions. they provided an excellent service so the sajsm will continue to use them in the future. file conversions adds another dimension to managing the journal because we have to cover the costs associated with this service. the south african sports medicine association (sasma) has been covering the costs of the journal since 1983, but the annual budget of the journal now exceeds the amount they are able to contribute. commercial partners who could contribute to the running costs of the journal were sought, but this was not successful. this has necessitated a change in the publishing model of the journal to include publication costs for the authors. a “sweet spot” cost has been calculated that will be affordable for the authors and meaningful for the journal’s budget. authors who are sasma members will get a reduced rate. the sajsm is also accepting adverts which will be displayed on the opening page of the website. this new publishing model will enable the journal to grow and be self-sustaining. it will also reduce the financial burden on sasma which has supported the journal for four decades. the sajsm has identified other challenges. for example, it is increasingly difficult to get good quality reviewers. reviewing is an altruistic job because there is no external recognition or payment. with a double-blind review, the identity of the reviewer is only known to the editorial staff. there is no reward for the reviewer, apart from the good feeling associated with making a contribution to science and the development of knowledge. also, the process of peer review is not perfect. personal biases may creep into the review and the original thoughts of the authors may get blocked or redirected by the reviewer. this is unfortunate because it contaminates the system designed to maintain the progression of knowledge. a better system of checking the quality of manuscripts before publication has not yet been devised, so this imperfect system has to be used. it is a problem all journals encounter. the sajsm has addressed the problem by offering training courses for potential reviewers. these courses teach the principles of reviewing and work on the premise that the principles of reviewing a paper can be applied to writing a manuscript. in other words, reviewers with good reviewing skills usually have good writing skills. the sajsm is also discussing how reviewers working in a health professional environment can get continuing professional development (cpd) points for completing a review. another incentive for reviewing, particularly for reviewers working in an academic environment, is to subscribe to publons. this is a website that tracks and verifies peer review reports for academics. publons has gained popularity and now has 3 000 000 subscribed reviewers. in 2017 clarivate bought publons and incorporated it into the web of science. publons produces a comprehensive report of all the reviews the subscribers have completed. reports can be downloaded and used to boost an academic cv. the sajsm is planning to automate the process of linking the reviewer’s report to publons as an incentive to reviewers. these are just some of the strategies which will be implemented to reduce the burden of reviewing. the next challenge the sajsm faces is to identify nonauthentic work which is submitted for review. to guard against this every paper submitted to the journal is submitted to ithenticate. this software checks plagiarism. in 2022 three papers were rejected before review because significant parts of them had been published previously. the challenge of detecting plagiarism is compounded by the public’s access to chatgpt, ai software released to the public in november 2022. chatgpt generates original text based on written prompts. text generated by chatgpt is not detected by ithenticate. stories abound about the miraculous things the software can do. for example, chatgpt can write well-constructed essays, personalised bedtime stories for children, poetry and lyrics for songs. perhaps the most publicised feat was the software getting a grade (b) on a wharton business school test. microsoft announced in january 2023 that it had made a ~$10 billion investment into the company openai which developed chatgpt. massive investments in technology are only made in exceptional circumstances when it is clear the product will change the trajectory of the development of society. chatgpt is such a case. there is no doubt that this software is going to have a major impact on education. there is concern among educators that students will rely on chatgpt for much of their work and many of them will. many scientists will also use chat gpt as a lazy shortcut. if the software is used as a crutch it will hinder the development of critical thinking and problem-solving skills. these skills are a prerequisite for many jobs, and scientists need these skills to answer questions and communicate the results. students and scientists without these skills will lag behind and become less competitive. a counterargument is that if chatgpt is used appropriately it can be a tool which assists in developing these skills. an analogy would be how calculators serve mathematics. when calculators became available to scholars there was concern they were going to be a threat to teaching mathematics. however, the discipline adapted and using calculators has become integral to teaching and applying mathematics. the same logic applies to scientists who try and use the chatgpt software as a quick fix to their writing and research. if the software is not used in an innovative way, the scientists will drift towards mediocrity because their work will lose the creative edge that can only come from original critical thinking. it is too early to predict how this new software will affect us. there are compelling arguments for and against it. our challenge is to remain alert for positive and negative effects and adjust accordingly. failing to do so will have many unintended consequences. mike lambert editor-in-chief s afr j sports med 2023;35:1. doi: 10.17159/2078-516x/2023/v35i1a15511 https://clarivate.com/ https://clarivate.com/webofsciencegroup/solutions/web-of-science/ https://clarivate.com/webofsciencegroup/solutions/web-of-science/ https://openai.com/blog/chatgpt/ https://www.nbcnews.com/tech/tech-news/chatgpt-passes-mba-exam-wharton-professor-rcna67036 https://www.bloomberg.com/news/articles/2023-01-23/microsoft-makes-multibillion-dollar-investment-in-openai https://www.brookings.edu/blog/education-plus-development/2023/01/09/chatgpt-educational-friend-or-foe/ https://www.brookings.edu/blog/education-plus-development/2023/01/09/chatgpt-educational-friend-or-foe/ https://www.brookings.edu/blog/education-plus-development/2023/01/09/chatgpt-educational-friend-or-foe/ http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15511 https://orcid.org/0000-0001-8979-1504 sajsm vol. 28 no. 1 2016 17 original research transformation in cricket: the black african experience ma dove,1 bsc (med) hons; ce draper,1 phd; ms taliep,2 phd; j gray,1,3 phd 1 division of exercise science and sports medicine, department of human biology, university of cape town, south africa 2 department of sports management, cape peninsular university of technology, south africa 3 cricket south africa, wanderers club, johannesburg, south africa corresponding author: ma dove (adove@mweb.co.za) background: the small number of black african (ba) cricket players progressing through the talent development pathways to the elite level has been a constant concern for cricket south africa (csa). previous attempts to accelerate the development of ba players have not produced the desired results. a description of the barriers to development is imperative for appropriate interventions. objectives: to understand the career progression of ba cricketers in south africa by investigating their and other key informants’ perceptions, and identifying factors that may influence progress to the elite level. methods: a qualitative study consisting of 23 semi-structured interviews with ba players who had succeeded at the senior level (n = 11), and key informants (n = 12), was conducted. content analysis of the data identified 92 themes, which were then aggregated into 12 categories. results: five enablers (exposure to the game, education, facilities and equipment, coaching and support networks), and five barriers (team environment, quality opportunities to compete, socio-economic factors, cricket player development pathways and leadership) were identified. two further factors (intrapersonal attributes and targets) were identified, but the differing opinions of the interviewees on the influence of these variables made it difficult to classify them. whilst all categories were perceived to contribute in the progress of ba players to the elite level, education, support networks, quality opportunities to compete, team environment and socio-economic factors were believed to be the most important. conclusion: the sustainable transformation of south african cricket appears to be not only about ensuring demographically representative teams, but also about addressing barriers affecting progress that may be experienced by all players. this study highlighted the key factors that are perceived to be specific to ba cricketers. keywords: talent pathways, ethnicity, career progression s afr j sports med 2016;28(1):17-22. doi:10.17159/2078-516x/2016/v28i1a479 since the onset of democracy in south africa in 1994, the process of transforming south african sports teams to be more demographically representative has been an ongoing challenge and debate. the transformation status report of 2013 found that transformation initiatives over the past 20 years had been mostly ineffectual and over-simplistic with quick fix strategies to achieve demographic change at the highest representative levels, which ignored the need for a multidimensional approach. furthermore, it concluded that the africanisation, (i.e. the inclusion of indigenous black africans as opposed to people of mixed race or indian descent) of sport has become an important focus of transformation in south african sport today.[1] since south africa’s return to international cricket in 1991 and the unification of the cricket bodies, firstly, as the united cricket board of south africa and currently, as cricket south africa (csa), there have been a number of transformation and development initiatives, including a variety of quotas and targets being set. yet despite these interventions and a strong cricketing culture over the past 150 years, particularly in the eastern cape,[2] only a limited number of black africans (ba) have represented south africa, and this has been largely limited to fast bowlers.[3] the lack of representation of ba players at the provincial level and above is a cause for concern. recent research has shown that there was a relative number of ba players transitioning from the u19 to the semi-professional and franchise categories. the number of ba players at national level then decreases disproportionally when players from the other ethnic groups are compared to the number of players at the high school level.[4,5] table 1 provides an overview of the racial representation of players from 2000 up to and including the 2012/13 season.[4,5] transformation is not only about having representative numbers at all levels, but also about addressing the factors influencing the identification and development of talent. factors contributing to elite sports performance is a growing area of research as individuals and nations strive to be the best. previous research has shown that talent identification and development, which lead to elite sports performance are determined by an athlete’s individual characteristics, influenced by genetics and training[6] and interaction with the macro and micro-environment.[7] csa has recognised the need to develop more players from the ba majority ethnic group to play at the highest level. identification of relevant barriers to ba progress in the game would assist csa in being able to address them going forward. the aim of this study was therefore to understand the career progression of ba cricketers in south africa, with the specific objectives of (1) investigating the perceptions of ba players and other key informants, and (2) identifying the factors influencing both the progress to, and low representation of this group of players at the elite level. methods participants and procedures a qualitative study was undertaken by conducting 23 semi-struc tured interviews. for the recruitment of participants, 22 ba male players were identified as having succeeded at the senior level. success was defined as a player who had played at least one match of any game format at the franchise (professional) level or above, or had been awarded a franchise contract. based on franchise representation, cricket discipline and availability, 15 players were approached to participate in the study. eleven players (average age of 25.3 years) made themselves available to be interviewed. four players declined the invitation to be interviewed. all players were playing at the time of the interview mailto:adove@mweb.co.za http://dx.doi.org/10.17159/2078-516x/2016/v28i1a479 18 sajsm vol. 28 no. 1 2016 and all cricket disciplines were represented. the other 12 interviews were made up of past ba players (minimum of provincial level) who were either administrators or coaches (n = 4), or administrators from diverse ethnic groups (n = 8). these participants, termed key informants, were purposively selected based on their extensive experience in the development of ba cricketers in south africa. all six cricket franchises in south africa were represented. the number of interviews was believed to be sufficient, as no new trends in information were forthcoming from participants towards the end of the interview process. each interview was conducted by the primary researcher in english, audio-recorded and lasted between 60and 90 minutes. the player interviews consisted of 40 interview guide questions covering topics such as their demographic profile, early cricketing experiences, career progression, personal attributes and skills, and their views on the representation of ba cricketers in south africa. the 28 guide questions for the key informants’ interviews covered their views on the career progression and the representation of ba players in south africa. ethical approval ethical approval for the study was obtained from the university of cape town’s faculty of health sciences’ human research ethics committee (hrec ref: 322/2012). all the participants provided informed consent and participated in the study voluntarily. participant identities have not been distinguished between players and key informants to preserve anonymity, particularly of high-profile individuals. data analysis the interviews were independently transcribed and the texts analysed using a content analytic approach,[8] with the assistance of atlas.ti qualitative data analysis software (scientific software development gmbh, berlin and germany). during the analysis, codes were defined and derived from the data to identify themes that emerged. the number of interviewees who commented on a particular theme provided insight into the importance of that theme, and the nature of the comments provided the depth to the qualitative research. quotations, rather than percentages, are presented to support the findings. combining the players and key informants interview responses, 92 themes were identified as impacting on the ability of ba players to progress through the talent pathways. these factors could be aggregated into 12 categories, five of which were perceived as enablers to progression and five as barriers. two further categories were difficult to classify because interviewees differed in their opinions of the influence of these variables (figure 1). participants acknowledged that the extent of the themes may differ between the provinces. results and discussion all participants felt that there were too few ba players at the professional level and that ba batsmen were particularly poorly represented. in addition, most participants expressed concern that there was a gap in performance, and a high dropout rate among ba players between the u19 and amateur levels. many drop outs. there have been many that have fallen; many soldiers have fallen out the bus on this long road of ours. (participant 6) table 1. progress of players from u15 to the proteas (national) level[4,5] % u15 (2004‑2010)[1] % u19 (2001‑2009) % sa u19 (2000‑2012) % semi‑pro (2012/13) % franchise (2012/13) % proteas (2012/13) w 51 53 54 46 54 57 c/i 23 24 28 33 32 37 ba 26 23 18 21 14 7 legend: w = ‘white’, i.e. caucasian or european descent; c = ‘coloured’, i.e. mixed race or mixed ancestry; i = ‘indian’, i.e. indian descent but south african in nationality; ba = ‘black african’, i.e. indigenous african descent en ab le rs b ar ri er s a d d it io n al talent identi�cation talent development elite performance exposure to game education facilities and equipment coaching support networks quality opportunities to compete intrapersonal attributes targets team environment socio-economic factors cricket player development pathway leadership fig. 1. enablers and barriers along the talent pathway i think like i said at school levels you will see there is a higher number of black african players involved, but once you get out of school then they all of a sudden disappear. maybe they’re not being followed, maybe they’re not being looked after as well as they should be after school, than they are at school and something has to be done to try to bridge that gap, but yes, to answer your question, there is a gap. (participant 3) enablers the participants identified the following influences that enabled them to progress to the professional level but commented that for the majority of ba players these factors were barriers to progress. exposure to the game the vast majority of players interviewed grew up in a township or rural area and had early exposure (6-11 years old) to the game through a relative and/or a csa talent scout. thereafter their cricket skills were developed through a structured development sajsm vol. 28 no. 1 2016 19 original research programme (sponsored by bakers biscuits) and/or at their primary schools that had varying degrees of cricket culture. while most players also participated in other sports, the majority played provincial cricket from the u13 level upwards. many of the interviewees believed that seeing the game played on television was an important factor in exposing young players to cricket as it enabled them to identify role models and learn about the game. role models provided motivation, inspiration and the belief that ba cricketers can play the game. thus the need for more ba role models is essential, particularly ba batsmen. the participants felt that with reduced cricket coverage on the national broadcaster’s services and no formal development programme for about 10 years between the bakers mini cricket programme and the current kfc-sponsored programme, there has been a decline in interest and growth of the game in ba communities leading to a reduction in numbers entering the game. and then what happened at school they wanted players to play bakers mini cricket and i said, yes why not, let me try because i know a little bit of cricket i experienced it watching it with my uncle. and then i tried it, i played it and from there i never looked back. (participant 16) […] they’re all you know looking and seeing how the game’s played and i think that that would be very detrimental to the black african cricketer in the townships not seeing it on tv […]. (participant 9) we do not have any role model batters, there are no role models so that is one of the things that i think is a weakness. (participant 17) education most of these players (n = 9) and ex-players (n = 2) had bursaries to attend a ‘cricket-oriented’ school (from 10-years-old upwards), having been identified during their younger years. they felt this was critical to their later cricket success. these schools were located outside of their immediate communities and in the former white areas, as demarcated during the apartheid era. the participants identified that the cricket culture of the school, facilities and equipment, coaching from experienced and knowledgeable coaches, a good general education, the development of life skills, and discipline were all key benefits afforded to them by this opportunity. they also mentioned that this enabled them to develop their intellectual, emotional, social and cricket intelligences on and off the field. despite initial challenges, such as language, cultural differences and home sickness, all the players concurred on the overall benefits of such programmes, and felt that the csa bursary programme should be re-invigorated by providing opportunities for talented players to attend suitable ‘cricket’ high schools. they emphasised that the monitoring of the bursary holders’ holistic progress needs to be carefully managed, as there are a number of individuals who encountered negative consequences in the past. participants highlighted the current poor quality of education in the majority of township and rural schools as potential limitations to progress as a cricketer in this environment. of particular concern were disinterested teachers, lack of coaches, poor or no facilities, few quality players with whom to compete and a limited cricket culture. while the bursary system would take players out of these areas, the players felt that cricket in these areas should be developed simultaneously. we had better education as well which was actually pretty good. i think it played a major contribution to my career. we got to learn about how to live a good life, a disciplined life, because we were at the hostel and how to make up your bed, to wear neat clothes when going to school, so it was a positive in terms of we did not only learn about cricket, but we learned about life as well which was important. (participant 22) facilities and equipment for the players interviewed, facilities and equipment were generally not considered a barrier to their cricket progress as they had access to them through the development programmes and the schools that they attended. however, it was widely acknowledged by most participants that a lack of facilities in ba communities is a barrier to the vast majority of players looking to play the sport and developing talent. while some interviewees acknowledged that facilities have been built by csa, maintenance of these facilities has been a challenge and many are now reported to be non-functional. the expense of batting equipment and lack of appropriate facilities were felt to have contributed to the small number of ba batsmen. poor or no equipment was cited as having a negative psychological effect on player performance. i think the facilities and equipment play a big role in a young, especially in a young person. i think it gives them that sort of drive to say, ‘i’m playing good cricket. (participant 18) i remember going to u15 trip, game and i had like 2 strings of padding on mine, luckily i didn’t bat, but it’s so important because it just makes players comfortable. (participant 7) coaching participants’ experience with coaches differed as they transitioned through the different levels of cricket, but all players identified the positive contribution of coaches who displayed empathy, patience, passion and support. the period between u13 and u19 was considered to be the most important period for input from experienced and knowledgeable coaches. many of the players believed that coaching was one of the most important aspects of their progress and that it enabled them to develop their talent and progress to the level they had achieved thus far. after u19, specialist coaches to develop specific aspects of a player’s game were considered important. most participants agreed that for many ba players a lack of quality, committed coaches with adequate training and remuneration, particularly in the ba communities, were significant limitations to a player’s progression through the system. this is particularly true for batsmen, who require specific technical coaching. i think we were also fortunate enough that the coaches that we had were really committed to the program, really wanted to make a difference in the kids. (participant 8) […] there is not much coaching happening in township schools in any case. (participant 1) support networks the majority of participants identified the importance of emotional support from a parent and/or significant individual from the cricket environment who assisted them to progress during their school cricket phase. however, the players indicated that this is not always true for many young ba players and together with significant financial, logistical and social pressures this compounds their difficulty in progressing in cricket. mentorship was seen as critical to successful progression in cricket to provide guidance, direction, nurturing and an understanding of the requirements of a top-level cricketer. along with individual 20 sajsm vol. 28 no. 1 2016 original research mentoring, ongoing life skills training and a focus on developing the ‘whole’ person, could potentially bridge the gap that ba players experience from the lack of a good education system. a number of respondents felt that suitably trained, experienced, empathetic and committed retired ba players would be best equipped to provide this support. my mother and father have always been there to give advice, not necessarily on field issues, but hard to deal with things off the field. (participant 21) so i think, again, that mentoring program becomes critical. (participant 8) previous research supports the findings of this study of the importance of a variety of support networks in the development of elite sportspersons[9] and facilitating the transitional challenges faced at different stages of their athletic careers.[10] the transition period between junior and senior level is particularly difficult for many sporting communities around the world.[10] the lack of adequate support networks compounds this problem for ba players in the south african context and appropriate programmes provided by the cricketing community could assist in further developing these players. barriers all the current players (n = 11) and the former players (n = 4) made their senior debut at either amateur/provincial or franchise level between the ages of 17and 21 years old. however, only a few made significant progress and consistent selection for franchise and/or national teams. they identified the following barriers as limiting their progress. team environment most of the participants said that it was difficult for ba players to feel comfortable in the current team environments, particularly at senior level. they felt this was due to south africa’s history, differing cultures and languages, outdated mindsets, feeling misunderstood, stereotyping, poor communications, biased selections and a lack of belief and trust in ba players to perform and win games. this group of players felt that this was one of the major reasons that, having progressed to the professional level, they were unable to consistently play and deliver performances necessary to compete for places at a higher level. the vast majority of interviewees believed that there is a need to adapt mindsets and attitudes to assist in the assimilation of different cultures into the senior teams, and to provide an environment in which all players can have a sense of belonging and support to enable them to perform to their potential. so you buy into the talk of the team without actually owning that kind of feeling or really be feeling it. (participant 13) […] you don’t feel welcome and you don’t feel comfortable. (participant 15) for example, team cohesion and culture have been linked to the sporting success of both the individual and team in professional rugby.[11] taylor and bruner[12] found a negative relationship between psychological need satisfaction and social exclusion in elite youth soccer players of blackand white-english ethnic origin. a team environment in which all players can feel comfortable to express themselves both on and off the field, and believing that they have the support of the team leadership, can only enhance both individual and team performance. quality opportunities to compete study participants felt there was a lack of quality opportunities to compete and insufficient playing time at senior level, which had an adverse effect on performance. ba players were often selected, but did not bat in the correct position or bowl sufficient overs. there was also the perception that they needed to outperform their white counterparts to retain their place in the team. many of the players felt that they were currently experiencing a lack of quality opportunity to compete. this perception was supported by the quantitative findings of van  zyl,[5] and csa have taken steps to ensure that coaches at provincial and franchise level select more ba players and play them in their appropriate roles. a number of respondents commented that there is a perception that it is not possible to win matches with ba players in the team. at franchise and national level, winning is the priority and therefore it was felt that this is why ba players, particularly batsmen, were not selected or played in appropriate positions. they were really good, but they just didn’t get the opportunity and they gave up. (participant 6) because of the kind of inbuilt prejudice and mentalities we’ve spoken about people just simply always find excuses not to pick players and it still happens in franchise cricket today. (participant 13) made a 50 on debut and then sort of told to go back and work hard […]. (participant 16) people have looked at them and said, ok, they can only bowl, they can’t bat because batting tends to be associated with thinking, which i think to a larger degree, it’s a deeper systemic thing that ok, black people, black cricketers wouldn’t be able to think on their feet. (participant 6) socio-economic factors all participants identified socio-economic pressures as a significant barrier to progression in cricket for the majority of ba players. while they were personally less affected by these issues, they identified gangsterism, alcohol and drug abuse, hiv/aids, poor nutrition, the dysfunctional education system, singleor no-parent homes and differing family priorities as barriers to success for many ba players. they indicated that lack of finances meant that many players became responsible for family members after leaving school. accessibility to training grounds was limited by transport constraints, distances, time and money. some participants also mentioned that changing social recreation patterns, such as social media, amongst the youth and competition from other sports, particularly soccer and, to a lesser extent, rugby, also pose a threat to growing the game in ba areas. they don’t have the luxury of going even, getting a good education for the first 3 or 4 years because they haven’t got that luxury, so they have to literally go back and go back home and get a minimum paying job and look after their families. it’s a difficult one but it obviously has a lot to do with social and poverty. (participant 19) do you understand this guy has got to get on two trains and three taxis and then he has to walk the last three kilometres to get here? (participant 4) socio-economic factors have been acknowledged as playing a significant role in cricket participation around the world and an australian study found that financial factors may be a barrier to participation in junior sport.[13] while this should not detract from wanting to develop the game in all communities around south africa, it does add an extra layer to the complex issue of socioeconomic barriers faced by ba cricketers. many of the sociosajsm vol. 28 no. 1 2016 21 original research economic factors mentioned are beyond the sphere of influence of the cricket administration, yet there are a number of initiatives that have and still could be implemented to increase and support cricket in ba communities. the current creation of ‘hubs’ and regional performance centres in the ba communities, where talented players from different schools can form well coached composite teams, with access to facilities, equipment and support structures, to compete against one another and ‘traditional cricket schools’, may begin to address some of the socio-economic inequalities. cricket player development pathway by having exposure to a strong development programme and school system, this cohort of ba players were able to access the csa player development pipeline. however, this is unavailable to many ba players. many respondents expressed concern about the perceived decrease in the number of ba players entering the game at a young age, the difficulty in transitioning from u19 to senior level and the decline in participation and standard of club cricket. these factors were perceived to limit opportunities to progress or access the csa pipeline and thus decreased representation at the senior level. having reached the senior level, some interviewees mentioned that ba players were treated differently from white players in terms of lower remuneration offered during contractual negotiations and a lack of investment in ba players, as senior coaches focused only on winning and not on player development. in addition, other participants said that the structure of the game at the amateur level also created barriers for ba players to progress, preventing work and study opportunities, as well as having only six professional franchises. […] as soon as they are out of the school structure they just disappear and you ask yourself where are they […]? (participant 5) but i just see our club system being very […] i think it’s gone backwards. (participant 9) stambulova et al.[10] stated that the transition from junior to senior level is crucial for all athletes who want to reach the elite level in sport. the data presented by van zyl[5] confirmed that all ethnic groups will face challenges at this stage but that these challenges appear to be greater for ba players as highlighted by their lower conversion rate to the franchise and national levels (table 1). therefore strategies are needed to facilitate the specific needs of ba players during this period. csa is introducing community-based competitions to enhance the strength of club cricket. in addition, they are partnering with tertiary institutions and creating provincial academies to address the holistic development of identified players who can develop in a well-structured and supportive environment without having to deal with the socio-economic and cultural pressures on a daily basis. the efficacy of these interventions still needs to be assessed. i think csa should look at building what they built in fort hare […] and what they have done there is then also put an education to it. i think that is a fantastic model for other people to follow. (participant 12) leadership a number of the participants felt that there was a need to encourage committed and accountable behaviours from coaches and leaders throughout the cricketing structures to enable implementation of sustainable development strategies, agreed performance standards and mindset changes at all levels. i strongly believe up until we have the right people in the right positions, especially powerful positions, i think this whole thing will change and will start breeding more black african cricketers, just naturally without having to stress about x,y and z. have the right structures in place, at club level, at school level, everywhere. (participant 8) additional factors intrapersonal attributes participants highlighted the following personal attributes that they believed contributed to cricketing success; self-belief, work ethic, mental toughness, discipline and an inner drive. many of these have been identified in olympic athletes that have achieved success,[9] australian international cricket fast bowlers[14] and elite australian batsmen.[15] […] i sort of let other factors influence me outside of cricket that actually didn’t help me to perform to what i actually could have. […] the fact of feeling inferior, the fact of not feeling good enough that had an effect on actually my performance well does not reflect what potentially i could actually do. (participant 22) with blacks i don’t want to lie to you, these guys have got talent. black cricketers you know they are one of the best people that i have ever come across in terms of skills, but the only problem is its up here, it is how the guys think. i think that is where the gap is in terms of here. (participant 5) targets all study participants commented on targets. some believed they had a positive effect and others felt they had a negative effect on players progressing to the professional level. there was no consensus as to whether targets should be in place at the u19 to franchise level. the majority of respondents felt that targets should be in place at the junior levels but not at national level. it was felt by the interviewees that targets may provide opportunities to ba players that may otherwise not be given them, but there was concern for the psychological effects as a result of labelling and lack of quality from being fast-tracked. quotas is enabling administrators to avoid doing proper development. it’s a number game. (participant 10) i think those targets are put there to try and help coaches make decisions which they normally don’t, so sometimes it is a good thing to have those things there. how it affects the cricketer knowing that he is now a person when they talk like that, that is another debate. (participant 17) quotas and targets have been a part of the south african sports transformation discussion for many years and south african cricket introduced a target of four black (ba, c and i) players at franchise and national level in 1998. this was removed in 2007.[3] this target has resulted in increased coloured (c) representation at franchise and national level but not ba (table 1). it is important that interventions do not simply address demographic representation. while targets for ba cricketers increase the opportunities, they fail to address issues such as team environment and the quality of opportunity to compete, which could adversely affect performance. limitations and further research one of the limitations of this study was that ba players who had not made it to the senior level were not interviewed due to difficulties in logistically identifying and contacting them. the successful players interviewed provided their perception of challenges faced by all ba players, but there may have been other barriers faced by the unsuccessful players. furthermore, the definition used for success may have been too broad, but did allow for a consistent, less subjective 22 sajsm vol. 28 no. 1 2016 original research classification of success. the players ranged from having played one match at franchise level to having represented the national team. batting and bowling statistics may have provided more objective and narrow measures of success. further research is required to determine which of the themes identified are generic to all cricketers in south africa and which are unique to ba players. the implementation of csa initiatives aimed at developing more ba players to perform should be monitored to determine their success. the role of intrapersonal attributes in cricketing success should also be investigated. conclusion this study highlighted a number of barriers and enablers to success in cricket as recalled by ba cricketers. while a number of these barriers may be generic across all ethnic groups in south africa or even internationally, there are a number of factors which may be specific to the ba context. a recent study found similar structural barriers (socio-economic and cultural, overt racism, physical and cultural stereotypes and oppositions and organisational provision and institutional discrimination), to increased representation of ethnic minorities in european football.[16] while it is acknowledged that increasing the ba representation at senior levels is a complex and multi-factorial issue, which includes macroand microecological factors; some of the factors identified in this study could provide insight to addressing some of the challenges identified by this study cohort. increased exposure to the game will create opportunities to identify players for future development within an optimal environment; consisting of good education, equipment, facilities and coaching; by implementing a comprehensive bursary programme in the short term and simultaneously creating opportunities in the ba communities for long term sustainability. enhanced support networks at all levels may better prepare ba players to compete at the elite level. at the senior level, addressing the social climate of teams, and improving the quality of opportunities to compete may enhance the performance of ba players and lower dropout rates providing a bigger pool for selection at franchise and national level. the successful and holistic transformation of south african cricket to ensure long-term sustainability at all levels of the game will require committed leadership by all stakeholders. this will require implementation of integrated changes and adaptation of mindsets to accommodate a diversity of cultures; and in so doing provide developmental opportunities for all talented players to achieve their potential at the professional level. acknowledgements: the authors thank the participants for their time and cooperation in conducting this research and csa for the funding. references 1. sport and recreation south africa (srsa). pilot evaluation. rugby, cricket, athletics, netball, football. a transformation status report. 2013. [http://www.srsa. gov.za/medialib/home/documentlibrary/srsa] accessed august 4, 2014. 2. odendaal a. the story of an african game. new africa books. 2003. 3. csa introduce quota for black african players. [http://www.espncricinfo.com/ southafrica/content/story/679057.html] accessed october 14, 2013. 4. taliep ms, gamieldien r, west sj. an analysis of the performance of black african junior provincial cricket batsmen south african journal of sports medicine 2011;23(3):90-94. 5. van zyl c. a strategy to increase the pool of black african cricket players within the csa pipeline to represent south africa internationally. final project: sports management course 2012/13. world academy of sport. royal halloway, university of london. 6. tucker r, collins m. what makes champions? a review of the relative contribution of genes and training to sporting success. br j sports med 2012;46(8):555-561. [http://dx.doi.org/10.1136/bjsports-2011-090548] 7. henriksen k. the ecology of talent development in sport. phd dissertation. university of southern denmark. 2010. 8. hsieh h-f, shannon se. three approaches to qualitative content analysis. qualitative health research. qual health res 2005;15(9):1277-1288. [http://dx.doi. org/10.1177/1049732305276687] 9. gould d, dieffenbach k, moffett a. the development of psychological talent in u.s. olympic champions. final grant report. december 2001. 10. stambulova n, alfermann d, stauer t, et al. issp position stand: career development and transitions of athletes. ijsep 2009;7(4):395-412. [http://dx.doi.org/10.1080/1612 197x.2009.9671916] 11. hodge k, henry g, smith w. a case study of excellence in elite sport: motivational climate in a world champion team. the sport psychologist 2014;28:60-74. [http:// dx.doi.org/10.1123/tsp.2013-0037] 12. taylor im, bruner mw. the social environment and developmental experiences in elite youth soccer. psychology of sport and exercise 2012;13(4):390-396. [http:// dx.doi.org/10.1016/j.psychsport.2012.01.008] 13. kirk d, carlson t, o’connor a, et al. the economic impact on families of children’s participation in junior sport. aust j sci med sport 1997;29(2):27-33. 14. phillips e, davids k, renshaw i, et al. acquisition of expertise in cricket fast bowling: perceptions of expert players and coaches. j sci med sport 2013;17(1):85-90. [http:// dx.doi.org/10.1016/j.jsams.2013.03.005] 15. weissensteiner jr, abernethy b, farrow d, et al. distinguishing psychological characteristics of expert cricket batsmen. j sci med sport 2012;15(1):74-79. [http:// dx.doi.org/10.1016/j.jsams.2011.07.003] 16. bradbury s, amara m, garcia b, et al. representation and structural discrimination in football in europe. the case of minorities and women. loughborough: loughborough university, 2011. http://www.srsa.gov.za/medialib/home/documentlibrary/srsa http://www.srsa.gov.za/medialib/home/documentlibrary/srsa http://www.espncricinfo.com/southafrica/%20content/story/679057.html http://www.espncricinfo.com/southafrica/%20content/story/679057.html http://dx.doi.org/10.1136/bjsports-2011-090548 http://dx.doi.org/10.1177/1049732305276687 http://dx.doi.org/10.1177/1049732305276687 http://dx.doi.org/10.1080/1612197x.2009.9671916 http://dx.doi.org/10.1080/1612197x.2009.9671916 http://dx.doi.org/10.1123/tsp.2013-0037 http://dx.doi.org/10.1123/tsp.2013-0037 http://dx.doi.org/10.1016/j.psychsport.2012.01.008 http://dx.doi.org/10.1016/j.psychsport.2012.01.008 http://dx.doi.org/10.1016/j.jsams.2013.03.005 http://dx.doi.org/10.1016/j.jsams.2013.03.005 http://dx.doi.org/10.1016/j.jsams.2011.07.003 http://dx.doi.org/10.1016/j.jsams.2011.07.003 case report 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license the great pretender: multi-system tuberculosis and pathological fracture masquerading as a severe acute football groin injury ‒ case study with a 5-year follow-up m lichaba,1,2 mbchb, mphil; w diesel,1 phd; d constantinou,1,2 mbbch, mphil 1 department of exercise science and sports medicine (dessm), school of therapeutic sciences, faculty of health sciences, university of witwatersrand, south africa 2 international federation of sports medicine collaborating centre of sports medicine, johannesburg, south africa corresponding author: m lichaba (mamosilo.lichaba@wits.ac.za) groin injuries account for 2 5% of all sports injuries and up to 8% among footballers.[1]. ice hockey and football present the highest risk for groin injuries, (10 11% of all injuries in these sports are groin injuries). men seem more susceptible to groin injuries than women. the differential diagnosis for groin pain includes intra-abdominal pathology, genitourinary abnormalities, referred pain from the lumbosacral spine and hip pathology.[2] the coexistence of two or more of these conditions is frequent, with unclear diagnosis in 30% of cases. [2] in cases of hip pathology, acetabular fractures are an extremely rare aetiology, especially amongst footballers. acetabular fractures usually happen in highvelocity impact, associated dislocation, adolescent players, and/or osteoporotic/osteopenic bone [3]. rankin, bleakly and cullen[4] in a 6-year review reported hip pathology to be the leading cause of groin pain in the sporting population. however, in the list of hip pathology, labral tears feature at 33%, (second to femoral-acetabular impingement), and no mention at all of acetabular fractures. though acetabular fractures are rare in soccer, the hip is among the joints that tuberculosis (tb) commonly affects. there are reports and warnings of non-sports injuries presenting as sports injuries, including sacroiliac tb, oncological conditions, and rheumatological conditions. tuberculosis (tb) is a very old infectious disease with anthropological evidence of the mycobacterium seen since the 9th millennium. it is still a significant disease, being among the top 10 causes of death worldwide,[5] and remains the leading cause of death in the world from a single infectious disease, ranking higher than hiv/aids.[5] tb’s highest disease burden is in adult men ( 20 – 39 years of age), accounting for more than half the cases.[5] tuberculosis had been declining in the last century, but there has been an increase in recent times due to the advent of the hiv pandemic, the destruction of socio-cultural support systems resulting from urbanization, and worsening conditions of our public health systems and programs. tuberculosis is the most common illness among people living with hiv, who are 16 – 27 times more likely to acquire tb.[5] it is also the leading cause of death amongst these people, accounting for a third of all hiv-related deaths. africa ranks second in the world, with 24% of the total global tb cases.[5] sub-saharan africa has the highest number of people living with hiv/aids, with south africa being amongst the top 10 countries in the world. kwan and ernst[6] refer to hiv and tb as the ‘deadly human syndemic”. they found in their review that the likelihood of getting extrapulmonary tuberculosis (eptb) increases with immune compromise, particularly when cd4 counts fall below 350 cells/mm3. they quote the bone and gut as the highest sites affected by eptb. tb is often difficult to diagnose in patients with very low cd4 counts as the body’s immune response is compromised and traditional pathology tests sometimes fail to detect tb. eptb is even harder to diagnose as it commonly presents with symptoms and signs related to the affected organs and systems, which then mimic afflictions typically affecting such organs and systems. tb is generally a more insidious lowgrade infection, even more so in eptb, especially when infected individuals have a compromised immune system. hence, the diagnosis of eptb may require more extensive and invasive investigations we present the first known reported case of eptb presenting as a football groin injury. in this clinical case, a man presented with a groin injury on his dominant side, which he apparently sustained in football (soccer) practice on the previous day. the man was unable to walk unassisted and had to be transported in a wheelchair. the consulting practitioner grew suspicious upon finding minimal clinical evidence and nothing notable on the x-ray to suggest a severe acute injury. a subsequent detailed workup revealed extrapulmonary tuberculosis (eptb) of the musculoskeletal (msk) and genitourinary tract (gut) systems, complicated by a pathological fracture of the acetabulum, as the cause of the groin injury. management of the eptb resolved the condition with no relapse nor long-term sequelae beyond five years, despite being immunocompromised. we present the clinical case and a five year follow-up. the case serves as a reminder of the possibility that other conditions may mimic sports injuries and further illustrates a rare presentation of such a condition. keywords: extrapulmonary tuberculosis, hiv, aids, acetabular fracture s afr j sports med 2023; 35:1-4. doi: 10.17159/2078-516x/2023/v35i1a13980 mailto:mamosilo.lichaba@wits.ac.za http://dx.doi.org/10.17159/2078-516x/2023/v35i1a13980 https://orcid.org/0009-0001-0467-8658 https://orcid.org/0000-0002-3363-7695 case report sajsm vol.35 no.1 2023 2 case report a 40-year-old male consulted his sports physician one day after sustaining a right groin injury when he slipped and fell into a split position while playing football. the patient was immediately not able to be ambulated due to the severe groin pain. he required assistance and was transported in a wheelchair. the patient did not recall hearing a ‘snap’ or a ‘click’ at the time of injury. he also did not collide with anyone. on examination, the patient was in severe distress due to pain. he was of average athletic build with no signs of cachexia or muscle atrophy. he was apyrexial, not anaemic, not clubbed and pink. the peripheral pulses were all normal. there were no skin changes or deformities observed. no shotty nor matted lymph nodes were palpable on examination, either generally or in the inguinal area. the right groin area was extremely tender to palpation in the area of the anterior hip joint, but no masses nor defects were palpable. there was no “real” leg length discrepancy. he was extremely tense on examination of the right leg, so the reflexes were hard to assess. sensation was normal. the patient was very reluctant to actively move the right hip at all. the log roll test reproduced the patient’s groin pain, worse on internal rotation, but it did not produce any sound. the thomas’ test was limited to 30 degrees of hip flexion, while the faber test reproduced the groin pain and significantly limited external rotation but no sacro-iliac joint (sij) discomfort. the fadir caused groin tenderness on internal rotation. the compression test also reproduced severe groin pain. the straight leg raise test was negative. the knee joint examination was unremarkable. general systemic examination did not reveal any abnormalities other than a small (<1cm diameter) ganglion on the dorsum of the left wrist. he also complained of a recent painless left scrotal swelling, confirmed clinically as a soft but firm mass. the patient’s past medical history confirmed he was hiv positive on antiretroviral therapy (arvs), and revealed poorly controlled hypertension with stage 3 chronic renal failure (crf), (table 1). monitoring done six months before the injury had shown a cd4 count of 276 cells/mm3 and an undetected viral load (vl) of less than 40 cps/ml. on presentation, the cd4 count had fallen to 137, with an undetectable vl (table 1). special investigations ultrasound imaging of the affected groin revealed no significant injury to the soft tissues or muscles (figure 1a). plain x-rays of the right hip (figure 1b) revealed dystrophic calcification in the right pelvis and a lucency through the acetabulum. x-ray of the lumbar spine showed disc space narrowing with disc degeneration across l2/l3 (figures 1c and d). a ct scan of the abdomen and pelvis (figure 2) delayed due to financial constraints and performed a month later, revealed osteolytic lesions of l2/l3 (figures 2a – d) and the right acetabulum, (figures 2a and b) with pathological fractures and associated calcification of the right acetabulum (figures 2a and b). an ultrasound of the scrotum (figure 3) showed a left acute epididymal-orchitis with an associated large left hydrocele and varicoceles. case management the patient was managed with nonsteroidal antiinflammatories whilst being investigated. a month after the initial consultation, the patient returned complaining that the wrist ganglion became significantly bigger (>2cm diameter) and requested it be removed. during the gangliectomy the surgeon observed rice bodies. histology and synovium culture confirmed mycobacterium tuberculosis. a hydrocoelectomy was performed with the urologist finding solid caseous material typical of tb necrosis, in the left epididymis, with tb confirmed histologically. the definitive diagnosis of tb msk and gut was then made in support of multi-organ eptb which included the spine and the hip, consistent with the radiological features. table 1. summary of clinical and pathology results clinical pathology parameter 6 months before injury at time of presentation 6 months post treatment 9 months post treatment* on resumption of treatment at completion of treatment 28 months later admission for coma 8 months post-coma 5 year final follow up bp (mmhg) 160/100 ˠ 170/100 ˠ 130/100 ˠ nm nm 160/110 ˠ 140/85 165/100 ˠ 177/104 crp (mg/l) na 86.1 ˠ nm 10.5 23.6 ˠ 9.3 181.2 ˠ nm 7.6 esr (mm/h) na 74 ˠ nm 44 ˠ 35 ˠ 21 ˠ nm nm 9.0 egfr (ml/min/1.73m2) 47 ˠ 36 ˠ 48 ˠ 40 ˠ nm 31 ˠ 4 ˠ 4 ˠ 3 ˠ vl (cps/ml) < 40 < 40 < 40 nm nm < 40 < 40 < 40 20 cd4 cell count (cells/mm3) 276 ˠ 137 ˠ 332 ˠ nm nm 330 ˠ 380 ˠ 458 ˠ 380 ˠ * indicates tb treatment erroneously stopped. ˠ indicates data out of reference range. bp, blood pressure; crp, c-reactive protein; esr, erythrocyte sedimentation rate; egfr, estimated glomerular filtration rate; vl, hiv viral load; cd4, cd4 lymphocyte count; na, not applicable, nm, not measured. case report 3 sajsm vol. 35 no.1 2023 the patient was referred to the local municipal clinic for anti-tb therapy. at 9 months, the clinic sister erroneously stopped his treatment and on realising this the doctor recommenced the treatment and concluded the recommended 12 months course for eptb. he continued with his arv and antihypertensive treatment. the orthopaedic complications responded well to conservative treatment with analgesia and physiotherapy, requiring no surgery. outcome/follow up at 12 months posttreatment initiation, the patient had recovered fully and was deemed cured of tb. all the orthopaedic complications, including the acetabular fracture, had healed clinically. no control radiology was deemed necessary the inflammatory markers crp and esr also normalised. the cd4 count improved from 137 to 330 cells/mm3 (table 1). unfortunately, the blood pressure control remained poor, and the renal function deteriorated warranting dialysis (table 1). he survived a coma secondary to hypertensive encephalopathy and pulmonary oedema 3 years after his groin pain presentation. at 5 years follow-up, his vl remained undetected, the cd4 count had risen above 350/cmm3 and the inflammatory markers were below 10 units (table 1). he returned to work full-time with no clinical sequelae of the multisystem tb or encephalopathy. he continued haemodialysis three times a week for crf. he did not resume playing football or engaging in any physical activity due to his fear of injury. he began to consider himself an "invalid" because of the frequent need for dialysis. he was advised to engage in a chronic disease rehabilitation program appropriate for his clinical and metabolic status, which he unfortunately never took up. main points to consider though hip pathology is a common cause of groin pain, acetabular fractures feature least in the list of hip aetiologies for sports-related groin disruptions. acetabular fractures are typically caused by high-velocity trauma or low bone strength. although acetabular fractures are very rare in soccer, there are well-documented cases in the literature of them occurring during recreational games even at low velocity with no contact. most of these injuries happen with the position of risk being hip flexion in internal rotation, resulting in posterior fracture-dislocations, with total functional failure acutely [5]. in our case, the tb probably caused osteolysis of the bone thus making the acetabulum vulnerable to break from a relatively low velocity, indirect injury. fig. 1. (a) x-ray of the pelvis ap view; (b) x-ray of the right hip ap view; (c) lumbar spine x-ray, ap view; (d) lumbar spine x-ray lateral view fig. 2. ct scan lumbar spine and pelvis ap and lateral views case report sajsm vol.35 no.1 2023 4 tuberculosis and hiv are highly prevalent in south africa, which means that practitioners in any speciality must be vigilant for hiv and tb-related complications, even in young and active individuals. our patient fits the profile of being at high risk for such complications, given his demographic and geographic profile. while it is important to consider sporting participation in active young individuals, a high index of suspicion should be maintained if the clinical picture does not fit the expected presentation, if the symptoms are exaggerated, or if there is an unsatisfactory response to conventional treatment. moreover, this patient would have likely benefited from continuing to participate in sports. unfortunately, he did not pursue it due to fear of reinjury, medical complications, and loss of physical prowess. conclusion this case reminds us of the insidious, atypical nature of the presentation of tb, especially in immunocompromised individuals. it also highlights how immunocompromising systemic or local afflictions may predispose to otherwise very rare conditions such as acetabular fractures, causing major tissue damage and disability from relatively low-velocity force. sports physicians should be cognisant of the role of infections in the aetiology of health disruptions of athletes, especially in the african (sub – saharan) context. the focus on aetiology should not be limited to trauma alone. a broadminded, holistic approach to athletes' challenges, even if presenting as musculoskeletal disturbances, is critical. a comprehensive systemic review of presenting symptoms, signs, and general medical history is mandatory. acetabular fractures though rare in sports cause total dysfunction and can result in severe long-term sequelae and should not be missed. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the author would like to acknowledge and thank the patient and his family for allowing us the privilege to use his most sensitive clinical information; the specialists who assisted in the clinical and surgical management of the patient; and the encouragement of seniors at wits university. author contributions: ml collected data and drafted the case. dc revised the case. dc, wd and ml finalised the writing of the manuscript. references 1. ekstrand j, hiding j. the incidence and differential diagnosis of acute groin injuries in male soccer players. scand j med sci sports 2007; 9(2): 98-103. [doi:10.1111/j.16000838.1999.tb00216.x] 2. morelli v, smith v. groin injuries in athletes. am fam physician 2001;64:1405 – 1414 [pmid: 11681783.] 3. giza e, mithöfer k, matthews h, vrahas m. hip fracturedislocation in football: a report of two cases and review of the literature. br j sports med 2004 aug;38(4):e17. [doi: 10.1136/bjsm.2003.005736] [pmid: 15273210; pmcid: pmc1724879] 4. rankin at, bleakley cm, cullen m. hip joint pathology as a leading cause of groin pain in the sporting population: a 6-year review of 894 cases. am j sports med 2015; 43(7):1698-1703. [doi: 10.1177/0363546515582031] 5. world health organization. hiv/aids: fact sheet: world health organization [updated 15 november 2019]. available from: https://www.who.int/news-room/fact-sheets/detail/hivaids (accessed 19 december 2019). 6. kwan ck, ernst jd. hiv and tuberculosis: a deadly human syndemic. clin microbiol rev 2011 apr;24(2):351-376. [doi: 10.1128/cmr.00042-10] [pmid: 21482729; pmcid: pmc3122491] fig. 3. ultrasound of the left scrotum https://doi.org/10.1111/j.1600-0838.1999.tb00216.x https://doi.org/10.1111/j.1600-0838.1999.tb00216.x https://doi.org/10.1177/0363546515582031 https://www.who.int/news-room/fact-sheets/detail/hiv-aids https://www.who.int/news-room/fact-sheets/detail/hiv-aids jsm0404pg000ed. sports medicine vol 16 no.1 2004 29 introduction in 1982 the department of pharmacology at the university of the free state was approached by several sports administrators to analyse urine samples from competitors for the presence of prohibited substances. an increasing number of competitors had seemingly turned to the use of drugs in an effort to enhance performance. analytical procedures were set up for the detection of all chemical substances banned in sport according to the official list of the international olympic committee (ioc),2 which is revised and published annually. in 1983 urine samples collected at 3 different sporting events were tested for a few stimulants.1 since 1984, screening for all banned stimulants and narcotics was performed on all urine specimens collected at sporting events, and from 1986 this included screening for anabolic steroids.3-5 soon thereafter diuretics and β-blockers were added to the array of testing procedures. after thorough testing and inspection by the ioc (subcommission doping and biochemistry in sport), accreditation was granted to the south african doping control laboratory (department of pharmacology, university of the free state) in 1995. the laboratory is therefore authorised to analyse urine samples from international competitors and athletes. annually each ioc-accredited laboratory must supply the ioc with statistics of the samples they have analysed in order to allow the ioc to construct a global picture concerning doping in sport. the aim of this study was to summarise the results of the past 8 years of dope testing at the south african laboratory (from the time ioc accreditation was awarded), and to compare these results with a summary of statistics from the iocaccredited laboratories. method all urine samples received in the laboratory were screened for all the groups of substances on the ioc list. each group has its own unique method of analysis as described below: • stimulants — alkaline extraction of urine with ether and injection of the extract onto a gas chromatograph equipped with a nitrogen-specific detector. • narcotic analgesics — hydrolysis of urine followed by alkaline extraction, derivatisation and gas chromatography with a mass selective detector (gc/msd). • anabolic agents — gc/msd after deconjugation and derivatisation of the urine extracts. • diuretics — methylation of the urine extract followed by gc/msd. original research article drugs in sport — testing results from the south african laboratory 1995 2002 p j van der merwe (phd) south african doping control laboratory, department of pharmacology, university of the free state, bloemfontein abstract objective. to summarise the results of the past 8 years obtained at the south african doping control laboratory and to compare the results with international statistics. method. screening procedures were performed on 14 017 urine samples collected from competitors in 54 different sporting codes during the period 1995 2002. samples were analysed using gas chromatography and gas chromatography/mass spectrometry for the presence of prohibited substances, which are listed by the international olympic committee (ioc). results. the results obtained were compared with those of the ioc-accredited laboratories. prohibited substances were detected in 300 samples (2.14%), of which 45.6% contained anabolic agents and 34.6% stimulants. the positive samples from the ioc laboratories contained 58.7% anabolic agents and 20.8% stimulants. testosterone and nandrolone were the anabolic agents most frequently detected in positive samples, both in south africa and internationally. the ephedrines as a group accounted for most stimulants detected in positive samples. conclusion. it is of concern that the percentage of positive samples (2.14%) obtained in our laboratory is higher than the 1.70% in ioc laboratories. it is therefore necessary that doping control to curb the use of prohibited substances should continue and expand. correspondence: p j van der merwe department of pharmacology university of the free state po box 339 bloemfontein 9300 tel: 051-401 3182 fax: 051-444 1523 e-mail: gnfmpvdm.md@mail.uovs.ac.za • β-blockers — after hydrolysis and derivatisation the urine extract is injected onto a gs/msd (screening for β-blockers is not performed routinely but only for certain events). the screening procedure results are compared with reference standards and the possible presence of a doping agent and/or metabolite is indicated. confirmatory analysis must be performed on positive results to provide unequivocal identification of the drug and/or metabolite.5 during 1995 1997 the decision whether to test athletes within their code rested with the individual sport federations. the latter were responsible for collecting and dispatching samples to the laboratory, and received the results directly. in 1997 the south african institute for drug free sport (saids) was appointed and empowered in terms of act no. 14 of 1997 to be the only body authorised to govern dope testing in south africa. subsequently, saids was responsible for all urine collection and result management, thus divesting the individual sports federations from any responsibility. from 1998 2002 all samples were received from saids. urine samples were collected from provincial, national and international competitors, including competitors from aboard competing in south africa. the identity of the competitors was unknown to the laboratory and it was therefore not possible to distinguish between local and foreign competitors. a few samples were received from namibia, kenya, mauritius and nigeria. results and discussion approximately 1 500 samples were analysed annually except for the years 1999, 2001 and 2002 (table i). in 1999 with the all africa games held in johannesburg, more than 400 samples were analysed over a period of 10 days6 and this accounted for the increase in the number of samples for that year. the saids expanded their testing programme in 2001 and this accounted for the increase in the number of samples for 2001 and 2002. a total of 14 017 samples were analysed over the 8 years. the percentage of positive doping cases each year is also given in table i, fluctuating between 1.49% in 1998 and 3.02% in 1999, with an average of 2.14%. this is higher than the ioc laboratories' average of 1.70% (range 1.61 1.90%). table ii gives the number of different sports in which competitors were tested. the saids systematically increased the number of sports where testing was conducted, totalling 54 altogether. table ii also indicates that in many sports no competitors tested positive for the use of banned substances. urine samples for doping control can be collected from competitors in-competition (immediately before, during or immediately after an event) or out-of-competition (during the training period both during and out of the competitive season). anabolic agents are considered to be training drugs, that is, drugs taken during the off-season training period so that they will not be present in the body during competition. out-of-competition testing, where the sampling officer collects competitors' urine samples at home or at the training place, was instituted to curb the use of anabolic agents. the percentage of samples received from out-of-competition testing locally as well as internationally is given in fig. 1. more than 40% of the total number of samples analysed internationally each year were from out-of-competition testing, while this figure is far lower in south africa. however, there was a large increase in 2002, which is almost equal to the international figure. the percentage of positive samples from local out-of-competition testing is given in table ii. the different groups of substances found in positive samples are given in fig. 2. of the 300 positive samples, almost half (45.4%) contained anabolic agents, while 34.6% contained stimulants and 15% diuretics. narcotics (1.9%), 30 sports medicine vol 16 no.1 2004 table i. number of samples analysed each year and percentage of positive samples year number of samples % positive 1995 1 384 2.82 1996 1 549 1.94 1997 1 324 2.27 1998 1 478 1.49 1999 2 119 3.02 2000 1 451 1.72 2001 2 321 1.68 2002 2 391 2.20 table ii. number of samples number of different sports from out-of-competition involved and percentage of testing and percentage sports with positive doping samples containing banned cases substances number of sports % positives number of samples % positives year 1995 24 37.5 104 1.9 1996 16 62.5 280 0 1997 22 54.5 93 3.2 1998 23 52.2 292 0.7 1999 33 60.2 204 3.9 2000 36 27.2 307 0.3 2001 44 36.4 585 1.5 2002 45 42.2 959 0.7 1995 1996 1997 1998 1999 2000 2001 2002 south africa international p e rc e n ta g e ( % ) 60 50 40 30 20 10 0 fig.1. percentage of samples from out-of-competition testing. β-blockers (1.5%) and ‘others’ (1.6% cannabis and masking agents) were found in only a few samples. the ioc laboratories' statistics differ in that more positive samples contained anabolic agents (58.2%), with less stimulants (20.8%) and diuretics (3.8%). the group ‘others’ positive samples (15%) included mainly cannabis, of which there is a high incidence of use internationally. cannabis use seems to be not such a big problem in south african sport although it is possible that the sports where such abuse may be widespread were not adequately targeted. the main stimulants and anabolic agents identified in positive samples are given in figs 3 and 4, where they are expressed as a percentage of the number of positive samples containing stimulants and anabolic agents, respectively. in south africa as well as internationally the ephedrines (ephedrine, norpseudoephedrine, pseudoephedrine, norephedrine and methylephedrine), which are active ingredients in many medications for flu and coughs and can be bought at pharmacies without a prescription, accounted by far for most of the positive samples containing stimulants. fencamfamine (reactivan) was more frequently detected in south africa than in other countries, while amphetamine, cocaine and caffeine showed up more frequently in other countries. testosterone and nandrolone accounted for the most positive samples containing anabolic agents, both in south africa and internationally. in south africa there is an increasing use of stanozolol. this anabolic agent and methandienone, are not registered products in south africa and can only be obtained on the ‘black market’. in some urine samples 3 or 4 different anabolic agents were identified in the same sample, which shows the extreme to which athletes are prepared to go in an effort to gain advantage from the use of these agents. although there is severe punishment for competitors who violate the rules (up to 2 years ban from any competition for the use of anabolic agents) they are still prepared to take chances and use banned substances in the hope that they will not be caught. there is a similarity in the pattern of stimulants and anabolic agents identified in positive doping cases between south africa and the ioc-accredited laboratories. the results of this study show that there was a decline in the percentage of positive samples since 1990 1991 when more than 5% of the samples tested positive.3 however, the average percentage of positive samples (2.14%) is still higher than the international average of 1.7%. it is still a concern that some of south africa's top competitors are unaware that medication could contain banned substances, as illustrated by the many samples that tested positive for the ephedrines. the question may be asked whether the dope testing programme has the desired effect. by way of illustration, the percentage of positive samples obtained each year for 4 different sports is given in table iii. for sports a, b and c positive samples were recorded each year with no decline. for sport d a high percentage of positive samples was recorded in 1995. no testing was done in the following 3 years, mainly because the federation involved did not do any testing. when testing was resumed by saids in 1999, a high number of positive samples were again obtained. during 2000 2002, more extensive testing was done on the competitors of that sport but no positive samples were identified. this indicates that the institution of regular testing had the desired effect. conclusion it is of concern that there has been no decline in the number of positive samples during the past 8 years. it is therefore necessary to continue to monitor the use of prohibited substances in sport. sports medicine vol 16 no.1 2004 31 stimulants 34.6% steroids 45.4% diuretics 15% a b c d stimulants 20.8% steroids 58.2% others 15% b a c d percentage (%) 0 10 20 30 40 50 60 70 80 ephedrines salbutamol fencamfamine amphetamine cocaine caffeine south africa international 6.4 4.8 1.4 5.3 9.0 0.4 13.8 49.7 70.3 55.3 fig. 3. main stimulants identified in positive samples. metenolone stanozolol methandienone testosterone nandrolone percentage (%) 0 10 20 30 40 50 south africa international 5.3 4.2 11.1 10.7 7.4 9.6 25.9 34.4 38.1 27.5 fig. 4. main anabolic agents identified in positive samples. fig. 2. spread of positive samples among the different groups of substances (a = cannabis and masking agents (rsa 1.6%, ioc 15%); b = β-blockers (rsa 1.5%, ioc 0.7%); c = narcotics (rsa 1.9%, ioc 1.5%); d = diuretics (rsa 15%, ioc 3.8%). 32 sports medicine vol 16 no.1 2004 competitors should realise that there are no short cuts to success. success can only be earned by disciplined hard work and commitment. all credit should be given to saids for their expanded programme of testing in south africa and they need to be fully supported by the south african sporting community. acknowledgement we wish to thank saids for providing finances for the analysis. references 1. hundt hkl, van der merwe pj, van velden dj. drugs in sport: a report of laboratory investigations into the prevalence of their use in south africa. s afr med j 1984; 66: 878-81. 2. international olympic committee. list of prohibited classes of substances and prohibited methods. lausanne: international olympic committee, medical commission, 2001. 3. van der merwe pj. verbode middels in sport: resultate van toetsing vir die tydperk 1986 1994. south african journal sports medicine 1995; 2 (2): 15-18. 4. van der merwe pj, hundt hkl, müller fo, van velden dp. drugs in sport the first 5 years of testing in south africa. s afr med j 1988; 74: 161-2. 5. van der merwe pj, kruger hsl. drugs in sport the results of the past 6 years of dope testing in south africa. s afr med j 1992; 82: 151-3. 6. van der merwe pj, kruger hsl, pieterse jw, pretorius mj, de kock nj. report on the doping control during the 7th all africa games in south africa. south african journal sports medicine 2000; 7(3): 14-16. table iii. percentage of positive samples in certain sports year sport a sport b sport c sport d 1995 1.6 1.4 1.1 16.7 1996 0.4 3.2 0.5 nt 1997 1.1 1.0 2.2 nt 1998 1.1 1.5 0.7 nt 1999 2.0 3.1 0.4 9.9 2000 1.0 1.9 1.5 0.0 2001 1.5 3.1 0.3 0.0 2002 3.4 2.3 0.8 0.0 nt = not tested. 38 sajsm vol 18 no.2 2006 introduction many studies have examined the physical characteristics of elite, 3,9 amateur, 16,19 adolescent 6,18,19 and pre-adolescent rugby players. 17 a majority of these analyses divide players into two distinct categories – forwards and backs, based on unique physiological criteria specific to these positions. 3,6,16, 19 information derived from these studies may be used to identify superior rugby players and also guides conditioning strategies that may enhance team and individual performance. the south african rugby union green squad is a selection of elite junior players who represent the next generation of national team talent. the goal of the green squad programme is to identify and develop rugby talent with a long-term vision of channelling these players into the national squad. as rugby is a highly demanding physical, tactical and skill-based team sport, 9 substantial resources and emphasis should be directed towards developing and maintaining physical fitness in players from an early age. 10 in accordance with this, the objective of the study was to provide a descriptive profile of the under-16 and under-18 year elite junior players. specifically, the aim was to highlight the anthropometric, strength and speed differences between the 9 categories of playing positions and between the 2 age original research article fitness and body composition profiling of elite junior south african rugby players j durandt1 (bsc (med) (hons) exercise science (biokinetics)) s du toit1 (ba (hons) biokinetics) j borresen2 (bsc (med) (hons) exercise science (biokinetics)) t hew-butler2 (dpm) h masimla3 (ba (phys ed)) i jakoet3 (mb chb, msc (sports medicine)) m lambert2 (phd) 1 discovery health high performance centre, sports science institute of south africa, newlands, cape town 2 uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town 3 south african rugby union, newlands, cape town abstract objective. the aim of this study was to describe the body composition, strength and speed characteristics of elite junior south african rugby players. design. cross-sectional. setting. field study. subjects. rugby players (16 and 18 years old, n = 174) selected for the south african rugby union national green squad. outcome measures. body composition, 10 m and 40 m speed, agility, 1rm bench press, underhand pull-ups, push-ups, multistage shuttle run. results. the under-16 players were on average shorter (175.6 ± 5.7 v. 179.2 ± 6.7 cm), weighed less (76.5 ± 8.2 v. 84.8 ± 8.3 kg) had less upper body absolute strength (77.1 ± 11.8 kg v. 95.3 ± 16.7 kg) and muscular endurance (41 ± 12 v. 52 ± 15 push-ups) and aerobic fitness (87.1 ± 19.4 v. 93.5 ± 15.3 shuttles) than the under-18 players. there were no differences in body fat, sprinting speed correspondence: m lambert uct/mrc research unit for exercise science and sports medicine po box 115 newlands 7725 cape town, south africa tel: 021-650 4558 fax: 021-686 7530 e-mail: mlambert@sports.uct.ac.za (10 m and 40 m) or agility between the two age groups. there were differences between playing positions, with the props having the most body fat, strongest upper bodies, slowest sprinting speed, least agility and lowest aerobic capacity compared with players in the other positions. conclusion. this study provides data for elite junior rugby players and can be used to monitor the progression of players after intervention while also assisting with talent identification for the different playing positions. pg38-45.indd 38 6/28/06 1:49:04 pm sajsm vol 18 no.2 2006 39 groups with the intention of using the data for future talent identification and training intervention projects. this study is novel, as no such data exist on junior rugby players. methods rugby players (n = 174) selected for the south african rugby union national green squad in 2003 were used in this study. the players were selected from 14 provincial under-16 teams which competed at the national grant komo tournament and 14 provincial under-18 teams which competed at the annual under-18 national craven week tournament. players were selected from these provincial teams by a national panel appointed by the south african rugby union. the players were divided into 16-year-old (n = 92) and 18-year-old groups (n = 82). the study was cleared by the university of cape town research and ethics committee. players gave their consent to participate and an informed consent form was signed by the parent/guardian of each player. the testing was supervised by the first author at all venues. wherever possible all tests were completed on the same day in the same order as described below: 1. body composition 2. 10 m and 40 m speed 3. illinois agility test 4. 1rm bench press 5. underhand pull ups 6. push-ups 7. multistage shuttle run. for various reasons beyond our control, some of the subjects did not complete all the tests. this is reflected in the sample size when the data are displayed. 1. body composition body mass was recorded on a calibrated scale (seca model 708, hamburg, germany) and recorded to the nearest 0.1 kg. the players were weighed in underpants and without shoes. the stature of each player was recorded to the nearest millimetre, using a stadiometer (seca model 708, hamburg, germany). the triceps, biceps, subscapular, supra-iliac, calf, thigh and abdominal skinfold thicknesses were measured according to the procedures described by ross and marfell-jones. 20 body fat was estimated as the sum of 7 skinfolds (mm) and as a percentage of body mass. 8 2. 10 m and 40 m speed the warm-up before this test consisted of a minimum of 10 minutes of submaximal running, followed by an appropriate stretching regimen and some acceleration sprints to familiarise the player with the pacing. an electronic sprint timer with photo-electric sensors was set at a height of 1.25 m and placed at 10 m and 40 m intervals from the start line. the player was instructed to crouch in the start position, 30 cm from the start line, after which he sprinted maximally for 40 m through the sensors. the player completed two maximal effort runs separated by a 5 10 minute recovery period. if the player was tested on a grass surface boots were worn, but no starting blocks were allowed. when testing occurred indoors, running shoes without spikes were used. the fastest 10 m and 40 m times for each player were recorded. 3. illinois agility test this test, modified from getchell, 14 measured the player’s ability to accelerate, decelerate and change direction. the test started with the player lying in the prone position on the starting line with his chin touching the floor. on the signal of the whistle the player stood up and accelerated towards and around the cones, set up as prescribed for this test. 14 the time taken to complete the course through the cones was recorded. the player had two attempts with a minimum rest period of 4 minutes between tests. the fastest time was recorded. 4. 1rm bench press the player lay supine on a bench with his feet flat on the floor and his hips and shoulders in contact with the bench. an olympic bar was gripped 5 10 cm wider than shoulder width, using a closed pronated grip. the player started this test by lowering the bar in a controlled manner to the centre of the chest, touching the chest lightly and then extending upwards until the arms were in a fully locked position. a light warm-up set of 10 repetitions was performed using a 20 kg weight. this was followed by 6 8 repetitions at approximately 30 40% of the estimated 1rm, which was based on the player’s previous resistance training experience. a 2-minute stretching routine for the shoulders and chest was completed, followed by a further 6 repetitions on the bench press at a weight corresponding to 60% of the estimated 1rm. the player then rested for 3 4 minutes before attempting his 1rm. if the 1rm was successful, the player had a 5-minute rest before attempting a bench press using a resistance that had been increased by 2.5% to 5.0%. conversely, the resistance was decreased by 2.5% to 5.0% if the lift was not successful. the test was scored as the maximum weight (kg) that could be lifted with one repetition. a lift was disqualified if the player raised his buttocks off the bench during the movement, bounced the bar off the chest, extended the arms unevenly, or if the spotter aided the lift. 1rm absolute bench press was recorded in kilograms (kg), and the 1rm relative bench press was calculated as 1rm/ (bodyweight 0.57 ). 7 5. underhand pull-ups the player started the test from a hanging position (arms fully extended) with the hands placed 10 cm apart in an underhand (supinated) grip. a valid pull-up required that the player’s chin reached above the bar, and that at the end of each descent his arms were fully extended and his body remained stationary. the player continued the test until he could no longer lift himself to the bar. the test was scored as the number of valid pull-ups completed. pg38-45.indd 39 6/28/06 1:49:04 pm 40 sajsm vol 18 no.2 2006 6. push-ups the player began in a prone position with his hands on the floor, thumbs shoulder-width apart and elbows fully extended. keeping the back and body straight the player descended to the tester’s fist, placed on the floor below the player’s sternum, and then ascended until the elbows were fully extended. if the player did not adhere to these specifications the repetition was not counted. the test was scored as the number of push-ups performed in 1 minute. 7. multistage shuttle run this progressive multistage shuttle run was based on the protocol of lèger et al. 15 a 20 m distance was measured out and marked on the floor. the players ran between these 2 lines. players were instructed to complete each 20 m distance (lap) and turn according to the pace determined by the recorded sound signal. one foot of each player was required to touch the marked line, coinciding with the sound signal. the timing between signals started slowly and became progressively faster each minute. the players were warned if they failed to complete the 20 m distance in the required time for 2 consecutive laps. if this continued for the next lap they were withdrawn from the test. players were also allowed to voluntarily withdraw from the test if they were unable to maintain the required pace. the score was recorded as the number of the last completed lap. statistics data are reported as means ± standard deviations. a twoway analysis of variance was used to determine differences between age group and playing position for the different variables. when the overall f-value was significant for the main effect 'position', a scheffe’s post-hoc test was used to identify specific differences between positions. statistical significance was accepted when p < 0.05. results there were no interactions between ‘age’ x ‘playing position’ for any of the measurements. the stature of 16-year-old players was significantly less than the 18-year-old players (175.6 ± 5.7 v. 179.2 ± 6.7 cm; p < 0.001). significant stature differences occurred between positions, with locks being taller than all other group positions (table i). sixteen-year-old players weighed significantly less than the 18-year-old players (76.5 ± 8.2 v. 84.9 ± 8.3 kg; p < 0.0001). props were the heaviest and scrumhalves the lightest players in both age groups. differences in body mass between positions are shown in table ii. table i. the stature (cm) of 16-year-old (n = 92) and 18-year-old (n = 82) rugby players* position 16 years n 18 years n prop 177.5 ± 6.0 10 180.3 ± 3.8 13 hooker 173.4 ± 3.1 7 178.8 ± 6.3 5 lock 187.2 ± 5.5 10 194.2 ± 5.2 11 loose forward 180.8 ± 4.3 16 181.3 ± 6.3 15 scrumhalf 165.9 ± 10.3 6 167.8 ± 5.6 8 flyhalf 173.0 ± 5.3 8 177.6 ± 7.6 7 wing 171.7 ± 5.2 15 176.4 ± 8.2 9 centre 173.4 ± 6.5 12 179.1 ± 8.5 11 fullback 178.1 ± 5.5 8 177.6 ± 9.0 3 average 175.6 ± 5.7 92 179.2 ± 6.7 82 appropriate post-hoc analyses position main effects significance props v. scrumhalf p < 0.00002 props v. wings p < 0.05 hookers v. scrumhalf p < 0.015 locks v. all positions p < 0.00004 loose forward v. scrumhalf p < 0.00001 loose forward v. wing p < 0.0007 scrumhalf v. flyhalf p < 0.013 scrumhalf v. centre p < 0.003 scrumhalf v. fullback p < 0.0009 * the f-ratio was 12.56 for group (p < 0.001) and 19.8 for position (p < 0.0001). pg38-45.indd 40 6/28/06 1:49:05 pm sajsm vol 18 no.2 2006 41 table ii. the body mass (kg) of 16-year-old (n = 92) and 18-year-old (n = 82) rugby players* position 16 years n 18 years n prop 95.5 ± 14.1 10 100.8 ± 13.1 13 hooker 79.5 ± 6.4 7 93.1 ± 5.7 5 lock 87.1 ± 8.8 10 95.2 ± 8.4 11 loose forward 80.5 ± 7.3 16 88.2 ± 5.5 15 scrumhalf 60.8 ± 8.9 6 70.3 ± 4.9 8 flyhalf 69.6 ± 5.3 8 75.0 ± 8.2 7 wing 68.4 ± 6.7 15 77.7 ± 12.2 9 centre 71.9 ± 9.1 12 85.1 ± 9.9 11 fullback 75.2 ± 6.8 8 78.8 ± 6.6 3 average 76.5 ± 8.2 92 84.9 ± 8.3 82 appropriate post-hoc analyses position main effects significance prop v. hooker p < 0.00660 prop v. loose forward p < 0.00001 prop v. scrumhalf p < 0.00001 prop v. flyhalf p < 0.00001 prop v. wing p < 0.00001 prop v. centre p < 0.00001 prop v. fullback p < 0.00001 hooker v. scrumhalf p < 0.00001 hooker v. flyhalf p < 0.00889 hooker v. wing p < 0.00715 lock v. scrumhalf p < 0.00001 lock v. flyhalf p < 0.00001 lock v. wing p < 0.00001 lock v. centre p < 0.00006 lock v. fullback p < 0.00180 loose forward v. scrumhalf p < 0.00001 loose forward v. flyhalf p < 0.00521 loose forward v. wing p < 0.00005 centre v. scrumhalf p < 0.00975 * the f-ratio was 33.28 for group (p < 0.0001) and 24.84 for position (p < 0.0001). table iii. sum of 7 skinfold measurements (mm) for 16-year-old (n = 91) and 18-year-old (n = 79) rugby players* position 16 years n 18 years n prop 110.8 ± 37.6 10 119.6 ± 42.8 12 hooker 78.2 ± 17.2 7 80.7 ± 31.9 5 lock 73.6 ± 32.8 10 68.1 ± 18.9 10 loose forward 64.7 ± 19.6 16 62.3 ± 12.3 14 scrumhalf 54.0 ± 18.0 6 58.3 ± 17.1 8 flyhalf 59.3 ± 10.3 8 57.2 ± 13.6 7 wing 54.7 ± 12.1 14 57.5 ± 8.5 9 centre 51.2 ± 10.1 12 63.7 ± 20.5 11 fullback 54.8 ± 15.2 8 55.5 ± 20.1 3 average 66.8 ± 19.2 91 69.2 ± 20.6 79 appropriate post-hoc analyses position main effects significance prop v. all positions p < 0.00204 * the f-ratio was 0.43 for group (p = 0.51) and 15.47 for position (p < 0.0001). table iv. per cent body fat for 16-year-old (n = 91) and 18-year-old (n = 82) rugby players* position 16 years n 18 years n prop 20.0 ± 5.5 10 20.0 ± 4.2 13 hooker 16.4 ± 2.4 7 15.3 ± 3.7 5 lock 14.8 ± 4.6 10 14.2 ± 2.0 11 loose forward 14.2 ± 3.1 16 13.9 ± 1.8 15 scrumhalf 13.2 ± 4.2 6 12.9 ± 2.7 8 flyhalf 13.6 ± 2.0 8 13.3 ± 2.4 7 wing 13.3 ± 2.9 14 13.1 ± 1.6 9 centre 12.0 ± 1.8 12 13.8 ± 2.9 11 fullback 13.0 ± 4.6 8 12.1 ± 3.4 3 average 14.5 ± 3.4 91 14.3 ± 2.7 82 appropriate post-hoc analyses position main effects significance prop v. lock p < 0.00001 prop v. loose forward p < 0.00001 prop v.slcrumhal p < 0.00001 prop v. flyhalf p < 0.00001 prop v. wing p < 0.00001 prop v. centre p < 0.00001 prop v. fullback p < 0.00001 * the f-ratio was 0.15 for group (p = 0.70) and 10.69 for position (p < 0.0001). pg38-45.indd 41 6/28/06 1:49:05 pm 42 sajsm vol 18 no.2 2006 table v. bench press (absolute; kg) results for 16-year-old (n = 71) and 18 year old (n = 80) rugby players* position 16 years n 18 years n prop 97.5 ± 16.9 8 102.7 ± 26.3 13 hooker 83.0 ± 10.4 5 107.0 ± 4.5 5 lock 80.6 ± 12.1 9 95.0 ± 15.8 11 loose forward 82.7 ± 18.4 11 101.4 ± 21.3 14 scrumhalf 63.0 ± 6.7 5 81.9 ± 13.1 8 flyhalf 73.0 ± 9.7 5 82.1 ± 20.8 7 wing 69.6 ± 7.8 13 94.4 ± 23.2 8 centre 72.2 ± 18.4 9 98.2 ± 12.1 11 fullback 72.5 ± 6.1 6 95.0 ± 13.2 3 average 77.1 ± 11.8 71 95.3 ± 16.7 80 appropriate post-hoc analyses position main effects significance prop v. scrumhalf p < 0.00231 prop v. flyhalf p < 0.02941 prop v. wing p < 0.00094 * the f-ratio was 37.59 for the group (p < 0.00001) and 4.00 for position (p < 0.00001). table vi. bench press (relative) results for 16-yearold (n = 71) and 18-year-old (n = 80) rugby players* position 16 years n 18 years n prop 7.39 ± 1.08 8 7.36 ± 1.63 13 hooker 6.99 ± 0.92 5 8.09 ± 0.51 5 lock 6.31 ± 0.81 9 7.09 ± 1.12 11 loose forward 6.77 ± 1.33 11 7.86 ± 1.53 14 scrumhalf 6.16 ± 0.48 5 7.25 ± 1.12 8 flyhalf 6.58 ± 0.70 5 6.98 ± 1.49 7 wing 6.28 ± 0.70 13 7.82 ± 1.52 8 centre 6.35 ± 1.36 9 7.81 ± 0.76 11 fullback 6.27 ± 0.71 6 7.81 ± 0.76 3 average 6.55 ± 1.00 71 7.54 ± 1.30 80 * the f-ratio was 10.83 for group (p < 0.001) and 1.50 for position (p < 0.16). table vii. number of pull-ups performed by 16-yearold (n = 77) and 18-year-old (n = 75) rugby players* position 16 years n 18 years n prop 7 ± 7 9 11 ± 6 13 hooker 9 ± 4 6 13 ± 3 5 lock 7 ± 5 9 8 ± 6 9 loose forward 10 ± 5 12 13 ± 6 13 scrumhalf 12 ± 4 5 16 ± 11 6 flyhalf 12 ± 5 6 10 ± 2 7 wing 11 ± 3 14 13 ± 4 8 centre 13 ± 4 9 13 ± 4 11 fullback 10 ± 3 7 13 ± 3 3 average 10 ± 5 77 11 ± 6 75 appropriate post-hoc analyses position main effects significance prop v. scrumhalf p < 0.009 prop v. wing p < 0.02 prop v. center p < 0.006 lock v. scrumhalf p < 0.03 * the f-ratio was 2.8 for group (p = 0.10) and 3.8 for position (p < 0.001). table viii. number of push-ups performed by 16year-old (n = 84) and 18-year-old (n = 70) rugby players*. position 16 years n 18 years n prop 34 ± 11 10 46 ± 18 13 hooker 44 ± 14 6 61 ± 11 5 lock 41 ± 14 10 46 ± 6 8 loose forward 42 ± 14 13 54 ± 15 13 scrumhalf 44 ± 9 6 53 ± 19 6 flyhalf 50 ± 9 6 56 ± 17 6 wing 38 ± 8 15 50 ± 16 8 centre 43 ± 15 11 56 ± 10 10 fullback 35 ± 7 7 45 ± 0.0 1 average 41 ± 12 84 52 ± 15 70 * the f-ratio was 16.6 for group (p < 0.000009) and 1.8 for position (p = 0.08). neither the sum of 7 skinfold measurements (table iii) nor body fat percentage (table iv) were different between 16and 18-year-old rugby players. there were significant differences between positions, however, with props having a greater percentage of body fat and higher skinfold measurement than the other positions (tables iii and iv). there were significant differences between 16and 18 year-old groups regarding absolute and relative bench press measures (tables v and vi). the 16-year-old players lifted 77.1 ± 11.8 kg (6.55 ± 1.00 relative to adjusted body mass) while the 18-year-old group lifted 95.3 ± 16.7 kg (7.54 ± 1.30 relative to adjusted body mass). there were significant position differences in absolute bench press measures between props versus scrumhalves, flyhalves and wings, with the props displaying greater upper body strength for 1rm. pg38-45.indd 42 6/28/06 1:49:05 pm sajsm vol 18 no.2 2006 43 table ix. 10 meter speed (seconds) of 16-year-old (n = 79) and 18-year-old (n = 72) rugby players* position 16 years n 18 years n prop 2.0 ± 0.1 10 2.0 ± 0.1 11 hooker 1.9 ± 0.1 7 1.9 ± 0.1 4 lock 1.9 ± 0.1 8 1.9 ± 0.1 10 loose forward 1.9 ± 0.1 15 1.9 ± 0.1 13 scrumhalf 1.9 ± 0.1 4 1.8 ± 0.0 8 flyhalf 1.9 ± 0.1 5 1.9 ± 0.1 6 wing 1.8 ± 0.1 14 1.8 ± 0.1 9 centre 1.8 ± 0.1 10 1.8 ± 0.1 8 fullback 1.8 ± 0.1 6 1.8 ± 0.1 3 average 1.9 ± 0.1 79 1.9 ± 0.1 72 appropriate post-hoc analyses position main effects significance prop v. lock p < 0.003 prop v. loose forward p < 0.00002 prop v. scrumhalf p < 0.00001 prop v. flyhalf p < 0.0002 prop v. wing p < 0.00001 prop v. centre p < 0.00001 prop v. fullback p < 0.00005 lock v. wing p < 0.05 * the f-ratio was 0.15 for group (p = 0.70) and 10.60 for position (p < 0.001). table x. 40 meter speed (seconds) of 16-year-old (n = 79) and 18-year-old (n = 73) rugby players* position 16 years n 18 years n prop 5.8 ± 0.1 9 5.9 ± 0.2 11 hooker 5.6 ± 0.1 7 5.5 ± 0.4 4 lock 5.6 ± 0.2 8 5.6 ± 0.2 10 loose forward 5.5 ± 0.1 15 5.5 ± 0.2 13 scrumhalf 5.4 ± 0.2 5 5.4 ± 0.2 8 flyhalf 5.4 ± 0.1 5 5.4 ± 0.1 6 wing 5.3 ± 0.2 14 5.2 ± 0.1 9 centre 5.3 ± 0.0 10 5.3 ± 0.1 9 fullback 5.3 ± 0.2 6 5.3 ± 0.1 3 average 5.5 ± 0.2 79 5.5 ± 0.1 73 appropriate post-hoc analyses position main effects significance prop v. all positions p < 0.01 hooker v. wing p < 0.00005 hooker v. centre p < 0.002 hooker v. fullback p < 0.01 lock v. scrumhalf p < 0.01 lock v. wing p < 0.00001 lock v. centre p < 0.00001 lock v. fullback p < 0.003 loose forward v. wing p < 0.003 loose forward v. centre p < 0.05 * the f-ratio was 2.06 for group (p = 0.15) and 22.49 for position (p < 0.001). both age groups completed a similar number of pull-ups (10 ± 5 v. 11 ± 6 repetitions for 16v. 18-year-old groups). there were differences between props versus scrumhalves, wings and centres and between locks versus scrumhalves (table vii). the 18-year-old players completed more pushups (52 ± 15) than the 16-year-old players (41 ± 12; p < 0.000009). there were no differences between positions (table viii). speed was the same in both age groups when measured at 10 meters (1.9 ± 0.1 seconds) and 40 meters (5.5 ± 0.2 seconds). there were significant differences between positions, with props significantly slower than most other positions (tables ix and x). there were no differences in agility between the 16and 18-year-old groups (table xi). the props were less agile than scrumhalves, flyhalves, wings, centres and fullbacks. in the multistage shuttle run the 18-year-old group ran significantly more shuttles than the 16-year-old group (93.5 ± 15.3 v. 87.1 ± 19.4 shuttles; p < 0.05). props ran significantly fewer shuttles compared with loose forwards, scrumhalves, flyhalves and wings (table xii). discussion the 16and 18-year-old green squad players differed significantly in stature, body mass, arm strength (1 rm bench press and push-ups) and aerobic fitness (shuttle run) but not in percentage of body fat, speed (10 m and 40 m) or agility measures. these age group differences could be attributed to maturation, 13 training discrepancies 4 or a combination of the two. the stature of the 16-year-olds (175.6 ± 5.7 cm) and 18year-olds (179.2 ± 6.7 cm) was shorter than those reported in junior rugby league players (178 cm for 16-year-olds and 182 cm for 17-year-olds) and college rugby league players (181 cm for 20-year-old players) 2 and amateur rugby union players (184 cm). 16 the body mass of the 16-year-old (76.5 ± 8.2 kg) and 18year-old (84.9 ± 8.3 kg) players was heavier, 11 lighter 2 and comparable 4 with other junior rugby league players of similar ages. the 18-year-old green squad players were slightly heavier than amateur rugby players 20 years ago (84.4 kg), 16 pg38-45.indd 43 6/28/06 1:49:06 pm 44 sajsm vol 18 no.2 2006 table xi. illinois agility test results (seconds) for 16-year-old (n = 82) and 18-year-old (n = 50) rugby players* position 16 years n 18 years n prop 15.8 ± 0.7 10 16.3 ± 1.2 8 hooker 15.2 ± 0.8 7 14.9 ± 0.5 3 lock 15.5 ± 0.9 8 15.4 ± 0.6 9 loose forward 15.6 ± 0.9 15 15.0 ± 0.3 6 scrumhalf 14.6 ± 0.5 4 15.1 ± 0.3 6 flyhalf 14.7 ± 0.2 6 14.5 ± 0.4 3 wing 14.8 ± 0.5 15 14.4 ± 0.2 6 centre 15.2 ± 1.5 11 14.4 ± 0.4 7 fullback 14.7 ± 0.5 6 15.0 ± 0.7 2 average 15.2 ± 0.9 82 15.1 ± 0.8 50 appropriate post-hoc analyses position main effects significance prop v. scrumhalf p < 0.04 prop v. flyhalf p < 0.007 prop v.wing p < 0.0002 prop v. centre p < 0.0007 prop v. fullback p < 0.04 * the f-ratio was 0.66 for group (p = 0.42) and 5.69 for position (p < 0.001). table xii. the number of laps completed in the multistage shuttle run test for 16-year-old (n = 55) and 18-year-old (n = 63) rugby players* position 16 years n 18 years n prop 68.1 ± 13.0 9 77.6 ± 11.1 10 hooker 89.0 ± 7.6 5 92.8 ± 12.8 4 lock 89.8 ± 22.6 4 90.0 ± 10.6 9 loose forward 97.5 ± 24.0 11 94.8 ± 12.8 9 scrumhalf 85.7 ± 5.7 3 109.8 ± 12.0 6 flyhalf 98.3 ± 13.6 3 98.7 ± 14.3 6 wing 86.8 ± 9.7 8 99.9 ± 23.6 7 centre 86.6 ± 24.1 9 93.0 ± 10.1 9 fullback 92.0 ± 18.4 3 97.0 ± 3.5 3 average 87.1 ± 19.4 55 93.5 ± 15.3 63 appropriate post-hoc analyses position main effects significance prop v. loose forward p < 0.0007 prop v. scrumhalf p < 0.03 prop v. flyhalf p < 0.03 prop v. wing p < 0.03 * the f-ratio was 4.22 for group (p < 0.05) and 3.83 for position (p < 0.001). but obviously lighter than semi-professional and professional rugby players. 9 the 16-year-old group lifted less weight (77.1 ± 11.8 kg) than the 18-year-old group (95.3 ± 16.7) in the 1 rm bench press test for upper body strength. this age-specific weakness was documented by baker, 2 where performance in the 1 rm bench press was significantly correlated with playing achievement in untrained (70.0 kg), junior (85.0 kg), senior (98.2 kg), college (110.5 kg), and national (144.5 kg) level rugby league players (correlation coefficient r = 0.80). upper body strength was further disparate, with 16-yearold players completing fewer push-ups (41 ± 12) than the 18year-old players (52 ± 15). these junior players performed more push-ups however, than us national team rugby players. (33). 3 the 16-year-old group performed fewer shuttles (87.1 ± 19.4; estimated vo2peak 49 ml/kg/min) than the 18-year-old group (93.5 ± 15.3; estimated vo2peak 51 ml/kg/min). 15 this finding may be a result of maturation, where vo2 continues to increase through the age of 18, 13 combined with genetic limitations governing oxygen consumption. 5 training may also influence vo2max, contributing to approximately 35% of the variance of the increase. these measures of aerobic capacity are higher than those reported in junior and amateur rugby league players from australia 11,12 but lower than those values reported in other national team players. 16 the number of pull-ups, sum of 7 skinfolds, per cent body fat, agility and speed were not significantly different between the two age groups. of particular interest, both groups of players displayed the same average speed at 10 m (1.9 seconds) and 40 m (5.5 seconds). these times are slower than those reported in professional rugby league players (1.71 and 5.32 s) 1 but faster than those reported in australian elite junior and semi-professional rugby league players. 11,12 positional differences were reported in measures of stature, body mass, sum of 7 skinfolds, per cent body fat, bench press (absolute), pull-ups, 10 m and 40 m speed, agility and aerobic fitness. a majority of these differences occurred between forward and back-line players with props having the most body fat, best upper body strength, slowest speed, least agility and lowest aerobic fitness of most other rugby players. these findings support another study which showed the props were the heaviest, slowest and least aerobically fit players, but outperformed all other players in measures of strength and power. 19 this coincides with the particular demands of this position, where a high degree of body fat aids in absorbing impact during tackles and collisions while maximum strength and power are assets when competing for the ball in rucks, scrums and mauls. heart rate and time motion analyses of under-19-year-old australian rugby pg38-45.indd 44 6/28/06 1:49:06 pm sajsm vol 18 no.2 2006 45 players indicate that front row (props and hookers) and back row (locks and loose forwards) forwards spend the most time in high exertion (58% and 56% respectively at 85 95% hrmax) but cover the least distance (4 400 and 4 080 m) compared with inside (centres and flyhalves: 41% at 85 95% hrmax, 5 530 m) and outside (wings and fullbacks: 34% at 85 95% hrmax, 5 750 m) backs. 6 these differences help explain the distinct physical characteristics necessary to succeed as a player in a particular position, thereby contributing to team success. conversely, backs are the shortest and lightest of rugby players. inside, midfield and outside backs possess superior speed and agility to move the ball forward, accelerate away from defenders and out-manoeuvre opponents. 9 these criteria are supported in our findings where backs are significantly faster, more agile and aerobically fit than forwards, particularly when compared with props. it is also of interest to note that locks were significantly taller than all other rugby positions. this finding is consistent with other reports and exemplifies the specific demands placed on these players to jump to receive balls at lineouts. 9 in conclusion, there are differences between elite 16and 18-year-old rugby players with respect to stature, body mass, arm strength (1 rm bench press and push-ups) and aerobic fitness (shuttle run) but not in percentage of body fat, speed (10 m and 40 m) or agility measures. positional differences exist, with props having the most body fat, best upper body strength, slowest speed, least agility and lowest aerobic fitness of most other rugby players. this descriptive report provides a template for the evaluation of junior rugby players as well as baseline data for further study on the developmental characteristics and physiological progression of elite rugby athletes. acknowledgements this study was funded by the south african rugby green squad programme and discovery health, the medical research council of south africa and the nellie atkinson and harry crossley research funds of the university of cape town. references 1. baker d, nance s. the relation between running speed and measures of strength and power in professional rugby league players. j strength cond res 1999; 13: 230 5. 2. baker d. differences in strength and power among junior-high, senior-high, college-aged, and elite professional rugby league players. j strength cond res 2002; 16: 581-5. 3. carlson br, carter je, patterson p, petti k, orfanos sm, noffal gj. physique and motor performance characteristics of us national rugby players. j sports sci 1994; 12: 403-12. 4. coutts aj, murphy aj, dascombe bj. effect of direct supervision of a strength coach on measures of muscular strength and power in young rugby league players. j strength cond res 2004; 18: 316-23. 5. danis a, kyriazis y, klissouras v. the effect of training in male prepubertal and pubertal monozygotic twins. eur j appl physiol occup physiol 2003; 89: 309-18. 6. deutsch mu, maw gj, jenkins d, reaburn p. heart rate, blood lactate and kinematic data of elite colts (under-19) rugby union players during competition. j sports sci 1998; 16: 561-570. 7. dooman cs, vanderburgh pm. allometric modeling of the bench press and squat: who is the strongest regardless of bodymass? j strength cond res 2000; 14: 32-6. 8. durnin jvga, womersley j. body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. brit j nutr 1974; 32: 77-97. 9. duthie g, pyne d, hooper s. applied physiology and game analysis of rugby union. sports med 2003; 33: 973-91. 10. duthie gm. a framework for the physical development of elite rugby union players. international journal of sports physiology and performance 2006; 1: 2-13. 11. gabbett tj. physiological characteristics of junior and senior rugby league players. br j sports med 2002a; 36: 334-9. 12. gabbett tj. influence of physiological characteristics on selection in a semi-professional first grade rugby league team: a case study. j sports sci 2000b; 20: 399-405. 13. geithner ca, thomis ma, van den eynde b, et al. growth in peak aerobic power during adolescence. med sci sports exerc 2004; 36: 1616-24. 14. getchell b. physical fitness: a way of life, 2nd ed. new york: john wiley and sons, inc., 1979. 15. lèger la, mercier d, gadoury c, lambert j. the multistage 20 metre shuttle run test for aerobic fitness. j sports sci 1988: 6: 93-101. 16. maud pj. physiological and anthropometric parameters that describe a rugby union team. br j sports med 1983: 17: 16-23. 17. pienaar ae, spamer mj, steyn hs jun. identifying and developing rugby talent among 10-year-old boys: a practical model. j sports sci 1998; 16: 691-9. 18. quarrie kl, handcock p, waller ae, chalmers dj, toomey mj, wilson bd. the new zealand rugby injury and performance project. iii. anthropometric and physical performance characteristics of players. br j sports med 1995; 29: 263-70. 19. quarrie kl, handcock p, toomey mj, waller ae. the new zealand rugby injury and performance project. iv. anthropometric and physical performance comparisons between positional categories of senior a rugby players. br j sports med 1996; 30: 53-6. 20. ross wd, marfell-jones mj. kinanthropometry. in: macdougall jd, wenger ha, green hj, eds. physiological testing of the high-performance athlete. champaign, il, usa: human kinetics books, 1991, 223-308. pg38-45.indd 45 6/28/06 1:49:06 pm 114 sajsm vol. 27 no. 4 2015 original research hip and groin pain in sub-elite south african footballers d j dowson,1 mbbch; h bayne,2 phd; c c grant,1 phd 1 section sports medicine, university of pretoria, south africa 2 high performance centre, university of pretoria, south africa corresponding author: d j dowson (donna@drdowson.co.za) background. groin injuries are common in football. this can be attributed to the nature of the sport involving rapid accelerations, decelerations, abrupt directional changes and kicking. groin injuries require lengthy rehabilitation times and predispose players to further injuries. previous groin injury is a risk factor for future groin injuries, suggesting players are inadequately rehabilitated or the original cause has not been addressed. objectives. to describe the prevalence, nature and treatment patterns of groin injuries in sub-elite players, and to investigate differences in hip strength and range of motion between players with and without a history of groin injury. method. thirty sub-elite, senior university male players were interviewed and questioned regarding groin injuries sustained in the preceding three years. they were assessed using the hagos questionnaire, and underwent isokinetic hip flexion/extension strength, adductor squeeze and range of motion tests. results. seventeen players (57%) reported having a previous groin injury, with an average score of 83 (16) [mean (sd)] on the hagos, compared with 92 (5) for non-injured players. of the previously injured players, 29% did not seek treatment from a medical professional. injuries included adductor strain (35%), inguinal-related (18%), iliopsoas-related (12%) and hip joint pathology (6%). the average time off was 25 days. there were no significant differences in isokinetic hip flexion/extension strength, adductor strength and range of motion. conclusion. the prevalence of groin injuries in this population is relatively high (57%) and requires lengthy rehabilitation time. the hagos is a suitable tool to identify groin pain in this population within the sports and recreation and quality of life subscales. isokinetic hip strength and range of motion testing lacked sensitivity in detecting deficits in players with a previous groin injury. only two-thirds of injured players consulted a medical practitioner, increasing the likelihood that rehabilitation was inadequate. it is therefore recommended that player/coach education regarding injury management improve in order to reduce subsequent injuries. keywords. hagos, groin injury, prevalence, range of motion, isokinetic strength s afr j sports med 2015;27(4):114-117. doi:10.17159/2078-516x/2015/ v27i4a425 the sport of football involves repetitive changes of direction, rapid acceleration and deceleration, and kicking. these multidirectional and multi-planar movements place substantial load on the hip region. hip and groin injuries are common in football, with reported annual incidences of 5-28%[1] and nearly one-third of all players will experience a groin injury during the course of their careers.[2] in most cases, players return to play after less than four weeks[3] but some injuries persist and can lead to long-standing disability with lengthy absences from sport.[1] the typical groin injury involves one or more anatomical structures in the groin region. recent consensus[4] describes categorisation of groin injuries based on the involved clinical entities: adductorrelated, iliopsoas-related, inguinal-related, pubic-related and hip-related groin pain. there is acknowledgement that multiple pathologies can coexist in patients with chronic groin pain, with hip joint pathology thought to be a major contributor to secondary breakdown of adjacent structures.[5] the copenhagen hip and groin outcome score (hagos) is a self-reported questionnaire evaluating hip and groin disability status on a scale from 0 to 100, where a score of 100 indicates no hip and groin problems and 0 indicates severe problems.[6] the questionnaire consists of six separate subscales for the assessment of the following: symptoms, pain, physical function in daily living, physical function in sports and recreation, participation in physical activities, and hip and/or groin-related quality of life. each subscale is scored as a percentage of the total possible score.[6] the hagos questionnaire therefore allows for an objective measure of a subjective perception. thorborg et al. recently evaluated 444 football players, who were hip and groin injury-free to establish reference values for the hagos in injury-free male football players.[6] the mean reference ranges for injury-free football players with no pain, including no pain from the previous season, was a score of 100 in all categories except in the symptoms subscale, where the average score was 89%.[6] a number of risk factors for groin injuries in football players have been established. these include a history of previous groin injury,[7] decreased adductor muscle strength,[7,8] decreased hip abduction range of motion, decreased levels of sports specific training, abdominal muscle recruitment, limb length discrepancy and pelvic instability.[7] there is little data in the literature analysing the cause as to why a previous groin injury will predispose a player to another groin injury. isokinetic assessment is currently the reference method for measuring dynamic muscle strength.[9] isokinetic testing has been used to define normative values of hip muscle strength in uninjured football players, not only to identify players at risk but also to aid in return to play decisions following groin injuries.[10] it has been demonstrated that hip range of motion was reduced in football players with current long-standing groin pain.[8] preliminary work done in a small study group associated hip stiffness with an increased incidence of groin injury.[11] the focus of this study was to describe the prevalence, nature and treatment patterns of groin injuries in sub-elite players, to examine hip and groin disability scores, and to investigate differences in strength and range of motion in players with and without a history of groin injury. methods thirty male senior league university football players from within gauteng, south africa, were invited to participate in the study. the mailto:donna@drdowson.co.za http://dx.doi.org/10.17159/2078-516x/2015/v27i4a425 http://dx.doi.org/10.17159/2078-516x/2015/v27i4a425 sajsm vol. 27 no. 4 2015 115 participants train on average five times a week for 90 minutes a session with one to two 90 minute matches a week. ethical approval was obtained from the research ethics committee, faculty of health sciences of the university of pretoria and each player gave written consent. a personal interview was conducted with each player to obtain injury history information, including whether they had ever suffered a groin injury in the previous three years, which medical professional(s) had been consulted after the injury, the diagnosis, and time until return to play. players also completed the hagos questionnaire.[6] players with a history of groin injury were allocated to the case group and the remainder to the control group. isokinetic hip flexion and extension strength was tested in the supine position with a biodex® isokinetic dynamometer (shirley, new york, usa). the protocol consisted of concentric testing of the hip flexors and extensors at 60°/s and eccentric testing of the hip flexors at 60°/s. hip adductor muscle strength was measured using a sphygmomanometer, with the player in a supine position with his knees bent at 90°.[8] hip extension range of motion was assessed using the thomas test; with the player supine at the edge of the plinth and both hips flexed simultaneously to their limit, thus removing lumbar lordosis. whilst stabilising the non-tested hip firmly in position to maintain pelvic tilt, the limb being tested was lowered over the edge of the plinth and the hip extension angle measured with a goniometer.[12] hip rotation range of motion was assessed with the player in the prone position with the knee flexed at 90°. the tested limb was rotated internally and externally until resistance was met and measured with a goniometer.[12] the bent knee fall out (bkfo) test was performed with the player supine and the tested hip flexed to 45° and the knee flexed to 90°. the knee was allowed to fall laterally and gentle over pressure (ddi) applied to make sure the participant was relaxed at the limit of movement. the distance between the plinth and the lateral surface of the knee at the level of the fibula head was measured.[8] data from the case group’s injured side were compared against the dominant leg of the control group. data analysis consisted of descriptive statistics to summarise the data and independent samples t-tests. statistical significance was accepted at p<0.05. results seventeen players (57%) reported having experienced a previous groin injury within the last three years of play. of these, six (35%) had sustained an adductor-related injury, three (18%) sustained an inguinal-related injury, two (12%) sustained an iliopsoas-related injury, two (12%) involved the hip joint, and four (23%) were unspecified. three players (18%) reported having experienced multiple groin injuries. the average time before return to play was 25 days, with ranges from three days to four months. a total of 30% of players had severe injuries (>28 days), 30% had moderate injuries (7-28 days) and 40% had mild injuries (<7 days). eleven (65%) of the injured players sought treatment from a physiotherapist for their injuries, five (29%) did not have any treatment and only one (6%) consulted a sports physician. there were no statistically significant differences between the case and control groups for age, height or mass (table 1), nor for any of the range of motion or strength variables assessed (figure 1). previously injured players reported significantly lower hagos scores in the sports and recreation subscale (case 80.1 (18.1); control 92.6 (6.4); t=2.560; p=0.019) and quality of life subscale (case 75.3 (15.5); control 87.7 (13.1); t=2.281; p=0.031) (figure 2). table 1. comparison of descriptive values, previously injured versus control group case control mean sd mean sd t p age (years) 21.6 1.5 21.1 1.9 -.806 .427 height (cm) 175.8 12.5 174.0 5.4 -.485 .631 mass (kg) 69.7 8.0 66.3 6.6 -1.244 .224 0 25 50 75 100 125 150 175 200 225 250 pr es su re (m m h g) adductor squeeze test -25 -20 -15 -10 -5 0 5 10 15 d eg re es (° ) … thomas test 0 5 10 15 20 25 30 35 40 45 50 d eg re es (° ) hip internal rotation range of motion 0 5 10 15 20 25 30 35 40 45 50 d eg re es (° ) hip external rotation range of motion 0 2 4 6 8 10 12 14 16 18 20 22 24 d is ta nc e (c m ) bent knee fall out 0 50 100 150 200 250 300 pe ak t or qu e/ bo dy m as s (% ) hip flexion peak torque 0 50 100 150 200 250 300 350 400 pe ak t or qu e/ bo dy m as s (% ) hip extension peak torque 0 50 100 150 200 pe ak t or qu e/ bo dy m as s (% ) eccentric hip flexion peak torque fig. 1. range of motion and strength results for case group (previously injured) and control group case group: × control group: • 116 sajsm vol. 27 no. 4 2015 50 55 60 65 70 75 80 85 90 95 100 sc or e hagos average 50 55 60 65 70 75 80 85 90 95 100 sc or e hagos pain 50 55 60 65 70 75 80 85 90 95 100 sc or e hagos symptoms 50 55 60 65 70 75 80 85 90 95 100 sc or e hagos activities of daily living 50 55 60 65 70 75 80 85 90 95 100 sc or e hagos sport & recreation * 50 55 60 65 70 75 80 85 90 95 100 sc or e hagos physical activity 50 55 60 65 70 75 80 85 90 95 100 sc or e hagos quality of life * fig. 2. hagos values for case group (previously injured) and control group case group: × control group: • * significantly different from control, p<0.05] discussion the findings of this study confirmed the hagos as a responsive measure of hip and groin disability outcome and injury status in this population, specifically in the sports and recreation and quality of life subscales. hagos is the only patient reported outcome questionnaire aimed at young to middle-aged adults presenting with groin pain[14] and it has been proven to be valid, reliable and responsive for evaluating individuals with hip and/or groin pain, including male soccer players.[6] the hagos is designed to identify current symptoms, and this research suggests that previously injured players do still suffer from persistent subjective symptoms that affect the players defined sports and recreation and quality of life subscales. it has been suggested that one in three football players will experience a groin injury during their careers.[2] the incidence reported in this study was substantially higher than this figure, with 57% of players having suffered from a groin injury in their careers thus far. this may be due, in part, to the subjective nature of injury history recall that was relied upon in the current study. nevertheless, the hagos results substantiate the players’ recall of a previous groin injury. adductor-related injury was the most common diagnosis. this is comparable to similar studies that suggest adductor-related injuries account for between 51%[16] and 64%[1] of groin injuries. an important concern identified in this study is that almost a third of players (29%) did not seek medical attention for their injuries. their general view was that ‘rest and stretches’ would be adequate. yet the time off from play was significant, with an average of 25 days. vague symptoms and an insidious onset of groin pain allows players to train and play with pain, which may result in the player delaying seeking immediate medical attention, thus often leading to a chronic presentation.[13] hölmich and thorborg categorised mild groin injuries as 4-7 days injury time, moderate groin injuries as 8-28 days injury time and more than 28 days as severe.[16] in this study 30% of players had severe injuries, 30% had moderate injuries and 40% had mild injuries. this is comparable to a large study involving 907 sub-elite football players of which 43% sustained moderate injuries and 33% sustained severe injuries.[16] previous research has identified significant differences in hip adductor strength and range of motion between uninjured footballers and symptomatic players with long-standing groin pain.[8] in the current study, players with a history of groin injury were asymptomatic at the time of testing, which may explain why these findings do not replicate this result. the adductor squeeze values were lower than those reported in previous research in gaelic football players, where the control group attained adductor squeeze strength values of 269.3 ± 25.4 mmhg, and the injured group attained values of 202.9 ± 36.7 mmhg.[8] another study recorded values of 209 mmhg ± 42.3 in groin pain free elite football players compared to 180.5 ± 30.2 in players with groin pain.[15] allowing for measurement error and variation, it has been suggested that a threshold of 200 mmhg may be useful clinically.[13] limitations of this study include the small sample size and subjective nature of patient injury history recall, which may have influenced the validity of the clinical entity diagnosis reported. however, the injury data obtained from the players agrees with the typical distribution of clinical presentation of groin injury. conclusion groin injuries are more common in sub-elite south african footballers than has been reported in previous literature on footballrelated injury. the hagos is a suitable tool to identify groin pain in this population within the sports and recreation and quality of life subscales. isokinetic hip strength and range of motion testing lacked sensitivity in detecting deficits in players with a previous groin injury. a new and important finding was that almost a third (29%) of players did not seek treatment from a qualified professional, and sajsm vol. 27 no. 4 2015 117 only 6% of players consulted a sports physician. this represents suboptimal injury management. the study concludes that player and coach education on appropriate injury management strategies is necessary. this should include guidance on injury prevention interventions, and the proper pathways to follow for treatment and rehabilitation of injuries. references 1. werner j. uefa injury study: a prospective study of hip and groin injuries in professional football over seven consecutive seasons. br j sports med 2009;43(13): 1036-1040. [http://dx.doi.org/10.1136/bjsm.2009.066944] 2. kinchington m. groin pain: a view from below; the impact of lower extremity function and podiatric interventions. aspetar sports med j 2013;2(3):360-368. 3. ekstrand j, hägglund m, walden m. epidemiology of muscle injuries in professional football (soccer). am j sports med 2011;399(6):1266. [http://dx.doi. org/10.1177/0363546510395879] 4. weir a, brukner p, delahunt e, et al. doha agreement meeting on terminology and definitions in groin pain in athletes. br j sports med 2015;49(12):1-8. [http://dx.doi. org/10.1136/bjsports-2015-094869] 5. rankin a, bleakley c, cullen m. hip joint pathology as a leading cause of groin pain in the sporting population. am j sports med 2015;43(7):1698-1703 [http://dx.doi. org/10.1177/0363546515582031] 6. thorborg k, branci s, stensbirk f, et al. copenhagen hip and groin outcome score (hagos) in male soccer: reference values for hip and groin injury-free players. br j sports med 2014;48(7):557-559. [http://dx.doi.org/10.1136/bjsports-2013-092607] 7. garvey jfw, read jw, turner a. sportsman hernia: what can we do? hernia 2010;14(1):17-25. [http://dx.doi.org/10.1007/s10029-009-0611-1] 8. nevin f, delahunt e. adductor squeeze test values and hip joint range of motion in gaelic football athletes with longstanding groin pain. j  sci med sport 2014;17(2): 155-159. [http://dx.doi.org/10.1016/j.sams.2013.04.008] 9. julia m, dupeyron a, laffont i, et al. reproducibility of isokinetic peak torque assessments of the hip flexor and extensor muscles. ann phys rehabil med 2010;53(5):293-305. [http://dx.doi.org/10.1015/j.rehab/2010.95.002] 10. hanna cm, fulcher ml, elley cr, moyes sa. normative values of hip strength in adult male association football players assessed by handheld dynamometry. j  sci med sport 2010;13(3):299-303. [http://dx.doi.org/10.1016/j.sams.2008.11.007] 11. verrall g, slavotinek j, barnes p, esterman a, oakeshott r, spriggins a. hip joint range of motion restriction precedes athletic chronic groin injury. j sci med sport 2007;10(6):463-466. [http://dx.doi.org/10.1016/j.sams.2006.11.006] 12. appley ag, solomon l. concise system of orthopaedics and fractures. 2nd ed. arnold;2001:174-177. 13. brukner p, khan k. brukner & khan’s clinical sports medicine. 4th ed. australia: mcgraw-hill education;2013:558-568. 14. thorborg k, tijssen m, habets b, bartels e, roos e, hölmich p, et al. patientreported outcome (pro) questionnaires for young to middle-aged adults with hip and groin disability: a systematic review of the clinimetric evidence. br j sports med 2015;49(12):1-11. [http://dx.doi.org/10.1136/bjsports-2014-094224] 15. malliaras p, hogan a, nawrocki a, crossley k, schache a. hip flexibility and strength measures: reliability and association with athletic groin pain. br j sports med 2009;43(10):739-744. [http://dx.doi.org/10.1136/bjsm.2008.055749] 16. hölmich p, thorborg k, dehlendorff c, et al. incidence and clinical presentation of groin injuries in sub-elite male soccer. br j sports med 2014;48:1245-1250. [http:// dx.doi.org/10.1136/bjsports-2013-092627] http://dx.doi.org/10.1136/bjsm.2009.066944 http://dx.doi.org/10.1177/0363546510395879 http://dx.doi.org/10.1177/0363546510395879 http://dx.doi.org/10.1136/bjsports-2015-094869 http://dx.doi.org/10.1136/bjsports-2015-094869 http://dx.doi.org/10.1177/0363546515582031 http://dx.doi.org/10.1177/0363546515582031 http://dx.doi.org/10.1136/bjsports-2013-092607 http://dx.doi.org/10.1007/s10029-009-0611-1 http://dx.doi.org/10.1016/j.sams.2013.04.008 http://dx.doi.org/10.1015/j.rehab/2010.95.002 http://dx.doi.org/10.1016/j.sams.2008.11.007 http://dx.doi.org/10.1016/j.sams.2006.11.006 http://dx.doi.org/10.1136/bjsports-2014-094224 http://dx.doi.org/10.1136/bjsm.2008.055749 http://dx.doi.org/10.1136/bjsports-2013-092627 http://dx.doi.org/10.1136/bjsports-2013-092627 _goback original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license injury incidence and burden during senior inter-provincial field hockey tournaments n pereira,1 msc; tl burgess,1,2 phd; l corten,3 phd 1 division of physiotherapy, faculty of health sciences, university of cape town, south africa 2 centre for medical ethics and law, faculty of medicine and health sciences, stellenbosch university, cape town, south africa 3 division of physiotherapy, school of health sciences, university of brighton, united kingdom corresponding author: n pereira (nick@enhancedphysio.co.za) field hockey is an olympic discipline played widely across the world at various levels.[1] in south africa, the sport is growing with increasing participation from primary and secondary school to senior provincial level. it is a high-speed team sport, consisting of short bursts of sprinting with technical coordination of a stick and ball, while executing a coach’s tactical game plan. [2-4] the senior inter-provincial tournament (ipt) is the elite level of south african field hockey and takes place annually. teams play several matches over a period of a week, including a round robin, playoffs, and a final. the tournaments observed in this study were held separately during 2018 in kwazulu natal. from this tournament, the national teams are selected for international events, including the world cup and olympic games. to date, there are few published studies which have been undertaken in south africa exploring injury incidence. the existing research is challenging to compare due to the heterogeneity of research methodologies. research into a local female provincial hockey season during 2004 reported injury incidence to be 6.3 per 1 000 hours played.[5] injury data collected from the international federation for field hockey (fih) tournaments report the incidence of injury to be 26.0-29.1 per 1 000 hours for females and between 20.8-90.9 per 1 000 hours for males.[1] the definitions used in these studies are in stark contrast, making the comparison regarding injury incidence challenging. research in field hockey in south africa is limited when compared to football and rugby due to a lack of funding and the amateur status of the sport. [6-7] there is currently no data available on injury incidence to male south african field hockey players, and no incidence literature for field hockey has been published in south africa since 2007. there are no associated statistics established for this population; therefore, the aim of this study was to observe the current injury incidence and burden in south african field hockey, as well as the association of previous injury and gender with incidence by conducting this study at the annual ipt. methods ethical approval the study was approved by the university of cape town’s faculty of health sciences human research ethics committee (hrec ref: 117/2018) and by the ceo of the south african hockey association (saha). study design and setting the study was quantitative, descriptive, and longitudinal. it took place at two separate tournaments in 2018, namely, the male and female ipts held in pietermaritzburg and durban, respectively. all players attending these tournaments were invited to enrol in the study. procedure identification of participants was carried out by contacting saha and subsequently, the provincial unions. informed consent forms and baseline questionnaires were disseminated by the participating unions. participants who did not respond to the research invitation were approached and recruited during a pre-tournament briefing at the venue in the days preceding commencement. participants were excluded if they were under the age of 18 years or did not provide consent to be involved in the study. background: field hockey is an olympic sport played internationally and in which south africa is a participating nation. it also has its own world cup. few injury studies have been published on south african field hockey. research efforts should increase within the sport to ensure safe participation and mitigate the inherent injury risks. objectives: the objective of the study was to attend the male and female inter-provincial field hockey tournaments in south africa and determine the incidence of injury and burden of acquired sport injuries (time-loss and medical attention). methods: a quantitative, descriptive, longitudinal study, including 133 females and 139 males, was conducted. participants completed baseline questionnaires prior to the tournament and post-match questionnaires detailing injuries during the tournament. results: the recorded injuries were 77.9 (females) and 99.5 (males) per 1 000 player match hours. medical attention was 51.9 (females) and 70.3 (males) injuries per 1 000 player match hours. the result for time-loss injuries was 4.3 (females) and 7.5 (males) injuries per 1 000 player match hours. discussion: the study found high incidence rates of all injuries and medical attention injuries; however, the incidence of time-loss injuries was low in comparison to existing literature. comparing current results to existing literature is challenging due to the heterogeneity of methodologies and injury definitions in field hockey research. conclusion: this was the largest observational study in field hockey conducted in south africa. the international sporting body should establish a consensus for future research and the south african hockey association explore long-term surveillance in south africa to mimic similar national codes. keywords: injury burden, injury prevention, gender, south african field hockey s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a11832 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a11832 https://orcid.org/0000-0002-3110-2195 https://orcid.org/0000-0003-0279-8610 https://orcid.org/0000-0001-9796-2182 original research sajsm vol. 33 no. 1 2021 2 measurement instrument players were asked to complete a self-designed questionnaire prior to the tournament to gather background information such as age and previous injury history. during the tournament, the players were also asked to complete daily self-reporting of injuries after each match using a digital injury reporting form. the results from both questionnaires were collated, de-identified, and coded for analysis. as there is currently no consensus on injury surveillance for field hockey. the questionnaires were based on the boksmart injury surveillance forms, a questionnaire used in the south african rugby union injury surveillance report.[7] the injury definition was adapted from the federation internationale de football association (fifa) medical assessment and research centre. [7, 8] the following definition was used in this study: ’any physical discomfort resulting from hockey-related activity, regardless of severity or need for medical attention as perceived by the player. ‘[8] injuries were categorised into one of three categories: “all injuries”, includes any and all physical complaints reported by participants regardless of severity or need for medical attention; “medical attention injuries”, injuries requiring evaluation or treatment from a health professional; and “time-loss injuries”, injuries that cause inability to participate in training or matches. statistical analysis incidence was calculated as follows: each team had 11 players on the field during a match, with a total match duration of one hour (four 15-minute quarters). the tournament was played over seven days and regardless of progression through the tournament, each team played on all seven match days. player-match-hours was therefore calculated as: 11 players x 7 days x 1h per game = 77 player-match-hours. incidence is presented as injuries per 1 000 playermatch hours, with 95% confidence intervals. the descriptive data were not normally distributed based on the shapiro-wilk test; therefore, the data are presented as median and interquartile ranges. associative analysis in statistics was performed using the chisquared test, odds ratio, and risk ratio to assess previous injuries and incidence, and to compare the male and female tournament incidence. statistical analyses were performed using statistical software ibm spss version 25 (armonk, ny: ibm corp). results study sample the study enrolled 272 participants (133 females, 139 males) attending the 2018 ipt. the players’ ages across the two tournaments were not normally distributed (w = 0.90, p < 0.01). the ages of participants showed a median (interquartile range) age of 22 (20-26) years for males and 21 (1925) years for females. in the female tournament, 163 participants completed the tournament injury reporting form; 23 participants did not provide informed consent and their data were excluded. seven participants were excluded due to being underage. in the male tournament, 168 participants completed the injury reporting form, but 29 did not complete the consent form and their data were excluded from the study. the recruitment flowchart is presented in fig. 1. response rate the results relied on the participants completing daily injury report forms. the variation in response rate per day is presented in fig. 2. the male participants’ reporting began with 93 responses on day one (67% of recruited sample), and steadily decreased to 52 (37% of recruited sample) on the final day of the tournament. the female participants’ reporting began with 74 responses (55% of recruited sample), increased to 86 (64% of recruited sample) on day two, and then decreased to 70 (52% of recruited sample) for day three. fig. 1. recruitment flowchart fig. 2. number of injury report forms per match day original research 3 sajsm vol. 33 no. 1 2021 incidence of injury in the female tournament, a total of 72 injuries were reported, with 48 requiring medical attention, and four resulting in time-loss (table 1). the incidence calculated per 1 000 player match hours was 77.9 (95% ci: 47.1 108.1) for the overall female tournament, with 51.9 (95% ci: 32.3 71.5) injuries per 1 000 player match hours requiring medical attention, and 4.32 (95% ci: 1.04 9.7) injuries per 1 000 player match hours resulting in time-loss. it should be noted that teams are anonymised and numbered one to thirteen. the same numbers from both male and female tournament represent the same province. numbers twelve and thirteen represent different provinces. a total of 92 injuries were reported in the male tournament, with 65 injuries requiring medical attention and seven resulting in time-loss. the incidence of injuries for the male tournament was 99.5 (95% ci: 71.9 127.1) injuries per 1 000 player match hours. the incidence of medical attention needed was 70.3 (95% ci: 46.1 94.4) injuries per 1 000 player match hours, and the incidence of time-loss was 7.5 (95% ci: -0.7 15.75) injuries per table 2. male tournament injury incidence team all injuries incidence per 1 000 player match hours medical attention needed medical attention incidence per 1 000 player match hours timeloss incidence of timeloss per 1 000 player match hours 1 5 64.9 2 25.9 0 0 2 4 51.9 3 38.9 1 12.9 3 8 103.8 4 51.9 0 0 4 10 129.8 5 64.9 0 0 5 12 155.8 7 90.9 2 25.9 6 2 25.9 2 25.9 0 0 7 10 129.8 8 103.8 0 0 8 13 168.8 11 142 1 12.9 9 8 103.8 7 90.9 0 0 10 5 64.9 4 51.9 0 0 11 9 116.8 9 116.8 3 38.9 13 6 77.9 3 38.9 0 0 total 92 99.5 (95% ci: 71.9 – 127.1) 65 70.3 (95% ci: 46.1 – 94.4) 7 7.5 (95% ci: -0.7 – 15.8) injury data are presented as individual team and total injury numbers and incidence rates per 1000 player match hours. injuries were categorised into one of three categories: “all injuries”, includes any and all physical complaints reported by participants regardless of severity or need for medical attention; “medical attention injuries”, injuries requiring evaluation or treatment from a health professional; and “time-loss injuries”, injuries that cause inability to participate in training or matches. each team number represents a provincial team, team 12 did not participate in the male tournament. table 1. female tournament injury incidence team all injuries incidence per 1 000 player match hours medical attention needed medical attention incidence per 1 000 player match hours timeloss incidence of timeloss per 1 000 player match hours 1 10 129.8 7 90.9 0 0 2 4 51.9 3 38.9 0 0 3 10 129.8 5 64.9 1 12.9 4 0 0 0 0 0 0 5 5 64.9 2 25.9 0 0 6 8 103.8 8 103.8 2 25.9 7 6 77.9 6 77.9 0 0 8 5 64.9 4 51.9 0 0 9 2 25.9 1 12.9 0 0 10 5 64.9 3 38.9 0 0 11 4 51.9 4 51.9 0 0 12 13 168.8 5 64.9 1 12.9 total 72 77.9 (95% ci: 47.1-108.1) 48 51.9 (95% ci: 32.3-71.5) 4 4.3 (95% ci: -1.04-9.7) injury data are presented as individual team and total injury numbers and incidence rates per 1000 player match hours. injuries were categorised into one of three categories: “all injuries”, includes any and all physical complaints reported by participants regardless of severity or need for medical attention; “medical attention injuries”, injuries requiring evaluation or treatment from a health professional; and “time-loss injuries”, injuries that cause inability to participate in training or matches. each team number represents a provincial team, team 13 did not participate in the female tournament. original research sajsm vol. 33 no. 1 2021 4 1 000 player match hours (table 2). association of injuries there were several associative statistics explored in the original study; however, previous injury as well as gender differences for injury have been outlined in table 3. there is a statistically significant association for players who reported injury in the pre-tournament and during the tournament. there are no statistically significant associations between injuries in the male and female tournaments respectively. discussion incidence of injury the primary aim of this study was to investigate the incidence of injury in field hockey during the senior male and female provincial tournaments of 2018. the injury incidence rates found in this study (99.5 and 77.9 injuries per 1 000 player match hours for males and females respectively) are higher than those found in literature investigating the fih international tournaments of 2013 [1]. it was found that injury incidence in this study ranged between 26.0-29.1 per 1 000 player match hours for females and between 20.8-90.9 per 1 000 player match hours for males. there are significant methodological and contextual differences between the present study and the fih tournaments literature, namely in the injury definitions used and the classification of injuries. the present study captured all self-reported injuries regardless of subsequent time-loss or the need for medical attention and is thus expected to observe higher incidence rates. the 2013 fih tournament’s study captured injuries that required stoppage in play, resulting in the removal of the player from the field.[1] furthermore, the fih study captured injuries recorded by match officials, with players and medical staff not involved in the study. the number of injuries resulting in time-loss or players receiving medical attention was not reported in the fih study. the only other published south african study on the incidence of injury in field hockey investigated ankle strength, proprioception, and injury incidence in a sample of 47 female provincial hockey players.[5] although their method of capturing injuries also utilised self-reporting, their injury definition only included injuries resulting in time-loss from field hockey for five or more days and relied on participant recall post season. their incidence of injury of 6.32 per 1 000 player match hours is partially comparable with the present study’s time-loss injury incidence of 4.3 per 1 000 player match hours for females. however, it is inappropriate to draw meaningful comparisons between the two studies due to differences in study methodology. the incidence of time-loss injuries in the male tournament cannot be compared to other research in south africa, as no available studies have investigated injury incidence in males. injury burden the present study observed a decrease from self-classified injuries to medical attention injuries, and then to time-loss injuries. the burden of time-loss injury was low in both tournaments with females reporting 4.32 per 1 000 player match hours and 7.5 per 1 000 player hours for males. this supports the views of international research that time-loss from field hockey is relatively low.[9] a study observing american female collegiate field hockey players over a ten-year period reported an overall injury incidence of 5.36 per 1 000 player hours (training and competition), and 8.49 per 1 000 player match hours for competition only.[10] injuries in this study were defined as injury caused by field hockey, requiring medical attention and resulting in at least one day of missed training or match participation. although the definition of injury in this study varies, there is a comparable time-loss incidence rate with the female tournament of the present study. a hypothesis for the injury/time-loss mismatch is the competitive nature of athletes, and the level of participation in the present study.[13] after participating in the senior ipt, the male and female national teams are selected. this may have led to participants ’playing through injury.’ [3] there is no association between ’playing through injury’ and match outcomes, although there are certainly long-term health concerns for participants who use this approach. medical attention and time-loss injuries observed were lower during the female tournament compared to that of the males; however, no statistically significant differences were found regarding the injury burden between the tournaments. the overall number of self-reported injuries was considerably high, which suggests that future research should also investigate injuries not resulting in time-loss. this may suggest that the large amount of self-reported injuries was insignificant as they do not result in time-loss; however, it does indicate that players experience musculoskeletal complaints during participation, which may affect performance and is a threat to player safety.[11] sub-clinical trauma or repetitive microtrauma could be one explanation for this and should be explored in future research. few studies in field hockey have explored the prevalence of overuse injuries. overuse is reported at 28.7% of all injuries in female high school field hockey, and at 17% of all injuries in female collegiate field hockey.[10] in male and female club hockey, it is reported that chronic/overuse injuries are 20% table 3. associations with tournament injuries factor sub-category not injured during tournament injured during tournament statistical and p-value previously injured in past year no 92 47 x 2 = 20.645 p < 0.0001 odds ratio (95% ci) = 3.548 (2.034 – 6.190) risk ratio (95% ci) = 1.861 (1.375 – 2.519) yes 32 58 gender female 56 53 x2 = 073 p = 0.390 male 69 52 original research 5 sajsm vol. 33 no. 1 2021 more frequently reported than acute injuries. [10, 12] in a german study comparing indoor and outdoor field hockey, outdoor hockey reported overuse for males and females as a combined 53.4% of all reported injuries.[4] this supports the theory that the burden of overuse injuries is often greater than observed and which may account for the incidence/time-loss mismatch seen in the present study. generalisability of the study results the present study may be used as an updated record of observational injury incidence for south african field hockey, which should be improved upon over time. the injury definition used in this study, ’any physical discomfort resulting from hockey related activity, regardless of severity or need for medical attention,’ was broad enough to capture all physical complaints and to subsequently categorise them by time-loss and whether medical attention was required. this is in line with the consensus statement for football injuries, which the researchers deemed to be a sport similar to hockey in physical and tactical game play.[8] the format of the tournaments in the present study included seven consecutive days of fixtures for all participating teams, regardless of playoffs and finals. this is not common practice in international field hockey, with tournaments such as the summer olympics and world cup taking place over several weeks. it is thus hypothesised that the format of the tournament had an influence on observed injuries for both males and females in field hockey. this has been explored in other team sports, including cricket, rugby, and football. in football, it has been reported that congested periods of fixtures can affect the match recovery of players.[14] this may present challenges when comparing injury rates with other tournaments or seasonal field hockey research. despite the heterogeneity of definitions, methodologies, and formats in research, the researchers maintain that the results of this study are an estimate of all injuries observed in the tournament format of field hockey for senior participants within south africa. strengths and limitations the present study included the largest sample observed in south african field hockey to date and combined both male and female participants. it is the first study in south africa to capture male injury incidence in field hockey. the injury incidence observed in the present study should form part of long-term injury prevention for south african field hockey participants. this is in line with the sequence of injury prevention proposed in 1992 [15], which has since been updated to include the ‘translating research into prevention practice’ framework, and the ‘team sport injury prevention’ cycle [16]. through each evolution of the injury prevention paradigm, injury surveillance remains the foundation on which prevention or risk reduction is built. the definition of injury utilised in the present study is both a strength and a limitation. it allowed the researchers to capture all injuries experienced by participants because of its all-encompassing definition, which is a strength. much of the current literature captures only injuries causing time-loss or removal from field of play as their identification of injury.[1] the use of time-loss in the identification of injury would have yielded a limited amount of data compared to what was collected with this study’s definition. the use of self-reporting allowed the study to explore a large sample, albeit with limited resources. this method, combined with the broad injury definition, allowed the study to observe injury and its association through a wide lens. in the current context of this research being the first of its kind in south africa, an overview was warranted so that subsequent research can further explore the main findings of this study. the use of a self-reporting questionnaire as the method of injury reporting is a limitation to the present study.[17] the subjectivity of self-reported injuries can lead to overor underreporting of injuries, and although participants were guided by the injury definition, there remained a constant potential input error. the completion rate of the injury questionnaire was also a limitation to this study, and during both tournaments, responses declined throughout the week. this limited the ability of the data collected to reflect the actual injury incidence of the players during the tournaments, as it assumed that the non-responses represented non-injury. this poses a challenge for future research to create a follow-up protocol or to use thirdparty data collection to mitigate the decline in the response rate as a tournament progresses. the short observation period (seven-day tournament), combined with the study’s inclusive injury definition and selfreporting design, may have led to overreporting of the incidence of injury compared to that in existing literature. furthermore, this may have led to the underestimation of the role of overuse injuries being part of the high incidence rate recorded. although it was postulated that certain injuries not resulting in time-loss would fit into an acute-on-chronic pattern or be caused by previous injury or overuse, the researcher cannot objectively comment on this based on the limitations in the classification of injuries. the study was also unable to categorise injury mechanisms, and it is unknown whether contact or non-contact mechanisms caused the injuries observed. the use of injury classification systems, such as the oslo sports trauma research questionnaire [18] or the orchard classification system, [19] could have strengthened the external validity of the study. recommendations for future research the researchers recommend the exploration of web-based surveillance for future research.[3] this method is already employed by national bodies for cricket and rugby within south africa [17] and would allow saha to observe patterns of injury over extended periods of time in different formats of the game. internationally, a clear consensus statement for field hockey research should be issued by the fih to standardise future research. [4, 9, 10, 12, 20] conclusion to our knowledge, this was the largest observational study conducted in south african field hockey that included both original research sajsm vol. 33 no. 1 2021 6 male and female players. high incidence rates of all injuries and medical attention injuries were identified; however, the incidence of time-loss injuries was low in comparison to existing literature. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors appreciate the time of the research participants, provincial unions, and the south african hockey association. author contributions: np was the primary researcher. lc and tlb supervised the research and were involved in the design and review processes of this study. all authors read and approved the final manuscript. references 1. theilen t-m, mueller-eising w, wefers bettink pj, et al. injury data of major international field hockey tournaments. br j sports med 2016;50(11):657-660. 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[doi: 10.1016/j.jsams.2006.02.009] [pmid: 16616614] 17. brutus s, aguinis h, wassmer u. self-reported limitations and future directions in scholarly reports analysis and recommendations. j manage 2013;39(1):48-75. [doi: 10.1177/0149206312455245] 18. clarsen b, rønsen o, myklebust g, et al. the oslo sports trauma research center questionnaire on health problems: a new approach to prospective monitoring of illness and injury in elite athletes. br j sports med 2014;48(9):754-760. [doi: 10.1136/bjsports-2012-092087] [pmid: 23429267] 19. rae k, orchard j. the orchard sports injury classification system (osics) version 10. clin j sport med 2007;17(3):201-204. [doi: 10.1097/jsm.0b013e318059b536] [pmid: 17513912] 20. barboza sd, nauta j, van der pols mj, et al. injuries in dutch elite field hockey players: a prospective cohort study. scand j med sci sports 2018;28(6):1708-1714. [doi: 10.1111/sms.13065] [pmid: 29377400] j o u r n a m o f t h e s a s p o r t s m e d i c i n e a s s o c i a t i o n si4dicts miedicinie pqfrtgienieieskundie t y d s ® if v a n di e s a s p o r t g e n ee s k un d e v er e n i gi n g / : a • physiotherapy backweek • back injuries • ultra man •soccer injuries v o l 2 n o 3 1987 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) reg. n o ./h r.tv 5 .1/233 [53 ] in sports injury and trauma. didopm«jc mdium sc 99 r«9 ke x/1k2s3 v o lt a re n g t 50 g e ig y didophenac sodium 50 mg (enteric coated tablets) for full p re s c rib in g in fo rm a tio n c o n s u lt mdr o r p a c k a g e in s e r t o r c ib a -g e ig y ( o i l ) 9 2 9 9 1 1 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a contents journal of the s.a. a sports medicine tydskrif van dies a sportgeneeskundeverenioino w m editorial comment teaching of sports medicine kb feature back week d feature back injuries in gymnastics w m pensees sport and the philosophy of life w t j ultra man ultra man put to test e71 sasma news f£] feature soccer injuries [ 3 abstracts bodybuilders' psychosis fe1 feature memory jogger fe1 forum rugby injuries and tackle national symposium editor inchief drcnoble mb bch, fcs(sa) associate editors proftnoakesmbchb.md dr daw ie van velden mb chb (stell), m prax med(pretoria) advisory board medicine: dr i cohen mb chb d obst, rcoc orthopaedic traumatology: dr p firer bsc (eng) mb bch (wits) m med (orthoxwits) bric e hugo mb chb, mmed (chir) orthopaedics dr jc usdin mb bch, frcs (edin) cardiology: col dp myburch sm mb chb, facc physical education: hannes botha d phil (phys ed) gynaecology: dr jack adno mb bch (wits) md (med) dip o&g (wits) front coven transparency courtesy of image bank. the journal o fth e s a sports medicine association is exclusively sponsored by ciba geigy (pty) ltd. the journal is produced by bates hickman and associates (pty) ltd., po box 783776, sandton 2146. the views expressed in this publication are those of the authors and not necessarily those of the sponsors or publishers. august 1987 vol 2, no 3,1987s p o rtb e s e rin g s en s p o rt in ju ry a n d k a rd io re ha b*)ftasie | c a rd ia c r e h a b ilita tio n p ro g ra m p ro g ra m m e 16 c ib a -g e ig y 1r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) teaching of sports medicine clive noble mbchb.fcs (sa) editor in chief n recent months i have been touring south afri­ ca giving lectures on sports injuries. unfor­ tunately, i have often been appalled at the lack of knowledge of general practitioners as regards sports injuries and sports medicine in general. there are a few enthusiastic souls who have a positive interest but for the re­ mainder of the doctors, the interest has been sadly lacking. the teaching of sports medicine in our universities has been kept to a minimum. there is no university, to my knowledge, that has a course in sports medicine or even a course in sports injuries, despite the fact that in private practice, a consider­ able number of injuries are seen. in many cases the sports injured patient and especially the runner, will seek al­ ternative medicine rather than attend a general practitioner as they feel that the knowledge of the gp. is not suffi­ ciently good and therefore the assess­ ment and handling of the injury has left the runner frustrated and because of the usual advice of 'rest for six weeks' untreated. surely the time has come for our medical schools to in­ troduce a course, albeit short, in sports medicine, taking in the various fields. many sporting injuries are not specific to sport but particularly the overuse in­ juries are seen almost exclusively in sport. bio-mechanics, as a subject, is almost excluded from university curric ulae i do not think that it should be the task of sports medicine doctors to be teaching cps basic sports medicine up­ dating of knowledge should be all that is required. in this journal we have a stimulating article on soccer injuries written under supervision by two medical students. why cant there be more like this com­ ing from our universities? let us hope that the future will see an emergence of sport medicine from our halls of learning. comrades marathon some time ago i queried what would happen if there were a large number of casualities in comrades. i also sug­ gested that the qualifying time be reduced to reduce the numbers in the race in the media it was reported that more than adequate facilities existed to cope with all emergencies and that there was no need to reduce the quali­ fying times. well, this year the com­ rades organisers were put to the test. the sight of runners lying on stretch­ ers on the ground did not give one the impression of "adequate facilities". i am told that the medics did a sterling job, however, under trying circumstances. the excessive heat was obviously a major factor in creating the problems. in the us.a. many races would be can­ celled with the temperatures ex­ perienced during comrades. i do not daily news know the answer because cancelling comrades would have resulted in a riot the likes of which would have made the worst soccer violence pall into insigni­ ficance. possibly the doctors involved in comra­ des treatment should have the power to take obviously ill or injured runners off the road. back injuries back injuries in sport cover the whole spectrum of severity from the "nigg ly" to the catastrophic. they often make diagnosis difficult and treatment even more so. the catastrophic injuries, i.e„ injuries causing paralysis are fortunately rare in controlled sporting situations diving into empty swimming pools and shal­ low streams with resulting neck injury and quadriplegia can only be prevent­ ed by public education. neck injuries on the sports fields are largely associated with the high tackle in rugby and the collapsed scrum. both of these are in the process of being eliminated with the high tackle being outlawed and ex­ perimental changes to the scrumming laws occurring. some sports place tremendous loading forces on the spine with resultant in­ jury. gymnastics, squash and wrestling are such sports. here rule changes will not result in a diminution of these in­ juries so from the medical point of view one has to be sure that the com­ petitors have maximum musculo­ skeletal fitness in order to try and reduce injury possibilities. another problem facing sports doctors is the aging sportsman whose discs are already degenerating. here even more carefully controlled exercises may be necessary in order to prevent injury. the old adage for example still applies one must be fit to play squash and not play squash to get fit!. we wish the physiotherapists the best of luck in their national back week in september 1987. august 1987 vol 2, no 3,19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) back week hysiotherapy back week 1 6 september 1987. backache is one of the most common ailments seen by doctors and phy­ siotherapists it has been estimated that 80% of people suffer from significant backache at least once in their lives backache affects people's lives in all spheres and is a drain on the country's economy (see statistics) four years ago, the south african society of physiotherapy (sasp) deci­ ded that it was time to start educat­ ing the public on how to prevent and handle backache. national physiother­ apy back week (npbw) thus became an annual event in september during npbw, exhibitions at shopping centres educate the public not only on backache, but on the skill of physio­ therapists in dealing with the problem. physiotherapists have long ceased to function as "technicians" and are now ranked as full professionals in the term. a four year b sc course is now the standard qualification for physiothera­ pists many physiotherapists then pro­ ceed to specialist in the treatment of spinal problems. sponsors have assisted the sasp in producing posters, pamphlets and a nigh quality video on backache (ciba geigyj), all used during np back week. the sabc, & satv has also given cover­ age as well as many newspapers and magazines throughout the country. feedback from the public has been ex­ cellent. there appears to be a great nunger for knowledge about backs. e educational skills of the physio­ therapists are, generally perhaps, not appreciated by medical practitioners wno could prescribe it as readily as ui* t prescribe anti-inflammatories, tnout adequate education, no back airjnn1: can seated effectively, sur yicany or conservatively. ^ u s t 1987 vol 2, no 3,1987 the sasp have not limited themselves to npbw only in their new venture: on­ going projects have been initiated and are worked on throughout the year, eg. the problem of undesirable exercises being given to schoolchildren. mem­ bers of the sasp are going out and educating the schools constantly, help­ ing to modify these exercises and teach children to re­ spect their spi nes, from the beginning. schools also been given puppet shows and been involved in art and po­ ster compe­ titions. the official sasp npbw poster is in fact based on the winning entry from the pretoria school for music art ballet & drama the art departments of up and the pretoria technicons were also involved in de­ veloping a logo for the sasp npbw is an ambitious project with far reaching ideals the sasp are to be con­ gratulated on being the ones to tackle it and deserve the success it enjoys. gillian oosthuizen curriculum vitae dip physio uofs private practice, specialising in spinal re­ habilitation. read papers on the subject at three international congresses. lec­ tures ballet students at the pretoria technicon and pretoria school for mus­ ic, art, ballet & drama on body condi­ tioning and injuries. has been a consul­ tant for various fitness organisations over the last five years. closely involved with npbw statistics o f back pain onanygivendayintheusa,6.5millionmen and women are in bed with low back trouble backinjuriesarethe major indus­ trial disabler. 600 000 workers are away from their jo b s during each year because they hurt theirbacksatwork. according to one estimate this costs their employers about a billion dollars annually in sick pay and in wages for replacement personnel. am ong chronic conditions that limit the activities o f americans at home and at work, bad back rates third—afterarthritis/ rheumatism and heart trouble the reduction o f 40.8% in man hours lost through education and the running o f back schools has been found tobe the best way to handle back trouble. in the uk in 1979, back pain cost british industry 18millionlostworkingdayscom pared with 9.3 from strikes. it cost 18 000 millionrand inlost productionandcostthe state 180 million rand. insouth africa thestatisticsare very hard to come by. from sanlam insurance com ­ pany one statistic is 59% o f the claims in 1983in the age g ro u p o fl5 —24 years were from back and neck problems in the male and 70% in the female r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) feat ur, back injuries in gymnastics he stress placed by gymt nasties on the muscu­ loskeletal system is well known, and disorders about the upper extrem­ ity especially of the shoulder and of the lower extremity particularly the knee certainly occur with great frequency. another area of special concern in the young gymnast, however, is injury to the back and spine in the course of training and competing in this sport. the demands placed on the back, the lower back in particular, for both dra­ matic range of motion and a high lev­ el of strength in performing maneu­ vers and in absorbing shock of dis­ mounts may well exceed that of any sport. in association with such demands, the incidence of disorders of the spine in gymnasts appears to be high.2!j this potential for back injury appears to result not only from single episodes of macrotrauma but also from the repea­ ted microtrauma of hyperflexion, hy­ perextension, or twisting while per­ forming gymnastic maneuvers. jackson et al. first noted an apparent increased incidence of spondylolysis in young female gymnasts when com­ pared with a control population.5 they hypothesized that this was due to the repeated hyperextension of the spine occurring in gymnastics. snook reported two cases of spondylolysis among 66 major injuries in compe­ titive female gymnasts.9 more recently, a report by dzilba and cervin suggested that high level competitive gymnasts appear to have a disturbingly high incidence of problems inclu­ ding not only spondylolysis but also frank vertebral apophyseal compres­ sion fractures and mechanical back pain.2 they re­ viewed the case histories of five elite lyle j. micheli, m .d. ders of the intervertebral discs. figure 1. a and b: a young gymnast is shown in a zero degree of lordosis, anterior-opening boston brace for spondylolysis. figure 2. the hyperextension test, done with each leg, can be diag­ nostic of spondylolysis if pain is elicited with the maneuver. spondylolysis spondylolysis is certainly of of greatest concern as a cause of low back pain in the gymnast. these athletes will usually pre esent with complaints plaints of low back pain, although this is sometimes asso­ ciated with radiat­ ing pain into one or both buttocks this pain is often first noted when the gymnast does a back flip or back walk-over and is often insidious in onset. oc­ casionally, the gymnast indict a single epi­ sode of hyperextension, ora fall, as initiating the pain. although initially only elicited with gymnas ic maneuvers, the pain often be­ comes progres­ sively more sev­ ere with activities of daily living, to the point where it may interfere with simply sitting in school or sleeping. it is, however, usually relieved by supine po­ sitioning. examination examination often reaugust1987 vol 2, no 5, 193*! gymnasts with back evidence of radiographic de­ generative changes on all of their radio­ graphs. although the increased in­ cidence of spon­ dylolysis in gym­ nasts has received most attention, we have found that back pain in the gymnast may be due to a variety of causes, rang­ ing from simple hyperlordotic back pain through ver­ tebral body frac­ tures and disorpain and noted r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) veais a child with a hyperlordotic posture forward bending is often pain­ less but rising to an upright position, particularly against resistance may elicit pain. even more specific, having the child stand on one leg then the other while hyperextending the back will often elicit pain. in the case of the unilateral pars fracture, pain while hyperextending the back and standing on the ipsilateral leg may prove to be diagnostic (fig 2). neurologic examination of the lower extremities is usually unremarkable although there is often some "relative" tightness of the hamstrings it is impor­ tant to emphasize the term "relative," since straight leg raising to 90 degrees from the supine position, while consi­ dered well with­ in the range of normal, may re­ flect a loss of 30 or 40 degrees of motion in a pre­ viously hyper flexible gym ­ nast. careful questioning will usually reveal whether the athlete feels that he or she has lost flexibili­ ty, since flexibili­ ty of the back and hamstrings is a carefully monitored qual­ ity in the gymnast. plain radio­ graphs of the lumbar spine, in­ cluding an­ teroposterior, lateral, and both oblique views are obtained to assess the in­ tegrity of the posterior ele­ ments both ob­ lique views must be obtained, since only a sin­ gle pars interar ticularis may be f r a c t u r e d . although a grade i spondy­ lolisthesis may be evident on the lateral radiograph, particularly if a standing view is obtaining, it is ex­ tremely rare to encounter a higher qrade slip in these patients if the plain radiographs are interpreted as being normal but a high index of suspicion jor spondylolysis persists, based on the nistory and clinical findings, a 1®cnnetium-99 radionuclear bone scan of the lumbar spine should be ob­ tained (fig 4). we have had several pa­ tients with initially "normal" plain radi­ ographs who, on subsequent evalua­ tion, showed clear-cut evidence of pars defects on additional radiographs. if this study shows increased uptake of radionucleotide, we treat the child for a presumptive diagnosis of spondylo­ lysis. unfortunately, not even a normal plain radiograph and a negative bone scan will absolutely rule out spondylolysis as a cause of low back pain. in addition, the presence of an active bone scan should not be used as an absolute criterion for whether to institute treat­ ment in a child with spondylolysis. we have had a number of cases of children with low back pain, suggestive plain radiographs, and "normal" bone scans who have gone on to demonstrate fur­ ther symptoms and, in one case, to progress to a first degree slip. figure 1. a and b, a young gymnast is shown in a zero degree of lordosis, anterior-opening boston brace for spondylolysis. management the management of symptomatic spondylolysis in the young gymnast re­ mains controversial. some physicians are content to manage the patient symptomatically with limitation of ac­ tivity, including no further gymnastics. occasionally, a soft elastic garment, or corset, and flexion exercises are added to the regimen. it is my opinion that this lesion should be treated as a fracture of the pars in terarticularis albeit a stress fracture, the result of repetitive microtrauma and every attempt should be made to reduce the fracture and protect the spine in order to maximize the potential for healing. for this purpose we have used a rigid polypropy­ lene lum ­ bosacral brace which is con­ structed with 0 degrees of lum­ bar flexion, in an attempt to flat­ ten the low back and increase the chance for heal­ ing by opposing the fractured pars elements (fig. 1). once satisfacto­ ry fitting of the brace is at­ tained, the child wears the brace 23 hours per day, with one hour out of the brace for bath­ ing and exer­ cises, which in­ clude abdominal strengthening, pelvic tilts, and antilordotic and lower extremity flexibility exer­ cises. brace treatment lasts for six months or until the bone scan, if i n i t i a l l y positive, becomes negative. most children become asymptomatic within three weeks after brace treat­ ment is initiated, and we allow activi­ ties thereafter, including sports activi­ ties, so long as the child remains asymptomatic. for the gymnast, limit­ ed bar work and tumbling are possible but vaulting and most balance beam ^•cust1987 vol 2, no 3,1987 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) work are not possible. the results of brace treatment are promising. our most recent review of the results of bracing in symptomatic spondylolysis demonstrated that 32 per cent of patients attained bony healing with this program and that 88 per cent of the 75 patients became pain free and were able to resume pain free sports activity even if bony heal­ ing could not be demonstrated by plain radiographs.8 it is important to em­ phasize that athletically incurred spon­ dylolysis is a stable lesion. we have not encountered a significant slip in any of our patients, despite continued activi­ ty. we therefore believe that the child and parents may be counseled that this lesion does not result in spinal in­ stability but, rather, in potentially activity-limiting back pain in the young athlete or adult. as such, every effort should be made to heal the lesion. however, if a lesion does not heal but remains asymptomatic, we believe that the child may still safely participate in vigorous sports activities. although the presence of a positive bone scan at the site of fracture is in­ dicative that the body is still trying to heal the lesion, and may reflect an en­ hanced potential for healing, the presence of a cold bone scan in a radi­ ographic lesion should not be taken as a contraindication to brace treatment. we have attained bony healing in five patients with initially cold bone scans. although we are pleased that 88 per cent of our spondylolysis patients treated with braces became asympto­ matic and resumed full sports activi­ ties, we are still experimenting with new brace designs and different treat­ ment regimens. we are attempting to increase the healing rate above 32 per cent, since frank bony healing of the lesion must hold a better long-term prognosis. vertebral body fracture another cause of back pain in the young gymnast is fracture of the ver­ tebral end plates, particularly at their anterior margins. these fractures ap­ pear to be usually the result of repeti­ tive microtrauma most probably repeated flexion which injures the an­ terior portions of the end plates and can result in frank vertebral wedging. in the gymnast, these fractures usual­ ly occur at the thoracolumbar junction and may involve three or more ver­ tebral bodies, although one or two lev­ els of involvement are more common. at times, these lesions may be labeled scheurmann's disease, or "atypical scheurmann's disease.''" classic scheur­ mann's disease, as characterized by sorenson, occurs in the thoracic spine and involves at least three or more ver­ tebral bodies, with greater than 10 per cent wedging of each body.10 true scheurmann's disease, of course, may also be the result, at least in part, of repeated flexion microtrauma of the dorsal spine in a child who has tight lumbar lordosis, with forward flexion occurring in the dorsal spine rather than in the lumbar spine below. once again, plain radiographs are usual­ ly sufficient to make the diagnosis of this microtraumatic fracture. a bone scan generally shows increased uptake at the lesions but is not necessary for diagnosis. treatment is directed toward putting the spine at rest in order to facilitate normal bony healing. if signifi­ cant vertebral body deformation has already occurred, additional steps should be taken to unload the front of the spine and maximize the potential for bony reconstitution. in our opinion, this is best accomplished with a semi­ rigid thermoplastic brace. if the lesion is at the thoracolumbar junction, a brace with 15 degress of built-in lordo­ sis is used to immobilize the back and unload the front of the spine. brace treatment is used, once again, for 23 hours per day and is continued until bony healing and vertebral body recon­ stitution are evident usually four to six months.7 these children usually become asymp­ tomatic in three or four weeks, and, again, limited gymnastic training is al­ lowed as long as they remain asymp­ tomatic. as with spondylolysis, a high index of suspicion when the athlete first complains of back pain and early initiation of treatment will maximize results. discogenic back pain the differential diagnosis of back pain in the young gymnast must include dis­ cogenic back pain. this disease in the prepubescent child is rare, but its inci­ dence in the adolescent, particularly in the athletically active adolescent, ap­ pears to be increasing.6 the presentation of this disease in the young athlete may be quite different than that usually encountered in the adult. back pain, as such, may be a rela­ tively minor complaint. more frequent­ ly, the child, or his or her coach, may notice a loss of hamstring flexibility, sometimes unilateral, or the onset of a sciatic scoliosis. diagnosis may be difficult to make physical examination may reveal evi­ dence of sciatic irritation, with positive straight leg raising or a positive la segue's sign. loss of reflexes or frank muscle weakness is unusual. often, however, there will be a loss of the abil­ ity to forward flex the spine or reverse the lumbar spine on forward flexion, and this movement may elicit pain. as with all disc disease, conservative treatment aimed at resting the back in a neutral position and avoiding fur­ ther pain or muscle spasm is the primary mode of treatment. in our ex­ perience, the adolescent with disc dis­ ease will usually respond rapidly to bed rest with decreased pain and muscle spasm, but this response may not last if activities are resumed too early we will generally advise the family that their child will be out of vigorous i sports activities for 6 to 12 months fol­ lowing a frank episode of discogenic continued on p c 15. august 1987 vol 2, no 3,190 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sport and the philosophy of ufe dr dp van velden head: deft of family medicine, faculty of medicine, university of stellenbosch. t seems only logical that a sports medicine journal should explore the philo­ sophy of sport and exer­ cise, looking to the very reason why modern man enjoys the experience of human movement. it would be difficult to understand why almost compulsive devotion to some of the simplest forms of physical activity should create such an exhilarating feeling if consider­ ation were not given to the holistic na­ ture of man uniting his body and soul and mind in an equilibrium of earthly bound, transcendental existence. if we are to persue a complicated philosophi­ cal explanation for the basic phenome­ non of sport, we will fail to come to a clear understanding of what human movement is all about. we must rather become like chil . ~ _ _ . . dren again, recog­ nizing the very truth in our exis­ tence, and revel­ ling in the mere gift of life, admit­ ting that we par­ ticipate in mean­ ingful activities simply for the fun of it! we need to be liberated for so many artificial barriers in our lives if we do not want to fall victim to stress, alcohol and drug abuse, addiction to calo­ ries and nicotine and a host of hy­ pokinetic diseas­ es it is amazing to come to the reali" s ' l h zation that many ____ __ of the meaning' x . ful activities we e * 8 'n could be explained in very r n n i? t e r m s a r e w e n o t all striving to ina happiness in the search of what reaiiy matters the truth makes life worthwhile? it is in this constant search for meaning through exercise that we are able to lose some of the unneces­ sary burdens western society has im­ posed on us. these burdens have blur­ red our vision so much that we are un­ able to see that happiness and fulfil­ ment are actually within us and cannot be bestowed on us by materialistic means. love cannot be bought, traded or begged it has got to be created un­ conditionally through devotion to our conception of the truth. if sport and exercise bring us closer to this ideal, we do not need to look any further for ex­ planations of why people enjoy sport in the same way as children enjoy their play. dit is nie 'n vreemde verskynsel dat sportgeneeskundiges hulle soms besig hou met filoso fiese soeke na die redes waarom sport en oefening so 'n belangrike hoeksteen vorm van 'n gesonde leefwyse nie. ge bore uit die wete dat die mens 'n g e in t e g r e e r d e wese is waarin lig gaam, siel en gees in ekwilibrium ver keer, is dit duidelik dat aantasting van enige van die drie komponente van die menslike bestaan aanlei ding kan gee tot versteuring van die gesondheid. dit is deur hierdie holistiese siening dat geneeshere al hoe meer onder die indruk gekom het dat gesond­ heid meer is as net die afwesigheid van siekte of gebreke, en dat insette van ons maatskaplike en sosiale sisteem, die ekologie en geestelike verryking net so august 1987 vol 2, no 3,1987 'n belangrike aspek van gesondheid uitmaak as 'n gesonde liggaam. indien reg aangewend, kan sport en oefening 'n sterk bondgenoot word op die pad na gesondheid. sou die posi tiewe motiveringseienskappe van fiks heid ten opsigte van gesonde eet-, rooken drinkgewoontes te wyte wees aan die feit dat betekenisvolle fisieke aktiwiteite 'n optimale geestelike en sielkundige klimaat skep waarin 'n ge­ sonde lewenspatroon gedy? dit blyk egter nie altyd so simplisties te wees nie! alleenlik wanneer oefening en sport as 'n genotvolle aktiwiteit of spel uitbundige vreugde verskaf, ontdek die mens homself en die doel van sy aard se bestaan binne die konteks van die sin in die lewe. dit is jammer dat so baie mense oefening as 'n marteling ervaar en met geen oorredingsvermoe oortuig kan word dat dit wel 'n bron van plesier kan wees nie. dit mag wees dat die moderne kompeterende lewe die genot uit die spel gehaal het deur 'n oordrewe wen-motief en prestasie moraal in sport te bring. dit het 'n gemeenskap van "verloorders" gekweek om te verloor bly 'n negatiewe motiveringsfaktor indien die deel nemer nie daarin kan slaag om sy benadering ten opsigte van oefening aan te pas tot 'n genotvolle geestelike ervaring deur 'n fisieke medium nie. daarom is dit belangrik dat ons weer sal besin oor die doel en wese van sport en oefening. indien die strewe na fiksheid gesondheidsbevorderend moet wees, is dit nodig dat die kinder like vreugde van toegewyde deelname aan sinvolle aktiwiteite weer deel sal vorm van ons lewe die mens soek gedurig na ingewikkelde oplossings vir sy probleme, terwyl die antwoord dikwels so eenvoudig kan wees ontdek jouself, jou behoeftes en gebreke, maar ook jou potensiaal deur sport en oefening! deur te konsentreer op die singewende aspekte van sport en oe­ fening, kom ons nader aan die ervar ingswereld van die kind wat nog uit bundig kan lag vir die spel van die lewe? r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r7 thewraps "i are off! s m i t h + n e p h e w healing m m x r hands smith and nephew ltd., 30 gillitts road. pinetown 3610 22̂ how elastoplast porous elastic adhesive bandage gives controlled compression and flexible support w h e n treatm ent dem ands a bandage that gives compression and flexible support, your first choice must . be elastoplast porous elastic adhesive bandage. the secret of the effectiveness o f elastoplast porous elastic adhesive bandage lies in its exceptional lengthways stretch and regain properties which enable it to be applied with the correct tension to give controlled compression. these same stretch and regain properties give flexible support allow ing patient m obility and full participation in rehabilitation programmes. d eveloped for south a frican conditions, elastoplast porous elastic adhesive bandage is ideal for strapping swollen or sprained joints, varicous veins, leg ulcers and for other surgical and orthopaedic purposes. the soft fluffy edges of the bandage help to avoid cutting and m arking the skin. a n d although adhesive, the bandage is porous, allow ing the skin to breathe and sweat and exudate to escape. it is features like these, coupled, with back-up service and strapping technique training program m es that have made elastoplast porous elastic a dhesive bandage your first choice for the past 50 years. n ow the wraps are off, ask for it by name when you need controlled compression and support. ’ regimcrctl trade mark r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r "ultra man put to test' multi-disciplinary endur­ ance event such as the ele­ ments which go to make up the ciba-ceigy sponso­ red ultra man, makes special demands, even on the ultra fit athlete the institute of sport research and training at the university of pretoria is paying special attention to the physio dynamics of the various events invol­ ved. problems could, for instance arise in an athlete who has successfully com­ pleted the comrades marathon on many occasions, when he is challenged to turn his hand, or rather his muscles, to a different ultra distance discipline such as cycling or canoeing. under the guidance of hans daehne, the sports institute puts athletes through their paces, quite literally, un­ der controlled laboratory conditions. leading athletes such as iron man ed­ die king, and transvaal flyhalf schalk naude, subjected themselves to the in­ stitute's battery of tests. these include anthropometric tests, i.e. body type measurements such as mass / height, fat weight ratios and muscle measurements. by specialising in one ultra distance dis­ cipline, muscles are selectively deve­ loped and strengthened. eddie king with his dominant emphasis on run­ ning and cycling was unable to reach his ankles due to shortening of the hamstrings, whereas schalk naude could place his hands flat on the floor. the cybex test measures muscle strength and endurance. under strict conditions of measurement, both the extension and flexion of a limb joint is measured through its total range of motion. while the athlete delivers his maximum output, the cybex compu­ ter plots the appropriate curve. if any svstem is damaged, the injury wn show up as a deviation on the cy tracing. in this way the precise lo­ cation and severity of injuries can be oemonstrated and appropriate physio nerapy or corrective exercise routines prescribed. the institute emphasises the impor­ tance of style in any sport, but particularly in running. top notch cyclists and canoe­ ists tend to have an awkward running style, and it is in the running events that the most injuries during the ultra man sequence are expected. the institute can however get canoeists of on the right foot, so to speak. leaflets are avail­ able on running style — the importance of stance, follow through with the ball of the foot and good arm move­ ment. during the demo peri­ od even eddie king by making a minor adjustment to style was able to smooth his perfor­ mance. a computerised spirometer is used to measure lung func­ tion and lung capacity. wired up like an astronaut, the athlete performs against set standards while instruments measure his capacity to trans­ port oxygen through heart and lungs and convert it into energy at muscle level. this complex parameter, the v02 max, a measure of the body's ability to accept and utilise oxygen is also an index of performance on the athlete's path to superfitness. schalk naude demonstrating the spirometer test v o o b n e n /w and trauma. didophenac sodium 50 mg ( entericcoated tablets ) ^ g ho. k/5.1/253 (wet/act 101/1965) s 3 c ib o -g e ig y (pty) ltd p.o. b ox 9 2 isan do 1 6 0 0 f o r full prescribing informotion please refer to the m.d.r. * ucwt1987 vol 2, no 3,1987 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) u ltraman will test the best with entries having closed for the johannes­ burg stock exchange marathon, the first op­ tional event within the ultra man competition, i think it ap­ propriate to reflect developments wi­ thin ultra man to date response to the competition has been nothing short of phenomenal if one considers the rather substantial chal­ lenge that entrants are faced with. at the time of going to press 132 en­ trance applications had been received and if the encouragingly numerous queries that are received on a daily ba­ sis are anything to go by, a similar num­ ber of entries yet again can be anticipated. there are an abundance of top competitors who have taken up the challenge including the likes of dr "tiffy" king, graeme pope-ellis and george janos, with unconfirmed rumours having it that danny bigg's en­ try is in the pipeline. it seems unlikely that as a former gold medalist in the iron man, hansa duzi and comrades, danny will turn down the opportunity to earn a potential r18000 from a competition that seems tailor made for him. whatever his decision, the na­ ture of the ultra man is such that it would be most difficult to speculate who the winner might be. the tactical element that competitors are faced with in terms of choosing events is bound to add a decisively interesting dimension to the challenge, with a bet­ ter than average competitor who com­ pletes all eight events standing a good chance of being up there with the best of them. a misconception that has developed amongst interested parties is that ultra man will have their final points stand­ ing calculated on an average rather than on an aggregate basis. the oppo­ site is in fact the case which means that any event completed will yield a positive addition of points to a compe­ titors total. a maximum of 100 points will be earned by the first ultra man home in each event which means that a total of 800 points could be earned in the unlikely event of one athlete win­ ning all eight races. for those people who have not yet en­ tered, i would like to stress that entries will be welcomed up to november 15. the first compulsory event is the vas byt ultra man cycle challenge on november 28, a 165km cycling event which is dominated by a series of rather daunting hills. entrants for ultra man will be mailed information on this event which will include a map of the route. with the "vasbyt" looming i would like to take this opportunity to wish our competitors the best of luck in this event, the second out of the eight en­ durance tests that lie ahead. bester takes ultra man lead comrades marathon specialist nick bestertakes 100 ultra man bonus points into the 165km vasbyt cycle ultra mara­ thon on november 28 after finishing ninth in the recent 50km johannesburg stock exchange marathon. thejsewasthefirstoptionaleventona gruelling ultra manfixture list and bester who was 25th in the comrades mara­ thon this yearin 6:12:08, finished ninth af terthe run from johannesburg to voor trekkerhoogte with a time of 2:59:07. as the top ultra man finisher, bester fromlefttorightcraemepope-ellis, danny biggs, dr eddie king, nic bester, piet mare. earned an automatic 100 bonus points. points were awarded to the other ultra man contenders according to a special formula and piet mare grabbed second place on the log with 92,38 points after clocking 3:12:54 in the jse. third is top endurance athlete danny biggs, who is having a "full go" at ultra man after a disappointing comrades mara­ thon thisyearin which hefinishedoutof the gold medals in 18th place. biggs picked up 85,99 points for his 3:24:28in the jse,justahead of duzi "king" graeme pope-ellis. “the pope" clocked 3:25:51 for 85.22 bonus points, while pierre de jager is fifth on the ultra man log with 84,72 points from a time of 3:26:45. phillip van tonder is sixth (84,02 points; jse time of 3:28:01), followed by roger zipp (83,13; 3:29:38); phillip demosthe nous(82,72; 3:30:22), veteran geoff mat­ thews (81,77; 3:32:06)and kenneth poole (81,71; 3:32:12). leading the woman in the series spon­ sored by ciba-geigy is experienced ultra­ distance athlete priscilla carlisle, who earned 68,76 pointsfrom her jsetimeof 3:55:37. sally luckoff has 59,37 from 4:12:44 and . sandra niemand 45,45 from 4:37:47 a total of 164 ultra man competitors ran the jseinsearch of bonuspoints. among them was two-time leppin iron man tri­ athlon champion eddie king — 17th on the log with 80,02 points from time of 3:35:15. the total number of ultra man entrants so far is275,andentrieswill be accepted until october 30. missingfromthejsewascurrentsunday times/leppin iron man champion henk watermeyer. he will, however, be one of the top con­ tenders in the vasbyt ultra marathon and he still has the opportunity to boost his points tally in the midmar mile swim in february, arguscycletourin march and two oceans marathon in april. organised by spekecyclingclub,thevas byt ride starts (6am) and finishes at the continued on pa ce 19. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasha update, sasgv nuus sasma news dr. d p van velden head: department o f family medicine e a afloop van die sukses volle sportgeneeskunde kongres in kaapstad, kyk die sportgeneeskunde vereniging weer indring end na sy doelstellings om te bepaal tot watter mate die vereniging daarin geslaag het om sekere ideale te verwesenlik. alhoe wel daar heelwat verrig is met betrek king tot die bevordering en dissemina sie van kennis insake die hantering van top sportlui, publikasies van sportwe tenskaplike navorsing en die diagnose, behandeling en rehabilitasie van sport beserings, kan daar nog heelwat meer gedoen word in die veld van die kor rekte gebruik van sport en oefening vir die voorkoming van siektes en die be­ vordering van gesondheid. weens die paradoks wat daar bestaan tussen sport en gesondheid as gevolg van die negatiewe aspekte van kompe terende sport en oefening soos bv. die veelvuldige beserings, hittesteek, ver minderde weerstand teen virusinfek sies, onoordeelkundige gebruik van sti mulante ea. middels, en ook die wan opvatting wat daar bestaan dat fiks heid sinomiem is met gesondheid, is dit logies dat die mediese professie met reg skepties staan teenoor die rol wat sport kan speel in gesondheidsbevor dering. die geneesheer is primer ver antwoordelik vir sy pasient die beseer de sportman se gesondheid en kom dikwels in konflik met sportadministra teurs, afrigters en die sportman se eie belange en moet soms moeilike beslui te neem wat groot implikasies kan in nou vir 'n sportman se toekoms, soos nou ook duidelik blyk uit die geval van naas botha en die probleem van sy konkussie. alhoewel die sportman dus nie altyd die toonbeeld van gesondheid is nie, moet geneeshere kennis dra van die oaie positiewe rol wat sport en oefe­ ning mag speel in die holistiese bena qenng tot gesondheid. oonentoesiastiese sportlui self verklaar onomwonde dat hulle nie 'n dokter no o p het nie, "ek is my eie dokter ek kan me onthou wanneer laas ek siek was nie, die dokters weet nie waarvan hul­ le praat wanneer dit by gesondheid en fiksheid kom nie" ons moet ongelukkig erken dat sportlui soms geregtig is om sulke stellings te maak, aangesien ge­ neeshere dikwels geen opleiding kry in gesondheid en vele ander aspekte ra kende sportgeneeskunde nie. in hierdie opsig het die s a sportgeneeskunde vereniging 'n groot taak om geneeshe­ re toe te rus met die nodige kennis en tegnieke om sportlui bevredigend te hanteer. die tyd het waarskynlik ook aangebreek om 'n formele nagraadse sportgeneeskundige kwalifikasie in te stel om te voorsien in die toenemen de behoefte aan deskundige kennis op die gebied van die mediese aspekte van sport. the south african sports medicine association has recognized its respon­ sibility in this regard, and decided to change the format of the journal slightly, to accommodate more scien­ tific articles on health promotion through a healthy lifestyle. exercise, sport and fitness are only small, albeit important integral parts of promoting optimal health. because the medical profession has a holistic approach to­ wards health and health promotion, and realizes that the human being is highly adaptable and complicated, we have good reason to be reserved in ma­ king certain unqualified statements on health and disease prevention some­ times to the point of dissatisfaction of the general public and the sports fra­ ternity. although research done by the medical profession does not supply all the answers, we are in possession of certain sound scientific proof that a healthy lifestyle can do more than cer­ tain of the modern therapeutical mo­ dalities to preserve optimum health these are the facts that we would like to publish in our journal. the general practitioner should play a much more active part in health pro­ motion and disease prevention, as he has done in the past in his traditional palliative role as comforter of the sick fsieketrooster") in certain of the self in­ flicted chronic degenerative diseases of the western society. it has long been recognized that the super specialist cannot cater for the total needs of the sportsman, because sports medicine is a multiprofessional discipline incorpo­ rating aspects of all the traditional me­ dical specialities as well as additional knowledge of the exercise sciences, nu­ trition, psychology and even sports ad­ ministration. the sports physician should be knowledgeable of all these aspects ranging from sleep disturban­ ce in sportsmen, through drug abuse, malaria prophylaxis and the adverse in­ fluence of the ecology on the practi­ sing sportsman. the journal wishes to broaden its readership and address the family physician on all the relevant is­ sues of sport, health and the family that is necessary to promote the health not only of the individual, but also of the community as a whole. in the next few issues we envisage pub­ lishing articles on recreational sports, such as hiking for the entire family, ef­ fective stress management program­ mes in an abnormal society as well as the role of a healthy family and sexual life in the concept of holistic health. we also wish to inform our readers on forthcoming congresses and seminars in sports medicine and health matters both here and abroad. the contribu­ tion of physiotherapy to the manage­ ment of sports injuries is becoming in­ creasingly important, and it would be appropriate to have a regular column on sports physiotherapy. nutrition is also an area of major concern that can feature very prominently in our jour­ nal. the editorial committee would wel­ come any contribution from our read­ ers. it is very important that we should maintain a high standard of scientific credibility in all our articles to further the interest of sports medicine in all spheres of the health professions. ^*jcust1987 vol 2, n o 3,1987 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) soccer injuries i. surve 4th year medical student j. ranchod 4th year medical student a.n. kettles registrar from: the department o f community health, university o f cape town, s ummary soccer is the most wide­ ly played sport in south africa yet no study of soccer injuries in this country has apparently been published. this survey examines the relationship of injuries to factors, both intrinsic and extrinsic to the player all injuries are classified according to type, site, seve­ rity, recurrence, and manner of sustain­ ing the injury. a relationship between injury and some of these factors is shown, the most important being field condition, protective equipment and division played in. suggestions are made as to how to reduce these inju­ ries. it is also recommended that a fol­ low up study be done on some of the relationships emerging from this study. 1. introduction soccer is the most widely played sport in the world.1 more than 40 million ac­ tive players were registered with the federation of international football association in 1982.2 as in other con­ tact sports, soccer has an inherent injury risk w and soccer is considered to be responsible for 50-60% of all sports injuries in europe. epidemiological studies have been performed on soccer injuries 1 but it appears that no such information is yet available on south african soccer, despite the fact that soccer surpassed rugby as the most popular sport in this country in 1984.6 as an initial step towards the prevention of soccer inju­ ries in south africa, the principal authors determined the distribution and pattern of soccer injuries among amateur soccer players, over a period of 9 weeks, extending midway into the 1985 playing season. 2. materials and methods for the purposes of this survey, an in­ jury was defined as one that required the attention of the first-aid staff avail­ able at each match. the following procedure was adopted to identify injuries occurring in matches included in the survey: on the morning of each match — saturday, the first aid teams allocated to each match were given a detailed explana­ tion of the project and the question­ naire, which also had an explanatory sheet attached. specific instructions were given to ensure that a question­ naire was completed for each player who received first aid attention during the match. the two allocated first aid­ ers were accompanied by an occupa­ tional therapist or the authors until such time as they were competent to complete the questionnaire on their own. they were then checked at regu­ lar intervals to ensure that a high stan­ dard was maintained. the question­ naires were collected after each match. the questionnaire included data about factors both intrinsic and extrinsic to the players, e.g. age, division, playing position, field, weather condition, injury (type), protective equipment worn by august 1987 vol 2, no 3,19# players, referee, etc. each field was graded according to the following criteria: surface, evenness, presence of tufts and holes, clarity of markings. the survey population consisted of senior members of the cape district football association — an amateur football body with 22 clubs and a to­ tal membership of ± 10 0 0 players. senior players were defined as all play­ ers in the under 18, under 21, 2 nd, 1st and premier divisions. to assess the opinion of players about factors potentially leading to soccer in­ juries, a random sample of 100 players was chosen, using random number ta­ bles each player was asked to com plete a questionnaire listing eight possible factors from which they were asked to indicate the three which they consi­ dered were the most important. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 3 results number and incidence rate of injuries a total of 227 games were played by 6 4 teams of 11 players each while game duration varied with division. the total number of playing hours studied was 5 826. a total of 73 injuries were recorded, giving an overall injury inci­ dence of 1 injury per 80 playing hours, or 12,5 per 1 000 hours played. this reflects an average risk of 1 in 68 per game for each player. showed the highest injury incidence per game played i.e. 0,8, while the aver­ age for all divisions was 0,32 injuries per game. injury by playing position table ii shows the relationship between playing position and number of injuries the majority of injuries occurred to midfield players (32%) and the least to goalkeepers (15%). however, there is only one goalkeeper per team, and on average three backs, three forward and table i: injury distribution over divisions and time. no. of no. of no of no. of injuries total man hours incidence rate per 1000 man hours division teams games injuries per game played played u18 14 38 14 0,37 836 16,67 u21 10 40 19 0,48 880 21,74 2nd 22 95 5 0,05 2438 2,23 1st 9 24 11 0,46 792 13,89 premier 9 30 24 0,80 880 27,0 total 64 227 73 0.32 5826 12,53 different injuries with regard to divi­ sion or playing position, although lacer­ ations were relatively more common in defence positions and sprains more in attacking positions. table ii: injury incidence in different playing positions number corrected of percentage position injuries of injuries goalkeeper 11 (15%) 37,0% back 19 (26%) 21,3% midfield 23 (32%) 19,3% forward 20 (27%) 22,4% 73 (100%) 100% table ill: distribution of type of injury type of injury number of injuries sprains lacerations strains contusions fracture 31 (42%) 23 (32%) 13 (18%) 5 (7%) 1 (1% ) 73 (100%) site of injury table iv: distribution of injuries over anatomical sites number of site injuries ankle 18 (25%) thigh 12 (16%) shin 9 (12%) hand 8 (11%) knee 5 (7%) groin 4 (6%) back 4 (6%) foot 3 (4%) calves 3 (4%) elbow 2 (3%) face 2 (3%) neck 1 (1%) shoulder 1 (1%) ribs 1 (1%) 73 (100%) lower limb injuries accounted for 74% of all the injuries (54 out of 73), of which the ankle accounted for a total of 18 (25%). the upper limb injuries comprised 15% of the total (11 out of 73), with the hand accounting for 8 of these severity of injury about one in three of the injured play­ ers had to leave the field whilst the re­ mainder were able to play on. in the to­ tal of 227 games played, 23 injuries could be considered severe, defined as when a player was forced to leave the field as a result of injury. this gives an incidence rate of 1 severe injury per 10 games played, or a severe injury incidence of 4 per 1000 player hours. the overall number of injuries during each week of the season was not great­ ly different and varied from 6 to 10 per four midfield players. thus, if the data are corrected accordingly, the inci­ dence of injury is greatest for the l i f e w-ek, of which 90% were new injuries and 10 % recurrences. [ne proportion of injuries as distribut nrr?ver ĥe divisi°ns showed that they most in the p^m ier league “ 7 }•'followed by the "under 21" (26%) niimk 18’’ category (19%). the t h « u ° f p la y in 9 h o u r s "a t r is k " f o r iese three divisions were approxi e9 y3 ̂although the number of « mes differed. the premier division ^ )0ust 1987 vol 2, no 3,1987 goalkeepers. types of injury table iii shows the frequency of each type of injury. while there was only one fracture, 75% of the injuries comprise sprains (42,5%) and lacerations (31,5%), while 58% of sprains occurred to the ankle, 19% to the knee and 13% to the hand. there was no significant differ­ ence in the relative proportion of r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) field conditions all fields on which matches were played were graded according to a checklist with a maximum score of 40. the num­ ber of injuries and of playing hours for each field was determined, and the in­ jury incidence per 1000 hours was cal­ culated. when and how injuries occurred most injuries occurred in the second half (47, or 64%). the commonest method of injury was a foul (42, or 57%) of which 30 occurred in the se­ cond half. when one combines fouls and fair tackles (53) the majority (40, or 76%) occurred in the second half "the high num ber o f sprains in the forward and m idfield positions could be due to the skilful dribbling involved in these positions, especially since 16 o f the 22 sprains recorded were ankle sprains." influence of individual preparation it was established that 39% of injured players had warmed up before games and practices, and 90% had attended at least two soccer practices per week. in general 90% of injured players con­ sidered themselves fit or very fit. the injured players were virtually equally divided over those wearing screw-in studs (37 or 51%) or multi-studs (36 or 4 9 %) and no relationship could be found between the type of studs worn and the injuries sustained. shin guards were worn by 47% of players and none of these players suffered shin lacera­ tions. of the injured players, 47 (64%) participated competitively in another sport. to b e continued in the following edition august 1987 vol 2, no 3,1r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) continued fro m page 6 back pain with sciatica. as with spondylolysis and vertebral apophyseal fractures, we have found brace treatment useful in managing these adolescent athletes with disc dis­ ease. we present this treatment pro gram to the patient and parents as a way of resting the back while allowing the patient to continue being ambula­ tor/ and active, as well as continuing in school. with the patient who has disc disease, the brace that has been best tolerated, particularly early in the treat­ ment regimen, has been the somewhat softer and more flexible polyethylene brace with 15 degrees of lordosis built into the brace. as might be expected, the success rate for disc disease with the brace and rest program has not been as high as that for spondylolysis or vertebral end plate fractures. in our initial series, only ap­ proximately 50 per cent of the young athletes with discogemc low back pain were able to return to full sports activi­ ties without pain.7 it would appear wise, if at all possible, to avoid discectomy in the adolescent with disc disease although the natur­ al history of adolescents after discec­ tomy has not been well studied, the re­ cent review by de orio and bianco sug­ gested that there was a relatively high incidence of continuing back com­ plaints in these patients as adults.1 the recent increased interest in chymopapain injections for discogen ic low back pain with sciatica may have a particularly useful application in the adolescent or young adult with disco genic back pain. in such patients, of course, the disc rupture appears to be the primary event and is usually not as­ sociated with degenerative changes in the facet joints or posterior elements. thus, chymopapain injection to mechanically decompress the bulging disc and the associated nerve irritation might well allow adaptive changes to occur in the associated elements of the spine. the long-term result may be a significantly lower incidence of subse­ quent degenerative changes and back pain in this population. of course, the child with progressive neurologic symptoms, bladder and bowel complaints, or serious motor loss is a candidate for surgical decompres­ sion, as in the adult. spondylogenic back pain when the gymnast with back pain has been carefully evaluated and the afore­ mentioned diagnoses of spondylolysis, apophyseal fracture, or disc disease have been ruled out, the presumptive bgpnosis of spondylogenic back pain may be made this is usually associat­ ed with a hyperlordotic posturing of the lumbar spine, tight hip flexors, and, equently, relatively tight hamstrings and lumbodorsal fascia. children with spondylogenic back pain in association with sports activities will usually respond to a well supervised ex­ ercise program of abdominal stren ghtening, lumbodorsal and hamstring stretching, and antilordotic posturing of the lumbar spine. the pelvic tilt per­ formed in both the supine and stand­ ing position is the foundation of this exercise program. surprisingly, a survey of gymnasts in the boston area by dr michael goldberg revealed that a num­ ber of these were relatively lacking in abdominal strength.5 in some cases, exercises alone have not been sufficient to reverse the lordotic posturing of the low back and relieve the back pain. in such cases, a 0-degree, anterior opening plastic brace has proved to be very useful to relieve the child's pain and allow restoration of function/ these children usually be­ came asymptomatic in three to four weeks. bracing is usually continued for three to four months in combination with the exercise program outlined earlier, then the use of the brace is tapered. "young gymnasts com plaining o f back pain m ust never be passed o ff as having sustained a back strain o r "muscle spasms" and treated symptomatically." tumor and infection a final, extremely important consider­ ation must always be remembered in the young gymnast complaining of low back pain, even pain that is apparent­ ly associated with traumatic athletic ac­ tivities. tumors of the axial skeleton and infectious processes of the disc or end plates must always be considered in the differential diagnosis of the young athlete with low back pain. the incidence of osteogenic sarcoma of the axial skeleton is low in any age group, of course, but the adolescent and young adult are particularly suscepti­ ble to this disease process. in addition, discitis, although more common in the somewhat younger child or young adolescent, can also be encountered in the older adolescent involved in sports activities a recent case of ours outlines this point very clearly. this was the case of a 17-year-old elite tennis player who began complaining of back pain and radiation of pain into the buttocks this pain was severe enough to warrant hospital admission and evaluation. a presumptive diagnosis of discogenic back pain with severe sciatica was then obtained. however, further evaluation showed elevation of the sedimentation rate and a positive bone scan at the l1-l2 level. subsequent radiographs confirmed progressive narrowing of the l1-l2 level, and the diagnosis of disc space infection was made. the patient responded well to a program of rest, brace immobilization, and antibiotic treatment and did not require decom­ pression of the disc. summary the complaint of low back pain in the adolescent must never be taken light­ ly. a high index of suspicion should be particularly entertained in a child par­ ticipating in gymnastic training or com­ petition. as noted in this article, steps can now be taken, particularly if a specific diagnosis is made early, to in­ stitute specific treatment with a high likelihood of success. young gymnasts complaining of back pain must never be passed off as having sustained a back strain or "muscle spasms" and treated symptomatically. persistent back pain beyond two weeks warrants, in our opinion, a complete evaluation, careful history and physical examina­ tion, a four-view radiographic assess­ ment of the spine, and, if necessary, bone scans or other more advanced techniques to make a specific diagno­ sis of the cause of the pain. references 1. de orio, j. k. and bianco, aj.: lumbar disc exci­ sion in children and adolescents. j. bone joint surg. 64a:991-995, 1982 2. dzilba, r.b. and cervin, a.i.: irreversible spinal deform ity in olympic gymnasts annual meeting. american orthopaedic society for sports medicine, anaheim, california, march 1983. 3. goldberg, m.a.: gymnastic injuries. orthop. clin. north am, 11:717-724, 1980. 4. hensinger, r.n.. back pain and vertebral changes simulating scheurmann's disease orthop trans, 6:1, 1982. 5 jackson, d.w, vviltse, ll, and cirincione, r.l spon­ dylolysis in the female gymnast. clin. orthop, 117:68-73, 1976. 6. micheli, l j : low back pain in the adolescent differential diagnosis. am. j. sports med., 7:362-364, 1979. 7. micheli. l j, hall, j.f, and miller, m.e.. use o f the modified boston brace for back injuries in athletes. am. j sports med.. 8:351-356. 1980. 8. micheli. l. j, and steiner, e. m.: the use o f a modi­ fied boston brace to treat symptomatic spondylol­ ysis orthop. trans, 7:20, 1983. 9. snook. ga: injuries in women's gymnastics. am. j. sports med, 7:242-244, 1979. 10. sorenson, h.k.: scheurmann's juvenile kyphosis. copenhagen, munksgaard, 1974. division of sports medicine children's hospital medical centre 300 longwood avenue boston, massachusetts 02115 \ a i august1987 vol 2, no 3,1987 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) bodybuilders' psychosis urther warning of the f hazards of misuse of ana­ bolic steroids by athletes is given by drs harrison pope and david katz of mclean hospital and har­ vard medical school in massachusetts. they treated two men requiring hospital admission for psy­ chosis apparently related to steroid use one was a 22-year-old construction worker who took two eight-week courses of methandrostenolone for bodybuilding. the second was a 40-year-old man with idiopathic impotence who developed major depression with delusions and hallucinations after being prescribed "after the second course he developed severe depressive sym ptom s which lifted after several m onths b u t were followed by prom inent paranoid and religious delusions." methyltestosterone for two weeks. neither patient had any serious psy­ chopathology before this episode and no medical or neuroendocrine abnor­ malities were found. both responded well to neuroleptics and have remained psychiatrically normal for more than two years follow up with no further steroid exposure. intrigued by these cases, drs pope and katz interviewed 31 other anabolic steroid users recruited through adver­ tisements in gymnasia: three had psy­ chotic symptoms including hallucina­ tions and delusions and at least four others had 'subthreshold' psychosis in­ cluding paranoid jealousy and gran­ diose beliefs. in addition, four met criteria for manic episodes while taking steroids and five had major depres sion.none of the subjects described comparable behaviour when not using steroids. such cases show that in ad­ dition to well-described medical effects of anabolic steroids there may be seri­ ous psychiatric effects which have so far been largely unexplored. lancet, 1987, apr 11, i,863. acknowledgement medical news tribune jun 25, 1987 george d. rovere, md low back pain in seasoned athletes is not common, but when present it can limit participation. while direct blows or hyperlordotic positions can cause low back pain in certain sports, the most common cause is overuse and resultant strains or sprains of the paravertebral muscles and ligaments such injuries cause acute pain and spasm, which sometimes do not ap­ pear for 24 hours or longer. diagnosis is based on history, ruling out of sys­ temic maladies, physical examination, and, if necessary, supplemental tests such as x-rays, myelograms, and bone scans. treatment of low back pain due to overuse is, sequentially, bed rest and ice for 24 to 36 hours, heat and mas­ sage, analgesics as needed, and a lum­ bosacral support until flexion and strengthening exercises have returned the damaged part to normal. reference the physician and sportsmedicme vol 15, no. 1, january 87 august 1987 vol 2, no 3,1! 16r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) b omrades torture track by carolyn mccibbon research on runners could provide a new way of boosting performances in the comra­ des marathon by reducing body tempe­ rature and cutting out some of the gruelling agony of the 87-km race. the research — which is a world first — is still in its infancy, and critics have cal­ led for more comprehensive tests and controls before the results are accep­ ted. but early tests show that cramps, nausea vomiting, diarrhoea and kidney problems — which make the durban to pieterm aritzburg route a torture track — are linked to poisons, called endotoxins, relea­ sed into the blood­ stream from the gut after strenuous exercise tests carried out in the medical tent at last years comra­ des, showed that more than 80 per­ cent of runners in the survey had very high endotoxin levels antibodies fight the endotoxins, and research from natal medical school shows that hard training is a natural way of increasing the antibodies but runners eager for boosted perfor­ mances may be tempted to inject themselves with antibodies manufactured by the blood bank. this could cause ethical problems for comrades' organisers who are battling to keep the sport clean. runners are al­ ready subject to tests by the sa ama )?!dr athletics union, but it would be difficult to prove whether runners are injecting themselves with antibodies. mrdanie malan, chairman of the saaau medical committee, said no road runner yad been tested positively for drugs, and “blood doping" was unknown in south africa. professor john brock-utne of the phy ^ o g v department at natal university, wno headed the endotoxin research said: "we have shown that high l n” jpx'ns can cause nausea, vomiting «nd diarrhoea. this may be circumven" when a runner is exhausted, he needs m ore blood sent to his muscles and so the bloodsupplyis shunted from the gut. as a result, the barrier that stops endotoxins from entering the blood is broken down and the endotoxins com e stream ing o u t." ted by high levels of antibodies and one way of getting these high levels is through training" "it appears that with high antibodies you are protected from all the bad side effects of high endotoxins people with high antibodies may be able to perform better; he said. he explained: "when a runner is ex­ hausted, he needs more blood sent to his muscles and so the blood supply is shunted from the gut. as a result, the barrier that stops endotoxins from entering the blood is broken down and the endotoxins come streaming outr endotoxins interfered with the normal functioning of the circulatory system, he said, which then affected the heart, muscles and kidneys. oxygen in the blood was reduced and body temperature shot up, making the runner more tired. poor circulation led to cramps and kidney problems, he said. the basic treatment for kidney failure — which killed one comrades marathon runner last year — was to give intrave­ nous fluids, which would have the effect of flushing endotoxins out of the sys­ tem, he said. professor brock-utne suggested that in the future runners could be tested if they were unsure whether they would be able to complete the course their antibody levels could give an indication of how fit they were people with very low antibodies might then be advised not to run, he said. comrades doctor john godlonton said he had strong reservations about draw­ ing conclusions from the research, be­ cause there were no controls, and the sample was only drawn from runners who had collapsed in the medical tent. dr bosie bosenberg from natal univer­ sity's anaesthetics department, who was part of the endotoxin research team, said it was still too early to draw significant implications from this study. "the results indicate a correlation be­ tween high endotoxin levels and nausea, vomiting and diarrhoea but because we had a very small sample of athletes, it is difficult to draw conclusions" the results could be biased, he said because only 89 runners in bad shape had been assessed. acknowledgement sunday tribune 31 may 87 ‘̂ 'i-'ust1987 v° l 2, no 3,1987 17r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) featurea memory jogger exercises to prevent and treat low back pain 1 pelvic tilt. lie on your back with knees bent, feet flat on the floor, and arms at your sides tighten your stomach muscles and flat­ ten the small of your back against the floor, without pushing down with the legs. hold for five seconds, then slowly relax. 2. knee to shoulder. starting in the same position as for the pelvic tilt, grasp your right knee and gently pull it toward your right shoul­ der. return to the starting position and repeat with the left leg alternate legs 3. double knee to chest, starting in the same position as for the pelvic tilt, use your hands to pull your right leg close to your chest, and then pull the left leg even with the right. grasp both knees and pull them toward your shoulders. let the knees return to arm's length and repeat. 4. partial slt-up. do the pelvic tilt, and while holding this position, curl your head and shoul­ ders up and forward. hold briefly. return slow­ ly to the starting position 5. h a m strin g s tre tch . from the same start­ ing position as for the pelvic tilt, bring one knee to your chest and then straighten the leg vertically, stretching the heel toward the ceil­ ing. you should feel the stretch behind your knee bend the knee and return the leg to the starting position. repeat with the other leg 6. r o tatio nal slt-up. do the pelvic tilt and, while keeping your hips flat, rotate your up­ per body so that the weight rests on the left shoulder then, curl your head and shoulders upward, raising your right shoulder higher than the left hold briefly before returning to the starting position. rotate your upper body to the right and repeat the movement, this time raising the left shoulder higher than the right. 7. cat and cam el. on your hands and knees, relax your abdomen and let your back sag downward then tighten your stomach mus­ cles and arch your back repeat. 8. trunk flexio n, prone. starting on your hands and knees, tuck in your chin and arch your back upward, and then slowly sit back on your heels while letting your shoulders drop to the floor relax return to the starting po­ sition. keeping stomach tight and back arched. repeat. .......... 9. trunk flexio n, seated. sitting near the edge of a chair, spread legs apart and cross arms over your chest be sure the chair will not slip backward or tip. tuck your cnin and slowly curl your trunk downward. relax. uncurl slow­ ly into an upright position, raising your head last r eference vol 15, no. 1, january 87. the physician and sports medicine. continued from pace 10 bester takes ultra man lead lynnwood drive-in theatre and the clos­ ing date for entries is november 2, all vasbyters who complete the race within lohourswillreceiveamedal, track suit badge and certificate. thenext compulsory eventafterthecy clechallengeisthehansaduzi in january, in which ultra man entrants can paddle either single or k2 canoes. the other compulsory events are the 160km sunday times/leppin iron man triathlon in february and the87km com­ rades marathon next june. the overall winner will receiveagold me­ dal and r10,000, with a medal and r1.000 for the others in the top 10 and r2.000 and a medal forthewinnerof each com­ pulsory event. in addition, there will be a medal and r1.000 for the first master(over40)and a medal and r2.000 for the top woman. for further information contact michelle reimers at sports inter­ national on (011) 883-3333. ultraman results for jse marathon1 s t 20 pos. name total points 1. nicolaas bester 100.00 2. piet mare 92.38 5. danny biggs 85.99 i 4. graeme pope-ellis 85.22 1 5. pierre dejager 84.72 6. phillip van tonder 84.02 7. rogerzipp 83.13 8. philip demosthenous 82.72 9. geoffmatthews 81.77 1 10. kenneth poole 81.77 11. stephen rehbock 81.15 12. norrie willliamson 81.14 1 13. didierentressangle 8090 14. lochilochner 80.82 15. richard marshall 80.13 16. jako vanheerden 80.09 17. eddie king 80.02 18. roelofdu toit 79.88 19. martin wood 79.13 20. colin cooper 78.70 1 women's results 1. pricilla carlisle 68.76 2. sallyluckhoff 59.30 3. sandra niemandt 48.22 1 august 1987 vol 2. n0 3.1s 18r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ” forum i rugby injuries and tackle people, have it pushed through earlier, even on a local experimental basis. yours faithfully dr s ger ps. the playing time should be divided into 4 sessions with 3 min breaks be­ tween each session. reply to dr ger's letter the rugby injury refering to dr selwyn ger's letter regarding rugby injuries, it remains en­ couraging to note that some physicians forum for our readers this forum invites our readers to air their views on any subject related to sport and sports medicine. we welcome your ideas, criticisms, con­ tribution, etc address correspondence to: the managing editor, commedica, po box 3909, randburg 2125. the editor sports journal rugby injuries and tackle dear sir with regard to the above i wish to state, that the incidence can be reduced, pos­ sibly to 0,5% by1) proper coaching techniques with emphasis on basics — how to fall, how to tackle, how to scrum etc. 2) change the tackle law a) for schools — a tackler may only aim for the body area, be­ tween the shoulder (under the axilla) and the hips (on or above circumference bounded by sym­ physis pubis, anterior and posteri­ or superior iliac spines) b) the tackle will not involve throw­ ing the ball carrier to ground. the ball carrier will only have to be held in this position and he must then release, pass or kick the ball. in other words — it would be a modi­ fied form of touch rugby. if, however the ball carrier is thrown to ground, it will not be against the rules. by changing the tackle law as above, i reel that (even for senior rugby) it will: 1j speed up the game 2) it will cut down on rucks, mauls, pile ups — thereby reducing injuries. 3) reduce injuries in general and es pecially knee and ankle injuries. i nave written a similar letter to dr c an'e craven who mentioned that such changes may take ages via the in­ ternational rugby board, out, why shouldn't we, as medical sports august ig 87 v0l nq—igg7 remain concerned about rugby injuries and are willing to make suggestions regarding possible ways of reducing these injuries. it is important that dr ger forwards detailed proposals to the medical com­ mittee of the s.a. rugby board. possi­ ble law changes will also involve discus­ sions with the particular governing bodies like the sa. schools rugby as­ sociation in this case before a well moti­ vated proposal can be presented to the s.a. rugby board for fu rth e r consideration. all attempts must be made to in­ troduce law changes without changing the basic spirit and the game itself. dr hugo chairman: medical committee rugby board sports injury reprint service sports injuries occur as a result of phys­ ical activities carried out either for general recreational purposes or with more professional goals in mind. they may be caused by accidents or by over­ use, and they do not necessarily differ from injuries sustained in non-sporting activities. most sports injuries are minor and would not prevent the average athlete from continuing his daily work, but as more and more people become seri­ ously committed to sporting activities continuing daily work is no longer the only consideration. the injury needs to be treated effectively so that leisure activity can also be resumed at the earliest opportunity. progress in diagnosis and treatment is making rapid strides in the field of sports medicine, and to keep doctors abreast of recent developments ciba geigy have introduced a sports inju­ ry reprint service. this service searches medical publications for the most recent articles dealing with sports medicine and makes them avail­ able to interested doctors. careful and planned rehabilitation is es­ sential after an injury. ciba-geigy, as leaders in the field of antirheumatic and sports medicine, awarded a grant to the national sports research and training institute to promote scientif­ ic sport research and training. doctors who wish to receive reprints of articles dealing with sports medicine on a regular basis, ond/or would like more information on the ciba-geigy sport injury rehabilitation programme should write to: ciba-geigy (pty) limited pharmaceutical division po box 92 isando ^ 1600 19r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) national symposium i heme: drugs & sport par‘jc|pa‘ on da‘ e to be ad w h j h | vised venue: sp o rts h mbm centre — un versitv of pretoria as a result of the negative publicity concerning sport participation and the use of drugs as well as the ignorance and health dangers of the incorrect use of illegal drugs, the institute for sport research and training at the universi­ ty of pretoria have decided to hold a national symposium in order to de­ velop sound perspective in this regard. experts in this field have been invited to present papers covering various top­ ical issues regarding this subject. the programme is as follows: the techniques of testing — by dr p vd. merwe (uovs) medical aspects of ergogenics & other chemical compounds — by dr d. v. vel den (university of stellenbosch) biochemistry of illegal drugs — by professor f. terblanche (university of zululand) ethical aspects — by professor hannes botha (university of pretoria) the use of anabolic steroids from a health point of view — by professor r. van rooyen (university of pretoria) scientific-accepted training methods for the development of strength — by dr n de bruyn (university of pretoria) diet and strength development — by ms mieke faber (national medical coun­ cil — tygerberg hospital) invitations will be sent out to coaches, physiologists, parents, general praction ers and members of the pharmaceu­ tical industry. for further information please contact cert potgieter or petra talijaard at tel. no (012) 342-2150. c m e course in sports medicine — durban 1987 the sa. sports medical association is organising a continued sports medical educational course in durban from the 7th to 9th of april 1988. this will be held in the elangeni hotel. emphasis will be placed in various medical and physiological aspects in the runner and include training and conditioning as well as methods of treating running injuries. forms of intent will be sent to all members of the s.a. sports medical association and other interested bodies. further information will be published in sports medicine journal vol 2 no 4 in november. however early registra­ tions and queries can be directed to organising committee sasma hatfield forum west 2nd floor 1067 arcadia street hatfield pretoria 0083 tel no. 012 43-5594/5/6 in memoriam it is with great regret that we learned of the passing away of dr etricia prins loo in july this year, just five months after having diagnosed her own illness — a rare form of leukaemia. etricia was a medical doctor working on a master's degree in sports medicine (biokinetics) at the university of pretor­ ia. she was the secretary of sasma since april 1987 and an active member of the association since its inception four years ago she played a major role in improving communication and co-operation be­ tween physiotherapists and medical practitioners involved in sports medi­ cine and has been actively involved in the expansion of sports medicine in south africa. she will be sorely missed by all sasma members and we would like to take this opportunity to extend our sincere sym­ pathy to her husband and family. the: suid-afrikaanse sport geneeskunde vereniging south african sports m edicine association application form aansoekvorm full member/volle lid r25 student member/studente-lid r5 tel no/tel n r ............... masa no/mvsa nr . f u ll m e m b e r ; m e a ic a i p ra c iih o n e r rs w h o a re m e m b e rs o f m a s a v o ile l id : m e d ie s e p r a k iis y h s w a ile d e v a n d ie m v s a is s t u d e n t m e m b e r : m e d ic a l s iu d e m s in c lin ic a l y e a^s s t u d e n t e l e d e : m e d ie s e s tu d e n te in huf k iin te s e ja re a p p lic a tio n s lo r m e m b e r s h ip o l s. a s m a s h o u ld b e s e n it o the s e c re ta ry s a s m a . h a tfie ld f o ru m w e s i 1067 a r c a d ia s ire e l h a tfie ld . p 'e io n a c 0 8 3 c h e q u e s 10 a c c o m p a n y m e m b e r s h ip fo rm august 1987 vol 2, no 3,19£ 20 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) avultion-fj1-sc1-jf-f sajsm vol 17 no. 1 2005 27 background a 24-year-old rugby player presented to an orthopaedic surgeon with a history of dislocation of the left shoulder. it reduced spontaneously and dislocated again later during the same match. on examination there was no residual instability, but the apprehension test for anterior instability was positive. speed s test as well as o brien s test for slap (superior labrum anterior to posterior tear) lesions were negative. there were no signs of rotator cuff tear or impingement. case report and diagnostic procedures the patient was sent for an x-ray series consisting of the routine impingement series and additional views of the inferior glenoid (bernageau and westpoint). no fracture of the inferior glenoid was demonstrated. a magnetic resonance imaging (mri) scan was then requested to evaluate the labro-capsular structures and to exclude an occult fracture or articular surface tear of the rotator cuff. the mri scan showed an avulsion on the inferior glenohumeral ligament attachment to the humerus (figs 1 and 2). this is described as a hagl lesion (humeral avulsion of the glenohumeral ligament).1 arthroscopy of the shoulder confirmed the diagnosis of a hagl lesion (fig. 3). an open procedure was performed to repair the lesion. the postoperative period was uncomplicated and the patient made a full recovery with full range of motion and no residual instability. discussion the hagl lesion is an uncommon cause of recurrent dislocation of the shoulder1,10,13 although biomechanical studies have found a higher percentage of hagl lesions.2 because of the anterolateral to inferolateral location, hagl lesions can be difficult to visualise during arthroscopy and a preoperative diagnosis using mr arthrography can be useful. the most common consequence of a shoulder dislocation in the young subject is a bankart lesion or a bankart variant of the anterior glenolabral complex.5-7, 10, 11 in hagl lesions there is a macroscopic tear of the capsule at the humeral attachment, also described as a reversed bankart lesion. associated injuries are common and include rotator cuff tears, hill-sachs fracture of the postero-superior humeral head, biceps tendon lesions and brachial plexus injury.3, 4, 12 case report humeral avulsion of the glenohumeral ligament of the shoulder r v p de villiers (mb chb, mmed (rad d)) 1 j f de beer (mb chb, mmed (orthop)) 2 k van rooyen (mb chb) 2 p e huijsmans (md)2 c p roberts (frcs (trauma and orthop) 2 d f du toit (d phil (oxon), phd, mb chb, fcs (sa), frcs (ed), fica (usa))3 1 dr van wageningen and partners, vergelegen and stellenbosch mediclinics 2 cape shoulder institute, cape town 3 department of anatomy, stellenbosch university, w cape correspondence: r v p de villiers po box 317 somerset west 7129 tel: 021-851 5545 fax: 021-852 2697 e-mail: rmldev@mweb.co.za fig. 1. mr arthrogram of the shoulder. coronal t1 fat-saturated study shows avulsion of the inferior glenohumeral ligament from the attachment onto the humerus (arrow). note the j-shaped configuration of the axillary recess, which is normally u-shaped. note the impaction fracture of the posterolateral humeral head (dotted arrow). avultion-fj1-sc1-jf-f 5/3/05 8:57 am page 27 28 sajsm vol 17 no. 1 2005 imaging with mr arthrography is the non-invasive investigation of choice.4, 8, 9 management is usually surgical, although conservative management is used in selective cases. references 1. bach br, warren rf, fronek j. disruption of the lateral capsule of the shoulder. a cause of recurrent dislocation. j bone joint surg br 1988;70:274-6. 2. bigliani lu, pollock rg, soslowsky lj, flatow el, pawluk rj, mow vc. tensile properties of the inferior glenohumeral ligament. j orthop res 1992;10:187-97. 3. bui-mansfield lt, taylor dc, uhorchak jm, tenuta jj. humeral avulsions of the glenohumeral ligament: imaging features and a review of the literature. am j roentgenol 2002;179:649-55. 4. coates mh, breidahl w. humeral avulsion of the anterior band of the inferior glenohumeral ligament with associated subscapularis bony avulsion in skeletally immature patients. skeletal radiol 2001;30:661-6. 5. habermeyer p, gleyze p, rickert m. evolution of lesions of the labrum-ligament complex in posttraumatic anterior shoulder instability: a prospective study. j shoulder elbow surg 1999;8:66-74. 6. hintermann b, gachter a. arthroscopic findings after shoulder dislocation. am j sports med 1995;23:545-51. 7. palmer we, caslowitz pl. anterior shoulder instability: diagnostic criteria determined from prospective analysis of 121 mr arthrograms. radiology 1995;197:819-25. 8. sanders tg, morrison wb, miller md. imaging techniques for the evaluation of glenohumeral instability. am j sports med 2000;28:414-34. 9. stoller dw. mr arthrography of the glenohumeral joint. radiol clin north am 1997;35(1):197-116. 10. taylor dc, arciero ra. pathologic changes associated with shoulder dislocations. arthroscopic and physical examination findings in first-time, traumatic anterior dislocations. am j sports med 1997;25:306-11. 11. wall ms, o brien sj. arthroscopic evaluation of the unstable shoulder. clin sports med 1995;14:817-39. 12. warner jj, beim gm. combined bankart and hagl lesion associated with anterior shoulder instability. arthroscopy 1997;13:749-52. 13. wolf em, cheng jc, dickson k. humeral avulsion of glenohumeral ligaments as a cause of anterior shoulder instability. arthroscopy 1995;11:600-7. fig. 2. mr arthrogram of the shoulder. aber (abduction external rotation) view shows a lax inferior glenohumeral ligament. fig. 3. arthroscopic view, looking from posterior through the joint at the anterior capsule. the capsule is torn off the humerus, with the fibres of the subscapularis seen deep to it. avultion-fj1-sc1-jf-f 5/3/05 8:57 am page 28 review 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license anxiety and depression in athletes assessed using the 12-item general health questionnaire (ghq-12) a systematic scoping review n armino,1,2 bsc honours; v gouttebarge,1,3,4 phd; s mellalieu,5 phd; r schlebusch,6 pgce dip; jp van wyk,6 nd sports management; s hendricks1,2,7 phd 1 division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, cape town, south africa 2 health, physical activity, lifestyle and sport (hpals) research centre, university of cape town, cape town, south africa 3 amsterdam umc, university of amsterdam, department of orthopaedic surgery, amsterdam movement sciences, meibergdreef 9, amsterdam, netherlands 4 amsterdam collaboration on health & safety in sports (achss), amsterdam umc ioc research center of excellence, amsterdam, netherlands 5 cardiff school of sport and heath sciences, cardiff metropolitan university, cardiff, united kingdom 6 south african cricketers’ association, cape town, south africa 7 institute for sport, physical activity and leisure, leeds beckett university, leeds, united kingdom corresponding author: s hendricks (sharief.hendricks01@gmail.com) poor mental health of current and retired athletes is a major concern in sport.[1–7] typically, the incidence/prevalence of mental health symptoms in athletes is studied using symptom-specific questionnaires. for symptoms of anxiety and depression (often comorbid), one such self-reporting questionnaire is the 12-item general health questionnaire (ghq-12). the ghq-12 is a popular self-reporting measure of mental health.[8] the ghq has been used in community, clinical and sport settings.[9,10] the original ghq consists of 60 items, while the shorter more popular version contains only 12 items (ghq-12).[11–13] the popularity of the ghq-12 can be attributed to its robust psychometric properties and being quick and unobtrusive to administer.[11–13] the ghq-12 includes six positively phrased items (e.g. ‘have you been able to concentrate on what you were doing’) and six negatively worded items (e.g. ‘have you lost much sleep over worry’). the ghq-12 can be scored in several ways. for the traditional ghq scoring method (0-0-1-1), items are answered on a 4-point scale with the response categories and scoring values for the positive items representing: ‘not at all’=1, ‘no more than usual’=1, ‘rather more than usual’=0, and ‘much more than usual’=0; and those for the negative items ‘not at all’=0, ‘no more than usual’=0, ‘rather more than usual’=1, and ‘much more than usual’=1.[14] the scores are summed to obtain a total score between 0-12. a score of ≥2 indicates symptoms of anxiety/depression.[9,11] goldberg also suggested that to obtain an optimal trade-off between sensitivity and specificity, the mean score of the group could be used as a threshold.[15] the less frequently used likert-type scale scoring (0-1-2-3) can also be used. the scores are summed to obtain a total score between 0-36, with higher scores indicative of lower psychological wellbeing. because of the larger scoring range compared to the traditional scoring method, the likert-type scale scoring is potentially more sensitive in detecting changes in psychological well-being over time.[11] while a number of reviews on the mental health of elite athletes are available in the literature, [2–5] no review currently exists which focuses specifically on anxiety and depression using the ghq-12. one narrative review provided an overview of the prevalence and risk factors for depression but failed to discuss the tools used to measure depression.[5] other reviews background: the poor mental health of athletes is a major concern in sport. typically, the incidence/prevalence of mental health symptoms in athletes is studied using symptom-specific questionnaires. for symptoms of depression/anxiety, one such selfreporting questionnaire is the 12-item general health questionnaire (ghq-12). objectives: the aim of this review was to synthesise and compare studies using the ghq-12 in athletes to inform future research bodies by identifying trends and gaps in the literature. methods: a systematic search of five electronic databases (google scholar, pubmed, psychinfo, scopus and web of science) was conducted on all published studies up to 1 january 2019. inclusion criteria: (1) participants were able-bodied athletes; (2) studies measured anxiety/depression using the ghq-12; (3) studies were full original articles from peer-reviewed journals; (4) studies were published in english. results: thirty-two studies were included in the review. the prevalence and incidence of symptoms of anxiety/depression ranged from 21-48% and 17-57%, respectively. the majority of studies screening anxiety/depression using the ghq-12 were cross-sectional. almost 70% of the studies used the traditional scoring method. the majority of study populations sampled allmale cohorts comprising football (soccer) players. conclusion: the traditional scoring of 0-0-1-1 should be used with the cut-off set at ≥3. also, the mean ghq-12 score should be reported. potential risk factors for symptoms of anxiety/depression (i.e. recent adverse life events, injury and illness, social support, pressure to perform and career transitioning) and a lack of prospective studies were identified. future research should also broaden the spectrum of athlete populations used and aim to improve response rates. keywords: mental health, elite athletes, sport, well-being s afr j sports med 2021;33:1-13. doi: 10.17159/2078-516x/2021/v33i1a10679 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a10679 https://orcid.org/0000-0002-0126-4177 https://orcid.org/0000-0003-2868-3328 https://orcid.org/0000-0001-8885-5940 https://orcid.org/0000-0002-3416-6266 https://orcid.org/0000-0001-8414-0139 https://orcid.org/0000-0003-2753-0194 review sajsm vol. 33 no. 1 2021 2 have a broad scope, covering many mental health symptoms and psychological well-being behaviours (e.g. sleep disorders, adhd/add, eating disorders).[2–7] this makes it difficult to compare studies to develop interventions for depression and anxiety. in response, a scoping review of the literature focusing on studies using the ghq-12 was performed. the aim of this review was to synthesise and compare studies using the ghq-12 in athletes in order to inform future research by identifying trends and gaps in the literature. methods search this review was reported in accordance with the preferred reporting items for systematic reviews and meta-analyses (prisma) guidelines. a systematic search of five electronic databases (google scholar, pubmed, psychinfo, scopus and web of science) was conducted on all published studies up to 1 january 2019. key terms included: anxiety, depression, mental health, elite athletes, athletes, sport, general health questionnaires, ghq and combinations thereof. inclusion criteria for the review were: (1) participants were able-bodied athletes; (2) studies measured anxiety/depression using the ghq-12; (3) studies were full, original articles from peerreviewed journals; (4) studies were published in english. studies were excluded if athlete and non-athlete populations were combined as a single group. athletes are defined in this review as individuals who train in sports aiming to improve their performance; are actively participating in sport competitions; registered in a local, regional or national sports federation; and devote several hours on most days to their sport. studies were screened at the title and abstract level for eligibility. if a decision on the eligibility of the study was unclear at the title and abstract level, the full text was retrieved and screened. after merging the databases and removing duplicates, a second author screened the studies for reliability purposes. a schematic of the process is shown in fig. 1. data extraction the authors, year of publication, study design, purpose of the study, study population characteristics (sample size, age, active/retired, ratio of men to women, country), ghq-12 (scoring method, cut-off point, mean score), prevalence and incidence of anxiety/depression, as well as factors associated with anxiety/depression were extracted from each study and tabulated. results a total of 202 studies were identified through database searching, while five were retrieved through other sources. after duplicates were removed, 175 studies were screened by title/abstract, of which 37 full texts were assessed. finally, 32 studies were included in the review (table 1). study design the majority of studies used either a cross-sectional (56%, n=18),[9,16–32] or a prospective design (38%, n=12).[33–44] one study used a randomised controlled trial design[45] and another used a quasi-experimental design.[46] population characteristics the majority of studies were conducted on football players (50%, n=16). other sports that have used the ghq-12 are rugby union (16%, n=5), cricket (9%, n=3), ice hockey (9%, n=3), and gaelic football (6%, n=2). only one study has been published on australian football players, distance runners, handball players, and horse jockeys, respectively. the majority of studies included all-male cohorts (69%, n=22), while only one study included an all-female cohort. several studies included mixed cohorts (22%, n=7), while a couple did not specify the sex of the participants (6%, n=2). the majority of studies included adult athletes (81%, n=26), while some used only adolescent athletes (13%, n=4). a few studies included both adult and adolescent fig. 1. schematic of the literature search according to prisma guidelines review 3 sajsm vol. 33 no. 1 2021 athletes (6%, n=2). most of the studies consisted of active athletes (63%, n=20). several studies included retired athletes exclusively (19%, n=6), while others included both active and retired athletes (19%, n=6). most of the included studies used elite athletes, where this was defined as professional, international/national or olympic-level athletes (84%, n=27). non-elite athletes in other studies included university, adolescent/high school, or local/regional athletes (16%, n=5). prevalence/incidence the prevalence of symptoms of anxiety/depression assessed by the ghq-12 ranged from 21-48%. the incidence of symptoms of anxiety/depression ranged from 17-57%. ghq scoring method and cut-off points the studies (72%, n=23) used mainly the ‘traditional’ ghq scoring method (0-0-1-1), while 19% (n=6) used the likertscale scoring method (0-1-2-3). the remaining studies (9%, n=3) did not specify the ghq scoring method. of the 23 studies that used the traditional ghq scoring method, 43% (n=10) set the cut-off at ≥two, another 43% (n=10) at ≥3 and two studies (9%) set the cut-off at ≥4. one study did not specify the cut-off point for indicating symptoms of anxiety/depression. discussion the ghq-12 is a popular tool used to screen the presence of anxiety/depression symptoms among athletes. its popularity can be attributed to its robust psychometric properties and quick unobtrusive administration.[11–13] this is the first review to focus specifically on the ghq-12 in order to compare studies and identify potential risk factors for anxiety/depression, as well as methodological considerations for future research. not surprisingly, methodological inconsistencies between studies using the ghq-12 were found. sixty-eight percent (n=23) of the studies used the traditional 0-0-1-1 scoring method. of these 23 studies, three different cut-offs were applied. for future research, we recommend the traditional scoring of 0-0-1-1 be used. furthermore, to improve anxiety/depression prevalence and incidence comparisons, we also suggest that the recommended cut-off for the ghq-12 for athletes be set at ≥3. in addition, the mean ghq-12 score should be reported, as suggested by goldberg.[15] most of the studies used a cross-sectional or prospective cohort design with the objective of determining the prevalence and incidence of symptoms of anxiety/depression. the prevalence and incidence ranged from 21-48% and 1757%, respectively.[9,16,17,19,23,25–34,36–40,42,44,46] a sample of elite athletes from the united kingdom (cricket, fencing, hockey, rugby union and many others) and elite gaelic athletes presented with the highest prevalence of anxiety/depression symptoms (48%),[9,40] while the highest incidence was found in a sample of elite dutch athletes (57%).[38] the response rates for most of these epidemiological studies were around 30%, with 40% comprising samples of european professional football players,[16,19,26,27,29–31,33,34,36,41,42] thus decreasing the generalisability of the findings and highlighting a clear area for further investigation. several studies have identified potential risk factors for anxiety/depression symptoms. the most notable of these are recent adverse life events,[17,19,27,31,44] career dissatisfaction,[9,26,44] injuries,[19,40] surgeries,[19] social support,[21,31] osteoarthritis, pressure to perform, and career transitioning.[21,23] in one study, the ghq score was used as a predictor for musculoskeletal injury.[42] although no reported association was found between anxiety/depression symptoms and severe musculoskeletal injuries, the study was novel in using the ghq score as a potential risk factor for predicting injury. using the ghq score as a predictor rather than an outcome suggests that the ghq12 could potentially be used as a monitoring tool for injury risk. two studies attempted to reduce the ghq-12 scores of athletes. wilson et al. attempted to reduce ghq-12 scores in 10 experienced jockeys using an exercise and diet intervention.[46] however, the study was limited by its small sample size and lacked a control group. the other study used a randomised control study design, where the intervention was an internetbased cognitive behavioural therapy.[45] no significant differences were found between the intervention and control group, and this was attributed to the short period of the intervention. the ghq-12 is proposed to measure symptoms of anxiety and depression (reported also as anxiety/depression).[2] although often comorbid, these are two different psychological conditions. depression is a medical condition that negatively impacts on how an individual feels, thinks and acts.[47] symptoms include sadness, apathy, guilt, low self-esteem, trouble sleeping, decreased appetite, tiredness, poor concentration and suicidal ideation.[47] depression can be chronic or recurrent, and can significantly affect an individual’s ability to cope with daily life.[48] anxiety is defined as the anticipation of a future concern, whilst fear is an emotional response to an immediate threat.[47] anxiety disorders are characterised by excessive feelings of anxiety and fear.[48] researchers and sport practitioners should be aware of the distinctions between depression and anxiety when using the ghq-12. conclusion this review compared ghq-12 studies and identified potential risk factors for depression and anxiety, as well as methodological considerations for future research. based on this review, we recommend the traditional scoring of 0-0-1-1 be used with the cut-off set at ≥3. also, the mean ghq-12 score should be reported. the prevalence and incidence of symptoms of anxiety/depression ranged from 21-48% and 17-57%, respectively. potential risk factors for anxiety/depression include recent adverse life events,[17,19,27,31,44] career dissatisfaction,[9,26,44] injuries,[19,40] surgeries,[19] social support,[21,31] osteoarthritis, pressure to perform, and career transitioning.[21,23] future research should broaden the spectrum of athlete populations and aim to improve response rates. finally, researchers and sport practitioners should acknowledge that the ghq-12 does not differentiate between symptoms of anxiety and depression. review sajsm vol. 33 no. 1 2021 4 hhhh table 1. summary of general health questionnaire (ghq) studies on athletes author study design purpose population; country n; men/ women % ghq scoring method ghq cut off point prevalence incidence predictor outcome ghq mean score findings blakelock et al., 2016[33] observational, prospective cohort psychological distress following deselection in soccer players elite adolescent footballers, 15–18 years (16.31 ± 1.10); uk 91; 100/0 ghq method 3 36% (time point 1; n=14) 55% (time point 3; n=11) at times 1, 2, 3 for released players: 2.64; 3.82; 3.36. proportion of deselected players experienced higher levels of psychological distress than retained players at postselection time points; psychological distress was reduced in retained players over time and did not change in released players at postselection time points. brown et al., 2017[25] observational, cross-sectional compare mental health between former professional rugby players who were and weren’t forced to retire retired profession al rugby union players; age (38 ± 5); age at retirement (31 ± 4); career length (8.9 ± 3.8); retirement (7.4 ± 4.4); france, ire land, south africa 293: 173 (voluntary retirement), 120 (forced retirement); 100/0 ns ns 29% (overall); 26% (retired voluntarily); 32% (forced retirement) the overall prevalence for anxiety/depression was 29%. the prevalence for forced retirement was 32%; and 26% for voluntary retirement. the prevalence between forced retirement and voluntary retirement was not significantly different. foskett et al., 2017[9] observational, cross-sectional prevalence of signs of anxiety/depres sion and distress sample of elite athletes from various individual and team sports competing at a professional, international or national level; age (24 ± 8.6); uk 143; 57/43 (1 participant did not specify gender) ghq method 2 48% career dissatisfaction *; severe injuries ghq score 48% prevalence of anxiety/depression; career dissatisfaction was a significant independent predictor of signs of anxiety/depression. gouttebarge et al., 2015a[31] observational, cross-sectional mental and psychosocial health current (mean age 27 ± 5) and former footballers (mean age 36 ± 5); duration of career: current (9 ± 5); former (12 ± 5); duration of retirement (5 ± 3); 60% play/played in the highest leagues; australia, ireland, the netherlands, new zealand, scotland and usa 253: 149 (current) and 104 (former); 100/0 ghq method 2 26% (current); 39% (retired) severe injuries; surgeries; le <12*; le >12; low social support from trainer/ supervisor; low social support from teammates/col leagues* ghq score 26% and 39% prevalence of anxiety/depression in current and former football players respectively. recent adverse life events were significantly associated with anxiety/depression in current and former footballers; low social support from teammates was also significantly associated with anxiety/depression in current footballers. review 5 sajsm vol. 33 no. 1 2021 xzxzxzxzxxcxcxz table 1 continued. summary of general health questionnaire (ghq) studies on athletes author study design purpose population; country n; men/ women % ghq scoring method ghq cut off point prevalence incidence predictor outcome ghq mean score findings gouttebarge et al., 2015b[27] observational, cross-sectional prevalence and determinants of symptoms related to mental disorders retired professional footballers; mean age 35; duration of career (12 ± 5); duration of retirement (4 ± 4); various countries 219; 100/0 ghq method 2 35% severe injuries; surgeries; le <6*; le >6; career dissatisfaction ghq score 35% prevalence of anxiety/depression. significant positive association of recent life events with anxiety/depression. gouttebarge et al., 2015c[30] observational, cross-sectional symptoms of common mental disorders in professional football professional footballers; finland, france, norway, spain, sweden 540: 121 (finland), 81 (france), 119 (norway), 70 (spain), 149 (sweden); 100/0 ghq method 2 25-43% le <6; le >6; career dissatisfaction ghq score 25-43% prevalence of anxiety/depression (spainnorway); significant correlation of life events and career dissatisfaction with anxiety/depression (finland, sweden). gouttebarge et al., 2015d[16] observational, cross-sectional severe musculoskelet al injuries and symptoms of cmd professional footballers (mean age 27; 54% playing in the highest professional leagues); finland, france, norway, spain, sweden 540; 100/0 ghq method 2 37% severe injuries; severe joint injuries; severe muscle injuries; surgeries ghq score 37% prevalence of anxiety/depression. the number of severe musculoskeletal injuries positively correlated with anxiety/depression. however, no significant associations with severe injuries/surgeries and anxiety/depression. gouttebarge et al., 2015e[26] observational, prospective cohort symptoms of common mental disorders and adverse health behaviours professional footballers (mean age 27; 55% playing in the highest professional leagues); various 607; 100/0 ghq method 2 38% severe injuries; surgeries; le <6; le >6; career dissatisfaction* ghq score prevalence of 38% for anxiety/depression. statistically significant correlations were found for severe injuries and career dissatisfaction with anxiety/depression. gouttebarge et al., 2016a[17] observational, cross-sectional prevalence and determinants of symptoms of cmd retired professional rugby union players; mean: age 38; career length 9; retirement duration 8; france, ireland and south africa 295; 100/0 ghq method 2 28% le <6*; le >6; career dissatisfaction ghq score anxiety/depression prevalence of 28%; a higher number of adverse life events was associated with anxiety/ depression. significant negative correlation with career dissatisfaction and anxiety/ depression. review sajsm vol. 33 no. 1 2021 6 dsdsdsd table 1 continued. summary of general health questionnaire (ghq) studies on athletes author study design purpose population; country n; men/ women % ghq scoring method ghq cut off point prevalence incidence predictor outcome ghq mean score findings gouttebarge et al., 2016b[34] observational, prospective cohort symptoms of cmd professional footballers (mean age 27; mean career duration of 8 years; 55% playing in the highest leagues) 384 at baseline and 262 at follow up; 100/0 ghq method 3 32% 37% adverse life events; conflict with trainer/coach; career dissatisfaction ghq score at baseline, there was a 32% prevalence of anxiety/ depression; there was a 12month incidence of 37% anxiety/depression. although not statistically significant, there was an association between adverse life events and career dissatisfaction with anxiety/depression. gouttebarge et al., 2016c[29] observational, cross-sectional relationship of level of education and employment with symptoms of common mental disorders current (mean age 27) and retired (mean age 35) professional footballers; career duration: current (7.8 ± 4.4); retired (11.6 ± 5.0); belgium, chile, finland, france, japan, norway, paraguay, peru, spain, sweden and switzerland 607 current and 219 retired; 100/0 ghq method 2 38% (current); 35% (retired) level of education; employment status; working hours ghq score anxiety/depression prevalence of 38% and 35% among current and retired football players respectively. significant negative correlations between employment status and number of hours work with anxiety /depression among retired players. gouttebarge et al., 2016d[32] observational, cross-sectional prevalence and risk indicators of symptoms of common mental disorders current (mean: age 27; career duration 8) and former (mean: age 50; career duration 11; retirement duration 20) elite athletes from various sports; the netherlands 485: 203 (current) and 282 (former); 36/64 (current); 49/51 (former) ghq method 3 45% (current); 29% (former) severe injuries; surgeries; recent adverse life events; career dissatisfaction ; support ghq score 45% and 29% prevalence of anxiety/depression among current and former athletes respectively. current and former athletes with a higher number of severe injuries, higher number of surgeries, higher number of recent adverse life events, higher level of career dissatisfaction will be more likely to report symptoms of anxiety/depression. gouttebarge et al., 2016e[40] observational, prospective cohort epidemiolo gy of cmd elite gaelic athletes (hurlers and footballers); mean: age 25; career duration 5; ireland 204 at baseline and 108 at follow up; 100/0 ghq method 3 48% 21% severe injury*; surgeries; recent life events; career dissatisfaction ghq score 48% prevalence for anxiety/depression; 6-month incidence of 21% for anxiety/ depression. significant association with severe injury and the 6-month incidence for anxiety/depression. review 7 sajsm vol. 33 no. 1 2021 dsdsds table 1 continued. summary of general health questionnaire (ghq) studies on athletes author study design purpose population; country n; men/ women % ghq scoring method ghq cut off point prevalence incidence predictor outcome ghq mean score findings gouttebarge et al., 2017a[38] observational, prospective cohort symptoms of common mental disorders elite athletes from various sports; mean age 27 years; mean career duration 8 years; the netherlands 203 at baseline and 143 at follow up; 36/64 ghq method 3 45% 57% being injured; recent adverse life events; career dissatisfaction ghq score at baseline, there was a 45% prevalence of anxiety/depression; 12-month incidence of anxiety/depression was 57%. no statistically significant associations, but career dissatisfaction did increase the likelihood of symptoms of anxiety/ depression by 3.5 times. gouttebarge et al., 2017b[39] observational, prospective cohort symptoms of common mental disorders current (mean age 26; career duration 8 years) and retired (mean age 35; career duration 11 years) professional ice hockey players 258 (135 current and 123 retired players) at baseline and 158 (81 current and 77 retired players) at follow up; 100/0 ghq method 3 24% (current); 19% (retired) 17% (current); 8% (retired) severe injuries; surgeries; recent adverse life events; career dissatisfaction; support ghq score there was a prevalence of 24% and 19% of anxiety/depression for current and retired athletes respectively. the incidence of symptoms of anxiety/ depression was 17% and 8% for current and retired athletes respectively. although not statistically significant, severe injuries, recent adverse life events and career dissatisfaction increased the likelihood of reporting symptoms of anxiety/depression in current and retired ice hockey players. gouttebarge et al., 2017c[28] observational, cross-sectional a history of concussions is associated with symptoms of common mental disorders former professional athletes (football, ice hockey and rugby union); mean: age 37; career duration 10; years retired 7; finland, france, ireland, norway, south africa, spain, sweden, switzerland 576; 100/0 ghq method 3 26% (whole group); 26% (football); 18% (ice hockey); 28% (rugby) number of concussions ghq score whole group prevalence of 26% anxiety/depression; 26%, 18% and 28% prevalence anxiety/ depression for football, ice hockey and rugby players respectively. there was a significant difference in the number of concussions when groups were divided by presence/absence of symptoms of anxiety/depression (presence having a higher number of concussions). former athletes reporting 4 or 5 concussions were nearly 1.5 times as likely to report symptoms of anxiety/depression; those reporting 6 or more were two times as likely to report symptoms. this relationship was found across all three sports individually as well. review sajsm vol. 33 no. 1 2021 8 sdsdsds table 1 continued. summary of general health questionnaire (ghq) studies on athletes author study design purpose population; country n; men/ women % ghq scoring method ghq cut off point prevalence incidence predictor outcome ghq mean score findings gouttebarge et al., 2018[37] observation al, prospective cohort symptoms of cmd professional rugby union players; mean: age 26; career duration 6; australia, england, france, ireland, italy, new zealand, pacific islands, south africa and wales 595 at baseline and 333 at follow up; 100/0 ghq method 3 32% 28% adverse life events; rugby career dissatisfac tion ghq score at baseline, there was 32% prevalence of anxiety/depression; there was a 28% incidence of anxiety/depression during the 12month follow up. although not statistically significant, recent adverse life events or career dissatisfaction were associated with the incidence of anxiety/ depression. hulley et al., 2007[18] observation al, crosssectional eating disorders in elite female distance runners elite distance runners from the uk and kenya aged between 15-30 (20.8 ± 3.7) athletes (82 uk and 75 kenyan) and non-athlete controls (97 uk and 101 kenyan); 0/100 likertscale uk athletes and cont rols (20.6 ; 21.4); kenyan athletes and control (15.9; 17.3) kenyan athletes scored lower than uk groups on the ghq; athletes scored lower than the controls. kenyan runners were less likely to report symptoms of anxiety/depression than uk runners. ivarsson et al., 2015[41] observation al, prospective cohort predictive ability of perceived talent devel opment environmen t (tde) on well-being elite swedish youth footballers aged 1316 years old (14.16 ± 1.00) 195; 100/0 likertscale ghq score tdeq (quality of talent developm ental environme nt) a high quality tde appears to be associated with higher levels of self-reported wellbeing among youth football players; players experiencing the lowest perceived tde quality reported the lowest level of well-being over time. kilic et al., 2017[19] observation al, crosssectional symptoms of common mental disorders and related stressors professional football and handball players (current and retired); age current/retired football players (25.8 ± 4.9/34.0 ± 4.9); age current/retired handball players (25.3 ± 4.5/35.0 ± 5.6); denmark 348 current & 345 retired football players ; 232 current & 230 retired hand ball players; 82/18 (current foot ballers) ; 79/21 (retired foot ballers); 51/49 (current hand ball players); 100/0 (retired handball players) ghq method 2 18% (current footballers); 19% (retired footballers); 26% (current handball players); 16% (retired handball players) severe injuries*; surgeries*; recent adverse life events* ghq score a prevalence of 18% and 19% anxiety/depression was observed for current and retired football players respectively; a prevalence of 26% and 16% anxiety/ depression was observed for current and retired handball players respectively; significant associations between a higher number of recent adverse life events and risk of anxiety/ depression in all athletes; in retired football players there were significant associations with a higher number of severe injuries and surgeries with risk of anxiety/depression. review 9 sajsm vol. 33 no. 1 2021 dsdsadsa table 1 continued. summary of general health questionnaire (ghq) studies on athletes author study design purpose population; country n; men/ women % ghq scoring method ghq cut off point prevalence incidence predictor outcome ghq mean score findings kilic et al., 2018[42] observational, prospective cohort severe musculoskel etal time-loss injuries and symptoms of common mental disorders professional footballers from national player unions; age (27 ± 5); duration of career (8 ± 5); finland, france, norway, spain, sweden 384 at baseline and 262 at follow up; 100/0 ghq method 3 32% ghq score; musculoske letal timeloss injuries musculos keletal time-loss injuries; ghq score 32% prevalence of anxiety/depression at baseline; not associated with the incidence of severe musculoskeletal timeloss injury. however, musculoskeletal injuries at baseline were associated with the incidence of anxiety/depression in the follow up period even when adjusted for age and adverse life events. niazi et al., 2014[20] observational, cross-sectional relationship between emotional intelligence and mental health in collegiate champions collegiate athletes of islamic azad university; age (22.35 ± 2.49); history of sports in years (9 ± 2); various sports; iran 192; ns ns ns self-control* ghq score significant positive correlation between emotional intelligence and mental health; self-control explains 76% of the variations in mental health. noblet et al., 2003[21] observational, cross-sectional predictors of the strain experienced by professional australian footballers (aussie rules) professional australian football players 255; 100/0 likertscale postfootball uncertainty* ; social support from work*; pressure to perform* ghq score post-football uncertainty, social support from work and the constant pressure to perform were significant predictors of psychological health. peretti-watel et al., 2004[22] observational, cross-sectional risky behaviour among elite student athletes elite student athletes competing at regional, national or international/oly mpic level; age (18.3); france 458; 65/35 likertscale smoking; cannabis use ghq score girls (15.2 ± 6.9); boys (11.3 ± 5.3) girls had a significantly higher ghq score than boys. ghq scores were significantly correlated with smoking and cannabis use among elite student athletes. quarrie et al., 2001[43] observational, prospective cohort association between potential risk factors and injury risk professional rugby union players; age (20.6 ± 3.7); new zealand 250; 100/0 ns ns ghq score injury no significant association of ghq score with injury risk. review sajsm vol. 33 no. 1 2021 10 dsadas table 1 continued. summary of general health questionnaire (ghq) studies on athletes author study design purpose population; country n; men/ women % ghq scoring method ghq cut off point prevalence incidence predictor outcome ghq mean score findings schuring et al., 2017a[23] observational , crosssectional association between osteoarthritis (oa) and symptoms of common mental disorders former elite athletes (rugby, football, ice hockey, gaelic sports and cricket); age (37 ± 6); duration of career (10 ± 5); duration of retirement (6 ± 5); finland, france, ireland, norway, south africa, spain, sweden and switzerland with oa (200) and without oa (402); 100/0 ghq method 4 31% (with oa); 25% (without oa) oa* ghq score oa might be a risk factor for developing symptoms of cmd in former elite athletes. prevalence of 31% and 25% for retired athletes with oa and those without oa respectively. oa was significantly associated with having more than 2 cmds. further, there was a significant association of oa with anxiety/depression in former ice hockey players. schuring et al., 2017b[44] observational , prospective cohort mental wellbeing of current and retired professional cricketers current (age: 27 ± 5) and former professional cricketers (age: 36 ± 6); duration of career (current: 6 ± 5), (former: 12 ± 6); south africa 116: 78 (current) and 38 (former) at baseline; 91/9 ghq method 2 37% (current); 24% (retired) 15% (current) significant injuries; surgeries; adverse life events*; career dissatisfaction * ghq score prevalence of 37% and 15% incidence over 6 months for anxiety/ depression in current cricketers; prevalence of 24% for anxiety/ depression in former cricketers. career dissatisfaction and adverse life events had positive associations with anxiety/ depression in current cricketers. sekizaki et al., 2017[45] randomised controlled trial effectiveness and contribution of internetbased cognitive behavioural therapy (icbt) to mental healthcare in a school setting high school athletes competing at a national level in various sports; japan 80: 40 intervention group and 40 controls; 100/0 ghq method ns pre: intervention and control (3;3.3); post: intervention and control (1.6; 2.2) school mental healthcare programme using icbt is suitable for students and useful for coping with stress and reducing depressed mood and anxiety (lower ghq scores) in young people, especially athletes. review 11 sajsm vol. 33 no. 1 2021 dsdsdsdsdsda table 1 continued. summary of general health questionnaire (ghq) studies on athletes author study design purpose population; country n; men/ women % ghq scoring method ghq cut off point prevalence incidence predictor outcome ghq mean score findings stephan, 2003[35] observational, prospective cohort repercussions of transition out of elite sport on subjective well-being olympic athletes (active and retired); athletes ages ranged from 27 to 35 years (retired: 31 ± 4; active: 29 ± 2); france 32: 16 retired and 16 active; 50/50 likertscale time 1, 2, 3: 25.06; 21.18; 19.56 at the time of retirement, retired athletes exhibited significantly decreased subjective well-being (mean ghq score = 25.06) compared to active athletes (mean ghq score = 21.18). however, as transitional athletes became used to retirement, their well-being increased over time (mean ghq score = 19.56). totterdell et al., 2001[24] observational, cross-sectional negative mood regulation (nmr) expectancies and sports performance professional cricketers from county cricket clubs; ages ranged from 17 to 38 years (25 ± 5); england 46; 100/0 likertscale 10.04 ± 5.21 mean ghq score (10.04) was not significantly correlated with performance over a season; it was significantly correlated with nmr, which itself is significantly correlated with performance. furthermore, nmr did not correlate with performance when well-being was covaried for. van ramele et al., 2017[36] observational, prospective cohort incidence of symptoms of common mental disorders retired professional footballers; age (35 ± 6); duration of career (12 ± 5); duration of retirement (4 ± 3); various 212 (baseline) and 194 (follow up); 100/0 ghq method 3 29% adverse life events ghq score highest incidence over 12 months was anxiety/depression (29%). however, there was no association between adverse life events and anxiety/depression. 96% of retired football players agreed that mental health can influence players during their career while more than half agreed that mental health affected their performance. more than 80% agreed that there is insufficient medical support for mental health for both current and retired footballers wilson et al., 2015[46] quasiexperimental effects of a diet and exercise intervention on body composition, metabolism, bone and mental health highly experienced jockeys; uk 10; ns ghq method 4 21% pre: 10.3 ± 4.3; post: 8.9 ± 3.8 there was a 21% prevalence of jockeys suffering from symptoms of anxiety/depression. mean ghq-12 score was 10.3 prior to the dietary intervention reducing to 8.9 postintervention. however, this was not statistically significant. * indicates results are significant (p<0.05); le, life event; ns, not specified. review sajsm vol. 33 no. 1 2021 12 conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: all authors conceptualised the need for a review. na performed the literature search and synthesis. na drafted the manuscript. all authors provided critical input and approved the final version. references 1. gulliver a, griffiths km, mackinnon a, et al. the mental health of australian elite athletes. j sci med sport 2015;18(3):255-261. 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[doi:10.1055/s-0035-1549920][pmid: 26212241] 47. american psychiatric association: diagnostic and statistical manual of mental disorders, 5th ed.:dsm-5 arlington, va: american psychiatric association; 2013. 48. world health organization. depression and other common mental disorders: global health estimates. geneva: world heal organization 2017. licence: cc by-nc-sa 3.0 igo original research 79 sajsm vol. 28 no. 3 2016 mixed drink increased carbohydrate oxidation but not performance during a 40 km time trial l hill, bsc (med)(hons), a n bosch, phd division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, cape town, south africa corresponding author: a n bosch (andrew.bosch@uct.ac.za) it is well-established that consuming exogenous carbohydrate during prolonged physical activity improves performance.[1,2] the role of exogenous carbohydrate intake is hypothesised to provide additional substrate for oxidation[3] specifically influencing performance by decreasing endogenous liver glycogen utilisation and preventing hypoglycaemia.[4,5] early research cited the maximum rate of exogenous carbohydrate oxidation to be ~1 g/min.[1] it was hypothesised that oxidation rates higher than 1 g/min were achieved by overcoming a limitation of a single carbohydrate at the intestinal absorption sites (sglt-1)[6,7] by utilising alternative carbohydrate transporters located in the intestine, such as glut5 for fructose.[5] this suggests the potential for improved performance. however, to date, only a handful of studies have investigated the effects of multiple carbohydrate (glucose or maltodextrin and fructose) ingestion on cycling performance parameters and whether the difference in exogenous carbohydrate oxidation between a multiple carbohydrate drink and single carbohydrate drink results in an improved performance.[7,8] in the first of these studies, a laboratory trial by currell and jeukendrup,[7] a marked improvement in cycling performance was attained when a multiple carbohydrate drink, containing mixed carbohydrates, was ingested compared to that of a single carbohydrate drink which contained a gp only. the authors concluded that the mechanism for the improvement in performance was due to the increased exogenous carbohydrate oxidation rate, which allowed a greater amount of carbohydrate to enter systemic circulation for subsequent oxidation by the working muscles. similarly, o’brien and rowlands[9] have shown that higher rates of exogenous carbohydrate oxidation with a multiple carbohydrate drink result in an improvement in performance over and above that of when an isocaloric single carbohydrate with concomitant lower oxidation rate is ingested. furthermore, the studies by rowlands et al.[10] and currell and jeukendrup[7] measured endogenous a carbohydrate oxidation rates in addition to performance parameters, however, exogenous oxidation rates were not measured and it was assumed that the oxidation rate of the multiple cho drink ingested was higher. the present study aimed to determine if a superior performance is attained when a multiple carbohydrate drink is ingested. specifically, time trial performances were compared in a single group of highly trained cyclists to determine whether a multiple carbohydrate drink (glucose: fructose in a 2:1 ratio) confers a performance advantage over that of a single carbohydrate drink (glucose-polymer only), the physiological parameters of lactate, insulin and glucose concentrations, substrate oxidation (total, endogenous and exogenous) and respiratory exchange, will be measured, which may explain the underlying mechanisms that relate to any performance differences. methods study design a double-blind randomised crossover design was employed in the study. the drink order was randomised to ingest either the glucose-polymer only (gp) or a multiple carbohydrate (mixed) drink during the first trial, while the alternative drink was ingested in the second trial. prior to participation in the trial, all participants completed a physical activity readiness and training history questionnaire to assess eligibility. informed consent for the study was obtained from the participants, which was approved by the human research ethics committee of the faculty of health sciences, university of cape town, south africa. the testing for each participant took place over three background: the present study aimed to determine whether consuming a glucose polymer (gp) and fructose would result in increased carbohydrate oxidation rates and improve 40 km time trial performance compared with an isocaloric gp-only drink. methods: eight well-trained male competitive cyclists (vo2max 62.7 ± 9.4 ml/kg/min, power output 5.1 ± 0.6 watts/kg) participated in three visits consisting of a peak power output (wmax) and vo2 max test and two separate visits of a 105 minute steady state ride (at 65% wmax), followed by a 40 km time trial. participants received 1.2 g/min of either a gp or mixed drink every 15 min. results: no differences were found in the 40 km performance between gp (69:14 min ± 4.12, mean ± sd) and the mixed drink (66:58 min ± 4.51, mean ± sd) trials (p = 0.289). there were no differences in blood glucose or lactate between the trials. no differences in total oxidation were found in either carbohydrate or fat oxidation rates; however, exogenous carbohydrate oxidation was significantly different between the gp drink trials at t=90 min (gp: 0.96 ± 0.36 g/min; mixed drink: 1.53 ± 0.48 g/min; p = 0.041, mean ± sd). conclusion: the present study found no improvement in 40 km time trial time between an isocaloric gp-only or a gp and fructose drink, and no differences in any of the measured variables other than exogenous carbohydrate oxidation at 90 minutes during the pre-time trial steady state ride. keywords: multiple carbohydrate, cycling, endurance, glucose, fructose s afr j sports med 2016;28(3):79-84. doi: 10.17159/2078-516x/2016/v28i3a1326 mailto:andrew.bosch@uct.ac.za http://dx.doi.org/10.17159/2078-516x/2016/v28i3a1326 original research sajsm vol. 28 no. 3 2016 80 weeks and consisted of an anthropometry and peak power output test on the first visit, followed by a three-five day recovery period. the second visit (fig.1) to the laboratory was the first performance trial. seven to 14 days later, participants returned for the second performance trial, using the alternate carbohydrate drink. participants eight (n=8) well-trained male cyclists were recruited for the study from local cycling clubs. descriptive data of the participants is summarised in table 1. participants ate a standardised breakfast (comprised of kellogg’s corn flakes and skim milk) two hours before each trial as previously described in[11]. peak power output test anthropometry, including height, weight and body fat percentage were obtained through skinfold measurements of the cyclists. skinfold measurements were taken from the bicep, tricep, calf, subscapular, suprailiac, abdominal and thigh. subsequent to the anthropomorphic measures, participants performed a peak power output test (ppo) using their own bicycle attached to a computrainer (computrainertm pro 3d ergometer, racermate, seattle, usa). performance testing lamberts and lambert sub-maximal cycle test (lsct) and peak power output (ppo) prior to commencement of the lsct, a cannula (20 gauge. nipro, osaka, japan) was inserted into the antecubital vein of the arm and a baseline blood sample of 5 ml was drawn for subsequent biochemical analysis. immediately after ingesting one of the test drinks, participants completed a lsct to calculate standardised hr-based workload data for each cyclist. rpe, power and heart rate for each of the lsct stages were recorded for subsequent analysis. a detailed description of the lsct and ppo protocol can be found in lamberts et al[12]. pre time trial steady state ride (pttss) and 40 km time trial after the start of the preliminary analysis, a thematic framework was constructed in which to consolidate similar themes and perceive the differences from others. the themes identified in the data set were categorised as: psychosocial barriers and professional and programme-related barriers to progress in the programme. carbohydrate drink and ingestion schedule each participant ingested either glucose-polymer only (gp) (refuel cc, muizenberg, south africa) or a glucosepolymer:fructose mixed drink. the type of carbohydrate drink ingested was randomised for each participant’s first trial and the alternative drink was given at the subsequent trial. the mixed drink contained gp and fructose (lifestyle food crystalline fructose. dis-chem (pty) ltd, midrand, south africa) in a 2:1 ratio. both ingested drinks had a concentration of 12% (12 g/100 ml) to deliver 1.2 g/min of carbohydrate. the drinks were artificially flavoured and coloured with a sugar-free, flavoured cordial. the participants ingested 400 ml of the selected drink immediately before the commencement of the pttss. one hundred and fifty ml was ingested every 15 minutes throughout the 105 min pttss (t= 0, 15, 30, 45, 60, 75, 90 and 105 mins). during the subsequent time trial, 150 ml of one of the test drinks was consumed at the start (0%) and then at 25%, 50% and 75% respectively during the completion of the time trial distance. biochemical analyses blood samples (for plasma, glucose and lactate analysis) were collected using vacuette tubes (4 ml vacuette, greiner bio-one, kremsmunster, austria) and were stored on ice until analysed. rer and respiratory calculations were done according to faryn.[13] and 13c calculations were done according to pirnay et al.[14] performance and heart rate measures during the time-trial, in addition to time to complete the 40 km, 1 km split times were recorded. average power output (w) was calculated for each of the 1 km intervals during the 40 km, as well as the average power output (mean ± sd) for the entire time trial. heart rate was monitored during the entire experiment and then averaged for 5 min intervals using a suunto t6 heart rate monitor (suunto®, oy, vantaa, finland). statistical analyses statistical analyses were performed using statistica 10 (statsoft inc.) and significance was accepted at p< 0.05. data are presented as means ± sd. comparison between the gp and mixed drink’s completion time of the 40 km time-trial, as well as the 1 km interval splits, peak power output, insulin, glucose and lactate concentrations, rer and oxidation rates calculations were performed using repeated measures analysis of variance (anova). results participant characteristics participant characteristics are summarised in table 1 respiratory measurements none of the measured variables (table 1) were found to be significantly different between trials. total carbohydrate oxidation, fat oxidation and rer during the pttss were not significantly different between the two trials (fig. 2). biochemical analysis glucose concentrations (fig. 3), insulin concentrations and blood lactate concentrations were shown to change over the course of the pttss, but were not significantly different between trials. carbohydrate oxidation endogenous carbohydrate (fig. 4a) oxidation was not found to be significantly different between drinks trials at any of the time points; however, the data showed a trend towards original research 81 sajsm vol. 28 no. 3 2016 fig. 1. schematic representation of protocol for performance trials table 1. summary of participant results (n=8), ppo test (visit 1) and respiratory measures during the pttss participant characteristics anthropometry age (y) height (cm) weight (kg) body fat % cycling history (y) training load (hours/week) 26.1 ± 5.4 179.6 ± 6.8 75.6 ± 10.1 8.6 ± 1.7 7.0 ± 3.6 17.6 ± 5.2 ppo test ppo (watts) rpo (watts/kg) absolute vo2 (l/min) relative vo2 (ml/kg/min) 406 ± 38 5.1 ± 0.6 4.7 ± 0.4 62.7 ± 9.4 respiratory measurements (pttss) vo2 (l/min) vco2 (l/min) vo2 (ml/kg/min) % vo2 max rer cho ox fat ox (p) trial 0.932 0.977 0.923 0.748 0.639 0.787 0.665 (p) time 0.102 p<0.05 0.259 p<0.05 p<0.05 p<0.05 p<0.05 (p) interaction 0.661 0.839 0.720 0.352 0.970 0.834 0.522 effect size 0.106 0.046 0.014 0.098 0.533 0.427 0.538 ppo, peak power output; rpo, relative power output; rer, respiratory exchange ratio; pttss, pre time trial steady state; cho, carbohydrates; ox, oxidation; y, years; p, p-value fig. 2. total carbohydrate oxidation, fat oxidation and rer during the pttss (t=0 – 90 min). mean values of vo2 and vco2 were measured for 5 min every 15min. these were used to calculate rer, total cho and total fat oxidation. gp trial (black circles) and mixed drink trial (white circles); no signficant differences were found. error bars indicate 95% confidence interval. original research sajsm vol. 28 no. 3 2016 82 fig.3. plasma insulin, lactate and glucose concentrations during the time trial. gp (black circles) or mixed drink (white circles). no significance difference was found between the drink trials. error bars indicate 95% confidence interval. fig. 4. endogenous and exogenous carbohydrate oxidation during pttss (t= 45 – 90 min). endogenous oxidation was not significantly different at any of the intervals (p=0.275); however, the data show a trend toward significance at the 90 minute interval (p=0.078). no statistical difference was found at 45-, 60and 75 minute intervals for exogenous cho oxidation but a significant difference was found at the 90 minute interval (p= 0.041). error bars indicate sd. fig. 5a. individual time trial differences of participants (each bar represents an individual participant). a positive δ time indicates faster time to completion in mixed drink trial compared to gp. fig. 5b. final time trial completion for the gp (69:14min ± 4.12, mean ± sd) and the mixed drink (66:58min ± 4.51, mean ± sd) trials were not significantly different between trials (p= 0.289). significance at the 90 minute time point (gp: 2.38 ± 0.77 g/min; mixed drink: 1.99 ± 0.12 g/min; p=0.078, mean ± sd). exogenous carbohydrate oxidation (fig. 4b) determined from expired air samples (13c abundance in breath samples) from the pttss was significantly different between the mixed drink and gp trials at 90 minutes (gp: 0.96 ± 0.36 g/min; mixed drink: 1.53 ± 0.48 g/min; p=0.041, mean ± sd). no differences were found at the 45-, 60and 75 minute time points respectively (p=0.083). time trial performance measures 40 km time trial total time to completion for the 40 km time trial and each of the individual 40 km performances are shown in fig. 5a. no significant differences were found in the 1 km split times (gp: 1 min 43sec ± 7.3 sec ; mixed drink: 1 min 41sec ± 6.5 sec; p=0.696, mean ± sd), 1 km average rpm (gp: 88 ± 9 rpm; mixed drink: 91 ± 9 rpm; p=0.731, mean ± sd and 1 km average power output (gp: 230 ± 38 w; mixed drink: 242 ± 41 w; p=0.611, mean ± sd); neither was there any significant change during the 40 km time trial (fig. 5a). there was no significant difference in time to complete the time trial (fig. 5b) between gp (69:14 min ± 4.12, mean ± sd) and mixed drink (66:58 min ± 4.51, mean ± sd) performance trials (p=0.289). heart rate and rating of perceived exertion (rpe) no significant differences were found in heart rate (gp: 161 ± 5 bpm; mixed drink: 161 ± 6 bpm; p=0.845, mean ± sd) between the trials in both the pttss and 40 km time trial rides (gp: 165 original research 83 sajsm vol. 28 no. 3 2016 ± 2 bpm; mixed drink: 166 ± 2 bpm; p=0.956, mean ± sd). rpe (borg scale units) increased significantly over the course of the pttss and 40 km time trial but was not significantly different between drink trials during the pttss (p=0.373) and 40 km time trial rides (p=0.223). discussion in contrast to previous research,[7,8,10,15] no improvement in performance was recorded during a 40 km laboratory time trial between the gp and the mixed drinks (p=0.289). triplett et al.[8] showed an 8.1% improvement in time trial performance when participants ingested approximately 144 g (or 2.4 g/min) of drinks containing either gp only, or a gp and fructose (1:1 ratio) mixed drink. the improvement in performance was attributed to maintenance of a significantly higher average power output during the ingestion of the mixed drink as compared to the gp trial. similar results were reported by currell and jeukendrup[7] in which cyclists, ingesting 1.8 g/min, improved by 8% in a time trial in which a set amount of work was to be completed as quickly as possible following a period of steady state exercise for 120 min at 55% wmax. however, rowlands et al.[10] obtained similar findings to those of the present study, observing only a modest improvement in performance in both a race (1.8% ± 1.8%, mean ± sd) and laboratory trial (1.4% ± 0.8%, mean ± sd) with participants ingesting 1.2 g/min. this is further supported by bauer et al.[15] the present study’s objective was to determine whether a more modest concentration of mixed carbohydrate drink (12%) can increase carbohydrate oxidation above 1 g/min and thereby improve performance. besides not finding any improvement in cycling performance, the present study also found no difference in total carbohydrate oxidation between the gp and mixed drink trials. however, a significant difference in exogenous oxidation (fig. 4b) was found after 90 minutes during the pttss (p=0.041). in the study by jentjens and jeukendrup[5], participants ingested a drink that contained 2.4 g/min of mixed carbohydrates during a 150 min of cycling exercise at 60% of vo2 max which resulted in a peak exogenous oxidation rate of 1.75 g/min at the 150 minute time point. the gp drink resulted in a significantly lower exogenous oxidation rate of 1.06 g/min. this is in agreement with this present study as only a significant difference in cho oxidation at the 90 minute time point during the pttss was detected suggesting that the effects of ingesting an exogenous carbohydrate may only become prevalent after 60 minutes of prolonged exercise. the increase in oxidation rates in a mixed carbohydrate drink is hypothesised to be as a result of the increased uptake of mixed carbohydrates by glut4 and glut5 transporters respectively in the brush border of the gut.[5,7,10] it is theorised that when gps are ingested alone, the sglt-1 transporters become saturated, ultimately limiting the uptake of glucose into the body. the ingestion of a multiple carbohydrate drink is suggested to overcome this limitation by utilising alternative carbohydrate transporters, specifically the glut5 transporters which function to absorb other sugar isomers such as fructose.[6,7,12] however, in the present study, the nature of the protocol utilised was particularly intense (participants exercised at 65% wmax for 105 minutes during the pre-time trial steady state ride before completing a 40 km time trial, resulting in participants exercising at 76-82% of vo2 max and 85-90% of hrmax) compared to a number other performance trials, in which moderate exercise intensities were employed. these authors can only stipulate that the absence of significant differences between the gp and mixed drinks can be attributed to the demanding study design, the participants may have experienced fatigue and near muscle glycogen depletion[1,4] before the commencement of the performance component, masking a potential effect of the additional exogenous carbohydrate. the rationale behind the utilisation of such a demanding protocol was an attempt to simulate as closely as possible the physiological stress that would be encountered during a prolonged cycling road race. although the present study failed to find a statistical improvement in performance over the 40 km between the two drink trials, it was found that the ingestion of the mixed drink resulted in a faster time trial completion than the gp drink. this research also demonstrated that there was a significant more exogenous carbohydrate oxidation at t=90 min in the mixed drink trial compared to the gp drink in the pttss, supporting previous studies findings.[7,15] therefore this study contributes to the growing scientific body of the importance of cho ingestion during prolonged and often intense exercise, such as can be seen in events such as the tour de france. however, the study is not without limitations. the sample size was small, and therefore including more participants in the future may produce clearer results. conclusion as far as the authors can ascertain, this is the first study to utilise the well-established laboratory-based time trial as a measure of endurance performance, in conjunction with pretime trial steady state exercise in order to reassess the potential performance-enhancing effect of ingesting a multiple carbohydrate drink compared to a single carbohydrate drink. the present study found no improvement in a 40 km time trial time between an isocaloric gp only or a gp and fructose drink, and no differences in any of the measured variables other than exogenous carbohydrate oxidation at 90 minutes during the pre-time trial steady state ride. conflict of interest: there are no conflicts of interest to report. references 1. hawley ja, bosch an, weltan sm, et al. effects of glucose ingestion or glucose infusion on fuel substrate kinetics during prolonged exercise. eur j appl physiol occup physiol 1994;14:27-42. [pmid: 8076616] 2. bosch an, dennis sc, noakes t. influence of carbohydrate loading on fuel substrate turnover and oxidation during prolonged exercise. j appl physiol 1993;74:1921-1927. [pmid: 8514712] 3. jeukendrup ae, wagenmakers aj, stegen jh, et al. carbohydrate original research sajsm vol. 28 no. 3 2016 84 ingestion can completely suppress endogenous glucose production during exercise. am j physiol 1999;276(4 pt 1):e672-e683. [pmid: 10198303] 4. bosch an, weltan sm, dennis sc, et al. fuel substrate turnover and oxidation and glycogen sparing with carbohydrate ingestion in noncarbohydrate-loaded cyclists. pflugers arch eur j physiol 1996;432(6):1003-1010. [pmid: 8781194] 5. jentjens rl, jeukendrup ae. high rates of exogenous carbohydrate oxidation from a mixture of glucose and fructose ingested during prolonged cycling exercise. br j nutr 2005;93:485-492. [pmid: 15946410] 6. jentjens rl, shaw c, birtles t, et al. oxidation of combined ingestion of glucose and sucrose during exercise. metabolism 2005;54:610-618. [pmid: 15877291] [doi: 10.1016/j.metabol.2004.12.004] 7. currell k, jeukendrup ae. superior endurance performance with ingestion of multiple transportable carbohydrates. med sci sports exerc 2008;40(2):275-281. [doi:10.1249/mss.0b013e31815adf19] 8. triplett d, doyle ja, rupp jc, et al. an isocaloric glucose fructose beverage’s effect on simulated 100-km cycling performance compared with a glucose-only beverage. int j sport nutr exerc metab 2010;20(2):122-131. [pmid: 20479485] 9. o’brien wj, rowlands ds. fructose-maltodextrin ratio in a carbohydrate-electrolyte solution differentially affects exogenous carbohydrate oxidation rate, gut comfort, and performance. am j physiol gastrointest liver physiol 2011;300(1):g181-9. [doi:10.1152/ajpgi.00419.2010] 10. rowlands, ds, swift m, ros m, et al. composite versus single transportable carbohydrate solution enhances race and laboratory cycling performance. appl physiol nutr metab 2012;37:425-436. [pmid: 22468766] [doi: 10.1139/h2012-013] 11. schabort ej, bosch an, weltan sm, et al. the effect of a pre-exercise meal on time to fatigue during prolonged cycling exercise. med sci sports exerc 1999;30:464-471. [pmid: 10188753] 12. lamberts rp, swart j, noakes td, et al. a novel submaximal cycle test to monitor fatigue and predict cycling performance. br j sport med 2011;45:797-804. [pmid: 19622525] [doi: 10.1136/bjsm.2009.061325] 13. frayn k. calculation of substrate oxidation rates in vivo from gaseous exchange. j appl physiol 1983;55:628-634. [pmid: 6618956] 14. pirnay f, lacroix m, mosora f, et al. effect of glucose ingestion on energy substrate utilization during prolonged muscular exercise. eur j appl physiol occup physiol 1977;36(4):247-254. [pmid: 902638] 15. baur da, schroer ab, luden nd, et al. glucose-fructose enhances performance versus isocaloric, but not moderate, glucose. med sci sports exerc 2014;46(9):1778-1786. [doi:10.1249/mss.0000000000000284]. editorial 35 sajsm vol. 28 no. 2 2016 health-related mobile apps and behaviour change while our knowledge about physical activity and health, physical performance and the risk of injury increases in leaps and bounds, the conversion of this information into action and changed behaviour lags behind. there seems to be a sticking point which often causes a delay in new knowledge being adopted and implemented. many examples exist, most notably, smoking. it took several decades for the prevalence of smoking to be reduced, despite an abundance of information showing the negative effects of active and passive smoking on human health. a less obvious example is the impact of physical activity, or lack of it, on health. evidence from studies around the world show the positive effects of regular, moderate exercise, which include the impact of physical activity on performance, bone health, metabolic health, mental health and cognitive performance. studies also show how regular exercise ameliorates some of the symptoms of ageing. for example, elderly people with a high level of physical activity are less likely to fall, which can result in an injury triggering a downward spiral in mobility and independence. it goes without saying that the reduction of falls will have a massive impact on both the well-being of the individual and the financial burden of health care costs. scientists have been challenged by the fact that a large portion of the population is less physically active than recommended, in spite of the overwhelming body of information on the positive benefits of physical activity. even after much input from behavioural scientists, this change has been slow. superficially it seems that the barriers between knowledge and behaviour need to be identified and removed. however, this is more complicated than it sounds because the barriers are dependent on and responsive to personal preference, age, cultural group and socioeconomic status. a new wave of evidence shows that behavioural changes may be mediated through specific apps on mobile devices. between 2013 and 2014 the global use of smart phones increased by 406 million. [1] there are now just under two billion mobile devices in use. a recent count estimated about 31 000 health-related apps. [2] these apps are designed to prevent and manage chronic disease, monitor health behaviours and vitals. it is not unusual for someone in a meeting to stand up, politely commenting that the app on their smart phone has signalled that they have been seated for too long. or for someone to comment that they need to walk during the lunch break to meet their 10 000 steps goal for the day. there is compelling evidence, certainly at the anecdotal level, that these apps are having an effect on health-related behaviour. at a higher level of credibility, several published studies have utilised apps in health behaviour interventions. a systematic review of the published studies on apps used in health behaviour interventions supports the anecdotal observations. [2] of the ten studies in the review which targeted physical activity as a primary measure, eight studies reported positive outcomes with the participants increasing their physical activity. the systematic review concluded that mobile apps might be considered an acceptable means of administering health interventions. however, more studies with larger samples and a rigorous research design are needed. researchers are encouraged to conduct rigorous randomly controlled studies on this subject. this is an area that the south african journal of sports medicine is going to actively promote in the future. mike lambert editor-in-chief s afr j sports med 2016;28(2):35. doi: 10.17159/2078-516x/2016/v28i2a1568 references 1. stoyanov sr, hides l, kavanagh dj, zelenko o, tjondronegoro d, mani m. mobile app rating scale: a new tool for assessing the quality of health mobile apps. jmir mhealth uhealth 2015;3(1):e27 doi: 10.2196/mhealth.3422 2. payne he, lister c, west jh, bernhardt jm. behavioral functionality of mobile apps in health interventions: a systematic review of the literature. jmir mhealth uhealth 2015;3(1):e20 doi: 10.2196/mhealth.333 http://dx.doi.org/10.17159/2078-516x/2016/v28i2a1568 http://doi.org/10.2196/mhealth.3422 original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license strengthening the biokinetics workforce for improved services: a human resources for health review from 2000 to 2020 r tiwari,1 phd; hw grobbelaar,2 phd; c vermaak,3 phd; u chikte,1 phd 1 division of health systems and public health, department of global health, faculty of medicine and health sciences, stellenbosch university, tygerberg, south africa 2 division of sport science, department of exercise, sport and lifestyle medicine, faculty of medicine and health sciences, stellenbosch university, stellenbosch, south africa 3 division of movement science and exercise therapy, department of exercise, sport and lifestyle medicine, faculty of medicine and health sciences, stellenbosch university, stellenbosch, south africa corresponding author: hw grobbelaar (hgrobbelaar@sun.ac.za) stellenbosch university was the first south african university to offer a programme in physical education.[1] biokinetics developed from the south african physical education programme that can be traced to the 1930s.[2] it is a south african health profession that functions predominantly in the private healthcare sector. biokineticists register with the health professions council of south africa (hpcsa), which regulates the profession.[3] the biokinetics association of south africa (basa) is the representative body, with a vision for the profession ‘to be a recognised leader and vital collaborator within the health sector’.[4] biokinetics originated in south africa four decades ago when the first scope of practice was published in the south african government gazette in 1983[2] and it has expanded internationally. biokineticists in the united kingdom are currently seeking registration as healthcare professionals,[5] whilst the profession signed a memorandum of understanding with the professional organisation exercise and sport science australia.[6] biokineticists form part of multidisciplinary teams alongside medical doctors, physiotherapists, dieticians, psychologists, etc.[3] they operate within the pathogenic (illness care and prevention), and fortogenic (health promotion) paradigms.[2] the word ‘biokinetics’ is derived from ‘bio’ meaning life and ‘kinesis’ meaning movement.[3] these exercise therapy professionals use exercise and physical activity to treat pathologies, focussing on injury rehabilitation, promotion of health and quality of life, and the prevention and management of chronic diseases of lifestyle (cdl), as well as secondary and associated conditions.[7] biokineticists use physical activity and personalised exercise prescription as a therapeutic modality for final phase rehabilitation and injury management, prevention and management of chronic illnesses, lifestyle diseases and disabilities.[2,8] physiotherapists assess, treat and manage a variety of injuries, ailments and movement disorders to restore normal functioning, minimise pain and dysfunction through exercise and hands-on physical therapy, i.e. mobilisation, manipulation and massage.[9] biokineticists have an important role to play in view of the estimation that more than a billion individuals (15% of the world population) live with functional disabilities because of global increases in the burden of non-communicable diseases (ncds) and musculoskeletal (msk) disorders.[10] about 74% of the total number of years lived with disability (yld, with one yld equalling one full year of healthy life lost because of disability or ill-health) are because of health conditions that cause functional restrictions that could benefit from exercise rehabilitation.[11] exercise rehabilitation benefits the individual and society at large by enhancing one’s independence, the ability to return to work, and participation in other social roles. background: biokinetics is a south african (sa) health profession within the private health care sector. biokineticists register with the health professions council of sa (hpcsa). objectives: to describe the demographic trends of hpcsa registered biokineticists from 2000 to 2020 to understand the supply and status of human resources for health within the profession. methods: the following data were collected and analysed: i) health personnel category, ii) geographical location, iii) age, iv) sex, and v) population category. results: the number of hpcsa registered biokineticists grew from 136 in 2000, to 1831 in january 2020 (67.8% women, 32.2% men). there was a sharp decline in numbers after the age of 45 years. the western cape (5.8) and gauteng (5.1) provinces had the most biokineticists per 100 000 of the population, whilst smaller provinces like kwazulu-natal (1.6), mpumalanga (1.6), north-west (1.6) and limpopo (0.9) lagged. the demographic profile of registered biokineticists changed steadily from 2000 to 2020. registered biokineticists classified as white decreased from 91.6% to 80.4%, whilst substantial increases were observed among black (5.0% to 8.3%), coloured (0.02% to 5.3%) and indian/asian (0.02% to 6.0%) biokineticists. thirteen tertiary institutions offered biokinetics programmes in 2022. seven offered the 3+1-year (honours) programme and six have migrated to a 4-year professional degree. conclusion: the profession is well established, growing, and dominated by women. the demographic profile has transformed steadily; however, the need to transform the profession remains strong. strengthening investments aimed at the employment of biokineticists in the public health sector may serve as a key turning point for healthcare workforce planning. keywords: clinical exercise therapy, hpcsa registration, training s afr j sports med 2023;35:1-8. doi: 10.17159/2078-516x/2023/v35i1a14184 http://dx.doi.org/10.17159/2078-516x/2023/v35i1a14184 https://orcid.org/0000-0002-2895-8099 http://orcid.org/0000-0003-0616-5933 https://orcid.org/0000-0002-5078-8989 https://orcid.org/0000-0002-7985-2278 original research sajsm vol. 35 no.1 2023 2 it also reduces the costs for care and support, as well as the length of hospitalisation and re-admission rates.[12,13] biokineticists are critical in meeting the current burden of disease by contributing to the prevention, promotion, treatment and support of individuals with functional capacity deficits and disabilities.[3,14] they promote active lifestyles among individuals with ncds through exercise, reducing the effects of sedentary behaviour and enhancing the ability to perform activities of daily living.[3,14] south africa as a developing country faces a quadruple burden of disease. the prevention and treatment of ncds is already marginalised because of the high prevalence of communicable diseases. the secondary and associated conditions seen with communicable diseases (e.g. human immunodeficiency virus (hiv) / acquired immunodeficiency syndrome (aids) and tuberculosis), maternal and child mortality, ncds (e.g. hypertension and cardiovascular diseases, diabetes, cancer, mental illnesses and chronic lung diseases, such as asthma), as well as injury and trauma further burden the under-resourced health sector.[15] the number of ylds is rising because of the decrease in mortality rates of south africans with such conditions, as well as the rising ageing population.[16] the increase in functional disability places a greater demand on physical exercise rehabilitation to restore functional ability and quality of life for affected individuals.[16] unfortunately, only 26% of people living in southern africa receive the exercise rehabilitation they need.[11] on the health workforce front, south africa needs to plan, support and upscale the supply pipeline of biokineticists to meet the health needs of society.[3] this study aims to describe the demographic trends of biokineticists registered with the hpcsa from 2000 to 2020 as the first step towards understanding the supply and status of human resources for the health of biokineticists in south africa. this study is inspired by a national need to review the biokineticist workforce to aid in the provision of a more robust and evidence-informed priority setting for health promotion, maintenance of physical abilities and final phase exercise rehabilitation. methods ethical approval and a waiver of informed consent for this retrospective study was obtained from the stellenbosch university health research ethics committee (hrec no: x21/05/009). the study was a retrospective record-based review of the hpcsa database from 2000 until 2020. a similar approach was adopted to that of earlier studies.[17,18] relevant data were recorded using a data collection sheet with the following variables: (i) category of health personnel (professional board of physiotherapy, podiatry and biokinetics), (ii) geographical location, (iii) age, (iv) sex, and (v) population category. the term ‘population’ was used in line with the definitions in the population registration act (act no. 30 of 1950), which previously classified south african citizens into four major population categories: white, coloured, indian/asian and black.[19] although the legislation was repealed in 1991, these population categories are still used in reporting in sectors such as the department of higher education and the department of health. racial data are still important in monitoring the redress in the education and training of health professionals who were previously denied access to such training in terms of the apartheid legislation. the dataset was accessed, collated, and analysed by the leading author and the team members crosschecked the accuracy. data were entered into a microsoft excel 2016 spreadsheet and analysed using the statistical package for the social sciences (spss version 22.0). frequency distributions, cross tabulations and graphical representations were used as descriptive statistical methods. anonymity and confidentiality of all hpcsa registered biokineticists were ensured because the data accessed from the hpcsa and presented in this paper was kept de-identified. results a total of 136 biokineticists were registered with the hpcsa in january 2000, and the number increased to 1831 in 2020, of which 19 were foreign nationals. the geographical distribution, age breakdown, demographic factors (sex and population group) for the 2020 data follows. geographical (provincial) distribution in 2020, most biokineticists were in gauteng (43.2%), the western cape (22.4%) and kwazulu-natal (10.2%). the northern cape (1.5%), limpopo (3.0%) and the north-west province (3.5%) had the lowest numbers. the availability of biokineticists per 100 000 of the population was the highest in the western cape at 5.8, followed by gauteng at 5.1 and the free state at 3.4. the lowest availability was in the limpopo province at 0.9 biokineticists per 100 000 of the population, with kwazulu-natal, mpumalanga and the north-west province lagging with 1.6 each (see figure 1 and table 1). fig. 1. geographical distribution of hpcsa registered biokineticists in south africa (january 2020) original research 3 sajsm vol. 35 no.1 2023 age distribution in 2020, most registered biokineticists were under the age of 40 years (79.2%). there was a sharp decline in the number of registered biokineticists after the age of 45 years (see figure 2). demographic profile of registered biokineticists (sex and population group) figure 3 depicts the 2020 data for sex and population groups of registered biokineticists. in the workforce, 67.8% of the biokineticists were women (n = 1241) compared to 32.2% men (n = 590). the change in the population group data from 2000 to 2020 is shown in figure 5. growth in the number of biokineticists in south africa over the past decade (2010 to 2020), the number of registered biokineticists has almost tripled. there has been an overall increase of 1246.32% over the last 20 years. the ratio of biokineticists per 100 000 of the population has also increased from 0.3 in 2000 to 3.1 in 2020 (see figure 4). south africa had a population of 43054000 in 2000, which grew steadily to 59622351 in 2020. population group trends from 2000 to 2020 in south africa figure 5 depicts changes in the population group characteristics in five-year intervals (2000 to 2020). in 2000, 91.6% of the registered biokineticists were white, 5.0% black, and 0.02% coloured and indian/asian, respectively. in 2010, the biokineticists who were identified as white reduced to 87.5%, while indians/asians increased to 4.4%, coloured to 4.1% and black to 4.0%. this trend continued so that by 2020 the biokineticists who were identified as white reduced to 80.4%, whilst indian/asian, black, and coloured biokineticists increased to 6.0%, 8.3% and 5.3%, respectively. table 1. geographical distribution of biokineticists by province in south africa in 2020 province number percentage of total province population (2020) biokineticists per 100 000 population 1 gauteng 783 43 15 488 137 5.1 2 western cape 405 22 7 005 741 5.8 3 kwazulu-natal 185 10 11 531 628 1.6 4 eastern cape 118 6 6 734 001 1.8 5 free state 101 6 2 928 903 3.4 6 mpumalanga 75 4 4 679 786 1.6 7 north-west 64 4 4 108 816 1.6 8 limpopo 54 3 5 852 553 0.9 9 northern cape 27 2 1 292 786 2.1 total* 1812 100 59 622 351 3.0 * excluding foreign and unknown categories fig. 2. age distribution of hpcsa registered biokineticists in south africa (january 2020) fig. 3. sex and population group distribution of hpcsa registered biokineticists in south africa (january 2020) original research sajsm vol. 35 no.1 2023 4 demographic trends by age, population group and sex figure 6 tracked the demographic variables by age, population group, and sex from 2000 to 2020. it showed that in 2020, women from the population group classified as white dominated the biokinetics workforce across all age categories except for the 55to 65-year-olds. the number of biokineticists decreased with age across all population groups, with the decrease noticeably higher in the population classified as white. the largest proportional growth between 2015 and 2020 was noted among the black biokineticists for both men and women. training and education table 2 lists the 13 tertiary institutions accredited to offer biokinetics programmes in 2022 that enables registration with the hpcsa. the university of kwazulu-natal will not offer the programme after 2022. of the 12 institutions offering programmes in 2023, four are based in the gauteng province (33.3%), three in the western cape (25.0%), and one in each of the eastern cape, free state, kwazulu-natal, limpopo, and north-west provinces (8.3% each). mpumalanga and the northern cape do not offer biokinetics programmes. two new universities were set up in these provinces in 2014, but they have restricted academic offerings. the table also indicates the institutions that offer master’s and phd programmes. students in these research programmes could focus on biokinetics-related topics, but the ensuing qualifications are not needed for registration, neither does it enable hpcsa registration. discussion biokineticists mainly operate in the private healthcare sector, and the geographical distribution closely resembles the distribution of the capital of each province. the number of tertiary institutions that offer biokinetics programmes also influences the proportion of registered biokineticists per province (e.g. gauteng and western cape, with four and three institutions respectively). the data suggest that the profession is comprised of younger graduates, and there has been exponential growth over the past two decades. however, the profession is still quite young. by 2000, there were only 136 registered biokineticists, which partly explains the declining numbers of those older than 45 years. women (67.8%) dominated the profession; however, not to the same extent as hpcsa registered physiotherapists (82.9%).[17] socio-economic fig. 4. hpcsa registered biokineticists and population ratios from 2000 to 2020 in south africa fig. 5. five-yearly population group trends of hpcsa registered biokineticists (2000-2020) original research 5 sajsm vol. 35 no.1 2023 factors were proposed as contributing reasons why physiotherapy is a feminine health care profession.[20] overall, there were more registered student women than men (57% vs 43%) at stellenbosch university,[21] suggesting that academic performance also contributed to this trend. reasons for the new four-year professional degree includes enhancing the eligibility for the public health sector,[3] and addressing the insufficient experiential training or clinical work-integrated learning in comparison to physiotherapy and occupational therapy.[22] until recently, biokineticists were exclusively trained at honours (fourth year) level, after completing undergraduate qualifications in human movement studies/science, sport science, kinesiology or ergonomics. honours students register as biokineticists-intraining with the hpcsa and basa, and complete one of the two years of internship at their respective universities during the honours year. after graduating (and passing the practical clinical assessment), the biokineticists-in-training complete the second year of internship with an hpcsa-accredited training institution or private practice for which they may receive a salary.[3] completion of the internship and board examination allows for registration with the hpcsa as a biokineticist. the revised scope of the profession and minimum standards for training (mst) for physiotherapy, podiatry and biokinetics (ppb) was amended and approved by the ppb board in october 2019 with immediate effect.[8] all training programmes should follow the new mst by the next accreditation visit (5-year accreditation cycle). the hpcsa’s mandate is to regulate health professions and to assess if training institutions meet the mst to ensure equitable qualifications. the ppb board noted that it cannot prescribe how institutions develop their programmes to meet the exit level outcomes. however, the ppb education, training and registrations committee strongly recommended in 2020 that institutions offering the 3+1-year (honours) programme migrate to a four-year professional degree.[22] the minister of health, following consultation with the hpcsa, intends to gazette changes to the regulations relating to the minimum standards of education, training, and examination in biokinetics, making the four-year professional bachelor’s degree mandatory.[23] institutions should allow undergraduate pipeline students to complete the academic pathway they embarked on. universities should inform prospective students of changes to the programme structure and selection criteria timeously. seven south african universities offered biokinetics programmes at the honours level in 2022 and six universities have already migrated to the new four-year degree. one university indicated that they would discontinue their honours programme in 2023 and will not develop the four-year programme. this means that there will be 12 institutions offering the programme in 2023, six on the old and six on the new programme. five institutions are migrating to the fouryear programme, whilst there is uncertainty about one institution’s plans. a consequence of the four-year programme is that the current one-year mandatory internship (after completion of the honours degree) will fall away. some scholars view this as an advantage of the new pedagogic model and programme structure, since clinical work-integrated learning will commence in the first study year and continue throughout the four-year period.[3] within the new model, the final clinical assessment will take place just before the students graduate, enabling immediate registration with the hpcsa and entering the workforce. in time, the hpcsa programme accreditation fig. 6. breakdown of hpcsa registered biokineticists by age, sex, and population group (2020) original research sajsm vol. 35 no.1 2023 6 panels would be ideally positioned to comment on the revised four-year curriculum and training and whether it delivers better qualified biokineticists. a community service year for graduates may further strengthen the roll-out of expertise in the public health sector. a disadvantage of the new model is that private practises may have become reliant on interns, and some may struggle without them. the financial sustainability of academic departments is also cause for concern because the new model may require an overhaul of the existing academic programme. departments may have to increase their intake of students to remain financially viable since the new programme structure, more teaching hours and supervision of students during clinical rotations, require extra human and financial resources. unfortunately, some programmes may be discontinued (e.g. the university of kwazulu-natal will not offer the biokinetics programme after 2022). in 2021, the basa president circulated a letter to the registrars and heads of departments of the various institutions. the president urged them to be cognisant of their enrolment numbers because there is pressure on private practices and sites where students complete their clinical training, warning that large graduate cohorts may lead to market saturation.[24] physical inactivity is the fourth leading risk factor for mortality worldwide.[25] regular physical activity can address several pathological conditions, thereby reducing population mortality and morbidity rates.[26] a strong body of evidence exists regarding scientifically-based exercise programmes for prevention and management of ncds and injuries.[27] this open access book chapter summarises empirical evidence on the efficacy of 50 south african biokinetics research publications in tackling the ncd epidemic. care-based health interventions aimed at improving physical activity are costeffective in high-risk groups, such as older persons and persons with heart failure.[28] extensive arguments have been raised for the expansion of biokinetics to the public sector in response to the increased prevalence of ncds [4,14,27,29] to alleviate some of the pressure on the public healthcare system by managing and preventing certain chronic, secondary, and associated conditions. physical activity is an affordable and safe alternative to chronic pharmacological and other medical strategies.[27] biokinetics was recently included in the department of health’s (doh) national obesity strategic policy.[30] basa also presented to the doh regarding inclusion and accreditation within the national health insurance (nhi) financing system.[30] biokineticists could also contribute to reducing rehospitalisation and over-reliance on the existing healthcare system by providing outpatient exercise rehabilitation services.[27] home-based physical activity programmes should table 2. academic programmes offered for biokineticists in south africa (2022) province university biokinetics programme (hpcsa registration) postgraduate programme name honours degree 4-year degree master’s studies doctoral studies 1 gauteng university of pretoria* bachelor of science honours in biokinetics yes no& yes yes 2 gauteng tshwane university of technology* bachelor of health sciences in biokinetics yes yes yes 3 gauteng university of johannesburg* bachelor of biokinetics yes yes yes 4 gauteng university of witwatersrand# bachelor of health sciences honours in biokinetics yes unknown yes yes 5 western cape stellenbosch university* bachelor of science honours in biokinetics yes no& yes yes 6 western cape university of cape town* bachelor of medical science honours in biokinetics yes no& yes yes 7 western cape university of the western cape* bachelor of science honours in biokinetics or bachelor of arts honours in biokinetics yes no& yes yes 8 kwazulu-natal university of kwazulunatal* bachelor of sport sciences honours in biokinetics yes+ no yes yes 9 kwazulu-natal university of zululand* bachelor of science honours in biokinetics yes no& yes yes 10 eastern cape nelson mandela university* bachelor of health sciences in biokinetics yes yes yes 11 free state university of the free state* bachelor of biokinetics yes yes yes 12 northwest north-west university* bachelor of health sciences in biokinetics yes yes yes 13 limpopo university of venda* bachelor of science in biokinetics yes no no * information verified by heads of departments and/or biokinetics programme coordinators. # unverified information collated from the university website. & universities currently developing/awaiting approval of the 4-year programme. + last intake of honours students in 2022 and will not offer the 4-year programme. original research 7 sajsm vol. 35 no.1 2023 aim to empower patients and their caregivers, promote quality of life, individual independence, and optimise reintegration into communities.[27] recommendations the current research sets the groundwork for future studies to develop plans for implementation at the tertiary education, private, and public health sector levels to ensure the profession’s long-term sustainability. the profession faces various socio-economic, socio-political, and sociodemographic challenges that should be explored and addressed critically. it is imperative that financial resources and research be strengthened. health economists should conduct feasibility studies to incorporate biokinetics into the public health sector. establishing the need for and viability of biokineticists in the public health sector should be prioritised. basa should lobby the health ministry to introduce statefunded provincial positions, like those for physiotherapy, and occupational therapy. the introduction of community service years may benefit society at large. clear guidelines should be imposed on how many students the accredited institutions may enrol, train, and deliver, because the new training model may put more pressure on existing private practices, due to the cancellation of the previously mandatory one-year internships. continuous monitoring and evaluation are needed to avoid market saturation. the profession’s workforce and human resource status (in both the private and public health sectors) should be monitored continuously and strengthened accordingly. the expertise of these healthcare specialists should be utilised to address chronic diseases of lifestyle, disabilities and orthopaedic injuries through clinical exercise therapy and promoting physical activity. conclusion based on the period under review (2000 to 2020), the biokinetics profession seems well established, healthy, and steadily growing in south africa. there are encouraging signs of international expansion. whilst the demographic profile of registered biokineticists has transformed steadily, the need to transform the profession to become nationally representative is still strong. women continue to dominate the profession. regarding training and education, the ongoing migration to four-year professional qualifications is more aligned with the academic requirement of other health professions, like physiotherapy and occupational therapy. there appears to be stability in the number of institutions that offer training and educational programmes, despite the transition to the new four-year pedagogic model and revised programme structure. there is optimism that the proposed nhi financing system would include the profession of biokinetics. expansion into the public health sector should be the profession’s primary focus. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: rt: conceptualised the study, retrieved, analysed, visualised, and interpreted the data, drafted the first manuscript, and approved all submissions. hg: co-designed the study, provided critical review, added training and education-related content to the first draft, submitted the manuscript and made revisions. cv: co-designed the study, added biokinetics-related content throughout the review process, and approved all submissions. uc: conceptualised and co-designed, provided critical review, and approved all submissions. references 1. cleophas fj. a political-institutional history of the stellenbosch university physical education department, 1936–1939. sport soc 2021; 1–14. 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[doi: 10.7196/ajhpe.2021.v13i1.1287] 30. basa annual general meeting. basa president’s address at the international festival of sports, exercise & medicine conference in pretoria, south africa. 1 october 2022. https://doi.org/10.1111/jep.13502 https://doi.org/10.1080/02589000701782612 https://doi.org/10.1080%2f14034940600627853 original research 51 sajsm vol. 28 no. 2 2016 the relationships between rugby ground pass accuracy and kinematic variables resulting from two different pelvic orientations a green,1 phd, s kerr,1 phd, b olivier,2 phd, c dafkin,1 msc, w mckinon,1 phd 1 school of physiology, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 department of physiotherapy, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: a green (andrew.green@students.wits.ac.za) all rugby players are required to be proficient at passing the ball (unlike specialist areas distinct to rugby such as the scrum and lineout), variation in passing ability among playing positions has been reported [1]. current research has highlighted the effect of hand dominance on the rugby pass, both maximally [2] and over various set distances [3]. recent studies have shown that training is known to influence passing dynamics [4] and that caffeine supplementation does not influence passing accuracy [5]. interestingly, these studies have looked exclusively at the running pass. another passing type in rugby is the pass from the ground. when a scrum or breakdown occurs the ball is placed on the ground where the arriving player will attempt to distribute the ball to another advancing player. the ground pass is made from a comparatively static position, when compared to the running pass. regarding the technical attributes of the ground pass there are two different strategies that are commonly employed: 1) a technique that predominantly uses the arms; or 2) a technique that predominantly uses rotations of the shoulder and pelvic girdles. the optimal passing sequence should involve both rotation of the torso and pelvis and the extension of the arms, resulting in an accurate pass. the purpose of this study was therefore to primarily assess whether biomechanical correlates of the rugby ground pass accuracy exist in high-level amateur rugby players. additionally, the study aims to assess the effects of the two passing strategies and their resulting accuracies. it was hypothesised that passing accuracy may be related to the upper body kinematics of the players, specifically the rotations of the torso and pelvic girdles along with additional contributions from the arms. methods participants sixteen first team university level rugby players (11 backs, 5 forwards) that volunteered for this study had an average age of 22±2 years; height of 1.77±0.04 m and body mass of 86.8±16.8 kg. ethical approval was granted by the university ethics committee (m131019) and written informed consent was received prior to the start of testing. all participants were right-handed and injury-free at the time of the study. the participants were required to pass from a distance of 10 m towards a target within a larger calibrated frame. the calibration frame consisted of a 2 m×2 m metal frame with a middle portion consisting of a rectangular target defined by the vertical limits in-between 0.74 m and 1.77 m from the ground. the horizontal width of the target was the length of a regulation rugby union ball (0.33 m). the vertical limits were based on data collected from 27 players, when asked what constituted the limits of a catchable pass while running on attack during a game. pass accuracy was quantified as the distance of the ball position from the central point of the accurate zone. digital video images were recorded (sony dcr-sx41, sony corporation, tokyo, japan) and the position of the ball as it reached the frame was digitally identified using image analysis tools (matlab 7, mathworks, natick, usa). full-body kinematics were recorded using an 18 camera system recording at 100 hz (optitrack flex:v100r2, natural point inc., corvallis, oregon, usa). a measurement volume of approximately 18m3 was calibrated (amass, c-motion germantown, maryland, usa) in the area where ball release would occur, to a level of sub-millimetre error. custom written algorithms were used to analyse body positions as derived from raw marker location data in matlab 7. the various kinematic variables were measured based on descriptions outlined table 1. passing kinematics were analysed at the moment of ball release. two distinct passing groups were identified (fig. 1): one group with a pelvic rotation angle of greater than 80 ° between the direction of the target and the pelvic vector introduction: despite having been largely understudied, one of the crucial components of a team’s success in rugby is accurate passing. this study identified biomechanical correlates of the rugby ground pass and accuracy performance. methods: sixteen club players (height 1.77±0.04 m; mass 86.8±16.8 kg) undertook a combined total of 96 passes and their respective body kinematics were analysed concurrent with measurements of pass accuracy at 10 m. two distinct types of body orientations were found to be utilised by the players: a side-on orientation (pelvic rotation >80 °) and a front-on orientation (pelvic rotation <80 °). results: side-on body orientation passes were more accurate than front-on body orientation passes (p<0.0001). fair relationships were present between the pass accuracy and upper body and hip kinematics for the two distinct body orientations individually. however, no common relationships were observed between the different orientations. conclusion: therefore different strategies exist within players to perform the ground pass with varying grades of accuracy. keywords: biomechanics, direct measurement s afr j sports med 2016;28(2):51-54. doi: 10.17159/2078-516x/2016/v28i2a421 http://dx.doi.org/10.17159/2078-516x/2016/v28i2a421 original research sajsm vol. 28 no. 2 2016 52 fig. 1. defining the two body orientations, by the pelvic positions at ball release. a. front-on orientation (pelvic rotation angle less than 80 ° relative to the direction of the target). b. side-on orientation (pelvic rotation angle greater than 80 ° relative to the direction of the target). (side-on orientation) and one with a pelvic rotation angle of less than 80 ° between the direction of the target and the pelvic vector (front-on orientation). the corresponding side of the participant’s body to that of the intended pass direction will be considered as the pass side, and the opposite side will be considered the stance side. procedure participants underwent a self-guided warm-up prior to testing. all participants were allowed no more than five practise passes under the experimental conditions. all participants performed in a randomised order a total of six passes (three to the left, and three to the right) using a set of standardised training rugby union balls (gilbert xt300, grays of cambridge (int) ltd, east sussex, united kingdom). participants were instructed to pass legally (backwards or lateral) towards the target with the aim of achieving an accurate pass. statistical analysis all data distributions were analysed using a shapiro wilk normality test. passing accuracy error distance is represented as median: range (between quartile 1 and quartile 3) due to the non-normal distribution. accordingly, a mann-whitney test was used to compare accuracy differences between the two passing orientation types. all kinematic data are represented as mean±standard deviation. spearman’s correlations were performed between the pass accuracy error distance and the kinematic variables at ball release in matlab 7. a significance level of p<0.05 was applied. positive values indicate that a greater kinematic variable would result in less accurate passes (larger error). negative correlations indicate that a greater kinematic variable would result in more accurate passes (smaller error). results the passing accuracy error was not significantly (p=0.945) different between the right direction (20.0 cm: 8.4-44.9 cm) and the left direction (20.9 cm: 9.1-43.8 cm). the pass accuracy error distances were significantly larger (p<0.0001) for the front-on body orientation (34.1 cm: 12.9-49.1 cm) (n=64) compared to the side orientation 8.8 cm: 4.4-20.3 cm) (n=32). playing positions and individual passing accuracies are reported in table 2. additionally, table 2 shows that only four participants used a single body orientation (3 front-on; 1 side-on) for their six passes. leaving the remaining 12 participants with a combination of the two body orientations used during the pass. correlations between body kinematics and the pass accuracy distances, and their qualitative descriptions, are reported in table 3. table 1. definitions of the kinematic variables kinematic variable definition neck flexion calculated as the angle of flexion between the upper thorax and head head rotation* calculated as the difference between the global horizontal vector and the horizontal component of the head segment torso rotation* calculated as the difference between the global horizontal vector and the horizontal component of the torso pelvic rotation* calculated as the difference between the global horizontal vector and the horizontal component of the pelvis x-factor defined as the difference between torso and pelvic rotations back flexion calculated as the angle between the lower back (sacrum to tenth thoracic) vector and upper back (tenth thoracic to seventh cervical) vector lateral bend angle defined as the angle of abduction of the torso sagittal plane relative to the pelvic sagittal plane elbow flexion calculated bilaterally, as the angle of flexion between the humerus vector and the vector of the forearm wrist flexion calculated bilaterally, as the angle of flexion between the forearm vector and the vector of the hand knee flexion calculated bilaterally, as the angle of flexion between femur vector and the vector of the shank ankle flexion calculated bilaterally, as the angle of flexion between the vector of the shank and the foot * a rotation value of less than 80 ° would indicate an open stance with the body facing the target. a value larger than 80 ° would indicate that the body would be parallel to the target direction. original research 53 sajsm vol. 28 no. 2 2016 discussion unlike previous studies that investigated the running pass in rugby players [1-5], the current study aimed to assess kinematic strategies and accuracy performance of the rugby union ground pass. it was noted that two distinct types of body orientations were utilised by the players. these two distinct types of body orientations resulted in differences in accuracy performance and kinematic correlations to passing accuracy. table 2. playing positions and individual assessment of passing orientation frequency, median and inter-quartile range participant playing position front-on/ side-on accuracy median (cm) accuracy quartile 1 (cm) accuracy quartile 3 (cm) 1 scrum half 3/3 40.9 34.9 49.7 2 scrum half 6/0 18.1 12.9 32.4 3 flank 5/1 34.0 21.1 39.6 4 wing 3/3 9.4 8.7 13.0 5 prop 6/0 8.5 7.0 9.9 6 hooker 0/6 26.9 24.3 28.9 7 wing 6/0 4.9 3.9 5.2 8 number 8 3/3 5.8 5.3 8.4 9 fly half 3/3 4.6 3.0 5.8 10 fullback 5/1 43.1 30.6 45.4 11 fly half 5/1 15.4 10.1 20.3 12 prop 5/1 39.1 31.0 44.9 13 wing 3/3 39.7 14.1 103.5 14 centre 3/3 62.0 57.2 98.3 15 centre 5/1 44.8 36.6 49.1 16 scrum half 3/3 29.0 18.3 45.2 combined 64/32 21.0 9.2 44.6 table 3. kinematic joint angular data and spearman’s rank correlation coefficients for kinematic variables and their relationships to the pass accuracy error distance for front and side body orientations. front body orientation (n=64) side body orientation (n=32) kinematic angle (°) spearman's r qualitative descriptions † kinematic angle (°) spearman's r qualitative descriptions † neck flexion 100.2±13.4 0.124 little 99.3±15.6 -0.458* fair head rotation 88.4±9.5 0.382* fair 88.6±7.4 -0.154 little torso rotation 32.4±18.6 -0.189 little 143.1±39.4 0.122 little lateral bend 15.9±8.1 0.002 little 16.9±7.9 0.269 fair back flexion 15.7±8.2 0.204 little 17.9±4.0 -0.027 little stance side elbow 68.1±18.7 -0.258 fair 66.0±15.3 0.655* moderate pass side elbow 50.2±17.6 -0.331* fair 52.9±12.6 0.013 little stance side wrist 149.1±15.6 -0.210 little 150.0±13.0 -0.457* fair pass side wrist 127.2±22.7 0.134 little 130.6±17.8 -0.464* fair pelvic rotation 35.8±14.6 -0.105 little 133.8±33.2 -0.182 little x-factor -2.7±12.7 -0.380* fair 6.7±14.8 0.140 little stance side knee 58.1±27.5 0.050 little 57.0±19.9 -0.255 fair pass side knee 53.6±28.3 0.055 little 53.5±24.0 -0.095 little stance side ankle 75.2±16.4 0.096 little 81.4±19.1 0.253 fair pass side ankle 65.4±8.8 0.111 little 64.5±6.0 -0.118 little † qualitative descriptions for the strength of the relationships were defined as portney and watkins [6]: r=0.00-0.25 little or no relationship; r=0.25-0.50 fair relationship; r=0.50-0.75 moderate to good relationship; r>0.75 good to excellent relationship. * p<0.05 spearman’s rank correlation coefficient original research sajsm vol. 28 no. 2 2016 54 firstly, it must be noted that there was no significant difference between the passes directed to the right and the passes directed to the left. this is contrary to studies presented by pavely et al.[2] worsfold and page[3] and sayers and ballon[7]. these studies reported the effects of hand dominance on maximal pass distance, various pass distances and pass velocity, respectively. the lack of difference in passing accuracy based on hand dominance resulted in the combined accuracies of the passes being used. from this analysis it was noted that two distinct body orientations were used to execute the passes: front-on and side-on. however, only four of the 16 participants used a single body orientation to execute all of their six passes. the remaining 12 participants all used a combination of front-on and sideon body orientations. the significant correlations highlight interesting relationships between the body movements and pass accuracy independent of the two distinct body orientations. isolating the front-on body orientation, the positive correlation for accuracy and head rotation would suggest the importance of identifying the target in executing an accurate pass. furthermore, the front-on body orientation requires a greater extension of the pass side elbow, while the side-on body orientation requires the stance elbow flexion to be larger to achieve accurate passes. a significant correlation between the velocity of the stance side elbow flexion and the resulting pass velocity has been reported [7]. consequently, the stance side elbow may be essential to the performance of the pass. interestingly, the passes were more accurate with decreasing values of x-factor. this would suggest a greater torso rotation relative to the pelvic rotation is needed to achieve an accurate pass. regarding the side-on body orientation relationships: pass accuracy requires more neck extension and bilateral wrist flexion, as indicated by the significant correlations. these results may indicate that in this body orientation, the players would need to elevate their heads to observe and identify the target by reducing the degree of neck flexion (increased neck extension). the relationships shown for the pass accuracy and the different body orientations highlight the potentially different strategies that are used to achieve an accurate pass. interestingly, there were no common kinematic variables that were significantly correlated to accuracy between the two different body orientations. it would appear that in the side-on orientation the players would rely on the arms, specifically the stance elbow flexion, head flexion, stance side wrist flexion and pass side wrist flexion. while the front-on body orientation utilises head rotation, pass side elbow flexion and x-factor (torso and pelvic girdle separation) to achieve accurate passes. while these relationships do give some insight into the different strategies used in the two distinct pass styles, they do not definitively identify all the parameters used by the players. furthermore, they merely identify fair relationships between the parameters and do not imply causation. further investigation, specifically into the muscular activity, is required to conclusively answer this. ultimately, the passing type used by the players should not affect the gameplay provided they are able to achieve an accurate pass. the data within the current study would suggest that the side-on pass orientation was shown to be more accurate than the front-on pass. however, the accuracy constraints in the current study do not take into account any movement of the receiving player, with the vast majority of passes likely to be caught by the receiving player. additional limitations include: the small sample size; playing level of the participants; and the limited number of passes performed by each player. future studies are warranted to investigate the duration of the passes and the effects of playing position on the body orientations used to perform the passes. conclusion the current study has identified two different kinematic passing strategies used by players to achieve different levels of pass accuracy. specifically, the side-on body orientation produced more accurate passes than the front-on body orientation. coaches should train ground passing strategies that result in the most accurate outcomes. the majority of ground passes performed by a sample of rugby players of various positions resulted in a front-on body orientation. however, when a side-on pass orientation was used, the passes were significantly more accurate. passing strategies may be reliant on the orientation of the body relative to the target. take home message ground passing accuracies were not subject to the effect of hand dominance over 10 m. passing accuracies may be reliant on the body orientations used during the passing sequence and fair-to-moderate relationships exist between passing accuracy and kinematic variables. training regimes that enhance these kinematic variables may be beneficial to improving passing accuracy. references 1. gabbett t, kelly j, pezet t. a comparison of fitness and skill among playing positions in sub-elite rugby league players. j sci med sport 2008;11(6):585-592. [http://dx.doi.org/10.1016/j.jsams.2007.07.004] 2. pavely s, adams rd, di francesco ti, et al. execution and outcome differences between passes to the left and right made by first-grade rugby union players. phys ther sport 2009;10(4):136-141. [http://dx.doi.org/10.1016/j.ptsp.2009.05.006] 3. worsfold pr, page m. the influences of rugby spin pass technique on movement time, ball velocity and passing accuracy. int j perform anal sport 2014;14(1):296-306. http://www.ingentaconnect.com/content/uwic/ujpa/2014/00000014/0 0000001/art00026 4. hooper jj, james sd, jones dc, et al.. the influence of training with heavy rugby balls on selected spin pass variables in youth rugby union players. j sci med sports 2008;11(2): 209-213. [http://dx.doi.org/10.1016/j.jsams.2006.09.005] 5. assi hn, bottoms l. the effects of caffeine on rugby passing accuracy while performing the reactive agility test. sci sport 2014;29(5):275-281. [http://dx.doi.org/10.1016/j.scispo.2014.07.012] 6. portney lg, watkins mp. (2009). foundations of clinical research: applications to practice. 3rd ed.. london: pearson prentice hall. 7. sayers m, ballon r. biomechanical analysis of a rugby pass from the ground. 7th world congress of science and football, nagoya, japan 26-30 may 2011. original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license physical activity and quality of life of patients with fibromyalgia l smith, mphil (biokinetics); m croucamp, bbio department of sport and movement studies in the faculty of health sciences, university of johannesburg, doornfontein campus, johannesburg, south africa corresponding author: l smith (lynnvr@uj.ac.za) fibromyalgia syndrome (fms) is a chronic disorder characterised by musculoskeletal pain and a heightened response to the sensation of pressure.[1,2] the condition is more prevalent in the adult female population and is influenced by socioeconomic and cultural factors.[3] from a healthcare perspective, many patients report inconsistencies within the healthcare system and poorly coordinated care due to the complexity of the illness.[4] in addition, healthcare practitioners are of the perception that fms is not a real medical condition, which often results in debates and challenging encounters between healthcare practitioners and patients.[4] an exploratory study reported a patient stating the following: ‘one day i walked into the [doctors’] rooms, [and] he told me once again ‘there’s nothing wrong with you’, and i told him ‘but doctor, this is impossible. i can’t sleep, i can’t turn, i can’t get up from the bed. i have difficulty driving’. [1] on the other hand, a large proportion of fms patients in south africa are disadvantaged by limited access to healthcare facilities, healthcare staff and treatment owing to the disadvantaged communities they reside in.[1] although a multidisciplinary and biopsychosocial approach to fms has been advocated for, there is still a need to increase awareness.[2] of the numerous methods identified to manage the illness, such as relaxation exercise, social support, medication, and prayer, to name a few, exercise has been proven to be the most successful among fms patients.[5] despite the efficacy of exercise in slowing down the progression of fms and the management of its symptoms, many patients are still not engaging in regular physical activity.[5] the effects of physical activity on fms and overall quality of life (qol) have been well-documented. several studies comparing the effects of aerobic exercise and muscle strengthening programmes among patients with fms have yielded benefits with fatigue, sleep, tender point count, pain, fitness and qol.[6] interestingly, 12 weeks after exercise had been stopped among patients, those who had previously engaged in muscle-strengthening activities experienced a reoccurrence of symptoms, while the benefits of aerobic exercise lasted for a longer period of time.[6] in terms of aerobic activities, aquatic exercise and land-based exercise showed similar improvements in the physical and mental health in this population; however, programmes that combine stretching, aerobic and muscle strengthening activities are the most effective in improving the qol and the overall well-being of patients with fms.[6] regardless of the debates relating to the most suitable mode or intensity of exercise for fms patients, physical activity in any form has been shown to improve qol in these patients.[7] however, physical inactivity in south africa is a major concern as the country has the highest prevalence of inactivity compared to other countries, such as developing countries like poland and romania.[8] in conjunction with increasing physical activity, there is also a need to emphasise a decrease in sedentary time for optimal benefit.[9] for this reason, the purpose of this research in determining physical activity levels and qol amongst fms patients in the johannesburg region was established. methods study design and participants this study used a cross-sectional research design. descriptive and quantitative data were collected to achieve the aims and objectives. a total of 38 participants from the johannesburg region diagnosed with fms formed the sample population of this pilot study. participants of both genders who have been diagnosed with fms by a qualified physician were recruited. the inclusion criteria were participants between the ages of 18 and 65 years diagnosed with fms and who have access to the internet to complete the online questionnaire. ethical considerations this research was approved by the institution’s research ethics committee (rec-229-2019). principles of autonomy, background: fibromyalgia syndrome (fms) has been linked to decreased social functioning, poor mental health, and quality of life (qol). increased physical functioning and activity can result in improvements in social, mental and overall health, as well as lowered depression and anxiety levels. objectives: the aim of this study was to determine physical activity levels and qol amongst patients diagnosed with fibromyalgia in the johannesburg region of south africa. methods: the research design was cross-sectional. descriptive and quantitative data were collected. fms patients (n=38) completed an online questionnaire on the google forms platform. the questionnaire was comprised of four components, namely demographics, the global physical activity questionnaire (gpaq), the fibromyalgia impact questionnaire (fiqr), and the short form-36 (sf-36). during data analysis, descriptive characteristics and correlations were computed. the significance level was set at p ≤ 0.05. results: results revealed high fiqr scores (67%) accompanied with low qol scores (<50% in all domains). there was no correlation between physical activity and fiqr, and physical activity and qol. conclusion: high scores on the impact of fms were associated with lower overall qol scores. however, the relationship between physical activity, and the impact of fms and qol remain inconclusive. keywords: fibromyalgia syndrome, fms, exercise, fibromyalgia impact s afr j sports med 2023;35:1-6. doi: 10.17159/2078-516x/2023/v35i1a14781 mailto:lynnvr@uj.ac.za http://dx.doi.org/10.17159/2078-516x/2023/v35i1a14781 https://orcid.org/0000-0001-6728-4704 https://orcid.org/0000-0002-8562-5004 original research sajsm vol. 35 no.1 2023 2 beneficence, non-maleficence, and justice were applied and adhered to throughout the research process. sampling and recruitment researchers contacted rheumatologists and general practitioners and requested referrals of their patients who have been diagnosed with fms. once participants had been contacted and agreed to participate in the research, they were asked to refer other qualifying patients by means of snowball sampling. all participants who met the inclusion criteria and completed the questionnaire formed part of the study’s sample. data collection the three questionnaires used in this study were collated and uploaded onto the google forms platform (appendix a). a link to the online questionnaire was distributed to the referred participants via email. once accessed, the duration given to complete the questionnaire was 20 to 30 minutes. measuring tools and instruments the online version of this questionnaire was a combination of three questionnaires, namely, the fibromyalgia impact questionnaire – revised (fiqr), the sf-36, and the global physical activity questionnaire (gpaq). in addition, a demographics section was included at the beginning of the questionnaire with the purpose of defining the characteristics of the sample population. statistical analysis data were computed on the statistical package for social sciences (spss) for windows version 15.0 (spss inc., chicago, il, usa). together with descriptive statistics, inferential statistics were also computed. for the purpose of determining normality, the shapiro-wilk test was given. pearson’s correlation coefficient was used to establish the relationship between variables. the level of significance was set at 5% (p ≤ 0.05). the bonferroni adjustment was applied as a post hoc test and was set at p ≤ 0.0167. this was computed to account for the multiple comparisons between variables and to avoid false statistical inferences.[10] results the results presented in this section include the demographics of the sample, physical activity levels (assessed by the gpaq), the impact of fms on daily life (assessed by the fiqr), qol, relationships between qol table 1. demographic data of the participants (n=38) domain frequency (%) gender female 37 (97.4) male 1 (2.6) age 18-20 1 (2.6) 21-30 4 (10.5) 3140 6 (15.8) 41-50 12 (31.6) 51-60 11 (29.0) >60 4 (10.5) ethnicity caucasian 26 (68.5) asian / pacific islander 4 (10.5) mixed ethnicity 4 (10.5) indian 4 (10.5) black african 0 (0.0) employment status employed full time 16 (42.0) unable to work 6 (15.8) unemployed but not currently looking for work 5 (13.2) self-employed 5 (13.2) employed part time 2 (5.3) retired 2 (5.3) unemployed and looking for work 1 (2.6) student 1 (2.6) 0 10 20 30 40 50 60 70 80 90 w al ki ng o th er sw im m in g y og a p ila te s r un ni ng /j og gi ng w ei gh t lif ti ng d an ci ng b ox in g c yc lin g t ai c hi p e r c e n t a g e ( % ) physical activity type fig. 1. various activities performed by participants (%) (n=31). participants could select multiple responses. original research 3 sajsm vol. 35 no.1 2023 and fms impact, results of the gpaq in relation to total time spent being physically active, total time spent being sedentary and relationships between active time, sedentary time, fms impact and qol. sociodemographic aspects table 1 reflects the demographic data of the sample. of the 38 participants who completed the online questionnaire, 37 were females (97%) and 1 was male (2.6%) (table 1). the dominant age grouping for fms in this sample was 41 to 50 years, as 32% of the participants were aged in this range. only one participant (2.6%) was aged between 18 and 20 years. majority of the participants (68%) were caucasian, and no participants were of black african descent. a large proportion of the sample (42%) indicated full-time employment, while 16% of the participants were unable to work. physical activity the various activities performed by participants who engage in exercise are illustrated in figure 1. a total of 31 participants (82%) indicated that they currently engage in physical activity (figure 1). participants could select multiple responses to this question, resulting in the total exceeding 100%. the most popular type of physical activity was walking (79%), while none of the participants indicated participation in tai chi. participants stated that they spend an average of 903 minutes (15.1 hours) a week engaged in some sort of physical activity. total sedentary time on average was reported as 5.8 hours a week. the impact of fms on daily life (fiqr) the impact that fms has on the daily life of patients with fms is demonstrated in table 2. table 2 shows that fms was shown to have a large impact on the participants’ daily lives, reflected as a mean total fiqr score of 67%. the higher the fiqr score, the larger the impact it has on the participant’s life. quality of life (sf-36) table 3 reflects the qol scores across eight domains. the scores for all qol domains were below 50%, indicating a low score (table 3). role limitations due to physical health (15%), role limitations due to emotional health (22%) and energy/vitality (22%) exhibited the lowest scores, while social functioning yielded the highest mean score (40%), although it was also below 50%. the relationship between fiqr and sf-36 the correlations between fiqr and qol are depicted in table 4. although all domains reflected a significant relation with qol, table 2. impact of fms on daily life (fiqr) (n=38) domain score (%) daily function 18.4 ± 5.7 pain levels 13.4 ± 4.4 symptoms experienced 35.5 ± 7.2 total fiqr score 67.4 ± 16.1 data are expressed as mean ± sd. the higher the score, the larger the impact on the participants life. fiqr, fibromyalgia impact questionnaire – revised; fms, fibromyalgia syndrome. table 3. quality of life of participants (sf-36) (n=38) domain score (%) physical functioning 34.9 ± 21.9 role physical 15.1 ± 25.0 role emotional 22.8 ± 33.9 energy/fatigue 22.2 ± 14.4 emotional wellbeing 44.8 ± 18.4 social functioning 39.8 ± 23.8 pain 30.9 ± 20.9 general health 32.6 ± 18.8 data are expressed as mean ± sd. table 4. correlation between fiqr and qol (n=38) domain pearson correlation (95% ci) physical functioning -0.69 (-0.82, -0.46) role physical -0.53 (-0.73, -0.24) role emotional -0.51 (-0.71, -0.22) energy/fatigue -0.71 (-0.84, -0.50) emotional wellbeing -0.72 (-0.84, -0.52) social functioning -0.70 (-0.84, -0.49) pain -0.71 (-0.84, -0.50) general health -0.55 (-0.74, -0.27) all data shown are significant at the level of p <0.01 (after bonferroni adjustment). fiqr, fibromyalgia impact questionnaire – revised; qol, quality of life table 5. correlation between total active time, sedentary time and qol (n=38) total active time sedentary time domain pearson correlation (95% ci) p value pearson correlation (95% ci) p value physical functioning 0.39 (0.08, 0.63) 0.016 0.09 (-0.24, 0.40) 0.604 role physical 0.19 (-0.14, 0.48) 0.266 0.19 (-0.14, 0.48) 0.266 role emotional 0.05 (-0.28, 0.36) 0.782 0.03 (-0.29, 0.35) 0.852 energy/fatigue 0.33 (0.01, 0.58) 0.047 0.09 (-0.23, 0.40) 0.580 emotional wellbeing 0.16 (-0.17, 0.45) 0.350 0.11 (-0.22, 0.41) 0.523 social functioning 0.05 (-0.28, 0.36) 0.774 0.25 (-0.08, 0.53) 0.130 pain 0.13 (-0.19, 0.44) 0.422 0.01 (-0.32, 0.33) 0.974 general health 0.29 (-0.03, 0.56) 0.079 0.01 (-0.33, 0.32) 0.973 qol, quality of life. original research sajsm vol. 35 no.1 2023 4 the most significant correlation exists between fiqr and emotional wellbeing and the weakest correlation exists between the fiqr and role limitations due to emotional health (table 4). relationship between total time active, sedentary time and sf-36 table 5 shows the correlations between total active time, sedentary time and qol of the sample. table 5 illustrates that neither of the domains in qol showed a statistically significant correlation total active time and sedentary time. discussion this study aimed to determine the qol amongst patients with fms by defining physical activity levels and the impact of fms. demographic aspects the majority of the sample consisted of females, namely 97%. similarly, research shows that fms is more prevalent in the female population, with a ratio of 6:1 to their male counterparts.[3,11] a study assessing the qol amongst fms patients yielded similar findings, with a 95% prevalence of females in the sample.[12] the majority of the sample (71%) were over the age of 41 years, which is line with what is contained in the literature, indicating a higher prevalence in middle-aged patients (30-50 years), or older.[12] other studies evaluating pain and qol amongst patients with fms consisted patients with a mean age of 46 and 50 years, respectively, in their samples.[12] an international study in america found that 91% of their sample were of caucasian ethnicity.[13] this is similar to the findings in this research study, where the majority (68%) of the sample was caucasian. in contrast, another international study concluded that individuals from african descent were 1.52 times more likely to be diagnosed with fms in comparison to their caucasian counterparts.[14] therefore, definite conclusions with regards to the influence of ethnicity on fms cannot be shown. in this study, 61% of participants were employed either on a fulltime or part-time basis, or were self-employed. although 16% were unable to work, it was unclear whether this was owing to their fms, as reasons for unemployment was not assessed in this questionnaire. in a study conducted in 2021, the majority of the sample (52%) were employed while living with fms, although 6% were on long-term sick leave due to their fms symptoms.[12] the impact of fms on daily life the overall impact of fms on the life of the participants in this study was high (67±16%). symptoms experienced had a large impact on daily life, while pain and daily function had a smaller impact. previous studies reported similar results.[15] owing to the subjective nature of the questionnaires, it is evident that the participants in this study deemed their symptoms to affect their daily lives more than their physical limitations and pain. in addition, a recent study reported that pain is not the major predictor and contributor to quality of life amongst fms patients.[16] this notion is supported by previous research, which determined that tiredness and a depressed mood affected fms participants more than their pain levels experienced.[17] in a study examining the experiences of south african fms patients, one participant reported; “the symptoms really started to become quite difficult … when i used to go to doctors saying… because at that point i was still physically very active … ‘this fatigue is unmanageable. i can’t cope with the fatigue’.”[18] another study reported that poor sleep quality and sleep disturbances were the most frequently reported complaints.[12] this could not only be linked to fatigue, but by identifying subgroups of patients with similar experiences and symptoms, healthcare practitioners can improve the diagnostic criteria and treatment of the fms.[12] quality of life the low overall qol (<50%) in this study correlates with previous research showing that the qol of fms individuals is extremely low.[19] the participants in this research study had low scores for vitality and pain. in addition, the same participants who reported low scores for vitality and pain, also required attention in the role limitations due to physical health and emotional problems. similarly, a study done outside of south africa indicated that participants yielded low scores in the mental health, social functioning, vitality, pain and general health categories.[19] in another study, the areas with the lowest qol scores included depression, general activity, general health perception, and vitality.[16] it has been reported, however, that depression is a strong predictor of qol and that depression and anxiety often mediate the effect of pain on overall qol.[20] physical activity, sedentary time and fms contrary to previous research, 82% of participants in this study stated that they participated in some form of physical activity. in other research, the majority of individuals with fms do not typically participate in physical activity and are classified as aerobically unfit. [21] participants in this study reported that they spent a higher than usual amount of time engaging in some form of physical activity during the week. this included activity as part of work, travel to and from work, as well as recreational physical activity. it is possible that the participants were not fully able to differentiate between the different intensities of activity, leading to unusually high activity times shown. this could be reflected in the large amount of time spent being sedentary per day. high sedentary time has been associated with worse pain regulation, overall pain, fatigue, and disease impact in fms patients.[9] it has also been determined that substituting 30 minutes of sedentary time with light physical activity yielded better scores in the bodily pain, vitality and the social functioning domains of the sf-36, while all domains of the fiqr showed improvements. [9] although sedentary time has been linked to increased pain, it has been postulated that pain does not play a role in physical activity participation amongst these patients. while research has shown that 60% to 80% of fms patients believe physical activity to be beneficial for weight loss, fitness, and feelings of wellbeing, they reported that it was ineffective in reducing pain.[22] the original research 5 sajsm vol. 35 no.1 2023 perception of its ineffectiveness in reducing pain could be a barrier to the increase in physical activity, or the patient’s willingness to continue to adhere to an exercise programme. previous research has shown a correlation between low sedentary time and high activity time to improved symptomology in fms patients, as well as higher qol.[15,7] due to the nature of the pilot study and the small sample size, the results of this study are inconclusive. however, it has been postulated that better qol was common amongst those patients whose adherence to treatment is higher.[12] for this reason, the researchers believe that if this study is replicated amongst a larger sample, findings would illustrate that higher physical activity levels and reduced sedentary time are linked to improved qol and lower fms impact. the relationship between qol and impact of fms the last objective of this study was to determine the relationship between fms and qol. findings illustrated that a strong correlation exists between fiqr and sf-36 in all domains. high fiqr scores were associated with low scores on the sf-36, indicating that the high impact of fms experienced by the sample in daily life points toward a lower the qol for the participant. this was especially true in the relationship to pain, where high pain levels resulted in poorer qol. pain in fms is treated with pharmacology and physical therapy.[23] while it has been said that some medications produce side effects severe enough to result in patients discontinuing, adherence to physical therapy, although beneficial, is also low due to pain tolerance and the willingness to participate. [23] management of the condition should include a multidisciplinary approach, by integrating complementary medicine and non-pharmacological interventions to reduce pain, increase physical activity and improve qol. [23] a study conducted in france also reported that their sample reported high impact scores and low qol scores. [12] their sample had shown deterioration in functional autonomy, increased severity of symptoms and emotional distress, as well as poor overall qol. [12] this led to the researchers advocating for increased awareness and a call to healthcare practitioners to pay special attention to fms patients, as a large majority tend to distrust the healthcare system, resulting in poorer adherence to medical treatment. [12] limitations the generalisability of the findings in this study should be considered owing to the sample being recruited from the johannesburg region only. ethnicities in the demographic section of the questionnaire were not applicable to the south african context, which could have made it challenging for participants to place themselves in this section. the different intensities used in the gpaq were not clearly defined. participants may not have been able to clearly differentiate between the different intensities, leading to inaccurate recording of weekly activities. whether the participants were taking medications or receiving any form of treatment for their fms was not assessed, which could have a significant impact on results of this study. the covid-19 pandemic and the south african lockdown resulted in the questionnaire being placed online and prevented its physical administration, which may have had an impact on the sample size. this study did not assess the past and current treatment plans of the participants and how they might have influenced the results. it is possible that the participants are using only exercise as a treatment for the condition, as opposed to a multidisciplinary and holistic approach. this could possibly explain the positive relationship between qol and exercise in the present study. the body mass index was not assessed in this study, which could play a role in the fiqr and qol scores. it is thus possible that the majority of participants in this study are overweight, which would influence the results. conclusion the findings in this study have demonstrated a large impact of daily life in south african fms patients. it is also evident that these individuals have a low qol, although participation in physical activity is evident. however, the link between exercise and qol of these individuals is unclear. it is suggested that this study be repeated with a larger sample size to determine a clear link between physical activity and qol amongst patients with fms in south africa. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: both authors provided a substantial contribution to: (i) the conception, design, analysis and interpretation of data; (ii) drafting or critical revision for important intellectual content; and (iii) approval of the version to be published. references 1. cooper s, gilbert l. an exploratory study of the experience of fibromyalgia diagnosis in south africa. health (london) 2017;21(3):337-353. 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[https://doi.org/10.1093/pm/pnaa329] https://doi.org/10.1007/s10067-007-0756-1 sajsm vol. 27 no. 4 2015 93 original research j t pearson,1 bsc (med) (hons) (exerc sci) (biokinetics); e d watson,2,3 mspsc; e v lambert,1 phd; l k micklesfield,2 phd 1 division of exercise science & sports medicine, department of human biology, faculty of health sciences, university of cape town, south africa 2 mrc/wits developmental pathways for health research unit, department of paediatrics, faculty of health sciences, university of the witwatersrand, johannesburg, africa 3 centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of witwatersrand, johannesburg, south africa corresponding author: l k micklesfield (lisa.micklesfield@uct.ac.za) background. a woman’s health status prior to, and during, pregnancy has been shown to influence maternal and foetal health outcomes, and therefore healthy behaviours should be encouraged to optimise weight gain during pregnancy. discussion. pre-gravid overweight and obesity, and excessive weight gain during pregnancy, are associated with several adverse pregnancy outcomes for the mother and the foetus. despite the fact that physical activity during pregnancy reduces the risk of excessive gestational weight gain, physical activity levels typically decline during pregnancy. several factors have been shown to influence physical activity during pregnancy, and preliminary data is available on identifying these factors in south african women. conclusion. very little is known about physical activity patterns in pregnant south african women in whom overweight and obesity is prevalent. examining these patterns, as well as the barriers and facilitators of physical activity in this population will assist in informing future interventions. keywords. south africa, obesity, barriers, interventions s afr j sports med 2015;27(4):93-96. doi:10.17159/2078-516x/2015/ v27i4a440 in south africa (sa), as the population undergoes economic transition and hiv/aids mortality rates become more controlled, non-communicable diseases (ncds) are emerging as one of the major healthcare burdens facing the country.[1] in fact, this rise in ncds, coupled with maternal and infant mortality rates, form two of the four main threats to the health of south africans.[2] ncds are said to account for 21% of life years lost in sa.[1] in particular, the obesity epidemic has been increasing, with the most recent statistics reporting that 61% of the sa population are reportedly overweight or obese, with the prevalence being particularly high in women.[2] there is strong evidence for the role of physical activity (pa) in reducing the risk and burden of ncds,[3] which is of particular importance in south african women, who appear to be vulnerable to both weight gain and physical inactivity.[4] for example, data from the south african demographic and health survey (2003) showed that two-thirds of south african women are inactive, with physical inactivity being a major contributing factor to the increase in overweight or obesity.[4] according to the first south african national health and nutrition examination survey (sanhanes-1), it appears that the most significant increase in waist circumference, as well as overweight and obesity, occur between 15 and 35 years of age. as this represents childbearing age, it may be the perfect window of opportunity to intervene, not only to optimise the health of the mother but also of her offspring. by optimising health behaviours and contributing to the achievement of the world health organisation’s (who) millennium goals, this may assist in reducing child mortality and improving maternal health. recent preventative medicine research has focused on early life and in utero environmental factors and their effects on future health with some studies showing that, although the genetics of disease cannot be ignored, early life factors may play an important role in the risk of disease.[5] this alludes to the fact that a woman’s health status, both pre-pregnancy and during pregnancy, can significantly influence pregnancy outcomes and the health prospects of the offspring.[5] therefore the importance of optimising the period of pre-pregnancy and pregnancy, and encouraging healthy behaviours during this time, should be emphasised. despite the wealth of evidence to encourage physical activity in the prevention and management of chronic diseases, minimal research exists for the pregnant population, particularly in developing countries. it has been shown that women of lower educational and socioeconomic status are particularly vulnerable to adverse pregnancy outcomes due to limited knowledge around pregnancy and health, including physical activity recommendations.[6] therefore the purpose of this review is to describe the effects of overweight and obesity, and the role of physical activity, on maternal and foetal health outcomes during pregnancy. in addition, the factors that have been shown to influence physical activity participation during pregnancy have been reviewed. the burden of obesity in south africa for almost 20 years south africa has been burdened with an increasing prevalence of ncds, such as cardiovascular disease and type 2 diabetes, overweight and obesity, and their associated disease burdens.[1] although physical inactivity and sub-optimal nutrition are not unique to south africa, the country has gone through drastic economic change and urbanisation, which may have magnified these global trends.[2] unwin et al. suggest that urbanisation, which is associated with an increase in unhealthy dietary behaviours and increased physical inactivity, has the potential to increase the burden of ncds on the healthcare sector.[7] a review by mayosi et al. revealed that the burden of ncds appears to be disproportionately higher in poor people living in urban settings.[1] increased urbanisation has been associated with a rise in the prevalence of hypertension,[7] and bourne et  al.[8] named urbanisation as one of the four independent risk factors for type 2 diabetes. kruger et al.[9] identified urbanisation as one of the top three predictors of increased body mass index (bmi), skinfold thickness, waist circumference and waist-to-hip ratio, all of which were associated with an increase in the prevalence of elevated blood pressure and triglycerides, as well as reduced glucose tolerance and insulin sensitivity. the role of physical activity during pregnancy in determining maternal and foetal outcomes mailto:lisa.micklesfield@uct.ac.za http://dx.doi.org/10.17159/2078-516x/2015/v27i4a440 http://dx.doi.org/10.17159/2078-516x/2015/v27i4a440 94 sajsm vol. 27 no. 4 2015 south african national data have reported that women have a higher bmi and prevalence of obesity than men, with a reported prevalence of overweight and obesity in females between 40-56%.[1,2,4] this is noteworthy, since extensive literature has reported that being overweight or obese prior to, and during, pregnancy has adverse effects on both the mother and the foetus during pregnancy and postpartum.[9,10] obesity and maternal outcomes pre-gravid overweight or obesity has been shown to result in adverse pregnancy outcomes, such as hypertension, pre-eclampsia, gestational diabetes mellitus (gdm), perinatal mortality, macrosomia and complicated deliveries.[10] in addition, women who are overweight or obese prior to pregnancy have a greater risk of miscarriage compared to women with a normal bmi,[10] and may also be at an increased risk of caesarean section delivery.[11] consequently, women who enter pregnancy overweight or obese tend to stay in hospital longer and incur greater financial costs around the time of delivery and postpartum.[10] thus it is advisable that women are at an optimal and healthy body weight prior to falling pregnant in order to improve their chances of a successful pregnancy. excessive gestational weight gain is associated with the development of maternal hypertension and pre-eclampsia.[11] globally, approximately 10% of all pregnancies are complicated by hypertension, which is a major cause of both foetal and maternal morbidity and mortality.[12] in south africa, the latest saving mothers report cited 622 maternal deaths related to hypertensive disorders, with 55.3% from eclampsia, 28.3% from pre-eclampsia and 6.1% associated with chronic hypertension.[13] according to this report, deaths from hypertensive disorders of pregnancy remain the most common direct cause of maternal death.[13] as stated above, since hypertension is closely associated with overweight and obesity, as well as excessive gestational weight gain, there appears to be a need for continual education of women to reduce the risk of developing hypertension, by reducing pre-pregnancy weight and limiting weight gain during pregnancy.[13] similarly, women who enter pregnancy overweight or obese, or gain excessive weight during pregnancy, have an increased risk of developing gdm.[10] although little is known about gdm in africa, a recent systematic review reported a prevalence ranging from 0-13.9%, and an estimated 8.8% in south africa.[14] gdm not only increases the risk of maternal complications, but many studies have shown that children of women with gdm have a higher risk of childhood obesity and metabolic dysregulation later on in life.[15] certainly, in the mother, there appears to be a 40% greater risk of developing type 2 diabetes mellitus (t2dm) within 15 years of giving birth.[13] maternal obesity and foetal outcomes the who recently described the 1 000 days between conception and the child’s second birthday as a critical period for determining the future risk of disease. drake and walker[16] suggest that intergenerational effects may occur as a result of genetic attributes manifesting in a similar manner in both the mother and her child, adverse extrinsic environmental conditions persisting from one generation to the next, or adverse intrauterine conditions resulting in an altered maternal metabolism, which in turn provides an adverse environment for the foetus. for example, high pre-gravid bmi and low pre-gravid insulin sensitivity are strong predictors of increased foetal growth, possibly due to the maternal insulin resistance resulting in greater availability of nutrients to the foetus.[9] pre-pregnancy bmi and gestational weight gain have been found to predict birth weight,[10] with higher bmi being associated with greater risk of delivering large for gestational age infants.[11] several studies have shown that increased birth weight increases the risk of infant mortality and birth trauma, and is also associated with an increased risk of future overweight and obesity in the child.[15] this, in turn, puts the child at risk of developing further complications associated with obesity, such as type 2 diabetes[11] and cardiovascular disease[5] later in life. the role of physical activity in pregnancy in a review by min-lee et al.[3] physical inactivity was equated with smoking and obesity as an established ncd risk factor. indeed, the review estimated that inactivity causes 9% of premature mortality and up to 10% of ncds, worldwide.[3] likewise, in south africa, physical inactivity has been shown to be associated with obesity.[4] therefore pa has an important role to play in the prevention and management of disease, and is also of particular importance during pregnancy. a review by gavard and artal[17] concluded that pa during pregnancy reduces maternal and foetal morbidities, and produces long-term benefits for both the mother and the child. various studies have shown that pa reduces excessive gestational weight gain (gwg) as well as postpartum obesity, and reduces the likelihood of preeclampsia and gestational diabetes.[18] olson and strawderman[19] conducted a prospective cohort study in new york in which socio-demographic characteristics, exercise, food-related behaviours and breastfeeding were assessed using medical records and the responses from a mailed questionnaire. body weight was measured at prenatal visits and one year postpartum. weight retained and major weight gain (4.55 kg) at one year postpartum were the main outcomes.[19] this study showed that physical inactivity during pregnancy is associated with excessive gwg when compared with maintaining or increasing pa levels during pregnancy. similarly, jiang et al.[20] showed that pa levels during pregnancy, as well as pre-pregnancy bmi are inversely associated with gestational weight gain. using pedometry to measure pa, they showed that the sedentary group (<5 000 steps per day) gained 1.45 kg (8% of the total gwg for the sedentary group) more weight during the last two trimesters of pregnancy than the active group (>10 000 steps per day).[20] in addition, a recent review has highlighted the beneficial effect of pa in reducing the risk of pre-eclampsia,[21] possibly via its role in weight management. furthermore, dempsey et al.[22] have shown that pa during pregnancy is associated with a 60% lower incidence of gdm in women who were active before and during pregnancy. in addition to reducing the risk of developing of gestational diabetes, bung and artal[23] also found that exercise has a critical role to play once gdm has been diagnosed, potentially resulting in avoiding insulin therapy. similarly, a longitudinal study by van poppel et al.[24] involving measurements of time spent in moderate-to-vigorous physical activity measured at 15, 24 and 32 weeks of gestation concluded that at-risk pregnant women should be encouraged to increase their pa levels for improved insulin and triglyceride responses. sajsm vol. 27 no. 4 2015 95 patterns of physical activity during pregnancy despite the benefits of regular physical activity during pregnancy,[18] data from the us national health and nutrition estimation survey (nhanes) has shown that the majority of pregnant women are not sufficiently physically active, tending to do less pa than their nonpregnant counterparts, or they reduce their pa during pregnancy.[25] epidemiological research suggests that 40-56% of pregnant women in the united states participate in recreational activity during pregnancy. data from the women in this study report that the majority of pa in pregnant women comes from domestic responsibilities and childcare.[25] although little is known about pa patterns during pregnancy in lower-and-middle income (lmic) countries, a recent study conducted on south african women presenting at two public health clinics in cape town utilised the global physical activity questionnaire to assess pa and its domains. the study showed that women meeting pa guidelines participated in significantly more activity at work and walking for transport than the inactive group. there was very little activity in the leisure domain in both groups. in the same study, average total sitting time (as shown in the gpaq), and excluding time sleeping, for this group of convenientlysampled, pregnant south african women was significantly higher in the group not meeting pa guidelines, than in the sufficiently active group (13.0 ± 3.1 hrs/day vs. 9.1 ± 3.7 hrs/day, p=0.004). similarly, overall sedentary time was higher in the inactivity group (p=0.003) than in the active group (14.9 ± 4.0 hrs/day vs. 10.3 ± 4.2 hrs/day, respectively). furthermore, research on prenatal pa patterns shows that all levels of pa tend to decrease during pregnancy, and physical activities tend to give way to more sedentary behaviours, including watching television and reading.[25] nhanes data on sedentary behaviour during pregnancy have shown that pregnant women in the us spend up to five hours per day watching television, and that sedentary time during pregnancy has been positively associated with increased maternal body weight.[25] in addition, there may be foetal consequences of maternal inactivity. for example, in the avon longitudinal study of parents and children (alspac), sedentary pregnant women were at a greater risk of giving birth to low birth weight babies, than their more active counterparts.[26] therefore although physical activity may have this protective effect, it appears to decline during pregnancy, especially in the leisure domain. factors influencing physical activity during pregnancy several maternal and socio-economic characteristics which influence pa levels have been identified. for example, younger maternal and gestational age have been shown to influence the amount and type of pa. in addition, a lower maternal bmi and better overall health status, is associated with greater activity levels.[25] socio-economic factors, such as a higher education level, social class and income, have all been associated with increased participation in pa during pregnancy.[6,25] parity has also been shown to be associated with pa levels amongst pregnant women. evenson et al.[6] found that women who have three or more children are less likely to engage in leisure time pa than women with less than three children. conversely, liu et al.[27] found that multiparous women are more likely to engage in strenuous activity for at least three hours per week, when compared to nulliparous women. although the authors do not specify the domain of activity, it is possible that this pa is related to child-care activities and domestic work. since international studies have a very different social and environmental context to south africa, factors which influence physical activity participation are also likely to be different in south african women. a recent unpublished study (pearson, micklesfield and lambert, 2013 – honours dissertation) has shown that south african women are more likely to exercise if they have someone to exercise with and somewhere they could go to in order to exercise. the most commonly reported barriers to physical activity during pregnancy appeared to be painful knees, back or abdomen, tiredness and no time to exercise. although the current evidence helps to give a broad idea of factors which may influence pa participation during pregnancy, it is necessary for more research to be done in the south african context in order to support the evidence found in the study described above, since this is the only known source of such information for south african women. this information pertaining to correlates of pa among south african women will allow the development of effective interventions relating to pa during pregnancy. in addition to understanding correlates and patterns of physical activity and sedentary behaviour, it is also essential to understand attitudes and perceptions towards pa in pregnancy. despite the evidence that supports the benefits of pa during pregnancy, many pregnant women frequently report that they are unsure of the safety of exercising during pregnancy and thus reduce their pa after becoming pregnant.[28] in a recent study done in south africa, muzigaba et al.[28] found that although south african women are interested in participating in pa during pregnancy, many were unaware of what is safely recommended. in addition, the women reported a lack of information and advice from healthcare providers, which may explain their safety concerns for themselves and their unborn baby. women also frequently report discomfort, lack of free time, tiredness, pain and lack of social support as reasons for not engaging in pa during pregnancy.[28] conclusion in conclusion, the burden of ncds and obesity in south african women is increasing and placing immense pressure on the healthcare system. due to the role of the intrauterine environment on offspring health, pregnancy has been identified as one of the important periods in life to influence the health of both the mother and child. pa has been shown to be an important factor which may help to improve pregnancy outcomes. however, most of the literature examining pa trends during pregnancy comes from international studies, with limited data on south african women. as such, it is imperative that the pa levels, as well as the beliefs, barriers and facilitators of pa during pregnancy are better understood in a south african context. this would assist in informing public health intervention strategies to reduce the prevalence of ncds and obesity for women and their offspring. conflict of interest. none declared. references 1. mayosi bm, flisher aj, lalloo ug, et al. the burden of non-communicable diseases in south africa. lancet 2009;374(9693):934-947. [http://dx.doi.org/10.1016/s01406736(09)61087-4] 2. baleta a, mitchell f. country in focus: diabetes and obesity in south africa. lancet diabetes endocrinol 2014;2(9):687-688. [http://dx.doi.org/10.1016/s22138587(14)70091-9] http://http://dx.doi.org/10.1016/s0140-6736(09)61087-4 http://dx.doi.org/10.1016/s2213-8587(14)70091-9 http://dx.doi.org/10.1016/s2213-8587(14)70091-9 96 sajsm vol. 27 no. 4 2015 3. lee i-m, shiroma ej, lobelo f, et al. effect of physical inactivity on major noncommunicable diseases worldwide: an analysis of burden of disease and life expectancy. lancet 2012;380(9838):219-229. [http://dx.doi.org/10.1016/s01406736(12)61031-9] 4. dickie k, micklesfield lk, chantler s, et al. meeting physical activity guidelines is associated with reduced risk for cardiovascular disease in black south african women; a 5.5-year follow-up study. bmc public health 2014 may 23;14:498. [http:// dx.doi.org/10.1186/1471-2458-14-498] 5. oken e, gillman mw. fetal origins of obesity. obes res 2003;11(4):496-506. [http:// dx.doi.org/10.1038/oby.2003.69] 6. evenson kr, savitz d, huston sl. leisure-time physical activity among pregnant women in the us. paediatr perinat epidemiol 2004;18(6):400-407. [http://dx.doi. org/10.1111/j.1365-3016.2004.00595.x] 7. unwin n, mugusi f, aspray t, et al. tackling the emerging pandemic of noncommunicable diseases in sub-saharan africa. public health 1999;113(3):141-146. [http://dx.doi.org/10.1038/sj.ph.1900549] 8. bourne lt, lambert ev, steyn k. where does the black population of south africa stand on the nutrition transition? public health nutr 2002;5(1a):157-162. [http:// dx.doi.org/10.1079/phn2001288] 9. kruger hs, venter cs, vorster hh. obesity in african women in the north west province, south africa is associated with an increased risk of non-communicable diseases: the thusa study. br j nutr 2001;86(06):733. [http://dx.doi.org/10.1079/ bjn2001469] 10. galtier-dereure f, boegner c, bringer j. obesity and pregnancy: complications and cost. am j clin nutr 2000;71(5 suppl):1242s-8s. [http://www.ncbi.nlm.nih.gov/ pubmed/10799397] 11. guelinckx i, devlieger r, beckers k, et al. maternal obesity: pregnancy complications, gestational weight gain and nutrition. obes rev 2008;9(2):140-150. [http://dx.doi. org/10.1111/j.1467-789x.2007.00464.x] 12. lindheimer md. hypertension in pregnancy [clinical conference]. hypertension 1993;22(1):127-137. [http://dx.doi.org/10.1161/01.hyp.22.1.127] 13. moodley j. maternal deaths associated with hypertension in south africa : lessons to learn from the saving mothers report, 2005-2007. cardiovasc j afr 2011;22(1):31-35. [http://dx.doi.org/10.5830/cvja-2010-042] 14. macaulay s, dunger db, norris sa. gestational diabetes mellitus in africa: a systematic review. plos one 2014;9(6):e97871. [http://dx.doi.org/10.1371/journal. pone.0097871] 15. catalano pm, kirwan jp, mouzon sh, et al. gestational diabetes and insulin resistance: role in shortand long-term implications for mother and fetus. j nutr 2003;133:1674-1683. 16. drake a, walker b. the intergenerational effects of fetal programming: nongenomic mechanisms for the inheritance of low birth weight and cardiovascular risk. j endocrinol 2004;180(1):1-16. [http://www.ncbi.nlm.nih.gov/pubmed/14709139] 17. gavard j, artal r. effect of exercise on pregnancy outcome. clin obstet gynecol 2008;51(2):467-480. [http://dx.doi.org/10.1097/grf.0b013e31816feb1d] 18. clapp jf. exercise during pregnancy. a clinical update. clin sports med 2000;19(2): 273-286. [http://www.ncbi.nlm.nih.gov/pubmed/10740759] accessed april 7, 2015. 19. olson cm, strawderman ms, hinton ps, et al. gestational weight gain and postpartum behaviors associated with weight change from early pregnancy to 1 y postpartum. int j obes relat metab disord 2003;27(1):117-127. [http://dx.doi. org/10.1038/sj.ijo.0802156] 20. jiang h, qian x, li m, et al. can physical activity reduce excessive gestational weight gain? findings from a chinese urban pregnant women cohort study. int j behav nutr phys act 2012;9:12. [http://dx.doi.org/10.1186/1479-5868-9-12] 21. aune d, saugstad od, henriksen t, et al. physical activity and the risk of preeclampsia. epidemiology 2014;25(3):331-343. [http://dx.doi.org/10.1097/ ede.0000000000000036] 22. dempsey jc, butler cl, sorensen tk, et al. a case-control study of maternal recreational physical activity and risk of gestational diabetes mellitus. diabetes res clin pract 2004;66(2):203-215. [http://dx.doi.org/10.1016/j.diabres.2004.03.010] 23. bung p, artal r. gestational diabetes and exercise: a survey. semin perinatol 1996;20(4):328-333. [http://www.ncbi.nlm.nih.gov/pubmed/8888458] accessed september 8, 2013. 24. van poppel mnm, oostdam n, eekhoff mew, et al. longitudinal relationship of physical activity with insulin sensitivity in overweight and obese pregnant women. j clin endocrinol metab 2013;98(7):2929-2935. [http://dx.doi.org/10.1210/jc.20131570] 25. evenson kr, wen f. national trends in self-reported physical activity and sedentary behaviors among pregnant women: nhanes 1999-2006. prev med (baltim) 2010; 50(3):123-128. [http://dx.doi.org/10.1016/j.ypmed.2009.12.015] 26. both mi, overvest m, wildhagen mf, et al. the association of daily physical activity and birth outcome: a population-based cohort study. eur j epidemiol 2010;25(6): 421-429. [http://dx.doi.org/10.1007/s10654-010-9458-0] 27. liu j, blair sn, teng y, et al. physical activity during pregnancy in a prospective cohort of british women: results from the avon longitudinal study of parents and children. eur j epidemiol 2011;26(3):237-247. [http://dx.doi.org/10.1007/s10654010-9538-1] 28. muzigaba m, kolbe-alexander tl, wong f. the perceived role and influencers of physical activity among pregnant women from low socioeconomic status communities in south africa. j phys act heal 2014;11(7):1276-1283. [http://dx.doi. org/10.1123/jpah.2012-0386] * * references had to be reduced because of constraints on space. a comprehensive list can be obtained from the corresponding author. http://dx.doi.org/10.1016/s0140-6736(12)61031-9 http://dx.doi.org/10.1016/s0140-6736(12)61031-9 http://dx.doi.org/10.1186/1471-2458-14-498 http://dx.doi.org/10.1186/1471-2458-14-498 http://dx.doi.org/10.1038/oby.2003.69 http://dx.doi.org/10.1038/oby.2003.69 http://dx.doi.org/10.1111/j.1365-3016.2004.00595.x http://dx.doi.org/10.1111/j.1365-3016.2004.00595.x http://dx.doi.org/10.1038/sj.ph.1900549 http://dx.doi.org/10.1079/phn2001288 http://dx.doi.org/10.1079/phn2001288 http://dx.doi.org/10.1079/bjn2001469 http://dx.doi.org/10.1079/bjn2001469 http://www.ncbi.nlm.nih.gov/pubmed/10799397 http://www.ncbi.nlm.nih.gov/pubmed/10799397 http://dx.doi.org/10.1111/j.1467-789x.2007.00464.x http://dx.doi.org/10.1111/j.1467-789x.2007.00464.x http://dx.doi.org/10.1161/01.hyp.22.1.127 http://dx.doi.org/10.5830/cvja-2010-042 http://dx.doi.org/10.1371/journal.pone.0097871 http://dx.doi.org/10.1371/journal.pone.0097871 http://www.ncbi.nlm.nih.gov/pubmed/14709139 http://dx.doi.org/10.1097/grf.0b013e31816feb1d http://www.ncbi.nlm.nih.gov/pubmed/10740759 http://dx.doi.org/10.1038/sj.ijo.0802156 http://dx.doi.org/10.1038/sj.ijo.0802156 http://dx.doi.org/10.1186/1479-5868-9-12 http://dx.doi.org/10.1097/ede.0000000000000036 http://dx.doi.org/10.1097/ede.0000000000000036 http://dx.doi.org/10.1016/j.diabres.2004.03.010 http://www.ncbi.nlm.nih.gov/pubmed/8888458 http://dx.doi.org/10.1210/jc.2013-1570 http://dx.doi.org/10.1210/jc.2013-1570 http://dx.doi.org/10.1016/j.ypmed.2009.12.015 http://dx.doi.org/10.1007/s10654-010-9458-0 http://dx.doi.org/10.1007/s10654-010-9538-1 http://dx.doi.org/10.1007/s10654-010-9538-1 http://dx.doi.org/10.1123/jpah.2012-0386 http://dx.doi.org/10.1123/jpah.2012-0386 _goback introduction local cryotherapy is commonly used in the management of acute muscle injuries. 14,20,24,25 despite this, the clinical benefits of cryotherapy for acute muscle injuries are still questioned, because of the lack of suitable randomised controlled studies. 3,12 cooling can be achieved using different modalities such as wet ice, crushed-ice packs, dry ice, frozen gel packs, endothermic chemical reaction packs, refrigerant cooling devices, coolant sprays, cold water baths, cooling blankets, cold air and electrical cooling devices. 2,5,22,24,33 many of the physiological effects of local cooling have been well described. cooling reduces metabolic rate, 10,26,31 local adenosine triphosphate utilisation, 34 bloodflow, 4,10,23 the inflammatory response 23 and oedema formation. 6,11 cooling also has an analgesic effect, slows nerve conduction velocity, and decreases muscle spasm and spasticity. 1,15,18,19,28 there is still controversy over what constitutes the optimal modality, duration and frequency of cryotherapy for muscle injury. 3 the temperature of skin, subcutaneous tissue and muscle has been measured at various depths below the skin before and after different forms of cryotherapy, 2,5,7,14 and adipose tissue has been shown to have an insulating effect, impairing cooling of the underlying muscle. 27,29 in resting muscle, there is normally a temperature gradient, with temperature increasing with depth. 7,16,32 this gradient is altered by cryotherapy. to date, studies on the use of cryotherapy have only original research article the effect of icepack cooling on skin and muscle temperature at rest and after exercise maurice mars1 (mb chb, md) brian hadebe2 (mbchb) mark tufts3 (msc) 1 department of telehealth, nelson r mandela school of medicine, university of kwazulu-natal, durban 2 postgraduate student, private practitioner 3 department of physiology, faculty of health science, university of kwazulu-natal, durban abstract objective. to compare cooling of skin, subcutaneous fat and muscle, produced by an icepack, at rest and after short-duration exhaustive exercise. methods. eight male subjects were studied. with the subject supine, hypodermic needle-tip thermistors were inserted into the subcutaneous fat and the mid-portion of the left rectus femoris, to a depth of 1 cm plus the adipose thickness at the site, and a temperature probe was placed on the skin overlying the needle tips. a pack of crushed ice was applied for 15 minutes and temperatures were recorded before, during, and for 45 minutes after icepack application. thereafter, subjects underwent a ramped, treadmill, vo2max test, an icepack was applied after temperature probes were inserted into the right leg and measurements were made as before. results. after the treadmill run, skin (sk), subcutaneous (sc) and muscle (ms) temperatures (mean ± standard deviation (sd)) were 0.9 ± 1.3, 1.0 ± 0.7 and 1.3 ± 0.8°c higher than at rest. after 15 minutes of icepack cooling, temperatures fell in the exercised limb by 22.7 ± 1.5°c (sk), 13.5 ± 4.2°c (sc) and 9.3 ± 5.5°c (ms) and in the control limb by 20.7 ± 2.9°c (sk), 11.4 ± 2.0°c (sc) and 8.7 ± 2.6°c (ms). the reductions in temperature were significant in both the control and exercised limbs. forty-five correspondence: maurice mars dept of telehealth nelson r mandela school of medicine university of kwazulu-natal pvt bag 7 congella 4013 tel: 031-260-4543 fax: 031-260-4737 e-mail mars@ukzn.ac.za minutes after icepack cooling, muscle temperature was still approximately 5°c lower in both the rested and exercised muscle (p < 0.001). individual variations in response to cooling were noted. conclusions. cooling of superficial muscle occurs after high-intensity exercise. the degree of cooling is not uniform. this may be due to differences in the sympathetic response to cooling, influencing haemodynamic and thermoregulatory changes after exercise. this needs further investigation. 60 sajsm vol 18 no. 3 2006 pg60-66.indd 60 9/21/06 12:16:25 pm pg60-66.indd 61 9/21/06 12:16:25 pm 62 sajsm vol 18 no. 3 2006 investigated subjects at rest. in the athletic setting, it is common to apply an icepack to an injury as soon as the athlete stops competing or training. depending on the intensity and duration of exercise, the athlete’s muscle temperature, core temperature and cardiac output, will have increased. 8,16 these haemodynamic and temperature changes may affect temperature flux under a cooling pack. the aim of this study was to investigate the effect of an icepack on muscle cooling following acute exercise and compare it with muscle cooling in the rested state. methods the study was undertaken with the approval of the biomedical ethics committee of the university of kwazulu-natal. eight adult male volunteers who all exercise on a regular basis, participating in at least four soccer practices and/or matches a week, were studied and all signed informed consent. at a preliminary visit they underwent medical screening and were familiarised with the apparatus and the testing procedures. on the day of testing, subjects lay supine for 15 minutes to acclimatise to the ambient temperature of the laboratory. they were dressed in running shorts and an athletic vest. the site for measurement of temperatures was determined as the point halfway between the anterior superior iliac spine and the superior pole of the patella. the skinfold thickness was measured at this point using skin callipers (john bull skinfold callipers, british indicators, england) and the thickness of adipose tissue was taken as half the skinfold thickness. a cutaneous temperature probe (ysi 4494, yellow springs instrument co) was attached to the skin over the middle of the left thigh in the anterior midline. after cleaning the skin with alcohol, and using aseptic techniques, appropriately sterilised 22g hypodermic, needle-tip thermistors, (ysi inc precision 5510 series) were inserted into the subcutaneous fat and to a depth of adipose thickness plus 1 cm into the quadriceps muscle, so as to lie beneath the skin temperature probe. the needles were inserted from the lateral aspect of the thigh such that the barrel of the hypodermic needle was not under the icepack and the needles were taped to the skin to prevent movement. a needle guide was used to assist needle placement at the correct depth in the muscle. the temperature probes and hypodermic thermistors were attached to a ysi 4000a thermometer and each channel was calibrated using the unit’s selfcalibration. the needles were cleaned and sterilised according to the manufacturer’s instruction after each use. a 20 cm x 10 cm x 5 cm pack of crushed ice in a wet towel was then placed longitudinally over the temperature probe and left in situ for 15 minutes. the icepack was not strapped to the subject and no compression other than the weight of the icepack was applied. temperature measurements were recorded every minute, for 5 minutes before application of the icepack, during the ice application and for 45 minutes after removal of the icepack. thereafter the hypodermic needle probes and skin temperature probe were removed. an hour later subjects underwent a ramped vo2max test on a treadmill using a previously described method. 21 oxygen consumption and carbon dioxide production was measured using open circuit spirometry (oxycon champion, version 4.3 – ce 0434, jaeger). the spirometer was calibrated daily. on completion of the treadmill run, subjects immediately lay supine on a plinth and the temperature probes were attached and inserted into the right leg as previously described. after 5 minutes, an icepack was applied for 15 minutes and recordings were made as before. data are expressed as the mean and one standard deviation and the 95% confidence interval is given where appropriate. the rate of change of temperature per minute was determined by calculating the difference between successive measurements, at 5 minute intervals (δy), and dividing this by 5 (δx). statistical analysis of the differences of means was by paired t-test and the differences of means within and between groups by two-way repeated-measures anova with post hoc testing using the bonferroni test. alpha was set at 5%. results the subjects’ mean ages, heights and weights were 21.3 ± 3.0 years, 172.5 ± 6.6 cm and 61.8 ± 10.2 kg. the adipose thickness of the right thigh was 0.43 ± 0.15 cm and the left 0.43 ± 0.17 cm. the ambient temperature during the study was 21.3 ± 1.7 °c. maximum oxygen consumption was 49.1 ± 4.2 ml.kg -1 .min -1 and this was achieved at a respiratory exchange ratio of 1.15 ± 0.1. treadmill running time was 12.2 ± 1.1 min. the changes in skin, subcutaneous tissue and muscle temperatures are shown in table i and fig. 1. exercise elevated skin and subcutaneous muscle temperatures. the table i. skin, subcutaneous tissue and muscle temperatures in rested and exercised limbs, recorded 5 minutes after starting measurement (the time point immediately prior to the application of the icepack), at the end of cooling (20 min) and after 45 minutes of recovery (65 min), expressed as the mean ± standard deviation and the 95% confidence interval time control °c 95% ci exercise °c 95% ci skin 5 min 28.8 ± 1.4 27.6 – 30.0 29.7 ± 1.3 28.6 – 30.8 skin 20 min 8.1 ± 2.7 5.8 – 10.4 7.0 ± 1.2 6.0 – 8.0 skin 65 min 25.6 ± 1.3 24.5 – 26.6 26.4 ± 1.5 25.1 – 27.6 sc 5 min 33.1 ± 1.1 32.2 – 34.0 34.2 ± 1.1 33.3 – 35.0 sc 20 min 21.7 ± 2.2 19.9 – 23.5 20.7 ± 5.0 16.5 – 24.9 sc 65 min 28.1 ± 1.0 27.3 – 29.0 29.5 ± 2.2 27.7 – 31.4 ms 5 min 34.9 ± 1.2 33.9 – 35.9 36.3 ± 1.1 35.3 – 37.2 ms 20 min 26.2 ± 3.5 23.3 – 29.1 27.0 ± 7.4 21.6 – 32.3 ms 65 min 29.4 ± 1.1 28.4 – 31.4 31.0 ± 3.6 28.8 – 33.1 sc = subcutaneous tissue; ms = muscle. pg60-66.indd 62 9/21/06 12:16:26 pm pg60-66.indd 63 9/21/06 12:16:26 pm 64 sajsm vol 18 no. 3 2006 application of the icepack after exercise resulted, on average, in greater cooling of skin, subcutaneous tissue and muscle, with the skin and subcutaneous tissue temperatures falling to below that of the rested limb and then rewarming slightly faster, so as to be higher than the temperatures of the rested limb 45 minutes after removal of the icepack. the average temperature of muscle after exercise did not fall below that achieved in the rested limb during cooling. this response was not constant and there were individual variations, with some subjects showing a marked reduction in muscle temperature after cooling (fig. 2) and others showing only minimal cooling of muscle after exercise (fig. 3). the time to maximum cooling varied between subjects but was similar for each subject. the average time to maximum cooling of subcutaneous tissue after application of the icepack was 15.1 ± 0.8 min, (95% ci: 15.5 16.7) at rest and 16.6 ± 0.7 min (95% ci: 16.1 17.1) after exercise and in muscle 20.1 ± 4.5 min (95% ci: 17.0 23.2), range 15 29 min at rest and 20.4 ± 3.8 min (95% ci: 17.7 23.0), range 16 28 min, after exercise (fig. 1). the differences were not statistically significant. skin, subcutaneous and muscle temperatures were compared at three fixed time points, 5 minutes after fig. 1. mean skin, subcutaneous (sc) and muscle (ms) temperatures (°c) measured every minute, before, during and after application of an icepack in the rested (c) and exercised (e) limb. the arrows represent the period that the icepack was applied. fig. 3. muscle temperature recorded every minute before, during and after application of an icepack in rested (ms(c)) and exercised muscle (ms(e)) in subject 4. the arrows represent the period that the icepack was applied. fig. 2. muscle temperature recorded every minute, before, during and after application of an icepack in rested (ms(c)) and exercised muscle (ms(e)) in subject 1. the arrows represent the period that the icepack was applied. fig. 5. the average rate of change of temperature per minute of skin, subcutaneous tissue (sc) and muscle (ms) at rest (c) and after exercise (e). fig. 4. the absolute change in temperature (°c) from the start of cooling at 5 min and subsequent measurements, of skin (sk) subcutaneous fat (sc) and muscle (ms) at rest (c) and after exercise (e). cooling occurred between 5 min and 20 min. pg60-66.indd 64 9/21/06 12:16:30 pm sajsm vol 18 no. 3 2006 65 commencing measurement (that is, just prior to the application of the icepack), at the end of icepack application and after 45 minutes of recovery (table i). five minutes after the treadmill run, skin, subcutaneous and muscle temperatures were 0.9 + 1.3°c, 1.1 + 0.8°c and 1.3 + 0.8°c higher than at rest. after 15 minutes of icepack cooling, temperatures fell in the exercised limb by 22.7 + 1.5 °c (skin), 13.5 + 4.2°c (subcutaneous) and 9.3 + 5.5°c (muscle) and in the rested limb by 20.7 + 2.9°c, (skin), 11.4 + 2.0°c (subcutaneous) and 8.7 + 2.6°c (muscle). fortyfive minutes after removing the icepack the reduction in temperature in the exercised leg was 3.3 + 1.3°c (skin), 4.6 + 1.4°c (subcutaneous) and 5.3 + 1.6 °c (muscle) and in the control limb, 3.2 + 0.8°c (skin), 5.0 + 0.7°c (subcutaneous) and 5.5 + 0.9°c (muscle). the fall in temperature after 15 minutes of icepack cooling and after 45 minutes of recovery was significant, p < 0.001 for both the rested and exercised limb, as was the residual reduction in temperature after 45 minutes of recovery, p < 0.001. no differences in cooling were noted between the rested and exercised limbs. as exercise raised skin, subcutaneous and muscle temperature, the absolute changes in temperature produced by cooling and rewarming were referenced to the temperatures at the commencement of the icepack treatment (5 min) (fig. 4). the fall in temperature from before application of the icepack to the end of cooling (20 min) was significant for both rested and exercised limbs, p < 0.001, as was the fall in temperature between the commencement of icepack cooling and the end of the recovery period (65 min) p < 0.001. no differences in cooling were noted between the rested and exercised limbs. the rate of change of temperature per minute is shown in fig. 5. no difference in the rate of change of temperature was noted between cooling and rewarming at rest or after exercise. discussion the main finding of this study is that cooling of superficial muscle in response to an icepack is, on average, similar at rest and after exercise but that there are individual variations. this variability suggests that the haemodynamic and thermal alterations associated with intensive exercise may influence thermal flux at the depths measured, in some individuals. during exercise, muscle temperature rises in response to increased metabolic activity, with a resultant increase in core temperature and arterial and venous blood temperature. 9,16 associated with this is an increase in cardiac output, circulating the warmed blood more rapidly around the body. cooling is based on the second law of thermodynamics, with heat being transferred from a warmer body to a cooler body. for a muscle to cool, heat must be lost from muscle to adjacent cooler muscle tissue or subcutaneous fat. subcutaneous fat will in turn lose heat to skin and finally heat will be dissipated by conduction to the icepack, and by radiation and evaporation to the atmosphere. the efficacy of conduction to the coolant is dependent on the surface area being cooled and the physical properties of the coolant. if arterial blood is warmer than cooling muscle, then the muscle will also gain heat from the arterial blood, thereby assisting in lowering core temperature. at rest there is a temperature gradient in large skeletal muscles, with the muscle tissue nearest the main feeder artery being the warmest and the most superficial muscle tissue, the coolest. 16,30 during exercise this gradient is reduced, and after exercise it would be expected that as muscle cooling takes place, the gradient is re-established. while the rate of cooling was similar before and after exercise, there was a trend for absolute cooling of skin, subcutaneous tissue and muscle to be greater after exercise than at rest, with skin and subcutaneous tissue, which was warmer after exercise, being cooler than resting skin and subcutaneous tissue at the end of the cooling period. similarly the fall in muscle temperature was greater after exercise, but did not fall below that of resting muscle. while the average data show a very similar response to cooling at rest and after exercise, the individual responses were not all the same. similar variability has been reported in previous studies on rested muscle. 5,13,32,33 the variability has been attributed to the insulating effect of different thicknesses of adipose tissue, and individual differences in sympathetic response to local cooling. in this study another possibility is that the needles were not all placed at the correct depths, although every precaution was taken to ensure that they were placed correctly. the sympatho-adrenal system is activated by exposure to an external cold stimulus, and skin cooling in rats has been shown to elicit different sympathetic responses, dependent on the rate of cooling. 17 on the one hand, rapid skin cooling evokes a significant increase in plasma catecholamines with a reduction in skin catecholamines. the fall in skin catecholamines is attributed to their local release to cause vasoconstriction. dermal vasoconstriction with an associated increase in plasma catecholamines may result in muscle arteriolar vasoconstriction with a more rapid fall in muscle temperature as seen in fig. 2. on the other hand, slower cooling is not associated with an increase in plasma catecholamine concentration or a fall in skin concentration. with a reduction in local vasoconstriction, skin and muscle cooling would be slower as in fig. 3. the catecholamine response to intense exercise may also play a role and this needs further investigation. it does not however appear to influence the timing of the local cooling response as the time to maximum cooling in rested and exercised muscle, while varying between subjects, was relatively constant for each subject. differences in exercise-induced catecholamine response may however account for the inter-subject variability in muscle cooling. cooling of skin causes a variable response in deeper tissues. the implications of this are that those who have very rapid skin cooling, while benefiting from the concomitant cooling of muscle, are potentially at risk of developing ice burns and those with a muted response are unlikely to derive the benefits expected from muscle cooling. pg60-66.indd 65 9/21/06 12:16:30 pm 66 sajsm vol 18 no. 3 2006 what is required is a simple test that will elucidate who will have a rapid cooling response and who will have a slower and less effective response. this study shows that cooling of superficial muscle occurs after high-intensity exercise to exhaustion. the degree of cooling is not uniform. this may be due to individual differences in the sympathetic response to cooling, which influence haemodynamic and thermoregulatory changes after exercise, although this was not measured in this study. further studies are required to evaluate the sympathetic response to cooling after exercise and the temperature changes in deeper muscle tissue after exercise of different intensity and duration. references 1. albrecht h, schwecht m, pollmann w, parag d, erasmus lp, konig n. local ice application in therapy of kinetic limb ataxia. clinical assessment of positive treatment effects in patients with multiple sclerosis. nervenarzt 1998; 69: 1066-73. 2. belitsky rb, odam sj, hubley-kozey c. evaluation of the effectiveness of wet ice, dry ice, and cryogenic packs in reducing skin temperature. phys ther 1987; 67: 1080-4. 3. bleakley c, mcdonough s, macauley d. the use of ice in the treatment of acute soft-tissue injury: a systematic review of randomized controlled trials. am j sports med 2004; 32: 251-61. 4. blomgren i, bagge u, johansson br. effects of cooling after scald injury 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1995; 23: 74-6. 11. hochberg j. a randomized prospective study to assess the efficacy of two cold-therapy treatments following carpal tunnel release. j hand ther 2001; 14: 208-15. 12. hubbard tj, denegar cr. does cryotherapy improve outcomes with soft tissue injury? j athl train 2004; 39: 278-9. 13. johnson dj, moore s, moore j, oliver ra. effect of cold submersion on intramuscular temperature of the gastrocnemius muscle. phys ther 1979; 59: 1238-42. 14. jutte ls, merrick ma, ingersoll cd, edwards je. the relationship between intramuscular temperature, skin temperature, and adipose thickness during cryotherapy and rewarming. arch phys med rehabil 2001; 82: 845-50. 15. kanui ti. thermal inhibition of nociceptor-driven spinal cord neurones in the cat: a possible neuronal basis for thermal analgesia. brain res 1987; 402: 160-3. 16. kenny gp, reardon fd, zaleski w, reardon ml, haman f, ducharme mb. muscle temperature transients before, during and after exercise measured using an intramuscular multisensor probe. j appl physiol 2003; 94: 23507. 17. kozyreva tv, tkachenko ey, kozaruk vp, latysheva tv, gilinsky ma. effects of slow and rapid cooling on catecholamine concentration in arterial plasma and the skin. am j physiol 1999; 276: r1668-72. 18. lee su, bang ms, han tr. effect of cold air therapy in relieving spasticity: applied to spinalized rabbits. spinal cord 2002; 40: 167-73. 19. lightfoot e, verrier m, ashby p. neurophysiological effects of prolonged cooling of the calf in patients with complete spinal transection. phys ther 1975; 55: 251-8. 20. macauley dc. ice therapy: how good is the evidence? int j sports med 2001; 22: 379-84. 21. mars m. the metabolic demands of portage in kayak marathons. s afr j sports med 1995; 4: 15-7. 22. mcmaster wc, liddle s, waugh tr. laboratory evaluations of various cold therapy modalities. am j sports med 1978; 6: 291-4. 23. menth-chiari wa, curl ww, paterson-smith b, smith tl. microcirculation of striated muscle in closed soft tissue injury: effect on tissue perfusion, inflammatory cellular response and mechanisms of cryotherapy. a study in rat by means of laser doppler flow-measurements and intravital microscopy. unfallchirurg 1999; 102: 691-9. 24. merrick ma, jutte ls, smith me. cold modalities with different thermodynamic properties produce different surface and intramuscular temperatures. j athl train 2003; 38: 28-33. 25. merrick ma, knight kl, ingersoll cd, potteiger ja. the effects of ice and compression wraps on intramuscular temperatures at various depths. j athl train 1993; 28: 236-45. 26. merrick ma, rankin jm, andres fa, hinman cl. a preliminary examination of cryotherapy and secondary injury in skeletal muscle. med sci sports exerc 1999; 31: 1516-21. 27. myrer wj, myrer ka, measom gj, fellingham gw, evers sl. muscle temperature is affected by overlying adipose when cryotherapy is administered. j athl train 2001; 36: 32-6. 28. oosterveld fg, rasker jj. treating arthritis with locally applied heat or cold. semin arthritis rheum 1994; 24: 82-90. 29. otte jw, merrick ma, ingersoll cd, cordova ml. subcutaneous adipose tissue thickness alters cooling time during cryotherapy. arch phys med rehabil 2002; 83: 1501-5. 30. saltin b, gagge ap, stolwijk ja. muscle temperature during submaximal exercise in man. j appl physiol 1968; 25: 679-88. 31. swenson c, sward l, karlsson j. cryotherapy in sports medicine. scand j med sci sports 1996; 6: 193-200. 32. waylonis gw. the physiological effects of ice massage. arch phys med rehabil 1967; 48: 37-42. 33. wolf sl, basmajian jv. intramuscular temperature changes deep to localized cutaneous cold stimulation. phys ther 1973; 53: 1284-88. 34. yanagisawa o, niitsu m, yoshioka h, goto k, kudo h, itai y. the use of magnetic resonance imaging to evaluate the effects of cooling on skeletal muscle after strenuous exercise. eur j appl physiol 2003; 89: 53-62. pg60-66.indd 66 9/21/06 12:16:30 pm original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license does transversus abdominis function correlate with prone plank and bench bridge holding time in club cricket players? kd aginsky, phd; k keen, bhsc honours; n neophytou, msc (med) centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, south africa corresponding author: kd aginsky (kerithaginsky@gmail.com) cricket is a popular sport that requires the player to produce enough power through the kinetic chain to bowl, bat, or field.[1] this energy transfer is aided by strong core muscles that stabilise and support the spine during vigorous movements.[2] the core is made up of abdominal and lumbar muscles that are divided into local and global muscles based on their role in stability and strength.[3] the deeper lying trunk muscles, such as the transversus abdominis (ta) and lumbar multifidus, act as active stabilisers of the lumbar spine, with stabilisation being attained with the bilateral activity of these muscles. [1, 2] the ta muscle provides segmental stability, postural balance, and contracts to stabilise the body through an increase in intra-abdominal pressure and resisting rotational forces of the spine when forces are applied to the trunk. [4] with pain, the ta muscle becomes inhibited, which may in turn result in spinal instability, and decreasing one’s ability to control the movement of the trunk during sporting activities. [5] ta muscle function can be evaluated with the use of ultrasound and is measured as the change in muscle thickness from rest to contraction. the ta is preferentially recruited at 20% to 30% of maximal voluntary contraction (mvc) during abdominal hollowing, [6] which is achieved by drawing the abdomen towards the spine without tilting the pelvis. [7] abdominal hollowing has been found to preferentially recruit the ta when compared to other lateral abdominal muscles. spine stability is the interaction between the global trunk muscles (rectus abdominis, external oblique and erector spinae) and the local trunk muscles (ta and deep multifidus), as well as the global stabilisers (quadratus lumborum and internal abdominal oblique). [8] stability is achieved by the generation of muscle coactivation patterns and can be measured in many ways. typically, local muscle function has been assessed using fine wire emg or ultrasound during simple tasks such as abdominal hollowing. [9] global muscle stability is measured during activities, such as the isometric bridge hold test, bench bridge and prone plank activities. in most cases, the test evaluates the individual’s ability to maintain a neutral spine during a static holding position.[10] while there is relatively good reliability for the measurement of local muscle stability [4, 11], the reliability of the global muscle stability tests are inherently poor. bridging is a practical and valid method that tests a component of lumbar spine stabilisation. [12] the bench bridge test is used to assess global core muscle strength, and although the reliability is poor, it is considered to have clinical significance. [13] furthermore, it has been postulated by clinicians and trainers that the prone plank and bench bridging trains core stability. however, the relationship between ta muscle function and bridging holding time has not previously been investigated. by assessing this relationship, it could be determined that if one has better ta function they may be able to maintain a bridge exercise for a longer period of time. therefore, the aim of this study is to determine whether there is a relationship between the function of the ta muscle and global core function as measured during bridge and plank holding times. methods study design this was a correlation and descriptive study performed on 17 club cricket players between the ages of 18 to 25 years old. the sample used was one of convenience. individuals without a history of lower back pain or presently suffering from lower back pain were included in the study. ethical clearance was background: bridge and plank holding times are used to evaluate core stability. transversus abdominis (ta) muscle function is assessed using ultrasound and also provides input on an individual’s core stability. objectives: a correlation study comparing ta muscle function with bridge and plank holding time in club cricketers. methods: seventeen male, premier league cricketers (age: 22.1 ± 3.3 years) participated in this study. ultrasound was used to measure bilateral ta, internal oblique (oi) and external oblique (oe) muscle thickness at rest and during abdominal hollowing. muscle function was measured by means of a pearson’s correlation as the change in muscle thickness from rest to abdominal hollowing and compared to holding time of the bench bridge and prone plank (seconds). results: ta muscle thickness was preferentially recruited bilaterally (p=0.00001) during abdominal hollowing. no significant correlations were found between ta muscle function and holding time for the bench bridge (dominant (d): r = 0.03 [95% ci:-0.46-0.50]; non-dominant (nd): r = -0.02 [95% ci:-0.50-0.47]) or prone plank (d: r = -0.16 [95% ci:-0.60-0.34]; nd: r = -0.13 [95% ci:-0.57-0.38]). conclusion: prone plank and bench bridge holding times are not correlated with ta muscle function during abdominal hollowing. core stability cannot rely on a single test to evaluate its effectiveness. in particular, the contribution of the local and global muscle system to ‘core stability’ needs to be evaluated independently. therefore these tests are not sensitive enough to evaluate the contribution of the local muscle system to the global muscle system in a healthy, pain free, sporting population. keywords: core stability, abdominal muscle thickness, abdominal hollowing, bridging s afr j sports med 2022;34:1-4. doi: 10.17159/2078-516x/2022/v34i1a12984 mailto:kerithaginsky@gmail.com http://dx.doi.org/10.17159/2078-516x/2022/v34i1a12984 https://orcid.org/0000-0002-0085-2970 https://orcid.org/0000-0002-7244-4722 https://orcid.org/0000-0001-8460-9347 original research sajsm vol. 34 no.1 2022 2 obtained from the human research ethics committee (m130451) at the relevant institution and all cricketers signed informed consent forms prior to testing. body mass, height and fat percentage body mass (kg) and stature (m) were measured using a safeway scale and seca stadiometer respectively. seven skinfolds were measured to determine the sum of skinfolds (mm) and body fat percentage (%) using the durnin and wormesley formula [14] [100(4.570/d-4.142) where d = 1.1620(0.0630x l) and l=log of four skinfold measurements (triceps, biceps, subscapular and suprailiac sites]. a skinfold caliper and measuring tape were used to measure the skinfolds on the right side of the body, with the cricketer standing upright. the seven sites included the triceps, biceps, subscapular, suprailiac, abdomen, mid-thigh and calf. lateral abdominal muscle ultrasound the lateral abdominal muscles: ta, oi and oe muscles were viewed with a digital ultrasonic diagnostic imaging system (mindray dp-6600, shenzhen mindray bio-medical electronics co., ltd., shenzhen, china) to determine the thickness of the muscles at rest and during abdominal hollowing. scanning was performed on both the dominant (d) and non-dominant (nd) sides to assess muscle symmetry. abdominal hollowing was used to assess muscle function of the ta as this task preferentially recruits the ta, with small changes in the oe and oi muscles, respectively. participants lay supine in the crook-lying position with knees bent to 90o. the transducer head was placed transversely midway between the iliac crest and inferior border of the rib cage in the mid-axillary line, with the medial edge 2.5 cm from the midline, as this allows for all three abdominal muscles to be observed simultaneously. [6, 15, 16] once accurate visualisation of all three abdominal muscles at rest was obtained, the image was frozen and the automatic caliper function was used to measure the muscle thickness of the three abdominal muscles (mm). each measurement was taken as the distance between the edge of the upper and lower inner fascia, represented by the hypoechoic areas on ultrasound, and in three places along the muscle with the average measurement (mm) recorded. the cricketers then performed the abdominal hollowing task at 20-30% of their maximal voluntary contraction without assistance from the spine or pelvis. [15] they were instructed to breathe in deeply and on exhalation, pull their belly button up and inwards gently towards their spine. whilst performing this task, the image was again frozen and the measurement of the muscle thickness (mm) taken as before. ta muscle function was assessed by the change in muscle thickness (δmm) and was calculated as follows: muscle thickness during abdominal hollowing and muscle thickness during rest. prone plank and bench bridge the bench bridge and prone plank tests were used to assess the cricketer’s core strength. [13] the bench bridge was performed with the cricketer lying supine on the floor and placing both feet on a bench, with a height of 30 cm. before performing the prone blank and bench bridge tests, the subjects did a five minute standardised warmup of running drills. each subject was also familiarised with the tests by performing two planks and two bridges prior to the actual test being recorded. prior to the beginning of timing, the cricketer lifted his pelvis so that his shoulders, hips, knees and ankles were in a straight line. once in this position the timer was started. if the cricketer was unable to maintain this body alignment due to discomfort, pain or fatigue, they were given two opportunities to correct their alignment; thereafter the test was terminated, and the time recorded (seconds). the prone plank position was performed with the forearms flat on the floor and elbows perpendicular to the floor. the body was held parallel to the floor when the participant raised his body up onto the toes and the shoulders, hips and knees were aligned. the back was flat, abdominal muscles were contracted and the buttocks did not lift or drop. the time (seconds) that the participants were able to hold the correct position was recorded. a player was allowed to make two corrections to their body position, after which the test was terminated, and the time was recorded. statistical analysis descriptive data were reported as means and standard deviations. student’s t-test was used to assess the change in thickness from rest to the contraction of ta, oi and oe muscles to investigate whether the ta was preferentially recruited, and to assess muscle thickness symmetry (p<0.05). a pearson’s correlation was used to assess the relationship between lateral abdominal muscle function and bridge holding time. statistical significance was taken as 95%. results seventeen male club cricketers (batsmen and bowlers) from premier league cricket teams were tested. the mean age was 22.1  3.3 years; mean height was 1.8  0.1 m, and mean weight was 74.8  7.3 kg. the mean bmi was 23.3  1.6 kg/m2, placing this group in the normal category of 18.5 to 24.9 kg/m2. the sum of skinfolds was 73.5 ± 26.2 mm and the mean body fat percentage was 14.7 ± 4.0%. dominance was taken as the preferred bowling or batting side. thirteen players were right dominant and four were left dominant. lateral abdominal muscle thickness dominant and non-dominant muscle thickness at rest and during abdominal hollowing for the ta, oi and oe muscles are shown in figure 1. when assessing the change in muscle thickness from rest to abdominal hollowing, the ta muscle thickness was found to significantly increase on both the dominant and non-dominant sides (p = 0.00001). importantly, there was no significant change in the thickness of the dominant and non-dominant oi and oe muscles, indicating that the ta muscle was preferentially recruited during the abdominal hollowing contraction. bench bridge and plank holding times the mean holding times for the prone plank (n=17) and bench original research 3 sajsm vol. 34 no.1 2022 bridge (n=16) are shown in table 1. one cricketer was unable to successfully complete the bench bridge due to shoulder pain and was thus excluded from this analysis. lateral abdominal muscle thickness vs bridge holding time there were no significant relationships between the dominant and non-dominant ta muscle function and the amount of time the premier league cricketers were able to hold the bench bridge or prone plank (table 2). there was also no relationship between change in oi muscle thickness and prone plank or bench bridge holding times. discussion change in muscle thickness from rest to contraction (abdominal hollowing) has been shown to be a reliable measure of muscle function for the transversus abdominis.[6, 9] research has shown that the abdominal hollowing contraction preferentially recruits the ta muscle. [15] in this study the ta muscle on both the dominant and nondominant sides showed a significant change in muscle thickness from rest to abdominal hollowing. there was no difference in the change in muscle thickness for the oi and oe muscles bilaterally, thus indicating that the ta muscle was indeed preferentially recruited during the abdominal hollowing task. there was no relationship between the prone plank and bench bridge holding time and ta muscle function. it has been postulated by clinicians that prone plank and bench bridging are measures of core stability. [1, 13] the transversus abdominis muscle’s function, as measured by the change in muscle thickness from rest to contraction, is a component of spinal stability when performed at 30% of a maximal voluntary contraction (mvc). [11] the fact that there were no significant correlations between the prone plank and change in ta muscle thickness or during abdominal hollowing, is likely due to the fact that during the prone plank exercise the global abdominal muscles are primarily recruited [17], thus making this exercise more for core strength and global stability. furthermore, the global muscles are recruited at a higher percentage of mvc compared to the local muscle system. the weak correlations with ta function indicates that it is unlikely that the time the bridging position is held for is associated with deep muscle function, and therefore static bridge tests are not indicative of core stability according to these results. furthermore, it is more likely that bridging is associated with the global strength of the core, which is supported by the findings of kong et al. [18] who found through the use of emg that the rectus abdominis, external oblique, internal oblique and erector spinae muscles were loaded throughout the prone plank. stevens et al. [19] also found that during the unilateral bench bridge the contralateral oe muscle activity was significantly higher than that of the local muscles’ activity, indicating that the bench bridge is more likely to train global core strength than inherent core stability. however, the local and global oblique muscles appear to work simultaneously and may have an important role to play in controlling the neutral spine during bench bridging. [19] however, it may be that during the prone bridge an athlete table 1. mean bench bridge and prone plank holding times for club cricketers bench bridge (seconds) (n=16) prone plank (seconds) (n=17) mean ± sd 172.3  109.0 230.4  91.3 95% ci 104.1 – 220.6 183.4 – 277.3 range 35.0 – 483.0 103.0 – 422.0 table 2. correlation between dominant and non-dominant ta muscle function and holding time for the bench bridge and prone plank in premier league club cricketers muscle function (δmm) bench bridge (n=16) prone plank (n=17) rvalue (95% ci) p-value rvalue (95% ci) p-value transverse abdominis d 0.03 (-0.46 – 0.50) 0.92 -0.16 (-0.60 – 0.34) 0.53 transverse abdominis nd -0.02 (-0.50 – 0.47) 0.95 -0.13 (-0.57 – 0.38) 0.63 internal oblique d 0.26 (-0.18 – 0.70) 0.33 0.24 (-0.29 – 0.64) 0.36 internal oblique nd -0.36 (-0.47 – 0.50) 0.89 -0.07 (-0.50 – 0.46) 0.79 d, dominant; nd, non-dominant; δmm, change in muscle thickness. fig. 1. mean absolute resting and contracted bilateral muscle thickness (mm) of the ta, oi and oe muscles in premier league club cricketers (n =17). ta, transversus abdominis; oi, internal oblique; oe, external oblique; d, dominant; nd, non-dominant. * ta d rest vs. ta d abdominal hollowing (p = 0.00001); # ta nd rest vs. ta nd abdominal hollowing (p = 0.00001). original research sajsm vol. 34 no.1 2022 4 needs to perform an abdominal hollowing task in order to increase stability and thus perhaps increase the holding time of the bridge. it is recommended that further research be performed following this method for improved lumbar stabilisation assessment. [20] as previously mentioned, the local muscle system works at a much lower percentage of mvc, and as all the subjects were pain free, the effect of not having an adequately functioning deep muscle system on core stability is difficult to assess. it is recommended that subjects whose deep muscle system has been affected by lower back pain be assessed to determine this effect. the sample size of this study was small due to a sample of convenience being tested. therefore, the ranges, as well as the confidence intervals, show a high amount of variation. furthermore, the bench bridge and prone plank tests have poor reliability which may affect the accuracy of the measurements and may be confounding factors. conclusion there was no correlation between the prone plank and bench bridge holding times and ta muscle function. the prone plank and bench bridge tests are not sensitive enough to evaluate the contribution of the local muscle system to the global muscle system in a healthy, pain free population. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: ka was involved in the conception, design, analysis and interpretation of the data, drafting or critical revision for important intellectual content and approval of the version to be published. nn was involved in the analysis and interpretation of the data, drafting or critical revision for important intellectual content and approval of the version to be published. kk was involved in the conception, design, analysis and interpretation of the data, and drafting or critical revision for important intellectual content. references 1. king m. core stability: creating a foundation for functional rehabilitation. athletther today 2000; 5(2):6-13. [doi: 10.1123/att.5.2.6] 2. panjabi mm. the stabilizing system of the spine. part ii. neutral zone and instability hypothesis. j spinal disord 1992; 5(4):390-396. [doi: 10.1097/00002517-199212000-00002][pmid: 1490035] 3. bergmark a. stability of the lumbar spine. a study in mechanical engineering. acta orthop scand suppl 1989; 230:1-54. [doi: 10.3109/17453678909154177][pmid: 2658468] 4. hodges pw, richardson ca. altered trunk muscle recruitment in people with low back pain with upper limb movement at different speeds. arch phys med rehabil 1999; 80(9):1005-1012. [doi: 10.1016/s0003-9993(99)90052-7][pmid: 10489000] 5. kibler wb, press j, sciascia a. the role of core stability in athletic function. sports med 2006; 36(3):189-198. [doi: 10.2165/00007256-200636030-00001][pmid: 16526831] 6. hodges pw, pengel lh, herbert rd, et al. measurement of muscle contraction with ultrasound imaging. muscle nerve 2003; 27(6):682-692. [doi: 10.1002/mus.10375][pmid: 12766979] 7. hides j, stanton w, freke m, et al. mri study of the size, symmetry and function of the trunk muscles among elite cricketers with and without low back pain. br j sports med 2008; 42(10):809-813. [doi: 10.1136/bjsm.2007.044024][pmid: 18065440] 8. o'sullivan pb, phyty gd, twomey lt, et al. evaluation of specific stabilizing exercise in the treatment of chronic low back pain with radiologic diagnosis of spondylolysis or spondylolisthesis. spine (phila pa 1976) 1997; 22(24):2959-2967. [doi: 10.1097/00007632-199712150-00020][pmid: 9431633] 9. mcmeeken jm, beith id, newham dj, et al. the relationship between emg and change in thickness of transversus abdominis. clin biomech 2004; 19(4):337-342. [doi: 10.1016/j.clinbiomech.2004.01.007] 10. brown sh, vera-garcia fj, mcgill sm. effects of abdominal muscle coactivation on the externally preloaded trunk: variations in motor control and its effect on spine stability. spine (phila pa 1976) 2006; 31(13):e387-393. [doi: 10.1097/01.brs.0000220221.57213.25][pmid: 16741438] 11. teyhen ds, miltenberger ce, deiters hm, et al. the use of ultrasound imaging of the abdominal drawing-in maneuver in subjects with low back pain. j orthop sports phys ther 2005; 35(6):346-355. [doi:10.2519/jospt.2005.35.6.346] [pmid: 16001906] 12. escamilla rf, lewis c, pecson a, et al. muscle activation among supine, prone, and side position exercises with and without a swiss ball. sports health 2016; 8(4):372-379. [doi: 10.1177/1941738116653931][pmid: 27302152] 13. dennis rj, finch cf, mcintosh as, et al. use of field-based tests to identify risk factors for injury to fast bowlers in cricket. br j sports med 2008; 42(6):477-482. [doi: 10.1136/bjsm.2008.046698] [pmid: 18390922] 14. durnin jv, womersley j. body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. br j nutr 1974; 32(1):77-97. [doi: 10.1079/bjn19740060] [pmid: 4843734] 15. critchley d. instructing pelvic floor contraction facilitates transversus abdominis thickness increase during lowabdominal hollowing. physiother res int 2002; 7(2):65-75. [doi: 10.1002/pri.243][pmid: 12109236] 16. mangum lc, sutherlin ma, saliba sa, et al. reliability of ultrasound imaging measures of transverse abdominis and lumbar multifidus in various positions. pm r 2016; 8(4):340347. [doi: 10.1016/j.pmrj.2015.09.015][pmid: 26428485] 17. ekstrom ra, donatelli ra, carp kc. electromyographic analysis of core trunk, hip, and thigh muscles during 9 rehabilitation exercises. j orthop sports phys ther 2007; 37(12):754-762. [doi: 10.2519/jospt.2007.2471][pmid: 18560185] 18. kong ys, cho yh, park jw. changes in the activities of the trunk muscles in different kinds of bridging exercises. j phys ther sci2013; 25(12):1609-1612. [doi: 10.1589/jpts.25.1609] [pmid: 24409031] 19. stevens vk, bouche kg, mahieu nn, et al. trunk muscle activity in healthy subjects during bridging stabilization exercises. bmc musculoskelet disord 2006; 7:75. [doi: 10.1186/1471-2474-7-75] 20. garcia-jaen m, cortell-tormo jm, hernandez-sanchez s, et al. influence of abdominal hollowing maneuver on the core musculature activation during the prone plank exercise. int j environ res public health 2020; 17(20): 7410. [doi: 10.3390/ijerph17207410] [pmid: 33053717] original research 72 sajsm vol. 27 no. 3 2015 background. the tackle is an important component of rugby union. the tackle situation carries the highest risk for injury for both the ball carrier and tackler. little is known about the epidemiology of tackle injuries in koshuis rugby players. objectives. to (i) calculate the tackle-related injury rate, (ii) determine if the tackler or ball carrier is more susceptible to injury, and (iii) determine the most common location and type of injury during tackles. methods. data were collected by means of injury report forms from the medical centre during koshuis matches of 2012 and 2013. all data collected were captured into an online database. only data related to tackle injuries were evaluated for this retrospective, descriptive epidemiological study. results. the tackle led to 61% of all injuries (11.4 injuries/1 000 playing hours). the tackler sustained 23% more injuries than the ball carrier. injuries to the face (3.1 injuries/1 000 playing hours, 95% confidence interval (ci) 2.8 3.3) were most prevalent. the most common type of injury was lacerations (3.4 injuries/1 000 playing hours, 95% ci 3.2 3.7). conclusion. the tackle contributed to 61% of all injuries, making it the most dangerous phase of play. the tackler is more at risk than the ball carrier, especially for injuries to the face, with lacerations having the highest prevalence. for the ball carrier the location of the most injuries was the head, although joint sprains were the most common type of injury for the ball carrier. s afr j sports med 2015;27(3):72-75. doi:10.7196/sajsm.8091 tackle-injury epidemiology in koshuis rugby players at stellenbosch university e mathewson, bsc (hons) (biokinetics); r grobbelaar, bsc (hons) (biokinetics) department of sport science, stellenbosch university, stellenbosch, south africa corresponding author: e mathewson (lizmat008@gmail.com) since rugby union became a professional sport in 1995, the number of tackles has increased substantially.[1] the increase in the number of tackles in match play may be due to law changes or strategies used by coaches and teams. in rugby union, a tackle occurs ‘when a ball carrier (attacking player) is held by one or more opponents and is brought to ground’. the opposition player (defending player) is referred to as the tackler.[2] the major aim of tackling is to prevent the attacking team from gaining territory and scoring points. the contact nature of the tackle event attributes to muscle damage, which is measured by increased circulating creatine kinase (ck) activity. elevated ck levels can also result from high-speed running, especially in backline players where high force, eccentric work is performed several times during a match. literature has shown a positive relationship with increased frequency of tackles and muscle damage in both players (i.e. tackler and ball carrier). a reduction in neuromuscular function may be associated with muscle damage and thereby predispose players to injury.[3,4] the physical nature of the tackle exposes both players to injury.[3] according to brooks and kemp[5] rugby has the highest risk of injury during a match compared with any other team sport. the basic skill of tackling is the most frequent phase of play as it is used by both teams while they are defending. the study by quarrie and hopkins[1] revealed that tackles accounted for up to 58% of all injuries during match play in professional new zealand teams from 2003 to 2005, making it the most high-risk phase of play. the law of energy conservation is of prevalence during tackle situations as the total momentum of the two players before the tackle is redistributed between them at impact. speed differentiation between the players contributes to the risk associated with the tackle event, as the player with the lower momentum was more frequently injured.[1] furthermore, the distribution of the momentum emphasises the players’ physical conditioning, body position and velocity during the tackle.[3] by comparing current literature, it is clear that a higher overall incidence of injuries correlates with a higher level of play, given that players become bigger and stronger due to more sophisticated conditioning programmes, more training time, and participating in longer seasons.[6-8] thus players are able to generate higher forces during collision events, which exposes them to a higher potential risk of injuries. young players (17 21 years) are especially at higher risk when they compete at a more competitive level as they are still going through musculoskeletal developmental changes, which may be seen in some koshuis (university residence) rugby players.[8] a koshuis rugby team typically consists of university players at different skill and conditioning levels. there are no studies in south africa, to the researchers’ knowledge, assessing rugby tackle injuries in koshuis rugby players. it may be that these players are at greater risk for injury, as they do not train frequently even though the level of competition is high. few studies have specifically investigated tacklerelated injuries, and discrepancies are found in the literature regarding the most frequent body part injured, type of injury, as well as the risk for the ball carrier or tackler to sustain an injury. therefore, well-designed epidemiological studies are needed to investigate the risk of injury. these data can assist coaches and trainers in increasing the safety of the players by improving their tackling technique, thereby minimising the risk for injury. if coaches are aware of the areas of play with increased risk of injury, they can design training drills to minimise the risk thereof. sajsm vol. 27 no. 3 2015 73 the primary objective of this study was to analyse tackle injury epidemiology and the risk thereof in koshuis rugby players at stellenbosch university over the 2012 and 2013 seasons. more specifically, the objectives were to determine (i) the amount of tacklerelated injuries per 1 000 playing hours in university koshuis rugby matches, (ii) if the tackler or ball carrier is more susceptible to injury, and (iii) the most common injury type and injury location during tackles in university koshuis rugby matches. methods this study fol lowe d a ret rosp e c t ive, descriptive design that spanned over two koshuis rugby seasons (2012 2013). population the study included male rugby players between the ages of 18 and 25 years that participated in stellenbosch university’s koshuis rugby league during the 2012 and 2013 seasons. ethical clearance was obtained from the stellenbosch university research et h i c s c om m itte e : hu man r e s e arch (humanities) as well as the institutional research and planning committee (proposal number: hs1034/2014). instruments and data collection procedure data were collected in the medical centre using an adapted version of the international rugby board’s (irb) rugby injury consensus group (ricg) standardised injury report form to ensure validity and repeatability and to present the data in a form that is comparable to other studies. [9] the researchers, who were assisting the onsite medical doctor, collected data verbally from the injured player or a witness after a medical diagnosis was given. once recorded, anonymous data were captured in an online database with limited access. only data related to tackle injuries were evaluated for the purpose of this study. it is assumed that all injuries were reported and the injury report forms were completed accurately. severity and time-loss due to injury was not accurately determined on-site and was therefore not used for the purpose of this study. with the data collection in the medical centre, it was sometimes unclear whether the injured player was the tackler or the ball carrier during the tackle event. injuries to these players were categorised as ‘uncertain player’ injuries. this was accounted for in the overall calculations, but could not be used for specific player comparisons. statistical analyses injury rate and 95% confidence intervals (cis) were calculated by means of microsoft excel 2010 to compare the rate of injuries per 1 000 playing hours.[10] the injury rate was calculated as the number of injuries (to each group, i.e. tackler, ball carrier or overall) divided by the exposure time (in hours) multiplied by 1 000. the difference was considered statistically significant if the 95% cis did not overlap. the 95% cis were calculated by means of the following formula: results tackle-related injury rate from 253 injuries, the overall injury rate calculated to 18.9/1 000 playing hours with the tackle contributing to 11.4 injuries/1 000 playing hours (61%). none of the tacklerelated injuries were due to foul play or a violation of the laws. tackler and ball carrier injury susceptibility over the two seasons, the tackler sustained a significantly higher injury rate than the ball carrier (fig. 1). injury location table 1 summarises the injury location of the players over the two seasons. overall, the head sustained the highest injury rate per 1 000 playing hours, followed by the face, shoulder and knee, respectively. the tackler most commonly sustained injuries to the face, while the head was the most commonly injured site among the ball carriers (table 1). only slight differences occurred in shoulder, knee and ankle injuries between the tackler and ball carrier (table 1). injury type table 2 summarises the injury type of the players over the two seasons. over both seasons, the most common injury types, in order of magnitude were lacerations, joint sprains and concussions. lacerations were the most common type of injury among tacklers. this was followed by joint sprains and concussions. among ball carriers, joint sprains were most prevalent followed by lacerations, concussions, ligament injuries, and fractures with the same injury rate (table 2). skin injuries included skin abrasions and lacerations. only the tackler sustained skin abrasions. the tackler also sustained significantly more lacerations than the ball carrier for both seasons (table 2). joint injuries included joint sprains and ligament injuries (table 2). the rate of joint sprains was significantly higher in the ball carrier than in the tackler. the ligament injuries of tacklers and ball carriers were not significantly different. the tackler sustained significantly more concussions than the ball carrier (table 2). discussion tackle-related injury rate the overall injury rate of 18.9 injuries/1 000 playing hours was observed. this is a higher rate than observed in high school rugby 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 !" in ju ry r at e (/ 1 00 0 p la yi n g h o u rs ) tackler ball carrier * fig. 1. injury susceptibility (rate/1 000 playing hours) to tackler (n=73) and ball carrier (n=54) during the tackle situation (*statistically significant difference p<0.05). 95% ci = injury rate 1 000 × 1 000 no. injuries exposure time 1.96± 74 sajsm vol. 27 no. 3 2015 players in 2008 (15.2 injuries/1 000 playing hours).[7] this trend is supported by jakoet and noakes,[6] mcintosh et al.[11] and palmergreen et al.,[8] who found an increase in injury rate with increased age and level of play. a tackle-injury rate of 11.4 injuries/1 000 playing hours was observed for all players injured in the tackle situation. in the present study, the tackle contributed to 61% of all injuries. literature reports the tackle to be the most dangerous phase of play as 40 64% of injuries were sustained as a result of a tackle. [5,7,8,12] this also holds true for koshuis rugby based on the data presented here. tackler and ball carrier injury susceptibility this study found that throughout the two seasons, the tackler sustained a higher injury rate than the ball carrier, as they may have poor tackle technique. quarrie and hopkins[1] also support this finding (table 1). this is contrary to other studies on higher levels of play, that found that the ball carrier is at greater risk than the tackler.[5,8,13] this might be because the players are well-trained, conditioned, and had a better tackle technique. this conclusion was supported by hendricks and lambert[3] who reported that at amateur level (as with some koshuis rugby players), the tackler is more at risk for injury, whereas at the professional level, the ball carrier has the greatest risk. contrary to this, a systematic review of eleven studies found that adolescent ball carriers generally sustained more injuries (17 65%) than tacklers (19 40%).[14] injury location overall, the head sustained the highest injury rate, as also seen in the literature,[7,12,13,15] followed by the face. as there is no clear definition to distinguish between head and face injuries, this could be misinterpreted and should be specified on the injury report form. even though shoulder and knee injuries were common, they showed a lower incidence rate compared with head and face injuries. conversely some research found that the shoulder was one of the most frequently injured locations.[13] the tacklers’ most common injury was to the face, while the ball carriers’ most common injury was the head (table 1). shoulder injuries were the third most common type of injury for all players. this is consistent with the literature that found shoulder injuries to be the third most common for the two players combined.[7,11] mcintosh et al.[11] found that the knee was the second most frequently injured body part for both players. however in this study the knee was the fourth most frequently injured body part (table 1). in this study, ankle injuries were the 5th most frequent injury with the ball carriers having a higher rate of ankle injuries than the tackler. this is contrary to the finding of collins et al.,[7] who found that the ankle was injured second most frequently for the tacklers and ball carriers combined. lower limb injuries to the table 1. injury location and overall and respective injury rates (per 1 000 playing hours) body location tackler ball carrier overall rate 95% ci rate 95% ci rate 95% ci head* 1.3 1.2 1.5 0.9† 0.8 1.0 3.1† 2.8 3.3 face* 1.8† 1.6 2.0 0.4 0.4 0.5 2.8 2.6 3.1 neck 0.0 0.1 0.1 0.2 0.3 0.2 0.4 lower back 0.1 0.0 0.1 0.0 0.1 0.0 0.1 pelvis 0.0 0.1 0.0 0.1 0.1 0.0 0.1 shoulder 0.9 0.8 1.0 0.8 0.7 1.0 1.9 1.7 2.1 clavicle 0.0 0.1 0.1 0.2 0.2 0.2 0.3 upper arm 0.1 0.0 0.1 0.1 0.0 0.1 0.1 0.1 0.2 elbow 0.0 0.1 0.0 0.1 0.1 0.0 0.1 wrist 0.1 0.1 0.2 0.1 0.0 0.1 0.2 0.2 0.3 hand 0.3 0.2 0.4 0.1 0.0 0.1 0.4 0.3 0.5 hip 0.1 0.0 0.1 0.0 0.1 0.0 0.1 groin 0.0 0.1 0.0 0.1 0.1 0.0 0.1 knee 0.4 0.3 0.5 0.6 0.5 0.7 1.0 0.9 1.2 lower leg 0.1 0.0 0.1 0.1 0.0 0.1 0.1 0.1 0.2 ankle 0.3 0.2 0.4 0.4 0.4 0.5 0.8 0.7 1.0 total 5.5 5.1 5.8 4.0 3.7 4.3 11.4 10.9 11.9 * statistically significant difference between tackler and ball carrier (p<0.05). † most prevalent body location. table 2. injury type and overall and respective injury rates (per 1 000 playing hours) injury type tackler   ball carrier   overall rate 95% ci rate 95% ci rate 95% ci concussion* 0.7 0.6 0.9 0.4 0.4 0.5 1.4 1.2 1.6 bone fracture 0.3 0.2 0.4 0.4 0.4 0 .5 0.8 0.7 1.0 dislocation 0.1 0.1 0.2 0.0 0.1 0.1 0.2 subluxation 0.0 0.1 0.0 0.1 0.1 0.0 0.1 joint sprain* 1.0 0.8 1.1 1.3† 1.2 1.5 2.4 2.2 2.6 ligament injury 0.3 0.2 0.4 0.4 0.3 0.5 0.8 0.7 1.0 muscle strain 0.0 0.1 0.0 0.1 0.2 0.2 0.3 contusion/bruise 0.2 0.2 0.3 0.3 0.2 0.4 0.5 0.4 0.6 skin abrasion 0.2 0.2 0.3 0.0 0.4 0.4 0.5 laceration* 1.9† 1.7 2.1 0.7 0.6 0.8 3.4† 3.2 3.7 unsure 0.4 0.4 0.5 0.3 0.2 0.4 1.0 0.8 1.1 other 0.1 0.1 0.2 0.0 0.1 0.1 0.2 total 5.5 5.1 5.8   4.0 3.7 4.3   11.4 10.9 11.9 *statistically significant difference between tackler and ball carrier (p<0.05). † most prevalent injury type. sajsm vol. 27 no. 3 2015 75 ball carrier were usually as a result of loading with the weight of the tackler.[1] injury type for both groups of players combined, the three most prevalent injury types were, in order, lacerations, joint sprains, and concussions. the most common type of injury among the tacklers was lacerations followed by joint sprains and concussions. among the ball carriers, joint sprains were the most prevalent followed by lacerations, and then equally by concussions, fractures and ligament injuries (table 2). other studies have shown lacerations and concussions were mostly caused by player-to-player contact, rather than player-to-surface contact. protective headgear might decrease the amount of lacerations to the head, although for the purpose of this study it was not investigated. skin injuries comprised skin abrasions and lacerations. only the tackler sustained skin abrasions. the tackler also sustained significantly more lacerations than the ball carrier in both seasons. all the lacerations were to the head and face area, correlating with the high inci dence of head and face injuries for both players, especially the tackler. this could be as a result of the tackler being closer to the ground during impact. the tackler can also be dragged along the ground while the ball carrier is still moving forward, resulting in the tackler hitting the ground first – with or without the added weight of the ball carrier. it was also expected that the tacklers would sustain more lacerations as their heads are frequently exposed to contact with the ball carrier’s legs during the tackle, especially when they aim too far below the waist of the ball carrier.[3] for the ball carrier, joint sprains were the most common type of injury. the ball carrier also had a significantly higher rate of joint injuries than the tackler. this can be due to the way in which the ball carrier unexpectedly makes contact with the ground. the way in which the tackler forces the ball carrier to the ground may also restrict proper joint mechanics and predispose the ball carrier to joint sprains. a limitation of this study is that data were dependent on the information collected on an injury report form in the medical room. the researchers are reliant on what the injured player, or a witness accompanying the injured player to the medical room, recall from the mechanism leading to the injury. furthermore, the on-site doctor was not always able to determine the severity of injury and therefore some injuries were excluded from this study. for future studies, the injury report form should be accompanied by video analysis. our current injury report form should be revised, as some categories overlap. the specific categories should be defined (i.e. head and face) and data collectors should be educated accordingly to ensure validity and reliability of data. injury severity and time-loss should be followed up to compare with the literature. conclusion the present study found a total of 253 injuries during 2012 and 2013 in this koshuis rugby population. the tackle accounted for 153 injuries, with a rate of 11.4 injuries/1 000 playing hours. the tackler sustained a higher rate of injury than the ball carrier. the tackler most commonly sustained injuries to the face, with lacerations being the greatest contributor. the ball carrier sustained a lower injury rate and injuries were more equally distributed across the different body parts, with joint sprains being most common. the player most frequently injured and the most common type of injury is in contrast with existing literature. this might be due to a different study population and level of play. koshuis rugby players specifically have a high risk of injury, as they do not train more than twice a week, despite the matches being competitive. the outcome of this study can assist in increasing the safety of the players. for example, a rule could be implemented that players need to attend at least one skill training session per week as faulty technique of the tackler may predispose them to injury. koshuis rugby players compete at an amateur level and their experience, skill, and conditioning levels should be taken into account during team selection. by ensuring all competing players are at a similar level, injury rate could be reduced. also, players should be able to pass a predetermined, rugby-specific test battery before they can be considered for team selection. if coaches are aware of the areas of play with increased risk of injury, they can design training drills to minimise the risk thereof. pitch conditions as well as speed and body weight of players may also contribute to the risk for injury. as pitch conditions are partially controllable, proper pitch maintenance will assist in increased safety for players during a match.[14] the aforementioned strategies might positively influence university rugby players as they will experience less discomfort as well as decreased playing and study time lost due to injury. acknowledgements. the authors would like to thank dr p e olivier, dr k welman, mr w kraak and mr j brown for guidance and reviewing of this project, campus health services for assistance in providing the setting for data collection, all biokinetics students for collecting data, and subcommittee a for funding of the database. references 1. quarrie kl, hopkins wg. tackle injuries in professional rugby union. am j sports med 2008;36(9):1705-1716. [http://dx.doi.org/10.1177/0363546508316768] 2. international rugby board. laws of the game. ireland: international rugby board, 2014. http://www.irblaws. com (accessed 25 june 2014). 3. hendricks s, lambert m. tackling in rugby : coaching strategies for effective technique and injury prevention. int j sports sci coach 2010;5(1):117-135. [http://dx.doi.org/10.1260/1747-9541.5.1.117] 4. jones mr, west dj, harrington bj, et al. match play performance characteristics that predict post-match creatine kinase responses in professional rugby union players. bmc sports sci med rehabil 2014;6(1):38. [http://dx.doi.org/10.1186/2052-1847-6-38] 5. brooks jhm, kemp spt. recent trends in rugby union injuries. clin sports med 2008;27(1):51-73. [http:// dx.doi.org/10.1016/j.csm.2007.09.001] 6. jakoet i, noakes td. a high rate of injury during the 1995 rugby world cup. s afr med j 1998;88(1):45-47. 7. collins cl, lyle mj, yard ee, comstock rd. injuries sustained by high school rugby players in the united states, 2005 2006. arch paediatr adolesc med 2008;126(1):4954. [http://dx.doi.org/10.1001/archpediatrics.2007.1] 8. palmer-green ds, stokes ka, fuller cw, england m, kemp spt, trewartha g. match injuries in english youth academy and school rugby union: an epidemiological study. am j sports med 2013;41(4):749-755. [http:// dx.doi.org/10.1177/0363546512473818] 9. fuller cw, molloy mg, bathgate c, et al. consensus statement on injury definitions and data collection procedures for studies of injury in rugby union. br j sports med 2007;41(5):328-331. [http://dx.doi. org/10.1136/bjsm.2006.033282] 10. knowles sb, marshall sw, guskiewicz km. issues in estimating risks and rates in sports injury research. j athl train 2006;41(2):207-215. 11. mcintosh as, savage tn, mccrory p, frechede o, wolfe r. tackle characteristics and injury in a cross section of rugby union football. med sci sports exerc 2009;42(5):977-984. [http://dx.doi.org/10.1249/mss.0b013e3181c07b5b] 12. bathgate a, best jp, craig g, jamieson m. a prospective study of injuries to elite australian rugby union players. br j sports med 2002;36(4):265-275. [http://dx.doi.org/10.1136/bjsm.36.4.265] 13. bleakley c, tully m, o’conner s. epidemiology of adolescent rugby injuries: a systematic review. j athl train 2011;46(5):555-565. 14. freitag a, kirkwood g, scharer s, ofori-asenso r, pollock am. systematic review of rugby injuries in children and adolescents under 21 years. br j sports med 2015;1-10. [http://dx.doi.org/10.1136/bjsports-2014-093684] 15. holtzhausen lj, schwellnus mp, jakoet i, pretorius al. the incidence and nature of injuries in south african rugby players in the rugby super 12 competition. s afr med j 2006;26(12):1260-1265. 116 sajsm vol 18 no. 4 2006 introduction peripheral vascular disease (pvd) is a leading cause of morbidity in the elderly in the united states where there are an estimated 5 million affected individuals. 9 the prevalence of pvd increases with age and it has been estimated that the biennial incidence rate is 26.6 per 1 000 men and 13.3 per 1 000 women in the united states. 27 in the united kingdom it occurs in approximately 1 in 20 of the population between the ages of 55 and 74 years. 16 data from the framingham heart study revealed that risk factors for pvd include age, gender, serum cholesterol, hypertension, cigarette smoking, diabetes and coronary artery disease. male gender, age and smoking were associated with a 1.5-fold increased risk for pvd; diabetes and stage 2 or greater hypertension conferred a >2-fold increased risk; and coronary heart disease nearly tripled the risk for pvd. 32 these findings are similar to those reported by newman et al. 33 who recognised cigarette smoking as a primary risk factor for pvd. twenty-five per cent of patients with pvd deteriorate steadily but only 5% deteriorate to the point that they require leg amputations. 9,13 intermittent claudication is the most common symptom of pvd; it causes severe walking intolerance and therefore impacts on the functional status and quality of life of the patient. 4,38 therefore treatment has focused on alleviating the symptom of intermittent claudication and improving walking tolerance. measurement of walking tolerance in patients with intermittent claudication to prove that exercise training is effective, walking tests are necessary. set testing protocols on the treadmill are common tools to assess walking tolerance in patients with pvd. a wide variety of treadmill walking tests have been used to quantify improvements in walking distances and functional capacity following training in patients with intermittent claudication (table i). 8,19,28,29,30,41 review article the effects of exercise training in patients with peripheral vascular disease – a review b m parr (msc (med) exercise science)1 e w derman (mb chb, phd)2 1 cape peninsula university of technology 2 university of cape town mrc/uct research unit for exercise science and sports medicine abstract patients with peripheral vascular disease (pvd) suffer from the symptom of intermittent claudication and are therefore intolerant to walking. exercise training has been shown to be a beneficial treatment for patients with pvd. therefore studies have aimed to assess the efficacy of exercise training programmes. this review summarises the data on the efficacy of exercise training programmes in patients with pvd. recommendations are made for the mode, duration, frequency and intensity of exercise training programmes. a systematic review of medline, pubmed and science direct was done of studies on exercise training and patients with pvd, particularly those using randomised controlled trials. exercise training improves walking tolerance in patients with pvd. the common mode of training in patients with pvd in the past decade has been walking on a treadmill; however recently an upper-limb cycle ergometry programme proved to be as effective as lower-limb cycle ergometry in improving walking tolerance in patients with pvd. as weight-bearing walking programmes are uncomfortable for patients with pvd, this is an important development in exercise prescription for these patients. most successful exercise programmes have been 3-6 months in duration for a period of 30 minutes to 1 hour, 2-3 times per week. however, 1 study showed that a shorter period (6 weeks) was of sufficient duration to improve functional capacity in patients with pvd. this is helpful for practitioners as exercise programmes of 3 or 6 months can be daunting correspondence: b m parr department of sport management faculty of business cape peninsula university of technology po box 652 cape town tel: 021-680 1573 fax: 021-680 1562 e-mail: parrb@cput.ac.za for a patient to embark on. finally, patients should exercise to maximal claudication pain in order to elicit the best training response. pg116-121.indd 116 11/23/06 4:08:11 pm sajsm vol 18 no. 4 2006 117 two parameters are usually measured on a treadmill: pain-free walking distance (pfwd) and maximum walking distance (mwd). 8,22,23 use of the treadmill as a tool to measure walking distance has been criticised because the tests are not always reproducible. 26,34,37 there is disagreement about whether a graded test (a test when the speed or gradient increases at set time intervals) is more or less reproducible than a constant load test (one that does not increase in speed or gradient). it has been suggested that a constant load test is fairly reproducible. 3 others have found that both the constant load and the graded exercise test are equally well reproducible. 5 in contrast gardner et al. 17 and perakyla et al. 37 found the progressive test to be more reproducible and gardner et al. 17 suggested that only 1 progressive test is required to obtain table i. review of randomised controlled trials on exercise training and patients with peripheral vascular disease date and exercise mwd pfwd reference treatment no of subjects program length frequency/duration % increase % increase protocol larsen et al. • walking 7 6 months home 1 hr 7x wk 282% 200% 4.6 km.h -1 @ 8% 1966 (28) • control 7 placebo ns ns holm et al. • dle 6 4 months supervised 30 min 3x wk 42% 26%* 1973 (25) • control 6 placebo ns ns mannarino • walk/dle 8 6 months home 1 hr 1x wk 67% 87% 3.2 km.h -1 @ 12% et al. 1989 supervised 1 hr 2x wk grade (30) • placebo 8 placebo ns ns hiatt et al. • treadmill 10 12 wks supervised 1 hr 123% 165% 3.2 km.h -1 at 0% 1990 (22) and ↑3.5% • control 9 no treatment ns ns per 3 min lundgren et al. • operation 13 6 months 600% 300% 4 km.h -1 @ 0% 1989 (29) • op + dle 9 supervised 30 min 900% 400% 3x wk • dle 11 supervised 30 min 200% 300% 3x wk creasy et al. • pta 20 6 months pta ns ns 3 km.h -1 @10% 1990 (8) • dle 16 leg 30 min 2x wk 310% parker-jones et al. • stair-master 6 12 wks supervised 1 hr 2x wk ns ↑35.5s 3.2 km.h -1 at 0% 1996 (35) and ↑ 3.5% per 3 min • treadmill 6 supervised 1 hr ↑171.7 sec ↑117.7 sec 2x wk hiatt et al. • walking 10 12 wks supervised 1 hr 3x wk 43%* 61.6%* 3.2 km.h -1 at 0% 1996 (23) treadmill and ↑ 3.5% per • strength 8 supervised 1 hr 3x wk ns ns 3 min training • control 8 ns ns patterson et al. • supervised 23 12 wks 1x wk lectures + exercise 33.9% 54.5% 1997 (36) exercise • home 23 1x wk lectures + exercise ns ns exercise instruction walker et al. • arm cranking 26 6 wks supervised 40 min 51% 29% shuttle test 2001 (41) 2x per wk • cycling 26 supervised 40 min 57% 31% 2x per wk • control 15 ns ns gardner et al. • walking 28 6 months supervised 77% 134% 3.2 km.h -1 at 0% 2001 (19) 3x per wk and ↑ 2% per • control 24 12% 25% 2 min zwierska et al. • arm cranking 34 24 wks supervised 40 min 47% 122% shuttle test 2005 (44) 2x per wk • cycling 37 supervised 40 min 50% 93% 2x per wk • control 15 ns ns * increase of time in percentage. mwd = maximum walking distance; pfwd = pain-free walking distance; dle = dynamic leg exercises; pta = percutaneous transluminal angioplasty. pg116-121.indd 117 11/23/06 4:08:11 pm 118 sajsm vol 18 no. 4 2006 reliable measurements of pfwd and mwd while 3 tests are necessary when using constant load treadmill tests. it has also been questioned whether walking on the treadmill accurately assesses walking distance because it measures an ‘artificial’ walking distance, i.e. subjects are not walking on land. this was made apparent in a study where 76% of study patients were found to walk much further on a ward corridor walk test than on the treadmill, even though the treadmill was slower. 42 due to this finding, other, less artificial methods of assessing walking capacity have been explored. in a study by montgomery et al. 31 64 patients repeated two 6-minute walk tests a week apart. the distances walked during the two 6-minute walk tests were similar, resulting in a high reliability coefficient (r = 0.94) and a low coefficient of variation (10%). only a small non-significant 3 4% increase in distance and steps was found on the second test. more recently a group of researchers have used a shuttle walk test. 41 patients walk back and forth between 2 cones placed 10 m apart. the speed at which the patients walk is controlled by audible tones recorded on a cassette. patients begin walking on the first tone and aim to reach the second cone by the next tone. the time span between tones is decreased over time thereby increasing the speed. the patient stops walking when he/she cannot keep up with the required speed. the authors found that this test offered the advantage of testing more than 1 patient at a time, and was also reproducible, having less than 10% variability in pfwd and mwd in patients with claudication. future research should use tests that are reproducible. from this review it seems that the 6-minute walk test, the progressive treadmill test and the shuttle test are the preferred tests to use. exercise training as a treatment for patients with pvd percutaneous transluminal angioplasty (pta), as well as vascular bypass grafting are accepted methods of treatment for limb ischaemia. 6,8,43 conservative treatment for claudication was advocated as early as 1898 when wilhelm erb suggested that muscular exercise increased blood flow to the ischaemic limb. 14 despite this recommendation, for many years passive exercise (the limb is moved by the nurse or exercise therapist through its range of motion) was the recognised therapy for these patients. 2 the importance of dynamic (the patient actively performs the exercise him or herself) exercise training as a therapy for patients with intermittent claudication was rediscovered in the 1950s and 1960s. 3,15,28,40 larsen and lassen 28 performed the first randomised controlled study comparing an exercise training group of patients with a placebo-controlled group and found that pain-free walking time (pfwt) increased from 1.7 minutes to 3.5 minutes after exercise training for 6 months. the mean maximum walking time (mwt) increased from 2.9 minutes to 8.2 minutes. in the control group no significant change was noted. since this study a number of randomised controlled trials (table i) have shown similar results. 8,19,22,23,25,29,30,35,36,41,44 it is clear from table i that exercise training improves walking tolerance in patients with pvd. indeed when comparing the effects of exercise training with pta, exercise training was more beneficial after a 6-month period. 8 only 1 study 21 has found no value to exercise training. the effects of surgical intervention, supervised physical exercise training and no treatment on walking tolerance was studied in patients with intermittent claudication. this group found that exercise training offered no therapeutic advantage compared with untreated controls. a methodological flaw in this study was that patients, despite being recruited between 1994 and 1997, were trained using methods dating from the 1970s. the exercises consisted of dynamic leg exercises while seated in a chair. in an upright position exercises consisted of marking time, walking, running, dancing and playing ball. the response to exercise training was determined by using a treadmill walking test and measuring maximum walking distance. furthermore the intervention lasted for 1 year and compliance was not reported for the exercise training group. however earlier findings by this same group reported that surgical reconstruction (vascular bypass graft) combined with exercise training was more effective in improving mwd and pfwd in patients with intermittent claudication than training alone or surgery alone. 29 similarly, in other studies, this group did report improvements in mwd and pfwd in patients with intermittent claudication following exercise training. 10,11 mode of training used in patients with pvd early studies used walking as the mode of exercise training in patients with pvd. 3,28 later studies included ‘dynamic leg exercises’. 10-12 in a study by creasy et al. 8 dynamic leg exercises included ‘walking, walking on tip toe, walking and running on the spot, static bicycling, step ups, going up and down on tip toes while on an incline and dribbling with a ball’. in the early 1990s, treadmills became more commonplace in gymnasia and exercise laboratories and treadmill walking replaced ‘dynamic leg exercises’. studies showed that training on a treadmill produced substantial increases in walking distances. 22,23,35,39 treadmill walking was established as the accepted mode of exercise training and few studies explored the effects of alternative modes of training on walking distances in patients with pvd. two studies did however examine the effects of stairmaster exercise and lower-body resistance training on walking distances in patients with pvd. 24,35 neither mode of training produced improvements in walking tolerance. therefore the researchers concluded that training effects in patients with pvd were specific to the mode of training used. therefore it seemed logical that treadmill walking would be the most beneficial form of training for improving walking tolerance in patients with pvd. pg116-121.indd 118 11/23/06 4:08:11 pm sajsm vol 18 no. 4 2006 119 more recently, studies have again ventured to explore the effects of modes of training outside of treadmill walking on mwd and pfwd in patients with intermittent claudication. polestriding, a stationary form of exercise similar to skiing has proved to be beneficial to patients with intermittent claudication, as has upper-limb cycle ergometry. 7,41,44 the effect of upperlimb and lower-limb cycle ergometry on walking tolerance in patients with intermittent claudication was assessed in the united kingdom. 41,44 patients were randomised to an upperlimb cycle ergometry group or a lower-limb cycle ergometry group and trained twice a week for 6 weeks. 41 pfwd and mwd on a graded treadmill exercise test improved similarly in both training groups. the authors suggested that central cardiovascular adaptations contributed to the increased walking tolerance in both groups because the heart rate response to submaximal work loads during the upper and lower-limb assessments was reduced after training. the authors pointed out that exercise training using lower-limb weight-bearing exercise can be most uncomfortable for the patient and that an upper-limb programme (using upper-limb cycle ergometers) which produced similar results would be a welcome relief to patients with intermittent claudication. however, upper-limb cycle ergometers are not available in most gymnasia. upper-body strength training apparatus is available in all gymnasiums and the efficacy of upper-body strength training programmes on patients with pvd needs to be assessed. it seems that over the years, the mode of exercise training in patients with pvd has mirrored the trends of the mode of exercise training prescribed to the general population. most gymnasium programmes today include a combination of treadmill walking, cycling, strength training (using plateloaded machines) and stretching. it is recommended that future research assess the efficacy of conventional exercise programmes. duration, frequency and intensity of exercise training in patients with pvd the duration of most training programmes, whether home based or hospital based, is 12 weeks 6 months (table i), only 1 study 41 has had a shorter training period (6 weeks). this study showed that training was effective in this time period. 41 more studies need to ascertain whether a short-term (6-week) exercise rehabilitation programme is of sufficient duration to affect functional improvements in patients with pvd. it can be daunting for a patient to embark on a 6-month programme; a short-term (6-week) programme may be easier to commit to and if the patient improves functionally, they will feel encouraged which will improve compliance. although the american college of sports medicine has advocated that 30 minutes of exercise every day is the exercise prescription guideline to obtain the health benefits of exercise, no studies have examined the effects of 30 minutes of exercise every day for patients with pvd. 1 the frequency of most training programmes in patients with pvd has been 2 3 times per week usually for a period of between 30 minutes and 1 hour (table i). this is the most practical for patients with pvd as most people in this group are elderly and do not want to commit to more than 2 3 times a week for exercise training. the effects of intensity of a training programme was examined in a meta-analysis. claudication end point used during an exercise training programme was the most important independently related predictor of the positive change in pfwd and mwd in patients with intermittent claudication. 18 more recently, this same group of researchers assessed the efficacy of a 6-month exercise rehabilitation programme consisting of treadmill walking to near-maximal pain at either 40% or 80% of maximal exercise capacity. those who trained at a lower exercise intensity walked for a longer time period and therefore total work performed in the 2 groups was the same. there was no difference between the 2 groups with respect to mwd and pfwd at the end of the intervention period. both groups improved equally. 20 this indicates that patients should walk at a speed to illicit near-maximal pain. if they choose to train at a lower maximal exercise capacity, they should exercise for a longer period so that the total amount of work completed is similar to that of a training programme using a higher intensity. supervised hospital-based exercise programmes v. home-based exercise programmes in patients with pvd only a few studies have compared the effects of home v. hospital-based exercise programmes in patients with pvd. 36,38,39 regensteiner et al. 38 showed no improvement in mwd or pfwd in a home-based exercise programme after 12 weeks of training. patterson et al. 36 and savage et al. 39 found that although the home exercise groups improved, supervised exercise programmes improved pfwd more than home-based exercise programmes over a 3 6-month period. since only a few studies have compared the effects of home v. hospital-based exercise programmes, more research is needed in this area. conclusion exercise training improves walking capacity in patients with pvd, indeed 1 study proved that exercise training was more beneficial than angioplasty as a treatment for patients with pvd. the preferred mode of exercise training in the past decade has been walking on the treadmill. recent studies have shown that upper-body cycle ergometry proved to be an effective form of treatment for patients with pvd. this is an important development in exercise training for patients with pvd as walking is painful whereas upper-limb cycle ergometry is pain free. furthermore, the efficacy of conventional exercise rehabilitation programmes (a combination of treadmill walking, cycling, strength training and stretching) should be assessed pg116-121.indd 119 11/23/06 4:08:12 pm 120 sajsm vol 18 no. 4 2006 as conventional exercise is the most commonly prescribed exercise in gymnasia today. training programmes of 3 6 months duration have proved to be beneficial for patients with pvd. however a shorter (6-week) exercise training programme has proved to be of sufficient duration to affect functional improvements in patients with pvd. it is easier to encourage a patient to join a 6-week exercise programme than a 6-month programme which can be a daunting undertaking for the patient. it is evident from this review that most studies prescribe half an hour to an hour of exercise 2 3 times per week. the acsm exercise guidelines 1 are half an hour of exercise daily. however, because of the age of these patients it is difficult to expect them to attend daily exercise classes. they can be encouraged to attend classes 2 or 3 times per week and walk at home on the remaining days. both high and low-intensity exercise training programmes have proved to be beneficial for patients with pvd. however, should patients choose to train at a lower maximal exercise capacity, they should exercise for a longer period so that the total amount of work completed is similar to a training programme using a higher intensity. references 1. american college of sports medicine. acsm guidelines for exercise testing and prescription. baltimore: williams and wilkins, 1995. 2. allen ev, barker nw, hines eaj. 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peripheral arterial occlusive disease patients. j am geriatr soc 1988; 46: 706-11. 32. murabito jm, agostino rb, silbershaatz h, wilson pwf. intermittent claudication: a risk profile from the framingham heart study. circulation 1997; 96: 44-9. 33. newman ab, siscovick d, manolio ta, et al. ankle arm index as a marker of atherosclerosis in the cardiovascular health study. circulation 1993; 88: 837-45. 34. ouriel n, mcdonnell ae, metz ce, zarius ck. a critical evaluation of stress testing in the diagnosis of peripheral vascular disease. surgery 1982; 91: 686-93. 35. parker jones p, skinner js, kent smith l, john fm, bryant cx. functional improvements following stairmaster v. treadmill exercise training for patients with intermittent claudication. j cardiopulm rehabil 1996; 16: 47-55. 36. patterson rb, pinto b, marcus b, colucci a, braun t, roberts m. value of a supervised exercise program for the therapy of arterial claudication. j vasc surg 1997; 25: 312-9. 37. perakyla t, tikkanen h, van knorring j, lepantalo m. poor reproducibility of exercise test in assessment of claudication. clin physiol 1998; 18: 18793. 38. regensteiner jg, meyer tj, krupski wc, cranford ls, hiatt wr. hospital v. home-based exercise rehabilitation for patients with peripheral arterial occlusive disease. angiology 1997; 48: 291-300. 39. savage p, ricci ma, lynn m, et al. effects of home versus supervised exercise for patients with intermittent claudication. j cardiopulm rehabil 2001; 21: 152-7. pg116-121.indd 120 11/23/06 4:08:12 pm sajsm vol 18 no. 4 2006 121 40. skinner js, strandness de. exercise and intermittent claudication. circulation 1967; 36: 23-9. 41. walker rd, nawaz s, wilkinson ch, saxton jm, pockley ag, wood rfm. influence of upperand lower-limb exercise training on cardiovascular function and walking distances in patients with intermittent claudication. j vasc surg 2000; 31: 662-9. 42. watson cje, phillips d, hands l, collin j. claudication distance is poorly estimated and inappropriately measured. br j surg 1997; 84: 1107-9. 43. whyman mr, ruckley cv. should claudicants receive angioplasty or just exercise training? cardiovasc surg 1998; 6: 226-31. 44. zwierska i, walker rd, choksky sa, male js, pockley, g saxton jm. uppervs lower-limb aerobic exercise rehabilitation in patients with symptomatic peripheral arterial disease: a randomized controlled trial. j vasc surg 2005; 42: 1122-30. health & medical publishing group surgery of the foot and ankle e-dition, 8th edition text with continually updated online reference by michael j. coughlin, md, private practice of orthopaedic surgery; clinical professor, department of orthopaedics and rehabilitation, oregon health sciences university, portland, or; roger a. mann, md, director of foot fellowship program, oakland ca; associate clinical professor, department of orthopaedic surgery, university of california at san francisco school of medicine, san francisco, ca; and charles l. saltzman, md, professor, departments of orthopaedic surgery and biomedical engineering, university of iowa college of medicine, iowa city, ia isbn 0323040292 · book/electronic media · 1511 pages · 1580 illustrations mosby · forthcoming title (december 2006) health & medical publishing group, private bag x1, pinelands, 7430 tel: 021-6578200 fax: 021-6834509 e-mail: carmena@hmpg.co.za brents@hmpg.co.za health & medical books health & medical books pg116-121.indd 121 11/23/06 4:08:16 pm original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license ‘do we know if we need to reduce head impact exposure?’: a mixedmethods study highlighting the varied understanding of the longterm risk and consequence of head impact exposure across all stakeholders at the highest level of rugby union l t starling,1 msc; c mckay,1 phd; m cross,2 phd; s kemp,3,4 mbbs; k a stokes,1,3 phd ¹ centre for health and injury and illness prevention in sport, department for health, university of bath, bath, uk. 2 premiership rugby limited, twickenham, uk 3 rugby football union, twickenham, uk 4 london school of hygiene and tropical medicine, london, uk corresponding author: l t starling (lindsay@lstarling.com) data for match and training time-loss injuries occurring at the top level of men’s rugby in england have routinely been collected since 2002.[1] these data reveal that concussions account for ~25% of all match injuries.[1,2] most players recover from concussion and return to play without clinical complications in the short-term[3], but it has been suggested that in the medium-to-long term, for some individuals, concussion may contribute to impaired performance, an increased risk of subsequent injury and accelerated neurocognitive decline.[4] whilst attention has mostly been on the recognition and management of concussions over the last decade, in rugby union the emphasis has more recently turned to primary prevention.[5-7] rugby’s welfare focus has also expanded from a consideration of concussive events to encompass all significant head impacts. one element of these efforts is to seek ways to reduce unnecessary head impacts. reducing the incidence of concussions is important; however, it is also important to reduce the frequency of head impacts that do not cause concussions as some evidence suggests that these may also contribute to cognitive decline in the long-term.[8] repeated sub-concussive impacts have been demonstrated to alter white matter structure and cerebral function.[9] while the clinical significance of these alterations is not fully understood, it has been speculated that this could lead to neurodegenerative conditions, such as chronic traumatic encephalopathy.[8] little is known about the frequency and magnitude of head impacts in any rugby activity; however, elite players spend the majority (~93%) of their total active training and match play time in training, with ~20% of this training time spent undertaking ‘contact’ activities.[10] altering the components of match play to reduce head impact exposure is challenging without fundamental law changes but coaching and performance staff have greater control over training activity, and thus training should be considered as a focus for head impact reduction. knowledge and perceptions regarding head impact exposure amongst coaching, medical, conditioning and player stakeholder groups in rugby is largely unknown. with limited objective data on head impacts available to guide training prescription, it is likely that these groups’ views influence practice. therefore, the aims of this study were to describe: (1) how contact training is managed at the elite level of rugby, and (2) how staff and players at this level perceive head impacts and ways to reduce head impact exposure. methods study design this was a pragmatic mixed-methods study conducted from june – august 2021. it followed a sequential explanatory strategy with both primary and explanatory phases of data collection taking the form of concurrent triangulation, whereby quantitative (quan) and qualitative (qual) data were collected at the same time and combined at the point of interpretation (figure 1). both qualitative and quantitative approaches were used in this study to find convergence or corroboration and complementarity, using results from one method to elaborate or clarify results from the other.[11] background: one strategy to prevent and manage concussion is to reduce head impacts, both those resulting in concussion and those that do not. because objective data on the frequency and intensity of head impacts in rugby union (rugby) are sparse, stakeholders resort to individual perceptions to guide contact training. it is unknown whether there is a level of contact training that is protective in preparing elite players for contact during matches. objectives: this study aimed to describe how contact training is managed in elite male rugby, and how staff and players perceive contact training load and head impact load. methods: this was a sequential explanatory mixed-methods study. forty-four directors of rugby, defence coaches, medical and strength/conditioning staff and 23 players across all 13 english premiership rugby union clubs and the national senior team participated in semi-structured focus groups and completed two bespoke questionnaires. results: the study identified the varied understanding of what constitutes head impact exposure across all stakeholder groups, resulting in different interpretations and a range of management strategies. the findings suggest that elite clubs conduct low levels of contact training; however, participants believe that some exposure is required to prepare players and that efforts to reduce head impact exposure must allow for individualised contact training prescription. conclusion: there is a need for objective data, possibly from instrumented mouthguards to identify activities with a high risk for head impact and possible unintended consequences of reduced exposure to these activities. as data on head impact exposure develop, this must be accompanied with knowledge exchange within the rugby community. keywords: contact, concussion, head collision, training s afr j sports med 2022;34:1-9. doi: 10.17159/2078-516x/2022/v34i1a13839 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13839 https://orcid.org/0000-0001-7664-3211 https://orcid.org/0000-0002-5049-2838 https://orcid.org/0000-0002-3250-2713 https://orcid.org/0000-0003-1275-6908 original research sajsm vol. 34 no.1 2022 2 participants data collection occurred in two remotely conducted rounds with staff and players in all 13 english premiership rugby clubs (the highest level of club rugby in england) and the national england senior men’s team. the directors of rugby, defence coaches, heads of medical services and head strength and conditioning coaches from each of the 13 english premiership rugby clubs and the national senior team were purposively targeted for recruitment, as they would be best placed to comment on club and national level approaches to contact training and player management. staff were contacted directly via email by premiership rugby to initiate recruitment. three players from each of the 13 clubs were also targeted for recruitment as they characterised a range of ages, playing positions, and club and national team representation. players were contacted directly by the rugby players’ association to initiate recruitment. individual informed consent was captured via electronic signature from all participants. all staff and players targeted for recruitment agreed to participate in the study. ethical approval was granted by the research ethics approval committee for health at the university of bath (ref:20/21 047). procedures round one online meetings were facilitated with each of the 13 premiership clubs and the national team, with participating staff attending their respective club meetings. five separate player meetings were held, each comprising a range of club representation. online meetings began with a 15-minute presentation where current data pertaining to head impact exposure in matches and training in elite rugby were presented. then, a semi-structured focus group discussion was facilitated by ls. ls has been working in professional rugby research in england for two years and was familiar with some of the participants prior to the focus group discussion but has no rugby playing or coaching experience. a topic guide (supplementary material 1) was used to guide the focus group process; however, participants were encouraged to say as much as they wished. ls encouraged each participant to provide a response to all questions to ensure the views of the different rugby departments were reflected. the focus groups concentrated on how contact training is defined and managed in the participants’ clubs, their opinions on head impact exposure, and possible opportunities to reduce head impact exposure in training. focus groups were audio recorded for transcription which lasted between 30-45 minutes. immediately following each meeting, participants were sent a link to a redcap questionnaire (research electronic data capture, version 8.11.7)[12] (supplementary material 2). the quantitative questionnaire captured further information on clubs’ contact training scheduling and required participants to rate the potential for head impact exposure, as either low, medium, high, seen in 15 exemplar video clips of common training activities (e.g. tackle drills with bags, breakdown drills). the questionnaire was assessed for face and content validity through iterative consultation with academic and individuals with specific rugby relevant expertise. this included selecting the video clips in consultation with these experts to ensure the range of all possible training activities was represented. round two in round two, a link to a redcap questionnaire (supplementary material 3) was sent to all participants, which included a 15-minute recorded presentation of the findings from round one, followed by a series of quantitative and qualitative questions to ascertain if participants agreed with the findings. qualitative questions also probed areas where a lack of convergence emerged in round one. data from round two were analysed and integrated with results from round one to provide credibility to the findings and substantiate areas where there was a lack of agreement between participants.[13] data analysis focus group data were analysed using inductive thematic analysis based on the methods suggested by braun and clarke[14]: transcripts were read several times for familiarisation and inductive semantic coding was used to identify patterns in the data. higher order themes were developed iteratively following a recursive process of reviewing and defining of emerging concepts, with deduced themes discussed amongst the authors to contribute to the trustworthiness of the analysis.[11] qualitative analysis was conducted with the fig. 1. schematic of sequential explanatory, concurrent triangulation, study design. original research 3 sajsm vol. 34 no.1 2022 assistance of nvivo (qsr international; version 12 pro). quantitative analysis of questionnaire data was conducted using stata (statacorp version 16.1, 2019). differences in questionnaire responses between staff and players were assessed descriptively, given the exploratory nature of the research questions. for each video clip, consensus regarding the potential for head impact was established if a category (low, medium, high) was selected by ≥70% of participants.[15] principles from thematic network analysis were used to develop a graphic of emergent themes and the relationships between them to facilitate understanding in the interpretation of the analysis.[16] thematic networks graphically present emergent themes as web-like nets to remove any notion of hierarchy, giving fluidity to the themes and emphasising the interconnectivity between them.[16] the relationships between themes were established based on the authors’ interpretation of the data and connectivity between themes. to corroborate the researchers’ interpretation of the findings and give transparency and credibility to the research, participant quotes from the focus groups are provided throughout the results. results and discussion participant demographics are presented in table 1. the low response rate in round two is a limitation of the study; however, the representation of all demographic groups and unanimity in responses provide credibility to these responses. from the data, three main themes emerged: (1) there is no ‘one size fits all’ approach, with three sub-themes: 1.1: it depends on the time in the season, 1.2: exposure to contact training is necessary to prepare physically and mentally, and 1.3: an individualised approach is desirable. (2) certain scenarios are higher risk for head impact than others, with three subthemes: 2.1: uncontrolled situations are high risk for head impact exposure, 2.2: poor contact technique is a risk factor for head impact exposure and 2.3: greater education and awareness of head impact exposure is needed. (3) the need to objectively identify where head impacts occur, with two sub-themes: 3.1: a holistic approach, considering performance and all injury prevention, is needed and 3.2: there are no reliable and practical methods of collecting objective contact data. a thematic network is presented in figure 2. theme 1: there is no ‘one size fits all’ approach 1.1. it depends on the time in the season staff and players indicated that the weekly volume and composition of contact training varied depending on the time inseason. on average, backs were reported to spend eight minutes per week and forwards 23 minutes per week in fullcontact training activity. participants said contact load progressed over the preseason, with greater volumes of full contact training done in a typical preseason week compared to a typical inseason week. this is in line with previous research in professional rugby showing increased exposure to semi and full-contact training towards the end of preseason, with greater total volumes of training completed in preseason weeks compared to inseason weeks.[10] in-season, the number of days between matches and the stage of the season were taken into consideration. less contact training was typically done in weeks with a short turnaround between matches and in late-season weeks table 1. participant demographics round one round two qualitative focus groups quantitative questionnaire mixed-methods questionnaire staff 44 30 12 directors of rugby (dor) 11 6 3 coaches in addition to dor coaches 7 6 2 head of medical 12 8 6 head of conditioning 14 10 1 players 23 23 7 backs 10 10 3 forwards 13 13 4 total participants 67 53 19 fig. 2. thematic network analysis. main themes presented in black boxes and sub-themes in white. original research sajsm vol. 34 no.1 2022 4 compared to early-season weeks. 1.2. exposure to contact training is necessary to prepare physically and mentally it was unanimous across staff and players that exposure to contact training was necessary to develop and maintain the physical, technical, and mental skills to tolerate the demands of the game, from both performance and injury prevention perspectives. although there is much debate in the load monitoring literature about appropriate metrics and statistical models, available load monitoring research in rugby shows a u-shaped relationship, with players who are exposed to both low and high training loads being more susceptible to injury than those who are exposed to moderate loads.[17] participants' views towards contact load appear to reflect this, with participants suggesting that insufficient contact exposure may increase a player's general injury risk if they have not developed the physical and technical ability to overcome the forces associated with contact events. furthermore, rugby matches were described to be unstructured and unpredictable, and participants highlighted the importance of practising skill execution under these conditions. ‘if you train a skill from a purely technical point of view you then have to take it to an unstructured point as well, whereby they have to anticipate what’s happening around them, otherwise it’s so structured that they don’t know how to make the correct decision under pressure.’ staff 3 forwards indicated that scrumming and mauling are integral parts of match events for their position and felt it important for both technical development and body conditioning aspects that they had some exposure to these events every week. ‘i'd say from a forwards' point of view, as a pack we would definitely want to have a few live scrums and a few live mauls at least each week.’ player 12 1.3. an individualised approach is desirable staff indicated that an individualised approach was taken to prescribing contact training, with the player’s position, match exposure, playing experience and injury status being the primary considerations. staff indicated that older and more experienced players, players with higher match exposure and those experiencing minor injury complaints would typically do less contact training in a week than their counterparts. the concept of ‘top-ups’ was used to describe how individual players may do additional contact training after a session to work on specific areas of weakness. these ‘top-ups’ may be prescribed by coaches or self-opted by players. a few staff indicated that players’ weekly contact training minutes and match contact event numbers were considered when individualising contact training; however, the majority indicated that a subjective approach, based on player observation, informed this individualisation. only one club used objective impact data from instrumented mouthguards to inform their contact training prescription. ‘in terms of data, no – we prescribe on an individual basis, based on injury history, current injury status’ staff 40 players agreed that contact training was modified for age, experience, and injury status; however, unlike staff, who indicated that contact training was individualised from the outset, players felt that contact training was standardised and only ‘top-ups’ were individualised. ‘…if i’m alright to train then you're just doing the same as what everyone else is, which i think is a funny irony when they're managing the metres [of running] so well, there's no real contactloading management.’ player 4 ‘it's pretty standardised week to week, sort of irrespective of game load, or how many minutes you played that weekend or even how many minutes you played that year, etc.’ player 7 theme 2: certain scenarios are higher risk for head impact than others 2.1. uncontrolled situations are high risk for head impact exposure participants indicated that efforts to reduce head impact exposure should be targeted to high-risk areas. they perceived training conducted in live, uncontrolled environments to have a high potential for head impact due to its unpredictable nature and adding a level of control would assist in mitigating the risk. ‘…the prevalence of head knocks would be in an uncontrolled situation, where it’s very much like a match day scenario in training, that it is unpredictable and suddenly you get your head in the wrong place and you’ve got a head impact... and it’s thus trying to coach in a controlled manner.’ staff 9 reducing the number of players, distance and speed of a drill were offered as methods of introducing control to training activities. this reflects research on head injury events in rugby matches, showing the highest propensity for a head injury in high-speed tackles or where more than one tackler is present.[6] incorporating equipment such as tackling shields or carry bags, which are typically padded and used to dampen the impact forces associated with contact, was also suggested. some players, however, felt that the incorporation of padded equipment increased the risk if the player holding the equipment feels more protected and thus confident to hit the tackling player with greater force than an unprotected player would. ‘the pad adds that element of uncertainty, because there’s one guy that’s live [and] there’s one guy that’s not, and you’re running into the pad, and they might hit you a little bit harder than a guy tackling you would.’ player 20 both staff and players described contact training to be fluid and during a training session, the intensity and level of control may change either intentionally or unintentionally. situations were described where a training session may unintentionally increase in intensity because of a few players becoming more competitive, an inevitability due to the nature of the sport. participants indicated that when the intensity of the drill changes and not all players are aware of it, the mismatch in original research 5 sajsm vol. 34 no.1 2022 expected intensity poses a risk to unprepared players. it was felt that it is important in live, uncontrolled training that there is a clear understanding amongst players of the expected level of contact and intensity of the session to ensure they are appropriately primed to avoid high-risk situations under pressure. this contrasts with the discussion in sub-theme 1.2 where participants describe a need for some exposure to unpredictable training to simulate match play. it emphasises the complex nature of balancing contact training with safety. ‘…however you define it, it doesn’t always end up like that. so, in the competitive component … you can be having a game of touch, and then somebody gets pissed off, so he tackles them hard.’ staff 32 ‘when the physicality or intensity level is not clearly defined and people are doing different things, i think you can get yourself in some awkward positions.’ player 5 2.2. poor contact technique is a risk factor for head impact exposure staff and players described poor technique as a risk factor for head impact exposure. players were regarded to be at an increased risk when executing the tackle with incorrect timing, body height or head position. research has also identified tackle technical deficiencies as a risk factor for head impacts and head injury.[18,19] this research shows tacklers to be at an increased risk for head impact when executing the tackle with their head on the incorrect side of the ball-carrier and when not shortening their steps before contact. ballcarriers have been shown to be at an increased risk for head impact when their body is in a ‘straight back’ position precontact and when not being explosive at the point of contact. [18,19] ‘… a lot of guys get head injuries because technically they’ve not executed what they should have done under a severe level of fatigue.’ staff 6 participants indicated a need for greater coach education on the importance of technical development for both injury prevention and performance improvement, suggesting that coaches are more likely to adopt injury prevention strategies if they also have a performance benefit. previous research has identified characteristics of tackles shown to have performance benefits[20], providing support for this suggestion. ball-carrier explosiveness upon contact is associated with better tackle performance and reduced risk of tackle injury.[20] however, tacklers have a higher chance of winning the contest and a reduced risk of injury when tackling with a straight back and the centre of gravity ahead of the support base and shortening steps into contact.[20] some participants felt a need for greater education on how best to conduct technical development training, suggesting that these sessions should be conducted in controlled environments, with the focus on the correct execution of the technical skill as opposed to conducting repeated efforts in match-like environments. many players described training sessions aimed at improving an area of weakness in the team to involve conducting repeated efforts of the specific event in match-like conditions. players felt it would be safer to focus the session on technical execution in a controlled environment. this further highlights the notion in sub-theme 2.1 that conducting training in controlled environments is likely to reduce the risk for head impact exposure. ‘did we miss any tackles at the weekend? yeah, we missed quite a lot – right, let’s do some live tackling... it’s almost a way of trying to solve a problem, rather than understanding why it went wrong’ player 3 2.3. greater education and awareness of head impact exposure is needed all participants described head impact exposure occurring when there was a direct impact to the head, either against another player or the ground. fewer participants described indirect mechanisms, such as an impact on another body part resulting in a whiplash-type motion of the head. emerging research making use of instrumented mouthguards (imgs) to quantify head acceleration events provides evidence for indirect mechanisms, with accelerations to the head being recorded as a result of impact to the body and subsequent momentum transferred to the head.[21] indirect mechanisms have been reported as the most common cause of head impact in male university level rugby players, (31% of all head impact events), with an uncontrolled whiplash action present in many cases, with this present in ~50% of all female rugby impact events.[21] ‘i was going to ask you that question because is it just contact with the head or, that whiplash, that sort of a head rattle that people get... i wouldn't know actually, is that part of it?’ staff 12 it was clear that training drills were designed to mitigate against injury to ensure maximum player availability for match team selection, with head impact exposure no more of a consideration than the protection of any other body region. ‘head injuries have an impact, but also other injuries have an impact. if we’re losing lads in training then they aren’t available then the weekend and then whether it’s a head impact, whether it’s a shoulder, we’re doing something wrong.’ staff 21 overall, there was a lack of agreement on the potential for head impact in the 15 training video clips provided in round one, with 67% (n = 10) of the clips not reaching consensus (figure 3). separating the staff and player responses for the clips where consensus was not reached revealed a mismatch in perceived potential for head impact exposure between staff and players. in each of these clips, players rated the potential for head impact exposure to be higher than staff did (figure 4). the mismatch between interpretations of the potential for head impact exposure was further explored in the data exploration component of round two. both staff and players indicated that this was likely due to the detachment of staff from head impacts in comparison to players experiencing them. ‘players have felt it and many staff only watched it! much of the potential for head impact is unclear hence the need for objectivity and more education to remove the ambiguity.’ staff 3 original research sajsm vol. 34 no.1 2022 6 there is a need for greater education on what constitutes a head impact exposure and the magnitude and frequency of head impact exposures in different match and training activities. enhanced education will equip staff with knowledge on how best to manage exposures in training and will also facilitate alignment between staff and players. theme 3: the need to objectively identify where head impacts occur’ 3.1. a holistic approach, considering performance and all injury prevention, is needed it was unanimous that participants wanted to objectively identify where head impact exposures occur in matches and training. participants had previously highlighted that efforts aimed at reducing head impact exposure should directly target high-risk areas (sub-theme 2.1) and they emphasised the need for these to be objectively identified. fig. 3. proportion of respondents rating the potential for head impact exposure as high, medium, or low for training video clips. data presented as grouped staff and player responses. ** indicates consensus (≥70%) was not reached. fig. 4. proportion of respondents rating the potential for head impact exposure as high, medium, or low for training video clips where consensus (≥70%) was not reached. data presented as staff and player responses separately. original research 7 sajsm vol. 34 no.1 2022 ‘we need to collect more data for a better understanding because then hopefully we can identify drills that will allow us to practice, because we have to practice, but that have minimal exposure to head impacts or high head impacts.’ staff 14 participants highlighted that exposure to rugby-specific contact activity is necessary (sub-theme 1.2) and thus expressed the importance of considering possible unintended performance and injury prevention consequences of reduced contact training exposure. ‘we’d absolutely support any initiative which would maintain the integrity of the game, by reducing head injuries. i don’t necessarily think that it’s going to be a direct correlation between reducing training contact and reducing head injuries, it might have the inverse effect.’ staff 32 ‘we could always limit the potential for head knock exposures at training, but on the flip side, you want to train the skill so that you go confident into the weekend. you don’t want to go for a couple of weeks without training it.’ player 9 staff and players highlighted that increased awareness of player safety over the years has led to a decrease in the overall exposure, and increased level of control, of contact training sessions, leaving them feeling that they are already doing the minimal amount of contact training necessary (sub-theme 1.2). this opinion contradicts the findings of previous research in the same population, which reports no significant changes in contact training time over an 11-season period.[10] ‘i don't know how much more we could reduce it be able to go into the weekend confident.’ player 10 in recent years, some contact sports have seen limits placed on the volume and frequency of contact training permitted in a season by their governing bodies [e.g. national football league (nfl), canadian football league (cfl)]. when the possibility of implementing similar in-season constraints was explored with participants in this study, they were conceptually supportive, provided the limits still enabled the necessary contact exposure for appropriate development (sub-theme 1.2) and an individualised approach (sub-theme 1.3). currently, the national governing body of clubs participating in this study enforces a mandatory five-week no contact training post-season period. when participants were asked about extending the length of that period, several concerns were raised. participants highlighted that a lack of exposure to contact for an extended time may result in deconditioning and subsequently an increased risk for injury (sub-theme 1.2). in professional rugby, a greater frequency and burden of training injuries is observed in the early period of the preseason, immediately following the 5-week offseason.[22] the outbreak of the coronavirus pandemic resulted in disruptions to the 2019-20 english premiership rugby season and players were subjected to 12-weeks of restricted training.[23] when players returned to team training, a significantly higher incidence of training injury was observed in comparison to that following a regular 5-week offseason.[23] although players would typically have access to more training facilities during a regular off-season than they did during this 12-week period, the findings provide some support to the participants’ concerns that an extended period of not training specific skills, namely, those that require interaction with other players, may result in deconditioning and a subsequent increased risk for injury.[23] it is likely an individualised approach to training and recovery is required. ‘it’s rest, but it’s also detraining. you’ve got to be careful of making that too long, because doing some progressive contact is a form of injury prevention, and coaching technique is a form of injury prevention.’ staff 4 participants also stressed that developing contact conditioning safely requires a progressive build up and if insufficient time was afforded before the first match of the season, a rapid increase in contact exposure would pose a risk to players (subtheme 1.1). in professional rugby, rapid increases and large changes in week-to-week training load have been associated with increased injury risk [17] and while this applies to the total load and not the contact load specifically, the principles may be the same. the increased risk of injury observed following the coronavirus-induced suspension of the season[23] appeared to be mitigated by the time competition resumed, with the match injury incidence comparable to the regular season.[23] a 10-week progressed training period was implemented before match play resumed and suggests that an appropriate and progressive return to training may assist in mitigating an increased risk of injury associated with an extended time away from regular match play and team training.[23] ‘if you're going to put a minimum amount of time you've got to have off then you probably need to think about a maximum amount of time before the contact and how you bridge to that intensity’ staff 9 3.2. there are no reliable and practical methods of collecting objective contact data the feasibility of collecting objective contact data was discussed in the staff focus group sessions. several barriers to the collection of objective contact data were identified by staff participants. a few clubs indicated that they have been trialling imgs, but this data is yet to inform practise sessions due to a lack of understanding and/or confidence in the metrics they produce. ‘we've looked at different parameters and talked to different s&c coaches around the clubs and there isn't anything tangible that i would put my confidence in to then talk to the coaches about.’ staff 19 human resources were also identified as a barrier, with the collection of head impact exposure-related data considered an additional time burden on already busy staff. it is important to note that the only club using data from imgs to inform contact training prescription had a sports scientist directly linked to the mouthguard provider embedded within the club. this individual was responsible for managing the collection and analysis of img data and, having a significant understanding of the metrics produced, was able to work alongside coaching original research sajsm vol. 34 no.1 2022 8 staff to translate the data to practically relevant changes to the contact training schedule. ‘…it's something that would be good but the burden at the moment to collect all that information and i also don't think [we] have microtechnology that actually quantifies it correctly.’ staff 7 conclusion this study has identified a varied understanding of what constitutes head impact exposure and the activities that contribute to the greatest magnitude and frequency of exposure across a diverse range of stakeholders in elite rugby. the absence of available research on head impact exposure was a catalyst to conducting this study and the findings confirm that there is a real knowledge gap in the rugby community. a strength of this study is its diversity of participants, exposing that varied knowledge is apparent across medical, conditioning, coaching, player, and research departments at the highest level of rugby. subjectivity will always be present in coaching, load prescription and player management; therefore, exploring subjective views on the topic is essential. the sequential mixed-methods design of the present study was a strength-based approach, with triangulation of data producing substantiated findings and participant feedback providing credibility to the research outputs. the absence of objective data to inform understanding of head impact exposure has resulted in different opinions and consequently varied management strategies have emerged. most notable were the different views on specific elements relating to head impact exposure amongst players compared to staff. players typically interpreted training activities to have a higher potential for head impact than staff and, while staff suggested the incorporation of padded equipment would make training safer, players viewed this as potentially increasing the level of risk. there were also mixed interpretations of how best to conduct training for technical development, while limiting head impact exposure, with some participants indicating these sessions are best achieved through training in controlled environments and others indicating that repeated efforts in match-like environments are necessary. yet, participants felt that they have already limited the amount of full contact training to the perceived minimum necessary amount, and that no further decrease is possible. these findings show that individuals within clubs have different interpretations of head impact exposure, resulting in sometimes contradicting management techniques. to promote open communication, player focus groups were held separately from staff sessions. nonetheless, it is probable that the format of having all staff from each club present during one online session may have made it harder for some staff to communicate freely than if sessions had been guided 1-2-1 or in-person. coronavirus-induced constraints on conducting in-person research, combined with time constraints on participants, with this study being conducted during the final rounds of the season, meant that the options of formats for conducting focus group sessions were limited. these limits may partly explain the low response rate seen in round 2 of the study. it is difficult to implement change and inform practice when individuals have varied perceptions about a subject and this becomes a greater challenge when there is limited objective data available to support any changes. there is a need for objective data to identify activities with a high risk for head impact exposure and possible unintended consequences of reduced exposure to these activities. the rugby football union, the governing body of the teams involved in this study, has committed itself to make instrumented mouthguards available to all players competing in the upcoming english premiership season as a result of this work, in order to gather objective impact data and advance knowledge on this subject. as data and knowledge on head impact exposure develop, this must be accompanied with knowledge exchange within the rugby community. even with objective data available, training prescription will always contain an element of subjectivity and as such, knowledge exchange amongst practitioners will be essential to develop safe but effective training practices. rugby union is a complex landscape with a diverse range of stakeholders involved in policy development and practise, thus research needs to be combined with expertise and experience from all stakeholder groups to develop practical solutions to generate change in this area. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors would like to express their considerable gratitude to christian day (rpa) for recruiting the players and assisting in the facilitation of this study with them, as well as duncan locke (rfu) for his support in compiling the video material and questionnaires. the authors would also like to thank the club staff and players involved in this study for their eagerness to participate and incredible valuable contributions. author contributions: all authors contributed to the inception and design of the study. ls led the analysis and interpretation of data and initial writing of the manuscript, with input from cm and ks. all other authors provided significant feedback and comments in refining the final manuscript. references 1. west sw, starling l, kemp s, et al. trends in match injury risk in professional male rugby union: a 16-season review of 10 851 match injuries in the english premiership (2002-2019): the professional rugby injury surveillance project. br j sports med; 55(12): 676-682. [doi:10.1136/bjsports-2020-102529] [pmid: 25115142] 2. west s, cross m, trewartha g, et al. trends in match concussion incidence and return-to-play time in male professional rugby union: a 16-season prospective cohort study. brain inj 2021;35(10):1235-1244. [doi:10.1080/02699052.2021.1972142] 3. cross m, kemp s, smith a, et al. professional rugby union players have a 60% greater risk of time loss injury after concussion: a 2-season prospective study of clinical outcomes. br j sports med 2016;50(15):926-931. [doi:10.1136/bjsports-2015094982][pmid: 26626266] original research 9 sajsm vol. 34 no.1 2022 4. manley g, gardner aj, schneider kj, et al. a systematic review of potential long-term effects of sport-related concussion. br j sports med 2017;51(12):969-977. [doi:10.1136/bjsports-2017097791] [pmid: 28455362] 5. stokes ka, locke d, roberts s, et al. does reducing the height of the tackle through law change in elite men’s rugby union (the championship, england) reduce the incidence of concussion? a controlled study in 126 games. br j sports med 2021;55(4):220-225. [doi:10.1136/bjsports-2019-101557] 6. tucker r, raftery m, kemp s, et al. risk factors for head injury events in professional rugby union: a video analysis of 464 head injury events to inform proposed injury prevention strategies. br j sports med 2017;51(15):1152-1157. [doi:10.1136/bjsports-2017-097895] [pmid: 28642222] 7. attwood mj, roberts sp, trewartha g, et al. efficacy of a movement control injury prevention programme in adult men’s community rugby union: a cluster randomised controlled trial. br j sports med 2018;52(6):368-374. 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[doi:10.1080/02640414.2019.1692415] [pmid: 31755824] 11. creswell j. research design: qualitative, quantitative, and mixed-methods approaches. 2nd ed. thousand oaks, ca: sage publications, 2003. 12. harris pa, taylor r, minor bl, et al. the redcap consortium: building an international community of software platform partners. j biomed inform 2019;95:103208. [doi:10.1016/j.jbi.2019.103208] [pmid: 31078660] 13. nowell ls, norris jm, white de, et al. thematic analysis: striving to meet the trustworthiness criteria. int j qual methods 2017;16(1):1-13. [doi:10.1177/1609406917733847] 14. braun v, clarke v. using thematic analysis in psychology. qual res psychol 2006;3(2):77-101. [doi:10.1191/1478088706qp063oa] 15. diamond ir, grant rc, feldman bm, et al. defining consensus: a systematic review recommends methodologic criteria for reporting of delphi studies. j clin epidemiol 2014;67(4):401-409. [doi:10.1016/j.jclinepi.2013.12.002] [pmid: 24581294] 16. attride-stirling j. thematic networks: an analysis tool for qualitative research. qual res 2001;1(3):385-405. [doi:10.1177/146879410100100307] 17. cross mj, williams s, trewartha g, et al. the influence of inseason training loads on injury risk in professional rugby union. int j sports physiol perform 2016;11(3):350-355. [doi:10.1123/ijspp.2015-0187] [pmid: 26309331] 18. tierney gj, denvir k, farrell g, et al. the effect of tackler technique on head injury assessment risk in elite rugby union. med sci sports exerc 2018;50(3):603-608. [doi:10.1249/mss.0000000000001461] [pmid: 29049096] 19. davidow d, quarrie k, viljoen w, et al. tackle technique of rugby union players during head impact tackles compared to injury free tackles. j sci med sport 2018;21(10):1025-1031. [doi:10.1016/j.jsams.2018.04.003] [pmid: 29803736] 20. tierney gj, denvir k, farrell g, et al. the effect of technique on tackle gainline success outcomes in elite level rugby union. int j sport sci coach 2018;13(1):16-25.[doi:10.1177/1747954117711866] 21. williams em, petrie fj, pennington tn, et al. sex differences in neck strength and head impact kinematics in university rugby union players. eur j sport sci 2021, oct 28:1-10. [doi:10.1080/17461391.2021.1973573] [pmid: 34463209] 22. stokes ka, jones b, bennett m, et al. returning to play after prolonged training restrictions in professional collision sports. int j sports med 2020;41(13):895-911. [doi:10.1055/a-1180-3692] [pmid: 32483768] 23. starling lt, mckay c, cross m, et al. prolonged restricted training, fixture congestion and player rotation: what the covid-19 pandemic taught us about injury risk in professional collision sport. j sci med sport 2022;25:480-485. [doi:10.1016/j.jsams.2022.03.012] original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the epidemiology of injury and illness amongst athletes at the indian ocean island games, mauritius, 2019 d garnett,1,2 mphil; a bholah,3 mbbs, msc; b olivier,4 phd; j patricios,5 mbbch ffsem (uk); y d’hotman,3 bs physiotherapy; k sunassee,3 mmed, msc; s cobbing,1 phd 1 physiotherapy department, college of health sciences, university of kwazulu natal, durban, south africa 2 department of physiotherapy, faculty of health sciences, university of pretoria, pretoria, south africa 3 comité d’organisation de la 10ème edition des jeux des iles de l’océan indien, mauritius 4 physiotherapy department, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 5 wits sport and health (wish), school of clinical medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: d garnett (danielphysio@gmail.com) the 10th indian ocean island games (ioig) were held in mauritius from 19-28 july 2019. this multi-sport event occurs every four years between participating athletes from seven of the indian ocean islands, namely, comoros, reunion, mayotte, madagascar, maldives, seychelles, and mauritius. the 14 sporting codes represented included football, basketball, rugby sevens, judo, table tennis, volleyball, beach volleyball, swimming, yachting, weightlifting, boxing, athletics, cycling and badminton. in almost half a century of competition, no previous injury or illness research has been conducted for this event, and little is known of how injuries in these athletes compare to athletes in other parts of the world. surveillance studies towards improving athlete welfare are supported by the international olympic committee (ioc), and they allow a snapshot of current injuries and illness, which are essential in the preparation of future events.[1] injury surveillance during similar sporting events have been documented using standardised injury reporting since the 2004 olympic games in athens.[2] the incidence of injury at both the summer and winter olympic games appears to be increasing,[2-8] apart from the rio games, where compliance in reporting by medical staff was unaccountably lower than recent studies (74% in rio, 99.7% in sochi and 96% in london).[5-6] interestingly, the incidence of athletic injury and illness varied substantially between the different sporting codes over the same period. this finding calls for bespoke prevention strategies tailored to the differing demands placed on the athletes of the specific sports.[2-5] this planning should also include strategies to support athletes when exposed to different climates. specific to this study are the warm and humid conditions of the tropical island of mauritius. this research is novel as it is the first such project that captures the injury and illness data from all athletes participating at the indian ocean island games – a first in the games’ 40year history and a first for sports in this tropical region – as well as comparing these data to other international research. continued surveillance of injury and illness at subsequent indian ocean island games will allow the establishment of customised and relevant prevention strategies to enhance athlete welfare in this region. methods study design and setting the study design was a prospective surveillance study of injuries and illnesses occurring during the indian ocean island games (ioig) 2019 on the mauritius island. the definitions and methodologies are described in detail in this manuscript and have been adopted from similar previous research to allow for the comparison of results as per recommendations by these authors.[2,5,9] background: the indian ocean island games is a multi-sport event that occurs every four years and includes athletes from seven islands of the indian ocean, namely, comoros, reunion, mayotte, madagascar, maldives, seychelles, and mauritius. objectives: this study aims to describe the injury and illness epidemiology of the athletes participating during the 2019 indian ocean islands games. methods: this prospective cohort study recorded injury and illness cases from athletes who competed in these games. all medical physicians received detailed instructions and training on data collection using an injury report form. all athletes (minors and adults) who provided consent, or consent given from the minors’ guardians, were included in this study. athletes who did not provide consent for this study were excluded. results: athletes (n = 1 521; 531 women and 990 men) reported 160 injuries (injury incidence rate of 11%) and 85 illnesses (illness incidence rate of 6%). the percentage of distribution of injuries were highest in football and basketball. most injuries occurred during competition, compared with training, joint sprains were the most common type of injury (28%), followed by muscle strains (19%). men suffered most of the injuries (79% vs. 21% for women). similarly, men sustained more illnesses than women (57% vs. 43%). most illnesses affected the respiratory system (67%), and infection was the most common cause of illness (84%) in participating athletes. conclusion: these findings are similar to previous events in other parts of the world. however, unique ailments, not previously reported on, were discovered. epidemiological data from this study can be inferred to athletes who compete in similar multisport events in the indian ocean region. keywords: surveillance, prevalence, incidences, elite athletes, prevention, multi-sports s afr j sports med 2021;33:1-7. doi: 10.17159/2078-516x/2021/v33i1a11211 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a11211 https://orcid.org/0000-0003-4630-0028 https://orcid.org/0000-0002-0620-0658 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0001-9287-8301 https://orcid.org/0000-0001-5669-6121 https://orcid.org/0000-0003-0794-7873 https://orcid.org/0000-0002-4507-579x original research sajsm vol. 33 no. 1 2021 2 ethical considerations permission to conduct the research study was granted by the games local organising committee, namely the comite d’organisation de la 10eme edition des jeux des iles de l’ocean indien (coji 2019). ethical clearance was obtained from mauritian and south african research ethics committees (brec: recip471/19/ wits: m190444). informed consent was obtained from the respective team authorities and all individual participants included in the study. athletes who were considered minors gave informed assent and informed consent were obtained from their respective guardians. athletes who did not wish to participate or did not provide informed consent were excluded. all forms were translated and presented in french and english. participants all athletes were provided with study information packs on registration and invited to participate in the research study. all data were coded to protect confidentiality and ensure privacy. all athletes had access to identical treatment, whether part of the research study or not. injury report form the research instrument was the injury report form (appendix a), which was a simple single page form with references and further information on the back of the form. sections of the injury reporting form included:  accreditation number which detailed anthropometric and demographic data of athletes.  injury injury type, cause of injury, date, time and site of injury, injured body part and cause.  illness diagnosis, affected system, main symptom(s), probable cause.  severity of injury or illness time out of competition or training calculated in days.  sports and event type as described by the technical department of comité d’organisation de la 10ème edition des jeux des iles de l’océan indien (coji) in 2019. definitions an injury was defined as any new musculoskeletal complaint that occurred during competition or training within the period of the tournament and that received medical attention, regardless of the consequences concerning absence from competition or training. this injury definition includes five aspects: (i) all injuries that received medical attention, (ii) newly incurred injuries, (iii) injuries occurring during competition or training, (iv) injuries occurring during the period of the tournament, and (v) exclusion of other illnesses and diseases.[1,4,9] all injuries and illnesses were coded to ensure a standard injury or illness definition. an illness was defined as any physical symptom that required medical attention or prevented an athlete from taking part in training and competition.[10] procedures the sports federations and medical representatives of all participating countries were requested to participate and were electronically provided with information regarding the study one month before the ioig. all host nation medical staff received training on the completion of the injury report form in training ahead of the ioig. on the eve of the ioig, all visiting physicians responsible for athletes received a printed booklet with information about the study and attended a pre-study workshop. during this meeting, the aims of the study were presented, practical components discussed, the roles and responsibilities defined, and the contact details of the research team were provided. detailed instructions on how to complete the injury reporting form were given, with examples, on how to report an athlete’s injury and/or illness.[1,7,9] thus, all injuries and illnesses at the ioig were diagnosed and reported by qualified and trained medical personnel to ensure valid information was provided regarding the characteristics of the injury and to allow a comparable standard of data. the researchers conducted injury surveillance over 11 days (19-28 july 2019). during the tournament, members of the research team visited the medical physicians of the respective countries at the team hotels to ensure compliance and discuss any problems that they may have encountered. the sequence of daily data collection procedures included the following six steps; step 1: a single injury reporting form was completed for every injury that was presented to each doctor (team and local). thus, a single participant could have had multiple forms for polytrauma events. step 2: the completed forms were collected by the principal researcher and scanned for missing information. step 3: if possible, errors discussed with the reporting physician, and if there were no errors, double entries were identified. step 4: if there were double entries, then the team physician’s form would be used. step 5: data were captured onto a password encrypted electronic form on a password accessed computer. step 6: completed hard copy forms were placed into a password-protected safe to ensure the anonymity of participants. statistical analysis in cases where an injury or illness was duplicated in reporting by the ioig medical teams and team physicians, the most complete data source was retained.[3] the illness and injury incidences (i) were calculated according to the formula i = n/e, where n is the number of injuries or illnesses in competition or training and e is the total number of participating athletes during the total study period of 11 days. descriptive data was captured from the hard copies to electronic format for coding using microsoft excel software. statistical analysis was performed using graphpad prism 9.1.2 software and checked by a statistician from university of kwazulu-natal. results participants in total, 1 521 athletes were registered for the competition; this included 531 women and 990 men. the ages of the athletes ranged from 1059 years (mean: 25.2 years). the average age of female athletes was 23.8 years (range 10.2 59.5 years) and 25.9 years for male athletes (12.6 57.2). original research 3 sajsm vol. 33 no. 1 2021 incidence of injury the 1 521 athletes sustained a total of 160 injuries, resulting in an injury incidence rate of 10.5% (10.5 injuries per 100 athletes) (table 1). most injuries occurred during competition when compared with training (57% vs. 43%). most of the injuries were suffered by male athletes (79% vs. 21%). injury location and type the percentage of the body region most frequently injured was the lower limb (63%), followed by the upper limb (21%), and head/torso (16%). the most common sites of injury were the thigh (20%), followed by the knee (18%), calf (11%), shoulder (9%), and ankle (8%) (table 2). the most common types of injury reported were joint sprains (28%), muscle strains (19%), muscle cramps or spasms (16%), contusions/haematomas (13%), lacerations (9%), tendinosis/tendinopathies (5%), concussions (3%), fractures (3%), other bone injuries (2%), ligamentous ruptures (1%), arthritis/synovitis/ bursitis (1%), dental injuries (1%) and other injuries (1%). injury mechanisms and circumstances the mechanism of a sustained injury was most commonly due to contact with other athletes (collisions) (28%), overuse with sudden onset of injury (19%), non-contact trauma (17%), overuse with gradual onset (17%), contact with a stagnant object (8%), contact with a moving object (5%), recurrence of previous injuries (3%), violation of rules (3%), field of play conditions (1%), and a player being tackled (1%). tacklers, being the defending players without possession of the ball, had no reported injuries (0%). illness distribution and the affected system the 1 521 athletes reported a total of 85 illnesses, resulting in an illness incidence of 6% (6 illnesses per 100 athletes). the respiratory system was the most affected system as shown in table 3. overall, men reported more illnesses than women (57% vs. 43%). the most frequently reported cause of illness in athletes was infection (84%), followed by environmental causes (5%), pre-existing conditions (5%), exercise-induced (4%), others (2%), and reaction to medication (1%). table 1. distribution of injuries and illnesses in all athletes per sport at the indian ocean island games (ioig) 2019 sport injuries illnesses all athletes (n = 160) male (n = 127) female (n = 33) all athletes (n = 85) male (n = 49) female (n = 36) football 38 (24) 38 (24) 0 (0) 7 (8) 6 (7) 1 (1) basketball 23 (14) 13 (8) 10 (6) 5 (6) 2 (2) 3 (4) athletics 18 (11) 14 (9) 4 (3) 18 (21) 9 (11) 9 (11) volleyball 18 (11) 13 (8) 5 (3) 13 (15) 7 (8) 6 (7) judo 13 (8) 7 (4) 6 (4) 1 (1) 0 (0) 1 (1) rugby 7’s 13 (8) 13 (8) 0 (0) 6 (7) 6 (7) 0 (0) sailing 9 (6) 8 (5) 1 (<1) 3 (4) 2 (3) 1 (1) badminton 8 (5) 5 (3) 3 (2) 6 (7) 3(4) 3 (4) boxing 8 (5) 8 (5) 0 (0) 7 (8) 6 (7) 1 (1) weightlifting 4 (3) 2 (1) 2 (1) 6 (7) 3 (4) 3 (4) table tennis 2 (1) 1 (<1) 1 (<1) 6 (7) 2 (3) 4 (5) cycling 2 (1) 2 (1) 0 (0) 1 (1) 1 (1) 0 (0) swimming 2 (1) 2 (1) 0 (0) 6 (7) 2 (3) 4 (5) beach volleyball 2 (1) 1 (<1) 1 (<1) 0 (0) 0 (0) 0 (0) data are expressed as n (%). table 2. injury location of athletes at the indian ocean island games (ioig) 2019 body region or part all athletes (n = 160) males (n = 126) females (n = 34) lower limb 100 (63) 81 (51) 19 (12) upper limb 34 (21) 24 (15) 10 (6) head/torso 26 (16) 21 (13) 5 (3) thigh 32 (20) 29 (18) 3 (2) knee 29 (18) 19 (12) 10 (6) calf 18 (11) 16 (10) 2 (1) shoulder 15 (9) 8 (5) 7 (4) ankle 13 (8) 9 (6) 4 (3) lower back 8 (5) 6 (4) 2 (1) face 7 (4) 6 (4) 1 (<1) hand 6 (4) 5 (3) 1 (<1) thumb 5 (3) 5 (3) 0 (0) neck 4 (3) 4 (3) 0 (0) finger 4 (3) 4 (3) 0 (0) head 4 (3) 3 (2) 1 (<1) foot 4 (3) 3 (2) 1 (<1) elbow 3 (2) 1 (<1) 2 (1) upper arm 2 (1) 2 (1) 0 (0) achilles tendon 1 (<1) 1 (<1) 0 (0) groin 1 (<1) 1 (<1) 0 (0) hip 1 (<1) 1 (<1) 0 (0) pelvis 1 (<1) 1 (<1) 0 (0) thoracic region 1 (<1) 1 (<1) 0 (0) abdomen 1 (<1) 1 (<1) 0 (0) data are expressed as n (%). original research sajsm vol. 33 no. 1 2021 4 discussion the primary finding of this research is that the injury incidence was 10.5 injuries sustained per 100 athletes, and 6 illnesses sustained per 100 athletes. as this was the initial study, no previous ioig data were available for direct comparison. thus, injury data from previous surveillance research by the international olympic committee (ioc) were used to allow comparison of similar athletes at multievent tournaments over a fixed study period using similar methods. furthermore, ioig illness data were compared to the olympic games’ surveillance studies since 2010, as this was the first official ioc commencement of methodology to include illness surveillance. incidences of injury the overall incidence of injury to athletes at ioig 2019 is comparable to previously reported injuries at beijing, vancouver, london, and rio games and a lower injury incidence at the sochi and pyeongchang games (fig.1).[3-8] the weather in mauritius is similar to that experienced in the summer olympic games, when data is compared from similar sporting codes. the incidence of injury is similar at the ioig 2019 (10.5 injuries sustained per 100 athletes vs. 8-11 injuries sustained per 100 athletes) when compared with the winter olympic games (10-12 injuries sustained per 100 athletes).[4,6,8] however, male athletes suffered more injuries than female athletes at the ioig 2019, in contrast to previous findings from the winter olympic games in vancouver 2010, sochi 2014 and pyeongchang 2018.[4,6,8] the vastly different nature of the sporting codes at the ioig and summer olympic games versus the winter olympic games may account for some of these differences, [3-8] but serial research at future ioigs is required in order to identify accurate trends. injury location and circumstances the distribution of injuries during competition and training at ioig was similar to previous studies in the summer olympic games (table 4).[5, 7] however; they are contrast to the winter olympic games, where training injuries were higher than competition injuries (table 4). [4,6,8] the most common sites of injury at the ioig 2019 were similar to previous studies for vancouver 2010 (head 19-20%; knee 10-16%), rio 2016 (knee 12%; thigh 10%) and pyeongchang 2018 (knee 14%; ankle 9%).[4,7,8] a clear indication shows the knee being the most injured site during all olympic games tournaments over the past decade, possibly due to large rotational demands placed on a primarily hinge-type joint.[10] this valuable information allows for focused knee injury prevention initiatives for participating athletes. type and cause of injuries at the ioig 2019, the three most common causes of injury were similar with previous results from beijing 2008, vancouver 2010, london 2012, sochi 2014, and rio 2016 (table 4).[3-7] in pyeongchang 2018, the most common cause of injury was contact with a stagnant object and non-contact trauma. this is similar to previous winter olympic games, which may be an indication of the local conditions of the host venues and specific equipment required for these games.[4,6,8] for example, these conditions may add an element of risk not seen in other venues. vancouver had many injuries with stagnant objects in the bobsleigh run and skiing/snowboarding slopes, and sochi had many injuries caused by the snowboard halfpipe.[4] the nature of these sports necessitate a low friction coefficient of ‘playing’ surfaces and conveys an increased risk of injury. interestingly, at ioig 2019 in mauritius in a tropical climate, ‘marine coral’ was identified as “field of play conditions’ which resulted in lacerations of the lower leg and feet of some of the athletes. statistical analysis of these injury data was performed using pearson’s correlation (p=0.05, 95% ci). the values were significant for most of the olympic games except for sochi 2014 (beijing p=0.0162; vancouver p=0.0464; london p =0.0053; sochi p=0.2096; rio p=0.0003; pyeongchang p=0.0349). caution should be exercised when interpreting these results as different methodologies between studies resulted in the item “contact table 3. distribution of athlete illness affected systems at the indian ocean island games (ioig) 2019 affected system all athletes (n = 85) males (n = 49) females (n = 36) respiratory 57 (67) 36 (42) 21 (25) gastrointestinal 15 (18) 11 (13) 4 (5) dermatologic 5 (6) 0 (0) 5 (6) cardiovascular 4 (5) 1 (1) 3 (4) allergic 1 (1) 0 (0) 1 (1) metabolic 1 (1) 0 (0) 1 (1) neurologic 1 (1) 0 (0) 1 (1) dental 1 (1) 1(1) 0 (0) data are expressed as n (%). fig. 1. incidence of injury at previous olympic games[3-8] and the indian ocean island games (ioig) 2019 original research 5 sajsm vol. 33 no. 1 2021 with another athlete” not being available as an option for injury mechanism/cause in pyeongchang 2018.[8] knowledge and awareness of concussion have improved significantly over the past decade,[11-13] and effective preventative strategies such as protective equipment may account for the lower number of reported concussions during ioig 2019. this incidence falls within the mid-range (range = 0.06% 0.8%) of previously reported research in beijing, vancouver, london, sochi, rio and pyeongchang. [3-8] incidence and distribution of illnesses the overall incidence of illness to athletes at ioig 2019 is lower than previously reported at studies at the olympic games as shown in table 5.[4-6,8] however, in contrast to previous olympic games, men reported more illness than women at ioig.[5-8] although it is important to identify that more male athletes were included in the study, than female athletes. most athlete illnesses affected the respiratory and gastrointestinal systems, corresponding to previous winter and summer olympic games (range 47-70% respiratory system; 13-21% gastrointestinal system).[4-8] interestingly, a trend is forming with higher infection rates and respiratory illness at the winter olympic games. the winter conditions exposed participating athletes to vastly different external factors than the weather conditions in mauritius in 2019. the risk of upper respiratory tract illness may be increased from repeated cold air exposure and supports the higher incidence resulting from exercise-induced or environmental factors in the winter olympic games, compared to ioig.[14,15] in contrast, infection was the most common cause of illness at ioig 2019. this was significantly higher than previously reported studies,[4-8] and may be representative of the humid tropical environment that the athletes were exposed to. statistical analysis of illness data was performed using pearson’s correlation (p=0.05, 95% ci). the values were significant for all olympic games, except for london 2010 (beijing no illness data collected; vancouver p=0.0136; london p=0.0849; sochi p=0.0394; rio p=0.0319; pyeongchang p=0.0183). when comparing the sports at the summer olympic games, the incidence of illness varied substantially between sporting codes. athletes participating in track-and-field events reported significantly more illnesses than in previous summer olympic games in london (7%) and rio (6%) respectively.[5,7] by contrast, illnesses for footballers was lower at the ioig 2019 than during the london and rio games (8% vs. 12% and 12% respectively).[5,7] limitations there are limitations to the methodology of this study that are common to previous similar research. attending medical staff and athletes may not have engaged and participated in the research as intended. measures to improve compliance by explaining the benefits of the research were utilised. however, many athletes were not accustomed to medical research procedures, and some athletes chose not to participate in the study. although research study information was supplied both electronically and in printed form to the international sporting federations, the authors are unsure whether this information was disseminated to all athletes. furthermore, the compliance of medical staff to complete the injury reporting forms effectively could not be guaranteed as it placed an additional administrative burden on their clinical duties. previous injuries or illnesses were not accounted for and could be a factor to table 4. injury characteristics for participating athletes cause of injury beijing 2008 vancouver 2010 london 2012 sochi 2014 rio 2016 pyeongchang 2018 ioig 2019 contact with another athlete 33 15 14 28 28 non-contact trauma 20 23 20 13 21 18 17 overuse with sudden onset 13 25 19 19 contact with a stagnant object 22 25 31 concussion 0.11 0.8 0.06 0.4 0.11 0.17 0.26 injured during competition 73 46 55 35 59 46 57 injured during training 25 54 45 63 37 48 43 data are expressed as % of participating athletes at each games[3-8]. ioig, indian ocean island games; -, data not available. table 5. incidence and distribution of illnesses beijing 2008 vancouver 2010 london 2012 sochi 2014 rio 2016 pyeongchang 2018 ioig 2019 illness incidence 7 7 8 5 9 6 respiratory illness 62 41 64 47 70 67 gastrointestinal illness 20 16 11 21 13 18 illness for females 60 64 59 60 44 illness for males 40 36 41 40 56 infection 64 46 58 56 63 84 data are expressed as % of participating athletes at each games[3-8]. ioig, indian ocean island games; -, data not available. illness incidence (i) is calculated as i = n/e, where n is the number of illnesses in competition or training and e is the total number of participating athletes during the total study period of 11 days original research sajsm vol. 33 no. 1 2021 6 consider in future studies. lastly, small changes in reporting methodology by different host nations and local organising committees in previous studies may result in data that is not entirely comparable. recommendations this research presents the first account of mechanisms and contexts of injuries and the incidences and distribution of illnesses in the 40-year history of the ioig. the information on the mechanisms and contexts for the injuries and illnesses allows for the evaluation of the 2019 medical services and guides of future organising committees of the ioig to ensure the most beneficial allocation of resources. this unique setting exposes athletes to conditions not seen in other parts of the world where some conditions may be beneficial or harmful to the athletes. the continued collection of data at these games will allow more precise preparation for multi-event sporting competitions that will be unique to the region. to ensure greater research clarity, athlete understanding, and improved athlete participation, future studies of this nature in this region should explore alternative methods of information sharing that include electronic/social media/app or peerbased methods. furthermore, future studies should allow sufficient budgeting and allocation of resources to enable medical administrators to act as dedicated data capturers in order to ensure a higher standard of compliance and data collection. conclusion an injury and illness surveillance system for multiple sports events was adapted from recent olympic games, and developed and implemented for the 10th indian ocean island games held in mauritius in 2019. this was the first study to report on the epidemiology of injuries and illnesses at these games and provides important information for the planning of subsequent multi-national multi-sport events in this region. just over ten percent (10.5%) of all athletes sustained an injury and 6% sustained an illness during the games, similar to the information from recent olympic games. continued analyses of illness risk factors and injury mechanisms are essential to direct future athlete welfare policies. early recommendations encourage further research in developing injury prevention programmes to safeguard the needs of the athlete and prevent illnesses by reducing infections to the upper respiratory tract. this study is the first step in developing informed injury and illness prevention initiatives to allow athletes to perform at their highest level while minimising their health risks, and comes at a time of heightened awareness and need to reduce respiratory illness. key points  emerging data from this established traditional tournament reveal novel insights into the athletes of the indian ocean.  a trend is forming showing how elite athletes display similar rates of illnesses and injuries in multi-sport events in different regions of the world.  future studies are recommended to specifically assess the unique risk factors to individual regions to better prepare athletes and the medical teams who support these athletes. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. availability of data and material: the datasets generated used and/or analysed during the current study are available from the corresponding author on reasonable request. acknowledgements: the authors would like to acknowledge that this research would not have been possible without the support of the mauritian government, coji local organising committee, local and international medical teams and the participating athletes. author contributions: all authors contributed to (i) conception, design, analysis, and interpretation of data; (ii) drafting or critical revision for important intellectual content; and (iii) approval of the version to be published. references 1. junge a, engebretsen l, alonso jm, et al. injury surveillance in multi-sport events: the international olympic committee approach. br j sports med 2008; 42(6): 413-421. 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[doi: 10.1016/j.rmed.2008.09.011][pmid: 18977127] 15. d’amato m, molino a, calabrese g, et al. the impact of cold on the respiratory tract and its consequences to respiratory health. clin transl allergy 2018;8(1):1-8. [doi: 10.1186/s13601018-0208-9] original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license female cricket pace bowling: kinematic and anthropometric relationships with ball release speed c lyons,1 bsc; pj felton,2 phd, fhea; c mccabe,1 phd, sfhea 1 school of sport, ulster university, belfast, northern ireland 2 school of science & technology, nottingham trent university, england corresponding author: c mccabe (c.mccabe@ulster.ac.uk) cricket is a sport played between two teams where players assume batting, bowling, or fielding roles which dictate their main responsibilities within a game. a bowler’s primary objective is to dismiss the batters on the opposing team and restrict the number of runs they score. pace bowlers aim to dismiss batters by maximising their ball release speed (brs) and decreasing the time they have to react to the delivery of the ball and execute the correct shot.[1] research in pace bowling has therefore focused on investigating variables associated with brs to inform coaching practice.[1-11] previous studies have investigated the impact on brs of kinematic variables including the run-up,[1–4] the front leg kinematics,[1,3,5–7] the motion of the thorax,[1,3,6,7] and the position of the bowling arm.[1,3,7] the bowlers with the fastest brs have exhibited faster run-up speeds, as well as straighter front knee kinematics, more trunk flexion and delayed arm circumduction from front foot contact to ball release. the effect of anthropometric parameters on brs have also been investigated with variables including limb length, body composition, height, and mass.[2,8–11] positive associations have been reported between limb length and height with longer levers associated with increased angular velocities and subsequent brs.[2,8–11] despite previous research investigating the relationships between kinematic and anthropometric variables with brs, the findings are almost exclusively derived from male populations. although female participation and professionalism has increased in recent years, there remains a lack of research into female cricket.[12] early research comparing male and female pace bowling biomechanics has found differences in ball release speed, run-up speed, and the kinematics at back foot contact, front foot contact and ball release.[13] these findings suggest females may utilise a different movement pattern to generate brs compared to males, and that extrapolating information from research conducted on male pace bowlers to coach female pace bowlers is potentially erroneous.[14] nevertheless, coaches working with female pace bowlers are restricted due to the current coaching pedagogy being derived on studies conducted using male bowlers. this study therefore aims to investigate whether previously reported kinematic and anthropometric relationships with brs in male pace bowlers exist for female pace bowlers. methods participants eleven high performance female pace bowlers participated in this study. all bowlers were right-handed and senior members of either irish international or interprovincial team members. the testing procedures (as approved by the ulster university research ethics committee) were explained to all bowlers, health history screening questionnaires were completed, and informed consent was obtained. prior to data collection, all bowlers were deemed fit to bowl and a thorough warm-up was conducted allowing participants to familiarise themselves with the testing environment. data collection kinematic data were collected at an indoor facility where bowlers were able to use a full length run-up to deliver a 141,75 g female cricket ball on a standard sized cricket pitch. sixteen tape markers (20 x 20 mm) were placed bilaterally on the acromion, olecranon, mid-point of the thoracic cage (approximately t8), anterior superior iliac spine, lateral malleolus, medial malleolus, the carpus, and the armpit of each participant. six maximal effort deliveries targeted at a good length were recorded using two iphone 11 video recorders (apple inc, california, usa) capturing at 240 hz. each iphone was mounted on a tripod at a height of 0.91 m and placed 6 m background: despite an increase in the professionalism and participation of female cricket, the coaching of female pace bowling is still reliant on male-derived knowledge. objectives: to investigate the association between key malederived kinematic and anthropometric parameters and ball release speed (brs) in female pace bowlers. methods: eleven female pace bowlers participated in this study. brs, and four anthropometric and five kinematic parameters were determined. stepwise linear regression and pearson product moment correlations were used to identify anthropometric and kinematic parameters linked to brs. results: the best predictor of brs explaining 89% of the observed variance was the bowling shoulder angle at ball release. the best anthropometric predictor of brs was height explaining 53% of the observed variance. other parameters correlated with brs included: run-up speed (r = 0.75, p = 0.013) and arm length (r = 0.61, p = 0.046). when height was controlled for, the front knee angle at front foot contact was also correlated to brs (r = 0.68, p = 0.044). no relationship was found between trunk flexion and brs. conclusion: faster brs were characterised by faster run-up speeds, straighter front knees, and delayed arm circumduction similar to male pace bowlers. the lack of relationship between trunk flexion and brs may highlight female pace bowlers adopting a bowling technique where brs is contributed to by trunk rotation as well as trunk flexion. this knowledge is likely to be useful in the talent identification and coaching of female pace bowlers. keywords: fast bowling, technique, size, shoulder, height s afr j sports med 2023;35:1-5. doi: 10.17159/2078-516x/2023/v35i1a15080 mailto:c.mccabe@ulster.ac.uk http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15080 https://orcid.org/0000-0001-9211-0319 https://orcid.org/0000-0002-1184-6461 https://orcid.org/0000-0002-8964-3074 original research sajsm vol. 35 no.1 2023 2 perpendicular to the sagittal plane on either side of the bowling crease, so the optical axis aligned with the plane of motion of the bowler during the delivery.[5] a batter was not involved to prevent distraction from bowling with maximal effort,[4] but a target was placed on a good length.[2] between deliveries bowlers were instructed to rest until they felt ready to bowl another delivery at maximal effort.[8] brs was measured using a radar gun (bushnell, 10-1911, usa) positioned 2 m behind the stumps at the bowler’s end. runup speed was determined using two pairs of photocell timing gates (tci system, brower timing systems, utah, usa). each pair of timing gates was set to hip height (approximately 1 m) and placed 5 m apart (0.5 and 5.5 metres behind the bowling crease). four anthropometric measurements were also taken. height (m) and weight (kg) were recorded using a stadiometer and digital scales respectively, as well as front leg and bowling arm length (m). leg length was measured from the anterior superior iliac spine to the lateral malleolus, and arm length from the acromion process to the tip of the digitus medius. data analysis the variation in brs and each of the four kinematic parameters (run-up speed, front knee angle at ffc, shoulder angle at br, and trunk flexion from ffc to br) was assessed using analysis of variance (anova). the between-trial variability was compared with the between-bowler variability and was found to be much smaller with interclass correlation coefficients (icc) ranging from 0.81 to 1.00 (mean: 0.92). the three deliveries were consequently averaged for each kinematic parameter to provide representative data for each bowler and put forward for statistical analysis.[1] statistical analysis all statistical analyses were performed within spss v.28 (spss corporation, usa). an alpha value of 0.05 was used as a threshold for significance with no adjustment made for multiple comparisons due to the investigatory nature of the study.[15] forward stepwise linear regressions were used to identify the anthropometric and kinematic (independent) variables which best explained the variation in brs (dependent variable). pearson’s product moment correlation was used to identify ‘candidate’ variables for input into the regression models with an alpha value below 0.05 required for selection. to ensure all potential candidate variables were identified, kinematic variables were also eligible for selection if pearson’s product moment correlation alpha values were below 0.05 when anthropometric candidate variables were used as a covariate. predictor variables included in the two individual regression models (anthropometric and kinematic) were put forward as candidate variables to an overall regression model. entry requirements for the inclusion of a parameter into the regression equation was p < 0.05, with a removal coefficient of p > 0.10. the regression model was rejected if the coefficient 95% confident intervals included zero, the residuals of the predictor were heteroscedastic or if the bivariate correlations, tolerance statistics or variance inflation factors showed any evidence of multicollinearity.[16] the normality of the standardised residuals was also confirmed by the shapiro-wilk test. the percentage variance of the dependent variables (brs) explained by the independent (kinematic) variables in each regression equation was determined by wherry’s r2 value.[17] this represents an attempt to estimate the proportion of the variance that would be explained by the model had it been derived from the population (elite female fast bowlers) from which the sample was taken. to overcome the potential limitations of stepwise regressions relying on a single best fit model, all possible regression models with the same number of predictor variables were checked. results the 11 bowlers (age: 22.3 ± 4.7 years; height: 1.68 ± 0.08 m; mass: 73.0 ± 8.3 kg) produced mean brs of 23.0 ± 1.8 m.s-1 in the range: 20.3 26.4 m.s-1. descriptive data are reported in table 1. two anthropometric (height and arm length) and two kinematic parameters (run-up velocity and shoulder angle at br) were found to be linearly correlated with brs (table 2) and used as candidate variables for the linear regression models. a further kinematic parameter (knee angle at br) was added as a candidate variable after a linear correlation was observed for brs when anthropometric candidate variables were controlled for (table 2). the candidate variables were investigated for multicollinearity using bivariate correlations. since arm length was observed to be significantly correlated with height with a pearson’s correlation coefficient greater than 0.80 it was removed as a candidate variable.[16] all other significant correlations between candidate variables were below 0.80 and were deemed suitable for entry in the forward stepwise linear regression models. the best anthropometric predictor of brs was height explaining 53% of the variation in brs (table 3, figure 1a). greater height characterised the bowlers with the faster brs. no other candidate variables qualified for entry into the anthropometric regression equation. the best kinematic predictor of brs was the shoulder angle at br explaining 89% of the variation (table 3, figure 1b). a more delayed bowling table 1. kinematic and anthropometric parameters: range, mean, standard deviation (n=11) parameter mean ± sd range anthropometric leg length (m) 0.90 ± 0.08 0.73 1.00 arm length (m) 0.71 ± 0.05 0.64 0.82 kinematic run-up velocity (m.s-1) 5.05 ± 0.61 3.72 5.77 front knee angle at ffc (°) 167.0 ± 2.9 160.7 171.4 bowling shoulder angle at br (°) 180.3 ± 7.7 172.7 194.4 trunk flexion from ffc to br (°) 43.5 ± 8.5 24.4 57.2 ffc, front foot contact; br, ball release original research 3 sajsm vol. 35 no.1 2023 arm (greater shoulder angle) at br characterised the bowlers with the highest brs. the best overall model predicting brs mirrored the kinematic model with only shoulder angle at br entered. a two-parameter model was found when both height and shoulder angle at br were included in the regression equation (table 3); however, this was rejected due to the height coefficient 95% confidence interval including zero. discussion the study aimed to investigate whether previously reported kinematic and anthropometric relationships with brs in male pace bowlers exist for female pace bowlers. the most important parameter with respect to increasing brs was the bowling shoulder angle at br. the fastest bowlers had their arm further back relative to their upper trunk at br. this aligns with male research which also identifies the shoulder angle at br to be the best predictor of brs.[1] a more delayed bowling arm has been proposed to allow greater amounts of trunk flexion, while still allowing the arm to deliver the ball towards the intended target.[7] consequently, increased trunk flexion has also been linked to greater brs in male pace bowlers.[1,3,7] no relationship, however, was observed between brs and trunk flexion from ffc to br in this study. female pace bowlers have previously been reported to have longer trunks than their male counterparts.[11] in theory, longer trunks have larger transverse moments of inertia increasing the resistance of the trunk to flex or extend about the pelvis. previous research has suggested that female bowlers generate brs using a more rotational technique than males,[13] where a combination of trunk flexion and rotation contribute to the delay in the bowling arm. further research is required therefore to understand the role of trunk flexion and rotation throughout the bowling action and how this affects delayed arm circumduction in female pace bowlers. the best anthropometric predictor of brs was height. the tallest bowlers in this study benefited from an anthropometric effect which aided their generation of brs. a taller stature has previously been identified as a benefit to male brs since the longer and heavier segments help increase angular velocity and brs.[2] the positive correlation between arm length and brs found in this study and reported in previous male pace bowling research[2,10] also aligns with this theoretical explanation. nevertheless, care should be exerted when applying this knowledge. theoretically, taller players need to generate more power to move their longer and heavier segments at similar speeds to their shorter counterparts. this relationship is not linear and therefore optima exist where the increase in size cannot be overcome by an increase in muscle power, and brs is negatively impacted. in other words, bigger is not continuously better, and there is a tipping point based on the ability to maintain the power to weight ratio. table 2. bivariate and partial correlations between brs and the anthropometric and kinematic parameters (n=11) parameters r 95% ci p lower upper bivariate correlations anthropometric height (m) 0.76 0.29 0.93 0.007 mass (kg) 0.07 -0.56 0.64 0.85 leg length (m) 0.24 -0.42 0.73 0.48 arm length (m) 0.61 0.02 0.89 0.05 kinematic run-up velocity (m.s-1) 0.75 0.22 0.94 0.01 front knee angle at ffc (°) 0.49 -0.16 0.84 0.13 bowling shoulder angle at br (°) 0.95 0.82 0.99 <0.001 trunk flexion from ffc to br (°) -0.19 -0.71 0.46 0.57 partial correlations covariate: height run-up velocity (m.s-1) 0.41 -0.58 0.80 0.28 front knee angle at ffc (°) 0.68 0.18 0.98 0.04 bowling shoulder angle at br (°) 0.94 0.77 0.99 <0.001 trunk flexion from ffc to br (°) -0.05 -0.86 0.93 0.90 covariate: arm length run-up velocity (m.s-1) 0.60 -0.42 0.88 0.09 front knee angle at ffc (°) 0.67 -0.28 0.99 0.05 bowling shoulder angle at br (°) 0.94 0.74 0.99 <0.001 trunk flexion from ffc to br (°) -0.07 -0.94 0.77 0.87 ffc, front foot contact; br, ball release; ci, confidence interval table 3. forward stepwise linear regression models predicting ball release speed (n=11) model candidate variables coefficient 95% ci p explained variation (%) lower upper anthropometric height (m) 17.379 5.429 29.329 0.010 53 constant -6.361 -26.578 13.855 0.489 kinematic shoulder angle at br (°) 0.224 0.168 0.279 <0.001 89 constant -17.294 -27.280 -7.308 0.004 overall height (m) 5.776 -0.068 11.621 0.052 93 shoulder angle at br (°) 0.185 0.125 0.246 <0.001 constant -20.131 -29.014 -11.247 <0.001 br, ball release; ci, confidence interval original research sajsm vol. 35 no.1 2023 4 contrary to previous male derived findings,[2] no significant association was identified between leg length and brs for the female pace bowlers in this study. differences in body composition between males and females may explain this. female pace bowlers have been reported to have shorter legs compared to male pace bowlers.[11] the role of the lower half of the body in generating brs in pace bowling is to brake the pelvis, converting the linear momentum developed in the run-up into angular momentum about the centre of mass.[1] the optimal technique for converting linear momentum to angular momentum is to adopt a straight front leg.[1,7] in this study, greater run-up speeds and straighter front knee angles at ffc (when height was controlled for) were associated with increased brs. these findings are similar to those previously observed in male pace bowlers.[1–7] the mean run-up speed (5.05 m.s-1) is slightly slower than those previously observed (females: 5.31 m.s-1; males: 5.76 m.s-1) [13];however, this difference is likely to be a consequence of adopting a different measurement approach and limits comparison. increased run-up speeds were also associated with taller bowlers and the association between run-up speed and brs was weakened when height was controlled for. this indicates that individual-specific optimal run-up speeds exist and are most likely based on height. future investigations exploring brs may need to control for height (or a similar anthropometric parameter) if the participants' anthropometric parameters are not homogeneous. no relationship between brs and body mass was observed in this study. although using body mass can be misleading, due to large variations in underlying variables,[18] no relationships between brs and the measurements of fat mass, bone mass, muscle mass, and body composition have been observed in male pace bowlers.[9] while the findings of this study suggest the relationship between brs and body mass is similar for males and females, it has been proposed that differences in body composition may cause the gender gap in brs.[12] while understanding this was beyond the scope of this study, it is recommended that future studies investigate more detailed anthropometric measures and their effect on technique as well as brs. this study has some limitations. firstly, the sample size of eleven female pace bowlers (while still relatively large for this population) limits the power of the statistical tests conducted. secondly, the two dimensional analysis employed due to the testing environment are secondary in terms of accuracy to more complex three dimensional approaches available in the laboratory. finally, the aim of this investigation was to determine whether relationships between kinematic variables previously linked to brs in male fast bowlers exist in female pace bowlers. a greater number of kinematic parameters are required to fully appreciate the characteristics of technique which influence brs in female pace bowling. while the findings of this study indicate some alignment between male and female pace bowling techniques to maximise brs, this may occur due to female pace bowlers being coached based on male pace bowling philosophy, and not because this is the optimal method to generate brs for female pace bowlers. further research is required to understand the optimal technique to maximise brs in female pace bowlers, ideally using three dimensional motion capture and sample size with large statistical power. conclusion in conclusion, this study investigated whether kinematic and anthropometric relationships with brs in female pace bowlers are similar to those previously reported in male pace bowlers. the findings highlight that greater brs were characterised by increased height and larger bowling shoulder angles at br. in addition, evidence highlighted relationships between greater brs and straighter front knee angles at ffc and run-up speed. fig. 1. predicted ball release speed against actual ball release speed for: (a) the anthropometric regression model and (b) the kinematic regression model. with a higher percentage of the variation in ball release speed explained the closer the data points lie to the dashed line y = x (predicted ball release speed = actual ball release speed). original research 5 sajsm vol. 35 no.1 2023 while these relationships are similar to those observed in male pace bowlers, the lack of a relationship between trunk flexion and brs in this study may add evidence to the theory that trunk rotation is important in developing brs in female pace bowlers. this study also highlighted the relationship between height and run-up speed, as well as brs, indicating that each individual will have an optimal run-up speed, and a potential brs ceiling based on their height. these findings are likely to be extremely useful in the development of knowledge regarding female pace bowling, especially coaching and talent identification. future research should aim to build on these findings adopting more complex methodologies and larger sample sizes to improve statistical power in order to develop cause and effect relationships for the female pace bowling action. in particular, understanding the role of trunk rotation and flexion of bowling shoulder arm delay and the generation of brs. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: all authors provided a substantial contribution to the conception, design, analysis, and interpretation of this data. in addition, substantial contributions were made to the drafting and approval of this manuscript. references 1. worthington pj, king ma, ranson ca. relationships between fast bowling technique and ball release speed in cricket. j appl biomech 2013;29(1):78-84. [doi:10.1123/jab.29.1.78] [pmid: 22813926] 2. glazier ps, paradisis gp, cooper sm. anthropometric and kinematic influences on release speed in men’s fast-medium bowling. j sports sci 2000;18(12):1013-1021. [doi:10.1080/026404100446810] [pmid: 11138981] 3. elliott bc, foster dh, gray s. biomechanical and physical factors influencing fast bowling. aust j sci med sport 1986;18(1):16-21. 4. salter cw, sinclair pj, portus mr. the associations between fast bowling technique and ball release speed: a pilot study of the within-bowler and between-bowler approaches. j sports sci 2007;25(11):1279-1285. [doi:10.1080/02640410601096822] [pmid: 17654240] 5. loram lc, mckinon w, wormgoor s, et al. determinants of ball release speed in schoolboy fast-medium bowlers in cricket. j sports med phys fitness 2005;45(4):483-490. [pmid: 16446679] 6. portus mr, mason br, elliott bc, et al. technique factors related to ball release speed and trunk injuries in high performance cricket fast bowlers. sports biomech 2004;3(2):263-284. [doi:10.1080/14763140408522845] [pmid: 15552585] 7. felton pj, yeadon mr, king ma. optimising the front foot contact phase of the cricket fast bowling action. j sports sci 2020;38(18):2054-2062. [doi:10.1080/02640414.2020.1770407] [pmid: 32475221] 8. pyne db, duthie gm, saunders pu, et al. anthropometric and strength correlates of fast bowling speed in junior and senior cricketers. j strength cond res 2006;20(3):620-626. [doi:10.1519/r18315.1] [pmid: 16937976] 9. wormgoor s, harden l, mckinon w. anthropometric, biomechanical, and isokinetic strength predictors of ball release speed in high-performance cricket fast bowlers. j sports sci 2010;28(9):957-965. [doi:10.1080/02640411003774537] [pmid: 20552518] 10. singh k, singh r. relationship of selected anthropometric variables with throwing distance of cricket ball in cricket. j appl res 2015;4(8):1-6. 11. stuelcken m, pyne d, sinclair p. anthropometric characteristics of elite cricket fast bowlers. j sports sci 2007;25(14):1587-1597. [doi:10.1080/02640410701275185] [pmid: 17852680] 12. munro ce, christie cj. research directions for the enhancement of women's cricket. int j sports sci coach 2018;13(5):708-712. [doi:10.1177/1747954118764102] 13. felton pj, lister sl, worthington pj, et al. comparison of biomechanical characteristics between male and female elite fast bowlers. j sports sci 2019;37(6):665-670. [doi:10.1080/02640414.2018.1522700] [pmid: 30244646] 14. emmonds s, heyward o, jones b. the challenge of applying and undertaking research in female sport. sports med open 2019;5:51. [doi:10.1186/s40798-019-0224-x] [pmid: 31832880] 15. sinclair j, taylor pj, hobbs sj. alpha level adjustments for multiple dependent variable analyses and their applicability a review. int j sports sci eng 2013;7(1):17-20. 16. field a. discovering statistics using ibm spss statistics. 4th ed. london: sage, 2013. 17. wherry rj. a new formula for predicting the shrinkage of the coefficient of multiple correlation. ann math statist 1931;2(4):440457. [https://www.jstor.org/stable/2957681] 18. prentice am, jebb sa. beyond body mass index. obes rev 2001;2(3):141-147. [doi:10.1046/j.1467-789x.2001.00031.x] [pmid: 12120099] original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license team approach to osteoarthritis management: viewpoints of biokineticists and physiotherapists in south africa r gilchrist, ma; a kholvadia, phd department of human movement science, faculty of health sciences, nelson mandela university, gqeberha, south africa, 6001 corresponding author: r gilchrist (s214051196@mandela.ac.za) there are challenges within the south african healthcare system when providing the appropriate continuum of care to address the complexities of patients with osteoarthritis (oa).[1] the burden and complexity of the disease, the influence of poverty, infrastructure challenges, lack of resources and funding for rehabilitation, and staff shortages[1] create a substantial strain on the healthcare platform. furthermore, collaborative systems in oa have several impediments to care, including restrictions in access to healthcare services, communication deficiencies, unfamiliarity with the roles of healthcare professionals (hcps), lack of knowledge by hcps, and inequities in care.[2] collaborative practice is a typical feature of oa care with treatment provided by a range of allied and medical professionals, and the patients themselves.[2] the scope of practice (sop) of biokinetics and physiotherapy is ideally suited to oa management[3] as set out by the health professions council of south africa’s (hpcsa) professional board for physiotherapy, podiatry, and biokinetics.[4] the sop of both professions, as stipulated by the hpcsa, allows for the prescription of rehabilitative exercises.[4] previous research[5] clarified the overlap in exercise prescription between the two professions by stating how acute symptomatic treatment of chronic conditions, such as oa, involves acute phase mobilisation and manipulation by physiotherapists. the publication mentioned above later stated that if surgery is warranted, the patient may undergo acute phase physiotherapy initially, followed by sub-acute phase physiotherapy to control pain and disability.[4,5] in accordance with recommended clinical guidelines for oa,[3] referral to a biokineticist for final phase functional exercises should then occur at week six of the rehabilitation plan[5] to assist the patient to return to functional activities of daily living.[3,6] thus therapeutic exercise and symptom relief treatment modalities offered by biokineticists and physiotherapists are important for optimal oa management,[3] particularly as evidence shows a favourable effect compared with sedentary individuals.[7-9] the above research highlights the indispensable role each profession plays in the management of oa at the different phases of the rehabilitation process. the therapeutic and rehabilitative nature of both professions at different phases of oa management highlight a complex interaction which emphasises the need for a coordinated approach among different professions to achieve effective outcomes for the patient. this notion is supported by research which indicates that a team of hcps can effectively deliver optimal patient-focused care,[8,10] which is a holistic approach to individualised care compared to the traditional biomedical model of medicine that regards the patient as a disease carrier requiring diagnosis and treatment.[8] such holistic care addresses the multidimensional needs of oa patients by allowing the patient to play an active role in their healthcare[2,11] and has the potential to improve the quality of their healthcare.[2] local researchers [5] have iterated the effectiveness of healthcare teams internationally, stating how physiotherapists, clinical exercise physiologists and personal trainers practice alongside each other in the united states of america. similarly in europe, physiotherapists, clinical exercise physiologists and kinesiotherapists cross-refer patients to one another.[5] national studies[12,13] have reported that such an background: the rehabilitative nature of biokinetics and physiotherapy in osteoarthritis management highlights a complex interaction between different professions to achieve effective outcomes for the patient. the success of a team approach is dependent on key competencies for optimal patient-focused care and appropriate cross-referral systems. objectives: to explore and describe the viewpoints of biokineticists and physiotherapists regarding a team approach to osteoarthritis management in the south african public and private healthcare setting. methods: a descriptive methodology with a convenience sampling technique was used. the target population consisted of biokineticists (n=47) and physiotherapists (n=165) located within the south african healthcare sectors. a selfadministered, online questionnaire surveyed rehabilitative professionals’ views of a team approach to osteoarthritis management. results: there is no evidence that the biokineticists and physiotherapists differ with respect to how they rate the communication between team members in osteoarthritis management (p=0.68). communication was viewed as neither of a high nor low quality by biokineticists (43%) and physiotherapists (36%). biokineticists (54%) and physiotherapists (69%) felt adequately equipped on their understanding of the role of various healthcare professions involved in osteoarthritis management (p=0.22). however, 43% of rehabilitative professionals indicated that they had not been exposed to interprofessional education initiatives (p=0.61). conclusion: both professions were well-versed on the roles of various professions involved in osteoarthritis management, however, communication was not optimal. while this study creates an awareness of the benefits of team-based management for osteoarthritis, the findings could stimulate debate on the optimal implementation of key competencies required for effective teamwork, thereby facilitating patientfocused care and referral systems. keywords: biokinetics, chronic disease management, healthcare teams, interprofessional education, physiotherapy s afr j sports med 2023;35:1-7. doi: 10.17159/2078-516x/2023/v35i1a15260 mailto:s214051196@mandela.ac.za http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15260 https://orcid.org/0000-0002-2870-4953 https://orcid.org/0000-0002-1650-6116 original research sajsm vol. 35 no.1 2023 2 approach to patient care has been linked to positive perceptions of healthcare management by patients[12] and improved patient compliance with rehabilitation.[13] further south african-based research; however, has reported that oa is managed with a combination of conservative and surgical interventions that demonstrate considerable variations in costs, utilisation of interventions, and access to care.[7,9,12] the varied nature of oa care[14] is not only less effective for some patients, but potentially more expensive due to duplicate and sub-optimal treatment.[8] models that incorporate a team approach may mitigate these concerns, thereby facilitating improved patient outcomes and redistribution of oa management costs.[8] the success of a team approach is dependent on positive perceptions among individual hcps.[15] these perceptions are formed by the hcp’s knowledge regarding each profession’s sop.[15] however, a lack of familiarity with the services offered by and the roles of various disciplines often leads to poor engagement and uptake of a team approach.[5] a local study[15] reported that the perceptions among various disciplines were mainly negative as a result of a lack of knowledge around other professions’ roles, thereby hindering a collaborative environment.[15] an unawareness of other professions’ sop may have implications for patient-focused care and may lead to grey areas in terms of rehabilitation jurisdiction[5] and crossreferrals. further contributing to the success of a team approach is effective communication among all the members of the healthcare team.[16] clear communication strategies will ensure the implementation of key components required for patient-focused care, such as well-ordered transitions between rehabilitation areas, sharing of relevant information and education, coordination and continuity of care, and outcomes that are important to the patient.[16] conversely, ineffective communication creates uneasiness, doubt and dissatisfaction with patient care, and has been linked to a lack of compliance with recommended treatment options by patients.[17] furthermore, ineffective communication has also been linked to increased stress, lack of job satisfaction and emotional burnout among hcps.[17] in order to foster a team environment, there needs to be clear communication, positive perceptions and a greater awareness among hcps.[12] positive perceptions of different hcps are developed during formal academic training through interprofessional education (ipe), thus creating an awareness and environment for organised healthcare teams.[12,18] there are four key competencies that address collaboration within healthcare teams.[18] these competencies include: values and ethics for collaborative practice, knowledge of one’s own role and responsibility and those of other professions, communication among patients, families, communities, and professionals, and teamwork.[18] the emersion within these competencies has been identified as critical for the provision of efficient healthcare, given the complexity of patients' healthcare needs and the range of hcps involved.[15] numerous studies[15,19,20] have explored the perceptions of various hcps towards each other; however, no studies have described rehabilitative professionals’ views on a team approach to oa management in the south african healthcare setting. furthermore, there is a dearth of published oa research in south africa with identified gaps in the continuum of the care pathway for the management of oa.[12] therefore, the purpose of this study was to explore and describe the viewpoints of various biokineticists and physiotherapists regarding a team approach to oa management in the south african public and private healthcare setting. awareness of the diverse and multidisciplinary nature of oa care and rehabilitative professionals’ views of a team approach to oa care could guide best practice recommendations and strategies to enhance organised teamwork to promote service delivery and quality person-focused care for the oa patient in south africa. methods study design a descriptive, cross-sectional survey research design was used in this study. the design utilised quantitative data collected initially to explore and describe the viewpoints of biokineticists and physiotherapists regarding a team approach to oa management. participants the target population consisted of biokineticists and physiotherapists who have worked with or are currently working with an oa patient population within either the public and/or private healthcare sectors. gatekeepers from healthcare profession associations were approached, and permission to invite volunteers to be part of the study was granted. the associations included the biokinetics association of south africa, the south african society of physiotherapy, and the south african sports medicine association. participants were recruited using a convenience sampling technique whereby the gatekeepers of the respective associations emailed the hcps via their online practitioner database. the email included a description of the study and a link to the study’s online questionnaire. within this description it stated that the study was specific to oa management and participants were required to have worked with or are currently working with such a patient population. thereby, prospective participants were excluded if they were not involved in oa management, if they were not registered with the hpcsa, or if they were students or interns. ethical clearance was provided by the nelson mandela university research ethics committee: human (h20hea-hms005). data collection data were collected using a closed-ended online questionnaire (supplementary data). the questionnaire was designed by the principal investigator, guided by a group of multidisciplinary academics within the faculty of health sciences, following a structured review of the literature. a panel of subject experts (including academics and hcps) then reviewed and edited the questionnaire. the link for the online questionnaire was distributed via email by the gatekeepers of the associations to members of the statutory bodies. questionpro® was the software used to capture, distribute and analyse the descriptive original research 3 sajsm vol. 35 no.1 2023 data. all participants could complete the questionnaire anonymously. thereby informed consent was provided by selecting the link to access the questionnaire. questions were designed to prompt for the selection of answers from a list of options with some questions adopting a likert-type scale. the questionnaire was circulated for a period of six months. the complete questionnaire that was circulated consisted of the following sections: (i) descriptive data in terms of the number of years in practice, from which healthcare sector participants practised, and their current practice setting; and (ii) participants’ ratings of various factors that influence teambased oa management. these factors were based on the ipe competencies, the questions included: to describe the communication between hcps in the oa management team, identification of the knowledge of one’s own role and responsibility, and those of other members within the oa healthcare team, and finally, to explore their stance on interprofessional engagement and teamwork for oa management in south africa. statistical analysis quantitative, descriptive data were exported from questionpro® to microsoft excel spreadsheets for coding purposes. statistical analysis was performed using the statistical package for social science (spss) version 26.0 (ibm corp. 2019. ibm spss statistics for windows, version 26.0. armonk, ny: ibm corp). data were presented as frequencies and percentage distributions for categorical data. cross tabulations, together with chi-square analyses, were performed to quantitatively analyse the relationship between biokineticists and physiotherapists and their rating of a team approach in oa management. significant results (p<0.05) were emphasised. results descriptive data the descriptive data of the participating hcps are shown in table 1. the study cohort comprised of 212 participants of which 47 were biokineticists and 165 were physiotherapists. data showed that biokineticists and physiotherapists differ with respect to the number of years they have been in practice (p=0.04). when evaluating the data distribution among the physiotherapist participants, an even distribution of years in practice was noted. however, among the cohort of biokineticists, 66% of participants indicated that they had been in practice for 10 years or less. additionally, there is evidence that the biokineticists and physiotherapists differ with respect to which healthcare sector they practice from (p<0.001). results show that the majority of the physiotherapists (82%) practiced solely in the private healthcare sector, with 12% in the public healthcare sector, whereas 66% of biokineticists practiced in private healthcare or a combination of private and public (19%) or private and corporate (9%) sectors. table 1 further illustrates the current practice setting of biokineticists and physiotherapists. a number of physiotherapists described their practice setting within a hospital and/or clinic (32%) or as a solo practice (33%). biokineticists strongly favoured solo practices (55%). it can be concluded that there is evidence that the biokineticists and physiotherapists differ with respect to their current practice set-up (p=0.002). table 1. descriptive data of healthcare professionals (n=212) frequency (%) profession physiotherapy 165 (78) biokinetics 47 (22) frequency (%) chi-square p-value physiotherapists biokineticists number of years in practice 8.18 0.04* < 6 years 40 (24) 16 (34) 6-10 years 40 (24) 15 (32) 11-20 years 44 (27) 13 (28) >20 years 41 (25) 3 (6) healthcare sector currently practicing from 18.02 <0.001* public sector 20 (12) 3 (6) private sector 135 (82) 31 (66) combination public and private sector 7 (4) 9 (19) combination of private and corporate sector 3 (2) 4 (9) current practice setting 14.82 0.002* solo practice 55 (33) 26 (55) partnership practice with a practitioner in the same discipline as myself 43 (26) 11 (23) partnership practice with a practitioner in a complementary discipline to myself 15 (9) 7 (15) practice is within a hospital / clinic setting 52 (32) 3 (6) data are expressed as n (%). * indicates p<0.05. original research sajsm vol. 35 no.1 2023 4 team approach in osteoarthritis management table 2 indicates biokineticists’ and physiotherapists’ rating of a team approach to oa management. there is no evidence that the biokineticists and physiotherapists differ with respect to how they rate the overall communication between team members (p=0.68). communication was viewed as neither of a high nor low quality by biokineticists (43%) and physiotherapists (36%). respectively, 54% and 69% of the biokineticists and physiotherapists felt adequately equipped on their understanding of the sop of various healthcare professions involved in oa management. there is, however, no evidence that the biokineticists and physiotherapists differ with respect to how they rate their competence regarding their knowledge of the various sops (p=0.22). there is evidence, however, that the biokineticists and physiotherapists differ with respect to how they rate interprofessional engagement (p=0.003). interprofessional engagement was viewed as extremely important among the study biokineticists (57%), whereas the physiotherapists rated interprofessional engagement very (56%) to somewhat important (12%) in the rehabilitation of an oa patient. there is no evidence of a difference between the exposure of ipe during the training of biokineticists and physiotherapists (p=0.61), with 43% of participating professionals indicating that they had not been exposed to ipe initiatives. finally, the majority of the biokineticists (93%) and physiotherapists (91%) agreed that the south african healthcare system would benefit from structured healthcare teams. discussion the aim of this study was to explore and describe the viewpoints of biokineticists and physiotherapists regarding a team approach to oa management. based on the ipe competencies required for effective teamwork in healthcare, the major findings of this study reported that communication in the oa management team was viewed as neither of a high nor low quality among hcps. furthermore, the participating biokineticists and physiotherapists felt adequately equipped on their understanding of the sop of various healthcare professions involved in oa management; however, a large number of these professionals indicated that they had not been exposed to ipe initiatives. the cohort of physiotherapists in this study reported a range of experience in practice, whereas, a larger number of biokineticists reported practicing for less than 10 years. unlike physiotherapy, biokinetics is the latest addition to the rehabilitative professions group, and this descriptive finding table 2. rating team-based osteoarthritis management in a south african landscape frequency (%) chi-square p-value physiotherapists (n=163) biokineticists (n=47) overall communication between team members 2.30 0.68 very high quality 13 (8) 6 (13) high quality 46 (28) 10 (21) neither high nor low quality 59 (36) 20 (43) low quality 35 (21) 9 (19) very low quality 10 (6) 2 (4) knowledge of the scope of practice of various healthcare professions 5.76 0.22 extremely familiar 23 (14) 5 (11) very familiar 90 (55) 20 (43) somewhat familiar 40 (25) 17 (36) not so familiar 8 (5) 5 (11) not at all familiar 2 (1) 0 (0) importance of interprofessional engagement 11.55 0.003* extremely important 55 (32) 27 (57) very important 92 (56) 19 (40) somewhat important 20 (12) 1 (2) not so important 0 (0) 0 (0) exposure to interprofessional education 0.26 0.61 yes 93 (57) 25 (53) no 69 (43) 22 (47) stance on healthcare teams in a south african landscape 2.91 0.41 extremely important 105 (64) 35(74) very important 44 (27) 9 (19) somewhat important 11 (7) 3 (6) not so important 5 (3) 0 (0) data are expressed as n (%). * indicates p<0.05. original research 5 sajsm vol. 35 no.1 2023 can be supported by the gain in popularity in recent years and the subsequent recognition of the profession of biokinetics in the south african healthcare system.[4,5] the majority of both professional groups reported practicing in the private healthcare sector. the demand for rehabilitative professions, such as biokinetics and physiotherapy in both the public and private healthcare sectors, is evident based on the rise of noncommunicable diseases, including oa, in south africa.[1,6] the need for biokinetics in the public sector has received growing attention in recent years; however, lack of resources and funding for rehabilitation still proves to be considerable barriers.[1] the effectiveness of healthcare teams globally has been highlighted in the literature,[5,11] particularly in the management of oa as this condition is well suited to this model given the input required from multiple disciplines to meet the broad needs of these patients.[8] a team approach focused on outcomes that matter to patients may optimise patient outcomes,[8] improve perceptions of healthcare management by patients,[12] increase patient compliance with rehabilitation,[13] and redistribute interventional costs.[8] there is, therefore, calls to establish these teams in south africa.[7,12,15] nonetheless, the current study reported that solo practices were the favoured practice setting for both biokineticists and physiotherapists, with both profession groups further favouring partnership practices with a professional in the same discipline. care provided by a single professional group may fail to address the complexity of oa patient needs,[2] thereby being less successful and potentially more expensive because of unnecessary or inappropriate interventions.[2,8,12] poor patient outcomes could lead to decreased patient compliance with rehabilitation.[13] mlenzana and frantz[16] stated that the success of a team approach is dependent on effective communication among all members of the healthcare team. effective communication was not found to be present in the results of the study as the data showed that communication was viewed as neither of a high nor low quality by a large number of rehabilitative professionals. ineffective communication has been noted in the literature, especially regarding oa care,[2,12] and has significant implications for patient outcomes.[2,8,17] numerous studies have demonstrated that better communication methods improve decision quality, confidence, satisfaction and compliance with intervention options, and professional patient engagement.[8,17] key aspects in the improvement of the practical nature of patient-focused care include information transfer between hcps, shared decisionmaking[18] and listening to the needs of the patient.[2] these communication practicalities can be supported during the implementation phase by advocating for sufficient consultation time which allows the patient to feel heard by discussing their overall healthcare needs and actively engaging with their hcp regarding their treatment plan.[2,12] furthermore, virtual communication pathways, such as telehealth and/or interoperable electronic health record systems, increase patients’ and professionals’ reachability and information transfer.[2] such virtual communication methods may prove valuable and consistent when used in conjunction with a communication framework established through ipe interventions which may enhance the capacity of hcps to deliver improved coordinated care.[2,18] therefore, this output advocates for education initiatives for improved communication methods between members of the oa healthcare team. in addition to effective communication, collaborative interactions stem from positive perceptions among hcps.[15,19,20] positive perceptions are attained through an understanding of discipline-specific roles.[15] the current study reported that the participating biokineticists and physiotherapists felt adequately equipped regarding their understanding of the sop of various healthcare professions involved in oa management. a promising finding when compared to previous research which found no evidence of the knowledge that physiotherapists may have regarding biokineticists and other allied professionals.[15] moreover, this understanding of the sop of the various healthcare disciplines encourages interprofessional engagement.[5, 15] this study, however, suggests that while both biokineticists and physiotherapists identified the importance of interprofessional engagement, the study’s biokineticists were more in favour of interprofessional engagement when compared to the physiotherapists. interestingly, a study by ellapen et al.[15] agrees by stating that biokineticists were favourably inclined to interprofessional engagement compared to physiotherapists, who were more apprehensive towards collaborative relations owing to their perception that these professionals were trespassing on their sop. it is, therefore, important to address previous opinions of fragmented healthcare experiences among hcps in order to strengthen both the therapeutic alliance and health outcomes for the patients. emphasis should be placed on this level of appreciation and awareness of other hcps’ roles and responsibilities[5] to facilitate team-based management, and thereby guide appropriate referral pathways and interventions. to accomplish this, literature has supported the notion that the implementation of ipe, as a vehicle for efficient collaborative engagement, should be promoted beyond a tertiary level[15] and become an essential component of a healthcare team’s continuing professional training.[18] healthcare professional associations are perfectly positioned to begin instituting quarterly roadshows and workshops to encourage interprofessional collaboration and education strategies among hcps in practice. this educational setting would shape team identity, add to relational therapy skills, increase the understanding of different rehabilitation phases, and reduce misperceptions of the different professions’ roles.[18] the importance of ipe to team functioning and healthcare provision prompted the researchers to identify the exposure to ipe among the study’s participants. the results showed that a large number of the participating professionals had not been exposed to ipe during their training. to make better use of interventional costs,[8] the establishment of appropriate referral pathways[15] and collaborative relations, and to more effectively meet the complex needs of oa patients,[2] it is essential that healthcare educational and organisational systems prioritise ipe initiatives. original research sajsm vol. 35 no.1 2023 6 limitations and recommendations for future research while the cohort of participants was limited, future studies should aim at contributing to this research on a larger scale and elaborate on rehabilitative professionals as pivotal members of the healthcare team. that said, this study only included two rehabilitative profession groups, which is not wholly representative of a complete healthcare team. additionally, the study sample excluded students and interns. therefore the most current investigation of educational practices may have been beyond the scope of the study. conclusion the study showed that both professions were well-versed in the sop of each of the members involved in the oa management team; however, communication among members was not optimal. the key ipe competencies for the promotion of a team approach to patient-focused care are stressed in the concluding remarks of this research. interprofessional education is one way to improve the functioning of hcps within a team and engagement with these competencies is critical to the provision of efficient healthcare. therefore, while this study creates an awareness of the benefits of team-based management of oa, the findings could stimulate further debate on the optimal implementation of the key competencies required for effective communication and teamwork, thereby facilitating patient-focused care and the appropriate referral systems. furthermore, this study aimed to contribute to the paucity of research concerning rehabilitative professionals’ views of a team approach and highlight the importance of their respective roles in oa management, which may contribute to the mutual appreciation of the different professions, thus preventing trespassing on the sop of other professions and calling attention to the need for a team approach in clinical practice. conflict of interest and source of funding: the authors declare that they have no conflict of interest. funding for this study has been provided by the national research foundation (nrf). opinions expressed, and conclusions arrived at are those of the authors and are not necessarily attributed to the nrf. acknowledgements: the authors would like to thank the nrf and institution for the financial support and the participants, without whom this study would not have been possible. author contributions: rg was involved in the conception, design, analysis and interpretation of the data, and the drafting of the manuscript. ak was involved in the 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[https://doi.org/10.1080/16070658.2012.11734427] original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license the core of performance in adolescent cricket pace bowlers: trunk muscle stability, maybe, but not strength-endurance and thickness fm olivier,1,2 msc; b olivier,1,2 phd; n mnguni,1 bhsc hon 1 wits cricket research hub for science, medicine and rehabilitation, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand 2 department of physiotherapy, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand corresponding author: b olivier (benita.olivier@wits.co.za) in cricket, the pace bowler aims to outsmart the batsman on strike with a good quality delivery performed at maximum ball release speed, with perfect accuracy, and a good line and length. the bowling action consists of four phases: the run-up phase, the pre-delivery (or gather) phase, the delivery phase, and the follow-through phase, with unique trunk movements contributing to each phase. the pre-delivery phase requires the trunk to hyperextend on back foot landing. as the ball is being delivered, the trunk moves into flexion (lateral flexion) away from the delivery arm, and rotates towards the nondelivery arm. the repetitive execution of the bowling action activates the trunk muscles in the same asymmetrical manner with each delivery, potentially resulting in this particular pattern of muscle hypertrophy.[1, 2] the topic of trunk musculature is frequently raised when sport and performance are discussed. earlier research from hodges and richardson[3] shows that the transversus abdominis activates before the trunk starts moving. this implies that the transversus abdominis acts as a trunk stabiliser when power is produced by the extremities. akuthota and nadler[4] further explain that when the external oblique, internal oblique and transversus abdominis contract, the intraabdominal pressure increases, tensioning the thoraco-lumbar fascia. the thoraco-lumbar fascia connects to the upper and lower limbs posteriorly and by incorporating the abdominal fascia anteriorly and the oblique muscles laterally, a corset is formed around the abdomen, so increasing the intra-abdominal pressure. opposing views exist regarding the role of trunk muscle stability and strength-endurance in athletic performance as investigated in sports other than cricket. an eight-week core endurance programme improved some aspects of core stability in rowers but did not affect their functional performance.[5] similarly, after six weeks of core conditioning training in male runners, core stability improved but running economy remained unchanged.[6] in contrast, core stability training has been shown to improve sports performance measures in other studies [7, 8]. throwing velocity improved after handball players underwent 10 weeks of core training.[7] in a cross-sectional study amongst action cricket fast and fast-medium bowlers, a relationship was found between good core stability and a high ball release speed; however, trunk muscle strength-endurance, thickness and the accuracy of deliveries were not measured.[8] the thickness and symmetry of trunk muscles between dominant and non-dominant sides in injured and uninjured pace bowlers has been investigated by means of ultrasound. in bowlers with no pain, the abdominal wall of the non-dominant side was thicker than that of the dominant side.[1, 2] there was no difference in side-to-side thickness of the transversus abdominis.[2] in another study, the cross-sectional area of the lumbar multifidus was symmetrical in injury-free bowlers, but smaller on the non-dominant side in those who had sustained an injury during the season.[9] different patterns of muscle morphometry exist in adolescent pace bowlers, depending on whether or not they have pain during movement. asymmetry of the trunk muscles and the effect of injury on the trunk muscle morphometry in the prediction of potential injury has been well described.[1, 9] however, compared to other sporting codes, studies investigating the relationship between pace bowling performance and trunk muscle stability, information on strength-endurance, and trunk muscle thickness are lacking in the literature. pace bowlers may contribute greatly to a team’s success when bowling accurately, at the right speed, and taking background: the trunk connects the upper and lower limbs and transfers energy during movement. exploring the role of the trunk muscles in bowling performance affords us the opportunity to uncover potential mechanisms to improve bowling performance. objectives: to investigate the association between bowling performance and trunk muscle stability, strength-endurance and thickness in adolescent pace bowlers. methods: adolescent pace bowlers participated in this crosssectional study. trunk muscle stability was measured using sahrmann’s stability scale, strength-endurance using the bourbon trunk muscle strength test and thickness of the abdominal wall and lumbar multifidus muscles using ultrasound imaging. results: forty-six pace bowlers with a mean age of 15.9 ±1.2 years participated. the average ball release speed was 109.2±11.8 km.h-1. this measurement was higher in level four of stability than in level two (mean difference 22.2 ± sd 6.8 km.h-1; p= .018). no link between ball release speed and strength-endurance could be found. multiple correlations of moderate strength (r > 0.4) exist between ball release speed and absolute trunk muscle thickness with height and weight as confounding factors. the relationship between accuracy and the trunk muscle variables investigated in this study is weak. conclusion: bowlers with better trunk muscle stability bowled faster than those with a lower level of trunk stability, irrespective of their age, height and weight. trunk muscle thickness correlated with ball release speed; however, confounding factors such as height and weight play a role and therefore, findings need to be interpreted with caution. keywords: fast bowling, core muscles, ball release speed, accuracy s afr j sports med 2022;34:1-6. doi: 10.17159/2078-516x/2022/v34i1a12521 mailto:benita.olivier@wits.co.za http://dx.doi.org/10.17159/2078-516x/2022/v34i1a12521 https://orcid.org/0000-0002-8689-9162 https://orcid.org/0000-0001-9287-8301 https://orcid.org/0000-0001-9470-6087 original research sajsm vol. 34 no.1 2022 2 wickets or putting the opposition’s run-rate under pressure. therefore, this study aims to investigate the association between bowling performance, namely ball release speed and bowling accuracy, and trunk muscle stability, trunk muscle strength-endurance and trunk muscle thickness in adolescent pace bowlers. methods study design, study setting and participants this observational cross-sectional study included pace bowlers between the ages of 13 and 18 years from their school’s a-teams. directors of cricket at four secondary schools had their a-team coaches nominate all pace bowlers to be invited to take part in the study. only male participants were included due to the limited number of female players, and to create a homogenous group. participants with previous upper or lower limb surgery or extensive lower back interventions, e.g. spinal facet infiltrations, were excluded from the study. data collection took place in the outdoor cricket nets of the participating schools. this study was adapted from a research report conducted to fulfil requirements for the degree of master in physiotherapy,[10] thus ethical clearance was obtained from the human ethics research committee of the university of the witwatersrand, and both consent and assent was signed by parents and participants respectively. the sample size was calculated using cohen’s default interpretations, using g power 3.1.9.2 and a two-tailed design. the power of 0.8 with a medium to large effect size (0.4) was calculated as 44 participants. the resulting critical t value was 2.02, with a power value of 0.955. protocol the participants were instructed to bowl six match pace deliveries, one ball following the other with approximately one minute in between deliveries, aiming for the top of the wicket on the off-side as if they were bowling to a righthanded batter. each participant was allowed three practice balls to familiarise themselves with the target. ball release speed was measured using a hand-held radar speed gun (stalker, ats, texas). the radar speed gun was positioned approximately five metres behind the point of ball release, as closely in line with the bowler’s upper limb trajectory as possible. the average ball release speed was used in the analysis. bowling accuracy was measured using a black shade cloth target with scoring zones sewn onto it in white and a horizontal line in red, 50 centimetres off the ground. a maximum of 100 points was scored if the ball made contact in the zone of the off-stump, 50 and 25 points in adjacent zones and zero if the target was missed altogether (figure 1).[11] the median accuracy score was used in the analysis. the sahrmann stability scale[12] was used to assess trunk muscle stability. a chattanooga pressure biofeedback (encore medical, australia) was inflated to 40 mm hg and positioned in the lumbar lordosis with the participant in supine crooklying [13]. the participant was instructed to maintain the “drawin manoeuvre” throughout a level, not allowing the spine to move, which would result in a pressure deviation of more than 10 mm hg on the pressure biofeedback – an indication of spinal stability lost. the score achieved was the level successfully passed on a scale of one-five, where after the legs were added acting as levers to increase the level of difficulty (figure 2). the bourbon trunk muscle strength test (tms) [14] was used to assess trunk muscle strength-endurance. time was measured in seconds at the point of failure for the particular muscle chain. the ventral, lateral left and right, and dorsal trunk muscle chain tests were performed in randomised order with a 10 minute recovery time allowed between tests. muscle thickness of the transversus abdominis, external oblique and internal oblique was measured at rest, and during fig. 1. bowling accuracy target fig. 2. sahrmann stability scale: a) level 1; b) level 2; c) level 3; d) level 4; e) level 5 original research 3 sajsm vol. 34 no.1 2022 the abdominal drawing-in manoeuvre. the lumbar multifidus muscle at the l4, 5 facet joint was measured at rest using ultrasound imaging. measurements were recorded in millimetres with on-screen callipers from the middle of the one fascia layer to the middle of the next layer using a dp6600 digital ultrasonic imaging system® (shenzhen mindray bio-medical electronics co., ltd, china) with a 5mhz curvilinear transducer and a large footprint (≥60mm). data reduction the following calculations were done:  percentage change (a percentage of muscle thickness at rest) = (muscle activated muscle at rest) ÷ muscle at rest × 100[2]  contraction ratio (the ratio of the contracted muscle thickness to the muscle thickness at rest) = muscle thickness contracted/muscle thickness at rest[15]  ta preferential activation ratio (difference in the ta proportion of the total lateral abdominal muscle thickness in going from the relaxed to the contracted state) = (ta contracted/ta + io + eo contracted) – (ta at rest/ta + io + eo at rest)[15]  relative thickness (a percentage of the total thickness of all three muscles together) = eorest / (eorest + iorest + tarest) x100[15]  relative thickness (a percentage of the total thickness of all three muscles together) = eocont / (eocont + iocont + tacont) [15]  percentage difference (between sides) = [(largest/smallest value x 100) 100][9, 16] where eo is external oblique; io is internal oblique; ta is transversus abdominis statistical analysis data were analysed using ibm spss statistics for windows (version 26.0. armonk, new york, usa). a pearson’s correlation was conducted for all parametric data, and a spearman’s rank order correlation was conducted for ordinal or non-parametric data. a value of 1 or -1 for the pearson’s (r) and spearman’s (ρ) correlation was considered to be a perfect association, positive and negative values above 0.70 were considered to be strong correlations, those between 0.40 and 0.70 were moderate correlations, and those below 0.40 were weak correlations. multivariate analyses could not be performed due to the size of the dataset as well as a high level of multicollinearity among the independent variables. a oneway analysis of variance (anova) followed by a tukey post hoc test were conducted to determine whether there is a difference of means in average ball release speed among five levels of stability. spearman’s rank order correlation was conducted to determine the relationship between accuracy and ball release speed, trunk muscle stability, muscle strengthendurance, and muscle thickness. a pearson’s correlation was conducted to assess the relationship between average ball release speed and muscle strength-endurance, as well as muscle thickness. the association between age and height, and weight with absolute trunk muscle thickness was determined using both the pearson’s and spearman’s rank order correlation as appropriate for the distribution of the data. ordinal logistic regression was used to explore the association between age, height and weight on the likelihood of a higher level of stability using the wald test for parameter and model fit. results forty-six pace bowlers with a mean age of 15.9 years (standard deviation (sd)=1.2; median= 16.0; range=14-18 years), a mean height of 173.9 cm (sd=8.0; median=174.0; range=157.0-193.0 cm) and mean weight of 65.0 kg (sd=16.8; median=62.5; range=43.0-140.0 kg) participated. forty-two (91%) were right-handed and four (9%) were left-handed bowlers. ball release speed and accuracy the participants bowled at a mean of 109.2 km.h-1 (sd=11.8; median=105.0; range=85.5-128.9 km.h-1) and a median accuracy score of 70 percent (range=56-87 %) was attained. there was no association between ball release speed and accuracy (ρ= -.08; p= .586). ball release speed, bowling accuracy, age, height and weight ball release speed was moderately associated with age (r= .43, p= .003) and height (r= .49, p= .001), and weakly associated with weight (r= .39, p= .007). however, there was no association between bowling accuracy and age (ρ= .04, p= .770), height (ρ = .06, p= .686) or weight (ρ= .09, p= .551). ball release speed, accuracy and trunk muscle stability the median value for trunk muscle stability was three (range=one-five) on the sahrmann stability scale. there was a difference between levels of performance on the sahrmann stability scale as determined by one-way anova (f(4,41)= 3.473; p= .011) (table 1). a tukey post hoc test table 1. the association between ball release speed and trunk muscle stability (n=46) descriptive one-way anova results trunk muscle stability ball release speed (km.h-1) sum of square mean square degree of freedom f-statistic p-value level 1 106.4 (10.2) between groups 1607.6 401.9 4 3.473 .011 level 2 99.7 (10.4) level 3 105.5 (10.3) level 4 121.9 (6.1) within groups 4402.7 107.4 41 level 5 118.22 (13.98) data expressed as mean (sd) unless indicated otherwise. original research sajsm vol. 34 no.1 2022 4 revealed that the average ball release speed was higher in level four of stability than in level two (mean difference 22.2 ± 9.6 km.h-1; p= .018). there were no differences in ball release speed among the other levels of stability. there was no relationship between bowling accuracy and trunk stability (ρ= -.011; p= .940). ordinal logistic regression was performed to determine the effect of age, height and weight on the likelihood of a higher level of stability. the model explained 4.6% (nagelkerke r2) of the variance in levels of stability. the logistic model was not a good fit (χ2(3)= 2.025; p= .567) and none of the predictor variables in the ordinal regression analysis were found to contribute to the model [age: wald= 1.014, p= .314; height: wald= .056, p= .495; weight: wald= .897, p= .344]. ball release speed, accuracy and trunk muscle strengthendurance trunk muscle strength-endurance is shown in table 2. there was no relationship between either ball release speed or accuracy, and strength-endurance. ball release speed, accuracy and trunk muscle thickness multiple correlations of moderate strength (>0.4) exist between ball release speed and absolute trunk muscle thickness as measured at rest and in a contracted state (table 3). to determine the role of age, height and weight in absolute trunk muscle thickness, correlations between these variables were determined and can be found in the online supplementary material tables 1, 2 and 3. moderate correlations exist between age and two of the absolute trunk muscle thickness-related variables, with 16 weak correlations, while between height and absolute trunk muscle thickness, 13 of the 18 variables showed moderate correlations. three strong, 13 moderate and two weak correlations were found between weight and absolute trunk muscle thickness. no relationship seemed to exist between ball release speed and trunk muscle thickness-related calculations, such as percentage change, contraction ratio, relative thickness at rest or relative thickness when contracted (table 4). the highest correlation was that of the contraction ratio between the thickness of the non-dominant internal and external oblique when contracted and the same muscles when at rest. however, this correlation can be interpreted as weak (r=.25; p= .028). some weak correlations were determined between bowling accuracy and absolute muscle thickness (online supplementary material – table 4), as well as between bowling accuracy and the derivatives of muscle thickness (online supplementary material – table 5). the highest of these was a correlation between the relative thickness of the dominant transversus abdominis, which is expressed as a percentage of total thickness of all three muscles together, and bowling accuracy ( r= .40; p= .006). discussion the findings from this research study, a first of its kind, answered a valuable research question in our quest to uncover the exact mechanisms behind bowling performance. the findings from this paper form a basis for future research, where mechanisms related to trunk muscle stability, strengthendurance and thickness, can be explored further. in this study, adolescent pace bowlers with better trunk table 2. the association between strength-endurance and accuracy and average ball release speed (n=46) strength-endurance (seconds) accuracy ball release speed trunk muscle chain mean (sd) median (range) ρ p-value r ρ p-value dorsal 69.54 (23.10) 67.50 (25 – 130) -.248 .096 .209 .164 ventral 70.09 (27.91) 63.50 (23 – 131) -.247 .098 .153 .155 non-dominant lateral 48.07 (16.83) 45 (23 – 131) -.034 .821 .013 .930 dominant lateral 49.46 (16.20) 47.50 (16 – 89) .125 .407 -.070 .322 r, pearson’s correlation performed for parametric data; ρ, spearman’s rank order correlation performed for non-parametric data. table 3. the relationship between ball release speed and absolute trunk muscle thickness at rest and when contracted (n=46) at rest contracted trunk muscle r ρ p-value r ρ p-value non-dominant eo .02 .882 .22 .142 dominant eo .08 .602 .10 .519 non-dominant io .33 .025 .45 .002 dominant io .25 .091 .34 .020 non-dominant ta .53 <.001 .42 .004 dominant ta .54 <.001 .46 .001 non-dominant abd .33 .026 .54 <.001 dominant abd .32 .030 .40 .006 non-dominant multifidi .4 .006 dominant multifidi .20 .186 r, pearson’s correlation performed for parametric data; ρ, spearman’s rank order correlation performed for non-parametric data; eo, external oblique; io, internal oblique; ta, transversus abdominis; abd, abdominal wall (eo+io+ta). original research 5 sajsm vol. 34 no.1 2022 muscle stability bowled faster than those with a lower level of trunk stability, irrespective of their age, height and weight. hilligan[8] reported a good relationship between ball release speed and trunk muscle stability in adult (18-35 years old) male indoor pace bowlers, although the participants in his study were older and performed slightly different stability tests. portus et al.[11] could not correlate trunk muscle stability to bowling performance (ball release speed and accuracy), but they found that the bowlers who scored higher on the trunk muscle stability test were also bowling with a slightly more bent knee at front foot impact. therefore, bowlers landing on a bent knee are believed to have possibly adapted and improved their trunk muscle stability, enabling them to use the trunk as a rigid lever to generate ball release speed, instead of an extended knee. an extended knee angle has been associated with an increase in ball release speed, whereas a slightly flexed knee is recommended to prevent injury due to a reduction in load placed on the lumbar spine – a trade-off that is difficult to negotiate for any bowler. therefore, it seems like bowling with a slightly flexed knee will reduce lumbar loads and increase trunk muscle stability, which will allow a bowler to bowl faster, despite bowling with a flexed knee. however, the exact mechanism is unclear, and causality cannot be assumed. there was no relationship between ball release speed and trunk muscle strength-endurance, highlighting the potential differences in constructs tested using the bourbon tms, namely the amount of time a player can hold a certain position vs the functional demands of the pace bowling action. also, none of the variables influenced players’ accuracy scores, which leaves us with the impression that accuracy is not dependent on trunk muscle stability, strength-endurance or thickness, but that other mechanisms are at play. there seems to be an overall moderate correlation between ball release speed and absolute trunk muscle thickness, which means those who bowl faster have thicker trunk muscles. although it is very tempting to recommend that trunk muscle thickness be increased to increase ball release speed, when analysing the role of age, height and weight, confounding relationships became apparent. there seems to be a pertinent relationship between weight and absolute muscle thickness, where the heavier bowlers had thicker muscles. however, there is a weak correlation between ball release speed and weight, which means those who bowled faster were not necessarily heavier. age and height were moderately correlated with ball release speed, although only height showed a moderate relationship with absolute trunk muscle thickness. this points us to the complexity and the importance of considering confounding factors in our methodological planning and statistical analysis. in this study, no regression analysis could be done due to multi-collinearity between variables. considering these findings, results should be interpreted with caution, and findings may indicate pure associations while a cause-effect relationship should not be assumed. future studies should include larger sample sizes which will allow for subgroup analysis and thus confounding variables can be eliminated. the inclusion of female pace bowlers, as well as an table 4. the relationship between ball release speed and derivatives of absolute trunk muscle thickness (n=46) r ρ p-value percentage difference eo at rest .14 .176 io at rest .23 .062 ta at rest .08 .303 abd at rest .11 .224 eo contracted .02 .458 io contracted .11 .225 ta contracted .05 .365 abd contracted .04 .404 multifidi at rest .10 .252 percentage change non-dominant eo .24 .055 dominant eo .01 .952 non-dominant io .19 .106 dominant io .17 .124 dominant ta -.09 .561 non-dominant ta -.08 .618 contraction ratio non-dominant eo .24 .055 dominant eo .01 .952 non-dominant io .19 .106 dominant io .17 .124 non-dominant ta -.08 .618 dominant ta -.09 .561 non-dominant eoio .25 .028 dominant eoio .16 .146 relative thickness at rest non-dominant eo -.28 .058 non-dominant io .18 .225 non-dominant ta .19 .215 dominant eo -.23 .122 dominant io .01 .967 dominant ta .40 .006 relative thickness contracted non-dominant eo -.06 .339 non-dominant io .13 .187 non-dominant ta -.14 .370 dominant eo -.20 .094 dominant io .05 .377 dominant ta .12 .412 r, pearson’s correlation performed for parametric data; ρ, spearman’s rank order correlation performed for non-parametric data; eo, external oblique; io, internal oblique; ta, transversus abdominis; abd, abdominal wall (eo+io+ta). original research sajsm vol. 34 no.1 2022 6 exploration of the role of the lumbo-pelvic-femoral complex and growth spurts on bowling performance in future research projects is strongly advised. longitudinal studies are recommended to explore causality, something that was not possible in this study considering its cross-sectional nature. in addition, future intervention studies can explore the effectiveness of a trunk muscle strengthening programme on ball release speed while considering age, height and weight as confounders. it is possible that the shorter, lighter bowlers could possibly benefit from specific trunk muscle pattern strengthening to improve ball release speed, because a muscle should become thicker once it is strengthened. against the results of the current study, this could then benefit the bowler in terms of ball release speed. however, the findings from this study cannot support such a recommendation in clinical practice. conclusion adolescent pace bowlers with better trunk muscle stability bowled faster than those with a lower level of trunk stability, irrespective of their age, height and weight. trunk muscle thickness correlated with ball release speed, however, confounding factors such as height and weight play a role and therefore this study’s findings need to be interpreted with caution and future research is required. bowling accuracy was not linked to trunk muscle stability, strength-endurance or thickness, and other mechanisms are clearly at play. conflict of interest and source of funding: the authors declare no conflict of interest. the authors would like to thank the faculty research committee of the associated tertiary institution as well as the national research foundation for financial support. acknowledgements: thank you to the headmasters, directors of cricket, parents and participants for participating in this study. author contributions: bo contributed to conceptualisation, formal analysis and interpretation of data; writing, review and editing. f-m o contributed to conceptualisation, design, methodology, writing original draft and approval of the version to be published. nm contributed to formal analysis and interpretation of data and 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[doi: 10.1002/mus.20589][pmid: 16775833] https://hdl.handle.net/10539/25272 118 sajsm vol. 27 no. 4 2015 commentary calories and steps! how many days of walking/hiking in the himalayas does one christmas lunch translate to? j d pillay,1 phd; w brown,2 phd 1 department of basic medical sciences, faculty of health sciences, durban university of technology, south africa, 4001 2 centre for research on exercise, physical activity and health, school of human movement and nutrition studies, university of queensland, st lucia, australia corresponding author: j d pillay (pillayjd@dut.ac.za) background. the festive season is a time when people are at risk of overeating and weight gain. an active break during this time can help maintain energy balance. objectives. to determine steps taken during a walk/hike to everest base camp and back and compare estimated activityrelated energy expenditure to a typical christmas lunch. methods. five adults (39-70 years) completed an 11-day walk/hike. pedometer-measured steps were recorded at two cadences: ‘aerobic’ (>100 steps/minute for 10 consecutive minutes) or ‘slower’ steps. activity-related energy expenditure was estimated using generic values for walking uphill/downhill at each cadence. energy intake of a typical christmas lunch was estimated. results. participants accumulated a total of 143 770 steps, or 13 070 (sd 8 272) steps/day, 20% of which were ‘aerobic’. total walk-related energy expenditure was estimated at 22 816  kcals, or 1 901 (sd 580) kcals/day. conclusion. estimated energy intake in one christmas lunch equates to 1.7 days of walking/hiking. keywords. energy intake, physical activity, energy expenditure, pedometer s afr j sports med 2015;27(4):118-120. doi:10.17159/2078-516x/2015/ v27i4a158 christmas is a time when most people eat far too much food than usual, certainly more than is required to balance energy expenditure. an article in the daily mail[1] advised readers to ‘think before you reach for that extra mince pie’ and claimed that the food and drink consumed during christmas lunch/dinner festivities could provide an energy intake equating with 7 000 kilocalories. one of the authors (jdp) joined four friends over christmas in a walk/hike to everest base camp (ebc) and back (starting from, and ending at, the most frequently used access to the himalayas, lukla international airport). in this paper the estimated energy expenditure is compared during the 11-day hike, based on pedometer steps, and compared to energy intake based on a diet record kept by the second author who stayed at home to eat christmas lunch. methods study design an observational and descriptive case study. participants and setting five adults (three men, two women, aged 39-70 years) walked to ebc and back over 11 days in december 2014. data collection all trek participants wore a pedometer (omron hj720itc) on their hip from the start to the end of each daily walk, and daily step counts at two cadences were recorded: ‘aerobic’ steps were those accumulated at a cadence of >100  steps/minute in bouts of at least 10 minutes; ‘slower’ steps were accumulated at a lower cadence and/or in shorter bouts. the validity and reliability of this brand and model of pedometers have been shown to be acceptable under prescribed and self-paced walking conditions in both healthy and overweight adults.[2] total distances and hours of walking time were estimated from diaries and from information provided by the himalayan national parks authority.[3] christmas lunch energy intake was estimated from the second author’s food records and the tables available in the “myfitnesspal” iphone and android application.[4] data management and statistical analyses general characteristics of the study group and number of total steps, ‘aerobic’ steps and ‘slower’ steps each day, and estimated walk-related energy expenditure were summarised using descriptive statistics (spss, version 23.0). walk-related energy expenditure was calculated by multiplying time (hours) spent in ‘slower’ steps by 5 mets (ascending) or 4 mets (descending), and time spent in ‘aerobic’ steps by 7 mets (ascending) and 6 mets (descending), hence allowing for the greater amount of energy needed to walk uphill. resulting met.hours values for ‘aerobic’ and ‘slower’ steps were summed, and multiplied by average body weight to derive kcals/day of energy expenditure. summary data are reported as means and standard deviations. results participant characteristics participants were three men and two women, average age 54.8 (sd 11.1) years, average weight 66.1 (sd 8.4) kg and average body mass index 24.0 (sd 1.8) kg/m2. average daily and total steps  step data and estimated walk-related energy expenditure values are shown in table 1. the average total steps recorded during the hike to ebc and back was 143 770 or an average of 13 070 (sd 8 272) steps/ day. the inter-individual variability, expressed as the co-efficient of variance in mean steps/day was 63% (sd/mean steps * 100). approximately one-fifth of these steps were at the ‘aerobic’ cadence. step counts on ‘ascent days’ (days 1, 2, 4, 5, 7 and 8) ranged from 6 265 to 12 748 steps/day, with fewer steps on days 3 and 6, which were ‘acclimatisation’ days, involving shorter hikes. step counts on ‘descent days’ (days 9, 10 and 11) were much higher, in keeping with the easier downhill walking. estimates of energy expenditure and energy intake energy expenditure in ‘aerobic’ steps (61.53 met.hours in total) accounted for about one fifth of total energy expenditure. overall, total walk-related energy expenditure was 21 093 kcals, or 1 918 kcals/day. mailto:pillayjd@dut.ac.za http://dx.doi.org/10.17159/2078-516x/2015/v27i4a158 http://dx.doi.org/10.17159/2078-516x/2015/v27i4a158 sajsm vol. 27 no. 4 2015 119 table 1. daily steps, walking time and estimated energy expenditure (n=5; 3 men, 2 women, aged 39‑70 years) day of hike total steps/day ‘normal’ steps/day ‘aerobic’ steps/day total walk time (hours/day) ‘normal’ walk time (hours/day) met.hours for ‘normal’ walkinga ‘aerobic’ walking time (hours/day) met.hours for ‘aerobic’ walkingb energy expenditure (kcal/day)c day 1 10 713 9 257 1 456 3.75 3.38 16.88 0.38 2.63 1 287 day 2 10 902 10 902 0 7.00 7.00 35.00 0.00 0.00 2 310 day 3 4 276 4 087 189 3.00 3.00 15.00 0.00 0.00 990 day 4 11 023 10 855 168 6.00 6.00 30.00 0.00 0.00 1 980 day 5 12 748 10 400 2 348 6.00 4.80 24.00 1.20 8.40 2 138 day 6 1 917 1 453 464 2.50 2.00 10.00 0.50 3.50 891 day 7 6 265 6 265 0 6.00 6.00 30.00 0.00 0.00 1 980 day 8 9 230 8 430 800 8.00 7.20 36.00 0.80 5.60 2 746 day 9 25 746 15 477 10 270 7.00 4.80 19.20 3.20 19.20 2 534 day 10 23 609 15 393 8 215 7.00 4.90 19.60 2.10 12.60 2 125 day 11 27 341 19 173 8 167 8.00 5.60 22.40 1.60 9.60 2 112 total 143 770 111 692 32 077 65.25 54.68 258.08 9.78 61.53 21 093 average 13 070 10 154 2 916 5.9 5.0 23.10 0.90 5.70 1 901 standard deviation 8 272 4 951 3 750 1.91 1.57 8.12 1.00 6.02 580 a mets for slow walking = 5 on ascent and 4 on descent b mets for aerobic walking = 7 on ascent and 6 on descent c estimated as total walk-related met.hours * average body weight (66 kg) table 2. estimated energy of a christmas lunch using myfitnesspal app item approximate serving size approximate kcals sparkling champagne 2 x 150 ml 215 red wine (shiraz) 2 x 175 ml 240 vegetable soup 200 ml 160 roast turkey 120 g 150 roast pork 100 g 260 crackling 20 g 130 sausages 2 130 roast potato 100 g 160 roast parsnip 65 g 125 brussels sprouts 100 g 60 broccoli 100 g 35 green beans 100 g 31 gravy 3 tablespoon 40 bread sauce 50 g 50 stuffing ¼ cup 75 cranberry sauce 2 tablespoon 55 christmas pudding 1 slice 300 brandy butter 25 g 120 custard ½ cup 160 mince pie 1 109 cheese – stilton 30 g 125 cheese – camembert 30 g 95 biscuits 6 small 120 baileys 50 ml 165 chocolate balls 2 150 cherries ½ cup 35 total 3 295 estimated met.hours/day for ‘aerobic’ and ‘normal’ walking are also shown in table 1. the energy value of food and drink consumed in a typical christmas lunch is shown in table 2. the overall energy intake in this single meal was 3 295 kcals, which equates with about 1.7 days of walking/hiking in the himalayas (see table 1 and table 2). discussion during an 11-day hike to ebc, five people each accumulated about 13 000 steps/day, which equates to an estimated walk-related energy expenditure of about 1 900 kcals/day. during this time one person sat at home and consumed 3 295 kcals in one christmas lunch. over-consumption of food and drink during the festive season is common and is not restricted to a single day, as it is not uncommon to have several christmas meals with different friends/family groups during this period. the data presented here illustrate how one group addressed the energy imbalance of christmas, while participating in an exciting expedition to the himalayas. in doing this, it was estimated that one christmas lunch was the equivalent of 1.7 days of walking/hiking at an average 13 070 steps/day. current public health messages support the accumulation of at least 10 000 steps/day, and using these caloric and step/day estimates, 2.2 days of accumulating 10 000 steps might be adequate to work off that christmas lunch. these estimates were, however, based on at least one-fifth of these steps being accumulated at a moderate-fast pace. to the authors’ knowledge this is the first study to record pedometer steps during an 11-day hike with the data being translated to estimates of energy expenditure. a pedometer was used to allow the estimation of steps that accords with the notion of ‘aerobic’ activity in bouts of at least ten minutes, which is the level of activity recommended in many national physical activity guidelines.[5] a limitation of the method in this study was that generic met values were used to account for intensity. under conditions of extreme (subzero) temperatures and altitude, even very slow movement involves significant exertion, so these met values (ranging from 4 to 7) were 120 sajsm vol. 27 no. 4 2015 chosen to reflect the authors’ perceptions of the effort involved in walking up and downhill in these conditions. in comparison, three mets is indicative of walking at a moderate intensity on flat ground.[6] conclusion this case study provides information on steps/day during an 11-day hike along a popular mountain range. it also highlights the potential imbalance of energy intake and expenditure over the festive season. the authors are not proposing that everyone should go to the himalayas to walk off their christmas lunch, but a daily walk with an energy expenditure equivalent to around 1 900 kcals, as shown here for this 11-day walk, will offset 60% of the energy consumed in a typical christmas meal. authorship. all authors consent to publication. competing interests. the authors declare that they have no competing interests. the manuscript has not been previously published and is not presently under consideration by another journal, and will not be submitted to another journal before the final editorial decision is rendered. contributorship. jdp was responsible for the acquisition of pedometer data and wb estimated the energy content of christmas lunch. both authors contributed to analysis and interpretation of the data and to the writing of the manuscript. acknowledgements. the authors wish to use this opportunity to pay tribute to those recently affected by the natural disasters in nepal. they also thank the trek participants for collecting the pedometer data during their holiday. references 1. the daily mail. think before you reach for that extra mince pie! published by caroline mcguire for mailonline. 16 december 2014. [http://www.dailymail.co.uk/ femail/food/article-2874990/femail-lists-7-000-calories-average-christmas-daydinner.html] 2. holbrook ea, barreira tv, kang m. validity and reliability of omron pedometers for prescribed and self-paced walking. med sci sports exerc 2009;41(3):670-674. [https://dx.doi.org/10.1249/mss.0b013e3181886095] 3. great himalayan national park. [http://greathimalayannationalpark.com] accessed september 7, 2015. 4. connected fitness (2013). myfitnesspal (version 6.6.1)[mobile application software]. [http://www.myfitnesspal.com] 5. world health organisation. global recommendations on physical activity for health. geneva: world health organisation; 2010. 6. blair sn. how to assess exercise habits and physical fitness. in: ne miller, jd matarazzo, sw weiss, ja herd, eds. behavioral health: a handbook of health enhancement and disease prevention. new york: wiley; 1984. http://www.dailymail.co.uk/femail/food/article-2874990/femail-lists-7-000-calories-average-christmas-day-dinner.html http://www.dailymail.co.uk/femail/food/article-2874990/femail-lists-7-000-calories-average-christmas-day-dinner.html http://www.dailymail.co.uk/femail/food/article-2874990/femail-lists-7-000-calories-average-christmas-day-dinner.html https://dx.doi.org/10.1249/mss.0b013e3181886095 http://greathimalayannationalpark.com http://www.myfitnesspal.com rectal temp sajsm ver 5 sajsm vol 17 no. 1 2005 29 introduction the technology necessary to log data remotely and independently has been available for some years. this technology has been applied mostly to environmental and natural sciences, however, and not in life sciences. this was due primarily to the cost of the technology and the small demand for it in the life sciences, especially in studies of exercise physiology. our recent collaboration with a local technology company (sygade solutions (pty) ltd., johannesburg) has resulted in the use of miniature data loggers to record rectal temperature, heart rate (hr), and altitude during road and cycle racing. this technology has the potential to measure these variables simultaneously and in a free-living situation and will therefore contribute to more innovative research. description of the data logger the data loggers were tested in the laboratory from 35 44¡c, and returned an accuracy ranging from 0.22% to 0.1%. each logger weighs 79 g and has dimensions of 105 x 58 x 20 mm (length x width x height, respectively). the loggers use a 16-bit micro-processor operating at 13 mhz, and draw 20 milliamps during operation. each is powered by a single aaa/1.5 v battery that can supply enough current for up to 12 hours of logging. data are stored on a flash device similar to those used currently in digital cameras. this allows for the retention of data even if power is removed during use. the loggers can record up to 12 hours of data at 2-second intervals in the absence of hr. when hr is recorded in addition to rectal temperature, the logging time decreases in direct proportion to the time interval between heart beats so that maximum logging time is shortened to 7 hours if a hr of 220 beats/minute is maintained. the minimum hr that can be logged is 30 beats/minute. the loggers measure hr in milliseconds from beat to beat. because the hr transmitters are not suited to beat-to-beat calculations, and to reduce interference from other hr monitors, the hr transmitters were hard-wired to the data logger for maximal accuracy. temperature is measured by supplying the probe with a very accurate reference voltage/current and then measuring the changes with a 20 bit analog to digital converter. this is then converted to temperature by means of a calibration table, as supplied by the temperature probe manufacturer (vha plus, irving, texas, usa). the air pressure sensor is a motorola mpx4115 which is sensitive to pressure changes within 1 m of vertical distance. however, for the air pressure sensor to measure altitude accurately in metres above sea level, a sophisticated and accurate calibration is required. therefore, the loggers were designed not to give accurate meter readings, but instead to give only relative changes in pressure, thus creating a profile of the race course. this allows the user to place an athlete at specific points on a course where changes in altitude are known and frequent. the software for the micro-processor was compiled initially on a pc and then loaded via a special wire interface to the processor. data are retrieved by interfacing the logger with a pc via a download cable inserted into the hr transmitter input. the programmer is then able to issue special control commands to the logger via the pc. the data are stored in a raw binary format. the processing and separating of data took place on the pc to produce text files that were then delimited in a microsoft excel workbook and plotted using the graphpad prism software package (graphpad software inc., san diego, california, usa). the loggers contain a function that allows the user to log an event during the data-logging period. the user can log an event by pushing a button on the logger at a point specified by the researcher, for example before, during, or after the race. this allows the researcher to know exactly where the start and finish of the course are, for example, after the data have been downloaded and reduced. short report new use of current technology to measure rectal temperature and heart rate during endurance exercise j p dugas (bsc (med) (hons))1 b burger (bsc (eng))2 t d noakes (mb chb, phd, md)1 1 mrc/uct research unit for exercise science and sports medicine, sports science institute of south africa, university of cape town 2 sygade solutions, (pty) ltd, johannesburg correspondence: j p dugas po box 115 newlands 7725 tel: 021 650 4572 fax: 021 686 7530 e-mail: jdugas@sports.uct.ac.za rectal temp sajsm ver 5 5/4/05 12:10 pm page 29 pilot work data were logged approximately every 0.03 minutes for the duration of a 100 km cycle race (fig. 1) and a 21.1 km running race (fig. 2). at the start and finish of each race the athlete logged an event to distinguish the starting and finishing points. the event is marked by a spike in the data set that allows the researcher to identify the event and then remove the spike from the data for presentation purposes. the cycling course profile was then compared with a profile provided by the race organisers to determine specific points on the course during the data session, and these points were then noted on the logger s profile (fig. 1). the running course had fewer geographical landmarks than the cycling course. altitude readings from each kilometre on the running course were obtained from the organisers and used to generate a profile of the race course (fig. 2c). this profile was then compared with the profile created by the logger (fig. 2b). discussion the advent of this technology has already yielded a novel finding. the ability to measure the rectal temperature with such high resolution and over relatively long periods of time has allowed us to show that during endurance exercise rectal temperature is a dynamic variable and appears to change with metabolic rate and course terrain, the former normally being a function of the latter. in addition, because data of this type have never before been collected, we can see that although the rectal temperature is dynamic in nature as opposed to static, it remains within a range of approximately 2¡c. this sheds new light on thermoregulatory studies, and opens new avenues of research in this area that were previously not available. 30 sajsm vol 17 no. 1 2005 fig. 1. data from a 100 km cycle race. the course profile was measured using an uncalibrated air pressure sensor so that it recorded only relative changes in altitude. the heart rate transmitter was wired directly to the logger for accuracy. data were logged approximately every 0.03 minutes to produce approximately 60 000 data points. fig. 2. data from a 21.1 km running race. rectal temperature (2a) and air pressure (2b) were recorded continuously during the run. altitude at each kilometre (2c) was obtained from the race organisers for comarison with the course profile generated from the logger. a b c rectal temp sajsm ver 5 5/4/05 12:10 pm page 30 sportsmed_june04 sports medicine vol 16 no.2 2004 17 introduction in response to a wide range of homeostatic disturbances, such as trauma, neoplasms, bacterial infection, burn injury and immunologically mediated inflammatory states,7,10 the body initiates an acute phase response (apr). the apr is synonymous with alterations in circulating acute phase proteins (app), the production of which is mainly due to de novo synthesis.20 this complex series of reactions serves to activate repair processes and prevents ongoing tissue damage by altering metabolic, endocrinological, neurological and immunological functions.6 strenuous exercise has been shown to elicit an increase in app.3,11,21,30 documentation of the acute phase reactants response to physical activity is important when interpreting metabolic/biochemical adaptations and/or maladaptations that occur with exercise.11 in addition, it provides crucial information with regard to inflammation, healing and adaptation to training stimuli. whilst numerous studies have shown the app c-reactive protein (crp) to be significantly elevated following exercise,18,21,26,27 there still remain a large number of acute phase reactants that have not been thoroughly investigated. original research article alterations in acute-phase reactants (crp, rheumatoid factor, complement, factor b, and immune complexes) following an ultramarathon s j semple (mtech)1 l l smith (phd)1 a j mckune (mmedsci)1 n neveling (ba hons)1 a wadee (phd)2 1department of sport and physical rehabilitation sciences, tshwane university of technology, pretoria 2department of immunology, university of the witwatersrand johannesburg correspondence: s j semple private bag x680 pretoria 0001 tel: 012-318 4324 fax: 012-318 5801 e-mail: semplesj@tut.ac.za abstract objectives. the human body initiates an acute phase response (apr) in response to a wide range of homeostatic disturbances. this complex series of reactions serves to activate repair processes and prevent ongoing tissue damage. an important aspect of the apr is the de novo synthesis of acute phase proteins (app), many of which have not been thoroughly investigated. main outcome measures. alterations in crp (c-reactive protein), c1est, c3, c4, c6, rheumatoid factor (rf) and factor b were determined before and after an ultramarathon. data were analysed using a one-way analysis of variance comparing values to pre-exercise levels. significance was set at p < 0.05. design. venepunctures were performed on athletes participating in an ultramarathon (90 km) 24 hours before, immediately post-exercise (ipe), and 3h, 24h and 72h after the race. serum was stored at –80°c until analysed. crp levels in serum were assessed using the n latex crp kit. the levels of circulating immune complexes (cic) were determined using particle-enhanced nephelometry. complement proteins c1est, c3, c4 and rf were measured using laser nephelometry. c6 and factor b were determined by radial immunodiffusion. results. crp was significantly elevated ipe (58%), 3h post (77%), 24h post (87%) and 72h post (69%). pre-race crp levels were above the normative range (5.10 ± 3.08 mg/l), c6 was significantly elevated (p < 0.05) at 24h post (7.8%) and 72h post (8.8%) exercise. factor b was significantly elevated (p < 0.05) at 72h post exercise (12.8%). rf was significantly elevated at 72h post exercise (6.7%). conclusion. significant increases in selected acutephase reactants occur several days after the exercise event. in addition, as indicated by elevated resting levels of crp, the athletes began the race with some degree of inflammation, presumably as a result of the cumulative training and racing mileage in preparation for the ultramarathon. 18 sports medicine vol 16 no.2 2004 therefore, the aims of this study were firstly to confirm the reported increases in crp following a prolonged, strenuous bout of exercise, and secondly to monitor alterations in less researched acute phase reactants, up to 3 days after an ultramarathon. methods subjects the study was approved by the institutional ethics committee and all subjects provided written, informed consent. six male and 5 female experienced ultramarathon athletes volunteered for the study. the subjects descriptive characteristics were (mean (± sd)): age 43 ± 9 years, height 170 ± 10 cm, weight 64 ± 13 kg, body fat 14 ± 2.9%, maximal oxygen intake (vo2max) 57.5 ± 5.5 ml/kg/min, mileage from january to june 1 450 ± 445 km, and number of completed ultramarathons (90 km) 4 ± 1. blood samples venous blood was drawn from the subjects 24h before their predicted finishing time, immediately post exercise (ipe), 3h post exercise and then at 24h and 72h after an ultramarathon (90 km). concentrations were corrected for changes in plasma volume ipe, but not for the remaining time measurements. corrections for changes in plasma volume were calculated using haematocrit and haemoglobin values in accordance with the methods of dill and costill.5 samples were allowed to stand for 15 minutes, after which the serum was centrifuged at 1 000 g for 10 minutes. samples were stored at –80ºc until analysed. all samples were analysed in duplicate. crp and rheumatoid factor levels of crp and rheumatoid factor (rf) in serum were determined using the n latex crp kit (behring diagnostics, germany). specimens were mixed with polystyrene particles coated with monoclonal antibodies and the intensity of light scatter measured in a behring nephelometer (behring diagnostics, germany) against standards of known concentration. circulating immune complexes the levels of circulating immune complexes (cic) levels were determined using particle-enhanced nephelometry. the assay utilised polystyrene particles coated with human c1q which was added to the subjects’ sera. light scatter due to agglutination of the c1q-coated particles in the presence of cic was measured in a behring nephelometer (behring diagnostics, germany) whereby the concentration of cic was determined in relation to the amount of agglutination detected. c1est, c3 and c4 determination of complement proteins c1est, c3 and c4 in serum was performed using specific anti-sera to c1est, c3c and c4. the immune complexes formed were measured in a behring nephelometer (behring diagnostics, germany) and the amount of c1est, c3 and c4 was calculated by comparison with standards of known concentration. c6 and factor b c6 and factor b were determined by radial immunodiffusion (the binding site, uk). the assays were performed by adding serum and controls of known c6 and factor b concentrations to radial immunodiffusion plates containing nonspecific antibody in an agarose gel. the diameter of immunoprecipitating antigen-antibody complexes radiating out of the wells was measured and compared against a calibrated curve drawn from a range of samples of known concentration. statistical analysis data were analysed using a one-way analysis of variance (anova), contrasting variables to baseline values. significance was set at p ≤ 0.05. where appropriate post hoc tests (tukey) were computed. sas statistical software package was used to compute results. results crp was significantly elevated (p = 0.003) by 58% immediately after the race and was significantly increased (p = 0.001) by 77% 3h after the race. crp remained significantly elevated (p = 0.011) and peaked at 24h post marathon (87%). at 72h post marathon, crp was still significantly elevated (p = 0.0002), but began returning to baseline (69%) (fig. 1). the 24h pre-race sample of 5.10 (± 3.08 mg/l) was elevated above normative ranges for the laboratory in which the assays were performed (table i). c6 was significantly elevated (p = 0.03) at 24h post marathon (7.8%) and remained significantly elevated (p = 0.02) at 72h post exercise (8.8%) (fig. 2). factor b was significantly elevated (p = 0.04) at 72h post exercise (12.8%) (fig. 3). although significantly elevated at 72h post exercise (296.56 ± 35.61 mg/l), this still remained within normative ranges (table i). rf was significantly elevated (p = 0.03) at 72h post exer24h pre ipe 3h post 24h post 72h post time 0 10 20 30 40 50 60 c r p ( m g /l ) fig. 1. alterations in c-reactive protein (mg/dl) of 6 male and 5 female subjects following completion of an ultramarathon. ( signifies p < 0.05 compared with baseline levels.) cise (6.7%) (fig. 4). as with crp, rf at baseline (12.12 iu/ml) was elevated above normative ranges (table i). c4, c3, cic and c1est showed no significant alterations up to and including 72h post exercise, and remained consistently within the normative ranges (table i). plasma volumes changed by –2.66 (±4.04%) immediately post exercise. discussion this study supports previous research in reporting a significantly increased level of the positive app, crp following a strenuous prolonged bout of exercise. crp, a member of the pentraxin family of proteins has traditionally been used in a clinical setting as an indicator of inflammation.7 crp reacts with cell surface receptors to facilitate opsonisation, enhances phagocytosis, acts as a potent stimulator of the complement pathway and modulates polymorphonuclear (pmn) function.10,20,25 crp in the present study was significantly elevated ipe and peaked 24h after the race (fig. 1), a finding mirroring that of strachan et al. 26 and peters et al.21 whilst prolonged strenuous exercise such as marathon running seems to elicit a reaction analogous to an apr, research by fallon et al.12 has shown that the training typical of elite female netball and soccer teams is not associated with significant changes in crp. following 9 months of training, the resting levels of crp in the netball and soccer players was 1.66 mg/l (± 0.89) and 1.62 mg/l (± 1.32) respectively. conversely meyer et al.18 showed a significant increase in crp 24h following an anaerobic cycling session. it was suggested that athletes/physicians should interpret these elevated levels of crp as a sign that the inflammatory response has not resolved and thus the athlete should reduce or limit the number of sessions that induce this response. crp at baseline (24h premarathon) was slightly elevated above the normal range (table ii). these are norms established for the general south african population and not specifically for sportsmen/women. due to the nature of the sport, the elevated crp levels at rest (5.10 ± 3.08 mg/l) could be attributed to cumulative exercise-induced muscle damage. the average individual has a crp concentration of 2 mg/l and whilst concentrations greater than 5 mg/l have been associated with acute infections, anything less than 10 mg/l has been regarded as clinically unimportant.10 this raises the question of whether athletes have elevated resting levels of crp as a result of sports medicine vol 16 no.2 2004 19 table i. normative ranges variable normative ranges c-reactive protein (mg/l) < 5 c3 (g/l) 0.5 1.53 c4 (g/l) 0.2 1.00 c6 (mg/l) 45 96 factor b (mg/l) 191 382 c1-esterase inhibitor (mg/dl) 31 43 circulating immune complexes (µg/ml) < 5 rheumatoid factor (iu/ml) < 11 c 6 ( m g /l ) 24h pre ipe 3h post 24h post 72h post time 58 60 62 64 66 68 70 72 74 76 78 80 82 24h pre ipe 3h post 24h post 72h post time 220 230 240 250 260 270 280 290 300 310 320 330 340 f a c to r b ( m g /l ) fig. 2. alterations in c6 (mg/l) of 6 male and 5 female subjects following completion of an ultramarathon. ( signifies p < 0.05 compared with baseline levels.) fig. 3. alterations in factor b (mg/l) of 6 male and 5 female subjects following completion of an ultra-marathon. ( signifies p < 0.05 compared with baseline levels). 24h pre ipe 3h post 24h post 72h post time 10 11 12 13 14 15 16 17 18 19 r h e u m a to id f a c to r (i u /m l) fig. 4. alterations in rheumatoid factor (iu/ml) of 6 male and 5 female subjects following completion of an ultramarathon. ( signifies p < 0.05 compared with baseline levels.) 20 sports medicine vol 16 no.2 2004 continuous chronic exercise. if so, does the increased crp serve to provide the host with an 'enhanced' immune function, or does it merely represent an adaptation to the continuous inflammation experienced as a result of mechanical stress? crp exhibits both pro and anti-inflammatory actions. whilst it is involved in activating complement and opsonising bacteria/pathogens/debris7 (pro-inflammatory), its net effect is anti-inflammatory in that it has been shown to prevent adhesion of neutrophils to endothelial cells, to inhibit the generation of superoxide by neutrophils and to stimulate the synthesis of interleukin-1 receptor antagonist.10 thus, it is arguable that the increased crp may serve to limit the negative effects associated with repeated bouts of exercise. although elevated resting levels of crp were shown in this study and have been shown elsewhere,14,27 more studies seem to be revealing that athletes exhibit a chronic training/exercise-induced reduction in resting crp concentrations.17,22,29 whether these suppressed resting levels of crp increase an individual's susceptibility to infection remains to be investigated. prolonged and/or strenuous exercise is associated with muscle damage/trauma. 4,13 this disruption of homeostasis activates complement, a pathway that is central to the development of inflammation. complement serves to control inflammatory reactions and chemotaxis, assists with the clearance of immune complexes, activates cells and elicits antimicrobial defences.1, 23 c6, a less-researched terminal complement component, forms part of the membrane attack complex (mac) and was significantly elevated at 24h and 72h after the race (fig. 2). although c5 was not measured in the present study, previous research has shown c5a (the active inflammatory mediator of c5) to be significantly elevated following exercise.2 this would imply an increase in c5, which forms the beginning of the mac. elevation of c6 in the present study, combined with previous research results indicating elevation in c5a, would seem to indicate that formation of the mac accompanies strenuous exercise. the formation of the mac following strenuous exercise could ultimately serve to destroy and assist in clearing the by-products of proteolysis and/or haemolysis. factor b, a c3 convertase enzyme, was significantly elevated 72h after the race (fig. 3). dufaux and order 8 proposed that the classical pathway of complement was activated following prolonged exercise. c3b deposited by the classical pathway can bind to factor b, the enzyme involved in activating the alternate pathway of complement.15,23 thus it seems tenable that the alternate pathway as well as the classical pathway (initiated by crp binding to debris/endotoxins) are initiated following strenuous exercise. rf was significantly elevated 72h after the race (fig. 4). although rf peaked ipe no significance was reported, possibly due to the large subject variation at this measurement. interestingly, as with crp, rf was consistently elevated above the normal ranges. rf (igm anti-igg autoantibody) initiates inflammatory processes and is specific for a determinant on the fc portion of the subjects' own igg molecules. the complexes formed between rf and igg are deposited in the synovia of joint spaces where they activate complement pathways and thus chemotactic factors that attract granulocytes.15 the elevated rf at 72h after the race would imply that the immune/inflammatory response to the strenuous exercise had not yet resolved. this should be taken into consideration when monitoring and interpreting changes in immunoglobulin (igg and igm) levels following exercise. the present study showed no significant alterations in c1est, c3 and c4. studies have consistently yielded inconsistent results when it comes to monitoring the alterations in complement concentration following exercise. in a study conducted by dufaux and order,8 2.5 hours of running was adequate to elicit significant changes in c3a and c4a anaphylatoxins, the active components of c3 and c4 respectively. these changes were observed in moderately trained athletes. a similar response of c3a and c4a was shown in another study by dufaux et al.9 where the concentration of these complement components was significantly elevated immediately following a graded cycle ergometer test to exhaustion. in addition, camus et al.2 found a significant increase in c5a following 20 minutes of cycling at 80% of vo2max. however, thomsen et al. 28 showed no significant changes in complement cleaved products (c3c and c3d) in 14 untrained volunteers who completed a 60 minute cycle test at 75% of vo2max. it was hypothesised by camus et al. 2 that previous studies had failed to show changes in c5a due to the nature of the intervention (exercise and intensity) and also the turnover rate of this protein. it is tenable that this hypothesis could apply to the present study as within 3h post exercise, c1est, c3 and c4 were below pre-race levels. clearly, the conflicting results with regard to complement response following exercise requires further elucidation. when comparing and interpreting the complement response to exercise, the mode, intensity, duration of the activity as well as experience of the athletes should be taken into consideration. a study conducted by king et al.16 emphasises this point as it was found that certain activities such as jogging and aerobic dancing were characterised by a decreased possibility of elevated inflammatory markers. although the study did not take into account the duration and intensity of the exercise, activities such as swimming, cycling and weight -lifting did not exhibit the same association. in addition, nieman et al.19 have shown that resting as well as post-exercise levels of complement differ in athletes and sedentary controls. no significant alterations in circulating immune complexes were found in the present study. soluble antigens form antibody:antigen complexes known as immune complexes.23 table ii. acute phase reactants showing no significant changes post exercise (mean ± se) 24h pre ipe 3h post 2h post 72h post c4 (g/l) 0.27 0.24 0.23 0.20 0.21 (± 0.03) (± 0.04) (± 0.04) (± 0.01) (± 0.01) c3 (g/l) 1.10 1.15 1.04 1.00 1.02 (± 0.12) (± 0.11) (± 0.07) (± 0.05) (± 0.05) cic (ug/ml) 1.57 1.43 1.51 1.32 1.29 (± 0.15) (± 0.16) (± 1.36) (± 0.12) (± 0.10) c1est (mg/dl) 23.51 25.53 23.32 23.78 24.62 (± 0.75) (± 1.87) (± 0.61) (± 0.92) (± 0.77) cic = circulating immune complexes; c1est = c1-esterase; ipe = immediately post exercise. sports medicine vol 16 no.2 2004 21 thus each time antigen meets an antibody, an immune complex is formed.15 these antigens include (amongst others) debris from dead micro-organisms and are removed from circulation via complement activation. one might expect that damage caused as a result of prolonged, strenuous exercise to muscles, connective tissue and erythrocytes results in the formation of excessive immune complexes. the results, however, show that cic were consistently below the normal range following the ultramarathon (table i). although cic are not strictly classified as acute phase reactants, they can be seen as residual products of an apr and could thus provide information regarding the effectiveness of complement pathways to mediate their removal. 24 the non-significant changes in cic could arguably be attributed to the efficient functioning of macrophages in rapidly removing the immune complexes from circulation and would be in keeping with elevated levels of crp. this could also explain why little changes in complement concentrations were observed. in summary, this study showed that crp was significantly elevated immediately after an ultramarathon (90 km) and peaked 24h post marathon. crp and rf were elevated above the normal ranges both at baseline and at subsequent measurements. the raised resting levels of crp could imply that the athletes were training too close to the race, and that correct tapering was not implemented. since certain app were only elevated at 72h it is proposed that future studies should measure app over a more extended period and at shorter intervals to obtain a comprehensive overview of the acute phase inflammatory response to exercise. references 1. benjamini e, sunshine g, leskowitz s. complement. in: immunology: a short course. iii. new york: wiley-liss, 1996: 245-59. 2. camus g, duchateau j, dupont-deby g, et al. anaphylatoxin c5a production during short-term submaximal dynamic exercise in man. int j sports med 1994; 15(1): 32-5. 3. cannon jg, meydani sn, fielding ra, et al. acute phase response in exercise ii. associations between vitamin e, cytokines and muscle proteolysis. am j physiol 1991; 260: 1235-9. 4. deschenes mr, brewer re, bush ja, mccoy rw, volek js, kraemer wj. neuromuscular disturbance outlasts other symptoms of exercise-induced muscle damage. j neurol sci 2000; 174: 92-9. 5. dill db, costill dl. calculation of percentage changes of blood, plasma and red cells in dehydration. j appl physiol 1974; 37: 247-8. 6. dinarello ca. interleukin-1 and the pathogenesis of the acute-phase response. n engl j med 1984; 311: 1413-8. 7. du clos tw. function of c-reactive protein. ann med 2000; 32: 274-8. 8. dufaux b, order u. complement activation after prolonged exercise. clin chim acta 1989; 179: 45-50 9. dufaux b, order u, liesen h. effect of short maximal physical exercise on coagulation, fibrinolysis and complement. int j sports med 1991; 12: 3842. 10. epstein fh. acute phase proteins and other systemic responses to inflammation. n engl j med 1999; 340: 448-54. 11. fallon ke. the acute phase response and exercise: the ultra-marathon as prototype exercise. clin j sport med 2001; 11: 38-43. 12. fallon ke, fallon sk, boston t. the acute phase response and exercise: court and field sports. br j sports med 2001; 35: 170-3. 13. fridén j, sjostrom m, ekblom b. myofibrillar damage following intense exercise in man. int j sports med 1983; 4: 170-6. 14. gleeson m, almey j, brooks s, cave r, lewis a, griffiths h. haematological and acute-phase responses associated with delayedonset muscle soreness in humans. eur j appl physiol 1995; 71: 137-42. 15. janeway ca, travers p, walport m, shlomchik m. immunobiology. the immune system in health and disease. 5th ed. new york: garland publishing, 2001. 16. king de, carek p, mainous ag, pearson ws. inflammatory markers and exercise: differences related to exercise type. med sci sports exerc 2003; 35: 575-81. 17. mattusch f, dufaux b, heine o, mertens i, rost r. reduction of the plasma concentration of c-reactive protein following nine months of endurance training. int j sports med 2000; 21: 21-4. 18. meyer t, gabriel hw, ratz m, muller hj, kindermann w. anaerobic exercise induces moderate acute phase response. med sci sports exerc 2000; 33: 549-55. 19. nieman dc, tan sa, lee jw, berk ls. complement and immunoglobulin levels in athletes and sedentary controls. int j sports med 1989; 10: 124-8. 20. pepys mb, baltz ml. acute phase proteins with special reference to creactive protein and related proteins (pentaxins) and serum amyloid a protein. adv immunol 1983; 34: 141-99. 21. peters em, anderson r, theron aj. attenuation of increase in circulating cortisol and enhancement of the acute phase protein response in vitamin c-supplemented ultramarathoners. int j sports med 2001; 22: 120-6. 22. petibois c, cazorla g, déléris g. the biological and metabolic adaptations to 12 months training in elite rowers. int j sports med 2003; 24: 36-42. 23. roitt i, brostoff j, male d. immunology. 6th ed. edinburgh: mosby, 2002. 24. schifferli ja, taylor rp. physiological and pathological aspects of circulating immune complexes. kidney int 1989; 35: 993-1003. 25. schultz dr, arnold pi. properties of four acute phase proteins: c-reactive protein, serum amyloid a, (1-acid glycoprotein, and fibrinogen. semin arthritis rheum 1990; 20: 129-47. 26. strachan af, noakes td, kotzenberg g, et al. c-reactive protein concentrations during long distance running. bmj 1984; 29: 1249-51. 27. taylor c, rogers g, goodman c, et al. hematologic, iron-related, and acute-phase protein responses to sustained strenuous exercise. j appl physiol 1987; 62: 464-9. 28. thomsen bs, rodgaard a, tvede n, et al. levels of complement receptor type one (cr1, cd35) on erythrocytes, circulating immune complexes and complement c3 split products c3d and c3c are not changed by short term physical exercise or training. int j sports med 1992; 13: 172-5. 29. tomaszewski m, charchar fj, przybycin m, et al. strikingly low circulating crp concentrations in ultra-marathon runners independent markers of adiposity. how low can you go? arterioscler thromb vasc biol 2003; 23: 1640-4. 30. weight lm, alexander d, jacobs p. strenuous exercise analogous to the acute-phase response? clin sci 1991; 81: 677-83. sajsm vol. 28 no. 1 2016 23 original research reliability and concurrent validity of an alternative method of lateral lumbar range of motion in athletes mark d hecimovich,1 phd; jeffrey j hebert,2 phd 1 university of northern iowa, division of athletic training, 003c human performance center, cedar falls, iowa, usa 2 murdoch university, school of psychology and exercise science, 90 south street, murdoch, western australia, 6150 corresponding author: mark hecimovich (mark.hecimovich@uni.edu) background: cricket bowling involves combined spinal movements of side bending and rotation and, consequently, injury to the low back is a common problem. therefore the assessment of lumbar spine kinematics has become a routine component in preseason screening. this includes static measurement of lateral spinal flexion as asymmetrical range of motion may predispose an athlete to low back injury. objectives: this study examined intra-rater reliability and concurrent validity of the fingertip-to-floor distance test (ffd) when compared to a criterion range of motion measure. methods: thirty-four junior-level cricket players aged 13-16 years were recruited. lumbar spine lateral flexion was measured simultaneously with the fingertip-to-floor distance test and digital inclinometry methods. relative and absolute intra-rater reliability were investigated with intraclass correlation coefficients (icc3,1) of agreement, standard error of measurement (sem) estimates, bland and altman bias estimates and 95% limits of agreement, respectively. the concurrent validity of the fingertip-to-floor distance test, compared to digital inclinometry measures, was examined with pearson correlation coefficients. results: intra-rater reliability demonstrated substantial agreement for both measures (icc3,1 > 0.84). the fingertip-to-floor distance test sem values ranged from 1.71-2.01 cm with an estimated minimum detectable change (mdc) threshold of 4.73-5.55 cm. the inclinometry sem values ranged from 1.00-1.09° with minimal detectable change estimates of 2.77-3.01°. there were strong correlations between the index test and criterion measure outcomes (r > 0.84, p < 0.001). conclusions: this study’s results support the intra-rater reliability and concurrent validity of the finger-to-floor distance test, suggesting it to be a suitable surrogate measure for lumbar lateral flexion testing. keywords: authenticity, efficacy, range of motion, lumbar spine s afr j sports med 2016;28(1):23-26. doi:10.17159/2078-516x/2016/v28i1a745 injury to the low back is a common problem in sporting populations[1] and more so in sports such as hockey,[2] cricket,[3] tennis[4] and sweep rowing[5] which involve combined spinal movements of side bending and rotation. consequently the assessment of lumbar spine kinematics has become a routine component in preseason screening.[6,7,3] tests include static measurement of lateral spinal flexion[7] as the asymmetrical range of motion may predispose an athlete to low back injury or be the result of a previous low back injury.[3] for example, it is accepted practice to measure lateral lumbar flexion in cricket players.[7] in a sport such as cricket, considered to be a relatively low injury sport, only around five per cent of elite players are unavailable to play due to injury at any given time.[8,9] however, epidemiological studies in south africa[10] have demonstrated that fast bowlers, who have an injury prevalence of approximately 15%,[9] have the highest risk of injury in cricket, with the low back being most susceptible to both traumatic and overuse injuries.[11] the reason for this is the inherent, high-load biomechanical nature of the bowling action[9,12] which may place undue stress on the pars interarticularis during the delivery stride due to large contralateral lumbar side-flexion motion coupled with large ground reaction forces.[13] the high prevalence of injury among fast bowlers[9,12] highlights the great need for research into factors associated with injury. both extrinsic and intrinsic factors work in combination to predispose the bowler to injury.[14,15] extrinsic or environment-related factors include bowling workload (the numbers of overs a bowler bowls), player position (first, second or third change) and time of play (morning or afternoon).[14,15] intrinsic, or person-related, factors include flexibility (range of motion) muscle strength, balance and biomechanics.[14,15] young cricket players have a greater risk of injury to the back compared to adult cricket players. successful prevention strategies for both adult and young players have been developed. these include identifying injury risk factors associated with physical characteristics to understand why an athlete may be predisposed to low back injury.[16,17] this has led to pre-participation screening protocols.[16] these protocols are commonly used to measure potential injury risk factors[17] that may predispose an athlete to low back injury. included in these protocols are spinal and extremity range of motion, pelvic control, balance, and hip strength.[6,7] currently, measurements such as spinal range of motion in lumbar lateral flexion and trunk rotation are obtained to measure asymmetries.[7] these measurements can be used in a prospective analysis of any injuries during a season.[7] measures of active lumber spine range of motion can be obtained with a number of methods including visual observation, tape measure/ruler, goniometry, linear measures, and inclinometry.[18] the method of assessment varies among clinicians and institutions based on factors such as time, educational inclination of the clinician, availability of equipment, and the specific movement or tissue being assessed.[18] digital inclinometry is recognised as a reliable and valid measure of joint range of motion.[19-21] however, this technology is expensive and not widely available to clinicians. as a result, measuring the fingertip-to-floor distance (ffd) for attainment of lateral spinal flexion of motion has been advocated as a suitable surrogate for digital inclinometry. consequently, the ffd test is currently recommended by the cricket australia national physiotherapy working group to quantify lateral lumbar spine range of motion as part of the annual preseason cricket screening program to allow a prospective analysis of any injuries suffered during a season.[7] a preliminary report indicates the ffd test has an acceptable degree of measurement error.[7] however, a comprehensive investigation of ffd test reliability has not been undertaken and its level of concurrent validity compared to an accepted criterion standard is unknown. therefore, the aim of this study was to examine the mailto:mark.hecimovich@uni.edu http://dx.doi.org/10.17159/2078-516x/2016/v28i1a745 24 sajsm vol. 28 no. 1 2016 intra-rater reliability of the ffd test as well as its concurrent validity compared to digital inclinometry when measuring lumbar spine lateral flexion among a cohort of junior-level cricket players. methods ethics the study protocol was approved by the murdoch university human research ethics committee (2013/110) and all participants provided written consent prior to study enrolment. participants thirty-eight participants were recruited from members of the talented athlete program of the western australian cricket association. potential participants who reported a current history of spinal injury were excluded. all the participants recruited were required to undergo the annual preseason screening; however, this application may be used across all age and skill levels. procedures for this study, lateral flexion of the lumbar spine was measured using two methods simultaneously. the index test was the ffd test at maximal lateral flexion. the criterion comparison was lumbar lateral flexion range of motion testing using dual digital inclinometry. both methods were performed in a standing position with measures obtained by two examiners in a manner consistent with the national physiotherapy screening protocol[7] and performed twice. the examiners underwent a two-hour training session in both methods given by a skilled professional of the methods. they were required to perform each method satisfactorily before being allowed to participate as examiners in the study. fig. 1a: starting position for fingertip-to-floor distance test fig. 1b: end position for fingertip-to-floor distance and digital inclinometry measurement participants were guided through a warm-up before the measurements were recorded. the warm-up included a one-minute slow jog, seated lower extremity stretching which incorporated spinal flexion and rotation, and standing rotational and side bend stretching. the stretches were not taken to the participants’ end range of motion. for both methods (figs. 1a and 1b) participants stood barefoot with feet hip distance apart, with the contralateral base of fifth metatarsal and greater trochanter touching the wall. the arm nearest the wall was abducted, with the elbow comfortably flexed so that the participant did not push away from the wall. the participant was then instructed to ‘slowly run your fingers down the outside of your leg and reach as far as you can while continuing to look straight ahead ’. the participant maintained contact with the wall with both feet flat on the floor at all times. the participant laterally flexed at the trunk without a trunk or hip flexion or extension. the range of motion outcomes were measured bilaterally and categorised as front foot or back foot according to the participant’s bowling side (throwing side). for the index test, upon completion of the lateral flexion movement, the examiners used their finger to set the zero mark of the tape on the floor vertically below the mark on the participant’s leg and level with base of the fifth metatarsal. while positioned side-on to the player, the examiner held the tape measure vertically and pulled it taut so that the tape was in contact with the participant’s skin at the mark on their leg. the tape was then pulled taut along the contour of the leg up to the range of motion mark on the participant’s leg. the criterion test involved range of motion measures obtained with a dualer iq digital dual inclinometer (jtech medical, salt lake city, ut, usa), with primary and secondary sensors. with the participants standing in a neutral posture, the primary sensor was placed at the t12 spinal level with the secondary sensor placed sajsm vol. 28 no. 1 2016 25 at sacral midpoint. once the participant reached their maximum lateral spinal flexion the range of motion measurement was recorded from the primary sensor by the second examiner. data were analysed with ibm spss version 21.0 software (ibm corp, armonk, ny). the relative and absolute intra-rater reliability of the index and criterion measures were examined by the authors. relative reliability was examined with model 3 agreement intra-class correlation coefficients of a single repetition (icc3,1). icc values greater than 0.75 are interpreted as indicating ‘excellent’ to ‘good’ reliability and those below 0.75 ‘poor’ to ‘moderate reliability’.[22] absolute reliability was examined with the standard error of measurement (sem).[22] the sem estimates the variability of repeated measurements and is calculated from the sample standard deviation and the icc (sem = sd√1 – icc). levels of minimal detectable change (mdc) from the sem were calculated using the following formula: 1.96 x √ 2 x sem.[22] the mdc represents the smallest degree of change that exceeds measurement error and is used by clinicians to distinguish true change from change resulting from error. finally, bland and altman plots were created and bias statistics calculated, and 95% limits of agreement.[23] to investigate the concurrent validity of the ffd test, the relationship of the test outcome was examined with the concurrent digital dual inclinometry measures using pearson correlation coefficients. alpha was 0.05 for all analyses. results thirty-four participants (27 male, 7 female) were enrolled with mean (sd) age = 14 (1) years, height = 172.0 (9.3) cm, weight = 62.0 (8.6) kg; and bmi = 21.6 (0.3) kg/m2. the intra-rater reliability analyses indicated substantial agreement for both measures (table 1). the sem for the front foot and back foot tape measure were 2.01 cm and 1.71 cm respectively with mdc estimates ranging from 5.55 cm (front foot) to 4.73 cm (back foot). the sem for front foot and back foot inclinometry measures were 1.00  degrees and 1.09  degrees with mdc estimates of 2.77 degrees (front foot) and 3.01 degrees (back foot). front foot limits of agreement (loa) were 2.53 cm (-0.74–5.80) and 1.17 degrees (-0.53–2.87) and back foot 2.14 cm (-0.62–4.90) and 1.14 degrees (-1.0–3.2), respectively table 1. intra-examiner reliability using single measures mean of two measurements for each rating for inclinometry (degrees) and ffd (cm) for front foot and back foot method mean + sd icc3,1* sem mdc bias (95% loa) ff cm 44.23 + 5.07 .84 2.01 cm 5.55 cm 2.53† (-0.74,5.80) ff degrees 12.94 + 3.91 .93 1.00 degrees 2.77 degrees 1.17† (-0.53,2.87) bf cm 43.98 + 4.59 .86 1.71 cm 4.73 cm 2.14† (-0.62,4.90) bf degrees 12.81 + 3.97 .92 1.09 degrees 3.01 degrees 1.14† (-1.0,3.2) *absolute agreement icc interpretation: .91-1.0 (excellent reliability); .76-.90 (good reliability); .51-.75 (moderate reliability); .00-.50 (poor reliability) †p < 0.05 mdc – minimal detectable change loa – limits of agreement table 2. correlations between for inclinometry (degrees) and ffd (cm) for front foot and back foot for time 1 and time 2 method ff (degrees) 1 ff (degrees) 2 bf (degrees) 1 bf (degrees) 2 ff (cm) 1 .842* ff (cm) 2 .980* bf (cm) 1 .862* bf (cm) 2 .987* *p < 0.05 n = 34 the results from the concurrent validity analyses are presented in table 2. there were strong correlations between the index test and criterion measure (r > 0.84, p < 0.001). discussion the intra-rater reliability of two measurement methods for standing lateral spinal flexion was examined as well as the concurrent validity of a new test for lateral lumbar flexion range of motion in a cohort of healthy juniorlevel athletes. this was the first study to fully explore for potential sources of measurement error in the ffd test as well as to examine its validity by comparing its results with an accepted criterion standard.[24] this study’s results support the intra-rater reliability (icc3,1 = 0.84-0.86) and concurrent validity of the ffd as demonstrated by its strong associations with the criterion measure (r = 0.84-0.99). this result suggests the ffd test to be a suitable surrogate measure for lumbar lateral flexion testing. this is consistent with a previous reliability analysis of the ffd test that reported substantial intra-rater reliability (icc > 0.88).[7] however, there were several important measurement issues identified in the current study. first, both the ffd and digital inclinometry measures exhibited a positive bias between repetitions, indicating a source of systematic error. this means that the range of motion was greater during repetition two than repetition one, irrespective of measurement method. this finding suggests that to achieve measurement stability it is necessary to perform a series of ‘warm-up’ repetitions prior to testing lateral lumbar flexion range of motion. this practice is not part of current recommendations[7] and therefore additional research is needed to better understand this issue. a comparison of icc values between the two methods indicates the digital inclinometer measures to be more reliable than the ffd test outcomes. however, inspection of the absolute reliability estimates provides additional clarity. when compared to the mean values, the ffd had less error (sem and mdc values) than digital inclinometry. for example, the mdc estimates were between 11-13% of the mean value for the ffd test and 21-24% for digital inclinometry. this means that compared to the ffd test, approximately twice as much change would need to occur in the inclinometry-derived range of motion measures before one could be confident that the difference resulted from ‘true’ change and not measurement error. a likely explanation for the discrepancy between the relative (icc) and absolute (sem, mdc) reliability outcomes stems from the lower variance estimates observed 26 sajsm vol. 28 no. 1 2016 with the ffd test. low between-person variance depresses icc values, making interpretation difficult. for example, a hypothetical study comparing icc values for measures of elbow range of motion would likely find the iccs of elbow flexion to be higher than for extension. this does not mean that clinicians are more reliable when measuring elbow flexion, but results from the fact that most people can extend their elbow to ~0 degrees, while there is much greater variability in elbow flexion. this limitation is well known[25] and highlights the importance of avoiding sole reliance on icc analyses when making determinations about test reliability. the utility of the ffd test is that it does not require expensive equipment and is easy to administer. however, individual differences in height and arm length are a potential source of bias in this measurement. consequently, the ffd may be most appropriate for the quantification of range of motion change or side-to-side symmetry. for example, if the aim was to measure or monitor changes over time for a single player (effectiveness of a rehabilitation programme or injury) the ffd is ideal. if the aim was to obtain an angular measurement which can be used to compare between groups of players, the digital inclinometer would need to be utilised. both the ffd and digital inclinometer can be used across all populations as the goal is to compare side-to-side measurements for symmetry. study limitations these results should be considered within the study limitations. although the examiners underwent standardised training for each method, the duration of the training was relatively brief (two hours). therefore it is possible that more rigorous training may have enhanced measurement precision.[26,27] another study limitation relates to the external validity of the results. as a cohort of young, healthy athletes was examined, these results should not be generalised to other populations, such as adults with low back pain or injury. further research is needed to determine the optimal methodology for the ffd test, particularly with respect to the potential for systematic error resulting from a lack of measurement stability and the potential effect of a “warm-up” routine. conclusion the high levels of intra-rater reliability (icc3,1 = 0.84-0.86) and concurrent validity (r = 0.84-0.99), demonstrate the ffd to be reproducible and a valid measure of lateral flexion range of motion. measuring lateral flexion, especially for symmetrical side-to-side variations, is important in sports which involve combined spinal movements of side bending and rotation as differences may be a precursor for future injury. thus clinicians can use this test as an alternative to digital inclinometry. this study’s estimates of minimal detectable change demonstrate that approximately five cm of change is necessary before clinicians can be confident that the difference is not the result of measurement error. however, both methods demonstrate a small degree of systematic error (1 degree, 1.7 and 2.1 cm) resulting from an increase in range of motion between repetitions, highlighting the potential importance of an appropriate ‘warm up’ routine prior to measurement. references 1. walker bf, muller r, grant wd. low back pain in australian adults. prevalence and associated disability. j manipulative physiol ther 2004;27(4):238-244. [http://dx.doi. org/10.1016/j.jmpt.2004.02.002] 2. weir mr, smith ds. stress reaction of the pars interarticularis leading spondylolysis: a cause of adolescent low back pain. j adolesc health care 1989;10(6):573-577. [http://dx.doi.org/10.1016/0197-0070(89)90029-6] 3. stuelcken mc, ginn ka, sinclair pj. musculoskeletal profile of the lumbar spine and hip regions in cricket fast bowlers. phys ther sport 2008;9(2):82-88. [http://dx.doi. org/10.1016/j.ptsp.2008.02.002] 4. donatelli r, dimond d, holland m. sport-specific biomechanics of spinal injuries in the athlete (throwing athletes, rotational sports, and contact-collision sports). clin sports med 2012;31(3):381-396. [http://dx.doi.org/10.1016/j.csm.2012.03.003] 5. strahan ad, burnett af, caneiro jp, et al. differences in spinopelvic kinematics in sweep and scull ergometer rowing. clin j sport med 2011;21(4):330-336. [http:// dx.doi.org/10.1097/jsm.0b013e31821a6465] 6. dennis rj, finch cf, elliott bc, et al. the reliability of musculoskeletal screening tests  used in cricket. phys ther sport 2008;9(1):25-33. [http://dx.doi.org/10.1016/j. ptsp.2007.09.004] 7. cricket australia sport science sport medicine unit. national physiotherapy screening protocol for 2013-14. brisbane, aus, 2013. 8. mansingh a, harper l, headley s, et al. injuries in west indies cricket 2003-2004. br j sports med 2006;40(2):119-123. [http://dx.doi.org/10.1136/bjsm.2005.019414] 9. orchard jw, james t, portus mr. injuries to elite male cricketers in australia over a 10-year period. j sci med sport 2006;9(6):459-467. [http://dx.doi.org/10.1016/j. jsams.2006.05.001] 10. stretch ra. cricket injuries: a longitudinal study of the nature of injuries to south african cricketers. br j sports med 2003;37(3):250-253. [http://dx.doi.org/10.1136/ bjsm.37.3.250] 11. weatherley cr, hardcastle ph, foster dh. cricket. in: watkins r (ed.). the spine in sports. st louis (mo): mosby, 1996;:414-429. 12. frost wl, chalmers dj. injury in elite new zealand cricketers 2002-2008: descriptive epidemiology. br j sports med 2014;48(12):2-7. [http://dx.doi. org/10.1136/bjsports-2012-091337] 13. johnson m, ferreira m, hush j. lumbar vertebral stress injuries in fast bowlers: a review of prevalence and risk factors. phys ther sport 2012;13(1):45-52. [http:// dx.doi.org/10.1016/j.ptsp.2011.01.002] 14. orchard jw. intrinsic and extrinsic risk factors for muscle strains in australian football. am j sports med 2001;29(3):300-303. 15. mcbain k, shrier i, shultz r, et al. prevention of sport injury ii: a systematic review of clinical science research. br j sports med 2012;46(3):174-179. [http://dx.doi. org/10.1136/bjsm.2010.081182] 16. finch c. a new framework for research leading to sports injury prevention. j sci med sport 2006;9(1):3-9. [http://dx.doi.org/10.1016/j.jsams.2006.02.009] 17. difiori j. overuse injuries in children and adolescents. phys sportsmed 1999;27(1):75-89. [http://dx.doi.org/10.3810/psm.1999.01.652] 18. clarkson hm. head, neck, and trunk. in: clarkson hm (eds.). joint motion and function assessment: a research based practical guide. philadelphia, pa: lippincott williams & wilkins, 2005;:223-276. 19. de winter af, heemskerk ma, terwee cb, et al. inter-observer reproducibility of measurements of range of motion in patients with shoulder pain using a digital inclinometer. bmc musculoskelet disord 2004;14:5-18. [http://dx.doi. org/10.1186/1471-2474-5-18] 20. prushansky t, deryi o, jabarreen b. reproducibility and validity of digital inclinometry for measuring cervical range of motion in normal subjects. physiother res int 2010;15:42-48. [http://dx.doi.org/10.1002/pri.443] 21. sohn j-h, choi h-c, lee s-m, et al. differences in cervical musculoskeletal impairment between episodic and chronic tension-type headache. cephalalgia 2010;30(12):1514-1523. [http://dx.doi.org/10.1177/0333102410375724] 22. portney lg, watkins mp. foundations of clinical research: applications to practice. 3rd ed. philadelphia, pa: fa davis company, 2015. 23. atkinson g, nevill am. statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine. sport med 1998;26(4):217-238. [http://dx.doi.org/10.2165/00007256-199826040-00002] 24. american medical association guides to the evaluation of permanent impairment. 5th ed. chicago, il: ama, 2000. 25. de vet hcw. measurement in medicine: a practical guide. cambridge, uk: cambridge university press, 2011. [http://dx.doi.org/10.1017/cbo9780511996214] 26. brunse mh, stochkendahl mj, vach w, et al. examination of musculoskeletal chest pain – an inter-observer reliability study. man ther 2010;15(2):167-172. [http:// dx.doi.org/10.1016/j.math.2009.10.003] 27. cibere j, thorne a, bellamy n, et al. reliability of the hip examination in osteoarthritis: effect of standardization. arthritis rheum 2008;59(3):373-381. [http://dx.doi.org/10.1002/art.23310] http://dx.doi.org/10.1016/j.jmpt.2004.02.002 http://dx.doi.org/10.1016/j.jmpt.2004.02.002 http://dx.doi.org/10.1016/0197-0070(89)90029-6 http://dx.doi.org/10.1016/j.ptsp.2008.02.002 http://dx.doi.org/10.1016/j.ptsp.2008.02.002 http://dx.doi.org/10.1016/j.csm.2012.03.003 http://dx.doi.org/10.1097/jsm.0b013e31821a6465 http://dx.doi.org/10.1097/jsm.0b013e31821a6465 http://dx.doi.org/10.1016/j.ptsp.2007.09.004 http://dx.doi.org/10.1016/j.ptsp.2007.09.004 http://www.ncbi.nlm.nih.gov/pubmed/16431997 http://www.ncbi.nlm.nih.gov/pubmed/16431997 http://dx.doi.org/10.1136/bjsm.2005.019414 http://dx.doi.org/10.1016/j.jsams.2006.05.001 http://dx.doi.org/10.1016/j.jsams.2006.05.001 http://dx.doi.org/10.1136/bjsm.37.3.250 http://dx.doi.org/10.1136/bjsm.37.3.250 http://dx.doi.org/10.1136/bjsports-2012-091337 http://dx.doi.org/10.1136/bjsports-2012-091337 http://dx.doi.org/10.1016/j.ptsp.2011.01.002 http://dx.doi.org/10.1016/j.ptsp.2011.01.002 http://dx.doi.org/10.1136/bjsm.2010.081182 http://dx.doi.org/10.1136/bjsm.2010.081182 http://dx.doi.org/10.1016/j.jsams.2006.02.009 http://dx.doi.org/10.3810/psm.1999.01.652 http://dx.doi.org/10.1186/1471-2474-5-18 http://dx.doi.org/10.1186/1471-2474-5-18 http://dx.doi.org/10.1002/pri.443 http://dx.doi.org/10.1177/0333102410375724 http://dx.doi.org/10.2165/00007256-199826040-00002 http://dx.doi.org/10.1017/cbo9780511996214 http://dx.doi.org/10.1016/j.math.2009.10.003 http://dx.doi.org/10.1016/j.math.2009.10.003 http://dx.doi.org/10.1002/art.23310 jsm0404pg000ed. sports medicine vol 16 no.1 2004 33 introduction in the last 10 years sport in general and rugby in particular, has become increasingly professional, resulting in players being paid to participate in the sport. large companies have seen the marketing potential, through worldwide media television and sponsorship, and players have used the opportunity to make rugby a career. as inter-company competition to sponsor rugby teams has increased, so has the money involved in the sport. all these factors have led to great competitiveness between players, with individuals striving to become the best player in their club, province and country. this has resulted in rugby becoming more professional especially at international level, in improved training techniques, and in greater physical demands on the players. according to powell19 and pritchett20 approximately 13% of high school and college football injuries involve the knee. well over 1 000 000 americans participate in organised contact football and over 500 000 south africans in rugby union each year. johnston and paulos11 stated that the potential for lost playing time and the cost of providing medical care for knee injuries, not to mention the impact on a young athlete's life, make the pursuit of injury-reducing factors worthwhile. a variety of protective and supportive knee devices have been devised because of the high incidence of injuries to this joint. prophylactic knee braces are designed to prevent or reduce the severity of knee injuries by absorbing the valgusproducing forces.6,15,16,22 these braces have gained tremendous popularity in the last decade, and team physicians and coaches have prescribed or required brace-wearing by athletes, hoping to prevent injuries and improve performance.9,21 branch and hunter3 and mcnaire et al.14 examined joint kinematics and muscle activity. they compared braced with nonbraced conditions and observed an increase in electromyographic activity and joint kinematics during functional tasks. however, biomechanical studies examining impacts on cadavers/surrogates have shown that braces are effective only during impacts in which the associated forces are much lower than those experienced in the sporting environment.14,17 based on these findings, it has been suggested that proprioception may be improved with the application of a prophylactic knee brace, and this may be responsible for the decrease in knee injuries recorded with brace wearing.3,11,13 this was supported in swash22 and barrett et al.2 who have shown that elastic bandaging improves proprioception in osteoarthritic and replaced knees. original research article the effect of prophylactic knee bracing on proprioception performance in first division rugby union players t h kruger (bsc hons biokinetics, msc sports injuries) m f coetsee (bsc hons biokinetics, msc, phd) s davies (ba hons, ma ergonomics, phd) department of human movement science, university of zululand, empangeni, kwazulu-natal correspondence: t kruger p o box 51421 wierdapark 0149 tel: 072-199 0388, 012-654 0504 fax: 012-654 0504 e-mail: theo@universe.co.za abstract objective. to investigate the effects of prophylactic knee bracing on proprioceptive performance among first division rugby union players during a 2-minute wilknox quad time logger balancing task. design. each subject performed a 2-minute balancing task on the wilknox quad time logger. test order, left or right leg, and the sequence of brace or non-brace, were randomised. subjects were placed on the balancing board and instructed to balance for 2 minutes. subjects performed 6 trials. two days elapsed between testing. each testing day involved 2 trials, 1 trial with and 1 without the prophylactic knee brace. settings. testing took place at the biokinetics laboratory of the university of zululand. subjects. thirty playing (not injured) male rugby players, aged 22 30 years, participating in the kwazulu-natal club championships (2000). outcome measure. performance was measured in terms of time that balance was lost in a dynamic balance test. peak proprioception was the best balancing performance recorded, and average proprioception the average balancing performance for all trials. results. the findings showed an improvement of 17.9% in average proprioception times and 19.1% in peak proprioception times with the application of a prophylactic knee brace (p < 0.01). conclusion. prophylactic knee bracing improved proprioception performance of playing (uninjured) rugby players, and therefore may be responsible for the improvement in knee injury statistics reported in some studies on knee bracing. proprioception is a very difficult parameter to define and measure. traditionally it has been defined as an awareness of joint position in space as sensed by the central nervous system.23 it incorporates joint sensation and spatial orientation.13 the central nervous system receives information from specialised nerve endings, or mechanoreceptors, that are located in the skin, muscle, tendon, joint capsule, and ligaments.1 proprioception is the action-reaction mechanism whereby sensory awareness of changes in the knee joint protect it against harmful forces, which is an important factor in maintaining joint stability. therefore voluntary and spinal reflexes are important in sending messages to the muscles to react and protect the body.23 thus if the muscles are fatigued, voluntary and spinal reflex times increase and proprioception performance decreases, resulting in decreased joint stability and an increase in the probability of injury.18,23 review of the literature allows us to speculate as to the mechanism of improved knee proprioception seen with brace application. certainly, afferent receptors in the skin, muscle, anterior cruciate ligament (acl), and joint capsule exist, and these contribute to proprioceptive input. major position sense receptors in the joint capsule and ligaments, such as free nerve endings and golgi tendon organ stretch receptors, would likely be too deep to be affected significantly by the brace.4,5,8,10,18 the prophylactic brace certainly stimulates the skin during joint motion and also increases the pressure on the underlying musculature and joint capsule. therefore, the most plausible receptors to be involved are the rapidly adapting superficial receptors in the skin and layers beneath muscle such as free nerve endings, hair end organs and merkel's discs. these receptors react strongly to new stimuli, such as movement of the brace on the skin, and adapt quickly once the motion becomes monotonous.4,5,10,18 proprioceptive ability is an important part of running, jumping and tackling and is therefore important for rugby union players throughout the game for a period of 80 minutes. to date, most studies have examined proprioception using static position tasks, where the subject's one limb is positioned at a certain degree angle and the subject is requested to match the position with the other limb. the present study was designed to extend observations by providing a method of examining the ongoing effects of prophylactic knee bracing on the proprioceptive ability of playing (uninjured) rugby players, with no discernable knee pathology, during a 2-minute balancing task. this method could be a more reliable test for rugby union players than the static tests (matching the limb position) done in previous research. methods thirty male subjects playing first league rugby in the kwazulu-natal club championships in 2000 were randomly selected from a group of volunteers (10 forwards and 20 backline players). prior to participation, the testing procedures and risks were fully explained, and all subjects signed an informed consent form. none of the subjects had any knee injuries at the time of the study and subjects were free to withdraw at any time. the ethics committee of the university of zululand, south africa approved the research protocol. proprioception testing was administered in the air-conditioned biokinetics laboratory of the university of zululand, with at least 2 days rest between testing days. the temperature in the biokinetics laboratory was kept at 26°c, and a relative humidity of 45% 55% was maintained. the test was explained and demonstrated to the subjects to ensure that they understood fully so that they could complete the test successfully. before all tests the subjects underwent a 15-minute warm-up, including full body stretching, jogging and sprinting led by the physical trainer of the local rugby team. prior to testing, subjects practised all procedures for 1 minute with and 1 minute without the brace. test order, leg order, and sequence of brace or non-brace, were randomised. standard, off-the-shelf prophylactic knee braces (medac (pty) ltd, cape town, south africa) were used in the study. the basic designs of prophylactic braces are similar, consisting essentially of thigh and calf cuffs connected by hinged bars, which allow for flexion and extension of the knee (figs 1 and 2). the wilknox quad time logger is an electronic wobble board that times the loss of dynamic balance during a 2minute session. it was designed and built at the university of zululand, south africa. the wobble board consists of a round platform with a diameter of 350 mm and a thickness of 30 mm. in the middle of the underside a half sphere with a diameter of 100 mm is attached. the device recorded the time that the edge of the wobble board touched the floor (fig. 3). as the device was developed in the department of human movement science, university of zululand, reliability was verified by means of extensive testing. prior to testing subjects were given a trial run of 1 minute with and without the prophylactic brace. each subject was expected to perform 6 trials in full rugby kit and boots, 3 without the prophylactic brace and 3 with the application of the prophylactic brace. the brace was fitted randomly and the straps were tightened before each trial. subjects were placed on the wilknox quad time logger with their feet parallel to the sides (25 cm apart), and their knees slightly bent. subjects were prohibited from using their hands or other body parts to assist their balance by pushing against their surrounds. subjects were instructed to balance the time logger for a period of 2 minutes; as soon as they were ready, timing started. the average unbalanced time (s) and the peak unbalanced times for the 3 trials in braced v. nonbraced were recorded and used to determine whether differences existed between braced and non-braced conditions. 34 sports medicine vol 16 no.1 2004 a c d b fig. 1. the basic design of knee braces: (a) anterior view, (b) lateral view of thigh and calf cuffs, (c) double hinge, and (d) single hinge. results are expressed as means and standard deviations, along with one-way analysis of variance (anova) and independent t-tests to determine whether significant (p < 0.01) differences occured between test re-test measured parameters. body mass was measured to the nearest 100 g on a deco scale with subjects wearing only a pair of shorts. stature was measured to the nearest millimetre using a stadiometer. subjects stood erect and barefoot, with their weight evenly distributed on both feet and the head in the frankfort horizontal plane. with heels together the subjects were instructed to inhale and stretch upward to the fullest extent. the vertical distance from the vertex to the floor in the mid-saggital plane was measured. percentage body fat was calculated from skinfold measures at four sites: biceps, triceps, supra-iliac and sub-scapula. 7 results subjects' characteristics are given in table i. it is noticeable that the mass and height of the subjects in this study are greater than those of the general population, which is to be expected, as they are a selected group of rugby players and these attributes are essential to performance. being club rugby players, where the selection base is relatively limited, they are smaller and lighter than players in teams competing at a higher level, where the selection base is larger. average and peak proprioceptive performance was recorded. table ii illustrates the average proprioceptive performances in the 3 trials for the forwards as a group, backline players as a group, and the forwards and backs combined as a group with and without the application of a prophylactic brace. the results for all 3 groups showed that the average proprioceptive ability significantly (p < 0.01) increases with prophylactic brace application. the average proprioceptive improvement for backline players was 17%, for the forwards 20% and for the combined group 18%. table iii illustrates the peak proprioceptive performances in the 3 trials for the forwards, backs and the combined group. the peak proprioceptive performance illustrated significant (p < 0.01) improvement for the backline players at 22%, 19% for the forwards and 19% for the combined group. discussion this study investigated the effects of prophylactic knee bracing on the proprioceptive ability of playing (uninjured) first division rugby union players. the poor mechanical performance of braces in resisting impact forces, together with altered kinematics when wearing a brace during sports activsports medicine vol 16 no.1 2004 35 fig. 3. proprioception being measured on the wilknox quad time logger. fig. 2. standard, off-the-shelf, medac prophylactic knee brace. table i. characteristics of subjects (n = 30) in the present study compared with other studies level age (yrs) stature (cm) mass (kg) fat % present study 24.3 (5.0) 182.2 (7.6) 87.5 (12.5) 16.4 (4.0) sa norm 18-34 174.2 68.6 nsw super 12 185.6 99.5 14.7 australia 188.4 101.8 13.2 source: kruger, coetsee, davies, 2003.12 ities, has led some researchers to suggest that proprioception may be the factor responsible for findings of decreased injury when wearing a brace.14 proficiency in balance in this test relies more on the sensory feedback (proprioception) from the muscles and the joint structures of the lower limbs, than on the feedback from the vestibular apparatus in the inner ear. this is achieved by means of the smallness of the ball of the wobble board. subjects need to control the wobble board (keeping the edge from touching the floor) without losing total body balance. overall, prophylactic brace application improved proprioceptive ability. findings from the present study indicate that prophylactic knee bracing improved average proprioception performance significantly (p > 0.01) by 18% and peak proprioceptive ability significantly (p > 0.01) by 19%. these findings are similar to those of barrett et al.2 and mcnaire and colleagues,14 who showed that elastic bandaging which acts as a prophylactic brace, improved proprioceptive ability in subjects with both arthritic and normal knees respectively. this could improve position sense. conclusion the finding of this work supports the research hypothesis that prophylactic knee bracing improves the proprioceptive ability of playing individuals, i.e. players with uninjured knees. given the reported deficiencies of braces in protecting the knee against lateral and medial forces in sport situations, it may be that the improvement in proprioception may be responsible for the decrease in knee injury statistics reported in some epidemiological studies of bracing. references 1. baker be, van hanswyk e, bogosian sp. a biomechanical study of the static stabilizing effect of the knee braces on the medial stability. am j sports med 1989; 17 (2): 182-6. 2. barrett ds, cobb ag, bentley g. joint proprioception in normal osteoarthritic and replaced knees. j bone joint surg am 1991; 73b: 536. 3. branch tp, hunter r. functional analysis of anterior cruciate ligament braces. clin sport med 1990; 9: 771-97. 4. clark fj, burgess rc, chapin jw. role of intramuscular receptors in the awareness of limb position. j neurophysiol 1985; 54: 1529-49. 5. corrigan jp, cashman wf, brady mp. proprioception in the cruciate deficient knee. j bone joint surg am 1992; 74b: 247-50. 6. deppen rj, landfried mj. efficacy of prophylactic knee bracing in high school football players. journal of sports training 1994; 20: 243-6. 7. durnin jvga, womersley j. body fat assessed from total body density and its estimation from skinfold thickness: measurement on 481 men and women aged 16 72 years. br j nutr 1972; 32: 77-97. 8. guyton ac. somatic sensation: the mechanoreceptive sensations. in: textbook of medical physiology. 7th ed. philadelphia: wb saunders, 1986: 588-9. 9. hansen bl, ward jc, diehl rc. the preventive use of the anderson knee stabler in football. physician of sports medicine 1985; 13: 75-81. 10. horch kw, clark fj, burgess pr. awareness of joint angle under static conditions. j neurophysiol 1975; 38: 1436-47. 11. johnston jm, paulos le. prophylactic lateral knee braces. med sci sports exerc 1991; 23: 783-7. 12. kruger th, coetsee mf, davies she. the effect of prophylactic knee bracing on selected performance parameters. african journal of physical health education and recreational dance 2003; 9 (1): 40-51. 13. lephart sm, pincivero dm, giraldo jl. the role of proprioception in the management and rehabilitation of athletic injuries. am j sports med 1997; 25: 130-7. 14. mcnaire pj, stanley sn, struass gr. knee bracing: effects on proprioception. arch phys med rehabil 1996; 77: 287-9. 15. millet c, drez d. knee braces. orthopedics 1987; 10: 1777-80. 16. millet c, drez d. principles of bracing for the anterior cruciate ligaments deficient knee. clin sports med 1988; 7: 827-33. 17. paulos le, france ep, rosenburg td. the biomechanics of lateral knee bracing. part i: response of the valgus restraints to loading. am j sports med 1987; 15: 419-29. 18. perlua r, frank c, fick g. the effect of elastic bandages on human knee proprioception in the uninjured population. am j sports med 1995; 23: 251-5. 19. powell j. patterns of knee injuries associated with college football. journal of athletic training summer 1985; 9: 104-9. 20. pritchett j. a statistical study of knee injuries due to football in high school athletes. j joint bone surg am 1982; 64a: 240-2. 21. sforzo ga, chen nm, gold ca, frye pa. the effect of prophylactic knee bracing on performance. med sci sports exerc 1989; 21: 254-7. 22. swash m. position sense in a damaged knee. j neurol neurosurg psychiatry 1986; 49: 100-1. 23. wojtys e m, kothari su, huston lj. anterior cruciate ligament functional brace use in sports. am j sports med 1996; 24: 539-46. 36 sports medicine vol 16 no.1 2004 table ii. average unbalanced times recorded in seconds on the wilknox quad time logger for playing rugby union players (braced vs non-braced) non% significant groups braced (sd) braced (sd) difference difference combined 16.530 (9.9) 20.137 (10.3) 18 p < 0.01 (n = 30) backs 15.580 (10.0) 18.720 (10.0) 17 p < 0.01 (n = 20) forwards 18.430 (9.4) 22.970 (10.2) 20 p < 0.05 (n = 10) table iii. peak unbalanced times recorded in seconds on the wilknox quad time logger for playing rugby union players (braced vs non-braced) non% significant groups braced (sd) braced (sd) difference difference combined 14.449 (9.2) 17.850 (9.5) 19 p < 0.01 (n = 30) backs 11.700 (9.2) 15.070 (9.5) 22 p < 0.01 (n = 20) forwards 17.060 (9.3) 21.160 (9.2) 19 p < 0.05 (n = 10) introduction c-reactive protein (crp) was first discovered in 1930 by william tillet and thomas francis. 48 in studying the blood of patients suffering from acute streptococcus pneumonia infection, it was found that the sera of these patients formed a precipitin with an extract from the streptococcal bacterium. the extract was originally labelled fraction c, and was later confirmed as a polysaccharide. hence, as a result of its reactivity with the c-polysaccharide of the streptococcus cell wall, the ‘substance’ in the sera was named crp. crp ligand-binding is calcium dependent and binds with highest affinity to phosphocholine (pc), a constituent of the cell membrane phospholipid, phosphatidylcholine. under normal conditions phophatidylcholine is not exposed, however, once a cell has been damaged it becomes ‘accessible’ to crp. 7,52 synthesis and application crp synthesis was originally thought to be confined to the liver with no evidence supporting its production in cells other than hepatocytes. 35 jabs et al. 15 have recently shown by real-time polymerase chain reaction (pcr) and immunohistochemistry, that in response to stimulation with interleukin6 (il-6), renal cortical tubular epithelial cells express crp messenger ribonucleic acid (mrna). additional extrahepatic sites of crp synthesis/gene expression have been identified and include the epithelial cells of the human respiratory tract and t-lymphocytes in culture. 13,14 it is still generally accepted that the liver is the primary site of de novo crp production. crp concentration can increase dramatically up to 1 000fold during the acute-phase response, and usually peaks 24 48 hours after an initial acute inflammatory stimulus. 20,34 the half-life of crp is 19 hours and is independent of the circulating concentration of crp. 1 hence, the primary factor determining the serum level of crp is the rate at which it is produced. 1 normal systemic crp levels are classified as less than 5 mg/l with averages of the sedentary/general population being estimated at approximately 2 mg/l. 9 no difference in concentration exists between males and females, nor does crp exhibit diurnal or seasonal variation. 6,34 serum levels are not affected by food intake, however, ganapathi et al. 10 have shown that the crp levels in human hepatoma cell lines are potentiated by caffeine. in addition, church et al. 5 have shown that crp levels are reduced through the use of a multivitamin over a 6-month period. regardless of the nature and location of cellular/tissue damage, a non-specific, systemic acute-phase response is initiated. although crp has been identified as one of the most prominent acute-phase proteins that allows for quantification review article c-reactive protein — biological functions, cardiovascular disease and physical exercise s j semple (dtech) department of sport and physical rehabilitation sciences, tshwane university of technology, pretoria abstract c-reactive protein (crp) is an acute-phase reactant that increases in response to noxious stimuli that inevitably induce cellular and/or tissue injury. the increased synthesis of crp occurs predominantly in the liver and peaks 24 48 hours after the inciting stimulus. crp forms an integral component of innate immunity and serves primarily to recognise potential pathogens and damaged cells. it facilitates the removal of these cells through opsonisation and activates the complement system. with increasing evidence supporting the classification of artherosclerosis as inflammatory in nature, crp has received considerable attention as a marker, and in some cases a contributor towards this cardiovascular disease. traditionally, crp has been measured within exercise studies to provide evidence that an acute-phase inflammatory response can or has been initiated. although the elevation in crp following exercise has largely been attributed to muscle damage, evidence is mounting to contest this premise. participation in chronic exercise has been associated with a reduced risk of cardiovascular disease. numerous studies have now shown an inverse relationship between physical activity levels and resting concentrations of crp. thus, exercise may prove beneficial in lowering systemic inflammatory markers such as crp, and consequently contribute towards preventing the progression of inflammatory disorders. correspondence: s j semple department of sport and physical rehabilitation sciences tshwane university of technology private bag x680 pretoria 0001 tel: 012-318 4324 fax: 012-318 5801 e-mail: semplesj@tut.ac.za 24 sajsm vol 18 no. 1 2006 c-reactive protein.indd 24 3/13/06 12:48:55 pm of an inflammatory state, its elevation cannot differentiate between damaged tissues, hence its measurement and diagnostic value has been questioned. 1 thus, crp is generally measured within a clinical setting to provide the physician with an indication of disease activity, the effectiveness of pharmacological treatment and to determine if intercurrent infections have manifested. 1 whilst an increase in crp has generally been accepted as a response to an inflammatory ‘condition’, kushner has proposed that minor elevations of crp are indicative of biological ageing, a non-inflammatory condition. 19 biological properties and functions of crp recognition of pathogens and damaged cells as part of the acute-phase response, crp levels may rise dramatically in order to facilitate non-specific immune functions and assist with the repair process. the ability of crp to recognise disease-causing agents and damaged cells, and to mediate their removal, in conjunction with the fact that there exists an absence of any documented human crp deficiency, highlights its crucial role in innate immunity. within the human body millions of cells die each day. gershov et al. 11 have proposed that a key role of crp is to facilitate the removal of these cells. they reported that in addition to binding to lysed or permeabilised cells, crp binds to the membranes of intact apoptotic cells. the increased crp was associated with enhanced phagocytosis of the apoptotic cells and would thus contribute towards their clearance. opsonisation on binding to various cell membrane surfaces or necrotic tissue/debris, crp then acts as an opsonin (from the greek meaning ‘prepare food for’). 2 opsonisation involves coating of the bacterial surface so that it can be recognised by other cells of the immune system, specifically macrophages and neutrophils. thus, opsonisation by crp promotes the uptake, and therefore removal of these cells by phagocytes. activation and regulation of complement pathways (pro v. anti-inflammatory role) in addition to the binding and subsequent opsonisation of pathogens, crp also serves to activate and modulate complement. crp binds to c1q, the first component of the complement cascade, and thereby initiates activation of the classical pathway. the activation of complement serves to enhance opsonisation and increase local inflammation. berman et al. 3 have shown that although crp activates the classical pathway of complement, the terminal components (c5c9) known as the membrane attack complex (mac) are not activated. this was in contrast to immunoglobulin g (igg) and immunoglobulin m (igm) activation of the classical pathway, which formed the mac. the non-activation of the mac could be interpreted as an anti-inflammatory mechanism, since activation of these terminal components has been associated with cellular injury and the release of pro-inflammatory cytokines. crp also inhibits the alternate and lectin pathways of complement through the recruitment of factor h, a regulatory protein that promotes the degradation of the c3 and c5 convertase. 27 thus crp plays a dual pro and anti-inflammatory role in its regulation of the complement system. the immunomodulating actions of crp and its pro and anti-inflammatory effects are not restricted to complement. pue 37 has shown that in response to lipopolysaccharide (lps), the hosts’ peripheral blood mononuclear cells (pbmc) respond to crp in a pro-inflammatory manner. however, once the crp has moved into the tissue and reacts with macrophages, inflammation is suppressed through the inhibition of interleukin-1b (il-1b) and interleukin-1ra (il1ra). additional anti-inflammatory properties exhibited by crp include the ability to decrease the expression of cell adhesion molecule (l-selectin) in vitro, and reduce neutrophil superoxide production. 9,54 crp and cardiovascular disease a plethora of studies have recently associated elevated serum crp levels with an increased risk of developing cardiovascular disease (cvd). the increase in crp is indicative of an inflammatory response, and it is now widely accepted that atherosclerosis (the underlying cause of most cvd) is a chronic inflammatory disorder. 38 atherosclerosis is in part characterised by the deposition and accumulation of lipids within arterial walls. these lesions can lead to ischaemia of the brain, heart and peripheral tissues resulting in infarction. 38 the oxidation of low-density lipoprotein (ldl) deposited on arterial walls is one of a number of factors contributing to what has been termed endothelial dysfunction, 38 a hypothesis proposing that vascular injury, and hence inflammation, is induced by a number of factors and possibly a combination thereof. possible causes of endothelial dysfunction are elevated and modified ldl, diabetes, genetic alterations, cigarette smoking, hypertension, elevated homocysteine, and infectious microorganisms (e.g. chlamydia pneumoniae). 38 although substantial evidence from numerous studies has identified crp as a marker of cvd, increasing evidence is now implicating crp as a risk factor directly involved in atherogenesis. cermak et al. 4 have reported that crp induced a 75-fold increase in tissue factor (tf) procoagulant activity of pbmc. it was suggested by the authors that the increase in monocyte tf expression (during infection/ necrosis) induced by crp could contribute towards the development of intravascular coagulation. this could arguably exacerbate the inflammatory state already present in ‘injured’ vessels. nakagomi et al. 29 also reported increases in pbmc tf concentrations in response to stimulation with crp. the authors proposed that their findings shed light on the link between inflammation and coagulation, a connection ‘which may contribute to the progression and outcome of sajsm vol 18 no. 1 2006 25 c-reactive protein.indd 25 3/13/06 12:48:56 pm thrombotic events associated with atherosclerosis’. using human umbilical vein endothelial cells, pasceri et al. 31 showed that crp induced the expression of monocyte chemoattractant protein-1 (mcp-1), a chemokine that attracts monocytes, natural killer (nk) cells and activates macrophages. the same group reported a crp-induced increase in the expression of intercellular adhesion molecule1 (icam-1) and vascular cell adhesion molecule-1 (vcam-1) in umbilical vein as well as coronary artery endothelial cells. 32 inhibiting the expression of cellular adhesion molecules has been shown to decrease phagocytic activity within atherosclerotic plaque. 33 pasceri et al. 32 concluded that crp is not just a marker of inflammation, but rather that it may contribute to enhancing the progression of inflammation/ atherosclerosis. in keeping with the role that crp plays in contributing towards atherogenesis, zwaka et al. 55 demonstrated that crp facilitates the phagocytosis of native ldl by macrophages. the uptake of ldl particles by macrophages results in the formation of lipid peroxides, promotes the accumulation of cholesterol esters and eventually forms foam cells. 38 zwaka et al. 55 suggested that the binding of crp to ldl within arterial walls might promote the onset of arteriosclerosis. nitric oxide (no) plays an integral role in inflammation and immune regulation with lowered levels associated with adverse cardiac events. verma et al. 51 incubated endothelial cells with a concentration of recombinant crp known to predict adverse cardiovascular events. they measured the production of no and cyclic guanosine monophosphate (cgmp), the second messenger for no. crp elicited a dose-dependent, significant decrease in both no and cgmp production. the authors concluded that the inhibitory effect that crp exerts on no production may facilitate the development of cardiovascular disease. similarly, venugopal et al. 50 investigated the effects that crp had on endothelial nitric oxide synthase (enos) expression. human aortic endothelial cells (haec) were incubated with recombinant crp, and in a finding mirroring that of venugopal et al., 50 enos and enos mrna protein levels were inhibited by crp. this finding further supports the role of crp in the artherogenic process. yasojima et al. 53 used a reverse transcriptase-polymerase chain reaction to detect mrna for crp and complement proteins (c1-c9) in arterial and atherosclerotic plaque. they found evidence of crp as well as c1-c9 being synthesised within the arterial tissue of 10 postmortem cases. in addition, mrna and the respective proteins were elevated in atherosclerotic plaque. since complement proteins have been associated with atherosclerotic plaque, 39 and crp is instrumental in potentiating local inflammation by binding with c1q it seems tenable that crp may be involved in the pathogenesis of atherosclerosis. inflammation and exercise it has been proposed that physical activity may serve as a model for studying the inflammatory response, 41 and it is well established that an acute bout of exercise may alter the circulating levels of a number of pro-inflammatory cells including cytokines, acute-phase proteins and white blood cells. 25,40,45 although there is general consensus regarding the induction of an acute-phase inflammatory response following strenuous, unaccustomed or prolonged bouts of exercise, there is some degree of uncertainty surrounding the precise stimuli responsible for this response. the majority of authors have attributed the rise in inflammatory markers following physical activity to muscle damage. evidence suggesting a possible role of other factors/stimuli involved in inducing or exacerbating the inflammatory response following exercise may include haemolysis, 21 endotoxaemia, 16 and the production of reactive oxygen species. 17 in addition, psychological stress, which may be more prevalent in elite athletes, has also been shown to cause an increase in pro-inflammatory cytokines. 22 invariably, the mode, duration and intensity of the exercise, as well as the subject’s level of conditioning may all affect the magnitude of the inflammatory response as well as resting concentrations of inflammatory markers such as crp. in keeping with this, king et al. 18 have proposed that certain activities such as jogging, may be more beneficial in terms of lowering inflammatory markers than other modes of exercise. as outlined above, crp is involved in the activation of the classical pathway of complement. complement proteins are intimately involved in opsonisation, inflammation and cell lysis, 28,42 and have been investigated in response to exercise of varying mode and duration. similar to crp, the specific stimuli that upregulate complement proteins following exercise are controversial. however, as with crp the resting concentrations of selected complement proteins have been shown to be lower in athletes compared with sedentary individuals. 30 more specifically, nieman et al. 30 reported lower levels of c3 in athletes compared with sedentary controls. interestingly, elevated c3 has recently been proposed as a marker to identify the progression of atherosclerosis. 46 effects of acute exercise on crp the acute response of crp to physical activity has been published extensively, and the following section outlines a few of the common findings. increases in crp have been observed following acute strenuous, prolonged bouts of running, 40 triathlon, 16,47 bench stepping 12 and anaerobic exercise. 26 since eccentrically based exercise is more commonly associated with muscle damage, and crp serves to bind damaged cells, it seems reasonable to assume that this type of activity would be associated with pronounced elevations in crp. results contradicting this assumption have been documented by sorichter et al. 44 and malm et al. 23 in both studies no significant elevations were observed for crp following eccentric exercise (70 eccentric quadriceps contractions, and 45 minutes of downhill running respectively). these results suggest that elevations in crp following exercise may not be solely due to muscle damage. supporting this would be the findings of smith et al. 43 in this study, crp was significantly 26 sajsm vol 18 no. 1 2006 c-reactive protein.indd 26 3/13/06 12:48:56 pm (p < 0.04) elevated in 75% of active-untrained subjects, 24 hours after performing 60 minutes of cycling at only 60% of maximal oxygen uptake. similarly, meyer et al. 26 reported a significant (p = 0.02) increase in crp 24 hours after 12 trained males performed an anaerobic cycle ergometer test. effects of chronic exercise on crp pitsavos et al. 36 used a sample of 891 men and 965 women older than 18 years, to determine the association of leisuretime physical activity on crp and other inflammatory markers. the results revealed that crp levels were 33% lower in the subjects who partook in high-physical activity levels compared with the sedentary group (high-physical activity was defined as expended calories > 7 kcal/min). similarly, our laboratory has observed (unpublished data) that crp resting levels are significantly lower in professional cyclists compared with active-untrained individuals. tomaszewski et al. 49 have reported ‘strikingly’ low crp levels in runners. sixty-seven male ultra-marathon runners were compared with sedentary individuals. they were all categorised into groups having a body mass index (bmi) less than 25 kg/m 2 or greater than 25 kg/m 2 . although nonsignificant, the resting levels of crp were markedly lower in the marathon athletes compared with the controls. even though there were differences in bmi, the crp levels were similar amongst the marathon runners. thus, the authors suggested that lowered crp levels can be attained by intense regular exercise, and that this suppression is independent of adiposity levels. an interesting study by mattusch et al. 24 revealed changes in crp concentration following 9 months of training. fourteen males (25 40 years) preparing for the cologne marathon provided blood samples before and after 9 months of training for the event. the mean crp concentration before the training began was 1.19 ± 1.63 mg/l for athletes, and after 9 months was significantly (p < 0.05) reduced to 0.82 ± 0.94 mg/l. there were no significant changes reported for the control group. the authors suggested that an anti-inflammatory effect is induced by endurance exercise performed over 9 months. similarly, fallon et al. 8 reported significantly (p < 0.05) decreased levels of crp following 9 months of soccer training in elite women, from a resting level of 2.68 (± 1.70 mg/l) to 1.62 (± 1.32 mg/l). it was suggested that systemic anti-inflammatory mechanisms, associated with regular intense exercise were behind this finding. the proposed antiinflammatory effect of chronic exercise suggests that physical activity may impart favourable health benefits on individuals by lowering crp, a key role player in cardiovascular disease. in conclusion, crp is an acute-phase protein that is upregulated in response to injury, infection or antigen exposure. crp usually peaks 24 hours after exercise, and is more pronounced following longer more strenuous activity. the elevations in crp following exercise have largely been attributed to muscle damage, however, it seems plausible that muscle damage does not have to be elicited by exercise in order for crp to be elevated. 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12:48:57 pm original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license presenting features of female collegiate sports-related concussion in south africa: a descriptive analysis r van tonder,1,3 mba, msc (sem); l kunorozva,1,3 phd; pl viviers,1,2,3 msc (sem), facsm; ew derman,1,3 phd, facsm; jc brown,1,3 phd, mph 1 institute of sport and exercise medicine, division of orthopaedic surgery, faculty of medicine and health sciences, stellenbosch university, stellenbosch, south africa 2campus health service, stellenbosch university, stellenbosch, south africa 3ioc research centre, south africa corresponding author: r van tonder (riaanvt@sun.ac.za) sports-related concussion (src) is defined as a traumatic sports-related brain injury induced by biomechanical forces, caused either by a direct blow to the head, face, neck or elsewhere on the body, with an impulsive force transmitted to the head.[1] symptomatology (e.g. somatic, cognitive and/or emotional symptoms, physical signs, balance impairment, behavioural changes, cognitive impairment, and sleep/wake disturbances) generally develops predictably but can vary in number, type, severity and time course, and is not due to any other cause (i.e. drugs, alcohol, medication, etc.).[1] females face a greater src risk, sustain src at an increased rate, have increased time loss, report more symptoms at baseline and in the immediate post-concussion period, and experience greater neurocognitive impairment. in addition, females have a higher risk for post-concussion syndrome, suffer prolonged recovery from src, have an increased risk for depression, and may report a higher number of src-related symptoms one year after an src.[2-4] thus, the symptom burden of src in female collegiate athletes appears to be high. furthermore, wilmoth et al.[5] suggest that student athletes experience several psychological challenges. these challenges may include emotional and social functioning, behavioural problems, academic difficulties, sleep disturbances, headaches and reduced quality of life following src, given the importance of athletics and related social activities in their lives. students have also been shown to experience increased levels of anxiety and depression.[6] evidence regarding src assessment in females is scarce, compared to src assessment in males. more data are needed, specifically evaluating females independently,[7] to expand the current evidence base and determine whether females with src are presently assessed and managed appropriately.[3] to our knowledge, the association between potential pre-existing risks and src has not been investigated to specific symptom type in female collegiate athletes in a culturally diverse developing nation, as the majority of the research in this field has been conducted in developed northern hemisphere settings. therefore, we aimed to describe presenting features of female src at a collegiate campus-based sports medicine service and investigated the association of presenting symptoms with prior concussion history (pconc) or mental health conditions (pmhdx). methods a retrospective cohort analysis of female collegiate student athletes with src presenting to a campus-based sports medicine service between the years of 2012 and 2018 was performed. the stellenbosch university health research ethics committee granted ethical approval for this study (hrec ref no. n17/08/068). electronic medical records were examined for icd-10 concussion codes (s06.0, s06.00 and s06.01). only female records were included and analysed for study inclusion eligibility, i.e. concussion cause was classified as sports-related or non-sports-related. only srcs were included in this study. the relevant clinical assessment data were extracted from this data subset. the campus-based sports medicine service is the primary medical care provider for students at the university, which is situated centrally in this university town and therefore highly background: sports-related concussion (src) is an injury with important implications, especially in collision and contact sports, and has a high symptom burden. student athletes face particular psychosocial challenges, especially female students with pre-existing anxiety/depression are at increased risk for src, and have a higher symptom burden before and after injury. objectives: describing female src presenting features at a collegiate campus-based sports medicine service; examining the association of prior concussion history (pconc) and preexisting anxiety/depression (pmhdx) with src. methods: a retrospective cohort and statistical analysis (including corrected effect sizes) of sport concussion assessment tool (versions 3/5) data (step 1: pconc and pmhdx history; step 2: symptom evaluation) of collegiate female athletes with src between 2012 and 2018. results: forty females with src were identified (age 23 ± 3). the five most frequent symptoms were headache (n = 34; 85%), feeling slowed down (n = 33; 83%), pressure in head (n = 33; 83%), don't feel right (n = 32; 80%) and fatigue/low-energy (n = 32; 80%). these five symptoms also had the highest self-rated severity (median (iqr): headache (3 (2-4)), feeling slowed down (3 (1-4)), fatigue/low-energy (3 (1-5)), don't feel right (3 (1-4)) and pressure in head (3 (2-4)). pmhdx (n = 8; 62.9 vs 38.6; p = 0.0192; hedges' gs = 0.95; large es), and not pconc (n = 13; 51.0 vs 39.8; p = 0.2183; hedges' gs = 0.48; small es) was associated with increased mean total symptom severity. conclusion: headache, feeling slowed down, pressure in head, don't feel right and fatigue/low-energy had the highest symptom burden. total symptom severity was no different in those with and without pconc, but significantly higher in those with pmhdx. keywords: src, depression, anxiety, athlete, outcome s afr j sports med 2021;33:1-7. doi: 10.17159/2078-516x/2021/v33i1a10416 mailto:riaanvt@sun.ac.za http://dx.doi.org/10.17159/2078-516x/2021/v33i1a10416 https://orcid.org/0000-0002-7778-7783 https://orcid.org/0000-0002-8879-177x https://orcid.org/0000-0003-2858-0863 https://orcid.org/0000-0001-6682-3438 http://orcid.org/0000-0003-4262-6696 original research sajsm vol. 33 no. 1 2021 2 accessible. the university subsidises all costs of services rendered by this sports medicine service to athletes of the university's high performance programme. in contrast, nonhigh performance athletes included in this study were required to cover the cost of services rendered by doctors, either personally or through private medical insurance. the medical service fees were structured to allow for maximum provision of services to students and not to act as a barrier to its use. furthermore, students could consult, free of charge, with primary nurse practitioners. all srcs were diagnosed by an experienced, consistent group of sports physicians at a specialised sports medicine service based on the most recent consensus clinical definitions and guidelines for concussion diagnosis. the src assessment included the use of scat (versions 3/5, using the currently available version at the time of assessment) questionnaires for all suspected or confirmed concussion cases at initial presentation and subsequent follow-up visits. pconc and pmhdx data were collected in the scat step 1. the scat step 2 documents the self-reported severity of 22 symptoms based on a 7-point likert scale of 0–6 (0 = symptom absent, 6 = highest symptom severity), with a maximum possible total severity score of 132 (6 x 22). total symptom number and severity were also recorded. the following three outcomes were described and compared between the relevant groups i.e. (1) those with and without pconc, and (2) those with and without pmhdx: (1) reported severity (0-6) of each of the 22 specific symptoms (e.g. headache, nausea/vomiting, etc.); (2) overall number of reported symptoms (0-22); and (3) overall severity of all reported symptoms (0-132). descriptive statistical analyses were performed on all relevant reported data from scat steps 1 and 2. shapirowilks tests analysed normality, followed by null hypothesis testing (mann-whitney u test for non-normal data; parametric unpaired t test for normally distributed data). in the absence of normative reference tables for scat test scores, clinically relevant findings for betweengroup comparisons of the three stated outcomes were determined with the combination of: (1) large (≥0.8) corrected effect size (es) and (2) appropriate (parametric or non-parametric, depending on data distribution) null hypothesis testing, with a null hypothesis rejected for p < 0.05. symptom severity was determined by calculating the mean of all individually reported scores for a specific symptom. symptom burden was determined as a product of symptom severity and symptom frequency. the two sets of groups that were compared for clinically relevant differences were: 1) between those with and without pconc and 2) those with and without pmhdx. statistical comparisons were performed with a combination of microsoft® excel for mac (version 16.37, microsoft® corporation) and graphpad prism (version 8, graphpad software llc), and verified in stata (statacorp. 2011. stata statistical software: release 12. college station, tx: statacorp lp). results forty (27% of n = 146) female collegiate athletes with src were identified, with a mean age of 23 years (sd ± 3). the included src cases were unique, i.e. all patients only had one initial scat evaluation. forty-three records were related to organised sports participation and 103 records were related to recreational, non-sports-related incidents. three sports-related records had no scat data and were therefore excluded from the analysis. three records related to cycle commuting and one record related to recreational, leisure-time ice skating were deemed to be ‘non-organised’ sports-related causes of concussion for the purpose of this study and excluded from further analysis.[8] each record noted possible pconc and pmhdx data. thirty records (75%) contained data from scat3 (2012-2017), and 10 records (25%) contained data from scat5 (2017 onwards). field hockey (n = 21; 53%) and rugby union (n = 8; 20%) accounted for the highest and second highest number of srcs, respectively. other sports involved included cycling (n = 2; 5%), soccer (n = 2; 5%), surfing (n = 2; 5%), netball (n = 2; 5%), water polo (n = 2; 5%), basketball (n = 1; 3%), horse riding (n = 1; 3%), gymnastics (n = 1; 3%) and dancing (n = 1; 3%). the presenting symptoms are shown in table 1. overall, the five most frequent symptoms were headache (n = 34; 85%), feeling slowed down (n = 33; 83%), pressure in head (n = 33; table 1. overall (n = 40) mean symptom severity and symptom frequency n (%) mean ± sd median (iqr) number of symptoms 13.3 ± 5.6 13 (10-17) symptom severity score 43.5 ± 26.7 42.5 (26-62) headache 34 (85) 3.0 ± 1.7 3 (2-4) pressure in head 33 (83) 2.8 ± 1.8 3 (2-4) neck pain 27 (68) 2.1 ± 1.9 2 (0-4) nausea/vomiting 21 (53) 1.7 ± 1.9 1 (0-3) dizziness 31 (78) 1.9 ± 1.5 2 (1-3) blurred vision 15 (38) 0.9 ± 1.4 0 (0-1) balance problems 16 (40) 1.1 ± 1.6 0 (0-2) sensitivity to light 23 (58) 1.6 ± 1.7 1 (0-3) sensitivity to noise 19 (48) 1.5 ± 1.9 0 (0-3) feeling slowed down 33 (83) 2.9 ± 1.9 3 (1-4) feeling like in a fog 27 (68) 2.4 ± 2.0 3 (0-4) don’t feel right 32 (80) 2.8 ± 1.9 3 (1-4) difficult concentrating 28 (70) 2.5 ± 2.2 2 (0-4) difficulty remembering 24 (60) 1.8 ± 1.8 2 (0-3) fatigue/low energy 32 (80) 2.9 ± 2.2 3 (1-5) confusion 19 (48) 1.5 ± 1.9 0 (0-2) drowsiness 28 (70) 2.4 ± 2.0 2 (0-4) trouble falling asleep 18 (45) 1.8 ± 2.2 0 (0-3) more emotional 20 (50) 1.8 ± 2.1 1 (0-4) irritability 19 (48) 1.8 ± 2.1 0 (0-4) sadness 17 (43) 1.3 ± 1.8 0 (0-2) nervous/anxious 17 (43) 1.2 ± 1.7 0 (0-2) n, absolute frequency of symptoms; %, percentage of symptom frequency; sd, standard deviation; iqr, interquartile range original research 3 sajsm vol. 33 no. 1 2021 83%), don't feel right (n = 32; 80%) and fatigue/low energy (n = 32; 80%). the five most severe symptoms were: headache (median (iqr); 3 (2-4)), feeling slowed down (median (iqr); 3 (1-4)), fatigue/low energy (median (iqr); 3 (1-5)), don't feel right (median (iqr); 3 (1-4)) and pressure in head (median (iqr); 3 (2-4)). these five symptoms therefore had the highest symptom burden (frequency x severity). the median total symptom number and severity was 13 (iqr 10-17) and 42.5 (iqr 26-62), respectively. table 2 summarises data comparing individuals with (n = 8) and without (n = 32) pmhdx. pmhdx was not associated with a higher mean symptom number (15.6 ± 5 vs 12.7 ± 5.7; p = 0.197; moderate es) but was associated with a significantly higher mean total symptom severity (62.9 ± 9.7 vs 38.6 ± 24.5; p = 0.019; table 2. no prior mental health diagnosis vs prior mental health diagnosis (pmhdx) symptom severity and symptom frequency no pmhdx (n = 32) pmhdx (n = 8) n (%) mean ± sd median (iqr) n (%) mean ± sd median (iqr) mδ mδ % ds gs es u t number of symptoms 12.7 ± 5.7 13 (10-17) 15.6 ± 5.0 16 (9-20) 2.9 22.9 0.52 0.51 ** 0.197^ symptom severity score 38.6 ± 24.5 37 (21-58) 62.9 ± 27.5 65 (29-86) 24.3 62.9 0.97 0.95 *** 0.019^ headache 26 (81) 2.7 ± 1.7 3 (2-4) 8 (100) 4.1 ± 0.8 4 (3-5) 1.5 55.3 0.92 0.91 *** 0.019^ pressure in head 25 (78) 2.6 ± 1.8 3 (2-4) 8 (100) 3.4 ± 1.6 3 (1-4) 0.8 28.6 0.43 0.42 * 0.354 neck pain 23 (72) 2.1 ± 1.8 2 (0-4) 4 (50) 1.9 ± 2.2 1 (0-4) -0.3 -11.8 -0.13 -0.13 * 0.689 nausea/ vomiting 14 (44) 1.2 ± 1.7 0 (0-2) 7 (88) 3.4 ± 1.9 4 (0-4) 2.2 176.9 1.25 1.22 *** 0.005^ dizziness 24 (75) 1.7 ± 1.4 2 (1-3) 7 (88) 2.8 ± 1.7 3 (0-4) 1 60 0.7 0.69 ** 0.113 blurred vision 10 (31) 0.6 ± 1.1 0 (0-1) 5 (63) 2.0 ± 2.0 2 (0-3) 1.4 255.6 1.11 1.09 *** 0.036^ balance problems 12 (38) 0.9 ± 1.4 0 (0-2) 4 (50) 1.9 ± 2.3 1 (0-3) 0.9 100.4 0.58 0.57 ** 0.309 sensitivity to light 17 (53) 1.2 ± 1.4 1 (0-2) 6 (75) 2.9 ± 2.2 3 (0-4) 1.7 135.9 1.04 1.02 *** 0.046^ sensitivity to noise 13 (41) 1.2 ± 1.7 0 (0-2) 6 (75) 2.9 ± 2.2 3 (0-4) 1.7 148.6 0.95 0.94 *** 0.031^ feeling slowed down 25 (78) 2.7 ± 1.9 3 (1-4) 8 (100) 4.0 ± 1.1 4 (3-4) 1.3 50.6 0.75 0.73 ** 0.1 feeling like in a fog 21 (66) 2.2 ± 1.9 3 (0-4) 6 (75) 3.0 ± 2.5 4 (0-5) 0.8 35.2 0.39 0.38 * 0.37 don’t feel right 24 (75) 2.5 ± 1.9 3 (1-4) 8 (100) 3.9 ± 1.6 4 (1-5) 1.3 53.1 0.72 0.71 ** 0.075 difficulty concentrating 21 (66) 2.3 ± 2.2 2 (0-4) 7 (88) 3.3 ± 1.9 4 (0-4) 1 44.4 0.47 0.46 * 0.231 difficulty remembering 18 (56) 1.6 ± 1.7 2 (0-3) 6 (75) 2.6 ± 2.0 3 (0-4) 1 64.7 0.58 0.57 ** 0.17 fatigue/low energy 26 (81) 2.7 ± 2.1 3 (1-4) 6 (75) 3.5 ± 2.3 4 (0-5) 0.8 28.7 0.36 0.35 * 0.411 confusion 14 (44) 1.2 ± 1.7 0 (0-2) 5 (63) 2.6 ± 2.5 3 (0-4) 1.5 127 0.8 0.78 ** 0.113 drowsiness 22 (69) 2.1 ± 1.9 2 (0-3) 6 (75) 3.6 ± 2.3 5 (0-5) 1.5 73.1 0.78 0.77 ** 0.059 trouble falling asleep 15 (47) 1.7 ± 2.1 0 (0-3) 3 (38) 1.9 ± 2.8 0 (0-4) 0.2 9.1 0.07 0.07 * 0.989 more emotional 16 (50) 1.6 ± 2.0 1 (0-4) 4 (50) 2.4 ± 2.6 2 (0-4) 0.8 46.2 0.36 0.35 * 0.506 irritability 15 (47) 1.6 ± 1.9 0 (0-3) 4 (50) 2.5 ± 2.7 2 (0-5) 0.9 60 0.45 0.44 * 0.357 sadness 14 (44) 1.2 ± 1.5 0 (0-2) 3 (38) 1.9 ± 2.6 0 (0-4) 0.7 57.9 0.38 0.38 * 0.708 nervous/anxious 13 (41) 1.00 ± 1.4 0 (0-2) 4 (50) 2.1 ± 2.5 2 (0-4) 1.1 112.5 0.68 0.66 ** 0.286 n, absolute frequency of symptoms; %, percentage of symptom frequency; sd, standard deviation; iqr, interquartile range; mδ, mean difference; mδ %, mean difference percentage; ds, cohen's ds; gs, hedges' gs; es, effect size; u, mann whitney u test; t, unpaired t test; ^,p < 0.05; *, small es; **, moderate es; ***, large es. original research sajsm vol. 33 no. 1 2021 4 large es). headache (p = 0.019; large es), nausea/vomiting (p = 0.005; large es), blurred vision (p = 0.036; large es), sensitivity to light (p = 0.046; large es), and sensitivity to noise (p = 0.031; large es) were significantly more severe in those with pmhdx, while the remaining symptoms showed no differences between groups. when comparing individuals with (n = 13; 32.5%) and without (n = 27; 67.5%) pconc, we found no differences in individual mean symptom severity, total mean symptom severity or total symptom frequency between groups. table 3 presents a summary of these data. discussion the first important finding of this study was that the symptoms most frequently reported overall were headache, feeling slowed down, fatigue/low energy, don't feel right, and pressure in head which is consistent with findings in other similar populations.[2-4, 9, 10] the highest mean symptom severity scores were reported for headache, feeling slowed down and fatigue/low energy, don't feel right, and pressure in head. combined, this suggests that these five symptoms carry the table 3. no prior concussion vs prior concussion (pconc) symptom severity and symptom frequency no pconc (n = 27) pconc (n = 13) n (%) mean ± sd median (iqr) n (%) mean ± sd median (iqr) mδ mδ % ds gs es u t number of symptoms 12.7 ± 6.1 13 (10-17) 14.5 ± 4.6 15 (11-18) 1.7 13.5 0.3 0.30 * 0,373 symptom severity score 39.8 ± 25.6 37 (25-60) 51.0 ± 28.4 46 (32-81) 11.2 28.1 0.49 0.48 * 0,218 headache 21 (78) 2.7 ± 1.8 3 (2-4) 8 (100) 3.5 ± 1.2 4 (3-4) 0.9 32.7 0.53 0.52 ** 0,146 pressure in head 21 (78) 2.6 ± 1.7 3 (2-4) 8 (92) 3.2 ± 1.8 3 (2-5) 0.6 21.6 0.32 0.31 * 0,370 neck pain 19 (70) 2.0 ± 1.9 1 (0-3) 4 (62) 2.3 ± 2.0 3 (0-4) 0.3 17.6 0.18 0.18 * 0,655 nausea/vomiting 13 (48) 1.4 ± 1.8 0 (0-2) 7 (62) 2.2 ± 2.2 2 (0-4) 0.7 53 0.39 0.38 * 0,315 dizziness 20 (74) 1.6 ± 1.4 1 (1-3) 7 (85) 2.6 ± 1.6 3 (2-4) 1 64.2 0.71 0.69 ** 0,055 blurred vision 10 (37) 0.7 ± 1.1 0 (0-1) 5 (38) 1.2 ± 1.8 0 (0-3) 0.6 84.6 0.4 0.4 * 0,603 balance problems 9 (33) 0.8 ± 1.3 0 (0-1) 4 (54) 1.8 ± 2.1 1 (0-3) 1 127.5 0.63 0.61 ** 0,134 sensitivity to light 14 (52) 1.2 ± 1.4 1 (0-2) 6 (69) 2.4 ± 2.1 3 (0-4) 1.2 107.7 0.76 0.75 ** 0,071 sensitivity to noise 11 (41) 1.2 ± 1.8 0 (0-3) 6 (62) 2.1 ± 2.1 2 (0-4) 0.9 69.9 0.45 0.44 * 0,160 feeling slowed down 22 (81) 2.8 ± 1.9 3 (1-4) 8 (85) 3.2 ± 1.9 3 (3-4) 0.3 12 0.18 0.18 * 0,630 feeling like in a fog 19 (70) 2.4 ± 1.9 3 (0-4) 6 (62) 2.3 ± 2.4 1 (0-4) -0.1 -4.1 -0.05 -0.05 * 0,926 don’t feel right 20 (74) 2.6 ± 2.0 3 (1-4) 8 (92) 3.2 ± 1.8 4 (2-4) 0.5 19.9 0.27 0.27 * 0,406 difficult concentrating 17 (63) 2.2 ± 2.2 2 (0-4) 7 (85) 2.9 ± 2.0 3 (2-4) 0.7 31.5 0.33 0.32 * 0,312 difficulty remembering 15 (56) 1.6 ± 1.7 1 (0-3) 6 (69) 2.2 ± 2.0 2 (0-3) 0.6 40.1 0.35 0.35 * 0,345 fatigue/low energy 22 (81) 2.9 ± 2.1 3 (1-5) 6 (77) 2.9 ± 2.4 4 (1-5) 0 -1.5 -0.02 -0.02 * 1,000 confusion 13 (48) 1.3 ± 1.6 0 (0-2) 5 (46) 1.9 ± 2.5 0 (0-4) 0.6 46.6 0.31 0.30 * 0,681 drowsiness 19 (70) 2.3 ± 1.9 2 (0-4) 6 (69) 2.7 ± 2.3 4 (0-4) 0.4 19.2 0.21 0.21 * 0,539 trouble falling asleep 13 (48) 1.9 ± 2.3 0 (0-4) 3 (38) 1.4 ± 2.0 0 (0-3) -0.5 -28.1 -0.25 -0.24 * 0,419 more emotional 13 (48) 1.7 ± 2.1 0 (0-4) 4 (54) 2.0 ± 2.2 1 (0-4) 0.3 20 0.16 0.16 * 0,708 irritability 11 (41) 1.5 ± 2.1 0 (0-3) 4 (62) 2.2 ± 2.1 2 (0-4) 0.7 46.9 0.34 0.33 * 0,231 sadness 12 (44) 1.3 ± 1.7 0 (0-2) 3 (38) 1.4 ± 2.1 0 (0-3) 0.1 6.8 0.05 0.05 * 0,954 nervous/anxious 11 (41) 1.2 ± 1.7 0 (0-2) 4 (46) 1.4 ± 1.8 0 (0-3) 0.2 20.6 0.14 0.13 * 0,678 n, absolute frequency of symptoms; %, percentage of symptom frequency; sd, standard deviation; iqr, interquartile range; mδ, mean difference; mδ %, mean difference percentage; ds, cohen's ds; gs, hedges' gs; es, effect size; u, mann whitney u test; t, unpaired t test; *, small es; **, moderate es; ***, large es. original research 5 sajsm vol. 33 no. 1 2021 highest symptom burden in this collegiate female cohort. this finding is consistent with results found in previous research, indicating that females report more somatic symptoms, cognitive difficulties, emotional changes and disordered sleep compared with males.[3] furthermore, the results from our study supports previous research in collegiate athletes which reported that headache, pressure in head and feeling slowed down were more prevalent in female athletes.[2] a recent study by vedung et al.[4] in 51 elite swedish soccer teams during the 2017 season, including 959 elite soccer players (n = 389 females; mean age 23), reported 17 female srcs and the most frequent post-src symptoms were headache, pressure in head, don't feel right and fatigue/low energy, which are consistent with this study. a subgroup of female semiprofessional athletes (aged 23 ± 4; n = 8) in their cohort reported median total symptom severity scores (38.5; iqr 17.75-50.75 vs 42.5; iqr 26-62) and median number of symptoms (14.5; iqr 8.25-18 vs 13; iqr 10-17) assessed at 48 hours post-src that are also consistent with findings in our study’s cohort. it is important to note that our cohort involved 11 different sports, of which field hockey and rugby union alone accounted for 29 srcs; in contrast to the vedung study[4] which focussed solely on soccer players. this consistency of findings between various research settings, from different geographical areas, various sports, and profoundly different local socio-economic environments,[2-4, 9, 10] suggests that these findings are not unique to our setting and study cohort. furthermore, south africa is arguably amongst the most unequal nations globally.[11] secondly, we found that female collegiate athletes with pmhdx reported significantly higher mean total symptom severity, in addition to a significantly higher severity for physical symptoms such as headache, nausea/vomiting, blurred vision, sensitivity to light and sensitivity to noise, than those athletes without pmhdx. this finding supports previous research findings in similar cohorts of female collegiate athletes.[3, 12, 13] indeed, lariviere et al.[13] analysed the electronic records of 4 865 participants, grouped into six age groups (<12 to >40), of whom 1 577 participants selfidentified with a diagnosis of anxiety (n = 171 females; aged 16-29 years), depression (n = 119 females; aged 16-29 years), a behavioural disorder, or a learning disability, and reported that pre-existing anxiety or depression worsened src symptom numbers and severity. this was in addition to females reporting concussion symptoms with increasing frequency and severity across a large range of age groups, significantly so from the age of 20 years upwards. however, there was no difference in the total symptom number reported between these two groups in our study. female sex, previous concussion, and depression were found to be concussion risk factors in a study spanning a period of three years. this study was conducted in a cohort of 10 000 us services academy members (n = 301 concussed females) by van pelt et al.[12] the study also reported that females had twice the risk of concussion independent of injury setting, an increased relative risk for src, and that the female sex, previous concussion, chronic headache, depression and baseline scat scores are significant risk factors for concussion. this study is part of a larger joint effort by the us department of defense and national collegiate athletic association that funds the concussion, assessment, research and education (care) consortium, a multi-site investigation into the natural history of concussion. cadets at the united states service academies are unlike active-duty service members in that there is a larger female population, they have different social, economic, and education characteristics than enlisted service members, and their academy military training activities do not include exposure to combat. cadets are also required to participate in a sport. therefore, one could view the service academies as ‘military universities’. a review by resch et al.[3] found strong predictive value for prior concussion history, female sex, premorbid psychiatric history and anxiety at follow-up, for post-concussion symptoms one week after sustaining a concussion, in addition to anxiety being predictive of continued symptoms at three months post-concussion. these findings by resch et al., who reviewed study cohorts, including male and female high school and collegiate athletes, are consistent with findings of a study in a large cohort of > 9 000 youth soccer players by brooks et al.,[14] which suggested an association between reported postsrc symptom severity, female sex and prior mental health problems but not with prior concussion history. while the cohort in the study by brooks et al. consisted of youth athletes, the findings in our study of a female collegiate-level athlete cohort supports the findings by brooks et al. an additional consideration to be mindful of, as reported in a recent systematic review by trinh et al.[7], is that pre-existing psychological traits, such as irritability, sadness, nervousness and depressive symptoms, are traits which may predispose an individual to depression and/or anxiety, and were associated with a worsened clinical outcome after src. furthermore, as noted in the study by lariviere et al., females consistently report higher symptom severity than do males following concussion. considering that the acute and subacute symptom severity following concussion was shown to be the most consistent predictor of prolonged recovery from concussion,[15] and that individuals with pmhdx were five times more likely to experience prolonged recovery following src,[16] it should become clear that the combination of female sex, pmhdx, and generally higher reported post-concussion symptom severity poses a particularly significant clinical management challenge. therefore, the finding in our study of a significant association between src and pmhdx is consistent with current literature and importantly, adds further weight to the existing evidence base. in contrast to some previous research, we found no association between prior concussion history and the number and severity of reported symptoms in this cohort. many previous studies have concluded that prior concussion history is a risk factor for future concussion. in a 2014 systematic review by abrahams et al.[17], which concluded that prior concussion is a risk factor for future concussion, 10 out of 13 reviewed studies found prior concussion history to be a risk factor; however, 9 of these 10 studies included only male cohorts or were 99% male. the remaining 3 (of 13) studies which found otherwise were of original research sajsm vol. 33 no. 1 2021 6 a low quality. mccrory et al.[1], vedung et al.[4], van pelt et al.[12], and putukian et al.[18] also saw prior concussion history to be a risk factor for subsequent src. while this study did not aim to determine concussion risk factors, it is important to note that most of the evidence suggests that pconc is a risk factor for sustaining a future concussion. in contrast, the evidence regarding clinical outcome following src in those with pconc is equivocal. a comprehensive systematic review of 114 publications by iverson et al.[15] evaluated various possible outcome predictors following src, amongst others sex, pconc, and prior personal and family psychiatric history. it was found that the majority of studies did not show an association between pconc, in contrast to female sex and personal/family psychiatric history, and clinical outcome following src. the conclusion by this author is consistent with the study by brooks. et al. (large cohort of >9 000 youth soccer players) that src outcome is not associated with pconc. our finding supports the absence of an association between pconc and the clinical outcome following src in this small cohort. with overall increasing rates of sports participation among females, increased concussion injury rates, higher total and more severe reporting of symptoms, and increased risk for prolonged, complicated recovery from src among female collegiate athletes, it is imperative that future research continues to expand the body of evidence in this everevolving field of src, as consideration for differences brought about by biological sex carry important implications for the clinical management of src. from the clinician's perspective, these findings bear important clinical relevance. the clinician should be mindful thereof in the management of female collegiate athletes who present for baseline testing or post-injury assessment, in particular those with pmhdx and, although the present cohort showed no association with those with prior concussion history. the data used in this study are based on the information contained in the scat3/5 questionnaires which were completed as a central component in the assessment of suspected cases of src at this collegiate campus-based sports medicine service, the primary difference (in step 2) being that ‘state’ is reported in scat3 compared to ‘trait’ in scat5. during the study period, the scat5 was released following the berlin consensus meeting [1] and although scat3 and scat5 questionnaires are described in this study, asken et al.[19] found adequate convergent validity between scat3 and scat5. the symptomatology data collected in the scat questionnaires rely on the self-reporting of symptoms that is known to introduce bias, as these data cannot be verified independently. the non-parametric nature of these collected scat data, which contain large amounts of zero scores, cause additional statistical constraints. furthermore, it is unclear what the impact of elapsed time is between previous and instant concussions. this requires further study. our statistical measures employed, i.e. the addition of an es measure to differentiate more clearly meaningful clinical findings were strict when compared to previous studies. furthermore, in our study, which could be viewed as both a strength and limitation, all srcs were diagnosed by an experienced consistent group of sports physicians at a specialised sports medicine service in accordance with the most recent consensus clinical definitions and guidelines for concussion diagnosis.[1] this could imply a more narrowly defined cohort of diagnosed concussed athletes, in addition to differences in assessment methods and questionnaires employed elsewhere around the world. recall errors at the time of questionnaire completion may also influence accurate recording of prior concussion history in the athlete who presents with a current concussion. the data analysis derived from this work could be affected by the small sample size, impacting on certain statistical relationships which the cohort in this study did not show but which have been shown to exist in other studies. however, comparative studies also report small female collegiate src cohort sizes.[13,18,20-23] the small sample size is in spite of the multiyear time period under consideration in this study. this should not be construed as an indication of overall low female src incidence. indeed, the src incidence rate was not a focus of this work. rather, it may be possible that the src surveillance and referral systems which exist in women's sports codes on the university’s campus do not lead to an accurate portrayal of the true src incidence. furthermore, local socioeconomic and cultural factors may influence an athlete's awareness and understanding of src and the ability to seek medical care after sustaining an src. therefore, not all src cases may have been recorded. the data analysis was hampered by the fact that three eligible src records had missing scat data. ‘ conclusion this study aims to answer the call for more female specific src research. our findings suggest that the number and severity of symptoms are consistently reported in similar female collegiate athlete cohorts, in addition to similar symptoms being reported in different study cohorts competing in different sports. symptoms with the highest burden were headache, feeling slowed down, pressure in head, don't feel right and fatigue/low energy. we found no difference in the reported number and severity of symptoms between those with and without pconc. however, total and physical symptom cluster severity was significantly higher in those with pmhdx compared to athletes without pmhdx. the finding of a significant association between pmhdx and the src clinical outcome is consistent with previous research. whereas previous research is equivocal regarding an association between pconc and src outcome, the present cohort showed no such association. we encourage further research of female-specific src to expand our knowledge and ultimately improve the health of female athletes. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: rvt was the primary author responsible for conception, design, original research 7 sajsm vol. 33 no. 1 2021 analysis and interpretation of data, with significant contribution from jcb. rvt, lk, plv, ewd, and jcb all contributed w.r.t. critical revision for important intellectual content and approval of the version to be published. references 1. mccrory p, meeuwisse w, dvorak j, et al. consensus statement on concussion in sport – the 5th international conference on concussion in sport held in berlin, october 2016. br j sports med. 2018;51: 838-847. [https://dx.doi.org/10.1136/bjsports2017-097699] 2. covassin t, savage jl, bretzin ac, et al. sex differences in sportrelated concussion long-term outcomes. int j psychophysiol 2018;132(pt a):9-13. [https://dx.doi.org/10.1016/j.ijpsycho. 2017.09.010] [pmid: 28927725] 3. resch je, rach a, walton s, et al.. sport concussion and the female athlete. clin sports med 2017;36(4):717-739. [https://dx.doi.org/10.1016/j.csm.2017.05.002] 4. vedung f, hanni s, tegner y, et al. concussion incidence and recovery in swedish elite soccer prolonged recovery in female players. scand j med sci sports 2020;30(5):947-957. [https://dx.doi.org/10.1111/sms.13644] 5. wilmoth k, tan a, hague c, et al. current state of the literature on psychological and social sequelae of sports-related concussion in school-aged children and adolescents. j exp neurosci 2019;13:1179069519830421. [https://dx.doi.org/ 10.1177/1179069519830421] [pmid: 30814847] 6. aktekin m, karaman t, senol yy, et al. anxiety, depression and stressful life events among medical students: a prospective study in antalya, turkey. med educ 2001;35(1):12-17. [https://dx.doi.org/10.1111/j.1365-2923.2001.00726.x][pmid: 11123589] 7. trinh ln, brown sm, mulcahey mk. the influence of psychological factors on the incidence and severity of sportsrelated concussions: a systematic review. am j sports med 2020;48(6):1516-1525. [https://dx.doi.org/10.1177/0363546519882626][pmid: 1702943] 8. sojka p. “sport” and “non-sport” concussions. cmaj 2011;183(8):887-888. [doi: 10.1503/cmaj.110504] [pmid: 21502346] 9. baker jg, leddy jj, darling sr, et al. gender differences in recovery from sports-related concussion in adolescents. clin pediatr (phila) 2016;55(8):771-775. [https://dx.doi.org/ 10.1177/0009922815606417] [pmid: 26378093] 10. brown da, elsass ja, miller aj, et al. differences in symptom reporting between males and females at baseline and after a sports-related concussion: a systematic review and metaanalysis. sports med 2015;45 (7): 1027-1040. [https://dx.doi.org/10.1007/s40279-015-0335-6][pmid: 25971368] 11. sulla v, zikhali p. overcoming poverty and inequality in south africa: an assessment of drivers, constraints and opportunities. washington, dc: world bank group; 2018. http:// documents.worldbank.org/curated/en/530481521735906534 12. van pelt kl, allred d, cameron kl, et al. a cohort study to identify and evaluate concussion risk factors across multiple injury settings: findings from the care consortium. inj epidemiol 2019;6(1):1. [https://dx.doi.org/10.1186/s40621-0180178-3] [ pmid: 30637568] 13. lariviere k, bureau s, marshall c, et al.. interaction between age, sex, and mental health status as precipitating factors for symptom presentation in concussed individuals. j sports med (hindawi publ corp) 2019;2019:9207903. [https://dx.doi.org/ 10.1155/2019/9207903] [pmid: 31976333] 14. brooks bl, silverberg n, maxwell b, et al. investigating effects of sex differences and prior concussions on symptom reporting and cognition among adolescent soccer players. am j sports med 2018;46(4):961-968. [https://dx.doi.org/10.1177/0363546517749588][pmid: 29323926] 15. iverson gl, gardner aj, terry dp, et al. predictors of clinical recovery from concussion: a systematic review. br j sports med 2017;51(12):941-948. [https://dx.doi.org/10.1136/bjsports-2017097729] [pmid: 28566342] 16. legarreta ad, brett bl, solomon gs, et al. the role of family and personal psychiatric history in postconcussion syndrome following sport-related concussion: a story of compounding risk. j neurosurg pediatr 2018;22(3):238-243. [https://dx.doi.org/ 10.3171/2018.3.peds1850] [pmid: 29856298] 17. abrahams s, fie sm, patricios j, et al.. risk factors for sports concussion: an evidence-based systematic review. br j sports med 2014;48(2):91-97. [https://dx.doi.org/10.1136/bjsports-2013092734] [pmid: 24052371] 18. putukian m, riegler k, amalfe s, et al. preinjury and postinjury factors that predict sports-related concussion and clinical recovery time. clin j sport med 2021;31(1):15-22. [https://dx.doi.org/10.1097/jsm.0000000000000705] 19. asken bm, houck zm, bauer rm, et al. scat5 vs. scat3 symptom reporting differences and convergent validity in collegiate athletes. arch clin neuropsychol 2020;35(3):291-301. [https://dx.doi.org/10.1093/arclin/acz007][pmid: 30796799] 20. broshek dk, kaushik t, freeman jr, et al. sex differences in outcome following sports-related concussion. j neurosurg 2005;102(5):856-863. [https://dx.doi.org/10.3171/jns.2005.102.5.0856][pmid: 15926710] 21. covassin t, schatz p, swanik cb. sex differences in neuropsychological function and post-concussion symptoms of concussed collegiate athletes. neurosurgery 2007;61(2):345-350. [https://dx.doi.org/10.1227/01.neu.0000279972.95060.cb]pmid: 17762747] 22. black am, sergio le, macpherson ak. the epidemiology of concussions: number and nature of concussions and time to recovery among female and male canadian varsity athletes 2008 to 2011. clin j sport med 2017;27(1):52-56. [https://dx.doi.org/ 10.1097/jsm.0000000000000308] [pmid: 26862834] 23. merritt vc, greenberg ls, guty e, et al. beyond measures of central tendency: novel methods to examine sex differences in neuropsychological performance following sports-related concussion in collegiate athletes. j int neuropsychol soc. 2019;25(10):1094-100. [.doi: 10.1017/s1355617719000882][pmid: 31477193] https://dx.doi.org/10.1136/bjsports-2017-097699 https://dx.doi.org/10.1136/bjsports-2017-097699 https://dx.doi.org/10.1016/j.csm.2017.05.002 https://dx.doi.org/10.1111/sms.13644 https://dx.doi.org/10.1111/j.1365-2923.2001.00726.x https://dx.doi.org/10.1007/s40279-015-0335-6 https://dx.doi.org/10.1186/s40621-018-0178-3 https://dx.doi.org/10.1186/s40621-018-0178-3 https://dx.doi.org/10.1177/0363546517749588 https://dx.doi.org/10.1136/bjsports-2017-097729 https://dx.doi.org/10.1136/bjsports-2017-097729 https://dx.doi.org/10.1136/bjsports-2013-092734 https://dx.doi.org/10.1136/bjsports-2013-092734 https://dx.doi.org/10.1097/jsm.0000000000000705 https://dx.doi.org/10.1093/arclin/acz007 https://dx.doi.org/10.3171/jns.2005.102.5.0856 https://dx.doi.org/10.1227/01.neu.0000279972.95060.cb editorial 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license major steps in 2021 the south african journal of sports medicine (sajsm) took major steps in 2021. seventy-nine submissions were received during the year with 37 submissions getting accepted for publication after review. this is a record. the 53% rejection rate may seem harsh, but not when compared to the top journal in the field (british journal of sports medicine) which has a rejection rate of 78%. the sajsm’s abstracts were viewed 8746 times, and 5064 pdfs were downloaded during the year. the highlight of the year was receiving the news that the journal passed the national library of medicine’s scientific quality review. the journal’s papers from 2019 onwards will be included in the ncbi’s pubmed central database. a full listing of the other databases which cover the sajsm is described in the index/listing section of journal. the growth of the journal can be attributed to several factors. firstly, the small but dedicated support staff working tirelessly to maintain the workflow from the time a paper enters the review process. secondly, the stable platform from which to host the journal. this was provided by the academy of science of south africa (assaf). their management team was superb in maintaining the publication’s platform and responding to queries. this had a major impact on the growth of the journal and is aligned with their goal of ’growing the peer-reviewed open access scholarly journals in south africa’. a third factor contributing to this journal’s growth is the expanding pool of reviewers. many reviewers were drawn from the membership of the south african sports medicine association, which reflects the maturity of the organisation. reviewers from overseas institutions were also recruited. in the majority of cases the quality of reviews was high. reviewing is a time-consuming job for which there is no public recognition. without these highquality reviews it is not possible to raise the standard of the published work. it is for this reason that much gratitude is extended to all the reviewers of 2021. another pleasing aspect of 2021 was that the publications represented eleven institutions from around the country (cape peninsula university of technology, iie’s varsity college, nelson mandela university, stellenbosch university, tshwane university of technology, university of cape town, university of johannesburg, university of kwazulu-natal, university of pretoria, university of the free state, university of the witwatersrand). this shows the discipline of sports medicine has spread throughout the country and is not the domain of a few universities as it was a decade ago. papers were also received from institutions in zimbabwe, mauritius, kenya, england and ireland. there are still challenges ahead. during the covid pandemic the “scientific process” has been stress-tested. political influence has crept into a few high level medical journals. this has been divisive and destructive to the scientific process. politics and science have to remain separate. mixing the two creates a murky environment to the detriment of both. journals have a role to play in maintaining the integrity of the scientific process. they can do this by ensuring that the review process is fair and rigorous. a rigorous review considers the research question and design of the study. are the results believable? do the conclusions match the results? are any biases acknowledged? there should be no influence from outside sources with a preferred outcome of the study. these include advertisers, policy makers, and scientists invested in a particular finding. failure of journals to uphold these basic principles of the review will contribute to the further contamination of the scientific process. as mentioned earlier, the discipline of sport and exercise medicine has matured. but fundamental questions remain important. for example; what is the best training approach to reduce the risk of injury? what impact does injury during competition have on the athlete’s quality of life after they have retired? what are the positive effects of regular exercise on quality of life? researchers have tried to answer these questions using measurements available at the time of the research. as new measurement techniques become available further insight into these questions are possible. the health and fitness industry has been flooded with new wearable technology with a variety of sensors (e.g. electrochemical, optical, acoustic, and pressuresensitive). [1] accelerometers, gyroscopes and real-time position detectors are also included in some devices. these sensors can measure heart rate, ecg, emg, tissue oxygenation, lactate, temperature, distribution of plantar pressure, acceleration of body segments, and speed while exercising. as the sensors have become more sophisticated, the potential for greater data collection has increased. this opens opportunities for studies using machine learning and artificial intelligence. this has provided an opportunity to use big data mining analytics to answer specific questions that could not be answered in the same way previously. for example, the fitbit company has patented an algorithm which identifies depression and predicts bipolar conditions using data (sleep, resting heart rate and voice of the user) measured with the fitbit. [2] the accuracy of the prediction is unknown, but it indicates the potential to use a variety of measurements from wearable devices for clinical purposes. data scientists with expertise in artificial intelligence will be attracted to innovative applications of wearable technology using big data. there are many opportunities to revisit some of the fundamental questions and answer them using more sophisticated measurements. there is still much work to be done! mike lambert editor-in-chief s afr j sports med 2022;34:1. doi: 10.17159/2078-516x/2022/v34i1a13041 references 1. düking p, fuss fk, holmberg h-c, et al. recommendations for assessment of the reliability, sensitivity, and validity of data provided by wearable sensors designed for monitoring physical activity. jmir mhealth uhealth 2018;6(4):e102. [doi: 10.2196/mhealth.9341] [pmid: 29712629] 2. stables j. new fitbit patent targets depression and bipolar detection. december 28, 2021. https://www.wareable.com/fitbit/ new-fitbit-patent-targets-depression-and-bipolar-detection-8666 (accessed 07 january 2022) https://journals.assaf.org.za/index.php/sajsm/about https://www.assaf.org.za/index.php/programmes/scholarly-publishing-programme/online-scientific-writing https://www.assaf.org.za/index.php/programmes/scholarly-publishing-programme/online-scientific-writing http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13041 https://doi.org/10.2196/mhealth.9341 https://www.wareable.com/fitbit/%20new-fitbit-patent-targets-depression-and-bipolar-detection-8666 https://www.wareable.com/fitbit/%20new-fitbit-patent-targets-depression-and-bipolar-detection-8666 https://orcid.org/0000-0001-8979-1504 original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license dietary supplements and beverages: knowledge, attitudes, and practices among semi-professional soccer players in kwazulu-natal, south africa s nyawose,1 msc; r naidoo,1 phd; n naumovski,2,3,4 phd, maifst; aj mckune,1,3,5,6 dtech, cscs 1 discipline of biokinetics, exercise, and leisure sciences. school of health sciences, university of kwazulu-natal, durban, south africa 2 faculty of health, university of canberra, discipline of nutrition and dietetics, university of canberra, canberra, act, australia. 3 functional foods and nutrition research (ffnr) laboratory, university of canberra, ngunnawal country, act, australia. 4 department of nutrition and dietetics, harokopio university, athens 17671, greece. 5 faculty of health, discipline of sport and exercise science, university of canberra, canberra, act, australia. 6 research institute for sport and exercise, university of canberra, canberra, act, australia. corresponding author: s nyawose (nyawoses2@ukzn.ac.za) dietary supplements include food components, nutrients and non-food compounds ingested in addition to a habitually consumed diet to achieve specific health and/or performance benefits.[1] for the purpose of this study, these dietary supplements are typically in the form of tablets, capsules, soft gels, energy bars, and powders. soccer players commonly consume dietary supplements, and sports and energy beverages, before, during, or after a soccer match.[2] sports beverages, are typically ingested to hydrate and restore electrolytes and carbohydrates; whereas energy beverages have caffeine as the main ingredient, with the goal of improving cognitive ability.[3] soccer is a competitive sport that involves intermittent, high-intensity activities interposed with low-intensity activities.[3] a decline in any performance component can decide the outcome of a soccer match. therefore, the strategic use of substances that improve hydration, energy and cognitive ability to enhance performance is attractive to soccer players.[4] commercially available dietary supplements and beverages appeal to athletes for their supposed ergogenic effect, mainly due to aggressive marketing strategies.[5] studies have reported widespread usage of dietary supplements in soccer players. more than 82% of dietary supplement usage has been reported among elite soccer players recruited from international tournaments.[6] at the summit of world soccer, a retrospective study reported an increase in dietary supplement use during russia's 2018 world cup tournament, compared to the 2014, 2010, 2006, and 2002 world cup tournaments.[7] beverages are consumed at any time during a soccer match, with consumption of energy beverages by soccer players primarily before or during a game.[2] sports and energy beverages are also commonly known about and used by amateur athletes.[8] this increasing trend in the use of supplements is also evident in african countries. fifty-one per cent of soccer players in the zimbabwean league used dietary supplements, mainly vitamins (20%) and minerals (17%); while 15% reportedly consulted traditional healers for herbal supplements.[9] all 200 participants in an algerian study background: the ingestion of dietary supplements and beverages is prevalent in soccer, at the amateur and professional level. the absence of professional advice at non-professional level makes amateur soccer players susceptible to ingesting unsafe supplements. objectives: to determine the knowledge, attitudes and practices of abc motsepe league (semi-professional) players in kwazulu-natal regarding the use of dietary supplements and beverages. methods: three hundred and forty-three soccer players participated in a cross-sectional study. knowledge, attitudes and practices were determined using a questionnaire. researchers visited twelve teams. on the day of the visit to each team, information sheets and questionnaires were given to participants. questionnaires were collected immediately following completion. descriptive statistics were used, including means and standard deviations, where applicable. inferential statistics, chi-square and binomial tests were used to analyse the results. statistical significance was set at p < 0.05. results: sports beverages were the most recommended and commonly used, followed by energy beverages. dietary supplements were the least-known used. participants used beverages and dietary supplements to assist in providing more energy (67%), improve health (65%) and improve performance (55%) (p<0.001). seventy-three percent of participants lacked knowledge about the anti-doping policy (p<0.001), with 87% having never attended a workshop on the safe use of supplements and beverages, or anti-doping awareness campaigns (p<0.001). thirty-eight percent had not heard of the south african institute for drug-free sport (saids), and 84% were not familiar with the yearly updated world anti-doping agency’s (wada) prohibited list (p<0.001). of the 59% who did not take dietary supplements or beverages, 75% had insufficient information regarding them (p<0.001), 66% indicated that dietary supplements and beverages were costly (p=0.001), and 55% indicated they did not need dietary supplements and beverages (p=0.32). conclusion: there is a need for an educational programme on the safe use of dietary supplements, and sports and energy beverages among kwazulu-natal semi-professional soccer players. keywords: performance enhancement, sports drinks, anti-doping, abc motsepe league s afr j sports med 2022;34:1-6. doi: 10.17159/2078-516x/2022/v34i1a14018 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a14018 https://orcid.org/0000-0002-2841-4497 https://orcid.org/0000-0002-9664-3734 https://orcid.org/0000-0001-8843-8450 https://orcid.org/0000-0002-5479-1544 original research sajsm vol. 34 no.1 2022 2 indicated that they used dietary supplements to improve performance.[10] south african athletes, including amateur soccer players, are no different, with the vitamin and supplement market in south africa growing at around 11% annually.[11] their use is more evident in elite athletes than in non-professional athletes. however, limited research has been conducted to compare use at the different performance levels. non-professional athletes typically have limited professional support to guide them in the safe use of supplements.[12] the prevalence of supplement usage among non-professional athletes potentially increases the risks of using contaminated supplements. the frequent use of supplements is associated with a high risk of ingesting contaminated substances that may be harmful.[1] fifteen to 25% of supplements contain substances prohibited by world anti-doping agency (wada).[2] furthermore, many supplements come with insufficient scientific research or supporting evidence.[13] over the years, there have been cases against soccer players using prohibited substances in the south african premier division. in the province of kwazulu-natal, amateur soccer players use supplements, yet lacked knowledge about the risks associated with using these supplements.[8] this may lead to non-professional soccer players in kwazulu-natal becoming susceptible to using prohibited substances. to the best of the authors’ knowledge, there is currently no published data on the knowledge about, attitudes to, and practices of, dietary supplement and beverage use among semi-professional soccer players in south africa. therefore, this study aimed to determine the knowledge and use of dietary supplements and beverages among abc motsepe league players in kwazulu-natal. methods participants and study design this study used a descriptive, observational, cross-sectional survey design. the researchers relied on a self-administered questionnaire to explore the participants’ practices and perceptions. the abc motsepe league usually features 144 teams, divided into nine 16-team provincial divisions. twenty teams were affiliated with the kwazulu-natal league during the 2021-2022 season. teams affiliated to the kwazulu-natal league were approached to participate in the study. sixteen teams were contacted telephonically, with thirteen accepting the invitation to participate. however, one team was not available on the day the researchers visited the teams for data collection. therefore, 12 teams participated in the study. three hundred and forty-three participants completed questionnaires. this meant a 95% questionnaire response rate. using a margin of error of 5% and an alpha level of .05 from a population of 600 the required sample size would be 234. cochran’s sample size formula for categorical data was used to calculate the study’s sample size, and for a population size of 600, cochran’s correction formula was used to calculate the final sample size.[14] data collection the dietary supplement questionnaire was used to determine knowledge, attitudes and practices regarding dietary supplements and beverages among abc motsepe league players in kwazulu-natal. the questionnaire was adapted from a reliable and validated questionnaire.[12] the questionnaire was explained to participants in english and isizulu. the questionnaire was comprised of four sections. section a focused on general information; section b focused on knowledge about dietary supplements and sports and energy beverages; while section c focused on attitudes to dietary supplements and sports and energy beverages. section d focused on the use of dietary supplements and sports and energy beverages. this section was divided into two subsections: one for participants who used supplements and the other for participants who did not. a pilot study was conducted with 12 players who played one division lower than the study population. based on positive feedback from the participants, no changes were necessary. ethical considerations the university of kwazulu-natal’s biomedical research ethics committee (00001656/2020) approved the study. the south african football association’s (safa) kwazulu-natal provisional executive council granted permission to conduct the research and provided a list of teams with the contact details of the team managers. researchers visited twelve teams. on the day of the visit to each team, information sheets were handed out to prospective participants. the purpose of the study was explained in detail to the soccer players in the presence of the team management and technical team. players interested in participating in the study signed consent, or assent forms for those under 18 years were completed, and the team manager signed consent. questionnaires were handed out to participants, completed, and collated on the same day. statistical analysis data were analysed using the statistical package for social science (spss) 21.0 (ibm corp. released 2013. ibm spss statistics for windows, version 22.0. armonk, ny: ibm corp). descriptive statistics were used, including means and standard deviations, where applicable. inferential statistics, including the chi-square goodness of fit test, were used to perform univariate analysis on categorical variables to test whether any of the response options were selected significantly more or less often than the others. sample size varied as a consequence of participants not completing all questions. statistical significance was set at p<0.05. results participants’ ages ranged from 16 to 35 years. the mean age was 24 ± 4 years, with 60% having played in the abc motsepe league for less than four years and 40% playing for more than four years. of the players, 34% played in the midfield positions; 31% played as defenders; 24% played forward positions; and 11% were goalkeepers. original research 3 sajsm vol. 34 no.1 2022 knowledge about dietary supplements and beverages when participants were asked to indicate agreement with the statement that consuming supplements replaces a healthy balanced diet, results showed neither significant agreement nor significant disagreement (p=0.28). table 1 lists the supplements and beverages that abc motsepe league soccer players in kwazulu-natal consider ideal for soccer players, based on their knowledge. a significant number of the participants responded that soccer players' sports beverages were ideal for consumption: 74% recommended carbohydrate sports beverage a and 61% recommended carbohydrate sport beverage b (p<0.001). a significant number of participants did not recommend supplements, such as creatine (84%), nitrate (86%), or sodium bicarbonate (92%), as ideal for consumption by soccer players (p<0.001). however, 51% of players recommended protein shakes as an ideal supplement for soccer players (p=0.75). knowledge of anti-doping agencies table 2 presents participant responses relating to their knowledge of anti-doping agencies: the world anti-doping agency (wada) and the south african institute for drugfree sport (saids). a significant number of participants (73%) had no access to anti-doping information, while 87% had never attended a workshop or presentation on dietary supplement or beverages, or an anti-doping awareness campaign (p<0.001). a significant number of participants (84%) were not familiar with the yearly updated wada prohibited list (p<0.001). a significant proportion of participants, 38% and 48%, had never heard of the saids or wada, respectively. while 35% and 30% had heard of saids and wada, respectively, they did not know anything substantial (p<0.001). attitudes to dietary supplements and beverages when questioned on their attitudes to dietary supplements and beverages, 73% disagreed that all supplements are safe, and 59% disagreed that taking dietary supplements is cheating (p<0.001). participants (70%) agreed that it was necessary to read the nutritional guidelines for a dietary supplement or beverage product (p<0.001), while 67% agreed that the type, quantity, and timing when taking dietary supplements or beverages was essential to receive the full benefits from that product (p<0.001). there were no significant differences in participants' responses when asked if the claimed benefits of dietary supplements and beverages are always based on scientific evidence (p=0.05). practices of dietary supplement and beverage use when asked about the beverages or supplements that participants had consumed the most in the previous month, sports beverages were the most consumed (23%), followed by energy beverages (6%), dietary supplements at 5%, and protein shakes were used by 2.8%. however, 0.7% of participants indicated they did not know the beverage name or dietary supplement they had consumed most in the previous month. there was no significant difference between players who consumed beverages before training or matches (57%) and players who did not consume beverages (43%), (p=0.92). of the participants, a significant 34% indicated that they followed the instructions on the beverage label or supplement label to help them decide on the amount to consume, while a significant 50% were unsure of how much to drink (p<0.001). a significant number of participants did not consult a professional (71%), ask a coach or teammates (72%), check the manufacturer’s websites (82%), or conduct any research (88%) about the safety of beverages or dietary supplements consumed (p<0.001). reasons for using dietary supplements and beverages study participants were asked to recall if they had consumed dietary supplements or beverages in the month prior to data collection. of the participants, 59% reportedly had not consumed dietary supplements or sports and energy beverages in the previous month, while 41% (n = 141) indicated that they had consumed dietary supplements and beverages in the month before data were collected. table 1. supplements, and sports and energy beverages, ideal for soccer players (%), as reported by participants (n=343) item frequency (%) p-value yes no caffeine 22 78 <0.001** creatine 16 84 <0.001** red bull® 41 59 0.001* nitrate 14 86 <0.001** protein shakes 51 49 0.75 carbohydrate beverage a (powerade®) 74 26 <0.001** carbohydrate beverage b (energade®) 61 39 <0.001** sodium bicarbonate 8 92 <0.001** * indicates p < 0.05, ** indicates p< 0.001. table 2. knowledge of anti-doping agencies (%) reported by participants (n=343) item responses as frequency (%) χ2 df p-value never heard of it heard of, know nothing about it heard of, know a little about it heard of, know quite a bit about it heard of, know a lot about it saids 38 35 20 3.8 3.5 186.8 4 <.001* wada 48 30 13 7.6 2.0 239.5 4 <.001* * indicates p< 0.001. saids, south african institute for drug-free sport; wada, world anti-doping agency; χ2, chi-square test; df, degrees of freedom original research sajsm vol. 34 no.1 2022 4 figure 1 lists reasons for consuming dietary supplements, and sports and energy beverages. participants used dietary supplements or beverages mainly to provide more energy (67%), improve health (65%) (p<0.001), and enhance sports performance (55%) (p=0.31). study participants indicated that they mainly relied on online sources (38%) and coaches (36%) for information on dietary supplements and beverages. table 3 lists participants’ reasons for not taking supplements or sports and energy beverages. participants disagreed that the consumption of supplements and beverages is a form of cheating (p < 0.02) and disagreed that supplements and beverages are unhealthy (p < 0.003). participants agreed that supplements and beverages are often too expensive and that they are concerned about failing a drug test if they were to be tested (p < 0.05). furthermore, participants agreed that they do not know enough about supplements and beverages (p <0.001). discussion the study aimed to determine the knowledge, attitudes, and practices of the abc motsepe league (semi-professional) soccer players in kwazulu-natal regarding the use of dietary supplements and beverages. there are limited studies that have focused on elite soccer players.[15] similarly, there is a lack of published literature on dietary supplements and beverages in the south african professional, semi-professional and nonprofessional leagues. some of the information discussed below has been gathered from different levels of sport and recreation. dietary supplements are not substitutes for a balanced nutritional programme for athletes.[1] however, responses from the current study showed neither significant agreement nor significant disagreement with the statement that ‘taking dietary supplements replaces a healthy balanced diet’. furthermore, of the participants who had not recently used supplements or beverages, the majority reportedly did not know enough about beverages and supplements. this suggests that the participants had relatively limited knowledge about dietary supplements. similarly, a study by jovanov et al. reported that less than 40% of amateur athletes knew about the proper intended use of dietary supplements.[12] however, professional players are relatively better informed about dietary supplements than amateur players.[16] a study on soccer players in the professional malawian super league reported an adequate understanding of supplements, with no need for educational interventions among the players.[17] this may indicate that at the professional level adequate education on dietary supplements is known, compared to lower divisions. differences in resources, such as the availability of professional advice and finances, may account for the reportedly superior knowledge in the professional game, compared to nonprofessional players. among athletes from the recreational to elite levels, commercially available sports beverages are popular because of their marketed ergogenic effect.[5] similarly, in the current study, sports beverages were the most recommended as ideal for improving soccer players' performance. protein shakes were the second most known and recommended supplement to enhance the performance of soccer players, preferred to other supplements, such as creatine, nitrate and sodium bicarbonate. a similar interest in, and popularity of, protein supplements was reported in johannesburg gym attendees.[18] maughan et al. cautioned athletes to assess whether minor benefits from dietary supplements exceed the risks of unintentional doping.[1] the responses of the semiprofessional league soccer players in the present study showed a substantial lack of knowledge fig. 1. reasons for using dietary supplements and beverages (%) reported by participants (n=141) table 3. reasons for not using dietary supplements or sports and energy beverage reasons n score t df p-value i do not need supplements and beverages. 196 3.6 ± 1.7 0.99 195 0.32 they are unhealthy. 196 3.2 ± 1.5 -2.98 195 0.003* they are too expensive. 196 3.9 ± 1.5 3.48 195 0.001* i do not know enough about supplements and beverages. 195 4.3 ± 1.4 7.93 194 <0.001** i am concerned about a positive drug test. 196 3.8 ± 1.6 2.98 195 0.003* taking supplements or energy beverages is like cheating. 196 3.2 ± 1.6 -2.35 195 0.020* * indicates p < 0.05, ** indicates p< 0.001. scored on likert scale from 1 to 6. score expressed as mean ± standard deviation. results were interpreted as significant agreement if the mean score >3.5 or significant disagreement if the mean score <3.5. df, degrees of freedom. original research 5 sajsm vol. 34 no.1 2022 of the wada list of prohibited substances, which suggests that players are at a high risk of using prohibited substances. a similar knowledge gap was reported in a recent scoping review on non-professional players, especially with regard to the health risks associated with consuming supplements.[19] furthermore, most players had limited to no knowledge about anti-doping agencies, such as saids and wada. lack of proper guidance on the risks associated with supplements increases the risk of doping and its adverse effects on the athletes’ health.[2] despite the players indicating that they are not fully knowledgeable about the risks associated with consuming dietary supplements, their attitude to dietary supplements seemed to indicate otherwise. participants disagreed that all supplements are safe for consumption, and the majority of participants (59%) indicated that they did not consume supplements because they considered them unhealthy. this attitude is supported by a study that advised exercising caution when using supplements or beverages as any compound that may enhance performance has the potential to adversely affect one’s health.[1] however, in the current study it may be possible that participants were not familiar with the names of supplements or beverages. despite the cautious attitudes regarding the consumption of dietary supplements and sports and energy beverages displayed by some participants, it is well known that supplementation is common among soccer players.[1] fortyone per cent of participants used sports beverages to enhance their performance during soccer matches or training.[1] similarly, a study by coopoo et al. reported that large quantities of carbohydrate supplements were consumed by gym attendees.[18] sports beverages promote hydration by replenishing electrolytes and supplying carbohydrates.[20] the strategic use of substances that improve hydration is deemed important in soccer players, given the few opportunities to hydrate during a soccer match.[2] energy beverages were the second most consumed beverage in this study. this may be due to the benefits attributed to caffeine-containing beverages in improving gross motor skills and concentration during a match.[21] a study on amateur soccer players reported that coaches recommended energy drinks to players.[8] in the current study, participants mainly relied on online sources and coaches for advice in choosing a supplement for use. athletes frequently use caffeine-containing beverages before a soccer match to enhance performance.[2] the present study found that 57% of participants consumed beverages before a match or training session. however, it may be of concern that soccer players believed that drinking more is better in order to have an edge over the opposition. non-professional athletes might be susceptible to excessive energy beverage consumption by thinking that this will increase their performance further. limitations the study’s findings should be interpreted cautiously, since the study used a self-administered questionnaire. it is essential to acknowledge the possibility of recall bias while responding to the questionnaire, and the likelihood of not providing an honest answer. players’ understanding of terminology in the questionnaire may have been another limitation. however, the questionnaire was explained to all participants in english and isizulu. conclusion the kwazulu-natal abc motsepe soccer players displayed a cautious attitude to using dietary supplements and sports and energy beverages possibly because of the evidence, and substantial lack of knowledge about the proper consumption of supplements. furthermore, users of supplements in this study were at risk of unintentional doping because of their limited or no access to educational platforms from anti-doping agencies, such as saids and wada. there is an urgent need for educational programmes to promote awareness about the safe use of dietary supplements and sports and energy beverages in the kwazulu-natal abc motsepe league. such programmes should teach soccer players about prohibited substances, thus avoiding unintentional doping and the potential side effects that impact health. conflict of interest and source of funding: the authors declare no conflict of interest. the authors would like to thank the national research foundation for financial support. acknowledgements: the authors wish to acknowledge the contribution of dr z nyawose and mr t mohlomi in distributing the research questionnaires. author contributions: sn contributed to the conceptualisation, design, data collection, interpretation of data, drafting or critical revision for important intellectual content, and approval of the version to be published. rn, nn, and ajm contributed to conceptualisation and the critical revision of the paper. all authors approved the version to be published. references 1. maughan rj, burke lm, dvorak j, et al. ioc consensus statement: dietary supplements and the high-performance athlete. br j sports med 2018;52(7):439-455. [doi: 10.1136/bjsports-2018099027] [pmid: 29540367] 2. oliveira c, ferreira d, caetano, c, et al. nutrition and supplementation in soccer. sports 2017;5(2):28 [doi: 10.3390/sports5020028] [ pmid: 29910389] 3. del coso j, munoz-fernández ve, munoz g, et al. effects of a caffeine-containing energy drink on simulated soccer performance. plos one 2012;7(2):1-8. [doi: 10.1371/journal.pone.0031380] [pmid: 22348079] 4. fernandes h. dietary and ergogenic supplementation to improve elite soccer players' performance. ann nutr metab 2021;77(4):197-203. [doi: 10.1159/000516397] [ pmid: 34120108] 5. peeling p, binnie mj, goods ps, et al. evidence-based supplements for the enhancement of athletic performance. int j sport nutr exerc metab 2018;28(2):178-187. [doi: 10.1123/ijsnem.2017-0343] [pmid: 29465269] 6. oliveira cb, sousa m, abreu r, et al. dietary supplements usage by elite female football players: an exploration of current practices. scand j med sci sports 2022; 32 suppl 1:73-80. [doi: 10.1111/sms.14001] [pmid: 34087016] 7. oester c, weber a, vaso m. retrospective study of the use of original research sajsm vol. 34 no.1 2022 6 medication and supplements during the 2018 fifa world cup russia. bmj open sport exerc med 2019;5(1): e000609. [doi: 10.1136/bmjsem-2019-000609] [pmid: 31548910] 8. kisten t, naidoo r. the perspectives of amateur soccer players and their coaches on the use of performance enhancing substances. glob j health sci 2019;11(7):154-163. [doi: 10.5539/gjhs.v11n7p154] 9. mkumbuzi n, kaseke f. use of non-steroidal antiinflammatory drugs and nutritional supplements in zimbabwean football. s afr j sports med 2015;27(1):20-22. [doi: 10.7196/sajsm.577] 10. chabaiki i, bakadi a, bechikh y. sports supplements: use, knowledge, and risks for algerian athletes. nor afri j food nutr res 2020;4(7):231-239. [doi: 10.51745/najfnr.4.7.231-239] 11. insight survey. how well is sa’s vitamins and supplements market? 2018. https://www.insightsurvey.co.za/well-sasvitamins-supplements-market (accessed 15 march 2022). 12. jovanov p, dordic v, obradovic b, et al. prevalence, knowledge and attitudes towards using sports supplements among young athletes. j int soc sports nutr 2019;16(1):27-36. [doi: 10.1186/s12970-019-0294-7] [ pmid: 31272457] 13. baltazar-martins g, brito de souza d, aguilar-navarro m, et al. prevalence and patterns of dietary supplement use in elite spanish athletes. j int soc sports nutr 16(1):30.[doi: 10.1186/s12970-019-0296-5] [pmid: 31319850] 14. bartlett je, kotrlik jw, higgins cc. organizational research: determining appropriate sample size in survey research appropriate sample size in survey research. inf technol learning, performance j 2001;19(1):43-50. 15. collins j, maughan rj, gleeson m, et al. uefa expert group statement on nutrition in elite football. current evidence to inform practical recommendations and guide future research. br j sports med 2021;55(8):416. [doi: 10.1136/bjsports-2019-101961] [ pmid: 33097528] 16. knapik jj, steelman ra, hoedebecke ss, et al. prevalence of dietary supplement use by athletes: systematic review and metaanalysis. sports med 2016;46(1):103-123. [doi:10.1007/s40279-015-0387-7] [pmid: 26442916] 17. kaoche jm, rintaugu eg, kamenju j, et al. knowledge on doping among football athletes, coaches and sponsors in malawi. j phys educ sport manag 2020;11(2):5-13. [doi: 10.5897/jpesm2020.0346] 18. coopoo y, mccreanor x, gabriels g. nutritional supplements use, cost, source of information, and practices by johannesburg north gym goers. s afr j sports med 2020;32(1):1-6. [doi: 10.17159/2078-516x/2020/v32i1a6771] 19. harmse b, noorbhai h. sport supplement use among high school rugby players in south africa: a scoping review. s afr j sports med 2022;34(1):1-9. [doi: 10.17159/2078-516x/2022/v34i1a13348] 20. pound cm, blair b, canadian paediatric society, nutrition and gastroenterology committee, ottawa, ontario. energy and sports drinks in children and adolescents. paediatr child health 2017;22(7):406-410. [doi: 10.1093/pch/pxx132] [pmid: 29491725] 21. shabir a, hooton a, spencer g, et al. the influence of caffeine expectancies on simulated soccer performance in recreational individuals. nutrients 2019;11(10):2289. [doi: 10.3390/nu11102289] [pmid: 31557945] https://www.insightsurvey.co.za/well-sas-vitamins-supplements-market https://www.insightsurvey.co.za/well-sas-vitamins-supplements-market original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license hand trauma in english domestic professional county cricket wj ribbans,1,2,3 phd, frcs (tr and orth), ffsem (uk); ms chaudhry,1 mbchb, mrcgp, bsc (hons); b goudriaan,1 mcsp 1 northamptonshire county cricket club, northampton, england. 2the university of northampton, northampton, england. 3the county clinic, 57 billing road, northampton, england nn1 5db corresponding author: wj ribbans (billribbans@billribbans.com) the incidence of injury in cricket has been reported to be increasing.[1,2] lower limb injuries have been recorded at between 23-50% of total injuries.[3,4] the upper limb accounts for between 20-34% overall, with hand and wrist injuries most strongly represented.[1,3,5,6,7] hand injuries mainly affect the digits as fractures and dislocations. hand trauma can occur during any of the main activities – batting, bowling, and fielding (including wicket-keeping). however, fielding has been repeatedly reported to be where most of the injuries occurmainly via direct impact with the ball or ground.[1,2,8,9,10] injuries can occur pre-season and during the season, during matches and training. the aim of this study was to investigate the incidence and mechanism of hand injuries in a professional cricket club over a decade and to assess the impact of these injuries on the availability of playing squad members. methods injuries to players at the northamptonshire county cricket club (nccc) were recorded on a computerised injury surveillance programme to which the players had consented. subsequently this data was available for analysis and auditing. the period of study was from 2009-2018 (ten seasons). two of the authors (wr and bg) were affiliated to the nccc throughout the study period. the competitive season for cricket lasts between the months of april and september. during this time, the club is involved in three competitive formats – the county championship (four day games), 50-over 1-day games, and 20/20 competitions. in addition, there are pre-season games, matches against touring countries, and second xi games. hand injuries were defined as any injury distal to the base of the metacarpals for the purpose of this analysis. the injuries included osseous, articular, and soft tissue damage. imaging was available for bone and joint injuries. the number of players available to the senior squad was recorded. although some players may feature predominantly (or exclusively) in one or two of the formats only, each individual was recorded as being available throughout the entirety of the season. the date of return-to-play (rtp) was used for defining injury recovery although it is acknowledged that a period of graduated training would need to be undertaken beforehand. if an injury occurred pre-season or the recovery continued after the season ended, the time the player was unavailable for selection during the season, as well as the total length of recovery, was measured. players requiring out-of-season rehabilitation for injuries remained at the club for treatment with one of the authors (bg). this allowed an assessment of the timing of full cricket-related recovery. results forty-five injuries to twenty-two different players were recorded over the ten-year period of study. none were recurring injuries. type and site of injury purely non-articular fractures contributed to 31 (69%) of the total hand injuries and articular injuries (including dislocations, fracture-dislocations, tendon avulsions and ligament injuries for 13 (29%) of the injuries (fig. 1). the final injury was a nail bed haematoma which required time away from the game. the left hand was involved in 53% of injuries and the right hand in 47%. the little finger accounted for 24% of all injuries, ring finger 31%, middle 11%, index 9%, and thumb 24%. the metacarpals, including the metacarpophalangeal joints (mcpjs), were involved in 11% of injuries. table 1 provides analysis of the precise site of the injuries. although not this paper’s area of study, it should be noted that no wrist or carpal injuries were recorded over the study period. treatment five injuries (11%) required surgical intervention. the remainder of the injuries were treated conservatively. background: hand trauma is a frequent and disabling injury in cricket. however, there is limited published data on its impact on the sport at the elite level. objectives: this study investigated the incidence and mechanism of hand injuries in professional cricket over a decade and the impact of these injuries upon player availability. methods: a retrospective hand injury review at northampton county cricket club (nccc) over 10 years (2009-2018) was performed. all hand injuries had been contemporaneously documented. they were analysed for cause of injury, treatment, and time away from competitive play. results: there were 45 hand injuries in total. eleven percent needed surgical intervention. these hand injuries required a total recovery time of 1561 days, and in-season 1416 days were lost from competitive play. the injuries requiring surgery were unavailable for 229 total days during the season. a player had an annual 18% risk of sustaining a hand injury requiring time away from the sport and resulting in a 4% reduction in playing resources during a season. conclusion: hand injuries have major implications for player selection during the cricket season and place a potential burden upon the entire squad and the team’s success. keywords: digits, fractures, dislocations, injury s afr j sports med 2021;33:1-4. doi: 10.17159/2078-516x/2021/v33i1a10689 mailto:billribbans@billribbans.com http://dx.doi.org/10.17159/2078-516x/2021/v33i1a10689 https://orcid.org/0000-0002-3612-2857 https://orcid.org/0000-0003-2271-4306 original research sajsm vol. 33 no. 1 2021 2 timing and activities involved in injuries thirty-two (71%) of the injuries occurred during matches and 13 (29%) during practice sessions of which four (31%) occurred preseason. fifty-six percent of injuries occurred during fielding activities, 20% specifically while wicket-keeping, and 24% during batting. no injuries occurred during bowling. recovery from injuries the 45 injuries resulted in a total of 1561 days off for rehabilitation. during the season, a total of 1416 days lost. on average, a hand injury led to 31 days/player (range 0-89) time lost for selection for games. five injuries required surgery and the players were unavailable for 229 days during the ten seasons, resulting in an average of 46 days/ player time lost for selection. conservatively treated injuries resulted in 1187 days off during the season which averaged 30 days/player time lost for selection. most english professional cricket seasons last an average of 22 weeks. therefore, a club might expect to endure 92 % of the season with playing selection reduced because of a hand injury. during the ten-year period, northamptonshire had an average of 25 senior players available for selection across three formats. hand injuries reduced this capacity by 4%. table 1. anatomical location, treatment, timing, and cause of hand injuries thumb index middle ring little total total number of injuries 11 (24%) 4 (9%) 5 (11%) 14 (31%) 11 (24%) 45 anatomical location distal phalanx 5 2 5 7 3 22 (49%) distal interphalangeal joint (including mallet finger injuries) 0 0 0 1 4 5 (11%) middle phalanx 0 1 0 2 1 4 (9%) proximal interphalangeal joint (including ligamentous injury) 1 0 0 1 1 3 (7%) proximal phalanx 3 0 0 0 2 5 (11%) metacarpophalangeal joint (including ligamentous injury) 0 0 0 0 0 0 metacarpal injuries 2 0 0 3 0 5 (11%) soft tissue injuries (excluding above) 0 1 0 0 0 1 (2%) treatment conservative treatment 11 3 4 11 11 40 (89%) surgical treatment 0 1 1 3 0 5 (11%) timing of injuries matches 9 1 4 8 10 32 (71%) training 2 3 1 6 1 13 (29%) activity at time of injury batting 3 3 1 2 2 11 (24%) bowling 0 0 0 0 0 0 fielding (excluding wicket-keeping) 5 1 2 11 6 25 (56%) wicket-keeping 3 0 1 1 4 9 (20%) total time lost during season post-injury (days) 378 83 144 536 275 1 416 total time lost post-injury (days) 421 140 144 561 295 1 561 data are expressed as n or n(%), where % indicates the percentage of the total number of injuries. fig. 1. lateral x-ray of ring finger: large dorsal avulsion fragment at insertion of extensor digitorum longus (edl) following catching injury original research 3 sajsm vol. 33 no. 1 2021 discussion cricket is a popular global sport. the international cricket council (icc) has over 100 member countries affiliated to it.[11] whilst played as a non-contact sport between participants, injuries do occur and are common. impact injuries frequently result from contact between the hard ball and body parts. ball speeds during bowling can be greater than 160 km.h-1.[11] in addition, impact injuries occur from direct contact with the ground, another player, or the pitch boundaries.[12] injuries at both professional and recreational levels impact upon individual player performance and team success. however, the incidence of cricket injuries has been reported to be lower than in other common team sports[1,8] although injury rates have varied greatly in different publications. weightman recorded 2.6 injuries/10000 hours played [13], whilst orchard reported 24.2 injuries/10 000 hours played [1] – a tenfold difference. leary and white calculated an acute injury rate of 57.4/1 000 days of cricket played.[14] hammond recorded a match incidence of 3.2 injuries/1 000 hours exposure compared to 29.9 in soccer and 97.6 in rugby union.[9] injury surveillance reports indicate that a return to cricketing activities from all injuries occur in one week or less in 47.8 %, 28.4% within two to three weeks, and 23.8% over more than three weeks.[2] the differences in recorded rates may reflect the increasing sophistication of injury surveillance methods over time, the criteria used for recording an injury, and whether the publication concentrated upon one sport or involved ‘across sport’ comparisons with varying fixture scheduling and physical demands. this study demonstrates that hand injuries sustained in professional cricket have significant implications for player welfare, availability, and selection. these results constitute the longest continuous period of analysis (ten years) of any study on hand injuries in elite cricket. it represents the experience of the equivalent of 250 years exposure to playing the sport professionally. additionally, it calculates how long it takes to recover before play is resumed again and the impact on senior player availability during a professional season. a professional cricketer had an 18% annual risk of sustaining a hand fracture over the course of this study. whilst only 11% of the injuries required surgical intervention, the time away from the sport still averaged seven weeks. this emphasised the importance of hand comfort, strength, and flexibility to perform all of the necessary skills within the game. at any one time, coaching staff, managing an average squad of 25 players, could expect to lose throughout the season an average of one player to these injuries alone. our data indicate that both hands are at equal risk and the digits more prone to injury than the metacarpals and mcpjs. our study confirms the results from previous smaller studies that the ring and little finger are most at risk combining to cater for 56% of all injuries.[8] fielding activities were the most common cause of injury, similar to the findings in previous literature.[8],[15] batting and wicket-keeping activities are afforded some hand protection through the use of gloves but they are not immune to injury. the absence of any wrist or carpal injuries during the decade of analysis in this paper emphasises the burden the game places specifically on the digits. brooks’ [16] recent paper reports an australian experience of 90 hand fractures identified over a three-year period across many elite teams. their surgical intervention rate of 13% is similar to that in our study (11%). ninety-three percent of their fractures involved the thumb, 5th ray, and middle and distal phalanges of the index, middle and ring fingers – the ‘exterior bones’. this was comparable to our study with 89% of hand fractures. the return-to-play statistics between the two studies is also similar. conservatively treated injuries averaged 30 days in our study (32 days in australia) and 46 days for surgical cases (49 days in australia). ‘buddy strapping’ the 4th and 5th digits has previously been advocated to reduce injury during fielding practices [10] and would seem to be a reasonable precaution but without any proven data to support it. specific gloves for catching practice are available but provide better protection to the palm and metacarpals than the digits. it is acknowledged that players want to replicate the skill of catching during practice and compliance for the use of more constrained gloves might be low. an acknowledged limitation of this study includes the precise mechanism of fielding injuries whether they occurred via direct impact with the ball, contact with the cricket field, or other methods of injury. although the data recorded the format of game for match injuries, the sample size was too small for meaningful analysis of differential injury patterns in other competitions. conclusion hand injuries have major implications for player selection during the cricket season. coaching staff should be aware of the potential burden such injuries place upon the entire squad and the impact for a team’s sporting success. an evaluation of fielding techniques, practice drills, and future new protective equipment might contribute to a decrease in such injuries. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: wr; conceived the project, accumulated the audit data and assessed the imaging, wrote the manuscript and provided references. sc; analysed the data, wrote the manuscript and completed the literature review. bg; entered and retrieved all data for the audit of this project and provided input to the manuscript. references 1. orchard j, james t, alcott e, et al. injuries in australian cricket at first class level 1995/1996 to 2000/2001. br j sports med 2002;36(4):270-275. [doi: 10.1136/bjsm.36.4.270] [pmid: 12145117] 2. stretch ra. the incidence and nature of injuries in first-league and provincial cricketers. s afr med j 1993;83(5):339–342 [pmid: 8211430] 3. stretch ra, venter dj. cricket injuries: a longitudinal study of the nature of injuries to south african cricketers. s afr j sports med original research sajsm vol. 33 no. 1 2021 4 2005;17(3):4-9. [doi: 10. 17159/5122] 4. temple r. cricket injuries: fast pitches change the gentleman's sport. phys sportsmed 1982;10(6):186-192. [doi: 10.1080/00913847.1982.11947258] [pmid: 29261044] 5. stretch ra. a review of cricket injuries and the effectiveness of strategies to prevent cricket injuries at all levels. s afr j sports med 2007;19(5):129-132. [doi: 10.17159/2078516x/2007/v19i5a256] 6. russell jh, hughes jm, heskin l, et al. the pattern of hand injuries in amateur cricket. eur j plast surg 2014;37(5):281-286. [ doi: 10.1007/s00238-014-0932-x] 7. shah k, furniss d, collins gs, et al. cricket related hand injury is associated with increased odds of hand pain and osteoarthritis. sci rep2020;10(1), 16775. [doi: 10.1038/s41598020-73586-z ][pmid: 33033307] 8. ahearn n, bhatia r, griffin s. hand and wrist injuries in professional county cricket. hand surg 2015;20(1):89-92. [doi: 10.1142/s0218810415500124] [pmid: 25609280] 9. belliappa pp, barton nj. hand injuries in cricketers. j hand surg br 1991;16(2):212-214 [doi: 10.1016/0266-7681(91)90180-v] [pmid: 2061668] 10. hammond le, lilley jm, pope gd, et al. comparative injury rates in three professional team sports. basem. annual meeting. september 2009. poster presentation. 11. pardiwala dn, rao nn, varshney av. injuries in cricket. sports health 2018;10(3):217-222.[doi: 10.1177/1941738117732318] [pmid: 28972820] 12. shafi m. cricket injuries: an orthopaedist's perspective. orthop surg 2014;6(2):90-94. [doi: 10.1111/os.12104] [pmid: 24890289] 13. weightman d, browne rc. injuries in eleven selected sports. br j sports med 1975;9(3):136-141.[doi: 10.1136/bjsm.9.3.136] 14. leary t, white ja. acute injury incidence in professional county club cricket players (1985-1995). br j sports med2000, 34(2): 145147. [doi: 10.1136/bjsm.34.2.145] [pmid: 10786874] 15. finch cf, elliott bc, mcgrath ac. measures to prevent cricket injuries: an overview. sports med 1999, 28(4): 263-272.[doi: 10.2165/00007256-199928040-00004] [pmid: 10565552] 16. brooks k, orchard jw, saw ae, et al. hand fractures and return to play in elite australian cricketers. j orthop 2020;22:100-103. [doi: 10.1016/j.jor.2020.03.039] [pmid: 32308261]. doi:%2010.%2017159/5122 doi:%2010.1080/00913847.1982.11947258 doi:%2010.1080/00913847.1982.11947258 doi:%2010.17159/2078-516x/2007/v19i5a256 doi:%2010.17159/2078-516x/2007/v19i5a256 doi:%2010.1142/s0218810415500124 doi:%2010.1142/s0218810415500124 doi:%2010.1016/0266-7681(91)90180file:///c:/doi:%2010.1177/1941738117732318 doi:%2010.1111/os.12104 doi:%2010.1136/bjsm.9.3.136 doi:%2010.1136/bjsm.34.2.145 doi:%2010.2165/00007256-199928040-00004 doi:%2010.2165/00007256-199928040-00004 36 sajsm vol. 28 no. 2 2016 original research the perceived benefits of the maties injury programme among students hlp bates,1,2 b medsci; jh kirby,1 mb, chb, msc (sports med) 1 stellenbosch university centre for human performance sciences & campus health services, stellenbosch, south africa 2 college of medical and dental sciences, university of birmingham, birmingham, united kingdom corresponding author: jh kirby (jkirby@sun.ac.za) objective: to investigate how athletes attending the maties injury programme (mip) at stellenbosch university perceived the service, and to highlight areas they believed could be improved. participants: thirty athletes representing stellenbosch university attended the mip following injury in may 2014. methods: a questionnaire-based service evaluation to assess patients’ perceptions of the mip. results: ninety-three percent of participants indicated that they benefited from attending the injury clinic. across all domains in the questionnaire patients reported high levels of satisfaction with the mip. four participants made suggestions for improvement, which have been considered. conclusions: the theoretical benefits of pr oviding a sp ecialised sports injury assessment as part of the campus health services for athletes at stellenbosch university have been supported by the encouraging responses of patients. incorporating sports injury programmes into campus health services at more universities should be considered. keywords: service survey, high performance programme, injury clinic s afr j sports med 2016;28(2):36-38. doi:10.17159/2078-516x/2016/v28i2a170 doctors with experience and qualifications in identifying and treating sports injuries are best placed to establish which causative factors result in an injury and implement appropriate treatment.[1,2] many universities have therefore incorporated dedicated sports injury programmes into their campus health services. the maties injury programme (mip) at stellenbosch university is one such an example. the mip offers free and rapid specialist assessment of sports injuries sustained during training or participation in university sporting activities. assessing doctors can arrange for specialist referrals or further investigations. the costs are apportioned between maties sport and the stellenbosch university’s campus health services. the programme aims to provide a holistic approach to care by assessing the injury; providing information to the patients and an agreed tailored treatment and rehabilitation plan with the sportsperson, in addition to providing training adaption advice for coaches. there is little available literature documenting the perceived benefits of involving sports injury specialists in campus health services. similar constructs to the mip are available in the united states; however, no research could be identified in assessing patient perceptions. moreover, there is little published research investigating the perceptions of patients attending sports physicians, although it is possible that unpublished evaluations conducted within organisations may exist. appropriate patient support from the healthcare team can improve outcomes of sports injuries.[1,2] in sport, the use of a biopsychosocial patient assessment model with effective communication between the healthcare team and patient is vital to deal with the stresses and social pressures of competition.[2] successful communication and high levels of patient satisfaction are likely to contribute to better outcomes in injured patients. as well as good communication, understanding of the complexity of sports medicine is key in injury management at all levels. vergeer suggests family practitioners are often unable to deal satisfactorily with sports injuries because of insufficient training.[3] for elite varsity athletes, assessment by a sports physician is crucial to achieving overall optimal sports performance.[2] thorough knowledge of sports injuries is particularly important for treating first-year university athletes when dramatic increases in training intensity may result in chronic injuries. cooperation between healthcare professionals and coaches is essential to adapt programmes to meet individual needs, as well as to identify and address the social and psychological factors accompanying injuries.[2] the volume of supportive literature on the objective benefits of sports injury clinics suggest investigation of perceived (as opposed to objective) benefit is unnecessary. however, conducting a service evaluation to assist in assessing the success of the programme, and investigating the possibility that the mip and the communication of information to coaches could be perceived as a benefit to the team rather than to the individual. the secondary aim arose from concerns about the detrimental effect of such a perception on the relationship between the athlete and team doctor in elite sport.[4] the aim of this questionnaire-based service evaluation was to investigate how the athletes attending the mip perceived the service and to highlight areas they believed could be improved. methods a questionnaire-based service evaluation was used to assess patients’ perceptions of the mip over four weeks in may 2014. the study received written approval from the directors of maties sport, campus health services and centre for human performance sciences, university of stellenbosch. there was no available validated questionnaire to assess patients’ perceptions of benefits from a sports injury programme. therefore this study used seven questions based on the ‘medical interview satisfaction scale’;[5] a self-report questionnaire using a five-point likert scale that has been validated in south africa. the questionnaire was adapted to measure satisfaction with treatment from athletic trainers in injured athletes from previous research by replacing the word ‘illness’ with ‘injury’[5] (appendix 1). demographic data and injury type were recorded. patients were also asked to rate the perceived benefit from attending the clinic on a fivepoint likert scale, to identify the most beneficial aspect of attending the injury clinic and to suggest improvements. the questionnaire was piloted on three mip patients. no misunderstandings of the questions were noted. pilot responses were not included in the analysis. mailto:jkirby%40sun.ac.za?subject= http://dx.doi.org/10.17159/2078-516x/2016/v28i2a170 sajsm vol. 28 no. 2 2016 37 results were presented using descriptive statistics. the proportion of patients from each sport and mean age were assessed, as well as the distribution of traumatic and non-traumatic causes of injury. responses for each of the eight questions were analysed using a mean average calculation and standard deviation. qualitative responses were not sufficiently su bstantial fo r fu ll analysis but were grouped by theme and presented quantitatively. results thirty-three students attending the mip were approached – three declined to participate. all patients (n=21 males, nine females) saw a qualified s ports d octor. th e me an ag e of th e students was 21 years (range: 18-32 years). rugby accounted for the largest proportion of injuries seen (40%, n=12) with hockey injuries the second most common (27%, n=8). the o ther i njuries w ere f rom s occer ( n=4), athletics (n=3), ultimate frisbee (n=1), badminton (n=1) and water polo (n=1). non-traumatic injuries accounted for 57% of all injuries (n=17). thirty responses were collected, with only one questionnaire incomplete. figure 1 shows the distribution of the scale rating for each question and the mean response value with standard deviations. none of the participants ‘strongly disagreed’ with any of the statements. the majority of responses (82%) were positive (‘agree’ or ‘strongly agree’). only two statements did not have a mean score value corresponding with a positive response. statement 6: ‘after talking to the doctor i felt much better about my problems’ received the lowest average rating (3.8 ± 0.7) and statement 5: ‘the doctor has relieved my worries about being seriously injured’ had a mean rating of (3.9 ± 0.9). the final statement ‘overall i have benefitted from attending the sports injury clinic’ was the highest scored statement (4.6 ± 0.6) with 93% (n=28) of responses either ‘agree’ or ‘strongly agree’ and 7% (n=2) responding ‘uncertain’. twenty-four participants identified the aspect of the injury programme that they felt was most beneficial. f ive t hemes w ere identified: information about and assessment of an injury; rapid referral to specialist care; emotional support; convenience; and treatment. eighty three percent (n=20) of those that responded felt that the information about and the assessment of their injury were the most beneficial aspects of the injury programme. 6 fig. 1: perception of benefit likert responses 0% 20% 40% 60% 80% 100% strongly agree (5) agree (4) uncertain (3) disagree (2) strongly disagree (1) fig. 1: perception of benefit likert responses four participants provided suggestions for improving the mip. the suggestions were: provision of an estimated duration of rehabilitation; funding of investigations; staff should be friendlier; and extension of clinic hours during competition times. discussion most participants (93%) agreed that they had benefited from attending the injury clinic – with the remainder indicating ‘uncertain’. most responses (82%) were ‘agree’ or ‘strongly agree’ for all the statements in the question naire, indicating a consistently positive per ception of the mip. overall, the participants reported high levels of satisfaction with the mip; in particular, the identification of the injury and its severity, its impact on the competition and the answering of queries. lowest rated statements pertained to the doctor’s impact on a patient’s emotional response to their injury. as the questionnaire was completed following the initial consultation, patients may have received disappointing news with regard to their injury assessment and the 38 sajsm vol. 28 no. 2 2016 lower scores for the statements five and six can be attributed to the variable nature of the results of the injury assessment. repeating the questionnaire after a patient’s recovery may result in changes of these scores. the encouraging responses of the participants in this study support the theoretical benefits of a dedicated sports injury programme within campus health services generally at stellenbosch university, as well as the continued provision of the mip. the consistent agreement with statements relating to communication of information suggests that holistic care is being provided.[1] the high level of patient satisfaction and the impressive coordination between healthcare professionals, coaches, managers and players make this programme a potential model for other universities. none of the responses commented on coaching or team influence in the evaluation of the mip – refuting furrow’s suggestion that injured sportspeople may feel sports doctors are provided primarily for the coach’s benefit.[4] the results indicate that the programme is seen as beneficial by the majority of patients and that the assessment and subsequent information provided is perceived as very valuable. this study also provided an avenue for patients to suggest changes which have been reported to the mip. limitations based on the experiences at the mip it can be observed that that younger players commonly present with non-traumatic injuries from the sudden increase in training as they move from school to university. many such injuries may have been missed due to the short duration of the study and its timing in the academic year. as these patients form a large proportion of mip patients, assessment of their perceptions following their initial assessment during and after rehabilitation, is an avenue for further research. there are inherent problems with questionnaire studies in general.[6] this questionnaire was limited by the inclusion of questions that were likely to be disadvantageous in the consultation – rewording or removal of these in future studies would be beneficial. incorporation of interviews and focus groups could also be considered.[6] conclusions despite the limitations of the study, it has provided useful preliminary data on the perceptions of students attending the mip, showing that it is regarded as beneficial by students. overall, this study has suggested that the patients attending the mip appreciate the rapid assessment and management advice given. the study has also shown that conducting service evaluations of the perceived benefits of existing sports injury programmes provides useful information both to health services and sports financers. the findings also add weight to the argument for the incorporation of more sports injury programmes in campus health services. references 1. macauley d, ed. oxford handbook of sport and exercise medicine. 2nd ed. london: oxford university press, 2013:35-63. isbn: 9780199660155. [doi: 10.1093/med/9780199660155.001.0001] 2. stanish wd, van aarsen m, evans na. the modernday team physician: roles, responsibilities, and required qualifications. in: micheli l, pigozzi f, chan km et al., eds. team physician manual: international federation of sports medicine (fims). 3rd ed. new york: routledge; 2013:3-9. isbn:  9780415505338 [doi: 10.1179/1753614613z.00000000050] 3. vergeer i. family physicians and sports-injury care: perceptions of coaches. can fam physician 1997;43:1755-1761. [pmid: 2255428] 4. furrow b. the problem of the sports doctor: serving two (or is it three or four?) masters. st. louis university law j 2005;50:165-183. 5. wolf mh, putnam sm, james sa, et al. the medical interview satisfaction scale: development of a scale to measure patient perceptions of physician behaviour. j  behav med 1978;1(4):391-40. [doi: 10.1007/bf00846695] 6. bowling a. research methods in health: investigating health and health services. buckingham, united kingdom: open university press; 1997:242-357. isbn-10 0335206433 [doi: 10.1002/sim.755] appendix 1. questionnaire used to assess patients’ perceptions of benefit from the sports injury programme gender: m / f (please circle) age: ______ sport: _________________________________ cause of injury: traumatic / non-traumatic please circle your response to each question. strongly disagree disagree uncertain agree strongly agree 1. the doctor told me the name of my injury in words that i could understand 1 2 3 4 5 2. after talking to the doctor, i know just how serious my injury is 1 2 3 4 5 3. the doctor told me all i wanted to know about my injury 1 2 3 4 5 4. the doctor told me how being injured will affect my ability to compete 1 2 3 4 5 5. the doctor has relieved my worries about being seriously injured 1 2 3 4 5 6. after talking to the doctor i felt much better about my problems 1 2 3 4 5 7. the doctor gave me a thorough check up 1 2 3 4 5 8. overall i have benefitted from attending the sports injury clinic today 1 2 3 4 5 what was the most beneficial part of your attendance at the clinic? __________________________________________________________________________________________________________ is there anything you think could be improved about the injury program at the clinic? __________________________________________________________________________________________________________ any other comments: thank you for completing this survey. http://dx.doi.org/10.1093/med/9780199660155.001.0001 http://dx.doi.org/10.1179/1753614613z.00000000050 http://dx.doi.org/10.1007/bf00846695 http://dx.doi.org/10.1002/sim.755 s afr j sports med 2022;34:1-66. doi: 10.17159/2078-516x/2022/v34i1a14885 thursday 29 september – sunday 2 october 2022 scientific abstract presentations index name abstract title o01 ms lizanne andrag similar medial knee contact force measures found in individuals with osteoarthritis and lower limb amputation: a systematic review o02 dr lone bogwasi management of proximal rectus femoris injuries do we know what we're doing?: a systematic review o03 mrs marise breet foot morphology of urban and rural south african children and adolescents o04 mr darren cecil an analyses of twitter-traffic on physical activity related messaging during the period of south africa's covid-19 lockdown o05 mr tawonga mwasevuma prevalence and correlates of adherence to total physical activity guidelines using step-counting in pre-school children: the sunrise study o06 ms siphesihle nqweniso disease burden of soil transmitted helminth infections on cardiovascular disease risk, physical activity and fitness in primary school children in port elizabeth, south africa o07 dr clement plaatjies the epidemiology of lower limb injuries during the super rugby tournaments (2013 2016) involving 76301 player-hours o08 prof hanlie moss physical activity, fitness and visual attention in young adults with depressive symptoms o09 dr maaike eken mental health profiles of healthcare professionals working during the tokyo 2020 and beijing 2022 paralympics games o10 prof heinrich grobbelaar african big-5 sport psychological assessment tool: development and preliminary validation o11 dr theron weilbach correlations between frequency of participation in campus recreation, leisure boredom, and satisfaction with life of undergraduate students o12 mr sindiso dube prevalence of the relative age effect among high performance, university athletes, versus an age matched student cohort o13 dr joseph siyakhuluma sibindi impact of biological maturity status on talented and non-talented male zimbabwean under-14 footballers o14 dr tsungai tirivashe marandure patellofemoral pain syndrome (pfps) is associated with chronic disease and allergies in 60 997 distance runner race entrants: a safer study o15 dr jordan leppan an abbreviated vs a comprehensive pre-race medical screening tool under-estimates runners at higher risk of medical encounters a safer study in 5771 race entrants http://dx.doi.org/10.17159/2078-516x/2022/v34i1a14885 o16 mr carel viljoen development of a trail running injury screening instrument: a multiple methods approach o17 mrs chanel smith five international pre-exercise medical screening tools vary greatly regarding their identification of running race entrants who require medical clearance: a safer study o18 mr lesego malele the prevalence of mental health disorders among semiprofessional cricketers residing in the western cape o19 dr steve den hollander the relationship between tackle technique measured in training and matches o20 mr simiso ntuli soccer players perception of soccer boot comfort a study to investigate soccer boots' suitability to soccer players' foot morphology o21 ms katelyne van den bergh index of coordination of running in triathletes o22 dr clement gambelli the effect of tibialis anterior weakness on foot drop and toe clearance in patients with facioscapulohumeral dystrophy o23 dr mark kramer the acute effects of schoolbag load on static and dynamic kinetics and kinematics in 10 -13 year old children o24 mrs danielle dolley clustered cardiovascular disease risk among 8 to 13 year old children from lower socioeconomic schools in gqeberha, south africa o25 prof estelle lambert does physical activity, in part, explain the lower-than-expected mortality from covid-19 in sub-saharan africa? o26 mrs sweetness makamu-beteck bring in the biokineticists: facilitating behaviour change in a lowresourced community o27 prof lucilia mangona energy expenditure, intensity, and perceived effort in recreational functional training o28 mrs marlise dyer environmental factors increase the risk of heat/electrolyte disorders in ultra-marathon races o29 mrs audrey jansen van rensburg the risk markers associated with acute respiratory tract illness in rugby players during the super rugby tournaments (2013 2017), involving 102 738 player-days o30 ms esme jordaan exercise associated muscle cramping is more severe for 56 km runners compared to 21.1 km runners o31 ms sonja swanevelder specific chronic allergies as predictors of annual multiple injuries in individual distance runners o32 dr maaike eken epidemiology of injuries in wheelchair rugby at the london 2012 and rio 2016 paralympic games o33 mrs kirsty elliott an epidemiological study into the prevalence and types of injuries affecting adolescent tennis players in south africa o34 dr antonio prista impact of sars -cov2 containment measures in physical activity and nutrition habits in african urban centres: a study in mozambique o35 dr phoebe runciman the incidence of illness and injury in master paralympic athletes: a descriptive cohort study of the 35 year age category in the 2012 to 2018 summer and winter paralympic games o36 dr leyekun gebru classification of junior ethiopian football players using anthropometric and physical fitness attributes: developing a predictive model o37 ms faatima adam injury profiles differ by athlete impairment type during the 2012 and 2016 summer paralympic games: a combined analysis of 101 108 athlete-days o38 ms sarah arnold muscle activation during the modified clinical test for sensory integration and balance (mctsib) in active unilateral transtibial amputees o39 ms lisa heyneke the comparison of lower limb kinematics across stroke rates among male rowers during ergometer rowing and the influence of lower limb strength o40 mrs cassidy de frança the effect of countermovement jump initiation detection methods on discrete performance variables o41 mr darius sangari eccentric movement strategy predicts stretch-shorten cycle preload during countermovement jumps o42 mr christo van zyl change of direction time vs change of direction deficit: is there a need to assess both? o43 prof ben coetzee cardiovascular autonomic nervous system-related discriminators of time trial power output in endurance trained athletes o44 mr mandisi sithole protein supplements in south africa: high protein-content products or a case of misinformation? o45 dr eirik halvorsen wik age, skeletal maturity and growth velocity as injury risk factors in elite youth football (soccer) players aged 11 to 15 years: a three season prospective study o46 mrs lynn smith development of a toolkit to assess health-related quality of life amongst patients with selected noncommunicable diseases o47 prof mkama andries monyeki body composition with nuclear and isotope technology application within the african region o48 ms gomes nhaca physical fitness of school-age children and youth living in an island in mozambique o49 dr tamrin veldsman associations between body composition, physical activity, intimamedia thickness, and cardio-metabolic risk factors in a cohort of teachers: the sabpa study o50 dr marelise badenhorst physiotherapists' experiences of rugby-related concussion management in the community o51 dr steve den hollander heading exposure in professional football training o52 prof johan van heerden reporting behaviours and attitudes to concussion among high school rugby players in kwazulu-natal, south africa o53 dr phoebe runciman injury and illness risk profiles in older active individuals: a systematic review clinical case presentations index name abstract title c01 dr lone bogwasi complete androgen insensitivity syndrome: an ongoing competition regulations, ethics and fairness dilemma c02 dr marcel jooste exertional cardiopulmonary symptoms following viral urti's take it to heart c03 dr jo-anne kirby vertigo in a hockey player c04 dr lervasen pillay pericarditis viral enteritis or covid19 to blame? c05 dr karen schwabe back to basics: spinal pain in a recreational runner c06 dr karen schwabe an unusual case of a femoral bone stress injury in a high school female hockey player scientific abstract presentations o01: similar medial knee contact force measures found in individuals with osteoarthritis and lower limb amputation: a systematic review lizanne andrag1, lovemore kunorozva2, wayne derman2, 3, phoebe runciman2 department of sport science, faculty of medicine and health sciences, stellenbosch university (stellenbosch, south africa)1, institute of sport and exercise medicine (isem), department of sport science, faculty of medicine and health sciences, stellenbosch university (cape town, south africa)2, international olympic committee (ioc) research centre (south africa)3 21008884@sun.ac.za background: osteoarthritis (oa) is a major cause of disability, affecting an estimated 20% of the world population. researchers have found that whilst individuals with unilateral lower limb amputation (ulla) are five times less likely to develop oa in their prosthetic limb, they are 17 times more likely to develop oa in their sound side limb. methodology: researchers systematically searched pubmed-medline, ebscohost and web of science for articles published between jan 1990 and 28 february 2022. studies were included if they investigated the involved side of individuals with oa and/or the uninvolved side of individuals with unilateral lower limb amputation. whilst comparing the biomechanical variables (ground reaction force (grf); external knee adduction moment (kam); external knee adduction moment loading rate (kamlr); external knee adduction moment impulse (kam-imp); knee flexion moment (kfm)) to either the contralateral side or a separate control group. additionally, this study assessed the differences in the loading parameters between the involved side and the uninvolved side of these individuals. results: of the potential 496 eligible articles, 34 articles were included in this review. twenty of the included studies investigated the involved side of an oa population and 14 studies the uninvolved side of an individual with ulla. variables, kam and kfm, increased in both the individuals with ulla and those with oa. for the grf and kam-lr, the oa population tended to show a decrease, while it increased for those with ulla. for individuals with ulla, kam-imp had no known effect but increased in those with oa. conclusion: while a vast amount of research exists on the development of oa in able-bodied individuals, few studies give a clear indication of the development of oa in individuals with ulla. studies often stated that individuals with ulla are more likely to develop oa and present with abnormal ranges of the applicable variables, like in individuals with oa. surrogate measures for contact force in the medial knee (kam and kfm) exhibited the same trends in both population groups. thus, a conclusion may be drawn that individuals with ulla may demonstrate similar biomechanical profiles to individuals with diagnosed oa. mailto:21008884@sun.ac.za o02: management of proximal rectus femoris injuries – do we know what we’re doing?: a systematic review lone bogwasi1, 2, 3, louis holtzhausen1, 4, 5, dina c (christa) janse van rensburg1, 6, audrey jansen van rensburg1, tanita botha7 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa1, caf medical committee member2, botswana football association medical committee member3, aspetar orthopedic and sports medicine hospital, weill-cornell medical college; qatar4, department of exercise and sports sciences, university of the free state, bloemfontein, south africa5, medical board member, world netball, manchester,uk6, department of statistics, faculty of natural and agricultural sciences, university of pretoria, pretoria, south africa7 lonebogwasi@gmail.com background: rectus femoris (rf) injury is a concern in sports. the management of rf strains/tears and avulsion injuries need to be clearly outlined. the purpose of this systematic review is to report the existing best evidence on current management strategies for rf injuries based on the current concepts in management of rf injuries. we ascertained the efficacy of these management strategies as measured by time to return to sport (rts) and re-injury rates. methodology: a systematic review of available literature was conducted using medline via pubmed, worldcat, embase, sportdiscus. eligible studies reporting on the management of rf kicking and sprinting injuries were reviewed. results: thirty-eight studies involving a hundred and fifty-two participants were included. majority (n=138; 91%) were males, 80% (n=121) sustained rf injury from kicking and 20% (n=31) during sprinting. the myotendinous (mt), (n=27); free tendon (ft), (n=34), and anterior-inferior iliac spine (aiis), (n=91) were involved. treatment was conservative (n=115) or surgical (n=37) across the subgroups. the majority of surgical treatments (n=27; 73%) followed, failed conservative treatment. the mean rts was shorter with successful conservative treatment (mt: 1, ft: 4, aiis avulsion: 2.9 months). surgical rts ranged from 2-9 months and 18 months with labral involvement. with either group, there was no reinjury within 24 months of follow-up. conclusion: with low certainty of evidence, rf injury occurs mostly from kicking, resulting in a tear or avulsion at the ft and aiis regions with or without a labral tear. with low certainty, findings suggest that successful conservative treatment provides a shortened rts. surgical treatment remains an option for failed conservative treatment of rf injuries across all injury subgroups. high-level studies are recommended to improve the evidence base for the treatment of this significant injury. mailto:lonebogwasi@gmail.com o03: foot morphology of urban and rural south african children and adolescents marise breet1, ranel venter1 stellenbosch university1 marise@mbio.co.za background: ill-fitting shoes could negatively impact the development of the pediatric foot. this could eventually lead to foot problems and pathologies, both during childhood and adulthood. a substantial number of children and adolescents in south africa were reported to be habitually barefoot. additionally, vast differences have been documented between the foot morphology of south african children and adolescents and their german counterparts. regardless of these findings, shoe companies are still developing shoes on a universal constant. methodology: a cross-sectional, observational, descriptive study design was used to determine the static standing and sitting foot measurements of children and adolescents from both urban and rural schools. the feet of seven-hundred-and-thirty-one school children (n=731) between the ages of six and sixteen years were measured on a once-off basis. newly manufactured school shoes were then measured and compared to the foot measurements of the children. a mixed model anova was used to compare foot dimensions between gender, age and rightor left-side of the participants. results: the results indicated that the rural children and adolescents had a statistically higher sitting static arch height index (p=0.001), than the urban children. there were no statistically significant differences in the standing foot length (fl), standing foot width (fw) and standing static arch height index (sahi) between the feet of children and adolescents from rural and urban areas. comparing the foot measurements of the participants in the study to the shoe dimensions currently available in the south african retail market, fifty-nine percent (59%) of the children wore shoes that were not the correct length. regarding shoe width, ninety-eight percent (98%) of the participants wore shoes too narrow for their feet. conclusion: therefore in many cases, school shoes currently available in the retail market are not adequately suited for the habitually barefoot population studied. factors such as footwear habits and ethnicity could be investigated further. it is recommended that the shoe manufacturing industry consider the shoe width of school shoes for south african children and adolescents, to avoid the longterm adverse effects of ill-fitting shoes on the pediatric foot, specifically in the case of habitually barefoot populations. mailto:marise@mbio.co.za o04: an analyses of twitter-traffic on physical activity-related messaging during the period of south africa’s covid-19 lockdown darren cecil1, johan van heerden1 dpt biokinetics, ukzn, south africa1 darrenjeremycecil@gmail.com background: implementing a lockdown aided in controlling the covid-19 pandemic but simultaneously hindered physical activity, leading to a health decline in many individuals regardless of activity status. social media platforms such as twitter were subsequently employed to communicate public health messages and to promote physical activity participation as a means to boost individuals’ immune systems. accordingly, this study analysed the themes and trends of physical activity-related messaging on twitter-sphere, during the period corresponding with south africa’s covid-19 lockdown. methodology: a content analysis using the pico approach of conducting systematic reviews was utilized. the tweets were collected from south africa’s lockdown level 5 to level 1 (23 march 2020 to 5th november 2020) using 12 physical activity-related terms and/or hashtags (#) with 3 covid-specific hashtags (#covid, #covid19 and #covid_19). sub-set categories of data were summarized as frequencies (n) and relative frequencies, with statistical significance between sets determined using the chi-square statistic with alpha set at p≤0.05. results: a total of 1380 physical activity-related tweets were analysed, with the greatest number posted during lockdown level 5 (n=385; 27.9%) with a decrease (p≤0.0001) thereafter as lockdown levels and their restrictions eased. the majority (p≤0.0001) of messages contained offering intents (96.4%) versus seeking intents (3.6%). information was consistently the most offered subcomponent across all covid lockdown levels. tweets with seeking intents mostly sought responses to questions or surveys. most tweets (p≤0.0001) used text only (59,60%) as opposed to additional media in the form of images (29,5%), video (7,7%) and infographics (3.2%). conclusion: twitter has been a busy channel for the dissemination of physical activity-related information during the covid-pandemic. the frequency of tweets decreased over the duration of the pandemic. most tweets offered information in the form of simple text messages and images rather than seeking responses. this provides an understanding of the nature of physical activity-related tweeting over the covid-19 lockdown period and insight in the face of potential future public health crises. mailto:darrenjeremycecil@gmail.com o05: prevalence and correlates of adherence to total physical activity guidelines using step-counting in pre-school children: the sunrise study tawonga w. mwase-vuma1, xanne janssen1, kar hau chong2, mark s. tremblay3, amanda e. staiano4, anthony d okely2, catherine e. draper5, nyaradzai munambah6, penny cross2, john j. reilly2 university of strathclyde, glasgow, uk1, university of wollongong, wollongong, new south wales, australia2, cheo research institute, ottawa, canada3, louisiana state university, louisiana, us4, university of the witwatersrand, johannesburg, south africa5, university of zimbabwe, harare, zimbabwe6 tawonga.mwase-vuma@strath.ac.uk background: evidence suggests that the de creamer threshold of 11,500 steps/day is valid and internationally suitable for surveillance of the who recommendation that young children should spend at least 3 hours per day in total physical activity (tpa). however, there are limited studies on the prevalence and correlates of adherence to this guideline. therefore, we examined the prevalence and identified correlates of adhering to the step-based tpa guideline using the de craemer step count threshold of 11,500 steps/day in a geographically and culturally diverse sample of pre-school children. methodology: this study included 797 pre-school children (49.2% girls, mean age 4.4 years) from 17 middleand high-income countries who participated in the sunrise international pilot study. steps/day were measured using activpal accelerometers which children wore on the thigh for at least three days. children were classified as meeting or not meeting the step-based tpa guideline of 11,500 steps/day. logistic regression was used to identify potential socio-demographic correlates of meeting the stepbased tpa guideline using the forward selection method. these included sex, age, parent/caregiver education class, residential area, and country income level. results: overall, 30.9% of the pre-schoolers met the step-based tpa threshold of at least 11,500 steps/day. the prevalence was higher among boys (34.3%) than girls (27.3%). the odds of meeting the step-based tpa threshold were significantly lower among girls (or: 0.48; 95% ci: 0.31, 0.73) and 4-yearolds (or: 0.36; 95% ci: 0.22, 0.58) vs. 3-year-olds. the odds of meeting the threshold were significantly higher among children from rural areas (or: 2.28; 95% ci: 1.47, 3.54) vs. urban areas and lower-middle income countries (or: 2.10; 95% ci: 1.27, 3.45) vs. high-income countries. parent/caregiver education level was not associated with meeting the step-based tpa threshold in the adjusted model (or: 2.19; 95% ci: 0.99, 2.47). conclusion: few pre-school children in this diverse global sample met the step count threshold that aligns with the who tpa guideline. meeting the guideline was more prevalent among the younger children, boys, and children residing in rural areas and in lower-middle income countries. mailto:tawonga.mwase-vuma@strath.ac.uk o06: disease burden of soil transmitted helminth infections on cardiovascular disease risk, physical activity and fitness in primary school children in port elizabeth, south africa siphesihle nqweniso1, cheryl walter1, markus gerber2, rosa du randt1, johanna beckmann2, jean coulibaly3, 4, 5, kurt z. long2, 3, harald seelig2, jürg utzinger2, 3, christin lang2, 3 department of human movement science, nelson mandela university, port elizabeth, south africa1, department of sport, exercise and health, university of basel, basel, switzerland2, swiss tropical and public health institute, basel, switzerland3, centre suisse de recherches scientifiques en côte d’ivoire, abidjan, côte d’ivoire4, unité de formation et de recherche biosciences, université félix houphouët-boigny, abidjan, côte d’ivoire5 felicitas.nqweniso@mandela.ac.za (abstract withdrawn) mailto:felicitas.nqweniso@mandela.ac.za o07: the epidemiology of lower limb injuries during the super rugby tournaments (2013-2016) involving 76301 player-hours clement plaatjies1, 2, audrey jansen van rensburg2, martin schwellnus2, 3, 4, christa janse van rensburg1, charl janse van rensburg5, esme jordaan6 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa1, sport exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa2, emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa3, international olympic committee (ioc) research centre, south africa4, biostatistics unit, south african medical research council, south africa5, statistics and population studies department, university of the western cape6 clementplaatjies@yahoo.com background: rugby union involves frequent high-impact collisions and tackles and has a high injury rate. the aim was to determine the incidence, nature (player position, anatomical body area, tissue type), severity (% time loss, injury burden), mechanism of injury (contact vs. non-contact), and phase of play of lower limb injuries (lli) sustained by rugby players during the super rugby tournaments. methodology: a cross-sectional analysis studied 868 male professional rugby union players from all south african teams participating in the super rugby tournament (2013–2016). team physicians recorded all lli (all training and match lli) daily. injury exposure was 76301 total player-hours, including 6520 match player-hours. numbers, proportions, incidence (i: per 1000 player-hours; 95% ci), and lli burden (days lost due to lli per 1000 player-hours) are reported. results: throughout the 4-years, a total count of 776 injuries occurred. lli attributed to 422 (54.4%) of all training and match injuries with an overall incidence of 5.3 (4.9-5.8). llimatch injuries (llimatch, n=346) contributed 51.2% to the total match injuries (n=676) with an incidence of 53.1 (47.6-59.0). the incidence of llimatch injuries in backline players (52.6; 45.5-60.4) compared to forwards (46.9; 40.753.9) were similar (p>0.05). in match-play, the thigh (27.5%) and knee (24.0%) were the most commonly affected anatomical body area. muscle/tendon injuries comprised 57.8% of all llimatch injuries, and joint/ligament injuries of 35.3%. most match injuries occurred in contact (61.0%), and during a tackle situation (42.2%). the majority of llimatch injuries were of minimal to mild severity (2-7 days; 60%). the injury burden of llimatch injuries was 1126 (1100-1152) days lost. conclusion: lli are the most common injury sustained by male super rugby players, especially during match-play (51.2%). the thigh and knee are the most frequent lower limb area injured. most lli during matches are muscle and tendon injuries and are of minimal to moderate severity. the most significant contributor to llimatch injury is contact and the tackle situation. these findings are important for designing and implementing lli prevention strategies in rugby players. mailto:clementplaatjies@yahoo.com o08: physical activity, fitness and visual attention in young adults with depressive symptoms sarah j moss1, l enslin1, a kruger2, s.h. czyz3 phasrec, north-west university, potchefstroom1, chhp, north-west university, potchefstroom2, phasrec, north-west university, potchefstroom and faculty of physical education and sport, university school of physical education, wrocław, poland3 hanlie.moss@nwu.ac.za background: the management of mental health in young south african adults is a health priority. like the global trends, mental health, including major depression, is increasing among young adults. inverse associations are reported between depression scores and screen time, but the association with visual attention, as determined with multiple object tracking (mot) task, have not been investigated. this study aims to determine the associations between depressive symptom score, physical activity, fitness level, screen time and mot in young south african adults with depressive symptoms. methodology: baseline preliminary data from 30 young adults aged 18 – 25 years enrolled in the depression exercise intervention study were analysed. the beck depression inventory (bdi) was used to screen for depressive symptoms among the participants. physical measurements of body composition, objective physical activity (actiheart) and fitness were assessed. cortisol was measured from blood samples and visual attention with mot (neuro tracker). associations between the variables were determined with pearson correlation analyses. results: participants (aged 21 ± 2 years) had an average bdi-score of 19.8 ± 9.1 and an average body fat percentage of 30 ± 12%. less than 80 minutes per week was spent in moderate-to-vigorous physical activity, and the predicted fitness was 35.1 ± 6.5 ml/kg/min. mot response time was 8.15 ± 1.29 sec. significant correlations were found between the bdi score and leisure screentime (r = 0.512; p =0,005), as well as bdi score and mot total time (r= -0.529; p = 0.007). conclusion: this study concludes that persons reporting high screen time during leisure also scored higher for depressive symptoms. higher depressive symptoms scores were correlated with lower visual attention total time. although a causal effect cannot be determined, understanding the relationships between screen time, visual attention, fitness and depressive symptoms will assist in developing intervention strategies for the management of depressive symptoms in young adults. mailto:hanlie.moss@nwu.ac.za o09: mental health profiles of healthcare professionals working during the tokyo 2020 and beijing 2022 paralympic games maaike eken1, phoebe runciman1, marelise badenhorst2, leslie swartz3, vincent gouttebarge4, 5, cheri blauwet6, wayne derman1, 7 institute of sport and exercise medicine (isem), department of sport science, faculty of medicine and health sciences, stellenbosch university, cape town, south africa1, ports performance research institute new zealand (sprinz), auckland university of technology, auckland, new zealand2, department of psychology, stellenbosch university, stellenbosch, south africa3, department of orthopaedic surgery, amsterdam movement sciences, amsterdam umc, university of amsterdam, amsterdam, netherlands4, section sports medicine, university of pretoria, pretoria, south africa5, department of physical medicine and rehabilitation, spaulding rehabilitation hospital and brigham and women’s hospital, harvard medical school, boston, massachusetts, usa6, international olympic committee research centre, south africa7 meken@sun.ac.za background: during the paralympic games, healthcare professionals (hcps) play an important role in managing athletes’ health. hcps are however required to work long hours, and stress and exhaustion are not uncommon during games time. these factors could contribute to adverse mental health of hcps who treat para athletes during games, which could influence the (mental) health of the athletes. the aim of this study is to describe mental health profiles of hcps in the paralympic setting. methodology: hcps working during the tokyo 2020 and beijing 2022 paralympic games were asked to complete an online, anonymous survey, which included demographic questions and questions regarding self-reported mental health symptoms including depression (phq-9), anxiety (gad-7) and burn-out (mbi/hss: depersonalisation (dp), emotional exhaustion (ee), personal accomplishment (pa)). frequency analyses were used to describe demographic characteristics and mental health symptoms. spearman’s rho was calculated to investigate correlations between demographic characteristics and mental health symptom scores. results: in total, 256 hcps (of approximately 500 hcps) completed the surveys, of which 212 were from tokyo and 44 beijing. the majority of hcps practiced medicine (56%), were more than 10 years involved in management of athlete health (52%) and from a high-income economy country (46%). most hcps reported minimal (72%) or mild (16%) depressive symptoms and minimal (72%) or mild anxiety related symptoms (19%), while more than 30% reported moderate to high burnout (dp: 35%; ee: 35%; pa: 56%). yet, severe symptoms and thoughts of self-harm were reported by some hcps. weak correlations were observed between age and depression (rho=-0.13, p=0.046), anxiety (rho=-0.16, p=0.010) and aspects of burnout (ee: rho=-0.14, p=0.032; pa: rho=0.27, p<0.001) scores, indicating that symptoms of depression, anxiety and burnout were more reported by younger hcps. conclusion: most hcps working during the tokyo 2020 and beijing 2022 paralympic games reported minor mental health symptoms, yet some concerning reports were noted. findings suggested also that symptoms of depression, anxiety and burnout could be more prevalent among younger hcps. teams that are travelling to paralympic games (or other major tournaments) are therefore advised to provide guidance and mental health support of young(er) hcps travelling with the team. mailto:meken@sun.ac.za o10: african big-5 sport psychological assessment tool: development and preliminary validation heinrich grobbelaar1 division of sport science, department of sport science, faculty of medicine and health sciences, stellenbosch university1 hgrobbelaar@sun.ac.za background: the assessment of psychological skills, techniques and methods through valid and reliable self-report instruments are important for sport psychology consultants, both from a theoretical and applied perspective. the study aimed to determine the psychometric properties of wheaton’s (1998) psychological skills inventory (psi). due to poor confirmatory factor analysis (cfa) results on 1610 data entries, the follow-up aim was to develop and validate a new tool to assess sport psychological skills and mental states of athletes. methodology: the dataset was randomly split-in-half, yielding a train and test set with 805 data entries each. an exploratory factor analysis (efa) on the train data suggested a five-factor assessment tool. items that loaded (> 0.40) onto the five subscales were screened. two cfas followed on the train and test sets respectively, to test the goodness-of-fit of the 40-item instrument. results: both cfas demonstrated acceptable goodness-of-fit, item and construct reliability, standardised estimates, and extracted variance results. the five subscales were matched to the african big-5 animal that represented it best: freedom from competition worries (buffalo), goal setting (leopard), visualisation (elephant), competition confidence (lion), and competition concentration (rhino). conclusion: the study demonstrated preliminary evidence in support of the african big-5 sport psychological assessment tool’s (big-5 spat) validity and reliability. future studies should cross-validate the instrument, determine its discriminant and convergent validity and usefulness in applied settings, translate it into other indigenous african languages, and develop normative data. mailto:hgrobbelaar@sun.ac.za o11: correlations between frequency of participation in campus recreation, leisure boredom, and satisfaction with life of undergraduate students theron weilbach1, nadine labuschagne1, theron weilbach1, cornelia schreck1 phasrec, nwu1 theron.weilbach@nwu.ac.za background: emerging adulthood is a challenging life stage and distress, loneliness, and even disengagement in their academic career can hinder students’ transition from high school to university, and consequently affect their entire university experience. however, campus recreation (cr) can play a significant role in the transition from school to university. the purpose of this study was to determine the correlation between the frequency of participation in cr, leisure boredom, and satisfaction with the life of undergraduate students of the north-west university. methodology: a once-off, cross-sectional research design, with a quantitative approach was used. in total, 581 students (48% males; 52% females) completed an online survey which included demographic information, frequency of participation, the format in which each activity is presented, the satisfaction with life scale by diener et al. (1985), and leisure boredom items from the leisure experience battery for young adults by barnett, (2005). results: activities participated in were grouped into six different categories, namely main university sports, additional university sports, group sports, outdoor activities, dance, and exercise. spearman correlation coefficients were used to determine the relationships between different variables. in terms of relationships between leisure boredom and satisfaction with life, a negative statistically significant correlation (r=-.170, p=0.000) exists. total participation in cr had a significant positive correlation with satisfaction with life (r=0.135, p=0.001), and a significant negative correlation with leisure boredom (r=0.146, p=0.000). in terms of correlations between participation in specific categories of cr, satisfaction with life, and leisure boredom, the following was revealed: statistical significant correlations exist between satisfaction with life and additional sport codes (r=.0.90, p=0.029), outdoor sports (r=0.143, p=0.001), and exercise sport (r=0.99; p=0.017). additionally, statistically significant negative correlations were found between leisure boredom and additional sport codes (r=-0.095, p=0.022), group sports (r=.0.089, p=0.032), dance (r=-0.085, p=0.040), outdoor sports (r=-.149, p=0.000) and exercise sports (r=0.099, p=0.017). conclusion: the findings show the importance of cr during students’ time at university. it also gives insight to recreation professionals on which programme areas may benefit students the most. mailto:theron.weilbach@nwu.ac.za o12: prevalence of the relative age effect among high performance, university athletes, versus an age-matched student cohort sindiso dube1, heinrich grobbelaar1 division of sport science, department of sport science, faculty of medicine and health sciences, stellenbosch university1 20075073@sun.ac.za background: relative age effect (rae) refers to the over-representation of athletes born earlier in the calendar year. the rae is especially prevalent in youth sport, but often persists into senior competitive levels. the aim was to determine the prevalence and magnitude of the rae among student-athletes in a high-performance (hp) programme at a south african university, according to year, sport code and sex, compared, to the general student cohort. design: cross-sectional descriptive analysis of hp-student-athletes and an age-matched student cohort from 2016 to 2021. methods: birthdate data was extracted for the hp student-athletes (n = 950: men = 644, women = 306) and student comparison group (n = 47 068; men = 20 464; women = 26 591; not disclosed = 13). differences were determined using chi-squared and fisher’s exact test. residuals examined relative age quartile differences. the steps were applied across academic years, sport code and sex. results: the rae was more pronounced among the student-athletes compared to the age-matched student cohort and seems to become more apparent with each passing year. when analysing the different sport codes, raes were observed for swimming, rugby union and cricket. no sex differences were observed among the hp-student-athletes. conclusions: selection bias favoured the relatively older student-athletes. the mechanisms for rae are multifactorial and complex. a combination of factors, such as competition depth, the popularity and physicality of a sport and socialization may be involved. mailto:20075073@sun.ac.za o13: impact of biological maturity status on talented and non-talented male zimbabwean under-14 footballers joseph syakhuluma sibindi1, heather morris-eyton1, charl roux1 university of johannesburg1 josesibindi@gmail.com background: the study aimed to examine the impact of biological maturity status on identified talented and non-talented male zimbabwean under-14 footballers. currently, the associated differences and impact of biological maturity status on talent identification and selection of youth footballers are unclear. methodology: a total of 141 under-14 footballers were purposively sampled from the bulawayo metropolitan and matabeleland north provinces. the observational and field test methods were used. the non-hierarchical k-means cluster analysis classified 87 footballers as talented and 54 as nontalented using technical football skills tests. results: the mean scores for the talented group were as follows: chronological age (ca) (12.075 ± 0.838), age at peak height velocity (aphv) (14.591 ± 0.558) and maturity offset (-2.614 ± 0.532) while the reported mean scores for the non-talented group were ca (11.914 ± 0.945), aphv (14.597 ± 0.283) and maturity offset (-2.614 ± 0.565). footballers were further classified as early maturers (16.7%), normal maturers (67.9%) and late maturers 15.5% for the talented group. the non-talented group had 21.1% (early), 59.6% (normal) and 19.3% late maturers. hochberg or dunnett’s test indicated no differences among the early, normal and late maturers for the talented and non-talented groups (p > 0.05). there were significant differences between early and late maturers for selected anthropometric data and the shuttle dribble sprint test for the talented group (p < 0.05). in the non-talented group, the early, normal and late maturers showed significant differences for percentage body fat from the triceps and similarly for the late maturers compared with both the early and normal for the distance covered in the yo-yo test. the late maturers in both groups had the fastest shuttle dribble sprint times and lower percentage body fat from the triceps skinfold. conclusion: a normal distribution was observed for the talented and non-talented groups among the early maturers, normal maturers and late maturers. overall, the differences among variables suggested that the maturity status had little or no influence in the talent identification and selection of under-14 footballers. however, practitioners need to identify and select youth footballers based on their potential. mailto:josesibindi@gmail.com o14: patellofemoral pain syndrome (pfps) is associated with chronic disease and allergies in 60 997 distance runner race entrants: a safer study tsungai marandure 1, 2, martin p. schwellnus2, catharina grant1, audrey jansen van rensburg 1, esmè jordaan3, 4, pieter boer5 section sports medicine, faculty of health sciences, university of pretoria, south africa1, sport, exercise medicine and lifestyle institute (semli) pretoria, south africa2, biostatistics unit, south african medical research council, south africa3, statistics and population studies department, university of the western cape, south africa4, department of human movement science, cape peninsula university of technology, south africa5 marandure.md@gmail.com background: patellofemoral pain syndrome (pfps) is a common gradual onset running-related injury with multiple risk factors. this descriptive cross-sectional study aims to identify the risk factors associated with pfps in distance runners that entered the 21.1km and 56km two oceans marathon races (2012-2015). methodology: a pre-race medical screening questionnaire was completed by 106 743 race entrants, 76 654 participants (71.8%) consented to the study. the study population (n=60 997) consisted of 362 race entrants reporting a history of pfps in the previous 12 months, and 60 635 runners with no injury history. pfps was verified by a health care professional in the injured group. risk factors associated with pfps were explored using uni& multiple regression analyses: demographics (age groups, sex, and race distance), training/running variables, history of existing chronic diseases (including a composite chronic disease score) and any allergy history. prevalence (%, 95%ci) and prevalence ratios (pr) are reported. results: the period (12 month) prevalence of pfps was 0.5% (0.43-0.54). independent risk factors associated with a history of pfps (adjusted for age, sex and race distance) were a higher chronic disease composite score (pr=2.7 times increased risk for every 2 additional chronic diseases; p<0.0001), and a history of any allergies (pr=2.3; p<0.0001). chronic diseases (pr>2; univariate analysis) associated with a history of pfps were: gastrointestinal disease (pr=5.1; p<0.0001), risk factor for cardiovascular disease (cvd) (pr=3.3; p<0.0001), nervous system/psychiatric disease (pr=3.0; p<0.0001), cancer (pr=2.8; p=0.0005), risk factors for cvd (pr=2.4; p<0.0001), symptoms of cvd (pr=2.4; p=0.0397) and respiratory disease (pr=2.0; p<0.0001). an increased number of years of recreational running (pr=1.1; p=0.0107) and older age (>50 years) were also associated with a higher risk of pfps. conclusion: the novel independent risk factors associated with a history of pfps in distance runners (21.1km, 56km) are multiple chronic diseases and a history of any allergies. a medical evaluation to identify runners with chronic diseases may be considered a specific injury prevention strategy to reduce the risk of pfps. mailto:marandure.md@gmail.com o15: an abbreviated vs. a comprehensive pre-race medical screening tool underestimates runners at higher risk of medical encounters – a safer study in 5771 race entrants jordan leppan1, 2, martin schwellnus2, 3, nicola sewry2, 3, jeremy boulter4, christa janse van rensburg1, marlise dyer1, esme jordaan5, 6 section sports medicine, faculty of health sciences, university of pretoria1, sport, exercise medicine and lifestyle institute (semli), university of pretoria2, ioc research centre, pretoria, south africa3, comrades marathon, pietermaritzburg4, biostatistics unit, south african medical research council (samrc)5, statistics and population studies, university of the western cape6 jordanleppan@gmail.com background: the comrades marathon has, for many years, obtained medical information from participants through an abbreviated pre-race screening tool consisting of two open-ended medical questions. it is unknown how this abbreviated screening compares to full pre-race medical screening tools. the aim of the study was to determine if two pre-race screening tools (abbreviated tool of two open-ended pre-race medical screening questions [abbr] vs. a full pre-race medical screening tool [full]) identify the same number of running race entrants at higher risk for medical encounters (mes)based on the identification of: 1) allergies 2) medical conditions and/or prescription medication use. methodology: data from 5771 consenting race entrants who completed both the abbr and the full pre-race screening questionnaires for the 2018 comrades marathon were collected. the two abbr questions were 1) allergies, and 2) known medical conditions and/or prescription medication use in free text. the full tool included multiple domains of questions for various diseases (including cardiovascular disease (cvd) symptoms and risk factors), running injuries, allergies and medication use. responses to the abbr were manually coded in similar domains of questions as in the full and compared to the full, and further risk stratified into “very high-risk”, “high risk”, intermediate risk” and “low risk” of having a medical encounter during the race (based on pre-existing medical conditions). the prevalence (%: 95%ci), and the test for equality of prevalence (with p-value) of entrants identified by the abbr vs. full are reported. results: the abbr identified fewer entrants with allergies (abbr=7.9%; full=10.4%: p=0.0001) and medical conditions/medication use (abbr=8.9%; full=27.4%: p=0.0001). the full stratified many more entrants in the “high risk” (12.4%) and “very high-risk” (3.4%) categories compared with the abbr (3.36% and 0.5% respectively) (p=0.0001). the abbr also over-estimated the number of entrants in the “low risk” category (63.4%) compared to the full (46.5%). conclusion: the abbr significantly under-reported for allergies, specific medical conditions/medication use and risk profile of the entrants compared with the full. this level of under-reporting will lead to a false prediction of mes on race day. mailto:jordanleppan@gmail.com o16: development of a trail running injury screening instrument: a multiple methods approach carel viljoen1, 2, 3, christa janse van rensburg4, willem van mechelen2, 5, 6, 7, evert verhagen2, elzette korkie8, tanita botha9 department of physiotherapy, faculty of health sciences, university of pretoria, pretoria, south africa1, amsterdam collaboration for health and safety in sports, department of public and occupational health, amsterdam movement sciences, amsterdam university medical centers, location vu university medical center, amsterdam, the netherlands2, sport, exercise medicine and lifestyle institute (semli), pretoria, south africa3, section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa4, school of human movement and nutrition sciences, faculty of health and behavioural sciences, university of queensland, brisbane, australia5, division of exercise science and sports medicine (essm), department of human biology, faculty of health sciences, university of cape town, south africa6, school of public health, physiotherapy and population sciences, university college dublin, dublin, ireland7, department of physiotherapy, faculty of health sciences, university of pretoria, pretoria, south africa8, department of statistics, faculty of natural and agricultural sciences, university of pretoria, pretoria, south africa9 carel.viljoen@up.ac.za background: trail running has a high risk for injury and medical support is challenging in remote regions. injury risk management in trail running is of importance, but limited literature is available in the field. therefore, the need to make use of expert opinion to guide current injury risk management in trail running. methodology: the study utilised five phases in a multiple methods approach 1) identification of injury risk factors 2) determining the relevance of each identified risk factor in a trail running context, 3) creating the content of the likert scale points from 0 to 4, with each point indicating an increase in injury risk for each selected injury risk factor, 4) rescaling the likert scale points to determine numerical values for the content of each likert scale point, and 5) determining a weighted score for each injury risk factor that contributes to the overall combined composite score. results: seventy-seven injury risk factors were identified of which 26 risk factors were deemed relevant in trail running. the weighted score for each injury risk factor ranged from 2.21 to 5.53. the highest calculated scores were 5.53 (buying running shoes based on a running analysis and not primarily based on a good shoe fit), followed by 5.41 (not adhering to a specific running-related, supervised training plan), and 5.11 (competitive training). the final trisi includes risk categories of training, running equipment, demographics, previous injury, behavioural, psychological, nutrition, chronic disease, physiological, and biomechanical factors conclusion: the developed trisi aims to assist the clinician during pre-race injury screening or during a training season to identify meaningful areas to target in designing injury risk management strategies and/or continuous health education mailto:carel.viljoen@up.ac.za o17: five international pre-exercise medical screening tools vary greatly regarding their identification of running race entrants who require medical clearance: a safer study chanel smith1, kim nolte1, martin schwellnus1, 2, 3, nicola sewry1, sonja swanevelder4, esme jordaan4, 5 sport, exercise medicine and lifestyle institute (semli) and division of biokinetics and sports science, department of physiology, faculty of health sciences, university of pretoria, south africa1, international olympic committee (ioc) research centre, south africa2, emeritus professor, faculty of health sciences, university of cape town, south africa3, biostatistics unit, south african medical research council4, statistics and population studies department, university of the western cape5 chanel.nel.smith@gmail.com background: the purpose of pre-exercise medical screening is to identify individuals who may be at risk of medical encounters (mes) during exercise. currently five international pre-exercise medical screening tools are recommended to identify individuals who require pre-exercise medical clearance. the aim of this study was to determine the percentage of race entrants who are advised to obtain pre-exercise medical clearance by using five international pre-exercise medical screening tools, and to determine the level of agreement between those tools. methodology: data from running race entrants (two oceans marathon) were collected over a period of four years (2012–2015). five pre-exercise medical screening tools (the american heart association (aha), the pre-2015 american college of sports medicine (acsm), the post-2015 acsm, the canadian physical activity readiness questionnaire (par-q), and the european association of cardiovascular prevention and rehabilitation (eacpr)) were applied by using information from pre-race medical screening questionnaires. the primary measure of outcome was the % (95%ci) of race entrants for whom pre-exercise medical clearance was recommended using each of the five international preexercise medical screening tools. a secondary measure was the level of agreement (kappa test) between the results obtained by using different tools. results: the percentage entrants requiring medical clearance for each tool was as follows: 2011 eacpr (33.9%; 33.5-34.3); pre-2015 acsm (33.9%; 33.5-34.3); par-q (23.2%; 22.9-23.6); aha (10.0%; 9.7-10.2); post-2015 acsm (6.7%; 6.5-6.9). the level of agreement was high between the pre-2015 acsm and the eacpr (k=1.00; p=0.05), moderate between the pre-2015 acsm and the par-q (k=0.75; p<0.0001) and the par-q and eacpr (k=0.75; p<0.0001), but poor between the post-2015 acsm and the par-q (k=0.17; p<0.0001). conclusion: five international pre-exercise medical screening tools vary greatly regarding their identification of race entrants identified requiring medical clearance (6.7–33.9%). the level of agreement between the tools also varied and was good (> 0.75) for three of the five pre-exercise medical screening tools. further research should determine which specific variables identify participants at higher risk for medical encounters during exercise. mailto:chanel.nel.smith@gmail.com o18: the prevalence of mental health disorders among semi-professional cricketers residing in the western cape lesego malele1, habib noorbhai1 department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa1 shaz.malele.sm@gmail.com background: cricket requires high cognitive function for optimum performance. due to covid-19, it is even more paramount that mental health of athletes is monitored. the existing epidemiology studies among cricket players are equivocal; and as a result, the prevalence and long-term effects of mental health disorders is unknown. the aim of this research study was to investigate the prevalence of mental health disorders among semi-professional cricketers (provincial b and university squads) and how it affects their well-being. methodology: this was an epidemiological, cross-sectional study design. the study was conducted among semi-professional (provincial b and university squads) cricket players (n = 63) residing in the western cape. among the sample, descriptive statistics including means and standard deviations were calculated. mental health screening among cricketers was assessed with the depression, anxiety and stress scale – 21, (dass – 21), the satisfaction with life scale (swls) and athlete burnout questionnaire. results: the dass – 21 subscales are depression (m = 9.90, sd = 9.36), which translated mild depression. anxiety (m = 10.67, sd = 9.60) was translated to moderate anxiety and stress (m = 14.73, sd = 9.85) means that most players fell within the mild stress category. the swls (m = 27.71, sd = 6.61) means that the players are slightly satisfied; but there are areas requiring improvement. the athlete burnout subscales are physical and emotional exhaustion (rarely; m = 23.2, sd = 3.90); devaluation of sport practice (almost never; m = 29.2, sd = 6.61) and reduced sense of achievement (sometimes; m = 23.4, sd = 2.97). conclusion: the results depicts that some players require mental health investigation, as it is paramount for their performance. burnout, mental health as well as life satisfaction plays a vital role in an athlete being successful. cricket south africa would improve holistically if mental health monitoring of cricketers are integrated in their existing systems, which can indirectly provide better performance management of players. since there is limited evidence on the psychological effects on performance among cricketers at an amateur and professional level, future studies should widen investigations of mental health disorders among varied skilled levels. mailto:shaz.malele.sm@gmail.com o19: the relationship between tackle technique measured in training and matches steve den hollander1, 2, mike lambert1, ben jones1, 3, 4, sharief hendricks1, 3, 4 research centre for health through physical activity, lifestyle and sport (hpals), dept of human biology, faculty of health sciences, university of cape town1, uxi sport2, carr3, leeds beckett university4 steve_dh1989@hotmail.com background: contact (tackle, ball-carry, and ruck) technique is associated with measures of performance and injury outcomes in rugby matches and training. yet, little is known about the relationship between contact technique assessed in training and matches, or the transference of a player’s technique proficiency in training into matches. this study aimed to describe the relationship between contact technique in training and matches, and measures of performance. methodology: twenty-four male players, from an amateur rugby club, participated in the study. at the beginning of the season, players’ contact technique proficiency was assessed in a training drill. contact technique in matches was assessed during 14 competitive league matches. the technique proficiency was assessed using standardised criteria, and the outcomes of each tackle, ball-carry and ruck were recorded. a one-way analysis of variance, cohen's effect sizes and linear regression analyses were used. results: higher contact technique scores were associated with positive performance outcomes in training and in matches. for instance, the tackle technique was significantly lower in missed, compared to ineffective, tackles in training (p<0.05, es=0.8) and matches (p<0.05, es=1.2). players’ contact technique scores in matches also had a positive effect on their match performance. ball-carry technique was associated with tackle breaks made per game (p<0.05, r2 = 0.31). however, contact technique scores in training did not affect match performance. contact technique scores were also lower in matches compared to training, with a 13.3% difference in means between ruck technique assessed in training and matches (p<0.01, es=0.8). we found a large variation in the percentage of a player’s training technique represented in their match technique, with tackle technique ranging from 68%-100%. conclusion: the findings of this study demonstrate the validity of assessing contact technique in training, as technique proficiency led to the same outcomes in the tackle, ball-carry, and ruck, in training and matches. the differences in technique between training and matches indicate that the drill may be too structured to fully represent the open nature of the tackle and ruck contests. these findings highlight the importance of contact skill training, in environments of varying structures, to ensure skills developed in training are transferred to match performance. mailto:steve_dh1989@hotmail.com o20: soccer players' perception of soccer boot comfort a study to investigate soccer boots' suitability to soccer players' foot morphology simiso ntuli1, heather morris-eyton1, andrew green1 university of johannesburg1 sntuli@uj.ac.za background: the foot is a complex structure used for locomotion, which has great malleability and susceptibility to internal and external factors. it must be rigid to carry bodyweight with appropriate stability and must interact and adapt to all ground conditions; therefore, it must be flexible to support the body during static and dynamic tasks. a soccer boot is the most crucial piece of equipment for soccer players that has two primary functions, performance enhancement and injury prevention. additionally, it acts as an interface between the player's foot and the playing surface as well as between the player's foot and the ball. foot morphology and boot match should be considered significant in the provision of soccer injury prevention strategies. however, few studies have investigated the soccer boot's suitability to the foot type of the intended user. the aim of this study was to investigate soccer players’ foot morphology and the suitability of soccer boots. methodology: a cross-sectional design study in which data were collected from professional and university soccer players. data were collected in two phases. phase one included the completion of an adapted questionnaire to collect data on player demographic data including areas of pain or discomfort with the boot. phase two involved scanning each participant's feet using a 3d scanner to determine each player’s foot morphology and measurements. data were analysed using descriptive statistics with a pvalue set at < 0.05 for statistical significance. results: data were collected from professional (n=127) and university (n=62) male soccer players. the mean age was 25.09 and 20.21years respectively, with mean playing years reported at 6.75 and 2.71. most players (92%) reported areas of discomfort and reduced fitting with their current boot. players identified the toe box (94%), arch area (77%) and boot length (18%) as areas of pain or irritation. the 3d measurements revealed variations in arch heights, forefoot width and hallux toe flexion angles. conclusion: there is evidence that players experience discomfort with their current soccer boots. this could be due to a disjuncture between foot type and boot fit. foot morphology is an important consideration when selecting a soccer boot to match the individual foot type. considering foot morphology during boot selection will improve the boots' two primary functions, performance enhancement and injury prevention mailto:sntuli@uj.ac.za o21: index of coordination of running in triathletes katelyne van den bergh1, ryan raffan1 nelson mandela univeristy1 katiemvdb@gmail.com background: motor organization in swimming has been measured using the index of coordination (idc). however, the idc has not been utilized to analyse other cyclic actions such as running. this study aimed at investigating the idc of running in triathletes. methodology: sixteen male triathletes participated in two consecutive, self-paced 5000m shuttle run trials, with full recovery between trials. the trials were video recorded but only the fastest trial was coded frame-by-frame to determine the time markers of heel strike and toe-off for both legs, and used to calculate idc. the idc was calculated for each of the three portions of the 5000m trial (1650m, 1650m and 1700m). backward stepwise multiple regression was performed. the group was dichotomized into a fast and slow running group using the median split technique and a t-test was used to determine significance between groups. results: the results revealed that 48% of the fastest trial run time can be explained by the idc obtained in portion three (p=0.003). furthermore, the slower running group had a significantly lower idc in portion one (p=0.033) whereas the faster running group had a significantly lower idc in portion three (p=0.008). conclusion: these findings suggest that the movement system of the faster running group was able to produce better adaptive responses as they progressed through the 5000m, demonstrating a more efficient and economical organizational mode. in contrast, the movement system of the slower running group struggled to adapt to the task demands as they progressed through the 5000m, particularly in the later part of the task, resulting in significant increases in idc and a more inefficient mode of coordination. the idc should be utilized as a performance tool, in conjunction with other performance parameters, to help identify motor organization and inefficiencies. lastly, investigating the influence of motor synchronization devices on the emergence of more adaptive and efficient motor responses may be worthwhile. mailto:katiemvdb@gmail.com o22: the effect of tibialis anterior weakness on foot drop and toe clearance in patients with facioscapulohumeral dystrophy clement n. gambelli1,2, 3, jonathan bredin2, 4, aude-clemence m. doix2, jeremy garcia5, veronique tanant5, manuella fournier-mehouas2, 5, claude desnuelle6, sabrina sacconi6, 7, serge s. colson2 physical activity, sport and recreation research focus area (phasrec), potchefstroom campus, northwest university (nwu), potchefstroom, south africa1, université côte d’azur, lamhess, france2, laboratory of physiology and biomechanics of locomotion, institute of neuroscience (ions), universite catholique de louvain (ucl), louvain-la-neuve, belgium3, centre de santé institut rossetti-pep06, nice, france4, université côte d’azur, chu, france5, université côte d’azur, cnrs, inserm, ibv, france6, université côte d’azur, chu, cnrs, inserm, ircan, france7 40808742@nwu.ac.za background: facioscapulohumeral dystrophy (fshd) is a genetic disease characterized by progressive muscle weakness leading to a complex combination of postural instability, foot drop during swing and compensatory strategies during gait that have been related to an increased risk of fall. the aim is to assess the effect of tibialis anterior muscle (ta) weakness on foot drop and minimum toe clearance (mtc), as well as the compensatory strategies of fshd patients during gait. methodology: eight fshd patients allocated to a subgroup depending on their ta weakness assessed by manual muscle testing (i.e., fshd<3 and fshd>3) and 8 matched healthy control participants were equipped with retro-reflective markers to record the kinematics of walking at self-selected speed with a motion analysis system. results: walking speed (for both fshd<3 and fshd>3) and step length (for fshd<3 only) were significantly decreased in fshd patients whereas mtc central tendency was similar across all fshd patients and control participants. a greater foot drop was systematically observed for fshd<3 during swing and only in late swing for fshd>3.. in addition, mtc variability was increased only for fshd<3. individual strategies to compensate for foot drop remains unclear and may depend on other muscle impairment variability. conclusion: the reduced walking speed for all fshd patients seems to be a compensatory strategy to maintain balance although trunk instability and foot drop at foot strike. the more precautious gait in patients with severe ta weakness, i.e. reduced step length, seems to be an adaptation to enhanced foot drop. increased mtc variability in fshd patients with severe ta weakness suggests an increased risk of tripping. manual muscle testing is a simple and effective method to assess ta weakness and seems to identify fshd patients at an increased risk of tripping. mailto:40808742@nwu.ac.za o23: the acute effects of schoolbag load on static and dynamic kinetics and kinematics in 10–13-year-old children mark kramer1, bridget grobler1 north-west university1 mark.kramer@nwu.ac.za background: excessive schoolbag loading may lead to unfavourable postural deviations and musculoskeletal pain. curvatures of the spine can be influenced by asymmetrical loading of the schoolbag, or by muscle imbalances between the dominant and non-dominant sides of the body, leading to (i) compensatory shifts in static and dynamic body postures, (ii) adjusted postural sway, and (iii) deviations in gait. methodology: sixty participants volunteered for the study and were subcategorised by age: 10 year-olds (n = 15), 11 year-olds (n = 15), 12 year-olds (n = 16), and 13 year-olds (n = 14). participants were evaluated for changes in (i) craniovertebral and sagittal shoulder postures, (ii) postural sway, and (iii) gait kinetics and kinematics during loaded and unloaded conditions. results: approximately 58% of participants exceeded a schoolbag mass of 15% bm, and 27% exceeded a schoolbag mass of 20% bm. significant differences were evident for those reporting pain and exceeding the 15% bm threshold compared to those with pain but below the 15% bm threshold (2 (1) = 5.79, p = 0.016, relative risk [rr] = 2.63, 95% ci [1.04, 6.62]). deviations were evident between loaded and unloaded conditions for: (i) craniovertebral angles (mdiff = -1.70 deg, 95% ci [-3.25, -0.15]) and sagittal shoulder angles (mdiff = 3.08 deg, 95% ci [-0.03, 6.19]), (ii) postural sway (mdiff = 70.29 mm2, 95% ci [63.55, 204.14]), and (iii) all plantar force (mdiff = 14-40 n) and pressure (mdiff = 44-199 n/cm2) values , as well as gait velocity (mdiff = -0.17 km.hr-1, 95% ci [-0.29, -0.04]); although none of these reached practical significance (cohen’s d: -0.28-0.26). conclusion: schoolbag loads significantly influenced plantar pressures and forces as well as sagittal shoulder postures, but not postural sway or gait velocity. most of the individuals evaluated exceeded the 15% bm threshold, and those exceeding the 15% bm threshold experienced 2.63 times the risk of experiencing pain compared to those below the threshold. therefore, schoolbag loads should be kept below 15% of bm. mailto:mark.kramer@nwu.ac.za o24: clustered cardiovascular disease risk among 8 to 13-year-old children from lower socioeconomic schools in gqeberha, south africa dolley d1, walter c1, du randt r1, pühse u2, bosma j12, degen j2, joubert n3, arnaiz p2, müller i2, gerber m2 nelson mandela university1, university of basel2, swiss tropical and public health institute3 danielle.dolley@mandela.ac.za background: it is estimated that 51% of south african deaths can be accounted for by noncommunicable diseases (ncds) yet just over half of south african children comply with the recommendation of 60 minutes of moderate to vigorous physical activity (mvpa) per day. the aim of the study was to determine the prevalence of individual and clustered cardiovascular disease (cvd) risk factors among children from lower socio-economic communities and to investigate the independent association between clustered cvd risk, mvpa, and cardiorespiratory fitness (crf). methodology: baseline data derived from the kazibantu study were collected in a cross-sectional analysis of 975 children, aged 8-13-years-old from eight quintile 3 schools. measurements included height, weight, waist circumference, blood pressure, fasting glucose, full lipid panel, 20 m shuttle run performance and accelerometery. the prevalence of individual cvd risk factors was determined using standardised cut-offs, and a clustered risk score (crs) was constructed using principal component analysis. participants with an elevated crs of 1sd above the average crs were considered “at-risk”. results: we found 424 children (43.3%) having at least one elevated cvd risk factor: 27.7% elevated triglycerides, 20.7% depressed hdl-c and 15.9% elevated total cholesterol. an elevated clustered risk was identified in 17% (n=104) of the sample; girls exhibited a significantly higher crs>1sd than boys (p=0.036). the estimated odds of an elevated clustered risk are doubled every 2 ml/kg/min decrease in vo2max (95% ci: 1.60-2.40 ml/kg/min) or every 50 min reduction in mvpa (95% ci: 1.27-4.33 min). conclusion: a relatively high prevalence of elevated individual and clustered cvd risk was identified. our results have also confirmed the independent inverse association of the clustered cvd risk with pa and crf, respectively, and indicate that increased levels of crf or mvpa may aid in the prevention and reduction of elevated clustered cvd risk. these findings emphasise the importance of an active lifestyle to counteract early-life cvd risk in under-served communities and schools such as those in the gqeberha, eastern cape region of south africa. mailto:danielle.dolley@mandela.ac.za o25: does physical activity, in part, explain the lower-than-expected mortality from covid-19 in sub-saharan africa? estelle victoria lambert1 research centre for health through physical activity, lifestyle and sport (hpals), dept of human biology, faculty of health sciences, university of cape town1 vicki.lambert@uct.ac.za background: the recent pandemic has highlighted the link between chronic, non-communicable diseases (ncds) and associated risk factors, that predict poor prognoses and severity of outcomes in relation to covid-19. globally, the infectious disease burden is typically inequitably distributed, with lmics experiencing the greatest share. however, in a recent publication by the new york times, journalists posited that sub-saharan africa had experienced a lower-than-expected number of “excess deaths” due to covid-19. the potential explanations offered included: younger age distribution, low testing rates, rural and undocumented deaths, and a more physically active population, spending more time outdoors. the latter explanation was discussed in a recently published commentary in progress in cardiovascular diseases (wachira et al., in press, https://doi.org/10.1016/j.pcad.2022.04.012). the aim of this preliminary investigation was to explore publicly-available data, in order to provide further insights into this phenomenon. methodology: publicly available data for 136 countries (17=lic, 35=lmic, 39=umic, 45=hic) were gathered from the who global health observatory, the world bank and worldometer (aggregated data in real-time concerning population, government, economics, environment, energy and health). variables included: total population, tests per million, cases per million, deaths per million, gini coefficient, world bank classification, percentage urbanised, and physical inactivity prevalence. linear regression analyses were conducted to predict covid-19 outcomes. results: descriptive data for countries by world bank classification showed that urbanisation ranged from 37.2% in lics to 75.6% in hics (p<0.001). similarly, physical inactivity prevalence was lowest in lics at 18% and highest in hics at 33.6% (p<0.001). covid-19 cases/deaths per million ranged from 3119 and 53, respectively in lics to 255516 and 1816, respectively, in hics (p<0.001). linear regression models including % inactivity (p=0.008), % urban (p=0.012) and hic vs others (p=0.025) explained 27% of the variance in deaths per million. a similar model, substituting sub-saharan africa for hics, explained a similar % of the variance in deaths per million (r2=0.274) and was protective. physical inactivity was not implicated in cases per million. conclusion: preliminary analyses suggest that per capita covid-19 mortality is linked to physical inactivity, urbanisation and is greatest in high-income countries. covid-19 cases were not linked to physical inactivity in this sample. these results provide indirect support for the role of physical activity in mitigating covid-19 severity, although more research is needed. mailto:vicki.lambert@uct.ac.za https://doi.org/10.1016/j.pcad.2022.04.012 o26: bring in the biokineticists: facilitating behaviour change in a low-resourced community sweetness j makamu-beteck1, francois g watson2, melainie cameron1, 3, sarah j moss1 phasrec, north-west university, potchefstroom1, numiq, north-west university, potchefstroom2, school of health and medical sciences, university of southern queensland, autralia3 sweetness.beteck@gmail.com background: to interpret and discuss the contributions of supervised exercise compared to standard clinic care on the perceptions and knowledge of risk factors for non-communicable diseases (ncds) and physical activity (pa) among women living in a low-resource setting in south africa. methodology: from 200 recruited participants, 172 women were assigned to either 24 weeks of supervised exercise training (intervention group), n=95 or 24 weeks of standard clinic care (control group), n=77. we used a convergent parallel mixed method to collect qualitative data and quantitative data at baseline, 12-weeks, and 24 weeks of the intervention. qualitative explorations consisted of focus group discussions assessing perceptions of ncds and pa. quantitative measurements included knowledge surveys of heart disease, biological (blood pressure, peripheral blood glucose and total cholesterol), body composition (weight, height, waist, and hip circumference) measures, and objective pa measurements over seven consecutive days of free-living with combined heart rate van accelerometry (actiheart®). qualitative content analysis was done using atlas.ti. quantitative data were analysed using linear mixed models. the health belief model was applied as the lens through which the mixed methods data were described and interpreted. results: the participants’ perceptions and understanding of ncd risk factors improved more among the supervised exercise group than in the control group. both groups reported significant increases from baseline to 24 weeks in pa knowledge (p ≤ 0.001) and heart disease knowledge (p ≤ 0.001). significant improvements in dbp (p ≤ 0.001), sbp (p≤0.001) and waist circumference (p=0.03) were reported for both groups. the exercise group showed a significant faster rate of reduction as compared with the control group in sbp (β = 4.10, t = 1.97, p = 0.05) and dbp (β = 3.81, t = 2.97, p ≤ 0.001). the control group had faster rate of reduction in waist circumference (β = -2.46, t = -2.68, p = 0.01). conclusion: the supervised exercise intervention improved perceptions of risk factors for ncd and pa after 24-weeks when participating in a supervised exercise intervention compared to women receiving standard clinic care. trial registration: pactr201609001771813 mailto:sweetness.beteck@gmail.com o27: energy expenditure, intensity, and perceived effort in recreational functional training lucilia mangona1, ledda almeida brasil2, antonio m. prista3, paulo t. farinatti2 higher school of sports science, maputo, mozambique1, graduate program in exercise and sport sciences, university of rio de janeiro state, rio de janeiro, brazil.2, research group for physical activity and health, faculty of physical education and sports, pedagogical university of mozambique, maputo, mozambique3 lucilia.mangona@gmail.com background: few studies have estimated the energy expenditure (ee) of functional training (ft) sessions, none of which are in actual conditions in training centres or involving recreational practitioners. this information would be useful to better understand the potential of tf as a strategy to achieve adequate physical activity volumes to promote health. the objective of this doctoral thesis was to quantify the ee during ft sessions using triaxial accelerometry, in adults without previous experience with the modality, in a commercial gym in the city of maputo (mozambique). the relative and absolute intensity and rate of perceived effort (rpe) were also assessed. additionally, data from ft were compared with those derived from continuous walking sessions (wlk). methodology: twenty-five volunteers with no previous experience with ft (11 men, 16 overweight, 38.8 ±9.3 years; 73.9±13.8 kg; 168.5 ± 8.5 cm) performed three training sessions interspersed with 48h (two familiarization and one assessment). ft circuit included four rounds of 12 exercises performed at all-out repetitions during 20 s, with 10-s intervals between rounds. wlk was performed for 25 min with intensity corresponding to scores 3-5 at borg cr-10 scale. results: outcomes were ee (kcal) and movement counts estimated by a triaxial accelerometer worn at the waist; heart rate reserve (%hrr); and rpe. ft sessions lasted on average 24 min and ee ranged between 124-292 kcal (188±41 kcal), corresponding to 5-8 mets (6.1±0.6 mets), and 70-80 %hrr (74±8%). the rate of movements (counts/min) showed that vigorous predominated over moderate intensity during ft and wlk (p=0.01), with similar ee. however, the relative intensity (74% vs. 55 %hrr, respectively; p=0.0001) and rpe (borg 5-8 vs. 3-5, respectively; p=0.0001) were higher in ft vs. wlk. conclusion: in conclusion, a short recreational ft circuit applied at a conventional fitness centre elicited ee and intensity compatible with recommendations to reduce cardiometabolic risk and improve cardiorespiratory fitness in participants with normal or overweight. this training modality should be considered as an alternative for health-oriented exercise programs for the general population. mailto:lucilia.mangona@gmail.com o28: environmental factors increase the risk of heat/ electrolyte disorders in ultramarathon races marlise dyer1, esme jordaan2, henno havenga3, nicola sewry1, martin schwellnus4 sport, exercise medicine and lifestyle institute (semli), university of pretoria1, biostatistics unit, south african medical research council (samrc), department of statistics and population studies, university of the western cape2, department of environmental sciences and management, north-west university3, sport, exercise medicine and lifestyle institute (semli), university of pretoria, ioc research centre, pretoria, south africa4 marlise.emmiej@gmail.com background: the comrades ultra marathon over 90km takes place every year between the towns of pietermaritzburg and durban . the event alternates between up runs (durban to pietermaritzburg) and down runs (pietermaritzburg to durban), over an undulating course. participants typically start the race between 5h29 and 6h04, depending on the individual seeding positions. participants are differentially exposed to various weather conditions along the route, most notably heat stress exposure which has been shown to contribute to medical-related illnesses during the race. the aim was to explore the ability of two indices, the wet-bulb globe temperature (wbgt) and the universal thermal comfort index (utci), to predict the risk of athletes developing heat/fluid conditions (heat illness, rhabdomyolysis, fluid and electrolyte disorders which included hypothermia, hyperthermia/exertion heat stroke, dehydration, (mild, moderate or severe), hyponatremia, other electrolyte disorders). methodology: two indices, namely the wet-bulb globe temperature (wbgt) and the universal thermal comfort index (utci), are explored to derive the environmental conditions on race day. daily weather conditions for the period 2014-2019 were gathered from south-african weather service (saws) weather stations in proximity of the race route along with era5 reanalysis data that represents a modelled environment of past weather conditions for the region. the wbgt and utci values were derived from these data sources for every hour from 05h00 until 18h00 and a cumulative heat exposure value was derived for each athlete. heat/electrolyte data from the down races for the years 2014, 2016, and 2018 were analysed. results: the correlation between the wbgt and utci values was 0.82. in total 443 athletes were treated for heat/electrolyte disorders. the prevalence of electrolyte disorders was 1.1% (1.0 to 1.2%). the modelling of heat/fluid conditions with utci showed a significant increase in risk with an increase in utci (pr=1.23 for every 2 units increase in utci; 95%ci: 1.16-1.3), p=0.0001) and with wbgt showed a significant increase in risk with an increase in wbgt (pr=1.7 for every 2 units increase in wbgt; 95%ci: 1.4-1.9), p=0.0001) conclusion: in both wbgt and utci, an increase indicates an increased risk of heat/electrolyte disorders in ultra-marathon races. mailto:marlise.emmiej@gmail.com o29: the risk markers associated with acute respiratory tract illness in rugby players during the super rugby tournaments (2013-2017), involving 102 738 player-days audrey jansen van rensburg1, dina c. (christa) janse van rensburg1, martin p. schwellnus2, charl janse van rensburg3, esmé jordaan3 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa1, sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa2, biostatistics unit, south african medical research council, south africa3 audrey.jansenvanrensburg@up.ac.za background: acute respiratory tract illness (artill) presents a significant health burden to elite rugby players and can disrupt training and competition performance. data of possible risk markers for artill in rugby players are limited. the aim was to determine the associated risk markers of artill in rugby players during the super rugby tournaments. methodology: team physicians completed daily illness logs in 537 professional male rugby players from all south african teams participating in the 2013-2017 super rugby tournaments (exposure: 1141 player-seasons, 102,738 player-days). information recorded includes player factors [age (years), height (cm); weight (kg); player position (forwards, backs), illness previous year], team factors [different teams], season factors [competitive season (year), phase of season (early, mid, late), number of matches (8, >8)], travel factors [home/away, last 7 days], location, match days and maximum wet bulb globe temperature (wbgt). main outcome measures included numbers, proportions, incidence (i: per 1000 player-days; 95% ci) and incidence ratio (ir: per 1000 player-days: 95%ci). results: throughout the 5-years, 305 artill were reported with an overall incidence of 2.9 (2.6-3.3). in the univariable regression analysis, the incidence of artill relative to competitive season 2013 was higher in 2015 (ir: 1.4; 1.0-1.9); and lower in 2016 (ir: 0.6; 0.4-0.9) and 2017 (ir: 0.5; 0.3-0.8). travel away from home (ir: 2.2; 1.7-2.8) and travel in the last 7 days (ir: 1.9; 1.5-2.4) are associated risk markers of artill compared to home-based periods (p<0.0001, respectively). in the multiple regression analysis, competitive season years and travel away from home are risk markers associated with artill (p<0.0001). maximum wbgt in the last 7 days (adjusted for season and travel) is not a risk marker associated with artill. age, bmi, player position, illness previous year, team involved, phase of season year and number of matches played are not significant risk markers associated with artill in super rugby players. conclusion: different competitive season years and travel home/away are risk markers associated with artill in rugby players during the super rugby tournaments. these findings are important in designing and implementing of artill prevention strategies in rugby players. mailto:audrey.jansenvanrensburg@up.ac.za o30: exercise associated muscle cramping is more severe for 56km runners compared to 21.1km runners esme jordaan1, martin schwellnus2, 3, 4, nicola sewry5 biostatistics unit, south african medical research council1, sport, exercise medicine and lifestyle institute (semli) and department of physiology, faculty of health sciences, university of pretoria, south africa2, international olympic committee (ioc) research centre, south africa3, emeritus professor, faculty of health sciences, university of cape town4, sport, exercise medicine and lifestyle institute (semli) and department of physiology, faculty of health sciences, university of pretoria, south africa5 esmerjdn@gmail.com background: exercise associated muscle cramping (eamc) is defined as a ‘painful spasmodic involuntary contraction of skeletal muscle that occurs during or immediately after muscular exercise’. our previous work from the 2012-2015 two oceans races showed that cramping is more prevalent among 56km runners compared to 21.1km runners (56km 19% vs 21.1km 9%). the aim was to compare the severity of cramping for runners in the longer distance versus the shorter distance. methodology: this was an observational study with a cross-sectional analysis. the data were from the 2012-2015 two oceans races (21.1km and 56km). the online pre-race medical history screening tool included a specific question related to the severity of eamc during or immediately after running in training or competition: “if you cramp, how severe is the cramping?”. the options for the responses were “mild (15min, stop exercising)”. the 76 609 race entrants were grouped as follows into 3 race distances: (1) only 21.1km, (2) both 21.1km and 56km (21.1/56km), and (3) only 56km races over the 4 years. results: the 3 race distance groups had 44 438 (58%) for 21.1km, 5 231 (6.8%) for 21.1/56km and 26 940 (35.2%) for 56km runners respectively in each group. overall, the responses to the severity of cramping were 0.7% severe, 4.2% moderate, and 8.9% mild. the %s of severe cramping in the 3 groups were 21.1km 0.5%, 21.1/56km 0.8% and 56km 1.2%. the relative difference between the groups was as follows; the odds of 56km runners cramping being more severe is almost 3 times the odds of 21km being more severe. the odds of 21.1/56km runners cramping being more severe is 2 times the odds of a 21.1km runner cramping being more severe. the odds ratios were different for age categories but not for genders. conclusion: there is a substantial difference in the severity of cramping for runners between the shorter and the longer races. this might not be true to the same extent for all age categories, and this will be investigated further. mailto:esmerjdn@gmail.com o31: specific chronic allergies as predictors of annual multiple injuries in individual distance runners sonja swanevelder1, nicola sewry2, martin schwellnus2, esme jordaan3 south african medical research council1, semli university of pretoria2, south african medical research council3 sonja.swanevelder@gmail.com background: a recent publication by the authors reported that runners who have been running recreationally for >20 years and those with multiple chronic diseases or a history of allergies were at a higher risk of multiple running-related injuries (mir). the aim was to determine if specific allergies were risk factors predictive of individual runners with a high annual mir. methodology: a retrospective, cross-sectional study at 4 annual (2012-2015) two oceans 21.1 km and 56km races in south africa with 75 401 consenting race entrants. running-related injury data were collected retrospectively through an online pre-race medical screening questionnaire. the average number of injuries for each runner by year was calculated by taking a runner’s race entry history and injury history into account and categorizing entrants into 4 mir categories (high, intermediate, low, and very low (reference)). follow-up multiple logistic regression modelling (odds ratios) was used to determine the role of specific allergies (any allergy, plant material allergy, animal material allergy, allergy to any type of medication) as risk factors predictive of a high mir (average >1 injury/year). results: of all entrants, 9.2% reported at least 1 injury, and 0.4% of entrants were in the high mir category; the incidence rate was 2.5 injuries per 10 runner-years (95% confidence interval (95%ci): 2.42.7). overall, having any chronic allergy was a significant predictor of runners in the high mir category: or=4.5 (95%ci: 3.3-6.0; p<0.0001). significant specific chronic allergy types predictive of runners in the high mir category were: plant material: or=3.5 (95%ci: 2.3-5.3; p<0.0001); animal material: or=3.1 (95%ci: 2.0-4.9; p<0.0001); and a medication allergy or=2.8 (95%ci: 1.8-4.3; p<0.0001), adjusting for sex, age group, race distance and taking allergy medication. conclusion: runners with a chronic allergy were at a higher risk of annually reporting multiple runningrelated injuries, more specifically plant material allergies, animal material allergies and an allergy to any type of medication. further investigation should include the possible role that specifically allergy medication plays with respect to a high mir. mailto:sonja.swanevelder@gmail.com o32: epidemiology of injuries in wheelchair rugby at the london 2012 and rio 2016 paralympic games maaike eken1, phoebe runciman1, wayne hough1, wayne derman1, 2 institute of sport and exercise medicine (isem), department of sport science, faculty of medicine and health sciences, stellenbosch university, cape town, south africa1, international olympic committee research centre, south africa2 meken@sun.ac.za background: based on the nature of the sport, the risk of injuries is high in wheelchair rugby, given the sport’s high impact collisions, falls, and high risk of concussion. previous research has alluded to high injury rates for wheelchair rugby compared to other sports at the paralympic games. therefore, it is important to examine the incidence and nature of injuries in this sport, which may facilitate the development of strategies to prevent injuries. the aim of this study was to investigate the injury incidence rate and nature of injuries in wheelchair rugby during the london 2012 and rio 2016 paralympic games. methodology: injuries were recorded by all medical team staff members during the london 2012 and rio 2016 paralympic games, using the web-based injury and illness surveillance system (web-iiss) tool. the incidence rate (ir) of injuries was calculated per 1000 athlete days. results: in total, 175 athletes participated in wheelchair rugby in london 2012 and rio 2016 combined. in 29 (16.6%) of these athletes, one or more injuries were reported. a total of 38 injuries were documented, resulting in an ir of 15.5 (95%ci 25.9 – 50.1) injuries. most athletes who reported injuries had a spinal cord injury or spina bifida (82%). half of the injuries were acute injuries (48%), of which mostly upper limb injuries (76%). at rio 2016, only one out of twenty reported injuries led to a time loss of two days. conclusion: the results of this study showed that most of the injuries reported among wheelchair rugby athletes during the london 2012 and rio 2016 paralympic games were acute upper limb injuries. of the injuries sustained during the rio 2016 paralympic games, less than 5% resulted in time lost from training and competition, most of which were hand and wrist laceration, abrasion, soft tissue bruising or haematoma. hence, it can be suggested that wheelchair rugby resulted in a high incidence of non-time loss injuries. future research is necessary to investigate whether prevention strategies for upper limb injuries or rule changes can lead to a reduction of injuries among wheelchair rugby athletes. mailto:meken@sun.ac.za o33: an epidemiological study into the prevalence and types of injuries affecting adolescent tennis players in south africa kirsty elliott1, 2, paola silvia wood2, ernst pieter krüger2, 3 sport, exercise medicine and lifestyle institute (semli), sport science unit, faculty of health sciences, university of pretoria, south africa1, division of biokinetics and sports science, department of physiology, faculty of health sciences, university of pretoria, south africa2, institute for sports research, university of pretoria, south africa3 kirsty.elliott@semli.co.za background: injuries in tennis are reported as a major concern in youth tennis players worldwide, this trend has not been studied in south africa. the aim of this study of adolescent tennis players was to determine the injury prevalence, site and types of injuries that occur and identify possible risk factors for injury in junior tennis players in south africa. methodology: a prospective epidemiological study design was used to conduct the applied research. male and female (67%) players (n=30) aged between 13-19yrs with an average of 7.1± 1.86yrs playing experience participated. questionnaires were used to collect: playing and injury history, daily training diaries and self-reported injury occurrence (osics-10 classification system) over 26 weeks. overall injury rate / 1000 hrs of play, injured body segment, tissue type and mechanism were captured during the major competition period on the south african tennis calendar. results: an injury rate of 0.357/1000 hours of play was reported with 27 new conditions and 40 recurring conditions being reported over the 26 weeks. lower limb and trunk injuries were the most common (29.6% each), followed by upper limb injuries (22.2%) and there were no injuries to the head and neck. muscle and tendon sprains were the most common (46%), followed by joint and ligament injuries (23%). the mechanism of the injuries reported was split between acute (55%) and chronic overuse (45%) injuries but chronic injuries accounted for (61%) of the rest days taken due to injury. the only risk factor identified to be associated with total number of injuries was the number of resting days (p=0.28). conclusion: overall injury rate recorded falls on the lower side when compared to rates found in previous studies. the trend of lower body injuries being more common than upper body occurrence was consistent with previous research. the epidemiology of injuries provides insight for the development and implementation of injury prevention programmes. descriptive training results such as the mean training time (hrs/week), strength and conditioning training (hrs/week) and training to competition ratios should be further investigated to fully understand the major risk factors for injury occurrence. mailto:kirsty.elliott@semli.co.za o34: impact of sars-cov2 containment measures in physical activity and nutrition habits in african urban centers: a study in mozambique antónio prista1, 2, 3 physical activity and health research group1, fefd2, universidade pedagógica de maputo3 aprista1@gmail.com background: in response to the sars-cov2 pandemic, a large set of measures was adopted by the authorities. these measures are expected to have a significant impact on several socio-economic and cultural habits, which include physical activity and nutrition. the assessment of this impact in opposition to its advantages in the control of the pandemic must be evaluated. thus, the aim of this study was (1) to assess the impact of sars-cov2 containment measures on physical activity and nutritional habits in an urban population of mozambique and (2) to evaluate the advantages of those measures for the pandemic control. methodology: a total of 7,415 men and women aged between 18 and 65 years were surveyed in 9 provincial capital cities of mozambique by specifically trained observers about the impact of the measures on physical activity and nutritional habits. in turn, an evaluation of the impact of the measures in the evolution of the pandemic was performed by using the different official measures opposing to the subsequent evolution of rates of positive cases, hospitalization and deaths. results: almost all participants reported leaving home on a daily basis but only 5.5% for physical exercise. almost half of the participants (48.6%) reported having been affected by their family income. physical activity, when compared to what was habitual before the pandemic, decreased for 72.2% of people, while 27% of respondents said they eat less fruit and 29% less vegetables. in turn, the trend for positive cases, hospitalization and death rates did not show any association with the official measures. conclusion: it was concluded that in the main urban centres in mozambique, physical activity and nutritional habits were affected by the measures, although those measures did not show an association with an effective pandemic control. mailto:aprista1@gmail.com o35: the incidence of illness and injury in master paralympic athletes: a descriptive cohort study of the >35 year age category in the 2012 to 2018 summer and winter paralympic games phoebe runciman1, melissa janse van vuuren1, pieter boer2, esme jordaan3, wayne derman4 institute of sport and exercise medicine, department of sport science, stellenbosch university1, cape peninsula university of technology, cape town, south africa2, biostatistics unit, medical research council, cape town, south africa3, international olympic committee research centre (south africa)4 para@sun.ac.za background: there are limited studies regarding the illness and injury patterns of older para athletes. the aim of this study was to describe illness and injury incidence in master paralympic athletes during the london 2012, sochi 2014 winter, rio 2016, and pyeongchang 2018 winter paralympic games. methodology: this study forms part of a larger epidemiological study and made use of illness and injury data regarding master paralympic athletes collected during the pre-competition and competition periods during the 2012-2018 paralympic games. results: a total of 457 and 83 illnesses were reported during the summer games (sg) and winter games (wg), respectively. some differences in illness incidence could be seen between sg and wg (london: ir 14.4; sochi: ir 22.6; rio: ir 11.8; pyeongchang: ir 15.4) and illnesses in the respiratory system (ir 3.2 – 6.6), dermatologic system (2.1 – 3.8) and gastrointestinal system (1.8 – 3.1) were most common. a total of 397 and 115 injuries were reported during the sg and wg respectively. injury ir during the wg (sochi: ir 31.5; pyeongchang: ir 21.1) was double compared to the sg (london: ir 12.1; rio: ir 10.6). upper limb (london: ir 5.9; sochi: ir 14.1; rio: ir 4.2; pyeongchang: ir 11.0) and sudden onset (london: ir 5.9; sochi: 18.8; rio: ir 4.5; pyeongchang: ir 16.7) injuries were two-fold higher during the wg compared with the sg. conclusion: except for sochi 2014 wg, the incidence of illness between sg and wg were similar. the wg had a higher incidence of injuries, indicating that master paralympic athletes are potentially more likely to report injuries. respiratory, dermatologic and gastrointestinal illnesses, as well as upper limb and sudden onset injuries, were prevalent in both the sg and wg. mailto:para@sun.ac.za o36: classification of junior ethiopian football players using anthropometric and physical fitness attributes: developing a predictive model leyekun gebru1, johan van heerden2, orthodox tefera3 department of biokinetics, exercise and leisure sciences (sports science) school of health science, university of kwazulu-natal, durban, republic of south africa1, school academic leader: research school of health sciences department of biokinetics, exercise and leisure sciences (sports science) school of health science, university of kwazulu-natal, durban, republic of south africa2, graduate school of business and leadership university of kwazulu-natal, durban, republic of south africa3 leyetad@gmail.com background: the recruitment and early selection of players into a specialised football development programme and centres of excellence have been considered as an essential factor for the long-term development of a footballing career (le gall, carling, williams, & reilly, 2010). the aim of the present study was to develop a predictive model that identifies the anthropometric and physical fitness that best predicts the status and playing positions (n=400; 15–17 years) in the ethiopian male youth soccer development programme. methodology: anthropometric measurement in terms of mass, height, relative body fat, and derived body composition was conducted using the international society for the advancement of kinanthropometry (isak) guidelines. fitness was measured by sprint tests (10 meters, 20 meters and 40 meters flat), the illinois agility test, vertical jump test and estimated vo2 max. factorial anova was used to test the relationships between players’ residence, position, and respective interaction terms. additionally, discriminant analysis was used to identify the variables that contributed to the selections. results: sports camp residence players were significantly different in all anthropometric attributes as well as physical fitness attributes at p<0.05 except vo2 max. the percentage of players who were correctly classified in the original groups was slightly lower than the percentage calculated after the analysis was performed for the total sample (86%) and after calculation by position (86 – 90%). conclusion: the study concluded that speed assessed in10m, 40m, vertical jump, and height were the discriminate attributes of players by the residential unit in ethiopian junior football players. it is recommended that anthropometrical and physical fitness attributes are important in the assessment and selection of young football players with the potentials for higher-level performance selection. mailto:leyetad@gmail.com o37: injury profiles differ by athlete impairment type during the 2012 and 2016 summer paralympic games: a combined analysis of 101 108 athlete-days faatima adam1, wayne derman2,3, martin schwellnus3,4, pieter boer5, esme jordaan6, phoebe runciman6 department of sport science, faculty of medicine and health sciences, stellenbosch university (cape town, south africa)1, institute of sport and exercise medicine (isem), department of sport science, faculty of medicine and health sciences, stellenbosch university, cape town, south africa2, international olympic committee (ioc) research centre (south africa)3, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria (pretoria, south africa)4, department of human movement science, cape peninsula university of technology (cape town, south africa)5, biostatistics unit, medical research council, cape town, south africa6, faatima.adam@gmail.com background: background: musculoskeletal injury rates in para athletes have been shown to differ by age, sex, sport, environment, chronicity, and anatomical area. the relationship between an athletes’ medical impairment and injury rates have not yet been comprehensively studied. objectives: to describe the effect of an athletes’ underlying medical impairment on their incidence of injury by age, sex, games period, sport, chronicity, and anatomical area. methodology: a combined analysis of injuries sustained by athletes during the london 2012 and rio 2016 summer paralympic games (s-pgs) was performed. a total of 7222 athletes were monitored over the two games periods, comprising 101 108 athlete-days. injury data were reported by impairment type: brain disorders (bd), limb deficiency (ld), neuromuscular disorders (nmd), spinal cord injuries (sci), visual impairment (vi), and ‘all others’ (oth: impaired passive range of movement (iprom), intellectual impairment (ii), leg length difference (lld), short stature (ss), and unknown) impairments. results: a total of 1143 injuries were reported in 980 injured athletes over both s-pgs. athletes with vi (ir 13.6) and nmd (13.3) had high injury incidence, followed by sci (11.1), ld (10.9) and bd (9.1). precompetition period incidence was higher (ir 13.8) than the competition. acute sudden onset injuries (ir 5.8) were more common than gradual onset injuries (ir 3.7), except for athletes with nmd (ir 5.9). athletes with nmd and sci were associated with higher rates of upper limb injuries and athletes with vi,bd and ld with lower limb injuries. the incidence (i) of injuries for the various sports disciplines differed significantly for vi athletes (adjusted for sex and age) (p<0.0001). conclusion: the findings from this study contribute toward advancing the understanding of impairmentrelated factors associated with injuries in athletes during summer paralympic sports. clinicians working with para athletes can gain impairment-specific information for training and injury prevention. clinicians should work around; (1) decreasing precompetition injuries in athletes with musculoskeletal impairments, (2) prioritise postural control and balance in athletes with vi, and (3) consider biomechanical compensations and assistive device usage as contributors to injury in athletes with nmd. mailto:faatima.adam@gmail.com o38: muscle activation during the modified clinical test for sensory integration and balance (mctsib) in active unilateral transtibial amputees sarah arnold1, lara grobler1, laura-ann furlong2, ranel venter1 stellenbosch university1, limerick university2 sarnold@sun.ac.za background: balance tasks pose a specific challenge to utta after amputation often resulting in a fear of falling. there is limited understanding of postural control and muscle activation during balance tasks. understanding the muscle activation during functional tasks could inform the evidence-based rehabilitation exercise selection. the aim of the study was to determine the muscle activation in unilateral transtibial amputees (utta) during the modified clinical test for sensory integration and balance. methodology: surface electromyography (noraxon, usa) was used to determine lower limb muscle activation in six unilateral transtibial amputees (34 ± 5 years, 5 men & 1 woman) during the mctsib. raw data were filtered using a high pass, low pass and bandpass eighth-order butterworth filters. fullwave rectification and smoothing (50ms window were applied. peak amplitudes were determined per muscle, per activity and recordings were then normalized to the peak amplitudes. ethical clearance and participant consent were attained prior to testing. effect sizes (cohen’s d) were used to determine meaningful practical differences. results: significant differences were found in muscle activations between surface conditions as well as between the affected and unaffected sides of the utta. affected side vastus lateralis obliques (vlo) muscle activation was greater (d=0.5, medium) during the eyes open on a firm surface than on a foam surface. vlo had greater activation on the affected side than the unaffected side while eyes were closed on a firm surface (d=0.8, large). affected side bicep femoris (bf) muscle activation was greater (d=0.7, medium) during the eyes open on a firm surface than on a foam surface. during the eyes open on a firm surface, the bf muscle activation was greater (d=0.7, medium) compared to the eyes closed on a foam surface. tibialis anterior muscle activation was greater (d=0.8, large) during the eyes open on a firm surface compared to eyes closed. conclusion: the importance of proprioceptive and balance training is emphasized. evidence-based exercise selection informed by muscle activation under specific conditions has been shown to be valuable. this can contribute to reducing the fear of falls, improving prosthetic trust and improving sensory integration in utta. quality of life can be maintained as the utta ages. mailto:sarnold@sun.ac.za o39: the comparison of lower limb kinematics across stroke rates among male rowers during ergometer rowing and the influence of lower limb strength lisa heyneke1, andrew green1, warrick mckinon2 university of johannesburg2, university of witwatersrand2 heynekelisa@gmail.com background: rowing is a complex sport that requires an efficient technique for optimal performance and injury avoidance. the rowing stroke is a cyclic movement pattern in a closed chain. a biomechanical evaluation of rowing kinematics enables the quality of the rowing technique to be analysed. kinematic analysis of the lower limb is important as these muscles are the primary generators of force and power in rowing. the purpose of this study was to compare lower limb kinematics during rowing at different stroke rates (20, 26, and 30 strokes/minute) among university-level male rowers. methodology: three-dimensional kinematics of 16 university-level rowers (mean age: 21.5 years, height:184.1cm, mass: 78.6kg) were recorded at a rate of 100hz on the stationary ergometer at three different stroke rates: 20, 26, and 30 strokes/minute. bilateral hip, knee, and ankle angles were compared using spatial parametric mapping (smp) across the three-stroke rates (anova). results: the anova spm test revealed significant differences in all joint angles across the stroke rates. both hip angles demonstrated significant differences across the stroke rates at various periods of the stroke cycle. both knee angles were significantly different (p<0.001) across the stroke rates for the last 90% of the stroke cycle. both ankle angles were significantly different (p<0.001) across the stroke rates for the last 80% of the stroke cycle. the post-doc analyses revealed that the largest difference in all joint angles was between stroke rates 20 and 26. for the knee and ankle angles, the least significant differences in the stroke cycle were seen between stroke rates 26 and 30. conclusion: this study found that joint angles and lower limb kinematics are significantly different across the stroke rates in ergometer rowing. it is important to understand how kinematics change during the rowing stroke as the rowing technique plays a major role in success. kinematic changes in rowing can additionally be linked to strength components such as torque and power which may further facilitate performance enhancement and injury prevention. mailto:heynekelisa@gmail.com o40: the effect of countermovement jump initiation detection methods on discrete performance variables cassidy de frança1, matthew jordan2, helen bayne1 department of physiology, faculty of health sciences, university of pretoria, south africa1, faculty of kinesiology, university of calgary, canada2 cassidyjaye@gmail.com background: the calculation of countermovement jump (cmj) performance metrics is based on the impulse-momentum theorem that allows vertical centre of mass velocity to be determined from vertical ground reaction force (vgrf). an important methodological consideration is the detection method for true initiation of the cmj from a stationary start. the aim of the study was to investigate if different initiation detection methods have an effect on cmj performance variables. methodology: ethical approval was obtained to analyse the force-time data of 21 athletes who performed the cmj as part of routine testing. force-time data were analysed using the shiny vertical jump analysis app (https://github.com/mattsams89/shiny-vertical-jump). two initiation methods were applied. bodyweight (bw): vgrf over 1-second of quiet standing. method 1: the point where vgrf decreased to bw-5sd; method 2: used an algorithm to search backwards from bw-5sd to determine if the inverse (bw + 5sd) occurred within the previous 100 ms. the last point before this inverse threshold was initiation. metrics commonly used to analyse jump performance were compared between methods using paired sample t-tests. results: statistically significant differences (p < 0.05) occurred for time to take-off (0.86 ± 0.08 s; 0.80 ± 0.07 s), unweighting phase duration (392 ± 57 ms; 337 ± 41 ms), propulsion phase duration (290 ± 25 ms; 289 ± 25 ms), net impulse (2.63 ± 0.25 ns.kg-1; 2.60 ± 2.61 ns.kg-1), peak power (49.5 ± 6.57 w.kg1; 49.1 ± 6.63 w.kg-1) , modified reactive strength index (0.41 ± 0.08; 0.44 ± 0.09), average rate of force development (1808 ± 421 n.s-1; 2037 ± 560 n.s-1) and jump height (calculated from impulse) (0.36 ± 0.07 m; 0.34 ± 0.07 m). no statistically significant differences were observed for all other metrics analysed (jump height from flight time, braking phase duration, peak force, and force at zero velocity). conclusion: initiation detection methods significantly affect cmj performance variables including jump height, phase durations, and timing-related metrics, but not the peak force value and therefore are not interchangeable when determining true initiation of the cmj. accounting for initiation with an increased force prior to decrease is recommended to calculate accurate cmj performance and phase variables. mailto:cassidyjaye@gmail.com https://github.com/mattsams89/shiny-vertical-jump o41: eccentric movement strategy predicts stretch-shorten cycle preload during countermovement jumps darius sangari1, helen bayne1, john cronin2 department of physiology and sport, exercise medicine and lifestyle institute, faculty of health sciences, university of pretoria1, faculty of health and environmental sciences, sports performance research institute new zealand, auckland university of technology.2 dsangari1@gmail.com background: the coupling of eccentric and concentric muscle action is common in sporting movements and is referred to as the stretch-shorten cycle (ssc). the ssc elicits a performance-enhancing effect as the height achieved in the countermovement jump (cmj) has been observed to be higher than from concentric-only squat jumps. net force at the end of the cmj eccentric phase (force at zero velocity – f0v) is positive, whereas squat jumps performed from a static start where the vertical ground reaction force equals bodyweight. this may provide a quantitative indication of ssc preload. it is theorised that eccentric movement strategies (such as the amplitude and rate at which the eccentric contraction is performed) will influence the preload achieved. methodology: a total of 202 competitive athletes (females: n = 83 and males: n = 119) from various sports volunteered to participate in this study. each participant performed three cmj’s (without armswing) on a dual force platform (jm6090-06, bertec, usa) and data was collected using forcedecks software (vald performance, australia). a pearson’s correlation was used to determine the strength of the relationship between eccentric strategy variables and relative f0v (f0v/bw). a hierarchical regression model was used to determine the predictive potential of the eccentric strategy variables. statistical significance was set at p < 0.05. the variables selected to represent cmj strategy were; net minimum eccentric force (fmin), eccentric peak velocity (vecc), relative braking impulse (iecc/bw) and countermovement depth (cmdepth). results: large significant correlations (r > 0.50; p < 0.05) were observed between f0v/bw and fmin, vecc, and iecc/bw for both male and female athletes. the hierarchical linear regression revealed that 67.1% and 63.7% of relative f0v values can be predicted using vecc, cmdepth and fmin for females and males, respectively. conclusion: a cmj strategy that utilizes a greater unweighting acceleration (lower fmin and greater vecc) and greater braking phase deceleration (greater iecc/bw) will increase the magnitude of preload achieved (greater f0v/bw). it is suggested that practitioners aiming to improve ssc preload should consider verbal instructions and training methods that may influence eccentric movement strategies. mailto:dsangari1@gmail.com o42: change of direction time vs change of direction deficit: is there a need to assess both? christo van zyl1, helen bayne1, jason tee2 department of physiology and sport, exercise medicine and lifestyle institute, faculty health sciences, university of pretoria1, carnegie applied rugby research (carr) centre, carnegie school of sport, leeds beckett university, leeds, united kingdom2 christo.vanzyl@semli.co.za background: change of direction (cod) ability has been related to decisive moments in a team sport that could impact the outcome of a match. change of direction is a component of agility that is described as the ability to decelerate, change movement direction, and accelerate again where no immediate reaction to a stimulus is required, thus the direction change is pre-planned. change of direction deficit (codd) is a calculation used to isolate the ability to change direction from the ability to sprint in a straight line. this has been suggested to provide a more isolated measure of cod ability which is not influenced by linear speed qualities. thus, we aimed to determine the rank order relationship between cod time and codd. methodology: forty-five athletes that consisted of male high school rugby players (n = 20), male university-level hockey players (n = 12), and female university-level hockey players (n = 13) participated in this study. field-based testing consisted of a 20-m linear sprint (0-, 5-, 10-, and 20-m splits) and 180° (505 cod test), 90°, and 45° cutting tasks. the time between the 10-m and 20-m splits in the linear sprint test was subtracted from the time to complete the cutting task to determine the codd. spearman’s rank order correlation was performed between cod and codd for the various cutting tasks. results: spearman’s rank order correlations showed nearly perfect (r = 0.94, p < 0.001), very large (r = 0.897, p < 0.001), and very large (r = 0.879, p < 0.001) relationships between cod time and codd during the 180°, 90°, and 45° cutting tasks respectively. conclusion: codd has been suggested to isolate cod ability from sprinting ability. our results indicate that there is a strong correlation between cod and codd and thus the addition of codd may not be necessary. in particular as athletes with a fast cod time will most likely have a fast codd. however, practitioners working with athletes that have a slow cod time could find value in calculating codd to help identify if the problem is with straight line sprinting or their ability to change direction. mailto:christo.vanzyl@semli.co.za o43: cardiovascular autonomic nervous system-related discriminators of time trial power output in endurance-trained athletes ben coetzee1, ninette thiart1, christo bisschoff1 physical activity, sport and recreation research focus area, faculty of health sciences, north-west university north-west university1 ben.coetzee@nwu.ac.za background: the study aimed to determine whether the pre-test heart rate variability (hrv) and posttest heart rate recovery (hrr) parameters of endurance-trained athletes can serve as significant discriminators between higher and lower average relative time trial (tt) power outputs. methodology: ten competitive cyclists, and ten competitive middleand long-distance male athletes participated in the study. heart rate was measured before and after a 5-km treadmill running on a woodway pro xl treadmill or a 20-km cycling tt on a wattbike pro air trainer via a fix polar hr transmitter belt and monitor. kubios hrv premium software was used to analyse the series of r-rintervals and determine the pre-test hrv. the hrr was calculated in absolute and relative values at 60 seconds post-test. the average power output of athletes during the running tt was determined by the running power equation of van dijk and van megen (2017), whereas the power output of the cycling tt was obtained from the wattbike. the participants were allocated to a lower and higher power output group, respectively according to their tt relative power outputs. forward stepwise discriminant analyses determined the power of different pre-test hrvand post-test hrr-parameters to serve as discriminators of athletes and cyclists with low or high tt power outputs. results: pre-test power high frequency (hf) (%) and low frequency (lf):hf ratio were identified as the only hrv-related variables that significantly discriminated between the highand low-power groups. the hrv-based forward stepwise discriminant analysis model was 90% accurate in classifying the participants into their respective groups. none of the hrr-related variables served as strong or significant discriminators between the lowand high-power groups. conclusion: in conclusion, results suggest that power hf (%) and lf:hf ratio can be used as significant discriminators between athletes and cyclists who can be categorized into different groups according to their average relative tt power outputs. the ans of endurance athletes who can deliver more power during execution of the tt showed a bigger inhibition of the parasympathetic nervous system, and a simultaneous enhancement in sympathetic activity. mailto:ben.coetzee@nwu.ac.za o44: protein supplements in south africa: high protein-content products or a case of misinformation? mandisi sithole1, gary gabriels1 university of the witwatersrand1 0507258d@students.wits.ac.za background: in recent years, the popularity of protein-based supplements has increased due to increased consumer demand and claims of high-quality protein it conveys. however, studies have revealed that certain supplements may not contain the precise amounts of protein content stated on product labels. methods such as the dumas and kjeldahl, which are often used to assess protein concentrations in these products, are insufficient because other nitrogen-based molecules present in the sample may interfere and result in an incorrect protein content determination. the purpose of the study was to use a multi-protein assay approach to quantify protein concentrations in protein supplement products commercially accessible in south africa. methodology: twenty-one protein supplement products were tested in the laboratory using the bca, lowry, and bradford assays results: protein concentrations (p<0.05) were lower in bradford, bca, and lowry by 95%, 86 %, and 67%, respectively. protein content determined by the bradford assay was much lower than that determined by the other assays, owing to its limitation in identifying proteins smaller than 3000da. there was no significant variation in protein content between the claimed values on labels and the goods tested using the lowry assay in 33% of the cases. an interference investigation revealed that quantities of melamine, cyanuric acid, and uric acid of more than 100g.ml-1 had a minor effect on all three assays, but lower values had no effect. conclusion: based on the findings of this study, protein supplements sold in south africa have lower concentrations of protein than what is stated on the labels. this suggests that manufacturers could be estimating protein content inaccurately or simply falsifying it. mailto:0507258d@students.wits.ac.za o45: age, skeletal maturity and growth velocity as injury risk factors in elite youth football (soccer) players aged 11 to 15 years: a three-season prospective study eirik halvorsen wik1, karim chamari2, montassar tabben2, valter di salvo3, warren gregson3, roald bahr4 institute of sport and exercise medicine, faculty of medicine and health sciences, stellenbosch university, tygerberg, south africa1, aspetar sports injury and illness prevention programme, aspetar orthopaedic and sports medicine hospital, doha, qatar2, football performance and science department, aspire academy, doha, qatar3, oslo sports trauma research center, department of sports medicine, norwegian school of sport sciences, oslo, norway4 ewik@sun.ac.za background: growth and maturation are considered risk factors for injury in youth football, yet firm conclusions cannot be drawn from the existing research. our aim was to explore the main and combined effects of age, skeletal maturity and growth velocity on injury risk in elite academy players. methodology: anthropometric (triannual height and body mass assessments), maturity (fels skeletal age from annual hand/wrist x-rays), injury (time-loss injuries recorded by team physiotherapists) and exposure (individual training/match minutes recorded by team sport scientists) data were collected prospectively over three seasons in an elite academy, including 95 male players (11-15 years). we compared the relative model quality of mixed-effects logistic regression models, with growth velocity (cm/year or kg/year) for 223 growth intervals (start to mid-season or mid-season to end, average 113 days) included as fixed effects, and adjusted for age or maturity plus load (average hours/week). associations were interpreted as practically relevant based on the confidence interval for odds ratios, using thresholds of 0.90 and 1.11 to define small beneficial and harmful effects, respectively. results: during the growth intervals, 161 index injuries and 21712 exposure hours were recorded. change in body mass combined with maturity best explained overall and gradual onset injury risk, while change in height combined with maturity best explained the risk of sudden onset, bone tissue and physis injuries. no growth × age/maturity interaction effects were seen. older age was associated with small harmful effects on overall (or adjusted for stature change: 2.61, 95%ci: 1.15-5.91) and sudden onset (or adjusted for body mass change: 1.98, 1.17-3.37) injury risk. significant associations (p<0.05) were observed for body mass and maturity on sudden onset injuries, and for load on gradual onset, bone tissue and physis injuries; however, these were not considered practically relevant based on our predefined thresholds. conclusion: our findings could not support changes in height or body mass over an academy semester as injury risk factors. older age was, however, associated with an increased risk of overall and sudden onset injuries. future studies should strive to include larger samples, starting from pre-adolescence, to enable within-subject analyses and better understand the relationship between growth, maturation and injuries. mailto:ewik@sun.ac.za o46: development of a toolkit to assess health-related quality of life amongst patients with selected noncommunicable diseases lynn smith1, heather morris-eyton1 university of johannesburg1 lynnvr@uj.ac.za background: although south africa has made significant progress in reducing the risk associated with noncommunicable diseases (ncds), the country still faces health inequities and inequalities within the healthcare sector. lowand middle-income countries, such as south africa, are called to expand their healthcare capacities to respond effectively to the increased burden of ncds. an integrated approach to the broad spectrum of ncds may provide the most cost-effective method for treatment, with a focus on health-related quality of life (hrqol). this study aimed at developing a toolkit to assess the hrqol of patients with hypertension, type 2 diabetes and cardiovascular disease. methodology: a sequential and exploratory mixed method research design was utilised. focus group discussions and semi-structured interviews were conducted with an expert panel (n=12). this process elucidated the development of a questionnaire assessing hrqol. this questionnaire was piloted and amended according to the feedback received. it was administered to patients (n3=257) across two-time intervals, three weeks apart. principle component analysis was performed on all items and results were used to determine validity and reliability using the pearson and spearman correlation coefficients, the interclass correlation coefficient (icc) and the coefficient of repeatability (cr). results: the toolkit consists of a long (37 items) and short (25 items) form questionnaire. both questionnaires yielded an excellent pearson’s r (0.89*; 0.89*), spearman’s rho (0.88*; 0.89*), and icc (0.94; 0.94). the coefficient of repeatability for both the long and short form were considered acceptable, at ±12.04% and ±12.50%, respectively. conclusion: the toolkit questionnaires are highly reliable and provides healthcare practitioners with a starting point for treatment, aiding in the prescription of individualised, multifactorial treatment programmes. these are tailored specifically to improve hrqol and the progression towards healthier lifestyles. in addition, the results of this study encourages a palliative approach to healthcare, improving the patients’ hrqol through the prevention and relief of disease specific suffering. mailto:lynnvr@uj.ac.za o47: body composition with nuclear and isotope technology application within the african region m.a. monyeki1 physical activity, sport and recreation research focus area, faculty of health sciences, north-west university, potchefstroom, south africa1 andries.monyeki@nwu.ac.za background: human body composition measurements are methods suitable for nutritional assessment and are of interest to sports scientists, nutritionists and health professionals. the increasing prevalence of childhood obesity, inactivity and lifestyle diseases, compiles increasing need for body composition methods with greater sensitivity and precision. purpose: the purpose of the study was to determine the level of agreement between body size selfperception and actual body size determined by body mass index (bmi) and body fatness measured by the deuterium dilution method (ddm); and compares body fat (%bf) determined using bioelectrical impedance analysis (bia) and %bf predicted from skinfolds equations in south african children. methods: a cross-sectional study with 299 (125 boys; 174 girls) 6to 8-year children was performed. perceived body image was assessed silhouettes. total body water and fat free mass were determined with deuterium oxide dilution (ddm), and predicted using bodystat (1500) with 50khz frequency. bland altman plots determined the level of agreements. statistical package for social sciences (spss v27®) analysed the data. results: bmi z-scores, thinness grade 1 (12%), thinness grade 2 (3%), overweight (9%), obese (2%); body image, underweight (32%), overweight (9%), and obese (2%) perceived their body size as underweight, normal, overweight, and obese; and ddm, 2.5% underweight, overweight (22%), obese 30%. the application of silhouettes and bmi resulted in either overestimation or underestimation of own body size. level of agreement between body size perception, body fatness, and bmi was poor. significant paired mean differences were found for body mass index (bia) and slaughter (t201 =33.896, p<0.001), wickramasinghe (t201 = 4.217, p<0.001), and dezenberg (t201 =19.910, p<0.001). the blant-altman plots show relatively large positive and negative deviations from the mean difference lines, and trends of systematic under-and over-estimation of %bf across the %bf spectrum. conclusion: perceived body image and bmi (which remains a practical tool for obesity surveillance, it should be consider in future studies) over or underestimated body fatness, whilst the criterion methods provided a good body fatness classification. scalable measures to allow for more accurate self-assessment are urgently needed–one approach is behavior change communication at all levels. as such, age-specific %bf equation incorporating optimum methods using ddm are needed. mailto:andries.monyeki@nwu.ac.za o48: physical fitness of school-age children and youth living in and island in mozambique gomes nhaca1, timoteo daca1, antonio prista1 physical activity and health research group, faculty of physical education and sports, pedagogical university of maputo, mozambique1 nhacagomes@gmail.com background: physical fitness (pf) is associated to health and performance being important from the early days of life. the pattern of pf in school age fitness in an island environment in mozambique are unknown. aim: to evaluate the levels of physical fitness of school-age children and young living in an island environment methodology: the study is part of the human biological variability project in mozambique and was carried out in “inhaca” island in 2019. sample was composed by 740 children and young aged 6-17 (boys=378; girls=362). the standardized protocols of the aahperd (mile run and sit and reach) and fitnessgram (horizontal impulsion, manual dynamometry, abdominal resistance strength and 10x5 meters sprint) batteries were applied. ancova was used to analyzed data as a function of sex having age as covariate. comparison with other mozambican studies in rural and urban areas were made using one-way anova results: age-adjusted performance indicated significant differences between boys and girls in hand dynamometry (p=0.001), horizontal jump (p=0.001), 10x5 meter sprint (p=0.014), mile run (p=0.001), with the boys presenting better performance in all tests with exception for flexibility (p=0.001). in both boys and girls, the “inhaca” island sample outperformed its mainland peers in the abdominal resistance strength and handgrip strength tests (p=0.001). in the one mile run test the participants from “inhaca” island performed identical to the rural area but better than the urban area (p=0.001). conclusion: school aged children living in the “inhaca” island have a good fitness performance relative to urban peers suggesting an important impact effect of the environment. mailto:nhacagomes@gmail.com o49: associations between body composition, physical activity, intima-media thickness, and cardio-metabolic risk factors in a cohort of teachers: the sabpa-study tamrin veldsman1, mariette swanepoel1, johanna s brits2, makama a monyeki1 physical activity, sport and recreation research focus area (phasrec), faculty of health sciences, north-west university, potchefstroom, south africa1, hypertension in africa research team (hart), north-west university, potchefstroom, south africa2 tamrin.veldsman@nwu.ac.za background: obesity and physical inactivity are linked with high prevalence of non-communicable diseases (ncds) of lifestyle, and ncds are a significant public health concerns in adults; in the 21st century. the study therefore investigated the associations between body composition, physical activity (pa), cardio-metabolic risk factors and carotid intima-media thickness (cimt) in teachers. methodology: a cross-sectional study design; on a data of 216 teachers (104 males; 112 females) from the sympathetic activity and ambulatory blood pressure in africans (sabpa) prospective cohort study from the dr kenneth kaunda district, north west province of south africa was used. body mass index (bmi), waist circumference (wc), waist-to-height ratio (wthr) as measures of body composition, and completed 7-day actiheart pa data according to standard procedures were measured. sonosite micromaxx ultrasound measured cimt. the joint interim statement classifications were applied for metabolic syndrome. the statistical package for social sciences (spss) version 27 analysed the data. results: two thirds of the participants respectively were sedentary and participated in light-intensity pa. twenty-nine percent per cent of the teachers had cardio-metabolic syndrome, and male teachers significantly (p<0.05) had a high mean value for citm. wc positively and significantly (β = 0.151, p = 0.027) related to cimt. in the total sample, a weak significant positive relationship between wc and triglycerides (r = 0.16; p = 0.02) was observed. cimt inversely associated with total energy expenditure (r = -0.31; p = 0.05) in sedentary male teachers. additionally, pa negatively associated with triglycerides (r = -0.29; p = 0.02), gamma-glutamyl transferase (ggt) (r=-0.25; p=0.06). after adjustments for age group, self-reported smoking and alcohol use, a weak significant negative relationship between mean 7-day awake mets and triglycerides (r = 0.28; p < 0.01) remained conclusion: cimt positively associated with wc. participation in light pa associated with lower cimt, triglycerides and ggt. the high cardiovascular risk profile diminished the protective role of pa. physical activity intervention studies are recommended to determine effective interventions to provide information on how to limit the development of atherosclerosis. mailto:tamrin.veldsman@nwu.ac.za o50: physiotherapists’ experiences of rugby-related concussion management in the community marelise badenhorst1, danielle m. salmon2, gisela sole3, simon walters1, johna register-mihalik4, zachary yukio kerr4, john sullivan2, chris whatman1 sports performance research institute new zealand, school of sport and recreation, auckland university of technology, new zealand1, injury prevention and player welfare, new zealand rugby, wellington, new zealand2, centre of health, activity, rehabilitation research, school of physiotherapy, university of otago3, department of exercise and sport science, university of north carolina at chapel hill, chapel hill, usa4 marelise.badenhorst@aut.ac.nz background: new zealand rugby implemented a concussion management pathway to improve concussion management at the community level. physiotherapists often play a key role in the identification, immediateand long-term management of concussions. the aim of this study was to explore physiotherapists’ experiences of rugby-related concussion management, as part of the concussion management pathway, to further inform new zealand rugby’s concussion strategies and subsequently aid future adoption and sustainability. methodology: we adopted a pragmatic, descriptive qualitative approach to explore the perceptions of physiotherapists involved in the pathway. at the end of the 2019 rugby season, semi-structured interviews and focus groups were conducted with twenty-four physiotherapists in three geographically and socioeconomically diverse regions in new zealand (nz). thematic analysis was used to analyse data. results: four themes were identified that play a role in either facilitating optimal concussion management or causing high levels of pressure perceived by physiotherapists. these were: i) ‘walking the tight rope between player welfare and performance’ represented participants' perceptions of the balancing act between different attitudes and priorities of the various rugby stakeholders (whether they prioritised team performance, or player welfare); ii) physiotherapists’ perceptions of their own authority within the team and their concussion management responsibilities; iii) the importance of multidirectional communication in the management of concussion, and iv) the influence of context, which included the complexity of concussion injuries, knowledge of the physiotherapist and team, work-load and resources to support the physiotherapist and ease of access to a medical doctor. conclusion: physiotherapists had positive attitudes toward the concussion management pathway and are well-positioned to play an essential role in this respect. however, strategies are needed to align all stakeholders’ attitudes around player welfare and address persisting challenges. such strategies should also consider experienced physiotherapists mentoring young or inexperienced physiotherapists to improve self-confidence for taking over team roles. the findings of this study also support the value of clear protocols, such as the concussion management pathway, in supporting physiotherapists to deliver effective concussion care. for the pathway’s future sustainability, additional support may be needed to enhance communication between stakeholders, thereby saving valuable time for the physiotherapist and, generally, facilitating the delivery of their duties. mailto:marelise.badenhorst@aut.ac.nz o51: heading exposure in professional football training steve den hollander1, gino kerkhoffs2, 3, vincent gouttebarge1,2, 4 fifpro1, amsterdam umc, university of amsterdam2, achss, amc/vumc ioc research centre3, section sports medicine, up4 steve_dh1989@hotmail.com background: heading the ball has been identified as a risk factor for concussion in association football. however, the exposure to heading, and the g-force of the impacts, are understudied. while ranging from 3.6 (midfielders in ligue 1) to 9.2 (defenders in english championship) per player per match, the number of headers a player makes during training remains unknown. furthermore, self-reported exposure to heading has been shown to be unreliable. therefore, this study aimed to assess the exposure of players to heading in training through objective measures and determine the reliability of self-reported exposure to heading. methodology: sixteen professional footballers took part in a training camp. the camp consisted of 4 training sessions, 2 per day, followed by a match. all training and match sessions were filmed, and the number of headers each player made was noted, retrospectively, by a video analyst. for each observed header, the player who made the header, the intentionality of the header, and the timestamp, were recorded. during all training and match sessions, the players were equipped with an impact tracker, to quantify the g-force of the headers. after each session, the players were asked to recall how many headers they executed during the session. results: players were exposed to 2.2 headers per player per training session, with an average g-force of 15g, and 2.4 headers per play in the match, with an average force of 26g. defenders made more headers in training (n=3.3, g-force=15g) and matches (n=3.8, g-force=19g) than forwards (training: n=2.6, g-force=17g; matches: n=3.0, g-force=34g) and midfielders (training: n=2.6, g-force=20g; matches: n=3.0, g-force=29g) per player per session. 3% of headers were unintentional, with an average g-force of 70g. the reliability of the self-reported exposure to headers was good (intra class coefficient = 0.77). conclusion: players were exposed to fewer headers in training than in the match, with lower impact forces. although defenders made more headers in training and matches, compared to midfielders and forwards, the impact of these headers was less. further research is required to understand the relationships between types of headers, impact forces, and mechanisms of heading related concussions. mailto:steve_dh1989@hotmail.com o52: reporting behaviours and attitudes to concussion among high-school rugby players in kwazulu-natal, south africa johan van heerden1, cameron scullard1, 2 dpt biokinetics, ukzn, south africa1, institute of sports and preventive medicine, saarland university, germany2 vanheerdenj@ukzn.ac.za background: concussion in the sport of rugby has received much attention and many interventions to improve injury identification and management at a professional and semi-professional level. however, there is limited literature into the attitudes, perceptions and motives towards concussion injury acknowledgement and reporting with the high-school rugby population. the popularity of the sport in south-african schools, along with the rapid professional progression of the game at this level, warrants further investigation into determining how players value, or disregard, their safety for the sake of the sport. the aim of the study was to determine the attitudes and perceptions, and reporting behaviours thereof, towards concussion among high-school rugby players. methodology: this descriptive cross-sectional survey comprised of 667 players (average age of 15.4±1. yrs) from kwazulu-natal schools and utilized a modified rocka-st questionnaire which allowed for the formulation of a concussion attitude index (cai) and concussion reporting index (cri). results: less than half (n= 330; 49.5%) of the players reported having previously received concussion education and only 21.4% (p≤0.0001) of their personal knowledge of concussion was rated in the safe category. the players reported a 64.77% rating on the overall cai which indicates a relatively good regard of the risks of concussion, however, the cri revealed a much lower safety rating of 50.4%, and a low (44.1%) score for the attitudinal aspect of the cri, thus reflecting poor reporting behaviours. a large proportion of players (75-91% ) reported that experiencing or reporting a concussion made them feel or look weak and that did not report concussion in fear of letting the team down or missing a subsequent match (66%). conclusion: although being aware of the risks of concussions, players expressed poor self-efficacy in experiencing and reporting concussions, leading to correspondingly poor concussion reporting practices. the majority of the players thus value participation and the risk of losing their place in the team, above their own safety. this ill-conceived loyalty of non-disclosure of concussion being seen as a “badge of honour”, among players, is concerning as it places them at serious shortand long-term risk. mailto:vanheerdenj@ukzn.ac.za o53: injury and illness risk profiles in older active individuals: a systematic review lovemore kunorozva1, phoebe runciman1 institute of sport and exercise medicine (isem), division of orthopaedic surgery, faculty of medicine and health sciences, stellenbosch university, stellenbosch, south africa1 kvnorozwa@gmail.com background: with increased physical activity, the burden of physical activity related injuries and illnesses may increase. yet, only a limited number of studies investigating the epidemiology of illness and injury profiles in older active individuals with disability exist. methodology: a comprehensive literature search of injury and illness risk profiles in older active individuals with and without a disability was conducted employing pubmed, ebscohost and web of science databases up to 31 july 2021. each of the articles was independently reviewed for relevance and inclusionary criteria, with 11 studies meeting these criteria. results: overall, the quality of the included studies was excellent. respiratory, skin and sub-cutaneous, and digestive system illnesses were the commonly reported illnesses. chronic overuse injuries in the upper extremities including shoulders (32%), chest (13%) and elbow (13%) were frequently reported. sport and/or impairment type were the most frequently reported contributor to injury. conclusion: the findings of this review indicate that: 1) sport and/or impairment type are the main contributors to both injury and illness and not age or sex; although older individuals exhibited a higher prevalence of chronic overuse injuries; and 2) older individuals have a slightly higher risk of developing illnesses, with respiratory, skin and sub-cutaneous, as well as digestive system illnesses most common. there is a need for further research on injury and/or illness profiles in older individuals, as this would allow clinicians to provide better rehabilitative and pre-habilitative care. additionally, this would provide important information on predicting illness and injury risks and help further develop preventative strategies. mailto:kvnorozwa@gmail.com clinical case presentations c01: compete androgen insensitivity syndrome: an ongoing competition regulations, ethics and fairness dilemma lone bogwasi1 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa, caf medical committee member, botswana football association medical committee member1 history: 23/f football athlete identified on routine pre-competition medical screening and sex testing (gender verification). background: primary amenorrhea, hoarseness of voice, no hirsutism investigated for eligibility to compete in a female football continental competition physical findings: lean built and ectomorph structure. weight: 45.3 kg height: 167cm bmi: 16.2 body fat: 14.8% muscle mass: 36.6 kg bone mass: 2 kg physique rating: 7 hoarse voice, no hirsutism, flat forehead, prominent cheek bone (zygomatic bones). small breasts (almost flat chest) female genitalia, large labia and clitoris slightly larger than normal. small palpable masses on b/l inguinal area differential diagnosis / hypothesis: sexual ambiguity test and results: testosterone levels: 24/09/2021 43ng/l 02/2022 39ng/l fsh: 84.18 mlu/ml lh: 5.10 mlu/ml progesterone: 1.19ng/ml 17b oestradiol: 139.19 pmol/l prolactin 13.20ng/ml chromosomal analysis: xy genotype, no gross structural abnormalities ultrasound scan findings: the uterus could not be exclusively identified on sonar. no fluid collection seen in the pelvis. there are no obvious pelvic masses or cysts seen. urinary bladder well distended with a normal outline and no masses. mri scan findings: liver, biliary system, spleen, kidneys all normal. normal stomach, bowel loops and rectum. no intrabdominal lymphadenopathy. a phallus is presently attached to ischiopubic rami. this appears indeterminate between a micropenis and an unusually enlarged clitoris. the vagina cervix and uterus are not visualized. the prostate is not visualized, uterus and ovaries not visualized. no testis is seen. no fluid in cul-de-sac. no significant inguinal lymphadenopathy. no sizeable hernia noted. final/working diagnosis: complete androgen insensitivity syndrome treatment and outcomes: based on the outcome of cais. she was referred to an endocrinologist who suggested the testosterone level although high does not offer any athletic advantage. the competition rules for caf/fifa women football do not make her eligible to participate. the regulations are for female vs female and male vs male participation. the options for intervention include: 1. surgery (removal of undescended testes) 2. hormonal therapy 3. maintain hormonal levels for a female current treatment plan: 1. the sad news was broken to her and the athlete was informed about the finding and then taken through the available options and side effects. currently, she is thinking through the options and hasn't made a decision yet. 2. continued psychotherapy in place 3. gynaecologist and surgical reviews once she decides on the operative route (she was also made aware of the risk of cancer from undescended testes). 4. endocrinologist follow-up sessions 5. dietician a further treatment plan will be based on her decision. c02: exertional cardiopulmonary symptoms following viral urti’s – take it to heart marcel jooste1 sport exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria1 history: a 17-year-old national level athlete, with no comorbidities, presented with complaints of persistent, exertional cardiopulmonary symptoms 7 weeks following a suspected viral acute respiratory infection (arinf) during the acute phase on the infection, she experienced symptoms confined to the upper respiratory tract, she was treated as presumed sars-cov-2 infection based on symptoms without a confirmatory nasopharyngeal swab. she continued to train during the symptomatic phase of infection. one month after the arinf she started experiencing sharp, exertional chest pain, excessive fatigue during exercise, and an elevated resting heart rate. these symptoms persisted despite resting from exercise for 3 weeks, which led her to seek further medical advice. the patient denied any significant psychosocial stressors during this time. she had no family history of cardiovascular disease. physical findings: vital signs: hr 71, bp 129/80, rr 12, sats 99%. general examination was normal. cardiovascular examination revealed no evidence of a murmur even with dynamic movements, no pericardial rub nor any signs of oedema. all distal pulses were equal with normal rhythm, no radio-femoral delay. respiratory examination was normal with no pain with inspiration, nor tenderness to palpation of the costochondral junctions. otolaryngological and abdominal examinations did not reveal any significant findings. differential diagnosis / hypothesis: costochondritis viral myocarditis viral pericarditis anxiety pulmonary embolism arrythmia test and results: bloods: fbc = normal crp = 1 mg/l esr = 4 mm/hr hs troponin t = <5 tsh = 1.35 miu/l t4 = 11.3 pmol/l ferritin = 21 ng/ml resting ecg: hr 71 sinus arrythmia. widespread st elevation involving the inferolateral leads with reciprocal pr segment depression in the inferior leads. down-sloping t-p segment (spodick sign) in the inferior leads. echocardiogram: normal cardiac mri: normal heart size and function. mild pericardial enhancement of the surface overlying the anterior as well as left ventricle free wall, suggestive of pericarditis changes. no discrete pericardial effusion or thickening could be noted. final/working diagnosis: subacute viral pericarditis treatment and outcomes: a stress ecg was performed to assess the physiological response to limited exercise. there was a blunted systolic blood pressure response to exercise, normal heart rate recovery, no arrythmias, no stsegment changes with exercise. the patient was counselled on the prognosis and risks of strenuous exercise during active phase of the condition. she was started on ibuprofen and colchicine. recommendation was to rest and perform only light-intensity exercise for one month until follow-up consultation. if asymptomatic at follow-up, then to perform limited stress ecg. c03: vertigo in a hockey player jo-anne kirby1 stellenbosch university1 history: a 21-year-old collegiate field hockey player developed vertigo during an international tournament. at first, she felt dizzy and faint but then it became rotational vertigo which would last 1s and come back approximately every 30s during and after exercise. she had no ear pain or hearing loss but on initial evaluation had redness of the ear, otitis was suspected and she was placed on antibiotics and anti-virals. she continued to play. at another tournament, she began vomiting. in addition to vertigo, she was now unable to run in a straight line after a direction change and had difficulty seeing the ball approach. despite this, she continued to play in a series of tournaments. she felt as though she was adapting, the vertigo was reducing but was replaced by headaches and altered hearing. physical findings: on clinical examination she had horizontal nystagmus in both eyes, normal eye movements and normal neurological and cardiovascular examinations. she had redness of the tympanum at her first examination cleared on follow-up differential diagnosis / hypothesis: otitis media / interna vertigo of peripheral origin e.g. bppv vertigo of central origin concussion test and results: brain mri revealed a well-defined, lobulated right cerebro-pontine angle mass lesion with internal inhomogeneity with a significant mass effect on the brain stem, which is deviated to the left and a subtle mass effect and encasement of the associated cranial nerves. final/working diagnosis: intracranial epidermoid cyst with an incidental finding of a cystic lesion within/in close association with the posterior pituitary. treatment and outcomes: this was surgically removed leaving 10% of the lining in areas of critical structures. six weeks later she returned to academic activities. rehabilitation started with neck range of movement exercises followed by strengthening and running. she returned to competitive sport by the end of the season and has been asymptomatic since. c04: pericarditis viral enteritis or covid19 to blame? lervasen pillay1 university of pretoria, university of witwatersrand, university of amsterdam1 history: the patient presented with a viral bout of diarrhoea in december 2020. covid19 infection was excluded and treated with probiotics and anti-diarrhoea medication. there were no complications and the athlete returned to activity as soon as the symptoms settled. upon return, palpitations on exertion (very occasional) were noted but ignored. a diagnosis of covid19 was made 5 months later (after having symptoms for 5 days which included loss of taste, fever, sore throat and slight cough). this was treated symptomatically and settled uneventfully. however, the palpitations worsened. as per team protocol, the patient presented for a post covid19 infection medical clearance. physical findings: initial clinical evaluation revealed normal vitals pulse rate of 65/min, bp 110/72, o2 saturations 98% on room air. there was a pericardial rub. the rest ecg revealed a right bundle branch block. due to clinical findings, blood tests were done and a referral to a sports cardiologist. differential diagnosis / hypothesis: pericarditis/myocarditis test and results: u and e, ckmb, fbc, crp, trop-t were all normal. cardiac echo revealed a mild pericardial effusion with no tamponade. left ventricle ejection fraction was 56% and there were no abnormal wall movements. contrast cardiac mri revealed a 4 4.5mm pericardial effusion and post-contrast pericardial enhancement confirming inflammatory pericarditis. final/working diagnosis: pericarditis treatment and outcomes: the patient refrained from moderate to high-intensity exertional activity for 3 months. medical treatment consisted of colchicine 0.5mg daily and ibuprofen 200mg bd for 3 months. medication was adjusted according to any side effects experienced. a cardiologist review was done after 3 months and was given the clearance to return to sport. a progressive return to play sport-specific conditioning program was implemented and returned to full activity after 6 weeks. there have been no further complaints. in light of covid19 and the recent highlight on cardiac inflammation, it is important for clinicians to be reminded that cardiac inflammatory conditions can also be caused by other viral infections. c05: "back to basics": spinal pain in a recreational runner karen schwabe1 stellenbosch university1 history: this is a case presentation of an 81-year-old recreational male runner, who was in training for an international 5 km race. he was previously well, with no known underlying diseases. he sustained an injury of the thoracic spine in the gym with weight training. initially, he consulted his gp about this injury, who diagnosed musculoskeletal back pain. at that stage, basic bloods and an xr of the thoracic spine were done, which were all normal. he was treated with nsaim and advised to rest. initially, he responded to rest and the medication, but the pain recurred. subsequently, he was referred to a physiotherapist, with variable response. after a month, the pain increased, with the patient now experiencing night pain, but no other systemic symptoms. he was booked to see a neurosurgeon at this point. whilst waiting for the appointment, he developed intractable back pain and weakness and numbness of the lower limbs as an acute episode. at this point, he presented to the emergency department. physical findings: initially: central back pain level t3. neurologically intact er: level t3 motoric and sensory fall-out, progressing, with urinary retention and no rectal tonus. differential diagnosis / hypothesis: musculoskeletal back pain secondary to a gym injury thoracic disc disease infection neoplastic test and results: cxr: initial normal (dec 2021) fbc: initial normal (dec 2021) mri: t3 vertebral collapse with cord compression (jan 2022) ct chest: bilateral pleural effusions, multiple pulmonary nodules bilateral, small pericardial effusion gastroscopy: biopsy adenocarcinoma final/working diagnosis: metastatic spinal cord (t3) disease with vertebral collapse and complete motoric and sensory fall-out at this level. treatment and outcomes: emergency decompression at level t3 and surgical screws t2 & t4 radiation therapy 10 sessions (colon) chemotherapy step-down rehab facility c06: an unusual case of a femoral bone stress injury in a high school female hockey player karen schwabe1 stellenbosch university1 history: a 17-year-old female hockey player, sustained an injury to the left upper leg during a hockey tournament. she fell onto the right hip and injured left upper leg/felt a 'pull' in the proximal-medial area of the groin. she continued to play 'through' the pain for the rest of the game but did not participate further in the tournament games due to the discomfort. she consulted a sports physician 5 days later. clinically a grade 1 left adductor brevis was diagnosed and an ultrasound confirmed a proximal adductor strain. the pelvis xr was normal. at this point she was referred for physiotherapy rehabilitation, rest and to use of 1 crutch. after 10 days there was no clinical or functional improvement and her pain in weight bearing increased. further re-evaluation now showed bony pain of the left proximal femur and she was referred for a mri scan. the mri revealed extensive bone stress injury of the proximal shaft of the left femur. she was previously healthy with no known medical diseases and no significant previous injuries. vegetarian physical findings: initial consultation: grade 1 left sided adductor tear follow-up consultation: bony pain on the femoral shaft (with improvement on the adductor strength). inability to now weight-bear without pain. antalgic gait. differential diagnosis / hypothesis: adductor tear avulsion injury referred pain from the hip/labral pathology pelvic/femoral bone stress test and results: pelvis xr: normal ultrasound left groin: mri pelvis: significant bone stress injury involving the subtrochanteric proximal shaft of the left femur, fredrickson grade 4a. bilateral acute iliopsoas musculotendinous strain patterns. subtle common adductor insertional tendinopathy with no evidence of associated tear. bloods: parathyroid hormone:low normal, vitamin d: low normal ferritin, fbc, u&e, vit b12, tsh, mg2+, po4-, ca2+ all normal. final/working diagnosis: severe overuse bone stress injury of the proximal femur (red-s not suspected) treatment and outcomes: current treatment: non-weight-bearing, vit d supplementation, physiotherapy future treatment plan: 3 months of partial weight-bearing, then gradual post loading and stretching. after 3 months of gradual functional strength training and field work depending on progress. recheck the pth and vit d levels at 3 months dietician referral as the patient is a vegetarian *clinical response yet to be determined original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license self-compassion mediates the relationship between dispositional mindfulness and athlete burnout among adolescent squash players in south africa sp walker, phd department of psychology, university of the free state, bloemfontein, south africa corresponding author: sp walker (walkersp@ufs.ac.za) athlete burnout (abo) is a multifaceted phenomenon characterised by physical and/or mental exhaustion, a reduced sense of accomplishment from participating in sport, and a tendency to devalue the role of sport in the individual’s life.[1] the demands placed upon adolescent athletes with respect to education, peer relationships, identity development, training and competition, as well as satisfying parental and coaching expectations puts this population at risk for abo.[2] abo is associated with short-term performance and mental health costs, as well as a reduction in lifetime physical activity. [3] consequently, psychological processes implicated in the development and modulation of abo among adolescent athletes warrant greater research attention. evidence of an inverse relationship between dispositional mindfulness (dm) and abo continues to mount across athlete populations.[4] dm, a relatively stable awareness of the present moment, is characterised by acceptance and non-judgement towards internal experience and external stimuli, and is increasingly being shown to positively impact athletic performance and emotional well-being among athletes.[5] dm is viewed as being primarily trait-like and is often differentiated from cultivated mindfulness, which is the state more commonly associated with mindfulness training and meditation practice.[5] despite the connection between dm and abo, little is known about the psychological processes by which dm might impact abo. it has been hypothesised that dm may enhance athlete performance and well-being through increased task-focussed attention, greater acceptance of external influences and internal experiences, more effective emotional regulation, a reduced tendency to ruminate and the facilitation of psychological flexibility.[6] however, this is based almost exclusively on data from clinical and non-athlete populations. self-compassion (sc) has been proposed as a possible mechanism that might augment or modulate the impact of dm on psychological well-being in the general population.[7] sc is broadly conceptualised as an attitude towards the self that is characterised by the absence of self-judgement, self-kindness, a sense of connection with others based on common human experiences, and a mindful orientation towards events and experiences.[8] within the sporting realm, sc has been associated with improved psychological well-being and an increase in perceived performance among canadian female collegiate athletes.[9] it has also been suggested that sc may augment and/or modulate the interaction between dm and abo. a recent study found that both sc and dm were inversely related to abo among japanese collegiate athletes.[10] sc partially mediated the relationship between dm and abo only among female participants. while dm was directly associated with sc and negatively related to abo in the male participants, sc was not directly associated with abo in these participants [10]. in addition, female athletes reported lower levels of dm and sc compared to their male counterparts.[10] higher levels of dm appear to be associated with reduced abo among athletes.[4] a recent study reported sc as a potential mechanism that might mediate this relationship.[10] however, the study was conducted among young adult collegiate athletes. consequently, the current study aims to background: dispositional mindfulness has been found to positively impact athlete burnout. furthermore, selfcompassion has been identified as a potential mechanism of action through which mindfulness is related to lower rates of athlete burnout. however, this interaction has yet to be investigated among adolescents. objectives: to determine whether self-compassion mediates the relationship between dispositional mindfulness and athlete burnout among adolescent squash players in south africa. methods: competitive adolescent squash players (n=158) from two provinces in south africa completed measures of dispositional mindfulness, self-compassion and athlete burnout. intercorrelations were calculated between the three variables. an ordinary least squares regression analysis was performed to test the indirect effect of self-compassion on the relationship between dispositional mindfulness and the three components of athlete burnout. results: both dispositional mindfulness and self-compassion were negatively related to athlete burnout, while displaying positive correlations with each other. self-compassion was found to partially mediate the relationship between dispositional mindfulness and a sense of reduced accomplishment (b = -0.075; 95% ci [-0.037;-0.012]), as well as the association between dispositional mindfulness and sport devaluation (b = -0.056; 95% ci [-0.099;-0.022]). the relationship between dispositional mindfulness and exhaustion was, however, not mediated by self-compassion (b = -0.002; 95% ci [-0.052; 0.049]). conclusion: the effect of dispositional mindfulness on certain components of athlete burnout is partially mediated by selfcompassion among adolescent athletes. based on the current findings, interventions aimed at increasing mindfulness among adolescent athletes appear to be a potential avenue by which to reduce certain aspects of burnout, partially through increasing self-compassion. keywords: reduced accomplishment, sport devaluation, youth athletes, mediation s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a11877 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a11877 https://orcid.org/0000-0002-2110-7881 original research sajsm vol. 33 no. 1 2021 2 determine whether sc mediates the relationship between dm and abo among adolescent athletes. methods participants ethics approval was granted by the general human research ethics committee at the university of the free state (ufshsd2019/063/1007) for this study. permission to collect data at south african schools squash tournaments held in two provinces was obtained from the relevant national and regional governing bodies. all 18-year-old participants, as well as the guardians of minors, provided written informed consent. the written assent of all minors was also obtained. data were collected by means of paper-and-pencil versions of the questionnaires. all questionnaires were administered in english. participants completed these questionnaires either after practice sessions or between matches at tournaments. data collection was conducted in cooperation with participants and their coaches to ensure minimal disruption of training and competition. one hundred and fifty-eight adolescent squash players (males = 108; females = 50) participated in the study. participants ranged in age from 13 to 18 years (m = 15.4 years; sd ± 1.2). athletes reported having played squash competitively for an average of 3.9 years (sd ± 2.8). at the time the data were collected, participants were practicing an average of 4.94 hours (sd ± 3.01) per week. the majority (56%) indicated representing their school as their highest level of participation, while 35% competed at provincial level and 10% reported being ranked among the top 10 players in their age group nationally. measures it is recommended that a multidimensional approach to measuring abo be adopted in research.[2] consequently, the reduced sense of athletic accomplishment (ra), physical and emotional exhaustion (e) and sport devaluation (d) subscales of the athlete burnout questionnaire (abq) were employed instead of the total score.[1] each subscale is comprised of five items. response options ranging from “almost never” to “almost always” are presented along a five-point likert-type scale. scores for each subscale are calculated by summing responses across the five items comprising the respective subscales, with higher scores indicating greater burnout. the abq total score has demonstrated good reliability in a sample of adolescent south african tennis players.[11] however, no local data are available with respect to the psychometric properties of the subscales. dm was measured using the child and adolescent mindfulness measure (camm).[12] the camm is a 10item self-report inventory that yields a unitary mindfulness score, with higher scores indicating increased levels of dm. response options ranging from “never true” to “always true” are presented along a fivepoint likert-type scale. adequate internal consistency has been reported for the camm in a sample of female adolescent hockey players in south africa.[13] the short form of the self-compassion scale (scs-sf) was employed to measure sc.[14] participants are required to respond to 12 items along a five-point likert-type scale, with endorsement options anchored by “almost never” and “almost always”. after reverse scoring the negatively worded items, a total sc score is obtained by summing responses across all 12 items. higher scores are indicative of a greater degree of sc. while no psychometric data could be found with respect to the scs-sf in adolescent athlete samples, the original version of the scs, from which the scs-sf is derived, has demonstrated good internal consistency in a sample of non-athlete adolescents.[15] statistical analysis internal consistency coefficients were calculated for all variables included in the study. correlations between the abq subscales, camm and the scs-sf were then calculated. based on previous findings of a potential gender difference with respect to levels of abo, sc and dm among athletes, a between-groups multivariate analysis of variance (manova) was conducted to explore possible gender differences within the current sample.[10] finally, as it was hypothesised that sc would mediate (indirect effect) the direct effect of dm on abo (see figs. 1 to 3), a mediation analysis was conducted to test for the effect of sc on the relationship between dm and abo. this was achieved through a path analytic approach employing ordinary least squares (ols) regression analysis.[16] the ols regression analysis was performed using the process software macro for spss.[16] a nonparametric bootstrapping method was employed to test for the statistical significance of the cross product of coefficients. consequently, no assumptions needed to be made with respect to the distribution of abq, camm and scs-sf scores in the sample. the regressions model was computed across 5 000 simulations utilising biascorrected bootstrap procedures. the statistical significance of the indirect effects was determined using a 95% confidence interval.[16] analyses were conducted independently for each of the three subcomponents of abo. results table 1 reflects the correlations between the abq subscales, table 1. correlations, reliability coefficients and descriptive statistics for the study variables (n=158) variables camm scs-sf abq-ra abq-e abq-d camm 0.369** -0.220** 0.317** -0.266** scs-sf -0.431** -0.127 -0.339** abq-ra 0.172* 0.481** abq-e 0.505** α 0.750 0.794 0.679 0.872 0.739 m 21.45 39.39 11.96 9.72 8.57 sd 6.31 7.58 3.23 4.02 3.44 ** indicates p < 0.01; * indicates p < 0.05. m, mean; sd, standard deviation; camm, child and adolescent mindfulness measure; scs-sf, self-compassion scale – short form; abq-ra, athlete burnout questionnaire – reduced sense of athletic accomplishment; abq-e, athlete burnout questionnaire – physical and emotional exhaustion; abq-d, athlete burnout questionnaire – sport devaluation. original research 3 sajsm vol. 33 no. 1 2021 camm and scs-sf. mean scores, standard deviations (sds) and internal consistency coefficients are also reported for each measure. it is apparent that internal consistency coefficients for all measures, with the exception of the abq-ra subscale (α = 0.68), meet the prescribed minimum level of acceptability for non-cognitive measures (α ≥ 0.70).[17] given how close this internal consistency coefficient is to satisfying the criterion, the abq-ra subscale was included in the subsequent analyses. all variables were statistically significantly correlated, except for the abq-e subscale and scs-sf. the abq subscales demonstrated negative relationships with both the camm and scssf, while the camm and scs-sf were positively correlated. a manova was conducted to test for the effect of gender on dm, sc and the three components of abo. gender (female/male) served as the independent variable, while the abq-ra, abq-e, abq-d, camm and scs-sf functioned as dependent variables. preliminary assumption testing indicated no violations with respect to normality, linearity, univariate and multivariate outliers, homogeneity of fig. 1. the mediating effect of self-compassion in the relationship between dispositional mindfulness and reduced sense of athletic accomplishment. all presented effects are unstandardised: a is effect of dispositional mindfulness on self-compassion; b is effect of self-compassion on reduced sense of athletic accomplishment; c’ is direct effect of dispositional mindfulness on reduced sense of athletic accomplishment; c is total effect of dispositional mindfulness on reduced sense of athletic accomplishment. fig. 2. the mediating effect of self-compassion in the relationship between dispositional mindfulness and physical and mental exhaustion. all presented effects are unstandardised: a is effect of dispositional mindfulness on selfcompassion; b is effect of self-compassion on physical and mental exhaustion; c’ is direct effect of dispositional mindfulness on physical and mental exhaustion; c is total effect of dispositional mindfulness on physical and mental exhaustion. fig. 3. the mediating effect of self-compassion in the relationship between dispositional mindfulness and sport devaluation. all presented effects are unstandardised: a is effect of dispositional mindfulness on self-compassion; b is effect of self-compassion on sport devaluation; c’ is direct effect of dispositional mindfulness on sport devaluation; c is total effect of dispositional mindfulness on sport devaluation. original research sajsm vol. 33 no. 1 2021 4 variance, and multicollinearity. no significant differences were found between the female and male respondents with respect to the combined dependent variables f (5;148) = 1.150, p = 0.337, partial eta squared = 0.037. mediation analyses were conducted to test the direct and indirect (via sc) effects of dm on the three components of abo. in each case, the proposed mediator (sc) was regressed on dm (path a), while the relevant component of abo was regressed on sc (path b) and dm (path c’). fig. 1 illustrates that dm is indirectly related to abq-ra through sc. dm is associated with an increase in sc (a = 0.454, p < 0.001), and a decrease in abq-ra is related to sc (b = 0.166, p < 0.001). a bias-corrected confidence interval based on 5 000 bootstrap samples indicates that the indirect effect (ab = -0.075) falls within a range that does not include zero (-0.037 to -0.012). fig. 1 also indicates that the direct effect of dm on abq-ra is no longer statistically significant once the indirect effect of dm via sc is considered (c’ = -0.032, p = 0.421). in combination, dm and sc explain 18.3% (f(2;153) = 17.107, p < 0.001) of the variance in the participants’ abq-ra scores. the mediation analysis depicted in fig. 2 indicates that dm is not indirectly associated with abq-e through sc. dm is related to an increase in sc (a = 0.455, p < 0.001). however, sc does not result in a significant change in abq-e (b = -0.004, p = 0.924). a 95% bias-corrected confidence interval based on 5 000 bootstrap samples indicates that the indirect effect (ab = 0.002) falls within a range that includes zero (-0.052 to 0.049). moreover, the direct effect of dm on exhaustion remains statistically significant once the indirect effect of dm through sc is considered (c’ = -0.199, p < 0.001). furthermore, dm and sc together account for 9.7% (f(2;152) = 8.157, p < 0.001) of the variance in the sample’s abq-e scores. fig. 3 indicates that dm has an indirect effect on abq-d through sc. dm is associated with an increase in sc (a = 0.447, p < 0.001), and a reduction in abq-d is related to sc (b = 0.126, p = 0.001). a bias-corrected confidence interval based on 5 000 bootstrap samples indicates that the indirect effect (ab = -0.056) falls within a range that does not include zero (-0.099 to -0.022). it is further evident from fig. 3 that the direct effect of dm on abq-d is no longer statistically significant once the indirect effect of dm via sc is considered (c’ = -0.085, p = 0.061). the combination of dm and sc explains 13.3% (f(2;151) = 11.582, p < 0.001) of the variance in the participants’ abq-d scores. discussion the current study aimed to contribute to the growing literature on the mechanisms of mindfulness in sport psychology, specifically by exploring the extent to which sc mediates the interaction between dm and components of abo among adolescent athletes. dm demonstrated negative correlations with all three components of abo. this finding is in line with the increasing evidence of the inverse relationship between dm and abo in athlete populations. [4, 10-11] however, the current findings expand on existing research within the south african context by establishing that all three components of abo demonstrate significant negative relationships to dm. this strengthens the case for focussing on dm as an important psychological construct in understanding abo among adolescent athletes. sc was positively associated with dm. this is in keeping with the prevailing opinion in the mindfulness and clinical literature that dm and sc seem to be conceptually and functionally related processes.[7-8] findings from the current study suggest that the relationship between sc and abo might be somewhat more complex. sc was negatively associated with a reduced sense of athletic accomplishment and the sport devaluation components of abo. however, no significant correlation was found between sc and the physical and emotional exhaustion (exhaustion) component of abo. to date, only one other study appears to have directly explored the relationship between sc and abo in an athlete population.[10] here significant relationships were found between sc and all components of abo. it is important to note that the aforementioned study was conducted among athletes in a different cultural context and developmental stage than that of the participants in the current study. in addition, athletes in the two studies differed with respect to the sporting codes represented and level of competition. consequently, findings with respect to the interaction between sc and exhaustion might be more reflective of the training load associated with a specific sport and/or level of competition. further research is thus required before general conclusions can be drawn with respect to the exact relationship between sc and exhaustion. in the current sample, sc was found to partially mediate the interaction between dm and a reduced sense of athletic accomplishment, as well as the interaction between dm and sport devaluation. consequently, an increase in dm was related to greater sc, which was in turn associated with less of a sense of reduced athletic accomplishment and lower levels of sport devaluation among the participants. however, sc did not mediate the interaction between dm and exhaustion. similarly, sc accounted for more of the variance in both the sense of reduced athletic accomplishment and sport devaluation when compared to dm, while dm accounted for more of the variance in exhaustion than did sc. therefore, sc may be more salient to self-critical and evaluative cognitive processes involved in abo, while being less relevant to somatic and intuitive components of abo. a sense of reduced athletic accomplishment is, at least partially, based on the subjective evaluation of the athlete’s current performance compared to their performance goals and/or the performance of other athletes.[1,3] in a similar way, sport devaluation necessitates some form of cost-benefit analysis with regard to other aspects of the athlete’s life.[1-3] it stands to reason that self-acceptance and self-kindness, as manifested in sc, would potentially undermine self-criticism and thus contribute to a lesser sense of reduced athletic accomplishment.[7-9] similarly, the value clarification, selfacceptance and sense of connection to others encompassed in sc would be expected to reduce the risk that adolescent athletes would devalue the role of sport in their lives.[3, 7-9] experiential acceptance, psychological flexibility, clarity regarding values, non-attachment and a reduced tendency to ruminate have been proposed as mechanisms via which mindfulness might original research 5 sajsm vol. 33 no. 1 2021 facilitate athletic performance and athlete well-being.[6] the similarity between these processes and those attributed to sc might provide insight into the manner in which sc mediated the impact of dm on a reduced sense of athletic accomplishment and sport devaluation in this study. while further research is required, it could be hypothesised that specific qualities or characteristics of mindfulness promote self-kindness and/or undermine self-criticism which, in turn, partially negates a sense of reduced athletic accomplishment and sport devaluation among adolescents. the experience of physical and mental exhaustion within the context of abo is conceivably less dependent upon evaluative cognitive processes or self-criticism. mindfulness mechanisms, such as bare attention, as well as clarity with respect to physical sensations and internal experiences, are arguably more relevant to the experience of exhaustion.[6] the finding that dm was associated with exhaustion, while sc was not associated with this component of abo nor mediated its relationship to dm is thus not surprising. it could be speculated that sc does not have the same impact on exhaustion as it does on the other two aspects of abo. however, adolescents competing in ball sports have been found to be at comparatively lower risk for abo in relation to those involved in endurance, aesthetic, highly technical or weight-dependent sports.[2] moreover, few participants in this study compete at a particularly high level and most report low to moderate training loads. consequently, findings related to exhaustion and sc or dm in this study should be interpreted circumspectly. limitations the study made use of a small sample of adolescents participating in one sport. consequently, the reported findings cannot be generalised beyond adolescent athletes. nor should they be extrapolated to other sporting contexts, particularly team sports or sporting codes that emphasise endurance, aesthetic performance, or require high levels of technical ability. there is a need for replication of this research in more varied athlete populations. future research should explore the interrelationships between abo, dm and sc across various sporting codes and contexts, as well as in a number of developmental stages and at different levels of competition. to date, most of the research on sc within the sporting context has been conducted among female athletes. furthermore, a recent study on abo found differences between males and females with respect to sc and the mediation of the dm/abo relationship by sc.[10] the current study yielded no gender differences. however, given the small number of female participants, these findings should not be viewed as representative. additional research is required to establish whether consistent gender differences are apparent with respect to abo, dm and sc, as well as exploring the specific nature and possible effects of such differences. the regression models tested in this study indicate that dm and sc explain only a small to moderate proportion of the variance in abo among adolescent athletes. moreover, where sc mediates the interaction between dm and abo, this effect is only partial. dm and sc are thus not the only predictors of abo, and sc is not the sole mediator of the effect of dm on abo. more work is required to identify other predictors, as well as additional mediators and moderators with respect to the dm, sc and abo relationship. the current study employed a cross-sectional correlation design. consequently, conclusions can only be drawn with respect to temporal and correlational relationships of the study variables to one another. longitudinal studies are required to better understand the effect of incremental and developmental influences on the interaction between dm, sc and abo. experimental studies would be beneficial in two respects. firstly, they would be better suited to exploring issues of causality with respect to the effects of dm and sc on abo. secondly, controlled experiments would allow for a more finegrained examination of the mechanisms by which dm might influence athletic performance and athlete well-being. conclusion dm is significantly related to lower levels of abo among adolescent athletes. however, sc appears to only be associated with a reduction in two components of abo. sc partially mediates the interaction between dm and a reduced sense of athletic accomplishment, as well as the interaction between dm and sport devaluation. sc does not impact the relationship between dm and exhaustion. mindfulness practices continue to hold promise in preventing and reducing abo. however, based on the current study, the potential for tailored mindfulness interventions targeting specific components of abo via sc should be explored further. conflict of interest and source of funding: the author declares no conflict of interest and no source of funding. references 1. raedeke td, smith al. development and preliminary validation of an athlete burnout measure. j sport exerc psychol 2001;23(4):281-306. [doi: 10.1123/jsep.23.4.281] [pmid: 28682196] 2. granz hl, schnell a, mayer j, et al. risk profiles for athlete burnout in adolescent athletes: a classification analysis. psychol sport exerc 2019:41(1), 130-141. [doi:10.1016/j.psychsport.2018.11.005] 3. isoard-gautheur s, guillet-descas, e, gustafasson h. athlete burnout and the risk of dropout among young elite handball players. sport psychol 2016:30(2), 123-130. [doi:10.1123/tsp.2014-0140] 4. li c, zhu y, zhang m, et al. mindfulness and athlete burnout: a systematic review and meta-analysis. int j environ res public health 2019;16(3):449. [doi:10.3390/ijerph16030449] [pmid: 30717450] 5. rau hk, williams pg. dispositional mindfulness: a critical review of construct validation research. pers individ differ 2016;93(1):32-43. [doi:10.1016/j.paid.2015.09.035] 6. birrer d, röthlin p, morgan g. mindfulness to enhance athletic performance: theoretical considerations and possible impact mechanisms. mindfulness 2012;3(3):235-246. 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[doi:10.7196/sajsm.498] 12. greco la. baer ra, smith gt. assessing mindfulness in children and adolescents: development and validation of the child and adolescent mindfulness measure (camm). psychol assess 2011;23(3):606-614. [doi:10.1037/a0022819] [pmid: 21480722] 13. walker sp. mindfulness and mental toughness among provincial adolescent female hockey players. s afr j sport med 2016;28(2):46-50. [doi:10.17159-516x/2016/v28i2a1110] 14. raes f, pommier e, neff k.d, et al. construction and factorial validation of a short form of the self-compassion scale. clin psychol psychother 2011;18(3):250-255. [doi:10.1002/cpp.702] [pmid: 21584907] 15. cunha m, xavier a, castilho p. understanding selfcompassion in adolescents: validation study of the selfcompassion scale. pers individ differ 2016;93(1):56-62. [doi:10.1016/j.paid.2015.09.023] 16. hayes af. introduction to mediation, moderation, and conditional process analysis: a regression-based approach. new york: guilford press, 2013. 17. foster jj, parker i. carrying out investigations in psychology: methods and statistics. leicester: willey blackwell, 1995. jsm0404pg000ed. introduction the most common reason for absence from training in elite sportsmen is the presence of upper respiratory tract infections, followed by acute and chronic injuries. (berglund and hemmingson 2) in 1983 professor eric bateman and i described an increased prevalence of self-reported symptoms of upper respiratory tract ‘infections’ following participation in a 56 km ultramarathon in runners when compared with the prevalence in matched non-running, sedentary controls during the same time period.58 both runners and controls had reported the incidence of runny noses, sneezing, sore throats and coughs with or without accompanying fever, immediately before and during the 2 weeks following the 1982 two oceans ultramarathon. the incidence of these self-reported symptoms was found to be significantly higher in runners than in controls and the post-race symptoms highest amongst the runners who ran the fastest.58 this finding has been repeated numerous times, both in south africa and abroad.33,44,46,59 research focus in the rapidly developing field of exercise immunology has subsequently been placed on identifying: (i) the mechanisms which possibly result in this high prevalence of ‘infection’ during the postrace period; and (ii) nutritional and pharmacological intervention strategies in an attempt to reduce the higher ‘infection’ risk experienced by ultradistance athletes during the 3 72 hour post-event ‘open-window’ period (fig. 1) and during periods of excessive training. during the last 25 years, no less than 1 500 studies have been published in this relasports medicine vol 16 no.1 2004 3 review article postrace upper respiratory tract ‘infections’ in ultramarathoners — infection, allergy or inflammation? e m peters (ba (hons), bsc(med) hons, msc(med), phd) department of physiololgy, nelson r mandela school of medicine, university of kwazulu-natal, durban abstract despite more than 20 years of research into mechanisms which could result in the increased predisposition of athletes to ‘infection’ incidence following excessive and prolonged exercise, definitive explanations are not yet available. a strong temporal relationship between the incidence of upper respiratory tract infection symptoms and immune system changes following excessive exercise load (eel) have not been shown. t-helper cells are functionally polarised according to the cytokines which they produce. while exercise-induced upregulation of t-helper2 (th2) cells and type 2 cytokines is indicative of enhanced activation of allergic responses, downregulation of t-helper-1 (th1) cells and type 1 cytokines confirms suppression of cellular immune functions. the current knowledge regarding the exercise-induced kinetics of interleukin (il)-4, a cytokine that is crucial in the activation of the th2 cells, does, however, not appear to provide sufficient support for an upregulation of a type 2 response. lowered or unchanged circulating concentrations of type1 cytokines (il12, il-2 and interferon γ) and short-term suppression of lymphocyte, natural killer cell and neutrophil function following eel, reflect a transient, post-exercise suppression of cellular immunity. despite a partial dampening thereof by the anti-inflammatory actions of il-10, il-1ra and il-6, the evidence supporting a pro-inflammatory response to prolonged exercise and overtraining is unequivocal. at present, the data appear to support the theory that symptoms of ‘infection’ experienced by athletes are the manifestation of a significant pro-inflammatory response, combined with a modest, transient suppression of cellular immune functions which may be clinically insignificant. correspondence: e m peters department of physiology nelson r mandela school of medicine private bag 7 congella 4013 south africa tel: 031-260 4237 fax: 031-260 4455 e-mail: futree@nu.ac.za nk activity iga levels lymphocyte counts severe exercise post exercise immunodepression open window fig. 1. the exercise-induced open-window period (adapted from pedersen and ullum.52) 4 sports medicine vol 16 no.1 2004 tively new field of exercise immunology. as noakes, however, so appropriately concludes in his most recent version of the lore of running,47 ‘it is my impression that a considerable amount of research has been done in this field without any practical advances being made’. in 1994 nieman45 postulated that the relationship between exercise-load and ‘infection risk’ could be modelled in the form of a j-shaped curve, suggesting that although the risk of upper respiratory tract infection (urti) may decrease below that of a sedentary individual undergoing moderate exercise training, risk may rise above average during periods of excessive amounts of high-intensity exercise.45 in 1999 he introduced a further dimension to this graphic model; while ‘infection risk’ increased, ‘immunsurveillance’ decreased and vice versa (fig. 2).39 temporary modulations of innate and adapted immune function have been alleged to be the basis for the relationship between the level of physical activity and susceptibility to infection. while limited evidence of enhancement of immune function has been found following moderate exercise exposure,4,25,30,38 it has been shown that excessive prolonged exercise transiently suppresses markers of both cellular and humoral adaptive immunity15,26,28,35,42,70 and to a lesser degree, some aspects of non-specific immunity including neutrophil respiratory burst8,61-63,66,78 and natural killer (nk) cell activity.21,26,27 yet a consistent correlation between this temporary ‘suppression’ of markers of immune function and incidence of urti infection symptoms following excessive exercise load (eel) has not been found. the closest link that has been shown has been in the work of exercise immunologists of the australian institute of sport and university of queensland who were able to show that a decrease in salivary immunoglobulin (iga) concentration is associated with a corresponding enhanced infection incidence in elite, overtrained swimmers and kayakers.12,16-19,65 however, the recent debate regarding the validity of the practise of expressing salivary iga as a function of salivary total protein or albumin concentrations when these have different origins,3 makes explanation of the results elusive and leaves exercise immunologists with little alternative but to acknowledge that the transient suppression of markers of immune function which have been reported in the last two decades may not be of clinical significance. in re-examining possible factors which could account for the higher incidence of what have primarily been self-reported symptoms of urti, a number of interesting new perspectives and hypotheses have arisen. broadly, these can be divided into three general categories: those supporting allergy, inflammation or infection. let us examine each of these in turn. a case in favour of allergic origins? an enlightening dimension of recent immunological studies on exercising individuals has involved the analysis of the post-event cytokine milieu (table i). it is well accepted that the cd4 lymphocyte subsets, thelper-1 (th1) and t-helper-2 (th2), impact differentially on cellular and humoral lymphocyte function.14,67,77 as direct measurement of the cd 26 (th1) and 30 (th2) cell surface molecules is not possible due to their instability, a comprehensive picture of the cytokine milieu created by cells of the immune system is the best evidence which we presently have of th1:th2 balance following eel. whereas the type 1 cytokines, interleukin (il)-2, interferon gamma (ifn γ), tumour necrosis factor (tnf)α and il-12 activate the development and activation of th1 cells which upon recognition of antigens, stimulate cell-mediated immunity increasing cd8 and nk cell cytotoxic activity as well as activating macrophages and neutrophils to kill the bacteria they harbour, th2 upregulation has been shown to augment b-cell antibody production via the release of the type 2 cytokines, il-4, il-5, il-6, il-10 and il-13. suzuki et al.77 and smith72 have recently proposed an hypothesis which suggests an exercise-induced shift in cytokine balance from type -1 to type-2 cytokines with an upregulation of th2 cells (as confirmed by substantially elevated post-exercise concentrations of il-6 and il-10) and a relative downregulation of th1 helper cells, as expressed in elevated circulating cortisol and prostaglandin e2 concentrations73 and unchanged/slightly decreased type 1 cytokine concentrations following eel (table i). this exercise-induced ‘tipping’ of the th1: th2 balance (fig. 3) differs significantly from the cytokine milieu present in auto-immune disorders which present with elevated il-2, ifnγ and il-12 concentrations. the high prevalence of exercise-induced asthma, anaphaxis and systemic histamine release recently reported by helenius et al.,13 mucci et al.,23 shadick et al.,69 and sue-chu et al.,76 has encouraged exercise immunologists to look more deeply into this shift in th1:th2 balance following exercise which appears to support upregulation of humoral immunity and allergic responses with simultaneous downregulation of cell-mediated immunity. while il-10 plays an important role in upregulating th2 cells and inhibiting th1 lymphocyte development, 72 it is well accepted that il-4 is the dominant cytokine in the upregulation of th2 lymphocytes promoting their differentiation and inducing further type 2 cytokine production.67 this cytokine is therefore the ‘key player’ in supporting humoral immunity and possible allergen-derived activation of eosinophils/mast cells and ige production. there is, however, presently little fig. 2. the paradoxical relationship between workload, infection risk and immunosurveillance in athletes (adapted from nieman et al. 38) sports medicine vol 16 no.1 2004 5 evidence of exercise-induced elevation of circulating il-4 concentrations and preferential post-exercise synthesis of ige following exercise.32,75 although il-6 (which rises dramatically during prolonged exercise24,29,31), is thought to stimulate the production of il-4, steensberg et al.75 were not able to show evidence of its production in cd4+ cells. additional work on the kinetics of il-4 is therefore required before the th1 -th2 hypothesis can be substantiated. the significant post-exercise elevations of il-10, a potent suppressor of cellmediated immunity and anti-inflammatory cytokine, as well as the multifunctional il-6 and chemotactic il-8 (table i), further complicate the argument in favour of a cytokine balance which is exclusively associated with allergic-type reactions. the case for and against infectious origins despite the above-described evidence of the presence of a type 2 post-exercise cytokine milieu which points to modest, transient downregulation of the cellular components of specific and innate immunity, it would appear that, at this stage, there is little support for a truly infectious origin of the urti symptoms experienced by athletes following an eel. as findings of transient suppression of lymphocyte count and proliferation,34,41 nk-cell counts and cytolytic activity,21,26 salivary iga concentrations11,12,20 and phagocytic oxidative burst activity8,37 have not been shown to be paralleled by increased incidence of ‘infection’, the clinical significance of these findings is in question. table i. the cytokine milieu in the blood following prolonged exercise in excess of 2 hours exercise-induced changes cytokine primary cell source primary functions in peripheral blood tumour necrosis factor activated macrophages, nk, primary mediator of sirs; stimulation changes inconsistent, but (tnf)∝ t-cells, b-cells of release of acute phase proteins, concentrations remain within lymphocyte proliferation & killing clinically normal range 32,48,56, 57 interferon (ifn) ∝ & ß epithelia, fibroblasts, macrophages antiviral; activation of nk cells no change interferon (ifn)γ activated th1 cells, nk cells antiviral; activation of macrophages, 50% ↓ (steensberg et al.75*) neutrophils, nk cells, inhibition of th2 cells no change undectectable (nieman et al.,32 gannon et al.9) interleukin-1 ß (il-1 ß) macrophages, monocytes mediator of sirs; activation of 1.5 2-fold↑ (nieman et al.,40 phagocytosis, b-cell proliferation; ig ostrowski et al.48,50) production interleukin-2 (il-2) activated th1 cells, nk cells modulator of th2 cell proliferation & 32% ↓ suzuki et al.77) function; igg expression 50 % ( (steensberg et al. 75*) interleukin-4 (il-4) th2 cells, mast cells, basophils, downregulation of tnfα and il1ß; no change (nieman et al.32 eosinophils induction of il-6, il-10, il1ra malm22, steensberg et al.75*) synthesis; b-cell proliferation and class delayed onset secretion after 2 switching to ige expression. hrs (susuki et al.79) interleukin-5 (il-5) th2 cells, mast cells, eosinophils eosinophil & b-cell growth and differentiation. no consistent change (malm 22) interleukin-6 (il-6) activated th2 cells, apcs, active multi-functional; b-cell proliferation 30-fold ↑ (steensberg et al,75*) skeletal muscle fibres and ig & acute phase protein synthesis; 30-fold ↑ (peters et al.57) inhibition of synthesis of tnfα and il100-fold ↑ (starkie et al.74) 1ß; induction of cortisol, il-10 & il1ra synthesis interleukin-8 (il-8) macrophages chemotaxis, superoxide release, 6-fold↑ (peters et al.55) granule release 6.7-fold ↑(ostrowski et al.49) interleukin-10 (il-10) activated th2, cd8 and b inhibition of synthesis of tnfß, il1ß, 60-fold ↑ (peters et al.56) lymphocytes, macrophages ifnγ, il-6, il-8 by th1 cells, nk cells 40-fold↑ (nieman et al. 32) & apcs; promotion of b-cell proliferation & antibody responses, mast cell growth interleukin 12 (il-12) monocytes activation of th1 cells undetectable (nieman et al, 32 nk stimulating factor suzuki et al.79, gannon et al.9) ifn γ production increased† (akimoto et al.1) interleukin 13 (il-13) th2 cells b-cell growth & differentiation, inhibition of no exercise-related data available pro-inflammatory cytokine production interleukin 15 (il-15) skeletal muscle cells, t and b-cell proliferation, increase of no change (ostrowski et al.48). endothelium, monocytes. myosin heavy chain expression in skeletal muscle. interleukin-1ra (il-1ra) macrophages, th2 cells inhibition of pro-inflammatory action of 20 fold↑ (peters et al.56) il-1 by blocking il-1 α & ß receptors; 40 fold↑ (toft et al.80) no agonist activity 214 fold↑(suzuki et al.79) * intracellular concentrations (cd4 + cells). †short-term maximal exercise. apc = antigen presenting cell; th1 = t-helper-1; th2 = t-helper-2; ig = immunoglobulin; sirs = systemic inflammatory response syndrome. (ganong,10 janeway and travers,14 roitt et al.,67 smith 72) although the open-window hypothesis of pedersen and ullum52 and pedersen et al.54 describes a period of increased susceptibility to infection which may last from 3 to 72 hours post-exercise, most exercise-induced haematological perturbations have returned to baseline values within 16 hours post-exercise.60 as shepard and shek71 point out, ‘it is difficult to reconcile a 2-to 3-hour reduction of nk cell activity with the reported 2-to 6fold increase in the incidence of urtis in the weeks following participation in a marathon or ultramarathon run’. furthermore, antibody responses following vaccination have not been shown to be influenced by exercise training,5 while negative bacterial throat swabs obtained by schwellnus et al. following the two-oceans 56 km ultramarathon also appear to rule out the possibility of enhanced incidence of post-race infection symptoms being of infectious origin (m schwellnus — personal communication). as false-negative bacterial throat swabs are, however, a common occurrence in clinical practice, we cannot, at this stage, consider these data as conclusive. the evidence in support of a decrease in delayed type hypersensitivity (dth) reactions, the t-cell-dependent activation of macrophages and inflammation in response to a previously encountered antigen, is also presently conflictling; while bruunsgaard et al.5 found decreased dth after a one-half ironman race, jansen et al. (personal communication), failed to show any change following 8 weeks of training in excess of 110 km/week. the case in favour of inflammatory origins the evidence in favour of an inflammatory response both to epithelial tissue damage in the upper respiratory tract and muscle fibre damage in the contracting skeletal muscle fibres, as manifested in systemic markers of an inflammatory response, is, however, strong. during prolonged endurance exercise increased ventilatory rates and volumes, with actual damage to sensitive mucous membranes in the respiratory tract, and an inflammatory response at the sites of muscle cell damage have been linked to the development of an acute phase reaction.80 evidence of systemic manifestation of pro and antiinflammatory response to exercise-induced microtrauma (whether this be in the contracting muscle itself or in the respiratory tract membranes exposed to excessive mouth 6 sports medicine vol 16 no.1 2004 il-4 il-5 il-10 il-6 il-8 il-13 tnf α eel t1h cells il-12 il-2 ifn γ tg β tnf β th2 cells cell mediated immunity: macrophages, pmns, nk, tc cells pro-inflammatory response: phagocyte mobilisation & activation eel humoral immuntity: allergic response fig. 3. the exercise-induced disturbance of cytokine equilibrium: a downregulation of type 1 and upregulation of type 2 cytokines. promotion; inhibition; eel : excessive exercise load; th1: t-helper-1; th2: t-helper-2; pmn : polymorphonuclear neutrophils; tc : cytotoxic t-cells; nk cells: natural killer cells. breathing) has been confirmed by numerous studies focusing on exercise-induced cytokine changes. in addition to the early studies which consistently confirm the presence of increased prostaglandin e2 concentrations, 53,73 the endocrine,43,44,64,72 cytokine,36,48-51 acute phase protein,6,7,81 and enzymatic66 milieu in the circulation favours an inflammatory response (fig. 4). in three consecutive studies following the 90 km ultramarathon, we have confirmed systemic evidence of a proinflammatory response.55-57 not only are markers of an acute phase reaction, crp and amyloid a consistently elevated, peaking 24 hours after a race and reaching concentrations in excess of those reported following myocardial infarctions,55,57 but also a cascade of pro-inflammatory and chemotactic cytokines40,56 and systemic markers of phagocyte activation including myeloperoxidase, elastase and neutrophil/ monocyte adhesion factors.55,61,66 our most recent research findings confirm elevated concentrations of neutrophils and monocytes expressing cd11 a and b integrins which control the movement of leukocytes towards areas of inflammation following 2.5 hours of treadmill running at 70% vo2max. (peters et al., unpublished data). the substantial elevation of circulating anti-inflammatory mediators, il-10, il-1ra and il-6 (fig. 5) do, however, point towards a partial dampening of this pro-inflammatory response. despite this endogenous attempt to counter the exercise-induced inflammation, systemic markers of an acute phase reaction peak at 24 hours post-event. in 1997 schwellnus et al.68 reported that administration of the local antimicrobial and anti-inflammatory agent, fusafungine, significantly reduced post-race urtis in 48 participants during the 9 days following the 1996 two oceans 56 km ultramarathon. however as this nasobuccopharangeal spray has both anti-inflammatory and antiinfective properties, this intervention study on its own does not provide conclusive evidence that the increased incidence of infection following eel is solely attributable to an inflammatory response. perhaps we should also not ignore the early finding of pedersen et al.53 that administration of the non-steroidal antiinflammatory agent, indometacin, which inhibits prostaglandin e2 release and the inflammatory response, reduces post-exercise suppression of nk cell activity and restores post-exercise neurophil chemiluminescence in peripheral blood. as the authors concluded, these findings strongly indicate that prostaglandins released from monocytes and neutrophils, are involved in the downregulation of nk cells, again pointing towards systemic manifestation of an inflammatory response. an answer? at this stage, there is not enough evidence in favour of an exclusive contribution of allergic, inflammatory or infective origins to the incidence of post-event urti symptoms. sports medicine vol 16 no.1 2004 7 fig. 4. mean (± sem) circulating acute phase protein (crp and amyloid a), elastase and interleukin-8 concentrations before and after a 90 km ultramarathon, which support an upregulation of inflammatory responses (data from peters et al. 55) *p > 0.05 (n = 29). 60 50 40 30 20 10 0 time s e ru m c p r ( m g /l) pre 0 hrs 24 hrs 48 hrs post post post 250 200 150 100 50 0 time s e ru m a m yl o id a ( m g /l) pre 0 hrs 24 hrs 48 hrs post post post 200 180 160 140 120 100 80 60 40 20 0 time p la sm a e la st a se ( µ g /l) pre 0 hrs 24 hrs 48 hrs post post post 30 25 20 15 10 5 0 time p la sm a i n te rl e u ki n -8 ( p g /m l) pre 0 hrs 24 hrs 48 hrs post post post 8 sports medicine vol 16 no.1 2004 in terms of the th1: th2 balance hypothesis which favours an allergic response, the evidence in favour of exerciseinduced production of il-4 requires further elucidation. the exercise-induced ‘switching’ of b-cells to a preferential production of ige and significant upregulation of igg1 production in response to mast cell activation also requires further confirmation. in terms of the inflammation and infection-based hypotheses, supportive data are undoubtedly strong. while transiently and modestly suppressed cellular components of immunity including cytotoxic t lymphocytes, nk cells and in the case of eel, neutrophil function are supported by a relative downregulation of type 1 cytokines, the post-exercise cytokine, acute phase protein and adhesion molecule milieu strongly supports an upregulation of inflammatory responses. shephard and shek71 have eloquently referred to the ‘active enmeshment’ of the immune system in the muscle tissue repair and inflammation process. it is indeed possible that a significant upregulation of inflammatory response is accompanied by a simultaneous modest, but clinically insignificant, transient downregulation of the cellular cytotoxic activity of the t and nk cells; that the observed immunological changes during and after physical exercise which have been previously interpreted as ‘depressed immune function,’ reflect a proactive inflammatory response which is a necessity for optimal adaptation following the increased physical demand of eel and should therefore not be viewed in a negative light. a paradox, 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respiratory tract infections. int j sports med 1997; 18: s69. 60. peters, em, robson pj, kleinveldt n, naiker v. haematological recovery following ultramarathon running: the effect of training status and taper. j sports med phys fit (in press). 61. peters-futre em. exercise, vitamin c and phagocyte function. the missing link. exerc immunol rev 1997; 3: 32-52. 62. pyne db, baker ms, fricker pa, mcdonald wa, telford rd, weideman mj. effects of an intensive 12 wk training program by elite swimmers on neutrophil oxidative activity. med sci sports exerc 1995; 27: 536-42. 63. pyne db, baker ms, telford rd, weideman mj. neutrophil oxidative activity is differentially effected by moderate and intense interval exercise. med sci sports exerc 1993; 25: s102. 64. pyne db, gleeson m. effects of intensive exercise training on immunity in athletes. int j sports med 1998; 19: s183. 65. pyne db, mcdonald wa, gleeson m, flanagan a, clancy rl, fricker pa. mucosal immunity, respiratory illness, and competitive performance in elite swimmers. med sci sports exerc 2000; 33: 348-53. 66. robson pj, blannin ak, walsh np, castell lm, gleeson m. effects of exercise intensity, duration and recovery on in vitro neutrophil function in male athletes. int j sports med 1999; 20: 128-35. 67. roitt i, brosstoff j, male d. immunology. 5th ed. st louis: mosby, 2000. 68. schwellnus m, kiesig m, derman w, noakes td. fusafungine reduces symptoms of upper respiratory tract in runners after a 56 km race. med sci sports exerc 1997; 29: s296. 69. shadick na, liang mh, partridge aj, et al. the natural history of exercise-induced anaphalaxis: survey results from a 10-year follow-up study. j allergy clin immunol 1999; 104: 123-7. 70. shek pn, sabiston bh, burguet a, radomski mw. strenuous exercise and immunological changes. a multiple-time point analysis of leukocyte subsets, cd4/cd8 ratio, immunoglobulin production and nk response. int j sports med 1995; 16: 466-74. 71. shephard rj, shek pn. impact of physical activity and sport on the immune system. rev environ health 1996; 11: 133. 72. smith l. overtraining, excessive exercise and altered immunity. is this a t helper-1 versus t helper-2 lymphocyte response? sports med 2003; 33: 347-64. 73. smith ll, wells jm, houmard ja. increases in prostaglandin e2 after eccentric exercise: a preliminary report. horm metab res 1993; 25: 4512. 74. starkie rl, angus dj, rolland m, hargreaves m, febbraio ma. effect of prolonged submaximal exercise and carbohydrate ingestion on monocyte intracellular cytokine production in humans. j physiol 2000; 528: 647-55. 75. steensberg a, dyhr, toft a, bruunsgaard h. strenuous exercise decreases the percentage of type 1 cells in the circulation. j appl physiol 2001; 91: 1708-12. 76. sue-chu m, larson t, moen t, rennard si, bjermer l. bronchocscopy and bronchoalveolar lavage findings in cross country skiers with and without ‘ski’ asthma. eur respir j 1999; 13: 626-32. 77. suzuki k, nakaji s, yamada m, totsuka m, sato k, sugawara k. systemic inflammatory response to exhaustive exercise. exerc immunol rev 2003; 8: 6-48. 78. suzuki k, nakaji s, yamada m, et al. impact of a competitive marathon race on systemic cytokine and neutrophil responses. med sci sports exerc (in press). 79. suzuki k, yamada m, totsuka m, sato k, sugawara k. circulating cytokines and hormones with immunosuppressive but neutrophil-priming potentials rise after endurance exercise in humans. eur j appl physiol 2000. 814: 281-7. 80. toft ad, thorn m, ostrowski k, et al. npolunsaturated fatty acids do not affect cytokine response to strenuous exercise. j appl physiol 2000; 89: 2401-6. 81. weight lm, alexander d, jacobs p. strenuous exercise: analogous to the acute phase response? clin sci 1991; 81: 677-83. sports medicine vol 16 no.1 2004 9 46 sajsm vol 18 no.2 2006 introduction asthma and airway hyperresponsiveness (ahr) are more prevalent in elite athletes compared with sub-elite athletes and the general population. 18,35,46 recent observations have suggested that high-intensity exercise and training might contribute to the development of asthma or ahr in athletes previously unaffected by these airway disorders. 7,8,20,24 the mechanisms explaining the increased prevalence of asthma and ahr remain to be determined. 5 however, research has suggested that exposure to specific local airway conditions and/or events during training and/or competition may initiate an airway inflammatory response. 23 airway inflammation may influence the respiratory system through altering airway function 5 , and possibly inducing airway remodelling, similar to that which occurs in asthma. 8 this article discusses the recent research regarding asthma, ahr and airway inflammatory responses in athletes. firstly, an overview of the prevalence of airway symptoms in athletes is provided. secondly, research examining local airway conditions, events and inflammatory responses is discussed. thirdly, research examining the possible remodelling of the airways in athletes is reviewed and finally, recommendations for future research in this area are provided. prevalence of asthma and ahr in sport in the 1976 and 1980 olympic games, 9.7% and 8.5% of the australian olympic athletes had asthma, respectively. 12 in 1984, 26 (4.3%) of the 597 us olympic team athletes had asthma, 41 (6.9%) had exercise-induced bronchospasm (eib), while 42 (7%) had a history of exercise-induced bronchial symptoms. 16 weiler et al. 44 reported that 107 (15.3%) of the 699 us olympic team athletes in the 1996 summer olympic games had asthma. in 1998, the same authors observed a prevalence of 21.9% in 196 winter game olympic athletes. 44 from these few studies it seems that the prevalence of atopy-related symptoms is rising in elite athletes. the type of training (i.e. endurance, or speed and power) seems to influence the airway symptoms (asthma or ahr) in elite athletes. 17 the prevalence of atopic symptoms is high in endurance sports such as long-distance running (15.5 23.9%). 17 it is especially high in cold environment sports such as cross-country skiing (14.4 54.8%), 17 as well as in review article airway inflammatory and atopy-related responses in athletes a j mckune (dtech) l l smith (phd) department of sport and physical rehabilitation sciences, faculty of health sciences, tshwane university of technology, pretoria abstract the prevalence of asthma and airway hyperresponsiveness (ahr) in highly trained endurance athletes is rising. the type of training (i.e. endurance, or speed and power) seems to influence the airway symptoms. high-intensity exercise and training might contribute to the development of asthma or ahr in athletes previously unaffected by these airway disorders. repeated hyperventilation of unconditioned air, as well as air containing irritants and/or allergens has been suggested to cause thermal, mechanical, or osmotic airway trauma resulting in damage to the airway epithelium. subsequent airway inflammatory responses may be responsible for the development of atopy-related symptoms in endurance athletes such as those observed in asthma and ahr. eosinophils and neutrophils are the inflammatory cells that have been frequently observed to be elevated in the airways of endurance athletes. the trafficking of these cells to the airways may possibly be regulated by th2 cytokines that are expressed in the airways in response to epithelial cell damage. in addition, these airway inflammatory responses may lead to airway remodelling similar to that which occurs in asthma. the effect of the exercise challenge itself may initiate airway atopy-related and inflammatory responses in endurance athletes. while the literature seems to support the role of local airway conditions and/or events in inducing atopy-related symptoms in athletes, it is proposed that alterations in the hormonal and/or cytokine milieu with intense competition and/or training may also play a role. correspondence: a j mckune department of sport and physical rehabilitation sciences tshwane university of technology private bag x680 pretoria 0001 tel: 012-382 4442 fax: 012-382 5801 e-mail: mckuneaj@tut.ac.za pg46-51.indd 46 6/28/06 1:47:43 pm sajsm vol 18 no.2 2006 47 swimmers training indoors (13.4 44%). 17 for speed and power sports, including various athletes such as sprinters, football players and basketball players, the prevalence of asthma is slightly lower and usually ranges from 8% to 21%. 17,23 effect of local airway conditions and events on airway atopy-related symptoms and inflammatory responses dry, cold air exercise hyperventilation with dry, cold air plays an important role in the development of airway symptoms in athletes. 23 it causes transient dehydration of the bronchial mucosa due to the low water content of the air, leading to a hyperosmolarity of the mucosal fluid of the airway surface lining, which may damage bronchial epithelial cells. 1,14 the hyperosmolarity of the mucosal fluid alters the osmotic gradient throughout the mucosa and sub-mucosa, resulting in the activation and degranulation of mast cells in the sub-mucosa. degranulation of these mast cells results in the release of pro-inflammatory mediators and the activation of cholinergic receptors. 23 this response causes airway smooth-muscle contraction and oedema which together reduce airway function, resulting in atopy-related airway symptoms. 1,4 it has recently been proposed that eosinophils in the airways become activated via a similar mechanism to that of the mast cells. 9 research has indicated that the increased respiratory water loss during prolonged endurance exercise dehydrates the bronchial epithelium. the increased osmolality or osmotic challenge then indirectly triggers the release of eosinophil cationic protein (ecp) from eosinophils, 9 resulting in further epithelial cell damage, inflammatory responses and consequently airway atopy-related symptoms. 9 the inflammatory mediators that have been suggested to be implicated during these airway inflammatory responses include histamine, prostaglandins, leukotrienes, and chemotactic factors (chemokines), including il-8 for neutrophils 5 and eotaxin for eosinophils. 33 in contrast to the studies mentioned above, sue-chu et al., 39 found that there were no significant differences in neutrophil or eosinophil counts/activation, but that other inflammatory markers significantly differed between athletes and controls. examining the effect of hyperventilation of cold, dry air, these authors assessed the degree of macroscopic inflammation, the distribution of inflammatory cells, lymphocyte subtypes and markers of inflammatory cell activation in the airways of 30 adolescent cross-country skiers and 10 non-asthmatic, non-atopic controls. 39 the airways of these subjects were investigated using bronchoscopy, and inflammatory status was determined through analysing levels in bronchoalveolar lavage fluid (balf). nine (30%) of the skiers were atopic without allergy symptoms. compared with controls there was a 3-fold increase in airway inflammation in the skiers. they also had greater total cell, percentage lymphocyte and mast cell counts compared with the controls. neutrophil and eosinophil counts were not significantly different and ecp was not detected. tumour necrosis factor (tnf)-α and myeloperoxidase were detected in 12 (40%) and 6 (20%) skiers, respectively. the authors concluded that cross-country skiers have a minor to moderate degree of macroscopic inflammation in the proximal airways compared with normal controls. 39 recently, it was reported that exposure to cold air during exercise may up-regulate specific airway cytokine expression that may be responsible for inflammation and atopy-related conditions in the airways of athletes. 7 using an animal model (exercising horses) and a random crossover design, balf was obtained after 15 minutes of submaximal exercise while breathing room temperature or subfreezing air. balf total and differential nucleated cell counts and relative cytokine mrna expression in balf nucleated cells were determined. there were no differences in total or differential cell concentrations between the room temperature and cold air conditions. however, th2 cytokines il-4, il-5, and il-10 were significantly upregulated after cold air exercise 12-, 9-, and 10-fold respectively compared with warm air exercise. in addition, other cytokines, il-2 and il-6, were upregulated to a lesser extent (6and 3-fold respectively) or not at all (il-1, il-8, ifn-α, and tnf-α). the authors argued that exercising while breathing cold dry air induces an overall cytokine pattern in the airways that is predominantly a th2 profile. 7 th2 cytokines, in support of the underlying theme of this review, are a characteristic of the systemic immune profile found in allergies and asthma where they regulate the production of ige antibodies as well as the infiltration of inflammatory cells such as neutrophils and eosinophils. 43 allergens runners, and cyclists are exposed to many pollen allergens in spring and summer. 42 when the ventilation level exceeds about 30 l/min there is a shift from nose breathing to combined mouth and nasal breathing. 2 this shift results in a greater deposition of airborne allergens and other inhaled particles in the lower airways. 19 research has demonstrated that symptoms of asthma may develop in athletes who are repeatedly and strongly exposed to pollen allergens. 32 this author suggested that an allergen overload in the airways could lead to an inflammatory process through an ige dependent mechanism. in other words, the high number of allergens within the airways could increase the possibility that ige attached to mast cells become cross-linked. this in turn would lead to an acute inflammatory response through mast cell degranulation and the release of airway pro-inflammatory mediators. 23 pollutants the quality of the air inhaled by athletes during training or even at rest may contribute to the development of ahr. a relationship has been shown between pollutants such as, pg46-51.indd 47 6/28/06 1:47:43 pm 48 sajsm vol 18 no.2 2006 ozone (o3), sulphur dioxide (so2), nitrogen dioxide (no2), exercise and the development of atopy-related respiratory symptoms. 23 studies have demonstrated that the combination of exercise and exposure to pollutants can cause a significant increase in bronchoconstriction and a reduction in ventilatory flow when compared with pollution exposure at rest. 13,27 swimmers, chlorine and ahr research has found an abnormally high prevalence of ahr among elite swimmers. 31 studies have shown that swimmers are chronically exposed to chemical compounds used as water disinfectants. 10 these disinfectants include chlorine and its derivatives, chloramines and chloroform, which irritate the airways, causing inflammation and oedema of mucous membranes. 31 research has shown that during a 2-hour training period, a swimmer may be exposed to an amount of chlorine that exceeds the us recommendation for a worker with 8-hour exposure. 10 during training and competition, highly trained swimmers inhale large amounts of air that floats just above the water surface, and they may possibly micro-aspirate contaminated water into the trachea and bronchi. 16 repeated exposure to chlorine gas has been shown to cause asthma symptoms, airflow obstruction, and increased bronchial responsiveness. 6 in these cases, the histological analysis of the bronchial mucosa has shown a thickened basement membrane, and eosinophilic inflammation. 6 a long-term effect of swimming training on airway inflammation was reported by helenius et al. 20 these authors investigated respiratory symptoms, increased bronchial responsiveness, and signs of airway inflammation in 29 elite swimmers and 19 healthy controls. the subjects answered a questionnaire and were interviewed for respiratory symptoms. lung volumes were measured and bronchial responsiveness was assessed by a histamine challenge test. induced sputum was also collected. fourteen (48%) of the swimmers and 3 (16%) of the control subjects showed significantly increased bronchial responsiveness. the sputum cell differential counts of eosinophils and neutrophils of swimmers were significantly higher than those of controls. eosinophilia (sputum differential eosinophil count of > 4%) was observed in 6 (21%) of the swimmers and in none of the controls. symptomatic swimmers had significantly more sputum eosinophils than did those who were symptom-free. the concentrations of sputum eosinophil peroxidase (epo) and human neutrophil lipocalin (hnl) were significantly higher in swimmers than in control subjects. the authors concluded that long-term and repeated exposure to chlorine compounds in swimming pools during training and competition may contribute to the increased occurrence of bronchial hyperresponsiveness and airway inflammation in swimmers. 20 summary of research examining airway inflammation in athletes surprisingly, there are few studies that have addressed the issue of exercise-induced airway inflammatory responses in athletes. in addition to the studies already discussed, a summary of the majority of research available is provided in table i. overall, the results indicate that an increase in polymorphonuclear neutrophil (pmn) cells is found in most studies irrespective of the sample type or sport activity, while elevated eosinophil and lymphocyte counts are found mainly in swimmers and skiers. it has been suggested that the elevation in pmns may be a direct consequence of the endurance exercise, while the elevation in the other cell types may depend on exposure to environmental factors such as chlorine or cold, dry air. 4 however, this statement is highly speculative and requires additional research. importantly, the only study examining an underlying mechanism which may explain exercise-induced airway inflammatory responses and the development of atopy-related symptoms has been performed using an animal model. 8 the results of this study have important implications for understanding the high prevalence of atopy-related airway symptoms in athletes. however, further research on humans is required to verify the findings. limited airway inflammatory responses in athletes in contrast to the previous discussion regarding airway inflammatory responses inducing atopy-related symptoms in athletes, there is an argument that the airway inflammatory responses are not maladaptive. research has suggested that similar to systemic compartments, inflammation in the airways is tightly regulated. recently, it has been argued that the concept of limited systemic inflammation in athletes may also be applicable to the airways. 4 although inflammatory cells are recruited to the airways, it has been shown that they do not always become activated. 3,25 as an example, in swimmers there was significant neutrophil infiltration into the airways, but with no evidence of inflammatory cell activation at rest or after exercise. specifically, neutrophil elastase concentration in sputum was low at all times. 28 preliminary data also suggested that an increase in airway inflammatory cells is not associated with enhanced bronchial responsiveness or functional impairment in nonasthmatic athletes. 4 interestingly, research has shown that frequent episodes of exercise hyperventilation may even reduce the susceptibility to bronchoconstriction in welltrained individuals. specifically, well-trained runners showed blunted responses to metacholine compared with sedentary controls. 4 therefore, there may be an inhibitory pathway that prevents or reduces airway inflammatory cell activation and inflammation; however, this has not been identified and further research is required. 4 similarly, the questions regarding whether exercise affects the airway and systemic compartments in the same manner, and the possibility that pg46-51.indd 48 6/28/06 1:47:44 pm sajsm vol 18 no.2 2006 49 training may also cause positive adaptations at the airway level, have not been answered. 4 airway remodelling airway remodelling has been shown to occur in atopic disease such as asthma. the process is initiated through chronic airway inflammation and is associated with a continual or abnormal healing process resulting in airway structural alterations. 23 this remodelling process is characterised by various changes such as hypertrophy and hyperplasia of airway smooth muscle, increased numbers of mucous glands, thickening of the reticular basement membrane from collagen deposition, blood vessel proliferation, and alterations of the extracellular matrix. 26 these, in turn, lead to airway wall thickening and a permanent reduction in airway calibre with a detrimental effect on respiration. 23 airway remodelling in athletes there is little information available that links exercise hyperventilation with the induction of structural and/or physiological changes in the airways. 23 some preliminary evidence of airway remodelling has been demonstrated in bronchial biopsies from cross-country skiers. 21 karjalainen et al. 21 measured mucosal inflammatory cell infiltration and tenascin expression (a marker of tissue injury) in the sub-epithelial basement membrane in endobronchial biopsy specimens of the proximal airways. the subject populations included 40 elite, competitive skiers without a diagnosis of asthma, 12 subjects (non-athletes) with mild asthma, and 12 healthy controls (non-athletes). skiers had significantly higher lymphocyte (+43-fold), macrophage (+26fold) and eosinophil (+2-fold) counts compared with healthy controls. patients with mild asthma also had significantly table i. studies on airway inflammatory responses to exercise author, year (ref) athletes tested methods main results cross-country skiers sue-chu et al. 1999 39 cross-country skiers balf ↑ total cell, lymphocyte, and mast cell counts; markers of inflammatory cell activation not ↑ karjalainen et al. 2000 21 cross-country skiers bb compared with controls, ↑ t-lymphocytes (43-fold), macrophages (26-fold), eosinophils (2-fold), pmn (2-fold) in bronchial mucosa. no relationship between airway cells and bhr, symptoms or atopy sue-chu et al. 2000 38 cross-country skiers balf, bb no change in airway inflammation after budesonide treatment after inhaled steroid (800 µg/day, over 20 weeks), variable effect on symptoms treatment swimmers helenius et al. 1998 18 elite swimmers induced sputum ↑ pmn and eosinophil differential counts compared with controls; ↑ inflammatory markers; eosinophils = 4% in 21% of swimmers helenius et al. 2002 15 elite swimmers 5-year follow-up induced sputum eosinophil differential counts ↑ over time in athletes continuing competitions, decreased in athletes who quit morici et al. 2001 28 swimmers training outdoors induced sputum baseline: ↑ pmn differential counts (swimmers 44 ± 22%; sedentary controls: 10 ± 6%), no ↑ in eosinophils; 5-km swimming in outdoor pool: no change; 5-km swimming in the sea (hypertonic environment): slight ↑ in eosinophils boulet et al. 2005 5 swimmers training indoors induced sputum baseline: no ↑ in airway inflammation in high-level swimmers; shortterm high-intensity training (1 h) associated with an ↑ in airway neutrophils in hyperresponsive swimmers runners muns 1993 29 half-marathon runners nasal lavage post-half-marathon: immediately after ↑ pmn (3-fold); 24 h after remained elevated (1.6-fold) compared with pre-race. ↓ in % phagocytosing pmns and function pre-race, immediately after and after 24 h muns et al. 1996 30 marathon runners nasal lavage post-marathon: immediately after ↑ pmn (2.7-fold); remained elevated up to 3 days after. ↑ neutrophil chemotactic activity (2.5-fold) immediately after the race bonsignore et al. 2001 3 marathon runners induced sputum baseline: ↑ pmn differential counts (79 ± 9%); post-marathon: further ↑ pmn (91 ± 4% of total cells) wetter et al. 2002 45 endurance athletes with ahr induced sputum baseline: pmn differential counts: 37% (range 13 49, no control samples); post-exercise: unchanged after placebo or anti-inflammatory drugs boulet et al. 2005 5 marathon runners induced sputum baseline: no ↑ in airway inflammation in high-level runners; short-term high-intensity training (1 h) associated with no ↑ in airway inflammation davis et al. 2005 7 horses balf post-15 minutes submaximal exercise. ↑ th2 cytokine (il-4, il-5, il-10) expression after cold air exercise compared with warm-air exercise balf = bronchoalveolar lavage fluid; bb bronchial biopsy; pmn = polymorphonuclear neutrophil; bhr = bronchial hyper-reactivity. pg46-51.indd 49 6/28/06 1:47:44 pm 50 sajsm vol 18 no.2 2006 higher lymphocyte (+70-fold), macrophage (+63-fold) and eosinophil (+8-fold) than the controls. in the skiers, neutrophil counts were more than 2-fold greater than in asthmatic subjects. tenascin expression was increased in skiers and asthmatic subjects compared with controls. however, the bronchial biopsy findings did not correlate with ahr, atopy or symptoms of asthma. 21 these authors concluded that prolonged repeated exposure of the airways to inadequately conditioned air may induce inflammation and remodelling in competitive skiers. 21 it is possible that airway remodelling without airway symptoms may represent a form of adaptation to exercise hyperventilation within the airways. in other words, this may be 'healthy' remodelling rather than maladaptive. further research is required to test this hypothesis. however, a recent study, using a canine model, demonstrated that repeated hyperventilation of cold air during exercise may in fact cause airway inflammation and remodelling, leading to asthma-like symptoms. 8 daily, repeated hyperventilation caused the influx of eosinophils, neutrophils and mast cells into the airways. cationic proteins (i.e. ecp) released by the eosinophils were suggested to be partly responsible for airway epithelial cell and connective tissue injury, which was still not healed after 24 hours. this repeated exposure resulted in stratified squamous epithelium (squamous metaplasia), replacing the normal ciliated epithelium. there was also an increase in the thickness of the airway lamina propia (sub-mucosal area) as well as goblet cell hyperplasia, possibly due to oedema relating to damage and an inflammatory response. the increase in squamous epithelium suggested that airway repair and remodelling was taking place. 8 the loss of airway epithelial cells was shown to be detrimental to normal airway function. these cells are an important source of prostaglandin e2 (pge2), which serves to inhibit cholinergic neurotransmission, smooth-muscle contraction, and mast cell degranulation. 22 a loss of airway ciliated epithelium and an increase in the thickness of the airway lamina propia result in impaired mucociliary clearance and accumulation of intraluminal debris, leading to the development of airway obstruction. these factors may all play a role in the pathological atopy-related responses of the airways. davis et al. 8 concluded that their results suggested that repeated exercise in cold weather could provoke changes in the airway morphology, leading to many of the common symptoms of asthma in athletes who did not previously suffer from this respiratory condition. although the evidence from this study is convincing, further research is required, specifically using human athletes. conclusions and recommendations for future research this review has provided a brief discussion of factors that may explain the development of pathological atopy-related responses in athletes. the literature suggests that hyperventilation during exercise, combined with exposure to cold air and/or to a mixture of allergens and pollutants, induces airway inflammatory responses and possibly airway remodelling which may be responsible for the development of asthma or ahr in elite endurance athletes. 17 the majority of the research has reported differences in inflammatory cell recruitment or activation in the airways of elite endurance athletes, at baseline or after exercise intervention, compared with controls. however, only recently have there been reports of the possible underlying mechanisms that explain the regulation of airway inflammatory responses 7 and how these airway inflammatory responses may result in pathological airway remodelling. 8 importantly, these two studies used animal models and future research should be performed to validate the proposed mechanisms in human studies. finally, future research should examine the effect of the exercise challenge itself on airway atopy-related and inflammatory responses in elite endurance athletes. while the literature seems to support the role of local airway conditions and/or events in inducing atopy-related symptoms in athletes, various researchers have proposed that alterations in the hormonal and/or cytokine milieu with intense competition and/or training may also play a role. 37,40 specifically, susuki et al. 41 have shown that the circulating lymphocyte population is biased toward th2 profile of cytokine secretion after exercise. this bias was related to the concurrent release of glucocorticoids during exercise, which promote a shift from a th1 to th2 cytokine profile. 11 recently, smith 36,37 proposed that the increased incidence of atopyrelated symptoms associated with strenuous exercise may be due to an altered focus of immune function. specifically, it was hypothesised that repetitive tissue trauma sustained during strenuous exercise training induces a systemic th2 cytokine profile. the consequence of the bias towards a th2 profile is the up-regulation of humoral immunity (hi). this implies the proliferation and differentiation of b-cells into antibodysecreting plasma b-cells; immunoglobulin (ig) class (isotype) switching from igm to igg1-4, iga or, in support of the argument in this review, ige; as well as eosinophil migration from the bone marrow to, and activation in, the airways. 33,34 as discussed earlier in this review, ige and eosinophils are crucial factors involved in promoting the airway inflammatory responses that occur in allergies and asthma. from the above discussion it is feasible to suggest that, in addition to local airway conditions and events, the exercise challenge itself may play a role in influencing atopy-related and inflammatory responses in the airways. research has yet to determine the exact impact of local and systemic factors on the airway responses of elite endurance athletes and hence, considerably more research is required in this area. pg46-51.indd 50 6/28/06 1:47:45 pm sajsm vol 18 no.2 2006 51 references 1. anderson sd, daviskas e. the mechanism of exercise-induced asthma is... j allergy clin immunol 2000; 106: 453-9. 2. anderson sd, togias ag. dry air and hyperosmolar challenge in 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athletes: atopy and sport event as risk factors. j allergy clin immunol 1998; 101: 646-52. 21. karjalainen e, laitinen a, sue-chu m, altraja a, bjermer l, laitinen la. evidence of airway inflammation and remodeling in ski athletes with and without bronchial hyperresponsiveness to metacholine. am j respir crit care med 2000; 161: 2086-91. 22. kleeberger sr, freed an. prostanoids. in: busse ww, holgate st, eds. prostanoids. boston: blackwell scientific publications, 1995: 825-37. 23. langdeau j, boulet l. prevalence and mechanisms of development of asthma and airway hyperresponsiveness in athletes. sports med 2001; 31: 601-16. 24. langdeau j, turcotte h, bowie dm, jobin j, desgagne p, boulet l. airway hyperresponsiveness in elite athletes. am j respir crit care med 2000; 161: 1479-84. 25. larsson k, tornling g, gavhed d, muller-suur c, palmberg l. inhalation of cold air increases the number of inflammatory cells in the lungs in healthy subjects. eur respir j 1998; 12: 825-30. 26. lazaar al, panettieri ra. is airway remodeling clinically relevant in asthma? am j med 2003; 115: 652-9. 27. linn ws, venet tg, shamoo da, et al. jd. respiratory effects of sulphur dioxide in heavily exercising asthmatics. am rev respir disease 1983; 127: 278-3. 28. morici gbm, riccobono l, insalaco g. markers of airway inflammation in non-asthmatic swimmers at rest and after exercise. eur respir j 2001; 18: 491s. 29. muns g. effect of long-distance running on polymorphonuclear neutrophil phagocytic function of the upper airways. int j sports med 1993; 15: 96 9. 30. muns g, rubinstein i, singer p. neutrophil chemotactic activity is increased in nasal secretions of long-distance runners. int j sports med 1996; 17: 56 9. 31. potts j. factors associated with respiratory problems in swimmers. sports med 1996; 21: 256-61. 32. rak s, bjornson a, hakanson l, sorensen s, venge p. the effect of immunotherapy on eosinophil accumulation and production chemotactic activity in the lung of subjects with 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and bronchial biopsies in crosscountry skiers. respiration 2000; 67: 417-25. 39. sue-chu m, larsson l, moen t, rennard si, bjermer l. bronchoscopy and bronchoalveolar lavage findings in cross-country skiers with and without “ski asthma”. eur respir j 1999; 13: 626-32. 40. suzuki k, nakaji s, yamada m, totsuka m, sato k, sugawara k. systemic inflammatory response to exhaustive exercise. cytokine kinetics. exerc immunol rev 2002; 8: 6-48. 41. suzuki k, yamada m, kurakake s, et al. circulating cytokines and hormones with immunosuppressive but neutrophil-priming potentials rise after endurance exercise in humans. eur j appl physiol 2000; 81: 281-7. 42. tikkanen ho, helenius i. asthma in runners. brit med j 1994; 309: 1087. 43. umetsu dt, akbari o, dekruyff rh. regulatory t cells control the development of allergic disease and asthma. j allergy clin immunol 2003; 112: 480-7. 44. weiler jm, layton t, hunt m. asthma in united states olympic athletes who participated in the 1996 summer games. j allergy clin immunol 1998; 102: 722-6. 45. wetter tj, xiang z, sonetti da, et al. role of lung inflammatory mediators as a cause of exercise-induced arterial hypoxemia in young athletes. j appl physiol 2002; 93: 116-26. 46. wilber rl. incidence of asthma and exercise-induced asthma. in: rundell kw, wilber rl, lemanske rf, eds. incidence of asthma and exercise-induced asthma. champaign, il: human kinetics, 2002: 39-68. pg46-51.indd 51 6/28/06 1:47:45 pm review 1 sajsm vol. 34 no. 1 2022 creative commons attribution 4.0 (cc by 4.0) international license sport supplement use among high school rugby players in south africa: a scoping review b harmse, bbio; h noorbhai, phd department of sport and movement studies, faculty of health sciences, university of johannesburg, johannesburg, south africa corresponding author: h noorbhai (habibn@uj.ac.za) rugby is a popular sport worldwide with an estimated 8.5 million players globally. the popularity of this sport is ever-increasing. [1] the popularity of this sport has extended to the south african youth with an estimate of 388 393 registered adolescent players under the age of 18 years old. [2] rugby is a contact team sport comprised of 15 players in various positional roles, namely: full-back, wing, centre, fly-half, scrum-half, number 8, flankers, hooker, props and locks. [3] the professionalisation of the sport that occurred during the 1990s has led to the significant increase in the level of competition between players, and this mindset has extended to the sporting level of the youth resulting is highly competitive high school rugby development. [1,4] this professionalisation has resulted in many young athletes aspiring to achieve certain body characteristics, such as increasing muscle size and strength to keep up with the demands of the sport. [4] this has related to the saying ‘bigger is better’, as a rugby player with significant body mass is believed to have greater influence on the game in terms of strength, speed and power. [2] according to the international olympic committee (ioc), a sport supplement is defined as any substance that is consumed by athletes for the purpose of improving their sporting performance. [5] many young athletes consume sport supplements for a variety of reasons, some of which include the desire to increase their muscle mass and body size or gain benefits in sport performance or strength. [6] it is of primary concern that an athlete is aware of the risks associated with the use of sport supplements, such as health risks or legal ramifications linked to doping. [7] the term ‘doping’ can be defined as the use of substances by athletes to gain a performance benefit. however, most of these substances are classified as prohibited substances by the world anti-doping agency (wada). [8] doping by athletes can be done purposefully; however, there are some athletes who unknowingly consume prohibited substances and this is regarded as un-intentional doping. [5] for a substance to be seen as a prohibited substance according to wada, it needs to be a substance that has been classified with performanceenhancing benefits, risks the athlete’s health and does not maintain the code of wada regarding the spirit of sport. [9] the sport supplement industry has been criticised due to its poorly regulated production of sport supplements which possibly lead athletes to unintentionally doping, and subsequently failing to comply with wada. a review of the available literature regarding the general prevalence of sport supplements used by adolescent rugby players and the general attitudes towards sport supplement use in south africa is imperative for investigation. review of the current literature prevalence of sport supplement use in athletes globally, the use of sport supplements has increased by 5.8% annually in all types and levels of sport. [7] approximately 30% to 95% of athletes consume a sport supplement. the broad percentage range is due to the variations in the different types background: the use of sport supplements has increased for all types and levels of sport, with an estimated increase of 5.8% annually. sport supplement usage and doping among high school athletes has increased over the years to meet the demands of the sports. objective: this scoping review identifies the trends and gaps in current literature regarding sport supplement use among high school rugby players in south africa. methods: a search was conducted using six electronic databases, namely oxford academic, emerald publishing, researchgate, sabinet, pubmed and google scholar. the eligibility of the articles was determined by means of a prisma flow diagram with the following inclusion criteria: (1) research concerning supplement use among rugby players, (2) research concerning supplement use among high school rugby players. five articles all comprising of cross-sectional study designs were included in this scoping review. results: the prevalence of sport supplement use among adolescent rugby players ranged from 30% to 45%. protein supplements (31% – 79%) were the most commonly identified supplement used among adolescent rugby players with the aim to improve sport performance as the most common reason for use. the internet (74%) and magazines (72%), followed by coaches comments (28% to 30%), were given as the most common sources of information. conclusion: the use of sport supplements is increasing among high school athletes due to the belief that these substances will provide sporting performance benefits or enhance the competitive ‘edge’ of these athletes. additional education regarding the safety of supplements is necessary to lower the incidences of doping among young athletes and avoid the adverse health effects that uncontrolled supplement use can cause. keywords: doping, ergogenic aids, nutrition, youth, athletes s afr j sports med 2022;34:1-9. doi: 10.17159/2078-516x/2022/v34i1a13348 mailto:habibn@uj.ac.za)%7c http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13348 https://orcid.org/0000-0001-9464-6854 https://orcid.org/0000-0002-5405-2100 review sajsm vol. 34 no. 1 2022 2 of athletes in terms of the sport, the level of play and demographical information. however, this particular study identified that 65% of the participants who play rugby for the spanish rugby federation consumed sport supplements. [10] studies performed in south africa concerning the use of sport supplements have shown that an estimated 40% to 70% of the athletes indicated that they consume sport supplements. [11] a study conducted in germany found that the majority (91%) of elite german athletes consumed sport supplements, while in a study conducted on kenyan rugby league players, 15% of the players indicated that they consume dietary supplements. [12, 13] common types of sport supplements used by athletes research shows that there is a variety of different supplements that athletes use depending on their sport and level of training. [5] when comparing the predominant sport supplement consumed by professional rugby players in europe, it was found that the most common sporting supplement used by rugby players from the european super league, were protein supplements followed by creatine (64%), 56% of the participants used carbohydrate supplements, and only 36% used caffeine as a type of sport supplement. [14] whey protein and caffeine supplements were the predominant sport supplements consumed by rugby players in the spanish rugby federation, namely 44% and 42%, respectively. this is followed by energy supplements (energy drinks and bars) which ranged from 34% to 38% of the participants. [10] when considering rugby players on the african continent, a study of rugby player participation taking part in the kenyan rugby league, 50% of the players used creatine monohydrate as a sport supplement followed by a whey protein supplement (33%). [13] in a study on the common types of sport supplements consumed by the under-21 blue bulls rugby players in south africa, it was found that the most common sport supplement consumed them was protein supplements (50%) followed by amino acids (31%). [15] common sources of information regarding the use of sport supplements in athletes according to a study by mccreanor et al. the most common source of information for sport supplements is the internet. [16] a sport trainer was the most popular source of information regarding the use of sport supplements in a study conducted by sánchez-oliver et al. [10] the use of scientific literature as a source of information is low. this is problematic as it indicates that athletes are not referring to scientifically based information regarding the use of supplements. [17] common reasons for supplement use in athletes in a study conducted by sánchez-oliver et al. [10], the main reason for sport supplement usage in rugby players was to enhance their sporting performance during training and during matches, stated by 62% of the participants. it is possible that many young athletes make use of sport supplements due to poor body image or body satisfaction, which can be linked to the desire to use these sport supplements to increase body size and muscle strength to meet the demands of the sport that they participate in. [6] when questioned why the athletes used the sport supplements, 42% of the rugby players who were part of the kenyan rugby league felt that the sport supplements aided their performance. however, 45% of the surveyed participants indicated that the sport supplements did not influence their sporting performance, while 43% of the players indicated that they felt using sport supplements was unnecessary. [13] all the under-21 blue bulls rugby players who used supplements in the study, indicated that the main reason for them using sport supplements was to increase the size of their muscles, followed by increasing their energy levels posttraining or post-match (38%). [15] general attitudes concerning sport supplements usage in athletes in a study conducted on rugby players who participated in the european super league, it was found that the majority of the players were aware of the associated risks when using sport supplements. this information was contradicted when asked if they believed that the sport supplements that they regularly used were safe and correctly tested. [14] a study in france indicated that 90% of elite athletes viewed doping as an act of dishonesty and that it is dangerous for one’s health. [9] education regarding supplement use is a vital part of an athlete’s training with an increase in the desire to use sport supplements. however, there is limited emphasis on the need to improve education for young athletes to make informed decisions about sport supplements for the sake of their health and sporting careers. [18] in summary, education concerning sport supplements is vital not only to protect athletes against the risks from supplements but to also allow the athletes make informed decisions concerning the use of these supplements. educating athletes regarding optimal nutritional knowledge and maturation can lead to sport success instead of them risking the use of prohibited substances. methods this scoping review made use of the preferred reporting items for systemic reviews and meta-analyses (prisma) guidelines method to identify relevant articles. [19] a search was conducted to identify possible relevant studies using six databases (oxford academic, emerald publishing, researchgate, sabinet, pubmed and google scholar), as well as two additional resources (south african journal of sports medicine and the british journal of sports medicine). the search was conducted on the 16th september 2021. during the search for relevant articles, keywords such as ‘sport supplements’, ‘doping’, ‘adolescent athletes’, ‘high school rugby players’, as well as phrases such as ‘doping in athletes’, ‘doping in adolescents’, ‘doping in adolescent athletes’, ‘sport supplement use in athletes’, ‘sport supplement use in adolescent athletes’, ‘sport supplement use in rugby players’, and ‘doping in rugby players’ were applied. in addition, the search was limited to studies that included rugby players who used sport supplements. review 3 sajsm vol. 34 no. 1 2022 the inclusion criteria for this review  studies that included research concerning supplement use among rugby players.  studies that included research with sources of information concerning supplement use among rugby players.  studies that included research concerning supplement use among adolescent/high school rugby players. the exclusion criteria for the articles obtained for this review  articles removed based on unrelated topics/titles (articles that did not include supplement use in adolescent athletes).  articles that had a meta-analysis methodology.  articles that were published in a language other than english. once articles were identified from the above-mentioned databases, all duplicates retrieved were removed. all articles were screened and those not meeting the inclusion criteria were removed. the screening process was completed by means of the prisma method guidelines shown in figure 1. [19] in order to extract the relevant data from the eligible sources, the authors’ initials and surnames, year of publication, population size, age of the participants, prevalence of sport supplement use, common reasons for the use, common types of supplement used among rugby players, sources of information and the general attitudes and knowledge of the athletes regarding supplement usage among high school rugby players in south africa were identified. these were performed for each of the selected studies and tabulated individually according to the topic. the studies used in this scoping review were all conducted in south africa. data synthesis if the data present in the article met the inclusion criteria requirements, data related to the prevalence, use and attitudes towards sport supplement use among high school athletes was extracted by the author and set up in a microsoft excel chart (2016). information on the authors, date of publication, population size, prevalence of sport supplement use, common sport supplements used, common reasons for sport supplement use and key findings regarding the general attitudes towards supplement use and doping were extracted by the author and recorded. the recorded data was tabulated according to different topics and presented in the results section. results a total of 206 possible relevant articles were identified by searching six databases and 14 possible relevant articles were identified from two additional journals. the articles were tabulated and duplicate articles were removed. after the duplicate articles were excluded, 185 articles were screened by the titles and abstract to determine relevance of the selected articles of which 155 articles were excluded due to not meeting the inclusion criteria. a total of 30 full-text articles were screened for eligibility and the resulting articles used in this review were narrowed down to five articles. study design all the articles selected for this review were of a descriptive, quantitative, cross-sectional study design by means of selfadministered surveys distributed to the high school rugby players. one study was conducted for a period of four years (2009 to 2012), where participants were approached once a year at an annual rugby training camp. fig. 1. schematic of the process followed for the literature search according to the prisma guidelines id e n ti fi c a ti o n s c re e n in g e li g ib il it y in c lu d e d articles identified through database searching (n= 206) articles identified through other sources (journals) (n= 14) articles after duplicates removed (n= 185) articles screened (basis of titles and abstracts) (n= 185) articles excluded (unrelated/meta-analysis/ not english) (n= 155) full text articles assessed for eligibility (n= 30) full text articles excluded (based on relevance and exclusion criteria) (n= 25) studies included for qualitative synthesis (n= 5) review sajsm vol. 34 no. 1 2022 4 demographic information and location of studies the age of the participants in the selected articles was between 15 to 18 years. all the participants played rugby at high school level, and were generally in the first or second teams of their high schools. half of the studies (n = 2) took place in the gauteng province of south africa, a single study took place in the western cape province of south africa, another study took place in kwazulu natal, with the remaining study including participants across different regions in south africa. prevalence of sport supplement usage according to the identified studies (table 1), the prevalence of supplement use among the participants ranged between 30% and 45%, with one study indicating that 3.9% of the participants used banned/prohibited sport supplements. one study did not identify a specific number of rugby players who made use of sport supplements as a separate topic. however, the prevalence of the different types of supplements used by the athletes were described in the study. type of supplements used by athletes and reasons for their usage there were varying types of commonly used supplements used by athletes according to the type of supplements listed in the surveys of the studies. table 1 summarises the most common supplements used by rugby players in the reviewed studies. in the first study by gradidge et al. [20], the most common supplement used (classified as a banned substance) was a growth hormone, where 5% of the participants indicated that they made use of this supplement. the second most commonly prohibited substances used by high school athletes was adrenaline and anabolic steroids, and 4% of participants used these banned substances, respectively. when surveyed regarding the use of unbanned sport supplements, 61% of the participants indicated that they used protein supplements as well as vitamin supplements. creatine supplement use was the least popular supplement used among high school athletes in johannesburg. the study conducted by nolte et al. [21] identified that 29% of the participants indicated that they used dietary supplements, however, no specific supplements were indicated. almost a quarter of the participants (24%) indicated that they use anabolic steroids. the use of protein supplements was the most commonly reported supplement used among high school athletes, with 31% of the participants stating that they use these supplements, based on the review study by duvenage et al. [22] in the study conducted by jooste [23], carbohydrate supplementation was the most commonly used sport supplement among rugby players (92%), followed by the table 1. sport supplement use, type and sources of information among high school rugby players in south africa author (year) number of participants prevalence of sport supplement use common types of supplements used source of information gradidge et al. [20] 100 (37% rugby players) 30% of the athletes use sport supplements. common substances use (prohibited) growth hormone (5%), anabolic steroids (4%), adrenaline (4%), insulin (2%). common substances used (nonprohibited)protein supplements (61%), vitamin supplements (61%), caffeine supplements (57%), carbohydrate supplements (54%), creatine supplements (32%). internet (74%), magazines (72%), friends (66%), coach (60%), parent (33%), personal trainer (33%), information brochures (31%), newspapers (29%), pharmacist (24%), tv and school (23%), sibling (19%), biokineticist (16%), books (16%), physician (10%), journals (9%). nolte et al. [21] 346 (6% rugby players) 45% of the participants indicated that they use sport supplements, 3.9% of the participants indicated that they were using banned substances. 29% of the participants indicated that they use allowed dietary supplements, however no specific supplements were indicated. 24% indicated that they use anabolic steroids. coaches (30%), parents (19%), friends (17%), other athletes (16%), south african institute for drug-free sport (11%), other (8%). duvenage et al. [22] 198 (all played rugby) 42% of the participants indicated that they used sport supplements. protein (31%), meal replacements/recovery formulas (16%), creatine (16%), carbohydrate (12%), vitamin (10%), pre-workout (5%), glutamine (3%), omega 3/omega 6 fatty acids (3%), non-specific (2%), other (2%), amino acids (1%), fat burners (>1%). no information regarding the common sources of information used by athletes was present in this study. jooste [23] 189 (all played rugby) this study divided the prevalence of supplement use according to the most common type and the difference between two rugby league players. carbohydrate (92%), protein (79%), creatine (37%), glutamine (37%). coaches (28%), trainer (19%), supplement rep (16%), friends (15%), pharmacist (7%), parents (6%), doctor (4%), dietician (4%). strachan [24] 68 (all played rugby) 54% of the participants use sport supplements. protein (43%), creatine (22%) friends (32%), supplement representatives (22%), gym (19%), magazines (19%), coaches (5%). review 5 sajsm vol. 34 no. 1 2022 use of protein supplements (79%). creatine (37%) and glutamine (37%) were the least common supplements used by the rugby players. high school rugby players in kwazulunatal indicated that the most common supplement used among the team players were protein supplements (43%) while the least common sport supplement consumed was strength boosting supplements and the supplement nitric oxide (3%). [24] only three studies included questions regarding the most common reasons for rugby players making use of the sport supplements. the majority of the participants indicated that they used them to improve or enhance their sporting performance with a total of 68% of the participants in a study conducted by gradidge et al. [20]. the least common reason for using the supplement was the fear of not considered being part of the rugby team. when questioned on the reason for using specific supplements, the most common reason for the use of carbohydrate supplements was to lower the risk of fatigue and shorten the recovery time after play. the most common reason for using protein supplements among high school rugby players was to increase muscle size and muscle strength in order to improve sporting performance. [23] in the study conducted on high school rugby players in kwazulu-natal, the most common reasons for using protein and creatine supplements was to increase the strength of the muscles and the muscle mass of the athletes, resulting in athletes increasing in body size. [24] source of information regarding sport supplements emanating from research studies the least common source of information regarding sport supplements that adolescent rugby players consulted regarding their use and safety were dieticians, with one study indicating that 4% of the participants consulted a dietician (table 1). in another study, the participants indicated that the internet (74%) and magazines (72%) were the sources that they relied on to obtain information regarding using sport supplements. in two studies, coaches were the most common source of information for supplement use, with up to 30% of the participants in the study by nolte et al. [21] and 28% of the participants in the study by jooste [23] indicating that they approached their coach for information. only 16% of the participants in the study conducted by gradidge et al. [20] indicated that they approached a biokineticist for information about the use of sport supplements. the most common source of information among rugby players in kwazulu-natal was information from the player’s friends. [24] general attitudes towards sport supplements in the study conducted by gradidge et al. [20], 91% of the participants indicated that they felt the use of sport supplements among high school athletes is increasing in south africa with 37% of the rugby players surveyed believing that their use is on the rise while the majority (84%) felt that learners are being pressured into using these supplements in high school sport. thirty-seven percent of the participants agreed that they felt tempted to use performance enhancing supplements; however, 27% of them said that they never considered using sport supplements noted during the review of the study by gradidge et al. [20] a similar view was stated in the study by nolte et al. [21] with 39% of the participants indicating that they would consider using supplements (nonprohibited) to improve sporting performance, and more than half (70%) indicated they would not use banned/prohibited substances to improve sporting performance. when considering specific types of sport supplements used by athletes, 68% of the participants believed that they would use a protein supplement for the purpose of improving muscle size. [22] in a study by jooste [23], players stated that they were more likely to use carbohydrate supplements (91%), followed by protein supplements (90%), glutamine (59%) and creatine (57%) in the future. based on the study by gradidge et al. [20], 61% of the participants indicated that they felt that the use of sport supplements was unethical, which is similar to the view by the participants in the study by nolte et al. [21] the majority of the participants (85%) stated that prohibited substances were harmful to one’s health while 84% indicated that using banned substances to improve performance was morally wrong. however, it was noted in the study by gradidge et al. [20] that the majority of the participants (91%) indicated that they believed that the selling of banned substances should not be banned in sport. more than half (59%) of the participants in the study by nolte et al. [21] indicated that there is not sufficient education on the safety and dangers regarding the use of sport supplements, particularly banned substances. this finding was, however, contradicted in the study by gradidge et al. [20] where 81% of the participants indicated that there is no requirement for more education on the use of prohibited substances and doping. in the same study, 91% of the participants stated that there is no requirement for stricter ramifications or punishments for doping in sport. in the study conducted by gradidge et al. [20], almost threequarters (72%) of the participants stated that they did know which substances were banned according to wada, while according to the study by nolte et al. [21], 74.8% of the participants felt that they were well-informed about the substances classified as banned in their sport. more than half of the participants (55%) indicated that the use of regular doping control testing in high school sport would lower the instance of prohibited supplement use, and only 48% of the participants indicated that they believed more tests for doping should be conducted. in the study conducted by duvenage et al. [22], 60% of the participants stated that they believed that using sport supplements will not lead to a positive doping control test. overall, knowledge regarding the safety and correct labelling of supplements and the belief that supplements are the best way to achieve bigger muscles was considered poor (43%). [23] only 48% of the players agreed that natural sources of protein found in food is better than that found in supplements; however, there is a similar average in the study by duvenage et al. [22] with 40% of the participants believing that the source of protein found in foods is of a higher quality than that found in sport supplements. thirteen percent of the athletes agreed that muscle mass gain is not linked to creatine review sajsm vol. 34 no. 1 2022 6 supplementation. less than 5% of the players agreed that glutamine supplements are not effective in sport performance for athletes. [24] twenty-two percent of the high school rugby players indicated that they would try a banned substance to improve their performance. [23] discussion this scoping review identified that there are very few studies conducted on sport supplement use among high school rugby players in south africa. the use of sport supplements with the aim to improve performance is an age-old tale that can be traced back to the third century bc, where evidence was found that the athletes of that era made use of substances that improved their sporting performance, with additional information identifying that supplement use was prevalent among greek olympians in 776 bc. [7, 25] as mentioned, sport supplements are often used by athletes to improve sport performance, and different sport supplements have different physiological effects and adaptations that result in improvements in sport. when considering the most prevalent sport supplements used by athletes in this scoping review, protein supplements were used to improve sport performance by increasing muscle size and strength. protein supplements provide increases in protein synthesis and lowers the rate of degeneration of proteins in the skeletal muscles. [26, 27] the increase in protein synthesis results in increases in muscle size and strength which would be beneficial to athletes, particularly rugby players, to meet the requirements of the sport. [26] carbohydrate supplements are generally used by athletes to increase their energy before, during and after training, as well as for preand postmatch energy. in addition, caffeine is a stimulating substance that increases central nervous systems activation. however, caffeine is linked to increases in a person’s heart rate and blood pressure, and may result in an increased sense of anxiety and sleep abnormalities which may negatively impact athletes’ sporting performance. [27, 28] the use of banned substances such as anabolic steroids amongst high school athletes was identified in the study by nolte et al. [21] where 24% of the participants used this banned substance and 4% in the study by gradidge et al. [20] anabolic steroids have similar physiological effects on the body as protein supplements; however, anabolic steroids are a form of synthetic testosterone that increase protein synthesis, and as a consequence, increases lean body mass and muscle strength. anabolic steroids have many side effects that athletes are not always aware of, such as increases in low-density lipoproteins and mood disturbances, typically aggression. [27] sport supplements may have some benefits to sport performance; however, athletes should be aware of the side effects and how these supplements influence the body before deciding to use them. prevalence of sport supplements supplementation with the aim to enhance sporting performance has continued to increase over the decades in all sports with an estimated range of between 30% to 95% of athletes making use of a form of supplementation globally. [10] this wide range of the prevalence of sport supplements is dependent on the type of sport, the level of competition and the physical requirements needed to succeed in the sport in terms of strength, speed and agility, which is particularly prominent in sports such as rugby. [26] this demand and the professional level of the sport often leads to young athletes seeking additional sources to improve their sporting performance and generally sport supplements are the first line of action to achieve this. [25] it appears as if high school athletes, together with parents and coaches, have had a change in mind-set from playing for the love and enjoyment of the sport to athletes striving to excel in their sport in order to be the best player. this often leads the athletes to use sport supplements without always considering the safety and regulation of these supplements. [20, 24, 25] this is supported by evidence identified in the studies reviewed where the estimate range of sport supplement usage among high school athletes in south africa range from 30% to 54%. common types of sport supplements and reasons for their use the increased use of sport supplements has funnelled down to high school level sports in south africa (particularly in rugby) where there’s a desire among athletes to increase strength or change their body size to be a better player depending on the their position in their sport. [15] although some sport supplements may be ergolytic, they can also be ergogenic in which case they enhance exercise capacity and/or athletic performance. the continual rise of sport supplements usage may be attributed to some degree to body image dissatisfaction that is present in young adolescents as well as young athletes. this trend was evident in the study conducted by yager and o’dea [6] where only 30% of the athletes were satisfied with their body image and the remaining athletes indicated that they would want to be either larger or smaller. in the review of the study conducted by gradidge et al. [20], the majority of athletes believed that the use of sport supplements in high school athletes is increasing in south africa. this trend is evident when considering the reasoning behind the use of sport supplements among high school rugby players, particularly in south africa, where 68% of the participants who took part in the survey conducted by gradidge et al. [20] indicated that they used supplements to improve their sporting performance. in the review of the study by strachan [24], it was noted that more than half the rugby players (54%) decided to use protein supplements to increase their strength in order to play their sport. common sources of information regarding sport supplements advertising of sport supplements (whether on television, the internet or in magazines) may also contribute to the increase in their use due to the ‘hype’ created by using well-known athletes (or social media producers) by supposedly providing benefits of such supplements. however, these advertisements often include information that is biased in order to convince athletes to use the supplements and these athletes or coaches use this information to confirm the safety and benefits of the review 7 sajsm vol. 34 no. 1 2022 supplements. [24] athletes who use this information (which is often not scientifically sound) or approach coaches or teammates who have little knowledge of supplements may lead to the misuse of the supplements by using more of the recommended amount, which in turn can lead to health problems. this misuse is worsened by athletes not having sufficient knowledge to make informed decisions when reading the ingredients lists. [5,29] improving the general sources of information regarding sport supplements is essential as poor sources of information may lead to poor decisions regarding their use. it was identified that sources such as the internet, along with information from coaches and friends, were seen as the most common information sources used by high school athletes (in the studies reviewed). a range of 28% to 60% of athletes indicated that they consulted their sporting coach regarding the information concerning these sport supplements. this evidence is supported by a study conducted on high school rugby players in ireland where 66.9% indicated that they consulted with their coach regarding this matter. [30] the internet may be considered a beneficial source of information in terms accessibility and amount of information available. however, most sources on websites are not scientifically reviewed or correct which may lead to misinformation. [25] the use of scientific literature and knowledge of qualified healthcare practitioners, such as dieticians, are often not the first line of consultation when considering the use of sport supplements, with only 4% of rugby players in the western cape [23] indicating that they approached a qualified dietician for information. a similar finding is also found in the study by walsh et al. [30] where only 10 of the 203 rugby players consulted a qualified healthcare professional. this can be regarded as problematic in terms of obtaining the correct information on the safe use of sport supplements, as sources often used by athletes may be unreliable or not evidencebased, which may result in athletes using supplements that may be detrimental to their health and well-being. general attitudes towards the use of sport supplements there are often discrepancies between the general attitudes regarding the use of sport supplements and doping which may be linked to the educational gap as many players reported that more education of dietary requirements and supplementation are necessary. in the study conducted by walsh et al. [30], the majority of the adolescent rugby players felt that additional education regarding nutrition and the use of sport supplements would be beneficial as the participants in this study showed a poor understanding and knowledge about the correct nutrition for their age and the demands of their sport. a similar view was expressed by the athletes surveyed in the study by nolte et al. [21] where 59% of the participants felt that more education was required. however, this view was not shared by athletes in johannesburg high schools where majority of the athletes (81%) felt that there was enough education available regarding the use of these sport supplements. [20] the risk of doping is further increased due to the gap present in the knowledge of labelling and the identification of harmful ingredients which may lead to unintentional doping through the use of banned substances. the risk is also considered higher if the athlete’s attitude towards doping does not deter him/her not to make use of these supplements to improve performance or their body image. in the review of the study by duvenage et al. [22], more than half the participants (60%) believed that the use of banned substances or doping substances would not result in the athlete testing positive for doping. it was found that majority of the athletes that were part of the studies reviewed had a negative attitude towards the idea of the using banned substances. some athletes indicated that it was against good morals and was, therefore, considered unethical. protocols in dealing with punishments ranging from the removal of medals or personal/world records to a more severe punishment of suspending athletes from partaking in the sport for a period of time have been implemented by wada. [5] this level of punishment has led to many athletes believing that this is an effective means of deterring athletes from doping. athletes who were surveyed in the study by gradidge et al. [20] indicated that there was no need to increase the severity of the punishment linked to doping. according to the athletes surveyed in the study by duvenage et al. [22] less than half of the participants believed that more testing should be conducted in schools. however, 14% of the under-16 rugby players in south africa indicated that if there was a chance that they would not be caught by a positive doping control test, and they would consider using a banned substance. [22] this shows that athletes at a high school level are somewhat fearful of the consequences of being caught for doping but would still consider doping if there was a chance of not getting caught. the increase in usage of sport supplements in high school athletes is a matter of concern as the sport supplements industry is often under scrutiny due to the poor regulation of the production and the labelling of the products. [7] this is evident is the article by the international olympic committee where it was found that athletes who have been tested for doping and had a positive test, made use of sporting supplements that may have contained small amounts of prohibited substances which were not indicated on the product’s list of ingredients resulting in unintentional doping. [21] this may support the ‘gateway hypothesis’ where athletes using sport supplements may use other substances that may be banned, such as anabolic steroids, in the future thereby opening the door for positive doping control tests and dangers to the athlete’s health. [23] when surveyed regarding the knowledge of banned substances and the likely adverse side effects to the athlete and therefore meets the criteria according to wada for being a banned substance. [9] seventy-two percent of the athletes in south africa in the study reviewed by gradidge et al. [20] indicated that they were aware of what were banned substances according to wada, with a similar view in the study conducted by nolte et al. [21]. this would be considered as a positive attitude towards anti-doping awareness. however, it is important to note that in the same study[21], 3.9% of the surveyed athletes indicated that they currently use a form of banned substance, with 24% of the athletes stating that they had used anabolic steroids as a form review sajsm vol. 34 no. 1 2022 8 of supplementation. the gap in education concerning sport nutrition and performance needs to be addressed in order for athletes to meet the recommended dietary requirements to reduce the need of sport supplements. [30] it appears that many athletes make use of sport supplements as a means of substituting the missing nutrients of their diet. globally, many athletes believe that obtaining the necessary nutrients to perform well at sport can only be achieved through supplementation. this is a perception often supported by the parents of the athletes (as indicated by the parents of athletes in the east rand of johannesburg, south africa). [11, 30] this evidence is present in the viewpoints of the studies reviewed in this scoping review where less than half of the athletes surveyed stated that natural sources of nutrients (particularly protein sources) are deemed superior to that found in supplements. [22] limitations of the study in the present scoping review, there were very limited sources reviewed concerning the prevalence and general attitudes regarding the use of sport supplements among high school rugby players in south africa. however, findings from this review provides some insight into the general attitudes and prevalence of supplement use particularly in gauteng, western cape and kwazulu-natal provinces of south africa. conclusion the prevalence of sport supplement use is on the rise among all athletes, particularly among high school rugby players. the main reason for the use of sport supplements found in this review was to improve strength and sporting performance. this increase is linked to the heightened demands placed on the athletes by coaches, parents and the athletes themselves to have the ideal competitive ‘edge’ in order to be the best player or to be selected for the best team. an additional factor influencing young athletes to use sporting supplements is the desire to attain a certain physique, such as improved muscles size overcoming the low self-body image that is common among adolescents. a gap is present in the level of education regarding the use of sport supplements among high school athletes, with athletes believing that sport supplements are a necessary requirement to meet the nutritional needs of their sport. however, little knowledge is available regarding the health risks associated with the use of sport supplements as well as the risks of doping. the internet and coaches are the most commonly used sources of information for athletes regarding supplement use. information from scientifically reviewed literature and qualified healthcare professionals (such as dieticians) are less frequently consulted. this will lead athletes to believing information that is not reliable regarding the safety of the supplements they use which poses a great health risk with the potential of testing positive for banned substances and risking their sporting career. however, some athletes would consider using a banned substance if there was no testing and severe punishments associated with doping. further education should be deemed necessary regarding sport nutrition and the safety of using sport supplements. improvements in an athlete’s diet will ensure that these athletes achieve the required nutrients to aid their sporting performance. this will assist in decreasing the prevalence of sport supplement use among high school rugby players in particular and lower the overall incidence of doping in athletes. further research is required to document the prevalence of sport supplement use on a larger scale, in other countries, and using more studies. furthermore, a replication of this type of study would also be required in other types of sports in south africa. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: both authors contributed to the design of this research and the writing of the article ((i) conception, design, analysis, and interpretation of data; (ii) drafting or critical revision for important intellectual content; and (iii) approval of the version to be published). references 1. robinson b, pote l, christie c. strength and conditioning practices of high school rugby coaches: a south african context. s afr j sci 2019; 115(9-10): 92-97. 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[doi: 10.1123/ijsnem.21.5.365] [pmid: 21799215] sajsm vol 19 no. 5 2007 129 introduction the review of the cricket injury literature shows that three major cricket-playing countries have collected long-term injury data. in australia the surveillance revealed 886 injuries were sustained by players representing the national and state teams. these data were collected retrospectively from 1995 to 1998 and then prospectively from 1998 to 2005. in england the incidence and nature of injuries to professional cricket players reported 990 injuries that were recorded retrospectively from records of a professional county club by the team physiotherapist (1985 1995). in south africa 1 606 injuries to the national and provincial teams were reported prospectively by the physiotherapists and doctors working with the teams from 1998/99 to 2003/2004. while injury surveillance is fundamental to preventing and reducing the risk of injury, these studies used different injury definitions and methods of collecting and reporting the data, which prevented comparisons of injury rates between countries. as a result a consensus statement paper with regards to definitions and methods to calculate injury rates, incidence and prevalence, was developed in order to provide a standard which allows meaningful comparisons of injury surveillance data from different countries and time periods. this review evaluates the scientific research into cricket injuries, including long-term injury surveillance studies, the consensus statement paper for injury surveillance, specific cricket injuries countermeasures to reduce the risk of injury, cricket protective equipment, and finally identifies areas of future concern. studies using injury surveillance method the first study using this newly accepted injury surveillance method showed injury patterns in west indies domestic and national cricket teams, with more injuries having occurred when the national team was on tour than when playing at home. evidence of the effectiveness of injury prevention countermeasures was reviewed and reveals trials of interventions to reduce lower-back injury in fast bowlers. a 3year educational programme aimed at improving the bowling technique of young fast bowlers showed a reduction in the mixed bowling action, while a bowling harness showed no significant reduction in certain characteristics of the mixed bowling action. a prospective study to evaluate junior fast bowling workload guidelines found that in some cases the workload exceeded that suggested as appropriate for older original research article a review of cricket injuries and the effectiveness of strategies to prevent cricket injuries at all levels abstract objective. this review evaluates the scientific research on cricket injuries, including long-term injury surveillance studies, the consensus statement paper for injury surveillance, specific counter-measures to reduce the risk of cricket injuries and finally identifies areas of future concern. results. the literature shows that three major cricketplaying countries, australia, england and south africa, have collected long-term injury data. while these sets of data show definite trends, it was not always possible to make direct comparisons between data collected in various countries. as a result a consensus statement paper with regards to definitions and methods to calculate injury rates, incidence and prevalence was developed. the first study using this newly accepted injury surveillance method showed injury patterns in west indies domestic and national cricket teams. there have been three primary studies carried out with regards to interventions aimed at reducing the risk of injury to fast bowlers. these included a coaching interventions programme, the use of a bowling aid in an attempt to modify bowling technique and a study that evaluated the recommended bowling workloads in young cricketers. the implications of the changes to the laws relating to the bowling action and the increased usage of the sliding stop in fielding are reviewed. conclusion. from the review it is evident that there is a need to continue with injury surveillance, as well as a need to continue with and increase the number of studies that evaluate the efficacy of intervention strategies in order to reduce the risk of injury to cricketers. correspondence: r stretch sport bureau nelson mandela metropolitan university po box 77000 6031 port elizabeth tel: (041) 504-2584 fax: (041) 583-2605 e-mail: richard.stretch@nmmu.ac.za r a stretch (d phil) sport bureau, nelson mandela metropolitan university, port elizabeth pg129-132 .indd 129 1/11/08 11:08:41 am 130 sajsm vol 19 no. 5 2007 players and recommended that rest days should be added to the guidelines, as bowling more frequently than every 3 days increases the risk of injury. a brief review of the literature on the safety aspects of cricket batting equipment including helmets, gloves, pads and clothing, indicates that there are areas where improvements need to be made in order to reduce the risk of injury. the implications of the changes to the laws relating to the bowling action and the increased usage of the sliding stop in fielding, particular by young inexperienced cricketers, were reviewed. from the review it is evident that there is a need to continue with injury surveillance, as well as a need to continue with and increase the number of studies that evaluate the efficacy of intervention strategies in order to reduce the risk of injury to cricketers. world congress of science and medicine in cricket the world congress of science and medicine in cricket brings together a wide range of professionals including sport scientists, sports medicine specialists, physiologists, academics, administrators and coaches with an interest in cricket, from all major cricket-playing countries around the world. the aim of this congress, which is held every four years during the cricket world cup, is to provide a state-of-the art review of the basic, applied and clinical sciences as they relate to cricket and to offer a forum for integrating knowledge from the contributing sciences which address key areas in the prevention and management of cricket injuries and the enhancement of performance. this has contributed significantly to an increase in cricket research as sport scientists strive to assist players and coaches to achieve optimal performance in this competition. injury patterns long-term injury surveillance has been conducted in three studies in elite cricket in australia, 6 south africa, 8 and england 3 with the view off identifying injury patterns. retrospective injury information was obtained from the records of the team physiotherapist for the 54 cricketers who had played for the same county first team in england between 1985 and 1995. 3 an injury was defined as the onset of pain or disability caused while training for or playing cricket and which caused the player to seek medical attention. a total of 990 injuries were recorded, with an injury exposure of 17 247 days played and an injury incidence rate of 57.4 injuries per 1 000 days played. most injuries were sustained early in the season (april) when the least cricket is played. bowlers were the most susceptible to injury (70.1 injuries per 1 000 days), followed by the all-rounders, batsmen and wicket-keepers with 55.0, 49.4 and 47.3 injuries per 1 000 days, respectively. muscle/tendon strains, contusions/haematomas and ligament/joint sprains were found to be the most common injuries. most injuries occurred to the lower limbs (45%), followed by the upper limb (29%), trunk (20%) and head and neck (6%). the thigh and calf (25%), fingers (14%) and lumbar spine (11%) were the sites most vulnerable to injury. of the thigh and calf injuries, 72% were muscle/tendon strains and tears. finger injuries consisted mainly of contusions (40%), fractures and dislocations (29%) and ligament /joint sprains (23%). of the lumbar spine injuries, 63% involved ligaments and joints, while knee injuries were primarily ligament and joint sprains (28%), tendonitis (27%) and contusions (16%). the primary foot and ankle injuries were contusions/haematomas (41%) and ligament/joint sprains (29%). in a study in south africa 8 1 606 injuries in 783 cricketers were reported prospectively by the physiotherapists and doctors working with the national and 11 provincial teams over a 6-season period from 1998/99 to 2003/2004. the data collection, using a questionnaire, included biographical data as well as information about the anatomical site of injury, month of injury, activity performed when injured, the diagnosis and mechanism of injury and the recurrence of the injury. more injuries occurred during first-class matches (32%) with limited-overs (26%) matches and practices and training (27%) resulting in a similar number of injuries, while 15% were of gradual onset, which may have been as a result of a combination of factors such as training, practising and playing matches over a period of time. the chronicity of injuries showed that the majority of injuries were classified as acute injuries (65%), with chronic (23%) and acute-onchronic (12%) making up the balance. the injuries occurred during the pre-season (11%) (september), the early part of the season (35%) (october and november), mid-season (18%) (december and january), in the latter part of the season (16%) (february and march) and during the ‘off-season’ (20%) (april august). first-time injuries accounted for 65%, while recurrent injuries from the previous season made up 22% of the injuries. the recurrent injuries were primarily as a result of bowling (38%), overuse (23%) and fielding (18%). the rate of injuries sustained during the season and recurring again during the same season accounted for 12% of the total injuries. lowerlimb injuries accounted for nearly half of the injuries (49%), with the upper limb (23%), back and trunk (23%) and head, neck and face (5%) making up the balance. bowling (40%) and fielding and wicket-keeping (33%) accounted for the majority of the injuries, with batting accounting for 17% of the injuries sustained. of the bowling injuries, 55% were lower-limb injuries and 33% were back and trunk injuries. of the 39 stress fractures 79% were overuse bowling injuries, with the younger players sustaining 74% of the stress fractures. the primary mechanism of injury was the delivery and follow-through of the fast bowler (25%), running, diving, catching and throwing the ball when fielding (23%) and overuse (17%), various batting situations such as being struck while batting (7%), running between the wickets (4%) pg129-132 .indd 130 1/11/08 11:08:42 am sajsm vol 19 no. 5 2007 131 and batting for long periods at a time (4%), training (4%) and participating in various other sports (3%). the 1 606 injuries sustained were made up mainly of softtissue injuries consisting predominantly of muscle injuries (strains (491); tears (74); spasms (101); haematomas (85)), tendon injuries (tendonitis (107); tears (44)), ligament sprains (76), fractures (63) and stress fractures (39), joint injuries (rotator cuff (50); impingements (42); dislocations (8)). information on injuries to australian state and national cricketers was collected retrospectively for the first 3 seasons (1995 1996 season to 1997 1998 season) years and then prospectively for the next 7 seasons (1999 2000 season to 2004 2005 seasons). 6 the definition of injuries was an injury or medical condition that prevents a player being available for selection for a match or causes a player not to be able to bat, bowl or keep wicket during a match. of the 886 injuries recorded, 92% were new injuries, while 8% were recurrent injuries. of these, 52% occurred during major matches. the injuries were sustained while bowling (45%), batting (21%), fielding (23%) and wicket-keeping (2%). the balance of the injuries (9%) either occurred gradually or in unknown activities. lower-limb injuries accounted for nearly half of the injuries (49.1%), with the upper limb (24.5%), back and trunk (18.6%), head, neck and face (4.3%) and illness (7.3%) making up the balance. the mean seasonal injury match incidence (injuries/ 10 000 player hours) was reported for domestic 1-day (38.5), first-class (27.3), odi (59.8) and test (31.4) matches. fast bowlers miss about 16% of potential playing time through injury while for other positions it is less than 5%. there is an increased non-significant risk of injury when bowling in the second innings of a 1-day match, while a significant risk for the second innings of a first-class match as compared with the first innings. further, bowling after enforcing the follow-on in a test match is associated with an increase in injury. there is an increased risk of injury when bowling in the second match of back-to-back matches where there is less than 1 and 3 days for 1-day and first-class matches, respectively. while these data collected over an extended period show definite trends, it was not always possible to make direct comparisons between data collected in various countries. following the 2nd world congress of science and medicine in cricket that was held in south africa in 2003, a method of injury surveillance for international cricketers has set out definitions and methods of calculating injury rates which would allow comparisons to be made between countries and will assist in the identification of injury trends and risks on a broader scale which will further benefit the cricketers. 7 the first reported study using the internationally agreed injury surveillance protocol, 7 as well as the first published study on west indies cricket injuries, reported that 33 international and 162 domestic cricketers sustained 79 injuries. 4 of these injuries, 50 led to part of a match being missed and were thus used for match injury incidence and prevalence calculations. most injuries were sustained in test and first-class matches (40%) and 1-day matches (28%), with 28% sustained in activities outside of matches. new injuries accounted for 80% of the total number of injuries, with recurrent injuries from the previous season (10%) and the same season (10%) making up the balance of the injuries sustained. bowlers (46%) and batsmen (40%) were found to be at the greatest risk of injury, with the balance of the injuries sustained by the all-rounders (10%) and wicket-keepers (4%). muscle injuries (26%) most common, followed by ligament injuries (12%), stress fractures (12%) and fractures (10%). two players were struck by lightning in the same match. injury incidence for test and 1-day international (odi) matches (48.7 and 40.6 injuries per 10 000 player-hours for test and odi matches, respectively) was lower for home matches (31.1 and 23.1 injuries per 10 000 player-hours for test and odi matches, respectively) than away matches (61.3 and 50.2 injuries per 10 000 player-hours for test and odi matches, respectively). the injury incidence for domestic first-class and limited-overs matches was 13.9 and 25.4 injuries per 10 000 player-hours, respectively. the prevalence of injury for test and odi matches (11.3 and 8.1% of players unavailable for selection due to injury, respectively) was lower for both home tests and odi matches (7.3% of players unavailable for selection for both test and odi matches due to injury) than away matches (14.2 and 8.6% of players unavailable for selection due to injury for test and odi matches, respectively). these studies briefly have shown that injury data have been collected since the mid-1980s in four of the major-cricket playing countries. however, while the internationally accepted consensus paper agreeing on the method of collecting injury data will allow comparisons between studies conducted throughout the world, limited intervention studies have been carried out in an effort to reverse the injury pattern. intervention studies three primary studies carried out with regards to interventions aimed at reducing the risk of injury to fast bowlers. these included a coaching interventions programme, 2 the use of a bowling aid in an attempt to modify bowling technique 10 and a study that evaluated the recommended bowling workloads in young cricketers. 1 the 3-year coaching educational intervention study 2 consisting of two groups of young fast bowlers demonstrated that small-group coaching significantly reduced the level of shoulder alignment counter-rotation, as well as the incidence and progression of lumbar disk degeneration in young fast bowlers. there was a concurrent reduction in the number of bowlers using a mixed action. bowlers with either a front-on or side-on action (n=49) had significantly lower levels of lumbar disk degeneration (n=1) compared with 20 of the 94 mixedaction bowlers who sustained a lumbar disk abnormality. a third of the subjects continued to employ shoulder rotation pg129-132 .indd 131 1/11/08 11:08:42 am 132 sajsm vol 19 no. 5 2007 beyond the recommended level after the intervention ceased. the results indicated that technique modification using an education process decreased the incidence and/or progression of lumbar spine disk degeneration, but more specific and intense individual coaching should further reduce the risk of injury. a bowling harness, which was designed to modify bowling technique, was assessed as a means of modifying bowling technique in young bowlers. 10 no statistically significant effect on mean shoulder alignment counter-rotation, mean lateral flexion angle, mean flexion-extension angle of the trunk resulted due to the coaching programme. a decrease in the use of the side-on mixed bowling action was found in the group using the bowling harness. bowling with the harness forced the bowler to adopt a position at back-foot impact that reduced the torque in the spine. however, during the delivery phase no restricts on other aspects of trunk movement previously associated with back injuries were found. the effect of the harness did not extend beyond the cessation of harness wearing. it was recommended that the harness be re-configured in an attempt to control the shoulder separation angle at back foot impact as well as counter-rotation of the shoulder at front foot strike. 10 young cricketers (12 and 17 years) playing club and district cricket were monitored over a season in order to evaluate the appropriateness of bowling workload guidelines set by the australian cricket board. 1 all bowlers underwent a magnetic resonance imaging (mri) scan at the start of the season and then immediately after any back or trunk injury. they were required to maintain a logbook where they recorded any injuries and their bowling workload. bowlers tended to conform to the recommended number of deliveries to be bowled per match day, but bowled in excess of the recommended guidelines for practice sessions. of the 44 bowlers, 11 reported over-use bowling-related injuries, with 7 sustaining back injuries. the study showed a relationship between a high bowling workload and injury. the injured players bowled more frequently and had shorter rest periods between bowling sessions (3.2 days) than the uninjured (3.9 days). the bowlers with an average of ≥3.5 rest days between bowling were at a significantly less risk of injury than those with an average of <3.5 rest days. further, the results showed an increase of risk for the bowlers who bowled ≥50 deliveries per day or who bowled on average ≥2.5 days per week. from the above it is evident that the various strategies and interventions carried out have shown some success in reducing some risk factors associated with back injuries in fast bowlers. however, recent law changes to the game now allow a legally bent arm action, with or without elbow extension, during the delivery phase. this has allowed the bowler to increase the ball speed/spin through internal rotation of the upper arm. while the traditional bowling technique causes low levels of varus and valgus torques and flexion torques at the elbow joint in order to provide stability, 5 the law changes have increased the injury potential as the upper arm internal rotation results in excessive varus torques, similar to those in baseball pitching. torques generated by ligament and capsule results in the potential for increase in injury and may require changes to bowling guidelines to prevent elbow damage. 5 a further area of concern is the potential risk of injury to cricketers using the relatively new sliding stop technique. 9 this requires the fielder to chase the ball which is slightly to the left, in the case of a right handed thrower. the fielder then slides with the right leg extended and the left knee flexed under the right leg, sliding on the left buttocks and hip area with the left hand used for balance. the ball is then picked up with the right hand, the right foot is engaged with the ground and the left hand pushes on the ground to bring the fielder upright and in position to throw. the sliding stop may have advantages at higher level of the game, but at the lower levels, particularly at school level, the correct technique is not taught and/or practised and may predispose to injury. 9 if the right foot is not engaged and the left hand not used to push up it may result in the left leg having to be extended while weightbearing with the rotational forces used to pivot on the left knee resulting in a meniscal tear. the sliding technique should be discouraged as a means of fielding in cricket unless appropriately coached. 9 conclusion from the review it is evident that there is a need to continue with injury surveillance, as well as a need to continue with and increase the number of studies that evaluate the efficacy of intervention strategies in order to reduce the risk of injury to cricketers. further, before law changes are introduced by cricket administrators, this needs to be thoroughly investigated to ensure that the risk of injury to cricketers is not increased. reference 1. dennis rj, finch cf, farhart pj. is bowling workload a risk factor for injury to australian junior cricket fast bowlers? br j sports med 2005; 39: 834-46. 2. elliott b, khangure m. disk degeneration and fast bowling in cricket: an intervention study. med sci sport exerc 200; 34(11): 1714-18. 3. leary t, white j. acute injury incidence in professional country club cricket players (1985-1995). br j sports med 2000; 34:145-7. 4. mansingh a, harper l, headley s, king-mowatt j, mangsingh g. injuries in west indies cricket 2003-2004. br j sports med 2006; 40: 119-23. 5. marshall rn, ferdinands r. the biomechanics of the elbow in cricket bowling. int sports med j 2005; 6(1): 1-6. 6. orchard j, james t, alcott e, carter s, farhart p. injuries in australian cricket at first class level 1995/1996 to 2000/2001. br j sports med 2002; 36: 270-5. 7. orchard j, newman d, stretch r, frost w, mansing a, leipus a. methods for injury surveillance in international cricket. j sports sci 2005; 8(1): 1-14. 8. stretch ra, venter djl. cricket injuries – a longitudinal study of the nature of injuries to south african cricketers. s afr j sports med 2005; 17 3): 4-9. 9. von hagen k, roach r, summers b. the sliding stop: a technique of fielding in cricket with a potential for serious knee injury. br j sports med 2000; 34: 379-81. 10. wallis r, elliott b, koh m. the effect of a fast bowling harness in cricket: an intervention study. j sports sci 2002; 20(6): 495-506. pg129-132 .indd 132 1/11/08 11:08:43 am introduction the aetiology of tendon failure in rotator cuff disease is generally considered to be multi-factorial. this includes extrinsic factors such as repetitive low-velocity micro-trauma and compression of the cuff by an abnormal coraco-acromial arch, and intrinsic factors such as poor cuff vascularity, alterations in collagen and age-related changes. furthermore, it is generally believed that most full-thickness rotator cuff tears occur in the setting of already degenerated tendons, even when associated with trauma. 4-6,8,9,12,14-16 the prevalence of tears is reported to be 30% in people older than 60 years, 50% in people at 70 years and more than 80% in people at 80 years. 16 van holsbeeck et al. 16 reported these ultrasound findings in 90 volunteer subjects who had never sought medical attention for shoulder disease. they showed no statistically significant differences in the prevalence of rotator cuff lesions in each gender for the dominant or non-dominant arm. they also found no statistically significant differences in the incidence of rotator cuff lesions related to gender or reported level of exertional activities. however, the prevalence of rotator cuff tears in both dominant and non-dominant arms showed a linear increase after the fifth decade of life. these results indicate that rotator cuff lesions may be regarded as a natural correlate of aging, with a statistically significant linear increase after the fifth decade of life. 1,3,6,7,10,13,14,16,17 with the use of fluoroscopy, burkhart 3 concluded that the location rather than the size of the tear might be a more important factor in the resultant glenohumeral mechanics. original research article ultrasound study of the asymptomatic shoulder in patients with a confirmed rotator cuff tear in the opposite shoulder z oschman (mb chb, dch, msc (sports medicine))1 c janse van rensburg (mb chb, mmed (phys med), msc (sports medicine))1 n g j maritz (mmed, fcs (orth) sa)2 h boraine (phd)3 r owen (bsc (hons))3 1 division of sports medicine, department of orthopaedics, university of pretoria 2 department of orthopaedics, university of pretoria 3 department of statistics, university of pretoria abstract objective. to document the incidence of asymptomatic rotator cuff tears in patients with a confirmed symptomatic tear in the opposite shoulder, and to identify ultrasound findings that may distinguish symptomatic from asymptomatic tears. design. when patients are referred for an ultrasound examination for the confirmation of symptomatic rotator cuff tear the opposite shoulder is often used for comparison. however, patients often have a similar tear on the asymptomatic side. fifty patients with a confirmed symptomatic rotator cuff tear and an asymptomatic shoulder on the opposite side were chosen for inclusion. the patients were examined using a siemens sonoline elegra 7.5 mhz linear multi-frequency probe. the appearance of the rotator cuff, long head of the biceps and the subacromial-subdeltoid bursa (sasd bursa) were documented. the antero-posterior (ap) dimension of the supraspinatus muscle and fat between the trapezius and supraspinatus muscles were measured, which indicated if a tear was acute or chronic. the width and length of the rotator cuff tear were measured. setting. division of sports medicine, university of pretoria. results. fifty-four per cent of the asymptomatic shoulders had tears. we found that the symptomatic tears were larger, appeared more chronic and had an associated biceps tendinopathy and glenohumeral joint effusion. correspondence: z oschman po box 2090 groenkloof pretoria 0027 tel: 012-343 5000 fax: 012-343 0277 e-mail: zanet@mweb.co.za conclusion. as other authors have found, the high incidence of asymptomatic tears indicates that rotator cuff tears can be regarded as a natural correlate of aging and that bilateral tears are common. initial treatment should be conservative, but larger tears may benefit from early surgery before becoming chronic and causing glenohumeral dysfunction. sajsm vol 19 no. 1 2007 23 pg23-28.indd 23 4/4/07 9:50:59 am 24 sajsm vol 19 no. 1 2007 findings on ultrasound that may distinguish asymptomatic from symptomatic tears have not been established. the aim of this study was to document the incidence of asymptomatic tears in patients with a confirmed symptomatic tear on the contralateral side and to look for any findings on ultrasound that may distinguish symptomatic from asymptomatic tears. material and methods the shoulders of 50 patients, 32 males and 18 females, with an average age of 64 years (range 40 83 years) were studied. the patients had a confirmed symptomatic rotator cuff tear on the one side and an asymptomatic shoulder on the contralateral side. the asymptomatic shoulder had no history of problems severe enough to have required medical attention. the patients completed a questionnaire regarding gender, age, race, history of shoulder pain, stiffness, weakness or any limitations on athletic activities or activities of daily living. all patients gave informed consent. the accuracy of ultrasound in the assessment of full-thickness rotator cuff tears is well established in the literature. studies carried out since 1986 show a consistent pattern with both high sensitivity and specificity particularly over the past 5 years, a trend reflecting improvements in ultrasound technology. 11 it is also a well-known fact that an ultrasound examination is operator-dependent. all the examinations in this study were done by the same experienced operator (zo), a sports physician employed in a dedicated musculoskeletal ultrasound unit, with 15 years of ultrasound experience, including more than 10 000 shoulder examinations. the patients were examined using a siemens sonoline elegra 7.5 mhz linear multi-frequency probe manufactured in germany. both the symptomatic and asymptomatic tears were confirmed on ultrasound. the rotator cuff was examined with the arm in the neutral and adduction-internal rotation in the longitudinal (long) and transverse (trv) planes. the appearance of the rotator cuff, subacromial-subdeltoid (sasd) bursa and long head of the biceps were documented. the antero-posterior (ap) dimension of the fat between the supraspinatus and trapezius muscles and the supraspinatus muscle was measured at the level of the suprascapular neurovascular bundle medial to the acromion. the maximum width and length of the tear was recorded with the arm in the adduction-internal rotation. the majority of tears in this study were full-thickness tears involving the supraspinatus muscle. an entity called ‘tear progression or creeping tears’ involves smaller tears. there is little published on the natural history of small rotator cuff tears, and the answer to whether small tears progress to massive tears and the rate at which they might do so has yet to be fully established. many patients with symptomatic rotator cuff tears are shown to have an asymptomatic tear on the contralateral side. only some of these will become symptomatic and fewer will progress in size. in a 5-year follow-up study yamaguchi and colleagues 19 showed that half of 45 asymptomatic tears studied became symptomatic on follow up, but less than half of the 23 patients re-examined using ultrasound showed tear progression. full-thickness rotator cuff tears were diagnosed using the following criteria. 18 major criteria: any one of the following: (i) focal hypoechoic defect (fig. 1); (ii) changes in cuff contour; (iii) absent cuff/naked tuberosity sign (fig. 2); and (iv) communication between sasd bursa and glenohumeral joint. minor criteria: any one of the following: (i) thickened sasd bursa (fig. 3); (ii) sasd bursa fluid is a red flag for rotator cuff tear (fig. 4); and (iii) bone changes. normally the fat between the supraspinatus and trapezius muscles is thin or barely seen. the normal supraspinatus muscle has a hypoechoic appearance caused by hypoechoic muscle bundles, separated by thin hyperechoic lines, the fibroadipose septae or perimysium. 17 when there is a complete tear of the supraspinatus, there is retraction and atrophy of the muscle, with a decrease in ap dimension. the muscle becomes hyperechoic caused by a decrease in hypoechoic muscle bundles and an increase in hyperechoic fibroadipose septae and fat. 11 as the tear befig. 1. full-thickness tear shown by the hypoechoic defect. a b pg23-28.indd 24 4/4/07 9:51:03 am comes chronic the supraspinatus muscle atrophies and the ap dimension decreases, the space left is filled with fat, with an increase in the ap dimension of the fat between the supraspinatus and trapezius muscles (fig. 5). these changes are readily appreciated on magnetic resonance imaging (mri) with a loss of muscle bulk and increased signal on t1-weighted imaging reflecting atrophy. a number of studies have been directed at the assessment of supraspinatus muscle atrophy using ultrasound, but firm guidelines have yet to be established. 11 in this study we considered a tear acute when the supraspinatus muscle had a normal hypoechoic appearance and the fat between the supraspinatus muscle was thin or barely seen. we considered a tear chronic when there was atrophy of the muscle of the supraspinatus and an increase of the fat between the supraspinatus muscle and trapezius. confirmation of rotator cuff impingement is an important part of the routine ultrasound examination of the painful shoulder. impingement refers to shoulder pain during abduction or abduction-flexion-internal rotation of the shoulder. the syndrome results from impingement of the soft tissues between the humerus, ac joint, acromion, and coraco-acromial ligament, and in the advanced stages causes rotator cuff tears and rotator cuff arthropathy. stages of impingement on ultrasound according to neer are as follows: 17 • stage i oedema and haemorrhage in the bursa and rotator cuff. • stage ii fibrosis and thickening of the bursa and partial rupture of the rotator cuff. • stage iii complete rupture of the rotator cuff. the principal role of ultrasound is to determine what stage of impingement the disease has progressed to; this added information can be very helpful for treatment planning. 11 a fig. 4. longitudinal image of fluid in sasd bursa. fig. 5. transverse images of the trapezius and supraspinatus muscles medial to the acromion. in (a) there is a chronic full-thickness tear of the supraspinatus with atrophy and fatty infiltration of the muscle and increased dimension of the fat between the trapezius and supraspinatus, (b) normal supraspinatus muscle. fig. 3. longitudinal image of thickened sasd bursa. fig. 2. transverse images of absent rotator cuff or naked tuberosity sign (a) and normal rotator cuff (b). deltoid sajsm vol 19 no. 1 2007 25 a b pg23-28.indd 25 4/4/07 9:51:12 am 26 sajsm vol 19 no. 1 2007 dynamic examination during active shoulder motion is also routinely performed to document if there is impingement. 2 all the results were recorded on previously prepared computerised forms and photos were taken for documentation. a paired comparison using the wilcoxon’s non-parametric test was used, because distributions of differences were not normal. the chi-squared test was used to determine significant differences between the asymptomatic and symptomatic shoulders with regard to the number of ultrasound findings. results twenty-seven patients (54%) had tears in their asymptomatic shoulders (i.e. these patients had bilateral tears). these results are higher than universally excepted. table i documents the tears according to age. the mean standard deviation, and minimum and maximum width and length of the tears are given in table ii. according to the wilcoxon’s rank sum test the symptomatic tears were significantly larger in width (p = 0.0113) and length (p = 0.0487). the ap dimension of the supraspinatus muscle and the ap dimension of the fat between the supraspinatus and trapezius muscles were measured (fig. 6). the wilcoxon’s rank sum test for paired data indicated that the symptomatic tears appeared more chronic, with significant atrophy of the muscle of the supraspinatus (p = 0.0001) and significant increased thickness of the fat between the muscles of the supraspinatus and trapezius (p = 0.0002). table iii gives the mean, standard deviation minimum and maximum in millimetres for the symptomatic and asymptomatic shoulders. the presence of other findings on ultrasound were recorded in the symptomatic and asymptomatic shoulders, the appearance of the biceps tendon, sasd bursa, the presence of a glenohumeral joint effusion, signs of impingement according to neer’s classification and size of the tears. 17 when there is a full-thickness rotator cuff tear present, the space between the glenohumeral joint and the sasd bursa is continuous, thus it is impossible to distinguish between sasd bursa effusion and a glenohumeral joint effusion. in patients with full thickness tears, we reported the fluid as glenohumeral when it was located mainly in the biceps sheath and the posterior glenohumeral joint recess, but not in the bursa. if the biceps tendon appeared thickened/ thinned with a hypoechoic heterogenic image, it was documented as a biceps tendinopathy (fig. 7). the normal sasd bursa is not thicker than the humeral head cartilage and does not contain fluid. if the bursa contained fluid (fig. 4) and appeared thickened (fig. 3) it was table i. percentage with tears in asymptomatic shoulder for each age group age group (years) percentage 40 59 (20 patients) 35 60 69 (13 patients) 54 70 83 (17 patients) 77 fig. 6. chronic supraspinatus tear with atrophy and fatty infiltration of the muscle and increased dimension of the fat between the supraspinatus and trapezius muscles. fig. 7. transverse image of normal biceps (a) and biceps tendinopathy (b). pg23-28.indd 26 4/4/07 9:51:16 am documented as a sasd bursitis. 18 the incidence of these findings in the asymptomatic and symptomatic shoulders is recorded in table iv. the estimated probability of the presence of these findings in the symptomatic shoulder is given in table v. the highest probability is associated with glenohumeral joint effusion (0.686). relative to the other findings, a glenohumeral joint effusion is the strongest indicator of pain. the second strongest indicator of pain is biceps tendinopathy (0.649). the weakest indicator is signs of impingement (0.140). it is also necessary to consider the incidence of these findings being an indicator of pain. the question might be raised whether there are a different number of findings present in the symptomatic and asymptomatic shoulders. table vi gives the number of shoulders on the symptomatic and asymptomatic sides with 0, 1 and up to 5 other findings present. table ii. size of tears in symptomatic and asymptomatic shoulders size of tears (mm) symptomatic shoulder (n = 27) asymptomatic shoulder (n = 27) wilcoxon’s p-value mean width 16.70 3.44 0.0113 standard deviation of width 9.59 11.30 minimum width 2.00 2.00 maximum width 40.00 40.00 mean length 18.19 15.33 0.0487 standard deviation of length 10.70 10.24 minimum length 2.00 3.00 maximum length 36.00 32.00 table iii. ap dimensions of the supraspinatus muscle (n = 49) and fat (n = 50) between the supraspinatus and trapezius muscles ap dimensions (mm) symptomatic shoulder asymptomatic shoulder wilcoxon’s p -value mean supraspinatus 18.90 20.47 0.0001 standard deviation of supraspinatus 4.36 4.58 minimum supraspinatus 6.00 8.00 maximum supraspinatus 27.00 29.00 mean fat 6.92 5.32 0.0002 standard deviation of fat 2.57 2.49 minimum fat 0 0 maximum fat 14.00 11.00 table iv. number of other imaging findings (n = 50) imaging findings both shoulders only symptomatic shoulder only asymptomatic shoulder not present biceps tendinopathy 13 24 2 11 sasd bursitis 38 11 1 0 glenohumeral joint effusion 11 24 0 15 impingement 43 7 0 0 tear present 27 23 0 0 table v. estimated probability of other findings present only in symptomatic shoulder imaging findings probability glenohumeral joint effusion 0.686 biceps tendinopathy 0.649 grade of tear 0.460 sasd bursitis 0.224 signs of impingement 0.140 table vi. number of other findings per shoulder findings 0 1 2 3 4 5 symptomatic 0 0 0 7 15 28 asymptomatic 5 1 17 15 5 7 sajsm vol 19 no. 1 2007 27 pg23-28.indd 27 4/4/07 9:51:16 am 28 sajsm vol 19 no. 1 2007 a chi-squared test of independence indicated that there is a significant difference (0 = 0.0001) between the asymptomatic and symptomatic shoulders with regard to the number of other ultrasound findings present. it can be seen that a high percentage of symptomatic shoulders have more than 3 other findings, while a relatively high percentage of asymptomatic shoulders have 3 or less findings. discussion the aim of the study was to examine the integrity of the asymptomatic rotator cuff in patients with a confirmed symptomatic rotator cuff tear on ultrasound in the opposite shoulder, and to identify any other relevant ultrasound findings that would distinguish symptomatic from asymptomatic tears. the high incidence of asymptomatic tears in the study group indicate, as other authors have found, that rotator cuff tears can be regarded as a natural correlate of aging and that bilateral tears are common. 11,12 from table iv one can deduce that with all 5 other findings present it is highly likely that the shoulder will be painful. good indicators of pain were the presence of a glenohumeral joint effusion and biceps tendinopathy, which could be indicators of glenohumeral dysfunction. although the asymptomatic shoulders have a high prevalence of tears, we also found that the tears in the symptomatic shoulders were significantly larger and more chronic. the presence of a tear does not indicate a source of pain; it seems that pain might be caused by the size of the tear and not necessarily the mere existence of a tear. but one must realise, as shown in table vi, that the asymptomatic shoulder may have similar or more ultrasound findings. therefore the decision to operate based on size of tear is not yet clear. our study indicates that larger tears may benefit from early surgery before becoming chronic and causing glenohumeral dysfunction. references 1. bouffard ja, lee s, dhanju j. ultrasonography of the shoulder. semin ultrasound ct mri 2000; 21:164-91. 2. breckon c, davidson d. understanding the shoulder complex and comprehensive management of common conditions. johannesburg, centre for sports medicine and orthopaedics, 2006. 3. burkhart ss. fluoroscopic comparison of kinematic patterns in massive rotator cuff tears. a suspension bridge model. clin orthop 1992; 284:14452. 4. calvert pt, packer np, stoker dj, bayley ji, kessel l. arthrography of the shoulder after operative repair of the torn rotator cuff. j bone joint surg br 1986; 68(1): 147-50. 5. cardinal e. dynamic ultrasound of musculoskeletal pathology.16th annual conference of the musculoskeletal ultrasound society, seoul, korea, 27 may 1 june 2006. 6. de palma af. surgery of the shoulder. 3rd ed. philadelphia: jb lippincott, 1983. 7. hawkins r. rotator cuff tears. presented at the orthopaedic symposium on rotator cuff tears. antwerp, belgium, 24-25 february 1989: 25. 8. iannotti jp. the rotator cuff: current concepts and complex problems. rosemont ill.: american academy of orthopaedic surgeons, 1998: 1-12. 9. jacobson ja. ultrasound in sports medicine. radiol clin north am 2002; 40:364-70. 10. marcelis s, jager t. musculoskeletal ultrasound. aloka clinical library series i, 2006. 11. mcnally eg. practical musculoskeletal ultrasound. amsterdam: elsevier, 2005: 44,48,50,54. 12. milgram c, schaffler m, gilbert s, van holsbeeck mt. rotator cuff changes in asymptomatic adults. j bone joint surg br 1995; 77:296-8. 13. rockwood ca, burkhead wz. management of patients with massive rotator cuff defects by acromioplasty and rotator cuff debridement. orthop trans 1988; 12:190-1. 14. sher js, uribe jw, posada a, et al. abnormal findings on magnetic resonance images of asymptomatic shoulders. j bone joint surg am 1995; 77:10-4. 15. teefey sa, william md, middelton md. shoulder sonography, state of the art. radiol clin north am 1999; 37:772-3. 16. van holsbeeck mt, graig jg, booffard ja. radiological society of north america special course in ultrasound, 1996: 117-23. 17. van holsbeeck mt, introcaso jh. musculoskeletal ultrasound. 2nd ed. philadelphia: mosby, 2001: 27,465, 477-87. 18. van holsbeeck mt, kolowich pa. anatomy, physical examination and ultrasound of the shoulder. 16th annual conference of the musculoskeletal ultrasound society, seoul, korea, 27 may 1 june 2006. 19. yamaguchi k, tetro am, blam o, evanoff ba, teefey sa, middleton wd. natural history of asymptomatic rotator cuff tears: a longitudinal analysis of asymptomatic tears detected sonographically. j shoulder elbow surg 2001; 10:199-203. pg23-28.indd 28 4/4/07 9:51:17 am 60 sajsm vol 19 no. 2 2007 introduction anterior knee pain is a common musculoskeletal disorder found in children, adolescents and adults. it frequently interferes with sporting and everyday activities, and as a result a large number of children and adolescents may be forced to limit their physical activity or perform suboptimally on the sports field. the condition may affect up to 25% of all sportsmen and women. 8 cessation of physical activity is detrimental to the developing child as it negatively affects physical development, general fitness, body composition, the development of motor skills, and psychosocial development. 6,20 it may also lead to the adoption of lifelong sedentary lifestyle habits which poses a health risk in later life. there is a lack of consensus in the literature, especially in earlier studies, as to the exact definition of the term anterior knee pain. the terms anterior knee pain, patellofemoral pain, chondromalacia patella and patellofemoral arthralgia were used interchangeably in the past. a clinical examination alone may not necessarily identify the source of pain, and costly, invasive procedures are not indicated for most patients. as a result, these nonspecific terms listed above have been used to describe the symptoms of this common clinical condition. 5 anterior knee pain is a symptom complex characterised by pain in the vicinity of the patella, which is worsened by sitting, squatting, ascending or descending stairs and vigorous physical activity. 2,4,11,15,18,26,27 the pain can usually be related to the anterior structures of the knee, but is often poorly localised. 1,18,26,27,29 the condition is often self-limiting, but can take up to 2 years to resolve. 20 patellofemoral pain syndrome is a common cause of anterior knee pain, and is said to affect 20% of the general population, and an even greater percentage of the sporting population. 10,12 a number of studies have reported that the condition accounts for between 20% and 40% of all knee conditions presenting at sports injury clinics. 11,14,15,25 in this study, the term ‘anterior knee pain’ was used to describe the symptom complex characterised by pain in the anterior region of the knee during activity and prolonged sitting in the absence of an identifiable pathological condition. the exact aetiology is unknown but a number of predisposing factors have been suggested as possible causes. 11,32,33 these include overuse, muscle imbalance, muscle tightness, trauma, overweight, genetic predisposition, valgus or varus knee, external tibial torsion, increased qoriginal research article incidence of non-traumatic anterior knee pain among 11 17-year-olds abstract objective. to investigate the incidence of anterior knee pain, as well as the effect of sport participation, age of onset and gender differences on the condition. design. questionnaires (n = 2 414), each containing 20 questions, were distributed to 10 17-year-old learners at 8 primary and 5 high schools in the empangeni/richards bay area. the return rate was 76%. results. twenty-seven per cent of the respondents reported anterior knee pain. of these, 21% experienced pain in the left knee only, 34% in the right knee only, and 45% in both knees. furthermore, 31% had visited a medical doctor because of the knee pain, 82% reported that the pain interfered with their sport participation, and 37% had visited a physiotherapist or biokineticist, of whom 43% reported that the intervention they received was successful. previously 37% of the subjects had taken medication for the condition. the highest incidence of anterior knee pain was reported for 12 and 13-year-old girls and 14 15-year-old boys, which correlates with the period of the adolescent growth spurt. the incidence of anterior knee pain was higher amongst those who participated in sport more than 3 days per week and lower amongst those who participated less than 3 days per week or not at all. conclusions. anterior knee pain is common amongst children between the ages of 10 and 17 years, with a peak during adolescence, especially among girls. participation in physical activity increases the likelihood of anterior knee pain. correspondence: m f coetsee department of human movement science university of zululand private bag x1001 kwadlangezwa 3886 tel: 035-902 6648 fax: 035-772 6639 e-mail: mcoetsee@pan.uzulu.ac.za j phillips (bsc hons biokinetics) m f coetsee (phd) department of human movement science, university of zululand pg60-64.indd 60 7/5/07 10:39:01 am sajsm vol 19 no. 2 2007 61 angle, abnormal mechanics of the foot and ankle, especially pronation, and generalised ligament laxity. 2,7,15,16,19, 21,22,25,32,34 it has also been suggested that growth-related factors unique to the adolescent population may be important contributing factors in the epidemiology of anterior knee pain. 13,30,31 ruffin and kiningham 26 reported that of 16 748 patients presenting to family doctors with musculoskeletal complaints as a result of a variety of sports participation, 11.3% had anterior knee pain. the condition may account for 5 10% of all injuries seen at sports injury clinics. 15,33 while these studies refer to the general and sporting population, a study by fairbank et al. 7 found that 136 of 446 randomly selected pupils from a school of 1 850 learners had suffered knee pain in the previous year. at 31%, this is a fairly high incidence. this figure is supported by harrison et al. 10 who reported the prevalence in the adolescent population to be 30%. another study 8 on school children aged between 10 and 18 years found that as many as 45% of the cross-section of adolescents had anterior knee pain on physical examination. the authors acknowledge that it is likely that adolescents with the condition would have been more likely to volunteer for the study than those without knee pain. 8 the aim of the present study was to investigate the incidence of anterior knee pain, the effect of sport participation, age at onset of the condition, gender differences and other factors that could influence the condition among 11 17-yearold males and females. methods a questionnaire consisting of 20 questions, printed in english and afrikaans was distributed to learners at 8 primary and 5 high schools in the empangeni/richards bay area with permission of the headmaster of each school. all the schools were multi-racial and no distinction was made between race groups. girls and boys between the ages of 10 and 17 years were eligible for the study. pupils could complete the questionnaire under the guidance of a researcher or at home with the assistance of their parents, but in most cases it was done in the presence of the researcher in class, thereby reducing the risk of bias. the protocol for the study was approved by the ethics committee of the university of zululand. the questionnaire was designed based on information gleaned from a number of similar studies. 8,10,35 the majority of questions required the respondent to choose from amongst a number of answers. a few questions allowed space for further explanation. in order to investigate the incidence of anterior knee pain the subjects were divided into 2 categories, i.e. those with positive anterior knee pain and those who did not have any knee pain. to be classified with positive anterior knee pain the subject had to have met the following criteria while completing the questionnaire: s/he must have indicated the location of the pain on the anterior surface of the knee on the diagram, listed pain in excess of 1 month’s duration, indicated the severity of pain as moderate to severe, and indicated that the pain had interfered with sport participation. results a total of 2 414 questionnaires were handed out, of which 1 865 were returned, with 33 spoilt or the respondents being younger than 10 years of age. this gave a return rate of 76%. for the purposes of this article 475 subjects were excluded from the study as they had reported previous incidences of traumatic knee injury, and a further 147 were excluded as their answers concerning knee pain were inconclusive. both these groups of subjects could have fallen into either of the categories used for this article, and their exclusion was therefore necessary. table i indicates that 27% of the sample group had anterior knee pain. of the subjects who reported anterior knee pain, 21% experienced it in the left knee only, 34% in the right knee only, and 45% in both knees. thirty-one per cent of subjects had visited a medical doctor because of the knee pain, 82% reported that the pain interfered with their sport participation, and 37% had visited a physiotherapist or biokineticist, of whom 43% reported that the treatment they received was successful. thirty-seven per cent of the subjects had taken medication for the anterior knee pain. the average duration of pain experienced prior to completion of the questionnaire was 5 months. table ii indicates the activities and conditions that subjects reported as aggravating their anterior knee pain. running was the activity that most affected the condition, followed by jumping and kneeling. in the present study the girls displayed a slightly lower average incidence (26%) of anterior knee pain than the boys (30%) for the age group 10 17 years. however, when the data for only 12 15 years of age was considered the girls displayed a higher incidence of anterior knee pain than the boys (fig. 1). at age 10 11 and especially 16 17 the boys showed a higher incidence of anterior knee pain than the girls. table i. number and percentage of subjects per category and per gender (n = 1 210) number of percentage of male female category subjects total subjects n % n % positive akp 331 27 142 30 189 26 no knee pain 879 73 338 70 541 74 akp = anterior knee pain. pg60-64.indd 61 7/5/07 10:39:01 am 62 sajsm vol 19 no. 2 2007 the highest incidence for girls was found at 13 years of age, while that for the boys was at 14 years of age. while the girls showed a slight peak in the incidence of anterior knee pain around 12 13 years, it was less defined for the boys. however, a chi-square test did not show a significant (p > 0.05) dependence between age and pain percentages for males as well as for females. a mann-whitney test for independent samples (2-tailed) showed no significant (p > 0.05) difference between genders. fig. 2 shows the incidence of anterior knee pain amongst the respondents who reported sport participation of different durations. the chi-square test showed a dependency (p = 0.0000008) between frequency of participation and anterior knee pain. a binomial test for percentages to determine whether change in percentage of anterior knee pain was significant as frequency of participation increased (2-sided test at 5%) showed a significant increase between 0 v. 1 3 times/week (p = 0.00001) and 1 3 v. 3 5 times/week (p = 0.00726). the increases between 3 5 v. 5 7 times/week and 5 7 v. > 7 times/week were non-significant (p > 0.05). table iii shows the activity profile of respondents according to different sporting codes. girls with anterior knee pain reported a slightly higher participation in all sporting codes compared with girls with no knee pain. athletics and swimming were the codes most commonly associated with the condition, followed closely by netball. all sports, except hockey and tennis, resulted in a higher incidence of anterior knee pain amongst the boys. the sports with the highest difference amongst boys were rugby, soccer, athletics and swimming. however, a chi-square test showed no significant (p > 0.05) dependence between sport type and anterior knee pain percentages for males as well as for females. a mannwhitney test for independent samples (2-tailed) showed no significant (p > 0.05) difference between genders. discussion the 27% incidence of anterior knee pain among the sample group (table i) is comparable to the 20 40% reported in the literature for this age group. 11,14,15,25 while little research evidence is presented in the literature, the occurrence of anterior knee pain has been reported as being higher amongst girls. 17,18,23,24 goodfellow et al. 9 reported that the incidence of knee pain in girls compared with boys was 3:2. contrary to the observations of those authors the present study did not show a significant (p > 0.05) difference in incidence of anterior knee pain between girls and boys. the girls displayed a slightly lower average incidence (26%) of anterior knee pain than the boys (30%) for the age group 10 17 years. among the age group 12 15 years the girls displayed a higher peak than the boys (fig. 1). the graph for the boys was much flatter, thereby showing a higher incidence of anterior knee pain during the years 10 11 and especially 16 17 than the girls. however, none of these differences was significant (p > 0.05). the highest incidence of anterior knee pain reported for 12 13-year-old girls and 14 15-year-old boys correlates with the period of the adolescent growth spurt. the growth spurt begins at roughly 10.5 11 years in girls, and 12.5 13 years in boys, and lasts for approximately 2 years. however, there is wide variation, and the spurt may occur anywhere between 10.5 and 16 years of age. 28 there does not appear to be consensus on any demonstrable factor causing the peak in anterior knee pain during adolescence. possible suggestions include hormonal changes and changes directly related to the sudden increase in height. during the spurt, linear growth occurs in the bones first, followed by growth in the soft fig. 1. percentage of subjects (n = 1 210), per age group and gender, displaying anterior knee pain at the time of completing the questionnaire. fig. 2. influence of sport participation on incidence of anterior knee pain (akp). table ii. activities and conditions reported by subjects to aggravate the anterior knee pain (n = 331) activity % of subjects affected running 72 jumping 31 kneeling 31 walking 28 walking up stairs 20 cold weather 19 walking down stairs 14 standing 12 sitting 7 pg60-64.indd 62 7/5/07 10:39:04 am sajsm vol 19 no. 2 2007 63 tissues. boys experience reduced flexibility over this period while girls have increased flexibility. 20 it has been proposed that girls are at a higher risk of joint pain and injury at this stage due to this increased flexibility, and possible ligament laxity or muscle weakness. 3 fig. 2 demonstrates that sport participation up to 5 times per week significantly (p > 0.05) increased the incidence of anterior knee pain. participation of more than 5 times per week did not further increase the incidence of anterior knee pain. this seems to support the finding that a higher percentage of subjects with anterior knee pain take part in the different sporting codes, as shown in table iii, than subjects without knee pain even though these differences were nonsignificant (p > 0.05). thus it can be concluded that regular sport participation does increase the risk for anterior knee pain. this finding is supported by the literature where it is stated that the condition is more common among physically active individuals, especially adolescent girls. 7,15,27 during the adolescent phase the knee structure becomes compromised which predisposes it to injury. this, combined with the added stress during sport participation, could account for the higher incidence of anterior knee pain. conclusion anterior knee pain is common amongst 10 17-year-olds, with a peak during the ages 12 15 years for girls, while the boys showed a more even distribution. participation in regular physical activity increases the development of anterior knee pain. cessation of exercise, on the other hand, should not be the preferred course of action as it could negatively influence the development and health status of the individual. emphasis should rather be on improving non-invasive rehabilitation techniques. preliminary results show that physiotherapy and biokinetic intervention has a positive effect and it is recommended that this avenue be explored further. acknowledgements the university of zululand supported this study financially. references 1. carson wg, james sl, larson rl, singer km, winternitz ww. patellofemoral disorders: physical and radiographic evaluation. part 1: physical examination. clinical orthopaedics and related research 1984; 185: 165-77. 2. cesarelli m, bifulco p, bracale m. quadriceps muscle activation in anterior knee pain during isokinetic exercise. med eng phys 1999; 21: 469-78. 3. chandy ta, grana wa. secondary school athletic injury in boys and girls: a three year comparison. physician and sports medicine 1985; 13: 106-11. 4. clark di., downing n, mitchell j, coulson l, syzpryt ep, doherty m. physiotherapy for anterior knee pain: a randomised controlled trial. ann rheum dis 2000; 59: 700-4. 5. crossley k, bennell k, green s, cowan s, mcconnell j. physical therapy for patellofemoral pain: a randomized, double-blinded, placebo-controlled trial. am j sports med 2002; 30: 857-65. 6. difiori jp. overuse injuries in children and adolescents. physician and sports medicine 1999; 27(1): 75-89. 7. fairbank jc, pynsent pb, van poortvliet ja, phillips h. mechanical factors in the incidence of knee pain in adolescents and young adults. j bone joint surg (br) 1984; 66: 685-93. 8. galanty hl, matthews c, hergenroeder ac. anterior knee pain in adolescents. clin j sport med 1994; 4: 176-81. 9. goodfellow j, hungerford ds, zindel m. patello-femoral joint mechanics and pathology: functional anatomy of the patello-femoral joint. j bone joint surg br 1976; 58: 287-99. 10. harrison e, quinney h, magee d, sheppard ms, mcquarrie a. analysis of outcome measures used in the study of patellofemoral pain syndrome. physiotherapy canada 1995; 47: 264-72. 11. heng rc, haw cs. patello-femoral pain syndrome: diagnosis and management from an anatomical and biomechanical perspective. current orthopaedics 1996; 10: 256-66. 12. hilyard a. recent advances in the management of patellofemoral pain: the mcconnell programme. physiotherapy 1990; 76: 559-65. 13. holmes sw, clancy wg. clinical classification of patellofemoral pain and dysfunction. journal of orthopaedic and sports physical therapy 1998; 28: 299-306. 14. johnson rp. anterior knee pain in adolescents and young adults. curr opin rheumatol 1997; 9: 159-64. table iii. participation profile (percentage) in specific sports for subjects displaying anterior knee pain (akp) and subjects with no knee pain males females no knee pain (n =338) akp (n = 142) difference no knee pain (n = 541) akp (n = 189) difference athletics 33 44 +11 26 41 +15 cricket 44 47 +3 2 6 +4 dancing 2 3 +1 20 22 +2 gymnastics 1 1 0 2 5 +3 hockey 20 17 -3 37 43 +6 netball 0 0 0 25 34 +9 rugby 40 54 +14 0 2 +2 soccer 46 59 +13 4 6 +2 squash 5 5 0 3 5 +2 swimming 25 39 +14 28 40 +12 tennis 12 8 -4 10 14 +4 other 11 16 +5 6 10 +4 pg60-64.indd 63 7/5/07 10:39:04 am 64 sajsm vol 19 no. 2 2007 15. kannus p, niittymaki s. which factors predict outcome in non-operative treatment of patellofemoral pain syndrome? a prospective follow-up study. med sci sports exerc 1994; 26: 289-96. 16. karlsson j, thomee r, sward l. eleven year follow-up of patello-femoral pain syndrome. clin j sport med 1996; 6: 22-6. 17. lichota dk. anterior knee pain: symptom or syndrome? curr womens health rep 2003; 3: 81-6. 18. nimon g, murray d, sandow m, goodfellow j. natural history of anterior knee pain: a 14to 20-year follow-up of non-operative management. j pediatr orthop 1998; 18(1): 118-22. 19. o’ neill db, michell lj, warner jp. patellofemoral stress: a prospective analysis of exercise treatment in adolescents and adults. am j sports med 1992; 20: 151-6. 20. patel dr, nelson tl. sports injuries in adolescents. med clin north am 2000; 84: 983-1005. 21. pollock d. clinical examination of the patello-femoral joint. south african orthopaedic journal 2004; 3(4): 8-10. 22. post wr. patellofemoral pain: let the physical exam define the treatment. physician and sports medicine 1998; 26(1): 68-79. 23. powers cm. rehabilitation of patellofemoral joint disorders: a critical review. journal of orthopaedic and sports physical therapy 1998; 28: 34554. 24. price a, jones j. chronic traumatic anterior knee pain. injury 2000; 31: 373-8. 25. roush mb, sevier tl, wilson jk, et al. anterior knee pain: a clinical comparison of rehabilitation methods. clin j sport med 2000; 10(1): 22-8. 26. ruffin mt, kiningham rb. anterior knee pain: the challenge of patellofemoral syndrome. am fam physician 1993; 47(1): 185-94. 27. sandow mj, goodfellow jw. natural history of anterior knee pain in adolescents. j bone joint surg br 1985; 67(1): 36-8. 28. sinclair d. human growth after birth. 5th ed. oxford: oxford university press, 1989. 29. souza dr, gross mt. comparison of vastus medialis obliquus: vastus lateralis muscle integrated electromyographic ratios between healthy subjects and patients with patellofemoral pain. phys ther 1991; 71: 310-20. 30. stathopulu e, baildam e. anterior knee pain: a long-term follow-up. rheumatology 2003; 42: 380-2. 31. teitz cc. the female athlete. j am acad orthop surg 1997; 5: 89-94. 32. thomee r, augustsson j, karlsson j. patellofemoral pain syndrome: a review of current issues. sports med 1999; 28: 245-62. 33. wilson t. anterior knee pain: a new technique for examination and treatment. physiotherapy 1990; 76: 371-6. 34. woodall w, welsh j. a biomechanical basis for rehabilitation programs involving the patellofemoral joint. journal of orthopaedic and sports physical therapy 1990; 11: 535-42. 35. reider b, marshall jl, warren rf. clinical characteristics of patellar disorders in young athletes. am j sports med 1981; 9: 270-6. clinical sports medicine medical management and rehabilitation, text with cd-rom isbn 1416024433 / 9781416024439 ä 512 pages ä 336 illustrations saunders ä published september 2006 only a fraction of sports medicine injuries require surgery, but most sports references emphasize surgical management over medical management and rehabilitation. clinical sports medicine: medical management and rehabilitation is the only comprehensive sports medicine resource to focus on the medical management and rehabilitation of patients. written by some of the most prominent names in physical medicine & rehabilitation, this book fills a void by providing an outstanding sports medicine reference aimed at non-surgeons. the international contributors to this book present you with global best practices from world leaders in the field. the main focus lies on the practical information you need to implement the most effective non-surgical management and rehabilitation approaches for today's diverse patient population. pg60-64.indd 64 7/5/07 10:39:05 am sajsm vol 19 no. 5 2007 125 introduction following the 1995 rugby world cup, the game of rugby was introduced as a professional sport by the international rugby board (irb). rugby league had a large following and was tempting rugby union players with the promise of big salaries. the professionalism of rugby union was seen as the way to preserve the game and maintain the players. despite the rule changes accompanying the professionalism of rugby, there has been a subsequent increase in rugby injuries. 1,6 although this may not seem relevant for club players, the study of garraway et al. 6 revealed increases in injuries for both senior club (amateur) and professional rugby players from the 1993 1994 season (pre-professional) to the 1997 1998 season (professional). it would appear that there is now a greater emphasis placed on players’ speed, strength and endurance than before the professional era. 6 the stellenbosch rugby football club (hereafter referred to as srfc) is made up of five senior teams (including one women’s team), five junior teams (three under-20 and two under-19 teams), as well as 45 hostel teams and has more than 1 200 registered players. srfc also has a proud history of players who have proceeded to represent their province and country. in 1973 10 and 1974 1975, 12 research studies were conducted to investigate the nature and proportion of total injuries occurring during these seasons at srfc. in 2003, the university’s rugby injury database was developed to log and organise rugby injury data from srfc for further analysis. fellow researchers acknowledge a lack of a standardised definition of injury, which makes comparison between studies difficult. 1,3,6,7,9 however, regardless of the definition of injury used, the reported incidences of rugby injury remain among the highest in sport. 4 the major aim of this descriptive study was to compare the nature and proportion of total injuries occurring at srfc between the years 1973 1975 and 2003 2005. original research article nature and proportion of total injuries at the stellenbosch rugby football club: a comparison of the years 1973 1975 with 2003 2005 abstract objective. the purpose of this study was to compare the nature and proportion of total injuries occurring at stellenbosch rugby football club in stellenbosch, south africa, between the years 1973 1975 and 2003 2005. design. retrospective, descriptive study. main outcome measures. injured rugby players from the stellenbosch rugby football club from the different time periods were included in the study. results from the 1973 1975 time period were obtained from two previously published articles (roy, 1974; van heerden, 1976), while data from the 2003 2005 time period were available through the stellenbosch university rugby injury database. results. an increase in the proportion of head and facial injuries from 1973 1975 (21%) to 2003 2005 (42%) was found as well as a doubling in the proportion of concussions between the two time periods (12% 23%). there was an overall decrease in total injuries between the two time periods. conclusion. the findings highlight the high and increased proportion of head and facial injuries in the game of rugby at the stellenbosch rugby football club. this is a matter that should be further investigated. correspondence: michelle puren stellenbosch biokinetics centre private bag x1 matieland 7602 tel: (021) 808-4735 e-mail: mspuren@gmail.com m s puren (bsc sport science, hons b sport science (biokinetics)) j g barnard (ma, dphil sport science) department of sport science, stellenbosch university p l viviers (b med sc, hons b med sc, m med sc, mb chb, msc (sports med)) sport performance institute, stellenbosch university pg125-128.indd 125 1/11/08 12:30:35 pm 126 sajsm vol 19 no. 5 2007 methods subjects the subjects for this study came from the time periods of 1973, 1974 1975 and 2003 2005. the study population for both time periods comprised rugby hostel and senior or junior club players from srfc. injured srfc players were excluded from the study if the rugby player was injured during an away rugby match, if the injured rugby player did not play for a srfc team or if the injury was not rugby-related. in the 1973 rugby season 10 the injured srfc players were included if the rugby player was injured during a rugby match or practice and sought private medical treatment at the author’s medical practice. the injured srfc players for the 1974 1975 rugby season 12 were included if the rugby player was injured during a rugby match or practice resulting in medical treatment at stellenbosch university’s student health services. the injured srfc players of the 2003 2005 rugby season were included in the study if the rugby player was injured during a rugby match or practice resulting in medical treatment at the field. data collection injury definition: for the purposes of this study an injury was defined as an event which resulted in a player seeking medical assistance from the sports physician on duty at the rugby game or practice, regardless of whether the player stopped playing in the middle of the game or continued until the end before seeking the assistance. data source: the injury results of the 1973 and 1974 1975 srfc rugby seasons published in 1974 10 and 1976 12 respectively were compared with the injury findings of the 2003 2005 rugby seasons. the nature and proportion of total injuries were investigated for the two time periods. measurement tool: all the research studies (i.e. roy, 10 van heerden 12 and current) applied a questionnaire to collect the injury data. although these questionnaires were not exactly the same, each provided information about the player regarding the date of injury, age, height, weight, team, competition or practice, weather conditions, playing surface, shoe and stud type, position, phase of play, as well as site and type of injury sustained. the 1973 and 1974 1975 data were obtained from research published in 1974 10 and 1976, 12 respectively. however, the data from these studies were the authors’ published data and not the raw data. the 2003 2005 data were accessed through stellenbosch university’s rugby injury database. the method used for the injury data collection of the 2003 2005 season involved the presence of a sports physician and two postgraduate biokinetics students during all home matches and contact practice sessions for onsite acquisition of injury information. the sports physician was responsible for the diagnosis of the injury and the students on duty for the recording of the necessary information. data resource: the number of matches played in 1973 1975 and 2003 2005 were calculated from srfc annual reports for the respective years. injury categories: the category ‘head and face’ includes injuries of the head, face, nose, eye, ear, mouth and jaw but does not include injuries of the neck. the category ‘shoulder’ includes injuries of the shoulder and upper arm. the categories ‘knee’ and ‘ankle’ pertain to injuries of the knee and ankle respectively. these exact categories were used in the study of van heerden 12 when he compared his results with those of roy. 10 statistics the study is of a descriptive nature and it was decided to calculate the proportions of total injuries as percentages of the total injuries for the time periods of 2003 and 2004 2005, in keeping with those calculated by roy 10 and van heerden 12 for the time periods of 1973 and 1974 1975, respectively. results table i indicates the number of matches played, the number of teams involved and proportion of total injuries sustained, for the years 1973 1975 and 2003 2005, for both hostel and club teams. in 1973 1975 there were considerably more hostel matches played than during 2003 2005. in 2003 2005, more club matches were played than during 1973 1975. total match figures also include friendly matches. in total, more rugby matches were played during 1973 1975 (1 807 matches) than during 2003 2005 (1 389 matches). in 1973 1975 there were slightly more hostel teams and slightly fewer club teams than during 2003 2005. considerably more injuries were sustained during the period of 1973 1975 compared with the 2003 2005 – more than double the amount. fig. 1 shows the most frequently injured anatomical site for the years 1973, 1974 1975, 2003 and 2004 2005. in 2003 (41%) and 2004 2005 (42%) there was a doubling of the percentage of injuries for the category of head and face, table i. number of hostel and club matches played, teams and total injuries for each year matches/injuries 1973 1974 1975 total 2003 2004 2005 total hostel matches (teams) 498 (52) 567 (51) 469 (52) 1 534 280 (46) 290 (46) 217 (45) 787 club matches (teams) 123 (7) 74 (4) 76 (5) 273 226 (10) 210 (10) 166 (8) 602 total matches 621 641 545 1 807 506 500 383 1 389 total injuries 300 485 900 1 685 238 272 251 761 pg125-128.indd 126 1/11/08 12:30:35 pm sajsm vol 19 no. 5 2007 127 while the percentage remained constant for 1973 (21%) and 1974 1975 (21%). the other three frequently injured sites have remained relatively stable, with some minor changes. there was a slight increase in the percentage of shoulder injuries in 2003 and 2004 2005 (12% and 12%, respectively) when compared with the 10% and 9% of the 1973 and 1974 1975 findings. the percentage of ankle injuries decreased from 14% in 1973 to 11% in 1974 1975. in 2003 and 2004 2005 the incidence is similar at 11% and 11% respectively. slight fluctuations are evident with the knee injuries, which increased from 14% in 1973 to 17% in 1974 1975 while in 2003 they decreased from 16% to 14% in 2004 2005. fig. 2 depicts the breakdown of head and facial injuries into lacerations, concussions and other head and facial injuries for the time periods 1973 1975 and 2003 2005. lacerations increased from 51% in 1973 1975 to 61% in 2003 2005, and concussions doubled from 12% in 1973 1975 to 23% in 2003 2005. other head and facial injuries decreased from 37% in 1973 1975 to 16% in 2003 2005. discussion the descriptive nature of this study and the limited possibilities for statistical analysis of the data do not allow firm conclusions to be drawn from the results obtained. a few limitations were encountered in the collection, access and analysis of the data, yet despite these limitations, the study still provides some interesting information concerning the nature and proportion of total injuries occurring at srfc 30 years following the initial two studies. a total of 1 685 recorded injuries occurred between 1973 and 1975 compared with the total of 761 for 2003 2005. the difference in total matches, played between the two time periods, is 418 matches, with more matches being played between 1973 and 1975 (1 807) compared with 2003 2005 (1 389). almost two and a half times more injuries occurred during 1973 1975. this is probably also an underestimation of injuries, due to the inclusion criteria used. van heerden 12 also states that 35% of these injuries occurred in 1974 and 65% in 1975. according to the proportion of total injuries by anatomical site for the years 2003, 2004 and 2005, it is apparent that the head and face hold the highest percentage of injuries compared with the other anatomical sites, followed by the knee, shoulder, and then ankle. these specific categories were compared with the findings of roy 10 and van heerden. 12 it would appear that there has been a large increase in the proportion of head and facial injuries between the three decades. the percentages for 1973 1975 doubled to 2003 2005. there was a 10% increase in the proportion of lacerations obtained in head and facial injuries, while the proportion of concussions has doubled. on the topic of increased injuries since professionalism, garraway et al. 6 state: ‘…changes in the laws of rugby union in recent years have been designed to encourage more open play. this has probably resulted in more tackles involving a higher degree of momentum or a greater degree of force’. perhaps this accounts for the increase in the proportion of head and facial injuries observed. the other three sites (knee, ankle and shoulder) remained relatively stable with little fluctuations. the finding of head and face being the most commonly injured anatomical site is consistent with the studies of targett, 11 gabbett, 5 bathgate et al., 1 and best et al. 2 although the studies of gabbett 5 and best et al. 2 also included neck injuries in this category, this is not considered a problem. should neck injuries have been added to the head and facial injuries investigated in this study, it would have only made the percentage higher. it is possible that the slightly higher percentage of lacerations of the head and face, which was recorded during the 2003 2005 time period, was because of the increased strictness concerning injuries involving blood. it is also possible that the doubling of concussions that was observed is due to the stricter guidelines concerning a player who has become concussed, resulting in more accurate reporting of these injuries. under the current irb laws, concussed players are subject to a ‘mandatory 3-week stand-down period’ regardless of whether the concussion is considered mild or severe. 8 in contrast, in 1974, roy 10 stated: ‘there is at present no set rule as to who is responsible for ordering the removal of an injured player from the field… permitting  lacerations concussion other 0 25 50 75 1973-1975 2003-2005 p ro p o rt io n o f to ta l h ea d an d fa ci al in ju ri es fig. 2. proportion of lacerations, concussions and other head and facial injuries.  head/face knee ankle shoulder 0 10 20 30 40 50 1973 1974-5 2003 2004-5 most frequentlyinjuredanatomical site f re q u en cy % fig.1. most commonly injured anatomical site per year/ season. pg125-128.indd 127 1/11/08 12:30:38 pm 128 sajsm vol 19 no. 5 2007 a player with concussion to continue playing should not be tolerated.’ conclusion the three commonly injured sites of the knee, ankle and shoulder remained similar over the two time periods, 1973 1975 and 2003 2005, in contrast to the higher total injuries for 1973 1975 and increased proportion of head and facial injuries for 2003 2005. an increase in the proportion of these particular injuries took place over the last 30 years whereas the total number of injuries decreased. it is of concern to note that concussion injuries have doubled. could this be due to poor tackling technique or some other skill which is lacking, or is it merely due to an increase in the reporting thereof? in order to obtain a better understanding of the findings observed, it would be beneficial to undertake further studies in this regard. references 1. bathgate a, best jp, craig g, jamieson m. a prospective study of injuries to elite australian rugby union players. br j sports med 2002; 36: 265-9. 2. best jp, mcintosh as, savage tn. rugby world cup 2003 injury surveillance project. br j sports med 2005; 39: 812-17. 3. bird yn, waller ae, marshall sw, alsop jc, chalmers dj, gerrard df. the new zealand rugby injury and performance project: v. epidemiology of a season of rugby injury. br j sports med 1998; 32: 319-25. 4. brooks jh, fuller cw, kemp sp, reddin db. epidemiology of injuries in english professional rugby union: part i match injuries. br j sports med 2005; 39: 757-66. 5. gabbett tj. incidence, site and nature of injuries in amateur rugby league over three consecutive seasons. br j sports med 2000; 34: 98-103. 6. garraway wm, lee aj, hutton sj, russell eb, macleod da. impact of professionalism on injuries in rugby union. br j sports med 2000; 34: 348-51. 7. junge a, cheung k, edwards t, dvorak j. injuries in youth amateur soccer and rugby players – comparison of incidence and characteristics. br j sports med 2004; 38: 168-72. 8. marshall sw, spencer rj. concussion in rugby: the hidden epidemic. j athl train 2001; 36(3): 334-8. 9. mcmanus a. validation of an instrument for injury data collection in rugby union. br j sports med 2000; 34: 342-7. 10. roy sp. the nature and frequency of rugby injuries: a pilot study of 300 injuries at stellenbosch. s afr med j 1974; 48: 2321-7. 11. targett sgr. injuries in professional rugby union. clin j sport med 1998; 8: 280-5. 12. van heerden jj. ‘n ontleding van rugbybeserings. s afr med j 1976; 50: 1374-9. sports medicine, an issue of physical medicine and rehabilitation clinics by gregory a. strock, md; and ralph m. buschbacher, md, clinical associate professor and interim chair, department of physical medicine and rehabilitation, indiana university; indiana university medical center; residency program director, community hospitals of indiana, indianapolis, in, usa isbn 1416039287 ä hardback ä 240 pages saunders ä published october 2006 treating an elite athlete or a weekend player has its challenges � mainly to get them back in the game right away. this issue covers injuries and treatments for an assortment of sports: golf, running, triathalon, basketball and more. also included are two exciting chapters on sports psychology and performance enhancing drugs and chapters on altitude medicine and martial arts. pg125-128.indd 128 1/11/08 12:30:39 pm 94 sajsm vol 19 no. 3 2007 introduction carbohydrate (cho) ingestion and the maintenance of euglycaemic blood glucose concentration have long been known to improve performance during prolonged exercise (> 90 min duration) 12, 15, 22. however, it was not until the 1980s that the performance benefits of cho ingestion during prolonged exercise were finally resolved. it has been shown by many studies that cycling endurance performance is enhanced when cho is ingested during prolonged exercise. 4-9 there are two mechanisms that were originally proposed to explain these findings. the first suggests that there is a muscle glycogen-sparing effect. 1, 9,16 however, this mechanism has been refuted by a number of studies, including those of bosch et al., 2 coyle et al., 8 flynn et al. 13 and levine et al. 21 the second and more widely accepted mechanism is that cho feeding delays the onset of fatigue by maintaining blood glucose concentrations and thereby preventing hypoglycaemia, via a liver glycogen sparing effect. 2,3 the maximum rate of ingested cho oxidation that can be achieved during the later stages of prolonged exercise is approximately 1 g.minute -1 (for review see 19 ). hawley et al. 18 reported a similar upper limit to exogenous cho oxidation (1.1 ± 0.1 g.min -1 ) after 120 minutes of exercise, when glucose was infused to maintain euglycaemia. in the same study it was shown that under conditions of hyperglycaemia (~10 mmol.l -1 ), the plasma glucose oxidation increased to ~ 1.8 g.min -1 during the final 30 minutes of exercise. this is in agreement with the suggestion by coyle et al. 10 that oxidation rates of exogenous cho may be able to reach 2 g per minute under hyperglycaemic conditions. these studies, as well as the performance studies described previously, were all carried out at constant workloads (70-75% of v02max). typically, during competitive road cycling races the workload is not constant but varies, depending on the terrain, course profile, environmental conditions and the racing strategies of the cycling group. 24 it is also important to note that none of the studies on the oxidation rate during hyperglycaemia investigated the possible associated effects on cycling performance. hawley et al., 17 however, have suggested that hyperinsulinaemia associated with hyperglycaemia may have an adverse effect on endurance performance during the first 90 120 minutes of prolonged exhaustive exercise. thus, the aim of the current study was to investigate any possible ergogenic effect of maintained hyperglycaemia on performance during a 100 km cycling laboratory time trial (tt) that was designed to simulate the variable intensity of competitive road racing. original research article maintenance of hyperglycaemia does not improve performance in a 100 km cycling time trial abstract objectives. the aim of this study was to determine whether the elevated plasma glucose oxidation rate (~ 1.8 g.min -1 ) in the latter stages of prolonged exercise in subjects in which hyperglycaemia (± 10 mmol.l -1 ) is maintained via a glucose clamp, improves 100 km cycling time-trial (tt) performance. design. seven endurance-trained male cyclists (22±4 yrs) participated in this randomised crossover trial. on two occasions, separated by 7 10 days, subjects performed a self-paced tt in the laboratory. during one tt blood glucose was maintained at a euglycaemic concentration of ± 5 mmol.l -1 (ett) and during the other, at ±10 mmol.l -1 (htt). each tt was interspersed with 5 x 1 km high-intensity periods (hip) and 4 x 4 km hip, in an attempt to mimic the variable intensity of competitive road races. subjects were instructed to complete the tt in the ‘fastest time possible’, taking the 9 hip (21 km) into consideration. results. there were no significant differences between ett and htt in overall time (143:09±7:14 v. 142:23±7:16 min:s), mean power (275±39 v. 279±39 w) and heart rate (160±9 v. 158±11 beats.min -1 ). conclusion. time trial performance over 100 km is not improved by maintaining a hyperglycaemic (10 mmol.l -1 ) blood glucose concentration. correspondence: a n bosch uct/mrc research unit for exercise science and sports medicine department of human biology university of cape town po box 115 newlands 7725 tel: 021-650-4578 fax: 021-686-7530 e-mail: andrew.bosch@uct.ac.za andrew n bosch (phd) mark c kirkman (bsc (med)(hon) exercise science) uct/mrc research unit for exercise science and sports medicine, nelwands, cape town pg94-98.indd 94 10/3/07 3:30:42 pm sajsm vol 19 no. 3 2007 95 methods subjects seven endurance-trained male cyclists participated in the study, which was approved by the research ethics committee of the faculty of health sciences of the university of cape town. all cyclists were training between 200 and 400 km per week and had completed a 105 km road race in less than 3 hours. subject characteristics are shown in table i. prior to the start of the trial all subjects were informed of the purpose of the investigation, and since glucose was infused intravenously and blood samples were taken, the procedures and risks involved were explained to the subjects and their written informed consent was obtained. preliminary testing on their first visit to the laboratory, subjects were tested for predicted peak oxygen uptake (v02peak) and peak power output (ppo) on their own bicycles, which were mounted on a kingcycle ergometer (kingcycle ltd, high wycombe, uk). the bicycle is attached to the ergometry system by the front fork and supported under the bottom bracket by an adjustable pillar. the bottom bracket support is used to adjust the rolling resistance of the rear wheel on an air-braked flywheel and the system is calibrated as previously reported by palmer et al. 25 after a 5-10 min self-paced warm up, the test began at a workload of 200 w, which was increased by 20 w.min -1 until volitional exhaustion. during each incremental test to exhaustion, subjects were instructed to remain in a seated position. ppo was taken as the highest average power during any 60 s period of the test. the ergometry system software predicted v02peak from the ppo. on their second visit to the laboratory, subjects performed a familiarisation ride. this ride was a tt identical to that which would be ridden during the experimental trials (described below), except that there was no intervention of any sort. experimental trials each subject completed a single blinded randomised crossover design of two experimental tts separated by 7-10 days. tts were performed at the same time of the day under standard laboratory conditions (~22°c and 55% relative humidity). a large electric fan was used to cool the subjects during exercise. subjects were requested to perform the same type of training for the duration of the trial and to refrain from heavy physical exercise on the day before each trial. they were also instructed to follow their normal diet for the 3 days leading up to each tt. the food consumed prior to the first tt was repeated prior to the next. they were required to keep training diaries and dietary records to assess their compliance to these conditions. on the morning of each tt subjects reported to the laboratory between 07h00 and 08h00, 12-14 hours after an overnight fast. at this time their bicycle was mounted on the kingcycle ergometer and the system was calibrated as previously described. a flexible 20-gauge teflon cannula (jelco; johnson and johnson, halfway house, gauteng, sa) attached to a three-way stopcock was positioned in an antecubital vein of the right forearm. this cannula was used for the variablerate glucose (20% dextrose) infusion used to maintain blood glucose concentration at the predetermined value of either 5 mmol.l -1 (ett) or 10 mmol.l -1 (htt) for the duration of the tt. a flexible 18-gauge teflon cannula attached to a three-way stopcock was positioned in an antecubital vein of the left forearm for blood sampling during the tts. blood samples (~ 0.5 ml) were drawn at 5 min intervals to measure blood glucose concentrations, so that glucose infusion rates could be adjusted via the glucose clamp technique 11 and modified for use during exercise by the authors to maintain the desired blood glucose concentration. a pocket gluco-meter (accutrend; boehringer mannheim, mannheim, germany) was used to measure blood glucose concentration. the accuracy of the glucometer has previously been verified by comparison with a beckman glucose analyser (glucose analyser 2; beckman instruments, fullerton, ca). subjects were then connected to the infusion pump (accura tg 2000, trigate ltd., randburg, sa) used to infuse the 20% dextrose solution, mounted their bicycle and began a 5-10 min self-paced warm up. just prior to the completion of the warm up, an initial priming dose of glucose was infused to achieve the desired blood glucose concentration for that tt (i.e. 5 or 10 mmol.l -1 ). table i. subject characteristics subject age height mass vo2peak peak power p:w hrpeak (yr) (m) (kg) (ml·kg-1 min-1) output (w) (w kg-1) (beats min-1) 1 21 1.84 64.0 81.3 466 7.28 196 2 26 1.86 89.5 58.4 468 5.23 186 3 21 1.85 73.5 61.6 404 5.50 180 4 19 1.78 83.0 56.6 420 5.06 193 5 17 1.67 58.0 76.9 398 6.86 194 6 28 1.73 72.0 61.6 396 5.50 191 7 22 1.68 65.0 65.2 378 5.82 186 mean (sd) 22 (4) 1.77 (0.08) 72.1 (11.1) 65.9 (9.5) 419 (35) 5.89 (0.85) 189 (6) vo2peak = protected peak oxygen uptake; p:w = power to weight ratio; hrpeak = peak heart rate. pg94-98.indd 95 10/3/07 3:30:42 pm 96 sajsm vol 19 no. 3 2007 following the warm up, subjects began the tt. in an attempt to mimic the changes in intensity associated with most competitive cycling road races, the tt included a series of high-intensity periods (hip): 5 bouts of 1 km duration after 10, 32, 52, 72 and 99 km, as well as 4 bouts of 4 km hip after 20, 40, 60 and 80 km. this protocol has previously been shown to be a repeatable measurement of performance (within-cyclist coefficient of variation of 1.7%). 26 subjects were instructed to complete the tt in ‘the fastest possible time’, taking into consideration the hip that were included in the protocol. prior to the start of a hip, an investigator gave a distance count down and instructed the cyclist to complete the hip in the fastest possible time. a financial reward was offered to the subject who completed the entire trial and the hip combined in the fastest time. in addition, verbal encouragement was also given during hip in a further attempt to evoke a maximal effort. prior to and during the ride, subjects viewed a diagram of the ‘course profile’, which graphically illustrated where each of the hip occurred. instantaneous power output was recorded at 500 m intervals during hip to provide an estimate of average power output. throughout each trial, power output, speed and elapsed time were monitored continuously and stored on computer. heart rate (hr) was recorded using a polar sporttester hr monitor (polar electro, kempele, finland). the only feedback the subjects received during the tt was elapsed distance and hr. during each tt, subjects were permitted to ingest water ad libitum. statistical analyses all results are presented as means ± sd. statistical significance (p < 0.05) of between group differences was assessed by a two-way analysis of variance (anova) with repeated measures over time (statistica for windows, version 6, statsoft, tulsa, ok, usa), followed by a tukey’s honest significant difference post-hoc test. results training and dietary diaries collected on the morning of each trial confirmed that each subject had followed a similar pretrial routine for both trials. none of the subjects participated in high-intensity or long-duration exercise on the day before any of the trials. mean blood glucose concentrations maintained during the trials by the glucose clamp were 4.9±0.2 mmol.l -1 and 10.1±0.3 mmol.l -1 for ett and htt, respectively. the mean time, power output and heart rate for ett and htt were similar (table ii). there was also no significant time by group interaction effects between the trials with regards to time taken or mean power for the hip (1 and 4 km) over the course of each tt. the subjects became fatigued during the trial as the fourth l km hip for both trials was significantly slower (p=0.016) compared with the first (fig. 1a) and had a significantly lower mean power (p=0.004) compared with the first and the last hip (p=0.02) (fig. 1b). the mean power of the third 1 km hip was also significantly lower (p=0.02) than the first in both trials (fig. 1b). the second, third and fourth 4 km hip (for both trials), were significantly slower (p=0.03, p=0.02 and p=0.01 respectively) compared with the first (fig. 2 a). the mean power of the fourth 4 km hip was significantly lower (p=0.01) compared with the first (fig. 2b). discussion the most important finding was that the maintenance of hyperglycaemia had no significant effect on cycling performance during a prolonged (~140 min) self-paced tt, compared with euglycaemic control subjects. this finding is surprising, since glucose oxidation rates have been shown to reach ~1.8 g.min -1 during the last 20 minutes of an intense (~70 % of v02max) 2 hour cycle bout when hyperglycaemia is table ii. mean time, power output and heart rate for ett and htt (n=7). ett htt mean time (min:s) 143:09±7:14 142:23±7:16 mean power output (w) 275±39 279±39 mean heart rate (beats·min -1 ) 160±9 158±11 values are mean ± sd. fig. 1. (a) time taken (seconds), and (b) average power (watts) for the 1 km hip during ett (•) and htt (o). * denotes a significant difference (p<0.05) from the first hip during ett and htt. + denotes a significant difference (p<0.05) from the fourth hip during ett and htt. pg94-98.indd 96 10/3/07 3:30:48 pm sajsm vol 19 no. 3 2007 97 maintained 18 compared with 1.1 g.min -1 when euglycaemia is maintained via intravenous infusion of glucose. the higher oxidation rate suggests an improved supply of oxidative substrate to the exercising muscle, and therefore could result in an improved performance. endogenous liver glucose turnover is completely suppressed and fat oxidation is inhibited under these hyperglycaemic conditions, when initial muscle glycogen levels are normal (~130 mmol.kg -1 wet wt) 18 it can be assumed that subjects in this trial would have had similar, normal muscle glycogen concentrations at the start of each tt as they followed their normal diet for 3 days prior to each trial, and had not taken part in any heavy physical activity for at least 1 day prior to each tt. this is an important consideration as weltan et al. 28,29 have demonstrated that whole-body metabolism responses are different when initial muscle glycogen levels are low (~ 80 mmol.kg -1 wet wt). under these circumstances, muscle glycogen utilisation is reduced and fat oxidation rates are elevated. however, glucose oxidation rates are unaffected by initial muscle glycogen levels when either hyperglycaemia or euglycaemia was maintained via intravenous infusion of glucose. 28,29 thus, in the current study, it is unlikely that differences in muscle glycogen concentration at the start of the tt would have had any influence on the rate of oxidation of the infused glucose. the studies of weltan et al. 28,29 indicate that the percentage contribution of each fuel substrate (i.e. muscle glycogen, plasma glucose and fat) to overall energy expenditure appears to be regulated in part by substrate availability at the start of exercise and palmer et al. 23 have shown that overall energy expenditure is similar for work bouts of the same average intensity. since exercise intensity in the current study was similar, with no significant difference between overall mean power for ett and htt (275±39 w v. 279±39 w), this suggests a similar overall energy expenditure for ett and htt. the results of this study therefore indicate that the substrate that is predominantly utilised during exercise lasting between 2 and 3 hours, has no effect on performance. this is in contrast to suggestions by gisolfi and duchman 14 and hawley et al., 17 that the inhibition of fat oxidation in the early part of exhaustive endurance events may be detrimental to performance. pacing data from this study appear to support the concept of teleoanticipation during closed loop exercise bouts. teleo anticipation is the process whereby performance is regulated by central calculations and efferent commands in an attempt to couple the metabolic and biomechanical limits of the body to the demands of the exercise task at hand. 27 the time and power for the last 1 km hip was not significantly different from the first hip (fig. 1), although the fourth hip was significantly slower. this ability to complete the last hip at a similar pace to the first is not surprising, as it has been observed previously. 20 it must also be remembered that most cycle road races end with a bunch sprint for the finish and as a result competitive cyclists would be prepared for this. it is interesting to speculate that the progressive decrement in performance from the first to the fourth hip in the l km hip, and the 4 km hip (figs 1 and 2), may be the result of afferent feedback after the first hip resetting the subconscious efferent command in order to maintain a reserve to complete the entire tt. as subjects in this study were given a financial incentive and vociferous verbal encouragement in order to complete each hip in the fastest time possible, it may be assumed that their conscious effort was the same during all hips. therefore, we suggest that a subconscious down-regulation of power output via efferent command may be responsible for the decrease in performance during the hip, prior to the last 1 km hip. although efferent command was not measured during this study, this has been shown to occur by kay et al. 20 in conclusion, the results of the current study show that in well-trained cyclists, hyperglycaemia (i.e. a plasma glucose concentration of ~ 10 mmol.l -1 ) does not improve cycling tt performance. fig. 2. (a) time taken (seconds), and (b) average power (watts) for the 4 km hip during ett (•) and htt (o). * denotes a significant difference (p<0.05) from the first hip during ett and htt. pg94-98.indd 97 10/3/07 3:30:52 pm 98 sajsm vol 19 no. 3 2007 references 1. bergstrom j, hultman e. a study of the glycogen metabolism during exercise in man. scand j clin lab invest 1967; 19: 218-28. 2. bosch an, dennis sc, noakes td. influence of carbohydrate ingestion on fuel substrate turnover and oxidation during prolonged exercise. j appl physiol 1994; 76: 2364-72. 3. bosch an, weltan sm, dennis sc, noakes td. fuel substrate kinetics of carbohydrate loading differs from that of carbohydrate ingestion during prolonged exercise. metabolism 1996; 45: 415-23. 4. brooke jd, davies gj, green lf. the effects of normal and glucose syrup work diets on the performance of racing cyclists. j sports med 1975; 15: 257-65. 5. coggan ar, coyle ef. effect of carbohydrate feedings during high-intensity exercise. j appl physiol 1988; 65: 1703-09. 6. coggan ar, coyle ef. metabolism and performance following carbohydrate ingestion late in exercise. med sci sports exerc 1989; 21: 59-65. 7. coggan ar, coyle ef. reversal of fatigue during prolonged exercise by carbohydrate infusion or ingestion. j appl physiol 1987; 63: 2388-95. 8. coyle ef, coggan ar, hemmert mk, ivy jl. muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. j appl physiol 1986; 61: 165-72. 9. coyle ef, hagberg jm, hurley bf, martin wh, ehsani aa, holloszy jo. carbohydrate feeding during prolonged strenuous exercise can delay fatigue. j appl physiol 1983; 55: 230-5. 10. coyle ef, hamilton mt, alonso ig, montain sj, ivy jl. carbohydrate metabolism during intense exercise when hyperglycemic. j appl physiol 1991; 70: 834-40. 11. defronzo ra, tobin jd, andres r. glucose clamp technique: a method for quantifying insulin secretion and resistance. am j physiol 1979; 237 (endocrinol metab gastrointest physiol 6): e214-e233. 12. dill db, edwards ht, talbott jh. studies in muscular activity. vii. factors limiting the capacity for work. j physiol (lond) 1932; 77: 49-62. 13. flynn mg, costill dl, hawley ja, et al. influence of selected carbohydrate drinks on cycling performance and glycogen use. med sci sports exerc 1987; 19: 37-40. 14. gisolfi cv, duchman sm. guidelines for optimal replacement beverages for different athletic events. med sci sports exerc 1992; 24: 679-87. 15. gordon b, kohn la, levine sa, matton m, schriver w, whiting wb. sugar content of the blood in runners following a marathon race. with especial reference to the prevention of hypoglycemia: further observations. jama 1925; 85: 508-9. 16. hargreaves md, costill dl, coggan ar, fink wi, nishibata i. effect of carbohydrate feedings on muscle glycogen utilization and exercise performance. med sci sports exerc 1984; 16: 219-22. 17. hawley ja, bosch an, weltan sm, dennis sc, noakes td. effects of glucose ingestion or glucose infusion on fuel substrate kinetics during prolonged exercise. eur j appl physiol 1994; 68: 381-9. 18. hawley ja, bosch an, weltan sm, dennis sc, noakes td. glucose kinetics during prolonged exercise in euglycemic and hyperglycemic subjects. pflugers arch 1994; 426: 378-86. 19. hawley ja, dennis sc, noakes td. oxidation of carbohydrate ingested during prolonged endurance exercise. sports med 1992; 14: 27-42. 20. kay d, marino fe, cannon j, st clair gibson a, lambert mi, noakes td. evidence for neuromuscular fatigue during high-intensity cycling in warm, humid conditions. eur j appl physiol 2001; 84: 115-21. 21. levine lw, evans j, cadarette bs, fisher ec, bullen ba. fructose and glucose ingestion and muscle glycogen use during submaximal exercise. j appl physiol 1983; 55: 1767-71. 22. levine sa, gordon b, derick cl. some changes in the chemical constituents of the blood following a marathon race. with special reference to the development of hypoglycemia. jama 1924; 82: 1778-79. 23. palmer gs, borghouts lb, noakes td, hawley ja. metabolic and performance responses to constant-load vs. variableload exercise in trained cyclists. j appl physiol 1999; 87: 1186-96. 24. palmer gs, hawley ja, dennis sc, noakes td. heart rate responses during a 4-d cycle stage race. med sci sports exerc 1994; 26: 1278-83. 25. palmer gs, dennis sc, noakes td, hawley ja. assessment of the reproducibility of performance testing on an air-braked cycle ergometer. int j sports med 1996; 17: 293-8. 26. schabort ej, hawley ja, hopkins wg, mujika i, noakes td. a new reliable laboratory test of endurance performance for road cyclists. med sci sports exerc 1998; 30: 1744-50. 27. ulmer hv. concept of an extracellular regulation of muscular metabolic rate during heavy exercise in humans psychophysiological feedback. experientia 1996; 52: 416-20. 28. weltan sm, bosch an, dennis sc, noakes td. influence of muscle glycogen content on metabolic regulation. am j physiol 1998; 274 (endocrinol metab 37): e72-e82. 29. weltan sm, bosch an, dennis sc, noakes td. pre-exercise muscle glycogen content affects metabolism during exercise despite maintenance of hyperglycemia. am j physiol 1998; 274 (endocrinol metab 37): e83-e88. pg94-98.indd 98 10/3/07 3:30:53 pm review 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the prevention of injuries among youth basketballers according to the “sequence of prevention’’: a systematic review d aarts,1 m pediatr phys ther; m barendrecht,1 m phys ther sport; e kemler,2 phd; v gouttebarge,3,4,5 phd 1 avans+ improving professionals, breda, the netherlands 2 dutch consumer safety institute, amsterdam, the netherlands 3 amsterdam umc, university of amsterdam, department of orthopaedic surgery, amsterdam movement sciences, meibergdreef 9, amsterdam, the netherlands 4 section of sports medicine, university of pretoria, pretoria, south africa 5 amsterdam collaboration on health & safety in sports (achss), amsterdam umc ioc research center of excellence, amsterdam, the netherlands corresponding author: d aarts (dannyaarts@home.nl) youth play basketball all over the world. there are approximately 450 million youth basketball players worldwide. [1] in the usa, basketball was the most popular team sport for boys (544 811) and girls (457 986) registered in the school year of 2003–2004.[2] nearly 975  000 american students participated in secondary school basketball during the 2015– 2016 academic year.[3] in 2000-2001, basketball was the most common cause of sportsand recreation-related injuries seen in usa emergency departments, with a total of 395 251 cases.[4] the proportion of cases was not evenly distributed across age groups – for boys aged 5–9 years, basketball accounted for 5% of all sports injuries, whereas it constituted 15% of cases for boys aged 10–14 years, and 26% for boys aged 15–19 years, the highest percentage for any activity in this group.[4] for girls aged 10–14 years, basketball was responsible for 15% of all sports injuries, and 18% in the 15–19 years age group.[4]in a cross-sectional study in canada among 1466 students (12-15 years old), the greatest proportion of sports injuries occurred in basketball (14%).[5] there have also been basketball injuries in africa. for example, in rwanda, one study showed that the injury rate was 3.6 injuries per player per season, while in another study in ghana, the injury incidence was 0.190 and 0.084 per 100 players during competition and training.[6,7] in a study which focused on several sports, basketball athletes were reported to have the highest injury rate.[8] overall the incidence rates for basketball are higher during matches than in training sessions.[9] results for adolescent basketball players revealed that the injury incidence varied considerably from 7.8 – 49.0 per 100 participants for girls and 5.6 – 36.8 per 100 participants for boys.[9] the national collegiate athletic association (ncaa) began collecting injury and exposure data in 1982.[10] by summarising the data from all sports, the injury cases were significantly higher in matches than in training sessions, and pre-season training session injury rates were significantly higher than both in-season and post-season training session rates.[10] there were no changes in the rates of injury over the 16 years they collected injury data. more than 50% of all injuries were to the lower extremity, with ankle ligament injuries being the most common among male basketball players.[10] marchi et al. reported in 1999 that 23% of the ankle sprains among children aged 6 to 15 years resulted in permanent complaints over 12 years of follow-up.[9] in the usa, emergency department visits are highest among school-age children.[12] over one-third of school-age children will sustain an injury sufficiently severe to be treated by a doctor or nurse.[12] besides personal suffering, high healthcare costs are also incurred. youth basketball is also responsible for many injuries in europe: after football, basketball is the sport responsible for the highest number of background: basketball is played by the youth worldwide, and various injuries occur in youth basketball. there is currently no overview of the incidence, the risk factors and preventive measures of musculoskeletal injuries among youth basketball players. objective: this systematic review describes the most common injuries among youth basketball players. the most common risk factors and various preventive measures and interventions have also been reported and discussed. methods: search strategies were built based on groups of keywords, namely ‘injury’, ‘youth basketball’, and ‘cohort’. search strategies were entered into medline and sportdiscus. titles, abstracts and full text articles were screened by two researchers. data from the included articles were extracted by one researcher and checked by another researcher. results: twenty-seven studies showed that the overall injury rate ranged from 2.64 to 3.83 per 1 000 hours of exposure. ankle (22%-37%) and knee injuries (5%-41%) were the most common injuries. risk factors for knee injuries included ankle dorsiflexion with a range less than 36.5 degrees and female athletes with greater hip abduction strength. high variations of postural sway corresponded to occurrences of ankle injuries (p=0.01, or =1.22; p<0.001, or =1.22). a core intervention (rate = 4.99/1 000 athlete exposure (aes)) focused on the trunk and lower extremity led to a reduction in injuries compared to a sham intervention (rate =7.72/1 000 aes) (p=0.02). wearing a mcdavid ultralight 195 brace reduced ankle injuries compared to the controls (hr 0.30; 95 % ci 0.17 0.90; p=0.03). conclusion: ankle and knee injuries are the most common injuries among youth basketball players. poor postural control, reduced ankle dorsiflexion and high hip abduction strength are the main risk factors. a neuromuscular warm-up, in combination with strength and stability exercises, seems to be the best training method to prevent injuries. ankle injuries can be reduced by wearing a lace-up ankle brace. keywords: basketball, injury, risk factor, preventive intervention s afr j sports med 2021;33:1-12. doi: 10.17159/2078-516x/2021/v33i1a10829 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a10829 https://orcid.org/0000-0002-5720-7999 https://orcid.org/0000-0002-0126-4177 https://orcid.org/0000-0002-1195-0998 https://orcid.org/0000-0002-3549-7091 review sajsm vol. 33 no. 1 2021 2 injuries among boys.[13] the extent of the injury problem in youth basketballers calls for preventive action based on the results of epidemiological research. the number of injuries among youth basketball players should be reduced to prevent long-term complaints or complaints into adulthood and to reduce healthcare costs. the ‘van mechelen sequence of prevention model for sports injuries’ describes four consecutive steps that lead to efficacious preventive interventions. [14,15] steps 1 and 2 consist of exploring the incidence and aetiology of musculoskeletal injuries. steps 3 and 4 consist of developing and evaluating preventive interventions.[14] a systematic review on van mechelen’s quadrants in adult basketball players has already been published, but not yet in youth basketball players.[16] therefore, we aimed to gather epidemiological information to answer the following questions: (1) what is the incidence of musculoskeletal injuries among youth basketball players?; (2) what are the risk factors of these musculoskeletal injuries among youth basketball players?; (3) what are the interventions available for the prevention of musculoskeletal injuries among youth basketball players?; and (4) how effective are these interventions on the reduction of musculoskeletal injuries among youth basketball players? methods design a systematic review was conducted on sports injury prevention among youth basketball players. this systematic review has been written in accordance with the prisma guidelines.[17] data sources and searches search strategies (appendix 1) were composed by using three groups of keywords, namely: ‘injury’, ‘youth basketball’, and ‘cohort study’. the search strategies were entered into two databases, namely medline and sportdiscus. medline was searched from october 2, 2018 up to february 7, 2019. sportdiscus was searched from october 2, 2018 up to january 8, 2019. different filters were used: humans, english, randomised controlled trial, systematic review and/or academic journal. all search terms were combined with ‘and’ and ‘or’. eligibility criteria the inclusion criteria were:  the population consists of youth (boys and/or girls) basketball players (age 6-18).  the article is written in english.  if the article is about descriptive epidemiology (step 1 of van mechelen’s model), prospective cohort design is used.  if the article is about descriptive epidemiology, incidence rates or prevalence rates are reported.  if the article is about aetiology (step 2 of van mechelen’s model), prospective cohort design is used.  if the article is about aetiology, a risk estimate is reported.  if the article is about prevention (steps 3 and 4 of van mechelen’s model), randomised controlled trial is conducted.  if the article is about prevention, incidence rates and/or effect sizes are reported. study selection titles and abstracts of the retrieved citations were independently screened by two researchers (da and vg). when the title and abstract met the inclusion criteria, the article was included for the full text selection. when the title and abstract did not contain sufficient information, it was not included for the full text selection. then the full text articles were independently assessed by two researchers (da and ja). where doubts arose concerning inclusion or exclusion of an article, a third researcher was consulted (mb). data extraction the data from the included articles were extracted by one researcher (da) in a standardised table and checked by another researcher (mb). the data extraction focused on: article information (author, year), study population (numbers, age and gender), injury definition and injury incidence. if there was information about the risk factors, preventive measures and the effect of these preventive measures, it was also included in the data collection. risk of bias appraisal to assess the methodological quality of the included articles, two different checklists were used. for the articles related to descriptive epidemiology and aetiology, the quality in prognosis studies (quips) tool was used (appendix 2). the cochrane collaboration’s tool was used for the articles related to prevention (appendix 2). for both the quips and the cochrane collaboration’s tool, six potential bias domains were assessed with a high, moderate or low risk of bias. for assessments using the quips tool, a study was considered to have a low risk of bias rated as low or moderate in all six domains, with at least four domains being rated as low.[17] if two or more domains were scored as high, the study was rated as having a high risk of bias.[17] studies that were in between were scored as having a moderate risk of bias.[18] for assessments using the cochrane collaboration tool, a study was assessed with a low risk of bias when all items were assessed as low.[18] when at least one item was assessed as moderate, the article received a score with a moderate risk of bias. a high risk of bias was rated when at least one item was assessed as high.[18] the checklists were assessed and crosschecked by two researchers (da and ja). if a difference of opinion arose concerning the scoring of an item, a consensus was reached. data synthesis and analysis the data were processed according to the four steps of van mechelen’s ‘sequence of prevention’ so that the collected information was presented clearly. the following outcome measures were used for the incidence and the risk factors: exposure, hours of exposure, hours of game exposure, athlete review 3 sajsm vol. 33 no. 1 2021 exposure, and percentages. only the results that were expressed in hours of exposure were included in the results of the overall injuries. for the effectiveness of the preventive measures, it was considered whether a reduction was found on these outcome measures. risk reduction rates were used. results search strategies a total of 381 citations were identified of which 188 were in medline and 193 in sportdiscus. of the 381 relevant citations, 19 were duplicates. after checking the titles and abstracts against the inclusion criteria, 57 potentially relevant studies were included for the full text review.[20-76] after screening the full text, 30 articles were excluded.[20-49] the reasons for exclusion were: the articles did not meet the requirements for a prospective cohort or an rct (n = 15) [2022,28,30,31,34-36,39-43,48], the articles were not specifically about youth basketball players (n = 13) [21,23-26,29,32,37,38,44-47] ,or there were no outcome measures (n = 2).[27,33] figure 1 presents the search procedure. risk of bias of the 27 included studies, 23 studies were checked using the quips tool (descriptive epidemiology and aetiology) [49-71] and four studies were checked using the cochrane collaboration’s tool (prevention).[73-76] fifteen of the 27 studies scored a low risk of bias.[49,50,56,58,59,63-65,67,69-72,74,75] the other 12 studies scored a moderate risk of bias.[51-55,57,60-62,66,68,73] an overview of the scores can be found in table 1. the incidence of musculoskeletal injuries in youth basketball of the 27 included articles for data extraction, 19 articles contained information on the incidence of musculoskeletal injuries in youth basketball. [49-67] of these 19 studies, 13 studies were about girls and boys, five studies were about girls only and one study was about boys only. the age of all participants in these 19 studies together ranged from 8 to 20 years. twelve studies were about american basketball players and seven studies were conducted in other countries (five in europe, one in japan and one in nigeria). overall injuries the overall injury rate for youth basketball players ranged from 2.64 to 3.83 per 1 000 hours of exposure.[50,51,56] the game injury rate (range 5.70 to 36.84 per 1 000 hours of game exposure) was higher than the practice injury rate (range 1.47 to 3.13 per 1 000 hours of exposure).[50,51,55,56] ankle injuries (range 22% to 37%) and knee injuries (range 5% to 41%) were the most common injuries.[50,53,54,56,57] sprains were the most common type of musculoskeletal injuries overall (ranging from 43% to 66%), followed by fractures (ranging from 4% to 12%). [52-54,57] information on the incidence of injuries is presented in table 2, appendix 3 and appendix 5. specific injuries mcguine et al. investigated the incidence of ankle sprains in youth basketballers; the rate of ankle sprain was 1.56 per 1 000 exposure (1.68 for boys and 1.44 for girls per 1 000 exposure).[63] two studies investigated the incidence of patellofemoral pain (pfp) in female youth basketball players. herbst et al. found an incidence rate for development of pfp of 0.97 per 1 000 athlete exposures (ae), the study of myer et al. found an incidence rate of 1.09 per 1 000 ae. [65,66] symptoms of anterior knee pain were likely to persist to after middle school-aged onset and to reach peak prevalence during the high school years.[68] the shoulder injury rate ranged from 0.045 to 0.061 per 1 000 ae. [60,61] fig. 1. flow chart of the search procedure review sajsm vol. 33 no. 1 2021 4 risk factors of musculoskeletal injuries in youth basketball eleven articles presented information on the risk factors of musculoskeletal injuries in youth basketball. [50,51,58,59,63,65,66,68-71] of these 11 studies, five were about girls and boys, four were about girls only and two studies were about boys only. the age of the participants in these 11 studies together ranged from 9 to 20 years. in seven of the 11 studies, research was done on american youth basketballers. in the other four studies, research was done in different countries (three in europe and one in taiwan). game vs practice the injury risk for basketball injuries in youth was higher in games than in practices in all included studies. most game injuries resulted from body contact, 46% in the study of kuzuhara et al. and 1.32/1 000 ae for boys and 1.55/1 000 ae for girls in the studies of clifton et al. [51,58,59] in the study of pasanen et al. body contact with another player was the most frequent injury situation (25%), followed by stepping or landing on another player’s foot (23%) or landing from a jump (16%). proportions of contact injuries, indirect contact injuries, and non-contact injuries were 49%, 17%, and 34%, respectively.[50] information on the aetiology of injuries is presented in table 2, appendix 3 and appendix 5. table 1. risk of bias appraisal study (questions 1 & 2) participation attribution prognostic outcome confounding analysis total risk of bias backman 2011 [71] low moderate low low low low low backx 1991 [55] moderate moderate n/a low n/a low moderate beynnon 2005 [62] moderate moderate n/a low n/a low moderate bonza 2009 [61] moderate moderate n/a low n/a low moderate clifton 2018 [58] low moderate n/a low n/a low low clifton 2018 [59] low moderate n/a low n/a low low field 2011 [68] moderate high n/a low n/a low moderate foss 2012 [67] low moderate n/a low n/a low low gomez 1996 [54] low high n/a low n/a low moderate herbst 2015 [65] low low low low moderate low low kuzuhara 2016 [51] low high low low moderate low moderate leppänen 2017 [49] low moderate n/a low n/a low low mcguine 2000 [63] low moderate low low moderate low low messina 1999 [53] moderate moderate n/a low n/a low moderate myer 2010 [66] low moderate moderate low moderate low moderate owoeye 2012 [57] moderate moderate n/a moderate n/a low moderate pasanen 2017 [50] low moderate n/a low n/a low low pilsky 2006 [69] low moderate n/a low n/a low low rechel 2008 [52] moderate moderate n/a low n/a low moderate robinson 2014 [60] moderate high n/a low n/a low moderate rossi 2018 [64] low moderate n/a low n/a low low wang 2006 [71] low low low low moderate low low yde 1990 [56] low moderate n/a low n/a low low study (questions 3 & 4) sequence allocation blinding incomplete selective other total risk of bias emery 2007 [74] low low n/a low low low low foss 2018 [72] low low n/a low low low low labella 2011 [73] low moderate moderate low low low moderate mcguine 2011 [75] low low n/a low low low low questions: (1) what is the incidence of musculoskeletal injuries among youth basketball players?; (2) what are the risk factors of these musculoskeletal injuries among youth basketball players?; (3) what are the interventions available for the prevention of musculoskeletal injuries among youth basketball players?; and (4) how effective are these interventions on the reduction of musculoskeletal injuries among youth basketball players? review 5 sajsm vol. 33 no. 1 2021 fghjdfgxdghg table 2. musculoskeletal injuries among youth basketball players: occurrence and aetiology reference total boys total girls total game practice lower extremity ankle knee leppänen [49] ir in 1 000 h of exp. 1.51 (95%ci 1.20 1.82) 1.20 (95%ci 0.86 1.62) 1.93 (95%ci 1.43 2.56) 0.07 (95%ci 0.02 to 0.16) 0.59 (95%ci 0.42 to 0.81) pasanen [50] ir in 1 000 h of exp. 2.64 (95%ci 2.23 – 3.05) girls: 32.43 (95%ci 22.01 42.85) boys: 36.84 (95%ci 24.86 48.82) girls: 1.56 (95%ci 1.06 2.05) boys: 1.47 (95%ci 1.06 1.88) 15.05 (95%ci 9.79 20.31) 6.80 (95%ci 3.25 10.34) kuzuhara [51] ir in 1 000 ahs 3.83 (95%ci 3.04 3.87) 12.92 (95%ci 7.52 18.32) 3.13 (95%ci 2.39 4.62) 0.93 (95%ci 0.54 1.32) rechel [52] ir in 1 000 ae girls: 3.60 rr 2.63 (95%ci 2.15 3.22) boys: 2.98 rr 2.05 (95%ci 1.69 2.49) girls: 1.37 boys: 1.46 messina [53] ir in athlete per season 0.56 0.49 injury risk girls: 16.0 injury risk boys: 16.9 injury risk girls: 2.0 injury risk boys: 1.8 girls: 0.1 per athlete year. boys: 0.06 per athlete year. injury risk girls: 0.71 injury risk boys: 0.31 gomez [54] ir in athlete per season 0.49 n= 135 (31%) n= 86 (19%) backx [55] ir in 1 000 hours 23.0 yde [56] ir in 1 000 playing hours 3.0 5.7 2.4 33% 5% owoeye [57] ir per 100 participants or per match 22.7 per 100 participants overall: 1.0 per match. girls: 0.9 per match. boys: 1.1 per match. total: n= 7 (21.9%) girls: n= 3 boys: n= 4 total: n= 13 (40.6%) girls: n= 6 boys: n= 7 clifton [58] ir in 1 000 ae 1.55 competition: 0.85 practice: 0.39 competition: 0.33 practice: 0.12 clifton [59] ir in 1 000 ae 1.82 competition: 0.98 practice: 0.33 competition: 0.66 practice: 0.19 robinson [60] shoulder ir in 10 000 ae 0.50 0.61 girls: 1.24 boys: 0.95 girls: 0.34 boys: 0.32 bonza [61] shoulder ir in 10 000 ae 0.47 0.45 girls: 0.76 boys: 0.90 girls: 0.32 boys: 0.30 beynnon [62] ankle ir in 1 000 persondays 0.42 1.90 girls: 1.90 boys: 0.42 review sajsm vol. 33 no. 1 2021 6 risk factors of lower extremity injuries an anterior right/left reach distance difference measured with the star excursion balance test (sebt) is a risk factor for lower extremity injuries in youth basketball players.[69] logistic regression models indicated that players with an anterior right/left reach distance difference greater than four cm were two and a half times more likely to sustain a lower extremity injury (p<0.05).[69] girls with a composite reach distance less than 94% of their limb length were six and a half times more likely to have a lower extremity injury (p<0.05).[69] risk factors of ankle injuries in boys’ high school basketball players, high variations of postural sway in one leg standing is a risk factor for developing an ankle injury.[70] postural sway was assessed through standing performance on one leg with open eyes and was measured on a force plate. high variations of postural sway in both anteroposterior and mediolateral directions corresponded to occurrences of ankle injuries (p=0.01, odds ratio [or] =1.22; 95 % confidence interval [ci] 1.046-1.424; p<0.001, or =1.22; 95 % ci 1.089-1.359).[70] subjects who demonstrated poor balance (high sway scores) had nearly seven times as many ankle sprains as subjects who had good balance (low sway scores) (p<0.001).[63] risk factors of knee injuries players with an ankle dorsiflexion range less than 36.5 degrees had a risk of 19% to 29% of developing patellar tendinopathy (pt) within a year, compared with 1.8% to 2.1% for players with an ankle dorsiflexion range greater than 36.5 degrees.[71] the ankle dorsiflexion was measured with the established weight-bearing lunge test. young female basketball athletes with greater hip abduction strength have an increased risk for the development of pfpneed to write this out in full first. female athletes who developed pfp demonstrated increased normalised hip abduction strength (normalised torque, 0.013 ± 0.003) relative to the referent control group (normalised torque, 0.011 ± 0.003) (p <0.05).[65] additionally, frontal plane loads contribute to increased incidence of pfp in young female basketball athletes.[66] preventive interventions and related effectiveness four studies regarding injury-preventive interventions were included. [72-75] foss et al. investigated the effects of a schoolbased neuromuscular training (nmt) programme on sportsrelated injury incidence at high school and middle school levels, focusing particularly on knee and ankle injuries.[73] the nmt intervention (core group) consisted of exercises focused on the trunk and lower extremity. the nmt intervention consisted of the following thirteen exercises: lateral jump and hold; step hold; bosu swimmers; bosu double-knee hold; single-legged lateral airex hop-hold; single tuck jump with soft landing; front lunges; lunge jumps; bosu (flat) double-legged pelvic bridges; single legged 90 degrees hop hold; bosu lateral crunch; box double crunch; swiss ball back hyperextensions. the control intervention (sham group) consisted of resisted running exercises using elastic bands. for basketball, the athletes in the core group (rate = 4.99 injuries/1 000 aes) demonstrated lower injury incidences than the athletes in the sham group (rate =7.72 injuries/1 000 aes) p = 0.002.[72] the core group showed a reduction in injuries for basketball players (p = 0.02).[72] the absolute risk reduction rate per 1 000 aes was: 2.73 (95% ci table 2 continued. musculoskeletal injuries among youth basketball players: occurrence and aetiology reference total boys total girls total game practice lower extremity ankle knee mcguine [63] ankle sprain ir in 1 000 exp. 1.56 1.68 1.44 overall: 1.56 girls: 1.44 boys: 1.68 rossi [64] back pain ir in 1 000 h of ae non traumatic: 0.3 herbst [65] patellofemoral pain ir in 1 000 ae 0.97 0.97 myer [66] patellofemoral pain ir in 100 athletes or in 1 000 ae 9.66 per 100 athletes 1.09 per 1,000 ae 9.66 per 100 athletes 1.09 per 1 000 ae foss [67] anterior knee pain in % n= 183 (26.6%) plisky [69] lower limb injuries ir in % 23.0% 23.0% wang [70] ankle injuries ir in n n= 18 (42.9%) n= 18 (42.9%) backman [71] patellar tendinopathy ir in n n= 12 (16.0%) n= 12 (16.0%) h of exp., hours of exposure; ir, incidence rate; ahs, athlete hours; ae, athlete exposure; rr, rate ratio; n, number of participants; exp.,exposure; h, hours; ci, confidence interval review 7 sajsm vol. 33 no. 1 2021 0.92, 4.54).[72] labella et al. evaluated the effectiveness of coach-led neuromuscular warm-up on reducing lower extremity injuries in young female soccer and basketball athletes.[73] the warmup was similar to previously studied nmt programmes, combining progressive strengthening, plyometric, balance, and agility exercises. athletes were instructed to avoid dynamic knee valgus and to land from jumps with flexed hips and knees. coaches for the control group used their usual warm-up. compared to controls, athletes in the intervention group had lower incidence rates per 1 000 aes of gradualonset lower extremity injuries (0.43 vs 1.22, p<0.01), acuteonset non-contact lower extremity injuries (0.71 vs 1.61, p<0.01), non-contact ankle sprains (0.25 vs 0.74, p=0.01) and lower extremity injuries treated surgically (0.00 vs 0.17, p=0.04).[73] emery et al. studied the effectiveness of a sports-specific balance training programme in reducing injury in adolescent basketball.[74] the training group and the control group were taught a standardised warm-up programme. the training group was also taught an additional warm-up component and a home-based balance training programme using a wobble board. the injury rate in the control group was 33.1 injuries per 100 participants per season (95% ci; 28.64-37.79); in the training group it was 26.3 injuries per 100 participants per season (95% ci; 22.48-30.43).[74] the basketball-specific balance training programme was protective with regard to acute onset injuries in high school basketball (rr = 0.71 95% ci; 0.5-0.99),[71] but not significant, like all the results from this study. selfreported compliance to the intended home-based training programme was poor (60%).[74] mcguine et al. investigated the effect of lace-up ankle braces on the incidence and severity of acute first-time and recurrent ankle injuries sustained by high school basketball players.[75] athletes were instructed to wear mcdavid ultralight 195 braces over a single pair of socks on both ankles for each teamorganised conditioning session, practice, or competition throughout the season. the rate of acute ankle injuries was 0.47/1 000 exposures in the braced group and 1.41/1 000 exposures in the control group (cox hazard ratio [hr] 0.32; 95% ci 0.20-0.52; p=<0.001).[75] for players with a previous ankle injury, the incidence of acute ankle injury was 0.82/1 000 exposures in the braced group and 1.79/1 000 exposures in the control group (cox hr 0.30; 95% ci 0.17-0.90; p=0.028).[75] information about the preventive interventions and effectiveness is presented in table 3, appendix 4 and appendix 5. discussion the results showed that the overall injury rate for youth basketball players ranged from 2.64 to 3.83 per 1 000 hours of exposure.[50,53,56] ankle injuries (22%-37%) and knee injuries (5%-41%) were the most common injuries.[50,51,54,56,57] several risk factors for developing these injuries were mentioned in the results section, including an anterior right/left reach distance difference, high variations of postural sway and an ankle dorsiflexion range of less than 36.5 degrees. the anterior right/left reach distance and the variations of postural sway were both measured with a static balance on one leg. this may indicate that poor static balance on one leg, in particular, is a predictor of developing lower extremity injuries in youth basketball players. for the preventive measures, results showed that a core intervention focused on the trunk and lower extremity led to a reduction in injuries (p=0.02).[72] the basketball-specific balance training programme was protective with regard to acute-onset injuries in high school basketball.[74] another effective preventive measure was wearing a mcdavid ultralight 195 brace. this brace reduced acute ankle injuries. similarities and differences with other studies in 16 of the 27 included articles, research was done on american youth basketball players. the rules of the basketball federation in america (nba) and the rules of the basketball federation in europe (fiba) are different. the study of madarame suggested that women’s basketball games are played in a different manner in each region of the world.[76] this could mean that the incidence and risk factors of injuries are different in each region of the world for women/girls. for european basketball girls, and probably also boys, more research must be done into incidence, aetiology and preventive measures. compared with the overall injury rates in adult basketball players (ranged from 0.05 to 12.92 per 1 000 hours of exposure),[16] the overall injury rate in youth basketball players (2.64 to 3.83 per 1 000 hours of exposure) is less and closer together. however, in the review of kilic et al. there is only one article that describes the incidence in 1 000 hours of exposure. in accordance with the review of kilic et al. [16], the ankle and knee are the most common injuries in youth basketball. for ankle injuries, a high postural sway was a risk factor in both reviews.[16,70] because ankle and knee injuries are most common among the youth and adults, it seems best to reduce these injuries in the youth. it would therefore be best to start with preventive measures for the youth and to adjust the corresponding youth exercises for adults later. the injury rate in games was higher than in practice in all included studies. this is similar to other sports.[9] in youth basketball, body contact is the main reason for injuries in games.[50] at training sessions, there are forms of practice with no body contact. the competitive pressure will probably also be a reason for more injuries in games and this should be investigated in future studies. methodological aspects it was hard to compare the findings between studies because the denominator varied from 1 000 person-days to 1 000 exposures and athletes per season. for the results of the overall injury rates, only results expressed in hours of exposure were included. the influence that this can have on the overall injury rates seems to be small because the studies with other outcome measures show roughly the same results. in future, it is advisable to use one outcome measure for all studies reporting epidemiological data. increasingly, incidence rates in all sports are being expressed as rates per 1 000 hours. this is a good review sajsm vol. 33 no. 1 2021 8 fdfdsfsd table 3. musculoskeletal injuries among youth basketball players: preventive intervention and related effectiveness reference participation and design injury definition preventive intervention outcome foss [72] n: 247 g: girls a: middle-school and high-school aged. c: us d: rct f: 1 basketball season. injury was defined as: 1. any injury causing cessation of participation in the current session. 2. any injury that caused cessation of participation on the day after the day of onset. 3 any fracture 4 any dental injury 5 any mild brain injury. core intervention: the core intervention consisted of exercises focused on the trunk and lower extremity, sham intervention: the sham protocol consisted of resisted running using elastic bands. the core group (rate = 4.99 injuries/1 000 aes) demonstrated lower injury incidences than the athletes in the sham group (rate =7.72 injuries/1 000 aes) p = 0.002. the absolute risk reduction rate per 1 000 aes was: 2.73 (95% ci 0.92, 4.54). the core group had a reduction in injuries (x2 =5.51, p=0.02). a total of 39 of 126 (31%) core group athletes and 55 of 121 (45%) sham group athletes sustained at least one injury. high school level, 14 of 53 (26%) core group athletes versus 17 of 30 (57%) sham group athletes incurring an injury (x2 = 7.49, p= 0.006). at the middle-school level, the number of injured athletes in the core group (25 of 73 [34%] athletes) and the sham group (38 of 91 [42%] athletes) was not different (x2 = 0.97, p = 0.33). labella [73] n: 1492 (soccer and basketball). (755 control group and 737 in intervention group). g: girls a: high-school age. c: us d: cluster randomised controlled trial f: unknown lower extremity injuries. intervention group: 20-minute neuromuscular warmup. control: control coaches used their usual warm-up. intervention athletes had lower rates per 1 000 aes of gradual-onset le injuries (0.43 vs 1.22, p<0.01), acute onset non-contact le injuries (0.71 vs 1.61, p<0.01), noncontact ankle sprains (0.25 vs 0.74, p=0.01), and le injuries treated surgically (0 vs 0.17, p=0.04). emery [74] n: 920 boys n=464 girls n=456 a: 12-18 years c: canada d: cluster randomised controlled trial. f: 1 year both groups were taught a standardised warm-up programme. intervention group: in addition, teams in the training group received an additional five-minute sportspecific balance training warm-up component for practice sessions and a 20-minute home exercise programme using a wobble board. the programme was protective of acute onset injuries in high school basketball [rr = 0.71 (95% ci; 0.5–0.99)]. the protective effect found with respect to all injury [rr = 0.8 (95% ci; 0.57–1.11)], lower extremity injury [rr = 0.83 (95% ci; 0.57–1.19)], and ankle sprain injury [rr = 0.71 (95% ci; 0.45–1.13)] were not statistically significant. self-reported compliance to the intended homebased training programme was poor (298/494 or 60.3%). the programme was effective in reducing acute onset injuries in high school basketball. there was also a clinically relevant trend found with respect to the reduction of all lower extremities and ankle sprain injuries. mcguine [75] n: 1460 (740 braced group and 720 control group. g: boys and girls a: high-school aged. c: unknown d: rct f: one basketball season (2009-2010) injury: an event that occurred during a basketball exposure that forced the athlete to stop participation and prevented the athlete from participating in basketball activities the following day. intervention group: mcdavid ultralight 195 braces were used. control: in principle, the control group did not wear an ankle brace. acute ankle injury was 68% less in braced group than in control. acute ankle injury rate braced 0.47/1 000 exposures and control 1.41/1 000 exposures ([hr] 0.32; 95% [ci] 0.20, 0.52; p = <0 .001). for players with a previous ankle injury, the incidence of acute ankle injury was 0.82/1 000 exposures in the braced group and 1.79/1 000 exposures in the control group ([hr] 0.30; 95% ci 0.17,0.90; p = 0.028). for players who did not report a previous ankle injury, the incidence of acute ankle injury was 0.40 in the braced group and 1.35 in the control group ([hr] 0.30; 95% ci 0.17, 0.52, p <0.001). the use of a lace-up ankle brace reduced the incidence but not severity of acute ankle injuries in male and female high school basketball athletes by 68% regardless of sex, age, level of competition, or bmi compared with wearing no brace. n, number of participants; g, gender; a, age; c, country where study was conducted; d, design; f, follow-up period; rct, randomised controlled trial; ae, athlete exposures; hr, cox hazard ratio; ci, confidence interval; rr, relative risk review 9 sajsm vol. 33 no. 1 2021 approach and allows some comparison across sports.[77] it is better than per exposure because not every individual takes part in a training session or game for an equal period of time. some limitations need to be addressed. the search for articles was done in two databases and only articles written in english were included. in this review, only studies with a prospective design were included to formulate valid answers to the research questions while maintaining the highest scientific quality. the databases and selection criteria used might have led to the exclusion of relevant studies with a different design or in another language. we believe that these limitations did not significantly affect the findings, because the two databases used were the most obvious ones and prospective studies were used to formulate valid answers. there is a lack of scientific literature on the aetiology of basketball-specific shoulder and lower back injuries among youth basketball players. the search for articles only revealed articles about the aetiology and prevention of ankle and knee injuries. studies on the aetiology and prevention of other specific regions of the body are lacking. little is known about the incidence of injuries to other regions of the body and this information is presented in table 2. because there are no studies into the aetiology of those injuries, prevention studies cannot be drawn up for these few common injuries. several risk factors for injuries in youth basketball players were found in this overview. conclusions on the risk factors for youth basketball injuries are derived from only one study. therefore, it is important to be cautious when interpreting these risk factors. more research into risk factors for youth basketball injuries is recommended. in some studies, the ages of the children used were not specifically described and in other studies an average age was used. in two studies, the maximum age of the included participants was 20 years. [49,71] because participants older than 18 years were a small group of the participants of all included articles, we believe that our results are still representative of youth basketball players. all included studies scored a low or moderate risk of bias. this means that we must be careful with some of the conclusions. this systematic review scores a level of evidence 2. a level of evidence 2 applies to the results of the incidence and risk factors. a level of evidence 1 applies to the conclusions from the studies on preventive measures, except for the study by labella et al., which scores a level of evidence 2. implications for practice based on the results from the included studies on risk factors, it seems advisable to do a screening at the start of the season for ankle mobility, the strength of the hip abductors and the reach distance of the lower extremities. if there are risk factors, they will have to be addressed in a preventive program to prevent injuries.[78] also, it is advisable to perform a neuromuscular warm-up in combination with performing weekly strength and stability exercises for the trunk and lower extremity and to wear a lace-up ankle brace around both ankles in each training session and each game. conclusion the conclusions of this systematic review are predominantly based on american youth basketball players, showing an overall injury rate ranging from 2.64 to 3.83 per 1 000 hours of exposure. ankle and knee injuries were the most common injures among youth basketball players. the main risk factors for injuries in youth basketball were: playing games, anterior right/left reach distance difference greater than four cm, an ankle dorsiflexion range less than 36.5 degrees and high variations of postural sway in one leg. physical therapists and coaches can use the sebt to identify youth basketball players who are at increased risk for a lower extremity injury. the hip strength and the ankle dorsiflexion can also be tested in knee complaints or to prevent pt and pfp. a neuromuscular warmup in combination with performing weekly strength and stability exercises for the trunk and lower extremity currently seems to be the best training method for preventing injuries in youth basketball players. acute ankle injuries can be reduced by wearing a mcdavid ultralight 195 brace. for the preparation of specific prevention programmes in youth basketball, further research on the incidence and especially on the aetiology is needed. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: da wrote this manuscript as a graduation project for his course (master of pediatric physical therapy), collected the data and performed the analysis. vg was the project leader for this manuscript, conceived and designed the study, collection of data, interpretation of the results and the writing/adaptation of the text. mb was the project supervisor and was involved in the design, collection of data, interpretation of the results and the writing/adaptation of the text. ek works at the dutch consumer safety institute and was involved with the writing/adaption of the text and with preparing the manuscript for publication. references 1. fiba the international basketball federation. fiba basketball overview facts and figures. http://www.fiba.com/presentation#|tab=element_2_1. 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https://doi.org/10.4085/1062-6050-173-16 https://www.ncbi.nlm.nih.gov/pubmed/22065184 https://www.ncbi.nlm.nih.gov/pubmed/22065184 https://www.ncbi.nlm.nih.gov/pubmed/22065184 https://www.ncbi.nlm.nih.gov/pubmed/22065184 https://doi.org/10.1001/archpediatrics.2011.168 https://www.ncbi.nlm.nih.gov/pubmed/17304001 https://www.ncbi.nlm.nih.gov/pubmed/17304001 https://www.ncbi.nlm.nih.gov/pubmed/17304001 https://doi.org/10.1097/jsm.0b013e31802e9c05 https://www.ncbi.nlm.nih.gov/pubmed/21795671 https://www.ncbi.nlm.nih.gov/pubmed/21795671 https://doi.org/10.1177/0363546511406242 https://www.ncbi.nlm.nih.gov/pubmed/?term=madarame%20h%5bauthor%5d&cauthor=true&cauthor_uid=30036984 https://doi.org/10.3390/sports6030065 https://doi.org/10.1136/bjsm.34.2.133 https://www.ncbi.nlm.nih.gov/pubmed/27095747 https://www.ncbi.nlm.nih.gov/pubmed/27095747 https://doi.org/10.1136/bjsports-2016-096256 original research 69 sajsm vol. 28 no. 3 2016 experiences of psychosocial and programme-related barriers to recovery in lifestyle interventions for noncommunicable diseases p skowno, phd1, w derman, mbchb, ffims, phd2, d j stein, mbchb, frcpc, phd3, c e draper, phd1 1 division of exercise science and sports medicine, department of human biology, university of cape town, south africa and sport science institute of south africa, newlands, south africa 2 department of orthopaedics, university of stellenbosch, south africa 3department of psychiatry and mrc unit on anxiety and stress disorders, university of cape town, south africa corresponding author: p skowno (pskowno@gmail.com) the majority of recent global deaths are due to noncommunicable diseases (ncds)[1]. many of these diseases are preventable by modifying key risk factors such as unhealthy diet, physical inactivity, tobacco use and harmful alcohol use [1]. however, the complex nature of the disease experience make it unavoidable to dismiss the challenges inherent in sustainable behaviour modification[2]. this is demonstrated by the continuing increase in global incidence of ncds. in turn, the development of more individualised, patient-centred treatment for these cases may require a more comprehensive research strategy to better understand patient experiences of ncds and their participation in lifestyle intervention programmes. this is often achieved through the application of qualitative research strategies. the application of qualitative and mixed methodologies in health science research has resulted in a corresponding increase in literature detailing patient experiences of ncds and the recovery process[3–7] to date, a number of reviews[3] and systematic reviews[4,5] have collated patients’ experiences of chronic heart failure, and qualitative research has distinguished genericand disease-specific experiences of ncds[6]. elderly patients experience chronic heart failure as debilitating and distressing. there is a great deal of uncertainty, especially at an advanced stage of illness and inefficacy in self-care[4]. social isolation, living in fear, and losing a sense of control were included as prominent themes in a subsequent review of the topic[5]. adaptation to a new sense of self is suggested as influencing self-care behaviours[3]. moreover, patients recovering from myocardial infarctions noted difficulties in making lifestyle changes[7]. accordingly, findings called for increased long-term support and monitoring, as well as group work to enhance the sharing of experiences[7]. a systematic review of patient experiences of chronic heart failure noted the nature of health service encounters as an important factor influencing patient health trajectories[5]. it incorporates access, continuity and quality of care, as well as comorbid conditions and personal relationships, and thus plays an important role in developing and improving the delivery and use of lifestyle interventions for patients with ncds[5]. research of patient experiences of cardiac rehabilitation highlights the barriers to adherence or attendance. using qualitative methodologies, a systematic review and metasynthesis of cardiac rehabilitation studies identified physical and personal barriers to participation[8]. examples of physical barriers included a lack of transport and financial constraints. personal barriers may include a patient feeling embarrassment about participation, or misunderstanding the reasons for the onset of the disease, or the purpose of rehabilitation. what is less evident, however, are the characteristics and experiences of ncds’ cohorts with multiple comorbidities who are participating in lifestyle intervention programmes. extensive descriptions of these cohorts could potentially guide the development of more patient-centred interventions. therefore the aim of this paper is to describe the role of factors which may hinder a patient’s physical and psychological progress in a lifestyle intervention programme for ncds. specifically, the paper’s objectives are to outline psychosocial as well as programme-related factors which might contribute towards less successful physical and mental health outcomes in patients with ncds. background: the majority of global deaths are due to noncommunicable diseases, largely preventable and treatable utilising behavioural interventions. objectives: the study investigated patients’ experiences of a lifestyle intervention programme for noncommunicable diseases (ncds), and the influence that psychosocial and programme-related barriers had on patients’ ability to improve their well-being. methods: fourteen patients with ncds were interviewed before and on completion of a 12-week lifestyle intervention programme at a sports and exercise medicine clinic. thematic analysis techniques were used to analyse interview data. results: patients described their experiences of ncds diagnosis as traumatic, and their own relationship with their bodies and with the disorder(s) to be vulnerable and significantly challenging. professional incompetence and unethical treatment were included as barriers to recovery. barriers specifically relating to the programme included scheduling, as well as the online assessment component. those reporting more premorbid psychosocial barriers were more likely to experience current complications, whether diseaseor treatment-related, often emphasising the negative influence of programme and professional-related problems. conclusion: qualitative methodologies enabled the study to yield clinically relevant insights with respect to patients with ncds. accounting for the trauma and vulnerability experienced by this cohort may assist in the development of more patient-centred interventions and sustainable secondary prevention of ncds. keywords: chronic diseases of lifestyle; intervention evaluation; psychological risk factors; social support; professional conduct s afr j sports med 2016;28(3):69-73. doi: 10.17159/2078-516x/2016/v28i3a1237 http://dx.doi.org/10.17159/2078-516x/2016/v28i3a1237 original research sajsm vol. 28 no. 3 2016 70 methods study design the study used qualitative methodology. data collection and analysis involved semi-structured interviews and thematic analysis respectively. study setting u turn medical is a multi-disciplinary, comprehensive lifestyle intervention programme centred on the patient. the 12-week programme is designed to provide optimal health care for patients with a range of established chronic diseases, including cardiovascular disease, metabolic and chronic respiratory disorders. the programme manages established disease states and recognised risk factors, and aims to improve a patient’s functional capacity. it provides risk screening, medical assessment, supervised exercise sessions, injury prevention strategies, dietary education and psychosocial support. individualised exercise and lifestyle prescriptions are developed for patients during preliminary one-on-one exercise sessions with a biokineticist. exercise, dietary, and psychosocial prescriptions are based on findings from baseline medical, exercise and psychosocial assessments. the majority of patients subsequently participate in group exercise sessions held three times a week in a morning or afternoon session. the group exercise sessions are supervised by a biokineticist. a sports physician is in attendance to provide a prompt and appropriate response to any potential emergencies during exercise sessions. prior to completion, patients are reassessed by a biokineticist and a sports physician. this may be followed by an additional 12-week programme if indicated. participants participants were identified and recruited from a cohort of patients with ncds starting the u turn medical[9] lifestyle intervention programme. convenience sampling was deemed the most suitable strategy for the investigation, based on the availability of new intakes into the programme and referral from biokineticists and doctors at clinics. cases meeting referral criteria for the programme were included in the study. the majority of participants were referred to by programme staff as ‘cardiac patients’. fourteen individuals consented to being interviewed at the start of the programme. eleven of the 14 were available for recorded interviews at the end of programme. two participants submitted written responses due to the reported inconvenience of returning to the study site, and one participant who did not complete the programme did not respond to requests for a follow-up interview. of the 11 participants interviewed, two withdrew from the programme due to health complications, with one reporting the intention of resuming the programme at the time of the second interview. an overview of participant characteristics is detailed in table 1, and reflect similar demographic trends to related patient populations, as reported in related studies[9]. data collection interviews before and after the intervention were semistructured, consisting of open-ended questions within a flexible structure to define a specific area of inquiry, as well as divergence to another area if necessary[10,11]. the questions for both interviews are detailed and italicised in table 2. interviews took place in a consulting room at the clinic and recorded using a digital voice recorder. they were conducted by the first author, a registered counselling psychologist, and lasted between 15 and 50 minutes respectively. on average, the initial interview was conducted during the participant’s second or third week after the physician’s assessment. the second interviews were held any time from the last few weeks of the participant’s programme to six months thereafter. the recordings were subsequently transcribed and analysed. ethical considerations ethical approval for this study was obtained from the human research ethics committee of the faculty of health sciences at the university of cape town (hrec ref 332/2007) in accordance with the helsinki declaration. participants gave their signed, informed consent. data analysis interview data were analysed using thematic analysis, a userfriendly and intuitive method of identifying and selecting central themes and patterns in data[12]. it is a flexible method and can be adapted into numerous research designs, irrespective of the researcher’s theoretical background[13]. thematic analysis identifies basic features of the data that are of interest to the researcher[12]. this is achieved through coding, a process of extracting the most basic, yet meaningful segments of raw data from a data set[12]. following the coding process, themes were identified. themes relate the important aspects of data to the study’s research question[12]. they occur relatively frequently within the data set and carry some degree of meaning[12]. the study made use of qsr nvivo 10 data analysis software. after the start of the preliminary analysis, a thematic framework was constructed in which to consolidate similar themes and perceive the differences from others. the themes identified in the data set were categorised as: psychosocial barriers and professional and programme-related barriers to progress in the programme. results the following section initially describes premorbid and disease-related psychosocial barriers commonly reported by the participants. it subsequently outlines other programmerelated factors participants reported as influential in impeding potential improvements in health. specifically, the importance of professional and ethical conduct by health practitioners (in the programme and in general) is highlighted, as well as a number of technical issues which may have been perceived as frustrating enough to interfere with progress. theme 1: psychosocial barriers participants were asked whether they believed that any original research 71 sajsm vol. 28 no. 3 2016 personal history, relationships or qualities may have hindered their ability to improve their health during the programme. a number of participants reported premorbid and or current psychosocial difficulties. a common theme identified among the comments from the patients included negative responses to the initial diagnoses of ncds. premorbid and current psychosocial barriers psychosocial barriers ranged from childhood traumas to chronic mood disorders and multiple current stressors, all of which complicated the treatment process of those afflicted. not all accounts of premorbid or current psychosocial problems, however, were indicative of poor progress in the programme. of the six participants identified as currently experiencing or having a history of psychosocial difficulties, three reported achieving physical progress by the end of the programme. the remaining three, however, experienced continued difficulties in initiating and or maintaining health changes. current psychosocial stressors involved work, difficult relationships, comorbid conditions and drug side effects which complicated the treatment process, family commitments, and problems related to retirement. responses to ncds there were varied reactions by participants to their respective health challenges. for some, the decline in physical condition came as a shock, highlighting a disconnection between perceived and actual health status:  correct. i thought, you know, “i’m a fit, healthy guy, and i exercise a lot, and i’m looking after my health, i don’t smoke. and here i’m getting a heart transplant. what’s that about?” [laughs] (male, 50 years).  ...the only adverse thing was that i couldn’t bring myself to actually say, “you had a heart attack”. and i still don’t even like saying it now. (male, 72 years) many participants responded pessimistically to their initial ncd event and diagnosis. for a few, this included blaming themselves for their poor health:  ja! and, and this has made me think, “you know what, you are 54, you’ve buggered around for thirty something years, or forty years, since i’ve been overweight, taking chances.” i mean, some of the weight is, medically... caused, and the other is completely self-induced. i eat too much, i drink too much, i smoke 40 cigarettes a day. um... and used to eat every second day to try and control it. so ... i’ve done all that damage [3 sec pause] now you’ve got to a point where you’re going to have to [3 sec pause] live with what you’ve got, and get it to be the best... functioning body. which i’ve never done to my poor body. because i’ve always had so many things wrong with it, it’s like, “oh for god’s sake something else”. (female, 55 years). others experienced a significant loss in confidence, particularly in their bodies. these reactions often resulted in a sense of helplessness and decreased motivation to make the necessary health changes: table 1. demographic and medical characteristics of participants (n=14) age (2014) 15-59 60-84 5 9 sex male: female 10:4 race white coloured 12 2 employment full time part time retired 8 (all self but 1) 1 4 referral to u turn fedhealth medical scheme cardiologist/ other 6 7 premorbid best (before diagnosis/ event) 0-3 years over 3 years 9 5 interviews completed interview 1 interview 2 14 (in person) 11 (in person) 2 (written) activities since u turn completed programme, then own gym completed more programmes did not complete, but did some exercise 4 7 2 social support married single divorced 9 3 2 primary diagnosis cardiovascular disease metabolic disorders 13 1 table 2: semi-structured interview framework interview 1: when was the last time you remember feeling your (psychological, physical, spiritual) best? what happened since then? detail the events that brought you to the u turn programme where you referred by fedhealth? (if not mentioned) what are your expectations of the programme? what do you hope will be achieved? (if already commenced) what are your impressions so far of the programme? what personal qualities may assist you in successfully completing this programme? how would you define the term resilience? how does it apply to your life? is there any potential benefit to what has happened to you? what aspects of your recovery are within your control? (or not) original research sajsm vol. 28 no. 3 2016 72  so, it’s my first... feeling of being in a health problem, of having a health problem, and thinking, “i’m now scared if i have a heart attack or something!” you know? can i push myself? i don’t know. (female, 52 years).  i am so lacking in confidence in myself i find it even difficult i went to the shop with my wife earlier today, uh, because i’m not even driving anymore, i’m that uncomfortable you know... i don’t recognise this body at all right now... this is definitely the most traumatic event i’ve had to deal with. (male, 61 years). theme 2: professional and programme-related problems professional incompetence several participants reported experiencing dissatisfaction with the healthcare provided by at least one professional, either currently, or in the past. reasons included unethical conduct or the failure to diagnose and effectively treat certain complications. that said, the professionals concerned were not directly involved with the clinic, or the u turn medical programme. all of the above factors had the potential to impede the participants’ progression towards healthier outcomes, and even adhering to the programme itself, as experienced by a male participant of 61 years. he dropped out of the programme because of poorly managed, severe side effects from his anticoagulant medication, leading to an overall sense of helplessness and demotivation:  the feeling is, you know, how does anybody actually know what is going on with this heart of mine? is it improving or isn’t it? you know? (male, 61 years). a female participant of 55 years relayed an unpleasant interaction with her cardiologist:  um, had an appalling... doctor who said i didn’t deserve the heart i had because i was so fat. um, because i apparently had the heart of a 35 year old and i’m 54. um, because there is no narrowing, there’s no cholesterol issues, he says, nothing. um, but... he cleared me for that, discharged me, and now i’ve just been panicking ever since then. never saw him again, refused to consult with him. (female, 55 years). another participant communicated her unease with the ability of previous biokineticists in managing certain patient populations. moreover, a number of participants had complicated presenting problems at programme intake, and communicated a lack of faith in their doctor’s ability to correctly manage their conditions. administrative and logistical problems a few participants found the timing of the programme to be too intensive. they reasoned that three times a week, at over 90 minutes a session, took significant time away from other commitments. the times that were offered were additionally considered to be inadequate and problematic from a commuter’s perspective. several participants expressed frustration with u screen, an online assessment and educational component of the programme. problems included the software, where a number of participants were required to recomplete and resubmit assessments on several occasions. many participants, although being at least partially computer literate, struggled with accessing and completing the forms from tablets and mobile phones and requested paper versions. others simply found the educational modules to be unnecessary and time-consuming, as they felt that had sufficient knowledge of the topics covered and did not need to complete the modules. discussion the study investigated patients’ experiences of a lifestyle intervention programme and the influence of psychosocial and programme-related factors on their ability to improve their physical and psychosocial well-being. the most important finding was that nearly all the participants experienced at least a moderate degree of trauma at the time of their initial diagnosis. this occurred in individuals with varying ncds, as well as premorbid physical and psychosocial well-being. similar accounts can be found in related research[3–7,14]. furthermore, the impact of earlier psychosocial difficulties, rather than the events themselves, was considered. while not all participants experienced a major cardiac event, most reported that their lives and confidence in their bodies had been significantly altered by the diagnosis. for some, this included a sense of disconnection between perceived and actual health, and for others it resulted in self-blame. while reviews by yu et al. and jeon et al. respectively highlighted the distress and uncertainty experienced by patients living with chf, both reviews focused on a significantly older population[4,5]. another study of patients recovering from heart attacks identified the uncertainty patients felt between being ‘well’ and still being ‘ill’ after hospital discharge, as well as the need for longer-term support in managing prescribed changes in lifestyle[7]. some participants who reported past psychosocial difficulties complained of having current problems and comorbid conditions. not all accounts of premorbid difficulties, however, were indicative of poor physical progress during the programme. this serves as another reminder of the multifactorial and subjective nature of psychosocial barriers, and the need for more individualised assessment and management of ncds[2,15]. themes relating to professional incompetence were included as a concern for several participants. specifically, participants experiencing chronic, undiagnosed (or misdiagnosed) symptoms had less faith in the ability of healthcare practitioners to treat their primary ncds. moreover, a number of responses relating to professional misconduct emphasised the potentially negative impact practitioners have on their patient’s progress. related findings are reported in ncds literature, with the nature of health service encounters being reported as an important factor impacting on the ability of patients’ with chronic heart failure to manage their disease[5]. lastly, technical and administrative problems included the original research 73 sajsm vol. 28 no. 3 2016 timing of classes, as well as the electronic and online assessments which were faulty or inaccessible to patients who were not computer literate. a few participants found such problems to be detrimental to their progress. for most patients, the quality of interactions with practitioners and with the programme staff was considered more important to their progress than the above factors. these findings are found in other rehabilitation and ncds literature, which emphasise the importance of social support and health education in a patient’s lives[14]. limitations it is of paramount importance that researchers account for their role as a research instrument in qualitative methodologies. researchers’ personal values and biases may impact the trustworthiness of the collection, analysis and reporting of participant responses. moreover, the power dynamics between researcher and participant should always be considered. a number of the participants may have felt pressured into volunteering for the interviews, or disclosing more than usual because the researcher was often presumed to be a member of the programme’s medical team. though the researcher took pains to rectify this misunderstanding, it may have influenced aspects of the sampling and quality of responses. patients unwilling to disclose psychological information to u turn medical staff may not have known that the study would be conducted by an external researcher, who was bound by researcher-participant confidentiality. volunteers may have been similarly misinformed and thus they restricted their responses to more socially desirable or edited versions. lastly, contextual constraints and limits on the research process require due consideration. data collection at the sport and exercise medicine (sem) clinic was limited by patient intake into the u turn medical programme, which was infrequent at times. in addition, staff may have inadvertently used the recruitment stage as more of a referral system, often only remembering to introduce the study to patients who had mentioned psychological problems early in the intake process. this may have created a bias in the cohort who contributed to this investigation. conclusion noncommunicable disease events and diagnoses are undoubtedly traumatic for many, and may require much resilience to overcome them. the study promotes the use of individualised assessment strategies to ascertain the nature and perceived importance of any trauma or related barriers experienced by patients with ncds. specifically, using semistructured interviews, the study allowed for in-depth descriptions of ncds patients’ perceptions of and responses to their illness, as well as their recovery process. by providing a flexible and individualised investigative approach the study was able to yield clinically relevant psychosocial insights of patients with this complex condition. it is hoped that such techniques be included in the routine assessment of patients with ncds which, in turn, will further the development of patient-centred interventions in these and other disease cohorts. conflict of interest: one of the authors (wd) co-directed the u turn medical programme at the time of data collection and analysis. references 1. world health organisation. global status report on noncommunicable diseases 2010. (alwan a, ed.). geneva: world health organisation; 2011. http://www.cabdirect.org/abstracts/20113168808.html. accessed november 2, 2014. 2. matheson go, klügl m, engebretsen l, et al. prevention and management of non-communicable disease: the ioc consensus statement, lausanne 2013. br j sports med 2013;47(16):1003-1011. doi:10.1136/bjsports-2013-093034. 3. welstand j, carson a, rutherford p. living with heart failure: an integrative review. int j nurs stud 2009;46(10):1374-1385. doi:10.1016/j.ijnurstu.2009.03.009. 4. yu dsf, lee dtf, kwong ant, et al.. living with chronic heart failure: a review of qualitative studies of older people. j adv nurs 2008;61(5):474-483. doi:10.1111/j.1365-2648.2007.04553.x. 5. jeon y-h, kraus sg, jowsey t, et al. the experience of living with chronic heart failure: a narrative review of qualitative studies. bmc health serv res 2010;10(77):1-9. doi:10.1186/1472-6963-10-77. 6. corcoran kj, jowsey t, leeder sr. one size does not fit all: the different experiences of those with chronic heart failure, type 2 diabetes and chronic obstructive pulmonary disease. aust heal rev 2013;37(1):19-25. doi:10.1071/ah11092. 7. gregory s, bostock y, backett-milburn k. recovering from a heart attack: a qualitative study into lay experiences and the struggle to make lifestyle changes. fam pract 2006;23(2):220-225. doi:10.1093/fampra/cmi089. 8. neubeck l, freedman sb, clark am, et al.. participating in cardiac rehabilitation: a systematic review and meta-synthesis of qualitative data. eur j prev cardiol 2012;19:494-503. doi:10.1177/1741826711409326. 9. derman w, schwellnus m, hope f, et al. description and implementation of u-turn medical, a comprehensive lifestyle intervention programme for chronic disease in the sport and exercise medicine setting: pre-post observations in 210 consecutive patients. br j sports med 2014;48(17):1316-1321. doi:10.1136/bjsports-2014-093814. 10. britten n. qualitative interviews in medical research. bmj 1995;311(6999):251-253. 11. potter j, hepburn a. qualitative interviews in psychology: problems and possibilities. qual res psychol 2005;2(4):281-307. doi:10.1191/1478088705qp045oa. 12. braun v, clarke v. using thematic analysis in psychology. qual res psychol 2006;3(2):77-101. doi:10.1191/1478088706qp063oa. 13. boyatzis re. transforming qualitative information: thematic analysis and code development. london: sage; 1998. 14. de sousa pinto jm, martín-nogueras am, morano mtap,et al.. chronic obstructive pulmonary disease patients’ experience with pulmonary rehabilitation: a systematic review of qualitative research. chron respir dis 2013;10(3):141-157. doi:10.1177/1479972313493796. 15. coulter a, ellins j. effectiveness of strategies for informing, educating, and involving patients. bmj 2007;335(7609):24-27. doi:10.1136/bmj.39246.581169.80. introduction the 2004 summer olympic games in athens represented the 4th olympic games to which the south africa sent an olympic team since readmission to olympic competition in 1992. in accordance with the number of athletes in the team and in keeping with international olympic committee (ioc) allocations and previous experience and recommendations, the medical team was assembled. 1,2 as spaces on the medical team are very limited, the correct balance of medical service provision remains a difficult endeavour. in total, the medical team comprised 11 members including 4 sports physicians, 6 physiotherapists and a sport psychologist. in contrast to sydney 2000, none of the large teams in the south african squad were competing in remote cities and therefore all medical services were centralised. this report describes the nature and profiles of the consultations for both the athletes and officials. the objectives of this report are therefore to examine the delivery of medical services and compare the profile of medical consultations over the last two olympic games, as well as provide data for planning of medical support to future multi-coded sports events of similar nature. methods the medical records and histories of athletes were obtained through clinical evaluation opportunities during the work-up in the operation excellence programme (the preparation programme of the national original research article profile of medical and injury consultations of team south africa during the xxviiith olympiad, athens 2004 abstract objective. this descriptive study was undertaken to document the nature of medical and injury consultations of the athletes and officials of the south african team at the 2004 olympic games, and to provide data for planning future events. setting. south african medical facility, 2004 olympic games, athens, greece. methods. total number of consultations and diagnoses were ascertained from medical logs and patient files which were completed daily by the members of the medical team. a retrospective clinical audit of medical records was then undertaken and the data were then compared with similar data collected during the sydney 2000 olympic games. acute and chronic-soft tissue (muscle strain, ligament sprain, tendon injury, contusion or laceration) and bony injury were analysed in terms of nature of injury, grading of severity and anatomical region injured. main outcome measures. number of consultations due to medical complaints or injuries among athletes and officials. results. a total of 180 medical consultations were logged during the time in athens while 348 consultations were logged in sydney. the daily consultation rate was 6 per day in athens compared with 13 per day in sydney. in athens, 84% of consultations were with athletes and the remainder (16%) with officials – this was similar to sydney. the most common medical complaints in athens were dermatological (16%), ent (13%), and respiratory (8%) in nature, which contrasts with the profile of consultations in sydney (ent 18%; neurological system 16% and respiratory 16%). acute injury and chronic injury accounted for 26% and 14% of consultations respectively. in athens, the most common acute correspondence: professor wayne derman uct/mrc research unit for exercise science and sports medicine sport science institute of south africa newlands 7700 cape town, south africa tel: 27-21-659-5644 fax: 27-21-659-5633 e-mail: wayne.derman@uct.ac.za wayne e derman (mb chb, bsc (med)(hons), phd, facsm, ffims) uct/mrc research unit for exercise science and sports medicine, sport science institute of south africa, cape town 72 sajsm vol 20 no. 3 2008 and chronic injuries were soft-tissue injuries. the most common acute injury regions were the foot and ankle (25%), upper leg (17%) and knee (17%). a total 77% of acute injuries were grade i, 17% grade ii and 6% grade iii in severity. the most common chronic injury regions were foot and ankle (32%), lumbar spine (32%), and shoulder (11%). these injury profiles were similar to those documented in sydney 2000. conclusions. injury and illness complaints of the south african team were fewer in athens 2004 compared with those documented during sydney 2000. this can be attributed to local environmental conditions and travel across time zones. these data should be useful for planning medical services for future multicoded events. the analysis of the nature of consultations suggests that it should be a prerequisite for physicians travelling with a multi-coded events team to have broad knowledge of both medical and injury management of athletes. specifically, a sound knowledge of the management of soft-tissue injury is an important prerequisite for the personnel of the medical team. profile of medical.indd 72 10/17/08 11:24:14 am olympic committee of south africa) and at preparation camps in the build-up to the olympic games. at each opportunity a hard-copy medical record was completed and the data transferred to an electronic database. this medical database was taken to athens. athletes were defined as the members of the team engaged in competition and officials were defined as team or athlete coaches, team managers, team technical staff, administration officials, medical staff and national olympic committee members. we used data from patient files and medical encounter forms to determine the use of the medical services. data were collected over 30 days, starting when the team arrived in athens (1 sept) until the end of the olympic games (30 sept). the nature of injury, medical complaint, or treatment was recorded on a specifically designed medical encounter form at the time of examination or treatment by the examining physician. the datasheets were collected and retrospective clinical audit of the encounter forms and patient files was performed. the term ‘injury’ was defined as any complaint that required medical diagnosis and management. acute injury was defined as any new injury that required medical or physiotherapy intervention and was subsequently graded i, ii or iii. grade i injuries required on-field intervention but the athlete was able to continue competition or training, grade ii injuries required that the athlete was removed from participation or training for less than 48 hours, and with grade iii injures, the athlete was unable to participate in training or competition for more than 48 hours. chronic injuries were defined as either preexisting injury or acute injury that subsequently required ongoing medical evaluation and management. results olympic preparation programme medical and scientific preparation of the team began in 2002 with some members of the potential olympic squad joining operation excellence. athletes underwent medical and scientific evaluations both regionally (between 2002 and 2004) and at two camps: the first in pretoria in january and the second in pretoria in august 2004, before departure for athens. a total of 137 pre-participation medical assessments were conducted at these camps. the pre-participation programme included not only medical but also dietary, physiological, psychological and dental evaluations. consultations and treatments during the olympic games in total 159 team members travelled to athens. the team comprised 107 athletes from 18 sports codes and 52 officials; 180 formal medical consultations were conducted in the 30-day period. of these consultations 84% (152 consultations) involved athletes and 16% (28 consultations) involved officials. the rate of formal consultations averaged 6 per day. this figure does not include informal consultations by the sports physicians in the physiotherapy rooms, patients consulted at field-side, at pool-side, at the track or any other venue. the daily rate of consultations and relative distribution of consultations between athletes and officials for both sydney 2000 and athens 2004 is shown in fig. 1. relatively more consultations were conducted on a daily basis during sydney 2000 compared with athens 2004. the relative distribution of medical consultations between athletes and officials in athens was similar to that documented in sydney. of the consultations conducted with officials, 36% were due to injury mostly sustained through training with the athletes and 64% of consultations with officials were due to medical-related problems. the nature of the main complaint requiring medical consultation with respect to the athletes is displayed in fig. 2. in athens 2004, 60% of all consultations resulted from a medical (non-injury) complaint while 40% of all consultations were due to injury. this distribution of consultations was similar to that reported after sydney 2000 (69% non-injury related; 31% injury related). the main medical complaints noted during athens 2004 were dermatological (16%), ear, nose and throat (ent) related (13%); and respiratory related (8%). these data contrast somewhat to those reported after sydney 2000, where the main complaints were respiratory (16%), neurological (16%) and ent (18%) in nature. acute and chronic injury during athens 2004 accounted for 26% and 14% of consultations respectively, which contrasts slightly with injury data from sydney 2000, where 14% and 17% of consultations were due to acute and chronic injury respectively. data from sajsm vol 20 no. 3 2008 73 fig. 1. average daily consultation rate and relative percentage of total consultations for athletes and officials during the sydney 2000 and athens 2004 olympic games 0 10 20 30 40 50 60 70 80 90 consutation rate athletes consultations officials consultations sydney 2000 athens 2004 fig. 1. average daily consultation rate and relative percentage of total consultations for athletes and officials during the sydney 2000 and athens 2004 olympic games. fig. 2. percentage of consultations due to injury or various medical complaints during the sydney 2000 and athens 2004 olympic games. 0 5 10 15 20 25 30 chronic injury acute injury other opthalmological renal dermatology psychiatric gynae/urological ear nose throat neurological cardiovascular respiratory gastrointestinal percentage of consultations (%) athens 2004 sydney 2000 fig. 2. percentage of consultations due to injury or various medical complaints during the sydney 2000 and athens 2004 olympic games. profile of medical.indd 73 10/17/08 11:24:15 am athens 2004, detailing acute and chronic injury and the anatomical distribution of the complaint are listed in tables i and ii. the detailed data for these injuries from sydney 2000 have been published in a previous edition of this journal. 2 skeletal muscle strain injuries and ligamentous sprain injuries accounted for 29% and 26% of all acute injuries, while contusion injuries constituted 29% of all acute injuries (table i). lacerations and abrasion injuries accounted for the remainder of the acute injuries. the most common anatomical areas injured acutely were foot and ankle (25%), knee (17%) and upper leg (17%). lumbar spine injuries and upper limb injuries constituted 9% of acute injuries each. altogether 77% of the acute injuries were classified as grade i injuries, 17% grade ii and 6% were grade iii injuries. chronic injuries evaluated during athens 2004 are described in table ii. muscle and ligamentous injuries accounted for 32% and 37% of the chronic injuries respectively, with tendon and bony injuries accounting for 15.5% of the injuries each. the most common anatomical sites injured were foot and ankle (32%), lumbar spine (32%) and shoulder (11%) while the other anatomical regions listed accounted for the remaining 25% of injuries. discussion with the exception of south african athletes living and training overseas, the vast majority of the athletes who travelled to athens for the olympic games were examined during regional evaluations, and at the two pre-olympic camps by the travelling team physicians. this allowed the team and the athletes to become familiar with each other before leaving to compete internationally. this also provided the south african athletes with opportunity for timeous medical intervention and identification, diagnosis and rehabilitation of underlying injury. dietary and psychological evaluations as well as dental evaluations (and interventions if necessary), were also provided for the athletes as part of the preparation programme, particularly as dental problems have been shown to be common in this group of individuals. 9 medical records that were established during the preparation phase formed the base documentation records to be used in the team south africa medical facility in athens. the first important finding of this study was that there were on average 6 formal medical consultations per day during the olympic games in athens. this figure contrasts with that of sydney 2000, 74 sajsm vol 20 no. 3 2008 table i. acute injury by anatomical region during athens 2004 olympic games muscle strain ligament sprain tendon injury contusion laceration abrasion total % head & neck 0 0 0 0 2 0 2 6 lumbar spine 3 0 0 0 0 0 3 9 hip & pelvis 1 0 0 0 0 0 1 3 shoulder 1 0 0 0 0 0 1 3 upper limb 0 0 0 1 1 1 3 9 wrist & hand 0 0 0 2 0 0 2 6 upper leg 4 0 0 2 0 0 6 17 lower leg 1 0 0 0 1 0 2 6 knee 0 4 0 2 0 0 6 17 foot & ankle 0 5 0 3 1 0 9 25 total 10 9 0 10 5 1 35 % 29 26 0 29 14 3 table ii. chronic injury by anatomical region sustained during the athens 2004 olympic games muscle injury ligament injury tendon injury bony injury total % head & neck 0 0 0 0 0 0 lumbar spine 3 3 0 0 6 32 hip & pelvis 1 0 0 0 1 5 shoulder 0 0 2 0 2 11 upper limb 1 0 0 0 1 5 wrist & hand 0 0 0 0 0 0 upper leg 1 0 0 0 1 5 lower leg 0 0 0 1 1 5 knee 0 0 1 0 1 5 foot & ankle 0 4 0 2 6 32 total 6 7 3 3 19 % 32 37 16 16 profile of medical.indd 74 10/17/08 11:24:16 am untitled-1 1 4/18/08 11:20:07 am where the consultation rate was 13 per day. indeed, during athens 2004 only 180 formal medical consultations were conducted compared with 348 consultations over a similar period during sydney 2000. although it is possible that there might have been more ‘informal’ consultations that occurred field-side, pool-side and track-side, it is not possible to keep accurate records of all of these encounters. it is also possible that improved preparation and recovery strategies adopted by the athletes or improved screening and injury management might have accounted for the difference in consultation rate. yet, it is also of interest to note the differences in the profile of consultations depicted in fig. 2. during sydney 2000, many more consultations were conducted due to respiratory and ent complaints, probably as a result of increased aero-allergens and subsequent symptoms associated with allergy, during spring time in australia. 3,5 furthermore, during sydney 2000 there were many more consultations in the first week of travel due to vague neurological complaints (symptoms of headache, malaise, insomnia), probably due to jet lag as a result of travel across many time zones. 7 although ent-related complaints were among the most common encountered in athens, the number of consultations was lower compared with sydney 2000, due to different environmental conditions and improved identification and preparation of susceptible athletes. 3 furthermore, as travel to athens did not involve crossing of many time zones, the team did not experience jet lag, which possibly explains the lower number of neurological complaints. the relative increase in consultations due to dermatological complaints was due to infection or allergic response secondary to ant and other insect bites, in and around the athens olympic village and fungal skin infections, probably as a result of the excessive heat and humidity that occurred in athens at that time. the second important finding of this study is that, as was the case in sydney 2000, the majority of consultations were not due to injury. although 40% of all consultations were due to sports injury, there were more consultations due to injuries in athens than in sydney. indeed, relatively more of the injuries sustained in athens 2004 were acute rather than chronic in nature, due to the fact that both men and women’s hockey teams competed in athens, while only the women’s team competed in sydney 2000. the anatomical distribution of these injuries at the two events was similar, and fortunately the vast majority of these injuries were of minor severity. the profile of the injuries and medical complaints described above is similar and comparable with those reported by the medical teams of other countries. 1,4,10 assessment of the injury and medical statistics allows for good future planning when considering the composition of a medical team for a multi-coded sporting event. it is clear that environmental conditions including airborne allergens, heat and humidity, travel across time zones and even insects in the immediate environment affect the profile of medical consultations during travel to sporting competition. it will be of interest to note the profile of consultations during the olympic games in beijing 2008, where many of the abovementioned factors as well as high concentrations of air pollution were experienced. 6,8 due to the profile of consultations depicted in fig. 2, team physicians should ideally have adequate experience with respect to both injury diagnosis and management and general sports medicine. indeed, good skills with respect to ent, respiratory, neurological and dermatological aspects of sports medicine are important. with respect to sports injuries, knowledge and skills in the management of musculo-skeletal (mostly soft-tissue) injury, particularly of the foot and ankle, lumbar spine and knee regions are important. in conclusion, this study describes the medical care provided to the athletes and officials of the south african team to the olympic games in athens 2004. injury and illness complaints were fewer compared with those documented during sydney 2000, probably due to local environmental conditions and travel across time zones. the analysis of the nature of consultations suggests that it should be a prerequisite for team physicians to have broad knowledge of both medical and injury management of athletes in order to accompany sports teams to multi-coded events. furthermore, a sound knowledge of the management of soft-tissue injury, particularly in the foot and ankle, lumbar spine and knee regions, is an important prerequisite for the personnel of the medical team. acknowledgements the author would like to thank dr christa janse van rensburg, dr harald adams and dr maki ramagole for their support and effort in collection of the data used in this study. references 1. budgett r, harries m, aldridge j, jaques r, jennings de. lessons learnt at the 1996 atlanta olympic games. br j sports med 1997; 31: 76. 2. derman we. medical care of the south african olympic team -the sydney 2000 experience. south african journal of sports medicine 2003; 15: 22-5. 3. hawarden d, baker s, toerien a, et al. aero-allergy in south african olympic athletes. s afr med j 2002; 92: 355-6. 4. junge a, langevoort g, pipe a, et al. injuries in team sport tournaments during the 2004 olympic games. am j sports med 2006; 34: 565-76. 5. katelaris ch, carrozzi fm, burke tv, byth k. patterns of allergic reactivity and disease in olympic athletes. clin j sport med 2006; 16: 401-5. 6. li j, lu y, huang k, et al. chinese response to allergy and asthma in olympic athletes. allergy 2008 ;63: 962-8. 7. milne cj, fuard mh. beating jet lag. br j sports med 2007; 41: 401. 8. milne cj, shaw mt. travelling to china for the beijing 2008 olympic games. br j sports med 2008; 42: 321-6. 9. piccininni pm, fasel r. sports dentistry and the olympic games. j calif dent assoc 2005; 33: 471-83. 10. robinson d, milne c. medicine at the 2000 sydney olympic games: the new zealand health team. br j sports med 2002; 36: 229. 76 sajsm vol 20 no. 3 2008 profile of medical.indd 76 10/17/08 11:24:17 am 42 sajsm vol 22 no. 2 2010 introduction the purpose of this paper is to make an informed forecast of how south africa will perform at the 2010 commonwealth games to be held in delhi, india, between 3 and 14 october. the forecast is expressed in terms of the number of gold medals and total medals that south african athletes can expect to win at delhi 2010. forecasting performance in elite sports competitions is not a new phenomenon. traditionally, prediction models have tended to focus almost exclusively on the olympic games.1-5 more recent studies have sought to predict the performance of nations that previously hosted, or are scheduled to host, the summer olympic games.3-5 in this context, this paper provides a departure from normal convention by attempting to forecast how a nation will perform away from home in the commonwealth games. methods the approach used to forecast south africa’s performance in delhi in 2010 was to examine and interpret the nation’s results in previous editions of the commonwealth games. the historical results for south africa were collated from the commonwealth games federation website (http://www.thecgf.com, last accessed 15 march 2010). the data were formatted in a spreadsheet and analysed to develop three potential scenarios, as illustrated below. scenario 1 models south africa’s likely performance in 2010 on a sport-by-sport basis in accordance with the proportion of medals it achieved in the most recent edition of the commonwealth games (melbourne 2006), while allowing for a change in the number of events that will be contested in each sport in delhi. in scenario 2 we calculate how many medals south africa will win in delhi if its performance in each sport follows the same pattern of growth since south africa rejoined the commonwealth in 1994. since then there have been four editions of the commonwealth games, even though the analysis focuses on the last three editions (1998 2006) because some of the sports to be contested in delhi were not introduced to the commonwealth games programme until 1998. recent research6 indicates that, as a general rule of thumb, a nation’s performance in the commonwealth games is negatively correlated with travel (as measured by the number of time zones crossed). in other words, as distance travelled increases, performance deteriorates. therefore, scenario 3 considers south africa’s performance since 1998 with regard to how many time zones its athletes had to traverse to reach the host destination. for sports where travel was found to have a detrimental impact on the performance of south african athletes, the forecast was adjusted to model the potential outcome of the commonwealth games being held in india (time zone: utc + 05:30). results the results for each scenario are summarised in table i. scenario 1. in this scenario, south africa can expect to win 12 gold medals and 40 medals in total at delhi 2010. in absolute terms, south africa will win the same number of gold medals as in melbourne in 2006, but will win two extra medals overall. this reflects the fact that more events will be contested at delhi 2010 (257) than at melbourne 2006 (245); however, in 2010 there are 11 fewer events in the two sports in which south africa enjoyed the most success in 2006 – athletics and swimming. collectively, these sports accounted for 83% (10/12) of gold medals and 68% (26/38) of all medals won by south africa at melbourne 2006. forecasting south africa’s performance at the 2010 commonwealth games abstract objectives. this paper predicts south africa’s performance at the delhi 2010 commonwealth games. methods. potential scenarios are developed based on south africa’s previous performances. results. south africa will win up to 15 gold medals and 43 medals in total. conclusions. after delhi 2010, the actual results should be examined to verify the forecasts. correspondence: girish m ramchandani sport industry research centre sheffield hallam university a118 collegiate hall collegiate crescent sheffield s10 2bp uk tel: +44 (0) 114 225 5461 e-mail: g.ramchandani@shu.ac.uk girish m ramchandani (msc) darryl j wilson (msc) sport industry research centre, sheffield hallam university, sheffield, uk commentary sajsm vol 22 no. 2 2010 43 scenario 2. by regressing south africa’s performance (medals won divided by medals available) in the commonwealth games over time (1998 2006) and extrapolating to 2010, the forecast for delhi is 14 gold medals and 42 total medals. the scenario 2 forecast is more favourable than the scenario 1 forecast, largely because south africa’s performance in swimming has been on an upward trend since 1998. scenario 3. if we factor in the relative influence of travel on performance then south africa can be expected to win 15 gold medals and 43 medals overall at delhi 2010, despite fewer numbers of medals available in key sports. therefore, this scenario offers the most optimistic view of anticipated performance. gains are likely to be made in lawn bowls, shooting and rugby sevens. conclusions the quality of any forecasting model is only as good as the assumptions that underpin it. in this paper, we have considered three different scenarios to model how many medals south africa will win at the delhi 2010 commonwealth games based on its performance in recent editions. the analysis reveals that south africa can expect to win 12 15 gold medals and 40 43 medals in total. the scenarios offer distinct forecasts of how south africa will perform in delhi, but broadly agree on the number of medals it can be expected to win. it would be worthwhile to scrutinise the actual performance of south african athletes in delhi to test the accuracy of the forecasts presented in this paper. references 1. bernard a, busse m. who wins the olympic games? economic resources and medal totals. review of economics and statistics 2004; 6(1):413417. 2. bian x. predicting olympic medal counts: the effects of economic development on olympic performance. the park place economist 2005;xiii:37-44. 3. clarke sr. home advantage in the olympic games. in: cohen g, lantrey t, eds. proceedings of the fifth australian conference on mathematics and computers in sport. sydney, nsw: university of technology sydney, 2000:43-51. 4. shibli s, bingham j. a forecast of the performance of china in the beijing olympic games 2008 and the underlying performance management issues. managing leisure 2008;13:272-292. 5. nevill am, balmer nj, winter em. why great britain’s success in beijing could have been anticipated and why it should continue beyond 2012. br j sports med 2009;43:1108-1110. 6. ramchandani g, wilson d. home advantage in the commonwealth games south african journal of sports medicine 2010;22:8-11. table i. forecasts of south africa’s performance at delhi 2010 delhi 2010 medals available sa forecast – scenario 1 sa forecast – scenario 2 sa forecast – scenario 3 sport gold medals total medals gold medals total medals gold medals total medals gold medals total medals athletics 46 138 4 12 5 11 5 11 badminton 6 18 boxing 10 40 1 2 1 3 1 2 cycling 18 54 1 diving 10 30 gymnastics 20 60 1 hockey 2 6 lawn bowls 6 18 2 1 1 3 netball 1 3 rugby 7s 1 3 1 shooting 36 108 1 5 4 9 squash 5 15 swimming 40 120 5 11 7 17 7 11 table tennis 7 21 weightlifting 15 45 1 1 1 wrestling * 21 63 3 3 3 subtotal 244 742 11 38 13 40 14 41 other† 13 39 1 2 1 2 1 2 total 257 781 12 40 14 42 15 43 *the forecast for wrestling is based on south africa’s performance at the 2002 commonwealth games (manchester) because wrestling was not part of the programme in 2006 and 1998. † includes archery and tennis, for which no recent relevant performance data are available. archery was held only once in 1982 and tennis will make its debut at delhi 2010. the forecasts for these sports are made proportionately according to the ratio of gold medals and total medals that south africa can expect to win in the conventional sports. pg84-86.indd summary paget-schroetter syndrome or effort thrombosis is a rare condition with potentially severe consequences, affecting young and otherwise healthy athletes. its classic clinical presentation should be rapidly identified to promote early diagnosis and treatment. this prevents recurrences and long-term complications such as persistent swelling of the affected arm. in a 1-year period we saw two young male athletes with this condition. one was treated conservatively and the other surgically, with vastly different outcomes. we therefore present their cases as well as a review of relevant literature to emphasise treatment of this rare condition. case 1 a 23-year-old male professional road cyclist presented 2 days after an acute onset of swelling of the right arm. he had been given a new bicycle by his sponsor, and had gone for a 4-hour cycle. his position on the new bike was slightly different to his previous cycling position, with the handlebars being slightly closer to his body, and he noticed swelling and heaviness of his right arm the following day. on examination, his right arm was markedly swollen from the axilla to the fingers, with the biceps diameter being 30 cm on the right compared with 27 cm on the left. he had normal pulses and no adverse neurological findings. a duplex doppler of the arm revealed no thrombus formation, and the veins were reported as having normal compressibility. a venogram was then conducted, which showed a deep vein thrombosis (dvt) of the right subclavian vein, related to the medial third of the clavicle and first rib with early collateral formation. risk factors for thrombus formation include a malignant melanoma which had been excised 13 years previously, a high haematocrit (49.4%), the cyclist’s posture, and the new cycling position adopted on the new bicycle. blood investigations included a thrombotic work-up, which was completely normal. his x-rays of chest and cervical spine were both normal. there was no evidence of recurrence of the melanoma. treatment with anticoagulation was initiated within 2 days of his initial presentation. he was offered thrombolysis of the clot, but refused this treatment. thrombolysis is usually performed by insertion of a percutaneous catheter, and a haemolytic agent is infiltrated directly into the site of the clot. the procedure is usually performed at the same time as the venogram, as the same catheter may be used for both procedures. when his swelling persisted beyond 7 days he requested further intervention, and was offered surgical excision of the affected vein with first rib resection to decompress the thoracic outlet. his surgery was performed 2 weeks after the initial presentation, and included the above-mentioned treatment and a saphenous vein graft to anastamose the subclavian vein. unfortunately, several intraoperative complications were encountered including a laceration of the pleura, haemothorax, on-table severe bradycardia presumed to be caused by a pulmonary embolus and requiring resuscitation, and severing of the phrenic nerve. the patient managed to overcome these complications, continued anticoagulant therapy for 6 months, and then attempted unsuccessfully to return to professional cycling. he was followed up a year later, and found to have no residual swelling of the arm. case 2 case 2 was a 25-year-old amateur rugby prop forward. he described a tearing sound in his left shoulder, which occurred when he performed a spear tackle (an action that he described as being similar to a dead-lift in weight lifting) on another player. he presented 2 weeks later in the consulting rooms with marked swelling and heaviness of his right arm. the diameters of his arms at biceps level were 47 cm and 42 cm respectively. the pulses of his right arm felt weak due to the swelling of the arm, and he had no neurological deficit in the arm. he was markedly tender to palpation and swollen over the right coracoid process. the initial doppler of his subclavian and axillary vein showed no abnormality, but when it was repeated by an experienced vascular surgeon, it showed a dvt at the junction of the subclavian and jugular veins on the right side. anticoagulant therapy and a pressure stocking of the arm were initiated at his first visit. he was offered thrombolysis, but he too refused the treatment. he was treated with physical therapy for a torn pectoralis minor muscle that case study effort thrombosis: a case study and discussion correspondence: dr robert matthew collins university of pretoria, section sports medicine po box 11 mondeor 2110 johannesburg tel: +27 11 680 5684 fax: +27 86 516 7975 e-mail: robcollins@wol.co.za robert matthew collins (mb bch, msc sports med))1 dina christina janse van rensburg (mmed (physmed) (rheumatology), msc (sports med), mb chb)1 catherina cornelia grant (bsc, bsc hon (physiology), msc (physiology))1 jonathan speridon patricios (mb bch, mmed (sci), facsm, ffsem (uk))1 martin veller (mmed (surg), fcs(sa))2 dimakatso althea ramagole (mb chb, msc sports med))1 1 section sports medicine, university of pretoria 2 university of the witwatersrand, johannesburg 84 sajsm vol 22 no. 4 2010 sajsm vol 22 no. 4 2010 85 was thought to have caused the thrombosis, and postural correction. at 3-month follow-up he had no residual swelling of his arm, and was scheduled to undergo positional venography to assess the patency of the subclavian vein and exclude thoracic outlet compression of the vein when he was lost to follow-up. he has since been contacted, is completely symptom free, and has no recurrent swelling of his arm at all. discussion dvt is a common condition, but only 2 4% of all dvts involve the upper limb. 1-6 primary subclavian vein thrombosis is a relatively uncommon condition, affecting 2/100 000 people per year, which represents 15 24% of all upper limb dvts, 7,8 but it is the most common vascular disorder affecting professional, collegiate or highschool athletes. 5,7,9 it was first described by sir james paget in 1858, and later by leold van schroetter in 1884. the english surgeon, hughes, gave it the eponym paget-schroetter syndrome (pss) when he reviewed 320 cases from literature in 1949. 2,3,5-8,10,11 another synonym for the condition in literature is ‘effort thrombosis’, which emphasises the causal relationship between certain forms of exercise and thrombosis of the subclavian vein. 4,6 this relationship was first identified by von schroetter in 1899. 2,8 pss occurs primarily in young, otherwise healthy subjects (mean age 15 30 years) who participate in repetitive upper limb activities. 3,4,7-10 it occurs twice as frequently in men as in women, affecting the right or dominant arm in 80% of cases. 1,2,5,6,8 it has been reported in many sports, including golf, american football, weight lifting, baseball, wrestling, tennis, martial arts, backpacking, billiards, swimming, rowing and cheerleading. 1-3,10 because of the youth and otherwise healthy state of those presenting with this condition, it is often ignored or misdiagnosed. 8 in a series of eight patients with the condition, zell et al. found that five of the eight patients were untrained athletes for whom exercise was not the norm. 2 the mechanism of thrombosis is through a thoracic outlet compression and/or repetitive intimal strain of the axillary or subclavian vein by retroversion and hyperabduction of the arm. 7,9 repetitive intimal strain can lead to inflammation and traumatic fissures in the intima of the vein, resulting ultimately in thrombus formation. 2,4,6,10,11 compression of the vein in the thoracic outlet through lateral abduction of the arm or hypertrophy of subclavian or anterior scalene muscles can cause turbulence in the vein, which is exacerbated by increased venous flow experienced during exercise. 2,10 thrombosis occurs most commonly at the level of the subclavian vein where it crosses the thoracic outlet and may be compressed. 4 lifting of heavy weights can also cause compression of the vein in the thoracic outlet by depression of the shoulder, causing compression of the vein between the clavicle and first rib. 8,10 the occurrence of pss can also be contributed to by a hypercoagulable state 10 and upper limb thromboses are more frequently associated with underlying malignant disorders than those in the lower limb. 11 melby et al. stated that the chronic repetitive compression and intimal micro-trauma that result in pss make it an acute manifestation of a chronic condition rather than a single traumatic event. 9 this observation is important in the management of the condition, as it is essential to treat the causative pathology to prevent recurrence. 9 pss should be distinguished aetiologically from other subclavian dvts, which are caused by primary diseases and other known risk factors such as malignant neoplasms, treatment with central venous catheters or pacemakers, or cervical ribs. 2 these patients develop secondary thrombosis, and are older, and have concurrent systemic illness. 3 the anatomical relations of the subclavian vein in the thoracic outlet are: • superior and anterior: the clavicle, subclavius muscle and costoclavicular ligament • inferior: first rib • posterior: anterior scalene muscle. 1,3,8 other structures which are in close relation to the subclavian vein in and around the thoracic outlet include: pectoralis minor and supraspinatus muscles, coracocostal ligament, osseous exostoses, cervical ribs, fibrous cords. 3,8 cervical ribs are present in between 0.5% and 1% of the general population, but cause symptoms in less than 10% of these people, most of whom have arterial or neurological thoracic outlet syndromes. 3 patients present with symptoms of venous obstruction of the arm including a dull aching pain, non-oedematous swelling, a feeling of heaviness in the arm, and bluish discolouration of the arm. 6-8,10 symptoms range in severity, may be position-dependent, and occasionally the patient may be asymptomatic. 7,8 differential diagnosis includes: • fracture of the mid-shaft of the humerus • soft-tissue injury or infection with compartment syndrome • muscular strain or sprain resulting in local tenderness and swelling. 6 pulmonary thrombo-embolism is a rare complication of pss, and occurs in between 7% and 20% of cases. 3-5,7 early and accurate diagnosis is of paramount importance to prevent long-term complications and recurrence. 2,3 it has been stated that with pss the earlier the diagnosis and treatment, the better the outcome. 11 duplex doppler is the first diagnostic test of choice, as it is non-invasive, and is reported as having a high sensitivity and specificity for peripheral dvt. 7 melby et al., however, reported a relatively low diagnostic sensitivity of 71% of duplex doppler to upper extremity thrombosis, 9 and shebel states that it is only reliable for thrombus extending into the axillary vein. 8 they stated that this is as a result of technical difficulties in visualising the subclavian vein below the clavicle, especially in the presence of extensive collateral veins, and the inability to compress the vein within the thoracic outlet. 8,9 they therefore suggested that a negative duplex doppler should not exclude thrombosis, and that contrast venography should be the diagnostic test of choice. 1,6,8,9 positional venography with the arm in neutral, abducted and externally rotated positions, is also of value in not only assessing costoclavicular compression of the subclavian vein, but also compression of collateral veins with positional changes of the arm. 8 there is no consensus on the optimal treatment of pss, as most published data consist of individual case reports and small series. 3,5,11 hiken and ameli conducted a literature review to determine the most appropriate treatment for pss, and concluded that since treatments, follow-up and conclusions reported were so varied, optimal treatment remains controversial. 12 traditional treatment consists of anticoagulation and elevation of the limb to facilitate thrombus resolution, and prevent further thrombus formation. 3,7 there are varying reports of the incidence of post-thrombotic syndrome (pts), which is characterised by chronic swelling and heaviness of the arm and hand. incidences of pts of between 41% and 73% 3-6,11 with conservative treatment have been reported, with severity of symptoms ranging vastly. historically most authors have concluded, in the light of these varying data, that non-operative treatment of axillary thrombosis provided a predictably good outcome, and that surgical intervention was not warranted. 3 despite these conclusions, there was persistent concern over residual symptoms following pss treated with anticoagulation therapy alone, which ‘rarely produces symptom-free use of the arm, and imposes limitations that appear unacceptable to most patients’. 9 this led to the advent of catheter-directed thrombolysis, which is currently regarded as the initial treatment of choice, 5 as a treatment. 3,10 as mentioned previously, this involves injection of a thrombolytic agent into the site of the thrombus via a percutaneous catheter. the procedure is often performed at the time of venography, as the same catheter can be used for both procedures. the advantage of early thrombolysis is that it restores venous patency, thus minimising the damage to the endothelium, and reducing the risk of post-thrombotic syndrome. 3,7 venous patency is accepted as the main factor in preventing residual symptoms. 3 this has been shown to be achieved through thrombolysis alone if the treatment is initiated within 1 week of the onset of symptoms. 5,6,13 fibrinolysis alone is unsuccessful in nearly 20% of patients even when undertaken within a week of onset of symptoms. 5 there is a greater incidence of fibrous stricture formations at the site of the thrombus if thrombolysis occurs beyond 1 week. in these cases, further surgical intervention such as vein patch angioplasty and decompression of the thoracic outlet is indicated. 13 other methods of overcoming strictures have been tried, including balloon angioplasty and the placement of stents. balloon angioplasty is usually unsuccessful due to extrinsic compression of the subclavian vein and dense perivenous scar tissue, which results in immediate recoil or re-stenosis. 5,9 endoluminal stents are similarly an ineffective treatment, as subclavian vein compression frequently results in bending or fracture of the stent with subsequent re-thrombosis. 5,9 defining whether or not the patient has a pre-existing anatomical anomaly is essential in determining which patients will benefit from surgical decompression of the thoracic outlet, as pss cannot be effectively treated without addressing compressive mechanisms causing thrombogenesis. 5,7 if extrinsic venous compression is identified, many surgeons advocate early decompression of the thoracic outlet via resection of the first rib or clavicle. others, however, recommend a trial of conservative therapy after thrombolysis. 7 hicken et al. stated that surgical intervention should be reserved for patients in whom there is a specific indication. 12 in a series of 32 cases of pss treated between january 1997 and january 2007, melby et al. showed excellent results to surgical intervention. 9 they offered surgical treatment to all patients. their treatment included thoracic outlet decompression via complete anterior and middle scalenectomy, brachial plexus neurolysis, excision of subclavius muscle tendon, and resection of the first rib. they also performed external venolysis of the subclavian vein on all patients, excising all scar tissue from the axillary vein to the subclavianjugular-innominate vein junction. they were able to demonstrate normal compressibility of the vein through palpation or intraoperative venography in 56% of the patients. these patients had no further venous reconstruction. the remaining 44% had residual narrowing of the subclavian vein in at least one portion. the affected section of the vein was resected, and reconstructed using an autologous saphenous vein patch. in 59% of the patients they also created a radiocephalic arteriovenous fistula, which assisted in maintaining flow through the grafted area. 9 the median time to full return to competitive sport in their series was 3.5 months from the time of surgery (range 2 10 months), with 50% of the patients resuming sports participation by 3 months. 9 they found that there was no difference in time to return to sporting activities after operative intervention in patients with delayed diagnosis or recurrent symptoms. 9 conclusion pss is a rare condition, but the most common vascular condition affecting athletes. it may present with subtle symptoms, but early diagnosis is imperative in being able to initiate early treatment. duplex doppler, although the first diagnostic test of choice, is unable to always definitively exclude the condition, and venography is recommended if there is clinical suspicion and a negative doppler test. anticoagulation is important to prevent thrombus proliferation, but is often unsuccessful as a sole treatment for pss. thrombolysis is often successful in restoring venous patency and preventing longterm sequelae of post-thrombotic syndrome if performed within 7 days of the onset of the condition. surgical intervention may be required to restore venous patency and compressibility and to relieve external compression of the vein in the thoracic outlet. these can be assessed through positional venography in the patient who has completely symptomatically recovered with conservative treatment. failure to achieve complete recovery with conservative treatment alone is an indication for further intervention. surgical options include external venolysis, resection of affected segments of vein with saphenous vein patching, and thoracic outlet decompression via first rib resection or scalene or subclavian muscle resection. references 1. toya n, fujita t, ohki t. push-up exercise induced thrombosis of the subclavian vein in a young woman: report of a case. surg today 2007;37(12):1093-1095. 2. zell l, kindermann w, marschall f, scheffler p, gross j, buchter a. pagetschroetter syndrome in sports activities--case study and literature review. angiology 2001;52(5):337-342. 3. difelice gs, paletta ga,jr, phillips bb, wright rw. effort thrombosis in the elite throwing athlete. am j sports med 2002;30(5):708-712. 4. meier ma, rubenfire m. life-threatening acute and chronic thromboembolic pulmonary hypertension and subclavian vein thrombosis. clin cardiol 2006;29(3):103-106. 5. feugier p, aleksic i, salari r, durand x, chevalier jm. long-term results of venous revascularization for paget-schroetter syndrome in athletes. ann vasc surg 2001;15(2):212-218. 6. chaudhry ma, hajarnavis j. paget-von schrotter syndrome: primary subclavian-axillary vein thrombosis in sport activities. clin j sport med 2003;13(4):269-271. 7. roche-nagle g, ryan r, barry m, brophy d. effort thrombosis of the upper extremity in a young sportsman: paget-schroetter syndrome. br j sports med 2007;41(8):540-541. 8. shebel nd, marin a. effort thrombosis (paget-schroetter syndrome) in active young adults: current concepts in diagnosis and treatment. j vascular nursing 2006;24(4):116-126. 9. melby sj, vedantham s, narra vr, et al. comprehensive surgical management of the competitive athlete with effort thrombosis of the subclavian vein (paget-schroetter syndrome). j vasc surg 2008;47(4):809-820. 10. mcglinchey pg, shamsuddin sa, kidney jc. effort-induced thrombosis of the subclavian vein--a case of paget-schroetter syndrome. ulster med j 2004;73(1):45-46. 11. oktar gl, ergul eg. paget-schroetter syndrome. hong kong med j 2007;13(3):243-245. 12. hicken gj, ameli fm. management of subclavian-axillary vein thrombosis: a review. canad j surg 1998;41(1):13-25. 13. molina je. need for emergency treatment in subclavian vein effort thrombosis. j am coll surg 1995;181(5):414-420. 86 sajsm vol 22 no. 4 2010 introduction long-term injury surveillance has been carried out in australia, south africa and england to identify injury patterns. retrospective injury information was obtained from 54 cricketers who had played for the same county first team in england between 1985 and 1995, with 990 injuries indicating an injury exposure of 17 247 days played and an injury incidence rate of 57/1 000 days played.1 most injuries were sustained early in the season. bowlers were most susceptible to injury (70/1 000 days), followed by all-rounders, batsmen and wicketkeepers with 55, 49 and 47 injuries per 1 000 days, respectively. most injuries occurred to the lower limbs (45%), with muscle/tendon strains, contusions/haematomas, and ligament/joint sprains being the most common. the most vulnerable sites for injury were the thigh and calf (25%), fingers (14%) and lumbar spine (11%). the study in south africa2 prospectively recorded 1 606 injuries in 783 national and provincial cricketers over a six-season period from 1998 1999 to 2003 2004. more injuries occurred during first-class matches (32%), with limited-overs matches (26%) and practices and training (27%) resulting in a similar number of injuries, while 15% were of gradual onset. the chronicity of injuries showed that the majority were classified as acute (65%), with chronic (23%) and acute-on-chronic (12%) comprising the balance. first-time injuries accounted for 65%, while the balance of injuries were from the previous season (22%) and from those recurring again during the same season (12%). bowling (40%) accounted for the majority of injuries, with 55% of these being lower-limb injuries and 33% back and trunk injuries. of the 39 stress fractures, 79% were as a result of overuse in bowlers. the primary mechanism of injury was the delivery and follow-through of the fast bowler (25%), running, diving, catching and throwing the ball when fielding (23%), overuse (17%), original research article injury patterns of south african provincial cricket players over two seasons abstract objective. to determine the incidence and nature of injury patterns in elite cricketers over two seasons. methods. physiotherapists and/or doctors working with 4 provincial teams completed a questionnaire for each cricketer who presented with an injury during the 2004 2005 (s1) and 2005 2006 (s2) cricket seasons. this was done to determine: (i) the anatomical site of injury; (ii) the month of injury during the season; (iii) the diagnosis using the oscis injury classification system; (iv) the mechanism of injury; (v) whether it was a recurrence of a previous injury; (vi) whether the injury had recurred again during the season; and (vii) biographical data. results. the results showed that 180 injuries (s1 – 84; s2 – 96) were sustained. on average the teams spent 2 472 hours on matches, 4 148 on practices and 1 612 on fitness training during the two-season period. the injury prevalence was 8% per match, while the injury incidence was 30/10 000 hours of match, practice and training time, with the match incidence being 74 injuries/ 10 000 hours and the training incidence 15 injuries/10 000 hours. bowling (29%), fielding and wicket-keeping (27%) and batting (19%) accounted for the majority of injuries. the occurrence of injuries was predominantly to the lower limbs (s1 – 45%; s2 – 42%), back and trunk (s1 – 19%; s2 – 19%), upper limbs (s1 – 19%; s2 – 22%), head and neck (s1 – 6%; s2 – 3%), and related to illnesses (s1 – 11%; s2 – 14%). the injuries occurred primarily during first-class matches (39%), limited-overs matches (22%), and practices (17%), and some were of gradual onset (20%). acute injuries comprised 78% of injuries. the majority of injuries were first-time injuries (76%), with 11% and 14% recurrent injuries from the previous and current seasons, respectively. the correspondence: dr richard stretch nelson mandela metropolitan university po box 77000 port elizabeth, 6031 south africa e-mail: richard.stretch@nmmu.ac.za richard a stretch (dphil)1 ryan p raffan (ba, hms hons)2 nicole allan (ba, hms hons)2 1sport bureau, nelson mandela metropolitan university, port elizabeth 2department of human movement science, nelson mandela metropolitan university, port elizabeth sajsm vol 21 no. 4 2009 151 major injuries during s1 were haematomas (19%), muscle strains (17%) and other trauma (14%), while during s2 the injuries were primarily muscle strains (16%), other trauma (20%), tendinopathy (16%) and acute sprains (15%). the primary mechanisms of injury occurred in the delivery stride when bowling (19%) and overbowling (7%), on impact by the ball when batting (11%), and on sliding to field the ball (6%). conclusion. the results indicate a pattern of cause of injury, with the fast bowler most likely to sustain an acute injury to the soft tissues of the lower limb while participating in matches and practices during the early part of the season. various batting situations such as being struck while batting (7%), running between the wickets (4%), batting for long periods at a time (4%), training (4%), and participating in various other sports (3%). injury data of australian state and national cricketers were collected retrospectively for the first three seasons (1995 1996 to 1997 1998) and then prospectively for the next six seasons (1999 2000 to 2004 2005).3 of the 886 injuries recorded, 92% were new, 8% were recurrent, and 52% occurred during major matches. the injuries were mainly sustained while bowling (45%), with lowerlimb injuries accounting for 49%. the mean seasonal injury match incidence was reported for domestic one-day (39/10 000 playerhours), first-class (27/10 000 player-hours), one-day international (odi) (60/10 000 player-hours) and test (39/10 000 player-hours) matches. fast bowlers miss about 16% of potential playing time because of injury, while for other positions it is less than 5%. the first study to use the international surveillance method4 reported that 162 domestic and 33 international cricketers sustained 50 injuries. most injuries were sustained in test and first-class matches (40%), with a further 28% occurring during one-day matches and other activities outside of matches. the injury incidence for tests and odi matches was 49 and 41 injuries/10 000 player-hours, respectively. for domestic first-class and limited-overs matches it was 14 and 25 injuries/10 000 player-hours, respectively. the injury prevalence for test (11%) and odi (8%) matches was lower for home matches than away matches. bowlers (46%) and batsmen (40%) were at greatest risk of injury, with muscles (26%) and ligament (12%) injuries, stress fractures (12%) and fractures (10%) being most common. most of the injuries were new (80%), with 10% recurrent from the previous season and 10% recurring again during the same season. all the injury surveillance studies, with the exception of the study carried out on west indian cricketers,4 were carried out before the international acceptance of the publication of the consensus paper regarding injury definitions, methods of calculating injury rates and reporting of injuries.2 therefore, the aim of this study was to use the internationally agreed methods for injury surveillance to investigate the seasonal incidence and nature of injuries sustained by south african provincial cricketers to further understand and identify injury patterns, risk factors and other possible factors associated with these injuries. methods during the 2004 2005 (s1) and 2005 2006 (s2) cricket seasons, matches played by 4 of the 6 provincial teams were monitored prospectively. data were collected and reported according to the guidelines in the consensus paper.5 the physiotherapists working with the teams were required to complete a questionnaire for all cricketers who presented with an injury. the questionnaire was designed to obtain the following information: (i) biographical data; (ii) month of injury during the season; (iii) activity and time of onset of injury; (iv) whether it was a first-time injury or a recurrent injury from the previous or current season; (v) chronicity of the injury; (vi) whether the injury had recurred again during the season; (vii) the oscis6 injury classification code; (viii) diagnosis; and (ix) mechanism of injury. further, to determine player exposure it was necessary to collect information on a player’s participation in each match, reasons for non-participation, and length of the match.2 for the purpose of this research an injury was defined as any injury or other medical condition that either: (i) prevents a player from being fully available for selection for a major match; or (ii) during a major match causes a player to be unable to bat, bowl or keep wicket when required to do so by either the rules or the team’s captain.5 acute injuries were those of rapid onset, and chronic injuries were of prolonged or extended onset, while acute-on-chronic injuries were increased symptoms of a chronic injury but brought about by movements causing rapid onset. the time in the season when the injury occurred was recorded. off-season was defined as that part of the season when no specific cricket practice or training took place. the pre-season, a 2-month 152 sajsm vol 21 no. 4 2009 table i. incidence and prevalence of injuries during the two-season period s1 s2 st matches played first class (n) 30 41 71 45 over (n) 35 44 79 20 over (n) 14 25 39 matches missed (n) 57 158 215 injuries (n) 84 96 180 injury incidence (injuries/10 000 h) match and training 34 27 30 match 89 62 74 training 15 16 15 injury prevalence (%/match) 3 8 8 s1 – 2004 2005 season. s2 – 2005 2006 season. st – 2004 2005 and 2005 2006 seasons. table iii. number of injuries sustained in matches, practices and training during the two-season period s1 s2 st n % n % n % matches 20 over 1 1 7 7 8 4 45 over 13 16 18 19 31 17 first class 42 50 28 29 70 39 practice 14 17 16 17 30 17 gradual onset 12 14 23 24 35 20 training 2 2 4 4 6 3 total 84 100 96 100 180 100 s1 – 2004 2005 season. s2 – 2005 2006 season. st – 2004 2005 and 2005 2006 seasons. percentages have been rounded. table v. diagnosis of injuries sustained during the two season period s1 s2 st n % n % n % haematomas 16 19 6 6 22 12 acute sprains 6 7 14 15 20 11 tendinopathies 4 5 15 16 19 11 muscle strains 14 17 15 16 29 16 trauma 12 14 19 20 31 17 other injuries 32 38 27 28 59 33 total 84 100 96 100 180 100 s1 – 2004 2005 season. s2 – 2005 2006 season. st – 2004 2005 and 2005 2006 seasons. the percentages have been rounded. period, was that part of the season when specific cricket practice and training were undertaken before the commencement of matches. the season was defined as that part of the season when matches were played and included international tours. the bmdp statistical software package (bmdp, 1993, los angeles, bmdp statistical software inc.) was used to compute descriptive statistics. results the 4 provincial teams played a total of 71 first-class, 79 45-over and 39 20-over matches. one hundred and eighty injuries were reported over the two seasons (s1 – 84; s2 – 96), which resulted in players missing 215 matches (table i). the injury incidence for the two seasons for the matches, practices and training was 30/10 000 hours, with the match incidence being 74/10 000 hours and the practice and training incidence being 15/10 000 hours. the injury prevalence increased from s1 (3%) to s2 (8%) (table i). although more injuries occurred in s2 (53%) than s1 (47%), the number of matches missed owing to injuries increased from 57 to 158. first-time and acute injuries comprised 76% and 78% of the injuries to provincial players, respectively. the number of recurring injuries from the previous season increased from s1 (7%) to s2 (14%) and was accompanied by an increase in acute-on-chronic injuries from 12% to 17% (table ii). the injuries occurred primarily during matches (61%), with the balance occurring as a result of gradual onset (20%), practices (17%) and training (3%) (table iii). the regional distribution of injuries indicates that these were mainly to the lower limbs (42%) (table iv). the major injury occurrences in s1 were haematomas (19%), muscle strains (17%) and trauma (14%). similar results were found for s2, with the major injury categories being muscle strains (16%), trauma (20%), tendinopathies (16%) and acute sprains (15%) (table v). the majority of injuries occurred while bowling (33%) in s1, with fielding (25%) and batting (21%) contributing to the remainder of the injuries (table vi). in s2 the injuries were distributed more evenly among fielding (28%), bowling (26%), ‘other’ (26%) and batting (17%). the mechanisms for injuries within each activity are shown in table vi. more injuries occurred during the first half of the season (october december) than in the second half (january march) (table vii). the mean match and practice exposure time increased from s1 (2 096 h) to s2 (2 136 h), while there was a decrease in fitness exposure time from s1 (2 013 h) to s2 (1 714 h) (table viii). team 1 sajsm vol 21 no. 4 2009 153 table ii. chronicity and occurrence of injuries during the two-season period s1 s2 st n % n % n % first time 66 79 70 73 136 76 recurring previous season 6 7 13 14 19 11 current season 12 14 13 14 25 14 acute 68 81 72 75 140 78 chronic 6 7 8 8 14 8 acute-on-chronic 10 12 16 17 26 14 s1 – 2004 2005 season. s2 – 2005 2006 season. st – 2004 2005 and 2005 2006 seasons. table iv. regional distribution of injuries sustained during the two-season period s1 s2 st n % n % n % head and neck 5 6 5 3 upper limb 16 19 24 25 40 22 back and trunk 16 19 18 19 34 19 lower limb 38 45 37 39 75 42 other 9 11 17 18 26 14 total 84 100 96 100 180 100 s1 – 2004 2005 season. s2 – 2005 2006 season. st – 2004 2005 and 2005 2006 seasons. the percentages have been rounded. table vi. role and mechanism of injuries sustained during the two-season period s1 s2 st n % n % n % batting 18 21 16 17 34 19 impact by ball 14 6 20 batting – overuse 4 9 13 other 1 1 bowling 28 33 25 26 53 29 delivery stride 9 2 11 over-bowling 9 4 13 general bowling 6 17 23 other 4 2 6 fielding 21 25 27 28 48 27 sliding for ball 6 5 11 running to field ball 2 4 6 impact by ball 6 2 8 catching a ball 3 3 6 throwing 6 6 other 4 7 11 fitness 2 3 3 3 5 3 touch rugby 1 2 3 other 1 1 2 other 15 18 25 26 40 22 illness 8 18 26 other 7 7 14 total 84 100 96 100 180 100 s1 – 2004 2005 season. s2 – 2005 2006 season. st – 2004 2005 and 2005 2006 seasons. the percentages have been rounded. substantially decreased their fitness exposure time from s1 (2 075 h) to s2 (407 h) and almost doubled their practice exposure time from s1 (3 420 h) to s2 (6 570 h), which contributed to an increase in total exposure time from s1 (7 735 h) to s2 (9 265 h). team 2 increased their fitness exposure time from s1 (3 005 h) to s2 (3 895 h), with a comparable decrease in practice exposure time from s1 (5 825 h) to s2 (5 075 h). the result was similar total exposure time in s1 (11 083 h) and s2 (11 119 h). team 3 had similar fitness exposure time in s1 (960 h) and s2 (990 h), but showed an increased practice exposure time from s1 (3 090 h) to s2 (3 770 h). furthermore, this team had a considerable increase in match exposure time from s1 (1 824 h) to s2 (2 071 h), which contributed to an increase in total exposure time from s1 (5 874 h) to s2 (6 831 h). team 4 only reported the exposure data for s2 – therefore no comparison can be made from s1 to s2, which would be a slight limitation when analysing this exposure time. the exposure time per team showed that team 2 had a considerably greater fitness exposure time than the other teams in both seasons, while still maintaining a higher-than-average practice exposure time per season, which seemed to be the focus of the other teams for both seasons. moreover, in s2 team 2 maintained their total exposure time while increasing their fitness exposure time and decreasing their practice exposure time. discussion the first important finding was that the injury incidence for provincial cricketers was 30 /10 000 hours. this was greater than for west indian provincial players4 (14/10 000 h) and west indian provincial (22/10 000 h) and australian test (23/10 000 h) teams.3 the south african provincial players also showed a lower injury incidence than the west indian test and odi players (49 and 41/10 000 h). the south african results were similar to those of the australian odi players (39/10 000 h).3,4 the injury incidence of the south african provincial players showed a decrease from s1 (34/10 000 h) to s2 (27/ 10 000 h). however, there was an increase in total exposure time which was mainly because of an increase in the training and practice exposure time. a possible explanation for this decrease in injury incidence could be that the match incidence of injury (74/10 000 h) is far less than the training incidence of injury (15/10 000 h). secondly, the injury prevalence in the south african provincial cricketers (8%) was similar to that in the west indian odi (8%) and australian test (7%) players and less than that in the west indian test (11%) and australian odi (10%) players.3,4 however, there was an increase in injury prevalence from s1 (3%) to s2 (8%), possibly as a result of a number of interdependent factors. it could be due to an increased number of matches being played from s1 to s2, resulting in an increase in match exposure time. there was an increase in the incidence of injury during the early part of the season, coinciding with an increased exposure time. this increased seasonal exposure time, with an emphasis on preand early-season activity, could have resulted in the increased incidence of injuries during the early part of the season. as the season progressed the incidence of injuries decreased, as did the match exposure time (242 h and 433 h, respectively), during the middle and end of the season. the increased number of injuries during the early part of the season could also be related to playing more first-class (4-day) cricket at the beginning of the season, with limited-over cricket matches being played towards the middle and end of the season with less match exposure time. during the longer version of the game the players tend to be relatively inactive for long periods of time before rapidly moving after the ball when fielding. bowlers may be required to bowl multiple spells, sometimes accumulating over 20 overs in a day, compared with 4 9 over spells in limited-over cricket. this could have resulted in the large number of injuries during fielding and bowling, particularly during the early part of the season, and could have been further influenced by the fact that during the time period 154 sajsm vol 21 no. 4 2009 table vii. month during the two-season period when the injuries occurred s1 s2 st n % n % n % pre-season august september season 83 99 81 84 164 91 january 10 9 19 february 7 15 22 march 16 17 33 october 10 10 november 21 16 37 december 19 24 43 off-season 1 1 15 16 16 9 april 1 3 4 may 12 12 june july total 84 100 96 100 180 100 s1 – 2004 2005 season. s2 – 2005 2006 season. st – 2004 2005 and 2005 2006 seasons. the percentages have been rounded. table viii. exposure time (hours) of the teams during the two-season period s1 s2 st team 1 match 2 210 2 288 4 498 fitness 2 075 407 2 482 practice 3 420 6 570 9 990 total 7 735 9 265 16 970 team 2 match 2 253 2 149 4 402 fitness 3 005 3 895 6 900 practice 5 825 5 075 10 900 total 11 083 11 119 22 202 team 3 match 1 824 2 071 3 895 fitness 960 990 1 950 practice 3 090 3 770 6 860 total 5 874 6 831 12 705 team 4 match nr 2 037 2 037 fitness nr 1 565 1 565 practice nr 5 430 5 430 total nr 9 032 9 032 mean match 2 096 2 136 2 472 fitness 2 013 1 714 1 612 practice 4 112 5 211 4 148 s1 – 2004 2005 season. s2 – 2005 2006 season. st – 2004 2005 and 2005 2006 seasons. nr – not reported. between first-class matches more emphasis was placed on rest with little time devoted to fitness maintenance activities. a large number of injuries in the first season were first-time injuries of an acute nature, including impact injuries, particularly when batting, resulting in haematomas and other trauma injuries. however, in the second season there was an increase in recurring injuries from the previous season that was accompanied by an increase in acute-on-chronic injuries, the majority being muscle strains, tendinopathies and acute sprains. the above could also have been the result of the players returning to play without being fully rehabilitated and because of the nature of the injury sustained. the primary mechanisms of injury were bowling and running to and sliding for the ball when fielding. similar results were found in many of the west indian players, where injuries were muscle strains caused by running after and picking up the ball and injuries to young fast bowlers.3 these activities all involve some kind of stop-start movement and/or change in direction of the whole body, requiring strength, agility and flexibility. in sports involving bouncing and jumping activities with a high intensity of a stretch-shortening cycle, a stretching programme significantly influenced the viscosity of the tendon, making it more compliant. stretching may also be beneficial for injury prevention.7 further investigation of the exposure time for team 2 shows that they had the greatest fitness exposure time of the 4 teams, yet their injury prevalence was the lowest and decreased considerably from the first to the second season. one of the reasons for the decreased injury prevalence could have been that their fitness focused more on stretching, with dispersed activities of aerobic and core stability work. this increased fitness exposure time, particularly stretching activity, without the comparable decrease in practice exposure time, could reduce the injury prevalence of cricket players and possibly the number of injuries from season to season. the other teams focused more on strength and aerobic activities with limited focus on stretching exercises. conclusion injury incidence and prevalence in south african provincial cricketers are similar to those in the west indian and australian studies. it would appear that injury prevalence can increase independently from injury incidence. although the injury incidence was at an acceptable level, the injury prevalence still remains a concern and highlights the importance of receiving correct treatment and sufficient recovery time before returning to cricket. increasing fitness exposure time, particularly stretching, could decrease the number of flexibility-related injuries. the correct fielding techniques and the number of overs bowled could be more closely monitored to decrease the injury prevalence. references 1. leary t, white j. acute injury incidence in professional county cricket players (1985-1995). br j sports med 2000;34:145-147. 2. stretch ra, venter djl. cricket injuries – a longitudinal study of the nature of injuries to south african cricketers. s afr j sports med 2002; 36: 270-275. 3. orchard j, james t, alcott e, carter s, farhart p. injuries in australian cricket at first class level 1995/1996 to 2000/2001. br j sports med 2002;36:270-275. 4. mansingh a, harper l, headley s, king-mowatt j, mansingh g. injuries in west indian cricket 2003-2004. br j sports med 2006;40:119-123. 5. orchard j, newman d, stretch r, frost w, mansingh a, leipus a. methods for injury surveillance in international cricket. j sci med sport 2005;8(1):1-14. 6. orchard j. orchard sports injuries classification system (osics). in: bloomfield j, ficker p, fitch k, eds. science and medicine in sport. 2nd ed. melbourne: blackwell, 1995:674-681. 7. witvrouw e, mahieu n, danneels l, mcnair p. stretching and injury prevention: an obscure relationship. j sports med 2004;34(7):443-449. sajsm vol 21 no. 4 2009 155 32 sajsm vol 20 no. 1 2008 introduction physical activity is important for the health status of any age group, and especially for young people. studies show that children and adolescents who participate in regular physical activity can gain psychological health and skeletal health benefits. 3 regular physical activity is associated with enhanced health and reduced risk of all-cause mortality, it improves aerobic capacity, muscular strength, body agility, co-ordination and metabolic functioning, exemplified by improvements in bone density, lipid profiles, insulin levels and immune function. 28 those who are physically active have a reduced risk of developing cardiovascular disease and ischaemic stroke, 30 non-insulin-dependent (type 2) diabetes, 12 colon cancers, 2 and osteoporosis. 25 physical activity is also consistently related to higher levels of self-esteem and lower levels of anxiety and stress. 27 however, while the positive effects of regular physical activity are well established in children and adolescents, there is evidence that young people in many developed nations do not participate in regular physical activity of the type and intensity associated with health. as a result, the prevalence of childhood obesity is increasing worldwide. 19 since obesity is associated with increased morbidity and mortality, the world health organization has compared the marked increase to a global epidemic disease. 31 the overweight and obese child is not physically active, has a sedentary way of life and no interest in exercise. psychological consequences of obesity may have a powerful effect on the self-image and social standing of the overweight and obese child during critical phases of emotional development. studies evaluating the influence of obesity on mental health portray a disturbing picture of depression, low self-esteem, poor body image, and social isolation. the failure to achieve success with dieting and other therapeutic interventions may potentiate these negative feelings, and the inability to participate in physical activity and discrimination by peers and adults are further contributing influences. 24 many studies have shown that obese children and adolescents are physically less active and less fit than their non-obese peers. 9 physical fitness is generally considered to be ‘the ability to perform daily tasks without fatigue’. physical fitness includes several components: cardiorespiratory fitness, muscular endurance, muscular strength, flexibility, co-ordination and speed. 6 original research article physical fitness, nutritional habits and daily locomotive action of 12-year-old children with different body mass index abstract objective. the purpose of this study was to examine the differences in physical fitness, daily nutritional habits and locomotive behaviour among pupils with varying body mass index (bmi) in the 5th and 6th grades of primary school. design. the sample consisted of 480 pupils (229 boys and 251 girls), who participated in specific eurofit tests and completed questionnaires probing their physical activity and nutritional habits. they were divided according to their bmi into normal, overweight or obese children. main outcome measures. 18% and 8% of the pupils were categorised as overweight and obese, respectively. results. from the data analysis (two-way anova), with bmi and gender as independent variables, it was found that the obese and overweight pupils had lower performance in long jump, in 30-m speed and in 20-m shuttle run. they adopted sedentary daily habits, such as many hours of tv watching and unhealthly nutritional habits. conclusions. the results of this study support the need for intervention at school through physical education and health education lessons, to inform pupils about the health risks associated with limited physical activity and unhealthy nutritional habits. another goal should be to motivate and create behaviours that are conducive to better lifestyle habits. correspondence: spiridon kamtsios euergeton 42, tk 45333 ioannina greece tel: +06 4-633-8714 e-mail: spiroskam@sch.gr spiridon kamtsios (msc) physical education teacher, ioannina, greece pg32-36.indd 32 4/23/08 11:34:20 am sajsm vol 20 no. 1 2008 33 increasing physical activity is one of the key elements in the treatment of childhood obesity. 23 however, motivating obese subjects to adhere to an activity programme is a major challenge. 26 to improve adherence one must develop an exercise programme that is manageable for obese children and adolescents. 23 interventions that are not tailored to the fitness levels of obese participants may discourage future participation in physical activity. the ability to develop physical activity programmes suited to obese participants requires further investigation of different components of physical fitness in this population. the purpose of this study was to examine the differences in physical fitness, daily nutritional habits and locomotive behaviour among pupils with varying body mass index (bmi) in the 5th and 6th grades of primary school. the hypothesis of the research is that overweight and obese children will have differences in fitness levels and they will adopt a sedentary lifestyle. material and methods participants and study design the study included 480 children (229 boys and 251 girls) aged 11 12 years (mean 11.62 ± 0.60 years), attending the 5th and 6th grade classes of primary schools which were selected with stratified sampling in suburban and urban areas of west-northwest greece. the nature and purpose of the study were explained to parents before consent was obtained, and participation was on a voluntary basis. the measurements and the tests that the children underwent were carried out during the first two school hours. the data collected included anthropometric measurements as well as motorand health-related fitness parameters. anthropometric measurements age (accurate to 1 month) was recorded. height was measured with a stadiometer to the nearest 0.5 cm. body mass was measured on a balance-beam scale accurate to 0.1 kg. the students were barefoot, wearing light clothing to decrease the additional weight. body mass index (bmi) was calculated by dividing weight by height squared (kg.m -2 ). 7 physical fitness measurements the physical fitness of the children was evaluated with the eurofit test battery, 8 which is designed for the assessment of healthrelated fitness in children and adults. eurofit for children is designed to be practical and applicable under conditions available in ordinary communities. the children wore athletic shoes and athletic clothes and underwent the following tests that measure different components of fitness. • sit and reach (sar): reaching as far as possible from a sitting position. this test measures the flexibility of posterior muscles. • standing long jump with feet together (slj): the maximum horizontal distance attained was measured. this test evaluates the explosive strength of the legs. • sit-ups (sup): the maximum number of sit-ups achieved in 30 seconds was recorded. this test measures the trunk strength (muscular endurance). • overhand throw: the test measures the strength of the upper body limbs. • 30-meter sprint (from standing position): this test measures speed. • 20-meter multistage aerobic shuttle run test (mat): this test evaluates the maximum aerobic capacity based on an indirect-incremental-maximum field test involving a 20-meter shuttle run, using the formula proposed by léger et al. to calculate the maximal oxygen consumption (vo2max). 16 students’ daily locomotive and nutritional habits responders were asked how often and how many times each week they ‘participated in sports, swimming or other physical activities, excluding mandatory physical education classes in school’. they were also asked about their nutritional habits during the last week and about their sedentary habits (‘how many hours do you watch tv on a week day and on the weekend?’). statistical analyses descriptive statistics were performed for all parameters. a twoway anova was used to examine differences in group means. a sidak post hoc test was used to identify differences among gender and bmi categories (sidak was used to compare variables from different data collections) and effect sizes (η2 -– i.e. proportion of the total variance that is attributed to an effect) were calculated to assess the significance of the differences in fitness performance among bmi categories. comparisons were considered significant at a p-value of 0.05 or less. chi-square tests were used to detect differences between normal, overweight and obese children in their daily locomotive and nutritional habits. spss version 11.0 software was used for all statistical calculations. results when the entire sample including both genders was analysed, 74% of the participants had a normal bmi, 18% were overweight and 8% were characterised as obese. the differences in the fitness parameters among bmi categories by gender are presented in table i. two-way anova results revealed a significant effect of bmi and gender in the multistage aerobic shuttle run test (p=0.001, η2=0.028), and in flexibility (p=0.002, η2=0.025). specifically, normal boys performed better than their obese counterparts in standing long jump (p=0.000, η2=0.111), in sit-ups (p=0.010, η2=0.019), in sprint (p=0.000, η2=0.237), and in the multistage aerobic shuttle run test (p=0.001, η2=0.08). in addition, overweight boys demonstrated better performance than obese boys in the standing long jump, the overhand throw, sprint and in the multistage aerobic shuttle run test (p-values between 0.004 and 0.001). normal-weight girls performed better in the sprint than their overweight and obese counterparts (p=0.001). in the comparison of physical fitness tests between genders within the bmi categories, boys obtained better results than girls for all tests except flexibility. tables ii and iii present the results of chi-square tests examining the differences between some discernible variables related to the daily athletic, locomotive and nutritional habits. significant differences were found between the three cohorts, with the obese children displaying a higher percentage in all categories. pg32-36.indd 33 4/23/08 11:34:21 am 34 sajsm vol 20 no. 1 2008 discussion the principal findings in the present study were that obese and overweight pupils had lower performance in specific physical fitness tests and they adopted sedentary daily habits, such as many hours of tv watching and unhealthy nutritional habits. our results support the findings of previous studies in greece 20,10,18 and in other countries 4,29 that the prevalence of overweight and obesity in 10 12-year-olds was approximately 30%. the results showed that overweight and obese students had inferior performances in all tests requiring propulsion or lifting of the body mass (standing-broad jump, sit-ups, and endurance shuttle run). these poorer performances in obese individuals are probably due to the fact that their excess body fat is an extra load to be moved during weight-bearing tasks. another explanation could be that obese children and adolescents avoid weightbearing activities because of the greater energy cost compared with normal-weight children. in this case, the poorer performance could also be a consequence of a lack of experience in weightbearing tasks. because obese young boys and girls are limited in their ability to perform weight-bearing activities, such activities should be limited at the start of an intervention programme. activities that are not tailored to the capabilities of bigger children may discourage continued participation by obese individuals. 9 once levels of fatness have decreased and/or fitness levels have improved, weight-bearing tasks may be much less exhausting and should be progressively included in the programme. 9 no relationship was found between obesity and flexibility, something that was mentioned in previous studies. 21 useful non-weight-bearing alternatives such as cycling, swimming or other aquatic activities should be the focus in the early stages of a programme and then continued as an appropriate means of balancing various types of activity. 9,23 the second research question was related to differences in the children’s nutritional habits and in their daily locomotive habits. results showed that overweight and obese children watched more hours of tv in the weekday and the weekends. other studies have also found negative relationships between television viewing times and obesity. 14 television watching replaces more vigorous activities. there is a positive correlation between time spent watching television and being overweight or obese in populations of different ages. prevalence of obesity has increased as well as the number of hours that tv networks dedicate to children. 13 in addition, children are exposed to many unhealthy stimulations in terms of food intake when watching television. over the last few years, the number of television food commercials targeting children have increased, especially junk food. the current use of food in movies, shows and cartoons may lead to a misconception of the notion of healthy nutrition and stimulate an excessive intake of poor nutritional food. 5 another finding of this study was that overweight and obese children were less likely to join an organised athletic club. sports clubs may be too competition oriented and therefore not appropriate for the less-fit children and adolescents, which table i. mean (sd) differences in the fitness parameters among bmi categories by gender boys (n=229) (47.7%) girls (n=251) (52.3 %) normal overweight obese normal overweight obese fbmi fgender f bmi xgender n=162 n=46 n=21 n=194 n=38 n=19 motor fitness tests sar (cm) 14.11,2 ± 6.1 11.01,3 ± 9.3 13.74 ± 7.3 19.12 ± 6.1 21.43 ± 4.8 18.14 ± 8.3 .25 57.8* 6.1* slj (cm) 1.41,2 ± 0.17 1.31,3 ± 0.2 1.21 ± 0.2 1.91,2 ± 0.14 1.21,3 ± 0.1 1.1 ± 0.1 29.6* 13.4* .08 sup (reps in 30s) 18.11 ± 4.7 19.3 ± 4.1 14.8 1 ± 4.3 17.8 ± 4.5 18.1 ± 5.1 16.5 ± 5.5 4.61* 2.6 2.2 othr (m) 4.92 ± 1.5 5.41 ± 1.7 4.41 ± 2.9 4.32 ± 1.3 4.9 ± 1.5 3.9 ± 1.9 5.8* 6.4* .16 spr (s) 5.91 ± 0.4 6.21,3 ± 0.5 6.91 ± 0.2 6.21,2 ± 0.46 6.51,3 ± 0.4 7.11 ± 0.1 73.6* 17.2* .14 mat (ml kg -1 min -1 ) 29.81,2 ± 9.4 23.91 ± 5.0 24.1 ± 4.8 24.72 ± 4.3 24.6 ± 4.1 21.7 ± 1.5 13.6† 6.4† 6.8† values are mean ± sd sar = sit and reach; slj = standing long jump; sup = sit ups; othr = overhand throw; spr = sprint; mat = multistage aerobic shuttle run test 1=differences between normal, overweight and obese 2=gender differences between normal children 3=gender differences between overweight children 4=gender differences between obese children *significantly different at the 0.05 level †significantly different at the 0.001 level table iii. results of chi-square test concerning daily athletic and locomotive habits chi-square test school team member χ2(2) =23.9* p=0.000 participation as an athlete in a club χ2(2) =10.9* p=0.004 exercise during leisure time with friends χ2(2) =3.4 p=0.186 tv daily χ2(2) =14.1* p=0.028 daily pc usage χ2(2) =2.2 p=0.703 *values significantly different (p<0.05). table ii. results of chi-square test concerning daily nutritional habits nutritional habits chi-square test salad χ2(2) =0.8 p=0.669 fruits χ2(2) =30.2* p=0.000 cereals χ2(2) =2.0 p=0.368 milk χ2(2) =2.1 p=0.353 hamburger χ2(2) =55.7* p=0.000 coca-cola χ2(2) =38.2* p=0.000 * values significantly different (p<0.05). pg32-36.indd 34 4/23/08 11:34:22 am 36 sajsm vol 20 no. 1 2008 would include the obese. given the commonly low levels of sports participation by the obese, the encouragement of sports participation from an early age may be important in the prevention and treatment of overweight. 9 no relationship was found between video game/computer use and the bmi among children. this may be because primary school children in this study spent relatively little time in these activities, because these activities are less sedentary than television viewing, or due to other factors which were not explored in this study (i.e. no food advertising, hands not free for eating during video game/computer use). there is not much research to which we could compare our findings. 29 the phenomenon of fatness and all its contributory factors in childhood and adolescence is an important problem – it can become one of the most common diseases and can turn into a world-wide epidemic. important causes for this are lack of physical activity and sedentary lifestyle. a goal for managing the overweight and obese children is to urge them to become physically active, in an attempt to influence them to adopt these habits as adults. in addition to the physical effects, this will also have psychological and social benefits. 22 exercise programmes include lifestyle changes, e.g. walking instead of taking a bus, using stairs instead of lifts, as well as exercise in a planned and structured manner, e.g. participating in sport or gymnastic groups. another aspect is that inactive periods (sedentary activities, tv and video viewing, etc.) during the day should be exchanged as much as possible for active behaviour. recent studies suggest that decreasing sedentary activity is very effective in promoting weight loss. 32 strategies to increase physical activity are therefore key elements in the treatment of childhood obesity, along with changes in eating behaviour. 9 the current environmental experience of young children includes few opportunities for physical activity. to prevent obesity and later metabolic disease, all sectors of society must work together to support strategies to change public opinion and behaviour across the lifespan. schools should be primary targets for efforts to educate children on the reduction of tv time, computer games and unhealthy snacks. schools should provide daily physical education and frequent periods of unstructured play in young children. school interventions through physical education lessons must be provided to inform children about health risks related to inactivity and unhealthy nutritional habits. another goal should be to motivate and create behaviours that are conducive to better lifestyle habits. references 1. brewer j, ramsbottom r, williams c. multistage fitness test. a progressive shuttle run test for the prediction of maximum oxygen uptake. leeds, uk: national coaching foundation, 1988. 2. brownson rc, chang jc, davis jr, smith ca. physical activity on the job and cancer in missouri. am j publ health 1991; 81: 639-42. 3. calfas cj, taylor wc. effects of physical activity on psychological variables of children. ped exerc science 1994; 6: 406-23. 4. canning p, courage m, frizzell l. prevalence of overweight and obesity in a provincial population of canadian preschool children. j canad med assoc 2004; 171(3): 101-7. 5. 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27-40. 11. frontini mg, bao w, elkasabany a, srinivasan sr, berenson g. comparison of weight-for-height indices as a measure of adiposity and cardiovascular risk from childhood to young adulthood: the bogalusa heart study. j clin epidem 2001; 54: 817-22. 12. fulton-kehoe d, hamman rf, baxter j, marshall j. a case-control study of physical activity and non-insulin dependent diabetes mellitus (niddm). the san luis valley diabetes study. ann epidem 2001; 11: 320-27. 13. hardus pm, vuuren c, crawford d, worsley a. public perceptions of the causes and prevention of obesity among primary school children. intern j obes 2003; 27: 1465-71. 14. janssen i, katzmarzyk p, boyce n. comparison of overweight and obesity prevalence in school aged youth from 34 countries and their relationships with physical activity and dietary patterns. obes rev 2005; 6: 123-32. 15. katzmarzyk pt, tremblay a, perusse l, despres j, bouchard c. the utility of the international child and adolescent overweight guidelines for predicting coronary heart disease risk factors. j clin epidemiol 2003; 56: 45662. 16. léger la, mercier d, gaboury c, lambert j. the multistage 20-m shuttle run test for aerobic fitness. j sports sci 1988; 6(2): 93-101. 17. lindsay rs, hanson rl, roumain j, ravussin e, knowler wc, tataranni pa. body mass index as a measure of adiposity in children and adolescents: relationship to adiposity by dual energy x-ray absorptiometry and to cardiovascular risk factors. j clin endocrinol metab 2001; 86: 4061-67. 18. magkos f, manios y, christakis g, kafatos ag. secular trends in cardiovascular risk factors among school-aged boys from crete, greece, 19822002. europ j clin nutrit 2005; 59: 1-7. 19. marild s, bondestam m, bergstrom r, ehnberg s, hallsing a, albertssonwikland k. prevalence trends of obesity and overweight among 10-yearold children in western sweden and relationships with parental body mass index. acta pediatr 2004; 93: 1588-95. 20. mamalakis g, kafatos a, manios y, anagnostopoulou t. apostolaki i. obesity indices in a cohort of primary school children in crete: a six-year prospective study. int j obesity 2000; 24: 765-71. 21. minck mr, ruiter lm, van mechelen w, kemper hc, twisk jw. physical fitness, body fatness, and physical activity: the amsterdam growth study. j hum biol 2000; 12: 593-9. 22. mοta j, santos p, guerra s, ribeiro j, duarte j. differences of daily physical activity levels of children according to body mass index. pediatr exer scie 2000; 14: 442-52. 23. parizková j, hills a. childhood obesity: prevention and management. boca raton: crc press, 2001. 24. rowland t. exercise and children’s health. in: cheung w, richmond j, eds. obesity and physical activity. champaign, il: human kinetics publishers, 1990: 129-159. 25. rubin k, schirduan v, gendreau p, sarfarazi m, mendola r, dalsky g. predictors of axial and peripheral bone mineral density in healthy children and adolescents, with special attention to the role of puberty. j pediatr 1993; 123: 863-70. 26. sothern ms, hunter s, suskind rm, brown r, udall jn, blecker u. motivating the obese child to move: the role of structured exercise in pediatric weight management. south med j 1999; 92: 577-83. 27. theodorakis y, natsis p, papaioannou a, goudas m. correlation between exercise and other health related behaviors in greek students. int j phys educ 2002; 39: 30-4. 28. us department of health and human services. physical activity and health: a report of the surgeon general. atlanta, ga: us centers for disease control and prevention, 1996. 29. wake m, hesketh k, waters e. television, computer use and body mass index in australian primary school children. j pediatr child health 2003; 38: 130-34. 30. wannamethee sg, shaper ag. physical activity in the prevention of cardiovascular disease: an epidemiological perspective. sports med 2001; 31: 101-14. 31. world health organization. obesity: preventing and managing the global epidemic. report of a who consultation. world health organization, technical report series 894. geneva: who, 2000. 32. zwiauer k. prevention and treatment of overweight and obesity in children and adolescents. j pediatr 2000; 159: 56-68. pg32-36.indd 36 4/23/08 11:34:23 am introduction the need for talent identification in sport has developed into a science. according to singer et al. 1 talent identification in sport aims to predict future achievements based on the present abilities and potential of a sportsperson. most of the game-specific skills, anthropometric measurements and physical/motor abilities, including speed, strength, power and agility, change in young sportsmen during their development years (8 18 years of age). 2 considering the sport of rugby, the limited number of years during which a rugby player is able to play elite rugby have necessitated the early identification of potential rugby talent, as well as ways and means to improve the performance of rugby players from an early age. 2 the lack of knowledge in this regard as well as the non-availability of comparative data between countries, are limiting factors. comparisons of elite rugby players in top rugby-playing nations such as south africa, new zealand, the uk and australia, may assist coaches and sport scientists to identify talented rugby players at a younger age, and to develop these players to a higher international standard. however, these types of studies are limited. besides a comparative study between south african and british rugby youth, 3 and a comparative study between 12-year-old new zealand and south african rugby players, 4 no other published studies comparing international rugby players could be found. the fact that south africa and new zealand are currently voted number one and two in the world of rugby makes for an interesting comparison of their elite youth rugby players. the purpose of this investigation was to conduct such a comparative study between elite u/16 rugby players of these two nations. the main aim was to provide information regarding the physical profile of u/16 rugby players and hopefully to stimulate future research on talent identification and development. methods three groups of elite u/16 rugby players from new zealand and south africa participated in this study. for the purpose of this investigation the term ‘elite rugby players’ refers to u/16 rugby players who played provincial rugby at school level. the first study group comprised 24 members of the taranaki provincial u/16 a rugby team in new zealand, 5 the second group comprised 43 u/16 elite high-school rugby players in the north-west province in south africa, 6 and the third group comprised 21 u/16 rugby players in the north-west province competing in the national tournament. 7 the first study group was tested during the mid-rugby season of 2004 in new zealand. 5 the second study group was tested during the rugby season of 1996 6 and the third study group was tested during the mid-rugby season of 2002. 7 the test protocol consisted of anthropometric measurements, rugby-specific skill tests, and physical and motor ability tests. the detailed descriptions of the battery of tests executed can be found in the relevant references; however, the aims of the different tests will be described in short. original research article comparative characteristics of elite new zealand and south african u/16 rugby players with reference to gamespecific skills, physical abilities and anthropometric data abstract objective. a comparative study of elite new zealand and south african u/16 rugby players with special reference to game-specific skills, physical abilities and anthropometric data. design and settings. a battery of tests was used to obtain information concerning a group of elite new zealand players (n=24) and two elite south african groups (n=64). information was obtained for game-specific skills, physical abilities, and anthropometric data. results. the new zealand players outperformed the south african players in game-specific tests, physical abilities, and anthropometric measurements. where the south african groups performed better than the new zealand group, it was not practically significant. conclusion. south african rugby authorities should be cognisant of the areas where south african u/16 rugby players were outperformed by their new zealand counterparts, and consequently develop specific development programmes to address these shortcomings. correspondence: professor e j spamer director, school for continuing teachers’ education north-west university potchefstroom 2520 south africa e-mail: manie.spamer@nwu.ac.za emanuel j spamer (phd)1 daniël j du plessis (med)2 ernst h kruger (phd)2 1 north-west university, private bag x6001, school of continuous teacher education, north-west university, potchefstroom 2 department of biokinetics, sport and leisure sciences, university of pretoria sajsm vol 21 no. 2 2009 53 anthropometric tests standard measurements were performed for body composition. these included body mass, stature, skinfolds (triceps, subscapular, mid-axilliary, pectoral, supraspinal, abdominal, thigh and calf skinfold for prediction of body fat and sum of skinfolds), and girths (flexed upper arm, forearm, thigh, calf and ankle). 8 54 sajsm vol 21 no. 2 2009 table i. descriptive statistics and significant differences (d-values) between elite u/16 new zealand and south african players with reference to anthropometric components tests new zealand south africa south africa new zealand new zealand n=24 group 1 group 2 v. v. n=43 n=22 south africa south africa group 1 group 2 sd sd sd d-value d-value mass (kg) 81.26 ± 8.31 72.82 ± 9.63 76.64 ± 11.41 0.9* 0.4 height (cm) 179.71 ± 5.83 177.63 ± 5.64 180.86 ± 8.22 0.4 0.1 skinfolds (mm) tricep 12.96 ± 4.48 12.68 ± 5.56 8.02 ± 2.81 0.05 1.1* sub-scapular 14.46 ± 7.06 10.99 ± 4.41 10.32 ± 2.77 0.5 0.6 mid-axilla 13.25 ± 7.57 9.63 ± 4.49 0.5 supra-spinal 20.69 ± 9.29 11.91 ± 5.54 0.9* pectoral 9.73 ± 3.44 6.80 ± 2.75 5.73 ± 2.30 0.9* 1.2* abdominal 20.73 ± 9.89 15.60 ± 8.92 12.64 ± 6.52 0.5 0.8* thigh 17.15 ± 5.22 15.45 ± 5.18 10.77 ± 4.01 0.3 1.2* calf 11.75 ± 4.64 10.95 ± 4.44 7.11 ± 2.84 0.2 1.0* % body fat 13.66 ± 4.77 18.77 ± 6.44 15.96 ± 3.96 0.8* 0.5 girth (cm) flexed upper arm 33.73 ± 2.88 32.05 ± 2.33 32.57 ± 2.83 0.6 0.4 forearm 28.41 ± 1.58 27.45 ± 1.66 27.93 ± 1.91 0.6 0.3 ankle 24.80 ± 1.22 23.89 ± 1.71 24.14 ± 3.19 0.5 0.2 calf 38.14 ± 2.70 36.97 ± 3.68 36.77 ± 4.21 0.3 0.3 upper leg 57.00 ± 3.46 56.02 ± 4.36 0.2 *practical significant difference: d≥0.8 (large effect). tendency towards practical significant difference: 0.5≤d≤0.7 (medium effect). small or no practical significant difference: d≤0.4 (small effect). = average. x x x x table ii. descriptive statistics and significant differences (d-values) between elite u/16 new zealand and south african players with reference to physical and motor abilities tests new zealand south africa south africa new zealand new zealand n=24 group 1 group 2 v. v. n=43 n=22 south africa south africa group 1 group 2 sd sd sd d-value d-value sit and reach (cm) -2.21 ± 8.75 2.36 ± 2.30 5.91 ± 6.80 0.02 0.9* vertical jump (cm) 50.07 ± 7.00 47.16 ± 6.11 40.55 ± 10.67 0.3 0.9* speed endurance (%) 5.38 ± 1.48 6.37 ± 3.15 6.58 ± 3.21 0.3 0.4 zig-zag run (s) 6.65 ± 0.44 7.16 ± 0.48 1.1* speed 10 m (s) 1.79 ± 0.09 1.89 ± 0.20 0.5 speed 45.7 m (s) 6.21 ± 0.38 6.61 ± 0.34 1.1* flexed arm hang (s) 38.63 ± 16.17 26.03 ± 12.04 0.8* *practical significant difference: d≥0.8 (large effect). tendency towards practical significant difference: 0.5≤d≤ 0.7 (medium effect). small or no practical significant difference: d≤0.4 (small effect). = average. x x x x physical and motor ability tests these included the sprinting test (done over 45.7 m to assess the speed ability of the players 9 ), the explosive power test (vertical jump test to assess explosive power strength 10 ), the flexibility test (adapted sit-and-reach test to assess flexibility in the lower back and hamstrings 10 ), the agility test (zig-zag run over 24 m to assess agility and speed running 9 ), the speed endurance test (also known as the test of hazaldine and mcnab 11 in which the players did a number of sprints with 20-second rest periods to assess speed endurance ability), and the flexed arm hang (hanging on a horizontal bar to assess upper body muscle endurance. 2 game-specific skills tests these tests included passing for accuracy (while the rugby player is jogging he passes a ball through a circle 4 m away to assess the passing accuracy to his right and left 2 and another accuracy passing test over 7 m with the player not moving 9 ), passing for distance (the player attempts to pass a rugby ball to a standing partner to assess distance of passing), ground skills test (while running the player picks the ball up, runs around a marker, and places the ball where it was picked up, to assess ground skill while running 12 ), kicking for distance (the player takes the ball in both hands and kicks the ball as far as possible to assess kicking distance; place-kicking using a tee, with an unlimited approach, was also used for the same test 9 ), air and ground kicking ability (the rugby player performed a chip, followed by a grubber with both feet to assess both skills 12 ), and side-step ability (carrying the ball in both hands, running through obstacles and side-stepping to the left and right to assess the ability to dodge 13 ). these anthropometric, physical and motor abilities and rugby game-specific tests have been used by several researchers in the field of talent identification in rugby. 2,3,6,7 it must be acknowledged that some of the tests favour certain rugby-specific positions and this should be taken into account for talent identification. another point to note is that the battery of tests used for the three sampling groups was spread over time and the researchers in each study did not always use the full battery of tests. in a few of the tests the new zealand players were only compared with one of the south african groups instead of both groups, due to the fact that the two south african groups did not perform the same battery of tests. the three studies referred to in this paper form part of an international project (south africa, new zealand and england) on talent identification among young rugby players, and were managed from the north-west university. the facilitators who conducted the tests were all trained by the same research team to ensure that the test procedures were identical in all three studies. order of testing anthropometric and flexibility measurements were investigated first. the rugby players did a general warm-up consisting of jogging and stretching of all major muscle groups, as well as short sprints. all the physical, motor and rugby-specific tests were done on a rotation basis. the speed endurance test was conducted last, after the players had been allowed sufficient rest. statistics data of all the groups were analysed with the sas computer software programme. 14 descriptive statistics (means and standard deviation) were annotated. because of the relatively small size and nature of the study groups (convenience sampling), d-values (effect sizes) were calculated to determine practical significant differences between the new zealand and south african groups. 15 results anthropometric data table i shows that the eight skinfold measurements (averages) obtained for the nz group, were all higher than the same skinfold measures of both sa groups. practical significant differences (large effect size) were found between the nz and sa1 groups with regard to the supra-spinal (d=0.9) and pectoral (d=0.9) skinfolds; and between the nz and sa2 groups with regard to tricep (d=1.1), pectoral (d=1.2), abdominal (d=0.8), thigh (d=1.2), and calf (d=1.0) skinfolds. table i shows that nz also scored higher in the following girth meassajsm vol 21 no. 2 2009 55 table iii. descriptive statistics and significant differences (d-values) between elite u/16 new zealand and south african players with reference to game-specific skills tests new zealand south africa south africa new zealand new zealand n=24 group 1 group 2 v. v. n=43 n=22 south africa south africa group 1 group 2 sd sd sd d-value d-value ground skills (s) 3.27 ± 0.22 5.68 ± 0.36 3.62 ± 0.25 6.7* 1.4* side steps (/10) 5.96 ± 2.46 4.46 ± 1.35 5.50 ± 1.40 0.6 0.2 air and ground kicks (/10) 7.13 ± 1.92 4.60 ± 1.90 5.19 ± 0.93 1.3* 1.0* passing distance (m) 21.96 ± 2.71 19.95 ± 3.27 21.14 ± 4.34 0.6 0.2 passing accuracy 3.83 ± 1.88 4.23 ± 2.36 4.50 ± 2.28 0.1 0.3 over 4 m (/10) passing accuracy 24.42 ± 3.12 25.69 ± 2.57 23.55 ± 5.76 0.4 0.2 over 7 m (/30) kicking distance (m) 40.90 ± 4.60 38.02 ± 6.56 41.41 ± 11.13 0.4 0.04 kick-off distance (m) 37.59 ± 4.37 36.07 ± 7.80 33.60 ± 9.18 0.2 0.4 *practical significant difference: d≥0.8 (large effect). tendency towards practical significant difference: 0.5≤d≤ 0.7 (medium effect). small or no practical significant difference: d≤0.4 (small effect). = average. x x x x urements: flexed upper arm, forearm, ankle, calf and upper leg. the nz players in this study were heavier than the sa groups, but slightly shorter than sa2. a tendency towards practical significant differences (medium effect size) was found between the nz and sa1 groups in the flexed upper arm (d=0.6), forearm (d=0.6) and ankle (d=0.5) girth measurements. physical and motor abilities table ii shows that the nz group performed better than both sa groups in six of the seven tests for physical and motor abilities. the only physical and motor test in which the sa groups performed significantly better than the new zealand group, was in the sit-andreach test. large practical significant values were found between the nz group and the sa1 group in the zig-zag run (d=1.0) and the 45.7 m speed test (d=1.1); the times of the nz group were faster in both tests. practical significant differences were found between the nz and sa2 groups in the sit-and-reach (d=0.9), vertical jump (d=0.9), and flexed arm hang tests (d=0.8). no practical significant differences (small effect size) were found in the speed endurance test (sa1: d=0.3; sa2: d=0.4). a tendency towards practical significant difference (medium effect) was found in the speed over 10 m test (sa2: d=0.5). game-specific skills table iii shows that the nz group outperformed their sa counterparts in six of the eight tests. the results show practical significant differences (large effect size) between the nz and both the sa groups in only two of the eight game-specific skill tests, namely: ground skills (nz v. sa1: d=6.7; and nz v. sa2: d=1.4) and air and ground kicks (nz v. sa1: d=1.3; and nz v. sa2: d=1.0). the sa groups performed better than the nz group in passing for accuracy over 4 m, but only with a small practical significance (d=0.3). in three tests, i.e. ground skills, ground kicks and kick-off distance, the nz group outperformed both sa groups. discussion this study found that nz elite u/16 rugby players performed better than sa players in the anthropometric tests, physical and motor abilities tests and game-specific tests. in cases where the sa groups had higher scores than the nz group, the practical significant differences were low and therefore of questionable value. in particular, the nz players were heavier with larger girth measurements. in addition, the nz players were quicker than the sa players, possibly as a result of the superior explosive power (vertical jump test). 16 in the zig-zag run test, where speed plays an important role, the nz group also had quicker times than the sa group. pienaar and spamer 2 found that younger rugby players’ strength is not as developed as expected, which may be the reason for the poor performance of the two sa groups in this specific test component. a lack of compulsory physical education at south african schools may be a reason for this disadvantage. ethnicity may be a factor in the strength test, where maori, tongan and samoan rugby players develop earlier than their sa counterparts. 5 for the speed endurance test, where the nz group had the best test values, a factor that might have played a role was the fact that the nz group was tested at sea level, whereas the sa group was tested at high altitude (north-west province). anaerobic performance times are longer (poorer performance) at higher elevations, than at sea level. 17 with regard to game-specific skills, the nz group scored better in the kicking for distance, passing for distance, and kick-off for distance tests. this may be due to the fact that the nz group possesses more power (vertical jump), strength (flexed arm hang), and longer limbs (height). all these factors may have contributed to the nz players being able to kick and pass the ball further than the sa group. however, where accuracy was the determinant factor (passing for accuracy over 4 m and 7 m), the sa groups had better test values. in rugby, the above factors play an important role in talent identification, position development, and the selection of players for a team. if rugby players obtain the above average scores they show potential talent. 2 there may be a number of reasons why the nz group scored better in the game-specific skills. one reason is that new zealanders play rugby and take part in rugby development programmes from a very young age (4 years), compared with south africans, who start playing rugby at a later age (8 years). although morning grade (bulletjie) rugby started in the late nineties in south africa, this had no effect on the sa groups tested in this study. thus, it may be estimated that the nz group played rugby and participated in rugby clinics for an average of 4 years longer than the sa groups, which means that they had more time to develop their rugby-specific skills. another possible reason is that the nz and sa groups were tested approximately 7 years apart. the practical significant differences between the two sa groups were also found in the game-specific skills tests that were tested about 6 years apart (van gent tested in 2003 7 ). the elapsed time period between the test dates would have affected the scores of the game-specific skills. for example, the rugby ball would have travelled further distances as a result of technological development and training and coaching techniques would also have improved over this time. the nz group scored better in the side-step and air-and-ground skill tests. a number of factors could have played a role in this finding. for example, the nz group scored better in the speed and zig-zag run tests, therefore they are able to run themselves into better position to recollect the ball in the air-and-ground skill test, and performed better in the side-step test. however, this result should be interpreted with caution as the same tester did not administer the testing for both the nz and sa groups. the relatively low interrater reliability could have contributed to the difference in the scores of these tests. 18 in conclusion, south african rugby authorities should take cognisance of the areas where south african u/16 rugby players were outperformed by their new zealand counterparts, and consequently develop specific development programmes to address these shortcomings. references 1. singer rn, murphy m, tennant lk. handbook of research on sport psychology. new york: macmillan; 1993. 2. pienaar ae, spamer ej. a longitudinal study of talented young rugby players as regards their rugby skills, physical and motor abilities and anthropometrical data. j hum mov stud 1998;34:13-32. 3. spamer ej, winsley r. comparative characteristics of elite english and south african 18-year-old rugby-players with reference to game-specific skills, physical abilities and anthropometrical data. j hum mov stud 2003;45:187-196. 4. van der westhuizen d, winders j, dreyer l, spamer ej, eds. anthropometric, game-specific, physical and motor ability variables of 12-year old rugby players (new zealand and south africa). presentation delivered at the 2004 sport conference; 2004; brisbane. 5. du plessis dj. comparative characteristics of elite new zealand and south african u/16 rugby-players with reference to game-specific skills, physical abilities and anthropometric data. masters dissertation in movement education. pretoria: university of pretoria; 2007. 56 sajsm vol 21 no. 2 2009 sajsm vol 21 no. 2 2009 57 6. hare e. die identifisering van rugbytalent by seuns in die senior sekondêre skoolfase (the identification of rugby talent in boys in the senior secondary school phase). med dissertation in afrikaans: potchefstroom university for christian higher education; 1997. 7. van gent mm. a test battery for determination of positional requirements in adolescent rugby players. masters dissertation: potchefstroom university for christian higher education; 2003. 8. norton ki, olds ts, olive sc, craig np. anthropometry and sport performance. in: norton ki, olds s, eds. anthropometrica: a textbook of body measurements for sports and health courses. sidney: unsw press; 1996. p. 287-364. 9. american alliance for health physical education and recreation (aahper). aahper skills test manual for football. washington: aahper; 1966. 10. thomas jr, nelson jk. introduction to research in health, physical education, recreation and dance. campaign: human kinetics; 1985. 11. hazaldine r, mcnab t. fit for rugby. london: kingswood press; 1991. 12. australian rugby football union. australian rugby skills test. sydney: australian rugby football union; 1990. 13. cooke g. rugby union. london: black; 1984. 14. sas institute. sas/stat user’s guide statistics. cary: sas institute; 1991. 15. cohen j. statistical power analysis for behavioural sciences. hillsdale: erlbaim; 1988. 16. foran b. high-performance sports conditioning. london: human kinetics; 2001. 17. mcardle wd, katch fi, katch vi. exercise physiology. lippincott: williams & wilkins publishers; 2001. 18. baechle tr, earle rw. essentials of strength training and conditioning. champaign: human kinetics; 2000. original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license the perceived knowledge of the menstruation cycle and adjustment of swimming sets by swimming coaches based on menstrual-related issues n marais, mphil; h morris-eyton, dphil; n janse van rensburg, phd department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa corresponding author: n janse van rensburg (natashajvr@uj.ac.za) menstruation is the term used to describe the recurring discharge of the endometrial lining of the uterus as menstrual blood and tissue.[1] menstruation, however, is only one of several events that occur during what is known as the menstruation cycle. [2] the menstruation cycle is the time interval (counted in days) from the start of one menstruation to the start of the following menstruation, [3] and may vary in length depending on the individual. regardless of the variability, normal cycles range from 21 to 34 days by the third year of menarche, [2] with the average length between cycles being 28 days. [1] although the constant change in hormone levels during the menstrual cycle is not visible, the effects of these changes can be felt by those who menstruate. the period itself may be expected to bring about the most discomfort, due to the discharge of blood and the use of menstrual hygiene products such as tampons, menstrual cups, or sanitary pads. it is, however, during the days prior to menstruation that women report feeling the most discomfort due to pain, heaviness, fatigue, irritability, and lack of concentration. [4] although the constant change in hormone levels combined with premenstrual syndrome (pms) may become a part of everyday life for the general female population, it is important to examine whether these symptoms influence the female athlete during training and competition. current national and international studies have attempted to understand and gain more insight regarding menstruation [5] and have also attempted to determine the perceptions about menstruation from males and females [5]. however, research on the physical and emotional symptoms that women experience when menstruating and the effect that these symptoms have on sport performance is lacking. the unique physiology of female athletes may require tailored training approaches that differ from those of their male counterparts. [6] female physiology, such as menstruation and its relationship to training, have been discussed among female athletes and coaches in practice. [6] since 2016, the world has begun to embrace the distinction between the sexes in sport, implying that men and women should be trained differently, based not only on hormone types and levels, but the respect of the emotional and physical effects that hormonal fluctuations can cause. [6] a study by bruinvels et al. [7] found that more than half of elite female athletes in various sporting codes reported that their hormonal fluctuations during menstruation had a negative impact on their performance in training and competition. yet ihalainen [6] indicates that olympic gold medals have been won by elite female athletes while menstruating during competition. research by bruinvels et al. [7] supports that of martin et al. [8], having found that 77% of female athletes experience negative side effects, such as pms symptoms, due to menstruation. these physical symptoms include back pains, cramps, headaches, and bloating. [8] this is further supported by oosthuyse et al. [9] whose findings indicated that fluctuations in strength, metabolism, inflammation, body temperature, fluid retention and injury risk are associated with hormonal fluctuations during a female athlete’s menstrual cycle. however, it has been noted that little is known about how menstrual cycle-related side effects may or may not affect the female athlete’s performance, and how these effects differ between individuals. [8,9] the potential effects of hormonal fluctuations throughout the menstrual cycle on various types of training and adaptations thereof are as follows: background: menstruation is the recurring discharge of the endometrial lining of the uterus as menstrual blood and tissue. the menstruation cycle affects most adolescent females and, although largely overlooked, affects women participating in sports. objectives: the aim of this study was to determine whether coaches were aware of their swimmers’ menstrual cycles and whether coaches considered this information when adjusting training sets. methods: within the case study, a partial mixed-method, sequential dominant status approach was used. data were collected in the form of questionnaires, focus group discussions, and one-on-one interviews. coaches’ awareness of their female swimmers’ menstrual cycles was based more on observation than communication from the swimmer. results: coaches explained that training is adjusted based on their observations, but whether this is being done correctly during the menstrual cycle requires more research. swimmers and coaches alike seem to have minimal knowledge of menstruation, its effects on training, and how to adapt to, or overcome, those effects during training or competition. conclusion: in future, this knowledge could ensure the longevity of female swimmers in the sport. understanding whether coaches and swimmers recognise the effect of the menstrual cycle within training and competition provides a more inclusive approach to ensure athlete longevity after puberty. this approach is grounded in creating an understanding between the swimmer and coach about the effect of menstruation during training and competition. it ensures an extended and more successful participation which may also assist in dealing with the ‘taboo’ surrounding menstruation and the female athlete. keywords: adolescent swimmers, swimming coach, female swimmer, swimming training, prescription s afr j sports med 2022;34:1-6. doi: 10.17159/2078-516x/2022/v34i1a13851 mailto:natashajvr@uj.ac.za http://dx.doi.org/10.17159/2078-516x/2022/v34i1a13851 https://orcid.org/0000-0002-2803-6940 https://orcid.org/0000-0001-8282-6196 https://orcid.org/0000-0003-1232-8233 original research sajsm vol. 34 no.1 2022 2 the follicular phase during the early follicular phase (days 1 to 7 of the menstrual cycle), the female body is primed for high intensity exercise due to increased pain tolerance and higher perceived energy levels. [6] however, during the late follicular phase (days 8 to 13 of the menstrual cycle), the rise in oestrogen hampers preexercise carbohydrate storage and therefore endurance female athletes experiencing this phase should increase carbohydrate intake the day before and during exercise to exercise at high intensities. [10] it has also been suggested that strength training may be more effective during the late follicular phase (days 8 to 14 of the menstrual cycle or until ovulation). [10] ovulation during ovulation (approximately day 14 of the menstrual cycle), it is suggested that maximum strength could be achieved during menstruation rather than during ovulation [11]. according to hansen et al. [12], increased risk of injury in young active females may be due to a physiologically high concentration of oestrogen, which reduces fibrillar crosslinking and enhances joint laxity. no research has specifically noted increased swimming injuries during ovulation. the menstrual cycle is part of a bigger health issue for female athletes. low energy availability because of unbalanced energy intake and expenditure, which can be due to overtraining or eating too little, can lead to irregular periods, amenorrhea, or problems with bone health. [6] according to mountjoy et al. [13] relative energy deficiency in sport (red-s) affects, among other factors, menstrual functions in athletic girls, which also relates to the medical condition referred to as the ‘female athlete triad’. the prevalence of menstrual disorders in sports, such as swimming, ranges from 16% to 82%. [14] previous studies have found that female swimmers appeared to be more vulnerable to delayed puberty and menstrual irregularities because of inadequate body fat stores and exercise stress. [14] by understanding the emotional and physical effects of the menstrual cycle, it may be possible to determine at which stage training should be adjusted to optimise performance, based on the needs of the female athlete. the correct maintenance of training around the menstrual cycle could possibly assist in attaining peak performance and encourage female athletes to extend their participation in sport. swimmers and coaches alike seem to have minimal knowledge of menstruation, its effects on training, and how to adapt to or overcome these effects during training or competition. therefore, the aim of this study was to determine the female swimmer’s and swimming coaches understanding of the menstruation cycle and whether coaches considered this information when adjusting training sets. methods a partially mixed method, concurrent dominant status (qual + quan) design approach was used. this allowed a deeper understanding of menstruation from coaches and to give the participants a voice. data were collected concurrently with the semi-structured interviews (swimmers and coaches) being done during the same time as the distribution and collection of the questionnaires. questionnaires were completed by coaches and swimmers. they were either self-administered paper questionnaires or completed online. theoretical framework the study was underpinned by brofenbrenner’s 1979 ecological systems theory (est) which was originally developed to focus on childhood development, examining how different environmental systems influence the development of an individual. this could be translated into the sporting environment and the athlete’s development within a particular sporting code. the est explores the individual within a community, and the relationships that take place between them [15]. it is through the community that the individual interacts. although swimming is considered an individual sport, it takes a community to organise and develop a swimming programme. coaches work closely with the athletes and parents, as well as the club, district, and provincial structures within the national federation (swimming south africa). it can be assumed that in the development of the athlete, each of these systems have an important role to play, with coaches being an influential component in the athlete-coach relationship. the athlete-coach relationship is pivotal in this research, as sharing issues regarding the effects of menstruation on training and performance requires trust, respect, and confidentiality. [16] the primary responsibility of a coach is to assist their athletes with training and competition performance outcomes, as well as recognising the emotional and physiological state of the athlete. [16] understanding that swimming coaching is embedded within a national federation system (swimming south africa), supporting female athletes will provide opportunities to facilitate talent and athlete development. ethical clearance ethical approval for the study was obtained from the university of johannesburg’s faculty of health sciences research and ethics committee (reference: rec-01-179-2018). permission to conduct the study was obtained from the head coach of the swimming school. participation in the questionnaires were anonymous. the identities of the participants who participated in the interviews were kept confidential. coaches were not informed of which swimmers or coaches took part in the study nor were they made aware of any responses received by swimmers or other coaches. as per the declaration of helsinki the wellbeing of participants took precedence over the research outcomes. participants volunteered and were allowed to leave the study without consequence. consent and assent were received in writing once participants had been made aware of what the research entailed, allowing participants to freely agree to take part. participants the swimming coaches were sampled on a voluntary basis. the coaches had to be coaching in south africa and coaching adolescent female swimmers who had already begun their menstrual cycles. the group of swimmers was purposefully sampled by meeting the following criteria: registered swimmers with swimming south africa, had already begun original research 3 sajsm vol. 34 no.1 2022 their menstrual cycle and had to be between the ages of 13 and 18-years-old. the five swimmers that took part in the focus group discussion/interview were registered with central gauteng aquatics (cga) as competitive swimmers and were coached by the same coach. recruitment method an email requesting voluntary participants was sent to the head coach of the club. the coach was then requested to forward the information to the parents of the adolescent females of menstruation age. if swimmers were then willing to take part in the study, their parents were requested to contact the researcher directly. the researcher’s details were provided in the email. once the researcher had received contact from the parents of willing swimmers, consent and assent forms were sent to the parent and/or guardian. quantitative data the coaches’ questionnaire was developed and adapted from johnson.[17] the swimmer’s questionnaire was based on similar questions in the coaches’ questionnaire and was restructured to contextualise the swimmer. the menstrual health section of the questionnaire was developed and adapted from hendrix (2010). [18] validity was ensured by asking the relevant questions and determining whether the questions reflected the perceptions and knowledge of menstruation. swimmers focus group and interview swimmers participated in one focus group and one interview conducted by one researcher. no parents or coaches were present during the interview allowing the participants to feel relaxed and open to the discussion. focus groups were initially planned with a group of five swimmers. unfortunately, due to unforeseen circumstances only three swimmers were available on the day the focus group discussion was scheduled. the remaining two participants were interviewed separately. coaches’ interviews semi-structured interviews were used to determine the coaches’ perspectives regarding the effects of menstruation on the female athletes they were coaching. there were six primary questions asked which were developed from the data collected from the coaches’ questionnaire. two coaches were interviewed face-to-face by the researcher and four coaches were interviewed using the zoom online platform, due to the limitations imposed by the covid-19 pandemic. data collection the quantitative data were collected from may 2019 to may 2020. the coaches’ questionnaire consisted of 14 questions and there were responses from 31 coaches. the swimmer’s questionnaire consisted of 18 questions and 25 swimmers responded. five swimmers took part in the semi-structured discussions, in which three questions were asked: (1) how do you usually feel when you have your period? (2) do you think it affects your training? and (3) would you discuss how you feel with your coach? the final phase of qualitative data collection was carried out by interviewing the swimming coaches. the semi-structured interviews were used to determine the coaches’ perspectives and consisted of six questions developed from the coaches’ questionnaire. once all qualitative data had been collected, findings, including field notes and voice recordings, were transcribed to organise the data for analysis. data analysis after the questionnaires had been completed, separate excel spreadsheets of findings from the coaches’ and swimmers’ questionnaires were created to organise the findings. the data were analysed using spss (version 26.0). descriptive statistics and thematic coding of the qualitative data provided the analytical information from the data collected. although quantitative and qualitative data were collected and analysed separately, the objectives of both were similar and therefore integrated into the results and discussion. data from the transcripts were divided into categories which were made up of different codes and sub-codes. the following categories were used for the swimmer focus groups and interviews: (1) athletes’ perception of their period, (2) athletes’ perception of the effects of menstruation on training, and (3) athlete and coach relationship. categories used for the individual coaches’ interviews included: (1) coaches’ awareness of swimmer’s menstruation, (2) swimmer-coach relationship (indicating that swimmers initiated the discussion around menstruation or menstrual-related issues with the coach), (3) accommodating the needs of the swimmer in training, and (4) coach-swimmer relationship (this indicates that the coach initiated conversations around menstruation or menstrual-related issues with the swimmer). categories were determined by the overall themes of the swimmers, menstruation, coaches, and their relationships. coding was done by one researcher and an independent coder who had no previous knowledge of the study. all themes, categories and codes were agreed to by the research team. results demographics twenty-five female swimmers participated in both the qualitative and quantitative parts of this study. of those swimmers three were 13-years-old, six were 14-years-old, four were 15-years-old, one was 16-years-old, nine were 17-yearsold and two were 18-years-old, respectively. the swimmers had a mean age of 15.5 years, with a standard deviation of 1.7 years. the majority (52%) of the female swimmers were south african national junior (sanj) swimmers, 12% were level 3 swimmers, 20% level 2 swimmers, and 12% were open water swimmers, with one swimmer not providing her swimming level. a total of 31 coaches completed the coaches’ questionnaire, of whom six coaches additionally took part in the semi-structured one-on-one interviews. of the 31 coaches, 18 were self-identified females and 13 were self-identified males. in addition to the questionnaire, the six coaches who took part in the interviews comprised three males and three females. original research sajsm vol. 34 no.1 2022 4 awareness three questions in the swimmer’s questionnaire highlighted the coaches’ awareness as follows: (1) is your coach aware of when you menstruate? (2) does your coach ask you when you started menstruating?, and (3) does your coach speak to you about menstrual-related issues/topics? most of the swimmers (20 of the 25) indicated that their coach was not aware of when they were currently menstruating. while 19 of the 25 swimmers indicated that their coach does not ask when they started menstruating, and 18 stated that they do not discuss menstrual-related issues with their coaches. however, the majority (20 out of 31) of the coaches indicated that they make a point of asking if their swimmer has reached menarche. when asked if they are aware when their swimmers are menstruating, 87% of the coaches stated that they are aware of when their swimmers are currently menstruating. consideration and training set adjustments of the five swimmers who said that their coach was aware of their menstruation, three admitted that their coach does accommodate them during training when they are menstruating by being more patient and sympathetic or by making the training session easier. two of the girls said that their coach did not accommodate them. all but one of the coaches said that swimmers request to withdraw from swimming training or competition because of menstrualrelated issues; however, only 22 coaches consequently allowed their swimmers to withdraw. in addition, most of the coaches (30 out of 31) believed that the menstrual cycle has the potential to influence sports performance, but only 22 stated that they changed their expectations of the swimmer if they became aware that she is menstruating or suffering from menstrual-related issues. when asked, only 18 of the coaches were willing to adjust training sets if their swimmer is menstruating or suffering from menstrual-related issues. during the interviews, the majority (five out of the six) of the coaches said that they only adjust training sets if the swimmer is experiencing severe signs or symptoms of premenstrual syndrome or menstruation, such as ‘heavy periods’ and ‘high pain levels’. three of the coaches further mentioned that they will stop the training session if the swimmer is not coping. two of the coaches, both female, mentioned that they do not adjust sets and avoid drawing attention to the swimmers if they are menstruating. discussion perceptions, awareness, and knowledge around menstruation and the menstrual cycle varied between coaches and swimmers. swimmers do not believe that their coaches are aware of their menstruation, while coaches believe that they are. this contradiction highlights the fact that the coaches’ awareness of their swimmer’s menstruation was based more on assumption than determining the facts. the lack of communication and knowledge regarding the female athlete’s state for training and competition compromises the strength of the coach-athlete relationship. when exploring awareness of menstruation and menstrualrelated issues, the swimmers’ and coaches’ results varied, reflecting different perceptions among the two groups. when coaches were asked about their awareness of their swimmers' menstruating, only fourteen indicated that the athlete made them aware of this, while the majority of swimmers indicated that their coaches were not aware of their menstruation status. in addition, nineteen of the swimmers stated that their coach does not ask them about menstruation or menstrual-related issues. the coaches' answers in the questionnaire highlighted an opposing opinion of the relationship, where twenty of the coaches indicated that they had an open discussion with their swimmers in which they asked them whether they had started menstruating. however, when interviewed, all the coaches said that they do not ask their swimmers about menstruation or menstrual-related issues only speaking about the topic if the swimmer approaches them about it. research conducted by johnson [17] found that 0.7% to 1.5% of coaches of various sporting codes asked their athletes about menstruation. the data obtained from the one-on-one interviews concur with this result. this necessitates a need to be a clear understanding between swimmers and coaches that menstruation does not imply weakness or that the periodised training plan needs to change. it is, however, an opportunity for the coach to track whether they are meeting the training needs of their female athletes to optimise training for the individual. in general, the research is inconclusive and there are mixed reviews regarding the menstrual phases and their effects on performance. [8,9] most females experience signs and symptoms of pms, which can hamper an athlete’s performance. the pms symptoms that the athlete experiences can make them hesitant to train or not want to train. [19] this should not be seen by coaches as a weakness in the athlete but rather as an opportunity for the coach to adjust training sets within the periodisation plan, such as working the athlete harder when they are not experiencing pms symptoms and using the days when the athlete experiences their pms symptoms as an opportunity to work on technique or recovery. not only will the athlete be more willing to train, but the approach will be more inclusive, giving the athlete a psychological edge (the mental advantage of not being discouraged by their menstruation or pms, e.g. the athlete will be willing to train with or without pms symptoms) and enabling their training sessions to work for them rather than against them. speaking openly about the menstrual cycle should not be viewed as taboo or embarrassing or used as an excuse to avoid training. rather it should be used to increase knowledge, empowering both the coach and the athlete. open communication allows coaches and athletes to avoid early signs of red-s from not tracking the menstrual cycle. [19] it will also assist coaches to monitor and track their female athletes, which, in turn, may encourage lifelong participation in sport and help an athlete progress in their sport as needed. [19] communication between the coach and swimmer may assist in minimising the assumptions made by coaches about pms symptoms experienced by athletes. without assumptions, the coach can cater more accurately to the athlete’s needs, making the coaching process more individualised, considering all aspects of training, not just the programme and the competitions. original research 5 sajsm vol. 34 no.1 2022 consideration was given regarding whether coaches were aware of information concerning the swimmer’s menstrual cycles before exploring whether adaptations or adjustments were made by coaches to training sets based on the swimmer’s menstrual signs and symptoms. although coaches claimed to be aware of a swimmer’s menstruation patterns, many swimmers indicated that coaches were not aware of this information. further investigation through the interviews revealed that coaches do not ask and are not told by the swimmers about their menstrual cycles. rather, awareness of their swimmer’s menstruation cycle is based on assumptions, such as the age of the swimmer or complaints of headaches, cramping and fatigue. although these are all signs and symptoms of pms, many other factors, such as illness, intense exercise, and dehydration can induce the same signs and symptoms. with the age of menarche continuously shifting and based on many factors, coaches can no longer use age as a defining factor that a female has in fact reached puberty. according to the swimmers, if the coach was aware of their menstruation (five girls reported that their coaches were aware), only three of the five coaches accommodated the swimmer. it was, however, highlighted that accommodating the swimmer was not necessarily done by adjusting training sets, but rather by the coach being supportive and understanding of the swimmer’s circumstances. however, the coaches who answered the questionnaire gave a different interpretation. most alluded to accommodating the swimmer and adjusting sets by making the sets shorter or less intense, or by letting the swimmer leave the pool if they were not coping in the training session. this contradicts the findings of johnson [17] in which none of the coaches responded that they shortened sets or decreased their intensity for their female athletes experiencing menstrual-related issues. only 0.8% of the coaches in johnson’s [17] study worked out a plan to enable the athlete to cope during menstruation, and 4.6% allowed the athlete to decide whether they could train or not; however, approximately 40% of the coaches were empathetic. the difference in results could be due to the coaches in johnson’s study coaching athletes at different school levels, whereas in this study, only registered competitive club swimmers were considered. if coaches are more aware of their swimmers' menstrual cycles, they can periodise training and adapt their training sets in a way that would be beneficial to the performance of the swimmer. stopping a set, decreasing the volume, or decreasing the intensity may not necessarily be the correct measure to put in place when a female swimmer is struggling with premenstrual or menstrual signs and symptoms. although no significant effects of the menstrual cycle on performance have been recorded, some studies have shown that strength training, endurance sets or anaerobic sets at various phases within the menstrual cycle are beneficial to female athletes. [9,10] muscle strength and muscle diameter have been shown to be increased during follicular phasebased strength training, more so than in luteal phase-based strength training, suggesting that strength training should be done during the follicular phase of the menstrual cycle [10]. however, oosthuyse et al. [9] found that endurance performance increased during menstruation and therefore athletes should be trained in the mid-luteal phase of the menstrual cycle. whereas pestana et al. [20] found no difference in anaerobic performance between the luteal and follicular phase; however, they noted that maximum heart rate was significantly lower in anaerobic performance during the midfollicular phase. with that in mind, coaches would have an advantage if they planned their training sets according to their female athletes’ menstrual cycle. practical applications communication between the swimmer and the coach is essential for the correct periodisation and training to maximise performance. guidelines to assist with non-invasive and open communication include: 1. a blank monthly calendar in an online format (such as google docs) that is accessible to the coach and swimmer. the parent can be included, especially with swimmers who are minors. 2. educating the swimmers on how to track their menstrual cycles. for example, marking the day their period starts and the day their period ends on a calendar. 3. educating the coaches about the phases of the menstrual cycle according to what their swimmers have marked on the calendar. 4. educating the coaches about the type of training that is most effective during each phase. 5. explaining to the coach that they need to look for red flags, such as the absence of swimmer’s period over an extended time, or if the swimmer’s period is shorter each month. 6. the swimmer could supply other information, such as signs and symptoms, using journals or notes on calendar days, if they are willing. the guidelines proposed above allow coaches to be aware of the swimmer’s menstrual cycle without the swimmer having to verbalise this information to the coach. to protect the swimmer’s privacy, consent for this would be given by the parent and assent by the swimmer. the document would also need to be password-protected to ensure that no one other than the three parties have access to the document. limitations and recommendations female swimmers and the effects of menstruation cannot be generalised as each individual’s experience of the menstrual cycle may be different. this is an indication that each athlete should be treated and trained using an individualised tailored approach, especially in individual sports such as swimming and running. coaches and athletes need to speak openly about menstruation, its effects and how to deal with it. by tracking the athlete’s menstrual cycle, the coach and athlete become more aware of the female physiology, ensuring that overtraining does not take place and giving the coach and the athlete an opportunity to work with the athlete’s menstrual cycle, rather than against it. future research should include larger sample sizes from more swimming clubs across south africa. contraception use was not factored into this study, and it may original research sajsm vol. 34 no.1 2022 6 have an influence on hormones and the swimmer’s experience of her menstrual cycle. for future research, it is recommended that contraceptive use versus no contraceptive is considered. the swimmer’s sporting career and how long they had been swimming were also not considered and could be beneficial for future studies to determine whether the duration of an athlete's career may affect their experience and perception of their menstrual cycle. conclusion coaches and swimmers alike seem to have minimal knowledge regarding menstruation, its effects on training, and how to adapt to and/or overcome those effects during training or competition. although the majority of the coaches adjust training sets if their female swimmers are experiencing menstrual related issues, how these adjustments are made and their effects on performance require more research. having an enhanced understanding around the menstrual cycle and its effects on the female athlete could increase the longevity of swimmers within the sport. it would also allow for better swimmer management related to training and competition. understanding whether coaches and swimmers recognise the effect of the menstrual cycle within training and competition provides a more inclusive approach to ensure athlete longevity after puberty. this approach is grounded in creating an understanding and developing a trusting relationship between the swimmer and coach regarding the effects of menstruation during training and competition. it may also ensure an extended and more successful participation in swimming, as well as assist in dealing with the ‘taboo’ regarding menstruation and the female athlete. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: nm: conception, design, analysis, and interpretation, drafting article, critical revision of the article, final approval for publication. hm-e: conception, design, critical revision of the article, final approval for publication). njvr: analysis and interpretation, critical revision of the article, final approval for publication. references 1. oertelt-prigione s. immunology and the menstrual cycle. 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[doi:10.1080/2159676x.2021.1941211]. 17. johnson tr. knowledge and attitudes regarding the menstrual cycle, oral contraceptives, and sport performance: the conceptualization and development of a questionnaire for athletic coaches 2008. florida state university. retrieved from http://purl.flvc.org/fsu/fd/fsu_migr_etd-3497. 18. hendrix sl. menstrual history & activity/diet questionnaire. west county spine & joint chiropractic clinic, 2010. available from http://www.westcospineandjoint.com/wp-content/uploads /2010/10/menstrual-history.activity.dietquestionnaire.2.24.15.pdf (accessed 1 october 2020). 19. nixon h, hendricks s, zondi p, et al. the female athlete webinar: the menstrual cycle, contraception, and relative energy deficiency in sport (red-s), 2020. available from https://www.youtube.com/watch?v=r155fj4apki (accessed 15 september 2020). 20. pestana er, salvador ep, pereira gb, et al. influence of the midfollicular and late luteal phases on anaerobic power in university students. sport sci health 2017;13(2):281-286. [https://doi.org/10.1007/s11332-016-0344-3] introduction injury to the spinal cord during rugby is rare but remains an emotionally charged issue, especially at schoolboy level. quarrie et al. 1 report an overall 1.4 spinal cord injuries per annum per 100 000 new zealand rugby players. this has reduced to 0.7 since 2001. this reduction corresponds with the introduction of a local education programme but may also have to do with the change of scrumming laws. 2.3 previously many of the injuries were incurred in scrumming, but with law changes the average number of scrums per game has reduced by 40%. now many spinal cord injuries occur during open play and particularly during the tackle. fuller et al. 4 followed 12 english premiership clubs for two seasons and found an incidence of 10.9 spinal column injuries per 1000 player match hours. none were catastrophic, but 3 were career ending. he confirmed tackles as the major culprit. in the south african context, noakes et al. 5 reported a total of 8.3 spinal cord injuries per season during 1990 1997 in the western cape alone. twenty per cent were schoolboys. the devastating outcome was death in 8%, tetraplegia in 48% with only 35% recovering significantly. efforts to make the game safer include law changes as well as player, coach and referee education. in addition, early recognition and appropriate management of the spinal cord injury are mandatory. injury to the spinal cord not only results in motor and sensory loss, but also autonomic dysfunction, which results in the body’s inability to regulate blood pressure, pulse and temperature. breathing efforts are compromised by loss of voluntary muscle control and these factors threaten the patient’s life. the initial management revolves around injury recognition, minimising secondary spinal cord injury, support of essential physiological functions, and avoidance of related complications. definitions • cervical – neck. • complete spinal cord injury (sci) – total loss of spinal cord function at a given anatomical level. • dermatomes – the area of skin that is supplied by a specific nerve. • incomplete sci – partial loss of spinal cord function at a given anatomical level, with residual sensory or motor function distal to the lesion. • neurological – relating to the nerve function. • paraesthesia – a sensation of ‘pins and needles’ in the distribution of the nerves affected. this may be confined to one region of one limb if a single nerve is involved to diffuse involvement of both or all limbs. • paraplegia – complete loss of motor (power) function in the lower limbs, i.e. legs, with preservation of normal upper limb function, if the spinal cord is involved. • prognosis – future clinical outcome. • spinal cord injury (sci) – damage to the spinal cord which manifests in a loss of motor and/or sensory function. • tetraplegia – complete loss of motor (power) function in both upper and lower limbs. • thoracic – torso. clinical review boksmart: medical management of suspected serious acute spinal cord injuries in rugby players abstract injury to the spinal cord with paralysis during rugby is rare but remains an emotionally charged issue, especially at schoolboy level. the game has evolved over the years with rule changes to reduce injury risk. scrums were originally perceived as the high-risk phase of play and rule changes in the early 1990s have reduced the number of scrums per game by as much as 40%. over time the ferocity of play has also increased with bigger, fitter players and possibly more at stake with professionalism. catastrophic injury rates are low but still occur. although risk and injury cannot be totally avoided in a contact sport, it does appear that there are deficits in the management of this risk and subsequent injury. sa rugby has introduced an educational programme (boksmart) to increase the level of understanding by players and support staff. this article was prepared for the boksmart programme in an effort to highlight the deficits and provide a basic understanding of spinal injury. terminology, diagnosis and appropriate investigations are dealt with. the early emergency management is discussed as would occur at the first medical point of contact. this allows standardisation of injury assessment so communication between personnel is clear. an algorithm has been suggested to provide an appropriate management strategy should an injury occur. correspondence: dr robert dunn po box 30086 tokai 7966 cape town tel: 021 404-5387 e-mail: info@spinesurgery.co.za robert n dunn (mb chb, mmed (orth), fcs(sa) orth) spine surgery unit, division of orthopaedic surgery, university of cape town sajsm vol 21 no. 3 2009 91 diagnosis the diagnosis is made on the basis of clinical assessment and special investigation. the initial evaluation is made on the field when a player complains of neck or back pain with associated neurological symptoms. significant cervical or thoracic pain with focal tenderness of palpation of the spinous processes and a restricted range of cervical motion suggests a significant spinal injury. neurological symptoms may be as subtle as paraesthesia (pins and needles) in the limbs to loss of sensation and motor function. a complete neurological examination by a doctor is required to ascertain whether there is in fact neurological compromise and, if so, to what degree. this requires testing of all dermatomes for sensation and appropriate muscle groups for power. the presence of a sensory level is delineated in the case of a sci. this manifests at a skin level where there is normal sensation proximal (towards the head), whereas distal (towards the feet) it is altered or absent. the patient is log-rolled and a rectal examination done to confirm the presence or absence of peri-anal sensation, anal tone and voluntary sphincter function. should this be absent the sci is regarded as complete as there is no residual cord function below the lesion. should any of these be present, the lesion is incomplete, with a better predicted outcome (prognosis). the interpretation will be dealt with in the section on grading of injury. the patient should be medically stabilised before further investigation, as discussed below. the first special investigation is x-ray. commonly the injury is to the cervical area. this can be localised both on the location of the pain and the anatomical lesion from the clinical examination. a cervical x-ray series consists of an anterior-posterior view of the neck, an open-mouth view and a lateral view. the lateral view should extend from the base of the occiput to t1. should the distal spine not be visible due to the presence of the shoulders, it should be repeated with manual traction on the arms. failing this, a swimmer’s or flying angel view should be performed. the x-rays should ideally be assessed by a radiologist but often it is the treating clinician who is faced with the initial interpretation. the lateral view is the most useful but injuries can be missed in up to 30% of cases. a simple approach is to assess the 5 lines – 4 vertical and 1 of convergence (fig. 1): • soft-tissue line • anterior body line • posterior body line • spino-laminar line • convergence of the spinous processes. when viewing the soft-tissue line, there should be less softtissue shadow than half a vertebral body down to c6, with up to one body width acceptable below this (grey arrow). there should be a smooth, uninterrupted line running down the anterior aspect of the cervical vertebral bodies from c1 to t1 (white dashed). likewise for the posterior body line (white dotted) and spino-laminar line (green dashed). a disruption in any of these would suggest loss of spinal column integrity. the lines of convergence are drawn along the axis of the spinous process and should meet posterior to the neck. if they diverge an injury is suspected. the ap view should be assessed for a rotatory deformity. this is suggested should there be deviation of the spinous process from the midline. the spinous process is shown with the white arrow (fig. 2). should the x-rays be interpreted as normal and there is no neurological deficit, dynamic views would be indicated. this involves flexion or extension views where the patient is asked to maximally flex his neck forward and backwards and x-rays are taken at the extremes. the patient should not be assisted with movement as pain will limit this to within a safe zone. these x-rays are reviewed for 92 sajsm vol 21 no. 3 2009 fig. 1. normal lateral cervical x-ray depicting the 4 vertical lines of convergence used to assess loss of alignment.  fig. 1. normal lateral cervical x-ray depicting the 4 vertical lines of convergence used to assess loss of alignment. fig. 2. normal ap x-ray where the spinous processes can be seen in alignment.  fig. 2. normal ap x-ray where the spinous processes can be seen in alignment. signs of instability. this includes evidence of listhesis (forward slip) of 3.5 mm or more, kyphosis of greater than 11° and loss of the normal contours. in the case of neurological deficit a mri scan is required (if available). this is the only way the neurological and other soft-tissue structures can be visualised. it provides the information to make a confident diagnosis and plan safe treatment. occasionally, if an mri scan is not readily available one may be forced to manage certain injuries without it. this is a compromise and not the ideal. grading of injury the injury is graded in terms of two aspects, viz. the integrity of the vertebral column and the neurological status of the spinal cord. column integrity as regards the column integrity, it is essential to decide if the spine is stable or not. should there be evidence of instability the spinal cord is at risk, as the spine no longer has the ability of resistance to physiological forces. instability can be a result from bony or ligamentous injury. ligamentous injuries are more dangerous as they are not immediately visible on x-ray but suggested by change in alignment. this is more subtle than a fracture. cervical injuries are defined according to mechanism. this is a combination of compression or distraction forces in either flexion or extension as per the allan and ferguson classification. 6,7 the commonest injuries seen in the rugby context are the distractive flexion and burst injuries. the way the cervical spine is exposed to force rather than the specific event (tackle, scrum collapse) dictates this. a player can dive into a ruck, and depending how he strikes the ground can exert either a compression force or likewise, by striking his forehead and his body rolling over, create a distractive force on the neck. a compression flexion injury results in one of the vertebral bodies being fractured, i.e. collapsing. depending on the degree, this may be limited to deformation of the superior endplate of the body. should there be more force applied, the inferior anterior part of the body will fracture, creating the ‘teardrop’ fracture. despite appearing relatively innocuous on x-ray, this implies that the posterior ligamentous structures have been disrupted and the fracture is unstable. in the extreme case, the teardrop fractures right off, the body retrolistheses (moves backwards) through the spinal canal and transects the spinal cord. in distraction flexion injury, there is a stretching out of the posterior ligamentous structures, which include the interspinous ligaments and the facet joint capsules. this allows one or both the facet joints to dislocate. with this there is disruption of the anterior disc tissue, creating instability. should the injury be limited to a unifacet dislocation, the incidence of severe neurological injury is low. a bifacet (both facets) dislocation is evidenced by more than 50% body width anterior translation on the lateral x-ray, compressing the spinal cord, and resulting in a higher incidence of neurological injury. this type of injury is usually the one that requires urgent intervention as sci may be reversible once the compression has been relieved. neurological status it is important to classify the extent of the injury to be able to succinctly communicate to a referral centre, as it may affect management in the early phase. the american spinal injury association (asia) system is utilised. the assessment is based on determining the level and extent of the injury. the former requires knowledge of anatomy, but for ease, key muscle groups are marked on the asia chart (appended). muscle groups are examined and the level is based on the last normal function level, i.e. full power. once this is determined, residual distal function is sought. this may be an area just below the lesion, termed a zone of partial preservation, or maintained function throughout the rest of the body. the latter is far more important prognostically 8-10 because if there is sensation or motor function maintained distally, there is a much better chance of recovery. the lesion is deemed complete if there is no residual distal function and incomplete if function is present. care must be taken to assess voluntary motor function to command. sensation must be critically assessed by asking the blinded patient to indicate which leg is being touched as opposed to ‘can you feel’. the rectal examination is mandatory in this assessment. all this should be charted on the asia score sheet. the physician should be careful not to interpret anterior chest sensation as preservation of thoracic sensation, as the supraclavicular nerves from the cervical region can supply this area. once this assessment has been done, a neurological diagnosis of last functional level, zone of partial preservation (zpp) and complete/incomplete should be documented. preferred list of medical facilities it is important that every school or club determines an appropriate hospital in case of suspected spinal cord injury. facilities vary widely from region to region and access may depend on financial status of the patient. it is pointless taking a patient with no insurance to a private medical facility if the treating doctor is unable to access the expensive sajsm vol 21 no. 3 2009 93 1 yesno observe neuro and x-rays normal normal discharge inadequate due to pain collar and repeat in 10-14 days abnormal to be assessed by surgeon or doctor familiar with spine pathology mri if neurological deficit (not to delay management if dislocation present) further management based on particular fracture or dislocation as assessed by orthopaedic or neurosurgeon neck injury loss of full range of motion pain loss of motion / sensation pins and needles take to hospital clinical examination x-rays abnormal flexion / ext x-rays fig. 3. flow chart of management of an on-field neck injury. imaging modalities. this results in delays while the transfer of the patient to a state facility is arranged. the degree of spinal injury may dictate the level of care. should the patient complain of a painful neck but no complaints or evidence of spinal cord involvement, i.e. no paraesthesia or sensory disturbance and full voluntary muscle power, it is likely only x-rays will be required. there is also no extreme urgency in this case, so a stepwise approach can be adopted. this patient can then be taken to a facility where x-rays are available, but not necessarily mri. this is more applicable in the state environment as most private centres have an mri, but it may not be available on the weekends. the chosen hospital should be at least a level 2, with specialist staff available to interpret the x-ray. should there be any neurological symptoms, it would be best to attend a hospital with mri capabilities as well as spinal surgical resources. in the state service this may be limited to level 3 services such as in the western cape. it should be ascertained that the private hospital in the school’s vicinity has spinal surgical capabilities before utilising their services, in order to avoid delay. acute sci medical management protocol (fig. 3) once the injured rugby player arrives in hospital he is assessed by the treating physician. atls protocol is followed in terms of emergency management. as sci patients can be physiologically unstable, they are best managed in a high-care environment. a dedicated spinal unit is the best. continuous monitoring of physiological function is necessary with mechanical ventilation available. the patient should be well immobilised on a firm board to avoid secondary injury. the patient should be supine in a neutral position. should there be an obvious neck deformity, gentle in-line traction may be necessary for comfort and immobilisation. no forced movement should be performed and movement should be limited if there is associated pain. preferably a soft thin mattress should be between the board and the patient to prevent pressure sores developing. log-rolling, i.e. turning the body in unison, should be performed when examining the patient. this involves three personnel – one with a head grip, one on the shoulders and the other on the pelvis, avoiding any spinal torque when rotating the patient. this allows examination of the back of the neck and torso and facilitates pressure care. intravenous access must be obtained and fluids administered to maintain an adequate blood pressure. patients with sci lose their vascular tone, increasing capacitance, and they therefore develop neurogenic shock. they will only transiently respond to fluid resuscitation and this should be limited to avoid pulmonary oedema. cervical sci patients may not be able to respond with a tachycardia as there is disconnection of the spine and sympathetic plexus. a mean blood pressure of more than 70 mmhg is necessary to maintain cord perfusion and minimise the secondary injury. the use of adrenalin may be necessary. adrenalin 4 amps in 200 ml normal saline diluent can be infused, titrated against the blood pressure. typically this is infused at 3 10 drops/min (60 dropper). occasionally with high cervical lesions there is a higher requirement, necessitating a double-strength mixture, i.e. 8 amps adrenalin in 200 ml normal saline at 1 10 drops per minute. should there be a persistent bradycardia (<40 bpm), atropine 0.5 mg iv can be administered. the use of high-dose steroids is a management choice. there is little evidence of any clinically significant benefit and complication rates remain high. if the physician uses steroids, the nascis 3 protocol should be followed, i.e. 30 mg/kg depot medrol over 15 minutes followed by 5.4 mg/kg per hour for 24 hours if within 4 hours of injury and 48 hours if within 8 hours. after 8 hours, even the proponents see no benefit. 11 a urinary catheter should be placed to assess urine output as well as avoid complications from retention related to the sci. as these patients frequently develop an ileus, they are placed nil per os and a nasogastric tube is passed. these patients are at risk of gastritis, and ulsanic 1g 6 hourly should be administered per os or via the nasogastric tube. the patient should be assessed for respiratory difficulty. frequently patients with a high cervical lesion may fatigue with the increased efforts of diaphragmatic breathing and become hypercapnoeic. oxygenation is also challenged by atelectasis and possible pulmonary oedema. all patients should receive face-mask oxygen to maintain spinal cord oxygenation and if there is deterioration they should be supported by face-mask cpap or intubation in extreme cases. it is preferable to intubate early rather than await extensive atelectasis and pneumonia, as this will only prolong the course of ventilation. there is often reluctance to intubate these patients due to perceived poor prognosis, but it should be remembered that in the early phase of spinal shock, there is cord swelling or spinal shock and once this resolves there may be a dramatic improvement. the patient must be given the benefit during this period. 12 once the patient is stable physiologically, radiographic investigation is required to assess the injury. this will involve x-rays 94 sajsm vol 21 no. 3 2009 fig. 4. case 1. lateral x-ray confirming a c5/6 unifacet dislocation.  fig. 4. case 1. lateral x-ray confirming a c5/6 unifacet dislocation. . fig. 5. note the double mattress to allow extension of the neck after reduction.  fig. 5. note the double mattress to allow extension of the neck after reduction. as discussed above as well as an mri scan if there is neurological injury as well. a ct scan is indicated should there be a suspicious lesion on x-ray that requires further delineation. this is more applicable in the patient with a suspicion of vertebral column injury but no neurological injury. in the ideal world an mri is required to assess the sci. should this not be available the treating physician needs to decide whether to transfer the patient to another facility or proceed without an mri. this is a very complex and controversial argument. 13 if it is clear that the patient is deteriorating neurologically or has a neurological complete lesion and the x-rays confirm a dislocation, it would be reasonable to proceed with closed reduction. there is some weak evidence to suggest early reduction in bifacet dislocations improves outcome, so one would prefer not to delay. 14,15 in a patient with minimal neurological deficit and a dislocation, there is a risk of deterioration with closed reduction, 16 and a pre-reduction mri is preferable to exclude a disc herniation. 17,18 although rare, it is a cause for concern. should there be a fracture (compression teardrop), there is no reduction required but in-line traction with callipers will assist in realigning the spine. for both the dislocations and fractures, the head or neck can be immobilised with callipers. for the reduction process, one can start with 5 kg for the head and 2 kg per level, positioned in flexion and under x-ray control reduce the facets. the weights can be sequentially increased but seldom beyond 15 kg. once reduced, the weight can be reduced to 2 kg. a fracture can be maintained with 2 4 kg. 19,20 sajsm vol 21 no. 3 2009 95 fig. 6. this series of x-rays demonstrates the dislocated facet distracting, perching and finally reducing into its normal place. following reduction, an anterior c5/6 fusion was performed with a plate and iliac crest bone graft. this allowed discharge within a few days. an intra-operative open reduction and fusion would also be an acceptable option.  fig. 6. this series of x-rays demonstrates the dislocated facet distracting, perching and finally reducing into its normal place. following reduction, an anterior c5/6 fusion was performed with a plate and iliac crest bone graft. this allowed discharge within a few days. an intra-operative open reduction and fusion would also be an acceptable option. fig. 7. x-rays show teardrop fragment indicative of a compression flexion injury.the mri scan indicates increased signal in the fractured body and spinal cord. there is no persistent compression.  fig. 7. x-rays show teardrop fragment indicative of a compression flexion injury.the mri scan indicates increased signal in the fractured body and spinal cord. there is no persistent compression. fig. 8. x-ray confirms a c4/5 anterior listhesis and kyphosis. an urgent mri scan confirms the bilateral facet dislocation (see para-sagittal views) as well as significant disc behind the c4 vertebral body. this puts the cord at risk during reduction.  fig. 8. x-ray confirms a c4/5 anterior listhesis and kyphosis. an urgent mri scan confirms the bilateral facet dislocation (see para-sagittal views) as well as significant disc behind the c4 vertebral body. this puts the cord at risk during reduction. once reduced, the definitive management is surgical stabilisation if the skill is available. 21-25 the option of 6 weeks’ traction in bed followed by 6 weeks in an orthosis is a poor one. during the period there is risk of complications such as bed sores and pneumonia. 26 in addition, there may be instability at the end of treatment and surgery may be required in any event. should the mri confirm disc extrusion and thus risk of neurological deterioration with reduction, open (surgical) decompression and reduction can be performed from anterior with relative ease. the spine should be stabilised surgically either by an anterior plate or posterior fixation. chest physiotherapy should be instituted twice a day with assisted coughing. frequent suctioning should be performed. pressure care is mandatory with 3-hourly turns. the use of a pressure reduction mattress (e.g. huntleigh) is recommended in high cervical injuries. deep vein thrombosis prophylaxis is advised with ted stockings and a low molecular weight heparin (lmwh) such as clexane 40 mg or fragmin 5000u daily sc. examples case 1 (figs 4 6)) an 18-year-old male presents with a painful neck following a scrum collapse. his neurological examination is normal. his lateral x-ray demonstrates a listhesis (forward translation) of the c5 on c6 vertebral body. there is a breach in all the vertical lines and the spines are no longer convergent. on closer inspection, it is clear that one set of facet joints are dislocated. there is obliquity of the c6 facets compared with c5, suggesting a rotation between the two. the diagnosis is that of a unifacet dislocation. as there is no neurological deficit, closed reduction is an option. cones callipers were applied, initially in flexion, and serial weights were utilised. case 2 (fig. 7) a 19-year-old male presents with diffuse paraesthesia following injury. there is no need for reduction or decompression. the patient underwent an anterior fusion to re-establish stability. posterior fusion is an acceptable option. case 3 (fig. 8) this 25-year-old man presented with an incomplete cervical sci. as the patient was incomplete neurologically, urgent surgical intervention is indicated. an emergency anterior discectomy, open reduction and instrumented fusion was performed. acknowledgements the paper was commissioned by the boksmart programme, which is a national programme sponsored by absa and implemented on behalf of the south african rugby union and the chris burger/petro jackson player’s fund. the goal of the programme is to teach safe and effective techniques, which will reduce the incidence and severity of injury, make the game safer for all involved and improve rugby performance. references 1. quarrie kl, gianotti sm, hopkins wg, hume pa. effect of nationwide injury prevention programme on serious spinal injuries in new zealand rugby union: ecological study. bmj 2007:334;1150-1153. 2. silver jr. the impact of the 21st century on rugby injuries. spinal cord 2002;40:552-559. 3. quarrie kl, cantu rc, chalmers dj. rugby union injuries to the cervical spine and spinal cord. sports med 2002;32(10):633-653. 4. fuller cw, brooks jh, kemp sp. spinal injuries in professional rugby union: a prospective cohort study. clin j sport med 2007:17(1):10-16. 5. noakes td, jakoet i, baalbergen e. an apparent reduction in the incidence and severity of spinal cord injuries in schoolboy rugby players in the western cape since 1990. s afr med j 1999;89(5):540-555. 6. allan b, ferguson r, lehmann t, o’brien r. mechanistic classification of closed indirect fractures and dislocations of the lower cervical spine. spine 1982;7:1-27. 7. cusick jf, yoganandan n. biomechanics of the cervical spine 4: major injuries. clinical biomechanics 2002;17:1-20. 8. lintler dm, knight rq, cullen jp. the neurologic sequalae of cervical spine facet injuries. the role of canal diameter. spine 1993;8:775-779. 9. kenneth a, gerhardt ms. spinal cord injury outcomes in a population based sample. j trauma 1991;31(11):1529-1535. 10. frielingsdorf k, dunn rn. cervical injury outcome – a review of 101 cases. s afr med j 2007;97:203-207. 11. bracken mb, shepard mj, holford tr. methylprednisolone or trilazad mesylate administration after asci: 1 year follow up. j neurosurg 1998;89:699-706. 12. burns as, ditunno jf. establishing prognosis and maximizing functional outcomes after spinal cord injury: a review of current and future directions in rehabilitation management. spine 2001;26:s137-145. 13. jacobs r. mri preand post rapid heavy weight closed reduction. saoj 2006;5:40-48. 14. carlson gd, minato y, okada a, et al. early time-dependent decompression for spinal cord injury: vascular mechanisms of recovery. j neurotrauma 1997;14:951-962. 15. delamarter rb, sherman j, carr jb. pathophysiology of spinal cord injury. recovery after immediate and delayed decompression. j bone joint surg am 1995;77:1042-1049. 16. rizzolo sj, piazza mr, cotler jm. intervertebral disc injury complicating cervical spine trauma. spine 1991;16:5187-5189. 17. robertson pa, ryan md. neurological deterioration after reduction of cervical subluxation. mechanical compression by disc tissue. j bone joint surg br 1992;74:224-227. 18. vaccaro ar, falatyn sp, flanders ae, et al. magnetic resonance evaluation of the intervertebral disc, spinal ligaments and spinal cord before and after closed traction reduction of cervical spine dislocations. spine 1999;24:1210-1217. 19. lee as, maclean jc, newton da. rapid traction for reduction of cervical spine dislocations. j bone joint surg br 1994;76:352-356. 20. vital jm, gille o, senergas j, et al. reduction technique for uniand biarticular dislocations of the lower cervical spine. spine 1998;23:949-954. 21. keynan o, dvorak m, fisher c. reduction techniques in cervical facet dislocations. tech orthopaed 2003;17:336-344. 22. hadley mn, fitzpatrick bc, sonntag vk, et al. facet fracture-dislocation injuries of the cervical spine. neurosurgery 1992;30:661-666. 23. stathoutis b, govender s. the triple wire technique for bifacet dislocation of the cervical spine injury. vol. 28, nr. 2, pp. 123-125, 1997. 24. doh koh y, lim t, won you j. a biomechanical comparison of modern anterior and posterior plate fixation for the cervical spine. spine 2001;26:1521. 25. key ag, retief pj. spinal cord injuries. an analysis of 300 new cases. paraplegia 1970;7:243-249. 26. storm m, dunn rn. unifacet cervical fractures. saoj 2007; (spring):1422. 96 sajsm vol 21 no. 3 2009 original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license kinematic differences between leftand right-handed cricket fast bowlers during the bowling action b olivier,1 phd; n boulle,1 msc; j jacobs,1 msc; ol obiora,1 phd; c macmillan,2 phd; j liebenberg,1 msc; s mcerlain-naylor,3 phd 1 wits cricket research hub for science, medicine and rehabilitation, department of physiotherapy, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 sport exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa 3 school of sport, exercise and health sciences, loughborough university, united kingdom corresponding author: b olivier (benita.olivier@wits.ac.za) bowling is a critical aspect of cricket, where the bowler aims to restrict the runs scored by the opposing team. one way this is achieved is through fast bowling, i.e. maximising ball release speed and minimising batters’ response times. fast bowlers and their coaches consistently seek enhanced ball release speeds via more effective biomechanical bowling actions.[1, 2] for right-handed bowlers, this action consists of a run up to the bowling crease followed by landing on the right foot (referred to as back foot contact), stepping onto the left foot (front foot contact), and delivering the ball with the right hand (ball release) before following through onto the right foot again (follow through ground contact). the opposite is true for left-handed bowlers. laboratory-based (e.g. 3d motion capture [3]), field-based (e.g. inertial measurement units [imus][4]), and computer simulation[2] approaches have been used to investigate associations between bowling technique parameters and performance or injury incidence. each approach has advantages and limitations, with inertial measurement units enabling the measurement within an athlete’s habitual training environments and contexts. for example, senington et al.[5] used imus to investigate the relationship between spinal kinematics, lower limb accelerations, and ball release speed. greater sacral vertical acceleration loading rate at back foot impact and thoracic side flexion at front foot impact was associated with faster ball release speeds. similarly, imus have been used to establish the association between spinal kinematics, tibial impact, and low back pain in bowlers. those without a history of low back pain had more thoracolumbar rotation between back and front foot contacts and greater times to peak tibial acceleration following front foot contact.[4] most investigations into fast bowling biomechanics have either explored the optimal technique for right-handed fast bowling[2] or considered leftand right-handed bowlers within a single group.[3] kinematic differences have been reported between leftand right-handed players in other ball and bat sports, such as baseball pitching[6] and tennis.[7] any overrepresentation of left-handedness in sports compared to the general public[8] may be as a result of not only technical but also perceptual, tactical, or strategic factors.[9] knowledge of kinematic differences, such as those determined in this exploratory study, will form the basis of future research seeking to augment or counter the potential ‘unorthodox’ nature of the left-handed cricket bowling action. therefore, descriptive studies make up an essential part of the knowledge base. the aim of this study was therefore to compare the kinematics between leftand right-handed adolescent fast bowlers performing an equivalent bowling task. due to the exploratory nature of this study and the lack of previous literature, no a priori hypotheses were made regarding the possible kinematic differences between the groups. methods study design and setting this was a quantitative, cross-sectional study. data collection took place at the cricket nets of the respective schools. participants leftand right-handed injury free male schoolboy fast bowlers between the ages of 14 and 18 years participated in this study. all players played for their school’s cricket teams in a competitive high school league. bowlers were classified by background: despite differences between leftand righthanded athletes in other sports, minimal evidence exists regarding biomechanical similarities and differences between leftand right-handed cricket fast bowlers performing an equivalent task. objectives: this study aimed to compare the kinematics between left and right-handed fast bowlers performing an equivalent task (i.e. bowling ‘over the wicket’ to a batter of the same handedness as the bowler). methods: full body, three-dimensional kinematic data for six left-handed and 20 right-handed adolescent, male, fast bowlers were collected using the xsens inertial measurement system. time-normalised joint and segment angle time histories from back foot contact to follow-through ground contacts were compared between groups via statistical parametric mapping. whole movement and subphase durations were also compared. results: left-handed players displayed significantly more trunk flexion from 49%-56% of the total movement (ball release occurred at 54%; p = 0.037) and had shorter back foot contact durations on average (0.153 vs 0.177 s; p = 0.036) compared to right-handed players. conclusion: leftand right-handed bowlers displayed similar sagittal plane kinematics but appeared to use non-sagittal plane movements differently around the time of ball release. the kinematic differences identified in this study can inform future research investigating the effect of hand dominance on bowling performance and injury risk. keywords: biomechanics, dominance, handedness, laterality s afr j sports med 2023;35:1-8. doi: 10.17159/2078-516x/2023/v35i1a15144 mailto:benita.olivier@wits.ac.za http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15144 https://orcid.org/0000-0001-9287-8301 https://orcid.org/0000-0002-9745-138x https://orcid.org/0000-0003-4489-8214 https://orcid.org/0000-0002-5284-3208 https://orcid.org/0000-0002-2372-3645 https://orcid.org/0000-0003-3003-8870 https://orcid.org/0000-0001-9920-617x original research sajsm vol. 35 no.1 2023 2 their coaches as fast bowlers following the accepted definition of a fast bowler where the wicketkeeper stands back from the stumps against them.[10] the human ethics research committee (medical) at the university of the witwatersrand approved this study. all participants, and parents/caregivers of participants younger than 18 years, signed consent and assent forms, respectively, before data collection commenced. instrumentation and outcome measures three-dimensional biomechanical data were collected using an xsens inertial sensor motion analysis system (mvn link biomech, xsens technologies b.v., enschede, netherlands), a full-body human measurement system consisting of 17 imus recording at 240 hz, biomechanical models, and sensor fusion algorithms. the imus were placed on the posterior head, sternum, pelvis (middle of the two posterior superior iliac spines, posterior shoulders (centre of scapulae), upper arms, forearms, posterior hands, lateral thighs, tibialis anterior and the superior feet. they were securely positioned within a lycra bodysuit.[11] movement data were resolved via the mvn analyze software into the respective segment and joint kinematic data. in addition to joint and segment angles, triaxial acceleration was recorded via each imu. sagittal plane joint angles and non-sagittal torso-related angles from xsens mvn have been compared against a 3d marker-based motion capture system during the analysis of gait and reported excellent wave similarity for sagittal angles and frontal torsorelated angles, with very good to excellent similarity for transverse torso-related angles.[12] harnett et al[13] investigated the outputs between an optical motion capture and an inertial measurement unit during bowling in cricket and found a mean difference of 4.7° in the shoulder girdle relative to pelvis angle and no difference between the two systems in terms of trunk and knee angles (mean differences being 0.1° and 1.6°, respectively). cottam et al.[14] stated that the differences between inertial measurement units and optical motion capture output might lie in the inherent errors associated with an optical motion capture system and confirmed that inertial measurement units are valid in the measurement of dynamic, multi-planar movements, such as the cricket fast bowling action.[14] procedures anthropometric measurements of each participant were entered into xsens software for calibration purposes. these measurements included body mass, stature, foot length, shoulder height and width, arm span, hip height and width, knee height, ankle height and sole height. each bowler performed a five-minute self-selected warm-up in their accustomed manner. calibration was performed in the n-pose (arms neutral beside body) and during walking.[11] bowlers then bowled six match-paced deliveries using a 135g cricket ball. bowlers were instructed to bowl 'over the wicket' (i.e. right-handed bowlers bowled from the left of the wicket to a right-handed batter (figure 1d) and left-handed bowlers bowled from the right of the wicket to a left-handed batter (figure 1b) towards the top of off stump. the angles of release for left and right-handed bowlers are shown in figure 1. three-dimensional biomechanical data were recorded using the xsens analyze software. the number of successful, analysed, trials was 4 ± 1 for the six left-handed bowlers and 4 ± 2 for 20 right-handed bowlers. overall, 4 ± 2 trials were analysed for each of the 26 bowlers. data processing front foot contact was identified as occurring three frames (0.013 s) before the peak resultant front tibial acceleration that occurred within 300 frames (1.25 s) prior to the overall (for the trial) peak resultant forearm acceleration. this was based on lamb et al’s[15] finding that peak resultant acceleration at the front tibia occurred on average 0.013 ± 0.006 s after front foot contact in cricket fast bowlers. back foot contact was identified as occurring four frames (0.017 s) before the peak resultant back tibial acceleration that occurred within 100 frames (0.42 s) prior to front foot contact. this was based on lamb et al’s[15] finding that peak resultant acceleration at the back tibia occurred on average 0.016 ± 0.009 s after back foot contact in cricket fast bowlers. ball release was identified as occurring at the instant of the peak resultant bowling forearm acceleration that was recorded within 50 frames (0.21 s) after front foot contact. this was based on spratford et al’s[16] use of peak outward wrist acceleration to successfully identify ball release within 0.014 s limits of agreement. the follow-through ground contact was identified as occurring five frames (0.021 s) before the peak resultant back tibial acceleration that occurred within 125 frames (0.52 s) after ball release. this was based on lamb et al’s[15] finding that peak resultant acceleration at the back tibia occurred on average 0.019 ± 0.011 s after the follow-through ground contact in cricket fast bowlers. the back foot contact phase was defined as beginning at back foot contact and ending at front foot contact. the front foot contact phase was defined as beginning at front foot contact and ending at ball release. the follow-through phase was defined as beginning at ball release and ending at the follow-through ground contact. the total movement was defined as the sum of these three phases. for each bowler, the average duration of each of the three phases was determined as a percentage of the total movement. a weighted average of the entire sample, with leftand righthanded bowler groups weighted at 50% each, calculated the average durations to be 32% for back foot contact, 22% for front foot contact, and 46% for follow-through. all joint and segment angle data for each trial were time-normalised to 101 data points (0%-100% of the movement) via piecewise linear length normalisation.[17] the back foot contact phase was normalised to 0%-32%, front foot contact 32%-54%, and follow-through from 54%-100% of the movement. all trials per player were ensemble averaged to produce a single time-normalised curve per player (i.e. six left-handed average curves and 20 righthanded average curves) for each front knee flexion-extension angle, back knee flexion-extension angle, front hip flexionextension angle, back hip flexion-extension angle, pelvis transverse plane rotation, trunk transverse plane rotation, and trunk side flexion. all frontal and transverse plane angles for left-handed bowlers were adjusted (multiplied by -1) so that the anatomical definitions aligned to those used for right-handed bowlers could be directly compared. original research 3 sajsm vol. 35 no.1 2023 statistical analysis the distribution of phase and movement duration data was assessed via the shapiro-wilks’ test, with left-handers’ total movement (w = 0.725, p = 0.011) and back foot contact (w = 0.694, p = 0.005) durations, but no other durations (0.915 ≤ w ≤ 0.986, 0.065 < p < 0.985) deviating significantly from normality. equality of variance was assessed via levene’s test, with front foot contact (f(1) = 4.357, p = 0.048) but no other durations (0.926 ≤ f(1) ≤ 1.719, 0.202 ≤ p ≤ 0.345) deviating significantly from equal variance. absolute durations (in seconds) were compared between leftand right-handed bowler groups via independent samples t-tests (parametric, for follow-through) or the mann-whitney test (nonparametric, for other durations) within jasp (v 0.16.2.0, amsterdam, netherlands). data were reported as median (interquartile range) for all durations to enable direct comparisons. estimates of effect size (es, cohen's d for t-test and rank biserial correlation for the mannwhitney test) and their 95% confidence intervals were reported. effect sizes were interpreted as 0.1 ≤ small < 0.3, 0.3 ≤ medium < 0.5, and large ≥ 0.5.[18] all timenormalised joint and segment angle onedimensional waveforms were compared between leftand right-handed bowler groups via statistical parametric mapping independent samples t-tests using open source (https://www.spm1d.org) matlab (v 2022b, mathworks, natick, ma) script. for each continuous onedimensional test, the critical test statistic and supra-threshold cluster were reported where the test statistic field exceeded the critical threshold. alpha was set a priori at 0.05 for all discrete and continuous tests, with no control for multiple comparisons made due to the exploratory and hypothesisgenerating nature of the study. results participant characteristics twenty-six injury free fast bowlers (6 left-handed, 20 righthanded) with a mean age of 15.4 ± 0.9 years participated in this fig. 1. angle of release for a left or right-handed bowler bowling ‘around’ or ‘over’ the wicket. (a) lefthanded bowler bowing around the wicket to a left-handed batter; (b) left-handed bowler over the wicket to left-handed batter; (c) right-handed bowler bowling around the wicket to a right-handed batter; (d) righthanded bowler bowling over the wicket to a right-handed batter; (e) left-handed bowler bowling around the wicket to a right-handed batter; (f) left-handed bowler bowling over the wicket to a right-handed batter; (g) right-handed bowler bowling around the wicket to a left-handed batter; (h) right-handed bowler bowling over the wicket to a left-handed batter. original research sajsm vol. 35 no.1 2023 4 study. participants had a body height of 178.8 ± 5.2 cm, body mass 71.6 ± 8.1 kg, and body mass index of 22.4 ± 2.4 kg/m2. movement durations left-handed bowlers had significantly shorter absolute back foot contact durations (in seconds) than their right-handed counterparts (es = 0.58 [95% ci: 0.13 – 0.84]; p = 0.036). durations of other phases and the total movement were not significantly different between the groups (0.273 ≤ p ≤ 0.725; table 1; figure 2). bowling kinematics there were no significant differences between leftand righthanded bowlers in any measured sagittal plane (flexion/extension) angles at any time in the movement (figure 3). in the transverse plane (figure 4), although there were again no significant differences (p > 0.05), peak differences in mean pelvis (3.3°; left > right) and trunk (6.8°; left > right) rotation occurred close to ball release timing (56% of the movement, with ball release at 54%). in the frontal plane (figure 5), left-handed players had significantly more trunk side flexion (p = 0.037, peak difference 9.8°) during the final part of the front foot contact phase and slightly after ball release (from 49 – 56% of the movement) compared to right-handed bowlers. discussion the current study sought to determine whether there are kinematic differences between leftand right-handed fast bowlers and to consequently contribute to the limited research on left-handed bowlers. the main findings when comparing leftand right-handed bowlers in this study were that lefthanded bowlers spent less time at back foot contact and utilised more trunk-side flexion. they also had qualitatively, but not significantly, greater pelvis and trunk longitudinal rotations. the left-handed bowlers utilised more trunk side flexion than the right-handed bowlers. unfortunately, increased trunk side flexion has also been linked to a higher risk of sustaining a lower back injury.[19, 20] the posterior muscles within the table 1. median (interquartile range) durations of total movement and individual phases for leftand right-handed cricket fast bowlers movement phase left-handed (s) right-handed (s) p-value effect size 95% confidence interval back foot contact 0.153 (0.148 – 0.158) 0.177 (0.170 – 0.223) 0.036 0.58 0.13 0.84 front foot contact 0.115 (0.113 – 0.122) 0.112 (0.098 – 0.132) 0.523 0.18 -0.33 0.62 follow-through 0.245 (0.225 – 0.272) 0.262 (0.213 – 0.286) 0.725 0.17 -0.751.08 total 0.512 (0.498 – 0.531) 0.560 (0.511 – 0.585) 0.273 0.31 -0.22 0.69 statistical tests correspond to independent samples t-test (cohen's d effect size) for follow-through and the mann-whitney test (rank biserial correlation effect size) for other durations. fig. 2. distribution and individual data points for back foot contact phase (top left), front foot contact phase (top right), followthrough phase (bottom left), and total movement (bottom right) durations by leftand right-handed cricket fast bowlers. horizontal lines on the box and whisker plots represent median and interquartile range. original research 5 sajsm vol. 35 no.1 2023 fig. 3. sagittal plane joint angles: front knee flexion/extension (top left); back knee flexion/extension (top right); front hip flexion/extension (bottom left); and back hip flexion/extension (bottom right). mean (solid lines) ± standard deviation (shaded areas) (left of each sub-figure) and statistical parametric mapping independent samples t-test result (right of each sub-figure) comparing leftand right-handed cricket fast bowlers from 0%-100% of the total time-normalised movement (back foot contact phase + front foot contact phase + follow-through phase, with individual phases separated by dashed vertical lines at front foot contact (left) and ball release (right)). the right-hand aspect of each sub-figure indicates statistical significance if the black tstatistic crosses the red dashed critical threshold. fig. 4. transverse plane segment angles: pelvis rotation (left) and trunk rotation (right). mean (solid lines) ± standard deviation (shaded areas) (left of each sub-figure) and statistical parametric mapping independent samples t-test result (right of each subfigure) comparing leftand right-handed cricket fast bowlers from 0%-100% of the total time-normalised movement (back foot contact phase + front foot contact phase + follow-through phase, with individual phases separated by dashed vertical lines at front foot contact (left) and ball release (right). the right-hand aspect of each sub-figure indicates statistical significance if the black tstatistic crosses the red dashed critical threshold. original research sajsm vol. 35 no.1 2023 6 lumbopelvic region play a prominent role in stabilising the spine during the bowling action, specifically when compressive and shear forces are high.[21] protective morphological abdominal wall muscle adaptations have also been described in studies investigating risk factors related to lower back injuries among pace bowlers.[22, 23] implementation of strategies aimed at activating posterior lumbopelvic and abdominal wall muscles to ultimately offset forces related to increased trunk side flexion might therefore be especially relevant to left-handed bowlers. however, future research is needed to confirm this hypothesis. determining the relationship between hand dominance and lower back injury risk is beyond the scope of our study in that our inclusion criteria required bowlers to be injury free and the cross-sectional descriptive study design did not allow for causality to be established. the increase in trunk side flexion and possible but unclear increases in trunk rotations may have been facilitated by an earlier grounding of the front foot, resulting in shorter back foot contact phases in left-handed bowlers within this study. while it appeared that one left-handed player had longer movement phase durations compared to other lefthanded players (figure 2), it is important to note that this was not consistent across all phases and not necessarily the same player. due to this study’s exploratory nature, a relatively small sample size was employed and although it seems as if the parameters were mechanically related to one another, this is a hypothesis worthy of exploration in future studies. human movement is complex, and it is important to consider the integration of the various movement components throughout the entire movement. this study required left-handed bowlers to bowl over the wicket to a left-handed batter; however, this is not a common occurrence in cricket. left-handed bowlers may have adapted their bowling technique because of frequently bowling to right-handed batters. the majority of batters use a righthanded batting technique. brooks et al[24] found that only 24% of batters in the 2003 cricket world cup were left-handed. furthermore, considering that only 8% of fast bowlers are lefthanded[25] the chances are very slim that a left-handed fast bowler will bowl to a left-handed batter. when a left-handed bowler bowls to a left-handed batter, these movement components which developed when bowling to a righthanded batter, may have remained ingrained in their bowling actions. the unique kinematic strategies displayed by left-handed bowlers when compared to right-handed bowlers seemed to be motivated by a deliberate in-game strategic approach. a right-handed bowler bowling over the wicket to a righthanded batter and aiming for the ball to hit the top of the off stump (as shown in figure 1d), will bowl in a fairly straight line. however, when a left-handed bowler bowls over the wicket to a right-handed batter (figure 1f), in aiming for the top of the off stump, and to avoid the danger area on the pitch, the left-handed bowler needs to bowl at an angle. it is therefore likely that the left-handed bowlers employed more trunk side flexion and possibly rotation to achieve their goal. all bowlers were given an equivalent bowling task in that they bowled ‘over the wicket’ towards a batter of the same handedness as they are (figures 1b and d). the leftand righthanded bowlers therefore performed a bowling task as a mirror image of one another. when tasked with bowling from the left of the wicket to a right-handed batter, left-handed bowlers will necessarily be releasing the ball from a relatively wider release position (‘around the wicket’ as shown in figure 1e) compared to their right-handed counterparts performing the same task (‘over the wicket’ as shown in figure 1h). bowling ‘around the wicket’ compared to ‘over the wicket’ may lead to differences in bowling kinematics. the instructions given to bowlers in terms of the above should be taken into consideration in the methods of future studies. although the approach taken in our study ensured comparability of bowling technique, it was also an unnatural situation for a left-handed bowler to bowl to a lefthanded batter seeing that there are very few left-handed batters. a limitation of this study is that an aspect of temporal uncertainty will have been introduced by the estimation of ground contact and ball release events informed by peak resultant accelerations and literature values. the literature values used to inform these estimations reported ground contact standard deviations of 0.006-0.011 s[15] and ball release limits of agreement of 0.014 s.[16] this limitation relates to the commonly encountered trade-off between fieldand fig. 5. frontal plane trunk side flexion angle. mean (solid line) ± standard deviation (shaded area) (left) and statistical parametric mapping independent samples t-test result (right) comparing leftand right-handed cricket fast bowlers from 0%-100% of the total time-normalised movement (back foot contact phase + front foot contact phase + follow-through phase, with individual phases separated by dashed vertical lines at front foot contact (left) and ball release (right)). the right-hand graph indicates statistical significance if the black t-statistic crosses the red dashed critical threshold. original research 7 sajsm vol. 35 no.1 2023 laboratory-based data collection methodologies. considering the exploratory, descriptive nature of this cross-sectional study, no practical recommendations can be made to coaches, players and clinicians at this stage. the findings from this study will inform future research investigating the potential to augment or counter the potential ‘unorthodox’ nature of the left-handed cricket bowling action. for example, knowledge of the increased trunk side-flexion in left-handed bowlers may inform research into coaching interventions specific to variations in the bowling task. in addition, future studies exploring the role of handedness in injury risk given the known links between trunk kinematics and lumbar injuries in cricket fast bowlers will add further value in terms of clinical implications. conclusion leftand right-handed bowlers displayed similar sagittal plane kinematics when performing an equivalent bowling task. however, they appeared to use non-sagittal plane movements differently around the time of ball release. primarily, left-handed bowlers utilised more trunk side flexion. they also had shorter back foot contact durations on average compared to right-handed players. the kinematic differences identified in this study can inform future research investigating the effect of hand dominance on bowling performance and injury risk. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors would like to acknowledge each participant for taking part in this study. author contributions: bo: conceptualisation, design, methodology, interpretation of data, writing. nb: formal analysis, writing. jj: interpretation of data, writing. lo: interpretation of data, writing. cm: interpretation of data, writing. jl: methodology, interpretation of data. sm: formal analysis and interpretation of data, writing. all authors edited, reviewed and approved the final version to be published. references 1. kiely n, pickering rodriguez l, watsford m, reddin t, hardy s, duffield r. the influence of technique and physical capacity on ball release speed in cricket fast-bowling. j sports sci 2021;39(20):2361-2369. [doi: 10.1080/02640414.2021.1933349] [pmid:34096462] 2. felton pj, yeadon mr, king ma. optimising the front foot contact phase of the cricket fast bowling action. j sports sci 2020;38(18):2054-2062. [https://doi.org/10.1080/02640414.2020. 1770407] [pmid:32475221] 3. worthington pj, king ma, ranson ca. relationships between fast bowling technique and ball release speed in cricket. j appl biomech 2013;29(1):78-84. [doi: 10.1123/jab.29.1.78] [pmid:22813926] 4. senington b, lee ry, williams jm. biomechanical risk factors of lower back pain in cricket fast bowlers using inertial measurement units: a prospective and retrospective investigation. bmj open sport exerc med 2020;6(1):e000818. [doi: 10.1136/bmjsem-2020-000818] [pmid:32843992] 5. senington b, lee ry, williams jm. the use of inertial measurement units to identify biomechanical factors of performance in cricket fast bowlers. isbs proceedings archive 2022;40(1):632 6. solomito mj, ferreira jv, nissen cw. biomechanical differences between leftand right-handed baseball pitchers. sports biomech 2017;16(2):143-151. [doi: 10.1080/14763141.2016.1186725] [pmid:27256719] 7. loffing f, hagemann n, strauss b. left-handedness in professional and amateur tennis. plos one 2012;7(11):e49325. [https://doi.org/10.1371/journal.pone.0049325] [pmid:23145151] 8. hagemann n. the advantage of being left-handed in interactive sports. atten percept psychophys 2009;71(7):1641-1648. [https://doi.org/10.3758/app.71.7.1641] [pmid:19801623] 9. grouios g, tsorbatzoudis h, alexandris k, barkoukis v. do lefthanded competitors have an innate superiority in sports? percept mot skills 2000;90(4):1273-1282. 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[https://commons.nmu.edu/isbs/vol36/iss1/66/] 15. lamb mo, mcerlain-naylor sa, felton pj, brooke-wavell k, king ma. surface measured accelerations during cricket fastbowling. 40th isbs proceedings archive 2022;40(1):86 16. spratford w, portus m, wixted a, leadbetter r, james da. peak outward acceleration and ball release in cricket. j sports sci 2015;33(7):754-760. [doi: 10.1080/02640414.2014.962577] [pmid:25412692] 17. helwig ne, hong s, hsiao-wecksler et, polk jd. methods to temporally align gait cycle data. j biomech 2011;44(3):561566. [doi: 10.1016/j.jbiomech.2010.09.015] [pmid:20887992] 18. pautz n, olivier b, steyn f. the use of nonparametric effect sizes in single study musculoskeletal physiotherapy research: a practical primer. phys ther sport 2018;33:117-124. [doi: 10.1016/j.ptsp.2018.07.009] [pmid:30077090] 19. bayne h, elliott b, campbell a, alderson j. lumbar load in adolescent fast bowlers: a prospective injury study. j sci med sport 2016;19(2):117-122. 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[doi: 10.1080/713754208] [pmid: 15513028] https://doi.org/10.1080/17461391.2015.1135985 https://doi.org/10.1016/j.ptsp.2017.08.078 https://doi.org/10.1016/j.jsams.2015.04.009 https://doi.org/10.1080/713754208 original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license sport during the covid-19 bio-bubble: wellness and opinions in south african elite football k bahdur,1 d phil, msc; l pillay,2,3 mbchb, msc (med); d dell’oca,4 ba (hons) 1 human movement science, faculty of health science, nelson mandela university, gqeberha, south africa 2 wits institute of sports health, department of health sciences, university of witwatersrand, johannesburg, south africa 3 section sports medicine, university of pretoria, pretoria, south africa 4 supersport international, blairgowrie, randburg, south africa corresponding author: k bahdur (khatija@mandela.ac.za) the covid-19 pandemic imposed unique and unfamiliar stress on different population groups, including sporting codes.[1,2] sports bodies were forced to end the 2019/2020 season without declaring champions (for example, in the netherlands), or with declaring the top team in the league as champions despite not all matches being played (as in scotland), or to identify methods to complete their seasons.[3] most sports opted to complete their 2019/2020 season under restricted conditions, which varied from frequent testing to complete bio-bubbles (i.e. an environment sealed off from the outside world and accessed by a limited number of people only, used to allow events such as sports matches to take place during the coronavirus). the south african premier soccer league (psl) opted for a biologically safe environment (bse)[4] with all teams and other persons entering the bse required to be tested for covid-19 using polymerase chain reaction (pcr) nasal swabs prior to entry to the bse no contact was made with those outside the bse and all matches were played in a single province. this meant that all teams, match officials, transport services, media and hotel staff were required to stay in hotels and were faced with other restrictions, including limited contact with teammates and other persons outside of training and matches. strict schedules dictated movements within the hotels and the bse environment.[5] all persons within the bse were subjected to daily symptom and temperature screening at various points in order to ’red flag’ suspicious cases and to investigate these accordingly. in addition to exposure to pandemic-related stressors, the bse also increased the risk of magnification of other stressors, e.g. compacted competition loads and limited recovery. research has identified different factors as contributors to mental fatigue and depression in football. these included the inability to rest from the sport, lack of job security[6], feeling isolated, lack of time with family and friends, pressure for results, and compacted competition schedules.[7] in addition, long camps and the only interaction within the teams’ football circles can be psychologically stressful, and increased the risk of isolation and decreased motivation. recent studies of south african athletes during lockdown (alert level 5) have shown the physical and mental effects athletes described.[2] such conditions are likely to induce both mental and physical fatigue and could result in players being at an increased risk of injury.[8] the covid-19 pandemic has increased symptoms of depression and anxiety, including sleep and mood disturbances, in footballers.[9] bse restrictions ran the risk of amplifying these factors as players faced isolation, even from teammates. also, the financial impact of covid-19 on clubs was unpredictable, resulting in a greater fear of loss of jobs and pay cuts. on the field, pressure to complete the 2019/2020 season with enough time to begin the 2020/2021 season meant matches every two-three days, requiring all personnel to be able to rest from one match and focus on the next, while correcting and adapting strategies and weaknesses from the previous match, in preparation for the next match. this added greater physical and mental strain for all stakeholders. normally, players will develop strategies to cope with these challenges. regular contact with family and social support structures are influential. the bse restricted such contact with people outside this environment to video, text or make online communication with hotel-limited bandwidth, and personal circumstances leading to data limitation. usually, over time, players also develop basic preand post-match strategies that get them into the right disposition, physically and mentally, for competition. this can include going out with family and/or friends to decompress after a match, or socialising around the hotel pool with specific teammates on game day. the strict guidelines around matches in the covid-19 bio-bubble meant adjustments had to be made to routines. spectators also can play a role in motivating teams. playing behind closed doors (spectatorless) became the norm for all matches. in training, background: covid-19 imposed challenges on professional sport, with restrictions leading to the delay in the completion of the south african premier soccer league (psl). creating a biologically safe environment (bse) provided a solution enabling the 2019/2020 season to be completed. objectives: evaluating the impact that the bse had on player wellness and what coping mechanisms were used in the bse. methods: a questionnaire was distributed to psl teams on the final weekend in the bse. it consisted of three validated psychology questionnaires. an additional section focused on the impact and coping strategies during the psl’s bse. results: a total of 37 completed questionnaires were analysed. general anxiety (4.7±4.2) and depression levels (4.8±3.9) were at an overall low. the health of the players, as well as separation from and concerns about family, were the greatest contributors to anxiety. electronic communication with family and friends, social interactions with others in the bse and time spent on self-reflection were important coping mechanisms for players. as time progressed, they adapted to the bse. conclusion: the bse did not have a negative impact on the anxiety and depression levels of the respondents, with a variety of coping mechanisms key helping them adapt in the bse. keywords: isolation, sport, biologically safe environment, coping mechanisms, mental toughness s afr j sports med 2022;34:1-7. doi: 10.17159/2078-516x/2022/v34i1a12528 mailto:khatija@mandela.ac.za http://dx.doi.org/10.17159/2078-516x/2022/v34i1a12528 https://orcid.org/0000-0002-8353-3376 https://orcid.org/0000-0003-2940-6541 original research sajsm vol. 34 no.1 2022 2 players are exposed to competition-like situations. coaches plan for a gradual adaptation to new scenarios. the lack of preparation time between matches meant that for many teams competition was coupled with the need to adjust to the ‘new normal’ (i.e. spectatorless and limited physical interactions) and the development of new preand post-match habits.[9] the build-up to the resumption of the league also contributes greatly to the emotional and psychological strain.[9] in the bse, personnel were exposed to an environment which may have added to their psychological load. the lack of evidence-based solutions and prior experience with similar circumstances magnified the challenges experienced. this study examined how living in the bse impacted on the psychological measures related to anxiety and depression and identified certain strategies that personnel used to cope. methods participants a total of 37 completed questionnaires were analysed. respondents were from different clubs in the psl and to ensure anonymity no identifying characteristics, such as club or age, were recorded. they included analysts (n=2), coaches (n=6), managers (n=4), medical personnel (n=2) and players (n=23). four players who did not answer the questionnaire from one club were interviewed about their experience in the bse six months after the bse. the interviews followed a semistructured format and were conducted telephonically or virtually. all respondents were male. ethical approval and data collection the research ethics committee from the nelson mandela university applied and was granted ethics approval (ethics number: h20-hea-hms-006). the questionnaire and information sheet were circulated through contacts within the football fraternity in the bse. data collection utilising the questionnaire took place during the final weekend of the bse and interviews were conducted six months after the bse. instrument an online questionnaire was developed using a web-based survey tool (https://www.surveymonkey.com) to allow an investigation into the health and anxiety profiles, and coping strategies used during the psl’s bse. the questionnaire consisted of three standardised psychology questionnaires, and an additional section focused on the impact and coping strategies in the bse. these were adapted from validated questionnaires, as none existed at the time specific to these scenarios. the questionnaire was organised into four sections: section a: general anxiety disorder-7 (gad-7); section b: patient health questionnaire-9 (phq-9) section c: mental toughness inventory -7 (mti-7) section d: causes of anxiety, impact of the psl’s bse and coping mechanisms the gad-7 and phq-9 were coded as minimal (0–4), mild (5– 9), moderate (10–14) and severe (≥15).[1] interview questions included: • what was it like playing out the season in the bse? • how did it differ from a usual season? • what did you do to pass the time? • how did it affect the team? • who provided the greatest relief during the bse? • how did the team help players cope individually and as a unit? • how did the break compare to lengthy injury lay-offs? • how difficult was it to adjust to the bio-bubble? • how well do you feel the covid protocols were implemented? • how did you find not having a roommate impacted you? • do you believe the bse advantaged any teams or players? fig. 1. subjectively identified causes of anxiety for respondents (n=37) using an adapted questionnaire. a negative value indicates no anxiety experienced; a positive value indicates that anxiety was experienced. https://www.survey/ original research 3 sajsm vol. 34 no.1 2022 • did you as players feel team morale was severely impacted by not having fans at the venue? statistical analysis data were analysed quantitatively and qualitatively as deemed appropriate. descriptive statistics were tabulated for the categorical and multiple response questions. the pearson correlation coefficient was used to identify any relationships between mental toughness, general anxiety and the participant’s health. the one-way anova was used to identify any significant differences between the gad-7, phq9 and mti based on the identified causes of anxiety and coping strategies utilised. statistical significance was placed at p<0.05. results the results are divided into five sections. the first section addresses general anxiety and participant health. the second section focuses on the impact of the bse and coping strategies used. the third section describes the mental toughness profiles. the fourth section explores relationships between section 3 and section 1 and 2. the concluding section summarises the information obtained from the interviews. section 1: anxiety and participant health gad-7 results showed low anxiety levels with a mean of 4.7±4.2. only one respondent had anxiety levels classified as extreme and two others were in the moderate classification. phq-9 results were similar with a mean of 4.8±3.9 and none of the results fell into the severe depressive category. fig. 1 highlights some of the factors contributing to anxiety. section 2: impact of the bse adapting to the bse varied according to different participants. fig. 2 illustrates the breakdown of the difficulty respondents felt when adapting to the bse in different contexts. the respondents used different coping mechanisms, which had varying impacts on their ability to adapt to the bse. fig. 3 highlights the extent to which different coping fig. 2. difficulty experienced by respondents (n=37) in adapting to the biologically safe environment (bse) under living, training and playing/competition conditions using an adapted questionnaire. fig. 3. subjectively identified coping mechanisms and the extent of its effect for respondents (n=37) using an adapted questionnaire. full column titles: column 4, “reading articles/blogs/news reports from other sports people or footballers in other countries”; column 5, “interactions with people in football who are not part of the bse”; column 6, “interactions with people in football who are not in my team but subjected to the bse”; column 8, “interactions with the team scientific and medical support structures”. respondents (%) original research sajsm vol. 34 no.1 2022 4 mechanisms were effective. fig. 4 ranks the actions that helped the respondents switch off from football. section 3: mental toughness mental toughness scores within the group were high (47.1±2.1), with only 11% of the respondents scoring less than 20 points in the mti. section 4: relationship between sections 3 and 1 fig. 5 shows the correlations between the results of the phq9, gad-7 and the mti. this has been broken down based on the role of the respondents. table 1 summarises the significant relationships between the phq-9, gad-7 and mti with the causes of anxiety and coping techniques utilised. fig. 4. identified methods to rest from football for respondents (n=37). methods ranked from most to least effective. fig. 5. relationship between general anxiety disorder-7 (gad-7), mental toughness inventory -7 (mti) and patient health questionnaire-9 (phq-9) based on each role played in the team. team consists of analyst (n=2), coach (n=6), manager (n=4), medical personnel (n=2) and players (n=23). axes represent score values for each questionnaire. original research 5 sajsm vol. 34 no.1 2022 section 5: interviews at the six-month interview, the following emerged: three of the players indicated that mental toughness was key in helping them to get through the bse, but one player highlighted that they were just relieved to be able to finish the season and that “the bse was well organised which made the transition easier”. one player highlighted that “it got more difficult at the end”, but believed he “needed to persist”. players had to adapt to spending more time alone than they were used to in camp settings, with the bse not allowing players to share rooms. players saw this as a challenge but found there was greater time for self-reflection and introspection. one player highlighted how he used the time to review his goals, and two players (in addition to the 14 from the questionnaire) spent their time reading. being away from the family was identified as one of the greatest challenges, and players had to rely on technology to stay in touch. discussion there is evidence that elite football causes high levels of mental and physical stresses.[10] the causes extend beyond just competition requirements. the nature of the game and fixtures results in footballers often travelling with limited family time. previous studies have also found that professional sports can lead to feelings of isolation, the inability to rest from the sport, a lack of job security and fears over health and safety, are all stressors.[6] this study identified potential off-field causes of anxiety and coping methods used by football personnel in the psl’s bse. general anxiety, mental toughness and participant health scores were also recorded. the covid-19 pandemic enhanced some of these stressors. prior to the bse, there was an expectation of increased risk of anxiety and other mental health symptoms. therefore, team doctors in the bse were sensitised to this and details were shared regarding remote access to mental health. in the buildup to the nba bio-bubble, the nba highlighted potential mental health risks and encouraged teams to utilise their mental health expert(s).[11] despite the additional stressors, the overall general anxiety and participant health profiles were good. the bse served the purpose of reducing the risk of contracting covid-19. the safety measures and overall organisation put in place could have also contributed to a decrease in anxiety. also, football is a contact sport, and while measures to enforce social distancing away from training and matches and prior to the start kick-off, during the match, contact between players is inevitable once a match begins. access to the bse was allowed following a negative covid-19 pcr test, and physical interactions were limited to personnel within the bse who were all subjected to daily symptom screenings. the covid-19 bio-bubble did prove effective in controlling the spread of the virus, with only one reported case in the bse amongst players and one reported case amongst hotel staff. this was similar to the results found in the nba and wnba. in other countries and sporting codes without strict restrictions, there were several cases of covid-19.[11] players found it challenging to adapt to the conditions. the gad-7 and phq-9 scores in this context did indicate that psychological distress based on general anxiety and depression was lower in this cohort than in the general population[12]. to date, there is limited published research on the effects of bses, similar or other contingencies used in professional sport to continue with competition amidst the pandemic. players have spoken about their expectations and experiences. these did vary with the results of this study. nba players have identified increased depression and anxiety while being in the nba biobubble.[11] concerns regarding job security and financial implications were also a cause for anxiety. during the initial stages of the covid-19 outbreak, there was uncertainty as to whether the 2019/2020 football season would be completed. club owners and economists expressed concerns regarding the predicted negative financial impacts in general and what people within the professional sports arena were facing.[13] the completion of the season did minimise the possibility of loss of income. securing salaries of team members could have reduced anxiety. mental toughness has been linked with the ability to predict the results on performance sports.[14] from a psychological perspective, mental toughness is the psychological edge that enables athletes to cope with sporting demands and maintain a consistent and higher level of performance than other table 1. the significant relationship between gad-7, mti and phq-9 with causes of anxiety and coping mechanisms questionnaire impact, cause of anxiety or coping mechanism p-value gad-7 anxiety: concern over my performance 0.005 anxiety: frequent interactions with the team 0.004 anxiety: cabin-fever 0.000 anxiety: being away from family 0.005 phq-9 anxiety: being away from family 0.018 anxiety: stress over health of family 0.010 anxiety: frequent interactions within the team 0.000 anxiety: missing familiarity of home 0.001 coping: interactions with technical team 0.017 coping: interactions with people from other teams who were in the bio-bubble 0.046 playing 0.012 training 0.024 mti training 0.024 living 0.035 coping: interactions with family and friends 0.011 coping: interactions with scientific and medical team 0.041 anxiety: health and wellbeing of family and friends 0.030 gad-7, general anxiety disorder-7; phq-9, patient health questionnaire-9; mti, mental toughness inventory -7. original research sajsm vol. 34 no.1 2022 6 opponents with determination, confidence and control in high-pressure situations.[14] covid-19 created a challenging and high-pressured environment related to sport. duplication of what is stated above. this study found that players with the highest scores in mental toughness found it easiest to adjust under the bse conditions. swedish national female footballers displayed high levels of mental toughness and low anxiety levels when compared to players competing at lower levels.[15] this study found no significant relationship between mt and gad-7 or phq-9 scores, which was contrary to the findings of bohannan which found weak but significant correlations with phq-9 (r = 0.318; p =0.019) and gad-7 (r = -0.315; p = 0.020)[16]. some of the identified stressors were fixture congestion, having nothing to do all day, time away from family and friends, concerns about safety and the ability to cope with the pandemic.[11] noted was the importance of social interactions in the team setting. the greatest causes of anxiety was the fear for the health and safety of family members and, as previously mentioned, missing family members. the effect of isolation from family could have been worsened by the fact that prior to the bse, respondents would have been under harder lockdown rules with their families. thus, the transition to their absence was even greater.[17] however, people involved in sport at this level are used to going for long periods without physical interaction with families. this is particularly true in cases where clubs are based in different cities or countries.[7] mental health experts suggested maintaining social connections and interactions, including non-football interactions within the team set-up and partaking in leisure activities, such as video games, as possible ways to cope with being in the bio-bubble. this study did find these to be useful tools. the most significant coping strategy was linked to social interactions with family and friends, then social media, and lastly, teammates.[17] while interactions with team members and other personnel in the bse were identified as a coping technique, there was some evidence that spending too much time with them contributed to higher gad-7 scores. other contributors to anxiety included cabin-fever, which was similar to findings in the general population where people were confined within their homes. respondents reported on ways in which they rested from football. staying in touch with family and friends was the most utilised tool, followed by social media, and watching television. the use of social media as a means of resting from football is an unexpected finding, since it can increase a player’s exposure to football-related information directly related to them or their team, or also unrelated football content. constant exposure to social media increased the exposure to covid-19-related news and anxieties related to other social media users. the inability to take a break from football is a contributor to mental fatigue and is therefore vital for the physical and mental recovery of players.[6] the psl’s bse differed from the nba where an entire resort was utilised. as previously mentioned, there was access to entertainment and leisure activities which created opportunities to take a break from the game. close family and friends were also allowed to join the bio-bubble in the latter stages. the length of the psl’s bse was shorter. teams were based at different hotels and allocated different training grounds and stadiums for the duration of the bse. access to other activities was limited according to hotel amenities. self-awareness using self-reflection has a positive association with mental toughness (mt) in tennis players.[18] in this study, there was no relationship between mt and self-reflection as a coping method. however, self-reflection, combined with examining the respondents’ goals, was a significant coping mechanism used in the bse. introspection was also identified as a tool for cricketers facing bse situations. the possible negative emotions linked to extensive time with one’s thoughts was highlighted as a risk factor for negative emotions.[19] the advantages of completing the season and the contribution of the bse that enabled the completion of the season, helped mitigate possible negative effects of being in the bse. limitations the cohort was small – only 37 respondents. there were no precovid-19 profiles, thus it was not possible to see how covid19 impacted on the psychological profiles. the positive gad-7 and phq-9 scores could be related to the timing of the data collection. teams were in the bse for six weeks, and the gad7 and phq-9 were completed at the end of the bse. by this time, players were used to the environment and with the end now close, it could have made them feel better. self-reported tools of assessment can sometimes lead to biased responses with respondents opting to provide the responses they feel are expected of them and likely to make them appear more favourable. this has been identified as a reason for the miscalculation of the occurrence of depression.[20] the use of anonymous surveys, with limited identifying questions, was undertaken to minimise the effect of measured responses in the questionnaire. conclusion despite this being the first exposure to a bse, the report of anxiety was low, with no evidence of a reduced mood within the bse. the utilisation of different coping mechanisms and tools to rest from football, as well as the use of technology to keep in touch with people outside the bse, and the support and interactions with team personnel contributed to making the bse easier to manage. mental toughness and resilience, which are highlighted as important characteristics for success in elite sport, could contribute to the adaptations to the changing circumstances. conflict of interest and source of funding: dr pillay was the psl’s covid-19 chief medical officer during the bse. the authors declare no source of funding. acknowledgements: the authors would like to acknowledge the contribution of yale jameson and of all team personnel who distributed the questionnaire. original research 7 sajsm vol. 34 no.1 2022 author contributions: kb was involved in the conceptualisation, data collection, initial write up, data analysis and implementation of the methodology. dd was involved in the initial write up and data collection. lp was involved in contributing to the write up and reviews. references 1. fullana ma, hidalgo-mazzei d, vieta e, et al. coping behaviors associated with decreased anxiety and depressive symptoms during the covid-19 pandemic and lockdown. j affect disord 2020;275: 80–81. [doi: 10.1016/j.jad.2020.06.027] [pmid: 32658829] 2. pillay l, janse van rensburg dc, janse van rensburg a, et al. nowhere to hide: the significant impact of coronavirus disease 2019 (covid-19) measures on elite and semi-elite south african athletes. j sci med sport 2020;23(7): 670–679. [doi 10.1016/j.jsams.2020.05.016] [pmid: 32448749] 3. parnell d, widdop p, bond a, et al. covid-19, networks and sport. manag sport leis 2020; 1–7. [doi: 10.1080/23750472.2020.1750100] 4. ramagole da, janse van rensburg dc, pillay l, et al. implications of covid-19 for resumption of sport in south africa: a south african sports medicine association (sasma) position statement. sa j sports med 2020;32(1):1–5. [doi: 10.17159/2078-516x/2020/v32i1a8986]5. 5. basson ab. life inside the psl bio-secure bubble. new frame, 28 aug 2020; s.l.. https://www.newframe.com/life-inside-thepsl-bio-secure-bubble/ (accessed 4 april 2021). 6. russell s, jenkins d, rynne s, et al. what is mental fatigue in elite sport? perceptions from athletes and staff. eur j sport sci 2019;19(10):1367–1376. [doi: 10.1080/17461391.2019.1618397] [pmid: 31081474] 7. bahdur k, pruna r. the impact of homesickness on elite footballers. j nov physiother 2017; 07: 331. [doi: 10.4172/21657025.1000331] 8. smith mr, thompson c, marcora sm, et al. mental fatigue and soccer: current knowledge and future directions. sports med 2018;48(7):1525–1532. [doi: 10.1007/s40279-018-0908-2] [pmid: 29623604] 9. gouttebarge v, ahmad i, mountjoy m, et al. anxiety and depressive symptoms during the covid-19 emergency period. clin j sport med 2020. [doi: 10.1097/jsm.0000000000000886] [pmid: 32941374] 10. russell s, jenkins d, smith m, et al. the application of mental fatigue research to elite team sport performance: new perspectives. j sci med sport 2019;22(6):723–728. [doi: 10.1016/j.jsams.2018.12.008.] [pmid: 30606625] 11. bird sp. impact of covid-19 on athlete mental health – strategies to promote emotional wellness. int j strength cond 2021;1(1): e1– 5. [doi: 10.47206/ijsc.v1i1.33] 12. gao j, zheng p, jia y, et al. mental health problems and social media exposure during covid-19 outbreak. plos one 2020; 15(4):e0231924. [doi: 10.1371/journal.pone.0231924] [pmid: 32298385] 13. clevenger sm, rick o, bustad j. critiquing anthropocentric media coverage of the covid-19 sport ‘hiatus’. int j sport commun 2020;13(3):559–565. [doi: 10.1123/ijsc.2020-0239] 14. yankov gp, davenport n, sherman ra. locating mental toughness in factor models of personality. pers individ dif 2019; 151: article 109532. [doi: 10.1016/j.paid.2019.109532] 15. kristjánsdóttir h, jóhannsdóttir kr, pic m, et al. psychological characteristics in women football players: skills, mental toughness, and anxiety. scand j psychol 2019;60(6):609–615. [doi: 10.1111/sjop.12571] [pmid: 31489980] 16. bohannan cj. mental toughness as a predictor for pre-season depression and anxiety symptoms, and changes over the course of an athletic season. 2019;76pp: electronic theses and dissertations, 1890. https://digitalcommons.georgiasouthern.edu/etd/1890 (accessed 14 june 2021) 17. ward-henninger c. along with covid-19 and injuries, mental health risks for nba players in disney bubble must also be addressed: cbssport, 2020 https://www.cbssports.com/nba/news/along-with-covid-19-andinjuries-mental-health-risks-for-nba-players-in-disney-bubblemust-also-be/ (accessed 5 february 2021) 18. cowden rg. on the mental toughness of self-aware athletes: evidence from competitive tennis players. s afr j sci 2017;113. [doi: 10.17159/sajs.2017/20160112] 19. bansal n, sheriff s. impact of bio-bubble on the mental health of elite cricketers during the covid-19 pandemic: the bio-bubble fatigue. international journal of sport, exercise and health research 2021;5(2):40-41. [doi: doi.org/10.31254/sportmed.5202] 20. wolanin a, gross m, hong e. depression in athletes: prevalence and risk factors. curr sports med rep 2015;14(1):56–60. [doi: 10.1249/jsr.0000000000000123] [pmid: 25574886] introduction an ultramarathon is an endurance running event that can vary in duration from 50 km during a single day to in excess of 200 km over several days. the physiological and immunological consequences of ultramarathon running have been fairly well documented, highlighting the demanding nature of this type of event.1-4 the physiological demands associated with ultramarathon running potentially have psychological consequences yet there is relatively little coverage of this in the literature. of the studies which have been published, most have focused on personality,5 perceived exertion6 and coping7 but none have specifically explored the relationship between mood and ultramarathon performance. several studies have reported positive effects of running on mood including reduced feelings of depression and confusion.8-10 even though neutral or negative emotional responses to running original research article perceived exertion influences pacing among ultramarathon runners but post-race mood change is associated with performance expectancy abstract objectives. this study investigated whether post-race mood changes among ultramarathon runners are associated with perceived exertion or the discrepancy between their actual and predicted performance times. methods. eight runners completed the puffer ultramarathon, which is a challenging 73 km mountainous race across table mountain national park in south africa. each runner completed a series of profile of mood state questionnaires (poms) 2 days before the race (baseline), on the morning of the race (pre-race) and immediately after the race (post-race). ratings of perceived exertion (rpe) were measured at 13 points during the race using the borg 6-20 scale. the accuracy of performance expectations was measured as the difference between runners’ actual and predicted race times. results. average completion time was 11:31:36±00:26:32 (hh: mm:ss), average running speed was 6.4±2.2 km.hr-1 and average rpe was 14.1±2.0. increased poms confusion was found before the race (33.30.7 v. 37.1±5.2, p=0.014; baseline v. pre-race). post-race increases in poms total mood disturbance (tmd) were correspondence: dr dominic micklewright centre for sports and exercise science department of biological sciences university of essex wivenhoe park colchester essex uk, co4 3sq e-mail: dpmick@essex.ac.uk dominic micklewright (phd) eleni papadopoulou (bsc) david parry (msc) university of essex, united kingdom tamara hew-butler (phd) nicholas tam (bsc) timothy noakes (dsc) university of cape town, south africa sajsm vol 21 no. 4 2009 167 found (168.3±20 v. 137.5±6.3, p=0.001; post race v. baseline) characterised by decreased vigour (43.3±4.0 v. 33.5±7.0, p=0.008; baseline v. post race), increased confusion (33.3±0.7 v. 38.5±4.8, p=0.006; baseline v. post race) and increased fatigue (37.8±4.8 v. 53.8±7.3, p=0.0003; baseline v. post race). a linear increase in rpe was found during the race (r=0.737, p=0.002). the magnitude of their post-race mood change (r=-0.704, p=0.026) was not found to be associated with runners’ average rpe but was found to be negatively correlated with accuracy of the performance predictions. a time series analysis indicated that poms tmd would have taken 142±89 min to recover. conclusions. the results show that rpe influences the way ultramarathon runners pace themselves more than performance expectancy but performance expectations have a greater influence on post-race mood. the magnitude of post-race mood change is associated with the extent of discrepancy between runners’ predicted and actual performance. this has implications for designing appropriate goals and pacing strategies for ultraendurance athletes. have been reported in a few studies,11,12 the generally accepted conclusion is that running is good for mental health.13 the positive psychological changes associated with recreational running probably only have a limited amount of relevance to the much more prolonged and demanding nature of ultramarathon running yet, as the lack of ultramarathon literature shows, this is an under-researched area of sport psychology. in one of the few studies available, a complex pattern of mood change among ultramarathon finishers was found to include reduced tension and vigour with increased fatigue, depression and confusion.14 what their results suggest is an association between ultra-endurance running and unpleasant mood state characterised by changes in the high activation states of tension and vigour, as well changes in the low activation states of fatigue, depression and confusion. interestingly, they account for the change in tension as relief from pre-race anxiety, and the changes in vigour, fatigue, depression and confusion as due to the unique sensations associated with running for such a long time. their conclusions are valid but what needs further consideration is perhaps how intra-individual differences in runners’ circumstances, motives, perceptions of the race environment and conscious cognitive processes potentially influence the way endurance running sensations are interpreted by a runner as an antecedent of perceived exertion and affective experience. according to cognitive theories of emotion the relationship between an event and an emotional response is mediated by various forms of conscious information processing. several theories, such as attribution theory15 and appraisal theory,16 can help to explain how an individual’s conscious thoughts can shape their emotional experience associated with ultra-endurance running. a claim often made is that emotions are strongly influenced by an individual’s conscious cognitive appraisal of a preceding situation or occurrence.17 according to this theory, ultramarathon runners with favourable appraisals of their performance should experience positive moods states after a race but runners who appraise their performance as being poor should experience negative mood states. furthermore, the way athletes appraise their performance will perhaps in turn depend upon their underlying subjective motivations and meanings associated with the race, making the relationship between thoughts and feelings a complex one for ultramarathon runners. the aims of this study were to measure changing patterns of mood among runners before and after an ultramarathon, and explore the relationship between the accuracy of performance expectations, perceived exertion and mood state among ultramarathon runners. it was hypothesised that runners who perform an ultramarathon better than or close to their expectations will experience more positive changes than runners whose performance is worse than expected. an additional purpose of this study was to measure the amplitude and time course of any mood disturbances experienced during the post-race recovery period. method participants eight male and 2 female runners were recruited from the puffer ultramarathon entrant list. the puffer ultramarathon is a challenging mountainous 73.4 km trail race that runs between cape point and cape town across table mountain national park in south africa. all of the participants were moderately or well-trained endurance runners who had completed at least one ultramarathon or ironman triathlon as a qualifier during the 6-month period preceding the study. one female runner did not start the race and one male runner did not finish the race, leaving 8 participants in the study. the age and body mass of runners who completed the study were 41.8±7.1 years and 72.0±8.6 kg. body mass was measured within 1 hour of the start of the race using portable scales. a power analysis indicated a sample size of between 8 and 12 participants would be satisfactory to achieve p-values of <0.05 and <0.01 respectively for a one-tailed linear correlation test with an r-value of >0.7 and power of 0.6. all runners provided their written informed consent to participate in the study, which was approved by the university of cape town ethics committee and conducted in accordance with the declaration of helsinki (amended 2008). mood state measurements throughout this study mood state was measured using the mcnair, lorr & droppleman (1971, 1992) shortened ‘right now’ version of the profile of mood states questionnaire (poms).18 the poms short form comprises 30 single-word mood descriptors, each with a 5point likert response scale, from which subscale scores for tension, depression, anger, vigour, fatigue, and confusion could be calculated. the poms short version was used to minimise questionnaire fatigue associated with the high number of poms trials in this study, and the same investigator was used to administer all of the poms questionnaires. to minimise response bias effects, runners were briefed to complete the poms based upon how they felt at the time rather than attempting to memorise their previous responses, and every time a runner completed a poms they were not able to see any previous questionnaire that they had completed. each participant completed a poms 2 days before the race (baseline trial), on the morning of the race (pre-race trial), immediately after the race (post-race trial) and then at 5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 90 and 105 minutes during recovery. in order to counteract the potential response bias associated with repeated post-race poms trials, participants were instructed to answer the poms as honestly as possible by reflecting on how they felt at that precise moment in time rather than attempting to provide answers based on any previous poms responses that they may have remembered giving. performance expectations two days prior to the race participants were asked to provide an estimate of the time they realistically expected to complete the race (performance expectancy). each participant’s official ultramarathon race time was recorded in minutes. the accuracy of each runner’s performance expectations was calculated by subtracting their actual race time from their predicted race time. this calculation produced a negative number for runners who were slower than expected and a positive number for runners who were faster than expected. all of the runners were familiar with the race profile and the predicted weather conditions when they gave their performance expectations. perceived exertion and performance measurements ratings of perceived exertion (rpe) using the 6 20 borg scale19 were taken at 13 discrete checkpoints throughout the race including the finish line. elapsed times between each of the check points were recorded for each participant and then used to calculate their average running speed. statistical analysis in accordance with the instruction manual,18 poms raw scores were converted to normalised student t-scores for each of the six subscales and total mood disturbance scores (tmd) was calculated 168 sajsm vol 21 no. 4 2009 by subtracting the poms vigour score from the sum of tension, anger, depression, fatigue, and confusion scores. changes in mood state associated with the race were evaluated by comparing baseline, pre-race and post-race measures. for the poms subscales this was determined using a manova with post hoc univariate anovas and paired samples t-tests. trial differences in tmd were measured using a repeated-measures one-way anova with post hoc paired sample t-tests. a bonferonni corrected alpha level of .0167 was used to indicate statistical significance with all t-test results. post-exercise changes in tmd were examined using a time series analysis with holt’s linear trend exponential smoothing to predict the length of time needed for tmd to return to baseline levels (tmd recovery). the amplitude of pre-race changes in tmd and poms subscales was calculated by subtracting baseline values from pre-race values. the amplitude of post-race tmd change was calculated by subtracting baseline tmd scores from post-race tmd scores. pearson’s product moment correlation tests were used to test relationships between the accuracy of performance expectations, average rpe score and the amplitude of post-race changes in poms tmd. pearson’s product moment correlation tests were also used to measure relationships between rpe against (i) distance run and (ii) percentage of race time completed. all effect sizes are calculated as partial eta squared (ηp2)or eta squared (η2). results total mood disturbance (tmd) repeated measures one-way anova indicated a difference in tmd scores between the trials, f(2,21)=15.2, p=0.0003, ηp 2=0.69. post hoc paired samples t-tests indicated higher post-race tmd scores (168.3±20) compared with baseline tmd scores (137.5±6.3), t(7) =-5.6, p=0.001, η2=0.82, and compared with pre-race tmd scores (148.6±19.4), t(7)=-3.7, p=0.008, η2=0.66. there was no difference between baseline and pre-race tmd scores. results of the time series analysis indicated a mean recovery time of 142±89 min with a range of 0 265 min. mean tmd changes are presented in fig. 1. profile of mood states subscales a manova indicated a difference in poms subscale scores between the trials, f(12,32)=4.6, p=0.0003, ηp 2=0.63 and subsequent univariate anovas revealed differences for the confusion subscale, f(2,21)=3.5, p=0.05, ηp 2=0.25, the fatigue subscale, f(2,21)=18.5, p=0.00002, ηp 2=0.64, and the vigour subscale, f(2,21)=5.6, p=0.011, ηp 2=0.35. post hoc paired samples t-tests indicated no differences between baseline and pre-race scores for poms fatigue and vigour but an increase in confusion was found (33.3±0.7 v. 37.1±5.2), t(7)=-2.8, p=0.014, η2=0.53. an increase between baseline and post-race scores was found for poms confusion (33.3±0.7 v. 38.5±4.8), t(7)= -3.5, p=0.006, η2=0.64 and poms fatigue (37.8±4.8 v. 53.8±7.3), t(7)=-6.7, p=0.0003, η2=0.87. a decrease between baseline and post-race scores was found for poms vigour (43.3±4.0 v. 33.5±7.0), t(7)=3.2, p=0.008, η2=0.59. mean poms subscale differences are presented in fig. 2. sajsm vol 21 no. 4 2009 169 fig. 1. preand post-race changes in poms total mood disturbance. increases in tmd relative to baseline scores represent a negative change in mood. ns = not significant; ***p<0.005; **** p<0.001. 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 poms trial (min) m ea n p o m s t m d s co re baseline prerace ***ns **** pre-race post-race fig. 2. preand post-race changes in poms confusion (a), fatigue (b) and vigour (c). decreased vigour and increased confusion and fatigue relative to baseline score indicate a negative change in mood. ns = not significant; **p<0.01; ***p<0.005; ****p<0.001; ***** p<0.0001. ultramarathon and mood change 2 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 poms trial (min) m ea n p o m s c on fu si on s co re baseline prerace ** *** ns a pre-race post-race 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 poms trial (min) m ea n p o m s f at ig ue s co re baseline prerace ns ***** **** b pre-race post-race 24 26 28 30 32 34 36 38 40 42 44 46 48 50 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 poms trial (min) m ea n p o m s v ig ou r s co re baseline prerace ns *** ns c pre-race post-race race performance, performance expectation accuracy, rpe and mood change average race completion time was 11:31:36±00:26:32 (hh:mm:ss), average running speed was 6.4±2.2 km.hr-1 and average rpe was 14.1±2.0. the average running speed and rpe for each of the 13 check points is illustrated in fig. 3a. a positive correlation was found between the distance run and rpe, r=0.737, p=0.002 (fig. 3a) and between the percentage of race time completed, r=0.725, p=0.003 (fig. 3b). a negative correlation was found between running speed and rpe, r=-0.687, p=0.005 (fig. 3c). pearson’s product moment correlation test showed that there was no correlation between the accuracy of performance expectations and the amplitude of pre-race tmd change (r=-0.386, p=0.172) or pre-race confusion change (r=-0.477, p=0.116). a negative correlation was found between the accuracy of performance expectations and post-race tmd amplitude, r=-0.704, p=0.026 (fig. 4a) and post-race confusion amplitude, r=-0.661, p=0.037 (fig. 4b). a positive correlation was found between the accuracy of performance expectations and post-race vigour amplitude, r=0.840, p=0.005 (fig. 4c). there were no other correlations between the accuracy of performance expectations, average rpe, other postrace changes in mood state or tmd recovery time. discussion anticipatory pre-race mood change the first important finding of this study was the change in poms that occurred immediately before the race was characterised by increased levels of confusion. this suggests an anticipatory affective state that, in the absence of actual running sensations, was most likely to be a consequence of participants’ conscious thoughts about their pre-race circumstances and the impending start of the race. the large standard deviation observed in confusion, and indeed all other poms scores, reflects the usual inter-individual variation in feelings of mood but what are more important are intra-individual changes in mood compared with baseline measures. the elevated feelings of confusion experienced by runners immediately before the race may have been due to differing cognitive appraisals and interpretations regarding their specific circumstances and readiness leading up to the race. this is consistent with the view that cognitive theories are needed to account for intraand inter-individual differences in affect.20 in addition to increased confusion, it is surprising that participants did not experience increased feelings of tension before the race given the high stakes associated with failure and wasting months of training and preparation. even though confusion was the only poms subscale affected immediately before the race, the results lend some support to the general idea of mood being influenced by conscious cognitive processes.21 more specifically, it seems that an ultramarathon runner’s pre-race mood state is probably strongly influenced by their own cognitive appraisals. the exact nature of these appraisals needs further investigation because in this study they were not specifically measured. anticipatory mood state and ultramarathon performance the increased confusion that was observed before the race did not seem to be associated with the runners’ overall race performance since there was no correlation between changes in either pre-race confusion or tmd and the magnitude of their performance time prediction error. although not measured in our study it may be that if performance is in anyway influenced by anticipatory affective states, such effects only occur at the beginning of an endurance event but gradually diminish as the race progresses and the sensory, perceptual and cognitive experience of the athlete changes. what is important is the extent to which an athlete’s overall endurance event performance is influenced, if at all, by anticipatory changes in mood. since mood is transient in nature20 it seems quite unlikely that pre-race mood states could have any significant effect on lengthy ultramarathon performances. ultramarathon performance, rpe and post-race mood the linear increases in rpe that were observed when expressed relative to both distance covered and the percentage of exercise time completed suggest that, consistent with previous findings,22,23 an anticipatory strategy to prevent premature fatigue was adopted by the runners whereby they modulated running speed according to their 170 sajsm vol 21 no. 4 2009 fig. 3. puffer ultramarathon race profile with altitude plotted on the primary y-axis and rpe plotted on the secondary y-axis (a). relationship of rpe with percentage of race time completed (b) and average running speed (c). y-error bars represent ± 1 sd for rpe measurements; x-error bars represent ± 1 sd for percentage of overall race time completed at each check point. average speed ± 1 sd between checkpoints is provided in 3a. ultramarathon and mood change 3 r=0.737, p=0.002 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 distance (km) a lti tu de (m ) 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 r p e (b or g 620 s ca le ) race profile rpe 4.8 ± 2.8 kph 10. 2± 1.1 kph 7.1 ± 1.8 kph 3.1 ± 0.2 kph 3.5 ± 0.5 kph 4.9 ± 0.6 kph cp1 cp3 cp4 cp6 cp5 cp 12 cp1 1 cp 10 cp9 cp8 cp7 cp 13 9.2 ± 1.6 kph 6.3 ± 0.5 kph 7.4 ± 0.9 kph 6.4 ± 0.8 kph 4.8 ± 1.0 kph 7.4 ± 6.6 kph cp2 10.1 ± 1.1 kph a r=0.725, p=0.003 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 10 20 30 40 50 60 70 80 90 100 percentage of race time completed (%) r p e (b or g 620 ) b r=-0.687, p=0.005 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 0 1 2 3 4 5 6 7 8 9 10 11 12 average running speed (km.hr-1) r p e (b or g 620 ) c feelings of exertion. all but one of the runners in this study performed worse than they predicted yet, despite the extremely mountainous terrain, all managed to complete the race by performing within sustainable rpe limits that appeared to become less conservative towards the end point as completion certainty increased.24 this suggests that, together with the inconsistent changes in average running speed at the various checkpoints, rpe is of greater importance to pacing than pursuing any performance predictions. a large increase in tmd was observed immediately after the event that was characterised by increases in fatigue and confusion, and a reduction in vigour. given the long and difficult nature of the race such outcomes are not particularly surprising except that, similar to pre-event changes in affect, a great deal of intra-individual variance in the magnitude of post-race affect was found that was surprisingly not strongly associated with their rpe. this suggests that the relationship between an individual’s sensory experience during an endurance event and their affective response is complex and probably mediated by other psychological factors such as conscious appraisals about their performance. it is also acknowledged that from the data we collected it is not possible to differentiate between the extent to which race-specific cognitions and non-race related cognitions influenced runners’ post-race mood. what is apparent from the results is that the majority of participants ran slower than their stated performance expectations which, in addition to the physiological ramifications of running longer, potentially accounts for the unpleasant post-race changes in tmd. in fact, one of the most important findings of this study is the moderate negative correlation that was detected between runners’ post-race tmd amplitude and the accuracy of their performance expectations. most of the runners experienced unpleasant post-race mood states, the magnitude of which appears to be at least partly associated with the degree of accuracy in performance expectancy (fig. 3). perhaps the optimistic performance predictions made by the runners in this study was partly due to the fact that a large proportion of the puffer ultramarathon was off-road and incorporated extreme gradients, making the prediction task more difficult, especially for those runners more accustomed to road running. it is likely that, in endurance events, a runner’s mood state at the end of a race is perhaps more a consequence of cognitive processes that develop during the race rather than rpe as they become gradually aware of whether or not they will achieve their expectations. for example, at the beginning of a long race there will still be some degree of uncertainty about the accuracy of their performance expectations but as they progress towards the end this uncertainty will become resolved according to whether predetermined checkpoints are achieved within expected times or, in instances where the athlete receives continual progression feedback, whether expected average speeds are met. consequently, a runner’s performance appraisals are likely to continually change during a race and perhaps it is these cognitive performance appraisals that have an influence on the feelings of mood experienced by runners immediately after completing the race. this is consistent with both attribution14 and appraisal theory16 in that cognition and feeling states are associated with each other. it is acknowledged that in our study no detailed record of performance appraisals were made and clearly this needs to be done in the future. for some runners completing an ultramarathon or simply enjoying the experience might be interpreted as a success but, as in this study, others’ performance appraisals might be based around achieving a specified time. perhaps, runners’ post-race mood states are also a function of appropriate goal setting, a concept that is closely dependent upon realistic performance expectations. one way in which future studies could be improved would be to collect detailed information of this sort from runners prior to their race. this would enable a better understanding of how many factors, such as previous ultramarathon experience, training status and environmental conditions, influence runners’ emotional states during and after a race. given that our study showed most runners performed worse than expected, it would appear that caution is needed when establishing endurance event outcome goals from performance predictions and expectations. post-race mood recovery dynamics the amount of time needed for post-event changes in tmd to recover to baseline levels was found to be on average 2 hr and 22 min but varied a great deal among participants and extended for as long as 4 hr and 25 min. considering the enduring nature of an ultramarathon our findings suggest a comparatively short recovery period for mood but it is emphasised that this does not reflect participants’ readiness sajsm vol 21 no. 4 2009 171 fig. 4. scattergrams showing the relationship between accuracy of runners’ performance expectations and their post-race changes in tmd (a), poms confusion (b) and poms vigour (c). ultramarathon and mood change 4 r=-0.704, p=0.026 -5 0 5 10 15 20 25 30 35 40 45 50 -120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 completion time prediction error (min) p os tra ce c ha ng e in t m d slower than predicted faster than predicted a r=-0.661, p=0.037 0 1 2 3 4 5 6 7 8 9 10 11 12 -120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 completion time prediction error (min) p os tra ce c ha ng e in p o m s c on fu si on slower than predicted faster than predicted b r=0.840, p=0.005 -20 -15 -10 -5 0 5 10 -120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 completion time prediction error (min) p os tra ce c ha ng e in p o m s v ig ou r c slower than predicted faster than predicted to perform running or any other type of physical activity which will depend upon the recovery of a myriad of other psychological and physiological parameters. correlation tests showed that tmd recovery time did not appear to be related to tmd amplitude or the accuracy of performance expectations. in other words, runners who experienced a big change in affect after the race or whose performance was slower than expected did not necessarily have a longer affect recovery time. again, a more detailed investigation is needed to investigate the cognitive mediators that influence the time course of mood recovery after an ultramarathon. conclusions despite the limitations associated with low participant numbers, the findings of this study provide new insight about patterns of rpe and mood change experienced by ultramarathon runners which is a seriously under-researched area with important applied implications. for unknown reasons, endurance runners appear to make optimistic performance predictions which applied sport psychologists ought to be aware of, particularly if they intend to use these predictions as a basis for certain interventions like goal setting. perhaps preperformance psychological interventions could focus on refining the accuracy of ultra-endurance athletes’ predictions given that failing to meet performance expectations appears to exacerbate any unpleasant post-race mood states. making sure that runners train under similar conditions in the lead-up to a race is very important in terms of developing experience and awareness of their true potential which they can drawn upon to manage and pace themselves accordingly on the day. reinforcing race-relevant experience could be achieved through both physical and psychological training. although not directly measured in this study, there is some inference that cognitive performance appraisals occur throughout the race that are perhaps gradually developed and updated through repeated cycles of comparing expectations against current performance, and that it is these appraisals that underpin post-race affective experience. further investigation is warranted to explore in more detail the relationship between explicit cognitive process and mood change among ultramarathon runners. references 1. wu hj, chen kt, shee bw, chang hc, huang yj, yang rs. effects of 24 h ultra-marathon on biochemical and hematological parameters. world j gastroenterol 2004;10(18):2711-2714. 2. millet gy, lepers r, maffiuletti na, babault n, martin v, lattier g. alterations of neuromuscular function after an ultramarathon. j app physiol 2002;92:486-492. 3. strachan af, noakes td, kotzenberg g, nel ae, de beer fc. c reactive protein concentrations during long distance running. br med j (clin res ed) 1984;289(6454):1249-1251. 4. davies ct, thompson mw. physiological responses to prolonged exercise in ultramarathon athletes. j app physiol 1986;61:611-617. 5. folkins c, wieselberg-bell n. personality profile of ultramarathon runners: a little deviance may go a long way. j sport behavior 1981;4(3):119-127. 6. utter ac, kang j, nieman dc, vinci dm, et al. ratings of perceived exertion throughout an ultramarathon during carbohydrate ingestion. perceptual and motor skills 2003;97(1):175-184. 7. rauch tm, tharion wj, strowman sr, shukitt bl. psychological factors associated with performance in the ultramarathon. j sports med physical fitness 1988;28(3):237-246. 8. weinberg r, jackson a, kolodny k. the relationship of massage and exercise to mood enhancement. the sport psychol 1988;2:202-211. 9. dyer jb, grouch jg. effects of running and other activities on moods. percept motor skills 1988;67(1):43-50. 10. markoff ra, ryan p, young t. endorphins and mood changes in long-distance running. med sci sports exercise 1982;14(1):11-15. 11. hassmén p, blomstrand e. mood change and marathon running: a pilot study using a swedish version of the poms test. scand j psychol 1991;32:225-232. 12. yates a, shisslak cm, allender j, crago m, leehey k. comparing obligatory to nonobligatory runners. psychosomatics 1992;33:180-189. 13. galper di, trivedi mh, barlow ce, dunn al, kampert jb. inverse association between physical inactivity and mental health in men and women. med sci sports exercise 2006;38(1):173-178. 14. tharion wj, mcmenemy dj, terry al, rauch tm. recovery of mood changes experienced when running and ultramarathon. perceptual and motor skills 1990;71:1311-1316. 15. weiner b. an attributional theory of motivation and emotion. new york: springer, 1986. 16. lazarus rs. emotion and adaptation. new york: oxford university press, 1991. 17. scherer kr. emotion as a process: function, origin, and regulation. social sci info 1982;21:555-570. 18. mcnair dm, lorr m, droppleman lf. profile of mood state manual (revised). san diego, ca: educational and industrial testing service, 1992. 19. borg g. psychophysical bases of perceived exertion. med sci sports exercise 1982;14:377-381. 20. power m, dalgleish t. cognition and emotion: from order to disorder. hove: psychology press, 1997. 21. riskind jh. the mediating mechanisms in mood and memory: a cognitive priming formulation. in d. kuiken (ed.), mood and memory: theory, research and applications. special issue of j social behav personality 1989;4:39-43. 22. crewe h, tucker r, noakes td. the rate of increase in perceived exertion predicts the duration of exercise to fatigue at a fixed power output in different environmental conditions. eur j appl physiol 2008;103:569577. 23. noakes td, snow rj, febbraio ma. letter to the editor. j appl physiol 2003;96:1571-1573. 24. tucker r, noakes t. the anticipatory regulation of performance: the physiological basis for pacing strategies and the development of a perception-based model for exercise performance. br j sports med 2009;43(6):392-400. 172 sajsm vol 21 no. 4 2009 introduction the global prevalence of chronic, non-communicable diseases (ncd) is on the rise, with developing countries experiencing the greatest burden, and in which cardiovascular disease is already the leading cause of mortality. 1 similarly, the number of persons with diabetes is projected to double between 2000 and 2030, with over 80% or 300 million from developing countries. this increase in the prevalence of chronic diseases in the developing world has been attributed to changes in lifestyle associated with development and urban migration, including obesity, unhealthy diet, smoking and physical inactivity. 2 the urgent need to address these risk factors in both developed and developing countries is reflected in the world health organization global strategy on diet and physical activity for health. 3 importantly, these risk behaviours track from childhood, with body mass index (bmi) levels in childhood strongly predictive of adult obesity. 4 in the bogalusa heart study overweight children (bmi>95th centile) at 2 5 years were found to be 4 times as likely to become overweight adults. 5 south africa is a country of paradox, where obesity in children co-exists with stunting and early nutritional deprivation. for example, in primary school children 22% of girls and 17% of boys are overweight or obese. 6 in children under the age of 9 years, overweight and stunting are equally prevalent, and risk of obesity in stunted children is nearly twofold higher, with potentially long-term negative health consequences. 7 south african children also demonstrate unhealthy eating habits with school tuck-shop choices favouring cooldrinks, chips, cheese curls and fried cakes (70%), and urban primary school learners report eating fruit or vegetables less than 3 times per week. 8 of concern is that many schools rely on income generated from these tuck-shops for supplemental income and informal vendors, who typically sell foods of low nutritional value, high in fats and sugars, are also very common. similarly, recent studies suggest that 40% of children and youth are getting little or no moderate to vigorous activity each week. 9 with only just over half of high school learners reporting regularly scheduled physical education classes, less than 60% of these engage in vigorous activity during the actual classes, and in fact, over 30% do not participate. 9 in primary school learners, engagement in physical education classes is even lower than in high school. 9 original research article impact of a primary school-based nutrition and physical activity intervention on learners in kwazulu-natal, south africa: a pilot study abstract background. the opportunity for children to be physically active during school hours is rapidly decreasing in selected schools. this study evaluated the effects of a nutrition and physical activity (nap) intervention incorporated within the school curriculum. study design and methods. a prospective empirical pilot study with an intervention and an assessment of preand post-intervention fitness. learners completed a nap questionnaire and participated in a battery of fitness tests before and after intervention. setting. a purposive sample of four primary schools in kwazulunatal was selected by the provincial department of health. interventions. the nap intervention was designed to introduce various methods of physical activity and healthy nutritional habits within the school’s existing curriculum. classroom-based intervention materials were developed to provide cost-effective and, more importantly, a sustainable intervention. results. post-intervention results showed a significant increase (p<0.05) in the average number of sports participated in by each learner during physical education/life orientation periods. learners were motivated to participate in physical activity including games and sports during break times. a general increase in afterschool activities from preto post-intervention per learner was noted. conclusion. a school-based physical activity and nutrition intervention programme has the potential to increase the physical activity of learners and to a lesser degree their nutritional behaviour. correspondence: rowena naidoo university of kwazulu-natal edgewood campus private bag x03 ashwood, 3605 tel/fax: (031) 260 3676/260 3595 e-mail: naidoor3@ukzn.ac.za rowena naidoo (m sports science)1 yoga coopoo (d phil, facsm)2 estelle v lambert (ba, ms, phd (physiology))3 catherine draper (bsocsci (hons), ma (psychology), phd)3 1 department of life orientation, faculty of education, university of kwazulu-natal 2 centre for exercise science & sports medicine, faculty of health sciences, university of the witwatersrand 3 mrc/uct research unit of exercise science and sports medicine, department of human biology, university of cape town sajsm vol 21 no. 1 2009 � � sajsm vol 19 no. 4 2007 schools are an established setting for health-promotion activity, and in this setting may influence health-related beliefs and behaviours early in life before they are established as adult patterns. 10 an additional potential benefit is that by improving the health of school children, educational performance and learning may be enhanced. 11 patterns of physical activity acquired during childhood and adolescence are more likely to be maintained throughout one’s life span, thus providing the basis for active and healthy ageing. 12,13 therefore, school-based physical activity interventions are advantageous since programmes can become institutionalised into the regular school curriculum, staff development and other infrastructures. 14 international groups recommend that children should participate in at least 30 minutes of moderate to vigorous physical activity on most days, 12 although other consensus panels have recommended one 15,16 or more 17 hours of physical activity per day for children. a basic function of physical education is to engage learners in moderate to vigorous physical activity, a requirement for experiencing both health and motor skill development benefits. 18 by providing opportunities for physical activity, quality physical education can make important contributions to public health. 19 in addition to health and fitness benefits achieved through nutrition and physical activity interventions, studies have demonstrated the relationship between physical activity and academic performance. 20-22 the addition of physical education to the curriculum has resulted in small positive gains in academic performance. quasi-experimental data also suggest that allocating more curricular time to programmes of physical activity does not negatively affect academic achievement, even when time allocated to other subjects is reduced. 23 physical activity has been shown to demonstrate positive influences on concentration and memory 24 and on classroom behaviour. 23 in a recent review of successful school-based nutrition and physical activity interventions, the following common factors were present: incorporation of a nutrition-based curriculum by trained teachers, a physical activity programme/component, a parental/ family component, a food service or tuck-shop intervention, and with the intervention grounded in a relevant behavioural change theory. 25 there has been very little research on school-based programmes for the prevention of ncd in developing countries. however, schoolbased health promotion may have a greater impact in these settings, as social networks are often stronger, respect for teachers greater, and ncd risk factors less established among school children than in most developed countries. the present study implemented a school-based nutrition and physical activity (nap) intervention which was developed and designed specifically for the individual needs of the school to increase physical activity participation and promote healthy lifestyles among learners. the primary goals of the intervention were to (a) increase the physical activity of learners by implementing a classroom-based physical activity intervention and (b) promote physical activity during lunch-breaks and after school hours. additionally, the knowledge, attitudes and practices of learners towards physical activity before and after intervention were determined. this paper reports primarily on the physical activity component of the intervention. methods research design this study is a prospective empirical pilot study with an intervention and an assessment before and after intervention. sample a purposive sample of four primary schools in kwazulu-natal was selected by the kwazulu-natal department of health. schools were selected based on their easy accessibility and close proximity to each other (not more than 50 km away from each other). a total sample of 4 principals, 10 educators and 256 learners in grade 6 agreed to participate in the school-based intervention for a period of 6 months. there were no control schools, as the aim of this study was to examine the feasibility of the intervention and make amendments where applicable before the larger study is implemented. however, each participant served as their own control as there was a preand post-testing programme. permission to conduct the study in selected schools was granted from the kwazulu-natal departments of health and education. ethical clearance from the university of kwazulu-natal was granted for this study. informed consent forms were completed by all participants in the study. measuring instruments fieldwork at the schools involved both quantitative and qualitative methods of assessment. assessments were administered before and after intervention to all schools. quantitative assessments included the use of a learner questionnaire. the questionnaire aimed to determine the knowledge, attitudes and practices of learners towards physical activity and basic nutrition. physical activity and sports participation were captured by self-report and reflected the following time periods: club/team level during school hours, during physical education (pe)/life orientation (lo) lesson, and after school. in addition, learners participated in selected components from the eurofit 26 physical fitness test battery before and after intervention. the test battery included the following components: flexibility (sitand-reach), muscular endurance (30-second sit-ups) and explosive power (standing long jump). body weight and height were measured without shoes and body mass index (bmi) was calculated (kg.m -2 ). ‘overweight’ and ‘obesity’ were defined using the ageand sexspecific criteria 27 used by the centers for disease control and the world health organization. 28 a bmi greater than the 85th percentile is considered ‘at risk of overweight’ and a bmi greater than the 95th percentile is considered ‘obese’. all assessment tools were developed in conjunction with the university of cape town and were also used among learners in rural communities in limpopo and in alexandra township in gauteng. minor adjustments were made to the questionnaire to accommodate the language of the learners from kwazulu-natal. qualitative assessments included observation of learners’ physical activity and sports participation during lunch breaks; semi-structured interviews with the principals and selected grade 6 educators were conducted by the researchers before and after intervention. measures measures were conducted at the schools, during class hours and under direct supervision from researchers, educators, and school� sajsm vol 21 no. 1 2009 health nurses. all field workers were trained over a 2-week period in order to maintain consistency and reliability of testing. phases of the study (fig. 1) phase 1. this involved initial school visits by the researchers to brief the school principals and educators about the study. thereafter, interviews with principals and educators regarding their knowledge and attitudes towards physical activity and teaching methodologies of physical activity were investigated. selected educators attended training workshops on learning and implementation of the nap intervention. short courses on learners’ health, physical activity and nutrition were included. subsequent training of provincial school health nurses to assist in questionnaire administration, fitness testing and data collection was conducted by the researchers. phase 2. two weeks before the nap intervention was implemented by trained educators, questionnaires and fitness tests were administered to learners. the intervention was monitored by the research team for a 6-month period. phase 3. questionnaires were redistributed to learners and physical fitness was reassessed. principals and educators were interviewed by the researchers to gain feedback regarding the intervention regarding strengths, weaknesses, challenges and recommendations. intervention the nap intervention was designed to introduce various methods of physical activity and healthy nutritional habits within the school’s existing curriculum. classroom-based intervention materials were developed to provide cost-effective and, more importantly, a sustainable intervention. the key strategy was to integrate the nap intervention into the school curriculum by means of an inter-learning areas approach via trained educators. educators were trained to lead intervention activities, were provided with copies of all the activities and were allowed to choose which activity and, when necessary, to include such activities within particular lessons. the intervention was designed to be implemented by the school personnel with minimal external support to enable implementation after the study to be practicable and realistic. curriculum training workshops the research team conducted workshops for school educators on a voluntary basis. a 3-hour session before and during the pilot study and at least 2 monthly follow-up visits to schools by the research team was provided. grade-appropriate learning materials were designed and developed to incorporate nutrition and physical activity into selected learning areas, namely english, mathematics, natural science, social science and life orientation. workshops were ‘hands on’ with educators actively engaging in practical sessions. at the end of the session educators were given booklets containing classroom-based physical activities. educators were encouraged to promote physical activity outside the class, specifically during lunch breaks. nutrition schools were to increase the availability of healthy products (market low-fat food, fruit, juices and water) and decrease the availability of unhealthy products (fizzy drinks, selected sweets and chips) at all school tuck-shops if applicable. educators were to advise and prompt learners to purchase healthier food and drinks from school tuck-shops. learners were also provided with water bottles. school policies the intervention aimed to establish a health-promoting environment in the schools through physically active and healthy learners, educators and principals. school staff and learners also engaged in policy change efforts, such as developing a nutrition policy banning fizzy drinks in school. statistical methods a sub-sample of 185 questionnaires and fitness tests was analysed. data were missing for 71 learners due to learners not attending the post-intervention measures, inadequately filling out questionnaires or no longer attending the school. the data were analysed by the statistical package for the social sciences (spss) version 15. descriptive (means and standard deviations), and interferential (paired t-tests and chi-square tests of independence) statistics were used to test significant differences before and after intervention. a level of significance of p<0.05 was used for all interferential analyses. interviews were coded for content in order to determine common themes. results demographics of the learners the demographic data of all the learners are shown in table i. although 83% of learners live in brick homes and the majority have essential electrical appliances, it should be noted that an average of 6 individuals reside in a 4-roomed house. households varied from 2 to 20 occupants. therefore one can assume that the socio-economic status of the majority of learners in this study ranges from lowto middle-income groups. about 69% of learners travel distances greater than approximately 20 km to and from their school. learners’ modes of transportation include taxi, bus, train and foot. fig. 1. phases of the study. school visits interviews educator training workshop questionnaire & fitness testing questionnaire & fitness testing nap intervention interviews school health nurses training phase 1 phase 2 phase 3 fig. 1. phases of the study. sajsm vol 21 no. 1 2009 9 10 ’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´ sajsm vol 19 no. 4 2007 physical activity and sports participation before and after intervention results from the learner questionnaire determined physical activity and sports participation during selected time periods. physical activity at club/team level during school hours fig. 2 represents physical activity and sports participation of each learner at club/team level. it is evident that in every case, participation is significantly (p<0.05) greater after intervention than before intervention. the largest increases of 22% and 17% were in hockey and netball respectively. these increases were probably due to the fact that the survey was done during the hockey and netball season. incidentally, a 14% increase was found in dancing. this increase could be a direct result of the intervention as dance clubs were introduced into selected schools as part of the intervention programme. physical activity during physical education/life orientation lessons overall, results showed that after intervention there was a significant increase (p<0.05) in the average number of sports participated in by each learner during physical education/life orientation lessons. participation had increased considerably in cricket (6 23%), hockey (14 37%) and dancing (6 18%). this may also be as a result of different sports being offered in physical education/life orientation lessons at different times of the year. subsequently, the frequency of participation in physical activities in general was that 20% of learners did exercise ‘more than 5 times’ per week before intervention, while this figure increased to 43% after intervention. in addition, the percentage of learners who ‘do not participate’ had been reduced from 7% to 2% (p<0.05) after intervention. physical activity and sports participation after school fig. 3 shows a general increase in after-school activities from preto post-intervention per learner. this could be as a result of the intervention where educators were advised by researchers to stress the importance of regular physical activity during school as well as after school hours. there was a 10% increase in the number of learners performing chores around the house. additionally, learners participating in physical activity ‘more than 5 times’ per week after school had increased significantly (p<0.05) from 35% to 55% after intervention. physical activity and sports participation during school breaks reports from educators after intervention stated that learners were motivated to particpate in physical activity including games and sports during break times. as part of the intervention, educators supervised and provided learners with necessary equipment for activities. it was also reported by the educators that if physical activity or sports equipment is made readily available for learners during break times, learners’ physical activity or sports particiption is increased. educators reported an overall increase in the enthusiasm and the number of learners who particpated in games and sport during lunch breaks. the grade 6 learners’ enthusiasm created a new culture of games and play among other grades. fig. 3. participation in activities after school. 0 20 40 60 80 pl ay in g ga m es cy cli ng ch or es ru nn in g sw im m in g da nc ing sp or ts wi th fri en ds o th er physical activities p e rc e n ta g e o f l e a rn e rs pre-intervention post-intervention fig. 3. participation in activities after school. table i. learner demographics (n=1�5) demographics n (%) gender males 81 44 females 104 56 racial group black 154 83 coloured 15 8 indian 16 9 home language zulu 142 77 english 31 17 other (xhosa, sotho, afrikaans) 12 6 primary caregiver mother 105 57 grandmother 35 19 other (including brother/sister, aunt) 45 24 type of home brick home 153 83 mud homes 17 9 flats 15 8 homes consisting of four rooms, 165 89 excluding the bathroom television sets in households 175 90 radios in households 159 86 refrigerator in households 168 91 electric stove with oven in households 136 74 cook on open fires 43 22 gas stoves in households 43 23 paraffin stoves in households 37 28 grow vegetables or fruit trees 144 78 learners attend school in the same 57 31 neighbourhood in which they live fig. 2. participation of activities at club/team level. 0 10 20 30 40 50 60 so cc er cr ick et at hl et ics gy m na sti cs ru nn ing sw im m in g ho ck ey ba sk et ba ll ha nd ba ll ba se ba ll/s of tb al l da nc ing ne tb al l ru gb y ot he r physica l activitie s p er ce n at g e o f l ea rn er s pre-intervention post-intervention fig. 2. participation of activities at club/team level. 10 sajsm vol 21 no. 1 2009 sajsm vol 19 no. 4 2007 11 overall, it was estimated that during the 6 months of the nap intervention, physical activity among learners ranged from 45 to 215 minutes per week of moderate to vigorous physical activity during school hours. this calculated value reflects an accumulative integration of physical activities across various learning areas/ subjects. educators kept log books of the frequency, duration and perceived intensity of the learners’ physical activity during school hours. nutrition initially, the nutrition component of the intervention was not readily accepted by all schools as it was preconceived that change could lead to financial drawbacks. however, schools introduced gradual nutritional changes in tuck-shops and discovered that there were no negative financial implications. educators reported a greater turnover during the intervention, with healthier food and drink options in selected school tuck-shops. the researchers observed that healthier food and drink choices were now available in school tuck-shops, such as low-fat yoghurts and fruit. carbonated drinks were also eliminated from menus and substituted with energy drinks and juices. as part of the intervention, learners were provided with water bottles to encourage the drinking of water throughout the school day. principals reported that learners were motivated to carry the water bottles and regularly drank water during school hours. the researchers also observed that learners continued to purchase food and drinks as usual from school tuckshops although their original choices were unavailable. these alternatives appeared to be gladly accepted by learners, according to reports from principals and educators. fitness tests table ii shows the scores of the fitness tests conducted before and after the intervention. there were no significant changes in the flexibility (sit-and-reach) scores. there is an increase from 11% to 23% in the ‘>20’ sit-up category and an overall increase in the average number of sit-ups from 16 to 18. this increase in abdominal muscular endurance is significant (p<0.05) for both boys and girls. the explosive strength component (standing long jump) has remained unchanged at 1.30 m for the girls, with a 10 cm increase for the boys after intervention; this was not significant. all learners were below the 85th (‘at risk of overweight’) and 95th percentile (‘obese’) bmi. educator training workshops educators rated the training workshops useful and appropriate to the various learning areas and supported the approach of staff development. staff development, sample materials and on-site followup visits were valued by educators. educators preferred incremental improvements in their current curricula and instructional strategies rather than researchers providing structured curricula. improvements in current curricula were the approach of the nap intervention. educators were enthusiastic to learn and integrate new teaching strategies into their current areas of expertise. innovative classroom physical activity strategies were also shared by educators, in particular in the learning areas of english and mathematics. discussion overall results have shown that a multi-component behavioural health intervention can improve learners’ health behaviour and increase physical activity participation during formal instruction, lunch breaks and after school. in the south african national curriculum statement, 29 physical education is now incorporated into the learning area called life orientation. physical education or physical development and movement are learning outcomes of life orientation depending on the grade. these learning outcomes play an imperative role in providing children with physical activity for at least 30 60 minutes per week during school hours. however, this duration has not reached recommended standards of physical activity for child ren. 12,15-17 therefore additional measures of physical activity such as the nap intervention is suggested to help achieve physical activity recommendations and create an awareness of healthy lifestyles. a study 30 in the usa investigated whether children would compensate for school days of restricted physical activity opportunities by increasing activity levels after school. children did not compensate. results showed that after-school activity levels following an active day were actually higher than after-school activities following an inactive school day. if children are restricted or denied physical activity during school hours due to curriculum and/or school structures that decrease or eliminate physical activity, it appears that they will not voluntarily catch up on these lost opportunities of physical activity. 30 hence it is suggested that interventions that encourage sustained increase in physical activity participation among learners need to be incorporated into the school curriculum. finally, the possibility of inaccurate questionnaire data cannot be neglected. therefore it is necessary to note some limitations of this study. firstly, questionnaires were based on self-reports. this method can result in problems like memory bias, comprehensibility and concentration problems. secondly, a purposive sample for this study was not representative of all school children in kwazulu-natal, therefore generalisations cannot be made to grade 6 learners in other areas or provinces or to other grades. thirdly, only selected schools that had acquired health-promoting school status were part of the study. fourthly, the lack of a control group reduces the interpretability of the fitness data. in summary, this pilot study showed that by implementing a realistic and feasible intervention, physical activity participation of primary school learners can be increased during and after school. educators were trained to provide organised physical activity within the school curriculum as well as within the classroom. such activities did not hamper or change the primary outcomes of the lesson but instead provided educators with incremental improvements and instructional teaching strategies including physical movement in various learning areas. school and community programmes that promote regular participation in physical activity and optimal nutritional choices for table ii. fitness test scores before and after intervention for boys (n=�1) and girls (n=104) (mean ± standard deviation) components before intervention after intervention boys girls boys girls sit-and-reach 29.11±6.05 30.73±6.52 29.38±6.45 31.62±6.89 test (cm) sit-ups 18±3 15±4 20±4 16±4 standing 1.50±0.21 1.30±0.17 1.60±0.21 1. 30±0.19 broad jump (m) bmi (kg.m -2 ) 19.15±0.52 19.94±0.37 19.95±0.63 20.59±0.38 sajsm vol 21 no. 1 2009 11 12 ’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´ sajsm vol 19 no. 4 2007 children could be among the most effective strategies for reducing the public health burden of chronic diseases associated with sedentary lifestyles. programmes that provide children with the knowledge, attitudes, behavioural skills and confidence to participate in physical activity may establish a lifelong commitment to an active lifestyle. acknowledgement the kwazulu-natal department of health and education is thanked for supporting this project. the researchers would also like to thank the school-health nurses and officials from the kwazulu-natal department of health who provided substantial support during the study, as well as all participants. references 1. yusuf s, reddy s, ôunpuu s. global burden of cardiovascular diseases part i: general considerations, the epidemiologic transition, risk factors, and impact of urbanization circulation 2001;104:2746-2753. 2. wild s, roglic g, green a, sicree r, king h. global prevalence of diabetes: estimates for the year 2000 and projections for 2030. diabetes care 2004;7:1047-1053. 3. world health organization, ed. global strategy on diet, physical activity and health. fifty-seventh world health assembly; 2004 17 april. geneva: world health organization. 4. freedman d, khan l, mei z, dietz w, srinivasan s, berenson g. relation of childhood height to obesity among adults: the bogalusa heart study. pediatrics 2002;109(2):e23. 5. freedman d, khan l, serdula m, dietz w, srinivasan s, berenson g. the relation of childhood bmi to adult adiposity: the bogalusa heart study. pediatrics 2005;1:22-7. 6. armstrong m, lambert m, sharwood k, lambert e. obesity and overweight in south african primary school children – the health of the nation study. s afr med j 2006;96:439-444. 7. steyn n, labadarios m, maunder e, nell j, lombard c. secondary anthropometric data analysis of the national food consumption survey in south africa: the double burden. nutrition 2005:4 -13. 8. temple nj, steyn np, myburgh ng, nel jh. food items consumed by students attending schools in different socioeconomic areas in cape town, south africa. nutrition 2006;22:252-258. 9. mcveigh ja, norris sa, cameron n, pettifor j. associations between physical activity and bone mass in black and white south african children at age 9. j appl physiol 2004;97:1006-1012. 10. tones k, tilford s. health promotion: effectiveness, efficiency and equity. london: nelson thornes; 2001. 11. symons cw, cinelli b, james tc, groff p. bridging student health risks and academic achievement through comprehensive school health programs. journal of school health 1997;67(6):220-227. 12. sallis j, patrick k. physical activity guidelines for adolescents: consensus statement. pediatric exercise science 1994;6:302-314. 13. williams c, hayman l, daniels s, robinson t, steinberger j, paridon c. cardiovascular health in childhood: a statement for health professionals from the committee on atherosclerosis, hypertension, and obesity in the young (ahoy) of the council on cardiovascular disease in the young, american heart association. circulation 2002;106:143-160. 14. stone e, mckenzie t, welk g, booth m. effects of physical activity interventions in youth: review and synthesis. am j prev med 1998;15(4):298315. 15. cavill n, biddle s, sallis j. health enhancing physical activity for young people: statement of the united kingdom expert consensus conference. pediatric exercise science 2001;13:12-25. 16. dietary guidelines advisory committee. dietary guidelines for americans. washington, dc: us dept of health and human services and us dept of agriculture; 2000. 17. corbin c, pangrazi r. physical activity for children: a statement of guidelines. reston, va: national association for sport and physical education; 1999. 18. mckenzie t, sallis j, faucette n, roby j, kolody b. effects of a curriculum and inservice program on the quality of elementary physical education classes. res q exerc sport 1993;64(2):178-187. 19. sallis j, mckenzie t. physical educators role in public health. res q exerc sport 1991;62:124-137. 20. dwyer t, coonan w, leitch d, hetzel b, baghurst r. an investigation of the effects of daily physical activity on the health of primary school students in south australia. int j epidemiol 1983;12:308-313. 21. sallis j, mckenzie t, kolody b, lewis m, marshall s, rosengard p. effects of health-related physical education on academic achievement: project spark. res q exerc sport 1999;70:127-134. 22. shephard r, volle m, lavallee h, labarre r, jequier j, rajic m. required physical activity and academic grades: a controlled study. in: ilmarinen j, valimaki i, eds. children and sport. berlin: springer-verlag; 1984. p. 58-63. 23. sallis j, mckenzie t, alcaraz j, mckenzie t, hovell m. predictors of change in children’s physical activity over 20 months: variations by gender and level of adiposity. am j prev med 1999;16:222-229. 24. tomporowsi p. cognitive and behavioral responses to acute exercise in youths: a review. pediatric exercise science 2003;15:348-359. 25. hardeman w, griffin s, johnston m, kinmonth a, wareham n. interventions to prevent weight gain: a systematic review of psychological models and behaviour change methods. int j obes 2000;24:131-143. 26. eurofit. eurofit tests of physical fitness. 2nd ed. strasbourg; 1993. 27. pate p, davis c, robinson t, stone e, mckenzie t, young j. promoting physical activity in children and youth: a leadership role for schools. circulation 2006;114:1214-1224. 28. preventing and managing the global epidemic of obesity. report of the world health organization consultation of obesity. geneva: who; 1997. 29. department of education. revised national curriculum statement grades r-9 (schools). life orientation. pretoria; 2002. 30. dale d, corbin c, dale k. restricting opportunities to be active during school time: do children compensate by increasing physical activity levels after school? res q exerc sport 2000;71(3):240-248. 12 sajsm vol 21 no. 1 2009 original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the effectiveness of an online intervention in stimulating injurypreventive behaviour in adult novice runners: results of a randomised controlled trial e kemler,1 phd; mh cornelissen,1 msc; v gouttebarge,1,2,3,4 phd 1 dutch consumer safety institute, amsterdam, the netherlands 2 amsterdam umc, university of amsterdam, department of orthopaedic surgery, amsterdam movement sciences, meibergdreef 9, amsterdam, the netherlands 3 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 4 amsterdam collaboration on health & safety in sports (achss), amsterdam umc ioc research center of excellence, amsterdam, the netherlands corresponding author: e kemler (e.kemler@veiligheid.nl) running is one of the five most popular sports activities among adults worldwide and one of the most favourite sports for starting to become physically active[1]. in the netherlands, around 30% of the running population consists of novice runners who have less than one year of running experience[2]. in addition to its beneficial health effects, running is also associated with a high risk of musculoskeletal injuries. the incidence of running-related injuries (rris) is reported to range from three to 59 injuries per 1 000 exposure hours.[3-5] in particular, novice runners are at high risk of sustaining a rri, especially of the lower extremities.[2,3,6] risk factors for rris have been extensively investigated, but evidence remains contradictory and inconclusive. a history of previous injury in the past 12 months is reported to be the main risk factor for rris.[7,8] according to several review articles, half of all rris in runners are related to training errors.[9,10] furthermore, goal-setting seems to be of more importance to runners than a realistic training load. sports goal-oriented running and especially running in order to complete a certain distance plus participating in an event is associated with a higher risk of a rri.[11] rris among novice runners could be averted by favourable injury-preventive behaviour, such as modifying the training load.[9,10] however, novice runners might not be able to assess their training load properly, are probably not aware of the training errors they make, or simply ignore the signals their body gives due to their goal-setting behaviour in running.[11] to stimulate favourable injury-preventive behaviour in novice runners, such as performing a warm-up and cool -down routine, adjusting running volume/intensity, and responding to body signals (listening to your body), some interventions have recently been developed and have been used by runners with promising results, leading even to the prevention of rris.[12,13] hespanhol et al. showed that online tailored injury-preventive advice led to a reduction of rris among trail runners.[12] the intervention developed by adriaensens et al. was effective in stimulating injury-preventive behaviour among runners[13], but was time-consuming. a new online intervention (‘runfitcheck’) was developed to stimulate injury-preventive behaviour among novice runners. the objective of this study was to evaluate the effectiveness of runfitcheck on injury-preventive behaviour among adult novice runners. methods study design and participants a randomised-controlled trial (rct), with a follow-up period of five months (march 2017 – july 2017), was conducted, background: the online intervention runfitcheck was developed to stimulate injury-preventive behaviour among adult novice runners. objectives: this study evaluated the effectiveness of runfitcheck on injury-preventive behaviour among adult novice runners. methods: a randomised controlled trial was conducted among adult novice runners. the intervention group had access to the runfitcheck intervention, the control group performed their running activities as usual. one, three, and five months after enrolment, participants reported retrospectively what they had done regarding injury-preventive behaviour (operationalised as (i) using a (personalised) training schedule; (ii) performing strength and technique exercises; and (iii) performing a warm-up routine prior to running). relative risks (rr) and 95% confidence interval (95%ci) were used to analyse behavioural change. results: the intervention group (n=715) searched more often for information about a warm-up routine (rr 1.211; 95%ci 1.0801.357), and added more often strength exercises to their warm-up routine (rr 1.228; 95%ci 1.092-1.380). the intervention group performed more often running technique exercises compared to the control group (n=696) (rr 1.134; 95%ci 1.015-1.267), but less often strength exercises (rr 0.865 (95%ci 0.752-0.995). within the group of runners that did not perform any warm-up routine at enrolment (n=272), the intervention group started to perform a regular warm-up routine more often than the control group (rr 1.461; 95%ci 1.084-1.968). no significant results were found for using a training schedule. conclusion: the online intervention runfitcheck was effective in stimulating aspects of injury-preventive behaviour in adult novice runners, mostly related to a warm-up routine. trial registration: nl6225, registered april 24th 2007 retrospectively registered, https://www.trialregister.nl/trial/6225 keywords: behaviour, running, primary prevention, tailor-made, intervention s afr j sports med 2021;33:1-9. doi: 10.17159/2078-516x/2021/v33i1a11297 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a11297 https://orcid.org/0000-0003-3428-2969 https://orcid.org/0000-0002-0126-4177 https://orcid.org/0000-0002-3549-7091 original research sajsm vol. 33 no. 1 2021 2 consisting of an intervention and control group. the design of this study is described in detail elsewhere.[14] the study design and protocol were approved by the medical ethics review committee of the academic medical center (w16_335 # 16.417, amsterdam, the netherlands). the trial is registered in the dutch trial registry (id: nl6225). the group of participants consisted of adult novice runners. inclusion criteria were: (i) aged 18 years and older; (ii) having less than one year of running experience and/or not considering themselves as an experienced or very experienced runner. the choice for the combination of a time definition (less than one year of experience) and a definition based on feelings (not considering themselves as an experienced or very experienced runner) was made in accordance with running experts to concur with the dutch context. participants were recruited via social media networks (facebook, various websites, twitter, linkedin, newsletters) of the participating organisations. participants who completed all questionnaires were entered into a draw offering the possibility of winning a gift voucher to the value of €200 (±r3 500) for running clothes. all participants of the study provided informed consent online. protocol participants within the intervention group obtained access to the runfitcheck intervention.[13] no further conditions were applied to the use of the intervention. the runfitcheck intervention was developed according to an evidence-based (knowledge transfer scheme and intervention mapping) and practice-based (running experts) approach to stimulate injury-preventive behaviour among novice runners. more information on the development process and content of the runfitcheck is described in detail elsewhere[15] and in appendix a. the participants in the control group performed their running activities as usual. the main outcome measure of the study was injurypreventive behaviour by means of : (i) using a (personalised) training schedule; (ii) performing strength and technique exercises[16]; and (iii); performing a warm-up prior to running.[17] each of these injury-preventive behaviours was divided into preparatory and executional actions: (i) the training schedule consisted of two preparatory and one executional action, namely, searching for a training schedule, creating a personal training schedule, and using a general training schedule; (ii) strength and technique exercises consisted of two preparatory and two executional actions, namely, searching for both strength and technique exercises and executing both types of these exercises; (iii) the warm-up consisted of one preparatory and two executional actions: searching for information about a warmup routine for runners, performing a warm-up routine (extensive or otherwise), and adding strength exercises to a warm-up routine. an extensive warm-up is a warm-up routine in which the runner starts at a slow pace, performs strength exercises and sport-specific exercises. all injurypreventive behaviours were assessed through single answer questions from a pre-determined set of responses (yes/no/not applicable). participants were asked to fill in four online questionnaires (t0-t3). at enrolment (t0), participants were asked to report the injury-preventive behaviour (warm-up routine, strength and technique exercises, use of a (personalised) training schedule)) they usually performed before or during their running activities. additionally, participants were asked about their demographic characteristics (age in years, gender), running experience (in months), frequency per week of running and other sports activities in the previous three months, as well as any other injury-preventive behaviour. one month after enrolment (t1), three months later (t2), and five months later (t3), participants were asked to retrospectively report in detail, via an online questionnaire, what they had done in that time frame (one month between t1 and t0, two months between t2 and t1, two months between t3 and t2, respectively) in terms of preparatory and executional actions during their running activities. in previous literature, a 13% increase in injury-preventive behaviour among recreational adult runners (in this case, the inclusion of a warm-up) was found during a three-month follow-up period.[13] therefore, in this study, it was hypothesised that the runfitcheck intervention could lead to a 10% difference in favourable injury-preventive behaviour in the intervention group in comparison to the control group. a choice was made to use the word ‘difference’ instead of ‘increase’, as a difference between the two groups was considered as more important than only an increase. for example, if more runners in the intervention group execute favourable injury-preventive behaviour, but runners in the control group change their behaviour too, an increase will be found, but this is unlikely to be a statistically significant difference. to achieve 80% power with a significance level of 0.05, the sample size calculation revealed that 384 participants per study group were needed in this study. considering a response rate of 85% and a drop-out rate of 10% over the five months followup period, a total of at least 1 000 participants (500 per study group) in this study needed to be approached. as our main outcome measure for injury-preventive behaviour the study was divided into three different behaviours with several preparatory and executional actions, participants could perform one part of the outcome measure (e.g. performing a warm-up routine), while they did not perform the other behaviours. hence, after t0, all eligible participants were included in the study and allocated at random to either the intervention or control group, using a computerised random number generator (the aselect function in excel). no restrictions were imposed to achieve a balance between the groups in size or characteristics for the allocation, and simple randomisation was performed. also, concealed allocation was used. all steps in the randomisation process were performed by the principal researcher. neither the participants in the intervention group nor the researchers were blinded in this study. statistical analysis descriptive analyses (mean, standard deviation, frequency) original research 3 sajsm vol. 33 no. 1 2021 were conducted for the different baseline variables in both study groups. baseline variables were analysed for differences between the intervention and control groups (chisquare test, independent t-tests). for the executional actions, structural behavioural change was evaluated. a behaviour change is regarded as structural if runners changed their behaviour at a certain point in time, and continued to execute the behaviour until the end of the follow-up period, or if runners executed the behaviour at baseline, and continued to execute it until the end of the follow-up period. the relative risk (rr) and 95% confidence interval (95% ci) were calculated using the risk estimates within the chi-square analyses (only available for a 2x2 table) and were used to analyse behavioural change in the preparatory and executional injury-preventive actions between t0 and t3. analyses were performed according to the intention to treat analyses: (i) using a (personalised) training schedule; (ii) performing strength and technique exercises; (iii) performing a warm-up routine (extensive or otherwise). participants were included in the study until they dropped out, or after completing all four questionnaires. missing data were not included. for the analyses, those participants who executed the desired behaviour at baseline, and those participants who did not execute this behaviour at enrolment but did execute it during the follow-up period were grouped together and compared with participants who did not execute the desired behaviour at enrolment and who did not start or execute this behaviour during the follow-up period. in the sub-analyses, participants were only included if they did not perform the favourable injury-preventive behaviour at enrolment. relative risks and 95% ci were performed to reveal the ‘actual effect’ of the intervention on injury-preventive behaviour. for all analyses, significance was accepted at p<0.05. fig. 1. flow chart of the participants of the randomised prospective controlled trial. assessed for eligibility n=2148 (n= 1.842 ) excluded (n=737) not meeting inclusion criteria (n=425) double reactions (n=112) refused to provide permission (n=194)  age < 18 (n=6) analysed t0 (n=715) analysed t1-t3 (n=573) excluded from analysis (loss to follow-up before t1) (n=142) lost to follow-up (n= 237) did not start with questionnaire t1 (n= 142) did not start with questionnaire t2 (n= 58) did not start with questionnaire t3 (n= 37) drop out (n=220) did not complete questionnaire t1 (n= 166) did not complete questionnaire t2 (n= 12) did not complete questionnaire t3 (n= 42) did not complete questionnaire t3 (n= 42) allocated to intervention group (n=715) received allocated intervention (n=715) lost to follow-up (give reasons) (n=260) did not start with questionnaire t1 (n= 134) did not start with questionnaire t2 (n= 72) did not start with questionnaire t3 (n= 54) drop out (n=52) did not complete questionnaire t1 (n= 35) did not complete questionnaire t2 (n= 13) did not complete questionnaire t3 (n= 4) did not complete questionnaire t3 (n= 5) allocated to control group (n=696) analysed t0 (n= 696) analysed t1-t3 (n=562) excluded from analysis (loss to follow up before t1) (n=134) allocation analysis follow-up randomized (n=1411) enrolment original research sajsm vol. 33 no. 1 2021 4 results in total, 2 148 participants were interested in participating in the study, of whom only 1 411 were eligible for participation according to the inclusion criteria. of these eligible participants, 715 were randomly allocated to the intervention group and 696 to the control group. eighty percent of the participants (n=1 135) completed at least one of the follow-up questionnaires and were therefore included in the analyses. almost half of the participants completed all questions in all four questionnaires (46%; n=642). a complete flowchart of the participants is shown in fig. 1. of the 1 411 participants, 73% (n=1 025) were female, and the mean age was 38.1 years (sd=10.4; table 1). almost one-third of the participants had less than one year of running experience (30%). in the three months prior to the study, 14% of the participants had run less than once per week while 21% had run once per week on average. sixty-six percent had run at least twice per week. at baseline, 81% of the intervention group reported that they performed some kind of warm-up routine at the start of their training session, 19% performed an extensive warm-up routine in which they started to run at a slow pace and performed strength and sport-specific exercises. in the control group, 80% performed some kind of warm-up routine, while 20% performed an extensive warm-up routine. a general training schedule was used by 43% of the intervention group and 43% in the control group, and a personalised training schedule by 18% in the intervention group and 17% in the control group. more than half of the intervention group performed strength exercises (56%) and 31% performed exercises to improve their running techniques. in the control group, 56% performed table 1. baseline characteristics of the participants (n=1 411) characteristic intervention group (n=715) control group (n=696) total (n=1 411) gender, male 192 (26.9%) 194 (27.9%) 386 (27.4%) mean age in years (sd) 38.2 (10.5) 37.9 (10.3) 38.1 (10.4) running experience <6 months 6-12 months 12-18 months 18-24 months > 24 months 71 (9.9%) 140 (19.6%) 121 (16.9%) 105 (14.7%) 278 (38.9%) 61 (8.8%) 147 (21.1%) 113 (16.2%) 98 (14.1%) 277 (39.8%) 132 (9.4%) 287 (20.3%) 234 (16.6%) 203 (14.4%) 555 (39.3%) running frequency in previous three months less than once per week once per week twice per week or more 105 (14.7%) 137 (19.2%) 473 (66.2%) 87 (12.5%) 157 (22.6%) 452 (64.9%) 192 (13.6%) 294 (20.8%) 925 (65.6%) sport frequency in previous three months other than running not active in other sports less than once per week once per week twice per week or more 134 (18.7%) 140 (19.6%) 183 (25.6%) 258 (36.1%) 109 (15.7%) 121 (17.4%) 194 (27.9%) 272 (39.1%) 243 (17.2%) 261 (18.5%) 377 (26.7%) 530 (37.6%) data expressed as n(%) unless indicated otherwise. table 2. preparatory injury-preventive actions and executional injury-preventive actions undertaken by all runners over five months of follow-up intervention group control group rr (95% ci) using a (personalised) training schedule searched for a training schedule (n=970) 339 (79.8%) 420 (77.1%) 1.071 (0.941-1.218) created a personal training schedule (n=970) 209 (49.2%) 245 (45.0%) 1.077 (0.963-1.205) used a general training schedule (n=970) 180 (36.5%) 155 (33.0%) 1.070 (0.949-1.206) strength and technique exercises searched for information on strength exercises (n=961) 246 (59.0%) 374 (68.8%) 0.826 (0.730-0.936) searched for information on running techniques (n=961) 218 (51.5%) 274 (50.9%) 1.011 (0.904-1.131) performed strength exercises (n=962) 302 (71.9%) 422 (77.9%) 0.865 (0.752-0.995) performed running technique exercises (n=984) 255 (58.6%) 283 (51.5%) 1.134 (1.015-1.267) warm-up routine searched for information on a warm-up routine for runners (n=969) 240 (55.6%) 241 (44.9%) 1.211 (1.080-1.357) performed a warm-up routine (n=1 000) 399 (89.7%) 477 (85.9%) 1.155 (0.996-1.340) added strength exercises to warm-up routine (n=999) 219 (49.3%) 212 (38.2%) 1.228 (1.092-1.380) data expressed as n(%) which indicates the number and percentage of participants within each group that responded “yes” to each action. n represents the total number of participants of which information on the injury-preventive action is available. a runner could undertake one or more preparatory and executional injurypreventive actions. original research 5 sajsm vol. 33 no. 1 2021 strength exercises and 28% performed exercises to improve their running techniques. there were no significant differences between the two groups. after five months of follow-up, it turned out that intervention group searched more often for information about a warm-up routine (56% versus 45%; rr 1.211 (95% ci 1.0801.357); table 2), and added more often strength exercises to their warm-up routine (49% versus 38%; rr 1.228 (95% ci 1.092-1.380)). the intervention group performed running technique exercises more often compared to the control group (59% versus 52%; rr 1.134 (95% ci 1.015-1.267)), but less often strength exercises (72% versus 78%; rr 0.865 (95% ci 0.7520.995)). sub-analyses after five months of follow-up, within the group of runners that did not perform any warm-up routine at the start of the study (n=272; 70% female, mean age 35.8 years (sd 9.3)), the intervention group searched more often for information on a warm-up routine (54% versus 34%; n=194; rr 1.444 (95% ci 1.098-1.901)), performed a regular warm-up routine more often than the control group (47% versus 28%; n=196; rr 1.461 (95% ci 1.084-1.968)), and added strength exercises to their warm-up routine more often than the control group (33% versus 17%; n=195; rr 1.504 (95% ci 1.039-2.179) table 3). analyses within the group of runners that did not perform an extensive warm-up routine at the start of the study (n=882; 71% female, mean age 38.1 years (sd 10.2)) revealed similar results. the intervention group searched more often for information concerning a warm-up routine (56% versus 45%; n=859; rr 1.222 (1.083-1.380)), performed a regular warm-up routine more often than the control group (53% versus 40%; n=882; rr 1.257 (95% ci 1.112-1.421)), and added strength exercises to their warm-up routine more often (43% versus 30%; n=880; rr 1.290 (95% ci 1.127-1.478)) than similar runners in the control group. analyses within the group of runners that did not perform any running technique exercises at the start of the study (n=691; 72% female, mean age 38.7 years (sd=10.3)) revealed that the intervention group performed these exercises more often than the control group (41% versus 31%; rr 1.208 (95% ci 1.0421.400)). analyses within the group of runners that did not perform any strength exercises at the start of the study (n=426; 72% female, mean age 38.7 years (sd=10.3)) revealed that the intervention group performed these exercises less often than the control group (37% versus 50%; n=426; rr 0.790 (95% ci 0.669-0.932)). runners may have added strength exercises to their warm-up routine, or performed strength exercises at some other point in time during a week. the analysis showed that among those runners who did not perform any strength exercises at baseline (n=424), the intervention group added strength exercises to their warm-up routine more often (22% versus 11%), while the control group started to perform strength exercises at some other point of time during a week more often (30% versus 18%) (pearson’s chi-square 13.55, p=0.004). in both the intervention and control groups, around 19% added strength exercises to their warm-up routine and started to perform strength exercises at some other point in time during a week. forty percent in both groups did not perform any strength exercises at all. with regard to the use of a (personalised) training schedule, there were no significant differences. discussion in this study, the effectiveness of the online intervention runfitcheck in stimulating injury-preventive behaviour was evaluated among adult novice runners. similar results were table 3. preparatory injury-preventive actions and structural executional injury-preventive actions undertaken by runners over five months of follow-up intervention group control group rr (95% ci) using a (personalised) training schedule (no schedule at baseline) searched for a training schedule (n=376) 74 (46.3%) 91 (42.1%) 1.074 (0.900-1.283) created a personal training schedule (n=792) 134 (38.3%) 142 (32.1%) 1.130 (0.986-1.295) used a general training schedule (n=376) 17 (10.6%) 22 (10.2%) 1.021 (0.763-1.365) strength and technique exercises (no exercises at baseline) searched for information on strength exercises (n=426) 90 (48.4%) 139 (57.9%) 0.845 (0.712-1.003) searched for information on running techniques (n=668) 76 (26.4%) 115 (30.3%) 0.923 (0.802-1.062) performed strength exercises (n=426) 68 (36.6%) 120 (50.0%) 0.790 (0.669-0.932) performed running technique exercises (n=691) 124 (40.8%) 121 (31.3%) 1.208 (1.042-1.400) warm-up routine (no routine at baseline) searched for information on a warm-up routine for runners (n=194) 45 (53.6%) 37 (33.6%) 1.444 (1.098-1.901) performed a regular warm-up routine (n=196) 41 (47.1%) 31 (28.4%) 1.461 (1.084-1.968) added strength exercises to warm-up routine (n=195) 28 (32.6%) 19 (17.4%) 1.504 (1.039-2.179) warm-up routine (no extensive routine at baseline) searched for information on a warm-up routine for runners (n=859) 216 (56.4%) 215 (45.2%) 1.222 (1.083-1.380) performed a regular warm-up routine (n=882) 207 (52.8%) 197 (40.2%) 1.257 (1.112-1.421) added strength exercises to warm-up routine (n=880) 166 (42.5%) 146 (29.9%) 1.290 (1.127-1.478) data expressed as n(%) which indicates the number and percentage of participants within each group that responded “yes” to each action. n represents the total number of participants of which information on the injury-preventive action is available. a runner could undertake one or more preparatory and executional injury-preventive actions. original research sajsm vol. 33 no. 1 2021 6 found in analyses in which the whole study population was included, and in analyses in which runners were included who did not perform a specific type of injury-preventive behaviour at enrolment. performing a warm-up routine at the start of a training session was one of the important elements of the runfitcheck intervention. in this intervention, the injury-preventive advice on a warm-up consisted of a short introduction on the benefits of performing a warm-up routine, followed by an instruction video with a voice-over of a warmup routine for runners (lasting five minutes). the video was immediately accessible on the runner’s mobile phone, tablet or computer. providing an easily accessible video thus seems to be effective in stimulating favourable injury-preventive behaviour. however, several aspects of the results with regard to the warm-up routine need to be addressed. a high percentage (81%) of runners performing any kind of warm-up routine at baseline might have made it difficult to identify the effect of the intervention as only 20% could benefit from it. this might have led to increasing ceiling effects of the intervention. however, with a total of 2.1 million runners in the netherlands in 2013, of whom 620 000 were novice runners[2], we believe that many runners could benefit from the intervention. as previously mentioned, 81% of the runners performed some kind of warm-up routine at baseline. the details of regular and extensive warm-ups were starting at a slow pace, stretching, and sport-specific exercises. as stretching is not regarded as beneficial for injury prevention in runners [10,17,18], it is arguable how many of these 81% actually performed this in their warm-up routine. for this reason, we performed other analyses with those runners who did not perform an extensive warm-up routine at baseline. these analyses showed that runners in the intervention group who did not perform an extensive warm-up at baseline performed a regular warm-up routine more often than runners in the control group (53% versus 40%; n=882; rr 1.257 (95% ci 1.1121.421)). they also added strength exercises to their warm-up routine more often (43% versus 30%; n=880; rr 1.290 (95% ci 1.127-1.478) when compared to similar runners in the control group. although we do not know the quality of the warm-up routine that the runners performed, we do know that around 80% of the runners in the intervention group added strength exercises to this routine, as did 75% of the runners in the control group. for future studies, we believe it is important to define what a warm-up routine should be or put more effort in determining the quality of a warm-up routine (e.g. by questioning in more detail what runners do or have changed in their warm-up routine). in contrast to injury-preventive aspects of a warm-up routine, the intervention group performed strength exercises less often than the control group. the results with regard to the inclusion of strength exercises surprised the research team, especially as the intervention group added more strength exercises to their warm-up routine. a possible explanation for this result might be that in the online questionnaires for both the intervention and control groups, the questions related to this topic were not completely identical. the intervention group was asked whether they had started to perform the strength exercises available in the intervention. information on the performance of other strength exercises was, unfortunately, not collected. the control group was also asked if they performed any kind of strength exercises. this could have influenced the results of this part of the study. also, an additional analysis revealed that the moment the runners performed the strength exercises, caused the difference between the two groups. runners in the intervention group who did not perform any strength exercises at baseline added strength exercises to their warm-up routine more often (22% versus 11%), while runners in the control group started to perform strength exercises at some other point more often in time (29% versus 18%) (pearson’s chi-square 13.546, p=0.004). forty percent in both groups did not perform any strength exercises. although these additional analyses showed that the negative outcome of the intervention with regard to strength exercises is probably actually not that negative at all while a positive outcome could not be demonstrated either. in addition to the positive effects of their warm-up routine and running technique exercises, runners in the intervention group were requested more often to search for more information on injury prevention in running. they reported visiting two dutch websites, one for the dutch consumer safety institute which consisted of information on the prevention of sports injuries, including rris (23% versus 8%; rr 1.964 95% ci 1.523-2.534), and a website of the royal dutch athletics association (knau), compared to runners in the control group (29% versus 18%, rr 1.365 95% ci 1.162-1.605). these websites were accessible in the runfitcheck intervention via direct links to the specific websites. for the preparatory and executional actions in the training schedules, no differences were found between the intervention and control groups. if we did find any differences, they were possibly difficult to interpret as negative or positive. training errors are mentioned as a main cause of rris[9,10], although a recent review found that very limited evidence exists to support the notion that changes (increases and decreases) in training load are associated with injury development[18]. fields et al. stated in their review that excessive mileage and changes in training schedule are associated with an increased incidence of rris. since each person’s body responds differently to the stress caused by running, individualised training programmes are recommended[10]. linton and valentin, on the contrary, found in their study that in the first year of running, runners using a self-devised training programme were more likely to be injured compared with runners using a structured programme [19]. although a self-devised training programme is not the same as a personalised training programme, it is difficult to determine what a good programme or training schedule is for a runner. furthermore, we do not have enough detailed information to judge the training schedules the runners in our study used. we do know that it was either a personalised schedule or a regular training schedule, but we do not know the exact content of the schedules used, which is a limitation in our study. several other methodological considerations of our study can be addressed. firstly, we included novice runners in our study identified according to a combination of two definitions: one original research 7 sajsm vol. 33 no. 1 2021 based on time (less than one year of experience), and one based on feelings (not considering themselves as an experienced or very experienced runner). when developing the research design, the definition of novice runners was extensively discussed with running experts of the royal dutch athletics federation. the research group, together with these running experts, believed the definition based on time was too narrow and did not fit well enough with the dutch running population. hence, we used a combined definition for a novice runner. however, as we do not know how and why runners judge themselves as they did, our results could have been influenced by the use of our definitions. for further studies, and the design of injury preventive programmes, it would be of interest to explore how and why sports participants, including runners, judge themselves as they do secondly, the original sample size calculation revealed that at least 1 000 novice runners were needed to be enrolled in the study. achieving such a high number of participants was challenging. several methods were used to enhance enrolment, such as social media (facebook, linkedin and twitter), newsletters from the knau (digital) and the magazine runner’s world (in print and digital), and the possibility to pre-register for the study. furthermore, participants who completed all questionnaires were entered into a draw in which they could win a gift voucher to the value of €200 (±r3 500) for running clothes. the methods worked, since 2 148 volunteered for the study, of whom 1 411 were eligible. however, the adherence to the study after five months of follow-up was relatively low (46%). the draw to win a voucher for running clothes could be a possible reason for the participants’ low adherence rate (only wanting to participate to win the voucher, but not to complete the study). another reason for low adherence could be the running population itself, in particular novice runners. an important aspect of being a novice runner or novice athlete is the aspect of being “unconscious incompetent”, referring to the first stage of the ‘four stages of competence’ model. [20] novice athletes, or at least most of them, do not understand or know how they can prevent injuries and do not necessarily recognise the importance of prevention. as this trial focused on changing injury-preventive behaviour in novice runners, they might have denied the usefulness of the intervention and study and dropped out. additional analysis, however, did not reveal relevantly significant differences in characteristics between runners who dropped out of the study or who were lost to follow-up, and those who completed all questionnaires. therefore, we still consider our results as meaningful. finally, we want to address the potential impact of recall bias on the calculation of running exposure. to define the running exposure of participants, we gathered information on running frequency. running frequency is, however, not the sole outcome measure for running exposure. to get more insight into running exposure, it is important to gather information on running duration and/or distance as well as frequency. the potential of recall bias prevented us from doing so in this study. also in our study, at t2 and t3, participants had a twomonth recall period, causing a possible recall bias. a recall period of one–three months is recommended for injury questionnaires[21], similar to that used in our study. however, we focused on injury-preventive behaviour which could be more problematic to recall. hence, a shorter recall period or a prospective study is advised for future studies, but researchers should be aware of the balance between research load for participants (and possible drop-out) and (lack off) recall bias. a strength of our study is the design used. a rct, when well designed, provides the strongest evidence of any epidemiological study design, and is usually used to evaluate the effectiveness of an intervention in an experimental setting. in this study, however, we did not evaluate the effectiveness of the runfitcheck intervention in an experimental setting, but in a real-world setting, which in our opinion is another strength of the study. it is well-known that it is difficult to transfer interventions whose efficacy has been proved into real-world settings (efficacy versus effectiveness)[22]. with the development of runfitcheck, the research group made the assumption that an increase in injury-preventive behaviour will ultimately lead to a decrease in rris. our main focus was therefore on stimulating injury-preventive behaviour rather than preventing rris, as adjustment of behaviour is crucial before prevention of rris is even possible. in our study, participants in the intervention group were given access to the runfitcheck intervention, but no further conditions were applied to the use of the intervention. we demonstrated effects of the runfitcheck intervention in stimulating some aspects of injury-preventive behaviour among adult novice runners, indicating that an intervention like runfitcheck actually could work in ‘the real world’. although we did find some positive outcomes, it is still unclear whether the results of our intervention with benefits of a warm-up routine are clinically relevant, and if these are enough to prevent rris. as mentioned in the introduction, rris among novice runners could be prevented by favourable injury-preventive behaviour such as modifying the training load [9,10]. in our intervention we tried to focus on the physical load-taking capacity of runners and the motivation of runners to achieve their running goals to stimulate runners to modify their training load when necessary. performing a warm-up routine was one of our suggestions. although we did stimulate injury-preventive behaviour, this might not be enough to prevent rris. the transition from injury-preventive behaviour to the prevention of rris needs to be addressed in another randomised controlled trial. the starting point of the development of the runfitcheck intervention was a potentially effective but time-consuming – and therefore unattractive and complex – intervention for injury prevention in running[13], and information on the number and severity of running-related injuries in the netherlands. adriaensens et al. developed a tailor-based online injuryprevention intervention (website) with informational videos about the aetiology and mechanisms of rris, combined with injury-preventive advice, and an online questionnaire. this online questionnaire allowed the website to provide tailored feedback based upon a series of predefined questions that create a personal risk profile of the user[13]. a 13% increase in original research sajsm vol. 33 no. 1 2021 8 injury-preventive behaviour (in this case, the inclusion of a warm-up) was found over a three-month follow-up period.[13 although the intervention developed by adriaensens et al. was effective, the online questionnaire for tailored feedback was time-consuming. therefore, the dutch consumer safety institute developed the runfitcheck intervention to encourage injury-preventive behaviour among novice runners without the associated time burden and was indeed able to induce a 10% difference in several aspects of injury-preventive behaviour in runners in favour of the intervention group. furthermore, the results of this study showed that the realisation of a difference of 10% in injury-preventive behaviour is feasible using an online intervention. conclusion the online intervention runfitcheck was effective in stimulating aspects of injury-preventive behaviour in adult novice runners, mostly related to a warm-up routine. the realisation of a 10% difference in favourable injury-preventive behaviour is feasible with an online intervention. conflict of interest and source of funding: the authors declare no conflict of interest. this project was partly funded by the netherlands organization for health research and development. availability of data and material: the datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. our institution is exploring the possibilities of data sharing, but has not formulated a final policy on this subject. author contributions: all authors were responsible for the conceptualization of the idea and the preparation of the study proposal. ek was responsible for the data collection, data analyses, interpretation of the data, and preparation of the manuscript. mc was responsible for the data collection, data analyses, and the critical review of the manuscript. vg was responsible for the interpretation of the data and preparation of the manuscript. all authors read and approved the final manuscript. references 1. hulteen rm, smith jj, morgan pj, et al. global participation in sport and leisure-time physical activities: a systematic review and meta-analysis. prev med 2017; 95:14-25. [doi: 10.1016/j.ypmed.2016.11.027] [pmid: 27939265] 2. kemler e, blokland d, backx f, et al. differences in injury risk and characteristics of injuries between novice and experienced runners over a 4-year period. phys sportsmed 2018; 46(4):485-491. [doi: 10.1080/00913847.2018.1507410] [pmid: 30071170] 3. buist i, bredeweg sw, bessem b, et al. incidence and risk factors of running-related injuries during preparation for a 4mile recreational running event. br j sports med 2010; 44(8):598-604. [doi: 10.1136/bjsm.2007.044677] [pmid: 18487252] 4. gent van rn, siem d, van middelkoop m, et al. incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. br j sports med 2007; 41(8):469-480. [doi: 10.1136/bjsm.2006.033548] [pmid: 17473005] 5. kluitenberg b, van middelkoop m, verhagen e, et al. the impact of injury definition on injury surveillance in novice runners. j sci med sport 2016; 19(6):470-475. 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[doi: 10.1097/00042752-200501000-00004] [pmid: 15654186] 17. behm dg, blazevich aj, kay ad, et al. acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review. appl physiol nutr metab 2016; 41(1):1-11. [doi: 10.1139/apnm-2015-0235] [pmid: 26642915] 18. thacker sb, gilchrist j, stroup df, et al. the impact of stretching on sports injury risk: a systematic review of the literature. med sci sports exerc 2004; 36:371-378. [doi: 10.1249/01.mss.0000117134.83018.f7] [pmid: 15076777] 19. linton l, valentin s. running with injury: a study of uk https://www.ncbi.nlm.nih.gov/pubmed/30268637 https://www.ncbi.nlm.nih.gov/pubmed/30268637 https://www.ncbi.nlm.nih.gov/pubmed/30268637 https://doi.org/10.34045/ssem/2014/17 https://doi.org/10.2196/resprot.9708 https://www.ncbi.nlm.nih.gov/pubmed/29853263 original research 9 sajsm vol. 33 no. 1 2021 novice and recreational runners and factors associated with running related injury. j sci med sport 2018; 21(12):1221-1225. [doi: 10.1016/j.jsams.2018.05.021] [pmid: 29853263] 20. broadwell mm. teaching for learning (xvi). the gospel guardian 1969; 20(41):1-3 https://edbatista.typepad.com/files/teaching-for-learningmartin-broadwell-1969-conscious-competence-model.pdf 21. harel y, overpeck md, jones dh, et al. the effects of recall on estimating annual nonfatal injury rates for children and adolescents. am j public health 1994; 84(4):599–605. [doi: 10.2105/ajph.84.4.599] [pmid: 8154563] 22. finch c. a new framework for research leading to sports injury prevention. j sci med sport 2006; 9(1-2):3-9. [doi: 10.1016/j.jsams.2006.02.009] [pmid:16616614] https://www.ncbi.nlm.nih.gov/pubmed/29853263 https://www.ncbi.nlm.nih.gov/pubmed/29853263 introduction obesity is a global 15 and local 30 epidemic and is associated with numerous comorbidities, 28 such that cardiovascular disease, hypertension and diabetes are a global and regional threat. 17,45,47 there seems to be agreement that the successful implementation of public health initiatives will require some degree of social responsibility from private industry. 42,46 for instance, some fast-food chains have adjusted their products to cater for healthier food choices and have included step counters or pedometers in their product mix to promote greater public awareness of the importance of a physically active lifestyle and to improve their public image. 13 nationally, several major companies have launched campaigns in 2005 using pedometers or step counters to promote an active lifestyle. in 2005, kellogg’s south africa launched the kellogg’s special k step counter (kl), 19 and discovery health introduced the vitality pedometer (vt) as part of their vitality programme. 12 these south african initiatives are in agreement with international health promotion programmes as seen in australia, 1 europe 41 and north america. 3 the kellogg’s promotion encourages pedometer users to increase their daily ambulatory activity by 2 000 steps over and above their usual ambulation level, 19 while discovery health launched a similar 10 000 steps programme. 12 although the marketing initiatives of kellogg’s south africa and discovery health are laudable, the accuracy and longevity of the pedometers are not reported. calibration studies have found that the accuracy 5,9,21,22,25,32 and longevity 24 of pedometers vary considerably between brands. recent validation trials of promotional pedometers in europe 10 and north america 14,37 have found poor instrument accuracy and consistency. these studies concluded that poor quality promotional pedometers detract from the public health message of a physically active lifestyle. 10,14,37 it is important to note that the potential for substantial error and misclassification is possible if the pedometers are found to be inaccurate and unreliable or fragile. erroneous pedometer readings could have a significant effect on the awarding of ‘points’ or incentives in the discovery vitality original research article pedometer step counting in south africa: tools or trinkets? ian cook (ba (phys ed) hons, bsc (med) hons) department of kinesiology and physical education, university of limpopo, polokwane abstract objectives. this study addressed (i) the accuracy of measuring ambulatory signals and (ii) the susceptibility to nonambulatory signals, of the discovery vitality pedometer (vt) and the kellogg’s special k step counter (kl) compared with three research-grade pedometers (dw: yamax digiwalker sw-401, mti: mti actigraph am-7164-2.2 , nl: new lifestyles nl 2000). design. one hundred instruments (20 instruments/brand) were tested at five level walking speeds on a motorised treadmill (3.24, 4.02, 4.80, 5.64, 6.42 km.hr -1 ) and during motor vehicle travel on tarred roads (62.9 km). results. the kl was highly variable across all speeds, while the vt tended to be variable at the lowest speed. the dw, nl and vt significantly underestimated steps below 4.80km.hr -1 (41 94%, p < 0.02) but accuracy improved at speeds ≥ 4.80 km.hr-1 (98 102%). the kl displayed the highest variability (60% inter-instrument variance) followed by the vt (10% inter-instrument variance). the research-grade pedometers were the least variable (0 1% inter-instrument variance). at 4.80 km.hr -1 , all research-grade pedometers measured within a 10% margin of error compared with the 90% of vt units and 42% of kl units. the vt was significantly more resistant to nonambulatory signals than the dw (p < 0.01). the kl was the most variable in its response to non-ambulatory signals while the nl was the most consistent. the mti detected the most non-ambulatory signals (p < 0.05). conclusions. the kl should not be used as a promotional pedometer. the vt achieved the minimum standards required of a promotional pedometer. further testing is correspondence: ian cook department of kinesiology and physical education university of limpopo (turfloop campus) po box 459 fauna park 0787 polokwane tel+fax: +27 15 268 2390 e-mail: ianc@ul.ac.za required for longevity, and performance under free-living conditions. sajsm vol 18 no. 3 2006 67 pg67-78.indd 67 9/21/06 12:21:50 pm 68 sajsm vol 18 no. 3 2006 lifestyle programme 12 and kellogg’s special k challenge. 19 for instance, with an 80% accuracy level, 10 000 steps.day -1 could be measured as 8 000 steps.day -1 or 12 000 steps. day -1 . in other words, a participant could be classified as low active or highly active for the same pedometer reading. 34 customer reviews of the discovery vt have reported wide discrepancies between pedometers ranging from 5 000 steps to more than 40 000 steps. one customer review reported the pedometer recording approximately 1 out of every 25 steps (4% accuracy level). 11 therefore, the objectives of this study were firstly to determine the accuracy of measuring ambulatory signals, and secondly to evaluate the susceptibility to non-ambulatory signals, of the vt and the kl pedometers as opposed to research-grade pedometers. methods study design five brands of pedometers, of which three are researchgrade instruments, were tested while: • walking at five level speeds on a motorised treadmill, • and during motor vehicle travel on tarred roads. for each pedometer brand 20 units were tested so that 100 pedometers were tested in total. for the purposes of this investigation a research-grade pedometer was defined as an instrument that has been found to be valid and consistent in its measurement of ambulatory activity, and as such is routinely used in descriptive and experimental studies which investigate aspects of physical activity and health. promotional pedometers are defined as instruments that sporadically appear in the public domain through corporate initiatives but have not undergone any form of quality control conducted either by the corporate or an independent institution prior to distribution. the study was approved by the ethics committee of the university of limpopo (turfloop campus) and signed informed consent was obtained from subjects prior to participation in the study. fig. 1. internal details of the step-sensing mechanisms of research-grade and promotional pedometers. mti = mti actigraph am-7164-2.2, nl = new lifestyles nl 2000, dw = yamax digiwalker sw-401, vt = discovery vitality pedometer, kl = kellogg’s special k step counter, fl = flora comrades step counter (the fl pedometer could not be obtained in time for the completion of the study, but it is included for comparative purposes, see discussion). key to internal details: 1 = battery, 2 = axis about which lever arm turns, 3 = lever arm, 4 = mass, 5 = magnet, 6 = magnetic reed switch, 7 = metal contacts, 8 = dampened contacts, 9 = hair spring, 10 = coiled spring, 11 = uni-axial, piezo-electric accelerometer mechanism (horizontal cantilevered beam with a mass on the end, piezo-electric crystal). pg67-78.indd 68 9/21/06 12:21:54 pm sajsm vol 18 no. 3 2006 69 pedometers the validity, reliability or longevity, construction and rating of these or similar pedometers have been studied and reviewed extensively elsewhere. 33,43 as a qualitative assessment of pedometer quality, 33 fig. 1 details the internal construction of the pedometers. the kl (6.4 cm x 4.8 cm x 2.2 cm, 21 g) uses a hair spring and lever arm (fig. 1) but does not incorporate any algorithms within the microprocessor to exclude non-ambulatory signals. the control buttons are not covered, raising the possibility of inadvertently resetting or stopping the unit. the south african promotion is based on a similar promotion in the united kingdom. 18 the pedometer was obtained from kellogg’s south africa. 19 the vt (2 cm x 5.3 cm x 3.6 cm, 16 g) can be obtained from discovery vitality partners 12 or online. 11 the vt step-counting mechanism also uses a hair spring and lever arm (fig. 1). the vt incorporates an algorithm within the microprocessor to filter signals so as to exclude non-ambulatory signals. because the control buttons are not covered the possibility exists of inadvertently resetting the unit. the yamax digiwalker (dw, model sw-401, new lifestyles inc., mo, usa) (5 cm x 3.8 cm x 2 cm, 21 g) uses a coiled-spring mechanism and lever arm to detect steps (fig. 1). the dw does not utilise an algorithm to filter signals for non-ambulatory movement. a cover over the control buttons prevents the unit from being inadvertently reset or stopped. the dw is considered accurate 5,6,9,21,32 and durable, 24 and has been used for large-scale surveys 4,36 and in experimental trials. 16,27 the dw is a popular brand of pedometer and has been used in public health initiatives similar in concept to the kellogg’s and discovery initiatives. 1 the new lifestyles nl 2000 (nl, new lifestyles inc., mo, usa) is slightly larger and heavier than the dw (1.9 cm x 3.5 cm x 5.7 cm, 31 g). instead of a spring mechanism, the nl pedometer consists of an accelerometer-type mechanism (fig. 1). an algorithm in the microprocessor is used to filter the signal from the piezo-electric crystal in order to exclude non-ambulatory movement. the control buttons are covered, preventing the unit from being inadvertently reset or stopped. the nl is considered one of the most sophisticated pedometers marketed for public use and has been shown to have accuracy comparable to that of research-grade uniaxial accelerometers. 9,31,32 as with the kl, vt and dw, the output (total number of steps recorded) for the nl is read off a small lcd screen. the mti actigraph (mti, model am-7164-2.2, mti health services, fl, usa) (5 cm x 4 cm x 1.5 cm, 43 g) is a research-grade movement monitor 44 incorporating a uni-axial accelerometer and appropriate signal filters (fig. 1). the mti pedometer mode has been used as a criterion for pedometer validation 21,22,44 and in experimental trials. 20 there are no external buttons and the monitor output cannot be directly viewed but must be downloaded to an ibm compatible computer via an interface unit for further analysis using appropriate software (mti actisoft analysis software for windows version 3.2). the number of steps recorded for the particular epoch period, e.g. total number of steps in 1 minute, is used to determine the total number of steps over the period of recording. study protocol part 1. accuracy the accuracy with which the pedometers (dw, kl, mti, nl, vt) could measure 100 steps was evaluated on a calibrated motorised treadmill (johnson jet-7000). one female subject (37 years, body mass: 65.0 kg, stature: 165 cm) wore pedometers (dw, kl, mti, nl, vt) on the left side during three trials (the left side was chosen for ease of measurement during the trials, and because the pedometers were not all available at the same time, three trials had to be conducted). each trial consisted of 20 walking bouts, and 1 walking bout included five speeds (3.24, 4.02, 4.80, 5.64, 6.42 km.hr -1 or 54, 67, 80, 94, 107 m.min -1 ). corresponding approximate energy expenditures for these walking speeds is 2.5 mets, 3.0 mets, 3.3 mets, 4.0 mets and 5.0 mets, respectively (metabolic equivalents, 1 met = 1 kcal.kg -1 .min -1 ). 2 this protocol is analogous to testing all the pedometers on a single mechanical calibration rig 7,26 and is in agreement with the ‘longevity’ protocol of mckenzie et al. 24 that used one subject walking on a treadmill, over a number of trials. for the first trial, the mti and the dw were placed over the midline of the thigh and the kl monitors were placed approximately 15 cm to the left of the central line of the waist as per manufacturers' instructions. thus starting from the midline of the left thigh, the order of pedometer placement from back to front was mti, dw and kl. for the second and third trials, the subject wore the vt and nl, respectively, over the centre of the left thigh as per manufacturers’ instructions. the placement of the dw/mti combination was such that the pedometers were positioned directly next to each other, with the midline of the thigh separating the two pedometers. both pedometers were ~1 cm from the midline of the thigh. there are no data to suggest that this distance from the midline of the thigh could affect pedometer output. in fact, some studies have placed the dw and mti concurrently on the left and right side during treadmill validation trials. 21 the pedometers were securely attached to a nylon belt which clipped around the subject’s waist. the subject walked at five speeds (3.24, 4.02, 4.80, 5.64, 6.42 km.hr -1 ) with one or more pedometers, after which a new pedometer was attached to the subject’s waist and the five-speed calibration process was repeated. the walking speeds were not randomised but applied in ascending order starting at the lowest speed. the subject was well experienced in walking and running at low and fast speeds on a motorised treadmill. in addition, the subject was trained to step on or off the moving treadmill belt quickly and to stand quietly until instructed to step onto the treadmill belt again. the subject was also habituated to using the treadmill safety rails as little as possible when pg67-78.indd 69 9/21/06 12:21:54 pm 70 sajsm vol 18 no. 3 2006 stepping onto the treadmill belt. for each trial the treadmill belt was adjusted to the proper speed while the subject stood quietly at the side of the treadmill. at the command of the investigator, the subject stepped onto the treadmill belt and started walking. using a tally counter, 100 steps were counted. the last step was taken so that the subject stepped off the treadmill belt and stood quietly for at least 20 seconds while the treadmill speed was adjusted for the next walking speed and the readings from the pedometers (dw, kl, nl, vt) were recorded and the units reset. prior to the first calibration session the mti pedometers were activated and the recording epoch set at 5 seconds. before each calibration walk, the subject stood quietly on the treadmill for 20 seconds to ensure a ‘washout’ prior to the next calibration walk. after the full calibration session, the data were downloaded from the mti units to an ibm-compatible computer via an interface unit for further analysis. the accuracy of the pedometers to measure 100 steps was expressed as a percentage (100 steps = 100%). a spirit level was used to ensure that the treadmill was level. the treadmill speed was calibrated before and after each calibration session by measuring the belt length (3.305 m) and the time it took to complete 25 revolutions at five speeds (3.24, 4.02, 4.80, 5.64, 6.42 km.hr -1 ). part 2. susceptibility to non-ambulatory signals to evaluate the effect of motor vehicle travel on pedometer output, 100 pedometers (20 instruments from 5 pedometer brands; dw, kl, mti, nl, vt) were randomly fastened to a custom-made wooden rig (width: 74 cm x length: 44.5 cm x height: 9.5 cm, mass: 3.7 kg) along 10 columns and 10 rows. the rig was placed on the rear seat of a light motor vehicle (ford ikon 1.6i lx, 2004 model) and centered along the longitudinal axis of the motor vehicle. a 50 kg dead weight was placed on top of the wooden rig to prevent undue movement and vibration. the front passenger seat was unoccupied. prior to the ride the pedometers were reset (dw, kl, nl, vt) and activated (mti, 1 minute recording epoch). the trip was conducted in and around a metropolitan area on tarred roads to simulate usual driving patterns (variable and constant speed). after the ride the data (total number of steps) were recorded (dw, kl, nl, vt) or downloaded (mti) to an ibm-compatible computer via an interface unit for further analysis. the total number of steps recorded during the ride were divided by the total distance covered (km) and expressed as steps.km -1 . to obtain an accurate measure of the trip distance and speed a garmin gpsmap 76s handheld global position satellite (gps) unit and an externally mounted (roof) antenna (garmin ga 27c) were used. to ensure accurate positional readings the waas (wide angle augmentation system) capability of the gps unit was enabled which ensured a positional accuracy of <2 m. the position, distance and speed were recorded and stored automatically every second and downloaded via an interface cable to an ibm-compatible computer for further analysis using appropriate software (mapsource for windows version 6.3). statistical analysis data are expressed as mean (sd) unless otherwise stated. for skewed continuous data, the median (interquartile range) is reported. categorical data are expressed as a percentage. part 1 a general linear model (repeated-measures analysis of variance (anova)) was used to determine if the pedometer readings differed across walking speeds. to examine differences between pedometers for each of the walking speeds a one-way anova was used. post hoc analyses for both the repeated-measures anova and one-way anova were performed using the sidak correction for multiple comparisons to adjust the significance level. to evaluate the sources of variability in pedometer data, variance components in random effects models were estimated using restricted maximum likelihood methods. 23 pedometer output (steps) was the dependant variable for this analysis. variance components were estimated for pedometer variance (inter-instrument), trial variance (walking trial), and residual or error variance (intra-instrument). trial variance and residual variance were nested within intra-instrument variance. note that instrument refers to instruments of the same pedometer make. the variance components were also expressed as a percentage of the total variance. interinstrument variance represents true variation between instruments while intra-instrument variance represents trialto-trial variation within instruments. pedometer step-counting accuracy at a walking speed of 4.8 km.hr -1 (3.3 mets) was computed using the following formula, per cent error = (steps detected – actual steps)/ actual steps x 100), and expressed as an absolute and relative value. 21,37 a margin of error of 10% was used as a minimum standard for a promotional pedometer. 37 to categorise the direction of per cent error the following groupings were used; under-counting (<-10%), exact (±10%) and over-counting (>+10%). 37 part 2 because the kl data were highly skewed data, the kruskalwallis test was used to examine differences across pedometers, and if significant, dunn’s multiple comparison test was used to determine which differences were significant. a general linear model (univariate anova) was used to determine if the placement of the pedometers on the rig was a significant factor (row and column effects). because the kl data were highly skewed, all the pedometer data (steps.km -1 ) were ranked prior to running the statistical procedure. 29 significance for all inferential statistics was set at p < 0.05. data were analysed using spss for windows 13.0 (descriptive statistics, one-way anova, general linear models, variance components) and graphpad prism 4.03 (kruskal-wallis and dunn’s multiple comparison) pg67-78.indd 70 9/21/06 12:21:54 pm sajsm vol 18 no. 3 2006 71 results part 1 because one kl pedometer malfunctioned (battery failure), data are reported for 19 kl pedometers. for all other pedometers, data for 20 units per pedometer brand are reported. in contrast to the research-grade pedometers (figs 2 ac), the vt pedometer (fig. 2 d) was not consistent at lower walking speeds, but revealed far less variability than the kl pedometer (fig. 2 e). the amount of variability between kl monitors over all the walking speeds, but especially at the lower walking speeds, is visually evident (fig. 2 e). most of the pedometers (dw, nl, vt) tended to significantly undercount the actual number of steps at the two lower speeds to varying degrees (p < 0.02) (fig. 2, table i). a threshold is evident at 4.80 km.hr -1 ; above this threshold four of the pedometers table i. output for various pedometer brands during ambulatory and non-ambulatory activities treadmill walking (% of actual steps) 2 motor vehicle travel (steps.km -1 ) 3 pedometer brand 1 3.24 km.hr -1 4.02 km.hr -1 4.80 km.hr -1 5.64 km.hr -1 6.42 km.hr -1 distance: 62.9 km research-grade mti 94 (6) 4, 5 100 (2) 7 100 (3) 100 (3) 100 (6) 10.3 (2.3) 10 nl 51 (5) 4 94 (8) 100 (1) 101 (1) 100 (1) 2.6 (1.2) dw 41 (12) 4, 6 60 (15) 4, 8 98 (3) 4 100 (1) 100 (1) 4.9 (4.0) 11 promotional kl 68 (48) 79 (42) 84 (35) 9 95 (19) 95 (13) 2.2 (11.3) vt 64 (30) 4 85 (16) 4 102 (9) 101 (1) 100 (0.3) 0.7 (1.3) 1 mti = mti actigraph am-7164-2.2, nl = new lifestyles nl 2000, dw = yamax digiwalker sw-401, kl = kellogg’s special k step counter, vt = discovery vitality pedometer. data reported as 2 mean (sd) and 3 median (interquartile range). 4 significantly different from all other speeds for the same pedometer brand (p < 0.02), 5 mti > nl, dw, kl, vt (p < 0.03), 6 dw < kl (p < 0.02), 7 mti > kl (p < 0.04), 8 dw < mti, nl, vt (p < 0.003), 9 kl < mti, nl, vt (p < 0.04) , 10 mti > nl, dw, kl, vt (p < 0.05), 11 dw > vt (p < 0.01) fig. 2 a-e. pedometer performance during treadmill walking (mean ± sd). pg67-78.indd 71 9/21/06 12:21:55 pm 72 sajsm vol 18 no. 3 2006 (dw, mti, nl, vt) detected ~100% of the actual steps (fig. 2a-d, table i). from 3.24 to 4.80 km.hr -1 pedometer output for the same brand differed significantly across speeds (p < 0.05) (table i). below 5.64 km.hr -1 , pedometers brands differed significantly over the same speed (p < 0.05) but not above 5.64 km.hr -1 (table i). of particular note was the low inter-instrument variability of the mti and nl pedometers even at low walking speeds (fig. 2a-b). from the variance component analysis (table ii), it is evident that the research-grade pedometers (dw, mti, nl) have far less inter-instrument variability (0% to 1.3%) than the vt pedometer (10.4%) and especially the kl pedometer (60.4%). notably, the nl and mti pedometers exhibited ~0% inter-instrument variability and ~100% intra-instrument variability (table ii). by far the lowest amount of variance for most of the variance components was found in the mti pedometer (table ii). the walking trial and residual variation, nested within the intra-instrument variation, is also shown in table ii. of the research-grade pedometers (dw, mti, nl) the more sensitive mti monitor demonstrated lower variation across the trials and higher residual variation, which is in contrast to the dw and nl monitors which displayed greater specificity (higher variation across trials and lower residual variation). neither the kl nor the vt monitors quite reached the patterns of variability (walking speed, residual) of the research-grade pedometers (table ii). the absolute per cent error for the dw, kl, mti, nl and vt pedometers, at a treadmill walking speed of 4.8 km.hr -1 , was 2.6 (2.8)%, 25.6 (27.9)%, 2.1 (2.1)%, 0.7 (0.8)% and 5.3 (6.8)%, respectively. for a margin of error of ±10%, neither promotional pedometer achieved the accuracy levels of the research-grade pedometers (dw, mti, nl: 100% exact counting). only the vt pedometer achieved the required standards of a promotional pedometer (90% exact counts, 10% over-/undercounting). the kl pedometer exhibited poor accuracy levels (42.1% exact counts, 57.9% over-/ undercounting). part 2 there were no pedometer failures during this experiment. the distance, average speed and maximum speed for the motor vehicle trip was 62.9 km, 53.8 (29.1) km.hr -1 and 121 km.hr -1 , respectively. with regard to placement of pedometers on the rig, there was no row (f = 1.900, p = 0.200) or column (f = 0.195, p = 0.994) effect. in other words, whether the pedometer was mounted towards the back or front of the car, or mounted closer to the driver’s side or passenger’s side, did not have any effect on the pedometer output. the number of steps detected per kilometre differed significantly between some pedometers (table i). the mti detected significantly more steps than any of the other pedometers (p < 0.05) and the dw detected significantly more steps than the vt (p < 0.01).the variability (interquartile range) of the kl pedometer was noticeably greater than that of any of the other pedometers (fig. 3, table i). in contrast, the nl had the lowest variability, and barring two outliers, the vt demonstrated relatively low variability and seemed relatively resistant to registering non-ambulatory signals as ambulatory signals (fig. 3, table i). table ii. variance component analysis of the pedometer output obtained during treadmill walking pedometer brand 1 research-grade promotional sources of variance mti nl dw vt kl variance % 2 variance % variance % variance % variance % inter-instrument 0 0.0 1 0.2 11 1.3 53 10.4 759 60.4 intra-instrument 25 100 477 99.8 829 98.7 457 89.6 498 39.6 walking trial 6 25.7 460 96.2 765 91.0 263 51.6 107 8.5 residual 19 74.3 17 3.6 64 7.7 194 38.0 391 31.1 total 25 100 478 100 840 100 510 100 1257 100 1 mti = mti actigraph am-7164-2.2, nl = new lifestyles nl 2000, dw = yamax digiwalker sw-401, vt = discovery vitality pedometer, kl = kellogg’s special k step counter. 2 % = source of variance as a percentage of total variance. fig. 3. pedometer output in response to motor vehicle travel. mti = mti actigraph am-7164-2.2, dw = yamax digiwalker sw-401, nl = new lifestyles nl 2000, vt = discovery vitality pedometer, kl = kellogg’s special k step counter. pg67-78.indd 72 9/21/06 12:21:56 pm pg67-78.indd 73 9/21/06 12:21:56 pm 74 sajsm vol 18 no. 3 2006 discussion this study is novel in that it is the first study to report on the validity of pedometers, under controlled conditions, used in south african promotional programmes which emphasise physically active lifestyles. the principal findings of this study were firstly that the accuracy and quality of the kl pedometer was poor when compared with research-grade pedometers. secondly, the kl pedometer was the most variable in its response to non-ambulatory signals, so much so that it would not be possible to determine a correction factor. thirdly, neither the kl nor the vt pedometers quite reached a pattern of either high sensitivity (low walking trial variation, high residual variation) or high specificity (high walking trial variation, low residual variation) associated with researchgrade pedometers. fourthly, the vt pedometer performed within the margin of error expected of promotional pedometers during validity testing under controlled conditions, but the kl pedometer did not, and should therefore not be used in promotional programmes. the results from the present study are in agreement with the results from other pedometer calibration studies, specifically the greater sensitivity of accelerometer-type pedometers and the greater specificity of spring-type pedometers. 5,8,9,21,22 also in agreement with other work, the coiled spring dw pedometer was more variable than the piezo-electric mti 22 and nl 8 pedometers, especially at lower walking speeds. similarly, at lower walking speeds, hair-spring pedometers were more variable than the more accurate and durable coiled-spring pedometers. 5 finally, the results from this study concur that promotional pedometer output is particularly prone to inaccurate and erratic step counts. 10,14,37 studies have consistently demonstrated that for a level walking speed of 4.8 km.hr -1 , most good quality pedometers should measure close to 100% accuracy. 5,9,21 a margin of error from ± 1% 5,9,21,22 to less than ± 4% 25 has been found for research-grade pedometers during treadmill calibration at this speed. for verification tests using a fixed walking distance 32 or a fixed number of steps, 40 the margin of error has ranged from ± 3% to ± 5%. in a free-living environment, schneider et al. 31 suggest that in comparison to researchgrade pedometers, promotional pedometers should achieve at least a ± 10% margin of error. using the ± 10% margin of error for free-living environments, de cocker et al. 10 found that only 25.9% of the 973 promotional pedometers tested achieved this criterion. a recent validation study from north america evaluated promotional pedometers that were distributed in cereal boxes (kellogg’s special k). 37 this study employed a novel testing battery that comprised a 20-step test, a 4.8 km.hr -1 treadmill walking test, a motor vehicle test for susceptibility to non-ambulatory signals and a 24-hour free-living test. the pedometers used as gold standard were the yamax digiwalker and mti actigraph. a novel aspect of the study was that it provided quantitative performance criteria by which to judge whether a pedometer is suitable for promotional or research purposes. 37 tudor-locke et al. 37 found that 53% of the promotional pedometers did not pass the 20-step test (>5% margin of error) compared to the 100% success rate of the digiwalker. the mean absolute error for the treadmill walking test was 24.2 (33.9)% for the kellogg’s pedometer in contrast to the 3.9 (6.6)% of the digiwalker, 37 which is similar to the results from the present study. the promotional pedometer detected 5.7-fold more steps during the motor vehicle test than the digiwalker. 37 in contrast, the present study found the dw to accumulate 2.2-fold more steps during the motor vehicle test than the kl, although the kl variability was 2.8-fold greater than the dw, suggesting lower construction quality. the mean absolute per cent error under free-living conditions versus the actigraph was 44.9 (34.5)% for the special k pedometer and 19.5 (21.2)% for the digiwalker. 37 in the present study, the vt pedometer displayed lower absolute per cent error during treadmill walking and detected fewer steps during the motor vehicle ride, compared with the kl pedometer. however, it is important to note that although a pedometer can perform within the margin of error expected of promotional pedometers, it can demonstrate poor longevity, because of inferior construction methods and materials. standardised tests and standards for judging appropriate longevity have yet to be developed. the present study has also found the mti to be more susceptible to non-ambulatory signals compared with the dw. 22 the difference in absolute values between this study and others, 22,37 was likely the result of different mounting (human vs rig), vehicles (light motor vehicle vs recreational vehicle), vehicle speed and road surfaces. this study has also found that certain microprocessor algorithms, which exclude non-ambulatory signals, are less susceptible to nonambulatory signals. for instance, the nl and vt algorithms were better able to exclude non-ambulatory signals compared with the mti algorithm. it should be noted that low-quality pedometer construction would negate any algorithm written to exclude non-ambulatory signals. despite the mti’s higher false-positive count, the superior construction quality of the mti pedometer would result in low inter-instrument variance such that a correction factor could be calculated. 22 similarly, even in the absence of signal-filtering algorithms, highquality coiled-spring pedometers (dw) are less variant than low-quality hair-spring pedometers (kl) when responding to non-ambulatory signals, such that correction factors can be estimated. moreover, the lower variability of the vt pedometer compared with the dw pedometer would be expected to reverse over time because of the inherent frailty of the hair spring used in the vt pedometer construction. 24 this is despite the presence of a signal-filtering algorithm in the vt pedometer microprocessor. the type of spring mechanism of lever-arm-type pedometers is essential to the accuracy and longevity of these instruments. recent work has shown that hair-spring mechanisms fail substantially sooner than coil-spring mechanisms. 24 in a novel study, mckenzie et al. 24 tested one pg67-78.indd 74 9/21/06 12:21:56 pm pg67-78.indd 75 9/21/06 12:21:56 pm 76 sajsm vol 18 no. 3 2006 coil-spring pedometer (digiwalker sw-701, n = 10) and two hair-spring pedometers (sportline electronic 345, n = 10 and mcdonald’s stepometer, n = 10) to failure after repeated bouts of 100 000 steps on a customised bench-top orbital shaker at a simulated walking speed of ~4.82 km.hr -1 . failure was defined as ≥ 10% error for 50 steps at 4.82 km.hr-1 on a motorised treadmill. only new pedometers, that measured accurately to <10% prior to testing, were evaluated. the digiwalkers did not fail and the testing protocol was discontinued at 2.38 million steps because of high-step accumulation. the sportline and mcdonald’s pedometers failed at 710 000 steps and 250 000 steps, respectively. 24 assuming a sedentary individual accumulates 5 000 steps. day -1 , the sportline and mcdonald’s pedometers would measure accurately for 142 days and 50 days, respectively. for an active individual, accumulating 10 000 steps.day -1 , the sportline and mcdonald’s pedometers would measure accurately for 71 days and 25 days, respectively. because of the similarity between the mechanism and quality of construction of the kellogg’s and mcdonald’s pedometers, and the sportline and discovery vitality pedometers it would seem reasonable to expect similar failure rates for the promotional pedometers tested in the present study. these findings strongly suggest that prior to any promotional programme incorporating pedometers, longevity tests should be conducted either by the manufacturer or independent research institutions. users of the vt should be aware that the accreditation that appears on the packaging of the pedometer refers to the vitality programme and not to the quality of the pedometer. in other words, the pedometer has not been tested for validity or longevity by any accrediting agency of the discovery vitality programme (personal communication, laurence rau, vitality programme, discovery health, sa). similarly, there is no indication that the validity or longevity of the kl pedometer has been tested either by kellogg’s south africa or an independent institution. it is important to note that, unlike the dw and nl pedometers, neither the kl nor vt pedometers include in their instruction sheets or manuals any directions for simple tests that can be carried out by the user of the pedometer to determine if the pedometer is measuring accurately. for instance, in the dw instruction sheet, directions are provided for a simple 20-step test that the user can implement to determine if the pedometer is relatively accurate. it has been suggested that the accuracy of the vt pedometer is not particularly essential and that an expensive pedometer brand would limit people’s involvement in the vitality pedometer initiative. rather, the educational value of the vitality pedometer initiative as a whole is more important (personal communication, laurence rau, vitality programme, discovery health, sa). however, the reason pedometers are used is the direct, immediate and easily interpretable feedback they supply through the step count. 35 moreover, pedometers serve as a memory prompt and reminder with regard to maintaining physical activity behaviours. 38 villanova et al. 39 have noted that pedometers can provide a consistent, quantitative measure, a precise objective and can positively influence self-efficacy. consequently if the output is inaccurate and variable, the feedback is no longer reliable and cannot positively influence self-efficacy. the loss of positive feedback could theoretically adversely affect behaviour modification or adherence, defeating the rationale of the vitality ‘points’ system. with regard to cost, a viable alternative to the vt (~14 usd assuming an exchange rate of 7 zar to 1 usd) would be the dw pedometer which costs 20-30 usd. the australian 10 000 steps programme utilises the dw pedometer and discounts are given for bulk orders. 1 there are reports that a pedometer promotion run by coca cola in florida, usa had a pedometer return rate exceeding 60% because of product failure and inaccuracy (personal communication, michael cordier, national sales director, walk4life inc., usa). it is likely then that a significant number of promotional pedometers would probably either cease to be used or be returned because of inaccuracy or failure. the higher cost of the dw would be offset by fewer returns of new instruments and far greater durability of existing instruments. companies and organisations should investigate the most cost-effective strategy (cheap, lowquality pedometers with high failure rates vs. more expensive, high-quality pedometers with low failure rates) and whether they are committed to providing a pedometer brand which is more likely to favourably affect behaviour modification or adherence in programme participants. an alternative strategy would be to distribute better quality pedometers in a more selective manner to targeted groups or neighbourhoods. 14 kellogg’s and discovery health are not the only south african companies that have launched programmes promoting a physically active lifestyle by distributing pedometers. unilever launched the flora comrades step counter (fl) promotion which started in time for the 2005 flora comrades marathon. unfortunately, samples of these pedometers could not be obtained in time for inclusion in the study. however, a sample pedometer was recently obtained and upon inspection it was ascertained that the step-sensing mechanism consists of a lever arm, hair-spring mechanism, and a magnet on the end of the lever arm which activates a reed switch, completing the electric circuit and recording one step (fig. 1). furthermore, the fl pedometer does not contain an algorithm to filter out non-ambulatory signals. the control buttons are not covered so the unit could be inadvertently reset. on further inspection, the quality of manufacture of the fl pedometer is similar to that of the kl and vt pedometers. based on the spring-mechanism type and the quality of construction, it would seem reasonable to conclude that the fl pedometer would not have performed any better than the vt pedometer, and would most likely have performed similarly to the kl pedometer. there is no indication that the validity or longevity of the fl pedometer has been evaluated by unilever, nor are there any published data to that effect. this study does not address the effects of different pg67-78.indd 76 9/21/06 12:21:57 pm sajsm vol 18 no. 3 2006 77 levels of body weight and fat distribution, 8 pedometer tilt 8 and pedometer placement 5 on pedometer accuracy. further studies are required to test the promotional pedometers presented in this study under free-living conditions 10,31,37 and to assess the ‘longevity’ 24 of the units. are the results of this investigation generalisable to free-living conditions? le masurier et al. 21 have shown that if a pedometer performs poorly in the laboratory it will probably perform poorly in free-living conditions, suggesting that tests under controlled conditions are generalisable to free-living conditions. controlled testing conditions allow the investigation of intensityor speed-dependent responses of pedometers thus quantifying the sensitivity or specificity of the units. 21 in other words, are pedometers sensitive to a range of intensities (low-to-vigorous) or are pedometers specific to certain intensities (moderate-to-vigorous)? consequently, pedometers that demonstrate high sensitivity are susceptible to non-ambulatory signals 22 while pedometers that demonstrate high specificity will not detect steps accurately in populations that naturally ambulate at slower speeds, for example the elderly and those with a shuffling gait. 9,25 moreover, correction factors for pedometer output due to motor vehicle travel determined under controlled conditions 22 have been used in later free-living studies. 21 free-living conditions will however highlight problems relating to the inadvertent stopping or resetting of the unit because control buttons are not covered, 10 and the amount of misclassification of the physical activity status in relation to public health guidelines. 34 in conclusion, this investigation has shown that data from promotional pedometers must be treated with caution. in order for users to obtain reasonably valid and reliable readings from pedometers, companies or organisations initiating promotional programmes should consider the following (listed in order of preference, can include more than one recommendation as a verification procedure): • use a more expensive, but valid and durable pedometer, such as the yamax digiwalker 5,6,9,21,24,32 • require some form of quality control for validity and longevity from the manufacturer or an independent institution. for instance, the japanese industrial standard requires that pedometers achieve an error level of less than ±3% (3 steps out of 100 steps). 31 standardised tests, using a research-grade pedometer as a standard, could include performance under free-living conditions, 10 laboratory trials of level walking, 5,14 susceptibility to non-ambulatory signals (motor vehicle), 22,37 and longevity tests or ‘tests to failure’. 24 a comprehensive yet easily implemented protocol, which includes testing under controlled and free-living conditions, has recently been proposed. 37 • have a simple mechanical calibration device located at central points to be used prior to distributing the pedometers and at regular intervals during use. those pedometers performing outside certain limits should be replaced. • include self-calibration or self-verfication procedures in the instructions, which should be performed periodically to verify accuracy. those pedometers performing outside certain limits should be replaced. • a simple ‘shake test’ which requires the user to shake the pedometer up and down 100 times. 40 the reading must be within ± 5% (95 105 steps) • a 20-step walking test. 37,40 the reading must be within ± 5% (19 21 steps) • a 50-step 24 or 100-step 14,40 walk on a level, firm surface at a moderate pace (4.80 km.hr -1 , 3.3 mets, 50 m in 37.5 s or 100 m in 1 min 15 s) repeated twice and the average taken. this should be done with the pedometer on the dominant side of the body. at this speed research-grade pedometers should be ±1% accurate. 5,9,21 acceptable accuracy levels for promotional pedometers should be <10% (±4 steps of 50 steps or ±9 steps of 100 steps). 37 acknowledgements the research development and administration division of the university of limpopo (turfloop campus), and the institutional research development programme of the national research foundation supported this study. references 1. 10 000 steps programme (australia). available at: http://www.10000steps. org.au. accessed august 2006. 2. ainsworth be, haskell wl, whitt mc, et al. compendium of physical activities: an update of activity codes and met intensities. med sci sports exerc 2000; 32: s498-s504. 3. america on the move. available at: http://pedometer.americaonthemove. org/store/detail.asp?id=1. accessed august 2006. 4. anjos la, wahrlich v, vasconcellos mtl. distribution of pedometer count in a population-based sample of adults from niterio, rio de janerio, brazil. med sci sports exerc 2005; 37: s324. 5. bassett dr, ainsworth be, leggett sr, mathien ca, main ja, hunter dc, duncan ge. accuracy of five electronic pedometers for measuring distance walked. med sci sports exerc 1996; 28: 1071-77. 6. bassett dr, strath sj. use of pedometers to assess physical activity. in: welk gj, ed. physical activity assessments for health-related research. champaign, il: human kinetics, 2002: 163-77. 7. brage s, brage n, wedderkopp n, froberg k. reliability and validity of the computer science and applications accelerometer in a mechanical setting. meas phys educ exerc sci 2003; 7: 101-19. 8. crouter se, schneider pl, bassett dr. spring-levered versus piezo-electric pedometer accuracy in overweight and obese adults. med sci sports exerc 2005; 37: 1673-9. 9. crouter se, schneider pl, karabulut m, bassett dr. validity of 10 electronic pedometers for measuring steps, distance, and energy cost. med sci sports exerc 2003; 35: 1455-60. 10. de cocker k, cardon g, de bourdeaudhuij i. validity of the inexpensive stepping meter in counting steps in free living conditions: a pilot study. br j sports med 2006; 40: 714-6. 11. digital planet: discovery vitality pedometer (customer reviews). available at: http://www.digitalplanet.co.za/shop/product.asp?stockid=59886. accessed august 2006. 12. discovery health. available at: http://www.discovery.co.za. accessed august 2006. 13. doheny, k. pedometers tested as step to more exercise: mcdonald’s, others try a simple device to get people moving. available at: http://www. healthscout.com/news/407/515213/main.html. accessed august 2006. 14. gao y, boscolo m, krahling h, zhu w, lee m. step-count accuracy and instrument equivalence of mcdonalds’ stepometers. med sci sports exerc 2005; 37: s117. pg67-78.indd 77 9/21/06 12:21:57 pm 78 sajsm vol 18 no. 3 2006 15. james pt, leach r, kalamara e, shayeghi m. the worldwide obesity epidemic. obes res 2005; 9: 233s-88s. 16. jordan an, jurca gm, tudor-locke c, church ts, blair sn. pedometer indices for weekly physical activity recommendations in postmenopausal women. med sci sports exerc 2005; 37: 1627-32. 17. kearney pm, whelton m, reynolds k, muntner p, whelton pk, he j. global burden of hypertension: analysis of worldwide data. lancet 2005; 365: 217-23. 18. kellogg’s special k 10 000 step challenge (united kingdom). available at: http://www.kellogs.co.uk. accessed april 2006. 19. kellogg’s special k 2000 steps challenge (south africa). available at: http://specialk.experthealth.co.za/live/index.php. accessed august 2006. 20. kirk af, higgins la, hughes ar, fisher bm, mutrie n, hillis s, macintyre pd. a randomized, controlled trial to study the effect of exercise consultation on the promotion of physical activity in people with type 2 diabetes: a pilot study. diabet med 2001; 18: 877-82. 21. le masurier gc, lee sm, tudor-locke c. motion sensor accuracy under controlled and free-living conditions. med sci sports exerc 2004; 36: 90510. 22. le masurier gc, tudor-locke c. comparison of pedometer and accelerometer accuracy under controlled conditions. med sci sports exerc 2003; 35: 867-71. 23. matthews ce, ainsworth be, thompson rw, bassett dr. sources of variance in daily physical activity levels as measured by an accelerometer. med sci sports exerc 2002; 34: 1376-81. 24. mckenzie j, manning t, juergens ca, heil dp. a lab-test to evaluate pedometer longevity. med sci sports exerc 2005; 37: s117. 25. melanson el, knoll jr, bell ml, donahoo wt, hill jo, nysse lj, lanningham-foster l, peters jc, levine ja. commercially available pedometers: considerations for accurate step counting. prev med 2004; 39: 361-8. 26. metcalf bs, curnow js, evans c, voss ld, wilkin tj. technical reliability of the csa activity monitor: the earlybird study. med sci sports exerc 2002; 34: 1533-7. 27. moreau kl, degarmo r, langley j, mcmahon c, howley et, bassett dr, thompson dl. increasing daily walking lowers blood pressure in postmenopausal women. med sci sports exerc 2001; 33: 1825-31. 28. patterson re, frank ll, kristal ar, white e. a comprehensive examination of health conditions associated with obesity in older adults. am j prev med 2004; 27: 385-90. 29. pett ma. nonparametric statistics for health care research. thousand oaks, ca: sage publications, 1997. 30. puoane t, steyn k, bradshaw d, laubscher r, fourie j, lambert v, mbananga n. obesity in south africa: the south african demographic and health survey. obes res 2002; 10: 1038-48. 31. schneider pl, crouter se, bassett dr. pedometer measures of freeliving physical activity: comparison of 13 models. med sci sports exerc 2004; 36: 331-5. 32. schneider pl, crouter se, lukajic o, bassett dr. accuracy and reliability of 10 pedometers for measuring steps over a 400-m walk. med sci sports exerc 2003; 35: 1779-84. 33. the anatomy of a pedometer. available at: http://www.pedometers.com. accessed august 2006. 34. tudor-locke c, bassett dr. how many steps/day are enough? preliminary pedometer indices for public health. sports med 2004; 34: 1-8. 35. tudor-locke ce, myers am. methodological considerations for researchers and practitioners using pedometers to measure physical (ambulatory) activity. res q exerc sport 2001; 72: 1-12. 36. tudor-locke c, lind ka, reis jp, ainsworth be, macera ca. a preliminary evaluation of a pedometer-assessed physical activity self-monitoring survey. field methods 2004; 16: 422-38. 37. tudor-locke c, sisson sb, lee sm, craig cl, plotnikoff rc, bauman a. evaluation of quality of commercial pedometers. can j public health 2006; 97: s10-5. 38. tudor-locke ce, myers am, bell rc, harris sb, wilson rodger n. preliminary outcome evaluation of the first step program: a daily physical activity intervention for individuals with type 2 diabetes. patient educ couns 2002; 47: 23-8. 39. villanova n, pasqui f, burzacchini s, et al. a physical activity program to reinforce weight maintenance following a behavior program in overweight/ obese subjects. int j obes 2006; 30: 697-703. 40. vincent sd, sidman cl. determining measurement error in digital pedometers. meas phys educ exerc sci 2003; 7: 19-24. 41. walking the way to health initiative. available at: http://www.whi.org.uk. accessed august 2006. 42. wallis c. the obesity warlords. time 2004; 164: 46-51. 43. welk gj. physical activity assessments for health-related research. champaign, il: human kinetics, 2002. 44. welk gj. use of accelerometry-based activity monitors to assess physical activity. in: welk gj, ed. physical activity assessments for health-related research. champaign, il: human kinetics, 2002: 125-41. 45. wild s, roglic g, green a, sicree r, king h. global prevalence of diabetes. estimates for the year 2000 and projections for 2030. diabetes care 2004; 27: 1047-53. 46. yach d, mckee m, lopez ad, novotny t, for o, v. improving diet and physical activity: 12 lessons from controlling tobacco smoking. bmj 2005; 330: 898-900. 47. yusuf s, vaz m, pais p. tackling the challenge of cardiovascular disease burden in developing countries. am heart j 2004; 148: 1-4. pg67-78.indd 78 9/21/06 12:21:57 pm original research 74 sajsm vol 23 no. 3 2011 introduction body composition is a very important aspect of an athlete’s performance. according to the american dietetic association: ‘body weight can influence an athlete’s speed, endurance and power, whereas body composition can affect an athlete’s strength, agility and appearance.’ 1 determining optimal body weight and body composition for each individual according to age, sex, genetics and type of sport definitely has been shown to correlate well with race time and increased exercise performance. 2 assessment of body composition can be done via various ways. prediction equations with the use of a combination of anthropometric measurements and bioelectrical impedance analysis measurements have been compared and validated with the criterion methods. 3,4 nutrition is known to play a key role in exercise performance and endurance during extensive periods of exercise. in all sport, the main goal of nutritional strategies is to target and eliminate factors that impair exercise performance; these factors include fatigue, thirst, muscle glycogen depletion and gastro-intestinal disturbances. 5 nutrition is an important modifiable factor towards achieving the optimal body composition as well as providing fuel for increased levels of training. adequate energy should come from a wide variety of available foods which provide carbohydrate, protein, fat and micronutrients. 1 marginal vitamin and mineral deficiencies have been found to be present in some elite athletes, due to either an inadequate diet, reduced absorption by the gastro-intestinal tract, increased excretion in sweat, urine and faeces, increased turnover and the consequent biochemical adaptation to physical activity. 6 most athletes believe that supplements are necessary in order for an endurance athlete to reach their increased nutritional requirements. they also believe that supplements can promote changes due to activity, provide more consistent training sessions, improve recovery of muscle tissue between sessions, reduce the prevalence of injury or infection and enhance their competitive performance. 7 a triathlete has to ensure that his/her dietary intake, including the use of supplements, body composition and general immune health, are in harmony, not only for groups of athletes, but also specifically tailor made for the individual according to age, gender, ethnicity and genetics. in southern africa, to our knowledge, no study has investigated these aspects in triathletes competing in olympic and ironman distance events; therefore, the main aim of this study was to determine the body composition, dietary intake and supplement use amongst triathletes residing in the western cape region. a secondary aim was to determine and compare percentage body fat measured via anthropometry and multi-frequency bioelectrical impedance analysis. methods the study design was descriptive and cross-sectional with an analytical component. a convenient sample was selected from both the abstract objective. the aim of this study was to determine body composition, dietary intake and supplement use among olympic and ironman distance triathletes residing in the western cape. methods. a descriptive, analytical, cross-sectional study design was conducted in western cape province. twenty-six triathletes registered with triathlon south africa were included. percentage body fat was measured via multi-frequency bio-electrical impedance analysis and anthropometry. dietary intake and supplement use were measured with an estimated 3-day food record and questionnaire. results. the mean age of the men and women was 38±7 and 38±10 years respectively. the mean amount of training per week for men and women respectively was 15±4 and 15±5 hours. the percentage body fat (%bf) of men and women was 13±4% and 21±6%, respectively. the mean dietary macronutrient intake for men and women respectively was for total energy intake 14 535±4 510 kj and 9 004±2 369 kj, carbohydrate intake 5.3±1.9 g/kg and 3.5±1.0 g/kg, protein intake 2.0±0.5 g/kg and 1.2±0.2 g/kg and fat intake 35±10% and 30±6% of total energy intake. seventy-three per cent of the triathletes used over-thecounter dietary supplements. conclusion. percentage body fat of the men and women was at the upper end of the range associated with elite athletes. overall the athletes had a fairly good intake of macroand micronutrients. inadequate habitual carbohydrate intake was attenuated by the vast majority of the triathletes taking additional carbohydrate supplementation. various supplements were used widely among the athletes. sunita potgieter (master of nutrition)1 demetre labadarios (phd nutrition, mb chb)2 irene labuschagne (bsc dietetics)1 1 department of interdisciplinary health sciences, division human nutrition, stellenbosch university 2 population health, health systems and innovation, human sciences research council, cape town correspondence to: sunita potgieter (sunita@sun.ac.za) body composition, dietary intake and supplement use among triathletes residing in the western cape sajsm vol 23 no. 3 2011 75 2007 and 2008 western province triathlon (wpta) team. twentysix of these 91 (29% response rate) athletes were recruited by sending out an e-mail to all registered triathletes using the wpta database and the placement of an advertisement on the wpta website (http://www.wptriathlon.org). a reminder notice to participation was sent out midway during data collection to achieve maximum possible voluntary participation. the investigator also distributed pamphlets at most of the triathlon races during the 2007/2008 season. male or female triathletes aged 18 70 years, triathletes on the wpta team of 2007 and 2008 and who were training more than 10 hours per week (swimming, cycling and running) or triathletes who completed an ironman distance event 6 months prior to data collection and training more than 10 hours per week were included. the data collection phase was during the south african triathlon season from june 2007 to march 2008. the height and weight of the subjects were measured using a seca 767 column scale with height meter according to specifications from the literature. 8 the bicep, tricep, sub-scapular, supra-iliac, abdominal, chest, mid-axilla, thigh and calf skinfold thickness were measured with a dial gauge harpenden skinfold caliper. three skinfold measurements were taken at each individual site and the mean calculated for use in data analysis. all the anatomical sites were found as indicated for each individual skinfold thickness according to standard protocol. 8 body composition of the subjects was measured using a bodystat quadscan 4000sn (5 khz, 50 khz, 100 khz and 200 khz) isle of mann, 2000 multi-frequency bioelectrical impedance (mf-bia) meter. subjects were asked to adhere to the pretest conditions before bia measurement was taken. subjects were asked to remove all jewellery, watches and belts and instructed to remove the right shoe and sock as well as clear the hand and wrist area. subjects had fasted for 3 4 hours and abstained from exercising for 12 hours prior to the measurement. they were asked not to consume any alcohol or caffeine for 24 hours prior to the measurement. subjects were asked to lie in the supine position on a plinth for approximately 5 minutes before the measurements were taken. all the measurements were taken inside a building at normal room temperature and calibration and placement of the electrodes were as described by the manufacturer in the instruction manual. dietary intake was measured using a 3-day estimated food record. the food record also contained a section where the subjects were instructed to record daily supplement use. the subjects were asked to write down their food and beverage intake as accurately as possible and they signed a declaration stating that the information given was an accurate reflection of their dietary intake. they were instructed to record two weekdays and one weekend day on the food record. they were also asked to record their training on the days the food record was kept. an additional questionnaire was completed table 1. mean (sd) demographic and training characteristics of the triathletes by gender athletes characteristics male mean± sd (n = 13) female mean±sd (n = 13) t-test; p-value demographic characteristics age (years) 37.9±6.8 37.5±9.6 t= 0.1; p=0.050 anthropometric characteristics height (m) 1.8±0.1 1.7± 0.1 t= 3.9; p=0.001 body weight (kg) 78.9±12.9 63.9±10.3 t=3.3; p=0.003 body mass index (kg/m 2 ) 24.5±3.2 22.6±2.8 t=1.6; p=0.100 training characteristics (n=12)* total hours training per week 15.1±4.1 15.3±4.7 t=-0.1; p=0.900 swimming (hours per week) 3.5±2.1 4.2±2.5 t=-0.7; p=0.500 bicycling (hours per week) 6.5±2.1 6.4±2.5 t= 0.1; p=0.900 running (hours per week) 4.2±2.4 4.3±1.7 t=-0.1; p=0.900 gym/resistance training 0.9±1.1 0.5±0.9 t=1.1; p=0.300 (hours per week) swimming (km per week) 6.4± 2.6 10.2±5.9 t=2.1; p=0.010 bicycling (km per week) 173.8 ± 8.1 188.9 ±88.5 t=0.5; p=0.600 running (km per week) 39.6±17.9 41.5±16.6 t=-0.3; p=0.800 *one male subject neglected to complete the training characteristics questionnaire and did not respond to correspondence requesting its completion. fig. 1. mean (sd) of percentage body fat of triathletes by gender (male n=12, female n=9); prediction equations could not be determined from subjects due to skf measurements not obtained from subjects due to variation in skin compressibility and an increased muscle mass, making the skinfold thickness difficult and inaccurate to measure. 76 sajsm vol 23 no. 2 2011 by the subjects indicating general supplement use and reasons for taking the supplements as well as their general training regimen. all triathletes gave informed written consent and the study was approved by the health research ethics committee of stellenbosch university (reference number: n07/03/07). data analysis a registered dietitian edited and analysed the dietary intake data using the food finder iii computer software program (http://www. wamsys.co.za) and prediction equations were used to calculate percentage body fat from anthropometrical measurements. 9-12 statistical analysis data were entered into a spreadsheet on microsoft excel and transferred to statistica 8.0 for statistical analysis in consultation with a statistician. due to the descriptive and informative nature of the study, mostly descriptive statistics in the form of mean and standard deviation (sd) for nominal data and percentages of the total population for ordinal data were calculated to determine the central tendency. when repeated measures were compared with one another, repeated measures analysis of variance (anova) was used. the technique of bootstrapping was applied to estimate sample distributions for data from a bivariate normal distribution and the post hoc bonferroni test was applied to determine the significant differences between group means during analysis of variance (p<0.01). results twenty-six triathletes were included of whom 13 were male and 13 female. all the athletes were caucasian, except for one male participant who was of mixed ancestry. the demographic and training characteristics of the triathletes are summarised in table i. body composition the different %bf values for men and women respectively differed significantly irrespective of the method used and are portrayed against gender-specific reference values in fig. 1. when comparing the measurements, no significant difference was found with the men’s results when using analysis of variance and applying the bonferroni correction between the %bf from the mf-bia (12.6±4.2), %bf from the equation using 7 skf sites from evans et al. 2005 9 (12.6±4.4) (p=1.00), the %bf from the 4 skf site equation from jackson and pollock 1985 10 (12.1±4.9) (p=1.00), the %bf from the 3 skf site equation from jackson and pollock 1985 10 (12.5±4.9) (p=1.00) and the %bf from the body bite nutrition software program 11 (11.7± 5.2) (p=1.00). a significant difference was found between %bf measured from mf-bia and the 4 skf site equation from durnin and womersley 12 (17.5±5.5) (p<0.05) and the %bf from the 3 skf site equation from evans et al. 2005 9 (9.4±2.9) (p=0.01). the %bf from the women’s results showed no significant differences in the %bf from mf-bia (22.3±6.3) and the %bf from the 7 skf site equation from evans et al. 2005 9 (24.2±6.1) (p=1.00), the %bf from the 3 skf site equation from evans et al. 2005 9 (22.9±6.6) (p=1.00) and the %bf from the body bite nutrition software program 11 (23.4±9.0) (p=1.00). there was however a statistically significant difference between the %bf from mf-bia and the %bf from the 4 skf site equation from durnin and womersley 12 (30.0±7.2) (p<0.05) and the 4 skf site equation from jackson and pollock 1985 10 (32.40±8.95) (p<0.05). dietary intake and supplement use the total number of completed food records received was 18 out of a possible 26 food records (69% response rate), of which 9 were fig. 3. mean (sd) of micronutrient intake expressed as a percentage of the dietary reference intakes (dris) of the triathletes by gender. due to the limited reference values available for the interpretation of micronutrient intake in groups, the recommended daily allowance (rda) values were used. where available the adequate intake (ai) and the estimated average requirement (ear) values were used. fig. 2. mean (sd) of carbohydrate and protein intake of triathletes by gender (n=18)* (top) and mean (sd) of fat intake of triathletes by gender (n=18)* (bottom).*only 9 females and 9 males were included in the analysis of dietary intake because only 18 of the 26 subjects returned their completed food record. recommended protein intake is 1.2 1.7 g/kg body weight/day, recommended carbohydrate intake is 6 8 g/kg body weight/day, recommended fat intake (percentage of total energy) is 25%, sfa=10%, mufa=10%, pufa=10%, tfa <2% of te. sajsm vol 23 no. 3 2011 77 males and 9 females. the food records were handed out and the subjects were given a pre-paid postage envelope to mail it back to the researcher. however, not all the subjects sent the completed food records back or responded to follow-up reminders. dietary intake from diet does not include intake from additional supplements. this approach was adopted because it proved impractical to quantify the amounts consumed from the supplements used correctly. the total energy intake of the athletes for men and women respectively were 14 535±4 510 kj and 9 004±369 kj. upon calculating energy availability, the men and women had a mean energy availability of 162±58 kj/kg fat free mass (ffm) and 144±56 kj/kg/ ffm respectively. the results from the men and women differed significantly (t=3.3; p=0.05). the macronutrient intake is summarised in fig. 2. the intake of most of the micronutrients fell within 67 133% of the dietary reference intakes (dris). 13 the micronutrients with an intake below 67% of the dris for men included iodine 44% and fluoride 49% and for women, chloride 61%, iodine 31% and fluoride 52%. most of the micronutrients from dietary intake alone above 133% of the dri were still below the tolerable upper limit and not too excessive. the men’s intake of sodium, manganese and niacin was above the upper limit at 213%, 162% and 228% of the dri respectively. only the manganese intake of the women, 174% of the dris, fell above the upper limit. the micronutrients expressed as a percentage of the dris are shown in fig. 3. provision has been made in the food finder database for 145 nutrients. information is not yet available on all the nutrients. there may be a significant number of missing values for nutrients and micronutrient intake should be interpreted keeping in mind the limitations of the database. a separate questionnaire was given to the subjects to report supplement and reasons for supplement use (n=26). seventy-three per cent (n=19) of the triathletes used over-the-counter dietary supplements (chi-square; p=1.0). supplement use is summarised in table ii. the athletes took supplements daily (35%) (n=9) several times a week (19%) (n=5) or during specific times, i.e. increased training or racing on consecutive weekends (19%) (n=5). reasons why the triathletes were taking the supplements are summarised in fig. 4. discussion this is the first study of its type in south africa using triathletes as study population. the findings of this study contribute to the body of current knowledge on endurance athletes like runners and cyclists, table ii. prevalence of supplement use among the triathletes supplement category supplements percentage triathletes (n=26) chi-square; p-value increased muscle growth and repair protein 100% (n=26) no value amino acids 27% (n=7) p=0.7 increased energy supply carbohydrate 81% (n=21) p=0.1 creatine 12% (n=3) p=0.5 increased immune function antioxidants 54% (n=14) p=1.0 glutamine 4% (n=1) p=0.3 increased joint health glucosamine sulphate 4% (n=1) p=0.3 cns stimulants caffeine 4% (n=1) p=0.3 fat reduction carnitine 4% (n=1) p=0.3 electrolytes salt tablets 19% (n=5) p=0.6 general health multivitamin and mineral 81% (n=21) p=0.6 vitamin b12 65% (n=17) p=0.7 single minerals 58% (n=15) p=0.7 iron 4% (n=1) p=0.3 calcium 4% (n=1) p=0.3 magnesium 27% (n=7) p=0.2 essential fatty acids 8% (n=2) p=1.0 herbal supplements* 42% (n=11) p=0.7 probiotics 4% (n = 1) p=0.3 *herbal supplements include ginseng, echinacea, inositol, guarana and green tea extract. fig. 4. reasons given by triathletes for taking supplements. 78 sajsm vol 23 no. 3 2011 but gives new insight on the nutritional status of triathletes. the key findings of the present study were that percentage body fat calculated from skinfold prediction equations generally correlated well with percentage body fat measured with mf-bia. the percentage body fat of the men and women was at the upper end of the range associated with elite athletes and related more to the percentage body fat of amateur athletes. the athletes had a good dietary intake of micronutrients. the triathletes consumed less than optimal amounts of dietary carbohydrate and supplements were used widely, including carbohydrate and protein supplementation even though dietary protein intake was adequate for both men and women. fat intake was higher than the recommendation in both groups. body composition percentage body fat calculated from skinfold prediction equations generally correlated well with percentage body fat measured with mf-bia. significant associations in both and men women were obtained between percentage body fat calculated from skinfold measurements and mf-bia. the findings of this study support those described by ostojic et al. 2005, who found that %bf from skinfold measurements and %bf from bia correlated well in male athletes. 14 dietary intake and supplement use an athlete’s habitual dietary intake is very important to ensure that he or she meets the increased energy requirements of triathlon. the body’s ability to adapt to the stress of intense daily exercise depends on the adequacy of the athlete’s diet. 15 the world health organization defines energy requirement as ‘the level of energy intake from food that will balance energy expenditure when the individual has a body size and composition, and level of physical activity, consistent with long-term good health; and that will allow for the maintenance of economically necessary and socially desirable physical activity.’ 16 the international olympic committee (ioc) recommends in its position statement on nutrition for athletes that energy availability, rather than total energy requirements, should be calculated (135 kj/kg/ ffm). 17 they concluded that if energy availability is below the recommendation, that there can be changes in metabolic and hormonal function, which can affect sport performance and health in general. this is especially true for females where a reduced energy availability can influence reproductive health. 17 the male and female athletes in the present study had a higher than recommended energy availability. the women also had a higher than anticipated percentage body fat and a normal body mass index (bmi) and none of the women reported weight loss in the preceding months, which indicates that the women are indeed in energy balance. the majority of the women also reported having regular monthly menses (77%). the women’s results for total energy intake also coincided with findings of worme et al. (1990), 18 who found the mean total energy intake of 21 recreational female triathletes to be 9 058 kj. they also reported the mean total energy intake for 50 male triathletes to be 11 591 kj. 18 the evidence on importance of adequate carbohydrate intake for athletes has been described and concludes that muscle glycogen is the most important energy substrate during endurance exercise and a decreased intake can lead to less than optimal training, recovery post training and performance. a sub-optimal carbohydrate intake can also lead to feeling fatigued, often not being able to finish training sessions due to a feeling of hitting the wall, lack of energy, heavy legs, slow rate of recovery, and loss of concentration, dizziness, irritability and fainting. 19 the carbohydrate intake of 21 female and 50 male recreational triathletes as reported by worme et al. was 5.1 g/kg body weight and 4.9 g/kg body weight for men and women respectively. 18 nogueira et al. (2004) also described the cho intake of endurance athletes as 4.5 11.3 g/kg bw for males and 4.4 7.2 g/kg bw for females. 20 frentsos et al. (1997) also reported that 6 elite triathletes only had a carbohydrate intake of 4 g/kg bw before intervention. 21 the male triathletes in the present study are meeting carbohydrate requirements and the female athletes are not meeting the recommended requirements, with an intake of 5.26 g/kg bw for men and 3.54 g/kg bw for women, respectively. literature suggests that endurance athletes should have a carbohydrate intake of 5 7 g/ kg bw or 6 8 g/kg bw. 17,22 however, the practical implementation of this recommendation should be taken into consideration, especially with the female athletes in the present study who have a higher than recommended percentage body fat and adequate energy availability. most (81%) of the triathletes in our study group also consumed some form of a cho supplementation and listed an increase in energy supply as one of the main reasons for taking supplements. this could make up for the inadequate dietary cho intake; however quantifying the amount of cho supplements taken in future studies is recommended. the present study indicated that the dietary intake of protein for male triathletes was 1.95 g/kg bw and for female triathletes 1.20 g/ kg bw. worme et al. reported the habitual protein intake of both male and female triathletes to be 1.4 g/kg body weight per day. 18 nogueira et al. reported a habitual dietary protein intake for endurance athletes as 1.2 2.0 g/kg body weight. 20 protein in combination with carbohydrate in an endurance athlete’s diet is especially important for recovery after training sessions and when carbohydrate intake after training is limited, such as a low appetite or short recovery periods. it is required to cover the increased losses of amino acids oxidised during exercise and to provide extra raw material to replace exercise-induced muscle damage. 23 the requirements for protein in endurance athletes are higher than those of sedentary peers (1.2 1.7 g/kg body weight v. 0.8 1.0 g/kg body weight) 22 due to the fact that some amino acids (including the branched chain amino acids) are oxidised in larger amounts during exercise. 23 all of the athletes in the present study also reported taking some form of protein supplementation, which is unnecessary as well as energy dense and can lead to weight gain. fat is a very important macronutrient for endurance athletes as it provides the training diet with essential fatty acids (efas) and fat-soluble vitamins. the male (35±10%) and female (30± 6.0%) triathletes in this study had a very high fat intake compared with the requirements of 25% of total energy intake. 1 the distribution of the different types of fatty acids in this group was not according to prudent dietary guidelines and recommendations to increase sources of polyand monounsaturated fatty acids while reducing saturated and total fat intake in the diet should be made. there are certain vitamin and mineral requirements that are increased during physical activity and according to the ioc, adequate intakes of iron, copper, manganese, magnesium, selenium, sodium, zinc, vitamin a, e, c, b6 and b12 necessary for optimal health and performance. 17 it should be noted that supplementation of micronutrients are not required and that it only affects performance if the athlete has a deficiency of the nutrient. 7 in the present study, the athletes had a good intake of micronutrients and most values fell within 67 133% of the dris. micronutrients of which the intake was below 67%, such as iodine and fluoride, are not a concern as the athletes will take this in via iodated salt and toothpaste, which is not accounted for in the dietary analysis software programme. the micronutrient intake that fell above the 133% of the dri is still below the tolerable upper level and not a concern. in a study by striegel et al. (2006) 24 on master’s athletes, 61% of athletes were consuming sajsm vol 23 no. 3 2011 79 dietary supplements as compared with our study group in which 73% took dietary supplements. the majority of the triathletes took a form of multivitamin supplementation which shows that they feel their diet is not providing adequate nutrition. they also indicated an inadequate diet or nutrient replacement as being a popular reason for using supplements. other popular reasons for taking supplements included to provide an increased energy supply, optimise recovery, increase lean body mass and to support the immune function. according to the ioc, an athlete can take a multivitamin-mineral preparation to support a low energy or restricted diet, although in our study population this does not seem necessary. 17 supplement use in athletes should be carefully monitored. contamination of supplements and ingredients in supplements with no beneficial effect can harm athletes and the ioc has clear guidelines as to which supplements are recommended and which are banned. 25 conclusion in the present study we found that two of the popular field methods for determining percentage body fat in athletes do correlate well when the appropriate equations are used. our dietary intake findings were that the triathletes had a high energy availability and consumed enough dietary carbohydrate and protein. the fat intake was higher than the recommendation in both groups. supplements were also widely used among the athletes. recommendations for future studies would be to include a larger study population as it would be beneficial to have a large enough study population to divide the group into subgroups of elite and amateur athletes. future studies can also go into more depth regarding quantifying the supplements used by the athletes and adding this to determine their habitual dietary intake. timing of nutrient intake in relation to training would also provide valuable information in future studies. references 1. american dietetic association. position of the american dietetic association dietitians of canada and the american college of sport: nutrition and athletic performance. j am diet assoc 2009;109:509-527. 2. knechtle b, wirth a, baumann b, knechtle p, rosemann t and senn o. differential correlations between anthropometry, training volume, and performance in male and female ironman athletes. j strength cond res 2010;24(10):2785-2793. 3. garcia al, wagner k, hothorn t, koebnick c, joachim h, zunfit f, trippo u. improved prediction of body fat by measuring skinfold thickness, circumferences, and bone breadths. obesity research 2005;13(3):626-634. 4. kyle ug, bosaeus i, de lorenzo ad, deurenberg p, elia m, gomez jm, et al. bioelectrical impedance analysis – part 1: review of principles and methods. clin nutr. 2004;23:1226-1243. 5. bentley d, cox g, green d, laursen p. maximising performance in triathlon: applied physiological and nutritional aspects of elite and non-elite competitions. j sci med sport 2008;11(4):407-417. 6. knez w, peake j. the prevalence of vitamin supplementation in ultraendurance triathletes. int j sport nutr ex met 2010;20(6):507-514. 7. maughan rj, depiesse f, geyer h. the use of dietary supplements by athletes. j sport sci 2007;25(si):s103-s113. 8. lee rd, nieman dc. nutritional assessment. 3rd ed. 2003:63-215. 9. evans em, rowe da, misic mm, et al. skinfold prediction equation for athletes developed using a four-component model. med sci sports exerc 2005;2006-2011. 10. jackson as, pollock m. practical assessment of body composition. phys sport med 1985;13:76-90. 11. body byte® pro v3.20. body and nutrition manager software program. 12. durnin jvga, womersley j. body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16-72 years. br j nutr 1974;34:77-97. 13. dietary reference intakes. nutrition information centre of the university of stellenbosch. 2003. adapted from: dietary reference intakes. the essential guide to nutrient requirements. 2001. institute of medicine. washington: the national academic press. 14. ostojic sm. estimation of body fat in athletes: skinfolds vs. bioelectrical impedance. j sports med phys fitness 2005;46(3):442-446. 15. laursen pb, rhodes ec. factors affecting performance in an ultra-endurance triathlon. sports med 2001;31(3):195-209. 16. world health organization website [online] [access 2008, june]; available: http://www.who.int/bmi/index 17. burke lm. the ioc consensus on sport nutrition 2003: new guidelines for nutrition for athletes. 2003;13(4):549-52. 18. worme jd, doubt tj, singh a, et al. dietary patterns, gastrointestinal complaints, and nutrition knowledge of recreational triathletes. am j clin nutr 1990;51:690-697. 19. ivy jl. role of carbohydrate in physical activity. clin sports med. 1999;18(3):469-484 20. noguiera ja, da costa th. nutrient intake and eating habits of triathletes on a brazilian diet. int j sport nutr exerc metab 2004;14(6):684-697. 21. frentsos ja, baer jt. increased energy and nutrient intake during training and competition improves elite triathlete’s endurance performance. int j sport nutr 1997;7:61-71. 22. hawley ja, burke lm. peak performance: training and nutritional strategies for sport. sydney: allen and unwin, 1998. 23. tipton kd, wolfe rr. protein and amino acids for athletes. j sport sci 2004;22(1):65-79. 24. striegel h, simon p, wurster c. the use of nutritional supplements among master athletes. int j sports med 2006;27:236-241. 25. the world anti-doping code. the 2010 prohibited list international standard. 2010 [online] [access 2010, september]; available:http://www.wadaama.org/documents/world_anti-doping_program/wadp-prohibited-list/ wada_prohibited_list_2010_en.pdf. original research 84 sajsm vol 23 no. 3 2011 introduction arthritis is one of the main causes of human disability, limiting everyday activities such as dressing, climbing stairs, getting in and out of bed, or walking. 1 rheumatoid arthritis (ra) is the most common type of chronic inflammatory arthritis. 2 ra is characterised by inflammation of the synovial lining of the joints, which ultimately results in cartilage and bone destruction. 3 ra can affect any joint, large or small; however, the small joints are the most commonly affected. since ra is a systemic disease, other parts of the body may be involved in the inflammatory process. 1 although there is no cure for ra the condition can be managed with various strategies. 4 the use of exercise in the treatment of patients with ra has been widely debated in the past. in the late 1800s, the concept of total bed-rest became the standard care. it was not until 1948 when the undesirable effects of prolonged bed-rest were described, that exercise resumed its role in arthritis therapy and rehabilitation. 5 over the past decades there has been growing evidence of the health benefits of physical activity for patients with ra. 6 in ra various factors may lead to a decline in functional ability. apart from the direct consequences of the disease on the function of joints and muscles, physical inactivity contributes further to stiffness of the joints, muscle weakness and cardiorespiratory deconditioning. 7 research shows that patients with ra are in general less fit and more at risk of comorbidities when compared with healthy, age-matched controls. 8-10 the primary goal of exercise therapy for ra is to improve joint mobility, muscle strength and aerobic and functional capacity. 11 however, there is a debate as to what type of exercise would be the best for ra patients. 5 hydrotherapy has been shown to increase muscle strength, increase joint range of motion, improve aerobic capacity, reduce pain and improve function. 12 the buoyancy of water and the ability to control its temperature make it favourable for patients with muscular and joint disease. although most research conducted suggests that exercises in water are beneficial for ra patients, numerous problems exist with the prescription of water therapy programmes. for example, proper water facilities for exercise therapy are not always available. heated pools designed for exercise therapy are expensive and maintenance is also time consuming and costly. home exercise programmes, usually consisting of land-based exercise, are often prescribed for ra patients. land-based exercises, specifically weight-bearing exercise, also have the advantage of strengthening the connective tissue surrounding the joints and stimulating bone formation. 5 these qualities are desirable because of the well-known complications of accelerated generalised osteoporosis induced by active inflammation, immobility and medication (cortisone) in ra. 11 in the past much research on ra patients and exercise has focused on water-based exercises. although recently more research has started focusing on land-based exercises, several questions remain unanswered. 13 the efficacy of land-based exercise intervention with respect to pain, disease activity, functional ability, quality of life and structural damage remain unclear. 14 therefore, the aim of this study was to determine the outcome of exercise therapy, specifically comparing the effects of a land-based exercise programme with that of a water-based exercise programme in ra sufferers. abstract objective. to compare the effects of a 3-month landand waterbased exercise programme among rheumatoid arthritis (ra) sufferers. methods. patients with ra functional class i and ii (n=10) were randomly assigned to a land-based exercise group (group l) (n=4), water-based exercise group (group w) (n=4) or a control group (group c) (n=2). testing parameters included swollen joint count (sjc), tender joint count (tjc), erythrocyte sedimentation rate (esr), haemoglobin (hb), 50-ft (15.2-m) walk test, grip strength, isokinetic strength of knee extensors and flexors, knee range of motion (rom) and aerobic capacity. results. there were individual improvements in most of the physical status parameters tested for the experimental groups (land-based exercise group and water-based exercise group) while the general trend for the control group was that of deterioration. appropriate land-based exercises did not appear to aggravate disease activity. however, the water-based exercise programme was superior in controlling the disease activity with regards to the tender and swollen joint counts. conclusion. both exercise interventions appeared to be beneficial in the treatment of ra. further research is required comparing various modes of exercises for the treatment of ra, using larger samples and evaluating the long-term effects. kim nolte (dphil)1 dina c janse van rensburg (mb chb, mmed, msc sports medicine)2 pieter e krüger (dphil)1 1 department of biokinetics, sport and leisure sciences, university of pretoria, south africa 2 section sports medicine, university of pretoria, south africa correspondence to: kim nolte (kim.nolte@up.ac.za) landand water-based exercises in rheumatoid arthritis patients: a series of case reports sajsm vol 23 no. 3 2011 85 methods ethical clearance for this study was obtained from the faculty of humanities research proposal and ethics committee of the university of pretoria, south africa. all subjects were required voluntarily to read and sign an informed consent. subjects patients with classical or definite ra and mild to moderate disease activity (american college of rheumatology functional class i and ii), were randomly assigned to the land-based exercise group (group l), water-based exercise group (group w) or non-exercise group (group c). all patients were on stable medication. exclusion criteria included the presence of unstable cardiopulmonary disease, acute joint symptoms and current participation in a physical fitness programme or organised sports activity. exercise intervention subjects in the exercise groups were required to exercise 2 3 times per week for a 3-month period. those in the control group were instructed to continue with their normal sedentary lifestyle. group l and w attended their rehabilitation sessions at the university of pretoria rehabilitation gymnasium and hydrotherapy pool, respectively. the same biokineticist instructed both groups throughout their participation in the study. both the landand water-based exercise programmes were aimed at improving range-of-motion, muscle strength and cardiorespiratory endurance. the exercise intervention consisted of warm-up exercises, strengthening exercises, aerobic exercises and cool-down exercises with stretches. initially, the duration of the warm-up and strengthening phases was longer in order to build muscle strength. aerobic exercise time was gradually increased as cardiorespiratory fitness improved. the total duration of an exercise session in each of the 2 programmes was approximately 45 minutes each. assessments each patient was assessed 3 times throughout the study to track progress: before the exercise intervention, 5 6 weeks into the exercise intervention and at the end of the exercise intervention (3 months). the results of only the preand post-exercise assessments are reported. table i. gender, age and anthropometry subject gender age (years) stature (cm) body mass (kg) w1 female 66 159.1 92.0 w2 female 64 161.7 85.8 w3 female 52 161.4 71.0 w4 female 52 162.7 68.1 l1 male 60 199.6 105.4 l2 female 41 168.8 52.1 l3 female 57 170.4 97.3 l4 female 53 169.2 60.2 c1 female 43 167.4 54.6 c2 female 53 170.0 60.0 average 54.1 ± 8.1 169.0 ± 11.5 74.7 ± 9.1 w = water-based exercise programme; l = land-based exercise programme; c = control. table ii. total tender and swollen joint counts total tender joint count total swollen joint count subject pre post difference clinically relevant pre post difference clinically relevant w1 6 2 -4 yes 5 1 -4 yes w2 24 10 -14 yes 14 10 -4 yes w3 11 8 -3 no 12 8 -4 yes w4 10 6 -4 yes 4 6 2 no l1 11 15 4 yes 13 13 0 no l2 9 6 -3 no 9 8 -1 no l3 10 10 0 no 10 9 -1 no l4 13 10 -3 no 13 11 -2 no c1 8 8 0 no 10 10 0 no c2 19 19 0 no 16 16 0 no w = water-based exercise programme; l = land-based exercise programme; c = control. 86 sajsm vol 23 no. 3 2011 clinical assessment a medical specialist rheumatologist performed all clinical assessments. joints were examined for soft-tissue swelling and tenderness and pain during motion, using the american college of rheumatology, rheumatoid arthritis clinical response criteria. 15 haematological assessment blood samples were drawn and standard laboratory procedures were used to estimate erythrocyte sedimentation rate (esr) (modified westergren, mm/h) and haemoglobin (hb)(gm/dl). 16 physical status assessment the following functional assessments were performed: • a 50-ft (15.2m) walk test. 3 • manual grip strength was measured with a sphygmomanometer cuff rolled up two turns and inflated to 20 mmhg. • the strength of the knee extensors and flexors was tested on an isokinetic dynamometer (cybex norm 7000). a speed of 60°/second was used, 3 trial repetitions and 5 test repetitions were performed. • knee range of motion was measured using a standard goniometer. • bicycle ergometer testing was performed to determine aerobic capacity. the astrand-rhyming protocol to obtain data for calculating the estimated vo2max of each subject was used. 3 the test was started with an initial load of 25 watts (w) at a cadence of 60 70 revolutions per minute with an increment increase of 25 w until exhaustion. statistical analyses computations to determine standard descriptive statistics (mean and standard deviation) for age, stature and body mass of participants were performed using the statistical package for social sciences (spss), microsoft windows release 9.0 (1999). due to the small sample the raw data and the difference between the pre and post data are presented for each subject. these changes are interpreted in the context of clinically meaningful results for each variable. results ten patients (9 females, 1 male) with classic or definite ra volunteered for the study. the mean (±sd) age, stature, and body mass of the subjects was 54.1±8.1 years, 169.0±11.5 cm and 74.7± 9.1 kg, respectively. subjects were randomly assigned to group l, w or c (table i). clinical and haematological assessment results an increase or decrease of 4 joints may be considered to be clinically significant or a meaningful change for the joint counts. the total tjc decreased in all the subjects in group w. the decreases were all deemed to be clinically significant. in group l, the total tjc decreased in two of the subjects, remained unchanged in one and increased in another. none of the changes was deemed to be clinically relevant except for the subject whose total tjc increased. there was no change in the total tjc of the subjects in group c. the total sjc decreased in a clinically meaningful way in 3 of the 4 subjects in group w. one subject’s sjc increased in group w; however, the increase was not deemed to be clinically relevant. there was a nonclinically relevant decrease in 3 of the subjects’ sjc in group l and 1 subject’s sjc was unchanged. there was no change in the sjc of the subjects in group c (table ii). the haemoglobin values remained unchanged in all 3 groups. there were changes in the esr in the groups; however, no specific trends were identified and values generally fell within normal clinical reference ranges (table iii). physical status assessments results various aspects of physical conditioning are shown in tables iv and v. there was an improvement in group w and group l’s physical condition as determined by the 50-ft (15.2-m) walk and aerobic capacity test for all subjects, while there were no improvements noted in group c. in general, for other variables there were trends of improvement for group w and group l but not group c. discussion there is a growing interest among health professionals in improving the care of patients afflicted with chronic disabling diseases such as ra. in particular there is interest on the effects of exercise training programmes on the measurements of improvement in joint function, mobility, strength, endurance and cardiovascular fitness. 17 one of the aims of this study was to determine whether exercise therapy is beneficial for ra patients. the positive changes produced by the landand water-based exercise programmes are evident in the results as far as the disease (total and swollen joint count) and physical status of the subjects were concerned. the exercise therapies appeared to assist in the control of the disease activity as both the tjc and sjc were reduced in most of the subjects in the experimental groups, but not in the control group. there was a decrease in 6 of the subject’s joint counts (tjc and sjc) in the experimental groups, 3 of which were clinically significant decreases. no specific trends could be identified in the esr. however, in the experimental groups, 3 subjects’ esr increased, 1 in group w and 2 in group l. despite the increases, values fell within acceptable ranges with the exception of 1 subject in group l. however, this subject’s esr was on the border of the acceptable range even before the start of the intervention. in the control group 1 subject’s esr remained unchanged and the other subjects decreased. it is important to note that esr can be influenced by factors other than ra, such as anaemia, pregnancy and age. therefore it may be useful to conduct other haematological assessments in addition to esr such as c-reactive protein (crp) to get a true reflection of the inflammatory status of the disease. table iii. erythrocyte sedimentation rate erythrocyte sedimentation rate (mm.h -1 ) subject pre post difference within clinical reference range w1 10 20 10 yes (pre and post) w2 20 10 -10 yes (pre and post) w3 50 26 -24 no (pre) yes (post) w4 2 2 0 yes (pre and post) l1 7 10 3 yes (pre and post) l2 9 7 -2 yes (pre and post) l3 30 42 12 yes (pre) no (post) l4 13 7 -6 yes (pre and post) c1 18 18 0 yes (pre and post) c2 30 14 -16 yes (pre and post) w = water-based exercise programme; l = land-based exercise programme; c = control. sajsm vol 23 no. 3 2011 87 most of the physical status parameters assessed were positively influenced by both exercise therapies. the improvements in aerobic capacity are especially noteworthy due to the fact that in the past exercise therapy in ra primarily aimed at maintaining joint mobility and muscle strength. 14 however, because of the increased risk of cardiovascular events such as atherosclerosis of the coronary artery, aerobic training and fitness should be given the sufficient attention it deserves with regards to exercise programming. other compelling evidence advocating the importance of aerobic exercises for ra sufferers was that of a systematic review and meta-analysis by baillet and colleagues. 14 the study found that aerobic exercises improve some of the most important ra patient outcomes: function, quality of life and pain. moreover, it appears that aerobic exercise decreases radiological damage and pain. 14 vo2max or vo2peak is considered a measure for aerobic fitness. in this study both the landand waterbased exercise groups similarly improved their relative and absolute vo2max as well as their 50-ft walk test time (table iv). another study has shown that vo2max of subjects improved by 12% after following a 12-week endurance training programme. 18 in contrast, in the nonexercise group there were no improvements in aerobic capacity parameters tested. in fact, one of the subjects showed deterioration. it is important to note that even small changes can be expected to have a detrimental impact on a ra patient, especially if one considers that the decline took place over a short period of time. due to the involvement of the joints of the hand and wrist, ra can influence grip strength. therefore grip strength is considered an important measurement of a ra patient’s functional status. poor grip strength can affect activities of daily living such as the ability to open and close small buttons, to write and to perform any function related to work or housework. 19 the exercise therapies appeared to have a positive effect on grip strength in comparison to the control group. in the experimental groups, 7 of the subjects’ left grip strength improved and 4 of the subjects’ right grip strength improved. in the control group there was a decrease in both left and right grip strength for both subjects except for 1 subject whose right grip strength minimally improved (table v). impaired muscle function is a common consequence in patients with ra. 8 it is important to maintain normal muscle strength, not only to maintain physical function, but also to stabilise the joints and prevent joint angulation and later osteoarthrosis. 16 in general, table v. physical parameters subject grip (mmhg) isokinetic flexion (nm/kg) isokinetic extension (nm/kg) range of motion (°) flexion range of motion (°) extension l r l r l r l r l r w1 138 162 29.3 21.7 64.1 64.1 84 79 0 0 w2 100 103 8.2 9.4 40.0 49.4 105 115 0 0 w3 80 102 65.0 66.2 125.4 140.8 130 125 0 0 w4 108 120 50.0 39.7 70.6 66.2 121 121 0 0 l1 265 265 83.8 64.8 168.6 140.0 120 125 9 14 l2 60 62 84.1 98.1 203.8 238.0 125 124 0 0 l3 81 85 47.4 48.5 101.0 89.7 112 115 0 0 l4 91 90 68.3 85.0 116.7 141.7 130 115 0 0 c1 59 41 92.6 85.2 175.9 188.9 131 130 0 0 c2 44 40 55.0 65.0 128.3 151.7 122 125 0 0 w = water-based exercise programme; l = land-based exercise programme; c = control. table iv. 50-ft (15.2m) walk test and relative maximal oxygen consumption 50-ft walk test (s) maximal oxygen consumption (ml.kg -1 .min -1 ) subject pre post difference pre post difference w1 10.1 9.1 -1.0 11.6 19.7 8.1 w2 10.5 7.5 -3.0 20.7 23.9 3.2 w3 11.4 9.7 -1.7 21.9 35.9 14 w4 9.6 8.0 -1.6 36.4 38.6 2.2 l1 8.0 6.8 -1.2 17.2 22.3 5.1 l2 8.3 6.9 -1.4 37.8 41.0 3.2 l3 9.2 7.8 -1.4 15.8 23.2 7.4 l4 8.0 6.9 -1.1 45.2 48.8 3.6 c1 7.5 7.3 -0.2 38.1 30.6 -7.5 c2 9.4 9.5 0.1 32.0 32.1 0.1 w = water-based exercise programme; l = land-based exercise programme; c = control. 88 sajsm vol 23 no. 3 2011 there was an increase in knee extensor and flexor strength in the experimental groups and a deterioration in the control group. there appeared to be a more consistent improvement in the knee flexor strength in relation to knee extensor strength in the experimental groups. this may be due to the fact that there were muscle strength imbalances between the knee extensors and flexors at the start of the intervention (table v). the maintenance of functional rom is necessary for daily activity and efficiency of movement. there were no significant deviations in knee extension rom in relation to normative data before the exercise interventions and therefore no large changes were expected. knee flexion rom did however improve for all the subjects in both experimental groups and stayed approximately the same for the subjects in the control group (table v). it appears that exercise therapy does indeed play an important role in the treatment of rheumatic disease and in the fight against rheumatic invalidism. however, the primary purpose of the study was to determine which exercise mode, water-based exercise therapy or land-based exercise therapy, would be more effective in the treatment of ra. importantly, results indicate that disease activity was not exacerbated by the land-based exercises. it is however worthwhile noting that there were more clinically significant decreases in the joint counts for the subjects following water-based therapy than landbased therapy. in addition, the tjc increased in one of the subjects following land-based therapy. the greater reduction in joint swelling and tenderness in the water-based exercise group may be attributed to the reduction of joint loading occasioned by the buoyancy. in addition, the hydrostatic pressure of water immersion is considered to reduce oedema. 20 concerning the physical status of the subjects in the experimental groups, both exercise therapies had a positive influence on most of the physical status parameters measured. however, it would appear that the improvements in the water-based exercise group seemed slightly more substantial than those of the land-based exercise group. conclusion the results indicate that the benefits derived from both landand water-based exercises are very similar. the prescription of landbased exercises is feasible, especially when hydrotherapy is not possible or contraindicated. the appropriate land-based exercises do not appear to enhance disease activity. therefore the importance and unique benefits of land-based exercises should be considered when prescribing exercises for ra patients. it is possible that the exercise of choice for ra patients should not be water-based exercises alone, as believed in the past, but an optimal combination of landand water-based exercises. ideally, the contribution of landand water-based exercises to the overall programme of the ra patient should be manipulated according to the patient’s needs and disease activity at that period of time. finally, it is important to emphasise the fact that this was a preliminary study and therefore the sample was small and any changes in disease symptoms must be viewed in the context of the natural course of ra, where daily fluctuations in joint motion, swelling, pain and tenderness are not uncommon. however, all patients were on stable medication, thus eliminating the possibility of confounding results due to changes in medication. thus the results from this study indicate that future research focusing on the effects of various exercise modalities as well as the long-term effects of exercise interventions in the treatment of ra patients could prove valuable. references 1. nieman dc. exercise soothes arthritis. joint effects. acsms health fit j 2000;4(3):20-27. 2. thompson jm. arthritis: everything you need to know about arthritis. south africa: zebra press, 1998:23-46. 3. norceau l, martineau h, ro l, belzile m. effects of a modified dance based exercise on cardiorespiratory fitness, psychological state and health status of persons with rheumatoid arthritis. am j phys med rehab 1995;74(1):19-27. 4. giannini mj, protas ej. exercise response in children with and without juvenile rheumatoid arthritis: a case comparison study. phys ther 1992;72(5):365-372. 5. kirsteins ae, dietz fd, hwang sw. evaluating the safety and potential use of a weight-bearing exercise, tai-chi chuan, for rheumatoid arthritis patients. am j phys med rehab 1991;70(3):136-141. 6. gaudin p, leguen-guegan s, allenet b, baillet a, grange l, juvin r. is dynamic exercise beneficial in patients with rheumatoid arthritis? joint bone spine 2008;75:11-17. 7. van den ende chm, hazes jmw, le cessie s, et al. comparison of high and low intensity training in well controlled rheumatoid arthritis. results of a randomized clinical trial. ann rheum dis 1996;55:798-805. 8. ekdahl c, broman g. muscle strength, endurance, and aerobic capacity in rheumatoid arthritis: a comparative study with healthy subjects. ann rheum dis 1992;51:35-40. 9. del rincon id, williams k, stern mp, freeman gl, escalante a. high incidence of cardiovascular events in a rheumatoid arthritis cohort not explained by traditional cardiac risk factors. arthritis rheum 2001;44:27372745. 10. bacon pa, townend jn. nails in the coffin: increasing evidence for the role of rheumatic disease in the cardiovascular mortality of rheumatoid arthritis. arthritis rheum 2001;44:2707-2710. 11. hazes jmw, van den ende chm. how vigorously should we exercise our rheumatoid arthritis patients? ann rheum dis 1996;55:861-862. 12. tork sc, douglas v. arthritis water exercise program evaluation. a selfassessment survey. arthrit care res 1989;2(1):28-30. 13. klepper se. effects of an eight-week physical conditioning programme on disease signs and symptoms in children with chronic arthritis. arthrit care res 1999;12(1):52-60. 14. baillet a, zeboulon n, gossec l, et al. efficacy of cardiorespiratory aerobic exercise in rheumatoid arthritis: meta-analysis of randomized controlled trials. arthrit care res 2010;62(7):984-992. 15. ritchie dm, doyle ja, mcginnis jm. clinical studies with an articular index for the assessment of joint tenderness in patients with ra. q j med 1968;37:393-406. 16. lyngberg kk, ramsing bu, nawracki a, harreby m. safe and effective knee extension training in rheumatoid arthritis. arthritis & rheum 1994;37(5):623-628. 17. komatireddy gr, leitch rw, cella k, browning g, minor m. efficacy of low load resistive muscle training in patients with rheumatoid arthritis functional class ii and iii. j rheumatol 1997;24(8):1531-1539. 18. janse van rensburg dc, viljoen m, coertzen c, et al. efficacy of an exercise programme on the functional capacity and disease activity in females with rheumatoid arthritis. saoj 2010;28:685-691. 19. minor ma, hewett, je. physical fitness and work capacity in women with rheumatoid arthritis. arthrit care res 1995;8(3):146-154. 20. hall j, maddison pj, chapman k. arthrit care res 2010;9(3):206-215. introduction both the male and female marathons at the 2004 athens olympic games were run in the hottest conditions experienced in any world-class marathon events in recent memory. at the start of the woman’s race the temperature was 33°c, and the relative humidity (rh) was 31%; conditions were only slightly more favourable for the men’s events (30°c; rh 39%). by comparison, average early morning conditions during the 1996 olympic games in ‘hotlanta’ were comparatively cool although the humidity was high (average daily temperature 22°c; rh 83%). 1 when the race was run in 2004, the drinking guidelines then current 2-5 encouraged athletes to fully replace their body weight losses during exercise. if those guidelines were based on sound physiological principles, then it might be assumed that the athletes who performed the best in the 2004 olympic marathon races in athens would have followed those guidelines. in other words, these individuals would have consumed at least 1litre/h, amounting to a total of 2 2.5 litres during the race. to establish whether the world’s best runners adhered to the drinking guidelines current at that time, we retrospectively analysed the television broadcasts of the 2004 athens olympic marathons to determine the typical drinking behaviours of the top finishers in both races. as the television cameras followed the race leaders for the duration of the race, we were able to analyse only those athletes who were filmed at stations when they were running with the leading runners. to supplement these data, we also analysed the drinking behaviour of the pre-race favourite for the women’s marathon. this individual, the world record holder, retired from the race at 36 km. it appears that her inability to continue was likely due to the development of a limiting hyperthermia, but without progression to heatstroke. on the basis of prior, unsubstantiated observation, we postulated that these top-performing runners would drink less than advocated by the drinking guidelines. materials and methods all data from the race television broadcast for leading runners passing through each of the 15 seconding stations (located every 2.5 km after 5.0 km in the male and female athens 2004 olympic marathons) were recorded and stored on a sony pcg-grv7p computer using the dartfish 2.5.3.63 programme. the four top finishers in both the male and female marathon were targeted. in addition, the drinking behaviour of the female world marathon record holder, who retired from the race at 36 km, was also studied. original research article drinking during marathon running in extreme heat: a video analysis study of the top finishers in the 2004 athens olympic marathons abstract objective. to assess the drinking behaviours of top competitors during an olympic marathon. methods. retrospective video analysis of the top four finishers in both the male and female 2004 athens olympic marathons plus the pre-race favourite in the female race in order to assess total time spent drinking. one male and female runner involved in a laboratory drinking simulation trial. results. for the five female athletes, 37 of a possible 73 drinking episodes were captured. the female race winner was filmed at 11 of 15 drinking stations. her total drinking time was 23.6 seconds; extrapolated over 15 seconds this would have increased to 32.2 seconds for a total of 27 sips of fluid during the race. eighteen of a possible 60 drinking episodes for the top four male marathon finishers were filmed. the total drinking time for those 18 episodes was 11.4 seconds. a laboratory simulation found that a female athlete of approximately the same weight as the female olympic winner might have been able to ingest a maximum of 810 ml (350 ml.h -1 ) from 27 sips whilst running at her best marathon pace whereas a male might have drunk a maximum of 720 ml (330 ml.h -1 ) from 9 sips under the same conditions. conclusions. these data suggest that both the female and male 2004 olympic marathon winners drank minimal total amounts of fluid (<1 litre) in hot (>30ºc) temperatures while completing the marathon with race times within 2.5% of the olympic record. correspondence: professor t d noakes department of human biology sports science institute of south africa boundary road newlands, 7925 tel: +27 21 650-4557 fax: +27 21 686-7530 e-mail: timothy.noakes@uct.ac.za michelle van rooyen (phd) tamara hew-butler (phd) timothy d noakes (oms, mb chb, md, dsc, facsm, (hons), ffsem (uk) uct/mrc research unit for exercise science and sports medicine, department of human biology, university of cape town sajsm vol 22 no. 3 2010 55 the video broadcast was analysed for the following: • was the athlete’s drinking behaviour at the seconding station recorded on the broadcast? if not, an entry of no data (nd) was recorded (table i). • if the athlete was visible on the tape, did he or she take a drinking bottle at the specific seconding station in review? • if the athlete drank from the bottle, the number of times he or she drank from the bottle was recorded, as was • the total time in seconds that each athlete drank from each bottle at each seconding station. • whether or not the athlete sponged him or herself at the seconding station was also recorded. data were collated and analysed to determine the total time each athlete was observed to be drinking whilst on camera. it was assumed that this behaviour was consistent across the entire race. thus the behaviour of the athlete at the drinking stations that were captured on camera was extrapolated to those drinking stations at which he or she was not recorded. this allowed an estimate of the total time that each athlete spent drinking during the race. as near complete data were available for one athlete – the 40 kg winner of the female marathon – we performed a laboratory simulation in which a female marathon runner of similar weight (43 kg) reproduced the same drinking behaviour. this simulation was used to estimate the total volume of fluid that could be drunk in the same time that the female winner had been observed to be drinking during the olympic marathon. the female athlete ran at the equivalent of her best marathon pace whilst observing the edited video of the olympic female marathon. on each occasion that the female race winner drank, the tested runner exactly reproduced the behaviour. it soon became apparent that the female race winner held the drinking bottle to her mouth for just long enough to fill her mouth. therefore we performed an experiment to determine the maximum volume of fluid that our female subject could ingest, and which filled her mouth. this procedure was repeated with a male runner of 74 kg. in addition, in order to determine the limiting factors for drinking, we measured the peak flow rate that could be generated by applying maximum force with a single hand to two popular drink bottles, one large (1 000 ml) and one small (500 ml), for 3 5 seconds. we then calculated the volume of fluid ejected during this period and converted it to a flow rate in millilitres per second (ml/s). results despite the severe conditions in both athens olympic marathons, 66 (80%) of the 82 female and 81 (79%) of the 102 male entrants completed the race. to our knowledge, no runner developed heatstroke in either race although the female world record holder stopped running at 36 km, perhaps as a result of severe hyperthermia that resolved spontaneously once she stopped running. table 1 shows the drinking behaviours of the 9 runners that were analysed. data for the women’s race were more complete as 37 of the possible 73 (51%) drinking behaviours of the five studied runners were recorded on the television broadcast. only 30% of the males’ drinking behaviour was recorded. this reflected the different nature of the 2 races with 4 of the 5 women running in, or near, the lead group for the majority of the race. in contrast, 3 of the 4 top finishing males were close to the front for only the second half of the race. ta b le i. d ri nk in g be ha vi ou r at s ec on di ng s ta tio ns d ur in g th e a th en s 20 04 o ly m pi c m ar at ho n. s ta tio ns w er e si tu at ed e ve ry 2 .5 k m f ro m 5 k m a nd d at a ar e re po rt ed a s se co nd s sp en t d ri nk in g at e ac h st at io n r un ne r n am e c ou nt ry f in is hi ng tim e d rin ki ng st at io n no . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ♀ 1 m n og uc hi ja pa n 2: 26 :2 0 n d n d 0. 42 s p 5. 7 0. 98 s p 2. 4 s p 1. 24 s p 11 .0 8 n d n d 1. 72 s p n d ♀ 2 c n de re ba k en ya 2: 26 :3 2 n d n d n d n d n d n d 3. 66 0. 96 0. 88 n d n d 1. 42 n d ♀ 3 d k as to r u s a 2: 27 :2 0 n d n d n d n d n d n d n d n d n d n d n d n d n d n d n d ♀ 4 e a le m u e th io pi a 2: 28 :1 5 n d 0. 92 1. 18 s p 2. 98 1. 26 0. 68 1. 98 s p n d n d n d 0. 78 s p n d ♀ 5 p r ad cl iff e u k d n f 8. 3 1. 0 s p 11 .8 2 s p 6. 12 s p 3. 36 s p s p 2. 16 s p s p n d n d n d d n f d n f ♂ 1 s b al di ni ita ly 2: 10 :5 5 n d n d n d n d n d n d 0. 52 n d s p n d n d s p n d s p 3. 2 ♂ 2 m k efl ez ig hi u s a 2: 11 :2 9 n d n d n d n d n d s p n d n d s p n d n d 0. 62 n d s p n d ♂ 3 v l im a b ra zi l 2: 12 :1 1 n d n d n d n d n d 1. 02 1. 48 s p s p n d n d 0. 62 n d 2. 28 s p n d 0. 44 s p ♂ 4 j b ro w n u k 2: 12 :2 6 n d n d n d n d n d n d n d n d 1. 20 s p n d n d n d n d n d n d s p: u se o f a s po ng e or w at er o ve r th e bo dy , n d : n o da ta , t he a th le te in ge st ed fl ui d bu t t ot al d rin ki ng ti m e co ul d no t b e de te rm in ed fr om v id eo a na ly si s 56 sajsm vol 22 no. 3 2010 table ii, which summarises drinking behaviour over the course of the race, shows that whilst she was on camera, the female race winner drank for a total of 23.6 seconds at the 11 drink stations at which she was filmed – a total of 20 sips of fluid. in addition, she sponged herself at 6 stations. if it is assumed that this behaviour pattern was consistent throughout the race, extrapolation to the 4 stations at which she was not filmed would suggest that she drank for a maximum duration of about 32 seconds during the race – a total of 27 sips of fluid. similarly, the female world record holder was filmed at 10 of the 13 aid stations that she would have passed during the race. she took 18 sips of fluid for a total of 32.8 seconds of drinking, and sponged herself at 6 of the stations. thus her average drinking time at the 6 stations at which she drank was 5.4 seconds. had she drunk in the same fashion at 2 of the 3 stations at which she was not filmed, her total drinking time during the race would have been 43.6 seconds – a total of 24 sips. the female athlete who finished in fourth place was also successfully filmed at 9 of the 15 aid stations. her total drinking time was 9.78 seconds, and she took 7 sips of fluid. extrapolated to all 15 aid stations, her total drinking time would have been 18.2 seconds (13 sips). the less complete data for the male marathoners showed that the race winner drank at only 2 of the 5 stations at which he was filmed in the second half of the race (table i). this would amount to a total of 3.72 seconds of drinking, comprising 3 sips of fluid (table ii). extrapolating the same behaviour at 40% of the stations to the 15 drinking stations on the course, would have increased his total drinking time to 11.2 seconds from 9 sips of fluid. similarly, the second finisher drank at only 1 of the 4 stations at which he was filmed for a total of 1 sip lasting 0.62 seconds. the third finisher drank at 6 of the 7 stations at which he was filmed for a total of 8 sips of fluid lasting 5.84 seconds. extrapolating to the full race, he would likely have drunk at 13 of the 15 stations for a total duration of 12.6 seconds and 17 sips. thus the drinking behaviours of these 5 athletes ranged from total drinking times of 18 44 seconds whilst ingesting between 13 and 27 sips of fluid. laboratory simulation found that the average volume of a ‘sip’ for a female runner of 43 kg was 30 ml, and that of a male runner of 74 kg was 80 ml. thus the likely maximum amount of fluid ingested from 27 sips by the female race winner would have been approximately 810 ml, and that of the male race winner about 720 ml from 9 sips (table ii). the greatest estimated fluid volume (1 360 ml) was that of the male runner who finished in third place. the rate of flow from two different sports drink bottles was evaluated. the rate of flow from the 1 000 ml bottle was 100 ml/s while that from the 500ml bottle was 60 ml/s. only the smaller bottle would be used by marathon runners. a subsequent analysis using the same methods also found a similar flow rate of 50 ml/s from a similar drink bottle (mr lukas beis, university of glasgow: personal communication). accordingly, if the rate of fluid ingestion was limited by the peak flow rate of the drink bottles (probably ~50 60 ml/s) used by these athletes, and if the flow rate was always maximal when the bottle was in the athlete’s mouth, which seems improbable, then the maximal fluid volumes that could have been ingested by these athletes ranged table ii. summary of drinking behaviour during the athens 2004 olympic marathon runner total drinking time on camera extrapolated total drinking time extrapolated total volume ingested during the race (ml) seconds no. sips seconds no. sips max sip volume* peak flow rate volume** ♀ 23.601 20 32.0 27 810 1920 ♀ 6.922 6 ♀ nd3 ♀ 9.784 7 18.2 13 390 1080 ♀ 32.85 18 43.6 24 720 2640 ♂ 3.721 3 11.2 9 720 660 ♂ 0.622 1 ♂ 5.843 8 12.6 17 1360 780 ♂ 1.204 1.20 * based on average maximum volume of a sip in a ~40 kg female of 30 ml and of 80 ml in an ~70 kg male; ** based on peak flow rate of ~60 ml/sec from drinking bottle; prediction not possible on basis of available information; nd: no data. 58 sajsm vol 22 no. 3 2010 from 1 080 ml to 2 640 ml (430 1 300 ml/h) in the female runners, and from 660 ml to 780 ml (300 350 ml/h) in the male runners. the 1996 acsm guidelines current in 2004 advise that athletes should drink 1.2 l/h (equivalent to 2 620 ml during a 2:10:55 marathon by a male or to 2 920 ml during a 2:26:20 marathon by a female runner) to optimise performance. however, the true drinking behaviour of these world champions during international competition in extreme heat is estimated to be only 25% (male) to 31% (female) of these guidelines if drinking was limited by the size of the athlete’s mouths, and between 25% (male) and 66% (female) if drinking was limited by the rate of fluid delivery from the drinking bottles. what is more, if sweat rates were greater than 1.2l/h, as seems probable in these severe environmental conditions 6,7 and if athletes are expected to drink sufficiently to ‘replace all sweat losses during exercise’, 2 then the rates of fluid ingestion of these athletes would have been even more inadequate according to drinking guidelines then current. 3-5 more recently (february 2007), the acsm 8 published revised guidelines which propose that athletes should drink ‘to prevent excessive (>2% body weight loss from fluid deficit) dehydration and excessive changes in electrolyte balance from compromising performance and health’ (p.386). although the authors of the guidelines are reluctant to propose specific rates of fluid ingestion, they conclude that fluid ingestion rates of 400 800 ml.h -1 are ‘probably satisfactory for individuals participating in marathon length events’. compared with these guidelines the male race winner probably drank at an estimated rate of ~340 ml.h -1 and the female at ~350 ml.h -1 , rates which are below even the minimum range of these most recent acsm guidelines. it is also of interest that the smaller female athlete may have drunk at a faster rate than her larger male peer. discussion an important limitation of this study is that we did not record every drinking behaviour by all the top runners in both races in this event. the data from the men’s race in particular, were less than ideal as only 30% of all possible drinking behaviours were filmed. we were not able to measure the actual volumes of fluid ingested by these athletes during the races; rather we made extrapolations based on the evidence from the race video and a crude measure of the average size of a ‘sip’ in athletes of the appropriate size. nor did we measure the body weight changes in these athletes as a measure of dehydration. we did, however, accurately measure the maximum rate of fluid delivery from a typical sports drink bottle, similar to the type used in international marathon races. a subsequent study has confirmed this finding (lukas biel, university of glasgow: unpublished findings). the drinking behaviours of three of the leading female runners were far more complete with 29 (67%) of the 43 possible drinking behaviours captured on the tv broadcast. this, at least, allows for broad conclusions regarding the drinking patterns of elite female marathon runners during the world’s premier marathon race. our analysis suggests that in marathon races run in severe environmental conditions, the fastest female athletes spend between 18 and 45 seconds drinking – a total of ~30 sips of fluid during the race. this comprises about 0.5% of their total running time during the race. that they spent so little time drinking suggests that these elite female athletes do not place as much importance on fluid replacement during exercise as current drinking guidelines suggest they should. a more recent study of elite male marathon runners has confirmed that these athletes also drink for between 20 and 30 seconds during their marathon races (lukas beis, university of glasgow: manuscript in preparation). our laboratory simulation suggests that the total volume of fluid ingested by the female and male winners of these races was about 800 ml with an hourly rate of fluid ingestion of between 300 and 400 ml.h -1 . although these rates of fluid ingestion were only 25 30% of the then current acsm guidelines of 1.2l.h -1 , they are not different from rates recorded in runners competing before the 1970s. in that era, runners were actively discouraged from drinking as it was believed that drinking impaired athletic performance. 9 the estimated rates (~340 ml.h -1 for the male winner; ~350 ml.h -1 for the female winner) are also below the current range of 400 – 800 ml.h -1 considered ‘probably satisfactory’ in the revised (2007) acsm guidelines. interestingly, other studies 10-13 have also found that elite runners drink at rates that are at the low end of the acsm guidelines. to check the likely accuracy of these predictions, we measured the peak flow rates from popular drink bottles designed for use during athletic competition. these showed that flow rates of 60 ml.s -1 are probable. this would tend to confirm that subjects apply the bottles to their lips for sufficiently long (~1 second) to fill their mouths with a single sip of between 30 and 80 ml. on the other hand, if the drinking bottles provided fluid at the maximum rate (~60 ml/s) for the entire duration that they were applied to each athlete’s lips, then the absolute maximum volume of fluid that could have been drunk by the females rose substantially from ~640 ml to ~1 880 ml, with a maximum value of 2 640 ml (table ii). yet even this maximum value for the female winner was still only 66% of the amount recommended at the time. in contrast, this method of calculation caused the calculated amount of fluid ingested by the male runners to drop from ~1 040 ml to ~720 ml, or to less than 26% of the recommended volume. although the actual sweat rates of these athletes during these races were not reported, it is likely that their rates of fluid intake were substantially less than their sweat rates. for example, male and female runners running significantly more slowly in cooler conditions (25 32°c; rh 62 82%; wet bulb globe temperature index of 26.5 29.0°c) in atlanta, georgia, were reported to sweat at mean rates of 1.7 and 1.3 l.h -1 respectively. 7 these are among the highest sweat rates recorded in runners. it seems unlikely that the olympic marathoners in these races who were running very much faster in more severe conditions would have sweated at lower rates. at sweat rates of between 1.3 and 1.7 l.h -1 , but at fluid ingestion rates of only 300 800 ml.h -1 (table ii), these athletes would have lost between 0.5 and 1.4 kg.h -1 , and thus would have ‘dehydrated’ by at least 3 4.5%. these predictions match findings in other winning marathon runners. 10-13 thus, we conclude that athletes can win major competitive events run in extreme environmental conditions, even when consuming substantially less fluid than the recommended, developing an estimated 3 5% dehydration. this level of dehydration appears to pose no obvious risk to the individual’s health, nor does it appear to impact performance. this is compatible with the theory that dehydration has a smaller impact on performance in trained athletes than is currently believed. 14-15 conversely, it is in contradiction to the theory that a 4% level of dehydration will cause a 30 50% reduction in exercise capacity (fig. 4 16 ) whereas a 5% weight loss will cause a reduction of between 45 and 65%. were these data correct, the 60 sajsm vol 22 no. 3 2010 female winner of the athens olympic marathon should have finished the race in between 3:10:14 and 4:01:24, rather than in 2:26:20. it therefore appears that the data on which these predictions are based do not apply to the world’s best athletes. one of the reasons why world-class athletes may be quite unable to drink at the high rates proposed by these guidelines may simply be that such high rates produce discomfort in athletes running at high exercise intensities. indeed, one of the core studies used by the acsm to justify high rates of fluid ingestion during exercise concluded that runners were unable to sustain rates of fluid ingestion of 1.2 l.h -1 for more than about 70 80 minutes. 17 thus the authors wrote: ‘all of the runners experienced extreme sensations of fullness during the final five or six feedings. at the end of 100 minutes of running and feeding, it became apparent that further attempts to ingest fluids would have been intolerable’ (p. 522). on the other hand, drinking ad libitum at lower rates (~250 ml every 5 km; 500 700 ml.h -1 for men and women respectively) during experimental 40 km running trials produced intestinal distress in only 2 of 12 subject. 17 but when subjects combined walking, jogging and resting in the shade during a competitive 25 km military route march in 44°c, they were able to drink up to 1.2 l.h -1 without developing symptoms of intestinal discomfort (nolte h et al.: manuscript submitted). this suggests that it is the act of running which causes intestinal symptoms when the rates of fluid ingestion are high. alternatively, these guidelines may have encouraged a drinking behaviour that elite athletes are unable to follow simply because humans evolved specifically to be able to run in the heat without requiring concurrent fluid replacement. thus one theory 18 holds that the ability to sweat and, as a consequence, to become dehydrated, provided humans with a critical evolutionary advantage since it allowed humans to add high-quality protein to their diets. thus their ability to sweat, and therefore to remain in thermal balance during prolonged exercise in the heat, allowed ancestral humans hunting on the african plains to chase large, non-sweating antelope until their exhaustion presumably as a result of hyperthermia. 19 sweating allowed humans better to regulate their body temperatures during such exercise in extreme dry heat (up to 46°c 20 ), thereby avoiding the hyperthermia that caused their prey to become paralysed, and hence dispatchable at close quarters. the remarkable performances of the tiny, light-boned, elite marathon runners of today, like the 40 kg winner of the 2004 athens olympic women’s marathon, mizuki noguchi, in extreme heat suggest the continued presence of these remarkable evolutionary adaptations. 21 high sweating rates, that are not reduced by a developing dehydration, 17,22,23 and the ability to run in extreme heat for up to 6 hours without significant fluid ingestion 20 seem to confirm that humans are remarkably well adapted for running in dry heat, as again confirmed by the exceptional performances of real athletes in actual olympic competitions. elsewhere 24 we have also shown that elite kenyan distance runners drinking ad libitum at rest and during training ingest fluid at rates that appear to be low compared with modern drinking guidelines. references 1. sparling pb. environmental conditions during the 1996 olympic games: a brief follow-up report. clin j sport med. 1997;7(3):159-161. 2. armstrong le, epstein y, greenleaf je, et al. american college of sports medicine position stand. heat and cold illnesses during distance running. med sci sports exer 1996;28(12):i-x. 3. casa dj, armstrong le, hillman sk. national athletic trainers association position statement: fluid replacement for athletes. j athl train 2000;35:212-224. 4. convertino va, armstrong le, coyle ef, et al. american college of sports medicine position stand. exercise and fluid replacement. med sci sports exer 1996;28(1):i-vii. 5. american college of sports medicine, american dietetic association, dietitians of canada. joint position statement: nutrition and athletic performance. med sci sports exerc 2000;32(12):2130-2145. 6. fowkes godek s, bartolozzi ar, godek jj. sweat rate and fluid turnover in american football players compared with runners in a hot and humid environment. br j sports med 2005;39(4):205-211. 7. millard-stafford m, sparling pb, rosskopf lb, snow tk, dicarlo lj, hinson bt. fluid intake in male and female runners during a 40-km field run in the heat. journal of sports sciences. 1995;13(3):257-263. 8. sawka mn, burke lm, eichner er, maughan rj, montain sj, stachenfeld ns. american college of sports medicine position stand. exercise and fluid replacement. med sci sports exerc 2007;39(2):377-390. 9. noakes td. lore of running. 4th ed. champaign, il: human kinetics publishers, 2003. 10. wyndham ch, strydom nb. the danger of an inadequate water intake during marathon running. s afr med j 1969;43(29):893-896. 11. pugh lg, corbett jl, johnson rh. rectal temperatures, weight losses, and sweat rates in marathon running. j appl physiol 1967;23(3):347352. 12. muir al, percy-robb iw, davidson ia, walsh eg, passmore r. physiological aspects of the edinburgh commonwealth games. lancet 1970;2(7683):1125-1128. 13. buskirk er, beetham wpj. dehydration and body temperature as a result of marathon running. medicina sportiva 1960;xiv(9):493-506. 14. sharwood ka, collins m, goedecke jh, wilson g, noakes td. weight changes, medical complications, and performance during an ironman triathlon. br j sports med 2004;38(6):718-724. 15. noakes td. dehydration during exercise: what are the real dangers? clinical journal of sport medicine 1995;5(2):123-128. 16. sawka mn, montain sj. fluid and electrolyte supplementation for exercise heat stress. am j clin nutr 2000;72(2 suppl):564s-572s. 17. costill dl, kammer wf, fisher a. fluid ingestion during distance running. arch environ health 1970;21(4):520-525. 18. heinrich b. racing the antelope. first. new york: harper collins publishers inc., 2001. 19. gonzalez-alonso j, teller c, andersen sl, jensen fb, hyldig t, nielsen b. influence of body temperature on the development of fatigue during prolonged exercise in the heat. j appl physiol 1999;86(3):1032-1039. 20. foster c, foster d. speaking with earth and sky. cape town: david phillips publishers, 2005. 21. bramble dm, lieberman de. endurance running and the evolution of homo. nature 2004;432(7015):345-352. 22. eichna lw, bean wb, ashe wf, nelson n. performance in relation to environmental temperature. bull johns hopkins hospital 1945;76:25-58. 23. montain sj, coyle ef. influence of graded dehydration on hyperthermia and cardiovascular drift during exercise. j appl physiol 1992;73(4):13401350. 24. fudge bw, easton c, kingsmore d, et al. elite kenyan endurance runners are hydrated day-to-day with ad libitum fluid intake. med sci sports exerc 2008;40(6):1171-1179. sajsm vol 22 no. 3 2010 61 introduction non-communicable diseases (ncds) have become an increasing concern in south africa.1 despite the apparent rise of ncds2 and the alarming prevalence of both obesity and physical inactivity in south africans,3 even from more disadvantaged communities,4 there are limited data on successful physical activity interventions in preventing and reducing ncds in these settings. physical activity has been linked to the prevention and reduction of these diseases,5 and the problem of inactivity has been demonstrated throughout the life-course in south africans, with only 50% of south african secondary school learners reporting participation in weekly physical education.6 school-based physical activity interventions are one of the many strategies employed in both developed and developing settings to address the rise of ncds,7,8 although there is limited literature from developing settings. within school-based interventions, teachers play a pivotal role in the implementation of these interventions and are acknowledged as an important source of information regarding perceptions of barriers to and factors facilitating school-based physical activity interventions9 and the promotion of physical activity in the school environment.10 original research article evaluation of a school-based physical activity intervention in alexandra township abstract objectives. non-communicable diseases and limited participation in school physical education have become increasing concerns in south africa. in response to these concerns, a schoolbased physical activity intervention, healthnutz, was implemented in three primary schools in alexandra township, johannesburg. evaluation of healthnutz included assessing its feasibility and acceptability, and short-term changes in learners’ physical fitness, knowledge and attitudes. methods. to assess feasibility and acceptability, a situational analysis and focus groups with teachers and programme monitors were conducted. pre-post fitness testing (3-month interval) was conducted with learners, and a questionnaire assessed changes in learners’ knowledge, attitudes, self-efficacy, and perceived barriers to physical activity, in control and intervention schools. results. at implementation, teachers identified the need for more physical activity in the school environment and were positive about healthnutz. follow-up focus group discussions suggested that it was positively impacting teachers, learners and the school in general. scores for sit and reach (p<0.001), sit ups (p<0.02) and shuttle run (p<0.0001) improved significantly in incorrespondence: dr catherine draper uct/mrc research unit for exercise science and sports medicine sports science institute of south africa boundary road newlands 7700 cape town tel: +27 21 650 4570 e-mail: catherine.draper@uct.ac.za catherine e draper (phd) 1 lauren de kock (ma)2 anna t grimsrud (mph) 1 michael rudolph (mph, msc, specialist in community dentistry)2 simon nemutandani (mph, mchd)2 tracy kolbe-alexander (phd)1 estelle v lambert (phd)1 1uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town 2health promotions unit, school of public heath, university of the witwatersrand, johannesburg tervention but not control schools. a significant decrease was observed in learners’ perceived external barriers to physical activity (p<0.0001) along with a positive change in learners’ self-efficacy for physical activity (p<0.05). conclusions. healthnutz raised awareness of the importance of physical activity in intervention schools. findings indicate that even limited exposure to a physical activity intervention can lead to a significant improvement in aspects of learners’ fitness, knowledge, attitudes and perceptions regarding physical activity. furthermore, training and support of teachers needs to be nonjudgemental and empowering. 12 sajsm vol 22 no. 1 2010 sajsm vol 22 no. 1 2010 13 the discovery healthy lifestyle programme the discovery healthy lifestyle programme (dhlp), a corporate social investment project from a major national private health insurer, was developed in 2006 as a national pilot project of the community health intervention programmes (chips).11 healthnutz (fig. 1), one of the chips’ interventions for primary (elementary) schools, was developed in response to the reality that physical education in south africa was reformulated in 2004, to be delivered by classroom teachers as part of an integrated curriculum. the dhlp programme was specifically designed to support teachers in incorporating physical activity and nutrition education into the life orientation (lo) curriculum, into which these topics were placed. alexandra township (‘alex’) located in johannesburg, gauteng province, was selected as one of the urban pilot communities for the dhlp. community concerns in alex include overcrowding, poor sanitation, high levels of crime and violence, unemployment, poverty, substance abuse, and an estimated hiv/aids prevalence of 40%.12,13 three primary schools in alex were purposively selected by the gauteng department of education as healthnutz intervention schools, and three control schools were recruited. evaluation aims evaluation of healthnutz included assessing its feasibility and acceptability in schools, along with changes in physical fitness, knowledge and attitudes of the learners. methods situational analysis the situational analysis was done on the physical activity environment of each intervention school (may 2006), which involved a combination of direct observation and consultation during school time with a member of the school staff. this was carried out using a quantitative tool developed for use in south african schools, with specific focus on implementation of physical activity and sport in the timetable, the availability of sporting equipment and facilities, and the distribution and accessibility of healthy food within the school. owing to difficulties in recruiting control schools, the situational analysis was not carried out at these schools. focus groups a total of five focus groups were conducted (in english) preand 6 months post-implementation (may and november 2006). participants in the focus groups were teachers (n=39) and programme monitors (n=2). for the pre-implementation focus group (n=10), each school was asked to request participation of four teachers who had undergone healthnutz training. all teachers who had been involved in implementing the healthnutz programme were asked to participate in the post-implementation focus groups (n=8, n=16, n=5). the teacher questionnaire was distributed to all teachers at intervention schools; 38 completed questionnaires were returned (46% response rate). fig.1. the healthnutz model. notes of the group discussion were taken by two facilitators as recording via audio or video may have inhibited discussion (it was the first meeting between the research team and teachers). notes were taken during the three post-implementation focus groups, and based on the relationship established with teachers, these were recorded via audio. at the same time, a focus group was conducted with the programme monitors. topics for the initial focus group with teachers covered the following: • relative importance of physical activity • perceptions of and expectations about healthnutz, including training • factors that could enable or hinder the success of healthnutz. post-implementation focus groups with the teachers covered the following: • healthnutz implementation in their school • strengths or limitations as healthnutz leaders • general impact of healthnutz on school environment, learners, teachers and community. the focus group with the programme monitors addressed the following: • relationship with schools, chips, and the research team • strengths and weaknesses of healthnutz • enabling factors and barriers to healthnutz implementation. summaries of the focus group discussions were generated and these, along with summaries of the first focus group, were circulated to other members of the research team for verification and approval. the topics mentioned above served as a framework for the analysis of the focus group summaries, which was done using a qualitative content analytic approach. teacher questionnaire a questionnaire was used for the formative assessment of teachers, and was distributed to the teachers one month after programme implementation. questions were asked about the following: • demographic and professional information • views on physical activity and the curriculum • personal lifestyle risk profiles. learners: fitness testing and questionnaire all learners participating in this study were in grades 4, 5 and 6 from the three intervention schools (n=423) and two control schools (n=85). the low number of learners at control schools was attributable to scheduling conflicts. learner fitness testing was conducted at all five schools preand 4 months post-implementation (july and november 2006) using the eurofit fitness testing protocol14 which has been adapted for use in a south african setting,15 and comprised the following: • sit and reach (flexibility) • cricket ball throw (upper body strength) • standing long jump (lower body strength) • sit-ups (abdominal strength) • 10 metre shuttle run (cardiovascular fitness) • height and weight. a physical activity questionnaire was administered in a group setting at the intervention and control schools with the assistance of local trained fieldworkers who were fluent in the main languages spoken by learners. this questionnaire, developed by the research team, was based on validated questionnaires that have been used in other similar studies with grade 4 6 learners and was piloted in a similar setting in cape town. the questionnaire included questions on the following: • sociodemographics, such as living conditions and home language • physical activity behaviour • sedentary behaviour • knowledge and gender attitudes regarding physical activity • perceived barriers to physical activity • exposure to physical activity messages. repeated measures analyses of variance (statistica v8; statsoft, tulsa, ok, usa, sigma-restricted parameterisation) were used to analyse changes in fitness measures, as well as height and weight. with regards to learners’ questionnaire responses, a score was given for each affirmative response. these scores (all related to physical activity) were grouped into the following: external barriers, self-efficacy, knowledge and gender attitudes. parametric and nonparametric (mann-whitney u test) statistics were performed on the changes in these scores, pre and post. ethical approval for this research was obtained from the research ethics committee in the faculty of health sciences, university of cape town (rec ref: 486/2005). permission to conduct this research was obtained from the gauteng department of education. parental consent (written) was obtained for all the learners involved. results school environment key results from the situational analysis of the schools’ physical activity environment are presented in table i. the three intervention schools were situated in different locations in alexandra, leading to disparity in availability of resources. two schools had a surplus of new sporting equipment that had been donated approximately 6 months earlier (some of which was for sports not commonly played in this area, such as baseball and badminton), and were located directly adjacent to accessible community sports facilities. in addition, there was sufficient space for physical activity, although the surface of these spaces was generally concrete or tar. the third school, located in a more densely populated part of alexandra, had very little space between classrooms, minimal sporting equipment and was further away from community sports facilities. during one of the focus groups with teachers, the importance of support for healthnutz-trained teachers was emphasised. based on their past experience with other school interventions, teachers highlighted that assistance from healthnutz monitors should focus on encouragement and recognition rather than on criticism and disapproval. thus, a fear of being criticised for not using the equipment correctly may have prevented teachers from making use of any new equipment. pre-implementation focus groups: teachers the discussion revealed that as physical activity is only one component of the life orientation curriculum, it has been allocated far less 14 sajsm vol 22 no. 1 2010 sajsm vol 22 no. 1 2010 15 time in the curriculum and only a small percentage of teachers are involved. teachers expressed concern that children had become less active in recent years and reported that the number of overweight children had increased, but saw this problem alongside undernourished learners who rely on the school feeding scheme. furthermore, they spoke of limited opportunities for learners to be physically active in alexandra, due to space constraints, a lack of facilities and safety. teachers were aware that they themselves were overweight as a result of inactivity and poor dietary habits, and acknowledged the importance of their position as role models for healthy lifestyles for the learners. due to the identified need for more physical activity in the school environment, teachers were positive about the healthnutz programme and training they received. they expressed confidence in its successful implementation, despite some concerns about how it would fit into their already busy timetable. teachers were able to identify a wide range of possible benefits of the programme for themselves and the learners. these included the promotion of healthy lifestyles and increased awareness of the importance of physical activity. with specific reference to learners, the benefits included both health and psychosocial outcomes, such as discipline, keeping out of trouble, and enjoyment. even at this stage of implementation, it seemed clear that the healthnutz programme had raised awareness about the importance of physical activity and healthy lifestyles. ‘children in our school used to eat junk food. but since we’ve introduced this, they know how to choose the best food…after break they used to have this plastic [bag] with yellow chips and whatever, but since then it has reduced, and the sweets as well…we encourage them to buy fruit and we also talk to the vendors to sell fruits to them…they come to you to show you, because you show them that you can afford an apple or whatever a day…and they come and show you “i’ve bought this”’(teacher). follow-up focus groups: teachers the follow-up focus groups with teachers painted a rather complex picture of the implementation process, and it is worth noting that environmental differences between schools mentioned previously did not appear to have an impact on the perceptions of teachers from the three intervention schools. reviewing the teachers’ impressions of the impact of the programme on the school, it appeared that the programme was being implemented as intended. teachers reported that their schools had become healthier environments due to raised awareness and some environmental changes relating to nutrition. these changes included vendors selling fruit to learners in addition to their usual fare of highly processed, high fat, savoury or sweet foods. teachers expressed feelings of improved health and self-efficacy regarding their own activity levels. one teacher commented that the programme had helped to improve relationships between learners and teachers. ‘i think the relations with the learners and the teachers sometimes improved with this programme. you find that some of the learners are so scared of the teachers, but once you do with them the healthnutz programme, they find you being friendly, and the ice starts to melt.’ (teacher). the positive impact of the programme activities on the learners was also noticeable to teachers, and learners were reported to enjoy the activities. teachers believed that the healthy eating component of healthnutz was well received, with learners making healthier food choices. teachers from one school commented that the healthy lifestyle message was also reaching the learners’ parents and caregivers. ‘what you teach them, they pass on to their parents, which is a very good thing…you hear a mother saying “hey, my child was saying this about food and that and that…” they also remind us, “teacher, you are eating this and this, but you said we shouldn’t”…i changed my eating habits, and i used to like coke, and [trainer’s name] discouraged a lot us from drinking a lot of coke [coca cola]. he’s saying like even if you can take it and put it in the car’s battery… so i’m starting to drink more water.’ (teacher). however, it was quite clear from the focus group discussions that the programme had many implementation challenges. in addition to the difficulty of fitting healthnutz into the timetable, many of the obstacles related to teachers. these included the loss of teachers who were trained in healthnutz (either no longer taught lo or left the school), lack of motivation among some teachers who were trained but did not implement the programme, teachers who were implementing healthnutz without training, and teachers lacking confidence to direct activities. this lack of confidence could have been due to the teachers themselves being overweight and inactive. teachers also mentioned having difficulty in controlling big groups of learners and maintained that there was not sufficient equipment and/or space. ‘it’s mixed with the teachers. there’s those who are keen on it, there are those who want to do it because they are also aware of the benefits that physical activity would have on a child’s life, on their life as well. there are those who are just saying “this is extra work for me, i’d rather not get too involved”. some of the teachers, they are very reluctant. and also the timetable…almost all of the schools table i. situational analysis of the physical activity environment intervention school 1 intervention school 2 intervention school 3 learners 1187 1051 1024 teachers 29 28 25 learner / teacher ratio 41 38 41 facilities* 4 playgrounds (paved/cement) 2 playgrounds (paved/cement) 1 playground (paved/ soccer field, hall cement) equipment rugby balls, tennis balls, soccer balls, complete cricket kit (pads, gloves, sports kit, cricket kit netballs, beacons, cricket wickets, balls, wickets, bats), complete softball kit cricket bats and pads, frisbee, (helmets, mits, balls, bats), cones, plastic bats, clipboard, whistles, scales tennis balls and racquets, rugby balls *all share off-site facilities with other schools and community. complain about the timetable, it clashes with their own timetable.’ (monitor). ‘using of the equipment…they don’t use the equipment at all…some of them, not all of them, some of them, they don’t use the equipment. that might go with the confidence of some of the teachers, as you said, that they want to have [programme monitor’s name] there, they want to have [programme monitor’s name] there, to start them off and things. so maybe that might be the reason that most of the teachers they don’t think they can be able to do it without assistance. that might be one of the issues. they don’t even want to use the equipment. they’d rather have the kids run around and jumping and skipping than for them to do more sports skills.’ (monitor). follow-up focus groups: monitors the monitors’ involvement with the healthnutz programme (from the initial training to implementation and assistance with evaluation) enabled them to provide an overall perspective of the programme that was likely to be more objective than the teachers’ point of view. monitors’ perceptions on the implementation of healthnutz did not differ between the 3 schools, and they described a range of attitudes of teachers which varied from the more passionate, often younger ones acting as role models for the learners, to those who wanted the monitors to do everything for them. these teachers were not motivated to implement the programme, even though they participated in the training. the monitors suggested that some teachers participated in the training simply because it gave them a break from school and that there was an incentive for them to get a free t-shirt and certificate. furthermore, monitors felt that some teachers perceived the programme as extra work and were resistant to change. the monitors felt that teachers had sufficient equipment for healthnutz and that group sizes were manageable. they argued that these factors should not have inhibited them from implementing the programme. lack of confidence was also raised by the monitors. they suggested that teachers may be afraid to make mistakes, especially if these would be recorded as part of a ‘bad’ report by the monitors. the role of the monitors was described by some teachers as helpful, supportive and encouraging while others saw them as ‘assessors’ whose role was to judge their performance; thus some teachers referred to the monitors’ visits, as ‘assessments’. these differences in perception may have resulted in the monitors’ visits causing ‘performance anxiety’ instead of boosting confidence which they sorely needed. ‘some of them…that’s why they’re very reluctant, because when we are there, they think that we are there to write bad report about them. because some of them, they don’t exactly know the actual steps of conducting a session. so when they make mistakes, they feel like there’s something that…they think we are going to write about them when we submit our reports. that’s why are very reluctant…always want us to conduct a session. i think that’s the reason. because when we go there we usually have some note book to take some notes, like what kind of exercise does the teacher do, and also what kind of warm-ups, so we take some notes.` (monitor). questionnaire: teachers results from the teachers’ questionnaire are presented in table ii. fitness testing: learners pre-post fitness testing results for learners are presented in table iii. for sit-and-reach, scores in the control group decreased from prepost whereas they increased significantly in the intervention group (p<0.001). baseline sit-and-reach scores, however, were higher in the control group. these results were adjusted for the potential confounding variable of gender. sit-up scores also improved significantly in the intervention group, whereas there was no significant improvement in sit-up scores in the control group (p<0.02). learners from intervention schools also had significantly faster shuttle run scores following the intervention; this was not demonstrated in the control group (p<0.0001). in both groups, long jump (p<0.0001) and ball throw (p<0.002) scores increased from preto post-intervention. there were no effects of the intervention on these scores. questionnaire: learners table iv outlines learners’ questionnaire responses for external barriers to and self-efficacy for physical activity, as well as knowledge of and gender attitudes towards participation in physical activity. there table ii. teacher questionnaire results views on physical activity and the curriculum yes believe that physical activity and nutrition are catered for in the curriculum 29% feel adequately trained to teach physical activity and nutrition 45% feel that physical activity should be part of life orientation 82% main barriers to physical activity school lacks facilities 63% school lacks equipment 50% learners can’t afford shoes or kit 68% lifestyle habits and health i eat fresh fruit and vegetables daily, and only eat unhealthy foods very occasionally or not at all 18% i maintain a good balance in my diet by eating foods like fresh fruit and vegetables but i also eat unhealthy foods a fair amount 53% i don't eat enough healthy foods like fresh fruit and vegetables but i intend to get a better balance in my diet over the next 12 months 13% unhappy or unsatisfied with their weight 50% i try to exercise several times each week 16% i exercise only occasionally or not at all but i intend to start doing more from now on 42% rate their general state of health as fair 34% rate their general state of health as good 45% 16 sajsm vol 22 no. 1 2010 sajsm vol 22 no. 1 2010 17 was a significant lowering of perceived external barriers to physical activity in the intervention but not the control group (p<0.0001). similarly, learners from intervention schools experienced a positive change in self-efficacy for physical activity (p<0.05), not demonstrated in the control group. the interpretation was not different, irrespective of whether results were analysed using non-parametric or parametric analyses, and gender did not influence these results. knowledge concerning physical activity increased similarly in both the intervention and control groups. however, learners in the intervention group showed an improvement in gender attitudes towards participation in physical activity, not demonstrated by the control group (p<0.001). table iii. learner anthropometrics and fitness testing results outcome variable intervention / control n pre: mean pre: sd post: mean post: sd p-value for group x time interaction height (cm) control 8 142.4 ± 8.5 144.9 ± 9.9 p=0.602 1 intervention 4 142.9 ± 8.4 145.2 ± 9 2 2 weight (kg) control 8 36.9 ± 8.4 37.1 ± 8.4 p<0.005 5 intervention 4 35.8 ± 8.6 37.1 ± 8.7 2 3 sit and reach (cm) control 8 24.5 ± 16 14 ± 9.7 p<0.001 3 intervention 4 14.6 ± 5.9 19 ± 6.8 1 0 sit ups (in 30 seconds) control 8 15.2 ± 5.4 15.5 ± 5.1 p<0.02 3 intervention 4 16 ± 6 17.8 ± 6.1 2 6 shuttle run (seconds) control 8 47.2 ± 4.6 48.6 ± 5.5 p<0.0001 3 intervention 4 48.5 ± 5.1 46.2 ± 4.6 0 5 long jump (cm) control 8 120.4 ± 18.8 135 ± 19.7 p=0.135 4 intervention 4 124.6 ± 25.7 134.3 ± 25.7 0 9 ball throw (m) control 8 21.7 ± 6.2 21.8 ± 6.9 p=0.106 5 intervention 4 22 ± 7.2 23.1 ± 7.5 1 3 18 sajsm vol 22 no. 1 2010 discussion the findings of this evaluation demonstrate that healthnutz was largely implemented as intended and that the implementation of healthnutz in these schools was perceived as meaningful and useful by the teachers. according to teachers, it has raised awareness in teachers, learners and parents of the importance of physical activity, alongside competing health and social priorities, indicating that the healthnutz programme is an acceptable programme for these schools. the schools, principals and the department of education seemed willing to incorporate more physical activity into their school environment and curriculum, even with its additional demands on the teachers and time in the school day. the questionnaire results from teachers validate the qualitative findings and highlight the need for table iv. learner questionnaire results intervention control perceived external barriers to physical activity* pre post pre post for me, it is too dangerous to walk to school or play outside 31% 27% 39% 33% for me, it is too far to walk to school 31% 31% 52% 60% there is no place outside to play near my home or school 62% 35% 47% 43% i am not allowed to stay after school to play sports 48% 30% 47% 45% external barriers change score intervention control mean differences (sd) -0.57 (1.28) 0.12 (1.3) p-value for between group differences p<0.001 intervention control self-efficacy for physical activity* pre post pre post i do not have enough time to do sport or play games with my friends 52% 36% 43% 42% i have fun when i am doing physical activity 84% 86% 77% 87% i can do physical activity that makes me sweat and breath hard 55% 66% 57% 68% i get tired very quickly when i do physical activity 34% 35% 47% 45% self-efficacy change score intervention control mean differences (sd) 0.3 (1.29) -0.01 (1.19) p-value for between group differences p<0.05 intervention control physical activity knowledge** pre post pre post you are doing physical activity when you are playing sport, running or going to the gym 61% 65% 57% 70% you are doing physical activity when you play games with your friends, e.g. skipping, other traditional games 72% 75% 66% 71% walking is physical activity, e.g. walking to / walking home from school 57% 66% 61% 68% doing chores at home, e.g. fetching water, chopping wood, is physical activity 47% 51% 46% 51% dancing is physical activity 63% 68% 66% 71% it is important to do physical activity in order to keep my body healthy 89% 90% 86% 87% i should do at least 30 minutes of physical activity every day 59% 62% 55% 47% knowledge t-test scores (p=0.76) intervention control mean differences (sd) 0.56 (2.33) 0.47 (2.11) p-value for between group differences p=0.76 intervention control gender attitudes towards participation in physical activity** pre post pre post boys are better at physical activity than girls 49% 49% 56% 48% girls should not sweat and breathe hard when they do physically activity 38% 28% 25% 21% gender attitude t-test scores (p<0.001) intervention control mean differences (sd) -0.34 (1.34) 0.27 (1.31) p-value for between group differences p<0.001 * % who answered ‘yes’ ** % who answered ‘true’ sajsm vol 22 no. 1 2010 19 an intervention that capacitates teachers within lo, and that takes into account the substantial barriers to physical activity relating to resources. teachers’ responses regarding their state of health further emphasises the need for them to be included in any health promotion endeavours within the school environment. many of these findings are comparable with findings from other similar studies that have highlighted the importance of stakeholder involvement, a supportive school environment, effective training of teachers, and programme alignment with existing curricula.7,8 challenges included teacher constraints, both in terms of time and other responsibilities, and getting teachers involved.7,9,16,17 physical barriers mentioned by teachers in this study, such as learners not having the appropriate clothing for physical activity,7 space constraints,16,17 limited facilities and equipment, limited funds and difficulty controlling big classes17 are also common challenges experienced amongst those implementing school-based physical activity interventions. results for learners indicate that limited (4 months) exposure to a physical activity intervention can make a significant impact on fitness, knowledge and gender attitudes regarding physical activity. in addition, the results relating to external barriers to and self-efficacy for physical activity are encouraging as they show that perceptions of physical activity were open to change even when external circumstances remained the same. few other intervention studies report significant changes such as these after such limited exposure. the majority of these studies demonstrate changes as a result of interventions lasting in the region of a year for cardiovascular fitness18 and psychosocial measures,19 but sometimes up to 3 years for psychosocial variables.20 limitations of this study include the lack of rigorous monitoring data to support the evaluation, limited data collected from control schools, and the small number of learners tested at control schools. this study would have also benefited from more in-depth qualitative investigation as well as a longer exposure to healthnutz. future research could include assessment of the long-term sustainability of the programme in these schools. follow-up visits to these schools revealed that while the programme is no longer being implemented as originally intended (incorporated into the life orientation curriculum), there may well have been changes in the physical activity culture of these schools. future research would do well to investigate these changes. implications of findings these findings highlight that challenges and constraints in the school environment are similar in both developed and developing settings. in schools where resources are limited and where available resources are allocated to other school and community concerns taking pre cedence over healthy lifestyles, those promoting health in the school environment need to prioritise collaboration between public health care practitioners and key stakeholders in schools and communities. this is in order to not only effectively monitor and evaluate interventions in the school environment, but also to keep healthy lifestyles high on the school agenda. regarding the inclusion of teachers in school-based interventions, the process of recruiting, training and assisting teachers needs to be empowering and one that builds capacity and develops confidence in their ability to adopt new skills and roles within the school environment and in their community. programme monitoring requires a balance of accurately recording observed behaviour of teachers, but which also gives them support and encouragement. references 1. mayosi bm, flisher aj, lalloo ug, sitas f, tollman sm, bradshaw d. the burden of non-communicable diseases in south africa. lancet 2009;374(9693):934-947. 2. kruger hs, puoane t, senekal m, van der merwe mt. obesity in south africa: challenges for government and health professionals. public health nutr 2005;8(5):491-500. 3. joubert j, norman r, lambert ev, et al. estimating the burden of disease attributable to physical inactivity in south africa in 2000. s afr med j 2007;97(8 pt 2):725-731. 4. steyn k, levitt ns, hoffman m, et al. the global cardiovascular diseases risk pattern in a peri-urban working-class community in south africa. the mamre study. ethn dis 2004;14(2):233-242. 5. haskell wl, blair sn, hill jo. physical activity: health outcomes and importance for public health policy. prev med 2009;49(4):280-282. 6. amosun sl, reddy ps, kambaran n, omardien r. are students in public high schools in south africa physically active? outcome of the 1st south african national youth risk behaviour survey. can j public health 2007;98(4):254-258. 7. naylor pj, macdonald hm, zebedee ja, reed ke, mckay ha. lessons learned from action schools! bc – an ‘active school’ model to promote physical activity in elementary schools. j sci med sport 2006;9(5):413423. 8. franks al, kelder sh, dino ga, et al. school-based programs: lessons learned from catch, planet health, and not-on-tobacco. prev chronic dis 2007;4(2):a33. 9. boyle se, jones gl, walters sj. physical activity among adolescents and barriers to delivering physical education in cornwall and lancashire, uk: a qualitative study of heads of pe and heads of schools. bmc public health 2008;8:273. 10. cale l. physical activity promotion in schools: pe teachers’ views. phys educ sport pedagog 2000;5(2):158-168. 11. draper ce, kolbe-alexander tl, lambert ev. a retrospective evaluation of a community-based physical activity health promotion programme. j phys act health 2009;6(5):578-588. 12. richards r, o’leary b, mutsonziwa k. measuring quality of life in informal settlements in south africa. soc indic res 2007;81(2):375-388. 13. background information for the ppt pilots project in southern africa. available at: http://www.pptpilot.org.za/alexandra_township.pdf. accessed august 27, 2009. 14. van mechelen w, van lier wh, hlobil h, crolla i, kemper hcg. eurofit: handleiding met referentieschalen voor 12tot en met 16-jarige jongens en meisjes in nederland. haarlem: uitgeverij de vrieseborch; 1991. 15. armstrong meg. youth fitness testing in south african primary school children: national normative data, fitness and fatness, and effects of socioeconomic status. phd thesis, university of cape town, june, 2009. 16. gittelsohn j, merkle a, story m, et al. school climate and implementation of the pathways study. prev med 2003;37(6 pt 2):s97-s106. 17. morgan pj, hansen v. classroom teachers’ perceptions of the impact of barriers to teaching physical education on the quality of physical education programs. res q exercise sport 2008;79(4):506-516. 18. carrel al, mcvean jj, clark rr, peterson se, eickoff jc, allen db. school-based exercise improves fitness, body composition, insulin sensitivity, and markers of inflammation in non-obese children. j pediatr endocrinol metab 2009;22(5):409-415. 19. christodoulos ad, douda ht, polykratis m, tokmakidis sp. attitudes towards exercise and physical activity behaviours in greek schoolchildren after a year long health education intervention. br j sports med 2006;40(4):367-371. 20. caballero b, clay t, davis sm, et al. pathways: a school-based, randomized controlled trial for the prevention of obesity in american indian schoolchildren. am j clin nutr 2003;78(5):1030-1038. 52 sajsm vol 19 no. 3 2007 introduction field hockey and soccer have both been described as multiple sprint sports 5 consisting of high-intensity sprints that require short bursts of near maximal effort lasting between 5 and 10 seconds. 11,14,25 match play analysis of competitive soccer has shown that high-intensity efforts occur approximately every 30 seconds for each player, 17 and that the motion activities for elite hockey and soccer players are considered to be similar. 23 therefore, many exercise scientists and coaches have used the same type of field tests for hockey and soccer for the purposes of talent identification and training prescription. 8,12,17,20 however, the validity of doing this is unknown as data comparing the physical attributes of soccer and hockey players are lacking. the anthropometric and physiological characteristics of elite male soccer players have been well researched and documented. 4,16,18-20 a database of the physical norms for elite male hockey players was established in 1991. 21 however, since then there have been numerous rule changes in the game and substantial improvements in equipment with the effect of transforming hockey into a faster, more physical and highly technical sport. 2 although some research has addressed the game of hockey since these rule changes, 3,11 the main focus of research has been directed at elite female hockey players. 2,26 as a result there is a lack of recent research on the physiological characteristics of elite male hockey players, which makes comparison with soccer players difficult. therefore, the aim of this study was to establish the physical characteristics of elite south african male hockey and soccer players. the next step was to determine whether the physical characteristics of the hockey and soccer players original research article physical profiles of elite male field hockey and soccer players – application to sport-specific tests abstract background. the physical demands of field hockey and soccer, based on match analysis, are comparable. as a consequence many exercise scientists and coaches have started to use the same type of field tests for hockey and soccer for the purposes of talent identification and training prescription. the validity of this practice is unknown and the data supporting the similarity of the physical attributes of soccer and hockey players are lacking. objectives. to compare the physical attributes of elite south african hockey and soccer players. methods. elite hockey players (n=39: 22±3 years; mean ± standard deviation) and soccer players (n=37; 24±4 years) completed a set of physical tests including a 10 m and 40 m sprint test, a repeated sprint test (sprint fatigue resistance), a 1rm bench press and a push-up test. results. there were no differences in the 10 m (1.8±0.1 s both groups) and 40 m (5.4±0.2 s v. 5.3±0.2 s; hockey v. soccer) sprint times and distance run in the repeated sprint test (754±14 m v. 734±51 m). the hockey players were stronger (82±16 v. 65±13 kg) and did more push-ups (49±12 v. 38±10 push-ups) than the soccer players. conclusions. it is acceptable to use the same type of sport-specific tests to measure sprint capacity and sprint correspondence: justin durandt discovery health high performance centre private bag x5 sport science institute of south africa newlands 7725 tel: 021-659-5640 fax: 021-659-5601 e-mail: jdurandt@ssisa.co.za justin j durandt, bsc (med) hons exercise science (biokinetics))1 juliet p evans, bsc (med) hons exercise science)2 paul revington (ba)3 allan temple-jones (ba sports science, hons biokinetics)1 robert p lamberts (msc exercise science/ human movement science, bsc in physiotherapy (pt))2 1 discovery health high performance centre, sport science institute of south africa, newlands 2 mrc/uct research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, sport science institute of south africa, newlands 3 sa hockey association, valerie crescent, orange grove, johannesburg fatigue resistance for hockey and soccer players. however, it is questionable whether the normative data derived for upper body strength for soccer players are relevant for hockey players, and vice versa. sajsm vol 19 no. 3 2007 53 were sufficiently similar to justify using the same sport-specific tests for talent identification and training prescription. materials and methods subjects thirty-nine elite male field hockey players and 37 soccer players, all playing in their highest respective national leagues, were used in this study. all subjects were tested between 2003 and 2005 at the high performance centre of the sports science institute of south africa. the study was approved by the ethics and research committee of the university of cape town. wherever possible all tests were completed on the same day in the same order as described below: 1. body composition 2. 10 m and 40 m speed 3. repeated sprint test 4. 1rm bench press 5. push ups. the subjects in both groups were divided into defending, midfield and attacker subgroups. 1. body composition body mass was recorded on a calibrated scale (seca model 708, seca, hamburg, germany) and recorded to the nearest 0.1 kg. the players were weighed in undergarments and without shoes. the stature of each player was recorded to the nearest mm using a stadiometer (seca model 708, seca germany). 2. 10 m and 40 m speed the warm-up before this test consisted of a minimum of 10 minutes of self-paced submaximal running, followed by an appropriate stretching regimen and some acceleration sprints for players to familiarise themselves with the intensity of the test. an electronic sprint timer with photo-electric sensors (newtest oy, oulu, finland) was set at chest height and placed at 10 m and 40 m intervals from the start line. the player was instructed to crouch in the start position, 30 cm from the start line, after which he sprinted maximally for 40 m through the sensors. the player completed two maximal effort runs separated by a recovery period of 5 10 minutes. players wore running shoes without spikes. the fastest 10 m and 40 m times for each player were recorded. the 90% confidence intervals of the typical error were calculated for both hockey and soccer players (a new view of statistics, www.sportsci.org). ten and 40 m sprint typical errors were calculated from players at the same level of performance. the 90% confidence intervals for the typical error in the 10 m sprint was very similar between the hockey (0.02 0.04 s) and soccer players (0.02 0.05 s) and is in accordance with other research. 7 in the 40 m sprint times the typical error was slightly higher in the soccer (0.08 0.16 s) compared with hockey players (0.04 0.06 s). 3. repeated sprint the repeat sprint test, which is used in this study, was the modified 5-m multiple shuttle test (5-m mst) as described by boddington et al. 2 each subject completed his own specific warm-up for a maximum period of 10 minutes. after this all subjects ran 2 submaximal repeats (125 m) of the 5-m mst which was used as their final warm-up and familiarisation of the protocol. the layout for the test consisted of 6 beacons which were placed 5 m apart in a straight line to cover a total distance of 25 m. each subject started the test in line with the first beacon, and upon an auditory signal sprinted 5 m to a second beacon, touched the ground adjacent to the beacon with their hand and returned back to the first beacon, touching down on the ground adjacent to the beacon with the hand again. the subject then sprinted 10 m to the third beacon, and back to the first beacon, etc. the player continued back and fourth until an exercise period of 30 seconds had elapsed. no instruction was given as to which hand should touch during each turn. subjects were instructed to avoid pacing and perform with a maximal effort throughout the whole test. the distance covered by each subject was approximated to the nearest 2.5 m during each 30-second shuttle. the subjects performed 6 repeat bouts of this protocol with a 35-second rest between bouts. the total distance covered in the 6 bouts was recorded. the 90% confidence intervals of the repeated sprint test were calculated from the data gathered by boddington et al., which is partially published 2 and was similar in soccer (7 19 m) and hockey players (11 20 m). 4. 1rm bench press the player lay supine on a bench with his feet flat on the floor and his hips and shoulders in contact with the bench. hand spacing was set at approximately 1.5 times the player’s biacromial breadth. the player started this test by lowering the bar in a controlled manner to the centre of the chest, touching the chest lightly and then extending upwards until the arms were in a fully locked position. a light warm-up set of 10 repetitions was performed using a 20 kg weight. this was followed by 6 8 repetitions at approximately 30 40% of the estimated 1rm, which was based on previous resistance training experience. a 2-minute stretching routine for the shoulders and chest was completed, followed by a further 6 repetitions on the bench press at a weight corresponding to 60% of the estimated 1rm. the player then rested for 3 4 minutes before attempting his 1rm. if the 1rm was successful, the player had a 5-minute rest before attempting a bench press using a resistance that had been increased by 2.5% to 5.0%. if the player could not lift the weight the previous successful weight lifted was recorded as his 1rm. the test was scored as the maximum amount of weight (kg) that could be lifted with one repetition. a lift was disqualified if the player lifted his buttocks during the movement, bounced the bar off his chest, extended his arms unevenly, or if the bar was touched by the spotter. 1rm absolute bench press was recorded in kilograms (kg), and the 1rm relative bench press was calculated as 1rm/ (bodyweight 0.57 ). 6 no data could be found concerning typical errors in bench press. 54 sajsm vol 19 no. 3 2007 5. push ups the player began in a prone position with his hands on the floor, thumbs shoulder width apart and elbows fully extended. keeping the back and body straight, the player descended to the tester’s fist, placed on the floor below the player’s sternum, and then ascended until the elbows were fully extended. if the player did not adhere to these specifications the repetition was not counted. the test was scored as the number of push ups performed in 1 minute. no data could be found concerning typical errors in push-ups. statistics the data were analysed with statistica (statsoft, inc. (2004). statistica (data analysis software system), version 7. www.statsoft.com.). values are expressed as mean ± standard deviation. the data of the hockey and soccer players were compared using a two-way analysis of variance. statistical significance was accepted at p<0.05. a tukey post-hoc analysis was used when there was a significant difference between sport (soccer or hockey) and playing position (attackers, midfielders or defenders). results the general descriptive characteristics of the hockey and soccer players are summarised in table i. hockey players were significantly taller (f=6.1; p=0.016) and younger (f=9.3 p=0.003) compared with the soccer players. no differences were found between the two sports for body weight and body mass index (bmi). the 10 m and 40 m sprint times and distance run in the repeat sprint test (5-m mst) were similar for hockey and soccer players (table ii). however, a significant difference was found between the two sports in their 1rm bench test performance (f=24.1; p<0.001). the 1rm bench press of the hockey players was 21% higher than that of the soccer players (82±16 v. 65±13 kg, respectively). even when the 1rm values were corrected for bodyweight6 hockey play ers were significantly stronger than soccer players (f=29.6; p<0.001). an interaction effect (sport x position) was found for the push ups (f =9.4; p<0.001). further analysis revealed that hockey midfielders and defenders were able to do more push-ups compared with the soccer players playing in these same positions (p<0.001 and p=0.009, respectively). no dif ferences were found between the hockey and soccer attack ers (p=0.92). discussion the first finding of this study was that the mean height and age of the hockey and soccer players were significantly dif ferent. however, they only differed by 2 cm and 2 years re spectively and therefore it is unlikely that there is any practi cal relevance in these differences as these values fall within table ii. time(s) for 10 m and 40 m sprint, repeated sprint test (m), bench press (kg) (absolute and relative) and number of push-ups of soccer and hockey attackers, midfielders and defenders (mean ± standard deviation) hockey soccer attackers midfielders defenders total attackers midfielders defenders total (n=11) (n=13) (n=15) (n=39) (n=8) (n=15) (n=14) (n=37) 10m sprint (s) 1.78±0.09 1.80±0.07 1.81±0.10 1.8±0.1 1.72±0.09 1.81±0.13 1.73±0.09 1.8±0.1 40m sprint (s) 5.29±0.17 5.39±0.13 5.48±0.30 5.4±0.2 5.27±0.15 5.38±0.25 5.27±0.19 5.3±0.2 repeat sprint (m) 730±102 778±17 750±48 754±64 748±18 744±32 714±75 734±51 push-ups 42±9 57±11 + 49±11 ‡ 49±12* 46±10 35±11 + 35±7 ‡ 38±10* 1rm bench (kg) 83±15 80±16 84±17 82±16* 66±10 62±13 69±14 65±13* 1rm/body mass 0.57 7.0±1.1 7.0±1.2 7.1±1.2 7.0±1.1* 5.9±0.9 5.5±0.9 5.6±1.0 5.6±0.9* * p<0.001 + p<0.001 hockey midfielders v. soccer midfielders ‡ p= 0.009 hockey defenders v. soccer defenders table i. general descriptive characteristics of the field hockey and soccer players (mean ± standard deviation) hockey soccer attackers midfielders defenders total attackers midfielders defenders total (n=11) (n=13) (n=15) (n =39) (n=8) (n=15) (n=14) (n=37) age (yrs) 20±2 22±3 22±3 22±3 * 26±4 23±3 25±5 24±4* height (cm) 179±3 177±7 179±7 178±6 * 170±6 175±6 179±7 176±7* weight (kg) 76±6 73±7 77±15 75±9 69±5 70±8 79±8 73±9 bmi (kg.m 2 ) 24±3 23±2 24±2 23±2 24±1 23±2 25±2 24±2 * p<0.05 sajsm vol 19 no. 3 2007 snormal ranges for elite sportsmen playing at this level, as shown in previous studies on hockey 21 and soccer 1,9 players. the next finding was that the sprint times and repeated sprint distances between elite hockey and soccer players were similar. this supports the findings of previous research on match analysis, which have shown that the motion activities of elite male hockey and soccer players are comparable. 17,23 therefore, from this context of exercise testing and prescription it is reasonable to assume that the same type of tests can be used in soccer and hockey to measure sprint capability and fatigue resistance. although this is already generally accepted and recommended by many researchers 8,13,15,24 this is the first paper to show that the sprint times and fatigue resistance of elite soccer and hockey players are indeed similar. the third finding was that upper body strength and endurance, as measured by 1rm bench press and push-ups respectively, were significantly higher in the hockey players (bench press absolute: 21%; bench press relative: 20% and push-ups: 22% higher in hockey players compared with soccer players). one explanation for the hockey players having a stronger upper body is that the demands of the game require them to wield a stick as part of the game. another explanation is that the soccer players in this study were not particularly strong. this interpretation is supported by research on two elite norwegian soccer teams which showed 1rm bench press values of 77±17 (n=15) and 83±13 kg (n=14). 27 these values are comparable with the results that we found in our field hockey players, suggesting that the soccer players in our study were particularly weak. this interpretation will have to be confirmed by further analysis of data of players from different countries. previous research focusing on talent identification in soccer has emphasised the relevance of upper body strength in soccer for coping with physical aspects of the game and for throwing in, 10,22 lending support to the explanation that the soccer players in this study underperformed in the tests of upper body strength. until recently there has not been much emphasis on upper body conditioning in soccer players in south africa as there has been a perception that resistance training will increase the weight of players and therefore decrease their speed (high performance centre: personal observation). in contrast, the structures governing hockey in south africa have launched national high-performance programmes which have included upper body training programmes and minimum requirements of fitness. in conclusion, this paper shows that it is acceptable to use the same type of sport-specific tests and normative data to measure sprint capacity and sprint fatigue resistance for hockey and soccer players. for the measurement of upper body strength the same type of test can be used although it is questionable whether the normative data derived for soccer players are relevant for hockey players, and vice versa. acknowlegdements the study was funded by discovery health, university of cape town research unit for exercise science and sports medicine, medical research council of south africa and the harry crossley and nellie atkinson research funds. references 1. bloomfield j, polman r, butterly r, o’donoghue p. analysis of age, stature, body mass, bmi and quality of elite soccer players from 4 european leagues. j sports med phys fitness 2005; 45: 58-67. 2. boddington mk, lambert mi, st clair gibson a, noakes td. reliability of a 5-m multiple shuttle test. j sports sci 2001; 19: 223-8. 3. boyle pm, mahoney ca, wallace wf. the competitive demands of elite male field hockey. j sports med phys fitness 1994; 34: 235-41. 4. chamari k, hachana y, ahmed yb, et al. field and laboratory testing in young elite soccer players. br j sports med 2004; 38: 191-6. 5. dawson b, fitzsimons m, ward d. the relationship of repeated sprint ability to aerobic power and performance measures of anaerobic work capacity and power. aust j sci med sport 1993; 88-93. 6. dooman cs, vanderburgh pm. allometric modeling of the bench press and squat: who is the strongest regardless of body mass? j strength cond res 2000; 14: 32-6. 7. duthie gm, pyne db, ross aa, livingstone sg, hooper sl. the reliabil ity of ten-meter sprint time using different starting techniques. j strength cond res 2006; 20: 246-51. 8. elferink-gemser mt, visscher c, lemmink ka, mulder tw. relation be tween multidimensional performance characteristics and level of perform ance in talented youth field hockey players. j sports sci 2004; 22: 1053 63. 9. eniseler n. heart rate and blood lactate concentrations as predictors of physiological load on elite soccer players during various soccer training activities. j strength cond res 2005; 19: 799-804. 10. hoff j. training and testing physical capacities for elite soccer players. j sports sci 2005; 23: 573-82. 11. lakomy j, haydon dt. the effects of enforced, rapid deceleration on per formance in a multiple sprint test. j strength cond res 2004; 18: 579-83. 12. lemmink ka, verheijen r, visscher c. the discriminative power of the interval shuttle run test and the maximal multistage shuttle run test for playing level of soccer. j sports med phys fitness 2004; 44: 233-9. 13. lemmink ka, visscher c, lambert mi, lamberts rp. the interval shuttle run test for intermittent sport players: evaluation of reliability. j strength cond res 2004; 18: 821-7. 14. mayhew s, wenger h. time-motion analysis of professional soccer. jour nal of human movement studies 1985; 11: 49-52. 15. nicholas cw, nuttall fe, williams c. the loughborough intermittent shut tle test: a field test that simulates the activity pattern of soccer. j sports sci 2000; 18: 97-104. 16. reilly t, bangsbo j, franks a. anthropometric and physiological predispo sitions for elite soccer. j sports sci 2000; 18: 669-83. 17. reilly t, borrie a. physiology applied to field hockey. sports med 1992; 14: 10-26. 18. reilly t, doran d. science and gaelic football: a review. j sports sci 2001; 19: 181-93. 19. reilly t, gilbourne d. science and football: a review of applied research in the football codes. j sports sci 2003; 21: 693-705. 20. reilly t, williams am, nevill a, franks a. a multidisciplinary approach to talent identification in soccer. j sports sci 2000; 18: 695-702. 21. scott pa. morphological characteristics of elite male field hockey players. j sports med phys fitness 1991; 31: 57-61. 22. shephard rj. biology and medicine of soccer: an update. j sports sci 1999; 17: 757-86. 23. spencer m, lawrence s, rechichi c, bishop d, dawson b, goodman c. time-motion analysis of elite field hockey, with special reference to re peated-sprint activity. j sports sci 2004; 22: 843-50. 24. sunderland c, nevill me. high-intensity intermittent running and field hock ey skill performance in the heat. j sports sci 2005; 23: 531-40. 25. tumilty d. physiological characteristics of elite soccer players. sports med 1993; 16: 80-96. 26. wassmer dj, mookerjee s. a descriptive profile of elite u.s. women’s col legiate field hockey players. j sports med phys fitness 2002; 42: 165-71. 27. wisloff u, helgerud j, hoff j. strength and endurance of elite soccer play ers. med sci sports exerc 1998; 30: 462-7. 55 44 sajsm vol 22 no. 2 2010 introduction episodic or recurrent events are a class of data that is frequently described in sports medicine literature. however, the correct statistical techniques to deal with data containing recurrent events are not widely known within sports medicine and the exercise sciences. this is evidenced by the few papers in these specialist sciences that discuss the use of appropriate statistical techniques1,2 and the preponderance of papers assuming event independence for recurrent events. for instance, in a recent paper3 it is apparent that there is a trend in studies reporting injury incidences in rugby union players that need to be highlighted, namely the use of naïve statistical methods that treat recurrent events as independent observations. a number of references are cited (see3 ref. 2, 11, 15-17) that also report injury incidence statistics in rugby union players, and as far as can be ascertained, treat recurrent or multiple injuries within the same individual as independent events. the purpose of this paper was first, on the basis of an example from the sports medicine literature, to contrast the effect of recurrent events on confidence intervals generated with unadjusted and adjusted univariate statistical techniques. second, to demonstrate the implementation of a multivariate regression technique on data containing recurrent data and confounding variables, using data from the exercise sciences. third, the use of two disparate examples should dispel the notion that the statistical techniques highlighted in this paper have limited application. statistical concepts and considerations for the purposes of this paper it is important to note that whether the injury occurs in the same or different anatomical structure does not influence how the event is considered in statistical terms; it is a recurrent event within the same individual. consequently, even if the unit of analysis or outcome of interest is the injury count, the injury counts are clustered around the individual player. injuries that occur in the same individual but at different anatomical sites can be correlated either through the mechanism of injury or via a common risk factor(s) to which the individual is exposed. clustering can also occur at group level, for example school or team.2 importantly, whether clustering occurs at individual or group level, and the data are continuous, binary or count, appropriate univariate, non-model-based (e.g. t-test) and multivariate, model-based (e.g. regression) techniques are available that correct for clustered or correlated data.2,4,5 appropriate multivariate techniques adjust not only for confounders, but also for event dependence.5 moreover, for injuries at different anatomical sites in the same individual, a categorical variable can be created by grouping the different anatomical sites so that the risk for injury at different anatomical sites can be assessed adjusting for confounders and event dependence.5 whether the investigator has used univariate or multivariate statistical methods, it is essential to use appropriate formulae and statistical techniques to account for the increased variance that these recurrent events will have on the standard error and thus the confidence intervals (ci) of point estimates such as incidence rates (ir) and incidence rate ratios (irr). not doing so will result in artificially narrow ci. if investigators are using the non-overlap of 95%ci to infer significant differences between ir, the adjustment for increased variance due to recurrent events is critical to avoid type i errors. constructing adjusted 95%ci for univariate age-specific or ageadjusted rates can be implemented in a spreadsheet,6 although it is recommended that suitable multivariate statistical techniques are invoked when analysing data sets with recurrent events.1,2,512 naïve statistical techniques either treat recurrent events as uncorrelated, or to avoid recurrent events only use the first event and ignore the subsequent events. in the former case, the ci are artificially narrow, in the latter case much information is lost. appropriate statistical techniques include generalised estimating equations, survival analysis (cox proportional hazards regression with robust variance estimation) and regression for count outcomes data (poisson or negative binomial models with robust variance estimation).13 statistical software packages such as sas, spss and stata are required to implement these multivariate techniques. importantly, the robust variance estimation yields irr with unbiased 95%ci. moreover, these are multivariate techniques which allow for the adjustment of relevant covariates and determination of risk for sub-groups. which multivariate technique to use will also be influenced by aspects such as whether the events are short or long lasting, analysing recurrent events in exercise science and sports medicine abstract episodic or recurrent events are a class of data that is frequently reported in health sciences research. the purpose of this paper is to highlight the prevalence of published reports, especially within the south african context, that have used inappropriate statistical techniques when dealing with episodic events and to urge the use of appropriate univariate and multivariate techniques. correspondence: ian cook physical activity epidemiology laboratory university of limpopo (turfloop campus) po box 459 fauna park 0787 polokwane south africa tel+fax: +27 15 268 2390 e-mail: ianc@ul.ac.za ian cook (ba (phys ed) hons, bsc (med) hons) physical activity epidemiology laboratory, university of limpopo (turfloop campus), polokwane commentary sajsm vol 22 no. 2 2010 45 and whether the events occur at predefined intervals (recurring treatments in randomised controlled trials), or on a continuous basis (injuries or hospitalisation).9 also, data structure requirements can differ between techniques – multiple rows per person or one row per person.9 if the recurrent events display event dependence (subsequent events are more or less likely to occur) and there is heterogeneity across individuals (cases with higher or lower event rates due to unaccounted for effects) then more complex models are required and statistical advice should be sought.12 the present discussion does not suggest that univariate techniques must be abandoned because statistical corrections are available for dealing with recurrent events and confounding.2,5 what is being advocated in this paper is that researchers should consider the use of multivariate techniques which are more efficient than univariate techniques for datasets containing recurrent events and confounding variables.5 hence, statistical power is increased when using appropriate multivariate techniques in the presence of event recurrence and confounding. practical applications example 1: sports medicine it would appear from the methodological descriptions in viljoen et al. 3 and the studies that they cited that univariate statistical techniques, which assume group independence,14 were used to compare ir across two or more years or between training and match play (chisquare test for trend, z-test), and to construct crude ir 95%ci. in so doing, these studies have likely violated the statistical principle of independence of events to a greater or lesser degree, depending on the number of recurrent events. it is evident from table i in their paper that there are recurrent events not only in the persistent injuries but also in the new injuries.3 for example, from 38 injuries and 300 person-hours accumulated in the 2002 season (table ii),3 the crude ir 95%ci is reported as 126.7 injuries per 1 000 personhours (91.2 169.7 injuries per 1 000 person-hours). however, using standard statistical software (stata/se 11.0 for windows, statacorp lp, texas, usa, 2009), the poisson exact or fisher’s exact 95%ci is 89.6 173.9 injuries per 1 000 person-hours. if one assumes the new injuries (n=38) are evenly distributed in the 19 injured players during the 2002 period (table ii),3 then there are 2 injuries per player. once the increased variance has been taken into account, the crude ir 95%ci widens to 71.5 181.9 injuries per 1 000 person-hours (ideally the method employed here should be used for n>50).6 assuming that of the 19 injured players, 5 players have 3 injuries, 5 players have 1 injury and the remaining 9 players have 2 injuries each, the crude ir 95%ci widens even further; 67.7 185.6 injuries per 1 000 person-hours. it is evident that increasing recurrences have significant effects on the ci. example 2: exercise science unpublished minute-by-minute, uni-axial accelerometry data (1 7 days) were collected in 263 rural and 16 urban women. the variable of interest was the number of bouts of ≥10 min of continuous moderate-to-vigorous activity the women accumulated (≥1 952 counts. min-1). the question was whether urban women have greater odds of accumulating bouts of moderate-to-vigorous activity compared with rural women. crude ir for the rural and urban women were 22.8 bouts per 1 000 person-hours and 31.9 bouts per 1 000 personhours, respectively, and 170 women recorded more than one bout of moderate-to-vigorous activity. using standard methods, which assume event independence, for calculating exact poisson ir 95%ci yielded 21.2 24.4 bouts per 1 000 person-hours and 24.3 41.2 bouts per 1 000 person-hours, for rural and urban women respectively. correcting for the increased variance due to episodic events by univariate means,6 the ir for rural and urban women widened to 18.7 26.8 bouts per 1 000 person-hours and 8.3 55.5 bouts per 1 000 person-hours, respectively. a simple poisson regression model, treating all the events as independent, produced an irr of 1.40 (p=0.012, 95%ci: 1.08 1.83). on the basis of this superficial analysis we would conclude that urban women are significantly more likely (1.4-fold) to accumulate continuous bouts of moderate-to-vigorous activity, compared with rural women. however, by accounting for the recurrent events within individuals, the point estimate was no longer significant (irr=1.40, p=0.281, 95%ci: 0.76 2.59). by extending the analysis and adding age, body mass index and subsistence level as covariates, while retaining the robust variance estimation option, the irr increased to 1.80 (p=0.042, 95%ci: 1.02 3.16). we can now report that all reasonable analyses have been conducted on the dataset and can conclude that urban women are statistically more likely to accumulate bouts of continuous moderate-to-vigorous activity compared with rural women, adjusting for covariates. summary investigators reporting data which include recurrent events are urged to employ appropriate univariate and multivariate statistical techniques. ignoring the valid methods available1,2,5-12 can lead to conclusions being drawn which are at odds with the data.9 moreover, south african injury incidence data that have been analysed and reported, using naïve statistical methods, could be re-analysed using these univariate and multivariate statistical techniques and provide a more thorough understanding of the associated risks. references 1. knowles sb, marshall sw, guskiewicz km. issues in estimating risks and rates in sports injury research. j athl train 2006;41:207-215. 2. hayen a. clustered data in sports research. j sci med sport 2006;9:165168. 3. viljoen w, saunders cj, hechter gd, aginsky kd, millson hb. training volume and injury incidence in a professional rugby union team. s afr j sports med 2009;21:97-101. 4. ying g, liu c. statistical analysis of clustered data using sas system. available at: http://nesug.org/proceedings/nesug06/an/da01.pdf. accessed july 2010. 5. glynn rj, buring je. ways of measuring rates of recurrent events. bmj 1996;312:364-367. 6. stukel ta, glynn rj, fisher es, sharp sm, lu-yao g, wennberg je. standardized rates of recurrent outcomes. stat med 1994;13:17811791. 7. kuramoto l, sobolev b, donaldson m. on reporting results from randomized controlled trials with recurrent events. bmc med res methodol 2008;8:35. 8. sturmer t, glynn rj, kliebsch u, brenner h. analytic strategies for recurrent events in epidemiologic studies: background and application to hospitalization risk in the elderly. j clin epidemiol 2000;53:57-64. 9. twisk jwr, smidt n, de vente w. applied analysis of recurrent events: a practical overview. j epidemiol comm health 2005;59:706-710. 10. thomsen jl, parner et. methods for analysing recurrent events in health care data. examples from admissions in ebeltoft health promotion project. fam pract 2006;23:407-413. 11. gill dp, zou gy, jones gr, speechley m. comparison of regression models for the analysis of fall risk factors in older veterans. ann epidemiol 2009;19:523-530. 12. box-steffensmeier jm, de boef s. repeated events survival models: the conditional frailty model. stat med 2006;25:3518-3533. 13. juul s. an introduction to stata for health researchers. 2nd ed. texas: stata press, 2008. 14. armitage p, berry g, matthews jns. statistical methods in medical research. 4th ed. massachusetts: blackwell publishing, 2002. original research sajsm vol 23 no. 4 2011 117 introduction high blood pressure (hypertension) is the greatest risk factor for cardiovascular disease, 1 which is responsible for up to 7 million deaths worldwide every year. 2 the centres for disease control and prevention (cdc) indicates that 1 in 3 adults in america have hypertension 3 and the same trend is found in south africa, where 55% of adults 30 years and older have hypertension. 4 until recently, hypertension was a rare phenomenon amongst children, possibly due to fewer environmental stressors, higher physical activity levels, a lower prevalence of obesity and a healthier lifestyle. 5 chiolero et al. 6 are of the opinion that the worldwide increase in obesity amongst children over the last two decades probably resulted in an increase in the incidence of hypertension in children. 6 in this respect, munter et al. 7 found that the systolic and diastolic bp of children were respectively 1.4 mmhg and 3.3 mmhg higher in 1999 2000 than in 1988 1994 and attribute this increase in hypertension largely to the increased incidence of overweight children. whitney and rolfes 8 report that obesity contributes to the development of hypertension because additional adipose tissue contains extra capillaries through which the blood has to pump and, consequently, puts extra strain on the heart and veins, which results in increased bp. a south african study on 5-year-old children indicated that 11.6% of these children suffered from hypertension, 9 while the study of monyeki et al. 10 conducted on 6 13-year-old children from rural communities revealed that 1.0 5.8% of the boys and 3.1 11.4% of the girls had hypertension. in this study there was a direct association between the prevalence of hypertension amongst the children from rural communities and an increased body mass index (bmi). 10 research evidence indicates that even a moderate increase in bp could have a negative effect on the vascular structure and function of children. 11 children with increased bp could develop target organ damage and retinal abnormalities. 12 furthermore, such children are also more at risk of hypertension-related illnesses in their adult lives. 13 overweight and obesity have increased drastically in children over the last 2 decades. 14 the phenomenon has occurred throughout the world, including in south africa, and is regarded as a serious health problem as it could have an effect on current and future public health. 15 statistics in south africa indicate that in children between the ages of 6 and 13 years, 14.0% and 3.2% of boys are overweight and obese respectively, compared to 17.9% and 4.9% of girls (overweight and obese). 16 sorof et al. 17 further report that hypertension occurs in 33% of children who are obese compared with 11% in those children who are not obese. various studies also show that overweight children display higher systolic bp than children of normal weight. 5,18 a study abstract objective. to determine the prevalence of hypertension in grade 1 learners in the north west province of south africa and to investigate the association between blood pressure (bp) and body composition of these children. methods. data were collected by means of a stratified random sampling procedure from 816 grade 1 learners (419 boys, 397 girls) with a mean age of 6.78±0.49 years (mean±sd), in the nwchild-study. height, weight, skinfolds (subscapular, triceps, calf) and waist circumference were measured. the international recommended cut-off values of cole et al. (2000) for body mass index (bmi) were used. hypertension, defined as the average of two separate bp (bp) readings, where the systolic bp and diastolic bp is >95th percentile for age, sex and height, was determined by means of an omron 705cp-ii. results. the overall prevalence of prehypertension and hypertension was 8.5% and 24.9%, respectively. both systolic and diastolic bp was positively associated with bmi, body fat percentage and waist circumference. boys and girls showed a similar prevalence of hypertension. a higher percentage of black children were hypertensive compared with whites, although the difference in bp of the groups was not significant. a high percentage of children with normal weight also showed increased levels of bp. conclusions. high prevalences of hypertension were found in grade 1 learners in the north west province of south africa. small practical significant associations existed between bp and body composition. bp screening is therefore considered important in the paediatric population. interventions which include physical activity are recommended to reduce potential cardiovascular complications and obesity among children. other contributing factors to high bp amongst young children should also be investigated. chanelle kemp1 (msc) anita e pienaar1 (phd) aletta e schutte2 (phd) 1 school for biokinetics, recreation and sports science in the nicharea phasrec 2 hypertension in africa research team (hart) north-west university (potchefstroom campus), potchefstroom, south africa correspondence to: ae pienaar (anita.pienaar@nwu.ac.za) the prevalence of hypertension and the relationship with body composition in grade 1 learners in the north west province of south africa 118 sajsm vol 23 no. 4 2011 of 6 13-year-old south african children indicated that there is a positive correlation between the bmi and bp of the children, even after adjustments have been made for age, gender and height. 19 the results of this study, however, are only based on children from disadvantaged communities. research indicates an increase in child obesity in south africa and this could possibly contribute to an increased prevalence of hypertension amongst children in south africa. 20 because of the potential health risks of hypertension, action needs to be taken to address this incidence. however, to develop adequate preventive strategies, it is important to determine the relationship between bp and body composition in south african children. in particular there is a gap in the literature with regard to this relationship within the diverse population of south africa, and especially the young child population. only a few studies could be found that examined the relationship of hypertension with overweight in south african child populations, 10,19 and the studies were mainly relevant to children of disadvantaged communities. hence, the aim of this study was to determine the prevalence of hypertension in grade 1 learners and, more specifically, to determine the relationship between the bp and body composition of grade 1 learners in the north west province. methods research group the research formed part of the nw-child (child-health-integrated-learning and development) study. grade 1 learners in the north west province of south africa served as the target population for the study. the total number of participants identified for the study was 880 grade 1 learners. the research group was selected by means of a stratified random sample in conjunction with the statistical consultation service of the north west university. to determine the research group, a list of names of schools in the north west province was obtained from the department of education. from the list of schools in the north west province, which are grouped in 4 education districts, each representing 12 22 regions with approximately 20 schools (minimum 12, maximum 47) per region, regions and schools were randomly selected with regard to population density and school status (quintile 1, i.e. schools from poor economic sectors to quintile 5, i.e. schools from good economic sectors). boys and girls in grade 1 were then randomly selected from each school. twenty schools, from 4 districts with a minimum of 40 children per school and with an even gender distribution, were involved in the study. the total group that was measured consisted of 816 learners (419 boys and 397 girls) with an average age of 6.78 years and an ethnic distribution of 567 black, 218 white, 20 coloured and 11 indian learners. thirteen parents (1.5%) did not consent to participation, while the rest of the selected participants were absent at school on the day of testing or had to be excluded because of incorrect ages that were provided by the schools. the principals of the various identified schools were asked for permission to collect the data during school hours. if the numbers of learners in the school allowed it, 60 grade 1 learners were randomly selected and received informed consent forms that had to be completed by their parents. this was done to ensure that informed consent would be granted by the parents of a minimum of 40 learners who needed to be measured at each school. the learners whose parents reacted positively to the above-mentioned forms, underwent the tests. ethical approval for the execution of the study was obtained from the ethics committee of the nwu (no. nw 00070 09 s1). permission was also obtained from the education department of the north west province. anthropometric measurements the anthropometric measurements included the following: height (cm), body mass (kg), 3 skinfolds (subscapular, triceps and medial calf) (mm) and waist circumference (cm). these variables measured were measured by trained postgraduate students in kinderkinetics in accordance with the protocol of the international society for the advancement of kinantropometry. 21 height was measured barefoot to the nearest 0.1 cm by means of a portable stadiometer, and body mass was measured with an electronic scale (bf 511, omron) to the nearest 0.1 kg. from the height and body mass measurement the body mass index (bmi) was calculated for each participant. skinfolds were measured with a pair of harpenden skinfold callipers and each skinfold was measured twice to obtain the average of the two measurements. these skinfold measurements were selected because, according to meredith and welk, 22 they show the highest correlation with the overall percentage of fat in the bodies of children. because the bmi of children changes continually as they get older, cole and co-workers 23 determined age-specific bmi cut-off values to identify obesity in growing children and these were used to categorise the participants into a normal weight, overweight or obese group. the cut-off values for 6-year-old overweight and obese children are >17.34 kg/m 2 and >19.65 kg/m 2 , while for 7-year-old children they are >17.75 kg/m 2 and >20.51 kg/m 2 , respectively. 23 waist circumference, which was measured at the narrowest point between the lower costal (10th rib) border and the crista iliaca, was measured in the standing position with a standard measuring tape (0.1 mm intervals). blood pressure bp was measured with an omron 705cp-ii, (kyoto, japan). the width of the cuff (small 17 22 cm, medium 22 32 cm, large 32 42 cm) was adapted to the arm width. bp was measured while the child was seated, with the left arm resting on a table top with the palm turned upwards. duplicate readings were recorded after the child had rested for 5 minutes. the mean of the two readings was used to determine the bp. normal bp is defined as systolic and/or diastolic bp less than the 90th percentile for age, gender and height according to the cut-off values of the national high bp education program working group (nhbpep) on high bp in children and adolescents; 24 prehypertension is defined as systolic and/or diastolic bp greater than or equal to the 90th percentile, but less than the 95th percentile and paediatric hypertension is defined as systolic and/or diastolic bp greater than or equal to the 95th bp percentile for age, gender and height. 24 statistical analyses statistica 25 was used to analyse the data. a proportionally stratified sample was drawn with regard to ethnicity by making use of the population constitution data from statistics south africa 26 to ensure that the data could be generalised to children in the north west province. for the purpose of description, data were analysed on the basis of means, maximum and minimum values and standard deviations (sd). data were also further analysed by making use of spearman correlation coefficients to analyse the relationship between bp and body composition. for the interpretation of practical significance, the following guidelines of cohen 27 concerning magnitude of effect were used, namely, d>0.1 indicates a small effect; d>0.3 indicates a moderate effect and d>0.5 indicates a large effect. in addition, use sajsm vol 23 no. 4 2011 119 was made of a one-way analysis of variance to determine significant differences between the groups (normal weight, overweight and obese), and logistic regression was used to determine trends with regards to prevalence of prehypertension and hypertension between the subgroups. because of the small number of coloured and indian children that entered the sample, these children were excluded from the analysis of race differences, although their data were considered in the other results. results table i displays the descriptive statistics of the research group. the table shows that 88.4% of the learners were in the normal weight category, 7.8% into the overweight category and 3.8% into the obese category. the table also shows that a smaller percentage of the boys in comparison with the girls were in the overweight (6.4% compared with 9.3%) and obese (3.3% compared with 4.3%) categories. a smaller percentage of the black learners in comparison with the white learners fell into the overweight (6.0% compared with 13.3%) and obese (2.8% compared with 6.4%) categories. table ii displays the percentage of learners of the total group, and race and gender separately, that can be classified with prehypertension and hypertension in the various bmi groups. a greater percentage of the research group were in the hypertension group compared with the prehypertension group. it appears that the prevalence of prehypertension may increase with an increase in bmi. the obese group displayed the highest prevalence of hypertension in comparison with the normal and overweight groups. boys showed a higher prevalence of prehypertension than the girls (9.8% compared with 6.8%), while the prevalence of hypertension in the boys and the girls was similar (24.8% compared with 24.9%). the prevalence of prehypertension was similar (8.7% compared with 8.3%), in the white and the black children, while black children displayed a higher prevalence of hypertension than the white children (25.9% compared with 21.6%). correlation coefficients were used to determine the relationship of systolic and diastolic bp with body composition (bmi, body fat percentage and waist circumference) of the participants. all the correlations were statistically and practically significant. systolic and diastolic bp had significant (p<0.01) positive correlations with bmi (r=0.22; r=0.18), body fat percentage (r=0.17; r=0.16) and waist circumference (r=0.21; r=0.19), although only with small practical significance (d-value>0.1). these correlations were further analysed by means of covariance of analysis in table iii where the mean values for the systolic and diastolic bp of the participants were analysed in the group in the 3 different bmi groups and also separately for gender and race. a t-test was used to make comparisons between gender and races and significant differences in this regard. these results are shown in the table with a#. table i. number and percentage of grade 1 learners according to classification in bmi-groups normal weight overweight obese total (n) (%) (n) (%) (n) (%) (n) group 721 88.4 64 7.8 31 3.8 816 boys 378 90.2 27 6.4 14 3.3 419 girls 343 86.4 37 9.3 17 4.3 397 white 175 80.3 29 13.3 14 6.4 218 black 517 91.2 34 6.0 16 2.8 567 n = number of participants. table ii. prevalence of prehypertension and hypertension amongst grade 1 learners according to bmi categories normal weight (n=721) overweight (n=64) obese (n=31) p for trend total (n) (%) (n) (%) (n) (%) (n) (%) prehypertension boys 34 9.0 4 14.8 3 21.4 0.15 41 9.8 girls 22 6.4 3 8.1 3 17.7 0.02 28 6.8 white 12 5.5 3 1.4 4 1.8 0.08 19 8.7 black 41 7.2 4 0.7 2 0.4 0.05 47 8.3 total group 56 7.8 7 10.9 6 19.4 0.008 69 8.5 hypertension boys 96 25.4 3 11.1 5 35.7 0.07 104 24.8 girls 82 23.9 11 29.7 6 35.3 0.14 99 24.9 white 40 18.3 4 1.8 3 1.4 0.004 47 21.6 black 130 22.9 10 1.8 7 1.2 0.47 147 25.9 total group 178 24.7 14 21.9 11 35.5 0.028 203 24.9 bmi = body mass index; n = number of participants; % = percentage; prehypertension >90th percentile <95th percentile; hypertension >95th percentile. 120 sajsm vol 23 no. 4 2011 due to the small number of coloured and indian children in the sample, these race groups were excluded from the analysis of race differences and only white and black children were compared. the systolic and diastolic mean bp values increased in the group as the bmi of the participants increased. the mean systolic and diastolic bp values of the normal weight and overweight children differed significantly from the obese children. differences between the groups are indicated with superscripts (a, b & c). boys in the normal weight group had significantly higher systolic bp values than the girls in this group. on the other hand, the girls in the obese group had higher systolic bp values in comparison with the boys in the obese group (not signifant) and the girls in the overweight and obese groups also had higher diastolic bp in comparison with the boys in the overweight and obese group (not significant). an analysis of possible race differences showed that there was a tendency for the diastolic bp values of black children to be higher than those of the white children in all 3 of the different bmi groups (not significant). discussion the aim of this study was to determine the prevalence of hypertension in grade 1 learners, as well as to determine the possible relationship between the bp and body composition of grade 1 learners in the north west province of south africa. our results regarding prehypertension in the group of 6 7-yearolds indicate a prevalence of 8.5%. this is similar to the findings of hansen et al., 28 who found a prevalence of 3.4% in a group of 3 18-year-old american children. with regards hypertension we showed a prevalence of 24.9%, which is a slightly higher than the 22.3% indicated in a study conducted by steyn et al. 9 more than 10 years ago in south africa. research demonstrates that the prevalence of hypertension has increased over the last decade as a result of the increase in overweight and obesity amongst children. 6 monyeki et al., 10 who focused on a relatively small group of black children (n=203) from disadvantaged communities, reported a 3.9% prevalence of hypertension in 6 7-year-old children. however, none of the 6 7-year-old children fell into the overweight category, which could also possibly contribute to the lower prevalence of hypertension that was reported in the study. the 35.5% prevalence of hypertension that was found in the obese group of children coincides with a study by sorof et al., 17 who reported a 33.0% prevalence of hypertension in obese children (11.8 years old). however, south africa lacks literature that reflects the prevalence of prehypertension and hypertension in 6 7-year-old children which could be used for comparison purposes. the results further showed that systolic and diastolic bp had a significantly positive correlation with bmi, body fat percentage and waist circumference, although the practical significance was small. these results concur with the study of monyeki et al. 10 on 6 13-year-old children in disadvantaged communities. waist circumference showed a positive and significant correlation with systolic and diastolic bp and coincides with research by cuestas et al. 29 on 2 9-year-old children. from the above-mentioned results it would appear that waist circumference could be used as a possible risk marker to identify children at risk of possible high bp. the obese children had significantly higher systolic and diastolic bp compared with the normal weight and overweight children and an increase in bmi was consequently associated with an increase in bp. these results coincide with studies conducted on children that table iii. mean bp of grade 1 learners according to bmi categories variables normal weight (a) (n=721) overweight (b) (n=64) obese (c) (n=31) mean sd 95%ci mean sd 95%ci mean sd 95%ci p for trend systolic bp (mmhg) total group (n=816) 96.8 c 14.0 (13.6;14.5) 99.3 c 11.1 (9.9;12.6) 106.1 ab 15.5 (13.2;18.7) <0.001 boys (n=419) 98.0 c 14.4 (13.8;15.1) 99.7 7.7 (6.4;9.7) 105.6 a 17.6 (14.0;23.5) 0.012 girls (n=397) 95.4 bc# 13.5 (12.9;14.2) 99.1 ac 12.6 (10.9;14.8) 106.6ab 13.5 (10.8;17.8) <0.001 white (n=218) 96.9 14.8 (13.4;16.5) 99.6 9.6 (7.6;13.0) 103.2 13.7 (9.9;22.1) 0.21 black (n=567) 96.9 c 14.0 (13.5;14.5) 99.4 11.7 (10.3;13.6) 106.1 a 15.8 (13.1;19.8) <0.001 diastolic bp (mmhg) total group (n=816) 64.6 c 13.1 (12.7;13.6) 67.0 c 11.2 (10.0;12.7) 72.0 ab 14.8 (12.6;17.9) <0.001 boys (n=419) 65.1 c 13.6 (13.0;14.2) 65.2 10.0 (8.3;12.5) 71.2 a 15.0 (12.0;20.0) 0.047 girls (n=397) 64. 0bc 12.6 (12.1;13.2) 68.0 a 11.8 (10.2;13.8) 72.8 a 14.8 (11.9;19.5) <0.001 white (n=218) 63.9 12.6 (11.4;14.1) 63.7 7.6 (6.1;10.3) 69.3 14.0 (10.2;22.6) 0.28 black (n=567) 64.6 c 13.2 (12.7;13.7) 68.2 12.1 (10.6;14.0) 72.8 a 15.3 (12.8;19.2) <0.001 bmi = body mass index; sd = standard deviation; a = normal weight; b = overweight; c = obese; mean with superscript differed significantly on a 5% level; # p-value <0.05 gender and race differences; ci = confidence interval. sajsm vol 23 no. 4 2011 121 found the same trends. 5,18 morphological and functional changes that probably occurred in these children, such as arterial stiffness and left ventricular hypertrophy, 30 carotid arterial wall thickening 31 and early activation of vascular endothelium and platelets 32 could be cited as possible reasons for this. all the changes associated with high bp that are reported in the literature indicate that the arteriosclerotic process already begins during the early childhood years. however, the results also show that a large percentage (24.7%, n=178) of the normal weight group (n=721) was also classified with hypertension. the high prevalence of hypertension in this group indicates that other factors, excluding body composition, may also play a role in the increased prevalence of hypertension. possible reasons that could be given for this include unhealthy dietary habits, such as a reduced intake of fruit and vegetables, a diet high in saturated fats and a high intake of salt. 33 these unhealthy dietary habits of high intake of salt often occur in the south african population, seeing that bread is the staple food of large numbers of this population and it contains high levels of sodium chloride. environmental stressors, such as violence and economic stressors, for example poverty, could possibly also have an influence on hypertension in children. 5 boys of the normal weight group had significantly higher systolic bp values than girls in the normal weight group. on the other hand, the girls in the obese group had higher systolic bp values compared with the boys in the obese group, although not statistically significant. girls in the overweight and obese group also displayed higher mean diastolic bp values compared with boys in the overweight and obese group, although also not statistically significant. these results correspond with research by agyemang et al. 34 and monyeki et al. 10 which also found that girls had higher bp than boys. a possible reason could be that girls have a higher percentage of fat than boys, which contributes to a higher prevalence of overweight and obesity and, as a result, they display higher systolic and diastolic bp values. as far as race differences are concerned, the mean diastolic bp values of the black children were higher than those of white children in all three of the different bmi groups, although not statistically significant. these results correspond with other research studies that also found that black children showed higher diastolic bp values than white children. 9,35,36 these studies, however, did not analyse the different bmi groups separately. furthermore, the results also show that the mean systolic bp of the black children was only higher than that of the white children in the obese group, although also not statistically significant. the studies of dekkers et al. 36 and cruz et al. 35 both show that the systolic bp of black children was higher than that of white children. the different bmi groups, however, were also not analysed separately in these studies. possible reasons that can be given for this are differences in socio-economic status, genetic, endocrine and environmental factors, as well as cardiac function, diet and stress. 37-39 seedat 37 further demonstrates that black hypertensive patients are more susceptible to cerebral bleeding and malignant hypertension, which is more inclined to give rise to congestive cardiac failure, while coronary cardiac diseases are less common. in contrast to this, coronary cardiac disease is the most important result of hypertension in the white community. these slight differences, although they can only be viewed as trends, could possibly indicate different causes of hypertension in the different race groups, and this speculation needs further research. the prevalence of hypertension, as well as prehypertension that was found in this study of 7-year-old children is disturbing, especially when considering the associated health-related problems. a notable relationship was also found between the bp and body composition in the overall group of children, although this relationship could be mediated by high hypertensive percentages that were also found in the normal weight group. bp during childhood is significantly associated with bp during adulthood. 6 therefore it is important to develop intervention programmes, especially those that are aimed at increasing levels of physical activity that would lead to weight loss in overweight and obese children and thus reduce the risk of hypertension. it is also advised that bp must be monitored from early childhood and that bp readings must be incorporated in the clinical evaluation of children on a routine basis so that possible cardiovascular risk factors can thus be monitored, especially in the case of overweight and obese children. this study, however, also shows that other factors besides body composition could have an effect on the prevalence of hypertension in children and follow-up studies are advised to obtain a better understanding of the influence of these factors. among others, growth retardation is a possible factor that could have an effect on the increased prevalence of hypertension, especially amongst children of normal weight, as height is taken into consideration in bp percentile tables. a shortcoming of the study was that, although two bp readings were taken five minutes apart, bp could only be taken once. however, most research studies conducted on children report this limitation. although everything was also done to set the participants at ease with regard to the nature of the bp reading, a child could have been erroneously classified as hypertensive as a result of anxiety. this study is, however, the beginning of a longitudinal study during which follow-up data will be collected on bp status in 2013 and 2016 and baseline bp will consequently be monitored in this way. it has, moreover, also been reported that health workers often underdiagnose hypertension in children as the values for children are not as precise as those for adults, but have to be recorded from bp percentile tables and these tables are not always available in health care clinics. 26 gender differences were indicated, but could not be analysed thoroughly in the race groups due to the limited numbers of children in the different race groups. in spite of these shortcomings, the study brought valuable information to the fore regarding the current prevalence of hypertension amongst grade 1 learners in the north west province of south africa and the effect of body composition, gender and race on the bp of these children. conclusion high prevalences of hypertension were found in grade 1 learners in the north west province of south africa. small practical significant associations existed between bp and body composition. screening for bp should therefore not be neglected in these children, especially within the black communities, where the prevalence of hypertension was higher than in the white children. we recommend that interventions, including physical activity, should be introduced to reduce potential cardiovascular complications and obesity among children. other factors contributing to high bp amongst children should also be investigated. references 1. vasan rs, larson mg, leip, et al. impact of high-normal blood pressure on the risk of cardiovascular disease. n engl j med 2001;345(18):12911297. 2. ezzati m, lopez, ad, rodgers a, vanderhoorn s, murray cj. comparative risk assessment collaborating group. selected major risk factors and global and regional burden of disease. lancet 2002;360:1347-1360. 122 sajsm vol 23 no. 4 2011 3. centers for disease control and prevention (cdc). high bp 2010 www.cdc 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2003;88(9):748-752. 16. armstrong meg, lambert mi, sharwood ka, lambert ev. obesity and overweight in south african primary school children – the health of the nation study. s afr med j 2006;96(5):439-444. 17. sorof jm, poffenbarger t, franco k, bernard l, portman rj. isolated systolic hypertension, obesity, and hyperkinetic hemodynamic states in children. j pediatr 2002;140(6):660-666. 18. flores-huerta s, klünder-klünder m, reyes de la cruz l, santos ji. increase in body mass index and waist circumference is associated with high blood pressure in children and adolescents in mexico city. arch med res 2009;40:208-215. 19. makgae pj, monyeki kd, brit sj, kemper hcg, mashita j. somatotype and blood pressure of rural south african children aged 6-13 years: ellisras longitudinal growth and health study. ann hum biol 2007;34(2):240251. 20. armstrong, meg, lambert, mi, lambert, ev. secular trends in the prevalence of stunting, overweight and obesity among south african children (1994-2004). eur j clin nutr 2011;65:835-840. 21. marfell-jones m, olds t, stewart a, carter jel. international standards for anthropometric assessment. isak: potchefstroom, 2006. 22. meredith md, welk gj. fitnessgram: test administration manual: the cooper institute for aerobics research. 2nd ed. champaign il: human kinetics publishers, 2005. 23. cole tj, belizzi mc, flegal km, dietz wh. establishing a standard definition for child overweight and obesity worldwide: international survey. bmj 2000;320:1240-1243. 24. national high blood pressure education program working group (nhbpep) on high blood pressure in children and adolescents. the fourth report on the diagnosis, evaluation and treatment of high bp in children and adolescents. pediatrics 2004;114(suppl. 2, 4th report):555-576. 25. statsoft. statistica for windows. release 5.5: general conventions & statistics. tulsa, ok: statsoft, 2010. 26. statistics south africa website www/statssa.gov.za/publicationstats.asp (accessed november 2009). 27. cohen j. statistical power analysis for the behavioural sciences. 2nd ed. hillsdale, nj: erlbaum, 1988. 28. hansen ml, gunn pw, kaelber dc. underdiagnosis of hypertension in children and adolescents. jama 2007;298:874-879. 29. cuestas e, achaval a, garces n, larraya c. waist circumference, dyslipidemia and hypertension in prepubertal children. ann pediatr 2007;67(1):44-50. 30. mahmud a, feely j. adiponectin and arterial stiffness. am j hypertens 2005;18:1543-1548. 31. iannuzzi a, licenziati mr, acampora c, et al. carotid artery wall hypertrophy in children with metabolic syndrome. j hum hypertens 2008;22:8388. 32. meyer aa, kundt g, steiner m, schuff-werner p, kienast w. impaired flow-mediated vasodilation, carotid artery intima-media thickening, and elevated endothelial plasma markers in obese children: the impact of cardiovascular risk factors. pediatrics 2006;117:1560-1567. 33. he fj, marrero nm, mcgregor ga. salt and blood pressure in children and adolescents. j hum hypertens 2008;22:4-11. 34. agyemang c, redekop wk, owusu-dabo e, bruijnzeels ma. blood pressure patterns in rural, semi-urban and urban children in the ashanti region of ghana, west africa. bmc public health 2005;5:114-120. 35. cruz ml, huang tt, johnson ms, gower ba, boran mi. insulin sensitivity and blood pressure in black and white children. hypertension 2002;40(1):18-22. 36. dekkers jc, snieder h, van den oord jcg, treiber fa. moderators of blood pressure development from childhood to adulthood: a 10-year longitudinal study. j pediatr 2002;141(6):770-779. 37. seedat yk. hypertension in black south africans. j hum hypertens 1999;13:97-103. 38. ferreira i, van der horst k, wendel-vos w, kremers s, van lenthe fj, brug j. environmental correlates of physical activity in youth – a review and update. obesity rev 2007;8(2):129-154. 39. addo j, leon da. socioeconomic position and hypertension: a study of urban civil servants in ghana. j epidemiol community health 2009;63(8):646-500. 52 sajsm vol 18 no.2 2006 introduction in addition to the medical support that is offered to an international team, medical coverage for spectators also needs to be provided at large sporting events. this has been highlighted by a number of incidents at soccer matches in particular. in 1992, 17 people were killed and 1 900 injured when a temporary stand collapsed in corsica. in the same year 43 and 126 people were killed as a result of spectators attempting to push their way into a soccer stadium in south africa and ghana, respectively. 1 further, the terrorist attack at the 1996 olympic games in atlanta where 111 people were injured 1 and the terrorist attacks in the usa on 11 september 2001 and in london in 2005, have made event organisers aware of the need for preparedness planning for large sporting events. medical coverage for the needs of spectators at large sporting events should cater for situations where medical personnel are able to deal with one case at a time, to events with isolated major incidents or in extreme cases such as a mass casualty or disaster situation. in preparation for the 2002 fifa world cup in japan, the health research team (hrt-mhlw) was established by the japanese government to provide an effective service for spectators attending the matches played in japan, as well as to analyse factors regarding patient presentations with a view to develop a medical care plan for mass gatherings. 3 a total of 1 661 patients presented with illness or injuries to the medical stations during the 32 matches played in japan. this patient presentation rate was 1.21/1 000 spectators, with a transport-to-hospital rate of 0.05/1 000 spectators. as the total number of spectators increased, the patient presentation rate decreased, while the patient presentation rates increased when spectators were not provided with shuttle-bus transport from the nearest railway station or had to walk for more than 12 minutes to gain access to the venue. while injuries to cricket players in south africa, 6-12 australia 5 and england 4 have been well documented over short communication analysis of patient load data from the 2003 cricket world cup in south africa a kilian1 (mb chb) r a stretch2 (d phil) 1 medical doctor in private practice, port elizabeth 2 sport bureau, nelson mandela metropolitan university, port elizabeth conclusion. the unique nature of cricket has shown a different patient presentation rate than for other similar mass gatherings, requiring additional factors be considered when developing a medical care plan. abstract objectives. the purpose of this study was to evaluate the patient presentation data for spectators attending the opening ceremony and all the 2003 cricket world cup matches played in south africa in order to provide organisers with the basis of a sound medical care plan for mass gatherings of a similar nature. methods. during the 2003 cricket world cup, data were collected on the spectators presenting to the medical facilities during the opening ceremony and the 42 matches played in south africa. data included the total number of patient presentations and the category of illness or injury. this information was used to determine the venue accommodation rate and the patient presentation rate. the illness/injury data were classified into the following categories: (i) heat-related illness; (ii) blisters/scrapes/ bruises; (iii) headache; (iv) fractures/sprains/lacerations; (v) eye injuries; (vi) abdominal pain; (vii) insect bite; (viii) allergy-related illness; (ix) cardiac disorders, chest pains; (x) pulmonary disorder/shortness of breath; (xi) syncope; (xii) weakness/dizziness; (xiii) alcohol/drug-related conditions; (xiv) seizure; (xv) cardiac arrest; (xvi) obstetric/ gynaecological disorder; and (xvii) other. results. the total number of patients who presented to the medical stations was 2 118, with a mean of 50 (range 14 91) injuries per match. the mean for the patient presentation rate was 4/1 000 spectators. the most frequently encountered illness or injury was headache (954 patients, 45%), followed by fractures, sprains and lacerations (351 patients, 16%). correspondence: r stretch sport bureau nelson mandela metropolitan university po box 77000 port elizabeth 6031 tel: 041-504 2584 fax: 041-583 2605 e-mail: richard.stretch@nmmu.ac.za pg52-56.indd 52 6/29/06 9:01:16 am sajsm vol 18 no.2 2006 53 the past number of years, there have not been any reported studies on the illness/injury rate of spectators attending major cricket matches or events. the purpose of this study was to evaluate the patient presentation data for spectators attending the opening ceremony and all the 2003 cricket world cup matches played in south africa and to compare these with similar findings from the 2002 fifa world cup held in japan, in order to provide organisers with a basis for a sound medical care plan for mass gatherings of a similar nature. method the 2003 cricket world cup was organised in february and march 2003, with the opening ceremony staged in south africa and 54 matches staged in south africa, zimbabwe and kenya. only the opening ceremony and the 42 matches played in south africa formed part of this study. the opening ceremony was held in the evening, with the one-day international matches played either as day matches (10h00 to about 17h30) or as day-night matches (14h30 to about 22h00). all the planning and procedures relating to the medical management of the spectators and players for all matches were the responsibility of the medical committee. only the spectator data are presented in this study. the medical committee held monthly meeting from january 2002 to may 2003 (16 meetings) and three seminars with the medical personnel prior to the start of the competition. based on this a medical system was put in place for each venue that would be able to respond to a disaster, as well as providing routine on-site medical emergencies. to ensure adequate medical cover there was at least one medical station at each ground, staffed by 2 doctors, 2 nurses and on average 3 paramedics. the medical support was provided from 2 hours before the start of the match to 1 hour after the end of the match. the necessary medical supplies and equipment were available at each medical station. an ambulance was available at each venue to transfer patients to hospital if necessary. further, at least one hospital in each city was put on stand-by in the event of an emergency, with the normal daily staff on stand-by. the data collected included the total number of spectators at each match and the maximum spectator capacity for each venue. the medical personnel in charge of the medical facility documented patient information which included the total number of patient presentations (pp) and the category of illness/injury (i). these data were used to determine the venue accommodation rate (var). this was defined as the actual number of spectators per game compared with the maximum spectator capacity of the venue. the patient presentation rate (ppr) was defined as the number of patients per 1 000 spectators per match. to allow comparisons with similar data from the 2002 fifa world cup 3 the illness/injury data were classified into the following: (i) heat-related illness; (ii) blisters/scrapes/ bruises; (iii) headache; (vi) fractures/sprains/lacerations; (v) eye injuries; (vi) abdominal pain; (vii) insect bite; (viii) allergy-related illness; (ix) cardiac disorders; chest pains; (x) pulmonary disorder/shortness of breath; (xi) syncope; (xii) weakness/dizziness; (xiii) alcohol/drug-related conditions; (xiv) seizure; (xv) cardiac arrest; (xvi) obstetric/gynaecological disorder; and (xvii) other. table i. spectator, venue and patient presentation data during the 2003 cricket world cup maximum mean venue presentations/ spectator accommodation % of total spectator patient 1 000 matches capacity rate capacity attendance presentations mean/match spectators venues (n) (n) (n) (%) (n) (n) (n) (n) paarl 3 9 030 4 207 47 12 620 57 19 4 durban 5 19 980 16 292 82 81 459 215 43 2 pietermaritzburg 3 7 091 3 883 55 7 765 42 21 5 potchefstroom 2 10 169 5 902 58 17 706 44 14 2 pretoria 4 21 160 15 427 72 61 706 366 91 5 johannesburg 5 30 542 26 235 86 131 175 427 85 3 kimberley 2 6 056 3 328 55 6 655 48 24 7 port elizabeth 5 18 109 12 206 67 61 031 241 48 3 cape town* 6 23 141 20 170 87 121 020 508 85 4 east london 2 13 248 5 610 42 11 220 36 18 3 benoni 2 9 812 4 719 48 9 437 49 25 5 bloemfontein 3 13 954 4 792 34 14 377 85 28 5 total 42 738 508 536 171 536 171 2 118 * the opening ceremony is included in these figures. pg52-56.indd 53 6/29/06 9:01:16 am 54 sajsm vol 18 no.2 2006 results there were 12 venues used to stage the 42 world cup matches, with an average of 4 (range 2 6) matches per venue. the mean maximum venue capacity was 17 583 (range 6 056 30 542) spectators, with a total capacity of 738 508 spectators for the venues for all 42 matches. the total attendance at all 42 matches was 536 171 spectators, with a mean actual attendance of 12 765 (range 3 328 26 235) or 73% (range 34 – 87%) of the total capacity for all the venues (table i). the total number of patients who presented to the medical stations was 2 118, with a mean of 50 (range 14 91) injuries or illnesses per match. the mean patient presentation rate was 4/1 000 spectators, with the matches played in potchefstroom and durban (3/1 000 spectators) and at kimberley (71/1 000 spectators) reporting the lowest and highest rates, respectively (table i). the most frequently encountered illness or injury was headache (954 patients, 45%), followed by fractures, sprains and lacerations (351 patients, 16%) (table ii). other presentations included allergy-related illnesses (129 patients, 6%), abdominal pain (120 patients, 6%) and heatrelated illnesses (103 patients, 5%). the ‘other’ category of illnesses or injuries (322 patients, 15%) included 88 (4%) patients with gastric problems and 48 (2%) and 19 (1%) with urinary tract and respiratory tract infections, respectively. discussion the unique nature of cricket, which is played over an extended period of time, has shown a different patient presentation rate than that of soccer.3 firstly, the cricket spectators showed a greater patient presentation rate per 1 000 spectators, although it still falls within the range of 0.14 90 patients per 1 000 spectators. 2 a number of factors may influence the patient presentation rate, with venue capacity and the crowd size being identified as the more important factors. 13 the crowd density is indicated by the venue accommodation rate. however, neither of these variables were factors in the patient presentation rate. the matches played at kimberley, the venue with the lowest mean venue accommodation rate, had the highest rate of injuries per 1 000 spectators. conversely, johannesburg, the venue with the greatest mean venue accommodation rate, had one of the lower rates of injuries per 1 000 spectators. this may possibly be due to the fact that a number of other factors such as weather conditions and location of seating may play a more significant role in the risk illness or injury to spectators at cricket matches. a second difference was that more than half of the patients at cricket matches presented with headaches and heat-related illnesses, while at soccer matches 3 this only made up about 15% of the recorded injuries/illnesses. again this may be related to other factors, some of which may be beyond the control of the event organisers. during the 2002 soccer world cup temperature had an effect on the number of injuries, with an increase in temperature associated with an increased risk of illness or injury, particularly heat-related illnesses, headaches and weakness or dizziness. 3 one of the limitations of the study was that no information was obtained on the weather conditions. although the effect of heat on the risk of illnesses or injury could not be determined, the 2003 cricket world cup was played in the hot summer months of february and march. in conclusion, the basic epidemiological data collected at the 2003 cricket world cup should assist organisers of future cricket world cup competitions to predict patient presentation rates. however, the unique nature of cricket requires additional factors that need to be considered when collecting similar data. this should include weather conditions, time of day or night when the patient presented, and information on whether the patient was seated in undercover seating or on the open grass banks that are common at many cricket grounds. this could then assist in developing a medical care plan in accordance with the capacity of the venue in order to provide the most efficient medical care possible. references 1. delaney js, drummond r. mass casualties and triage at a sporting event br j sports med 2002; 36: 85-8. 2. de lorenzo ra. mass gathering medicine: a review. prehosp disast med 1997; 12: 68-72. 3. morimura n, katsumi a, koido y, et al. analysis of patient load data from the 2002 fifa world cup korea/japan, prehosp disast med 2004; 19: 278 4. table ii. category of medical condition and the number (n) of patient presentations at the 2003 cricket world cup patient presentations (n) (%) blisters, scrapes and bruises 23 1 headache 954 45 abdominal pain 120 6 heat-related illnesses 103 5 fracture, sprain and lacerations 351 16 weakness/dizziness 6 1 cardiovascular disorders/chest pains 16 1 insect bites 25 1 pulmonary disorders/shortness of breath 19 1 alergy-related 129 6 eye injury 40 2 other 322 15 total 2 118 100 pg52-56.indd 54 6/29/06 9:01:29 am pg52-56.indd 55 6/29/06 9:01:46 am 56 sajsm vol 18 no.2 2006 4. newman da. prospective survey of injuries at first class counties in england and wales 2001 and 2002 seasons. in: stretch ra, noakes, td, vaughan cl, eds. science and medicine in cricket compress: cape town, 2003; 343-50. 5. orchard j, james t, alcott e, carter s, farhart p. injuries in australian cricket at first class level 1995/1996 to 2000/2001. br j sports med 2002; 36: 270-5. 6. stretch ra. injuries to south african cricketers playing at first-class level. s afr med j 1989; 4: 3-20. 7. stretch ra. the incidence and nature of injuries in club and provincial cricketers. south african medical journal 1993; 83: 339-41. 8. stretch ra. the incidence and nature of injuries in schoolboy cricketers. s afr med j 1995; 85: 1182-4. 9. stretch ra. incidence and nature of epidemiological injuries to elite south african cricket players. s afr med j 2001a; 91:336-9. 10. stretch ra. the incidence and nature of epidemiological injuries to elite south african cricket players over a two-season period, south african medical journal 2001b; 8:17 20. 11. stretch ra. cricket injuries: a longitudinal study of the nature of injuries to south african cricketers. br j sports med 2003; 37: 250 3. 12. stretch ra, venter djl. cricket injuries: a longitudinal study of the nature of injuries to south african cricketers. south african medical journal 2003; 15: 4 8. 13. zeitz km, schneider dp, jarrett d. mass gathering events: retrospective analysis of patient presentations over seven years. prehosp disast med 2002; 17: 147-50. case report 20 sa journal of radiology • march 2006 the diaphragm was demonstrated more clearly on the mri sequences and infiltration of the diaphragm could not be excluded on ct. another important role of ct or mri is to determine resectability and to detect metastases.2,3 they are also used in follow up to determine response to treatment2 and to detect recurrences. tc 99m-mdp (bone scan) is of value in detecting distant bony metastases8 and 8 f-fluoro-2-deoxy-glucose (fdg)-position emission tomography (pet) scan can be used to detect recurrence of intraspinal pnet.1,9 ct the ct picture is usually of heterogeneous soft tissue density.2,3 the mass can be isodense or slightly hypodense to muscle3 and larger tumours commonly have hypodense necrotic/cystic areas.2,3,6,8 post-contrast enhancement is mostly inhomogeneous.3,6,8 calcifications are seen in less than 10% of cases, but could be faint and speckled or stippled.6,8 haemorrhage can be seen as a hyperdense area in the mass if present. regional lymphadenopathy is rarely seen but chest wall invasion is more common and would be evidenced by pleural effusion, bony destruction, tumour nodules in the muscles and abnormal enhancement of the chest wall.8 mri mri t1-weighted images would show a mass isointense or slightly hyperintense to muscle2,3,5,6,8 with low-intensity areas correlating to cystic/necrotic areas in the tumour and hyperintense areas correlating to haemorrhage. post-gadolinium enhancement may be seen uniformly or inhomogeneously.2,3,5,6,8 heterogeneous high signal intensity is typically seen on t2-weighted images;2,3,5,6,8 this sequence usually demonstrates the cystic components best. a stir sequence would also demonstrate a heterogeneous high signal intensity mass.3,6 conclusion pnets are aggressive neoplasms and should therefore be diagnosed accurately and as early as possible. the distinction between pnet and es cannot be made radiologically and could even be difficult on histological examination. neural differentiation, immunostaining and immunohistochemistry can help to distinguish these tumours. unfortunately a standard therapy does not exist yet and patients are offered a combination of surgery, chemoand radiotherapy. prognosis depends on the location of the tumour but pnet has a generally poor prognosis. alternative treatment should be investigated further. 1. virani mj, jain s. primary intraspinal primitive neuroectodermal tumor (pnet): a rare occurrence neurology india 2002; 50: 75-80. 2. khong pl, chan gcf, shek twh, tam pkh, chan fl. imaging of peripheral pnet: common and uncommon locations. clin radiol 2002; 57: 272-277. 3. ibarburen c, haberman jj, zerhouni ea. peripheral primitive neuroectodermal tumors. ct and mri evaluation. eur j radiol 1996; 21: 225-232. 4. mawrin c, synowitz hj, kirches e, kutz e, knut d, weis s. primary primitive neuroectodermal tumor of the spinal cord: case report and review of literature. clin neurol neurosurg 2002; 104: 36-40. 5. kim yw, jin bh, kim ts, cho ye. primary intraspinal primitive neuroectodermal tumor at conus medullaris. yonsei med j 2004; 45: 538. 6. dorfmuller g, wurtz fg, umschaden hw, kleinert r, ambros pf. intraspinal primitive neuroectodermal tumour: report of two cases and review of literature. acta neurochirur 1999; 141: 1169-1175. 7. isotalo pa, agbi c, davidson b, girard a, verma s, robertson sj. primitive neuroectodermal tumor of the cauda equina. hum pathol 2000; 31: 999-1001. 8. dick ea, mchugh k, kimber c, michalski a. imaging of non-central nervous system primitive neuroectodermal tumours: diagnostic features and correlation with outcome. clin radiol 2001; 56: 206-215. 9. meltzer cc, townsend dw, kottapally s, jadali f. fdg imaging of spinal cord primitive neuroectodermal tumor. j nucl med 1998; 39: 1207-1209. 20 sa journal of radiology • march 2006 paraspinal.indd 20 3/27/06 12:25:57 pm case report 20 sa journal of radiology • march 2006 the diaphragm was demonstrated more clearly on the mri sequences and infiltration of the diaphragm could not be excluded on ct. another important role of ct or mri is to determine resectability and to detect metastases.2,3 they are also used in follow up to determine response to treatment2 and to detect recurrences. tc 99m-mdp (bone scan) is of value in detecting distant bony metastases8 and 8 f-fluoro-2-deoxy-glucose (fdg)-position emission tomography (pet) scan can be used to detect recurrence of intraspinal pnet.1,9 ct the ct picture is usually of heterogeneous soft tissue density.2,3 the mass can be isodense or slightly hypodense to muscle3 and larger tumours commonly have hypodense necrotic/cystic areas.2,3,6,8 post-contrast enhancement is mostly inhomogeneous.3,6,8 calcifications are seen in less than 10% of cases, but could be faint and speckled or stippled.6,8 haemorrhage can be seen as a hyperdense area in the mass if present. regional lymphadenopathy is rarely seen but chest wall invasion is more common and would be evidenced by pleural effusion, bony destruction, tumour nodules in the muscles and abnormal enhancement of the chest wall.8 mri mri t1-weighted images would show a mass isointense or slightly hyperintense to muscle2,3,5,6,8 with low-intensity areas correlating to cystic/necrotic areas in the tumour and hyperintense areas correlating to haemorrhage. post-gadolinium enhancement may be seen uniformly or inhomogeneously.2,3,5,6,8 heterogeneous high signal intensity is typically seen on t2-weighted images;2,3,5,6,8 this sequence usually demonstrates the cystic components best. a stir sequence would also demonstrate a heterogeneous high signal intensity mass.3,6 conclusion pnets are aggressive neoplasms and should therefore be diagnosed accurately and as early as possible. the distinction between pnet and es cannot be made radiologically and could even be difficult on histological examination. neural differentiation, immunostaining and immunohistochemistry can help to distinguish these tumours. unfortunately a standard therapy does not exist yet and patients are offered a combination of surgery, chemoand radiotherapy. prognosis depends on the location of the tumour but pnet has a generally poor prognosis. alternative treatment should be investigated further. 1. virani mj, jain s. primary intraspinal primitive neuroectodermal tumor (pnet): a rare occurrence neurology india 2002; 50: 75-80. 2. khong pl, chan gcf, shek twh, tam pkh, chan fl. imaging of peripheral pnet: common and uncommon locations. clin radiol 2002; 57: 272-277. 3. ibarburen c, haberman jj, zerhouni ea. peripheral primitive neuroectodermal tumors. ct and mri evaluation. eur j radiol 1996; 21: 225-232. 4. mawrin c, synowitz hj, kirches e, kutz e, knut d, weis s. primary primitive neuroectodermal tumor of the spinal cord: case report and review of literature. clin neurol neurosurg 2002; 104: 36-40. 5. kim yw, jin bh, kim ts, cho ye. primary intraspinal primitive neuroectodermal tumor at conus medullaris. yonsei med j 2004; 45: 538. 6. dorfmuller g, wurtz fg, umschaden hw, kleinert r, ambros pf. intraspinal primitive neuroectodermal tumour: report of two cases and review of literature. acta neurochirur 1999; 141: 1169-1175. 7. isotalo pa, agbi c, davidson b, girard a, verma s, robertson sj. primitive neuroectodermal tumor of the cauda equina. hum pathol 2000; 31: 999-1001. 8. dick ea, mchugh k, kimber c, michalski a. imaging of non-central nervous system primitive neuroectodermal tumours: diagnostic features and correlation with outcome. clin radiol 2001; 56: 206-215. 9. meltzer cc, townsend dw, kottapally s, jadali f. fdg imaging of spinal cord primitive neuroectodermal tumor. j nucl med 1998; 39: 1207-1209. 20 sa journal of radiology • march 2006 paraspinal.indd 20 3/27/06 12:25:57 pm case report 20 sa journal of radiology • march 2006 the diaphragm was demonstrated more clearly on the mri sequences and infiltration of the diaphragm could not be excluded on ct. another important role of ct or mri is to determine resectability and to detect metastases.2,3 they are also used in follow up to determine response to treatment2 and to detect recurrences. tc 99m-mdp (bone scan) is of value in detecting distant bony metastases8 and 8 f-fluoro-2-deoxy-glucose (fdg)-position emission tomography (pet) scan can be used to detect recurrence of intraspinal pnet.1,9 ct the ct picture is usually of heterogeneous soft tissue density.2,3 the mass can be isodense or slightly hypodense to muscle3 and larger tumours commonly have hypodense necrotic/cystic areas.2,3,6,8 post-contrast enhancement is mostly inhomogeneous.3,6,8 calcifications are seen in less than 10% of cases, but could be faint and speckled or stippled.6,8 haemorrhage can be seen as a hyperdense area in the mass if present. regional lymphadenopathy is rarely seen but chest wall invasion is more common and would be evidenced by pleural effusion, bony destruction, tumour nodules in the muscles and abnormal enhancement of the chest wall.8 mri mri t1-weighted images would show a mass isointense or slightly hyperintense to muscle2,3,5,6,8 with low-intensity areas correlating to cystic/necrotic areas in the tumour and hyperintense areas correlating to haemorrhage. post-gadolinium enhancement may be seen uniformly or inhomogeneously.2,3,5,6,8 heterogeneous high signal intensity is typically seen on t2-weighted images;2,3,5,6,8 this sequence usually demonstrates the cystic components best. a stir sequence would also demonstrate a heterogeneous high signal intensity mass.3,6 conclusion pnets are aggressive neoplasms and should therefore be diagnosed accurately and as early as possible. the distinction between pnet and es cannot be made radiologically and could even be difficult on histological examination. neural differentiation, immunostaining and immunohistochemistry can help to distinguish these tumours. unfortunately a standard therapy does not exist yet and patients are offered a combination of surgery, chemoand radiotherapy. prognosis depends on the location of the tumour but pnet has a generally poor prognosis. alternative treatment should be investigated further. 1. virani mj, jain s. primary intraspinal primitive neuroectodermal tumor (pnet): a rare occurrence neurology india 2002; 50: 75-80. 2. khong pl, chan gcf, shek twh, tam pkh, chan fl. imaging of peripheral pnet: common and uncommon locations. clin radiol 2002; 57: 272-277. 3. ibarburen c, haberman jj, zerhouni ea. peripheral primitive neuroectodermal tumors. ct and mri evaluation. eur j radiol 1996; 21: 225-232. 4. mawrin c, synowitz hj, kirches e, kutz e, knut d, weis s. primary primitive neuroectodermal tumor of the spinal cord: case report and review of literature. clin neurol neurosurg 2002; 104: 36-40. 5. kim yw, jin bh, kim ts, cho ye. primary intraspinal primitive neuroectodermal tumor at conus medullaris. yonsei med j 2004; 45: 538. 6. dorfmuller g, wurtz fg, umschaden hw, kleinert r, ambros pf. intraspinal primitive neuroectodermal tumour: report of two cases and review of literature. acta neurochirur 1999; 141: 1169-1175. 7. isotalo pa, agbi c, davidson b, girard a, verma s, robertson sj. primitive neuroectodermal tumor of the cauda equina. hum pathol 2000; 31: 999-1001. 8. dick ea, mchugh k, kimber c, michalski a. imaging of non-central nervous system primitive neuroectodermal tumours: diagnostic features and correlation with outcome. clin radiol 2001; 56: 206-215. 9. meltzer cc, townsend dw, kottapally s, jadali f. fdg imaging of spinal cord primitive neuroectodermal tumor. j nucl med 1998; 39: 1207-1209. 20 sa journal of radiology • march 2006 paraspinal.indd 20 3/27/06 12:25:57 pm to order contact carmen or avril: tel: (021) 530-6520 fax: (021) 531-4126/3539 email: carmena@hmpg.co.za the south african medical association, health & medical publishing group 1-2 lonsdale building, gardener way, pinelands, 7405. pg52-56.indd 56 6/29/06 9:02:06 am original research 1 sajsm vol. 29 2017 ultrasound comparison of the effects of prehabilitation exercises and the scapular assistance test on the acromiohumeral distance m m gous, mtech1, b van dyk, mtech2, e j bruwer, phd3 1 department of medical imaging and radiation sciences, faculty of health sciences, university of johannesburg, johannesburg, south africa 2 department of medical imaging and radiation sciences, faculty of health sciences, university of johannesburg, johannesburg, south africa 3 department of physical activity, sport and recreation (phasrec), north west university, potchefstroom, south africa corresponding author: mm gous (magdeleen.gous@gmail.com) subacromial impingement syndrome (sis) is commonly encountered in overhead athletes when one arm is used in an overhead position. although a complete throwing motion only lasts a few seconds, repetitive overhead motion creates significant stress on the shoulder, resulting in muscle imbalances which heighten the risk of developing sis.[1] prolonged muscle imbalances lead to a narrowing of the acromiohumeral distance (ahd) and painful compression of the soft tissue structures which pass through the subacromial space (sas) during dynamic humeral abduction. [2,3[ a late diagnosis of sis may lead to decreased sport performance while valuable training and competition time is lost due to long periods of rehabilitation.4 the scapular assistance test (sat) is used to identify abnormal scapular motion before late stage winging is present. the examiner manually corrects the dyskinesis and stabilises the scapula on the bony thorax by rotating the scapula upward and outwards, while simultaneously pushing the scapula to increase the posterior tilt during humeral elevation. [5,6] the sat manoeuvre relieves compression on soft tissue structures responsible for sis by increasing the ahd. the test is therefore positive when the athlete’s symptoms are reduced with the abduction of the humerus while the sat is applied. [5,6,7] if pain reduces with the sat, it may be assumed that the strengthening of the scapular stabilisers will result in a widening of the ahd and the lessening of the clinical effects of sis. however, in the sporting world it would be helpful to determine whether the prehabilitation of the shoulder girdle is needed before the onset of impingement symptoms. determining the ahd, before and after the sat application, at different angles of humeral abduction in the dominant and non-dominant shoulders of unilateral overhead athletes could provide valuable insight into the type of soft tissue injury and contribute to its mitigation. there is currently no proven imaging or clinical method to identify the risk of future sis in asymptomatic overhead athletes. ultrasound is a non-invasive, comfortable and dynamic examination which provides extensive diagnostic information of the shoulder muscles, as well as the ahd variation, during the abduction of the humerus.8 although ultrasound can accurately measure the ahd, the literature is not clear as to whether it can predict sis in overhead athletes by measuring the ahd at different humeral abduction angles.8 the purpose of this article is to describe the use of ultrasound ahd measurements to compare the effect of sat on the ahd with that of a prehabilitative exercise intervention in asymptomatic cricket players. methods study design and participants male cricket players (n=47) from the north-west university (nwu) cricket squad were recruited to voluntarily participate in this randomised control trial during the 2013 cricket season. ethical approval was obtained from the faculty of health sciences higher degrees and research ethics committees at the university of johannesburg (aec12-01-2013) and the nwu (nwu-00026-12-a1). players and coaches were thoroughly background: prolonged participation in overhead sports creates shoulder muscle imbalances which eventually alter the efficacy of the shoulder stabiliser muscles and heighten injury risk, such as subacromial impingement syndrome. objectives: the aim of this study was to determine if ultrasound is effective to measure the acromiohumeral distance (ahd) to compare the effect of the scapular assistance test (sat) on the ahd with a prehabilitative exercise intervention programme in asymptomatic cricket players. methods: baseline testing on cricket players from the northwest university cricket squad (n=34) included ahd measurements performed by a sonographer at 0°, 30° and 60° humeral abduction angles respectively, with and without the sat application. players were then randomly assigned to an intervention and control group. the control group continued with their normal in-season programme, whereas the intervention group also performed shoulder stability exercises for six weeks. results: the exercise intervention had a similar effect as the sat on the ahd at 0º and 30º humeral abduction angles in the intervention group. the ahd measurements in the exercise intervention group indicated widening at all abduction angles after the six-week intervention period, whereas the ahd measurements in the control group were equal or smaller than baseline measurements without the sat at 30º and 60º respectively. conclusion: exercise intervention has a similar effect on the ahd of asymptomatic cricket players compared to the sat – especially in 0°and 30º of humeral abduction. ultrasound can therefore be utilised to assist in identifying the risk of developing subacromial impingement syndrome (sis) in asymptomatic overhead athletes by measuring the ahd at different angles of humeral abduction, without and with the sat application. keywords: acromiohumeral distance, subacromial impingement syndrome, overhead athletes s afr j sports med 2017;29:1-6. doi: 10.17159/2078-516x/2017/v29i0a1396 mailto:magdeleen.gous@gmail.com http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1396 original research sajsm vol. 29 2017 2 informed regarding the testing procedures and the exercise intervention programmes. written informed consent was obtained from all participating players prior to baseline ultrasound examinations of both shoulders and participation in the testing procedures and exercise intervention programmes. only players of ≥17 and ≤ 25 years, who did not suffer from any current orthopaedic condition or injury or who were not rehabilitating from any orthopaedic injury, were eligible for inclusion in this study. the study population was randomly allocated to an exercise intervention group and a control group by participants drawing numbers from a box after the baseline testing. thirty-four participants completed the posttest procedures (exercise intervention group, n=16 and control group, n=18). ultrasound measurements both shoulders of prospective participants were initially examined with ultrasound to rule out any pre-existing pathology. a baseline ultrasound examination was then performed on all participants who met the study criteria. a japanese manufactured hitachi aloka f75 ultrasound unit, equipped with a 7mhz – 14mhz linear broadband transducer, was used for this purpose. the ahd of both shoulders was measured at 0º, 30º and 60º humeral abduction angles in the scapular plane, with and without application of the sat. the transducer was positioned in a sagittal plane along the long axis of the supraspinatus tendon and humerus (fig. 1a). the ahd on the frozen image can then be defined as the shortest linear distance between the antero-inferior tip of the acromion and the greater tubercle of the humeral head (fig. 1b). [10] the degrees of humeral abduction were measured with a goniometer, placed on the posterior aspect of the shoulder along the long axis of the humerus (fig. 2a). [3,6,9] ahd measurements of more than 60° humeral abduction are not possible due to constraints in the imaging technique. [9] the sat was then applied by a qualified biokineticist who manually rotated the scapula in an upward rotation and posterior tilt during humeral abduction to manually stabilise the scapula on the bony thorax. [5,6] the ahd was remeasured at the same 0°, 30° and 60° humeral abduction angles (fig. 2ab). to ensure internal validity, an independent radiologist audited all the ultrasound images to verify that the correct technique had been used consistently in obtaining the required images and in measuring the ahd. exercise intervention while continuing with the usual in-season cricket training, the intervention group was also subjected to a six-week exercise intervention programme, twice a week for forty minutes at a time, under the supervision of a qualified biokineticist. the exercise intervention programme focused on releasing the pectoralis minor, pectoralis major, latissimus dorsi and posterior capsule, as well as strengthening the scapular and core stabiliser muscles and humeral lateral rotators. emphasis was placed on maintaining postural control during the execution of all exercises. a register was kept to log each session the athlete attended and only participants who complied with attending two sessions per week throughout the six week period qualified for follow-up testing. conversely, the control group carried on with the usual inseason cricket training and exercises under the supervision of the cricket coach, without the additional biokinetic intervention. follow-up ahd measurement on completion of the prehabilitative exercise programme, the ahd of both shoulders was re-measured as previously described, albeit without the sat application. these measurements served as comparative information of the increase in ahd measurement achieved both with the sat application, as well as with the prehabilitation exercises. a comparison of the follow-up ahd measurements without the sat to the initial ahd measurements with the sat, was expected to support or refute the hypothesis that the strengthening of the scapula stabilisers act in the same manner as the sat application. statistical analysis the statistical analyses were performed using the ibm spss v24 programme (ibm corp. released 2016. ibm spss statistics for windows, version 24.0. armonk, ny: ibm corp). based on the results of the shapiro-wilk test and quantile-quantile plots, these authors concluded that the sample was normally distributed and therefore parametric statistical methods were used. independent t-tests were performed to determine if the exercise intervention and control groups differed in basic participant characteristics. repeated measures anova tests with between-subjects effects (exercise intervention and control groups) and within-subjects effects (dominant vs nondominant shoulders and humeral abduction angles) were performed to indicate the difference in ahd at 0º, 30º and 60º of humeral abduction for both the dominant and non-dominant shoulders without the sat at baseline. lastly, repeated measures anova tests were also performed with betweensubjects effects (intervention and control groups) and withinsubjects effects (ahd at 0º, 30º and 60º humeral abduction angles at baseline with and without the sat, as well as the postintervention period without the sat) to indicate whether the effect of the sat and the exercise intervention differed. results the biographical and anthropometrical characteristics of the sample are summarised in table 1. the groups presented with similar characteristics making them suitable for comparison (table 1). in fig. 3, the change in the baseline ahd measurement, without the sat at 0º, 30º and 60º humeral abduction angles, is indicated for both the dominant and non-dominant shoulders of the intervention and control groups. there were no significant three-way or two-way interactions. a significant main effect between the humeral abduction angles (f2,64=43.86, p<0.001) was observed, indicating that the ahd varies irrespective of dominance or group. multiple comparisons with original research 3 sajsm vol. 29 2017 a bonferroni correction was used to indicate that the mean ahd of both groups significantly narrowed during humeral abduction from 0º to 30º (p=0.002), 0º to 60º (p<0.001) and from 30º to 60º (p<0.001). when measured separately, the ahd of both shoulders showed a similar narrowing trend during 0º to 30º and 30º to 60º humeral abduction. in figure 4 the baseline ahd measurement of the dominant shoulder (throwing arm) without sat of the exercise intervention and control groups was compared to the baseline ahd with sat and after the intervention without sat at 0º, 30º and 60º humeral abduction angles. there were no significant three-way interactions observed between 0º, 30º and 60º humeral abduction angles and the application of the sat at baseline of the exercise intervention or control groups. significant two-way interactions were observed between the 0º, 30º and 60º humeral abduction angles and application of sat at baseline of the exercise intervention (f2,30=3.810, p=0.034) and control (f2.34=5.100, p=0.012) groups, indicating that the ahd with the sat increases significantly during 0º, 30º and 60º humeral abduction angles compared to the ahd without the sat at similar abduction angles. multiple comparisons with a bonferroni correction was used to indicate that the mean ahd of the intervention group widened with the sat at humeral abduction angles of 0º (p=0.020), 30º (p=0.031) and 60º (p=0.047). the mean ahd of the control group widened with the sat at humeral abduction angles of 0º (p<0.001), 30º (p=0.002) and 60º (p<0.001). the ahd was of medium practical significance (dvalues) at 0º (d=0.50), small to medium practical significance at 30º (d=0.45), and of medium to large practical significance at 60º (d=0.76) abduction in the intervention group. the ahd was of medium practical significance (d-values) at 0º (d=0.50), of small to medium practical significance at 30º (d=0.43), and of large practical significance at 60º (d=0.85) abduction in the control group. there were no significant two-way interactions observed between the ahd of the exercise intervention (f2,30=0.066, p=0.936) or control groups (f2,1=1.292, p=0.748) at humeral abduction angles of 0º, 30º and 60º without the sat at baseline and the ahd at similar humeral abduction angles without the sat after the six-week exercise intervention period. there were no significant three-way interactions observed between the ahd with the sat at baseline and the ahd without the sat after the six-week exercise intervention period at humeral abduction angles of 0º, 30º and 60º of the exercise intervention or control groups. significant two-way fig. 1a and 1b. ahd measurement at 0° humeral abduction (author’s personal collection). fig. 2a and 2b. ahd measurement at 60° humeral abduction without and with the application of the sat (author’s private collection). 1a 1b 2a 2b original research sajsm vol. 29 2017 4 0 30 60 0 30 60 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 exercise intervention dominant non-dominant a cr om io h u m e r a l d i s t a n c e (c m ) ° ° ° ° ° ° 0 30 60 0 30 60 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 control dominant non-dominant a crom iohum eral distance (cm ) ° °°°°° 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 exercise intervention a cr om io hu m er al di st an ce (c m ) 0° 30° 60° * * * + 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 control 0° 30° 60° * * * +++ a crom iohum er al d ist an c e ( cm ) adh without sat adh with sat adh post exercise humeral abduction angles (degrees) table 1. comparison of biographical characteristics between the exercise intervention and control groups (n=34) variables intervention (n=16) control (n=18) p-value age (years) 20.7±1.3 20.9±1.5 0.826 height (m) 1.81±0.07 1.79±0.07 0.202 body mass (kg) 81.4±9.4 77.5±10.3 0.315 bmi (kg.m-2) 24.7±1.7 24.0±2.3 0.786 number of years participating < 4 years 1(6%) 1(6%) 0.957 ≥ 4 years 15(94%) 17(94%) participating level university squad 12(75%) 15(83%) 0.163 provincial level 4(25%) 3(17%) average training hours per week < 6 hours 4(25%) 7(39%) 0.586 ≥ 6 hours 12(75%) 11(61%) history of resistance training < 3 years 10(63%) 7(39%) 0.182 ≥ 3 years 6(38%) 11(61%) values reported as either mean ± sd or as number of participants (% of total participants). significance is set at p < 0.05 fig. 4. comparison of baseline ahd of the exercise intervention and control groups with and without the sat and after intervention without the sat at 0º, 30º and 60º of humeral abduction fig. 3. comparison of baseline ahd measurements at 0º, 30º and 60º humeral abduction without the sat original research 5 sajsm vol. 29 2017 interactions were observed between the ahd with the sat at baseline and the ahd without the sat after the six-week intervention period at 0º, 30º and 60º humeral abduction angles of the exercise intervention (f2,30=5.979, p=0.007) and control (f2,34=5.909, p=0.006) groups. multiple comparisons with a bonferroni correction was used to indicate that there is no significant difference between the ahd with sat at baseline and the ahd without the sat after the six-week intervention period in the exercise intervention group at 0º (p=0.538) or 30º (p=0.396) humeral abduction angles. the ahd of the exercise intervention group does, however, differ statistically at 60º (p=0.001) humeral abduction angle. the ahd of the control group at baseline with the sat does differ statistically from the ahd without the sat after the six-week study period at 0º (p=0.015), 30º (p=0.010) and 60º (p=0.001) humeral abduction angles. note however, no significant difference was observed between the effect of the sat and the exercise intervention on the ahd at 0°and 30°of humeral abduction in the intervention group, thus indicating that the six-week exercise intervention has a similar effect on the ahd at these angles as when the sat was applied. the ahd of the control group after the intervention period was significantly less than when the sat was applied, indicating that normal conditioning regimes did not have any positive effects on the ahd. discussion the study aimed to test the hypothesis that prehabilitative exercises would correct upper body postural adaptations and shoulder muscle imbalances in a similar way as the sat manually alters the orientation of the scapula to increase the ahd. this was achieved by comparing the effect of the sat on the ahd to the initial baseline measurements without the sat at 0º, 30º and 60º humeral abduction angles and also to the effect of a six-week biokinetics prehabilitation intervention programme on ahd measurements without the sat. the baseline ahd measurements of the dominant and nondominant shoulders were almost identical in both groups before the sat was applied. the assumption that the application of the sat would increase the ahd in both groups at baseline was proved correct. the greatest effect of the sat was, however, observed in the dominant shoulder of overhead athletes. weakness of the serratus anterior and upper or lower trapezius muscles, as well tightness of the posterior capsule, result in anterior tipping of the scapula with subsequent sis.[11,12] the sat is believed to alter the scapular position through manual upward rotation and posterior tipping to increase the ahd, thus limiting compression of the rotator cuff and subacromial-subdeltoid bursa in the same way that prehabilitation exercises would strengthen the scapular stabiliser muscles and reposition the scapula to prevent sis.[2,3,5,13,14] when the mean ahd with the sat was compared to the ahd without the sat, after completion of the six-week prehabilitation programme, widening of the ahd was evident in the exercise intervention group at 0º and 30º humeral abduction angles – most significantly at 30° of humeral abduction. this implies that the intervention had the same effect on the ahd as the sat by mitigating muscle imbalances associated with a repeated overhead motion resulting in a smaller chance of developing sis. the same general trend was not observed in the control group. with ahd distances smaller than the initial baseline measurements with the sat, it can be deduced that normal training had no positive effect on the ahd in the control group. on the contrary, it seems as if the reduced ahd in the dominant shoulders at 0º, 30º and 60º abduction suggests scapular imbalances which may result in sis over time. a study by silva et al. [4] similarly reported that asymptomatic tennis players with postural adaptations presented with a smaller ahd than control non-playing participants, as well as tennis players without shoulder dyskinesia which highlights the importance of preventative exercises to limit the condition. the results of this study thus suggest that ahd measurements of the intervention group without the sat application after a six-week intervention period are wider than baseline ahd measurements without the sat at all angles of humeral abduction, and almost similar to ahd measurements with the sat at baseline. these measurements, therefore, confirm that scapular stabilisation prehabilitation exercises do act in a similar manner as the sat. as a non-invasive, nonradiating and dynamic examination, ultrasound provides extensive diagnostic information of the shoulder muscles, as well as the variation in the ahd, during abduction of the humerus. [8] accurate measurements over 60º can, unfortunately, not be provided due to constraints in the imaging technique. [8,9,10,15] furthermore, musculoskeletal ultrasound examinations are operator-dependent which may render less accurate results when performed by a less experienced operator. nevertheless, this study indicated that a different interdisciplinary approach may be useful in the conservative treatment of sis. orthopaedic surgeons and sports physicians may consider referring patients with secondary shoulder impingement symptoms, for ultrasound imaging which includes a measurement of the ahd when the sat is applied. a conservative exercise rehabilitation programme, prescribed by a biokineticst, could then be followed for a predetermined period of time (six weeks in this study) in the hope of mitigating surgical intervention. conclusion this research aimed to describe the use of ultrasound ahd measurements to compare the effect of the sat on the ahd with that of a prehabilitative exercise intervention in asymptomatic cricket players. the results of this study indicate that exercise intervention has a similar effect on the ahd of asymptomatic cricket players as the sat – especially in 0°of humeral abduction. ultrasound can, therefore, be utilised to assist in identifying the risk of developing sis in asymptomatic overhead athletes, by measuring the ahd at different angles of humeral abduction, without and with the sat application. with the sat having a more pronounced effect on the dominant shoulder as compared to the non-dominant shoulder, it can be expected that the athlete may develop sis in future as a original research sajsm vol. 29 2017 6 result of postural adaptations and scapular muscle imbalances already present. the findings of this study propose the use of a standardised ultrasound protocol for the evaluation of the shoulder in unilateral overhead athletes. a multidisciplinary team, consisting of biokineticists, sport scientists, coaches and sonographers, are encouraged to consider the use of high frequency sound imaging as an additional screening tool for the timely detection of sis risk and correction of muscle imbalances before the onset of symptoms. such a protocol has the ability to pre-empt decreased sport performance and loss of valuable training and competition time at a competitive level due to injury. acknowledgements: the authors wish to acknowledge ms marike cockeran, school for computer, statistical and mathematical sciences, north-west university, for her statistical support. references 1. kirchhoff c, imhoff ab. posterosuperior and anterosuperior impingement of the shoulder in overhead athletes – evolving concepts. int ortop 2010;34:1049-1058. [doi: 10.1007/s00264010-1038-0] 2. kibler wb. current concepts: the role of the scapula in athletic shoulder function, am j sports med 1998;26:325-337. [doi: 10.1177/03635465980260022801] 3. seitz al, mcclure pw, finucane s, et al. the scapular assistance test results in changes in scapular position and subacromial space but not rotator cuff strength in subacromial impingement, j orthop sports phys ther 2012;42:400-412. [doi:10.2519/jospt.2012.3579] 4. silva rt, hartman lg, de souza lcf, et al. clinical and ultrasonographic correlation between scapular dyskinesia and subacromial space measurement among junior elite tennis players, br j sports med 2010;44:407-410. [doi: 10.1136/bjsm.2008.046284] 5. sauers el. clinical evaluation of scapular dysfunction, athl ther today 2006;11:10-14. [https:// doi.org/10.1123/att.11.5.10] 6. seitz pl, mcclure pw, lynch ss,et al. effects of scapular dyskinesis and scapular assistance test on subacromial space during static arm elevation, j shoulder elbow surg 2012;21:631-640. [doi: 10.1016/j.jse.2011.01.008] 7. phadke v, camargo p, ludewig p. scapular and rotator cuff muscle activity during arm elevation: a review of normal function and alterations with shoulder impingement, rev bras fisioter 2009;13:1-9. [doi: 10.1590/s1413-35552009005000012] 8. azzoni r, cabitza p, parrini m. sonographic evaluation of subacromial space. ultrasonics 2004;42:683-687. [doi: 10.1016/j.ultras.2003.11.015] 9. desmeules f, minville l, riederer b,et al.. acromio-humeral distance variation measured by ultrasonography and its association with the outcome of rehabilitation for shoulder impingement syndrome. clin j sport med 2004;14:197-205. [https://doi.org/10.1097/00042752-200407000-00002] 10. kumar p, bradley m, swinkels a. within-day and day-to-day intrarater reliability of ultrasonographic measurements of acromion-greater tuberosity distance in healthy people, physiother theory pract 2010;26:347-351. [doi: 10.3109/09593980903059522] 11. miller md, thompson sr. delee & drez’s orthopaedic sports medicine: principles and practice. 3rd ed. philadelphia: saunders, 2010:892. 12. muraki t, yamamoto n, zhao kd, et al. effects of posterior tightness on subacromial contact behavior during shoulder motions, j shoulder elbow surg 2012;21:1160-1167. [doi:10.1016/j.jse.2011.08.042] 13. rabin a, irrgang jj, fitzgerald gk, et al. the intertester reliability of the scapular assistance test, j orthop sports phys ther 2006;36:653-660. [doi:10.2519/jospt.2006.2234] 14. kibler bw, mcmullen j. scapular dyskinesis and its relation to shoulder pain, j am acad orthop surg 2003;11:142-151. [https:// doi.org/10.5435/00124635-200303000-00008] 15. cholewinski jj, kusz dj, wojciechowski p, et al. ultrasound measurement of rotator cuff thickness and acromio-humeral distance in the diagnosis of subacromial impingement syndrome of the shoulder, knee surg sports traumatol arthrosc 2007;16:408-414. [doi: 10.1007/s00167-007-0443-4] doi:%2010.1007/s00264-010-1038-0 doi:%2010.1007/s00264-010-1038-0 doi:%2010.1177/03635465980260022801 doi:10.2519/jospt.2012.3579 doi:%2010.1136/bjsm.2008.046284 doi:%2010.1136/bjsm.2008.046284 doi:%2010.1016/j.jse.2011.01.008 doi:%2010.1590/s1413-35552009005000012 doi:%2010.1016/j.ultras.2003.11.015 doi:%2010.1016/j.ultras.2003.11.015 https://doi.org/10.1097/00042752-200407000-00002 doi:%2010.3109/09593980903059522 doi:%2010.3109/09593980903059522 doi:10.1016/j.jse.2011.08.042 doi:10.2519/jospt.2006.2234 doi:%2010.1007/s00167-007-0443-4 introduction internationally, squash has been identified as a fast-growing sport. 10 there are currently 15 million players worldwide from 135 participating nations. 10 the ongoing increase in popularity has been associated with an increase in competitive levels in school leagues, at provincial level and even at national level. young squash players are now participating at relatively more competitive levels of play compared with 20 years ago. 10 this shift in focus among young people from enjoyment of physical activity to competitiveness is placing high demands on the musculoskeletal and physical systems. 10 squash-related musculoskeletal injuries can occur to the upper and lower limbs or back. 11 the general injury prevalence among squash players is about 45%. 3 a critical review of squash epidemiological studies indicated that squash players most commonly report acute soft-tissue injuries at hospital emergency departments. 11 lower-limb injuries account for the majority of the injuries sustained by squash players. 11 the knee and ankle joint are reportedly the most commonly injured body regions in squash. 11 the shoulder joint is the most frequently injured upper-limb region. 3 squash is a high-intensity sport that requires high-speed movements around the court while maintaining control over ball placement and being aware of the spatial orientation of the opponent. 11 in order to hit the ball, squash players need large range of joint motion and velocity of limb action. 11 injury risk factors in squash include the physical demands of the sport, the speed, size and physical properties of the ball, court surfaces, the confined area of play and close proximity of players when swinging a racket. 11 original research article prevalence of musculoskeletal injuries among adolescent squash players in the western cape l meyer (bsc physio) l van niekerk (bsc physio) e prinsloo (bsc physio) m steenkamp (bsc physio) q louw (bsc, masp, phd) division of physiotherapy, stellenbosch university, w cape abstract objective. to determine the prevalence of musculoskeletal injuries among adolescent squash players in the western cape. design. a retrospective descriptive survey was conducted during the first week of may 2006. three schools were randomly selected from a list of the top 10 schools in the western cape high school squash league of 2005, with 106 squash players aged 13 18 years participating in the study. setting. injury data were collected for 106 players at three schools randomly selected from a list of the top 10 schools in the western cape high school squash league of 2005. interventions. an adapted structured self-administered questionnaire based on a previously validated musculoskeletal injury questionnaire was used to collect the data. main outcome measures. the main variables investigated were prevalence, mechanism and injury site of musculoskeletal squash injuries. results. twenty-nine per cent of the players (n = 31) reported that they had sustained a squash injury in the 4 weeks prior to data collection. a total of 48 injuries were reported by the injured players. the most common injuries included those of the thigh (19%), shoulder (13%) and lower back (13%). forty-two per cent of players reported no specific mechanism of injury, but experienced pain correspondence: q louw department of physiotherapy stellenbosch university po box 19063 7505 tel: 021-938 9300 fax 021-931 1252 e-mail: qalouw@sun.ac.za not associated with a traumatic injury only while playing squash. conclusion. a relatively high prevalence of squash injuries was found. this preliminary study serves as a baseline for future research. areas for further investigation were identified and this could lead to the implementation of preventive programmes and education to prevent injuries among adolescent squash players. sajsm vol 19 no. 1 2007 � pg3-8.indd 3 4/4/07 10:25:53 am � sajsm vol 19 no. 1 2007 the maturing adolescent musculoskeletal system may increase the risk of musculoskeletal injury. 5 preadolescent and adolescent players have open growth plates, reduced muscle power, lower levels of co-ordination and smaller stature than adult players. 5 decreased soft-tissue flexibility is also evident in adolescents due to the inability of soft tissues to accommodate the rapid growth of skeletal structures such as the long bones of the femur. 14 the biomechanical demands placed on the vulnerable neuro-musculoskeletal system of young people by high-intensity sports such as squash may be an injury risk factor. 17 a search of the published literature indexed in electronic databases since 1995 revealed that squash injury literature has paid greatest attention to the problem of eye injuries. 9,11 no published literature was found on the prevalence of squash injuries among adolescent players. the literature search of electronic databases also indicated that no epidemiological research into squash injuries has been published over the past 10 years. a manual search of the south african journal of sports medicine since 1990 also yielded no reference to publications on squash injuries among south africans. the aim of this study was therefore to ascertain the prevalence and types of injuries among high school squash players in the western cape. methods study design a retrospective descriptive survey with a recall period of 4 weeks was conducted to ascertain the injuries that were most common amongst adolescent squash players in the western cape high school squash league. the western cape education department granted permission to conduct the study. ethical approval to conduct the study was obtained from stellenbosch university. players signed an informed consent form before participating in the study. the questionnaire was completed anonymously to ensure the anonymity of all the players. subject selection the population comprised adolescent high school squash players in the western cape. a list of the top 10 high schools in the western cape high school squash league of 2005 was obtained from the co-ordinator of the western cape provincial squash teams. three schools were then randomly selected from the list of the top 10 schools, using a randomised table. after the three selected schools had verbally agreed to participate, an email was sent to the coach of each school outlining the project aims and the procedure of the study. epi-info statcalc version 3.3 (georgia, usa) was used to determine the sample size. published reports on adolescent sport injury prevention ascertained that the injury prevalence was about 12%. 18 it was determined that about 108 players were required, based on an expected injury prevalence of 12% and 80% statistical power. the inclusion criteria of the study were: (i) male and female squash players registered as participants in the high school squash league of 2006; (ii) adolescent squash players aged 13 18 years old; and (iii) players who had completed an informed consent form. the exclusion criterion of the study was players who were absent on the day of data collection. data collection the instrument used by the researchers for the purpose of the study was an adapted structured self-administered questionnaire based on a previously validated questionnaire used for adolescent basketball players in cape town. 18 this study focused on the prevalence of squash injuries in adolescent players and not on the injury patterns found specifically in the knee, as in the study on basketball players conducted by louw et al. 18 questionnaire information such as warm-up, level of play, and the number of hours played per week was regarded to be appropriate for this study. the questionnaire was divided into two sections to collect general information and injury information data. injury information consisted of all squash-related musculoskeletal injuries sustained during the 4 weeks prior to data collection as well as injuries sustained in any other structured sport before this period. the participants could report all body parts injured during the study period of 4 weeks in the table provided in the questionnaire. players also reported on the hours played per week, warm-up, level of play and treatment received for sustained injuries (table i). the questionnaires were validated for face, content and construct validity. two experienced researchers who had previously conducted similar epidemiological studies were consulted to evaluate the questionnaire content validity. the table i. summary of questionnaire content i. personal information age, gender, handedness, starting age of playing squash ii. frequency of play playing hours per week, number of days play per week iii. warm-up activities during these sessions iv. general injuries sustained reporting of any injury to a body part prior to the last month v. squash injuries injuries sustained during the last 4 weeks, mechanism of injury, body part injured vi. treatment received any type of treatment received, e.g. physiotherapy, rest, medication pg3-8.indd 4 4/4/07 10:25:54 am consulted researchers were of the opinion that the content of the questionnaire was valid. the questionnaire was translated and back-translated from english into afrikaans by professional translators. to assess construct validity, the questionnaire was piloted among 20 high school squash players to assess whether they understood all the questions. the players experienced no problems in answering the questionnaire, and no changes were subsequently made to the questionnaire. data were collected retrospectively over a 4-week period and similar recall time frames have been employed in published reports of adolescent sports injuries. 12 to determine reliability, player responses were verified by surveying the parents in a manner described by grimmer et al. 12 a sub-sample 10 questionnaires were selected randomly using a randomisation table. the parents of these players were telephoned after completion of the data collection to verify the responses of the young players. there was 100% agreement between the responses of parents and their children, indicating reliability of the player responses. permission was obtained from the selected schools, the western cape education department and coaches. the researchers visited two of the schools at the squash courts during practice and one at the end of the school day to collect the data. the data at all three schools were collected during the same week. at each school the researchers explained the purpose of the study, emphasising that players should only report on squash injuries that had occurred in the 4 weeks prior to data collection. the researchers were present during the completion of the questionnaires to attend to any queries. questionnaires took approximately 15 minutes to complete and were collected immediately to ensure a high response rate. injury definition an injury was defined as one that occurred during practice or competition resulting from a traumatic incident. the definition also encompassed overuse injuries not initiated by a specific traumatic incident, but causing symptoms including pain or swelling while or after player squash. 2 statistical analysis the data were analysed descriptively by calculating percentages of occurrences, and statistically by using the chi-square test for determining if potentially significant relationships existed between variables. analyses were done using statistica version 7.1 (www.statsoft.com). probability estimates (odds ratios (ors)) were calculated to assess the effect of injury-related factors such as gender, not warming up, playing for a club and pre-existing injury. significant risk was identified by 95% confidence limits around odds ratios where neither 95% confidence limits encompassed the value of 1. odds ratios were also calculated using epi-info version 3.3 (georgia, usa). results sample description the sample consisted of 106 high school squash players. boy and girl team players as well as the reserves were part of the sample if they were eligible to participate. approximately 70% of the respondents were male and 30% female. the average age for females was 16.0 ± 1.2 years and the average age for males 16.0 ± 1.3 years (table ii). none of the players was absent on the day of data collection. consent was obtained from all squash players. one hundred and nine questionnaires were completed by the players. only 106 were usable due to incomplete information. none of the players were absent or did not provide informed consent on the day of data collection. about 51% of the players had started to play squash between the ages of 13 and 14 years. squash injury prevalence twenty-nine per cent of players (n = 31) reported that they had sustained a squash injury within the 4 weeks prior to data collection. a total of 48 injuries were reported by the injured players. • gender differences regarding injuries. twenty-five per cent of squash injuries sustained in the 4 weeks prior to data collection were reported by females, while males accounted for 75% of the squash injuries. however the odds ratios indicated that males were not more likely to sustain more injuries than females (or 0.79, 95% confidence interval (ci): 0.31 2.2). • exposure and injury. on average, players practised twice a week for about 2 4 hours. the injury rate was calculated per 1 000 playing hours of exposure. the total exposure was calculated by totalling the total exposure hours reported by the players. considering that the 48 injuries were sustained by the 106 players, the injury rate per 1 000 hours of exposure was about 0.45 per 1 000 playing hours. table ii. sample description no. of participants females 13-14 yrs 4 15-16 yrs 17 17-18 yrs 9 males 13-14 yrs 19 15-16 yrs 39 17-18 yrs 18 sajsm vol 19 no. 1 2007 � pg3-8.indd 5 4/4/07 10:25:54 am � sajsm vol 19 no. 1 2007 • injury among club and school players. twenty-six per cent of the players played for a club while 14% played at provincial level. the results revealed a tendency for club players to sustain more injuries (41%) than school players (25% injured). the odds ratios also indicated a tendency for club players to be more at risk of injury, as the lower confidence interval was only marginally insignificant (or 0.9, 95% ci: 0.91 5.9). • pre-existing injuries. most of the injuries (32%) sustained prior to the 4-week recall were incurred while playing squash. any history of previous injury before the 4-week retrospective data collection time frame could be reported. other sports that also resulted in most of the injuries before the 4-week study period were rugby (18%) and hockey (14%), as indicated in fig. 1. there was also a tendency for players with pre-existing injuries to be more at risk for developing injuries while playing squash (or 2.28, 95% ci: 0.92 6.2) as the lower confidence interval was only marginally insignificant. • other sport participation. eighty-nine per cent of the respondents also took part in other structured sports. more than half of the players (64%) had sustained an injury while taking part in other sports before the start of the 4-week injury recall period of this study. it is notable that these injuries were not sustained within the 4 weeks prior to data collection. the most popular sports played by the study participants were hockey (49%), rugby (17%), water polo (9%) and cricket (9%). • injury location. nineteen per cent of the 48 injuries reported by the participants involved the thigh musculature. the lower back and shoulder were also commonly injured while playing squash (13%) (fig. 2). • warm-up related to injury. most of the players (93%) warmed up before play. the players preferred stretching (77%), game skills (52%) and slow jogging (40%). forty three per cent of the players who did not warm up were injured compared with 27% of players who performed a warm-up prior to playing squash. the question did not specifically ask whether subjects warmed up before the actual session in which the injury was sustained. the question assessed whether the players generally performed a warmup before playing squash. • injury mechanism. a total of 42 injury mechanisms were reported by the players. the most common injury mechanism was ‘pain without a traumatic incident’ which may be indicative of overuse type of injuries (fig. 3). • injury management. cold packs were the preferred choice of treatment (40%) applied by the players for the squash injuries. physiotherapy (35%) and rest (35%) were the other two types of treatments used most often by young squash players. discussion this epidemiological retrospective survey was conducted to ascertain the prevalence and types of squash injuries among adolescents in the western cape. the researchers support the statement of macfarlane and shanks 19 who report that only a small amount of musculoskeletal injury-related research has been done on squash players. however, the researchers found that in the relatively short study period of 4 weeks, almost one-third of the respondents reported a squash injury. in view of the short time available for the study, this indicates a relatively high prevalence of squash fig. 2. percentage of body locations injured while playing squash during the 4-week recall period. fig. 1. percentage of injuries sustained in sport prior to the 4-week study period. er s fig. 3. squash injury mechanisms. tripping and falling pg3-8.indd 6 4/4/07 10:26:12 am injuries and therefore further studies of injuries in adolescent squash players could be of high value. the thigh was reportedly the most common site of injury. injuries to the lower limb have been found to be the most common site of injury. 11 the femur significantly increases in length during growth spurts and thigh muscles including the quadriceps muscle often cannot reach the flexibility required to accommodate for the increase in skeletal growth. 14 this mismatch between bone length and muscle flexibility increases the risk of injury during challenging sporting manoeuvres that require balance and control. the high prevalence of thigh injuries among adolescent squash players signals that flexibility and neuromusculoskeletal training should be encouraged in an attempt to prevent injuries. the lower back was found to be one of the common sites of injury (13%) among these young adolescent players. this correlates with the research done by macfarlane and shanks, 19 who found that squash played a significant role in the onset and exacerbation of back pain. their study indicated that additional loading on the lumbosacral spine, which is caused by the combination of lower bending and rotation required in squash, may predispose players to back injuries. injuries can lead to musculoskeletal changes and therefore be a large predisposing factor for future back problems. 15 back injuries sustained during childhood and adolescence are also one of the most common predictors of back pain experienced during adulthood. 15 chronic back pain in adults can have economic implications associated with the increased financial burden placed on society due to the greater need for health care. 15 this early onset of back pain as well as the reduced muscle power, lower levels of co-ordination and imbalance between strength and flexibility in adolescents, 1,5 emphasises the necessity for research, preventive programmes and treatment in this area. the shoulder was also a common body region injured while playing squash (13%). squash involves repetitive overhead shoulder activity of the dominant arm in which the racquet is held. 13 strain is therefore placed on the neuromusculoskeletal structures around the dominant shoulder region and this could predispose the shoulder to overuse, instability and traumatic injuries. the research by cullen and silko 8 found that most shoulder injuries are of traumatic origin, e.g. impact against a wall, also reported to be a common injury mechanism in this study. the study findings indicate a definite tendency towards a higher injury rate if players did not warm up before play. squash is a high-intensity sport with considerable physical stress and risk of contact 6 and therefore sufficient warm-up is of the utmost importance. warm-up prepares the body for exercise. 4 possible beneficial effects include increased blood flow to the muscles, increased speed of nerve impulses, increased range of motion and decreased stiffness of connective tissue leading to the decreased likelihood of tears. 4 inadequate warm-up is seen as a training error which could result in injury. a lack of understanding of the benefits of warm-up by the coaches and players, as well as insufficient time management and effort from these two parties, could be possible reasons for the players not warming up. results showed that most players (42%) had no specific traumatic injury, but just felt pain while or after playing squash. this finding indicates that overuse may play a role in musculoskeletal injuries among squash players. this finding is in agreement with published squash epidemiological studies which also report that overuse may be a common injury mechanism in squash. 11,16 strain on the musculoskeletal system resulting in microscopic injury can lead to pain or injury if the physiological threshold of body structures is exceeded. 8 strain placed on the musculoskeletal system of adolescent squash players, coupled with general soft-tissue inflexibility make young players vulnerable to injury. 14 level of play could also possibly add to the number of injuries sustained, since club players presented with more injuries. club players usually spend more time on the squash courts and are therefore on an exposure basis alone more likely to suffer an injury. 7,18 in addition, younger players are less experienced than adults and this may further impose greater injury risk. 11 less experienced younger players often play too close to their physical opponent, do not follow the path of the ball well and are not yet well trained in correct follow-through techniques. 20 inadequate coaching and supervision of younger players, e.g. regarding sufficient warm-up also further contributes to injury risk. two-thirds of the respondents received treatment for injuries sustained during the 4-week study period. the fact that no players reported any surgical intervention and that cold packs were most often used as treatment, could indicate that injuries were not very severe or that they were not adequately managed and could therefore recur. research into the aetiology of squash injuries indicates that the most severe injuries involve the eye. 11 further research into the severity of squash injuries is necessary before any conclusions can be made concerning this. conclusion the results of the study show a high prevalence of squash injuries among adolescent squash players in the western cape. although no statistically significant results were found concerning associated factors predisposing players to such a high rate of injuries, some tendencies were identified. these include the role of warm-up and risks involved at a higher level of play, for instance among club members. detailed analysis of individual exercise parameters (e.g. body mass index, height, fitness level), an extended study period, information on the severity of injury and the exact origin or cause of injury, were identified for possible future studies. this study provided the first set of preliminary data on musculoskeletal injuries among south african adolescent squash players and serves as a baseline for future research. analysis of epidemiological injury data can assist in identifying putative risk factors which can be evaluated in the implementation of intervention programmes. sajsm vol 19 no. 1 2007 7 pg3-8.indd 7 4/4/07 10:26:12 am � sajsm vol 19 no. 1 2007 references 1. baxter-jones a, maffulli n, helms p. low injury rates in elite athletes. arch dis child 1993; 68:130-2. 2. beachy g, akau c, martinson m, olderr t. high school sports injuries. a longitudinal study at punahou school: 1988-1996. am j sports med 1997; 25: 675-81. 3. berson bl, rolnick am, ramos cg. an epidemiologic study of squash injuries. am j sports med 1981; 9:103-6. 4. brukner p, khan k. principles of injury prevention. in: clinical sports medicine. 2nd ed. sydney: mcgraw hill, 2001:84-126. 5. bylak j, hutchinson mr. common sports injuries in young tennis players. sports med 1998; 26: 119-32. 6. chard md, lachmann sm. racquet sports – patterns of injury presenting to a sports injury clinic. br j sports med 1987; 21:150-3. 7. clavisi o, finch c. striking out squash injuries – what is the evidence? injury control and safety promotion 1999; 6:145-57. 8. cullen pt, silko gj. indoor racquet sports injuries. am fam physician 1994; 50: 374-80. 9. eime r, finch c. have the attitudes of australian squash players towards protective eyewear changed over the past decade? br j sports med 2002; 36:442-5. 10. eime r, zazryn t, finch c. epidemiology of squash injuries requiring hospital treatment. inj control saf promot 2003; 10:243-5. 11. finch c, eime r. the epidemiology of squash injuries. int j sports med 2001; 2:1-11. 12. grimmer k, williams j, pitt m. reliability of adolescent self report of recent recreational injury. j adolesc health 2000; 27: 273-5. 13. gross gw. imaging. in: stanitski cl, delee jc, drez d, eds. pediatric and adolescent sports medicine. philadelphia: wb saunders, 1994. 14. gurewitsch ad, o’neill ma. flexibility of healthy children. archiv fur physikalische therapie 1944; 25: 216-21. 15. hestbaek l, leboeuf-yde c, kyvik ko. is comorbidity in adolescence a predictive for adult low back pain? a prospective study of a young population. biomedical central musculoskeletal disorders 2006; 7:29. 16. jones d, louw q, grimmer k. recreational and sporting injury to the adolescent knee and ankle: prevalence and causes. aust j physiother 2000; 46: 179-88. 17. kibler wb, safran mr. musculoskeletal injuries in the young tennis player. clin sports med 2000; 19:784-92. 18. louw ql, grimmer k, vaughan k. knee injury patterns among young basketball players in cape town. south african journal of sports medicine 2003; 15:9-15. 19. macfarlane dj, shanks a. back injuries in competitive squash players. j sports med phys fitness 1998; 38:337-43. 20. soderstrom c, doxanas m. racquetball. a game with preventable injuries. am j sports med 1982:10:180-3. pg3-8.indd 8 4/4/07 10:26:13 am original research sajsm vol 24 no. 2 2012 49 introduction the participation by children and adolescents in organised sport is increasing globally for various reasons, including enjoyment, social interaction and health.1 however, there is a risk of injury associated with participation in the activity, which varies depending on the type of activity.2 during organised events involving physical activity an accurate quantification of the risk associated with a particular activity is important to both the participant, the medical support associated with the event, and to injury epidemiologists attempting to provide guidelines to reduce this risk. of all popular team sports, rugby union (henceforth referred to as ‘rugby’) presents an above-average overall risk of injury (69 injuries per 1 000 hours exposure) to the player – greater than that of cricket (2 injuries per 1 000 hours exposure), soccer (28 injuries per 1 000 hours exposure) or even ice hockey (53 injuries per 1 000 hours exposure).3 the high incidence of injury in rugby is related to the nature of the game – a field-based team sport, with the match lasting 80 minutes (at senior levels), and characterised by short, intermittent bouts of high-intensity exercise with the 30 players having multiple contact situations throughout the game.4 risk of injury may increase with age and level/grade, which could be explained by greater speed,5,6 increased competitiveness/aggression,7,8 increased height and weight9 and increased foul play8 at higher levels of play. in rugby league, a faster, but comparable version of rugby, the incidence of injury may also increase with age, which has been attributed to a higher intensity of play at higher levels.10 rugby is popular globally, with an estimated 96 countries currently participating worldwide,4,11 and enjoys particular popularity in south africa with an estimated 400 000 500 000 players nationwide.12 the annual south african rugby union (saru) youth tournaments, which began in 1964, are a showcase of the country’s elite schoolboy rugby players at the under-13, under-16 and under-18 (two tournaments) age groups. the best 22 players from each of the country’s 14 rugby abstract background. rugby union, compared with other popular team sports, presents an above-average risk of injury to players that may increase with age and level of play. elite schoolboy rugby players have been competing at the south african rugby union (saru) youth tournaments at the under-13 (cw13), under-16 (gk16) and under-18 (aw18 and cw18) tournaments annually since 1964. the injury epidemiology of these tournaments has yet to be established. objectives. to determine the injury incidence densities (iids) and severity of saru youth week tournament injuries, if the iid increases with age, and the types of injuries at the different age group levels, in 2011. methods. all match-related injuries presenting to the tournament doctor during these tournaments were recorded and classified for severity and type, using the injury collection consensus statement for rugby. injury incidence per 1 000 match hours and 95% confidence intervals were calculated using overall player exposure time. results. match-related iids for ‘all’ (combined: 47.9 injuries/1 000 match hours) and time-loss injuries (combined: 23.1 injuries/1 000 match hours) were not significantly different by age group, despite a strong tendency to indicate differences. the absolute number of injuries per match increased with age. in general, there was a higher proportion of concussions at the gk16, aw18, and cw18 compared with the cw13 tournament(s). conclusions. time-loss iids at saru youth weeks are similar to other elite junior rugby data. the absolute number and type/ classification of injuries per match may be more informative than iids alone for medical planning purposes. s afr j sm 2012;24(2):49-54. james c brown, evert verhagen, wayne viljoen, clint readhead, willem van mechelen, sharief hendricks, mike i lambert uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, south africa, and department of public and occupational health, emgo institute for health and care research, vu university medical center, amsterdam, the netherlands james c brown, msc (med) exercise science department of public and occupational health, emgo institute for health and care research, vu university medical center, amsterdam, the netherlands evert verhagen, phd willem van mechelen, md, phd south african rugby union (saru), sports science institute of south africa, newlands, cape town, south africa wayne viljoen, bsc, ba hons (biokinetics), phd clint readhead, bsc physiotherapy uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, south africa sharief hendricks, bsc (hons) physiology mike i lambert, phd corresponding author: j brown (jamesbrown06@gmail.com). the incidence and severity of injuries at the 2011 south african rugby union (saru) youth week tournaments 50 sajsm vol 24 no. 2 2012 unions (as well as other invited teams, including neighbouring countries namibia and zimbabwe), compete for the title of unofficial winner of each tournament. for the under-18 academy week and craven week (aw18 and cw18) tournaments, there is an additional incentive to be selected for national representative teams. given the prestige associated with provincial union or national representation in south africa, these tournaments are played at a high level that is thought to be associated with a high injury incidence, based on the aforementioned literature. despite this, no accurate injury data have been collected at these tournaments since their inception in 1964. therefore, the aim of this study was to investigate the incidence and severity of the 2011 saru youth week tournament injuries, to determine differences, if any, with increasing age. a secondary aim was to explore associated factors in injured players. through the results of this investigation, it was hoped that injury prevention strategies may be enhanced at these age groups to prevent any unnecessary injuries at future tournaments. methods written informed consent to analyse the recorded information was provided by the player, or by the player’s parent or guardian if the the player was younger than 18 years of age. if, in the former case, the player was unable to sign the form owing to the nature of the injury, verbal consent was received after explaining the nature of the study. all of the injured players’ information was recorded on a saru database and the authors were subsequently granted access to this database for analysis in 2011 by saru and the uct human research ethics committee. injury surveillance was conducted on the 1 804 players (82 teams with 22 squad members) at the four saru youth week tournaments: craven week under-13 (cw13), grant khomo week under-16 (gk16), academy week under-18 (aw18) and craven week under-18 (cw18), which took place during june and july 2011. a saru-appointed tournament doctor (td) was available at each tournament to assess any injury complaint that a player may have had. all injuries that happened before the official tournament matches were not included in the analyses. because of the compact schedule of these tournaments, the non-match training hours contributed relatively little to overall tournament exposure and non-match injuries were therefore not recorded. an injury collection form was designed based on the consensus statement for injury surveillance.10 demographic information of each injured player, such as the player’s team, body height, body weight, age, whether or not the player had medical aid (insurance), and protective gear at the time of the injury, was also collected. unfortunately, this information was not available for players who were not injured. exposure time was calculated based on the injury collection consensus statement for rugby:13 nm x pm x dm (where is nm is the number of matches, pm is the number of players per match, and dm is the duration of the match in hours). owing to the fact that the injury surveillance was conducted on all the teams in the tournament, pm was calculated as 30 (15 players per team) for each match. it was also assumed that there were 30 players for the entire match, thereby ignoring the effects of yellow and red cards on match exposure.10 injury definition the injury definitions, described in the rugby injury consensus statement,13 were adapted to the following to suit the needs of these tournaments: ‘any physical complaint, which was caused by a transfer of energy that exceeded the body’s ability to maintain its structural and/or functional integrity, that was sustained by a player during a rugby match and required attention from the saru tournament doctor (td), irrespective of who decided this’. injury severity highly qualified paramedics and/or nursing staff were available at all tournament matches and therefore, for a player to consult with a td, the injury would have to be one that the paramedics/nurses could not deal with. a time-loss injury was an injury (based on the aforementioned definition) that resulted in being absent more than one match in a tournament, or more than one day of normal/planned recreational activities after the tournament. injury type the ‘type’ of injury categories were collapsed from the original definition for the saru tournaments so that each injury was classified, according to the td, as relating to one of the following: concussion, spinal cord, broken bone/fracture, joint/ligament/tendon, muscle, bruise, laceration (including skin abrasion), other, unsure. match days match days (ms) are defined as days on which all teams played an official tournament match on the same day. for cw18, when only half the teams played in an alternating fashion for the first four days, one m would span two days to include all the team matches. however, for the purpose of comparing the daily load on the tournament medical staff, a tournament match day (tm) is defined as any day in which official rugby matches were played. a tm could also be a m. these terms should be contrasted to ‘rest days’ (rs), on which teams were able to do what they wanted. exposure was only calculated from ms, and not rs. the recording of information was performed at all tournaments by either jb or sh to reduce internal inconsistencies. owing to the short duration of these tournaments (4 5 days), only a small number of players were injured a second time (n=4) and therefore these second injuries were analysed with the first injuries. it has been suggested that only injuries severe enough to be considered time-loss injuries (see ‘injury definitions’) should be reported for uniformity of injury comparisons.13 however, because of the relatively short duration and corresponding low absolute injury numbers at these tournaments, which would make further analyses and interpretation difficult, ‘medical attention’ and ‘unsure’ injuries were also reported for this study. suspected time-loss injuries were followed up either at the tournament or at weekly intervals after the conclusion of the tournament to confirm the severity of injury: when the player was able to return to normal sporting activities or stopped all treatment. statistical analyses exposure was calculated as the total number of team matches played (varied by tournament, table 1) multiplied by the number of players per match (30 in each case) multiplied by the match duration in hours (varied by tournament, table 1).13 for clarity: when two teams were competing against each other, as occurred for every tournament match, this was considered one team match. injury incidence densities (iids) and corresponding 95% confidence intervals (95% cis) were calculated for the number of injuries (regardless of whether one person was injured more than once) per 1 000 hours of match play.14 incidences, including their 95% cis, which did not overlap were considered to be significantly different from each other. sajsm vol 24 no. 2 2012 51 results key tournament descriptive information for the four youth week tournaments is provided in table 1. the match duration increased with age, from two 20-minute halves (total match duration = 40 minutes) at under-13 to two 35-minute halves (total match duration = 70 minutes) at under-18 level. although cw18 was the only five-day tournament, this tournament structure was unique in that only half of the teams (10 teams, five matches) played per day, in an alternating fashion, until the final match day in which all 20 teams competed (10 matches). the other three tournaments (cw13, gk16 and aw18) had each team play every day, with a rest day before the final day of the tournament, in which all teams played. therefore, cw13 had the greatest number of ms (n=4), while the other tournaments had three. the number of teams at each tournament was also greatest at the under-18 tournaments, although, owing to cw13 having four ms as opposed to the three in the other tournaments, the youngest age-group tournament also had the second highest number of overall matches. the under-18 tournaments had a greater overall exposure time because of the longer duration of their matches. in total, there were 1 804 players at risk for 3 945 hours of match injury exposure (exposure based on consensus statement calculations10) for all of the saru youth week tournaments (fig. 1). of these players, 185 sustained an injury during a tournament match-related incident and were attended to by the td. four players suffered two injuries during the tournaments. based on the td’s estimation, 91 injuries were considered severe enough to be classified as time-loss injuries. the remaining 98 injuries comprised 87 medical attention injuries and 11 injuries for which the td was unsure of the diagnoses and the players could not be followed up. the majority (81%) of the 91 estimated time-loss injuries were confirmed telephonically one week after each tournament. the combined iid of time-loss injuries was 23.1 injuries per 1 000 match hours (95% cis: 18.3 27.8) across all the tournaments, while the overall iid was 47.9 injuries per 1 000 exposure hours (95% ci: 41.1 54.7). cw13 had the lowest iid of time-loss injuries (15.3 injuries per 1 000 exposure hours; 95% ci: 6.2 24.3), whereas cw18 had the highest iid of time-loss injuries (28.6 injuries per 1 000 exposure hours; 95% ci: 18.3 38.8) (fig. 2). the overall iid (all injuries), and the iid of time-loss injuries, tended to increase with age, although there were no statistically significant differences between tournaments for either overall or time-loss iids. injuries per match, injury severity and type the oldest age-group tournaments (aw18 and cw18) had the highest absolute number of injuries per match (table 2). these two tournaments also had the highest absolute number of time-loss injuries per match. among the youngest age group (cw13), muscle injuries accounted for the greatest proportion of injuries, while joint/ ligament/tendon injuries were consistently over-represented at the three older age tournaments (gk16, aw18 and cw18). there was a relatively high proportion of lacerations/skin abrasions that led to time loss; two injuries to a mouth (one tongue laceration and one case of multiple tooth loss), three eye-lid lacerations and two deep head wounds. medical insurance and protective equipment use twenty-four per cent (n=41) of the 174 injured players who answered the question had no medical insurance for their injuries. of the players who suffered a time-loss injury, 22% (n=19) reported having no medical insurance. only 57% (n=107) of all injured players were wearing a mouth guard at the time of their injury. similarly, of the players who suffered a time-loss injury, only 51% (n=46) were wearing a mouth guard at the time of their injury. discussion the main finding of this paper was that the iids of injuries (overall and time loss) during the saru youth week tournaments did not differ significantly by age in 2011, rejecting our initial hypothesis. however, there was a strong tendency for the absolute number and relative proportion of time-loss injuries to increase with increasing age group (proportion of time loss to all injuries: cw13 – 36%; gk16 – 43%; aw18 – 49%; cw18 – 58%). haseler et al.15 reported similar time-loss injury incidences in age groups that were comparable with those investigated in the current study and lower than those at elite under-20 level.16 overall, muscle and joint/ligament/tendon injuries were the most common types of injuries, which is comparable with the table 1. descriptive details of the four south african rugby union (saru) youth week tournaments, 2011 tournament teams (n) duration (min) matches (n) exposure (hours) structure iid (95% ci) time-loss iid (95% ci) cw13 18 40 36 720 m,m,r,m,m 43.1 (27.9 58.2) 15.3 (6.2 24.3) gk16 18 60 27 810 m,m,r,m 45.7 (31.0 60.4) 19.8 (10.1 29.4) aw18 26 70 39 1 365 m,m,r,m 50.5 (38.6 62.5) 24.9 (16.5 33.3) cw18 20 70 30 1 050 tm,tm,tm, tm,r,m* 49.5 (36.1 63.0) 28.6 (18.3 38.8) cw13 = craven week under-13; gk16 = grant khomo under-16; aw18 = academy week under-18; cw18 = craven week under-18; m = match day; r = rest day; iid = injury incidence density (injuries/1 000 hours exposure). * for the first four days, only half of the teams play each day in an alternating fashion, and are therefore represented as tournament match days (tms). all the teams play on the final day, therefore there are five tds, one of which is a match day (m) by definition (see methods section). 52 sajsm vol 24 no. 2 2012 elite under-20 level previously studied16 and junior rugby league,17 but not community-level junior rugby.15 this lack of significant differences between age group iids, particularly those of the time-loss injuries, are in contrast to findings consistently reported in the literature. these conflicting reports are from early5-8 and more contemporary literature,9,15 collected and reported on using the consensus statement for injury surveillance in rugby.13 both contemporary studies9,15 took place over a longer time period (former = three-week tournament; latter = nine-month season) than this study. despite the fact that the wearing of mouth guards was highly recommended in the team manager’s handbook, only 51% of players who suffered a time-loss injury were wearing a mouth guard at time of their injury. this phenomenon does not appear unique to south africa as similarly low compliance has been reported in northern italy.18 although the literature on mouth guard effectiveness in injury prevention is equivocal about concussion,19 there is evidence to suggest that dental claims can be reduced with improved compliance of mouth guard wearing.20 because of the relatively small number of time-loss injuries in this study, further comparisons between tournaments for positions or phases of play (scrum, ruck, tackle) could not be facilitated, as knowles et al.14 stated that cis become inaccurate and therefore of little use to the researcher when calculated on raw data of five or less. however, the proportion of concussions of all time-loss injuries at the tournaments of older groups (gk16, aw18 and cw18) was high and should be focused on in future years. these youth tournament formats (table 1) may not be unique internationally and, therefore, raise the question of whether the consensus statement,13 suggested for all rugby injury surveillance studies, should consider broadening the definition of injury that should be reported, particularly for short-format tournaments such as the ones presented in this study. furthermore, injury incidence densities alone may not have as much practical relevance for prospective medical professionals involved in providing medical support and infrastructure at these type of rugby tournaments. importantly, this study reports only one year of data collection and therefore may not be a true reflection of these tournaments, emphasising the importance of continued injury surveillance at future saru tournaments. of concern is that 22% of the players who suffered time-loss injuries, had no medical aid cover for the ongoing treatment of their injuries. although financial situations vary by rugby union, all competing teams should attempt to ensure that all their players are covered by medical aid or have some financial support structure in fig. 1. flow diagram indicating the number of players injured at the 2011 saru youth weeks according to the injury definitions. the severity of injury was estimated by the tournament doctor (td) in each case; these were subsequently confirmed telephonically. fig. 2. incidence (+/95% cis) of time loss (white bars) and all (time loss are included in all) injuries at each south african rugby union (saru) tournament in 2011. cw13 – craven week under-13; gk16 – grant khomo under-16; aw18 – academy week under-18, cw18 – craven week under-18. fig. 3 (a). injury incidence density (iid) (+/95% cis); and (b): injuries per match day (m) of all injuries (medical attention, timeloss and unsure) and time-loss injuries only (white area) at each south african rugby union (saru) tournament in 2011. (cw13 – craven week under-13; gk16 – grant khomo under-16; aw18 – academy week under-18; cw18 – craven week under-18. tournament match days cw13: 4; gk16: 3; aw18: 3; cw18: 5. note that cw18 has three m, but five actual tournament match days (tm).) sajsm vol 24 no. 2 2012 53 place for their participating players in case of a medical emergency, prior to competing in future tournaments. a limitation of our study was the large reliance on the td’s clinical judgement for diagnosing severity and type of injury at each tournament; this could potentially compromise the level of comparability between tournaments. while all time-loss and ‘unsure’ injuries were followed up telephonically after the tournament, medical attention injuries were assumed to be accurately defined by the td. inaccurate diagnoses could have resulted in under-reporting of time-loss injuries. secondly, although it would be in direct contrast to saru’s player safety mandate, some teams may have ‘hidden’ injuries from the td owing to the short nature of the tournaments. also, players were less likely to report injuries to the td on the final day of the tournament as they may have preferred to see their family physician (families on medical aid would not need to pay for these services). thirdly, the lack of quantification of training time and injuries before and during the tournament was a further limitation, but was logistically difficult to measure. practical implications of the current study the current article could be used as a reference for prospective tds and support personnel involved in the medical planning and management of future saru youth week tournaments, or any other tournaments with similar, compact structures. iids, in isolation, may be misleading for prospective tds for planning purposes. for example, with reference to fig. 3a, which displays iids, prospective tds could interpret the medical management loads of the two under-18 tournaments to be comparable. however, fig. 3b accurately illustrates the greater tm medical burden placed on the aw18 compared with the cw18 td, despite both teams having the same number of ms (n=3) according to the definition. despite the same number of ms and a similar number of injuries per match (table 2), the cw18 tournament structure is less compacted, has fewer overall teams and therefore less matches than aw18. as the first four days of cw18 only has half the teams participating, this adds to the reduced medical load on the td. the data presented in the suggested consensus format alone do not accurately guide the infrastructure and personnel requirements for these tournaments. this could have huge practical implications regarding effective planning around budget spend, and medical staffing and infrastructure requirements for these tournaments. therefore, for medical planning purposes, it is suggested that the data in tables 1 (daily tournament format) and 2 (injuries per match) are used in combination to determine and cater appropriately for the estimated number, severity and types of injuries per day at each tournament. the tournament should be planned based on the known absolute number of injuries per match (table 2), with particular reference to time-loss injuries that tend to require longer treatment and diagnostic times. for example, the recommended assessment and treatment of a concussion using the sports concussion assessment tool (scat2) card21 takes approximately 30 minutes for the td to administer properly. with two, or three, concurrent matches being played at the under-18 age groups, the td would become overwhelmed and would potentially compromise optimal treatment. a simple practical guide for future planning of these tournaments would be to allocate one td per time-loss injury per match. therefore, the under-18 tournaments would require one td per match, while the tds of the under-13 and under-16 age groups could cope with one td, with two matches being played concurrently. conclusion the injury incidences of both all and time-loss injuries were not significantly different between age groups at the 2011 saru tournaments. this finding is contrary to contemporary literature and our initial hypothesis, but is probably explained by the short duration of the saru tournaments. however, the saru tournament structures/ formats may not be unique, and therefore the consensus statement for injury collection should be adapted to include reporting of a broader definition of injuries. furthermore, while injury incidences of timeloss injuries may be scientifically comparable, in isolation they may table 2. number of injuries per match in south african rugby union (saru) youth tournaments, 2011. (the number of matches per day is indicated in parentheses after the tournament title. time-loss (tl) injuries are reported separately and as part of the ‘all’ injuries category. the proportions of the different types of injuries, as diagnosed by the td, are shown below the number of injuries per match.)   cw13 (n=9) gk16 (n=9) aw18 (n=13) cw18 (n=5 or 10)* injury severity tl all tl all tl all tl all injuries per match, n 0.3 0.9 0.6 1.4 0.9 1.8 1.0 1.7 type of injury, % concussion 18 10 38 17 38 19 13 8 contusion 9 26 6 3 6 13 10 21 fracture 18 6 6 3 12 6 3 2 joint/ligament/tendon 18 19 44 31 29 32 47 37 lacerations † 9 3 0 14 3 9 17 25 muscle 27 29 6 14 6 16 0 0 unsure/other 0 6 0 19 6 6 10 8 cw13 = craven week under-13; gk16 = grant khomo under-16; aw18 = academy week under-18; cw18 = craven week under-18; all = all injuries; tl = time-loss. * tournament structure of cw18 is different to other tournaments in that the final match day has double the amount of matches than the preceding four days. this is explained in detail in the ‘results’ section. † includes skin abrasions. 54 sajsm vol 24 no. 2 2012 be misleading from a medical planning or evaluation perspective. presenting absolute numbers of injuries (both time-loss and medical attention) per match, in conjunction with injury incidences,13 may satisfy more stakeholders in gaining practical application from injury surveillance reports. conflict of interest. the authors have no conflict of interest to declare. funding was provided by the nrf/vrije university desmond tutu doctoral fund (jb), daad scholarship (sh) and the south african rugby union (saru). acknowledgements. the authors would like to thank the medical staff at all of these tournaments for their invaluable assistance with the injury data collection: all the nurses and paramedic staff at each of the tournaments as well as the tds: dr deon van tonder, dr malebo mokotedi, dr andrea burmeister and dr patho cele. the authors would also like to thank saru for commissioning this injury surveillance project. references 1. allender s, cowburn g, foster c. understanding participation in sport and physical activity among children and adults: a review of qualitative studies. health educ res 2006;21(6):826-835. [pmid: 16857780] 2. van mechelen w, hlobil h, kemper hc. incidence, severity, aetiology and prevention of sports injuries. a review of concepts. sports med 1992;14(2):82-99. [pmid: 1509229] 3. fuller c, drawer s. the application of risk management in sport. sports med 2004;34(6):349-356. [pmid: 15157119] 4. duthie g, pyne d, hooper s. applied physiology and game analysis of rugby union. sports med 2003;33(13):973-991. [pmid: 14606925] 5. roux ce, goedeke r, visser gr, van zyl wa, noakes td. the epidemiology of schoolboy rugby injuries. s afr med j 1987;71(5):307-313. [pmid: 3563755] 6. nathan m, goedeke r, noakes td. the incidence and nature of rugby injuries experienced at one school during the 1982 rugby season. s afr med j 1983;64(4):132137. [pmid: 6867888] 7. lee aj, garraway wm. epidemiological comparison of injuries in school and senior club rugby. br j sports med 1996;30(3):213-217. [pmid: 8889113] 8. bird yn, waller ae, marshall sw, alsop jc, chalmers dj, gerrard df. the new zealand rugby injury and performance project: v. epidemiology of a season of rugby injury. br j sports med 1998;32(4):319-325. [pmid: 9865405] 9. fuller cw, molloy mg. epidemiological study of injuries in men’s international under-20 rugby union tournaments. clin j sport med 2011;21(4):356-358. [pmid: 21617525] 10. gabbett tj. incidence of injury in junior and senior rugby league players. sports med 2004;34(12):849-859. [pmid: 15462615] 11. quarrie kl, hopkins wg. tackle injuries in professional rugby union. am j sports med 2008; 36(9):1705-1716. [pmid: 18495967] 12. sa rugby. boksmart website: www.boksmart.com (accessed 3 and 16 march 2011). 13. fuller cw, molloy mg, bagate c, et al. consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union. br j sports med 2007;41(5):328-331. [pmid: 17452684] 14. knowles sb, marshall sw, guskiewicz km. issues in estimating risks and rates in sports injury research. j athl train 2006;41(2):207-215. [pmid: 16791309] 15. haseler cm, carmont mr, england m. the epidemiology of injuries in english youth community rugby union. br j sports med 2010;44(15):1093-1099. [pmid: 20961921] 16. fuller cw, molloy mg, marsalli m. epidemiological study of injuries in men’s international under-20 rugby union tournaments. clin j sport med 2011;21(4):356358. [pmid: 21617525] 17. gabbett tj. incidence of injury in junior rugby league players over four competitive seasons. j sci med sport 2008;11(3):323-328. [pmid: 17698413] 18. boffano p, boffano m, gallesio c, roccia f, cignetti r, piana r. rugby athletes’ awareness and compliance in the use of mouthguards in the north west of italy. dent traumatol 2011;28(4):210-213. [pmid: 21967600] 19. navarro rr. protective equipment and the prevention of concussion what is the evidence? curr sports med rep 2011;10(1):27-31. [pmid: 21228647] 20. quarrie kl, gianotti sm, chalmers dj, hopkins wg. an evaluation of mouthguard requirements and dental injuries in new zealand rugby union. br j sports med 2005;39(9):650-651. [pmid: 16118304] 21. mccrory p, johnston k, meeuwisse w, et al. summary and agreement statement of the 2nd international conference on concussion in sport, prague 2004. br j sports med 2005;39(4):196-204. [pmid: 15793085] original research 76 sajsm vol. 27 no. 3 2015 background. the cricket pace bowler utilises various strategies, including a more extended front knee angle, to achieve optimal performance benefits. at times this is done to the detriment of injury prevention. objective. to investigate the relationship between three-dimensional (3d) knee kinematics during pace bowling action, injury incidence and bowling performance at the start and end of a cricket season. methods. knee angle and ball release (br) speed of injury-free premier league (club level) cricket pace bowlers over the age of 18 years were measured at the start and end of the cricket season. kinematic, injuryand bowling performance-related (br speed and accuracy) data were analysed using paired and independent student’s t-tests, pearson’s correlation coefficient, χ2 test and a two-way analysis of covariance with repeated measures. results. thirty-one bowlers participated in this study, and kinematic data of a subset of 17 were analysed. nine bowlers (53%) sustained injuries during the cricket season. no statistically significant relationship was found between knee angle and injury. bowlers who did not sustain an injury bowled with more knee flexion at the start of the season (mean (standard deviation) 157.07˚ (12.02˚)) than at the end of it (163.95˚ (6.97˚)) (p=0.01). there was no interaction between accuracy and knee angle. there was a good to excellent inverse correlation between br speed and knee angle among bowlers who remained injury free (r=–0.79; p=0.18). conclusion. bowlers who remain injury free during the course of the season may use strategies other than the front knee angle to facilitate high br speeds. technique-related variables which are more ‘protective’ against injuries while allowing for higher br speeds should be further investigated among bowlers. s afr j sports med 2015;27(3):76-81. doi:10.7196/sajsm.8111 cricket pace bowling: the trade-off between optimising knee angle for performance advantages v. injury prevention b olivier,1 phd; a v stewart,1 phd; a c green,2 msc (physiol); w mckinon,2 phd 1 department of physiotherapy, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 school of physiology, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: b olivier (benita.olivier@wits.ac.za) ball release (br) speed and bowling accuracy are two variables that contribute to the performance of a cricket pace bowler. a batsman has only a few milliseconds to judge the flight of the ball if a high br speed is successfully achieved. in addition to high br speeds, if a pace bowler can predict the pitch of the ball, such accuracy affords him a useful tool which allows him to strategically plan dismissal of a batsman.[1] the strain applied to a bowler’s body to facilitate greater br speeds and accuracy are known to predispose the bowler to injury. [2,3] therefore the optimisation of bowling performance and prevention of injury are necessary among cricket pace bowlers. the relationship between technique-related three-dimensional (3d) kinematics of the pace bowling action and br speed has been widely investigated in once-off cross-sectional studies. front knee angle during the delivery stride of the pace bowling action has been associated with higher br speeds.[4,5] in addition, a more extended knee contributes to higher br speed by increasing the radial distance between front foot contact and the extended bowling arm, which results in a greater tangential endpoint velocity.[6] however, there is still controversy around the relationship between br height and br speed.[5] studies investigating the association between bowling accuracy and technique-related variables are scarce.[7,8] in addition to studies investigating br speed, a few have investigated the association between front knee angle and injur y, and found that a more extended knee during the power phase of the pace bowling action, when ground reaction forces are exceptionally high, is associated with injury.[9,4,2] the interrelationship between proximal (lower back) and distal body segments (knee) has been confirmed by crewe et al.,[3] who found an association between a more extended front knee during the front foot contact phase and lumbo-pelvic shear forces. since lower quarter injuries, lower back and lower limb injuries are extremely common in pace bowlers,[10-12] the investigation of lower quarter injuries may provide useful insights. the comparison of kinematics at the start and at the end of the season, and between injured and non-injured players may give valuable information on the cause and effect of knee kinematics during bowling action. the rarity of longitudinal studies assessing technique-related variables and their possible contribution to speed and accuracy prompted this study. therefore the aim of this study was to investigate the relationship between 3d knee kinematics during the pace bowling action, injury incidence and bowling performance at the start as well as at the end of a cricket season. methods study design, setting and participants this is a descriptive study with a longitudinal component. data collection took place at the university of the witwatersrand’s indoor sajsm vol. 27 no. 3 2015 77 cricket nets. premier league cricket pace bowlers playing for cricket clubs in south gauteng province, south africa, were randomly invited to participate in this study. injury-free pace bowlers over the age of 18 years were included in this study. bowlers who have undergone previous surgery to the spine or limbs were excluded from this study. a pace bowler was defined as a bowler bowling at a speed of 120 km/h or more,[12] and who averaged more than five overs bowled in matches played during any of the previous two seasons.[13] injury surveillance injuries (status, nature and prevalence) were monitored monthly through use of a standardised (self-reporting) questionnaire[14] throughout the duration of the cricket season. the self-report injury questionnaire enquired on the status, nature, mechanism and management of injuries. an injury was defined as a ‘musculoskeletal condition that resulted in loss of at least one day of sporting activity or that occurred during a sporting activity that required medical attention or which forced the bowler to quit the activity’.[14] bowling performance: br speed and accuracy br speed was captured at the start and end of the season using a handheld radar gun (stalker ats, usa) positioned 180˚ behind the br point.[5] classification of bowlers according to speed was as follows: medium pace (120 129 km/h); medium fast pace (130 139 km/h) and fast pace (≥140 km/h).[12] bowling accuracy was assessed according to a categorical scale measuring the ability of the bowler to pitch the ball in two target blocks, namely a marked target on the pitch (fig. 1)[1] and a target behind the stumps (fig. 2).[7] if a bowler pitched the ball in none, one or both of the two target blocks, he obtained a score of 0, 1 or 2 out of 2 respectively.[7,1] each bowler bowled with a new 156 g cricket ball (kookaburra sport ltd, south africa). instrumentation and set-up kinematic analysis considered three dimensions: length, breadth, and depth. kinematic variables were assessed at the start and the end of an 8-month cricket season. kinematic data were captured using five high-speed digital cameras (pixelink pl-a741, usa) which recorded at 85 frames per second. cameras were positioned around a capture volume of 12.76 m long, 4.25 m wide and 2.08 m high. a mean in line with leg stump (to accommodate land r-handed bowler) r-handed batsman in line with wide mark 6 m from batsman 2 m w id e good length accuracy target 4 m from batsman bowler 20 .1 2 m le n g th 3.05 m width fig. 1. accuracy target on the pitch. 35 cm width 50 cm above �oor batsman 25 cm outside o� stump accuracy target 10 0 cm le n g th fig. 2. accuracy target behind the stumps. 78 sajsm vol. 27 no. 3 2015 (standard deviation (sd)) residual error of marker position of less than 1.2 (0.7) mm was found. procedures a pilot study was done with five bowlers whose data were not included in the main study due to minor changes to instructions to bowlers and order of data collection procedures. bowlers first warmed up in their own accustomed manner, which included the opportunity to bowl six practice balls. light-reflective markers were attached with double-sided adhesive tape to predetermined anatomical landmarks, as well as to the ball (fig. 3). each participant bowled six match-pace deliveries aimed at a right-hand batsman while being recorded. for each attempt br speed and accuracy were measured. ethical considerations written informed consent was required and confidentiality was ensured. ethical approval was obtained from the university of the witwatersrand human research ethics committee. data reduction and statistical analysis the power phase was defined from front foot placement (ffp) to br.[2] ffp was identified as the first frame when the front (nondominant) toe marker reached its lowest position. br was defined as the first frame observed where the ball was no longer in contact with the bowler’s hand.[5] all data for left-hand bowlers have been converted to read as data for right-hand bowlers for analytical standardisation. the delivery that obtained the highest accuracy score in conjunction with the fastest br speed was used for kinematic analysis of variables. bowlers who sustained a lower quarter (lower back and lower limb) injury during the cricket season under review are referred to as ‘injured’, and those who remained injury free are referred to as ‘non-injured’. only non-contact injuries were included in the analysis. data collected at the start of the season were referred to as preseason data and those collected at the end of the season as postseason data. knee angles were classified into four different groups (basic classification), depending on the angle at ffp and br (table 1). knee-angle classification categories were modified from those described by bartlett et al.[6] and portus et al.[4] statistical analysis was conducted using spss version 22 (ibm, usa) using a twoway repeated measures analysis of covariance (ancova) with an alpha level of 0.05. there were two primary factors (ffp knee angle and br knee angle), each with two levels (pre season and post season). the categorical variables, such as injury and accuracy, were calculated as between-subjects factors, while the other continuous variable (the average speed preand postseason) was calculated as a covariate. additional analysis, namely paired-sample and independent t-tests when there were categorical variables and linear regression for purely continuous variables, were conducted to further investigate these interactions. pearson’s product moment correlation coefficient (r) was used to identify relationships between continuous variables (kinematic variables and br speed). qualitative descriptions for the strength of the relationships were used to contextualise the relationships between continuous variables as follows: r=0.00 0.25 (little or no l heel ball marker l shoulder l elbow lat. l elbow med. l psis l �nger l thigh l knee lat. l knee med. l tibia l ankle c7 r toe r asis clavicle l toe l asis sternum r heel r ankle r tibia r knee med. r knee lat. r thigh r �nger sacrum r psis l1 t10 t7 r shoulder fig. 3. predetermined anatomical landmarks for marker placements. (r = right; l = left; psis = posterior superior iliac spine; asis = anterior superior iliac spine.) table 1. knee angle (°) classification category* basic classification further classification knee angle at ffp knee angle at br knee angle at ffp knee angle at br flexor <170° <170° or = ffp flexor + <170° (e.g. 158°) < ffp (e.g. 146°) flexor – <170° (e.g. 158°) > ffp (e.g. 168°) flexor-extender <170° (e.g. 146°) ≥170° (e.g. 174°) extender ≥170° (e.g. 174°) ≥170° or = ffp extender + ≥170° (e.g. 174°) > ffp (e.g. 178°), or into hyperextension extender – ≥170° (e.g. 174°) < ffp (e.g. 170°) extender-flexor ≥170° (e.g. 174°) <170° (e.g. 146°) *descriptions are based on a reference position of a straight leg (180°). sajsm vol. 27 no. 3 2015 79 relationship); r=0.26 0.50 (fair relationship); r=0.51 0.75 (moderate to good relationship); and r>0.75 (good to excellent relationship).[15] a χ2 test was used to analyse the relationship between knee-angle classification category and accuracy (categorical data). results participants and injury incidence thirty-one fast, fast-medium and medium pace bowlers between the ages of 18 and 26 years (mean (sd) 21.8 (1.8) years) par ticipated in the study. twenty-six participants were right-handed and five were left-handed bowlers. sixteen bowlers sustained one or more injuries during the course of the 8-month cricket season. all injured pace bowlers sustained at least one lower back and/or lower limb injury during the season as a direct result of the pace bowling action. injuries comprised four lower back, four buttock and groin, two hamstring, four knee, one shin and four ankle injuries. knee angle, injury incidence and bowling performance owing to missing kinematic data, case-wise deletion of missing data was performed, and 14 bowlers were removed from the analysis. analysis was performed on the remaining 17 bowlers, of whom eight were from the non-injured group and nine from the injured group. descriptive statistics for knee angle and br speed are shown in table 2. no statistically significant difference between preseason and postseason knee angle for the group as a whole was found for knee angle at ffp (p=0.30) or at br (p=0.17). average br speed for the group was similar at the start and end of the season (p=0.26). no statistically significant relationship was found between knee angle and injury ( a n c ova ) . s t at i s t i c a l l y s i g n i f i c a nt within-subjects interactions were found between knee angle, br speed and accuracy (ancova) (table 3). paired t-tests revealed no st at ist ic a l ly sig nif ic ant dif ference between knee angle as measured at the start of the season and knee angle at the end of the season in the injured group. however, a difference was found among bowlers who remained injury free during the course of the season, between the preseason knee angle of 157.07° (12.02°) and postseason knee angle of 163.95° (6.97°) in the ffp position of the bowling action (p=0.01). most bowlers were successfully able to hit both of the accuracy targets (fig. 4). the majority of bowlers were from the flexor classification category (n=15), while one was classified as flexor-extender and one as extender. there was no interaction between accuracy and mean knee angle or between accuracy and knee-angle classification. there was a good to excellent inverse correlation between br speed and knee angle in the noninjured group (r =–0.79; p=0.18) (fig. 5). no correlation was found between br speed and knee angle for the injured group or the group as a whole. discussion the objective of this study was to investigate the relationship between 3d knee kinematics, injury and bowling performance-related variables. the findings give useful insights into the role of a technique-related intrinsic factor in injury, br speed and bowling accuracy. table 2. knee angle (°) and br speed (m/s) at the start and end of the cricket season, mean (sd) variable pre season post season non-injured (n=8) injured (n=9) total (n=17) non-injured (n=8) injured (n=9) total (n=17) knee angle at ffp (°) 157 (12) 161 (8) 159 (10) 164 (7) 160 (11) 161 (9) knee angle at br (°) 143 (21) 140 (21) 141 (20) 138 (18) 127 (16) 132 (17) br speed (m/s) 122 (6) 125 (7) 123 (7) 122 (8) 116 (24) 119 (18) post season 2/2 targets 16 speci�c accuracy pre season 0/2 targets 1/2 targets 0 2 4 6 8 10 12 14 0 2 10 14 7 1 b o w le rs , n fig. 4. accuracy scores as measured at the start and end of the cricket season (n=17). table 3. statistically significant interactions between knee angle at ffp and br bowling positions, br speed and accuracy (n=17) source of variance (within subjects)* df ss f p knee angle at ffp × knee angle at br × br speed 1 775.436 7.068 0.029 knee angle at ffp × knee angle at br × accuracy post season 2 1 060.018 4.831 0.042 knee angle at ffp × knee angle at br × accuracy pre season 1 641.323 5.846 0.042 knee angle at ffp × knee angle at br × accuracy pre season × accuracy post season 1 634.264 5.781 0.043 error 8 1 591.272 df = degrees of freedom; ss = sum of squares. *the within-subjects effect and interaction of the repeated measure with independent variables; the between-subjects was computed for the independent measure, knee angle, and is not shown here owing to not being significant. 80 sajsm vol. 27 no. 3 2015 the definition of injur y used in this study is different to the current definition recommended for use in international injury surveillance.[13] the recommended definition, which is currently under review, includes only match time-loss injuries, while the definition of injury used in this study was less stringent and allowed for less severe injuries to be identified. it is important to identify musculoskeletal injuries of all levels of severity because an injury which may not be severe enough to cause match time loss, may worsen if not identified early on. also, only non-contact injuries sustained to the lower quarter – lower back and or lower limb – were included in the analysis of this paper which strengthens the findings, as it is specifically the non-contact injuries which can be influenced by technique modification. as the knee angle was studied, we preferred to focus only on lower back and lower limb injuries due to the distribution of force throughout the kinetic chain. [2,3] in this study the ancova did not identify injury status as statistically significant in the interaction with knee angle, which means there was no difference between mean knee angle in the injured v. the non-injured group. however, although no statistical difference was found in the injured group between knee angle measured at the start of the season compared with at the end of the season, the bowlers who did not sustain an injury during the season bowled with a more flexed knee at the start of the season compared with at the end of it. it may be that these bowlers who remained injury free were able to protect their lower back and lower limbs against injury by bowling with a more flexed knee. this is most probably due to better dissipation of ground reaction forces by a flexed limb.[4] a straighter knee at front-foot impact is associated with injury due to the increase in impact forces[2,3] and a decrease in time to peak force.[6] overuse and/or microtrauma during the season may affect the ability to bowl with a more flexed leg, because of generalised muscle fatigue. for example, portus et al.[4] found that increased trunk stability is associated with ability to bowl with a more flexed leg. if trunk stability is affected during the season due to spinal microtrauma suffered as a result of the high-load repetitive bowling action,[2] this may affect the knee angle by the interconnectedness of the trunk and lower limbs. thus, the influences on one end of the kinetic chain may affect changes in another.[16] this accumulation of microtrauma, possibly due to overtraining among all bowlers, may also explain the finding that non-injured bowlers bowled with the knee at an angle similar to the injured bowlers at the end of the season, although the non-injured bowlers bowled with a more flexed knee at the start of the season. in this study most bowlers formed part of the flexor category (table 1), which means that they landed on a relatively flexed knee (in this case an angle of approximately 160°) and then flexed their knees a further 10°. similar findings were observed by wormgoor et al.[5] bartlett et al.[6] described this as a ‘collapse’ of the lower limb where the bowler may experience the injury-protective benefits of force attenuation due to the flexed limb, but not the apparent bowling-performance benefits associated with a straighter limb.[6,4] however, in this study the opposite was true, where a correlation between a more flexed knee and higher br speeds was found among non-injured bowlers (fig. 5). no link between knee-classification categories and bowling performance (br speed and accuracy) could be established due to the small numbers of bowlers in the flexor-extender and extender knee-classification categories. no correlation was found between knee angle and br speed for the group as a whole. controversy exists in the literature with regard to the role of the front knee angle and br speed.[7,4,5] wormgoor et al.[5](r=0.52; p=0.005) and portus et al.[4] (2004) (r=0.37; p=0.02) found statistically significant, although moderate to low correlations between a front knee angle and br speed, while portus et al.[7] (2000) did not find a statistically significant correlation. the sample sizes of those studies which indicated a statistically significant correlation were 28[5] and 42[4] bowlers respectively, while lower sample sizes were included in this study (n=17) and that of portus et al.[7] (n=14). with larger samples even fair correlations will show statistical significance (p<0.05). also, previous studies did not investigate a potential correlation between br speed and injury status separately, while in this study bowlers who remained injury free throughout the season bowled with a more flexed knee while still attaining higher br speeds, as indicated by the good to excellent inverse correlation (r=– 0.79; p=0.18). bowlers who remained injury free may have used strategies other than the front knee angle, like neuromusculoskeletal control such as balance and proprioception, to attain higher br speeds. both balance[14] and proprioception[17] have been associated with injury in previous research among pace bowlers. study limitations two limitations were evident in this study. the first is that the frame rate of the cameras used was lower than that used in recent studies, and a higher frame rate would have been ideal. the second limitation was that the data of 14 bowlers could not be included in n o n -i n ju re d b r a n g le (d eg re es ) non-injured average speed (km/h) 135110 115 120 125 130 0 180 160 140 120 100 80 60 40 20 fig. 5. relationship between br speed and knee angle in the non-injured at the start of the season (n=8) (r=–0.79; p=0.18). sajsm vol. 27 no. 3 2015 81 the analysis as a result of missing markers encountered during the 3d kinematic analysis, mainly due to the high-speed bowling action. conclusion body actions that result in higher br speeds (enhanced performance) have raised concerns among health professionals, since the increased strain on the body that results in greater performance may also increase injury likelihood. the focus on injury prevention in pace bowlers is vital, but it cannot be examined in isolation. in the investigation of variables related to injury, the need for optimal bowling performance should also be taken into account. in addition, knee angle should be interpreted as part of the kinetic chain and kinematics at the ankle, hip and lower back should be taken into account. injuryand bowling performance-related factors associated with the knee classification categories as developed for and used in this study should be further investigated among bowlers. further research needs to be conducted into non-technique-related strategies to attain higher br speeds among bowlers who remain injury free during a cricket season. the strategies used to attain higher br speeds may have contributed to the prevention of injuries. acknowledgements. we would like to acknowledge each participant for his time, effort and enthusiasm. funding for this project was received from the national research foundation, the carnegie foundation of new york and the local society of physiotherapy. these funding organisations played no role in the collection, analysis or interpretation of data and had no right to approve or disprove of the final manuscript. references 1. roca m, elliott b, alderson j, foster d. the relationship between shoulder alignment and elbow joint angle in cricket fast-medium bowlers. j sports sci 2006;24(11):11271135. [http://dx.doi.org/10.1080/02640410500497618] 2. ferdinands re, kersting u, marshall rn. three-dimensional lumbar segment kinetics of fast bowling in cricket. j biomech 2009;42(11):1616-1621. [http://dx.doi. org/10.1016/j.jbiomech.2009.04.035] 3. crewe h, campbell a, elliott b, alderson j. lumbo-pelvic loading during fast bowling in adolescent cricketers: the influence of bowling speed and technique. j sports sci 2013;31(10):1082-1090. [http://dx.doi.org/10.1080/02640414.2012.762601] 4. portus m, mason br, elliott bc, pfitzner mc, done rp. technique factors rel ate d to b a l l rele as e sp e e d and t r un k injur ies in hig h p er for mance cricket fast b ow lers. sp or ts biomech 2004;3(2):263-284. [http://dx.doi. org/10.1080/14763140408522845] 5. wormgoor s, harden l, mckinon w. anthropometric, biomechanical, and isokinetic strength predictors of ball release speed in high-performance c r i cke t f a st b ow l e rs . j sp or t s s c i 2 0 1 0 ; 2 8 ( 9 ) : 9 5 7 9 6 5 . [ http : / / d x . d oi. org/10.1080/02640411003774537] 6. bartlett rm, stockill np, elliott bc, burnett af. the biomechanics of fast bowling in men’s cricket: a review. j sports sci 1996;14(5):403-424. [http://dx.doi. org/10.1080/02640419608727727] 7. portus mr, sinclair pj, burke st, moore dj, farhart pj. cricket fast bowling performance and technique and the influence of selected physical factors during an 8-over spell. j sports sci 2000;18(12):999-1011. [http://dx.doi. org/10.1080/026404100446801] 8. zhang y, unka j, liu g. contributions of joint rotations to ball release speed during cricket bowling: a three-dimensional kinematic analysis. j sports sci 2011;29(12):1293-1300. [http://dx.doi.org/10.1080/02640414.2011.591417] 9. elliott bc, hardcastle ph, burnett ae, foster dh. the influence of fast bowling and physical factors on radiologic features in high performance young fast bowlers. sports med train rehabil 1992;3(2):113-130. 10. orchard j, james t, alcott e, carter s, farhart p. injuries in australian cricket at first class level 1995/1996 to 2000/2001. br j sports med 2002;36(4):270-274;discussion 5. 11. stretch r, raffan r. injury patterns of south african international cricket players over a two-season period. s afr j sports med 2011;23(2):45-49. 12. frost wl, chalmers dj. injury in elite new zealand cricketers 2002-2008: descriptive epidemiology. br j sports med 2014;48(12):1002-1007. [http://dx.doi.org/10.1136/ bjsports-2012-091337] 13. orchard j, newman d, stretch r, frost w, mansingh a, leipus a. methods for injury surveillance in international cricket. j sci med sport 2005;8(1):1-14. 14. olivier b, stewart av, olorunju sa, mckinon w. static and dynamic balance ability, lumbo-pelvic movement control and injury incidence in cricket pace bowlers. j sci med sport 2015;18(1):19-25. 15. portney lg, watkins mp. foundations of clinical research: applications to practice. london: pearson prentice hall, 2009. 16. putnam ca. sequential motions of body segments in striking and throwing skills: descriptions and explanations. j biomech 1993;26 suppl 1:125-135. 17. olivier b, stewart av, mckinon w. injury and lumbar reposition sense in cricket pace bowlers in neutral and pace bowling specific body positions. spine j 2014;14:14471453. [http://dx.doi.org/10.1016/j.spinee.2013.08.036] sajsm 487.indd original research 74 sajsm vol. 25 no. 3 2013 background. the chronological age of the ordinary ghanaian has often been difficult to verify as registration at birth is not compulsory. consequently, an accurate method of age determination is needed in competitive age-restricted sports. objective. to evaluate the age of ghanaian soccer players who are aspiring to play for the national under-17 (u17) team, using the degree of fusion of the distal radius on magentic resonance imaging (mri) and comparing it with the fédération internationale de football association (fifa) mri grading. methods. mri scans of the left wrists of 86 players aspiring to play for the national u17 football team were recruited for the study during a ‘justify your inclusion tournament’ organised by the ghana football association between june and august 2012. the study was conducted in a diagnostic centre in accra using a 0.35t mri scanner. the images were analysed using the previously published fifa grading system. results. the mean chronological age of the players was 15.4 years (standard deviation ±0.7; range 12 17). the study showed that 43.0% of the mri images were grade 6 (≥17 years) in relation to the degree of fusion of the distal radius, and 93.0% of the grade 6 players were aged 15 16 years chronologically. there was no significant correlation between the chronological age and the degree of fusion (r=0.075; p=0.493). conclusion. ghanaian u17 soccer players seem to be more biologically mature than a normative population of the same age category. the lack of correlation between age category and degree of fusion supports the suspicion that most ghanaian players may not know their true age. s afr j sm 2013;25(3):74-76. doi:10.7196/sajsm.487 mri to determine the chronological age of ghanaian footballers b d sarkodie,1 bsc, mb chb, fwacs; e k ofori,2 bsc (hons); mphil, phd; p pambo,3 bsc, msc, mb chb 1 radiology department, tamale teaching hospital, tamale, ghana 2 department of radiography, school of allied health sciences, college of health sciences, university of ghana, korle-bu-accra, ghana 3 ghana football association, ghana corresponding author: b d sarkodie (ghana_neo@yahoo.com) despite the increasing use of radiological investigations worldwide as a result of their known benefits to society,[1] diagnostic x-rays are by far the largest contributor to the collective dose of all man-made radiation.[2,3] exposure to such radiation is associated with an increased long-term risk for malignant disease.[4,5] the basic safety standards of the international atomic energy agency (iaea) for the protection against ionising radiation and safety of radiation sources[6] recommends considering alternative imaging methods (e.g. magnetic resonance imaging (mri) or ultrasound) if they provide equal or better information. these modalities avoid the use of ionising radiation and the subsequent risks to the patient.[7] accurate age determination is vital in any competitive agerestricted sport; inconsistencies in age lead to unequal chances and counter both the spirit of the game and ‘fair play’. the determination of skeletal maturity has an important place in the practice of paediatrics, especially in relation to endocrinological problems and growth disorders.[8] standard radiographs of the left wrist are widely used for assessment of skeletal age, although they may vary depending on ethnic origin.[9,10] the need for an alternative method of determining age and maturity has been raised by the iaea,[9] which does not allow an x-ray examination except when clinically justified for the individual. consequently, the use of x-rays (a source of radiation exposure) to determine whether or not players are over age, is not encouraged. whereas standard radiographs with the attendant radiation risk cannot be justified as the screening tool in soccer populations, age estimation on the basis of grading of fusion of the distal radius by mri has been shown to be a reliable and valid method in 14 19-year-old soccer players.[11] in ghana, chronological age has often been a difficult challenge, as registration at birth is not compulsory. this gives room for falsification of true age, which could lead to cheating.[10] it has been suggested that age, experience, body size and stage of puberty contribute considerably, in different combinations, to the variance of some football skills such as dribbling with a pass, ball control with the body and shooting accuracy.[12] also, players with a greater relative (or possibly false lower) age are more likely to be identified as ‘talented’ because of the likely physical advantages that they have over their ‘younger’ peers.[12] we aimed to evaluate the age of aspiring ghanaian under-17 (u17) footballers using the degree of fusion of the distal radius on mri and to compare it with fédération internationale de football association (fifa) mri grading. methods the study was prospective and cross-sectional, employing mri scans of the left wrist of 86 players aspiring to play for the national u17 football team. table 1 summarises the characteristics of the mri equipment used in the study. participants with a chronological age of 12 17 years were recruited during a ‘justify your inclusion tournament’ organised by the ghana football association between june and august 2012. the study was conducted in the sweden ghana medical centre (sgm) in accra. the degree of fusion of the left distal sajsm vol. 25 no. 3 2013 75 radial physis was determined by a team comprising two consultant radiologists. the images and their corresponding reports were analysed concurrently using the previously published fifa grading system.[9,11] statistical analysis inter-rater agreement was calculated using kappa.[13,14] kappa values can range from 0 (no agreement) to 1 (total agreement). to measure the inter-rater agreement, a random selection of 20 of the images which had been assessed by the first consultant radiologist were graded blindly by the second consultant radiologist and vice versa. the results were then compared and kappa was calculated using spss (version 17) to determine the level of inter-rater agreement. both descriptive and inferential statistics were carried out using spss. results age and degree of fusion a total of 86 players with self-reported ages of 12 17 years presented for the mri scan of the left wrist. the mean age of the players was 15.4 years (sd ±0.7). the majority of the players (80/86; 93%) were aged between 15 and 16 years. table 2 shows the crosstabulation of self-reported chronological age and the degree of fusion. table 3 summarises the distribution of players according to each grade of fusion. inferential analysis the self-reported chronological ages according to the six grades of distal radius fusion are presented by the error bar plots in fig. 1. mean ages and 95% cis were calculated using spss (version 17). a scatter plot of self-reported chronological age v. degree of fusion is presented in fig. 2. inter-rater agreement kappa was calculated to determine the level of agreement between the two radiologists. a kappa value of 0.94 (94.0%) was recorded, indicating very good agreement. however, there was no significant correlation between the chronological age and the degree of fusion (r=0.075; p=0.493). discussion in fifa u17 competitions, players must have been born on 1 january and/or be <17 years old before the year of the tournament, i.e. the players in fifa u17 can be aged 17 years at the start of the championship. because of biological variability, the ‘true’ age of an individual can only be estimated with a certain probability, but mri of the wrist has shown to be a valid and a reliable method for estimating age in 14 19-year-old soccer players in a normative population.[9] fifa requires all players to undergo a mandatory mri test before the regional and u17 world cup tournament. based on the findings of previous studies, [9,10] the probability of complete fusion occurring prior to 17 years of age is <1%. in other words, if mri shows complete fusion of a player’s wrist, the player is likely to be older than 17 years with a certainty of >99%. however, this study did not include any black africans. table 1. characteristics of the mri equipment used in the study parameter description scanner make magnet type magnetic field strength type of coil protocols for left wrist (bone age determination) frequency phase number nsa thickness interval field of view siemens permanent 0.35 t wrist coronal 256 hz 224 4 3 mm 2.5 mm 180 mm 16.5 15.5 14.5 16.0 15.0 14.0 grade 1 grade 2 grade 3 grade 4 grade 5 grade 6 fifa grade of distal radius fusion c h ro n o lo g ic al a g e o f p la ye r (y ea rs ), 95 % c i fig. 1. error bar plot with 95% ci for chronological age by degree of fusion. 1 2 3 4 5 6 17 16 15 14 13 12 degree of fusion se lf -r ep o rt ed c h ro n o lo g ic al a g e (y ea rs ) fig. 2. scatter plot of self-reported chronological age v. degree of fusion. 76 sajsm vol. 25 no. 3 2013 in the present study, the mri images of 43.0% (n=37) of the aspiring players were graded 6, i.e. completely fused or over-age, which is substantially higher compared with the findings of other studies in europe and asia.[9,10] the highest number of players with complete fusion (grade 6) was found among those with a chronological age of 16 years. approximately three-quarters (75%) of the players aged 15 and 16 years were over-age (grade 6). from the mri results, the aspiring players seemed to be more mature than a normative population of soccer players. no significant correlation was observed between age category and grade of fusion (r=0.075; p=0.493). this finding is consistent with previous studies (p=0.13).[9,10] the missing correlation between the age presented by participants and biological maturity assessed from fusion of the distal radius cannot be explained definitively. this discrepancy may support the suspicion that some u17 players are older than stated in their official documents; however, ethnic variations may also account for the difference between chronological age and the degree of fusion on mri. it is reported that prepubertal american children of european descent have significantly delayed skeletal maturation compared with those of african descent, and postpubertal american children of european descent have significantly advanced skeletal maturation compared with postpubertal children of african descent.[15] conclusion the use of mri to investigate the degree of fusion of the left distal radius has given an indication of the maturity of aspiring u17 soccer players in ghana. on the basis of the findings, the self-reported ages of these players might not have been correct compared with results from normative studies, although other factors may be responsible for the differences. accurate age determination of participants is important in competitive sport. however, predicting age using the degree of fusion of the left distal radius of the wrist as a method to verify chronological age may lack the accuracy needed and may result in many false-positive or false-negative results, until a normative study is carried out on black africans. registration at birth is not compulsory in many african countries such as ghana; therefore, it has been argued that a normative study may be difficult to carry out. however, there are various ways to verify the ages of 14 19-year-olds, especially in a situation where there is no incentive for one to hide their true age. there is an urgent need for a comprehensive study involving black africans to ensure that the black african footballer is given a fair playing ground by the fifa. acknowledgements. we acknowledge the support and co-operation of the staff of the sweden ghana medical centre (sgm) in accra, ghana. references 1. saunders m, budden a, maclver f. dose implications of fluoroscopy-guided positioning (fgp) for lumbar spine examinations prior to acquiring plain film radiographs. br j radiol 2005;78:130-134. [http://dx.doi.org/10.1259/bjr/50195548] 2. unscear. report to the general assembly, with scientific annexes. new york: united nations, 2000. 3. manning d. the risk of cancer from radiography. j radiography 2004;10(3):171-172. [http://dx.doi.org/10.1016/j.rad.2004.02.014] 4. berrington de gonzalez a, darby s. risk of cancer from diagnostic x-rays: estimates for the uk and 14 other countries. lancet 2004;363(9406):345-351. [http://dx.doi. org/10.1016/s0140-6736(04)15433-0] 5. engel-hills p. radiation protection in medical imaging. j radiography 2006;12(2):153160. 6. international atomic energy agency (iaea). radiological protection for medical exposure to ionizing radiation. iaea safe standard series 2002. safety guide no. rsg-1.5. vienna: iaea, 2002.  7. valentine j. avoidance of radiation injuries from medical interventional procedures. ann icrp 2000;30(2):7-67. 8. tanner jm, whitehouse rh, marshall wa, et al. prediction of adult height from height, bone age, and occurrence of menarche, at ages 4 to 16 with allowance for mid parent height. arch dis child 1976;50(1):14-26. 9. dvorak j, george j, junge a, hodler j. application of mri of the wrist for age determination in international u-17 soccer competition. br j sports med 2007;41(8):497500. [http://dx.doi.org/10.1136/bjsm.2006.033431] 10. braude sc, henning lm, lambert mi. accuracy of bone assessments for verifying age in adolescents – application in sport. south african journal of radiology 2007;11(2):4. 11. dvorak j, george j, junge a, hodler j. age determination by magnetic resonance imaging of the wrist in adolescent male football players. br j sports med 2007;41(1):4552. [http://dx.doi.org/10.1136/bjsm.2006.031021] 12. malina rm, eisenmann jc, cumming sp, et al. maturity-associated variation in the growth and functional capacities of youth football (soccer) players 13 15 years. eur j appl phsyiol 2004;91(5):555-562. [http://dx.doi.org/10.1007/s00421-003-0995-z] 13. meltzoff j. criteria and criteria measure, critical thinking about research. washington dc: american psychological association, 1998. 14. bryman a. social research methods. 3rd ed. oxford: oxford university press, 2008:265. 15. mora s, boechat mi, pietka e, huang hk, gilsanz v. skeletal age determinations in children of european and african descent: applicability of the greulich and pyle standards. pediatric res 2001;50(5):624-628. table 2. cross-tabulation of self-reported chronological age and degree of fusion degree of fusion self-reported chronological age (years) total12 14 15 16 17 grade 1 0 1 4 0 0 5 grade 2 0 0 2 3 0 5 grade 3 0 0 2 3 0 5 grade 4 0 0 4 6 0 10 grade 5 1 0 11 11 1 24 grade 6 0 3 15 19 0 37 total 1 4 38 42 1 86 table 3. distribution of players in each grade of fusion degree of fusion n (%) self-reported chronological age (years), mean (±sd) grade 1 5 (5.8) 14.8 (±0.5) grade 2 5 (5.8) 15.6 (±0.6) grade 3 5 (5.8) 15.6 (±0.6) grade 4 10 (11.6) 15.6 (±0.5) grade 5 24 (27.9) 15.4 (±0.9) grade 6 37 (43.0) 15.4 (±0.7) total 86 (100) 15.4 (±0.7) 74 sajsm vol. 24 no. 3 2012 state of sport in south africa: questions that need answers editorial the application of science governing human performance in the laboratory is well refined with a defined set of guiding principles. for example, rules are in place about recruiting subjects, randomising them into different groups, familiarising them with the equipment used to measure performance, and then testing them before and after the implementation of the treatment. the implementation b eing e valuated may have something to do with nutrition, specialised training, tapering or pacing. differences in the performance measurements conducted before and after the intervention are analysed using statistics, and conclusions can be made about whether or not there are differences as a result of the implementation of the treatment. the magnitude of the effect can be calculated and viable conclusions can be reached. although the conclusions are open to interpretation, the findings are generally clear for all to see. this scenario describes the assessment of performance in the laboratory; how do we translate this set of principles and logic into evaluating the performances of our elite sportsmen and -women competing on the international platform? how can we determine the ‘health’ of a particular sporting code? one possible way of quantifying performance is to consider medals won at the olympics. after the london olympics, much was made of south africa’s 23rd place and the 6 medals (3 gold, 2 silver and 1 bronze) of the south african athletes. this performance was much better than in beijing (2008) (1 silver) and marginally better than athens (2004) (1 gold, 3 silver and 2 bronze). however, it may be argued that the performance was on a par with the performance in atlanta (1996) (3 gold, 1 silver and 1 bronze), achieved only two years into our new democracy. these criteria of evaluating overall performance are not absolute and the answer will vary depending on the agenda of the person doing the evaluation. furthermore, when using only medals as a gauge of success, the athletes that achieved personal best performances, but only came 4th in their event, are excluded from the count. likewise those athletes that make the final, meaning they are in the approximate top 10 in the world, do not contribute to this simple medal count exercise. this type of assessment is also dependent on the state of the competitors from other countries – something that can clearly vary, as shown by australia (10th place in 2012 with 35 medals dropping from 6th place and 46 medals in 2008). a much more robust way of assessing performance and the ‘health’ of a particular sporting code is to examine the sport at a more holistic level. such a method will provide more meaningful results that can be monitored over time to determine any trends. the information can also be useful for assessing the efficacy of implementation, and whether money allocated to the sport is being spent in the most efficient way. such a method is much more complicated than merely counting medals. for example, the following questions need answers before a firm conclusion about the state of the sport can be made. • how many participants are there in the sport in the country? • what are the demographics of the participants? • what is the state of the facilities and equipment associated with that sport? • what competitive leagues exist? • do these leagues have age-group competitions? • is there much attrition from the youth leagues to the adult leagues? • how many coaches are fully engaged in the sport? • do these coaches have any formal training? • how are talented athletes identified? • does the sporting code have a programme in place to nurture talent, and develop it fully through to adult levels? • are policies in place for those athletes who may get injured while participating in the sport? • is the federation administered professionally and are succession plans in place for the administrators of the sport? • how many participants are ranked in the top 10 in the world? in the top 50? in the top 100? answers to these questions are not easily obtained. however, monitoring systems need to be implemented so that an ongoing assessment of the sport can be made and the answers to these questions provided. once that status is achieved will we be able to comment accurately on the status of sport in the country and whether we are improving or not. this edition of the journal has two original research studies. the first paper examines the short-term effect of kinesio tape on the explosive power of the gluteus maximus of male athletes. this is an example of a good laboratory study, with findings that can be translated into practical applications. the second study examines the playing time of professional rugby players from 2007 to 2011. the design of this study is aligned to the concept of monitoring the state of the game so that it can be managed more effectively. lastly, the abstracts from the first international conference of by the biokinetics association of south africa to be held in potchefstroom from 27 to 29 september 2012 are also presented in this edition. the broad scope of the content of the abstracts shows the important role that the profession of biokinetics is fulfilling. the authors of these studies are challenged to convert these abstracts into publications so that the information can be shared with a broader audience. mike lambert editor-in chief s afr j sm 2012;24(3):74. doi:10.7196/sajsm.345 sajsm vol 24 no. 1 2012 15 original research introduction trail running events are becoming increasingly popular with amateur athletes.1 these are generally regarded as more strenuous than road running due to the nature of the trails, which can involve diverse challenges including single track paths on steep ascends and descends in mountains, crossing rivers and running along grasslands and through forests.2 although physiological response to single-day trail running has been assessed,1-4 the cumulative effects of multi-day trail running on markers of muscle damage and inflammation have not yet been reported. prolonged endurance exercise causes muscle damage that initiates an inflammatory response and subsequent remodelling of muscle.5 the extent of this damage is augmented by increases in exercise intensity, the eccentric component of contraction,6-8 heat stress index and dehydration.3 the greater contractile load per unit in muscles of the lower limb, as they contract eccentrically during downhill running,8 has been associated with increased mechanical damage to the muscle fibres, resulting in muscle membrane leakage and elevated concentrations of circulating muscle enzymes and proteins.9 systemic markers of inflammation also rise5,7 and swelling, decreased mobility and delayed-onset muscle soreness (doms) are common.5,6 the presence of myoglobin in the urine has been reported in severe cases.5 although the direct cause-and-effect relationship between dehydration and hyperthermia is currently contentious,10 it has been reported that these augment exercise-induced muscle damage,3,4 detrimentally affect performance and pacing during trail running and increase post-exercise doms.3,4,11 cleary et al.11 reported an association between dehydration and hyperthermia and attributed an increase in muscle damage to the increased degradation of muscle proteins with elevated deep-muscle temperature. the aims of the study were therefore to determine effects of a multiday trail run on the markers of muscle damage and inflammation in experienced recreational runners, measuring serum and urinary levels of selected skeletal muscle, cardiac and hepatic proteins in association with changes in red and white blood cell and serum cortisol concentrations before and after every stage and at 24 hours post-race (24pr) and 72 hours postrace (72pr). a further aim was to assess the possible effect of dehydration and hyperthermia on the markers of muscle damage and inflammation. it was hypothesised that the three consecutive days of trail running would result in elevations of systemic and urinary markers of skeletal muscle damage and inflammation that are higher than previously reported during road running events of similar duration, and that the muscle damage and inflammation would be augmented by hyperthermia and dehydration. method ethical clearance this 8-day observational cohort study took place during a 3-day trail run and for 5 days following completion of the three cranes trail run, at karkloof, kwazulu-natal, south africa on 25 27 february 2011.  following approval by the biomedical research ethics committee of the university of kwazulu-natal, subjects gave written consent after having been informed of the experimental procedures.    subjects twenty-one apparently healthy subjects, who met the inclusion criteria (age: ≤50 and an average training distance of 60 km per week) abstract objectives. to investigate the effect of a 3-day trail run on markers of muscle damage and inflammation in recreational runners. main outcome measures. pre-and post-stage and 24-hour and 72hour post-race concentrations of serum creatine phosphokinase (cpk), high sensitivity c-reactive protein (hscrp), cortisol, cardiac troponin t (ctnt), and osmolality (sosm) as well as urinary myoglobin (umb), changes in body mass, delayed onset muscle soreness (doms) and thigh circumference (tc) were measured. continuous recordings of heart rate (hr) and intestinal temperature (tintest ) were made throughout each stage. results. heart rate ranged between 77% and 83% age-predicted maximum (apmax) and tintest between 36.1 and 40.2ºc during the three stages. significant rises in mean serum cpk, hscrp, sosm and blood neutrophil count reached peak concentrations of 1488u/l, 8.91mg/l, 298mosm/l and 10.21 109/l (p<0.001), respectively. no evidence of elevations in umb and ctnt were detected. the stage-induced increments in doms correlated positively with cpk, r=0.71; 95% ci [0.62, 0.78], tc decreased significantly post s1post and s2post (p<0.05) and a maximum mean body mass loss of 3.09% (±1.04%) occurred during s2. conclusion. three consecutive days of 95-km trail running resulted in low markers of muscle damage and inflammation, despite the maintenance of a heart rate above 77% apmax, tintest rising above 39oc and mean body mass decrement of >2.0%. low markers of muscle damage and inflammation following a 3-day trail run emmerentia c denissen (mtech hom) anton h de waard (mtechhom) navin r singh (msc (eng)) edith m peters (phd) division of human physiology, school of laboratory medicine and medical sciences, college of health sciences, university of kwazulunatal, westville, durban, south africa correspondence to: edith peters-futre (futree@ukzn.ac.za) 16 sajsm vol 24 no. 1 2012 and did not use chemical stimulants, were accepted into the study. nineteen (6 males, 13 females) completed all three stages of the race and 15 runners (4 males, 11 females) completed all withinand postrace assessments. setting the three cranes trail run, over 3 days and a total distance of 95 km, was divided into 3 consecutive stages comprising 29.3, 37.9 and 27.8 km, starting and finishing each day at the same base camp.  athletes were accommodated in a race village and full catering was provided for the duration of the race, including at the aid stations along the route. the routes consisted of gravel and forestry roads, narrow rocky mountain footpaths and grassy jeep track. elevation gains reached 1 020, 1 226 and 680 m, while elevation losses were recorded at 1 021, 1 231 and 687 m during s1 (stage 1), s2 (stage 2) and s3 (stage 3) respectively (table 1). selected images of the running terrain are presented in fig. 1. baseline measurements following race registration the afternoon before the race, basic anthropometric measurements were recorded, including body mass (kg), stature (cm) in bathing suits without shoes, thigh circumference (tc) (measured 15 cm above the superior border of the patella) and four-site skinfold (supra-iliac, subscapular, biceps  and triceps) for the fig. 1. selected images of the running terrain. sajsm vol 24 no. 1 2012 17 determination of % body fat.12 a pre-race questionnaire detailing the athletes’ running and racing experience, training terrain and health status was also completed. daily protocol pre stage the subjects presented themselves to a designated testing area 30 90 minutes before the start of the stage, handing in a first earlymorning urine sample. tc was measured, venous blood sampling was conducted in the seated position and resting heart rate (hr) and blood pressure (bp) were recorded after a 3 5-minute period of relaxation. a simple pre-stage questionnaire including a rating of the degree of muscle soreness they were experiencing, was completed and the subjects were asked to keep a record of their fluid intake and urine output during the stage. after breakfast and final voiding of bladders, body mass (measured in running attire without shoes), was taken within 5 minutes prior to the start of the event. within stage environmental conditions and temperature were supplied on the hour by a meteorological station located 9.5 km from the base camp.  heart rate was recorded using a polar hr monitor (polar electro oy, finland) at 5-minute intervals and % age-predicted maximum (apmax) was determined according to the formula, 220-age.14 a subsample of 12 athletes volunteered to ingest the cor-temp disposable tablets, containing temperature sensors (hq inc, palmetto, fl), at least 3 hours prior to the start of each stage. the hr and intestinal temperature (tintest) data are part of a more detailed study focussing on the relationship between tintest, hr and hydration status. 13 post stage the subjects proceeded directly to the designated testing area where bp, mass and tc were measured within 3 5 minutes, blood and urine samples were taken and a short doms and post-stage questionnaire providing details regarding the use of non-steroidal anti-inflammatory drugs (nsaids) and muscle soreness, were completed. in available athletes (n=10), a further measurement of tc was taken 4 hours after completion of s1 and s2. the same protocol was followed preand post-stage on the 3 days of the race.  post race at 24pr and 72pr, participants presented for further blood/urine sampling, bp, hr and anthropometric measurements. they were also requested to complete a doms questionnaire for the 5 days following the race, using a five-point likert scale, and to return this together with a general post-race questionnaire, following completion of the study. haematological analysis and anthropometric measurements each measurement was carried out by the same researcher for all subjects and at each time point. venous blood samples were drawn from the antecubital fossa, with subjects in the seated position, within 5 15 minutes of completing the stage.  blood samples for the assessment of full blood count (fbc) and serum osmolality (sosm) and urine samples were stored at 4ºc and transported to a commercial pathology laboratory. complete blood counts were measured on an advia-120 hematology analyzer (siemens healthcare diagnostics, deerfield, il) and included erythrocyte indices and differential leukocyte counts. both urine and serum osmolality were measured by freezing-point depression, using a kyoto daiichi osmostat, om 6020 (japan).  urine samples were also assessed for myoglobin (umb) and specific gravity using the refractive index method on a beyer test strip.  further aliquots of serum, separated by centrifugation @ 3 000 rpm and stored in dr y ice were transferred to an -80ºc ultrafreezer or transported to a commercial pathology laboratory for analysis of creatine phosphokinase (cpk), cortisol, cardiac trop onin t (ctnt) and high sensitivity c-reactive protein (hscrp) concentrations.  statistical analyses data are presented as mean ± standard deviation (sd). the significance of the accumulative time-dependent stage-induced changes from pre-race (s1pre) to post race (s1post, s2post, s3post), as well as recovery rates were assessed comparing s2pre, s3pre, 24pr and 72pr to baseline (s1pre,), s2pre and s3pre were assessed for the entire group using repeated measures one way analysis of variance. the time point of the significant differences was confirmed using a tukey post hoc analysis. comparisons between nsaid users and non-users were conducted using independent student’s t-tests. pearson’s product moment coefficient of correlation, with a confidence interval (ci) of 95%, was used to test the relationship between the changes in measured outcomes including cpk, neutrophil concentrations, hscrp and serum cortisol.   all statistical calculations were performed using spss, version 18 (spss inc., chicago, usa). level of significance was set at p<0.05.  results environmental conditions temperature recorded on the hour during the three stages of the race ranged from 11.5ºc to 22.8ºc (table 1). it did not rain, maximum wind speed recorded was 2.8 m/s and the relative humidity ranged from 54% to 97%. table 2. mean ± sd baseline physical characteristics of subjects (n=19) variable mean±sd age (years) 39.3±7 height (cm) 169.0±10 mass (kg) 65.8±12 % body fat 21.7±4 resting heart rate (bpm) 56.9±5 systolic blood pressure (mmhg) 124.7±7 diastolic blood pressure(mmhg) 81.8±7 table 1. elevation changes (m) and ambient temperature ranges during the three stages of the trail run elevation gain  elevation loss ambient temp erature range (ºc) day 1 1 020 1 021 11.5 21.7 day 2 1 226 1 231 12.4 22.8 day 3 680 678 12.1 21.2 total 2 926 2 930 18 sajsm vol 24 no. 1 2012 subjects as is shown in tables 2 and 3, athletes ranged from 25 to 50 years of age, their weekly training distance averaged 65.9±20.1km per week for 12.4 years (range 2 27 years) and they presented without abnormalities in their vital signs. of the 19 subjects, 12 used nsaids, including aspirin, ibuprofen and diclofenac. of the 21 subjects who initially agreed to participate in the study, one subject (male) withdrew after s1 due to an ankle injury and another (female) after s2 due to medical reasons. the baseline physical characteristics of the remaining 19 subjects are provided in table 2. four subjects were however unable to provide blood samples at 24pr and 72pr. intensity of effort the mean ±sd and range of time spent completing each stage and average hr on the run, are given in table 3. total average running time of the athletes was 12h57±2h51. markers of muscle damage and inflammation as shown in table 4, these included a significant increase in circulating neutrophil concentrations (p<0.001) which peaked at 10.21±1.54 109/l at s1post, serum cpk and hscrp which peaked at s3post at 1 488± 1 053u/l (p≤0.001) and 8.91±6.63mg/l (p≤0.001), respectively. ctnt and umb were undetected in all samples throughout the 3-day event. an exercise-induced increase in serum cortisol concentration was only detected following s2post. tc decreased significantly from 54.1±4.4 cm at s1pre to 51.8±3.9cm at s1post (p<0.001) and returned to the pre-race measurement of 54.1±4.0 cm at 24pr. doms ranged from 4.8±1.6, 5.6±1.8 and 5.1±1.1 at s1post, s2post and s3post, respectively, and decreased to 1.73±1.3 at 24pr. significant positive correlations were evident between blood neutrophil concentrations and serum cpk, r=0.27, 95% ci [0.11, 0.41], serum cpk and hscrp concentrations, r=0.50, 95% ci [0.29, 0.66] and doms and cpk, r=0.71, 95% ci [0.62, 0.78]. dehydration, intestinal temperature (tintest), hr and muscle damage the mean % body mass loss for the entire group (n=19) during the three stages was 2.9±0.7, 3.1±0.8 and 1.9±0.9, while the mean sosm (n=19) increased from 288.9±4.8 to 293.7±5.7 (p=0.003), 288.4±6.4 to 295.6±6.0 (p=0.003) and 292.2±4.1.to 295.0±5.6 (p=0.006) mosm/ kg, during s1, s2 and s3, respectively. when the pooled data for each stage were compared (n=51), the paired post-pre changes in sosm correlated inversely with the changes in % body mass, r=-0.36, 95% ci [-0.57,-0.094]. the pooled data examining the relationship between the change of sosm and change in serum cpk for the three stages (n=57) revealed an insignificant positive correlation (r=0.034, 95% ci [-0.228, 0.291]. the maximum tintest ranged between 38.3ºc and 40.2ºc and only exceeded 40º c in two of the 12 athletes monitored (table 5). the relationship between change in tintest and serum cpk was insignificant (p>0.05) for the 11 individuals from whom complete sets of data were available (r=0.24, 95% ci [-0.42, 0.734]). users of nsaids the 12 athletes who used nsaids had maximum serum cpk and hscrp concentrations of 1 332±943.5 u/l and 8.58±6.7 mg/l at s3post and the non-users 1 754±1 251.3 u/l and 9.47±7.0 mg/l, with no significant difference between the groups (p=0.456; 0.788). the neutrophil count reached a maximum of 9.95±2.1 and 9.75±0.4 109/l, respectively, for users and non-users (p=0.82). there was also no significant difference between nsaid users and non-users in terms of serum cortisol, post race doms scores, running times, tc or sosm (p>0.05). discussion evidence of muscle damage and inflammation the results of the present study indicate that very little muscle damage and inflammation occurred during 3 days of trail running despite athletes running for a total average of 12h57 at an average hr of 77 83% apmax (table 3). the serum cpk concentration, which increased progressively to reach peak concentrations at s3post, indicated only a mild cumulative effect of muscle damage during the race, which rejects the original hypothesis. furthermore, the changes in neutrophil count, serum cortisol and hscrp concentrations and doms also confirm low levels of inflammation and a rapid recovery. most athletes in our study had no muscle soreness at 72pr, which correlated with the cpk concentration that had dropped close to the clinical upper limit of normal by 72pr.15 the consistently low release of muscle proteins into the bloodstream in all 19 subjects, which was also not accompanied table 3. training status and performance characteristics of athletes (n=19) characteristics mean±sd range running experience number of years number of competitive endurance events 12.4±8.1 136.3±55.6 2 27 18 500 weekly training distance (kilometres per week) 65.9±20.1 12.5 105 number of days per week on different training terrains hills off road incl. forest /trail/beach road 1.4±0.8 1.7±1.5 3.9±1.3 1 4 0 6 0 5 race time (hour:minute:second) stage 1 stage 2 stage 3 4:04:31±25:54 5:39:12±25:31 3:14:15±21:06 3:06:06 5:22:48 4:14:56 7:46:27 2:38:38 6:51:50 average heart rate (beats per minute) stage 1 stage 2 stage 3 150.8±21.3 140.7±22.5 138.5±23.3 73 191 60 186 75 198 mean as %apmax* stage 1 stage 2 stage 3 83±8.8 78±7.8 77±8.1 71 112 55 105 63 105 data presented as mean (±sd) and range. *age-predicted maximum (220-age). sajsm vol 24 no. 1 2012 19 by elevation in ctnt and umb in this study, confirms a profile of low degrees of muscle damage. further evidence is the fact that tc was not significantly elevated at any post-stage or post-race time-point, but was reduced after s1 (p<0.001), confirming previous findings of reduced swelling and a post-race decrease in muscle mass.16 the low systemic markers of muscle damage and inflammation, when compared with previous findings following the comrades marathon16 confirm the findings of millet et al.1 who, in their study on the neuromuscular consequences of extreme running in a 166 km mountain ultra-marathon, reported that post-race serum concentrations of cpk, hscrp and neutrophils were lower than those measured after a road race with similar finishing times.1 these researchers attributed their findings of low concentrations of systemic markers of muscle damage and inflammation to the relatively soft underfoot surfaces and to the athletes frequently being forced to walk, jump and climb due to the technical demands of the terrain. during extensive exercise-induced muscle damage myoglobin may be released into the urine and be indicative of exertional rhabdomyolysis and possible risk of renal failure.8 clarkson9 however reported that exertional muscle damage in healthy athletes can cause profound serum cpk elevations without renal impairment. in our study the absence of umb was confirmed by the relatively low increases in systemic neutrophil, serum cpk and hscrp concentrations. in this study we suspect that although the primary factor which reduced the amount of repetitive and eccentric unidirectional stress encountered during the race was most probably the underfoot surfaces, the majority of which were primarily soft, large fluctuations in the pace of running and varied muscle recruitment patterns over the different terrains may also have played a role. the positive correlation between doms scores and cpk concentrations supports the findings of nieman et al.2 who, in their study on 60 participants in the 160 km 1-day western states endurance trail run in the sierra nevada mountains in northern table 4. mean±sd white and red blood cell indices and markers of muscle damage and inflammatory response before and after every stage and at 24pr and 72pr variable stage 1 stage 2 stage 3 24pr 72prpre post pre post pre post red blood cells (10 12 /l) 4.7 ±0.5 4.7 ±0.5 4.5 ±0.4 4.6 ±0.5 4.4 ±0.4 4.4 ±0.4 4.1 ±0.4 4.3 ±0.4 haemoglobin (g/dl) 14.4 ±1.3 14.3 ±1.2 13.7 ±1.0 14.1 ±1.2 13.2 ±0.9 13.3 ±1.1 12.7 ±0.9 13.2 ±1.2 haematocrit (%) 42.4 ±3.9 42.1 ±3.3 40.2 ±2.9 41.1 ±3.2 39.9 ±2.7 39.5 ±2.9 38.1 ±2.5 40.5 ±3.4 white blood cells (10 9 /l) 6.0 1.2 12.8* ±1.7 6.5 ±1.3 12.6** ±2.0 7.1 ±1.3 9.7*** ±2.2 6.7 ±1.2 6.5 ±1.5 neutrophils (10 9 /l) 2.9 ±0.7 10.2* ±1.5 3.4 ±1.0 9.7** ±1.9 3.7 ±1.0 7.3*** ±2.1 3.6 ±1.0 4.2 ±1.4 lymphocytes (10 9 /l) 2.1 ±0.5 1.4 ±0.5 2.2 ±0.6 1.73 ±0.6 2.4 ±0.7 1.5 ±0.4 2.1 ±0.6 1.6 ±0.5 eosinophils (10 9 /l) 0.3 ±0.2 0.1 ±0.1 0.2 ±0.2 0.1 ±0.1 0.3 ±0.2 0.1 ±0.1 0.2 ±0.2 0.1 ±0.1 basophils (10 9 /l) 0.04 ±0.02 0.1 ±0.03 0.0 ±0.02 0.06 ±0.05 0.05 ±0.02 0.0 ±0.02 0.04 ±0.02 0.03 ±0.01 cpk (u/l) 116.5 ±54.6 275.4* ±105.9 419.8 ±212.6 971.6** ±534.2 953.7 ±579.3 1488*** ±1053 595.6* ±361.4 201.9* ±111.3 hscrp (mg/l) 0.7 ±0.5 8.9* ±6.6 6.6* ±6.2 2.0* ±1.7 cortisol (nmol/l) 759.1 ±154.8 779.1 ±233.3 729.2 ±134.1 934.9** ±216.9 646.8 ±112.4 583.2 ±213.2 umb (mcg/ml) n/d n/d n/d n/d n/d n/d n/d n/d ctnt (µg/l) <0.01 <0.01 <0.01 thigh circum (cm) 54.1 ±4.4 51.8* ±3.9 54.1 ±4.6 53.3 ±4.6 53.4 ±4.4 53.8 ±4.2 54.1 ±3.9 53.5 ±3.8 *v. s1pre, p<0.001 **v. s2 pre, p<0.001 ***v. s3 pre, p<0.001 umb=urinary myoglobin; ctnt=cardiac troponin t; n/d=not detected. 20 sajsm vol 24 no. 1 2012 california, showed that there were significant associations between cpk, muscle soreness and the cytokines, interleukin (il)-6, il-10, il-1ra (receptor antagonist), granulocyte colony-stimulating factor and macrophage inflammatory protein 1β. systemic markers of cardiac damage the effect of prolonged strenuous exercise on systemic cardiac markers of damage has been studied extensively,18-20 with evidence of transient elevations during and immediately after exercise, which return to normal within 3 days in healthy athletes.18,19 these temporary elevations have been hypothesised to be due to myocardial stress and reversible cardiomyocyte membrane damage.18,19 exercise is known to cause an increased myocardial oxygen demand and cardiac troponin turnover in all athletes,18 which might be linked to tachyarrhythmias and sudden cardiac death, when associated with prolonged increases (>3 days) in ctnt concentrations above 0.05µg/l.18 at no stage during our study were increased ctnt concentrations measured, supporting the attenuated increase in serum cpk concentration and absent umb values as well as the lower concentration of serum cortisol despite maintenance of an intensity of effort which fluctuated from 63 to 112% apmax. it is possible that serum ctnt also did not increase due to the variation in hr (60 220bpm) that occurred during this race, which may have stimulated the cardiac muscle at irregular intervals and possibly reduced myocardial stress by permitting periods of recovery. users of nsaids both nsaid users and non-users were included in this study following recent findings that although markers of muscle inflammation are changed by nsaid usage, degree of muscle damage is unaffected.21,22 nieman et al.2 reported that nsaid users did not have reduced race times, muscle damage or doms, while friden and lieber6 reported that administration of nsaids after eccentric exercise resulted in a short-term benefit of pain relief, but a long-term detrimental effect on muscle adaptation, inhibiting protein synthesis by suppressing the inflammatory reaction. paulsen et al.22 also indicated that although nsaids inhibited prostaglandin synthesis and local and systemic responses, they did not affect actual markers of muscle damage. in this study there was however no statistical difference in the measured markers of muscle damage or inflammatory response between nsaid users and non-users. dehydration, intestinal temperature (tintest), hr and evidence of muscle damage although some athletes in our study experienced up to 4% body mass loss and others, on occasion, raced at a hr of more than 100% apmax (table 5), these athletes did not present with clinical signs of dehydration, severe hyperthermia or increased muscle damage as reflected by changes in sosm, tintest >40ºc or changes in serum cpk concentration, respectively. as the statistically significant (p<0.05) inverse correlation between % change in body mass and post-pre change in sosm was low (r=-0.365), sosm, widely reported golden marker of hydration status,23 was used to quantitate changes in hydration status. the correlation between hydration status and systemic markers of muscle damage, as reflected by stage-induced changes in sosm and serum cpk concentrations, although statistically significant, was low. hence it cannot be concluded from the 51 sets of paired data reported in this study that hydration status has an overriding effect on systemic markers of muscle damage. in the 12 individuals in whom continuous recordings of tintest were recorded (table 5), the correlation between race-induced changes in tintest and systemic markers of muscle damage was also low and statistically insignificant. the data provided in this study, although table 5. individual tintest , and associated hr, changes in hydration status and peak serum cpk concentration (n=12) subject number max tintest min tintest mean tintest max hr (bpm) mean hr max% apmax hr* mean% apmax hr * ∆sosm (mosm/kg) ∆body mass % max serum cpk ( u/l) 1 39.2 36.6 38.5 176 167 100 95 -3 -3.4 # 2 38.7 37.2 38.3 161 148 94 87 -6 -2.9 772 3 39.4 37.3 38.7 164 153 88 82 13 -2.7 1562 4 39.6 36.8 38.7 193 144 112 83 -6 -4.1 1057 5 39.2 35.2 37.4 168 154 95 87 10 -2.8 1523 6 39.8 36.1 37.7 168 160 92 87 7 -3.1 4478 7 38.7 36.9 38.2 152 140 89 82 11 -3.0 772 8 39.2 37.3 38.1 180 159 95 72 -23 -2.3 1198 9 40.2 37.1 38.0 181 144 102 81 -5 -3.3 1076 10 38.9 37.4 38.4 156 150 84 81 5 -3.2 1089 11 38.3 35.8 37.4 146 135 84 78 6 -2.8 1057 12 40.1 37.3 38.5 171 149 90 79 7 -2.3 1151 mean 39.3 36.8 38.2 168 150.3 93.8 82.8 4.17 2.99 1430 sd 0.6 0.7 0.4 13.4 9.0 8.0 5.8 9.42 0.49 1042 tintest=intestinal temperature; max=maximum; min=minimum; hr=heart rate; bpm=beats per minute; sd=standard deviation; cpk=creatine phosphokinase.* age-predicted maximum heart rate 14 # subject withdrew after completing s1. sajsm vol 24 no. 1 2012 21 based on a relatively small sample size, do not provide any support for the suggestion that rises in core body temperature exaxerbate muscle damage. conclusion the relatively low post-race concentrations of systemic and urinary markers of muscle damage and inflammation,5 when compared with those reported following road running events of similar duration,15 are attributed to softer underfoot surfaces, large fluctuations in pace of running and varied muscle recruitment patterns over the widely differing terrains.1 the sporadic increases in intensity of effort, rises in tintest, substantial body mass loss and increases in serum osmolality during the event, did not confirm previous suggestions3,4,11 that thermal and hydration status is directly related to the degree of muscle damage. it would be of interest to the investigate the impact of pre-race preparation on markers of muscle damage and inflammatory response found following this multi-day trail running event and to control the nutritional and fluid intake in future field work on multiday trail running. acknowledgements special thanks are extended to: • ms heidi mocke and the wildlands conservation trust for permitting the collection of these data at the 2011 three cranes challenge multiday trail run and for providing the research team with accommodation in the ‘race village’ located in the bushwillow campsite. they are also thanked for provision of the topographical data re the altitude gains and deficits during the race. • ergonomics technologies, pretoria and the mrc research unit for exercise science and sports medicine for the loan of cor temp data recorders which made the continuous monitoring of hr and tintest possible. • professor aj mckune and mr d naicker for their support with the field side collection of data reported in this paper. • ampath laboratories for its assistance with phlebotomy and chemical pathology. • the sa weather office for provision of precise data regarding the environmental conditions during the different stages of the race. • asokaran rajh for assistance with graphic artwork. references 1. millet gy, tomazin k, verges s, et al. neuromuscular consequences of an extreme mountain ultra-marathon. plos one 2011;6(2):e17059. 2. nieman dc, dumke cl, henson da, mcanulty sr, gross sj, lind rh. muscle damage is linked to cytokine changes following a 160-km race. brain, behav immun 2005;19:398-403. 3. casa dj, stearns rl, lopes rm. influence of hydration on physiological function and performance during trail running in the heat. j athl tr 2010;45:147-156. 4. stearns rl, casa dj, lopes rm. influence of hydration status on pacing during trail running in the heat. j strength cond res 2009;23:2533-2541. 5. clarkson pm, hubal mj. exercise-induced muscle damage in humans. am j phys med rehab 2002;81(suppl):s52-s69. 6. friden j, lieber r. eccentric exercise-induced injuries to contractile and cytoskeletal muscle fibre components. acta physiol scand 2001;171:321-326. 7. proske u, morgan dl. muscle damage from eccentric exercise mechanism, mechanical signs, adaptation and clinical application. j physiol 2001;537(2):333-345. 8. eston rg, mickleborough j, baltzopoulos v. eccentric activation and muscle damage: biomechanical and physiological considerations during downhill running. br j sp med 1995;29(2):89-94. 9. clarkson pm, kearns ak, pouzier p, rubin r, thompson d. serum creatine kinase levels and renal function measures in exertional muscle damage. med sci sports exerc 2006;38(4):623-627. 10. noakes td, myburgh kh, du plessis j, et al. metabolic rate, not percent dehydration, predicts rectal temperature in marathon runners. med sci sports exerc 1991;23:443449. 11. cleary ma, sweeney la, kendrick zv, sitler mr. dehydration and symptoms of delayed-onset muscle soreness in hyperthermic males. j athl tr 2005;40(4):288-297. 12. durnin jvga, womersley j. body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. br j nutr 1974;32:77-97. 13. singh n, denissen ec, mckune aj, peters em. intestinal temperature, heart rate and hydration status in multiday trail runners. cl j sports med . 2012. in press. 14. fox iii sm. naughton, jp, haskell wl. physical activity and the prevention of coronary heart disease. ann clin res 1971;3:404-432. 15. lewis sm, bain bj, bates i. dacie and lewis practical haematology. 10th ed. usa: churchill livingstone, 2006:11-25. 16. peters em, anderson r, theron aj. attenuation of increase in circulating cortisol and enhancement of the acute phase protein response in vitamin c-supplemented ultramarathoners. int j sports med 2000; 120-126. 17. knechtle b, kohler g. running 338 kilometres within five days has no effect on body mass and body fat but reduces skeletal muscle mass – the isarrun 2006. j sports sci med 2007;6:401-407. 18. middleton n, george k, whyte g, gaze d, collinson p, shave r. cardiac troponin t release is stimulated by endurance exercise in healthy humans. j am coll cardiol 2008:52(22):1813-1816. 19. leers mp, schepers r, baumgarten r. effects of a long-distance run on cardiac markers in healthy athletes. clin chem lab med 2006;44(8):999-1003. 20. la gerche a, connelly ka, mooney dj, macisaac ai, prior dl. biochemical and fctional abnormalities of left and right ventricular function after ultra-endurance exercise. heart 2008;94:860-866. 21. peake j, nosaka k, suzuki k. inflammation and eccentric exercise. exerc immunol rev 2005;11:64-85. 22. paulsen g, egner im, drange m, et al. a cox-2 inhibitor reduces muscle soreness, but does not influence recovery and adaptation after eccentric exercise. scand j med sci sports 2010;20(1):e195-207. 23. armstrong la, pumerantz kc, roti mw, kavouras sa, casa dj, maresh cm. human hydration indices. acute and longitudinal reference values. int j sport nutr exerc met 2010;20:145-153. sajsm 595 (commentarty).indd commentary 1 sajsm vol. 29 2017 targeting sedentary behaviour for behavioural change: opportunities for new strategies p j-l gradidge, msc, phd centre for exercise science and sports medicine (cessm), faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: p j-l gradidge (philippe.gradidge@wits.ac.za) sedentary behaviour is defined as time spent sitting during waking hours, particularly a metabolic equivalent (met) level of “energy expenditure ≤1.5 times the metabolic rate while in the sitting or reclining position”.[1] most of this sedentary behaviour occurs within the context of activities of daily living. instruments used to measure sedentary behaviour can vary in different regions, such as the sedentary behaviour questionnaire which captures time spent in various types of sedentary activities. however, in the south african context researchers may need to adapt items for the appropriate culture or language. this suggests that there is need for standardised sedentary behaviour instruments and nomenclature that address the paradox of sitting time in south africa. recently, sitting time has been shown to be strongly and independently associated with all-cause mortality in persons, even after adjusting for physical activity time.[2] only the most physically active persons were “protected” from the increased risk associated with sedentary behaviour. on average, south africans have a high level of sedentary time, [3] and the economic growth of the country has made the purchasing of sedentarypromoting assets more affordable for the large majority, including internet accessible devices. there is little understanding of how this transition influences health outcomes for this country. with the global shift of people into various centres of activity, and the continual development of web-based applications, the majority of global populations is now characterised by increased sitting times. urbanised populations are often nudged into sedentary thinking patterns by well-planned marketing strategies in the form of audiovisual stimuli to influence this behaviour.[4] the working environment is not dissimilar, and sitting for extended periods can be viewed as fundamental to worker productivity by line managers.[5] in south africa, the proportion of internet users actively engaged in accessing the internet is increasing at a rapid rate. recent data show that the proportion of internet users in the country has increased from 8% of the total population in 2006 to 52% in 2016.[6] the social media platform has also grown substantially, so that the majority of people connected to the internet do so via mobile devices.[7] the national development plan 2030, adopted by the south african government, includes information, technologies and communication (ict) as part of its priorities.[8] the vision for the ict sector of the country is to enhance the current infrastructure and reduce the “digital divide”. government has pledged to provide financial support for this initiative, and is in favour of lowering connectivity costs and improving ict standards. although policies to improve technological infrastructure may lead to a united country, these could have unintended health consequences, such as increasing the sitting time while connected to the internet. supportive mechanisms for behaviour change the private healthcare sector of south africa demonstrates that incentivised programmes can assist with obesity reduction in the country by rewarding healthy behaviours.[9] for those in the higher income categories, this may be in the form of digital healthcare and wearable devices which have provided the healthcare industry with evidence of adherence to such programmes. however, these data are usually delivered through internet-based applications which may result in increased sedentary time whilst connected to the internet. another dilemma is that most south africans still do not have adequate access to healthcare which can sometimes result in unintended consequences. for example, in 2009 one of the largest private healthcare providers in south africa launched an incentivised programme to encourage purchases of healthier food products with the intention of lowering bmi; however, this programme was shown to be regressive because the target population already has access to private healthcare while the public health care sector has no comparable programmes.[10] similarly, access to fitness facilities does not necessarily have an inverse linear relationship with obesity, and neither can dietary recommendations guarantee positive outcomes for disease reduction. the fact that the obesity epidemic in south africa continues to worsen suggests that incentive-based programmes alone may not be the best answer for the reversal of this epidemic. in a country undergoing a rapid internet-based transition, it is even more important to explore plausible solutions for sustainable behaviour change. contextualised solutions the recent evidence from the series in the lancet on physical activity confirms that sitting time is associated with obesity and related cardiovascular disease risk, but this relationship can be weakened with physical activity. [2] sedentary behaviour is composed of various interconnected constructs, and the understanding of how these components interact with each other is limited. it is also important to identity the effects of these respective indicators on cardiovascular disease. background: the south african online population is rapidly transforming into one which is always reachable. the economic benefits of this transition are vast; however, the impact on obesity and related diseases is potentially devastating discussion: in this commentary it is proposed that public health strategies be revisited to align with the contemporary digital evolution, particularly as increased web-based applications suggest higher amounts of sitting times. conclusion: it is necessary to gain a better understanding of the different domains of sedentary behaviour, and the manner in which they interact, to begin to develop strategies to reduce sitting time, and thereby reduce cardiovascular disease risk. keywords: internet; health; obesity; south africa; intervention s afr j sports med 2017; 29:1-2.doi: 10.17159/2078-516x/2017/v29i0a1632 mailto:philippe.gradidge@wits.ac.za http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1632 commentary sajsm vol. 29 2017 2 the following recommendations can assist with managing the problem of continuous screen time during waking hours:  the current public health solutions aimed at addressing obesity are prescriptive and not well-maintained. it is therefore recommended that interrupted screen time with less sitting be encouraged in workplaces, particularly in those industries that necessitate adherence to web-based services. in the home, an attitude towards lowering sedentary time could be shaped with supplemented physical activities within the family.  the next recommendation is more complex as it requires a complete paradigm shift towards active commuting. some south african cities have already started to alter the road infrastructure to encourage travel-related physical activity; however, these routes have not been maintained and, in some instances, dedicated cycle lanes are used for normal road traffic. the concept of active commuting can also be influenced by urban planners to reduce vehicular congestion in the major cities. since many people in south africa currently use public transport,[11] walking to a destination might be the healthy alternative, provided that it can be done in safety.  the internet has evolved rapidly over time and the emergence of web-based applications has narrowed the rift of societal diversity in south africa. the solutions for addressing sitting time within this construct needs to encompass all spheres of society, age and socioeconomic strata. for example, the higher socioeconomic stratum already engages in exercise programmes using tracking applications that provide virtual rewards for achieving monthly training objectives. developers of such applications and public health experts can follow this example by proposing similar rewards-based programmes to all population groups.  finally, behavioural economists use game theory to test real world social situations to assist with convergence towards certain behaviours such as purchasing preferences with regard to online shopping. policymakers can use these and other comparable evidence-based strategies to influence positive behavioural change in internet users. these strategies must be closely monitored to ensure sustainability and success. in the south african context, this is particularly important given the growing demand for web-based services and the recent focus on the rise of cardiovascular disease risk factors. conclusion further investigation of the various domains of sedentary behaviour is recommended to fully understand the impact of internet based screen time on cardiovascular disease in the context of an expanding base of internet connected people. references 1. sedentary behaviour research network. letter to the editor: standardized use of the terms "sedentary" and "sedentary behaviours". appl physiol nutr metab 2012;37(3):540-542. [http://dx.doi/10.1139/h2012-024] 2. ekelund u, steene-johannessen j, brown wj, et al. does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? a harmonised meta-analysis of data from more than 1 million men and women. lancet 2016;388(10051):1302-1310. [http://dx.doi/10.1016/s01406736 (16)30370-1] 3. shisana o, labadarios d, rehle t, et al. the south african national health and nutrition examination survey, 2012: (sanhanes–1): the health and nutritional status of the nation.pretoria: hsrc press, 2014. http://www.hsrcpress.ac.za/product.php?productid=2314&cat=0&page=1&fea tured&freedownload=1 4. basch ch, kecojevic a, cadorett v, et al. sedentary images in a popular us based parenting magazine: 2010-2015. health promot perspect 2016;6(2):55-57. [http://doi.org/10.15171/hpp.2016.10] 5. gardner b, smith l, mansfield l. how did the public respond to the 2015 expert consensus public health guidance statement on workplace sedentary behaviour? a qualitative analysis. bmc public health 2017;17(1): 47. [http://10.1186/s12889-016-3974-0] 6. the world bank group. internet users (per 100 people). washington, dc: the world bank group, 2016. http://data.worldbank.org/indicator/it.net.user.p2 (accessed 13 february 2017) 7. world wide worx, ornico. sa social media landscape 2017. http://www.worldwideworx.com/wp-content/uploads/2016/09/social-media2017-executive-summary.pdf (accessed 13 february 2017) 8. south african government. executive summary. national development plan 2030: our future – make it work. pretoria: national planning commission, 2012. http://www.gov.za/issues/national-development-plan-2030 9. lambert ev, kolbe-alexander tl. innovative strategies targeting obesity and non-communicable diseases in south africa: what can we learn from the private healthcare sector? obes rev 2013;14(suppl 2):141-149. [http://dx.doi/10.1111/obr.12094] 10. sturm r, an r, segal d, et al. a cash-back rebate program for healthy food purchases in south africa: results from scanner data. am j prev med 2013;44(6):567-572. [http://10.1016/j.amepre.2013.02.011] 11. lombard m, cameron b, mokonyama m, et al. report on trends in passenger transport in south africa. midrand: development bank of south africa, 2007. http://www.dbsa.org/en/aboutus/publications/documents/report%20on%20trends%20in%20passenger%20 transport%20in%20south%20africa.pdf (accessed 17 march 2017) http://www.hsrcpress.ac.za/product.php?productid=2314&cat=0&page=1&featured&freedownload=1 http://www.hsrcpress.ac.za/product.php?productid=2314&cat=0&page=1&featured&freedownload=1 http://www.worldwideworx.com/wp-content/uploads/2016/09/social-media-2017-executive-summary.pdf http://www.worldwideworx.com/wp-content/uploads/2016/09/social-media-2017-executive-summary.pdf http://www.gov.za/issues/national-development-plan-2030 http://www.dbsa.org/en/about-us/publications/documents/report%20on%20trends%20in%20passenger%20transport%20in%20south%20africa.pdf http://www.dbsa.org/en/about-us/publications/documents/report%20on%20trends%20in%20passenger%20transport%20in%20south%20africa.pdf http://www.dbsa.org/en/about-us/publications/documents/report%20on%20trends%20in%20passenger%20transport%20in%20south%20africa.pdf introduction heart rate variability (hrv), blood pressure variability (bpv) and baroreceptor sensitivity (brs) are often used as measures of autonomic activity, even though reported results are not always comparable or as expected. it is known that endurance athletes have lower average resting heart rates than non-exercising individuals. 33, 50 however, other exercise-induced autonomic influences on cardiac control are far more controversial. autonomic control via sympathetic and parasympathetic modulation of the heart has been assessed by power spectral analysis of hrv 1,7,33,41,46,48,50 and bpv. 44,52 different frequency peaks reflect specific physiological stimuli and it is possible to estimate the involvement of the autonomic nervous system (ans) influence and balance in heart rate (hr) regulation. 1,2,6 with power spectral analysis of hr, two characteristic peaks between 0.04 hz and 0.15 hz (a) and between 0.15 hz and 0.5 hz (b) are used to quantify the autonomic balance in terms of the low-frequency (lf)/ high-frequency (hf) ratio. 1,6,48 peak a is found in the region of mayer waves (0.1 hz) and is situated in the so-called lf area. it appears to be linked to the combined activities of the sympathetic and parasympathetic branches of the ans. peak b is synchronous with respiration, reflects vagal activity, is situated in the so-called hf area review autonomic response to exercise as measured by cardiovascular variability abstract motivation. there is growing interest in the use of cardiovascular variability indicators as measures of autonomic activity, even though reported results are not always comparable or as expected. this review aims to determine the consistency of results reported on the autonomic response to physical exercise as measured by heart rate variability, blood pressure variability and baroreceptor sensitivity. method. an ovid medline database search for the period 1950 march 2008 produced 46 articles for review. the published articles that evaluate the effect of exercise on the autonomic nervous system (ans) are summarised in three categories: the response of the ans during a bout of exercise, directly after exercise (recovery measurements), and after a long-term exercise programme. results. articles on the effect of training on the ans as measured by cardiovascular variability indicators show increased variability, decreased variability, and no change in variability. conclusion. findings in this review emphasise that standardisation and refinement of these measuring tools are essential to produce results that can be repeated and used as reference. standardisation is essential as these measurements are increasingly employed in studies regarding investigations of central autonomic regulation, those exploring the link between psychological pro cesses and physiological functioning, and those indicating ans activity in response to exercise, training and overtraining. this review shows that important aspects are inter-individual differences, duration and intensity of the exercise programme, and choice and specific implementation of variability analysis techniques. correspondence: mrs c c grant section sports medicine university of pretoria tel: 27 12 3624496 fax: 27 12 3623369 e-mail: rina.grant@up.ac.za c c grant (msc)1 j a ker (mb chb, mmed (int), md)2 1section sports medicine, university of pretoria 2department of internal medicine, university of pretoria 102 sajsm vol 20 no. 4 2008 fig. 1. summary of the ovid medline database search. autonomic nervous system (physiology) baroreflex (physiology) exercise 27118 articles 2084 articles 38434 articles 463 articles or and exclude: not english not human 340 articles select studies using hrv, bpv and brs as ans indicators 46 articles fig. 1. summary of the ovid medline database search. and also gives an indication of respiratory sinus arrhythmia (rsa). 1,48 during measurement of systolic bpv the lf peak corresponds with sympathetic activity while the hf peak is determined by mechanical effects of respiration on intrathoracic pressure and cardiac filling. 44,52 the variability in blood pressure and identification of the corresponding physiological stimuli are difficult to identify. indications are that the very low frequencies (≤0.04 hz) are influenced by vascular tone, endothelium factors and thermoregulation, and the lf peak (0.07 0.15 hz) relates to sympathetic activity and represents vasomotor tone. 2 brs reflects mainly vagal modulation of the hr by the arterial baroreceptors and the magnitude of response in heart beat interval to a change in blood pressure (ms/mmhg). 6 physical exercise requires rapid and complex physiological adaptation, particularly by the ans. exercise programmes require changes in the neural cardiovascular and ans control that are unique to the person and his/her surroundings. this review aims to determine the consistency of results reported on the autonomic response to physical exercise as measured by hrv, bpv and brs. method an ovid medline database search was conducted for the period 1950 march 2008 (fig. 1). the term ‘ans (physiology)’ produced 27 118 articles, and ‘baroreflex (physiology)’ 2 084 articles. when linking the results with the term ‘exercise’ (38 434 articles) and then limiting the results to ‘humans and english’, 340 references were found. only articles that used hrv (determined by time-domain analysis, poincaré analysis and/or frequency-domain analysis), non-invasive bpv and brs as indicators of autonomic function were selected, yielding 46 articles. results published articles on the effect of exercise on the ans as measured by hrv and bpv are summarised in three categories: the response of the ans measured during a bout of exercise, 3,5,14,16,26,29,37,42,43,51 and directly after a bout of exercise (recovery measurements), 3,9,2224,28,40,49 and the long-term effect of regular exercise on the ans. 4,8,10-13,15,17,18,19-21,25,27,30-32,34-36,38,39,45,47 the results of 10 articles on ans response measured during exercise are shown in table i. some authors expressed concern about the measurement of spectral analysis of hrv during exercise, while others reported increases (↑), decreases (↓) and no changes in variability indicators (↔) of sympathetic (sns) and parasympathetic (pns) influence. table ii shows results of 10 articles on the response of the ans measured after a bout of exercise (recovery measurements). comments found were based on time domain, spectral and coarsesajsm vol 20 no. 4 2008 103 table i. articles on the response of the ans measured during a bout of exercise reference number author/s title cardiovascular variability indicator 43 sandercock et al. the use of hrv measures to results from spectral analysis assess autonomic control of hrv not as expected; more during exercise research needed: word of caution 5 banach et al. hrv during incremental cycling spectral and time domain exercise in healthy, untrained analysis of hrv young men ↓sdnn, rmssd ↓lf, hf; lf/hf ↓ptot 16 freeman et al. ans interaction with the cv encourage the use of hrv at system during exercise rest and during exercise 14 eryonucu et al. the effect of ans activity on used spectral analysis of hrv in a exaggerated blood pressure comparative study response to exercise: evaluation by hrv 29 lucini et al. analysis of initial autonomic spectral analysis of hrv adjustments to moderate ↑lf suggest ↑sns exercise in humans ↓hf suggest ↓pns ↔ and ↑lf of bpv 42 saito and nakamura cardiac autonomic control and spectral analysis of hrv muscle sympathetic nerve ↓lf power, ↓ hf power, activity during dynamic exercise ↔total power ↑lf/hf: sns↑ ↓hf/ptot : pns↓ 26 kamath et al. effects of steady-state exercise spectral analysis of hrv on the power spectrum of hrv ↓lf,↓hf, sns↓, pns↓ 3 arai et al. modulation of cardiac autonomic spectral analysis of hrv activity during and immediately ↓hf after exercise ↓lf 51 yamamoto et al. autonomic control of hr during spectral analysis of hrv exercise studied by hrv ↓hf: pns↓ spectral analysis ↑and↔lf/hf:↑ and ↔sns 37 perini and veicsteinas hrv and autonomic activity at rest spectral analysis of hrv and during exercise in various no change in hf and lf physiological conditions power during increased loads ↔hf, ↔lf lf = low frequency; hfr = high frequency; sdn = standard deviation of all intervals; ptot = total frequency power; pnn50 = percentage of successive interval differences greater than 50ms; sns = sympathetic nervous system; pns = parasympathetic nervous system; sap = systolic arterial pressure. graining analysis of hrv and brs via the sequence technique and spectral analysis of bpv. table iii summarises findings on the long-term effect of regular exercise on the ans. some of the different techniques used to estimate cardiovascular variability were time domain and spectral analysis of hrv, brs via sequence technique and the alpha index, spectral analysis of brs and also brs via the slope of the baroreflex sequences and transfer function gain. discussion articles published on cardiovascular variability measured during exercise concluded that the interpretation of variability measurements is difficult because indicators reflecting sympathovagal interactions at rest do not behave as expected during exercise and that the increased respiratory effort had a confounding effect on hf bands. 43 it is also suggested that the presence of cross-sectional differences between hrv in athletes and non-athletes should be noted and that one should not use hrv data to determine autonomic control during exercise. doubt was expressed on the applicability of the hrv power-spectrum analysis, with its present interpretation, to assess the sympathovagal interaction during exercise. 5 however, other authors encouraged the use of hrv components at rest and during exercise as prognostic indicators, but called for the refinement of exercise measurements. 16 eryonucu et al. used hrv as an indicator of ans activity before, during and after exercise in a comparative study. 14 two other studies reported increased sympathetic influence (measured by lf and lf/hf) on autonomic cardiac control during graded exercise, 29,42 including increased, peripheral, vascular sympathetic activation at 30% of maximum exercise in the study by saito and nakamura. 42 these results were in direct conflict with studies indicating significant suppression of both sns and pns autonomic cardiac control during graded exercise measured by the lf and hf of the power spectrum of hrv. 3,26 in 1991 yamamoto et al. 51 reported decreased pns activity (hf) and unchanged sns activity (lf/hf) up to 100% of the predetermined ventilatory threshold (tvent), with an abrupt increase in sns activity (lf/hf) only at 100% tvent. perini and veicsteinas 37 concluded that changes in hf and lf power and in lf/hf observed during exercise do not reflect the decrease in vagal activity and the activation of the sns at increasing loads; neither did fitness level, age and hypoxia have any influence. however, exercising at medium-high intensities in the supine position did produce measurable increased power in lf. cardiovascular variability measured during recovery from a single bout of endurance exercise indicated that the total power of hrv 104 sajsm vol 20 no. 4 2008 table ii. articles on the response of the ans measured directly after a bout of exercise (recovery measurements) reference number author/s title cardiovascular variability indicator 24 heffernan et al. cardiac autonomic modulation spectral analysis of hrv during recovery from acute after endurance: endurance v. resistance exercise ↔total power, ↑lf/hf, after resistance: ↓total power of hrv, ↑lf/hf 49 terziotti et al. post-exercise recovery of autonomic spectral analysis of hrv and bpv cardiovascular control: a study by ↑lf of systolic blood pressure spectrum and cross-spectrum analysis ↓hf activity of heart rate ↓decreased brs in humans 22 hayashi et al. cardiac autonomic regulation after coarse-graining spectral analysis of hrv moderate and exhaustive exercises ↓hf ↑lf/hf 40 raczak et al. cardiovagal response to acute time domain and spectral analysis mild exercise in young healthy subjects of hrv and brs ↑sdnn ↔lf and hf ↓brs 26 kamath et al. effects of steady state exercise spectral analysis of hrv on the power spectrum of hrv ↑lf activity 23 heffernan arterial stiffness and baroreflex brs via the sequence technique sensitivity following bouts of aerobic ↓brs after resistance and aerobic exercise. and resistance exercise greater reduction after resistance 9 brown and brown resting and post-exercise cardiac time domain and spectral analysis of hrv autonomic control in trained ↓sdrr , ↓total power, ↓hf. master athletes ↔lf 28 lucini et al. selective reductions of cardiac spectral analysis of hrv and bpv autonomic responses to light bicycle hrv decreases with age exercise with aging in healthy humans brs via sequence technique 15 figueroa et al. endurance training improves spectral analysis of hrv post-exercise cardiac autonomic brs via sequence technique modulation in obese women ↑hf, lf, brs with and without type 2 diabetes 3 arai et al. modulation of cardiac autonomic spectral analysis of hrv activity during and immediately ↓hf, ↓lf after exercise lf = low frequency; hfr = high frequency; sdn = standard deviation of all intervals; ptot = total frequency power; pnn50 = percentage of successive interval differences greater than 50ms; sns = sympathetic nervous system; pns = parasympathetic nervous system; sap = systolic arterial pressure. sajsm vol 19 no. 4 2007 105sajsm vol 20 no. 4 2008 105 table iii. articles on the long-term autonomic effects of regular exercise cardiovascular reference number author/s name variability indicator 15 figueroa et al. endurance training improves post-exercise spectral analysis of hrv cardiac autonomic modulation in obese brs via sequence technique women with and without type 2 diabetes ↔hrv and brs: no baseline changes 47 spierer et al. exercise training improves cardiovascular spectral analysis of hrv and autonomic profiles in hiv brs via alpha index ↑brs increased ↑hf ↓lf/hf 4 aubert et al. low-dose exercise does not influence spectral analysis of hrv cardiac autonomic control in healthy ↔lf, hf, lf/hf sedentary men aged 55 75 years 31 martinelli et al. hrv in athletes and non-athletes at spectral analysis of hrv rest and during head-up tilt ↑sdnn ↔lf, hf: sns/pns↔ 45 sharma et al. short term physical training alters time domain and spectral cardiovascular autonomic response analysis of hrv amplitude and latencies ↔hrv indicators 37 perini and hrv and autonomic activity at rest and spectral analysis of hrv veicsteinas during exercise in various physiological fitness level has no influence conditions 10 buchheit and cardiac parasympathetic regulation: time domain and spectral gindre respective associations with cardiorespiratory analysis of hrv fitness and training load ↑hf, rmssd, pnn50 39 raczak et al. long-term exercise training improves time domain and spectral analysis ans profile in professional runners of hrv, spectral analysis of brs ↑sdnn, pnn50, rmssd, ↑total power and lf ↑brs 36 okazaki et al. dose-response relationship of endurance spectral analysis of hrv training for autonomic circulatory control brs via transfer function gain in healthy seniors ↑sdrr, lf, hf ↑brs 32 melo et al. effects of age and physical activity on time domain and spectral the autonomic control of heart rate in analysis of hrv healthy men ↑rmssd ↓hr 19 goldsmith et al. exercise and autonomic function review ↑sns activity ↓pns activity 17 goldsmith et al. physical fitness as a determinant spectral analysis of hrv of vagal modulation ↑hf 27 kiviniemi et al. cardiac vagal outflow after aerobic training spectral analysis of hrv by analysis of high-frequeny oscillation ↑hf of the r-r interval 12 cooke et al. effects of training on cv and sympathetic time domain analysis of hrv, brs responses to valsalva’s maneuver ↑sdrr ↑brs 13 costes et al. influence of exercise training on brs via the slope of the baroreflex cardiac brs in patients with copd sequences between systolic blood pressure changes ↑brs 34 monahan et al. regular aerobic exercise modulates brs via linear regression between age-associated declines in cardiovagal bp en rr intervals during baroreflex sensitivity in healthy men a valsalva maneuver ↑brs 11 carter et al. effect of endurance training on autonomic review control of heart rate – review ↓sns activity ↓pns activity 25 iellamo et al. conversion from vagal to sympathetic spectral analysis of hrv predominance with strenuous training brs via the sequences method in high-performance athletes 100% training load reverse effects: ↑lf,↓hf, brs↓ 8 bowman et al. effects of aerobic exercise training and brs via the alpha index yoga on the baroreflex in healthy ↔brs elderly persons did not alter compared with significantly reduced total power found after resistance exercise. however, the lf/hf ratio was significantly increased after both resistance and endurance exercise, indicating increased sns (lf) and/or decreased pns (hf) influence. 24 this corresponds with results published by terziotti et al., who found a reduced hf (vagal) component of hr and decreased brs during 15 minutes of recovery. 49 another study 22 also found suppressed vagal (hf) activities 10 minutes of recovery after 100% of the individual ventilatory threshold compared with baseline values. raczak et al. found no differences in hf and lf activities between preand post-exercise measurements, but increased brs and overall hrv as measured by standard deviation of all intervals (sdnn) after exercise. 40 however, kamath et al. 26 and figueroa et al. 15 reported significant increased lf power during post-exercise recovery. this contrasts with findings by arai et al., who reported significantly decreased hr power at all frequencies compared with baseline values in normal subjects. 3 decreased brs and hrv after exercise were also reported in other studies. 9,23 lucini et al. reported that ageing progressively reduces the cardiac autonomic excitatory response to light exercise. 28 articles on the effect of an endurance training programme over a period of time also showed a wide range of results. one study 15 reported no change in baseline brs and hrv values after a 16week fitness programme, while another found increased brs when comparing fitness levels. 47 aubert et al. also found no evidence of significant changes in resting autonomic modulation of the sinus node after a low-volume, moderate-intensity 1year exercise programme. 4 comparing 11 young sedentary participants and 10 endurance-trained cyclists martinelli et al. found no difference in power-spectral components of hrv at rest. 31 however, a lower hr and higher values for time domain hrv indicators were reported during rest and head-up tilt, concluding that resting bradycardia seems to be more related to changes in intrinsic mechanisms than to ans control modifications. sharma et al. found no statistically significant changes in autonomic cardiovascular control measured by hrv after a physical training programme of 15 days. 45 perini and veicsteinas 37 reported no influence of factors such as age and fitness level, while bucheit and gindre 10 showed that modifications in autonomic activities induced by training are visible in hrv power spectra at rest. rackzak et al. 39 reported pns dominance by measuring hrv and increased brs after long-term exercise training. another study 36 reported increased hrv and brs in masters athletes compared with decreased values for sedentary seniors. several other studies also concluded that regular physical activity increases vagal influence on the hr and brs, while the sympathetic tone may be decreased. 8,11-13,17,19,25,27,32,34 however, iellamo et al. 25 found a reversal of these effects after a period of training at 100% training load. very intensive training shifted the cv autonomic modulation from pns toward sns predominance. increases were reported in all components of hrv after a 1-year exercise training programme in children who initially had low hrv. 35 in 2001 pigozzi et al. 38 found that a 5-week exercise training period in female athletes increased the sns cardiac modulation, which may coexist with relatively reduced or unaffected vagal modulation. gulli et al. 20 reported increased lf reactivity (sns) and brs after a moderate aerobic training programme in older women. in 1992 goldsmith et al. 18 noted that, although exercise training may increase pns activity, studies report conflicting results. as seen from the above summary, nearly two decades later conflicting results persist when the effects of exercise training on the ans is measured during exercise, directly after exercise and after a long-term exercise programme. possible confounding factors mentioned and identified are listed in table iv. a possible explanation for conflicting results is that the individual’s response is greatly influenced by the baseline cardiovascular autonomic function, thus producing large inter-subject variation in the 106 sajsm vol 20 no. 4 2008 table iii. articles on the long-term autonomic effects of regular exercise – continued 35 nagai et al. moderate physical exercise increases spectral analysis of hrv cardiac ans activity in children with low hrv ↑lf, ↓hf 38 pigozzi et al. effects of aerobic exercise training on 24hr time domain and spectral profile of hrv in female athletes analysis of hrv ↔time domain ↔lf, hf (daytime) 20 gulli et al. moderate aerobic training improves spectral analysis of hrv and bpv autonomic cv control in older women ↑brs ↑lf (rr), lf (sap) 18 goldsmith et al. comparison of 24-hour parasympathetic report conflicting results activity in endurance-trained and spectral analysis of hrv untrained young men ↑hf 21 hautala et al. cardiovascular autonomic function correlates baseline vagal (hf) influences with the response to aerobic training in determines effect of exercise training healthy sedentary subjects lf = low frequency; hfr = high frequency; sdn = standard deviation of all intervals; ptot = total frequency power; pnn50 = percentage of successive interval differences greater than 50ms; sns = sympathetic nervous system; pns = parasympathetic nervous system; sap = systolic arterial pressure. table iv. possible confounding factors inter-individual variation baseline cardiovascular autonomic function age gender fitness bmi diet alcohol consumption smoking analysis techniques time and frequency domain measures do not describe non-linear features in hr behaviour use of da, apen length of sampling time (tachogram) training/exercise length of training period intensity of training type of exercise: resistance or endurance sajsm vol 20 no. 4 2008 107 conventional non-spectral and spectral measures of cardiovascular variability. hautala et al. 21 suggested that high vagal activity at baseline is associated with improvement in aerobic power caused by aerobic exercise training. we also observed that some studies used non-homogeneous participant groups with regard to age, gender and bmi, while others did not include these in the participant description. factors often not taken into consideration are baseline blood pressure, blood cholesterol and diet. the effect of duration and intensity of the training programme as well as the type of exercise (endurance or resistance) may have been underestimated in studies on the ans and exercise. 24 in this review training periods from 15 days to 1 year were studied and the different degrees of exercise intensity used were not even mentioned in many articles. 22 the choice and specific analysis techniques implemented may also play a role in the observed conflicting results. the recommended sampling time (tachogram) for hrv analysis is 5 minutes, 48 but different time windows were selected by different authors – 5 minutes, 10 minutes, 15 minutes and 24 hours. the articles studied used mostly traditional measures of variability, such as time and frequency. however, it is known that non-linear phenomena are involved in cardiovascular control. therefore, the use of analysis techniques that acknowledge this fact should be co-implemented and reported with traditional measures. examples include the measurement of fractal scaling exponents (describes the fractal-like correlation properties of r-r interval data) and apen (quantifies the amount of complexity in the time series data). 30 conclusions this review demonstrates the wide variety of results published during the past decades on the effect of training on the ans as measured by cardiovascular variability indicators. it is clear from the results that standardisation and refinement of these measuring tools are essential to produce repeatable results that can be used as references in other studies. this is necessary as these measurements are increasingly employed in studies ranging from investigations of central autonomic regulation; to studies exploring the link between psychological processes and physiological functioning; to the indication of ans activity in response to exercise, training and overtraining. important aspects to consider when developing standardised procedures are inter-individual differences, duration and intensity of the exercise programme, and the choice and implementation of a specific variability analysis technique. much more research needs to be done to fully describe and accurately quantify the effect of exercise on the ans. references 1. akselrod s, gordon d, ubel fa, shannon dc, berger ac, cohen rj. power 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rl, rao ps. short-term physical training alters cardiovascular autonomic response amplitude and latencies. indian j physiol pharmacol 2004; 48(2): 165-173. 46. shin k, minamitani h, onishi s, yamazakih, lee m. autonomic differences between nonathletes: spectral analysis approach. med sci sports exer 1997; 29: 482-1490. 47. spierer dk, demeersman re, kleinveld j, et al. exercise training improves cardiovascular and autonomic profiles in hiv. clin j auton res 2007; 17: 341-348. 48. task force of the european society of cardiology and the north american society of pacing and electrophysiology. heart rate variability: standards of measurement, physiology interpretation and clinical use. circulation 2006; 93: 1043-1065. 49. terziotti p, schena f, gulli g, cevese a. post-exercise recovery of autonomic cardiovascular control: a study by spectrum and cross-spectrum analysis in humans. eur j appl phys 2001; 84(3): 187-194. 50. yamamoto k, miyachi m, saitoh t, yoshioka a, onodera s. effects of endurance training on resting and post-exercise cardiac autonomic control. med sci sports exerc 2001; 33(9): 1496-1502. 51. yamamoto y, hughson rl, peterson jc. autonomic control of heart rate during exercise studied by heart rate variability spectral analysis. j appl phys 1991; 71(3): 1136-1142. 52. zhang r, iwasaki k, zuckerman jh, behbehani k, crandall cg, levine bd. mechanism of blood pressure and r-r variability: insights from ganglion blockade in humans. j phys 2002; 543: 337-348. 32 sajsm vol 19 no. 2 2007 introduction the purpose of this review is to highlight concerns regarding the consequences of mild traumatic brain injury (mbti) (concussion) in the contact sports, including boxing, soccer, american football and rugby. acute and chronic effects of concussion are discussed against a background of literature that sheds light on the incidence of concussion in these sports. attention is drawn to individual implications, which in turn have societal ramifications in need of being acknowledged and researched. a way forward is proposed, including recommendations that apply specifically to the south african context. increasing participation in contact sports the popularity of the traditionally male-dominated contact sports is growing, 4 and of note is the increasing number of women who are participating in these sports. 6 a media report suggests that in the early years of this decade more than 2 000 women were already playing rugby football, and three women’s rugby football union world cups had taken place involving 12 countries. 5 in south africa an official launch tournament was held in 2001 to promote rugby union for women, 5 which is the rugby code followed in this country, as well as extensively in new zealand, australia and britain. at around the same time in south africa, legislation was drafted permitting women to participate in boxing, 42 a move that follows a worldwide trend. in the past decade there has also been an active drive to extend sporting facilities to previously disadvantaged or racially precluded groups in south africa. together these factors mean that there are significantly increasing numbers of individuals participating in contact sport in this country, including both males and females, and individuals of all races from high to low socio-economic status. accordingly, it appears important to evaluate the overall impact of exposure to head injury in these sports. incidence of head injury in contact sport incidence studies confirm that concussion is a common feature characterising the contact sports. whilst it is self-evident that boxing is associated with repeated head insults, the degree to which this is an aspect of the field contact sports of football, soccer and rugby needs to be more fully acknowledged. research on the incidence of concussion among american university-level football and soccer players during review article ethically we can no longer sit on the fence – a neuropsychological perspective on the cerebrally hazardous contact sports abstract background and objective. the number of male and female contact sport participants is increasing worldwide. the aim of the review is to discuss the potential for deleterious sequelae of sports concussion (mild traumatic brain injury (mtbi)), and management thereof. discussion. incidence of concussion in the field contact sports is high, not only for boxing, but also for soccer, football and especially rugby. an overview of studies investigating persistent deleterious cognitive and symptomatic outcome following cumulative sports mtbi suggests that individuals may be at risk for permanent neurological damage following participation in a contact sport. established sequelae of traumatic brain injury (tbi) typically involving frontal systems include cognitive decline, behavioural changes such as diminished self-regulation and aggression, and increased risk for alzheimer’s disease. the presence of such consequences hidden within the context of the widely popularised contact sports, has societal implications that should be acknowledged. compromised scholastic abilities and enhanced aggressive tendencies in association with sports mtbi are in need of further longitudinal research. conclusion. a comprehensive preventive approach to the management of mtbi in sport is advocated that includes professionally applied neuropsychological assessment as a crucial component. future policy considerations are the introduction of mandatory informed consent for participation in a high-risk contact sport such as rugby, particularly at youth level, and financial provision for concussion management amongst economically disadvantaged populations. correspondence: a b shuttleworth-edwards national sports concussion initiative psychology clinic rhodes university grahamstown 6139 tel/fax: 046-636 1296 e-mail: a.edwards@ru.ac.za a b shuttleworth-edwards (phd) v j whitefield (phd) psychology department, rhodes university, grahamstown pg32-38.indd 32 7/5/07 10:33:41 am sajsm vol 19 no. 2 2007 33 a single season reported figures of 34% and 46%, respectively. 11 of these, 100% of the football players and 75% of the soccer players had suffered more than one concussion in the season. due to the tackling manoeuvre in rugby union the rate of serious injuries in this sport is the highest among the rugby football sports; in particular there is a substantially higher rate of injury to the upper extremities, including the head and neck areas. 44 the world health organization (who) task force review revealed a higher rate of concussion for rugby union than rugby league, american football and soccer, being up to 8.0 per 1 000 game hours, compared with an upper limit of 3.0, 3.3 and 1.3 per 1 000 game hours respectively for the others. 8 studies on the contact sports in respect of gender generally indicate that females sustain around 50% fewer concussions than males. 8 with specific reference to rugby, a new zealand study 49 found that rugby union accounted for the highest rate of sports-related brain injury, with 30% of players reporting at least one concussion in a season of club rugby. in a south african study 35 concussion was reported to be the most prevalent injury in one season of high school rugby union making up 22% of all injuries, and another study 45 documented a lifetime incidence of 2.3 concussions (range 0 7) per top team rugby-playing schoolboy. in each of these three studies, the researchers considered the figures to be an underestimate of the true concussion incidence in rugby union, due to athletes’ common tendency to underreport, and the retrospective nature of the research. finally, it would appear that injuries in rugby union at the professional level have been on the increase, and despite rule changes (new zealand, australia and britain in the 1980s, and south africa in 1990), this trend has shown no sign of abating. 23 moreover, in addition to the number of formally reported concussions, it is suggested that athletes are likely to sustain multiple subconcussive insults due to player-to-player and player-to-ground collisions over long periods of exposure to these sports, that are likely to have cumulative effects. 24 subconcussive injury (microtrauma) refers to events similar to those giving rise to concussion, but involving smaller impact forces that operate below the threshold necessary to produce symptoms. in light of this phenomenon there is also growing concern about the extent to which heading in soccer is a source of cumulative microtrauma to the brain, an issue about which there is uncertainty and ongoing debate. 41 in sum, the figures from the studies cited above attest to the likelihood of an overall incidence of concussion of some magnitude (given the vast number of participants in these sports). the implications of this require careful evaluation on both the individual and societal levels. neuropsychological consequences of mtbi in contact sport in recent years there has been growing concern regarding the extent of neuropsychological (cognitive, emotional and behavioural) changes that are known to occur in association with mtbi, and their implications. more immediate acute sequelae typically resolve within 3 months post-injury, and effects that persist for longer than this are viewed as relatively intractable (i.e. chronic). 39 sequelae of traumatic brain injury (tbi), including mtbi, are non-specific in nature, and may include a number of symptoms varying in degree of severity depending on differential features of the injury (seriousness and location of the injury, and whether in the acute or chronic phase post-injury), all in interaction with the neurological and psychiatric predisposition of the injured individual. typically following mtbi, cognitive effects identified on the basis of objective testing include dysfunction in memory, learning and processing speed, implicating fronto-temporal involvement. 26 emotional and behavioural effects described are headache, dizziness, blurred vision, anxiety, depression, sleep disturbance, noise and light sensitivity, fatigue, and a cluster of symptoms that implicate frontal lobe involvement, including distractibility, impulsivity, disinhibition, argumentativeness, irritability, aggression, impaired judgment, general psychosocial dysfunction, executive dysfunction, and lowered selfmotivation. 16,26,39 in both the acute and chronic conditions such sequelae may be marked, or they may be subtle yet perniciously present, only becoming apparent under stressful conditions or increased task challenge. 12 a model of cognitive reserve has been proposed by researchers to account for the inconsistencies and variability amongst individuals who sustain tbis with similar levels of severity but where the outcome is different. 43 in terms of this model, individuals who are most vulnerable to the deleterious effects of mtbi will be those who start off with reduced cerebral capacity due to factors such as a prior learning disability, low iq, prior psychiatric disorder, and prior neurological damage including a prior head injury. accordingly, research reveals that the majority of individuals will not reveal any clinically detectable permanent disability following a single mbti. 39 however, it is generally accepted that a substantial proportion of around 10 30% of such individuals do sustain chronic disability, particularly those with prior vulnerability such as cognitive or psychiatric disability, a factor that mtbi researchers increasingly urge should not be downplayed or overlooked. 39,40 these researchers emphasise the potential for type ii error in group mtbi research (false-negatives), due to the confounding element of a substantial proportion of spared individuals in the cohort who serve to obscure the deleterious clinical picture for the relatively few who are significantly affected. further, in keeping with cognitive reserve theory, it was already apparent from an early seminal study that individuals with the additive effect of cumulative mild brain injury do reveal detectable neuropsychological disability on a long-term basis. 17 in support of this there has been a gathering weight of research across the spectrum of contact sports that points to permanent neurocognitive deficits demonstrated on objective testing, or symptomatic dysfunction based on self-reports, in players of these sports including soccer 50 , australian rules football, 10 american football 22 , and rugby union. 45 consistently, reviews point to problems being more pronounced in professional and pg32-38.indd 33 7/5/07 10:33:41 am 34 sajsm vol 19 no. 2 2007 older players with longer and/or more intensive exposure to the sport. 2,45 enhanced deficits in these older athletes is commensurate with cognitive reserve threshold theory, where the additive effect of repeated brain insults over a longer period of time has the effect of increasing vulnerability to symptom presentation. in addition to length of exposure, it is of note that genetic vulnerability plays a role in the development of chronic traumatic brain damage. research indicates that cognitive decline is more pronounced in older football players who carry the apolipoprotein e4 allele genotype. 25 commensurate with the cognitive reserve threshold model, 43 this study highlights the potential for significant individual variability in symptom presentation that may occur in additive fashion, depending on the presence or absence of this genetic factor, as well as the variety of other risk factors described above, including the presence of prior mtbi in itself. methodological evaluation of sports mtbi research for the most part sports mtbi studies that have compared sports groups with non-contact sports controls, have provided affirmation for the presence of deleterious effects in the target contact sport group. however, methodological criticism has been levied at some studies which have indicated that heading may be associated with deleterious effects, with the implication that outcome from these studies is only cautiously indicative of such effects. 41 in particular, criticism has been raised around the frequently cited soccer studies of matser and colleagues, 30,31 on the grounds of alcohol use being a potentially confounding factor in the soccer group, and the use of multiple measures without making the appropriate adjustments for type i error (finding significance purely by chance). however, a response to this criticism indicates that the issue raised in respect of alcohol was not justified, and an adjustment for type i error was made in matser’s second 1999 study by implementing more stringent significance levels. 31,32 further, a number of significant strengths were in evidence for this study, including strict control for level of education and the inclusion of sports-active controls. a number of other studies that point to neuropsychological compromise in the contact sports groups 41,45 similarly demonstrate methodological strengths, including control for education, iq and gender, the incorporation of a sports-active control group, and the inclusion of overall incidence of concussion as a variable. in contrast to multiple studies attesting to problems attributable to mtbi in contact sports groups (exemplified by those isolated for citation above), the present authors identified only 4 studies of comparative sports groups that did not support such deficits. 3,20,38,48 however, all of these studies demonstrate substantive methodological limitations, and therefore do not provide convincing counterbalancing evidence to refute the presence of deleterious effects affirmed in the other studies. for example, two of these studies had no control for iq, but in addition they used mixed male and female participants in their studies, constituting a serious confounding factor 3,20 (see discussion below on differential gender effects). the other two studies had very small subgroup numbers (mainly in the low to mid 20s) and were therefore prone to type ii error (failing to find significance when it does exist). 38,48 moreover one of these studies 48 was on very young athletes (aged 13 16 years), and in terms of the cognitive reserve threshold model, any problems in this cohort could be expected to be very subtle and in some cases subclinical. several of the studies cited above that are in support of deleterious effects due to participation in a contact sport, also have small subgroup sample numbers. however, small cohorts are mainly a limiting factor for studies that fail to demonstrate significant differences, due to the associated loss of statistical power that may result in failure of an investigation to reveal meaningful changes. in contrast, relatively well-controlled studies that demonstrate statistically significant differences in the hypothesised direction, in spite of small sample numbers, gain potency with the implication that larger sample numbers would be likely to reveal even more marked effects. studies that have investigated neuropsychological effects within a sports cohort in terms of number of reported concussions (rather than contact versus non-contact groups), also predominantly demonstrate long-term cognitive or symptomatic deficit in association with increasing numbers of concussions, 22,24 although there are a number of studies that do not do so. 21,28 on examination, however, all those studies with negative findings reveal methodological problems in that usually there is limited control for age, education, iq or gender, or all four of these potentially confounding variables. furthermore, no concussion-based studies with negative findings identified by the authors had any non-contact sport-control group. consequently all have the inherent confounding variable of unreported concussive or subconcussive episodes that may be present in the socalled zero concussion subgroups. this makes these studies particularly susceptible to type ii error, and in order to establish differences they would need to have provided more strongly contrasting concussion groups. accordingly, deleterious effects are supported on subgroups with 3+ concussions, 22 whereas those with negative findings have tended to investigate subgroups with a ceiling of only 1 or 2 concussions. 21,28 it is problematic that relatively isolated findings of negative effects with methodological problems such as outlined above, have been used to suggest that players of the targeted contact sports groups are safe from deleterious effects of multiple concussion. 20,28 findings such as these, which go against hypothetical expectations on theoretical and empirical grounds, need to be scrutinised rigorously for risk of type ii error (false-negative effects), before making premature suggestions in respect of falsification of the expected effects. 46 another interpretive error that has occurred in the literature, has been to cite results of studies on post-injury follow-up of concussed players demonstrating return to baseline levels pg32-38.indd 34 7/5/07 10:33:42 am sajsm vol 19 no. 2 2007 35 on cognitive tests, in order to suggest that athletes do not sustain persistent effects. 33 however, in the absence of noncontact sports controls, return to baseline does not rule out the possibility that such athletes were impaired prior to the latest concussion under investigation, and/or are benefiting from practice effects. gender issues of the many studies cited above that implicate persistent deleterious consequences in association with participation in a contact sport, most pertain to male athletes. two studies that have performed gender analyses on their sports cohorts provide support for the well-known fact that females and males perform differently on a number neurocognitive tests. 3,20 typically in terms of the literature, 26 females outperformed males on tests of visuoperceptual functioning 3 and there were mixed results in terms of gender superiority for memory. 3,20 two studies were identified that examined neurocognitive effects within exclusively female sports groups. 13,38 one study yielded negative findings in relation to heading in soccer for both males and females. 38 as already indicated above, this study comprised small sample numbers thus being prone to type ii error, therefore not ruling out the presence of heading effects for either group. the other study demonstrated visuoperceptual processing speed difficulties for female rugby players with concussions, 13 suggesting that the established female advantage in this area did not protect these athletes from acquired decrements in association with rugby-related mtbi. it appears that only one sports mtbi study has investigated symptomatic outcome with stratification for gender. 1 this study demonstrated that headache was present for both males and females, whereas females reported more symptoms of being dazed and dizzy and males more symptoms of blurred vision, numbness and tingling. in a study on persistent symptomatic outcome following mtbi in general, female vulnerability to late complaints was demonstrated, supporting findings of prior research, and was considered to have a possible organic component. 7 overall the gender indications from this review are that females have a lower risk of concussive injury in sport than males. furthermore, neurocognitive and symptomatic profiles differ for females compared with males, both in sports and more general contexts, and it appears that females may be at greater risk than males for persistent symptomatic problems post mtbi in general, of probable organic aetiology. of relevance here, also within the context of cognitive reserve threshold theory, is the common finding that female gender is a risk factor for alzheimer’s disease. 43 head injury is also a well-substantiated risk factor for alzheimer’s disease. 18 thus an implication from the cognitive reserve model is that when sports-related repetitive head injury is superimposed on the female brain with inherent pre-existing vulnerability to alzheimer’s disease, in additive fashion, this might further enhance the risk of a such a dementia in the female population. on the other hand, a counterbalancing protective factor might be that women play less intensively or collide at lower velocity than their heavier male counterparts, thus sustaining less severe effects. this supposition is supported by the literature cited above that confirms female concussion rates for elite-level participation in contact sports to be around 50% less than for males. 8 accordingly, in view of the differential empirical findings for gender (for rate of injury, neurocognitive test performance, symptomatic outcome and vulnerability factors), it is essential that research studies on the effects of concussion in contact sports not be investigated in mixed gender groups; rather there should be strict stratification for gender. youth and scholastic issues concern is being expressed about more immediate as well as long-term consequences of sports concussion that may easily go unacknowledged, and yet may translate into scholastic difficulties for the child, adolescent or university student. 34 cognitively such consequences include impairments in concentration, learning, and the ability to process information at speed which are known to occur after a mtbi for any period from days up to around 3 months. 14,26 examination dates at school and university may easily overlap with the continued presence of even quite short-term cognitive dysfunction in a sport-playing youth, and could make the difference between passing and failing in the borderline candidate, or the loss of a crucial scholarship for a bright scholar. it has been demonstrated that such effects may be perniciously subtle and out of the conscious awareness of the mildly concussed athlete albeit in evidence on objective testing, 27 and hence the more immediate post-concussion effects (within days and weeks of the injury) need to managed with due caution in terms of possible deleterious effects on an athlete’s scholarly activities. of relevance for youth-level participation in these sports, is that university football players with a history of two or more concussions and a learning disability reveal significantly worse performance on tests of executive function and speed of mental processing than those with a similar history of concussions and the absence of a learning disability. 9 a recent study provides compelling evidence for persistent neurocognitive difficulties in a sample of symptom-free high school athletes with two or more concussions. 34 this group was characterised by lower cumulative academic grade averages, and it is uncertain whether this was as a result of the concussion history, or a characteristic of those predisposed to concussion, or a combination of both of these factors. some researchers have emphasised that the identified cognitive deficits following sports mtbi are subtle and have not as yet been shown to be of consequence in the players’ everyday lives. 20 others emphasise how important it is that information on the cumulative and long-term effects of brain injury be communicated to young sports individuals, since a proportion of these individuals will have sustained what could be a permanent reduction in brain function prior to reaching maturity. 15 pg32-38.indd 35 7/5/07 10:33:42 am 36 sajsm vol 19 no. 2 2007 societal implications wide participation in contact sport at both youth and adult levels translates into very large numbers of individuals exposed to mtbi generally, and calls for an evaluation of possible consequences that go beyond the individual to the societal level. in particular, the possibility of increasing violence as a result of structural brain damage incurred through large-scale participation in cerebrally hazardous contact sports appears to have been overlooked, although this is an element that has been examined in relation to tbi in general. one-year estimates of irritability and temper following severe tbi reportedly range from 30% to 70%, and following mtbi from 5% to 70%. 47 one mtbi study showed that of those who did not suffer loss of consciousness, 21% presented with irritability. 47 accordingly ‘aggression on little or no provocation’ is proposed as a research criterion for post-concussive syndrome in the diagnostic and statistical manual (dsmiv). 37 furthermore, it has been demonstrated that tbi in childhood may result in pervasive deficits in self-regulation, social and behavioural functioning, 16 and frontal lobe damage in early life contributes to disability in the areas of insight, foresight, social judgement and empathy. 36 it appears from research that a risk factor for the development of aggressive behaviours may include a pre-injury history of irritability and aggression. 47 there is a high incidence of brain abnormality and/or a history of head injury amongst prisoners and people displaying antisocial behaviours, and a review of aggressive disorders reports that a small study of death-row inmates found a 75% history of tbi. 47 clearly, acquired brain damage identified in association with criminals and antisocial individuals would be the result of many causes, especially assault and motor vehicle accidents, and the intention here is not to suggest that sports participation is a predominant contributing factor to crime in our society. however, it is conceivable that for some people involved in cerebrally hazardous sports this may constitute a contributory effect. for example, it is probable that there will be an exacerbation of prior damage (from causes other than sport) in a proportion of individuals, through repeated mtbi sustained whilst participating in contact sports. furthermore, those athletes with more aggressive dispositions are the ones most likely to be drawn to participate in these relatively aggressive sports. in light of the research cited above on risk factors for aggressive behaviour following tbi, 47 these same individuals would constitute a subset susceptible to exacerbated aggressive tendencies, in association with damage to frontal systems that typically accompanies the concussive mtbi. preliminary support has been gained for this supposition from studies on rugby union, where symptoms of ‘argumentativeness’ and ‘aggression’ differentiated rugby groups from non-contact sport controls more robustly than any other symptom. 45 this may be a reflection of the rugby players being constitutionally more aggressive than the non-contact sports controls. however, the pervasiveness of this effect implies that there is an overlay of acquired argumentative/ aggressive traits due to repeated concussive incidents for a proportion of the rugby players in these studies. in sum, on a societal level it would appear logical to expect increased aggressive tendencies in association with repetitive sports mtbi in a proportion of athletes, and this may be a silent contributing factor to antisocial behaviour and criminal activity in society. further, exposure to repeated concussion has the potential to diminish brain power amongst the sector of our talented and not-so-talented youth who participate in these sports. finally, due to increased risk of alzheimer’s disease following head injury, the extent to which sports-related concussion may contribute to increased risk in this regard especially for females is a matter of concern, and in need of further research. epidemiological and longitudinal case-based studies are needed to substantiate the role of cerebrally hazardous sports in the development of the deleterious cognitive and behavioural changes described here, that may impact on an individual’s scholastic or social life, or increase susceptibility to cognitive deterioration with aging. conclusion in conclusion, the neuropsychological perspective presented here reveals concerns for deleterious effects on athletes in association with participation in contact sports, in the face of which health professionals can no longer afford to sit on the fence. there is growing evidence from research to support persistent problems in association with cumulative mtbi in association with the rugby football sports, at youth and adult levels. studies identified that are in opposition to this are in the minority, and have methodological limitations including a high risk for type ii error (false-negative results) that preclude any firm interpretations about the field contact sports being safe. in this situation, movement in the direction of the following actions would appear appropriate: (i) participation in the contact sports should occur only after properly informed consent has been given, especially in the case of children and adolescents, thereby providing an educative function and medico-legal protection to the sports body involved; (ii) comprehensive monitoring of every sports concussion case on an individualised basis should be implemented according to the consensus opinion arising out of the recent concussion management symposia, that discredits generalised management guidelines based on relatively arbitrary cut-off criteria; 19 (iii) neuropsychological assessment should be included as a crucial component of the overall management programme, incorporating computer-based pre-and post-concussion neurocognitive screening 19 (iv) such neurocognitive screening should be mandatory in schools that promote rugby due to a particularly high risk of concussion in the sport; (v) individualised return-to-play decisions, and advice on termination of participation in a contact sport, should be made with particular caution around vulnerability factors for deleterious outcome, such as prior concussions, cognitive dysfunction, psychiatric and neurological disability, pg32-38.indd 36 7/5/07 10:33:42 am sajsm vol 19 no. 2 2007 37 and persistent aggressive or antisocial tendencies where there is little or no provocation; and (vi) in cases where a decision on termination is proving to be particularly difficult for the athlete, and given available financial resources, consideration might even be given to investigation for the presence of the apolipoprotein e4 allele genotype. for best practice in the implementation of such returnto-play and termination decisions using computerised psychometric instruments, registered psychologists with training in clinical neuropsychology are called for, and have an important complementary role to play. 19,29 specialist skills in psychometric test usage, brain-behaviour relations and psychiatric diagnosis, enables them to conduct a differentiated evaluation of an athlete’s post-concussive cognitive, emotional and behavioural status. the ease with which the computer-based test profiles can be transmitted by e-mail greatly facilitates the doctor-psychologist liaison necessary for widespread sports concussion services to occur at the highest professional level in a relatively cost-effective manner. nevertheless, substantial healthrelated funding will be needed to implement optimal concussion management amongst sports populations that are economically disadvantaged, such as pertains to large numbers of individuals in a country such as south africa. acknowledgements research for this review was funded by the national research foundation (nrf) and the rhodes university council. incidence figures are rounded to the nearest decimal point. due to space restrictions citations were kept to a minimum. an alternative version of this article with a comprehensive set of references is available on request from the corresponding author. the authors are commercially involved in the development of neurocognitive screening as a component of sports concussion management in south africa and britain, using the impact programme. references 1. barnes bc, cooper l, kirkendall dt, mcdermott tp, jordan bd, garrett we. concussion history in elite male and female soccer players. am j sports med 1998; 26: 433-8. 2. baroff gs. is heading a soccer ball injurious to brain function? j head trauma rehabil 1998; 13: 45-52. 3. barr wb. neuropsychological testing of high school athletes. arch clin neuropsychol 2003; 18: 91-101. 4. bathgate a, best jp, craig g, jamieson m. a prospective study of injuries to elite australian rugby union players. br j sports med 2002; 36: 265-9. 5. behr m. beyond the grass ceiling. fairlady, october 2001: 49-51. 6. bird yn, waller ae, marshall sw, alsop jc, chalmers dj, gerrard df. the new zealand rugby injury and performance project: v. epidemiology of a season of rugby injury. br j sports med 1998; 32: 319-25. 7. bohnen n, van zutphen w, twijinstra a, wijnen g, bongers j, jolles j. late outcome of mild head injury: results from a controlled postal survey. brain inj 1994; 8: 701-8. 8. cassidy jd, carrol lj, peloso pm, borg j, von holst h. incidence, risk factors and prevention of mild traumatic brain injury: results of the who collaborating centre task force on mild traumatic brain injury. j rehabil med 2004; suppl 43, 28-60. 9. collins mw, grindell sh, lovell mr, et al. relationship between concussion and neuropsychological performance in college football players. jama 1999; 282: 964-70. 10. cremona-meteyard sl, geffen gm. persistent visuospatial attention deficits following mild head injury in australian rules football players. neuropsychologist 1994; 32: 649-62. 11. delaney js, lacroix vj, gagne c, antoniou j. concussions among university football and soccer players: a pilot study. clin sports med 2001; 11: 234-40. 12. ewing r, mccarthy d, gronwall d, wrightson p. persisting effects of minor head injury observable during hypoxic stress. j clin neuropsychol 1980; 2: 147-55. 13. farace e, ferree rm, hollier ja, barth jt, shaffrey me. trails a: neurocognitive effect of previous concussions in woman’s rugby sample (abstract). j int neuropsychol soc 2003; 9: 207. 14. frencham kar, fox am, maybery mt. neuropsychological studies of mild traumaic brain injury: a meta-analytic review of research since 1995. j clin exp neuropsychol 2005; 27: 334-51. 15. gaetz m, goodman d, weinberg h. electrophysiological evidence for the cumulative effects of concussion. brain inj 2000; 14: 1077-88. 16. ganesalingam k, sanson a, anderson v, yeates ko. self-regulation and social and behavioral functioning following childhood traumatic brain injury. j int neuropsychol soc 2006; 12: 609-21. 17. gronwall d, wrightson p. cumulative effect of concussion. lancet 1975; 2: 995-7. 18. guo z, cupples la, kurz a, et al. head injury and the risk of ad in the mirage study. american academy of neurology 2000; 54: 1316-23. 19. guskiewicz km, bruce de, cantu rc, et al. national athletic trainers’ association position statement: management of sport-related concussion. journal of athletic training 2004; 39: 297. 20. guskiewicz km, marshall sw, broglio s, cantu rc, kirkendall dt. no evidence of impaired neurocognitive performance in collegiate soccer players. am j sports med 2002; 30: 157-62. 21. iverson gl, brooks bl, lovell mr, collins mw. no cumulative effects for one or two previous concussions. br j sports med 2006; 40: 72-5. 22. iverson gl, gaetz m, lovell mr, collins mw. cumulative effects of concussion in amateur athletes. brain inj 2004; 18: 433-43. 23. jakoet i, noakes td. a high rate of injury during the 1995 rugby world cup. s afr med j 1998; 88: 45-7. 24. killam c, cautin rl, santucci ac. assessing the enduring residual neuropsychological effects of head trauma in college athletes who participate in contact sports. arch clin neuropsychol 2005; 20: 599-611. 25. kutner kc, erlanger dm, tsai j, jordan bd, relkin nr. lower cognitive performance of older football players possessing apolipoprotein e epsilon 4. neurosurgery 2000; 47: 651-7. 26. lezak md, howieson db, loring dw. neuropsychological assessment. 4th ed. oxford: oxford university press, 2004. 27. lovell mr, collins mw, iverson gl, johnston km, bradley jp. grade 1 or ‘ding’ concussions in high school athletes. j neurosurg 2004; 98: 296301. 28. maddocks dl, saling m, dicker gd. a note on normative data for a test sensitive to concussion in australian rules footballers. australian psychologist 1995; 30: 125-7. 29. makgoke p. media statement by the health professions council of south africa (hpcsa). south african psychiatry review 2004; 7: 39. 30. matser jt, kessels ag, jordan bd, lezak md, troost j. chronic traumatic brain injury in professional soccer players. neurology 1998; 51: 791-6. 31. matser j, kessels ag, lezak md, jordan bd, troost j. neuropsychological impairment in amateur soccer players. jama 1999; 282: 971-3. 32. matser e, kessels a, troost k, lezak m. letter in reply to dr babbs and drs grote and donders. jama 2000; 16: 883. 33. mccrory p. when to retire after concussion? br j sports med 2001; 35: 379-82. 34. moser rs, schatz p, jordan bd. prolonged effects of concussion in high school athletes. neurosurgery 2005; 17: 91-100. 35. nathan m, goedeke r, noakes td. the incidence and nature of rugby pg32-38.indd 37 7/5/07 10:33:43 am 38 sajsm vol 19 no. 2 2007 injuries experienced at one school during the 1982 rugby season. s afr med j 1983; 64: 132-7. 36. price bh, daffner kr, stowe rm. the comportmental learning disabilities of early frontal lobe damage. brain inj 1990; 113: 1383-93. 37. american psychiatric association. diagnostic and statistical manual of mental disorders. 4th ed. text revision (dsm iv-tr). washington, dc.: apa, 2000. 38. putukian m, echemendia rj, mackin s. the acute neuropsychological effects of heading in soccer: a pilot study. clin j sport med 2000; 10: 1049. 39. reitan rm, wolfson d. the two faces of mild head injury. arch clin neuropsychol 1999; 14: 191-202. 40. ruff r. two decades of advances in understanding of mild traumatic brain injury. j head trauma rehabil 2005; 20: 5-18. 41. rutherford a, stephens r, potter d. the neuropsychology of heading and head trauma in association football (soccer): a review. neuropsychol rev 2003; 13: 153-79. 42. south african press association. legal now for women to go boxing. eastern province herald, 24 august 2001: 4. 43. satz p. brain reserve capacity on symptom onset after brain injury: a formulation and review of evidence for threshold theory. neuropsychology 1993; 7: 273-95. 44. seward h, orchard j, hazard h, collinson d. football injuries in australia at the elite level. med j aust 1993; 159: 298-301. 45. shuttleworth-edwards ab, border m, reid i, radloff s. south african rugby union. in: lovell mr, echemendia re, barth jt, collins mw, eds. traumatic brain injury in sports: an international neuropsychological perspective. lisse, the netherlands: swets and zeitlinger, 2004: 149-68. 46. shuttleworth-jordan ab. age and education effects on brain-damaged subjects: negative findings revisited. clin neuropsychol 1997; 11: 205-9. 47. silver jm, yudofsky sc, anderson ke. aggressive disorders. in: silver jm, mcallister tm, yudofsky sc, eds. textbook of traumatic brain injury. washington, dc: american psychiatric publishing, 2005: 259-77. 48. stephens r, rutherford a, potter d, fernie g. neuropsychological impairment as a consequence of football (soccer) play and football heading: a preliminary analysis and report on school students (13-16 years). child neuropsychology 2005; 11: 513-26. 49. wills sm, leathem jm. an investigation of brain injury incurred in new zealand club-grade rugby. j int neuropsychol soc 2001; 7: 405. 50. witol ad, webbe fm. soccer heading frequency predicts neuropsychological deficits. arch clin neuropsychol 2003; 18: 417. pg32-38.indd 38 7/5/07 10:33:44 am 28 sajsm vol 20 no. 1 2008 introduction with increasing interest and emphasis placed on sport, athletes are continually searching for anything that will give them a more competitive edge. next to cycling hardware, the cyclist is most concerned about training schedules. if music were added to training, then training could be perceived as less monotonous and less arduous. thus the inclusion of music into training programmes may result in increased exercise effort, training adherence and a possible positive effect on performance. 2,7,9 previous studies have yielded contradictory findings. most of the preceding work has concentrated on physiological and subjective responses to music, while performing either aerobic or anaerobic exercise. 1,7,8 none of the previous studies has measured the effect of music on a specific athletic group, like cyclists. it is common practice to include background music while exercising, 5 as it lends to the pacing of movement, as well as enhances emotive and distractive elements in the athlete. 9,10 cycling, as both a hobby and a sport, is gaining popularity. in order to become accomplished, cyclists need to spend many hours on a bicycle, whether it is on the road or on an indoor trainer. incorporating music with training will most likely limit boredom and loss of motivation in most cyclists, and help maintain training momentum. the aim of this study was to investigate whether music causes changes in physiological and psychological variables during submaximal cycling. original research article effect of music on submaximal cycling abstract objective. athletes frequently report training to music, yet there have been relatively few studies that have addressed the benefit of exercising with music. design. volunteer men and women (n=30), aged between 18 and 40 years, performed an initial familiarisation session. part of this session involved the measurement of maximal oxygen consumption. with at least a 48-hour intervening period, this was then followed by a first 20-minute submaximal cycling session, at 80% of maximal oxygen consumption. at least 48 hours later a second submaximal cycling session was performed. subjects were randomly divided into two groups. group a cycled without music and group b cycled with music for the first submaximal cycling session. subjects underwent the same testing procedure for the second submaximal cycling session, but this time group a cycled to music and group b cycled without music. subjects served as their own controls. setting. the study was performed in the physiology exercise laboratory, at the university of the witwatersrand. main outcome measures. during the submaximal sessions heart rate, perceived exertion (borg scale) and plasma lactate concentration were assessed. subjects completed a post-test questionnaire once both submaximal cycling sessions were completed. correspondence: nicola schie 2 the grove golders green london nw11 9sh tel: +44 772 566 5320 e-mail: nicola.schie@gmail.com nicola a schie (bsc physiotherapy, msc physiotherapy) 1 aimee stewart (bsc physiotherapy, dpe, msc (medicine), phd)1 pieter becker (phd)2 geoff g rogers (phd)3 1 university of the witwatersrand, faculty of health sciences, school of therapeutic sciences 2 south african medical research council, biostatistical services and training 3 university of the witwatersrand, faculty of health sciences, school of physiology results. there were no significant differences in physio logical variables (change in plasma lactate and heart rate), nor were there any significant differences in borg scale ratings when the subjects cycled with and without music. however, according to the post-test questionnaire 67% of subjects identified the cycling session with music to be easier than the session without music. conclusion. listening to music while performing submaximal cycling resulted in no physiological benefit. yet, the cycling session done in conjunction with music was deemed, by the majority of the subjects, to be easier than the cycling session without music. pg28-31.indd 28 4/23/08 11:33:35 am sajsm vol 20 no. 1 2008 29 methods all procedures used in this study have been approved by the committee for research on human subjects, at the university of the witwatersrand, johannesburg. study design a two-period cross-over design was undertaken (fig. 1). subjects to calculate the sample size, a change on the borg scale was used as the primary efficiency variable. in accordance, a sample of 28 cyclists was shown by a power calculation to provide at least 90% power to detect an experimentally relevant difference between the two groups. a total of 30 cyclists volunteered and provided written consent to participate in this study. subjects were excluded from the study if they had any underlying systemic disease, any contraindication to participating in submaximal exercise, or any acute injury that could interfere with cycling performance. professional cyclists were excluded from this study. general procedures the study was performed in an exercise laboratory. throughout the study the environment within the laboratory remained at room temperature (21 23°c), and an electric fan was used to facilitate sweat evaporation. the laboratory was kept as visually sterile as possible. all subjects participated in an initial familiarisation and measurement of maximal oxygen consumption session, followed by two separate submaximal cycling sessions. the three sessions were planned at least 48 hours apart and each session was scheduled at the same time of the day. all subjects were instructed to refrain from eating or drinking (except for water) for at least 2 hours prior to testing. in addition, subjects were asked not to exercise for 12 hours before the sessions. familiarisation and maximal oxygen consumption session during this session subjects were asked to read and sign informed consent. in addition, they were asked to complete a medical screening 6 and a pretest questionnaire. the medical questionnaire allowed for detection of any past and present medical conditions, as well as to confirm that no undesirable substances had been ingested. the pretest questionnaire obtained an exercise history and biometric data from each subject. after the collection of anthropometric data, maximal oxygen consumption (v02max) was determined using an intermittent, incremental protocol on a cycle ergometer (dynavit meditronic, keiper dynavit company, kaiserlauten, west germany) and a calibrated metabolic cart (oxycon 4, mjinhardt, netherlands) to measure oxygen consumption. the v02max test consisted of a 10-minute warm-up at 100 watts (w), followed by a 5-minute workload of 150 w. for the measurement of v02max starting load varied depending on the subject’s cycling ability. workloads were increased in 20w stages. each load lasted for 3 minutes or until the subject was too exhausted to carry on pedalling, followed by a 10-15-minute rest period. maximal oxygen consumption was taken as the average of the oxygen consumptions measured, when an increment of 20 w resulted in a v02 which differed by less than 1 ml/kg.min from the previous v02 measurement. submaximal cycling sessions for the submaximal cycling sessions the subjects secured their own bicycles onto the cyclosimulator (model: cat-eye, osaka, japan), which was calibrated before the start of the study. a resting, finger-prick lactate concentration measurement was taken, using a hand-held lactate analyser (accusport boehringer mannheim, germany). once on their bicycles, the cd player (discman, sony d-121 mega bass, japan) was linked up to lightweight earphones which were securely placed in the subject’s ears, regardless of whether the cycling session was with or without music. the subjects were allowed to adjust the volume prior to the start of the cycling session. subjects were also linked up to the metabolic cart, via a two-way non-rebreathing valve (hans rudolph inc. kansas city, missouri, usa). the cycling session began with a brief warm-up (2 8 minutes). the warm-up ended once subjects reached 80% of their maximal oxygen consumption. during the 20 minutes of submaximal cycling, subjects were asked to keep within a 78 82% range of their v02max. subjects were allowed to view this information on the oxycon monitor. verbal encouragement was only given when subjects were not maintaining their work intensity range. the first submaximal cycling session was conducted without music for group a and with music for group b. the music used was identical and in the same order for all subjects. five songs, imagine (john lennon), bohemian rhapsody (queen), summer of ’69 (bryan adams), sunday bloody sunday (u2) and how you remind me (nickelback), were randomly selected out of the top ten songs of all time, voted for in a radio poll at the end of 2002. this ensured that the music that was played during the study consisted of varied tempos. the radio station’s audience is of a similar age group to that of the subjects who participated in this study. during the cycling sessions, subjects were blinded as to what their heart rate, distance and speed were. subjects were only conscious of the time and their oxygen consumption. after every 2-minute interval and on completion of the test (starting at time 2 minutes and ending time 20 minutes), heart rate (beats per minute) and borg scale readings were recorded. a polar heart 1 1 st submaximal 2 st submaximal cycling session cycling session group a-no music wash out period group b-no music group b-music group a-music fig. 1. schematic representation of two-period cross-over design.fig. 1. schematic representation of two-period cross-over design. 1 1 st submaximal 2 st submaximal cycling session cycling session group a-no music wash out period group b-no music group b-music group a-music fig. 1. schematic representation of two-period cross-over design. pg28-31.indd 29 4/23/08 11:33:37 am 30 sajsm vol 20 no. 1 2008 rate monitor (model m21; oy, finland) was used to record the subject’s heart rate. instantaneous perception of exertion was measured using the 10-point borg scale 4 distance and time were measured by the cyclosimulator. shortly after the completion of the cycling session, before the cyclists had dismounted from their bicycles, another finger-prick lactate concentration measurement was taken. the identical procedure was followed in the second submaximal cycling session. the second submaximal cycling session took place at least 48 hours after the first session. group a now cycled with music, and group b cycled without music. statistical analysis the difference between ‘with’ and ‘without’ music with respect to heart rate, borg scale and change in plasma lactate concentration were analysed using a 2-way analysis of variance (anova), adjusting for the baseline which was taken to be 2 minutes after the start of exercise. the data were analysed and corrected for both fixed and random effects. differences were accepted as significant at p<0.05. results the physical characteristics (means ± standard deviations) of all the subjects are illustrated in table i. according to the pretest questionnaire, most subjects cycled more than 100 km per week, and the majority cycled, on average, on 3 different occasions during the week. there were no differences between the groups with regard to physical characteristics, training histories and oxygen consumption measured during exercise. there was no significant difference in the change in blood lactate concentration (table ii), heart rate (table iii) and borg scale (table iv) when comparing the cycling session with music to the cycling session without music. the subject’s perception of the cycling sessions, with music and without music, was inconsistent with the objective findings. exercising to music was perceived as being significantly less demanding than exercising without music. the majority of subjects (67%) identified the cycling session with music as the easier of the two cycling sessions, compared with 17% who found cycling without music easier and 17% who rated the sessions the same. most (57%) subjects found the music to be overall stimulating, while 27% indicated that overall the music was relaxing. some (6%) said that they found the music to be both stimulating and relaxing and the last 10% expressed that the music evoked some other sensation. discussion the most interesting finding in this study was the inconsistency between the subjects’ overall perception of the cycling sessions and their instantaneous perceived exertion at 2-minute intervals. even though there were no significant physiological or instantaneous ratings of perceived exertion differences between measurements made at 2-minute intervals during the cycling with or without music, 67% of subjects indicated that the cycling session with music was substantially easier than the session without music. this inconsistency highlights that there must be psychological influences occurring during submaximal exercise. it is possible that the subjects enjoyed the cycling session with music more than without music, and thus they perceived it to be easier. the music may have generated positive emotional states rather than acting purely as a distracter. fifty seven per cent of subjects found the music to be stimulating. this may have contributed to subjects’ finding the cycling session with music to be easier. the music in this study was deliberately made up of varying tempos, so that the tempo of the selected songs would not influence the objectivity of the results. consequently, one would have expected that more subjects would have found the music to be a combination of stimulating and relaxing sounds. analysis of the subjects’ heart rate failed to produce any significant differences. twenty minutes of cycling may not have been enough of an extended physiological strain. the reason why 20 minutes was chosen was because many similar table ii. mean change in plasma lactate concentration (mmol -1 ) before and after cycling at 80% vo2 with and without music (n=30) with music ± sd without music ± sd p-value cod (%) 5.4 ± 2.1 5.8 ± 2.1 0.32 86.3% change in plasma lactate = plasma lactate concentration measured after exercise minus plasma lactate concentration before exercise; sd = standard deviation; cod = coefficient of determination. table i. physical characteristics of subjects (group a and b combined, n=30) mean ± sd age (years) 29.3 ± 5.1 weight (kg) 70.4 ± 10.6 height (cm) 174.3 ± 7.1 vo2max (ml min -1 .kg -1 ) 52.0 ± 8.6 sd = standard deviation. table iii. means for heart rate responses while cycling at 80% vo2max with and without music (baseline adjusted to 2 minutes) (n =30) time with ± sd without ± sd p-value cod (min) music music (%) 4 150.9 ± 8.0 151.0 ± 8.0 1.0 91.0 20 169.7 ± 6.9 167.7 ± 6.9 0.07 92.8 min = minutes; sd = standard deviation; cod = coefficient of determination. table iv. means for rating of perceived exertion (borg scale) while cycling at 80% vo2max with and without music (baseline adjusted to 2 minutes) (n =30) time with ± sd without ± sd p-value cod (min) music music (%) 4 3.4 ± 0.8 3.4 ± 0.8 0.67 80.0 20 4.8 ± 1.0 4.6 ± 1.0 0.32 89.6 min = minutes; sd = standard deviation; cod = coefficient of determination. pg28-31.indd 30 4/23/08 11:33:38 am sajsm vol 20 no. 1 2008 31 studies 3,7,11 utilised this particular time period for their testing and got favourable results. subjects in this study indicated that the music was stimulating, and that may have been the reason why at 20 minutes the average heart rate during the cycling session with music (169.7 beats/min) was slightly higher than the cycling session without music (167.7 beats/min). the heart rate findings in this study are similar to those reported in the following research, 5,7,10 where no significant difference in heart rate was found between the session with music and without music. this study showed that music had no influence on the instantaneous borg scale ratings. the results of this study are in contrast with findings of nethery, 5 potteiger et al. 7 and szabo et al. 10 the latter studies all found that music resulted in a reduced rating of perceived exertion. a possible reason for this contrast may be differences in the subject groups used. our subject group consisted of trained and disciplined cyclists participating in a study using cycling as the mode of exercise. other studies used mostly untrained subject groups or groups of heterogeneous athletes, some of whom were unfamiliar with the mode of exercise used in the study. our cycling sessions only lasted for 20 minutes (excluding the warm-up session). since the borg scale became more pronounced with time, it is likely that had the study period gone on for longer the results might have been different. another possible reason could be that the subjects were working at a relatively high intensity (80% of the vo2max). it is possible that at this intensity the subjects’ physiological cues could overpower distraction stimuli such as music. contrary to szmedra and bacharach, 9 who showed the exercise session with music to have a smaller change in plasma lactate concentration, compared with the exercise session without music, this study showed that there was no significant difference in plasma lactate concentration between the groups. conclusion listening to music while performing submaximal cycling resulted in no physiological benefit. however, it may allow individuals to alter their overall perception of effort while cycling. by acting as a positive emotional distracter, music may motivate the cyclist to increase adherence to training, allowing the to train longer and more efficiently. acknowledgements this research received no external financial assistance. the following people and institutions are acknowledged: nomonde molebatsi for her assistance in the exercise laboratory, and the school of physiology, health science faculty, university of the witwatersrand, for allowing the exercise laboratory to be used and for supporting many of the costs of the study. references 1. atkinson g, wilson d, eubank m. effects of music on work-rate distribution during a cycling time trial. int j sports med 2004; 25: 6115. 2. becker n, brett s, chambliss c et al. mellow and frenetic antecedent music during athletic performance of children, adults and seniors. percept mot skills 1994; 79: 1043-6. 3. boutcher sh, trenske m. the effects of sensory deprivation and music on perceived exertion and affect during exercise. journal of sport and exercise psychology 1990; 12: 167-76. 4. grant s, aitchison t, henderson e, et al. a comparison of the reproducibility and the sensitivity to change of visual analogue scales, borg scales, and likert scales in normal subjects during submaximal exercise. chest 1999; 116: 120817. 5. nethery vm. competition between internal and external sources of information during exercise: influence on rpe and the impact of the exercise load. j sports med phys fitness 2002; 42: 172-18. 6. pate rr, blair sn, durstine jl. guidelines for exercise testing and prescription, 4th ed. philadelphia and london: lea & febiger, 1991. 7. potteiger ja, schroeder jm, goff kl. influence of music on ratings of perceived exertion during 20 minutes of moderate intensity exercise. percept mot skills 2000, 91: 848-54. 8. pujol tj, langenfeld me. influence of music on wingate anaerobic test performance. percept mot skills 1999; 88: 292-6. 9. szmedra l, bacharach dw. effect of music on perceived exertion, plasma lactate, norepinephrine and cardiovascular hemodynamics during treadmill running. int j sports med 1998; 19: 32-7. 10. szabo a, small a, leigh m. the effects of slow-and fast-rhythm classical music on progressive cycling to voluntary physical exhaustion. j sports med phys fitness 1999; 39: 220-5. 11. white vb, potteiger ja. comparison of passive sensory stimulations on rpe during moderate intensity exercise. percept mot skills 1996; 82: 819-25. pg28-31.indd 31 4/23/08 11:33:38 am j o u r n a l o f t h e s a s p o r t s m e d i c i n e a s s o c i a t i o n t y d s k r i f • kaffei'en in urine •soccer injuries cont • gesondheidsbevordering • rastioneel-emotiewe terapie vol 2 no 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) reg. tlo./nr. tv5. in sports injury and trauma. ® didophen c lin ic a lly w e ll to le ra te d ttiflim m tndl— m l ■**•01.100 voltaren gt 50 geigy 'coated tablets) lots tre a te d worldwide* •statistics on file r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) contents w m editorial comment alternative medicine w m pensees herewith the baton feature soccer injuries cont. w m ultra man ultra man faces intense competition e l glansartikel die plek van oefening in gesondheidsbevordering |£1 glansartikel konsentrasies van kaffei’en in urine f s glansartikel rasioneel-emotieweterapievirsportlui m£ a s a s m a u p d a t e sasma news |£j rugbynews prevention of rugby injuries ed physiotherapy column basic conditioning for rugby editor in chief dr c noble mbbch.fcs(sa) associate editors proftnoakesmbchb.md dr daw ie van velden mb chb (stell), m prax med(pretoria) advisory board medicine: dr i cohen mb chb d obst, rcoc orthopaedic traumatology: dr p firer bsc (eng) mb bch (wits) m med (orthoxwits) bric e hugo mb chb, mmed (chir) orthopaedics dr jc usdin mb bch, frcs (edin) cardiology: col dp myburgh sm mb chb, facc physical education: hannes botha d phil (phys ed) gynaecology: dr jack adno mb bch (wits) md (med) dip o&g (wits) front coven transparency courtesy o f colour library. the journal o f the sa sports medicine association is exclusively sponsored by ciba-geigy (pty) ltd. the journal is produced by commedica po box 3909, randburg 2125. the views expressed in this publication are those of the authors and not necessarily those of the sponsors or publishers. ^ p o rtb e s e rio g s s *1 | s p o rt in ju ry an d • w f io r b h a w it a s ie c a rd ia c r eh ab dita bo n p rcxyam p ro g ra m m e journal of the sa _ sports medicine tydskr/f van dies a sportoeneeskundeverenioino 11-13 18-20 ciba-geigy r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) alternative medicine: clive noble, mbchb. fcs (sa) editor in chief. editorial board meeting as regards running injuries it can safe­ ly be said that most of these will get better themselves. most of the time this will be within a few days of the on­ set of injury, but may take weeks or even months. usually there is a reduc­ tion of activity as a protection of the part due to pain which allows healing to take place. in my own practice many cases who had to wait for an appoint­ ment for a few weeks, phone to say that the problem got better while they were waiting for the appointment. whoever happens to be treating the patient at the time he is recovering spontaneously, will claim the cure no matter how unscientific the treatment has been. reflexology, homeopathy, naturopathy, chiropractic and a host of other modes of alternate medicine all claim out­ standing results in sports injuries. acupuncture has long been used in treating sportsmen including provincial rugby players. only with a careful clini­ cal trial will we ever be able to evalu­ ate alternate medicine as a form of treatment. dr "ponky" firer has donated a prize of r500 for the best original article pub­ lished in this journal each year. we thank him for his generosity. her friend, went to see ronald holder who describes himself as a kinesthisiologist. he apparently diagnosed her problem as a muscle imbalance and proceeded their shoes which would surely aggravate the bio­ mechanical problem, but have nevertheless been successful. has his success been due to the fact that most of these cases would have got better by themselves, as on recent investigation into injuries in­ curred in the training for a british marathon would suppose? has it been a placebo effect? the answers to these questions may equally apply to all forms of alternate medicine or even sometimes to “scien­ tific" medicine itself. a meeting of the sponsors, ciba-geigy, the publishers, commedica; and mem­ bers of the editorial board o f this jourj nal was recently held in johannesburg. at this meeting it was decided to have a physiotherapy column as well as a nutrition column which should be of great interest to our readers another innovation will be a philosophy column | a la ceorge sheehan which should also be most enjoyable. it was decided that both scientific articles as well as p ra c tic a l, easily understood articles will also be used. this is in keeping with the previous format. if you, the reader, have any suggestions we will welcome them. our aim is to increase knowledge in s p o rts medicine. ^ december 1987 v o l 2, no 4,19* ecently zola budd sus­ tained a running injury which threatened her career she received treatment from a variety of sports physicians in­ cluding laser and injec­ tion therapy from a german clinic, but all to no avail. she finally returned to south africa where she consulted more doctors, but still with no improvement. finally, on advice of to make a support from the "yellow pages" which is held together with tape and inserted into her running shoe. almost immediately she was rendered pain-free and was able to recommence her running career. was this a miracle; was it just a fluke, or was it a scientifi­ cally accurate assessment of her mus­ cle imbalance corrected by a (usually) 2-3mm thickness of "yellow pages" placed in her shoe7 i have seen many of his successes, but also many of his failures so i think it is extremely difficult to answer the question, strongly doubt his scientific credibi­ lity many of his cases (if not all) are told they have a leg length dis­ crepancy. a number of these cases have had scientifically accurate radiological leg length measurements that revealed equal leg lengths. other cases have had sup­ ports put in r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) herewith the baton/ # have pleasant memories of some of the restaur­ ants that i have had the good fortune to visit over the last two decades. as a visual experience still burnt into an unaffected part of my brain none surpasses the one at high wycombe in england. there, in the late afternoon summer sun, was the archetypal english scene, trees with lush foliage, spontaneously combusting into all the imaginable shades of green. the village-green itself dotted with cricketers, and a very old, very english pub. it sported a proprie­ tor who delighted in walking you through the kitchen to show the sim­ mering menu, allowing you to savour each delicate aroma. then there was the restaurant in dur­ ban that out-colonized anything the colonies even in their heyday could chris klopper "i came across the rather pleasant, somewhat sparsely distributed, tradition of consuming the merest hint of vanilla sorbet to clear the palate before the arrival o f the next course." readable scientific fare packaged in that special ambience that only sport can provide. what then, do you ask, clears the palate between the heavy numbers on the academic menu? renewed readiness for more action. here is a man (also a father, a physician, runner/pot hunter, a cyclist, an excel­ lent speaker and a columinist of sta­ ture) who when speaking to an au­ dience of research chemists about the problems of research and the eureka experience, captured the nett worth of every drop o f perspiration that i had ever shed. "play' he said, "is the problem solv­ er. running — or any of the other exercises i proposed — is a celebra­ tion of the body and a holiday for the soul.” (here the sorbet becomes the main course.) this column, by way of contributions that will be made by those not content to blindly practice sportsmedicine but to reflect upon its implicit paradigms meditatively, is unreservedly inspired by george sheehan's running wild. this is one marathon though, in which a . offer as an alternative here for the tlme 1 came across the rather pleasant, somewhat sparsely distribut­ ee, tradition of consuming the merest b t l ^ anil,a sorbet to clear th e pa before the arrival of the next course, already hovering in the wings, ^ m a n y w a ^ this journal strains awards offering the same experiences i 1987 vol 2, no 4,1987 george sheehan m.d in his regular column running wild, which appears monthly in the physician and sports medicine does for sportsmedicine jour­ nalism what vanilla sorbet does for the most carefully crafted cuisine.a mo­ ment of freshness, the sheer delight of which explodes against the overworked 'taste buds', surprising them into he will probably remain for the most part far out in front; but then, as in marathons, to use his words again "we will never discover the truth second­ hand." he went on to say; if l am to write the truth, or know it when i read it, i must first live it. let these contri­ butions be our living truth. herewith the baton. ^ r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) continued from vol 2 no 3 soccer injuries i. surve 4th year medical student, j. ranchod 4th year medical student, a n kettles registrar from: the department of community health, university of cape town. ield conditions f aii fields on which matches were played were graded according to a checklist with a maxi­ mum score of 40. the number of injuries and of player hours for each field was deter­ mined, and the injury incidence per 1000 hours was calculated. it would be expected that higher field grading scores would correlate nega­ tively with injury incidence however an anomaly arose with field a, which is the best field. on this field most of the pre­ mier division matches were played. it was in this division that most injuries occurred. if field a is excluded in cal­ culating correlation, the correlation coefficient r = 0,84 (p< 0,01). if field a is included, then r = 0,31. although it may be concluded that quality of fields determine to some extent the risk of injuries, other factors may override such influence. weather conditions did not appear to influence the incidence of injuries markedly; 93% occurred dur­ ing sunshine and 71% on dry fields. injuries related to referee grading the number of matches controlled by each grade of referee, and the number of injuries sustained in these matches is shown in table vi. table v: relationship of injuries to field grading grade games played player hours no. of injuries incidence injuries per 1000 player hours total r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table vi: number of matches controlled per graded referee and the injuries sustained. number number injuries o f of per grade matches injuries match ” 1 54 35 (48%) 0,65 2 95 5 (7%) 0,05 3 78 33 (45%) 0,42 considering the fact that 54 (24%) matches played by the premier and 1st division ac­ counted for 35 (48%) of all the injuries and that these “2* matches were led by top grade referees, it would •, appear that the grade of s referee has no material in­ fluence on the occurrence of injuries as determined by other variables most matches (95 or 42%) were controlled by grade 2 referees there were only 5 (7%) injuries in these matches, at a rate of 1 injury per 20 matches. 300 injuries per 1000 game hours, 16,9 inw juries per 1000 player hours.1 however, / j ekstrand defined ■ v j ^ injury differently as "an injury a causing a player ' to miss the next game", not: "having to i leave the field". the results from the studies of bass; v muckel8 and weightman > \ browne9 show an incidence i \ of h 30, and 3,6 per 1000 game hours re 7 ’ spectively. renstrom \ and peterson10 re^ ported an incidence of 1 injury in every 23 games, or about 200 per 1000 game hours. different defini­ tions for injury make com­ parison of these results ex­ tremely difficult. the premier division repre­ sents the highest level of i competition in this study, this division also recorded / k the highest incidence of ( injury (27 per 1000 man hours played), which cor­ responds to data reported \ from other studies in fin\ land5 and norway'1 peter­ son and renstrom,10 how­ ever, found no difference i in the incidence of injury \ between the players in \ different divisions in . \ their study in sweden. 3 < the low 'nciclence r . injuries in the 2nd division (2,2 injuries per i 1000 man hours) may j reflect a lower level of f competitiveness in this / division; although other factors may also play a ; role in this low incidence. types of injury the commonest type of injury is sprains (42% which is consistent with other studies. 3:12 however, the number of fractures recor­ ded is much lower than that in other studies.'” ’-'' the high number o f sprains in the forward and midfield posi­ tions could be due to the skil­ ful dribbling involved in these positions, especially since 16 of the 22 sprains recorded were ankle sprains anatomical site of injury lower limb injuries were found to be the commonest accounting for 74% of all injuries. wilkinson/ ekstrand,1-12 sandelin5 and mach lum et al2 confirm this in their studies. in their studies ankle and knee injuries were the commonest of all lower limb injuries, in this study ankle injuries are the com­ monest. j protective equipment , none of the players with shin ^ lacerations (12% of all injuries) were wearing shinguards. ) ekstrand12 found 50% of lacera f tions occurring in those players i not wearing shinguards.12 it is in i teresting to note (since we do not know the total number of players wearing shinguards) that all shin lacerations and ankle injuries occur i red in players not wearing shini guards and ankle taping respectively condition of field j the results show a significant cor­ relation between lower grading of fields and higher incidence of injuries. this is only so if the premier division matches played on the top graded a field are excluded. these showed the highest injury incidence rate, which may be ascribed to con­ founding variables rather than to the good condition of the field. the lowest incidence of injury oc­ curred on the i field (high grade 26). most games played on this field were second division y " ft^artres, a division with a low ^^•^tncidence of injury. the impor­ tance of field quality or surface has been emphasized by wilkinson4 and muckel8 in their studies amongst english soccer players. sandelin in fin­ land, however, found that the field sur­ face did not influence the injury fre­ quency or pattern.5 our data does not permit to separate decisively the pos­ playing position sandelin5 and ekstrand1 have shown in their studies in finland and sweden re, j spectively that playing pom m sition did not correlate j t with any difference in the distribution of injuries. in / this study, if no correction l for position is made, the data are similar to the above studies. however, if the data are corrected, for "number at risk" there is a higher incidence of in­ jury involving the goalkeeper (37% compared to 15%). this could be partly due to the intensity of 1987 vol 2, no 4,1987 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sible determining influence of division from that of quality (grading) of the field. player's opinions the opinion of players was at variance with the objective results of the study in some respects. players thought that fields are the most important factor in causing injuries — this is supported in this study by the strong negative correlation between injury incidence and grading of fields if field a is exclud­ ed. however, unfitness o f players was ranked second by 65% of the players. this contrasts sharply with our finding that 90% of injured players considered themselves fit. the role of the referee featured high among players but this was not confirmed by the study. the absence of shinguards and the calibre of the opposing team were found to be important in this study, and were considered so by players. level of divi­ sion, although featuring prominently in our study was not considered to be im­ portant by most players. recommendations a fundamental problem associated with an epidemiological assessment of data concerning sports related injuries is that of defining criteria and compar­ ing data.1 although this study could not prove decisively what the main causative factors are the authors would like to suggest that the follow­ ing factors would improve the preven­ tion of injury: 1. improved field conditions. 2 good discipline and refereeing apply­ ing especially to the more competitive divisions (including stringent applica­ tion of the rules protecting goalkeep­ ers from injury). 3. consistent use of shock absorbing shin guards. 4. the use of ankle taping. 5. adequate training and warm-up programmes. finally, it is recommended that a more intensive study, possibly including the value of prophylactic measures, be done to determine the importance of such measures in injury prevention. acknowledgements this study was undertaken as a stu­ dent project for the community health (4th year) course under the su­ pervision of dr a. kettles (registrar) as co-author. the statistical advice from mr r. sayed and help from ms n. ka mies, occupational therapist, is grate­ fully acknowledged. the study would not have been possible without the co­ operation of the cape district football association, players and first aiders we are also grateful to dr t.d. noakes for his assistance in editing our project report and to dr j. t. mets for finalis­ ing the manuscript. references 1 ekstrand j, gillquist j-. soccer injuries and their mechanisms, a prospective study. medicine and science in sport and exercise 1983 15 267-270 2 machlum s, daljord 0 a football injuries in oslo a one-year study. british journal o f sports medi­ cine 1984,; 18 186-190. 3. sandelin j.. santavista s., kiviluoto 0: acute soc­ cer injuries in finland in 1980. british journal o f sports medicine 1985; 19 30-33. 4 wilkinson, w.h.c a practical v i e w o f soccer inju ries. british journal o f sports medicine 1978, 12 : 43-45. . . 5. ekstrand j. et al: incidence of soccer injuries and their relation to training and team success. am eri­ can jou rn a l o f sports medicine 1983:11 : 63-67. 6 human science research council ihsr.c.) sports report on south african sports. 1984-1985. 7. bass al-. injuries of leg in football and ballet proceedings o f the royal society o f medicine 1967, 60 . 527-530. 8.muckle dsinjuries in professional footballers british jo u rn a l o f sports medicine 77-78 1981 vol 15 . . . , „ 9. weightm an d, browne r.o injuries in association and rugby football. british jo u rn a l o f sports medi­ cine 1974; 8 183-187. 10. renstrom p., peterson l. fotbollskadot fotboii splan med konstgras valhalla idrottsplots i gote borg rapport naturvardsverkte snvpm 846. 11. roaas a., nilsson s.: major injuries in norwegian football. british journal o f sports medicine 1979, 13 : 3-5 12. ekstrand j, cillauist jthe frequency of mus­ cle tightness and injuries in soccer players. the american journal o f sports medicine 1982, 10i 7578 december 1987 vol2, no 4 ,1 # r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ph o to g r ap h -s as po r ts il lu st r at ed r ultra manir ultra men face intense competition. lain b a n n e r— sports international ental toughness will be just as important as phy |j h * i sical strength and endur i i / i ance when ultra man en l h l j i trants tackle the two months of intense com ^ petition, starting with the duzi canoe marathon from january 28-30. they have already completed the 50km jse marathon, an optional event, and the first of the compulsory events is the 165km vasbyt cycle challenge on november 28. but the hansa duzi, also compulsory, heralds the most gruelling phase of the endurance series backed by the pharmaceutical division of ciba-geigy. after the canoe marathon comes the optional midmar mile swim on febru­ ary 14 — points for all events are worked out according to a special for­ mula, with the first ultra man finisher being awarded 100 and the tough 160km sunday times/leppin iron man triathlon is on february 27. that's another of the four compulso­ ry events, along with the comrades marathon on may 31, but the athlete who wins the ultra man will probably have completed all eight events be­ cause the bonus points available in the optional events are too valuable to pass up. and if that's the case, many of the top ultra man contenders will be riding the argus cycle tour on march 5 — just seven days after the iron man. the optional two oceans marathon on april 2 is next, with the comrades marathon the final, punishing test in the most difficult test of endurance yet devised in south africa. while su­ perb physical condition will be essen­ tial, top triathlete george janos be­ lieves the correct mental approach is just as important. "with so much hard racing in such a short period, one of the most difficult things will be to keep replenishing men­ tal energy;' says janos, who was fourth behind henk watermeyer, richard hol­ liday and nigel reynolds in the 1987 iron man triathlon. "anyone going seri­ ously for a top 10 overall placing will have to avoid a mental blow-out' janos will do all eight events and thinks many of the top contenders will do the same "i want to win ultra man and that me­ ans i need all the points i can get," he says. an industrial engineer, janos had to go back to the drawing board to re-think his training and racing schedule when he realised just how much racing was crammed into such a short period. "i've got to establish a training base this year because there will not be time to train in february and march," he says. “there's no time then to build a base. instead, it will be a case o f sharpening up for each event." doing most of his hard work this year means janos will miss most of the 1987 triathlons they do not fit into his training schedule and he does not be­ lieve he can "do everything". "you have to be realistic," he says. "it's essential to build a solid base from which to compete next year and l,m hoping to do enough to enable me to take a bit of a break in december. like many of the ultra man contenders, janos is hoping for a full river in the hansa duzi. "the more paddling the better" he says "less portage means we can save our legs for the iron man." entries for the ultra man closed on oc­ tober 31 and organisers sports interna­ tional expect a final field of more than 400. top of the ultra man table after one optional event is comrades specialist nick bester, who takes 100 bonus points into the vasbyt challenge after finishing ninth in the jse marathon, lain banner. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) c iba-geigy sponsor first black ultra man entrantthe ultraman, sponsored ___________by ciba-geigy's pharma­ ceutical division, has received its first black entrant, robert lambetha. robert, a plumber from grey's hospi­ tal in pietermaritzburg is an ex­ perienced duzi canoeist, having com­ pleted the event four times, as well as being a strong comrades runner today, ciba-geigy's ken richards con­ tinued his company's sponsorship of lambetha by handing over a new ca­ noe, paddle and bicycle to him in pinetown. in attendance was graeme pope-ellis who believes lambetha has the ability to be most competitive in the ultra man. "with his new equipment, robert will be in a position to prepare fully for the various events forming part of the ultra man" said pope-ellis. lain banner, director of event organiser sports international, believes lam betha's entry will pave the way for an awakening of latent triathlontalent that must currently exist amongst black athletes. "although the logistics attached to pad­ dling pose a problem to competitors who are without transport, ciba-geigy are making an effort to promote the sport by supporting the likes of lam­ betha" said banner ken richards of ciba-geigy believes that guidelines for training in cycling, run­ ning, swimming and canoeing, which his company will prepare over the next few months, will assist all interested sportsmen and women with training techniques and preparation for parti­ cipation in those various sports disci­ plines the ultra man which is made up of four compulsory events, (the vasbyt ultra man cycle challenge, hanza duzi, sunday times/leppin iron man and comrades, and four optional events, js.e„ midmar mile, argus cycle tour and two oceans) is based on an accumula­ tive point ranking system with over r30 000 in prize money on offer to competitors. close on 400 competitors have entered the competition, including the likes of graeme pope-ellis, eddie king, danny biggs, henk watermeyer and piet mare. for fu rth e r inform ation contact michelle or tracey at sport internation­ al on (011) 883-3333. vasbyt 165 km cycle race comrades marathon gold medallist nic bester maintains a narrow lead in the ultra man stakes, despite finishing two minutes down on the leading bunch in the vasbyt 165 km tour in the northern transvaal last week. bester, by virtue of his ninth position in the jse 50 km road race in august, went into the first compulsory ultra man event last saturday with a lead of 100% in the ultra man ratings. but he almost saw his lead in the competition dwindle away on the wind­ swept country road outside pretoria when fellow-pretoria tri-athlete piet mare and natal's keith elleker got away in an 18 man break after 120 km of hard riding. the pair managed to stay with the leading bunch and mare managed to edge ahead of elleker at the line to close the gap on bester in the ultra man ratings. mare held 2nd place to bester going into the vasbyt tour with 92,38% after finishing 2nd ultra man in the jse and the win last weekend means that he has closed to within 5% of besters lead going into the next compulsory event, the hansa duzi canoe marathon towards the end of january. the race was won by natal springbok cyclist peter tomkins in 4 hrs 14 mins. unfortunately not all the results of the vasbyt 165 km cycle race were available at time of going to press hence the omission of an updated ultra man listing. looking down the track as ultra-athletes look ahead the adrenalin will start pumping as they contemplate the jam-packed schedule which awaits them from the end of january. the compulsory duzi from january 28-30 will take its toll, but to build points, competitors will be diving into the midmar mile only fourteen days later just two more weeks to the toughest trial of all — the iron man tri­ athlon on february 27th. director of sports international, lain! banner, believes that competition w ill be such, that leading athletes will not! pass up any chance of building points,! this means that just seven days after! iron man, contenders will be riding the! optional argus cycle tour on march| 5th. phew! what a punishing schedule, but! the r30 000 in prizes, the prestige and! the ultra man medals will make it al| worthwhile, ^ december 1987 vo l 2, no 4,1987 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) die plek van oefening in gesondheidsbevordering f. p. retief m.b. ch.b., m.r.c.p., m.d., d. phil. oxford. direkteur-generaal, departement van nasionale gesondheid en bevoikingsontwikkeling he role o f exercise in the promotion o f health the im portant m otto mens sana in corpore sano reminds us that a healthy mind and body is the ideal ar­ mour with which to tackle life too many south africans, however believe that a healthy mind can be cultivated through mere passive recreation com­ petitive participation is not a prereq­ uisite for the cultivation o f a healthy mind. a cheerful mind and healthy lifestyle have become an urgent neces­ sity, given the significant percentage o f our total disease load ascribable to a disease promoting lifestyle given an ever ageing popula­ tion, exercise should be in­ creasingly emphasised as a brake to the physio­ logical processes o f ageing. south africans from all parts o f the population spectrum seem unable to revert to a lifestyle o f in­ creased activity — be it due to work pressure o r life stressors such as ur­ banisation and poverty. concerted community e ffo rt can play an important role to help involve more people in physical activity programmes m significant example is the north s !e [a-psoject' 5tarted in 1972 in fini e l key elements o f a national wealth programme are: 1) greater clar ^ l reaardin9 psycho-social factors curving physical activity, 2) the applica­ tion o f the behavioural sciences in reaching particular communities, 3) the planning o f fitness awareness pro­ grammes in co-operation with the me­ dia. in south africa the national health plan was announced in 1986. however, it is imperative for each community to work o ut its own health plan. commu­ nity health centres, provided for in the national health plan can act as living laboratories from which to co-ordinate health promoting, activities. health promotion amongst the dit ook so dat die gejaag na prestasie wat so 'n kenmerk van ons alle daagse enjoys special attention with the department, in order to be o f value, youth programmes must, however, be continued into the adult years. mens sana in corpore sano word van een geslag na 'n ander ges lag oorgedra om ons daaraan te bly herinner dat 'n gesonde gees en 'n ge sonde liggaam die ideale wapen toerusting is om die lewe mee aan te durf die lewe se gewone, maar ook meer bedreigende lewensituasies en selfs krisisse, kan daarmee die hoof ge bied word — binne in die lewensterrein van die individu, die geografiese en sosiologiese begrensinge van gemeen skappe en in die besonder ons baie in teressante suid-afrikaanse samelewing. ongelukkig is te veel suid-afrikaners die gedagte toegedaan dat 'n gesonde gees bloot met die hulp van passiewe reaksie gekweek kan word. ons is, toegegee, toeskouers op wie daar staatgemaak kan word! ongelukkig is m e m b e r 1987 v o l 2, n o 4,1987 bestaan is, wel n kenmerk van ons toeskouer deelname is. dan wonder die mens ook nog hoekom hy so moeg en vaal voel na n hele middag se opwinding voor die kassie! verniel ons nie dalk ons koronere vate meer deur so te kyk as deur self te doen en mee te ding nie? is so 'n sater dag dan nie meer stres-belaai as die meeste ander dae van ons lewens nie7 mededingende deelname is natuurlik nie 'n voorvereiste vir die kweek van 'n gesonde gees nie en daarvan getuig dan ook aktiwiteite soos stap, voetslaan, draf en swem — alles dinge wat jy op jou eie kan doen. 'n gesonde gees is in baie opsigte sinoniem met 'n blymoedige gees en is dit nie iets wat ons suid-afrikaners meer naarstigtelik moet nastref nie7 wat het van lag en blote goedigheid geword? idealerwys behoort daar eintlik nie 'n verskil tussen 'n gesonde gees en 'n gesonde leefwyse te wees nie. laasge noemde het 'n dringende noodsaaklik heid geword, gesien die stewige persen tasie van ons totale siektelas wat direk en indirek aan 'n siektebevorderende lewenstyl gewyt moet word. weliswaar toon epidemiologiese studies dat min stens 50% van die mortaliteit van die tien leidende doodsoorsake, na gesond heidsbedreigende gedrag gevoer kan r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) word. weerstand teen oefening en onaktiwiteit is maar te dikwels belan grike elemente van hierdie soort gedrag. lui om te rek, te trek, te werk en te lui om flink te dink! 'n steeds ouerwordende mensdom voorts het ons ook te make met 'n mensdom wat al ouer word en vandag word al hoe meer waarde geheg aan oefening om die prosesse van veroudering te rem. die bekende fisioloog, a j. meyer, het baie indrin gend na hierdie aangeleentheid gekyk. hy stel dit dat die klok van biologiese veroudering nie noodwendig met die biologiese ouderdom van die individu gesinchroniseer is nie hy stem saam met ander kenners dat die groot water skeiding in n mens se lewenspan op die ouderdom 30 jaar plaasvind. weliswaar bereik die mens reeds maksimale gesig en gehoorskerpte op 10 jaar, maksimale weerstand teen infeksies op 15 jaar, maksimale intellektuele vermoe op 21 jaar en maksimale spierkrag op 25 jaar. ns die ouderdom van 30 jaar verwelk die fisiologiese reserwes van die ver skillende organe en stelsels baie lang saam, maar onafwendbaar. fisiologies word veral groot waarde geheg aan veranderinge in die bindweefsel en in die besonder word gewys op die toe name in getal en deursnit van kol lageenvesels wat tot gevolg het dat meer meganiese krag nodig word om hulle te rek of om hulle vorm te her win. met veroudering is daar verlies van spiermassa weens 'n afname in die ge­ tal en grootte van die spierweefsels, te same met 'n verlies van sarkomere en 'n absolute daling in die atp-inhoud van die spiervesels op ouderdom 80-jaar is die spiermassa 30% minder as op 30 jaar. finaliteit oor die oorsake van bover melde verouderingsprosesse ontbreek nog grotendeels, maar metaboliese prosesse gepaard met ophoping van afvalstowwe figureer hier sterk. en daarmee saam gaan vermeerderde kol lageenproduksie vanwee fisiese en moontlik selfs psigiese spanning. dit al les lei tot slytasie en die vraag onstaan dus, hoekom daar nie meer staat ge maak word op vermeerderde fisiese ak tiwiteit, om deur middel van n gesonde leefwyse hierdie prosesse van verou­ dering te rem nie. suid-afrikaners se onmag om 'n gesonder lewenstyl te beoefen ongelukkig bemerk ons daagliks in welke onmag suid-afrikaners verkeer om gehoor te gee aan die oproep om 'n meer gesonde lewens-styl te be oefen, en om in die besonder, groter fisiese aktiwiteit na te streef. in ons samelewing tre f ons by die een pool aan diegene wat welvarend en ontwik keld is maar wat in 'n drukwerkte vas gevang is wat net nie tyd laat vir ont spanning en oefening nie so oorweldig is hierdie persone dat hulle maar later net moet beken: “ek het daar geen be hae meer in nie." dan weer aan die an derkant van die spektrum, hulle wat blootgestel is aan ander soort lewe stressors wat veroorsaak of vererger word deur toenemende verstedeliking of migrasie, industrialisasie, werkloos heid en armoede. die rol van georganiseerde gemeen skapsoptrede begryplik kan wetgewing, kommissies van ondersoek, spesiale owerheidsin stellings en dergelike masjienerie aan hierdie situasie weinig doen. gemeen skappe kan egter verbasend suksesvol optree deur sterk en eendragtig 'n al gemene probleem te identifiseer en dit dan gemeenskaplik aan te pak. daar bestaan natuurlik talle voorbeelde hi ervan. een van die treffendste is waar skynlik die noord karelia-projek wat in 1972 in finland begin is nadat 'n gemeenskap by wyse van 'n massapeti sie vir optrede n aksie, teen hartvaat siektes geloods het. 'n program wat wereldaandag getrek het, is van stapel gestuur, veral gerig op uitskakeling van lewenstyl foute, (onder andere onfiks heid) wat as risiko-faktore vir miokard infarksie geidentifiseer is. hierdie pro jek het veral ook getoon hoe belangrik dit is om kinders vroeg te betrek. hon derde spesiaal-gekeurde werkers is uit gestuur om 'n bepaalde gesondheids boodskap te verkondig en sigbare resul tate het nie lank uitgebly nie. die ou stelling is waar bewys."the people stand up, the doctor steps down". die betrokkenheid van gemeenskappe in bevorderingsprogramme is nie iets nuut nie winslow, 'n grondlegger van gemeenskapsgesondheid, se oor spronklike definisie (soos mettertyd aangepas), verwys na hierdie omvat tende aksie wat onder andere ten doel het "promoting mental and physical health and efficiency through or­ ganised community efforts..." december 1987 vo l 2, 10 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) die sleutelelemente van 'n n a s io n a l e p r o g r a m ■n nasionale program ter bevordering van fisiese aktiwiteit sal na sekere sleu telelemente moet omsien,♦ groter duidelikheid oor die psigo sosiale faktore wat verhinder dat ak­ tiwiteit 'n groter deel van die mens se gesondheidsgedrag uitmaak. w w v u l z , in u • hoe die gedragswetenskappe meer doelgerig ingespan kan word om bepaalde gegewe gemeenskappe te be reik. • hoe om saam met die media strate gee te beplan ten einde gemeenskappe meer fiksheidsbewus te maak. tereg het dr robert butler, 'n voor malige direkteur van die united states national institute on ageing, by geleentheid gese dat "if exercise could be packed into a pill, it would be the single most widely prescribed, and beneficial, medicine in the nation." die nasionale gesondheidsplan cedurende 1986 is die nasionale gesondheidsplan afgekondig en nou wag ons vir gemeenskappe om gebruik te maak van aanbevelinge in hierdie plan ten opsigte van plaaslike betrok kenheid en deelname dit is goed om te beplan vir dit wat op nasionale vlak moet gebeur, maar sekerlik van baie groter belang om te verseker dat elke gemeenskap in suid-afrika sy e/e gesondheidsplan uitwerk en deurvoer. teen relatief lae koste versprei die gedagte van buurtwagte om mense en hul eiendom te beskerm, tans soos 'n veldbrand. kan ons nie op dergelike wyse ook begin dink aan "buur toefeninggroepe" om ons mense se gesondheid te help beskerm en te bevorder nie? gemeenskapgesondheidsentra waar voor daar in die nasionale gesondheids­ plan spesifiek voorsiening gemaak word, is nie net bedoel as plekke vir die behandeling of nabehandeling van pa siente wat nie hospitalisasie benodig nie. dit is inderdaad die ideale plek om baie van 'n gemeenskap se gesond heidsbevorderende aktiwiteite te sen treer — en dit dan ook te doen deur dit tot diep in die gemeenskap uit te dra. dit behoort sentra van omvat tende gesondheidsorg te word en te dien as lewende taboratoria waar programme vir die gemeenskap uit getoets kan word. 'n paar jaar gelede was daar reeds in 'n land soos swede honderde gesondheid sentra in werking, en is liggaamlike opleiding" dan ook as een van die be langrikste aktiwiteite gesien waardeur vervroegde veroudering teengewerk kon word. vanselfsprekend is oefenkun diges en ontspanningbeamptes lede van die multidissiplinere spanne wat by sulke sentra optree. gesondheidsbevordering onder die jeug my departement sowel as ander gesondheidsowerhede bestee reeds op verskeie vlakke tyd en aandag aan gesondheidsbevordering onder die jeug van ons land. die advieskomitee in­ sake gesondheidsopvoeding beywer horn vir gekoordineerde gesondheidsvoorligting in skole deur die onderskeie onderwysowerhede. vanuit hierdie komitee het 'n paaronderwysgidse vir die gebruik van onderwysers in skole reeds die lig gesien, waaronder byvoor beeld: "noodbehandeling van sport bese rings". die bevolkingsontwikkelingsprogram het intussen ook goed op dreef gekom en onderwysen jeugorganisasies tel onder hierdie program se telkengroepe die mikpunt van die program is verhoogde lewenskwaliteit en veral by die jeug moet fisiese aktiwiteit gesien word as een van die steunpilare om juis dit te bereik. vanselfsprekend moet so 'n doelgerigte program natuurlik tot in die volwasse jare deurgetrek word. dit word gese "my departement sowelasander gesondheids­ owerhede bestee reeds op verskeie vlakke tyd en aandag aan gesondheids­ bevordering onder die jeug van ons land:' 1987 dat die fisiese aktiwiteite van mans af neem namate hulle verantwoordelik hede in die aktiewe lewe toeneem. na die huwelik word dit minder, na die eerste kind nog minder — en prof. brink het geoordeel dat nie meer as 10% van ons suid-afrikaanse mans tyd vir fisiese ontspanningsaktiwiteite in ruim nie die gevolgtrekking moet dus gemaak woord dat ons baie indringend sal moet kyk na hoe ontspanningstyd in suid-afrika tot die grootste voordeel en heil van ons mense se gesondheid aangewend behoort te word. mag die dag aanbreek dat ons in hier­ die land ook sal praat van 'n oefenmalle bevolking, benewens ons sportmalle mense. bronne 1. hamburg, d. a. habits for health. world health forum, 1987, vol. 8, 9-12. 2. meyer, b j. veroudering van mens feite en fabels. festschrift h. w. snyman, 1985 7-10. 3. world health org. tech. rep. ser, 1961 215, 5. 4. brink, a j. jou hart en lewe, 1982, 217, femina uitgewers. 11r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) konsentrasies van kaffben in urine: riglyne vir me atleet departemente van farmakologie en huisartskunde, fakulteitvan geneeskunde, u n ive rsiteit van stellenbosch, posbus 63, tygerberg 7505 hi seifart dr rer nat., d.p. van velden, m.b., ch. b„ m. prax. med., m. esterhuizen, m.b. ch.b., d.p parkin, m.b., ch. b, bsc. hons., pr van jaarsveld, ph.d. bstract a the international olympic committee (ioc) medical commission has placed limits on the use o f caffeine in athletes fol­ lowing evidence that it has ergogenic properties and can be abused in gaining unfair advantage in athletic events requiring stamina. the ioc allows a maximum urine level o f 15ug/mf for this drug and evidence o f higher levels is considered due cause for disdualification. caffeine urinary elimination studies were undertaken in 5 healthy young adult athletes, 2 males and 5 females we conclude from our data that ioc limits will not be exceeded in healthy individuals who ingest diet caffeine and that side effects are likely to limit ingestion o f caffeine concentrate, by casual abusers, to amounts which will not exceed the regulatory norms. inleiding die internasionale olimpiese komitee se mediese afdeling het besluit dat die gebruik van kaffeien deur atlete be perk moet word omdat die middel er gogeniese eienskappe openbaar wan neer dit in hoe dosisse geneem word.1'2'n maksimum vlak van 15ug/mf in urine is vasgestel.5 aangesien kaffeien 'n bestanddeel van 'n verskeidenheid dranke, tonikums en medikamente is wat vry algemeen in geneem word, is daar 'n behoefte onder atlete aan duidelike riglyne oor die hoeveelheid wat ingeneem kan word sonder om die wettige perk te oorskrei. met hierdie doel voor oe het atlete vn/willig verskeie dosisse van 'n kommersiele kaffeien bevattende toni kum (bioplus) en koffie ingeneem en die konsentrasie kaffeien is in hul urine met verloop van tyd gemonitor. metodes bepaling van kaffeien hoedruk vloeistof chromatografie is gebruik vir die kwantitering van kaffeien in urine detail van die metode is soos volg: 'n hewlett packard 1090 apparaat toe gerus met 'n outomatiese monster voerder is gebruik. skeiding is met 'n whatmann partesil c-18 kolom by 35°c bewerkstellig. eluering was isokraties met 4:6 m etanol: water teen 'n vloeis nelheid van 1,5mfvmin. die konsentrasie kaffeien in die eluaat is spektrofotom etries by 254 nm gemeet en met 'n hp 3392 integreerder geregistreer. die minimum bepaalbare konsentrasie was "die internasionale olimpiese komitee se mediese afdeling het besluit dat die gebruik van kaffeien deur atlete beperk moet word omdat die middel ergogeniese eienskappe openbaar wanneerditinhoe dosisse geneem word." 5ng/mf terwyl die standaardkurwe linier was tot 'n konsentrasie van 40ug/mf (r=0,99927). ekstraksie van kaffeien uit urine is direk in die inspuitflessies van die monster voerder gedoen. die ph van 'n 1m£ urine monster is eerstens na 7,4 verhoog deur byvoeging van paar u? (3-5) 3m naoh. dit het veroorsaak dat 100% ekstraksie deur die byvoeging van 200uf mengsel chloroform : isopropanol (98:2) gekry kon word. die urine plus ekstraksie vloeistof is vir 30 min geossileer en daarna gesen trifugeer. die aspirasienaald van die monstervoerder is so gestel dat 10uf van die organiese fase in die skeiding sisteem ingespuit is. vrywilligers vyf blanke atlete het aan die studie deelgeneem. hul ouderdomme was tussen 20 en 25 jaar. verdere beson derhede word in tabel i opgesom toedlening van kaffeien bioplus bevat 9mg kaffeien per me. dit is in dosisse van 100mc, 50mf en 25mf deur die twee manlike atlete geneem wat 'n gemiddelde gewig van 78kg ge had het. die drie vroulike atlete het 50mf, 25mf en 12,5ml' geneem. hul gemiddelde gewig was 58kg. die doser ings is op 'n gerandomiseerde wyse deur die atlete geneem en 'n uit wasperiode van 10 dae is tussen dosisse gebruik. urine monsters is aan vanklik halfuurliks; later uurliks en twee uurliks oor 'n 12 uur periode versamel (vide infra, figure 1 en 2). na elke mon sterneming is die blaas volledig geledig en i50m f water geneem. ten einde met 'n zero waarde te kon begin is kaffeien bevattende vloeistowwe 48 uur voor die begin van die eksperiment uitgesluit. koffie wat 51,8mg kaffeien per 180mf koppie bevat is in hoeveelhede wat wis sel vanaf 4 koppies tot 12 koppies binne een uur na 'n ligte ontbyt geneem. na verloop van die een uur in­ name periode is urine versameling be­ gin soos hierbo met bioplus beskryf. elk van die v yf atlete het slegs een keer op 'n gerandomiseerde wyse een van die december 1987 vol 2, no 4 ,11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) bespreking indien dit wettig sou wees om die kon sentrasie kaffeien in die bloed van at lefie tydens kompetisie te bepaai, sal dit moontlik wees om akkurate bereke nings van die ingeneemde dosis te maak aangesien farmakokinetiese para­ meters soos die volume van distribu sie en opruiming van die middel be kend is (4-6). dit is standaard praktyk om hierdie berekenings vir 'n ander xantienderivaat, teofillien te doen wan neer laasgenoemde vir behandeling van asma gebruik word (sien byvoor beeld 7). die monitor van urine konsen trasies van kaffeien om te bepaai of dit vir sy ergogeniese eienskappe deur 'n atleet misbruik is, is egter nie so een voudig as die monitor daarvan in bloed nie eerstens word slegs 1% van die ingeneemde kaffeien ongemetaboli seerd in die urine uitgeskei.8 dit is ook goed bekend dat die metabolisme van xantiene beinvloed word deur ouder aom, lewerensiemstatus, swangerskap en rook. tweedens varieer urinevloei peweldig met die graad van oefening wat gedoen word. dit is dus moontlik oat n oefening wat na voltooiing ver oorsaak dat 'n klein volume urine in die c io if ^ enwoordig is 'n hoe konsentra­ sie kaffeien tot gevolg mag he. ne«tc!?e^r ^ffei'en in enkele doserings geneem word, is dit duidelik uit figuur en 2 dat maksimum vlakke na 1 tot f j i ur ln die urine verskyn. daar moet inname skedules gevolg. resultate figuur 1 en 2 toon die urine kaffelen vlakke van die manlike en vroulike at jete onderskeidelik. die hoogste vlakke word in albei gevalle in die urine mon­ sters gevind wat 1 tot 2 uur na inname versamel is. hierna neem die maksi­ mum waarde egter nie vinnig af nie dit bly relatief konstant tot ongeveer 4 uur na inname waarna die konsentrasie vin niger begin daal. die gemiddelde maksimum urine vlakke het by die hoogste doserings kafeien (900mg vir mans en 450mg vir dames) nie hoer as i5ug/mf in die eerste 4 uur na inname gestyg nie. duidelike tekens van ongemak (naar heid en bewerigheid) het by hierdie doserings te voorskyn gekom. tabel ii toon die maksimum urine kaffei'envlakke nadat verskillende hoev eelhede koffie ingeneem is. in hierdie eksperiment is die maksimum vlakke na 1 tot v i 2 uur verkry. dit is duidelik van tabel ii dat die inname van koffie teen ‘n maksimum tempo van 12 kop pies per uur (62lmg kaffeien) die uri nevlak tot hoogstens 5,9ug/mf laat styg het. word dit aanvaar dat i5mg/kg die grens is waarby en waarbo newe effekte soos naarheid en bewerigheid ontstaan.8 in die huidige eksperimente was die hoogste doserings slegs 11,5 en 7,8mg/kg vir mans en dames onderskei­ delik. beide groepe atlete het egter by hierdie doserings alreeds ongemak er vaar. 'n selfbeperkende grens op die doelgerigte oormatige gebruik van kaf­ feien bestaan dus indien die gebruiker nie daarvoor gekondisioneer is nie. uit tabel ll is dit duidelik dat inname van koffie teen 'n buitensporige tem­ po van 12 koppies per uur nie die mak­ simale kaffeien konsentrasie in urine verby die vlak van i5ug/mf laat styg het nie hierdie studie bevestig dus dat 'n vlak hoer as 15ug/mf kaffeien in urine slegs te wyte kan wees aan doelbewuste misbruik. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) t y d n a figuur i urinekaffeienkonsentrasie van twee manli­ ke atlete nadat verskillende volumes bioplus geneem is (900,450 en 225mg kaffeien on derskeidelik). tydens elke urine versameling is die blaas volledig geledig en 150m? water tabel i besonderhede van vrywilligers wat aan die proef deelgeneem het. in n a m e ( u r e ) ceslag gewig (kg) aktiwiteit manlik 77 naelloper manlik 79 naelloper vroulik 60 veldatleet vroulik 57 middelafstand vroulik 57 naelloper figuur 2 urine kaffeienkonsentrasie van drie vrouli ke atlete nadat verskillende volumes bioplus geneem is (450,225 en 125,5mg kaffeien on derskeidelik). die gemiddelde gewig van die atlete was 58kg. ander besonderhede is soos in figuur 1. ingeneem. die gemiddelde waardes is ver bind terwyl die vertikale strepe by elke waar de die standaard afwyking toon. die gemid­ delde gewig van die atlete was 78kg. la b e l il maksimale urine kaffeienkonsentrasie na inname van koffie oor een uur aantai koppies kaffeieninhoud (mg) konsen­ trasie (ug/mf) 4 207 1,70 6 310 2,84 8 414 2,74 10 518 3,11 12 621 5,96 urine versameling is halfuurliks gedoen na verstryking van een uur inname pe­ riode dis maksimale konsentrasies is op 1 tot v h uur gevind. t y d n a in n a m e ( u r e ) literatuurverwysings 1. costill dl, dalsky cp, fink w j (1978). effects of caffeine ingestion on metabolism and exercise per­ formance med. sci. sports, 10, 155-158. 2 ivy jl, costill dl, fink wj., lower r.w. (1979). in. fiuence o f caffeine and carbohydrate feedings on endurance performance. med. sci. sports, 1 1 ,6-11 3. delbeke ft. en debackere m (1984). caffeineuse and abuse in sports, int. j. sports. med. 5 , 179-182 4. lelo a , miners jo. robson, r. en birkett d i (1986). assessment o f caffeine exposure: caffeine content o f beverages, caffeine intake and plasma concentrations o f methyl xanthines. clin. pharma­ col. ther. 39, 54-59. 5. lelo a, birkett qj., robson r.a. en miners j q (1986). comparative pharmacokinetics o f caffeine and its prim a ry demethyiated metabolites pa. raxanthine, theobromine and theophylline in man br j. clin. pharmac. 22, 177-182. 6. gilman ag. goodman ls, rail tw. en murad f. (1985) the pharmacological basis o f therapeutics p 1673 seventh edition macmillan publishing com­ pany, new yprk 7. gibaldim en prescott l. (eds) (1983). handbook o f clinical pharmacokinetics. adis health science press, new york 8. rail tw. (1985). the methylxantines. chapter 25 in the pharmacological basis o f therapeutics. se­ venth edition, pp 589-603 (eds., a.g gilman, ls goodman; tw. rail, f murad) macmillan publishing company new york. photograph sa sports illustra ted december 1987 vol 2, no 4,1987 14r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 'glansartikel,r rasioneel-emotiewe terapie vir sportlui professor justus potgieter departement van liggaamlike opvoeding, universiteit van stellenbosch o ati0nal emotive therapy for sportspeople the psychological prob­ lems experienced by sports people are often at­ tributed to irrational thinking. the sportman's cognitions f greatly influence his emotions: as cognitions, emotions and be­ haviour are interdependent ret is based on the fact that the human being is a thinking, judging creature capable o f both rational and irrational thought. irrational thinking leads to dysfunctional be­ haviour thus two people can act differently in a similar ob­ jective situation as a result o f differing interpretations. irrational thinking is often un­ compromising, marked by in­ tense, irrelevant emotions and unrealistic self-demands. un­ reasonable demands o f perfec­ tion can lead to anxiety, frustra­ tion and aggression. such irra­ tional thinking restricts the i .sportsman's capacity to partic­ ipate with spontaneity and to take risks, which leads to a dis­ ruption o f attention focus. 'catastrophing' a second error in thinking, is the tendency to overemphasise the seriousness and trauma o f a situation. together with uncompromising thinking this leads to negative performance, depression and self pity. negative self ju d g ­ m ent in turn can lead to a vi­ cious cycle o f poor m otivation 3nd performance. appropriate outdance can help to redefine distinction between the sportman's view o f his value as a person and his performance on the field. overgeneralisation is often tbbfceab/e in the sportman wno is psychologically poorly upped. a belief that he can­ not win on a certain field or under cer­ tain conditions is irrational selfdeter­ mination that can be rectified through ret. the sport psychologist can edu­ cate the sportsman through cognitive restructuring to grasp that the chief influence is not the objective situation, but his perception thereof. ret is self therapy and the focus o f control lies photograph sa sports illustra ted h p r 1987 vol 2, no 4,1987 with the sportsman. ret provides a structure within which the sportsman can tackle his problems. it also contains a facet o f goalsetting, and employs imagination techniques in order to alter irrational thinking. because ret aims chiefly at restructur­ ing the thinking processes o f the sportsman, no serious resistance to the therapist should come from the coach. the sports­ man's co-responsibility for his progress should avert the nor­ mal stigma attached to ther­ apy algemene sielkundige proble me van sportlui kan dikwels toe geskryf word aan irrasionele denke. omdat die mens se kog nisies, emosies en gedrag inter afhanklik is en mekaar dus wederkerig beinvloed, is dit lo gies om te verwag dat die sportman se kognisies 'n groot invloed op beide sy emosies en sy gedrag sal uitoefen. die ver naamste beginpunt van rasio neel-emotiewe terapie (ret) is dat die mens 'n denkende en oordelende wese is en oor die vermoe beskik om rasioneel sowel as op 'n irrasionele wyse te dink, dit is die mens se irra­ sionele denke wat tot disfunk sionele gedrag lei (moller, 1985) dit gebeur dikwels dat twee persone in soortgelyke situasies verskillend optree. die werklike objektiewe situasie, soos byvoorbeeld 'n kritieke tydstip in n belangrike kompetisie, is vir albei persone dieselfde, maar omdat daar verskillende inter pretasies daaraan geheg word, is die effek daarvan vir die twee persone nie eenders nie. die een deelnemer sal byvoorbeeld onder druk swig, terwyl dit die prestasie van die ander bevord er. die verskil tussen hierdie twee persone se interpretasie van 'n gebeurlikheid is hoof saaklik gelee in die bemiddeling sproses wat jul kognisies speel. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) irrasionele denke en dinkfoute kan die basis van sielkundige swakhede in 'n sportman se mondering vorm. irra­ sionele denke is nie gebaseer op die werklikheid of op feite nie. dit is dikwels absolutisties, gaan gepaard met in­ tense o f irrelevante emosies en verhoed dat die sportman sy doelstel lings bereik. absolutistiese denke een van die mees algemene dinkfoute is absolutistiese denke waarmee die sportman onrealistiese eise aan hom self en die situasie stel. dit kom gewoonlik in sy selfspraak tot uiting in sulke gedagtes soos "moet", “moenie" en “behoort" onredelike eise van per feksie kan lei tot angs, frustrasie en soms tot onvanpaste aggressie. hierdie aggressie word dikwels na binne gerig en dit kom tot uiting in 'n onverdraag same gesindheid van die sportman teenoor homself en sy feilbaarheid. as gevolg van hierdie irrasionele denkwyse laat hy homself me genoeg ruimte om spontaan mee te ding of risiko's te neem nie. hy plaas onnodige druk op homself wat tot angs, woede en ag­ gressie kan lei. verder vind daar ook 'n ontwrigting van aandagsfokus plaas, omdat die sportman selfgerig raak. daar word nie voorgegee dat die sport­ man emosieloos moet wees of homself moet vereenselwig met gemiddeldheid nie, maar absolutistiese, perfek tionistiese, onredelike of onrealistiese denke wat prestasie inhibeer, is gewoonlik die basis van probleme in die sportman se ego-kompetisie. katastrofering katastrofering is 'n tweede tipe dink fout. dit is die neiging om situasies as veel ernstiger of meer traumaties te sien as wat dit in werklikheid is. dit sluit aan by absolutistiese denke in die sin dat die sportman se vorige swak ver tonings of kleiner foute, selfs binne dieselfde kompetisie, op so n wyse geinterpreteer word dat dit sy huidige en toekom stige w e rk ve rrig tin g negatief beinvloed. dit kan ook tot uit­ ing kom in depressie en 'n verlengde periode van swak vertonings wat in werklikheid niks met tegniek, vaardig heid of fisieke vermoens te doen het me. 'n verdere gevolg van hierdie tipe denke is 'n lae frustrasiedrempel met gepaardgaande selfblaam, selfbejam mering en depressie. die neiging tot negatiewe selfbeoordel ing wat op irrasionele denke berus kan ook aanleiding gee tot swak vertonings dit kan ook 'n bose kringloop ontket en wanneer die sportman begin twyfel oor sy eie vermoens en dit gevolglik sy m otive rin g en gepaardgaande prestasie negatief beinvloed. baie sportlui ervaar periodes van vertwyfel ing en kan deur middel van gepaste voorligting deur hierdie krisisperiodes gehelp word. die sportman wat nie rasioneel kan on derskei tussen sy waarde as persoon en sy prestasie op sportgebied nie, deur dat hy sy eiewaarde aan sy fisieke prestasies koppel, gaan gewis in een of ander stadium probleme in hierdie ver band ondervind dit lei me net tot die gebruiklike "gebrek aan selfvertroue" nie, maar kan die sportman se selfkon sep en selfwaarde negatief affekteer oorveralgemenings oorveralgememngs is baie dikwels ken merklik van die sportman wat sielkun dig swak toegerus is vir kompetisie. hy bou 'n sielkundige blokkering op teen sekere spelers en glo dat hy hulle nooit sal kan klop me. ander voorbeelde is spelers wat daarvan oortuig is dat hulle onder sekere omstandighede, soos byvoorbeeld op spesifieke bane of velde, nooit suksesvol is of sal wees nie hierdie irrasionele selfindoktrinasie of selfsuggestie kan deur herindoktrinasie deur middel van ret reggestel word. ongeldige afleidings uit bepaalde ge beurtenisse wat nie deur feite onder steun word nie, soos byvoorbeeld die sportman se persepsie dat hy nikswerd is omdat hy op 'n sekere wyse opgetree het of 'n punt afgestaan of 'n kom­ petisie verloor het, kan 'n ontwrigtende invloed op sy sielkundige benadering he. die sportsielkundige kan n belangrike voorligtingsrol vervul deur saam met die sportman bogenoemde en ander irrasionele denke en dinkfoute te iden tifiseer, te betwis en te wysig en te ver"oorveralgemenings is baie dikwels kenmerklik van die sportman wat sielkundigswak toegerus is vir kompetisie:' vang met rasionele denke. deur middel van kognitiewe herstrukturering word die sportman opgevoed om te besef dat dit nie die objektiewe situasie is wat hom soseer beinvloed nie, maar sy per­ sepsie van die situasie. die doel van rasioneel-emotiewe terapie is dus om die sportman te help om insig in die in houd van sy denke, denkprosesse, en selfkommunikasie te verkry en sy gesindhede, oortuigings en filosofie te wysig om sodoende sy doelstellings op n rasionele wyse te bereik. ret is selfterapie daar word voorgestel dat hierdie tipe terapie geskik vir sportlui sal wees om­ dat dit in groot mate selfterapie is. die fokus van kontrole berus dus by die sportman self. die keuse tussen ra­ sionele en disfunksionele denke is sy eie. hy dra dus medeverantwoordelik heid vir sy terapie. hierdie benadering behoort by die persoonlikheid van die meeste sportlui te pas. sportlui be­ hoort ook me probleme met die didaki tiese inslag te ondervind nie, omdat hulle uiteraard ontvanklik vir onderrig en afrigting is. verder skep die werkswyse van ret heelwat struktuur en 'n raamwerk waa rin die deelnemer sy probleme kan aani pak. dit bevat ook 'n faset van doelwit stelling... lets waarmee die ernstige deelnemer vertroud behoort te wees. i ret maak ook gebruik van verbeeld ingstegnieke om irrasionele denke te identifiseer en te wysig. omdat die meeste sportlui van een of ander vorm van beeldingstegniek gebruik maak as deel van hul sielkundige voorbereiding, behoort dit goed in te pas by die sport­ man se normale program, n verdere voordeel van ret vir die sportman is dat dit vereis dat die klient goed vertroud moet wees met die ra sionaal en die werkswyse van die ter­ apie voordat daar met werklike terapie begin kan word. dit behoort die sport­ man se motivering asook die geloof waardigheid van die terapeut te bevorder omdat sportlui sielkundig redelik taai is, behoort hierdie terapie, wat in teen stelling met byvoorbeeld die rogeri aanse benadering redelik aktiefi direktief en soms bedreigend of uit dagend mag voorkom, nie ernstige verhoudingsproblem e tussen die sielkundige en die sportman te veroor saak nie. die moontlikheid van weer stand deur die afrigter omdat hy mag voel dat die voortigter op sy terrein oor tree, word in groot mate verminder deurdat die onmiddellike doel van ret is nie om die sportman se gedrag as sodanig te wysig nie, maar om die in houd van sy denke asook die wyse waarop hy dink te rekonstrueer die feit dat die sportman self verant woordelik gemaak word vir sy vorder ing en dat hy insig in die werkswyse en doelstellings van ret moet he, behoort die stigma wat daar moontlik aan sielkundige hulp kleef en die gevolglike traagheid van die sportlui om hulself aan te meld vir terapie, uit die weg ruim. verwyslng moller, andr6 t. (1985), rasioneel-emotiewe terapie in die praktyk stellenbosch: universiteit-uitgewers _____________________ december 1987 vo l 2, no 4 ,19< r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) f sasma nuus sasgv news dr d. van velden head: department of family practice. n die suid-afrikaanse sportgeneeskunde ver emging se pogings om 'n nasionale bewuswording te kweek van die belang van fiksheid as gesond heidsbevorderende maat reel, is ons besonder bevoorreg om in hierdie uitgawe 'n artikel te publiseer van dr f. r retief, direkteur-generaal, departement van nasionale gesond­ heid en bevolkingsontwikkeling, insake die plek van oefening in gesondheids­ bevordering. dit is bemoedigend om te weet dat die departement van nasion­ ale gesondheid en bevolkingsontwikkel ing, so 'n hoe premie plaas op gesond­ heidsbevordering in die nasionale gesondheidsplan wat in 1986 afgekon dig is die sasgv sal alles binne sy ver­ moe doen om by wyse van weten skaplike artikels, simposia en kongresse, 'n motiveringsaksie te loods ter bevor dering van 'n gesonder leefwyse sodat gesondheidsbedreigende gedrag grootliks uitgeskakel kan word. dit is al gemeen bekend dat die suid-afrikaanse leefwyse aanleiding kan gee tot 'n vlaag van sogenaamde "hipokinetiese siektes” wat nie geneesbaar is met die tradi sionele allopatiese geneeskunde nie, maar eerder met 'n gestruktureerde oefenprogram wat op 'n nasionale ba­ sis georganiseer word. aangesien so 'n poging op 'n multidissiplinere benader ing rus, is die sasgv verheug dat die aanverwante mediese dissiplines soos dv, fisioterapie, biokinetika, maat skaplike werk, ensl, nou ook lid kan word van ons vereniging om ons hande te sterk in hierdie taak. the editorial board of the sports medi­ cine journal had a very successful meeting recently where the format of tne journal was discussed in depth. in­ ternational recognition is to be persued some opposition to become af­ filiated with the international sports medicine association (f.l.ms.) and to comply with their motto for 1987: "lets trv? example to the world. lets work « w t n e r for sports medicine, exercise, a * ; ancl a better understanding ong our nations'! a concentrated ef­ margaret simpson, continuing medical education university of natal po box 17039, congella 4013. tel no: (031) 25-4211. provisional programme wedsnesday. 6th a p ril 1988 registrations welcoming drink thursday: 7th a p ril 1988 welcome by president motivation / perspiration / inspiration biomechanics of running drugs in sport fluid balance morphalegic considerations diet — fads & fancies liniments, strapping and bandaging endotoxaemia in long-distance runners advice for the beginner running equipment footwear friday: 8th a p r il 1988 foot anatomy & biomechanics skin problems in the runner physical examination of the ankle and foot stress fractures compartment syndromes foot soft tissue problems: tendonitis/fascitis physical examination of the knee internal derangement of the knee joint tendon problems around the knee joint anterior knee pain in runners muscle tear treatment in runners medical aspects of the iron man triathlon the assessment of fitness of middle aged persons to participate in strenuous sporting activities banquet saturday: 9th a p ril 1988 fun run open session key address & panel discussion speakers will include prof t noakes dr e p hugo mr s n du toit dr dp van velden drrrathgeber dr c noble mr g lindenberg dr j skwono december 1987 vol 2, no 4,1987 fort should be made to increase our membership and to disseminate our journal as widely as possible to all ap­ propriate health professionals. the south african sports medicine as­ sociation is deeply in debt to the spon­ sor of our journal and would like to ex­ press our sincere appreciation for their concentrated efforts to enhance the teaching and practice of sports medi­ cine in south africa. dr. van velden sasma update 88 course the cme course, concentrating on var­ ious medical and physiological aspects of running, scheduled for 6-9 april 1988, is another venture of the sasma to dissem inate sports medicine knowledge to everybody involved in sport and exercise for further information please contact: dr r rathgeber, 112 hillcon towers, umhlanga rocks 4320 chairman: tel: 031 561-1777 orr ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) prevention of rugby injuries should more be done? etienne p. hugo, chairman: sa rugby board medical advisory committee s a has reached the end of the 1987 rugby season. there has again been a justifiable concern from many interested groups for the safety of the play­ ers during this year. some sections of the medical profes­ sion on media are always ready to cre­ ate sensation or denigrate rugby or preferably both by headlining any seri­ ous injury whilst ignoring similar inju­ ries occuring in activities like motor cy­ cling and other sports. it will be proclaimed on each occasion that the controlling body of the game has done nothing and that the "laws must be changed" or "new laws must be introduced". those with genuine concerns for the game will want evi­ dence of what might lead to justifia­ ble changes some perspective is need­ ed by looking at what has been done and what has happened in recent years. the game of rugby is under control of the international rugby football board. the board is composed of 2 represen­ tatives from each of the unions in membership including south africa. the laws of the game or any alterations therein or interpretations thereof are promulgated by the board. the board's concern about safety and health matters related to rugby led to the establishment of a medical adviso­ ry committee and south africa was represented on this committee since the beginning. this immediately led to medical advi­ sors or advisory committees to the various unions, medical doctors accom­ panying touring teams, doctors at representative touring matches as well as the stimulation of interest and research into injuries, commonly as­ sociated with rugby. the board has introduced various changes, intended to improve the game for the players and spectators and the safety of the players has be­ come a major consideration during the last 10 years. law amendments were introduced in an endeavour to minimise unintention­ al injuries. various facets of the game came un­ der scrutiny e.g., the tackle and lying on the ground, scrums, rucks, mauls and foul play where deliberate injuries can occur. the medical advisory committee was responsible for very important recom­ mendations which have been accept­ ed regarding: • the use of drugs in rugby • dangers of footwear and damage from studs • use of mouth guards • training and fitness • replacement of injured players • dangers of concussion • the need of injured players to leave the field the board conducted a special study into the frequency and type of rugby injuries and it is involved in an analysis of all severe spinal injuries due to rug­ by as well as the assessment of the value o f mouth guards. the s.a.r.b. medical committee is ac­ tively involved and committed towards these programmes. the i.r.f.b. has been responsible for more than 30 law amendments, 14 notes or instructions to referees, and more than 20 directives to improve the position of the player. it is unacceptable to state that the board has been unresponsive to change and to make the game a safer one the referee plays a vital role in the im­ plementation of the rules but the failure of referees to apply the laws of the game is not in itself an adequate reason for altering the laws. officials, selectors, managers and even team doctors, develop tunnel vision in relation to their own team. players are allowed to play after receiving injec­ tions into painful areas or joints or they are allowed to play one week after be­ ing carried o ff the field with concus­ sion. the s.a.r.b. has recommended mini­ mum medical and first aid require­ ments at all rugby playing fields. the effective implementation of these requirements and essential profession­ al care at playing fields have become a pre-requisite for playing the game players and parents at schools have the right to demand certain basic precau­ tions and available facilities. the establishment of these facilities re­ mains the responsibility of the school, club or union. if these demands are not met, the ef­ fective protection by the laws of the game or the suggested minimum first aid requirements will have little effect. closer co-operation between players, parents, administrators and doctors is needed to improve the standard of care further, december 1987 vol 2, no 4,1? r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) basic conditioning for rugby dr keith cordon — team physiotherapist o ugby being an amateur game largely precludes any o ff season training program, and the best that can be hoped for is that 6 weeks before the new season begins, the players will put in some form of aero­ bic training, the activity of choice be­ ing running. for maximal aerobic ef­ fect, between 20-45 minutes should be run on alternate days. a basic weight training program emphasising hyper­ trophy is strongly recommended for between 6 12 weeks during the off-season. once the players return to organised practices (usually towards the end of january), training emphasises the build­ ing of stamina and this was effective­ ly achieved by hill climbing. a t eben cuyler where the team practises, there is a fairly steep incline (35 degrees) of approximately 40 metres and the team builds up to 20 hills. one of the problems experienced here was the development of inflamed achilles tendons, and it would be advis­ able to start with only 2-4 hills and add 1-2 a week as the season progresses. during the season hill climbing is phased out due to the demands of the game and the need for more specific fitness to be developed. a t this stage more intense, shorter and faster activi­ ties replace hill climbing. it must be remembered that rugby is not an en­ durance event, and a number of in­ teresting statistical factors which should have an important influence on the specificity of training have been demonstrated. for example during an eighty minute game, there are on aver­ age 140 seouences of action lasting 27 minutes of actual playing time as it has also been obsetved that 56% of the ac­ tivity lasts less than 20 seconds and 85% of the activity lasts less than 20 seconds, it means that the energy source is predominantly atp-cp plus the anaerobic lactic acid system. we see therefore that at all standards of competition high levels of anaerobic power and capacity are required, and "it must be remembered that rugbylsnotan endurance event" their development must receive more attention than is currently the case. to achieve this the players must be put through a series of tests to measure: 2. 6. muscular strength, muscular endurance, cardiovascular endurance, flexibility, leg explosiveness, quickness, agility, percentage body fat. the question most often asked is: what is the role of testing if the tests do not measure playing ability? the answer is that the tests measure potential abili­ ty which could mean that the player who achieves high scores has the tools to become a great player. strength training (weight training) should be encouraged and if it could form a part of the conditioning pro­ gram would contribute significantly to the players realising their individual potential. there is no american or east european athlete today who is not on an intensive weight training program. the benefits in terms of developing the players physical capacity factors that will enable them to fulfill their potential and minimise tim e o ff through injury have been proven con­ clusively by our american, eastern eu­ ropean and russian counterparts, warm-up: before every practice and game the team was warmed up very systemati­ cally as follows: five minutes of run­ ning, hopping, jumping to get the cir­ culation going, followed by slow stretches to every joint and muscle act­ ing over that joint. before a game, a few plyometric (rebound jumping) ex­ ercises are included to stimulate the "reactive neuro-muscular apparatus". this is brought about by loading the elastic and contractile components of the muscle the actual warm-up should take between 10 and 20 minutes, de­ pending on the fitness level, tempera­ ture and nature of activity it precedes conclusion: in addition to improving performance, one of the primary benefits of ade­ quate physical conditioning is to minimise the occurence and severity of injuries. the incorporation of proper testing to provide information as to the players physical capability, super­ vised strength training, adequate rest and nutrition will ensure the rugby players spend less time in the treat­ ment rooms and more time on the playing field. rtq and trauma. diclophenac sodium 50 mg (entericcoated tablets) reg.no,m.1/253 (wemctioi/1965) ej c ib a g e ig y (pty) ltd p.o. b o x 9 2 is a n d o 1 6 0 0 f o r fu ll p re s c rib in g in fo r m a tio n p le o se re fe r to th e m .d.r. m e m b e r 1987 v o l 2, n o 4,1987 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) news the ponky firer sports medicine aw ard south african medical authors with an interest in the growing gfield of sports medicine will be pleased to learn of the establishment of a new writing award. the firer sports medicine award will take the form of an annual cash prize of r500 presented in recognition of an important written contribution in sports medicine by johannesburg or­ thopaedic surgeon, dr 'ponky' firer certain principles are laid down for the guidance of contributors.<1 • the objective is to encourage good, well presented and concise contribu­ tions to the growing literature on sports medicine. • open to south african authors, criter­ ia for evaluation will include good research and sound methodology. written contributions not exceeding 1500 -1800 words and dealing with any sports medicine-related topic are invi­ ted. ideally, the work should represent per­ sonal experience and should provide concise/practical help to gps and others periodically involved in the management o f injuries, training schedules or the physiology of sport. articles must be available for publica­ tion in "sports medicine" prior to, or fol­ lowing judging. the editorial board of the publication will nominate three ar­ ticles from which one winner will be chosen by an appropriate academic authority. drugs and sport congress the national symposium on drugs and sport participation to be held at the sports centre, university o f pretoria, is scheduled for 26 february 1988. an in­ ternational speaker will participate and the sasma is officially involved in the programme this promises to be very informative and further information can be obtained from gert potgieter or petra taljaard at tel. no (012) 542-2150. drug abuse in sport and in the commu­ nity is becoming a major problem and needs to be addressed from many different angles. the 7th international biochem istry o f exercise conference, london, ontario, canada june 1-4 1988. tentative programme the role of functional demand in regulating gene expression. determinants of muscular growth — a biochemical perspective. muscle energetics — phosphorylation of the contactile protein. metabolic disorders of the muscle — exercise implications. fluid, electrolyte, and acid-base homeostasis in the working muscle. extramuscular substrate deliver/ and control with exercise. the biochemistry of muscular fatigue. poster sessions adaptation and muscle transformation. skeletal muscle growth. metabolic disorders of the body. fluid and electrolyte balance. substrate utilization and exercise skeletal muscle fatigue. suid-afrikaanse sport geneeskunde vereniging application form aansoekvorm south african sports medicine a ssociation full member/vohe lid r25 student member/studente-lid r5 tel no/tel n r . ................ m a s a no/mvsa nr . f u ll m e m b e r m e d ic a l p /a c tin o n e r rs w h o a re m e m b e rs o f m a s a v o ile l id : m e d ie s e p ra k tis y n s w a t le d e v a n d ie m.v.s. a. is . s tu d e n t m e m b e r . m e d ic a l s iu d e m s in c lin ic a l y e a rs s tu d e n t e le d e :m e d ie s e s t u d e n ie m h u lk lin ie s e ja re. a p p lic a tio n s to r m e m b e rs h ip o f s. a .s .m a s h o u ld b e s e n t to. the s e c re ta ry . s a s m .a h a tfie ld f o ru m w e s t. 1067 a rc a d ia s tre e t. h a tfie ld . p re to ria 0 0 8 3 . c h e q u e s to a c c o m p a n y m e m b e r s h ip fo rm december 1987 vol 2, no 4,11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research 1 sajsm vol. 29 2017 concussion knowledge and attitudes among amateur south african rugby players c t viljoen,1 b phys t, msc physiotherapy, m schoeman,2 bsc (human movement sciences), bsc (hons) (biokinetics), phd (biomechanics), c brandt,1 bsc physiotherapy, msc physiotherapy, phd physiotherapy, j patricios,3 mbbch, mmedsci, facsm, ffsem (uk), ffims, c van rooyen,2 bcom, mcom 1department physiotherapy, university of the free state, south africa 2 department biostatistics, university of the free state, south africa 3 section sports medicine, faculty of health sciences, university of pretoria, and department of emergency medicine, faculty of health sciences, university of the witwatersrand, south africa corresponding author: c t viljoen (viljoen.ct@gmail.com) rugby players are exposed to a higher risk of injury than participants in other sports, as players may legitimately be involved in collision incidents.[1] a recent review reported that head injuries, including concussions, are the most frequently reported injuries in professional rugby.[2] concussion is defined as a ‘traumatically induced transient disturbance of brain function which involves a complex pathophysiological process’.[3] potentially dangerous long-term side-effects, such as neurological deficits and chronic traumatic encephalopathy, explain why the topic of concussion is covered extensively in medical and lay media.[4] concussion in rugby is most commonly noted at community/amateur level, with a rate of 2.08 concussions per 1 000 player match-hours.[5] this is followed by schoolboy level and elite level, with respective rates of 0.62 and 0.40 concussions per 1 000 player match-hours.[5] most of south africa’s rugby playing population consists of amateur players. only a limited proportion of amateur clubs and schools offer medical assistance – which is limited to matches – mostly due to a lack of funding.[6] therefore the focus of the boksmart programme in south africa currently leans towards educating coaches and referees to recognise concussion signs and symptoms and to remove concussed players from the field.[6] in a country where medical assistance on the field during a rugby match is scarce, the players themselves can play a pivotal role in reporting possible concussions to their coach or the referee. only a few studies have researched rugby players’ knowledge of concussion.[7–9,11,12] less than half of a group of new zealand high school rugby players knew about concussion, while only 22% of players waited to be medically cleared for return to play (rtp) after being diagnosed with concussion.[7] research among italian amateur rugby players showed that 39% of these players had never been informed about concussion.[8] similar results were noted among 127 subelite south african rugby players, where less than half of the players waited until fully recovered before returning to full participation in rugby.[9] currently, no rugby safety management programme focuses on concussion education among south african rugby players. only a single study, to date, has investigated knowledge of concussion and rtp attitudes among south african rugby players and therefore further research in this field of study is warranted.[9] the aim of this study was to evaluate the concussion knowledge and attitudes to rtp of south african amateur rugby players in order to provide information for future concussion education programmes. based on anecdotal evidence and the study by walker,[9] it was found that amateur south african rugby players displayed insufficient knowledge concerning concussions. methods permission to conduct this study was granted by the south background: the south african rugby union’s boksmart programme currently educates coaches and referees on concussion. rugby players are often more familiar with their teammates than the coach or referee. therefore they are wellpositioned to play a pivotal role in rugby safety if they have adequate knowledge to identify subtle signs and abnormal behaviour displayed by a concussed teammate. however, no programme focuses on concussion education among south african rugby players and there is a dearth of literature on concussion education programmes among rugby players which could lead to safer return to play (rtp) habits. objectives: to evaluate south african rugby players’ concussion knowledge and attitudes/behaviours regarding rtp following a concussion. methods: a descriptive, cross-sectional study was used. participants (n=294) were divided into junior amateur high school (jahs) (n=216) and senior amateur club (sac) (n=78) players. the modified rockas-st questionnaire was used to evaluate their concussion knowledge index (cki) and concussion attitudes/behaviours index (cai) regarding rtp. results: on average, 62% (jahs) and 60% (sac) of the cki questions were answered correctly. jahs participants correctly identified 66% of concussion symptoms, similarly to the sac participants (63%), rendering similar (p=0.37) overall cki scores when comparing the two groups. the cai questions yielded similar (p=0.98) results between the groups, reporting safe responses in 66% (jahs) and 67% (sac) of the items. discussion and conclusion: junior and senior south african amateur rugby players lacked approximately one-third of essential concussion knowledge, which may lead to a display of unsafe attitudes/behaviours to concussion and rtp. further research is warranted to inform educational programmes on concussion among rugby players. keywords: post-concussion syndrome, rugby union, return to play, safety, south africa s afr j sports med 2017;29:1-6. doi: 10.17159/2078-516x/2017/v29i0a1942 mailto:viljoen.ct@gmail.com http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1942 original research sajsm vol. 29 2017 2 african rugby union and the gauteng department of education, while ethical approval was obtained from the institutional ethics committee of the university of the free state. a total of 294 south african amateur rugby players participated in this cross-sectional study and were recruited from high schools and clubs in the gauteng province. from the more than 200 schools in gauteng who were actively playing rugby at the time of the research, 30 schools were randomly selected and approached to participate in the study. from these schools, seven agreed to participate. all gauteng province-based rugby clubs with contact details available on the internet or via the specific rugby unions were contacted for inclusion in the study. six rugby clubs finally agreed to partake in the study. the study sample was divided into two groups of players, namely, those from junior amateur high school (jahs) (n=216, aged 13–19 years) and those from senior amateur club (sac) (n=78, aged 17–28 years). all participants had to be male, south african citizens, and proficient english-speaking rugby players. participants in the sac group had to be registered at a club in the gauteng province during the 2015 club rugby season, and must have played at least one game for the club that season in either the under-21 or the over-21 age groups. participants in the jahs group had to have been playing at under-14, -16 or -18 age levels during the 2015 season, be enrolled at a gauteng school, and have played at least one game for the school during the 2015 season. participants completed a modified rosenbaum concussion knowledge and attitudes survey – student version (rockas-st) questionnaire [10] to assess their knowledge and attitudes/behaviour regarding concussion injuries and rtp. the original questionnaire consisted of the concussion knowledge index (cki), concussion attitudes index (cai) and the rockas concussion symptom recognition checklist.[10] the modified version replaced the rockas concussion symptom recognition checklist with a 16symptom checklist which increased the reliability and validity of the questionnaire.[10] descriptive statistics were used to summarise continuous data with means and standard deviations or medians and quartiles (q1 and q3) as appropriate. frequencies and percentages were calculated for categorical data while significance was set at p<0.05 for comparative analyses. results at the time of the study, 33% from the jahs and 42% from the sac groups’ participants reported a previous history of having sustained a concussion. the largest proportion jahs participants were front row players (26%) while the largest proportion of sac participants were in the back three (27%) (fig. 1). the jahs group had a median rugby playing experience of eight years (q1=7; q3=10) compared to the sac group with a median of 10 years (q1=6; q3=15). sixty percent of the sac participants were under-21 players. only 46% (n=133) from the total sample had previously received information on concussion. a higher number of participants in the sac group were more informed on concussion (59%, n=44) compared to participants in the jahs group (41%, n=89). healthcare professionals (hcp) played the biggest role as the source of information to 42% (n=43) of all participants. those who had previously received concussion information reported hcps as their information source. the jahs group, specifically, received the majority of their information on concussion from hcps (47%, n=34), while the sac group received their information on concussion from the schools (33%, n=10) they had previously attended (fig. 2). the cki mean in the jahs group was 11±2 (range 3–15) of a maximum score of 17 points, while the sac group showed a mean of 10±2 (range 4–14) also of a maximum score of 17 points. participants in the jahs group, on average, identified 62% of the cki questions correctly, which was similar compared to the 60% identified correctly by the sac participants (p=0.37). most of the knowledge questions were correctly answered by less than 80% of the jahs participants (table 1). the most common misconception was that a concussion could be identified via brain imaging; only 23% (n=50) of the jahs group and 19% (n=14) of the sac participants answered this question correctly. both groups had a misconception about the mechanism of the concussion injury, as 63% (n=133) of the jahs 0,0 5,0 10,0 15,0 20,0 25,0 30,0 p e rc e n ta g e ( % ) player positions jahs sac 0,0 5,0 10,0 15,0 20,0 25,0 30,0 35,0 40,0 45,0 50,0 p e rc e n ta g e ( % ) jahs sac fig. 1. player position distributions of the junior amateur high school (jahs, n=216) and the senior amateur club (sac, n=78) participants. fig. 2. sources of information on concussion received by the junior amateur high school (jahs, n=72) and the senior amateur club (sac, n=30) participants. original research 3 sajsm vol. 29 2017 and 57% (n=44) of the sac participants believed that a concussion could only be sustained by a direct hit to the head. interestingly, only 32% of the jahs group knew that multiple concussions can have a negative long-term effect on a player’s health and well-being (table 1, item 14). when the same concept was tested in a scenario they could relate to, then 81.9% of the jahs group answered correctly. similarly, the sac group’s correct answer percentage increased by 15.5% when the concept was tested in a playing scenario they were familiar with. on average, participants in the jahs group identified the symptoms of concussion correctly 66% of the time compared to 63% by sac participants. true symptoms of concussion that were unfamiliar to the majority of jahs and sac participants included sleep disturbances, loss of consciousness and nausea (table 2). dizziness and headaches were the symptoms that both the jahs and sac groups were most familiar with. similar (p=0.98) mean cai scores were noted for both groups (table 3). the cai mean in the jahs group was 57±9 (range 36–75) compared to 56±11 (range 20–75) reported among the sac participants. the cai questions were scored on a likert scale and categorised into "safe", "neutral" and "unsafe" responses. participants in the jahs group had a mean safe response of 66% compared to 67% for sac participants when analysing the total number of safe, neutral and unsafe responses across the various statements. the majority of jahs (79%, n=169) and sac participants (85%, n=63) agreed that a concussed player must be prevented from returning to play by the coach, even if it means losing the game (table 3, scenario 1.1). both the jahs and sac participants showed unsafe responses to the question of sports participation while concussed. only 55% of jahs (n=115) and sac (n=43) participants reported that they themselves would take the decision to refrain from participation in sport while they still had symptoms that resulted from a concussion (table 3, statement 1). only 66% (n=141) of jahs participants believed that a physiotherapist rather than the player should decide when it is safe to rtp. the sac participants showed similar results, as only 53% (n=40) agreed that the player should not be the one making the rtp decision. a slight decline in safe rtp responses (1% for jahs and 4% for sac participants) towards a hypothetical scenario were noted when playoff games were in question compared to the first match of the season (table 3, scenario 2). however, when distinguishing between those who "strongly disagreed" and those who just "disagreed", only 28% of the sac participants strongly disagreed that the player table 1. concrete statements and scenarios evaluating the concussion knowledge index (cki) of the jahs and sac groups. statements % correct true statements jahs sac 1. there is a possible risk of death if a second concussion occurs before the first one has healed. 82 77 2. people who had one concussion are more likely to have another concussion. 66 48 3. symptoms of a concussion can last several weeks. 80 80 4. after 10 days, symptoms of a concussion are usually completely gone. 60 53 5. concussions can sometimes lead to emotional disruptions. 72 66 6. an athlete who gets knocked out after getting a concussion is experiencing a coma. 38 37 false statements 7. in order to be diagnosed with a concussion you have to be knocked out. 79 74 8. a concussion can only occur if there is a direct hit to the head. 37 43 9. being knocked unconscious always causes permanent damage to the brain. 70 67 10. sometimes a second concussion can help a person remember things that were forgotten after the first. 68 81 11. after a concussion occurs, brain imaging (cat scan, mri, x-ray etc.) typically show visible physical damage (bruise, blood clot) to the brain. 23 19 12. if you receive one concussion and you have never had a concussion before, you will become less intelligent. 86 94 13. after a concussion, people can forget who they are and not recognise others but be perfect in every other way. 44 27 14. there is rarely a risk to long-term health and well-being from multiple concussions. 32 53 scenarios 1.1. a single concussion will affect a player’s health and well-being negatively 65 69 1.2. a history of multiple concussions will affect a player’s health and well-being negatively 82 67 2. playing with concussion symptoms will not affect a player’s performance 76 72 jahs; junior amateur high school, sac; senior amateur club table 2. concussion symptom identification capabilities of the jahs and sac groups. symptom % correct the following are symptoms jahs (n=216) sac (n=78) amnesia (memory loss) 69 56 blurred vision 73 72 confusion 77 69 dizziness 84 71 headache 84 77 loss of consciousness 47 56 nausea 57 51 sleep disturbances 38 47 the following are not symptoms abnormal sense of smell 92 88 abnormal sense of taste 88 87 black eye 91 86 chest pain 83 91 nosebleed 73 85 numbness/tingling in upper extremity 79 76 sharp burning pain in neck 85 85 weakness of neck range of motion 59 60 jahs; junior amateur high school, sac; senior amateur club original research sajsm vol. 29 2017 4 should rtp during a playoff game compared to 40% who strongly disagreed when it was the first match of the season. discussion as far as could be established, this was the first study including both junior and senior amateur rugby players, comparing data relating to concussion knowledge and attitudes/behaviours. this study sample (294 participants) is substantially larger when compared to other studies that investigated concussion knowledge among rugby players.[8,9,11,12] only 46% of the total study sample had previously received information on concussion, which is marginally more than the 39% informed participants reported for italian rugby players.[8] a better-informed sample was reported by sye et al.,[7] where 61% of their participants had received concussion information. the fact that more sac (59%) compared to jahs (41%) participants from this study reportedly received concussion information may possibly be attributed to the fact that they also had a higher reported incidence of concussion and player years and, therefore, possibly greater exposure to concussion management and associated concussion information. due to the fact that the participants from this study were amateur school and club players not necessarily playing in a specific position, with a median rugby playing experience of eight and 10 years respectively, the participants were more likely to have changed player positions during their rugby careers. this would make inferences on the link between player positions and concussion histories speculative at most, since the participants reported their concussion histories irrespective of when they occurred. similarly to previous studies,[8] hcps played the biggest role as a source of information to 42% of the informed participants. schools were also identified as a noteworthy source of information (fig. 2). these should be investigated in future research as a possible avenue for concussion education among rugby players who are at different developmental stages compared to the coaches and referees targeted by boksmart. it must be acknowledged that teammates could inherently be part of the school source for concussion information and should also be considered in future research. as boksmart focuses on educating coaches and referees on concussion,[6] it was expected that coaches would have played a pronounced role as a source of concussion information. however, only 14% of the jahs and 7% of the table 3. concrete statements and scenarios evaluating the concussion attitude index (cai) of the jahs and sac groups. % correct jahs sac statements % safe % neutral % safe % neutral 1. i would continue playing a sport with a headache as a result of a concussion. 55 29 55 27 2. i feel that coaches need to be extremely cautious when determining whether an athlete should return to play. 72 22 80 13 3. i feel that concussions are less important that other injuries. 66 23 75 17 4. i feel that an athlete has a responsibility to return to a game even if it means playing while still experiencing symptoms of a concussion. 63 18 69 22 5. i feel that an athlete who is knocked unconscious should be taken to the emergency room. 77 15 72 21 scenarios 1.1. i feel that the coach made the right decision to keep a fellow concussed team mate off the field, even though we lost the game. 79 12 85 7 1.2. my team mates would feel that the coach made the right decision to keep a fellow concussed teammate off the field, even though we lost the game. 60 26 67 23 2.1. i feel that a concussed player should have returned to play during the first game of the season (that is, the same game of the injury) 67 20 65 20 2.2. most players would feel that a concussed player should have returned to play during the first game of the season (that is, the same game of the injury) 56 27 65 16 2.3. i feel that a concussed player should have returned to play during the semi-final playoff game 67 19 61 27 2.4. most athletes feel that a concussed player should have returned to play during the semi-final playoff game 52 25 61 20 3.1. i feel that the physiotherapist, rather than the player, should make the decision about a player returning to play 66 21 53 31 3.2. most players would feel that the physiotherapist rather than the player should make the decision about returning a player to play 57 30 57 29 4.1. i feel that a player with concussion symptoms should tell the coach about the symptoms even if its two hours before the game. 76 17 77 14 4.2. most athletes would feel that a player with concussion symptoms should tell the coach about the symptoms even if it is two hours before the game 72 20 62 28 jahs; junior amateur high school, sac; senior amateur club original research 5 sajsm vol. 29 2017 sac participants reported coaches as their source of information on concussion. considering the fact that teachers often fill the role of rugby coaches, it must be acknowledged that some jahs participants included teachers as opposed to coaches as a school source of information. in contrast, the low occurrence of coaches conveying concussion information reported by the sac players could not be explained and seems to imply that coaches are not a significant source of concussion information among senior amateur rugby players. a third (33%) of sac participants also reported schools as their main source of concussion information, due to the fact that 60% of the sac participants were under-21 players and had therefore recently attended school. similar to the findings of boffano et al. [8] the media were also identified as playing a limited role as a source of concussion information. however, social media are widely used among all ages and their role should be investigated in future research on concussion education. participants in the jahs group on average identified 62% of the cki questions correctly, while the sac group had an average of 60% (p=0.37). considering that 59% of the sac participants had previously received information about concussion, the percentage of informed participants seemed to be closely related to the mean percentage of correctly answered cki questions. however, this speculative relationship between information received and cki scores was not evident among the jahs group, who managed to obtain a mean of 62% of the cki answers correct, even though only 41% of them had previously received information on concussion. the most common misconception among participants in both groups was that a concussion could be identified via brain imaging, showing physical brain damage, which is in keeping with other studies.[1] considering that patients cannot refer themselves for brain imaging, the practical implication of this finding among rugby players may not be of major concern. however, the effect of this misconception on a player’s self-driven rtp decisionmaking is unknown and should be considered in future research. another apparent misconception is displayed in the mere 37% of jahs participants and 43% of sac participants who indicated that a concussion can be sustained via a hit anywhere on the body, and not only on the head. similar results have previously been reported, where only 47% of a study sample could correctly identify that head impact was not the only way to sustain a concussion.[1] this is a further motivation for education among rugby players to enable them to link preceding mechanisms of sustaining a concussion to the potential concussion symptoms displayed by teammates. among the jahs and sac participants, a headache was the most common correctly identified concussion symptom. in comparison, boffano et al.[8] reported headaches as the sixth most commonly identified concussion symptom. these authors reported symptoms of nausea, vomiting, memory loss, dizziness and loss of consciousness as symptoms more frequently identified by italian rugby players.[8] dizziness was also frequently identified correctly in the current study, with 84% of jahs participants and 71% of sac participants providing correct identification. in contrast to boffano et al. [8] the current study showed a low rate of correct identification of memory loss as a symptom of concussion; only 58% of sac participants could correctly identify this symptom. even though the jahs participants had better concussion knowledge, they displayed more unsafe attitudes or behaviours regarding concussion and rtp compared to the sac participants. in keeping with other health-related studies, such as knowledge of the risks of smoking which does not necessarily govern cessation habits,[13] the results from this study support other concussion studies, where the use of increased concussion knowledge as a predictor of the effectiveness of concussion educational tools has been criticised.[14] kroshus et al. argued that concussion knowledge only indicates if the individual paid attention to the information received, and not necessarily whether it is indicative of improved in-season reporting behaviours.[14] this view is echoed by kurowski et al. [15] who state that improved self-report behaviours were not associated with previous concussion education or better knowledge about concussion. in order to obtain effective behavioural change, kroshus et al.[14] propose adding real life simulation to educational programmes in order to help individuals make safe decisions. both the jahs and sac participants displayed unsafe attitudes to self-driven rtp approaches while concussed; only 55% of all participants reported that they would stop their participation in sport while experiencing concussion symptoms. this is alarming, considering that the majority of participants (jahs=82%, sac=77%) understood the potential risk of death when a second concussion is sustained while already concussed. this discrepancy could possibly indicate a misconception among players that the presence of some concussion symptoms does not necessarily constitute a diagnosis of being concussed. this conception should be investigated in future research. furthermore, this finding emphasises a need for concussion education among players in order to address possible misconceptions and promote safer attitudes/behaviours in concussion and rtp. increasingly unsafe attitudes/behaviours during playoff versus the first game of the season were seen among the sac participants. o’connell and molloy[12] found similar unsafe attitudes in their research, as 75% of their participants reported that they would continue to play with a concussion in important games. they further reported that players showed these unsafe behaviours as they did not want to let the team down. [1] certain limitations were identified during the course of the present study. sample size and selection were affected by the time of year data collection occurred, which resulted in fewer under-18 level players included in the jahs group due to the lack of scholars available for testing. a two-week period was given for data collection at school level, giving rise to the possibility of questionnaire content leaking, with original research sajsm vol. 29 2017 6 associated peer influence among scholar participants at different age levels. conclusion both junior and senior south african amateur rugby players displayed insufficient knowledge of concussion and unsafe attitudes/behaviours regarding concussion and rtp, with no statistically significant differences between their mean cki and the mean cai scores. unsafe attitudes were more evident during pressure situations, as participants showed higher unsafe responses towards rtp when playoff games were involved. this provides motivation for further implementation of concussion education programmes and their scope among amateur south african rugby players through the boksmart rugby safety programme. future research should focus on incorporating other geographical regions of south africa in order to improve generalisability of the findings, and implement population-specific concussion education programmes among all role players. the role of social factors in unsafe concussion attitudes/behaviours, despite the availability of information, should also be investigated for inclusion in concussion education programmes. conflict of interest: the authors have no conflict of interest to declare. no funding was received from any funding agencies in the public, commercial or non-profit sectors. references 1 carter m. the unknown risks of youth rugby. bmj 2015;350:h26. doi: 10.1136/bmj.h26 [pmid: 25566788] 2 kaux jf, julia m, delvaux f, et al. epidemiological review of injuries in rugby union. sports 2015;3:21-29.doi: 10.3390/sports3010021 3 harmon kg, drezner ja, gammons m, et al. american medical society for sports medicine position statement: concussion in sport. br j sports med 2013;47(1):15-26. doi: 10.1136/bjsports-2012-091941 [pmid: 23243113] 4 raftery m. concussion and chronic traumatic encephalopathy: international rugby board’s response. br j sports med 2014;48(2):79-80. doi: 10.1136/bjsports-2013093051 [pmid: 24096899] 5 gardner aj, iverson gl, williams wh, et al. a systematic review and meta-analysis of concussion in rugby union. sports med 2014;44(12):1717-1731. doi: 10.1007/s40279-014-0233-3 [pmid: 25138311] 6 boksmart. what is boksmart.. available from: http://boksmart.co.za/content/what-is-boksmart (accessed 15 august 2015). 7 sye g, sullivan sj, mccrory p. high school rugby players’ understanding of concussion and return to play guidelines. br j sports med 2006;40(12):1003-1005. doi: 10.1136/bjsm.2005.020511 [pmid:17124109] 8 boffano p, boffano m, gallesio c, et al. rugby players’ awareness of concussion. j craniofac surg 2011;22(6):20532056. 9 walker s. concussion knowledge and return-to-play attitudes among subelite rugby union players. s afr j sports med 2015;27(2):50-54. 10 williams j. concussion knowledge and attitudes in english football (soccer). master’s thesis. georgia, usa. georgia southern university; 2013. available from: electronic theses and dissertations (accessed 12 january 2015). 11 baker jf, devitt bm, green j, et al. concussion among under20 rugby union players in ireland: incidence, attitudes and knowledge. ir j med sci 2013;182(1):121–125. doi: 10.1007/s11845-012-0846-1 [pmid: 22898834] 12 o’connell e, molloy mg. concussion in rugby: knowledge and attitudes of players. ir j med sci 2016;185(2):521-528. doi: 10.1007/s11845-015-1313-6 [pmid:26026952] 13 xu x, liu l, sharma m, et al. smoking-related knowledge, attitudes, behaviours, smoking cessation idea and education level among young adult male smokers in chongqing, china. int j environ res public health 2015;12(2):2135-2149. doi:10.3390/ijerph120202135. 14 kroshus e, baugh cm, daneshvar dh, et al. concussion reporting intention: a valuable metric for predicting reporting behaviour and evaluating concussion education. clin j sport med 2015;25(3):243-247. doi: 10.1097/jsm.0000000000000137. 15 kurowski b, pomerantz wj, schaiper c, et al. factors that influence concussion knowledge and self-reported attitudes in high school athletes. j trauma acute care surg 2014;77(3 suppl 1):s12-s17. doi: 10.1097/ta.0000000000000316 [pmid: 25153048] http://dx.doi.org/10.3390/sports3010021 introduction peripheral arterial disease (pad) is characterised by the presence of atherosclerotic plaque in the peripheral arteries causing reduced blood flow to the peripheral limbs. reduced blood flow results in ischaemia. the pain of intermittent claudication is felt, particularly during exercise.1 the word ‘claudicare’ means to limp. typically the patient with pad will experience pain (either in the buttock, thigh or calf muscle) distal to the atherosclerotic obstruction. studies have shown that exercise training is an important and effective therapy for patients with pad. the effects of exercise training on pad and intermittent claudication have been reviewed.2 typically exercise programmes continue for 6 weeks to 6 months and vary in the mode of exercise training used. in a meta-analysis by gardner et al.18 of 21 studies on exercise training in patients with pad, pfwd increased 179% and the mwd increased 122% following exercise training.18 despite the clear evidence of patients clinically benefiting from exercise training, the mechanism(s) of the training response remains unclear. several mechanisms have been proposed and researched and these will be discussed in this paper. improvements in blood flow – increased collateral circulation and increased endothelium-dependent dilation skinner and strandness3 claimed that exercise training increased collateral circulation to the ischaemic muscle. they found a reduction in the post-exercise hyperaemic response with exercise training.3 postexercise hyperaemia is when blood flow increases to the ischaemic muscle after exercise, and as a result blood flow decreases to the foot, causing a reduction in ankle pressure. the greater the reduction in ankle pressure, the greater the extent of the underlying peripheral arterial disease as blood is shunted to the ischaemic muscle.19 therefore the authors argued that because this post-exercise hyperaemic response was dampened by exercise training, exercise training must improve blood flow to the ischaemic limb and stated that this was through collateral growth (although they did not prove this). in that same period, alpert et al.4 documented that exercise training increased absolute blood flow to the lower limbs (measured by the 133xe clearance method) and also attributed this to the development of a collateral circulation.4 twenty years later a study by carter et al.5 also found that systolic ankle pressure recovery to normal levels following the post-exercise hyperaemic response was more rapid after a period of exercise training. furthermore, an increase in walking tolerance was related to a decrease in the time of the ankle pressure to return to pre-exercise levels but not to any other haemodynamic variables (absolute ankle pressure and abi),5 and therefore the development of an increased collateral circulation and improved blood flow was unlikely. in support of this study, jonason and ringqvist6 found that post-exercise ankle pressure (from minute 2 16) was higher after a period of exercise training. however, there was no change in calf blood flow at rest or post-ischaemic maximum blood flow measured by strain gauge plethysmography. they attributed this reduction in post-exercise hyperaemia to ‘a more optimal distribution and utilization of available blood flow with exercise training’.6 therefore neither carter et al.5 or jonason and ringqvist6 could attribute increased walking tolerance following exercise training to increased blood flow to the lower limb through an increased collateral circulation. subsequently two more studies have shown that blood flow to the lower limb as measured by strain gauge plethysmography increases with exercise training.7,8 however, neither of the above mechanisms of the training response in patients with peripheral arterial disease – a review abstract exercise training has proved to be a beneficial treatment for patients with peripheral arterial disease (pad) suffering from the symptom of intermittent claudication. the mechanism by which symptomatic improvement occurs is unclear. the review summarises the mechanism of the training response in patients with pad, focusing on improvements in bloodflow as well as biochemical, muscle recruitment and psychological adaptations. possible areas of future research are suggested. correspondence: yumna albertus uct/mrc research unit for exercise science and sports medicine sports science institute of south africa po box 115 newlands, 7725 phone: +27 21 650 4567 fax: +27 21 686 7530 e-mail: yumna.albertus@uct.ac.za b parr (msc)1 y albertus-kajee (phd)2 e w derman (mb chb, phd, facsm, ffims)2 1cape peninsula university of technology 2uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town and sports science institute of south africa clinical review 26 sajsm vol 23 no. 1 2011 studies proved that improvement in blood flow is due to an increased collateral circulation. more recently a study in subjects with mild hypertension found that after 12 weeks of exercise training, forearm blood flow increased significantly in response to acetylcholine (an endothelium-dependent vasodilator) but not to isosorbide dinitrate (an endotheliumindependent vasodilator) in the exercise group but not in the control group.20 studies using the elderly 21,22 or patients with coronary artery disease23 and on animals with chronic coronary occlusion24 have revealed that exercise training improves endotheliumdependent vasorelaxation through an increase in the release of nitric oxide. endothelial cells release nitric oxide, a lipid-soluble gas, in response to the stimulus of increased blood flow through the vessel lumen (as would happen during exercise).25 indeed, it is apparent that a depressed endothelial function is more likely to improve with exercise training than in patients with normal endothelial function (i.e. in the young and healthy).26 sajsm vol 23 no. 1 2011 27 table i. review of the trials determining the mechanism of the training response in patients with pad authors proposed mechanism of response effect of exercise training variable measured skinner and strandness 3 increase in collateral circulation the decrease in ap with exercise was less after training ankle pressure alpert et al.4 increase in collateral circulation increased absolute blood flow to lower limb blood flow (133xe clearance method) carter et al. 5 redistribution of blood flow, increased capacity of skeletal muscles time for post-exercise ankle pressure to reach normal levels after exercise was less. no change in abi or ap systolic ap recovery abi ap absolute jonason and ringqvist 6 more optimal distrib and utilisation of available blood flow with exercise training post-exercise ap was higher 2-16 minutes after exercise ap blood flow (strain gauge plethysmography) hiatt et al. 7 increase in blood flow increase in blood flow blood flow (strain gauge plethysmography) gardner et al.8 increase blood flow increase in blood flow blood flow (strain gauge plethysmography) brendle et al.9 increase in endothelial-dependent dilation 60% improvement in flow mediated brachial artery diameter and resting artery diameter brachial artery diameter and flow velocity measured by an ultrasound system lundgren et al. 10 oxidative enzyme activity increases with physical activity cytochrome-c oxidase (cyt-ox) activity increased with training biopsies of calf muscle tissue, cyt-ox activity measured holm et al.11 restricted oxygen supply during exercise increases oxidative enzymes activity mitochondrial succinic oxidase increases with training. increased blood flow with training but not correlated to mwd biopsies of lateral vastus muscle and medial head of gastrocnemius muscle ap abi sorlie and myhre 12 increased oxygen extraction by skeletal muscles venous oxygen saturation was lower at exhaustion after training than before. max lactate concentration lower after physical training catheter into distal femoral vein and brachial artery zetterquist 13 increased oxygen extraction by the skeletal muscles attributed to a regional redistribution of available blood flow towards active muscles o2 saturation of femoral venous blood was significantly lower after training at identical loads catheter into femoral vein of affected leg hiatt et al. 14 improved skeletal oxidative metabolism decrease in resting plasma shortchain acylcarnatine concentration blood samples taken and carnatine measured by radioenzymatic assay parr et al. 15 mechanism unclear venous lactate concentrations low at maximal exercise capacity and not correlated to walking distances blood samples from brachial artery ruell et al.16 lower lactate concentrations after physical training venous lactate concentrations lower at submax and at exhaustion blood samples taken from brachial artery walking distances pedrinelli et al. 17 central drive increases following a supervised walking programme raised initial mdf but not to normal values after the walking programme muscle fibre conduction velocity and median frequency of tibialis anterior muscle gardner et al. 18 improved pain tolerance through exposure to pain claudication pain end point used during training was the most important predictor of change in pfwd meta-analysis of controlled trials ap = ankle pressure; abi = ankle brachial index; cyt-ox = cytochrome-c oxidase; mdf = median frequency; mwd= mean walking distance; pfwd= pain-free walking distance. it has been shown in patients with pad that endotheliumdependent dilation is impaired or depressed. this was shown by measuring maximum brachial artery diameter and flow after brachial artery occlusion (with a blood pressure cuff) in patients with pad and controls.27 only one study has shown that exercise rehabilitation improves endothelial-dependent dilation in older patients with pad.9 this study found a 60% improvement in the flow-mediated brachial arterial diameter as well as in the resting arterial diameter. however, this study was not randomised or controlled. it is perhaps the improved endothelial-dependent vasodilation that is responsible for improvements in walking tolerance and blood flow. it is possible that improved endothelial-dependent vasodilation in patients with pad as a result of exercise training allows for a less pronounced and shorter duration post-exercise hyperaemic response and decrease in ankle pressure after a bout of exercise, which would explain the findings of the studies completed in the 1960s and 1980s. finally, it may not only be the endothelium that is responsible for vasodilation in patients with pad. further examination is also required of the ability of the smooth-muscle cells of the arteries to cause vasodilation in response to adenosine in patients with pad. a study by hambrecht et al.23 found that coronary blood flow reserve (the ratio of the mean peak flow velocity to the resting velocity after adenosine infusion) increased significantly after 4 weeks of training in patients with coronary artery disease.23 future research should examine this response to exercise training in patients with pad. biochemical adaptations in skeletal muscle in patients with pad following exercise training because patients with pad have reduced blood flow to the exercising limb(s), it has been suggested that anaerobic glycolysis resulting from ischaemia increases the lactate concentration in the skeletal muscles and blood, which leads to claudication pain.27,10 this was summarised in a review article by tan et al.,28 who stated, ‘in patients with peripheral vascular disease, increasing the workload causes an inequality in the supply of and demand for oxygen. aerobic generation of atp becomes inadequate and anaerobic metabolism predominates. the result is an increase in lactic acid production, and a depletion of atp and creatine phosphate, leading to pain.’ support for this theory is found in studies that have shown that improvements in walking tolerance following exercise training in patients with pad occur alongside increases in the number of oxidative enzymes found in the skeletal muscle,11,10 improvements in oxygen extraction by the skeletal muscles12,29 and a decrease in the concentration of acylcarnatines16 (produced during skeletal muscle ischaemia). the theory is that these adaptations delay the onset of anaerobic glycolyis, lactate accumulation and pain. this theory of walking intolerance in patients with pad stems from the popular cardiovascular/anaerobic theory of fatigue which suggests that fatigue develops when the exercising skeletal muscles fail to get enough oxygen to them and as a result have to rely on anaerobic glycolysis to produce enough atp to continue exercising.30 a by-product of anaerobic glycolysis is lactate accumulation in the skeletal muscles and blood. a recent study in this laboratory found that although venous lactate concentrations increased following a graded treadmill exercise test, the values were very low (2.08±1.6 to 3.28±1.39 mmol.l-1) and furthermore did not correlate to pfwd or mwd in patients with pad.15 others have found that venous and arterial lactate concentrations were higher in patients with pad at maximal exercise capacity than in age-matched controls at maximal exercise capacity29 and lower after surgical reconstruction or physical training in these patients.29,16 however, concentrations of blood lactate never reached higher than 4 mmol.l-1 in these studies. values in a normal population at maximal exercise capacity reach far greater values than this (7.59 mmol.l-1) and the subjects never experience claudication.31,32 in skeletal muscle, there was no significant difference in lactate concentration values between patients with pad and controls at maximal exercise capacity.16 therefore, the suggestion that accumulation of lactate in the skeletal muscles and blood leads to claudication pain, is unlikely. there has to be some other mechanism for the pain that patients with pad experience. muscle recruitment response to claudication and exercise training recently it has been suggested that fatigue in the normal population develops when muscle recruitment is reduced by the motor cortex, causing exercise to terminate. this happens because inhibitory reflexes arise from the exercising muscles and feedback to the spinal cord and motor cortex, reducing skeletal muscle recruitment. this theory has been previously reviewed.33,34 the influence of the central nervous system on muscle recruitment is commonly measured using surface electromyography (emg). emg comprises of the sum of electrical contributions made by the active motor units which are detected by electrodes placed on the skin surface overlying the muscle.35 few studies have investigated muscle activity in patients with pad after interventions including exercise training response and percutaneous transluminal angioplasty (pta). the only published studies investigating emg in these patients have studied changes in median frequency (mdf, the frequency value which divides the power density spectrum of emg signal into two equal halves), nerve conduction velocity of peroneal and tibial nerves 36,37,33,17 and a recent case study investigating changes in emg after angioplasty.38 a study conducted by pedrinelli et al.17 examined muscle fibre conduction velocity (mfcv) and mdf of the tibialis anterior muscle during tetanic electrical stimulations in patients with pad and controls. mfcv ranges did not differ significantly between patients and healthy controls. however, mdf of both the ischaemic and non-ischaemic legs were found to be significantly lower than the controls, as the healthy limb also showed a decrease in mdf. this finding suggests that chronic ischaemia was not the cause of lower mdf in patients with pad. it is of interest to note that this study used a 3-week walking programme intervention, which resulted in improved exercise tolerance, raised initial mdf but not to normal values after the walking programme; and unchanged mfcv in patients with pad. these findings suggest that central drive increases following a supervised walking programme and factors other than ischaemia and physical inactivity underlie the abnormal emg signal in patients with pad. a case study conducted by albertus-kajee et al.38 on a patient with pad came to similar conclusions, where muscle activity in the diseased leg was found to increase after angioplasty. they explain this increase in emg as a possible increase in central drive to the lower limbs after angioplasty, which resulted in an increase in functional capacity. interestingly, the blood lactate concentrations were low ranging between 2.00 and 1.75 mmol.l-1 before angioplasty and 1.75 1.50 mmol.l-1 after angioplasty. the influence of muscle recruitment on the training response in these patients is therefore of special interest and needs to be further investigated. although the use of emg in the evaluation of this disease is still in early development, it provides a non-invasive assessment and understanding of the physiopathology of skeletal muscle involvement in patients with pad. 28 sajsm vol 23 no. 1 2011 sajsm vol 23 no. 1 2011 29 psychological adaptations to exercise training some of the improvement in exercise tolerance noted with exercise training in patients with intermittent claudication may be attributed to psychological factors. this was made apparent in a review where a number of important predictors of the outcome of an exercise programme were identified.39 the best correlation with good outcome of the exercise programme was belief that the exercise would lead to an improvement in walking status. moreover, patients can be influenced by the level of motivation they feel on the particular day of testing. this was made apparent in a study which noted: ‘the psychology involved when walking with pain was highlighted by the two-thirds of patients who said they could walk no further but then immediately walked 15 45 m to the rest room’.40 lastly it seems that as patients subject themselves to pain, their pain tolerance improves. gardner et al.18 found in a meta-analysis that claudication pain end-point used during an exercise training programme was the most important independently related predictor of the positive change in pfwd distance and mwd in patients with intermittent claudication.18 the longer patients ‘walked into’ their pain during training, the more pfwd and mwd improved after training. therefore, factors including the belief that the exercise training will work, motivation to walk and improvements in pain tolerance can affect walking tolerance. if it is true that the motor cortex reduces muscle recruitment in response to pain then these psychological factors could perhaps act against central regulation, allowing for the patient to train longer and eliciting better functional results. this is an area of future research. conclusion early research attributed improvements in walking distances with exercise training to improvements in collateral circulation or peripheral adaptations in the exercising skeletal muscles. this review indicates that endothelium-dependent dilation improves with exercise training and should be researched further in controlled, randomised trials. moreover, the possibility that the central 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2004;96:1486-1495. 36. argyriou aa, tsolakis i, papadoulas s, polychronopoulos p, gourzis p, chroni e. dynamic f wave study in patients suffering from peripheral arterial occlusive disease. acta neurol scand 2007;115:84-89. 37. mcdermott mm, guralnik jm, albay m, bandinelli s, miniati b, ferrucci l. impairments of muscles and nerves associated with peripheral arterial disease and their relationship with lower extremity functioning: the inchianti study. j am geriatr soc 2004;52:405-410. 38. albertus y, swart j, lamberts r, lambert mi, noakes td, derman ew. alteration in emg during graded treadmill exercise test after 3 days recovery from angioplasty in a patient with peripheral vascular disease. int sports med j 2011. in print 39. rosfers a, arnetz bb, bygdeman s, skoldo l, lahnborg g, eneroth p. important predictors of the outcome of physical training in patients with intermittent claudication. scan j rehab med 1990;22:135-137. 40. watson cje, phillips d, hands l, collin j. claudication distance is poorly estimated and inappropriately measured. brit j surg 1997;84:1107-1109. sajsm 377.indd original research sajsm vol. 25 no. 3 2013 81 background. the abdominal musculature plays a protective role against lower-back injury. knowledge of the asymmetry in abdominal wall thickness in healthy, injury-free cricket pace bowlers may provide a useful platform against which pathology could be assessed and the effects of training could be evaluated. objective. to compare side-to-side differences in absolute muscle thickness and activity of the abdominal musculature and to compare these measurements at the start, with those at the end of a cricket season among a group of amateur pace bowlers. methods. this was a controlled longitudinal prospective study. rehabilitative ultrasound imaging was used to assess abdominal muscle thickness in 26 right-handed, injury-free cricket pace bowlers at the start and at the end of a cricket season. thickness measurements were done at rest, during an abdominal drawing-in manoeuvre (adim) and the active straight-leg raise (aslr) on the left (-l) and right (-r). results. the absolute thickness of the non-dominant obliquus abdominis internus (oi) was higher than that of the dominant oi at the start (p=0.001; es=0.87) as well as at the end of the cricket season (p=0.001; es 1.09). at the start of the season, the percentage change during the adim, thus muscle activity, was higher for the non-dominant oi than for the dominant oi (p=0.02; es=0.51). absolute thickness of the dominant obliquus abdominis externus (oe) at rest was significantly higher at the end of the season compared with the start of the season (p=0.0001; es=0.85). during aslr-r, the activity of the left transversus abdominis (ta) was significantly higher than that of the right ta during aslr-l (p=0.03) when measured at the end of the season. conclusion. this study highlights the possible muscle adaptations in absolute muscle thickness and activity as a consequence of the asymmetrical bowling action. s afr j sm 2013;25(3):81-86. doi:10.7196/sajsm.377 side-to-side asymmetry in absolute and relative muscle thickness of the lateral abdominal wall in cricket pace bowlers b olivier,1 pt, msc; a v stewart,1 pt, phd; w mckinon,2 phd 1 school of therapeutic sciences, department of physiotherapy, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 school of physiology, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: b olivier (benita.olivier@wits.ac.za) lower-back injury is one of the most common types of injury sustained by cricket pace bowlers.[1] the abdominal musculature plays a protective role against such injury by increasing the stability of the lumbar segmental vertebrae.[2] the assessment of thickness of the abdominal muscles including transversus abdominis (ta), obliquus abdominis internus (oi) and oblique abdominis externus (oe) is known to be a valid measure of size of the abdominal muscles, as well as a sensitive measure of change. ferreira et al.[3] found that ta and oi percentage change in thickness are valid measures of activity compared with electromyography (emg). rehabilitative ultrasound imaging (rusi) is often used as a surrogate measure for activation of the abdominal muscles. muscle thickness, as measured by rehabilitative ultrasound imaging (rusi), is well correlated with muscle thickness measurements derived from magnetic resonance imaging (mri).[4] mannion et al.[5] and springer et al.[6] conducted abdominal muscle activation studies in non-sporting populations and showed that there were no differences in activation between body sides. rankin et al.[7] also found no statistically significant differences in muscle thickness between the left and right oi and oe when measured at rest, but a difference in ta was found where the left ta was thicker than the right in moderately active individuals. they did not specify whether the recreational activities were mainly symmetrical or asymmetrical. in contrast to the findings of the aforementioned authors,[5-7] hides et al.[8] found that the oi on the non-dominant side of elite cricketers was thicker than on the dominant side. hides et al.[8] assessed a small sample size of elite cricketers, including batsmen and bowlers. it was suggested that the asymmetrical demands of the repetitive bowling action may cause some muscles to be activated preferentially and hypertrophied above other muscles.[8] knowledge of the asymmetry in abdominal wall thickness in healthy and injury-free cricket pace bowlers may provide a useful platform against which aetiology of injury could be assessed and training could be gauged, and could provide a benchmark to direct rusi biofeedback interventions in the future. the aim of this study was to compare side-to-side differences in absolute muscle thickness and muscle activation of the abdominal musculature, and to compare absolute muscle thickness and muscle activation measured at the start v. the end of a cricket season in a group of amateur fast, fast-medium and medium pace bowlers. methods ethics ethical clearance was granted by the human research ethics committee of the university of the witwatersrand (reference m10430). all 82 sajsm vol. 25 no. 3 2013 participants signed informed consent and had the right to withdraw from the study without suffering any repercussions. participants twenty-six right-handed, premier league (amateur) cricket pace bowlers were invited to participate in the study on condition that they were free of injury. participants were tested at the start and again at the end of an 8-month cricket season. validity and reliability the criterion-related validity of rusi to measure muscle thickness has been established against mri.[4] a strong linear relationship is also known to exist between abdominal muscle thickness change (ta and oi) and emg amplitude during low levels of muscle contraction (up to 30% of maximum voluntary contraction). no consistent relationship was found between oe thickness change and muscle contraction; therefore, this should not be used to detect muscle activity.[3] intrarater reliability was established by springer et al.[6] as being between 0.93 (95% ci 0.86 0.96) and 0.99 (95% ci 0.98 1.00), as well as by rankin et al.[7] as being 0.98 0.99 (95% ci 0.91 1.00). procedures abdominal muscle thickness was measured using a dp-6600 digital ultrasonic imaging system (shenzhen mindray bio-medical electronics, china) with a 5 mhz curvilinear transducer with a large footprint (≥60 mm). the first author underwent training in the use of the equipment and performed all measurements. rusi was done in brightness (b) mode. the ultrasound echo was recorded as a crosssectional gray-scale image.[9] each participant was positioned in supine with their legs straight. the transducer was placed along the lateral abdominal wall along the mid-axillary line, midway between the inferior angle of the rib cage (lower border of the 11th costal cartilage) and the iliac crest in the transverse plane.[9] the medial edge of the ta muscle was positioned at the medial edge of the ultrasound image.[9] this is the most appropriate position as all three muscles are well represented and relatively flat and easy to measure on the image.[7] all images were taken on the left and the right with the participant at rest at the end of relaxed expiration with the glottis open to avoid bracing. [9] the participants were then instructed to perform the abdominal drawing-in manoeuvre (adim) by exhaling and gently drawing their lower abdomen towards the spine,[10] using 20% of the maximal voluntary contraction. the following standardised instructions were given to each participant: ‘take a relaxed breath in and out, hold the breath out and then draw in your lower abdomen without moving your spine.’ participants had the opportunity to practice the adim five times before measurements were taken. after performing the adim, the participants were instructed to relax their abdominal muscles completely. during the active straight-leg raise (aslr), the bowler had to lift his leg 5 cm from the plinth.[9,11] aslr was performed on the left (-l) and right (-r). the transducer position was kept constant during all of the above.[9] the research assistant verified proper execution of the adim and aslr and recorded the frame number of each image. the thickness of ta, oi and oe was measured (in mm) on each of the following images: at rest, adim, aslr-l and aslr-r. the distance between the superior and inferior hyperechoic muscle fascias of the ta, oi and oe was measured in the centre of the muscle belly by using a vertical straight table 1. absolute thickness at rest and percentage change* in thickness in adim, aslr-l and aslr-r activity positions of the dominant v. non-dominant ta, oi and oe† pre-season (n=26) post-season (n=26) nondominant mean (±sd) dominant mean (±sd) p-value effect size cohen’s d nondominant mean (±sd) dominant mean (±sd) p-value effect size cohen’s d ta rest (mm) 4.6 (±1.4) 4.9 (±1.4) 0.25 0.17 4.9 (±1.4) 5.3 (±1.4) 0.10 0.35 adim % change 56.5 (±47.7) 41.9 (±31.2) 0.09 0.37 41.6 (±34.8) 27.0 (±27.1) 0.19 0.48 aslr-l % change 17.4 (±34.2) 14.1 (±30.8) 0.66 0.10 15.8 (±25.6) 5.7 (±21.9) 0.16 0.44 aslr-r % change 25.4 (±35.5) 16.5 (±26.3) 0.22 0.29 20.2 (±35.2) 5.5 (±20.8) 0.05 0.52 oi rest (mm) 14.2 (±4.1) 11.4 (±2.4) 0.00† 0.87 15.2 (±3.4) 11.9 (±2.7) 0.00† 1.09 adim % change 13.0 (±20.2) 2.7 (±21.6) 0.02† 0.51 11.1 (±15.5) 7.6 (±13.5) 0.37 0.24 aslr-l % change 9.8 (±27.7) 1.5 (±20.1) 0.19 0.35 14.1 (±19.3) 7.7 (±21.5) 0.14 0.32 aslr-r % change 8.6 (±21.4) 5.7 (±20.6) 0.58 0.14 4.0 (±24.0) 8.9 (±19.8) 0.40 0.23 oe rest (mm) 6.4 (±2.3) 6.0 (±1.4) 0.33 0.25 7.4 (±2.6) 7.5 (±2.1) 0.76 0.05 ta = transversus abdominis; oi = oblique abdominis internus; oe = oblique abdominis externus; adim = abdominal drawing-in manoeuvre; aslr-l = active straight-leg raise (left); aslr-r = active straight-leg raise (right); sd = standard deviation. * percentage change was calculated as a percentage of muscle thickness at rest: (muscle activated muscle at rest) ÷ muscle at rest × 100. † significant difference between dominant and non-dominant sides (p<0.05). sajsm vol. 25 no. 3 2013 83 line through the middle of the image. measurements were conducted perpendicular to the muscle fascia. [10,11] data analysis statistical analysis was conducted using statistica (version 10). thickness was reported as absolute muscle thickness at rest (ta, oi and oe) and thickness percentage change or muscle activity (ta and oi). thickness percentage change was calculated as muscle thickness during activity as a ratio to muscle thickness at rest: muscle thickness in contracted state minus muscle thickness at rest, divided by muscle thickness at rest multiplied by 100.[10,11] absolute thickness as well as thickness change on the dominant and non-dominant sides were compared using the paired student’s t-test. likewise, the absolute thickness and thickness change recorded at the start of the cricket season were compared to thickness measurements at the end of the cricket season using the paired student’s t-test.[7] statistical significance was set at p<0.05. effect sizes were calculated using cohen’s d where effect sizes of 0.2, 0.5 and 0.8 were interpreted as small, medium and large, respectively. results twenty-six healthy, male, right-handed, fast, fast-medium and medium pace bowlers aged 18 26 years participated in the study (mean age 21.8 years, standard deviation (sd) ±1.8). most had more than 6 years’ experience as a pace bowler, with the exception of two who each had 5 years’ experience. the absolute thickness of the non-dominant oi at rest was higher than that of the dominant oi (table 1), with large effect sizes found for pre(es=0.87) and post-season (es=1.09) measurements (p=0.001). no side-to-side difference was found in absolute muscle thickness at rest for ta (p=0.25 and p=0.10) and oe (p=0.33 and p=0.76) at the start or end of the season, respectively. at the start of the season the percentage change during the adim, thus muscle activity, was higher for the non-dominant oi than for the dominant oi (p=0.02; es=0.51). this was not the case when looking at post-season oi activation during adim (p=0.37). absolute thickness of the dominant oe at rest was significantly higher at the end of the season compared with at the start of the season (p=0.001; es=0.85), while no difference was found in ta (p=0.07) and oi (p=0.28) thickness (table 2). furthermore, no difference was found in recruitment of the dominant and non-dominant ta and oi in adim (p=0.07 0.75), aslr-l (p=0.07 0.88) and aslr-r (p=0.06 0.67) activity positions at the start compared with the end of the cricket season. during aslr-r, the activity of the left ta was significantly higher than that of the right ta during aslr-l (p=0.03) at the end of the season (fig. 1c). the same was true for ta during the aslr-l (p=0.17) at the start of the season (fig. 1a). during ipsilateral muscle activity in aslr-l and aslr-r, the activation of the left ta was higher than that of the right ta (pre-season: p=0.79; post-season: p=0.15). discussion we investigated the absolute thickness of ta, oi and oe at rest as well as ta and oi activity in adim, aslr-l and aslr-r activity at the start and end of a cricket season. in our study, oi was the thickest muscle and ta the thinnest, which is similar to the findings of mannion et al.[5] and rankin et al.[7] the absolute muscle thickness of ta (4.6 5.3 cm) was slightly greater than that found by mannion et al.[5] (3.9 4.0 cm), while the oi values (11.3 15.2 cm) in the present study were much higher table 2. absolute thickness at rest and percentage change* in thickness in adim, aslr-l and aslr-r activity positions of ta, oi and oe at the start v. the end of a cricket season (n=24)† non-dominant dominant pre-season mean (±sd) post-season mean (±sd) p-value effect size cohen’s d pre-season mean (±sd) post-season mean (±sd) p-value effect size cohen’s d ta rest (mm) 4.6 (±1.1) 4.9 (±1.4) 0.13 0.22 4.9 (±1.3) 5.3 (±1.4) 0.07 0.38 adim % change 55.8 (±46.2) 41.6 (±34.8) 0.13 0.35 41.7 (±32.3) 27.0 (±27.1) 0.07 0.51 aslr-l % change 17.0 (±35.4) 15.8 (±26.6) 0.88 0.04 13.1 (±31.7) 5.7 (±21.9) 0.35 0.28 aslr-r % change 23.8 (±34.8) 20.2 (±35.2) 0.67 0.11 16.7 (±27.3) 5.5 (±20.8) 0.06 0.47 oi rest (mm) 14.1 (±3.9) 15.2 (±3.4) 0.12 0.32 11.3 (±2.3) 11.9 (±2.7) 0.28 0.24 adim % change 12.6 (±20.4) 11.1 (±15.5) 0.75 0.08 2.0 (±22.1) 7.6 (±13.5) 0.25 0.31 aslr-l % change 9.7 (±28.34) 14.1 (±19.3) 0.48 0.19 0.03 (±20.2) 7.7 (±21.5) 0.07 0.38 aslr-r % change 8.7 (±20.7) 4.0 (±24.0) 0.45 0.21 4.7 (±18.6) 8.9 (±19.8) 0.41 0.22 oe rest (mm) 6.5 (±2.3) 7.4 (±2.6) 0.12 0.35 6.0 (1.4) 7.5 (±2.1) 0.00† 0.85 ta = transversus abdominis; oi = oblique abdominis internus; oe = oblique abdominis externus; adim = abdominal drawing-in manoeuvre; aslr-l = active straight-leg raise (left); aslr-r = active straight-leg raise (right); sd = standard deviation. * percentage change was calculated as a percentage of muscle thickness at rest: (muscle activated muscle at rest) ÷ muscle at rest × 100. † significant differences between preand post-season (p<0.05). 84 sajsm vol. 25 no. 3 2013 and the oe values (6.0 7.5 cm) correspond closely to those found by mannion et al. (oi: 8.3 8.6 cm; oe: 6.7 7.1 cm). mannion et al.[5] used a non-sporting population consisting of volunteers and this may explain their participants’ lesser ta and oi thickness values. in contrast, rankin et al.[7] found a mean ta thickness (4.5 5.1 cm) similar to what was found in the present study, with thinner oi (11.7 11.8 cm) and thicker oe muscles (9.6 9.7 cm) in moderately active volunteers. [7] although hides et al.[8] did not measure oe thickness, they found higher thickness values for both ta (6.8 7.2 cm) and oi (16.7 16.8 cm) than in this study. the professional fast bowlers assessed in the latter study were likely to be able to devote more time to pace-bowling training and conditioning, which may lead to greater hypertrophy of the abdominal musculature than in elite players. these differences in oi absolute thickness suggest that the more active the population, the larger the oi values, and might indicate the particular activation of oi muscles during high load, repeated, asymmetrical physical activity. a similar trend was found in resting thickness for ta, but not for oe. it would appear that as the oi gets thicker, the oe gets thinner, thus the relative balance in resting muscle thickness changes as the activity of the individual changes. this hypothesis requires further study; however, the consistent methods used by the latter studies[5,7,8] might suggest that different abdominal muscles display far more complex responses to training than was previously thought. in the current study, the absolute thickness of the oi at rest was significantly higher on the non-dominant side than on the dominant side, both at the start as well as at the end of the cricket season as shown in table 1. the large effect sizes emphasise the significance of this finding. in contrast to the findings in our study, mannion et al.[5] and springer et al.[6] found no statistically significant differences between the left and right abdominal muscle thickness and rankin et al.[7] found asymmetries in ta thickness only. in the case of springer et al.[6] and mannion et al.,[5] the researchers used a sample where no or few participants engaged in unilateral or rotational sporting activities. springer et al.[6] suggest that individuals who routinely participate in rotational activities such as tennis and golf may be more likely to display asymmetries. asymmetrical findings may increase the risk of developing pathology.[1] however, in a mathematical model used to estimate lumbar spinal stresses during quadratus lumborum muscle asymmetry, it was suggested that quadratus lumborum muscle asymmetry only causes small stresses and it may even help to reduce stress on the lumbar spine.[12] participants in this study were all healthy, pain and injury-free at the time of testing, which may suggest that factors other than pathology are responsible for the asymmetries found, as suggested by de visser et al.[12] these differences in absolute muscle thickness on the non-dominant and dominant sides may be as a result of long-term preferential use of the right bowling arm and subsequent preferential, asymmetrical recruitment of abdominal muscle fibres that may play a role in protection of the lumbar spine. it should, however, be noted that the asymmetries seen in pace bowlers are one of the factors predisposing them to their known susceptibility to lower-back injury,[1] 25 20 15 10 5 0 ta oi 13.1 23.8 0 8.7 right abdominal muscles (aslr-l) left abdominal muscles (aslr-r) a 25 20 15 10 5 0 right abdominal muscles (aslr-l) left abdominal muscles (aslr-r) 20.2 5.7 7.7 4 ta oi c ta oi right abdominal muscles (aslr-r) left abdominal muscles (aslr-l) 17 16.7 9.7 4.7 18 16 14 12 10 8 6 4 2 0 b ta oi 15.8 5.5 14.1 8.9 18 16 14 12 10 8 6 4 2 0 right abdominal muscles (aslr-r) left abdominal muscles (aslr-l) d fig. 1. percentage change in thickness measured in the aslr-l (non-dominant) and aslr-r (dominant) activity positions: (a) pre-season in contra-lateral muscles (ta: p=0.17; oi: p=0.13); (b) pre-season in ipsilateral muscles (ta: p=0.79; oi: p=0.48); (c) post-season in contra-lateral muscles (ta: p=0.03; oi: p=0.50); (d) post-season in ipsilateral muscles (ta: p=0.15; oi: p=0.31). sajsm vol. 25 no. 3 2013 85 but this asymmetry may also play a protective role.[12] taking the biomechanics of the pace-bowling action into account (fig. 2), weight is put onto the non-dominant leg at front-foot placement when the ground reaction force is extremely high,[13] which may mean that the ipsilateral oi has to contract to assist in absorbing the ground reaction forces, taking into account the position of the pace bowler. in the present study, the absolute thickness of the non-dominant oi was greater than that of the dominant oi, which fits with the above theory. also, while the non-dominant leg takes a vast amount of the load during the delivery stride, the dominant oe contracts in order to stabilise the pelvis in its typical cross-over activation fashion.[14] the repetitive nature of a pace bowler’s role in cricket training and in competition, resulting in many replicates of the bowling action, may explain the greater oe absolute thickness values found in this study at the end of the cricket season in comparison with the start of the cricket season (table 2). although this may explain the difference in absolute muscle thickness of the oi and oe at rest, it must be noted that activation levels between the non-dominant and dominant oi in asymmetrical aslr-l and aslr-r activity positions were not statistically significant. during a symmetrical activity position (adim), the activation of the non-dominant oi is greater than that of the dominant side. although this finding is only statistically significant for the pre-season measurements on oi, all other activation findings for oi and ta during the adim show that the abdominal muscles on the non-dominant side are activated at a higher rate than the dominant abdominal muscles. this may emphasise the repeated utilisation of the non-dominant ta and oi during the bowling action, and the subsequent preferential recruitment. the asymmetry of the bowling action may play a role in the development of habitual movement patterns maintained by pre-programmed motor-control pathways. [15] furthermore, the activation of ta is higher than the activation of oi in the adim, aslr-l and aslr-r activity positions, which indicates that the ta is the preferential muscle recruited during sub-maximal muscle contraction.[10] during asymmetrical activity positions, the left ta showed statistically significantly greater activity during the aslr-r than the right ta during aslr-l (fig. 1). this was also clear during the aslr-l, where the left ta activity was again much higher than the right ta activity during aslr-r; although not statistically significant, it is of clinical significance. this finding indicates that the left ta activity is higher than the right ta activity during contra-lateral as well as ipsilateral activity positions. this is contradictory to a study by teyhen et al.[11] which found that the ta is symmetrically activated during asymmetrical activity, while hu et al.[14] found that ta and oi showed greater asymmetrical activity than oe. the difference in results can be attributed to the different populations studied, where teyhen et al.[11] studied department of defence healthcare beneficiaries, including active-duty military family members and retirees, and hu et al.[14] studied a group of females. neither author specified details on specific sports participation. the difference in dominant and non-dominant ta activity is less pronounced during the pre-season measurements, which again shows that the intense training and repetition of the asymmetrical bowling action that takes place during a cricket season may be responsible for the preferential increase in activation of non-dominant ta. study limitations no comparison group of non-athletes was assessed in parallel to the pace bowlers in this study. generalisation of the current findings is thus limited to cricket pace bowlers and future studies should be performed to run-up the bowler walks or jogs, gradually increasing his speed, as he approaches the wicket. the run-up ends as he leaps into the air at the start of the pre-delivery stride. the run-up length varies between 15 m and 30 m. pre-delivery stride the bowler jumps o� his left foot and lands on the right or back foot. the shoulders are pointing down the wicket. delivery stride the bowler lands on his back foot with the body leaning away from the batsman. the delivery stride includes back-foot strike, frontfoot strike and ball release. follow-through the bowling arm follows through down the outside of the left thigh. fig. 2. the phases of the pace bowling action (reference made to a right-handed bowler). 86 sajsm vol. 25 no. 3 2013 compare abdominal muscle absolute thickness and activity in different sporting populations. furthermore, studies should be done to assess the training components of the cricket season, the activation of the abdominal muscles during the pace-bowling action and its influence on abdominal muscle thickness. conclusion our study highlights the possible muscle adaptations in absolute muscle thickness and activity as a consequence of the high load of asymmetrical bowling action that is performed repeatedly during matches and training. the type and intensity of training that took place during the cricket season may have accounted for the asymmetries in abdominal muscle thickness that were found at the end of the season. acknowledgement. funding was granted by the carnegie foundation, the south african national research foundation and the south african society of physiotherapy. references* 1. engstrom cm, walker dg, kippers v, mehnert aj. quadratus lumborum asymmetry and l4 pars injury in fast bowlers: a prospective mr study. med sci sports exerc 2007;39:910-917. 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[http://dx.doi.org/10.2519/jospt.2009.3128] 11. teyhen ds, williamson jn, carlson nh, et al. ultrasound characteristics of the deep abdominal muscles during the active straight leg raise test. arch phys med rehabil 2009;90:761-767. [http://dx.doi.org/10.1016/j.apmr.2008.11.011] 12. de visser h, adam cj, crozier s, pearcy mj. the role of quadratus lumborum asymmetry in the occurrence of lesions in the lumbar vertebrae of cricket fast bowlers. med eng phys 2007;29:877-885. [http://dx.doi.org/10.1016/j. medengphy.2006.09.010] 13. ferdinands re, kersting u, marshall rn. three-dimensional lumbar segment kinetics of fast bowling in cricket. j biomech 2009;42:1616-1621. [http://dx.doi.org/10.1016/j. jbiomech.2009.04.035] 14. hu h, meijer og, hodges pw, et al. understanding the active straight leg raise (aslr): an electromyographic study in healthy subjects. man ther 2012;17:531-537. [http://dx.doi.org/10.1016/j.math.2012.05.010] 15. davey nj, lisle rm, loxton-edwards b, nowicky av, mcgregor ah. activation of back muscles during voluntary abduction of the contralateral arm in humans. spine (phila pa 1976) 2002;27:1355-1360. [http://dx.doi.org/10.1097/00007632-20020615000019] * a more comprehensive reference list may be obtained from the corresponding author. 50 sajsm vol 22 no. 2 2010 introduction there is a high incidence of injuries among gymnasts.1 this is not surprising given the highly repetitive nature of impacts associated with landings from dismounts and during floor routines. the majority of upper extremity stress fractures involve the distal radius.2 sternal stress fractures are rare, with the only other similar type of injury being described in a 9-year-old gymnast who was training on the parallel bars when he sustained an acute posterior sterno-manubrial dislocation.3 here is a description of a sternal stress fracture in a competitive gymnast. case report a 15-year-old male competitive gymnast presented 1 week after routine training. while performing a floor exercise routine and following a tumble, he experienced central chest pain. as a result he withheld further training and consulted 1 week later, due to ongoing pain. there were no signs of ecchymosis or swelling over the sternum, while tenderness over the body of the sternum was present. the history of pain at rest suggested a fracture rather than bony bruising or a stress reaction. the absence of morning stiffness, which is an important symptom of costochondritis, made the diagnosis of costochondritis unlikely. in addition, the absence of ecchymosis and swelling excluded conditions like the tietze’s syndrome. muscle weakness and skeletal deformities were not found on examination. the rest of the systemic examination was unremarkable. plain chest x-rays (fig. 1) did not show any abnormalities and fractures could not be seen. the patient was referred for a bone scan which was indicative of a sternal stress fracture (fig. 2a, 2b). the scan revealed increased uptake in the body of the sternum, exactly where the pain was located, demonstrating unequal uptake intensity strongly indicative of a stress fracture in the sternum. the patient was treated symptomatically with oral analgesics and anti-inflammatory medication. eight weeks after the onset of symptoms the patient reported no pain and started to train again. four months later he was pain free and fully active. he was also referred for advice on performance technique and education. he has, however, since been lost to follow-up. discussion stress fractures occur owing to repetitive muscular action on a bone. this repetitive stress causes periosteal resorption. sternal stress fractures are rare, and account for only 0.5% of all sternal fractures.4 only four cases have been reported in non-contact sport (table i). upper extremity stress fractures in a gymnast involve the distal radius and scaphoid because of repetitive abduction and dorsiflex movement of the wrist. forty five per cent of all stress fractures in a gymnast involve the pars interarticularis, because of considerable stress on the lower back as a result of repetitive flexion, hyperextension, rotation and compressive loading of the spine on landing.7,8 the mechanism of this stress fracture may be due to sudden forward angulations at the thoracic spine and violent protraction of the shoulders, stressing the sternum via the clavicles. we postulate that the forward flexion on the spine during the repeated tumbles and the motion on assuming the standing position contributed to the injury. the dynamic movement of sudden standing stresses the ribs and the maldistribution of forces across the scalene muscles and pectoralis major, impact on the sternum, resulting in the sternal stress fracture. a common example of poor posture in gymnasts is excessive arching of the back. the manner in which the body is held during both static and dynamic movements can unduly stress sternal structures through maldistribution of forces and body weight over structures that are not suited to the various tasks.2,7 sternal stress fractures heal with no sequelae and complications are rare.9 sternal stress fracture in a gymnast: a case report and literature review correspondence: ismail hassan e-mail: ismail.hassan@ul.ac.za tel: 076 470 6620 ismail hassan (mmed (int med), fcp (sa)) dimakatso althea ramagole (mb chb, msc (sports med)) dina christina janse van rensburg (mb chb, mmed (physmed), msc (sports med)) catharina cornela grant (national diploma in analytical chemistry, bsc, bsc (hons), msc) rob collins msc (sports med) university of pretoria, division sports medicine (centre for sports sciences) case study fig. 1. plain x-ray. sajsm vol 22 no. 2 2010 51 bone scans are sensitive in diagnosing stress fractures of the sternum and are reliable in detecting other bone pathologies, such as lymphoma (appearing as a cold signal) and multiple myeloma which usually has multiple lesions. insufficiency fractures of the sternum have been reported in osteoporosis. this may be of concern in the adult population and adult women suffering from the ‘female athlete triad’.6,7 on the other hand, plain x-rays may not always be conclusive, while lateral x-ray views are superior to axial ct scanning and secondary signs of fracture such as retrosternal haematoma are specific but non-sensitive on ct. the ct scan does not demonstrate the horizontal fracture because of the axial direction. however, it readily demonstrates a retrosternal haematoma, without evidence of spread into the mediastinum – a specific sign of sternal injury (fig. 3). a mediastinal haematoma could also contain venous or arterial blood, hence the importance of clinical cues. due to the slice thickness and rotational cuts employed, the fracture goes unrecognised.10,11 mri is the most sensitive modality overcoming this limitation, and also delineates better anatomical structures for other surrounding pathologies; however, it incurs a higher cost. ultrasound can also be used for diagnosing blunt chest trauma but is operator-dependent. it is useful when contemplating to infuse local anaesthetic into the site for pain relief.10 unless their use is contraindicated, non-steroidal anti-inflammatory drugs (nsaids) are recommended for alleviation of pain and inflammation in impingement injuries, tenosynovitis and inflammatory arthropathy.12 however, nsaids have no effect on fracture healing, and their use in this setting is controversial and limited. paracetamol is recommended for acute and chronic musculoskeletal pain.12 absence from further training is mandatory for healing and preventing complications. preventive measures may incorporate neuromuscular training programmes to enhance proper skill mechanics. equipment with safer design patterns for landing floor mats is recommended. this will facilitate better absorption of landing forces.2 conclusion • this case is in keeping with a sternal stress fracture. the majority of stress fractures in a gymnast occur during practice rather than competition and involve the lower extremities. • having excluded acute trauma and if bone injury is suspected, stress fractures should be entertained in the correct clinical context, even if signs and symptoms appear at unusual sites. • bone scintigraphy has a good application in the diagnosis of stress fracture in this setting. references 1. caine dj, nassar l. gymnastics injuries. med sport sci 2005;48:1858. 2. kolt g. gymnastic injuries – why they occur. austr gymnast 1992;2:1819. 3. nijs s, broos o. sterno-manubrial dislocation in a 9-year-old gymnast. acta chir belg 2005;105:422-424. 4. robertson k, kristensen o, vejen l. manubrium sterni stress fracture: an unusual complication of non-contact sport. br j sports med 1996;30:176-177. 5. barbaix ej. stress fractures of the sternum in a golf player. int j sports med 1996;17:303-304. 6. mccurdie i, etherington j, buchanan n. sternal fracture in a female army officer cadet. br j sports med 1997;31(2):164. 7. dixon m, fricker p. injuries to elite gymnasts over 10 yrs. med sci sports exerc 1993;25(12):1322-1329. 8. keller ms. gymnastics injuries and imaging in children. pediatr radiol 2009;39:1299-1306. 9. chiu wc, d’amelio le, hammond js. sternal fractures in blunt chest trauma: a practical algorithm for management. am j emerg med 1997;15:252-255. 10. hugget jm, rozler mh. ct findings of a sternal fracture. injury 1998;29(8):623-626. 11. anderson mw. imaging of upper extremity stress fractures in the athlete. clin sports med 2006;25:489-504. 12. paoloni ja, milne c, orchard j, et al. non-steroidal anti-inflammatory drugs in sports medicine: guidelines for practical but sensible use. br j sports med 2009;43:863-865. figs 2a and b. right anterior oblique and left anterior oblique scans demonstrating unequal uptake intensity. table i. sport-related sternal stress fractures in noncontact sport sternal stress fracture author sport 1 barbaix 19965 golf 1 robertson 19964 weight lifting 1 mccurdie 19976 triceps dips 1 robertson 19964 abdomen muscle training fig. 3. an example of an axial ct scan. original research 1 sajsm vol. 29 2017 injury incidence and characteristics in south african school first team rugby: a case study j c tee,1 phd; f lebatie,2 bsc (phys); k till,1 phd; b jones,1 phd 1. school of sport, leeds beckett university, leeds, united kingdom 2. floyd lebatie physiotherapy, jeppe high school for boys, kensington south africa corresponding author: j c tee (j.c.tee@leedsbeckett.ac.uk) rugby union is a collision sport, with more than 2.8 million players in 120 countries worldwide. [1] in recent years, the game has been exposed to increasing levels of scrutiny regarding the safety of participation. [2-3] meta-analysis has revealed that the mean injury incidence is 81, 95%ci 63-105 injuries /1 000 h in matches and 3, 95%ci 2-4 injuries /1000 h in training for professional players. [4] recently public interest groups have questioned whether the overall risk of injury, particularly at school level, is acceptable. they have even gone as far as to suggest that tackling should be banned from school rugby. [2] in their response, world rugby have called for longitudinal injury surveillance research to be undertaken at school level in order to accurately quantify the risks to school rugby players. [3] some research on this topic exists, [5-10] but because of the variation in the methods of reporting and injury definitions applied, it is difficult to make comparisons across studies. [3] in the largest and most comprehensive study of this subject to date, palmer-green et al. reported a match injury incidence of 35, 95%ci 29-41 injuries /1 000 player h during matches with a mean injury severity of 30 days (95%ci 25-35) for english school level players. [7] these authors also found that in training, the injury incidence was 1.7 injuries / 1 000 h and mean severity was 27 days (95%ci 9-45). [8] the rugby injury surveillance in ulster schools project reported a match injury incidence of 29 per 1 000 player hours, but did not provide training data. [5] in south africa, landmark studies performed in 1982 and 1987 estimated the “missed subsequent match” injury incidence to be 7, 95%ci 0-21 injuries /1000 player h. [9-10] these studies were conducted before the advent of professionalism in rugby union, and the game has since changed significantly. subsequent to these studies, the focus of youth rugby injury research has been on the national provincial weeks tournaments. [11-13] at these tournaments, it was reported that the match injury incidence was 29, 95%ci 18-39 injuries /1 000 h at u18 level. [11] this research reports the injury profile of a single provincial competition week, but falls short of the type of longitudinal injury surveillance methodology required to make effective risk evaluations regarding the safety of the game at this level. [3] therefore the aim of this present study was to provide a preliminary longitudinal injury case study of a single u19 south african school rugby team. it describes the training habits and exposure levels typical of the south african school rugby system, and provides insights into the injury risks for players at this level. methods participants the team investigated is from a well-established rugby playing school that was ranked in the top 20 rugby schools in south africa at the end of the 2016 rugby season across a range of ranking systems. players were aged between 16 and 18 years on the 1st of january 2016, and were members of the school’s first xv rugby squad. the player cohort comprised 23 players (14 forwards and 9 backs) with physical characteristics as presented in table 1. procedures data regarding all injuries and training exposure throughout the 2016 school rugby season (including the preseason) from 25 january to 6 august 2016 were collected by the team’s strength and conditioning coach. the team’s physiotherapist confirmed background: despite its apparent popularity, participation in the sport of rugby union is accompanied by a significant risk of injury. concerned parties have recently questioned whether this risk is acceptable within school populations. this is difficult to assess within the south african schools’ population as no recent longitudinal injury studies exist. objectives: to determine the training habits, rugby-related exposure and injury risk within a population of south african high school first team rugby players. methods: training and match exposure in both school and provincial competition were examined and the resultant injuries were longitudinally observed for the duration of a south african high school rugby season. results: match (79, 95%ci 52-105 injuries/1 000 h) and training (7, 95%ci 3-11 injuries /1000h) injury incidences were demonstrated to be greater than previously reported incidences in similar populations in england and ireland. weeks where players were exposed to both school and provincial competition (34, 95%ci 19-49 injuries /1 000 h) had significantly (p<0.05) greater injury incidences than during school competition alone (19, 95%ci 12-26 injuries /1 000 h). conclusion: the injury risk demonstrated was greater than expected and represents reasons for concern. possible reasons for the high injury incidence recorded may be the frequency of games played within the season, and the overlap of school and provincial competitions. it should be noted that these results were taken from one school over one season and might not be representative of the incidence of school rugby injuries overall. however, this research demonstrates the need for a multischool longitudinal study within south african schools rugby to determine the overall risk. keywords: rugby union, youth, injury risk, provincial, multicompetition s afr j sports med 2017;29:1-7. doi: 10.17159/2078-516x/2017/v29i0a1532 http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1532 original research sajsm vol. 29 2017 2 all injury diagnoses. these were later retrospectively analysed to determine injury incidence. ethical approval for the study was obtained from the leeds beckett university ethics committee. injuries were classified according to the “time-loss” definition provided by the 2007 international rugby board (irb) consensus statement [14]. injury severity was calculated as the total number of days elapsed from the day of injury until a player returned to full training or match participation. [14] injuries were recorded on an ms excel spreadsheet with a coding system which included the injury date, body site, type of injury, whether the injury occurred during a match or training session, whether the injury occurred as the result of a contact/collision event, and the date that the player returned to full participation following injury. match and training exposure times were individually recorded for each player during each onfield participation. when squad players were not selected for the school’s first xv matches, their exposure in the second xv matches was recorded. these involvements were then summed to provide the overall team match and training exposure time. gym sessions were not included in the analysis. over the course of the study period, players were involved in a multistage provincial trials process, and depending on progression through the trials, players were exposed to additional rugby involvement through provincial training and games. table 2 provides a summary of how the training week is affected when players have to attend both school and provincial training sessions. exposure and injuries due to provincial involvement were treated separately to school team involvement. where it was not possible for the investigator to directly observe these provincial training sessions and matches, exposure time was collected via a player report. figure 1 provides the comparative amount of time spent per week on school and provincial rugby throughout the season. in order to determine the effect of playing for both school and provincial teams simultaneously, injury incidence was compared for weeks where players represented school-only, province-only and school and province combined. table 1. physical characteristics of school player cohort (n=23) whole group (n=23) backs (n=9) forwards (n=14) likelihood and magnitude of difference stature (cm) 178 ± 6 176 ± 7 180 ± 6 likely, medium body mass (kg) 88.4 ± 13.3 78.7 ± 6.8 95.7 ± 12.4 very likely, very large vertical jump (cm) 50 ± 8 54 ± 6 47 ± 7 very likely, large 1rm bench press (kg) 94 ± 15 90 ± 14 98 ± 16 unclear, medium 5rm squat (kg) 132 ± 23 120 ± 22 140 ± 21 likely, large 40m sprint (s) 5.4 ± 0.3 5.2 ± 0.3 5.5 ± 0.3 likely, large yo-yo irt1 (m) 933 ± 354 1217 ± 287 711 ± 216 most likely, very large 1rm, one repetition maximum; 5rm, five repetition maximum; yo-yo irt1, yo-yo intermittent recovery test one. data presented as mean ± sd. likelihood represents the chance that the true value of the difference between groups is substantially positive or negative according to the following scale <1%, almost certainly not; 1% to 5%, very unlikely; 5% to 25%, unlikely; 25% to 75%, possible; 75% to 95%, likely; 95% to 99%, very likely; >99%, almost certain. magnitude of difference represents cohen’s effect size statistic. ess of 0.2, 0.6, 1.2 and 2.0 were considered small, medium, large and very large respectively. table 2. in-season weekly training schedule for a south african high school rugby first team during weeks representing the school only or school and province combined school-only school and province combined day activity time (mins) activity time (mins) monday gym aerobic training and small sided games total 45 60 105 provincial training (combination of attack, defence and unit skills) total 100 100 tuesday warm up and skills defence breakdown units skills (backs/forwards) total 20 30 30 30 110 warm up provincial match total 20 60 80 wednesday rest (occasional additional lineout session for forwards) total (30) (30) rest total 0 thursday gym speed and agility attack skills and structure unit skills (backs/forwards) total 30 20 45 30 125 gym speed and agility breakdown/defence attack structure unit skills (backs/forwards) total 30 20 30 30 30 140 friday captains run total 30 30 captains run total 30 30 saturday warm up match total 30 70 100 warm up match total 30 70 100 sunday rest / recovery total 0 rest / recovery total 0 total for week 470 450 original research 3 sajsm vol. 29 2017 statistical analyses injury incidence was calculated for matches, training and overall rugby exposure as the number of injuries per 1 000 player hours for both school and provincial rugby exposure. independent injury incidences were further calculated for periods of the season where players participated in school-only (17 weeks), province-only (five weeks) and school and province combined (six weeks) rugby. 95% confidence intervals (95%ci) were calculated according to the methods of knowles et al.[16] injury incidence between different groups (e.g. backs vs. forwards) or studies was compared by calculating incidence rate ratios (irr) and magnitude-based inferences (mbi) using a custom designed spreadsheet (www.sportsci.org). [15] mbi represents the likelihood that the true value is substantially positive or negative according to the following scale <1%, most unlikely; 1% to 5%, very unlikely; 5% to 25%, unlikely; 25% to 75%, possibly; 75% to 95%, likely; 95% to 99%, very likely; >99%, most likely. injury severity was calculated as the mean ± sd number of days absence from training and match play. however, given the practical nature of this study, the size of effect was assessed calculating cohen’s effect size (es) statistic. [15] ess of 0.2, 0.6, 1.2 and 2.0 were considered small, medium, large and very large respectively. [15] injury burden was calculated as the total number of days absent from training and match play. results exposure in total, players were exposed to 2 088 hours of rugby activity during the school season (training 1 668 hours, matches 420 hours). this equated to a total of 78 scheduled training sessions and 20 interschool matches over the season (training to match ratio approx. 4:1). participation in provincial rugby led to an additional 221 hours of rugby exposure (training 142 hours, matches 79 hours). consequently, on average, each school player was exposed to an additional 4 ± 5 (range 0 to 14) training sessions and 4 ± 3 (range 1 to 8) matches (training to match ratio approx. 1:1). incidence of injury match vs. training overall, a total of 54 time-loss injuries were sustained (42 match, 12 training). the overall injury incidence was 23 injuries per 1 000 player exposure hours (95%ci 17-30). the match injury incidence (84 injuries per 1 000 match hours; 95%ci, 59110) was most likely greater that the training injury incidence (7 injuries per 1 000 training hours; 95%ci 3-10) (irr 12.0 95%ci 6.8-22.1) (table 3). injury incidence for school and provincial fig. 1. average weekly exposure of south african high school rugby players to school and provincial rugby. table 3. comparison of injury incidence during matches and training for backs and forwards for all exposures all competition match vs. training overall matches training mbi irr (95%ci) all players injuries (n) 54 42 12 most likely 12.0 (6.8 – 21.2) incidence 23 84 7 (95%ci) (17 30) (59 110) (3 10) backs injuries (n) 25 21 4 very likely 18.8 (2.6 – 134.8) incidence 25 94 5 (95%ci) (15 35) (54 134) (0 10) forwards injuries (n) 29 21 8 most likely 9.5 (4.0 – 22.7) incidence 22 76 8 (95%ci) (14 29) (44 109) (2 13) backs vs. forwards mbi trivial possibly unclear irr (95%ci) 1.1 (0.7 to 1.8) 1.2 (0.7 to 2.1) mbi, magnitude based inference; irr, incidence injuries ratio injuries indicates the total number of injuries that occurred. incidence is the number of injuries per 1 000 hours of exposure time (95%ci). mbi represents the likelihood that the true value is substantially positive or negative according to the following scale <1%, most unlikely; 1% to 5%, very unlikely; 5% to 25%, unlikely; 25% to 75%, possibly; 75% to 95%, likely; 95% to 99%, very likely; >99%, most likely. irr represents the incidence rate ration with 95% confidence intervals. http://www.sportsci.org/ original research sajsm vol. 29 2017 4 exposures are provided in table 4. backs vs. forwards backs had a possibly greater match injury incidence than forwards in school rugby (backs 99, 95%ci 54-145 vs. forwards 63, 95%ci 31-95 injuries /1 000 h, irr 1.6, 95%ci 0.8 – 2.9) (table 4). when playing provincial rugby forwards had a likely higher match injury incidence than backs (backs 70, 95%ci 9-149 vs. forwards 167, 95% ci 33-300 injuries /1 000 h, irr 2.4, 95%ci 0.5 – 10.7). provincial vs. school rugby periods of the season when players participated in school-only rugby (17 weeks), province-only rugby (five weeks), and in school and province combined rugby (six weeks) were compared for overall injury incidence. injury incidence was likely greater in the weeks where players participated in both school and province combined rugby compared with schoolonly participation (school-only 19, 95%ci 12-26 vs. school and province combined 34, 95%ci 19-49 injuries /1 000 h, irr 1.8, 95%ci 1.1 – 3.0) (figure 2). the difference between table 4. comparison of injury incidence during matches and training for backs and forwards for school and provincial exposures school competition match vs. training provincial competition match vs. training overall matches training mbi irr (95%ci) overall matches training mbi all players injuries (n) 45 33 12 most likely 11.3 (6.1 – 21.0) 9 9 0 unclear incidence 22 79 7 41 114 0 (95%ci) (15 28) (52 105) (3 11) (14 68) (40 188) 0 backs injuries (n) 22 18 4 very likely 16.5 (2.1 – 128.3) 3 3 0 unclear incidence 26 99 6 23 70 0 (95%ci) (15 37) (54 145) (0 12) (-3 50) (-9 149) 0 forwards injuries (n) 23 15 8 most likely 7.9 (3.7 – 16.6) 6 6 0 unclear incidence 18 63 8 64 167 0 (95%ci) (11 26) (31 95) (2 8) (13 115) (33 300) 0 backs vs. forwards mbi possibly possibly unclear unclear unclear unclear irr (95%ci) 1.4 (0.9 to 2.4) 1.6 (0.8 to 2.9) mbi, magnitude based inference; irr, incidence injuries ratio injuries indicates the total number of injuries that occurred. incidence is the number of injuries per 1 000 hours of exposure time (95%ci). mbi represents the likelihood that the true value is substantially positive or negative according to the following scale <1%, most unlikely; 1% to 5%, very unlikely; 5% to 25%, unlikely; 25% to 75%, possibly; 75% to 95%, likely; 95% to 99%, very likely; >99%, most likely. irr represents the incidence rate ration with 95% confidence intervals. table 5. comparison of injury severity (days) during matches and training for backs and forwards for all exposures all competition match vs. training overall matches training mbi effect size all players 15 ± 36 18 ± 40 3 ± 2 likely small (0.42) backs 5 ± 4 5 ± 4 3 ± 1 most likely trivial forwards 24 ± 47 32 ± 54 3 ± 2 likely medium (0.62) backs vs. forwards mbi likely very likely most likely effect size small (0.55) medium (0.71) trivial mbi, magnitude based inference. data are presented as mean ± sd. mbi represents the likelihood that the true value is substantially positive or negative according to the following scale <1%, most unlikely; 1% to 5%, very unlikely; 5% to 25%, unlikely; 25% to 75%, possibly; 75% to 95%, likely; 95% to 99%, very likely; >99%, most likely. effect size is cohen’s effect size (es) statistic. ess of 0.2, 0.6, 1.2 and 2.0 were considered small, medium, large and very large respectively . fig.2. injury incidence during periods where players are exposed to only school, only provincial and to school and provincial rugby. * indicates likely difference from school rugby. original research 5 sajsm vol. 29 2017 provincial-only and school and province combined participation was unclear (provincial participation only 23, 95%ci -3-49 vs. school and provincial participation 34, 95%ci 19-49 injuries /1 000 h). injury severity the mean severity of all injuries sustained was 15 ± 36 days. data on the severity of injuries for backs and forwards in school and provincial competition are provided in tables 5 and 6. overall, there was a likely small difference in the severity of injuries sustained in matches and training (match 18 ± 40 vs. training 3 ± 2 days, es = 0.42). a very likely medium difference was present for match injury severity between backs and forwards (backs 5 ± 4 vs. forwards 32 ± 54, es = 0.71). the effect of this was that despite sustaining a similar number of overall injuries table 6. comparison of injury severity during matches and training for backs and forwards for school and provincial exposures school rugby match vs. training provincial rugby match vs. training overall matches training mbi irr (95%ci) overall matches training mbi all players 13 ± 30 16 ± 34 3 ± 2 possibly small (0.45) 27 ± 58 27 ± 58 unclear backs 5 ± 4 5 ± 5 3 ± 1 most likely trivial 5 ± 4 5 ± 4 unclear forwards 20 ± 41 29 ± 48 3 ± 2 likely medium (0.66) 38 ± 70 38 ± 70 unclear backs vs. forwards mbi likely likely most likely unclear unclear effect size small (0.51) medium (0.74) trivial small (0.56) small (0.56) mbi, magnitude based inference. data are presented as mean ± sd. mbi represents the likelihood that the true value is substantially positive or negative according to the following scale <1%, most unlikely; 1% to 5%, very unlikely; 5% to 25%, unlikely; 25% to 75%, possibly; 75% to 95%, likely; 95% to 99%, very likely; >99%, most likely. effect size is cohen’s effect size (es) statistic. ess of 0.2, 0.6, 1.2 and 2.0 were considered small, medium, large and very large respectively table 7. burden of injury in a south african high school rugby first team as a function of injury site and type brain bone joint / ligament muscle / tendon total concussion non-fracture sprain lesion of meniscus, cartilage or disc muscle rupture/ tear/ strain/ cramp tendon injury/ rupture/ tendinopathy/ bursitis haematoma/ contusion/ bruise head / face 19 (1) 6 (1) 25 (2) neck / cervical spine 2 (1) 4 (1) 6 (2) sternum / ribs 3 (1) 1 (1) 4 (2) shoulder / clavicle 10 (1) 110 (2) 14 (3) 134 (6) elbow 2 (1) 2 (1) hip / groin 7 (2) 7 (2) anterior thigh 9 (3) 9 (3) posterior thigh 72 (7) 72 (7) knee 227 (11) 9 (2) 1 (1) 237 (14) lower leg / achilles 20 (3) 20 (3) ankle 288 (10) 288 (10) foot / toe 2 (1) 4 (1) 6 (2) total 19 (1) 2 (1) 515 (21) 13 (2) 211 (15) 11 (3) 39 (11) 810 (54) data are presented as injury burden, the total number of injury days followed by (number of injuries). fig.3. relative contribution of forwards and backs contact and non-contact injuries to the total team injury burden. original research sajsm vol. 29 2017 6 (backs 25 vs. forwards 29), forwards contributed 85% of the team injury burden (figure 3). nature of injury the lower limb was the most commonly injured body area for both backs (88%, 22 of 25) and forwards (66%, 19 of 29). forwards experienced a greater proportion of upper limb injuries relative to backs (backs 0%, 0 of 25 injuries vs. forwards 24%, 7 of 29). injury incidence and severity were combined to provide the total injury burden by injury site and type (table 7). the most costly injuries were ligament sprain type injuries to the knee and ankle which when combined accounted for 64% (515 of 810 days) of the total season injury burden. the majority of injuries (69%, 37 of 54) occurred as a result of contact events. there was a possibly small difference in the severity of contact versus non-contact injuries (contact 19 ± 42 vs. non-contact 7 ± 13, es = 0.34). in total, 692 (85%) training days were lost to contact injury and 122 (15%) days were lost to non-contact injury. discussion this is the first study since 1987 to determine the incidence, severity and nature of injury in a south african high school rugby first team using a longitudinal approach to data collection. the key finding of this study was that the injury incidence observed in this player cohort was much larger than would be expected for a group of school-level rugby players. given that this was a case study, the sample examined was not large enough to provide definitive analysis of the risks that players are exposed to within this category. however, the observations highlighted here illustrate the need for a larger study of this type that incorporates multiple schools. this study shows that in this cohort, the match injury incidence (79, 95%ci 52-105 injuries/1 000 h) is most likely higher than that reported for similar population groups in england (35, 95%ci 29-41 injuries/1 000 h; irr 2.3, 95%ci 1.6-3.1), [7] ireland (29, 95%ci 18-40 injuries /1 000 h; irr 2.7, 95%ci 1.7-4.3)[5] and scotland (11, 95%ci 5-18 injuries /1 000 h; irr 7.2, 95%ci 3.9-13.3). [6] similarly, the training injury incidence in this study (7, 95%ci 3-11 injuries /1 000h) was very likely greater than that reported in england (2, 95%ci 1-3 injuries /1 000 h; irr 3.5, 95%ci 1.7-7.1). [8] despite the greater injury incidence, the mean severity of match injuries (16 ± 34 days) in this cohort, was likely lower than in england (30 ± 30 days) [7] and ireland (24 ± 20 days). [5] similarly, the severity of training injuries was very likely lower in this cohort (3 ± 2 days) than the england group (27 ± 55 days). [8] some of the differences between these studies might be explained by different reporting methods (e.g., whether the researcher was also the primary data collector) in these studies. [3] despite these inconsistencies, it is still evident that the injury incidence in this study is higher than previously reported. [5-10] this is illustrated by the fact that the incidence reported here is comparable with the incidence in men’s senior professional rugby (81 injuries per 1 000 training hours; 95%ci 63-105). [4] these results suggest that the risk of injury in south african school first team rugby is higher than what had previously been determined in other school cohorts. [9-10] when players participated in provincial rugby the match injury incidence was 114, 95%ci 40-188 injuries /1 000 h. this incidence is very likely higher than the english equivalent of academy rugby (47, 95%ci 38-45 injuries /1 000 h) [7], and most likely higher than that reported for provincial youth week tournaments in south africa (29, 95%ci 18-39 injuries /1 000h). [11] this injury incidence was similar to the injury rate reported for international rugby (123, 95%ci 85-177 injuries /1 000h). [4] this is consistent with observations that injury risk increases with playing level [4], but also indicates that the risk in this cohort is higher than previously reported for similar groups. [7] the nature of injury described in this study was consistent with that previously described across school-, academyand professional levels within the game. [4-11] the lower limb was the most frequently injured body part, and accounted for 76% of all injuries. muscle and tendon injuries were the most frequent injury type, followed closely by joint and ligament injuries. joint and ligament injuries resulted in the greatest injury burden, and accounted for 64% of the total time lost. the majority of injuries (69%) occurred as a result of involvement in a contact event. these results agree with previous research that determined that the tackle is the phase of play most likely to cause injury. [12-13] it is difficult to determine why the injury incidence in this study was so high compared to other school cohorts. a possible explanation is that due to the heightened profile of school first team rugby in south africa considerable resources are spent on the recruitment and strength and conditioning of players. stronger and fitter players are able to exert greater force during tackles and collisions, and may be involved in these phases of play more frequently, thus exposing them to greater risk of injury. [7] this effect is demonstrated by the observation that despite greater body mass and strength (table 1), forwards accounted for 85% of the total team injury burden (figure 3). injury incidence was higher in provincial matches for forwards, where the majority of players are likely to be better conditioned. the effect may not have been as pronounced for backs, as it is known that backs are exposed to fewer contact events during a match. [17] a second possible explanation is that structure of the south african school rugby season, where players are regularly required to participate in two and sometimes three games per week, is not optimal. these periods lead to reduced opportunity for recovery, causing players to enter subsequent exposure bouts fatigued. [18] these periods reduce the time that could be spent on conditioning activities, thus these players may be less well prepared physically for matches later in the season. a further contributing factor may be the overlap between school competition and provincial trials competition. it was demonstrated that in the weeks where players participated in both school and province rugby combined, the injury incidence was likely higher than when they participated in original research 7 sajsm vol. 29 2017 school rugby only (school only 19, 95%ci 12 to 26 vs. school and provincial 34, 95%ci 19 to 49 injuries per 1 000 hours; irr 1.8, 95%ci 1.1 – 3.0) (figure 2). it is important to note that this effect is unlikely to be only due to increased match frequency. in both school-only (easter festivals) and provincial-only competition (craven week) players were exposed to periods where they played three matches in a week. it seems that the participation for two different teams in different competitions in the same week is an injury risk factor. this might be due to misalignment between schools and provincial training. in these weeks, due to pressure to complete the necessary technical/tactical work required, it is unlikely that adequate attention is paid to conditioning and recovery activities. in addition, playing within two different team environments may contribute to the accumulation of psychological and emotional stress within players. efforts should be made to reduce congestion in this period of the season, or to reschedule these competitions to prevent overlap. further research should aim to determine how the stress of two different playing environments (e.g. school and academy, or club and country) may affect player wellbeing and injury risk. conclusion this is the first longitudinal injury research project to be undertaken in south african school rugby since the advent of professionalism. the injury risk demonstrated was much larger than would be expected for a cohort of schoolboy rugby players, which is reason for concern. possible reasons for the high injury incidence recorded may be the frequency of games within the season, and the overlap of school and provincial competitions. however, a major limitation of this study is the small sample size used, and the fact that all players represented the same school team. this research demonstrates the need for a larger multischool longitudinal study with south african school rugby to determine the overall risk, and what can be done to mitigate these risks within this population. acknowledgements: thanks to the players and coaching staff of the jeppe high school for boys for their cooperation in this research project. references 1. world rugby. 2017. player numbers (cited 13 april 2017) [http://www.worldrugby.org/development/player-numbers] 2. sport collision injury collective. 2016. open letter: preventing injuries in children playing school rugby (cited 11 march 2016). [http://www.sportcic.com/resources/open%20letter%20spo rtcic%20march1st%202016.pdf] 3. tucker r, raftery m, verhagen e. injury risk and a tackle ban in youth rugby union: reviewing the evidence and searching for targeted, effective interventions. a critical review. br j sports med 2016 aug;50(15):921-925. pmid: 27324873 doi:10.1136/bjsports-2016-096322 4. williams s, trewartha g, kemp s, et al. a meta-analysis of injuries in senior men's professional rugby union. sports med 2013 oct;43(10):1043-1055. pmid:23839770 doi: 10.1007/s40279-013-0078-1 5. archbold ha, rankin at, webb m, et al. risus study: rugby injury surveillance in ulster schools. br j sports med 2017 apr;51(7):600-606. pmid: 26701931 doi:10.1136/bjsports-2015095491 6. nicol a, pollock a, kirkwood g, et al. rugby union injuries in scottish schools. j public health (oxf) 2011 jun;33(2):256-261. pmid: 20581127 doi:10.1093/ pubmed/fdq047 7. palmer-green ds, stokes ka, fuller cw, et al. match injuries in english youth academy and schools rugby union: an epidemiological study. am j sports med 2013 apr;41(4):749755. pmid: 23380159 doi:10.1177/0363546512473818 8. palmer-green ds, stokes ka, fuller cw, et al. training activities and injuries in english youth academy and schools rugby union. am j sports med 2015 feb;43(2):475-481. pmid: 25512663 doi:10.1177/0363546514560337 9. roux ce, goedeke r, visser gr. the epidemiology of school boy rugby injuries. s afr med j 1987 mar;71(5):307-313 10. nathan m, goedeke r, noakes td. the incidence and nature of rugby injuries experienced at one school during the 1982 rugby season. s afr med j 1983 jul;64:132-137 11. brown jc, verhagen e, viljoen w, et al. the incidence and severity of injuries at the 2011 south african rugby union (saru) youth week tournaments. s afr j sports med 2012;24(2):49-54. doi: 10.17159/2413-3108/2012/ 12. burger n, lambert mi, viljoen w, et al. tackle technique and tackle-related injuries in high-level south african rugby union under-18 players: real-match video analysis. br j sports med 2016 aug;50(15):932-9388. pmid: 26781294 doi: 10.1136/bjsports-2015-095295 13. burger n, lambert mi, viljoen w, et al. tackle-related injury rates and nature of injuries in south african youth week tournament rugby union players (under-13 to under-18): an observational cohort study. bmj open 2014 aug;4(8):e005556. pmid: 25116454 doi:10.1136/bmjopen-2014-005556 14. fuller cw, molloy mg, bagate c, et al. consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union. br j sports med 2007 may;41(5):328331. pmid: 17452684 doi:10.1136/bjsm.2006.033282 15. hopkins wg, marshall sw, batterham am, et al. progressive statistics for studies in sports medicine and exercise science. med sci sports exerc 2009 jan;41(1):3-13. pmid: 19092709 doi:10.1249/mss.0b013e31818cb278 16. knowles sb, marshall sw, guskiewicz km. issues in estimating risks and rates in sports injury research. j athl train 2006 apr-jun;41(2):207-215. pmid: 16791309 17. deutsch mu, kearney ga, rehrer nj. time motion analysis of professional rugby union players during match-play. j sports sci 2007 feb 15;25(4):461-472. pmid: 17365533 doi:10.1080/02640410600631298 18. roe g, till k, darrall-jones j, et al. changes in markers of fatigue following a competitive match in elite academy rugby union players. s afr j sports med 2016;28(1):2-5 doi: 10.17159/2078-516x/2016/v28i1a418 http://www.worldrugby.org/development/player-numbers https://dx.doi.org/10.1136/bjsports-2016-096322 https://dx.doi.org/10.1007/s40279-013-0078-1 https://dx.doi.org/10.1136/bjsports-2015-095491 https://dx.doi.org/10.1136/bjsports-2015-095491 https://dx.doi.org/10.1093/pubmed/fdq047 https://dx.doi.org/10.1177/0363546512473818 https://dx.doi.org/10.1177/0363546514560337 https://dx.doi.org/10.1136/bjsports-2015-095295 https://dx.doi.org/10.1136/bmjopen-2014-005556 https://dx.doi.org/10.1136/bjsm.2006.033282 https://dx.doi.org/10.1249/mss.0b013e31818cb278 https://dx.doi.org/10.1080/02640410600631298 1� sajsm vol 20 no. 1 2008 26. milne s, brosseau l, robinson v, et al. continuous passive motion following total knee arthrosplasty (review). cochrane database syst rev 2003; issue 2. art no.: cd004260. doi: 10.1002/14651858.cd 004260. 27. moore kl, dalley af. clinical oriented anatomy, 4th ed. philadelphia: lippincott, williams and wilkins, 1999; 532. 28. morrissey mc, brewster ce, shields cl jr, brown m. the effects of electrical stimulation on the quadriceps during postoperative knee immobilization. am j sports med 1985;13: 40-5. 29. portney lg, watkins mp. foundations of clinical research: applications to practice, 2nd ed. new jersey: prentice-hall, inc., 2000: 35, 402-3. 30. renstrom p, arms sw, stanwyck ts. strain within the anterior cruciate ligament during hamstring and quadriceps activity. am j sports med 1986; 14: 83-7. 31. roi gs, nanni g, tencone f. time to return to professional soccer matches after acl reconstruction. sport sciences for health 2006; 1: 142-5. 32. shaw t, mcevoy m, mcclelland j. an australian survey of in-patient protocols for quadriceps exercises following anterior cruciate ligament reconstruction. j sci med sport 2002; 5: 291-6. 33. shaw t, williams mt, chipchase ls. a user’s guide to outcome measurement following acl reconstruction. phys ther sport 2004; 5: 57-67. 34. shaw t, williams mt, chipchase ls. do early quadriceps exercises affect the outcome of acl reconstruction? a randomised controlled trial. aust j physiother 2005; 51: 9-17. 35. tay gh, warrier sk, marquis g. indirect patella fractures following acl reconstruction: a review. acta orthopaedica 2006; 77: 494-500. 36. trees ah, howe te, dixon j, white l. exercise for treating isolated anterior cruciate ligament injuries in adults. cochrane database syst rev 2005; issue 4. art. no: cd005316. doi: 10.1002/14651858.cd005316. 37. trees ah, howe te, grant m, gray hg. exercise for treating anterior cruciate ligament injuries in combination with collateral ligament and meniscal damag of the knee in adult: review. cochrane database syst rev 2007; issue 3. art no.:cd005961. doi:10.1002/14651858. cd005961. pub2 38. tyler tf, mchugh mp, gleim gw, nicholas sj. the effect of immediate weightbearing after anterior cruciate ligament reconstruction. clin orthop relat res 1998; 357: 141-8. 39. williams gn, barrance pj, snyder-mackler l, buchanan ts. altered quadriceps control in people with anterior cruciate ligament deficiency. med sci sports exerc 2004; 36: 1089-97. 40. williams gn, buchanan ts, barrance pj, axe mj, snyder-mackler l. quadriceps weakness, atrophy and activation failure in predicted noncopers after anterior cruciate ligament injury. am j sport med 2005; 33: 402-7. 41. woo sl, fow rj, sakane m, livesay ga, rudy tw, fu fh. biomechanics of the acl: measurements of in situ force in the acl and knee kinematics. knee 1998; 5: 267-88. 42. yamamoto y, hsu wh, woo sl, van scyoc ah. knee stability and graft function after anterior cruciate ligament reconstruction: a comparison of lateral and anatomical femoral tunnel placement. am j sport med 2004; 32: 1825-32. introduction anterior knee pain is a common condition that affects a wide age range of patients. 5 the condition is often self-limiting, but can take up to 2 years to resolve. 16 it frequently interferes with exeroriginal research article a conservative programme for treatment of anterior knee pain in adolescents abstract objective. the purpose of this study was to determine the effectiveness of a 2½-week conservative rehabilitation programme in addressing anterior knee pain in adolescents. design. subjects were randomly allocated to a control group (n=12) and an experimental group (n=18). the experimental group was subjected to a 2½-week strength, flexibility and neuromuscular rehabilitation programme. both groups were tested before and after the 2½ weeks and the experimental group also 1 month after the post-test. results. the experimental group reported significant (p<0.01) improvement in pain (visual analogue scale), dis ability (patient-specific functional scale) and condition correspondence: professor mf coetsee university of zululand private bag x1001 kwadlangezwa 3886 tel: 27 35 772-6639 e-mail: mcoetsee@absamail.co.za jacqueline phillips (bsc hons biokinetics) marius f coetsee (phd) department of human movement science, university of zululand, kwadlangezwa (scale for change in condition). the experimental group tested significantly (p<0.01) better for strength (quadriceps and hamstrings), flexibility (quadriceps, hamstrings and gastrocnemius) and neuromuscular control (willknox wobble board and bass test of dynamic balance). the control group experienced no improvement in any of the tests. conclusions. the 2½-week rehabilitation programme for addressing anterior knee pain in adolescents proved to be effective. the study demonstrated good retention of improvements and even further improvement after cessation of the programme. advantages are the short duration and the fact that patients are familiarised with a home programme which they are likely to continue with. although not addressed in this study, literature indicates that restoration of neuromuscular control might be the main contributing factor for the success of the programme. pg4-20.indd 14 4/23/08 11:31:06 am sajsm vol 20 no. 1 2008 1� cise and sports participation, and as a result a large number of adolescents may be forced to limit their participation in physical activity or perform sub-optimally on the sports field. 8,27,4 inactivity negatively affects physical development, general fitness, body composition, the development of motor skills and psychosocial development in growing children. 16,6 there is a lack of consensus in the literature, especially in earlier studies, as to the exact definition of anterior knee pain. anterior knee pain, patello-femoral pain, chondromalacia patella and patello-femoral arthralgia were used interchangeably in the past. one of the most common abnormalities involving the knee joint is disturbance of the patello-femoral mechanism. 23 over the years a number of stereotypical symptoms have been identified, namely: pain in the vicinity of the patella worsened by prolonged sitting, ascending or descending stairs, squatting and vigorous physical activity. 5,27,21 the onset of anterior knee pain is insidious, and tends to be bilateral. 21,24,17 the condition is common among adolescents and young adults, especially females. 27,24,7 the exact aetiology is unknown but a number of predisposing factors have been suggested as possible causes. 27 these include overuse, muscle imbalance, muscle tightness, trauma, overweight, genetic predisposition, valgus or varus knee, external tibial torsion, increased q angle, abnormal mechanics of the foot and ankle, especially pronation, and generalised ligament laxity. 27,17,13 in many cases it appears that the onset of anterior knee pain coincides with the period of the adolescent growth spurt. 19 surgical intervention is not recommended and often there is no demonstrable anatomical abnormality. 16 conservative treatment for anterior knee pain should always be the first approach. 22 many studies reported good results with conservative treatment. 26,13,28 rehabilitation programmes reported in the literature lasted between 6 and 12 weeks. 27,4,13 however, practical experience in the south african context has shown that patient compliance is poor with a programme that exceeds 3 weeks. many years of experience in a biokinetic (physical therapy) practice have evolved a rehabilitation protocol of 2½ weeks for knee rehabilitation that is perceived to be highly successful. this programme concentrates on improvement of strength, flexibility and especially neuromuscular control in an attempt to stabilise the knee joint. the focus of this study was therefore to test the effective-ness of a 2½-week physical rehabilitation programme in alleviating anterior knee pain in adolescents. the term anterior knee pain is used to describe the symptom complex characterised by pain in the anterior region of the knee during activity in the absence of an identifiable pathological condition. methods approval for the study was obtained from the faculty of science and agriculture ethics committee, university of zululand. all subjects and their parents completed an informed consent form prior to testing. potential subjects were identified from responses to an article that appeared in the local newspaper, referrals from doctors and from responses to a questionnaire distributed to pupils at 9 local schools. subjects had to be between the ages of 10 and 17 years and both males and females were eligible. criteria for positive anterior knee pain were: pain on the anterior surface of the knee in excess of 1 month's duration, pain intensity of moderate to severe and pain that interfered with sport participation. exclusion criteria were: previously diagnosed ligamentous, meniscal, tendon, fat pad or bursae involvement; previous surgery; history of patella dislocation or subluxation; osgood-schlatter’s disease and sinding-larsen-johannsen disease. skyline, lateral and anteroposterior view x-rays were taken of potential candidates. final subject selection was determined by an orthopaedic surgeon after a physical examination and examination of the x-rays. subjects meeting the above criteria were randomly allocated to either the control or experimental group. the control group (n=12) underwent pre-testing and 2½ weeks later post-testing, and continued with normal everyday activity over this period. the experimental group (n=18) underwent pre-testing, 2½-week intervention, post-testing and post-post testing 1 month postintervention. the intervention programme was offered to the subjects of the control group after the post-tests were concluded. subjects were dressed in a t-shirt, shorts and exercise shoes during testing. the following three subjective tests were selected to quantify reduction in pain and disability: • pain was rated using the visual analogue scale (vas). the vas has been found to be a reliable and valid tool for measuring pain. 27,12 it has also been shown to be a valid indicator of pain changes in patients with anterior knee pain. 18 the vas is a 10-cm horizontal line marked at 1-cm intervals, the ends of which define the minimum (no pain) and maximum (severe pain) of perceived pain. subjects indicated the intensity of their pain with a mark on the line. normal, least and worst pain experienced in the past week was documented. • level of disability was rated using the patient-specific functional scale (psfs). 3 test-retest reliability is excellent, and it is a valid and responsive tool. 3,11 this instrument aids clinicians in assessing the change in health or functional status of individual patients. 3,25 patients were asked to identify up to 5 activities which they were experiencing difficulty with or were unable to perform because of their knee pain and then to rate the current level of difficulty associated with each activity from 0 (unable to perform activity) to 10 (able to perform activity at same level as before injury or problem). • overall improvement at the post-test and post-post-test was measured using the scale for change in condition. 9 this 4point scale is useful for assessing the change in functional status of individual patients. 9 the following six objective tests were selected for measurement of performance: • measurements of maximal quadriceps and hamstring muscle strength were recorded during closed-kinetic-chain isometric knee flexion and extension using a dynamometer. the testretest reliability was determined in a pilot study using healthy subjects. subjects were positioned with the knee at 90 degrees of flexion and given one practice trial, whereafter the highest value of three attempts was recorded. subjects rested for 30 seconds between attempts. • the straight leg hamstring test was used to measure hamstring flexibility. 29 the subject lay supine on the plinth pg4-20.indd 15 4/23/08 11:31:07 am 1� sajsm vol 20 no. 1 2008 with one leg secured to the plinth to prevent hip flexion. the other leg was passively lifted by the researcher flexing the hip joint until the hamstring started to flex the knee. the angle of hip flexion was measured using a goniometer. • the modified thomas test was used to measure flexibility of the quadriceps muscles. 10 the subject sat on the end of the plinth, and rolled back pulling both knees to the chest. this ensured that the pelvis was in posterior rotation and that the lumbar spine was flat on the plinth. the subject then lowered one leg towards the floor while holding the contralateral limb in maximum flexion with the arms. the angle of knee flexion was measured. • the straight leg gastrocnemius test was used to measure flexibility of the gastrocnemius. 29 the patient positioned the foot of the leg being measured on a mark 0.6 m from the plinth and with the hands on the plinth leant forward as far as possible while keeping the heel on the floor and the leg straight. the other leg was used for balance, and was bent. the angle of ankle dorsiflexion was measured. • proprioception (neuromuscular control) of the lower limbs was measured on the willknox wobble board, which is an apparatus built at the university of zululand and records the time that the rim of the wobble board touches the floor. the subject balanced on the wobble board while trying not to touch the rim to the floor but, most importantly, if the rim did touch to lift it as quickly as possible. time that the rim touched the floor during a 2-minute period was recorded. • the bass test of dynamic balance 2 was used to measure dynamic balance. a reliability coefficient of 0.95 was obtained with female college students as subjects. the subject stood with the right foot in the starting circle, jumped into the first circle with the left foot and thereafter jumped from circle to circle, alternating the feet. the subject had to land on the ball table ii. percentage differences between prev. postand prev. post-post mean ratings of worst, least and normal pain (points) as indicated on the visual analogue scale (vas), for the control (n=12) and experimental (n=18) groups. points data expressed as mean ± sd group worst pre worst pre least least pre normal normal v. post v. post-post pre v. post v. post pre v. pre v. post post post-post control 6.6±0.9 v. n/a 2.5±0.9 v. n/a 4.6±1.4 v. n/a 6.8±0.7 3.0±0.5 4.6±0.8 +3.0% +20.0% † 0% experimental 7.1±1.2 v. 7.1±1.2 v. 3.3±1.8 v. 3.3±1.8 v. 5.4±1.9 v. 5.4±1.9 v. 4.0±0.9 4.1±1.0 2.1±1.2 2.1±0.8 3.1±1.3 3.2±1.5 -43.0%* -42.8%* -35.3%* -37.5%* -42.0%* -41.6%* * p<0.01 † p<0.05) table i. intervention programme followed during contact sessions intervention activity speed or repetitions sets rest modality intensity open-kinetic-chain 50 60% effort 120 deg.s-1 10 3 isokinetic knee 100 deg.s-1 10 warm-up and 80 deg.s-1 8 20 s strengthening 100% effort 60 deg.s-1 6 2 3 40 deg.s-1 4 wobble board balancing max effort 2 min mini-trampoline jog maintaining 30 s routine 2 bounce/leg neuro 30 s 3 bounce/leg muscular 30 s 1 continuous 1 leg only bounce control at 2 x 15 s 2 leg bounce all times 30 s twist 30 s 1 leg twist 2 x 15 s mat jumping 1. forward back maintaining routine 2. side side neuro 3. clockwise muscular 1 4. anti-clockwise control at 3 5 x 5 s 5. cross forwards all times 6. cross backwards pg4-20.indd 16 4/23/08 11:31:08 am sajsm vol 20 no. 1 2008 1� of the foot, and not allow the heel to touch the ground. each error counted as a penalty point every time it occurred. errors included the following: (i) the heel touching the ground; (ii) moving or hopping on the supporting foot while in the circle; (iii) touching the floor outside a circle with the supporting foot; and (iv) touching the floor with the free foot or any other part of the body. the timer counted the seconds (up to 5 seconds) out loud, beginning the count as the subject landed in the circle. counting was restarted if the performer leapt to the next circle in less than 5 seconds. if the subject spent more than 5 seconds in the circle, the extra time was deducted from the total time. errors were counted silently and cumulatively by the tester, who followed the subject closely. a total of 5 trials were given, 3 of which were practice runs. the final score was the total time plus 50, minus 3 times the total number of errors. the better score of the last 2 trials was used. the intervention programme included muscle strength, proprioception and dynamic stability training done during 5 contact sessions of 45 minutes each and 5 home sessions of 30 minutes each. the contact sessions as shown in table i included the following: strengthening of the quadriceps and hamstring muscles through isokinetic open-kinetic-chain knee flexion and extension exercises, proprioception and dynamic joint stability training through wobble board balancing, a routine on the mini-trampoline and from the third session a functional jumping routine. the intensity of the exercises was adapted to the specific condition and ability of each subject. particular attention was given during the proprioception and joint stability training not to cause further pain as this would have caused inhibition of the stabilising muscles and therefore would have been counterproductive. the home programme included the following: stretching of the hamstrings, quadriceps/hip flexors and calf muscle groups; strengthening of the knee flexor/extensor, ankle plantar/dorsiflexor and hip flexor/extensor muscle groups by means of callisthenic type exercises that could be done without any apparatus; and proprioception done by means of the stork stand on a plank of 2.5 cm wide for 1 minute per leg. the subjects were introduced to the home programme during the second contact session. they then followed the programme on their own on different days from the contact sessions. an exercise log was kept by subjects to enhance compliance. data were analysed using descriptive statistics, t-tests and the wilcoxon signed rank test. results subjects had a mean age of 14.3 years, mean height of 1.7 m and mean weight of 59.7 kg. the mean duration of anterior knee pain for the subjects selected for the study was 16 months. although the subjects were randomly allocated to the control and experimental groups, the control group subjects were slightly older, taller and heavier than the experimental group subjects but the differences were not statistically significant (p>0.05). it was thus concluded that the control group met the criteria for comparison with the experimental in a study of this nature. table ii shows that the intervention programme resulted in a significant (p<0.01) reduction in worst, least and normal pain ratings at the post-testing, and this was maintained 1 month later at the post-post testing. there was no significant change in the control group apart from least pain, which increased significantly (p<0.05) at the post-test. the positive change in vas points for worst, least and normal pain in the experimental group at post-testing was 3.1, 1.2 and 2.3 points respectively. a change of 1.0 point on the 10 point (cm) vas is reported to be the minimum required to indicate a clinically important change. 4,9 it can therefore be assumed that the intervention programme was successful in reducing pain. subjects individually indicated particular activities on the patient specific functional scale that they were experiencing difficulty with due to their knee pain. the activities reported in order of importance were: running, jumping, stair climbing, sitting, cross-legged sitting and twisting movements. table iii shows that on completion of the intervention programme, subjects from the experimental group reported a significantly (p<0.01) improved ability to perform these same activities. this reduced disability was maintained at the post-post testing (p<0.01). no change occurred in the control group. thus it can be concluded that participation in the intervention programme resulted in decreased disability due to anterior knee pain, which was maintained in the long term. table iv shows that the subjects of the control group experienced the same or worse pain at the post-test when compared with the pre-test, while all the subjects in the experimental group indicated an improvement in their condition. most of the subjects in the experimental group reported that their condition was at least as good or better at the post-post test compared with the post-test. the results indicate that the benefits derived from the intervention programme were largely retained after the intervention was stopped. there was a significant (p<0.01) gain in muscle strength in both the quadriceps (11.5%) and hamstring (14.2%) muscle groups at the post-test and a further 1.2% in the quadriceps and 1.4% in the hamstrings at post-post test in the experimental group. no significant (p>0.05) change was found in the control group. table iii. mean ratings of ability to perform various activities as indicated on the patient-specific functional scale (psfs) at the pre, post-, and preand post-post testing of the control (n=12) and experimental (n=18) groups group pre post difference post difference pre v. post post pre v. post post control 5.7 5.6 -1.8% † n/a ±1.2 ±1.1 experimental 5.6 7.8 +39.3%* 8.2 +46.4%* ±1.4 ±1.1 ±1.2 * p<0.01 † p>0.05 pg4-20.indd 17 4/23/08 11:31:09 am 18 sajsm vol 20 no. 1 2008 table v shows a small but significant (p<0.01) improvement in quadriceps, hamstring and gastrocnemius flexibility in the experimental group at the postand post-post testing. there was no significant (p>0.05) change in the control group. table vi show a large significant (p<0.01) improvement in both proprioception and dynamic balance of the experimental group at the postand post-post testing while the control group showed little (p>0.05) change at the post-test. discussion the main purpose of this study was to determine if a specific rehabilitation programme (table i) of only 2½ weeks, which is substantially shorter than traditional programmes reported in literature, would effectively address the problem of anterior knee pain in adolescents. this approach was prompted by two factors experienced in years of private practise, namely that attendance of rehabilitation sessions declined substantially after 3 weeks, and that very good results were found with short programmes concentrating on strength, flexibility and especially neuromuscular control (dynamic proprioception). it was time to test the effectiveness of such a programme in alleviating anterior knee pain in adolescents. results of the three tests (tables ii, iii and iv) measuring the impact of anterior knee pain on subjects and on their ability to function optimally clearly prove the success of the intervention programme. subjects in the experimental group reported a substantial and significant (p<0.01) reduction in worst (43%), least (35%) and normal (42%) pain as measured on the visual analogue scale while subjects in the control group reported nonsignificant (p>0.05) changes for worst (3%) and normal (0%) pain but a significant (p<0.05) increase (20%) in least pain (table ii). the experimental group subjects reported substantial (39%) and significant (p<0.01) improvement in their ability to perform various activities as measured on the patient specific functional scale (table iii) while the control group deteriorated slightly (2%) but not significantly (p>0.05). of the experimental group 33% of subjects reported ‘great improvement’ and 67% ‘improvement’ table iv. percentage change in condition in the control (n=12) and experimental (n=18) groups as measured by the scale for change in condition between the preand post-, and post and post-post tests comparison great improve no deterio not improvement ment change ration tested (%) (%) (%) (%) (%) control group (n=12) 0.0 0.0 75 25 pre v. post experimental (n=18) 33.3 66.7 0.0 0.0 pre v. post experimental (n=18) post v. 27.8 27.8 11.1 16.7 16.7 post-post table v. percentage difference in mean muscle flexibility (degrees) of the control (n=12) and experimental (n=18) groups between the preand post-, and preand post-post testing. data are expressed as the mean ± sd. group quadri quadri ham hams gastroc gastrocand ceps ceps strings trings nemius nemius pre side pre v. post pre v. pre v. post pre v. pre v. post v. post-post post-post post-post control 65.9±9.6 v. n/a 57.4 ±7.7 v. n/a 67.8±4.8 v. n/a right 65.8±9.4 57.5± 7.8 67.8±4.7 % change -0.2% † +0.2% † 0% † control left 62.6±10.3 v. n/a 58.0±5.5 v. n/a 69.6±6.2 v. n/a 62.8±8.8 58.1±4.8 69.4±8.3 % change +0.3% † +0.2% † -0.3% † exp. right 68.2±12.1 v. 68.2±12.1v. 57.7 ±8.3v. 57.7±8.3 v. 66.7±3.8 v. 66.7±3.8v. 70.7±7.7 70.5±9.8 59.5±5.6 59.5±4.2 68.7±5.8 69.2±6.2 % change +3.7%* +3.4%* +3.1%* +3.1%* +3.0%* +3.7%* exp. left 66.1 v. 69.0 66.1 v. 68.8 56.5 v. 57.9 56.5 v. 58.8 66.8 v. 68.3 66.8 v. 68.3 ±10.8 v. 8.9 ±10.8 v. 7.5 ±8.0 v. 6.5 ±8.0 v. 9.2 ±6.0 v. 3.8 ±6.0 v. 4.4 % change +4.4%* +4.1%* +2.5%* +4.1%* +2.2%* +2.2%* * p < 0.01 † p>0.05 pg4-20.indd 18 4/23/08 11:31:10 am sajsm vol 20 no. 1 2008 1� as measured on the scale for change in condition while 75% of the control group reported ‘no change’ and 25% a ‘deterioration’ (table iv). after completing the rehabilitation programme subjects of the experimental group thus clearly experienced less pain, were able to perform activities which gave them problems before the intervention better, and perceived the anterior knee pain to have subsided substantially. from the subjects’ point of view the rehabilitation programme was therefore a success. in order for any programme, especially a programme of short duration, to be successful the benefits achieved must have a lasting effect once the programme is stopped. the results in tables ii and iii, which compare the vas and psfs scores of the subjects before the start of the programme with those 1 month after cessation of the programme, indicate no deterioration and in some of the tests a further improvement. least pain decreased a further 2% and the psfs increased a further 8%. the ‘change in condition’ results as shown in table iv, which compares the condition of the subjects at the cessation of the programme with 1 month later, substantiate this further improvement. when the subjects (17%) who failed to complete the post-post test were excluded from the calculation, the remaining subjects reported a further ‘great improvement’ of 33%, an ‘improvement’ of 33%, a ‘no change’ of 13% and a ‘deterioration’ of 20%. the additional improvement experienced after the intervention programme was stopped can probably be attributed to improved neuromuscular control, which will be described further on. strength or, more accurately, the ability of the muscles of the knee to contract strongly when required should play an important role in alleviating anterior knee pain. after completion of the intervention programme the subjects of the experimental group were significantly (p<0.01) stronger in the quadriceps and hamstrings. the control group was slightly weaker in the post than in the pre-test. however, it is not clear if the improvement in strength is a cause for, or an effect of, the improvement in the condition (anterior knee pain). clearly, inhibition of muscles of the knee caused by anterior knee pain would have precluded subjects from being able to apply full force during the pre-tests. either way the rehabilitation programme resulted in greater force and thereby greater knee stability. due to the limited exposure to stretching exercises, which were only included in the home programme for the experimental group, large changes were not expected. small but significant (p<0.01) improvements were recorded in the quadriceps (4%), hamstrings (3%) and gastrocnemius (3%) flexibility for the experimental group (table v). the control group did not show any change in flexibility. it is not clear if these improvements in flexibility were sufficient to have contributed to an improvement in the condition of anterior knee pain. proprioception is traditionally defined as the ability to determine the position of a joint in space at any given instant. the focus of the present study, however, was on proprioception as it relates to neuromuscular control and joint function. table iv shows the results for the willknox wobble board test, which was used as a measure of proprioception and the bass test, which was used to measure dynamic balance. after conclusion of the intervention programme the experimental group showed a substantial (46%) and significant (p<0.01) reduction in time unbalanced on the wobble board while the control group only showed a small (3%) but non-significant (p>0.05) improvement. the bass test showed a large (38%) significant (p<0.01) improvement in the experimental group but only a small (3%) non-significant (p>0.05) improvement in the control group. the improvement in the experimental group further increased to 51% (willknox wobble board) and 53% (bass test) at the post-post test 1 month after the intervention programme was concluded. good results in the willknox wobble board test and the bass test are dependent on proper neuromuscular control of the lower limb joints, especially the knee joint. the results of the present study could imply that restoration of proper neuromuscular control through proprioceptive and dynamic balance exercises probably played a major role in alleviating the symptoms of anterior knee pain in the subjects of the experimental group. an integrated relationship exists between proprioception, neuromuscular control and dynamic joint stability. 14,20 improvement in neuromuscular control helps to reduce inhibition caused by pain and instability in the knee joint, thus allowing the muscles to contract optimally and support the knee better. if pain is present it results in involuntary inhibition, whereby the patient is unwilling to maximally contract the muscles due to the pain or the fear of pain. 18 reflex inhibition is a limiting factor in rehabilitation as it restricts full muscle activation, thus preventing restoration of muscle strength. 15 once the pain table vi. percentage difference in performance in the willknox wobble board test (proprioception) and bass test (dynamic balance) of the control group (n=12) and experimental group (n=18) between the preand post-, and preand post-post tests group wobble board wobble board bass test (seconds) (seconds) bass test pre pre v. post pre v. post pre v. post-post v. post post control 32.2 ±13.4 v. n/a 56.4±15.1 v. n/a 31.1 ± 8.9 58.3 ±14.6 % change -3.4% † +3.4% † experimental 30.3 ±13.5 v. 30.3 ±13.5 v. 47.7 ±17.4 v. 47.7±17.4v. 16.4±7.2 14.9±7.9 65.6±12.8 73.1±13.0 % change -45.9%* -50.8%* +37.5%* +53.2%* * p<0.01 †p>0.05 pg4-20.indd 19 4/23/08 11:31:11 am 20 sajsm vol 20 no. 1 2008 inhibition is sufficiently removed the muscles increasingly fulfill their roles in joint stability and further improvement takes place spontaneously during normal daily use of the joint. barrett 1 went so far as to suggest that proprioception is a greater contributor to normal limb function during activity than muscle strength, which is a statement the current authors agree with. the restoration of proprioception and neuromuscular control is essential in a comprehensive conservative rehabilitation programme. 14 the current rehabilitation programme could have been successful in re-establishing this neuromuscular control because the activities employed progressively forced the subjects to exercise at the boundary of neuromuscular control but never crossing the line where pain results in the loss of control. limitations possible limitations of this study were the lack of a placebo treatment in the control group and the absence of blinding procedures. due to insufficient resources and for the sake of accuracy in treatment and testing, both researchers were involved in all the protocols. all possible precautions were taken to ensure reliability of the data. conclusion the rehabilitation programme shown in table i, complemented by the home programme as described in the methods section, has been shown to effectively address anterior knee pain in adolescents. although not directly proven in this study, restoration of neuromuscular control is probably the main contributing factor for the reduction in anterior knee pain. the study also demonstrated good retention of improvements and even further improvement after cessation of the programme. this may be attributed to the ability of subjects to resume active participation in physical activities previously affected by the condition. advantages of this particular programme is that good results can be effected in 5 sessions over 2½ weeks and that patients are familiarised with a home programme which they know works and which they are likely to continue with. practical implications this study provides an exercise regimen that successfully addresses knee pain in adolescents. the harmful effects of forced inactivity on the physical development of children can be avoided by following this programme. acknowledgements this study was supported financially by the university of zululand, south africa. references 1. barrett ds. proprioception and function after anterior cruciate ligament reconstruction. j bone joint surg br 1991; 73: 833-7. 2. bosco js, gustafson wf. measurement and evaluation in physical education, fitness, and sports. new jersey: prentice-hall, 1983. 3. chatman ab, hyams sp, neel jm, et al. the patient-specific functional scale: measurement properties in patients with knee dysfunction. phys ther 1997; 77(8): 820-9. 4. crossley k, bennell k, green s, cowan s, mcconnell j. physical therapy for patello-femoral pain: a randomized, double-blinded, placebo-controlled trial. am j sports med 2000; 30(6): 857-65. 5. cutbill jw, ladly ko, bray rc, thorne p, verhoef m. anterior knee pain: a review. clin j sport med 1997; 7: 40-5. 6. difiori jp. overuse injuries in children and adolescents. the physician and sports medicine 1999; 27(1): 75-89. 7. dugan sa. sports-related knee injuries in female athletes. what gives? am j phys med rehabil 2005; 84(2): 122-9. 8. galanty hl, matthews c, hergenroeder ac. anterior knee pain in adolescents. clin j sport med 1994; 4: 176-81. 9. harrison e, quinney h, magee d, sheppard ms, mcquarrie a. analysis of outcome measures used in the study of patello-femoral pain syndrome. physiother can 1995; 47(4): 264-72. 10. harvey d. assessment of the flexibility of elite athletes using the modified thomas test. br j sports med 1998; 32: 68-70. 11. jolles bm, buchbinder r, beaton de. a study compared nine patientspecific indices for musculoskeletal disorders. j clin epidemiol 2005; 58: 791-801. 12. kane rl, bershadsky b, rockwood t, saleh k, islam nc. visual analog scale reporting was standardized. j clin epidemiol 2005; 58: 618-23. 13. karlsson j, thomee r, sward l. eleven-year follow-up of patello-femoral pain syndrome. clin j sport med 1996; 6: 22-6. 14. lephart sm, pincivero dm, rozzi sl. proprioception of the ankle and knee. sports med 1998; 25(3): 149-55. 15. palmieri rm, ingersoll cd, edwards je, et al. arthrogenic muscle inhibition is not present in the limb contralateral to a simulated knee joint effusion. am j phys med rehabil 2003; 82(12): 910-6. 16. patel dr, nelson tl. sports injuries in adolescents. med clin north am 2000; 84(4): 983-1005. 17. pollock d. clinical examination of the patello-femoral joint. sa orthop j 2004; 3(4): 8-10. 18. powers cm, landel r, perry j. timing and intensity of vastus muscle activity during functional activities in subjects with and without patello-femoral pain. phys ther 1996; 76(9): 946-67. 19. rogan im. anterior knee pain in the sporting population: forum. sa bone and joint surg 1995; 5(2): 28-30. 20 sharma l. proprioceptive impairment in knee osteoarthritis. rheum dis clin north am 1999; 25(2): 299-314. 21. shea kg, pfeiffer r, curtin m. idiopathic anterior knee pain in adolescents. orthop clin north am 2003; 34(3): 377-83. 22. shelton gl, thigpen lk. rehabilitation of patello-femoral dysfunction: a review of literature. j orthop sports phys ther 1991; 14(6): 243-9. 23. souza dr, gross mt. comparison of vastus medialis obliquus: vastus lateralis muscle integrated electromyographic ratios between healthy subjects and patients with patello-femoral pain. phys ther 1991; 71(4): 31020. 24. stanitski cl. anterior knee pain syndromes in the adolescent. j bone joint surg br 1993; 75(9): 1407-16. 25. stratford pw, kennedy dm, hanna se. condition-specific western ontario mcmaster osteoarthritis index was not superior to region-specific lower extremity functional scale in detecting change. j clin epidemiol 2004; 57: 1025-32. 26. thomee r. a comprehensive treatment approach for patello-femoral pain syndrome in young women. phys ther 1997; 77(12): 1690-703. 27. thomee r, augustsson j, karlsson j. patello-femoral pain syndrome: a review of current issues. sports med 1999; 28(4): 245-62. 28. tria aj, palumbo rc, alicea ja. conservative care for patello-femoral care. orthop clin north am 1992; 23(4): 545-54. 29. witvrouw e, lysens r, bellemans j, peers k, vanderstraeten g. open versus closed kinetic chain exercises for patello-femoral pain. am j sports med 2000; 28(5): 687-94. pg4-20.indd 20 4/23/08 11:31:12 am original research sajsm vol 23 no. 4 2011 103 introduction the south african rugby union (saru) hosts four national competition tournaments for junior players (13 18 years of age) each year. these tournaments are designed to be the pinnacle of saru’s talent identification and development programme. 1 the national tournaments are divided into three age groups, u13 craven week, u16 grant khomo week and u18 craven week and academy week. the reason for the first national schools tournament in july 1964 was to bring the top high school boys together to celebrate the 75th anniversary of the south african rugby board. the tournament was named after the famous springbok rugby player and coach dr danie craven. the u18 tournament has been held annually since then and is currently rated as one of the top school-boy rugby tournaments in the world. 2 the tournament has a reputation for identifying and developing talent in south africa, supported by the fact that several springboks played in the tournament as schoolboys. 3 to understand the context of these age group tournaments in relation to talent identification, it is necessary to firstly define this term, as there is currently no consensus on the definition of either talent identification (tid) or talent development (tde). therefore for the purpose of this paper the definition used in a recent review of talent identification and development models in sport will be used (p. 403): ‘process of recognising current participants with the potential to excel in a particular sport’ 4 and tde is described as ‘providing the most appropriate learning environment to realise this potential’. 4 the first systematic talent identification and development programmes were implemented by the communist countries in the 1960s and 70s. 5 other countries, such as china and australia, used substantial state resources to fund tid and tde programmes in the 1980 and 1990s. 6 these programmes have created the perception held by many parents, coaches and administrators that talented adolescent athletes can be detected or identified by measuring those characteristics that predict success in adult competition. this traditional view has been contradicted in the scientific literature where erroneous assumptions and problems have been identified. 4,5 for example, the main problem with this model is that most talent identification programmes are directed at the adolescent age group (13 18 years), an age which is characterised by much variation as a result of different rates of development. 5 furthermore, talent is not simply the measurement of innate abilities, but results from the interaction of these innate abilities with the environment within which the athlete develops. 4 for these reasons the traditional models, popularised in the 1980s and 1990s, are now being challenged. this has resulted in a general shift towards athlete development rather than talent identification. the model that best encapsulates this shift is the long term athlete development model (ltad). 7 this model was developed by istvan balyi 7 and describes the different stages of physical, mental, emotional and cognitive development of children and adolescents. the main emphasis of this model is to provide more time and opportunities for athletes to develop, especially those athletes who mature at a later stage. in addition, this model provides guidelines on the types of activities related to talent identification and skill acquisition that are appropriate at the different age groups. the ltad model provides a framework within which each sport discipline can create an athlete development pathway catering for the demands of that sport. abstract background. the south african rugby union has adopted the model of competition at a young age (u13 years) to identify talent. there is concern however that bigger players who mature early are selected at this age, and that the majority of these players do not play rugby at a high level after puberty. objectives. the aim of this study was to establish how many players in the 2005 u13 craven week (n=349) participated in subsequent u16 grant khomo and u18 craven week tournaments. design. longitudinal. results. 31.5% of the players who played in the u13 craven week, were again selected to play at u16 grant khomo week and 24.1% were selected for the u18 craven week. conclusion. seventy-six per cent of the players selected for the u13 tournament do not play at the u18 national craven week tournament. these data need to be considered when decisions are made about the cost-effectiveness of staging the u13 tournament, particularly if the main goal of this tournament is for talent identification. justin durandt1 bsc (med)(hons) exercise science (biokinetics) ziyaad parker2 bsc (med)(hons) exercise science (biokinetics) herman masimla3 (ba, hde) mike lambert2 (phd) 1 discovery health high performance centre, sports science institute of south africa, newlands, cape town, south africa 2 mrc/uct research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, south africa 3 south african rugby union, newlands, cape town, south africa correspondence to: justin durandt (jdurandt@ssisa.com) rugby-playing history at the national u13 level and subsequent participation at the national u16 and u18 rugby tournaments 104 sajsm vol 23 no. 4 2011 early research on talent identification of young rugby players (8 13 years) in south africa showed that talented players could be identified at an early age. 8 however, this study and a subsequent follow-up study did not track whether these talented young players developed into older talented players, particularly after they had matured through puberty (13 18 years). 9 in a recent commentary we show how south africa has 9.4 and 3.7 times as many pre-teen players compared with australia and new zealand respectively, yet at a senior level south africa has only 3.1 and 2.3 times as many players as australia and new zealand. 10 it may be argued that saru has to place less emphasis on organised talent identification as there is such a large pool of pre-teen players (n=239 614). 11 with such a large pool of players, the precision and efficiency of the system becomes less important because the expectation is that the talented players will emerge as a result of the competition. it follows that saru has adopted the approach of organised competition as its main source of talent identification and development. with this approach, and the strong competition between rugby-playing schools, the chances of talented players emerging are very good. however, this approach might also account for the large attrition of players from pre-teens to seniors observed in south africa, but not in a country such as australia which places less emphasis on competition at these young ages. 12 in contrast to the competitive model for young players, adopted by saru, most experts agree that promoting participation should take precedence over competition at a young age. 13 particularly at the u13 level players have different maturation ages. therefore there is a bias for the coaches to select the bigger boys who may be more mature, but not necessarily more talented. there have been discussions about changing the format of the national u13 tournament and to rather use the resources for activities aimed at player retention and participation (personal communication: m green, saru development manager). one of the problems saru has had in making these decisions is that there is no hard evidence supporting either side of the argument. therefore the aim of the study was to provide objective data to determine how many boys who played at a u13 national tournament went on to play at the u16 grant khomo and u18 craven week tournaments. we hypothesised that the representation of the u13 players in the older groups would get progressively lower because the factors which determine performance in rugby at an u18 level are not evident at the u13 level and only partially developed by 16 years of age. methods the study was conducted in the form of a survey and was retrospective in nature. the 2005 u13 craven week list of players from the saru database was used for analysis. the year 2005 was selected as this was the first year that all the names of all players attending the week were entered into an electronic database. these names were checked against all the names of all the players attending the u16 grant khomo or the u18 craven week tournaments between 2006 and 2010, using the saru database. the names were manually sorted to determine representation of the players over the duration of the study. this manual process was checked using the ‘vlookup’ and ‘match’ functions in excel. permission to use the data from the database was obtained from the faculty of health sciences research and ethics committee of the university of cape town. results sixteen teams attended the 2005 u13 craven week. each team was permitted to have 22 players (n=352). however, the actual number of players listed on the saru database was n=349 as a result of three teams only having 21 players listed. fig. 1 shows that one 2005 u13 player (0.3%) participated in the u16 grant khomo tournament in 2006, five players (1.4%) participated in 2007 and 107 players (30.7%) participated in 2008. the results show that the players had a greater representation in the u16 tournament as their age increased from u14 to u16 over three successive years. fig. 2 shows that in total 110 (31.5%) players who played u13 craven week were selected for u16 craven week in 2006 2008. the totals in fig. 2 are less than the totals in fig. 1 because 3 players from 2007 also participated in 2008. as a result of them participating for 2 years in succession they were not counted as repeats in the total. fig. 1 also shows that two players (0.6%) from the u13 tournament participated in the u18 craven week in 2008, 36 players (10.3%) participated in 2009 and 77 players (22.1%) participated in 2010. fig. 1. number of players from the 2005 u13 tournament who played at subsequent u16 grant khomo and u18 craven week tournaments. the data are expressed as a percentage of the 2005 u13 tournament (n=349). fig. 2. the total number (and per cent) of the players from the 2005 u13 tournament who played at the u16 grant khomo and u18 craven week tournaments. sajsm vol 23 no. 4 2011 105 as expected, the number of players participating increased as the players got older. fig. 2 shows that 84 players (24.1%) of the 2005 u13 craven week players played at the u18 tournament between 2008 and 2010. only six of the u18 players who played in 2009 did not play in 2010 and only one of the two players who played u18 in 2008 also played in 2009. therefore there were a total of 84 players if the non-repeats were added to the 2010 total. the representation decreased by 7.4% from u16 (31.5%) to u18 (24.1%). discussion the main finding of this study was that the majority of players from the 2005 u13 craven week were not selected for either the u16 (69%) or the u18 craven week tournament (76%) a few years later. these results can be interpreted in one of two ways. firstly, the attributes that determined success at the u13 level had changed at the u16 and u18 level. a number of studies have measured players of various ages to identify key physiological characteristics associated with performance in rugby. 14-16 these include body size, aerobic capacity, muscular strength and endurance, speed and muscle power. there is no evidence that the contribution to performance of these key physiological characteristics change with player age, and therefore this explanation cannot account for the poor conversion of success at the u13 level to success at the u16 and u18 levels. an alternative interpretation is that the u13 players had characteristics associated with success in rugby, but these characteristics changed as the players got older. this is a more likely explanation, particularly since the span from 13 to 18 years encompasses puberty and maturation. it follows that more mature players of the same chronological age (u13) will have an older biological age. these players are more likely to be bigger, faster and stronger 17 and as a result of these characteristics will perform better than players who are less biologically mature. the late maturers who are talented will not be selected at this age (u13) and may only be selected at a high level after they have matured (u16 or u18). some of these players may also choose to participate in another sport in which they can excel. 18 the latter scenario could account for the major attrition that occurs in south african rugby. 10 these results support the current consensus in the scientific literature that describes the complexities in identifying talent in early adolescence. 5 a recent editorial stated that ‘the prediction of long term success is extremely difficult and the later successful athletes are not necessarily the ones who performed best in youth competitions’ (p.683). 19 this is especially true in sports, such as rugby, where body size is related to performance. 18,20 what practical steps can be taken to address this problem? the first step is to acknowledge that talent identification is a complex process achieved by a combination of physical attributes, skills, attitudes and behaviours. 20 the next step is to adopt a more pragmatic approach to develop talent from a young age. macnamara and colins 20 highlight the fact that many talent identification programmes operate in resource-challenged environments and that this necessitates the need to establish sports policy against strong evidence-based research. this is true of the south african environment where any programme needs to increase general participation levels and the quality of this participation, while at the same time having clear pathways to elite participation. in summary, these results suggest that talented young players (u13) do not necessarily become talented older players (u16 and u18). the emphasis placed on talent identification at the young level (u13) may be associated with the high attrition in participation from pre-teen to teens and then senior level in south african rugby. 10 changes need to be made to the ltad programme of saru considering these data in the revised plan. references 1. south african rugby union. background to the south african rugby football union (sarfu) and sa rugby (pty) limited. http://www.sarugby. co.za. 2. rugby365. craven week history. website 2009. http://www.rugby365.com. 3. colquhoun a, grieb e, heath d. sa rugby annual 2009. 38th ed. ctp books: parow, cape town, 2009. 4. vaeyens r, lenoir m, williams am, philippaerts rm. talent identification and development programmes in sport: current models and future directions. sports med 2008;38(9):703-714. 5. pearson dt, naughton ga, torode m. predictability of physiological testing and the role of maturation in talent identification for adolescent team sports. j sci med sport 2006;9:277-287. 6. digel h. the context of talent identification and promotion: a comparison of nations. new studies in athletics 2002;17:13-26. 7. balyi i, way r, cardinal c, higgs c. canadian sport for life: long term athlete development resource paper. vancouver bc: canadian sport centres, 2007. 8. pienaar ae, spamer mj. a longitudinal study of talented young rugby players as regards their skills, physical and motor abilities and anthropometric data. j hum mov stud 1998;34:013-032. 9. spaamer ej, hare ea. a longitudinal study of talented rugby players with special reference to skill, growth and development. j hum mov stud 2001b;41:39-57. 10. lambert mi, durandt jj. long-term player development in rugby ─ how are we doing in south africa? south afr j sports med 2010;22:67-68. 11. international rugby board. website 2010 http//www.irb.com/unions/unions=11000034/index.html. 12. australian rugby union. kids rugby. website 2011 http://www.rugby.com. au/tryrugby/kidsrugby. 13. way r, balyi i. competition is a good servant, but a poor master. vancouver bc: canadian sport centres, 2007. 14. deutsch mu, maw gj, jenkins d, reaburn p. heart rate, blood lactate and kinematic data of elite colts (under-19) rugby union players during competition. j sports sci 1998;16:561-570. 15. durandt jj, du toit s, borresen j, et al. fitness and body composition profiling of elite junior south african rugby players. s afr j sports med 2006;18:38-45. 16. spamer ej. talent identification and development in youth rugby players: a research review. s afr j res sport, phys ed and recreat 2009;31:109118. 17. figueiredo aj, goncalves ce, coelho e silva mj, malina rm. characteristics of youth soccer players who drop out, pesist or move up. j sport sci 2009;27(9):883-891. 18. malina rm, pene reyes me, eisenmann jc, horta l, rodrigues j, miller r. height, mass and skeletal maturity of elite portugese soccer players aged 11-16 years. j sport sci 2000;18:685-693. 19. elferink-gemser mt, jordet g, coelho-e-silva mj, visscher c. the marvels of elite sports: how to get there? br j sports med 2011;45(9):683-684. 20. coelho-e-silva mj, moreira ch, concalves ce. growth, maturation, functional capacities and sport specific skills in 12-13 year old basketball players. j sports med phys fitness 2010;50:74-181. 21. macnamara a, collins d. comments on ‘talent identification and promotion programmes of olympic athletes’. j sport sci 2011;29(12):1353-1356. pg88-94.indd introduction concussion is a trauma-induced change in mental state that may or may not involve loss of consciousness. 1 it is a form of mild traumatic brain injury. the injury may manifest with any combination of physical, cognitive, emotional and sleep-related symptom clusters including headache, dizziness, nausea, visual disturbances, amnesia, poor concentration, irritability, depressed affect, fatigue and drowsiness (table i). concussion is common in rugby football in south africa and has been cited as being amongst the three most common rugby injuries, with the tackle being associated with the highest incidence. 2 the incidence of concussion at high school level has been reported as 21.5%. 3 in another study, the prevalence of concussion was reported as high as 50% in schoolboy rugby players, as the majority of mild head injuries are often not recognised and reported in this age group. 4 a similar prevalence has been noted in adult rugby players. 5 in the 1999 super 12 rugby competition, the incidence of concussion was reported as 20%, the most common injury for that competition. 6 scientific research into many aspects of concussion has been impaired as much by differences in definition as by the ethical and practical issues involved in inducing and monitoring brain injury. 1 from this has stemmed controversy regarding the ideal management of concussion in sport and a lack of objective data guiding return-to-play decisions, 1 resulting in sports organisations review sports-related concussion relevant to the south african rugby environment – a review abstract guidelines for returning a concussed player to sport had been somewhat controversial and nebulous until the emergence of a series of international consensus meetings and statements initiated in 2001. the vienna (2001), prague (2004) and zurich (2009) statements as well as the american national athletic trainers association (2004) and the american college of sports medicine (2005) position stands have given all clinicians better guidance that is more evidence-based than the somewhat subjective guidelines of the latter 20th century. some impetus to research and the re-evaluation of assessment and management guidelines has been provided by the emergence of computerised neuropsychological test batteries as a useful barometer of cognitive recovery. however, the clinical evaluation of a concussed player remains the cornerstone of management and should incorporate a thorough symptom analysis, general, cognitive and neurological examination, and balance testing. the sports concussion assessment tool (scat) 2 card is a clinical evaluation tool intended to summarise the most significant aspects of clinical assessment. in addition, and as an essential ‘final stress’ test, the athlete must be subjected to a series of graded exercise sessions, increasing in severity, before being returned to contact or collision sport. a structured clinical evaluation is particularly important in the south african context, where computerised testing may not be accessible to many. this article serves to collate and highlight the evidence-based and consensus data available for management of the concussed rugby player in 2010. correspondence: dr jon patricios morningside sports medicine po box 1267 2121 parklands tel: +27 11 883 9000 fax: +27 11 282 5165 e-mail: jpat@mweb.co.za j s patricios (mb bch, mmed (sci), facsm, ffsem (uk))1 r m n kohler (mb chb, mphil, facsm)2 r m collins (mb bch, msc (sports med))3 1 dr patricios is a sports physician in johannesburg, director of sports concussion south africa, a consultant to the south african rugby union and an extraordinary lecturer in the department of sports medicine, university of pretoria 2 dr kohler is a sports physician at the australian institute of sport and previously chief medical officer of the western province rugby union and stormers super 14 rugby 3 dr collins is a sports physician in private practice in johannesburg and a lecturer in the department of sports medicine, university of pretoria table i. symptoms and signs of concussion1 physical cognitive emotional sleep headache dizziness blurred vision photophobia phonophobia nausea numbness/tingling vomiting fatigue visual changes balance problems poor concentration difficulty remembering feeling ‘foggy’ feeling ‘slowed down’ depression irritability mood swings aggressiveness drowsiness insomnia sleeping more difficulty getting to sleep 88 sajsm vol 22 no. 4 2010 relying on broad, subjective guidelines for head injury management and applying rigid, compulsory exclusion periods from sport depending on unvalidated grading systems of injury severity. the last 10 years have seen a more collated approach to head injury management in sports persons. the watershed occurred at the first international conference on concussion in sport, vienna 2001. 1 during this conference, a comprehensive systematic approach to concussion was formulated for application in sport, which included computer-based neuropsychological testing as an integral part of a comprehensive clinical concussion evaluation. 1 since then consolidation of the vienna guidelines has taken place at the second international conference on concussion in sport (prague 2004), 7 and the national athletic trainers association (usa, 2004) 8 and the american college of sports medicine (2005) 9 have published clinical management guidelines based on these consensus meetings. the third international conference on concussion in sport (zurich, 2008), 10 which included a submission by south african rugby, 11 is the most recent consensus meeting from which emerged the most comprehensive paper and evidence-based guidelines to date. pathophysiology the precise pathophysiology of concussion is unknown. research has shown that moderate to severe brain injury causes a complex cascade of neurochemical changes in the brain. 12 the assumption is that similar changes occur in concussion. immediately after biomechanical injury to the brain, abrupt, indiscriminant release of neurotransmitters and unchecked ionic fluxes occur. the binding of excitatory transmitters, such as glutamate, to the n-methyl-d-aspartate (nmda) receptor leads to further neuronal depolarisation with efflux of potassium and influx of calcium. these ionic shifts lead to acute and subacute changes in cellular physiology. acutely, in an effort to restore the neuronal membrane potential, the sodium-potassium (na1-k1) pump works overtime. the na1-k1 pump requires increasing amounts of adenosine triphosphate (atp), triggering a significant increase in glucose metabolism. this ‘hypermetabolism’ occurs in the setting of diminished cerebral blood flow, and the disparity between glucose supply and demand produces a cellular energy crisis. the resulting energy crisis or ‘mismatch’ may account for the symptoms and behavioural changes (table i) as well as being a likely mechanism for post-concussive vulnerability, making the brain less able to respond adequately to a second injury and potentially leading to longer-lasting deficits. loss of consciousness that may occur with concussion is likely due to damage to the reticular activating system. the reticular activating system recovers relatively quickly and therefore consciousness is regained fairly soon after injury. 13 the biochemical mismatch lasts significantly longer, making loss of consciousness a poor indicator of severity of injury. potential complications of concussion early complications intracranial space-occupying lesions concussion may be, but is not usually, associated with damage to cerebral arteries and veins. bleeding from these vessels may lead to epidural, subdural or intracerebral haematomas. 14 signs of raised intracranial pressure have to be recognised immediately and treated surgically to decompress the brain. there may be considerable overlap between the initial clinical presentation of a concussed athlete and that of a player who has an intracranial bleed, stressing the need for ongoing monitoring of the head-injured patient in the first 48 72 hours after injury. second-impact syndrome diffuse cerebral swelling is a rare but well-recognised complication of minor head injury and occurs mainly in children and teenagers. 15 second-impact syndrome was first reported in american football players who died after relatively minor head injury. 16 this injury may occur if a player returns to play prematurely following a previous head injury. brain oedema and an increased vulnerability to injury during the biochemical ‘mismatch’ described earlier may still be present from the previous blow. a second blow results in further swelling, followed by loss of the brain’s ability to control blood inflow (autoregulation). cerebral blood flow increases rapidly and brain pressure rises uncontrollably, leading to cardiorespiratory failure and possible death. 17 impact convulsions convulsions (seizures) in collision sports are not common, but can appear as a dramatic event. 18 they characteristically occur within 2 seconds of impact, but are not necessarily associated with structural brain damage. 19 the good outcome with these episodes and the absence of long-term cognitive damage reflect the benign nature of these episodes, not requiring anti-epileptic treatment and prolonged preclusion from contact sports. 19 late complications post-concussion syndrome the clusters of symptoms manifesting after a concussive blow may persist for days to weeks, being debilitating and disturbing to the patient. 1 the consequences of symptoms such as headache, dizziness, memory loss and fatigue are particularly significant in young people who may be in a learning environment, making decisions concerning rest from cognitive as well as physical stresses important. education about the diagnosis and reassurance that the symptoms will disappear are important to reduce the anxiety that patients experience. involving social support is very beneficial. chronic traumatic encephalopathy this condition reflects the cumulative effect of long-term exposure to repeated concussive and sub-concussive blows. 20 certainly there is growing concern that each episode of concussion may result in residual brain damage possibly associated with cerebral deposition of the abnormal tau protein. 21 this is most evident in the development of cognitive dysfunction in boxing, the degree of which is directly related to the number of bouts in a boxer’s career. 22 the cerebral damage that may occur in rugby players is thought to be largely cortical and more subtle than the cerebellar and basal ganglia manifestations of dementia pugilistica. cognitive deficits have also been documented in amateur, professional and retired soccer players. 23 genetic factors, associated with the apoe4 gene, may also increase the risk of developing chronic brain injury in sport. 24 future research will need to establish what severity of head injury causes summation and how long that residual effect may last. 1 thus, it would be responsible to want to document players’ cognitive function periodically and note whether any cognitive deficit is present over time. risk of a second concussion players with a past history of concussion may be at increased risk of subsequent concussion. 25 however, this remains controversial and it seems that certain players display a high-risk playing technique (tackling head-on) that places them at increased risk of concussion. the risk of concussion is a feature of any collision sport and is directly related to the amount of time spent actually playing the sport. therefore, the chance of repeat concussion may reflect the level of exposure to injury risk. sajsm vol 22 no. 4 2010 89 90 sajsm vol 22 no. 4 2010 concussion grading the grading of the severity of concussion is controversial. at least 16 different classification systems for head injury severity have been described. 25 all except the glasgow coma scale, designed for the assessment of severe head trauma, are based on anecdotal evidence and not scientifically validated. the two most commonly used grading systems in sport have been the cantu and colorado guidelines (table ii). 26,27 however, there are a number of practical difficulties with concussion scales. firstly, it may be impossible to be certain that loss of consciousness has occurred as it may be momentary and by the time the medical attendant reaches the player, the player may appear only dazed. secondly, there are also inconsistencies between these scales in terms of return-to-play guidelines. a first-time concussion associated with a loss of consciousness for less than 5 minutes correlates with a cantu grade 2 injury and results in the player missing 1 week of play. the same injury correlates with a colorado grade 3 injury and the player is rested for a minimum of 1 month. this may result in coaches and team physicians utilising the injury scale that suits their needs but which may not be the best medical management for the player. also, as mentioned earlier, loss of consciousness is a poor prognostic indicator. cognitive (thinking) impairment may be as severe in an athlete who has lost consciousness compared with an athlete who has not. therefore basing return-to-play decisions on the presence of loss of consciousness is inaccurate. moreover, posttraumatic amnesia can only be determined retrospectively and is of little use for the on-field evaluation. the concept of traditional mandatory exclusion periods based on the above injury grading is not helpful and is based on data from motor vehicle accidents. 28 the lack of validity of grading systems in a sporting milieu has lead to a move away from such dogmatic guidelines to a more individualised approach. prevention of concussion the brain is not an organ that can be trained to withstand injury, therefore extrinsic means of injury prevention need to be sought. the use of protective equipment has been advocated to reduce the risk of concussion in rugby. recent evidence for the use of international rugby board-approved headgear for the prevention of concussion disputes its effectiveness. 29 interestingly, rugby players believed that wearing headgear did prevent concussion, yet very few reported wearing headgear. evidence for the use of mouthguards as a preventive aid is inconclusive but they are advocated for the prevention of oral and dental injuries. 30 it is postulated that dentally-fitted mouthguards may decrease forces transmitted to the brain via absorption of impacts to the mandible, distraction of the temporomandibular joint and tensing of the neck muscles from biting down on the guard, resulting in decreased acceleration of the cranium on the neck. it has also been suggested that strengthening and conditioning of the neck muscles together with rule changes may reduce the incidence of concussion. 26 again, further research data are needed. clinical approach to head injury management the international concussion consensus statements largely concur that an approach to the concussed athlete incorporate the following important aspects: 1 • serial clinical history and examination • neuropsychological testing • neuroimaging – when indicated • education • prevention • future research • medicolegal considerations. any regional or national concussion initiative should therefore address these important areas. chronological approach to the clinical management of the concussed player preparedness even before a head injury occurs, medical personnel associated with contact and collision sports should ensure that: • medical and paramedical personnel present are well versed in international concussion management guidelines • ambulances are on site or easily accessible • a hospital with neuroimaging facilities and an on-call neurosurgeon is available and aware of the referral process • the minimum head and neck stabilisation equipment (spine board, cervical collar, head blocks, spider harness) is available • printed forms of appropriate concussion documentation are available: • fieldside scat cards • scat2 forms • patient advice sheets • medical certificates. coaches and referees should also ensure that they have their boksmart concussion guide tool or pocket scat card on hand at all times. on many occasions and at most practices, there are few or no medical staff available on field-side, and there should be no excuse for not being able to recognise a suspected concussion. table ii. previous severity of concussion classification and return-to-play recommendations26,27 grade return-to-play recommendation cantu guidelines 26 colorado guidelines 27 grade 1 (mild) may return to play when asymptomatic no loc* pta** <30 min confusion, no amnesia no loc grade 2 (moderate) return if asymptomatic for 1 week loc <5 min pta >30 min confusion with amnesia no loc grade 3 (severe) may return after 1 month, if asymptomatic for 2 weeks loc >5 min pta >24 hours loc * loc = loss of consciousness ** pta = post-traumatic amnesia. sajsm vol 22 no. 4 2010 91 on-field the aim of immediate management is to stabilise the head-injured player. basic aspects of first aid involving cervical spine protection followed by airway, breathing and circulation evaluation and management take priority. the game should be stopped during this period. this applies especially to all cases where there has been loss of consciousness, the player is confused or has any suggestion of associated neck injury (neck pain, numbness or limb paraesthesiae). 8,9 in more subtle cases, a validated brief on-field neuropsychological test can be administered in the form of maddock’s questions, suitably modified for rugby, to assess recent memory. these questions have been shown to be sensitive in discriminating between concussed and non-concussed players (table iii). 31 the standard approach of asking orientation item questions (time, place and person) has been shown to be unreliable, as this component of cognitive function may be preserved in concussion. 31,32 the concussed player must be removed from the field of play or practice session immediately. 1,8,9 fieldside it should be emphasised that the concussed player must be assessed by a medical doctor as soon as possible following injury. the main aims of the fieldside assessment are to confirm the diagnosis of concussion, perform an initial (baseline) symptom analysis and to determine if there are urgent indications for referral to hospital (table iv). 9 best performed in a quiet medical room, this assessment involves a thorough history and neurological examination, noting any symptoms of concussion and excluding potential catastrophic signs of intracranial injury. the most practical tool for this assessment is the scat2 card. this is a combination of internationally utilised clinical concussion assessment tools summarised into a user-friendly format (fig. 1). 7 although not yet validated, the scat2 is a useful international norm and clinicians are encouraged to use the tool to promote consistency in clinical concussion assessment. following this, the team physician must decide if there is any indication to refer to hospital or whether the player may be adequately managed at home. home supervision requires a responsible adult to be present as well as a set of guidelines (table v). returning a concussed player to play on the same day is contraindicated. 7 hospital referral and brain imaging the results of standard brain imaging techniques are almost always normal in concussion. 1,7,8 if the player has been unconscious for any period of time, has deteriorating drowsiness, recurrent vomiting, unusual or aggressive behaviour or focal neurological signs, or if there is any other clinical suspicion of a possible intracranial lesion, it is recommended that the player be referred to a tertiary care hospital and either a computed tomographic (ct) or magnetic resonance image (mri) scan be performed. 7 if there are no indications for these investigations and the concussed player’s condition is improving over an initial 2-hour observation period he/she may be discharged home in the care of a responsible adult who is in possession of a head injury advice form (table iv). 1 follow-up consultation return-to-play decisions require serial medical evaluations and should not be made after the initial fieldside and/or emergency room table iii. maddocks questions 31 • which ground are we at? • which team are we playing today? • who is your opponent today? • which half is it? • how far into the half is it? • which side scored last? • which team did we play last week? • did we win last week? table iv. indications for urgent referral to hospital for special investigation and admission1 any player who has or develops the following: • fractured skull • penetrating skull trauma • deterioration in conscious state following injury • focal neurological signs • confusion or impairment of consciousness >30 minutes • loss of consciousness >5 minutes • persistent vomiting or increasing headache post injury • any convulsive movements • more than one episode of concussive injury in a match or training session • where there is assessment difficulty (e.g. an intoxicated patient) • all children with head injuries fig. 1. the scat2 card (first page). 7 92 sajsm vol 22 no. 4 2010 evaluations. this is one of the central tenets of modern concussion management protocol. 1,7-9 the evaluations should preferably be performed by a clinician (sports medicine physician, neurologist or neurosurgeon) with experience in concussion management and au fait with recommended guidelines. to facilitate this, sports concussion south africa has introduced the concept of the ‘sports concussion centre’, a multidisciplinary network of cross-referring medical professionals with skills in head injury management co-ordinated by the primary care sports medicine physician. the skills of neurologists, neurosurgeons, neuropsychologists, physiotherapists and exercise therapists/biokineticists may be employed for specific indications. the zurich guidelines state that trained neuropsychologists are in the best position to interpret neuropsychological (np) tests, but stress that this may not always be possible, in which case other medical professionals may both conduct and interpret such tests. the zurich document particularly emphasises that the return-to-play decision is a medical one. 7 co-ordination of an athlete’s management by a neuropsychologist alone or via internet or telephonic consultation is deemed clinically inappropriate and medicolegally treacherous. the aim of serial evaluations is to determine whether the player has fully recovered from concussion and is able to return to play. this is best performed by combining a clinical assessment with neuropsychological testing as an objective and scientifically valid means of assessing recovery. the clinical examination remains the most significant and universally accessible part of the assessment. the advantage of serial assessments is that comparison with previous visits becomes possible and a trend emerges of a player’s recovery. in order to obtain as much clinical information as possible the following parameters should be more thoroughly assessed at follow-up consultations: 1,7-11 • history of the specific head injury • history of previous concussions or associated injuries (neck, maxillofacial) • symptoms at the time of injury (in particular amnesia has been shown to be prognostically important) 26 • current symptoms • verbal and numeral competency • balance 8 • cardiovascular status – blood pressure, pulse (unpublished data: kohler and patricios) • neurological status • cranial nerves • motor function • sensory function • cerebellar function • associated injuries, especially involving the neck and maxillofacial structures. a well-formatted standard assessment protocol is best suited for this purpose. the scat2 assessment form is the most recent attempt at achieving uniform international clinical assessments. other templates include the acute concussion evaluation form devised by gioia and collins and used by the center for disease control. 33 neuropsychological testing post-concussion recovery rates vary between individuals. 34,35 some players may take days and others may take weeks to recover. individual factors associated with each concussion injury are different and emerging evidence has suggested that genetic factors may be involved in both the response to head injury and recovery rates. 1,9 there are dangers associated with universal mandatory exclusion criteria. it may be tempting to assume that a player has completely recovered from concussion as soon as an arbitrary time period has passed and that a medical assessment is not necessary, when in fact brain function, as measured by neuropsychological evaluation, is still abnormal. 35 a neuropsychological test is designed to assess the ability of the brain to process information (cognitive function). 34,35 traditional ‘paper and pencil’ tests, such as the digit symbol substitution test, have been replaced by more practically applied computerised neuropsychological tests. computer tests are quick and easy to administer, show fewer learning effects and, more importantly, are able to detect very subtle changes in cognitive function by table v. patient discharge information for 48 hours after injury a normal x-ray, ct or mri scan does not exclude concussion you may be referred home after being assessed. in this case: • always make sure that you are in the presence of a responsible adult for 48 hours. • record and monitor the symptoms of concussion including headache, nausea, dizziness, fatigue, sleep disturbances, memory lapses, mood swings, poor concentration or any other feeling that concerns you. • complete rest and sleep will help recovery. do not: • drive a motor vehicle or motor cycle if symptomatic • consume alcohol • take excessive amounts of painkillers (follow doctor’s orders) • place yourself in an environment of loud noise and excessive light • study • work at the computer • exercise until re-evaluation by a doctor contact your nearest emergency department immediately if: • any of the symptoms deteriorate • the headache becomes severe or does not respond to mild analgesics (e.g. panado) • you have a seizure (fit) • you experience excessive irritability • you experience visual disturbances • you experience balance problems • you or anyone else is concerned about your condition decisions regarding returning to sport will be made taking into consideration your individual circumstances including medical history, previous head injuries and current symptoms. you must receive clearance from a doctor before returning to sport. sajsm vol 22 no. 4 2010 93 measuring response variability, a feature not found with the ‘paper and pencil’ tests. computerised tests are cost effective and easily accessible to a large number of players. the tests are designed for medical doctors to administer, as the aim of the test is to determine whether cognitive dysfunction is present and not the reason for abnormal function. 35 examples of computerised tests include cogstate sport (previously cogsport), immediate post-concussion assessment and cognitive testing (impact), automated neuropsychological assessment metrics (anam) and headminders. in line with most major rugby-playing countries, doctors working for the south african rugby union (saru) have utilised cogstate sport, developed by leading concussion neuroscientists in australia and extensively peer-reviewed in the medical literature, as an objective measure of cognitive function following head injury. 34,35 this test is able to measure performance variability, a key measure in concussion diagnosis. the test can be administered by team physicians and performed as part of a pre-season evaluation forming a baseline neuropsychological assessment. of significant use in the application of neuropsychological testing is this pre-season (baseline) test. these pre-injury data ensure more reliable comparisons with postconcussion assessments 11,13 and will aid in the detection of subtle cognitive impairment, eliminate the need to compare with ‘normative data’ and assist with accurate clinical decision-making. the baseline data also ensure that test performance is not adversely affected by disease, drugs, practice effects and malingering. 34,35 a report detailing the player’s response speed, accuracy and consistency is generated. the test can be repeated following a head injury to determine whether cognitive function has deviated from baseline. the benefits are that the player returns to play cognitively as well as symptomatically recovered and has the ability to perform sports-specific skills optimally. newer protocols suggest not testing the athlete while symptomatic as this may induce unnecessary cognitive stress, possibly increase the chances of a practice effect and not alter the immediate management of the player. 7,8 issues of cost and accessibility may prevent the use of computerised tests and concussion management protocols should be able to be implemented without their use. biopsychosocial factors such as age, gender, education level, chemical dependency, co-existing medical and psychiatric conditions and level of alertness have also been suggested as having an influence on baseline scores, making it important that baseline scores are validated and comparative postinjury scores interpreted in a clinical context. a neuropsychologist, as part of the multidisciplinary sports concussion team, should be consulted especially if cognitive function is severe and prolonged, in cases of recurrent concussion over a short period, in players who appear to suffer concussion with relatively minor impacts, where neurological or psychological co-morbidity exists (e.g. depression, attention deficit disorder, migraine sufferers) and in cases where a decision to stop a player participating in contact or collision sport is to be considered. in these cases the neuropsychologist will perform a more extensive battery of verbal, pencil-and-paper and computerised tests to establish the cognitive implications of the injury. saru has consultant neuropsychologists as part of its head-injury management team and clinicians involved in assessing such athletes are encouraged to be able to ensure appropriate access to such professionals. realistically, scarcity of financial resources, lack of internet access and geographical remoteness may well make the ‘gold standard’ approach unattainable. in these cases, a systematic and thorough clinical evaluation and repeated monitoring with the scat 2 card will ensure that a player has recovered fully before returning to play. in particular, the following must have been achieved: • a symptom score of zero, i.e. asymptomatic • no aggravation of symptoms with exercise or cognitive stress • completed standardised assessment of concussion scores (sac) including full marks for the orientation score and acceptable and serially improving scores for the immediate and delayed memory score and the concentration score • a no-error score for balance • a no-error score for co-ordination. as declared on the scat form, normative data are not available. hence serial assessments assume a more significant role in identifying trends in improvement. in addition, the scat score should be interpreted in the context of a thorough general and neurological history and examination by a doctor. of specific interest are the following modifying factors which may mitigate against a quicker return to play or predispose to further concussive injury: 10 • mechanism of injury where seemingly less significant impacts may be responsible for repeated concussions • a record of whether amnesia (loss of memory) was present, whether retrograde or anterograde, and for how long • a previous history of concussion, especially of recent and recurrent injuries (3 or more) • previous or current neurological conditions (meningitis, encephalitis, epilepsy) • psychological conditions (depression, anxiety, sleep disorders) • learning disabilities (attention deficit hyperactivity disorder) and treatment with psychostimulants (methylphenidate) • other medical conditions (e.g. hypothyroidism), or medication (e.g. ssris) that may impact on the nervous system. return-to-play protocol the final phase of a safe, structured and supervised concussion rehabilitation protocol involves the progressive exposure of the recovering athlete to increasing degrees of exercise intensity while monitoring symptoms. 1,8,9,11 this process should be preceded by both clinical and cognitive recovery. in other words, the player should be asymptomatic, have a normal neurological examination and neuropsychological data (where utilised) that have returned to baseline or are comparable with age-appropriate norms. the end point is a return to match competition. exercise stress testing follows a stepwise process with stage-associated objectives: 1,7-11 • light aerobic exercise (walking and stationary cycling) – increase heart rate • sport-specific training (running drills, ball handling skills) – add movement • non-contact drills – exercise, coordination, cognitive load • full-contact practice – confidence, functional skills • game play. the player can proceed in a stepwise progression to the following level after 24 hours provided he/she is asymptomatic. 1 if any postconcussion symptoms develop, the player should drop back to the previous asymptomatic level. in players with modifying factors such as a history of recurrent concussions, neurological or psychological co-morbidity or who appear to be more easily concussed, it may be prudent to extend the return-to-contact play process by making each stage longer than 24 hours. 94 sajsm vol 22 no. 4 2010 pharmacological intervention one of the frustrations of treating mild traumatic head injuries is the lack of direct positive influence that the clinician has on the outcome. although much can be done that may aggravate the condition, such as exposing the patient to physical and cognitive stress, there is as yet no evidencebased pharmacological treatment that the physician can administer to the concussed patient that will influence the course of the condition. hence the physician’s role has been described as promoting ‘masterly inactivity’. 19 pharmaceutical agents with potential for influencing the neurometabolic cascade postulated as being central to the pathophysiology include corticosteroids, calcium channel blockers, antioxidants, glutamate receptor antagonists, hyperbaric oxygen therapy and hypothermia. the other area of intervention involves the treatment of postconcussive symptoms. acute headache may be treated with mild analgesics that do not influence the potential for bleeding (e.g. paracetamol), nausea with anti-emetics (e.g. cyclizine) and prolonged dizziness with anti-vertigo agents (e.g. cinnarizine). treatment of neck muscle spasm by a physiotherapist is an appropriate nonpharmacological intervention that may lessen headaches. more persistent symptoms such as insomnia may be treated with hypnotics, affective disorders with ssris and cognitive or attention deficit with neurostimulants such as methylphenidate. again, these treatments are intuitive and empirical and there is no evidence for them influencing the pathophysiology of concussion. consultation with and monitoring by a broader team of appropriate specialists including neurologists, neurosurgeons and psychologists is advised. education and research each of the important consensus documents has emphasised the need for education of the sporting public (players, parents, coaches, referees and administrators) as well as the medical fraternity as to the nature of concussive injury and best management principles. 1,7-11 lectures to these groups, accessible information (brochures, posters and websites) and print/electronic media coverage, serve to expose those involved in contact and collision sport to the protocols available. conclusion sports-related concussion management appears to have partially emerged from the somewhat nebulous and eclectic guidelines of the 20th century. the series of international consensus statements since 2001 appear to not only have consolidated expert opinion into a more unitary model, but exponentially spurred research and interest in the field. many questions remain unanswered, particularly concerning the pathophysiology of mild traumatic brain injury and possible pharmacological interventions. this review of current concepts in concussion management highlights the need for ongoing education of lay and medical target groups, a support network within the sporting code, a structured clinical protocol incorporating a thorough history, serial clinical assessments and a graded return to play process. where available, computerised neuropsychological testing is a useful adjunct and often the only objective representation of changes to the affected player’s brain. adopting international conventions in the management of south african rugby players at all levels is in the best clinical interest of our players, will allow for a framework of practical research and help mitigate against the possible medicolegal consequences of poorly managed head injuries. references (this list of references has been restricted by space; a full list may be viewed at www.boksmart.com or obtained from the author) 1. aubry m, cantu r, dvorak j, et al. summary and agreement statement of the first international conference on concussion in sport, vienna 2001. recommendations for the improvement of safety and health of athletes who may suffer concussive injuries. br j sports med 2002;36:6-10. 2. kemp, spt, hudson, z, brooks, jh, fuller, cw. clin j sport med 2008;18:227-234. 3. nathan m, goedeke r, noakes t. the incidence and nature of rugby injuries experienced at one school during the 1982 rugby season. s afr j sports med 1983;64:132-137. 4. gerberich sg, priest jd, boen jr, straub cp, maxwell re. concussion incidences and severity in secondary school varsity football players. am j public health 1983;73:1370-1375. 5. petterson j, skelton r. glucose enhances long-term declarative memory in mildly head-injured varsity rugby players. psychobiology 2000;28:81-89. 6. holtzhausen l, schwellnus m, jakoet i, pretorius a. pre-season assessment of south african players in the 1999 rugby super 12 competition. s afr j sports med 2002;9:15-21. 7. mccrory p, johnston k, meeuwisse w, et al. summary and agreement statement of the 2nd international conference on concussion in sport, prague 2004. br j sports med 2005; 39; 196-204. 8. guskiewicz km, bruce sl, cantu rc, et al. national athletic trainers position statement on the management of sports-related concussion. j ath tr 2004;39;278-295. 9. herring sa, bergfield ja, boland a, et al. putukian acsm team physician consensus statement: concussion (mild traumatic brain injury) and the team physician. m med sc sport ex 2006;2;395-399. 10. mccrory p, meeuwisse w, johnston k, et al. consensus statement on concussion in sport—the 3rd international conference on concussion in sport held in zurich, november 2008. br j sports med 2009;43:i76-i84. 11. patricios js. the masters’ voices to mandela’s melody: a south african template for complete concussion care. br j sports med 2009;43:i91-i105. 12. giza gc, houda da. the neurometabolic cascade of concussion. j athl train 2001;31(3);228-235. 13. mccrory p, collie a, anderson v, davis g. can we manage sport-related concussion in children the same as in adults? br j sports med 2004;38;516-519. 14. noakes t, du plessis m. common rugby injuries, including anatomical sites and mechanisms of injury. rugby without risk. cape town: jl van schaik, 1996;45-86. 15. bruce d. delayed deterioration of consciousness after trivial head injury in childhood. br med j 1984;289:715-716. 16. cantu rc. second-impact syndrome. clin sports med 1998;17:37-44. 17. cantu rc. posttraumatic retrograde and anterograde amnesia: pathophysiology and implications in grading and safe return to play. j athl train 2001; 36:244-248. 18. mccrory pr, bladin pf, berkovic sf. retrospective study of concussive convulsions in elite australian rules and rugby league footballers: phenomenology, aetiology, and outcome. bmj 1997;314:171-174. 19. mccrory p. should we treat concussion pharmacologically? br j sports med 2002;36:3-5. 20. gronwall d, wrightson p. delayed recovery of intellectual function after minor head injury. lancet 1974;2:605-609. 21. jordan bd. apolipoprotein ee4 and fatal cerebral amyloid angiopathy associated with dementia pugilistica. ann neurol 1997;38:698-699. 22. jordan bd. sparring and cognitive function in professional boxers. phys sportsmed 1996;24:87-98. 23. matser ej, kessels ag, lezak md, jordan bd, troost j. neuropsychological impairment in amateur soccer players. jama 1999; 282:971-973. 24. jordan bd. genetic susceptibility to brain injury in sports: a role for genetic testing in athletes? phys sportsmed 1998;26:25-26. 25. collins mw, lovell mr, iverson gl, cantu r, maroon j, field m. cumulative effects of concussion in high school athletes. neurosurgery 2002;51:1175-1181. 26. cantu rc. guidelines for return to contact sports after cerebral concussion. phys sportsmed 1986;14:75-83. 27. colorado medical society sports medicine committee. guidelines for the medical management of concussion in sports. colorado medical society, denver 1991. 28. gronwall dm. paced auditory serial-addition task: a measure of recovery from concussion. percept mot skills 1977;44:367-373. 29. mcintosh as, mccrory p, finch cf, best jp, chalmers, dj, wolfe, r. does padded headgear reduce head injury in rugby union football? med sci sports exerc 2009;41(2);306-313. 30. singh, gd, maher, gj, padilla, rr. customised mandibular orthotics in the prevention of concussion/mild traumatic brain injury in footballers: a preliminary study. dental traumatology 2009;25:515-521. 31. maddocks dl, dicker gd, saling mm. the assessment of orientation following concussion in athletes. clin j sport med 1995;5:32-35. 32. mccrea m, kelly jp, randolph c, et al. standardized assessment of concussion (sac): on-site mental status evaluation of the athlete. j head trauma rehabil 1998;13:27-35. 33. gioia g, collins m. acute concussion evaluation (ace). heads up: brain injury in sport your practice tool kit. center for disease control, www. cdc.gov/ncipc/pub-res/tbi_toolkit/tbi/ace, modified june 2007. 34. darby d, maruff p, collie a. detection of mild cognitive impairment with multiple baseline assessments in one day. neurology 2002;59:1042-1046. 35. collie a, maruff p. computerised neuropsychological testing. br j sports med 2003;37:2-32. introduction in any medical consultation, the history serves as a very important initial assessment of the patient’s presenting complaint or condition. pre-participation evaluations (ppes) are largely designed for medically qualified personnel to screen for players who may be at risk of illness or injury. 1-12 the most recent example of such a template is fifa’s pre competition medical assessment (pcma) 13 used to screen all participants before the recent fifa 2010 world cup. much of the emphasis is on cardiovascular disease, as this is the largest cause of sudden death in young athletes. 14 in south african rugby, particularly at school and community club level, pre-participation screening is rarely conducted owing to a lack of resources and skills. in designing a pre-participation screen for coaches, the challenge is to be able to ‘red flag’ potentially serious cardiovascular risk factors as well as musculoskeletal and neurological risks pertinent to a collision sport such as rugby, using easily understood questions that cast the screening net wide enough to determine who should be formally medically assessed (see table i). 15 cardiovascular screening most athletes are healthy. only 3 13% require further evaluation, and the disqualification rate for 10 million annual examinations is less than 1%. 10 the overall rate of sudden death in male athletes younger than 35 years is quite low, approximately 0.75 per 100 000 participants per year. 14 congenital cardiac anomalies account for most sudden deaths in these patients. the most common anomalies are hypertrophic cardiomyopathy and coronary artery anomalies. 14,16 the most common coronary abnormality is a left main coronary artery originating off the right sinus. myocarditis, rupture of the aorta, arrhythmogenic right ventricular dysplasias, idiopathic left ventricular hypertrophy, aortic stenosis and premature coronary artery disease account for most of the remaining fatalities. 2 cardiovascular screening is regarded as the most important part of a ppe because of the potential for sudden death in athletes with undiagnosed heart disease. 17,18 personal and family histories of cardiovascular illness have been shown to be more sensitive screens than a physical examination, revealing 64 78% of conditions that could prohibit or alter sports participation. 5,12 nevertheless, screening on the basis of symptoms is certainly not comprehensive and hypertrophic cardiomyopathy, the most common cause of death among 12 32-year-old athletes on the field, may not produce symptoms before sudden death. 19 hypertrophic cardiomyopathy is a heterogeneous group of disorders acquired through autosomaldominant transmission with incomplete penetrance, and signs and symptoms may not become manifest until early adulthood. 20 detecting persons with marfan syndrome before they participate in sports is important because the defective aortic media can rupture during basketball, volleyball and, presumably, other sports activities. 21 where a layperson such as a coach is performing the screen and has limited experience in screening for potential risks such as marfan syndrome and does not have the benefit of a physical examination review boksmart: pre-participation screening of rugby players by coaches based on internationally accepted medical standards abstracts a comprehensive medical history forms a significant part of any medical assessment or screening. in the athlete, pre-participation screening is aimed at determining those aspects of personal and family history that place the participant at greater risk of sudden death, serious illness or musculoskeletal injury. in rugby union, where the incidence of head and neck injuries is higher than in other sports, emphasis needs to be placed on screening for potential risk factors for neurological injury. in a south african rugby environment, pre-season medical screening is not standard and indeed rarely practised. in most club and school settings, the rugby coach may well be the person most in contact with players and therefore in the best position to conduct an initial screening. this article reviews the relevant literature pertinent to such a guideline. correspondence: dr jon patricios morningside sports medicine po box 1267 parklands 2121 tel: +27 11 8839000 fax: +27 11 442 8233 e-mail: jpat@mweb.co.za j s patricios (mb bch, mmedsci (sheffield), facsm, ffsem (uk))1 r m collins (mb bch, msc (sports med))2 1 sports physician, johannesburg, extraordinary lecturer, department of sports medicine, university of pretoria, and consultant, south african rugby’s boksmart injury prevention programme 2 sports physician in private practice, johannesburg, team physician, lions rugby union, and lecturer, department of sports medicine, university of pretoria 62 sajsm vol 22 no. 3 2010 sajsm vol 22 no. 3 2010 63 or ancillary studies (e.g. ecgs, echocardiogram) to supplement the history, the risks may be greater. neurological screening head and neck injuries account for the largest proportion of catastrophic injuries in south african rugby 22 and should therefore be adequately screened for in any ppe. neck injuries a report of burning pain, weakness, numbness or tingling in all four or only the upper extremities raises concern of cervical spine impingement. possible aetiologies for this condition would include atlantoaxial instability, congenital fusions and disk herniations. 14 nerve injuries ‘burners’ or ‘stingers’ are usually secondary to a brachial plexus stretch or cervical root irritation. the athlete should be free of any neck or radicular pain, and have full range of motion and strength in all movements of the cervical spine before returning to sports participation. 23 recurrent episodes require referral for cervical radiographic and/or neurophysiological studies before clearance. concussion pre-participation examinations for neurological problems such as concussion are extremely difficult, as most concussions recover fully and leave no residual indicators. in addition, concussions sustained in contact and collision sports may simply reflect an athlete’s level of exposure to the sport rather than an underlying intrinsic risk factor. 3 the definition of concussion has been broadened to include any trauma-induced alteration in mental state (table ii) and does not necessarily include loss of consciousness or amnesia as in previous definitions. 23-26 the range of symptoms possibly associated with concussion should be made clear to athletes, many of whom may not have recognised or appreciated their significance. risks of playing while the athlete has prolonged concussion include exacerbation or prolongation of symptoms of the postconcussion syndrome. this is of particular significance in young players exposed to a learning environment. the second-impact syndrome is a less common but far more catastrophic consequence of unrecognised or poorly managed concussion. a second blow (even a relatively mild impact) to a brain that has not yet recovered from a previous blow may result in loss of autoregulation. 27,28 any player who is still symptomatic from a concussive blow should not be exercising and definitely not participating in contact or collision sports. 24,26,29 finally, there is evidence of the cumulative effect of concussions, particularly where these injuries may not have been recognised or managed appropriately. 30 coaches detecting any symptoms, recent history of concussion or multiple concussions in a player should ensure that the player seeks appropriate medical advice. to help to mitigate the difficulties in detecting concussion risk in collision sport, it is recommended that an additional and more extensive baseline screening of symptoms, previous episodes and comorbid neurological and psychological risk factors be conducted. 8 in addition, the emergence of computerised neuropsychological testing, where accessible, provides the player with an assessment that may give insight into cognitive compromise related to previous injuries and serve as a baseline measure against which the consequences of further concussions may be measured. 24,26,29 convulsive disorders guidelines from the american academy of pediatrics 31 clear young athletes with well-controlled convulsive disorders for participation in conventional school-sponsored sports. however, in a sport entailing higher risk, including rugby union, neurological consultation should be considered. athletes with poorly controlled seizures should be withheld from contact or collision sports. 14 musculoskeletal injuries most studies have shown that musculoskeletal findings are the major category of abnormalities leading to restriction from sports activities. 11 the most common musculoskeletal injury to restrict an athlete from activity is a knee injury, followed by an ankle injury. 4 in musculoskeletal injuries, the chance of re-injury is high without proper rehabilitation. 16 specific examples include patella and shoulder dislocations. 11 however, this category of injury is unlikely to be catastrophic and, therefore, in the interests of efficiency, should receive no more than a mention in a coach’s ppe. other medical conditions leading causes of non-traumatic, non-cardiac sports death are exertional hyperthermia, followed by exertional rhabdomyolysis and status asthmaticus. 32 current infections conditions such as influenza or gastroenteritis affecting the player at the time of questioning should preclude him or her from training and appropriate medical care should be sought to avoid the risk of myocarditis and pericarditis. 9,10,14 exercise-induced asthma status asthmaticus is one of the non-traumatic causes of death in high-school and college athletes. however, the incidence in survey populations is only four deaths in 30 million athletes. 32 evidence of exercise-induced asthma is sought in the pre-participation examination so that medical prophylaxis (typically with a beta agonist) can be implemented, not to disqualify the athlete. heat-related illness physicians can screen for a tendency toward exertional hyperthermia by asking about a previous history of heat-related illness. athtable i. cardiovascular screening history for preparticipation examinations critical questions 14 exertional chest pain or discomfort, or shortness of breath? exertional syncope or near-syncope, or unexpected fatigue? past detection of cardiac murmur or systemic hypertension? known family history of hypertrophic cardiomyopathy, other cardiomyopathies, long qt syndrome, marfan syndrome, significant dysrhythmias? family history of premature death or known disabling cardiovascular disease in a firstor second-order relative younger than 50 years? (more concern if younger than 40 years) letes with this condition are usually allowed to participate in sports, but temperature extremes must be avoided and appropriate means of cooling such as breaks in play and iced towel-downs should be followed. 11 sickle cell trait the american academy of pediatrics and the national collegiate athletic association recommend that persons with sickle cell trait be allowed to participate in sports without any restrictions. 31 there is evidence that persons with sickle cell trait have increased susceptibility to exertional rhabdomyolysis, with the potential for renal failure and death. patients with sickle cell trait should be counselled about appropriate hydration and acclimatisation to reduce risks. rugby players should note that high exertion and contact or collision sports are generally contraindicated in patients with sickle cell disease, even if appropriate hydration can be ensured. solitary organs whether athletes with one paired organ, especially one kidney, should participate in sport, particularly collision sports, is a topic of controversy. all such patients need to understand the risks so they can make an informed decision. no contact or collision sports are allowed if a single kidney is polycystic or abnormally located. 1 when an athlete has only one functional eye (with less than 20/40 corrected visual acuity), further evaluation by an ophthalmologist is recommended. 33 these athletes can participate only in sports that permit the use of protective eyewear (such as swimming, track and field, and gymnastics) and do not involve projected objects. wrestling, boxing and martial arts are contraindicated sports and, by inference, rugby must also be regarded as risk sport for these individuals. the only modification for an athlete with one testicle is the use of a protective cup or ‘box’ during contact sports. the chance of injury and the subsequent possibility of loss of fertility should be mentioned in counselling. 1 other benefits of screening enquiries about medication use may have several benefits. firstly, medications may have a direct influence on performance, e.g. antihistamines may cause drowsiness. secondly, medications may require therapeutic use exemption clearance or be banned in competition. this should be brought to the player’s attention. thirdly, it may serve as a means of determining a medical condition that the athlete did not feel was worth mentioning because it is such an inherent part of his/her life, e.g. asthma, diabetes or hypertension. finally, the athlete may mention additional supplements (legal and illegal) that are being consumed. 14,34 a further benefit of ppe is the opportunity it affords the coach to gain some insight into a player on a one-to-one basis. although not specifically targeted in most ppe questionnaires, issues not directly related to sport but affecting the athlete’s lifestyle such as smoking, alcohol and drug use may emerge during the questioning, affording counselling (formal or informal) to be given in these areas. 1 ethical considerations the coach, as a lay person, should not necessarily be privy to medical information that the player may regard as confidential. hence, an option should be included in the survey that allows the player to share this information with a medical practitioner in private, particularly if this information, e.g. hiv infection, has implications for the player and others’ participation in exercise. fitness assessment although the coach does not have the advantage of a physical examination to complement the history, he/she is afforded the benefit of seeing the athlete under conditions of physical stress when training. this can be utilised as a screening tool in itself and a sort of field ‘stress test’. in particular, players who fail to cope with exercise that their peers find reasonable, those who show a marked decrease from previous levels of performance, those who describe symptoms during or following exercise or those who appear hindered by injury should be referred for medical evaluation. 9,11,14 conclusion in an amateur sporting environment where pre-participation screening is sparingly utilised, the use of a screening tool administered by rugby coaches could significantly and positively impact on the detection and reduction of potentially catastrophic illness and injury. a review of the relevant literature shows the player’s medical and family history to be the most important part of the screen and is therefore within the parameters of such a questionnaire. in particular this would aim at detecting a higher risk for cardiac-related sudden death, concussion and other neurological injuries. acknowledgements this paper was commissioned by the boksmart programme – a national programme sponsored by absa and implemented on behalf of the south african rugby union and the chris burger/petro jackson players’ fund. the goal of the programme is to teach safe and effective techniques, which will reduce the incidence and severity of injury, make the game safer for all involved and improve rugby performance. references 1. abdulla a. the pre-participation of athletes. middle eastern journal of family medicine 2007;5(4):17-20. 2. american heart association. cardiovascular preparticipation screening of competitive athletes. med sci sports exerc 1996;28:1445-1452. table ii. symptoms and signs of concussion28 physical cognitive emotional sleep headache poor depression drowsiness photophobia concentration irritability insomnia dizziness problems mood swings sleeping more phonophobia remembering aggressiveness difficulty getting to sleep nausea feeling numbness/ ‘foggy’ tingling feeling vomiting ‘slowed down’ fatigue visual changes balance problems 64 sajsm vol 22 no. 3 2010 sajsm vol 22 no. 3 2010 65 3. fuller c, ojelade e. preparticipation medical evaluation in professional sport in the uk: theory or practice? br j sports med 2007;41:890-896. 4. grafe mw, paul gr, foster te. the preparticipation sports examination for high school and college athletes. clin sports med 1997;16:569-591. 5. krowchuk dp. the preparticipation athletic examination: a closer look. pediatr ann 1997;26:37-49. 6. maron bj, isner jm, mckenna wj. 26th bethesda conference: recommendations for determining eligibility for competition in athletes with cardiovascular abnormalities. med sci sports exerc 1994;26:s261-267. 7. maron bj, thompson pd, puffer jc, et al. cardiovascular preparticipation screening of competitive athletes. circulation 1996;94:850-856. 8. mccrory p. preparticipation assessment for head injury. clin j sport med 2004;14:139-144. 9. morphet jam. screening for sudden cardiac death in adolescent athletes. perspect cardiol 2001;17(8):37-47. 10. smith dm. preparticipation physical evaluation. 2nd ed. minneapolis: physician and sports medicine, 1997:1-46. 11. smith j, laskowski er. the preparticipation physical examination. mayo clin proc 1998;73:419-429. 12. wappes jr (executive editor). preparticipation physical evaluation. 3rd ed. minneapolis: mcgraw hill, 2005. 13. fifa pcma form. available at: http://www.fifa.com/mm/document/ afdeveloping/medical/01/07/26/86/fifapcmaform.pdf (accessed: 17 july 2010). 14. kurowski k, chandran s. the preparticipation athletic evaluation. am fam physician 2000;61:2683-2690, 2696-2698. 15. holtzhausen l, schwellnus m, jakoet i, pretorius a. pre-season assessment of south african players in the 1999 rugby super 12 competition. s afr j sports med 2002;9:15-21. 16. abbott hg, kress jb. preconditioning in the prevention of knee injuries. arch phys med rehabil 1969;50:326-333. 17. basilico fc. cardiovascular disease in athletes. am j sports med 1999;27:108-121. 18. maron bj. hypertrophic cardiomyopathy. lancet 1997;350:127-133. 19. maron bj, casey sa, poliac lc, gohman te, almquist ak, aeppli dm. clinical course of hypertrophic cardiomyopathy in a regional united states cohort. jama 1999;281:650-655. 20. lerakis s, sheahan rg, stouffer ga. hypertrophic cardiomyopathy. am j med sci 1997;314:324-329. 21. gott vl, pyeritz re, magovern gj, cameron de, mckusick va. surgical treatment of aneurysms of the ascending aorta in the marfan syndrome. n engl j med 1986;314:1070-1074. 22. noakes t, du plessis m. common rugby injuries, including anatomical sites and mechanisms of injury. in: rugby without risk. pretoria: jl van schaik, 1996:45-86. 23. cantu rc, bailes je, wilberger je. guidelines for return to contact or collision sport after a cervical spine injury. clin sports med 1998;17:137146. 24. aubry m, cantu r, dvorak j, et al. summary and agreement statement of the first international conference on concussion in sport, vienna 2001. recommendations for the improvement of safety and health of athletes who may suffer concussive injuries. br j sports med 2002;36:6-10. 25. cantu rc. cerebral concussion in sport. management and prevention. sports med 1992;14:64-74. 26. herring sa, bergfield ja, boland a, et al. acsm team physician consensus statement: concussion (mild tarumatic brain injury) and the team physician. med sci sport exerc 2006;2:395-399. 27. cantu rc. second-impact syndrome. clin sports med 1998;17:37-44. 28. gioia g, collins m. acute concussion evaluation (ace). heads up: brain injury in sport. your practice tool kit. center for disease control. www. cdc.gov/ncipc/pub-res/tbi_toolkit/tbi/ace (modified june 2007). 29. guskiewicz km, bruce sl, cantu rc, et al. national athletic trainers position statement on the management of sports-related concussion. journal of athletic training 2004;39:278-295. 30. collins mw, lovell mr, iverson gl, cantu r, maroon j, field m. cumulative effects of concussion in high school athletes. neurosurgery 2002;51:1175-1181. 31. american academy of pediatrics committee on sports medicine. recommendations for participation in competitive sports. pediatrics 1988;81:737-739. 32. van camp sp, bloor cm, mueller fo, cantu rc, olson hg. non-traumatic sports death in high school and college athletes. med sci sports exerc 1995;27:641-647. 33. stock jg, cornell fm. prevention of sports-related eye injury. am fam physician 1991;44:515-520. 34. welder aa, melchert rb. cardiotoxic effects of cocaine and anabolic-androgenic steroids in the athlete. j pharmacol toxicol methods 1993;29:61-68. commentary 134 sajsm vol 23 no. 4 2011 introduction in response to randolph’s recent article published in current sports medicine reports (csmr), in which he argues against the utility of computerised neurocognitive baseline testing in the sports concussion context, 1 the present author submitted some critical commentary regarding the underpinnings of his argument, including material to suggest that his stance is counter-productive in terms of optimal healthcare and unwarranted. 2 in turn, randolph and mcgrew have presented a number of challenging responses, 3,4 including the statement that ‘to advocate for the addition of baseline neuropsychological testing for athletes at this time is scientifically unfounded, financially irresponsible and should be roundly condemned for confusing and raising false expectations in the athletes that are subjected to it as well as adding additional burden to an already overtaxed medical system’. 4 however, considerable concern remains about what appears to be biased and uncritical dismissal of the use of neurocognitive screening in this forum generally by these authors (randolph and mcgrew), and an unwarranted demeaning of the impact test in particular. 1 in this regard, the present author’s previous commentary 2 drew attention to the limitations of evidence that is derived exclusively from group research to facilitate optimal health service, rather than incorporating other crucial factors such as theoretical pointers and clinical case observations given the multitude of genetic, biologic and co-morbid variations as has been eloquently argued elsewhere. 5-7 further, the author’s prior commentary 2 draws attention to randolph’s surprising criticism of the impact test because it produces a multifunction test report rather than yielding a single indicator of brain dysfunction, whereas this can be considered to be one of its most significant strengths. a ‘single entity’ assessment approach has long been thoroughly discredited in modern clinical neuropsychology. 8,9 finally, in terms of the various contributions to the debate in question, kutcher, 10 in more balanced fashion, warns that randolph’s target in his most recent article is ‘conspicuously narrow’, and that the practitioner is advised to take cognizance of the complexity of the issue, being ‘as leery of fool’s gold as dirty bathwater’. 10 accordingly, the purpose of the present commentary is to expand on the intricacies involved in this issue, with particular reference to randolph’s most recent article published in the csmr. 1 the argument to be presented accords with sentiments expressed in a rebuttal to randolph’s earlier article in the jat, 11 in which it was stated that ‘the article does not present a balanced and representative review of the literature … and does nothing to move our understanding of concussion forward … in addition, the authors’ opinions are inconsistent with current thought within the field of neuropsychology’. 12 statistical misrepresentation in light of clinical applications extracted from a study of broglio et al., 13 data are presented by randolph to bolster an argument about the poor test-retest reliability and relative sensitivity of the impact test. 1,3 much is made of a 40% false positive rate of impairment relative to baseline that occurred on at least one of the four impact test composites as reported in that study. 1,3 using the analogy of a thermometer, it is suggested that one would not wish to use such an instrument if it were so unreliable as to ‘classify 40% of healthy individuals as pyretic and 40% of pyretic individuals as healthy’. 3 however, there are a number of serious difficulties inherent in these extrapolations, as follows. firstly, in the broglio et al. study, three different computerised neurocognitive tests were administered to testees at baseline, day 45 and day 50. however, in the regular clinical situation, it is only a single neurocognitive test that is administered at baseline, and likewise on each follow-up test occasion. therefore, uncritical extrapolation of research outcome from the broglio study to document clinically applicable test-retest reliability, false positive indications of impairment, etc., in respect of any of these three programmes in isolation, has seriously compromised validity on methodological grounds, due to the confounding effect on each other of the multiple test administrations. further, from a neuropsychological perspective, to draw an analogous comparison between the single score measurement of a thermometer and a psychometric instrument is inappropriate. psychometric test scores do not have stand-alone positivistic meaning in their own right (as with a temperature thermometer), rather being a relativistic type of measurement requiring highly contextualised interpretation in the hands of those who have been trained in their use. 14 a single change score in isolation on a test such as impact, that incorporates at least four core composite scores in the clinical profile, 15 would be viewed sceptically in terms of its implications, and interpreted closely in relation to: the site of the injury; the symptom reports; the educational/ occupational abstract the purpose of this article was to contribute to an argument regarding the utility of computerised baseline and follow-up neurocognitive testing within the sports concussion arena. heated debate around this issue via a number of contributions has appeared recently in the journal current sports medicine reports, with its use being roundly condemned by one party as ‘scientifically unfounded’ and therefore ‘financially irresponsible’. it is proposed that this vehemently negative viewpoint is located in a ‘smoke and mirrors’ portrayal of the validity of such neurocognitive screening, being substantiated on questionable extrapolations from laboratory-type group research to the clinical situation. the stance runs counter to the tenets of modern clinical neuropsychology, and is incompatible with more rigorous scientific pointers from current research. abreast of the latest concussion in sport consensus recommendations, it is concluded that there is compelling support for the burgeoning use of computerised neurocognitive evaluation in the sports concussion arena as the optimal and most responsible healthcare currently available in this arena. ann b shuttleworth-edwards, phd professor of psychology, director national sports concussion initiative (nsci), department of psychology, rhodes university, grahamstown, south africa correspondence to: professor ann edwards (a.edwards@ru.ac.za) debating the utility of computerised neurocognitive testing in the sports concussion arena sajsm vol 23 no. 4 2011 135 background and special abilities and disabilities of the athlete; and, importantly, norms that are applicable to the testee in terms of the demographic influences of age, education and cultural affiliation. 16 essentially, the point that is being made here is that false positive indications derived from any scores, and particularly a single score, in the de-contextualised group research context such as pertains to the study of broglio et al., have minimal relevance in the appropriately conducted clinical neuropsychological examination. accordingly, randolph’s 40% false positive challenge regarding the use of the impact test is entirely without substance on clinical interpretive grounds, as well as on the most fundamental of methodological grounds. in contrast to these dubious implications derived from the study of broglio et al. are indications from many more rigorous studies, and some recent studies in particular, that serve to demonstrate an entirely opposite picture in terms of the discriminatory ability of the impact programme. 17,18 in these studies a high level of predictive value on the length of recovery is established for the impact programme of 73% taking both the cognitive tests and symptom reports into account, with an increase of 24% in sensitivity over the use of the symptom reports alone. 17 early postconcussion neurocognitive assessment on impact in an emergency department detected neurocognitive deficits that clinical grading could not, and correlated with the severity of deficit at 3and 10-day post-injury follow-up. 18 benefits of neuropsychological evaluation and concluding comments research outcome aside, there are non-debatable clinical advantages in having neuropsychological post-concussion evaluations available in the hands of the trained neuropsychologist. such benefit includes the ability to demonstrate the extent of cognitive malfunction during the recovery process in order to provide guidelines for scholastic or occupational purposes. even fairly brief periods of unrecognised and/ or unsubstantiated cognitive dysfunction in the wake of a concussion may have quite serious negative consequences within such settings, and calls for highly individualised recommendations supported by objective criteria. these goals are massively facilitated by the availability of follow-up computerised test data per se, and especially in comparison with baseline data. in sum, taking all the above into consideration, in direct opposition to the expressed sentiments of randolph and mcgrew, the impact test appears to be exactly the kind of tool that the present author would like to add to an investigative armamentarium with a view to enhancing medical management in respect of the sports concussive injury. it has clearly been endorsed by hundreds of clinicians worldwide in the burgeoning use of this particular tool. however, as cautioned by kutcher, 10 whether using impact or some other instrument of this type such as anam, cogstate sport or headminder, this procedure should not be followed blindly as part of a marketing ploy. nor should the process be seen as a shortcut to ruling brain dysfunction in or out. 14,19 rather it should take place via discretionary clinical evaluation of the optimal mechanism to employ in order to meet the health needs within the particular sports concussion arena, by a team of suitably qualified medical and neuropsychology practitioners. as such, the practice is fully in accordance with the recommendations of the most recent consensus on concussion in sport. 20 used appropriately within the confines of legitimate practice in clinical neuropsychology, the incorporation of computerised neurocognitive screening can be considered to have positively revolutionised the management of the sports concussive injury in the direction of becoming massively more refined than it was previously, thereby allowing for more optimal and responsible recovery and rehabilitative healthcare. a note on the impact programme the impact programme was developed within a research context approximately ten years ago, 15 and is currently in its 4th updated webbased and technologically sophisticated version. it consists of a userfriendly series of tests and a symptom check list that take about 25 minutes to complete, and produces an automated report that collates the neurocognitive and symptom outcome, for multiple test-taking occasions. there is a spectrum of functional modalities assessed based on traditional well-researched neuropsychological stimuli, including visual and verbal memory (immediate and delayed), visual motor speed, reaction time, as well as a cognitive efficiency index, and a test of impulse control that provides an indicator of test-taking validity. restricted web-based access to the report by designated clinicians enables high level neuropsychological interpretation of the outcome and feedback within a matter of hours, regardless of location of the testee. the test is acknowledged as the most widely used of all computer programmes that have been especially devised for use in the sports concussion arena. 1 acknowledgements acknowledgements for funding of the author’s concussion research programme are due to the national research foundation (nrf) and the joint research council of rhodes university, grahamstown, south africa. declaration of conflict of interests the author has been involved in concussion management in south africa and the uk for the past ten years, using the impact programme for clinical and research purposes. references 1. randolph c. baseline neuropsychological testing in managing sport-related concussion: does it modify risk? curr sports med rep. 2011;10(1):21-26. 2. shuttleworth-edwards a. response to the article on baseline testing: throwing away clinical gold with the statistical bathwater. curr sports med rep 2011;10(6):391-392. 3. randolph c. letter to editor-in-chief. curr sports med rep. 2011;10(6):393. 4. mcgrew ca. letter to editor-in-chief. curr sports med rep. 2011; 10(6):394. 5. miller dw, miller cg. on evidence medical and legal. j am phys surg 2005;10(3):7075. 6. upshur eg. looking for rules in a world of exceptions. reflections on evidencebased practice. perspect biol med 2005;48:477-489. 7. dattilio f, edwards d, fishman d. case studies within a mixed methods paradigm: toward a resolution of the alienation between researcher and practitioner in psychotherapy research. psychotherapy, theory, research, practice, training 2010;47(4):427-441. 8. walsh k. understanding brain damage: a primer of neuropsychological evaluation. 2nd ed. melbourne: churchill livingstone, 1991. 9. lezak md, howieson db, loring dw. neuropsychological assessment. 4th ed. oxford: oxford university press, 2004. 10. kutcher, js. letter to editor-in-chief. curr sports med rep. 2011; 10(6): 395. 11. randolph c, mccrea m, barr wb. is neuropsychological testing useful in the management of sport-related concussion? j athl train 2005;40(3):139-154. 12. lovell mr. letter to editor. j athl train 2006;41:137. 13. broglio sp, macciocchi sn, ferrarra ms. sensitivity of the concussion assessment battery. neurosurgery 2007;60(6):1050-1058. 14. shuttleworth-edwards ab, border ma. computer based screening in concussion management: use versus abuse. br j sports med 2002;36:473. 15. iverson gl, lovell mr, collins mw. immediate postconcussion assessment and cognitive testing (impact) normative data version 2.0. pittsburgh, usa: impact applications inc.; 2002. 16. shuttleworth-edwards ab, whitefield-alexander vj, radloff se, taylor am, lovell mr. computerized neuropsychological profiles of south african versus united states athletes: a basis for commentary on cross-cultural norming issues in the sports concussion arena. physician and sports med 2009;37(4):45-51. 17. lau b, collins m, lovell m. sensitivity and specificity of subacute computerized neurocognitive testing and symptom evaluation in predicting outcomes after sportsrelated concussion. am j sports med 2011;39(11):2311-2318 epub ahead of print. 18. thomas d, collins m, saladino r, frank v, raab j, zuckerbraun n. identifying neurocognitive deficits in adolescents following concussion. acad emerg med 2011;18(3):246-254. 19. echemendia r, herring s, bailes j. who should conduct and interpret the neuropsychological assessment in sports-related concussion. br j sports med 2009;43:i32i35. 20. mccrory p, meeuwisse w, johnston k, et al. consensus statement on concussion in sport: the 3rd international conference on concussion in sport held in zurich, november 2008. br j sports med 2009;43:i76-i84. introduction running, whether for recreation, fitness or professionally, has gained popularity all over the world. associated with this relatively inexpensive and popular code of sport, is the risk of injury. 6,13-15 it is clear that injuries sustained during running can be attributed to a wide range of causes and many of these have been the subject of investigation. 11,13-15,19 some studies have associated the risk of knee injury with the quadriceps (q)-angle. 9,12,19 van mechelen 19 has suggested that during running there is excessive use of the extensor mechanism of the knee resulting in an imbalance of the components of the quadriceps muscle. a stronger vastus lateralis pulls the patella laterally resulting in a larger q-angle, while a stronger vastus medialis pulls the patella medially resulting in a smaller q-angle. 2,4,8 therefore the q-angle is an indicator of the imbalance between components of the quadriceps muscle. the q-angle is the acute angle that is formed when the line connecting the anterior superior iliac spine (asis) and the midpoint of the patella intersects with the line connecting the tibial tubercle to the midpoint of the patella. the normal range for this angle in males is 10 22 degrees. 7,8,17,19 some studies 12,15,18,19 have found an association between running injuries and malalignment of the lower limb reflected in the q-angle. in south africa, no studies have reported on q-angles or the association between running injuries and the q-angle. therefore the purpose of the present study was to investigate the association between the q-angle and the prevalence of knee injuries in long-distance runners in durban, south africa. methods a list of long-distance indian male runners aged between 25 and 65 years registered with 5 athletic clubs in durban was obtained. from this list a random sample of 100 male runners was selected to participate in the study (20 subjects were chosen randomly from each of the 5 clubs). subjects gave fully informed voluntary consent. due to ethnic and gender differences in body stature and skeletal alignment, 16 participation was limited to south african males of indian descent. since durban is home to the majority of this population group in south africa, recruitment of subjects was facilitated. a peroriginal research article the quadriceps angle and the incidence of knee injury in indian long-distance runners t puckree (bsc physio, ms (exercise science), med, phd (exercise physiology))1 a govender (b physio)2 k govender (b physio)2 p naidoo (b physio)2 1 department of physiotherapy, university of kwazulu-natal, durban, and school of physiotherapy, sport science and optometry, university of kwazulu-natal, westville campus, durban 2 final-year physiotherapy students (at time of the study), department of physiotherapy, university kwazulu-natal, durban abstract objective. to investigate the incidence of knee injuries in runners and to determine the proportion of injuries involving abnormal quadriceps (q)-angles. design. one hundred male indian runners between the ages of 25 and 65 years from 5 athletic clubs in durban volunteered to participate in the study. the q-angle was measured using a goniometer. other relevant information was obtained using a validated questionnaire. the data were analysed by comparing measured q-angles with ‘normal’ values of q-angles obtained from the literature. a paired t-test at a probability of 0.05 was used. setting. data were collected at club meetings. main outcome measure. the primary outcome of the study was to determine the proportion of runners with abnormal q-angles. thereafter the rate of knee injuries in runners with abnormal q-angles was determined. results. data from 88 runners were usable. fifty-one per cent of the runners sustained knee injuries. fifty-eight per cent of the sample had abnormal q-angles. sixty-seven per cent of the runners with abnormal q-angles sustained knee injuries. conclusion. more runners with abnormal q-angles sustained knee injuries. there is a need to determine reference values for q-angles for the south african population, the proportion of the population that present with abnormal q-angles, and the reasons for this. correspondence: t puckree department of physiotherapy university of kwazulu-natal private bag x54001 durban 4000 tel: 031-260 7977/7817 fax: 031-260 8106 e-mail: puckreet@ukzn.ac.za sajsm vol 19 no. 1 2007 9 pg9-11.indd 9 4/4/07 10:28:52 am 10 sajsm vol 19 no. 1 2007 spex goniometer routinely used by physiotherapists was used to measure the q-angle as described below. three readings were taken successively, 1 minute apart while the subject assumed the supine position, to ensure test-retest reliability. a questionnaire with open and closed-ended questions was used to capture information relating to knee injuries and demographic details of the participants. the content validity of the questionnaire was checked through a pilot study using 5 non-participating runners. all subjects were accessed either at club meetings, time trials or during races. each participant signed a fully informed consent form. the study received ethical approval from the university of durban-westville ethics committee. measurement of the q-angle the q-angle was measured according to the method described by livingston and spaulding. 10 the subject lay supine on a plinth with the foot position standardised using a foot board. the anterior superior iliac spine (asis), the centre of the patella and the tibial tuberosity were marked using a kohl pencil. the centre of the goniometer was placed on the centre of the patella (found by intersecting width and length lines). the stationary arm of the goniometer was aligned with the asis and the movable arm was aligned with the tibial tuberosity. a third vertical line which extended from the tibial tuberosity along the femur allowed the formation of an angle. the acute angle formed was defined as the q-angle. three readings were taken for each subject by one investigator. the mean error was less than 0.01%. data analysis the average of 3 readings for each subject was used in the data analysis. these readings were compared with reference q-angles for male subjects as obtained from the literature. 17 a chi-square test was used to compare injured and uninjured runners with abnormal and normal q-angles, with p < 0.05. the data from the questionnaire were used to categorise the runners into 2 groups with and without knee injuries. knee injury in this study was defined as an injury to the knee requiring medical or other attention. each of these groups was stratified based on normal and abnormal q-angles, age, running experience, and knee pain. knee pain was defined as a reported perception of pain in the knee by the participants. results the participation rate was 100%. data analysis was carried out on the data from 88% of the participants. twelve per cent were excluded due to arthritis, deformities, and history of fractures. incidence of knee injuries was 51% (45 of the 88 runners). as shown in table i, 51 (58%) of the 88 runners had abnormal q-angles. sixty-seven per cent of these runners sustained knee injuries compared with 30% of runners whose q-angles were normal (p < 0.05). seventy-six per cent of the 34 injured runners with abnormal q-angles were between 36 and 60 years of age compared with 18% of the 11 injured runners with normal q-angles (p < 0.05). table i also shows that the proportion of injured runners (67%) was as high as the prevalence of abnormal q-angles (58%) (p < 0.05). training history did not affect the proportion of runners who were injured. sixty-three per cent of all the runners complained of knee pain. one hundred per cent of those with abnormal q-angles and only 11% of those with normal qangles complained of knee pain. the majority of those with knee pain and abnormal q-angles complained of anterior knee pain (57%). discussion the incidence of knee injuries in long-distance runners in the population under study was high and similar to that reported by van mechelen. 19 james 6 reported that the majority of running injuries occur at the knee. the q-angle has been found to influence lower extremity kinematics. 5 alteration in the q-angle changes the pattern of stress experienced by the patella cartilage 19 and thereby is the precursor to many knee injuries. imbalance of components of the quadriceps muscle, which insert on the patella can displace the patella, thereby effectively altering the q-angle. 4 hart et al. 3 found that fatigue of the lumbar paraspinal muscles reduced vastus lateralis activation. noakes 14 suggested that a pronated foot due to hypermobile feet could be implicated in knee problems. because the q-angle is formed between the vectors for the combined pull of the quadriceps femoris and the patella tendon, 9 the strength of the quadriceps muscle is important. our findings of significantly more injuries in persons with abnormal q-angles concur with those reported by lysholm and wiklander. 11 these researchers reported that 40% of knee injuries that occurred in running were caused by malalignment of the lower limb and in their case increased q-angles. in those runners aged 36 60 with abnormal q-angles, the table i. number and percentage of injured and uninjured runners with abnormal and normal q-angles by age group abnormal q-angle normal q-angle age (years) injured uninjured total injured uninjured total total 25 35 6 (46%) 7 (54%) 13 (25%) 2 (5%) 6 (16%) 8 (22%) 36 60 28 (76%) 9 (24%) 37 (73%) 2 (18%) 17 (46%) 19 (51%) 60+ 0 (0%) 1 (100%) 1 (2%) 7 (19%) 3 (8%) 10 (27%) total 34 (67%) 17 (33%) 51 (58%) 11 (30%) 26 (70%) 37 (42%) 88 pg9-11.indd 10 4/4/07 10:28:52 am incidence of knee injuries was higher than among those with normal q-angles. brill and macera 1 and van mechelen 19 suggest that normal younger-aged male runners train at higher speeds than their older counterparts thereby not allowing sufficient time for the adaptive process required in the musculoskeletal system. the age range of our runners with highest injury rate was 36 60. this age group is not young. a similar trend was observed for the younger age group, i.e. those between 25 and 35 years of age. muscular factors resulting in malalignment may contribute to running-related knee injuries. noble et al. 16 suggest that the size and shape of the human femur vary with gender, age, stature and ethnic background of the individual. the sample in this study included indian males over a range of ages. although the percentage of runners with abnormal q-angles was high, one cannot assume that this population group is different from other racial groups in this country, since no data exist to suggest this. although the data from this study on indian male runners concurs with that from other studies, 10,19 there is a need for more research in this area using samples from different race groups and genders in south africa. conclusion in this sample, abnormal q-angles were directly proportional to the incidence of knee injuries in long-distance runners. there is a need to first of all determine reference values for q-angles for the south african population by race, gender and age. the major determinants of abnormal q-angles can then be determined and rehabilitative strategies put in place. references 1. brill pa, macera ca. the influence of running patterns on running injuries. sports med 1995; 20: 365-8. 2. grelsamer gp, weinstein ch. applied biomechanics of the patella. clin orthop 2001; 389: 9-14. 3. hart jm, fritz jm, kerrigan dc, saliba en, gansneder bm, ingersoll cd. reduced quadriceps activation after lumbar paraspinal fatiguing exercise. journal of athletic training 2006; 41(1): 79-86. 4. hehne hj. biomechanics of the patellofemoral joint and its clinical relevance. clin orthop 1990; 258:73-85. 5. heiderscheit b, hamill j, caldwell ge. influence of q angle on lower extremity running kinematics. j orthop sports phys ther 2000; 5: 271-8. 6. james sl. running injuries to the knee. j am acad orthop surg 1995; 8:30918. 7. juhn ms. patellofemoral pain syndrome: a review and guidelines for treatment. am fam physician 1999; 60: 2012-22. 8. latinghouse lh, trimble mh. effects of isometric activation on the q-angle in women before and after quadriceps exercise. j orthop sports phys ther 2000; 30: 211-6. 9. livingston la. the quadriceps angle: a review of the literature. j orthop sports phys ther 1998; 28:105-9. 10. livingston la, spaulding sj. measurement of the q-angle using standardized foot positions. journal of athletic training 2002; 37:252-5. 11. lysholm j, wilkander j. injuries in runners. am j sports med 1987; 15:168-71. 12. macera ca. lower extremity injuries in runners. sports med 1992; 13(1): 50-7. 13. messier sp, davis se, curl ww, lowery rb, pack rj. etiologic factors associated with patellofemoral pain in runners. med sci sports exerc 1991; 23: 1008-15. 14. noakes t. the lore of running. leeds, uk: human kinetics, 2003. 15. nobel c. the pfizer manual of sports injuries. cape town: medical tribune publication, 1997: 40-63. 16. noble pc, box gg, kamarie e. the effects of aging on the shape of the proximal femur. clin orthop 1995; 3163: 1-44. 17. reider b, marshall jl, warren rf. clinical characteristics of patella disorders in young athletes. am j sports med 1998; 18:220-7. 18. taimela s, kujalo. m, oesterman k. intrinsic risk and athletic injuries. sports med 1990; 9:205-15. 19. van mechelen w. running injuries: a review of the epidemiological literature. sports med 1992; 14: 320-35. sajsm vol 19 no. 1 2007 11 pg9-11.indd 11 4/4/07 10:28:52 am sajsm vol. 25 no. 2 2013 55 review breast cancer is one of the most common cancers worldwide, and statistics reveal that the number of women diagnosed with breast cancer in south africa is increasing. as such, medical practitioners will treat an increasing number of breast cancer patients. although increasingly effective treatments improve patient survival intervals, a significant number of patients experience psychological distress, at the time of diagnosis and sometimes well beyond the start of treatment. this can be attributed to the disease itself and to treatment side-effects. historically, patients experiencing such distress have been treated with pharmacotherapy or have been referred for psychotherapeutic intervention. although it is well known that physical exercise is beneficial to physical health, only recently, and comparatively, has the effect of exercise been recognised as beneficial to psychological well-being. cancer patients are often advised to reduce physical activity to avoid cancer-related fatigue. paradoxically, recent research shows that physical exercise, of the type and intensity appropriate for the ability of each patient, can in fact play a significant role in improving mood and aiding physical recovery. this opens up a valuable additional resource to augment patients’ quality of life, both physically and psychologically. one precaution stands vitally important, however: the prescribed exercise regimen must be tailored to the physical capabilities of the patient. s afr j sm 2013;25(2):55-59. doi:10.7196/sajsm.481 exercise effects on mood in breast cancer patients h m van oers, ma (couns psych) durban oncology centre, durban, south africa corresponding author: h m van oers (fransvo@dtinc.co.za) with over 1 million new cases diagnosed worldwide per annum, breast cancer continues to be the most common cancer affecting women. unfortunately, surviving this cancer often means enduring significant and prolonged forms of adjuvant therapy, primarily radiation, chemotherapy and hormone therapy. these treatments, although increasingly effective in improving patient survival intervals, are toxic in numerous ways and produce negative shortand longterm physiological and psychological effects.[1] nearly all cancer survivors experience physiological and psychological symptoms and side-effects related to the disease or its treatment.[2] treatment-related symptoms, mood distress and decline in physical activity have all been found to be major problems encountered by cancer patients.[3] while mortality decreases, the increase in cancer incidence means that the number of women receiving adjuvant cancer treatment, and living with the associated side-effects, is increasing. therapyrelated negative side-effects include physiological and psychological symptoms such as pain, fatigue, muscle wasting, decreased cardiac function and psychological distress. each symptom can contribute to a significant impairment of quality of life (qol), and in some cases, affect prognosis.[3,4] depression is associated with chemotherapy non-compliance and reduced 5-year survival rates.[2] attention to psychological status is therefore an essential part of effective oncology treatment. however, in many instances, psychological distress is under-diagnosed and -treated due to time constraints, or because oncologists do not address or endorse this aspect of therapy. treatment effects on quality of life physiological sequelae differing treatment modalities can result in various physiological side-effects. chemotherapy (e.g. anti-metabolites, anthracyclines and alkylators) is used to control suspected micrometastatic disease and typically consists of 6 8 cycles of polychemotherapy administered over approximately 21 weeks. radiation is used following most breastconserving surgical procedures to control local disease and usually consists of daily treatment over a 6-week period. fatigue is a common side-effect of both of these treatment modalities.[5] chemotherapy has the further potential to cause decreased cardiorespiratory fitness and even cardiotoxicity in some patients, whereas radiation can also lead to irreversible lung fibrosis. oral hormone therapy (progestins or anti-oestrogens administered daily over a 5-year period) may cause ovarian ablation in pre-menopausal women, whereas the aromatase enzyme inhibitors prescribed for post-menopausal women may lead to fatigue and weight gain. physical and functional deficits may also include asthenia, ataxia, muscle weakness and atrophy, hair-loss, sleep disturbances, nausea and vomiting, and pain. many of these side-effects are common to patients with other cancers, but breast cancer patients face the additional burden of limited arm movement, lymphoedema of the arm, possible impaired cognitive function, weight gain and osteoporosis.[6] in combination, these co-morbid effects can have a significant negative effect on qol.[3,7] psychological sequelae recent studies have estimated the prevalence of depression, including major and minor depressive episodes and dysthymia, to be in the order of 20%, and the prevalence of anxiety disorders to be approximately 10%.[8] depression is characterised by feelings of sadness, hopelessness, changes in sleep and eating habits, psychomotor retardation and withdrawal from social contacts, which in turn lead to a deterioration of qol, and impaired social and occupational functioning. [7] cancer patients may show scores twice as high as those of the general population on the anxiety and depression subscales mailto:fransvo@dtinc.co.za 56 sajsm vol. 25 no. 2 2013 of the hospital anxiety and depression scale.[4] other psychological and emotional side-effects experienced by cancer patients include stress, fear of death, poor body image, low self-esteem, loneliness and a sense of loss of control over life.[2,3] one study[9] found a similar deterioration in fatigue and qol measures in breast cancer patients shortly after completing adjuvant therapies. qol impairment was also strongly associated with scores on depression, as well as fatigue.[9] despite an inconclusive relationship between psychological distress and cancer survival, a review of available research relating to breast cancer shows that most studies indicate a significant relationship between psychological factors and survival.[10,11] clinical depression is associated with non-compliance with cancer treatment and reduced survival, emphasising that depression negatively affects the psychological and physical health of many patients.[2,7] this underlines the role of psychological factors in cancer survival and emphasises the need for optimal supportive care to facilitate positive effects on such prognostic factors. it is clear that the appropriate management of psychological distress is of clinical importance, and it is vital that oncology healthcare professionals are aware of the importance of patients’ psychological functioning. current treatments for anxiety and depression in cancer patients include pharmacotherapy and psychotherapeutic interventions. for many, these treatments are safe, effective and provide significant improvements; however, there are some patients in whom these existing interventions are less effective due to personal, behavioural or organic factors. for example, selective serotonin-reuptake inhibitors (ssris) may be contraindicated in patients receiving hormone blockade therapies. in the general population, exercise acts as an effective antidepressant; it may therefore serve as an alternative form of treatment to provide symptom relief for depression and anxiety and improve physical health outcomes in cancer patients.[7,10] the effects of exercise on mood it is well known that physical exercise is beneficial to the body, but it is only recently, and comparatively, that the effect of exercise has been studied in terms of its effect on mood. mental and physical health are closely associated and can exert a significant effect on one another: mental health can be affected positively by physical exercise, and conversely, patients involved in physical rehabilitation tend to exhibit better compliance with, and make greater advances in treatment when they feel positive.[12] exercise increases blood flow and circulation, can improve memory function and provides a feeling of general well-being. there is growing evidence that physical activity and exercise have positive effects on mood in general, and on depression and anxiety in particular.[7,13-17] the manner in which exercise improves psychological well-being is explained by a neurobiological response and how physical exertion relates to the fight-or-flight response. most research has focused on hormonal reaction to increased physical activity, in particular the increased levels of beta-endorphins, encephalins, catecholamines and serotonin. endorphins are released by the pituitary gland during sustained vigorous exercise. these serve to reduce stress, decrease appetite and improve immune function. serotonin, together with norepinephrine, is a neurotransmitter that regulates mood and can affect anxiety mechanisms, thoughts and sleep patterns. studies have shown that low concentrations of serotonin cause symptoms of depression. the mechanisms involved in the increase of serotonin levels after exercise may be the result of motor activity increasing the firing rates of serotonin neurons, causing an increase in its release and synthesis. by increasing in concentration, these neurotransmitters serve to improve mood and decrease symptoms of depression.[2,18] in the general population, exercise is an effective antidepressant; individuals with moderate to more severe depression benefit comparably, and exercise is equally effective for men and women across a wide range of ages. these effects have been found to be comparable with psychotherapy and medication, particularly for those with mild to moderate depression.[7] the antidepressant effects of exercise have also been shown to last long beyond the exercise period.[13] yet, while the majority of studies concur regarding the positive effects of physical activity on mood, there is still uncertainty regarding which form of exercise is best for improving mood and mental health, and the specific effects of different types of exercise.[19] effects of different forms of exercise the main forms of exercise are aerobic and anaerobic. aerobic exercise occurs when oxygen is metabolised to produce energy. this is generally attained through sustained periods of hard work and vigorous activity lasting longer than 3 minutes at a time. anaerobic exercise refers to physical exertion where the energy required to produce this activity is provided independently of oxygen. this type of exercise uses short bursts of vigorous activity and typically lasts less than a minute. there are also alternative forms of activity that do not readily fall into the definitions of aerobic or anaerobic, but which also have the potential to affect mood and emotional well-being (e.g. yoga and meditation).[12] research suggests that aerobic exercise has the greatest moodelevating effects when performed continuously over an extended period of time, where the release of endorphins is responsible for the feel-good effect or ‘runner’s high’ that athletes experience after bouts of vigorous activity.[12] in addition to this endorphin-related positive effect, cortisol levels are altered by exercise: 30 minutes of moderate aerobic activity can reduce cortisol levels, higher levels of which are associated with negative affective states. this reduction may partly explain the moodelevating effects of physical activity. a factor influencing the degree to which aerobic exercise is beneficial appears to be the intensity: lowto moderate-intensity exercise has been shown to be effective in reducing both anxiety and depression,[20] whereas high-intensity exercise has been found in some instances to induce the opposite effect and increase levels of anxiety.[21] furthermore, moderate-intensity exercise may produce more sustained psychological benefits, probably because it is easier to maintain over longer periods of time.[12] it is generally believed that anaerobic exercise provides similar mood-enhancing effects to aerobic exercise only when performed at high-intensity levels. this is possibly due to the build-up of lactate in the muscles. while most studies show no difference between these two forms of exercise in terms of their mood-elevating potential, some studies have shown that anaerobic exercise does not confer the moodelevating effects attributed to aerobic exercise.[22] higher-intensity anaerobic exercises are more likely to lead to injuries, such as muscle tears and strains; as such, this aspect may outweigh its benefits with respect to positive emotional effects.[12] sajsm vol. 25 no. 2 2013 57 additionally, low-intensity aerobic exercises such as yoga and tai chi have been found to have positive effects on psychological functioning, leading to decreases in anxiety. tai chi, as a slower and less intense aerobic exercise, has been found to be a suitable alternative for patients not capable of more intensive exercise programmes.[12] exercise and the cancer patient until recently, patients were often advised to reduce their levels of physical activity and to seek more frequent periods of rest in order to counteract cancer-related fatigue. paradoxically, such a decrease in physical activity can, in fact, compound symptoms of fatigue, since a more sedentary lifestyle induces muscle catabolism and may cause further deficits in functional capacity. there is growing scientific evidence that exercise can substantially reduce cancer-related fatigue, which is linked to psychological distress, and improve qol.[23,24] several studies have shown that exercise is likely to mediate fatigue, anxiety, depression and qol in cancer patients.[3,7,25-27] one study found that exercise leads to significant decreases in fatigue, anxiety and depression in breast cancer patients receiving adjuvant therapy, with greater decreases with low weekly exercise doses. the study stated that a 20-week exercise programme comprised of a session of resistance training for principal muscle groups and 2 moderate-intensity aerobic sessions per week, each lasting 30 45 minutes, would be optimal in effecting positive mood change in these patients. this was found to be preferable to a higher-dose intervention.[4] another study found that lightto moderate-intensity aerobic exercise decreased anxiety in a sample of breast cancer patients, and indicated that this may be a valuable anxiolytic tool.[28] other research showed that exercise produced modest effects on depression in breast cancer patients across various disease stages. [7] nine studies of breast cancer patients were reviewed; all included programmes of aerobic and strength-training components initiated either prior to, or during adjuvant treatment. the review did not target depression through the selection of depressed cancer patients or by selecting exercises known to have the greatest effects on depression in other populations; therefore, in reality, the positive effects may be even greater for patients actually experiencing significant depression and targeted with exercise interventions effecting optimal change. these findings indicated that exercise produced the largest antidepressant effects when carried out over sessions longer than 30 minutes, and in terms of frequency, exercising 5 times per week was significantly more effective than 2 4 days weekly. in terms of intensity, it was found that lightto moderate-intensity exercise proved to be an effective antidepressant; with respect to breast cancer patients, light-intensity programmes are preferable as they are easier to incorporate into patient routines, and therefore result in greater compliance and exercise frequency. stagl[26] found that women who exercised the most between surgery and starting treatment were the least affected by depression and fatigue. more physically active patients tended to exhibit greater confidence in their ability to continue with their routine domestic, occupational and social activities. this, in turn, brought about greater feelings of satisfaction and led to appraisals of less depression and higher qol. the recommended levels of exercise were 20 minutes daily for the greatest benefit, but exercising every other day also proved to be therapeutic. the study emphasised that exercise can take many forms, e.g. jogging, cycling and swimming.[26] whereas most studies focus on exercise as a planned activity with the goal of achieving fitness, one study found that other forms of physical exertion, including occupational and household activities, were also effective in alleviating symptoms of psychological distress.[23] patients involved in any form of physical activity were less likely to report anxiety and depression in a preceding 30-day period, than those who were totally sedentary. the study found moderate-intensity activity to be optimal for breast cancer patients, with multiple short bouts of activity resulting in the greatest improvements.[23] regarding the aforementioned studies, the timing of exercise interventions and whether patients received adjuvant treatment in the post-diagnostic period need to be considered. some studies examined exercise effects in patients receiving adjuvant treatment, while the patients in other studies had completed active treatment. some research found that treatment status at baseline was not significant. this suggests that exercise may lessen symptoms of depression among patients who are undergoing treatment during exercise interventions, compared with those who are not. for many patients, depression may resolve after diagnosis and treatment, but for many it may persist or even develop after the treatment period is over.[7] while there is general consensus regarding the efficacy of exercise as a mediator of psychological distress in breast cancer patients, the majority of studies acknowledge that any form of recommended activity of necessity must consider the limitations placed on each patient in terms of their physical status in response to their disease and specific oncological treatment. recommendations should be tailored for each patient with respect to the intervention period, i.e. during v. postadjuvant therapy, in terms of the exercise type and intensity that the patient is able to tolerate. one study states that the specific beneficial effects of exercise, both during and after treatment, may vary as a function of the stage of disease, the nature of the medical treatment and the current lifestyle of the patient.[29] patients receiving adjuvant therapy experience patterns of fatigue that increase with chemotherapy cycles and peak 5 days after therapy administration. exercise programmes for such patients need to be adapted to progressively low to moderate doses of exercise across chemotherapy cycles, with fewer exercise sessions in the 10-day period following infusion, increasing to more frequently in the days thereafter. it has further been found that low doses of exercise (90 120 minutes of moderate exercise weekly) are more effective than higher doses.[4] breast cancer patients can adhere to a conventional exercise programme, even during adjuvant treatment. there is evidence to suggest that walking is the natural choice for most patients, and that cycle ergonometry offers the advantages of a sitting position and leg exercises (minimising ataxia, limitations in upper-body movement and lymphoedema). upper-body exercises are not contraindicated, but patients should be advised that wearing a compression sleeve on the arm of the affected side is a wise precaution.[27] cancer patients who are able to, should exercise aerobically (e.g. brisk walking or static cycling) for 20 60 minutes 3 5 days weekly. more debilitated patients should be advised to engage in several shorter exercise sessions per day, and that the exercise programme can progress as the patient becomes fitter. most importantly, the physician should always be aware that every patient will adapt differently to the exercise stimulus and goals; physical tolerance and age should determine individual rate of progress.[1] 58 sajsm vol. 25 no. 2 2013 some studies have found that the location and supervision of the exercise intervention are important; the greatest optimal effects have been observed in patients who participate in programmes that are supervised and exercise in facilities. home-based and unsupervised exercise interventions have, in fact, been associated with an increase in depressive symptoms.[2,7] contraindications to exercise medical screening is an essential aspect of prescribing an exercise programme for any cancer patient. several medical factors constitute general contraindications to exercise: cardiovascular insufficiency, such as acute myocarditis or recent myocardial infarction; acute infectious diseases; metabolic diseases such as thyrotoxicosis; and any physical impairment leading to inability to exercise.[1] in addition to these general contraindications, certain precautions are specific to cancer patients. exercise should be avoided 24 hours prior to intravenous chemotherapy. exercise should also be avoided at least 2 hours after either chemotherapy infusion or radiation therapy, as increased circulation may affect treatment. anaemic patients should avoid exercise until the anaemia has improved. onset of nausea during exercise and vomiting within 24 36 hours of exercise, feelings of unusual fatigue or muscle weakness, blurred vision, faintness or any pain unassociated with injury are also regarded as contraindications to continued exercise. in addition, immune-compromised patients should avoid public gyms until their white blood cell count returns to safer levels.[1] further research there is some disparity in the literature about the effectiveness of exercise in terms of different sub-populations. for example, age, socioeconomic status, ethnicity and employment status are not included or accounted for in the majority of studies. a recent study found that women of low socio-economic status with breast cancer have an increased risk of developing depression, and that the symptom burden may differ by socio-economic status and ethnicity. for example, older african-american patients who were unemployed were 3 times more likely to become depressed than those who were employed. another study found differences in levels of activity and qol between white breast cancer patients and patients from minority groups. physical activity was associated with increased qol in white patients, but not in minority group women.[30] more research is needed to better identify and treat breast cancer patients at risk for psychological distress. while there has been some research on the use of exercise as an intervention for breast cancer patients in south africa (sa), much of this literature is focused on the physiological improvements that an exercise intervention can confer within the context of physiotherapy and rehabilitation,[31] or the positive effects on brain function. [32] there seems to be a dearth of research into the efficacy of such interventions as a therapeutic option for psychological distress on the sa population; much less so on the oncology patient population, especially given the diversity of composite ethnicities, cultures and socio-economic groups. as stated above, several studies have noted that socio-economic and employment status as well as cultural factors were found to be considerations in terms of risk of depression and symptom burden. many sa patients may benefit considerably from an exercise intervention that may be more cost-effective and attainable than medication and has the benefit of providing a means of improving their health on multiple levels. conclusion it has been known for some time that physical activity exerts a positive effect on mood in the general population, and with later research, that it holds promise for improving symptoms of psychological distress in oncology patients. what is becoming increasingly clear is that exercise may be a valuable addition to the therapeutic resources of physicians and oncology healthcare professionals. where depression and anxiety in cancer patients have historically been treated using pharmacotherapy or psychotherapy, recommending an exercise programme may contribute significantly to physical and psychological well-being in a non-intrusive, non-toxic and accessible manner. importantly though, certain caveats remain: physical status must be regarded as paramount in terms of the type and quantity of exercise that the breast cancer patient is capable of performing, given the limitations imposed by surgery, lymphoedema, treatmentrelated fatigue and pre-diagnostic levels of fitness. further research is needed to identify appropriate exercise regimens for different subpopulations of breast cancer patients to optimise the benefits of such an intervention. references 1. rajarajeswaran p, vishnupriya r. exercise in cancer. ind j med paed oncol 2009; 30(2):6170. [http://dx.doi.org/10.4103%2f0971-5851.60050] 2. brown jc, huedo-medina tb, et al. the efficacy of exercise in reducing depressive symptoms among cancer survivors: a meta-analysis. plos one 2012;7(1). [http://dx.doi. org/10.1371/journal.pone.0030955] 3. yang cy, tsai jc, huang yc, lin cc. effect of a home-based walking program on perceived symptom and mood status in postoperative breast cancer women receiving adjuvant chemotherapy. j adv nurs 2011;67(1):158-168: [http://dx.doi.org/10.1111 /j.1365-2468.2010.05492] 4. carayol m, bernard p, boiche j, et al. psychological effect of exercise in women with breast cancer receiving adjuvant treatment therapy: what is the optimal dose needed? ann oncol 2013;24(2): 291-300. [http://dx.doi.org/10.1093%2fannonc%2fmds342] 5. schmidt me, chang-claude j, vrieling a, heinz j, flesch-janys d, steindorf k. fatigue and quality of life in breast cancer survivors: temporal courses and long-term pattern. j cancer surviv 2012;6(1):11-19. [http://dx.doi.org/10.1007%2fs11764-011-0197-3] 6. pinto ac, de azambuja e. improving quality of life after breast cancer: dealing with symptoms. maturitas 2011;70(4):343-348. [http://dx.doi.org/10.1016/j. maturitas.2011.09.008] 7. craft ll, vaniterson eh, helenowski ib, et al. exercise effects on depressive symptoms in cancer survivors: a systematic review and meta-analysis. cancer epidemiol biomarkers prev 2012;20(1):3-19. [http://dx.doi.org/10.1158%2f1055-9965.epi-110634] 8. mitchell aj, chan m, bhatti h, et al. prevalence of depression, anxiety and adjustment disorder in oncological, haematological and palliative care settings: a meta-analysis of 94 interview-based studies. lancet oncol 2011;12(2):160-174. [http://dx.doi. org/10.1016%2fs1470-2045%2811%2970002-x] 9. penttinen hm, saarto t, kellokumpu-lehtinen p, et al. quality of life and physical performance and activity of breast cancer patients after adjuvant treatments. psychooncology 2011;20(11):1211-1220. [http://dx.doi.org/10.1002/pon.1837] 10. chen x, lu w, zheng y, et al. exercise, tea consumption and depression among breast cancer survivors. j clin oncol 2010;28(6):991-998. [http://dx.doi. org/10.1200%2fjco.2009.23.0565] 11. falagas me, zarkadoulla ea, ioannidou en, et al. the effect of psychosocial factors on breast cancer outcome: a systematic review. breast cancer res 2007;9(4):r44. [http:// dx.doi.org/10.1186%2fbcr1744] 12. cohen g, shamus e. depressed, low self-esteem: what can exercise do for you? internet j allied health sci pract 2009;7:2. 13. scully d, kremer j, meade mm, graham r, dudgeon k. physical exercise and psychological well being: a critical review. br j sports med 1998;32:111-120. [http:// dx.doi.org/10.1136/bjsm.32.2.111] http://dx.doi.org/10.4103%2f0971-5851.60050] http://dx.doi.org/10.1371/journal.pone.0030955] http://dx.doi.org/10.1371/journal.pone.0030955] http://dx.doi.org/10.1111/j.1365-2468.2010.05492] http://dx.doi.org/10.1111/j.1365-2468.2010.05492] http://dx.doi.org/10.1093%2fannonc%2fmds342] http://dx.doi.org/10.1007%2fs11764-011-0197-3] http://dx.doi.org/10.1016/j.maturitas.2011.09.008] http://dx.doi.org/10.1016/j.maturitas.2011.09.008] http://dx.doi.org/10.1158%2f1055-9965.epi-11-0634] http://dx.doi.org/10.1158%2f1055-9965.epi-11-0634] http://dx.doi.org/10.1016%2fs1470-2045%2811%2970002-x] http://dx.doi.org/10.1016%2fs1470-2045%2811%2970002-x] http://dx.doi.org/10.1002/pon.1837] http://dx.doi.org/10.1200%2fjco.2009.23.0565] http://dx.doi.org/10.1200%2fjco.2009.23.0565] http://dx.doi.org/10.1186%2fbcr1744] http://dx.doi.org/10.1186%2fbcr1744] http://dx.doi.org/10.1136/bjsm.32.2.111] http://dx.doi.org/10.1136/bjsm.32.2.111] sajsm vol. 25 no. 2 2013 59 14. guszkowska m. effects of exercise on anxiety, depression and mood. psychiatr pol 2004;38(4):611-620. 15. strohle a. physical activity, exercise, depression and anxiety disorders. j neural transm 2009;116(6):777-784. [http://dx.doi.org/10.1007%2fs00702-008-0092-x] 16. hallgren ma, moss nd, gastin p. regular exercise participation mediates the affective response to acute bouts of vigorous exercise. j sports sci med 2010;9:629-637. 17. mchugh j, lawlor ba. exercise and social support are associated with psychological distress outcomes in a population of community-dwelling older adults. j health psychol 2012;17(6):833-844. [http://dx.doi.org/10.1177%2f1359105311423861] 18. young sn. how to increase serotonin in the human brain without drugs. j psychiatr neurosci 2007;32(6):394-399. 19. shamus e, russo sa, fields c, peal g, marikle sq, butler rd. exercise and mental health: psychological benefits. osteo fam phys news 2008;8(5):1-8. 20. rendi m, szabo a, szabo t, velenczei a, kovacs a. acute psychological benefits of aerobic exercise: a field study into the effects of exercise characteristics. psychol health med 2008;13(2):180-184. 21. bixby wr, hatfield bd. a dimensional investigation of the state anxiety inventory (sai) in an exercise setting: cognitive vs. somatic. j sport behav 2011;34(4):307-324. 22. callaghan p. exercise: a neglected intervention in mental health care? j psychiatr ment health nurs 2004;11:476-483. [http://dx.doi.org/10.1111%2fj.1365-2850.2004.00751.x] 23. basen-engquist k, hughes d, perkins h, shinn e, carmack taylor c. dimensions of physical activity and their relationship to physical and emotional symptoms in breast cancer survivors. j cancer surviv 2008;2(4):253-261. [http://dx.doi.org/10.1007%2 fs11764-008-0067-9] 24. arnold m, taylor nf. does exercise reduce cancer-related fatigue in hospitalised oncology patients? a systematic review. onkologie 2010;33(11):625-630. [http://dx.doi. org/10.1159%2f000321145] 25. loprinzi pd, cardinal bj. effects of physical activity on common side effects of breast cancer treatment. breast cancer 2012;19(1):4-10. 26. stagl jm. benefits of physical activity on depression and functional quality of life during treatment for breast cancer: psychosocial mechanisms. open access theses, 2011: paper 278. 27. courneya ks, mackey jr, mckenzie dc. exercise for breast cancer survivors: research evidence and clinical guidelines. phys sportsmed 2002;30(8):33-42. 28. blacklock r, rhodes r, blanchard c, gaul c. effects of exercise intensity and self-efficiency on state anxiety with breast cancer survivors. oncol nurs forum 2010;37(2):206-212. [http://dx.doi.org/10.1188%2f10.onf.206-212] 29. knols r, aaronson nk, uebelhart d, fransen j, aufdemkampe g. physical exercise in cancer patients during and after medical treatment: a systematic review of randomised and controlled clinical trials. j clin oncol 2005;23:3830-3842. [http://dx.doi. org/10.1200%2fjco.2005.02.148] 30. mandelblatt js, luta g, kwan m, et al. associations of physical activity with quality of life and functional ability in breast cancer patients during active adjuvant treatment: the pathways study. breast cancer res treat 2011;129(2):521-529. [http://dx.doi.org/10.100 7%2fs10549-011-1483-5] 31. derman ew, whitesman s, dreyer m, et al. healthy lifestyle interventions in general practice: part 5: lifestyle and cancer. sa fam pract 2009;51(2):91-95. 32. stein dj, collins m, daniels w, noakes td, zigmond m. mind and muscle: the cognitive-affective neuroscience of exercise. cns spectr 2007;12(1):19-22. http://dx.doi.org/10.1007%2fs00702-008-0092-x] http://dx.doi.org/10.1177%2f1359105311423861] http://dx.doi.org/10.1111%2fj.1365-2850.2004.00751.x] http://dx.doi.org/10.1007%2fs11764-008-0067-9] http://dx.doi.org/10.1007%2fs11764-008-0067-9] http://dx.doi.org/10.1159%2f000321145] http://dx.doi.org/10.1159%2f000321145] http://dx.doi.org/10.1188%2f10.onf.206-212] http://dx.doi.org/10.1200%2fjco.2005.02.148] http://dx.doi.org/10.1200%2fjco.2005.02.148] http://dx.doi.org/10.1007%2fs10549-011-1483-5] http://dx.doi.org/10.1007%2fs10549-011-1483-5] sajsm vol 24 no. 2 2012 55 original research noel pollock, paul dijkstra, rob chakraverty, bruce hamilton uk athletics, hospital of st john and st elizabeth, london, uk noel pollock, mb bch, msc, ffsem (uk), cesr paul dijkstra, mb chb, mphil, ffsem (uk) uk athletics, loughborough, uk rob chakraverty, mb bch, msc, ffsem (uk) qatar orthopaedic and sports medicine hospital, aspetar, qatar bruce hamilton, mb chb corresponding author: n pollock (npollock@uka.org.uk) low 25(oh) vitamin d concentrations in international uk track and field athletes introduction the epidemiology, clinical relevance and management of vitamin d deficiency are medical issues of both academic and public interest. the role of vitamin d in calcium regulation and bone health has been well established,1 but recent evidence has identified associations between vitamin d deficiency and cardiovascular disease, diabetes, autoimmune disease, cancer of the prostate, breast and colon, as well as all-cause mortality.2-11 as vitamin d has over 1 000 human genes as direct targets, including skeletal muscle, heart, lungs and adrenal medulla,12,13 there may be potentially significant consequences of vitamin d deficiency on athletic performance. however, there are very few publications about the prevalence of vitamin d deficiency in elite athletes or the effects of vitamin d deficiency on athletic performance. this is the first article regarding vitamin d status in elite track and field athletes. recent population studies have illustrated a significant prevalence of vitamin d deficiency in the general population,14-17 and athletes also seem to be susceptible.18-20 serum 25(oh)d is widely accepted as a biomarker for vitamin d status.21 while some debate persists as to optimal levels of 25(oh)d for health, it is generally accepted that levels of 20 30 mcg/l represent vitamin d insufficiency while levels below 20 mcg/l and 10 mcg/l are defined as deficient and severely deficient, respectively.10 vitamin d is unique among nutrients in that almost all diets contain very little vitamin d and production primarily occurs in the skin, after exposure to ultraviolet b (uvb) sunlight.10,22 vitamin d cannot be effectively absorbed in the autumn and winter months in the uk because of the angle of the sun and atmospheric uvb absorption.23,24 in the uk, reduced levels of 25(oh)d have been reported in a number of studies.25-28 a large study of postmenopausal women reported 77% of women with 25(oh)d levels <28 mcg/l.27 deficiencies have also been noted in 78% of patients attending a uk rheumatology clinic26 and over 90% of an asian cohort during a uk winter.25 it has been widely recognised that mean 25(oh)d levels are lower in dark-skinned individuals at all ages, with greater risk of insufficiency and deficiency.29-31 this racial difference is primarily due to increased melanin pigmentation which reduces uvb absorption and subsequent vitamin d production.32 however, with recent public health campaigns emphasising the dangers of sunlight exposure and advocating intensive sun-block cream use, reports have also found high insufficiency rates, of around 60%, in the uk caucasian population, and those with the fairest skin type to be, in fact, most deficient.28 there have been very few publications on vitamin d status in athletes. recently, in a study of 93 middle eastern male athletes, 91% were found to have a 25(oh)d level <20 mcg/l.18 a report of 18 abstract objective. while it is recognised that vitamin d deficiency is common in the general population, there have been no studies in elite athletes in the uk. this observational study aimed to assess the 25 hydroxy-vitamin d (25(oh)d) status of elite athletes on the great britain track and field team. methods. a cross-sectional observational study was performed by analysing blood results from elite athletes on the british athletics team (n=63; mean ± standard deviation (sd) age 24.9±4.2 years). athletes on the elite programme were offered blood tests through the winter and summer of 2009 and were eligible for inclusion in the study. results. nineteen per cent (n=12) of athletes in the current study can be classified as 25(oh)d deficient (<20 mcg/l), while a further 29% (n=18) can be classified as having insufficient serum 25(oh)d levels (20 30 mcg/l). female sex (insufficent and deficient oh(d) prevalence 58%, n=18) and dark skin (prevalence 65%, n=20) were found to be independent predictors of serum 25(oh)d levels of <30 mcg/l. conclusion. this study reveals a notable prevalence of low serum 25(oh)d levels in elite athletes and subsequent management of deficient athletes is likely to be of importance for athlete health. the impact of these results on athletic performance remains to be determined, and clinical trials to assess performance, particularly muscular performance, following correction of 25(oh)d status in deficient athletes are required. s afr j sm 2012;24(2):55-59. 56 sajsm vol 24 no. 2 2012 elite gymnasts in australia noted 9 to be vitamin d insufficient and a further 6 to be vitamin d deficient.19 in a study of 9 15-year-old finnish female athletes and non-athletes, 68% of all participants were found to have 25(oh)d levels <15 mcg/l.20 however, a small study on seven competitive road cyclists in the south of france identified adequate mean 25(oh)d levels of 32.4 mcg/l.33 while there are limited data on the effects of vitamin d deficiency on performance in athletes, the potential relationship with fracture risk34-36 and altered muscle function,37,38 in addition to the additional pathological associations noted above, would suggest that the identification and subsequent treatment of vitamin d deficiency in athletes is prudent. in the uk, track and field athletes would appear to be at significant risk of deficiency given the uk latitude (51 54°n), the indoor training environment and the proportion of dark-skinned athletes in the elite uk athletics track and field team. therefore, the aim of this study was to assess the 25(oh)d status of funded elite track and field athletes in the great britain team. methods participants all elite athletes funded on the uk athletics world class performance plan and training at uk athletics high performance athletics centres (n=80) were offered 25(oh)d testing throughout the 2008 2009 season as part of a routine blood screening programme. any athlete on this funded plan is considered to have the potential to win a medal at a world championship or the olympic games. no athletes were taking high-dose vitamin d (>1 000 iu/day) supplementation in the 3 months prior to the study. other vitamin or mineral supplementation, including calcium intake, was not recorded. the study group comprised all athletes who underwent the blood test between december 2008 and august 2009 (n=63) and completed informed written consent for the study. data collection age, sex and skin colour were recorded. skin colour was defined as either fair-skinned (white caucasian) or dark-skinned (afrocaribbean). the athlete’s place of residence and training location (indoor or outdoor) for the previous 2 months were also recorded. their competitive event was categorised as either endurance (race distances at or above 800 m) or sprint/power (all other track and field disciplines). the month of testing was recorded and categorised as either winter (december march) or summer (april august). blood sampling blood samples were collected by standard venepuncture using a 10 ml syringe and 23 gauge needle. there was no standard fasting procedure before testing. for athletes tested in birmingham (n=5) blood samples were analysed at the birmingham heartlands hospital, those in loughborough (n=17) at the leicester royal infirmary and those in london (n=41) were tested at the hospital of st john and st elizabeth. laboratories in london and loughborough used the same manufacturer’s chemiluminescent immunoassay (liason, diasorin® dartford, kent). no repeated sampling with the same athlete was done to compare different laboratories. the birmingham heartlands table 1. socio-demographics and other characteristics of the subjects variable frequency percentage gender females 31 49 males 32 51 endurance endurance 19 30 sprint/power 44 70 skin dark 31 49 fair 32 51 residence japan 1 2 london 32 51 midlands 17 27 north england 7 11 southern europe 2 3 southern usa 4 6 training environment indoors 20 32 outdoors 43 68 month of test dec 2 3 jan 9 14 feb 5 8 mar 8 13 apr 8 13 may 11 18 jun 8 13 jul 11 18 aug 1 2 season during test summer 39 62 winter 24 38 fr eq u en cy 10.0 5.0 0.0 0.00 20.00 40.00 60.00 80.00 vitamin d level (mcg/l) 3.2% 15.9% 10.0 20.0 28.6% 30.0 52.4% fig. 1. distribution of 25(oh)d level: deficient (vertical lines); insufficient (diagonal hash); sufficient (white). sajsm vol 24 no. 2 2012 57 hospital laboratory used an hplc tandem mass spectrometer (applied biosystems, warrington cheshire). insufficient 25(oh)d levels were defined as <30 mcg/l and deficiency as <20 mcg/l.10 statistical t-tests were performed to assess differences between the variables noted above, under data collection, and regression analysis was used to identify independent predictors for 25(oh)d deficiency. a p-value of <0.05 was considered significant. the independent predictors assessed by regression analysis were location, sex, training environment, skin colour, athletic event and season of testing. the study was granted ethical approval by queen mary’s university of london ethics panel (qmrec2010/84). results demographics sixty-three subjects (mean ± standard deviation (sd) age 24.9±4.2 years) had their serum 25(oh)d level measured. their sociodemographic and other characteristics are noted in table 1. all darkskinned athletes were afro-caribbean. seventeen athletes eligible for the study did not take up the offer of the blood test. 25(oh)d status in elite track and field athletes overall analysis identified a mean (±sd) serum concentration of 25(oh)d of 31.5±15.1 mcg/l (n=63). an insufficient 25(oh)d status was noted in 29% (n=18) of athletes and a further 19% (n=12) were deficient with levels <20 mcg/l (fig. 1). risk factors for low 25(oh)d status female athletes, dark-skinned athletes and those tested in the winter months were all noted to have significantly lower 25(oh)d levels (table 2). subsequent regression analysis, on variables of sex, age, location, season, skin colour and athletic discipline, identified female sex and dark skin as independent predictors for low 25(oh)d levels. analysis of the 15 dark-skinned athletes tested in the winter found 3 (20%) athletes to be insufficient and a further 8 (53%) deficient. in the summer 7 of 16 (44%) dark-skinned athletes were insufficient and 2 (13%) were deficient (table 3). of the tests performed on female athletes with dark skin 54% were deficient and a further 31% had insufficient levels. there were no male athletes with fair skin noted to be deficient (table 4). discussion this is the largest published study on 25(oh)d levels in elite international athletes. it provides clear evidence of a notable prevalence of 25(oh)d insufficiency and deficiency in elite uk track and field athletes. it should be recognised that this study is an observational cross-sectional study in our elite athlete group and there are no control group data from non-elite athletes or the general population. however, the aim of the study was to determine the prevalence of 25(oh)d deficiency in athletes. two differing laboratory techniques were used to determine 25(oh)d levels with the resultant possibility of inter-laboratory variability. there were no significant differences between the mean 25(oh)d levels in the groups assessed by each laboratory. the prevalence rates reported here support those of previous studies in young adults.17,39 in the usa and canada 36% of young adults have been noted to be deficient in the winter,39 which compares with our winter figure of 38%. our overall prevalence of deficiency throughout the year of 19%, with insufficiency in a further 28%, is similar to published work relating to adolescents in northern usa (latitude 42°n) which noted 24% of subjects with levels <15 mcg/l.17 by comparison, in middle eastern national level athletes from a variety of sports, 93% of athletes were noted to be deficient and, in australia, 33% of 18 gymnasts were found to be deficient.18,19 in our cohort, skin colour and sex were noted to be significant independent predictors of vitamin d status. the remarkable prevalence of deficiency in 54% of dark-skinned female athletes (and insufficient levels in a further 31%) is still comparable with some published literature in older groups of a similar skin colour.29 skin colour is well recognised as a predictor of vitamin d status with numerous studies identifying lower levels in individuals with dark skin.29-31 this is primarily due to increased melanin content reducing uvb absorption and subsequent vitamin d production.32 it has also been reported that seasonal table 2. differences in 25(oh)d levels by gender, event, skin colour, training venue and season 25(oh)d level (mean±sd), mcg/l p-value gender 0.014 male 36.1±15.7 female 26.8±13.2 event 0.509 endurance 33.2±11.1 sprint/power 30.8±16.7 skin colour <0.001 dark 24.9±11.0 fair 37.9±16.0 training venue 0.016 indoors 24.2±16.6 outdoors 34.9±13.3 season 0.005 summer 35.4±15.8 winter 25.2±11.8 table 3. proportion of vitamin d deficient and insufficient athletes by skin colour and season skin colour season n insufficient, n (%) deficient, n (%) dark-skinned winter 15 3 (20) 8 (53) dark-skinned summer 16 2 (13) 7 (44) fair-skinned winter 9 3 (33) fair-skinned summer 23 5 (22) 1 (4) table 4. proportion of vitamin d deficient and insufficient athletes by skin colour and gender skin colour gender n insufficient, n (%) deficient, n (%) dark-skinned female 13 4 (31) 7 (54) dark-skinned male 18 6 (33) 3 (17) fair-skinned female 18 5 (28) 2 (11) fair-skinned male 14 2 (14) 0 (0) 58 sajsm vol 24 no. 2 2012 differences in 25(oh)d levels, while apparent in other populations, is less evident in dark-skinned individuals.40 this is supported by our study, which found that season was not an independent predictor and prevalence of deficiency and insufficiency were similar in the darkskinned group throughout the year, presumably because of persisting reduction in cutaneous production. however, in addition to melanin content, social behaviour such as sun exposure and clothing should also be considered when reviewing an athlete’s risk of developing vitamin d deficiency. in studies of middle eastern groups, females have been reported to have significantly lower 25(oh)d levels.41-43 this has been attributed to required clothing covering all skin and thereby reducing exposure to uvb.44 in south africa, the mediterranean and other sun-rich areas the relevance of this study may not be immediately apparent. while individuals in sun-rich areas may be at less risk,45 a number of studies have shown a significant prevalence of vitamin d deficiency in these areas,46,47 potentially due to an individual’s skin colour or sunscreen application. our study findings would support the assertion that clinicians in any geographical area with a significant population of dark-skinned individuals should be mindful of the possibility of vitamin d deficiency. sex was a significant independent predictor in our study and this has been noted in other populations.48 it is possible that the application of sunscreen, uvb-blocking moisturiser or make-up may enhance the risk of developing deficiency. unfortunately we do not have information on hours of sun exposure or the use of sunprotection agents; further work is required. however, if these findings were corroborated in a larger athlete group, vitamin d deficiency may be an additional aetiological risk factor for the increased incidence of stress fractures in female athletes.49-54 insufficient serum concentration of 25(oh)d is known to increase parathyroid hormone (pth) secretion, increasing bone turnover and bone resorption.55 in a prospective study, in finnish army recruits, high serum pth levels were identified as a risk factor for stress fracture development.56 in two studies lower 25(oh)d levels have been found to be associated with a significantly increased risk of stress fracture in young finnish men57 and with high-grade stress fractures, in a large army cohort.58 one randomised controlled trial of more than 5 000 army recruits reports a reduction in stress fractures after daily supplementation of 2 g calcium and 800 iu vitamin d.59 in addition to the classic role in bone metabolism, vitamin d deficiency may directly impact on athletic performance through other physiological mechanisms including muscle function,38,60-62 immunity and the potential mediation of exercise-induced inflammation.63,64 the vitamin d receptor and intracellular vitamin d regulation have also been identified in heart muscle, liver, lung and adrenal systems, all of which are determinants of athletic performance.13,65,66 however, the direct evidence for treatment of vitamin d deficiency to improve performance is extremely weak. highquality trials in athletic populations are required to determine the effects of correcting vitamin d deficiency and insufficiency on athletic, and particularly muscular, performance. there remain many questions regarding optimal 25(oh)d serum concentration and management of deficiency in athletes, and indeed the wider population. management may include increased sunlight exposure, dietar y fortification and medication such as cholecalciferol. however, as this study reveals, athletes are at risk of 25(oh)d deficiency and, for the reasons discussed above, we recommend that sport and exercise medicine physicians are mindful of assessing vitamin d status. references 1. deluca hf. overview of general physiologic features and functions of vitamin d. am j clin nutr 2004;80:1689s-1696s. 2. autier p, 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caucasians: low vitamin d serum levels in fair skin types in the uk. plos one 2009;4:e6477. 29. nesby-o’dell s, scanlon ks, cogswell me, et al. hypovitaminosis d prevalence and determinants among african american and white women of reproductive age: third national health and nutrition examination survey, 1988-1994. am j clin nutr 2002;76:187-192. 30. meier de, luckey mm, wallenstein s, clemens tl, orwoll es, waslien ci. calcium, vitamin d, and parathyroid hormone status in young white and black women: association with racial differences in bone mass. j clin endocrinol metab 1991;72:703-710. sajsm vol 24 no. 2 2012 59 31. cosman f, nieves j, dempster d, lindsay r. vitamin d economy in blacks. j bone miner res 2007;22 suppl 2:v34-38. 32. clemens tl, adams js, henderson sl, holick mf. increased skin pigment reduces the capacity of skin to synthesise vitamin d3. lancet 1982;1:74-76. 33. maimoun l, manetta j, couret i, et al. the intensity level of physical exercise and the bone metabolism response. int j sports med 2006;27:105-111. 34. lehtonen-veromaa mk, mottonen tt, nuotio io, irjala km, leino ae, viikari js. vitamin d and attainment of peak bone mass among peripubertal finnish girls: a 3-y prospective study. am j clin nutr 2002;76:1446-1453. 35. bischoff-ferrari ha, willett wc, wong jb, giovannucci e, dietrich t, dawsonhughes b. fracture prevention with vitamin d supplementation: a meta-analysis of randomized controlled trials. jama 2005;293:2257-2264. 36. pasco ja, henry mj, kotowicz ma, et al. seasonal periodicity of serum vitamin d and parathyroid hormone, bone resorption, and fractures: the geelong osteoporosis study. j bone miner res 2004;19:752-758. 37. hamilton b. vitamin d and human skeletal muscle. scand j med sci sports 2010;20(2):182-190. 38. ceglia l. vitamin d and skeletal muscle tissue and function. mol aspects med 2008;29:407-414. 39. tangpricha v, pearce en, chen tc, holick mf. vitamin d insufficiency among freeliving healthy young adults. am j med 2002;112:659-662. 40. harris ss, dawson-hughes b. seasonal changes in plasma 25-hydroxyvitamin d concentrations of young american black and white women. am j clin nutr 1998;67:1232-1236. 41. allali f, el aichaoui s, saoud b, maaroufi h, abouqal r, hajjaj-hassouni n. the impact of clothing style on bone mineral density among post menopausal women in morocco: a case-control study. bmc public health 2006;6:135. 42. fonseca v, tongia r, el-hazmi m, abu-aisha h. exposure to sunlight and vitamin d deficiency in saudi arabian women. postgrad med j 1984;60:589-591. 43. hatun s, islam o, cizmecioglu f, et al. subclinical vitamin d deficiency is increased in adolescent girls who wear concealing clothing. j nutr 2005;135:218-222. 44. batieha a, khader y, jaddou h, et al. vitamin d status in jordan: dress style and gender discrepancies. ann nutr metab 2011;58:10-18. 45. poopedi ma, norris sa, pettifor jm. factors influencing the vitamin d status of 10-year-old urban south african children. public health nutr 2011;14:334-339. 46. linos e, keiser e, kanzler m, et al. sun protective behaviors and vitamin d levels in the us population: nhanes 2003-2006. cancer causes control 2012;23:133-140. 47. bener a, al-ali m, hoffmann gf. vitamin d deficiency in healthy children in a sunny country: associated factors. int j food sci nutr 2009;60 suppl 5:60-70. 48. daly rm, gagnon c, lu zx, et al. prevalence of vitamin d deficiency and its determinants in australian adults aged 25 years and older: a national, populationbased study. clin endocrinol (oxf ) 2011. [http://dx.doi.org/10.1111/j.13652265.2011.04320.x.] 49. jones bh, knapik jj. physical training and exercise-related injuries. surveillance, research and injury prevention in military populations. sports med 1999;27:111-125. 50. brudvig tj, gudger td, obermeyer l. stress fractures in 295 trainees: a one-year study of incidence as related to age, sex, and race. mil med 1983;148:666-667. 51. pester s, smith pc. stress fractures in the lower extremities of soldiers in basic training. orthop rev 1992;21:297-303. 52. evans rk, negus c, antczak aj, yanovich r, israeli e, moran ds. sex differences in parameters of bone strength in new recruits: beyond bone density. med sci sports exerc 2008;40:s645-653. 53. finestone a, milgrom c, evans r, yanovich r, constantini n, moran ds. overuse injuries in female infantry recruits during low-intensity basic training. med sci sports exerc 2008;40:s630-635. 54. popp kl, hughes jm, smock aj, et al. bone geometry, strength, and muscle size in runners with a history of stress fracture. med sci sports exerc 2009;41:2145-2150. 55. lips p. vitamin d physiology. prog biophys mol biol 2006;92:4-8. 56. valimaki vv, alfthan h, lehmuskallio e, et al. risk factors for clinical stress fractures in male military recruits: a prospective cohort study. bone 2005;37:267-273. 57. ruohola jp, laaksi i, ylikomi t, et al. association between serum 25(oh)d concentrations and bone stress fractures in finnish young men. j bone miner res 2006;21:1483-1488. 58. givon u, friedman e, reiner a, vered i, finestone a, shemer j. stress fractures in the israeli defense forces from 1995 to 1996. clin orthop relat res 2000:227-232. 59. lappe j, cullen d, haynatzki g, recker r, ahlf r, thompson k. calcium and vitamin d supplementation decreases incidence of stress fractures in female navy recruits. j bone miner res 2008;23:741-749. 60. sato y, iwamoto j, kanoko t, satoh k. low-dose vitamin d prevents muscular atrophy and reduces falls and hip fractures in women after stroke: a randomized controlled trial. cerebrovasc dis 2005;20:187-192. 61. bischoff-ferrari ha, conzelmann m, dick w, theiler r, stahelin hb. [effect of vitamin d on muscle strength and relevance in regard to osteoporosis prevention]. z rheumatol 2003;62:518-521. 62. bischoff ha, stahelin hb, dick w, et al. effects of vitamin d and calcium supplementation on falls: a randomized controlled trial. j bone miner res 2003;18:343-351. 63. liu pt, stenger s, li h, et al. toll-like receptor triggering of a vitamin d-mediated human antimicrobial response. science 2006;311:1770-1773. 64. willis ks, peterson nj, larson-meyer de. should we be concerned about the vitamin d status of athletes? int j sport nutr exerc metab 2008;18:204-224. 65. pfeifer m, begerow b, minne hw. vitamin d and muscle function. osteoporos int 2002;13:187-194. 66. nibbelink ka, tishkoff dx, hershey sd, rahman a, simpson ru. 1,25(oh)2-vitamin d3 actions on cell proliferation, size, gene expression, and receptor localization, in the hl-1 cardiac myocyte. j steroid biochem mol biol 2007;103:533-537. editorial 1 sajsm vol. 29 2017 new format of the south african journal of sports medicine the world of publishing scientific papers is constantly undergoing change. we are aware of this and adapting to meet the changing demands. instead of publishing four issues each year, we are going to publish the papers as soon as they are accepted for publication after going through peer review. the change has been implemented, so for 2017 there will be one. the number of papers we publish each year will remain the same or increase. this decision was taken after due consideration. journals published in paper form are dwindling as they are becoming too expensive to produce. electronic journals are flourishing. most of the established credible scientific journals have opted to be published electronically. some journals produce paper editions and electronic editions simultaneously. these are the wellfunded journals, usually attached to big publishing companies that have the financial and human resources to produce both forms of the journal. the south african journal of sports medicine, which started in 1982, has undergone change at critical times to meet the changing demands of the publishing industry. the journal was established to represent the south african sports medicine association (sasma), and was published in-house up until 1998. then it was published by the health & medical publishing group, along with 13 other smaller journals aligned to the health and medical fields. at the end of 2015 the financial model of this publishing company changed and the services offered became unaffordable to sasma. coincidently, at the same time the academy of science of south africa (assaf) put out feelers about journals wanting to manage themselves through the open journal systems (ojs) they supported. the ojs is a non-profit open source software which can be used to manage and publish journals. this is an alternative to commercial, for-profit online software. this was an attractive proposition for sasma because assaf is a credible organsisation. it is the only national science academy that is officially recognised by the south african government through the assaf act (act 67 of 2001). assaf’s main goal is to provide evidence-based scientific advice on issues of public interest to government and other stakeholders, and promote and apply scientific thinking in the service of society. therefore supporting journals and enhancing their quality falls within their mandate. assaf manages the scientific electronic library online (scielo sa; https://www.assaf.org.za). scielo sa is funded by the south african department of science and technology and endorsed by the south african department of higher education and training (dhet). scielo sa is a searchable full-text journal database in service of the south african research community. the database covers a selected collection of peer-reviewed south african scholarly journals and forms an integral part of the scielo brazil project (http://www.scielo.br). the scielo sa database had 65 journals from different disciplines; the south african journal of sports medicine is included in this list. all scielo sa journals appear on the web of knowledge (wok) search portal as the scielo citation index and are also found in the dhet list of approved journals. the dhet approved list is compiled annually from international and national journals. these accredited journals included in these lists are taken into account when the government subsidy is granted to universities for scientific publication of research output. i have explained this as background to the decision we have made about the new format of the journal. changing the format will not jeopardise our accreditation with the dhet. we are excited because we will be able to improve the quality of the journal with this new structure. our biggest goal is to reduce the reviewing time of a submitted paper. we also want to reduce the time-fromacceptance to time-to-online-publication. we obviously want to maintain a high standard and publish papers which are meaningful to the field of sport and exercise medicine and allied health sciences. we are confident that we will achieve all these goals with this new structure. mike lambert editor-in-chief s afr j sports med 2017;29:1. doi: 10.17159/2078-516x/2017/v29i0a2856 http://dx.doi.org/10.17159/2078-516x/2017/v29i0a2856 82 sajsm vol. 27 no. 3 2015 original research background. acute mountain sickness (ams) is an ever-increasing burden on the health sector. with reported incidences of greater than 50%, coupled with the fact that recreational activities at high altitude are gaining increasing popularity, more persons are developing ams. physicians are therefore increasingly faced with the task of managing and preventing ams. objectives. the pathophysiology of ams is poorly understood, with little understanding of risk factors for the development of ams. this research aimed to identify epidemiological and physiological risk factors for development of ams. methods. this study is a questionnaire-based study conducted in london and at everest base camp, in which 116 lowlanders were invited to participate and fill in a questionnaire to identify potential risk factors in their history that may have contributed to development of or protection against ams. results. a total of 89 lowlanders enrolled in the study. thirty-seven of the participants had ams at everest base camp, giving a prevalence of 42%. of the demographic variables, only weight and body mass index (bmi) were statistically significantly associated with ams, with those who weighed less or had a lower bmi more likely to get ams. previous high-altitude experience was also associated with ams, with those who had such experience less likely to get ams. conclusion. predicting ams and furthering our understanding of the pathophysiology of ams will be of tremendous benefit. further research is needed in this regard. s afr j sports med 2015;27(3):82-86. doi:10.7196/sajsm.8112 identifying risk factors that contribute to acute mountain sickness z mahomed,1 mb chb, fcem, mmed; d martin,2 phd; e gilbert,2 mb chb; c c grant,1 phd; j patricios,1 facsm, ffsem (uk); f motara,3 fcfp 1 department of sports medicine, school of medicine, faculty of health sciences, university of pretoria, south africa 2 centre for altitude, space and extreme environmental medicine, university college london, uk  3 division of emergency medicine, faculty of health sciences, univeristy of the witwatersrand, johannesburg, south africa corresponding author: z mahomed (zeynmahomed@gmail.com) acute mountain sickness (ams) is defined as the presence of a headache in an unacclimatised individual who has recently arrived at high altitude, along with gastrointestinal symptoms, insomnia, dizziness and lassitude or fatigue. [1] at the seventh international hypoxia symposium held at lake louise, canada,[2] ams was further subdivided into mild, moderate and severe, based on the clinical presentation. this formed the basis for the lake louise score, according to which mild ams is defined as headache, nausea, dizziness and fatigue during the first 12 hours after ascent to altitude. moderate ams occurs when there is moderate to severe headache with marked nausea, dizziness, lassitude, insomnia and fluid retention at high altitude for 12 hours or more. visitors to high altitude may also suffer from highaltitude cerebral oedema (hace) and high-altitude pulmonary oedema (hape). hape and hace are not severe forms of ams; they can exist in their own right without preceding ams and may have an entirely different pathophysiology. the pathophysiology of ams is not clearly understood. signals generated at high altitude may activate the trigeminovascular system (i.e. neurons in the trigeminal nerve that innervate cerebral blood vessels) by both chemical and mechanical stimulation, causing a headache.[3] many investigators believe that ams is due to mild cerebral oedema and that all new climbers to high altitude may have mild cerebral oedema. in those with moderate to severe ams, neuro-imaging demonstrated vasogenic oedema.[4] capillary leakage following hypoxia-induced damage to the blood-brain barrier also plays a role. mediators such as vascular endothelial growth factor, inducible nitric oxide synthase and bradykinin are also being studied. several risk factors for the development of ams have been identified; for example, speed of ascent greater than 300 500 m a day in the acclimatisation period, previous history of ams or hape, obesity, migraine, persistence of a patent foramen ovale, down syndrome, congenital pulmonary abnormalities, perinatal pulmonar y vascular insult, and holmes-adie syndrome, are clinical conditions associated with susceptibility to ams or hape. [5] this study was conducted at everest base camp, with an altitude of 5 364 m. the incidence of ams at everest base camp has been reported to be as high as 57%.[6] approximately ten people a year die on mount kilimanjaro alone. [7] millions of visitors travel each year to regions of high altitude, and the numbers are increasing as high altitude and extreme mountaineering become more accessible and ever more popular. it is evident that ams will prove to be an ever-increasing burden on the healthcare industry. identifying persons at increased risk of developing ams and at an increased risk of progressing to hace or hape will be invaluable to the high-altitude visitor as well as the healthcare professional. methods extreme everest 2013 was an observational cohort study of human responses to progressive hypobaric hypoxia (during ascent) and subsequent normoxia (following descent), comparing sherpas (highaltitude ancestry) with lowlanders (lowland ancestry). studies were conducted in london (35 m) in the uk and kathmandu (1 300 m), sajsm vol. 27 no. 3 2015 83 namche bazaar (3 500 m) and everest base camp (5 300 m) in nepal. of the 180 healthy volunteers departing from kathmandu, 64 were sherpas and 116 were lowlanders. this research is a questionnairebased study conducted in london and at everest base camp. all 116 lowlanders participating in the extreme everest 2013 study were invited to take part in this study and to complete a questionnaire to identify potential risk factors in their history that may have contributed to development of ams or protect against development of ams. this cross-sectional, single-site study was limited to adults who are literate in english. procedure and design at the testing sessions held at sea level in london volunteers were invited to participate in this study and to complete the study questionnaire. thus the initial part of the questionnaire was completed at sea level in london, with the lake louise score completed upon arrival at everest base camp. participants trekked in groups of up to 14. all lowlanders flew to kathmandu and spent one night there prior to flying to lukla (2 800 m). all participants followed an identical ascent and descent profile. the ascent to everest base camp from kathmandu was completed over 11 days, with rest days built into the schedule to reduce the likelihood of ams. the data collected in the questionnaire included the following: • biographical information: participant’s age, weight, height, gender, city of residence, previous high-altitude experience and previous episodes of ams. • family history: family history of heart attacks, cancer, high cholesterol, asthma, obesity, substance dependence, lung disease or high blood pressure. • personal medical conditions and medication use. • a lifestyle evaluation questionnaire including exercise and fitness, nutrition, tobacco use, alcohol and drug use, emotional health, safety and disease prevention. (this questionnaire was developed by the united states health and human services in 2006 so that the public perform self-evaluations on themselves.) • a nutritional assessment questionnaire, adapted to assess foodrelated behaviour in the athlete. the higher the score, the poorer the participant’s dietary habits. • the frequency, intensity, time (fit) index of kasari (unpublished master’s thesis, university of montana, missoula, 1976) which assesses frequency, intensity and time of exercise and sporting activity. this validated questionnaire was developed in the 1970s and shown to relate to aerobic fitness. it quantifies a respondent’s participation in any form of physical activity; with an increase in the frequency, intensity and time of exercise there is an accompanying increase in the index score and fitness. • the physical activity readiness score (par-q), a self-screening tool developed by the british columbia ministry of health and multidisciplinary board on exercise to identify individuals who may be not be suitable for commencing strenuous exercise. • the paffenbarger physical activity score, a short, selfadministered questionnaire designed to measure participation in leisure-time physical activity. it consists of eight questions relating to daily activity; a physical activity index can be computed from the answers, providing an estimate of energy expenditure. • the lake louise score.[2] statistical analysis categorical data were described using frequency (percentage) and continuous data using median (interquartile range (iqr)). for comparisons between the two ams groups (ams, no ams), the mann-whitney u-test was used for continuous variables and the χ2 test or fisher’s exact test in the case of small expected counts for categorical variables. the non-parametric mann-whitney u-test was used as the sample size was small and the distributions of variables were non-normal. all statistical analyses were performed using spss version 21.0 (ibm, usa). all tests were two-sided and a p-value <0.05 was considered to be statistically significant. ethical considerations all participants were provided with patient information leaflets and all submitted written consent. the study design, risk management plan and protocols were approved (in accordance with the declaration of helsinki) both by the university college london research ethics committee and the university college committee on the ethics of non-national health service human research, and the nepal health research council. results a total of 89 participants were enrolled into the study. the characteristics of the participants are presented in table 1. thirtyseven of the participants had ams at everest base camp, giving a prevalence of 42% (95% confidence interval (ci) 31 53%). for the demographic variables only weight (p=0.033) and body mass index (bmi) (p=0.047) were statistically significantly associated with ams. those participants who weighed less or had a lower bmi were more likely to get ams. previous high-altitude experience was also associated with ams (p=0.005), with those who had previous highaltitude experience less likely to get ams. none of the lifestyle evaluation subscale scores nor the overall lifestyle score was significantly associated with ams (p>0.05 for all). similarly, the nutritional assessment score and fit score were not significantly associated with ams (p=0.799 and p=0.817, respectively). those participants whose permanent residence was above 900 m (n=7) were less likely to get ams than those whose residence was at a lower altitude, but the difference was not statistically significant (p=0.233). similarly, those with a moderate paffenbarger physical activity score and those who achieved a pass on the readiness scale were less likely to get ams, but the results were not statistically significant (p=0.141 and p=0.188, respectively). the family medical histories of participants are presented in table 2. only a family history of heart disease was statistically significantly associated with ams (p=0.038), with those who had such a family history less likely to get ams. for the statistical analysis being overweight or obese were combined, and there was no statistically significant difference in bmi categories between the two ams groups (p=0.171, χ2 test). bmi was left as a continuous variable for the results presented, and the difference between groups was statistically significant (as can be seen from table 1). discussion this cross-sectional study was conducted with the aim of identifying factors associated with a person’s risk of developing ams. the 84 sajsm vol. 27 no. 3 2015 results largely conformed with those from existing research, with the exception of some interesting findings which will be discussed. does older age predispose one to developing ams? this study showed no statistically significant protective benefit conferred by table 1. participant characteristics overall and by ams group overall (n=89*) ams (n=37) no ams (n=52) p-value† n (%) gender 0.32 male 44 (49) 16 (43) 28 (54) female 45 (51) 21 (57) 24 (46) smoker 0.63 yes 14 (16) 5 (14) 9 (17) no 75 (84) 32 (86) 43 (83) height above sea level of permanent residence 0.23 < 900 m 79 (92) 34 (97) 45 (88) ≥ 900 m 7 (8) 1 (3) 6 (12) previous high-altitude experience 0.01 yes 54 (61) 16 (43) 38 (73) no 35 (39) 21 (57) 14(27) previous episode of ams 0.46 yes 8 (9) 2 (5) 6 (12) no 81 (91) 35 (95) 46 (88) paffenbarger physical activity score 0.14 low 7 (8) 4 (11) 3 (6) moderate 63 (71) 22 (59) 41 (79) high 19 (21) 11 (30) 8 (15) par-q readiness 0.19 pass 73 (82) 28 (76) 45 (87) fail 16 (18) 9 (24) 7 (13) median (iqr) age (yr) (n=86) 35 (28 51.3) 37.5 (28.3 50.5) 33 (27.8 -52.3) 0.66 weight (kg) (n=78) 73.5 (64 80.3) 68 (59 76) 75 (66 83.5) 0.03 height (cm) (n=74) 174.5 (165.8 180.3) 173 (163.5 180) 176 (166.5 181) 0.31 bmi (n=71) 23.3 (22.1 25.7) 22.9 (20.9 24.7) 23.9 (22.4 -27.1) 0.05 lifestyle evaluation (lower score is better) exercise/fitness score (possible range 4 12) 6 (4.5 8) 6 (4.5 8) 6 (4.3 8) 0.57 nutrition score (possible range 4 12) 7 (6 8) 7 (5.5 7) 7 (6 8) 0.14 tobacco use score (possible range 2 6) 2 (2 2) 2 (2 2) 2 (2 2) 0.74 alcohol and drugs score (possible range 4 12) 6 (4 7) 6 (4 7) 6 (5 7.8) 0.33 emotional health score (possible range 4 12) 5 (4 7) 5 (4 7) 5 (4 7) 0.73 safety score (possible range 5 15) 5 (5 6) 5 (5 6) 5 (5 6) 0.49 disease prevention score (possible range 5 15) 8 (7 9) 8 (6 8.5) 7.5 (7 9) 0.36 overall lifestyle score (possible range 28 84) 38 (36 43) 37 (34 43) 38.5 (36-43) 0.22 nutritional assessment score (possible range 15 75) 35 (27.5 39) 34 (28 38.5) 35 (27 39) 0.8 fit score (possible range 1 100) (n=77) 60 (48 80) 62 (48 80) 60 (48 80) 0.82 *unless otherwise stated. †all from mann-whitney u-test except for χ2 test and fisher’s exact test. sajsm vol. 27 no. 3 2015 85 age, at least in the range of 19 74 years. however, other studies have showed that increased age conferred some benefit at high altitudes. for example, roach et al.[8] studied the physiological and clinical response to moderate altitude (2 500 m) in 97 men and women aged 59 83 years, and found the incidence of ams to be 16%, lower than that reported for younger persons. even though 20% of the participants had coronary artery disease, 34% had hypertension and 9% had lung disease, the incidence of ams remained low. gaillard et al.[9] reported that people over the age of 55 years were 2.6 times less likely to suffer from ams than people younger than 25 years, further suggesting that age might be a protective factor in developing ams. a systematic review of the literature is required to answer this question definitively. to date studies have shown that ams is unrelated to gender. hackett et al.[10] studied 278 hikers at pheriche in nepal, and their results showed that gender did not predispose one to developing ams. honigman et al.[11] showed that women may be less susceptible to hape, but equally as prone to ams as men. wang et al.[12] also showed no difference in prevalence of ams between genders. similarly, there was no significant difference between genders in this study (p=0.324). neither the lifestyle evaluation subscale scores nor the overall lifestyle score was significantly associated with ams (p>0.05 for all). similarly, the nutritional assessment score and fit score were not significantly associated with ams (p=0.799 and p=0.817, respectively). physical fitness was also not shown to be protective against ams, which is in keeping with the literature. milledge et al.[13] showed no correlation between ams scores and hypoxic ventilatory response or vo2 max. one of the risk factors proposed by hackett et al.[4] is that of residing at an altitude below 900 m: those participants whose permanent residence was above 900 m (n=7) were less likely to get ams than those whose residence was at a lower altitude, but the difference was not statistically significant (p=0.233). a prior history of ams has been uniformly quoted as a risk factor by many authors. [1,8] this study showed that previous highaltitude experience was also associated with ams (p=0.005), with those who had previous high-altitude experience less likely to get ams. in this study participants who weighed less or had a lower bmi were more likely to get ams, which is in keeping with recent findings. richalet et al.[5] recently reported regular physical activity as a risk factor for development of ams. it would make sense that a fitter person with a lower bmi would do better at high altitude – but both richalet et al.[5] and this study have shown the opposite. this is an interesting subject to explore and investigate further. chronic medical conditions and a family history of conditions such as hypertension, coronar y arter y disease, mild chronic obstructive pulmonary disease and diabetes, as well as pregnancy, do not appear to affect susceptibility to high-altitude illness.[14] the family medical histories of the participants are presented in table 2. only a family history of heart disease was associated with ams (p=0.038), with those who had a family history less likely to get ams. smoking has not yet proven to be a risk factor for development of ams. gaillard et al.[9] studied two cohorts of 500 trekkers in the annapurna region of central nepal, and found no relationship between ams and smoking habits. similarly, no relationship between smoking and developing ams was found in this study (table 1). conclusion this study showed that certain parameters, such an increased weight, an increased bmi and previous altitude experience, decrease the risk of developing ams. lifestylescoring questionnaires did not predict those participants who might develop ams. furthermore, this study did not show a link between age, gender, fitness or smoking and the development of ams. with ever-increasing number of people visiting areas of high altitude, further research in this regard is anticipated to further expand our knowledge and understanding of ams. acknowledgements. xtreme everest 2 was supported financially by the royal free hospital nhs trust charity, the special trustees of university college london hospital nhs foundation trust, the southampton university hospital charity, the university college london institute of sports, exercise and health, the london clinic, university college london, university of southampton, duke university medical school, the united kingdom intensive care society, the national institute of academic anaesthesia, the rhinology and laryngology research fund, the physiological society, smiths medical, oroboros instruments, deltex medical, atlantic customer solutions, and the xtreme everest 2 volunteer participants who trekked to everest base camp. some of this work was undertaken at university college london hospital/university college london biomedical research centre, as well as at the university hospital southampton/ university of s outhampton respirator y biomedical research unit, both of which received a proportion of funding from the uk department of health’s national institute for health research biomedical research centre’s funding scheme. xtreme everest 2 is a research project coordinated by the xtreme everest oxygen research consortium, a collaboration between the university college london centre for altitude, space, and extreme environment medicine, the centre for human integrative physiology at the university of southampton and the duke university medical centre. table 2. family history overall and by ams group family history overall, n (%) (n=89) ams, n (%) (n=37) no ams, n (%) (n=52) p-value* any cancer 47 (53) 21 (57) 26 (50) 0.53 high blood pressure 27 (30) 9 (24) 18 (35) 0.30 high cholesterol levels 22 (25) 8 (22) 14 (27) 0.57 asthma 21 (24) 8 (22) 13 (25) 0.71 overweight 20 (23) 6 (16) 14 (27) 0.23 myocardial infarction 15 (17) 8 (22) 7 (14) 0.31 heart disease 13 (15) 2 (5) 11 (21) 0.04 lung disease 8 (9) 1 (3) 7 (14) 0.13 substance dependencies 4 (5) 0 (0) 4 (8) 0.14 *all from χ2 test except for fisher’s exact test. 86 sajsm vol. 27 no. 3 2015 membership, roles, and responsibilities of the xtreme everest 2 research group can be found at www.xtreme-everest.co.uk/team. members of the xtreme everest 2 research group: s abraham, t adams, w anseeuw, r astin, b basnyat, o burdall, j carroll, a cobb, j coppel, o couppis, j court, a cumptsey, t davies, s dhillon, n diamond, c dougall, t geliot, e gilbert-kawai, g gilbert-kawai, e gnaiger, m grocott, c haldane, p hennis, j horscroft, d howard, s jack, b jarvis, w jenner, g jones, j van der kaaij, j kenth, a kotwica, r kumar, j lacey, v laner, d levett, d martin, p meale, k mitchell, z mahomed, j moonie, a murray, m mythen, p mythen, k o’brien, i ruggles-brice, k salmon, a sheperdigian, t smedley, b symons, c tomlinson, a vercueil, l wandrag, s ward, a wight, c wilkinson, s wythe. scientific advisory board: m feelisch, e gilbert-kawai, m grocott (chair), m hanson, d levett, d martin, k mitchell, h montgomery, r moon, a murray, m mythen, m peters. references 1. mehta sr, chawla a, kashyap as. acute mountain sickness, high altitude cerebral oedema, high altitude pulmonary oedema: the current concepts. med j armed forces india 2008;64(2):149-153. [http://dx.doi.org/10.1016/s0377-1237(08)80062-7] 2. sutton j, coates g, houston c, eds. hypoxia and mountain medicine: proceedings of the 7th international hypoxia symposium, lake louise, canada. oxford: pergamon press, 1991:327-330. 3. sanchez del rio m, moskowitz ma. high altitude headache. lessons from headaches at sea level. adv exp med biol 1999;474:145-153. [http://dx.doi.org/10.1007/978-14615-4711-2_13] 4. hacket ph, yarnell pr, hill r, et al. high altitude cerebral edema evaluated with magnetic resonance imaging: clinical correlation and pathophysiology. jama 1998;280:1920-1925. [http://dx.doi.org/10.1097/00008506-199904000-00020] 5. richalet jp, larmignat p, poitrine e, et al. physiological risk factors for severe high altitude illness. am j respir crit care med 2012;185(2):192-198. [http://dx.doi. org/10.1164/rccm.201108-1396oc] 6. murdoch dr. symptoms of infection and altitude illness among hikers in the mount everest region of nepal. aviat space environ med 1995;66(2):148-151. 7. johnston j. the other side of the mountain. 2000. http://www.alpineascents.com/kiliarticle.htm (accessed 20 may 2012). 8. roach rc, houston sc, honigman b, et al. how well do older persons tolerate moderate altitude? west j med 1995;162(1):32-36. 9. gaillard s, dellasanta p, loutan l, et al. awareness, prevalence, medication use and risk factors of acute mountain sickness in tourists trekking around the annapurnas in nepal: a 12 year follow-up. high alt med biol 2004;5(4):410-419. [http://dx.doi.org/10.1089/ ham.2004.5.410] 10. hackett ph, rennie d, levine hd. the incidence, importance and prophylaxis of acute mountain sickness. lancet 1976;2(7996):1149-1155. [http://dx.doi.org/10.1016/ s0140-6736(76)91677-9] 11. honigman b, theis mk, koziol-mclain j, et al. acute mountain sickness in a general tourist population at moderate altitudes. ann intern med 1993;118(8):587-592. [http://dx.doi.org/10.7326/0003-4819-118-8-199304150-00003] 12. wang sh, chen yc, kao wf, et al. epidemiology of acute mountain sickness on jade mountain, taiwan: an annual prospective observational study. high alt med biol 2012;11(1):43-49. [http://dx.doi.org/10.1089/ham.2009.1063] 13. milledge js, beeley jm, broome j, et al. acute mountain sickness susceptibility, fitness and hypoxic ventilatory response. eur respir j 1991;4(8):1000-1003. 14. schoene rb. high altitude: an exploration of human adaption. integr comp biol 2002;42(4):910. [http://dx.doi.org/10.1093/icb/42.4.910] introduction the use of accelerometers by researchers to objectively monitor physical activity has seen a dramatic increase since 1997. 1 with the greater use of uni-axial accelerometers in large field studies, 2 important questions arise relating to possible sources of measurement error, such as monitor placement. 3,4 to date a number of laboratorybased studies have considered the effects of different placement positions on the output of uni-axial accelerometers 5,6 and the intraand inter-instrument variability of uni-axial accelerometers using mechanical settings 7-9 or motorised treadmill trials. 7,10-13 few studies have employed free-living protocols when evaluating the effect of placement position of movement monitors or the inter-instrument reliability of movement monitors. 5,14,15 only one free-living study has considered the placement position or inter-instrument reliability of uni-axial accelerometers by having subjects wear two monitors on either side of the hip. 14 that study was carried out in a highly urbanised setting, during the waking hours of one highly structured day, using students and staff from a university setting who were recreational runners and accumulated significant amounts of vigorous physical activity. 14 moreover, in their statistical analyses, mcclain et al. 14 did not report the possible effect of monitor placement on variance distribution 16 nor did they examine agreement 17 between the two placement positions. consequently, similar and more expanded analyses of free-living samples with more variable day-to-day physical activity patterns are required. importantly, rural subjects with low, recreational (vigorous) physical activity but high work-related (moderate) physical activity demands should be recruited. uni-axial accelerometers demonstrate low intra-unit variability but do exhibit inter-unit variability such that post-measurement adjustment in multivariate analysis has been used to account for this variance which could otherwise dilute the true relationship between a health outcome and accelerometer output. 18 in this regard, welk et al. showed that 0.9% of the variance for the raw counts obtained during multi-speed treadmill trials could be attributed to individual uni-axial accelerometer units. 6 there is thus a need to determine if this variance due to inter-unit variability is present or possibly even greater in free-living conditions than has been observed in laboratory trials. the objectives of this pilot investigation were firstly to evaluate the effect of monitor placement and monitor units on the variance distribution in relation to other sources of variance, and secondly to determine if monitor position had practically significant effects on reliability statistics, specifically in an adult population exhibiting low levels of vigorous, recreational physical activity but high levels of moderate work-related physical activity. original research article monitor placement, sources of variance and reliability of free-living physical activity: a pilot investigation abstract objectives. we investigated the effect of monitor placement on the sources of variance and reliability of objectively measured free-living physical activity (pa). design. a convenience sample (n=7; 3 females, 4 males) of rural, adult, black south africans was recruited from the plantation section of a local lumber mill. pa was assessed using two uni-axial accelerometers placed on the right hip (rh) and left hip (lh), over 3 weekdays. pa indices were total counts, average counts, inactivity (0 499 counts.min -1 ), moderate-1 activity (500 1 951 counts.min -1 ) and moderate-2+vigorous activity (≥1 952 counts.min -1 ). results. accelerometer output did not differ across trials for either hip placement (p>0.2). there were no significant differences between rh-lh for any accelerometer variable (p>0.1) and effect sizes were small (0.02 0.15). monitor position did not contribute any variance to accelerometer variables. variance due to monitor unit contributed <2% to raw and derived accelerometer variables. coefficients of variation derived from the standard deviation of rh-lh transformed differences ranged from 2.7% to 10.5%, except for moderate-1 and moderate-2+vigorous variables (16.0 72.8%). intraclass correlation coefficients (icc, rh-lh) were >0.90, except for moderate-1 time accumulated in bouts ≥10 min (icc=0.83). agreement between rh-lh for achieving cdc/ acsm pa guidelines was significant (kappa=0.79, p=0.002) conclusions. firstly there was no statistically significant difference between rh-lh for any accelerometer variable. secondly, accelerometer units accounted for little of the variance in accelerometer variables. thirdly, greater variability in monitor placement was apparent for moderate-1 and moderate-2+vigorous variables. correspondence: ian cook physical activity epidemiology laboratory university of limpopo (turfloop campus) po box 459 fauna park, 0787 polokwane, south africa tel+fax: +27 15 268 2390 e-mail: ianc@ul.ac.za ian cook (ba (phys ed) hons, bsc (med) hons)1 estelle v lambert (phd)2 1 physical activity epidemiology laboratory, university of limpopo (turfloop campus), south africa 2 mrc/uct research unit for exercise science and sports medicine, university of cape town medical school, south africa sajsm vol 21 no. 1 2009 13 methods study protocol the accelerometry data used in this analysis were collected during the validity trial of the international physical activity questionnaire (ipaq). 19-21 briefly, participants were recruited to wear two uni-axial accelerometers and contacted twice over an 8-day period. on the first occasion, subjects were recruited, provided anthropometric data and were instructed on the necessary procedures for wearing the accelerometers, one on either side of the hip (rh = right-hand side hip, lh = left-hand side hip). eight days later the accelerometers were collected. subjects received a small honorarium on completion of the study. signed informed consent was obtained from all participants. the study was approved by the ethics committee of the university of limpopo (turfloop campus). subjects a convenience sample of 7 black adult males (n=4, 30.0±0.8 yrs, 175.7±3.2 cm, 63.8±5.9 kg) and females (n=3, 38.7±7.0 yrs, 155.5±4.8 cm, 56.4±4.5 kg), resident on farms and villages, were recruited from the plantation section of a local lumber mill situated in rural limpopo province, south africa. all participants recruited were bmi <27 kg.m -2 . these forestry workers performed a variety of manual tasks and ensured that plantations were created and maintained, and that raw timber was harvested, sized, cleaned and stacked prior to transport to the saw mill for further processing. physical activity counts and durations to objectively quantify free-living physical activity of the subjects, two uni-axial accelerometers were worn for at least 8 days. the csa model 7164 (computer science applications, inc. shalimar, fl), now marketed as the mti actigraph (mti health services, fort walton beach, fl), is small and unobtrusive (5.1 cm x 4.1 cm x 1.5 cm, 42.6 g). 22 the accelerometers were worn on the rh and lh, securely attached to a nylon belt. the accelerometers could be removed for sleeping and bathing purposes by unclipping the nylon belt. subjects were carefully instructed as to the proper positioning of the accelerometers (mid-axillary line). the minute-by-minute data were downloaded from the accelerometers onto an ibm-compatible personal computer via an interface unit, for further analysis using proprietary software (daybyday.xls, microsoft excel 97 macro) and a customised data reduction programme (microsoft excel 2002 macro). physical activity counts were defined as total counts (counts. day -1 ) and average counts (counts.day -1 .min -1 = total counts/registered time for counts.min -1 ≥1). physical activity volumes (min.day -1 ) of inactivity and moderate and vigorous activity were derived using previously defined cut-points. 14,16 inactivity (lying, sitting, standing quietly, light activity) was classified as 0 499 counts.min -1 . for moderate activity (3 6 mets, 1 met = 1 metabolic equivalent = 3.5 mlo2.kg -1 .min -1 = 1 kcal.kg -1 .hr -1 ) a distinction was made between activities requiring less ambulation (moderate-1: house work, yard work) and predominantly ambulatory activities (moderate-2: walking). the cut-points for moderate-1 and moderate-2 were defined as 500 1 591 counts.min-1 and 1 592 5 724 counts.min -1 , respectively. activities, such as running, which record ≥5 725 counts.min -1 were defined as vigorous (>6 mets). the amount of activity accumulated in bouts of ≥10 min (bouts separated by at least 1 min) for the moderate-1 and moderate-2+vigorous categories were also derived. the first and last days of the 8-day monitoring period were excluded. only weekdays with at least 8 hours.day -1 (480 minutes.day -1 ) of registration (counts.min-1 ≥1) were considered. this would represent the minimum of a 40-hour, 5-day working week in this sample. valid accelerometer data for the first 3 weekdays were used for all subsequent analyses. a 3-weekday period was selected because 3 subjects provided a minimum of 3 weekdays of valid accelerometer data. statistical analysis descriptive statistics comprised means and standard deviations. if data distribution was non-normal, the parametric results were confirmed with transformed (natural logarithms) or ranked data. data were analysed using appropriate statistical software (spss for windows 13.0). confidence intervals (95%ci) were calculated as required. significance for all inferential statistics was set at p<0.05. to evaluate the sources of variability in accelerometer data, variance components in mixed effects models were estimated using restricted maximum likelihood methods. 16 accelerometer raw output and derived indices were the dependant variables for these analyses. variance components were estimated for subject (interindividual) variance, monitor unit variance (8 units), trial variance (3 trials), monitor position variance (2 positions), and residual (intraindividual) variance. the variance components were expressed as a percentage of the total variance. inter-individual variance represents true variation between subjects while intra-individual variance represents day-to-day variation within subjects. the variance due to monitor unit, trial and monitor position effects were nested within subjects. gender and day of the week were entered as fixed factors. using the same set of fixed and random factors, a separate analysis was performed on the raw accelerometer data (counts.day -1 ) to test for possible interaction of subjects by monitors. 11 a multivariate, two-way repeated-measures anova was used to examine possible differences across trials for rh and lh accelerometer variables. separate analyses were conducted with gender entered as a between-subjects factor, and interactions between gender and hip placement or trial. in order to compare the accelerometer output between rh and lh, the mean difference and limits of agreement for repeated measurements were calculated for all accelerometer variables. 17 we did not use the rh and lh withinsubject variances across trials to adjust the variance of differences. within-subject variances for any accelerometer variable did not differ significantly between rh and lh (p>0.4) such that any adjustment using within-subject variance would simply inflate the variance of differences. this inflation would simply mean that within-subject variance across trials was greater than the rh-lh difference variance. bland-altman plots and q-q normal probability plots of difference scores were constructed to visually assess the limits of agreement and distribution of difference scores, respectively. 17 for comparative purposes 14 we also calculated a coefficient of variation (cv) from the standard deviation of the differences of the transformed raw data (natural logarithms) using the following formula (cv = 100 x [e sd -1]). 23 because the moderate-2+vigorous (bouts ≥10 min) contained zero values, we added one to all raw values before taking the natural logarithms of the raw values. effect sizes (d) were calculated from the mean difference and the standard deviation of the differences obtained during the limits of agreement analysis (raw values), and interpreted according to cohen’s conventions; 0.20 (small), 0.50 (moderate), 0.80 (large). 24 the iccm (intraclass correlation coefficient; average measure, absolute agreement, two-way random effects) 25 was calculated (rh v. lh) for each trial. thereafter, the mean iccm was calculated from the iccm of three trials. subjects were also classified according to the acsm/cdc guidelines (≥30 min.day -1 of moderate-2+vigorous activity accumu14 sajsm vol 21 no. 1 2009 lated in bouts ≥10 min) 26 for each trial and monitor position. agreement between rh and lh for each trial (7 pairs of data) and for all trials combined (21 pairs of data) was assessed by constructing 2-by-2 tables and calculating cohen’s kappa (κ) statistic. results six of the 8 units were used twice; once on the rh and once on the lh. registered time for counts ≥1 ranged from 8.12 hrs to 14.45 hrs (10.18±1.75 hrs) and did not differ significantly between rh and lh monitors (rh: 10.18±1.91 hrs; lh: 10.18±1.63 hrs; mean difference = -0.01 hrs, p=0.9771). there was no significant difference across trials for registered time for rh or lh monitors (p>0.2). descriptive statistics for rh and lh accelerometer raw output and derived variables are reported in table i. because the volume of vigorous activity accumulated was low (rh: 6±12 min.day -1 , lh: 6±11 min.day -1 ) and distribution was skewed, a separate variable was constructed which combined moderate-2 and vigorous activity. repeated-measures analyses found no significant differences across the three trials for any accelerometer variable (p>0.1) nor any significant differences between hip placement or gender for any accelerometer variable (p>0.4), except for moderate-1 (bouts ≥10 min) where females accumulated significantly more activity than males (34 min, p=0.0081) (table i). there was no interaction between gender and trial or hip placement (p>0.2). there was no marked difference in significance using the raw data or rank transformed data for the moderate-2+vigorous (bouts ≥10 min) variable, consequently the p-values from the raw data are reported. effect sizes for the mean differences between rh and lh ranged from d=0.02 to d=0.15 (small effect) for all accelerometer variables. the 95% limits of agreement in table i represent the area within which 95% of the mean differences would be expected to fall, if the differences are normally distributed. 17 the difference scores (rh minus lh) were randomly distributed irrespective of the magnitude of the accelerometer variables and the difference scores were normally distributed (data not shown). agreement analysis revealed no systematic bias in mean differences for any accelerometer variables. limits of agreement were similar for moderate-1 and moderate-2+vigorous variables (table i). the distribution of variance is reported in table ii. monitor position did not contribute to the variability of any of the accelerometer variables. the variability due to individual monitor units was 0.3% to 1.7% for raw and derived accelerometer data. there was no interaction for subjects-by-monitors. inter-individual variance was table i. descriptive statistics for accelerometer raw output and derived indices raw output and derived monitor positions agreement ‡‡ indices right-hand side hip ** left-hand side hip** significance †† total counts * 761 635 (212 074) 763 290 (178 772) 0.2755 -1 655 (-151 016 to 147 706) average count † 999 (215) 1 008 (177) 0.2376 -9 (-140 to 122) inactivity ‡ § 1 026 (102) 1 024 (91) 0.6197 +2 (-50 to 54) moderate-1 ‡ || (bouts ≥1 min) 284 (62) 285 (59) 0.1305 -1 (-33 to 30) (bouts ≥10 min) 44 (23) 46 (19) 0.1854 -2 (-24 to 20) moderate-2 + vigorous ‡ ¶ (bouts ≥1 min) 130 (50) 131 (40) 0.1529 0 (-36 to 35) (bouts ≥10 min) 19 (22) 20 (18) 0.9841 -1 (-20 to 19) * total counts = cts.day -1 , † average counts = cts.day -1 .min -1 ; ‡ activity duration = min.day -1 ; § 0-499 cts.min -1 ; || 500-1 951 cts.min -1 ; ¶ ≥1 952 cts.min -1 ; ** estimated marginal mean (sd) of three trials; †† trial main effect p-value; ‡‡ mean difference (95% limits of agreement), main effect significance for hip differences p>0.7. table ii. variance component analysis of 3-day accelerometry raw output and derived variables activity duration * activity counts * moderate-1 moderate-2 + vigorous sources of variance † total average inactivity bouts ≥1 min bouts ≥10 min bouts ≥1 min bouts ≥10 min inter-individual 79.0 67.1 68.4 60.7 23.5 68.8 53.8 intra-individual 21.0 32.9 31.6 39.3 76.5 31.2 46.2 position ‡ 0.0 0.0 0.0 0 0.0 0.0 0.0 trial § 3.1 7.3 23.7 29.1 10.1 8.2 0.0 monitor | 1.7 0.0 0.7 0 0.3 0.0 0.0 residual 16.2 25.6 7.2 10.2 66.1 23.0 46.2 total 100 100 100 100 100 100 data reported as a percentage of total variance; * see table i for units and cut-point definitions; † adjusted for gender and day of the week; ‡ position (right-hand side, left-hand side); § trial (1, 2, 3); | monitor (8 units). sajsm vol 21 no. 1 2009 15 greater than intra-individual variance for all accelerometer variables, except the moderate-1 (bouts ≥10 min) variable. of all the variance components nested within-subjects, trial contributed the most. there was no marked difference in variance components using the raw data or rank transformed data for the moderate-2+vigorous (bouts ≥10 min) variable, consequently the variance from the raw data is reported in table ii. the variance components reported in table ii for the moderate-1 (bouts ≥10 min) variable was obtained from natural logarithm transformation. the reliability analysis is reported in table iii. cv ranged from 2.7% to 10.5% for raw and derived variables, except for moderate-1 and moderate-2+vigorous variables (16.0% to 72.8%). iccm for four of the six accelerometer variables were >0.90. the iccm for trial 1 and trial 3 of the moderate-1 (bouts ≥10 min) variables were low and insignificant, resulting in a low mean iccm. transforming the moderate-1 (bouts ≥10 min) data did not improve the results. the high intrato inter-subject variance ratio for the moderate-1 (bouts ≥10 min) data (table ii) would account for the continuing low iccm. in contrast, the low iccm for the moderate-2+vigorous (bouts ≥10 min) reported in table iii was the result of averaging an insignificant iccm for trial 1 and significant iccm for trials 2 3. rank transforming the moderate-2+vigorous (bouts ≥10 min) data resulted in significant reliability coefficients (consistency, two-way random effects) for all trials (p≤0.01) resulting in a mean iccm=0.92. 25 only two subjects were misclassified in terms of achievement of acsm/cdc guidelines between rh and lh monitors; one subject on trial 1 and one subject on trial 3. there were no misclassifications for trial 2. agreement between hip positions was significant for trial 2 (κ=1.00, p=0.0082) but not trials 1 and 3 (κ=0.70, p=0.05334). overall (trial 1-3) agreement was significant (κ=0.79, p=0.0002). discussion this study is the first analysis, albeit preliminary in nature, which has reported on the effect of monitor placement on the variance distribution and reliability of uni-axial accelerometer output and derived variables obtained during free-living conditions in a south african setting. the principal findings of this analysis were firstly that there were no statistically significant differences between hip positions for raw or derived accelerometer variables. secondly, greater variability was apparent for the moderate-2+vigorous variables, especially so for time accumulated in bouts ≥10 min for both moderate categories. thirdly, individual accelerometer units accounted for nearly 2% of the variance for raw accelerometer counts. welk et al. were the first to demonstrate that at a moderate treadmill walking speed of 4.8 km.hr -1 , different uni-axial accelerometer hip positions (anterior axillary, mid-axillary, posterior axillary) had a significant effect (p<0.05) on accelerometer output (cts.min -1 ) such that variability (percentage of mean score) was 30% compared with 3% for two other accelerometers (biotrainer and tritrac). 6 these findings suggest that variability is more likely to increase at moderate intensities during free-living trials where monitor position is not accurately controlled. our results are in agreement with laboratory treadmill studies that have found greater variability between uni-axial accelerometers mounted across hips (rh v. lh) at moderate intensities compared with vigorous intensities. 7,10 nichols et al. found lower reliability across hip placement for slow speeds (icc=0.55, 3.2 km.hr -1 ) compared with faster speeds (icc=0.91, 6.4 km.hr -1 ).7 similarly, brage et al. demonstrated lower agreement at moderate walking speeds (4 6 km.hr -1 ) compared with faster running speeds (8 14 km.hr -1 ), even though icc>0.91. 10 importantly, these differences remained even after calibration of the individual monitors. the effect of hip v. lower back positions on uni-accelerometer output has been investigated during laboratory treadmill 5 and freeliving trials. 5,15 yngve et al. reported significant differences (p<0.01) between hip and lower back positions for normal and fast walking and jogging (4.3, 5.8 and 9.6 km.hr -1 , respectively) irrespective of setting (indoor athletics track or treadmill). 5 the absolute percentage error (|[hip – back/back]| x 100) was greatest for the normal to fast walking (9.5% and 7.2%, respectively) which occurred in the moderate (1 952 5 724 cts.min -1 ) range, and lowest for jogging (4.5%; ≥5 725 cts.min -1 range). it was suggested that the differential findings between walking and jogging were due to changes in vertical displacement of the hip compared with the lower back during the transition from fast walking to jogging. 5 during a 7-day free-living trial, no significant difference was found between monitor positions (10 cts.min -1 , p=0.23, 95% limits of agreement: -102 to 82 cts.min -1 ). moreover, the amount of daily moderate-to-vigorous time predicted from four mets v. cts.min -1 equations did not differ between monitor positions. 5 during a 4-day free-living trial in children, nilsson et al. demonstrated no difference between hip and lower back positions for raw counts (22 cts.min -1 , p=0.20, 95% limits of agreement: -110 to 154 cts.min -1 ). 15 the wide limits of agreement was due to 2 subjects and might have been caused by specific movements that result in differences in movements between the hip and lower back. a significant difference (p<0.01) between output for hip and lower back positions was found only when data were sampled over short periods (5 sec epochs) and only in the moderate range (1 952 5 725 table iii. reliability analysis of 3-day accelerometry raw output and derived indices intraclass correlation coefficient ‡ raw output and derived indices * coefficient of variation † trial 1 trial 2 trial 3 mean || total counts 10.5 0.95 0.97 0.96 0.96 average counts 6.3 0.98 0.92 0.96 0.95 inactivity 2.7 0.93 0.98 0.94 0.95 moderate-1 (bouts ≥1 min) 5.7 0.86 0.99 0.98 0.94 (bouts ≥10 min) 33.8 0.72 § 0.78 0.39 § 0.63 moderate-2 + vigorous (bouts ≥1 min) 16.0 0.96 0.89 0.96 0.94 (bouts ≥10 min) 72.8 0.61 § 0.92 0.95 0.83 * see table i for units and cut-point definitions; † percentage; ‡ average measure intraclass correlation coefficient for rh v. lh; all trial icc significant (p<0.02) except § p=0.08; || arithmetic mean for trial 1-3. 16 sajsm vol 21 no. 1 2009 cts.min -1 ). short sampling periods might be more likely to capture even small differences in movement at different body sites. 15 more recently, mcclain et al. have been the first to show that in free-living conditions, rh-lh comparisons exhibit greater variability for the moderate-2 range (500 1 951 cts.min -1 ), 14 thus confirming the laboratory treadmill findings of greater variability at walking speed intensities. 7,10 our results are in accord with the lower variability reported by mcclain et al. for total counts, inactivity and moderate-1 variables. 14 however, in contrast to mcclain et al., we have found higher variability for the moderate-2+vigorous physical activity (mvpa) categories (≥1 952 cts.min -1 ; bouts ≥1 min and ≥10 min). 14 these apparently contradictory findings are due to the selective subject recruitment strategies employed in this study and by mcclain et al. 14 mcclain et al. purposively selected highly active individuals (runners), which resulted in approximately 65% of mvpa time being accumulated from vigorous activity (≥5 725 cts.min-1). 14 consequently, the increased variability of the moderate-2 range was diluted by the larger contribution of the vigorous range. the present study, on the recommendation of mcclain et al., 14 selected subjects who were not vigorously active but rather accumulated activity in the moderate-1 and moderate-2 activity zones. this is evident by a 3-fold greater moderate-1 time, a nearly 5-fold greater moderate2 time and an 8-fold lower vigorous time, compared with mcclain et al. 14 moreover, the moderate-2 zone in this study contributed approximately 95% to the mvpa variable. consequently, in contrast to mcclain et al., 14 we do not recommend collapsing moderate-2 and vigorous activity zones into a single mvpa variable as a method to dilute greater variability from the moderate-2 zone. we would caution researchers that the creation of an mvpa variable does not always imply a reduced variability as suggested by others. 14 taken together these studies have shown that uni-axial accelerometer counts sampled during moderate intensities are more variable when collected at different body sites. 5-7,10,14,15 however, none of these studies investigated the effect of body sites on moderate-to-vigorous time accumulated in bouts ≥10 min and on the compliance of subjects with pa public health guidelines. consequently, contrary to the assertion by trost et al. that the practical effect of different body sites on uni-axial accelerometer output is negligible, 3 we would argue that there is still uncertainty as to the practical effects of mounting uni-axial accelerometers at different body sites. although we could not calibrate the units before and during the field measurements, post-measurement variance analysis showed that 1.7% of the variability for total daily counts could be attributed to monitor units, which is in agreement with the 0.9% found by welk et al. during multi-speed treadmill trials. 11 the twofold increase in variability compared with welk et al. might be due to the greater time spent at low and moderate intensities in this sample and the freeliving conditions. importantly, the 14.5 20.1% variance for the trialby-subject and monitor-by-trial-by-subject interaction reported by welk et al. suggests differences by subject due to clothing, posture and other anthropometric variations, which could be amplified during free-living trials due to lack of standardisation. 11 moreover, brage and associates have shown greater inter-unit variability at low to moderate intensities 9,10 and it has been suggested that real anatomical differences such as body size, hip geometry and hip softtissue deposition might explain acceleration differences between hip positions at lower movement intensities, specifically slow to normal walking. 10 we reanalysed uni-axial accelerometer data from a recently reported variance component analysis 27 and found that accelerometer units accounted for 0% and 5.8% of the total variance of daily counts in rural and urban subjects, respectively. it is possible that the greater time spent in low-to-moderate activities (low accelerations) by the urban subjects would result in greater inter-instrument variability. 9,10 this could in turn account for the increased accelerometer unit variability in urban subjects. our results and those of others 9-11 highlight the need to make post-measurement statistical adjustments for monitor units if individual calibration of units cannot be performed before and during field trials. 9,10,18 our finding of a substantial within-subject variance for the moderate-1 (bouts ≥10 min) in comparison with other variables is difficult to explain. we reanalysed uni-axial accelerometer data recently reported for a larger rural sample out of which the current sample was drawn. 27 as with the current analysis, the betweenand within-subject variance was 30% and 70%, respectively. further analyses are required to determine whether the variance distribution for this particular accumulated uni-axial accelerometer variable is due to a bias resulting from the creation of a variable accumulated from bouts of pa ≥10 min or is a reflection of a true behavioural characteristic of the subjects. the strengths of the present pilot study are firstly the uniqueness of the analysis within a south african context. secondly, this analysis provides reliability and variance estimates for a south african sample with particularly high occupational physical activity demands. thirdly, this study has also been the first to show dramatically increased variability for time in moderate intensity variables accumulated in bouts ≥10 min. further research is required to confirm this increased variability, and possible causes for this phenomenon. the weakness of this study is firstly that we could not differentiate between mechanical or anatomical causes for the increased variability of uni-axial accelerometer output at low to moderate intensities. however, no study to date has been able to quantify the separate contributions of mechanical and anatomical causes to increased variability across hip placement. secondly, our sample size was limited when investigating the effects of monitor position variability on the compliance with public health pa guidelines. in conclusion, this analysis has demonstrated that uni-axial accelerometer placement across hips has a greater effect on variability for derived duration variables in the moderate intensity range. this increased variability resulted in statistically small effects, and future research should consider investigating the effects of uni-axial accelerometer placement on bouts of activity and the consequent compliance with pa guidelines. as part of quality control procedures, researchers should perform similar analyses when conducting field trials, and should either regularly calibrate individual accelerometer units or adjust statistically post-measurement when relating accelerometer output to a health outcome. acknowledgements the research development and administration division of the university of limpopo (turfloop campus) and the research capacity development group of the medical research council of south africa supported this study. references 1. troiano rp. a timely meeting: objective measurement of physical activity. med sci sports exerc 2005;37:s487-s489. 2. troiano rp. large-scale applications of accelerometers: new frontiers and new questions. med sci sports exerc 2007;39:1501. sajsm vol 21 no. 1 2009 17 3. trost sg, mciver kl, pate rr. conducting accelerometer-based activity assessments in field-based research. med sci sports exerc 2005;37: s531-s543. 4. welk gj. principles of design and analyses for the calibration of accelerometry-based activity monitors. med sci sports exerc 2005;37:s501s511. 5. yngve a, nilsson a, sjostrom m, ekelund u. effect of monitor placement and of activity setting on the mti accelerometer output. med sci sports exerc 2003;35:320-326. 6. welk gj, blair sn, wood k, jones s, thompson rw. a comparative evaluation of three accelerometry-based physical activity monitors. med sci sports exerc 2000;32:s489-s497. 7. nichols jf, morgan cg, chabot le, sallis jf, calfas kj. assessment of physical activity with the computer science and applications, inc., accelerometer: laboratory versus field validation. res q exerc sport 2000;71:36-43. 8. metcalf bs, curnow js, evans c, voss ld, wilkin tj. technical reliability of the csa activity monitor: the earlybird study. med sci sports exerc 2002;34:1533-1537. 9. brage s, brage n, wedderkopp n, froberg k. reliability and validity of the computer science and applications accelerometer in a mechanical setting. meas phys educ exerc sci 2003;7:101-119. 10. brage s, wedderkopp n, franks pw, andersen lb, froberg k. reexamination of validity and reliability of the csa monitor in walking and running. med sci sports exerc 2003;35:1447-1454. 11. welk gj, schaben ja, morrow jr. reliability of accelerometry-based activity monitors: a generalizability study. med sci sports exerc 2004;36:1637-1645. 12. rowlands av, stone mr, eston rg. influence of speed and step frequency during walking and running on motion sensor output. med sci sports exerc 2007;39:716-727. 13. trost sg, ward ds, moorehead sm, watson pd, riner w, burke jr. validity of the computer science and applications (csa) activity monitor in children. med sci sports exerc 1998;30:629-633. 14. mcclain jj, sisson sb, tudor-locke c. actigraph accelerometer interinstrument reliability during free-living in adults. med sci sports exerc 2007;39:1509-1514. 15. nilsson a, ekelund u, yngve a, sjostrom m. assessing physical activity among children with accelerometers using different time sampling intervals and placements. pediatr excer sci 2002;14:87. 16. matthews ce, ainsworth be, thompson rw, bassett dr. sources of variance in daily physical activity levels as measured by an accelerometer. med sci sports exerc 2002;34:1376-1381. 17. bland jm, altman dg. measuring agreement in method comparison studies. stat methods med res 1999;8:135-160. 18. brage s, wedderkopp n, ekelund u, et al. features of the metabolic syndrome are associated with objectively measured physical activity and fitness in danish children: the european youth heart study (eyhs). diabetes care 2004;27:2141-2148. 19. bohlmann im, mackinnon s, kruger s, et al. is the international physical activity questionnaire (ipaq) valid and reliable in the south african population? med sci sports exerc 2001;33:s119. 20. cook i, lambert ev. validity and reliability of the international physical activity questionnaire in northern sotho-speaking africans. jemdsa 2002;7:36. 21. craig cl, marshall al, sjostrom m, et al. international physical activity questionnaire: 12-country reliability and validity. med sci sports exerc 2003;35:1381-1395. 22. welk gj. use of accelerometry-based activity monitors to assess physical activity. in: welk gj, ed. physical activity assessments for health-related research. champaign, il: human kinetics; 2002. p.125-141. 23. hopkins wg. measures of reliability in sports medicine and science. sports med 2000;30:1-15. 24. cohen j. statistical power analysis for the behavioral sciences. 2nd ed. new york: academic; 1988. 25. mcgraw ko, wong sp. forming inferences about some intraclass correlation coefficients. psychol methods 1996;1:30-46. 26. pate rr, pratt m, blair sn, et al. physical activity and public health. a recommendation from the centers for disease control and prevention and the american college of sports medicine. jama 1995;273:402-407. 27. cook i, lambert ev. the sources of variance and reliability of objectively monitored physical activity in rural and urban northern sotho-speaking africans. s afr j sports med 2008;20:21-27. 18 sajsm vol 21 no. 1 2009 10 sajsm vol 24 no. 1 2012 original researchoriginal research introduction injury surveillance is fundamental for preventing and reducing the risk of injury. as a result injuries in adult cricketers have been well researched over the years with long-term injury surveillance being carried out in australia,1 england2 and south africa.3 the findings of these studies report that bowlers were at the greatest risk of injury, sustaining between 40% and 45% of the injuries, followed by fielders, including wicket-keepers (25 33%) and then batsmen (17 21%). these injuries were predominantly to the lower limbs (45 49%), back and trunk (18 23%) and upper limbs (23 29%). the injuries were predominantly sustained during matches (52 58%) and occurred during the early part of the season (35%). between 65% and 92% of the injuries sustained were new injuries, with between 8% and 22% being recurrent injuries from the previous season and 12% recurring in the same season. of the injuries, 65% were of an acute nature, with 23% chronic and 12% of an acute-on-chronic nature. the primary mechanism of injury was the delivery and follow-through in bowling (25%), running, diving, catching and throwing (23%) and overuse (17%). soft-tissue injuries were the most common, with the most likely sites to be injured being the thigh and calf (25%), fingers (14%) and lumbar spine (11%). similarly, in a study on west indies cricketers 68% of injuries occurred during matches, with bowlers (46%) and batsmen (40%) more likely to sustain muscle (26%), ligament (12%), stress fractures (12%) and fractures (10%).4 while injuries in adult cricketers have been well documented in the literature, there remains a paucity of literature on injuries, injury patterns and risk factors in young cricketers. a study by stretch5 reported that the high seasonal incidence of injuries to schoolboy cricketers was similar to that of a previous study on club and provincial cricketers.6 the overall seasonal incidence of injury was found to be 49%, with the most common site of injury the back and trunk (33%), upper limbs (25%) and the lower limbs (23%). bowlers (47%) were at greater risk of injury than the batsmen (30%) and fielders (23%). the injuries occurred equally during matches (46%) and practices (47%), with 30% being recurrent injuries from the previous season and 37% of the new injuries recurring during the same season. in an intervention study aimed at reducing the risk of injury to fast-bowlers, dennis et al.7 monitored 12and 17-year-old cricketers playing club and district cricket over a season to evaluate the recommended bowling workloads in young cricketers.7 the findings revealed a relationship between a high bowling workload and injury. of the 44 bowlers, 11 reported over-bowling-related injuries, with 7 sustaining back-related injuries. the injured bowlers bowled more frequently and had shorter rest periods between bowling sessions than the uninjured. the bowlers with an average of more than 3.5 rest days between bowling were at significantly less risk of injury than those with an average of less than 3.5 rest days. the results showed a 3-year investigation into the incidence and nature of cricket injuries in elite south african schoolboy cricketers richard a stretch (d phil) chris trella (ba hons) nelson mandela metropolitan university, port elizabeth, south africa correspondence to: richard stretch (richard.stretch@nmmu.ac.za) abstract objectives. injury surveillance is fundamental to preventing and reducing the risk of injury. the aim of this study is to determine the incidence of the injuries sustained by elite schoolboy cricketers over three seasons (2007 2008, 2008 2009, 2009 2010) to identify possible risk factors. methods. sixteen provincial age-group cricket teams (under 15, under 17 and under 18) competing in national age-group tournaments were asked to complete questionnaires to obtain the following information for each injury: (i) anatomical site; (ii) month; (iii) cause; (iv) whether it was a recurrence of a previous injury; (v) whether the injury had reoccurred again during the season; and (vi) biographical data. injuries were grouped according to the anatomical region injured. all players were requested to respond, irrespective of whether an injury had been sustained. the sample statistical analysis system (sas) was used to compute univariate statistics and frequency distributions. of the 1 292 respondents 366 (28%) sustained a total of 425 injuries. the u15 and u17 groups sustained 166 (39%) and 148 (35%) injuries, respectively, more than the 111 injuries sustained by the u18 group (26%). these injuries were predominantly to the lower (46%) and upper (35%) limbs and occurred primarily during 1-day matches (31%), practices (27%) and with gradual onset (21%). the primary mechanism of injury was bowling (45%) and fielding, including running to field the ball (33%). forty-two lumbar muscle strains, 18 hamstring strains, 17 spondylolisthesis and 17 ankle sprains occurred. the injuries were acute (50%), chronic (42%) and acute-on-chronic (8%), with 24% and 46% being recurrent injuries from the previous and current seasons, respectively. results. similar injury patterns occurred in studies of adult cricketers, with slight differences in the nature and incidence of injuries found for the various age groups. the u15 group sustained less serious injuries which resulted in them not being able to play for between 1 7 days (54%), with more injuries occurring in the pre-season period (28%) than the other groups. the u17 group sustained the most lumbar muscle strains (n=23), while the u18 group sustained more serious injuries with 60% of the injuries resulting in them not being able to play for 8 or more days. conclusion. young fast-bowlers of all ages remain at the greatest risk of injury while slight differences in the nature and incidence of injuries occurred in the different age groups. it is recommended that cricket administrators and coaches need to implement an educational process of injury prevention and management. sajsm vol 24 no. 1 2012 11 an increase in risk of injury for bowlers who bowled more than 50 deliveries per day and who bowled on average more than 2.5 days per week. bowling was the primary cause of injuries in a group of 196 elite schoolboy cricketers taking part in the 2004 national u19 cricket week. the primary mechanism of injury occurred during the delivery stride and follow-through when bowling at pace. most of the injuries were first-time injuries (87%) with 41% severe enough to prevent the players from practising or playing for more than 21 days.8 a total of 46 young fast-bowlers between the ages of 11 and 18 years were assessed with a view to determine the injury profile and associated risk factors during a season.9 fifteen of the bowlers remained injury-free during the season, with the most common injury to the knee (41%) and the lower back (37%). the injuries occurred primarily during mid-season and were mainly strains (39%). the results also indicated the multifactorial role that inadequate fitness, high bowling workloads and bowling techniques play in predisposing a young fastbowler to risk of injury. it is not appropriate to use the data from adult injury surveillance studies to design coaching and training programmes to reduce injuries in young cricketers. thus, the aim of this study was to determine the seasonal incidence of injuries and possible risk factors sustained by elite schoolboy cricketers and to identify possible differences between players of different age groups. method the sample consisted of provincial cricketers competing in three national age-group cricket tournaments (u15, u17 and u18). ethics approval for this study was obtained from the nelson mandela metropolitan university’s ethics committee. a questionnaire was handed out to all the players by the team coach and they were required to complete the questionnaire, irrespective of whether an injury had been sustained or not. the questionnaire was designed to obtain the following information for each injury: (i) anatomical site; (ii) month; (iii) cause; (iv) whether it was a recurrence of a previous injury; (v) whether the injury had reoccurred again during the season; and (vi) biographical data. as this study required the player to recall the injuries from the previous season it was dependent of his understanding and interpretation of his medical practitioner’s diagnosis. no other medical records or records of other sports played were obtained. an injury was defined as an injury that prevented a player from being fully available for selection for a match or which prevented the player from completing the match, with all injuries classified according to the osics injury classification system.10 for purposes of this survey the incidence of injury was expressed as a percentage of the total number of injuries recorded. injuries were grouped according to the anatomical region injured as follows: (i) head, neck and face; (ii) upper limbs; (iii) back and trunk; and (iv) lower limbs. injuries were classified table 1. injuries for the u15, u17 and u18 age groups u15 u17 u18 total # % # % # % # % players no injuries 281 66 279 69 306 76 866 70 injured 146 34 125 31 95 24 366 30 injuries sustained 166 39 148 35 111 26 425 100 one injury 130 31 104 24 81 19 315 74 two injuries 24 6 38 9 24 6 86 20 three injuries 12 3 6 1 6 1 24 6 season and number of injuries 2008 32 8 18 3 32 8 82 19 one injury 26 16 26 68 two injuries 6 2 6 14 three injuries 2009 49 12 57 13 24 6 130 31 one injury 42 47 18 107 two injuries 4 10 6 20 three injuries 3 3 2010 85 20 73 17 55 13 213 50 one injury 62 41 37 140 two injuries 14 26 12 52 three injuries 9 6 6 21 *as a result of rounding the percentage do not always add up to 100%. 12 sajsm vol 24 no. 1 2012 according to whether they were sustained during batting, bowling, fielding (including catching and wicket-keeping), fitness training and ‘other’. the time of the year when the injury occurred was recorded, with the off-season being the time of the year when no specific cricket practice or matches took place (april july). the pre-season (august and september) was the part of the year when specific cricket training and practice was undertaken in preparation for the season and before the commencement of matches. the season (october march) was defined as the period when matches were played. in order to allow comparisons to be made between the phases of play during which the injuries were sustained, the number of injuries was expressed as a percentage of the total number of injuries sustained. similarly, to allow comparisons to be made between the injuries sustained by the players in the various age groups, the number of injuries was expressed as a percentage of the number of injuries sustained in that particular age group. the sample statistical analysis system (sas) was used to compute univariate statistics and frequency distributions. results of the 1 232 respondents 366 players sustained 425 injuries, with 315 players sustaining one injury, 43 players sustaining two and 8 players sustaining three injuries, with similar patterns found for the three age groups (table 1). of the 425 injuries sustained, the u15 sustained 166 (39%) injuries, the u17 sustained 148 (35%) injuries and the u18 groups sustained 111 (26%) injuries. the injuries occurred primarily during the season (61%), with 25% occurring during the pre-season and 14% during the off-season (table 2). of the 425 injuries 24% and 46% were recurrent injuries from the previous and current seasons, respectively, while 30% of the injuries were first-time injuries. the injuries occurred primarily during 1-day matches (31%), practice (27%) and gradually (21%). the u18 groups sustained fewer injuries as a result of practices than the other two groups. the injuries were acute (50%), chronic (42%) and acute-onchronic (8%), with the injuries sustained by the u17 group more of an acute (54%) than chronic (38%) nature. the length of time that the players were unable to train or play matches due to injuries showed similar results for the three groups (table 2). table 2. injury occurrence u15 u17 u18 total % % % % time of year when injured off-season (april july) 14 13 15 14 pre-season (august september) 28 24 21 25 season (october march) 58 63 64 61 occurrence first-time 24 32 36 30 recurrent injuries previous season 25 23 24 24 current season 51 45 40 46 injury occurrence warm-up 7 11 2 7 practice 34 25 20 27 20/20 match 3 3 3 3 1-day match 27 35 29 31 gradually 18 20 25 21 other 11 6 21 11 chronicity acute 49 54 47 50 chronic 43 38 46 42 acute-on-chronic 8 8 7 8 time out of cricket 1 3 days 33 30 27 31 4 -7 days 21 18 14 18 8 14 days 11 17 20 15 15 21 days 7 9 10 8 21+ days 28 26 29 28 table 3. injury per activity and mechanism u15 u17 u18 total # % # % # % # % batting 8 13 6 10 overuse 3 7 1 11 running between wickets 2 4 1 7 spiked while running 2 4 6 bowling 47 44 45 45 run-up and delivery 61 52 40 153 over-bowling 20 9 7 36 catching, fielding and throwing 30 33 37 33 running to slide and field 7 12 6 25 running to catch/ field 12 7 11 30 impact by ball 1 5 3 9 catching ball 9 10 2 21 throwing 9 8 8 25 fitness 5 2 6 4 other sports and warm-up 22 14 15 51 training – running & gym 7 3 2 12 other 10 8 6 8 sajsm vol 24 no. 1 2012 13 of the injuries, 31% were less severe with the players not being able to practise or play for 1 3 days, while the more serious injuries (28%) resulted in the players not being able to practise or play for more than 21 days. a similar pattern was shown for the three age groups except that the injuries resulted in more of the u18 group not able to practise for 8 14 days and fewer were not able to practise or play for between 4 and 7 days. the injuries occurred primarily when bowling (45%) and fielding, including catching and running to field the ball (33%) (table 3). the u15 group showed a similar injury pattern to the total group, while the u17 players sustained more injuries while batting (13%). the u18 group sustained fewer injuries while batting, but recorded the highest percentage (37%) of injuries while fielding. the injuries were predominantly to the lower limbs (39%) and the back and trunk (33%) (table 4). the lower limb injuries were predominantly muscle (n=70) and ligament (n=43) injuries, while the back and trunk were predominantly muscle (n=78) and stress fracture (n=33) injuries. the 425 injuries were mainly muscle strains (31%), acute sprains (17%) and stress (9%) and acute (6%) fractures, with a similar pattern occurring for the three age groups (table 4). discussion the primary findings of this study are that there were some areas where the young cricketers showed similar injury patterns to the table 4. regional distribution and diagnosis of injuries u15 u17 u18 total # % # % # % # % regional distribution body region: head 4 4 5 4 eye 2 2 unconscious 1 2 3 fracture 2 1 3 6 body region: upper limbs 25 26 21 24 dislocation 5 5 2 12 joint 6 1 5 12 fracture 8 2 2 12 muscle 13 17 6 36 body region: back and trunk 31 34 35 33 stress fracture 14 9 10 33 muscle 30 28 20 78 body region: lower limbs 40 36 39 39 tendon 11 5 3 19 ligament 15 14 14 43 muscle 27 23 20 70 joint 11 4 15 \ diagnosis muscle strain 44 55 33 132 31 sprain 32 26 16 74 17 fracture 11 6 9 26 6 stress fracture 12 14 12 38 9 dislocation 5 7 1 13 3 ruptures and tendinopathy 7 10 7 24 6 periostitis 2 4 1 7 2 lacerations and haematomas 3 2 6 11 3 trigger points 5 1 6 1 other trauma 18 6 7 31 7 other 27 17 19 63 15 14 sajsm vol 24 no. 1 2012 adult cricketers, particularly with regard to the bowlers being most susceptible to injury, while there were differences in other areas. similar to the findings of adult cricketers and the previous study on schoolboy cricketers,5,7-9 the fast-bowlers were at the greatest risk of injury. back injuries to fast-bowlers are as a result of multiple factors, with abnormalities of the spine occurring at an early age, possibly aggravated by the trunk rotation in a mixed bowling technique11 and predispose the bowler to stress fractures which will be compounded through excessive bowling during the growth period when the spine is relatively immature. similarly, the most common injuries were muscle strains and injuries to the lower limbs and more injuries occurring when playing matches than when practising. when compared with the adult cricket injuries the young cricketers were at greater risk of injury to the back and trunk, with more of the injuries of a chronic nature. the greater risk of sustaining chronic overuse type of injuries to the back and trunk region in the young cricketer is a concern to all involved in cricket. while over the past number of years much effort has focused on educating coaches, administrators, parents and the young cricketer on the dangers associated with over-bowling, bowling with the mixed-actions and poor physical preparation, it would appear that there is some breakdown in the system if the young players sustain more stress fractures in the lower back than the adult cricketers. this needs to again be the focus of research to further identify factors that may predispose these young cricketers to injury. given these results and the importance of not only the number of deliveries bowled per session, but the frequency of bowling,9 coaches need to ensure that the rest guidelines are correctly enforced and that the young players have adequate rest days. differences in the nature and incidence of injuries were found for the various age groups, with the u15 and u17 groups sustaining more injuries during practices and the injuries keeping them out of cricket for 4 7 days. the u17 players showed an increase in batting injuries. the u18 players sustained fewer injuries in practices and when batting, but more injuries when bowling. also, the u18 cricketers sustained more injuries which resulted in them being out of the game for longer periods (8 14, 15 21 and 21+ days). further, the comparison of the various age groups within the junior cricketers shows differences in some other areas. while the relatively older cricketers among the youth participants were at lower risk for injuries of an acute nature while batting, they showed greater risk of injury while fielding. injuries in fielding have largely been as a result of hand and finger trauma from attempts to catch the ball, direct impacts to the body resulting from collision with the ground or other players.3,12,13 the development of one-day cricket and the increasing competitiveness of cricket at school level have resulted in fielding becoming as important a facet of the game as batting and bowling. this has resulted in the evolution of the sliding stop, where the player runs at pace after the ball and then slides on the hip and knee. as the ball is picked up in the right hand, the right foot engages the ground and the forward momentum of the slide brings the fielder upright and into a position to throw. the tactical benefits of this high-risk technique have not been adequately researched and should either be discouraged at school level or adequately coached to avoid injury.13 conclusion slight differences in the nature and incidence of injuries were found for the various age groups with some similarities to the injury patterns described in studies on adult cricketers. young fast-bowlers and fielders are at the greatest risk of injury with multi-factorial causes predisposing them to injury. the similar injury patterns to the young fast-bowlers to that of the adult fast-bowlers may be as a result of them following adult-type programmes for training, practices and matches. players, coaches, medical professionals, parents and administrators involved with the development of young cricketers need to be aware that direct extrapolation of coaching and training programmes designed for adult players may not be appropriate for young cricketers. better management of coaching and training programmes, injuries and adequate recovery time after injury would ensure that the young bowlers are better prepared for the demands of fast-bowling and would further reduce the risk of injury and re-injury in these young cricketers. references 1. orchard j, james t, alcott e. injuries in australian cricket at first class level 1995/1996 to 2000/2001. br j sports med 2002;36:270-275. 2. leary t, white j. acute injury incidence in professional county club cricketer (19851995). br j sports med 2000;34:145-147. 3. stretch ra, venter djl. cricket injuries – a longitudinal study of the nature of injuries to south african cricketers. s afr j sports med 2005;17(2):4-9. 4. mansingh a, harper l, headley s, king-mowatt j, mansingh g. injuries in west indian cricket 2003-2004. br j sports med 2006;40:119-123. 5. stretch ra. the incidence and nature of injuries in schoolboy cricketers. s afr med j 1995;85(11):1182-1184. 6. stretch ra. the incidence and nature of injuries in club and provincial cricketers. s afr med j 1993;83(5):339-341. 7. dennis rj, finch cf, farhart pj. is bowling workload a risk factor for injury to australian junior cricket fast bowlers? br j sports med 2005;39:843-846. 8. millsom nm, barnard jg, stretch ra. seasonal incidence and nature of cricket injuries among elite south african schoolboy cricketers. s afr j sports med 2007; 19(3):80-84. 9. davies r, du randt r, venter djl, stretch ra. cricket: nature and incidence of fast-bowling injuries in elite, junior level and associated risk factors. s afr j sports med 2008;20(4):115-118. 10. orchard j, newman d, stretch r, frost w, mansingh a, leipus a. methods for injury surveillance in international cricket. j sc med sport 2005;8(1):1-14. 11. elliott bc, davis jw, khangure ms, hardcastle p. disc degeneration and the young fast bowler. clin biomech 1993;8(5):227-234. 12. corrigan ab. cricket injuries. austr fam phys 1984;13(8):558-562. 13. von hagen k, roach r, summers b. the sliding stop: a technique of fielding in cricket with a potential for serious knee injury. br j sports med 2000;34:379-381. introduction a range of exercise modalities is used in the rehabilitation of individuals with chronic lower back pain (clbp), the most current being whole body vibration (wbv) training. wbv training is a novel neuromuscular mode of exercise that has recently received awareness as both a medium for improving speed-strength performance in elite athletes, but also as an alternative or complementary training modality to existing exercise programmes in most biokinetics practices and health and fitness centres. 1 according to conventional exercise programme guidelines, a wbv training programme should prove to be an ideal form of exercise for the person with clbp as it incorporates the use of large-muscle activities, increases spinal stabilisation and flexibility, while providing a basis for improving balance and neuromuscular control through the disruptions it produces in stability. the notion that wbv exploits the neuromuscular system’s ability to respond to disruptions in stability in order to stimulate and enhance muscle strength and performance has been proposed. 2 it does this by provoking an energy transfer within the body by means of vibrations that result in a stretch reflex. sedentary adults need to be persuaded to increase physical activity levels to an activity target level of moderate intensity instead of the traditional high intensity. 3 wbv training provides a means by which this requirement can be met as it provides health-related fitness benefits while reducing the non-compliance often encountered due to weather conditions, lack of motivation and work obligations. 4 this finding was substantiated in a statement that a short-term, supervised exercise protocol where the exercise scientist, health care professional or trainer has more or less direct influence and control over the intervention process, provided there is a fairly good adherence rate to the exercise programme. 5 clbp has been defined as persistent or recurrent back pain experienced by an individual for a period longer than 3 months. nociceptors in the lumbar spine and numerous psychological risk factors, such as stress, anxiety and depression could be associated with work-related clbp. 6 training on a three-dimensional vibration platform positively influences a host of psychological, physiological and health-related physical fitness parameters. 7 clbp is listed among the most common and widely experienced health-related problems. it affects up to 85% of the population at some time. 6 the prevalence and exponential increase in the occurrence of clbp has been extensively published and dates back to the initial works of hult in 1945. clbp has been reported to be the most common disability in those under the age of 45, posing the most expensive health care challenge in those between the ages of 20 and 50. 6 the world health organization report reiterated that the burden of this disability is continuing to grow and is being rapidly original research sajsm vol 23 no. 2 2011 35 interventions for chronic low back pain: whole body vibration and spinal stabilisation maryna l baard (dphil)1 jacques pietersen (phd (applied statistics))2 severius janse van rensburg (ma)1 1 department of human movement science, nelson mandela metropolitan university, port elizabeth 2 unit for statistical consultation, nelson mandela metropolitan university, port elizabeth abstract objectives. this study explored, described and compared the effects of whole body vibration (wbv) therapy and conventional spinal stabilisation exercises in persons with chronic low back pain (clbp). design. a non-randomised sampling technique was used to delineate the base of volunteers gathered by a combination of accidental and snowball sampling methods. twenty subjects were randomly assigned into either a wbv or a spinal stabilisation (ss) group. the dependent variables were perception of pain and general functionality, abdominal muscular endurance, spinal muscular endurance and hamstring flexibility. these were measured at the pre-, midand post-test assessments. during the 8-week intervention, both groups performed the same spinal stabilisation exercises 3 sessions per week, the difference being the dynamic performance of the conventional land-based ss group compared with the static, isometric performance on the vibration platform. analysis of variance (anova) determined differences between groups at the pre-, midand post-test. dependent sample t-tests were computed to determine whether the increases/decreases over time were significant within each group. cohen’s d was used to determine the practical significance of results. results. there were significant decreases in perception of pain and enhanced performance of functional activity of daily living, increases in abdominal and hamstring flexibility midway through and after the intervention period for both groups. neither of the two methods of rehabilitation was significantly superior except for spinal muscular endurance in the wbv group after the 8-week intervention. wbv could be considered as an alternative method of exercise intervention for the rehabilitation of clbp. correspondence: maryna baard department of human movement science nelson mandela metropolitan university port elizabeth south africa e-mail: maryna.baard@nmmu.ac.za fed by the globalisation and westernisation of developing countries. 8 between 50% and 80% of the population in south africa suffer from clbp at least once in their lives. 9 the multi-dimensional nature of clbp manifests as a syndrome with musculoskeletal, sensory, emotional, cognitive and behavioural components impacting on the inclination towards a lack for exercise. 6 clbp has a tendency to recur and contributes to a large portion of work absenteeism, with a loss of productivity and employee inefficiency. 10 in 2002, the cost of clbp to the economy of south africa was estimated at approximately r6 billion. 11 the american college of sports medicine (acsm) guidelines for exercise management for persons with chronic disease and disabilities postulate that the goals of exercise prescription should be to prevent the debilitation caused by inactivity and to improve exercise tolerance and muscular strength. 12 the research reported herewith sets out to explore, describe and document the effectiveness of wbv and conventional spinal stabilisation (ss) exercise intervention for individuals with clbp. methods a quasi-experimental approach using a two-group comparison, pre-, midand post-test design, was utilised to gain insight into the differences between two experimental groups over the 8-week intervention period for the four selected variables of perception of pain and functionality, abdominal muscle endurance, spinal muscle endurance and hamstring flexibility. the exercise intervention occurred 3 times a week for 8 consecutive weeks. a non-randomised sampling technique was used where subjects were selected through a combination of accidental and snowball sampling 13 and randomly placed into either the wbv (n=10) or ss group (n=11). a total of 8 males and 13 females with a mean age of 52.9 years in the wbv group and 40.3 years in the ss group gave written informed consent to participate in the study. the mean age of the total group was 46.3 years. ethical approval was given by the nelson mandela metropolitan university (nmmu) research human ethical committee. data gathering techniques prospective subjects were informed of the study by electronic mail, highlighting the rationale of the study and specifying the inclusion criteria as the presentation of symptoms of nonspecific clbp for a period of at least 3 months. all the nmmu staff were invited to participate in the study on a voluntary basis. the dependent variables included the perception of pain and functionality as measured by the revised oswestry disability questionnaire; abdominal endurance as measured by the partial curl-up test; spinal muscle endurance as measured by the roman chair back extension test; and hamstring flexibility as assessed by the sit-and-reach test. all these are wellknown standardised tests. the following procedure was employed: obtaining written consent from each participant prior to the study; gathering clinical data; applying pre-test measurement of the four dependent variables; implementing the wbv or ss exercise programme for a 4-week duration; applying mid-test measurement; implementing progression of the wbv or ss exercise programme for a further 4 weeks; and applying post-test measurement. intervention programmes both the wbv and ss groups performed the same conventional ss exercise programme as proposed by brukner and khan and others as being specific for spinal stabilisation. 6,14 the wbv programme was performed using static isometric contractions, whereas the ss programme consisted of dynamic concentric contractions. postural awareness and correct technique were of the essence during every exercise session. the principles of progression in both exercise programmes (table i) were administered under the supervision of a qualified biokineticist. statistical analysis the statistica version 9.0 computer processing package (statsoft, inc, tulsa, ok, usa) was used to analyse the data and the level of significance was set at p<0.05. for the comparisons involving the wbv and the ss group, descriptive measures of means and standard deviations were calculated and dependent t-tests were performed, while a one-way analysis of variance (anova) was applied to determine statistically significant differences between the two groups at the pre-, midand post-tests. cohen’s d-values were calculated to express the levels of practical significance. the interpretation of cohen’s d-values is as follows: d=0.20, 0.50 and 0.80 respectively indicate small, moderate and large effects in practical significance. 15 due to the relatively small sample size, non-parametric statistical analyses were performed additionally, utilising mann-whitney u tests by ranks to determine statistically significant differences between the two groups and furthermore, to ascertain whether the increases/decreases differed within the wbv and ss group. as both parametric and non-parametric statistical analyses yielded similar results and reiterate the significance of the findings, only the parametric analysis of the data will be reported. results there were no differences between the wbv and ss groups for any of the four dependent variables prior to the intervention. any significant changes could therefore be attributed to an effect of the intervention programme. table ii displays the means and standard deviations for the wbv, ss, and total group obtained throughout the 8-week intervention. perception of pain and general functionality (pp) there was a mean decrease in pp from the pre-test (30.0 arbitrary units (au)) to the mid-test (21.0 au) and then to the post-test (17.6 au) for the wbv group. a similar trend was revealed in the ss group, where a mean decrease in pp occurred from a value of 34.9 (pre test) to 26.0 au (midtest) and then to 23.4 au (posttest). 36 sajsm vol 23 no. 2 2011 table i. programme progression strategy wbv ss week time per exercise (sec) intensity (hz) total time (mins) sets reps total time (mins) 1 2 30 30 20 1 8 20 3 4 30 35 25 2 8 25 5 6 30 40 30 3 8 30 7 8 30 50 35 4 12 35 sajsm vol 23 no. 2 2011 37 statistically significant decreases pertaining to the changes in the pp-scores from the preto the mid-test (t=-4.21, p=0.002) and from the preto the post-test (t=-4.94, p=0.0007) occurred for the wbv group, as displayed in table iii. both aforementioned intragroup differences were practically significant with a large effect as indicated by cohen’s d (d=1.33 and d=1.56 respectively). table iii displays similar differences for pp in the ss group, where a statistical significance was indicated from the preto the mid-test (t=-4.43, p=0.001) and from the preto the post-test (t=-4.50, p=0.001). a large effect was found based on practical significance (d=1.34 and d=1.36 respectively). intergroup differences were examined by an anova analysis and revealed no significant differences between the wbv and ss group for perception of pain and general functionality at any one of the testing stages. abdominal muscular endurance (ms) results obtained for ms as measured by the modified sit-up test revealed a mean increase of eight repetitions from the preto the post-test in the wbv group while the mean score of the ss group increased by four repetitions. the ms scores of the ss group increased from the preto the mid-test (5 repetitions, mean score of 27.8 34.6 repetitions), but decreased slightly from the midto the post-test (34.6 33.7 repetitions). intra-group differences in ms of the wbv group were statistically significant, as indicated in table iii where the values increased from the preto the mid-test (t=3.40, p=0.01) and from the preto the posttest (t=2.70, p=0.03). both aforementioned increases were practically significant with a large effect as indicated by cohen’s d (d=1.29 and d=0.91 respectively). table iii displays similar increases for ms in the ss group. here the difference only approached significance from the preto the mid-test (t=2.24, p=0.059), yet the difference was statistically significant from the pre-test to the post-test (t=2.56, p=0.03). practical significance of a moderate effect was achieved by cohen’s d (d=0.79) for the preto mid-test, while practical significance with a large effect was indicated from the preto post-test (d=0.91). no significant intergroup differences were found between the wbv and ss group for abdominal muscle endurance at any one of the testing stages. spinal muscular endurance (be) results obtained for spinal muscle endurance as measured by the back extension (be) test revealed an increase in be from a mean pre-test value of 20.6 repetitions to a mid-test mean value of 23.3 repetitions and then to a post-test mean value of 24.9 repetitions for the wbv group. the be for the ss group increased from a mean score of 15.5 to 15.8 repetitions and then to 18.5 repetitions. there was a statistically significant increase for be from the preto posttest in the wbv group (t=2.62, p=0.03) with a large effect for practical significance of cohen’s d (d=0.87) as tabulated in table iii. however, the increase in be for the ss group approached significance for the midto post-test result only (t=2.25, p=0.058) where a practical significance with a large effect (d=0.80) was designated, as shown in table iii. once again the wbv and ss group revealed no significant intergroup differences for spinal muscle endurance at any one of the testing stages. hamstring flexibility (sr) results for sr as measured by the sit-and-reach test indicated that the wbv group achieved an increase from a mean value of 247.1 table ii. means and standard deviations for the groups group measure wbv (n=10) mean ± sd ss (n=11) mean ± sd total (n=21) mean ± sd (repetitions) ms1 (pre) 36.4 ± 20.9 27.9 ± 25.2 31.8 ± 22.9 ms2 (mid) 39.3 ± 19.6 34.6 ± 24.5 36.9 ± 21.6 ms3 (post) 41.5 ± 22.6 33.8 ± 25.8 37.6 ± 23.8 (repetitions) be1 (pre) 20.7 ± 09.8 15.6 ± 08.5 18.4 ± 09.3 be2 (mid) 23.2 ± 12.8 15.9 ± 08.2 19.9 ± 11.3 be3 (post) 24.9 ± 12.8 18.5 ± 08.9 22.0 ± 11.4 (mm) sr1 (pre) 247.1 ± 88.5 208.2 ± 89.5 224.5 ± 88.8 sr2 (mid) 271.3 ± 85.2 230.0 ± 90.1 247.3 ± 88.1 sr3 (post) 276.3 ± 99.4 245.5 ± 91.1 258.4 ± 93.2 (score) pp1 (pre) 30.0 ± 08.7 34.9 ± 16.8 32.5 ± 13.5 pp2 (mid) 21.0 ± 10.8 26.0 ± 13.7 23.6 ± 12.3 pp3 (post) 17.6 ± 13.2 23.5 ± 14.9 20.6 ± 14.1 wbv = whole body vibration; ss = spinal stabilisation exercises; ms = modified sit-ups; be = back extension; sr = sit and reach; pp = perception of pain and general functionality. mm (pre-test) to 271.2 mm (mid-test) and then to 276.2 mm (posttest), while the ss obtained an increase from 208.1 to 230.0 mm and then to 245.4 mm over the same 8-week intervention period. a statistically significant increase in sr from the preto mid -test was revealed for the wbv group (t=4.70, p=0.002) with a large effect based on practical significance (d=1.66) as seen in table iii. furthermore, from the preto post-test a statistical significant increase was attained by the wbv group (t=3.29, p=0.01) with a large effect in practical significance (d=1.17). table iii reveals a statistically significant increase in be for the ss group with practical significant large effects for all three assessments, namely: from the preto mid-test (t=2.74, p=0.02, d=0.83), the midto posttest (t=3.13, d=0.01, d=0.95), and the preto post-test (t=3.86, p=0.003, d=1.17). the ss group, however, initially had a lower score and therefore had more scope for increasing hamstring flexibility. no significant intergroup differences were indicated between the wbv and ss group for hamstring flexibility at any one of the testing stages. discussion the results of this study indicated that both the wbv and ss exercises relieved pain and improved pain-related limitations in the performance of activities of daily living for individuals with clbp. the mechanism of proprioceptive feedback and potentiation of inhibition of pain whereby an individual’s pain threshold increased, could have contributed to both experimental groups’ decrease in the perception of pain and enhanced general functionality. 6 this finding that vibration therapy alleviated perception of pain and daily functionality is in contrast to literature where industrial and non-industrial circumstances have been regarded as predisposing risk factors in the aetiology of clbp. however, differentiation between industrial and therapeutic wbv therapy on variables have been made such as the method of the vibratory application, the individual’s posture, the frequency of the application and the duration of exposure to the vibration, as well as the resulting fatigue. 7 the findings regarding abdominal muscle endurance correspond with unpublished research 16 and published work 17 where the study revealed an improvement in abdominal endurance after a 12-week wbv therapy programme in previously sedentary individuals. the latter reported that vibratory waves irritated the primary endings of the muscle spindle that activated a larger fraction of the motor neuron pool and recruited previously inactive motor units into contraction. this resulted in a more efficient use of the force production potential of the muscle groups involved. this mechanism of motor neuron pool activation was further reinforced during wbv by the recruitment of previously inactive motor neurons, together with their activity synchronisation, and increased discharge of the neural drive, which led to greater improvements in neuromotor control during voluntary muscle contraction as evaluated in the modified sit-up analyses. could aforementioned theory substantiate the finding of a significant maintenance of increased abdominal muscle endurance throughout the 8-week intervention for the wbv group, while the ss group decreased in ms after the mid-test assessment? increased spinal muscular endurance after completing a 12-week wbv exercise programme has been reported. 7 the findings of the present study support the findings of the aforementioned research. the rationale stated for the increased abdominal musculature endurance also applies to results obtained for this variable, namely that the muscle spindles activated a larger fraction of the motor neuron pool and recruited previously inactive motor units into contraction, thus resulting in a more efficient use of the force production potential of the muscle groups involved. 17 the use of hamstring flexibility exercises during the 8-week intervention period had a positive effect on the range of motion around the posterior compartment of the hip joint and pelvis for both wbv and ss experimental groups. however, the ss group in comparison increased more significantly in hamstring flexibility in the midtest and could be ascribed to the lower score obtained for sr at the onset of the study. it could be reasoned that subjects in the ss group had a greater scope of improving the hamstring flexibility due to the exercise stimulus. these findings support the results reported of a significant increase in hamstring flexibility after a 12-week intervention period utilising static stretching to enhance hamstring flexibility. 18 the improvement in hamstring flexibility in both experimental groups could be explained within a physiological paradigm according to the involvement of two possible mechanisms. firstly, the enhanced local blood flow through the muscles generated additional heat, thereby enhancing muscle elasticity and facilitating an increase in range of motion in the hamstring muscles. 19,20 the second mechanism proposed is neurophysiological in nature as the vibration training elicited a tonic vibration reflex that activated the muscle spindles and led to the advancement of the stretch-reflex loop. based on the findings for all the selected relevant dependent variables, the proposal can be made that wbv be considered by the health care professional as a means to decrease the perception of pain and increase the selected health-related variables in individuals with clbp. 38 sajsm vol 23 no. 2 2011 table iii. difference between three testing sessions for each measure within each group wbv gr (n=10) ss gr (n=11) measure md±sd t p d md±sd t p d units: score pp: pre mid -9±7 4.43 0.001 1.34 -9±7 -4.43 0.001 1.34 pp: mid post -3±4 2.35 0.040 0.40 -3±4 -2.35 0.040 0.71 pp: pre post -12±8 4.94 0.010 1.56 -11±8 -4.50 0.001 1.36 units: repetitions ms: pre mid 5±4 3.40 0.010 1.29 7±9 2.24 0.050 0.79 ms: mid post 2±6 1.04 0.320 0.37 -1±5 -0.50 0.620 0.18 ms: pre post 8±8 2.70 0.030 1.02 6±6 2.56 0.030 0.91 units: repetitions be: pre mid 4±10 1.20 0.260 0.40 1±4 0.50 0.620 0.19 be: mid post 2±6 0.97 0.030 0.87 6±7 2.62 0.350 0.87 be: pre post 6±7 2.62 0.030 0.87 6±7 2.62 0.030 0.87 units: mm sr: pre mid 24±15 4.70 0.002 1.66 22±26 2.74 0.020 0.83 sr: mid post 25±19 0.76 0.460 0.27 15±16 3.13 0.010 0.95 sr: pre post 29±25 3.29 0.010 1.17 37±32 3.86 0.003 1.17 wbv = whole body vibration; ss = spinal stabilisation exercises; ms = modified sit-ups; be = back extension; sr = sit and reach; pp = perception of pain and general functionality. sajsm vol 23 no. 2 2011 39 conclusion clbp is internationally a major concern in the field of rehabilitation due to the high incidence rates and the high rate of re-occurrence. individuals suffering from clbp often experience a cycle of pain, disuse, further pain and less usage. they become debilitated and suffer from a decrease in strength, endurance and flexibility. although a myriad range of exercise techniques are used in the rehabilitation of individuals with clbp, health care professionals realise the essence of postural awareness, strengthening the core abdominal and lumbar stabilising musculature and re-education as composites of any intervention programme. although the study was conducted on a relatively small sample group over a period of 8 weeks only, it provides useful information that indicates alternative options for the treatment of clbp. both wbv and ss showed improvements in the dependent variables of pain perception and general functionality, abdominal and spinal muscular endurance and hamstring flexibility after participating in the 8-week wbv and ss intervention programmes. the findings indicated that both wbv and conventional ss were effective exercise regimes for individuals with clbp. neither of the two methods of intervention was superior in producing more significant results and supported previous studies in the literature reporting positive results. wbv therapy appears to be a safe, rehabilitative exercise modality that improves lower back and hamstring flexibility, increases relative back strength and increases abdominal muscular endurance. however, further research is needed to replicate these results on the long-term effects of wbv in clbp. future research is required to ascertain what the re-occurrence rate is for individuals with clbp who followed vibration therapy as opposed to conventional modes of intervention programme prescription. vibration therapy in the form of wbv could be considered as an alternative method of exercise intervention for the rehabilitation of clbp, if designed, presented and supervised by a specialist health professional. references 1. delecluse c, roelants m, diels r, konickx e, verschueren s. effects of whole body vibration training on muscle strength and sprint performance in sprint-trained athletes. int j sports med 2005;26:662-668. 2. ribot-ciscar e, rossi-durand c, roll j-p. muscle spindle activity following muscle tendon vibration in man. neurosci l 1998;258:147-150. 3. swain dp. moderate or vigorous intensity exercise: what should we prescribe? acsm health fitness j 2007;10(5):7-11. 4. mancuso ca, sayles w, robbins l, et al. barriers and facilitators to healthy physical activity in asthma patients. j asthma 2006;43:137-143. 5. emtner m, hedin a. adherence to and effects of physical activity on health in adults with asthma. adv physiother 2005;7:123-134. 6. brukner p, khan k. clinical sports medicine, 3rd ed. sydney (australia): mcgraw-hill, 2007:352-356. 7. rittweger j, karsten j, kautzsch k, reeg p, felsenberg d. treatment of chronic lower back pain with lumbar extension and whole-body vibration exercise. spine 2002;27(17):1829-1834. 8. who (world health organization). preventing chronic diseases: a vital investment. geneva. fifty-seventh world health assembly (wha 57.17) held on 24 may 2004 agenda item 12.6 for discussion on ‘global strategy on diet, physical activity and health’. 2004. 9. van vuuren b, van heerden h, becker pj, zinzen e, meeusen r. fearavoidance beliefs and pain coping strategies in rehabilitation to lower back problems in a south african steel industry. eur j pain 2006;10(1):233239. 10. who (world health organization). reducing risks, promoting healthy life. the world health report. geneva. fifty-seventh world health assembly (wha 57.17) held on 24 may 2004. agenda item 12.6 for discussion on ‘global strategy on diet, physical activity and health’, 2004. 11. belot sr. speech by the mec of health, mr st belot, at the opening of 2005 back week, university of the free state, bloemfontein, rsa. http:// www.fs.gov.za/speeches/2005/health/mec’s%20speech%20back%20 week%20120septb.doc, 2005. 12. durstine jl, moore ge. acsm’s exercise management for persons with chronic diseases and disabilities, 3rd ed. champaign, il: human kinetics, 2003;217-220. 13. de vos as, strydom h, fouché cb, delport csl. research at grass roots: for the social sciences and human service professionals, 3rd ed. pretoria: van schaik, 2005. 14. arokoski jp, valta t, airaksinen o, kankaanpaa m. back and abdominal muscle function during stabilization exercises. arch phys med rehabil 2001;82(3):1089-1098. 15. steyn hs. (2009). manual for the determination of effect size indices and practical significance. http://www.puk.ac.za/opencms/export/puk/ html/fakulteite/natuur/skd/handleiding_e.html 2009 (retrieved 27 october 2010). 16. kholvadia a, baard ml. whole body vibration therapy as a conditioning programme for health promotion. unpublished master’s thesis. port elizabeth: nelson mandela metropolitan university (nmmu), dept of human movement science, 2008. 17. ekelund lq, haskell wl, johnson jl, whaley fs, criqui mh, sheps ds. physical fitness as a predictor of cardiovascular mortality in asymptomatic north american men. nej m 1988;319:1379-1384. 18. chrier i, gossal k. 2000. myths and truths of strengthening: individualized recommendations for healthy muscles. psm 2000;28(8):57-63. 19. hoeger wk, hoeger sa. lifetime physical fitness and wellness: a personalized program, 11th ed. belmont, ca: wadsworth, 2011:261-262. 20. earle rw, baechle tr. national strength and conditioning association’s essentials of personal training. champaign, il: human kinetics, 2004:268-272. original research 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license pain and physical activity levels among rheumatoid arthritis patients between the ages of 18 to 50 years in south africa rm wilkinson, bbio; l smith, mphil; s ferreira, mphil department of sport and movement studies in the faculty of health sciences, university of johannesburg, doornfontein campus, p.o. box 524, auckland park, 2006, johannesburg, south africa corresponding author: rm wilkinson (rebecca@wrc.co.za) arthritis is a musculoskeletal disorder which holds the potential of being disabling. [1] arthritis affects people worldwide, with disability and functional limitations being characteristics of the disorder. [1] rheumatoid arthritis is characterised by systemic inflammation, which can result in joint damage, disability and functional limitations. [1] diseasemodifying anti-rheumatic drugs, anti-inflammatories and analgesics are the types of medications commonly prescribed for the management of ra. [1] however, when the systemic inflammation in ra is poorly controlled and patients follow an unhealthy lifestyle, they are at risk for developing various comorbidities. [1, 2, 3] the incidence of cardiovascular events in those diagnosed with ra is estimated to be double that compared to the general population, with cardiovascular disease (cvd) typically developing at an earlier age in this population. [2] obesity further increases the comorbidity risk in those with ra, with obesity and poor body composition related to ra, pharmacology and to physical inactivity. [1, 3] it has been suggested that ra patients are less active due to joint manifestations relating to the disease as well as other ‘general’ barriers, yet regular physical activity is an effective treatment and management tool for ra. [2, 3] currently, exercise and the broad range of treatment options for ra are trumped by medication as the favoured modality; however, when considering longevity, interventions such as exercise become essential. [2, 4] physical activity as therapeutic management has been proven to possess a range of benefits, including the improvement of general health and functional ability, as well as the reduction of associated disability. [2] furthermore, physical activity is suitable for most individuals and can be used in conjunction with prescribed medications, which may allow for a reduced dosage while simultaneously benefitting general health status. [1, 2] however, various international research studies demonstrate that only a small percentage of ra patients are physically active. [1, 5, 6] several countries have conducted research on physical activity participation among ra patients, but with the unpredictable and changing landscape in south africa, as well as its economic development, there is a need to assess the current physical activity levels in a local context, and to identify barriers to physical activity participation. [1, 5, 6] therefore, the purpose of this study was to determine pain and activity levels at work, while travelling or during leisure activities of ra patients in a south african context. the objectives of the study were: (1) determine whether most physical activity is completed during work, travel or recreation; (2) quantify the amount of time spent sedentary on a normal day; (3) determine the correlation between the pain, physical activity level, ambulation and personal grooming; (4) determine self-reported physical activity levels, overall energy levels, strength and endurance; and (5) determine patients’ perceptions on injury, risk and safety of exercise. methods study design this study was cross-sectional in design and quantitative data were collected and analysed. to achieve the aim of the study, a combination of two questionnaires were utilised: the global physical activity questionnaire (gpaq) and the pain background: little epidemiological research on rheumatoid arthritis (ra) has been done in africa, suggesting that it is an uncommon illness. in rural south africa, ra has an overall prevalence of 0.07% and a prevalence of 2.5% in urban areas; therefore, it is not as uncommon as perceived by the lack of research. patient-centred programmes to improve physical function have been lacking and, as a result, the prior assumption was that physical activity should be avoided. objectives: to determine pain and physical activity levels among ra patients between the ages of 18 to 50 years in south africa. methods: a combination of two questionnaires were used, namely, the global physical activity questionnaire (2002) and the pain outcomes questionnaire (2003). the collated questionnaires were distributed by rheumatologists and on social media platforms to ra patients between the ages of 18 to 50 years old living in south africa. this study had a sample size of 105 participants, with participation occurring through the online google forms platform. results: one hundred and five participants with ra were recruited with an average age of 38±9 years. most of the participants were females (93.3%). seventy-two percent of the sample was classified as physically active, where work, leisure and travel activities were considered. no significant correlation between pain and physical activity was evident (r=0.10; p=0.311). results showed significant correlations between pain and personal grooming (r=0.30; p=0.002), pain and ambulation (r=0.60; p=0.000), and pain and stair climbing (r=0.60; p=0.000). conclusion: physical activity has proven to have multiple benefits for those suffering with ra. in this south african sample of ra patients, the majority were classified as physically active, and pain did not affect the activity levels of the involved participants. this study opens further research questions regarding ra prevalence in south africa, and the type and intensity of physical activity that would be beneficial for ra. keywords: inflammatory disease, exercise, physical limitations s afr j sports med 2022;34:1-8. doi: 10.17159/2078-516x/2022/v34i1a11555 mailto:rebecca@wrc.co.za http://dx.doi.org/10.17159/2078-516x/2022/v34i1a11555 https://orcid.org/0000-0002-1446-3458 https://orcid.org/0000-0002-8562-5004 https://orcid.org/0000-0002-9203-8537 original research sajsm vol. 34 no.1 2022 2 outcomes questionnaire (poq). the collated questionnaires were made available on the google forms platform, allowing participants to access and complete them online. selection and description of participants various rheumatologists were contacted to distribute the google forms link to the patients in their practices who met the inclusion criteria of this study. additionally, the link was published to ra support groups and social media platforms by the researcher. a sample of 105 participants complying with the inclusion criteria were recruited by means of purposive sampling. participants were diverse in terms of backgrounds, provinces and treating rheumatologists. inclusion criteria  clinically diagnosed with ra.  between the ages of 18 and 50 years at the time of data collection. the minimum age of 18 years was established to allow the participant to consent independently to participation in the research study. the exclusion of individuals older than 50 years of age was determined due to the relationship between increased age and comorbidities, which could impact physical activity levels and the performance of daily activities.  residents in south africa at the time of data collection.  male or female.  internet access to complete the questionnaire. ethical considerations all participants were informed about the purpose of the research by means of an information letter and were required to provide consent before data collection commenced. the study participants were aware that participation was voluntary and that withdrawal from the study could only take place before submission of the questionnaire. every precaution was taken to protect the privacy of the participants and confidentiality of their personal information was ensured. this study was approved by the institutional research ethics committee (rec-171-2019). questionnaires as mentioned, two combined questionnaires were used to gather subjective data relating to the pain and physical activity levels of the participants. although the questionnaires included demographic questions, no identifying data was gathered and therefore, participation was anonymous. the questions in the gpaq were centred on the participants’ activity levels during work, travel and leisure. the poq was adapted by removing questions that were not relevant to the aims and objectives of this study. therefore, the poq was centred on the participants’ overall pain levels, as well as how pain affects their daily activities. statistical analysis the data collected were quantitative in nature. statistical analysis was completed using the statistical package for social science (spss) version 26.0 and included percentages, means, standard deviations and correlations. the kolmogorovsmirnov test was used to assess the normality of the distribution of the data. to determine the correlations between the variables of interest, the pearson product-moment correlation coefficient was computed because normality of the data was established. a calculation of statistical significance was done yielding 5% as the level of significance. results demographics a total of 105 ra patients took part in the present study, with the demographic results demonstrated in table 1. the mean age of the participants was 38±9, and only 7 participants were of the male gender. the mean age of ra diagnosis was 32 years. eighteen of the 105 participants were not currently seeking treatment for their condition. majority of the participants resided in the gauteng province, with only 36 participants residing elsewhere. global physical activity questionnaire many participants had declared that they were physically active across more than one of the categories presented in table 2. based on the general physical activity guidelines, 29 participants (27.6%) were classified as physically inactive, while 76 participants (72.4%) were classified as physically active. [3] both vigorous and moderate intensity activity was performed at work by 10 (9.5%) and 43 (41%) of the participants table 1. demographic results of the sample (n=105) frequency percentage (%) mean ± sd age (years) 18-29 22 20.9 38 ± 9 30-39 30 28.6 40-50 53 50.5 gender females 98 93.3 males 7 6.7 age of diagnosis (years) 0-17 18 17.1 32 ± 11 18-29 26 24.8 30-40 30 28.6 40-50 31 29.5 seeking treatment yes 87 82.9 no 18 17.1 province of residence gauteng 69 65.7 kwazulunatal 11 10.5 free state 4 3.8 limpopo 1 0.95 northern cape 2 1.9 western cape 15 14.3 north west 2 1.9 mpumalanga 1 0.95 original research 3 sajsm vol. 34 no.1 2022 respectively. the mean time spent being physically active at work at a vigorous intensity was 229 minutes with a mean of four and a half days, while the mean amount of time spent doing moderate intensity activity at work was 175 minutes with a mean of four days. the number of participants in the different categories of physical activity is shown in fig. 1. sixteen participants (15%) performed no physical activity. leisure activity had the highest number of participants and travel the least, with 27 (26%) and six (6%) respectively. nine participants (9%) performed physical activity in all three categories. the participants were required to select the amount of time they spend seated or reclining on a typical day. the categories of choice were 1-2 hours, 3-4 hours, 56 hours and >7 hours, with 12 (11.43%), 24 (22.86%), 42 (40%) and 27 (25.71%) selected respectively. pain outcomes questionnaire a 10-point likert scale was used to respond to the poq questions, results of which can be seen in table 3. out of 10, 5.8 was the mean pain level selected. the interference of their pain with daily activities yielded the following means: walking 5.3, carrying objects 5.9, stair climbing 5.5, and personal grooming 2.7. the participants’ mean rating of their personal physical activity, overall energy and strength and endurance was 4.9, 4.2 and 4.7 respectively. for depressive feelings on the day of the questionnaire, the mean response was 4.5. with regards to the fear of re-injuring themselves and exercise safety, the mean scores were 6.8 and 6.1 respectively, noting that none of the participants selected a score of zero for the last two questions. categories of physical activities and associated mean pain level in table 4, when looking at the average pain levels reported for each of the categories of physical activity, the participants performing activity in both work and travel reported the highest mean pain levels (7.4±1.4 au), followed by the participants performing no physical activity (6.4±2.3 au). the lowest mean pain level reported was by the participants performing physical activity in the travel only category (3.7±2.8 au). correlations table 5 demonstrates the correlations of interest for the present study. the correlation between pain and total physical activity performed was r=0.10 for pearson’s product moment correlations, demonstrating a slight effect of pain on physical activity participation. [7] the correlation between pain and the affected ability to walk was significant (r=0.60, p=0.0001) with a table 2. global physical activity questionnaire data (n=105) category response frequency percentage (%) number of days time (minutes/day) work – vigorous intensity yes 10 9.5 4.5 ± 1.3 229 ± 146 no 72 68.6 unemployed 15 14.3 student 8 7.6 work moderate intensity yes 43 41.0 4.0 ± 1.9 175 ± 138 no 39 37.1 not applicable 23 21.9 travel walking or cycling yes 33 31.4 4.7 ± 2.0 111 ± 157 no 72 68.6 leisure, sports and recreation vigorous intensity yes 37 35.2 3.1 ± 1.4 60 ± 26 no 68 64.8 leisure, sports and recreation moderate intensity yes 56 53.3 2.8 ± 1.4 57 ± 38 no 49 46.7 data expressed as mean ± sd unless indicated otherwise. fig. 1. categories of physical activity completed by the participants (n=105) n u m b e r o f p a r ti c ip a n ts original research sajsm vol. 34 no.1 2022 4 moderate positive correlation. [7] another moderate positive correlation of r=0.60 was found between pain and the affected ability to climb stairs, also demonstrating a significance of p=0.0001. [7] pain and the affected ability to manage personal grooming yielded a fair positive correlation of r=0.30, with significance of p=0.002. [7] discussion the aim of this paper was to determine the relationships between pain and physical activity levels in a south african sample of ra patients between the ages of 18 and 50 years. during the study, the amount of physical activity performed during work, travel or leisure was determined and the amount of time patients are sedentary on a normal day was quantified. in addition, the correlation between pain, physical activity level, personal grooming, ambulation, and stair climbing was determined by means of a self-reported questionnaire. two questionnaires were collated to achieve the above, namely the global physical activity questionnaire and the pain outcomes questionnaire. demographics ra is said to affect 1% of the general population; therefore, it is expected that the sample size in this study would be smaller in comparison to studies centred around more prevalent conditions. [8] the prevalence of ra in south africa ranges from 0.07% to 2.5% in rural and urban areas respectively. [9] the unequal distribution of gender in the study is consistent with numerous studies stating a higher prevalence among the female population. [1, 10] rheumatoid arthritis has been shown to be four to five times more likely in females compared to males below the age of 50 years, but in african countries, the ratio is as large as 6:1 which is similar to that found in the sample in the present study. [10] the prevalence ratio tends to decrease in populations older than 60 years, where the female to male ratio is approximately 2:1. [10] in the present study, the mean age of diagnosis was 32 years, and 41.9% of the sample table 3. pain outcomes questionnaire data (n=105) question mean ± sd max value selected min value selected average pain levels during the last week (0=no pain at all; 10=worst possible pain) 5.8 ± 2.3 10 0 does your pain interfere with your ability to walk (0= not at all; 10= all the time) 5.3 ± 3.1 10 0 does your pain interfere with your ability to carry / handle everyday objects such as bag of groceries or books (0= not at all; 10= all the time) 5.9 ± 2.8 10 0 does your pain interfere with your ability to climb stairs (0= not at all; 10= all the time) 5.5 ± 3.4 10 0 does your pain require you to use a walker, cane, wheelchair or other device (0= not at all; 10= all the time) 0.9 ± 2.2 10 0 does your pain interfere with your ability to manage your personal grooming (combing hair, brushing teeth, etc) (0= not at all; 10= all the time) 2.7 ± 2.8 10 0 how would you rate your physical activity (0= significant limitations with basic activity; 10= can perform vigorous activity without limitations) 4.9 ± 1.9 10 0 how would you rate your overall energy (0= totally worn out; 10= most energy ever) 4.2 ± 1.9 9 1 how would you rate your strength and endurance today (0= very poor; 10= very high) 4.7 ± 2.0 10 1 how would you rate your feelings of depression today (0= not at all depressed; 10= extremely depressed) 4.5 ± 2.5 10 0 how much do you worry about re-injuring yourself if you are more active (0= not at all; 10= all the time) 6.8 ± 2.8 10 1 how safe do you think it is for you to exercise (0= not safe at all; 10= extremely safe) 6.1 ± 2.1 10 1 table 4. the different categories of physical activity and the associated average pain levels category of exercise participation participants (%) pain (au) completely sedentary 15 6.4 ± 2.3 leisure 26 5.2 ± 2.1 work 11 6.3 ± 2.9 travel 6 3.7 ± 2.8 leisure and work 16 5.8 ± 2.5 work and travel 8 7.4 ± 1.4 leisure and travel 9 5.3 ± 1.8 leisure, travel and work 9 6.3 ± 1.2 data expressed as mean ± sd unless indicated otherwise. au, arbitrary units table 5. pearson product moment correlations between variables of interest variables r p-value pain level and total activity time by each participant 0.10 0.31 pain level and the affected ability to walk 0.60 0.0001* pain level and the affected ability to climb stairs 0.60 0.0001* pain level and the affected ability to manage personal grooming 0.30 0.002* * indicates significance (p<0.05). original research 5 sajsm vol. 34 no.1 2022 declared being diagnosed before 30 years of age. research has reported the typical onset age for ra to be between 40 to 50 years; therefore, the mean of the present study is younger than this age. [1] a possible explanation for this is the age limitation for participation in the study, which was 18 to 50 years, and in addition, african samples have reported an average age of onset of 27 years. [11] the large distribution of participants located in the gauteng province is attributed to gauteng having the greatest population density, coupled with the highest internet connectivity in south africa. [12] global physical activity questionnaire (gpaq) when participants were asked about their participation in physical activity, results showed that 15.24% of the sample was sedentary and 72.4% were classified as physically active. results also indicate that although only 15.24% of the sample declared that they were not partaking in any physical activity, a further 12.36% of the participants who were physically active were not performing sufficient levels of physical activity. the classification of sedentariness was determined in consultation with the american college of sports medicine (acsm) guidelines on physical activity for psychological and physiological health benefits. [3] to be classed as physically active one must participate in 150 minutes of moderate intensity activity or 75 minutes of vigorous intensity activity, per week. [3] the results in the present study contrast with previous studies among american and european ra patients, which made use of standardised fitness tests to measure aerobic fitness, physical strength, agility, and endurance, as well as self-report questionnaires to determine physical activity participation, where 69% and 68% of participants, respectively, were classified as inactive. [1, 2] in addition, a study making use of the quest-ra (a quantitative clinical assessment of patients with rheumatoid arthritis seen in standard rheumatology care in 15 countries) was conducted on ra patients across 21 countries, which reported that only 13.8% of the participants were partaking in physical exercise three or more days per week. [6] there is a notable difference between these international studies and the present study, which could be attributed to the international studies collecting responses on exercise participation in isolation, in comparison to the present study which collected responses on physical activity during work, travel and leisure. [3] in 2020, a study conducted across 104 countries revealed that work, household, and travel activity measured with the gpaq are important considerations when evaluating overall physical activity levels, especially in countries that continue to develop economically. [13] these are alternative forms of physical activity that are easily accessible and affordable to individuals who are susceptible to decreased physical activity due to societal and economic barriers. [13] both vigorous and moderate intensity activity was performed by 37% of the participants in the present study. although low impact and moderate intensity activity has been encouraged in this population for safety reasons, there is currently no direct evidence against vigorous intensity exercise participation in those with ra. [3] a pilot study among older ra patients reported that high-intensity interval training performed at levels exceeding that of the current health guidelines (of 150 minutes of moderate intensity activity or 75 minutes of vigorous intensity activity, per week, according to the acsm) is associated with numerous benefits in this population. [14] increased cardiorespiratory fitness and reduced disease activity were among many of the benefits experienced after ten weeks of vigorous intensity activity. [14] evidence also exists that prolonged moderate to vigorous intensity activity reduces inflammatory markers, having a similar effect to medication on the treatment of ra, slows down disease progression, and reduces pain and fatigue. [14] in this study, 14.3% of the sample were unemployed. due to the associated disability and cost incurred through treatment, ra affects patients economically. [4] unemployment is a concern as it impacts the patient’s ability to afford the treatment aiding in the management of their condition. [4] of those who participated, 65.71% spent five or more hours sitting or reclining on a typical day. sedentary behaviour possesses serious health consequences by increasing the risk of both developing and progressing diseases while simultaneously affecting general health. [2, 15] in 13 international studies it was found that those who performed no physical activity and reclined for more than eight hours a day had a similar mortality risk to obese individuals and smokers. [15] it is important to note that prolonged sitting is a risk factor for allcause mortality and may result in a viscous cycle between disease progression and health, therefore; it is essential for health interventions to minimise the amount of time spent seated. [2, 15] pain outcomes questionnaire (poq) the main complaint from ra patients is pain, which is a result of joint inflammation. [1, 10] the mean pain level of the sample in this study was 5.8/10, with 7/20 being the most commonly selected response. a heightened pain response is seen in those with ra, as pain is a major symptom of the condition and generally impacts the modality of treatment. [16] by making use of a 0-to-10-point scale to assess pain, this study only focused on the intensity of pain. other aspects of pain also need to be considered to determine the total impact of pain on the individual. [16] difficulty with daily tasks and reduced quality of life are frequently seen in those with chronic musculoskeletal conditions, which consequently catalyses institutionalisation, dependency, and increased healthcare needs. [4] the responses for this study demonstrated a mean score of 5.3/10, 5.9/10 and 5.5/10 for difficulty walking, carrying everyday objects and climbing stairs, respectively. considering the young and middle ages of the participants in this sample, this is concerning as there are apparent issues with their ability to perform activities of daily living which may intensify with increased age and time should the disease progress. [1] although physical activity offers therapeutic management for ra, there is a consistent concern that exercise participation can or will exacerbate symptoms and joint damage. [8, 17] of the rheumatologists who participated in the iverson et al study, 83% believed that exercise was an effective approach to managing symptoms of ra, yet none deemed themselves original research sajsm vol. 34 no.1 2022 6 knowledgeable enough on exercise participation to correctly advise their patients. [17] when asked to rate their physical activity levels, the most commonly selected response by the participants was 5/10, which is logical considering that 72.4% of the sample were achieving the recommended amount of physical activity in a week. [3] notably, only 19% of the sample selected a seven or more out of 10 for their physical activity. physically active individuals appear to have a greater capability to overcome the associated barriers of participating in physical activity. [8] for patients who are not physically active, rheumatologists advocated a “mind shift” and proposed that positive mental health is achieved prior to the initiation of a physical activity programme. [17] the mean energy levels selected by the participants was 4.2/10, noting that no participant rated their energy level as 10/10. according to the literature, one of the reported symptoms of ra is mental and physical fatigue, hence this finding was not completely unexpected. [1, 8] the mean rating of experiencing symptoms of depression was 4.5/10, with the most commonly selected answer being four. in a 2019 study of ra patients, 55% of the participants reported having mild or worse symptoms of depression and 22% experienced moderate or worse symptoms of depression. [18] of those participants, only 12% were seeking treatment for depression. [18] as mentioned above, the concern and fear of worsening the condition or causing injury when participating in physical activity is one of the most frequently mentioned barriers to physical activity participation in this population. [8, 17] this study enquired about the fear of re-injury with physical activity participation and the mean response was 6.8/10, with the most common response being eight. regarding feelings around the safety of exercise for ra, 80% of the sample selected five or higher out of 10 (with 10 being ‘extremely safe’). of the research studies that have been completed on the safety of physical activity and exercise participation in the ra population, little data has demonstrated that it negatively impacts on the condition. [2, 5, 8] rather, extensive research has advocated for physical activity participation due to its benefits for ra patients. [2, 5, 8] categories of physical activity and mean pain levels additional analysis of the data examined the mean pain levels reported for the different physical activity categories. looking at the different categories, the highest average pain level experienced was in the category of work and travel activity (7.4 au). the mode and intensity of physical activity needs to suite the individual in terms of condition and abilities, as well as being ‘balanced’, with sufficient recovery time. thus, one’s work-related physical activity demands may not be entirely appropriate in this regard. [4] the sedentary participants reported the second highest average pain level (6.4 au), which is consistent with previous literature, as physical activity plays a role in reducing and aiding pain levels experienced in those with ra. [2, 8, 17] the travel only category (involving walking and/or cycling) had the lowest pain level, with an average of 3.7 au. active travel activities, such as walking and cycling, are seen in both highand low-income countries, as beneficial for general health, and can contribute to one’s overall physical activity level. [13] correlations an essential component of ra treatment is the management of pain experienced, with the prospect that effective pain management may promote compliance to therapy as well as fostering physical activity participation. [16] in the present study, it was established that pain had a slight positive effect on the physical activity participation in these participants. [7] including travel, work and leisure activities could explain this unexpected result, as should one experience pain, participants may opt to avoid performing leisurely physical activity; however, should their work or travel require physical activity, they may have no option but to still participate in the activity to complete their tasks. chronic pain can substantially affect an individual’s ability to perform daily tasks. [19] the correlation between pain and affected ability to walk demonstrated that pain does impact the ability to walk through a moderate positive correlation. [7] climbing stairs is another factor in ambulation, which also had a moderate positive correlation with pain. [7] the last correlation explored was between pain and the affected ability to manage personal grooming, which revealed a fair positive correlation. [7] all of these correlations were statistically significant. according to edemekong et al, there are two categories of daily activities. the first category is associated with basic skills that are required to achieve and maintain basic needs, such as eating, grooming, and transferring from one position to another. [20] the second or instrumental category requires more skill, usually mentally and physically, such as transport, cleaning, and shopping. [20] this may explain why grooming is a lower rate disability as it falls within the basic category, can be completed in supine or seated positions, and generally requires less strength and mobility than other daily tasks such as walking and climbing stairs. [20] in a study completed in spain on chronic disease patients, a disability for walking and climbing stairs existed, and when compared to other daily activities, personal grooming was one of the disabilities with a lower rating. [19] although there has been further research on the treatment of ra, it remains a limiting, chronic disease which greatly impacts on the patient’s life, abilities, and morbidity. [4] in contrast to previously mentioned international studies, this study demonstrated that the majority of ra patients were labelled as physically active. [1, 5, 6] according to current literature, participation in physical activity and exercise is both beneficial and safe for these patients, with a wide range of psychological and physiological benefits. [2, 17] some of the concerns surrounding physical activity in this population include the appropriate intensity, frequency and mode of activity, the possibility of causing further joint damage during activity, how joint pain will impact physical activity, and limited knowledge among healthcare professionals in terms of physical activity as therapeutic management. [8, 17] however, addressing these barriers and concerns will assist in encouraging and increasing activity levels in those with ra. [8, 17] preserving one’s physical abilities and decreasing additional health risks are the main original research 7 sajsm vol. 34 no.1 2022 goals for physical activity in the ra population. [2] one does need to be aware of the unique barriers (both physical and mental), motivators and perceptions that may influence physical activity levels among ra patients. [8, 17] study limitations the limitations in this study’s data collection methods include the distribution of the questionnaire using online platforms, resulting in the exclusion of ra patients without internet access. in addition, a small sample size was obtained. the omission of questions regarding the types of treatment sought was a limitation in data collection. by using the two selected questionnaires, only physical activity levels and pain outcomes were assessed. the authors acknowledge that additional questionnaires, such as a quality-of-life questionnaire, may have enhanced this study. recommendations for future research performing a pre-screening assessment before the completion of the questionnaire may assist in excluding participants who have comorbidities that may negatively impact their responses. including a question on the type of treatment that participants are seeking at the time of participation may also be beneficial, as it would allow for the analysis of and correlation between, pain levels and the different treatment modalities. lastly, replacing the pain outcomes questionnaire with the rheumatoid arthritis pain scale questionnaire may provide more accurate results, as the latter questionnaire is specific for ra. conclusion in conclusion, this study demonstrated that in a south african sample, majority of ra patients were classified as physically active. furthermore, and unexpectedly, no significant correlation was found between pain and physical activity levels. this study brings to light the importance of physical activity and exercise in the ra population, while also reminding the relevant healthcare professionals to consider the unique barriers and concerns of such participation among those with ra. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors would like to extend their gratitude to juliana van staden from statkon for her assistance with the data analysis. author contributions: all authors contributed to the design of this research and writing of the article ((i) conception, design, analysis, and interpretation of data; (ii) drafting or critical revision for important intellectual content; and (iii) approval of the version to be published). references 1. ehrman jk, gordon pm, visich ps, et al. clinical exercise physiology. 4th ed. s.l.: human kinetics, 2018:411-437. chapter in book: arthritis 2. cooney jk, law r-j, matschke v, et al. benefits of exercise in rheumatoid arthritis. j aging res 2011; 681640. 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[doi: 10.5606/archrheumatol.2020.7348] [pmid: 32637924] 17. iverson md, scanlon l, frits m, et al. perceptions of physical activity engagement among adults with rheumatoid arthritis and rheumatologists. int j clin rheumtol 2015; 10(2):67-77. [doi: 10.2217/ijr.15.3] [pmid: 26075028] 18. englbrecht m, alten r, aringer m, et al. new insights into the prevalence of depressive symptoms and depression in rheumatoid arthritis – implications from the prospective multicenter vadera ii study. plos one 2019; 14(5): e0217412. [doi: 10.1371/journal.pone.0217412] [pmid: 31136632] 19. valderrama-gama e, damián j, ruigómez a, et al. chronic disease, functional status, and self-ascribed causes of disabilities among noninstitutionalized older people in spain. j gerontol a biol sci med sci 2002; 57(11):m716–m721. [doi: 10.1093/gerona/57.11.m716] [pmid: 12403799] 20. edemekong pf, bomgaars dl, sukumaran s, et al. activities of daily living. in: treasure island (fl): statpearls publishing, 2021 jan [pmid: 29261878] https://pubmed.ncbi.nlm.nih.gov/ 29261878/ (accessed 2 november 2021). https://doi.org/10.5606/archrheumatol.2020.7348 https://dx.doi.org/10.2217%2fijr.15.3 https://doi.org/10.1371/journal.pone.0217412 https://doi.org/10.1093/gerona/57.11.m716 https://pubmed.ncbi.nlm.nih.gov/ sajsm vol. 26 no. 2 2014 43 background. the effect of ingestion of a common stimulant, caffeine, on fluid balance during exercise and recovery is not fully known. objectives. to determine the effect of caffeine on fluid balance during exercise in the heat and during a 3-hour recovery period thereafter. methods. in a randomised, controlled design, caffeine-naive participants (n=8) pedalled on a bike to achieve 2.5% baseline body mass loss in a hot environment in four separate conditions: with (c+) or without (c–) caffeine ingestion (6 mg/kg of body mass) prior to exercise, followed by (w+) or without (w–) 100% fluid replenishment (water) of the body mass loss during a 3-hour recovery period (yielding c+w+, c+w–, c–w+ and c–w–, respectively). results. mean (standard deviation) urine production was not different (p>0.05) regardless of rehydration status: 230 (162) ml (c+w–) v. 168 (77) ml (c–w–); and 713 (201) ml (c+w+) v. 634 (185) ml (c–w+). for the 3-hour recovery, caffeine ingestion caused higher hypohydration during rehydration conditions (p=0.02), but practically the mean difference in the loss of body mass was only 0.2 kg. conclusion. in practical terms, there was no evidence that caffeine ingestion in moderation would impair fluid balance during prolonged exercise in the heat or during 3 hours of recovery. s afr j sm 2014;26(2):43-47. doi:10.7196/sajsm.513 effect of caffeine ingestion on fluid balance during exercise in the heat and during recovery y zhang,1 phd; s j carter,1 msc; r e schumacker,2 phd; y h neggers,3 phd; m d curtner-smith,1 edd; m t richardson,1 phd; j m green,4 phd; p a bishop,1 edd 1 department of kinesiology, university of alabama, tuscaloosa, usa 2 department of educational studies in psychology, research methodology, and counseling, university of alabama, tuscaloosa, usa 3 department of human nutrition, university of alabama, tuscaloosa, usa 4 department of health, physical education, and recreation, university of north alabama, florence, usa corresponding author: y zhang (dr.zhang.yang@qq.com) current military doctrine places operational forces in unique situations in which soldiers are often engaged in sustained activities to achieve mission objectives. since modern military operations are both physically and cognitively demanding, and recovery can often be inadequate, there has been an increased interest in caffeine as an effective dietary supplement to counter performance deficits in military settings.[1] the use of caffeine to extend operational effectiveness in military settings is likely to be encouraged.[2] athletes have been advised to abstain from caffeine because of its diuretic effect.[3] a review by maughan and griffin[4] suggests that acute ingestion of caffeine (e.g. >250 mg) results in a short-term stimulation of urine production. meanwhile, caffeinated beverages have been reported to increase urine production during post-exercise mailto:dr.zhang.yang@qq.com 44 sajsm vol. 26 no. 2 2014 rehydration. [5] opposing this viewpoint, armstrong[6] concluded that the diuretic effect of caffeine is overstated and further may be minimised for habitual caffeine consumers. in support of this view, armstrong et al.[7] provided strong evidence for no caffeine-induced diuresis (<500 mg/24 hours) in males undergoing daily activities with no strenuous physical training. possibilities of detrimental fluid imbalances are unlikely since caffeine consumption is generally moderate and accompanied by adequate access to fluid, making rehydration non-problematic. for soldiers in combat, the risk of dehydration is higher due to pro longed operations and limited fluid availability in challenging environments, which may lead to serious health-related con sequences and affect mission success. to provide more accurate information on prescribing caffeine consumption for operational forces in hot environments, this study was designed to evaluate the influence of moderate caffeine ingestion on fluid balance during exercise and recovery. we hypothesised that fluid balance would not be affected despite caffeine ingestion. repeated prolonged operations in hot environments with restricted fluid availability represent a real-life military scenario. the findings thus have important implications for military forces engaging in sustained operations in the heat, and the results can be extended for athletes competing in adventure sports, ultradistance, and multiday sport events, and occupational workers who often consume coffee or caffeinated beverages. methods subjects eight healthy male university students volunteered for the study. all participants were physically active (e.g. exercised >4 days/ week). mean (standard deviation (sd)) age, height and body mass were 23 (4) years, 178 (4) cm and 77 (15) kg, respectively. the physical characteristics are similar to the 50th percentile means in the us army’s anthropometric database.[8] a questionnaire was administered to determine average daily caffeine consumption. only those who regularly consumed <50 mg of caffeine per day were recruited in order to create an extreme-end pattern, since a caffeine-naive population is believed to be more responsive to the effects of caffeine ingestion on fluid balance.[6] the study was approved by the local medical ethics committee. prior to beginning the study, participants were briefed on potential risks, and they signed a written informed consent form, completed a medical history questionnaire, and were acclimated to the biking exercise in the heat. procedure and design a randomised, repeated-measures design was used. each participant completed four trials: (i) exercise with caffeine (c+), (ii) exercise with no caffeine (c–), (iii) recovery-phase rehydration with tap water equal to 100% of the body mass loss (adjusted by fluid ingestion, see below) during the exercise phase (w+), and (iv) no rehydration during the recovery phase (w–), thus yielding c+w+, c–w+, c+w– and c–w–. each trial consisted of two phases: (i) exer cise-heat exposure (adjusted by fluid ingestion during exercise: 2.5% baseline body mass loss = body mass at the beginning of exercise – body mass at the end of exercise + total volume of fluid ingested during exercise = 100% fluid replenishment during recovery), immediately followed by (ii) a 3-hour recovery in a temperate environment. for a given participant, each trial was performed at the same time of day on the same day of week so that fatigue and circadian influences on hormonal secretion were minimised. participants were instructed to refrain from any caffeinated product or alcohol for a minimum 24hour period prior to testing. participants were instructed to drink a bottle of fixed volume (~500 ml) of water before sleep prior to the experiment day and another bottle of fixed volume (~500 ml) of water 2 hours before reporting to the lab to maintain a state of euhydration. on arrival at the laboratory, participants emptied their bladder and provided a urine sample, and body mass was measured (with dry polyester shorts only) (accuracy ~0.1 kg; detecto scales inc, usa). to confirm the hydration status, urine specific gravity was determined with a refractometer (sur-ne, atago inc, usa); a urine specific gravity <1.020 indicated euhydration.[9] if participants measured ≥1.020, they were asked to come back a week later. for the caffeine trials, 10 minutes prior to the exercise phase participants consumed caffeine capsules equal to 6 mg/kg of baseline body mass. this dosage has been suggested to be effective in enhancing physical endurance in caffeine-naive and habitual users.[2] then participants entered an environmental chamber (dry bulb 42oc, wet bulb 31oc, globe 40oc, relative humidity ~40%) and dehydrated to 2.5% baseline body mass loss through cycle ergometry (824e, monark, sweden). they were asked to cycle at a pace maintaining borg’s rating of perceived exertion at 12 13, which is classified as moderate intensity. [10] participants were allowed to drink bottled tap water within a fixed volume equivalent to 400 ml/hour to simulate limited fluid availability during military operations. the bottle was refilled every 60 minutes by the investigators. total fluid ingestion during this phase was recorded. this drinking pattern was similar to the volume that would adequately replace body water loss during a 4-hour military march in a temperate environment.[11] body mass (weighed with towel-dried polyester shorts only) was checked routinely. once the desired body mass loss was attained, participants were removed from the chamber. three hours of recovery immediately followed the exercise phase. the mean ambient temperature during recovery was 21.0 (0.5)°c and relative humidity was 45 (4)%. participants were instructed not to eat and to maintain a light metabolic status (e.g. reading a book, browsing the internet) throughout this period. for the two trials with fluid replenishment during the 3-hour recovery phase, a volume of tap water equivalent to 100% of the body mass loss was ingested during the first 2 hours of the recovery phase. rehydration was performed as a metered fluid ingestion (25% of volume ingested every 30 minutes for 2 hours), aiming for greater hydration efficiency.[12] this rehydration also enhances ecological validity where soldiers are more likely to replace water conservatively in case of limited fluid availability. following the 3-hour recovery, participants were weighed again (with dry polyester shorts only). statistical analysis since it is known that water ingestion exerts a mild diuretic effect,[13] all data analyses were performed for the main effect of caffeine ingestion within the rehydration or non-rehydration trials. pairwise t-tests were used to compare experimental variables. water loss (i.e. sajsm vol. 26 no. 2 2014 45 sweating and respiration) during the 3-hour recovery phase was calculated as follows: body mass (immediately after exercise phase) + 100% fluid replenishment (for w trials) − body mass (end of experimental trial) − total urine production. the percentage (distribution) of fluid replenishment (for w trials) represented the amount of ingested fluid during recovery that was either retained in the body, or had been lost in the form of urine or by means of sweating and respiration at the end of the 3-hour recovery phase. for example, water retention ratio was calculated as follows: (body mass (end of experimental trial) − body mass (immediately after exercise phase)) ÷ 100% fluid replenishment × 100%. to determine the responders and nonresponders to caffeine treatment, individual data (total urine production) were also compared by computing the least mean difference, yielding a p<0.05 at a power of 80% using the mean observed sd. all data were reported as means (sds). differences were considered to be significant at a p<0.05 level. results mean (sd) caffeine ingestion was 463 (89) mg and 459 (84) mg (range 350 600 mg), for c+w– and c+w+, respectively. no participant urinated during the exercise phase, nor defecated or vomited during the entire experimental period. urine production is given in table 1. no detectable difference was observed following caffeine ingestion (p>0.05). comparing the c+ with c– trials, there was no difference (p>0.05) in body mass or urine specific gravity between the start of the exercise phase and the end of the experimental trials (table 1). for the w– trials, fluid ingestion during the exercise phase was significantly different (p=0.03). for the w+ trials, caffeine ingestion caused a significant difference (p=0.02) in hypohydration (table 1). fig. 1 shows the relative fluid distribution following the 3-hour rehydration phase. mean (sd) water loss was no different for c+w+ (0.7 (0.4) kg) v. c–w+ (0.5 (0.3) kg) urine production water loss water retention c+w+ c–w+ fl u id r ep le n is h m en t d u ri n g 3 -h o u r re co ve ry , % 100 90 80 70 60 50 40 30 20 10 0 fig. 1. distribution of 100% fluid replenishment during 3-hour recovery. the ingested fluid during recovery was either retained in the body or lost in the form of urine, by sweating and by respiration (n=8). (c+w+ = caffeine + water; c–w+ = no caffeine + water.) table 1. fluid balance* (n=8) variable c+w– c–w– c+w+ c–w+ exercise duration (min) 95 (25) 102 (32) 95 (33) 92 (19) fluid ingestion during exercise (ml) 575 (128) 700 (239)† 550 (141) 600 (151) urine-specific gravity at start of experiment 1.012 (0.007) 1.012 (0.006) 1.012 (0.006) 1.010 (0.006) urine-specific gravity at end of experiment 1.021 (0.004) 1.023 (0.006) 1.004 (0.001) 1.004 (0.002) total urine production (ml) 230 (162) 168 (77) 713 (201) 634 (185) body mass at start of experiment (kg) 77.5 (15.0) 77.0 (14.3) 77.1 (15.2) 76.8 (15.1) body mass immediately after exercise (kg) 76.1 (14.7) 75.8 (14.1) 75.8 (14.9) 75.5 (14.8) body mass at the end of experiment (kg) 75.4 (14.6) 75.2 (14.1) 76.3 (15.2) 76.2 (15.1) change in body mass following experiment (kg) –2.0 (0.5) –1.8 (0.3) –0.8 (0.3) –0.6 (0.3) hypohydration following experiment (%) 2.6 (0.4) 2.4 (0.4) 1.1 (0.4)‡ 0.8 (0.4) c+w– = caffeine + no water; c–w– = no caffeine + no water; c+w+ = caffeine + water; c–w+ = no caffeine + water. * values are means (standard deviations). † significantly different from c+w– (p<0.05). ‡ significantly different from c–w+ (p<0.05). 46 sajsm vol. 26 no. 2 2014 (p=0.08). however, water retained in the body was significantly lower in c+w+ (0.5 (0.4) kg) v. c–w+ (0.7 (0.3) kg) (p=0.006). accordingly, the water retention ratio was greater in c–w+ (38 (12)%) v. c+w+ (27 (16)%) (p=0.01). individual analysis (fig. 2) detected that two participants were sensitive to caffeine treatment for the no fluid replenishment conditions, and three participants were sensitive to caffeine treatment for the 100% fluid replenishment conditions. discussion the objective of the study was to determine the impact of caffeine on fluid balance dur ing exercis e and re cover y. ur ine production was not different despite caffeine ingestion when no fluid replenishment was present; moreover, even with 100% fluid replenishment (water) during recover y, which is considered to be diuretic and suppressive of fluid-regulating hormones,[13] there were no treatment differences after a 3-hour recovery. current results provide additional supportive evidence that caffeine would not compromise fluid balance during and after exercise.[7,14-16] early literature has suggested that caffeine ingestion exceeding a threshold of 250 300 mg could result in an acute increase in urine production.[4] our results suggested that a mean dose of 460 mg caffeine (6 mg/kg of body mass) – enough to enhance physical and cognitive performance[2] – did not alter urine production. this supports previously reported data. in a study with a caffeine dose similar to that of our study (5 mg/kg of body mass; mean 553 mg), participants exercising at 70 75% maximal oxygen uptake to exhaustion did not experience extra urine production compared with non-caffeine conditions. [15] likewise, following cycling exercise, a moderate dose of 320 mg of caffeinated drinks did not induce additional acute body water loss compared with no caffeine.[16] the influence of exercise on the diuretic effect of caffeine is further evidenced by a study that showed that a large dose of caffeine (8.7 mg/kg of body mass; mean 586 mg) exerted a diuretic effect at rest but not during exercise.[17] this suggests that exercise is a mediating factor on caffeineinduced diuresis in healthy young males. the mean duration for the dehydration exercise phase was 1.5 hours. the effective window of time for the diuretic effect of caffeine totalled 4.5 hours in this study. a datacollection period <6 hours is often considered to cover an acute response to caffeine, and previous research has questioned whether or not such an acute response could be generalised to real-life applications.[18] while we could not totally rule out that body water loss (e.g. due to further urine production) may still occur at 6 hours, 12 hours, or after longer time periods after caffeine ingestion, it is our opinion that the current protocol duration would representatively depict a clear picture of the effect of caffeine on fluid balance under the test conditions. first, it is known that the half-life of caffeine is 2.5 4.5 hours in young individuals,[19] and neither exercise nor additional thermal stress should affect its pharmacokinetics.[20] the current 4.5-hour data collection was long enough for caffeine to exert diuretic effect. second, the literature generally suggests that the diuretic effect of caffeine starts quickly and slows later.[21] we believe that if there were a strong diuretic effect of caffeine, such an effect should override the effect of exercise during this 4.5-hour data-collection period, which did not occur in our results. furthermore, studies with either a 16-hour[14] or 24-hour[7] data-collection period with a moderate dose of caffeine (6 mg/kg of body mass) did not reveal any further diuretic effect during free-living conditions. exercise alone, or in combination with heat, could sufficiently defend total body fluid regulation even with moderate caffeine ingestion. data suggested that hypohydration was significantly higher with caffeine ingestion during rehydration trials. statistically, the 1.1 (0.4)% of dehydration for c+w+ was higher (p<0.05) compared with 0.8 (0.4)% for c–w+; biologically, however, the mean difference in body mass loss was only 0.2 kg between the two rehydration trials. we consider this statistical difference to have resulted from the difference in water loss. we rigorously controlled the 3-hour recovery phase; however, the water loss for c+w+ (0.7 (0.4) kg) tended to be higher (p=0.08) than in c–w+ (0.5 (0.3) kg), which is inconsistent with the calculated water loss of 0.4 (0.3) kg for c+w– and 0.4 (0.2) kg for c–w–. considering that urine production was similar between the two rehydration trials, the difference in water loss explained the higher water retention ratio found in c–w+. caffeine has known thermoregulatory effects. for example, it has been reported that 200 mg ingested caffeine increased metabolic rate by an average of 7% up to 3 hours after consumption.[22] it is possible that in some trials, participants (e.g. c+w+) were hotter (rectal temperature was continuously monitored for safety purposes but was not recorded for data analysis in the study) and metabolically more active for longer as a result of the thermoregulatory effect of caffeine; consequently the participants con tinued to sweat after the body mass was taken (at the end of the exercise phase), resulting in the differences seen in water loss and potentially impacting the water retention. this statistical significance leads to a conclusion that caffeine ingestion would increase hypohydration and fluid requirements during the rehydration c+w+ c–w+c+w– c–w– 1 200 1 000 800 600 400 500 400 300 200 100 0 u ri n e p ro d u ct io n , m l fig. 2. individual responses: – non-responder, – responder (n=8). (c+w– = caffeine + no water; c–w– = no caffeine + n o w a t e r ; c+w+ = caffeine + water; c–w+ = no caffeine + water.) sajsm vol. 26 no. 2 2014 47 conditions; however, such biological diff erence was minimal (~200 ml) and probably would not affect overall health and performance in practical terms. in addition, these participants were selected because they did not routinely ingest large quantities of caffeine, and thus should represent a worst-case condition. for a broader view, we also analysed individual responses (total urine production) to the caffeine treatment (fig. 2). there was some evidence within our study’s caffeine-naive population to show that some individuals were less tolerant to caffeine. this interindividual inconsistency was probably due to the metabolism of caffeine, which is influenced by lifestyle factors and human genetic variation. caffeine is metabolised in the liver by the hepatic enzyme system; the main enzyme in this process is cytochrome p450 1a2 (cyp1a2).[23] drug intake, body composition, smoking and other lifestyle factors can affect hepatic cyp1a2 activity by different magnitudes.[23] additionally, there is substantial evidence that hepatic cyp1a2 has a high rate of genetic variation, which could lead to a high degree of variability in the metabolism of caffeine.[24] these observations support our hypothesis, and it should also be noted that whereas the means were no different, individual responses were present and the impact on hydration status could be case by case. conclusion our study simulated an environmental chall enge that military forces may encounter in hot climates and has the potential for generalisation to the military community. we found moderate caffeine ingestion (mean 460 mg) did not alter urine production during and after exercise. in practical terms, caffeine ingestion did not impact the fluid balance after exercise-heat exposure. these findings would imply that the use of caffeine in moderation (e.g. 3 4 cups of regular, brewed coffee, 150 mg caffeine per 150 ml) preceding exercise would not place healthy young individuals at higher risk of hypohydration. in light of the positive effects of caffeine on physical and cognitive performance, there is no reason for restricting regular coffee consumption for modern military operations in the heat. acknowledgements. we thank the study participants. references 1. mclellan tm, kamimori gh, voss dm, et al. caffeine maintains vigilance and improves run times during night operations for special forces. aviat space environ med 2005;76(7):647-654. 2. committee on military nutrition research, food and nutrition board, institute of medicine. caffeine for the sustainment of mental task performance: formulations for military operations. washington, usa: national academy press, 2001:79-96. 3. sinclair c, geiger j. caffeine use in sports. a pharmacological review. j sports med phys fitness 2000;40(1):71-79. 4. maughan rj, griffin j. caffeine ingestion and fluid balance: a review. j hum nutr diet 2003;16(6):411-420. 5. gonzalez-alonso j, heaps cl, coyle ef. rehydration after exercise with common beverages and water. int j sports med 1992;13(5):399-406. 6. armstrong le. caffeine, body fluid-electrolyte balance, and exercise performance. int j sport nutr exerc metab 2002;12(2):189-206. 7. armstrong le, pumerantz ac, roti mw, et al. fluid, electrolyte, and renal indices of hydration during 11 days of controlled caffeine consumption. int j sport nutr exerc metab 2005;15(3):252-265. 8. gordon cc, churchill t, clauser ce, mcconville jt. anthropometric survey of us army personnel: methods and summary statistics, 1988. natick: dtic document, 1989:62. 9. armstrong le, soto ja, hacker ft jr, et al. urinary indices during dehydration, exercise, and rehydration. int j sport nutr 1998;8(4):345-355. 10. borg ga. psychophysical bases of perceived exertion. med sci sports exerc 1982;14(5):377-381. 11. nolte h, noakes td, van vuuren b. ad libitum fluid replacement in military personnel during a 4-h route march. med sci sports exerc 2010;42(9):1675-1680. [http://dx.doi.org/ 10.1249/mss.0b013e3181d6f9d0] 12. jones ej, bishop pa, green jm, et al. effects of metered versus bolus water consumption on urine production and rehydration. int j sport nutr exerc metab 2010;20(2):139-144. 13. melin b, koulmann n, jimenez c, et al. comparison of passive heat or exercise-induced dehydration on renal water and electrolyte excretion: the hormonal involvement. eur j appl physiol 2001;85(3-4):250-258. [http://dx.doi.org/10.1007/s004210100448] 14. dias jc, roti mw, pumerantz ac, et al. rehydration after exercise dehydration in heat: effects of caffeine intake. j sport rehabil 2005;14(4):294-300. 15. falk b, burstein r, rosenblum j, et al. effects of caffeine ingestion on body fluid balance and thermoregulation during exercise. can j physiol pharmacol 1990;68(7):889-892. 16. kovacs em, stegen j, brouns f. effect of caffeinated drinks on substrate metabolism, caffeine excretion, and performance. j appl physiol 1998;85(2):709-715. 17. wemple r, lamb d, mckeever k. caffeine v. caffeine-free sports drinks: effects on urine production at rest and during prolonged exercise. int j sports med 1997;18(1):40-46. 18. armstrong le, casa dj, maresh cm, et al. caffeine, fluid-electrolyte balance, temperature regulation, and exercise-heat tolerance. exerc sport sci rev 2007;35(3):135-140. [http://dx.doi.org/10.1097/jes.0b013e3180a02cc1] 19. massey lk. caffeine and the elderly. drug aging 1998;13(1):43-50. 20. mclean c, graham te. effects of exercise and thermal stress on caffeine pharmacokinetics in men and eumenorrheic women. j appl physiol 2002;93(4):14711478. [http://dx.doi.rg/ 10.1152/japplphysiol.00762.2000] 21. neuhäuser-berthold m, beine s, verwied sc, et al. coffee consumption and total body water homeostasis as measured by fluid balance and bioelectrical impedance analysis. ann nutr metab 1997;41(1):29-36. 22. koot p, deurenberg p. comparison of changes in energy expenditure and body temperatures after caffeine consumption. ann nutr metab 1995;39(3):135-142. 23. magkos f, kavouras sa. caffeine use in sports, pharmacokinetics in man, and cellular mechanisms of action. crit rev food sci nutr 2005;45(7-8):535-562. [http://dx.doi. org/10.1080/1040-830491379245] 24. daly ak. genetic polymorphisms affecting drug metabolism: recent advances and clinical aspects. adv pharmacol 2012;63:137-167. [http://dx.doi.org/10.1016/b9780-12-398339-8.00004-5] http://dx.doi.org/10.1249/mss.0b013e3181d6f9d0] http://dx.doi.org/10.1249/mss.0b013e3181d6f9d0] http://dx.doi.org/10.1007/s004210100448] http://dx.doi.org/10.1097/jes.0b013e3180a02cc1] http://dx.doi.rg/10.1152/japplphysiol.00762.2000] http://dx.doi.org/10.1080/1040-830491379245] http://dx.doi.org/10.1080/1040-830491379245] http://dx.doi.org/10.1016/b978-0-12-398339-8.00004-5] http://dx.doi.org/10.1016/b978-0-12-398339-8.00004-5] introduction participation in multi-coded sports events often involves travel to international destinations. in south africa, multi-coded teams are selected on a number of occasions during the year to participate in local competitions (sa games, sa student games); continental zonal competitions (zone 6 games); continental competitions (all africa games); and intercontinental competitions (commonwealth games, world student games and olympic games). a significant part of the preparations and tasks of a team physician includes the decisions regarding the medical supply kit. 2,12 complete preparation requires the choice of medications in sufficient quantity to cater for most medical problems that are encountered in multi-coded team events. 4,5,8 while the medical support structures of the host country might be able to supply an adequate quantity and variety of medications through a polyclinic pharmacy, it is often the case that the foreign country is unable to do so, or the labels and drug information might be presented in a foreign language. 10,11 furthermore, issues with respect to quality control and possible contamination of substances require the composition of a medical kit of sufficient variety and quantity to allow for the management of the medical conditions encountered during travel to foreign destinations. thus the choice of which compounds to include in such kit and at what quantities is often a perplexing challenge for the team physician. the aim of this report is to document the various medications and quantity usage of medications during the olympic games in athens 2004. a model is also presented to calculate the anticipated quantities of medications in future events. methods data were collected over 30 days, starting when the team arrived in athens (1 sept) until the end of the olympic games (30 sept). all original research article medication use by team south africa during the xxviiith olympiad: a model for quantity estimation for multi-coded team events abstract objective. this descriptive study was undertaken to report the medications used by the athletes and officials of team south africa at the 2004 olympic games and to provide a model for the estimation of quantities to be used for planning support to future events. setting. south african medical facility, 2004 olympic games, athens, greece. methods. the names of the medications, including the dosage and quantity of medications dispensed, were recorded in the pharmacy stock control book at the south african medical facility, 2004 olympic games, athens, greece. retrospective review of patient files and medical encounter forms was also undertaken to check against the pharmacy stock control book to ensure complete data capture of dispensed medications. main outcome measures. quantities of medications consumed during the observation period. the units of medication consumed per travelling team member were calculated by dividing the number of units (tablets, capsules, tubes, inhalers, bottles and ampoules) used during the trip by the total number of travelling team members. results. complete records of medications included in the travelling pharmacy are described. quantities of medications included ranged from single units to 2 250 units and percentage use of various medications varied from 0% to 100% of stocks. units per team member ranged from 0 to 9.43. medications were consumed from all categories of agents. the most utilised agents included correspondence: professor wayne derman uct/mrc research unit for exercise science and sports medicine sport science institute of south africa boundary rd newlands 7700 cape town, south africa tel: 27-21-659-5644 fax: 27-21-659-5633 e-mail: wayne.derman@uct.ac.za wayne e derman (mb chb, bsc (med)(hons), phd, facsm, ffims) uct/mrc research unit for exercise science and sports medicine, sports science institute of south africa, cape town 78 sajsm vol 20 no. 3 2008 the analgesics, musculoskeletal and non-steroidal anti-inflammatory agents as well as certain vitamin and mineral supplements. conclusions. this study describes the consumption of pharmacological agents by the athletes and officials of team south africa during the athens 2004 olympic games. it also provides a model to assist with the estimation of quantities of medications to be included in the travelling pharmacy for future international multicoded sports events. pg78-84.indd 78 10/17/08 12:56:27 pm medications dispensed, over this period to both athletes and officials were recorded by the attending team physicians in the pharmacy stock control book in the medical room of team sa. the names of the medications, including the dosage and quantity of medications dispensed, were recorded. retrospective review of patient files and medical encounter forms was also undertaken to check against the pharmacy stock control book to ensure complete data capture of dispensed medications. the pharmacological constituents of each medication as well as quantities of medications were forwarded to the medical authorities of the host country for importation clearance prior to leaving south africa. following completion of the travel, the above data were added to the database to allow the calculation of the percentage of medication stocks used. the units of medications per travelling team member were calculated by dividing the number of units (tablets, capsules, tubes, inhalers, bottles and ampoules) used during the trip by the total number of travelling team members. results a total of 159 team members travelled to athens. the team comprised 107 athletes from 12 sports codes and 52 officials. athletes were defined as the members of the team engaged in competition and officials were defined as team or athlete coaches, team managers, team technical staff, administration officials, medical staff and national olympic committee members. the medical consultations conducted during the 30-day period are described elsewhere in this publication. 5 the medications, active ingredients, dosage, and quantities of medications used, are shown in tables i iv. table i lists the pharmacological agents in the categories of neurological preparations, local anaesthetics, analgesics, musculoskeletal agents, autacoids and corticoids, and cardiovascular agents. table ii lists the pharmacological agents of the respiratory system, ear nose and throat drugs and drugs to manage gastrointestinal complaints. dermatological and ophthalmic preparations, antimicrobials and drugs to treat urogenital complaints are listed in table iii while table iv lists vitamin, mineral and electrolyte supplements as well as the drugs used for emergency management. quantities of medications ranged from single units to 2 250 units and percentage use of various medications varied from 0% to 100% of stocks. units per team member ranged from 0 to 9.43. medications were consumed from all categories of agents yet certain agents were used to a far greater extent. these agents included the analgesics, musculoskeletal and non-steroidal anti-inflammatory agents as well as certain vitamin and mineral supplements. discussion the ‘travelling pharmacy’ of team south africa consists of two large metal crates-on-wheels to facilitate being pushed during travel as their weight is in excess of 150 kg per container. this pharmacy is passed from one medical team to another and is used for most of south africa’s multi-coded team events, including student games, african zonal games, all africa, commonwealth and olympic/paralympic games. the pharmacy stock is checked prior to each trip for expired agents, and remaining quantities of stock from the previous trip are determined. of the many responsibilities of a team physician, the decision of which agents to take to an international destination to successfully manage a team of athletes and officials is perhaps one of the more difficult. 1 the team physicians have to be prepared to manage any medical complaint that might occur in a team of 100 500 athletes and officials. medical complaints in a squad of that size can be both diverse in nature and numerous. for example, it is not uncommon on a single trip to be expected to manage a minor outbreak of gastroenteritis, renal stones, myocardial infarction, diabetes complications, acute psychosis and a variety of musculoskeletal injuries. it is prudent to select a sufficient variety of agents and in sufficient quantities to be independent of the services provided by the host country. while host country services can be excellent and ‘stateof-the-art’, they can vary greatly depending on their geographical location and the choice of available medications as selected by the local pharmacist. 10 furthermore, certain medications might simply not be available in the host country or stock might be limited, or there might be delays in accessing host polyclinic services, leading to a delay in patient management. in some countries, the constituents of certain common medications can vary and contamination of agents can also occur. thus a comprehensive, sufficiently stocked medical supply kit is important. factors influencing the choice of which agents to include in the travelling pharmacy include: personal preference of the team physician(s); unused unexpired medications from the previous trip; the country of destination and the anticipated medical problems (e.g. travelling to an area where malaria is endemic would require certain choices and quantities of agents); the nature of the team and individual sports included in the programme (e.g. athletes involved in contact sports could require increased quantities of analgesics and anti-inflammatory agents); 7 the legislation of the country of destination (e.g. stopayne is not permitted for importation into australia); and sponsorship of products from various pharmaceutical companies. yet, estimation of quantities of these required agents is often difficult. the above list of medications provides the reader with the details of compounds included in the travelling pharmacy, the quantity taken, usage thereof and the number of units per team member consumed during the time of the athens 2004 olympic games. this latter number (which appears in column number 7) in tables i iv is particularly useful as it can be multiplied by the total number of persons in any future travelling party, and provides the physician with an estimated quantity of required medication based on a 30-day period. if the travel period is shorter (e.g. 2 weeks, the amount can be halved or if the trip is 6 weeks the number can be multiplied by 1.5). clearly, this factor provides a guide only and is likely to vary, based on the above-mentioned variables. usage of the analgesics and non-steroidal anti-inflammatory agents warrants special mention. while choice of a certain preparation over another would depend on factors including time to onset of action, desired route of administration and preference of both physician and athlete, it is of interest to note the use of the total number of units of all anti-inflammatory and analgesic tablets (and patches). the total number of units per team member for both these agents is 2.2. therefore for a team size of 300 members the total sajsm vol 20 no. 3 2008 79 pg78-84.indd 79 10/17/08 12:56:27 pm 80 sajsm vol 20 no. 3 2008 t a b l e i. m e d ic a tio n s u s e d fo r th e a th e n s 2 0 0 4 o ly m p ic g a m e s : n e u ro lo g ic a l p re p a ra tio n s , lo c a l a n a e s th e tic s , a n a lg e s ic s , m u s c u lo s k e le ta l a g e n ts , a u ta c o id s a n d c o rtic o id s a n d c a rd io v a s c u la r a g e n ts p ro d u c t/b ra n d n a m e a c tiv e /m a in in g re d ie n t w e ig h t, v o lu m e o r q u a n tity ta k e n u n its o f m e d ic a tio n u s e d % m e d ic a tio n u s e d u n its /te a m c o n c e n tra tio n p e r u n it m e m b e r n e u ro lo g ic a l p re p a ra tio n s a d co -zo lp id e m ta b s z o lp id e m h e m ita rtra te 1 0 m g 1 0 0 6 2 6 2 0 .3 9 a n xirid ta b s a lp ra zo la m 1 m g 2 0 0 0 0 0 .0 0 d o rm icu m ta b s m id a zo la m 1 5 m g 4 0 2 5 0 .0 1 d o rm o n o ct ta b s l o p ra zo la m 2 m g 6 0 2 0 3 3 0 .1 3 im ig ra n ta b s s u m a trip ta n 1 0 m g 2 4 0 0 0 .0 0 s a n d o z su lp irid e ta b s s u lp irid e 5 0 m g 5 0 0 0 0 .0 0 z o m ig ta b s z o lm itrip ta n 2 .5 m g 6 0 0 0 .0 0 z o p im e d ta b s z o p iclo n e 7 .5 m g 5 0 0 3 0 6 0 .1 9 l o c a l a n a e s th e tic s x ylo to x a m p s l ig n o ca in e h yd ro ch lo rid e 2 0 m g 1 0 0 3 3 0 .0 2 m a rca in e a m p s b u p ica ca in e h yd ro ch lo rid e 5 m g /m l 1 0 3 3 0 0 .0 2 a n a lg e s ic s d isp rin ta b s a sp irin 3 0 0 m g 5 0 0 2 6 5 0 .1 6 d o cd o l ta b s p a ra ce ta m o l, co d e in e 5 0 0 m g ; 1 0 m g 3 0 1 8 6 0 0 .11 m yp ro d o l ca p s p a ra ce ta m o l, ib u p ro fe n , co d e in e 2 5 0 m g , 2 0 0 m g , 1 0 m g 3 0 0 1 5 4 5 1 0 .9 7 n a p a m o l ta b s p a ra ce ta m o l 5 0 0 m g 5 0 0 8 0 1 6 0 .5 0 s to p a yn e ca p s p a ra ce ta m o l, co d e in e , 5 0 0 m g ; 8 m g ; 3 2 m g ; 1 5 0 m g 1 0 0 0 6 0 6 0 .3 8 ca ffe in e , m e p ro b ro m a te t ra m a h e xa l ta b s t ra m a d o l 5 0 m g 3 0 0 1 2 4 0 .0 8 t ra m a l a m p s t ra m a d o l 1 0 0 m g /2 m l 3 0 0 0 0 .0 0 m u s c u lo s k e le ta l/n s a id s b e xtra ta b s v a ld e co xib 4 0 m g 5 0 2 0 4 0 0 .1 3 c a ta fla m d ta b s d ich lo p h e n a cin p o ta ssiu m 5 0 m g 2 0 0 6 5 3 3 0 .4 1 c e le sto n e so lu sp a n a m p s b e ta m e ta zo n e a ce ta te 3 m g /m l 4 0 3 8 0 .0 2 d iclo fe n a c ta b s d iclo fe n a c p o ta ssiu m 5 0 m g 5 0 0 1 6 3 0 .1 0 e lm e ta cin to p ica l sp ra y in d o m e th a cin 1 0 m g /g 5 2 4 0 0 .0 1 m o b ic a m p s m e lo xica m 1 5 m g /1 .5 m l 2 5 0 0 0 .0 0 m o b ic ta b s m e lo xica m 1 5 m g 2 0 0 1 0 0 5 0 0 .6 3 m o b ic ta b s m e lo xica m 7 .5 m g 1 0 0 9 4 9 4 0 .5 9 t h ro m b o p h o b g e l h e p a rin 2 0 0 0 iu /2 5 g 1 0 3 3 0 0 .0 2 t ra n sa ct to p ica l p a tch e s f lu b ip ro fe n 4 0 m g 4 0 0 5 6 1 4 0 .3 5 v o lta re n e m u lg e l d iclo fe n a c d ie th yla m 5 0 g / tu b e 3 0 2 7 0 .0 1 a u ta c o id s & c o rtic o id s te lfa st ta b s f e xo fe n a d in e 1 2 0 m g 2 0 0 6 8 3 4 0 .4 3 p re d n iso n e ta b s p re d n iso n e 5 m g 1 0 0 0 0 0 0 .0 0 c a rd io v a s c u la r s y s te m a d a la t ca p s n ife d a p in e 1 0 m g 2 0 0 0 0 0 .0 0 a d co -re tic ta b s a m ilo rid e , h yd ro ch lo ro th ia zid e 5 m g ; 5 0 m g 1 0 0 0 0 0 .0 0 a m ilo re tic ta b s h yd ro ch lo ro th ia zid e 2 5 m g 3 0 0 0 0 .0 0 a n g i sp ra y iso so rb id e d in itra te 1 .2 5 m g /0 .0 9 m l 1 0 0 0 .0 0 a te n o lo l ta b s a te n o lo l 5 0 m g 5 0 0 0 0 0 .0 0 d isp irin c v ta b s a sp irin 1 0 0 m g 6 0 2 6 4 3 0 .1 6 iso p tin s r ta b s v e ra p a m il 2 4 0 m g 3 0 0 0 0 .0 0 pg78-84.indd 80 10/17/08 12:56:28 pm sajsm vol 19 no. 4 2007 81sajsm vol 20 no. 3 2008 81 t a b l e i i. m e d ic a ti o n s u s e d f o r th e a th e n s 2 0 0 4 o ly m p ic g a m e s : r e s p ir a to ry s y s te m a g e n ts , e a r n o s e a n d t h ro a t a g e n ts , a n d a g e n ts u s e d f o r g a s tr o in te s ti n a l c o n d it io n s p ro d u c t/ b ra n d n a m e a c ti v e /m a in i n g re d ie n t w e ig h t, v o lu m e o r q u a n ti ty t a k e n u n it s o f m e d ic a ti o n % m e d ic a ti o n u n it s /t e a m c o n c e n tr a ti o n p e r u n it u s e d u s e d m e m b e r r e s p ir a to ry s y s te m c o m b iv e n t in h a le r i p ra to p iu m b ro m id e , sa lb u ta m o l 2 0 µ g ; 1 0 0 µ g 1 0 0 0 .0 0 f le m e x m ix tu re c a rb o ci st e in e 2 5 0 m g /5 m l 1 0 0 0 .0 0 in fla m m id e in h a le r b u d e so n id e 2 0 0 µ g 1 1 1 0 0 0 .0 1 r o la b b e cl o m e th a so n e d ip ro p ri o n a te b e cl o m e th a so n e 5 0 µ g 3 0 1 3 0 .0 1 s e re ve n t in h a le r s a lm e te ro l 2 5 µ g 3 2 6 7 0 .0 1 s o lm u co l t a b s n -a ce ty le c ys te in e 2 0 0 m g 1 2 0 1 6 1 3 0 .1 0 s o lp h yl le x co u g h m ix tu re t h e o p h yl lin e , e to fy lli n e , 1 0 0 m g ; 1 0 m g ; 8 m g ; d ip h e n yl p yr a lin e h yd ro ch lo ri d e , 7 2 0 m g ; 3 0 0 m g /3 0 m l 2 0 2 1 0 0 .0 1 a m m o n iu m c h lo ri d e , s o d iu m c itr a te v e n to lin n e b u le s s a lb u ta m o l 5 m g 1 2 0 0 0 .0 0 v e n te ze in h a le r s a lb u ta m o l 1 0 0 µ g 2 0 0 0 .0 0 v e n tz o n e in h a le r b e cl o m e th a so n e d ip ro p ri o n a te 5 0 µ g 7 1 1 4 0 .0 1 e a r, n o s e a n d t h ro a t a u ra se p t d ro p s b e n zo ca in e , p h e n a zo n e 2 0 m g ; 1 .4 m g 1 0 0 0 0 .0 0 b o n je la c h o lin e s a lic yl a te , 0 .8 7 g ; 1 m g /1 0 g 2 0 0 0 0 .0 0 s e ta lk o n iu m c h lo ri d e b u d a fla m a q u a n a se b u d e so n id e 1 0 0 µ g /s p ra y 2 0 2 1 0 0 .0 1 c e p a ca in e lo ze n g e s b e n zo ca in e , ce ty lp yr id in iu m 2 0 m g ; 1 .4 m g 8 0 7 2 9 0 0 .4 5 c h lo ri d e c e ru m e n e x e a r d ro p s t ri e th a n o la m in e p o ly p e p tid e 1 .5 7 g /1 5 m l 2 1 5 0 0 .0 1 d a kt a ri n o ra l g e l m ic o n a zo le 2 0 m g / g 2 0 0 0 .0 0 ill ia d in n a sa l s p ra y o xy m a ta zo lin e h yd ro ch lo ri d e 0 .5 m g /m l 3 0 2 7 0 .0 1 k e n a lo g in o ra b a se t ri a m ci n a lo n e a ce to n id e 1 m g /g 4 3 7 5 0 .0 2 l o ca b io ta l t h ro a t sp ra y f u sa fu n g in e 0 .5 m g /0 .0 5 m l 4 0 9 2 3 0 .0 6 s in u m a x ta b s p a ra ce ta m o l, p se u d o e p h e d ri n e 5 0 0 m g ; 3 0 m g 1 5 0 4 4 2 9 0 .2 8 s o fr a d e x d ro p s f ra m yc e tin , g ra m ic id in , d e xa m e th a so n e 5 m g ; 0 .0 5 m g ; 0 .5 m g /m l 6 1 1 7 0 .0 1 s u d a fe d t a b s p se u d o e p h e d ri n e h yd ro ch lo ri d e 6 0 m g 8 0 2 5 3 1 0 .1 6 v ib ro ci l n a sa l g e l d im e th in d e n e m a le a te , p h e n yl e p h e ri n e , n e o m yc in 2 5 m g ; 2 5 0 m g ; 3 5 0 m g /1 0 0 m l 3 0 0 0 .0 0 g a s tr o in te s ti n a l tr a c t a d co -c yc liz in e t a b s c yc liz in e h yd ro ch lo ri d e 5 0 m g 4 0 0 0 0 .0 0 a n u so l s u p p o si to ri e s b is m u th s u b g a lla te , b is m u th o xi d e , zi n c o xi d e 5 9 m g ; 2 4 m g ; 2 9 6 m g 1 2 0 1 1 0 .0 1 b u sc o p a n t a b s h yo sc in e b u ty lb ro m id e 1 0 m g 5 1 0 2 0 0 .0 1 b u sc o p a n c o t a b s h yo sc in e b u ty lb ro m id e , d ip yr o n e 1 0 m g ; 2 5 0 m g 2 0 2 1 0 0 .0 1 c im lo c ta b s c im e tid in e 4 0 0 m g 2 0 0 0 0 0 .0 0 c o lo fa c ta b s m e b e ve ri n e h yd ro ch lo ri d e 1 3 5 m g 6 0 4 7 0 .0 3 e n o s in g le s a ch e t s o d a b ic a rb o n a te , ci tr ic a ci d , s o d iu m c a rb o n a te 2 .3 2 g ; 2 .1 8 g ; 0 .5 g 3 0 2 7 0 .0 1 f yb ro g e l o ra n g e s a ch e t i sp a g h u la h u sk 3 .5 g 9 0 2 2 0 .0 1 g a vi sc o n t a b s a lg in ic a ci d , m a g n e si u m t ri ci lic a te , a lu m in iu m -h yd ro xi d e , n a -b ic a b 5 0 0 m g ; 2 5 m g ; 1 0 0 m g ; 1 7 0 m g 1 2 0 4 3 0 .0 3 g e lu m e n a n ta ci d li q u id d ic yl o m in e , a lu m in iu m h yd ro xi d e 2 0 0 m l 1 0 2 2 0 0 .0 1 im m o d iu m t a b s l o p e ra m id e h yd ro ch lo ri d e 2 m g 6 5 0 1 6 2 0 .1 0 in te rf lo ra c a p s s a cc h a ro m yc e s 0 .1 g 4 8 0 2 0 4 0 .1 3 k a n tr e xi l s o lu tio n n e o m yc in , ka o lin , p e ct in , d ic yc lo m in h yd ro ch lo ri d e 1 0 0 m l 5 1 2 0 0 .0 1 l a ct e o l f o rt e c a p s l a ct o b a ci llu s a ci d o p h ilu s 1 0 b ill io n /s a ch e t 1 0 0 4 2 4 2 0 .2 6 l o se c m u p s o m e p ra zo le 2 0 m g 6 0 1 0 1 7 0 .0 6 m a xo lo n t a b s m e to cl o p ro m id e m o n o h yd ra te 1 0 m g 1 0 0 0 4 1 0 .0 3 n ys ta ci n o ra l s o lu tio n n ys ta ci n 2 0 m l 5 0 0 0 .0 0 r a n ih e xa l t a b s r a n iti d in e 1 5 0 m g 1 9 0 0 0 0 .0 0 s ch e ri p ro ct o in tm e n t p re d n is o lo n e , cl e m is o le , c in ch o ca in e 1 5 g 6 1 1 7 0 .0 1 s e n o ko t ta b s s e n n o si d e s a & b 7 .5 m g 2 4 8 2 5 1 0 0 .1 6 v a lo id t a b s c yc liz in e h yd ro ch lo ri d e 5 0 m g 1 8 0 4 2 0 .0 3 pg78-84.indd 81 10/17/08 12:56:29 pm 82 ’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´ sajsm vol 19 no. 4 200782 sajsm vol 20 no. 3 2008 t a b l e iii. m e d ic a tio n s u s e d fo r th e a th e n s 2 0 0 4 o ly m p ic g a m e s : d e rm a to lo g ic a l a n d o p h th a lm ic p re p a ra tio n s , a g e n ts to m a n a g e u ro g e n ita l c o m p la in ts a n d a n tim ic ro b ia l a g e n ts w e ig h t, v o lu m e o r u n its o f % m e d ic a tio n u n its /te a m p ro d u c t/b ra n d n a m e a c tiv e /m a in in g re d ie n t c o n c e n tra tio n p e r u n it q u a n tity ta k e n m e d ic a tio n u s e d u s e d m e m b e r d e rm a to lo g ic a ls a n th isa n cre a m m e p yra m in e m a le a te 2 g /1 0 0 g 4 2 5 0 0 .0 1 b a ctro b a n o in tm e n t m u p iro cin 2 g /1 0 0 g 8 5 6 3 0 .0 3 c a la m in e lo tio n c a la m in e 5 0 m l 2 0 0 0 .0 0 c a n d izo le cre a m c lo trim a zo le 2 0 0 m g /2 0 g 6 1 1 7 0 .0 1 e lo co n o in tm e n t m o m e ta so n e f u ro a te 1 m g /g 4 0 0 0 .0 0 f u sid in o in tm e n t f u sid ic a cid 2 0 m g /g m 5 1 2 0 0 .0 1 m yco ta p o w d e r z in c u n d e ca n o a te 1 0 g 6 2 3 3 0 .0 1 q u a d rid e rm o in tm e n t b e ta m e th a so n e , g e n ta m ycin , to ln a fta te , clio q u in o l 0 .5 m g ; 1 m g ; 1 0 m g ; 1 0 m g /g 5 1 2 0 0 .0 1 s to p itch cre a m h yd ro co riso n e a ce ta te 0 .1 g /1 0 g 2 0 2 1 0 0 .0 1 t ra va co rt cre a m iso co n a zo le n itra te , d iflu co rto lo n e va le ra te 1 0 m g ; 1 m g /g 1 0 2 2 0 0 .0 1 z o vira x cre a m a cylo vir 2 g 3 2 6 7 0 .0 1 o p h th a lm ic s c o vo m icin e ye d ro p s c h lo ra m p h e n ico l, n e o m ycin , 2 m g ; 5 m g ; 0 .5 m g /m l 5 0 0 0 .0 0 n a p h a zo lin e h yd ro ch lo rid e f lu o re ts e ye strip s f lu o re sce in so d iu m s trip s 1 0 0 0 0 0 .0 0 n o ve sin e ye d ro p s o xyb u p ro ca in e h yd ro ch lo rid e , 0 .4 g ; 0 .0 1 g /1 0 0 m l 2 5 2 5 0 0 .0 3 ch lo rh e xa d in e o to sp o rin d ro p s p o lym ixin b su lp h a te , 1 0 0 0 0 u ; 3 4 0 0 u ; 1 0 m g /m l 1 2 1 8 0 .0 1 n e o m ycin su lp h a te , h yd ro co rtiso n e s p e rsa lle rg e e ye d ro p s a n ta zo lin e h yd ro ch lo rid e , te tryzo lin e 0 .5 m g ; 0 .4 m g / 1 m l 5 0 0 0 .0 1 te a rs n a tu re lle d e xtra n -7 0 , h yd ro xyp ro p yl m e th ylce llu lo se 1 m g ; 3 m g /m l 4 1 2 5 0 .0 3 v isin e e ye d ro p s te tra h yd ro zo lin e h yd ro ch lo rid e 7 .5 m g / 1 5 m l 2 2 1 5 0 .0 0 u rin a ry s y s te m 0 .0 0 c itro -s o d a g ra n u le s n a c itra te , n a b ic 4 g 3 0 2 7 0 .0 1 p u rico s ta b s a llo p u rin o l 3 0 0 m g 5 0 0 0 0 .0 0 g e n ita l s y s te m c a n e ste n va g in a l ta b c lo trim a zo le 5 0 0 m g /1 g 9 1 11 0 .0 1 c yclo ca p ro n ta b s t ra n e xa m ic a cid 5 0 0 m g 3 0 0 0 0 .0 0 o vra l ta b s n o rg e ste re l, e th in yle stra d io l 5 0 0 µ g ; 5 0 µ g 2 8 0 0 0 .0 0 p ro ve ra ta b s m e d ro xyp ro g e ste ro n e a ce ta te 1 0 0 m g 1 0 0 0 0 0 .0 0 p rim o lu t n ta b s n o re th iste ro n e 5 m g 2 0 0 0 0 0 .0 0 a n tim ic ro b ia ls a d co -co -trim o xa zo le c o -trim o xa zo le 5 0 0 m g 1 0 0 0 0 0 0 .0 0 a m o xicil ta b s a m o xicillin 5 0 0 m g 5 0 0 0 0 0 .0 0 a u g m a xil ta b s a m o xicillin , cla vu lin ic a cid 2 5 0 m g ; 1 2 5 m g 1 5 0 5 5 3 7 0 .3 5 c ip ro b a y ta b s c ip ro flo xa cin 5 0 0 m g 4 5 0 4 0 9 0 .2 5 d o xycyclin e ta b s d o xycyclin e 1 0 0 m g 1 0 0 0 0 0 0 .0 0 e rym ycin ta b s e ryth ro m ycin ste a ra te 2 5 0 m g 5 0 0 0 0 0 .0 0 f a sig yn ta b s t in id a zo le 5 0 0 m g 8 0 0 0 .0 0 f la g yl ta b s m e tro n id a zo le 4 0 0 m g 6 0 0 0 0 0 .0 0 in te rflo ra ca p s s a cch a ro m yce s b o u la rd ii 2 5 0 m g 1 0 0 1 0 1 0 0 .0 6 r e le n za b liste rs & d iskh a le r p a cks z a n a m ivir 5 m g 1 0 0 0 0 .0 0 r e tro vir/3 t c p o st e xp o su re p a cks z yd o vu d in e 3 t c la m ivu d in e 1 0 0 m g ; 1 5 0 m g 2 0 0 0 .0 0 v e rm o x ta b s m e b e n d a zo le 5 0 0 m g 7 0 0 0 0 .0 0 z in n a t ta b s c e fu ro xim e 2 5 0 m g 4 0 1 0 2 5 0 .0 6 z ith ro m a x ta b s a zith ro m ycin 5 0 0 m g 9 0 2 7 3 0 0 .1 7 pg78-84.indd 82 10/17/08 12:56:29 pm sajsm vol 19 no. 4 2007 83sajsm vol 20 no. 3 2008 83 t a b l e i v . m e d ic a ti o n s u s e d f o r th e a th e n s 2 0 0 4 o ly m p ic g a m e s : v it a m in , m in e ra l a n d e le c tr o ly te p re p a ra ti o n s a n d e m e rg e n c y d ru g s p ro d u c t/ b ra n d n a m e a c ti v e /m a in i n g re d ie n t w e ig h t, v o lu m e o r q u a n ti ty t a k e n u n it s o f % m e d ic a ti o n u n it s /t e a m c o n c e n tr a ti o n p e r u n it m e d ic a ti o n u s e d u s e d m e m b e r v it a m in s m in e ra ls a n d e le c tr o ly te s e le ct ro p a c sa ch e ts n a c l, n a -b ic a rb , k c l, d e xt ro se m o n o h yd ra te 0 .4 g ; 0 .5 g ; 0 .3 g ; 4 g 3 0 11 3 7 0 .0 7 f e rr im e d a m p u le s i ro n p o ly is o m a lto se 1 0 0 m g / 2 m l 7 5 0 0 0 .0 0 f e rr o -f o lic t a b le ts i ro n s u lp h a te , fo lic a ci d , a sc o rb ic a ci d 5 2 5 m g ; 3 5 0 m g ; 5 0 0 m g 3 0 0 3 0 1 0 0 .1 9 l e n n o n -v it b c o a m p u le s v it b 1 , b 6 , b 1 2 2 m l 4 0 6 1 5 0 .0 4 n e u ro b io n a m p u le s v it b 1 , b 6 , b 1 2 1 0 0 m g ; 1 0 0 m g , 1 m g 2 1 1 2 5 7 0 .0 8 n e u ro b io n t a b le ts v it b 1 , b 6 , b 1 2 1 0 0 m g ; 2 0 0 m g , 2 0 0 µ g 1 0 0 0 0 0 .0 0 u lti m a g t a b le ts m a g n e si u m c h lo ri d e , zi n c o xi d e 6 6 0 m g ; 6 m g 8 0 7 8 9 8 0 .4 9 v ita -t h io n s a ch e ts v it c , v it b 1 , g lu ta th io n , n a -a d e n o si n e t ri p h o sp h a te , 5 0 0 m g ; 2 m g ; 0 .5 m g ; 0 .5 m g ; c a -i n o si to l h e xa p h o sp h a te 1 0 0 m g 2 2 5 0 1 5 0 0 6 7 9 .4 3 0 .0 0 e m e rg e n c y d ru g s /a m p o u le s 0 .0 0 s te ri le w a te r s te ri le w a te r 1 0 m l 1 0 2 2 0 0 .0 1 a m in o p h yl lin a m in o p h yl lin 2 5 0 m g /m l 1 0 0 0 0 .0 0 d e xt ro se d e xt ro se 5 0 m l; 5 0 % s o lu tio n 1 0 0 0 0 .0 0 a d re n a lin e a d re n a lin e 1 m l 1 /1 0 0 0 2 0 0 0 0 .0 0 p h e n e rg a n p ro m e th a zi n e h yd ro ch lo ri d e 2 5 m g 1 0 0 0 0 .0 0 c e le st o n e b e ta m e ta zo n e s o d iu m 1 m l 1 0 0 0 0 .0 0 a tr o p h in a tr o p in e s u lp h a te 1 m g / m l 1 0 0 0 0 .0 0 m a xo lo n m e to ch lo p ra m id e 1 0 m g 1 0 0 0 0 .0 0 s te m iti l p ro ch lo rp e ra zi n e 1 2 .5 m / m l 2 0 0 0 0 .0 0 s co p e x h yo sc in e n -b u tr o b ro m id e 2 0 m g /1 m l 3 2 2 6 0 .0 0 v a liu m d ia ze p a m 1 0 m g /2 m l 1 5 0 0 0 .0 0 k e fli n c e p h a lo th in s o d iu m 1 g 1 0 0 0 .0 1 te ta n u s va cc in e t e ta n u s va cc in e 1 m l 2 0 0 0 .0 0 m a g n e si u m s u lp h a te m a g n e si u m s u lp h a te 5 m l 1 0 0 0 0 .0 0 r e m ic a in e 2 % l ig n o ca in e h yd ro ch lo ri d e 2 0 m g /m l 5 0 0 0 .0 0 m o rp h in e s u lp h a te m o rp h in e s u lp h a te 1 0 m g /m l 1 0 0 0 0 .0 0 p e th id in e p e th id in e h yd ro ch lo ri d e 2 5 m g /m l 1 0 0 0 0 .0 0 s o lu co rt e f h yd ro co rt is o n e s o d iu m 1 0 0 m g /2 m l 3 0 0 0 .0 0 u re tic f u ro se m id e 2 0 m g 1 0 0 0 0 .0 0 pg78-84.indd 83 10/17/08 12:56:30 pm 84 ’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´ sajsm vol 19 no. 4 200784 sajsm vol 20 no. 3 2008 number of doses of these agents would be 660 tablets/capsules/ patches of non-steroidal anti-inflammatory agents and 660 tablets capsules of analgesic compounds based on a 30-day trip. this figure does not include injectable agents, the usage of which is indicated in table i. the true consumption of non-steroidal anti-inflammatory agents during this event was however somewhat underestimated in this calculation, as it does not take into account flurbiprofen patches and other transdermal anti-inflammatories dispensed by the physiotherapists, or self-medication by the athletes using their own medication supplies. 14 it is thus apparent that double or tripledosing of these agents regularly occurs and as these agents are not without side-effects, 3,6,9 it is important that good communication exists between the physicians and physiotherapist with respect to dispensing of non-steroidal anti-inflammatory agents, and that the athletes are educated with respect to judicious use of these medications. 13 it is therefore suggested that dispensing of all medications is conducted by the team physicians only. furthermore, dispensing of small quantities of these agents with frequent reevaluation of the patient is preferable to dispensing larger quantities in original packaging. indeed, this recommendation extends to the use of all medicinal compounds listed and not only the analgesics and anti-inflammatory agents. in conclusion, this study describes the consumption of pharmacological agents by the athletes and officials of team south africa during the athens 2004 olympic games. it also provides a model to be used as a tool to assist with the estimation of quantities of medications to be included in the travelling pharmacy for future international multi-coded sports events. acknowledgements the author would like to thank dr christa janse van rensburg, dr maki ramagole and dr harald adams for their tireless efforts in collection of the data used in this study. references 1. alaranta a, alaranta h, helenius i. use of prescription drugs in athletes. sports med 2008; 38: 449-63. 2. buettner cm. the team physician’s bag. clin sports med 1998; 17: 365-73. 3. corrigan b, kazlauskas r. medication use in athletes selected for doping control at the sydney olympics (2000). clin j sport med 2003; 13: 33-40. 4. derman we. medical care of the south african olympic team – the sydney 2000 experience. south african journal of sports medicine 2003; 15: 22-5. 5. derman we. profile of medical and injury consultations of team south africa during the xxviiith olympiad, athens 2004. south african journal of sports medicine 2008; 20: 72-76. 6. huang sh, johnson k, pipe al. the use of dietary supplements and medications by canadian athletes at the atlanta and sydney olympic games. clin j sport med 2006; 16: 27-33. 7. junge a, langevoort g, pipe a, et al. injuries in team sport tournaments during the 2004 olympic games. am j sports med 2006; 34: 565-76. 8. katelaris ch, carrozzi fm, burke tv. allergic rhinoconjunctivitis in elite athletes: optimal management for quality of life and performance. sports med 2003; 33: 401-6. 9. lippi g, franchini m, guidi gc, kean wf. non-steroidal anti-inflammatory drugs in athletes. br j sports med 2006; 40: 661-2. 10. milne cj, shaw mt. travelling to china for the beijing 2008 olympic games. br j sports med 2008; 42: 321-6. 11. shaw mt, leggat pa, borwein s. travelling to china for the beijing 2008 olympic and paralympic games. travel med infect dis 2007; 5: 365-73. 12. simon lm, rubin al. traveling with the team curr sports med rep 2008; 7: 138-43. 13. smith bj, collina sj. pain medications in the locker room: to dispense or not. curr sports med rep 2007; 6: 367-70. 14. tscholl pm, junge a, dvorak j. the use of medication and nutritional supplements during fifa world cupstm 2002 and 2006. br j sports med 2008; 42: 725-730. sports physician – johannesburg an associate to join an established practice working out of 2 multidisciplinary sports clinics in johannesburg is sought. the suitable candidate must: • be registered with the hpcsa • have postgraduate sports medicine qualifications • preferably have some experience working with athletes and sports teams interested candidates should e-mail their cvs to sandy at jpat@mweb.co.za pg78-84.indd 84 10/17/08 12:56:30 pm 28 sajsm vol. 25 no. 1 2013 review several international rugby unions, including the south african rugby union, have adopted the long-term athlete development (ltad) model, which is based on physiological principles that categorise players into specific stages of development. the original model proposes different age categories for boys and girls within each specific stage of development. this review: (i) discusses the current state of junior female rugby in south africa; (ii) discusses the evidence for gender-specific differences in the ltad model; and (iii) recommends a future strategy for ltad within female rugby in south africa, considering the current approaches of other international unions. s afr j sm 2013;25(1):28-35. doi:10.7196/sajsm.461 the state of women’s rugby union in south africa: recommendations for long-term participant development m posthumus uct/mrc research unit for exercise science and sports medicine, department of human biology, sport science institute of south africa, university of cape town, cape town, south africa m posthumus, phd corresponding author: m posthumus (mposthumus@me.com) the most common model used to develop and nurture talent across all sporting codes is the long-term athlete or participant development (ltad or ltpd) model. prior to the implementation of structured talent-development plans, too much emphasis was placed on competition and results among paediatric and adolescent athletes.[1,2] the ltad model is based on physiological principles which allow players to be categorised into specific stages of development. [3] the classic stages of development for late specialisation sports, such as rugby, include the ‘fundamental’, ‘learning to train’, ‘training to train’, ‘training to compete’ and ‘training to win’ phases.[3] several international rugby unions, including the south african rugby union (saru), have adopted the same terminology for these phases. saru has outlined potential stages of development for boys according to age: ‘fundamental’ – age 6 9 years (u7 u9); ‘learning to train’ – age 10 13 years (u10 u13); ‘train to train’ – age 14 16 years (u14 u16); ‘training to compete’ – 17 18 years (u17 u19); and ‘training to win’ – age ≥19 years. these categorisations have been used as a point of departure and, based on available literature, are explored further here in terms of whether or not they are indeed scientifically supported, justifiable and feasible for both men’s and women’s rugby. the ltad model was originally developed based on the concept of ‘windows of trainability’[3] – specific periods in a young athlete’s life when he/she is uniquely sensitive to specific modes of training and is capable of enhanced adaptation.[3] as biological maturity varies greatly among young athletes, it is suggested that a practical solution would be to use a non-invasive measure of biological maturity. consequently, peak height velocity (phv) is used as the critical reference point for the design of optimal individual development programmes. whether windows of trainability actually exist has been debated in the scientific literature. here, the relevant evidence pertaining to girls is reviewed in greater detail. as outlined above, saru has suggested age-group recommendations for the various stages of their ltpd plan. although the stages of development are well described for men’s rugby, women’s rugby remains less structured and defined within south africa (sa) and in several other international rugby unions. consequently, the objective of this article is to provide a best-practice framework for structuring women’s rugby in sa. here, relevant peer-reviewed scientific literature is reviewed to establish best-practice guidelines for the development of ltad within women’s rugby; more specifically, the evidence for a similar or altered ltpd structure for women’s rugby in sa is reviewed. review of current structures in sa there is currently no uniform structure for girl’s rugby within sa. to document the structures currently in place within each provincial union, the female rugby co-ordinators from each union were contacted telephonically and interviewed (table 1). although girls and women play rugby within all sa provincial unions, the extent of participation varies greatly. certain provincial rugby unions have several clubs and schools which play structured league matches on a weekly basis across most age categories, while other unions have no female participants, or merely have a small group of girls and women who practise together to prepare for, as an example, the u16 interprovincial week (table 1). within sa there is currently no standardised format for introducing young girls to rugby and developing their fundamental rugby skills. certain provincial unions do introduce the game of rugby to young girls (u6 u11) through tag rugby, mini-rugby or touch rugby; however, this is not standard and a number of unions offer no structure for their introductory participation. the majority of introductory rugby structures for girls involve mixed-gender participation with boys. furthermore, although certain unions do mailto:mposthumus@me.com sajsm vol. 25 no. 1 2013 29 introduce the game of rugby to young girls, participation is mostly lost up until the u16 age group. most sa provincial unions have a structured plan for the participation of girls in the u16 age group, predominantly due to a saru-administered u16 inter-provincial girls rugby tournament. the extent to which u16 girls’ rugby is structured is mostly reliant on the number of girls playing rugby in each specific union. a union such as border has a large number of school and club teams (approximately 80 teams), which play against each other at regular rugby festivals, whereas other unions do not have any clubs or schools which play table 1. a brief description of all junior (u6 u18) women’s rugby activities in the sa rugby provincial unions* province activities blue bulls limpopo young girls from the ages of 6 8 years play mini-rugby with the boys. at u13 level there is a festival where u13 girls play 15-a-side rugby. for high school girls, there is only an u18 league. the u16 provincial team is selected from these league matches. blue bulls tshwane young girls from the ages of 6 8 years play mini-rugby with the boys. at u10 level there is a tag school league. there is an interschool/club league for u14, u16 and u18 girls. they play 15-a-side rugby. boland girls are only introduced at u16 level. they play an interschool competition in preparation for the national interprovincial tournament. u18 girls play 7-a-side rugby. border girls are introduced to the game only at u13 level. there is a large club and school structure for u13 and u16 15-a-side rugby. the u13 and u16 teams play in regional festivals. u18 girls join and play within the senior club structures. eastern province young girls are introduced to the game at u9 level. they play touch rugby and there are festivals arranged for competition at this level. there are both u12 and u16 structured leagues. at u12 level, girls play 7-a-side rugby. at u16 level, girls play 15-a-side rugby. falcons there are currently no structures for junior women’s rugby in this region. there is insufficient participation to put together an u16 provincial team. even at senior level there is no structured club competition, merely a group of players who practise together. free state young girls are introduced through tag rugby at u6 u8 level. there are no structures at intermediate levels. there is no school or club structure within the province. there are training groups organised by the province to prepare an u16 provincial team for the u16 provincial tournament. there is an u18 structure for playing 7-a-side. golden lions young girls are introduced to the game playing tag rugby. there are structured competitions where girls and boys play tag rugby together at u11 and u13 level. for high school girls, there are u16 and u18 competition structures. regular festivals are arranged where the 6 youth clubs within the union play against each other. griffons young girls are introduced to the game at u9 and u11 level through mini-rugby. young boys and girls play separately. there is an interschool/club competition for u16 and u18 girls. there is no structured plan for girls between the age groups of u12 and u16. griquas girls are currently only introduced to the game at u18 level. u16 girls participate in the u18 age category. although there are no structured competitions, there are clubs that have groups of girls who participate in camps, trials and occasional festivals. there have also been 7-a-side festivals previously, arranged specifically for u16 girls. kwazulu-natal the u9, u11, u13, u14 and u15 age groups play tag and touch rugby. u9 girls are introduced to the game and play with the boys. these junior age groups play against other schools. only at u16 level do the girls play competitive 15-a-side rugby. they play interschool/club rugby and a provincial team is represented at the national u16 week. there is also an u18 competition between schools and clubs. leopards girls play informally from the u11 age group onwards. they play with boys, where they participate in noncontact practises, but do not play any matches or partake in competitions. girls only start playing at u16. they play 15-a-side rugby in preparation for the national inter-provincial tournament. there is no school or club competition system. mpumalanga girls are introduced into rugby structures at u16 level. there are 7 youth clubs in the province, which play rugby at u16 and u18 level. they play regular development tournaments against each other in 7-a-side format. the provincial 15-a-side team is selected from the 7-a-side tournaments. south western districts girls are introduced into rugby structures at u16 level. there are a few clubs and schools that play rugby, but there is no structured competition. there are both u16 and u18 teams within the schools and clubs. ‘friendlies’ are arranged between the different teams as a form of competition. western province young girls are introduced into the game through playing mini-rugby at u9 level. there is a school league that accommodates u13s, u16s and u18s. u13s and u18s play 7-a-side. the u16 girls play 15-a-side rugby in preparation for the inter-provincial u16 tournament. *all descriptions were collected from telephonic interviews with the respective provincial union co-ordinators of female rugby (particulars available from the author). 30 sajsm vol. 25 no. 1 2013 women’s rugby. the unions without any clubs or schools that play women’s rugby select their provincial team from a relatively small group of girls who practise as a team to represent their union in the inter-provincial u16 tournament. currently, after girls across all sa provincial unions are introduced to rugby at u16 level, there is no standardised plan for continued participation. although there are club and school leagues within certain provinces that continue playing at u18 level, certain unions adopt the 7-a-side format at u18 level and others have absolutely no competition structure at u18 level. in the latter, girls either stop playing rugby or play within the senior women’s structures. at the senior level, there are women’s rugby club structures within most provincial unions. the extent of participation across all junior levels is summarised in table 2. all descriptions were collected from telephonic interviews with each respective provincial union’s coordinator for female rugby (particulars available from the author). table 2. a summary of the extent of junior (u6 u18) women’s rugby in sa rugby provincial unions province/union are girls introduced to the game at u6 u10 level? is there any structure for participation from u11 to u15? is there any structure for participation at u16 level? is there any structure for participation at u18 level? blue bulls limpopo yes (u6 u8 play minirugby) yes (u13 15-a-side competition) no (u16 girls play in the u18 structure) yes (interschool/club league for u18) blue bulls tshwane yes (u6 u8 play minirugby; u10 play tag rugby) yes (u14 interschool/ club league) yes (u16 interschool/ club league) yes (interschool/club league for u18) boland no no yes (u16 interschool/ club league) yes (7-a-side league for u18) border no yes (u13 school/club league) yes (u16 school/club league) no (u18 girls participate in senior rugby) eastern province yes (u9 girls play touch rugby) yes (u12 girls play 7-a-side in a structured league) yes (u16 school/club league) no falcons no no no no free state yes (u6 and u8 play tag rugby) no yes (there are training groups organised to select a provincial team; no competitions) yes (7-a-side league for u18) golden lions no yes (tag competition for u11 and u13; boys and girls mixed) yes u16 interschool/club league yes u18 interschool/club league griffons yes (u9 and u11 play mini-rugby) no yes (u16 interschool/ club league) yes (u18 interschool/club league) griquas no no no (u16 girls play in the u18 structure) yes (groups of girls who practise together and play 7-a-side) kwazulu-natal yes (u9 and u11 play tag and touch rugby) yes (u13 and u14 play tag and touch rugby) yes (u16 interschool/ club league) yes (u18 interschool/club league) leopards no no (girls play informally with boys, but no girl structure) yes (u16 girls play 15-a-side rugby in preparation for the provincial tournament) no mpumalanga no no yes (u16 7-a-side tournaments) yes (u18 7-a-side tournaments) south western districts no no yes (u16 school/club teams) yes (u18 school/club teams) western province yes (there is u9 minirugby) yes (there is an u13 7-a-side school league) yes (there is an u16 interschool/club league) yes (there is an u18 7-a-side school league) sajsm vol. 25 no. 1 2013 31 summary • there is no consistent participation structure in women’s rugby in sa at a junior level (u6 u18). • currently, in the majority of provincial unions, participation structures revolve around the u16 inter-provincial tournament organised by saru. • less than half of the provincial unions (47% or 7/15; 1 province was sub-divided) introduce rugby to young girls. • only 20% (3/15) of the provincial unions claim to have girls participating across all the junior age categories. • the lack of progressive age-group structures results in girls playing above their specific age group. • there are no ltad plans for women’s rugby in any of the provinces. gender-specific differences in the ltad model as mentioned above, the ltad or ltpd model was originally developed based on the concept of ‘windows of trainability’[3] – specific periods in a young athlete’s life when he/she is uniquely sensitive to specific modes of training and capable of enhanced adaptation. the stages of the ltpd model theoretically align with these periods of putative enhanced adaptation (fig. 1). as the objective is to formulate evidence for a similar or altered ltpd structure for women’s rugby, when compared with men’s rugby, the rationale for age categories in the original balyi and hamilton[3] model is reviewed here and appraised. the fundamental stage the objective of the first stage of the ltpd plan is termed the ‘fundamental’ or physical literacy stage.[3] the original ltpd model[3] recommended that boys aged 6 9 years and girls aged 6 8 years participate in this developmental focus period. the objective of this stage is to learn the fundamental movement skills, with emphasis on physical literacy and the ‘abcs’ – an acronym for ‘athleticism, balance, co-ordination and speed’.[3] fundamental movement and sport skills include walking, running and jumping, and catching, hopping and galloping, respectively. these activities are the basis of a wide range of physical activities and sport situations.[4] this fundamental stage, as originally proposed,[3] occurs approximately at a similar age to reports of peak brain maturation. rabinowicz[5] noted that peak brain maturation occurred between the ages of 6 8 and 10 12 years. furthermore, several studies have investigated the effect of training on fundamental sport skills.[6,7] although these studies were not specifically performed among girls, they demonstrate that a longterm school-based intervention can improve physical literacy among 6 9-year-olds; however, a 6-year follow-up demonstrated that the year-long intervention failed to result in long-term improvements in physical literacy.[6] although the development of fundamental sports skills are undeniably important,[8] there is a lack of scientific evidence to support the existence of a defined or critical period of enhanced adaptation. furthermore, there is also a lack of evidence for the gender disparities in age at which such an accelerated adaptation window occurs. the fundamental stage of development is also reported to include the first, of two, windows of accelerated adaptation to speed.[3] this window is reported to occur at age 6 8 years for girls, and 7 9 years for boys. this period was reported to align with accelerated increases in speed among boys and girls, most probably due to neuromuscular factors.[3] it has been suggested that 2 periods of accelerated adaptation to speed occur: the first between the ages of 5 and 9 years in both males and females, and the second between the ages of 12 and 15 years in boys and at 12 years in girls.[9,10] from the age of 12 years, the progression of maximal speed development is greatly reduced in females.[11] the disparity in maximal speed development has been proposed to be due to body dimensions, body composition and related maturational changes.[11,12] the first period of accelerated adaptation has been suggested to be linked to central nervous system development and improved co-ordination.[9-11,13] however, no studies have measured training-induced adaptation to maximal speed development in children aged 5 9 years; therefore, there is no evidence to support the first period of enhanced adaptation fig. 1. the ltad plan originally proposed by balyi and hamilton,[3] including the windows of trainability that each stage is based upon for males (top) and females (bottom). adapted from balyi and way.[1] 32 sajsm vol. 25 no. 1 2013 to speed. although an increased muscle function during adolescence theoretically supports the second period of speed adaptation, butterfield et al.[12] found no association between maturational factors (growth rate and body mass) and improved maximal running speed. this second period of adaptation has also been reported to be due to hormone-related fast-twitch muscle-fibre hypertrophy. however, research shows that the trainability of speed during adolescence is similar to that during pre-adolescence.[14] furthermore, it has been reported that the magnitude of training-related changes in speed in pre-adolescent and adolescent boys remains lower than that of changes in adults.[15] in addition, the adaptations to speed are lost with de-training.[15] the periods of increased adaptation surrounding the pre-adolescent and adolescent periods remain difficult to study due to the multi-factorial nature of speed development and the plethora of maturational changes during this period of development. there is, however, no strong scientific evidence to support these two windows/ periods of adaptation for speed development. moreover, there is no evidence to support the theory that males and females should emphasise speed training at different ages. the ‘learning to train’ stage the second stage of development is termed the ‘learning to train’ stage. balyi and hamilton[3] recommended that boys between the ages of 9 12 years and girls aged 8 11 years participate in this developmental focus period. the objective of this stage is to build overall sports skills. this stage is aligned with the ‘window of accelerated adaptation to motor co-ordination’.[3] although this window is aligned with a period of peak brain maturation, there is also no convincing scientific evidence for segregating males and females at this stage of development. as discussed previously, periods of peak brain development occur at 6 8 years and 10 12 years.[5] although this aligns with the window of opportunity for physical literacy[5] and motor co-ordination,[16] there is no evidence that this period offers greater adaptation to training. the ‘training to train stage’ the third stage of development in the ltpd model is termed the ‘training to train stage’. balyi and hamilton[3] recommended that boys aged 12 16 years and girls aged 11 15 years participate in this developmental focus period. the objective of this stage is to build an aerobic base, build strength towards the end of the phase and further develop sport-specific skills. this stage is aligned with the ‘window of accelerated adaptation to aerobic and strength training’ and includes the onset of peak height velocity (phv)[3] – the point in adolescence at which the rate of vertical growth is the greatest. studies have shown that peak development of oxygen uptake occurs in the periods after phv and puberty.[17,18] a review of longitudinal studies concluded that the peak development of aerobic capacity occurs between the ages of 12 and 16 years in boys and girls.[19] certain cross-sectional studies, however, have reported that the peak aerobic development occurs between the ages of 10 and 16 years for boys and 7 and 13 years for girls. the age at which optimal aerobic development occurs therefore remains inconclusive.[19] furthermore, considering the evidence, a window of trainability for aerobic capacity also remains inconclusive. weber et al.[20] suggested that decreased sensitivity to aerobic capacity occurs during the middle of phv and that there is an increased sensitivity either side of the middle of phv. alternatively, rowland[21] found a 10% and a 9% increase in peak oxygen uptake in the period before phv in boys and girls, respectively. there are, therefore, clear discrepancies in the literature surrounding the evidence for the actual window of trainability for aerobic performance.[18] although studies have suggested that phv is a determinant of this window, there is no clear evidence of how this window is different in boys and girls. further longitudinal studies with precise assessment of training stimuli are required to further investigate this window.[7] balyi and hamilton[3] reported 2 windows of accelerated adaptation for strength training in females: the first at the onset of phv, and the second at the onset of menarche. however, there are no reported studies on strength-training responses in adolescents where phv was considered or measured with adequate controls.[7] only 1 of 3 studies which measured adaptations to strength training found an association between magnitude of adaptation and maturational level.[19,22,23] vrijens[19] found greater improvements in arm and leg strength in post-pubertal (mean age 16.8 years) adolescents compared with prepubescent adolescents (mean age 10.5 years). there were no significant differences in the magnitude of strength adaptation between the two maturational groups in the other 2 studies.[22,23] the evidence for the existence of a strength-training window of opportunity is therefore limited and no longitudinal studies have investigated the magnitude of strength adaptation within various stages of development in females. therefore, there is no scientific rationale for separating boys and girls at the ‘training to train’ stage. the ‘training to compete’ stage the fourth stage in the ltpd model is termed the ‘training to compete’ stage. balyi and hamilton[3] recommended that boys aged 16 18 years and girls aged 15 17 years participate in this developmental focus period. the objective of this stage is to optimise fitness preparations, performance and sport-, individualand position-specific skills.[3] it is reported that this stage includes the second ‘window of accelerated adaptation to strength’ for males and females.[3] however, as described above, further research is required. the ‘training to win’ stage the fifth stage of development in the ltpd model is termed the ‘training-to-win’ stage. balyi and hamilton[3] recommended that men aged ≥18 years and women aged ≥17 years participate in this developmental focus period. the objective of this stage is to maximise fitness preparations, performance and sport-, individualand position-specific skills. this is the final phase of athletic preparation. summary • the ltpd model has aligned itself to emphasise training capacities during specific ‘windows of opportunity’ • however, scientific data to support the concept of windows of opportunity are lacking • there is a lack of scientific evidence to support the concept of different windows of opportunity and therefore different age separation of the ltpd stages for girls v. boys • a uniform ltpd model should be used for both boys and girls. sajsm vol. 25 no. 1 2013 33 how other international unions have adapted the ltad model for females due to the available resources and performances of their respective national teams, this discussion includes the development plans adopted by australia, canada, england, ireland and new zealand (online resources listed in appendix i). the plan adopted specifically for girls’ rugby development is discussed here. among the 5 international unions described, only canada, england and ireland have blatantly structured their development programme according to balyi and hamilton’s ltad model.[3] however, each international union has adopted a structured model that divides participation into specific age categories. since balyi,[1,3] who first described the ltad model, advises canadian and uk sport, their respective models follow the original balyi-described model either directly or with only slight modification. both england and canada have allocated different ages for boys and girls within each of the developmental stages. the canadian ltad model follows the original ltad model exactly as described by balyi and hamilton[3] (fig. 1). the england model has been adapted slightly for girls from the original model by combining the ‘learning to train’ and ‘training to train’ stages. besides this, girls still enter the following stages 1 year sooner than boys. although the ireland model incorporates the ltad developmental stages, both girls and boys enter the respective developmental stages at the same age. the ltad model seems less influential in the australian and new zealand developmental models and strategic plans. there are no female-specific plans and details available for australia and new zealand, and it can therefore be assumed that the females’ developmental plan and structure is no different to that of the males. the new zealand black ferns strategic plan, a high-performance plan for women, is currently in the process of being developed and will be implemented in 2013. no details are currently available. it is agreed (australia, canada and england) that girls in the u12 age group and younger may participate in mixed-gender modified competitions and matches. within the england model, u12 girls may apply for dispensation to play down in the u11 age category of the england rugby football union (rfu) continuum. in addition, clubs with enough girls participating may field u12 girls’ teams against each other. these u12 girls’ matches are played under the laws of u10 mini-rugby outlined in the rfu continuum. after the u12 age band, england, australia and ireland introduce game and law variations for girls’ rugby. in england, u15 girls aged 12 15 years play a modified 13-player version of the game. in australia, participation is low and schools are encouraged to arrange competition for girls aged 13 18 years to play a non-contact, modified version of the game, called walla rugby. in australia, talented girls may play senior rugby. in ireland, only slight law variations differentiate the boys’ and girls’ games within all junior age bands. in canada, boys and girls play the same format of the game within each stage of the ltad model. the similarities and differences between the international unions are summarised in fig. 2. summary • the structure adopted by each international rugby union is unique • it is common that u12 girls and younger may participate in mixed-gender rugby 6 7 8 9 10 11 12 13 14 15 16 17 18 19 australia canada england ireland new zealand boys girls boys girls boys girls boys girls boys girls u6 tag u7 tag u8 u9 u10 u11 u12 u10 flagu8 flag u6 tag u7 tag u8 u9 u10 u11 u12 u13 kid’s pathway u10 modi�ed contact u14 boys u16 boys u15 girls u10 u11 u12 u13 boys u14 boys u13 u19 (standard 15-man) organise modi�ed version of rugby. schools are encouraged to arrange for girls 13-18 to play non-contact modi�ed version of the game, walla rugby. in australia, talented girls may play senior rugby. u18 boys u18 girls u15 boys u16 boys u17 boys u19 boys u15 age band (for u13) u18 competition u19 boysu10 u11 u12 stage 1 stage 2 stage 3 u8 u9 small black development plan u12 girls may play u11 age band rugby (mixed) u8 minicontact u7 minitag u13 boys u14 boys slight law variations for girls, stages 1 3 u15 boys u16 boys u17 boys slight law variations for gilrs u13 u18 age u9 midicontact u14 u19 (standard 15-man) u14 u19 (standard 15-man) fig. 2. female v. male development structures for 5 selected leading international rugby unions. incorporated ltad model stages: ‘fundamental’ (yellow), ‘learning to train’ (orange), ‘training to train’ (red), and ‘training to compete’ (purple). the new zealand and australian development models (grey) do not align with the balyi ltad model. the age groups at which competition occurs are indicated. a solid black line separating boys and girls indicates separate participation (no line indicates mixed-gender participation). refer to appendix i for online resources used to formulate this table. 34 sajsm vol. 25 no. 1 2013 • thereafter (u12 u19), a combination of standard 15-player rugby, sevens and modified/other non-contact formats (e.g. walla rugby) are adopted by the respective unions. practical guidelines women’s rugby in sa is not yet well structured. the primary objective of saru should be to establish participation or competitive structures across all the age groups from u6 to senior rugby. although the original balyi and hamilton[3] model proposes that males and females have separate ltad models, this review highlights that there is no scientific evidence supporting this proposed structure. saru is developing a detailed ltpd approach for male participation. there is no scientifically supported reason for a separate female ltpd model. the saru ltpd model should be applied to both males and females. conclusion there is no consistent participation in women’s rugby in sa across all the provincial unions. currently, in the majority of the provincial unions, participation structures revolve around the u16 interprovincial tournament organised by saru. less than half of the provincial unions (7/15; one union was subdivided; 47%) introduce rugby to young girls and only 20% (3/15; one union was subdivided) of the provincial unions have girls participating across all the junior age categories. there are currently no ltpd plans within any of the provincial unions. the original ltpd model separates males and females by chronological age and thus recommends gender-specific models. this original ltad model was based on physiological periods of theoretical enhanced adaptation (or windows of opportunity) of physical capacities. research has, however, shown that: (i) scientific data to support the presence of these periods (or windows) are lacking; and (ii) there is a dearth of scientific evidence to support the concept of different age separation of the ltpd stages for girls compared with boys. the practical implication is that there is no reason for a separate female ltpd model. the saru ltpd approach should be applied to both males and females. acknowledgements. this article was commissioned by the boksmart national rugby safety programme, implemented on behalf of saru and the chris burger/petro jackson players’ fund. the goal of the programme is to: teach safe and effective techniques; reduce the incidence and severity of injury; make the game safer for all involved; and improve rugby performance. this article also forms part of the evidence-based research in saru’s ltpd initiative driven by the game development division. the author thanks dr wayne viljoen, justin durandt and professor mike lambert for their input. references 1. balyi i, way r. long-term planning for athlete development: the training to train phase. canada: bc coach, 1995:2-10. 2. bompa t. from childhood to champion athlete. west sedona, az, usa: veritas publishing, 1995. 3. balyi i, hamilton a. long-term athlete development: trainability in children and adolescents. windows of opportunity. optimal trainability. victoria, bc: national coaching institute british columbia & advanced training and performance ltd, 2004. 4. higgs c, balyi i, way r, cardinal c, norris s, bluechardt m. developing physical literacy: a guide for parents of children aged 0 to 12. vancouver, bc: canadian sports centres, 2008. 5. rabinowicz t. the differentiated maturation of the cerebral cortex. in falkner f, tanner j, eds. human growth: a comprehensive 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[http://dx.doi.org/10.1080/17408990040106] 11. whithall j. development of locomotor co-ordination and control in children. in: savelsberg gjp, davids k, van der kamp j, eds. development of movement coordination in children: applications in the field of ergonomics, health sciences and sport. london: routledge, 2003:251-270. 12. butterfield sa, lehnhard r, lee j, coladarci t. growth rates in running speed and vertical jumping by boys and girls ages 11-13. percept mot skills 2004;99:225-234. 13. malina rm, bouchard c, bar-or o. growth, maturation and physical activity. champaign, il: human kinetics, 2004. 14. venturelli m, bishop d, pettene l. sprint training in preadolescent soccer players. int j sports physiol perform 2008;3:558-562. 15. fournier m, ricci j, taylor a, ferguson r, montpetit r, chaltman b. skeletal muscle adaptation in adolescent boys: sprint and endurance training and detraining. med sci sports exerc 1982;14:453-456. 16. cratty bj. perceptual motor development in infants and children. 3rd ed. englewood cliffs, nj: prentice-hall, 1986. 17. katch vl. physical conditioning of children. j adolesc health care 1983;3:241-246. [http://dx.doi.org/10.1010/50197-0070] 18. rowland tw. the “trigger hypothesis” for aerobic trainability: a 14-year follow-up (editorial). pediatr exerc sci 1997;9:1-9. 19. vrijens j. muscle development in the pre and post pubescent age. medicine in sport 1978;11:152-158. 20. weber g, kartodihardjo w, klissouras, v. growth and physical training with reference to heredity. journal of applied physiology 1976;40;211-215. 21. rowland tw. aerobic response to endurance training in prepubescent children: a critical analysis. med sci sports exerc 1985;17:493-497. 22. lillegard wa, brown ew, wilson dj, henderson r, lewis, e. efficacy of strength training in prepubescent males and females: effects of gender and maturity. paediatr rehab 1997;1:147-157. 23. pfeiffer r, francis r. effects of strength training on muscle development in prepubescent, pubescent and postpubescent males. phys sportsmed 1986;14:134143. http://dx.doi.org/10.1186/1479-5868-6-48] http://dx.doi.org/10.1186/1479-5868-6-48] http://dx.doi.org/10.1186/1479-5868-6-48] http://dx.doi.org/10.1186/1479-5868-6-48] http://dx.doi.org/10.1080/17408990040106] http://dx.doi.org/10.1010/50197-0070] sajsm vol. 25 no. 1 2013 35 appendix i online resources used to collate the data on the structure of the international rugby unions country resources (accessed 17 july 2012) australia australian rugby union • http://www.rugby.com.au/tryrugby/kidsrugby/kidspathway/2012kidspathwaymodifications.aspx • http://www.rugby.com.au/tryrugby/pathwaytogold/background.aspx • http://www.rugby.com.au/tryrugby/kidsrugby/kidspathway.aspx • http://www.rugby.com.au/tryrugby/playing/u13u19.aspx • http://www.rugby.com.au/tryrugby/playing/womens.aspx • http://www.rugby.com.au/linkclick.aspx?fileticket=f4pec-l2izu%3d&tabid=1595 • http://www.rugby.com.au/linkclick.aspx?fileticket=ybizkwsempq%3d&tabid=1595 canada rugby canada • http://www.rugbyalberta.com/clientuploads/coaching/rc_ltrd11.pdf england england rugby football union • http://www.rfu.com/takingpart/coach/coachresourcearchive/technicaljournalarchive/~/media/files/2009/ coaching/articles/technicaljournal/2005/1stquarter/ltad20booklet.ashx • http://www.rfu.com/~/media/files/2010/womensrugby/rfuw%20player%20pathway%201011.ashx • http://www.sussexrugby.co.uk/dyn/_assets/_pdfs/rfu-documnets-for-clubs/rfuw_law_guidance_card.pdf • http://www.rfu.com/~/media/files/2011/womensrugby/u13_girls_regulations_2011_2012.ashx • http://www.rfu.com/managingrugby/managingschoolsrugby/secondaryschools/teachingandlearning/ pelessonplans/tagtotackl ireland ireland rugby union • http://origin.irishrugby.ie/development/long-term_player_development.php • http://www.irishrugby.ie/downloads/game_variations_womens_rugby.pdf • http://www.irishrugby.ie/downloads/age_grade_regulation_variations_2011_to_2012.pdf new zealand new zealand rugby union (including small blacks) • http://files.allblacks.com/comms/strategies/nzru_womens_strategy_2012.pdf http://www.grammarjuniors.org. nz/resources/smallblackrugbyrules.pdf http://www.rugby.com.au/tryrugby/kidsrugby/kidspathway/2012kidspathwaymodifications.aspx http://www.rugby.com.au/tryrugby/pathwaytogold/background.aspx http://www.rugby.com.au/tryrugby/kidsrugby/kidspathway.aspx http://www.rugby.com.au/tryrugby/playing/u13u19.aspx http://www.rugby.com.au/tryrugby/playing/womens.aspx http://www.rugby.com.au/linkclick.aspx?fileticket=f4pec-l2izu%3d&tabid=1595 http://www.rugby.com.au/linkclick.aspx?fileticket=ybizkwsempq%3d&tabid=1595 http://www.rugbyalberta.com/clientuploads/coaching/rc_ltrd11.pdf http://www.rfu.com/takingpart/coach/coachresourcearchive/technicaljournalarchive/~/media/files/2009/ http://www.rfu.com/~/media/files/2010/womensrugby/rfuw%20player%20pathway%201011.ashx http://www.sussexrugby.co.uk/dyn/_assets/_pdfs/rfu-documnets-for-clubs/rfuw_law_guidance_card.pdf http://www.rfu.com/~/media/files/2011/womensrugby/u13_girls_regulations_2011_2012.ashx http://www.rfu.com/managingrugby/managingschoolsrugby/secondaryschools/teachingandlearning/ http://origin.irishrugby.ie/development/long-term_player_development.php http://www.irishrugby.ie/downloads/game_variations_womens_rugby.pdf http://www.irishrugby.ie/downloads/age_grade_regulation_variations_2011_to_2012.pdf http://files.allblacks.com/comms/strategies/nzru_womens_strategy_2012.pdf http://www.grammarjuniors.org sajsm 595 (commentarty).indd commentary 1 sajsm vol. 30 no. 1 2018 building a robust athlete in the south african high school sports system w lombard, mphil, bspsc (hons), cscs & rscc independent athletic performance specialist, co-founder la performance protea crescent west acres, nelspruit, 1201 corresponding author: w lombard (waynelombard@yahoo.com) schools are presently faced with important decisions on how best to structure their sports programmes to include the growing number of tournaments into their sports calendars. furthermore, school sports have become more professional and competitive, with the inclusion of the offer of cash prizes, as well as live tv coverage of these tournaments. thus the pressure on coaches to win at this level has increased significantly over the past 10 years. the intention of this article is not to disparage the south african school sport system but rather to create an understanding of best practice techniques when considering the conditioning practices related to high school athletes. as it has been the author’s experience through working with numerous high school athletes and presenting to various schools and educators on this topic, that the current system or lack thereof may not be athlete-centred. this may be in turn detrimental to their sporting development at a later stage [1]. thus in this author’s opinion, there is a definite need for a paradigm shift in school sports programming in south africa. as it currently stands, training is generally designed for short-term competitive performance rather than focusing on the optimal long-term development of a young athlete’s overall athletic capabilities [2]. with the growing volume of scientific literature in this area, it is important that this be made accessible to coaches and educators within the school system. thus the intention of this commentary is to disseminate the science of developing school sports and presenting it simply yet meaningful with a clear emphasis on its overall purpose. discussion starting with the end in mind it is evident that since the exclusion of physical education from the south african school curriculum, many young athletes entering high school lack the basic fine and gross motor skills that should be the norm at this age. therefore they often start high school with a low level of physical fitness and technical ability in sports [3]. therefore there is a need for a structured programme to address these issues and a new model of physical development is required which builds young robust athletes [2,4]. too often, young athletes are judged early on their performances during their school careers, rather than by their achievements after school. this approach may place undue pressure on the athlete to perform at a young age rather than putting in place the necessary characteristics required to sustain a high level of performance later on in their careers. schools may need to consider the fact that as a result of different rates of maturation schoolchildren need to be developed based on their future potential and not their current sporting performance [5]. the primary aim for a school’s sporting system should be to produce children who, when they are fully mature, will have the opportunity to pursue athletic achievement or lifelong recreational activity. however, the author is not implying that winning a tournament or match does not create a healthy competitive environment, but when winning is the focal point of a programme, it may be detrimental to the athlete’s overall sporting development. the increase of performance pressures in school sports has resulted in a well-documented growing trend of early specialisation and overtraining of the youth [6]. school athletes are often under pressure to complete multiple sessions per day in one sport or they are multi-sport athletes who are expected to complete a full practice and match load for two sports within the same season. it is here that coaches need to look after the best interests of the athlete in terms of training load (sport specific as well as strength and conditioning) and recovery. consequently, an emphasis should be placed on ensuring that the youth are exposed to various age appropriate structured technical activities (all sport specific and strength training related technical abilities). this should also include tactical (an understanding of the specific tactics within a sporting code) and physical training modalities as the exposure to a wide variety of stimuli at a young age allows for greater physiological adaptations as they progress through their careers. these will help to prepare them for the demands of their sporting activities and make them more robust and resilient to injuries [7]. however, in order to do this requires an acceptance from all stakeholders (teachers, coaches, parents, trainer as well as students) and careful monitoring of the athletes’ training loads and perception of wellness. creating an environment conducive to building a robust athlete one of the main benefits of any high school system is that all the students are under their guidance for a minimum of five years. this allows for the development of a sound five year background: school sport in south africa has become more competitive, and competition schedules are often found to be more congested. as a consequence young athletes are in an environment where they are exposed to high training and match demands. however, the school system generally fails to prepare these athletes physically to withstand the training and competition demands placed on them. discussion: it is important that schools implement a system that will allow their athletes to develop physically through ageappropriate strength and conditioning. it is especially important for schools to develop a plan to manage the multi-sport athlete in order reduce the risk of injury and burnout. by adopting a five year accumulative development model that fits the athlete’s environment, schools will contribute to the development of future professional athletes. key words: high school, student-athlete, multi-sport s afr j sports med 2018; 30:1-3.doi: 10.17159/2078-516x/2018/v30i1a2933 mailto:waynelombard@yahoo.com http://dx.doi.org/10.17159/2078-516x/2018/v30i1a2933 commentary sajsm vol. 30 no. 1 2018 2 model that will allow schools to create a student-centred approach when it comes to their sporting programmes. the multi-sport athlete when designing a longterm plan, it is the multisport athlete (playing two or more sports) that needs careful consideration. these athletes are generally found in the middle of a battle between coaches for each sport and are let down by an ego-driven system that lacks sufficient planning and collaboration between sporting codes. it is these athletes that are often taken advantage of by coaches and are caught in a dilemma on how to prioritise each sport. it is for this reason that a well thought-out, collaborative athlete-centred periodisation plan needs to be created. the plan should be designed so that it does not favour one particular sport but rather the development of the technical skills required by each sport and the fundamental physical qualities required to be a robust athlete [10]. a five year model figure 1 shows a schematic of a five year model that schools can implement to aid in the development of a robust high school athlete. within the model there are three distinct phases that should be emphasised, (1) development phase (grades 8 – 9), (2) transition phase (grade 10) and (3) competitive phase (grade 11 -12), with each phase leading into the other, thereby allowing for progressive overload and increasing complexity of training at each phase. although beyond the scope of this commentary, it is imperative that anyone who is drawing up such a plan, takes careful consideration of what exercises are implemented at each stage of the model [8]. they should stick to the basic principles of overload, progression and specific adaptions to imposed demands (saids) (please define this before using the acronym) of effective athletic development. fort-vanmeerhaeghe et al. propose an integrative neuromuscular training (int) model for youth athletes [4,7]. this model allows for the development of all fundamental physical qualities mentioned earlier for youth athletes and bodes well for training transfer into sports specific skills [4,7]. the following components should be included into the model at the three different stages mentioned earlier [4]; (1) dynamic stability (2) coordination (3) strength (4) plyometrics (5) speed / agility (6) fatigue resistant in order for this model to work is the education of coaches, teachers and parents on the benefits of strength and conditioning for youth athletes. many parents and coaches hold the incorrect perception that strength training is dangerous and may stunt the athlete’s growth. the scientific data show there is no evidence to support strength training stunting growth; however, it is essential that it is implemented under the guidance of a suitably qualified individual. in support of the early implementation of strength and conditioning programmes, evidence shows that the implementation of integrative neuromuscular training in youth athletes can reduce sports-related injuries to less than a third and overuse injuries by almost half [9]. researchers have also shown that by not implementing integrative neuromuscular training during the pre-adolescence and early puberty stages of development, the probability of the athlete reaching their full genetic potential or greater is far less than those who started at a young age [8]. conclusion from personal experience, it has been noticeable that most south african schools are without a long-term focused approach to developing robust high school athletes. the south african school system needs to implement an athlete-centred long-term strategy. the evidence is unequivocal, and the benefits far outweigh the negatives for the implementation of such a programme within the school system. the implementation of progressive integrative neuromuscular training from a young age will ensure that there is a reduction in the risk of injury and the production of robust athletes that are able to perform to their maximum potential with more enjoyment. references 1. durandt j, hendricks s, marshall m, et al. under-13 rugby: what are the issues? a panel discussion. s afrj sports med 2015;27(3):63-66. [doi:10.7196/sajsm.8078] 2. jeffreys i. quadrennial planning for the high school athlete. strength cond j 2008;30(3):74–83. [doi: 10.1519/ssc.0b013e3181775ae2] 3. uys m, bassett s, draper ce, et al. results from south africa's 2016 report card on physical activity for children and youth. j phys act health 2016;13(11 suppl 2):s265–73. [doi: 10.1123/jpah.2016-0409] 4. fort-vanmeerhaeghe a, romero-rodriguez d, montalvo am, et al. integrative neuromuscular training and injury prevention fig. 1. schematic of a five year model for schools commentary 3 sajsm vol. 30 no. 1 2018 in youth athletes. part i: identifying risk factors. strength cond j. 2016;38(3):36–48. [doi: 10.1519/ssc.0000000000000229] 5. lloyd rs, oliver jl, eds. strength and conditioning for young athletes: science and application. new york: routledge, pp.?. 6. jayanthi na, labella cr, fischer d, et al. sports-specialized intensive training and the risk of injury in young athletes: a clinical case-control study. am j sports med. 2015;43(4):794– 801. [doi: 10.1177/0363546514567298] 7. fort-vanmeerhaeghe a, romero-rodriguez d, lloyd rs, et al. integrative neuromuscular training in youth athletes. part ii: strategies to prevent injuries and improve performance. strength cond j 2016;38(4):9–27. [doi:10.1519/ssc.0000000000000234] 8. lloyd rs, cronin jb, faigenbaum ad, et al. national strength and conditioning association position statement on longterm athletic development. j strength cond res 2016;30(6):1491–1509. [doi: 10.1519/jsc.0000000000001387] 9. abernethy l, bleakley c. strategies to prevent injury in adolescent sport: a systematic review. br j sports med 2007;41(10):627–638. [doi: 10.1136/bjsm.2007.035691] 10. swanson jr. periodization for the multisport athlete. strength cond j 2004;26(4):50-58. original research 40 sajsm vol 23 no. 2 2011 introduction morbidity and mortality related to sedentary living are increasing worldwide. 1 in particular, coronary heart disease (chd), which is closely linked to risk factors such as obesity, insulin resistance, high blood pressure and abnormal blood lipid profiles, is increasing. traditionally women have been thought to be exempt from chd, especially pre-menopausal women. 2 it is now understood that the risk of developing hypercholesterolaemia and chd increases exponentially after menopause, and that it is vital for a woman’s cholesterol levels to be closely monitored. 3 two modalities of treatment exist for hypercholesterolaemia: drug intervention and lifestyle intervention. as drug interventions can have unpleasant physical side-effects as well as economic implications and issues of availability, it is important to establish the effect of lifestyle interventions on improving the blood lipid profile in individuals at risk for chd. while the impact of diet on plasma lipoproteins is fairly well established, 4 the effect of exercise is not as conclusive. 5,6 while it appears that aerobic endurance training may be an effective means of managing hypercholesterolaemia, 7-9 less is known about the effects of progressive resistance training. 10,11 in response to resistance training, hdl-cholesterol was reduced in women aged 54 71 years over 12 weeks. 12 further studies on samples including pre-menopausal women and men have either shown no change, 8,14,15 positive change 16 or, like joseph et al., 12 a negative response. there is very little literature has focused specifically on postmenopausal women. thus the problem addressed in this research was to establish the effect of a 24-week progressive resistance training programme on the blood lipid profiles of a sample of previously sedentary postmenopausal women. materials and methods study design a prospective, longitudinal (24 weeks) study design was employed on a cohort of postmenopausal women. the participants were required to attend thrice-weekly sessions of supervised resistance training which progressed from 50% of the pre-test 1-repetition maximum (1rm) effort intensity to 80% of the 1rm intensity over the course of the 24-week period. participant population twenty-six participants were recruited via information disseminated through local newspapers as well as flyers at local pharmacies and at general practitioners’ rooms. volunteers all agreed to participate in a protocol approved by the rhodes university, grahamstown, south africa ethics committee. participants were females aged 50 75 years. inclusion criteria were: postmenopausal (cessation of menses at least 12 months prior to selection for the study), sedentary (defined resistance training and changes to plasma lipoproteins in postmenopausal women correspondence: janet viljoen or candice christie department of human kinetics and ergonomics rhodes university po box 94 grahamstown, 6140 south africa tel +27 46 603 8470 fax +27 46 603 8934 email: c.christie@ru.ac.za janet.viljoen78@gmail.com janet erica viljoen (msc) candice jo-anne christie (phd) rhodes university, grahamstown, south africa abstract objectives. the main purpose of this study was to assess the effect of progressive resistance training on the blood lipid profile in postmenopausal women. methods. twenty-six female participants aged 50 75 years were selected from the population of grahamstown, south africa. all participants were previously sedentary and possessed at least one lipid profile abnormality but were otherwise healthy. pretests included a sub-maximal stress test, stature, mass, central and limb girths as well as an oral glucose tolerance test (ogtt) and a total blood lipid profile. participants took part in a 24-week progressive resistance training programme, consisting of three supervised sessions per week, each lasting 45 minutes. participants were not permitted to lose more than 10% of initial body mass during the 24-week study. all pre-test measures, excluding the stress test and the ogtt, were repeated every 4 weeks for the duration of the study. results. body mass, body mass index and waist-to-hip ratio did not change. girth measures at mid-humerus, chest, waist, hip, mid-quadricep and mid-gastrocnemius all decreased significantly (p<0.05). ldl-cholesterol increased significantly over the course of 24 weeks (3.61 mmol.l -1 to 4.07 mmol.l -1 ), as did total cholesterol (5.81 mmol.l -1 6.24 mmol.l -1 ). triglyceride concentration remained unchanged and hdl-cholesterol decreased significantly between the pre-test measure (1.55 mmol.l1 ) and the measure after 6 months (1.42 mmol.l -1 ). conclusion. the blood lipid profile in a sample of postmenopausal women was not positively affected by a progressive resistance training programme over a 24-week period. as less than three regular sessions of physical activity of 30 minutes’ duration per week for the previous 6 months, based on the american college of sports medicine’s recommendation that three sessions of exercise weekly, each of 30 minutes, is minimally beneficial to the individual), free from heart, lung, liver and kidney disease, not on hormone replacement therapy and non-diabetic or pre-diabetic. the latter was assessed through an oral glucose tolerance test (ogtt) conducted prior to the study, results of which were used specifically to screen for irregularities and were not included as part of the study thereafter. measurements clinical evaluation included a stress echocardiogram (ecg), resting blood pressure while standing, sitting and supine, and a full physical examination by a medical practitioner. a full ogtt was carried out at a reputable pathology laboratory. participants were required to fast from 22h00 the evening before the ogtt, and presented at the laboratory at 08h30. on arrival at the laboratory each participant was given a glucose solution to consume, mixed to specification (75 g of glucose mixed in water). a blood sample was taken within 2 minutes of consumption of the glucose drink and again 2 hours later. in between the two blood tests participants were permitted to leave the laboratory but were not permitted to eat or drink anything other than small amounts of water if required. anthropometric parameters included measures of stature, mass, and girth measures at the following anatomical sites: mid-humerus, chest over-bust, waist at the level of the umbilicus, hip, midquadricep and mid-gastrocnemius (table i). girth measures (upper arm, chest over-bust, waist, hip, thigh and calf) and mass (kg) were obtained by the principal researcher and were measured at the start of the same 60-minute exercise session on each occasion at 4-week intervals. two measurements were taken and if these matched the researcher was satisfied that the measurement was valid. the following anthropometric indicators were calculated: waist-to-hip ratio and body mass index (table i). full, fasting blood lipid profiles were obtained at a reputable pathology laboratory. blood was analysed using standard automated enzymatic processes on the dimension xpand plus clinical chemistry system. the following serum determinations were made from samples collected in the morning after a 12-hour fast: total cholesterol, high-density cholesterol (hdl-c) and triglycerides (enzymatic method) and low-density lipoprotein cholesterol (ldl-c) (estimation 16 ). for inclusion in the study, participants had to present with at least one lipid abnormality (total cholesterol higher than 5.20 mmol.l -1 ; ldl above 2.60 mmol.l -1 ; hdl above 1.30 mmol.l -1 or triglycerides above 1.70 mmol.l -1 ) and not present with an abnormal fasting blood glucose response. measurements were repeated every 4 weeks. training protocol a 24-week progressive resistance training (prt) programme was designed engaging the ‘find’ principle (frequency, intensity, nature and duration). in order to ensure reliability and validity of results intensity was tightly monitored throughout the study. initial intensity was set at 50% one-repetition-maximum (1-rm) and increased to 80% during the final phases of the project. the major muscle groups targeted are shown in table ii. participants were also required to attend three sessions per week for the 24-week study trial. although requested to maintain their habitual dietary intake for the duration of the study (and participants were regularly explained the reason as to why this was important), a limitation of the study is that diet was not monitored or controlled. this represents a weakness in the design of this study, of which the authors are aware. in executing this protocol the researcher intended to conduct a field study, replicating ordinary daily life so that the results might indicate the efficacy of lifestyle interventions in situ. in addition, this was a preliminary study for a further investigation, the design for which includes many improvements including better control of the participants’ dietary intake. the exercise programme was divided into six phases of 4 weeks’ duration (table iii). each phase represented an increase in intensity, initially by increasing the intensity from 50% of the 1-rm to 60% of the 1-rm, and then by increasing both the intensity and also the volume of repetitions and sets completed. table ii. exercises and musculature trained exercise major muscles engaged lateral pull-down latissimus dorsi, rhomboideus major, trapezius seated cable cow latissimus dorsi, trapezius, deltoid group, erector spinae, external oblique, rectus abdominus leg extension rectus femoris, vastus medialis, vastus lateralis, vastus intermedius chest press pectoralis major, deltoid group, external oblique, rectus abdominus, biceps brachii, triceps brachii abdominal crunches rectus abdominus, external oblique, internal oblique, transverse abdominus, iliopsoas, multifidus (activation of the core) hamstring curls semitendinosus, semimembranosus, biceps femoris step-ups rectus femoris, vastus medialis, vastus lateralis, vastus intermedius, semitendinosus, semimembranosus, biceps femoris, gastrocnemius, tibialis anterior table i. mean (±standard deviation) demographic data obtained from the participants n age (years) stature (m) mass (kg) bmi (kg.m -2 ) whr 26 56.77±4.12 1.63±60 79.08±17.42 29.8±6.77 0.85±0.08 bmi = body mass index; whr: waist-to-hip ratio. table iii. exercise programme design phase 1 2 3 4 5 6 intensity (%) 50 60 60 70 70 80 sets (no.) 1 1 2 2 3 3 repetitions (no.) 12 12 12 12 12 12 sajsm vol 23 no. 2 2011 41 42 sajsm vol 19 no. 4 200742 sajsm vol 23 no. 2 2011 exercise sessions were offered at times self-selected by the participants. each session was supervised by a research assistant (postgraduate students in the department of human kinetics and ergonomics, rhodes university, grahamstown). participants were required to attend three sessions weekly, each lasting 45 60 minutes. the aerobic warm-up comprised 10% of the session time, and the prt portion of the workout made up 90% of the session time. inclusion in data analyses was dependent on the participant completing 80% of the sessions (72 sessions in total). statistical analyses data are presented as mean ± standard deviation (sd). statistical significance was set at p≤0.05. a repeated measures one-way analysis of variance (anova) was employed to analyse the results, and statistical procedures were performed in statistica 8. 18 results compliance in order to be included in the data set participants had to attend at least 80% of the total number of sessions (72). of the initial sample (n=34) 87% completed 80% of the sessions and of this number, 9% attended 100% of the sessions. of the remaining participants 3% attended 70 75% of sessions, and 10% had only attended 50 60% of the 72 sessions. data from 26 participants were analysed once results had been corrected for compliance. anthropometric and girth measures body mass (kg) did not display significant changes (-0.77±0.62 kg) over the course of 24 weeks (p<0.05). waist circumference decreased significantly (p<0.05) from baseline to 4 weeks (-22±8 mm) (fig. 1). this measure, reflecting abdominal visceral fat (avf) deposits, continued to decrease significantly at 8 (-38±11 mm), 12 (-48±19 mm), 16 (-48±14 mm), 20 (-42±18 mm) and 24 weeks (-45±17 mm). hip girth reflected a similar pattern, also displaying significant decreases from week 8 (-36±9 mm) (p<0.05). weeks 12 (-35±9 mm), 16 (-39±9 mm), 20 (-40±9 mm) and 24 (-41±8 mm) were all significantly lower than the pre-test measure. upper extremity circumference showed significant decreases from week 8 (-10±3 mm) (fig. 1). this reduction continued at weeks 12 (-11±4 mm), 16 (-12±3 mm), 20 (-14±6 mm) and 24 (-14±6 mm). over-bust chest girth measure also showed a significant (p=0.05) decrease at week 8 (-23±14 mm) and this trend continued through weeks 12 (-35±15 mm), 16 (-39±11 mm), 20 (-32±18 mm) and 24 (-33±18 mm). mid-quadricep baseline measure (537±60 mm) decreased significantly at week 12 (-19±3 mm) (p<0.05). significant decreases were also recorded at weeks 16 (-25±3 mm), 20 (-33±11 mm) and 24 (-34±11 mm) (fig. 1). mid-gastrocnemius girth was significantly lower than the baseline measure at week 16 (-13±6 mm), 20 (-18±8 mm) and 24 (-18±8 mm) (p=0.05). plasma lipoproteins plasma lipoproteins measured by conventional methods reacted unexpectedly to the resistance training protocol. ldl increased significantly from baseline (3.61±0.78 mmol.l -1 ) to 4.07±0.81 mmol.l -1 (p<0.05) following the 24-week prt. while this is statistically significant it does not represent clinical significance, as the increase does not represent a ‘risk category’ increase. hdl decreased significantly at week 16 (-0.06±0.03 mmol.l -1 ) and continued to decrease at weeks 20 (-0.07±0.06 mmol.l -1 ) and 24 (-0.13±0.06 mmol.l -1 ). triglycerides increased significantly (p<0.05) at week 8 (0.31±0.32 mmol.l -1 ) but thereafter decreased in the next 12 weeks, returning to pre-intervention values at conclusion of the study (fig. 2). total cholesterol increased steadily in the first 12 weeks, reaching significantly higher than baseline values at weeks 16 (0.41±0.32 mmol.l -1 ), 20 (0.44±0.12 mmol.l -1 ) and 24 (0.43±0.15 mmol.l -1 ) (fig. 2). discussion this study evaluated the effect of progressive resistance training on the plasma lipoproteins in postmenopausal women. reliability of results required that the compliance of participants remained high. thus, only those participants who achieved at least 80% attendance at exercise sessions were included in the data analyses. furthermore, it was important for the outcomes of the study that the sample did not lose more than 10% of baseline body mass, as it has been demonstrated that weight loss positively influences plasma lipoprotein concentrations. 19,20 participants were instructed that loss of body mass greater than 10% would result in exclusion from the study and were requested not to attempt bodyweight loss. body mass in the current cohort did not change over the duration of the experiment. favourable changes in body composition can be expected as a result of resistance training, and in turn resting metabolic rate may increase. subsequent loss of fat weight, but increase in muscle weight may have occurred, and may represent a benefit of resistance training in this cohort. expectedly, bmi did not change significantly (29.80±6.77 kg.m -2 at baseline and 29.51±6.51 kg.m -2 fig. 1. mean girth measures                         * * * * * * fig. 1. mean girth measures. *significant difference to baseline measure multiple values significantly different to baseline measures quad = quadriceps muscle group gast = the gastrocnemius muscle fig. 2. plasma lipoprotein changes over the course of 24 weeks. *significant difference to baseline measure multiple values significantly different to baseline measure. 16 fig. 2. plasma lipoprotein changes over the course of 24 weeks. * significant difference to baseline measure multiple values significantly different to baseline measure. * * * * plasma lipoproteins m m o l.l -1 ldl hdl trig tc 0 4 8 12 16 20 24 after 24 weeks). other girth measures were positively affected by the exercise programme. in particular, reductions at central and distal anatomical sites with a concomitantly stable body mass reflected a decrease in fat mass and a possible increase in fat-free mass (given that body mass remained stable). this is in contrast to the findings of joseph et al., 12 who found that 12 weeks of resistance training reflected no change in body composition in postmenopausal women, while in their age-matched male participants, body fat was reduced. at 12 weeks in the current sample, all girth measures were positively responding (p<0.05) to the exercise programme. plasma ldl increased from as early as 4 weeks into the study (an increase of 0.17±0.36 mmol.l -1 compared with the pre-test baseline measure). this sharp increase leveled off at week 8 (0.02±0.17 mmol.l -1 ) but by week 12 ldl had increased by 6% relative to the baseline measure, and at week 24 ldl was significantly higher (12%) than pre-test. the changes in ldl cholesterol were not supported by recent literature, 12,21,22 which reported that resistance training in postmenopausal women resulted in no change to ldl levels. important to note however is that the current study was 24 weeks in duration with this time frame resulting in a significant increase in ldl. at 12 weeks ldl had also not significantly altered effectively, suggesting that had the studies of joseph et al,. 12 fahlmann et al. 21 and behall et al. 22 been continued for longer, they too may have seen an increase in ldl levels. furthermore, in the study by joseph et al. body composition was not altered, unlike in this study where body composition positively changed. hdl decreased significantly from baseline to 16 weeks (-3%) and 24 weeks (-8%), which is a finding supported by joseph et al. 12 in contrast to this it was found that resistance training had no effect on hdl concentrations in samples of middle-aged men. 23 triglyceride (tg) concentration reached a significant 20% (p<0.05) above the baseline value at week 8 (0.31±0.32 mmol.l -1 higher than the pre-test plasma triglyceride levels). over the following 16 weeks the plasma concentration of triglycerides appeared to decrease steadily, returning to pre-test levels at 24 weeks. similarly, in another study, no changes were found in triglyceride levels after 12 weeks of resistance training. 12 the drop and then subsequent increase in tg concentrations must be viewed within the context of the study design. tg levels are known to be influenced by many lifestyle-related factors such as dietary intake, alcohol consumption, smoking and menstrual status, to name a few. 4 while smoking and menstrual status were controlled for in this study, no controls were instituted for alcohol intake, dietary or any other lifestyle habits. the drop in tg after 8 weeks therefore could have been a consequence of subconscious (or possibly even conscious) altered habitual lifestyle as it is well known that when individuals start exercising, diet is often changed subconsciously and individuals tend to start living a healthier lifestyle. 6 motivation for healthier lifestyle habits may have reduced over time and hence the increase in tg levels back to baseline may, again, be due to poorer lifestyle choices outside of the exercise influence. interestingly however is the fact that although body fat was not measured, it was postulated that there was a decrease in fat mass and an increase in lbm as reflected by the changes in girth measures. evidence suggests that this should positively alter tg concentration 13 and yet this was not the case. either body composition was not altered due to the exercise intervention or the other lifestyle choices made by the participants could have negated the positive body composition effect. the latter is the more plausible. total cholesterol (tc) increased significantly (p<0.05) by week 16 (an increase of 7%) and was significantly elevated from baseline at both 20 and 24 weeks, which is in contrast to previous findings. 14 despite this significant change, it is important to note the clinical significance of these findings as at 24 weeks, the increase from baseline was only 0.43±0.15 mmol.l -1 . current recommended levels of the plasma lipoproteins are hdl ˃ 0.90 mmol.l -1 , ldl ≤3.00 mmol.l -1 (but ≤1.50 mmol.l -1 for those with known cardiac risk), triglycerides <1.70 mmol.l -1 and tc ≤5.00 mmol.l -1 . 27 the current sample fell within the ‘borderline’ category prior to the exercise intervention for ldl (3.61 mmol.l -1 ) and tc (5.81 mmol.l -1 ), and within the desirable range for both hdl (1.55 mmol.l-1) and triglyceride concentration (1.54 mmol.l -1 ). following the training intervention these values had shown statistically significant changes (p<0.05), but did not show clinically significant permutations. ldl remained within the ‘borderline’ category (4.07 mmol.l -1 at 24 weeks), hdl remained at desirable levels (1.42 mmol.l -1 ) and tc was still below 7.50 mmol.l -1 , which is the upper limit of the ‘borderline risk’ category (6.24 mmol.l -1 at 24 weeks). tg concentrations above 2.26 mmol.l -1 would reflect hypertriglyceridaemia, 27 but the tg concentrations for the current sample remained below this margin (1.54 mmol.l1 prior to the intervention and 1.65 mmol.l -1 at 24 weeks). conclusion although these findings suggest a negative lipoprotein response to resistance training in postmenopausal women, the findings should be interpreted within the context of the study design and in the light of clinical significance. this especially in light of the fact that dietary intake was not strictly controlled or monitored and that there was no comparative control group. future studies should consider these factors. the large variation in results obtained indicates that a mechanism for positive change exists and requires a more strictly controlled study to become clearly evident. acknowledgements the authors would like to acknowledge the contributions of dr celia p jameson, specialist physician, for the health screening of the participants and professor sarah radloff, department of mathematical statistics, rhodes university, for assistance with the statistical procedures. the authors would further like to thank the 2008 postgraduate students from the department of human kinetics and ergonomics at rhodes university who assisted with supervision of the exercise sessions. competing interests all authors declare that the answer to the questions on your competing interest form are all no and therefore have nothing to declare. funding funding for this research project was provided by the joint research council at rhodes university. references 1. chakravarthy mv, booth fw. eating, exercise and the “thrifty” genotypes: connecting the dots toward an evolutionary understanding of modern chronic disease. j appl physiol 2000;96:3-10. 2. skouby so. health in the menopause: advances in management. intern congr ser 2004;1266:151-155. 3. jensen j. lipids and lipoprotein profile in postmenopausal women. dan med bull 1992; 39:64-80. 4. haskell wl. cardiovascular disease prevention and lifestyle interventions: effectiveness and efficacy. j cardiovasc nurs 2003;18:245-255. 5. halverstadt a, phares da, wilund kr, goldberg ap, hagberg jm. endurance exercise training raises high density lipoprotein cholesterol and lowers small low density lipoprotein and very-low density lipoprotein independent of body fat phenotypes in older men and women. metabolism 2007;56:444-450. sajsm vol 23 no. 2 2011 43 6. trejo-gutierrez j and fletcher g. impact of exercise on blood lipids and lipoproteins. j clin lipidol 2007;1:175-181. 7. king ac, haskell wl, young dr, oka rk, stefanick ml. long-term effects of varying intensities and formats of physical activity on participation rates, fitness and lipoproteins in men and women aged 50 to 65 years. circulation 1995;91:2596-2604. 8. kokkinos pf, holland jc, pittaras ae, narayan p, dotson co, papademetriou v. cardio-respiratory fitness and coronary heart disease risk factor association in women. j am coll cardiol 1995;26:358-364. 9. spate-douglas t, keyser re. exercise intensity: its effect on the high density lipoprotein profile. arch phys med rehab 1999;80:691-695. 10. nicklas bj, katzel li, busby-whitehead j, goldberg ap. increases in high-density lipoprotein cholesterol with endurance exercise training are blunted in obese compared with lean men. metabolism 1997;46:556-561. 11. thompson pd, yugalevitch sm, flynn mm, et al. effect of prolonged exercise training without weight loss on high-density lipoprotein metabolism in overweight men. metabolism 1997;46:217-223. 12. joseph ljo, davey sl, evans wj, campbell ww. differential effect of resistance training on the body composition and lipoprotein-lipid profile in older men and women. metabolism 1999;48:1474-1480. 13. comizio r, pietrobelli a, tan xy, et al. total body lipid and triglyceride response to energy deficit: relevance to body composition models. ajp endo 1998;274(5):e860-e866. 14. elliott kj, sale c, and cable nt. effects of resistance training and detraining on muscle strength and blood lipid profiles in postmenopausal women. br j sports med 2002;36:340-344. 15. lemura lm, von duvillard sp, andreacci j, klebez jm, chelland sa, russo j. lipid and lipoprotein profiles, cardiovascular fitness, body composition and diet during and after resistance, aerobic and combination training in young women. eur j appl physiol 2000;82:451-458. 16. wallace mb, mils bd, browning cl. effects of cross-training on markers of insulin resistance/hyperinsulinaemia. med sci sport exerc 1997;29:1170-1175. 17. friedewald wt, levy ri, fredrickson ds. estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. clin chem 1972;18:499-502. 18. statsoft, inc. statistica 2007. version 8.1 (www.statsoft.com) 19. martini c, pallottini v, de marinis e, et al. omega-3 as well as caloric restriction prevent the age-related modifications of cholesterol metabolism. mechanisms of aging and development 2008;129:722-727. 20. volek js, fernandez ml, fernman rd, phinney sd. dietary carbohydrate restriction induces a unique metabolic state positively affecting atherogenic dyslipidaemia, fatty acid partitioning, and metabolic syndrome. prog lipid res 2008;47:307-318. 21. fahlmann mm, boardley d, lambert cp, flynn mg. effects of endurance training and resistance training on plasma lipoprotein profiles in elderly women. journals of gerontology a: biological sciences and medical sciences 2002;57:b54-60. 22. behall km, howe jc, martel g. comparison of resistive to aerobic exercise training on cardiovascular risk factors of sedentary, overweight, premenopausal and postmenopausal women. nutr res 2003;23:607-619. 23. smutok ma, reece l, kokkinos pf, et al. aerobic versus strength training for risk factor intervention in middle aged men at high risk for coronary heart disease. metabolism 1993;42:177-184. 24. mcardle wd, katch fi, katch vl. exercise physiology: energy, nutrition and human performanc,. 4th ed. 1996. baltimore: williams and wilkins. 25. hodgetts v, coppack sw, frayn kn, hockaday tdr. factors controlling fat mobilization from human subcutaneous adipose tissue during exercise. am physiol soc 1991;71:445-451. 26. brooks ga, mercier j. balance of carbohydrate and lipid utilization during exercise: the “crossover” concept. am physiol soc 1994;76:2253-2296. 27. eberly le, stamler j, neaton jd. relation of triglyceride levels, fasting and non-fasting, to fatal and non-fatal cardiovascular heart disease. arch intern med 2003;163:1077-1083. 44 sajsm vol 23 no. 2 2011 sajsm vol. 24 no. 3 2012 81 original research playing time between senior rugby players of different ethnic groups across all levels of south african rugby, 20072011 jacques du toit, justin durandt, jonathan joshua, herman masimla, mike lambert discovery high performance centre, sports science institute of south africa, and mrc/uct research unit for exercise science and sports medicine, faculty of health sciences, university of cape town jacques du toit, ba (hons) biokinetics justin durandt, bsc (med hon) exercise science (biokinetics) jonathan joshua, bsc (med hon) exercise science (biokinetics) mike lambert, phd south african rugby union herman masimla, ba, hde corresponding author: jacques du toit (jdtoit@ssisa.com) introduction following the formation of a single body to govern rugby in south africa in 1992, the south african rugby union (saru) has had a continual challenge to make the game fully representative at all levels, particularly since most representative teams at all levels were dominated by white players.1,2 politicians have accused saru of being resistant to change despite saru’s attempt to transform the game by launching several programmes designed to promote the development of black and coloured players from previously disadvantaged areas.3 for example, the ‘nike all stars’ programme ran from 1999 to 2002 and focused on the talent identification of youth (12 15 years). the players identified by this programme were invited to attend various provincial trials and training camps spanning the 4-year period of the programme. for many players these camps were their first exposure to the demands and expectations of a professional athlete. players were exposed to physiological testing, nutritional advice, life skills and technical rugby coaching. the ‘spoornet rugby excellence’ programme had a similar structure to the ‘nike all stars’ programme and ran for a 5-year period from 1998 to 2002. this programme focused on players of all ages, including senior players. players from across the country were identified and invited to various camps that focused on equipping players with the skills needed to play rugby at a higher level. the players had a full medical evaluation, followed by any appropriate medical intervention they needed. their physiological characteristics were profiled and players received customised training programmes and access to strength-training facilities. training camps were held throughout the year to facilitate the continual development of the players participating in the programme. in addition players received personalised interventions including accommodation, transport and educational grants where required. the programme aimed to be comprehensive and facilitate the development of the players in the senior ranks. in 2002 saru introduced high-performance workshops at the u18 craven week. a study at this craven week showed that black and coloured players weighed about 8 kg less than their white counterparts.4 this study also showed that most of these players did not have access to weight training equipment. in response to these findings saru and the sports science institute of south africa background. the south african rugby union (saru) has had a continual challenge to make the game representative of players of all ethnic groups at all levels of play. in response to this challenge saru has implemented several programmes designed to accelerate the development of players from previously disadvantaged areas with the goal of making the game more representative. however, the success of these programmes to transform the player profile at different levels of rugby cannot be evaluated because the players representing different ethnic groups have not been quantified in a systematic way. objectives. to quantify the number and playing time of south african professional players (vodacom, currie cup, super rugby and springboks) from different ethnic groups from 2007 to 2011 to determine whether there are any changes in the profile of the players over this period. methods. playing time was recorded for all players in sanctioned matches. players were divided into the ethnic classifications used by saru (i.e. white, coloured and black). results. at all levels of competition there were proportionally more white players, followed by coloured players and then black players. this pattern did not change from 2007 to 2011. based on the ratio of number of players v. playing time, the white players played more time than expected at the springbok level, whereas the black players played less than expected for the number of players from 2007 to 2011. at the vodacom level the white players played more than expected in 2007 and 2008 and played less than expected in 2010 and 2011, whereas the black players played more than expected in 2010 and the coloured players played more than expected at the 2011 tournament. the super rugby tournament had the most consistency between players and expected playing time for the different ethnic groups. conclusions. despite the effort to support players from disadvantaged backgrounds since 1998 with facilitative programmes and selection targets, the professional game is still dominated by white players at all levels. s afr j sm 2012;24(3):81-86. doi:10.7196/sajsm.327 82 sajsm vol. 24 no. 3 2012 developed and launched the mobile team training system (mtts) in 2003. the mtts is a shipping container that has been modified and refurbished with high-quality strength-training equipment, so that an entire team can train simultaneously. the mtts container can be transported to remote areas within the country and provide high quality training facilities to the teams that previously did not have access to equipment. by the middle of 2011, saru had distributed 32 mtts units across the country. coinciding with the delivery of the mtts to a region, saru organises a strength-training workshop for all coaches and trainers in the region and also provides on-going monitoring and support. in 2003 the green squads were also introduced with the goal of developing talent. this was a broad-based talent identification programme designed to serve the needs of the provinces and national teams. the green squad comprised five age groups, each with ±100 players, representing players in the under-16, -17, -18, -19 and -20 age groups. players were selected, based on their rugby skills, by a national panel of selectors. national scouts also provided input for selection. once the players in each of the age groups were selected, they were subjected to 3 assessment sessions for the year. these sessions consisted of physical tests, skills tests and nutritional assessments. players were given feedback on their performance in each of the 3 assessment areas. in 2006 the high-performance workshops were expanded to the academy week (national u18 week) and grant khomo week (national u16 week). in 2007 saru launched the elite squad project, which replaced the old green squads. saru had found that players from disadvantaged areas were still experiencing challenges in terms of their nutrition, supplements and conditioning and the aim of this new programme was to bridge the gap between the age group players in the country by providing testing equipment, supplements and money for all the unions. this programme ran for 3 years. in addition to these programmes saru has placed further emphasis on transformation by having quotas for ‘players of colour’ (which is a saru euphemism for black and coloured players) at both junior and senior levels. for example, in the 2010 craven week (national u18 week) teams were to be selected with a ratio of 13 white players to 9 players of colour, while the academy week and grant khomo week teams were to be selected with a ratio of 11 white players to 11 players of colour.5 most recently, the 2011 varsity cup (university rugby competition) had regulations which required for the playing squad of 23 players to contain 5 players of colour while 3 players of colour had to be on the field at all times.6 despite the various saru programmes which have been established to address transformation, and the implementation of quota policies in selection, there is still concern that the effects of these attempts to transform the game are not filtering through to the higher senior levels of the game. these concerns cannot be quantified because there are no hard data against which the effects of these programmes can be measured. this is coupled with the confusion about having a measurable definition of ‘transformation’. a meeting between all provincial presidents in 2006 highlighted the shortcomings of defining transformation through the simplistic view of just counting heads of players.7 we propose that an alternative and better way of defining and monitoring transformation is to report the total playing time of players in a season. this approach would circumvent the problem of having ‘token’ players in the team who were selected to merely make up numbers so the team could conform to the required demographics. such players would not contribute much to the playing team and mask the transformation of players. this approach of quantifying transformation programmes is in alignment with the national sports plan (p. 56 57)8 with which all sporting governing bodies are expected to comply and the targeted performance dimensions contained in the transformation charter for south african sport (appendix a – dimension 3, p. 44).9 therefore the aim of the study was to quantify playing time of the senior players at different levels (vodacom, currie cup, super rugby and springboks) from 2007 to 2011 to determine firstly whether there are differences between the proportions of white, coloured and black players, and secondly whether there have been changes in these values over this period. it would have been helpful to include national and provincial age group teams. however, these data were not available, hence the analysis was limited to senior players. methods the playing time of all professional rugby union players in south africa during the 2007, 2008, 2009, 2010 and 2011 seasons was tabulated. playing time was defined as the total minutes played by a professional rugby union player during a sanctioned competitive match excluding friendly matches. therefore playing time was recorded for all players involved in springbok test matches, super rugby competitive matches, absa currie cup matches and vodacom cup matches during these five seasons. the players were divided into racial populations based on the same classification system used by saru, i.e. white, black or coloured. the player’s racial information was obtained through either the saru official website (www.sarugby.co.za) or by directly contacting the union that the player was contracted to. the playing time of each individual player for that match was obtained on the saru official website. the playing time was determined by the total time the player spent on the field of play. red and yellow cards, tactical substitutions and blood injury substitutions were considered in the calculations. if a player was part of the 22man playing squad, but did not play during the match, he was not credited with any playing time. the maximum playing time a player could accumulate for a single match was limited to 80 minutes. in the event of a knockout match resulting in a tie, additional halves would be played and this additional time would be added onto the overall playing time. the data for each match were checked for arithmetical accuracy (i.e. the total time for each match had to equal 1 200 minutes per team unless a player received a yellow, red card or additional halves being played). results the total number of players per season in the different competitive levels for the seasons 2007 2011 is shown in table 1. in all cases (competition v. year) there were proportionally more white players, followed by coloured and black players. there were no noteworthy changes in representation (i.e. player number) over the 5 years. table 2 shows the total playing time for the season for each ethnic group (2007 2011). similarly, the total playing time of the white players was higher than that of the coloured and black players and there were no obvious trends over the years. in fig. 1 the total number of players (expressed as a percentage of the overall total on the x axis) is plotted against the total playing time (expressed as a percentage of the total playing time on the y axis) for 2007 2011. when the data point lies on the line of unity it may be sajsm vol. 24 no. 3 2012 83 assumed that the number of players are represented appropriately in terms of expected playing time. when the data point is below the line of unity it suggests that according to the total number of players, there is an under-representation in terms of playing time (i.e. this would represent a scenario where players are selected to meet quotas). in contrast, if the data point lies above the line, then the players are playing more than expected (to compensate for players in the team who are playing less than expected). using this logic the data are table 1. the number and (%) of white, coloured and black rugby players for the springboks, super rugby, currie cup and vodacom teams, 2007 2011 2007 2008 2009 2010 2011 springboks whites 36 (77%) 26 (65%) 32 (67%) 35 (70%) 31 (72%) coloured 9 (19%) 7 (18%) 11 (23%) 10 (20%) 8 (19%) blacks 2 (4%) 7 (18%) 5 (10%) 5 (10%) 4 (9%) total 47 40 48 50 43 super rugby whites 126 (81%) 123 (78%) 125 (79%) 138 (80%) 136 (82%) coloured 23 (15%) 22 (14%) 22 (14%) 20 (12%) 21 (13%) blacks 7 (4%) 12 (8%) 12 (8%) 14 (8%) 9 (5%) total 156 157 159 172 166 currie cup whites 371 (72%) 373 (70%) 363 (71%) 371 (74%) 375 (74%) coloured 90 (18%) 101 (19%) 84 (17%) 72 (14%) 80 (16%) blacks 51 (10%) 56 (11%) 62 (12%) 58 (12%) 52 (10%) total 512 530 509 501 507 vodacom whites 323 (70%) 313 (65%) 323 (70%) 348 (71%) 381 (73%) coloured 82 (18%) 109 (23%) 85 (18%) 85 (17%) 84 (16%) blacks 55 (12%) 57 (12%) 56 (12%) 59 (12%) 59 (11%) total 460 479 464 492 524 totals may not be 100% as a result of rounding percentages. table 2. total playing time (minutes) and (%) of white, coloured and black rugby players for the springboks, super rugby, currie cup and vodacom teams, 2007 2011 2007 2008 2009 2010 2011 springboks whites 13 504 (82%) 9 967 (64%) 12 256 (73%) 12 666 (71%) 8 321 (77%) coloured 2 833 (17%) 3 965 (26%) 2 861 (17%) 4 361 (24%) 1 863 (17%) blacks 212 (1%) 1 627 (11%) 1 596 (10%) 924 (5%) 572 (5%) total 16 549 15 559 16713 17951 10 756 super rugby whites 6 7297 (82%) 60 217 (78%) 61 616 (77%) 65 685 (82%) 78 773 (81%) coloured 11 781 (14%) 10 325(13%) 10 427 (13%) 9 242 (12%) 13 483 (14%) blacks 2 759 (3%) 6 484 (8%) 8 256 (10%) 5 300 (7%) 5 572 (6%) total 81 837 77 026 80 299 80 227 97 828 currie cup whites 160 039 (76%) 162 578 (72%) 152 614 (71%) 157 972 (76%) 168 912 (77%) coloured 33 255 (16%) 40 660 (18%) 37 885 (18%) 30 252 (15%) 30 745 (14%) blacks 17 689 (8%) 21 602 (10%) 23 370 (11%) 18 515 (9%) 18 607 (9%) total 210 983 224 840 213 869 206 739 218 264 vodacom whites 87 936 (74%) 87 977 (67%) 80 421 (69%) 92 043 (69%) 101 568 (71%) coloured 17 613 (15%) 29 506 (22%) 21 456 (19%) 22 595 (17%) 25 832 (18%) blacks 12 813 (11%) 14 730 (11%) 14 038 (12%) 17 971 (14%) 16 047 (11%) total 118 362 132 213 115 915 132 609 143 447 totals may not be 100% as a result of rounding percentages. 84 sajsm vol. 24 no. 3 2012 summarised in table 3, showing whether there was overplaying (↑), underplaying (↓) or expected playing time for the number of players (≈). a margin of error of 1% was accepted in the interpretation. out of the 60 possible situations (5 years x 12 categories per year), there were 30 situations (50%) where the playing time matched the number of players (≈) (table 3). in 25% of the cases the players were over-represented and in 25% of the cases they were under-represented. there were no obvious trends over time. based on the ratio of number of players v. playing time, at the springbok level the white players played more times than expected whereas the black players played less than expected for the number of players from 2007 to 2011. at the vodacom level the white players played more than expected in 2007 and 2008 and played less than expected in 2010 and 2011, whereas the black players played more than expected in 2010 and the coloured players played more than expected at the 2011 tournament. the super rugby tournament had the most consistency between players and playing time for the different ethnic groups. across all tournaments and years the white players were over-presented 17% of the cases, the coloured players 5% of the cases and the black players 3% of the cases. in a similar comparison of under-presentation the white players were under-represented 5% of the time whereas the coloured and black players were both under-represented in 10% of the cases. discussion the first finding of this study was that there were major differences in playing times of the senior players at all four levels of play (vodacom, currie cup, super rugby and springboks). in many cases the white players played more than expected based on their numbers, compared with the coloured and black players. the only times the white players played less than expected, based on their numbers, was at the vodacom level and once at the super 14 level (2009). the next finding was that there were no clear changes in the patterns of the proportions of white, coloured and black players from 2007 2011, at all levels of competition with the white players continuing to be dominant followed by coloured and then black players. these data show that the numerous specialised programmes that saru have implemented since 1998 have not had the desired effects of transforming the game. the way in which these results are interpreted needs to be carefully considered. there is the temptation to immediately conclude that the lack of transformation is due to the type of programmes that have been offered, or the way they have been implemented. one should however consider the complexity of high-performance sport and the factors that influence it prior to making any conclusions. digel (2002) describes how worldclass performance in any country is dependent on three pillars: ‘the first one is society, in general, as a resource for the elite sport system. the second is the sporting system itself. the third pillar is the environment of the specific sports system as defining factor for world class performance’.10 this suggests that it is clear that there are other hurdles that need to be overcome before the effects of the specialised programmes can be realised. for example, a recent study of over 10 000 south african schoolchildren (6 13 years) showed that there were significant differences in fitness scores and morphology of children of different ethnic origins, with the white children generally being bigger and scoring higher in the fitness tests than the coloured and black children.11 these differences were largely eliminated when socio-economic status was controlled. talent needs to be developed in a structured way, starting at a young age and progressing with maturity.12 therefore it is obvious that children starting off compromised, because of being raised in a low socioeconomic environment, will always have a competitive disadvantage as they grow and mature.13 junior player development pathways in rugby, as implemented by australia and new zealand, recognise the importance of specific development at various ages for success in the game.14 these models emphasise the importance of creating an environment where children (6 12 years of age) have the ability to develop the various characteristics critical to sports performance.15 it follows that community clubs and schools need to follow a development model across all socioeconomic groups that allow for optimum development at a young age and reduce the developmental difference between ethnic groups, as they get older. every stage of development has different factors that contribute to the skill acquisition that is required by a high-level adult player. one of the key factors in south african rugby is the alignment and cooperation between the different organisations in which the game is played, such as schools, clubs, universities and provincial unions. all saru’s efforts at development may be ineffective if the work of these different organisations is not aligned. furthermore, the departments of sport, education and health also have an important contribution to ensure that the disparities arising from differences in socioeconomic status and facilities are reduced. conclusion in summary, the data from this study suggest that the specialised programmes designed to accelerate transformation by creating an enabling environment, are not having the desired effect. we have table 3. summary showing whether players had the expected playing time (≈), overplayed (↑), or underplayed (↓) in the springbok, super rugby, currie cup and vodacom cup (2007 2010) springboks super rugby currie cup vodacom w c b w c b w c b w c b 2007 ↑ ↓ ↓ ≈ ≈ ≈ ↑ ↓ ↓ ↑ ↓ ≈ 2008 ≈ ↑ ↓ ≈ ≈ ≈ ↑ ≈ ≈ ↑ ≈ ≈ 2009 ↑ ↓ ≈ ↓ ≈ ↑ ≈ ≈ ≈ ≈ ≈ ≈ 2010 ≈ ↑ ↓ ↑ ≈ ≈ ↑ ≈ ↓ ↓ ≈ ↑ 2011 ↑ ↓ ↓ ≈ ≈ ≈ ↑ ↓ ≈ ↓ ↑ ≈ w = white; c = coloured; b = black. sajsm vol. 24 no. 3 2012 85 fig. 1. total number of players in each ethnic group expressed as a percentage of the number for that group v. the total playing time expressed as a percentage. 86 sajsm vol. 24 no. 3 2012 highlighted the complex nature of transforming a sport which functions in the context of broader society and its structures. an example of a factor that will need to be addressed to improve the effectiveness of specialised programmes for youth and young adults is the disparity in body size and fitness of young children. this emphasises the importance of the different organs of society such as the state and sports organisations working closely together to ensure both high levels of participation and excellence. until the fundamental inequalities in society are reduced, the specialised programmes designed to accelerate transformation are unlikely to achieve their desired outcome. finally, playing time should be collected on an on-going basis so that efficacy of the transformation projects within south african rugby can be measured. this approach is in accordance with the broader international debate regarding evidence-based policy making and practice in international sporting policies.16 references 1. heath d, grieb e. sa rugby annual. 40th ed. cape town: saru & mwp (pty) ltd; 2011. 2. sulaiman s. transformation policy for south african rugby: comparative perceptions. cape peninsula university of technology theses and dissertations, 2006: 229. 3. harmse j. currie cup too white absa. 17-9-2010. http://www.sport24.co.za/ rugby/ currie-cup-too-white-absa-20100917 (accessed 20 june 2011). 4. durandt j. coca-cola craven week project. internal report to sa rugby, 12 august 2002. 5. south african schools rugby association. executive meeting of the south african schools rugby association, 19 february 2010. 6. varsity cup competion rules 2011. http:// www.varsitycup.co.za/index.php?option =com_content&view=article&id=3258 (accessed 20 june 2011). 7. meeting minutes between sa rugby and provincial rugby presidents, 29 june 2006. 8. south african sport and recreation, 2012; national sport and recreation plan, 1-77, www.info.gov.za/view/downloadfileaction?id=154620 (accessed 25 june 2012). 9. south african sport and recreation, 2012; transformation charter for south african sport, 1-52, www.srsa.gov.za/medialib/home/documentlibrary/ transformation%20 charter%20-%20final%20feb%202012.pdf (accessed 25 june 2012) 10. digel h. the context of talent identification and promotion: a comparison of nations. new studies in athletics 2002;17:13-26. 11. armstrong meg, lambert ev, lambert mi. physical fitness of south african primary school children, 6 to 13 years of age: discovery vitality health of the nation study. perceptual and motor skills, 2011;113(3):999-1016. [http://dx.doi. org/10.2466%2f06.10.13.pms.113.6.999-1016] 12. vaeyens r, lenoir m, williams am, philippaerts rm. talent identification and development programmes in sport: current models and future directions. sports med 2008;22(10):67-68. 13. figueiredo aj, goncalves ce, coelho e silva mj, malina rm. characteristics of youth soccer players who drop out, persist or move up. j sports sci 2009;27(9):883-891. [http://dx.doi.org/10.1080%2f02640410902946469] 14. lambert mi, durandt j. long-term player development in rugby – how are we doing in south africa? s afr j sports med 2010;22(10):67-68. 15. bailey rp, collins d, ford pa, mcnamara á, pearce g, toms m. participant development in sport: an academic literature review. leeds: sports coach uk. commissioned report for sports coach uk 2010;1-134. 16. coalter f.  a wider social role for sport: who’s keeping the score? london: routledge, 2007. commentary 136 sajsm vol 23 no. 4 2011 introduction presentations delivered at the 14th biennial south african sports medicine congress in johannesburg (18 20 october 2011) indicate that the south african sports medicine association (sasma) not only met, but exceeded expectations related to the conference theme ‘from basics to brilliance – world class in africa’. in my opinion (a visiting american scholar) sasma demonstrated commitment to high-quality sports injury prevention, treatment, rehabilitation and management. more specifically, a significant step was taken towards embracing exercise is medicine® (eim), with an appeal to all sports medicine and allied health practitioners to expand the scope of public health intervention strategies. 1,2 consequently, the purpose of this commentary is to: ● alert readers to the global burden of unintentional and intentional injury ● advocate a greater public health injury prevention role for sports medicine and related allied health practitioners. worldwide injury burden according to the world health organization (who, 2010) violence and injury prevention unit: ‘injuries kill about 5.8 million people each year. this accounts for 10% of the world’s deaths, 32% more than fatalities from malaria, tuberculosis and hiv/aids combined. tens of millions more suffer injuries that lead to hospitalization, emergency treatment or other care. among the causes of injury are acts of violence against others or oneself, road traffic crashes, burns, drowning, falls and poisoning. nearly one third of the 5.8 million deaths from injuries are the result of violence suicide, homicide and war and nearly one quarter are the result of road traffic crashes.’ (see fig. 1. 3 ) ‘injuries are a growing problem. globally, the three leading causes of death from injuries are all predicted to rise in rank compared to other causes of death. road traffic crashes are predicted to become the fifth leading cause of death by 2030, with suicide and homicide rising to become the 12th and 18th leading causes of death respectively. injuries affect all age groups but have a particular impact on young people. for people between the ages of 5 and 44 years, injuries are one of the top three causes of death.’ 3 given that injuries are a leading cause of death among young people, when combined, unintentional and intentional injury are a leading cause of years of potential life lost under age 65, ahead of coronary heart disease and cancer. 4 deaths represent only the tip of the iceberg: ‘deaths that result from injuries represent only a small fraction of those injured. millions of people suffer injuries that lead to hospitalization, emergency department or general practitioner treatment, or treatment that does not involve formal medical care. the consequences of injuries and violence are significant …. leading to physical injuries, mental consequences (depression, anxiety), behavioural changes (smoking, alcohol and drug misuse, unsafe sexual practices, unwanted pregnancies); leading to death, disability, suicide, hiv and other stds, cancer, cardio-vascular and other noncommunicable diseases.’ 3 almost twice as many men as women die as a result of injuries and violence each year. 3 for men the three leading causes of death from injuries are road traffic injuries, suicide and homicide, while leading causes for women are road traffic injuries, suicide, and firerelated burns. 3 for each type of injury (except injury resulting from fires), death rates are higher for men than for women. 3 the economic burden of injury is staggering, as are injury disability statistics. public health and injury health professionals focus most primary health promotion efforts on prevention of degenerative diseases because these are the leading causes of death amenable to risk factor modification, and in the case of sports medicine focus on the prevention of sports injuries. however, is enough being done to prevent the overall burden of injuries? paradigm shift: injuries are not ‘accidents’ injuries occur in predictable patterns, a consequence of host (human), agent (energy or vector), and environment (physical and socio-cultural) interaction. acute exposure to thermal, mechanical, electrical, or chemical energy, or lack of life-needed elements (heat or oxygen), causes injury. unintentional injury, although unplanned, stafford c rorke (dphil, facsm) wellness, health promotion and injury prevention program, school of health sciences, oakland university, rochester, michigan, usa correspondence to: stafford rorke (rorke@oakland.edu) the injury burden ̶ sport and exercise scientists can contribute more to public health fig. 1. how injuries claim lives. reproduced with permission from the who (2010). 3 (other includes smothering, asphyxiation, choking, animal and venomous bites, hypothermia and hyperthermia, and natural disasters.) sajsm vol 23 no. 4 2011 137 is typically preceded by an unsafe act or condition, yet people continue to speak of accidents. the word ‘accident’, although commonly used, is a vague, misleading term suggesting lack of understanding of the causes of injury, attributing injury to random chance, luck or fate. consequently, many continue to think of injuries as haphazard, uncontrolled factors, rarely considering injury likely, or within personal control. denial is often a factor. little attention is paid to injury, except following a catastrophic event or natural disaster when scores are killed or injured, or only when a high-profile personality dies tragically. negligible education of the public occurs, except in the context of questions raised about such events. correct terminology should be used by health professionals. there is general consensus among injury prevention advocates that the terms ‘unintentional injury’, ‘intentional injury’ (or ‘violence’ – self-inflicted, interpersonal, or collective), ‘injury prevention’, and ‘injury control’ are appropriate terms, rather than the use of the word ‘accident’. routine reference to a specific injury mechanism, such as motor vehicle crash, road traffic injury, fall, poisoning, or burn, rather than an ‘accident’ is better use of terminology. 4 what should health professionals know and do? ● develop knowledge of basic injury epidemiology theory and practice plus awareness of disparities in injury occurrence. 4 ● know major injury risks and leading injury causes (for south african data refer to norman et al.). 5 ● recognise that it costs less to prevent than treat an injury. 4 ● attend to personal safety. ● know what works in injury prevention. 4 ● design basic injury prevention interventions by applying the es of injury prevention: ● education: use the haddon ten principles of injury prevention; the haddon matrix and haddon matrix third dimension; and/or the sportsmart® 10-point plan for sports injury prevention. 4,6 ● environment/engineering: modify the physical and social environment. 4 ● enforcement: support existing and appropriate new safety legislation. 4,6 ● emergency response: know disaster response methods, first aid, and practise safety drills at home/work. 6 ● evaluate: begin injury surveillance and injury prevention programme evaluation. 4 ● create personal responsibility for injury in the minds of people. however, given that exclusive emphasis on personal responsibility can result in a climate of blame, attention should also be given to environmental as well as socio-cultural factors in injury causation. a complex area, models outlining ecological factors in injury causation (individual, interpersonal, community, and society) by krug et al. (2002) and hanson et al. (2005) are recommended reading. 6 for further information about public health injury prevention refer to the references. 4,6 conclusion unintentional and intentional injury are often overlooked but are leading causes of years of potential life lost and result in a severe burden to society. health professionals can play an important public health role through increased personal responsibility and by including elements of injury prevention intervention, control, and safety promotion in daily activities. an effective injury prevention advocate needs to be informed about injury epidemiology, and should be seen to proactively and assertively encourage implementation of effective injury prevention strategies. only then can we hope to see a decline in untimely death and disabling non-fatal injury. references 1. holtzhausen lj. exercise is medicine® in south africa workshop: the way forward. 14th biennial south african sports medicine congress, october 2011. 2. derman w. the responsibility of sport and exercise medicine in preventing and managing chronic disease: applying our knowledge and skill is overdue. 14th biennial south african sports medicine congress, october 2011. 3. injuries and violence: the facts. geneva: world health organization, 2010. available at: http://whqlibdoc.who.int/publications/2010/9789241599375_ eng.pdf (accessed 27 october 2011). 4. christoffel t, gallagher ss. injury prevention and public health, practical knowledge, skills, and strategies. 2nd ed. boston: jones and bartlett, 2006. 5. norman r, matzopoulos r, groenewald p, bradshaw d. the high burden of injuries in south africa. world health organization bulletin 2007;85(9):695702. available at: http://www.who.int/bulletin/volumes/85/9/06-037184-table-t1.html (accessed 27 october 2011). 6. rorke sc. prevention of injury during physical activity. international journal of body composition research 2010;7( suppl.):45-50. (suppl: selected papers from the xxvth international symposium of the international council of physical activity and fitness research.) introduction rugby union is a team sport involving contact and collision of players running at fast speeds, 1 and consequently has a high injury rate. 2 since the advent of professionalism in rugby union in october 1995 3-5 professional players have become full-time athletes, with a greater emphasis on training for strength, speed and stamina, 6 increase in size, 5,7 speed and power, 4,5 and improvement in rugby skills. 3 professional rugby players sustain considerably more injuries than amateur players, 3,6,8 probably as a result of the greater size of the players, the faster pace at which the game is played, and the greater impact forces associated with these changes. 3,9,10 the super 14 (previously the super 12) is a popular professional rugby tournament between regional sides from south africa, new zealand and australia. since the inception of this tournament, professional rugby union players have played significantly more rugby matches each year. many elite south african players, who also play in national provincial tournament and international matches, may participate in as many as 35 matches in one season. the multiplicity of factors that contribute to injury in rugby union makes it difficult to identify causality. 9 however, to adequately condition players, reduce their risk of injury, and treat and rehabilitate rugby injuries appropriately, it is important to gain a better understanding of the nature and causes of rugby injuries, in particular their association with training. 2 therefore, the purpose of this study was to describe the incidence of injuries in a professional south african super 12 rugby team over 3 years (2002 2004), and to identify any associations between injury rates and the mode and volume of training. methods participants during the off-season 40 contracted players were selected to form part of the super 12 rugby union training squad. twenty-two of the initial 40 players were forwards, and 18 were backline players. in february, the number of contracted players was reduced to 28 (15 forwards and 13 backline players). the injured players in this study (n=38) were all male (26±2 years of age). in accordance with similar research, 11 and due to the nature of the professional game, the individuals who comprised the squad varied over the 3 years. ten original research article training volume and injury incidence in a professional rugby union team abstract objective. to describe the incidence of injuries in a professional rugby team, and to identify any associations between injury rates and training volume. methods. this retrospective, descriptive study included all injuries diagnosed as grade 1 and above in a south african super 12 rugby team. injury incidence and injury rates were calculated and compared with training volume and hours of match play. results. thirty-eight male rugby players were injured during the study period. the total number of annual injuries decreased from 50 (2002) to 38 (2004) (χ 2 =0.84, p=0.36). the number of new injuries showed a similar trend (χ 2 =2.81, p=0.09), while the number of recurring injuries increased over the 3-year period. there was a tendency for total in-season injury rates to decrease over the 3 years (χ 2 =2.89, p=0.09). the pre-season injury rate increased significantly over the 3 years (χ 2 =12.7, p<0.01), coupled with a reduction in training exposure over the pre-season phase. conclusions. one has to be cognisant of the balance between performance improvement and injury risk when designing training programmes for elite rugby players. although the reduction in training volume was associated with a slight reduction in the number of acute injuries and in-season injury rates over the three seasons, the performance of the team changed from 3rd to 7th (2002 and 2004, respectively). further studies are required to determine the optimal training necessary to improve rugby performance while reducing injury rates. correspondence: dr wayne viljoen manager boksmart national rugby safety programme, sa rugby (pty) ltd po box 99 newlands 7725 tel: +2721-659 6732 e-mail: waynev@sarugby.co.za wayne viljoen (phd, cscs)1 colleen j saunders (bsc (med) hons (exercise science))2 greg d hechter (ba hons (biokinetics))3 kerith d aginsky (phd)2 helen b millson (mphil (sports physiotherapy))3 1 sa rugby (pty) ltd, cape town 2 uct/mrc research unit for exercise science and sport medicine, department of human biology, university of cape town 3 western province rugby (pty) ltd, cape town sajsm vol 21 no. 3 2009 97 of these players were also part of the south african national squad. informed consent was obtained by the union, and the ethics committee of the university of cape town approved this study. preparation for the super 12 tournament the off-season training cycle extended from mid-november to middecember every year. players then had an active rest period until the first week in january, when pre-season training began. the preseason training period entailed formalised strength and conditioning sessions, rugby training, training camps, unofficial ‘friendly’ matches (n=3, 2002; n=3, 2003; n=2, 2004), and specific individualised preparation. the super 12 tournament consisted of 5, 3 and 4 regional teams from new zealand, australia and south africa, respectively, began in mid-february, and continued until mid-may. the number of matches varied depending on how well the team fared in the tournament (n=12, 2002; n=11, 2003; n=11, 2004). players had approximately 2 weeks off at the end of the tournament and then participated in the national provincial tournament and/or in international test matches. off-season musculoskeletal evaluations and medical screening assessments by the physiotherapist and the team sports physician precluded any previously diagnosed injuries and injuries sustained during other tournaments from being carried over to the analysis of the current study. data collection data were collected under the guidance of the same team physiotherapist and strength and conditioning trainer for the duration of the study. all injuries requiring medical attention, 12,13 diagnosed as grade 1 or above, were documented either directly after or within 5 days of the injury occurring, regardless of whether or not the injury resulted in the player missing training or not playing in a match. 11 a grade 1 injury was defined as one in which there was pain, with minimal loss of muscle function or strength. 14 we are cognisant of the consensus document on injury definitions published in 2007. 12 however, as our study was conducted before the consensus paper was published, the definition of injuries in our study was slightly different. an examination of the consensus definition suggests that the definition used in this study may slightly over-estimate the occurrence of an injury compared with the consensus definition. injury rates injury rates were determined using previously described methods and expressed as the number of injuries sustained per 1 000 hours at risk. 2,11-13,15-17 match injury rates were calculated on the premise that there were only 15 player positions on the field, 18 regardless of any substitutions made during the game. match injury rates were computed under the assumption that rugby union matches last on average 80 minutes (1.33 hours) per game. 9,11,18,19 training injury rates were reported as a function of total training exposure time. 13 • match injury exposure (mie) was determined by the number of games played during the specified seasonal cycle: mie = hours of play (1.33) x no. of players on the field (15) x no. of matches played. • match injury rates were then calculated: match injury rates = (no. of injuries during matches/mie) x 1 000. • training injury exposure (tie) was determined in a similar way: tie = hours of supervised training x no. of contracted players (either 40 or 28). 98 sajsm vol 21 no. 3 2009 total injury 30 40 50 60 n u m b er o f in ju ri es in-season match injury rates 0 50 100 150 200 250 total injury rates 0 5 10 15 training injury rates 2002 2003 2004 0 1 2 3 4 overall match injury rates 0 50 100 150 200 in ju ri es p er 10 00 p la ye r h o u rs (a) (b) (c) (d) (e) figure 1fig. 1. the total number of injuries and injury rates incurred over a 3-year time period in a super 12 rugby union team. (a) total number of injuries incurred over the 3 years; (b) total injury rates over the 3 years, combining match and training injury rates; (c) in-season match injury rates; (d) overall match injury rates combining preand in-season rates; (e) training injury rates over the 3 years. • training injury rates were then calculated: training injury rates = (no. of injuries during training/tie) x 1 000. • subsequently total injury rate was determined as the number of injuries sustained in a seasonal cycle: total injury rates = (no. of injuries sustained/(mie+tie)) x 1 000. these were determined for both pre-season and in-season periods. statistical analysis basic descriptive statistics were used to explain the accumulated injury and training data over the 3 years. the 95% confidence intervals (cis) for the injury incidence data were calculated using an exact binomial distribution. differences in the incidence of injuries between categories for the three seasons were assessed using a chi-square analysis for trend (χ 2 ). additionally, year-by-year comparisons between data were done using a 2 x 2 contingency table chi-square analysis applying yates’ continuity correction. statistical significance was accepted when p<0.05. results injury incidence table i and fig. 1a show that the total number of injuries incurred per year decreased gradually, but not significantly, from 50 (2002) to 38 (2004) χ 2 =0.84, p=0.36). the number of new injuries showed a similar trend, decreasing from 38 (2002) to 20 (2004) (χ 2 =2.81, p=0.09). when these values were normalised to the number of injured players, a similar pattern was found: 2.60 (2002), 1.82 (2003), and 1.80 (2004) injuries per injured player. the number of recurring injuries increased over the 3-year period from 12 (2002) and 10 (2003) to 18 (2004). although this increase was not statistically significant (χ 2 =0.63, p=0.43), it is clinically relevant as it is known that recurrent injuries are frequently under-reported within a season by nature of their definition. 13 table ii and figs 1 and 2 specify the overall training exposure and injury rates within the super 12 team over the 3 years. table ii shows that the number of match injuries sustained during the super 12 season decreased from 38 (2002) to 27 (2003) and 30 (2004). while there was a tendency for a reduction in in-season match injury rates (χ 2 =3.44, p=0.06), the overall match injury rates remained relatively unchanged over the 3 years (χ 2 =0.31, p=0.58). in the pre-season phase, table ii shows an increase in the number of hours trained per match over the 3 years. however, this may be misleading because in 2004 the team played one less pre-season ‘friendly’ match. if they had played the same number of pre-season ‘friendly’ matches in 2004, the training hours per match would have been 23.7 instead of 35.6. table ii also shows a meaningful reduction in training per match during the competition season in 2003 (9.0 v. 7.1 v. 7.3 hours per match – 2002, 2003, 2004, respectively), coupled with a tendency for the total in-season injury rates to decrease over the 3 years (χ 2 =2.89, p=0.09). the pre-season injury rate, however, increased significantly over the 3 years (χ 2 =12.7, p<0.01), and was coupled with a reduction in tie over the pre-season phase – 3 540 (2002), 3 671 (2003) and 2 847 (2004) player exposure hours. the total injury rates, as with the abovementioned overall match injury rates over the entire training sajsm vol 21 no. 3 2009 99 table i. number of injuries sustained and overall time spent on training (hours) from 2002 to 2004 2002 2003 2004 number of injured players 19 22 21 recurrent injuries 12 10 18 new injuries 38 30 20 total injuries 50 40 38 off-season training (h) 32.7 28.1 30.7 pre-season training (h) 56.2 63.8 40.5 combined offand pre 88.8 91.8 71.2 -season training (h) in-season training (h) 107.7 78.6 79.9 overall training time (h) 196.5 170.4 151.1 table ii. training injury exposure and injury rates within a super 12 rugby team over a 3-year period match injuries hours of training total ir seasonal cycle mie (h) no. of injuries match ir (95% ci) tie (h) per match (95% ci) 50 0.8 2002 pre 60 3 (10.4 139.2) 126.7 3 540 29.5 (0.2 2.4) 38 145.8 (91.2 169.7) 14.4 7.3 in 240 35 (103.7 196.9) 3 015 9.0 (10.6 19.2) (5.4 9.6) 50 2.4 2003 pre 60 3 (10.4 139.2) 96.4 3 671 30.6 (1.1 4.6) 6.5 27 109.1 (64.5 137.2) 12.8 in 220 24 (71.2 158) 2 200 7.1 (8.7 18.1) (4.7 8.8) 175 4.2 2004 pre 40 7 (73.4 327.8) 115.4 2 847 35.6 (2.1 7.3) 7.1 30 1 04.5 (79.2 160.6) 10.6 (5.0 9.8) in 220 23 (67.4 152.7) 2 238 7.3 (6.9 15.5) mie = match injury exposure; tie = training injury exposure. all injury rates (ir) are represented as the number of injuries incurred per 1 000 hours of player exposure, and the 95% confidence intervals (cis) are represented in parentheses. for this table, the pre-season represents both the offand pre-season time periods. season (off-, preand in-season), remained similar over the 3 years (χ 2 =0.01, p=0.90). training analysis over the 3 years seventy-four per cent of all injuries sustained over the 3 years occurred in a rugby match while 21% were related to rugby practice. very few injuries were related to gym, rugby fitness conditioning or other causes. it is however prudent for the development of appropriate injury prevention strategies in rugby union to analyse the training patterns utilised in this study, as much more time is spent training for rugby than playing rugby. 15 table i shows the breakdown of time spent within the various training cycles over the 3 years. off-season training time remained similar. however, it is evident that pre-season training volume increased slightly in 2003 (56.2 63.8 hours), and then decreased by 37% in 2004 to 40.5 hours (fig. 2c). although not significant (χ 2 =2.14, p=0.14), this reduction has practical importance and is reflected in the combined preparatory training cycle (91.8 71.2 hours) (χ 2 =1.12, p=0.29). a noticeable 27% decrease in in-season training volume (χ 2 =1.97, p=0.16) was observed between 2002 and 2003 (fig. 2b) and this reduction was maintained in 2004. if one compares the overall time spent on training, it is clear (fig. 2a) that there was a noticeable trend towards a reduction in training volume over the 3 years (χ 2 =3.06, p=0.08). table iii shows the breakdown of the training data collected over the 3-year study period. rugby conditioning or fitness training contributed to 8% of the total training time over the 3 years and formed 23%, 12% and 2% of the off-, preand in-season phases, respectively. conditioning was defined as any form of rugby fitness training such as anaerobic intervals, aerobic training, fuel mix conditioning, and speed and agility training, 15,16 and played a larger role in the offand pre-season than during the in-season. gym training formed 23% of the total training time, and contributed to 35%, 19% and 21% of the off-, preand in-season phases, respectively. the time spent on gym training in the pre-season phase was reduced over the 3 years (2002: 26%; 2003: 16%; 2004: 14%). rugby training sessions were defined as including structured game phase plays, skills training, kicking sessions, split sessions, defensive sessions, line outs, scrummaging, rucks, mauls and match training, 15,16 and formed 53% of the total training time contributing to 36%, 49%, and 62% of the off-, preand in-season training phases, respectively. the amount of time spent on rugby training during the in-season was also reduced over the 3 years (2002: 67%; 2003: 61%; 2004: 59%). the eco-challenge, a 24-hour endurance event during a training camp, was included in this analysis as it contributed to a large amount of tie during 2003. training injury rates (fig. 1e) accounted for 1.9 injuries/1 000 player training hours over the 3 years studied (2002: 1.8 (95% ci: 0.9 3.2); 2003: 2.2 (95% ci: 1.2 3.8); 2004: 1.6 (95% ci: 0.7 3.1)). discussion injury incidence the first finding from this study was that the number of total injuries (fig. 1a) and number of new injuries (table i), albeit not significant, gradually decreased over the 3 years. however, when comparing the total (fig. 1b) and match injury rates (fig. 1d) this downward trend was not evident (table ii). match injury rates tended to decrease between 2002 and 2003, but increased again in 2004. as match injuries contributed to most injuries sustained during the season, the same pattern reflected in the overall injury rates (table ii). the lower injury rate in 2003 coincided with a sizeable reduction in in-season training volume. the medical and coaching staff then reduced the pre-season training volume in 2004, which corresponded to match and total injury rates over the season, returning to levels similar to those of 2002. it would appear that training reductions had a tendency to lower the in-season match (p=0.06) and in-season total (p=0.09) injury rates over the 3 years, albeit not significantly, with the most prominent reduction between 2002 and 2003. total preseason injury rates and the number of recurrent injuries show the opposite trend, for which there were two possible reasons. firstly, newly contracted players from other unions may have been brought into the squad with pre-existing or unrehabilitated injuries. secondly, the rest period between the previous tournament and the start of the new season did not always allow sufficient time to rest, recover and completely rehabilitate with regard to injuries. the only major change in training between 2003 and 2004 was the reduction in pre-season training volume (table i). it has previously been suggested that training volume may significantly affect injury rates over a competitive season. 11,20 the overall number of hours spent training during the pre-season is significantly higher than that during the in-season, 15 and pre-season training contributes to approximately 38% of all training injuries. 17 a previous study showed that the likelihood of injuries in rugby league increased with increasing pre-season training loads. 20 however, when the authors examined the early and late competition phases in the same team, increases in training load showed no further 100 sajsm vol 21 no. 3 2009 120 130 140 150 160 170 180 190 200 210 220 2002 2003 2004 0 10 20 30 40 50 60 70 70 80 90 100 110 120 t ra in in g ti m e (h o u rs ) (a) (b) (c) total in season pre season fig. 2. training volumes over the 3-year period studied. (a) total training volumes over the 3-year period expressed in hours, combining off-, preand in-season training; (b) total in-season training volumes; (c) total pre-season training volumes. increases in injury incidence. 20 another study using rugby league players showed a 10 16% reduction in pre-season training to be effective in reducing injury rates by 40 50%, without compromising fitness. 21 however, reductions in pre-season training may not necessarily reduce the risk of ensuing injury. 8 other research has shown that strenuous physical activity of 5 39 hours per week has a protective effect against injury but pre-season exposure of greater than 39 hours a week was associated with a greater risk of injury. 9 during the pre-season, there are both higher training loads and a greater emphasis on tackling and defensive drills, thereby increasing contact exposure. it is therefore inevitable that injuries will result from the pre-season training. 20 although there is evidence to support reducing the pre-season training load in rugby league, 21 the data from the current rugby union study question the effectiveness of reducing the pre-season training load too much. appropriate preseason conditioning is necessary to prepare collision sport athletes for the physiological and musculoskeletal demands of competition. 20 based on the current data, it appears as if the reduction in in-season training volume alone may be more effective in lowering injury rates over a competitive season. although not significant, the noticeable reduction in in-season match injury rates (2002 2003) and in-season total injury rates (2002 2004) provides moderate support for this conclusion. nonetheless, with the reduction in overall training load over the 3 years, there was no statistically significant improvement in either the number of injuries or the overall injury rates. in addition, it should be noted that the team studied here ended 3rd, 9th, and 7th in the super 12 tournament during 2002, 2003 and 2004, respectively. this raises questions around the effect it may have on the overall performance of the team. the team had most injuries when they ended 3rd and least injuries when they ended 9th in the tournament. it is currently a challenge for strength and conditioning specialists to establish the optimum balance between training volume and intensity to effectively reduce injuries without compromising the necessary improvements in physical fitness and performance. 20,21 training effects although the incidence of injury during training is far less than during matches, one cannot negate the possible effect of rugby training as a cause of injury. 15 unlike during the match situation, one can to a large extent control what happens during training. 17 because of the physical nature of rugby, training sessions require adequate intensity to optimally develop the fitness parameters required to compete effectively. 21 the effects of so-called ‘match fitness’ drills that encompass rugby-specific training, such as physical impact drills, have not been sufficiently researched. game-specific drills incorporating elements of contact such as rucks and mauls have the highest risk of injury. 15 further study is required to ascertain the level and progression of match fitness conditioning necessary to adequately prepare players for rugby matches and reduce the risk of injury. 9 conclusion this study showed that a reduction in in-season and overall training volume was associated with a slight reduction in the number of acute injuries and in-season injury rates over the three seasons. the prevention strategies, however, had minimal effect on overall match, training and total injury rates and the performance of the super 12 rugby team as defined by their position on the log, which tended to decline. one has to be cognisant of the fine balance between performance improvement and the risk of injury when designing training programmes for elite rugby players. 15 further studies are required to determine how much training is optimal to maintain or increase rugby performance while effectively reducing injury rates. 20,21 references 1. duthie g, pyne d, hooper s. applied physiology and game analysis of rugby union. sports med 2003;33(13):973-991. 2. brooks jh, fuller cw, kemp sp, reddin db. epidemiology of injuries in english professional rugby union: part 1 match injuries. br j sports med 2005;39(10):757-766. 3. bathgate a, best jp, craig g, jamieson m. a prospective study of injuries to elite australian rugby union players. br j sports med 2002;36(4):265269. 4. silver jr. the impact of the 21st century on ruby injuries. spinal cord 2002;40:552-559. 5. williams jp. rugby union. spinal cord 2002;40(12):669. 6. garraway wm, lee aj, hutton sj, russell eb, macleod da. impact of professionalism on injuries in rugby union. br j sports med 2000;34(5):348351. 7. olds t. the evolution of physique in male rugby union players in the twentieth century. j sports sci 2001;19(4):253. 8. lee aj, garraway wm, arneil dw. influence of preseason training, fitness, and existing injury on subsequent rugby injury. br j sports med 2001; 5(6):412-417. 9. quarrie kl, alsop jc, waller ae, bird yn, marshall sw, chalmers dj. the new zealand rugby injury and performance project. vi. a prospective cohort study of risk factors for injury in rugby union football. br j sports med 2001; 5(3):157-166. 10. silver jr. professionalism and injuries in rugby union. br j sports med 2001;35(2):138. 11. millson hb, hechter gd, aginsky kd, bolger c, saunders cj. the nature and incidence of injuries in a currie cup rugby team from 2001 to 2003. s afr j sports med 2005;17(2):13-17. 12. fuller cw, molloy mg, bagate c, et al. consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union. clin j sports med 2007;17:177-181. 13. brooks jh, fuller cw. the influence of methodological issues on the results and conclusions from epidemiological studies of sports injuries. illustrative examples. sports med 2006;36(6):459-472. 14. brukner p, khan k. clinical sports medicine. sydney: mcgraw-hill, 1994. 15. brooks jh, fuller cw, kemp sp, reddin db. epidemiology of injuries in english professional rugby union: part 2. training injuries. br j sports med 2005;39(10):767-775. 16. brooks jh, fuller cw, kemp sp, reddin db. a prospective study of injuries and training amongst the england 2003 rugby world cup squad. br j sports med 2005;39(5):288-293. 17. holtzhausen lj, schwellnus mp, jakoet i, pretorius al. the incidence and nature of injuries in south african rugby players in the rugby super 12 competition. s afr med j 2006;96(12):1260-1265. 18. best jp, mcintosh as, savage tn. rugby world cup 2003 injury surveillance project. br j sports med 2005;39(11):812-817. 19. garraway wm, macleod dad. epidemiology of rugby football injuries. lancet 1995;345(1485):1487. 20. gabbett tj, domrow n. relationships between training load, injury, and fitness in sub-elite collision sport athletes. j sports sci 2007;25(13):15071519. 21. gabbett tj. reductions in pre-season training loads reduce training injury rates in rugby league players. br j sports med 2004;38(6):743-749. sajsm vol 21 no. 3 2009 101 introduction physical activity is recognised as a central component of overall approaches to primary prevention in reducing morbidity and mortality and improving well-being. 1 however, current societal trends have led to decreases in energy expenditure. 2 encouraging the sedentary person to be more active is a public health priority and the health promotion agenda for the 21st century includes promoting incidental physical activity as part of an overall plan for active living. 3 therefore, the current emphasis in physical activity promotion is on the accumulation of lifestyle activity. 4-6 consistent with the current recommendations for physical activity, people should be encouraged to accumulate physical activity throughout the day. 7 even small amounts of activity may lead to the accumulation of an adequate level of energy expenditure over the course of the day. 8 an option easily accessible and feasible to most people for accumulating incidental physical activity is the use of stairs instead of an escalator or lift, particularly in an occupational setting where there are likely to be multiple trips during the day. stair climbing is a physiologically vigorous physical activity shown to require 8.6 times more energy expenditure than the resting state. 9 regular stair climbing also has well-documented health dividends such as increased fitness and strength, weight loss, improved lipid profiles and reduced risk of osteoporosis. 10 in addition, stair climbing is free and readily available to most people. most studies that have attempted to increase the use of stairs compared with an original research article are point-of-decision prompts in a sports science and medicine centre effective in changing the prevalence of stair usage? a preliminary study abstract objective. to determine the impact of a signed intervention on promoting stair versus lift usage in a health and fitness facility. design. a 3-week observational study in which a simple time series design of collecting data before, during and after the introduction of an intervention was used. setting. the sports science institute of south africa (ssisa): a 5-storey building with a centrally located lift lobby and internal stairwell. method. observers were placed unobtrusively on the ground floor, with good visibility of lift/stairwell, to observe ascending movement of students, staff, tenants, visitors and patients 4 hours/day (07h00 09h00, 16h00 18h00), 4 days/week for 3 weeks. during week 2, motivational signs were displayed on the wall next to the lift and stairs and on the floor leading to the stairwell. in week 3, signage was removed. factors considered in predicting stair use were gender, phase of intervention, and whether persons were staff/students or visitors. results. a total of 4 256 person-counts were recorded. prevalence of stair use increased from 43% before the intervention correspondence: julian d pillay department of basic medical sciences faculty of health sciences durban university of technology po box 1334 durban 4000 south africa tel.: +27 31 3732398 fax: +27 866 741067 e-mail: pillayjd@dut.ac.za julian d pillay (mph)1,2 tracy kolbe-alexander (phd)1 masturah achmat (bsc hons (biokinetics))1 madelaine carstens (bsc hons (dietetics))1 estelle v lambert (phd)1 1 uct/mrc research unit for exercise science and sports medicine, faculty of health sciences, university of cape town 2 department of basic medical sciences, faculty of health sciences, durban university of technology to 53% during the intervention to 50% after the intervention. odds of using the stairs during the intervention increased by 45% (odds ratio (or) 1.45, 95% confidence interval (ci) 1.25 1.68) (p<0.00001), were 41% higher for staff/students compared with visitors (p<0.00001) and were 55% greater for women (p<0.00001). these effects did not change significantly after the intervention and stair use remained modestly higher than before the intervention. conclusion. signed intervention produced significant increases in stair usage during and after the intervention. these findings support the effectiveness of point-of-decision prompts for changing behaviour, and highlight potential factors influencing the impact of such messages. 58 sajsm vol 21 no. 2 2009 www.saasta.ac.za/sciencelens southern african science lens a p h o t o g r a p h i c c o m p e t i t i o n t o c e l e b r a t e a f r i c a n s c i e n c e capture stunning, dramatic, spectacular images related to science and technology for deadline: 14 september 2009 organised and sponsored by the south african agency for science and technology advancement (saasta) supported by canon sa categories • science in action • science as art • science close-up • science of sport • i see s&t (for learners) the challenge capture the beauty and excitement of science and technology on film. show how it benefits our daily lives. the competition is open to professional photographers and amateurs. what’s in it for you? • prize for overall winner of sa science lens 2009: canon eos 1000d with lens kit • prizes for the first four categories: a first prize of r10 000 and two r2 500 prizes for runners-up • state-of-the-art canon cameras for winners and their schools in the i see s&t category • special incentives for science centres to enter learners’ photographs 2009 scilens ad:layout 1 2009/05/13 9:13 am page 1 escalator/lift have been successful. 11-22 few studies report lack of improvement during and/or after an intervention. 23,24 a more recent form of health promotion is emphasis on the use of point-of-choice prompts to encourage stair climbing in the workplace. 5,25 the aim of this study was to assess the effectiveness of a signed intervention to promote the use of stairs in a health and fitness facility which ultimately encouraged students, staff and visitors to increase their level of incidental physical activity. method formative work before the start of this study, focus group discussions were conducted at the sports science institute of south africa (ssisa). these discussions were conducted among students and staff to determine the perceptions around health, fitness and behavioural patterns in terms of incidental physical activity such as stair usage. e-mails were sent to students and staff, inviting them to attend a focus group discussion, with available time slots indicated. two focus group discussions were conducted with 5 participants and 2 facilitators at each session, one facilitating discussion and the other scribing. the entire discussion lasted approximately 30 minutes and was recorded by means of an audiotape. facilitating factors and barriers to stair usage and willingness to change behaviour towards accumulating incidental physical activity such as stair usage were also discussed. the outcome of this phase of the study provided input towards the development of the intervention programme. intervention programme and observation procedure in the 3-week observational study, a simple time-series design of collecting data before, during and after the introduction of an intervention was used. the first phase of the study was the pre-intervention phase, the second was the intervention phase and the third was the post-intervention phase. each of the phases was conducted on the same days of the week (tuesday friday) and at the same time (07h00 09h00 and 16h00 18h00). data were recorded by a researcher who counted ‘people movements’ up the stairs or into the elevators. the researcher was positioned in the kiosk area on the ground floor of the building in an unobtrusive manner, but such that good visibility of lift/stair users was maintained at all times. the directional measure was important since the energy cost of ascending stairs is approximately 3 times that of descending stairs. 9 before the study it was decided that only ascending movement will be recorded. the intervention materials were displayed during week 2 of the study. the intervention consisted of coloured signs (21 cm x 30 cm) mounted on the wall next to the elevator and stair areas (fig. 1), and coloured, vinyl footprints stuck on the floor, which led people to the stairs. such signage aimed to provide a ‘point of choice’ motivational prompt to encourage staff and visitors to use the stairs as an alternative to the elevator to improve their health and fitness. 24 observational data collected by the researcher during the days and times specified were transformed into a percentage of number recorded and were subdivided into exercise science students/staff member (essm) and non-exercise science students/staff member (non-essm). the data were further stratified into gender-specific categories. table i. summarised counts of study pre pre post post intervention intervention intervention intervention intervention intervention (lift) (stairs) (lift) (stairs) (lift) (stairs) essm (males) 75 (56%) 58 (44%) 56 (30%) 129 (70%) 62 (43%) 81 (57%) essm (females) 58 (45%) 70 (55%) 65 (34%) 127 (66%) 53 (40%) 81 (60%) non-essm (males) 287 (60%) 190 (40%) 346 (51%) 327 (49%) 267 (53%) 242 (48%) non-essm (females) 277 (56%) 214 (44%) 373 (52%) 345 (48%) 252 (53%) 221 (47%) total 697 (57%) 532 (43%) 840 (48%) 928 (52%) 634 (50%) 625 (50%) (n=4 256) 1 229 (100%) 1 768 (100%) 1 259 (100%) fig. 1. message displayed in signage. % u s a g e fig. 2. comparative display of lift/stair usage at sissa before, during and after the intervention. 60 sajsm vol 21 no. 2 2009 fair consultants & promocorp (pty) ltd the data were analysed using statistica version 7 (statsoft inc., tulsa, ok, usa). logistic regression analyses were used, with lift/stair use as the dichotomous dependent variable. predictor variables such as gender and whether or not the individual was affiliated to the academic sports medicine unit (essm or non-essm) were entered into the model as independent variables. logistic regression of odds for using the stairs was determined with bonferroni correction for 3 comparisons (significance accepted at p<0.015). the focus group discussions were not statistically analysed, as the nature of the work was descriptive and was used to develop the signed intervention used in the study. results formative work themes that emerged from the discussions in the focus groups were categorised as facilitating factors and barriers to the use of stairs in the accumulation of intended and/or incidental physical activity. the long waiting period for an available lift was the primary facilitating factor to stair use. the congestion at the lift lobby during peak times was also a facilitating factor to stair use in some participants. these participants became accustomed to stair use and therefore continued this practice throughout the day. a further facilitating factor to stair use was the location of the staircase. participants interviewed reported that the positioning of the staircase provides a good view of the activities (usually training sessions) taking place on the quadrangular area on the first floor of the building. the main barrier to the use of the stairs indicated by students/staff was laziness and/or being too busy. in addition, some participants felt that using the stairs would make little/no difference towards improved health and fitness, while others felt that they accumulated enough intended physical activity and did not see the need for additional benefits that may be gained through stair usage. intervention programme and observation procedure a total of 4 256 counts were recorded and entered onto a microsoft xl spreadsheet. the summarised counts are indicated in table i and represented graphically in fig. 2. the recorded data were entered into the logistic regression model and logistic regression of odds for using the stairs before intervention to intervention (with bonferroni correction) was calculated. the results indicated that there was a 45% increased odds of using the stairs from before intervention to intervention; a 41% increased odds if you were an essm; and a 55% greater odds if you were a woman. similarly, for comparison of intervention with post-intervention effects, those previously described for essm and gender remained – the behaviour did not regress significantly after intervention. in addition, comparison of pre-intervention with post-intervention data again showed the same effects for gender and essm, and the pre-intervention to post-intervention effects were statistically significant (p<0.015). discussion from previous studies it is apparent that there is a decline in physical activity levels as energy expenditure-associated work and daily living activities decrease. 26,27 interventions aimed at increasing incidental physical activity such as using the stairs over the lift have been shown to improve health and fitness levels. 9 consistent with previous studies, 16,27 the main barrier to the use of the stairs indicated by students/staff was laziness and/or being too busy. in addition, some felt that stair usage would not make a difference towards improved health and fitness. such information provides useful cues in developing appropriate health promotion initiatives that encourage and support behavioural change in this regard. andersen et al. 11 suggested that an increase in stair use may not prompt people to significantly alter their overall level of physical activity and that further investment in stair campaigns needs to be looked at with caution. this has been further supported by a study by marshall et al., 24 with a sample size more extensive than most other studies (approximately 158 000 counts compared with an average of a few thousand observational counts) and a longer intervention period (12 weeks compared with an average of 4 6 weeks). the study showed an initial increase in stair walking that declined to baseline levels at follow-up. similarly, auweele et al. 23 reported a significant increase in stair use for female employees and when a health sign was used. however, as with marshall et al., 24 this increased stair usage declined to baseline over the study period (7 weeks). two studies reported significant increases in stair use which were sustained between baseline and follow-up: follow-up at 2 3 weeks after a 4-month intervention period, 28 and follow-up at 2 weeks after a 6-week intervention period. 29 in the latter study, a significant effect on stair climbing (ascent) was seen (or 1.12, p<0.005). kerr et al. 30 reported no significant intervention effect for stair climbing, but there was a significant increase in stair descent (or 1.21, 95% ci 1.07 1.37). results of the present study add to the pool of supporting evidence that stair-promoting interventions are a viable public health strategy for increasing incidental physical activity. moreover, the key outcome intended to be achieved goes beyond simply choosing the stairs over the lift, but rather of bringing about behavioural change towards improved health and fitness. while public health promoters support the notion that accumulating incidental physical activity is a stepping stone towards behavioural change, further research is needed to determine the extent to which modest improvements in incidental activity produce more significant improvements in overall physical activity. a more objective and comprehensive view of overall stair use (e.g. a 24-hour, 7-days-a-week motion-sensing device 24 ) is also recommended so that the data are not subject to observer bias or periodic observation periods. in addition, more extensive long-term studies are needed to examine the loss of effect after an intervention. references 1. mathers c, vos t, stevenson c. the burden of disease and injury in australia. aihw cat. no. phe17. canberra: australian institute of health and welfare, 1999. 2. prentice am, jebb sa. obesity on britain: gluttony or sloth? bmj 1995;311:437-439. 3. world health organization. active living. geneva: who, 1997. www.who. int/hpr/active/objectives.html (last accessed 8 october 2007). 4. british heart foundation. coronary heart disease statistic: british heart foundation database, 1998. 5. department of health. at least five times a week: evidence on the impact of physical activity and its relationship to health. london: department of health, 2004. 6. us department of health and human services. physical activity and health: a report of the surgeon general. atlanta: centers for disease control, 1996. 7. jakicic jm, wing rr, butler ba, roberston rj. prescribing exercise in multiple short bouts verses one continuous bout: effects on adherence, cardio-respiratory fitness and weight loss in overweight women. int j obes 1995;19:893-901. 8. dunn al, andersen re, jakicic jm. lifestyle physical activity interventions: history, shortand longterm effects and recommendations. am j prev med 1998;15:398-412. 62 sajsm vol 21 no. 2 2009 untitled-1 1 6/4/09 10:52:44 am 9. basset dr, vachon ja, kirkland ao, howley et, duncan ge, johnston kr. energy cost of stair climbing and descending on the college alumnus questionnaire. med sci sports exerc 1997; 29:1250-1254. 10. boreham cga, wallace wfm, nevill a. training effects of accumulated daily stair-climbing exercise in previously sedentary young women. prev med 2000;30:277-281. 11. andersen re, franckowiak sc, snyder j, bartlett sj, fontaine kr. can inexpensive signs encourage the use of the stairs? results from a community intervention. ann intern med 1998;129:363-369. 12. andersen re, franckowiak sc, zuzak kb, cummings es, crespo cj. community intervention to encourage stair use among african-american commuters. med sci sports exerc 2000;32:s38. 13. blamey a, mutrie n, atichison t. health promotion by encouraged use of stairs. bmj 1995;311:289-290. 14. brownell kd, stunkard aj, albaum jm. evaluation and modification of exercise patterns in the natural environment. am j psychiatry 1980;137:1540-1545. 15. coleman kj, gonzalez ec. promoting stair use in a us-mexico border community. am j public health 2001;91:2007-2009. 16. kerr j, eves f, carroll d. posters can prompt less active individuals to use the stairs. j epidemiol community health 2000;54:942-943. 17. kerr j, eves f, carroll d. the influence of poster prompts on stair use: the effects of setting, poster size and content. br j health psychol 2001a;6:397-405. 18. kerr j, eves f, carroll d. encouraging stair use: banners are better than posters. am j public health 2001b;91:1192-1193. 19. kerr j, eves f, carroll d. getting more people on the stairs: the impact of a new message format. j health psychol 2001c;6:495-500. 20. kerr j, eves f, carroll d. six-month observational study of prompted stair climbing. prev med 2001d;33:422-427. 21. russell wd, hutchinson j. comparison of health promotion and deterrent prompts in increasing use of stairs over escalators. percept mot skills 2000;91:55-61. 22. webb oj, eves ff. promoting stair climbing: single vs. multiple messages. am j public health 2005;95:1543-1544. 23. auweele yv, boen f, schapendonk w, dornez k. promoting stair use among female employees: the effects of a health sign followed by an email. j sport exerc psychol 2005;27:188-196. 24. marshall al, bauman ae, patch c, wilson j, chen j. can motivational signs prompt increases in incidental physical activity in an australian health-care facility? health educ res 2002;17: 743-749. 25. stairwell to better health, 2004. http://www.cdc.gov/nccdphp/dnpa/ stairwell/index.htm (accessed 13 november 2007). 26. armstrong t, bauman a, davies j. physical activity patterns of australian adults. results of the 1999 national physical activity survey. aihw cat. no. cvd 10. canberra: australian institute of health and welfare, 2000. 27. pratt m, macera ca, blanton c. levels of physical activity and inactivity in children and adults in the united states: current evidence and research issues. med sci sports exerc 1999;31:526-533. 28. titze s, martin bw, seiler r, marti b. a worksite intervention module encouraging the use of stairs: results and evaluation issues. soc prev med 2001;46:13-19. 29. eves ff, webb oj, mutrie n. a workplace intervention to promote stair climbing: greater effects in the overweight. obesity 2006;14:2210-2216. 30. kerr j, eves f, carroll d. can posters prompt stair use in a worksite environment? j occupational health 2001;43:205-207. 64 sajsm vol 21 no. 2 2009 introduction hydrotherapy is an excellent training medium for rehabilitation in the athlete who is under time constraints for recovery after a sporting injury. 20 aquatic exercises have been recommended, especially in the initial phase of rehabilitation to allow early active mobilisation and to improve neuromuscular function. 14 the primary goals of accelerated rehabilitation following an acl reconstruction are to recover joint range of motion (rom), strength, ambulatory skills and return to previous activity or sport. 18,21 hydrotherapy may provide the ideal medium to accomplish these goals due to the positive effects of the physical properties of water on the human body, such as decreased pain, increased rom and flexibility, early restoration of joint mobility, reduced oedema and increased blood flow to muscles. 2,6,14,16,20 published research into the physical properties and biomechanical effects of water on the knee provides support for the use of hydrotherapy in knee rehabilitation. 2,14,15,16,20 biomechanical studies demonstrated that accelerated open (okc) and closed kinematic chain (ckc) exercises in water are not detrimental to the healing acl graft. 2,14,15 in water, the knee joint plays no role in the absorption of forces because the impact force is greatly reduced due to buoyancy. 11,12 this provides an opportunity to accomplish early full weight-bearing in water to enable gait re-education. hydrotherapy may thus increase a patient’s tolerance to rehabilitation programmes. although accelerated land-based programmes have been published extensively, a combination of accelerated land and hydrotherapy programmes has not been studied. a combined programme may be beneficial to sports participants as it allows more joint loading, aggressive rehabilitation and earlier return to function. 21 original research article accelerated hydrotherapy and land-based rehabilitation in soccer players after anterior cruciate ligament reconstruction: a series of three single subject case studies abstract objective. to investigate the effectiveness of accelerated rehabilitation and accelerated hydrotherapy after anterior cruciate ligament (acl) reconstruction in male athletes participating in soccer. design. a non-concurrent single subject, multiple baseline design (aba design) was conducted over 10 weeks. a series of three n=1 studies was conducted to assess the effect of an accelerated hydrotherapy programme on pain, function, and range of motion. setting. the study was conducted at a private physiotherapy practice in port elizabeth, south africa. interventions. the land rehabilitation programme was a homebased programme supervised every week by the physiotherapist. the accelerated hydrotherapy consisted of a 6-week programme, and participants attended two treatment sessions of accelerated hydrotherapy per week each of 30 minutes' duration. main outcome measures. the knee injury and osteoarthritis outcome scale (koos) as a subjective measure of pain, function and quality of life; the goniometer to measure active knee rom and the 6-minute walking test (6mwt) as an objective measure of function. results. all three patients demonstrated good improvement during the treatment phase for the koos scale and progressed well correspondence: professor quinette louw division of physiotherapy department of interdisciplinary health sciences faculty of health sciences stellenbosch university po box 19063 tygerberg 7505 republic of south africa tel: +27(021) 938 9301 fax: +27(021) 931-1252 e-mail: qalouw@sun.ac.za bridey-lee momberg (bsc, msc physiotherapy (omt)) quinette louw (bsc, masp, phd) lynette crous (bsc, msc) division of physiotherapy, university of stellenbosch in terms of their walking ability during the study. significant improvement was gained during the baseline phase for all three participants with high initial levels of knee flexion while active knee extension improved gradually in all three participants. conclusion. the study findings indicate that an accelerated landbased and hydrotherapy programme may be useful in improving patient outcomes and that there are no risks for harm. clinical relevance. the study findings indicate that accelerated hydrotherapy may be a useful and safe adjunct to an accelerated land-based programme after acl reconstruction. sajsm vol 20 no. 4 2008 109 the aim of this study was to investigate the effectiveness of the addition of accelerated hydrotherapy to standard accelerated land-based rehabilitation in reducing pain and increasing rom and functional outcomes after acl reconstruction in male athletes participating in soccer. methodology a series of three n=1 studies was conducted to assess the effect of an accelerated hydrotherapy programme on pain, function and rom. the sample comprised participants who fulfilled the following inclusion criteria: they were english-proficient male competitive soccer players (aged 20 44 years) who had suffered a traumatic acl injury while participating in soccer, who subsequently underwent unilateral left or right acl repairs (irrespective of dominance) and who suffered a complete acl rupture with or without an associated meniscal injury. participants were included in the study if they participated in soccer at a level where they played matches for a recognised team and participated in a league or tournament. the surgery was performed by the same surgeon who used the arthroscopic four-strand hamstring (semitendinosis and gracilis) single bundle graft method to repair the acl. participants were excluded from the study if they: fell outside the described age group, suffered an acl injury through another mechanism of injury other than soccer, were diagnosed with multidirectional instability of the affected knee, suffered any acute injury to the contralateral lower limb or had associated ankle and hip injuries on the ipsilateral side. ethics approval was obtained from the committee for human research at the stellenbosch university (project number: n06/10/207) and all subjects provided signed consent. study design a non-concurrent single subject, multiple baseline design (aba design) was conducted over 10 weeks. phase a1 represented the baseline phase, commenced at day 10 post-surgery, and consisted of an accelerated land rehabilitation programme. phase b represented the treatment phase and consisted of both land rehabilitation and accelerated hydrotherapy. the duration of phase b was 6 weeks. the three participants entered the treatment phase at different times in their post-surgical rehabilitation and this was allocated in a consecutive manner as presented in table i. phase a2 was the withdrawal phase, where the accelerated hydrotherapy was withdrawn and the accelerated land rehabilitation programme continued until 12 weeks after surgery (table i). the study was conducted at a private physiotherapy practice in port elizabeth, south africa. participants were recruited from the practice of an orthopaedic surgeon who had agreed to refer eligible patients. participants were referred once the surgeon was satisfied that structural stability was satisfactory after the surgery. a consecutive sampling method was used. since there was no order in which patients presented to the surgeon’s office, arguable random participants were recruited. outcome measurement three baseline measures for each outcome were measured before the participant entered the treatment phase. during the treatment phase six measurements for each outcome were recorded (these were taken before the treatment was administered) and during the withdrawal phase another three measures for each outcome were taken (table ii). reliability and validity of the outcome measures the intraand inter-tester reliability in the study by brosseau et al. was high for the universal goniometer with high intraclass correlation coefficients (iccs) for both flexion (r=0.99) and extension (r=0.9 0.98) for the knee. 3 the validity was studied using radiographs as the gold standard. 3 validity was high for measuring knee flexion (r=0.970.98), but lower for measuring knee extension (r=0.39-0.44). 3 koos is a knee-specific instrument which has 42 items in 5 separately scored sub-scales: pain, other symptoms, function in daily living (adl), function in sport and recreation (sport/rec), and knee-related quality of life (qol). 17 koos has been validated in participants undergoing acl reconstruction. 17 the 6-minute walking test (6mwt) is a time-modified test that originated from the original 12-minute walking test as a field test for assessing maximal oxygen uptake in athletes. kennedy et al. assessed the reliability and sensitivity to change of the 6mwt in hip and knee osteoarthritis (oa) sufferers with good results. 8 in the study by kennedy et al. the icc for the 6mwt was r=0.94 (0.88, 0.98). 8 study procedures each participant received a patient booklet (containing the consent form, information about the respective practices, summary of the rehabilitation programmes and exercise descriptions with appropriate diagrams) and a diary of compliance in which they were asked to record their compliance with the accelerated land rehabilitation programme. all participants received preoperative rehabilitation. this was a 6-week land-based programme and was administered by the researching physiotherapist. post-surgical management in hospital was standardised and consisted of circulatory exercises and mobilisation (partial weightbearing on two crutches) conducted by the researcher. for the first 10 days a standard rehabilitation protocol was followed (table iii). the study started on day 10 post-surgery. a table i. study phases pt d10-14 w 2-3 w 3-4 w 4-5 w 5-6 w 6-7 w 7-8 w 8-9 w 9-10 w 10-11 w11-12 1 acr h & acr h & acr h & acr h & acr h & acr h & acr acr acr acr acr 2 acr acr h & acr h & acr h & acr h & acr h & acr h & acr acr acr acr 3 acr acr acr h & acr h & acr h & acr h & acr h & acr h & acr acr acr d = days post-surgery; w = weeks post-surgery; acr = accelerated land rehabilitation programme; h & acr = accelerated hydrotherapy and accelerated land rehabilitation programme. a1 = baseline (acr only) b = treatment phase (acr and accelerated hydrotherapy) a2= withdrawal phase (acr only, accelerated hydrotherapy was withdrawn) 110 sajsm vol 20 no. 4 2007 subjective and physical examination was conducted according to the principles of maitland at commencement of the baseline phase. 7 a pilot study was done to determine the intertester and intratester reliability and to standardise the goniometry procedures. this was executed in the baseline phase and the measures were taken by the principal investigator and a second physiotherapist. each physiotherapist took two measures of the goniometer measurements on a given day. this was repeated on three separate occasions during the baseline phase for each of the participants. description of the intervention throughout the 10-week study the participants followed the accelerated land rehabilitation programme, beginning day 10 post-surgery until completion of the study at 12 weeks post-surgery. the land rehabilitation programme was a home-based programme supervised every week by the physiotherapist (table iv). the patient booklet provided a detailed description of each exercise and the compliance diary was kept. the land programme focussed on restoration of muscle strength, proprioception, functional strengthening and return to sport. 4 each of the three participants then entered the treatment phase at 2, 3 or 4 weeks post-surgery respectively. this consisted of a 6-week accelerated hydrotherapy programme (table v). the intervention of hydrotherapy was implemented at different times with the goal of observing a noticeable change with its implementation. thus this change could then be attributed to the addition of hydrotherapy if it occurred in each participant and not only due to post-surgical maturation. during the hydrotherapy phase, the participants attended two treatment sessions of accelerated hydrotherapy per week, each of 30 minutes’ duration, for the 6-week intervention period. they then ceased the additional hydrotherapy programme (at 8, 9 or 10 weeks in the study period respectively) and continued the land-based rehabilitation only for the withdrawal (a2) period. at 12 weeks the participants had their final assessment and the formal part of the study was completed. they then continued with the accelerated land rehabilitation programme, and were monitored and progressed on a monthly basis until 6 months after surgery, when they were referred for further sports-specific rehabilitation if necessary, until such time as they had returned to their sport. all outcomes were measured by the researcher. during the accelerated hydrotherapy phase, all outcomes were measured before the hydrotherapy session. further details of the interventions are available from the authors. data analysis all data were entered into microsoft excel for analysis. descriptive statistics were used to summarise the data. visual analysis of graphs and effect size were calculated to analyse performance. 1 an effect size of 2.6 was classified as small, 3.9 as moderate and 5.8 and higher a large effect. 19 intra-class correlations (icc) using the two-way model were calculated using the statistical programming language r. the iccs were calculated to determine the reliability of the knee rom measurements. results there was excellent intraand inter-tester reliability for knee flexion and knee extension in the pilot study. the icc values for knee flexion were 0.99 and 0.91-0.95 for knee extension intraand inter-tester reliability. participant descriptions participant 1 was a 26-year-old male who sustained an injury to his left knee 3 months before his scheduled acl reconstruction. the mechanism of injury was a twisting action of the knee on a fixed foot. he experienced immediate and continued pain and swelling after his injury. table ii. outcome measurement phase a1 (baseline) b (treatment) a2 (withdrawal) koos 3 measures 6 measures 3 measures goniometer 3 measures 6 measures 3 measures 6 mwt 3 measures 6 measures 3 measures participant 1 d10-14 w2-8 w8-12 participant 2 d10-w3 w3-9 w9-12 participant 3 d10-w4 w4-10 w10-12 koos = subjective pain, function and qol; goniometer = active rom; 6-minute walking test (6mwt) = function. table iii. initial post-surgical treatment (day 1 10) (macdonald et al., 10 tovin et al. 21 ) goal treatment improve circulation circulatory exercises restore range of motion (no restrictions except outside pain) assisted extension and flexion outside pain (25x), wall slides (25x), passive knee extension roll under ankle or prone hangs(10 minutes), hamstring and calf stretching (30 seconds, 3 x/day) improve strength isometric quadriceps (3x10) slr with hip flexion and hip abduction (3x10 each) restore and improve gait fwb on 2 crutches reduce swelling cryotherapy, rice regimen slr = straight leg raise; fwb = full weight bearing; rice = rest, ice, compression and elevation. sajsm vol 20 no.4 2008 111 participant 2 was a 28-year-old male who sustained an injury to his left knee 5 years ago. he underwent an arthroscopic debridement and returned to his activities of daily living. he then suffered a re-injury to his left knee 6 months before his scheduled acl reconstruction. the mechanism of injury was a fast extension of the knee during a fall. he experienced immediate and continued pain and swelling with a significant disturbance in gait pattern. participant 3 was a 43-year-old male who sustained an injury to his right knee 8 months prior to his scheduled acl reconstruction. the mechanism of injury was a twisting action of the knee on a fixed foot. participant 3 experienced immediate pain and swelling, but after a period of rest had attempted to return to soccer. however, he experienced pain, swelling and giving way of his right knee. koos scale in all three participants, 18 28% of improvement in the koos scores was demonstrated in the baseline phase. all three patients demonstrated good improvement during the treatment and withdrawal phases. the effect size for the three participants was 8.00, 8.66 and 6.00 and indicated that a large effect was obtained during the intervention and withdrawal phases. measurement four is the transitional measure between the baseline and treatment phase and was taken just before the accelerated hydrotherapy was commenced. the difference between measures three and four was -1 (57.5 56.5) and between measures four and five was 9 (56.5 65.4), illustrating that participant 3’s baseline had begun to stabilise and an increase in performance was noted after commencement of the accelerated hydrotherapy (fig. 1). objective functional ability 6mwt all three participants progressed well in terms of their walking ability. participants 1 and 2 demonstrated between 16% and 23% of their overall improvement in walking ability in the baseline phase. participant 3, however, demonstrated 57% of his total improvement during the baseline phase. the overall effect size (including treatment and withdrawal phases) for participant 1 was 4.38, 6.49 for participant 2 and 2.41 for participant 3. participant 1 and 2 thus demonstrated relatively better performance during the treatment and withdrawal phases compared with participant 3 (fig. 2). active knee flexion rom fig. 3 illustrates that all three participants started at a relatively high initial level of knee flexion and much improvement was gained during the baseline phase. thus the overall effect sizes (including treatment and withdrawal phases) were relatively smaller, 2.48 for participant 1, 3.50 for participant 2 and 1.79 for participant 3, as they had almost reached full range at the commencement of the hydrotherapy. the remainder of the study all three participants continued to improve their active flexion rom but at a slower rate, and measures began to plateau out towards the end of the study (fig. 3). table iv. accelerated land-based rehabilitation programme (fujimoto et al., 5 macdonald et al. 10 , muneta et al. 13 ) week criteria met treatment 0 2 weeks as post-surgical treatment (d 1-10) 2 weeks flexion to 90 continue with exercises, cycling 4 weeks continue with exercises, cycling strengthening exercises ckc (leg presses and squats) hip strengthening against resistance (f, e, abduction and adduction) ankle strengthening in standing (calf raises) full rom, no quadriceps lag, no ambulation without crutches limping and able to do slr 8 weeks cycling hamstring strengthening (concentric and eccentric) continuation of hip and calf strengthening gait re-education 10 weeks jogging (straight-ahead, level ground, with no pivoting) continuing with other exercises 12 weeks jogging continued 16 24 weeks full rom and quadriceps muscle return to non-pivoting sports (4 6 months) strength 85% of unoperated leg with isokinetic testing 24 32 weeks return to pivoting sports (6 8 months) table v. accelerated hydrotherapy programme (biscarini and cerulli, 2 kuehne and zirkel, 9 miyoshi et al., 11,12 poyhonen et al., 14 tovin et al. 21 ) goal treatment gait retraining gait training quadriceps and hamstring strengthening closed kinetic chain exercises open kinematic chain exercises strengthening and endurance training running cycling deep-water running techniques hip and calf maintenance and strengthening hip exercises and calf raises, kicking and vertical kicking balance and proprioception (perturbation protocol) balance and proprioception exercises plyometric training jumping, running, shuttle runs, side steps with increased speed sports-specific rehabilitation agility exercises making use of a ball 112 sajsm vol 20 no. 4 2008 sajsm vol 19 no. 4 2007 113 active knee extension rom active knee extension improved gradually in all three participants. at baseline, participant 1 had shown no change in his extension measure, participant 3 had shown a 45% improvement and participant 2 had 66% of his improvement occurring in the baseline phase. participant 1 demonstrated the largest effect (effect size 8.08) during the treatment and withdrawal phases compared with participant 2 (effect size 2.9) and participant 3 (2.66), although participant 2 obtained the most knee extension at the end of the study (fig. 4). discussion the study findings indicate that an accelerated hydrotherapy programme in addition to a land-based programme may be useful in improving patient outcomes and that there are no risks for harm. care and awareness of the healing hamstring at the donor site must, however, be kept in mind throughout the rehabilitation programme. the physical properties of water result in biological effects on the body such as the reduction in pain, increases in rom, improved coordination of movement and early restoration of joint rom. 2,6,14,16,20 these biological effects provide reasons why all the participants’ perceptions of their pain, symptoms, function and qol improved during the treatment phase with the addition of hydrotherapy. experimental studies demonstrate that hydrotherapy has a positive effect on the reduction of pain and improvements in functional scales after acl reconstruction. 9, 21 participant 3 showed a stabilising baseline at measures three and four and then a marked increase between measures four and five for the koos score (fig. 1). hydrotherapy may therefore have improved participant 3’s perception of his pain, symptoms, function and qol. participant 3 entered the treatment phase after a longer period compared with participants 1 and 2 and therefore his baseline measures may have stabilised and changes in performance after commencement of the hydrotherapy were more noticeable. the same change may not have been visible in the other two participants because of the unstable baseline phases shown in a number of koos measures for these participants; however, these two participants also demonstrated good effect of treatment on their koos scores. all participants demonstrated steady improvements in their walking ability throughout the study. participant 3 demonstrated relatively less effect during the treatment phase on walking ability. this may be because he started the hydrotherapy relatively later and had already regained significant improvement in walking ability before commencement of hydrotherapy. maturation was therefore a threat to the internal validity, and the effect of this may be most notable in participant 3. all participants obtained high initial knee flexion rom even before the start of the study, therefore relatively small treatment effects were noted during the treatment phase. the participants’ good knee flexion rom may be due to accelerated post-surgical rehabilitation protocol of immediate full weightbearing and no bracing or restriction to movement, allowing earlier restoration of rom before the start of the study and during baseline phases. the land-based rehabilitation protocol of emphasised knee extension immediately after surgery may explain why participants 2 and 3 obtained good extension before the start of the hydrotherapy. participant 1 demonstrated the greatest fig.1. koos score findings. 0 10 20 30 40 50 60 70 80 90 100 a1 a1 a1 b b b b b b a2 a2 a2 assessment period k o o s sc o re (% ) patient1 patient 2 patient 3 fig. 1. koos score findings. fig. 2. 6mwt findings (participant 3 missed one session). 200 250 300 350 400 450 500 550 600 650 700 a1 a1 a1 b b b b b b a2 a2 a2 assessment period 6m w t (m ) patient 1 patient 2 patient 3 fig. 2. 6mwt findings (participant 3 missed one session). fig.3. active knee flexion rom findings. 60 70 80 90 100 110 120 130 140 150 160 a1 a1 a1 b b b b b b a2 a2 a2 assessment period a ct iv e kn ee fl ex io n (d eg re es ) patient 1 patient 2 patient 3 fig. 3. active knee flexion rom findings. 1 fig. 4. active knee extension rom findings. -10 -8 -6 -4 -2 0 2 4 6 a1 a1 a1 b b b b b b a2 a2 a2 assessment period a ct iv e kn ee ex te n si o n (d eg re es ) patient 1 patient 2 patient 3 fig. 4. active knee extension rom findings. sajsm vol 20 no. 4 2008 113 114 sajsm vol 19 no. 4 2007114 sajsm vol 20 no. 4 2008 effect of treatment on knee extension measures. this may, however, be better explained by post-surgical maturation as this participant had the shortest baseline phase and all three participants obtained between 50% and 100% of maximum range by 4 weeks after surgery (fig. 4). although the multiple baseline design was applied to control for internal validity threats such as maturation, the effects of maturation could not be completely negated. study limitations the present study, due to its clinical nature, did not allow access to the kt-1000 (gold standard for determining graft stability) for objective determination of graft stability which is of obvious concern with the implementation of accelerated rehabilitation protocols after acl reconstruction. due to time constraints, long-term follow up of 6 months could not be done, and baseline phases were also kept to a minimum time period ranging from 4 to 18 days. long-term effects of accelerated hydrotherapy should therefore be investigated in future studies. participant satisfaction (though not investigated in this study) can be a good predictor of recovery and should be considered in future studies to explore the use of accelerated hydrotherapy in this patient population. clinical implications • accelerated hydrotherapy in addition to land-based rehabilitation is safe, feasible and well tolerated by participants. • there are some trends in the data to indicate that it has an extra beneficial effect on subjective measures of pain, function and qol (measured by the koos scale) over and above land-based rehabilitation. • clinicians should use this intervention with clear outcome measures to monitor individual effects until such time as there is a stronger evidence base for its effectiveness in sports persons after acl reconstruction. • further research into the use of hydrotherapy in this population, using larger sample sizes and higher-level methodology, is now warranted. conclusion it is essential that new approaches to management be studied in smaller case series to understand responses in outcomes prior to expensive, large-group intervention studies. this study’s findings indicate that accelerated hydrotherapy may be a useful and safe adjunct to an accelerated land-based programme after acl reconstruction. this study therefore provides an impetus for larger future experimental studies. acknowledgements dr vp gajjar (orthopaedic surgeon) is acknowledged for his participation and contribution to this study. references 1. beeson pm, robey rr. evaluating single-subject treatment research: lessons from aphasia literature. neuropsychol rev 2006; 16: 161-9. 2. biscarini a, cerulli g. modelling of the knee joint load in rehabilitative knee extension exercises under water. j biomech 2007; 40(2): 345-55. 3. brosseau l, balmer s, tousignant m, et al. intraand inter-tester reliability and criterion validity of the parallelogram and universal goniometers for measuring maximum active knee flexion and extension of patients with knee restrictions. arch phys med rehabil 2001; 82: 396-402. 4. chmielewski tl, hurd wj, rudolph ks, axe mj, snyder-mackler l. perturbation training improves knee kinematics and reduces muscle co-contraction after complete unilateral anterior cruciate ligament rupture. phys ther 2005; 85(8): 740-9. 5. fujimoto e, sumen y, urabe y, et al. an early return to vigorous activity may destabilise anterior cruciate ligament reconstructed with hamstring grafts. arch phys med rehabil 2004; 85(2): 298-302. 6. heller l, martin k. wta tour: aquatic therapy for tennis. med sci tennis 2003; 8(1): 8-9. 7. hengeveld e, banks k. maitland’s peripheral manipulation, 4th ed. london: butterworth heinemann, 2005: 89-124. 8. kennedy dm, stratford pw, wessel j, gollish jd, penney d. assessing stability and change for four performance measures: a longitudinal study-evaluating outcome following total hip and knee arthroplasty. bmc musculoskelet disord 2005; 6(1): 3. 9. kuehne c, zirkel a. accelerated rehabilitation following patellar tendon autograft anterior cruciate ligament reconstruction using the aqua-jogging protocol: a primary study. sports exerc injur (edinburgh, scotland) 1996; 2(1): 15-23. 10. macdonald pb, hedden d, pacin o, huebert d. effects of an accelerated rehabilitation program after anterior cruciate ligament reconstruction with combined semitendinosus-gracilis autograft and a ligament augmentation device. am j sports med 1995; 23(5): 588-592. 11. miyoshi t, shiroto t, yamamoto s-i, nakazawa k, akai m. functional roles of lower limb joint moments while walking in water. clin biomech (bristol avon) 2005; 20(2): 194-201. 12. miyoshi t, shiroto t, yamamoto s-i, nakazawa k, akai m. lower limb joint moment during walking in water. disabil rehabil 2003; 25(21): 1219-23. 13. muneta t, sekiya i, ogiuchi t, yagishita k, yamamoto h, shimomiya k. effects of aggressive early rehabilitation on the outcome of anterior cruciate ligament reconstruction with multistrand semitendinosus tendon. int orthop 1998; 22: 352-6. 14. poyhonen t, kyrolainen h, keskinen kl, hautala a, savolainen j, malkia e. electromyographic and kinematic analysis of therapeutic knee exercises under water. clin biomech (bristol avon) 2001; 16: 496-504. 15. poyhonen t, keskinen kl, kyrolainen h, hautala a, savolainen j, malkia e. neuromuscular function during therapeutic knee exercise under water and on dry land. arch phys med rehabil 2001; 82(10): 1446-52. 16. prins ja, cutner d. aquatic therapy in the rehabilitation of athletic injuries. clin sports med 1999; 18(2): 447-61. 17. roos em, roos hp, lohmander ls, ekdahl c, beynnon bd. knee injury and osteoarthritis outcome score (koos) – development of a self-administered outcome measure. j orthop sports phys ther 1998; 28: 88-96. 18. shelbourne kd, nitz p. accelerated rehabilitation after anterior cruciate ligament reconstruction. am j sports med 1990; 18(3): 292-9. 19. thalheimer w, cook s. how to calculate effect sizes from published research articles: a simplified methodology. retrieved 2008 from http:// work-learning.com/effect_sizes.htm. 20. thein jm, brody lt. aquatic-based rehabilitation and training for the elite athlete. j orthop sports phys ther 1998; 27(1): 32-41. 21. tovin bj, wolf sl, greenfield bh, crouse j, woodfin ba. comparison of the effects of exercises in water and on land on the rehabilitation of patients with intra-articular anterior cruciate ligament reconstructions. phys ther 2004; 74(8): 710-9. introduction rugby is a sport where size does matter. players who are bigger, stronger and faster have an advantage over smaller, less powerful players. these differences in size are exacerbated at the junior levels where players reach puberty at different stages. furthermore, the problem is compounded in south africa, where children from a low socio-economic environment are generally smaller and less powerful than their counterparts from more affluent areas. 1 there is a strong likelihood that the smaller talented players will rather participate in sports in which they can express their talent and not be limited by their lack of size, as is the case in rugby. some players in this group may be late developers, who possess the skills associated with success in rugby but lack the size. if these players are not managed appropriately, their superior skills may not ever have an opportunity to manifest and develop fully. this raises the point of having a wellconstructed long-term talent development model 2 which considers that talent development is multi-factorial and dynamic in nature. 3 such a model would consider the differences in size during puberty and cater as much for the slow developers as it does for the early developers. developing talent is not an easy task and requires ongoing monitoring to ensure that there are progressions in skill, physical ability and cognitive maturation. 3 failure to adopt a long-term talent development model, where talent and skills are developed systematically, will result in many players who may be late developers, choosing to play other sports where size is not such a distinguishing factor. this raises questions of whether rugby in south africa needs to be managed differently to cater for these smaller players, particularly during the pre-pubertal years, where most of the variation in size exists. 4 what about new zealand and australia? young players in australia and new zealand are managed differently to the way young players are managed in south africa. this can possibly be attributed to the fact that there are fewer rugby players in these countries compared with south africa. consider that south africa has over nine times the number of pre-teen players compared with australia, and nearly four times as many as occur in new zealand (table i). in south africa, the number of players decreases systematically with increasing age, with only 18% of the total number of male players being senior players (fig. 1). in new zealand the pattern of decline across age groups is similar to that which occurs in south africa (fig. 1). the pattern in australia is different to both the south african and new zealand pattern as there is a small decrease in the number of players from the pre-teens to teen categories and then the numbers increase substantially from teens to seniors (fig. 1). even with this attrition south africa has 2.3 times as many senior players as australia and 3.1 times as many players compared to new zealand (table i). these data can be interpreted in one of two ways. either the australian model attracts senior players to the sport, possibly through the other rugby codes which exist in australia (rugby league and australian rules football), or the junior talent which exists in australia is managed and developed more efficiently compared with the south african model, and to a lesser extent the new zealand model. another interpretation of the patterns between the three countries is that because there are so many players in south africa (i.e. 9.4 and 3.7 times as many pre-teen players as in australia and new zealand respectively), the talent does not have to be managed as carefully as it does in australia and new zealand. by applying the principle of ‘survival of the fittest’, the best players make it through to the senior ranks in the south african system. however, with fewer players in both australia and new zealand, the importance of ensuring that they are well managed increases. a closer inspection of the talent development models of australia and new zealand reveals that this is indeed the case. australian model junior players in australia are exposed to rugby in a progressive way as part of a junior player pathway development strategy. 6 there are commentary long-term player development in rugby – how are we doing in south africa? correspondence: professor mike lambert po box 115 newlands 7725 tel: 021-650 4558 e-mail: mike.lambert@uct.ac.za mike i lambert1 (phd) justin durandt2 (bsc (med hon) exercise science (biokinetics)) 1 mrc/uct research unit for exercise science and sports medicine, department of human biology, university of cape town 2 discovery high performance centre, sports science institute of south africa table i. registered male players (pre-teen, teens and adults) in south africa, new zealand and australia5 age group south africa new zealand australia pre-teens 239 614 63 924 25 609 teens 148 779 40 257 20 002 senior 84 522 27 203 37 179 total 472 915 131 384 82 790 sajsm vol 22 no. 3 2010 67 three categories of age groups, each with different rules and adaptations to the game: • walla rugby (7 8 years) – the game is played on a smaller field, with seven players per team and there is no tackling. the rules are designed to develop the game principles of possession, ‘go forward’ and pressure. the individual skills of passing and receiving, running and evasion, scrumming and line-outs are developed. • mini rugby (9 10 years) – the principles of walla rugby are maintained, but the players are all introduced to the contact aspects of the game. the game is also played on a smaller field with 10 players in each team. • midi rugby (11 12 years) – this is the transition into the full game. there are 12 or 15 players on a standard size field. from the age of 13 years the players are introduced to the game played under full rules. the australian rugby union maintains that the junior player pathway provides children with a safe and enjoyable introduction to the skills and practical principles of the game of rugby. 6 the gradual exposure to the skills is appropriate for their age. physical development, size and body shape is not as important in this form of the game. new zealand model the new zealand rugby union has developed small blacks rugby which is designed to help players develop their skills as their physical ability develops. 7 the intention is to make the game safe regardless of the player’s age, shape or size. at the under-7 level there are 7 players per team and they play on a smaller field with no tackling allowed. at this level they also play rippa rugby which is a safe, noncontact game for boys and girls. this game is designed to improve ball handling and running skills. 7 from 8 to 10 years there are only 10 players per team and this game is also played on a smaller field. they are introduced to tackling, but players are not allowed to fend off a tackle. there is also a rule that if there is total dominance of one team (i.e. 35 points or more at half time) the coaches consult on a strategy which will even the competition in the second half. from the age of 10 13 years they play with 15 players per team on a full-size field and have modified rules (i.e. limited pushing in the scrum, no lifting in the line-outs). this development programme is designed to provide the players with skills so that when they play the full game they are suitably trained. 7 south african model although various provinces have implemented games for juniors with adjusted rules to cater for smaller players, there is no co-ordinated programme in south africa. a programme which is gaining momentum in south africa is tag, which is played in about 300 schools around the country. 8 in this game there are no scrums and line-outs and tackling are not allowed. the aim of the game is to allow children to develop skills for rugby in a safe, fun environment. however, for this to serve the national game and prepare youth adequately for fullcontact rugby it needs to be co-ordinated nationally. summary a long-term talent development model in rugby similar to those practised by australia and new zealand makes sense because these models are dynamic and consider the maturity status and level of development of the young players, with the overall result of being more inclusive for players of all sizes rather than exclusive for smaller players. however, this approach will require a major paradigm shift in south africa, and may take some time to implement. failure to address the problem of significant body size mismatches in youth rugby in south africa will result in a continuance of the current player attrition rate that is much larger than that which exists in other major rugby playing nations. while south africa has a large pool of players to draw from, and therefore is less affected by the attrition of players, there is no guarantee that this situation will remain the same in the future. if the pool of players decreases, the implementation of a longterm player development model will be even more crucial because the talent will then become a treasured commodity. acknowledgments the contents of this paper were extracted and modified from a paper which was commissioned by the boksmart programme. this is a national programme sponsored by absa and implemented on behalf of the south african rugby union and the chris burger/petro jackson player’s fund. the goal of the programme is to teach safe and effective techniques which will reduce the incidence and severity of injury, make the game safer for all involved and improve rugby performance. references 1. armstrong me. youth fitness testing in south african primary school children: national normative data, fitness and fatness, and effects of socioeconomic status. phd thesis, university of cape town, 2009. 2. vaeyens r, lenoir m, williams am, philippaerts rm. talent identification and development programmes in sport : current models and future directions. sports med 2008;38(9):703-714. 3. burgess dj, naughton ga. talent development in adolescent team sports: a review. int j sports physiol perform 2010;5(1):103-116. 4. lambert mi, brown j, forbes j. skeletal development and the associated risk of catastrophic head, neck and spine injury. www boksmart com 2010;1-23. 5. international rugby board. website 2010available from: url: http://www. irb.com/ 6. australian rugby union. website 2010available from: url: www.rugby.com. au/community_rugby/playing_rugby/playing_rugby_landing_page,77260. html 7. new zealand rugby union. website 2010available from: url: http://www. nzrugby.co.nz/smallblacks/tabid/933/default.aspx 8. tag rugby association. website 2010available from: url: www.tagrugby. co.za so ut h af ric a ne w ze al an d au st ra lia 0 20 40 60 pre-teens teens senior p er ce n t fig. 1. percentage of the total number of players (pre-teens, teens and seniors) in south africa, new zealand and australia.5  fig. 1. percentage of the total number of players (preteens, teens and seniors) in south africa, new zealand and australia. 5 68 sajsm vol 22 no. 3 2010 case report 1 sajsm vol. 29 2017 the forgotten coracoid: a case report of a coracoid fracture in a male cyclist e duinslaeger, 1,3,4 md; j h kirby, 1,2,3 mbchb, msc (sports med); j t viljoen, 1,2,3 bsc (physio), mphil (exercise sci); p l viviers, 1,2,3 mbchb, mmedsc, msc (sports med), facsm 1 institute of sport and exercise medicine, stellenbosch university, south africa 2 international olympic committee research centre, cape town, south africa 3 campus health service, stellenbosch university, south africa 4 department of physical medicine and rehabilitation, catholic university of leuven, belgium corresponding author: p viviers (plviviers@sun.ac.za) case report a healthy 48-year-old male elite triathlete injured his right shoulder during a descent while mountain-biking. his front wheel hit an obstruction causing him to be catapulted over the handlebars and he landed on his shoulder. he experienced immediate pain, swelling and dysfunction of the shoulder. on further evaluation there was visible swelling of the superior and anterior aspects of the shoulder without gross deformity. there was diffuse tenderness on palpation, and both active and passive mobilisations were painful. clinical suspicion was that of an acromioclavicular (ac) joint injury. patient consent for use of these data in this clinical case presentation was obtained. plain film radiographs revealed a cranial subluxation of the distal clavicle on the neutral view, as well as small bony fragments in the proximity of the coracoid but without an identifiable fracture. the 15° tilt view did not demonstrate a widening of the ac joint (figure 1a). due to the disproportionate pain experienced by the athlete, imaging was followed up with a computed tomography (ct) and magnetic resonance imaging (mri not shown in this report), using t1, t2 and fat saturated sequences. the mri revealed a type ii ac injury (according to the rockwood classification) [1] with oedema of the coracoclavicular ligament and an intact coracoacromial ligament. a fat-fluid level was present in the subacromial bursa and the ct scan demonstrated a splayed fracture of the base of the coracoid process measuring 7.4 mm with 21°of angulation (figure 1b). in addition to the ac joint subluxation and coracoid fracture, a fracture of the transverse process of the right fifth lumbar vertebra was detected. conservative management included the use of paracetamol and a shoulder sling for four weeks with the arm in adduction and the elbow in 90°of flexion. following this period of treatment, the patient was still not pain-free and had restricted range of motion. follow-up ct scans at eight weeks showed callus formation without full union. at 10 weeks post injury, rehabilitation, including shoulder stabilisation exercises and mobilisation, was commenced. running and cycling were resumed; however, swimming was delayed to protect the ac joint. at one year, the shoulder had full range of motion and activities of daily living were pain-free. discussion the coracoid process is a key connection between the scapula and the clavicle and an important anchor in the coracoacromial arch; it is part of the superior shoulder suspensory complex (sssc) as proposed by goss et al. [2] the sssc is a ring formed by the glenoid process, the coracoid process, the coracoclavicular ligaments, the distal clavicle, the acromioclavicular joint and the acromial process (figure 1c). it is strutted superiorly by the middle clavicle and inferiorly by the lateral scapula. a disruption of any one of these structures tends to be a minor injury without compromising of the shoulder complex. conversely, when the complex is disrupted at two different sites, it becomes anatomically unstable leading to longer healing periods and functional consequences. a double disruption of the sssc with unacceptable displacement is considered an indication for surgical intervention. [2] coracoid fractures are uncommon, and account for 1% of all fractures and 3-13% of scapula fractures in the general population. these fractures have not been previously reported in cycling. the precipitating event is typically a a fall onto the shoulder is a common mechanism of injury in cyclists. however, coracoid fractures remain unreported in the literature in this population. these authors report a case of a coracoid fracture missed on the initial plain film radiographs. whilst these fractures can be easily missed on standard trauma series radiographs of the shoulder, alternate views and other imaging modalities can be used to detect these fractures. clinical suspicion, judicious imaging and accurate diagnosis of these fractures are important, as stability of the coracoid influences the entire superior shoulder suspensory complex which allows normal function of the shoulder joint keywords: cycling, trauma, sport, injury, shoulder injury s afr j sports med 2016; 29:1-2. doi: 10.17159/2078-516x/2017/v29i0a1636 http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1636 case report sajsm vol. 29 2017 2 direct blow to the lateral shoulder (being thrown over the handlebars); however, this mechanism more commonly causes ac joint injuries and clavicle fractures; which are reported as the most frequent traumatic injuries in cycling.[3] the possible mechanisms leading to the fracture are coracoclavicular ligament avulsion during an ac dislocation; a direct blow to the process, or extremely forceful contraction of the biceps and/or the pectoralis minor muscles. associated injuries are among others acromial fractures, glenohumeral dislocations, clavicle fractures and ac joint dislocations. [4] according to haapamaki et al. the diagnosis of coracoid injuries is frequently missed; [5] however, a lack of organised epidemiological reporting of injuries within the cycling fraternity may contribute to this observation. plain film radiography is the first-line imaging modality; however, the coracoid process is difficult to visualise with routine views due to the superimposed structures. the sensitivity of primary radiography (ap-view, scapular y and axial projection) in the diagnosis of coracoid fractures is 40%, making these fractures the most occult of the scapula fractures. moreover, due to associated injuries, the focus of attention is drawn away from the coracoid. [5] likewise, in this case the coracoid base fracture was missed on initial radiographs. to improve diagnostic accuracy, the stryker notch view is recommended as the scapular y view sensitivity is poor. [5] the significance of making an accurate diagnosis of a coracoid fracture would allow the clinician to assess the stability of the shoulder complex, and to institute the correct treatment plan bearing in mind the associated injuries. this would in turn facilitate a quicker return to functionality without secondary consequences, such as nonunion, malunion, coracohumeral impingement or shoulder instability.[2, 6] in conclusion, a typical fall onto the shoulder could result in a coracoid fracture. these fractures are frequently overlooked on standard x-ray views but can be more easily demonstrated in a cephalad-tilted view or an adapted stryker notch view, which is useful in this setting. with this case the authors would like to encourage clinicians and radiologists to actively exclude coracoid fractures with appropriate careful examination and specific radiological views. the shoulder consists of an intricate suspensory complex and therefore the complete assessment of all these structures is important to formulate an accurate diagnosis and appropriate treatment plan in order to avoid delayed healing and further negative functional consequences. acknowledgements: the authors would like to thank winelands radiology for the images. references 1. rockwood ca, matsen fa,wirth ma,et al. the shoulder. vol.1. 4th ed.. philadelphia: wb saunders, 1990:533-537. 2. goss tp. double disruptions of the superior shoulder suspensory complex. j orthop trauma 1993;7(2):99–106. [http://dx.doi.org/10.1097/00005131-199304000-00001] pmid:8459301 3. silberman mr. bicycling injuries. curr sports med rep2013 sepoct;12(5):337–345. [http://dx.doi.org/10.1249/jsr.0b013e3182a4bab7] pmid:24030309 4. ogawa k, yoshida a, takahashi m,et al. fractures of the coracoid process. j bone joint surg br 1997 jan;79(1):17–19. [http://dx.doi.org/10.1302/0301620x.79b1.6912] pmid:9020438 5. haapamaki vv, kiuru mj, koskinen sk. multidetector ct in shoulder fractures. emerg radiol 2004 dec;11(2):89–94. [http://dx.doi.org/10.1007/s10140-004-0376-x] pmid:155174535. 6. gerber c, terrier f, ganz r. the role of the coracoid process in the chronic impingement syndrome. j bone joint surg br 1985 nov;67(5):703–708. pmid:40558642011;127(3):511-528. [http://dx.doi.org/ 10.1542/peds.20093592] g a a a a b c a b c fig. 1a. anteroposterior x-ray view of right shoulder shows a cranial subluxation of distal clavicle without identifiable fracture. fig. 1b. computed tomography scan showing a basal fracture of the coracoid process. fig. 1c. 3d ct images of sssc ring (circle) with ac dislocation and basal coracoid fracture (arrows). sajsm vol. 25 no. 2 2013 43 background. the potential performance-enhancement effect of pseudoephedrine (pse) use has led to its prohibition in competition sports (urine concentrations >150 µg/ml). data are, however, scarce regarding whether therapeutic pse use enhances swimming performance. objective. to investigate the effect of therapeutic pse use on performance in aerobic and explosive sprint swimming events. method. a double-blinded cross-over study design was used. participants in the control group initially received a placebo and those in the experimental group received a divided pse dose of 90 mg/d. anaerobic power (50 m sprint) and aerobic (2 000 m) swimming testing was conducted at (i) baseline; (ii) after ingestion of a placebo or pse; and (iii) after the groups were crossed over, following a wash-out period of 4 days, to determine changes in performance between trials. results. the participants (mean age 44 years; n=7) were competitive masters swimmers with normal resting heart rates (68 beats per minute (bpm); standard deviation (sd) ±14) and blood pressures (bps) (171 (sd ±27)/83 (sd ±16) mmhg). the use of pse during the anaerobic swim test showed only a trivial chance (68%) of improvement, with a likely enhancement in systolic bp (86%). the aerobic swim test did not affirm performance enhancement as measured by time to completion (52% chance of a positive effect; 41% chance of a negative effect), nor did any other physiological variable of interest (peak heart rate and exercising bp) differ significantly from baseline results. conclusion. the use of a therapeutic amount of pse in short and endurance swimming trials did not appear to have any major ergogenic effect on performance. s afr j sm 2013;25(2):43-46. doi:10.7196/sajsm.378 effect of a therapeutic dose of pseudoephedrine on swimmers’ performance p j-l gradidge,1 msc (med) (biokinetics); d constantinou,1 mb bch, bsc med (hons), ffims; s-m heard,1 bhsc (hons) (biokinetics); c king,1 bhsc (hons) (biokinetics); h morris-eyton,2 med (adult education) 1 centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 school of education, faculty of humanities, university of the witwatersrand, johannesburg, south africa corresponding author: p j-l gradidge (philippe.gradidge@wits.ac.za) mailto:philippe.gradidge@wits.ac.za 44 sajsm vol. 25 no. 2 2013 pseudoephedrine (pse) is a sympathomimetic substance found in over-the-counter (otc) products such as nasal decongestants, and in respiratory medicines in combination with antihistamines.[1] the action of sympathomimetic substances mimics that of epinephrine and norepinephrine, acting mainly on the αand β-adrenoreceptors.[2] the ingestion of pse results in the release of norepinephrine from storage sites in nerve and neural tissue.[2] this is thought to result from direct stimulation of post-synaptic receptors and inhibition of neurotransmittor reuptake.[3] it is also hypothesised that pse has ionoand chronotropic effects on the heart and that it increases the exercising heart rate (hr), resulting in greater venous return and cardiac output.[2,3] the latter is thought ultimately to result in increased oxygenated blood supply to the exercising muscles, reducing the premature onset of muscle fatigue. the total torque production of the muscles is consequently increased and may result in enhanced athletic performance.[2,3] these and other positive effects of pse appeal to athletes, although doses ≥240 mg (above therapeutic doses) may be needed for a positive ergogenic effect.[4,5] literature on the effectiveness of pse as a performance enhancer is conflicting. some studies have shown that pse use improves 1 500 m running times, maximal torque in isometric knee extension, peak power during maximal cycling performance and lung-function capacity.[2,6] on the contrary, other studies have shown that therapeutic doses of pse have no effect on cycling performance, 5 000 m endurance running, handgrip max imal voluntary contraction, time to fatigue, and peak mean total power output during anaerobic cycling.[1,3,5] the world antidoping agency (wada) decided to prohibit pse use in sport because of evidence that it does, or has the potential to enhance performance;[7,8] however, confirmation of the ergogenic effect is limited and therapeutic use of pse as a potential performance enhancer has only been examined in a small number of studies. furthermore, research on its use in swimmers is limited. the purpose of this study was therefore to investigate the effect of the therapeutic use of pse on swimming performance in aerobic and anaerobic (explosive sprint) swimming events. methods we used a double-blinded, randomised, controlled cross-over trial design of repeated measures. ethical approval of the study was granted by the university of the witwatersrand (m1100445). participants male and female masters-level swimmers competing in swimming events were invited to participate in the study (n=7). inclusion criteria included an appropriate level of swimming, age 25 60 years (as defined by the federation internationale de natation (fina)[9]), a training frequency of ≥3 days per week, and a minimum of 2 years of swimming experience in masters-level competitive swimming events. exclusion criteria included a history of or current cardiac disease, congenital defects, hypertension or renal disease; recent illness; the presence of musculoskeletal injury; and the existing use of performance-enhancing substances or recreational drugs. participants were initially randomly assigned to an experimental group (pse) or a control group (placebo). they were then asked to perform anaerobic power (50 m sprint) and aerobic (2 000 m) swim tests at (i) baseline; (ii) after ingestion of the placebo or pse; and (iii) after the groups were crossed over, following a wash-out period of 4 days, to determine changes in performance between trials. to prevent a trained performance increase, the swimmers were asked to maintain their training regimens during the testing period. their diets remained the same, except that they were asked to avoid caffeine, alcohol, nicotine and other stimulant drugs for 24 hours prior to testing. anthropometrical measurements resting and post-exercise hrs were measured using the radial pulse after a 5 10-minute resting period with participants seated. [10] resting blood pressure (bp) was then measured using an aneroid sphygmomanometer and accompanying stethoscope (delux (kt-102) rappaport, hi-care). bp was recorded immediately after the aerobic and anaerobic swim tests.[10] height was measured using a stadiometer. [10] weight was measured to the nearest kg with participants dressed in minimal clothing and with shoes removed (seca, germany). following baseline measurements, the participants were randomly assigned to the control and experimental groups. after a warm-up period to which they were individually accustomed, the participants were asked to perform the baseline aerobic and anaerobic swimming tests. the post-exercise hr, bp, rate of perceived exertion (rpe) (using the borg 1-10 rpe scale)[10] and time taken to perform the tests (econosport 240 stopwatch, sportline) were recorded by the same researcher. swimming performance tests although the participants were familiar with the test protocols, and therefore knowledgeable regarding procedural expectations, the protocols were fully explained before each testing session to confirm full comprehension of participant requirements. baseline testing served to acquaint the participants with the tests, and the results thereof allowed for comparison with the subsequent swim tests. the first test involved an anaerobic power activity, with participants required to give maximal effort in a 50 m sprint (2 lengths of a standard 25 m pool). the second swim test comprised a timed 2 km aerobic swim, again required to be performed with maximal effort.[5] in the latter, the best time taken for the swimmer to complete the test was recorded, and the researchers counted the number of laps performed.[1] the tests were conducted at different swimming pools as participants belonged to different swim clubs; however, the aerobic and anaerobic tests were conducted in the same swimming pool per participant. likewise, the tests were conducted at the same time of day per participant. to keep procedures consistent, the swimmers were required to start tests in the swimming pool and push off the pool wall. hr and bp were recorded before and immediately after each test. no verbal encouragement was given to participants to ensure consistency in this regard throughout testing. participants were not given individual results, and were reminded that the data were analysed per group. placebo and pse administration after baseline data collection, each swimmer received either the placebo (no active ingredient) or 30 mg of pse (sudafed, pfizer) 3 times daily for 4 days (to ensure a therapeutic dose). the researchers and participants were blinded to which drug each group received. a sufficient supply of tablets for 4 days was administered to each participant by a research assistant. the placebos and active drugs were coded by independent persons, allowing for decoding at the end of the study. sajsm vol. 25 no. 2 2013 45 to improve compliance, the participants received a daily text message via mobile phone, reminding them to ingest the tablet at the correct time of day. after taking the treatment for 4 days, the swimmers were tested in the same manner as for baseline testing. a wash-out period of 4 days was then observed to allow for complete elimination of the substances. the participants were subsequently crossed over, and the same procedures followed after ingestion of the opposite treatment (i.e. placebo or pse). statistical analysis descriptive statistics were used for demographic data. non-parametric statistics were used, as data were not normally distributed and the sample size was small (n=7). the friedman analysis of variance (anova) with kendall co-efficient of concordance was used to measure the association between paired samples using statistica (version 10). paired t-tests were done to determine the effect statistic and p-value for each variable of interest. the magnitude of difference was calculated accordingly to determine if changes were ‘positive’, ‘trivial’ or ‘negative’ according to batterham and hopkins[11] (a probability was ascribed to each magnitude). cohen’s d was used to determine effect size between placebo and pse use. results seven masters-level competitive swimmers participated in the investigation. participant demographics and baseline data are displayed in table 1. the mean age (44 years; standard deviation (sd) ±7) represented a typical team at the masters stage of a swimming career. the swim times in the 50 m and 2 000 m protocols did not change in a meaningful way, reflected by the small effect sizes (d=0.18 0.06) and the magnitude inferences (%positive/trivial/negative effects) of %52/8/41 and %25/68/8, respectively (table 2). hr did not change significantly in the 50 m time trial, but was likely to have increased in the 2 000 m swim (%85/6/9). this is supported by the small to moderate effect size shown in both tests (d=0.3 0.5). the majority of the other findings had effect sizes that were small; however, diastolic blood pressure (dbp) had medium effect sizes in the anaerobic and aerobic swim tests (d=0.76 and 0.56, respectively). the rpe during all trials was near maximal effort, as was requested of the participants, and did not change significantly throughout (small effect size; d=0.2). finally, there may have been a likely change in systolic blood pressure (sbp) in the 50 m sprint (%86/11/3) and 2 000 m time trial (%76/17/7). discussion athletes are continually looking for ways to enhance their performance in order to gain a competitive advantage in sport; and anti-doping organisations such as wada are continually trying to keep abreast of these means.[12] some athletes use well-known otc medicines that have been prohibited as they have been shown to enhance performance.[3,12] others, to aid with recovery and training, consume nutritional supplements that are potentially contaminated, knowingly or inadvertently, with prohibited substances.[13] in both cases, the athlete could be sanctioned if doping tests are positive; the former scenario being of particular concern, as pse can be found in nasal decongestants and respiratory medicines in combination with antihistamines.[1] a recently published position statement argued that although otc substances such as pse could potentially augment performance, these products could cause long-lasting harm to athletes and should therefore table 2. anaerobic swim test results for the 50 m and 2 000 m swim protocols (n=7) testing variable baseline mean (±sd) placebo mean (±sd) pse mean (±sd) friedman anova (p-value) kendall coefficient of concordance effect size positive* % trivial* % negative* % 50 m swim protocol time (s) hr (bpm) sbp (mmhg) dbp (mmhg) rpe 38.8 (±5.6) 119 (±24) 171 (±27) 89 (±16) 7.1 (±2.6) 38.7 (±5.5) 126 (±35) 175 (±27) 77 (±8) 7.7 (±2.1) 38.6 (±5.4) 122 (±25) 161 (±27) 80 (±8) 7.9 (±1.6) 0.92 (0.6) 0.27 (0.9) 3.2 (0.2) 4.6 (0.1) 1.9 (0.4) 0.7 0.02 0.2 0.3 0.1 0.18 0.30 0.68 0.76 0.16 25 56 86 1 1 68 35 11 99 99 8 9 3 0 0 2 000 m swim protocol time (s) hr (bpm) sbp (mmhg) dbp (mmhg) rpe 1 993 (±550) 117 (±9) 166 (±26) 77 (±8) 6.9 (±2.5) 2 091 (±392) 135 (±33) 170 (±23) 74 (±6) 6.9 (±2.40) 2 079 (±319) 109 (±45) 157 (±28) 75 (±5) 7.1 (±2.1) 1.14 (0.6) 1.56 (0.5) 1.18 (0.6) 0.56 (0.8) 0.95 (0.95) 0.08 0.11 0.08 0.04 0.007 0.06 0.50 0.47 0.56 0.21 52 85 76 0 1 8 6 17 100 93 41 9 7 0 5 pse = pseudoephedrine; anova = analysis of variance; sd = standard deviation; hr = heart rate; sbp = systolic blood pressure; dbp = diastolic blood pressure; rpe = rate of perceived exertion. *values are rounded and therefore may not add up to 100% exactly. table 1. summary of sample characteristics (n=7) variable mean (±sd) height (m) 1.76 (±7.30) weight (kg) 88 (±14) bmi (kg/m2) 28.6 (±3.3) resting hr (bpm) 68 (±14) sbp (mmhg) 129 (±12) dbp (mmhg) 80 (±10) sd = standard deviation; bmi = body mass index; hr = heart rate; sbp = systolic blood pressure; dbp = diastolic blood pressure. 46 sajsm vol. 25 no. 2 2013 be avoided if suspicion is warranted.[14] nevertheless, the time taken for optimal effect could be extensive with the use of nutritional supplements; therefore, they are not as appealing as the faster-acting pse.[15] pse is banned in-competition, due to its potentially ergogenic effect on athletes in theoretical urine concentrations >150 µg/ml, even though evidence of its effect in athletes is limited.[7,8] in our study, performance was measured after a 4-day period of ingestion of 90 mg/d of pse – an amount sufficient to cause a substantial increase in urine concentration. furthermore, performance was tested in both sprint and long-distance events. however, the findings showed no likely enhancement in the majority of variables tested, with the exception of a probable increase in hr in the 2 000 m swim trial (positive/trivial/negative: 85/6/9) with a small effect size (d=0.1). the rpe subjectively measured effort level of performance, and it was ensured that the tests were conducted at high intensity (rpe ≥6). the tests were performed using pse and placebo in indiscriminate order initially, with these substances switched after a 4-day wash-out period. there were slight improvements in swim time with the use of pse in the 50 m and 2 000 m events; however, the probabilty that these changes were meaningful was low (25% and 52%, respectively). of interest was the reduction in sbp in both tests with pse use; an acute, but unexpected effect. this is contrary to a similar study by chester et al.,[4] which did not show a significant change in sbp or dbp during endurance running, even with use of a higher treatment dose of pse (240 mg). similarly, hunter et al.[16] reported no influence on performance in a cycling time trial with the use of 120 mg of pse 2 hours prior to testing. in our study, the greatest effect size was observed in dbp during the 50 m sprint, but the magnitude of this effect was almost certainly trivial (99%). the results of our study support that therapeutic pse use does not convey quantifiable benefits during explosive anaerobic events, although the sporting discipline of our study differed from that of the aforementioned, which utilised either prolonged[16] or endurance[4] testing protocols. likewise, enhancement of performance was not evident in endurance events in our study. on the other hand, some studies have shown performance enhancement with pse use. hodges et al.[6] showed an improvement in running time (2.1%; p=0.001) among athletes, with no effect on hr. apart from investigating performance in a different sport (running v. swimming in our study), the study recruited elite athletes and employed a higher dose of pse (180 mg v. 90 mg in our study). the ingestion of higher than therapeutic (>120 mg) amounts of pse may lead to increased performance, as seen in a number of other studies. [1,6] for instance, pritchard-peschek et al.[17] reported a 5.1% increase in time trial cycling performance with the ingestion of 180 mg of pse. the researchers attributed the improvement to stimulation of the central nervous system or alterations in metabolism, but these cannot be proven without appropriate biochemical investigations. in the same way, another study by gill et al.,[2] which saw participants ingest 180 mg of pse, showed an improvement in anaerobic cycling and isometric knee extension, and contrary to the present study, a significant change in hr (p<0.001). interestingly, there were no reported adverse effects.[2] these studies support the theory that higher doses of pse may result in enhanced performance time, which may be of relevance in swimming competitions, warranting further investigation. improvements could be made for future studies in this area. firstly, a larger sample size should be used to substantiate the findings to a more comprehensive population. secondly, future studies should include different swimming populations and should measure blood and urine concentrations of the therapeutic dosage of pse, with the clear purpose of examining the relationship with performance. thirdly, the swimming pool size was consistent, but the location differed. the use of one swimming pool with controlled environmental factors would ensure consistency throughout testing. the warm-up used prior to testing – which varied between participants in our study, according to what they were accustomed – could be standardised for prospective studies. conclusion in our study, a therapeutic dose of pse (90 mg/d) did not show statistically significant effects on hr, sbp, swim times and rpe when ingested in therapeutic doses by masters-level swimmers. however, when the magnitude of these differences was examined, there was a relatively high probability of a decreased sbp in the 50 m sprint and decreased hr and sbp in the 2 000 m swim associated with the use of pse. nevertheless, an ergogenic advantage does not seem to be gained from the recommended therapeutic dose of pse (<120 mg/d) in endurance and sprint swimming performance. references 1. hodges anh, lynn bm, bula je, et al. effects of pseudoephedrine on maximal cycling power and submaximal cycling efficiency. med sci sports exerc 2003;35:13161319. [http://dx.doi.org/10.1249/01.mss.0000078925.30346.f8] 2. gill nd, shield a, blazevich aj, zhou s, weatherby rp. muscular and cardiorespiratory effects of pseudoephedrine in human athletes. br j clin pharmacol 2000;50:205-213. [http://dx.doi.org/10.1046/j.1365-2125.2000.00252.x] 3. chu ks, doherty tj, parise g, milheiro js, tarnopolsky ma. a moderate dose of pseudoephedrine does not alter muscle contraction strength or anaerobic power. clin j sport med 2002;12:387-390. 4. chester n, reilly t, mottram dr. physiological, subjective and performance effects of pseudoephedrine and phenylpropanolamine during endurance running exercise. int j sports med 2003;24:3-8. [http://dx.doi.org/10.1055/s-2003-37193] 5. salo d, riewald sa. complete conditioning for swimming. 1st ed. illinois, usa: human kinetics, 2008. 6. hodges k, hancock s, currell k, hamilton b, jeukendrup ae. pseudoephedrine enhances performance in 1500 m runners. med sci sports exerc 2006;38:329-333. [http://dx.doi. org/10.1249/01.mss.0000183201.79330.9c] 7. world anti-doping agency. the 2012 prohibited list world anti-doping code. montreal: world anti-doping agency, 2011. 8. pokrywka a, tszyrsznic w, kwiatkowska dj. problems of the use of pseudoephedrine by athletes. int j sports med 2009;30:569-572. [http://dx.doi.org/10.1055/s-0029-1202826] 9. federation internationale de natation (fina). masters rules. lausanne: fina, 2010. http://www.fina.org (accessed 9 november 2012). 10. american college of sports medicine (acsm). acsm’s guidelines for exercise testing and prescription. 8th ed. philadelphia, usa: lippincot williams & wilkins, 2010. 11. batterham a, hopkins w. making inferences about magnitudes. int j sports physiol perform 2006;11(1):50-57. 12. gradidge p, coopoo y, constantinou d. attitudes and perceptions towards performance-enhancing substance use in johannesburg boys high school sport. south african journal of sports medicine 2010;22(2):32-36. 13. van der merwe pj, grobbelaat e. inadvertent doping through nutritional supplements is a reality. south african journal of sports medicine 2004;16:3-7. 14. buell jl, franks r, ransone j, powers me, laquale km, carlson-phillips a. national athletic trainers’ association position statement: evaluation of dietary supplements for performance nutrition. j athl train 2013;48(1):124-136. [http://dx.doi. org/10.4085/1062-6050-48.1.16] 15. gradidge p, coopoo y, constantinou d. prevalence of performance-enhancing substance use by johannesburg male adolescents involved in competitive high school sports. archives of exercise in health and disease 2011;2(2):114-119. [http://dx.doi. org/10.5628/aehd.v2i2.102] 16. hunter g, derman we, noakes td, smith p, evans a, gabriels g. pseudoephedrine is without ergogenic effects during prolonged exercise. j appl physiol 1996;81(6):2611–2617. 17. pritchard-peschek kr, jenkins dg, osborne ma, slater gj. pseudoephedrine ingestion and cycling time-trial performance. int j sport nutr exerc metab 2010;20:132-139. http://dx.doi.org/10.1249/01.mss.0000078925.30346.f8] http://dx.doi.org/10.1046/j.1365-2125.2000.00252.x] http://dx.doi.org/10.1055/s-2003-37193] http://dx.doi.org/10.1249/01.mss.0000183201.79330.9c] http://dx.doi.org/10.1249/01.mss.0000183201.79330.9c] http://dx.doi.org/10.1055/s-0029-1202826] http://www.fina.org http://dx.doi.org/10.4085/1062-6050-48.1.16] http://dx.doi.org/10.4085/1062-6050-48.1.16] http://dx.doi.org/10.5628/aehd.v2i2.102] http://dx.doi.org/10.5628/aehd.v2i2.102] sajsm cpd instructions 1. read the journal. all the answers will be found there. 2. go to www.mpconsulting.co.za to asnwer questions. accreditation number: mdb001/015/01/2014 (clinical) true or false effective in 2014, the cpd programme for sajsm will be administered by medical practice consulting: cpd questionnaires must be completed online at www.mpconsulting.co.za a maximum of 3 ceus will be awarded per correctly completed test. june 2014 body composition and dietary intake of the fnb maties varsity cup rugby players 1. the varsity cup rugby forwards had an average body mass index (bmi) of 32.5, showing that they were all obese. 2. the varsity cup rugby players had the same body composition compared with national and international rugby players. 3. the varsity cup rugby players as a group had an inadequate intake of total energy, carbohydrate, polyunsaturated fatty acids, calcium:protein ratio and copper. 4. the varsity cup rugby players as a group had higher-thanrecommended values for total protein, fibre, total fat, saturated fatty acids, cholesterol and niacin. 5. the macronutrient intake of the rugby players >2 hours before the rugby game was adequate for energy and carbohydrate intake, but high in protein and fat intake. effect of caffeine ingestion on fluid balance during exercise in the heat and during recovery 6. athletes have been advised to abstain from caffeine during exercise because of its diuretic effect. 7. moderate caffeine ingestion (mean 460 mg) altered urine production during and after exercise. 8. three to four cups of regular brewed coffee would not place healthy young individuals at higher risk of hypohydration. 9. there is approximately 150 mg caffeine per 150 ml coffee. associations of physical activity with trabecular and cortical bone properties in prepubertal children 10. two of the most common physical activity assessments used for research purposes are maximum oxygen consumption (vo2 max) tests and physical activity questionnaires. 11. in this study, peak bone strain score was significantly associated with spine, hip, femoral neck and ulna bone mineral content. 12. dual energy x-ray absorptiometry is useful for monitoring bone response to exercise, because the method assesses bone geometry and small increments (due to loading physical activities) on the periosteal surface of the bone. 13. pedometers may be limited in their ability to reflect time spent in moderate-to-vigorous physical activity as they only measure steps per day and have a high amount of variability when used by people with different gait patterns. 14. in this study, moderate and combined moderate-to-vigorous activity was significantly associated with bone mineral content at the femoral neck whereas vigorous activity was associated with bone mineral content at the hip only. obesity in 7 10-year-old children in urban primary schools 15. south africa has the lowest rate of obesity in children in subsaharan africa. 16. the prevalence of childhood obesity in developing countries is associated more with children from lower socio-economic areas than their more economically privileged counterparts. dietary supplements containing prohibited substances 17. dietary supplement manufacturers have to prove the efficacy of their products before they are sold. 18. ephedrine is structurally similar to amphetamine and therefore has similar modes of action and a comparable side-effect profile. 19. the stimulant methylhexaneamine was originally intended to be marketed as a nasal decongestant, but has been detected as an ingredient of dietary supplements. chronic exertional compartment syndrome in the forearm 20. chronic exertional compartment syndrome of the forearm is common and is a well-known clinical condition. http://www.mpconsulting.co.za http://www.mpconsulting.co.za introduction pedometry is considered a valid and reliable objective measure of free-living physical activity (pa).1 however, a disadvantage of this methodology is that the primary measure which is usually reported, namely the number of steps, provides no information as to the intensity of the ambulation. consequently, it is not possible to disentangle the effects of volume and intensity of pa on outcome variables if statistical analyses only consider the number of steps (volume). we recently reported high ambulation levels (average steps. day-1) for a rural african population in transition but could not provide definitive data pertaining to the intensity at which steps were accumulated.2 the study used a piezo-electric based pedometer (nl-2000) which stored both the number of steps and activity energy expenditure (eeact). 2 the nl-2000 is produced by the suzuken-kenz company (http://www.suzuken-kenz.com) for a north american distributor (new lifestyles, http://www.new-lifestyles.com) and is identical in function to the suzuken-kenz e-step products (personal communication: hitoshi ozawa, suzuken-kenz, 17-052007). therefore calibration results for the nl-2000 would also be applicable to the suzuken-kenz e-step products.3-5 moreover, because the suzuken-kenz range includes the lifecorder ex, which has been validated,6,7 and the technology in this high-end product is essentially the same as the lower-end products (except for the download capacity to a personal computer), the algorithms for all suzuken-kenz products would be identical. for instance, the nl2000 (e-step) (personal communication: operations manager, new lifestyles, 02-09-2005) and the lifecorder ex 6 sense steps when there are three or more acceleration pulses for four consecutive seconds and calculate eeact using body mass (w) and an intensity dependent factor (ka) such that eeact (kcal) = ka x w (kg). effect of body mass and physical activity volume and intensity on pedometry-measured activity energy expenditure in rural black south africans in the limpopo province abstract objectives. we developed a novel approach to investigate patterns of pedometry-measured total weekly activity energy expenditure (eeact) in rural black south africans in the limpopo province. design. we analysed 7-day pedometry data in 775 subjects (female: n=508; male: n=267). variance components models for eeact were used to estimate the variance explained by body mass (bm), total weekly steps (volume) and estimated intensity (kcal. kg-1.step-1). univariate general linear models, adjusting for age, bm and physical activity (pa) volume, were used to determine if eeact was primarily affected by volume or intensity. results. bm (13.1%), pa intensity (24.4%) and pa volume (56.9%) explained 94.4% of the variance in eeact. adjusted eeact did not differ between sexes (78 kcal.week-1, p =0.2552). there were no significant differences across activity categories (sedentary to very active) for adjusted eeact (62 287 kcal.week -1, p>0.1). adjusted eeact for 6 7 days of compliance (≥10 000 steps.day-1) differed significantly from 1 2 days of compliance (266 419 kcal.week-1, p<0.04). obese (body mass index ≥30 kg.m-2) and normal weight (body mass index 18.5 24.9 kg.m-2) women did not differ significantly across activity categories for eeact (200 592 kcal.week -1, p>0.30). correspondence: ian cook physical activity epidemiology laboratory university of limpopo (turfloop campus) po box 459 fauna park 0787 polokwane south africa tel+fax: +27 15 268 2390 e-mail: ianc@ul.ac.za ian cook (ba (phys ed) hons, bsc (med) hons)1 marianne alberts (phd)2 estelle v lambert (phd)3 1 physical activity epidemiology laboratory, university of limpopo (turfloop campus), polokwane 2 department of chemical pathology, university of limpopo (turfloop campus), polokwane 3 mrc/uct research unit for exercise science and sports medicine, department of human biology, university of cape town sajsm vol 22 no. 1 2010 3 original research article conclusions. we have highlighted an intensity effect for days of compliance and at very active ambulatory levels (≥12 500 steps. day-1). a volume effect appeared to dominate between sexes, across activity categories and weight-by-activity categories. it is important that post hoc statistical adjustments be made for body mass and pa volume when comparing eeact across groups. consequently, the eeact displayed on the nl-2000 output is a function of the pa intensity (ka), pa volume (number of steps) and the individual’s body mass. it is thus not possible to ascertain if an eeact difference between two individuals is due to increased pa (volume and/or intensity) or because of body mass differences. one approach to circumvent this problem is to use statistical methods to adjust for body mass and pa volume to ascertain whether eeact differences between two individuals are possibly intensity dependent. therefore the objective of this study was to explore the patterns of pedometry-measured total weekly eeact by statistically adjusting for body mass and pa volume to determine if pa intensity could be an important factor in explaining the high ambulatory levels in a rural african setting. methods this analysis uses data for which the study protocol, subjects, field site, sample size and measurements have been described in detail elsewhere.2 briefly, 830 participants from the dikgale health and demographic surveillance system field site (dhdss) 8-11 were conveniently recruited and contacted twice over a 9-day period between january 2005 and december 2007. on the first occasion, subjects were recruited and completed the informed consent, relevant sections of a health questionnaire and provided anthropometric data. standard anthropometric measurements and interviews were performed by trained, local fieldworkers and included measures of stature (nearest 1 cm) and body mass (nearest 1 kg). we categorised subjects using body mass index (bmi = body mass ÷ stature2, underweight: <18.5 kg.m-2, normal weight: 18.5 24.9 kg.m-2, overweight: 25 29.9 kg.m-2, obese: ≥30 kg.m-2).12 finally, subjects were instructed on the required procedures for wearing the pedometer over 9 consecutive days. we used piezo-electric pedometers (nl2000, new lifestyles inc., kansas city, mo, usa) not affected by pedometer tilt or adiposity level13 to objectively measure pa. data for day 1 and day 9 were omitted because these were incomplete days. the pedometer was worn on the right waist, securely attached to a nylon belt and sealed with surgical tape. the pedometers could be removed for sleeping and bathing purposes by unclipping the nylon belt. ambulation pa volume was defined as the average steps. day-1 or steps.week-1. energy expenditure was defined as total activity energy expenditure.week-1 (eeact, kcal.week -1). we calculated a pa intensity factor (ifr, kcal.kg -1.step-1) from the total weekly steps, total weekly eeact and body mass. public health indices (thresholds) for steps.day-1 were defined as follows:14 sedentary: <5 000 steps. day-1, low active: 5 000 7 499 steps.day-1, somewhat active: 7 500 9 999 steps.day-1, active: 10 000 12 499 steps.day-1, and very active: ≥12 500 steps.day-1. a summary variable was created indicating the number of days a subject was compliant or not for 0 7 days (≥10 000 steps.day-1). subjects received a small honorarium on completion of the study. the study was approved by the ethics committee of the university of limpopo (turfloop campus). statistical analysis descriptive statistics comprised means and 95% confidence intervals (95% ci) or one standard deviation (sd). independent t-tests were used to compare variables across gender. variance components were estimated for inter-individual variance (body mass = kg, pa volume = total weekly steps and ifr = kcal.kg -1.step-1) and residual (intra-individual) variance. the variance components were also expressed as a percentage of the total variance. inter-individual variance represents true variation between subjects while intra individual variance represents unexplained variation within subjects. to identify additional variables that could affect the inter-individual variance we entered age and stature as covariates and sex, village and season as fixed factors. multiple linear regression models, using backward selection, were used to examine the relative importance of pa volume, pa intensity and body mass to eeact. in addition to pa and body mass variables, age and sex were included in all initial models. significance for variable entry into and exit out of the model were set at p=0.05 and p=0.1, respectively. univariate general linear models (glm) were used to compare ambulation (steps.day-1) and 4 sajsm vol 22 no. 1 2010 table i. descriptive characteristics for rural and urban women residence female (n=508) male (n=267) p† continuous variables age (years) 40.1 ± 20.7 28.4 ± 17.6 <0.0001 body-mass-index (kg.m-2) 26.6 ± 6.4 21.2 ± 3.9 <0.0001 average steps.day-1 11 086 ± 4 538 14 028 ± 5 434 <0.0001 average activity ee (kcal.day-1) 393 ± 189 491 ± 213 <0.0001 intensity factor (kcal.kg-1.step-1 x1000) 0.58 ± 0.28 0.65 ± 0.41 0.0032 categorical variables * body mass index classification normal weight (<25 kg.m-2) 47.8 (243) 87.6 (234) <0.0001 obese (≥30 kg.m-2) 27.2 (138) 4.1 (11) <0.0001 physical activity classification inactive (<5000 steps.day-1) 10.2 (52) 3.0 (8) 0.0006 active (≥10 000 steps.day-1) 59.4 (302) 77.9 (208) <0.0001 completion of secondary school (≥grade 12) 16.5 (58) 14.1 (29) 0.5420 ownership of motor vehicle (yes) 21.2 (99) 18.1 (45) 0.3911 electricity available inside house (yes) 75.4 (353) 65.3 (162) 0.0055 water collected outside dwelling (yes) 8.5 (40) 8.1 (20) 0.9363 data are reported as mean ± sd for all continuous variables and % (n) for * categorical variables, † p-values evaluate female v. male differences. eeact (kcal.week -1) across gender, activity categories (sedentary to very active), days of non-compliance/compliance with public health guidelines (≥10 000 steps.day-1), and obeseor normal-weight inactive (<7 500 steps.day-1), active (10 000 12 499 steps.day-1) and very active (≥12 500 steps.day-1) participants. all initial models adjusted for age and body mass. additional eeact models were also constructed which adjusted for age, body mass and steps.week-1. post hoc multiple comparison analyses (sidak’s t-test) assessed group differences. data were analysed using appropriate statistical software (spss version 17.0.2). significance for all inferential statistics was set at p<0.05. results we excluded 14 outliers identified during exploratory data analysis. because of very few obese males in the sample (table i), only adult (19 65 years) female subjects were used in the obese/normal weight comparison across activity categories. the sizeable variance attributed to body mass (13.1%), pa volume (total weekly steps, 56.9%) and ifr (kcal.kg -1.step-1, 24.4%) suggested further analysis was warranted to determine if eeact group differences persist, possibly due to an intensity effect, by adjusting for body mass and pa volume. the 5.5% error variance was likely due to the rather crude ifr that was calculated. entering age or stature as covariates, and sex, village or season as fixed factors, made no difference to variances (<1%). because the data were collected over 2 years in a number of villages that differ in terms of infrastructure and access to public transport, it was important to test whether season and village could explain part of the variance. pa volume, ifr and body mass were significant predictors of eeact (model and coefficients: p<0.0001, model adjusted r2=0.814) and part correlations were 0.887, 0.355 and 0.259, respectively. the multiple linear regression analysis revealed no collinearity between variables (variance inflation factors <1.2). the adjusted r2 for the partially (age and body mass) and fully (age, body mass and steps.wk-1) adjusted eeact glm models ranged from 0.130 to 0.564 and 0.690 to 0.695, respectively (p<0.0001). males accumulated significantly more steps than females (687 steps.day-1, p<0.0001). (fig. 1). the fully adjusted eeact was not significantly different (78 kcal.wk-1, p=0.2552) between sexes, suggesting no intensity effect (fig. 1). however, adjusting for age and body mass only resulted in a significant difference (224 kcal. week-1, p=0.0017), suggesting that volume plays a more significant role in eeact differences between sexes. age and body mass-adjusted differences in steps across categories (sedentary very active) were significant for all pairwise comparisons (1 783 steps.day-1 to 9 710 steps.day-1, p<0.0001) (fig. 2). adjusted for age and body mass, the middle three categories (low-active to active) resulted in relatively similar eeact, (p>0.1), but not so for two the extreme eeact categories (sedentary v. very active, p<0.04). however, the fully adjusted model yielded no significant differences across activity categories, suggesting a significant volume effect (p>0.1) (fig. 2). age and body mass-adjusted steps.day-1 for 6 7 days of compliance with public health guidelines (≥10 000 steps.day-1) were significantly different to all other levels of compliance (p<0.003) but there were no significant differences between 0 days (noncompliance) and 1 5 days of compliance (p>0.4) (fig. 1). adjusted for age and body mass, eeact differed significantly for days of compliance ≥6 compared with non-compliance (0 days) and lower levels of compliance (1 5 days) (p<0.03). significant differences persisted only for eeact for 6 7 days of compliance versus 1 2 days of compliance (p<0.04), suggesting an intensity effect only for 6 7 days of compliance (fig. 3). the eeact, adjusted for age and body mass of highly active normal weight and obese women was significantly higher than inactive normal weight and obese women (difference: 2 224 2 403 kcal.wk-1, p<0.0001). adjusted for age, body mass and steps. week-1, obese and normal weight adult females did not differ in eeact for the three pa categories, suggesting that there are no statistical differences in pa intensity (fig. 4). however, there was a tendency for normal weight females to have higher eeact (200 kcal.week -1 to 592 kcal.week-1, p>0.30). discussion this is a novel study reporting for the first time volume and intensity effects from data obtained using pedometers. the analysis has highlighted an intensity effect for days of compliance and especially at very active ambulatory levels (≥12 500 steps.day-1). interestingly, there did not seem to be a significant intensity effect between sexes, activity categories or obese versus normal weight across activity sajsm vol 22 no. 1 2010 5 2 female male 9000 9500 10000 10500 2800 2900 3000 3100 3200 steps.day-1 kcal.week-1 * mean ±95%ci a m b u la ti o n ( st ep s. d ay -1 ) e n erg y exp en d itu re (kcal.w eek -1) fig. 1. ambulatory and energy expenditure levels for males and females. steps.day-1 adjusted for age and body mass. kcal. week-1 adjusted for age, body mass and steps.week-1. * steps. day-1: males > females, p<0.0001. 3 4000 8000 12000 16000 2500 3000 3500 4000 steps.day-1 kcal.week-1 sedentary low active somewhat active active very active <5000 5000-7499 7500-9999 10 000-12 499 ≥12 500 means ±95%ci activity category (steps.day-1) a m b u la ti o n ( st ep s. d ay -1 ) e n erg y exp en d itu re (kcal.w e ek -1) fig. 2. ambulatory and energy expenditure levels across activity categories. steps.day-1 adjusted for age and body mass. kcal. week-1 adjusted for age, body mass and steps.week-1. steps. day-1: all activity categories significantly different, p<0.0001. categories once age, body mass and accumulated steps had been adjusted for. differences in accumulated steps between males and females have been reported.15,16 our results suggest that it is the difference in pa volume, and not pa intensity, that explains the difference in eeact between males and females from this rural, african setting. although average step totals increased significantly across activity categories, adjusted eeact did not increase accordingly. we also did not find markedly increased adjusted eeact between obese and normal weight females across activity categories, which is in agreement with findings of similar gross ee for walking and jogging at the same speed between normal weight and overweight/obese women, once adjusted for body mass and free fat mass.17 furthermore, non-compliance or compliance on 1 5 days of the week with public health guidelines (≥10 000 steps.day-1) 18 did not seem to reveal differences in eeact. however, complying on 6 7 days, required significant increases in volume and intensity. these results suggest that public health pa guidelines of at least 5 times per week, 30 minutes per session,19 which equates to approximately 10 000 steps.day-1,20-22 were likely met through increases in accumulated steps throughout the day instead of increasing pa intensity. it was interesting that these findings would seem to provide non-intervention, free-living support for the feasibility of promoting moderate intensity pa such that the lack of a vigorous intensity requirement would not be a barrier to increasing pa. in other words, our results suggest that within this rural african population, walking behaviours are naturally modelled according to public health pa guidelines. however, highly active groups such as those achieving ≥12 500 steps on 6 or more days a week, required increases in intensity. this finding is in accord with the significantly higher accelerometer-measured moderate-tovigorous pa recorded for subjects achieving ≥11 762 steps.day-1 compared with those achieving ≤8 123 steps.day-1; 68.6 min v. 23.6 min, respectively (p=0.000).22 le masurier et al. also reported higher moderate-to-vigorous activity for subjects achieving ≥10 000 steps. day-1 compared with <10 000 steps.day-1 whether accumulated in bouts ≥1-, ≥5or ≥10 min (difference: p<0.05).20 recently, dugas et al. suggested that pa intensity and not pa volume was a greater determinant of adiposity in young, black south african urban dwellers.23 our results would suggest that the pa volume is the dominant contributor to eeact in rural dwellers. moreover, we have shown that average steps.day-1 is significantly associated with adiposity levels in rural african women (r=-0.20, p=0.032).24 several limitations must be acknowledged. firstly, we could not compare our statistical adjustment against actual volume and intensity measures. future analyses using uni-axial accelerometer data to ascertain at which intensity levels steps are being accumulated would provide more definitive answers as to the relative importance of pa volume and intensity, specifically within the context of a rural african setting. secondly, the absolute eeact values reported in this study should be carefully interpreted because treadmill calibration studies for the nl-2000 suggest an overestimation of approximately 25% for eeact. 3 in conclusion, we have highlighted an intensity effect for 6 7 days of compliance and at very active ambulatory levels. a volume effect appeared to dominate between sexes, across activity categories and weight-by-activity categories and would suggest that public health messages in this specific rural setting should focus on maintaining pa volume through daily living rather than advocating increases in pa intensity. it is important that post hoc statistical adjustments be made for body mass and pa volume when comparing eeact data across groups. acknowledgements the research development and administration division of the university of limpopo (turfloop campus) and the thuthuka programme of the national research foundation supported this study. references 1. bassett dr, strath sj. use of pedometers to assess physical activity. in: welk gj ed. physical activity assessments for health-related research. champaign, il: human kinetics 2002:163-177. 2. cook i, alberts m, brits js, choma s, mkhonto ss. descriptive epidemiology of ambulatory activity in rural, black south africans. med sci sports exerc 2010; (in press). 3. crouter se, schneider pl, karabulut m, bassett dr. validity of 10 electronic pedometers for measuring steps, distance, and energy cost. med sci sports exerc 2003;35:1455-1460. 6 sajsm vol 22 no. 1 2010 5 obese normal obese normal obese normal 0 1000 2000 3000 4000 means ±95%ci inactive (<7500 steps.day-1) very active (≥12500 steps.day-1) active (10000-12499 steps.day-1) e n er g y ex p en d it u re ( kc al .w ee k1 ) fig. 4. ambulatory and energy expenditure levels for normal weight and obese women across activity categories. kcal. week-1 adjusted for age, body mass and steps.week-1. fig. 3. ambulatory and energy expenditure levels across number of days compliant (≥10 000 steps.day-1). steps.day-1 adjusted for age and body mass. kcal.week-1 adjusted for age, body mass and steps.week-1. * steps.day-1: 6 days and 7 days significantly different to all other days, p<0.003. † kcal.week-1: 1 2 days significantly different to 6 7 days, p<0.04. 4 0 1 2 3 4 5 6 7 7500 8750 10000 11250 12500 13750 15000 1000 1500 2000 2500 3000 3500 4000 steps.day-1 kcal.week-1 means ±95%ci * * number of days compliant (≥≥≥≥10 000 steps) a m b u la ti o n ( av er a g e s te p s. d ay -1 ) en e rg y ex p e n d itu re (kc al.w eek -1) † † sajsm vol 22 no. 1 2010 7 4. schneider pl, crouter se, lukajic o, bassett dr. accuracy and reliability of 10 pedometers for measuring steps over a 400-m walk. med sci sports exerc 2003;35:1779-1784. 5. schneider pl, crouter se, bassett dr. pedometer measures of freeliving physical activity: comparison of 13 models. med sci sports exerc 2004;36:331-335. 6. kumahara h, schutz y, ayabe m, et al.the use of uniaxial accelero metry for the assessment of physical-activity-related energy expenditure: a validation study against whole-body indirect calorimetry. br j nutr 2004;91:235-243. 7. mcclain jj, craig cl, sisson sb, tudor-locke c. comparison of life corder ex and actigraph accelerometers under free-living conditions. appl physiol nutr metab 2007;32:753-761. 8. alberts m, burger s. indepth dss site profiles: dikgale dss, south africa. in: sankoh oa, kahn k, mwageni e, ngom p, nyarko p, eds. population and health in developing countries.volume 1. population, health, and survival at indepth sites. ottawa: idrc, 2002: 207-211. 9. alberts m, urdal p, steyn k, et al. prevalence of cardiovascular diseases and associated risk factors in a rural black population of south africa. eur j cardiovasc prev rehabil 2005;12:347-354. 10. cook i, alberts m, burger s, byass p. all-cause mortality trends in dikgale, rural south africa, 1996-2003. scand j public health 2008;36:753-760. 11. alberts m, burger s, tollman sm. the dikgale field site. s afr med j 1999;89:851-852. 12. puoane t, steyn k, bradshaw d, et al. obesity in south africa: the south african demographic and health survey. obes res 2002;10:1038-1048. 13. crouter se, schneider pl, bassett dr. spring-levered versus piezoelectric pedometer accuracy in overweight and obese adults. med sci sports exerc 2005;37:1673-1679. 14. tudor-locke c, bassett dr. how many steps/day are enough? preliminary pedometer indices for public health. sports med 2004;34:1-8. 15. mccormack g, giles-corti b, milligan r. demographic and individual correlates of achieving 10,000 steps/day: use of pedometers in a populationbased study. health promot j austr 2006;17:43-47. 16. tudor-locke c, johnson wd, katzmarzyk pt. accelerometer-determined steps per day in us adults. med sci sports exerc 2009;41:1384-1391. 17. le cheminant jd, heden t, smith j, covington nk. comparison of energy expenditure, economy, and pedometer counts between normal weight and overweight or obese women during a walking and jogging activity. eur j appl physiol 2009;106:675-682. 18. tudor-locke c, hatano y, pangrazi rp, kang m. revisiting “how many steps are enough?”. med sci sports exerc 2008;40:s537-s543. 19. haskell wl, lee im, pate rr, et al. physical activity and public health: updated recommendation for adults from the american college of sports medicine and the american heart association. med sci sports exerc 2007;39:1423-1434. 20. le masurier gc, sidman cl, corbin cb. accumulating 10,000 steps: does this meet current physical activity guidelines? res q exerc sport 2003;74:389-394. 21. hultquist cn, albright c, thompson dl. comparison of walking recommendations in previously inactive women. med sci sports exerc 2005;37: 676-683. 22. macfarlane dj, chan d, chan kl, ho ey, lee cc. using three objective criteria to examine pedometer guidelines for free-living individuals. eur j appl physiol 2008;104:435-444. 23. dugas lr, carstens ma, ebersole k, et al. energy expenditure in young adult urban informal settlement dwellers in south africa. eur j clin nutr 2009;63:805-807. sajsm 376.indd sajsm vol. 25 no. 3 2013 67 objective. to evaluate whether three-dimensional (3d) musculoskeletal modelling could be effective in assessing the safety and efficacy of exercising on a seated row resistance-training machine. the focus of the evaluation was on biomechanical and anthropometric considerations of the end user. methods. three anthropometric cases were created; these represented a 5th percentile female as well as a 50th and a 95th percentile male based on body mass index. two repetitions, with a resistance equal to 50% of the functional strength of one repetition maximum (1rm) for each anthropometric case, were performed. results. results indicate that the default model of the lifemodeler software has important limitations that should be taken into consideration when used to evaluate exercise equipment. adjustments had to be made to the model to solve the forward dynamics simulations; as a result, no muscle forces or contraction values were obtained. this negatively influenced the value of the results as these parameters are important when analysing an exercise. the seated row resistance-training machine’s engineered or manufactured adjustability was sufficient, as it appeared to accommodate the three anthropometric cases adequately during execution of this exercise. conclusion. it appears that 3d musculoskeletal modelling can be used to evaluate resistance-training exercises such as the seated row; however, the limitations indicated by this study must be taken into consideration, especially when using the default lifemodeler model. s afr j sm 2013;25(3):67-73. doi:10.7196/sajsm.470 three-dimensional musculoskeletal modelling of the seated row resistance-training exercise k nolte,1 phd; p e krüger,1 phd; p s els,2 phd; h w nolte,3 phd 1 department of biokinetics, sport and leisure sciences, university of pretoria, pretoria, south africa 2 department of mechanical and aeronautical engineering, university of pretoria, pretoria, south africa 3 ergonomics technologies, research and development, armscor, south africa corresponding author: k nolte (kim.nolte@up.ac.za) the advancement in computer technology and data processing capability has allowed the improvement of modelling software to a point where dynamic problems can now be simulated and analysed in a digital environment.[1] with the capability to simulate musculoskeletal human models interacting with mechanical systems, many aspects concerning the effects of the resistance-training equipment on the body can be studied. in recent years, the popularity of dynamic resistance training has risen. this type of training is suitable for developing muscular fitness 68 sajsm vol. 25 no. 3 2013 of men and women of all ages, as well as of children.[2] the seated row forms the basis of many land-based training programmes for athletes, more specifically rowers. however, it is also often included as part of strength-training programmes for non-athletes. it is an effective exercise to strengthen the musculature of the upper back. the primary joint movements of this exercise are shoulder extension and elbow flexion, thus the prime movers include the latissimus dorsi and the biceps brachii muscles.[2] other important muscles involved in the seated row exercise are the posterior deltoids, trapezius and rhomboideus muscle groups.[3] in terms of understanding the biomechanics associated with various resistance-training exercises, a great deal of literature has investigated the kinetics and kinematics associated with the bench press, squat and olympic lifts. therefore, it would appear that there has been a preoccupation with extension-type tasks and very little attention has been given to other movements.[4] furthermore, much of the available research focuses on rowing ergometer analysis rather than the seated row resistance exercise. here we present the musculoskeletal modelling of three anthropometric cases upon exercising on a commercially available seated row resistance-training machine. the primary aim of this study was to determine the efficacy of three-dimensional (3d) musculoskeletal modelling in evaluating resistance-training equip ment design such as the seated row resistance-training machine. methods equipment a 3d full-body musculoskeletal model was created using lifemodeler software and incorporated into a multibody dynamics model of the seated row resistance machine generated in msc adams software (fig. 1). lifemodeler runs as a plug-in of msc adams. it has previously been used in studies in the fields of sport, exercise and medicine.[5,6] it was decided to evaluate a default model as generated by the software. this model consists of 19 segments including a base set of joints for each body region. specifically, the spine does not consist of individual vertebrae, but rather of various segments that represent different regions of the vertebral column, with joints between these segments. furthermore, the default model has a fullbody set of 118 muscle elements attached to the bones at anatomical landmarks, including most of the major muscle groups in the body. closed-loop simple muscles were modelled. closed-loop muscles contain proportional-integral-differential (pid) controllers. the pid controller algorithm uses a target length v. time curve to generate the muscle activation and the muscles follow this curve. because of this approach, an inverse dynamics simulation using passive recording muscles is required prior to simulation with closed-loop muscles. simple muscles fire with no constraints, except for the physiological cross-sectional area (pcsa), which designates the maximum force that a muscle can exert. the graphs of simple muscle activation curves will generally peak at a flat-force ceiling value.[7] musculoskeletal full-body human and seated row computer-aided design (cad) models three anthropometric cases were created for each piece of equipment. the human models were created using the gebod anthropometry database (default lifemodeler database), but were based on body mass index (bmi) data obtained from rsa-mil-std 127 vol. 1[8] – a representative anthropometry standard of the south african national defence force (sandf) that is kept current by a yearly sampling plan, and is an accurate representation of the broader south african (sa) population. bredenkamp[9] described a process to characterise the body forms of sandf males and females. body form variances described by two principle components (pcs) for the sandf males and two pcs for sandf females were included in the modelling process. positive and negative boundary cases of each pc, representing the boundary conditions to be accommodated in design, identified the total range of four male and four female models.[10] the first pc described the ‘fatness’ variance in the population. anthropometric variables included for this pc are bust, waist and hip circumferences, together with bmi and bust-to-waist ratio. the second pc described the length variances in the population. anthropometric variables included for this pc are stature, inside-arm length and crotch length. it was decided to use the cases representing the smallest female as well as an average and large male for the three anthropometric cases for this study. these cases could be seen as what are traditionally known as a 5th percentile female, 50th percentile male and a 95th percentile male based on the bmi of each of these cases. thus, for the purpose of building these biomechanical models, a correlation between bmi and functional body strength was assumed. similar assumptions have previously been made in biomechanics full-body model simulations.[11] annegarn et al.[12] also verified scaled modelling strengths against actual functional body strengths and correlations ranged from 0.64 to 0.99. this approach was followed to ensure that the equipment could accommodate an acceptable sample of the sa end-user population. a cad model of the seated row resistance-training machine was obtained from an exercise equipment manufacturing company in sa. the model in a parasolid file format was imported into the lifemodeler simulation software. the msc adams software was used to create two design variables in order to adjust the external resistance (as selected by the amount of weights when using a selectorised resistance-training machine) and to specify the radius of the cam over which the cable of an actual exercise machine would run in order to lift the selected resistance. this was possible since this machine employed a circular cam system. a special contact force (solid to solid) was created between the weights being lifted and the remainder of the weight stack during the simulation. a coupler joint was created, linking the revolute joint (driver) of the lever arm attached to the handle bars with the translational joint of the weight stack. the design variable created for the radius of the cam was referenced as the scale of the coupled joint (translational joint at weights). the design variable created for the mass of the weights was then adjusted according to the pre-determined resistance for each anthropometric case. the external resistance applied in the models was based on data obtained from rsa-mil-std 127 vol. 5.[13] this database consists of a range of human functional-strength measurement variables for sandf males and females. this standard can be considered an accurate representation of the functional body strength of the sa population.[13] furthermore, functional strength data were used from activities that most closely resembled the movements of the exercise as well as the muscle groups used during such movement. fifty per cent of the functional strength of one repetition maximum (1rm) for each anthropometric case was used as this can be considered a sajsm vol. 25 no. 3 2013 69 manageable resistance to perform an exercise with appropriate form and technique for two repetitions. the end of the concentric phase of each repetition was when the upper arms reached the anatomical zero position (neutral) alongside the torso, after which the eccentric phase of each repetition returned the model to the starting position described in table 1. simulation extreme care was taken with the positioning of the musculoskeletal model on the seated row machine to ensure that technique, posture and positioning were correct according to best exercise principles (table 1). optimal positioning of the models on the equipment required approximately 90º of shoulder flexion with slight elbow flexion that resulted in the hands finally being just higher than the elbows for all anthropometric cases. this would be considered the correct posture for this exercise and resulted in the handle height being just below shoulder level for all cases. furthermore, total manufacturer adjustability of the exercise machine was used in order to ensure correct positioning for each case. the following steps were performed to ensure realistic kinematics during the inverse dynamics simulations: (i) positioning of the human model on the exercise equipment; (ii) adjustment of the posture to allow for the human-machine interface to be created; (iii) creating the constraints between the human and machine; (iv) prescribing the motion of the repetitions; (v) evaluation of the resultant kinematics; and (vi) adjustment of joint positions until inverse dynamics resulted in a realistic exercise movement. bushing elements were used to secure the chest to the chest pad/cushion as well as the lower torso to the seat, and spherical joints were used to connect the hands to the handlebars of the seated row machine. bushing elements were preferred to fixedjoint elements; the former allows limited translational and rotational motion, and the amount of motion can be controlled by changing stiffness and damping characteristics in all three orthogonal directions. the original joints created in the biomechanical model had default joint parameters (stiffness (k) =1e4, dampening (c) =1 000). joints with such high joint stiffness are created to ensure a relatively ‘rigid’ model that provides a stable and smooth motion when manipulated by motion splines. this is especially important during the movement of the model into the initial posture, and to ensure smooth model motion during inverse dynamics. after the muscle lengths had been recorded in the inverse dynamics, the joint stiffness was changed to near zero, to represent actual stiffness in normal and healthy human joints. the inverse dynamics/forward dynamics method was applied during the simulations. inverse dynamics simulations are performed on models that are being manipulated by the use of motion agents or motion spines. during the inverse dynamics simulation, a rotational motion was applied to the revolute joint of the lever arm attached to the handlebars of the seated row machine in order to generate the required movement of the resistance-training machine. this movement replicated the pulling (concentric) and resisting (eccentric) phase of the exercise. the time for fig. 1. 3d musculoskeletal modelling of the seated row resistance-training machine and 50th percentile male musculoskeletal model using lifemodeler and msc adams software. table 1. exercise starting posture for the three anthropometric cases on the seated row machine* joint 5th percentile female 50th percentile male 95th percentile male scapula† 0.0; 0.0; 0.0 0.0; 0.0; 0.0 0.0; 0.0; 0.0 shoulder† 85.0 (f); 5.0 (ir); 7.0 (ab) 85.0 (f); 5.0 (ir); 4.5 (ab) 85.0 (f); 5.0 (ir); 2.5 (ab) elbow† 15.0 (f); 10.0 (ir); 0.0 15.0 (f); 10.0 (ir); 0.0 15.0 (f); 10.0 (ir); 0.0 wrist† 0.0; 0.0; 0.0 0.0; 0.0; 0.0 0.0; 0.0; 0.0 hip† 30.0 (f); 0.0; 0.0 35.0 (f); 0.0; 0.0 52.0 (f); 0.0; 0.0 knee† 30.0 (f); 0.0; 0.0 45.0 (f); 0.0; 0.0 60.0 (f); 0.0; 0.0 ankle† 0.0; 0.0; 0.0 12.0 (e); 0.0; 0.0 12.0 (e); 0.0; 0.0 upper neck 0.0; 0.0; .0.0 0.0; 0.0; 0.0 0.0; 0.0; 0.0 lower neck 0.0; 0.0; .0.0 0.0; 0.0; 0.0 0.0; 0.0; 0.0 thoracic 0.0; 0.0; .0.0 0.0; 0.0; 0.0 0.0; 0.0; 0.0 lumbar 15.0 (f); 0.0; 0.0 15.0 (f); 0.0; 0.0 15.0 (f); 0.0; 0.0 f = flexion; e = extension; ir = internal rotation; ab = abduction. * results are presented for the sagittal, transverse and frontal planes (degrees). † the joint angles refer to bilateral joints. 70 sajsm vol. 25 no. 3 2013 the concentric phase was set at 1.66 s and the eccentric phase longer at 3.33 s to mimic conventional resistance-training technique in which the eccentric phase is more deliberate to prohibit the use of momentum. the 1.66 s concentric phase included a step function approximation over 0.5 s to ensure a gradual start to the movement. in msc adams, the step function approximates an ideal mathematical step function. it steps quantities such as motions or forces up or down, or on and off. a step function is used when a value needs to be changed from one constant to another. the joints forces of the model were recorded during the inverse dynamics simulation in order to calculate the changes in joint torques to result in the required machine movement. after the inverse dynamics simulation was performed, the rotation al motion was removed from the rotational joint of the lever arm of the seated row machine. the resulting joint movements were then used to drive the model during the forward dynamics simulation in the manner as developed through the inverse dynamics simulation. during the forward dynamics simulation, the model is guided by the internal forces (muscle-length changes resulting in joint angulations and torques) and influenced by external forces (gravity, contact and determined exercise resistance). it is important to note that changes had to be made to the lifemodeler default model in order to solve the models with plausible kinematics during the forward dynamics simulations. considering the research problem, the detail of these changes will be discussed under the discussion section. all results presented are derived from the forward dynamics simulations after these changes to the default model were made. data analysis firstly, we determined if the forward dynamics simulations could adequately be solved by the lifemodeler default model. kinematic data obtained from the inverse dynamics simulations were visually compared with those of the forward dynamics simulations to determine if the data were plausible. secondly, the anthropometric dimensions and exercise postures of the musculoskeletal human models were visually assessed in relation to the dimensions and adjustability of the resistance-training equipment in order to determine if all three anthropometric cases representative of the sa end-user population could be accommodated comfortably on the seated row resistance-training machine. key aspects included start and end exercise posture, as well as maintaining correct technique throughout the exercise during the simulations. correct technique was assessed in terms of limited compensatory movements and performing the seated row exercise through the full range of motion as determined by the inverse dynamics. lastly, to determine exercise safety and efficacy, joint forces were evaluated. the risk of injury to the musculoskeletal system of the exerciser was ascertained by comparison of measured forces with safe loading limits for joints of the lumbar and thoracic spine. risk to both these structures are real during exercises that require pulling or pushing movements (with and without resistance) and/or during the execution of exercises with poor postures. different joint-loading criteria were derived using biomechanical research, taking into consideration the posture and anthropometry.[14] however, criteria for determining whether a particular task or exercise is ‘safe’ based on tissue-level stresses or joint loading are available only for a small number of tissues and loading regimes (e.g. lower-back motion segments in compression);[1] therefore, for this study, anterior/posterior (a/p) shear forces and joint compression forces were used as safety criteria. basic descriptive statistical analyses were completed with satistica. results three anthropometric cases based on bmi data obtained from rsamil-std 127 vol. 1[13] were used for the study, and results were assessed (table 2). table 2 represents the external resistance applied for each anthropometric case. due to the involvement of the wrist, elbow and shoulder joints in the seated row exercise, torque values for these joints are presented in table 3. the 95th percentile male recorded the highest peak joint torque values for the three joints. the 50th percentile male’s peak elbow and wrist torque values were the lowest. the peak shoulder torque values of the 5th percentile female and 50th percentile male were similar and were lower than the 95th percentile male’s values. for the three anthropometric cases, the peak shoulder joint torque values were the lowest, followed by the wrist and the greatest for the elbow. the seated row exercise is a multi-joint exercise, thus movement in the sagittal plane of the shoulder, elbow and wrist (right side) are reported (table 3). the least movement occurred at the wrist joint, followed by the shoulder joint, with the most movement at the elbow joint for the three anthropometric cases. range of motion of the 5th percentile female was the least for the wrist and shoulder joints. range of motion was the greatest for the 95th percentile male in the wrist and shoulder joint. elbow joint range of motion was greatest for the 50th percentile male. results for the thoracic (t12/l1 intervertebral joint) and lumbar (l5/s1 intervertebral joint) spine compression and a/p shear forces are presented in table 4. peak thoracic spine joint compression forces were greatest for the 50th percentile male, followed by the 95th percentile male, and were lowest in the 5th percentile female. there was a similar trend in the peak lumbar spine joint compression forces. in all anthropometric cases, the peak lumbar spine joint compression forces were greater than the peak thoracic spine joint compression forces. the 5th percentile female and 50th percentile male recorded similar peak thoracic and lumbar spine a/p shear forces. the 5th percentile female’s peak thoracic spine and lumbar a/p shear forces were the least in comparison with the other two anthropo metric cases. table 2. user population anthropometric and strength data user population group body mass (kg) stature (mm) exercise resistance 50% of 1rm (kg) 5th percentile female 49.5 1 500 11 50th percentile female 66.0 1 610 18 95th percentile male 85.0 1 840 30 sajsm vol. 25 no. 3 2013 71 the results for wrist and elbow-joint a/p shear forces are presented in table 4. peak wrist and elbow-joint a/p shear forces were lowest for the 50th percentile male and highest for the 95th percentile male. peak wrist a/p shear forces were slightly lower than elbow shear forces for all the anthropometric cases. discussion firstly, it can be concluded that the lifemodeler default model was not adequate to solve the forward dynamics simulations for any of the anthropometric cases. the same conclusion[15] was drawn in a previous study that evaluated the seated biceps curl resistancetraining exercise. for the evaluation of the seated biceps curl exercise, the forward dynamics simulations could also only be solved after a number of adjustments had been made to the model, such as increasing the pcsa of the muscles, manipulating muscle origins and insertions, and decreasing the joint stiffness in the forwards dynamics simulations. [15] all of these adjustments were implemented for this study in order to solve the simulation, without any success. possible reasons for this include the degrees of freedom involved in a multijoint exercise involving highly mobile joints such as the shoulder. furthermore, it could be that additional musculature is required to provide more stability in the shoulder joint during the forward dynamics simulations. to solve this problem in this study, the joint angulations recordings in the inverse dynamics simulations were used to solve the forward dynamics simulations. while this approach should still result in plausible compression and a/p shear reaction forces, the muscle-length changes resulting in such compression forces are not available for evaluation. rather, this option creates a trained pid-servo-type controller on the joint axis. the joint is commanded to track an angular history spline with a user-specified gain on the error between the actual angle and the commanded error. a user-specified derivative gain is specified to control the derivative of the error. therefore, results for muscle forces (n) and contractions table 3. right wrist, elbow and shoulder joint torque (nm) and joint angle (°) results in the sagittal plane for the three anthropometric cases* mean minimum maximum 5th percentile female wrist torque (nm) wrist angle (°) -1.6 16.0 -4.5 0.0 0.0 26.5 elbow torque (nm) elbow angle (°) -4.0 -75.8 -6.3 -129.6 0.0 -15 shoulder torque (nm) shoulder angle (°) 0.9 -52.0 -1.2 -85.0 3.2 -16.4 50th percentile male wrist torque (nm) wrist angle (°) -1.3 16.3 -3.1 0.0 0.0 27.5 elbow torque (nm) elbow angle (°) -3.0 -75.9 -4.7 -130.5 0.0 15.0 shoulder torque (nm) shoulder angle (°) 0.2 -53.7 -1.2 -85 1.9 -20.8 95th percentile male wrist torque (nm) wrist angle (°) -0.2 17.1 -4.8 0.0 2.3 29.0 elbow torque (nm) elbow angle (°) -13.3 -73.2 -19.5 -125.9 0.0 -15.0 shoulder torque (nm) shoulder angle (°) 1.7 -57.8 -2.5 -85.0 7.0 -28.6 * joint torque values: negative indicates torque during the concentric phase of the exercise and positive indicates torque during the eccentric phase of the exercise. joint angle values should be interpreted together with table 1. table 4. joint compression and a/p shear forces (n) for the three anthropometric cases n mean minimum maximum 5th percentile female compression forces* thoracic spine lumbar spine 100.3 145.0 79.4 124.1 149.1 193.8 a/p shear forces† thoracic spine lumbar spine wrist elbow -22.0 -22.0 42.0 41.9 -30.8 -30.8 16.3 10.3 -18.3 -18.3 55.7 56.6 50th percentile male compression forces* thoracic spine lumbar spine 140.0 200.0 113.7 -173.2 168.1 227.6 a/p shear forces† thoracic spine lumbar spine wrist elbow -31.4 -31.4 29.7 29.7 -36.6 -36.6 16.6 10.2 -18.3 -18.3 42.8 43.8 95th percentile male compression forces* thoracic spine lumbar spine -32.7 28.2 -97.1 -36.1 162.8 223.9 a/p shear forces† thoracic spine lumbar spine wrist elbow 0.4 0.4 103.6 103.5 -36.2 -36.2 31.7 18.7 -12.4 -12.4 122.4 124.1 a/p = anterior/posterior. * positive values indicate forces in a superior direction and negative values indicate forces in an inferior direction. † positive indicates forces in a posterior direction and negative indicate forces in an anterior direction. 72 sajsm vol. 25 no. 3 2013 (shortening and lengthening) (mm) could not be analysed. ideally these parameters should be analysed when evaluating an exercise. it appears that more complex, multi-joint or compound exercises that require too many degrees of freedom pose a problem for the default model; therefore, models with more detailed musculature may be required to solve the forward dynamics simulations sufficiently. important musculature required for the performance of the seated row exercise that are not included in the lifemodeler default model are the rhomboideus major and minor and the rotator cuff group (supraspinatus, infraspinatus, teres minor and subscapularis). it was not, however, within the scope of this study to produce anatomical detailed models, but rather to evaluate the default model of the software. secondly, the study did not indicate any obvious discrepancies between the anthropometric dimensions of the three cases and the seated row machine’s engineered or manufactured adjustability. all three anthropometric cases appeared to be positioned adequately on the seated row machine. this was not the case with previous studies conducted on the abdominal crunch and seated biceps curl machines, which demonstrated the inability of the machines to adjust appropriately to individuals with small anthropometric dimensions, such as some women and children.[15,16] as a result the exercise technique of the 5th percentile female was negatively influenced and injury risk was increased for these two exercises.[15,16] lastly, with regards to the biomechanical evaluation in terms of exercise efficacy and injury risk, the following could be deduced from the study: due to the fact that the forward dynamics simulations was solved by recording the joint angulations changes during the inverse dynamics simulations and not muscle-length changes, results for the muscle forces and contractions were not obtained and could therefore not be analysed. this negatively influenced the value of modelling with regards to evaluating the seated row exercise, as muscle forces and contractions provide important information regarding the efficacy and injury risk of the exercise. maximal joint torque values obtained for the wrist, elbow and shoulder appear to be lower when comparing the values to peak values obtained by means of isokinetic testing at 60º/s, e.g.: wrist flexion and extension values of 13.8 nm and 12.7 nm, respectively, in nondisabled subjects;[17] elbow flexion and extension values of 36 nm for both elbow flexion and extension in female college basketball players; and shoulder flexion and extension values of 77 nm and 53 nm for males and 38 nm and 24 nm for females, respectively, in a group of non-disabled.[18,19] joint torque values for the three joints evaluated were much lower than values obtained during peak isokinetic testing; however, it is important to bear in mind that the values obtained in this study were not obtained from maximal testing as with the isokinetic testing. the peak elbow joint torque was the highest recorded value for all joints in the three anthropometric cases, which was too be expected as the elbow joint is most involved in the seated row movement. not surprisingly, the joint range of motion (wrist, elbow and shoulder) used during the seated row exercise was smallest for the 5th percentile female and greatest for the 95th percentile male; with the exception of the elbow joint range of motion, which was greatest for the 50th percentile male. it is not only important that correct technique is used for resistance exercises such as the seated row in order to decrease the likelihood of injury, but also that exercises are performed through the full range of motion to get the maximum benefits of the exercise. in addition to lifting, pushing and pulling may also be associated with significant risk to the low back.[20] the seated row exercise can be considered a pulling activity. it must be kept in mind that the cited research is primarily referring to occupational tasks; however, important similarities and conclusions can be drawn with exercises that use similar actions to occupational tasks and activities that require pulling. furthermore, the spine of the default model does not consist of all the individual vertebrae, but rather of various segments that represent the different regions of the vertebral column with joints between these segments. individualised vertebrae and corresponding joints may produce different results. in 2009, a study by knapik and marras[21] found that there was greater compressive loading at all spine levels when performing pulling compared with pushing activities. therefore, an individual performing a pulling exercise such as the seated row may be at greater risk of a back injury than individuals performing a pushing exercise such as bench press, specifically with regards to compressive loading. [21] previous research from the american national institute for occupational safety and health (niosh)[20] recommended that spinal compression forces should not exceed 3.4 kn, to avoid injury. however, there is a very real threat of musculoskeletal injury before this failure limit value has been reached.[14,21] british standards (bs en 1005-3, 2002) recommend 600 n as the cut-off point for carrying masses; no further recommendations are made, except ‘time of exposure needs to be minimised’ and ‘a preferred system requires optimal ergonomic position with reduced back bending posture’.[22] therefore, all three anthropometric cases were well below the recommended failure limit of 3.4 kn. none of the anthropometric cases’ peak thoracic or lumbar compression forces were even near the recommended 600 n cut-off; therefore, it may be postulated, all things considered, that the seated row exercise does not appear to cause excessive spinal compression forces that may put the individual at risk for an injury. historically, spine compression in the lower lumbar spine has been the variable of interest for risk to the low back during work and exercise training. however, during horizontal force application (pulling of the seated row exercise), it is expected that shear forces within the spine increase dramatically due to the application of force in the hands and the reaction of the trunk musculature. thus, shear forces may represent the critical measure of risk.[21] according to knapik and marras,[21] in general, pushing activities impose greater, potentially risky a/p shear forces upon the spine than pulling. pushing imposed up to 23% greater a/p shear forces compared with pulling. increases in shear forces were as a result of the increased flexor muscle co-activity required for the activity.[21] although the spine a/p shear forces recorded were greater than the compression forces, the thoracic and lumbar spine joint a/p shear forces for the three anthropometric cases were also below the most commonly cited spine tolerance of 1 000 n for shear force, as stipulated by mcgill. [23] it is important to note that even if the spine compression and a/p shear forces recorded were well within acceptable limits, the modelling does not take into account the repetitive nature and accumulative effect of exercise. further, the resistance used was only 50% of each case’s estimated 1rm; therefore, if exercises use a resistance closer to their maximum, the loading values may exceed the acceptable limits. sajsm vol. 25 no. 3 2013 73 handle height appears to affect the mechanical load of the low back and shoulder considerably, and it is recommended that carts are designed and are adjustable so that it is possible to push or pull at shoulder height.[24] the same principle can be applied to the seated row machine: the handle bars should be approximately at shoulder height, which was the case for the three anthropometric models. thus, this could have assisted in reducing the spine loads, especially the a/p shear spine forces. unfortunately, after conducting a literature search, it became clear that information regarding a/p shear forces of the shoulder, elbow and wrist joints is scarce. however, the following information regarding handle height may be applicable in terms of reducing a/p shear forces on these joints during the seated row exercise. handle height and the magnitude of force are found to be significantly related to the net moment at the shoulder. net moments at the shoulder are kept low during pushing and pulling activities by keeping the wrist, elbow and shoulder close to the line of action of the exerted force, or by directing the exerted force such that the shoulder joint remains close to the line of action of the exerted force.[24] thus, if the handle bars of the seated row resistance-training machine are designed in such a way as to ensure correct alignment of the shoulder, elbow and wrist joints, it may assist in reducing the strain that these joints experience during this exercise, especially if a heavy resistance is used. conclusion three-dimensional musculoskeletal modelling has value in the evaluation of the safety and efficacy of resistance-training equipment. this modelling method is a valuable tool for equipment design and may be of use to assess injury risk. however, musculoskeletal modelling that makes use of default models that lack adequate biofidelity does have limitations, as highlighted here. adjustments had to be made to the default model to solve the forward dynamics simulations using recorded joint angulations during the inverse dynamics simulations. as a result, no muscle (force and contraction) results could be obtained which negatively affected the value of the modelling effort in evaluating the seated row exercise in terms of efficacy and safety. from an equipment design perspective, the anthropometric dimensions of the end-users appeared to be accommodated adequately by the seated row’s engineered or manufactured adjustability. practically, this study highlights the possible risk for spinal injury associated with pulling activities. our results emphasise the importance of exercising with correct positioning and technique at an appropriate external resistance, to avoid undue strain on spinal structures. references 1. wagner d, rasmussen j, reed m. assessing the importance of motion dynamics for ergonomic analysis of manual materials handling tasks using the anybody modelling system. proceedings of the 2007 digital human modelling for design and engineering conference, seattle, washington, 2007. 2. heyward vh. advanced fitness assessment and exercise prescription. 5th ed. champaign, usa: human kinetics, 2004. 3. floyd rt. manual of structural kinesiology. 17th ed. new york: mcgraw-hill, 2009. 4. cronin jb, jones jv, hagstrom jt. kinematics and kinetics of the seated row and implications for conditioning. j strength cond res 2007;21(4):1265-1270. [http:// dx.doi.org/10.1519/r-21246.1] 5. de jongh c. critical evaluation of predictive modelling of a cervical disc design. unpublished dissertation. stellenbosch: university of stellenbosch, 2007. 6. hofmann m, danhard m, betzler n, et al. modelling with brg.lifemodtm in sport science. int j comp sci sport 2006;5:68-71. 7. biomechanics research group, inc. lifemod biomechanics modeler manual. san clemente, usa: life modeler, 2006. 8. rsa-mil-std-127. ergonomic design: anthropometry and environment. pretoria: rmss, 2004:1-196. 9. bredenkamp k. the characterisation of the male and female body forms of the sandf. pretoria: ergotech, 2007. 10. gordon cc, brantley jd. statistical modelling of population variation in the head and face. proceedings of the 1997 design and integration of helmet systems international symposium, massachusetts, usa, 1997. 11. rasmussen j, de zee m, damsgaard a, et al. a general method for scaling musculoskeletal models. paper presented at the international symposium on computer simulation in biomechanics, cleveland, ohio, usa, 2005. 12. annegarn j, rasmussen j, savelberg hhcm, et al. strength scaling in human musculoskeletal models. paper presented at the european workshop on movement sciences, amsterdam, the netherlands, 2007. 13. rsa-mil-std-127. ergonomic design: biomechanics – specific functional body strength data standard. pretoria: rmss, 2001:1-28. 14. cooper g, ghassemieh e. risk assessment of patient handling with ambulance stretcher systems (ramp/winch), easy-loader, tail-lift using biomechanical failure criteria. med eng phys 2007;29:775-787. [http://dx.doi.org/10.1016/j.medengphy.2006.08.008] 15. nolte k, krüger pe, els ps. three dimensional musculoskeletal modelling of the seated biceps curl resistance training exercise. sport biomech 2011;10:146-160. [http://dx.doi.org/10.1080/14763141.2011.577441] 16. nolte k, krüger pe, els ps, nolte h. three dimensional musculoskeletal modelling of the abdominal crunch resistance training exercise. j sports sci 2013;31:265-275. [http://dx.doi.org/10.1080/14763141.2011.577441] 17. van swearingen jm. measuring wrist muscle strength. j orthop sports phys ther 1983;4:217-228. 18. berg k, blank d, muller m. muscular fitness profile of female college basketball players. j orthop sports phys ther 1985;7:59-64. 19. nicholas jj, robinson lr, logan a, et al. isokinetic testing in young non-athletic able-bodied subjects. arch phys med rehabil 1989;70:210-213. 20. national institute for occupational safety and health. musculoskeletal disorders and workplace factors: a critical review of epidemiologic evidence for workrelated musculoskeletal disorders of the neck, upper extremity, and low back. us department of health and human services (dhhs) public health service, centres for disease control. cincinnati: national institute for occupational safety and health division of biomedical of behavioural science, 1997. 21. knapik gg, marras ws. spine loading at different lumbar levels during pu s h i ng an d pu l l i ng . e rgon om i c s 2 0 0 9 ; 5 2 ( 1 ) : 6 0 7 0 . [ http : / / d x . d oi. org/10.1080/00140130802480828] 22. british standards institute. bs en 1005 – 3. safety of machinery – human physical performance – part 3: recommended force limits for machinery operations. london: british standards institute, 2002. 23. mcgill sm. searching for the safe biomechanical envelope for maintaining healthy tissue. pre-meeting workshop, international society for the study of the lumbar spine: the contribution of biomechanics to the prevention and treatment of low back pain, university of vermont, burlington, 1996. 24. hoozemans mjm, kuijer pfm, kingma i, et al. mechanical loading of the low back and shoulders during pushing and pulling activities. ergonomics 2004;47(1):1-18. [http://dx.doi.org/10.1080/00140130310001593577] 40 sajsm vol 19 no. 2 2007 introduction in 2010 south africa will host the soccer world cup for the first time on the african continent. in 1996 the south african national team was ranked 16th in the world. ten years later the south african team was ranked 69th. this gradual slide in ranking has led to apprehension over south africa’s performance in the next world cup finals. 1 part of the perennial public criticism of many south african national team performances concerns the physical fitness of players. for sport scientists to make meaningful contributions to team performance, objective data are needed related to these phenomena. soccer is the most widely played and watched sport in the world. 12,27 mirroring its global popularity is a vast amount of scientific enquiry devoted to soccer. this has included studies on player motion analyses, metabolic profiling of match requirements, anthropometrical and fitness testing and technical skill assessments, 19 involving both elite and non-elite, 22 youth and senior, 5 and male and female players, 6 and even soccer referees. 23 as with most sports, a myriad physical, psychological and technical factors contribute to performance. 2,3,14,23 it is generally accepted that a wide range of physical fitness attributes are vital in soccer, particularly in the modern game. 22,24 players’ physical capacities are even said to contribute to the technical and tactical skills in soccer. 5,23 improved physical capacity had a positive effect on distance covered, number of sprints, and involvement in decisive plays during a soccer match. 14 some researchers report that performance in fitness testing is related to the level of playing ability. 14, 20, 23, 26 furthermore, svensson and drust 24 report that physical performance is an important consideration in player selection. both laboratory and field tests have been used extensively to assess soccer players’ physical performance at both amateur and elite levels. 24 physiological testing may be useful in determining individual strengths and weakness, monitoring changes in training status, and guiding further exercise prescription. 17 tests are frequently performed at the original research article higher log position is not associated with better physical fitness in professional soccer teams in south africa abstract objective. to assess the difference in physical fitness of players in successful versus less-successful professional soccer teams in south africa. design. professional soccer players (n = 140) underwent a battery of tests assessing important physiological components during the early part of their competitive season. players were then separated into two groups on the basis of their teams’ final log position in the premier soccer league (psl) in south africa. players in successful (n = 70) and less-successful (n = 70) teams were in the top four or bottom six positions on the log respectively. descriptive statistics (mean ± standard deviation (sd)) were calculated for each group, and independent t-tests were used to compare the means of the groups for each of the physical tests. main outcome measures. body composition, flexibility, muscle strength-endurance, power, speed, agility, aerobic endurance, and repeat sprint distance. results. there were no significant differences between groups for all measures of body composition, flexibility, repeat sprint distance, and agility. significant differences (p < 0.05) were found for sit-ups, aerobic endurance, and speed, but these were generally small, not meaningful differences in performance. players in successful squads were significantly (p < 0.01) older than those in less-successful teams. conclusions. the results demonstrate that in south africa level of physical fitness is not higher in more-successful compared with less-successful teams in the psl. factors other than physical fitness may be more important in determining successful league performance and discrimicorrespondence: j r clark institute for sport research lc de villiers sport centre university of pretoria 0002 tel: 012-420 6033 fax: 012-420 6099 e-mail: jimmy.clark@up.ac.za nate better between players in teams with different levels of success. improving professional soccer performance may require coaches and trainers to focus more attention on technical and tactical skill development in sport-specific training once an acceptable standard of fitness has been attained. j r clark (bsc hons), ba (hons), cscs institute for sport research, department of biokinetics, sport and leisure sciences, university of pretoria pg40-45.indd 40 7/5/07 10:34:00 am sajsm vol 19 no. 2 2007 41 start and end of the pre-season to evaluate the effectiveness of training preparation. 24 although field tests may provide less direct and accurate measurements than laboratory tests, they have greater specificity. 17 sports performance is frequently regarded as a function of genetic endowment, training and health status, and athlete skill, in various combinations. 17 sport scientists and trainers are often tasked with maximising physical performance with the aim of improving competition success. indeed, some authors have recommended that, at least in european leagues, more focus be directed towards the effective training of players’ physical abilities. 23 the extent to which technical/ tactical versus physical fitness interventions are required remains a difficult question to answer in practice. are similar recommendations justified in a south african context? just how fit a team needs to be to achieve success is important in deciding on coaching and training schedules, training session focus, and player selection. more specifically, the question of whether physical fitness of players is a contributing factor to the difference between successful and less-successful teams in south africa should be addressed. fitness test performance may vary depending on the individual player’s profile, their position of play, and the team’s style of play. 19,23,24 it has been reported that the work rates of elite players are higher than those of non-elite players, and that this is achieved by both higher aerobic and anaerobic rates of metabolism. 23 yet most researchers agree that individual test results cannot be used to conclusively predict performance in match-play due to the complex requirements for soccer success. 24 it is less clear whether team success is associated with the overall physical fitness of the team. stølen et al. 23 reported that the lowest ranked national teams had lower maximal oxygen consumption (vo2max) values than the best national teams. hoff 14 also reported that a relationship exists between average vo2max and team performance in european squads. the purpose of this study was therefore to assess whether there were significant differences in physical fitness between professional soccer players in south african teams placed high and low on the league log. results would be useful for coaching, technical and conditioning staff in directing the allocation of training time. this is particularly important in an era in which competition schedules are increasingly demanding, and available preparation time needs to be used most effectively. methods subjects one-hundred-and-forty players from professional teams in the premier soccer league (psl) in south africa were recruited for the study. the physical testing formed part of the ongoing physical assessment programmes for the teams. only players declared medically fit to participate in all the testing by the team doctors were included. all players were briefed on the purpose, benefits and risks involved in the testing, and all completed written informed consent forms. subjects were assigned to one of two groups based on their teams’ final league position at the end of the season in which they were tested. teams were classified as successful or unsuccessful by finishing in the top four or bottom six positions of the psl log, respectively. procedures data collection took place at the institute for sport research, university of pretoria, during the months of october and november in 2005 and 2006. this falls in the first half of the domestic competitive soccer season, after all teams had been through pre-season training in june and july, and had started the new season in august. this period of the season was marked by 4 7 training sessions per week, of which 3 5 involved focused physical conditioning of 45 90 minutes per session. all testing occurred in a team format, with group instruction and explanation before testing, and strong verbal motivation of players during the tests. testing sessions were completed in a single day on each occasion, with teams being tested on different days. testing was always conducted between 08h00 and 12h00, in the same test order, and with the same rest periods between consecutive tests. anthropometrical, flexibility, and muscle strength-endurance assessments were conducted indoors in a temperature-controlled (~21°c) setting. all other tests were conducted outdoors, with maximum ambient temperatures during testing ranging from 24°c to 27°c. subjects were instructed to arrive for the testing well rested, well hydrated and fed, to avoid caffeinecontaining foods on the day of testing, and to avoid physical exercise on the day prior to the testing. subjects had access to water through the duration of the testing. a standardised general warm-up was administered to the team prior to the outdoor testing. this lasted 15 minutes and consisted of easy running, stretching, dynamic drills, and harder but submaximal acceleration sprints. more specific warm-up and familiarisation drills took place immediately before each of the subsequent tests. anthropometry and body composition the anthropometrical measuring procedures described by norton et al. 18 were used. body mass was measured using a tanita bf-350 electronic scale (tanita corporation, tokyo, japan) and players’ stature was measured using a seca 214 stadiometer (seca corporation, hanover, usa). skinfold thickness (triceps, subscapular, biceps, supra-iliac, calf, thigh, and abdominal) was measured using a harpenden skinfold caliper (baty international, british indicators, west sussex, england). these were summed to obtain the sum of seven skinfolds. 18 percentage body fat was estimated from these measures by predicting body density from the equation by durnin and womersley 7 and then estimating per cent body fat based on the siri formula as described by lohman. 16 flexibility the modified sit-and-reach test 13 was used to assess hip and trunk flexion 9 using a sit-and-reach box. players were inpg40-45.indd 41 7/5/07 10:34:01 am 42 sajsm vol 19 no. 2 2007 structed to stretch their hamstrings and low back prior to the test, after which test procedures were followed as described by hoeger. 13 the total displacement of the fingertips between reach and stretch distance was recorded to the nearest 0.5 cm, and the best of three trials was accepted as the final score. strength-endurance strength-endurance measures included overhand pull-ups, bent-knee sit-ups, and push-ups. maximum pull-ups were assessed with players maintaining a pronated (overhand) grip on a fixed overhead, wall-mounted pull-up bar. hands were placed 5 cm wider than shoulder width. pulling the body up from a hanging, straight-arm position to end with the chin above the bar was considered a legitimate pull-up. players performed the maximum number of repetitions possible without touching the wall or floor. sit-ups were performed with knees bent at 90° and feet secured to the floor. with arms crossed on the chest and hands holding the shoulders, players curled up from a supine position until the elbows touched the knees, and descended until the scapula touched the floor. players performed the maximum number of sit-ups in 2 minutes. the maximum number of push-ups that players could perform in 1 minute was measured. players assumed a prone position with thumbs shoulder-width apart. a legitimate push-up involved pressing the body upward until the elbows were extended with simultaneous ascent of the hips and shoulders. descent required lowering the body with the arms until the elbows were bent to 90° while only the hands and the toes touched the floor. power jumping ability incorporating explosive knee and hip extension was assessed through the vertical jump test. 9 after the generalised warm-up described above, players were instructed to perform light body-weight squats and submaximal jumps in preparation for the maximal-effort jumps, before instruction on test procedure. a vertec device (sports imports, columbus, usa) was securely set on a hard level surface. players stood side-on to the device with their right shoulder in line with the vanes. the test was conducted using the procedures described by ellis et al., 9 and the greatest distance between reach and jump height was recorded to the nearest 1 cm after three trials. players rested between efforts. the athletes’ power output was estimated using the lewis formula using body mass and vertical jump distance, 10 and then divided by body mass to obtain relative power output in w/kg. speed a maximum-effort sprint running test was used to assess players’ speed and acceleration from a stationary position. subjects sprinted on a level, even surface, in a straight line on a natural grass soccer pitch with the subjects wearing full soccer kit. players were briefed on the start procedure and allowed 2 3 submaximal ‘acceleration sprints’ along the test distance. the swift speedlight timing system (alstonville, australia) was used in conjunction with the protocol described by ellis et al. 9 timing gates were placed at chest height at 0 m, 10 m, and 40 m intervals along a straight line. players started 30 cm behind the 0 m mark from a standing start when they were ready, initiating the timer on crossing the 0 m mark, thus eliminating reaction time. the fastest of two trials was recorded to the nearest 0.01 s for 10 m and 40 m. players rested for around 5 minutes between attempts. agility the illinois agility test, adapted and modified by roozen 21 and tossavainen 25 from getchell 11 was used as a measure of agility. the test requires maximal effort acceleration, deceleration and direction change while sprinting between a grid of cones. a level, even surface on a natural grass soccer pitch was used for the test, with the subjects wearing full soccer kit. subjects performed a fast but submaximal run in the required pattern before the first test effort. the swift speedlight timing system (alstonville, australia) was used to measure test time with a timing gate set up at the finish line. players started in the prone position behind the start line. timing was initiated by an audio signal whereupon players got up and sprinted through the predetermined grid of cones. 25 the fastest time of two attempts was recorded. players had about 5 minutes of rest between attempts. aerobic endurance the progressive maximal 20 m multi-stage shuttle run test (mst) was used to assess aerobic power. 15 this test has been widely used to test english football players 24 and is recommended as a test of aerobic endurance by stølen et al. 23 the test was conducted on a non-slip hard court surface. 15 players were instructed to pace their runs along the 20 m shuttle distance according to the audio signal from the recorded compact disc. failure to maintain the required pace for two consecutive shuttles constituted a criterion for a verbal warning. if this continued, players were eliminated from the test. the level and shuttle immediately prior to elimination from the test was recorded as the player’s score. this score was used to estimate vo2max. 15 players were instructed to cool down following the test with 10 minutes of easy jogging, walking and stretching. repeated sprint testing a repeated sprint test was used to assess the ability to perform multiple bouts of high-intensity running between brief periods of rest. 4 a level, even surface on a natural grass soccer pitch was used for the test with the subjects wearing full soccer kit. six lines (marked 0 5) were placed at 5 m intervals. players were required to sprint from the start line to line 1, and back to the start line, then to line 2, back to the start line, and so on. players were instructed to sprint as far as they could in this fashion for 30 s. a whistle blow signalled the start of each shuttle run, with six runs in total, each separated by 35 s of recovery time in which players returned to the start pg40-45.indd 42 7/5/07 10:34:01 am sajsm vol 19 no. 2 2007 43 line. strong verbal motivation was given and players were instructed to sprint as hard as possible. total sprint distance for each 30 s sprint was recorded to the nearest 2.5 m and the distance of the six sprints was summed to obtain the total repeat sprint distance in metres. data analysis standard descriptive statistics (mean ± standard deviation (sd)) were used to characterise the two sets of players. unpaired independent t-tests were used to compare the results of the successful and unsuccessful group means. results were considered significant at p < 0.05. results table i presents the means ± sd of the physical tests of players in the successful and unsuccessful groups. no significant differences were found between the successful and unsuccessful groups in any of the anthropometrical and body composition measures, i.e. mass, stature, sum of seven skinfolds, and percentage body fat. there were also no statistically meaningful differences between players in the successful and unsuccessful groups in terms of sit-and-reach flexibility and vertical jump scores, even when the latter were expressed as power output per kg body mass (16.1 ± 1.1 w/kg v. 15.9 ± 1.1 w/kg). similarly, agility performance (16.29 ± 0.45 s v. 16.35 ± 0.48 s) and total repeat sprint distance (714 ± 39 m v. 716 ± 37 m) were remarkably similar between the successful and less successful groups of players. small and non-significant differences were found between groups for maximum pushups in 1 minute and maximum pull-ups. significant differences were found between groups on 10 m and 40 m sprint times in favour of the more successful teams. differences were also found between groups in estimated vo2max based on the 20 m mst, with the unsuccessful group of players achieving better aerobic endurance performances than players from the successful teams. it should be noted though that the reported standard error of estimation (see) for this test is 5.4 ml/kg/min, 15 which is larger than the modest 1.8 ml/kg/min difference between the means of these groups. the less-successful group also performed more sit-ups in 2 minutes than the successful players. more significant (p < 0.01) differences were found between the groups in terms of age, with players in successful squads being on average ~ 2 years older than their less successful counterparts (25.9 ± 4.3 years v. 23.7 ± 3.9 years). table i. anthropometrical, flexibility, power, strength-endurance, speed, agility, aerobic endurance, and repeat sprint data for players in successful (n = 70) and unsuccessful (n = 70) professional south african soccer teams variable successful* (mean ± sd) unsuccessful† (mean ± sd) age (years) ‡ 25.9 ± 4.3 23.7 ± 3.9 mass (kg) 73.7 ± 9.1 73.1 ± 9.2 stature (cm) 176.3 ± 7.1 177.1 ± 7.5 sum of seven skinfolds (mm) § 56.6 ± 19.4 56.0 ± 17.9 body fat (%) � 13.3 ± 3.5 13.3 ± 3.1 sit-and-reach (cm) 40.2 ± 8.4 37.8 ± 7.7 vertical jump (cm) 54.6 ± 8.5 52.9 ± 7.2 power (w/kg) ii 16.1 ± 1.1 15.9 ± 1.1 maximum sit-ups in 2 min** 73 ± 14 78 ± 13 maximum push-ups in 1 min 44 ± 10 46 ± 12 maximum pull-ups 7 ± 3 7 ± 4 10 m sprint time (s)** 1.86 ± 0.07 1.88 ± 0.07 40 m sprint time (s)** 5.49 ± 0.18 5.57 ± 0.23 illinois agility test time (s) 16.29 ± 0.45 16.35 ± 0.48 estimated vo 2max (ml/kg/min)** †† 51.7 ± 5.1 53.5 ± 4.8 total repeat sprint distance (m) 714 ± 39 716 ± 37 *finishing within the top four positions of the professional soccer league log. †finishing within the bottom six positions of the professional soccer league log. ‡significantly different, p < 0.01. §skinfolds: triceps, subscapular, biceps, supra-iliac, calf, thigh, and abdominal. �based on the siri formula as described by lohman. 16 ii based on vertical jump performance using the lewis formula described by fox and mathews. 10 **significantly different, p < 0.05. †† based on performance in the 20 m multi-stage shuttle run test. 15 pg40-45.indd 43 7/5/07 10:34:01 am 44 sajsm vol 19 no. 2 2007 discussion since players must move their own body mass during running, jumping and direction changes, a high body fat content would appear to be a disadvantage in soccer. 17 physical size could be theorised to be important in winning player contests during the game, but might negatively affect acceleration and nimbleness, arguably more valuable qualities in soccer. these players did appear lean and light, with both groups averaging 13.3% body fat, weighing 73.7 ± 9.1 kg (successful) v. 73.1 ± 9.2 kg (unsuccessful), and both having low sum of seven skinfolds (56.6 ± 19.4 mm v. 56.0 ± 17.9 mm respectively). significant differences in anthropometrical and body composition measures were not apparent between players in the different groups. players need explosive quickness and speed in making decisive runs in defence or attack. explosive power, agility, and balance are often required in winning critical moments or contests within a game. test results in this study were unable to discriminate between players in successful and lesssuccessful squads on the basis of lower back and hamstring flexibility (sit-and-reach test), strength endurance (maximum push-ups, sit-ups and pull-ups), and explosive power (vertical jump). these are widely performed physical fitness tests included in test batteries for sports performance, and soccer in particular. although they may be valuable in assessing flexibility and musculoskeletal function for health-related fitness, it is possible that at the level of elite soccer players, the movement tasks are far removed from the requirements of an actual game. acceleration and running speed are among variables reportedly able to differentiate between levels and positions of play. 24,26 during a soccer match, players generally sprint for average durations of less than 6 seconds. 19 the 10 m and 40 m sprint tests appropriately target this duration of running work, and were therefore expected to highlight more successful players’ ability to get from one point to another more quickly. small significant differences (1.86 ± 0.07 v. 1.88 ± 0.07 s and 5.49 ± 0.18 v. 5.57 ± 0.23 s) were found between groups on these components, but these arguably do not represent meaningful differences in performance. agility is the fitness component that describes the ability to change the direction of body motion rapidly, and results from a combination of a variety of physical components. 24 soccer players continuously change movement direction and body position during a match. the results of this study show no differences between players in successful and less-successful groups, and in fact, show remarkably similar values between these groups in agility performance. it is possible that this is a fundamental component required in soccer, no matter what the level of success. the distance covered by outfield players approximates 10 13 km per game, 23 with variations based on playing position, style of play, and match conditions. 19 the vast majority (90 98%) of the energy required during a soccer match is produced through oxidative metabolism. 5,14 edwards et al. 8 suggest that elite-level soccer performance may be partly determined by aerobic capacity. it is reasonable to expect that elevations in aerobic power and capacity would help to sustain high work rates during a game 19 and that teams with better aerobic endurance are more likely to exert their dominance, and ultimately be more successful. in the current study it is difficult to claim a meaningful difference between the groups considering that the statistically significant difference is much smaller than the error of measurement of the test, as mentioned above. players must be able to recover rapidly between intense bouts of work as the exercise pattern in soccer involves multiple sprints. 19 this was assessed through the repeat sprint test. no significant differences were found between players from teams that were either successful or unsuccessful. the results of this study seem to suggest that these common physical fitness tests were unable to discriminate between players of teams placed high or low on the psl log. in other words, although the fitness scores of players in this study may be different from those of untrained individuals or players in different leagues, successful and unsuccessful teams within the same professional league could not be separated on the basis of physical fitness. factors other than physical fitness may be more important in determining success in professional soccer, at least in south africa. the most obvious of these include technical skill, tactical sense and ability, style of play, player motivation and frame of mind. a number of limitations in the current study may warrant consideration. body composition estimations may have been confounded by the wide ethnic influence in the squads. the outdoor testing was associated with ambient condition changes such as wind velocity, ambient temperature and relative humidity, which may well have affected sprint, repeat sprint, and endurance running performance. it is possible that the level of activity between players differed at the time of measurement in terms of content of early season training sessions, and that this influenced performance in the tests. alternatively, other physical fitness tests that better replicate soccer requirements 5 may produce more significant differences between successful and less-successful squads. finally, these players were tested in the first half of the season, with changes in physical fitness status and squad profile likely during the course of a full season. nonetheless, reilly 19 reported little fluctuation in physical fitness profiles of soccer players once the competitive season gets underway, as match play and general training maintain the training status at a relatively constant level. despite these potential limitations it is difficult to ignore that while no physical fitness parameter significantly separated higher and lower-ranked teams, the one measured parameter that may be associated with some form of technical experience – age – did show a highly significant difference between groups. players in successful squads were on average 2.2 years older than in less-successful squads. it seems plausible that technical and tactical skill, and therefore pg40-45.indd 44 7/5/07 10:34:01 am sajsm vol 19 no. 2 2007 45 team success would be better with the increased experience gained by older players. conclusions these results support those of other studies of individual players in which the test results of non-elite players were comparable to those of elite players. 22 it seems that in the south african professional soccer setting, league performance is not dependent on superior physical fitness within that league. as noted by reilly et al., 20 players may not require exceptional ability in any physical fitness component, but should possess a reasonably high ability in all areas. it may be that provided a particular fitness standard is achieved, factors such as technical skill, tactical sense and ability, style of play, and player motivation may contribute more to the difference in log position at the end of a season. it is possible that the factors most limiting further improvement in soccer performance are of a skill-type nature, and should be given preferential attention. this may be different from the situation in other countries, and is in contrast to the results of studies using players in overseas leagues. 2,9,14,23,24,26 managers, coaches, and trainers should consider this when planning training and conditioning sessions for teams. emphasis on technical and tactical work within sessions and incorporating these elements into physical conditioning sessions may better target the preparation requirements in soccer. further research should focus on whether other physical fitness tests or tests of technical skill more distinctly separate players in successful and less successful teams. acknowledgements the author would like to thank the staff of the institute for sport research, university of pretoria, for their assistance in data collection; and the management, coaching staff, and players of the teams who participated in the study. references 1. anonymous. parreira: i want south african success. september 2006. www.fifa.com (last accessed 1 february 2007). 2. åstrand po, rodahl k, dahl ha, strømme sb. textbook of work physiology: physiological bases of exercise. 4th ed. champaign, ill.: human kinetics, 2003. 3. bangsbo j. the physiology of soccer: with special reference to intense intermittent exercise. acta physiol scand 1994; 15: suppl 619, 1-156. 4. boddington mk, lambert mi, st clair-gibson a, noakes td. reliability of a 5-m shuttle test. j sports sci 2001; 19: 223-8. 5. chamari k, hachana y, ahmed yb, et al. field and laboratory testing in young elite soccer players. br j sports med 2004; 38:191-6. 6. davis ja, brewer j. applied physiology of female soccer players. sports med 1993; 16: 180-9. 7. durnin jvga, womersley j. body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. br j nutr 1974; 32: 77-97. 8. edwards am, macfadyen am, clark n. test performance indicators from a single soccer specific fitness test differentiate between highly trained and recreationally active soccer players. j sports med phys fitness 2003; 43: 14-20. 9. ellis l, gastin p, lawrence s, et al. protocols for the physiological assessment of team sport players. in: gore cj, ed. physiological tests for elite athletes. lower mitcham, australia: human kinetics, 2000: 128-44. 10. fox el, mathews dk. the interval training: conditioning for sports and general fitness. philadelphia: wb saunders, 1974. 11. getchell b. physical fitness: a way of life. 3rd ed. new york: macmillan, 1985. 12. hillis s. preparations for the world cup. br j sports med 2000; 32: 95. 13. hoeger wk. principles and labs for physical fitness and wellness. englewood, colo.: morton, 1991. 14. hoff j. training and testing physical capacities for elite soccer players. j sports sci 2005; 23: 573-82. 15. lèger la, lambert ja. maximal multistage 20-m shuttle run test to predict vo2max. eur j appl physiol 1982; 49:1-12. 16. lohman tg. advances in body composition assessment. champaign, ill.: human kinetics, 1992. 17. macdougall, jd, wenger ha. the purpose of physiological testing. in: macdougall, jd, wenger ha, green hj, eds. physiological testing of the high-performance athlete. 2nd ed. champaign, ill.: human kinetics, 1991. 18. norton k, marfell-jones m, whittingham n, et al. anthropometric assessment protocols. in: gore cj, ed. physiological tests for elite athletes. lower mitcham, australia: human kinetics, 2000: 66-85. 19. reilly t. football. in: reilly t, secher n, snell p, williams c, eds. physiology of sports. london: e & fn spon, 1990: 371-425. 20. reilly t, bangsbo j, franks a. anthropometric and physiological predispositions for elite soccer. j sports sci 2000; 18: 669-83. 21. roozen m. action-reaction: illinois agility test. nsca’s performance training journal 2004; 3(5): 5-6. 22. siegler j, robergs r, weingart h. the application of soccer performance testing protocols to the non-elite player. j sports med phys fitness 2006; 46: 44-51. 23. stølen t, chamari k, castagna c, wisløff u. physiology of soccer: an update. sports med 2005; 35: 501-36. 24. svensson m, drust b. testing soccer players. j sports sci 2005; 23: 60118. 25. tossavainen m. testing athletic performance in team and power sports. oulu, finland: newtest oy, 2004. 26. tumilty d. protocols for the assessment of male and female soccer players. in: gore cj, ed. physiological tests for elite athletes. lower mitcham, australia: human kinetics, 2000: 356-362. 27. wilsey s. the beautiful game. national geographic 2006; 209: 42-8. pg40-45.indd 45 7/5/07 10:34:02 am original research 8 sajsm vol. 25 no. 1 2013 background. coaching strategies for effective technique and injury prevention have been proposed for the tackle. despite this, little is known about current coaching attitudes and the behaviours of coaches towards proper contact technique in the tackle, especially at the junior level. objective. to report on the attitudes and behaviours of junior rugby union coaches towards coaching of proper contact technique in the tackle. methods. seven coaches of the top 8 rugby-playing schools (premier division) in the western province rugby union participated in the study (representing 88% of the entire population of top-level junior coaches in the region). coaches completed a questionnaire, modelled on previous research, surveying attitudes and behaviours towards tackling. results. proper technique for injury prevention was rated as very important (57%) and important (29%), with 14% undecided. proper technique to improve performance was rated as very important (57%) and important (43%). to further develop coaching knowledge and to develop new training methods, ‘coaching colleagues’ (very much – 71%; mean rating 4.7; 95% ci 4.3 5.2) was rated as the most often used. conclusion. collectively, the coaches in this study demonstrated a positive attitude towards injury prevention and performance. additional means of communicating information to coaches, other than the traditional channels, have also been highlighted here. s afr j sm 2013;25(1):8-11. doi:10.7196/sajsm.459 attitudes and behaviours of top-level junior rugby union coaches towards the coaching of proper contact technique in the tackle – a pilot study s hendricks, m sarembock mrc/uct research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, cape town, south africa s hendricks, phd department of health and rehabilitation sciences, division of physiotherapy, faculty of health sciences, university of cape town, cape town, south africa m sarembock, bsc (physiotherapy) corresponding author: s hendricks (sharief.hendricks01@gmail.com) the tackle is an important component of rugby union. the ability of a player to engage and tolerate frequent contact in the tackle, whether as a ball-carrier or tackler, influences the performance of the team and exposes players to a high risk of injury. therefore, in part, for safe and successful participation in rugby union, coaching of tackle contact techniques is essential.[1,2] the knowledge, attitude and behaviour of coaches have been highlighted as key instruments in the implementation of injuryprevention strategies in junior sports.[3,4] in view of this, researchers have studied coaches’ knowledge, attitudes and behaviours to understand the context in which to translate evidence-based injuryprevention training programmes.[2,5-8] for example, premier division coaches in the australian football league generally ranked injury prevention lower than the needs of general training sessions and team performance.[8] a sample of junior rugby union coaches had limited knowledge of injury mechanisms and injury management.[2] the same sample of coaches identified the tackle as the facet of play where most injuries occur, but at the same time, the perception of increasing technical knowledge for ball-carrying contact techniques and tackling techniques was reported less frequently.[2] for reasons mentioned earlier, the tackle in rugby union has received much attention in the literature recently, with coaching strategies for effective technique and injury prevention being proposed.[1] despite this, very little has been documented on the current coaching attitudes and behaviours of coaches towards proper contact technique in the tackle, especially at the junior level. therefore, the purpose of this study was to report on the attitudes and behaviours of junior rugby union coaches towards the coaching of proper contact technique in the tackle. it should be noted that this study acted as a pilot for a larger study, the aims of which are not only to examine self-reported data on coach attitudes and behaviour, but also to directly observe coach behaviour during training sessions. methods the coaches of the top 8 rugby-playing schools (premier division) in the western province rugby union were approached for this study. mailto:sharief.hendricks01@gmail.com sajsm vol. 25 no. 1 2013 9 seven coaches gave informed consent to participate, representing 88% of the entire population of top-level junior coaches in the region. the university of cape town research ethics committee approved the study, and all coaches provided informed consent before participating. the questionnaire used in the study was modelled on previous research into the attitudes and behaviours towards tackling.[9] the self-reported questionnaire was aimed at gaining insight into attitudes and behaviours of coaches towards the coaching of proper contact technique in the tackle, but without burdening the coach. with this in mind, the questionnaire consisted of 2 background questions (surveying the highest level coached, experience and accredited coaching qualifications), 2 attitudinal and 3 behavioural questions. all questions were closed-ended, comprised of a list of possible answers (items) and response categories, with a 5-point ordinal likert scale represented by a numerical value. coaches had to rate the importance and quantity of each item in the question. despite studying 88% of the population, the sample size (n=7) was too low to conduct interpretive statistics; therefore, descriptive statistics were reported. data were expressed as means with 95% confidence intervals (cis) and/or as percentages of the scores on the likert scale. results coaching background information mean coaching experience was 14 years (standard deviation (sd) ±6). seventy-one per cent (n=5) of the coaches had a level 2 coaching qualification and 14% (n=1) had a level 1 qualification. twentynine per cent (n=2) of the coaches had a tertiary qualification, and 29% completed an exercise-training accreditation. all coaches had completed the boksmart training course.[10] attitude fifty-seven per cent of coaches rated proper technique to prevent injury as very important, 29% rated proper technique to prevent injury as important, and 14% were undecided on the matter. in comparison, 57% of coaches indicated proper technique to improve tackling performance as very important and the remaining 43% indicated proper technique to improve tackling performance as important. when asked to rate the importance of proper technique for the different phases of play, 86% of coaches reported ‘ball-carrying’, ‘rucking’ and ‘ball-handling’ as very important (table 1). for the same question, 71% reported ‘tackling’ and ‘scrumming’ as very important. ‘line-outs’ (57% very important), ‘mauling’ (57% very important) and ‘falling to ground’ (43% very important) were not rated as important. when the different phases of play were ranked according to mean rating, ‘ballcarrying’ (4.9; 95% ci 4.5 5.2), ‘scrumming’ (4.7; 95% ci 4.2 5.2) and ‘tackling’ (4.7; 95% ci 4.3 5.2) were ranked most important (table 1). proper technique for ‘falling to ground’ (4; 95% ci 2.9 5.1) was rated as the least important phase of play. behaviour to further develop coaching knowledge and to develop new training methods, ‘coaching colleagues’ (71% very much; mean rating 4.7; 95% ci 4.3 5.29), ‘televised rugby matches’ (very much – 57%; mean rating 4.6; 95% ci 4.1 5.1) and ‘attending live rugby matches’ (57% very much; mean rating 4.4; 95% ci 3.9 4.9) were rated as the most often used, whereas ‘attending workshops’ (29% a little; 29% a fair amount; mean rating 2.9; 95% ci 1.6 4.1), ‘attending formal coaching/physical education courses’ (29% a little; 57% a fair amount; mean rating 2.9; 95% ci 2.2 3.5), and ‘newspapers’ (43% not at all; mean rating 2.4; 95% ci 0.9 3.9) were ranked the least-often used (table 2). coaching methods that included the entire team, whether as ‘verbal instruction to the entire team’ (71% very much; 21% much), ‘demonstration to the entire team’ (71% very much; 21% much), or ‘identifying a team problem and coaching the team accordingly’ (57% very much; 43% much) were used more often than focusing on individual players. table 3 ranks the mean ratings of importance for different drills and equipment used to train the tackle. mean ratings were ranked for (i) injury prevention, and (ii) improving performance. discussion the aim of this article was to report on the attitudes and behaviours of junior top-level rugby union coaches. seven out of the 8 top rugbyplaying schools were surveyed, representing 88% of the population. the reported importance of proper technique to lower the risk of injury or improve performance was positive as most coaches rated table 1. attitudes (importance) toward proper technique during the different phases of play* phase of play very important % somewhat important % undecided % not too important % not at all important % importance mean (95% ci) ball carrying 86 14 4.9 (4.5 5.2) scrumming 71 29 4.7 (4.2 5.2) tackling 71 29 4.7 (4.3 5.2) rucking 86 14 4.7 (4.0 5.4) ball handling 86 14 4.6 (3.5 5.6) line-outs 57 29 14 4.3 (3.3 5.3) mauling 57 29 14 4.2 (3.7 5.2) falling to the ground 43 29 14 14 4.0 (2.9 5.1) *data are reported as percentage frequencies (%) in each response category and mean ratings of importance with 95% confidence intervals (cis). 10 sajsm vol. 25 no. 1 2013 it either very important or important, except for one coach who indicated that he was undecided whether or not proper technique reduces the risk of injury. interestingly, the coach who was undecided on the matter was also the most experienced coach (more than 20 years’ experience) and the least qualified. proper techniques towards the contact phases (ball-carrying, scrumming, tackling and rucking) of the game were ranked as the most important. almost all coaches indicated that falling to ground was important; 28% were either undecided or rated it as not too important. in a similar study on junior rugby union coaches, the most frequently table 2. reported use of resources to further coaching knowledge and develop new training techniques* resource very much % much % a fair amount % a little % not at all % importance mean (95% ci) coaching colleagues 71 29 4.7 (4.3 5.2) televised rugby matches 57 43 4.6 (4.1 5.1) attending live rugby matches 57 43 4.4 (3.9 4.9) sport/rugby shows on tv 100 4.0 your own playing experience 50 17 17 17 4.0 (2.7 5.3) internet 14 57 14 14 3.7 (2.8 4.6) rugby training videos 14 43 29 14 3.6 (2.7 4.5) rugby training videos 14 43 29 14 3.6 (2.7 4.5) rugby training books 57 29 14 3.4 (2.7 4.2) coaching clinics 29 71 3.3 (2.8 3.7) rugby magazines 29 43 14 14 2.9 (1.9 3.8) attending workshops 14 14 29 29 14 2.9 (1.6 4.1) attending formal coaching/ physical education courses 14 57 29 2.9 (2.2 3.5) newspapers 14 14 14 14 43 2.4 (0.9 3.9) *data are reported as percentage frequencies (%) in each response category and mean ratings of importance with 95% confidence intervals (cis). table 3. mean ratings of importance of drills used by coaches when training the tackle for injury prevention and improving performance* injury prevention improving performance drill mean (95% ci) drill mean (95% ci) giving verbal instruction 4.57 (3.84 5.3) giving verbal instruction 4.29 (3.13 5.45) using a shield 4.29 (3.59 4.98) body armour 4.00 (2.37 5.63) tackle bag 3.86 (2.50 5.20) using tackle bag 3.86 (2.50 5.21) tackle drill combined with ball-skill exercise 3.86 (2.61 5.10) live tackling in a 1 v. 1-player grid 3.83 (2.29 5.38) tackle drill combined with fitness conditioning 3.86 (2.86 4.84) using a shield 3.71 (2.69 4.74) live tackling in a 1 v. 1-player grid 3.71 (2.55 4.87) tackle drill combined with fitness conditioning 3.71 (2.83 4.59) tackling drill combined with reaction exercise 3.71 (2.55 4.87) contact practice match 3.71 (2.69 4.74) body armour 3.67 (2.08 5.25) tackling drill combined with reaction exercise 3.71 (2.55 4.87) demonstration 3.57 (2.39 4.75) tackle drill combined with ball-skill exercise 3.43 (2.38 4.48) contact practice match 3.43 (2.70 4.16) demonstration 3.43 (2.25 4.61) tackling drill combined with vision exercise 3.43 (2.38 4.48) tackling drill combined with vision exercise 3.29 (2.26 4.31) *data are reported as mean ratings with 95% confidence intervals (cis). sajsm vol. 25 no. 1 2013 11 reported phases of play that coaches perceived that they needed more technique knowledge on were scrumming, mauling, line-outs and rucking.[2] in the same study, the least frequently reported phases of play were ball-carrier fall technique, ball-carrier contact technique, and tackling technique.[2] resources most often used by the coaches to increase coaching knowledge and to develop new training drills were colleagues, televised rugby matches and attendance at live rugby matches. the effect of peer interaction on implementing injury prevention programmes (correct landing technique in netball) has been highlighted recently. white et al.[6] showed that although coaches supported the need to teach players correct landing technique, they were not sure if their colleagues were actually doing so. from this finding, it was suggested that coach education programmes should include coach role-models, as social pressure from peers may influence coaches’ intentions to deliver injuryprevention programmes.[6] observing rugby matches (whether televised or live) as a coaching resource suggests that coaches prefer to use their own analysis of matches as a guide for setting up training. least-often used resources for developing coaching were attending workshops, attending formal coaching/physical education courses and newspapers. in contrast, community-level junior netball coaches considered coachtraining workshops and/or coach accreditation courses to be the best way to encourage coaches to use injury-prevention programmes.[7] verbal instruction and the use of padded equipment (shield, bag and body armour) were ranked as the most important drills to use when training the tackle, whether to reduce the risk of injury or to improve performance. the use of padded equipment may reduce the risk of injury in training and aid the development of a player’s tackle technique. [1] with that said, it has been suggested that a more advanced player may benefit more (from an injury-prevention and performance perspective) by training in a more ecologically valid setting (e.g. live 1 v. 1 tackling).[1,9] conclusion collectively, the coaches in this study demonstrated a positive attitude towards injury prevention and performance. coaches should be informed about the phases of play with increased risk of injury, and training drills to mitigate this risk should be communicated. ways to improve conventional modes of coach training (i.e. workshops, formal coaching courses) need further investigation, particularly with the goal of making training courses more attractive and useful for coaches. in addition, research into other means of communicating information to coaches must be emphasised (e.g. coaching role-models).[6] acknowledgments. the authors wish to thank the coaches who participated in the study. conflicts of interest. the authors have no conflicts of interest to declare. references 1. hendricks s, lambert m. tackling in rugby: coaching strategies for effective technique and injury prevention. int j sport sci coach 2010;5(1):117-136. [http:// dx.doi.org/10.1260/1747-9541.5.1.117] 2. carter af, muller r. a survey of injury knowledge and technical needs of junior rugby union coaches in townsville (north queensland). j sci med sport 2008;11(2):167173. [http://dx.doi.org/10.1016/j.jsams.2007.01.004] 3. finch c. a new framework for research leading to sports injury prevention. j sci med sport 2006;9(1-2):3-9. [http://dx.doi.org/10.1016/j.jsams.2006.02.009] 4. donaldson a, poulos rg. planning the diffusion of a neck-injury prevention programme among community rugby union coaches. br j sports med; 2013 (in press). [http://dx.doi.org/10.1136/bjsports-2012091551] 5. finch cf, white p, twomey d, ullah s. implementing an exercise-training programme to prevent lower-limb injuries: considerations for the development of a randomised controlled trial intervention delivery plan. br j sports med 2011;45(10):791-796. [http://dx.doi.org/10.1136/bjsm.2010.081406] 6. white pe, otago l, saunders n, et al. ensuring implementation success: how should coach injury prevention education be improved if we want coaches to deliver safety programmes during training sessions? br j sports med 2013 (in press). [http://dx.doi. org/10.1136/ bjsports-2012-091987] 7. saunders n, otago l, romiti m, donaldson a, white p, finch c. coaches’ perspectives on implementing an evidence-informed injury prevention programme in junior community netball. br j sports med 2010;44(15):1128-1132. [http://dx.doi. org/10.1136/bjsm.2009.069039] 8. twomey d, finch c, roediger e, lloyd dg. preventing lower limb injuries: is the latest evidence being translated into the football field? j sci med sport 2009;12(4):452456. [http://dx.doi.org/10.1016/j.jsams.2008.04.002] 9. hendricks s, jordaan e, lambert m. attitude and behaviour of junior rugby union players towards tackling during training and match play. safety sci 2012;50(2):266284. [http://dx.doi.org/10.1016/j.ssci.2011.08.061] 10. viljoen w, patricios j. boksmart – implementing a national rugby safety programme. br j sports med 2012;46(10):692-693. [http://dx.doi.org/10.1136/ bjsports-2012-091278] http://dx.doi.org/10.1260/1747-9541.5.1.117] http://dx.doi.org/10.1260/1747-9541.5.1.117] http://dx.doi.org/10.1016/j.jsams.2007.01.004] http://dx.doi.org/10.1016/j.jsams.2006.02.009] http://dx.doi.org/10.1136/bjsports-2012-091551] http://dx.doi.org/10.1136/bjsm.2010.081406] http://dx.doi.org/10.1136/bjsports-2012-091987] http://dx.doi.org/10.1136/bjsports-2012-091987] http://dx.doi.org/10.1136/bjsm.2009.069039] http://dx.doi.org/10.1136/bjsm.2009.069039] http://dx.doi.org/10.1016/j.jsams.2008.04.002] http://dx.doi.org/10.1016/j.ssci.2011.08.061] http://dx.doi.org/10.1136/bjsports-2012-091278] http://dx.doi.org/10.1136/bjsports-2012-091278] issn 1015-5163 a peer reviewed publication of the south african sports medicine association www.sajsm.org.za sports medicine the south african journal of volume 26 | number 2 | june 2014 http://www.sajsm.org.za sajsm 499.indd 114 sajsm vol. 25 no. 4 2013 case report osteoid osteomas are benign osteoblastic tumours encountered relatively commonly among skeletal lesions. despite distinct clinical �ndings, atypical presentations make for a challenging or delayed diagnosis which may negatively a�ect a patient’s quality of life in the interim. we present the case of a young female rugby player with a subperiosteal osteoid osteoma of the distal �bula – a rare location for this type of tumour. s afr j sm 2013;25(4):114-115. doi:10.7196/sajsm.499 osteoid osteoma of the �bula in a female rugby player m w j meirhaeghe,1,2 md, mmed (phys med & rehab); p l viviers,1 mb chb, mmedsc, msc (sports med); j h kirby,1 mb chb, msc (sports med); j t viljoen,1 bsc physiotherapy, mphil (exerc sci) 1 stellenbosch university, campus health services and the centre for human performance sciences, stellenbosch, south africa 2 catholic university of leuven, department of physical health and rehabilitation, leuven, belgium corresponding author: p l viviers (plv@sun.ac.za) osteoid osteomas (oos) may account for almost 12% of all benign bone tumours.[1] �ese skeletal neoplasms are most common among young patients (aged 10 30 years) and there is also a strong male preponderance, with a 3:1 male to female ratio.[2,3] classically, oo presents as an intracortical lesion of the sha� occurring in the long bones; however, its location has also proven to be subperiosteal, endosteal and even medullary, albeit less common.[2,4] �e most frequently a�ected sites include the femur and tibia (roughly 50% of all cases), while less regular manifestations include the humerus, spinal column and phalanges of the hands and feet.[2-4] morphologically, tumours are characterised by an osteoid-rich central nidus embedded in a �brous stroma of vascular connective tissue;[2,5] this rarely exceeds 2 cm in diameter and is surrounded by a zone of sclerotic bone tissue due to reactive bone formation.[3,6,7] patients invariably complain of pain that is most severe at night and which is usually relieved with salicylates or non-steroidal anti-in�ammatory drugs (nsaids).[3] local tenderness is typically the only �nding during physical examination, although warmth, swelling and erythema are also possible, albeit less common.[2] on the whole, from a prognostic standpoint, some oo cases have been known to regress spontaneously;[2,8] however, the majority require surgical intervention. we report the case of a young female rugby player with a subperiosteal oo located within the distal fibula. we wish to emphasise that unusual presentations of oo may be misleading for clinical practitioners, and can even result in inaccurate diagnoses. case report a 23-year-old female elite rugby player presented with longstanding le� lateral lower-leg pain while performing high-speed running. �ere was no long-term improvement with rest, physiotherapy or treatment with nsaids. overall, the patient’s medical history was unremarkable and there was no associated nocturnal pain. the initial physical examination showed slight tenderness upon palpation of the distal �bula as well as discomfort during resisted eversion of the foot. �e patient experienced pain when performing one-leg hops as well as discomfort when a vibrating tuning fork was placed over the area. plain radiographs showed a discrete hypodensity on the medial side of the distal fibula (fig. 1a). after further in-depth investigation, magnetic resonance imaging (mri) revealed oedema adjacent to a lesion in the bone (fig. 1b). finally, a computed tomography (ct) scan con�rmed the presence of a cystic tumour with surrounding osteosclerosis located just below the periosteum (fig. 1c). fig. 1. (a) anteroposterior radiograph and (b) magnetic resonance imaging of the osteoid osteoma situated within the le� distal �bula. (c) a cross-sectional computed tomography scan shows the clearly demarcated subperiosteal lesion within the distal medial �bula. sajsm vol. 25 no. 4 2013 115 based on these �ndings, the tumour was excised surgically using a posterolateral approach to the distal fibula. following successful removal of the bone mass, further inspection revealed characteristic features of a nidus, which was con�rmed histologically as being an oo. mobilisation with partial weight-bearing for six weeks and physiotherapist-guided functional rehabilitation took place. the eventual outcome a�er three months was that the patient was able to run without pain and returned to play. discussion since oo can occur at a wide variety of locations and is often accompanied by a lack of radiological findings, diagnosis can be complex, and in many instances even overlooked.[7] we encountered a similar problem, considering that the �bula is a rare localisation for an oo and that our patient displayed an atypical presentation at �rst (i.e. lack of nocturnal pain and failure to respond to nsaids). subsequently, a number of different diagnoses were considered, including bony stress reaction, fibular stress fracture, as well as tendinopathy of the peroneal tendons. less likely considerations were impingement syndrome, sinus tarsi syndrome, dislocation of the peroneal tendons and referred pain. lastly, infections and tumours were also considered; however, the clinical presentation thereof made these options less likely. plain radiography is usually the most cost-e�ective examination and is o�en also all that is required to ensure the accurate diagnosis of oo. nonetheless, it should be noted that during the �rst few months a�er the onset of pain, initial radiographs o�en appear to be normal, which can be misleading. as a result, it is useful to repeat a radiograph if an oo is suspected. we found this to be valid, considering that we initially took a plain radiograph that was reported as normal. however, retrospectively, a discrete hypodensity could be observed. furthermore, the use of detailed imaging techniques such as ct and mri is invaluable when it comes to precise localisation of the tumour and in making a de�nitive diagnosis. first-line medical treatment for this syndrome essentially consists of proper pain management through the use of aspirin or nsaids. still, many patients are unable to continue with this type of treatment due to uncontrolled pain or contraindications to nsaid use. �ere are also several available surgical treatment options for effective excision of the tumour. traditionally, the treatment of choice has been open surgery with unroo�ng and curettage; however, a number of newer, less invasive techniques such as ct-guided percutaneous treatment are also being used and can have a primary cure rate of 100%.[2,8] regardless of the method of treatment, exact localisation of the lesion, before and during the procedure, is a very important determinant of success. conclusion �e subperiosteal region of the distal �bula is an uncommon location for an oo. clinical presentation and radiological �ndings can be misleading, which often results in a delay in diagnosis. in some instances, this phenomenon may even masquerade as an alternative form of pathology or injury. ultimately, delayed diagnosis or misinterpretation of clinical signs and symptoms have the potential to a�ect early clinical decision-making processes governing optimal patient management. as a result, oo should always be considered when pain persists, even if initial x-rays appear to be normal. �e goal of treatment is rapid and enduring pain relief, but also a safe return to sport in athletic populations. acknowledgements. dr rvp de villiers from van wageningen and partners radiology practice for the images. references 1. dahlin dc, unni kk. bone tumors: general aspects and data on 8542 cases. 4th ed. �omas, spring�eld, 1987:88-101. 2. lee eh, sha� m, hui jhp. osteoid osteoma: a current review. j pediatr orthop 2006;26:695-700. 3. greenspan a. benign bone-forming lesions: osteoma, osteoid osteoma and osteoblastoma. clinical, imaging, pathologic and di�erential considerations. skeletal radiol 1993;22(7):485-500. 4. kayser f, resnick d, haghighi p, et al. evidence of the subperiosteal origin of osteoid osteomas in tubular bones: analysis by ct and mr imaging. am j roentgenol 1998;170:609-614. 5. chronopoulos e, xypnitos fn, nikolaou vs, et al. osteoid osteoma of a metacarpal bone: a case report and review of the literature. j med case rep 2008;2:285-288. 6. ja�e hl. osteoid osteoma of bone. radiology 1945;45:319. 7. chai jw, hong sh, choi jy, et al. radiologic diagnosis of osteoid osteoma: from simple to challenging �ndings. radiographics 2010;30(3):737-749. 8. cantwell cp, obyrne j, eustace s. current trends in treatment of osteoid osteoma with an emphasis on radiofrequency ablation. eur radiol 2004;4(4):607-617. sajsm vol 19 no. 4 2007 91 introduction locomotor training for patients with spinal cord injuries has been investigated in the usa and europe. 2,9 it is a relatively new form of rehabilitation in south africa and to our knowledge no studies have been reported on its use in this country. this is a case study of a 24-year-old male diagnosed on 8 september 2006 with a c6 motor complete but sensory incomplete spinal cord injury (sci). on 11 september 2006 a c7 vertebrectomy, bone graft, anterior fusion and internal fixation was performed. from 18 september to 19 december he received inpatient therapy for mobility and self-care skills. on discharge he remained sensory incomplete but some motor function had returned in the right ankle. on 22 february 2007 locomotor training began. the patient was hoisted in an alpine climbing harness (black diamond, usa) attached to an overhead tripod frame placed above a treadmill. assisted walking began with two therapists manually moving the legs at 0.4 km.h-1. in order for the stepping to be consistent a metronome was used. initially the patient could complete a total of 3 minutes 20 seconds of walking in two bouts of 1 minute and 2 minute 20 seconds respectively, at a speed of 0.4 km.h-1. the patient could not stand up with the aid of a walking frame. strength in the quadricep and hamstring muscles was measured bilaterally on the biodex isokinetic dynamometer (biodex medial systems, new york) in passive mode. peak torque was measured at a speed of 5°.s-1 before and after 1 year of therapy (table i). locomotor training was performed 5 days per week as part of an exercise routine. the exercise routine also consisted of upper body cycle ergometry, mat exercises, core stability strengthening and upper body strength training. the entire therapy regimen and progression can be seen in table ii. during the year, for 4 weeks, intermittently, exercise sessions were not attended, either due to the patient being ill or the centre being closed. after 1 year the subject completed 10 minutes of assisted walking without rest and 20 minutes of assisted walking altogether. furthermore, the subject could walk 8 metres continuously with modified crutches. discussion the conventional approach to rehabilitation in patients with spinal cord injury has been to adapt the environment to the patient. this is known as the ‘compensatory model’ and presupposes that the spinal cord is not malleable and capable of recovery. 2 in contrast, the ‘recovery model’ is based on the premise that the spinal cord is malleable and capable of recovery. 2 in the usa complete spinal transection (t12 t13) was performed in adult cats. 8 this caused complete loss of locomotor function in the hindlegs. the injured cats underwent training which consisted of walking on a treadmill for 30 minutes per day, 5 days per week for 5 7 months with therapists manually assisting their hindlegs. five out of the 8 trained cats improved sufficiently to locomote (bearing their full body weight) for 10 20 minutes. 8 a study using rats has also demonstrated the ability of the spinal cord to respond to stimuli without contact with the cerebellum. 3 these studies demonstrate that the spinal cord has a significant level of plasticity in mammals. behrman et al. (2006) reviewed the studies on locomotor training and the injured human spine. 2 most have been case studies or studies with no control group and therefore their results have limited interpretability. there has only been one randomised clinical trial in this population group. 6 this was a multicentre trial and found no difference in fim-l scores (a walking ability score) and walking speeds between a locomotor training group and an overground mobility control group. fim-l score and walking speed were the primary outcome measures but walking distance was not reported. it is important to note that locomotor training cannot be done in an ad hoc manner. afferent input to the spinal cord during locomotor training is important in order for training to be effective. 2 afferent input includes hip extension position during the transition from stance to swing phase (the hip should be in extension), heel strike and load on the lower limb. 5,2 maximal load should be taken on the lower extremities with minimal load on the upper extremities. 4 increased upper extremity weight bearing resulted in decreased emg activity in the lower limbs. 4 case study locomotor training as part of a rehabilitation programme for patients with spinal cord injury – a case study correspondence: bridget marianne parr cape peninsula university of technology barklay davies building highbury road mowbray 7700 tel: 021-680-1573 fax: 021-680-1562 cell: 084 685 7294 e-mail: parrb@cput.ac.za b m parr (msc(med) exercise science) r gamieldien (btech (sport management)) s e h davies (d phil (human movement science), m ergs (ergonomics) cape peninsula university of technology sajsm vol 20 no. 3 2008 91 pg91-92.indd 91 10/17/08 12:57:29 pm a further challenge to this kind of therapy is the physical strain therapists are subjected to. two therapists sit on the side of the treadmill and manually lift the patient’s limbs. the limbs are lifted at the end of stance phase and then propelled forward and placed down in heel strike. this action tends to place strain on the lower back. there have been some recent developments in robotic assistive devices which take the place of the therapists, 7 but they are very costly. in conclusion, locomotor therapy formed part of a regimen that resulted in the patient being able to walk with modified crutches. this level of movement transferred into the patient being able to perform more activities of daily living. future challenges to improved patient care are randomised multi-centre controlled trials designed to test the efficacy of duration, frequency and intensity of this type of training on the multiple classifications of spinal cord injuries. furthermore, from a technology perspective, robotic assistive devices that can aid therapy for patients with spinal cord injuries should be developed. references 1. barbeau h and rossignol s. recovery of locomotion after chronic spinalization in the adult cat. brain res 1987; 412: 84-95. 2. behrman al, bowden mg, nair pm. neuroplasticity after spinal cord injury and training: an emerging paradigm shift in rehabilitation and walking recovery. phys ther 2006; 86: 1406-25. 3. buerger aa, fennessy a. long-term alteration of leg position due to shock avoidance by spinal rats. exp neurol 1971; 30: 195-211. 4. dietz v, colombo g, jensen l, baumgartner l. locomotor capacity of spinal cord in paraplegic patients. ann neurol 1995; 37: 574-82. 5. dietz v, harkema sj. locomotor activity in spinal cord-injured persons. j appl physiol 2004; 96: 1954-60. 6. dobkin b, apple d, barbeau h, basso m, behrman a, deforge d. weightsupported treadmill vs overground training for walking after acute incomplete sci. neurology 2006; 66: 484-93. 7. hornby tg, zemon dh, campbell d. robotic-assisted, body-weight supported treadmill training in individuals following motor incomplete spinal cord injury. phys ther 2005; 85: 52-66. 8. lovely rg, gregor rj, roy rr, edgerton vr. effects of training on the recovery of full-weight-bearing stepping in the adult spinal cat. exp neurol 1986; 92: 421-35. 9. wernig a, nanassy a, muller s. laufband (treadmill) therapy in incomplete paraplegia and tetraplegia. j neurotrauma 1999; 16: 7197-26. table i. strength (torque n.m) of the quadricep and hamstring muscles of the right and left leg before (4.5 months after injury) and after 1 year of training (16.5 months after injury) peak extension torque (n.m) peak flexion torque (n.m) right leg left leg right leg left leg before after before after before after before after 17.4 23.9 16.9 23.8 18.7 48.8 16.6 41.5 table ii. progression of therapy regimen of patient with c6 sci for 1 year (i.e. from 5 months to 17 months) postoperatively mode 0 3 months 3 6 months 6 12 months times per week exercise routine locomotor training 4 bouts of 4 minutes 2 bouts of 8 minutes 2 bouts of 10 minutes 5 overland walking after 4 weeks used walking after 4 months used parallel 6 9 months walked on 5 frame for 1 bout of 8 metres bars for 4 bouts of 6 metres modified crutches for 8 metres continuously 9 12 months walked on smaller modified crutches for 8 metres continuously other exercises crawling, upper body cycling, same same 5 weight training, core stability and mat exercises other therapies reflexology 1 x week acupuncture 1 x week podiatry 1 x week 1 x week massage 1 x week 1 x week hydrotherapy 1 x week 1 x week transcutaneous rectus abdominus, electro-muscular rectus femoris: 3x half hour stimulation per day 92 sajsm vol 20 no. 3 2008 pg91-92.indd 92 10/17/08 12:57:30 pm original research introduction chronic diseases of lifestyle (cdl) are on the increase in south africa as in the rest of the world. this increase in the number of communicable and non-communicable diseases has labelled south africa as a country with a ‘double burden of disease. 1 cdl are a group of diseases that share similar risk factors as a result of exposure, over many decades, to unhealthy diets, smoking and lack of exercise and possibly stress. 2 these risk factors further include inter alia high blood pressure, high blood cholesterol, diabetes and obesity. these risk factors present in various disease processes such as stroke, heart attacks, certain cancers, chronic bronchitis and many others that culminate in high mortality and morbidity rates. 3 research has indicated that regular physical activity can positively address all above-mentioned pathological conditions and thereby reduce the mortality and morbidity rates in populations. 3 biokinetics has drawn on and implemented this body of evidence to prescribe scientifically based exercise programmes to prevent and manage non-communicable diseases in south africa. in developed countries physical inactivity is estimated to cause 6.0% of all deaths for men and 6.7% for women. 4 a study investigating the cost-effectiveness of health care-based interventions aimed at improving physical activity found evidence for cost effectiveness in groups with high risk, such as older persons and persons with heart failure. 5 in south africa, biokinetics has been practised for the last 25 years after the scope of practice was published in the government gazette. 6 although the road to obtaining recognition was very difficult, 7 the profession has continued growing, with 12 training institutions training about 150 students every year. more than 1 000 biokineticists have completed their training during the last 25 years, with the current register of the board of health care funders (bhf) reporting 799 active practice numbers for 2009. 8 the scope of practice for biokinetics deals with the prescription of scientifically based exercise for preventing and treating cdl as well as for finalphase rehabilitation of orthopaedic injuries. 9 biokineticists usually form part of a multidisciplinary team in the treatment of chronic diseases and orthopaedic injuries together with medical practitioners, physicians, physiotherapists and dieticians. in the south african health care sector, however, biokineticists only form part of the multidisciplinary team in the private health care sector. research indicates that this formal private health sector is a large, well-developed, resource-intensive and highly specialised sector that provids health insurance coverage to some 7 million people. 10 the other estimated 40 million south africans make use of either the public health care system or traditional healers, or pay out of their pockets for private health care services. as biokineticists are not employed in the public health sector, except in the national the potential market demand for biokinetics in the private health care sector of south africa correspondence: professor s j moss phasrec in the school of biokinetics, recreation and sport science north-west university (potchefstroom campus) potchefstroom, 2520 tel: 018 2991821 fax: 018 285 6028 e-mail: hanlie.moss@nwu.ac.za sarah j moss (phd)1 martie s lubbe (phd)2 1 niche area for physical activity sport and recreation (phasrec) in the school of biokinetics, recreation and sport science, north-west university (potchefstroom campus), potchefstroom 2 niche area for medicine use in south africa (musa) in the school of pharmacy, north-west university, potchefstroom abstract objective: biokinetics, a profession registered with the health professions council of south africa (hpcsa), address inter alia chronic diseases of lifestyle (cdl) with exercise as treatment modality. the purpose of this investigation is to determine the potential market demand for biokinetic services in the private health care sector of south africa. methods: data from a pharmaceutical benefit management system (pbm) were analysed to determine the prevalence of chronic diseases in the private health care sector for 2007. telephonic interviews on a sub-sample of 50 biokineticists revealed the average number of patients that can be treated monthly per biokineticist. the number of biokineticists with active practice numbers was obtained from the board of health care funders (bhf). results: the results indicate that 47% (747 199/1 600 000) of the patients managed by the pbm are treated with medication for one or more cdl. non-steroid anti-inflammatory medication (21%), medication for cardiovascular diseases (13%) and bronchodilators (11%) had the highest prevalence. the sub-sample of biokineticists indicated that one biokineticist can treat an average of 100 patients per month. the potential market demand calculated from the above numbers indicated that 7 472 biokineticists are needed in the private health care sector, while only 625 active practice numbers were registered with the bhf in 2007. conclusion: in conclusion, it is estimated that only 7.6% of patients with cdl can potentially be treated by the current number of registered biokineticists. therefore an enormous market potential for biokinetics exists in the private health care sector of south africa. 14 sajsm vol 23 no. 1 2011 sajsm vol 23 no. 1 2011 15 defence force, people making use of the public health care system are not exposed to biokinetic intervention. although other health disciplines are attracted away from the public health sector with large financial and personal incentives, 10 this is not the case with biokinetics. this lack of job opportunities in the public health sector has forced biokineticists to become entrepreneurs by starting private practices. these practices are solo practitioners, associations or partnerships with other biokineticists or other health practitioners. this is, however, not as straightforward as other entrepreneurial ventures. strict ethical guidelines set by the hpcsa to guide the profession and protect the public against exploitation hamper biokineticists to do marketing to the same extent as unregistered/unregulated professions. 9 in order to start any new venture, determining the market potential for the product is extremely important. as the purpose of all businesses is to create wealth, the product, price, packaging and place of sale should be thoroughly investigated. 11 health professionals are unfortunately seldom trained in business principles. this lack of business skills often results in the failure of biokinetic practices to be sustainable over a long period. this may create the perception that the potential market demand is too small to sustain the number of biokineticists trained annually. in the history of biokinetics in south africa no studies have investigated the potential market demand for biokinetics, based on the services delivered by the profession to the public. the purpose of this study was to determine the potential market demand for biokinetics in the private health care sector of south africa. the results obtained from this investigation will shed some light on the potential number of biokineticists that could be trained per year, given no restrictions from the training institutions with regard to lecturing staff. research methodology data collection the study was an observational study to determine the potential market need for biokinetics. in order to understand the method ology, it is important to define the market. according to wood 12 the market potential is all the customers who may be interested in the service that is presented. it is, however, important to remember that some customers in this potential market are unaware of the product, some may not have access to it, some may not be able to use it and some may not be able to afford it. the potential market represents the maximum number of customers who might buy the product – but not the number who will realistically buy it. 13 the approach that was followed (fig. 1) was to determine the number of persons in the identified segment (persons with a chronic disease of lifestyle) that potentially require the service and the number of potential service delivery points (practising biokineticists) matching each other. this was performed within the south african private health care framework. for the purpose of this study, the market segment that was identified to base the potential market demand on was that of persons with cdl and orthopaedic abnormalities. although the scope of practice for biokineticists 9 includes the pathogenic and the fortogenic (health promotion) paradigms, it was decided to focus only on the pathogenic paradigm for the purpose of this study. because secondary data were used for the analyses, it was important to ensure that they are timely, unbiased, legitimate, reliable and qualified. 12 in order to comply with these criteria, it was decided to make use of timely (2007), unbiased and reliable information from a private sector medicine claims database. the data are reliable as the database is created online in real time as patients collect their prescriptions. the geographical area, according to postal code of the consultation room of the prescriber, was also captured. the medicine claims data were from a pharmacy benefit management company (pbm). the pbm company administered medicine claims data of members of medical schemes from almost all community pharmacies and 98% of the dispensing doctors. for security, ethical, patient and provider identification reasons, pbm company was not identified by name. prevalence of chronic diseases of lifestyle the niche area: medicine use in south africa (musa) has the rights to use the medicine claims database of the specific pbm for research purposes. ethical clearance was obtained from the ethics committee of the north-west university (project number: nwu-0046-08-s5). this system is a fully integrated management system for more than 42 medical scheme clients administered by 17 different health care administrators. in 2007, 1.6 million south africans benefited from this system. all medicines prescribed for chronic diseases were classified according to the coding system in the monthly index of medical specialties (mims) classification system, which classifies medicine according to its pharmacological action. 14 a further classification of medicine information was performed with regard to the place (consultation room) of prescriber (province, district council, municipality and main place level). the statistical analysis system ® , sas 9.1 ®15 programme was used to group all prescribed practice addresses according to province, district council, municipality and main place level. this allowed the researchers to identify the number of diseases treated with medication and the number of patients who received chronic medicine in different geographical areas in south africa. from the database all chronic conditions where exercise is considered an appropriate treatment modality and that is addressed by biokineticists in their scope of practice as announced in the government gazette 6 in 1983, were extracted to determine the national and provincial prevalence of the following chronic diseases in south africa: hypertension, diabetes, obesity, dyslipidaemias, cardiovascular diseases, osteoporosis, depression and chronic obstructive pulmonary diseases (copd). biokineticist to patient/client ratio in order to determine the potential market for biokinetics in the private health care sector, the ratio of biokineticist to patient or client fig. 1. a schematic presentation of the research methodological approach. pbm dataset biokinetics prevalence distribution chronic disease hpcsa & basa dataset biokineticists bio/patient ratio distribution number of biokineticists ? = number of biokineticists chronic disease of lifestyle fig. 1. a schematic presentation of the research methodological approach. 16 sajsm vol 23 no. 1 2011 was also determined by means of a telephone survey. biokinetics practice owners registered with the biokinetics association of south africa (basa) website were asked to indicate the average number of active clients/patients treated at their facility monthly, the number of biokineticists and intern-biokineticists working in the practice. the ratio of biokineticist to patient/client was determined from this information. statistical analysis descriptive statistics with frequency tables, mean ± standard deviation and graphs were performed in order to determine the market potential for biokinetics in the private health sector. mathematical calculations were performed to calculate the potential market need for biokineticists. results the purpose of this study is to determine the potential market demand in the broad term for biokinetics in the private health care sector, specifically with reference to the pathogenic paradigm. in order to determine this potential demand the results will be presented by determining the prevalence of cdl, reporting on the physical activity levels of the population and the available biokineticists and practices that address the cdl with exercise. the prevalence of cdl as represented by chronic medication use from a medicine claims database of a pbm company indicated that 911 212 chronic diseases were treated within the 1.6 million subscribers (table i). the average age of the persons taking chronic medication for diseases related to cdl was 36.8 ± 21.8 years. the average age was calculated according to the age at the first prescription date. the females were slightly older than the males (m=35.4±21.9 years; f=37.9±21.8 years). totals in the table do not add up, as a few claims could not be placed according to geographical region (provinces) but are included in the calculations. the results of table i indicate that the prevalence of cdl is 66% in the specific pbm database for 2007. it is however known that one person could be diagnosed and treated for more than one disease, as is often the case for persons with diabetes mellitus. the calculation of the number of patients represented by the prevalence of cdl in the pbm (table ii) indicates that 47% of persons registered with the pbm are treated for cdl and receiving medication for the cdl. the prevalence of persons with cdl is the highest in the gauteng province at 19%, with the lowest prevalence the northern cape at 1%. when the results form table ii are further divided by age and ratio of female/male it shows that except for gout, the ratio of women obtaining chronic medication is higher than for men. the average age of the patients also indicate that lung disease is present mainly in the younger population, with the average age of persons treated with bronchodilators at 33.0±23.2 years and those with asthma table i. the prevalence of diseases related to chronic diseases of lifestyle receiving medication in the private health care sector based on a pbm company database in 2007 for the different provinces in south africa cdl eastern cape free state gauteng kwazulunatal limpopo mpumalanga northwest northern cape western cape total anti depressants 9 080 8 149 50 763 16 106 6 854 5 650 7 692 2 314 14 993 122 026 epilepsy 1 547 1 604 13 583 5 091 958 1 081 1 476 324 2 717 28 481 parkinsonism 291 268 1 807 593 145 154 235 60 557 4 123 nsaid 23 214 16 022 137 497 48 487 23 156 19 820 23 304 5 130 33 836 332 173 gout 1 333 994 7 708 2 113 913 1 150 999 233 2 196 17 681 osteoporosis 855 607 4 815 1 670 211 292 429 100 1 851 10 872 cvd 210 248 inotropic agents 507 495 2 384 1 028 286 259 310 131 925 6 345 arrhythmias 258 478 2 155 610 83 157 210 66 735 4 774 hypertension 11 570 9 249 66 102 22 151 6 365 6 945 8 467 2 455 23 559 157 354 angina 4 553 3 012 19 081 7 236 2 613 2 415 2 869 10 704 7 588 50 587 vasodilator 50 104 782 97 54 69 142 32 107 1 444 vasoconstrictors 233 270 2 746 514 156 303 386 89 442 5 138 hyperlipidaemia 6 393 4 166 36 455 10 509 1 986 2 891 3 519 875 14 133 81 204 bronchodilators 12 471 7 639 27 495 11 095 10 548 12 764 2 739 21 642 175 277 asthma 2 478 2 533 19 964 6 463 3 479 1 959 3 083 508 4 805 45 367 diabetes 3 388 2 335 19 638 7 981 2 557 2 129 2 586 693 6 010 47 459 total 76 543 45 905 403 129 135 009 54 314 45 662 46 683 11 029 92 774 911 212 cdl = chronic diseases of lifestyle; nsaid = non-steroid anti-inflammatory drugs; cvd = cardiovascular disease. sajsm vol 23 no. 1 2011 17 medication 32.6±25.3 years. the average age of people obtaining medication for cardiovascular diseases is 60 70 years. non-steroid anti-inflammatory medication (nsaid) is mostly prescribed to persons around the age of 45 years. this may be due to the onset of arthritis and joint and muscle pain from previous injuries. the calculation from fig. 2 indicates that from 1.6 million persons, 747 199 persons are on medication for a cdl that could be treated through exercise intervention such as presented by biokineticists. this is further divided into 316 894 persons suffering from a single disease and the rest treated for more than one disease within the cdl. the prevalence of participants on anti-inflammatory medication is the highest (21%), followed by patients who received medication for cardiovascular diseases (13%) and then patients on bronchodilators (11%) and medication for hypertension (10%). physical inactivity profiles of south africans as biokineticists address cdl with exercise as treatment, it is also important to report on the current levels of physical inactivity as it is a risk factor for cdl. 3 secondary data reported in the south african health review 10 compared the levels of inactivity reported in the general population with those reported in a corporate survey (table iii). the results indicate that about 50% of the general population does not participate in levels of physical activity that would reduce or manage cdl. current biokinetic practices in order to determine the market potential, the current number of biokineticists who render this service had to be determined. the number of practising biokineticists according to the basa website, which is an optional place to register and not compulsory (table iv), indicates 284 biokinetic practices. seventy-one of the 284 practices are accredited to employ biokinetic interns (students in training who have to complete a final year of practical training before final registration with the hpcsa can be obtained). these practices may employ more than one biokineticist and a maximum of two interns per registered biokineticist. 9 data obtained from the bhf, 8 the management system for practice numbers that enables biokineticists and patients to claim from medical insurance, indicate 625 biokineticists with active practice numbers who were also registered with the hpcsa in 2007. the distribution of these practices within south africa (table iv) indicates that the majority of the practices are in the gauteng province (130), with the second most in the western cape (63). this means that 46% of biokineticists are practising in and around gauteng, while about 22% of the total pool of practising biokineticists is active in the western cape. this leaves about 32% of the biokineticists in the rest of south africa. ratio of biokineticist to patient/client a telephonic interview with 50 randomly selected available biokineticists indicated that each biokineticist could manage about 100 1 fig 2. the prevalence (%) of disease in participants on the pbm database taking medication for the different chronic diseases of lifestyle. (nsaid = non-steroid anti-inflammatory drugs; cvd = cardiovascular disease                            fig 2. the prevalence (%) of disease in participants on the pbm database taking medication for the different chronic diseases of lifestyle. (nsaid = non-steroid anti-inflammatory drugs; cvd = cardiovascular disease.) table ii. prevalence of cdl according to the number of persons diagnosed and treated with medication for each of the provinces and in relation to the estimated population provinces estimated population persons with cdl % of the estimated population eastern cape 6 906 200 § 46 503 2.9 free state 2 965 600 § 33 110 2.1 gauteng 9 688 100 § 300 659 18.8 kwazulu-natal 10 014 500 § 112 948 7.1 limpopo 5 402 900 § 47 221 2.9 mpumalanga 3 536 300 § 42 221 2.6 north-west 3 394 200 § 49 895 3.1 northern cape 1 102 200 § 11 271 0.7 western cape 4 839 800 § 100 343 6.3 not indicated 3 028 0.2 total 47 849 800 § 747 199 46.7 § total mid-year population estimates, 2007. 16 table iii. a summary of the prevalence (%) of physical inactivity reported in different surveys surveys total (%) males (%) females (%) 51-country survey 17 46.2 44.7 47.6 youth risk behaviour 18 36.8 30.5 43 corporate survey 19 69 62 75 sadhs 20 46 43 49 world health survey 21 46 43 49 sadhs = south african demographic and health survey. 18 sajsm vol 23 no. 1 2011 (range 40 160) patients per month depending on the type of practice and the business strategy followed. there was an average of 2 biokineticists working in each practice. if every biokineticist managed 100 clients in south africa from the specific pbm, where 747 199 clients are treated for cdl, then 7 438 biokineticists will be required in south africa. table iv indicates the current number of practising biokineticists with regard to each province together with the market potential based on the prevalence of chronic disease as indicated by the pbm system. discussion cdl are a reality in south africa, a country with a double burden of disease that is created between cdl, also known as non-communicable diseases, and the infectious diseases such as hiv/aids and tuberculosis, also known as communicable diseases. the results of this study indicate that the prevalence of the cdl in this pbm system is 56% and represent 47% patients. the major three conditions represent nearly a third of all the total medicine expenditure managed by this studied pbm. this is much higher than the reported 37% of deaths attributed to cdl. 18 considering that most of the surveys report on data that were obtained either during 1998 20 (sadhs) or until 2005, 2 it is therefore possible that the prevalence of cdl has increased substantially since the last survey. although the percentages are not very high, the corresponding numbers of persons who require treatment are substantial. if these percentages of prevalence for the various cdls are extrapolated to the general population, estimated to be 47 498 000 16 (statssa, 2009) at june 2007, it could mean that about 26 795 888 people in south africa are diseased by one of the cdls. steyn et al. 2 report that about 6 million people are living with hypertension, 4 million with diabetes and about 4 million have hyperlipidaemia. steyn et al. 2 also mention that about 56% of the population has at least one of these risk factors. the prevalence of cdl as found in this investigation based on the prescription of medication, observed comparable prevalence for hypertension and diabetes as reported by puoane et al. 23 studies investigating the cost of managing cdl have highlighted the burden of cdl on an economy. 23,24 when interpreting the data on cdl from a biokineticist’s point of view, it is important to also consider the inactivity patterns in south africa. the results indicate that females are more inactive than males, with people in the corporate sector reporting inactivity levels of close to 70% in the total for males and females. 10 this is a daunting number of physically inactive persons who are often also exposed to high levels of stress in the work environment. these high levels of physical inactivity indicate that there is a huge potential for the management of chronic diseases with exercise and physical activity interventions, as the majority of the population are currently not participating in the required amount of activity as prescribed by the acsm 3 to achieve health outcomes. the results of the number of biokineticists registered with the hpcsa that also have active practice numbers indicate that the approximately 625 biokineticists are most likely accommodated within the 284 biokinetics practices in south africa. these are crude delineations as it is impossible to obtain the exact number of biokineticists who are actively earning a living as biokineticists. the reason is that persons on the register of the hpcsa continue to pay registration fees annually to ensure they stay on the role, even if they are not practising, in order to keep their registration. the reason for this behaviour is that it is difficult to obtain registration again once you have been deregistered and have not practised for a number of years. another reason for inaccurate numbers on the basa website is the fact that it is optional to register practices on the website. in spite of the inaccurate numbers, the data described are still the most accurate available that were used in the analysis and assumptions made. the distribution of the biokinetics practices simulate the areas of high income in south africa, with the most practices being in the gauteng area and the least practices in the northern cape, which has the lowest income per capita. 16 the population density in gauteng is also higher than in the northern cape, resulting in shorter travelling distances between home and biokinetic practices. the analyses of the number of patients/clients that a biokineticist is able to treat per month indicated an average of 100 persons with a range of between 40 and 160. there was an average of 2 biokineticists working per accredited practice. in order to calculate the potential market demand for biokinetics, the potential number of persons taking medication for cdl according to the analysed pbm system was divided by 100 to determine the number of potential biokineticists needed. this calculation indicated that about 7 438 biokineticists are needed. if an average of two persons work together, that means that about 3 719 practices are potentially needed. the current number of biokinetic practices is therefore calculated to be rendering a service to only 8% of the potential market. as these are pure calculations to determine the market potential, it is necessary to take into account the factors that may hamper people from visiting a biokineticist for exercise as treatment of a cdl. when calculating a market potential, the broadest market is first determined, 12 as was done with this study. it is important to remember that these results are a crude indication of the potential market demand for biokinetics in the private health care sector. this study also only focused on the pathogenic paradigm, and not the fortogenic (health promotion) paradigm, where biokinetic intervention addresses the prevention of cdl. the section of the market that has the income to afford the service and has access to the product should be determined. important factors that can influence the behaviour of the potential consumers will include gender, level of education, age, ethnic background and the perceived value for the client/patient, table iv. the relationship between the current number of practising biokineticists and the potential market need for the different provinces province current number of practices (n) market need for biokineticists* (n) eastern cape 19 465 free state 11 331 gauteng 130 3 006 kwazulu-natal 33 1 129 limpopo 5 472 mpumalanga 9 422 north-west province 11 498 northern cape 3 112 western cape 63 1 003 total 284 7 438 § *based on 100 patients/biokineticist. § numbers differ due to some claims not being linked to original place of prescribing of medication. sajsm vol 23 no. 1 2011 19 various social connections and personal elements, of which lifestyle would be the most prominent together with motivation. a study investigating the factors that influence the demand for health care in south africa using a multinomial logit estimation, found that there are three categories of factors that influence the demand. these factors are: (i) demographic and location variables (e.g. income, race and location); (ii) characteristics of the care provided (e.g. cost and distance from the respondent); and (iii) characteristics of the illness (such as severity). 25 this study also found that an increase in income indicated a decrease in the use of primary health care. where income was above r2 785 per month, primary health care was only utilised in less than 5% of the respondents. 25 these results give an indication of the income group that can be expected to seek treatment for cdl as offered by biokinetics. the limitations of this study were that the numbers on which the calculations are based are relative, although currently the most accurate available. the calculations from the pbm are also based on the prevalence of the 2007 data, as the classification of the 2008 data is not available. the number of biokineticists is also a crude number as accurate numbers are difficult to obtain. registered biokineticists often become pharmaceutical representatives to earn a larger income while also learning business and marketing skills before returning to the profession. conclusions the conclusion that can be drawn from this study is that there is a large potential market for biokinetics in the private health care sector of south africa. currently only an estimated 8% of the potential market is addressed by biokinetics with exercise as a treatment modality. this is only the calculation for the pathogenic paradigm. it therefore seems that the number of biokineticists trained annually could be increased to address the shortage in the market. however, an investigation is recommended to determine the factors that may prevent the large potential market demand from realising. references 1. vorster hh, kruger a. chronic diseases of lifestyle in south africa: the role of public health nutrition in the promotion of health, and prevention and treatment of disease. s afr j diab vasc dis 2006;3(4):179-181. 2. steyn k, fourie j, temple n, eds. chronic diseases of lifestyle in south africa: 1995-2005. mrc technical report. cape town: south african medical research council, 2006:1266. 3. thompson wr, ed. acsm’s guidelines for exercise testing and prescription, 8th ed. philadelphia: lippincott williams & wilkins, 2009:152-206. 4. world health organization. world health report 2002. geneva: who. 5. hagberg la, lindholm l. cost-effectiveness of healthcare-based interventions aimed at improving physical activity. scand j public health 2006;34:641-653. 6. the south african medical and dental council rules for the registration of medical scientists (notice 673, 1983). government gazette, 1983;8879:19. 7. strydom gl. biokinetics: the development of a health profession from physical education – historic perspective. sajr sper 2005;27(2):113-128. 8. board of health care funders. www.bhfglobal.com. 2009 (accessed 10 september 2009). 9. health professions council of south africa (hpcsa). www.hpcsa.co.za 2009. (accessed 30 august 2009). 10. harrison s, bhana r, ntuli a, eds. south african health review. durban: health systems trust, 2007. 11. kotler p, armstrong g. principles of marketing. 12th ed. upper saddle river, new jersey: pearson: prentice hall, 2008. 12. wood mb. marketing planning: principles into practice. harlow, england: prentice hall, 2004. 13. roger jb. market-based management: strategies for growing customer value and profitability, 2nd ed. upper saddle river, nj: prentice hall, 2000:59-62. 14. snyman jr, ed. mims monthly index of medical specialities. mims: pretoria. 2009. 15. sas institute inc., 2003. 16. statistics south africa. www.statssa.gov.za. 2008 (accessed 9 september 2009). 17. guthold r, ono t, kathleen l, strong kl, chatterji s, morabia a. worldwide variability in physical inactivity: a 51-country survey. am j prev med 2008;34(6):486-494. 18. reddy sp, panday s, swart d, et al. umthenthe uhlaba usamila – the south african youth at risk behaviour survey 2002. cape town: south african medical research council. 19. kolbe-alexander tl, buckmaster c, nossel c. chronic disease risk factors, healthy days and medicine claims in south africa employees presenting for health risk screening. bmc public health 2008;8(228):1-11. 20. department of health, medical research council. the south african demographic health survey. pretoria: department of health, 2002. 21. world health organization. preliminary results of the world health survey 2002-2003, international physical activity data, south african results. geneva: who, 2005. 22. puoane t, tsolekile l, sanders d, parker w. chronic non-communicable diseases. in: barron p, roma-reardon j, eds. south african health review. durban: health systems trust, 2008. 23. kouris-blazos a, wahlqvist m. health economics of weight management: evidence and cost. asia pac j clin nutr 2007;16(suppl 1):329-338. 24. ruchlin hs, dasbach ej. an economic overview of chronic obstructive pulmonary disease. pharmacoeconomics 2001;19(6):623-642. 25. havemann r, van der berg s. the demand for health care in south africa. j stud econ econometrics 2003;27(3):1-27. original research 106 sajsm vol 23 no. 4 2011 introduction body self-image is a psychological construct which has gained increasing attention in current years, and researchers 1,2 reported that active groups have a better concept of their bodies and body image than sedentary groups. with the extensive growth of the media and technology into almost every aspect of our lives, the human body is portrayed, photographed, pictured and ultimately adored or abhorred more than ever, resulting in increasing statistics of body dysmorphia and obsessions with appearance, weight, fitness and health. 1 the primary questions posited in this research study were: what happens to the body self-image when women exercise, specifically in terms of the cognitive, perceptual, affective and attitudinal aspects of their body self-image. relationship between exercise and self-image a growing number of controlled studies have identified the positive effects of exercise on general psychological well-being in ageing women. 3,4 in a wide-ranging literature review, mcauley 5 has considered the relation between exercise and both positive and negative psychological health. in line with other review articles, mcauley 5 reported a positive relationship between exercise and self-esteem, self-efficacy, psychological well-being, and cognitive functioning, and a negative relationship between exercise and anxiety, stress, and depression. such studies reinforce the notion that exercise has significant psychological health benefits for people who exercise regularly. the psychological benefits of exercise extend to positive changes in body self-image for women that occurred following exercise interventions. 1,6,7 such changes can be due to physiological processes in which exercise increases concentrations of the brain’s neurotransmitters by stimulating the sympathetic nervous system. 8 further research has shown that exercise is one of the most effective means of improving body self-image. 9,10 there is widespread support for a positive and lasting relationship between participation in regular exercise and various indices of mental health, and several consensus documents and reviews have been published in this field. 11,12 the evidence for psychological benefits, although impressive for mentally healthy individuals, is even stronger for psychiatric populations. 13 a number of studies have demonstrated a positive relationship between exercise and mental health in alcoholics, 14 people with schizophrenia 15 and those with clinical depression. 16 despite the growing body of evidence supporting the relationship between exercise and mental health, organisations have been reluctant to endorse the use of exercise in treating mental illness. furthermore, exercise has not been widely adopted by clinical psychologists and psychiatrists as a viable adjunctive intervention strategy for improving the mental health of patients. a recent overview of depression and its treatment in the uk, for example, made no mention of the value of exercise. 17 similarly, biddle et al. 11 reported that exercise as an intervention was not considered appropriate or of any incidental value by clinical psychologists. it appears that much work has to be done to convince those who deliver mental health services to focus on the relationship between mind and body and to look more positively at the role of exercise as a treatment in mental health issues. 16 this paper therefore explores the potential value of exercise as an adjunctive treatment in improving body self-image in a ‘healthy’ population of women in middle adulthood, who have their own and unique challenges. challenges confronting women in middle adulthood the developmental stage of middle adulthood occurs between the ages of 40 and 65. 18,19 women in middle adulthood are confronted with many psychological changes, 20 midlife transitions, 19 and abstract objectives. this empirical study investigated the effect of a moderate aerobic exercise programme on the body self-image of a sample of women (n=49) in middle adulthood with a mean age of 54.2 years. methods. the participants were randomly assigned to an experimental group (n=24) and a control group (n=25). the experimental group participated in a (guided) moderate aerobics programme over six weeks, while the control group participated in a sedentary (guided) meditation programme. the participants in both groups were assessed for body self-image using the nine factors defined in the body self-image questionnaire (bsiq) of rowe (2000). the bsiq comprises both perceptual-cognitive and affective-attitudinal factors. results. the results indicated that there was an overall positive shift in the perceptual-cognitive factors of the body self-image in the exercise group, namely for overall appearance evaluation, health fitness evaluation and fatness evaluation. although no significant shifts were found in all the affective-attitudinal factors of the participants, there was a significant change in the negative affect of the participants. conclusion. the results suggest that such a programme has a positive influence on the way these women think and feel about their bodies. no significant changes were found in the body selfimage of the control group. these findings suggest the positive effect of a (guided) aerobic exercise programme in improving the body self-image of women in middle adulthood. andrea k daniels (ma (psychology)) rudolph l van niekerk (d lit et phil (psychology)) department of psychology, university of johannesburg correspondence to: leon van niekerk (leonvn@uj.ac.za) the influence of a moderate aerobics programme on the body self-image of women in middle adulthood sajsm vol 23 no. 4 2011 107 physiological changes associated with signs of ageing, 21 resulting in a loss of muscle mass, muscle strength and muscle fibres. 22 women in middle adulthood are therefore at risk of internalising negative mental representations of their body self-image. mciza 23 found that differences in body image among south african women are highly driven by cultural norms, urbanisation and socio-economic status. many south african women, because of societal pressures, are at risk of suffering from a loss of self-esteem. 24 south africa, in its current climate of socio-economic emergence and transformation, engenders many challenges and stressors upon its divergent population. these stressors are seen to impact most severely on women and children. according to pillay and kriel 25 who conducted a study on south african women seeking psychological interventions, over one-third had relationship problems, 21% had depression, and 14% presented with suicidal behaviour. furthermore, nearly half the women reported significant financial problems. of the 174 married (or cohabiting) women, 95% experienced relationship problems, 57% reported substance-abusing partners, and 48% reported violent partners. clinician estimates revealed notably low self-esteem in 65% of the women. not least susceptible to these stressors are south african women in the stage of middle adulthood who, in a persistently patriarchal climate, form a group that is both largely under represented and unsupported, with minimal access to resources such as health facilities, support groups and psychological interventions. methods the specific objectives of this study were to determine if a professionally guided, moderate aerobics programme would have an impact on the body self-image of a group of sedentary south african women in the phase of middle adulthood. forthcoming from this aim, the following research questions were constructed: ● how does a moderate aerobics programme (of movement) change the body self-image of women in middle adulthood? ● how does a (sedentary) programme of guided meditation change the body self-image of women in middle adulthood? ● does a moderate aerobics programme change the body image of sedentary women in the phase of middle adulthood more than a programme of sedentary guided meditation? this study therefore aimed to examine the body self-image constructs with a pre-test post-test experimental design with a control group. a programme of (guided) moderate aerobics was applied to the experimental group (n=24), while a programme of sedentary guided meditation was applied to a control group (n=25) on a sample of 49 (n=49) women in the phase of middle adulthood. the participants in both groups were assessed for body selfimage using the nine sub-scales defined in the body self-image questionnaire (bsiq). 26 the bsiq comprises both perceptualcognitive and affective-attitudinal items, which are intended to elicit responses pertaining to these different constructs. moderate to high internal consistency (cronbach’s alpha) was found on all the subscales, ranging from 0.59 to 0.90. instruments the constructs of body self-image were measured using the 51-item bsiq. 26 the bsiq is a self-administered questionnaire, with questions that elicit answers on a 5-point likert scale, with 1 (not at all true of myself) to 5 (completely true of myself). apart from reversescored items, the higher the score, the more positive the evaluations and perceptions of body self-image. the bsiq is currently the most widely used measure of global body self-image within health psychology. it has received extensive psychometric scrutiny (i.e. confirmatory factor analysis) and has been validated on several samples of normal and divergent groups, including individuals with eating disorders and body dimorphic disturbances. 26 furthermore, the bsiq has been proven to be a reliable, valid measure and has shown an internal consistency of 0.87. 9 internal consistency (cronbach’s alpha) for the nine subscales have ranged from α=0.78 (social dependence) to 0.94 (fatness evaluation). 26 the cognitive-perceptual constructs of body self-image is conceptualised and measured in the bsiq 26 on the following subscales: ● overall appearance evaluation. this factor includes self representations such as ‘i perceive my overall appearance to be ugly/ fat/scruffy etc.’, based on objective self-evaluations such as one’s attire, grooming, actual weight, and may extend as far as ‘i perceive this because i can no longer fit into my jeans’. ● fatness evaluation. this dimension of body self-image would produce statements such as ‘my buttocks are fat!’ again, this factor is based on objective self-evaluations of fatness which the individual perceives as a consequence of weighing more, of not being able to fit into one’s jeans. ● health fitness evaluation. this dimension of body self-image would produce statements such as ‘i feel fit and healthy!’ again, this factor is based on objective self-evaluations of fitness and health which the individual perceives as a consequence of working out more frequently, eating better, etc. the affective-attitudinal constructs of body self-image is conceptualised and measured in the following sub-scales: ● health fitness influence. this factor includes self-representations such as ‘i feel that my fitness levels impact on my selfconfidence and well-being’, based on subjective feelings and attitudes. ● attention to grooming. this factor of body self-image would produce statements such as ‘i like to be seen in smart clothes’, which represents the individuals’ attitudes and feelings about their presentation to others. ● negative affect. this factor of body self-image would produce statements such as ‘i feel ashamed and depressed about my weight’. again, this factor is based on subjective attitudes and feelings. ● investment in ideals. this factor of body self-image would produce statements such as ‘i like people to think i am a kind person’. again, this factor is based on subjective attitudes and feelings. ● height dissatisfaction. this factor of body self-image would produce statements such as ‘i think i am too short’. again, this factor is based on subjective attitudes and feelings. sample sixty (n=60) normal weight (ascertained by means of body mass index (bmi)), sedentary females in middle adulthood (between the ages of 45 and 60), with no history of low-impact aerobic exercise, were asked to volunteer for participation in the study. invitations to participate were given at various women support groups and training centres in the local community by word of mouth. inclusion criteria were ascertained through the use of a biographical questionnaire and a physical attributes questionnaire. after the exclusion of women who did not meet the inclusion criteria, a sample of 49 women was obtained and randomly assigned to the experiment (n=24) and control (n=25) groups. a total of nine participants had to exit from the study due to work constraints, travel arrangements and family responsibility. the mean age of the total sample was (54.2±6.98) years, with the mean age of (53.6±7.28) for the experiment group and (55.9±6.79) for the control group. 108 sajsm vol 23 no. 4 2011 research design and intervention participants were randomly assigned to one of two 6-week programmes. this study utilised a two-group pre-test post-test experimental design where a moderate aerobics programme was administered with the experimental group, while the control group was assigned a meditation programme, rather than being told to do nothing, as a way to control for possible social interaction effects during exercise. 27 randomisation was stratified by bmi to ensure balanced weight distribution of the women in each group and internal validity of the study. data analysis (descriptive statistics and independent sample t-tests) was done to determine the extent to which the separate interventions influenced body self-image in the two groups. the experimental group participated in bi-weekly exercise session lasting for 45 minutes per session. after an adequate warmup session of 10 minutes, which included breathing, focused body work, upper body arm exercises and light cardio-exercises (such as walking forwards and backwards, lunges, stretches and knee lifts), the aerobics session started. the session lasted for 35 minutes and included exercises such as the grapevine step, marching, knee lifts, walking routines, the v-step and hamstring curls. these exercises engaged the major muscle groups and body areas where the participants expressed both fatness and fitness concerns. exercises began at approximately 40% of vo2max for 15 minutes and gradually increased to approximately 60 70% of vo2max for the remaining 25 minutes. polar heart rate monitors were used to ensure that participants did not exceed 70% of vo2max. the control group engaged in a bi-weekly (sedentary) guided meditation programmes for 45 minutes per session. each session comprised a 10-minute introduction and discussion session, followed by a 5-minute chanting and relaxation session and a 20-minute meditation session. the session was concluded with 5 minutes of breathing and 5 minutes of discussion. results the results presented in table i indicate that all participants were within the acceptable ranges of bmi, showing 40 (68%) participants being within normal range, and 20 (32%) being overweight. fatness percentage levels showed 31 (51%) participants with a slim body fat percentage and 29 (49%) within the normal range of body fat percentage. these anthropomorphic results indicated that all participants were fit enough to participate safely in the programme of moderate aerobic exercise. the results of the pre-tests and post-tests on the sub-scales of the bsiq are presented in table ii. as the study was more concerned with within-group changes rather than with between-group differences, only within-group change results are presented. even though the aerobics and meditation programmes could have had similar effects on the cognitive-perceptual and affective-attitudinal sub-scales of the bsiq, the validity of the study would not be compromised. the mean scores, standard deviations and significance of the within changes (set at p<0.01) for the experiment and control groups on the cognitive-perceptual sub-scales and affective-attitudinal sub-scales are indicated. the results presented in table ii indicate a significant difference in overall appearance evaluation (p=0.001). thompson et al. 28 also reported enhanced scores on the physical appearance state among women with low appearance evaluation in their research. the results (table ii) further indicated a significant difference in the health fitness evaluation (p=0.001) and fatness evaluation (p=0.001) of the experimental group. regular activity and improved fitness have a beneficial effect on self-esteem and body image. 10 cash and pruzinsky 29 reported a significant correlation between appearance evaluation and fitness orientation (0.542) as well as between appearance evaluation and health orientation (0.533). their findings indicated that participants who were generally more positive about their appearance place a greater importance on fitness and health. however, they also warned that these individuals may have a greater chance of suffering from body-image disturbance. these significant differences were not achieved in the control group, indicating that the 6-week moderate aerobics programme had a significant positive impact on the cognitive-perceptual aspects of the body self-image of the participants. there were no significant changes in all but one of the affective-attitudinal sub-scales. investment in ideals, factor health fitness influence (hfi), attention to grooming (ag) or height dissatisfaction (hd) had significance levels larger than p=0.01. however, for negative affect (na) there was a significant positive shift in the participant’s affect for both the experimental (p=0.001) and control group (p=0.002). these findings are in agreement with russo-neustadt et al., 8 who maintained that exercise increases concentrations of the brain’s neurotransmitters by stimulating the sympathetic nervous system. they maintain that since exercise increases brainderived neurotrophic factor (bdnf) production directly, there is a reinforcement of the serotonin-bdnf loop, indicating exercise’s significant potential as a mood enhancer. these results showed significantly improved body self-image scores for the experimental group who did 6-week moderate aerobic exercise. the experimental group experienced the greatest improvement in body self-image, specifically in the domain of perceptual-cognitive body self-image (overall appearance evaluation, health-fitness evaluation, and fatness evaluation). it seems therefore that a programme of exercise (movement) is significantly more beneficial to body self-image than a programmeme of sedentary guided meditation. table i. physical attributes of the sample body mass index body fat (%) fitness scale participants scale participants scale participants 18.5 24.9 n=40 slim n=31 61 75 (a) n=60 (normal) 68% 51% 100% 25 29.9 n=20 normal n=29 76 86 (aa) 0 (overweight) 32% 49% 30 & above 0 obese 0 (obese) sajsm vol 23 no. 4 2011 109 discussion that body self-image (on a cognitive-perceptual level) improved significantly in the exercise group. this finding supports the original research questions and is consistent with research supporting the positive outcomes of a programme of moderate aerobics with women in the phase of middle adulthood. apart from negative affect, there were no significant differences in either of the sub-scales of body self-image in the control group that did a programme of sedentary guided meditation. these findings therefore suggest a positive influence of (guided) moderate aerobics exercise on improved body selfimage. in agreement with this, various researchers 10,30,31 showed that active adults had a more positive body-image than inactive adults. it seems therefore that participation in physical activity can increase physical abilities and fitness and this, in turn, results in self-esteem improvement and positive attitude towards your body. sonstroem and morgan’s 32 self-esteem model (exem) proposed that the objective evaluation from physical capabilities may be increased by exercise. this evaluation can improve self-acceptance or self-worth without considering perceived competency. fox and corbin 33 in the development of the physical self-perception profile (pspp) showed that there are strong associations between efficacy and physical fitness. sonstroem et al. 34 also proposed that self-esteem improvement following participation in physical activity can be attributed to physical fitness improvement, meeting one’s personal goals, competency improvement, health behaviour promotion such as sufficient sleep and nutrition and confront with new social experiences as a result of activity with others. the results of this study were in agreement with other previous findings and can be applied to women in middle adulthood. tucker and maxwell, 35 for example, found the body cathexis scores of females participating in moderate exercise to be greater than those of a control group. results of the current study lend support to these findings in that the aerobic group had significantly better positive body image scores in several of the body image subscales than those in the control group. in light of the positive effect of an exercise programme on body self-image changes as opposed to that of one which is meditative and predominantly intrinsically focused, physical activity should gain more credibility as a body self-image enhancing technique. as clinical psychologists are inclined to dismiss physical activity as a possible treatment 11 of body self-image issues, this research provides evidence to suggest that an approach that excludes physical exercise as part of an intervention could be questioned. conclusion empowering people and the communities in which they live is an important aim of exercise psychology, and this exploration adds a dynamic component to ongoing dialogue within the field of exercise psychology and women within our society. a healthy body self-image is therefore clearly a prerequisite for overall positive self-regard, especially for women in the phase of middle adulthood. in this regard, this research study can be seen to be beneficial to both healthy and disordered sectors of society. further research is needed to define how the psycho-dynamic properties of (guided) exercise and exercise therapy can be utilised effectively as a tool for the treatment of a variety of psychophysiological disorders and disabilities, including psychotherapeutic, psycho-social, and physical rehabilitation. table ii. within-group changes for both the experimental and control groups pre-test pre-test scale group mean±sd sem mean±sd sem p-value cognitive-perceptual sub-scales overall appearance evaluation (oae) experiment 2.69±0.363 0.074 3.39±0.499 0.102 0.001 control 2.72±0.498 0.104 3.04±0.517 0.108 0.023 health fitness evaluation (hfe) experiment 2.39±0.302 0.062 3.27±0.617 0.126 0.001 control 2.70±.439 0.091 2.84±.451 0.094 0.019 fatness evaluation (fe) experiment 3.27±0.366 0.075 2.56±0.385 0.079 0.001 control 3.12±0.388 0.081 3.06±0.414 0.086 0.302 affective-attitudinal sub-scales investment in ideals (ii) experiment 3.39±0.373 0.076 3.34±0.487 0.099 0.095 control 3.26±0.384 0.080 3.20±0.327 0.068 0.317 health fitness influence (hfi) experiment 3.53±0.321 0.066 3.59±0.431 0.088 0.370 control 3.39±0.424 0.088 3.43±0.428 0.089 0.212 negative affect (na) experiment 2.90±0.368 0.075 2.26±0.357 0.073 0.001 control 2.89±0.579 0.125 2.57±0.490 0.102 0.002 attention to grooming (ag) experiment 3.25±0.489 0.100 3.31±0.450 0.092 0.347 control 3.39±0.482 0.100 3.50±0.452 0.094 0.059 height dissatisfaction (hd) experiment 1.74±0.511 0.104 1.71±0.409 0.083 0.516 control 2.32±0.788 0.164 2.22±0.769 0.160 0.038 sd – standard deviation; sem – standard error of the mean. 110 sajsm vol 23 no. 4 2011 references 1. cash tf. body image attitudes: evaluation, investment and affect. perceptual and motor skills 1994;78:1168-1170. 2. shaw sm. body image among adolescent women: the role of sports and physical active leisure. journal of applied recreation research 1994;16(4):349-367. 3. netz y, wu mj, becker bj, tennenbaum g. physical activity and psychological well-being in advanced age: a meta-analysis of intervention studies. psychol aging 2005;20:272-284. 4. viera pn, mata j, silva mn, et al. predictors of psychological well-being during behavioral obesity treatment in women. journal of obesity 2011:18. doi:10.1155/2011/936153 5. mcauley e. the role of efficacy cognitions in the prediction of exercise behavior. womens health issues 2003;13(4):158-166. 6. finkenberg me, dinucci j, mccune sl, chenette t, mccoy p. commitment to physical activity and anxiety about physique among college women. perceptual and motor skills 1998;87:1393-1394. 7. henry r, anshel m, michael t. effects of aerobic and circuit training on fitness and body image among women. journal of sport behavior 2006;29(4):281-304. 8. russo-neustadt aa, beard rc, huang ym, cotman cw. physical activity and antidepressant treatment potentiate the expression of specific brainderived neurotrophic factor transcripts in the rat hippocampus. neuroscience 2000;101(2):305-312. 9. baldwin mk, courneya ks. exercise and self-esteem in breast cancer survivors: an application of the exercise and self-esteem model. journal of sport and exercise psychology 1997;19:347-358. 10. davis c. body image, exercise and eating behaviors: the physical self from motivation to well-being. champaign: human kinetics, 1997:143174. 11. biddle sjh, fox k, boutcher sh. the way forward for physical activity and the promotion of psychological well-being. in: biddle sjh, fox k, boutcher sh, eds. physical activity and psychological well-being. london: routledge, 2000:154-168. 12. craft ll, landers dm. the effects of exercise on clinical depression and depression resulting from mental illness: a meta-analysis. journal of sport & exercise psychology 1998;20:339-357. 13. biddle sjh, mutrie n. psychology of physical activity: determinants, wellbeing and interventions. london: routledge, 2003:236-254. 14. donaghy me. an investigation into the effects of exercise as an adjunct to the treatment and rehabilitation of the problem drinker. phd thesis, medical faculty, glasgow university, glasgow,1997. 15. chamove a. positive short-term effects of activity on behaviour in chronic schizophrenic patients. br j clin psychol 1986;25:125-133. 16. mutrie n. the relationship between physical activity and clinically defined depression. in: biddle sjh, fox k, boutcher sh, eds. physical activity and psychological well-being. london: routledge, 2000:46-62. 17. hale as. abc of mental health: depression. j sports sci 1997;315:43. 18. lachman m. handbook of midlife development. new york: wiley, 2001. 19. levinson d. the midlife-transition: a period of adult psychosocial development. psychiatry 1977;40:99-112. 20. mroczek dk, spiro a, griffen pw, neuperd s. social influences on adult personality, self-regulation and health. in: schaie kw, carstensen l, eds. social structures, aging and self-regulation. new york: springer, 2006:69-83. 21. baron, ra, byrne d. social psychology: understanding human interaction. boston: allyn and bacon,1991. 22. hakkinen k. neuromuscular adaptation during strength training, aging, detraining and immobilization. critical reviews in physical rehab medicine 1994;6:161-198. 23. mciza z. development and validation of instruments measuring body image and body weight dissatisfaction in south african mothers and their daughters. nutrition 2005;21:34-50. 24. alipoor sa, moazami-goodarzi m, zarra-nezhad, zaheri l. analysis of the relationship between eating attitudes and body shape in female students. j appl sci 2009;10:1994-1997. 25. pillay al, kriel aj. mental health problems in women attending district-level services in south africa. journal of social science med 2006;63(3):587592. 26. rowe da, benson j, baumgartner t. development of the body self-image questionnaire. measurement in physical education and exercise science 1999;3(4):223-247. 27. portney l, watkins m. foundations of clinical research: applications to practice. new jersey: prentice hall, 2008. 28. thompson jk, coovert md, stormer sm. body image, social comparison, and eating disturbance: a covariance structure modelling investigation. int j eat disord 1999; 6:43-51. 29. cash tf, pruzinsky t. body image: a handbook of theory, research, and clinical practice. new york: guilford, 2002. 30. franzoi sl. effects of aerobic exercise on female body esteem: a multidimensional approach. paper presented at the annual convention of the american psychology, 22 26 august 1986. washington dc (web spirs, search ed 282115). 31. daley aj, parfitt g. physical self-perceptions, aerobic capacity and physical activity in male and female members of a corporate health and fitness club. perceptual and motor skills 1996;83:1075-1082. 32. sonstroem rj, morgan wp. exercise and self-esteem: rationale and model. medicine and science in sports and exercise 1989;21:329-337. 33. fox kr, corbin cb. the physical self-perception profile: development and preliminary validation. journal of sport and exercise psychology 1989;11:408-430. 34. sonstroem rj, harlow ll, josephs l. exercise and self-esteem: validity of model expansion and exercise associations. journal of sport and exercise psychology 1994;16: 29-42. 35. tucker la, maxwell k. effects of weight training on the emotional well-being and body image of females: predictors of the greatest benefit. american journal of health promotion 1992;6:338-344. introduction maximal oxygen uptake provides a highly reproducible measure of aerobic capacity only if rigid criteria for determining the attainment of vo2max are applied. 1 standard criteria for the termination of a maximal test were established by the british association of sports sciences. 2 according to these standards, the physiological and perceptual responses measured at exhaustion can be considered maximal if the increase in vo2 with increasing work rate exhibits a plateau, if heart rate (hr) is within 10 b.min -1 of the age-predicted maximum, if the respiratory ratio (rer) is greater than 1.15, if peak blood lactate (la) concentration is above 8 mmol.l -1 and if the individual is perceived to be exhausted with a rating of perceived exertion (rpe) equal to, or higher than 18. 2 if these criteria are not achieved, the vo2 value at maximum is referred to as vo2 peak. although these criteria have been used extensively, there has been controversy surrounding the validity of them to indicate maximal effort. 3 in addition to this, although there is a wealth of information comparing the vo2max values of trained and untrained individuals, there is limited information comparing whether the other maximal criteria are met similarly in groups with differing levels of training. this investigation thus sought to compare not only the vo2max values of trained versus untrained individuals, but also other maximal physiological and perceptual responses obtained during a continuous, incremented treadmill test. also, the frequency of achievement of the various vo2max criteria between the two groups of subjects was evaluated. the hypothesis proposed was that trained individuals would achieve a higher maximal oxygen uptake than their untrained counterparts. furthermore, it was proposed that the remaining maximal british association of sport sciences criteria (hr, rer, la, and rpe) as well as peak treadmill running speed and total test time would differ between the trained and untrained groups. methods eight trained and 9 untrained male subjects aged 18 25 years were recruited from a university student population. the study was approved by the ethics committee of the department of human kinetics and ergonomics, rhodes university, grahamstown. each subject provided written informed consent and basic measures were obtained (table i). all subjects were of a similar age, stature and mass, and bmi values fell within the ‘normal’, healthy range for young males. selection criteria for the trained subjects included participation in endurance training at least 3 times a week for the 3 months prior to testing and completion of at least 1 half-marathon in that time period. with regards to the untrained subjects, only individuals who reported no regular or occasional aerobic exercise (above that required for daily activities) for the 3 months prior to testing were selected. original research article impact of training status on maximal oxygen uptake criteria attainment during running abstract objectives. the aims of this study were to assess whether training status influenced maximal physiological and perceptual responses and whether certain maximal criteria were more sensitive for individuals with different levels of training. methods. males who were either trained (n=8) or untrained (n=9) underwent a maximal treadmill test to assess whether the criteria to indicate vo2 max were training-specific. results. vo2 max was significantly higher in the trained (70.0 mlo2.kg -1 .min -1 ) compared with the untrained group (54.5 mlo2. kg -1 .min -1 ). only 11% of the trained and 56% of the untrained individuals achieved a plateau in the oxygen uptake curve. peak treadmill running speed was significantly faster and total test time significantly longer in the trained group. in contrast, peak lactate, although maximal for both groups, was significantly higher in the untrained group (13.5 mmol.l -1 compared with 10.3 mmol.l -1 ). the other responses were not different between the groups. noteworthy is that none of the subjects achieved all of the criteria indicating a maximal effort. the criteria most achieved in both samples were hrmax, rpemax and lamax with the latter being the most attained in the untrained group and rpemax being mostly attained by the trained group. conclusions. the criteria used to indicate attainment of vo2 max may be limited and may differ when comparing a heterogeneous training sample. although vo2 max was significantly higher in the trained group, responses were different for o2 plateau attainment and lamax but similar for the other british association of sports sciences criteria. it may be concluded that the physiological variables coinciding with maximal effort may differ in individuals with different levels of training. correspondence: candice christie department of human kinetics and ergonomics po box 94 rhodes university grahamstown 6140 south africa tel. +27 (46) 603-8470 fax. +27 (46) 622-3803 e-mail: c.christie@ru.ac.za candice jo-anne christie (ba, hms, bsc (med)(hons), msc, phd) briar ingram lock (ba, hons) department of human kinetics and ergonomics, rhodes university, grahamstown sajsm vol 21 no. 1 2001 19 each subject performed 1 maximal test using the same protocol, the progressive speed protocol (psp). participants had to avoid extreme climates 36 hours before testing and were instructed to avoid alcohol, medication and strenuous exercise in the 24 hours prior to the test session. the progressive speed protocol, originally described by matter et al. 4 started at a speed of 12 km.h -1 which was maintained for 1 minute. 5 the speed of the treadmill was then increased by 1 km.h -1 every minute thereafter until volitional exhaustion. according to mcardle et al. 6 motivational factors play a major part in achieving maximal performance and therefore subjects received strong verbal encouragement throughout the entire test. this encouragement was consistent for all the tests and involved notifying the subjects of the amount of time left to complete each speed. expired air was continuously sampled during the test (quark b 2 , cosmed, italy) and before each test the gas meters were calibrated with a gas mixture containing 4.9% co2 with the remainder made up of a n2/o2 mixture. on arrival at the laboratory subjects were fitted with a polar sports tester heart rate monitor (polar electro, kempele, finland) and the face mask for the quark b 2 , which were both fastened securely. subjects were required to perform a 5-minute warm-up on a stationary cycle ergometer at their own chosen intensity. according to shephard, 7 a brief warm-up reduces the risk of musculoskeletal injuries and electrocardiographic abnormalities, while yielding greater vo2max values. the subjects were then instructed to carry out a stretching routine, with particular focus on the quadriceps, hamstrings and gastrocnemius muscles. when this had been completed, the mouthpiece for expired gas analysis was attached to the mask. although specific criteria have been developed by the british association of sport sciences 3 to indicate when vo2max has been achieved, test termination in this investigation was exclusively dependent on volitional fatigue. accordingly, participants had to stop the test and straddle the treadmill when they felt they had reached their maximum effort. however, as it was imperative that subjects reached maximum effort, it was explained that they needed to keep running until they felt they could no longer continue and they were verbally motivated to push to maximum and continue for as long as possible during the test. the highest vo2 recorded during any interval was recorded as the individual’s vo2 peak. heart rate was recorded continuously during the test by a sports tester heart rate monitor. maximal heart rate (hrmax) was defined as the heart rate at the time of test termination. central ratings of perceived effort were recorded every minute using the borg scale. 8 the scale grades levels of exhaustion from a rating of 6 (resting) to a rating of 20 (maximal effort). the rer was measured throughout the test and lactate (accutrend, roche diagnositics, usa) was measured and recorded via the ‘pin prick’ method from the left ring finger on termination of the test while the subject was still straddling the treadmill. statistical analysis all data were expressed as means ± standard deviation (sd). maximal physiological and perceptual values between groups were compared using a t-test for independent samples. the level of significance was set at p<0.05. results there was no significant difference in age, stature, mass and bmi between the samples (table i). table ii shows that trained subjects reached significantly higher (p<0.05) maximal oxygen uptake values (70.0 ml.kg -1 .min -1 ) than the untrained subjects (54.5 ml.kg -1 .min -1 ), demonstrating that the selection criteria with regards to training status were accurate. however, the large standard deviation in vo2max for the trained subjects (7.2 ml.kg -1 .min -1 ) implies that these subjects were possibly of differing levels of training. fewer of the trained subjects (11%) demonstrated a plateau in oxygen uptake compared with the untrained subjects (56%). although the two groups reached similar maximal hr values, large standard deviations in hrmax were evident for both trained (10 b.min -1 ) and untrained (9 b.min -1 ) groups, highlighting the inter-individual variability of this measure. no significant differences in maximal rer responses were found between the two samples with both samples below the criteria of 1.15 (table ii). the lactate concentration was significantly higher in the untrained subjects (13.5 mmol.l -1 ) than the trained individuals (10.3 mmol.l -1 ). perceptual responses were maximal (≥18) and similar for both sets of participants. significant differences between the trained and untrained individuals were also evident for peak treadmill running speed and test duration. overall, the trained group reached table i. descriptive characteristics of the subjects trained (n=8) untrained (n=9) age (yrs) 22.0±1.7 21.6±1.4 height (cm) 181.1±4.8 178.1±3.5 weight (kg) 75.3±8.3 77.3±5.1 bmi (kg.m -2 ) 22.9±2.6 24.2±1.8 bmi = body mass index. table ii. maximal oxygen uptake (vo2 max: mlo2. kg-1.min-1) maximal heart rate (hrmax: beats.min-1), maximal respiratory exchange ratio (rer), maximal rating of perceived exertion (rpe), peak treadmill running speed (km.h-1) and time taken to complete the protocol (min) trained (n=8) untrained (n=9) vo2max 70.0±7.2 54.5±3.6* hrmax 196±10 199±9 rermax 1.13±0.09 1.07±0.06 lamax 10.3±4.6 13.5±2.4* rpemax 20.0±0.5 18.0±1.5 peak speed 19.8±1.4 16.3±1.0* test duration 9.12±1.4 5.12±1.2* *significant difference (p <0.05). table iii. percentage (%) of trained compared with untrained runners who met the bass criteria as well as the magnitude of the difference in criteria attainment between the two groups magnitude of the trained untrained difference between (n=8) (n=9) samples (%) vo2 plateau 11 56 18 hrmax (b.min -1 ) 67 89 18 rermax 67 33 28 lamax (mmol.l -1 ) 89 100 9 rpemax 100 67 27 20 sajsm vol 21 no. 1 2009 a higher peak treadmill running speed (19.8 km.h -1 compared with 16.3 km.h -1 ) and ran for approximately 4 minutes longer than their untrained counterparts. table iii shows that the percentage attainment of the british association of sport sciences criteria differed considerably between the trained and untrained subjects. only 11% of the trained individuals and 56% of the untrained subjects met the criteria for vo2 plateau. thus a total of only 34% of the subjects achieved the criterion of a plateau in oxygen uptake, suggesting that this is a poor criterion to indicate maximal effort. the hr criterion was achieved by more of the untrained subjects while the rer criterion was achieved by more of the trained subjects. all the trained subjects met the rpe criteria, while only 67% of the untrained subjects attained this criterion. the lactate criterion was met by all of the untrained subjects but not by all of the trained individuals (89%). overall, a higher percentage of the trained individuals met the british association of sport sciences criteria for rer and rpe and a greater percentage of the untrained individuals met their criteria for hr, vo2 plateau and lactate. discussion the most important finding of this study was that a higher percentage of the trained individuals met the british association of sport sciences criteria for rer and rpe and a greater percentage of the untrained individuals met the criteria for hr, vo2 plateau and lactate. this implies that perceptual responses are possibly more important for determining the point of maximum exhaustion specifically in trained individuals whereas physiological responses, particularly lactate, give a better indication of maximal effort in less trained individuals. an important finding was that of the 18 subjects who participated in the study, none of them met all 5 criteria prescribed by the british association of sports sciences. 2 the lactate criterion was the most easily achieved standard, with 94% of total subjects attaining a lamax of greater than 8mmol.l -1 . this suggests that the lactate criterion is the most accurate marker of maximal effort, a finding supported by jacobs 9 and howley et al., 10 who maintain that variations in exercise performance are more accurately explained by lactaterelated variables compared with other variables including vo2max. consequently the lactate criterion should be more widely used to indicate when vo2max has been achieved, especially in the absence of a vo2 plateau. although the hr standard was met by 78% of all subjects, this criterion should not be used to confirm the attainment of vo2max because it had a high inter-individual variability. the rer standard was only achieved by half of the subjects who participated in this experiment. the inability of all individuals to reach the rer criterion even when a plateau in vo2 is exhibited corresponds to findings by howley et al. 10 therefore, the rer criterion, like the vo2 plateau standard, is not a consistent marker of maximal effort. not all of the untrained subjects fulfilled the british association of sports sciences criteria for rpe although it did appear that they were exhausted at the end of the maximal test. the failure of some of the untrained subjects to attain this standard could be attributed to incorrect ratings of perceptual responses and a suppression of feelings of fatigue. thus the rpe criterion in itself is not an unreliable marker of maximal effort, particularly in well-trained athletes. however, in order to ensure the reliability of this standard, it is vital that all subjects have a comprehensive understanding of the concept of rpe. from this investigation it would appear that the criteria for lactate, rpe and hr should be used in combination to accurately determine the attainment of maximal oxygen uptake. this is because these three standards were met by most of the subjects. contrastingly, it has been documented that the use of the rer and lactate criteria together increase the probability that vo2max is achieved. 11 this inconsistency in results highlights the need to determine which of the bass criteria, and in which combinations accurately determine the achievement of maximal oxygen uptake, because it may vary between trained and untrained individuals. the differences in the attainment of the british association of sports sciences criteria between the two samples (table iii) were greatest for rer and rpe, implying that these standards are unreliable markers of maximal effort when comparing trained and untrained groups. an 18% difference in the attainment of hr and vo2 plateau between the two samples was also apparent, indicating that these two criteria are also unreliable for this type of comparison. there was only a 9% difference in the attainment of the lactate criterion between the trained and untrained individuals, suggesting that this criterion is the most reliable when comparing trained and untrained people at maximal effort. however, it has been postulated that lamax values vary considerably, 12 especially among athletes with similar abilities, which undermines the ability of this variable to predict vo2max. 13 these data should be interpreted in the context of the differences in training status of the two groups. although the trained subjects had significantly higher maximal oxygen uptakes, there was only a difference of 12%. typically, endurance athletes have vo2max values approximately 40% higher than their sedentary counterparts. 6 this can be explained by the fact that the majority of the trained subjects were not elite athletes, having only competed at university and provincial levels. conversely, some of the untrained subjects may be genetically predisposed to superior performance, as it is well known that differences in vo2max between individuals often result from genetic, as opposed to training factors. 6,7,14 this suggests that in a heterogeneous sample, vo2max, peak treadmill running speed (workload) and total test time are likely to be significantly higher in trained individuals while the other responses, excluding lactate, are likely to be similar. in addition, trained individuals are less likely to achieve the criterion of a plateau in the o2 uptake curve. data from this study acknowledge that the criteria prescribed by the british association of sports sciences 2 for the termination of a maximal test cannot be accurately applied to both trained and untrained people, suggesting a revision of standards may be necessary. it is recommended that these criteria be adjusted with reference to the apparent differences in maximal physiological and perceptual responses between trained and untrained people. the discrepancies observed in the attainment of the british association of sports sciences criteria confirm the findings of st clair gibson et al. 3 that these criteria are not always met, despite subjects reaching levels of maximal exhaustion. however, because test termination was based on volitional fatigue, one cannot negate the possibility that the test was stopped before maximal values were achieved, particularly in the untrained subjects. this could have accounted for some of the differences found in criteria attainment between the trained and untrained individuals. nevertheless, numerous studies have substantiated that the criteria used to assess the attainment of vo2max are limited. 3,7,10,11,15,16 consequently the british association of sports sciences criteria used to demonstrate the attainment of vo2max must be used with caution, especially when the sample group includes both trained and untrained individuals. sajsm vol 21 no. 1 2009 21 references 1. mitchell jh. the physiological meaning of the maximal oxygen intake test. j clin invest 1958;37:538. 2. british association of sport sciences. position statement on the physiological assessment of the elite competitor, 2nd ed. leeds (uk); 1988. 3. st clair gibson a, lambert mi, hawley ja, broomhead sa, noakes td. measurement of maximal oxygen uptake from two different laboratory protocols in runners and squash players. med sci sports exer 1999;31:1226-1229. 4. *matter m, sitfall t, adams b, et al. the effects of iron and folate therapy on maximal exercise performance in iron and folate deficient marathon runners. clin sci 1987;72:415-422 (see noakes et al., 1990). 5. noakes td, myburgh kh, schall r. peak treadmill running velocity during the vo2max test predicts running performance. j sports sci 1990;8:3545. 6. mcardle wd, katch fi, katch vl. exercise physiology-energy, nutrition and human performance, 5th ed. baltimore: lippincott williams and wilkins; 2001. 7. shephard rj. tests of maximum oxygen intake: a critical review. sports med 1984;1:99-124. 8. borg g. psychophysical bases of perceived exertion. med sci sports exerc 1982;14:377-381. 9. jacobs i. blood lactate: implications for training and sports performance. sports med 1986;3:10-25. 10. howley et, bassett dr, welch hg. criteria for maximal oxygen uptake: review and commentary. med sci sports exerc 1995;27:1292-1301. 11. duncan ge, howley et, johnson bn. applicability of vo2max criteria: discontinuous versus continuous protocols. med sci sports exerc 1997;29:273-278. 12. bishop p, martino m. blood lactate measurement in recovery as an adjunct to training. sports med 1993;16:5-13. 13. hawley ja, myburgh kh, noakes td. maximal oxygen consumption: a contemporary perspective. south africa: department of physiology, university of cape town medical school; 1994. 14. noakes td. the lore of running. cape town: oxford university press; 1989. 15. *green hj, patla ae. maximal aerobic power: neuromuscular and metabolic considerations. med sci sports exer 1992;24:28-46 (see st clair gibson et al., 1999). 16. *noakes td. challenging beliefs. med sci sports exer 1997;29:571-590 (see st clair gibson et al., 1999). 22 sajsm vol 21 no. 1 2009 commentary 138 sajsm vol 23 no. 4 2011 the complexities of return-to-sport decisions are not unfamiliar to healthcare professionals working with elite and recreational athletes. medical advances and effective rehabilitation protocols have increased the potential for returning athletes to competition more quickly. however, these advances cannot keep up with the increasing expectations for athletes to perform at continually higher levels. these expectations are compounded by both the large financial rewards apportioned to most professional athletes; and increasing media attention, which creates additional social pressure. 1 it is therefore acknowledged that both physical and psychological aspects of injury need to be addressed to ensure holistic injury recovery. 2 the ethical issues in making return to sport decisions might not seem that prominent in many cases. however, one of the main ethical issues that have been identified by healthcare professionals working with athletes and sports teams is the tension between the long-term welfare of an athlete and premature demands to return an athlete to sport. 3 perhaps one of the most publicised cases related to return-tosport decisions and long-term welfare of athletes is that of national football league (nfl) player andre waters. waters was a former pro bowl safety for the philadelphia eagles. in 1994 he told a local newspaper that he ‘had lost count of the number of concussions he suffered at 15’. following his retirement from the game, he suffered from severe clinical depression. he died at 44 years of age, from a self-inflicted gunshot wound to the head. the forensic pathologist who performed the postmortem examination stated that ‘water’s brain resembled that of an octogenarian alzheimer’s patient’ and attributed the marked brain damage to water’s repeated injuries as an nfl player. 4 in addition, guskiewicz et al. 5 determined that retired nfl players with a history of three or more concussions were three times more likely to be diagnosed with depression, compared with retired players with no history of concussion. this case demonstrates the impact of short-term return-to-sport decisions on the long-term welfare and future societal participation of an athlete. it also highlights the need to consider ethical issues when making return-to-sport decisions. the first challenge for healthcare professionals working with teams is to recognise potential conflicts of interest that may influence return-to-sport decisions. healthcare professionals are responsible for the welfare of the team as a whole, but must also protect the health of individual athletes. strong emotional involvement in a team’s success may lead to a loss of objectivity when making decisions regarding individual athletes. 6 there may also be conflicting duties between the care of an athlete and contractual obligations to team management or sports governing bodies. such conflicts of interest may increase the risk of harm to individual athletes, and may also threaten the integrity of healthcare professionals. 3 as return-to-sport decisions are needed on a regular basis, healthcare professionals should show increased self-awareness to recognise how conflicting interests may influence decision-making, and should disclose potential conflicts of interest to athletes when providing care and advice. if the healthcare professional is unable to make an objective decision, an impartial external professional should be consulted. return-to-sport decisions should also promote an athlete’s autonomy. autonomy allows for self-determination and the individual governance of actions. autonomy is linked to informed consent, and allows an athlete to actively participate in return-to-sport decisions. however, maintaining full and thorough informed consent in return-tosport decisions may be problematic, particularly due to the numerous external pressures associated with team sports. it may be difficult to preserve individual athlete autonomy with external pressures such as financial gain and coach, team, family and public expectations. return-to-sport decisions may also be strongly influenced in competition or match situations by desires to compete, to win, and to avoid disappointing team members. the fims code of ethics regarding return-to-sport decisions states: ‘it is the responsibility of the sports medicine physician to determine whether the injured athletes should continue training or participate in competition. the outcome of the competition or the coaches should not influence the decision, but solely the possible risks and consequences to the health of the athlete.’ 7 in return-to-sport decisions, the primary obligation of healthcare professionals is to the individual athlete. sufficient and appropriate information should be given to an athlete to facilitate informed decision-making. 6,8,9 the healthcare professional should therefore confirm that an athlete understands the risks and benefits associated with return-to-sport decisions, and must also appreciate the extent of external pressures on an athlete that may influence decision-making. in addition, athletes must be educated regarding the importance of reporting injuries, to ensure effective management and to facilitate an efficient and safe return to sport. the core ethical principle of beneficence must also be considered in return-to-sport decisions. promoting beneficence is complex, particularly due to the inherent risks associated with participating and competing in most sports. 9 there are also difficulties associated with identifying and quantifying the often apparent short-term benefits, compared with the potentially uncertain long-terms harms of return to sport. external pressures and associated short-term benefits such as fame and financial reward may compel an athlete to return to sport too soon. 1,6 unfortunately, the potential long-terms harms may often be uncertain because of a lack of scientific evidence. when making return-to-sport decisions, the relative benefits should outweigh the potential harms. 9 in addition, an athlete should be informed of the existence of clinical uncertainty to promote autonomous decisionmaking when performing a risk/benefit analysis. 4 healthcare professionals working with sports teams have a fundamental responsibility to promote the health and well-being of athletes. 6,8,9 however, return-to-sport decisions may often challenge the clinical decision-making processes of healthcare professionals and judgements regarding the best interests of an individual athlete. it is necessary to appreciate the various influences and pressures that exist in recreational and professional sporting environments. return-to-sport decisions should be guided by the central ethical theresa l burgess (bsc (physiotherapy), phd (exercise science)) division of physiotherapy, department of health and rehabilitation sciences, groote schuur hospital, cape town correspondence to: theresa burgess (theresa.burgess@uct.ac.za) ethical issues in return-to-sport decisions sajsm vol 23 no. 4 2011 139 principles of autonomy, beneficence and non-maleficence. increased self-awareness and reflection regarding ethical issues are required to make return-to-sport decisions that promote the current and future welfare of athletes. references 1. bauman j. returning to play. the mind does matter. clin j sport med 2005;15:432-435. 2. podlog l, dimmock j, miller j. a review of return to sport concerns following injury rehabilitation: practitioner strategies for enhancing recovery outcomes. phys ther sport 2011;12(1):36-42. 3. anderson l, gerrard d. ethical issues concerning new zealand sports doctors. j med ethics 2005;31:88-92. 4. goldberg d. concussions, professional sports, and conflicts of interest: why the national football league’s current policies are bad for its (players’) health. hec forum 2008;20(4):337-355. 5. guskiewicz k, marshall s, bailes j, mccrea m, harding h, matthews a et al. recurrent concussion and risk of depression in retired professional football players. med sci sports exerc 2007;39(6):903-909. 6. johnson r. the unique ethics of sports medicine. clin j sport med 2004;23:175-182. 7. international federation of sports medicine: code of ethics. september, 1997. www.fims.org/en/general/code-of-ethics (accessed 22 november 2011). 8. dunn w, george m, churchill l, spindler k. ethics in sports medicine. am j sports med 2007;35(5):840-844. 9. devitt b, mccarthy c. ‘i am in blood stepp’d in so far...’: ethical dilemmas and the sports team doctor. br j sports med 2010;44(3):175-178. introduction the classification of south africans into racial populations was established during apartheid to discriminate and legalise racial segregation. south african citizens have consequently suffered from racial labelling. racial controversies smear the newpapers regularly and cricket players’ careers have at times been adversely affected.1-3 it is hoped that south africa will reach a stage where race does not play a role in sport and team selection is based only on merit. it is further hoped that these teams are representative of all south africans. how far is south africa from reaching this goal in cricket? to answer this question, racial classifications used by the south african government and the current cricket controlling body, cricket south africa (csa), were employed. many have argued against the validity of using race as a classification, especially in medical research, as genetic similarities between races far outweigh the differences.4,5 however, to understand the progression of cricketers who have been disadvantaged because of apartheid, it is necessary to racially categorise players. according to the broad-based black economic empowerment act6 and csa,7 the word ‘black’ is used for all people african, coloured or indian. however, the words ‘black african’ are also used and refer to blacks who were historically worst disadvantaged.7,8 therefore, to adhere to the policy of csa, but also to distinguish between black african and other black players (coloured and indian), the following categorisation will be used in this article: white, coloured/indian and black african. csa does not distinguish between coloureds and indians and therefore they were pooled into a single group. in 1991, at the start of the cricket unification process (the merger of all racial populations under one cricketing body), the united cricket board of south africa (ucbsa) was formed. ucbsa needed to redress the injustices caused by apartheid to transform south african cricket to be representative of all south africans.9 consequently, a national transformation charter and pledge to the nation was adopted in 1998 by the ucbsa.8 this charter covered 10 fundamental areas or thrusts. one of the main aims of the transformation process is highlighted in the thrust ‘redress and representivity’. this states that it is: ‘our historic and moral duty to ensure that cricket grows and flourishes among the truly disadvantaged of society, with the recognition that the majority of disadvantaged come from our black african communities. this involves a commitment to develop potential among our black african people at all levels of the game. this programme reaffirms our mission to bring cricket to all the people of south africa and facilitate a culture of non-racialism.’8 to achieve this, ucbsa started a development and targeted transformation programme. the development programme aimed at developing disadvantaged communities. development of facilities, coaches, administrators and cricketing skill was primary on the original research article effectiveness of the cricket transformation process in increasing representation and performance of black cricketers at provincial level in south africa abstract objectives. this study investigates the effectiveness of the cricket transformation process in firstly increasing representation of black players and secondly improving performance of black players in the south african 4-day provincial competition between the 1996/1997 and 2007/2008 cricket seasons. methods. cricketers were categorised as white, black african or coloured/indian. whenever the category ‘black’ is mentioned alone, it refers to black african and coloured/indian. all data were obtained from www.cricinfo.com. results. the number of white players decreased and the number of black african and coloured/indian players increased between the 1996/1997 and 2007/2008 seasons. white batsmen had significantly higher batting averages than black africans, but were only better than coloureds/indians in the 2001/2002 season. coloureds/indians had better batting averages than black africans in all seasons except 2001/2002 and 2004/2005. there was a significant improvement in the batting averages of coloureds/indians but not of whites and black africans over the 12 seasons. white bowlers had significantly better bowling averages than coloured/indian bowlers for seasons 2002/2003, 2004/2005 and 2006/2007. there were no significant differences in the bowling averages between white and black african players and between coloured/indian and black african players over the 12 seasons. there was a tendency towards a decreased bowling performance for coloureds/indians, whereas there was no significant decrement in the bowling performance for whites and black africans over the 12 seasons. conclusion. the increase in the number of black cricketers performing according to standard suggests a reasonable successful transformation process. however, representation and batting performance of black african batsmen remain a concern. correspondence: sharhidd taliep department of sport management cape peninsula university of technology po box 652 cape town 8000 e-mail: talieps@cput.ac.za m sharhidd taliep (phd) department of sport management, cape peninsula university of technology, cape town 156 sajsm vol 21 no. 4 2009 agenda.10-12 ucbsa spent an enormous amount of money on this and in 2002 the ucbsa’s operational budget for development was r154 million.11 the belief was that developing the infrastructures and resources of previously disadvantaged communities would result in improved performance and skill enhancement within the communities. the result envisaged was a provincial and national team representing all south africans. transformation targets are an important part of the vision and policy of csa and a south african constitutional requirement.13 currently, csa subscribes to targeted transformation set for all representative cricket, i.e. that in all national and provincial teams a certain target of black players should be reached. the transformation policy target of csa for the national and franchise (provincial) teams is 4 black players.7,8 if this target is not reached, an explanation should be provided to the president of csa. if the president does not accept the explanation, he has the power of veto.8 this transformation policy has often resulted in controversy.1-3 one of the most contentious of these relates to charl langeveldt and andre nel in 2008. charl langeveldt, a coloured fast bowler, was allegedly selected to replace andre nel, a white fast bowler, to achieve a transformational target.1 langeveldt, upon hearing this, quit the touring squad to india. another example is south african born kevin peterson who believed that the transformation process in south africa hindered his chances of playing for the south african national team.3 consequently, he left to play cricket in england. the aim of this study is not to delve into these controversies surrounding transformation. it is imperative though to monitor the success of this transformation process to accurately determine its effectiveness in producing skilled and competent black cricketers in south africa. one way to monitor the success of transformation is to observe the change in the number of black players over time. another way is to observe the change in their performance over time. the aim of this study is therefore to present data of all south african cricket players participating in the 4-day provincial competitions (currently referred to as the supersport series) over the past 12 seasons (from the 1996/1997 to the 2007/2008 cricket seasons) – firstly to observe how the numbers of players have changed, and secondly to observe how their performances have progressed. the results of this study will provide insight into the success of the cricket transformation process in south africa. methods all data were taken from www.cricinfo.com and reflect all cricketers participating (including national players) in the 4-day provincial competitions between the 1996/1997 and the 2007/2008 cricket seasons. a batsman was defined as any player who batted in a match. a bowler was defined as any player who bowled in a match. however, it is possible that certain racial populations are more suited to a particular skill in cricket. for example, black africans might be more suited to bowling than batting. if this is the case, their low batting averages would not truly reflect the performance of the black africans who were selected for the main purpose of batting. therefore, specialist batsmen and specialist bowlers were also classified. specialist batsmen were classified as players who regularly bat from position 1 7 in the batting line-up. a specialist bowler was classified as a player who regularly bowls in matches. batting average was defined by the average number of runs per batting inning. higher batting averages represent better batting performance. bowling average was defined as the average number of runs conceded per wicket taken. lower bowling averages represent better bowling performance. the number of cricket teams playing in the provincial competition changed on three occasions between 1996/1997 and 2007/2008. from the 1996/1997 to the 1998/1999 season there were 9 teams, from the 1999/2000 to the 2003/2004 season there were 11 teams, and from the 2004/2005 to the 2007/2008 season there were only 6 teams. statistical analyses to observe the change in the number of players over time, the average number of players per team was presented. linear regression analysis was used to compare the change in the number of white, coloured/indian and black african players per team across the 12 seasons. linear regression analysis was also used to compare the change in the median batting and bowling performance over the 12 seasons. medians were used instead of means for these regression analyses because before the 2000/2001 season the number of black fig. 1 (a). representation of the total number of players in the 4-day provincial competition across the 12 seasons, and (b) representation of the average number of players per team in the 4-day provincial competition across the 12 seasons. 0 50 100 150 200 white coloured/indian black african 1996/ 1998/ 2000/ 2002/ 2004/ 2006/ 2008/ 1997 1999 2001 2003 2005 2007 2009 a season t ot al n um be r of p la ye rs 0 10 20 white (r2= 0.66, r= -0.81 , p= 0.0012) coloured/indian (r2= 0.88, r= 0.94 , p< 0.0001) black african (r2= 0.89, r= 0.94 , p< 0.0001) 1996/ 1998/ 2000/ 2002/ 2004/ 2006/ 2008/ 1997 1999 2001 2003 2005 2007 2009 season b a ve ra ge n um be r of p la ye rs pe r t ea m t o ta l n u m b er o f p la y er s a v er ag e n u m b er o f p la y er s p er t ea m sajsm vol 21 no. 4 2009 157 africans and coloureds/indians was small and their data were not normally distributed. univariate analysis of variance was used to determine the difference between the mean batting and bowling performance of the different racial populations between the 2000/2001 and 2007/2008 seasons. univariate analysis was not done on the data before the 2000/2001 season because of the very small number of black african players. significant difference was set at p<0.05. when the data accounted for specialist batsmen and bowlers, the sample size was often too small for statistical comparisons between populations. the median specialist batsmen and bowlers’ performance data were therefore presented across the 12 seasons without any further statistical analysis. results total number of players the total number of players in each cricket season is presented in fig. 1a. in the 1996/1997 season there were 147 white, but only 7 coloured/indian and 2 black african players participating in 4-day matches. in the 2007/2008 season there were 72 white, 29 coloured/ indian and 14 black african players. the results of the linear regression analysis indicate a significant decrease in the number of white players per team (r2=0.66, r=-0.81, p=0.0012) and a significant increase in the number of coloured/indian (r2=0.89, r=0.94, p<0.0001) and black african (r2=0.88, r=0.94, p<0.0001) players per team across the 12 seasons (fig. 1b). the total numbers of specialist batsmen and bowlers per team are presented in fig. 2. there was a significant decrease in the number of specialist white batsmen per team (r2=0.61, r=-0.78, p= 0.0025) and a significant increase in the number of coloured/indian (r2=0.91, r=0.95, p<0.0001) and black african specialist batsmen per team (r2=0.69, r=0.83, p<0.0001) (fig. 2a). there was a non-significant decrease in the number of specialist white bowlers per team (r2=0.28, r=-0.53, p=0.075), while both coloureds/indians (r2=0.83, r=0.91, fig. 2 (a). representation of the total number of specialist batsmen, and (b) representation of the specialist bowlers per team participating in the 4-day provincial competition across the 12 seasons. 0 2 4 6 8 10 12 a white (r2= 0.61, r= -0.78, p= 0.0025) coloured/indian (r2= 0.91, r= 0.95, p< 0.0001) black african (r2= 0.69, r= 0.83, p< 0.0001) t ot al n um be r of sp ec ia li st b at sm en pe r t ea m 0 2 4 6 8 10 1996/ 1998/ 2000/ 2002/ 2004/ 2006/ 2008/ 1997 1999 2001 2003 2005 2007 2009 b white (r2= 0.28, r= -0.53, p=0.075) coloured/indian (r2= 0.83, r= 0.91, p< 0.0001) black african (r2= 0.92, r= 0.96, p< 0.0001) season t ot al n um be r of sp ec ia li st b ow le rs p er t ea m t o ta l n u m b er o f s p ec ia li st b at sm en p er t ea m t o ta l n u m b er o f s p ec ia li st b o w le rs p er t ea m fig. 3. regression analysis of the median batting performance across the 12 seasons. 0 5 10 15 20 25 30 35 white (r2= 0.14, r= 0.37, p= 0.23) b at ti ng a ve ra ge (r un s/ in ni ng s) 0 5 10 15 20 25 30 35 coloured/indian (r 2= 0.74, r= 0.86, p= 0.0003) b at ti ng a ve ra ge (r un s/ in ni ng s) 0 5 10 15 20 25 30 35 black african (r 2= 0.018, r= -0.13, p= 0.68) 1996/ 1998/ 2000/ 2002/ 2004/ 2006/ 2008/ 1997 1999 2001 2003 2005 2007 2009 season b at ti ng a ve ra ge (r un s/ in ni ng s) b at ti n g a v er ag e (r u n s/ in n in g s) b at ti n g a v er ag e (r u n s/ in n in g s) b at ti n g a v er ag e (r u n s/ in n in g s) 158 sajsm vol 21 no. 4 2009 p<0.0001) and black africans (r2=0.92, r=0.96, p<0.0001) presented a significant increase in the number of specialist bowlers per team (fig. 2b). batting averages white batsmen had significantly higher batting averages than black african batsmen in every season (table i). however, it was only in the 2001/2002 season that the batting average of whites was significantly better than that of coloureds/indians (28.7 v. 22.0 runs/innings, p=0.047) (table i). coloureds/indians had superior batting averages than black africans in all seasons except in 2001/2002 (22.0 v. 15.3 runs/innings, p=0.183) and 2004/2005 (25.2 v. 19.8 runs/innings, p=0.365). the results of the linear regression analysis (fig. 3) indicate a significant improvement in the batting averages for the coloured/indian batsmen (r2=0.74, r=0.86, p=0.0003) but not for whites (r2=0.14, r=0.37, p=0.23) and black africans (r2=0.018, r=-0.13, p=0.68). the specialist batting performance data are presented in fig. 4. although no further statistical comparisons were made between racial populations, it appears as if batting averages of white and coloured/indian specialist batsmen are better than those of black africans in most seasons. bowling averages white bowlers had significant better bowling averages than coloured/indian bowlers for seasons 2002/2003 (35.5 v. 50.1 runs/ wicket, p=0.045), 2004/2005 (37.9 v. 55.4 runs/wicket, p=0.038) and 2006/2007 (37.1 v. 59.8 runs/wicket, p=0.004) (table ii). there were no significant differences in the bowling averages between whites and black africans and between coloureds/indians and black africans across the 12 seasons. the results of the linear regression analysis (fig. 5) indicate a tendency for a decreased bowling performance for coloureds/indians (r2=0.32, r=0.56, p=0.06), but no significant differences in the bowling averages for whites (r2=0.16, r=-0.4, p=0.2) and black africans (r2=0.01, r=-0.11, p=0.73) across the 12 seasons. the specialist bowlers’ performance data are presented in fig. 6. except for the 2002/2003, 2004/2005 and 2006/2007 seasons, where white players appear to have better bowling averages than coloured/indian players, there are no major differences between the specialist bowling performances of the three racial populations. discussion the increase in the number of coloured/indian and black african players is not surprising because of the transformation policy aimed at having a certain target of black players for provincial and national cricket. however, the success of transformation lies in the ability to perform to the standard of cricket required, otherwise it is merely ‘window dressing’.8 the performance of these players was, therefore, investigated. from the 2002/2003 season the performances of coloured/indian batsmen were on a par with those of white batssajsm vol 21 no. 4 2009 159 table i. a comparison of the mean batting averages of the different racial populations between the 2000/2001 and 2007/2008 cricket seasons (significant difference (p<0.05) represented by *) season race mean batting average (runs/innings) p-value 95% ci 2000/2001 white v. coloured/indian 26.1 v. 26.0 0.963 -7.0, 7.4 white v. black 26.1 v. 11.0 0.007 * 4.1, 26.2 coloured/indian v. black 26.0 v. 11.0 0.019 * 2.5, 27.5 2001/2002 white v. coloured/indian 28.8 v. 22.0 0.043 * 0.22, 13.5 white v. black 28.8 v. 15.3 0.002 * 5.1, 22.0 coloured/indian v. black 22.0 v. 15.3 0.183 -3.2, 16.5 2002/2003 white v. coloured/indian 28.8 v. 30.4 0.654 -8.6, 5.4 white v. black 28.8 v. 14.6 0.001 * 5.6, 30.0 coloured/indian v. black 30.6 v. 14.6 0.002 * 5.6, 26.1 2003/2004 white v. coloured/indian 30.6 v. 25.1 0.088 -0.8, 11.9 white v. black 30.6 v. 13.4 0.000 * 8.8, 25.7 coloured/indian v. black 25.1 v. 13.4 0.018 * 2.0, 21.3 2004/2005 white v. coloured/indian 32.4 v. 25.2 0.066 -0.5, 14.9 white v. black 32.4 v. 19.8 0.020 * 2.0, 23.3 coloured/indian v. black 25.2 v. 19.8 0.365 -6.3, 17.1 2005/2006 white v. coloured/indian 26.5 v. 24.1 0.524 -5.0, 9.9 white v. black 26.5 v. 12.7 0.009 * 3.5, 24.1 coloured/indian v. black 24.1 v. 12.7 0.047 * 0.2, 22.7 2006/2007 white v. coloured/indian 27.7 v. 27.6 0.976 -7.3, 7.5 white v. black 27.7 v. 12.5 0.001 * 5.9, 24.5 coloured/indian v. black 27.6 v. 12.5 0.004 * 4.8, 25.4 2007/2008 white v. coloured/indian 25.5 v. 25.9 0.985 -7.6, 7.8 white v. black 25.9 v. 9.8 0.003 * 5.4, 26.0 coloured/indian v. black 25.9 v. 9.8 0.006 * 4.6, 27.6 men. white batsmen were able to maintain a similar batting average across the 12 seasons, while coloured/indian batsmen significantly improved their batting performance. this can be seen as a transformation success for coloured/indian batsmen as both their numbers and their performances have significantly improved. however, black african batsmen have weaker batting averages than coloureds/indians and whites. more concerning is that there has been no significant improvement in the batting performance over the 12 seasons. even when only specialist batsmen are considered, black african batting performance is generally below the standard of their white and coloured/indian counterparts. furthermore, in the 2007/2008 season only 4 specialist black african batsmen (0.7 per team, fig. 2a) participated in the 4-day provincial competition. this represented the lowest number of specialist batsmen participating per team since the 2000/2001 season. it is difficult to isolate a particular reason for their poor batting performance and their poor representation in 4-day provincial cricket. it can be speculated that because batting equipment is expensive, black africans, who were disadvantaged the most during apartheid, cannot afford the equipment required to train effectively. despite this handicap great cricketers have successfully trained with basic equipment.14 the performance of black african bowlers was not significantly different to that of white or coloured/indian bowlers. similarly, black african specialist bowlers’ performances do not appear to be below the standard of whites and coloureds/indians. the similarity in performance appears to date back to the 1996/1997 season (although the data were not analysed statistically because of the table ii. a comparison of mean bowling averages of the different racial populations between the 2000/2001 and 2007/2008 cricket seasons (significant difference (p<0.05) represented by *) season race mean bowling average (runs/innings) p-value 95% ci 2000/2001 white v. coloured/indian 37.8 v. 33.0 0.520 -10.1, 20.0 white v. black 37.8 v. 46.4 0.484 -32.3, 15.3 coloured/indian v. black 33.0 v. 46.4 0.324 -40.2, 13.3 2001/2002 white v. coloured/indian 38.9 v. 38.5 0.958 -13.8, 14.6 white v. black 38.9 v. 31.9 0.488 -12.8, 26.9 coloured/indian v. black 38.5 v. 31.9 0.565 -16.0, 29.2 2002/2003 white v. coloured/indian 35.5 v. 50.1 0.045 * -29.0, -0.3 white v. black 35.5 v. 39.3 0.704 -23.8, 16.1 coloured/indian v. black 50.1 v. 39.3 0.350 -11.8, 33.4 2003/2004 white v. coloured/indian 40.8 v. 39.1 0.788 -11.1, 14.7 white v. black 40.8 v. 44.4 0.699 -21.8, 14.6 coloured/indian v. black 39.1 v. 44.4 0.603 -25.6, 14.9 2004/2005 white v. coloured/indian 37.9 v. 55.4 0.038 * -34.0, -1.0 white v. black 37.9 v. 41.2 0.766 -25.0, 18.4 coloured/indian v. black 55.4 v. 41.2 0.253 -10.2, 38.6 2005/2006 white v. coloured/indian 45.7 v. 48.6 0.712 -18.0, 12.3 white v. black 45.7 v. 38.4 0.445 -11.6, 26.3 coloured/indian v. black 48.6 v. 38.4 0.342 -10.9, 31.4 2006/2007 white v. coloured/indian 37.1 v. 59.8 0.004 * -38.2, -7.1 white v. black 37.1 v. 42.9 0.585 -26.7, 15.1 coloured/indian v. black 59.8 v. 42.9 0.143 -5.7, 39.5 2007/2008 white v. coloured/indian 29.5 v. 37.1 0.382 -24.9, 9.6 white v. black 29.5 v. 40.9 0.207 -29.2, 6.4 coloured/indian v. black 37.1 v. 40.9 0.736 -25.4, 18.0 0 10 20 30 40 50 60 white coloured/indian black african 1996/ 1998/ 2000/ 2002/ 2004/ 2006/ 2008/ 1997 1999 2001 2003 2005 2007 2009 season sp ec ia li st b at sm en 's b at ti ng a ve ra ge (r un s/ in ni ng s) s p ec ia li st b at sm en 's b at ti n g a v er ag e (r u n s/ in n in g s) fig. 4. comparison of the median batting performances of the different racial populations across the 12 seasons for the specialist batsmen. 160 sajsm vol 21 no. 4 2009 small sample size) and suggests a traditional strength in performance among black africans, rather than a process of improvement. this is substantiated in the regression analysis results, which indicate no significant improvement in the performance of black african bowlers and specialist bowlers since the 1996/1997 season. fast bowler makhaya ntini is a role model for black africans. ntini was the first black african to represent south africa and became one of south africa’s best fast bowlers. his success could have inspired other black africans to reach similar heights. it is also possible that black african bowlers are more fatigue resistant. there is evidence that black south african endurance runners are more resistant to fatigue than their white counterparts.15 this study indicates that the time to fatigue during a repetitive isometric muscle contraction was longer in black africans than in whites. bowling performance has been shown to decrease after a long bowling spell.16 it is therefore possible that black african bowlers are more fatigue resistant, allowing them to sustain high performances over extended periods. this could be a reason why the majority of black african bowlers are specialist bowlers. however, this is speculative and requires investigating. coloured/indian bowling performances were significantly weaker than those of whites during the 2002/2003, 2004/2005 and 2006/2007 seasons. furthermore, there was a tendency for a decrement in their performance from the 1996/1997 season for all bowlers and a significant decrease in bowling performance among the specialist bowlers. there is no clear reason why their bowling performance would decrease over the 12 years. however, it is possible that the decrement in performance from 1996 to 2008 is a result of good bowling performances in the 1996/1997 and 1997/1998 seasons that were never matched again. further investigation into the possible causes of the decrement in performance is required. conclusion the transformation process has been fairly effective in increasing the number of black players. the performance of coloured/indian batsmen and black african bowlers is on a par with that of whites. however, the major concern is that there are few specialist black african batsmen participating in 4-day provincial cricket and that their batting performance is below standard. if this imbalance is addressed, south african provincial team selection could be purely on merit with no reference to race. acknowledgements i would like to thank professor simeon davies, miss bridget parr and miss zizonke sigodi for their assistance and advice with regard to this article. a special thanks to mrs corrie uys for her assistance with the statistics. references 1. adams z. arendse on the nel/langeveldt fiasco. the cape times 30 may 2008:27. 2. cowley j. apartheid, not the ruling regime, brought race into south africa. new statesman 7 february 2005:59. 20 25 30 35 40 45 white (r2= 0.16, r= -0.4, p= 0.2) b ow li n g a ve ra ge (r un s/ w ic ke ts ) 20 25 30 35 40 45 coloured/indian (r2= 0.32, r= 0.56, p= 0.06) b ow li n g a ve ra ge (r un s/ w ic ke ts ) 20 25 30 35 40 45 black african (r 2= 0.01, r= -0.11, p= 0.73) 1996/ 1998/ 2000/ 2002/ 2004/ 2006/ 2008/ 1997 1999 2001 2003 2005 2007 2009 season b ow li n g a ve ra ge (r un s/ w ic ke ts ) b o w li n g a v er ag e (r u n s/ w ic k et s) b o w li n g a v er ag e (r u n s/ w ic k et s) b o w li n g a v er ag e (r u n s/ w ic k et s) fig. 5. regression analysis of the median bowling performance across the 12 seasons. 0 10 20 30 40 50 60 1996/ 1998/ 2000/ 2002/ 2004/ 2006/ 2008/ 1997 1999 2001 2003 2005 2007 2009 season white coloured/indian black african sp ec ia li st b ow le rs ' b ow li n g a ve ra ge (r un s/ w ic ke t) s p ec ia li st b o w le rs ' b o w li n g a v er ag e (r u n s/ w ic k et s) fig. 6. comparison of the median bowling performances of the different racial populations across the 12 seasons for the specialist bowlers. sajsm vol 21 no. 4 2009 161 3. main b. colour-coded proteas choice is black and white for some but a grey area for others. goal coast bulletin 16 december 2008:53. 4. kirsch r. welcome to the world medical association. s afr med j 2006;96:1003-1005. 5. sheldon t, parker h. race and ethnicity in health research. j public health med 1992;14:104-110. 6. broad-based black economic empowerment act no. 53, 2003. http:// www.info.gov.za/view/downloadfileaction?id=68031 (accessed 6 august 2009). 7. parliamentary monitoring group. cricket sa: transformation policy: selection of national cricket team. http://www.pmg.org.za/report/20080226cricket-sa-transformation-policy-selection-national-cricket-team (accessed 10 september 2008). 8. parliamentary monitoring group. cricket sa: transformation policy: selection of national cricket team. transformation background. http://www. pmg.org.za/files/docs/080226csa.pdf (accessed 6 october 2008). 9. the united cricket board of south africa. mission: the principles, aims and objectives of the ucb. http://static.cricinfo.com/db/national/rsa/ about_the_ucb/ (accessed 10 september 2009). 10. parliamentary monitoring group. united cricket board of south africa: briefing. http://www.pmg.org.za/minutes/20010910-united-cricket-boardsouth-africabriefing (accessed 6 august 2009). 11. ucbsa presentation group. presentation by the united cricket board of south africa to the parliamentary portfolio committee on sports and recreation. http://www.pmg.org.za/docs/2002/appendices/020903ucb. ppt (accessed 6 august 2009). 12. smith j, fredericks g, basson w, nyoka m, tshoma k. transformation in cricket: report submitted to the honourable minister of sport and recreation, mr n balfour. http://www.info.gov.za/otherdocs/2002/cricket. pdf (accessed 6 march 2009). 13. cricket south africa. mission and vision. http://www.cricket.co.za/mission-and-vision.html (accessed 11 june 2009). 14. shillinglaw al. bradman revisited, the legacy of sir donald bradman. manchester: the parrs wood press, 2003. 15. coetzer p, noakes td, sanders b, et al. superior fatigue resistance of black south african distance runners. j appl physiol 1993;75:18221827. 16. taliep ms, gray j, gibson asc, calder s, lambert mi, noakes td. the effects of a 12-over bowling spell on bowling accuracy and pace in cricket 162 sajsm vol 21 no. 4 2009 original research 1 sajsm vol. 29 2017 a simulated rugby match protocol induces physiological fatigue without decreased individual scrummaging performance a green, 1 phd, s kerr, 1 phd, b olivier, 2 phd, r meiring, 1 phd, c dafkin, 1 msc, w mckinon, 1 phd 1movement physiology research laboratory, school of physiology, university of the witwatersrand, south africa 2wits physiotherapy movement analysis laboratory, school of therapeutic sciences, university of the witwatersrand, south africa corresponding author: a green (andrewcraiggreen@gmail.com) the game of rugby is a high-impact sport where bouts of considerable high-intensity effort are interspersed with periods of explosive sprints, active recovery and passive recovery. [1] within a competitive match, a player can cover a distance of more than 5000 m at various velocities. [1] this exertion requires players to have a high level of endurance fitness and efficient physiological mechanisms to endure highintensity collisions and maintain effective technique in all the specialised aspects of the game. both psychological [2] and physiological, [2-5] markers of fatigue have been shown to increase following competitive rugby games. specifically, an increase in words associated with mental fatigue, selected from the profile of mental state, has been reported upon match completion. [2] regarding the objective measures of the physiological manifestation of fatigue, increased concentrations of blood metabolites, including blood urea [2] and blood creatine kinase activity, [2-5] which indicate change in metabolism and muscle damage respectively, have been previously used to identify the metabolic effects of fatigue. the individual demands of playing rugby are related to the players’ positions, [1] with backs required to participate in dynamic endurance events compared to the forwards’ moderately static, high intensity activities. [1] the scrum is a specific and major component to the game of rugby union. a scrum requires eight players (forwards) from each team to bind together to compete in a physical push for possession of the ball. [6] although much of the dynamics of the force production in a scrum as a whole is yet to be revealed, the production of individual scrummaging force is thought to be related to anthropometrical, [6] physiological [6,7] as well as biomechanical factors. [8] specific assessment of physiological factors related to individual scrummaging force production has been previously related to anaerobic power [6] and the isometric strength of the legs and back. [6,7] an electromyographic evaluation reported that the quadriceps which lower back muscle activity [7] are the biggest contributors to scrummaging force production. the purpose of this study was therefore to identify the effect of simulated fatigue on an individual’s scrummaging technique and performance. it was hypothesised firstly, that individual scrummaging forces would decline as a result of the match simulation, and secondly, that individual scrummaging kinematics would be negatively affected. methods participants twelve university-level playing forwards (body mass 106.2±13.3 kg, stature 179.5±8.4 cm) had individual scrum kinetics and kinematics measured prior to and following a simulated rugby match protocol. study approval was given by the human research ethics committee of the university of the witwatersrand (m131019) and written informed consent was obtained from the participants prior to the study. study design the study was a simulation design, conducted in the preseason (four weeks prior to the start of the inter-varsity tournament), with the squad training consisting of eight field sessions and four gym sessions per week. the match simulation was performed following the midweek rest day, replacing one of the week’s gym sessions. individual scrummaging kinetics and kinematics individual scrummaging forces were collected using an individual scrummaging ergometer at 160 hz. the accuracy of the ergometer has been reported, with good agreement in mass background: a rugby union game consists of 80 minutes of strenuous exertion. forwards are required to participate in the arduous activity of scrummaging throughout a game. objectives: the purpose of this study was to identify whether rugby-match simulated fatigue modified individual scrummaging technique and reduced performance. methods: twelve forwards (body mass 106.2±13.3 kg; stature 179.5±8.4 cm) had individual scrum kinetics and kinematics assessed prior to and following a protocol that simulated a rugby match. the simulated rugby match protocol required participants to run at various velocities and perform rugby specific tasks. rating of perceived exertion (rpe) was assessed using a 6-20 borg scale and visual analogue scale (vas). blood lactate, heart rate and rpe were measured prior to, at mid-point and after the simulated game, while markers of muscle damage (blood creatine kinase activity (ck) and urea) were measured prior to and following the protocol. results: rpe (p<0.0001) and vas (p<0.0001) showed significant increases between the preand post-simulation values. of the physiological markers, heart rate (p<0.0001) and blood urea concentration (p=0.004) increased following the match simulation. no significant differences were observed for blood ck (p=0.281), individual scrummaging forces (p=0.433) or in the kinematic variables following the protocol. while physiological fatigue and subjective ratings of physiological fatigue may develop during a rugby simulation, no differences were observed in peak forces or in body kinematics at peak force. conclusion: physiological fatigue does not influence individual scrummaging performance and technique. keywords: exertion, kinetics, kinematics, simulation s afr j sports med 2017;29:1-6. doi: 10.17159/2078-516x/2017/v29i0a1701 http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1701 original research sajsm vol. 29 2017 2 loading and centre of pressure location determination. [9] the vertical and horizontal centre of pressure positions of the peak force and the scalar distance of the peak force from the centre of the scrum ergometer were calculated. all kinematics were collected simultaneously to the individual scrummaging kinetics using an 18 camera system recording at 100 hz [optitrack flex:v100r2 (natural point inc., corvallis, oregon, usa)] using amass software (c-motion germantown, maryland, usa). a measurement volume of approximately 12 m3 was calibrated around the scrummaging ergometer, in the area of scrummaging using a conventional wand method, until submillimetre error was established. custom written algorithms were used to analyse body positions as derived from raw marker location data in matlab 7 (mathworks, natick, massachusetts, usa). subjective ratings of physiological fatigue the individual’s rating of perceived exertion (rpe) and subjective rating of physiological fatigue were collected using a 6-20 borg scale [10] and a 100 mm visual analogue scale (vas), respectively. the vas used the terms ‘not exhausted (well-rested)’ as the lower anchor and ‘most exhausted ever experienced’ as the upper anchor. data for both ratings of physiological fatigue were collected prior to, at half-time and following the simulated rugby match protocol. objective measures of physiological fatigue heart rate was measured electrocardiographically using a powerlab 26t (adi instruments, 26t, australia) and calculated as the number of r-r intervals within one minute. surface electrocardiograph electrodes were placed on the wrists bilaterally and grounded on the right calf muscles. blood samples were collected via a finger prick using a spring-loaded lance (soft-clix pro, roche basel switzerland). all samples were analysed immediately following their collection. blood lactate was analysed using a portable blood lactate meter (lactate pro 2, arkray, kyoto, japan). blood creatine kinase activity (ck) and urea were analysed using a reflotron (roche, roche basel switzerland). the reflotron was calibrated using the manufacturer’s specified procedure. body mass was measured using a standardised digital scale (tanita bc1000plus, tanita corporation of america inc, usa). height was measure using a standardised stadiometer. procedure participants undertook a guided warm-up that included active and passive stretching and self-determined submaximal sprints (40-60% maximum) as they would prior to a match. additionally, they went through one cycle of the simulated rugby match protocol to familiarise themselves with the procedures. the simulated rugby match protocol was based on the bath university rugby shuttle test (burst). [11] this rugby match simulation requires players to run at various speeds, and perform tasks specific to an 80-minute rugby union game: rucks, mauls and scrums (table 1). minor alterations were made to the burst; two participants were tested simultaneously (ran the same cycles in the allotted time) and acted as opposition in the rugby tasks detailed below. secondly, the number of physical collisions between the two simultaneously tested individuals were safely increased. rucks were performed using a tackle shield (gilbert, grays of cambridge (int) ltd, east sussex, united kingdom) which the defender held while the attacking player completed the tackle, remained on his feet without releasing the defender, and maintained a steady leg drive for five metres. mauls were statically simulated and required the attacker to gain possession of the rugby ball by wrestling it from the defender. the defender was required to retain ball position for up to seven seconds. scrums were performed one-on-one with a passive binding engagement procedure (shoulder to shoulder), where the defending player was instructed to actively resist the attacking player, while the attacking player attempted to maximally push the defender backwards for five metres. players would alternate between attacking and defending during each task unit. the participants had a halftime break of 10 minutes following the eighth cycle, during which they were given 500 ml of water. individual scrummaging kinetics and kinematics, subjective measures of physiological fatigue (vas and rpe), heart rate and blood urea, lactate and ck concentrations were analysed before and within ten minutes after the match simulation protocol. in addition, blood lactate, vas and rpe and heart rate were collected at half-time. data reduction scrummaging back flexion was calculated as the degree of flexion between the lower and middle back around the tenth thoracic vertebra (fig. 1). the angles of the hips were calculated as the angle between the back vector (mid-hip joint centre to mid-scapula) and the femur vector (hip joint centre to knee joint centre). bilateral knee and ankle flexions were calculated as the angle of flexion between the vectors of the femur and the shank (knee joint centre to ankle joint centre), and the angle of flexion between the vectors of the shank and the foot (ankle joint centre to toe), respectively. angles of 180° indicated a straight back and full extension of the hip and knee, respectively. statistical analysis all data were tested for normality (shapiro-wilk test). all normally distributed variables are represented as mean ± standard deviations. the vas scores and heart rates were analysed using a one-way repeated-measures anova. body mass, blood ck, urea, and individual scrummaging kinetics table 1. tasks performed during the 16 individual cycle units of the match simulation. cycle unit tasks* distance speed 1. forward walk 20 m 20% maximal sprint 2. stop and turn 3. cruise 20 m 60% maximal sprint 4. stop and turn 5. jog 10 m 40% maximal sprint 6. rugby task competed against opponent † 7. backwards jog 10 m 40% maximal sprint * cycle units were repeated 16 times; † simulated ruck, maul or scrum original research 3 sajsm vol. 29 2017 and kinematics were assessed using paired t-tests. the distributions of blood lactate and rpe values are represented as median ± interquartile range and were assessed using a friedman test. all statistical analyses were performed in graphpad prism 5 (graphpad, san diego, california, usa) using a significance level p<0.05. effect sizes [12] were determined using cohen’s d and interpreted using: trivial 0≤d<0.2; small 0.2≤d<0.6; moderate 0.6≤d<1.2; large 1.2≤d<2.0; very large 2.0≤d<4.0. results subjective ratings and objective measures of physiological fatigue the rpe measured using the 6-20 borg scale (table 2) increased between the start and half-time (d=2.3) and between the start and end of the match simulation (d=3.6). no significant difference was observed in the rpe between the half-time point and the end point (d=1.0). the second subjective marker for physiological fatigue, the vas, increased significantly between the start and half-time (d=0.98), the start and end (d=1.9), and half-time and end (d=0.7) of the match simulation. heart rates were shown to significantly increase between the start and half-time (d=3.4) and start and end (d=4.0) of the match simulation, but not increase between the half-time and end points (d=0.3). assessing the objective physiological fatigue markers (table 2), blood lactate was significantly higher at half-time compared to the start (d=1.0), but no significant difference was reported between the start and end (d=0.7) or between the half-time point and end point (d=0.2) of the match simulation. there was no significant difference in ck immediately following the simulated rugby match protocol (d=0.4). a significant increase in blood urea was observed following the simulated rugby match protocol (d=1.0). body mass was significantly reduced from 106.2±13.3 kg to 105.0±12.9 kg following the rugby match simulation protocol (p<0.001; d=0.1). effect of fatigue on scrummaging kinetics and kinematics the force magnitudes, peak force centre of pressure positions and peak force position distance from centre are reported in table 3. the paired t-tests showed that individual peak forces, positional distance from the centre of the ergometer, horizontal or vertical force positions were not significantly different following the simulated rugby match. effect sizes of the kinetic measurements are considered to be trivial. there were no significant differences in the lower limb and back kinematics following the simulated rugby match protocol (table 3). effect sizes following the simulated rugby match protocol are considered to be within the range from trivial to small for the lower limb and back kinematics. discussion it was expected that individual scrummaging forces would decline as a result of the match simulation; however, no significant differences were observed in the scrum kinetic parameters. secondly it was hypothesised that the individual scrummaging technique (kinematics) would be negatively affected following the rugby match simulation protocol. contrary to the expectations of the authors and despite the evident physiological fatigue, no differences were observed in the kinematic variables following the match protocol. subjective ratings of physiological fatigue were recorded in the current study using two different subjectively reported scales, both of which showed a marked increase (very large effect size) in perceived effort. mashiko et al. [2] showed how a competitive rugby game can induce physical and mental fatigue. the results of the present study agreed with the former and others [11] with ratings of perceived exertion increasing as the duration of match simulations progresses. there were progressive increases in the subjective ratings of physiological fatigue (vas) and an increased heart rate between the start and half-time and the start and the end of the simulation. the change in heart rates corresponds with observations made in the development of the burst. [11] while heart rates were shown to increase during the protocol, the heart rates in the current study were lower than those noted by roberts et al. [11] namely, 158 beats per minute. these lower values for the heart rates may have been as a result from the electrocardiography used in this study (as compared to heart rate monitors, which fig. 1. kinematic definitions of variables in the starting position from the sagittal view. all variables are calculated bilaterally. a. back flexion, b. bilateral hip extension, c. bilateral knee flexion, d. bilateral ankle flexion. table 2. the rating of perceived exertion, heart rate and blood lactate, creatine kinase activity and urea concentrations at three time points during a rugby match simulation protocol (n=12) time point collection fatigue measurements pre halftime post mean (±sd) mean (±sd) mean (±sd) borg scale rating (au)*†‡ 6.5 (±3) 13.0 (±4) 16.5 (±5) visual analogue scale (mm)†‡§ 31 (±26) 56 (±24) 71 (±21) heart rate (beats/min)†‡ 75 (±11) 111 (±22) 117 (±21) blood lactate (mmol/l)*† 1.8 (±1.6) 3.5 (±3.6) 2.9 (±3.3) blood creatine kinase activity (u/l) 203.8 (±191.7) n/a 278.1 (±212.1) blood urea (mg/dl)‡ 34.6 (±11.5) n/a 46.5 (±12.9) *borg scale rating and blood lactate concentration are represented as median ± interquartile range au arbitrary units; n/a not analysed at this time point; † significantly different between pre and half time (p<0.05); ‡ significantly different between pre and post (p<0.05); § significantly different between half time and post (p<0.05) original research sajsm vol. 29 2017 4 may include some degree of electromyographic artefact). the heart rates reported by the roberts et al. [11] study were collected as the mean for the five minute duration throughout the simulation, whereas the heart rate measured in the current study was only collected as single short-duration measurements, with the participants seated prior to, during the half-time break and following the simulation. further differences may be related to the fitness levels of the participants in the various studies and as a result of the modified burst protocol used in the current study. in the current study blood lactate was significantly increased from before exertion to half-time, but not from half-time to post exertion or preto post exertion. even though lactate significantly increased from before exertion to half-time the concentration never went above the onset of the blood lactate accumulation threshold of 4 mmol/l. it is likely that the simulation consisted of more endurance tasks than explosive tasks and that the intensive static components were equally dispersed by active and passive recovery intervals. roberts et al. [11] reported higher peak blood lactate levels during the burst (4.4-4.6 mmol/l) compared to the half-time blood lactate values in the current study. the discrepancies in the blood lactate measurements are likely a result of the timing of blood collection. the burst study only reported peak lactate value after 20 minutes [11] whereas the current study reported the half-time value and not as a peak value. if the peak lactate occurred prior to this time it would have been missed, giving the participants the opportunity to metabolise the lactate. lactate [3] and lactate dehydrogenase [2] have been reported to be increased following a competitive rugby game recent data from morel et al. [13] would dispute that the static components of rugby are solely responsible for the increased blood lactate. they reported increases in blood lactate following scrum repetitions; however, the increase appears to be progressively lower in scrummaging compared to simulated mauling and sprinting. [13] while the match simulation may emulate the tasks performed during a rugby match, it cannot simulate the intensity of a match. it is likely that the discrepancies are related to match intensity and the number of collisions resulting in muscle trauma and muscle breakdown. significantly higher blood lactate concentrations have been reported in contact simulations compared to non-contact simulations. [14] however, it must be stressed that a direct comparison between contact simulations, repeated efforts and the tasks of the current study are not equally comparable and will undoubtedly affect the development of physiological fatigue. physical contact in a rugby game is known to cause somatic blunt trauma and results in markers of muscle damage being released into the blood. [2-4] creatine kinase activity (an intramuscular enzyme and therefore a marker of muscle damage) is known to significantly increase in the plasma following a game of rugby. [2-5] the increase has been attributed to the physical impacts between players, specifically in the tackle [3] and scrum [4] and is thought to be related to the intensity of collisions. [2,5] however, in the current study ck did not increase following the simulated match protocol. the simulated game, while incorporating physical contact, was likely to include considerably lower impact collisions (less than those experienced during an actual game). this was to ensure player safety and was deemed safe to have live one-onone scrummaging drills instead of a scrum sled. however, rucks and mauls had to be safely simulated using a cushioned tackle shield. these safety alterations undoubtedly affected the production of ck. furthermore, this lack of difference may be due to the physiological pathways by which ck presents in the blood. ck is released into the interstitial fluid resulting from muscle damage and is transported by the lymphatic system back into the blood for clearance. [4] previous studies have shown how ck normally peaks 24 hours after a rugby game. [3,5] the lack of an obvious increase in ck would tend to suggest that substantial muscle damage may not have been the cause of the subjective fatigue observed in this study, and that metabolic fatigue (blood urea and blood lactate) may have been the cause of the subjective fatigue. another metabolite known to increase with a bout of table 3. individual peak forces, centre of pressure scalar distance from centre, horizontal centre of pressure positions and vertical centre of pressure positions and individual scrummaging kinematics before and after a rugby match simulation protocol (n=12) time point collection pre post mean (±sd) mean (±sd) difference p value cohen’s d kinetic measurements peak force (n) 1720 (±363) 1679 (±355) -40.2 0.43 0.11 peak force distance from centre (m) 0.36 (±.08) 0.37 (±.07) 0.0037 0.86 0.05 peak force horizontal position (m) 0.012 (±.016) 0.016 (±.026) 0.0042 0.67 0 peak force vertical position (m) -0.36 (±.08) -0.37 (±.07) -0.0032 0.88 0.04 kinematic measures back flexion (°) 169.9 (±6.3) 170.7 (±5.4) 0.8 0.91 0.14 right hip extension (°) 107.3 (±30.4) 120.7 (±24.4) 13.4 0.15 0.49 left hip extension (°) 98.5 (±35.1) 113.9 (±33.8) 15.4 0.25 0.45 right knee flexion (°) 54.9 (±11.3) 46.7 (±22.1) -8.2 0.3 0.47 left knee flexion (°) 57.2 (±20.9) 52.2 (±21.6) -4.9 0.53 0.23 right ankle flexion (°) 90.6 (±16.6) 87.2 (±17.1) -3.4 0.62 0.2 left ankle flexion (°) 87.2 (±19.1) 90.1 (±11.2) 2.9 0.51 0.19 original research 5 sajsm vol. 29 2017 fatiguing exercise is blood urea. [2] greater blood urea concentrations have been reported following competitive rugby. [2] in rugby players an increase in blood urea was reported in the forward players and was attributed to the contact and type of game play experienced by these players. [2] similarly the blood urea concentration was shown to significantly increase over the simulated rugby match in the present study. the rugby match simulation protocol resulted in a reduction in body mass, similar to that seen in the burst (1kg in both tests). [11] the individuals’ body masses are known to be related to the individual scrum force. [6,7] therefore it was expected that the scrummaging force would decrease. however, the reduction in body mass was considered to have a trivial effect size, mainly due to the acute loss of water and not muscle mass. furthermore, there was no difference between the individual scrummaging forces prior or following the rugby match simulation protocol. the development of individual scrummaging force, however, is not solely reliant on the body mass of the individual, but is related to technique. [8] the individuals managed to attain a similar peak force before and following the simulated rugby match (effect size: trivial); however, this is in contrast to the results of morel et al. [13] their study showed that an increase in the number of scrum repetitions reduced the individual scrummaging forces. [13]. jougla et al. [15] reported no differences between the peak forces following a rugby-specific repeated sprint protocol. these two studies suggest that scrum performance is reduced by successive scrummaging attempts and not repeated sprints. it was expected that the peak scrummaging forces would be reduced following the match simulation since scrummaging is comparable with other measures of strength, [6] which have displayed a fatigue-related decline in magnitude. their intrinsic ability to maintain a competitive scrummaging force may be developed over years of training, or the lack in difference might be due to the different impact nature of sprinting or jumping as compared to the high impact nature of scrummaging. the unchanging nature of scrummaging technique may, however, support the former explanation. the resulting kinematics of the lower limbs showed that the individuals used a similar body position when applying peak force, regardless of their fatigued state. no significant difference was observed in either the peak individual forces or the body kinematics at peak force and their effect size ranged from trivial to small. known correlates of individual scrummaging peak force are the extension of the hips, knees and flexion of the ankles. [8] sharp et al. [7] reasoned that the lack of relationships between muscular activities and individual peak forces during engagement were due to a similar body position and engagement pattern used by the players. although the relationship between muscular activity and engagement forces was not investigated in the current study, the individual kinematics did not vary, possibly as a result of similar binding and individual scrummaging styles before and after the match simulation. therefore these authors assume that the resistance to change of the scrummaging technique (kinematics) to fatigue appears to be a consistent finding, similar to those by sharp et al. [7] however, further investigation into scrummaging technique and the development of fatigue is required. limitations the current study is limited by the small sample size of amateur rugby players. inclusion of additional markers of physiological fatigue and performance outcomes, such as vertical jump and sprint times would have been beneficial in identifying a decline in physical performance. in addition, the match simulation protocol may have been unable to accurately replicate a competitive match, particularly the number and intensity of collisions. it should also be noted that it is possible that fatigue during actual game play may differ from the fatigue of a simulated match such as performed here. thus more direct measures of direct match-derived fatigue may be warranted to confirm these findings. finally, greater use of the scrummaging ergometer during the match simulation could have highlighted smaller significant changes within specific parts of the match simulation. conclusion while the participants were clearly in a state of fatigue, no differences were observed in the magnitude of their peak forces or in the body kinematics at peak force. the lack of difference in the peak force despite the fatigue may suggest that individual strategies for attaining peak force are resistant to fatigue but may be multifactorial and require a more in-depth analysis. practical implications  increased perceived exertion or match-simulated fatigue does not reduce individual scrummaging force.  technically, scrummaging performance is unaffected by match-related fatigue.  due to the lack of difference in technical and physical scrummaging performances, substituting scrummaging players based solely on scrummaging performance is not recommended. acknowledgments: the authors express their gratitude to liz chase, from wits sports administration, for her assistance and the willing participants from the wits rugby club. this work was supported by the national research foundation under grant uid 83772; university of the witwatersrand, faculty of research committee individual research grant under grant 0012548521101512110500000000000000004992. references 1. quarrie kl, hopkins wg, anthony mj, et al. positional demands of international rugby union: evaluation of player actions and movements. j sci med sport 2013; 16, 353-359. 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[pmid: 5523831] 11. roberts sp, stokes ka, weston l, et al. the bath university rugby shuttle test (burst): a pilot study. int j sports physiol perform 2010; 5:64-74. [doi. org/10.1123/ijspp.5.1.64] 12. hopkins wg. a scale of magnitudes for effect statistics: a new view of statistics.2002. available at: http://sportsci.org/resource/stats/effectmag.html. accessed 20 november 2015. 13. morel b, rouffet dm, bishop dj, et al. fatigue induced by repeated maximal efforts is specific to the rugby task performed. int j sports sci coach 2015; 10:11-20. [doi:org.10.1260/1747-9541.10.1.11] 14. mullen t, highton j, twist c. the internal and external responses to a forward-specific rugby league simulation protocol performed with and without physical contact. int j sport perform physiol 2015; 10:746-753. [doi:10.1123/ijspp.2014-0609] 15. jougla a, micallef jp, mottet d. effects of active vs. passive recovery on repeated rugby-specific exercises. j sci med sport 2010; 13:350–355. [doi:10.1016/j.jsams.2009.04.004] issn 1015-5163 www.sajsm.org.za sports medicine the south african journal of a peer reviewed publication of the south african sports medicine association volume 26 | number 1 | april 2014 http://www.sajsm.org.za 12 sajsm vol 19 no. 1 2007 introduction golf is a popular sport played worldwide by people of all ages and skill levels. part of the appeal of golf is that there are no gender, skill or age limits to participation. golf participation rates vary across all age ranges and are high in the older age groups. this is partly due to the fact that those in the older/retired population have more leisure time to pursue activities and the fact that golf is low impact with a general aerobic component, which makes it a perfect recommendation for practitioners wanting their patients to exercise. golf is a popular option as it also provides social interaction and can be played at all skill levels due to its handicap system. additionally, for those people who like to remain active and competitive as they age, golf is a popular option. although uncommon, injuries do occur whilst playing golf. considering the popularity of golf, both in terms of participation and spectator rates, it is surprising that there have been only a few small studies on golf injury. gosheger et al. 8 reported that most of our understanding of golf injuries relies on two publications produced by mccarroll et al. 13 in 1990 and batt in 1992, 4 and one produced over 20 years ago by mccarroll and gioe. 14 the aims of this study were to determine the golf-related injury locations among amateur golfers across australia, to examine the common injury mechanisms in golf, and to determine if factors such as age, gender and skill level affect injury rates. as golf-related injury occurs frequently in the golf swing, this study also attempted to ascertain the golf swing phase during which most injuries occur. methods survey design a survey questionnaire comprising 53 questions was developed to collect data for the study. information was collected on age, gender, skill level, level of self-rated golfing importance, play/practice habits, type of warm-up and conditioning habits, golf-related injury in the previous 12 months, tuition, mode of club transport, and age and cost of equipment. for the purpose of this study, a golf-related injury was defined as any condition sustained during the playing/practising of golf that stopped play/practice, impeded normal performance or required medical treatment including over-the-counter medication such as analgesics, non-steroidal anti-inflammatories original research article the epidemiology of golf-related injuries in australian amateur golfers – a multivariate analysis a mchardy (bmedsc, mchiro, graddipchiro (paed), phd (cand))1 h pollard (bsc, graddc, graddipappsc, msportssc, phd)1 k luo (beng, mapplstat, phd)2 1 macquarie injury management group, department of health and chiropractic, macquarie university, sydney, australia 2 department of statistics, macquarie university, sydney, australia abstract objective. to perform an epidemiological study in order to determine the golf-related injury locations, injury rates and possible risk factors for golf injury in amateur golfers across australia. method. a retrospective cross-sectional survey of australian golf club members was used to collect data for the study. chi-square testing was used to evaluate the association between golf injury and each possible risk factor at univariate level. all the possible risk factors were further examined in multivariate analysis using logistical regression. results. there were 1 634 golfers included in the present study. of these, 288 reported having had one or more golfrelated injuries in the previous year. the most common injury location was the lower back (25.3%), followed by the elbow (15.3%) and shoulder (9.4%). the most common injury mechanism was poor technique in execution of the golf swing (44.8%). age, warm-up status, conditioning habits, wearing a golf glove/s and injury acquired in other sports / activities were significantly associated with risk of golf injury (p < 0.05). equipment use such as type of golf club shaft used, type of shoes used and other factors studied were not statistically significant. conclusion. the most injured sites identified in this study were the lower back, elbow and shoulder respectively. risk of injury during golfing varied according to age group, warm-up status, conditioning habits, whether the player wore a golf glove/s, and whether the golfer had been injured in other activities. correspondence: a mchardy po box 448 cronulla nsw 2230 australia e-mail: golfinjury@optusnet.com.au pg12-19.indd 12 4/4/07 10:30:08 am pg12-19.indd 13 4/4/07 10:30:08 am 14 sajsm vol 19 no. 1 2007 or liniments. as such, an injury was recorded if any of the three criteria were applicable. golfers who had sustained an injury in the past 12 months were asked further questions, including questions on injury onset, injury mechanism, previous history of injury, and whether treatment was sought after injury. ethics approval for this study was obtained through macquarie university. an envelope containing a cover letter stating the purpose of the study, an information/consent form, the survey and a reply-paid envelope was mailed to each member of golf clubs agreeing to participate in the study. statistical analysis each factor (e.g. age, skill level, gender, etc.) was first examined in relation to risk of golf-related injury (i.e. injury of any body site) in the univariate analysis. chi-square testing and contingency tables were used to evaluate the association between golf-related injury status, injured vs. non-injured, and each possible risk factor studied at the univariate level. factors that appeared to be important in the univariate analyses were further examined in multivariate analysis using logistical regression. 11 odds ratios and 95% confidence intervals were used to measure the strength of association between each risk factor studied, and injury. an odds ratio of 1 meant no association, i.e. the two groups compared had a similar risk of injury. if a 95% confidence interval did not contain the value of 1, this indicated that there was a statistically significant association between the risk factor studied and injury (less than 1 being a reduction in risk and greater than 1 an increased risk of injury). statistical analyses in the study were performed using the statistical software package spss (spss inc. chicago, illinois, usa), with a significance level of 5%. to determine how representative the respondents were of the australian golfing population, national handicap and male-to-female golfer distribution were compared with the data for respondents in this study. 2,3 results one thousand six hundred and thirty-four amateur golf players returned their survey forms from 10 clubs in australia (7 813 sent, response rate 21%). the average age of the 1 634 golfers was 55.2 ± 14.6 years. there were 318 females (19.5%) with an average age of 59.2 ± 12.2 years, and 1 316 males (80.5%) with an average age of 54.3 ± 15.3 years. the average handicap of female respondents was 26.3 ± 9.5, and of male respondents 18.1 ± 7.0. respondents reported that golf scored 7.4 out of 10 (± 1.9) in importance on a visual analogue scale (vas) (1 being not important, 10 being very important). a total of 288 golfers reported sustaining at least 1 injury in the past year. results analysing the 288 primary injuries were reported. the injury rates of men and women were the same (17.6%). in total, 73 golfers reported having sustained an injury to the lower back region (25.3%). in this cohort, the lower back was the most common injury site followed by the elbow (15.3%) and the shoulder (9.4%) (fig. 1). the most common mechanism of injury reported by golfers was a self-reported incorrect golf swing (44.8%), followed by overuse (25.3%) (fig. 2). regarding where in the golf swing the respondent felt that the injury occurred (fig. 3), 30.2% said the follow-through and 17.7% the downswing. those golfers who indicated ‘other’ in response to the question reported that more than 1 swing phase or specified impact and/or hitting the ground caused their injury, with impact-based injury accounting for 20% of all responses in the ‘other’ category and 6% of the overall injured golfers. a total of 57.3% of golfers who sustained an injury reported that the injury occurred over a period of time, while 46.9% of those who sustained injury reported having had a previous injury at the same injury site. golf was reported to have aggravated the injury in 72.2% of cases, while the injury was not aggravated by any activity in 14.9% of cases. almost 75% (74.7%) of those injured reported having sought treatment for their injury. of the practitioners sought, physiotherapists were sought most often (47.4%), followed by general practitioners (47.0%) and chiropractors (27.9%) (fig. 4). of the injured golfers, 4.9% reported to have stopped practising, 5.2% reported to have stopped playing, and 55.2% fig. 1. reported sites of golf injury (n = 288) in the previous 12 months. fig. 2. mechanism of injury in golfers. p e rc e n ta g e anism mechanism no response pg12-19.indd 14 4/4/07 10:30:13 am reported to have stopped both play and practice (table i). the most common length of time off practice was 2 3 weeks, followed by 1 2 weeks, while 14.5% reported having spent more than 12 weeks off practice following the injury (fig. 5). the most common length of time off from golf play was 1 2 weeks, followed by 2 3 weeks, while 12.1% reported having spent more than 12 weeks off practice following the injury (fig. 5). those variables that appeared significant in univariate analysis are presented in table ii. results showed that age, other sports / activities, golf club shafts used, glove use, golf shoe use, warm-up and conditioning habits and game / practice habits appeared significant. using multivariate analysis, these factors were further examined in relation to the risk of golf injury. the results including odds ratios and the corresponding 95% confidence intervals obtained from the multivariate analysis are presented in table iii. it was found that age remained significant after adjusting for all other factors in the multivariate analysis. golfers aged above 40 years had the highest risk: 40 59 years (or 5.7, 95% ci: 2.0 16.0), 60 69 years (or 5.4, 95% ci: 1.9 15.6), and 70+ years (or 4.4, 95% ci: 1.4 13.1), followed by those aged between 20 and 39 (or 3.8, 95% ci: 1.1 13.6), while the youngest group (under 20) had the lowest risk of injury. golfers who reported sustaining an injury in other sports or activity in the previous 12 months were more likely to have reported a golfrelated injury in the same period (or 2.2, 95% ci: 1.6 3.1). after adjusting for the other 2 warm-up variables (air swings, hitting balls), only range of motion exercises remained significant, showing a positive association with the risk of injury (or 1.6, 95% ci: 1.2 2.2). for conditioning activities, only golf-related strength work significantly increased risk of injury (or 2.7, 95% ci: 1.6 4.6). golf-specific stretching during the week was no longer significant after adjusting for golf practice activities, and general stretching and strength work were no longer significant after adjusting for golfspecific stretching and strength work in the same model. after adjusting for other golf practices, golf practices including chip-putt (p = 0.2), full shot (p = 0.4) and game play (p = 0.1) were no longer significant. the type of club shafts used by golfers was not significantly associated with injury (p = 0.05), although using steel irons / graphite woods or all graphite exhibited a greater risk of injury than all-steel shafts (or 1.8, 95% ci: 1.2 2.6 and or 1.6, 95% ci: 1.0 2.4 respectively). wearing golf gloves was associated with increased risk of injury compared with using no glove (left hand p = 0.02, 95% sajsm vol 19 no. 1 2007 15 table i. distribution of responses to the survey question ‘did your injury stop you playing / practising golf?’ injured players % n stopped practice only 4.9 14 stopped playing only 5.2 15 stopped both practice and play 55.2 159 did not stop me 32.3 93 no response 2.4 7 100.0 288 fig. 3. responses to the question ‘in what phase of the golf swing did the injury occur?’ (no response n = 32, backswing n = 29, downswing n = 51, follow-through n = 87, other n = 89, of which 18 at impact). backswing downswing follow through other no response fig. 4. practitioners sought by those who sustained an injury. is t fig. 5. time off reported by those golfers who stopped golf play / practice as a result of injury (n = 188). e pg12-19.indd 15 4/4/07 10:30:33 am 16 sajsm vol 19 no. 1 2007 ci: 1.2 2.5, both hands p = 0.00. 95% ci: 2.3 11.7). in contrast, those who wore golf shoes with rubber ripples had significantly lower risk of injury compared with those wearing no golf shoes (p = 0.02, 95% ci: 0.2 0.9). discussion the golf literature suggests that the 3 most common injury sites are the lower back, elbow and wrist, with the shoulder as the fourth most common injury site. 4,13,14 this study agreed with the literature that the lower back was the most common site of golf injury, followed by the elbow, but the shoulder was injured more often than the wrist in this sample. potential reasons for the differences between the results of this study and the literature include that the sample size of previous studies was small. additionally, there was greater potential for recall bias in golfers sampled in the previous studies requiring information on injuries over a whole golfing career, rather than just in the previous year, as in this study. 15 the chance of recall bias increases with increased recall period. 22 the most common injury mechanism found in this study was poor technique in the execution of the golf swing (aberrant mechanics), which is in agreement with the findings in the literature. 4,13,14 the amateur golfer is more likely to have an aberrant swing pattern that could predispose to injury at a rate potentially greater than that of the professional golfer. 10 most golf injuries reported in this study occurred in the golf swing. to ascertain the golf swing phase where most injuries occurred, the swing was divided into several well-defined phases including backswing, downswing and follow-through. golfers who reported that they were injured ‘at impact’, formed a separate category (‘other’) together with those reported as injured in ways other than the three phases defined above. according to the literature, the follow-through phase is the most common phase in which injury occurs. 4,13,14 this phase occurs at the end of the swing, after the ball has been hit and the body is slowing in movement. this phase is associated with the eccentric action of the trunk rotators 16,20 and lumbar hyperextension depending on the golf swing type. 17 further study is required with regard to the influence of the golf swing on injury occurrence, particularly the follow-through phase. as shown in this study, a large proportion of injured golfers sought treatment with allied health practitioners such as physiotherapists, chiropractors, and massage therapists. this implies that hospital admission-based injury epidemiology studies, where hospital records are analysed for golf-related injury, are unlikely to reflect the actual occurrence of golfrelated injury and would be skewed to more serious injury. this observation was also made by fradkin and co-workers. 7 the present study also investigated the time off golf (i.e. lost to injury) among injured golfers following their injury. over half (55.2%) of those injured reported taking time off both play and practice and a further 5% took time off either practice or play. given that over 12% of golfers with injures had over 3 months off play or practice, and nearly one-quarter had over 6 weeks off, suggests that the severity of the average golf injury may be greater than generally acknowledged by the public. according to this study, golfers over the age of 40 years had the highest risk of injury. golfers in the 40 59-year and the 60 69-year age groups were over 5 times more likely to sustain an injury than golfers under the age of 20 years, table ii. summary of variables considered in multivariate analysis variable categories analysed age 0-20 20-29 30-39 40-59 60-69 70+ other sports / activities yes no club shafts all steel steel irons/graphite woods all graphite graphite irons/steel woods wear golf shoes no yes/plastic spikes yes/rubber ripples yes/metal spikes no response glove use no yes left hand yes right hand yes both hands warm-up habits no warm up air swing hit balls conditioning habits no general stretching golf-specific stretching general strengthening golf-specific strengthening game / practice habits chipping / putting 0-1 1+ full shot 0-1 1-2 2-3 3+ game play 0-9 holes 1-2 rounds 3 rounds 4+ rounds pg12-19.indd 16 4/4/07 10:30:33 am sajsm vol 19 no. 1 2007 17 with those over 70 years over 4 times more likely to injure themselves. the frequency of injury in golf may be due to the potential for a cumulative effect of injury as more than half of the injuries sustained were of insidious onset, and nearly half had been sustained previously (recurrent). those golfers who sustained a recurrent injury from participation and injury incurred in another sport / activity may have done so due to incomplete healing of a previous injury. such mechanical inefficiency due to the previous injury may have resulted in compensatory muscle activity and secondary muscle activation, altering the efficiency of the golf swing. this is a well-known injury factor, resulting in increased injury potential. a prospective cohort study could be used to further ascertain the relationship between swing mechanics and injury, using a representative sample of injury-free golfers. surprisingly, wearing golf gloves was associated with an increased risk of injury. golf gloves are designed and used to improve the grip on the club, reducing the risk of slippage through greater friction between the club and the glove. however, variable grip pressure has been noted during the golf swing, with change in the forearm flexor force during the swing. 5 change in grip pressure and positioning of the table iii. results summary from the multivariate analysis exp (b) 95.0% ci for true or variable p-value i.e. or lower coefficient age (0-20 baseline) 0.011 20-29 0.041 3.799 1.058 13.641 30-39 0.043 3.206 1.035 9.926 40-59 0.001 5.654 1.993 16.037 60-69 0.002 5.386 1.855 15.639 70+ 0.009 4.364 1.448 13.146 no response 0.686 1.455 0.236 8.952 injuries in other activity (yes vs no) 0.000 2.227 1.577 3.143 club shafts (all steel baseline) 0.055 steel irons/graphite woods 0.007 1.761 1.171 2.649 all graphite 0.034 1.569 1.036 2.376 graphite irons/steel woods 0.893 1.115 0.228 5.457 wear glove (0 = 'no' as baseline) 0.000 yes left hand 0.002 1.737 1.216 2.483 yes right hand 0.043 1.688 1.017 2.802 yes both hands 0.000 5.139 2.258 11.698 wear golf shoes (0 = 'no' as baseline) 0.082 yes/plastic spikes 0.186 0.633 0.321 1.247 yes/rubber ripples 0.022 0.420 0.200 0.882 yes/metal spikes 0.552 0.771 0.328 1.814 no response 0.128 0.418 0.136 1.285 play practice warm-up range (yes vs no) 0.001 1.627 1.228 2.154 during week condition golf strength (yes vs no) 0.000 2.669 1.563 4.556 chip-putt (≥ 1 vs 0 1) 0.237 1.280 0.850 1.926 frequency full shot practice (0-1 as baseline) 0.417 1-2 0.131 1.385 0.908 2.114 2-3 0.251 1.500 0.750 2.997 3+ 0.683 1.215 0.476 3.102 frequency game play (0-9 holes as baseline) 0.103 1-2 rounds 0.017 1.803 1.113 2.920 3 rounds 0.029 1.996 1.074 3.710 4+ rounds 0.210 1.664 0.751 3.688 pg12-19.indd 17 4/4/07 10:30:34 am 18 sajsm vol 19 no. 1 2007 forearm during the golf swing may lead to excessive cocontraction of the forearm extensors, potentially reducing the available range of motion to be exercised during the dynamic movement, thereby predisposing to increased eccentric muscle loading and injury. 18 variability in grip pressure may be related to injury rate and should be investigated further. an accepted tenet in sports medicine is that a warm-up can minimise or reduce injury rates. 26 however it is felt that whilst warm up prior to activity may be able to prevent muscular injuries, improper or excessive stretching and warming up can predispose to injury. 23 surprisingly, in this study range of motion exercises were associated with an increased risk of injury. often this type of activity includes bouncing the body through the movement when the tissues are cold, akin to ballistic stretching. it is now believed that ballistic stretching (i.e. bouncing) is associated with increased injury rates. 24 this predisposes the golfer who performs range of motion exercises to injury. those performing air swings and hitting the ball as part of a warm-up process did not increase the risk of injury compared with the no warm-up group. in this cohort, golfers appeared to be more responsive to these types of warm-up activities. further prospective investigation is required into the type of warm-up used (range of motion, air swings, hitting the ball, stretching), as well as how long and how often the warm-up exercises were performed prior to play in relation to injury generation. strength work, which was reported by respondents to be golf-specific, significantly increased the risk of injury, raising the question whether such activity benefits the golfer at all. as this survey was self-reporting of activity at a very cursory level, it is difficult to speculate why golf-related strengthening appeared to be associated with increased injury risk. it may not be causative at all and may constitute an aberrant statistical finding of association only. however, possible factors include overuse-related injuries and performing activities that are not conducive to improving the golf swing in terms of strength, speed or quality of movement; this may predispose players to injury due to the generation of incorrect muscle-firing patterns when compared with the ideal. univariate analysis found that the amount of chip-putt full shot practice and game play were significant in injury generation, with those who performed more activity in each group more likely to be associated with injury. however, after taking into account the potential for confounding, where the effect of one factor on an outcome is distorted by a second factor, it was found that play / practice habits were no longer significant. a limitation of the study was the self-reporting nature of the survey and reliance on the responder to answer questions correctly. this is particularly the case when asking about injury mechanism and when the injury occurred. whilst an aberrant swing as an injury mechanism was not identified by someone else (for example a golf professional), golfers have a basic concept of their golf swing. as such an individual would be able to determine that their golf-related injury was predisposed by their swing. in a similar way the golfer would be able to identify that the pain during his/her golf swing could be broadly categorised into the phases of the golf swing, viz. backswing, downswing and follow-through. the response rate achieved in this survey was 21%. compared with a 60% and over response rate, which is considered excellent, 22 this is a low value. many studies improve response rates by mailing multiple reminders / surveys to non-responders, which can increase response rates to over 70%, 1,25 but such studies generally involve smaller, discrete sample sizes and/ or very large budgets. it is likely that without large budgets, repeated national mail-out would be too costly. the accepted survey response rate for a single mail-out to a large sample size is 15 30%, 6,9,12,13,19 a range which the present study falls within. the primary concern with a low response rate remains how representative the respondents are of the population being examined. 21 however, a low response rate does not automatically imply that a non-representative sample has been selected. researchers appear more concerned about the likelihood of bias in the collection of the sample rather than the specific sample size in isolation. 1,25 analysis of the latest australian bureau of statistics data on sports participation and australian golf union data on average handicaps show that the present study achieved a comparable maleto-female breakdown ratio (82.2% vs 17.8% and 80.5% vs 19.5%) 2 and comparable handicaps (male 18.1 and female 27.5 compared with 18.1 and 26.3). 3 we conclude that our data appear to be reasonably representative of the general population of golfers. the above data will become baseline data for a prospective study that will determine the 1-year golf incidence rate in australian amateur golfers. conclusion this epidemiological investigation of golf injury found that the lower back, elbow and shoulder are the most commonly injured areas, and that these injuries were most likely caused by some part of the golf swing. three-quarters of all injured golfers sought treatment for their ailment. risk of injury during golfing varied according to age group, warm-up status, conditioning habits, whether the player wore a golf glove, and whether the golfer was injured in other sports/activities. golf is one of the most popular sports played by the older population and the general age and golf participation rate are still rising. this makes it important to do further study on golf injury incidence, mechanism, management and other related issues, which will assist the golfing community to reduce the risk of injuries associated with golf. references 1. asch da, jedrziewski mk, christakis na. response rates to mail surveys published in medical journals. j clin epidemiol 1997; 50:1129-36. 2. australian bureau of statistics. participation in sport and physical activities australia 2002. doc. no. 4177.0. canberra, act: australian government, 2002. 3. australian golf union. agu affiliated clubs membership statistics. may 2003. pg12-19.indd 18 4/4/07 10:30:34 am sajsm vol 19 no. 1 2007 19 4. batt me. a survey of golf injuries in amateur golfers. br j sports med 1992; 26: 63-5. 5. budney dr, bellow dg. evaluation of golf club control by grip pressure measurement. in: cochran aj, ed. proceedings of the world scientific congress of golf science and golf i. st. andrews, london, 9-13 july 1990: 30-35. 6. formoso g, moja l, nonino f, et al. clinical evidence: a useful tool for promoting evidence-based practice? bmc health serv res 2003; 3:24. 7. fradkin aj, cameron, pa, gabbe bj. golf injuries–common and potentially avoidable. j sci med sport 2005; 8: 163-70. 8. gosheger g, liem d, ludwig k, greshake o, winkelmann w. injuries and overuse syndromes in golf. am j sports med 2003; 31: 438-43. 9. greenwald r. brief assessment of children’s post-traumatic symptoms: development and preliminary validation of parent and child scales. research on social work practice 1999; 9:61-75. 10. hosea tm, gatt cj. back pain in golf. clinics in sports medicine 1996; 15: 37-53. 11. hosmer dw jun., lemeshow s. applied logistic regression. new york: wiley, 1989. 12. massett ha, greenup m, ryan ce, staples da, green ns, maibach ew. public perceptions about prematurity: a national survey. am j prev med 2003; 24:120-7. 13. mccarroll, retting ac, shelbourne kd. injuries in the amateur golfer. physician and sports medicine 1990; 18: 122-6. 14. mccarroll jr, gioe tj. professional golfers and the price they pay. physician and sports medicine 1982; 10: 64-70. 15. mchardy a, pollard h, luo k. golf injuries: a review of the literature. sports med 2006; 36: 171-87. 16. mchardy a, pollard h. muscle activity during the golf swing. br j sports med 2005; 39: 799-804. 17. mchardy a, pollard h, bayley g. a comparison of the modern and classic golf swing: a clinician’s perspective. south african journal of sports medicine 2006;18:80-92. 18. mogk jp, keir pj. the effects of posture on forearm muscle loading during gripping. ergonomics 2003; 46: 956-75. 19. nicholas j, reidy m, oleske d. an epidemiologic study of injury in golfers. journal of sport rehabilitation 1998; 7: 112-21. 20. pink m, perry j, jobe fw. electromyographic analysis of the trunk in golfers. am j sports med 1993; 21: 385-8. 21. portney lg, watkins mp. foundations of clinical research: applications to practice. 2nd ed. new jersey, nj: prentice hall health, 2000: 286. 22. portney lg, watkins mp. foundations of clinical research: applications to practice. 2nd ed. new jersey, nj: prentice hall health, 2000: 327. 23. safran mr, garrett we, seaber av. the role of warm-up in muscular injury prevention. am j sports med 1988; 16: 123-9. 24. shrier i, gossal k. myths and truths of stretching; individualized recommendations for healthy muscles. physician and sports medicine 2000; 28: 57. 25. stang a, jockel kh. studies with low response proportions may be less biased than studies with high response proportions. am j epidemiol 2004; 159: 204-10. 26. strickler t, malone t, garrett we. the effects of passive warming on muscle injury. am j sports med 1990; 18: 141-5. pg12-19.indd 19 4/4/07 10:30:35 am sajsm 502.indd original research sajsm vol. 25 no. 4 2013 95 background. pain is the most common complaint for which patients seek the help of a physiotherapist. furthermore, pain has been identified as the fifth vital sign, indicating the attention with which physiotherapists should be assessing pain. previous studies have found deficits in pain knowledge among healthcare providers. poor knowledge about pain is recognised to lead to poor assessment ability, and subsequently, to poor pain management. objective. to investigate the pain knowledge of sports and orthopaedic manipulative physiotherapists in south africa (sa). methods. data were collected online by means of a demographic questionnaire and unruh’s revised pain knowledge and attitudes questionnaire (rpkaq). participants were members of the sports physiotherapy group and orthopaedic manipulative physiotherapy group of the south african society of physiotherapy. results. the mean score for the rpkaq was 65.5% (standard deviation (sd) ±8.6). only 14.45% of the physiotherapists scored ≥75%. lowest scores were obtained for the ‘assessment and measurement of pain’ (47.6%; sd ±15.6) and ‘developmental changes in pain perception’ (58.7%; sd ±20.8) sections of the rpkaq, while the highest mean score was obtained for the ‘physiological basis of pain’ section (76.8%; sd±14.6). gender, ethnicity (defined by home language), academic training and clinical experience did not contribute significantly to overall pain knowledge. conclusion. there is an inadequate level of pain knowledge among members of the sports and orthopaedic manipulative physiotherapy groups in sa, particularly in the areas of the assessment and measurement of pain, and developmental changes in pain perception. s afr j sm 2013;25(4):95-100. doi:10.7196/sajsm.502 physiotherapists’ knowledge of pain: a cross-sectional correlational study of members of the south african sports and orthopaedic manipulative special interest groups n clenzos,1 mphil; n naidoo,2 msc; r parker,2 phd 1 sas physiotherapy, stellenbosch academy of sport, stellenbosch, south africa 2 division of physiotherapy, department of health and rehabilitation sciences, university of cape town, cape town, south africa corresponding author: n clenzos (nadiaclenzos@yahoo.com) pain is defined by the international association for the study of pain (iasp) as ‘... an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage; pain is always subjective ... ’.[1] pain is recognised as the most common complaint for which individuals seek the help of a physiotherapist;[2] however, the most commonly cited reasons for mismanagement of pain are healthcare practitioners’ negative attitudes and lack of knowledge about pain.[3] pain has been identified as the fifth vital sign,[4,5] indicating the attention with which physiotherapists should be assessing pain. vital signs are measures used to assess basic body functions. the four primary functions include temperature, blood pressure, heart rate and respiratory rate.[5] pain as the fifth vital sign was initially promoted by the american pain society to elevate awareness of pain treatment among healthcare professionals. vital signs are critical; therefore, if pain was to be assessed as seriously as other vital signs, this may lead to an improved chance of adequate and optimal treatment.[6] physio therapists are accepted and involved members of the pain-management team[7] concerned with identifying possible causes of pain. all physiotherapists registered with the health professions council of south africa are considered first-line practitioners.[8] understanding the science behind nociceptive and pain neurophysiology during the clinical assessment of patients with musculoskeletal pain is crucial in determining appropriate treatment parameters.[9] physiotherapists’ clinical reasoning of pain may in fluence reasoning associated with other aspects of clinical practice, such as the planning of physical examinations, treatment and prognostication. [10] further, central sensitisation plays an important role in the pathophysiology of numerous musculoskeletal pain disorders, yet it remains unclear how physiotherapists can recognise this condition.[9] there is a paucity of evidence relating to pain knowledge and assessment ability among healthcare professionals. the implications for physiotherapy practice are that such poor knowledge is recognised to lead to poor assessment ability, and subsequently, to poor pain management. [4] a greater understanding of pain mechanisms may enable more effective treatment and management of clinical presentations of pain.[10] in south africa (sa), there is a lack of research on healthcare professionals’ knowledge of pain, particularly such knowledge among physiotherapists. the principle aim of this study was to provide baseline descriptive information regarding pain knowledge among sa sports and orthopaedic manipulative physiotherapists, particularly those treating athletes, and to explore factors which contribute to level of knowledge. 96 sajsm vol. 25 no. 4 2013 table 1. rpkaq reliability* α if deleted there is a predictable relationship between the extent of an injury and a person’s perception of pain 0.61 pain is a physiological sensation 0.62 the sensation of pain varies from individual to individual 0.62 nociception is experienced at the site of tissue damage 0.64† the physiological basis of pain is well understood 0.62 the intensity of pain is its most important quality 0.62 two people with exactly the same physical condition or trauma will have similar experiences of pain 0.62 pain is a subjective experience 0.62 the duration of pain is similar for individuals with the same pain condition 0.61 unrelieved pain contributes to the onset of chronic pain 0.62 chronic pain always has an underlying psychological cause 0.62 a person’s statement about pain should always be accepted at face value 0.62 if there is no organic basis for the pain, then the pain is psychological 0.60 psychologically caused pain can hurt as much as organically caused pain 0.62 a person receiving compensation is less likely to recover from pain 0.62 chronic pain frequently leads to depression 0.62 it is common for someone with chronic pain to feel little control over the pain 0.62 improving an individual’s coping skills is more important than determining the extent to which there may be a psychological cause of the pain 0.62 pain due to a physiological cause and pain due to a psychological cause can occur simultaneously 0.62 people with chronic pain can continue to live productive lives 0.62 a person may have severe pain, but appear calm and rational at the same time 0.62 learning to tolerate pain builds character 0.61 relief of pain is often more important to the person than treatment of the underlying condition 0.62 deliberate faking of pain is rare among people with pain 0.62 a child who is playing after surgery may have pain 0.62 children experience less pain than adults 0.59 due to the immaturity of the nervous system, newborns have little sensitivity to pain 0.58 children have a higher tolerance for pain than adults 0.59 children can have severe headaches or migraines 0.63† if children are given medication for pain, they are more likely to think that drugs will solve their problems later in life 0.61 a premature infant is able to feel pain 0.60 children who have recurrent abdominal pain are probably seeking attention or trying to escape responsibilities 0.61 elderly people tolerate more pain 0.62 it is impossible to measure pain in an individual who is unable to communicate about pain 0.61 behavioural measures of pain are reliable measures of short, sharp pain 0.62 self-report is the most meaningful measure of pain 0.62 children remember pain 0.61 a person, who is sleeping, may have significant pain 0.62 blood pressure, heart rate, respiration and sweating are good measures of postoperative pain 0.62 increasing levels of endogenous opioids can help to determine if chronic pain is due to a cause (nb: endogenous opioids are produced by the body) 0.62 pain can be reliably measured on a variety of numeric scales 0.62 continued... sajsm vol. 25 no. 4 2013 97 methods ethical approval the study was performed in accordance with the principles of the declaration of helsinki (seoul version, 2008). the study was approved by the human research ethics committee of the faculty of health sciences, university of cape town (fhs hrec ref. 312/2011). participants participants were recruited by electronic correspondence using the south african society of physiotherapy special interest group database. members of the sports physiotherapy group (spg) and/ or orthopaedic manipulative physiotherapy group (omptg) of the south african society of physiotherapy (n=1 562) were invited to participate. using the pain knowledge scores obtained by sa physiotherapy students in a previous study (68.9%)[4] with a 4% precision interval (score range 63.9 73.9%), a sample size of 272 (17.4% response rate) with a 95% confidence interval, was calculated to be adequate and targeted accordingly. instrumentation a demographic questionnaire was used to survey the characteristics of the sample. the revised pain knowledge and attitudes question naire (rpkaq) – which covers a wide base of knowledge that is appropriate for healthcare professionals, including sections on physiological, psychological, developmental, assessment/measurement, pharmacological and cognitive/behavioural aspects of pain knowledge – was adapted for the study. the section on pharmacological management of pain was excluded, as pharmacology is outside the scope of practice of sa physiotherapists. the content validity of the original pain knowledge and attitudes questionnaire (pkaq) was established by consultation with five internationally recognised experts in pain research, and a cronbach’s α of 0.65 was reported.[11] internal consistency of the adapted rpkaq used in this study was established post hoc by calculating reliability; it was shown to have an acceptable cronbach’s α of 0.62. as summarised in table 1, α-values were determined for each question and recalculated with individal items deleted to explore the contribution that each item made to the underlying construct of the subscale. the omission of items did not significantly affect the underlying construct of the questionnaire. four questions caused a slight increase in α-value when omitted, suggesting that there may have been an associated interpretation issue. however, as the increase in α-value was <0.1 in each case, the items were retained. procedure all members of the spg and omptg were informed of the purpose of the study via e-mail. the e-mail included a link to the questionnaire on survey monkey. electronic informed consent was obtained prior to providing access to the questionnaire. all data were anonymous. statistical analysis data were analysed for those who completed the full questionnaire. respondents who completed only the demographic data or did not complete the full questionnaire were excluded from the analysis. the score selected to represent an appropriate level of knowledge for the rpkaq was 75%, as this represents a first-class pass at sa universities. pain has been identified as the fifth vital sign,[4] indicating the attention with which physiotherapists should be assessing pain. vital signs are critical; therefore, 75% was regarded as a necessary score of adequate knowledge if pain is to be assessed as seriously as other vital signs. correlations between pain knowledge and gender, ethnicity, academic training and clinical experience were analysed. table 1 (continued). rpkaq reliability* α if deleted behavioural measures of pain are reliable indicators of chronic pain 0.61 asking the person ‘how do you feel?’ is usually the best way to measure pain 0.62 frequent measurement of acute pain may make the pain worse 0.61 being engaged in meaningful activity may reduce a person’s perception of pain 0.62 cognitive/behavioural methods of pain relief are more effective than pharmacological methods 0.61 relaxation is an effective method of pain relief for mild to moderate levels of pain 0.63† reinforcement of coping with pain is an important treatment intervention 0.62 a spouse, parents or other family members may exacerbate non-coping behaviours 0.62 cognitive/behavioural methods have more effect on reducing mild pain than pain which is moderate or severe 0.63† progressive relaxation (tension with relaxation) may cause more pain 0.62 it is preferable to use cognitive/behavioural methods rather than pharmacological treatments for pain relief 0.62 changing a person’s patterns of thought regarding pain may improve coping skills. 0.62 cognitive/behavioural methods may have more impact on improving coping than on reducing the intensity of pain. 0.61 rpkaq = revised pain knowledge and attitudes questionnaire. * summary for scale: cronbach’s α = 0.62. † increase in α-value. 98 sajsm vol. 25 no. 4 2013 th e demographic data and knowledge of the whole sample group were presented using descriptive statistics in the form of means ± standard deviations (sds). diff erences in levels of knowledge between two independent groups, those with adequate v. inadequate pain knowledge, were analysed using the mann-whitney u-test for numerical data and the χ2 test for categorical data. relation ships between levels of knowledge and factors that may influence knowledge were illustrated using spearman’s correlation coefficients. signifi cance was accepted at p<0.05. results a total of 207 respondents completed the full questionnaire, representing a response rate of 13.25%. descriptive characteristics the sociodemographic and professional character istics of the participants are presented in table 2. the participants were predominantly female, english-speaking, with a mean 14 years of experience as physiotherapists. the majority had experience in treating athletes and had been doing so for a mean of 12 years. pain knowledge and attitudes questionnaire th e mean rpkaq score was 66% (sd ±9). the lowest scores were obtained for the ‘assess ment and measurement’ (48%; sd ±16) and ‘developmental’ (59%; sd ±21) sections of the rpkaq. the highest scores were obtained for the ‘physiology’ (77%; sd ±15) and ‘psychology’ (73%; sd±11) sections. th e mean score for the ‘cognitive/behavioural’ section of the rpkaq was 68% (sd ±12). no signifi cant correlations were found between the total rpkaq scores and gender, home language, postgraduate qualification or experience in treating athletes. adequate pain knowledge scores only 15% of the participants had adequate scores on the rpkaq (i.e. score ≥75%). a comparison of the percentage of participants obtaining adequate scores in each of the rpkaq subsections is illustrated in fig. 1. th e only subsection in which the majority of participants obtained adequate scores was ‘physiology’, with 57% of participants receiving an adequate score (≥75%). only 4% of the participants had adequate knowledge in the ‘assessment and measurement’ section. table 2. sociodemographic characteristics of the sample (n=207) age (years), mean (±sd) (range) 38 (±10) (23 68) gender, n (%) female 184 (89) male 23 (11) home language, n (%) english 111 (54) afrikaans 79 (38) english/afrikaans 6 (3) sesotho 2 (1) siswati 1 (0.5) xitsonga 1 (0.5) dutch 1 (0.5) german 4 (2) english/italian 1 (0.5) english/portuguese 1 (0.5) postgraduate qualifi cations, n (%) professional postgraduate course 119 (57) masters 33 (16) phd 2 (9) currently in clinical practice, n (%) yes 191 (92) no 16 (8) years of clinical experience, mean (±sd) (range) 15 (±10) (1 44) experience treating athletes,* n (%) yes 193 (93) no 14 (7) number of years treating athletes, mean (±sd) (range) 12 (±11) (0 40) *athlete is defi ned as any person who is profi cient in sports and/or any other form of exercise, at any level of participation. adequate pain knowledge (≥75%) inadequate pain knowledge (<75%) % 100 90 80 70 60 50 40 30 20 10 0 o ve ra ll p ai n ph ys io lo gy ps yc ho lo gy d ev el op m en ta l a ss es sm en t a nd m ea su re m en t c og ni tiv e/ b eh av io ur al fig. 1. percentage of participants obtaining adequate and inadequate scores on the rpkaq. sajsm vol. 25 no. 4 2013 99 factors contributing to pain knowledge the analysis of variables according to adequate or inadequate pain knowledge (rpkaq ≥75%) revealed no differences in terms of gender for the total score or for any of the subsections. there were no significant differences between those with adequate v. inadequate in terms of home language. in addition, there was no difference in the pain knowledge scores between those who completed their undergraduate degree in their home language and those who completed their undergraduate degree in a second language. those who studied in their first or home language scored significantly higher (77%; sd ±14) in the ‘physiology’ section of the rpkaq than those who studied in their second language (68%; sd ±15) (u=677.00; p=0.04). furthermore, no significant differences were found between those with adequate pain knowledge and those with inadequate pain knowledge in terms of years of clinical experience or experience in treating athletes. there was a weak but significant positive correlation between the number of years since graduation and the ‘psychology’ section of the rpkaq (r=0.20; p<0.05), as well as the ‘cognitive/behavioural’ section of the rpkaq (r=0.17; p<0.05). this correlation showed that increased time since graduation corresponded with better knowledge scores for the psychological and cognitive/behavioural aspects of pain. similarly, there was a weak positive correlation between the number of years in clinical practice and the pain knowledge scores in the psychological (r=0.19; p<0.05) and cognitive/behavioural aspects of pain (r=0.17; p<0.05). furthermore, physiotherapists who were involved in lecturing scored significantly higher in the ‘physiology’ section than those who were not (84% (sd ±12) v. 75% (sd ±15), respectively; u=2 093.50; p=0.0005). the type of lecturing (undergraduate, postgraduate and/or continued education courses), however, was not significant (χ2=9.91; p=0.13). discussion physiotherapists have a central role in all aspects of pain assessment and management, particularly in the management of musculoskeletal injuries. the mean score for the rpkaq in the study sample was 65%. this is well below the score regarded as indicating adequate knowledge (≥75%). these results are concurrent with a previous sa study which also identified poor pain knowledge scores in final-year health sciences students.[4] the spread of scores across the different knowledge areas in the present study reaffirms the findings of parker et al.[4] and strong et al.,[11] who identified the areas of most knowledge to be in the physiological aspects of pain, while assessment and measurement knowledge was found to be least understood. this is one of only a few studies where attempts have been made to quantify adequate pain knowledge, classified as a minimum rpkaq score of 75%. it is of concern that 86% of the physiotherapists had inadequate scores on the rpkaq; thus indicating a poor level of pain knowledge among members of the sports and orthopaedic manipulative physiotherapy groups in sa. the significance of this is highlighted by the fact that poor knowledge of current best evidence about pain may limit efficacy of intervention,[12] leading to poor assessment and management of patients with musculoskeletal pain. [4,9] these factors represent barriers to the reconceptualisation of the problem of chronic pain.[12] despite iasp guidelines aiming to improve and standardise pain education, there is a paucity of research on the pain curriculum content in healthcare courses in an sa context. the results of the present study indicate the need for improved education in pain, with particular focus on the ‘assessment and measurement’ and ‘developmental’ aspects of pain. it is unclear whether the deficit in pain education lies at an undergraduate or postgraduate level. considering the results of the present study, where postgraduate qualification was not associated with improved scores, targeting undergraduate training may be most beneficial. the literature highlights the importance of pain education for accurate pain assessment and management, as well as the correlation between pain education and improved knowledge.[14,15] well-designed pain curricula can significantly improve pain knowledge and the associated beliefs of health professional students.[14] in this study, academic training made no significant contribution to overall pain knowledge, possibly since the majority of the physiotherapists graduated over 10 years ago. perhaps adequate education may not be associated directly with effective use of knowledge; which leads one to question the influence of other factors in healthcare professionals’ pain-management strategies. moseley[12] reported that health professionals underestimate their patients’ ability to understand the neurophysiology of pain; therefore, it is reasonable to assume that this may not form part of the theoretical basis of treatment or be included in the management approach.[12] further, clinical reasoning of pain appears to influence reasoning associated with other aspects of clinical practice such as the planning of physical examinations, treatment and prognostication.[10] previous studies have found that clinical experience influences knowledge of pain.[16,17] however, in the present study there was no significant relationship between overall pain knowledge and clinical experience. other studies concurrently show no significant correlation between postgraduate years of experience and pain knowledge.[12] interestingly, in the present study, there was a weak but significantly positive correlation between the number of years since graduation and pain knowledge related to the psychological and cognitive behavioural aspects of pain. this correlation showed that increased time since graduation was positively associated with better knowledge scores. considering that the pain education curriculum has become more salient in the past decade, one may expect to find the opposite result, i.e. for physiotherapists who trained more recently to have higher scores. this association between experience and better scores may be as a consequence of increased exposure to the psychosocial elements involved in treating athletes and/or patients with chronic pain. furthermore, perhaps with maturity and clinical experience, physiotherapists acknowledge the relevance of the psychosocial aspects of pain management. in addition, there may be better multidisciplinary interaction between older physiotherapists and psychologists. one could argue that older physiotherapists may be more flexible in accepting a biopsychosocial framework and have a wider understanding of pain beliefs and coping strategies. study limitations it is recognised that the sample size was insufficient to ensure the 95% confidence level targeted. a larger sample size may have allowed a better representation of gender, ethnicity, academic training and clinical experience of the sa physiotherapy population, and may have 100 sajsm vol. 25 no. 4 2013 influenced the results differently. in addition, uneven distribution of characteristics within the sample may have obscured the outcomes. however, despite the low response rate (13.25%) and the sample size being smaller than the targeted 272 required for a 95% confidence level, a sample of 207 gave a 90% confidence level, which is regarded as acceptable in surveys of the type described here.[16] the participants were all physiotherapists registered to practise in sa with a special interest in sports and/or orthopaedic manipulative physiotherapy. this study provides valuable information on a population group in which there is a paucity of evidence regarding pain knowledge. further limitations are found by virtue of the study design. selfadministered questionnaires are common measurement tools used to assess descriptive characteristics and obtain information from large populations. however, questionnaires are also associated with low response rates.[18] to minimise the limitations of self-administered questionnaires, a pilot study was conducted on the online demographic questionnaire and rpkaq used in the present study to assess the feasibility, accessibility, comprehension and ease of completion. however, the present study was unable to control for the disadvantages associated with self-administered questionnaires, including accuracy of mailing lists; literacy and language issues (such as dyslexia and translation); interpretation of the questions; and technical problems (possible online faults or limited access to the internet).[19] there may be sample bias in the results due to the differences in motivation between those individuals who chose to respond and those who did not respond. respondents may not have been motivated to give accurate answers, but rather to give answers that presented themselves in a favourable light. furthermore, it is identified that people who feel more confident in their knowledge are more likely to respond to questionnaires than those who feel they have insufficient knowledge.[4] if this is the case and physiotherapists with poor knowledge about pain were not motivated to respond, then the results were effectively inflated by a selection bias. the content validity of the original pkaq was established by consultation with five internationally recognised experts in pain research.[11] although the questionnaire was originally utilised over 10 years ago, the questions still hold true today. the adapted rpkaq had an acceptable cronbach’s α of 0.62. there is, however, room for revision and improvement, with the objective to develop a more recent and reliable outcome measure for pain knowledge. it is noted that cross-cultural adaptation of the questionnaire for the sa population may enhance applicability of the findings and that test-retest reliability could have been included in the pilot study to strengthen the dependability of the questionnaire. conclusion despite its limitations, the present study demonstrated that members of the sports and orthopaedic manipulative physiotherapy groups in sa may have inadequate pain knowledge. based on a minimum score of 75%, indicating adequate knowledge to assess and treat a vital sign, the physiotherapists in our sample had insufficient knowledge to ensure optimal pain assessment and management. in particular, there was a lack of knowledge in the assessment and measurement of pain as well as in the developmental aspects of pain. there was no significant contribution by academic training, clinical experience, gender or ethnicity to overall pain knowledge. the content of pain education in both undergraduate and postgraduate curricula for physiotherapists should be explored to identify the specific areas of pain education that are lacking, and to optimise the efficacy of pain education for physiotherapists treating athletes in sa. acknowledgements. we acknowledge all the physiotherapists who volunteered to participate in the study, and the south african society of physiotherapy committee, including dr ina diener (omptg nec chairperson), kerryn milella (spg secretary), ria sandenbergh (spg chairperson), magda fourie (consultant physiotherapist) and lucelle naidoo (national operations manager). references 1. iasp taxonomy. pain ter ms. http://w w w.i asp-p ain.org/am/templ ate. cfm?section=pain_definitions (accessed 4 july 2012). 2. main cj, watson pj. psychological aspects of pain. manual therapy 1999;4(4):203215. [http://dx.doi.org/10.1054/math.1999.0208] 3. scudds rj, scudds ra, simmonds mj. pain in the physical therapy (pt) curriculum: a faculty survey. physiotherapy theory and practice 2001;17(4):239-256. [http://dx.doi. org/10.1080/095939801753385744] 4. parker r, gush s, vale m, et al. pain knowledge and attitudes in final year health science students at the university of cape town. pain sa 2009;4(2):5-10. 5. elliot m, coventry a. critical care: the eight vital signs of patient monitoring. br j nurs 2012;21(10):621-625. 6. pain as the 5th vital sign toolkit. http://www.va.gov/painmanagement/docs/ toolkit.pdf (accessed 7 july 2011). 7. brown ca. treatments for patients with chronic pain: therapists’ beliefs. british journal of therapy and rehabilitation 2003;10(2):46-51. 8. south african society of physiotherapy. position paper: the first line practitioner status of physiotherapists. http://www.physiosa.org.za (accessed 27 july 2011). 9. nijs j, van houdenhove b, oostendorp r, et al. recognition of central sensitization in patients with musculoskeletal pain: application of pain neurophysiology in manual therapy practice. man ther 2010;15(2):135-141. [http://dx.doi.org/10.1016/j. math.2009.12.001] 10. smart k, doody c. the clinical reasoning of pain by experienced musculoskeletal physiotherapists. man ther 2007;12(1):40-49. [http://dx.doi.org/10.1016/j. math.2006.02.006] 11. strong j, tooth l, unruh a. knowledge about pain among newly graduated occupational therapists: relevance for curriculum development. can j occup ther 1999;66(5):221-228. [http://dx.doi.org/10.1177/000841749906600505] 12. moseley l. unravelling the barriers to reconceptualization of the problem in chronic pain: the actual and perceived ability of patients and health professionals to understand the neurophysiology. j pain 2003;4(4):184-189. [http://dx.doi. org/10.1016/s1526-5900(03)00488-7] 13. ali n, thomson d. a comparison of the knowledge of chronic pain and its management between final year physiotherapy and medical students. eur j pain 2009;13(1):38-50. [http://dx.doi.org/10.1016/j.ejpain.2008.02.005] 14. hunter j, watt-watson j, mcgillion m, et al. an interfaculty pain curriculum: lessons learned from six years experience. pain 2008;140(1):74-86. [http://dx.doi. org/10.1016/j.pain.2008.07.010] 15. moseley gl. evidence for a direct relationship between cognitive and physical change during an education intervention in people with chronic low back pain. eur j pain 2004;8(1):39-45. [http://dx.doi.org/10.1016/s1090-3801(03)00063-6] 16. enskar k, ljusegren g, berglund g, et al. attitudes to and knowledge about pain and pain management of nurses working with children with cancer: a comparative study between uk, south africa and sweden. j res nurs 2007;12(5):501-515. [http://dx.doi. org/10.1177/1744987107080455] 17. wilson b. nurses’ knowledge of pain. j clin nurs 2007;16(6):1012-1020. [http:// dx.doi.org/10.1111/j.1365-2702.2007.01692.x] 18. kelley k, clark b, brown v, et al. methodology matters. good practice in the conduct and reporting of survey research. int j qual healh care 2003;15(3):261-266. 19. bourque l, fielder e. the survey kit: how to conduct self-administered and mail surveys. 2nd ed. washington: sage publications, 2003. sasma 2015 final programme.cdr abstracts: free communications helen bayne affiliation: high performance centre, university of pretoria alteration of biomechanical risk factors for low back injury: a coaching intervention introduction: lateral flexion of the trunk after front foot contact during the bowling delivery stride is suggested to be a key mechanical component of lumbar spondylolysis aetiology in cricket fast bowlers [1]. certain aspects of the bowling action have been shown to be changeable over longterm (>2 year) coaching interventions, but it is believed that lateral flexion is difficult to change [2, 3]. the current study aimed to investigate the efficacy of a coaching intervention intended to reduce trunk lateral flexion. methods: eight fast bowlers, aged 17-19 years, underwent high-speed (120 hz) video analysis of their bowling technique. trunk lateral flexion at ball release was measured as the angle between the vertical and a line from the umbilicus to the sternal notch. five bowlers were identified as highrisk (trunk lateral flexion greater than 40° at ball release) and were assigned to a 12-week coaching intervention with the focus on reducing lateral flexion. the video analysis was repeated following the intervention period. test-retest reliability of the measurement was examined using the intraclass correlation coefficient, which was good (icc = 0.93). results: following the coaching intervention, the trunk lateral flexion angle was reduced in each bowler and there was a statistically significant difference between the preand post-intervention group mean (pre-intervention: 52° ± 5; post-intervention: 45° ± 4; t= 3.98; p < 0.05). discussion: in order to prevent injury, interventions need to target modifiable risk factors and mechanisms. the fast bowling action is a complex motor skill, and there is a commonly held belief that significant changes in technique are difficult to attain. a previous study found that the lower trunk lateral flexion angle was not improved, despite a 2-year coaching focus on this aspect of the bowling action. in the current study, trunk lateral flexion was determined by the posture of the upper trunk, and was found to be reduced following a coaching intervention. the motion of the upper trunk may be more changeable than the lower trunk. upper trunk lateral flexion has been associated with low back injury incidence in fast bowlers and this study suggests that it can be improved through coaching. daniel mark botha affiliation: department of sport and movement science, university of johannesburg the effect of hyperbaric oxygen and blood platelet injection therapy on the healing of hamstring injuries in rugby players, a case series report background: the increase in frequency and severity of hamstring injuries in rugby has been well documented. there are a number of ultrastructural and immuno-histochemical studies involving hyperbaric oxygen treatment in skeletal muscle, as well as soft tissue healing. the recovery time and complete restoration of function using traditional rehabilitation modalities requires a long duration and intensive treatment, as well as extensive off-field time. hyperbaric oxygen therapy, in conjunction with blood platelet injection therapy, serves as a valuable addition to previously known and trusted rehabilitation techniques and protocols for the healing of musculoskeletal or soft tissue injuries. objectives: the primary aim of this case report is to describe the effect on the recovery time of hamstring injuries when combining hyperbaric oxygen therapy (hbot) and platelet rich plasma (prp) injection therapy with exercise rehabilitation, compared with exercise rehabilitation alone. method: a retrospective, post-intervention data analysis was used in this case series report. the sample of injuries came from players from a premier division rugby team (23 players) who had sustained 42 hamstring injuries. data pertaining to hamstring injuries and treatment, obtained through collaboration with a professional rugby union and a south african undersea and hyperbaric medicine association (sauhma) accredited hyperbaric medicine (hbot) centre, was analysed using computer-based statistical programme for the social sciences (spss) software. the significance value was set at 5%. results: a significant decrease in the injury time of the hamstring injuries in rugby players was noted, with a 38% reduction in injury time in players with a grade-one injury, and 45.7% reduction in players with a grade-two injury. in terms of recurrent injuries, 62% of players with grade-one injuries remained uninjured after treatment, and the percentage of re-injured players with grade-two injuries was 0% after hbot, prp and physical therapy treatment. conclusion: the notion that the healing time of hamstring injuries will decrease when hbot and prp are administered in conjunction with traditional rehabilitation therapy is indicated by the data of this reported. alison brooks affiliation: university of wisconsin-madison, usa additional authors: alison brooks, timothy mcguine, scott hetzel effect of new rule limiting full contact practice on incidence of sport related concussion in high school football players purpose: to determine if the rate of sport-related concussion (src) is lower following state interscholastic athletic association mandated rule change (effective starting with 2014 season) that limited amount and duration of full contact activities during high school football practice sessions. the new rule prohibited full contact during week 1, and limited full contact to 75 min/wk during week 2 and to 60 min/wk week 3 and beyond. full contact was defined as drills or game situations that occur at game speed when full tackles are made at a competitive pace and players are taken to the ground. methods: prospective cohort study of us high school football players (grades 9-12). prior to rule change 2012 (36 schools), 2013 (18 schools) seasons, 2081 players (age = 15.9+1.2 yrs). after rule change 2014 season (26 schools), 945 players (age = 15.9 + 1.1 yrs). players provided previous concussion and demographic information by self-report. licensed athletic trainers recorded incidence and severity (median, iqr days lost) for each src. chi-square tests were used to compare incidence of src in pre-rule 2012/2013 seasons with incidence in post-rule 2014 season. wilcoxon rank sum tests were used to determine differences in severity (days lost) of src. results: total of 67 players (7.1%) sustained 70 src in 2014 compared to 206 players (9.0%) who sustained 211 src in 2012/2013 combined. overall rate of src per 1000 athletic exposures (ae) was 1.28 in 2014 compared to 1.57 in 2012/2013 (p=0.155). tackling was primary mechanism of injury for 46% of all src. the rate of src sustained overall in practice was significantly lower (p=.003) post-rule in 2014 (15 srcs, 0.33/1000ae) compared to pre-rule 2012/2013 (86 srcs, 0.76/1000ae). for 2014 season,12/15 srcs were sustained during full contact practices, compared to 82/86 srcs in 2012/2013 seasons. the rate of src in full contact practice was 0.57/1000ae in 2014 compared to 0.87/1000ae in 2012/2013 (p=0.216). there was no difference (p = 0.999) in the rate of src sustained in games pre (5.81/1000ae) and post rule (5.74/1000ae) change. there was no difference (p = 0.967) in severity of src pre (13 days lost [10-18 iqr]) and post rule (14 days lost [10.25-16 iqr]). years of football playing experience did not affect incidence of src in 2014 season (p=0.941). conclusions: the majority of src sustained in high school football practice occurred during full contact activities. the rate of src sustained in high school football practice was more than twice as high in the two seasons prior to a rule change limiting the amount and duration of full contact activities. significance of findings: limitations on contact during high school football practice may be one effective measure to reduce the incidence of src. 21 james brown affiliation: division of exercise science and sports medicine, department of human biology, faculty of health additional authors: james brown, evert verhagen, willem van mechelen, mike lambert, catherine draper coaches' and referees' perceptions of the mandatory boksmart safety course introduction: the south african rugby union (saru) launched the boksmart nationwide injury prevention program to reduce rugby-related catastrophic injuries. in january 2010, saru made the boksmart rugby safety course mandatory for all south african coaches and referees. the aim of this qualitative study was to evaluate the coaches and referees' perceptions of the implementation of boksmart, with specific focus on the mandatory safety course. methods: seven focus groups were conducted with coaches (n=43) and referees (n=7): one from each socioeconomic status (ses) group (low, mid and high) and separately for school (junior) and adult (senior) age groups. these findings were compared to those of the trainers who facilitate the mandatory safety courses. the re-aim framework was used retrospectively to categorize the findings. results: every focus group mentioned that they felt that the boksmart program was capable of reducing catastrophic injuries in players. however, there every group also mentioned also mentioned barriers to optimal implementation of the boksmart mandatory safety course prescriptions. mid/low ses coaches described infrastructure-related barriers to implementing boksmart safety course prescriptions (for e.g. not grass fields to train on), while high ses coaches felt the course to be a 'waste of their time' and that they already knew the course content. referees appeared to be incapable of policing all boksmart regulations. in general, most coaches, referees and trainers felt that the training course could be shorter and more practical (less classroom and more field-based). conclusions: the barriers identified in this study could be hindering optimal boksmart implementation. these barriers differed by role (coach/referee) and ses of the coaches (high, mid or low). understanding these barriers, as well as their determinants, is essential for boksmart implementers to optimise the program. nicholas burger affiliation: university of cape town additional authors: nicholas burger, mike i lambert, wayne viljoen, james c brown, clint readhead, sharief hendricks mechanisms and factors associated with tackle-related injuries in high-level under-18 rugby union players introduction: rugby union carries a high injury incidence and the tackle is associated with the majority of these injuries. detailed understanding of injury mechanisms is required to formulate injury prevention strategies. the aim of this study was to conduct video analysis of tackle-related injury events to identify the mechanisms and associated risk factors in high level youth rugby union players. methods: injury data and video footage were captured at the 2011-2013 under-18 craven week tournaments. based on tackle-related injury events, a representative 'control' sample of matched non-injury events in the same injured players were identified. the video footage (pre-contact, contact and post-contact) was then retrospectively analysed and coded. forty nine tackled-related injury events and 248 non-injury events were analysed. descriptive statistics (%) were reported and multinomial regression analyses (stata® version 12) are currently in progress. results: tacklers were more successful when remaining uninjured (72%) in comparison to injury events (31%), and ball-carriers were more successful (tackle break or offload) when they remained uninjured (32%) in comparison to injury events (9%). tackler were injured most often inside their own half (77%) and ball-carriers sustained most injuries in opposition half (78%). the majority of ball-carrier injuries (70%) occurred within one pass from the previous phase. the majority of injury events involved high impact forces for injured tacklers (77%) and ball-carriers (65%). ballcarriers were more likely to be injured when running fast (65%). tacklers were less likely to be injured when running slow-moderate speed (83%) and were at greater risk when ball-carriers were travelling fast (73%). a ball-carrier was less likely to be injured when they were aware of impending contact (90%), and when they exhibited moderate-strong leg-drive (65%) and fending (62%). conclusion: improving tackle technique may reduce injury risk and may result in a successful performance outcome. contact intensity and injury risk may increase when play approaches the try-line and attenuating impact forces may reduce injury rates. playing the ball wide, improving attunement/awareness, strong fending and strong leg-drive may reduce risk of injury for ball-carriers. video footage may be used to identify injury risk factors to help guide future injury intervention strategies. matthew clark affiliation: rhodes university additional authors: matthew clark, dr candice christie the effectiveness of constraints-led training on skill development in interceptive sports: a systematic review introduction: while the benefits of constraints-led training to assist in the development of technical and cognitive skill in sport appear obvious, the evidence for this type of training is not clear. therefore, a systematic review of the literature was conducted to establish the effectiveness of this approach to training. methods: four databases were searched for journal articles focused on skill acquisition within interceptive sports. a methodological and reporting quality assessment was done to determine the quality of each article. fourteen articles were selected for review. results: the results of these two quality assessments revealed poor quality scores for the majority of the studies. the effectiveness of constraintsled training on skill development could not be ascertained. key methodological structures were identified as well as aspects of methodology that should be avoided to ensure reliable results for future studies. conclusion: future research is required to determine the effectiveness of constraintsled training on interceptive sporting performance. keywords: skill acquisition, ecological dynamics approach, training, sports science, review 22 yoga coopoo affiliation: university of johannesburg additional authors: yoga coopoo, ntwanano alliance kubayi, heather morris-eyton job-related barriers encountered by football coaches in gauteng province of south africa background: football is the most played sport in the world and south africa, in particular. despite its laudable acclaim, research has shown that there is a high turnover of football coaches in the country. therefore, this study was designed to investigate work-related barriers encountered by such coaches in the gauteng province of south africa. methods: eighty six football coaches were purposively recruited to participate in this study. these coaches completed a 34-item questionnaire on the perceived hindrances to coaching which yielded a reliability coefficient of 0.952. results: results indicated that football coaches identified lack of support for women players and coaches, unfair treatment to women, inadequate salary and lack of opportunities for promotion as major barriers to their coaching. pressure to win, lack of time, unfavourable working hours and family commitments were reported as the least barriers encountered by coaches. conclusion: it is recommended that the south african football association (safa) should take cognizance of these findings and develop remedial measures to alleviate the challenges facing football coaches. the association should also ensure that all forms of discrimination against female coaches are eliminated and that their needs are well catered for. ashleigh de freitas affiliation: ukzn additional authors: ashleigh de freitas, rowena naidoo female athlete triad risk stratification in kwazulu-natal elite sprint and distance swimmers introduction: the female athlete triad (fat) is a syndrome that poses a serious threat to the health status of physically active females. it comprises of three interconnected components namely; low energy availability (with or without disordered eating) that occurs due to insufficient calorie intake in combination with high amounts of physical activity, menstrual dysfunctions defined as exercise induced menstrual dysfunction and low bone mineral density (bmd) in which the bone mineral density is weakened as a result of prolonged menstrual dysfunction. these components are linked across a continuum of healthy (optimal energy availability, eumenorrhea (a menstrual cycle of twenty eight days), and optimal bone health) to unhealthy. method(s): twenty-one national level kwazulu-natal sprint (n=11) and distance (n=10) swimmers participated in this descriptive cross-sectional study. for descriptive purposes, anthropometries measurements (weight, height, skin folds and bmi) were recorded. each participant completed three eating disorder questionnaires (eating attitude test (eat-26), body shape questionnaire (bsq-34) and a bulimic investigatory test, edinburgh (bite)), a menstrual cycle and time spent in exercise questionnaire and a self-administered bone mineral density questionnaire. a bioelectrical impedance device was used to measure full body composition. the participants also completed an online asa24 dietary recall of the previous day's food and drink intake. the criteria for the risk of the fat was determined by a positive score for all three fat components. result(s): significance will be set at a p≤ 0.05. the comparison between the different sporting disciplines revealed that sprint swimmers are more at risk (63.6%) for disordered eating compared to distance swimmers (50%). low energy availability was significantly evident in sprint swimmers with a result of 9.79 kcal.kg-1ffm.d-1 (sd 9.56) (p=.005). only six (28.57%) swimmers in total were classified as having a menstrual dysfunction. sprint swimmers showed to have a 90.9% risk of low bmd. the overall results signified that 9.5% were not at risk, 14.3% showed a low risk, 52.4% had a moderate risk and 23.8% revealed as having a high risk for the fat. conclusion: elite sprint and distance swimmers are not at risk for the fat, however, elite level sprint and distance swimmers are susceptible to the risk of fat components. jaymie donaldson affiliation: discipline of biokinetics, exercise and leisure sciences, university of kwazulu-natal additional authors: jaymie donaldson, michael ormsbee, andrew mckune the effect of protein ingestion before sleep on post exercise overnight recovery and performance in athletes introduction: recent research has shown that the provision of dietary protein before sleep leads to enhanced dietary protein digestion and absorption, thereby increasing plasma amino acid availability. in addition it has been shown that the increase in plasma amino acid availability throughout the night stimulates protein synthesis and attenuates protein breakdown, thereby improving protein balance during overnight recovery from exercise. currently there is limited information on whether the stimulation of protein synthesis results in improved performance and recovery the following day in physically active individuals. aim: to investigate the effect of protein supplementation (pro) and a placebo (pla) before sleep, post a bout of resistance exercise, on performance and recovery the following day in athletes. methods: fifteen male, resistance-trained athletes were recruited for this randomized, double blind, placebo-controlled study (pro: n=9; 24.9 ± 1.8 years; 180.2 ± 2.8 cm; 84.5 ± 3.3 kg) (pla: n=6; 28.7 ± 4.3 years; 180.1 ± 3.7 cm; 87.6 ± 5.2 kg). participants performed a strenuous 45-minute resistance exercise bout consisting of 8 sets of 8 repetitions of both squat and bench press at 75% of their calculated 1rm for each (19h15). thirty minutes prior to sleep (21h00) they consumed either 40g casein protein or placebo. venous blood samples were obtained pre exercise (t1) (18:30), immediately post (t2) (20h00), 1 hour post (t3) exercise at 21h00 and at 08h00 (t4) the next morning to measure creatine kinase (ck) and c-reactive protein (crp). peak muscle velocity and power output, maximal upper and lower body strength were measured at t1, t2 and the next morning at 08h30. perceptions of recovery and hunger were measured the next morning using visual analogue scales. results: there was a significant difference (p =.044) between the pro (m = 7.52; sd = 1.86) and pla (m = 5.27; sd = 2.01) group in terms of recovery with the pro group reporting better recovery. no group x time interactions were observed for ck, crp or muscle performance. conclusion: casein supplementation 30 minutes prior to sleep enhances the perception of recovery the next morning from a bout of strenuous resistance training in athletes. 23 david goble affiliation: rhodes university additional authors: david goble, candice jo-anne christie an investigation into the cognitive dynamics of batting: measurement of information processing in amateur cricket batsmen. introduction: batting in cricket is a demanding task, requiring physical and mental capabilities. while batting, players must offset a number of factors to ensure ultimate concentration and performance. while the bowler and the forthcoming delivery are the primary concern, external influences (crowd dynamics, field placement, information from the coaching staff and captain as well as previous performances) have a substantial affect on batting performance. in order to understand how batsmen cope with these factors, we must first understand the basic information processing capabilities required of batsmen when batting for extended periods. these have yet to be established, and as such form the basis of this investigation. methods: fifteen top order (1-5) amateur batsmen from the eastern cape province of south africa were recruited for this investigation (mean ± s: age 17 ± 0.92 years; stature 1.75 ± 0.07 m; body mass 78.29 ± 13.21 kg). participants completed a six-stage, 30-over batting simulation (batex©) interspersed with five periods (pre, post 5, 15, 25 and 30 overs) of cognitive assessment (cogstate brief test battery, melbourne australia). physical performance was assessed throughout the simulation through sprint times. results: sprint times slowed significantly (p<0.05), with the slowest times observed in stage 6. repeated shuttle running during prolonged batting significantly (p<0.05) impaired high-order cognitive performance. executive function during the groton maze-learning task was significantly impaired only post batting. further, task performance illustrated a speed accuracy trade-off where significantly (p<0.05) faster processing speed came at the expense of higher (p<0.05) error rates. in low order-tasks speed of processing and accuracy responses were unchanged. conclusion: duration of an innings is a key determinant of batting performance. further, under ideal laboratory conditions where external batting influences are reduced, it is evident that cognitive responses of batsmen deteriorate over time. therefore, future research should investigate how mitigating factors affect cognitive performance and how interventions can be introduced to improve accuracy while maintaining processing speed. further, coaches should utilise prolonged batting spells and shorter duration innings' in conjunction with shuttle running in preparation for matches. this combination may facilitate coping strategies that can be implemented during match play. janine gray affiliation: csa research consultant additional authors: janine gray, wayne derman, christopher l vaughan, paul w hodges what is the role for the local muscles in protecting the spine during fast bowling? introduction: the vertical ground reaction forces associated with fast bowling are between 4 and 7 times a bowler's body weight. the bowling reaction is a complex movement involving movement of the lumbar spine in all 3 planes of movement, very often at the extreme of range of movement. lumbar shear forces during bowl have been found to be significantly greater in bowling compared to treadmill running. the role of the deep stabilisers in counteracting these large forces is not clear. objective: to investigate the function of the local muscles in bowlers with and without lower back pain in cricket fast bowlers. methods: the function of the deep stabilisers (transversus abdominus-tra; multifidus) was assessed using electromyography in 6 adolescent fast bowlers with low back pain (lbp) and 6 fast bowlers without during 3 different tasks with decreasing stability and increasing complexity. these included a supine rotation task, a rapid limb task and fast bowling. results: during the rotation task the tra displayed an asymmetrical activation pattern. there was less tra and multifidus activity in patients with pain. the normal anticipatory pattern which was evident in fast bowlers without lbp was delayed in fast bowlers with lbp during the rapid limb task. in addition, the tra activity was again asymmetrical in both groups of bowlers. during bowling the tra on the non-dominant side exceeded 70% of the peak activity between bfi and ffi for a longer duration in bowlers with tra. however, the function of the tra on the dominant side was less before and after foot contacts in bowlers with lbp. conclusion: the tra appears to play a role in stability during rotation which is particularly relevant in sports like cricket. crickets with lbp had comparatively less activity of both multifidus and tra which demonstrates a dysfunction in the lumbar spine stability system. tania gregory affiliation: stellenbosch university additional authors: tania gregory, karen estelle welman somatosensory training improves mobility and fear of falling in individuals with mild to moderate parkinson's disease introduction: recent research has indicated that deficits in proprioception have a negative affect on postural control (pc), but that the precise contribution to postural instability in parkinson's disease (pd) remains unclear (bekkers et al., 2014). the study investigated whether an 8-week somatosensory training program (sstp) will influence mobility and fear of falling in individuals with pd. methods: thirty-seven individuals with idiopathic pd (67 ± 9 years; hoehn & yahr: 2 ± 1) were divided into either a somatosensory training group (exp; n = 24) and placebo group (pbo; n = 13). the movement disorder society unified parkinson's disease rating scale (mds-updrs), timedup-and-go (tug), as well as fall efficacy scale-international (fes-i) were assessed before and after the 8 weeks. results: a treatment effect was found in the tug (p = 0.0001), part iii (p = 0.02), total score of mds-updrs (p = 0.02) as well as in fes-i (p=0.02) for exp. the exp group improved in the tug after the intervention (p < 0.001) and showed strong tendency for improvement in part iii of mds-updrs post-intervention (p = 0.05). additionally, a significant group difference was found after the intervention for the tug (p = 0.01), with exp showing improved results compared to pbo in both instances. conclusions: the positive findings of this study provide evidence that this sstp can improve mobility and fear of falling in pd individuals. 24 sharief hendricks affiliation: university of cape town additional authors: sharief hendricks, sam o connor, wayne viljoen video analysis of concussion injury mechanism in under-18 rugby – a preliminary study introduction: understanding the mechanism of injury is necessary for the development of effective injury prevention strategies. video analysis of injuries provides valuable information on the playing situation and athlete-movement patterns, which can be used to formulate these strategies. the aim of this study was to conduct video analysis of the injury mechanisms of concussion in under-18 rugby. methods: injury reports for 18 concussion events were collected from the 2011-2013 under-18 craven week tournaments and video footage was recorded for all three years. based on the injury events, a representative 'control' sample of matched non-injury events in the same players were identified. the video was then retrospectively analysed. ten injury events (5 tackle, 4 ruck, 1 aerial collision) and 83 non-injury events were analysed. results: sixty percent of players were unaware of impending contact. for the measurement of head position upon contact, 43% had a 'down' position, 29% the 'up and forward' and 29% the 'away' position (n=7). the speed of injured tackler was observed as 'slow' in 60% of injurious tackles (n=5). in three of the four rucks in which injury occurred (75%), the concussed player was acting defensively either in the capacity of 'support' (n=2) or as the 'jackal' (n=1). conclusion: interventions aimed at improving peripheral vision, strengthening of the cervical muscles, targeted conditioning programmes to reduce the effects of fatigue, and emphasising safe and effective playing techniques have the potential to reduce the risk of sustaining a concussion. erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, additional authors: erik hohmann, tony young, ross clark, adam bryant, peter reaburn using the nintendo wii to measure balance as a predictor of functional outcome in acl reconstructed knees a novel technique introduction: the purpose of this project was to assess the relationship between single leg standing balance using the nintendo® wii™ balance board (nwbb), functional outcome measured by the hopping tests, muscle strength and the ikdc score in subjects with aclreconstructed (aclr) knees. methods: 25 acl reconstructed patients with a mean age of 29.32+9.40 years (range 17 years to 53 years) and a mean of 40.4+52.14 months since their respective operations were included. the single leg standing balance was tested using the nintendo wii (nwbb) and centre of pressure (cop) pathlengths was recorded for thirty seconds in both the reconstructed and contra-lateral leg. the nwbb was also used to measure isometric strength of both the quadriceps and hamstring muscle groups. in addition all subjects performed a singlelegged hopping, vertical jumping test and the ikdc scoring system was completed. results: statistical analysis using a linear least square regression model demonstrated that standing balance is a strong and significant predictor (p=0.03) of functional outcome. conclusion: the results of the current project clearly demonstrated a significant relationship between standing balance and functional outcome. the results highlight the need to also focus on proprioceptive rehabilitation on patients following acl reconstruction. erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, additional authors: erik hohmann, elisabeth livingstone, adam bryant, kevin tetsworth, andreas imhoff tibial acceleration profiles in young female athletes during the menstrual cycle as an indicator for dynamic stability. purpose: it is widely accepted that musculoskeletal injuries in sports are sports specific and not sex specific and raises the question as to why female athletes have a higher incidence of knee injuries in particular ruptures of the anterior cruciate ligament. tibial acceleration is one of the main indicators of dynamic stability and tibial shock attenuation. it has been shown that athletes who are able to arrest tibial acceleration faster tend to display greater knee functionality whether acl deficient or reconstructed. the purpose of this study is to investigate tibial acceleration profiles in young female athletes during the different stages of the menstrual cycle. methods: eleven females aged 16-18 years participated in this study and were compared to a male control group. female subjects were tested at each of the four phases of the menstrual cycle: menses, follicular, ovulation and luteal. on each test occasion, acceleration transients at the proximal tibia were measured whilst subjects performed an abrupt deceleration task (simulated netball landing). the male control group was recruited from the local development rugby team. results: no significant differences were found between the different phases of the menstrual cycle for peak tibial acceleration (pta; p=0.57), and time to zero tibial acceleration (tzta; p=0.59). however, there was a significant difference for time to peak tibial acceleration (tpta) between menstruation and follicular (p=0.04), menstruation and ovulation (p=0.001), menstruation and luteal phase (p=0.002), and follicular phase and ovulation (p=0.007). in the male control group, no significant between test session differences were observed for pta (p=0.48), tzta (p=0.08) and tpta (p=0.29). while there were no significant between group differences for pta (p=0.21) and tzta (p=0.48), significant between-group differences were observed for tpta (p=0.001). conclusion: the results of this project strongly suggest that serum estrogen fluctuations have an effect on tibial acceleration profiles in young female athletes during different phases of the menstrual cycle. 25 erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, additional authors: erik hohmann, kevin tetsworth, adam bryant, peter reaburn does muscle strength influence knee functionality in the acl-deficient and acl-reconstructed knee? purpose: functionality in the anterior cruciate ligament (acl)-deficient and acl-reconstructed knee is multi-factorial and no single biomechanical variable is determinant of knee functionality. the purpose of this study was to investigate the relationship between quadriceps and hamstring muscle strength and knee functionality in the acl-deficient and acl-reconstructed knee. methods: forty four acl-deficient patients with a mean age of 26.6 years were tested within 3 months of injury and 24 aclreconstructed patients with a mean age of 27.2 years were tested at 12 months after surgery. all reconstructed patients underwent surgical reconstruction within six months after acl injury using bone-patellar tendon and interference screws. the cincinnati knee rating system was used to assess knee functionality. muscle strength was assessed with the biodextm dynamometer. isokinetic concentric and eccentric peak torque (nm/kg) of the hamstring and quadriceps muscle were tested at three different speeds: 60 deg/sec, 120 deg/sec and 180 deg/sec. isometric strength was tested in 30 and 60 degrees of knee flexion. both the involved and non-involved legs were tested to calculate symmetry indices. results: the mean cincinnati score in the acl-deficient subject was 62.0±14.5 (range 36-84). the mean cincinnati score in the acl-reconstructed knee was 89.3±9.5 (range 61-100). significant relationships between knee functionality and muscle strength in the acl-deficient group were observed for knee symmetry indices (r=0.38-0.50, p=0.0001-0.05). in the acl-reconstructed group significant relationships between knee functionality were observed for isometric and isokinetic peak torque of the involved limb (r=0.46-0.71, p=0.0001-0.007). conclusion: the findings of this study strongly suggest that neither peak quadriceps or hamstring torque were correlated of knee functionality in the acl-deficient knee. however, leg symmetry indices were correlated to knee functionality. in the acl-reconstructed, knee symmetry indices were not related to knee functionality but peak quadriceps and hamstring isokinetic concentric and isometric were. erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, australia additional athors: erik hohmann, kevin tetsworth glenoid version and inclination is a risk factor for anterior shoulder dislocation introduction: whilst the contribution of both the capsule-ligamenteous structures and dynamic muscle balance to shoulder stability has been well documented, the role of the osseus anatomy of the glenoid has not been well established. the purpose of this study was to investigate glenoid version and inclination in patients with a documented anterior shoulder dislocation compared to a control group. methods: all patients presenting to the knee and shoulder clinic below the age of 50 years who underwent mri for a shoulder condition were included. version was measured on axial and inclination on t2-weighted spin-echo axial coronal images. the mr images of 66 patients with a mean age of 24.6+8.6 years with a confirmed traumatic anterior shoulder dislocation (study group) and 129 patients with a mean age of 37.6+9.5 years (control group) were evaluated. results: the mean retroversion in the study group was 3.7+4.4 degrees and 6.1+5.2 degrees in the control group. the difference between the two groups was significant (p=0.001). the mean inclination in the study group was 2.0+6.6 degrees sloping downwards and 2.5+7.2 degrees sloping upwards in the control group. the difference between the two groups was also significant (p=0.0001). conclusion: the results of this project strongly suggest that both osseous version and inclination are a risk factor for anterior shoulder dislocation. louis holtzhausen affiliation: division sport and exercise medicine, university of the free state additional authors: johan myburgh, louis holtzhausen, gert van zyl exercise prescription by south african doctors part 2: knowledge, attitudes and self-perceived competence towards exercise prescription among final year medical students introduction and aim: physical activity (pa) promotion is an integral part of preventative health care and reducing morbidity and premature mortality. many barriers exist in implementing exercise prescription into the health care paradigm, possibly including inadequate undergraduate medical training. the aim of the study was to investigate the knowledge, attitudes, and self-perceived competence towards exercise prescription, as well as own exercise habits, amongst final year medical students from two south african universities . methods: a descriptive, cross-sectional study was conducted by means of an anonymous, self-reported questionnaire. descriptive statistics was used, and correlations calculated at 95% confidence intervals. results: only 16.9% of south african medical students obtain knowledge regarding exercise prescription from their medical curriculum (24.7% from university a and 9.6% from university b). only 62% of students achieved an overall pass mark on the fundamental principles of exercise prescription. the vast majority (97.9%) of university b students do not know formal guidelines for exercise prescription and 35.1% of them are unlikely to prescribe exercise (p=0.0001), compared to 22.5% from university a. university b students feel more competent in prescribing exercise correctly than university a (23.6% vs. 15.2%). formal guidelines for exercise prescription is regarded as highly important by 57.8% of students, but only 19.3% feel highly competent in using it to prescribe exercise. a direct correlation exists between students' health habits and attitudes toward preventive counselling. only 17 % of students meet the ascm's criteria for exercise for health. conclusions: the knowledge of south african final year medical students on exercise prescription is inadequate, rendering them unlikely to prescribe exercise. minimal curricular input on exercise prescription at one university made a significant difference in knowledge and attitudes. review of curricular content is recommended to include principles of exercise prescription. the promotion of physical activity to medical students during their training years is also recommended, to contribute to their health and increased awareness of the benefits of regular exercise. 26 david lee affiliation: griffith university, griffith university centre for musculoskeletal research, menzies health institute queensland additional authors: david lee, rod barrett, richard newsham-west, michael ryan regional strain variations of the human in-vivo patellar tendon using digital image correlation (dic) introduction: in-vitro research has shown that strain variations occur within and along the fibers of the patellar tendon. consequently, it has been hypothesised that these variations may contribute to the occurrence of patellar tendinopathy and may explain the specific localised lesion that occurs with the pathology. the primary aim of this study was to apply dic to investigate the regional strain distributions within the human in-vivo patellar tendon. specifically this study assessed 1) variations in mean strain between the proximal, mid, and distal tendon regions; and 2) variations in mean strain between the deep and superficial layers of each region. methods: seven adult subjects (5 males, 2 females; age = 30.5 +/3.5 y) performed rate controlled voluntary ramped contractions to a normalised target torque over a specified rate with simultaneous collection of sagittal plane imaging of the patellar tendon and knee extensor torque using real time b-mode ultrasonography and dynamometry, respectively. ultrasound images were subsequently processed using specialized software to estimate regional strain variations within the in-vivo patellar tendon. results: mean strain along the full length of the patellar tendon was estimated at 4.68% (±1.64%) with no significant difference between deep and superficial layers (4.64% (±1.68%) vs 4.7% (±1.66%)). strain estimates were found to be highest at the proximal and mid tendon regions when compared to the distal region (7.27% (±2.64%) vs 5.84% (±2.83%) vs -1.4 (±3.79%). strain estimates for the deep tendon layer were found to be higher when compared to the superficial layer for the proximal and mid regions (7.8% (±2.81) vs 6.73% (± 2.58%) and 6.49% (±3.14%) vs 5.15% (± 2.61%). for the distal region, the superficial layer estimates were found to be higher than the posterior layer (1.41% (± 3.03%) vs -4.07% (± 4.89)). conclusion: this study shows significant regional strain variations exist within the patellar tendon during ramped isometric contractions. higher strain in the proximal deep tendon layer would suggest stress overload as an etiological factor in patellar insertional tendinopathy. strain estimates for the distal deep layer suggest that this region undergoes compression during isometric knees extension. james leitao affiliation: spine unit and pain management centre return to sport: a spine surgeon's perspective introduction: although there are isolated protocols, there are currently no clear guidelines for sports therapists following spine injury or spinal surgical interventions. both elite and regular athletes are unsure about what to expect after a back injury or spine surgery. all are keen to return to sport as soon as possible. there needs to be sensible and standardized approach to guide and rehabilitate individuals with back injury or spine surgery. the goal of any rehabilitation should be individualised depending on the diagnosis, surgical intervention, pain, time since surgery and specific sport. when to return to sport, which type of sport and the role of prehabilitation are some key questions that need to be addressed with the individual athlete. avoiding the disruption of the healing process by preventing excessive loading of the spine in all planes, in the early stages of repair, must be the goal. based on biomechanical aspects of the spinal conditions with which the athlete presents, spine surgeons normally classify spinal disorders. athletes with discogenic pain have varying lengths of recovery period and can return after a short interval of rest and rehabilitation. the risk of recurrence is low. athletes with large disc herniation's and pain should be managed conservatively initially. the risk of recurrence is higher with a broad based uncontained disc herniation. athletes with surgical intervention should have a tailored approach for return to sport. the approach should be based on structural integrity of the spine and will vary from a few weeks for endoscopic surgery to a few months for spinal fusion. summary: a multidisciplinary approach to return to sport following spine injury or surgical intervention along with graduated return to sport should be the key focus. avoiding excessive loading in all planes of motion in the early stages of healing and a significant prehabilitation is essential. physiotherapists, strength and conditioning specialist, biokinetist and sports technical coach have to play a role in an integrated manner. surgeons must share information about the surgical procedure and the stability of the spine with the patient and all therapists. 27 danielle lincoln affiliation: rowsa (rowing south africa) rehabilitation of a sa rowing athlete following serious illness background: the 24-year-old athlete began rowing at school in 2003 and joined the elite squad in 2008. he achieved gold and silver medal status at u23 world championships in 2 consecutive years. history: prior to diagnosis he presented with an 18 24 month history of recurrent upper respiratory tupper respiratory tract infections, occasional episodes of tiredness and fatigue and a slowly, progressive slight decrease in performance. clinical: the clinical examination was essentially normal. investigations: the routine bloods showed anaemia of chronic disorder and raised crp and he was investigated for chronic infection during which he was treated for h. pylori infection. as things did not settle he was investigated further with a high resolution ct scan, bone marrow biopsy, lymph node biopsy and a pet scan. he was diagnosed with hodgkins lymphoma stage iv with involvement of the bone marrow and spleen. treatment: he was treated with escalated beacopp – bleomycin, etoposide, adriamycin, cyclophosphamide, oncovin, prednisone and procarbazine. the regime was chosen for his disease status as well as the side effect profile, which had advantages for an athlete. the pet scan was clear after 2 cycles and after completion of the full regime. complications during treatment pneumonia following bone marrow suppression return to training points of concern 1. bone marrow suppression 2. drug side effects 1. bleomycin 2. adriamycin 3. prednisone 4. weight gain 5. reintegration into the programme considering the athlete had the mind of an athlete but the body of a post chemotherapy patient return to full training was graded. restrictions were placed on his training workload and a low intensity of work was enforced with a heart rate cap and a reduced length of session. running was avoided until an optimum weight was achieved. he was given mental support during this period, as there was a high level of frustration. after 6 weeks of low-grade training he was fully assessed for signs of chemotherapy toxicity with a full physical examination, a full blood screen, an extensive cardiac assessment, which included an echocardiogram and stress ecg, as well as lung function tests. there is ongoing assessment for signs of disease relapse and although the risk 3%), monitoring will be close for the next 5 years. outcome: he has returned to full training and is currently working towards the world championships james macdonald affiliation: nationwide children's hospital, columbus, oh usa additional authors: james macdonald, mitchell selhorst, anastasia fischer, reno ravindran, richard rodenberg, eric peters, kristine graft, eric welder prolonged rest versus early physical therapy in patients with active spondylolysis introduction: spondylolysis is a stress fracture most commonly occurring in the lumbar spine. this injury is common in adolescent athletes, accounting for as much as 40% of all low back pain in this population. currently, there is no evidence to guide physicians on when to make a safe referral to physical therapy [pt] for these patients. there were two primary objectives of this study: (1) to determine if the amount of time prior to referral to pt affects the time to make a full return to activity for patients with an acute spondylolysis (2) to assess the safety of an early referral to pt compared with a longer rest period prior to pt in patients with an acute spondylolysis. methods: this was a retrospective study which consisted of the review of each patient's medical chart and lumbar imaging. participants: one hundred and ninety-six patients with an acute spondylolysis injury met the inclusion criteria during the pre-selected review period. patients were sub-grouped into 2 groups by physician referral patterns: an aggressive referral to pt group (< 10 weeks) and a conservative referral to pt group (> 10 weeks). safety was assessed by calculating the number of adverse reactions experienced in each group during the course of treatment. data analysis: mann-whitney u tests were used to analyze the first study objective. relative risk of an adverse reaction was calculated to assess the second study objective. results: median days to a full return to sport for aggressive pt referral group (115.5 days iqr 50.5) and conservative pt referral (140.0 days iqr 40.3) was significantly different (p = 0.003). a total of 11 patients had documented adverse reactions during the course of treatment for acute spondylolysis. although there was a higher percentage of patients who experienced an adverse reaction in the conservative referral to pt group, this difference was not statistically significant (p = 0.509). conclusions: the results of this retrospective study show that patients of physicians who referred to physical therapy sooner returned to sport more quickly without an increased risk of adverse reaction 28 akshai mansingh affiliation: university of the west indies management dilemmas in treating cricket injuries introduction: injuries in cricket players are well documented as to which areas of the body that are injured, what type of injury is more common and which activity or what type of player sustains them. however many injuries that prove to be diagnostic challenges, or are not often seen and thus missed. additionally, there are injuries whose management may be affected by the state of the game, the stage of a series or the role of the player. this paper presents a series of challenging cases to highlight difficult management decisions that need to be taken. methods: cases that were diagnostic dilemmas and management challenges in west indies cricket were selected from the injuries treated by the author these include: a rare shoulder injury, which provided diagnostic challenges a head injury was a management challenge finger injuries which were interesting and could have been managed in different ways knee injury which had negative mri findings but required surgery. the format of the presentation is preferably interactive, in which case histories will be presented and the audience will be asked to participate in discussion before the final management is revealed. results: the results of each case will be discussed with the audience aiming to focus on the cases in particular, but give an insight into management decisions that are often required in elite cricket. conclusion: this paper will highlight injuries that are either common in cricket but pose difficult management considerations and could have many different ways of treating. it will also present some rare injuries that are often missed. akshai mansingh affiliation: university of the west indies additional authors: akshai mansingh, christopher clark, isabel moore, craig ranson, changing trends of injuries in international cricket; reviewing 10 years of injuries in west indies cricket introduction: only australia and west indies have reported a decade of longitudinal injury data. during this time there have been variations in the types of injuries seen, as well as time lost due to injury, prevalence and incidence of injury. this paper looks at injuries sustained in west indies cricket over ten years and identifies changing trends and how these have affected the game. methods: prospective injury surveillance of players selected for the west indies cricket team from 2005 to 2014 was collected based on consensus methods. additionally both time-loss (tl) injuries (player unavailable for match selection) and non time-loss (ntl) injuries (requiring medical attention but player available for selection) were included. results: there were 404 injuries [212 ntl injuries; 192 tl injuries] by 79 players, at 1.21 injuries/100 days (0.63 ntl; 0.57 tl). incidence of ntl injuries was higher than tl injuries during training (0.28 vs. 022/100 days), but similar during matches (0.29/100 days). more ntl injuries (32%) were chronic compared to tl injuries (15%). mild injuries (<3 days lost) had the highest incidence (0.23/100 days). fielding resulted in the most injuries. the hand, lower back, shoulder and knee accounted for 42% of injuries. there were more acute injuries sustained but required less time lost from the game. trends changed from chronic injuries requiring long periods out of the game (stress fractures of the back) a decade ago, to soft tissue strains with less than a week out of the game now. conclusion: there was a low injury incidence over a decade, but a high proportion of tl injuries compared to other studies. fielding resulted in the most injuries, which may require attention to technique. less time is lost from play due to the change in types of injuries, better medical support and quicker detection of injury. as most ntl injuries took place during training, modifications in training methods may need to be considered. prevention strategies for hamstring strain injuries should be implemented focusing on known risk factors, such as muscle strength deficiencies, whereas for ankle injuries, being able to manage on-going ntl injuries should be targeted. robroy martin affiliation: duquesne university additional authors: robroy martin, ben kivlan, hal martin a cadaveric study of the dynamic internal rotation impingement (diri) and dynamic external rotation impingement (dexri) tests purpose: labral pathology of the hip joint is commonly associated with an abnormal abutment of the femoral neck to the acetabular labrum. there have been many clinical tests developed to help determine the presence of labral pathology with limited evidence of validity to support their use. the dynamic internal rotation impingement (diri) and dynamic external rotation impingement (dexri) tests were proposed by martin to comprehensively assess all zones of the labrum for potential pathology due to femoroacetabular impingement. the purpose of this study was to assess the validity of the diri and dexri tests by describing the point of contact of the femoral neck relative to specific zones of the acetabular labrum in a cadaveric study. subjects: 26 hips from 14 embalmed cadavers (7 male; 7 female) with a lifespan ranging between 51-95 years were used for this study. methods: the pelvic region of each cadaver was skeletonized and the labrum marked into 5 geographic zones according to ilizaliturri as follows: zone 1 – anterior-inferior, zone 2 – anterior-superior, zone 3 – superior, zone 4 – posterior-superior, zone 5 – posterior-inferior. from a neutral anatomical position the diri test was performed by moving the femur through a full arc of flexion, adduction and internal rotation while maintaining contact of the femoral neck to the labrum. from position of maximum flexion the dexri was performed by moving the femur through a full arc of extension, abduction, and external rotation while maintaining contact of the femoral neck to the labrum. when the femoral neck made contact with each of the 5 labral zones the position of hip flexion was recorded to describe the arc of motion in the sagittal plane in which the diri and dexri tests were in contact with each specific zone of the labrum. results: the diri test made contact to zones 1-3. contact with the anterior-inferior labrum (zone 1) occurred in less than 57° of hip flexion, while contact with the anterior-superior labrum (zone 2) occurred between 57°–101°. zone 3 was contacted in a maximally flexed position. the dexri test made contact to zones 3-5. contact with the posterior-superior portion (zone 4) of the labrum occurred between 106°-15° flexion. the posteriorinferior portion (zone 5) of the labrum contacted the femoral neck as the hip joint was moved towards midline through an arc of 15-47° flexion. conclusion: the diri and dexri tests may be used to discriminate the location of labral pathology from anterior-inferior (zone 1) to posteriorinferior (zone 5) positions. clinical relevance: noting the position of hip flexion in which pain reproduction occurs during the diri and dexri tests may help to identify the specific zone(s) of labral pathology. 29 candice martin affiliation: department of physiotherapy, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand additional authors: candice martin, benita olivier the functional movement screen in the prediction of injury of high school cricket pace bowlers introduction: to ensure young cricketers remain injury free all fitness and medical staff should identify risk factors and develop preventative strategies. the functional movement screen (fms) has been developed as a pre-participation screening tool to assess the quality of an athlete's fundamental movement patterns, identify asymmetries and limitations and establish the risk of sustaining an injury. a score of 14 or less have been found to predict injury among various sport groups. no documented research confirming the predictive validity of the fms among cricketers could be found. objective: to determine if pre-season fms score is a valid predictor of inseason injury among adolescent pace bowlers. methods: this is a prospective observational quantitative study. male adolescent pace bowlers (n=27) who were injury free at the start of the season. bowlers performed the seven fms movements and were scored according to the scoring criteria as set out by the authors of the fms. injury incidence were monitored by bowlers completing the standardised self-administered questionnaires pre-season, in-season (monthly) and postseason. the independent student t-test and fisher's exact tests were used to compare the fms scores of the injured and non-injured bowlers as well as the injured and non-injured bowlers that scored ≤ 14 with significance set at p ≤ 0.05. results: the mean fms score for the sample was 16.44 (±2.41). the non-injured group (16.55±2.57) score slightly higher than the injured (16.1±2.07) group but there was no significant difference between the groups. there was also no significant difference between injured and noninjured bowlers who scored ≤14. a total fms score of 14 does not provide the sensitivity (0.2) needed to assess injury risk among adolescent pace bowlers and no other accurate cut-off score could be calculated. conclusion: pre-season observed total fms score is a poor predictor of in-season injury among adolescent pace bowlers. more research should be conducted to determine if a specific fms test or asymmetry is a more valid predictor of injury. crosby mulungwa affiliation: division sport and exercise medicine, university of the free state additional authors: crosby mulungwa, louis holtzhausen the use of traditional medicine and rituals in professional soccer in south africa introduction and aim: traditional medicine(tm) and traditional rituals (tr) are anecdotally widely used in soccer in south africa. there is no scientific information on content of substances, efficacy, possible adverse effects, or anti-doping status of tm and tr in sport in south africa. the aim of the study was to investigate the types, indications and beliefs regarding tm and tr in south african professional soccer as baseline data for further investigation (ethics clearance ecufs 56/2012). methodology: a descriptive study was conducted, with qualitative and quantitative components. the study population was selected using purposive sampling because of the rarity of people willing to divulge information on this topic. five former south african professional soccer players were interviewed using a semi-structured interview guide. descriptive data was extracted, categorised and tabulated. results: the use of tm and tr was confirmed among south african professional soccer players. a list of tm and tr was identified. the main indications for tm and tr use are injury and illness management, performance enhancement and protection. the perceived efficacies of tm versus western medicine and of tm or tr for team success are equivocal. secrecy about the use of tm and tr complicated research on this topic. conclusion: the common use, types, their indications and beliefs about tm and tr in south african professional soccer were recorded for the first time. an attempt was made to contextualise tm and tr use in soccer. there is insufficient scientific evidence or knowledge on efficacy, safety and legality of tm and tr in south africa for healthcare workers to recommend it to athletes. further scientific and socio-cultural investigation is strongly recommended. takalani clearance muluvhu affiliation: hpcsa and basa additional authors: takalani clearance muluvhu, makama andries monyeki, meriam mohlala, gert strydom physical activity and selected health risk factors profiles among local government employees in vhembe district, limpopo province of south africa. background: research studies identify physical inactivity as a global health concern associated with non-communicable diseases of lifestyle affecting people from different walks of life. the purpose of this study was two-fold: to determine the prevalence of physical activity and risk factors of chronic diseases among local government employees in the vhembe district, and to investigate the relationship between physical activity and risk factors of chronic diseases in the above-mentioned population. methods: a cross-sectional study design on an available sample of 540 (men=253 and women=287) local government employees in the vhembe district in limpopo province participated in this study. a standardised physical activity questionnaire was used to determine the physical activity index (pai) of the participants; and clinical measures of body mass index (bmi), waist circumference (wc) and blood pressure (bp) were assessed. results: the results show that 53% of the employees do not participate in physical activity, with a higher percentage in women (49%) compared to men (47%). additionally the results show the presence of both overweight and obesity (21% and 44%), with women (23%) accounted for a higher percentage compared to the men (21%). finally, the results showed that physical inactivity was positively associated with all measures of bmi, wc and blood pressure (sbp and dbp), with a significant (p≤0.05) association with bmi. conclusions: it can be concluded that 53% of the 540 employees do not participate in physical activity and had a high percentage of obesity, especially the women. the physical activity index correlated with all measures of body mass index, waist circumference, and blood pressure, and was significantly associated with body mass index. keywords: physical activity, health risk, local government employees, overweight 30 natalia neophytou affiliation: centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa additional authors: natalia neophytou, kerith d. aginsky, caitlin tracey posture and isokinetic shoulder strength in female, water polo players background: water polo players are overhead athletes, presenting with shoulder muscular imbalances between the internal rotators (ir) and external rotators (er) which may lead to changes in posture and increase predisposition to injury. objective: to assess posture and isokinetic shoulder strength of female, club level, water polo players. methods: a descriptive study assessing posture and isokinetic strength of the ir and er shoulder muscles in 15 female, club level, south african water polo players (age: 21.3 ± 1.5 years). posture was assessed using a posture grid. isokinetic shoulder rotator muscle strength was tested over 5 repetitions concentrically and eccentrically at 60°/sec using a biodex isokinetic dynamometer system 3. the bilateral, reciprocal and functional (dcr) ratios were calculated. results: typical posture included a forward head, rounded shoulder, thoracic kyphosis, an elevated non-dominant shoulder, mild scapula winging, lumbar lordosis and an anterior pelvic tilt. the mean concentric reciprocal ratios for the dominant (52.2 ± 7.1%) and non-dominant (51.9 ± 6.5%) sides indicated some er muscle weakness. however, the mean concentric (ir: 8.8 ± 10.7% and er: 10.4 ± 6.3%) and eccentric (ir: 6.1 ± 10.4% and er: 4.8 ± 30.3%) bilateral ratios were within normal limits as were the eccentric reciprocal ratios (d: 69.6 ± 16.1% and nd: 67.3 ± 10.9%) and the dcr values (d: 0.75 ± 0.2 and nd: 0.75 ± 0.1). conclusion: there is a trend for these female water polo players to have rounded shoulders and forward head postures as well as er muscle strength weakness, this combination could predispose the athletes to shoulder injury. kim nolte affiliation: university of pretoria additional authors: kim nolte, sasha burgoyne, heinrich nolte, julia van der meulen, lizelle fletcher the effectiveness of a range of sports bras in reducing breast displacement during incremental treadmill running and two-step star jumping introduction: the primary aim of the study was to investigate the effectiveness of a range of sports bras in reducing multi-planar breast displacement during incremental treadmill running and a two-step star jump. a secondary aim was to assess the relationship between perceptual bra comfort, bra fit and breast pain and measured breast displacement. methods: seventeen females (mean age 22 years, range 18 – 31 years) with bra cup sizes b to c volunteered to take part in the study. participants were assessed in the biomechanics laboratory of ergonomics technologies on 20 – 24 august 2012). three dimensional breast movements were determined for six randomly assigned breast support levels during incremental treadmill running and two-step star jumping. participants completed a perceptual questionnaire rating bra comfort, bra fit and breast pain. results: not all the bras significantly reduced resultant breast movement compared to a control condition. perceptual ratings of bra fit and bra comfort were stronger and more reliable predictors of breast pain in our group of relatively small breasted participants. conclusion: therefore it is apparent that resultant breast movement and the reduction of such movement is a multifaceted function of breast size, bra design and movement/activity type. the variance in bra performance at different treadmill running speeds highlights this fact and indicates that sports bras should be carefully selected to best suit the activity and breast size of the user. habib noorbhai affiliation: cape peninsula university of technology additional authors: habib noorbhai, timothy noakes a qualitative and biomechanical analysis of backlift batting techniques among skilled, semi-skilled and unskilled cricket batsmen introduction: one of the first principles of cricket batsmanship that is coached from a young age is to play with a straight bat. this requires the bat to be lifted directly back towards the stumps with the elbow “up”, pointing in the direction of the ball's trajectory. limited studies to date have examined whether top international skilled cricketers (sc) actually use this traditionally described technique. no study has yet examined whether there are differences in the backlift and batting techniques of semi-skilled cricketers (ssc) and unskilled cricketers (uc). methods: accordingly, we performed a descriptive, observational study of the backlift technique adopted by 65 of the most successful sc of all time based on their career averages, strike rate and runs scored. the batsmen were divided into two groups depending on whether they played the game, before or after 1954 and which described this backlift technique as the ideal. this was due to the first mcc coaching manual produced in 1954. we also investigated two study samples of ssc (comprised of both adolescent (n = 30) and amateur (n = 10) cricketers) and uc (comprised of only the young calypso cricketers (n = 40)). various types of deliveries were bowled to the participants utilising a bowling machine. biomechanical and video analysis were performed on all three participant groups utilizing kinovea. classifiers were utilised to identify the type of batting technique employed by all groups of batsmen. results: surprisingly, more than 70% of sc did not adopt the traditionally taught technique. instead they adopted a more looped action in which the initial movement of the bat was in the direction of the slips, and in extreme cases it was either towards the gulley/point region or having the face of the bat directed towards the off-side. more than 70% of uc adopted the lateral backlift batting technique whereas more than 70% of ssc adopted the straight backlift batting technique. players begin to start adopting either the lateral or straight backlift batting technique around the age of 11 years. cricketers who have a lateral angle of the backlift of more than 50o have a better chance of hitting the ball with better timing and power. conclusion and coaching implications: most coaching instruction today allows the backlift to be taken to first or second slip or have the bat face towards the stumps but not in the direction of point nor as part of a looped action. this suggests that traditionally taught batting coaching techniques may hinder rather than enhance future cricketing performance. if such players are not coached, they automatically hit the ball using a lateral technique which indirectly suggests that early coaching emphasising traditional techniques could be disadvantageous to the young cricketer. future research is required to evaluate the coaching methods of the backlift batting techniques taught by coaches at various levels in most icc countries. key words: cricket batting, backlift batting techniques, biomechanics, qualitative, skilled, semi-skilled, unskilled 31 sarah j. moss affiliation: physical activity, sport and recreation focus area, north-west university, potchefstroom school of health and sport sciences, faculty of science, health, education and engineering, university of the sunshine coast, australia additional authors: sarah j. moss, s.o. onagbiye, m. cameron managing non-communicable diseases in an african community: effects, compliance, and barriers to participation in a four-week exercise intervention. introduction: to determine the compliance, barriers, and effects of participation in a four-week exercise intervention to reduce risk factors for ncds among setswana-speaking community-dwelling potchefstroom adults from a low resourced area of south africa. methods: an exercise program and associated pre-post test were performed by 76 participants (men, n= 26 and women, n= 50) aged 35 to 65 years. baseline and end tests included height, weight, hip and waist circumference, heart rate, blood pressure, glucose, cholesterol, quality of life, and cardiorespiratory fitness measurements. the intervention consisted of three days/week combined aerobic and resistance exercise at an intensity of 70% hrr as determined at baseline. compliance and barriers to participation were determined post-intervention by means of attendance registers and interviews. ancova with adjustment for pre-test was performed for all repeated variables. the cronbach's alpha coefficients for exercise benefits were 0.81 and for barriers 0.84. results: of the 26 men (40.8±5.45 years) and 50 women (43.6 ± 7.8 years) recruited, 54 completed the intervention (71% compliance). the fourweek aerobic exercise intervention significantly reduced body mass, rpe and mcs in men, and body mass, bmi, vo2max, rpe, glucose, pcs and mcs in women. participants reported that the exercise milieu as a major barrier to exercise compliance while the interviews reported lack of time. conclusion: a one month exercise intervention elucidated positive changes in risk factors for ncds in a low-resource community. a drop-out rate of 29 % in this study is consistent with other exercise intervention trials. exploration of the reported barriers may be useful for planning to increase compliance with future programs. keywords: physical activity intervention, cardiorespiratory fitness, quality of life, non-communicable diseases, adults, setswana jessie turner pearson affiliation: division of exercise science and sports medicine, university of cape town additional authors: jessie turner pearson, lisa micklesfield, estelle lambert a formative assessment of physical activity levels in pregnant women presenting at two public health clinics in cape town, south africa background: it has been proposed that physical activity pre-pregnancy, during pregnancy and post-partum reduces the risk of both the mother and the child developing obesity and its co-morbidities. little is known about the physical activity patterns of pregnant south african women, while it is known that overweight and obesity are prevalent amongst south african women. the aim of this study was to describe the physical activity and sedentary behaviour patterns of pregnant women presenting at two public health clinics in cape town, as well as the barriers and facilitators associated with physical activity during pregnancy. methods: forty women between 18 and 35 years of age (mean: 27±4.8 yrs) and 12 and 25 weeks gestation (mean: 17±3.5 wks) were included. the global physical activity questionnaire (gpaq) was used to obtain data on self-reported physical activity and information on socio-economic status, sedentary time, knowledge, attitudes and beliefs about exercise during pregnancy, and self-efficacy related to exercising while pregnant was obtained via questionnaire. results: the sample was divided into active (n=26) and inactive (n=14) groups according to gpaq guidelines. the only significant sociodemographic difference was that a greater proportion of women who had attended tertiary education than the active group (30% vs. 19%; p=0.015). for the whole sample, majority of pa (9%) was walking for transport with only 30% of the women reporting leisure time activity and 12.5% participating in vigorous pa. the inactive group spent significantly more time sitting than the active group (13.0±3.1 vs. 9.1±3.7 hrs/day, p=0.004), and the total amount of sedentary time (including sitting watching t.v., using the computer, travelling, eating or reading, and sleeping during the day) was significantly greater for the inactive group than the active group (14.9±4.0 vs. 10.3±4.2 hrs/day, p=0.003). barriers to physical activity included knee, back and abdominal pain (93%), being too tired to exercise (63%), not having time to exercise (55%), living in an unsafe neighbourhood (40%). facilitators of exercise during pregnancy included someone to exercise with (88%), a specialised exercise programme for pregnant women (88%), somewhere to exercise (45%) and access to information about why exercise is important (45%). walking was identified as the most popular mode of exercise (75%), followed by an exercise programme at home (60%), yoga (50%) and exercises at the community hall (48%), while aerobics was the least popular choice (35%). conclusions: although the majority of the women in this study were classified as active, our study showed low levels of leisure time activity and high levels of sedentary behaviour. thus, it is apparent that there is a need for an intervention which will educate women on the benefits of physical activity for them and their baby not only during pregnancy, but also throughout their lifetime. nivash rugbeer affiliation: department of sport, rehabilitation and dental science, tshwane university of technology, pretoria. additional authors: nivash rugbeer, serela ramklass, johan van heerden effect of group exercise frequency on health related quality of life in older persons residing in institutionalised care facilities background: worldwide, the proportion of older persons aged 60 years and older is increasing. the elderly within institutionalised setting are often neglected, with the probability of disease and disability being highly prevalent. increasing age and visceral fat coupled with a lack of structured exercise results in inflammatory and pro-inflammatory processes, contributing to the deterioration of physical and physiological functioning. health related quality of life (hrqol) in the context of the elderly is defined as their functional status and independence in engaging in activities of daily living. little is known about the effect of group based exercise frequency on hrqol among the elderly residing in aged care homes within the ethekwini central business district (cbd). the study aimed to determine the effect of group exercises 2x/week vs 3x/week on health related quality of life of older persons residing in age care homes in the ethekwini cbd. methods: a quasi-experimental design was used to compare the effect of a 12 week group exercise programme on two groups of participantoups of participants using pre-test and post-test procedures. a total of 100 participants were selected from five aged care homes. twenty participants from each of the five facilities were randomly selected through convenient sampling. admittance to the group was based on the outcome of a medical assessment by a sports physician. from the 20 participants, ten participants were randomly assigned to group a (experimental) and 10 in group b (observed group). group a exercise three times a week and group b exercise two times a week for 12 weeks. the medical outcomes study 36-item short-form health survey (sf-36) was used pre and post exercise to determine effect of intervention on health related quality of life. results: results showed a significant difference in social functioning (mean participant difference (mpd) = 13.35, p = 0.00), vitality (mpd = 7.55, p = 0.00) and mental health (mpd = 5.11, p = 0.03) post training thrice a week. there was a significant difference in social function post training twice a week (mpd = 12.15, p = 0.02). improvements in mental component summary scale (p = 0.03) post training thrice (mpd = 6.67, p = 0.00) and twice (mpd = 3.68, p = 0.03) a week was also noted. conclusion: elevated vitality levels, mental and social health benefits can be obtained irrespective of group exercise frequency 2x/week or 3x/week. this may assist the elderly in preserving independence and health within long term care facilities. 32 bennett ryan affiliation: rhodes university the efficacy of a community based soccer-specific hamstring intervention in black amateur south african players introduction: hamstring injury prevalence in soccer remains a major concern. research in this context has focused on european populations with little attention given to other ethnic groups. the compatibility and applicability of such research to the south african context may be minimal due to fundamental differences in physical characteristics, as well as complexities with regards to implementation. the aim of this investigation was therefore twofold. 1) identify the lower extremity strength profile of black amateur south african players, and 2) assess the efficacy of a community based intervention through the use of the nordic hamstring exercise. methods: 19 male black eastern cape amateur players participated in a 12 week rct (9 = control, 10 = intervention). all participants completed regular training, while the intervention group, in addition, performed the nordic hamstring exercise. the incremental intervention design was taken from mjolsnes (2004). concentric and eccentric isokinetic strength evaluations were performed pre and post intervention, for knee flexors and extensors, at speeds of 60 and 180°.s-1. results: at 60°.s-1 and 180°.s-1, concentric quadriceps peak torque (pt) showed no significant difference between the intervention and control groups (p=0.957 and p=0.3141). eccentric hamstring pt indicated a significant improvement at 60°.s-1 (p=0.004) in the intervention group, with no significant changes at 180°.s-1 (p=0.1477). with regards to the functional ratio (ecch:conq), an interaction effect between group and time was found at 60°.s-1 (p=0.0148), while no changes were found between the control and intervention group at 180°.s-1 (p=0.495). conclusion: findings indicate that the intervention was partially successful. while the intervention resulted in improvements at 60°.s-1, these changes were not evident at the more functional velocity of 180°.s-1. it can be concluded that community based programs within sa have the potential to be effective; however, there are many barriers to implementation, including, language, ethnic and cultural differences, while a lack of resources and infrastructure play a significant role in a lack of development. more research of this nature is required to provide scientific support for structures and guidelines at an amateur level in sa, to ensure the efficacy of internationally successful interventions such as the nordic exercise. marlene schoeman affiliation: university of the free state additional authors: louis holtzhausen, rudi de wet, marlene schoeman clinical, haematological and biochemical characteristics of south african gold-miners presenting with exercise-associated muscle cramps, part 2: results and discussion introduction: the pathogenesis of exercise-associated muscle cramps (eamc) in mine-workers and other exercising populations is not clear. the aims of the study were to describe clinical, biochemical and haematological variables in gold miners with eamc. methodology: a retrospective descriptive study of the data of underground mine workers who presented with eamc over 18 months in a south african gold mine (cra group) was compared with a control group of similar workers without eamc from which data were collected before (conpre) and after (conpost) 8 hour shifts. results: there were 450 cases of eamc in a population of 18430 mine workers over an 18-month period (2.5%). markers which were significantly different in the cra group compared to the conpost group were signs of dehydration (increased haematocrit and haemoglobin), muscle fatigue (elevated ck), muscle damage (elevated myoglobin), inflammation (elevated total white cell and lymphocyte count), elevated urea and creatinine, increased body temperature and lower fluid intake. the control group were wellto slightly over hydrated, with progressive muscle injury (increased ck levels, but no increase in myoglobin) and well maintained kidney function during a working week. conclusion: eamc is associated with elevated inflammatory markers, dehydration and haemoconcentration, reduced absolute serum sodium and chloride levels, elevated creatinine and protein levels, and muscle damage (myoglobin). this study is the first to present a comprehensive profile of a population with eamc, compared to a control group. the interpretation of these results should be done cautiously. further investigation into the pathogenesis of eamc will be guided by these results. instead of compartmentalised theories, eamc seems to occur in a collective set of systemic and local contributing factors. marlene schoeman affiliation: sport and exercise medicine, university of the free state additional authors: marlene schoeman, ceri diss, siobhan strike jump landings in lower limb amputees: mechanical considerations for prehabilitation introduction: jumping is a fundamental movement in many recreational sports and terminates in landing. jump landing is a common cause for acute injury and osteoarthritis (oa) which raise concerns for lower limb amputees who are encouraged to participate in recreational sport yet may be compromised to perform the jump landing safely due to the loss of the most distal joint and their predisposition to oa. the aims of this study were to investigate the loading experienced by transtibial amputees (ttas) in vertical jump landings and explore compensatory mechanisms in controlling their downward momentum and attenuate the shock during landing to inform prehabilitation. methods: six unilateral ttas and ten able-bodied (ab) participants completed 10 maximal effort bilateral vertical jumps of which the highest jump was analysed. ttas had to be at least 1 year post-amputation with no secondary pathology. the single jump with the greatest vertical position of the centre of mass in each situation was used for analysis. data were collected using two kistler force platforms synchronized with a 9-camera vicon motion analysis system. a mann-whitney u test was used to assess bilateral differences and differences between the tta and ab participants. results: significantly larger (p=0.041) impact forces (25.25±4.89n.kg-1) were experienced by the ttas on the intact compared to the prosthetic side. similar impact forces to the ab participants were experienced despite landing from significantly lower (p=0.000) jump heights. the ttas performed a quasi-unilateral landing onto the intact limb, resulting mainly from the incapacity of the prosthetic ankle to plantarflex and active strategies to increase residual knee and hip flexion prior to touch-down. loading rates onto the prosthetic side were significantly higher compared to both the intact side (p=0.026) and ab participants (p=0.000) due to reduced prosthetic ankle, knee and hip roms, resulting in reduced extensor moments and negative work. the tta landing from the greatest height (similar to ab participants) experienced the smallest impact forces through a fairly symmetrical engagement of both limbs and going through large knee and hip roms. conclusion: uninformed landing strategies employed by the ttas pointed to avoidances to engage the prosthetic limb in the landing which exposed the intact limb to large impact forces which may lead to degenerative disease over the long term. attempts to keep the residual knee joint erect resulted in inadequate roms over which to generate extensor moments and produce negative work to dissipate the landing shock. landing with an extended knee evoked large loading rates which may increase acute injury risks and cause residual skin breakdown if repetitive jumping were to occur. the results imply that safer landing techniques can (and should) be taught during prehabilitation. 33 marlene schoeman affiliation: division sport and exercise medicine, university of the free state additional authors: marius roos, marlene schoeman, louis holtzhausen, gina joubert exercise prescription by south african doctors part 1: knowledge, practice and attitudes among south african doctors4 introduction: physical inactivity is the fourth leading cause of death worldwide. south africans have low physical activity (pa) levels which increase the morbidity and mortality associated with various chronic diseases. general practitioners (gps) play a key role in motivating a large proportion of the sedentary population to become physically active. very little is known about the exercise prescription practices of south african gps. this study aimed to determine the practices, attitudes toward and knowledge on exercise prescription among gps in sa and identify possible barriers why they do not prescribe exercise. methods: a self-administered, anonymous electronic questionnaire was circulated to a database of gps via email on three separate occasions, two weeks apart and was completed by a total of 349 gps. exercise prescription practices, attitudes towards exercise prescription and the importance thereof as preventative modality for chronic diseases were assessed. knowledge on benefits, risk factors, contraindications and compilations of exercise prescriptions were also assessed. results: substantially higher prescription rates were reported compared to international literature. a minority (18.0%) of the participants felt that exercise prescription will be too time consuming, while almost half (46.0%) of the non-prescribing doctors reported a lack of confidence in their knowledge to be able to prescribe exercise. approximately 98% of the gps believed that it should be part of their practice to prescribe exercise to their patients, despite the fact that their knowledge regarding recommendations for physical activity and the formulation of an exercise prescription was poor. conclusion: although gps reported a high prevalence of exercise prescription, insufficient knowledge about exercise prescription and appropriate lifestyle modifications were noticed. barriers to exercise prescription differ from international literature and should be investigated further. a lack in confidence and knowledge to enable safe and effective exercise prescription highlights a need to rethink the undergraduate medical curricula. takshita sookan affiliation: university of kwazulu natal additional authors: takshita sookan, andrew mckune, michael ormsbee, jose antonio, nombulelo magula, umesh lalloo, ayesha motala effect of a progressive resistance training program and whey protein intake on quality of life in human immunodeficiency virus infected individual receiving antiretroviral therapy. introduction: advances in hiv treatment in the last three decades has resulted in improved health, prolonged life and substantially reduced the risk of hiv transmission. [u1] this impact broadens to all facets of life, influencing quality of life (qol). progressive resistance training (prt) combined with effective supplementation can increase muscle mass and improve physical performance in persons with hiv infection and may enhance outcomes in these patients as well as improve qol. methods: forty hiv infected participants (40.8 ±7.7 yrs, 70.8 ±16 kgs, bmi 30.9 ±7.2 kg.m2) receiving art (≥18 months) were randomly assigned to either a whey protein/resistance training (rt) group (n=18), placebo/prt group (n=14) or control group (n=8). participants received either 20g whey or placebo (maltodextrin) pre and immediately post each rt workout. whole body rt was performed 2/week for 12 weeks. to assess qol the whoqol-hiv bref 31 was used which has six domains: physical, psychological, level of independence, social relationships, [u2] environment, and spiritual. the questionnaire was completed at baseline and then at 12 weeks. the mean score of questions within each domain was used to calculate the domain score. statistical analysis consisted of a two-way anova and sidak's multiple comparison post hoc testing. alpha was set at p ≤ 0.05. results: the physical domain showed a significant time effect (te) (p=0.02) with the placebo group increasing from baseline (17.69a.u.) to post (19.15a.u) (mean difference -1.5a.u., 95% ci -2.9 to -0.05a.u.). there were no significant changes in the supplement group. the social relationships domain exhibited a significant te (p=0.02) with the placebo group increasing significantly from 14.23a.u. to 16.54a.u post (mean difference -2.3a.u., 95% ci -3.9 to -0.7a.u.). environment domain showed a significant te (p=0.002) with both placebo (15.65a.u. to 16.46a.u.; mean difference -0.8a.u., 95% ci -1.5 to -0.09a.u.) and supplement groups (14.35a.u. to 15.03a.u.; mean difference -0.7a.u., 95% ci -1.3 to 0.04a.u.) demonstrating significant increases from baseline after 12 weeks of training. the spiritual domain indicated significant te (p=0.05) with the placebo group increasing from baseline (16.38a.u.) to post (17.92a.u) (mean difference -1.5a.u., 95% ci -2.8 to -0.3a.u.). there were no significant changes in the supplement group. there were no changes in the psychological or level of independence domains for the placebo and supplement groups. there were no significant changes in the control group for any of the six domains. conclusion: several components of qol improved in art treated hiv infected individuals that participated in the prt program. changes were predominately shown in the placebo group (domains 1, 4, 5, 6). this can be attributed to positive social and environmental effects of exercise programs. exercise training is an inexpensive and efficacious strategy for improving qol in this population with can impact other facets of their lives. jason tee affiliation: university of johannesburg additional authors: jason tee, jannie klingbiel, rob collins, mike lambert, yoga coopoo functional movement screen predicts severe contact and non-contact injuries in professional rugby union players introduction: rugby union is a collision sport with a relatively high risk of injury. the ability of the functional movement screentm (fms) to predict the occurrence of severe (≥28 days) contact and non-contact injuries in professional players was assessed. methods: 90 fms test observations were compared with severe injuries sustained during 6 subsequent months. a receiver operated characteristic (roc) curve determined the fms score that best predicted severe injury. 2 x 2 contingency tables were used to determine sensitivity, specificity and odds ratios of the prediction. results: mean fms scores were significantly lower in players who sustained severe injury (injured 13.1 ± 1.7 vs. non-injured 14.5 ± 1.4), and severe contact injuries (injured 13.1 ± 2.0 vs. non-injured 14.3 ± 1.5). a receiver-operated characteristic (roc) curve determined that odds of severe injury, contact injury and non-contact injury were 5.2 (95% ci = 2.0-13.9), 6.5 (95%ci = 1.8 to 23.0) and 4.3 (95%ci = 0.9 to 21.0) times greater respectively if fms score was below the relevant cut-off score. low active straight leg raise score (≤ 2) was also significantly associated with injury. players were divided into high-fms (≥14) and low-fms (≤ 13) groups to estimate the potential effect of low fms scores. survival analysis showed a greater fractional survival rate for high-fms group (≥14) versus a low-fms group (≤ 13) (81.4% 95%ci = 68.9 to 89.2% vs. 50.0% 95%ci = 31.3 to 68.7, p <0.05). the low-fms group spent mor e days injured (47 ± 47 vs. 25 ± 39 days) and took longer to recover (29 ± 38 vs. 10 ± 16 days) than the highfms group. conclusion: these findings indicate that fms score is a risk factor for severe contact and non-contact injury in professional rugby players. 34 jason tee affiliation: university of johannesburg additional authors: jason tee, yoga coopoo, mike lambert movement, impact and pacing characteristics of south african professional rugby union players introduction: global positioning system (gps) technology provides accurate, real-time movement pattern analysis. gps will improve understanding of the movement characteristics of players during professional rugby union matchplay. methods: 19 professional rugby players were tracked using gps during 24 matches during the 2013 rugby season. players were grouped as (1) backs or forwards and (2) tight forwards, loose forwards, scrumhalves, inside backs or outside backs. movements were categorized as walking (02m.s-1), jogging (2-4m.s-1), striding (4-6m.s-1) and sprinting (>6m.s-1). walking and jogging were classified as low intensity and striding and sprinting as high intensity movement zones. an inbuilt tri-axial accelerometer quantified impacts. pacing effects were determined by comparing 1st and 2nd half movement patterns and whole game players to substitutes. results: there was no difference between forwards and backs in relative distance covered or impact variables. backs reached higher maximum speeds than forwards (backs 8.8 ± 1.1 vs. forwards 7.6 ± 1.3 m.s-1, es = 1.0), and covered more distance than forwards in high intensity speed zones (forwards 10 ± 5 vs. backs 12 ± 4 m.min-1, es = 0.6). outside backs were the fastest positional group (9.4 ± 0.9 m.s-1, es = 0.4-2.2), while tight forwards covered the most distance in low intensity zones (57 ± 5m.min-1, es = 0.4–1.8) loose forwards and inside backs exhibited similar movement patterns. relative distance (m.min-1) increased in the second half for whole game players (7 &p lusmn; 9%). high-intensity running distance decreased in the second half for forwards (1st 10.0 ± 5.0 vs. 2nd 8.6 ± 3.8 m.min-1), but increased for backs (1st 10.6 ± 3.2 vs. 2nd 11.4 ± 2.5 m.min-1). substitutes demonstrated increased relative jogging (start 20 ± 5 vs. sub 24 ± 6 m.min-1) and striding (start 8 ± 2 vs. sub 11 ± 6 m.min-1) distance versus whole game players. conclusions: there are notable differences in the movement of professional rugby union players in different positions. fatigue results in reduced high-intensity running distance and this effect can be managed through the use of substitutes. hannah van buuren affiliation: isr, university of pretoria methods in monitoring a fast bowler in cricket introduction: fast bowlers cover 20-80% greater distance, exert 2-7 times greater high intensity (hi) distances, and have 35% less recovery time between hi efforts than other specialities in cricket. in addition, they are also required to undergo and absorb forces as high as 8xbw during each bowling delivery whilst laterally flexing, extending and rotating throughout their bowling action. it is no surprise that fast bowlers have been identified as the speciality highest at risk of injury in various countries. the aim of this data collection was to determine methods that can be used in practice by support staff to determine when the fast bowler may be at risk of injury and whether or not the fast bowler is bowling prepared prior to competition. methods: thirteen international fast bowlers were monitored for an entire cricket season by self-reporting their workloads using number of overs bowled, session types and time, as well as injury occurrence and time to play. results: the average number of balls bowled per week over the season was 120±39 balls with acute peaks reaching 258 balls in one week. conditioning on average for the bowling group was 169±14 minutes per week. trends from injuries sustained showed that muscle strain type injuries occurred over a short delay (1 week) between when the bowler experienced high workloads and breakdown where they could not play cricket due to injury. bone and tendon damage were seen over a long delay (36 week) between high workloads and breakdown. high workloads were experienced when the fast bowler spiked acutely to their chronic (rolling average of 3 weeks) workload. conclusion: this method of monitoring training loads will allow coaches and trainers to either lower or raise bowling and /or conditioning loads prior to competition or risk of injury, e.g. to ensure bowling loads have met the demands for the upcoming test match, or to ensure the fast bowler is fresh and at a reduced risk of injury. riaan van der merwe affiliation: morningside sports medicine centre additional authors: riaan van der merwe, natalie phillips isokinetics, posture and functional screening in professional cyclists-team mtn qhubeka introduction: an elite level cyclist rides between 25000 km and 35000 km per annum; compared to a recreational cyclist who only accumulates 7114 km. it is therefore surprising that so few studies exist to illustrate the findings of isokinetic, functional and postural testing modalities in elite cyclists. the purpose of this study is to present data collected in an elite group of cyclists. methods: twenty one professional road cyclists from the mtn qhubeka cycling team were screened prior to competing in the 2015 tour de france. the screening protocol included isokinetic testing, postural analysis, functional strength testing and flexibility of the lower body. isokinetic examination was performed using a system 3 biodex. peak torque to body weight ratios were evaluated at 60 degrees/s and 180 degrees/s for concentric knee extension/flexion and 60 degrees/s and 120 degrees/s concentric hip flexion/extension. postural analysis involved documenting asymmetry of bony landmarks to determine malalignment issues. functional evaluation included single leg squat and single leg jump squat tests. goniometry was used to evaluate hip internal, external rotation and passive hamstring flexibility. results: the cyclists' average age was 27.3 years with a mean body weight of 71.6kg. isokinetic testing revealed the hip extensors and knee flexors to be the stronger muscle groups. results indicated average peak tq/bw for knee flexors to be very strong (l = 3.08 nm/kg, r = 3.0 nm/kg) compared to general athletes' ratio of 1.85 nm/kg. however, of concern was the weakness in knee extensor strength average peak tq/bw ratio (l = 2.22 nm/kg, r = 2.27 nm/kg) compared to general athletes of 2.96 nm/kg. postural assessment indicated that only 2 cyclists had a neutral pelvic position and 3 cyclists' scapulae were level. during functional testing 4 % had good stability on l and r leg (ankle, knee and hip) during a single leg squat, 14 % had good stability on 1 leg only (left) with the 1 leg jump squat only 14 % presented good stability on both legs. flexibility tests illustrated that hip internal rotation (average: l = 35.57â�°, r = 35.05â�°) and hamstring flexibility (average: l = 87.76â�°, r = 88.95â�°) proved in line with norms, yet the average hip external rotation (l = 30.67â�°, r = 30.62â�°) was significantly reduced compared to the norm (45â�°). conclusion: these athletes could be at risk of injury considering the results. the performance of the team could be improved by enhancing knee extensor strength and addressing postural mechanics. cycling is a non-weight bearing sport thus the poor performances in functional testing. 35 babette van der zwaard affiliation: department of sport sciences, stellenbosch university additional authors: babette van der zwaard, kasper jansen, caroline finch, willem van mechelen, evert verhagen interventions preventing ankle sprains; predictors of compliance to neuromuscular training, bracing or combination therapy introduction: neuromuscular training, wearing a brace or a combination of both are the most occurring interventions for preventing reoccurring ankle sprains in sports. the effectiveness depends on compliance to the intervention. the aim of this study was to describe the associations between participants' person-related potential predictor variables and cumulative compliance with interventions for preventing ankle sprains: neuromuscular training, wearing an ankle brace, and a combined training and bracing. design: secondary analysis of compliance data from a randomized controlled trial (rct) comparing measures preventing ankle ligament injuries. methods: ordinal regression with a backward selection method was used to obtain a descriptive statistical model linking participants' person-related potential predictor variables with the monthly cumulative compliance measurements for three interventions preventing ankle ligament injuries. results: having had multiple previous ankle injury versus a single ankle injury was significantly associated with a higher compliance with all of the preventive measures (or 1.72; 95% ci 1.09–2.70). overall compliance with bracing and the combined intervention was significantly lower than the compliance with nm training. per group analysis found that participating in a high-risk sport, like soccer, basketball, and volleyball, was significantly associated with a higher compliance with bracing (or 3.39 95% ci 1.49-7.44), or a combined bracing and nm training (or 2.49 95% ci 1.27-4.92). in contrast, participating in a high-risk sport was significantly associated with a lower per group compliance with nm training (or 0.43 95% ci 0.190.96). conclusions: when choosing an appropriate intervention to prevent reoccurring ankle sprains practitioners should take into account the nature of the sport a patient practices. furthermore, it is advisable to pay extra attention to patients who are returning to sports after their first ankle sprain to stimulate compliance to the chosen intervention. arnold vlok affiliation: department exercise and sports sciences additional authors: arnold vlok, louis holtzhausen, marlene schoeman rehabilitation and return to play after anterior cruciate ligament reconstruction: a systematic review and development of a conceptual rehabilitation framework introduction and aim:there is a high risk for subsequent injury after anterior cruciate ligament reconstruction (aclr) when post-operative rehabilitation is not managed according to physiological principles. the primary aims of this study was 1) to conduct a systematic literature review on the influence of the physiological healing process of the graft on the physical rehabilitation process leading up to return to sport (rts) following aclr, and 2) to develop a conceptual framework for rehabilitation and rts (ethics clearance: ecufs 15/2013). methodology: a systematic review was conducted according to the prisma guidelines. randomised controlled trials (rcts), prospective cohort (pc), cross sectional (cs) studies and descriptive epidemiological studies from 1985 to 2013 were reviewed. electronic databases which were searched included medline, academic search complete, pubmed and sportdiscus. twenty eight articles were selected for data extraction, which were categorised in three main categories, namely graft healing (5 articles), rehabilitation protocols (15 articles) and return to sport criteria (8 articles). results: there is a dearth of literature aligning the physiological healing process after aclr and the physical rehabilitation thereof. major differences occur in methodology and in rehabilitation protocols in the literature. physiological healing of the autograft and quadriceps recruitment deficits take up to 2 years for full restoration. rehabilitation interventions after aclr include strength, neuromuscular and functional training according to the physiological responses of the acl graft and neuromuscular adaptation. current trends in rehabilitation planning and intended outcomes follow these principles. weakness or asymmetry of the injured versus uninjured side often persists after rts. conclusion: a 0-3 months/3-6 months/6-12months/rts conceptual framework for rehabilitation of aclr was developed from the literature, considering the interdependence of the healing process of the acl graft and neuromuscular, strength and functional training. aclr patients need to be managed within a time based as well as individualized criterion based rehabilitation progression model. estelle watson affiliation: centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand additional authors: estelle watson, lisa mickelsfield, are our pregnant mom's exercising for two? physical activity profiles of black south african pregnant women background: excessive gestational weight gain (gwg) has been shown to be an predictor of adverse maternal outcomes, such as gestational diabetes mellitus, preeclampsia and caesarean delivery. it is however, one of the most important modifiable risk factors for pregnancy complications. unsurprisingly, engaging in physical activity during pregnancy has been shown to reduce excessive gwg, and therefore may provide a protective health effect. in south africa, women from low socio-economic urban areas are particularly susceptible to issues of obesity and inactivity. therefore, understanding the activity and health profiles of this vulnerable population is a crucial step to improving the health of our women and future generations. methodology: pregnant women (14-18 weeks gestation) attending the developmental pathways of health research unit at chris hani baragwaneth hospital in soweto were invited to participate in the study. demographic information was gathered through questionnaire, and anthropometric measurements were taken by trained research assistants. physical activity was measured using a hip-worn accelerometer (actigraph gxt3) for 7 days. results: one hundred and ten women participated in the study (n=110; age: 30±6yrs). on average, women weighed 69.8(±13.8kg), and had a body mass index of 27.1(±4.9) at 14-18 weeks. gestational weight gain over the course of pregnancy was 8.4(±4.7kg). objective measured showed that sixty six women (60%) were sufficiently active, meeting the 150 minutes of mvpa per week, however, women spent on average 7.3(±2.8hrs/day) in sedentary pursuits. discussion: many black south african pregnant women are not sufficiently active, and spend the majority of their day in sedentary activities. in addition, this research suggests that many women falling pregnant are already overweight, and therefore early lifestyle interventions may be critical in preventing disease in this population. the health risks of overweight and a sedentary lifestyle may extend to birth outcomes for the baby and postpartum outcomes for the mother. therefore, public health interventions to improve activity levels, in this unique period in a women's life, is warranted. 36 ming hao zheng affiliation: winthrop professor and director of research at the translational orthopedic research centre, sir charles gardner hospital, perth and the associate dean (international) of the faculty of medicine, dentistry and health sciences at the university of western australiaadditional authors: additional authors: allan wang, ming hao zheng evidence of long term durability on autologous tenocyte injection (ati) for treatment of chronic lateral epicondylitis purpose: chronic lateral epicondylitis is associated with degenerative tendon changes, extracellular matrix breakdown and tendon cell loss. to continue our previous 12 month pilot study on ati for severe tendinopathy associated with chronic lateral epicondylitis (wang et al ajsm 2013), herein we provide long-term follow up (36 months) data on ati efficacy. methods and materials: patients with severe refractory lateral epicondylitis underwent clinical evaluation and mri prior to intervention. a patellar tendon needle biopsy was performed and tendon cells expanded by in vitro culture in a gmp-certified tga-licensed facility. as single injection of autologous tenocytes into the common extensor tendon origin tendinopathy under ultrasound guidance was performed. patients underwent serial clinical evaluations (vas pain, quickdash, grip strength and mri) for up to 5 years post-injection. repeat mri scanning was performed at 1 year and at least 3 years post-injection. results: twenty patients (11m:9f; mean age 49.4 years) were included in the study, with three patients withdrawing consent prior to ati. mean symptoms duration pre-recruitment was 31 months. mean follow-up time was 4.5 years. no biopsy complications or any adverse events, infection or excessive fibroblastic reactions at the injection site were observed. one patient elected for surgery three months post-ati after re-injury, and one died of natural causes during follow-up. in the remaining 15 patients, mean pain scores improved from 5.7 to 1.2 at final follow-up (p<0.001). mean quickdash score and grip strength scores also significantly improved over follow-up (84% and 207% increase, respectively; p<0.001). mri scoring of tendinopathy grade at the common extensor origin improved significantly at 12 months (p=<0.001), and was maintained to final follow-up. conclusion: ati significantly improved clinical function and mri tendinopathy scores at 3-year follow up in patients with chronic lateral epicondylitis having previously undergone unsuccessful conservative treatment. this study advocates the long term durability of ati in treating tendinopathy. ming hao zheng affiliation: affiliation winthrop professor and director of research at the translational orthopedic research centre, sir charles gardner hospital, perth and the associate dean (international) of the faculty of medicine, dentistry and health sciences at the university of western australia additional authors: greg janes, ming hao zheng autologous tenocyte injection (ati) for gluteal tendinopathy: a pilot study introduction: gluteal tendinopathy is a common cause of lateral hip pain. no treatments have effectively improved the poor health outcomes and disability of the condition. autologous tenocyte injection (ati) is a novel cell therapy that has shown promise in other tendinopathic conditions. therefore, this prospective pilot study investigated the effect of ati in 12 patients with clinical and radiological evidence of gluteal tendinopathy. method: a patellar tendon needle biopsy was performed under local anaesthetic and tendon cells were expanded by in vitro culture in a gmpcertified, tga-licensed facility. autologous tenocytes were injected into the gluteal tendinopathy under ultrasound guidance on a single occasion. all patients were functionally assessed preoperatively and at 3, 6, 12 and 24 months postoperatively with the oxford hip score (ohs), the merle d'aubigne postel score (mdp), the 36-item short-form health survey (sf36) and the visual analogue pain scale (vas). a patient satisfaction survey was also given 12 months postoperatively. magnetic resonance imaging (mri) scans were performed preoperatively and 6 months postoperatively for structural assessment of the gluteus medius tendon. results: twelve patients, all female, with a mean age of 53 (range 40-65) years and average duration of symptoms of 33 months (range 6-144) were included in the study all patients had clinical symptoms and signs of gluteal tendinopathy, with diagnosis confirmed by mri all patients. no patella biopsy site complications or treatment site infections were noted. significant (p<0.05) functional improvement to 24 months postoperative was observed across all mean score outcomes: vas (pre 7.25, post 2.73), ohs (pre 24.00, post 39.45), mdp (pre 11.67, post 16.55) and sf-36 pcs (pre 28.08, post 41.59). one patient did not respond and elected surgery. patient satisfaction survey results demonstrated that 64% of patients were 'satisfied' or 'highly satisfied' with their ati outcome. follow-up mri scans did not demonstrate notable changes in the radiological appearance of th e tendinopathic tissue in most cases. discussion: ati by single injection significantly improved clinical outcome in this pilot study of gluteal tendinopathy at 24 months follow-up. however, the safety and efficacy of ati requires substantiation given the small pilot sample size. we believe this study has shown encouraging early outcomes that warrant larger randomised controlled study of ati for gluteal tendinopathy. 37 marelise badenhorst affiliation: division of exercise science and sports medicine, department of human biology, faculty of health sciences, uct additional authors: marelise badenhorst prof willem van mechelen, prof mike lambert, prof evert verhagen, wayne viljoen, clint readhead, gail baerecke, chris burger, petro jackson, james brown a comparison of rugby-related catastrophic spinal cord injury rates by province in south african rugby introduction: the catastrophic injury rates in south african rugby have previously been reported at an “acceptable” level of risk (0.1–2.0 cases per 100 000 players). to further reduce this risk, the south african rugby union (saru) requires that all coaches and referees undergo biennial training as a core component of saru's dedicated rugby safety programme, boksmart. there are approximately 300 000 players from 14 different rugby regions (< rugby regions ('provinces”) in south-africa. understanding the difference in catastrophic injury risk between the provinces is important for a nationwide intervention such as boksmart. thus, the aim of this study was to compare the catastrophic injury rate between the 14 south african rugby provinces between 2008 and 2014. methods: acute spinal cord injuries (asci) with permanent outcomes (neurological deficit, quadriplegia or fatal) were obtained from boksmart/chris burger petro jackson players' fund (cbpjpf). the player numbers in each province were obtained from saru's 2013 census report. annual average incidence rates between 2008 and 2014 were calculated for each province and compared statistically using a poisson regression with a 95% level of confidence (p<0.05). results: the overall incidence rate for permanent outcome asci was 2.33 (95%ci: 0.34 to 4.32) per 100 000 players. david bentel affiliation: centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand additional authors: david bentel, khavish harry, marc booysen the anthropometric and physical performance characteristics of second division male footballers from gauteng background: there is a paucity of research concerning the anthropometric and physical performance characteristics of male footballers from south africa according to player position. aim: the aim was to describe the anthropometric and physical performance characteristics of male footballers playing in the second division (gauteng stream) according to player position. methods: one hundred and twenty four male footballers (age: 22.1 ±2.72 years) (strikers = 30; midfielders = 40; defenders = 39; goalkeepers = 15) from five football teams performed the following anthropometric and physical performance measurements: body mass, stature, upper body power (overhead medicine ball throw), lower body power (countermovement jump), agility (illinois test with ball), speed (10 and 30m sprints) and intermittent running endurance (yo-yo level 1). results: goalkeepers were heavier than strikers and midfielders (p = 0.002) and strikers were shorter in stature than goalkeepers and defenders (p = 0.003). goalkeepers and defenders had greater upper body power than forwards and midfielders (p = 0.0002), however goalkeepers ran less distance in the yo-yo ir1 than midfielders and strikers (p = 0.001). no positional differences were observed for countermovement jump height, agility and sprints (10m and 30m) (p values = 0.14; 0.06; 0.24; 0.18, respectively). conclusion: the results suggest that there is little heterogeneity regarding the physical performance characteristics of male second division footballers (gauteng) in the outfield position. it is recommended that individualising physical conditioning based on the positional demands may need to be addressed in this league. keywords: soccer, football, anthropometric, counter movement jump, yo-yo, sprints gerrit jan breukelman affiliation: university of zululand variable isotonic resistance training in lower limb strength and flexibility of recreational cyclists and runners we determined the effects of an 8-week, home-based jump stretch flexband® (jsfb) exercise programme on the strength and flexibility of a group of recreational runners and cyclists, with a control group of runners and cyclists who did not alter their daily training regimes. the use of the jsfb significantly increased the dominant and non-dominant hip flexor flexibility of the experimental group (p = 0.0002 and 0.0004, respectively). significant benefits were also found in hamstring flexibility (p = 0.041), evidence indicating a steady increase within the experimental group. there was also a significant, but inconclusive, increase in the control group's quadricep flexibility in both dominant and non-dominant legs (p = 0.025 and 0.046). there was no significant difference in strength gains, as the experimental group's peak torque–best repetition for extension of the dominant leg was p = 0.37 and the non-dominant leg was p = 0.19, respectively. thus, using the jsfb appears likely to lead to improved flexibility of an athlete's lower limb muscles, which is an important finding due to the significantly less amount of research that has been done on the large muscle groups compared to the smaller muscle groups. abstracts: e-posters 38 erna bruwer affiliation: phasrec (nwu, potchefstroom campus) additional authors: erna bruwer, magdeleen gous, barbara van dyk do shoulder stability exercises create similar increases in the acromiohumeral distance of cricket players as the scapular assisted test? introduction: prolonged participation in overhead sports creates shoulder muscle imbalances that eventually alter the efficacy of the shoulder stabilizer muscles and heighten injury risk such as subacromial impingement syndrome. the aim of this study was to determine if a six week shoulder stability exercise intervention performed during the competitive season results in similar increases in the acromiohumeral distance (ahd) of cricket players as with the application of the scapular assisted test (sat). method: players (n=47) from the north-west university cricket squad voluntarily participated in this shoulder injury prevention project. baseline testing included ahd measurements performed by a radiographer at different humeral abduction angles (0°, 30° and 60°) with and without the application of the sat. players were then randomly assigned to an intervention and control group. the control group continued with their normal inseason programme. the intervention group additionally performed shoulder stability exercises twice a week for six weeks under supervision of a biokineticist. results: the sat application had a significantly greater effect at 60° of humeral abduction on the dominant shoulder (p=0.013) compared to the nondominant shoulder. also, the dominant shoulder indicated significantly less narrowing of the ahd between 0° and 60° (p≤0.001), as well as 30° and 60° (p≤0.001) ranges when the sat was applied. the players in the intervention group indicated similar widening of the ahd at 0° and 30° humeral abduction angels as the ahd measures with the sat application. the exercise intervention on average significantly widened the ahd of both the dominant (p=0.019) and non-dominant shoulders (p=0.035) at 0° abduction. conclusion: shoulder stability exercises performed additional to normal training regimes during the competitive season result in similar widening in the ahd of cricket players at 0° and 30° of humeral abduction than when the sat is applied. these exercise modalities could therefore be incorporated in the training regimes of overhead athletes to manage shoulder dyskinesis. keywords: shoulder dyskynesis and overhead athletes, acromiohumeral distance, shoulder dyskinesis rehabilitation tanya camacho affiliation: university of pretoria the correlation between chest circumference and spirometry measurements over a 19-week intense training programme introduction: spirometry testing as a screening tool for pulmonary disease is expensive and often inaccessible. this study aimed to determine whether chest circumference measurements could be used as an inexpensive pre-screening tool for pulmonary disease irrespective of changes in fitness. methods: a quantitative, prospective correlational research design assessing chest circumference measurements, spirometry and maximal oxygen uptake (vo2 max) of male and female south african recruits (n=235) undergoing 19 weeks of basic military training (bmt) was used. subjects were tested in weeks 1, 12 and 19 of bmt. overall, 26 subjects matched the inclusion criteria and completed all measures in all three testing sessions. parametric descriptive and inferential statistics were used. results: data analysis showed weak correlations (r<0.4) between chest circumference and spirometry. significantly positive strong correlations between forced vital capacity (fvc) and vo2 max in weeks 1, 12 and 19 (r=0.682, p<0.01; r=0.616, p<0.01 and r=0.697; p<0.01, respectively) and between forced expiratory volume in 1 second (fev1) and vo2 max in weeks 1 and 19 of bmt (r=0.628; p<0.01 and r=0.658; p<0.01, respectively) were observed. additionally, a significantly positive moderate correlation between fev1 and vo2 max in week 12 of bmt (r=0.554; p<0.01) was noted. conclusions: this study demonstrates that chest circumference measurements appear not to be a reliable substitute for spirometry screening in a young healthy active population. future research using a larger sample is recommended. keywords: pulmonary disease; chest circumference measurements; spirometry; forced vital capacity; forced expiratory volume in one second; basic military training james clark affiliation: department physiology, university of pretoria additional authors: james clark, maegan anne von finckenstein, mareli joubert, danielle lincoln a retrospective study of injuries in rowing during a single season introduction: sport injury profiling from epidemiological data provides important information for preventive and management strategies by scientific and medical support teams. competitive rowing demands consistent, long-term intensive training, and physical injury represents both a risk of and a threat to optimal preparation. the aim of this study was to retrospectively document injuries sustained by competitive rowers in south africa over one full season in an effort to obtain a baseline injury profile of the sport. methods: at a season-ending national regatta, one hundred and fifty-seven (157) rowers (88 men, 69 women) aged (mean ± sd) 21.2 ± 2.1 years, with 5.0 ± 3.5 years rowing experience, representing nine university rowing clubs from across south africa volunteered as participants. a three-part questionnaire containing closed-ended questions on personal data, rowing training and injury information pertaining to that season was completed. participant competitive level ranged from university club representatives to international medal winners. results: eighty (80) rowers (50.9% of respondents) admitted sustaining at least one injury requiring one or more missed training sessions, with 103 separate injuries reported. lower back (23.3%), knee (13.6%) and shoulder (10.7%) were the most commonly injured regions within a variety of involved sites. the vast majority (68.9%) of injuries were sustained during training as opposed to competition, and more often during rowing (42.7%) than other training modalities. approximately 30% of cases represented a recurrence of a prior injury. muscle strain (48.5%) was the most reported type of injury. an injury typically resulted in 7.0 (range: 0.5-180.0) days of missed training. while national representative rowers made up less than one fifth of participants they reported over one third of the injuries documented. conclusions: a high percentage of rowing injuries in south africa involve the lower back, congruent with international data. furthermore, overuse injury owing to training load is implicated most often in the aetiology based on the reported nature and modality of injury and the higher injury incidence amongst rowers at higher competitive levels. this data has important practical utility in strategies aimed at managing athlete health and optimizing preparation time in the scientific support program to the national rowing squad. 39 demitri constantinou affiliation: university of the witwatersrand additional authors: demitri constantinou, abdul hameed ismail, yoga coopoo prevalence of overweight in grade-one learners and parent perceptions of childhood nutrition / physical activity the problem of childhood obesity in south africa has reached epidemic proportions. it is estimated that one in five south african children are either overweight or obese; with twenty percent of children under the age of six being overweight. this is mainly due to a poor diet and a lack of exercise. the aim of this study is to determine the overweight / obesity prevalence amongst grade-one learners at selected schools in the west rand, mogale city. the weight and height of each subject was to be physically measured by the researcher and compared to norms for that age category. this study further aims to determine their parents knowledge / perceptions regarding childhood nutrition and physical activity. to this end a questionnaire was constructed so that parental knowledge / beliefs could be assessed. this study has found both overweight and underweight within the same population. the results indicate overweight / obesity in seventeen subjects (3.7%). eleven girls (4.8%) and six boys (3%) were overweight representing a boy to girl ratio of 1: 1.8 among the overweight group. among the overweight subjects, girls represented 65% while boys represented 35%. this study has also found underweight / stunting of growth among the eight and nine year old subjects as their weight for height fell below the 25th percentile. further classification of the study sample according to school-fee structure revealed that all subjects with overweight / obesity were found within low-fee schools, representing 4%. one boy and one girl each were found with obesity among the overweight group having a body mass index (bmi) of 23.8 and 24.8 respectively. therefore obesity was found in 12% among the overweight group and within lowfee structure schools. shereen currie affiliation: university of zululand comparison of lifestyle habits, sleep and activity patterns between normal, overweight and obese individuals using the bodymedia®fitarmband. the aim of this study was to compare the lifestyle habits, quality of life, sleep and activity patterns between normal, overweight and obese individuals using the bodymedia®fitarmband. thirty (30) participants volunteered to participate in this study, and were divided into three groups. the first group consisted of normal weight (n = 8) participants (bmi 18.5 – 24.9 kg/m2); the second group (n = 7) consisted of overweight participants (bmi 25.0 – 29.9 kg/m2) and the third group (n = 15) consisted of obese participants (bmi ≥30.0 kg/m2). participants had to wear the armband for 7 consecutive days and fill out the following 4 questionnaires: 1) who quality of life questionnaire; 2) health at work survey; 3) international physical activity questionnaire; 4) food frequency table. furthermore, participants had to log their daily food consumption in a food log book. after the 7 days the data collected was analyzed using an anova and descriptive methods. results showed significant differences in calorie expenditure (p=0.033), activity patterns (p=0.017), amount of steps walked per day (p=0.018) and the amount of hours slept per night (p=0.45) between the three groups. the overweight group had higher energy expenditure, activity patterns, and the number of steps per day. the normal group recorded the most hours of sleep, with obese group sleeping the least amount of hours. in conclusion, overweight and obese individuals sleep fewer hours than normal weight individuals. whether the lack of sleep in these groups caused weight gain or was the result of being obese or overweight could not be determined. the overweight group was more active and had higher energy expenditure than the obese group as hypothesized, but these values were also higher than the normal group. this could have been caused by only considering bmi for classification, leaving out lean muscle mass as a contributing factor to increased weight. key words: lifestyle habits, sleeping patterns, physical activity patterns, bodymedia®fit armband. muhammad dawood affiliation: university of pretoria additional authors: muhammad dawood, agatha johanna van rooijen, piet j becker, anna maria marais the interand intra-rater reliability of a technique for assessing the length of the latissimus dorsi muscle background: evidence-based practice requires the use of objective, valid and reliable tests for measuring the length of a muscle. no evidence of reliability for any technique testing the length of latissimus dorsi (ld) was found. purpose: to assess the inter-rater and intra-rater reliability of a technique adapted by comerford and mottram (2012) for assessing the length of ld. methods: fifty-six students from the university of pretoria's physiotherapy department were the participants in this study. four physiotherapists with varying numbers of years of clinical experience independently performed the test for assessing the length of ld. the test was performed twice by each physiotherapist on every participant and two measurement sessions took place. a pilot study wascarried out to test and time the procedure. the intra-class correlation coefficient(icc) as determined in a mixed-effects gls regression analysis was used to assess the inter and intra rater reliability of the ld length test. a 0.05 level of significance was employed. major results: a sample of 56 participants provided an intraclass correlation coefficient (icc) that varied between 0.55 and 0.76 and this is regarded as moderate to poor reliability.. the icc between the experienced raters was found to be 0.48, with a novice rater having an icc of 0.48 as well. the icc between all the raters was 0.33. conclusion: the poor reliability of the technique testing the length of ld was identified and addressed in order for adequate usage thereof, in research and in practice. recommendations were made. key words: latissimus dorsi, muscle length test, dysfunction; reliability; glenohumeral joint 40 donna donlon affiliation: sports medicine university of pretoria additional authors: donna donlon, helen bayne, rina grant hip and groin pain in sub elite south african footballers introduction: groin injuries are common in football players, attributed largely to the nature of the sport involving rapid accelerations, decelerations, abrupt directional changes and kicking. it has been suggested that up to a third of players will sustain a groin injury in their careers and this may mean months off from the field, and predispose them to further injuries. previous groin injuries are a well-identified risk factor for sustaining future groin injuries, suggesting that players are inadequately rehabilitated or that the original predisposing risk factors have not been addressed. objectives: the study aims to describe the prevalence, nature and treatment patterns of groin injuries in sub-elite players, and to investigate differences in hip strength and range of motion between players with and without a history of groin injury. method: thirty sub-elite male players were interviewed and then assessed using the copenhagen hip and groin outcome score (hagos) questionnaire, isokinetic hip flexion/extension strength, adductor squeeze test and range of motion. results: seventeen players (57%) reported a previous groin injury, of whom five (29%) stated that they had not soughttreatment from a medical professional. of the players who consulted a sports physician (6%) or physiotherapist (65%), the diagnoses included adductor strain (35%), inguinal rupture (18%), iliopsoas muscle injury (12%), hip joint pathology (6%) and chronic groin pain (6%). the average time before full return to play was 25 days. previously injured players had a significantly lower hagos score (83.4 ± 15.9) than the non-injured players (92.0 ± 5.2). no significant differences in hip flexion/extension isokinetic strength, hip range of motion and adductor strength were identified between the two groups. conclusion: the prevalence of groin injuries in this population is very high and requires lengthy rehabilitation time. only two-thirds of players consulted a medical practitioner with their injuries, increasing the likelihood that rehabilitation was inadequate. improved player and coach education regarding injury management may be required for better rehabilitation, in order to reduce subsequent injuries. adiele dube affiliation: sports scientist blood pressure among zimbabwean urban primary school children aged 5 to 11 years. background: following few publications available with data on blood pressure profiles of zimbabwean population, especially children and adolescents, few data exist on urban and rural school going children. the aims of this study were to examine the incidence of hypertension (ht) among zimbabwean urban chzimbabwean urban children residing in kwekwe; and to determine the relationship between body mass index (bmi) and blood pressure (bp) among them. the study involved 480 primary school children (230 boys and 250 girls) aged 5–11 years. methodology: stature and body weight were measured using standard procedures. bmi for gender and age defined overweight. bp was monitored for thrice consecutively using validated electronic devices (omron 7051t). ht was determined as the average of three separate bp readings where the systolic or diastolic blood pressure was ≥ 95th percentile for age and sex. results: the incidence of overweight among the girls (3.6%) was higher compared with the boys (2.7%). both systolic and diastolic pressures (sbp and dbp) increase with age in both sexes. potential development of hypertension among the children is noticeable at early childhood development (ecd) level for both boys and girls; 1.8% and 1.5% respectively and ranged from 0.8% to 1.8% for boys and 2.0% to 5.3% for girls. the overall incidence of hypertension was 1.5% and 2.6% in boys and girls, respectively. the highest noticeable value for boys was at ecd and decreased with increase in grade level. the incidence of hypertension (sbp > 95th percentile) was 0.4% and 0.2% in boys and girls, respectively. for the girls there was a progressive increase in the tendency towards development of hypertension from ecd to 6th grade except a small d ecrease in 3rd and 4th grade levels. girls in the 6th grade level showed the highest value of incidence of hypertension (5.3%). the blood pressures (sbp and dbp) significantly correlated with age, stature, body mass and bmi (p<0.05). conclusion: the findings demonstrate that elevated blood pressure is prevalent among urban zimbabwean children and that there is need for routine measurement of bp to children residing in this region as part of physical examination for physical activity in schools. the use of bmi cutoffs tailored to metabolic risks may be vital for assessment of overweight. bp increased with age in both sexes, and this significantly correlated with age, stature, body weight and bmi. overweight, body mass index, blood pressure, mining industry, urban children, zimbabwe sean finaughty affiliation: university of pretoria additional authors: sean finaughty, hannah van buuren, jamie schultz changes in hydration status, cognition and movement time in male cricket players during three consecutive days of match play introduction: changes in hydration have been shown to negatively affect performance. in cricket, there are increasingly more matches with greater intensities placing greater demands on players. this along with increased exposure to higher temperatures and humidity, increasing time spent in the field wearing protective equipment and clothing which are not effective for sweat evaporation may lead players to extreme thermal stress. this study examined changes in hydration status, cognition and reaction to an audio and visual stimulus, during the fielding innings' of three day cricket in male cricket players. methods: twenty-two male academy cricket players (age 19±1years, body mass 80.5±8.2kg) participated in the study. hydration status measures included body mass (bm), a subjective thirst rating (tr) and urine osmolality (uosm). cognition (letter digit substitution test ldst) and audio and visual reaction timing test were also examined. daily measurements were recorded on arrival prior to breakfast (baseline) and at the start and end of each fielding innings (preand post-innings). results: statistical differences observed between daily baseline measures were inconsistent for both baseline and preand post-innings measurements across the three days. mean decrements in bm without correction for fluid and food intake ranged from 1.8 to 3.7%,while values with correction for fluid and food intake produced significant netinnings decreases in bm of 0.360.78% (p<0.05). increased tr and decreased uosm trends associated with decrease in bm were observed but no statistical significance was found. ldst and audio-visual reaction timing indicated no significant or consistent changes across the five innings' studied. conclusion: the potential for dehydration (>2% decrease in body mass, uosm>900mosm/l and high tr) during the fielding innings is a reasonable, viable concern for cricketers. however, in this study, fluid and food consumption practices were sufficient to limit any potentially deleterious effects of dehydration on cognition and reaction timing. 41 chrisna francisco affiliation: university of the free state additional authors: chrisna francisco, frederik coetzee mental toughness of rugby players during periodization phases information on the contribution of psychological skills and mental toughness on performance is still limited within the sporting context, even though it has been proven that these factors influence sporting achievement. similarly, no agreement on how to develop and improve mental toughness during training programs has been achieved. the aim of this study was to explore the differences in mental toughness of rugby players during periodization phases, as well as the differences in mental toughness between rugby 'forwards' and 'backs'. data from rugby players, who participate in the sport on a university and regional level, was obtained by means of the psychological performance inventory; that the inventory was completed by all players during the preparatory, competition, and transition periodization phases. differences in mental toughness were analysed using a repeated measures mixed linear model with periodization phase, team and group (forwards versus backs) as fixed effects, and fitting an unstructured covariance matrix to the repeated measures of mental toughness. from this model, mean values for each group and phase, as well as differences between mean values between periodization phases together with associated p-values and 95% confidence intervals were calculated. the results indicated that there are significant differences amongst rugby players' attitude control (p=0.00), namely significantly higher values during competition phase than during the preparation phase. when the components of mental toughness were compared for the competition phase and the transition phase, significant differences were found for overall mental toughness (p=0.01), motivation (p=0.04), and attitude control (p=0.05), with the latter phase scoring lower than the competition phase. no significant differences were found between the mental toughness components of the preparation phase compared to the transition phase. the mental toughness of forwards and backs was not significantly different, although there was a tendency for backs to have higher mean values for all of the mental toughness components. this study was designed to explore mental toughness of rugby players during periodization phases, and could be the foundation for future studies to further investigate which mental toughness components seems to be dominant during specific periodization phases – and which components still have room for improvement in order to facilitate the development of training guidelines that enhances athletes' performances and help them to achieve their goals. keywords: mental toughness, rugby, periodization phases. 42 chrisna janse van rensburg affiliation: university of the free state additional authors: riaan schoeman, frederik coetzee positional tackle and collision rates in super rugby the aim of this study was to evaluate differences between playing positions with respect to tackle and collision rates in a rugby game, and to determine the collision rates of individual playing positions in professional rugby union. data from 30 matches (both teams involved) during the 2013 super rugby season were captured and supplied by the cheetahs super rugby franchise using the verusco trymaker pro. the results show that there were significant differences between positional groups regarding the tackle rates; however the front row players and the second row players did not differ significantly (positions 1, 2, or 3 vs positions 4,or 5; p = 0.0715 to p = 0.6324). within a positional group, the difference between the inside centre and the other inside backs was significant (9 vs 12; p = 0.0029, 10 vs 12; p = 0.0045 and 12 vs 13; p = 0.0100). furthermore, there were no significant differences between second row players and the eigthman (4 vs 8; p = 0.4183 and 5 vs 8; p = 0.6863) although significant differences were found between second row players and the rest of the loose forwards (6 and 7). a significant difference (p <0.05) exists between all forwards and backs when collision rates are compared. in summary, this study revealed significant inter-positional differences in tackling and collision rates within the same positional group. keywords: rugby, tackle, collisions, playing positions, rucking. chrisna janse van rensburg affiliation: university of the free state additional authors: riaan schoeman, frederik coetzee kicking statistics that discriminate between winning and losing teams in the 2013 super rugby season kicking is one of the fundamental movements associated with rugby union and the successful completion of this task may lead to team success. furthermore, kicks are an aspect of the game which has seen noticeable changes. the current trend in video analysis is the development of performance profiles to describe individual or team patterns created from a combination of key performance indicators. however, despite the range of detailed analyses there is no obvious structure or progressive evolution to the development of analysis methods and there are still large gaps in the literature, especially in the area of rugby. previous research indicated that losing teams were more likely to try to control the ball through accurate passing, where winning teams had a more kick-related game plan. in this study, a total of 900 professional rugby players that participated in 30 games played during the 2013 super rugby competition were observed. two games from each of the participating franchises were used. the aim of the study was to discriminate between the kicking statistics of winning and losing teams in the 2013 super rugby season. previous research found that kicking the ball away and making more tackles than the opposition were the two most influential factors in determining winning from losing. results from the present study suggest that winning teams tend to kick the ball more (average of 25.77 kicks per game) than losing teams (20.23). losing teams gain a mean total of 660.0 m per game in comparison to winning teams, 901.4 m per game. thus the study showed that winning teams kick more, with greater distance. winning teams also have greater kick frequency when attacking minutes of play are considered. more research is required to account for weather, importance of the game and match venues. good playing conditions were associated with large increases in tries and points scored, and with large decreases in kicks in play and participation time per player. keywords: kicking, performance indicators, metres gained. chrisna janse van rensburg affiliation: university of the free state additional authors: riaan schoeman, frederik coetzee passing statistics that discriminate between winning and losing teams in the 2013 super rugby season. passing is a common performance indicator in rugby since this action is performed by all players. evaluating the indicators such as number of kicks, rucks, mauls, passes, and tries can provide valuable insight into team performance and may be used to predict the future performance of rugby union teams. increases in passes, tackles, rucks, tries, and ball-in-play time were associated with the advent of professionalism therefore, this study evaluated the number of passes during the 2013 super rugby season and to determine if the number of passes discriminated between winning and losing teams. data was gathered from 30 games during the 2013 super rugby season using the verusco trymaker pro. data collected were statistically analysed to show the number of kicks made during a season of super rugby. the results of this study suggest that losing teams tend to pass the ball more (157.41) than winning teams (127.02). in agreement with these results, winning teams have higher counts of kicks. the study shows a significant difference between winning teams and losing teams regarding total passes, bad passes, and good passes (p = <0.05). it can be concluded that factors such as the individual playing position, skill level of players, weather and game plan can determine the outcome of passing as a variable. different teams use a variety of game plans and can influence the number of passes or kicks per match, and so also the outcome of the game. keywords: passes, performance indicators, good passes, bad passes barry gerber affiliation: north-west university the status of fundamental movement skills of 3-year boys and girls the period 3 to 5 years is a crucial time in the motor development of a child during which maturation constantly occurs. contradictory results are found in literature regarding the current status of fundamental movement skills of 3 year old children and possible gender differences in this time period. the aim of this study was to determine the status of the fundamental movement skills and possible gender differences of 3 year old children by using the kinderkinetics preschool assessment (pienaar et al., 2013). a cross-sectional research design was conducted on 51 children (19 girls, 32 boys) with a chronological age of 3.0-3.11 years from 3 selected nurseries in the potchefstroom and jankempdorp areas. for descriptive purposes the data was analyzed by means, standard deviations, minimum and maximum values. an independent t-test (possible gender differences) and effect size were used for statistical(p≤0.05) and practical (d≥0.8) significance. statistical significance were found where girls outperformed boys in hopping on one leg (right) and identifying body parts and boys outperformed girls in standing on one leg (left), kicking a moving ball and copying hand signals. improvements were found in some skills while other skills correspond with current literature. these results will contribute to more accurate identification of possible delays in early years of development. 43 jeanne grace affiliation: university of kwazulu natal additional authors: jeanne grace, eugene duvenage, jean pierre jordaan electrocardiographic patterns in african university strength and endurance athletes of zulu descent aim: there is concern over the effect of training on heart function of athletes as recorded by 12-lead electrocardiography (ecg). although ecg abnormalities with respect to ethnic origin of black athletes from the caribbean, west africa and east africa have been reported, black athletes from southern africa, specifically participating in different sports, have never been investigated before. the purpose of this study was to analyse the ecg patterns in south african students of zulu descent, who represented our university in boxing (endurance modality) and body building (resistance modality) at a regional level. methods: fifteen subjects each were assigned to an endurance (e), resistance (r) or control (c) group, respectively. ecg patterns were recorded with a 12-lead ecg. results: our subjects indicated no significant differences in ecg patterns in relation to whether they participate in strength or endurance related sport. however, 80% of the endurance group and 67% of the resistance displayed ecg criteria indicative of left ventricular hypertrophy (lvh), group e displays higher r5/s1-wave voltages (e = 43.3 mm; r = 36.8 mm; c = 37.1 mm) as well distinctly abnormal ecg patterns (e = 87%; r = 73%; c = 53%), raising clinical suspicion of structural heart disease. our cohort presented with non-significant, marked st-segment elevation (53% of both the e and r groups) and inverted t-waves in 27% of the e group. conclusion: similar to findings in other ethnic africans, a large proportion of our zulu study population displayed ecg criteria indicative of lvh on the evidence of a marked increase of r5/s1-wave voltage and st/t-segment changes with no differences in relation to whether they participate in strength or endurance related sport. cc grant affiliation: section sports medicine, university of pretoria additional authors: cc grant, dj dowson, helen bayne groin injuries in south african elite football players introduction/aim: a previous groin injury is a known risk factor for sustaining a future injury. the aim of this study was to investigate differences in hip strength, hip range of motion and agility between players with and without a history of groin injury. additional data was also used to create and overall impression of prevalence, time off from play, injuries sustained and treatment received. method: thirty elite male football players were tested using the hagos (hip and groin outcome score) questionnaire, isokinetic hip flexion/extension strength, adductor squeeze test, range of motion and an agility test. results: seventeen players (56.7%) gave a history of a previous groin injury and thirteen players were part of the control group. the study confirmed the hagos as a reliable measure of hip/groin disability outcome and injury status. there were no significant differences in hip flexion/extension isokinetic strength, hip range of motion, adductor strength and agility between the two groups. 35.3% of players sustained an adductor strain. 29.4% of players did not seek treatment from a qualified professional i.e. no specific diagnosis made. 23.5% sustained an inguinal rupture, 5.9% sustained a hip joint injury and 5.9% had chronic groin pain. only 5.9% of players consulted a sports physician, 64.7% of players consulted a physiotherapist. the average time off from play was 25 days. conclusion: the prevalence of groin injuries in elite football is very high, with lengthy off field time. a large proportion of players (29.4%) did not consult a qualified practitioner with their injuries resulting in inadequate rehabilitation. perhaps the best way to avoid future injuries is educating players/coaches to seek correct professional help. cc grant affiliation: section sports medicine, faculty of health science, university of pretoria additional authors: cc grant, a jansen van rensburg evidence-based prescription for cyclo-oxygenase-2 inhibitors in sports injuries introduction: healthcare professionals are increasingly under pressure to return athletes to play in the shortest possible time. there is limited choice in providing treatment that speeds up tissue repair, while simultaneously maintaining good quality of healing. inflammation forms a fundamental part in the process of tissue repair. discussion: however, excessive inflammation may cause more pain, and limit functional restoration. although the use of anti-inflammatory treatment in the form of a cyclo-oxygenase-2 inhibitor (coxibs) has been widely recognised as being effective, the potential detrimental effect on tissue repair, as described mainly in animal model studies, needs to be taken into account. the side-effects profile on the gastrointestinal tract favour coxibs over non-traditional nsaids. the possible effects on the renal and cardiovascular systems also need to be considered. the prescription of coxibs should be pathology and situation specific. conclusion: there are no clear guidelines on the correct time of administration and the duration of the course, but it seems that the literature is in agreement that they should be administered for a limited time at the lowest effective dose possible. 44 cc grant affiliation: section sports medicine, university of pretoria additional authors: e minnaar, cc grant physical activity of children from a rural town, south africa introduction/aim: lowand middle-income countries, including south africa, are witnessing the fastest rise in overweight children. the main reason identified is inactivity. the study aim was to determine the physical activity measured in boys and girls, from three different age groups, living in rural south africa. the influence of bmi, gender and age on activity measurements was also investigated. methods: seventy-eight rural children, divided in three groups according to their age, were issued a pedometer for seven days. the mann-whitney 2-tailed test was used to assess gender differences. linear regression analyses were performed to determine the role of the predictors (bmi, gender and age) on the pedometer-measured dependent variables. results: between 12-14 years boys gave 18.2% more steps than girls (p=0.042). boys between 9 and11 years gave 26.5% more steps than girls (p=0.003), and 5-6 year old boys (although not statistically significant; p=0.481), gave 11.9% more steps per day than girls of the same age. the regression model including bmi, gender and age can explain moderate to large portions of variance in average total steps (r2=0.119; p=0.024), calories (r2=0.402; p<0.001), distance (r2=0.333; p<0.001) and fat burned (r2=0.398; p<0.001), but not in aerobic steps count (p=0.153) and aerobic walk time (p=0.135). discussion/conclusion: older boys were more active than the older girls and physical activity levels differ between different age groups. activity increased for both boys and girls from the age between 5 and 6, to the age between 9 and 11. however, this was followed by a significant decrease in physical activity for ages between 12 and 14. gender and age influences the activity of children. the age group 9 to 11 may be the ideal time to focus gender specific intervention programs to prevent the significant decrease in activity during the ages of 12 to 14 and to promote a lifestyle of high physical activity. andrew green affiliation: biomechanics laboratory, school of physiology, university of the witwatersrand, johannesburg additional authors: andrew green, chloe dafkin, benita olivier, samantha kerr, warrick mckinon the trade-off between distance and accuracy in the rugby union place kick kicking is a ballistic movement that requires controlled and intricate coordination between the segments of the lower body, both temporally and spatially thereby making it a complex biomechanical action. little attention has been given to the rugby union place kick, especially in the outdoor setting. the kicker must have the ability to kick the ball long distances as well as be accurate enough to get the ball through the up-rights, spaced 5.6m apart. the success of a place kick is currently thought to be reliant on both physiological factors such as balance and strength and on biomechanical skill, such as the optimization of the kinetic chain. the study aim was to test the relationships between distance, accuracy and the kinematics of place kicking performance of rugby players in an outdoor setting. twelve first team university rugby players (age 22 ± 3 years, mass 88.73 ± 12.38 kg, stature 179 ± 6 cm, playing experience 11 ± 4 years) had fully body kinematics measured for five place kicks. all kinematics were recorded at 100hz using an 18 camera system and all biomechanical variables were calculated using custom written algorithms. kick distance and accuracy were directly measured. the kick distance was defined as the length from the midpoint on the half way line to the landing position of the ball. accuracy was determined as the width error spread (standard deviation of the participants' kicks) between the landing position of the ball and the centre line. the average kick distance achieved was 45.35 ± 5.27 m, with an average accuracy spread of 5.81 ± 3.47 m2. the current study showed a positive correlation between shoulder (r=0.755) and pelvis (r=0.661) rotation, and kick distance. further positive correlations between and playing experience (r=0.596) were related to the accuracy of the kick. negative correlation between stance elbow flexion (r=-0.780), shoulder rotation (r=-0.744) and x-factor (r=-0.785) were noted for kick accuracy. place kick distance could potentially be maximized by improving shoulder and pelvic rotations and place kick accuracy could be improved by full extension of the stance arm. our data suggests that larger shoulder rotations may promote kick distance while impeding kicking accuracy. 45 henriette hammill affiliation: university of zululand additional authors: henriette hammill, nicolene smith, s'fiso thabethe the effects of acute self myofascial release (mfr) and stretching techniques on physical fitness parameters measurements were taken initially and then participants were randomly divided into four groups (control, static stretching, dynamic stretching and self mfr). during the intervention programme the various groups took part in prescribed stretching techniques under supervision of qualified technicians for an hour. baseline measurements were repeated, except for bmi and fat percentage. repeated measures using anova revealed significant differences with a number of variables: hip flexor flexibility for both legs (hffr; p=0,043; hffl; p=0,002), sit ups (su; p=0,002) and deep squat (ds; p=0,006). ancova measures revealed that there was significant improvement in sit ups (su; p=0,014) and deep squats (ds; p=0,025) in the dynamic group, compared to the control group. in conclusion, both mfr and dynamic stretches are beneficial in improving acute selected flexibility and strength parameters. dynamic stretches show a more significant improvement compared to mfr in selected flexibility and strength parameters. this information is valuable to sport participants, providing information on the ideal stretching techniques to administer before events, which can lead to an enhancement in performance and reduction in the prevalence of injuries related to partaking in physical activity by means of increased flexibility and/or rom. the objective of this study is to assess the effects of self myofascial release (mfr) techniques and different stretching techniques on physical fitness parameters on thirty (30) university students who participate in team sports. the design used in this research project was a prospective randomized controlled study where each participant was given a numeric participation code. baseline measurements were taken initially and then participants were randomly divided into four groups (control, static stretching, dynamic stretching and self mfr). during the intervention programme the various groups took part in prescribed stretching techniques under supervision of qualified technicians for an hour. baseline measurements were repeated, except for bmi and fat percentage. repeated measures using anova revealed significanrevealed significant differences with a number of variables: hip flexor flexibility for both legs (hfp=0,002), sit ups (su; p=0,002) and deep squat (ds; p=0,006). ancova measures revealed that there was significant improvement in sit ups (su; p=0,014) and deep squats (ds; p=0,025) in the dynamic group, compared to the control group. in conclusion, both mfr and dynamic stretches are beneficial in improving acute selected flexibility and strength parameters. dynamic stretches show a more significant improvement compared to mfr in selected flexibility and strength parameters. this information is valuable to sport participants, providing information on the ideal stretching techniques to administer before events, which can lead to an enhancement in performance and reduction in the prevalence of injuries related to partaking in physical activity by means of increased flexibility and/or romthe objective of this study is to assess the effects of self myofascial release (mfr) techniques and different stretching techniques on physical fitness parameters on thirty (30) university students who participate in team sports. the design used in this research project was a prospective randomized controlled study where each participant was given a numeric participation code. baseline measurements were taken initially and then participants were randomly divided into four groups (control, static stretching, dynamic stretching and self mfr). during the intervention programme the various groups took part in prescribed stretching techniques under supervision of qualified technicians for an hour. baseline measurements were repeated, except for bmi and fat percentage. repeated measures using anova revealed significant differences with a number of variables: hip flexor flexibility for both legs (hffr; p=0,043; hffl; p=0,002), sit ups (su; p=0,002) and deep squat (ds; p=0,006). ancova measures revealed that there was significant improvement in sit ups (su; p=0,014) and deep squats (ds; p=0,025) in the dynamic group, compared to the control group. in conclusion, both mfr and dynamic stretches are beneficial in improving acute selected flexibility and strength parameters. dynamic stretches show a more significant improvement compared to mfr in selected flexibility and strength parameters. this information is valuable to sport participants, providing information on the ideal stretching techniques to administer before events, which can lead to an enhancement in performance and reduction in the prevalence of injuries related to partaking in physical activity by means of increased flexibility and/or rom ernest hobbs affiliation: high performance centre, university of pretoria additional authors: ernest hobbs, helen bayne foot and ankle kinematics in male and female adolecent endurance runners introduction: research has provided a wealth of information regarding lower leg kinematics in adult endurance runners [1, 2, 3]. the aim of the current study was to investigate foot and ankle kinematics in adolescent endurance runners, and to investigate differences between males and females. methods: twenty endurance runners (6 males, 14 females), aged 15 – 18 years, undertook a 5 minute run at approximately 90% of their training pace, at either 10.5 km/h (females) or 12 km/h (males) on a treadmill set to 0% incline. the final 20 seconds of each run was filmed at 120 hz from both the left and right side, and 60 hz from the rear. ankle dorsiflexion was measured at impact, as the angle between a line from the head of the fibula to the lateral malleolus, and the plantar surface of the outsole of the shoe. rearfoot eversion was measured at mid-stance, as the angle between the posterior midline of the lower leg and the posterior midline of the calcaneus. results: analysis of lower leg running kinematics found that rearfoot eversion was similar between males (7.0° ± 1.6 and 9.2° ± 2.8 for left and right respectively) and females (8.5° ± 2.9 and 8.6° ± 2.9 for left and right respectively), however ankle dorsiflexion showed statistically significant differences for the right foot (males: 92.0° ± 5.8, females: 85.1° ± 4.2, t = 3.02, p < 0.01) and near significant differences for the left foot (males: 89.9° ± 5.4, females: 86.0° ± 3.5, t = 1.96, p = 0.065). discussion: rearfoot eversion angles were comparable with norms from literature [1, 2, 3]. the female athletes in the current study tended to make contact in a more dorsiflexed position, which is associated with a more pronounced heel strike. this may have clinical relevance, as impact forces and injury patterns differ between footstrike patterns [4]. the influence of absolute running velocity on ankle kinematics must also be considered, and it is recommended that future studies examine changes in kinematics at varying velocities in this population. 46 erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, australia additional authors: erik hohmann, tony young, ross clark, adam bryant, peter reaburn standing balance is not an important predictor of function in acl-deficient subjects – a case control study introduction: previous research has demonstrated significant proprioceptive deficits including balance in acl-deficient knees. the purpose of this project was to investigate the use of standing balance as an indirect measure of proprioception and to investigate the relationships between balance, strength, hopping tests and subjective functional outcome scores. methods: for this project the nintendo wii balance board (nwbb) was used as a validated tool for measuring balance. twenty-seven acl-deficient subjects with a mean age of 28+9.6 (range 15 to 50) and thirty-eight control subjects with a mean age of 26.7+6.7 (range 15 to 57) were tested. single leg standing balance, isometric quadriceps strength, and isometric hamstrings strength tests were performed using the nwbb and customwritten software. all subjects performed single leg hops and vertical jumps, and completed lysholm and ikdc questionnaires. results: statistical analysis comparing control and acl-deficient groups revealed significant between group differences for standing balance (p=0.02), quadriceps strength (p=0.006), hop (p<0.0001), vertical jump (p=0.02), and lysholm score (p<0.0001). however multivariate analysis within the acl-deficient group demonstrated no significant relationships between variables. conclusions: the results of this study suggest that while there are significant differences between the healthy acl-intact subjects and the acldeficient group in all variables, standing balance is not an important predictor of subjective function in the acl-deficient group. erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, australia additional authors: erik hohmann, kevin tetsworth large osteochondral lesions of the femoral condyles: treatment with fresh frozen and irradiated allograft using the mega oats technique purpose: fresh and fresh frozen allograft has been used by many surgeons as a viable and effective treatment for large osteochondral lesions of the femoral condyles. irradiated allograft transplantation may be an alternative option and result in similar clinical outcome. the purpose of this study was to review the clinical results of irradiated fresh frozen osteochondral allografts for large osteochondral defects of the knee using the mega-oats technique. methods: a total of nine patients (5 males, 4 females) with a mean age of 32.1+6.6 (18-44) underwent mega-oats transplantation with irradiated (2.5mrad), fresh frozen distal femur allograft. three patients underwent acl-reconstruction; one patient a high tibial osteotomy. the underlying cause was osteochondrosis dissecans in four and trauma in five patients. the defect size was 25x25 mm in three patients and 30x30 in six patients. all ocd lesions were located on the medial femoral condyle; two of the traumatic lesions were located on the lateral femoral condyle. clinical outcome was assessed by using the lysholm and ikdc scores. radiographic incorporation was evaluated using serial radiographs and mr imaging at one year post surgery. all patients were reviewed at 3,6,12, and 24 months following surgery. results: the lysholm score improved significantly (f=69.9, p=0.02) within and between patients during the follow-up period from 40.9 to 90.9 at 2 years. the ikdc score also improved significantly (f=118, p=0.007) within and between patients during the follow-up period from 37 to 87.1 at 2 years. radiographic union was observed in all patients at three months; on mr imaging at one year osseous integration was observed in 8 patients. graft subsidence with loss of the overlying cartilage was observed in one and subchondral cystic changes at the implantation side was seen on another patient. conclusion: the results of this small case series suggest that irradiated osteochondral allograft provides significant medium-term clinical improvement in patients treated for large osteochondral lesions of the femoral condyles. erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, australia additional authors: erik hohmann, cariad wratten, kevin tetsworth comparison of three-dimensional between gender femoral notch volume in acl-deficient versus acl-intact subjects purpose: the purpose of this study was to evaluate between-gender differences in three-dimensional femoral notch volume in anterior cruciate ligament (acl)-deficient patients compared to a matched control group of acl-intact patients. methods: magnetic resonance images from 90 acl-deficient subjects (45 males, 45 females) aged 16-50 years were identified from our departmental database, and then compared to a matched control group of acl-intact subjects. the three-dimensional femoral notch volume on each mri was measured using software specific tools. one-way anova was used to compare notch volume between acl-deficient and acl-intact groups and between the two genders. the relationships between height, weight, bmi and notch volume for each group and within the male and female cohort were established using pearson's moment correlations. results: femoral notch volume in the female acl-deficient group was 3.1 ± 0.70 cm3 (ci ±0.2) compared with 3.6 ± 0.7 cm3 (ci ± 0.2) in the female control group. notch volume in the male acl-deficient group was 4.5 ± 1.1 cm3 (ci ± 0.3) compared to 5.3 ± 1.2 cm3 (ci ± 0.4) in the male control group. there were significant differences between the male acl-deficient and acl-intact group (p=0.02), the female acl-deficient and acl-intact group (p=0.0002), the acl-deficient male and female groups (p <0.0001), and between the male and female acl-intact groups (p <0.0001). there were weak and nonsignificant relationships (r=0.01-0.37) between height, weight, bmi and notch volume between groups and within the male and female cohort. conclusions: these results clearly demonstrate a decreased femoral notch volume as measured on three-dimensional-mri in acl-deficient patients. there were highly significant differences in femoral notch volume between male and female cohorts, as well as between acl-deficient and acl-intact subjects of both genders. 47 erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, australia additional authors: erik hohmann, krishna kumar, ancy thomas, kevin tetsworth short-term benefit from an intra-articular steroid injection in patients with adhesive capsulitis of the shoulder treated with physiotherapy? purpose: the purpose of this retrospective study was to investigate the possible short-term benefit of a single intra-articular corticosteroid injection in those patients treated with physiotherapy when compared to a group of patients undergoing physiotherapy only. methods: a retrospective chart review was conducted to identify eligible patients treated over a four-year period. all female patients between 40-60 years with a confirmed clinical diagnosis of idiopathic adhesive capsulitis who completed a prescribed physiotherapy program between 2006 and 2009 were considered eligible. sixty-three patients fulfilled the inclusion criteria, but 22 were excluded because of missing data in the medical record. the remaining 41 patients comprise the study cohort; an experienced musculoskeletal physiotherapist assessed these patients both at initial presentation and at 12 weeks. twenty patients with a mean age of 55.1 years underwent physiotherapy only (pt only) and 21 patients with a mean age of 52.4 years received a single intra-articular dose of 40 mg methylprednisolone followed by physiotherapy. outcome measures included the visual analogue scale (vas) and measurement of range of motion. results: at final assessment (12 weeks), significant between group differences were identified for the “pt only” group for flexion (p=0.01) and abduction (p=0.008). when comparing the mean change from the initial assessment, a significant between group difference was observed for abduction (p=0.03). conclusions: the results of this study suggest that the intra-articular injection of a single dose of cortisone has no significant short-term benefit in female patients with idiopathic adhesive capsulitis managed with physiotherapy. erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, australia additional authors: erik hohmann, kevin tetsworth, andreas imhoff plantar pressures during long distance running: an investigation of 10 marathon runners. purpose: the objective of this study was to record plantar pressures using an in-shoe measuring system before, during, and after a marathon run, and to investigate the effect of fatigue. methods: peak and mean plantar pressures were recorded before, after, and every three km during a marathon race in ten male runners using an in-shoe plantar pressure system in both feet. heart rate, serum lactate levels and the borg scale were used to assess both subjective and objective fatigue. results: there were no significant changes over time in peak and mean plantar pressures for either the dominant or non-dominant foot for all six anatomical areas measured. there were significant between dominant and non-dominant foot peak and mean plantar pressure differences for the total foot (p=0.0001), forefoot (p=0.0001), midfoot (p=0.02 resp. p=0.006), hindfoot (p=0.0001), first ray (p=0.01 resp. p=0.0001) and mtp (p=0.05 resp. p=0.0001). conclusions: long-distance runners do not demonstrate significant changes in mean or peak plantar foot pressures over the distance of a marathon race, for either the dominant or non-dominant foot. however, athletes consistently favoured their dominant extremity, applying significantly higher plantar pressures through their dominant foot over the entire marathon distance. erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, australia additional authors: erik hohmann, kevin tetsworth, peter reaburn, andreas imhoff runners' knowledge of their foot type: do they really know? purpose: the use of correct individually-selected running shoes may reduce the incidence of running injuries. however, the runner needs to be aware of their foot anatomy to ensure the “correct” footwear is chosen. the purpose of this study was to compare the individual runner's knowledge of their arch type to the arch index derived from a static footprint. methods: we examined 92 recreational runners with a mean age of 35.4+11.4 (12-63) years. a questionnaire was used to investigate the knowledge of the runners about arch height and overpronation. a clinical examination was undertaken using defined criteria and the arch index was analysed using weight-bearing footprints. results: forty-five runners (49%) identified their foot arch correctly. eighteen of the 41 flatarched runners (44%) identified their arch correctly. twenty-four of the 48 normal-arched athletes (50%) identified their arch correctly. three subjects with a high arch identified their arch correctly. thirty-eight runners assessed themselves as overpronators; only four (11%) of these athletes were positively identified. of the 34 athletes who did not categorize themselves as overpronators, four runners (12%) had clinical overpronation. conclusion: the findings of this research suggest that runners possess poor knowledge of both their foot arch and dynamic pronation. 48 erik hohmann affiliation: musculoskeletal research unit, cq university, australia medical school university of queensland, australia additional authors: erik hohmann, adam bryant, robert newton, julie steele can we predict knee functionality of acl deficient and acl reconstructed patients using tibial acceleration profiles? purpose: during abrupt deceleration tasks, tibial acceleration is indicative of tibial stability and shock transmitted through the lower limb. the purpose of this study was to examine relationships between knee functionality and tibial acceleration of acl deficient and acl reconstructed patients during landing from a single-leg long hop. methods: knee functionality was rated using the cincinnati knee rating system for the involved limb of 10 chronic, functional acl deficient patients and 27 acl reconstructed patient (14 using a patella tendon (pt) graft and 13 using a semitendinosus/gracilis tendon (stgt) graft). tibial acceleration during a single-leg long hop was assessed using a uniaxial accelerometer attached to the tibial tuberosity of each patient's involved limb. results: pearson product moment correlations revealed a significant (p < 0.05) moderate negative relationship between knee functionality and time to zero tibial acceleration in the acl deficient patients (r = -0.58), indicating patients who minimised the time of positive tibial acceleration had higher levels of knee functionality. for the pt graft group, a significant moderate negative relationship (r = -0.55) between knee function and time to peak tibial acceleration was found indicating that early control of peak tibial acceleration was a determining factor following reconstruction using the pt. no significant relationships were found between knee functionality and tibial acceleration for the stgt graft patients. conclusions: the relationships between knee functionality and tibial acceleration suggested that those patients who were better able to arrest acceleration of the tibia during an abrupt deceleration task, whether reconstructed or not, tended to display greater knee functionality. erik hohmann affiliation: musculoskeletal research unit, cq university, australia; school of medicine, university of queensland, australia additional authors: erik hohmann, joyce anthony, kevin tetsworth the influence of the labrum on osseous version and diameter a glenoid morphometric study using mr arthrograms introduction: morphometric variables of the glenohumeral joint such as glenoid version and diameter have been associated with glenohumeral instability, rotator cuff tears, osteoarthritis and the success of total shoulder arthroplasty. although widely accepted that the labrum increases the contact area between the humeral head and scapula, its influence on version is not well understood. the purpose of this study was to determine the influence of the labrum on osseous version and diameter of the glenohumeral joint. methods: this is a radiological, cross-sectional study of the glenoid labral and osseous version and diameter measured on mr arthrograms that were void of glenohumeral joint pathology as determined by an independent radiologist. patients where scanned using the siemens magnetom verio 3t mri scanners and variables measured using intellispace pacs enterprise. these variables were measured by two independent investigators. images of the first 20 patients were used to determine interand intra-observer reliability (icc). icc demonstrated excellent interand intra-rater reliability (0.956 resp. 0.938) resulting in these variables being measured for all patients by a single observer. statistical analysis involved descriptive analysis of measured variables and paired student t-tests to determine the difference between labral and osseous variables. results: 100 patient arthrograms were studied with an even site (m=49, f=51) and gender (r=56, l=44) distribution. patients demonstrated a mean age of 22.2 years (sd=4.5), glenoid osseous version of -5.7 deg (sd=5.3), labral version of -10.0 deg (sd=5.5), osseous diameter of 28.1mm (sd=3.3) and labral diameter of 31.967mm (sd=3.175). inferential analysis using paired student t-tests demonstrated that glenoid labrum significantly (p=0.001) increased retroversion by 4.3 deg and diameter by 3.9 mm (p=0.001). conclusion: this study demonstrated significant increases in glenoid version and glenoid diameter. given these findings it may be more important to create a “bump” when repairing the labrum in order to preserve or increase retroversion rather than a simple repair to preserve the contact area. audrey jansen van rensburg affiliation: section sports medicine, university of pretoria additional authors: audrey jansen van rensburg, dc janse van rensburg the use of negative pressure wave treatment in athlete recovery regeneration and recovery is vital for maximising athlete performance in competitive sport. lower body negative pressure (lbnp) treatment originally developed for astronauts to maintain orthostatic balance, proved substantial in clinical application improving circulation in complex wounds. intermittent vacuum therapy may enhance blood flow throughout the entire body, possibly rejuvenating and improving the impaired physical state of injured or exhausted athletes. 22 male cricket players completed a 1-hour power gym session. randomly divided, the treatment group received three 30 minute lbnp exposure sessions over three consecutive days (0, 24 and 48 hours); the control group received no treatment. after 14 days groups were crossed over and the trial repeated. to determine the acute therapeutic effect, participants continued their regular coaching and competition program. heart rate and blood pressure decreased noticeably during treatment, reverting to baseline levels after treatment. lactate concentrations decreased in both groups after exercise termination; significantly more in the treatment than control group (0.57±0.23 vs. 0.78±0.22, respectively, p<0.001). creatine kinase (ck) indicated no significant decrease. athletes' personal perceived degree of regeneration rated moderately high. lbnp therapy may have a systemic effect in lowering serum lactate levels, but not ck levels. enhanced regeneration and recovery of athletes are still unconfirmed. robert jones affiliation: rhodes university additional authors: robert jones, andrew todd, candice christie ethnicity: a key risk factor for hamstring injury ethnicity has been identified as a key risk factor for hamstring injuries in intermittent sports. when compared to their caucasian counterparts, epidemiological studies indicate professional players of black african ethnic origin to be at an increased risk of hamstring muscle strain in australian rules football, rugby union and soccer. anthropometric, biomechanical and physiological differences between caucasian and black african players may influence muscular fatigue responses, increasing the risk of strain injuries in the hamstring musculature. while possessing similar vo2max values to caucasians athletes, black african runners elicit a higher fractional vo2max utilisation, a superior running economy, as well as a greater predominance of type ii muscle fibers. these distinctive features limit the applicability of research on caucasians to players of black african ethnicity. this is further complicated by intra-ethnic variations in muscle fiber distribution among individuals from different geographical locations within africa (north, south, east, west africa). muscle phenotype characteristics are thought to influence the risk of hamstring injuries. players with a greater proportion of type ii fibers are more susceptible to hamstring fatigue induced by eccentric loading during the maintenance of the intermittent activity profile. due to a predominance of type ii fibers, black african players are suggested to be at a greater risk of hamstring strain injury as these players experience greater eccentric hamstring muscle fatigue during match-play compared to caucasian players. in this review, these factors are explored as they have important implications when designing and implementing training and recovery programs for black african players. 49 jessica köhne affiliation: university of kwazulu natal additional authors: jessica köhne, michael j. ormsbee, andrew j. mckune the impact of a multi-ingredient supplement on markers of muscle damage and inflammation following downhill running in female athletes exercise-induced muscle damage (eimd) can result in reduced muscle force, increased muscle soreness, increased intramuscular proteins in the blood, and reduced performance. single ingredient supplementation protocols with whey protein isolate, branched-chain amino acids (bcaas), creatine, and caffeine have been used to reduce the effects of eimd. however, little is known about the effects of a multi-ingredient supplement on the reduction of muscle damage and repair after eimd from downhill running. moreover, there is little known about the effects of performance supplementation on endurance trained female athletes. aim: the purpose of this study was to investigate the potential effects of the ingestion of a multi-ingredient supplement on markers of muscle damage and inflammation following a single 60 minute bout of downhill running (dhr) in trained female runners. methods: eight female runners were matched by vo2max (≥ 50 ml-1.kg-1.min-1) and menstrual cycle, and randomly assigned in a double-blind manner to consume a 28g multi-ingredient supplement (no shotgun) (n=4, 28.5 ± 6.5 yrs, 1.66 ± 0.06 m, 57.06 ± 3 kg) or 28g isocaloric flavourmatched placebo (maltodextrin) (n=4, 29.5 ± 5.12 yrs, 1.60 ± 0.06 m, 56.40 ± 4.7 kg) daily for four weeks pre-dhr. all participants were premenopausal, and all participants were be tested as close as possible to the mid-follicular phase (7-11 days after menses) of the menstrual cycle similar to the seven day inactive (or placebo) phase of hormonal contraceptive therapy. participants performed a dhr after 4 weeks of supplementation, at a speed equivalent to 75% vo2max at -10% gradient. serum creatine kinase (ck), interleukin-6 (il-6), and c-reactive protein (crp) were collected prior to dhr, immediately post-, 24 hours, 48 hours, and 72 hours post-dhr, with power output, hamstring flexibility, and muscle pain perception measurements taken at the same time points. results: there were no significant group x time differences, but there was a main effect of time for ck (p=0.05), pain perception (vas) (p=0.068), lower-limb muscle pain, and maximum squat jump power (p=0.043). crp peaked at 24 hours post-dhr and il-6 peaked immediately post-dhr, with crp decreasing at 48hrs post-dhr (-5.44% of baseline). serum ck increased by 14.23% from baseline to 24 hours post-dhr, decreased back to baseline by 48 hours. the vas measures showed a significant 13-fold increase from baseline to 24 hours post-dhr (p=0.019), and an 11fold increase from baseline to 48 hours (p=0.022). conclusion: multi-ingredient supplementation did not reduce muscle damage and inflammation compared with an isocaloric placebo, although the bout of dhr did elicit changes in muscle damage and inflammatory markers in trained female runners that were returned to baseline by 72 hours. david lee affiliation: griffith university, griffith university centre for musculoskeletal research, menzies health institute additional authors: david lee, david saxby, prof rod barrett, dr richard newsham-west, dr michael ryan repeatability and agreement of digital image correlation (dic) for regional strain estimates of the in-vivo human patellar tendon introduction: strain is an essential measure of tendon tissue mechanics, with distribution during functional loads helping to identify damaged or pathological regions and quantifying possible functional compromise. dic is a non-contact image processing method that applies a correlation function to features in successive ultrasound images to estimate strain under dynamic and high-load conditions within an identified region of interest. the primary aim of this study was to assess the methodology of applying dic to estimating localised strain behaviour of the patellar tendon. specifically this study assessed 1) between-trial and between-day repeatability; and 2) the level of agreement of the dic estimates with an accepted manual point-to-point method. methods: seven adult subjects (5 males, 2 females; age = 30.5 +/3.5 y) performed a rate controlled voluntary ramped contraction to a normalised target torque over a specified rate with simultaneous collection of sagittal plane imaging of the patellar tendon and knee extensor torque using real time b-mode ultrasonography and dynamometry, respectively. transducer position and displacement during contractions were tracked by a 3d vicon motion capture system. recorded ultrasound images were subsequently processed using specialized software to estimate strain at selected regions. results: intraclass correlation values for between-trial and between-day strain estimates were greater than 0.86 (p<0.95). the coefficient of variation of the root-mean-square difference (p<0.95) and average mean detectable change (p<0.95) for dic estimates were 1.06% (0.9-1.23%) and 0.19% (0.15-0.23%) and 0.69% and 1.69%, respectively. limits of agreement analysis reported there was a 95% likelihood that dic values were within ± 1.03% of the manual method. dic was found to overestimate reported strain by 0.28%. intraclass correlation values for betweensession transducer position (p<0.95) were greater than 0.86. mean transducer displacement during contractions was found to be 6.97mm (+/ 3.69mm). conclusion: results show dic to be a feasible and repeatable approach for estimation of regional strain at the patellar tendon. the accuracy and repeatability of dic did not appear to be affected by change in transducer position or rotation in this study. 50 daniel lithwick affiliation: university of british columbia, faculty of medicine additional authors: daniel lithwick, saul isserow, brett heilbron, barbara morrison, hamed nazzari, jack taunton screening young competitive athletes for underlying cardiovascular disease in british columbia, canada – a sportscardiologybc study introduction:the sudden cardiac death (scd) of a young athlete is a rare, yet tragic event. following the publication of a 25-year study out of italy that showed a 90% risk reduction for scd after the implementation of a systematic screening program, international attention towards the concept of screening has increased. implementation of screening remains a controversial issue, with the primary disparity lying in whether a 12-lead electrocardiogram (ecg) should be included in addition to a cardiovascular focused medical history and physical examination. currently canada has no official screening mandate. the purpose of this study is to determine the prevalence of cardiovascular diseases that can lead to scd in a sample of young (12-35) competitive athletes in british columbia. methods: 1,319 athletes were screened. 688 participants were evaluated using a resting 12-lead ecg (european society of cardiology recommended) and the 12-item questionnaire, inclusive of personal history, family history and physical examination, as recommended by the american heart association. a protocol amendment was made following the initial round of recruitment with the elimination of the physical exam and a revised questionnaire. as such, the following 631 participants recruited were screened with ecg and a questionnaire created by sportscardiologybc researchers and clinicians. results: of the 1,319 athletes evaluated, 98 (7.4%) required follow-up investigation. 11 cardiovascular disorders (0.8%) were found: probable hypertrophic cardiomyopathy (hcm), myxomatous mitral valve prolapse with mild regurgitation, mild-moderate tricuspid insufficiency with pectus excavatum, supraventricular tachycardia, paroxysmal supraventricular tachycardia, 4 cases of wolff-parkinson-white syndrome, long qt syndrome and a restrictive ventricular septal defect. 26 participants are still under investigation for the presence of disease – notable queries include atrial septal defect, hcm, arrhythmogenic right ventricular dysplasia, and premature coronary artery disease. conclusion: athletes in this study have yet to be restricted from activity, however 11 cases of cardiovascular diseases were identified and investigation into several more athletes is pending. as such, screening for cardiovascular disease in this population is likely a worthy endeavour. the aha 12-item questionnaire produced several false-positive results, prompting the research team to revise the screening protocol. the most feasible and effective screening protocol must still be determined. daniel lithwick affiliation: university of british columbia, faculty of medicine additional authors: daniel lithwick, saul isserow, brett heilbron, barbara morrison, hamed nazzari, jack taunton, michael luong screening young competitive athletes for underlying cardiovascular disease the sportscardiologybc protocol introduction: sportscardiologybc (scbc) has screened 1,319 young (12-35) competitive athletes across british columbia, canada with 12-lead electrocardiogram (ecg) (european society of cardiology recommended), history and physical examination (american heart association 12-item questionnaire) in order to investigate prevalence of cardiovascular disease. following recruitment of the initial 688 participants, the researchers found the questionnaire to be causing several false-positive results. further, they found that the physical examination had a low utility to detect disease, and that physician time was scarce and expensive. therefore, a new screening protocol was developed in which the physical examination was eliminated and a new questionnaire was created. the questionnaire includes positive and negative questions on symptoms in an attempt to differentiate what might be cardiac causes in the absence of a physician. methods: 688 participants were screened using ecg and the 12-item questionnaire from the aha and the following 631 participants were screened using the ecg and the scbc questionnaire. in order to determine if it may be more feasible and effective to screen large athlete populations without a physician present, the positive predictive values (ppv) of the two protocols have been calculated. results: of the first 688 participants screened, 61 (8.9%) required follow-up testing; of which 5 were confirmed to have cardiovascular disease, with 9 still undergoing investigation. in the following 631 participants screened using the scbc protocol, 37 (5.9%) required follow-up testing, of which 6 athletes were found to have cardiovascular disease, with 18 still undergoing investigation. without consideration of those still under investigation, the initial protocol yields a ppv of 9.6%, and the scbc protocol yields a ppv of 31.6%. conclusion: following the experience with the first 688 participants, the research team felt that a more feasible and effective screening protocol could be developed. based on the increased positive predictive value and lower absolute and relative number of false-positives, this was found to be correct. concerns regarding false negatives with the elimination of the physician from the screening process are valid, and as such further studies with proper ascertainment of false-negative rates must be conducted to determine sensitivity and specificity. rochelle louw affiliation: university of pretoria additional authors: rochelle louw, licinda pienaar the effect of movement instruction on muscle activation introduction: the primary objective of this study was to determine if various muscles could more successfully activated during a specific movement/exercise when receiving instruction(“kinetic precision”method or technique) as opposed to no or minimal instruction. the “kinetic precision” method included placing the body in a favourable position and using “conscious initiated muscular resistance” (mind-body connection). methods: a cross-sectional comparative design was used. twenty subjects performed six movements. the subjects performed the movements without instruction and then again, after receiving specific instructions (“kinetic precision” technique). the movements or exercises were performed while surface electromyography (emg) measurements were taken of fourteen different muscles groups. emg data was collected and analysed using the noraxon, emg & sensor systems (scottsdale, arizona) using standard emg techniques and protocols. the wilcoxon signed rank test was used to determine if there was a statistically significant (p≤0.05) difference between measurements. results: there were significant differences (p≤0.05) in terms of muscle activation between test one and test two for ten of the fourteen muscles tested using surface emg. namely, side lying gluteus maximus exercise: m. gluteus maximus (p=0.001) and m. erector spinaelumbar (p=0.027); sitting knee extension exercise: m. rectus femoris (p=0.00) and m. erector spinaelumbar (p=0.00); side lying gluteus medius exercise: m. gluteus medius (p=0.004); sitting arm flexion exercise: m. trapeziusupper (p=0.000); sitting theraband exercise: m. infraspinatus (p=0.040) and m. trapeziusmiddle (p=0.025); and supine bridge exercise: m. gluteus maximus (p=0.000) and m. biceps femoris (p=0.033). for all the significant differences, test 2 (with instruction – kinetic precision) was greater in terms of muscle activation except for the sitting arm flexion exercise: m. trapezius – upper (p=0.654); sitting theraband exercise: m. trapezius – middle (p=0.025); and supine bridge exercise: m. biceps femoris (p=0.033). discussion/conclusion: the desired effect with regards to muscle activation increasing or decreasing significantly (pë‚0.05) was achieved in eight muscles. therefore results appear favourable regarding the effects of “kinetic precision technique using conscious initiated muscular resistance” in terms of exercise form and muscle activation. further research is recommended using a larger sample and possibly comparing various instruction techniques using a cross-over design. 51 mean maddocks affiliation: university of johannesburg hallux valgus in the female ballet dancer: a literature review on risk factors background: there is little consensus about the aetiology of hallux valgus (hv), but certain risk factors are widely agreed upon. it has long been believed that dance, specifically the ballet technique of dancing en pointe, causes hv. due to very little research on the matter, the biomechanics, associated risk factors, conditions and injuries in dance are poorly understood. methodology: the university of johannesburg library, electronic databases, as well as general search engines, such as google-scholar, were searched using specific search terms. books and articles were sifted according to their content. resources that contained dance and hv were then evaluated according to key criteria: hv and dance, dancer versus non-dancers, dance biomechanics, etc. the findings obtained from the literature were then assimilated. discussion: dancers are exposed to the same risk factors as the general population: age, gender, heredity, constrictive footwear and anatomical factors like hypermobility, achilles tendon tightness, pes planus, to name a few. dancers, however, have some risk factors that are unique to them: dance itself, poor technique and, notoriously, the shoewear, specifically the pointe shoe which enables a dancer to stand and dance on the tips of her toes. this literature review found that even though dance is associated with hv, the pointe shoe, and the ballet technique is only a risk factor for hv, not a conclusive cause. in more recent studies, features that were once believed to be associated with hv in dancers, are not. these include hours of dancing and hours of dancing en pointe per week, age at which pointe work was started and totally years on point. akshai mansingh affiliation: university of the west indies . posterior ankle impingement in fast bowlers introduction: ankle injuries in fast bowlers in cricket are common and can be acute or chronic in nature. posterior ankle impingement is a collection of chronic conditions caused by repetitive forced dorsiflexion as well as plantar flexion. it is being reported increasingly in fast bowlers and is often associated with a large os trigonum. this study of posterior ankle impingement in west indian fast bowlers looks at clinical features in presentation and findings, and proposes treatment options. factors influencing treatment will be discussed methods: a retrospective analysis of ankle impingement injuries treated in fast bowlers in the west indies was conducted between 2005 and 2014. duration and features of presentation were noted as well as investigation findings. treatment effected was reviewed as well as the outcome. results: seven fast bowlers had evidence of os trigonum in the front foot only. pain was felt on forced plantar flexion and dorsiflexion on front foot landing; no pain was felt with running. four had large os trigonum on radiographs, and one was detected only by mri. three bowlers with low workloads resolved with steroid injections. the remainder had surgical excision which led to recovery. conclusion: this injury is being seen increasingly in fast bowlers. steroid injections are useful in bowlers with low workloads, but surgical excision is recommended in bowlers with heavy workloads. further investigation is required in biomechanics of bowling to determine the cause for the increase in this condition. robroy martin affiliation: duquesne university additional authors: robroy martin, hal martin, ricardo schrã¶der management of deep gluteal syndrome a case series introduction: while deep gluteal syndrome (dgs) is becoming increasingly recognized, there is little information to guide the management of patients diagnosed with dgs. a positive outcome of those with dgs may require a comprehensive multi-professional treatment approach. the current study describes an algorithm for management of individuals with dgs and includes physical therapy, psychological counseling, intramuscular computed tomography (ct)-guided injection, and endoscopic surgery. material & methods:the cases series was conducted between april 2014 and december 2015. study population was composed of subjects diagnosed with deep gluteal pain through a detailed history, physical examination, imaging and diagnostic testing. six female subjects were treated during an average time of 20 weeks (6-36 weeks). visual analog scale, modified harris hip score, and patient satisfaction were used to describe outcomes. physical examination was used to determine appropriate physical therapy interventions. specifically, interventions were directed at lumbopelvic, hip intra-articular, hip extra-articular, and/or pelvic floor structures with neuromuscular retraining, soft tissue length-tension rebalancing, joint mobilization, soft tissue mobilization, and/or neural mobilization as indicated. neuropsychiatry evaluation was used to determine appropriate psychological counseling techniques to address issues associated with anxiety and depression. intra-muscular injections through ct guidance in the piriformis and/or obturator muscles were used in cases that did not have satisfactory results after physical therapy and psychological counseling. subjects who found temporary benefit from injections were considered candidates for endoscopic surgery. results: the deep gluteal pain was identified as a chronic condition associated with factors such as low back pain, presence of hip intra-articular pathology, previous pelvic surgery, urogynecological and psychological influences. when appropriately managed improvement was obtained in the subjects included in this study within an average time of 20 weeks (6-36 weeks). discussion & conclusion: patients with dgs can have a good outcome when the algorithm for appropriate management is applied. thorough diagnostic work-up was found to be the best method to determine the most effective treatment. conservative management should consist of a multiprofessional treatment approach with neuromuscular retraining, soft tissue length-tension rebalancing, joint mobilization, soft tissue mobilization, neural mobilization, psychological counseling, and/or intra-muscular injections as indicated through the comprehensive evaluation. 52 sarah j moss affiliation: north-west university additional authors: sarah j moss, tamrin veldsman effect of a long-term physical activity intervention on risk factors for coronary heart disease in adults with intellectual disability background: physical inactivity is a major risk factor for developing coronary heart disease (chd) in persons with an intellectual disability (id). longevity of individuals with an id can be ameliorated by decreasing the risk for chd with increased physical activity. limited research is available on long-term physical activity intervention in persons with id therefore; the aim of this study is to determine the effect of a long-term physical activity intervention programme on risk factors for chd. methods: a cohort of 74 participants living in a care facility in potchefstroom, north west province of south africa, gave consent for participation in this seven-year follow-up study. the participants aged chronologically between 25 and 76 years were intellectually aged between 4 and 12 years. the chd risk factors were determined by means of questionnaire and physical assessment of resting blood pressure, body mass index (bmi), fat percentage and non-fasting glucose and cholesterol measurements. the long-term physical activity intervention included two weekly supervised aerobic and resistance training activities for health improvement. ancova with adjustment for baseline were performed as well as the mcnemar exact test for preto post-intervention changes in risk factor variables and point prevalence of risk factors. results: the point prevalence of inactivity in the participation decreased from 50% to 24%. total cholesterol prevalence risk factor increased from 23% to 45%. prevalence of age as a risk for developing chd increased significantly in the seven-year follow-up study from a 10% prevalence to 28%. body mass decreased significantly in men (1.25 ± 5.43 kg) and increased significantly in women (0.15 ± 6.83 kg). bmi reflected the changes in body mass for men and women respectively. body fat percentages in men (2.98%) and in women (0.95%) increased. a significant increase in systolic blood pressure (sbp) for men (6.2 ± 18.1 mmhg) and diastolic blood pressure (dbp) for women (6.35 ±10.42 mmhg) was determined. in women total cholesterol increased significantly (0.53 ± 0.41 mmol/l). conclusion: a long-term physical activity intervention in a population with id reduced the point prevalence of inactivity, while total cholesterol increased. arline muller affiliation: unizulu additional authors: arline muller, henriette hammill the effect of pilates and progressive muscle relaxation therapy (mrt) on stress and anxiety during pregnancy: a literature review aim: to compile a structured literature review pertaining to the effect of pilates and progressive muscle relaxation therapy (mrt) on stress and anxiety during pregnancy. methods: a literature search from 2005-2015 was conducted in order to capture all the articles applicable to the effects of pilates and progressive mrt on stress and anxiety during pregnancy. a descriptive analysis was undertaken of those articles that met the established criteria for inclusion following the search. results: searches from the databases identified 4475 articles, of these, 4461 articles were excluded and 14 articles were ultimately included for review. conclusion: additional research into this topic is necessary due to the limited number of papers that are published especially concerning the psychological and physiological effects of pilates during pregnancy. the literature on progressive mrt during pregnancy is better documented. the findings of this systematic review indicate that there is strong evidence that progressive mrt is an effective method in reducing stress and anxiety during pregnancy. key words: pregnancy, pilates, progressive muscle relaxation therapy, stress, anxiety. stacy nellemann affiliation: rhodes university additional authors: stacy nellemann, candice christie, jonathan davy a laboratory simulated investigation into the impact of sunglass tint on the catching performance of fielders during cricket introduction: vision is particularly important for the successful execution of goal directed actions in sport. in order to accomplish this, spatial and temporal information provided by the eyes to the brain, results in the perception of the surrounding environment. in sport played outdoors, vision is further impacted by exposure to harmful uv radiation from the sun affecting ocular health, ultimately affecting the quality of vision. consequently outdoor athletes like cricketers, who are the focus of this study, use sunglasses to prevent this from occurring. in addition, the tint of sunglasses purportedly provides performance-enhancing benefits such as contrast enhancement based on the colour of the lens. despite these purported benefits, no research has established the efficacy of different colour tints of lenses. the primary objective of this study therefore is to investigate how catching performance of cricketers, is affected by different colour tints of sunglasses methods: in order to investigate the effect four different colour tints of sunglass (clear, red, grey and blue) affect catching when fielding in cricket, a within subjects, repeated measures design was used. players were pre-screened for eligibility and required to be cricket players between the ages of 18-30yrs with a minimum of 5 years playing experience, no ocular deficiencies and be non-habitual sunglass wearers. during the pre-screening examination, objective ocular measures of contrast sensitivity, stereopsis and visual acuity were taken. eligible players partook in four experimental sessions, which were randomised. prior to each session, players were habituated wearing the selected tinted lens by catching 12 balls projected with a bowling machine. following habituation players were required to catch 30 balls projected at a speed of 26m.s-1 (93km.h-1) with an inter-delivery time of 32s. the quality of each catch was retrospectively graded using wickstrom's catching performance scale and the absolute number of catches made recorded. in the last experimental session, participants completed a questionnaire to investigate subjective opinion of performance comparing the different lenses. the findings will be clinically relevant not only to opticians but also to those interested in enhancing performance results: data is currently being collected therefore will be analysed and presented at the conference. 53 natalia neophytou affiliation: centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa additional authors: natalia neophytou, kerith d aginsky, kirsten keen, the comparison of change of transversus abdominis muscle thickness and plank holding time in club cricket players background: research between bridge holding time as an indication of core stability, by means of measuring transverse abdominis (ta) muscle function is limited. objective: a correlation study comparing ta muscle function and bridge holding time in club cricketers. methods: seventeen male, premier league cricketers (age: 22.1 ± 3.3 years) participated. visual ultrasound measured bilateral ta, internal oblique (oi) and external oblique (oe) muscle thickness at rest and during abdominal hollowing. muscle function was measured as the change in muscle thickness from rest to abdominal hollowing and compared to holding time of the supine and prone bridges (seconds) by means of a pearson's correlation. results: ta muscle thickness was preferentially recruited bilaterally (p=0.0000). no significant correlations existed between ta muscle function and supine or prone bridge holding time. negative correlations were found between prone bridge and nd ta muscle thickness at rest (r= -0.57, p= 0.017) and abdominal hollowing (r= -0.54, p=0.03); and supine bridge with d and nd oe at rest (d: r = -0.52; p = 0.04; nd: r = -0.60; p = 0.01) and abdominal hollowing (d: r = -0.55, p = 0.03; nd: r = -0.54, p = 0.03). conclusion: prone and supine bridge holding times are not correlated with ta muscle function. natalia neophytou affiliation: centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa additional authors: natalia neophytou, estelle watson, justin jeffrey, amy bedford, craig eliasov, demitri constantinou the use of ekso bionicstm exoskeleton as a rehabilitation tool in patients with spinal cord injuries: a case study series background: major advances in robotic technology have led to the development of various types of walking devices used for locomotor training.[3,4] one such device was famously used during the 2014 fifa world cup tm to kick the first ball of the tournament.[5] these various devices, although inspiring and encouraging for people living with paralysis, are very much in the early stages of development, and more evidence and practical information is required if clinicians are to safely use them as rehabilitative tools. objective: an exploratory study investigating the exoskeleton as a rehabilitation tool in spinal cord injury patients. methods: standardised baseline measurements were taken pre and post intervention for 3 spinal cord injury participants. the participants underwent 10 sessions of locomotive training using the ekso™ exoskeleton device over a 5 week period. an 80% compliance rate was required in order to complete the study. pre and post measures included: calf circumference, resting blood pressure and the he rand 36 item health survey. the survey was used to determine physical functioning(pf), role limitations due to physical health(rp), role limitations due to emotional problems(re), vitality/energy (vt), mental health/emotional well-being (mh), social functioning (sf), bodily pain(bp) and general health(gh) [10]. a composite score for the mental component and physical component scales were calculated. results: all of the cases showed much individuality in rates and progression of assisted walking. this intervention showed no clinically meaningful trends in heart rate, however, improved muscle bulk (increased calf circumference) was found in both participants. improvement of between 8-10% was found for mental quality of life; however physical outcome scores were conflicting. indeed, the intervention showed a reduction in both physical functioning and increase in bodily pain in each case respectively. conclusion: due to the current lack of knowledge of the physical demand of these types of devices, it is imperative that clinical guidelines, for progression of standing and walking time, are implemented. habib noorbhai affiliation: cape peninsula university of technology additional authors: habib noorbhai, timothy noakes a qualitative evaluation of backlift batting techniques taught by cricket coaches introduction: the art and science of cricket has continuously evolved in the last century. the straight backlift was institutionalised first in 1912 followed by the marylebone cricket club's coaching manual in 1954. until 2007, it was common knowledge to coach the straight backlift to non-elite cricketers. presently, it is common practice for coaches to not consider the straight backlift as the only dogma. our previous studies have shown that both successful elite batsmen and non-coached cricketers employ a lateral backlift and are able to score runs easily. therefore, the aim of this study was to evaluate the teachings of the backlift batting techniques among multi-levelled cricket coaches. methodology: multi-levelled cricket coaches (n = 120) from seven international cricket council (icc) countries (south africa, australia, new zealand, england, india, pakistan and west indies) were evaluated utilizing an online survey questionnaire through google forms. a mixture of 13 open and closed-ended questions were purposively asked to gauge instinctual insights of their coaching methods and perceptions. these questions were related to their demographics, insights of backlift batting techniques and implications of batting techniques. both descriptive and inferential statistics were utilised to analyse categorical feedback with statistica 11. the level of significance was set at p<0.05. results: a majority of cricket coaches (70%) were not aware of what a looped or lateral backlift constituted of (p<0.05). in addition, more than 70% of cricket coaches utilized either the straight backlift or the backlift in the directions of the slips in their coaching methods (p<0.05). a distinctive finding was the variance of feedback received by all the cricket coaches. based on this evaluation, it was found that cricket coaches are coaching the backlift differently. some of the proposing quotes from the cricket coaches included: “one needs to teach the basics of batting to young cricketers by hitting the ball and treating each player as an individual”. in contrast, opposing quotes from the cricket coaches included: “one needs to apply a generic approach when coaching batting technique to cricket players and it doesn't matter whether the face of the bat is open or closed”. conclusion and coaching implications: this study has shown a distinct variance of coaching backlift batting techniques by 70% of multi-levelled cricket coaches. this is a slight concern, especially at grass-root level, as previous studies have shown that a straight backlift batting technique can limit the potential of a naturally gifted batsman. the way forward is to congregate all cricket coaches from the icc coaching associations in order to educate and demonstrate why and how the lateral backlift batting technique is a strong determinant for a batsman's success, at all levels. keywords: cricket, backlift batting techniques, cricket coaching, qualitative evaluation 54 habib noorbhai affiliation: cape peninsula university of technology additional authors: habib noorbhai, prof leon van niekerk a scientific and psychological analysis of the proteas performances during the last seven cricket world cups the south african cricket team comprise of some of the most highly ranked players, yet despite this, one could say that they have had an unfavourable streak at the past seven cricket world cups having not reached a world cup final. this paper aims to critique the assumptions behind the proteas' performances during several world cup campaigns and to show that the lay press original label of 'chokers' for the past two decades is not an accurate description. terms such as 'choking', the 'yips' and other psychological terminology such as stereotype threat that apply to elite sportsmen need to be differentiated as these vary. in addition, an analysis of the proteas performances over the years are performed and associated factors are discussed. it must be highlighted that we should be asking different questions instead of providing different answers to the same questions. further research should be conducted at real-time game situations among the proteas cricket team and other national teams, in order to provide an effective intervention approach. this would further enhance an understanding of the team dynamics prior to knockout tournaments such as the icc cricket world cup. s.o. onagbiye affiliation: physical activity, sport and recreation focus area, north-west university, potchefstroom additional authors: s.o. onagbiye, s.j. moss, m. cameron managing non-communicable diseases in an african community: effects, compliance, and barriers to participation in a four-week exercise intervention. introduction: to determine the compliance, barriers, and effects of participation in a four-week exercise intervention to reduce risk factors for ncds among setswana-speaking community-dwelling potchefstroom adults from a low resourced area of south africa. methods: an exercise program and associated pre-post test were performed by 76 participants (men, n= 26 and women, n= 50) aged 35 to 65 years. baseline and end tests included height, weight, hip and waist circumference, heart rate, blood pressure, glucose, cholesterol, quality of life, and cardiorespiratory fitness measurements. the intervention consisted of three days/week combined aerobic and resistance exercise at an intensity of 70% hrr as determined at baseline. compliance and barriers to participation were determined post-intervention by means of attendance registers and interviews. ancova with adjustment for pre-test was performed for all repeated variables. the cronbach's alpha coefficients for exercise benefits were 0.81 and for barriers 0.84. results: of the 26 men (40.8±5.45 years) and 50 women (43.6 ± 7.8 years) recruited, 54 completed the intervention (71% compliance). the fourweek aerobic exercise intervention significantly reduced body mass, rpe and mcs in men, and body mass, bmi, vo2max, rpe, glucose, pcs and mcs in women. participants reported that the exercise milieu as a major barrier to exercise compliance while the interviews reported lack of time. conclusion: a one month exercise intervention elucidated positive changes in risk factors for ncds in a low-resource community. a drop-out rate of 29 % in this study is consistent with other exercise intervention trials. exploration of the reported barriers may be useful for planning to increase compliance with future programs. keywords: physical activity intervention, cardiorespiratory fitness, quality of life, non-communicable diseases, adults, setswana adedayo osholowu affiliation: elite health systems (ehs) sports medicine, orthopaedic surgery and rehabilitation clinic additional authors: adedayo osholowu, onimisi sunday salami, jimisayo osinaike arthroscopic repair following a menisci tear in two nigerian footballers: a case report. introduction: reports of arthroscopic menisectomy and other minimally invasive orthopedic repairs are rare in nigeria and the rest of sub sahara africa. most athletes have to undergo open arthrotomy or continue to be managed with conservative options greatly hindering return to full performance and sometimes leading to the loss of a career and sometimes a means of livelihood for a family. a database search of medline, cinhal, and sports discus did not reveal any such cases, as most of the literature from sub saharan africa is focused on musculoskeletal trauma and infections. this report documents the 2 cases of arthroscopic menisectomy in young nigerian football players. it details the surgical repair and management and the physiotherapy rehabilitation to full function and return to play. presentation of case: this case report presents two male footballers who presented to our clinic with complaints of pain on the lateral aspect of the right knee which was sufficient to prevent him from playing. in both cases musculo-skeletal ultrasound of the knee showed a tear of the posterior horn of the medial meniscus shown as hypoechoic lines with extension to the articular surfaces. magnetic resonance imaging (mri) showed signal unequivocally reaching the surface of the meniscus further confirming the diagnosis. arthroscopic debridement and lateral partial menisectomy was applied to both knees under spinal anesthesia. in one case arthroscopy revealed a lateral collateral ligament tear which was repaired with a allograft.. discussion: while there a many cases of meniscus damage in the sports community in nigeria and the rest of sub saharan africa, arthroscopic repairs or meniscectomies have rarely been reported in literature. generally most cases are managed by conservative methods involving physiotherapy and pain management which in cases where this is not effective will result in a reduction in performance during sport and early onset arthritis. football is considered a high-risk sport for knee ligament and meniscal injuries. in the developed world a significant number of these patients undergo anterior cruciate ligament (acl) reconstruction or arthroscopic meniscal repair. in contrast, there has been little mention of the role of arthroscopy or the treatment of sports-related injuries within the scope of musculoskeletal care in nigeria and the rest of sub saharan africa. we report here our experience performing arthroscopic surgery on 2 athletes in nigerian. our goal in this report is to begin the discussion in the orthopedic community regarding when it is appropriate to introduce arthroscopy to the sports community in nigeria and how to best make it sustainable. conclusion: arthroscopic surgery can be successfully applied in the treatment of meniscal tears. the advantages of the method include good visualisation during surgery, low morbidity and early healing and return to sport. with recent advances in arthroscopic techniques and methods, the indications for arthroscopic treatment must be extended to the sports community in nigeria and the rest of sub saharan africa. 55 jessie turner pearson affiliation: department of human kinetics and ergonomics, rhodes university additional authors: jessie turner pearson, matthias goebel accommodation and job assignment for impaired or disabled workers some compensation systems do not encourage permanently restricted workers who have been disabled due to work-related injuries to return to work. however, appropriate job placement of impaired workers has been shown to result in feelings of independence, usefulness and responsibility, as well as financial security. physically impaired employees in many workplaces have experienced job discrimination because colleagues and supervisors assume that their work performance will be affected by physical limitations resulting from their disability. this theoretical paper discusses the possibilities of assigning workers to appropriate jobs based on their specific capabilities and limitations. the option of providing certain job accommodations in the form of workplace restructuring is also discussed. an ergonomics approach to designing industrial workstations attempts to achieve a balance between worker capabilities and task requirements to optimize worker productivity, as well as provide physical and mental wellbeing, job satisfaction and safety. for impaired workers, additional considerations need to be given to their functional limitations and altered physical capabilities. in some cases, modifications or alterations may need to be made to existing workplaces to accommodate these capabilities. this paper investigates the possibility of evaluating specific worker limitations and capabilities through a thorough functional analysis, and matching these to task demands determined through a thorough job analysis at the workplace, to achieve the best possible productivity and worker well-being. lervasen pillay affiliation: university of witwatersrand, cessm additional authors: lervasen pillay, prof demitri constantinou, prof yoga coopoo, arthritic patients' views and perceptions on exercise as an adjunct treatment regime for managing their condition. objectives: this study aimed to assess the views of arthritic patients towards exercise as an adjunct treatment modality in managing their condition, the incidence of different healthcare providers in prescribing exercise, the exercise types and frequencies and the outcome of the effects of exercise on pain and activities of daily living activity. methods: a cross sectional survey study design was used. patients of private general practitioners and a biokineticists' based in the southern suburbs of johannesburg were invited to participate in the survey to assist with the collection of data. questions were developed to determine various aspects of the effect of exercise and patient attitudes toward exercise as an additional management tool in patients with arthritic disease falling within the inclusion criteria. secondary to this, information on the type of healthcare providers prescribing exercise, exercise types and outcomes of exercise were also collected. outcomes were measured based on the patient's subjective responses based on improvements of the participants' arthritic conditions symptoms and activities of daily living with exercise. results: a total of 67 patients were surveyed. males counted for 25.4%, females 73.1%. age distribution was as follows: 59.7 %( n=40)>50 years of age, 35.8% (n=24) 30-50 years of age and the remaining 4.5% (n=3) <30 years of age. most respondents suffered from osteoarthritis (n=29), followed by rheumatoid arthritis (n=27), gout (n=5) and post traumatic arthritis (n=3) while the remainder were not specific. exercise was prescribed by doctors (but not specific enough), followed by physiotherapists then biokineticists. exercise alone improved pain and activities of daily living by 11.1%, while medication improved 21.1% while vast improvement was noted in the combination of exercise and medication (32.5%). conclusion: observations and analysis from the study concludes that there is benefit of exercise in treating arthritic disease best in combination with medical treatment. patients believe that exercise assists them in managing symptoms of arthritis. therefore it is an important adjunct treatment modality. doctors were in fact advising exercise more than other healthcare providers but this advice was very non-specific. limitation of this study was the small number of participants. future research should be directed toward exploring the reasons why healthcare practitioners are not specific in their exercise advice. this study is consistent with other studies in this field of study. keywords: management of arthritic disease, exercise prescription, exercise as an adjunct treatment modality, exercise and pain relief, exercise and arthritis lee pote affiliation: rhodes university additional authors: lee pote, candice christie strength and conditioning practices of university and high school level cricket players: a south african context introduction: cricket is one of the world's major team sports, however it has received very little research attention, particularly with regards to the physical demands of the game. furthermore, no studies have critically examined the strength and conditioning practices of cricket players. therefore, the purpose of this study was to examine the strength and conditioning practices of school boy and university level cricket players in south africa. this is important so that current practices that are being implemented can be adapted or changed accordingly to reduce the risk of injury and improve player performance. methods: the participants recruited for this study were the head strength and conditioning coaches or coaches (in the case of no strength and conditioning specialist), at 12 university and 50 high school teams. the university teams selected were based on their participation in the varsity cup cricket and university sport of south africa (ussa) competitions. the high school teams chosen were the top 50 in the country at the time (rankings as of 9th march 2015). participants were required to complete an online survey that was based on previous questionnaires for strength and conditioning research as well as cricket specific and injury statistics questions. the survey itself consisted of three main sections: general questions which included background information on the coaches as well as their degrees, diplomas and qualifications. this section also focused on general conditioning practices such as physical testing, flexibility, speed and agility development as well as plyometric and resistance training. cricket specific questions focusing on conditioning practices and player workload monitoring for batsmen, bowlers, fielders and wicket keepers. injury and injury prevention questions, including injury monitoring, prevention exercises and common injury sites for batsmen, bowlers, fielders and wicket keepers results: data are still being collated 56 france rossouw affiliation: dept physiology, division biokinetics & sport science, university of pretoria additional authors: france rossouw, gary miller, j schuker prevalence of dietary supplement intake and influencing factors among gymnasium attendees in pretoria introduction: studies report high prevalence of dietary supplement intake amongst gymnasium attendees worldwide. to date, no research has been conducted on this issue in a south african city. objectives: to determine the prevalence of dietary supplement intake in individuals who exercise regularly in gymnasiums in the city of pretoria, south africa, and discuss the influencing factors. furthermore, to compare results with those obtained in a study conducted in belo horisonte, brazil, utilising the same questionnaire. methods: the questionnaire was obtained and translated from portuguese into english. individuals (n = 269, aged 31.5 ± 10.7 y; men = 150; women = 119) frequenting 17 gymnasiums throughout pretoria were recruited. after obtaining informed consent, participants completed the questionnaire. descriptive statistics and chi-square tests were performed. results: exercise participation comprised mostly aerobic (76.6%) followed by anaerobic exercise (62.1%). reasons for exercising included healthy habit (70.6%), to lose weight (42.8%) and to gain muscle mass (51.3%). dietary supplement use was high (71.4%). the highest intake was in men (60.9%). the two products with the highest consumption rate were vitamins and minerals (43.1%) and supplements rich in protein (35.3%). women ingested more meal replacement shakes and natural herbal products than men. the majority of men took supplements in order to gain muscle mass and improve performance, whereas the majority of women took supplements for weight loss / fat burning, to replace meals and prevent future illness. more than half (51.6%) of the participants used dietary supplements through their own initiative. very few of them consulted a doctor (4.2%) or dietician (5.2%). the intake of dietary supplements was more common in participants < 30 years (54.2%). conclusion: the study shows a high prevalence of dietary supplement intake amongst individuals frequenting gymnasiums in pretoria. the majority of the dietary supplement intake is self-regulated. results are comparable to the brazil study. marlene schoeman affiliation: university of the free state additional authors: marlene schoeman, rudi de wet, louis holtzhausen clinical, haematological and biochemical characteristics of south african gold-miners presenting with exercise-associated muscle cramps, part 1: background and methodology introduction: consensus on the pathogenesis of exercise associated muscle cramps (eamc) has not been reached. two main schools of thought exist, either proposing that (1) dehydration and electrolyte depletion or (2) altered neuromuscular control with muscle fatigue cause eamc. several factors within these hypotheses are conflicting and unexplained, possibly because of a lack of good data, making it difficult to inform evidenced based practices for the prevention of eamc. underground miners are especially prone to muscle cramps, yet no data were available to gain insight into the pathogenesis of eamc in this population group. the aims of this study were to describe environmental, biochemical and haematological variables in gold miners with eamc and compare it with a control group of miners without eamc. the study consisted of two parts (retrospective and prospective) which required detailed methodological considerations and yielded extensive results and conclusions. therefore, this study will be presented in two parts. part 1 will focus on the background and methodology, while part 2 will focus on the results and conclusions. methodology: the retrospective descriptive study involved underground mine workers who presented with eamc over 18 months in a sa gold mine (cra group). the prospective study consisted of a collection of biological data and blood profiles before (conpre) and after (conpost) 8 hour shifts on a volunteer group of underground mine workers not presenting with eamc to generate normative data for underground mine workers and comparative data for the cra group. participants were classified into four groups based on the functional nature of the specific job descriptions comprising physical stresses such as vibration, cramped body positions for prolonged periods, high physical exertion and distance walking. despite the large number of cra participants, data were generally non-parametric. results: results and discussions are categorised under hydration, electrolyte disturbances, muscle damage and inflammation to align with aspects from the two schools of thought regarding eamc. marlene schoeman affiliation: sport and exercise medicine, university of the free state additional authors: marlene schoeman, ceri diss, siobhan strike unilateral jump mechanics in transtibial amputees introduction: jumping is a fundamental skill in recreational sport and offers great potential for stimulating osteogenesis in osteoporosis prone amputees. while a reasonable body of research on amputee walking and running gait has accumulated to identify typical compensations and adaptations for amputees, a dearth of literature on amputee jumping exists. jumping is mechanically different and more demanding than walking and running with a greater vertical force component. the aim of this study was to address the lack of knowledge on amputee jumping by exploring the underlying mechanics of performing the unilateral countermovement jump. methods: six recreationally active unilateral transtibial amputees (ttas) took part. amputees were included if they were at least 1 year postamputation with no secondary pathology and had an amputation of a traumatic nature. all ttas wore patellar tendon-bearing sockets with rigid pylons and their own prescribed prosthetic feet. for comparison, ten healthy able bodied (ab) persons of the same age range and activity levels participated in the study. all participants wore their own athletic footwear. participants performed ten maximal unilateral countermovement jumps with arms akimbo and approximately 30 seconds rest between each trial. the single jump with the greatest vertical position of the centre of mass was used for analysis. data were collected using two piezoelectric force platforms synchronized with a 9-camera vicon motion analysis system. a mannwhitney u test was used to test for statistically significant differences (p < 0.05) between the tta and ab participants. results: very little strain energy (-0.11±0.04j.kg-1) was stored in the prosthetic keel compared to the ab intact ankles (-0.28±0.09j.kg-1) during the countermovement to be returned as positive work during propulsion and effectively contribute to the jump. generally, ttas displayed similar knee and hip roms to the ab participants. significantly reduced (p=0.000) ankle roms were accompanied by significantly reduced (p=0.016) peak ankle “plantarflexor” moments (1.99±0.41nm.kg-1), represented by the passive recoil of the prosthetic keel. average knee extensor moments (1.35±0.61nm.kg-1) were significantly reduced (p=0.031) and the average hip extensor moments (2.48±1.04nm.kg-1) as well as positive knee (0.59±0.32j.kg-1) and hip work (0.88±0.53j.kg-1) were mostly similar to those of the ab participants. conclusions: despite being exposed to a greater vertical load compared to gait, insufficient strain energy was stored in the prostheses during the countermovement, brought about by the lack in rom and compression of the cantilevered spring of the prosthetic shank. in contrast to walking and running gait, no clear compensations were noted for the reduced prosthetic rom and peak plantarflexor moments at the knee and hip, highlighting the fact that compensations seen for ttas in gait cannot be extrapolated to jumping to inform this aspect of recreational sport, prehabilitation and rehabilitation for amputees. 57 nicola sewry affiliation: university of cape town, division of exercise science and sports medicine additional authors: nicola sewry, sharief hendricks, mike lambert, bevan matthews, brad roode the velocity of ball-carriers and tacklers during shoulder tackles the most frequently executed type of tackle in rugby is the shoulder tackle. a shoulder tackle occurs when the tackler uses either shoulder as the first point of contact with the ball carrier. the aim of this study was to compare the velocity of the ball-carrier and tackler engaged in shoulder tackles, and determine whether factors such as the number of passes from the previous phase, match period, quality of attack, match location and position of tackler had an effect on the mean and approaching velocities of the ball-carrier and tackler. the velocity of of the ball-carrier and tackler during shoulder tackles (n=12) were determined using a 2d analysis tool. the tackles were also coded according to pass number, match period, quality of defence and attack, match status, defensive shape and movement, position of tackler and ball-carrier. the ball-carrier's velocity (4.10±1.85m.s-1) when entering contact was significantly higher than the tackler's velocity (5.19±3.22 m.s–1). the ball-carrier's velocity was significantly higher when entering contact further from the set piece (p<0.001), when playing away from home (p<0.001) and when ranked in the top three (p<0.001). the findings of this study provide insight into the complexities of the tackle in rugby. takshita sookan affiliation: university of kwazulu natal additional authors: takshita sookan, andrew mckune, michael ormsbee, jose antonio, nombulelo magula, umesh lalloo, ayesha motala effect of a progressive resistance training program and whey protein intake on quality of life in human immunodeficiency virus infected individual receiving antiretroviral therapy. introduction: advances in hiv treatment in the last three decades has resulted in improved health, prolonged life and substantially reduced the risk of hiv transmission. [u1] this impact broadens to all facets of life, influencing quality of life (qol). progressive resistance training (prt) combined with effective supplementation can increase muscle mass and improve physical performance in persons with hiv infection and may enhance outcomes in these patients as well as improve qol. methods: forty hiv infected participants (40.8 ±7.7 yrs, 70.8 ±16 kgs, bmi 30.9 ±7.2 kg.m2) receiving art (≥18 months) were randomly assigned to either a whey protein/resistance training (rt) group (n=18), placebo/prt group (n=14) or control group (n=8). participants received either 20g whey or placebo (maltodextrin) pre and immediately post each rt workout. whole body rt was performed 2/week for 12 weeks. to assess qol the whoqol-hiv bref 31 was used which has six domains: physical, psychological, level of independence, social relationships, [u2] environment, and spiritual. the questionnaire was completed at baseline and then at 12 weeks. the mean score of questions within each domain was used to calculate the domain score. statistical analysis consisted of a two-way anova and sidak's multiple comparison post hoc testing. alpha was set at p ≤ 0.05. results: the physical domain showed a significant time effect (te) (p=0.02) with the placebo group increasing from baseline (17.69a.u.) to post (19.15a.u) (mean difference -1.5a.u., 95% ci -2.9 to -0.05a.u.). there were no significant changes in the supplement group. the social relationships domain exhibited a significant te (p=0.02) with the placebo group increasing significantly from 14.23a.u. to 16.54a.u post (mean difference -2.3a.u., 95% ci -3.9 to -0.7a.u.). environment domain showed a significant te (p=0.002) with both placebo (15.65a.u. to 16.46a.u.; mean difference -0.8a.u., 95% ci -1.5 to -0.09a.u.) and supplement groups (14.35a.u. to 15.03a.u.; mean difference -0.7a.u., 95% ci -1.3 to 0.04a.u.) demonstrating significant increases from baseline after 12 weeks of training. the spiritual domain indicated significant te (p=0.05) with the placebo group increasing from baseline (16.38a.u.) to post (17.92a.u) (mean difference -1.5a.u., 95% ci -2.8 to -0.3a.u.). there were no significant changes in the supplement group. there were no changes in the psychological or level of independence domains for the placebo and supplement groups. there were no significant changes in the control group for any of the six domains. conclusion: several components of qol improved in art treated hiv infected individuals that participated in the prt program. changes were predominately shown in the placebo group (domains 1, 4, 5, 6). this can be attributed to positive social and environmental effects of exercise programs. exercise training is an inexpensive and efficacious strategy for improving qol in this population with can impact other facets of their lives. sharhidd taliep affiliation: department of sport management, faculty of business and management sciences, cape peninsula additional authors: sharhidd taliep, ruan rust, njabulo mhlongo, janine gray, catherine draper, sherylle calder, christi botha the relationship between ethnicity, socio-economic status and visual skill in adolescent cricket batsmen introduction: this study aims at identifying a reason for the poor batting performance of black african players by investigating the relationship between ethnicity, socio-economic status and visual skills. methods: fifty-one adolescent male skilled cricket batsmen consisting of three different racial groups were recruited. the participants completed the 3 phases of visual skill tests. phase 1: simple visual motor skills were assessed using the beery-buktenica test. phase 2: visual skills important for ball sport performance were assessed using saccadic eye movement, visual tracking, depth perception, eye-hand reaction/eye-hand coordination tests. phase 3: visual skills important for cricket batting performance were assessed using a temporal occlusion technique to test visual perceptual and anticipatory decision making. in the temporal occlusion task, batsmen had to predict the swing and length of the delivery at various occlusion times. socio-economic status of players was recorded using a 17-point asset score. results: phase 1: black african batsmen scored significantly worse than coloured/indian and white batsmen in the beery-buktenica test. phase 2: black african batsmen performed significantly worse that coloured/indian batsmen in the saccadic eye movement, eye tracking, and eye-hand reaction/eye hand coordination test and significantly worse than white batsmen during the eye tracking test. phase 3: black african batsmen were significantly worse than white and coloured indian batsmen at predicting swing at 3 occlusion times (200ms after ball release, 300ms after ball release and at ball bounce). for the prediction of length, black african batsmen were worse than white and coloured/indian batsmen at 200ms after ball release. there were no significant differences between the coloured/indian and white batsmen for all phases of visual skills testing. there was a significant positive correlation between socio-economic status and all three phases of tests. conclusion: black african batsmen had poorer visual skills than white and coloured batsmen for all phases of visual skill tests providing a possible reason for their poor batting performance. poor visual skills is associated with low socio-economic status as these players seldom have access to sporting schools, facilities, structured training programmes and coaches, which could hinder their development as batsmen. we therefore emphasise the importance of including visual skills training to all coaches, trainers and exercise specialist working with adolescent cricket players. 58 eberhard tapera affiliation: national university of science & technology additional authors: eberhard tapera, lateef o.amusa release parameters of the basketball jump shot across shooting ability in zimbabwe male league basketball players introduction: basketball is a very popular game in zimbabwe and all over the world. shooting, a key skill in basketball, is mostly done as a jump shot (js). the low conversion rate of the js in league basketball matches suggests that zimbabwean league basketball players have problems in executing the js. this study described successful js in terms of release parameters (rps) (height, velocity, angle and spin) across levels of shooting ability (good, average and poor) and further investigated if significant differences existed in the rps across levels of js shooting ability. methods: twenty six players, purposively sampled from the bulawayo basketball association, made ten successive jss each from the free throw line, after a warm up. these shots were videotaped, using standard videography protocols. a panasonic vdr d1160 camera placed 10.7 metres away from, and perpendicular to the plane of motion of the subjects, mounted on a tripod 1.9 metres high, was used to videotape the js.the js videos were cut using anyconveter software. quintic coaching 4.02 v17 software was then used to compute rps for each of the cut videos. results: the study indicated that players' successful js for good, average and poor players were executed at release angles of 49.5±7.6°, 56.9 ±9.0°, 55.4±7.6°; at release velocities of 5.0±1.3 m/s,5.7±1.7 m/s, 5.6±1.7 m/s; from absolute release heights of 2.5±0.3m, 2.6±1.1m, 2.4±0.3m; with relative release heights of 1.4±0.1m, 1.4±0.1m, 1.4±0.2m and at release spins of 3.6 ±1.6 hz, 3.3±1.5 hz, 3.2±1.4 hz, respectively. the study also found statistically significant differences (p≤0.05) in the release angle, and vertical component of velocity across js ability. conclusion: it was concluded that coaches in the bulawayo basketball league need to design practises that develop optimal values of release angle and vertical component of release velocity when training for js. key words: basketball, jump shot, release parameters sharhidd taliep affiliation: department of sport management, faculty of business and management sciences, cape peninsula additional authors: sharhidd taliep, ruan rust, njabulo mhlongo, janine gray, catherine draper, sherylle calder, christi botha the relationship between ethnicity, socio-economic status and visual skill in adolescent cricket batsmen introduction: this study aims at identifying a reason for the poor batting performance of black african players by investigating the relationship between ethnicity, socio-economic status and visual skills. methods: fifty-one adolescent male skilled cricket batsmen consisting of three different racial groups were recruited. the participants completed the 3 phases of visual skill tests. phase 1: simple visual motor skills were assessed using the beery-buktenica test. phase 2: visual skills important for ball sport performance were assessed using saccadic eye movement, visual tracking, depth perception, eye-hand reaction/eye-hand coordination tests. phase 3: visual skills important for cricket batting performance were assessed using a temporal occlusion technique to test visual perceptual and anticipatory decision making. in the temporal occlusion task, batsmen had to predict the swing and length of the delivery at various occlusion times. socio-economic status of players was recorded using a 17-point asset score. results: phase 1: black african batsmen scored significantly worse than coloured/indian and white batsmen in the beery-buktenica test. phase 2: black african batsmen performed significantly worse that coloured/indian batsmen in the saccadic eye movement, eye tracking, and eye-hand reaction/eye hand coordination test and significantly worse than white batsmen during the eye tracking test. phase 3: black african batsmen were significantly worse than white and coloured indian batsmen at predicting swing at 3 occlusion times (200ms after ball release, 300ms after ball release and at ball bounce). for the prediction of length, black african batsmen were worse than white and coloured/indian batsmen at 200ms after ball release. there were no significant differences between the coloured/indian and white batsmen for all phases of visual skills testing. there was a significant positive correlation between socio-economic status and all three phases of tests. conclusion: black african batsmen had poorer visual skills than white and coloured batsmen for all phases of visual skill tests providing a possible reason for their poor batting performance. poor visual skills is associated with low socio-economic status as these players seldom have access to sporting schools, facilities, structured training programmes and coaches, which could hinder their development as batsmen. we therefore emphasise the importance of including visual skills training to all coaches, trainers and exercise specialist working with adolescent cricket players. eberhard tapera affiliation: national university of science & technology additional authors: eberhard tapera, lateef o.amusa release parameters of the basketball jump shot across shooting ability in zimbabwe male league basketball players introduction: basketball is a very popular game in zimbabwe and all over the world. shooting, a key skill in basketball, is mostly done as a jump shot (js). the low conversion rate of the js in league basketball matches suggests that zimbabwean league basketball players have problems in executing the js. this study described successful js in terms of release parameters (rps) (height, velocity, angle and spin) across levels of shooting ability (good, average and poor) and further investigated if significant differences existed in the rps across levels of js shooting ability. methods: twenty six players, purposively sampled from the bulawayo basketball association, made ten successive jss each from the free throw line, after a warm up. these shots were videotaped, using standard videography protocols. a panasonic vdr d1160 camera placed 10.7 metres away from, and perpendicular to the plane of motion of the subjects, mounted on a tripod 1.9 metres high, was used to videotape the js.the js videos were cut using anyconveter software. quintic coaching 4.02 v17 software was then used to compute rps for each of the cut videos. results: the study indicated that players' successful js for good, average and poor players were executed at release angles of 49.5±7.6°, 56.9 ±9.0°, 55.4±7.6°; at release velocities of 5.0±1.3 m/s,5.7±1.7 m/s, 5.6±1.7 m/s; from absolute release heights of 2.5±0.3m, 2.6±1.1m, 2.4±0.3m; with relative release heights of 1.4±0.1m, 1.4±0.1m, 1.4±0.2m and at release spins of 3.6 ±1.6 hz, 3.3±1.5 hz, 3.2±1.4 hz, respectively. the study also found statistically significant differences (p≤0.05) in the release angle, and vertical component of velocity across js ability. conclusion: it was concluded that coaches in the bulawayo basketball league need to design practises that develop optimal values of release angle and vertical component of release velocity when training for js. key words: basketball, jump shot, release parameters 59 60 jason tee affiliation: university of johannesburg additional authors: jason tee, yoga coopoo, mike lambert gps comparison of training activities and game demands of professional rugby union introduction: closely matching training session exertions with actual match play intensities ensures players are physically prepared for competition, and may prevent overtraining. methods: the movement patterns of four typical rugby union training activities (traditional aerobic, high intensity interval, game based and skills training) were compared with match play using global positioning systems (gps). the degree of difference from match play was determined by calculating cohen's effect size statistic. training activities for players in different positions were similarly assessed. movement patterns were measured as relative distance, distance walking (0-2m.s-1), jogging (2-4m.s-1), striding (4-6m.s-1) and sprinting (>6m.s-1), and sprint and acceleration (>2.75m.s-2) frequency. results: game based training is the training activity most similar to match play, but doesn't meet all match requirements for all positions. for example, there are large differences in relative distance, striding distance, sprint distance and acceleration frequency between game based training and match play for scrumhalves. conclusion: if game based training is used as the primary training activity, position specific supplementary training is required to ensure players are adequately prepared for the demands of match play. georgia torres affiliation: sasma effect of exercise intervention programs on persons with and without metabolic syndrome background: effective exercise programs for treating metabolic syndrome (mets) have not been devised. the principle aim of this study was therefore to use the anaerobic threshold (at) to design an exercise program that optimized individual exercise responses in individuals with mets. methods: ten participants with mets (metsl) exercised using a walking program which does not use the at to set training intensities. a second group of ten participants without mets exercised using velocity at at to set training intensities (non-metsv). the experimental group consisted of ten participants with mets exercising using velocity at at to set training intensities (metsv). physical, physiological and metabolic responses were measured in all groups before, during and after twenty weeks of exercise. results: bmi and waist circumference decreased whilst velocity at at increased in all training groups. the vo2 peak did not change significantly in the non-metsv group. the blood pressure response was favourable in the groups with mets yet absent in the group without mets. the metsv group was the only group to show significant, positive changes in any of the metabolic parameters (fasting insulin and homa). in addition, the training program used in the metsv group had a greater effect on reducing the number of mets components than did the training program not using at. conclusion: an exercise program using at to set intensity is effective in eliciting favourable responses in individuals diagnosed with mets while allowing a bearable exercise intensity and duration in subjects unused to the discipline of exercise training. monique tredoux affiliation: dsm/atlife (dietician) oat beta-glucan: an alternate cholesterol management nutrient for athletes the results from the sanhanes (south african national health and nutrition examination survey) data published in august 2013 typically display a cholesterol crisis. one out of four participants 15 years and older have an abnormally high serum total cholesterol (23.9%) and ldl cholesterol (28.8%), and one out of two an abnormally low hdl cholesterol level (47.9%). hypercholesterolemia is a major risk factor for cardiovascular disease. statins are the most widely used drugs to lower blood cholesterol in people with hypercholesterolemia. muscle symptoms such as pain (myalgia), myopathy and rhabdomyolysis are the most common side effects of long term statin treatment. statin-related muscle symptoms (pain, weakness and injury) may be significantly exacerbated by intense physical activity and these symptoms are further enhanced by age. an alternative treatment for athletes with hypercholesterolemia is thus warranted in many cases. bioactive oat beta-glucan has been proven to reduce blood cholesterol levels. high cholesterol is a risk factor in the development of coronary heart disease. a european food safety authority (efsa) article 14 claim exists for oat beta-glucans inferring a reduction in the risk of heart disease. this benefit is achieved with a daily intake of 3g bioactive oat beta-glucan. additionally, an efsa article 13.1 approval exists for oat beta-glucans for blood glucose control and gut health. oat beta-glucan has been shown to prolong glucose absorption which may affect energy supply in endurance exercise, may increase time to exhaustion and recovery from fatigue. oat beta-glucan should thus be considered in terms of cholesterol management, glucose control and gut health for athletes riaan van der schyff affiliation: none additional authors: riaan van der schyff, yoga coopoo an analysis of corporate on-site fitness facility models used in selected banking establishments in south africa introduction: there has been a growing interest in employee wellness programmes at south african companies, as well as in on-site fitness facilities offered as part of this employee value proposition. while there are similarities between this type of fitness facility and private or commercial facilities, the operating environment for on-site facilities is vastly different. the decision between insourcing and outsourcing the management of such a facility is very important, especially since a specific skill set and approach is necessary for this task. exercise and physical activity have been proven to be effective in increasing productivity, lowering stress levels and improving the long-term health outcomes of employees. the question is, however: what management practices are currently used for such facilities to ensure the best possible outcomes for employees who are members of the facilities? methods: the management of four on-site fitness facilities at banks in gauteng was compared based on several aspects including management of daily operations, the positioning of the service in the greater company ewp and satisfaction and the health outcomes of consumers (n=626) at the facilities. the consumers' experience of facility management was compared to managers' perspectives. findings: users of outsourced facilities were more satisfied with the state of the facilities compared to insourced facility users, although this did not influence health outcomes as no difference was found between the two groups. there was also an inverse relationship between facility fees and number of enrolled members. management approaches did not show distinct differences between the two models; rather, clear differences were shown when considering the funding models of the facilities. some funding from the company is necessary for these facilities to be viable. insourced facility managers had strategic input in employee wellness programs. conclusion: on-site fitness facilities can act as strategic levers for company employee wellness programmes and contribute to realisation of positive programme outcomes thereby impacting productivity and company bottom lines. 61 viola van der walt affiliation: physiotherapist additional authors: viola van der walt, prof yoga coopoo the role of parents regarding their support and knowledgetowards the use of nutritional supplements introduction: the use of nutritional supplements (ns) by adolescents seem to be an escalating problem in south africa. the role of parents seem to be questionable as children are allowed to use ns. despite information websites by organisations like saids and information sessions arranged by schools, parents do not seem to realize the health risks. for the purpose of this study, ns refer to any supplementary product ingested to boost the nutritional content of a normal diet to either fill a presumed need or deficiency. this could include any sportor energy drinks, tablets, powders or injections that an athlete consumes as energyor performance enhancement supplements. it includes any pharmacological or nutritional aids used in the hope of improving performance. objectives: in view of the lack of literature investigating the role of parents in the use of ns by their children in south africa and internationally, the objective of the study was to determine the attitudes and level of knowledge of parents of children on the east rand towards ns usage. methods: the design of the study was cross-sectional and used a self-administered questionnaire as well as an interview with a focus group. a sample of participants were obtained from parents of high school athletes involved in open teams in selected sport codes. participants were invited to participate voluntarily and anonymously in completing the questionnaires. the sample of participants in the focus group were obtained from coaches involved in selected open teams from the same high schools. the data was analysed using largely descriptive statistics. results: nine percent of parents indicated that they were well informed regarding ns. sixty nine percent believed that ns acted as a gateway drug and 64% indicated that they would support their children in obtaining ns without efficacy being proven. seventy five percent of parents indicated their awareness of the risk of ns being contaminated. seventy three percent of parents deem their role in the athlete-coach-parent triangle as important yet only 13% indicated that their children rely on them for knowledge regarding ns. coaches viewed the role of parents as integral in a healthy diet as they provide the means to eating habits, and indicated that the use of ns could not be ignored and needed to be acknowledged to build a good coachathlete relationship. coaches believed that more expensive ns were better products to suggest for usage yet at the same time they also admitted a lack of knowledge regarding ns. conclusion: the role of parents are deemed as very important by coaches. both parties demonstrated limited knowledge regarding ns. parents have a positive attitude towards the use of ns by their children despite indicating that there are health risks related to the usage of ns. parents considered the success of their children in sport performance as important for future development of their children. lynn van rooy affiliation: university of johannesburg additional authors: lynn van rooy, yoga coopoo the change in knowledge regarding nutrition in coronary artery bypass graft patients introduction: in order to reduce coronary artery disease (cad) risk, moderate physical activity should be combined with other lifestyle modifications, such as proper nutrition, to have a dramatic impact. this necessitates educational and preventative measures, which should begin in childhood and continue throughout life. the aim of this study was to measure the change in nutrition knowledge of coronary artery bypass graft patients by implementation of a lifestyle intervention programme. methods: the hawkes and nowak nutrition knowledge questionnaire (1998) was administered to 18 coronary artery bypass graft (cabg) patients to assess the change in nutrition knowledge. results: significant improvements were noted in the nutrition knowledge score (18.9±3.4 to 23.2±4.5; p=0.000). although all components measured exhibited improvements in knowledge, cholesterol reduction knowledge (5.3 ± 1.8 to 7.2 ± 1.8; p=0.0066), low fat food knowledge (3.8 ± 2.3 to 5.1 ± 2.7; p=0.011) and high fibre food knowledge (4.1 ± 1.4 to 4.7 ± 1.1; p=0.022) exhibited the highest and most significant improvements. conclusion: notably, these significant improvements in nutrition knowledge points toward effective education being delivered during the intervention. keywords: coronary artery disease, cabg, nutrition, cardiac rehabilitation, lifestyle modification. waeil ali mohammed yahya waeil affiliation: sport physiotherapy additional authors: waeil ali mohammed, yahya waeil, mohammed saeed alkhleefa neurological pain in football players simulating groin pain.cupping test stored the problem introduction: groin pain is a common problem found in many athletes. many athletes will present to clinicians with a history of groin pain that may be acute or chronic in nature, and may stem from a single traumatic event or repeated microtrauma to the region or it may be due to nerve roots damage spine could cause radicular symptoms referred to the pelvis or groin. sudan-cupping test is a newly applied and newly registered dry cupping test, based on the use of different sized cups for cupping over certain areas of spine. the test can detect the radiating pain to the joints (knee, ankle or shoulder) and muscles. methodology: 500 professional football players at the age between 17 and 30 years were examined for groin pain for the period 2012-2014. players are examined to detect symptoms that suggest some problem with the nerves (numbness, tingling, weakness or pain).sudan cupping test is applied to detect radiating pain from the lumber spine. positive sudan cupping test are sent for nerve conduction study to confirm the presence of nerve roots damage. results: 61 players with groin pain. 39 chronic and 22 acute cases were found to have sudan cupping and ncs positive results suggestive for nerve roots compression. they were diagnosed and treated as neurological groin pain injuries. conclusion: diagnosis is the key for the treatment and rehabilitation of groin pain. sudan cupping resistant cases for treatment.it helps the players to return fast to the field test is helpful for the detection of the origin of the groin pain. this decreases the number of. 62 karen welman affiliation: stellenbosch university additional authors: karen welman, tania gregory non-supportive touch improves postural sway in active and inactive individuals with parkinson's disease objective: to determine if activity status influences static postural stability (ps) with and without non-supportive light manual touch (lmt) in mild to moderate parkinson's disease (pd). background: pd individuals demonstrates balance impairment and a high incidence of fall-related injuries, which is associated with inactivity and reduced quality of life. inactivity still remains one of the greatest problems in pd, although exercise has shown to be beneficial in improving functional abilities and reduce fall risk. therefore it is vital to investigate cost effective non-pharmacological interventions to improve balance. moreover it is believed that pd individuals have diminished proprioception due to impaired sensory integration and increased reliance on visual feedback for balance. however, recently researchers reported that touch, which is independent of mechanical support, may improve static ps via tactile feedback. methods: relative smoothness (jerk), amplitude (rms), mean velocity (mv) with a tri-axial accelerometer and perceived stability were assessed during a static balance task under 6 sensory conditions. participants completed a modified-tandem standing task under eyes open (eo), eyes closed (ec), unrestricted manual contact (umc), lmt only and no manual contact (nmc) as well as on (+f) or off a foam pad conditions. results: mean age for 9 active (act) and 7 inactive participants were 67 (sd 8) and 70 (sd 4) years, respectively. regardless of the sensory condition act tend to have less jerk and rms (p=0.06).groups presented less ps during all lmt conditions compared to nmc (p<0.01) and umc (p<0.01). ec lmt+f differed between the groups for jerk (p<0.001) and rms (p=0.03), with act showing 154% and 40% less jerk and rms, respectively. medial lateral mv was 44% slower in the act during ec nmc (p=0.04) compared to inactive. groups felt more successful when they received lmt compared to nmc (p<0.01) . conclusions: non-supportive lmt may be more effective in reducing ps than umc in both active and inactive pd individuals. suggesting that nonsupportive lmt can be used to improve static balance in individuals with mild to moderate pd. in addition, active individuals demonstrated less static postural instability compared to inactive individuals. tactile feedback activities could help individuals to maintain ps enabling them to perform daily activities safely with a decreased fall risk. sajsm 471.indd original research sajsm vol. 25 no. 3 2013 77 background. exposure to competitive football is increasing among male youth football players in nigeria. however, medical support to abate the impact of injuries appears inadequate and there is limited literature to show whether youth football players are knowledgeable about, and practise effective measures for injury prevention in football (ipf). objective. to assess the knowledge and behaviour of male youth football players regarding ipf and the availability of medical care for players. methods. we conducted a cross-sectional study among all registered first-division players of a male youth football league in lagos, nigeria. using a self-administered questionnaire, we assessed players’ knowledge regarding ipf, awareness of the fédération internationale de football association (fifa) 11+ injury-prevention programme, injury-prevention behaviour and availability of medical attendants during training and competitive matches. results. the mean age of the players was 18.5 years (standard deviation (sd) ±1.7; range 12 19). their overall mean knowledge score regarding ipf was 4.40 (sd ±1.92) from a total score of 9, with the majority falling into the poor (39.1%) and fair (43.9%) knowledge categories. most (79.3%) players were not aware of the fifa 11+ programme. less than half (40.5%) wore shin guards during training sessions, while 52.5% reported wearing shin guards during matches. less than two-thirds always warmed up or cooled down at training or matches. about three-quarters (73.1%) and over half (52.1%) reported not having medical attendants working with their teams during matches and training, respectively. conclusion. there is a clear deficiency in the knowledge and behaviour of injury-prevention measures among nigerian male youth football players, and adequate medical care is lacking. there is a need for injury-prevention advocacy and implementation of effective interventions to bridge the identified deficiencies in youth football in nigeria. s afr j sm 2013;25(3):77-80. doi:10.7196/sajsm.471 injury prevention in football: knowledge and behaviour of players and availability of medical care in a nigerian youth football league o b a owoeye,1 bpt, msc; s r a akinbo,1 bsc, msc, phd; o a olawale,1 bsc, msc, phd; b a tella,1 bsc, msc, phd; n m ibeabuchi,2 mbbs, msc, phd 1 department of physiotherapy, faculty of clinical sciences, college of medicine, university of lagos, nigeria 2 department of anatomy, faculty of basic medical sciences, college of medicine, university of lagos, nigeria corresponding author: o b a owoeye (obowoeye@unilag.edu.ng) football (soccer) players are known to suffer relatively high rates of injury compared with participants in other sports,[1,2] and youth football players are no exception to this.[3] young people are particularly at risk of sports injury because of high levels of exposure at a time of major physiological change.[4] the importance of injury prevention in football (ipf) among young players cannot be overemphasised as talented players need to stay injury-free as far as possible, to get to the peak of their careers. implementation of injury-prevention measures in this extremely vulnerable population of disadvantaged youth is therefore imperative. a set of programmes such as core stability, proprioception and strength training, dynamic stretching, protective and suitable equipment, appropriate surface as well as appropriate training, adequate recovery, psychology and nutrition have been described as main components of injury prevention and rehabilitation in football. [2,4-8] football players in nigeria are faced with huge challenges. a major problem is the low level of financial resources for professional, amateur and youth clubs, most of which are not well funded, especially those owned by the government.[9] appropriate facilities, personnel and equipment are usually lacking and this is even worse at the youth football level. consequently, players are faced with factors that predispose them to injuries that militate against their football career. it has being emphasised that the prevention of injuries should always be a priority and is even more important when treatment possibilities are restricted, as in many parts of africa.[10] to enable the implementation of prevention programmes, knowledge of preventive measures among sports participants is imperative. regulatory bodies and team owners are obliged to provide adequate information and training on injury-prevention strategies to their players.[11] in view of this, the federation of international football associations (fifa) through the fifa medical assessment and research centre (f-marc) has developed a neuromuscular injury-prevention programme, referred to as fifa 11+, to help reduce the incidence of injuries in football.[12] fifa 11+ is a complete warm-up programme developed by f-marc and experts in the field of ipf to reduce injuries among male and female football players aged ≥14 years.[13] however, the 78 sajsm vol. 25 no. 3 2013 level of awareness and implementation of the fifa 11+ among footballers, coaches and sports medicine personnel in nigeria is not known. furthermore, there is generally limited evidence to show whether or not youth football players are knowledgeable about effective measures for ipf and whether they actually practise such. to date, no study has investigated the knowledge and behaviour relating to ipf in male youth football. the aim of this study was therefore to assess the knowledge and behaviour of male youth football players regarding ipf and the availability of medical care for players. methods a cross-sectional cohort study was conducted on all registered first-division team players of a male youth football league in lagos, nigeria (lagos junior league). all first-division players of the 14 teams (a total of 260 players) registered for the 2011/2012 league season were invited to participate in the study. a self-administered questionnaire, adapted from previous studies[11,14] and modified to address the specific objectives of the study, was used for data collection. the questionnaire was pilot-tested among 16 players of a second-division team of the lagos junior league. players were asked to report any ambiguities in questions or the format of the questionnaire. minor revisions were made on the basis of feedback from the pilot study. for the purpose of comprehension among players, ‘water consumption’ was used as a synonym for fluid replacement or rehydration in the questionnaire. the questionnaire comprised three sections: section a assessed players’ demographics; section b assessed players’ knowledge regarding ipf and awareness of the fifa 11+ injury-prevention programme; and section c assessed players’ injuryprevention behaviour and the availability of medical personnel for competitive matches and training sessions. the questionnaire was distributed to all players towards the end of the 2011/2012 league season. the study was carried out between february and march, 2012. the various teams were visited consecutively. questionnaires were self-administered on training grounds after the delivery of brief information on the objectives of the study and instructions on how to complete the questionnaire. a questionnaire was considered to be invalid for data entry if: (i) less than 50% of the returned questionnaire was completed (based on the total number of questions); or (ii) the questionnaire was returned to the researcher or research assistant later than the time of administration. yes (%) no (%) 0 10 20 30 40 50 60 70 80 90 100 97.3 2.7 7.4 92.6 52.0 48.0 51.1 48.9 30.2 69.8 leg injuries can be prevented by wearing shin guards fair play is important to prevent injuries strong muscles are necessary to prevent injuries injuries are more likely to occur towards the end of a match taking water adequately during play can help reduce injuries fig. 1. players’ knowledge on injury prevention in football. always (%) often(%) sometimes (%) never (%) wearing shin guards: during training during matches taking carbohydrates: before trainings/matches after trainings/matches warm-up: before training before matches cool-down: after training after matches core stability and strength training: personally as a team 40.5 9.7 33 16.4 52.5 12.5 22.5 11.7 25.6 22.7 39.8 11.9 34.7 28.9 29.5 6.9 60.6 17.6 18.1 3.7 64.2 11.4 21.6 2.8 5.917.851.4 56.6 17.1 24.9 22.4 4.1 42 26.5 28.2 3.3 45 24.9 21.9 8.3 fig. 2. injury-prevention behaviour of players. no yes, sometimes yes, most of the time yes, all the time 52.1% 73.1% 28.8% 12.8% 8.2% 6.4% 11.1% 7.7% during matches during training sessions fig. 3. availability of medical attendants during matches and training sessions. sajsm vol. 25 no. 3 2013 79 data were summarised using frequencies, percentages and means (± standard deviations (sds)) and cross-tabulation chi-square analyses were done as required. a 9-point knowledge scale for the assessment of players’ knowledge regarding ipf was generated from the questionnaire. based on the knowledge score range, players’ overall knowledge was categorised as poor (0 3 points), fair (4 6) or good (7 9). statistical significance was set at p<0.05. ethical approval of the study was obtained prior to its commencement. approval to conduct the study was also obtained from the league administrators for official access to the various football teams included in the research. results player demographics and ipf knowledge a total of 212 of the 260 questionnaires distributed were returned (81.5% response rate); however, only 182 were valid for data analysis. the players’ mean body mass index (bmi) was 21.95 kg/m2 (sd ±4.39) and mean age was 18.5 years (sd ±1.7; range 12 19) with 9.75 years (sd ±3.71) of football experience. in terms of player position, 14% were goalkeepers, while 31.2%, 30.6% and 24.2% were defenders, midfielders and strikers, respectively. based on the 9-point ipf knowledge scale, the overall mean knowledge score was 4.40 (sd ±1.92). based on the knowledge score range, most players fell within the poor (score 0 3) and fair (score 4 6) knowledge categories (39.1% and 43.9%, respectively). fig. 1 presents specific questions regarding players’ knowledge of ipf. the majority of the players correctly identified that wearing shin guards and fair play behaviour were important for ipf (97.3% and 92.6%, respectively). however, a large proportion of the players (69.8%) wrongly indicated that adequate consumption of water (rehydration) was not important for ipf and nearly half (48.0%) also wrongly indicated that strong muscles were not important for ipf. over two-thirds (69.7%) of players claimed to be knowledgeable about ipf. however, 90.6% wished to know more about ipf. the majority (79.3%) of the players had never heard about the fifa 11+ warm-up programme before the time of the study. football experience, playing position and ipf knowledge table 1 shows the relationship between players’ years of football experience, playing position and knowledge of ipf. the players’ mean knowledge score decreased slightly with increasing years of football experience. however, no statistically significant relationship was found between years of football experience and players’ knowledge of ipf (p=0.737). also, no significant relationship was found between players’ positions and knowledge scores (p=0.732). injury-prevention behaviour of players fig. 2 shows the injury-prevention behaviour of players. less than half (40.5%) of the players reported always using shin guards during training sessions and only 52.5% reported always wearing shin guards during matches. about one-sixth (16.4%) and 11.7% of players never used shin guards during training and matches, respectively. a few of the players consciously consumed food or snacks rich in carbohydrates before (25.6%) and after (34.7%) play. less than twothirds of players always warmed up or cooled down at training or matches. availability of medical attendants about three-quarters (73.1%) and over half (52.1%) of the players did not have medical attendants working with their teams during training sessions and matches, respectively (fig. 3). for the few players that seldom, often or always had medical attendants, the masseur (55.8%) and the physiotherapist (36.0%) were mostly reported as available (table 2). discussion risk communication has been argued to be the most essential element of a risk-management process, because without effective communication strategies, risk mitigation will not be accessible to stakeholders. [8] this study found that only a few players in the study population had a good knowledge of ipf and the overall mean knowledge score was below average. furthermore, the majority of the players had never heard about the fifa 11+ injury-prevention programme and its implementation among football players. this implies that the majority of these players were not well exposed to current information relating to ipf. however, almost all players wished to know more about ipf. proprioception, core muscle strength and stability training have been established in the literature as components of ipf.[5,6,13] a neuromuscular training programme such as the fifa 11+ is one football-specific injury-prevention programme proven to be effective in improving physical performance and reducing injury risk among young female players [13,15] however, implementation of this programme appears to be limited by the low level of awareness among players and coaches in table 2. self-reported medical attendants persent during matches and training sessions medical attendant* % masseur physiotherapist nurse physician pharmacist dentist 55.8 36.0 32.6 29.1 11.6 10.5 *multiple options were allowed. table 1. relationship between players’ knowledge, football experience and playing position variable n knowledge score mean (±sd) f-value p-value football experience <5 years 6 10 years >10 years 31 78 73 4.61 (±1.82) 4.46 (±2.08) 4.30 (±1.84) 0.31 0.737 playing position goalkeeper defender midfielder striker 25 56 54 44 4.84 (±1.68) 4.41 (±1.88) 4.33 (±2.15) 4.47 (±1.80) 0.43 0.732 80 sajsm vol. 25 no. 3 2013 the region. the present study reveals that the majority of the players were not aware of the fifa 11+ programme. although the programme is yet to be tested in young male players,[15] its implementation, based on present evidence, may help to abate the risk of injury in male youth football considering its potential in improving neuromuscular fitness. the sequelae of dehydration (mostly distorted body homeostasis, fatigue and impaired physical performance) predispose players to an increased risk of injury and illness in football. [8,16-17] adequate hydration during matches and training sessions has been advised as an important measure to minimise injury risk, particularly heat cramps and heat illnesses in football, and particularly in hot environments. [7,8,17] also, fair play has been documented as an established measure for ipf. [8] although most of the players knew that fair play was necessary to minimise the occurrence of injuries in football, about half of the players did not know that strong muscles and rehydration were important components of ipf. furthermore, about half of them did not know that the chances of sustaining an injury increases towards the end of a competitive match.[1] the aforementioned form some of the evidence-based information that football players are expected to have in order to avert injuries. no significant relationship was found between players’ football experience, positions and knowledge score concerning ipf. this suggests that the number of years of experience and position of play do not determine how much the young football player knows about injury-prevention strategies in football. the use of shin guards during football matches and training sessions is essential for lower-leg injury prevention, especially contact injuries to the shin.[5] also, consumption of carbohydrate-rich food or drinks prior to participation in matches and training sessions has been documented as necessary, and advocated for ipf.[7] however, there were major deficiencies in the injury-prevention behaviour of players. the main deficiencies identified related to the use of shin guards during training and matches, carbohydrate intake before and after training and matches, and cool downs before and after training and matches, respectively. as part of injury prevention, adequate injury management and rehabilitation are essential; especially in the prevention of re-injury. unfortunately, youth football is often disadvantaged with inadequate or unavailable sports medicine personnel and treatment, particularly in developing countries. this study empirically confirmed that there is limited medical coverage during training and matches in a cohort of male youth football players in nigeria. this may be attributed to a lack of funds for youth football at the developmental level. the youth football teams that participated in the study are run by local government councils in lagos state, nigeria, and a regular complaint from the coaches is the lack of, or sparse fund allocation to run teams properly. hence, most teams cannot afford the services of qualified medical personnel. this may explain, in part, why most teams that had medical attendants attached to them mainly had masseurs. it is, however, possible that some of the players mistook masseurs and traditional bone setters as qualified health personnel; players often refer to medical attendants whether qualified or not as physiotherapists, nurses or doctors. thus, the aforementioned qualified personnel might have been over-reported and unqualified personnel under-reported by the players in our study. since it is unlikely that qualified medical personnel will be available at the youth football level due to cost and other militating factors, it is important that masseurs and other unqualified attendants who are the main providers of medical services to youth football players, are trained in sports first aid to ensure proper injury management and to prevent re-injuries. the findings from this study raise the question of whether the latest injury-prevention measures are best disseminated to youth football players. scientific evidence to show that an injury-prevention strategy works does not guarantee that it will actually prevent injuries in a realworld context if it is not adopted by players and their coaches.[19] injuryprevention advocacy among players and coaches is imperative for the implementation of effective strategies in youth football. there is a need for future studies to assess barriers to implementation of such strategies for injury prevention in youth football, and this will help to direct plans for implementation. conclusion in nigerian male youth football, there is a clear deficiency in the knowledge and behaviour of players regarding injury-prevention measures; medical care is limited and non-qualified personnel predominantly attend to injured players. injury-prevention advocacy and effective interventions are needed to bridge identified deficiencies. references 1. hawkins rd, fuller cw. a prospective epidemiological study of injuries in four english professional football clubs. br j sports med 1999;33:196-203. 2. kirkendal dt, junge a, dvorak j. prevention of football injuries. asian j sports med 2010;1(2):81-92. 3. emery c. risk factors for injury in child and adolescent sport: a systematic review of the literature. clin j sport med 2005;13:256-268. 4. abernethy l, bleakley c. strategies to prevent injury in adolescent sport: a systematic review. br j sports med 2007;41:627-638. [http://dx.doi.org/10.1136/bjsm.2007.035691] 5. olsen l, scanlan a, mackay m, et al. strategies for prevention of soccer related injuries: a systematic review. br j sports med 2004;38:89-94. [http://dx.doi.org/ 10.1136/ bjsm.2002.003079] 6. mandelbaum br, silvers hj, watanabe ds, et al. effectiveness of a neuromuscular and proprioceptive training program in preventing anterior cruciate ligament injuries in female athletes: 2-year follow-up. am j sports med 2005;33:1003-1010. 7. consensus statement: nutrition for football: fifa/f-marc consensus conference. j sports sci 2006;24(7):663-664. 8. fuller cw, junge a, dvorak j. risk management: fifa’s approach for protecting the health of football players. br j sports med 2012;46:11-17. [http://dx.doi.org/10.1136/ bjsports-2011-090634] 9. agiri a. taiwo ogunjobi offers info on how to revive nigeria sports. http://www. allnigeriasoccer.com/read_news.php?nid=7149 (accessed 12 march 2013). 10. constantinou d. football injuries – surveillance, incidence and prevention. continuing medical education 2010;28(5):220. 11. hawkins rd, fuller cw. a preliminary assessment of professional footballers’ awareness of injury prevention strategies. br j sports med 1998;32:140-143. 12. f-marc. fifa 11+ a complete warmup programme. http://f-marc.com (accessed 22 may 2013). 13. soligard t, myklebust g, steffen k, et al. comprehensive warm-up programme to prevent injuries in female youth football – a cluster randomised controlled trial. bmj 2008;337:a2469. [http://dx.doi.org/10.1136/bmj.a2469] 14. twizere j. epidemiology of soccer injuries in rwanda: a need for physiotherapy intervention. msc thesis. cape town: university of the western cape, 2004. http://etd.uwc.ac.za/usrfiles/ modules/etd/docs/etd_init_1053_1175152032.pdf (accessed 9 july 2013). 15. steffen k, emery ca, romiti m, et al. high adherence to a neuromuscular injury prevention programme (fifa 11+) improves functional balance and reduces injury risk in canadian youth female football players: a cluster randomised trial. br j sports med (in press). [http:// dx.doi.org/10.1136/bjsports-2012-091886] 16. grantham j, cheung ss, connes p, et al. position statement. current knowledge on playing football in hot environments. scand j med sci sports 2010;20:161-167. 17. maughan rj, shirreffs sm, ozgünen kt, et al. living, training and playing in the heat: challenges to the football player and strategies for coping with environmental extremes. scand j med sci sports 2010;20:117-124. 18. verhagen e, finch cf. setting our minds to implementation. br j sports med 2011;45:10151016. [http://dx.doi.org/10.1136/bjsports-2011-090485] original research 80 sajsm vol 23 no. 3 2011 introduction osteoarthritis (oa) of the knee is a common cause of pain, stiffness and physical impairment in adults. the lifetime risk of developing symptomatic knee oa is nearly 45%. 1 in the usa radiographic knee oa is estimated to be present in 37% of people over 60 years of age, with symptomatic knee oa affecting 12% of that age group. 2 while the number of knee arthroplasties is expected to rise dramatically in the coming years, 3-5 many patients continue to seek non-surgical relief. while there are no disease-modifying treatments, there is good evidence for the efficacy of various exercise interventions to improve pain and function among persons with knee oa. 6 kinesthesia, balance and agility exercise (kba) is a neuromuscular training programme designed to improve dynamic joint stability and neuromuscular control. kba challenges the vestibular, visual and somatosensory systems (with adaptations generally occurring only in the somatosensory system). 7 such programmes employ agility walking drills, e.g. tandem walking, grapevine, side-stepping and balance challenge activities. given the often poor dynamic joint stability and neuromuscular control associated with knee oa, 8-10 programmes that incorporate kba have been employed as an intervention. 11-15 while not yet researched extensively, kba appears to be a promising functional treatment for persons with knee oa. fitzgerald and colleagues 11 reported a case study of a 73-yearold female patient with dynamic knee instability from bilateral knee oa. kba training and traditional therapeutic exercise were combined twice per week for 6 weeks, resulting in the patient’s return to golf and tennis and an ability to walk and climb stairs without knee instability. in another study, the authors of an 8-week, 3 times per week clinical trial 13 concluded that the addition of kba exercises had added benefits over strength training alone on all functional outcomes measured. two studies investigated the effects of kba independent of other therapeutic exercise. in one study, sekir and gür 14 used a simple 6-week, twice per week multi-station proprioceptive exercise programme to improve postural control, functional capacity and knee pain among 22 persons with bilateral knee oa. in another 8-week, 3 times per week pilot study 15 it was found that kba alone improved the pain, stiffness and physical function of subjects with knee oa equally as well as a strength training programme. few studies have compared clinic-based with home-based delivery of rehabilitation exercise for knee oa, 16-18 and no studies are known to have compared clinic-based versus home-based kba programmes. it is not yet clear if there is a meaningful difference in outcomes between these two delivery methods. deyle et al. 18 noted almost double the improvement in self-reported symptom improvement for clinic (52%) versus home-based (26%) subjects in a 4-week exercise programme. however, both groups exceeded a clinically relevant threshold for improvement. 19 in contrast, other matthew w rogers (ms)1 nauris tamulevicius (phd)2 stuart j semple (phd)1 marius f coetsee (phd)1 beth f curry (bs)3 1 department of biokinetics & sport science, university of zululand, kwadlangezwa, kwazulu-natal, south africa 2 school of human performance and leisure sciences, barry university, miami shores, florida, usa 3 cheek-powell wellness center, morton plant mease healthcare, clearwater, florida, usa correspondence to: stuart semple (ssemple@pan.uzulu.ac.za) comparison of clinic-based versus home-based balance and agility training for the symptoms of knee osteo arthritis abstract objective. to compare clinic-based (cb) and home-based (hb) deliveries of a knee osteoarthritis (oa) exercise programme. methods. outcomes from a cb exercise study (n=6) utilising kinesthesia, balance and agility (kba) exercises were compared with those from a hb kba study (n=6). both conditions trained 30 minutes, 3 days per week for 8 weeks. cb sessions were conducted in a group led by an exercise physiologist (ep); hb participants received an initial 3 sessions of one-to-one training from an ep, written/pictorial instructions, telephone and e-mail follow-up, and in-person refresher sessions during weeks 4 and 6. the primary outcome was an oa-specific physical function survey. community activity level, self-report knee stability, 15-m get up and go walk, and stair climb and descent were also measured. results. adherence was 94% in both conditions. kba improved pf in both cb (59%; 18±12.5 pts; p=0.008) and hb (33%; 7.3±7.5 pts; p=0.03), with no difference between conditions. all outcome improvements were somewhat larger for cb, but these differences did not reach statistical significance. conclusion. we found no difference in outcomes between cb and hb exercise in this preliminary comparison. our results support that kba is an effective intervention for symptomatic knee oa that may be delivered in cb or hb settings. sajsm vol 23 no. 3 2011 81 investigators have found no differences in efficacy when comparing clinic with home-based exercise interventions for knee oa. 16,17 the current investigators are engaged in a larger home-based study of kba efficacy among persons with knee oa. a pilot study 15 had demonstrated the efficacy of kba in a clinic setting, but it was not known if similar effects would be seen in a home-based programme. thus, the purpose of this preliminary study was to compare the efficacy of a knee oa-specific kba exercise programme delivered in a clinic-based versus a home-based setting. methods participants all participants (n=12) had physician-diagnosed symptomatic knee oa, reported knee pain on most days of the prior month, met a minimum score for physical function difficulties and were free of other rheumatic disease. participants were excluded if they had been engaged in a leg exercise programme in the previous 6 months, had an injection in either knee in the previous 30 days, a hip or knee joint replacement, or an unresolved balance disorder. all participants obtained written clearance for exercise from their physicians. for the present investigation, six participants were drawn from each of two larger studies, one using clinic-based (cb) kba exercise, the other home-based (hb) kba. both groups consisted of four women and two men, and all participants had been randomly assigned to the kba condition. mean age of cb (n=6) and hb (n=6) was 63.3±12.5 and 76.5±11.6 years, respectively. body mass index (bmi) of cb and hb was 35.7±11.69 and 25.2±2.21 kg/m 2 , respectively. the cb study was approved by the baycare pasco-pinellas institutional review board (clearwater, florida, usa), and the hb study was approved by the barry university institutional review board (miami shores, florida, usa). ethical standards of each board were followed and all participants signed a written informed consent form. testing protocols the physical function (pf) sub-scale of the western ontario and mcmaster university (womac) osteoarthritis scale 20 was the primary outcome measure. womac consists of three symptom sub-scales of pain (0 20 points), stiffness (0 8 points), and pf (0 68 points) and a total score which is a summation of the sub-scales. ancillary tests included the human activity profile (hap), 21 get up & go (gug), stair climb and stair descent. hap is a self-report survey that measures community based maximal and average physical activity. gug required a participant to rise from a chair and walk a distance of 15 meters as fast as possible. the best time of three gug trials was recorded. the two stair tests timed a participant first ascending (one trial) and then descending (one trial) a staircase of 10 steps. to assess knee stability, participants responded to a question from the knee outcome survey – activities of daily living scale (kos-adls) 22 addressing this factor. paired t-tests were conducted to test for differences (p<0.05) from baseline to 8-week follow-up within each of the two conditions. unpaired t-tests were used to test for differences in outcomes (p<0.05) between conditions. exercise interventions each cb session was led by one of two exercise physiologists, trained in the study protocols by the lead investigator. the cb procedures have been previously described. 15 the lead investigator, an exercise physiologist, worked one-to-one for the first three hb sessions and provided participants with written/pictorial instructions for unsupervised sessions. the investigator followed up by telephone or e-mail, and again in person at weeks 4 and 6 for refresher sessions. both cb and hb consisted of three 30-minute sessions per week for 8 weeks (24 sessions). kba exercises are described in table i. the exercise programmes were individualised for each participant’s tolerance and abilities within the framework of the overall programme. that is, fewer steps or balance time and/or repetitions would be assigned on a given exercise for a participant who reported increased pain or demonstrated difficulty with that exercise compared with other participants, and in some cases the particular activity would be modified or eliminated. in this way, the programmes were kept both safe and challenging for each participant. in no case was it necessary to modify or eliminate more than one exercise for a given partable i. agility and balance exercises exercise description wedding march step forward and slightly to one side with right foot, bring left foot together with right foot, alternate leading foot backward wedding march as above, stepping backward high knees march walk forward while flexing hip to 90 degrees side-stepping stand with feet together, step to side with right foot, bring left foot to right; repeat for prescribed number of steps; lead with left foot and then repeat in opposite direction semi-tandem walk walk heel-to-toe with heel of leading foot landing just in front of and medial to great toe of opposite foot tandem walk advanced version of above; leading heel lands directly in front of opposite foot cross-over walk walk forward with each foot landing across midline of body modified grapevine step to side with right foot, bring left foot behind right, step to side with right, bring left in front of right; repeat for prescribed number of steps; change leading foot and repeat in opposite direction toe walking walk forward on toes heel walking walk forward on heels static balance stand on one foot for prescribed period of time dynamic balance as above, with the addition of small, rapid bouncing movements note 1: agility exercises were done at a walking pace and progressed by adding more steps or increasing the pace. one set was conducted. subjects began with ~15 steps of each exercise and progressed to a maximum of ~75 steps. note 2: static and dynamic balance training used thera-band® stability trainer pads (the hygenic corporation, 1245 home avenue, akron, ohio, usa) at 3 levels of challenge (softness). both progressed to as many as three sets of up to 30 seconds. dynamic balance was also progressed with the addition of limb movements in order to further perturb balance. 82 sajsm vol 23 no. 3 2011 ticipant. compliance with the exercise prescription was determined by exercise logs for both the cb and hb programmes. participants recorded the number of steps completed for each agility exercise and the time and repetitions of the balance exercises. results adherence was 94% for both conditions. womac results are summarised in fig. 1. womac pf improved in both cb (18±12.5 points, p=0.008) and hb (7.3±7.5 points, p=0.03) at the 8-week follow-up. ancillary results are presented in table ii. for both womac and ancillary outcomes, cb improvements were generally greater, but these differences did not reach statistical significance. discussion given the high lifetime risk and increasing incidence of symptomatic knee oa, and the important role of exercise in mitigating symptoms, it is important to find low-cost, easy-to-administer exercise interventions. while patient-directed home-based programmes should be less expensive than clinician-directed supervised programmes, there has been surprisingly little research comparing the efficacy of the two approaches. we took the opportunity to compare our participants who had completed a kba training programme in clinic-based exercise physiologist-led sessions with those who completed the same programme as individuals at home with only three supervised familiarisation and two supervised follow-up sessions. while there is some evidence for the efficacy of kba training to reduce knee oa symptoms in a clinical setting, it was unknown if similar effects would be seen in a home-based semi-supervised setting. given the low power of this study (small sample and large standard deviations), our positive within groups womac results indicate a large effect size and are encouraging in terms of efficacy. large standard deviations are not unexpected in a small group with a broad range of ages (45 80 years) and varying functional limitations (though all had the mobility to safely participate in the exercise programmes). note that conclusions cannot be stated for some ancillary functional tests due to the small numbers in some cells. this was due to some subjects, mostly in the home-based study, being unavailable for follow-up testing. these subjects did return the paper-and-pencil surveys, however. our results compliment those of chamberlain et al. 16 and reeder et al. 17 these investigators found virtually no difference in functional improvement for older persons with knee oa 16 or chronic health conditions including oa 17 when comparing exercise programmes delivered in clinic-based or home-based settings. other investigators (deyle 18 ) found a clinic-based knee oa exercise programme (supplemented with home-based exercise and manual therapy) superior to a home-based exercise programme. however, at a one-year follow-up there was no difference between the clinicand home-based subjects’ outcomes, presumably because all subjects continued home-based exercises per the authors. their clinic-based intervention was noted to be substantially more expensive than the home-based intervention. note that none of the above investigators employed a kba programme. consistent with a case study 11 and three published clinical trials, 13-15 our results indicate that 8 weeks of 3 times per week kba training appears effective for treating knee oa symptoms. in our comparison, kba appears to be effective whether delivered in a clinic-based or home-based programme. in addition, both delivery methods resulted in a high adherence rate (94%). similar to deyle et al., 18 we did note a higher percentage improvement in total womac score for cb (55%) versus hb (34%). however, we found no statistical differences in change scores between groups, and both groups’ womac changes exceeded an established minimal clinically important difference of 20%. 19 given the potential cost savings and ease of delivery of home-based exercise interventions for knee oa symptoms, this is a subject worthy of further investigation. conclusion our results indicate that kba exercise taught by an exercise physio logist is effective for improving the symptoms of persons with knee table ii. ancillary outcomes, change scores versus baseline variable † clinic-based mean (sd) % change* p n home-based mean (sd) % change* p n 15-m gug (s) -1.51 (1.45) 14 0.039 5 | -0.58 (1.41) 5 0.233 4 10-stair climb (s) -1.70 (3.14) 22 0.146 5 | -1.13 (2.73) 17 0.272 3 10-stair descent (s) -3.79 (4.89) 38 0.079 5 | -1.03 (2.25) 13 0.255 3 hap mas 3.16 (2.78) 4.5 0.019 6 | 3.80 (12.1) 17 0.261 5 hap aas 3.16 (4.87) 5 0.086 6 | 7.50 (13.2) 13 0.169 4 knee stability (0 5) †† 1.60 (1.51) 53 0.077 5 | 0.00 0 3 * rounded † no between groups differences were found (p>0.05) gug = get up & go walk; hap mas = maximum activity score: ‘highest oxygen-demanding activity that the respondent still performs’; aas = adjusted activity score: ‘a measure of usual daily activities’ (15). †† kos-adls (17) scale question: to what degree does giving way, buckling, or shifting of the knee affect your level of daily activity? 0 – the symptom prevents me from all daily activity; 1 – …affects my activity severely; 2 – …moderately; 3 – … slightly; 4 – … does not affect my activity; 5 – i do not have [the symptom]. fig. 1. womac improvements at 8 weeks expressed in % change. sajsm vol 23 no. 3 2011 83 oa whether delivered in a supervised clinic-based or a semi-supervised home-based programme. future research studies with greater statistical power are needed to confirm or refute our efficacy and equivalency findings. support this research was supported by a product grant from the theraband® academy, which provided the stability trainers. references 1. murphy l, schwartz ta, helmick cg, et al. lifetime risk of symptomatic knee osteoarthritis. arthritis rheum 2008;59:1207-1213 (doi: 10.1002/ art.24021). 2. dillon cf, rasch ek, gu q, hirsh r. prevalence of knee osteoarthritis in the united states: arthritis data from the third national health and nutrition examination survey 1991-94. j rheumatol 2006;33:2271-2279. 3. australian institute of health and welfare. a snapshot of arthritis in australia 2010. arthritis series no.13, cat. no. phe126. canberra: aihw; 2010. 4. kurtz s, ong k, lau e, mowat f, halpern m. projections of primary and revision hip and knee arthroplasty in the united states from 2005 to 2030. j bone joint surg am 2007;89(4):780-785. 5. robertsson o, dunbar mj, knutson k, lidgren l. past incidence and future demand for knee arthroplasty in sweden: a report from the swedish knee arthroplasty register regarding the effect of past and future population changes on the number of arthroplasties performed. acta orthop scand 2000;71(4):376-80. 6. zhang w, nuki g, moskowitz rw, et al. oarsi recommendations for the management of hip and knee osteoarthritis: part iii: changes in evidence following systematic cumulative update of research published through january 2009. osteoarthritis cartilage 2010;18:476-499. 7. taylor jb. lower extremity perturbation training. strength cond j 2011;33 (2):76-83. 8. hubley-kozey c, deluzio k, dunbar m. muscle co-activation patterns during walking in those with severe knee osteoarthritis. clin biomech 2008;23;71-80. 9. lewek md, rudolph ks, snyder-mackler l. control of frontal plane knee laxity during gait in patients with medial compartment knee osteoarthritis. osteoarthritis and cartilage 2004;12:745-751 (doi:10.1016/j. joca.2004.05.005). 10. rudolph ks, schmitt lc, lewek md. age-related changes in strength, joint laxity, and walking patterns: are they related to knee osteoarthritis? phys ther 2007;87(11):1422-1432. 11. fitzgerald gk, childs jd, ridge tm, irrgang jj. agility and perturbation training for a physically active individual with knee osteoarthritis. phys ther 2002;82:372-382. 12. bennell k, hinman r. exercise as a treatment for osteoarthritis. curr opin rheumatol 2005;17:643-640. 13. diracoglu d, aydin r, baskent a, celik a. effects of kinesthesia and balance exercises in knee osteoarthritis. j clin rheumatol 2005;11:303-310. 14. sekir u, gur h. a multi-station proprioceptive exercise program in patients with bilateral knee osteoarthritis: functional capacity, pain and sensoriomotor function. a randomized controlled trial. j sports sci med 2005;4:590603. 15. rogers mw, tamulevicius n, coetsee mf, curry bf, semple sj. knee osteoarthritis and the efficacy of kinesthesia, balance & agility exercise training: a pilot study. int j exerc sci 2011;4(2),article 5. 16. chamberlain ma, care g, harfield b. physiotherapy in osteoarthrosis of the knees. a controlled trial of hospital versus home exercises. int rehabil med: 1982;4:101-106. 17. reeder ba, chad ke, harrison el, et al. saskatoon in motion: classversus home-based exercise intervention for older adults with chronic health conditions. j phys act health 2008;5:74-87. 18. deyle gd, allison sc, matekel rl, et al. physical therapy treatment effectiveness for osteoarthritis of the knee: a randomized comparison of supervised clinical exercise and manual therapy procedures versus a home exercise program. phys ther 2005;85:1301-1317. 19. barr s, bellamy n, buchanan ww, et al. a comparative study of signal versus aggregate methods of outcome measurement based on the womac osteoarthritis index. j rheumatol 1994;21:2106-2112. 20. bellamy n, buchanan ww, goldsmith ch, campbell j, stitt lw. validation study of womac: a health status instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee. j rheumatol 1988;15:1833-1840. 21. fix aj, daughton dm. human activity profile professional manual. lutz, fl: psychological assessment resources, inc; 1988. 22. irrgang jj, snyder-mackler l, wainner rs, fu fh, harner cd. development of a patient-reported measure of function of the knee. j bone joint surg am 1998;80(8):1132-1145. the south african journal of sports medicine the editor the south african journal of sports medicine po box 115, newlands, 7725 tel: (021) 650-4558 fax: (021) 686-7530 e-mail: mike.lambert@uct.ac.za article submissions: www.sajsm.org.za the views expressed in individual articles and advertising material are the personal views of the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent of the publishers. plagiarism is defined as the use of another’s work, words or ideas without attribution or permission, and representation of them as one’s own original work. manuscripts containing plagiarism will not be considered for publication in the sajsm. for more information on our plagiarism policy, please visit http://www.sajsm.org.za/index.php/sajsm/about/ editorialpolicies editor prof. mike lambert university of cape town editorial board dr kerith aginsky university of the witwatersrand dr theresa burgess university of cape town dr richard de villiers drs van wageningen and partners, somerset west dr lize havemann-nel north west university dr christa janse van rensburg university of pretoria dr louis holtzhausen university of the free state prof. frank marino charles sturt university, australia dr babette pluim royal netherlands lawn tennis association, the netherlands publisher health and medical publishing group 28 main road, rondebosch, 7700 private bag x1, pinelands, 7430 tel: (021) 681-7200 hmpg editor-in-chief janet seggie consulting editor jp de v van niekerk deputy editor bridget farham editorial systems manager melissa raemaekers scientific editor ingrid nye technical editors emma buchanan, paula van der bijl art director brent meder dtp/layout anelia du plessis, carl sampson production assistant neesha hassan head of publishing robert arendse head of sales and marketing diane smith | tel: (012) 481-2069 repro & printing creda communications the south african journal of sports medicine contents editorial 34 first principles: reasons to always go back m lambert original research 35 body composition and habitual and match-day dietary intake of the fnb maties varsity cup rugby players s potgieter, j visser, i croukamp, m markides, j nascimento, k scott 43 effect of caffeine ingestion on fluid balance during exercise in the heat and during recovery y zhang, s j carter, r e schumacker, y h neggers, m d curtner-smith, m t richardson, j m green, p a bishop 48 associations of objectively and subjectively measured physical activity with trabecular and cortical bone properties in prepubertal children r meiring, j a mcveigh 55 obesity in 7 10-year-old children in urban primary schools in port elizabeth j mckersie, m l baard review 59 dietary supplements containing prohibited substances: a review (part 1) p van der bijl case report 62 chronic exertional compartment syndrome in the forearm of a rower p volcke, j h kirby, p l viviers, j t viljoen 64 cpd questionnaire volume 26 | number 2 | june 2014 mailto:mike.lambert@uct.ac.za http://www.sajsm.org.za http://www.sajsm.org.za/index.php/sajsm/about/ s afr j sports med 2022;34:1-54. doi: 10.17159/2078-516x/2022/v34i1a14885 thursday 29 september – sunday 2 october 2022 poster presentations index name abstract title a1 ms caeleigh king concussion injury management in amateur hockey players a2 mrs audrey jansen van rensburg chronic disease and allergies are associated with iliotibial band syndrome (itbs) in distance runners: a cross-sectional study in 76,654 race entrants a safer study a3 mr david kopping a comparative study investigating the fifa11+ injury prevention programmes for implementation in recreational soccer, tennis and cricket a4 dr elene lourens injury and illness assessment at the 2016 four-day high school netball tournament at waterkloof: a cross-sectional study b2 mr solomon mthombeni an exploration of support systems for elite athletes by south african national sport federations b3 ms jocelyn solomons rhythmic movement as alternative training method for rugby players b4 mr kristian myburg the interand intra-rater reliability of the movement competency screen in experienced and inexperienced raters b5 mr motheo moroane the effects of time of day on isokinetic torque and power during knee extension and flexion: a pilot study c1 mrs belinda adigun detection of doping using ocular-motor deception testing c2 dr gerrit breukelman concurrent low carbohydrate, high fat diet with/without physical activity does not improve glycemic control in type 2 diabetics c3 dr lourens millard visual abilities distinguish level of play in rugby c4 prof habib noorbhai gamification for biokinetics and sports science: enhancing students' clinical skills during distance learning and post covid-19 c5 mrs yolanda stevens exploration of saqa certified rock climbers' perceptions regarding the certification process in south africa d1 mr adiele dube the link between physical activity, sedentary behavior, digital health interventions and risk of type 2 diabetes and diabetesrelated health outcomes: systematic review and meta-analysis d2 ms robynne gilchrist osteoarthritis rehabilitative practices among biokineticists and physiotherapists in south africa d3 ms robynne gilchrist team-based approach to osteoarthritis management: viewpoints of biokineticists and physiotherapists d4 mrs lynn smith physical activity and quality of life of in patients with fibromyalgia a pilot study e1 ms jolandi jacobs prevalence and incidence of injuries among female cricket players: a systematic review and meta-analyses http://dx.doi.org/10.17159/2078-516x/2022/v34i1a14885 e2 prof habib noorbhai an evaluation of how cricketers are coached to bat from junior cricket e3 ms cheryl-ann volkwyn quantifying coaching considerations, attitudes and strategies to player substitutions in school rugby union e4 mrs audrey jansen van rensburg epidemiology of upper limb injuries in the super rugby tournament (2013-2016) f1 mrs lulama mabala employee's perceptions of leisure and retirement during the twelve months before retirement: a descriptive interpretive study in the kenneth kaunda district of the north-west province f2 dr cornelia schreck patterns of participation in campus recreation sport and leisure boredom g1 mr johann els cardiopulmonary exercise testing combined with cardiac rehabilitation exposing additional arrhythmias within aerobic metabolism, potentially due to oxidative stress – is this the missing link in unexplained cardiovascular deaths? g2 dr kobus slabber bertolotti's syndrome: overlooked, under-diagnosed? h1 mr dean baker a comparison of the risk profile for developing illness-related medical encounters in halfand ultramarathon runners h2 dr phoebe runciman eye pathologies in para athletes in the winter settings: an analysis of the sochi 2014 and pyeongchang 2018 paralympic winter games h3 dr phoebe runciman eye pathologies in para athletes in the winter settinga systematic review h4 ms tayla ross an analysis of the partial feasibility of a novel cardiac exercise rehabilitation programme for patients suffering from cardiovascular disease h5 ms mandisa simamane a scoping review examining physical activity interventions for the management of hypertension i1 ms courtenay davis motivation for exercise and the effects of exercise participation on mental health during the covid-19 lockdown in south africa i2 mr abdul hamid jalal physiological risk profiles of asymptomatic males performing the salaah (islamic prayer) as a low-intensity physical activity i3 mrs robyn klaasen barriers to participation in sport among urban adolescents attending an international school in cape town, south africa i4 mrs robyn klaasen the relationship between barriers to participation in sport for adolescent learners and the grade (scholastic year) in which they are enrolled: a case study in an international school in cape town, south africa j1 dr henriette hammill relationships between ground reaction force, isokinetic knee strength, and the incidence of lower extremity injuries in university-level netball players j2 dr mariaan stofberg kinematic gait comparison between back-carried-, and non-backcarried setswana-speaking children j3 mr dimitrije kovac effect of 6 weeks functional intervention program on fms score and the relationship with the hop test in female netball players j4 mr clinton swanepoel morphological characteristics and their relationships to performance in male cross-country runners k1 dr koketjo tsebe psychological factors affecting physically disabled athletes in south africa k2 dr cindy kriel the perceptions of primary caregivers on the social skills and recreational activities of children aged 10-12 years with down syndrome k3 prof peet du toit effect of limitless you peak performance program on the brain, health and skill-related fitness of netball players k4 prof habib noorbhai the effects of the covid-19 lockdown on physical, mental, and emotional parameters among regular sports persons l1 dr laura gray effects of social context on handgrip strength performance among less active people living with hiv l2 prof mariette swanepoel the effect of psycho-social health on the coronary heart disease risk index among employees in a financial institution of south africa m1 prof timoteo daca physical activity and physical fitness of older adult women from urban and peri-urban area of maputo-mozambique m2 ms gomes nhaca habitual physical activity in children and young from urban and rural areas of mozambique m3 mr jorge uate physical activity levels of adult male and female from a peri-urban area of maputo-mozambique m4 dr laura gray effects of the emerging non exerciser stereotype on performance on a fatiguing task in active and less active healthy young adults a1: concussion injury management in amateur hockey players caeleigh king1, heather morris-eyton1 university of johannesburg1 cking@uj.ac.za background: hockey has a high potential for sports related concussion injuries due to intrinsic and extrinsic factors associated with the rules and equipment of the game. this is despite hockey being classified as a non-contact sport. symptoms of concussion are diverse and may have a delayed presentation contributing to a high number of sports related concussions that are overlooked and not detected. undiagnosed concussion injuries may result in adverse health complications and contribute towards long-term neurological conditions. multiple concussion injuries and sub concussive impacts may have a cumulative effect or threshold dose effect contributing to neurodegenerative diseases. concussion injury protocols are imperative to improve the detection, management, and outcomes of sports related concussion injuries. however, hockey concussion injury protocols are insufficient compared to other sports such as rugby. methodology: this study was a partially mixed sequential dominant status design (quant qual), divided into two phases. in phase one a modified rockas-st questionnaire was conducted with hockey players and officials. in phase two a focus group discussion with umpires and interviews with coaches were conducted. results: of 101 field hockey players 18,8% were diagnosed with a sports related concussion between march 2018 and march 2022. of this population 35.6% reported having a concussion before march 2018. injuries to the shoulder, neck, head, and face were reported as: 98 stick related injuries; 102 ball related injuries; 187 collision related injuries. however, only 20 of these reported injuries resulted in a concussion suggesting that a large number of concussion injuries were overlooked, undetected or not reported at the time of injury. of those players diagnosed with a concussion, 27,7% continued to play following the injury either because it was an important game or the injury severity was not detected. coaches and umpires recognised that potential concussion incidents required educational intervention to improve on field diagnosis and management. conclusion: from the total number of reported hockey related injuries (n=387), only 20 (5,2%) were identified as concussion. this could indicate a gap in the knowledge regarding concussion injury detection and on field management. it is imperative that concussion protocols are developed to support player welfare mailto:cking@uj.ac.za a2: chronic disease and allergies are associated with iliotibial band syndrome (itbs) in distance runners: a cross-sectional study in 76,654 race entrants – a safer study jandre v. marais1, 2, audrey jansen van rensburg1, martin p. schwellnus2, 3, 4, catharina c grant2, esme jordaan5, 6, pieter boer7 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa1, sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa2, emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa3, international olympic committee (ioc) research centre, south africa4, biostatistics unit, medical research council, south africa5, statistics and population studies department, university of the western cape, south africa6, department of human movement science, cape peninsula university of technology, south africa7 drjmarais@outlook.com background: iliotibial band syndrome (itbs) is a common gradual onset running-related injury affecting the lateral side of the knee in distance runners. risk factors associated with itbs are sparsely researched. this cross-sectional study aims to identify the risk factors associated with itbs in distance runners that entered the 21.1km and 56km two oceans marathon races (2012-2015). methodology: in total, 76654 runners (71.8%) of the 106743 race entrants who completed the online pre-race medical screening questionnaire, consented to the study. among them, 60635 were noninjured, and in 1314 runners an itbs injury was verified by a health care professional. risk factors associated with itbs were explored using uni& multiple regression analyses: demographics (race distance, sex and age groups), training/running variables, history of existing chronic diseases (including a composite chronic disease score) and any allergy history. prevalence (%, 95%ci) and prevalence ratios (pr) are reported. results: the 12-month period prevalence of itbs in marathon runners was 1.58% (1.49-1.68). independent risk factors (adjusted for sex, age group and race distance) associated with a history of itbs were a higher chronic disease composite score (pr=2.38 times increased risk for every two additional chronic diseases; p<0.0001) and a history of allergies (pr=1.90; p2; univariate analysis) significantly associated with a history of itbs were: any git disease (pr=3.11; p<0.0001); any haematological/immune disease (pr=2.79; p=0.0038); any kidney/bladder disease (pr=2.56; p=0.0002); any nervous system/psychiatric disease (pr=2.25; p<0.0001); any respiratory disease (pr=2.23; p<0.0001); any symptoms of cvd (pr=2.16; p=0.0106). a significantly lower prevalence of a history itbs injury is reported for runners with more years of recreational running (pr=0.94, a 6% decrease in risk for every 5-year increase in running; p=0.0009) and a slower average running speed (pr=0.98, a 2% decrease in risk for every 1 km/hr decrease in running speed; p=0.0066). conclusion: the novel independent risk factors associated with a history of itbs in distance runners are an increased number of chronic diseases and a history of allergies. identifying athletes at higher risk for itbs can guide healthcare professionals in their prevention and rehabilitation efforts. mailto:drjmarais@outlook.com a3: a comparative study investigating the fifa11+ injury prevention programmes for implementation in recreational soccer, tennis and cricket david kopping1, dylan bennett1, habib noorbhai1 department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa1 davidmkopping@gmail.com background: sports injuries have long since plagued professional and recreational athletes alike. the risk of injuries sustained by recreational athletes may be reduced through effective injury prevention programme’s (ipp’s) performed prior to exercise. the fifa 11+ and fifa 11+ shoulder (11+s) are ipp’s that were designed and have been effectively implemented in professional soccer. however, a gap in the literature exists as standardised ipp’s designed for tennis and cricket are a scarce resource. this study aimed to identify whether these ipp’s would be efficacious in reducing the risk of injury for recreational athletes across multiple sporting codes in south africa. methodology: an online questionnaire was distributed to recreational athletes. valid responses were recorded (n = 64). chi square tests were conducted to determine the correlation between coaches discussing injury prevention techniques and the participant’s injury outcome. chi-square tests were also conducted to determine whether a relationship existed between a participant’s warm-up routine and pain experienced during sports participation. results: over half (52%) of the participants reported having a sports-related injury within three months prior to their questionnaire completion. furthermore, a combined 34% of participants reported experiencing pain whilst performing their respective sport. a resounding 86% of the participants were unfamiliar with the fifa 11+ ipp, yet 48% of the participants reported always warming up prior to exercise. the ankle joint was most prevalently injured in soccer players (91%) while the knee/patella was the most prevalent injury site (67%) in tennis players. surprisingly, 42% of cricketers reported having neurological symptoms (numbness or tingling) down one or both legs. additionally, 25% of cricketers also reported experiencing lower back pain. conclusion: this study’s questionnaire responses revealed that recreational players do perform a warmup routine prior to exercise, yet sustained injuries occur regardless. therefore, the fifa ipp’s should be considered to standardise warm up programmes for recreational sports participation in south africa. mailto:davidmkopping@gmail.com a4: injury and illness assessment at the 2016 four-day high school netball tournament at waterkloof: a cross-sectional study elene lourens1, audrey jansen van rensburg1, tanita botha1, dina christa janse van rensburg1 university of pretoria1 elenelourens@gmail.com background: netball is growing in popularity with increasing numbers of participants at the school level. this expands the talent pool but may lead to more competitive play and more netball-related medical encounters. this study aimed to determine the period prevalence, incidence, type and diagnosis of injuries and illnesses in female netball players during the 2016 four-day waterkloof high school netball tournament. methodology: this cross-sectional observational study involved all participating female youth netball players (n=875) from 41 high schools and 125 teams (u/14 u/19). players suffering from an injury or illness were assessed in the medical tent by a medical practitioner who completed an injury/illness data collection sheet. main outcome measures included: 1) injury and illness period prevalence (pp: %), 2) injury incidence (i: per 1000 match player-hours) for anatomical region, body area, tissue type, pathology type and specific diagnosis, and 3) illness incidence (i: per 1000 match player-days) for organ system, region, symptom cluster and aetiology of illness. results: in total, 239 players sustained 262 match injuries (pp=27.31%). the incidence of all injuries was 48.13. lower limb injuries were the most common (i=30.49). the most frequent body area involved was the ankle (i=12.12) followed by the knee (i=9.00) and the foot (i=5.69). ligament/joint capsule was the most common tissue type involved (i=13.59). joint sprains (i=13.59) are attributed to the highest pathology type, primarily presenting as ankle sprains (i=10.84) of the lateral ligament (i=6.43). a total of 42 players contracted 42 illnesses (pp=4.80%). the incidence of all illnesses was 12.0. the dermatological system (i=3.71) was the most common system affected, followed by the respiratory system (i=1.71). itchy lesions were the most frequent symptom reported (i=3.43). most illness encounters are associated with exercise-related causes. conclusion: the lower limb specifically the ankle was the most frequently affected body area. ligament/joint capsule was the most common tissue type involved, lateral ankle sprains were the most common diagnosis. the dermatological system was most commonly affected followed by the respiratory system. injuries were more prevalent than illness. knowledge of injury and illness epidemiology will enable the development of preventative measures to reduce injury/illness patterns at youth netball tournaments. mailto:elenelourens@gmail.com b2: an exploration of support systems for elite athletes by south african national sport federations solomon mthombeni1, habib noorbhai1, yoga coopoo1 sport and movement studies, faculty of health sciences, university of johannesburg1 smthombeni.solly@gmail.com background: athletic success at major events such as the olympic games is of significant importance and value to elite athletes, sports coaches, various stakeholders and nations. the purpose of the study was to examine the availability of elite sport support systems by the south african national sports federations (nsfs) and whether support systems were extended and accessible to elite athletes from historically disadvantaged areas. methodology: the paper was a descriptive study in which analytical methods were employed. a total of 21 nsfs with olympic sporting codes participated in the study whereby they responded to a survey questionnaire in line with sports policy factors leading to sporting success (spliss, 2015) on support systems for elite athletes. descriptive statistical analyses were conducted using statistical package for social sciences (spss version 27.0) and arranged into customised tables of frequencies. results: in terms of the overall availability of support systems for elite sports by nsfs, the majority of federations reported overall insufficiencies in the following pillars of support (overall vs. historically disadvantaged areas); financial resources 11.6±8.8 vs. 9.8±10.5 (61.9% vs. 66.7%), scientific research support services 11.8±7.1 vs. 7.8±9.1 (52.4% vs. 61.9%), followed by post-sport career support 11.8±6.6 vs. 9.6±9.4 (47.6% vs. 66.7%), and sports facilities 14.2±9.2 vs. 9.6±9.4 (23.8% vs. 66.7%). in terms of elite sport support systems, nsfs reported moderate to high sufficiency of the following support systems; coach provision and development programmes 14.2±9.2 (90.5%), organisational structure and sports policies 14.2±9.2 (81%), and opportunities for international competitions 14.2±9.2 (81%). conclusion: the insufficiency of support systems was worse for elite athletes from historically disadvantaged areas in all the nine pillars of support systems, with provision for sport infrastructure being among the highest insufficiencies reported by nsfs. the nsfs reported having sufficient organisational and sport policy structures in place, as well as provision for access to international competitions. however, more provision is required to ensure that organisational structure and sport policies are more inclusive towards athletes from historically disadvantages areas. these additions in support systems may contribute ultimately to better outcomes in performance, and broadening the pool of athletes performing for south africa. mailto:smthombeni.solly@gmail.com b3: rhythmic movement as alternative training method for rugby players jocelyn solomons1 stellenbosch university1 jocelynjsolomons@gmail.com background: the inclusion of other non-traditional approaches to training has become more popular within rugby conditioning. rhythmic movement, also referred to as “dance”, involves the execution of different motor skills, the integration and sequencing of actions between limbs, timing and spatial precision. it requires performing movement tasks to auditory rhythmic patterns and as a multifaceted activity, it depends on a large number of elements with direct and indirect effects on the physiology and physical attributes of a player. in terms of rugby conditioning, the common belief dictates that fitness or conditioning elements should be developed through focused, isolated training blocks. the technical, tactical and physical conditioning for rugby has primarily consisted of traditional, rugby-based approaches to training as indicated by the majority of current research. however, in order for rugby coaches and specialist coaches to gain a competitive edge over opposing teams, they need to find new innovative ways to adapt their training methods and programmes in order to accommodate the changes to the profile of the game. the primary aim was to investigate the effect of a rhythmic movement intervention on selected bio-motor skills of rugby players in the western province rugby union academy methodology: the current study was based on a crossover experimental design. a crossover trial involves two treatments, which are administered consecutively to all the participants recruited for the study. the main purpose served by this study design was to provide a basis for separating treatment effects from period effects and to establish whether the intended outcome(s) of the intervention materialised. this separation was achieved by calculating the treatment effects separately in two sequence groups, which is done by the process of randomisation. in this design, pre-post changes in the experimental group were directly compared to changes in the control group to indicate the effects of the intervention. crossover trials require a washout period to ensure that baseline data are comparable. the reversibility of a treatment effect is a prerequisite for applying a crossover design and determines the length of the washout period. academy rugby players (n = 54) from the western cape, south africa (age 18 0.81 years; height 1.76 0.69 cm; weight 76.77 10.69 kg), were conveniently selected to participate in this study. during the pre-and post-test, all the participants were tested on various fitness elements in a field testing order. the rhythmic movement programme was conducted and choreographed by the primary researcher who is a professional dancer and choreographer. in order to compile the intervention, the primary researcher looked at the most common movement patterns and exercises of rugby players by studying match footage. the intervention consisted of 32, 60 minute sessions over a period of 16 weeks (2 x 8 weeks). these sessions were part of their weekly planning and were not extra sessions. each session started with a 10-minute progressive aerobic endurance rhythmic movement routine as a warm-up. the warm-up was followed by 45 minutes of learning new rhythmic movement exercises and repeating them to music, which concluded with a 5minute cool-down which involved progressive stretching. the data was analysed using descriptive statistics (standard deviations and means). a series of one-way anova with post hoc lsd t-tests were used to examine between-group (tca versus ctb group) differences. statistical significance at 5% (p 0.05) were highlighted (in cases where p = 0.06). mailto:jocelynjsolomons@gmail.com results: results indicated a statistically significant improvement (p < 0.05) in agility2 (p = 0.06), power2 (p = 0.05), local muscular endurance1 (p = 0.01) & 3 (p = 0.01) and dynamic balance (p < 0.01). likewise, forwards and backs also showed statistically significant improvements (p < 0.05) per positional groups. conclusion: therefore, a rhythmic movement intervention has the potential to improve rugby-specific bio-motor skills and improve positional-specific skills should it be designed with positional groups in mind. future studies should investigate, not only the effect of rhythmic movement on improving specific rugby bio-motor skills but the potential of its application as an alternative training method during offseason (or detraining phases) or as a recovery method. b4: the interand intra-rater reliability of the movement competency screen in experienced and inexperienced raters kristian myburg1, bradley hornsey1, christiaan jordaan1, helen bayne1 department of physiology and sport, exercise medicine and lifestyle institute, faculty of health sciences, university of pretoria1 kristian.myburg@semli.co.za background: movement screening is used to predict future performance and identify individuals at increased risk of injury. the movement competency screen (mcs) may be the preferable tool for athletes as it assesses seven fundamental movement patterns at two different loading levels and makes use of video cameras, purportedly to enhance the reliability of rating. movements are rated subjectively based on specified criteria and, therefore, experience in rating the test may influence scoring. the aim of the study was to assess interand intra-rater reliability in a group of diversely experienced sports scientists in conducting the mcs with adolescent athletes. methodology: three experienced (>2 years in conducting the test) and three inexperienced (<1 year) raters scored 10 mcs videos on two occasions separated by three weeks. each movement was rated on a scale of 1 to 5, with a possible total of 50. kendall’s coefficient of concordance (w) was used to assess inter-rater reliability for each movement and the total score. intra-rater reliability was assessed using the kappa statistic for each movement and the intra-class correlation coefficient (icc) for the total. results: inter-rater reliability was similar in both groups of raters, with a moderate agreement for most of the movements (mean w; experienced: 0.58 on day 1, 0.59 on day 2; inexperienced: 0.58 on day 1, 0.62 on day 2). however, the intra-rater reliability was substantially higher in the experienced raters (icc for total scores of 0.64 compared to 0.25 in the inexperienced), demonstrating a better consistency across the two tests. conclusion: inter-reliability was only moderate for both the experienced and inexperienced raters. care should therefore be taken when multiple raters are involved in assessing groups of athletes. intra-rater reliability appears to be affected by the testing experience. it is therefore recommended that thorough training is emphasised and that practitioners working in a team should regularly collaborate on implementing the mcs to improve agreement between raters. mailto:kristian.myburg@semli.co.za b5: the effects of time of day on isokinetic torque and power during knee extension and flexion: a pilot study motheo moroane1, jonathan davy1 department of human kinetics and ergonomics, rhodes university1 motheomoroane@yahoo.com background: time of day influences both physical and cognitive performance. this influence may have further implications for when coaches or clinicians schedule assessments involving isokinetic dynamometry when attempting to quantify strength and power. the aim of this study, therefore, was to determine the effects of time of day on isokinetic measures of strength and power. methodology: through a repeated measures experimental design, this study assessed the time of day effects on isokinetic peak torque, average peak torque, and average variables during knee extension and flexion at angular velocities of 60˚/s and 180˚/s using the isokinetic dynamometer system 4 pro. 10 healthy student participants completed three testing sessions over six days. the three experimental conditions were in the morning (08h00-09h00), afternoon (13h00-14h00), and evening (18h00-19h00). five repetitions of isokinetic knee extension and flexion were performed at each velocity, with a 60-sec break between testing velocities. a one-way analysis of variance was applied to compare the three times of day with a tukey post hoc test applied when relevant. results: during knee extension at 60˚/s, peak torque (p=0.01) and average peak torque (p=0.03) were significantly higher in the evening relative to other times of the day. no other statistically significant differences were reported for either knee extension at 60˚/s or knee extensions at 180˚/s and knee flexion at 180˚/s. although no significant differences were found for these variables, there was a trend towards greater torque and power variables in the afternoon and evening for knee extension and knee flexion. conclusion: the findings indicate that time of day does have an impact on torque produced at lower velocities, but not higher velocities. it is therefore crucial for researchers, practitioners, and highperformance specialists to factor these effects when using isokinetic dynamometry to ensure that accurate measures are obtained, particularly when testing for maximum torque production during isokinetic dynamometry mailto:motheomoroane@yahoo.com c1: detection of doping using ocular-motor deception testing belinda adigun1, jeroen swart1 research centre for health through physical activity, lifestyle and sport (hpals), dept of human biology, faculty of health sciences, university of cape town1 belinda.adigun@gmail.com background: the manipulation of haemoglobin mass has been used by athletes to enhance performance. the adaptive biological passport assesses haematologic markers for patterns indicating a high probability of doping. athletes use counter-measures to subvert testing, thus requiring a detection method independent of haematologic variables. ocular-motor deception testing (omdt) utilises automated pupillometry and eye movement tracking to detect deception in subjects. the objective of this study is to investigate the sensitivity and specificity of omdt in the detection of doping, as an independent marker. methodology: this sham study is designed to replicate a typical 12-week training season for athletes leading up to a major competition. we employed a randomised, single-blinded, control study. twenty subjects were randomised into a control or doping group and provided with a standard 12-week cycling training program. subjects in the doping group received placebo capsules under the guise of a performance-enhancing substance (pes), for the duration of the training program. omdt was performed at weeks 1, 8, 13 and 20 to establish the washout period. all subjects were monetarily incentivised to evade detection. a repeated measures anova, and post hoc bonferroni analysis was conducted to compare the two groups over time and between each time point. results: the two groups responded differently over time (p=0.0251; f(3,9)=5.071). omdt testing performed on week 8 (during the consumption of placebo) resulted in (mean  sd (range)) scores of 79.75  10.8 (64 – 88) for the control group and 35.8  15.5 (1749) for the doping group respectively. at a threshold value of 50, all of the subjects in the doping and control groups recorded below and above the threshold respectively. however, data from before the commencement, and after the cessation, of pes did not result in similar uniform outcomes. conclusion: results suggest that omdt can reliably detect deceptive behaviour while subjects are taking pes. however, 8 weeks after treatment is discontinued, omdt no longer discriminates between subjects in the doping and control groups. overall, results suggest that omdt could potentially be used as an indirect detection method to identify athletes for further investigation into potential drug use. mailto:belinda.adigun@gmail.com c2: concurrent low carbohydrate, high fat diet with/without physical activity does not improve glycemic control in type 2 diabetics gerrit j breukelman1, albertus k basson2, trayana g djarova2, cornelia j du preez3, ina shaw1, heidi malan4, brandon s. shaw1 university of zululand, department of human movement science1, university of zululand, department of biochemistry and microbiology2, university of zululand, department of consumer sciences3, richards bay, caredoc4 breukelmang@unizulu.ac.za background: this study aimed to determine if a low carbohydrate, high fat diet (lchfd) provides any benefits of glycemic control in patients with type 2 diabetes mellitus, either alone or in conjunction with physical activity. methodology: type 2 diabetics (n = 39) were assigned into either a concurrent physical activity and lchfd group (diexg), lchfd only group (dietg), or control group (cong). results: no significant (p > 0.05) changes were observed in glycated hemoglobin (hba1c), glucose and insulin in either the diexg (hba1c: p = 0.592; 8.3% decrease, glucose: p = 0.477; 11.1% decrease and insulin: p = 0.367; 44.1% increase) or dietg (hba1c: p = 0.822; 0% change, glucose: p = 0.108; 11.0% decrease and insulin: p = 0.976; 4.2% decrease). conclusion: in this study, neither a lchfd alone nor in combination with a physical activity programme succeeded in eliciting improvements in insulin sensitivity in the type 2 diabetics. as such, adoption of a lchfd, either alone or in combination with physical activity, should not unequivocally be part of the treatment approach for type 2 diabetics. furthermore, it should carefully be weighed against the benefits of more balanced dietary and/or physical activity interventions. mailto:breukelmang@unizulu.ac.za c3: visual abilities distinguish level of play in rugby lourens millard1, brandon s. shaw1, gerrit-jan breukelman1 ina shaw1 university of zululand1 millardl@unizulu.ac.za background: novices in sport possesses similar visual skills to that of experts however, there may be major differences in the magnitude of performance in these skills, with expert athletes only demonstrating superiority in specific vision skills and not all aspects of vision. methodology: the present study compared the performance of premier league rugby players (n = 40) and first division rugby players (n = 40) on six specific components of vision, namely; accommodation facility, saccadic eye movement, speed of recognition, peripheral awareness, visual memory, and handeye coordination. results: premier league rugby players performed significantly (p = 0.001) better than the first division rugby players in five of the six tests. but were found to be similar in visual memory performance (p = 0.810). conclusion: while this study substantiates the proposal that expert athletes, and specifically rugby players, have superior visual expertise to novice athletes, this study also found that this is not the case with all vision skills. the present study’s findings suggest that sport-specific vision testing batteries may be required to distinguish high performers from low performers in the same vein as physical tests are utilised in the selection and recruitment of athletes. mailto:millardl@unizulu.ac.za c4: gamification for biokinetics and sports science: enhancing students' clinical skills during distance learning and post covid-19 habib noorbhai1, simone ferreira1 faculty of health sciences, university of johannesburg1 habibn@uj.ac.za background: during the covid-19 pandemic and lockdown levels, it has been a challenge to teach clinical skills and competencies to students due to restrictions on campus and with the influx of students (and their families) becoming infected with the virus. this has propelled universities to become innovative and creative with clinical skills in teaching, learning and assessment. methodology: this teaching approach has been successfully conducted in other countries through the use of simulated-based learning. however, this has not been the ideal option for a student cohort in south africa due to three main challenges: 1) connectivity issues for certain students, 2) lack of fun and excitement, and 3) lack of infrastructure in the current biokinetics clinic to enable a telehealth approach. one way in which these challenges have been mitigated is through the adoption of gamification (a 3d game) as a teaching approach. such an approach has been proven useful in medical teaching and is aligned with the fourth industrial revolution (4ir) imperatives. results: gamification or game development in teaching is a design-based research approach that includes futuristic development perspectives. in our study, patient case studies and scenarios through gamification have been developed, namely: 1) blood pressure and heart rate, 2) ecg, 3) cycle ergometer test, 4) isokinetic knee flexion/extension, and 5) isokinetic shoulder flexion/extension. these scenarios within the game, factor in the integrations of various lab-based instruments (in 3d) used in biokinetics practice (examples: the isokinetic machine for orthopaedic rehabilitation, the cycle ergometer for cardiorespiratory screening and fitness, etc). the work-integrated learning (wil) programme would also be followed and be aligned to these procedures. these procedures have been written as patient scenarios and case studies and have been converted into an interactive gaming solution to assist students with clinical learning, reasoning, skills competencies and assessment of these competencies. conclusion: the game can be accessed via blackboard (uj’s learning management system). thereafter, a virtual reality (vr) approach will be adopted and user-friendly vr devices will be integrated with mobile phones for students to seamlessly utilise and apply. furthermore, the game will also be deployed as a mobile application on itunes and googleplay. mailto:habibn@uj.ac.za c5: exploration of saqa certified rock climbers’ perceptions regarding the certification process in south africa yolanda stevens1, minette strauss1, yolanda stevens1, j. theron weilbach1 leisure studies1 11939044@nwu.ac.za background: as individuals engage in progressively more recreational activities, the south african rock climbing industry has shown tremendous growth. the growth brings about numerous safety challenges that specifically relate to skills, experience, and equipment. due to the limited number of qualified south african guides who specialise in rock climbing as an adventure activity, this research aimed to explore the perceptions regarding the saqa guiding qualification process to identify any difficulties or hindrances facing rock climbers. methodology: to explore qualified guides’ perceptions, a qualitative descriptive design was implemented, and semi-structured interviews were conducted with five saqa qualified rock climbing guides in sa. the interview data were analysed and categorised using an inductive content analysis approach. results: from the findings, three themes, namely legality in climbing, fundamentals and climbing culture emerged as themes. it became clear that there is uncertainty regarding the requirements for legal guidance. there are also concerns about the fundamental requirements in the saqa process, the south african qualification process is different to that of other countries and the perception about the saqa guiding qualifications can be perceived as inferior. lastly, the climbing culture contributes to the attitudes climbers have towards the saqa process. if the correct information about the saqa qualification is available, the perceptions of the qualification might become more positively persuaded. conclusion: to improve the perceptions towards the saqa qualification, a single governing body that regulates all training courses and programmes that are available in sa, should be established. hereby, the qualification can be regulated and monitored in a professional structured manner. this will ensure that adventure guiding in sa is considered as a professional career path from which a person could earn a living and prevent unqualified guides from operating illegally. mailto:11939044@nwu.ac.za d1: the link between physical activity, sedentary behavior, digital health interventions and risk of type 2 diabetes and diabetes-related health outcomes: systematic review and meta-analysis adiele dube1, mathunjwa m1 university of zululand1 dubea2567@gmail.com background: there are more than 4 million people diagnosed with type 2 diabetes in south africa, which costs the nhd zar 24.5 billion if both diagnosed and undiagnosed patients are considered. this disease significantly increases the risk of cardiovascular disease and reduces the quality of life. however, little is known about the link between physical activity, sedentary behaviour, digital health interventions and risk of type 2 diabetes and diabetes-related health outcomes. to systematically review the evidence and correlate the effect of physical activity, digital health interventions, sedentary behaviour and risk of type 2 diabetes and diabetes-related health outcomes. methodology: electronic databases including pub med, medline, ebscot, embase, cinahl, psycinfo, sport discus, science direct and web of science were searched for current and completed interventional trials investigating the effect of either effect of physical activity, digital health interventions, sedentary behaviour and risk of type 2 diabetes and diabetes-related health outcomes. search terms included medical subject heading (mesh) terms and text words. results: identified were 720 full texts and 12 studies with 450, 769 included. higher total physical inactivity, sitting time, and sedentary behaviour were associated with a significant risk of obesity (hr=1.27, 95% ci=1.21 – 1.29, p<0.001) and type 2 diabetes mellitus (hr=1.17, 95% ci=1.03 – 1.25, p<0.001). the increased risk of t2dm was attenuated by a reduction of total daily sitting time and adjusted physical activity but remained significant (hr=1.14, 95% ci=1.02 – 1.16, p<0.001). aor metaanalysis of the 5 studies showed that higher t2dm rates in women (or=1.57, 95% ci=1.42 – 1.76, p<0.001) compared to their male counterparts (or=1.36, 95% ci=1.31 – 1.52, p<0.001) but no differences for t2dm in within age groups. conclusion: evidence showed that reducing total daily sitting time (i.e. sedentary behaviour) is associated with a reduced risk of t2dm as well as improved glycaemic control in patients already diagnosed with the disease. there is consistent evidence that breaking up sitting time with short, frequent bouts of light-intensity physical activity improves metabolic biomarkers over the course of a single day. mailto:dubea2567@gmail.com d2: osteoarthritis rehabilitative practices among biokineticists and physiotherapists in south africa robynne gilchrist1, 2, 3, aayesha kholvadia1, 2, 3, 4 nelson mandela university1, biokinetics association of south africa2, health professions council of south africa3, south african sports medicine association4 s214051196@mandela.ac.za background: a multifaceted condition such as osteoarthritis is ideally suited to the realm of multidisciplinary management which focuses on holistic patient care. although a biopsychosocial approach to osteoarthritis management has been proposed, there is however a lack of adherence to evidence-based guidelines which is a concern previously found in the south african healthcare system. therefore, the aim of this study was to evaluate and describe osteoarthritis rehabilitative practices among biokineticists and physiotherapists, thereby identifying current trends in osteoarthritis management. methodology: a descriptive methodology with a cross-sectional study design and a convenience sampling technique was used. the target population consisted of biokineticists and physiotherapists located within the south african public and private healthcare sectors. a self-developed, contentvalidated, online questionnaire surveyed rehabilitative professionals’ management modalities and patient referral trends. results: physical exercise (94%) was the most prescribed therapy for osteoarthritis patients among biokineticists and physiotherapists. almost all biokineticists (89%) and physiotherapists (87%) stated that they refer osteoarthritis patients. biokineticists (55%) and physiotherapists (50%) would most likely refer an osteoarthritis patient to a specialist medical practitioner. notably, the majority of biokineticists (55%) also indicated that they would most likely refer an osteoarthritis patient to a physiotherapist. conclusion: understanding the various rehabilitative practices and the unique role of each profession could guide practitioners regarding ways to create and promote an environment conducive to a holistic approach to osteoarthritis management facilitated by referral systems that fit with the theory of a biopsychosocial approach. mailto:s214051196@mandela.ac.za d3: team-based approach to osteoarthritis management: viewpoints of biokineticists and physiotherapists robynne gilchrist1, 2, 3, aayesha kholvadia1, 2, 3, 4 nelson mandela university1, biokinetics association of south africa2, health professions council of south africa3, south african sports medicine association4 s214051196@mandela.ac.za background: there are challenges within healthcare systems when providing the appropriate continuum of care to address the complexity of patients with osteoarthritis. the range of outcomes and multitude of symptoms and etiologies associated with osteoarthritis calls for a team-based approach for optimal management. rehabilitative professionals are encouraged to collaborate with professionals from diverse health professions to deliver quality patient care. however, there is little published evidence exploring their perceptions of a team-based approach. the purpose of this study was to determine and describe the viewpoints of biokineticists and physiotherapists regarding a team-based approach to osteoarthritis management in rehabilitative medicine. methodology: a descriptive methodology with a cross-sectional study design and a convenience sampling technique was used. the target population consisted of biokineticists and physiotherapists located within the south african public and private healthcare sectors. a self-developed, contentvalidated, online questionnaire surveyed rehabilitative professionals’ perceptions of a team-based approach to osteoarthritis management. results: solo practices were the most popular description for both physiotherapists (33%) and biokineticists’ (55%) current practice setting. overall communication among team members was viewed as dissatisfactory by physiotherapists (36%) and biokineticists (43%). respectively, 69% and 54% of the physiotherapists and biokineticists felt adequately educated on the scope of practice of various healthcare professions involved in osteoarthritis management. forty-three per cent of participating rehabilitative professionals indicated that they had not been exposed to interprofessional education. conclusion: there are equal perceptions among biokineticists and physiotherapists regarding a teambased approach to osteoarthritis management. awareness of south african rehabilitative professionals’ experiences of a team-based approach could guide best-practice recommendations to enhance organised teamwork to promote service delivery and quality care for the osteoarthritis patient. mailto:s214051196@mandela.ac.za d4: physical activity and quality of life of in patients with fibromyalgia – a pilot study lynn smith1 university of johannesburg1 lynnvr@uj.ac.za background: patients with fibromyalgia syndrome (fms) experience a lower quality of life, largely affecting their social functioning and mental health. physical function has been linked to improvements in self-efficacy and social behaviour and lowered anxiety and depression. the purpose of this research was to determine the relationship between physical activity, quality of life and the impact of fms on diagnosed individuals. the objectives of the study were to determine the likelihood of fms patients participating in physical activity regularly, to determine the relationship between physical activity and overall quality of life, and to determine the relationship between quality of life and the impact of fms on these patients. methodology: this study was cross-sectional, and descriptive and quantitative data were collected. thirty-eight patients with fms completed an online questionnaire of four components. the four main components included demographics, the fibromyalgia impact questionnaire (fiqr), short form-36 (sf36), and the global physical activity questionnaire (gpac). the analysis included descriptives, correlations and statistical significance. the significance levels were set at p ≤ 0.05 and p ≤ 0.0167. results: the results exhibited a high fiqr score and a low sf-36 score, suggesting a negative impact on participants’ quality of life. results do not imply that physical activity had an influence on the fiqr and sf-36 scores, however, little to no statistical evidence exists to support this. conclusion: it was concluded that although fms does have a direct impact on quality of life, the relationships between physical activity, sedentary time, the impact of fms and quality of life were inconclusive. a need for further research on this topic has been identified. mailto:lynnvr@uj.ac.za e1: prevalence and incidence of injuries among female cricket players: a systematic review and meta-analyses jolandi jacobs1, benita olivier1, muhammad dawood2, nirmala perera3 university of the witwatersrand1, sefako mokgatho health sciences university2, australian insititute of sport3 jolandi.jacobs@wits.ac.za background: cricket, a bat-and-ball sport, is becoming popular among women of all ages and abilities worldwide. however, cricket participation carries a risk of injury. injuries negatively affect sports participation, performance, and shortand long-term health and well-being. injury prevention, therefore, is the key to safe, long-term cricket participation as a physical activity goal. methodology: a systematic review and meta-analyses were conducted according to the jbi and prisma 2020 guidelines. databases (including grey literature databases) were systematically searched from inception to august 2021. full-text articles that met the inclusion criteria were critically appraised using jbi-tools, and were extracted and synthesized in the narrative summary and tabular forms. three metaanalyses were conducted and heterogeneity was assessed using the i² statistic and the random effects model. results: of the 4256 studies identified, 23 studies met the inclusion criteria. the risk of bias was low for 21 studies. the injury incidence rate for elite cricket was 71.9 (se 21.3, 95% ci 30.2–113.6) injuries per 1000 player hours, the time-loss injury incidence rate was 13.3 (se 4.4, 95% ci 4.6–22.0) injuries per 1000 player hours, and non-time-loss injury incidence rate was 58.5 (se 16.9, 95% ci 25.6–91.7) injuries per 1000 player hours. the injury prevalence proportions for community to elite cricket was 65.2% (se 9.3, 95% ci 45.7–82.3) and injury prevalence proportions for community cricket was 60% (se 4.5, 95% ci 51.1–68.6). the injury incidence proportions for community cricket was 5.6 (se 4.4, 95% ci 0.1–18.3) injuries per 10,000 participants. elite cricket players were more frequently injured than community cricket players. the most prevalent body regions injured were the shoulder, knee, ankle, foot, and toes, and most were sustained by fast bowlers. injuries to the hand, wrist, and fingers had the highest incidence and were most sustained by fielders. conclusion: the study's findings can help stakeholders make informed decisions about cricket participation by informing and implementing strategies to promote cricket as a vehicle for positive public health outcomes. this review also identified gaps in the available evidence base and addressing these through future research would enhance women’s cricket as a professional sport. mailto:jolandi.jacobs@wits.ac.za e2: an evaluation of how cricketers are coached to bat from junior cricket habib noorbhai1, zaid kola1, jordan stringer1 faculty of health sciences, university of johannesburg1 habibn@uj.ac.za background: cricket batters have been taught certain batting techniques at different levels of the game by a variety of cricket coaches. a number of questions have been raised about the various aspects of batting that were taught to players since they started playing cricket from junior level. since previous research investigated the teachings of coaches, the aim of this study was to evaluate how cricketers were coached to bat since junior cricket. methodology: a mixed-methods research study in which an online survey (using both open and closedended questions) was distributed to cricket players (n = 100) from south africa. the online survey was adapted for use through a previously validated questionnaire used among cricket coaches. pearson’s chi-squared tests were used to determine if there were any significant trends in the answers from the survey. the results of the survey were then coded and transferred to spss (statistical software, ibm, version 27). the level of significance was set at p<0.05. results: this study showed that most cricket players (76%) were shown how to lift their bat while batting by their first cricket coach. it was also discovered that 63% of players were taught to direct their bat towards the off-side instead of towards the wicket-keeper or the stumps, while 43% of players (χ2 = 17.54, df = 6, p = 0.008) were taught to have an open face when directing their bat. it was revealed that in most cases (42%; χ2 = 11.65, df = 6, p = 0.7), the player adapts their technique, while 27% of participants do not adapt their technique for the different formats of cricket. conclusion: recommendations from this study include the emphasis on the lateral batting backlift technique (lbbt) as it has been shown to be the more successful backlift and a prominent characteristic of cricket batters at the highest level. despite a number of available coaching aids to assist in the training of junior cricketers, players should be allowed to express themselves individually. further research (and a policy) is required to compile a coaching framework to teach other elements of the batting technique to assist in cricket batting coaching. mailto:habibn@uj.ac.za e3: quantifying coaching considerations, attitudes and strategies to player substitutions in school rugby union cheryl-ann volkwyn1, andrew green1, rian lombard1 university of johannesburg1 cherylv@uj.ac.za background: rugby is a high-intensity, intermittent collision sport played by fifteen players on each team and requires highly specialised playing positions. due to these physical demands and to maintain a highly competitive level, coaches may substitute no more than eight players during the match. player substitutions can affect the match’s outcome and, knowing when to substitute players, is largely determined by a coach’s intuition. therefore, the coach’s involvement and decisions behind player changes must be assessed, as the effects of substituting a player can be either positive or detrimental to the team’s performance. methodology: a six-sectioned questionnaire was developed in conjunction with five university and professional coaches and aimed to assess various issues surrounding player substitutions. the six sections included demographics, reasons for substituting players, considerations, informing players, match progression and status. question responses followed a five-point likert scale. a total of sixty-nine age-group level rugby coaches (experience 11.7 ± 9.0 years) completed the questionnaire. results: common responses indicated that coaches used substitutions to increase their teams’ chances of winning and to reduce player load. additionally, the results indicate that coaches are likely to substitute players based on a predetermined strategy and to manage player loads. coaches were likely to change players following a team scoring and as the game progressed. additionally, substitutions were more likely when game importance increased. responses indicated that coaches frequently inform players with adequate time prior to substitutions. the most frequent time of communication occurred during half-time. finally, coaches frequently considered the technical abilities of the players, timing and score of the game before changing players. conclusion: the results provide a likely indication that coaches rely on their own previous playing experience regarding their decision-making approaches. as this data were collected from school-level rugby teams, it is likely that coaches afforded player game time closer to the completion of a winning match. importantly, substitutions are planned and not reactive. overall, coaches should provide sufficient notice and instruction to replacement players. improved substitution timing could occur when coaches are made aware of and respond to visual clues of players’ performances to enforce substitutions. mailto:cherylv@uj.ac.za e4: epidemiology of upper limb injuries in the super rugby tournament (2013-2016) tshegofatso gaetsewe1, 2, audrey jansen van rensburg1, martin p. schwellnus2, 3, 4, christa janse van rensburg1, charl janse van rensburg5, esme jordaan5,6 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa1, sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa2, emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa3, international olympic committee (ioc) research centre, south africa4, biostatistics unit, medical research council, south africa5, statistics and population studies department, university of the western cape, south africa6 tgaetsewe@hotmail.com background: rugby is a contact and high-impact collisions sporting code, with a high risk of causing acute or long-term injury. this study aimed to determine the incidence and nature of upper limb injuries sustained by elite rugby players during the annual super rugby tournaments (2013 to 2016). methodology: this study was a cross-sectional analysis of data collected prospectively among 868 rugby players from six south african teams who participated in the annual super rugby tournament. team physicians collected daily injury data including the size of the squad, the type of day, player position, whether it was a training or match injury, hours of play (training and matches). other data collected include body area, tissue type, severity (days lost), mechanism of injury (contact vs. non-contact), and phase of play. the incidence (per 1000 player days; 95% ci) and illness burden (ib: days lost due to injury per 1000 player-days) are also reported results: a total of 776 rugby-related injuries were recorded during the study period, of which upper limb injuries accounted for 20.8% of all rugby injuries with an incidence of 2.1 per 1000 player days (95% ci: 1.8-2.5); 2). the incidence of upper limb injuries sustained during match-play was 23.3 per 1000 player days (95% ci: 19.8-27.3), forwards incurred 57.2% and backs 42.8% upper limb injuries during matchplay; the shoulder/clavicle (52.8%) was the most injured locations; muscle/tendon (44.1%) and joint/ligament (42.1%) account for the majority of injuries. contact events (96.1%) were the main cause with an incidence of 22.4 per 1000 player days (95% ci: 18.4-26.3); in particular, during a tackle (46.7%). more than 60% of shoulder injuries resulted in minimal to mild (2-7 days) time-loss. conclusion: upper limb injuries accounted for 20.8% of all rugby injuries. the shoulder/clavicle is the most frequent region injured, muscle/tendon and joint/ligament were the common tissue type. most players sustained minimal to moderate severity during match-play and contact events were the main cause of upper limb injuries. injury surveillance data inform sports physicians and coaches about keeping players safe from injury, implementation of prevention strategies and optimal management of injuries will ensure the quickest and safest return to play following injury. mailto:tgaetsewe@hotmail.com f1: employee’s perceptions of leisure and retirement during the twelve months before retirement: a descriptive interpretive study in the kenneth kaunda district of the north-west province lulama mabala1, theron weilbach1 nwu phasrec1 26373769@nwu.ac.za background: the adjustment and adaptation process to retirement can be challenging and stressful for retirees. leisure can aid in the retirement adjustment process by providing the structure that is lost during retirement and provide benefits such as physical, cognitive, psychological, social, and selfdevelopmental benefits. planning for leisure is an essential component of planning for the retirement adjustment which is frequently overlooked by pre-retirees. a potential lack of adequate leisure planning before retirement can impact a person’s overall health during retirement. this study aims to describe and interpret perceptions of leisure and retirement during the 12 months before the retirement of blue and white-collar employees in the kenneth kaunda district. the dynamic theory of resources forms the theoretical foundation of the study. this approach provides a theoretical framework in which an understanding, anticipation, and examination of the relationships between people’s resources and their adaptation to retirement will be created. methodology: the participants will include at least 12 whiteand 12 blue-collar workers in the year before retirement. to gather data semi-structured face-to-face audio-recorded interviews will be conducted. data will be analysed by firstly transcribing the audio-recorded interviews, then a microscopic examination will be conducted to bring out the detailed, intensive, complexity of the data. once the microscopic examination is completed, the data will be analysed through a thematic process by using atlas.ti, which is a powerful workbench for qualitative data analysis. lastly, for quality purposes, a co-coder will be used for coding. results: n/a conclusion: to date, covid-19 posed a significant challenge. ultimately, it is expected that this study will provide valuable information to pre-retirees to make better-informed decisions to optimally adapt to retirement life. not only will it benefit the targeted study population but will also benefit organisations in the public and private sectors by guiding and showing them what should be included in a retirement plan. additionally, individuals who are proactively planning for their retirement may realise the importance of leisure before their actual retirement and make appropriate changes to their leisure behaviour. mailto:26373769@nwu.ac.za f2: patterns of participation in campus recreation sport and leisure boredom cornelia schreck1, nadine labuschagne1, cornelia m. schreck1, theron weilbach1 phasrec, north-west university1 cornelia.schreck@nwu.ac.za background: undergraduate students can experience leisure boredom when they are not exposed to campus recreation sport (crs), which in turn can lead to feeling unhappy, developing low selfconfidence, abusing substances, and in the end dropping out of university. more than one quarter (28.5%) of students in south africa (sa) drop out of university at the end of their first year after entering a four-year degree programme. a solution to students dropping out of university might be to increase student involvement and participation in campus recreation. the purpose was to determine the participation patterns in crs of undergraduate students at a south african university and to what degree they experience leisure boredom. methodology: a once-off cross-sectional design was used. the sample consisted of 581 students. an online survey consisting of various research instruments, including a demographic questionnaire, frequency and format of participation in recreational sport questionnaire, and items related to leisure boredom from the leisure experience battery for young adults by barnett (2005) was used. results: there were statistically significant differences between the gender groups’ frequencies of taking part in netball (p=0.010) and social dancing (p=0.044). there were statistically significant differences between all racial groups’ leisure boredom (p=0.000). medium to large practical significant differences was found between other/coloured (d=0.9), coloured/white (d=0.7) and other students and african students (d=0.6). statistically significant differences (p=0.017) for leisure boredom in the total sample regarding all three different accommodation types were found. conclusion: most students prefer to participate on their own or with their friends sharing the same interests, but not all on-campus activities cater to individual participation. this could be that students are more likely to choose activities that provide social opportunities with the social factor as the secondhighest-rated motivational factor for crs participation. only registered undergraduate students from one university participated in the survey, thus limiting the researcher with comparisons. mailto:cornelia.schreck@nwu.ac.za g1: cardiopulmonary exercise testing combined with cardiac rehabilitation exposing additional arrhythmias within aerobic metabolism, potentially due to oxidative stress – is this the missing link in unexplained cardiovascular deaths? johann els1 hpcsa1 history: “cardiac arrhythmia occurs frequently worldwide, and in severe cases can be fatal. mitochondria are the power plants of cardiomyocytes. in recent studies, mitochondria under certain stimuli produced excessive reactive oxygen species (ros), which affect the normal function of cardiomyocytes through ion channels and related proteins. mitochondrial oxidative stress (mos) plays a key role in diseases with multifactorial etiopathogenesis, such as arrhythmia; mos can lead to arrhythmias such as atrial fibrillation and ventricular tachycardia.” – liu et al, 2022 physical findings: additional arrhythmias and premature ventricular contractions are exposed within the aerobic metabolism through ecg monitoring, which the anaerobic stress ecg cannot expose the aerobic ecg can potentially clarify unexplained cardiovascular disease. literature suggests that “electrical instability and electrical remodelling underlying the arrhythmia may result from a cellular energy deficit and oxidative stress, which are caused by mitochondrial dysfunction.” clinical and sub-clinical data are provided. these observations can only be exposed through an in-depth analysis of various physiological variables following a resting metabolic rate assessment and cardiopulmonary exercise testing. individuals that were monitored for an extended period showed additional clinical pathology (that would not have been exposed previously) during physical exercise. this potentially showed weakened physiological systems that could expose oxidative stress, which might play an underlying role in unexplained pathology of various chronic diseases. differential diagnosis / hypothesis: the clinical importance of ideal oxygen supply and uptake on a cellular level (during exercise) is not yet fully understood. once the weakest cell is exposed to the optimal oxygen supply or uptake, the true functional status of the cell seems to produce oxidative stress (due to mitochondrial dysfunction), causing the true underlying clinical status to be exposed, i.e., electrical instability within the heart. the sinus rhythm appears to be normal, leading to a hypothesis that the clinical pathology present is within the mitochondria of the heart in need of rehabilitation. exercise within the aerobic metabolism releases oxidative stress, preventing further damage to various intracellular substances that affect normal functioning of the body, and cause of disease. test and results: subjects underwent the following battery of tests: components of screening and risk profiling on the medicise patient management system consist of: 1. completing the par-q questionnaire 2. informed consent. 3. exercise participation 4. known diagnoses (cardiovascular/metabolic/renal) 5. signs and symptoms suggestive of cardiovascular/metabolic/renal disease 6. risk factors 7. medical history cardiometabolic assessments include: https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/heart-arrhythmia https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/reactive-oxygen-metabolite https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/atrial-fibrillation https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/atrial-fibrillation https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/heart-ventricle-tachycardia (a) resting metabolic rate assessment (b) spirometry (c) cardiopulmonary exercise test the sample consisted of 14 men and women (after referral for exercise training with non-communicable diseases); age distribution: 17 – 81 years, both male and female. risk profiling was done through screening and pre-exercise evaluation protocol as per guidelines by the american college of sports medicine. data from a resting metabolic rate towards maximal exertion were gathered using metalyzer®3b and metasoft®studio software (analysing 86 physiological variables/calculations) from cortex biophysik gmbh and custo cardio 300 (analysing comprehensive ecg variables) from custo med gmbh. a physiological analysis was followed to identify the ideal exercise intensity according to the optimal oxygen supply and uptake zone. the results showed the clinical importance of cardiopulmonary exercise testing in the sample group. internationally “cardiopulmonary exercise testing applications in cardiology have grown impressively to include all forms of exercise intolerance.” a leading cardiology practice in the western cape provided the following interpretation of the 14 case studies "from the data that you showed my biggest clinical concern is that some of your patients may have a very high load of ventricular ectopics and by implication, some of your data points even suggest that certain patients may be having runs of ventricular tachycardias-which is very dangerous if true. there are also suggestions in your data that there may be other arrhythmias which are elicited during exercise such as focal atrial tachycardias etc." final/working diagnosis: each individual either has a functional or clinical physiological weakness within integrative physiology. identifying the physiological cause of exercise intolerance is the essence of understanding the clinical problem. once this weakness is exposed to the optimal oxygen supply or uptake quantity within the integrative physiology, the human body will be provided with the chance to initiate the healing process through oxygen exposure. treatment and outcomes: all subjects participated in exercise using custo med diagnostic standard cardiac rehabilitation software to monitor cardiovascular response during exercise with ecg monitoring. subjects were monitored for a minimum of three (3) and a maximum of 259 exercise sessions (minimum 20 minutes at a time) while ecg monitoring provided clear information of the cardiovascular response during exercise. ecg monitoring allowed for a comprehensive, and correct profile of arrhythmia and premature ventricular contractions during exercise within the aerobic metabolism. individuals that were monitored for an extended period showed clinical pathology during exercise for clinical interpretation during physical exercise. this led to a better understanding of the specific physiological systems that needed prolonged exposure to optimal oxygen. important to note that most subjects could reduce cardiac arrhythmias while increasing the first anaerobic threshold and peak oxygen uptake significantly through participation in cardiac rehabilitation with ecg monitoring. clinical case study: 78-year-old active male with the following medical history:  coronary artery disease  concomitant respiratory disease  covid-19 infection (march 2020)  hypertension  diabetes  gout results of 259 exercise sessions over a period of 16 months with ecg monitoring: first anaerobic threshold before 259 exercise sessions first anaerobic threshold after 259 exercise sessions 1.04 l 1.62 l peak oxygen uptake before 259 exercise sessions peak oxygen uptake after 259 exercise sessions 1.44 l 2.21 l g2: bertolotti's syndrome: overlooked, under-diagnosed? kobus slabber1 sasma1 history: a comparative presentation about two cases of bartolotti's syndrome one treated conservatively and one that needed surgical intervention. case a: 24 y/o female with two-month history of gluteal/lower back pain, spreading down her leg when sitting and sprinting. unresponsive to physiotherapy and anti-inflammatory treatments. case b: 45 y/o female with lower back pain, claudication type pain spasms that did not improve on physiotherapy and anti-inflammatory treatments. physical findings: case a: tender with slightly palpable protrusion over the piriformis area. normal general and neurological evaluation. case b: tender over l-spine, no other musculoskeletal abnormalities. normal general and neurological evaluation. differential diagnosis / hypothesis: case a: sciatica, piriformis syndrome, si-joint/facet arthropathy, lumbar radiculopathy annular tear/discus protrusion. case b: lumbar arthropathy/radiculopathy foraminal stenosis/discus protrusion. test and results: case a: ultrasound (hamstring calcification), x-rays (sacralisation), ct-scan & mri to be done under consent for academic reasons of submission accepted. case b: x-rays (sacralisation), ct-scan (bilateral sacralization), mri (left l5 nerve compression). final/working diagnosis: case a: bertolotti's syndrome with right-sided l5 radiculopathy. case b: bertolotti's syndrome with left-sided l5 radiculopathy. treatment and outcomes: case a: cortisone and local infiltration pain-free. case b: cortisone and local infiltration unsuccessful. anterior sacrolumbar decompression pain-free. h1: a comparison of the risk profile for developing illness-related medical encounters in halfand ultramarathon runners dc baker1, 2, ps wood1, 2, tcds camacho1, mp schwellnus2, 3, 4, s swanevelder5, jordaan e6 division of biokinetics and sports science, department of physiology, faculty of health sciences, university of pretoria, south africa1, sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa2, international olympic committee (ioc) research centre, south africa3, emeritus professor, faculty of health sciences, university of cape town, south africa4, biostatistics unit, south african medical research council5, biostatistics unit, south african medical research council; statistics and population studies department, university of the western cape6 dean.chris.baker@gmail.com background: research comparing risk profiles for medical encounters in race entrants at distance running events is limited. the aim of this study was to determine and compare the risk profile for developing illness-related medical encounters in half-marathon compared to ultramarathon runners. methodology: online pre-race medical screening questionnaire data from 76654 consenting race entrants (71.8% of all entrants) over four years of two ocean marathon (2012-2015) were analysed, using a prospective cross-sectional observational study design. study participants were classified into four risk categories (‘very high risk’, ‘high risk’, ‘intermediate risk’ and ‘low risk’) based on the history of the following: existing cardiovascular disease (cvd), history of any symptoms of cvd, or any risk factor for cvd, disease in other organ systems, medication use and history of collapse in half-marathon and ultramarathon. we report the prevalence (%; 95%ci) in each risk category for halfand ultra-marathon entrants. results: most entrants in the half-marathon race were classified in the “low” risk category (43.20%; 95% ci 42.7-43.7), followed by “intermediate” (41%; 95% ci 40.5-41.6) and “high” (12.6%; 95% ci 12.2-13.0) risk categories. the majority of entrants in the ultramarathon were classified in the “intermediate” (51.90%; 95% ci 51.2-52.6) risk category, followed by “low” (36.20%; 95% ci 35.5-36.9) and “high” (9.10%; 95% ci 8.7-9.4) risk categories. additional findings include higher prevalence of an existing cvd in half-marathon runners (1.66%; ci 1.53-1.81) compared to ultramarathon runners (1.36%; 95% ci 1.211.54), and a higher prevalence of risk factors for cvd in half-marathon runners (12.46%; ci 12.11-12.81) compared to ultramarathon runners (9.27%; 95% ci 8.89-9.67). conclusion: half-marathon runners had a higher prevalence of existing cvd and cvd risk factors than ultramarathon runners. however, more than half of the ultramarathon runners reported (a) existing chronic disease in other organs, (b) use of prescription medication, (c) use of anti-inflammatory drugs, and (d) history of collapse during exercise. mailto:dean.chris.baker@gmail.com h2: eye pathologies in para athletes in the winter settings: an analysis of the sochi 2014 and pyeongchang 2018 paralympic winter games lovemore kunorozva1, ali ganai1, phoebe runciman1, wayne derman1 institute of sport and exercise medicine (isem), division of orthopaedic surgery, faculty of medicine and health sciences, stellenbosch university, stellenbosch, south africa1 kvnorozwa@gmail.com background: eye pathologies have a negative effect on a para athlete’s performance and well-being. an in-depth description of the nature and presentation of these eye pathologies could assist in developing prevention strategies for such pathologies in future. the aim of this study was to describe the nature of eye pathologies presenting in para athletes during the sochi 2014 and pyeongchang 2018 paralympic winter games. methodology: this study investigated eye pathologies in para athletes using the web-based injury and illness surveillance (web-iiss) tool during the 2014 sochi and 2018 pyeongchang paralympic winter games. descriptive data were obtained and analysed from a de-linked database containing para athlete information on eye illnesses and injuries from the two winter paralympic games. results: ice sledge hockey (30.3%), nordic (19.2%) and alpine (18.4%) skiing, accounted for the sports with most of the eye pathologies reported during the two winter games. furthermore, the majority of eye pathologies were reported in athletes with an amputation or lower limb deficiency (66.9%), visual impairment (18.4%) and those with a spinal injury (11.9%). conclusion: male para athletes, mostly taking part in ice sledge hockey and those with lower limb deficiency or visual impairment suffer more eye pathologies during winter paralympic games. furthermore, environmental eye illnesses and allergic conjunctivitis account for just below half of all eye illnesses and were associated with snow glare/dry eye and pre-existing allergy or asthma conditions, respectively. the findings from this study may aid the development of eye pathology prevention strategies in winter sport settings. mailto:kvnorozwa@gmail.com h3: eye pathologies in para athletes in the winter settinga systematic review lovemore kunorozva1, ali ganai1, phoebe runciman1, wayne derman1 institute of sport and exercise medicine (isem), division of orthopaedic surgery, faculty of medicine and health sciences, stellenbosch university, stellenbosch, south africa1 kvnorozwa@gmail.com background: eye illnesses can be detrimental to athletes’ performance and well-being. these ocular illnesses may be an inherent finding in athletes with visual impairment, however acute eye illness might also be present in athletes with other impairments. yet, these illnesses have not been explored in paraathletes. the aim of this systematic review was to describe the epidemiology of eye pathology presenting in para athletes in both winter and summer sports settings. methodology: a comprehensive literature search of eye pathologies presenting in para athletes was conducted employing pubmed, ebscohost and web of science databases up to june 2021. each of the articles was independently reviewed for relevance and inclusionary criteria, with nine studies meeting these criteria. results: overall, the quality of the included studies was excellent. illnesses in the eye and adnexa were more prevalent in winter (ir: 1.6 2.2/1000 athlete days) compared to summer (ir: 0.3-0.5/1000 athlete days) sports settings. eye pathologies were reported in athletes with limb deficiencies (22.4%), spinal cord injury (20.3%), visual impairment (15.1%) and central neurology injury (14.8 conclusion: the findings of this review indicate that: 1) eye pathology in para athletes is an understudied area; 2) eye pathology is present in athletes other than those with visual impairment. there is a need for further research on eye pathology, particularly in winter sports settings in order to understand the types and nature of eye pathologies that affect para athletes during competition and training settings mailto:kvnorozwa@gmail.com h4: an analysis of the partial feasibility of a novel cardiac exercise rehabilitation programme for patients suffering from cardiovascular disease ms tayla ross1, dr jacolene kroff1, dr elizma atterbury1 university of cape town1 tay.ross100@gmail.com background: south africans are facing a growing problem of cardiovascular disease (cvd), which has major implications for healthcare services and has placed increasing strain on the struggling south african healthcare system. cost-effective prevention and management measures are needed to slow down the growing cvd epidemic and relieve strain on healthcare systems. the need exists for more evidence to demonstrate that cardiac exercise rehabilitation programmes (crps) can significantly reduce readmissions, mortality, comorbidities, and improve the quality of life throughout the country. the aims of this study were to determine the partial feasibility of a novel crp in a south african public hospital setting to provide optimal and sustainable healthcare to cvd patients. methodology: partial feasibility was assessed by evaluating the recruitment potential and sample population characteristics of the target population, through the retrospective analysis of the victoria hospital vimri database, and by evaluating the test-retest reliability of the prospective protocol testing and monitoring measures through 3 different methods. results: 209 participants were assessed according to inclusion and exclusion criteria. 109 (52.2%) were considered ineligible for a crp, whereas 100 individuals (47.8%) were considered eligible. there were no significant differences between the populations in terms of anthropometry, however, there were significant differences for 4 comorbidities and 2 medications. 22 outcome measures were assessed for reliability, 5 were classed as having “poor” reliability, 9 as “moderate”, 3 as “good” and 5 as “excellent’. 18 measures had a lower than small effect size (d<0.2), indicating near identical repeated measures and excellent test-retest reliability. the remaining 8 had small effect sizes between 0.2-0.5. conclusion: it is expected that 33 patients (100 participants/3 months) will be eligible for the crp every month, which is nearly triple the expected intake, exceeds prospective resource and staff capacities and is greater than what can currently be accommodated. we recommend that the number of resources and trained staff be increased before crp implementation. the majority of the monitoring tools assessed had acceptable test-retest reliability. however, the methods used to measure blood pressure, oxygen saturation and rate of perceived exertion were questionable. we recommend that alternative devices are utilised for these variables. mailto:tay.ross100@gmail.com h5: a scoping review examining physical activity interventions for the management of hypertension mandisa simamane1 university of the witwatersrand1 a0047345@wits.ac.za background: as populations age, adopt more sedentary lifestyles, and increase their body weight, the prevalence of hypertension worldwide is continuing to rise. one of the main non-pharmacological strategies for prevention, control, and treatment of hypertension and its future complications is physical activity. aim: the main aim of the study was to identify the type of physical activity intervention that can assist hypertensive patients in managing hypertension. a scoping review was used as a drive toward evidence-based practices and as a technique to map relevant literature and the types of evidence available with regards to management of hypertension using physical activity. methodology: a systematic computer-based search was undertaken through the university of the witwatersrand/ libguides/ electronic resources/ database a-z. search words were as our inclusion criteria of (1) hypertension/ high blood pressure, (2) exercise/ physical activity, (3) intervention/ training intervals, (4) frequency, intensity, time & type, (5) for the period of 2009 to 2020. results: the results led to 32 randomised controlled/ experimental studies which fulfilled the criteria required and included: what study design was used, where was the study located, what was the sample size, and what sex and race/ ethnicity. a 16-week lifestyle intervention significantly improved cardiovascular risk factors in all groups, and pharmacological therapy was largely reduced or removed completely. conclusion: concluding, it was found that different exercise modalities elicit very different changes in blood pressure variability while they induce similar reductions in blood pressure values. caution and good judgment should be used when prescribing more rigorous exercise for those with high blood pressure. the data showed that elderly hypertensive individuals undergoing pharmacological treatment may benefit from practising resistance exercise and that their pressure will probably not go up as a result. these data suggest that antihypertensive treatment can also reduce the concern that physical exercise can produce an extreme and acute hypertension response in hypertension subjects. the use of aerobic exercise is a gold standard exercise to reduce blood pressure. even for patients who have wellcontrolled bp, aerobic exercise performed alone is an effective strategy to reduce bp during the hours after the cessation of exercise. mailto:a0047345@wits.ac.za i1: motivation for exercise and the effects of exercise participation on mental health during the covid-19 lockdown in south africa courtenay m. davis1, heather morris-eyton1 department of sport and movement studies, university of johannesburg1 courtenaymunro@gmail.com background: the coronavirus (covid-19) pandemic posed a significant threat to the physical and mental health of the south african population. it changed the way in which individuals were able to exercise in order to maintain physical fitness during the various levels of government enforced lockdown restrictions. the purpose of this study was to draw a comparison of the levels of motivation between virtual and non-virtual workouts which occurred during the covid-19 lockdown in south africa. methodology: an internet-based survey examined in part exercise motivation between virtual and nonvirtual workouts during the lockdown. this was an adapted version of the srq-e as it explored the reasons for exercising and whether participants' motivation for exercising was intrinsic or extrinsic. participants (n=120) were residing in south africa and had to have completed at least one virtual and non-virtual workout during the covid-19 lockdown (march 2020 – february 2021). a descriptive and comparative analysis was conducted to gain insight into the comparison between the motivation of the different workout regimens, and why participants preferred their workout regimen of choice. results: during the lockdown, virtual workouts were enjoyed most often (52%). this was primarily due to the social setting (32%) where participants felt they were still engaging in exercise with others, and the interaction with their instructor (32%). participants who preferred non-virtual home-based workouts reported that they could work out at a time convenient to them (68%) and at their own pace and fitness level. participants who favoured non-virtual workouts were intrinsically motivated to participate in exercise programmes (m=5,92, sd=0,91,) when compared to those who preferred virtual workouts (m=5,48, sd= 1,10). men (m=5,99, sd= 0,90) were more intrinsically motivated to engage in workouts during lockdown than women (m=5,52, sd= 1,07). the participation in physical activity during the covid19 lockdown played a role in boosting mental health as it positively increased 92% of the participants' mood conclusion: physical activity had a positive effect on mental health during the lockdown. participating in virtual workouts was the preferred mode of exercise, however, those who partook in non-virtual workouts showed higher levels of intrinsic motivation. mailto:courtenaymunro@gmail.com i2: physiological risk profiles of asymptomatic males performing the salaah (islamic prayer) as a low-intensity physical activity abdul hamid jalal1, habib noorbhai1 department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa1 hamidj@uj.ac.za background: the islamic prayer (salaah) has been found to be a type of low-to-moderate intensity aerobic exercise and has physiological and psychological benefits for one’s health. the aim of this study was to investigate and determine the physiological risk profiles using selected clinical measurement tools. methodology: using a cross-sectional research design, an intervention study of selected morphological, cardiovascular and neuromuscular variables on a sample of asymptomatic males (n = 20), aged 21 – 40 years, was conducted. resting heart rate (rhr), resting systolic blood pressure (sbp), resting diastolic blood pressure (dbp), body mass index (bmi) and percentage body fat (bf%) were measured prior to a salaah simulation activity. electromyography (emg) measurements were performed on the vastus medialis oblique (vmo) for a single maximum voluntary contraction (mvc) along with two movement transitions of the salaah. bilateral manual muscle strength testing (mmt) using a myometer was conducted on the quadriceps femoris muscle group. using spss (version 27, ibm), descriptive and inferential statistical analyses (including pearson’s correlation coefficient to explore links between all variables in the study) were conducted. the level of significance for these correlations was set at p<0.05. results: negative correlations were found between rhr and mvc average (r = -0.03; p = 0.91) ; post salaah sbp and mvc average (r = 0.19; p = 0.42) ; post salaah dbp and the mvc average (r = -0.41; p = 0.08). positive correlations were found between the mvc average with right (r = 0.14; p = 0.56) and left (r = 0.18; p = 0.44) quadriceps femoris mmt and between bmi and bf% (r = 0.69; p = 0.00). rhr (r = 0.26; p = 0.27), resting sbp (r = 0.49; p = 0.03), post salaah sbp (r = 0.27; p = 0.26) and post salaah dbp (r = 0.36; p = 0.12) were positively correlated with bmi. conclusion: this study demonstrated that a sample of asymptomatic males who perform the daily salaah were within reasonably healthy norms. the study also demonstrated that a physiological benefit can exist by the salaah as a form of light-intensity aerobic activity in clinical exercise rehabilitation. mailto:hamidj@uj.ac.za i3: barriers to participation in sport among urban adolescents attending an international school in cape town, south africa robyn klaasen1, maya van gent1, habib noorbhai2 university of fort hare1, university of johannesburg2 robynklaasen@outlook.com background: the global decline in participation in physical activity and sport by adolescents remains a cause for concern. few of the many studies that have been conducted have concerned south africa, specifically outside of a rural or disadvantaged context. the purpose of this study was to identify the principal barriers to participation in sport and make a comparative appraisal of their influence on male and female adolescents at an international school in cape town, south africa. methodology: the barriers to sport participation questionnaire (bspq) was completed by 107 voluntary respondents. the data was validated by a kaiser-meyer-olkin (kmo) value of 0.808 and a chi-square value of 2403.664 (p = 0.000; df = 820). results: the results revealed seven principal barriers, of which fear of academic failure, environmental constraints, and lack of interest were the most influential. it was also established that the barriers exerted the most influence on female respondents and on those respondents who either did not participate in sport or were from households whose other members did not do so. conclusion: the findings underscored the need for education and exposure to the sport and the need to promote the sport in response to specific disparities, even if doing so entails the implementation of segregated programmes. mailto:robynklaasen@outlook.com i4: the relationship between barriers to participation in sport for adolescent learners and the grade (scholastic year) in which they are enrolled: a case study in an international school in cape town, south africa robyn klaasen1, maya van gent1, habib noorbhai2 university of fort hare1, university of johannesburg2 robynklaasen@outlook.com background: participation in sport among adolescents continues to decline at an alarming rate throughout the world. while several studies have been conducted to identify barriers to participation, limited research, particularly in south africa, has been conducted to detect correlations between specific barriers and other variables. the purpose of this study was to identify barriers to participation in sport among urban adolescents and determine correlations between individual barriers and grade (scholastic year) in an international school in cape town, south africa. methodology: the barriers to sport participation questionnaire (bspq) was completed by 107 learners at the school. the data was validated by a kaiser-meyer-olkin (kmo) value of 0.808 and a chi-square value of 2403.664 (p = 0.000; df = 820). results: seven principal barriers were identified, of which fear of academic failure, environmental constraints, and lack of interest were the most influential. regression analysis revealed that the fear of academic failure, health and injury-related concerns, and no relevance or priority barriers were the most significant, particularly among grade 7 and grade 9 learners. conclusion: consequently, it appears probable that barriers to participation in sport could be specific to particular school year and that interventions need to be specific, appropriate, well-timed, and effectively implemented during the middle school years of grades 6 to 8, to encourage sustained engagement with sport and mitigate the global decline. mailto:robynklaasen@outlook.com j1: relationships between ground reaction force, isokinetic knee strength, and the incidence of lower extremity injuries in university-level netball players henriette hammill1, lenthea kamffer2, mark kramer2, yolandi willemse3 physical activity, sport, and recreation (phasrec) research focus area, north-west university, potchefstroom, south africa1, center for health and human performance, north-west university, potchefstroom, south africa3 12782211@nwu.ac.za background: given the physical demands (e.g., agility), outcomes (e.g., potential injury), and increasing competitiveness of netball, the monitoring of certain performance characteristics has become increasingly important in order to better understand the injury risk factors at play. the repeated highimpact loading on the lower extremity joints increases the risk of injury. knee strength provided during the co-contraction of the hamstringand quadriceps muscle groups give dynamic stabilization which is particularly important during landing. the aim of this study is to perform a literature review on the incidence of lower extremity injuries in netball players. methodology: a typical prisma literature surveillance is applied: an electronic literature search was conducted using the key search terms “netball”, “ground reaction force”, “isokinetic knee strength”, “lower extremity injuries”, “landing kinetics”, “time to stabilisation”, “force plate”, “dynamometer”, “eccentric”, “injury mechanics”. peer-reviewed, english-written research articles were included in this literature review. results: there is a high incidence (>50%) of lower extremity injuries in netball players. conclusion: the fact that netball is a fast-paced, multi-directional movement sport with many jumps, leaps and landings, the resultant grf is a significant risk factor to consider when investigating lower extremity injuries. knee muscular strength contributes to the stability of the lower extremities during landing from a jump and along with grf, isokinetic knee strength plays a vital role when investigating lower extremity injuries. this literature review regarding the relationship between grf, isokinetic knee strength and the incidence of lower extremity injuries in university-level netball players will aid valuable information towards conditioning protocols, training loads, rehabilitationand prehabilitation protocols, lowering the risk for injuries, as well as re-occurrence of previous injuries and optimising performance. mailto:12782211@nwu.ac.za j2: kinematic gait comparison between back-carried-, and non-back-carried setswanaspeaking children mariaan van aswegen1, stanislaw h czyz1, 2, 3, sarah j. moss1 phasrec, north-west university, south africa1, faculty of physical education and sport, wroclaw university of health and sport sciences, wrocław, poland2, faculty of sport studies, masaryk university, brno, czech republic3 20383800@nwu.ac.za background: setswana children are back-carried by their mother, often deep into their toddler years. static lower limb investigations of setswana children rendered differences in the tibiofemoraland tibial torsion angles between back-carried and non-back-carried children. this leads to the question of whether dynamic differences during gait would be noticed between back-carried and non-back-carried setswana-speaking children. this study aimed to compare the angles observed at the hip, knee and ankle in the frontal, sagittal and transverse planes, during kinematic gait analyses of back-carriedand non-back-carried children. methodology: twelve non-back-carried(mean age=8.00±0.95 years) and 14 back-carried (mean age=8.01±0.73 years) children were selected from a larger (n=691) study. analysis of hip, knee and ankle joint kinematics, using the qualisys track manager software, were performed in the three cardinal planes, at heel-strike-, mid-stance-, and toe-off gait phases. the angles (outcome variables) were compared with the dependent groups, back-carrying and non-back-carrying, age and sex, using manova. results: a two-way manova was used to evaluate the joint angles observed for back-carried versus non-back-carried children and their respective ages. back-carrying was not significant, while age was a significant predictor for joint angles, f(1, 17)=209.246, p=0.054, η2=1 and f(1, 17)=8.331, p=0.026, η2=0.986; respectively. the interaction between back-carrying and age was not significant f(4, 34)=1.210, p=0.482, η2=0.911. some individual significant differences were observed at the knee and ankle joint. a comparison of back-carrying with the knee in the sagittal plane, during the mid-stance gait phase, was significant (p=0.017). comparisons of age with the ankle; was significant in both the sagittal plane, during heel strike (p=0.016), and in the frontal plane, during mid-stance (p=0.042). a comparison between back-carrying and age with the ankle in the sagittal plane, during the heel strike gait phase (p=0.027), was significant. conclusion: most setswana-speaking children are back-carried for the bulk of their toddler years (between 2 to 5 years of age). relationships between back-carrying and static lower limb measures were previously found but differences were within normal ranges (for example genu valgum), yet none of these relationships translated to the kinematic analysis. thus, we argue that back-carrying does not pose an orthopedic risk to children. mailto:20383800@nwu.ac.za j3: effect of 6 weeks functional intervention program on fms score and the relationship with the single leg hop test in female netball players dimitrije kovac1, ranel venter1, zarko krkeljas2 department of sports science, stellenbosch university1, duke kunshan university2 dmtrjkovac888@gmail.com background: functional movement screen (fms®) is currently one of the most widely used preparticipation testing protocols, even though the research studies have reported equivocal results across sports disciplines. nonetheless, in sports where non-contact lower limb injuries are prevalent as in netball, fms® may be a valuable tool used alongside other clinical assessment protocols to provide adequate feedback to sport practitioners as the return-to-sport guidelines after an athletic injury. willingenburg and hewett (2017) have also indicated that other functional tests such as different forms of the hop for distance test, maybe a more practical and viable addition or even a substitute to fms®. methodology: convenient sample of 40 elite female university players, randomly divided into control and the intervention group, volunteered for the study. of the 40 players who were initially tested, nine were excluded from the study either due to withdrawal from the team, or minor injuries. the fms® score and single leg hop test were measured before and after the six-week training cycle. results: after a six-week intervention there was a significant (p < 0.001) increase in fms® score for the experimental group, while the control group score remained unchanged. relative to the relationship between fms® and hop test, the results show a moderately significant correlation (r=0.48, p < 0.001) between the fms® total score and single-leg hop test when performed with the dominant leg. testing on the non-dominant leg also indicated a potentially significant relationship, although statistically not significant (r = 0.34, p=0.06). similarly, the correlation after intervention remained moderately significant (r=0.36, p<0.05). athletes with higher fms® scores had longer jump distances in the slh test (0.48) which coincides with the results of the study conducted by willigenburg and hewett (2017) who reported (r= 0.38 0.56). conclusion: the fms® score in female netball players could be improved by a standardized corrective exercise program. findings of the current study showed positive correlations between the total fms® score and slh test, as well as the hs and slh when performed with the dominant leg. however, there was no significant improvement in slh distance after the intervention. mailto:dmtrjkovac888@gmail.com j4: morphological characteristics and their relationships to performance in male cross-country runners clinton deon swanepoel1, dumisane hlaselo1, adrian lombard1, andrew green1 department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa1 cswanepoel@uj.ac.za background: cross-country running is characterized as high-intensity intermittent and continuously running over surfaces like grass, mud and dirt. morphological testing relates to tests of the divisions of biology that deals with the systems of living organisms and the connections amongst their structures. morphological characteristics is used to describe the body shape and proportion of individual bodies. physiological tests establish how the bodily parts function within the living organism. physiological characteristics can determine the factors that affect performance and the ability to recover after maximum effort. the aim of this research was to determine the relationship between morphological and physiological characteristics of senior male cross-country athletes in gauteng province, south africa. methodology: forty competitive male cross-country athletes participated in this study. parameters tested included stature, body weight, seven skinfolds, body fat percentage and lean body mass. the maximal oxygen consumption, running economy and two ventilatory thresholds (vt1 and vt2) were calculated using online assessments. data were analysed using descriptive statistics (spss, v.21). a correlation matrix (pearson correlation) was calculated between physiological and morphological parameters. results: the results of this study indicated mean values of body weight (63.05 kg), body fat percentage (8.04 %). the mean values for maximum oxygen consumption (vo2max) (63.50 mlo2.kg˗1.min-1). the vt1 and vt2 were calculated and at the intensities corresponding to the last point before a first nonlinear increase in both vt1 and vt2. the results show a strong positive correlation between stature and mass (r = 0.652, p = 0.01) as well as a weak correlation between bf% and stature (r = 0.382, p = 0.05). there was a positive correlation between bf% and mass (r = 0.575, p = 0.01). there was a weak negative correlation between vo2 and mass (r = -0.368, p = 0.05). the v ̇o_2max and vt values did not relate to any physical parameters of this sample. conclusion: these characteristics are generally associated with cross-country runners. this research will serve as a basis for future studies and will provide information on senior male cross-country athletes, which can be referred to by coaches and sports scientists who train athletes during the competition preparation phase. mailto:cswanepoel@uj.ac.za k1: psychological factors affecting physically disabled athletes in south africa koketjo tsebe1 unisa, softball south africa and sascoc1 tsebekb@unisa.ac.za background: the number of athletes with disabilities participating in organized sports and the popularity of the paralympic games is steadily increasing around the world. many athletes with disabilities agreed that sport is an important tools to affirm their competence and worth. the aim of this study is to evaluate the self-efficacy, athletic identity and motivation of athletes with a physical disability. methodology: the study will adopt a quantitative research approach. it will be an evaluative research design to allow assessing psychological variables under study. a purposive sample of physically disabled athletes from different sporting codes will be invited via their federations to participate in the study. the researcher will select participants based on the pre-defined characteristic, which is gender (male) and age (18 years and above). it is expected that 50 participants (25 females, 25 men) from different sporting codes will participate in the study. research data will be collected using biographical information and three psychometric tests that measure the psychological variables under study. the biographical section will include variables such as gender, age, sporting code, level of sport participation, disability (congenital, acquired) and type of disability (e.g., spinal cord injury). the three psychometric tests to measure variables under study are: rosenberg self-esteem scale (rse), athletic identity measurement scale (aims) and sport motivation scale (sms). the questionnaire will be available through surveymonkey which is an electronic platform for research. data will be analysed using spss version 25 statistical package. the study will abide by the basic ethical standards of social research. results: it can be predicted that physically disabled athletes will report low levels of self-efficacy; physically disabled athletes will identify strongly with their athletic roles, physically disabled athletes will score higher on the sport motivation and there will be a significant relationship between self-efficacy, athletic identity and motivation conclusion: physically disabled persons are challenged to cope with a wide range of stressors in maintaining meaningful lives. the adjustment depends, in part, on psychological and social factors that promote effective coping with old and new demands. mailto:tsebekb@unisa.ac.za k2: the perceptions of primary caregivers on the social skills and recreational activities of children aged 10-12 years with down syndrome cara m. myburgh1, cindy kriel1, yolanda stevens1 fasrek nwu1 cindy.kriel@nwu.ac.za background: children with down syndrome (ds) are known to have fewer responses to social initiations and interactions with peers and other people, which results in difficulties with social relationships. children with ds are described as being “very sociable” and this is also evident from previous research, where parents of children with ds have different perceptions and views, as some are concerned about their child’s social life and others see them as sociable individuals. yet, leisure and recreation have a social value which purposefully serve today’s society and the direction of an individual’s life. methodology: this study aimed to determine the primary caregivers’ perceptions of the social skills and recreational activities of their 10to 12-year-old children with ds. semi-structured interviews were conducted with 13 primary caregivers, whereafter data was analysed through content analysis. results: two major categories were identified from the data, each with various themes and sub-themes. the primary caregivers perceived their children to have relative strengths in making friends, as well as non-verbal social skills such as physical proximity and keeping eye contact during a conversation, compared to verbal communication skills in opening and ending a conversation and setting boundaries for self-disclosure. with regard to recreational activities, the primary caregivers mentioned that, at home, their children mainly participate in sports followed by music, drama, fine arts and intellectual/ literary activities. conclusion: the children’s behaviour in the majority of social skills was however dependant on various situations, where a certain social skill was sometimes seen as a strength and other times they seem to struggle with the same skill. one of the major areas which primary caregivers identified as barriers to social interaction was their difficulty in speech. most of children with ds have also never experienced exclusion from participating in leisure and recreation activities. mailto:cindy.kriel@nwu.ac.za k3: effect of limitless you peak performance program on the brain, health and skillrelated fitness of netball players peet du toit1, mr ralph hwenjere1, ms rebekah janse van rensburg1, dr janette bester1 department of physiology, school of medicine, faculty of health science, university of pretoria1 peet.dutoit@up.ac.za background: netball players have to constantly be alert to make quick, precise decisions. brain fitness is as important as physical fitness in the sport, and an alignment of both would make players particularly competitive compared to the rest. the limitless you peak performance program (lyppp) is a highly developed assessment and intervention program, designed specifically to enhance the following three core areas: reducing overall stress, improving cognitive intelligence and the enhancement of overall performance. this program also serves to strengthen the brain-body balance by assessing and training the three core areas of performance, namely, brain performance, health-related fitness and skill-related fitness. methodology: the study was an interventional pre-post experimental design. the overall current wellness of 30 netball players was evaluated at the start of the study. the lyppp assessments included brain performance, health-related fitness and skill-related fitness assessments. following the tests, the participants then participated in the lypp intervention program. fifteen intervention sessions were conducted, with each aiming to enhance the brain, health and skill-related fitness of the participant. on completion of the interventions, a post-test was conducted to assess if the intervention employed benefited the performance of the players. results: significant changes were seen in brain fitness and the players’ overall brain scores. the mean difference in neuro-agility (%) subsequent to the lyppp intervention was 11.5 ± 13.031 with p = 0.01. no particular change was observed in visual acuity, visualisation, vergence and sequencing after the interventions. the mean letters read for focussing increased by an average of 44 letters read across the team, which was a significant improvement. tracking and ice-cube tests also showed significant improvement. conclusion: the lyppp improved brain, health and skill-related fitness in the players. this intervention contributed to the netball team winning the south african tournament. therefore, due to the positive impact of the lyppp training, there is potential for this method of training to become more commonly used for the benefit of sports team performance and outcomes. mailto:peet.dutoit@up.ac.za k4: the effects of the covid-19 lockdown on physical, mental, and emotional parameters among regular sports persons habib noorbhai1, amaarah khan1, ammaarah patel1 faculty of health sciences, university of johannesburg1 habibn@uj.ac.za background: the covid-19 pandemic rapidly spread throughout the world which resulted in a lockdown that was implemented in south africa on the 26th of march 2020. as a result, it affected the lives of many people, including sportspersons. the purpose of this study was to understand the physical, mental and emotional adaptations that regular sportspersons had to conduct under lockdown regulations. methodology: this was a mixed-methods study in which analytical research methods were employed. a survey (adapted from a fitness and wellness questionnaire) composed on google forms was used for this study. this questionnaire included questions about the participants’ (n = 100) physical and mental well-being throughout the lockdown period. questionnaires were distributed via an online link over social platforms (whatsapp, instagram, twitter, and via email). these answers were exported through an automatically generated microsoft excel spreadsheet which was then retrieved by the researchers for analysis. a thematic analysis was also used to identify common themes and stated results of the data. the normality tests used were the kolmogorov-smirnov test as well as the shapiro-wilk test for statistical analysis, using spss (version 27, ibm). the level of significance was set at p<0.05. results: participants partook in cardiovascular training, flexibility training, strength training, and bodybuilding exercises (pre-lockdown). during the lockdown, more than 74% of the participants had adequate training space, equipment and time to perform physical activity but more than 43% of these participants experienced a decrease in flexibility, muscle mass, and muscle strength. exercise was used as a form of stress relief by 77.1% of participants throughout the lockdown. however, participants who used exercise as a form of stress relief continued to experience an increase in stress throughout the lockdown period. conclusion: the outcomes of this study showed that the covid-19 lockdown had an adverse effect on the overall health and well-being of most sportspersons. other outcomes included the effects of inactivity, diet and sleep (deprivation) on the body. the extent of such effects could have been further explored by the researchers. due to social distancing, physiological and morphological measurements could not be conducted which would have yielded further insights into the study population. mailto:habibn@uj.ac.za l1: effects of social context on handgrip strength performance among less active people living with hiv dr laura gray1, prof fabienne d'arripe-longueville2, dr maxime deshayes3, prof serge s. colson2 phasrec, north west university1, lamhess, université côte d'azur2, papsa, université de nîmes, apsyv3 laura.liora.gray@gmail.com background: despite the multiple benefits of physical activity (pa) people living with hiv (plhiv) remain insufficiently active. as nonexercisers are perceived as less healthy, less active and less strong, it is likely that plhiv would be subject to the social context they are exposed to. based on the stereotype threat theory, this study looked to explain the effect of the emerging nonexerciser stereotype on handgrip strength performance among less active plhiv. we also looked to observe the moderating role of selfefficacy in the relationship between stereotype activation and performance. methodology: eighteen plhiv were recruited to participate in two experimental sessions in which both a stereotypical context and self-efficacy were manipulated. participants performed, in two randomized testing sessions (i.e., high self-efficacy and low self-efficacy), a handgrip task comprising a 15-s fatiguing maximal voluntary isometric contraction (mvc) exercise preceded (pre) and followed (post) by 5-s mvcs. in each session, four experimental conditions (i.e., control 1; control 2; stereotypical; selfefficacy) were performed. results: a significant performance decrease of the 15-s fatiguing mvc exercise was systematically observed when the nonexerciser stereotype was induced (0.01<p<0.001). in addition, this performance re-increased after a high self-efficacy manipulation (p<0.001). preand post-fatiguing exercise 5-s mvcs were also significantly depressed after the stereotypical condition (0.01<p<0.001) and improved following high self-efficacy manipulation (p<0.001). conclusion: our results revealed a classical detrimental stereotype threat effect on performance during a handgrip task when the nonexerciser stereotype was activated among less active plhiv. when high self-efficacy feedback was given, participants’ performance increased significantly whereas no significant difference was observed between the stereotypical and low self-efficacy conditions. these results indicate that self-efficacy can modulate the deteriorating effect of a negative exercise stereotype on task performance in less active plhiv. mailto:laura.liora.gray@gmail.com l2: the effect of psycho-social health on the coronary heart disease risk index among employees in a financial institution of south africa swanepoel, m1, labuschagne, r1, rothmann, j.c2, rothmann, s. jr2, de beer, l.t2, strydom, g.l1, monyeki, m. a.1 physical activity, sport and recreation focus area: north-west university1, workwell research unit: north-west university2 12262404@nwu.ac.za background: psycho-social risks (psr) appear to be among numerous risks found in the workplace which cause major concern and challenge to occupational health research. the purpose of this study was to describe the effect of psycho-social health on the coronary heart disease risk index (chdri) among employees in a financial institution in south africa. methodology: a cross-sectional design was used, involving an availability sample of 956 employees, aged 20 60 years in one of the largest financial institutions in south africa. body weight (kg) and height (cm) were measured in accordance with standard procedures and were used to calculate body mass index (bmi). the clinical measurements of systolic blood pressure (sbp), diastolic blood pressure (dbp), total cholesterol concentration (tc) and blood glucose (glu) were determined according to standard procedures. the chdri questionnaire comprises 14 identified coronary heart disease (chd) risk factors (modifiable and non-modifiable) and were weighted according to the risk to calculate chdri and were stratified according to the following cut-points: ≤ 21 = low risk; 22 30 = moderate risk and ≥ 31 = high risk. additionally, psychological ill health (psycho-social stress symptoms, stress-related physical ill health symptoms and burnout risk questionnaire) were used to determine the psycho-social risk status. results: the results indicated that 17% of the employees ran a high risk for chd and that the risk increased in older employees (40.1%). additionally, physical ill health and burnout risk appeared to be high, with female employees being mostly affected. significantly high mean values (x ̅= 6.50 ± 2.51; x ̅= 5.15 ± 2.59) and a medium practical effect (d = 0.52; d = 0.56) for psycho-social as well as physical ill health was found in the chdri high-risk group compared to the low-risk group. when the anova was calculated the results showed that in all three variables, statistical significant differences occurred between the groups (lowvs. high chdri) with psychological stress symptoms f(2) = 16.060, p = 0.001; physical stress symptoms f(2) = 18.165, p = 0.001 and burnout risk f(2) = 3.735, p = 0.025. a significant mean difference (p ≤ 0.05) effect of psycho-social ill health in the low and high-chdri groups, with a medium practical significant effect size (d = 0.53) was found. additionally, physical ill health showed a significant mean difference (p ≤ 0.05) effect on the low and high-chdri groups, with medium practical significance (d = 0.57). when comparing the burnout risk effect in the low and highchdri group, a statistically significant difference (p ≤ 0.05) with small practical significance (d = 0.23) was found. conclusion: it can be concluded that the presence of psycho-social ill health among employees in a financial institution in south africa contributes to a high risk for chdri. given the health implications of these findings for the total well-being of the employees, multiple-component interventions at work sites improve workers’ chdri and psycho-social ill health. mailto:12262404@nwu.ac.za m1: physical activity and physical fitness of older adult women from urban and periurban area of maputo-mozambique timoteo daca1, antonio prista1 physical activity and health research group, faculty of physical education and sports, pedagogical university of maputo, mozambique1 dacajunior@gmail.com background: physical activity (pa) and physical fitness have an important impact on health in the general population including ageing people. factors that affect the levels include the living environment which has a strong variability. aim: the aim of the present study was to evaluate the relationship between health indicators of older adult women living in urban (ub) and peri-urban (pu) areas of maputo, mozambique methodology: a total of 69 older adult women (age=67.0+6.6 years) participated in this study and were residents in ub (44.9%) and pu (55.1%) areas. body mass index (bmi) was calculated from height (m2) and weight (kg) and participants were classified (normal; overweight and obese) after the standard procedures of evaluation. moderate to vigorous physical activity (mvpa) was assessed by an accelerometer for 7 days. activities levels (pal) were classified in low and high 30 min of mvpa. functional physical fitness (fpf) included muscle strength (fm) and cardiorespiratory fitness (acr) evaluated by the senior fullerton test battery procedure (rikli & jones 1998). the independent t-test was used for comparisons and the person correlation to estimate the relationship between the variables. results: no significant statistical differences were found between ub and pu in bmi, mvpa and fpf tests (p>0.05). the prevalence of overweight and obesity was 20.3% and 47.8%, respectively. the subjects have low (18.8%) and higher (75.4%) pal. bmi was positively correlated with fat (r=0.827; p<0.001) and negatively correlated with acr (r=-0.415; p<0.001). the acr was also negatively correlated with mvpa (r=-0.263; p<0.05). conclusion: the prevalence of cardiovascular health risk factors sense to be evident in older adult women, independent of the residential area of maputo city. mailto:dacajunior@gmail.com m2: habitual physical activity in children and young from urban and rural areas of mozambique gomes nhaca1, timoteo daca1, antonio prista1 physical activity and health research group, faculty of physical education and sports, pedagogical university of maputo, mozambique1 nhacagomes@gmail.com background: studies are showing that habitual physical activity (hpa) of children and young people is drastically reducing in different areas in mozambique, with repercussions for the quality of life and wellbeing. aim: the aim of this study was to evaluate and compare the hpa of children and young living in rural and urban areas. methodology: a total of 3 422 children and young (boys= 49.9%; girls=50.1%) aged 6 to 17 years from urban centre (urb = 52.3%), a rural area (rur=23.4%) and an island (ila=24.3%) regions were evaluated. the body mass index (bmi) was calculated and the habitual physical activity (hpa) was estimated by the questionnaire (prista et al 2000). subjects’ body composition (bc) was classified by bmi (low, normal, overweight and obese). levels of activity were compared by activity scores the dimensions of domestic activities (dom), games (gam) sports (spo), walking (wal), watching tv (wtv) and total activity (tot). one-way anova and independent t-test were used for comparisons. results: prevalence of body composition were low=8.7%, normal=82.3%, overweight=5.6% and obese=3.1%. bmi were higher in urb subjects (urb=18.4±3.5; rur=16.4±2.3 and ila=17.3±3.1; p=0.001). time spent by activity domains was different by region group. rur subjects performed more time in dom than urb and ila (43.7±24.1 vs 12.3±11.2 and 30.3±18.9; p=0.001). ila subjects play more gam (37.2±21.1 vs 22.5±14.7 and 24.6 ±18.2; p=0.001) and walk (14.6 ±3.8 vs 12.3±3.9 and 9.0 ±4.3; p=0.001) than rur and urb. time in spo was higher in urb and ila than rur (17.1+14.9 vs 17.4 + 20.1 and 9.2+9.3; p=0.001). the tot coefficients were higher in ila, followed by rur and urb (99.6±44.4 vs 87.7±34.4 and 63.4±31.9; p=0.001). concerning gender, girls outperform boys in tot (79.6+39.7 vs 77.5+38.7; p=0.039). conclusion: patterns and intensities of energy expenditures are strongly influenced by the area of residence of children and youth in mozambique. mailto:nhacagomes@gmail.com m3: physical activity levels of adult male and female from a peri-urban area of maputo-mozambique jorge uate1, ivalda macicano2, timoteo daca1, antonio prista1 physical activity and health research group, faculty of physical education and sports, pedagogical university of maputo, mozambique1, national institute of health, mozambique2 uateja@gmail.com background: risk factors for cardiovascular diseases are associated with gender and physical activity. studies in this topic in peri-urban african settings are scarce. aims: the aim of this study was to compare the activity levels between adult males and females living in “polana caniço”, a peri-urban area of maputo, mozambique. methodology: a total of 144 adults (males= 46.5%; females=53.5%; age=31.5+11.9 years) participated in the study. body mass index (bmi) was calculated from height and weight and physical activity level (pal) was estimated by an accelerometer, used for seven consecutive days. time in sedentary (spa), light (lpa) and moderate to vigorous physical activity (mvpa) were determined by accelerometer data. results: percentage of overweight subjects were higher in females (males=13.4%; females=17.1%; p<0.05) as well as obesity (males= 6.0%; females=22.4% ; p<0.05). average daily time in sedentary activities were significantly higher in females (males=9 894±5 248; females=11 887±9 017; p=0.002), while males spent more time in mvpa (males=42.8±32.3 and females = 18.7±14.0; p=0.001). the percentage of those who accomplished 60 minutes or higher time in mvpa was higher in males (25.4%) than in females( 1.3%). conclusion: prevalence of overweight, obesity and insufficient physical activity are already at a concern levels being higher in females. mailto:uateja@gmail.com m4: effects of the emerging non exerciser stereotype on performance on a fatiguing task in active and less active healthy young adults laura gray1, maxime deshayes2, serge s. colson3, fabienne d'arripe-longueville3, corentin clémentguillotin3 phasrec, north west university1, papsa, université de nîmes, apsy-v2, lamhess, université côte d'azur3 laura.liora.gray@gmail.com background: perceptions of active and inactive people are conveyed by society and a nonexerciser stereotype has emerged. past research has focused on information formation with nonexercisers perceived, by both exercising and non-exercising people, as less healthy, less energetic, unfit, less strong and weaker. we know, however, that stereotype threat can contribute to the underperformance of individuals belonging to a range of negatively stereotyped groups and in several domains. furthermore, fatigue is an important indicator of performance. the present study sought to observe the effect of the nonexerciser stereotype on performance in a fatiguing task. methodology: we used physical activity questionnaires to recruit and compare 13 male nonexercisers and 13 male exercisers’ performance on the fatiguing task, consisting of executing intermittent contractions until exhaustion. participants completed a familiarisation session as well as stereotypical and nullified sessions. results: a significant condition main effect (i.e., nullified and stereotypical) was shown, f(1, 24) = 40.42, p < .001, η2 = .63. indeed, this condition main effect was contrary to classic stereotype threat effects, as nonexercisers under stereotype threat improved their performance as revealed by increased time to exhaustion on the fatiguing task. exercisers also increased their performance when under stereotype threat, in line with the stereotype lift effect. a significant condition main effect also appeared for the rate of perceived exertion (rpe) slope, f(1, 24) = 6.88, p = .015, η2 = .23. the rpe increase was greater in the nullified condition as compared to the stereotypical condition. conclusion: these valuable results observed for rate rpe allow to suggest that rpe could be a mechanism through which performance on a fatiguing task may be affected. furthermore, this study is encouraging, in that it revealed that nonexercisers’ performance on a prolonged fatiguing task was not decreased by the negative nonexerciser stereotype. mailto:laura.liora.gray@gmail.com sajsm 477.indd original research sajsm vol. 25 no. 4 2013 109 objective. to determine whether a relationship exists between the functional movement analysis (fma) score and lower-body injury rates in high-performance adolescent female football players. method. observations included a baseline fma score and medical injury reports. data were collected from 24 players’ injury and illness records over a 38-week training period. all football injuries requiring medical attention (including stiffness, strains, contusions and sprains) and/or the removal from a session, leading to training restriction, were included in the study. off-season weeks were excluded. pearson’s product-moment correlation coefficient was calculated to assess the strength of the linear relationship between the fma score and the number of medical visits, and between the number of medical visits and the number of training-restriction days. results. there was no evidence of a relationship between the fma score and injury risk in teenage female football players (r=0.016; p=0.940). a strong indication of a cyclical season in the training schedule was noticed over the 38-week study period. a substantive negative correlation (r=-0.911; p=0.032) was seen in the number of medical visits compared with the training-restriction days. injuries during two peak periods could have resulted from overuse, increased training load, stress and overtraining. conclusion. it could not be shown that a high fma score was associated with a lower risk of injury. the ultimate goal is thus to reduce recurrent injury in players with a high fma count. the regular medical visits observed suggest that player condition is maintained by means of reducing injury and managing training-restriction days. our findings are in accordance with previous studies in terms of the lower limb being the most frequent region of injury, specifically the knee. this study supports previous suggestions that it is essential to develop a prevention strategy to measure trauma and recovery. s afr j sm 2013;25(4):109-113. doi:10.7196/sajsm.477 the relationship between functional movement analysis and lowerbody injury rates in adolescent female football players d c janse van rensburg, md; a jansen van rensburg, msc; p c zondi, mb chb; s hendricks, ba (hons) sport science; c c grant, phd; l fletcher, phd section sports medicine, university of pretoria, pretoria, south africa corresponding author: d c janse van rensburg (christa.jansevanrensburg@up.ac.za) football, one of the most popular team sports worldwide according to the fédération internationale de football association (fifa) survey of 2006, is increasing in popularity, especially among young female players. [1] this high participation rate also associates football with a high injury risk, especially in teenage players. numerous studies have found female players to be more prone to injury than their male counterparts.[2] this is especially true for youth players in competition, as they show a higher injury rate per match than their seniors.[3] although there have been epidemiological injury studies on female football in recent years, most of these focused on elite female players. [4] there are limited publications available on epidemiological injury records in adolescent female football players. in a 2001 2009 study by waldén et al.,[5] female football players showed a two-fold increase in injury incidents compared with their male counterparts in the same age group. emery[6] and söderman et al.,[7] performed two other studies on injury rates in female adolescent players, focusing on the 12 18and 14 19-year age groups, respectively. however, these studies looked only at injury prevalence over 3[6] and 7 months,[7] respectively, which may not be sufficient to attain reliable injury incidents, taking all factors of a long season into account. many of these injuries may have long-term consequences that include an extended phase of rehabilitation and inability to perform sports, as well as the possibility of incomplete recovery that could cause lasting disability for the injured player. understanding and identifying injury risk factors are essential to developing and improving methods to prevent injuries. [8] compensatory and incorrect movement tactics are often used by players in an effort to achieve higher performance. these improper actions may emphasise poor body movement patterns during play, resulting in injury. in 2003, the fifa medical and research centre (f-marc)[9] developed a structured training programme, ‘the 11’, aimed at amateur players aged 13 17 years and focused on core stability, lower-extremity strength, neuromuscular control and agility. the objective of this programme was to prevent or lessen injury and thereby possibly enhance performance. a review of the original programme confirmed the potential to decrease injuries, but compelling evidence was not obtained due to poor compliance. revisions to ‘the 11’ in 2008, and later in 2010, improved the efficacy of the intervention, with research showing a 30% reduction in the risk for minor injuries, and as much as a 50% reduction in the risk for severe injuries such as anterior cruciate ligament (acl) sprains.[10] as with standard warm-up exercises, this programme should be performed at least twice a week at the start of each training session. another warm-up prevention programme that has been shown to reduce injuries significantly, specifically non110 sajsm vol. 25 no. 4 2013 contact acl injuries, is the prevent injury, enhance performance (pep) programme developed by the santa monica orthopaedic and sports medicine research foundation. this programme has been shown to reduce acl injuries by up to 60 89%. however, 6 8 weeks of consistency is required for these changes to be effective.[11] other intervention programmes have also been shown to reduce injury risks in athletes, if implemented appropriately. the functional movement screen (fms) is a validated and reliable screening tool consisting of seven different exercises that highlight any functional or biomechanical limitations during specific movement sequences.[8] the athlete is scored from 0 to 3 depending on how well the movement is executed, with 3 being the best. an athlete with a functional limitation or weakness will have a lower total fms score and is at increased risk of injury when participating in sport. the fms was designed by cook et al.[12] to assess the balance of mobility and stability required to perform essential movements. the movements require specific neuromuscular co-ordination in a range of occupational and physical tasks. use of the fms score as a baseline for correcting movement in a rehabilitative setting could remove the primary injury risk factor in predicting performance durability or subsequent injuries.[13] these scores could be used during pre-season or baseline sports physicals to identify athletes with pain or movement limitations before the athletic season commences. researched factors for injuries include poor mobility, stability, core strength and asymmetries.[8] the functional movement analysis (fma) programme is based on the fms,[12] and is designed to evaluate the functional movement ability of an athlete off the field. additional movements are included for further assessment of posture and pelvic stability. to differentiate from the fms, the assessment scoring system has also been adapted from 1 to 4 to allow a better reflection of the different competencies, and to monitor improvements of functional movement more effectively. a training team of 24 adolescent female football players was the target group in this study. the group represented a high-performance squad recruited by national selectors at various tournaments throughout south africa. the players were selected based on football skill and athletic potential. they were housed at a high-performance unit, where they received coaching and conditioning by national trainers and had unlimited access to sports science and medical interventions. the objective of this study was to examine the correlation between fma score and lower-body injury rates in adolescent female football players aged 13 18 years over a 38-week training period. methods population this was a descriptive pilot study based on the results of the highperformance programme of the 2012 safa/lotto basetsana football academy at the university of pretoria in south africa. twenty-four adolescent female football players participated in the investigation. the players, aged 13 18 years, were assigned over a 38-week training period (january to september 2012). this period coincided with the athletes’ respective training and tournament season. it excluded the off-season period of october december 2012. injuries and illnesses injury and illness surveillance included assessment by doctors and physiotherapists. players had free access to the medical staff at all times. attention was given to all football injuries requiring medical attention (including stiffness, strains, contusions and sprains) and/or the removal from a session, leading to training restriction. procedures at the start of the study, height, weight and body mass index (bmi) were determined. observations included a baseline fma score and medical injury reports. participants qualified for inclusion in the study if they participated in regular physical activity at a competitive level. participants were excluded if they used any orthotic device or joint aid (e.g. knee brace), or reported any recent (<6 weeks) musculoskeletal or head injury likely to have an impact on fitness performance on the fma. athletes received a zero score if pain was related to any part of the tests. the fma analysis is an adaptive version of the fms as described by cook et al.,[12] and entails ten movement assessments: posture, flexibility, shoulder mobility, one-legged squat, one-legged jump, overhead jump, lunge, rotational stability, trunk stability and bridging. the scoring system on the fma assessment ranges from 1 to 4, with 4 being the best possible score. the best total score that can be achieved on the fma is 40. intra-tester reliability has been shown to be most reliable when testing is performed by one person with a minimum of 6 months of experience in addition to clinical experience.[14] therefore, in this study, only one tester was used, with 5 6 years of experience in the fms testing procedure. statistical analysis the pearson product-moment correlation coefficient, r – a measure of the linear association between two variables – was used to quantify the relationship between fma and the total number of medical visits, as well as the relationship between the total number of medical visits and training-restriction days. the level of significance was set at the conventional p≤0.05. results during the 38-week study period, 24 players were evaluated (table 1). the overall weight, height, age and bmi of the participants compared well with those of player groups used in similar reported studies. the fma score rated average according to the fma score card. during the 38-week study period, 15 of the 24 players reported a total of 38 medical visits. a high number of medical visits was not only observed in players with a low fma score, but across a wide range of fma scores (fig. 1). pearson’s correlational analysis confirmed a non-significant relationship (r=0.016; p=0.940) between fma and the number of medical visits. two distinctive peaks were evident in the number of medical visits during march and august: 13 and 9, respectively (fig. 2). a slight increase and a definite drop in medical visits was evident in the months preceding and following the peak periods. fig. 3 depicts that the documented training-restriction days and the sum of medi cal visits peaked simultaneously during the months of march and august. the elevated training-restriction peak in march was evidently preceded by a slight increase in february and a gradual decline in april. pearson’s correlational analysis confirmed a significant relationship (p=0.032; r=-0.911) between the reported number of sajsm vol. 25 no. 4 2013 111 medical visits and the number of trainingrestriction days. training restriction was placed mainly on injuries in the knee, foot and ankle regions (fig. 4). however, during the 38-week period, the knee followed by the lower leg, thigh, lower back and hip accounted for the highest incidence of injury. although injuries were high in the lower leg, thigh, lower back and hip area, no training restrictions were documented. injuries in these areas can therefore be considered less serious than in the foot and ankle regions, where training restrictions were recorded. the mechanism of injury, in particular ‘overuse’ and ‘forced extension’, peaked during the months of march, and ‘overuse’ peaked again in august (fig. 5). overuse was graded as a gradual-onset injury, while forced extension, fl exion and rotation, and blunt injury were categorised as acute-onset injuries. muscle stiff ness and strains accounted for 16 injuries (28% each) and were the most frequent occurring specific injury types identifi ed. other injury types were sprains (17%) and contusions (10%). discussion th ere was no signifi cant correlation between fma score and injury risk in the players. however, a strong negative correlation (r=-0.911; p=0.032) was found between the number of medical visits and the trainingrestriction days. a strong indication of a cyclical season in the training schedule was noticed during the 38-week period. lowerbody injuries in these two peak periods could have resulted from overuse, increased training load, stress and overtraining. in previous studies, a lower fms score had a predictive ability and was a predisposing factor for injury in male participants in active military service,[15] as well as in male athletes in american football.[8] the same is true for female athletes, although not necessarily female football athletes, with very few studies in this regard. [13] further studies, such as this one, are warranted to determine fms scores and injury prevalence among young female athletes. previous research has confirmed that the screen ing of movement patterns can readily identify functional limitations and asymmetries, and can be used to lower injuries in high performers.[8] in the current study, the fma as a score card was assessed relative to the number of recorded medical visits among the football players. however, the correlational analysis did not substantiate that a high fma score would directly lead to fewer medical injuries. th e number of medical visits and trainingrestriction days peaked during the months of march and august. th is could indicate a cyclical season in the training schedule of the players, during which injuries could have resulted from overuse, increased training load, stress and overtraining. th e trainingtable 1. baseline physical characteristics of female participants (13 18 years) (n=24) age (years), mean (±sd) body weight (kg), mean (±sd) height (cm), mean (±sd) bmi (kg/m2), mean (±sd) fma score, mean (±sd) total medical visits, n players who reported medical visits, n total training restriction days, n study period (weeks) 15.7 (±1.3) 54.9 (±9.04) 164.0 (±5.95) 20.3 (±2.61) 29.5 (±2.9) 38 15 29 38 fma = functional movement analysis. 40 35 30 25 20 15 10 5 0 m ed ic al v is its (n =3 8) v . f m a sc or e participants (age 13 18 years) (n=24), n fma medical visits 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 fig. 1. number of medical visits in the 38-week study period v. total fma score. 14 12 10 8 6 4 2 0 ja n months in 2012 (38 weeks) m ed ic al v is it s, n (n = 38 ) fe b m ar a p r m ay ju n ju l a u g se p fig. 2. number of medical visits over the 38-week study period. 112 sajsm vol. 25 no. 4 2013 restriction peaks could also have been due to the fact that many of the players represented their respective u17 and u20 national teams during the same year. it has been shown that it is during competition where most incidences of injuries in female footballers occur.[3] th e specifi c time-frame of this research coincided with the respective training and tournament seasons of the players, stretching over a 38week period. baseline training and fitness occurred during january and february. more sport-specifi c skills training with increased load (i.e. quality and quantity specific) commenced in march, with mid-week and weekend matches in august. the study period excluded the off -season segment of 3 months. the fact that a strong, negative correlation was found between the number of medical visits and training-restriction days further indicates that regular medical visits may maintain player condition in reducing injury and managing total restriction days. injuries in football players have signifi cant implications, not only in relation to future participation in physical activity, but also in future morbidity and mortality related to physical inactivity. th erefore, the reduction of injuries is critical. injury prevention or a protective intervention training programme will help to lower football-related injuries. according to emery et al.,[16] the risk of injury in youth indoor football players can be reduced by more than one-third with a football-specifi c neuromuscular training programme. also with football being a team sport and players required to be at a high level of performance for the season, variation in training should be considered. periodisation or fluctuation of high and low training loads (including changes in volume, intensity and strength training) within a small time-period, as well as balanced periods of rest and recovery, have proven to benefi t performance and reduce the risk of injury.[17] in this study, the knee was the most injured region followed by the lower leg, thigh, lower back and hip. th e lower leg, thigh, lower back and hip injuries were, however, less serious, since training restrictions were placed mainly on injuries of the knee, foot and ankle. th e knee, foot and ankle regions can therefore be considered to be highly vulnerable areas of the football player’s body, which may also lead to lengthy exercise-restriction periods in the event of injury. this is consistent with other studies listing the most common injury locations in female football players as the knee, ankle and thigh.[18] improved preparation and training, and a structured workout schedule with a specific area of focus, will ensure reduced training restraints of athletes.[19] months in 2012 (38 weeks) medical visits training-restriction days tr ai ni ng -r es tr ic ti on d ay s v. m ed ic al v is it s 2 4 6 8 10 12 14 16 18 20 0 ja n fe b m ar a pr m ay ju n ju l a ug se p fig. 3. number of medical visits v. training-restriction days over the 38-week study period. region count training-restriction days25 20 15 10 5 0 re gi on c ou nt /t ra in in g re st ri ct io n da ys region of injury h am st rin g q ua d g ro in a nk le o th er lo w er le g th ig h lo w er b ac k h ip kn ee fo ot fig. 4. region of injury v. training-restriction days in the 38-week study period. months in 2012 (38 weeks) 7 6 5 4 3 2 1 0 m ec h an is m o f i n ju ry overuse forced extension flex and rotation blunt injury other ja n fe b m ar a p r m ay ju n ju l a u g se p fig. 5. mechanism of injury over the 38-week study period. sajsm vol. 25 no. 4 2013 113 the high rate of injury seen in a recurrent or increased pattern over specific months suggests the need for the implementation of a specific injury-prevention training approach. soligard et al.[10] in 2008 indicated that players, in particular young female football players, could only benefit from proper biomechanical technique and improved awareness exercises to lower the risk of injury. lerch et al.[20] is in agreement with this in his literature review demonstrating the effectiveness of injuryprevention programmes in female youth football players. due to the results of the mechanism of injury reported in this study showing overuse injuries as a peak, along with the suggestion of the cyclical seasoning in the training schedule of the players, it would be beneficial for the trainers to utilise different methods of quantifying training load – so as to provide a more quantitative measure of internal load on each player, to avoid overuse injuries and over-reaching.[21] while this will not affect performance,[22] it will allow for reliable internal load to be recorded and specific training prescription to be given accordingly,[23] which, in the long term, will assist in injury prevention and consequently player longevity. musculoskeletal injuries accounted for the majority of injuries in training. the most frequent occurring specific injury types were stiffness and strains. although sprains and contusions occurred less frequently, these specific injury types can also be classified as acute-onset injuries. thus, it seems that acute-onset injuries are a bigger concern than gradual-onset injuries. this varies, with previous research showing that young female footballers tended to sustain fewer strain injuries and an increased number of ligament injuries than their male counterparts of equivalent age.[24] conclusion it could not be shown that a high fma score was associated with a lower risk of injury. the ultimate goal will thus be to reduce recurrent injury in players with a high fma count. our results agree with previous studies in terms of the most frequent region of injury being the lower limb, specifically the knee. our study thus supports previous suggestions that it is essential to develop a prevention strategy to measure trauma and recovery. trainers, coaches and medical staff may well consider monitoring the female football-training programme, the training load, the duration of training as well as the matches and the psychosocial recovery (monitoring the stress and strain) of each player. due to the large variation between players, the individual variances over time are most substantial in relation to injury prevention. trainers need, therefore, to gain information on an individual basis to identify when a player has an increased risk of injury. if necessary, the training schedule can be adapted or interventions used in which players are educated to manage injury in a better manner. areas of future study include quantitative recording of the training programme to correlate high peak injury occurrences with high peak training cycles. recording and quantifying the internal load and recovery of players will allow future researchers to deduce more precise risk factors and trends for injury prevalence. while this study looked at the trends during a 38-week training period, it may be more reliable for future researchers to track similar trends over multiple seasons, allowing an intricate analysis into the cyclical training, season by season. increased intra-tester reliability for fms testing will strengthen future studies. acknowledgements. amy bathgate is acknowledged for assistance with data collection. references 1. fifa. fifa big count 2006: 270 million people active in football. http://www.fifa.com/ aboutfifa/media/newsid=529882.html (accessed 14 january 2013). 2. emery ca, meeuwisse wh, hartmann s. evaluation of risk factors for injury in adolescent soccer: implementation and validation of an injury surveillance system. am j sport med 2005;33:1882-1891. 3. junge a, dvorak j. injuries in female football players in top-level international tournaments. br j sports med 2007;41(suppl 1):i3-i7. 4. faude o, junge a, kindermann w, dvorak j. injuries in female soccer players: a prospective study in the german national league. am j sports med 2005;33(11):16941700. 5. waldén m, hägglund m, magnusson h, ekstrand j. anterior cruciate ligament injury in elite football: a prospective three-cohort study. knee surg sports traumatol arthrosc 2011;19(1):11-19. [http://dx.doi.org/10.1007/s00167-010-1170-9] 6. emery ca. injury prevention and future research. med sport sci 2005;49:170-191. [http://dx.doi.org/10.1159/000084289] 7. söderman k, adolphson j, lorentzon r, alfredson h. injuries in adolescent female players in european football: a prospective study over one outdoor soccer season. scand j med sci sports 2001;11(5):299-304. 8. kiesel k, plisky pj, voight m. can serious injury in professional football be predicted by a preseason functional movement screen? n am j sports phys ther 2007;2(3):147158. 9. f-marc. http://www.fifa.com/aboutfifa/footballdevelopment/medical/aboutus/ fmarc/index.html and http://www.fifa.com/mm/document/footballdevelopment/ medical/01/47/88/06/f-marcfootballforhealth.pdf (accessed 14 january 2013). 10. soligard t, nilstad a, steffen k, et al. compliance with a comprehensive warm-up programme to prevent injuries in youth football. br j sports med 2010;44(11):787793. [http://dx.doi.org/10.1136/bjsm.2009.070672] 11. mandelbaum br, silvers hj, watanabe ds, et al. effectiveness of a neuromuscular and proprioceptive training program in preventing anterior cruciate ligament injuries in female athletes: 2-year follow-up. am j sports med 2005;33(7):1003-1010. [http:// dx.doi.org/10.1177/0363546504272261] 12. cook g, burton l, hoogenboom b. pre-participation screening: the use of fundamental movements as an assessment of function part 1. n am j sports phys ther 2006;1(2):62-72. 13. chorba rs, chorba dj, bouillon le, overmyer ca, landis ja. use of a functional movement screening tool to determine injury risk in female collegiate athletes. n am j sports phys ther 2010;5(2):47-54. 14. gribble pa, brigle j, pietrosimone bg, pfile kr, webster ka. intrarater reliability of the functional movement screen. j strength cond res 2013;27(4):978-981. [http:// dx.doi.org/10.1519/jsc.0b013e31825c32a8] 15. teyhen ds,  shaffer sw,  lorenson cl,  et al. the functional movement screen: a reliability study. j orthop sports phys ther 2012;42(6):530-540. 16. emery ca, meeuwisse wh. the effectiveness of a neuromuscular prevention strategy to reduce injuries in youth soccer: a cluster-randomised controlled trial. br j sports med 2010;44:555-562. [http://dx.doi.org/10.1136/bjsm.2010.074377] 17. lambert mi. periodisation and monitoring of overtraining in rugby players. http:// www.sarugby.co.za/boksmart/pdf/boksmart%20-%20periodisation%20and%20 monitoring%20of%20overtraining%20in%20rugby%20players.pdf (accessed 14 january 2014). 18. giza e, mithofer k, farrell l, zarins b, gill t. injuries in women’s professional soccer. br j sports med 2005;39(4):212-216. [http://dx.doi.org/10.1136/bjsm.2004.011973] 19. le gall f, carling c, reilly t. injuries in young elite female soccer players: an 8-season prospective study. am j sports med 2008;36(2):276-284. 20. lerch c, cordes m, baumeister j. effectiveness of injury prevention programs in female youth soccer: a systematic review. br j sports med 2011;45:359-359. [http:// dx.doi.org/10.1136/bjsm.2011.084038.140] 21. alexiou h, coutts aj. a comparison of methods used for quantifying internal training load in women soccer players. int j sports physiol perform 2008;3(3):320-330. 22. brink ms, nederhof e, visscher c, schmikli sl, lemmink ka. monitoring load, recovery, and performance in young elite soccer players. j strength cond res 2010;24(3):597-603. [http://dx.doi.org/10.1519/jsc.0b013e3181c4d38b] 23. impellizzeri fm, rampinini e, coutts aj, sassi a, marcora sm. use of rpe-based training load in soccer. med sci sports exerc 2004;36(6):1042-1047. 24. junge a, cheung k, edwards t, dvorak j. injuries in youth amateur soccer and rugby players – comparison of incidence and characteristics. br j sports med 2004;38(2):168172. [http://dx.doi.org/10.1136/bjsm.2002.003020] introduction according to the federation of international football associations (fifa), in 2006 there were approximately 38 million registered soccer players and 226 unregistered occasional players in 207 member countries worldwide. the total number of soccer players has increased by 10% over a 6-year period. 1 taking the increased popularity of the game and the high expectations of the players into consideration, the number of injuries associated with soccer could be anticipated. 2 soccer carries a risk for fractures, sprains, dislocations and other injuries. according to the centers for disease control and prevention (cdc) 3 in the usa, soccer injuries in male players accounted for 4.6% and 3.8% of non-fatal, unintentional sportsand recreation-related injuries in the 15 -19-year and 20 24-year age groups, respectively. most soccer injuries involve the lower extremities, are mild to moderate, and are typically sprains or contusions. 2,4-8 morgan and oberlander 7 reported that 77% of injuries in major league soccer players in the usa involved the lower extremity, with the knee slightly more often affected than the ankle. several studies reported that more injuries occurred during matches than during practice. 2,7,8 an injury rate of 2.9 per 1 000 hours of practice, as opposed to 35.3 per 1 000 hours of match play, was noted by morgan and oberlander. 7 in a study of the epidemiology of soccer injuries conducted in nigeria, 2 it was found that strikers and defenders were most commonly injured, especially those playing in amateur leagues. the majority of injuries are sustained within the first month of a new season. kofotolis et al. 6 reported a 7 8 times higher rate of ankle original research article incidence of injuries among male soccer players in the first team of the university of the free state in the coca cola league – 2007/2008 season abstract objective. to determine the incidence, nature and severity of injuries among male soccer players in the first soccer team of the university of the free state (ufs) in the coca cola league during the 2007/2008 season. informed consent was obtained from the players and the study was approved by the ethics committee of the faculty of health sciences, ufs. design. a cohort descriptive study was conducted. setting. twenty-three league matches were attended, during which injury information was recorded on game sheets. main outcome measures. the injury type and site, the player game time, and the game period during which the injury occurred were recorded. follow-up questionnaires were completed for injured players. results. in 23 matches played, a total of 15 injuries were sustained by 10 players. the incidence of injuries per 1 000 hours game time was 39.5. more injuries occurred at the beginning of the season. midfield players were most often injured (53%). most injuries were minor (class 1 severity), and none exceeded class 3 severity. most injuries occurred in the first or fourth quarter of the game. knee and ankle injuries were the most common (27% and correspondence: dr nicolas theron super sport health and adventure club po box 20151 willows bloemfontein 9320 south africa tel: 27-51-448-1389 fax: 27-86-529-3148 e-mail: nicolast@iafrica.com robert bailey (mb chb student)1 louisa erasmus (mb chb student)1 laetitia lüttich (mb chb student)1 nicolas theron (mb chb, m fam med)2 gina joubert (ba, msc)3 1 school of medicine, faculty of health sciences, university of the free state, bloemfontein 2 private practitioner, super sport health and adventure club, bloemfontein 3 department of biostatistics, faculty of health sciences, university of the free state, bloemfontein 47%, respectively), consisting mainly of sprains sustained while being tackled. conclusion. the most common soccer injuries incurred were to the lower extremity. the relatively low impact nature of the sport resulted in mild to moderate injuries. the incidence of injuries decreased as the season progressed. the results of this study were consistent with those of similar studies reporting the incidence of soccer injuries. sajsm vol 21 no. 1 2009 � � sajsm vol 19 no. � 2007 injuries during the first 2 months compared with the last month of the season. players with a history of previous injuries were also found to be more prone to sustaining further injuries. 6 the aims of our study were: (i) to determine the number of injuries incurred per 1 000 hours of game time in first team soccer players of the university of the free state (ufs); and (ii) to describe these injuries with regard to the age of the injured player, his position on the field, previous injuries and how recently these injuries were incurred, the area of the body where the injury was sustained, the mechanism of play, the period of the game when the injury occurred, and the nature and severity of the injury. methods the terms ‘football’ (i.e. not american football) and ‘soccer’ were regarded as synonyms. for the purpose of the study, ‘injury’ was defined as an injury that occurred during any of the soccer matches observed during the study, resulting in the participant being out of the competition on the day of the injury, or causing the player to miss any practices or matches after the day of the injury. ‘incidence’ was defined as the number of new injuries per 1 000 match hours. match time did not include warm-up exercises before the match. a cohort descriptive study was conducted. the study population consisted of male soccer players who played for the first team of the ufs during the 2007/2008 season. only players actively participating in the match on the field were included. when any replacement player had to go onto the field, his playing time was included in the study. no sample selection was performed. every player fulfilling the inclusion criteria was requested to voluntarily participate in the study. the ufs first team was selected for the study as they participated in the coca cola league and played matches on a regular basis. twenty-three matches played geographically close to bloemfontein from august 2007 to january 2008 were covered by the study. the target population included 16 players, of whom 11 were members of the first team and 5 were replacement players (reserves) participating in any of the 23 matches. the estimated game time was 379.5 hours, calculated by 11 players x 23 games x 90 minutes per game. the information of players sustaining an injury during the time period in which the study was conducted, was recorded on specially designed game sheets. two researchers attended each game and compiled separate game sheets, which were compared after the match to detect if there were any discrepancies. a follow-up questionnaire containing a data capture sheet was administered in the form of a structured interview. the follow-up interviews were all conducted within 1 month of a player sustaining an injury. the reliability of the information obtained by the game sheets and follow-up interview depended of the accuracy of the recorded information by the researchers. the severity of the injury was classified according to the amount of game or practice time the player lost as a result of his injury. table i shows the classification of the severity of injuries, 9 grade 1 being a minor injury and grade 5 a serious injury. table i. classification of the severity of injuries 9 classification amount of time missed 1 not being able to finish the match owing to injury 2 missing up to 1 week of play 3 missing up to 6 weeks of play 4 missing 6 weeks 6 months of play 5 missing ≥6 months of play fig. 1. distribution of injuries per month throughout the course of the season. 8 1 4 2 0 0 2 0.3 0.5 0.4 0 0 0 2 4 6 8 10 augus t september october november decem ber january month n u m b er o f in ju ri es total injuries mean number of injuries per game fig. 1. distribution of injuries per month throughout the course of the season. fig. 2. distribution of injuries per quarter of the game. 4 2 4 5 0 1 2 3 4 5 6 1st 2nd 3rd 4th quarter of the game n u m b er o f in ju ri es fig. 2. distribution of injuries per quarter of the game. fig. 3. body areas affected by injuries sustained. 1 1 4 7 2 0 2 4 6 8 shoulder thigh knee ankle other (nose, genitals) n u m b er o f in ju ri es fig. 3. body areas affected by injuries sustained. � sajsm vol 21 no. 1 2009 the ethics committee of the faculty of health sciences, ufs, granted approval to perform the research. permission was also obtained from the vice-rector: student affairs, ufs, and the coach of the first soccer team. information regarding the objectives of the study was given to the coach and the players, and each player gave written consent to participate. all data gathered in the study were kept confidential. in order to test the methodology of the proposed investigation, a pilot study was performed on 2 matches played in august 2007 by the female first soccer team of the ufs after approval had been obtained from the coach, players and ethics committee. before each game, a complete list of players and their jersey numbers was obtained from the coach for that particular match. all information gathered by the study was treated confidentially. a record of all the players’ names and numbers on the back of their jerseys was kept safe and was only accessed by the researchers for the purpose of the study. results in 23 matches played, a total of 15 injuries were sustained by 10 players. two players sustained 3 injuries each, 1 player sustained 2 injuries, and 7 players sustained 1 injury each. no injuries occurred in 14 of the matches, 1 injury occurred in 5 matches, 2 injuries in 2 matches, and 2 matches were played in which 3 injuries occurred in each. the total and mean number of injuries per match occurring per month are shown in fig. 1. the highest number of injuries occurred during the first month of matches being played, with a steady decline in both the total and mean number of injuries per match each month as the season progressed. with regard to the position of the injured player on the field, 8 (54%) injuries occurred in midfielders, 3 (20%) each in forward and defence position players and 1 (7%) in the goalkeeper. the median age of the injured players was 22 years (minimum 20 years, maximum 35 years). twelve of the 15 injuries (80%) were classified as grade 1 severity injuries, with the injured player not being able to complete the match. two injuries (13%) resulted in the players missing up to 1 week of play (grade 2 severity), while 1 player sustained an injury of grade 3 severity and had to withdraw from play for 6 weeks. no injuries classified as grade 4 and 5 severity were incurred. the period of the game in which the injuries occurred is shown in fig. 2. most injuries occurred in the fourth quarter (5), first quarter (4), and third quarter (4) of the match. during the study, no red card was issued against a player, i.e. there were always 11 players on the field, and no extra time was played. the incidence of injuries per 1 000 hours game time was calculated as 39.5 (15 injuries x 100 ÷ 379.5 game hours). most injuries were sustained to the ankle (47%) and the knee (27%). the body areas affected by the injuries are shown in fig. 3, while fig. 4 shows the mechanism of play during which injuries were suffered. almost half of the injuries (7/15) were incurred when the player was being tackled by an opponent. nine of the 15 injuries incurred were sprains, while bruises and dislocations were sustained twice each, and cramping and bleeding once each. two of the 15 injured players had a history of previous injuries, both sprains. one player’s injury was sustained in the preceding week; he did not seek medical attention. his new injury involved the knee. the other player had sustained a sprain in the preceding month for which he received medical treatment. the new injury sustained was a dislocation of the patella. both players were being tackled when the new injuries occurred. discussion more injuries were sustained at the beginning of the season. an increase in the players’ fitness levels could explain the decline in the occurrence of injuries towards the end of the season. kofotolis et al. 6 reported that the incidence of injuries was significantly higher during the first 2 months of the season compared with the last month. players who were involved in more intense contact situations, e.g. midfielders and defenders, were more prone to injury than players in other positions on the field. the correlation between a player’s position and the occurrence of injuries is supported by findings reported in the literature, stating that players in contact positions, such as defenders, 2,6 were more prone to injury. the observation that most of the injuries were of grade 1 severity and no injury exceeded grade 3 severity, could be ascribed to the relative lack of impact and low-impact nature of the game, i.e. no scrums, rucks (loose scrums) and mauls as in rugby. azubuike and okojie 2 also reported that most soccer injuries were of a moderate nature. on the other hand, compared with injuries sustained from running and racquet sports, soccer injuries were found to be more serious. 4 kofotolis et al. 6 reported that more than 60% of injuries were observed towards the end of each half of the game. in our study, however, similar rates of injury were observed in the first, third and fourth quarters of the game, where first-quarter injuries could possibly have been attributed to improper warm-up exercises, and fourth quarter injuries to player fatigue. because of the nature of the sport, it was not surprising that the two body areas most frequently affected by injury were the ankle (47%) and the knee (27%). in soccer there is also a low level of contact/impact, which could explain why most of the injuries were sprains (60%) and considered as minor injuries. this study confirmed that injuries sustained by soccer players mainly involve the lower extremity, and that less serious injuries occur owing to the low-impact nature of the sport. the researchers expected to find that players who had previously been injured and had not received medical attention would be more fig. 4. mechanism of play carried out when injury occurred. 3 7 3 2 0 1 2 3 4 5 6 7 8 dribbling being tackled tackling another player making a save number of injuries fig. 4. mechanism of play carried out when injury occurred. sajsm vol 21 no. 1 2009 � prone to injury than those without a history of injury. however, the results showed that this was not necessarily the case, as seen in the 2 injured players who had a history of previous injury. ideally, one should have considered all the games played by all the teams in the coca cola league, including practice sessions, warm-up exercises and matches. this was, however, not feasible owing to time, and financial and manpower constraints. for future studies of this nature, it is recommended that a larger research team conduct the investigation, and that a larger cohort of participants is included. furthermore, medical personnel should be available at all matches for sideline evaluation and confirmation of injuries sustained by players. acknowledgements the authors would like to thank mr m mohape, coach of the male first soccer team of the ufs, members of the ufs first soccer team playing in the coca cola league, who participated in this study, and ms daleen struwig, medical writer, faculty of health sciences, ufs, for technical and editorial preparation of the manuscript for publication. references 1. federation for international football associations (fifa). fifa big count 2006: 270 million people active in football (http://www.fifa. com/mm/document/fifafacts/bcoffsurv/bigcount.statspackage_7024.pdf (accessed 17 november 2008)). 2. azubuike os, okojie ho. epidemiology of soccer injuries in benin city, nigeria. br j sports med 2008; 23 october (epub ahead of print. http://www. ncbi.nlm.nih.gov/pubmed/18927169 (accessed 13 november 2008)). 3. centers for disease control and prevention (cdc). nonfatal sportsand recreation-related injuries treated in emergency departments – usa, july 2000 june 2001. mmwr 2000;51:736-740. 4. fong dt, man cy, yung ps, cheung sy, chan km. sport-related ankle injuries attending an accident and emergency department. injury 2008;39:1222-1227. 5. hägglund m, waldén m, ekstrand j. injuries among male and female elite football players. scand j med sci sports 2008; 13 october (epub ahead of print. http://www.ncbi.nlm.nih.gov/pubmed/18980604 (accessed 13 november 2008)). 6. kofotolis nd, kellis e, vlachopoulos sp. ankle sprain injuries and risk factors in amateur soccer players during a 2-year period. am j sports med 2007;35:458-466. 7. morgan be, oberlander ma. an examination of injuries in major soccer league. the inaugural season. am j sports med 2001;29:426-430. 8. yard ee, schroeder mj, fields sk, collins cl, comstock rd. the epidemiology of united states high school soccer injuries, 2005-2007. am j sports med 2008;36:1930-1937. 9. van mechelen w. the severity of sports injuries. sports med 1997;24:176180. � sajsm vol 21 no. 1 2009 the south african journal of sports medicine the editor the south african journal of sports medicine po box 115, newlands, 7725 tel: (021) 650-4558 fax: (021) 686-7530 e-mail: mike.lambert@uct.ac.za article submissions: www.sajsm.org.za plagiarism policy: www.sajsm.org.za/index.php/sajsm/about/editorialpolicies the views expressed in individual articles and advertising material are the personal views of the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent of the publishers. editor prof. mike lambert university of cape town editorial board dr kerith aginsky university of the witwatersrand dr theresa burgess university of cape town dr richard de villiers drs van wageningen and partners, somerset west dr lize havemann-nel north west university dr christa janse van rensburg university of pretoria dr louis holtzhausen university of the free state prof. frank marino charles sturt university, australia dr babette pluim royal netherlands lawn tennis association, the netherlands publisher health and medical publishing group 28 main road, rondebosch, 7700 private bag x1, pinelands, 7430 tel: (021) 681-7200 hmpg editor-in-chief janet seggie deputy editor bridget farham editorial systems manager melissa raemaekers scientific editor kerry gordon technical editors emma buchanan, paula van der bijl art director brent meder dtp/layout anelia du plessis, carl sampson production assistant neesha hassan head of publishing robert arendse head of sales and marketing diane smith | tel: (012) 481-2069 contents editorial 3 a phase of consolidation before moving forward again m lambert original research 4 common acute and chronic musculoskeletal injuries among female adolescent field hockey players in kwazulu-natal, south africa t j ellapen, k bowyer, h j van heerden 9 collagen gene interactions and endurance running performance k o’connell, m posthumus, m collins 15 steps that count! a feasibility study of a pedometer-based, healthpromotion intervention in an employed, south african population j d pillay, t l kolbe-alexander, k i proper, w van mechelen, e v lambert 20 micro-oscillations in positive and negative affect during competitive laboratory cycle time trials – a preliminary study c rhoden, j west, a renfree, m corbett, a st clair gibson 26 the prevalence of self-reported neck pain in rugby union players in gauteng province e d watson, r-l hodge, m gekis 32 cpd questionnaire volume 26 | number 1 | april 2014 mailto:mike.lambert@uct.ac.za http://www.sajsm.org.za http://www.sajsm.org.za/index.php/sajsm/about/editorialpolicies original research 1 sajsm vol. 29 2017 the prevalence, risk factors predicting injury and the severity of injuries sustained during competition in professional mixed martial arts in africa s venter,1 msc; d c janse van rensburg,1 md; l fletcher,3 phd; c c grant,1 phd 1section sports medicine, faculty of health science, university of pretoria, pretoria, south africa 2institute for sports research, university of pretoria, pretoria, south africa 3department of statistics, faculty of natural & agricultural sciences, university of pretoria, pretoria, south africa corresponding author: s venter (drventer@yahoo.com) mixed martial arts (mma) is a full-contact, unarmed combat sport that allows striking and grappling techniques.[1] this includes karate, jeet-kune-do, kung-fu, muay-thai, boxing, kickboxing, judo, taekwando, ninjitsu, wrestling, jiu-jitsu and brazilian jiu jitsu (bjj). mma has evolved into a sport represented by numerous bodies around the world.[2] the ultimate fighting championship (ufc) based in america is regarded as the world dominant mma platform. in 1996, arizona senator john mccain described mma as “human cockfighting”, and sent letters to the governors of all fifty usa states asking them to ban the event. thirty-six states banned the “no-holds-barred” fighting. in response to all the criticism, the ufc redesigned its rules to remove the unpalatable elements of the fights, while retaining the core elements of striking and grappling. this lead to the creation and implementation of the new jersey state athletic control board’s unified rules[3] in november 2000, which are obeyed in most professional regulated mma competitions around the world. these rules, aimed at increasing the safety of competitors, helped promote the mainstream acceptance of the sport. mma in africa is regulated by the international mixed martial arts federation (immaf) [4], and the unified rules apply to efc africa. mma competitions have male and female divisions, each with their own weight divisions. competitors wear compulsory safety gear (4 ounce or 113.4g gloves, mouth guard and groin protector). fights take place in a three m2 hexagon/ring fenced in area. this area has a 2.5 cm padded floor and two entrances. all exposed metal is covered. competitors have to pass a basic medical examination and screening tests for human immunodeficiency virus (hiv) and hepatitis. normally fights consist of three 5-minute rounds with a one-minute rest period between rounds. however, championship bouts consist of five 5-minute rounds. a qualified referee oversees the mma fight and can use his/her discretion to stop the fight. during the fight, all rules need to be adhered to and if disobeyed, may result in disqualification. the rules ban headbutting, eye-gouging, fish-hooking, groin attacks, fingers into orifices/lacerations, small joint manipulation, 90 degree elbows, blows to the back of the head, blows to the kidney with the heel, throat strikes and grabbing of the trachea/clavicle, kicking/kneeing the head of a grounded opponent, stomping a grounded opponent, and spiking an opponent to the canvas on his head/neck. a fighter can win a match in different ways: submission (verbal/tap out); knockout (ko); technical knockout (tko); or decision via scorecards. the fight can also be declared a draw, disqualification, forfeit, technical draw/decision or no contest. ten competitions are hosted in south africa every year by the efc. more than 300 athletes have competed at efc africa since its inception in 2009. despite the popularity of mma in africa there is no information about the prevalence, severity and risk background: professional mixed martial arts (mma) has gained international popularity. no african-based studies have reported the prevalence or severity of injuries, risk factors associated with injuries or return-to-play (rtp) time. objectives: to determine the prevalence of injuries and associated risk factors, as well as severity of injuries sustained by professional male mma athletes competing at the extreme fighting championships africa (efc africa) from 2010 to 2014. methods: permission to do the study and the medical records of all professional events (2010 – 2014) were obtained from efc africa. data were obtained from 173 male competitors aged 18 to 44 years, who had participated in 300 professional mma fights. results from this prospective cohort study were compared to a similar study done in the united states of america (usa). an injury was defined as any damage to an athlete’s body that needed the attention of the ringside physician. statistical analyses included descriptive statistics and a stepwise logistic regression. odds of an injury were predicted with six independent variables: fight outcome, age, weight division, number of fights, injuries in the preceding fight and years of fighter experience. results: head, face and neck injuries were most common (22%), followed by traumatic brain injuries (knockouts) (6%). losing a fight was a significant predictor of injury when using the stepwise logistic regression model (p=0.040). the odds ratio indicated that a preceding fight injury almost doubled the risk of injury in the following fight (or 1.91; p= 0.163). traumatic brain injuries (tbis) in this study of african-based competitions (6%) were substantially higher than reported in the american study (1.8%). conclusion: head, neck and face injuries are common in african fighters. the high rate of tbis in african competition compared to the usa study is concerning. this could reflect superior refereeing in the usa group, as fights may be ended sooner by stoppage. further investigation of injury trends and preventative measures should be studied to reduce the incidence of injuries during african competitions. keywords: mixed martial arts, concussion; return-to-play s afr j sports med 2017;29:1-5. doi: 10.17159/2078-516x/2017/v29i0a1471 mailto:drventer@yahoo.com http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1471 original research sajsm vol. 29 2017 2 factors associated with injuries during competition. therefore the aim of this study was to determine the prevalence and severity of injuries, as well as risk factors associated with sustaining injuries in professional mma competitions in africa. methods study design a prospective cohort study was designed using medical records as documented by an accredited ringside physician. the research ethics committee of the university of pretoria approved the study after permission from the custodian of the data, efc africa, was confirmed. participants and demographics all injuries sustained by athletes competing at efc africa events from 5 august 2010 to 14 june 2014 were included in the study (n = 300 fights or 600 fight exposures). competitors consisted of 173 male athletes between the ages of 18 and 44 years. only male athletes were included in this study as professional female mma in africa was only introduced in 2015. medical data collection medical records were obtained from the event medical support team with the permission of the custodian of the data; efc africa. an accredited ringside physician recorded these records immediately after the fight, reporting all injuries sustained according to anatomic location, type of injury and injury severity. the anonymity of the injured fighter was maintained and the average return-to-play (rtp) time after injury was considered an indicator of the severity of the injury. data obtained included the date of the fight, total number of fights, total injuries (damage to an athlete’s body that needed the attention of the ringside physician), outcome of the fight, competitor’s age at the date of the fight, weight divisions, years of experience, injuries sustained in the previous fights, injuries sustained in the current fight by anatomic location and severity, time between fights and time off until rtp. data were compared to a study conducted by ngai[5], reviewing injury trends in 635 professional usa mma fights from 20022007. statistical analysis the statistical analysis included descriptive statistics and a stepwise logistic regression model using ibm spss statistics 22. odds of an injury were predicted with the following independent variables: fight outcome, age, weight division, number of fights, injuries in the preceding fight and years of fighter experience. these results were also compared to a similar study by ngai as previously mentioned. this study also used the term “fight exposures” as used in the ngai study, indicating that two athletes are exposed to injury per fight. similarly, the injury odds ratios were calculated using logistic regression including match outcome, weight, age and fight experience, during a pair-matched case-control study design (n=464). cases were also defined as fighters who sustained an injury/received medical attention during the matches, and controls were defined as fighters who were uninjured. results general table 1 summarises fight exposures, the total number of injuries and total number of traumatic brain injuries (tbis). of the 300 fights (600 exposures), 295 fights ended with a ‘win’ result for one fighter and a ‘loss’ result for the other fighter. two fights were cancelled before taking place, two fights ended in draws and one fight was deemed a ‘no contest’. among the 600 professional mma fight exposures included in the study, 222 total injuries were reported. the injury rate is thus 37 per 100 fight exposures. percentage of injuries according to anatomic location table 2 reflects the total prevalence of injuries in the present study by anatomic location and average rtp following specific injuries. injuries to the head, face and neck were the most common (22%), followed by tbis due to knockouts (6%), upper limb injuries (4%), lower limb injuries (3%) and injuries to the torso/back/ribs (2%). one death due to intra-cerebral haemorrhage resulted from an mma fight during the study period. fifteen fractures were reported (table 3). the most common fractures sustained were rib fractures (5), followed by metacarpal (4) and metatarsal fractures (2). only two table 1. fight exposures, total injuries and total traumatic brain injuries (tbis) year number of fight exposures# injuries n (%) tbis n (%) overall 600 222 (37) 50 (8) 2010* 70 21 (27) 7 (10) 2011 120 47 (34) 13 (11) 2012 154 57 (34) 11 (7) 2013 180 60 (31) 13 (7) 2014** 76 37 (49) 6 (8) n, number of participants; tbis, traumatic brain injuries. #two athletes are exposed to injury per fight. *as from 5 august 2010. **as at 14 june 2014. . table 2. prevalence of injuries and return-to-play (rtp) body region injuries n (%) average rtp (95% ci) upper limb 25 (4) 3.7 weeks (2.8;4.4) lower limb 21 (3) 7.7 weeks (0.2;15.2) head/face/neck 130 (22) 2.2 weeks (2.0;2.3) tbis (ko) 34 (6) *4 weeks torso/back/rib/groin 12 (2) 3.5 weeks (2.2;4.8) total number of injuries 222 (37) n, number of participants; tbis, traumatic brain injuries; ko, knock out *hypoxic brain injuries due to chokes (n=87; 14.5%) were not included in the statistical analyses of the data, as this isn’t considered an injury per se, but rather a method of victory. fighters usually ‘tap out’ and thus submit to their opponents before any physical damage occurs. . original research 3 sajsm vol. 29 2017 dislocations occurred during the study period and both involved the shoulder joint. injuries to the face included 16 episodes of epistaxis, and five auricular hematomas. returntoplay (rtp) times lower limb injuries were responsible for the longest time off play. the average rtp after injury was 7.7 weeks. lower limb injuries included anterior cruciate ligament (acl) and posterior cruciate ligament (pcl) ruptures, for which the average rtp is one year. two of these injuries were recorded during the study period, thus contributing to the increased rtp average. rtp averages 3.7 weeks following upper limb injury, with metacarpal fractures contributing mostly to the prolonged recovery time. a four-week period is the average time needed to recover from tbis/hypoxia. this follows the 30 day knockout rule. injury to the torso/back/rib/groin requires 3.5 weeks until rtp (rib fractures and soft tissue injuries). following a head/face/neck injury, rtp averages 2.2 weeks. the most regular time lapse between all fight exposures, whether athletes were injured or uninjured, was three months (84%), but may vary between 22 days and four years. the three month time lapse most frequently represents the time fighters take to rest after preparing for a fight and subsequently competing. certain athletes compete again after a shorter time lapse, depending on their conditioning and motivation for competing (financial gain, title contention, etc.). logistic regression: injury prediction logistic regression models were used to compare injured athletes to non-injured athletes. (table 4). the odds ratio of an injury were modelled using four independent variables: the outcome of the fight, the age of the athlete, the weight division and the number of fights. the results of this logistic regression were compared to a study conducted by ngai[5] in the usa, using the same predictors. three models were constructed: model 1 included the above-mentioned four predictors; in model 2, two more predictors were added, i.e. injuries sustained in the preceding fight and the total years of experience of each fighter. for model 3 a stepwise logistic regression was performed to identify possible predictors of injury (with a stepwise procedure, only significant predictors are included in the model). in sa model 1 no single predictor was found to be significant for predicting an injury, although there is moderate to strong quality evidence that losing a fight is a predictor (p=0.052), controlling for age, weight and number of previous fights. the additional two predictors in sa model 2 (years of experience and injury in the previous fight) were also not significant. however, losing a fight was a significant predictor of injury when controlling for the other five explanatory variables. using stepwise logistic regression (sa model 3), losing a fight was again a significant predictor of injury in that fight (p=0.041). the odds ratio (or) indicated that losing the previous fight doubles the risk of injury (or 2.02). a preceding fight injury also more than doubles the risk of injury in the following fight (or 2.19; p= 0.060). discussion overall injury prevalence appears to be as high as 37% in the present study compared to only 24% in the usa study by ngai.[5] the total percentage of tbis in the african-based competitions (6%) is also substantially higher than in the usa-based competitions (2%). losing a fight was a significant predictor of injury when employing a stepwise logistic regression model (p=0.041), doubling the risk of sustaining an injury in the following fight (or 2.02). fighters who sustained an injury in the preceding fight also more than doubled the risk of sustaining an injury in the following fight (or 2.185, p=0.06) (table 4). the total percentage of injuries averaged 37% between 2010 and 2014 (table 1). a substantial increase in the amount of tbis was recorded in 2011. possible causes could include table 3. injury prevalence by anatomic location (excluding brain injuries) body region soft tissue injury fracture dislocation ligament rupture hand 8 4 elbow 5 1 1 shoulder 3 1 2 foot 8 2 ankle 4 knee 5 2 head/ face/neck 128 2 torso/ back/rib 5 5 groin 2 total 168 15 2 3 188 table 4. logistic regression results comparison of injured vs. non-injured athletes odds ratio (or) (p-value) sa model 1 sa model 2 sa model 3 losing fighter 2.04 (0.052)** 2.16 (0.040)* 2.02 (0.041)* age 1.05 (0.313) 1.03 (0.515) weight¶ (0.206) (0.212) number of fights 1.09 (0.218) 1.05 (0.545) years of experience 1.01 (0.788) injured in previous fight 1.92 (0.163) 2.19 (0.060)** sa, south africa *significant at the 5% level of significance. **significant at the 10% level of significance. ¶ weight was entered in the model as a categorical variable with six different weight divisions. original research sajsm vol. 29 2017 4 competitor-dependent variables such as inexperience, poor weight-cutting techniques and injuries sustained during training; unrealistic rtp periods; poor refereeing or application of rules and safety measures; and poor prefight medical screening. there was also a dramatic increase in the percentage of injuries sustained during 2014 (table 1). this may be an indication of superior post-fight medical assessment of fighters by experienced sports physicians. professional mma fighters have a three times higher injury rate than amateur mma fighters.[6] it is the author’s opinion that this could be ascribed to a higher level of competition, or it could also be due to the lack of protective gear and the legality of knee and elbow strikes to standing/grounded opponents in the professional fights. further studies are advised in this regard. mma and concussion the ngai study[5] reports that 36% of all injuries in mma occur to the head/neck/face region which is higher than the 22% rate reported in the sa study. approximately 7% of fights end in a ko in the usa study as compared to 6% in the sa study. scoggin et al.[6] found that 20% of injuries sustained during mma bouts were concussions resulting in brief (<15seconds) loss of consciousness and/or retrograde amnesia. head-impact (also implying concussion) in mma training and competition is common. head injuries occur in other contact sports, and in a multitude of non-contact sports.[7] boxing carries a high rate of head injuries with the highest rate of sport-related mortality due to tbis.[8] a recent article, however, claims that cyclists have the highest rate of sportsrelated tbis.[9] other contact sports in which tbis frequently occur include ice-hockey, muay-thai, kick-boxing and rugby. non-contact sports in which athletes sustain regular concussions include soccer, basketball, skiing, lacrosse, baseball, basketball, snowboarding, skateboarding and motocross. many head injuries in athletes are the result of improper playing techniques and this can be reduced in african athletes through the teaching of proper skills and enforcing safety promoting rules.[10] safety gear and tbis the use of protective headgear has remained a controversial topic of discussion. the main viewpoints regarding the use of headgear are, firstly, the ability to decrease the impact of strikes to the head, and thereby limiting the incidence of tbis. the international boxing association (aiba) banned amateur boxers from wearing headgear in a bid to reduce the incidence of concussion. this decision supports the second point of view, following an internal study by wang[11], showing that a lack of headgear actually reduces the risk of concussion. researchers agree that while headgear can help to avert other serious head and facial injuries, there was no scientific evidence proving that it contributes to the prevention of concussion, and, paradoxically, it may even encourage fighters to take greater risks. repeated, sub-concussive hits to the head damage the blood-brain-barrier and are also linked to chronic traumatic encephalopathy later in life.[12] headgear can obscure peripheral vision, making it harder to see when a blow is aimed at the side of the head. the use and size of gloves regarding mma and boxingrelated head injuries are also controversial. strikes to the head were less common in the bare-knuckle era because of the risk of hand injuries. gloves reduce the incidence of lacerations to the face, but research has stated that gloves do not reduce tbis and may even increase the incidence.[13] this is explained by considering head acceleration-deceleration as the mechanism of injury leading to a concussion. large gloves force fighters to deliver an increased number of more forceful strikes to the head (higher striking rate and acceleration) in order to achieve a ko. rtp a much disputed area of combat sport is the return of fighters to competition after injury.[14] the most debated issue is the time lapse during this convalescent period and how it differs for specific injuries (head injuries, fractures, dislocations, etc.). concussions are often missed, while their detection and management are imperative, as mismanagement of this syndrome can lead to persistent/chronic post-concussion syndrome or diffuse cerebral swelling.[15] in keeping with international standards, efc africa requires fighters to undergo a pre-fight uncontrasted computerised tomography (ct) brain scan. no fighters are allowed to return to competition after suffering a ko loss in a fight within 30 days (the 30-day knockout rule). the average rtp after injury varies from 2.2 weeks to one year, depending on the type, anatomic location, and severity of injury. the 30-day knockout rule is a mandatory medical suspension that applies to all athletes who suffered tbis during competition. unfortunately, it is difficult to assess athletes for tbis sustained during training and the onus of rtp following such injuries is largely placed on the athletes themselves and their coaches. choke submissions as a method of victory occurred in 10% of mma fights included in this study. these manoeuvres are reported separately, as the mechanism involved in causing loss of consciousness while being choked differs from that of a ko. choke submissions induce temporary brain hypoxia, whereas kos are related to acceleration-deceleration tbis. thus choke submissions cannot be regarded as concussions. joint submissions contributed to a win result in 3% of cases, and injuries sustained due to these manoeuvres are subsequently reported as upper or lower limb injuries. injuries although tbis are the most feared injuries in mma, other less serious injuries occur regularly. these include auricular haematomas, orofacial, head, limb, torso and groin injuries. the submission-grappling component has increased the incidence of strains and dislocations to the shoulder, elbow, wrist, knee and ankle joints respectively. the striking component is largely responsible for injuries to the face, head, ribs, long bones and soft tissue of the extremities. conclusion the pool of professional mma athletes in africa is small (161 signed athletes) compared to the thousands of athletes original research 5 sajsm vol. 29 2017 competing in the usa. one professional mma event is held in sa every month, while several events take place in the usa on a weekly basis. this study is the first comprehensive analysis of injuries sustained in professional mma competition in africa to date. further studies are advised to record injury trends, including the risk factors associated with injuries and the severity of injuries in professional mma. the concussion rate during training and the subsequent rtp should be studied to minimise incidents of exposing concussed athletes to competition too early. pre-fight magnetic resonance imaging (mri) studies, although expensive, could aid in the detection of training-related concussions. this study provides the most comprehensive analysis of ringside physician-collected data on professional male mma fighters in africa. no study has included the possible predictors of injury or the rtp time, making this study a valuable aid to fighter safety for fighters, physicians, promoters and referees. only one study has reviewed the epidemiology of injuries in mma, and this included amateur and professional athletes of both genders. [6] although much has been done to improve fighter safety by the introduction of the unified rules of conduct [3], mma still remains a contact sport with limited control over the incidence of injuries. this study recorded the prevalence of injuries, the risk factors associated with sustaining an injury and the severity of injuries during competition in africa. the value of this study this study has highlighted the following: • the overall prevalence of injuries during mma competition in africa from 2010-2014 was as high as 37%; • the incidence of life-and/or limb-threatening injuries appears higher when compared to the usa study; • risk factors for sustaining an injury in competitive professional african athletes include an injury in the previous fight and losing the current fight; • tbis in the african based competition study (6%) was substantially higher than the usa study by ngai[5] (1.8%). thus this study contributes to enhancing overall fighter safety by creating awareness among sanctioning bodies, trainers, referees, sports physicians and fighters:  losing a fight vs. injury correlation: a focus on mental toughness and additional care should be given to losing fighters;  rtp should not be considered before full recovery;  fights may be ended sooner due to referee stoppage. further studies are needed to aid in maximising the safety of mma fighters by educating the sanctioning bodies, trainers, referees, sports physicians and fighters. references 1. little jr, wong cf. ultimate martial arts encyclopaedia.1st ed. mcgraw-hill 2000:3-32. 2. garcia sr, malcolm d. decivilizing, civilizing or informalizing? the international development of mixed martial arts. int rev soc sport 2010;45(1): 39-58. http://doi.org/10.1177/1012690209352392 3. new jersey state athletic control board. mixed martial arts unified rules of conduct. http://www.state.nj.us/lps/sacb/docs/martial.html (accessed 25 march 2015). 4. international mixed martial arts federation. http://www.immaf.org 5. ngai km, levy f, hsu eb. injury trends in sanctioned mixed martial arts competition: a 5-year review from 2002 to 2007. br j sports med 2008;42(8):686-689. [https://doi.org/10.1136/bjsm.2007.044891] [pmid: 18308883] 6. scoggin jf 3rd, brusovanik g, pi m, et al. assessment on injuries sustained in mixed martial arts competition. am j orthop (belle mead nj) 2010;39(5):247-251. https://www.ncbi.nlm.nih.gov/m/pubmed/20567743/ [pmid: 20567743] 7. cantu rc. head injuries in sport. br j sports med 1996;30(4):289-296. http://doi.org/10.1136/bjsm.30.4.289 8. baird lc, newman cb, volk h, et al. mortality resulting from head injury in professional boxing: case report. neurosurgery 2010;67(2):e519-520. [https://doi.org/10.1227/neu.0b013e3181e5e2cd] [pmid: 20644386] 9. hinck m, sims i. jamaica hospital warns: bicyclists suffer more brain injuries than football players. http://medisyshealth.org/publicaffairs/pressrelease/articlebyl d.php?id=73 (accessed 23 january 2015). 10. jordan bd.the clinical spectrum of sport-related traumatic brain injury. nat rev neurol 2013;9(4):222-30. [https://doi.org/10.1038/nrneurol.2013.33] [pmid:23478462] 11. wang ss. boxing group bans headgear to reduce concussions. the wall street journal. 2013. http://www.wsj.com.news/articles/sb1000142412788732339330 4578360250659207918 (accessed 10 may 2016). 12. gavett be, stern ra, mckee ac. chronic traumatic encephalopathy: a potential late effect of sport-related concussive and sub-concussive head trauma. clin sports med 2011;30(1):179-188. https://doi.org/10.1016/j.csm.2010.09.007 13. british medical association. boxing debate. may 2002. http://bma.org.uk/ap.nsf/content/boxing+debate+ (accessed 10 may 2016). 14. sedney cl, orphanos j, bailes je. when to consider retiring an athlete after sports-related concussion. clin sports med 2011;30(1):189-200. available at [https://doi.org/10.1016/j.csm.2010.08.005] [pmid:21074092] 15. harmon kg, drezner ja, gammons m, et al. american medical society for sports medicine position statement: concussion in sport. br j sports med 2013; 47(1):15-26. http://doi.org/10.1136/bjsports-2012-09194 http://doi.org/10.1177/1012690209352392 http://www.state.nj.us/lps/sacb/docs/martial.html http://www.immaf.org/ https://doi.org/10.1136/bjsm.2007.044891 https://www.ncbi.nlm.nih.gov/m/pubmed/20567743/ http://doi.org/10.1136/bjsm.30.4.289 https://doi.org/10.1227/neu.0b013e3181e5e2cd http://medisyshealth.org/publicaffairs/pressrelease/articlebyld.php?id=73 http://medisyshealth.org/publicaffairs/pressrelease/articlebyld.php?id=73 https://doi.org/10.1038/nrneurol.2013.33 http://www.wsj.com.news/articles/sb10001424127887323393304578360250659207918 http://www.wsj.com.news/articles/sb10001424127887323393304578360250659207918 https://doi.org/10.1016/j.csm.2010.09.007 http://bma.org.uk/ap.nsf/content/boxing+debate+ https://doi.org/10.1016/j.csm.2010.08.005 http://doi.org/10.1136/bjsports-2012-09194 introduction the world anti-doping agency (wada) is the leader in the fight against doping in sport. this agency publishes a list of prohibited substances, which is updated on an annual basis.1 the south african institute for drug-free sport (saids) is one of the many signatories that complies with wada’s prohibited list, and also publishes an annual prohibited list based on south african brand names.2 doping is regarded as a form of cheating where athletes use substances that are on these prohibited lists, predominantly for gaining an edge over their competitors.3 an alternative to doping can be nutritional substance use, which helps to improve the health and performance of active adolescent athletes. despite strong efforts in attempting to eliminate doping in sport, the use of drugs and prohibited substances to boost performance is common among athletes.3 south african adolescent sport seems to have changed dramatically, as it appears that there are greater pressures placed on adolescent athletes to excel in sport and some are using performance-enhancing substances (pes) to cope with the demands placed on them.4-6 the problem is that some of the pes are listed as prohibited, and adolescent athletes might be tempted to use these because the pressures and stresses facing them may be too immense to resist.1 just as the competitive nature of professional sports has led to athletes doing whatever they can to give themselves an edge in competition, and sometimes placing their well-being at risk, it seems to have also trickled down into youth sports. furthermore, many of the adolescent athletes who do not believe they are successful at a competitive level may choose to take prohibited pes.7 additionally, in spite of the view that the use of doping remains ‘fundamentally contrary to the spirit of sport’,8 athletes are using prohibited pes in sport. some athletes are advocating that these substances be legitimately used for the enhancement of performance best in competition.9,10 these banned products may enable them to improve their athletic performance, help with recovery from hard physical training and improve self-image in the short term; however, in the long run there may be negative costs to their well-being and general health.7 therefore, the purpose of this study was to investigate the attitudes and perceptions of male adolescent competitive athletes from johannesburg boys high schools towards pes use in sport. original research article attitudes and perceptions towards performance enhancing substance use in johannesburg boys high school sport abstract introduction. the environment of youth sport in south africa has transformed considerably, where adolescent athletes are faced with more pressure from coaches, peers and parents to perform well. some of the athletes are using nutritional supplements or prohibited means such as doping to cope with these pressures and gain an edge in competition. objectives. in view of the lack of literature investigating the use of doping in south african adolescents, the objective of the study was to determine the attitudes and perceptions of male adolescent athletes regarding performance-enhancing substance (pes) use. methods. the design of the study was cross-sectional and used a self-administered questionnaire. a sample of participants was obtained from male adolescent high school athletes involved in 1st and 2nd high school sports teams in johannesburg boys high schools. participants were invited to volunteer to participate in the study. questionnaires were completed under conditions that were similar to an examination situation. demographic data were analysed using descriptive statistics. results. the majority (91%) of the athletes indicated a belief that the number of athletes using pes in sport is increasing. eightyfour per cent of them felt that there was pressure placed on them to use pes to win. only 55% of respondents believed that doping tests would prohibit the use of banned substances and 91% did not believe that the sale of prohibited substances should be banned. the majority (88%) believed there is a need for further education. correspondence: philippe gradidge centre for exercise science and sports medicine university of the witwatersrand po box 85484 2029 emmarentia tel: +27 11 717 3372 fax: +27 86 609 2017 e-mail: philippe.gradidge@wits.ac.za philippe gradidge (bspsc (hons) biokinetics) yoga coopoo (dphil, facsm) demitri constantinou (mb bch, bsc med hons, ffims) centre for exercise science and sports medicine, faculty of health sciences, university of the witwatersrand, johannesburg 32 sajsm vol 22 no. 2 2010 conclusion. although there is enormous pressure on high school boys to use pes, their knowledge is lacking, especially with regard to doping in sport. sajsm vol 22 no. 2 2010 33 methods the study used a cross-sectional method design with a self-administered questionnaire, which had been adapted from a study that investigated doping in elite south african athletes.11 the reliability and validity of the adapted questionnaire was tested in a pilot study, and was found to be 83% reliable. further validation of the questionnaire was provided by professionals practising in the fields of biokinetics, exercise science and sports medicine. the questionnaire was formulated to elicit responses on pes and nutritional supplements used in order to improve performance. the participants’ attitudes and perceptions regarding pes use were solicited, such as beliefs about pes use in sport and whether education on doping was needed. a sample of participants was attained from male adolescent high school athletes, aged between 15 and 18 years, involved in 1st and 2nd team high school sports from public and private johannesburg boys high schools. the provincial department of education granted permission to conduct the study and ethical clearance (m060953) was obtained from the university of the witwatersrand human research ethics committee. arrangements were made to conduct the study on a date and time that was convenient for the high schools that gave consent to participate. those participants who volunteered to participate provided minor assent and parental informed consent. they completed the questionnaire under conditions where participants were not allowed to communicate with each other. the participants were also given the opportunity to ask questions pertaining to the content and completion of the questionnaire. questionnaires were handed in to the researcher immediately after completion. the collected data were then group-analysed using the epi info (tm) 3.5.1 statistical software package. data were descriptive and involved summary statistics displaying frequencies and percentages. results the responses of the participants were coded and missing values were not included in the analysis because it was not possible to determine what the participants would have answered in these cases. some of the participants did not answer all questions and in most cases multiple responses were given to certain questions where more than one option could have been chosen. these multiple responses were taken into account when analysing the data. figure 2: main high school sport participation and establishing whether pes use is believed to be on the increase 5 1 1 1 1 37 5 5 3 14 5 6 4 5 1 3 1 2 0 5 10 15 20 25 30 35 40 do think that pes use in sport is increasing? no (%) yes (%) fig. 1. main high school sport participation and establishing whether pes use is believed to be on the increase (n=100) table i. prevalence of substances used and reasons for using pes (n=100) prevalence of pes use % yes 30 no 64 non-response 6 common prohibited substances used anabolic androgenic steroids (n=100) 4 growth hormone (n=100) 5 adrenaline /ephedrine (n=100) 4 insulin (n=100) 2 common non-prohibited supplements used caffeine supplementation (n=28) 57 creatine supplementation (n=84) 32 carbohydrates supplementation (n=90) 54 protein supplementation (n=88) 61 vitamin supplementation (n=88) 61 reasons for using pes assists me in coping with the stresses of sport (n=24) 29 helps to improve the way i perform in sport (n=25) 68 helps to reduce food craving in order to decrease my body weight (n=25) 32 i feel afraid of being dropped from the team (n=24) 21 i will have a better chance of making the team (n=25) 28 figure 1: general attitudes and perceptions towards pes use in sport (n=100) 9 16 45 28 47 62 84 91 81 91 84 55 72 53 48 16 9 19 do you feel that the use of pes in sport is rising? (n=100) do you believe there is pressure placed on high school athletes to use substances in sport? (n=97) do you feel that doping tests will prevent the use of substances in sport? (n=95) are you aware of any substances that are prohibited by the world anti-doping agency? (n=96) are you aware of the punishment for using prohibited substances in sport? (n=97) do you believe that more doping tests to be carried out? (n=94) do you feel that stricter punishments should be placed on athletes caught for doping? (n=94) should the sale of prohibited substances be banned? (n=94) do you think that more education on doping should be provided? (n=94) 0 20 40 60 80 100 yes (%) no (%) fig. 2. general attitudes and perceptions towards pes use in sport (n=100). demographic data of the 100 (81% response rate) competitive male adolescent athletes investigated, most were 17 18 years old (78%), while a minority were 15 16 years old (22%). they were from grades 10 (11%), 11 (67%) and 12 (22%). the majority of these participants (42%) played rugby (fig. 1). prevalence of substance use a number of the participants (30%) indicated using pes for enhancement of performance (table i). table i displays the prevalence of substances utilised for performance enhancement and the rationale participants had for using them. the majority of these athletes (68%) indicated that they used pes to have a better performance output in sport. general attitudes and perceptions towards pes use the responses on the participants’ general attitudes and perceptions towards doping are shown in fig. 2. most of the participants (91%) felt that pes usage in sport was on the increase. only 55% of them believed that testing for substance abuse would serve as a deterrent. over half of the participants (53%) were aware of the punishment that would be meted out for substance abuse, and 72% of them acknowledged that they knew of substances that were prohibited by wada. more specific attitudes towards pes use the adolescent athletes were asked to respond to twelve statements regarding their attitudes and perceptions towards the use of pes in sport. fig. 3 illustrates specific attitudes and perceptions towards doping in sport. participants’ answers to this section were analysed and calculated according to the total amount of responses per statement. thirty-five per cent of the participants agreed that prohibited substances were being used in their sports, and 30% agreed that there were several athletes making use of substances to increase their performance. sixty one per cent of the participants agreed that pes use in sport is unethical. sources of information for performance-enhancing substance use fig. 4 displays where the athletes obtained their information on pes usage. multiple responses were given in this section, thus the data were calculated by taking into account the number of individual responses per question. the highest ranking source of information on pes usage was the internet (74%), followed by magazines (72%), from a friend (66%), the coaching staff (66%), and parents (40%). some of the other mentioned sources of information on pes use in sport were from personal trainers (33%), information brochures (31%), newspapers (31%), the pharmacist (24%), and 23% indicated that they attained information from the television and their school. discussion the olympic charter’s goal of ‘friendship, solidarity and fair play’12 in sport still needs to become a reality, and should become a core pillar in the fight against doping in sport. using prohibited substances in sport is unethical and unfortunately the adolescent athletes using them may be doing so at the cost of their well-being and physiological development. even though most participants agreed that doping was cheating, they also reported immense pressure to perform and would perhaps turn to pes as a coping mechanism or performance advantage. it is for this reason that the anti-doping struggle in adolescent sport should not be taken without due consideration. adolescent athletes who have the potential to be successful in sport appear to be required to give maximum effort throughout the whole high school sporting season and this may be too stressful for them. parents, coaching staff and friends may sometimes place unrealistic demands on individuals and this could indirectly tempt or even encourage the use of prohibited pes in sport in some adolescent athletes.3,13 it may be beneficial for all those involved in high school sport, such as parents/guardians, coaching staff, teachers and the athletes, to be taught that losing or coming second or third is acceptable. in reality, even the elite and professional athletes have times when they do not win or days when performance is not at a peak level. hence, this approach could enable adolescent athletes to learn that fair game play and honest interaction with opponents are more essential than winning all the time.14 the results indicate that 4% of the participants are using anabolic androgenic steroids. these athletes may have used this banned substance in spite of the well-known harmful side-effects.15-17 if this pattern continues, adolescent sport can evolve into a win-at-all-costs phenomenon, where doing whatever it takes to excel in competition may become routine practice in some athletes. with the evolution of new pes products being engineered and sold on the black market, the adolescent athletes using them on a regular basis could be bearing the burden of utilising unknown substances which may have harmful and irreversible side-effects. some of these potential negative effects could include addictive and antisocial behaviour, as well as increased risk of heart disease.3,13 these side-effects may 34 sajsm vol 22 no. 2 2010 figure 3. specific attitudes and perceptions of high school learners towards doping in sport (n=100) 23 46 27 31 47 27 13 23.7 10 23 12 32 35 42 30 38 37 15 37 37.6 12 16 25 29 28 5 30 19 8 45 18 30.1 22 42 31 21 14 7 13 12 7 14 32 8.6 56 19 32 18 there is a problem of prohibited substance use in my sport/s. (n=96) sport organizations should offer educational programmes for athletes on the use of substances in sport. (n=96) there are too many athletes using substances in my sport to enhance their athletic performance. (n=96) the prohibited use of substances by athletes has not been reported on enough in the media. (n=94) the use of pes and supplements has risen in the last five years. (n=95) i would never consider using pes. (n=94) i am sometimes tempted to use pes. (n=93) many of my friends think it is acceptable to use pes. (n=93) if i don’t take pes, i will not be able to succeed because everyone else does. (n=94) i think it is always wrong to use pes. (n=93) i think athletes who want to succeed have to use pes sometimes. (n=94) i don’t think it is fair to use pes. (n=94) 0 20 40 60 80 100 120 strongly agree (%) agree (%) disagree (%) strongly disagree (%) fig. 3. specific attitudes and perceptions of high school learners towards doping in sport (n=100). sajsm vol 22 no. 2 2010 35 result in poor health and poor performance in the long term. although most of the athletes reported using pes for helping achieve optimal performance, most disagreed that taking pes was necessary to succeed (fig. 3). it is certainly acceptable that banned substances may induce a performance that is unattainable with ‘normal’ physiology or ethical means. nevertheless, it is also true that peak performance can be enhanced via ethical means without incurring the health risks and moral compromises of drug use. for instance, adolescent athletes can be taught how to improve performance through legitimate means, such as periodisation in training and sound nutrition.18 periodisation is a means of planning a training programme to ensure adequate recovery for the body, thus allowing the athlete to peak at the right times.18 nutritional supplement use is another way of helping active adolescents attain a healthy lifestyle and optimal performance in sport. these favourable and safe methods can give adolescent athletes a more ethical means of achieving their best in sport. moreover, the inclusion of psychology can act as a tool to improve adolescent athletes’ self-image and mastery in sport. in addition, more focus should be placed on educating adolescent athletes as well as others involved with them on the use of doping in sport and its adverse effects. the results show that the internet was the main source of information (74%) on pes use in sport. this result is possibly because the high schools involved in the study have access to this resource and its use as a means of finding out information is generally encouraged by teachers. the internet can sometimes be a good and reliable source of information, but the ability of the athletes to critically discern this is questionable. perhaps the skills of critically analysing information resources could be taught as part of the normal high school curriculum, thus equipping the athletes with the ability to make mature and ethical decisions regarding pes use. education is perhaps one of the key vehicles that can aid in discouraging the use of doping and prohibited pes in adolescent sport. even though a large number of participants in this study (72%) knew of some substances that were on wada’s list of prohibited substances, the findings of this study show that 46% strongly agreed and 42% agreed that education would provide a means of improving the awareness of prohibited pes, their adverse effects, and the rules regarding pes use in sport. these results confirm that the majority (88%) of the participants have a desire to know more about doping and feel that sporting bodies and other organisations should be providing this. doping may essentially tear down what is decent, ethical and good regarding adolescent sport. it may even corrode societal confidence and endanger the athletic adolescent population. educational drives should go beyond the elite, professional athlete and target those involved in recreational sports, where drug testing is not commonly seen.19 it is important to ensure that developing adolescent athletes are taught the fundamentals of fair play and good character while in the developmental stages of sports play. it would also be useful to include coaching staff, dieticians and other medical professionals who are involved with anti-doping strategies to aid and inform adolescent athletes on the use and abuse of drugs in sport, what factors lead to doping, and how to deal with these.20 it seems that a holistic approach to combating the problem of doping could provide a way of restoring the ethical values in sport. conclusion the knowledge regarding the use of doping in adolescent sport seems to be deficient, and the majority of the participants (88%) indicated that there was a need for more education on prohibited and non-prohibited pes use. there is great pressure placed on the athletes to succeed in high school sport, and some of these participants use pes to cope with the pressures. it appears that most adolescent athletes in this sample are not taking prohibited pes, as the non-prohibited substances were more commonly used. how ever, the need for educational intervention is still important to address the problem of doping in adolescent sport. it is recommended that these educational strategies be applicable and relevant to adolescent athletes, and perhaps be introduced at an early age to increase anti-doping attitude and develop a character of socially acceptable sporting behaviour. references 1. world anti-doping agency. http://www.wada-ama.org/en>. accessed 10 june 2010. 2. south african institute for drug-free sport. <http://drugfreesport.org.za/>. accessed 10 june 2010. 3. clisby l. drugs and the athlete. in: brukner p, khan k, eds. clinical sports medicine, 2nd ed. sydney: mcgraw-hill, 2005. 4. lambert mi, titlestad sd, schwellnus mp. prevalence of androgenicanabolic steroid use in adolescents in two regions of south africa. s afr med j 1998;88(7):316-330. 5. schwellnus mp, lambert mi, todd mp, juritz jm. androgenic anabolic steroid use in matric pupils. a survey of prevalence of use in the western cape. s afr med j 1992;82:154-158. 6. sports information and science agency. drug related issues in sport and awareness survey. pretoria: national department of sport and recreation, 1999. 7. mayo clinic staff. performance-enhancing drugs and your teen athlete. <http://www.mayoclinic.com:80/health/performance-enhancing-drugs/ sm00045>. accessed 16 march 2009. mayo foundation for medical education and research, 2009. 8. todd t. a history of the use of anabolic steroids in sport. in: berryman jw, park rj, eds. sport and exercise science essays in the history of sports medicine. urbana-chicago: university of illinois press, 1992. 9. koyser s, mauren a, miah a. viewpoint legalization of performance enhancing drugs. lancet 2005;366:21. 10. savulescu j, faddy b, clayton m. why we should allow performance enhancing drugs in sport. br j sports med 2004;38:666 -670. 11. coopoo y, jakoet i. substance abuse and knowledge thereof among elite south african athletes. s afr j sports med 2000;7(3):10-13. figure 4. sources of information for pes use (n=100) 26 28 34 40 67 67 69 71 76 77 81 84 84 90 91 74 72 66 60 33 33 31 29 24 23 19 16 16 10 9 the internet (n=93) magazines (n=88) friend (n=96) coach (n=94) parent (n=89) personal trainer (n=89) information brochures (n=80) newspapers (n=82) pharmacist (n=89) television and school (n=65) sibling (n=85) biokineticist (n=87) books (n=83) physician (n=87) journals (n=80) 0 20 40 60 80 100 yes (%) no (%) fig. 4. sources of information for pes use (n=100). 36 sajsm vol 22 no. 2 2010 12. international olympic committee. olympic charter. <http://multimedia. olympic.org/pdf/en_report_122.pdf>. accessed 16 march 2009. 13. british medical association. drugs in sport: the pressure to perform. london: bmj books, 2002. 14. gradidge p, constantinou d, coopoo y. the use of performance enhancing substances by high school boys. <http://web.wits.ac.za/newsroom/ newsitems/performanceenhancingsubstances.htm>. accessed 28 may 2010. 15. haller ca, benowitz nl. adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. n engl j med 2000;343:1833-1838. 16. gruber aj, pope hg. ephedrine abuse among 36 female weight lifters. am j addict 1998;7:256-261. 17. gill a. faster, higher stronger: confessions of an ephedrine junkie. the globe and mail 2002 march 9:l3. 18. lambert m. performance enhancement by allowed means. 3rd international football medicine conference, sun city, south africa, 2010. 19. hoppeler hh, kamber mf, melia ps. doping and prevention of doping. international co-operation. clin j sport med 1995;5:79-81. 20. verroken m, mottram dr. doping control in sport. in: mottram dr, ed. drugs and sport, 2nd ed. london: e&fn spon, 1996. 48 sajsm vol. 26 no. 2 2014 original research objectives. to compare the relationship between peak bone strain scores (pbsss) calculated from physical activity (pa) questionnaires and accelerometry measures of pa with trabecular and cortical bone properties in prepubertal children. methods. we compared pbsss calculated from the bone-specific component of pa questionnaires with accelerometry and bone mass measures in 38 prepubertal children (mean 9.9 (standard deviation 1.3) years). dual energy x-ray absorptiometry (dxa) and peripheral quantitative computed tomography (pqct) were used to assess bone content and structure, and to estimate bone strength at the radial and tibial diaphysis and radial metaphysis. results. the pbss was reliable and reproducible with significant (p<0.001) intraclass correlation coefficients. there were significant correlations between pbss and moderate (r=0.38; p=0.02), vigorous (r=0.36; p=0.03) and combined moderateto vigorous-intensity activity counts (r=0.38; p=0.02). pbss was significantly correlated to body size-adjusted bone mineral content at all sites scanned by dxa (r=0.33 0.48; p<0.05). positive correlations were observed between pbss and area, density and strength at the radius and tibia (r=0.40 0.64; p<0.05). only vigorous activity was correlated to cortical area at the radial diaphysis (r=0.37; p=0.03) and bone strength at the tibial diaphysis (r=0.32; p=0.05). activity as assessed by the pbss explained a greater amount of variance in bone variables as measured by dxa and pqct than accelerometer-measured pa. conclusion. accelerometer-measured moderate and vigorous habitual pa is associated with indices of cortical bone size and geometry in children, whereas light pa has no detectable association. furthermore, the bone-specific questionnaire appears to be more strongly associated with bone outcomes than accelerometer-derived measures of pa. s afr j sm 2014;26(2):48-54. doi:10.7196/sajsm.507 associations of objectively and subjectively measured physical activity with trabecular and cortical bone properties in prepubertal children r meiring, msc; j a mcveigh, phd exercise laboratory, school of physiology, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: r meiring (rebecca.meiring@wits.ac.za) preand early pubertal children who perform weightbearing physical activities (pas) that load major axial and appendicular bones have denser and stronger bones than less-active children.[1] two of the most common pa assessments used for research purposes are accelerometry and pa questionnaires (paqs). accelerometry is a reliable and acceptable method of assessing energy expenditure in children.[2] for the surrogate assessment of bone loading, no such standard exists and researchers rely on paqs as proxy assessments. the iowa bone development study has shown good associations between accelerometer-measured time spent in moderateto vigorous-intensity pa (mvpa) and changes in bone mineral content (bmc), bone mineral density and bone area as measured by dual energy x-ray absorptiometry (dxa) in children.[1] accelerometers have also been shown to be useful in detecting ground reaction force exerted by different types of activity, although there is inconsisten cy between types/brands of accelerometers.[2] one study has shown that accelerometer-measured vigorous-intensity activity, more so than moderate, is a significant predictor of bmc of the total body as well as at the femoral neck of 9-year-old children, while in children of similar age, nor aini et al.[3] indicated that there is better agreement between increased bmc and moderate-intensity exercise. the paq is a validated questionnaire[4] that can be used to survey sport, habitual and leisure-time pa. the paq has been used to ass ess pa in children and adolescents,[5,6] and mcveigh et al.[5] developed a mechanical-loading, bone-relevant paq algorithm (the peak bone strain score (pbss)) that incorporates pa duration, frequency and weight-bearing load. few studies have validated bone-specific algorithms from general paqs in children,[7,8] and although bonespecific questionnaires do exist, their ability to predict bone indices in children has not been assessed. in addition, the ability of the pbss algorithm to predict volumetric bone parameters of children has not been studied. although dxa remains useful for monitoring bone response to exercise, dxa measurements do not assess bone geometry, and small increments (due to loading pas) on the periosteal surface of the bone may be missed.[9] the use of peripheral quantitative computed tomography (pqct) provides structural and true density measures of paediatric bone[10] and thus allows delineation of the effects of exercise intensity on bone. farr et al.[11] examined the relationship between bone strength as measured by pqct and pa assessed using a pedometer and paqs, and found that a past-year paq was a better predictor of bone strength indices (bsis) than a pedometer. pedometers may be limited in their ability to reflect time spent in mvpa as they only measure steps per day mailto:rebecca.meiring@wits.ac.za sajsm vol. 26 no. 2 2014 49 and have a high amount of variability when used by people with different gait patterns.[2] only one group has assessed the relationship between accelerometr y measures and pqct bone outcomes, and found that in adolescents, vigorous – not light or moderate – pa was associated with bone geometric measures and indices of bone strength at the diaphysis of the tibia.[12,13] the relationship between pqct-measured bone outcomes and pa assessment (using accelerometry and questionnaires) in preand early pubertal children remains largely unknown. a valid, simple and effective weight-bearing activity assessment questionnaire would be of value in studies in poorer communities as more technical assessments are often not feasible. we therefore sought to compare the relationship between pbss calculated from the paq and accelerometry measures of pa with trabecular and cortical bone properties in prepubertal children. methods participants cross-sectional data were obtained from a convenience sample of 45 participants recruited from local schools in the greater johannesburg area. participants who responded to advertisements and distributed flyers were screened to determine their eligibility for the study. based on previously published correlation coefficients between paqs and accelerometry data, which range between 0.40 and 0.60,[7,14] we chose a value of 0.50 (moderate strength) and conducted a sample size calculation. it was estimated that a sample size of 38 children was needed at a power of 87% to ascertain a correlation coefficient of this size. screening included a self-assessment of pubertal status using the tanner fivestage classification criteria.[15] a general health questionnaire was administered to the primary caregiver of each child; children were excluded if they had been on corticosteroid medication for more than 7 consecutive days in the past year, if they had milk or lactose food allergies, if they were on a vitamin d or calcium supplement, or if they had been ill or admitted to hospital in the last 3 months prior to participation in the study. girls were excluded if they had attained menarche. all children who participated in the project had the study protocol verbally explained to them and, if they agreed to participate, signed an assent form. primary caregivers were required to consent to their child’s participation in the project. the project was approved by the human research ethics committee of the university of the witwatersrand (protocol number: m10635), which adheres to the principles of the declaration of helsinki. anthropometry participant height and weight were recorded to the nearest millimetre and 100 g using a stadiometer (holtain, uk) and a digital scale (dismed, south africa), respectively. body mass index percentile for age was calculated using software available from the world health organization (who, http://www. who.int/childgrowth/software/en). radial and tibial lengths (to the nearest millimetre) were measured using sliding callipers (hol tain, uk) for the determination of the position of the bone scans. radial length was defined as the distance from the tip of the olecranon process to the most distal end of the ulna styloid process. tibial length was defined as the distance from the distal end of the medial malleolus to the superior aspect of the medial tibial condyle. physical activity questionnaire (paq) children were required to complete the paq (with the assistance of their primary caregiver) on their participation in physical and leisure-time activities for the previous 2 years. information was gathered from four activity question domains, namely pa participation during school, extramural/afterschool pa, leisure-time activity and mode of transport to and from school. children were asked to provide details on the number of times per week they performed an activity, as well as the amount of time they spent on each activity at any one time, to determine the frequency of each pa. a regular activity was defined as that which was performed once a week for more than 4 months of the year (the usual length of a school semester in south africa). each regular activity was then assigned a bone strain score using a scoring system based on that of groothausen et al.[16] (table 1). a pbss was calculated for each participant. the pbss incorporated duration (defined as average minutes/session), frequency (sessions/week) and load (peak strain score). the sum of the scores for each activity made up the pbss for each child. the paqs for all children were filled out for the previous 2 years (april 2010 april 2012) to account for seasonal and annual variation in pas. the paq was re-administered 6 months later. a modified version of the questionnaire was also administered for the week in which the participants wore the actical (and again 6 months later) to ensure that the week was representative of a typical active week for the participants. accelerometry children wore an actical accelerometer (phillips, usa), which was secured using an elasticised waist belt to the hip of the right leg for 7 consecutive days. the actical was removed when participants showered, bathed or swam and this was recorded on the 7-day paq. the actical was collected after 7 days and the data were downloaded and analysed independently of the paq data. activity counts were collected in 15-second epochs and data were reduced by removing only full days of non-wear time as assessed either by observation of the data, where a full day of consistent zero activity counts was recorded, or as indicated by the participant if a day of wearing the actical was missed. the remaining data are referred to as the ‘wear period’. participant data were included if, out of the 7 days, there was a minimum of 4 days of wear time where 10 hours of consecutive total activity and activity counts were recorded per day. light, moderate and table 1. peak bone strain scoring system based on associated ground reaction forces* peak score estimation criteria examples 3 activities including jumping actions basketball, netball, gymnastics 2 activities including sprinting and turning actions badminton, baseball, tennis 1 weight-bearing activities dancing, jogging 0 all other activities bicycling, swimming *adapted from groothausen et al.[15] http://www 50 sajsm vol. 26 no. 2 2014 vigorous activity categories were defined according to activity count thresholds based on guidelines recommended for children between the ages of 7 and 18 years:[17] light activity = 300 1 499 counts per minute; moderate activity = 1 500 6 500 counts per minute; vigorous activity = >6 501 counts per minute. the actical output variables were total activity counts per minute and daily minutes spent in either moderate and/or vigorous activity. dual energy x-ray absorptiometry (dxa) bmc was measured by a trained technician using dxa (hologic qdr, discovery w, usa) at the following sites: forearm (ulna and radius), whole body, lumbar spine, total hip and femoral neck. the same technician performed and analysed all dxa scans. the coefficients of variation for bmc over the course of the study was 0.36%. peripheral quantitative computed tomography (pqct) measures of the forearm and tibia were conducted using pqct (stratec xct 2000, stratec medical, germany). a scout view was performed for each participant and a reference line placed at the midline of the epiphyseal plate of the radius and the tibia. scans of 2.3 mm thickness were done at 4% and 65% of the length of the radius from the reference line, and at 65% of the length of the tibia from the reference line for the measurement of bone area, density and strength. strength, periosteal circumference (pc), endosteal circumference (ec) and cortical thickness (ct) were also calculated. muscle cross-sectional area (mcsa) was obtained from the 65% site as this site is associated with the largest muscle belly. for the 4% radial measures, the bone threshold was set at 180 mg/cm3 and contour mode 1/peel mode 1 was used. for the cortical and bone geometry measures at the 65% radial and tibial sites, bone threshold was set at 711 mg/cm3 (contour mode 1/ peel mode 2). threshold for ssi at these sites for both the radius and tibia was set at 480 mg/cm3. for the measures of mcsa, threshold was set at 40 mg/cm3 (contour mode 3/peel mode 1). the same independent technician performed all pqct scans. a quality-control phantom spine was scanned each morning before 9 o-clock and before any participant scans were performed, with the coefficient of variation for total attenuation at 0.44% and trabecular attenuation at 0.37% during the study period (from april 2012 to october 2012). an acceptable and true representation of the 4% tibia (metaphysis) was not available for all participants (n=16 available) because the lower limbs of some participants were too short for an acceptable scan at that site. thus the 4% tibia was excluded from the final analysis. statistical analysis the pbsss calculated from the 2-year paq and the 7-day paq were compared using a wilcoxon signed rank test. intraclass correlation coefficients (one-way random effects model) were used to evaluate the reproducibility of the estimates of two administrations of the 2-year and 7-day pbsss. the initial 2-year pbss (indicative of bone loading history) was used for subsequent analyses. pbsss and actical activity (counts/min) were log transformed as data were not normally distributed. pearson’s correlations were then performed between pbss and moderate, vigorous and mvpa, and between logtransformed pbss, actical activities and adjusted bone variables. dxa measurements were adjusted for bone area, body mass and sex, while pqct values were adjusted for limb length, body mass and sex. multiple regression analyses were used to determine the independent contribution of pa measures (pbss and mvpa) on the variance of selected dxa (femoral neck, spine and hip) and pqct (cortical area (coa), density and strength of the 65% radius and tibia) derived variables after adjustment for the abovementioned covariates. mvpa, pbss and the covariates were entered into the models using a forced option. unless otherwise specified, data are presented as mean (sd). data were analysed using spss 21.0 (ibm spss, usa). significance was set at p≤0.05. results seven children were excluded from the analysis due to a lack of actical data that met the criteria for a ‘wear’ day. therefore 38 child ren’s data were included in the final analysis. participant characteristics are shown in table 2. relationship between pbss and actical-derived pa the 2-year and 7-day pbsss were comparable between administrations and demonstrated high intraclass correlations (table 3). there were significant positive correlations between pbss and moderate (r=0.38; p=0.02), vigorous (r=0.36; p=0.03) and combined mvpa (r=0.38; p=0.02). bivariate correlations between activity and bone pbss was significantly correlated to body size-adjusted bmc at all sites scanned by dxa (except the radius) (table 4). in addition, at the 65% radius, correlations were significant for total area (toa) (p<0.001), coa (p=0.001), cortical density (cod) (p=0.001) and strength-strain index (ssi) (p=0.002). pbss was also significantly correlated to pc (p=0.003) and ct (p=0.05) of the radius at the 65% site. at the 65% site of the tibia, toa (p=0.001), cod (p=0.03), ssi (p=0.001), pc (p=0.001) and ec (p=0.006) were all significantly and positively correlated to pbss. pbss was also significantly correlated to both arm (p<0.001) and leg (p=0.002) mcsa. total activity (counts/min) as measured by accelerometry was significantly correlated to body size-adjusted bmc at the spine (p=0.04), hip (p<0.001) and femoral neck (p<0.001). however, total activity was not correlated to any of the bone variables measured by pqct. similarly, moderate activity was significantly correlated to bmc at the femoral neck (p=0.04), whereas vigorous activity was correlated to bmc at the hip (p=0.03). when both moderate and vigorous activity were combined, significant correlations were seen for bmc at the femoral neck only (p=0.05). at the 4% radius, significant correlations between moderate activity and mvpa combined were seen for total density (p=0.01 and p=0.01, respectively). moderate activity was also correlated to bsi at the 4% radius (p=0.02). vigorous activity was correlated to coa (p=0.03) and forearm mcsa (p=0.01) at the 65% radius. there was no correlation between either moderate or vigorous activity and other pqct-measured radial bone variables. there was a trend for toa (p=0.07) and coa (p=0.08) of the tibia to be correlated to vigorous activity. significant correlations were observed between forearm mcsa and moderate-intensity activity. linear regression analysis a summary of the results from the multiple linear regression analysis is presented in table 5. although small, pa as assessed by the pbss sajsm vol. 26 no. 2 2014 51 explained significantly more variance in bmc of the femoral neck, spine and total hip compared to mvpa as measured by the actical accelerometer. in addition, at the cortical sites of the radius and tibia, variance in area, density and strength were explained more by the pbss than by mvpa. discussion whereas we observed moderate correlations between intensity of activity (assessed by the actical) and bone health indices of the radius and tibia, the associations between accelerometry measures and bone area and content were weaker compared with those obser ved between the pbss algorithm and size and content of bone. in the current study, mvpa was moderately associated with pbss. nor aini et al.[3] (in children of similar age to our study) showed lessstrong associations between their paq and actical-derived moderate activity, due in part to their participants overor underreporting vig orous activities.[3] we may have observed stronger correlations between objectively measured activity and pbss because we assess ed activity over 2 years to account for variations in annual changes in sport. similar to other studies that have found associations between paqs and bmc at the femoral neck, hip and spine,[1] in our study pbss was not only significantly associated with spine, hip and femoral neck bmc but also with ulna bmc. children who take part in upper-extremity sports have greater bone mass, strength and area at the proximal and distal radius.[18] on secondary analysis, we found that participation in tennis (in both boys and girls) and netball (in girls) – sports that use arm movement – was common in children who participated in this study (n=24 taking part in at least one of the abovementioned sports on a regular basis). in our study, pbss was also associated with forearm and leg muscle cross-sectional area, indicating the ability of the score to reflect the close relationship that exists between muscle and bone. our study also indicated the usefulness of the pbss algorithm in predicting bone size and geometry as measured by pqct. farr et al.[8] investigated associations between a paq and pqct bone measures and reported that associations between a pastyear pa recall and bsis were stronger than between pedometry and bone outcomes. similarly, in the present study, stronger associations between pbss and area of cortical bone, bsi and pc were observed, than between accelerometery and bone outcomes. the fact that the paq in the present study was bone-specific was the most probable table 2. descriptive characteristics of participants* characteristic whole group (n=38) age (years) 9.9 (1.3) tanner (i/ii) 22/16 sex (male/female) 12/26 race (white/black) 32/6 height (cm) 137.7 (9.9) body mass (kg) 32.9 (7.2) bmi percentile 52.5 (27.5) forearm mcsa (mm2) 1 758.7 (313.7) leg mcsa (mm2) 3 577.6 (673.9) physical activity moderate activity (min/day) 55.6 (23.5) vigorous activity (min/day) 2.1 (3.0) wear time (hours/day) 14.1 (0.9) days worn 6 (1) pbss from paq (2-year) 6.3 (3.1) dxa† ulna bmc (g) 2.5 (0.4) radius bmc (g) 3.6 (0.7) spine bmc (g) 23.2 (5.0) hip bmc (g) 16.7 (3.7) femoral neck bmc (g) 2.8 (0.5) whole body bmc (g) 781.6 (155.5) pqct† metaphysis-radius toa (mm2) 227.0 (49.6) tod (mg/cm3) 289.1 (14.6) trabd (mg/cm3) 211.1 (33.6) bsi (mg2/mm4) 1 878.9 (515.3) diaphysis-radius toa (mm2) 101.2 (14.6) coa (mm2) 44.6 (8.8) cod (mg/cm3) 998.9 (32.7) ssi (mm3) 149.2 (37.7) pc (mm) 34.9 (3.1) ct (mm) 1.5 (0.3) ec (mm) 25.6 (3.2) diaphysis-tibia toa (mm2) 436.6 (64.5) coa (mm2) 213.4 (33.2) cod (mg/cm3) 1 037.3 (17.8) ssi (mm3) 1 549.4 (393.1) pc (mm) 74.0 (5.3) table 2 (continued). descriptive characteristics of participants* characteristic whole group (n=38) ct (mm) 3.39 (0.4) ec (mm) 52.7 (4.3) bmi = body mass index; mcsa = muscle cross-sectional area; pbss = peak bone strain score; paq = physical activity questionnaire; dxa = dual energy x-ray absorptiometry; bmc = bone mineral content; pqct = peripheral quantitative computed tomography; toa = total area; tod = total density; trabd = density of trabecular bone at 4% site; bsi = bone strength index; coa = cortical area; cod = cortical density; ssi = strength-strain index; pc = periosteal circumference; ct = cortical thickness; ec = endosteal circumference. *data are mean (sd) except for tanner, sex and race, which show proportions within the group. † bmc measures by dxa are adjusted for sex, body mass and bone area, while pqct measures are adjusted for sex, body mass and limb length. continued... 52 sajsm vol. 26 no. 2 2014 table 3. intraclass correlation coefficients (r) comparing two administrations of the paq 1st administration 2nd administration icc (ci) p-value past 2-year pbss, median (iqr) 5.0 (4.0 8.0) 5.56 (3.0 8.8) 0.86 (0.76 0.91) <0.001 past 7-day pbss, median (iqr) 4.0 (2.0 5.0)  4.0 (4.0 6.0)  0.84 (0.16 0.97) <0.05 paq = physical activity questionnaire; icc = intraclass correlations; ci = confidence interval; pbss = peak bone strain score; iqr = interquartile range. table 4. correlation coefficients (r) between adjusted bone variables and pbss score from the paq and accelerometer-derived activity counts/minute   pbss total activity moderate vigorous moderate to vigorous bmc (g)* ulna 0.42† 0.10 0.07 0.15 0.03 radius 0.32 0.27 –0.03 0.08 –0.05 spine 0.47‡ 0.37† 0.17 0.30 0.15 whole body 0.44‡ –0.08 0.10 0.25 0.09 hip 0.50‡ 0.43† 0.26 0.36† 0.26 femoral neck 0.57§ 0.50‡ 0.34† 0.30 0.32† pqct* metaphysis-radius toa (mm2) 0.30 0.07 0.23 0.26 0.19 tod (mg/cm3) –0.03 0.09 0.41† 0.15 0.40† trabd (mg/cm3) –0.22 –0.08 0.24 0.18 0.24 bsi (mg2/mm4) 0.18 0.13 0.39† 0.33 0.33 diaphysis-radius toa (mm2) 0.56§ –0.18 0.17 0.20 0.16 coa (mm2) 0.52‡ –0.07 0.03 0.37† 0.06 cod (mg/cm3) 0.51† 0.11 0.06 0.28 0.06 ssi (mm3) 0.50‡ –0.16 –0.03 0.15 –0.03 pc (mm) 0.60‡ 0.003 0.34 0.22 0.35 ct (mm) 0.41† –0.13 0.10 0.29 0.10 ec (mm) 0.38 –0.15 0.27 0.06 0.27 forearm mcsa (mm2) 0.64§ 0.27 0.31 0.41† 0.31 diaphysis-tibia toa (mm2) 0.52‡ 0.09 0.25 0.30 0.24 coa (mm2) 0.31 0.10 0.15 0.30 0.14 cod (mg/cm3) 0.36† –0.20 0.01 0.16 0.03 ssi (mm3) 0.51‡ 0.06 0.21 0.32 0.19 pc (mm) 0.54‡ 0.04 0.23 0.28 0.21 ct (mm) 0.08 0.03 0.02 0.19 0.003 ec (mm) 0.62§ 0.02 0.25 0.22 0.24 leg mcsa (mm2) 0.52‡ 0.14 0.18 0.26 0.16 pbss = peak bone strain score; paq = physical activity questionnaire; bmc = bone mineral content; toa = total area; tod = total density; trabd = density of trabecular bone at 4% site; bsi = bone strength index; coa = cortical area; cod = cortical density; ssi = strength-strain index; pc = periosteal circumference; ct = cortical thickness; ec = endosteal circumference; mcsa = muscle cross-sectional area. *bmc measures by dxa are adjusted for sex, body mass and bone area while pqct measures are adjusted for sex, body mass and limb length. † p<0.05 ‡ p<0.01 § p<0.001 sajsm vol. 26 no. 2 2014 53 reason that strong correlations were seen between the pbss and bone outcomes measured by pqct and dxa. in our study, we did not find that vigorous-intensity activity was more closely related to bmc than moderate, as has been shown previously.[1,19] rather, we found that moderate and combined mvpa were significantly associated with bmc at the femoral neck, whereas vigorous activity was associated with bmc at the hip only. the positioning of the accelerometer on the hip as well as its limited ability to accurately detect movement in three-dimensional planes may have been a reason for associations in activity only being evident at the hip and femoral neck but not at any of the other sites assessed by dxa. at the metaphysis of the radius, a site that is susceptible to wrist fracture during growth, moderate and combined mvpa were associated with bone strength, while at the cortical tibia only vigorous activity was associated with bone strength. previous studies that have examined associations between bsis at the radius and tibia and activity-measured accelerometry[12,13] report similar findings to those of our study. pedometers are not as accurate a method of assessing activity as accelerometry[2] and the strength of the relationships reported in the farr et al.[11] study (using pedometers) was not as strong as seen in our study. farr et al. also showed that girls with the highest levels of duration and frequency of weight-bearing activity had greater strength at the tibia compared to girls with lower levels of weight-bearing activity without any changes in cod.[11] vigorous activity was associated with coa at the radius but no significant association was seen between vigorous activity and radial strength. a study in prepubertal tennis players, however, has shown that resistance to torsion and bending (i.e. greater ssi) is due to increases in coa as a result of periosteal apposition, and not necessarily bone density.[20] study limitations the two-dimensional nature of dxa measurements is consistently problematic in interpreting bone data in children. however, we controlled for this by limiting participation in this study to children who were classified as being prepubertal and using appro priate body size covariates in the statistical analysis. the actical has limited ability to accurately assess the intensity of specific types of activity, such as weight-bearing activities, cycling and swimming, and the positioning of the actical may also have contributed to the difference in associations seen between the pbss and the actical. the use of different cut points table 5. multiple linear regression on mvpa and pbss as predictors of bone outcomes measured by dxa and pqct goodness of fit correlations model adjusted r2 p-value outcome factors model parameter, unstandardised beta (se) p-value zero partial collinearity, vif dxa derived bone mineral content of the femoral neck, spine and hip 1 0.24 0.003 femoral neck pbss 1.1 (0.3) 0.002 0.53 0.50 1.6 mvpa 0.01 (0.40) 0.962 0.21 <0.001 1.3 2 0.19 0.009 spine pbss 10.7 (3.3) 0.003 0.48 0.48 1.6 mvpa –2.0 (3.6) 0.581 0.11 –0.09 1.3 3 0.19 0.009 hip pbss 7.9 (2.5) 0.003 0.49 0.47 1.6 mvpa –0.7 (2.7) 0.785 0.15 –0.05 1.3 pqct (65% radius bone variables) 4 0.28 0.002 toa pbss 35.9 (9.3) 0.001 0.56 0.56 1.6 mvpa –5.1 (10.1) 0.616 0.13 –0.09 1.5 5 0.27 0.002 coa pbss 22.3 (5.7) <0.001 0.52 0.56 1.6 mvpa –8.7 (6.2) 0.172 –0.002 –0.24 1.5 6 0.24 0.004 cod pbss 77.7 (21.5) 0.001 0.52 0.53 1.6 mvpa –22.4 (23.3) 0.343 0.05 –0.17 1.5 7 0.27 0.002 ssi pbss 93.7 (24.4) 0.001 0.50 0.56 1.6 mvpa –44.3 (26.4) 0.103 –0.05 –0.28 1.5 pqct (65% tibia bone variables) 8 0.23 0.005 toa pbss 147.8 (43.2) 0.002 0.52 0.51 1.3 mvpa –19.7 (45.7) 0.670 0.13 –0.07 1.5 9 0.05 0.150 coa pbss 48.7 (24.6) 0.055 0.31 0.32 1.3 mvpa –13.3 (25.9) 0.611 0.04 –0.08 1.5 10 0.10 0.070 cod pbss 31.0 (12.8) 0.021 0.36 0.38 1.3 mvpa –10.4 (13.5) 0.448 0.02 –0.13 1.5 11 0.23 0.005 ssi pbss 910.1 (263.4) 0.001 0.51 0.51 1.3 mvpa –170.9 (278.6) 0.544 0.11 –0.11 1.5 mvpa = moderateto-vigorous intensity activity; pbss = peak bone strain score; dxa = dual energy x-ray absorptiometry; pqct = peripheral quantitative computed tomography; vif = variance inflation factor; toa = total area; coa = cortical area; cod = cortical density; ssi = strength-strain index. 54 sajsm vol. 26 no. 2 2014 for mvpa may also have contributed to the discrepancy in results between studies, therefore this study may only apply to activity studies using the actical accelerometer. in addition, the fact that the actical and the pbss measure activity in different ways may be considered a limitation of the study. the pbss has a loading component built into the calculation (i.e. estimates of ground reaction force), whereas the actical accelerometer measures energy expenditure. therefore the bone outcomes may be more closely associated with the pbss than the actical for this reason only. however, we believe that our results still reflect the benefits of participation in weight-bearing pa rather than the biasing toward a more effective tool of assessment. the load values assigned to activities reported on in our paq are based on pbsss reported in the literature and we acknowledge that we did not measure ground reaction forces in our sample. in our study, vigorous activity was not quite significantly correlated to tibial total and coa (p=0.07 and p=0.08, respectively) but this may be due to the small sample size and the relatively low levels of participation in vigorous activity in this cohort of children. we recommend similar analyses to be conducted in a larger sample size in the future. conclusion we have shown that the bone-specific component of our paq (pbss algorithm) is useful in the assessment of the relationship between participation in weight-bearing sport and bone health in prepubertal children. while the pbss algorithm was a significant predictor of bone health measured by dxa and pqct, accelerometer-measured activity did not predict bone health to the same extent as the pbss. in conclusion, the pbss generated from the paq can be used to reliably and accurately collect data on participation in weight-bearing exercise. references 1. janz kf, burns tl, levy sm, et al. everyday activity predicts bone geometry in children: the iowa bone development study. med sci sports exerc 2004;36(7):11241131. [http://dx.doi.org/10.1249/01.mss.0000132275.65378.9d] 2. ryan j, gormley j. an evaluation of energy expenditure estimation by three activity monitors. eur j sport sci 2013;13(6):681-688. [http://dx.doi.org/10.1080/17461391. 2013.776639] 3. nor aini j, poh bk, chee wss. validity of a children’s physical activity questionnaire (cpaq) for the study of bone health. pediatr int 2013;55(2):223-228. [http://dx.doi. org/10.1111/ped.12035] 4. mcveigh ja, norris sa. criterion validity and test-retest reliability of a physical activity questionnaire in south african primary school-aged children. south african journal of sports medicine 2012;24(2):43-48. [http://dx.doi.org/10.7196/sajsm.178] 5. mcveigh ja, norris sa, cameron n, pettifor jm. associations between physical activity and bone mass in black and white south african children at age 9 yr. j appl physiol 2004;97(3):1006-1012. [http://dx.doi.org/10.1152/japplphysiol.00068.2004] 6. thandrayen k, norris sa, pettifor jm. fracture rates in urban south african children of different ethnic origins: the birth to twenty cohort. osteoporos int 2008;9(1):20:4752. [http://dx.doi.org/10.1007/s00198-008-0627-x] 7. economos cd, hennessy e, sacheck jm, shea mk, naumova en. development and testing of the bones physical activity survey for young children. bmc musculoskelet disord 2010;11:195. [http://dx.doi.org/10.1186/1471-2474-11-195] 8. farr j, blew r, lee v, lohman t, going s. associations of physical activity duration, frequency, and load with volumetric bmd, geometry, and bone strength in young girls. osteoporos int 2011;22(5):1419-1430. [http://dx.doi.org/10.1007/s00198-010-1361-8] 9. seeman e, delmas pd. bone quality – the material and structural basis of bone strength and fragility. n engl j med 2006;354(21):2250-2261. [http://dx.doi. org/10.1056/nejmra053077] 10. binkley tl, berry r, specker bl. methods for measurement of pediatric bone. rev endocr metab disord 2008;9(2):95-106. [http://dx.doi.org/10.1007/s11154-008-9073-5] 11. farr jn, lee vr, blew rm, lohman tg, going sb. quantifying bone-relevant activity and its relation to bone strength in girls. med sci sports exerc 2011;43(3):476-483. [http://dx.doi.org/10.1249/mss.0b013e3181eeb2f2] 12. sayers a, mattocks c, deere k, ness a, riddoch c, tobias jh. habitual levels of vigorous, but not moderate or light, physical activity is positively related to cortical bone mass in adolescents. j clin endocrinol metab 2011;96(5):e793-e802. [http:// dx.doi.org/10.1210/jc.2010-2550] 13. deere k, sayers a, rittweger j, tobias jh. a cross-sectional study of the relationship between cortical bone and high-impact activity in young adult males and females. j clin endocrinol metab 2012;97(10):3734-3743. [http://dx.doi.org/10.1210/jc.2012-1752] 14. de ridder cm, kemper hcg, bertens mjm, et al. concurrent validity of a weightbearing activity questionnaire in prepubertal and pubertal girls and boys. ann hum biol 2002;29(3):237-246. [http://dx.doi.org/10.1080/03014460110075701] 15. tanner jm. normal growth and techniques of growth assessment. clin endocrinol metab 1986;15:411–451. 16. groothausen j, siemer h, kemper hcg, twisk j, welten dc. influence of peak strain on lumbar bone mineral density: an analysis of 15-year physical activity in young males and females. pediatr exerc sci 1997;9(2):159-173. 17. puyau mr, adolph al, vohra fa, zakeri i, butte nf. prediction of activity energy expenditure using accelerometers in children. med sci sports exerc 2004;36(9):16251631. [http://dx.doi.org/10.1249/01.mss.0000139898.30804.60] 18. burt la, greene da, ducher g, naughton ga. skeletal adaptations associated with prepubertal gymnastics participation as determined by dxa and pqct: a systematic review and meta-analysis. j sci med sport 2013;16(3):231-239. [http:// dx.doi.org/10.1016/j.jsams.2012.07.006] 19. sardinha lb, baptista f, ekelund u. objectively measured physical activity and bone strength in 9-year-old boys and girls. pediatrics 2008;122(3):e728–e736. [http:// dx.doi.org/10.1542/peds.2007-2573] 20. bass sl, saxon l, daly rm, et al. the effect of mechanical loading on the size and shape of bone in pre-, peri-, and postpubertal girls: a study in tennis players. j bone miner res 2002;17(12):2274-2280. [http://dx.doi.org/10.1359/jbmr.2002.17.12.2274] http://dx.doi.org/10.1249/01.mss.0000132275.65378.9d] http://dx.doi.org/10.1080/17461391.2013.776639] http://dx.doi.org/10.1080/17461391.2013.776639] http://dx.doi.org/10.1111/ped.12035] http://dx.doi.org/10.1111/ped.12035] http://dx.doi.org/10.7196/sajsm.178] http://dx.doi.org/10.1152/japplphysiol.00068.2004] http://dx.doi.org/10.1007/s00198-008-0627-x] http://dx.doi.org/10.1186/1471-2474-11-195] http://dx.doi.org/10.1007/s00198-010-1361-8] http://dx.doi.org/10.1056/nejmra053077] http://dx.doi.org/10.1056/nejmra053077] http://dx.doi.org/10.1007/s11154-008-9073-5] http://dx.doi.org/10.1249/mss.0b013e3181eeb2f2] http://dx.doi.org/10.1210/jc.2010-2550] http://dx.doi.org/10.1210/jc.2010-2550] http://dx.doi.org/10.1210/jc.2012-1752] http://dx.doi.org/10.1080/03014460110075701] http://dx.doi.org/10.1249/01.mss.0000139898.30804.60] http://dx.doi.org/10.1016/j.jsams.2012.07.006] http://dx.doi.org/10.1016/j.jsams.2012.07.006] http://dx.doi.org/10.1542/peds.2007-2573] http://dx.doi.org/10.1542/peds.2007-2573] http://dx.doi.org/10.1359/jbmr.2002.17.12.2274] 86 sajsm vol 19 no. 3 2007 introduction an unaccustomed bout of eccentrically biased exercise results in trauma to muscle and/or connective tissue. it is now well established that if a similar bout is repeated within several days 22 to several months, 15 there is a significant reduction in direct and indirect markers of muscle damage. 13 this response is referred to as the repeated bout effect and is believed to represent a positive training adaptation. 13 several hypotheses have been proposed in an attempt to explain this phenomenon. mchugh 13 has classified these hypotheses as the neural, mechanical, and cellular adaptation. 13 one aspect of the cellular adaptation hypothesis that is gaining in acceptance is related to the initial acute inflammatory response after the first bout of eccentrics. 16 although acute inflammation promotes healing, an undesirable ‘side-effect’ of this process involves the release of catabolic substances that inadvertently degrade surrounding healthy tissue. pizza and colleagues 18,19 have suggested that the repeated bout effect may be related to original research article changes in neutrophil count, creatine kinase and muscle soreness after repeated bouts of downhill running abstract objective. a primary objective was to examine circulating neutrophil count after repeated bouts of downhill running. an additional aim was to determine creatine kinase (ck) levels during the initial 12 hours, after repeated dhrs. design. eleven healthy, untrained caucasian males performed 2 x 60 min bouts of dhr (-13.5%), spaced 14 days apart, at a speed equal to 75% vo2max on a level grade. blood was collected before, after, and every hour for 12 hours, and every 24 hours for 6 days. absolute neutrophil count, ck, and delayed-onset muscle soreness (doms) were assessed. results were analysed using repeated measures anova (p<0.05) with appropriate post hoc tests. results. there were no significant differences in neutrophil count (p=0.24) during the 12-h period following run 1 (mean±se, 6.45±0.29 10 -9 .l -1 ) versus run 2 (5.96±0.09 10 -9 .l -1 ), or during the 24-h periods for run 1 (3.48±0.09 10 -9 .l -1 ) or run 2 (3.47±0.09 10 -9 .l -1 ). during the initial 12-h correspondence: lucille l smith department of sport, rehabilitation and dental sciences tshwane university of technology south africa e-mail: smithll@tut.ac.za tel : 012-382-5921 cell: 082-561-8932 lucille l smith (phd)1 stuart j semple (d tech)1 andrew j mckune (d tech)1 nevel neveling (biokinetics/m tech)1 miguel caldeira (biokinetics/b tech)1 jean-marie swanepoel (b tech)1 lebogang tsomele (b tech)1 melissa naidoo (bsc hon)1 emmanuel sibanda (m tech)2 1 department of sport, rehabilitation and dental sciences, tshwane university of technology, pretoria 2 department of statistical services, tshwane university of technology, pretoria period, there was a significant interaction effect (p=0.0001) for ck with differences between bouts seen between 3 12 h; differences remained evident at 24 h and at 96 144 h. in all muscle groups, doms was significantly lower after run 2 compared with run 1. conclusion. the lack of significance in neutrophils, as well as the early onset of difference in ck between run 1 and run 2 were attributed to the type of eccentric protocol used. it was proposed that future studies be more cognisant of whether the eccentric mode is predominantly low-intensity long-duration or high-intensity short-duration. pg86-93.indd 86 10/3/07 3:27:23 pm sajsm vol 19 no. 3 2007 87 an attenuated inflammatory response after the second bout. this suggestion has been supported by the observation that there is a significantly reduced number of circulating neutrophils after the second bout of eccentrics, compared with the first. since neutrophils are typically the first white blood cells to enter damaged tissue and are instrumental in initiating an acute inflammatory response they reasoned that reduced circulating numbers of neutrophils after bout two, would result in reduced infiltration into damaged tissue and a reduction in subsequent inflammatory events. in contrast to the findings of reduced neutrophilia after bout 2 ,18,19 a previous study 21 found no significant differences in neutrophil count when a second bout of eccentrically biased exercise was performed a few weeks after the initial bout. however, a primary difference between the two studies was the exercise protocol. pizza et al. 18,19 used highintensity, low-volume resistance-like eccentric contractions of the elbow flexors, while the aforementioned study 21 used repeated bouts of downhill running, which incorporated lowintensity high-volume aerobic-like eccentric contractions. an alternate reason for the lack of consensus between these studies could have been that in the previous downhill running study, 21 the intensity, the steepness of the gradient and the duration of the running bouts were not sufficiently strenuous. therefore, a primary purpose of the present study was to reexamine circulating white cell counts, specifically neutrophils and also monocytes after two bouts of downhill running, using a higher intensity and longer duration. serum creatine kinase (ck) has frequently been used as an indirect marker of muscle damage. with regard to repeated bouts of eccentrics, ck has consistently been shown to be significantly lower after the second bout of eccentrics. 3,8,14,18,21 however, in previous downhill running studies 3,5,21 ck was only measured at 24-h intervals; whether differences in serum ck are evident at an earlier time point after downhill running has not been investigated. thus, an additional purpose of this study was to assess total circulating ck at 3-h intervals during the initial 12 h, as well as at 24-h intervals for 6 d, following both downhill runs. methods subject selection eleven healthy, active but untrained caucasian males were recruited for the study; ‘untrained’ was defined as not having engaged in regular sport or physical activity for at least 6 months. selection criteria for subjects included the following: age between 18 and 30 years; no history of leg injury or any other medical condition that would be exacerbated by two bouts of downhill running; no regular usage of any anti inflammatory medication. initial screening the individuals selected to participate were scheduled for screening in the exercise testing laboratory (etl). during the first visit they were required to read and sign an informed consent previously approved by the university ethics committee and in accord with guidelines established by the american college of sports medicine. height and body mass were assessed. body composition was assessed using a 7-site skinfold caliper (harpenden, british instruments, london). the sites were: chest, midaxillary, triceps, subscapular, abdomen, supra-iliac, thigh). the equation used was: body density = 1.112 0.00043499 (sum of 7 skinfolds) + 0.00000055 (sum of 7 skinfolds) 2 – 0.00028826 (age). 1 assessment of vo2max and determination of individual running speeds subjects were instructed to eat a light meal 3 hours prior to the vo2max testing. to determine vo2max, subjects were required to walk/run on a treadmill using the bruce protocol. 1 the test was performed on a quinton 90 treadmill (quinton instrument co. seattle, washington). continuous respiratory measurements were recorded by means of the medgraphics cardio2 combined vo2 /ecg exercise system (medical graphics corporation chicago, illinois). throughout the test, heart rate was recorded at the end of each minute using a polar™ heart rate monitor (accurex 2, polar electro, finland). ratings of perceived exertion (rpe) were recorded at the end of each stage (every 3 minutes), as well as when subjects reached volitional exhaustion; the 15-point category scale was used. 1 the test was accepted as vo2max if two of the following criteria were attained: rer > 1.1 and/or; rpe > than 19 on the 15-point rpe scale, and/or maximum heart rate (hr) within ± 20 beats of age predicted hrmax. after the test, vo2max (ml.kg -1 .min -1 ) values were converted into metabolic equivalents (mets). seventy-five per cent of the peak met capacity was then calculated. metabolic equations were used to determine the speed on a level grade that would elicit this met capacity. 1 this treadmill speed was the designated speed for each subject for both downhill runs. eccentrically biased downhill run during the 72 h prior to the downhill run, subjects were instructed to ingest a normal mixed diet, to be well hydrated, and to refrain from any strenuous exercise. each subject performed two identical bouts of downhill running spaced 14 days apart (run 1 and run 2). on both days subjects ran between 5:00 am and 11:00 am and repeated runs were at approximately the same time for each subject. subjects were instructed to fast overnight, but were encouraged to drink ad libitum, to ensure euhydration. at the start of both runs, subjects warmed up for 5 minutes by running on a level grade at the pre-determined speed. the treadmill was then lowered to –13.5% and subjects ran for 60 min. heart rate was recorded at the end of each minute (polar™ heart rate monitor, accurex 2, finland). blood sampling on arriving in the laboratory, before run 1 and run 2, subjects were required to sit quietly for 10 min. a qualified phlebotomist then inserted a venous catheter (22 gauge, 2.2 cm), pg86-93.indd 87 10/3/07 3:27:23 pm 88 sajsm vol 19 no. 3 2007 which was kept patent for the following 12 h, using a saline solution. blood was drawn at the following times: pre-exercise, immediately after (post), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 h after (14 samples x 15 ml per sample = 210 ml blood over approximately 14 h). in addition, subjects were required to return to the etl 24, 48, 72, 96, 120 and 144 h later, for additional blood draws (6 days x 15 ml = 90 ml). at these times, a standard venipuncture was performed using an antecubital vein. plasma (5 ml whole blood) was collected in edta tubes and used for assessment of total and differential white cell count and for assessment of ck. serum (10 ml whole blood) was collected in serum separator tubes, allowed to stand at room temperature for 30 min and then spun down for 10 min at 2 000 x g. aliquots were frozen at –70°c in 0.5ml eppendorf tubes. subjects remained in the etl for 12 h after run 1 and run 2. they were provided with food and fluid and encouraged to eat, and especially to drink, ad libitum. total and differential white cell count values were assessed before and immediately after exercise, and then every hour for 12 h, as well as 24 144 h. total and differential white cell count were determined using a cell-dyn 3000 (abott laboratories, mountain view, ca) and analysed by laser-based flow cytometry. all samples were analysed within 16 h of collection. assessment of ck ck was assessed at the following times: before, immediately after, 3, 6, 9, 12, 24, 48, 72, 96, 120 and 144 h after exercise. blood ck concentrations were determined using a refletron blood analyser, which uses a colorometric assay procedure (boehringer mannheim gmbh, germany). edta blood (32 µl) was pipetted onto a refletron ck strip (roche diagnostics, indianapolis, in). the strip was inserted into the refletron analyser for 30 sec. printed results were recorded. if values were > 1 500 iu/l the sample was diluted with equal parts distilled water; 32 µl of this mixture was then pipetted onto a strip and rerun immediately. values of diluted blood were then doubled. assessment of doms subjective soreness ratings were assessed before exercise and at the following times after exercise: 6, 12, 24, 48, 72, 96, 120, and 144 h. subjects were asked to gently palpate and move various muscle groups through a comfortable range of motion. they were then asked to rate each muscle group individually, by placing an ‘x’ along a visual analogue scale (vas) of 10 cm. the verbal anchors on this scale were ‘1 = normal’ and ‘10 = very, very sore’. 19 the distance in centimeters from the beginning of the scale to their mark was measured and this represented the muscle soreness score for that particular muscle group. statistical analysis all dependent variables were analysed using a repeated measures anova. separate analyses were performed for the initial 12-h periods and for the 24-h periods with all values being compared with pre-exercise levels. significance was set at p<0.05. where significant main effects or interaction effects were found, a post hoc least square means was used. all values reported are means ± se. results physical characteristics of subjects physical characteristics of 11 subjects were: age (years) = 19.7±0.4; height (m) = 1.79±0.3; mass (kg) = 78.5±3.0; body fat (%) = 14.6±3.2; vo2max (ml.kg -1 .min -1 ) = 47.8±3.6. the main effects in this study were bout (run 1 versus run 2) and time (initial 12-h period and then 24-h intervals for 6 d). any interaction effects represented differences between bouts (run 1 versus run 2) at a specific time(s). values reported are means ± se. white cell counts neutrophil count (tables i and ii) for the initial 12-h period there was no significant bout (p=0.24) or interaction (p=0.4) effect. there was a significant time effect (p=0.0001). neutrophils were significantly elevated over baseline (3.30±0.76, 10 -9 .l -1 ) at 2 h (7.74±0.76, 10 -9 .l -1 ), 3 h (7.39±0.76, 10 -9 .l -1 ) and 4 h (9.69±0.78, 10 -9 .l -1 ). for the 24-h comparisons there were no significant run (p=0.9), time (p=0.9), or interaction (p=0.6) effects. monocyte count for the initial 12-h period there was no bout (p=0.06) or interaction (p=0.89) effect. however, there was a significant time effect (p=0.0001). from 4 h after exercise through 12 h, monocytes were significantly elevated over pre-exercise baseline levels (0.51±0.03, 10 -9 .l -1 ), with peak values seen at 6 h (0.89±0.03 10 -9 .l -1 ). for the 24-h comparisons there were no significant bout (p=0.12) time (p=0.62) or interaction (p=0.93) effects. creatine kinase (fig. 1) for the initial 12-h period there was a significant interaction effect (p=0.0001). post hoc testing revealed that values for run 1 were significantly higher than for run 2 at the following times: 3 h (557±48 v. 289±48 iu.l -1 ), 6 h (936±51 v. 402±48 iu. l -1 ), 9 h (1242±48 v. 514±48 iu.l -1 ) and 12 h (1243±58 v. 535±48 iu.l -1 ). there was also a significant bout effect (p=0.0001), with values for run 1 v. run 2 being 727±21 iu.l -1 v. 347±20 iu.l -1 , respectively. for the 24-h comparisons there was a significant interaction (p=0.0001) effect. post hoc testing revealed significant differences between run 1 and run 2, respectively, at 24 h (827±49 v. 319±49 iu.l -1 ), 96 h (533±49 v. 132±49 iu.l-1), 120 h (499±49 v. 141±49 iu.l -1 ) and 144 h (404±49 pg86-93.indd 88 10/3/07 3:27:24 pm sajsm vol 19 no. 3 2007 89 v. 153±49 iu.l -1 ). there was also a significant bout effect (p=0.0001). values for run 1 (456±9 iu.l -1 ) were significantly higher than for run 2 (174±19 iu.l -1 ). it was interesting to note that ck peaked at 9 h and 12 h after run 1 and run 2. delayed-onset nuscle soreness (doms) doms was reported in several different muscle groups which include the following: upper back (fig. 2a): there was a significant bout effect (p=0.0004), with run 1 being significantly higher (2.4±0.1) than run 2 (1.8±0.1). peak soreness for upper back occurred at 24 h for both runs (4.5±0.4 v. 2.6±0.4). lower back (fig. 2b): there was a significant bout effect (p=0.0001), with run 1 (2.4±0.1) being significantly higher than run 2 (1.6±0.1). peak soreness occurred at 24 h for run 1 (3.5±0.3) and run 2 (1.8±0.3). m. gluteus max (fig. 2c): there was a significant bout effect (p=0.0001), with run 1 (2.7±0.1) being significantly higher than run 2 (1.8±0.1). peak soreness occurred at 24 h for run 1 (3.8±0.4) and run 2 (3.1±0.4). quadriceps (fig. 3a): there was a significant bout (p=0.0001) effect with values for run 1 (3.1±0.1) being table i. neutrophil and monocyte count before and after repeated bouts (run 1 and run 2) of downhill running neutrophil count (10 -9 .l -1 ) monocyte count (10 -9 .l -1 ) time (h) run 1 run 2 run 1 run 2 before 3.209±1.073 3.400±1.073 0.500±0.033 0.509±0.033 after 4.418±1.073 4.856±1.073 0.463±0.033 0.491±0.033 1 6.909±1.073 6.368±1.073 0.518±0.033 0.509±0.033 2 7.957±1.073 7.526±1.073 0.645±0.033 0.663±0.033 3 7.636±1.073 7.139±1.073 0.654±0.033 0.636±0.033 4 7.405±1.130 6.624±1.073 0.731±0.035 0.727±0.033 5 7.265±1.072 6.109±1.073 0.808±0.033 0.800±0.033 6 6.979±1.130 5.809±1.073 0.931±0.035 0.845±0.033 7 6.773±1.073 5.527±1.073 0.860±0.033 0.854±0.033 8 6.702±1.130 5.245±1.073 0.841±0.035 0.782±0.033 9 6.627±1.073 5.082±1.073 0.809±0.033 0.727±0.033 10 6.396±1.129 4.927±1.073 0.733±0.035 0.709±0.033 11 6.182±1.130 4.791±1.073 0.778±0.035 0.718±0.033 12 5.809±1.072 4.682±1.073 0.718±0.033 0.672±0.033 before after 3 6 9 12 24 48 72 96 120 144 time (h) 0 200 400 600 800 1000 1200 1400 c re at in e k in as e (i u /l ) run1 run2  fig. 1. changes in blood levels of creatine kinase across time (before exercise through 144 h), for run 1 (circle) and run 2 (triangle). the cross symbol represents significant differences between bouts at specific times. table ii. neutrophil and monocyte count before and after repeated bouts (run 1 and run 2) of downhill running neutrophil count (10 -9 .l -1 ) monocyte count (10 -9 .l -1 ) time (h) run 1 run 2 run1 run 2 before 3.209±0.224 3.400±0.224 0.500±0.027 0.509±0.272 24 3.818±0.224 3.282±0.224 0.500±0.027 0.445±0.027 48 3.418±0.224 3.456±0.237 0.463±0.027 0.435±0.029 72 3.309±0.224 3.636±0.237 0.473±0.027 0.465±0.029 96 3.436±0.224 3.354±0.224 0.482±0.027 0.454±0.027 120 3.658±0.237 3.518±0.224 0.464±0.029 0.464±0.027 144 3.497±0.224 3.639±0.224 0.484±0.027 0.453±0.027 pg86-93.indd 89 10/3/07 3:27:24 pm 90 sajsm vol 19 no. 3 2007 significantly higher than for run 2 (1.6±0.1). there was also an interaction effect (p =0.0079), with run 1 being significantly higher than run 2 at 24 (5.0 v. 2.5) 48 (4.8 v. 2.2) and 72 h (4.3 v. 2.1). peak soreness occurred at 24 h for both runs. hamstrings (fig. 3b): there was a significant bout effect (p=0.0001). with run 1 (2.4±0.1) being higher than run 2 (1.6±0.1). peak soreness occurred at 48 h for run 1 (3.8±0.4) and at 24 h for run 2 (2.3±0.3). m. tibialis anterior (fig. 3c): there was a significant bout effect (p=0.0001), with run 1 (2.3±0.1) being higher than run 2 (1.5±0.1). peak soreness in this muscle group occurred at 72 h for run 1 (2.9±0.3) and at 48 h for run 2 (2.0±0.3). m. triceps surae (fig. 3d): there was a significant bout effect (p=0.0001) with run 1 (3.3±0.2) significantly higher than run 2 (1.9±0.2). peak soreness occurred at 72 h for run 1 (4.4±0.5) and at 24 h and 48 h for run 2 (2.7±0.5) discussion a primary finding of this study was the confirmation of results from a previous study, 21 that there were no significant differences in neutrophil count when comparing an initial bout with a subsequent bout of downhill running. this is contrary to previous findings after repeated bouts of high-intensity eccentrics, 17,18 where significantly lower levels of circulating neutrophils were found after the second bout. regarding ck, significant differences between bouts were seen at 3, 6, 9 12 and 24 h after both bouts, as well at 96, 120 and 144 h after exercise. we believe that this is the first study to report this disparity in ck so soon after bouts of downhill running. concerning doms, after run 1, it was interesting to note that soreness peaked at different times in different muscle groups. furthermore, peak soreness did not always occur at the same time points in the same muscle groups after run 1 and run 2. neutrophil and monocyte count neutrophilia is an important aspect of acute inflammation and has been reported to occur after an initial bout of unaccustomed eccentrics. 16 a critical aspect of neutrophilia is that the increased circulating count precedes the activation and migration of neutrophils into damaged tissue. 17 in addition, the subsequent presence of neutrophils in damaged tissue is an initiating event in the acute inflammatory response. 16 pizza et al. 17,18 have proposed that the reduced neutrophilia as well as the reduced activation of these cells after a repeated bout of eccentrics could, in part, be responsible for the repeated bout effect. they suggested that dampening of an initiating event could reduce the up-regulation of subsequent associated events. if the above supposition is correct, a central question is why the disparity in results between various studies, which for the most part confirm a repeated bout effect? 17,18 a noticeable difference between previous studies conducted by pizza et al. 17,18 and smith et al., 21 as well as in the present study, is the mode of eccentrically biased exercise used to induce muscle trauma. pizza et al. 17,18 had subjects perform two bouts of forced lengthening contractions of the forearm flexors of the non-dominant arm, separated by 3, 18 or 4 weeks; 17 it is proposed that this be regarded as highintensity, low-repetitions resistance-like eccentrics. on the other hand, in the present study and in a previous study, 21 the mode of exercise involved downhill running; it is proposed that this be regarded as low intensity, high repetitions aerobic-like eccentrics. 11,12,21 although much emphasis has been placed on differences in training adaptations associated with high-force resistance-like exercise, 14 versus low-force, high-repetitions, such as occurs in aerobic-like exercise, surprisingly, these differences have been virtually ignored in terms of exercise-induced muscle damage. during high-force eccentrics it is possible that the primary damage is within the muscle fibre per se, 10,14 since there is most likely actin and myosin cross-bridging throughout before 6 12 24 48 72 96 120 144 0 1 2 3 4 5 u pp e r b ac k run1 run2 a before 6 12 24 48 72 96 120 144 0.5 1.5 2.5 3.5 4.5 lo w er b ac k run1 run2 b before 6 12 24 48 72 96 120 144 time (h) 0 1 2 3 4 5 m g lu te u s m a x run1 run2 c  fig. 2. this represents changes in delayed-onset muscle soreness across time for (a) upper back and (b) lower back and (c) gluteus maximus. in all muscle groups there was a significant bout effect (p<0.05, not shown on the graph), with values for run 2 being consistently lower than for run 1. (1 = ‘normal’ and 10 = ‘very, very sore’). pg86-93.indd 90 10/3/07 3:27:25 pm sajsm vol 19 no. 3 2007 91 the range of motion during the lengthening contraction. however, during low-intensity high-repetition aerobiclike eccentrics, such as downhill running, 6 it is proposed that most of the external load is applied at the end of the movement, producing a braking/shock absorbing function during the foot strike, with low resistance and minimal actin and myosin cross-bridging as the muscles (e.g. quadriceps) move through the swing-lengthening phase of the running motion. if the primary force is only applied at the end of the action, it is possible that the primary stress is on collagen and tendon structures outside the muscle fibre; 10 this would be supported by findings of malm and colleagues, 11,12 who 27 before 6 12 24 48 72 96 120 144 0 1 2 3 4 5 run1 run2 a. gluteus m. before 6 12 24 48 72 96 120 144 0 1 2 3 4 5 run1 run2 b. hamstrings before 6 12 24 48 72 96 120 144 time (h) 0.5 1.0 1.5 2.0 2.5 3.0 3.5 run1 run2 c. m. tibialis before 6 12 24 48 72 96 120 144 time (h) 0 1 2 3 4 5 run1 run2 d. gastrocnemius fig. 3. these represent changes in delayed-onset muscle soreness across time for (a) quadriceps (cross symbol represents significant differences between run 1 and run 2 at each time), (b) hamstrings, (c) tibialis, (d) gastrocnemius. in all four areas, there was a significant bout effect (p<0.05, not shown on the graph) with values for run 2 being consistently lower than for run 1. (1 = ‘normal’ and 10 = ‘very, very sore’). pg86-93.indd 91 10/3/07 3:27:26 pm 92 sajsm vol 19 no. 3 2007 suggest that after downhill running, inflammatory factors are present in muscle epimysium and that the focal injury does not exist in muscle. it is proposed that during high-force resistance-like eccentrics the primary damage is to the muscle fibre, while during low-force aerobic-like eccentrics the primary damage is to structures outside the muscle fibre, such as collagen and tendons. 10 so differences in mode of exercise could induce differences in the target of injury. 5 whether this could induce differences in aspects of inflammation, such as differences in neutrophilia, is currently unknown. an alternate explanation for the lack of reduced neutrophil count in the present study, after run 2, could be that the body responds differently to a focal injury (biceps trauma) versus a more diffuse injury (stress to several major muscle groups such as quadriceps and gluteal muscle). undoubtedly the internal neuro-endocrine milieu is vastly different during these different forms of exercise/injury, and the role this may play in neutrophilia is currently not clear. although the focus has been on neutrophilia, monocytes/ macrophages form the second line of defense in acute inflammation. many monocytes/macrophages are resident in tissue (ed2 + ), while many migrate from the circulation (ed1 + ). in the present study there were no differences in monocyte count between the two runs. however, there was a significant time effect with blood monocytes being elevated over baseline levels between 4 and 12 h after both bouts of exercise; these changes were remarkably similar to what has previously been reported. 21 the principle that increased numbers of circulating cells precede migration to injured tissue would be in keeping with the notion that there is a similar infiltration of monocytes after both bouts of eccentrics. 9 creatine kinase although ck does not correlate with histological evidence of skeletal muscle damage 23 it is still consistently used as an indirect marker of muscle damage. 6,24 several notable observations were seen in the present study, in response to the downhill running. an interesting finding was related to significant differences between run 1 and run 2 starting at 3 h after the downhill running. previous studies, using downhill running, have generally taken blood samples starting at 24 h after the exercise bout. 2,3,12 we believe this is the first study to demonstrate that significant differences occur as early as 3 h after the downhill run. in the present study ck levels peaked between 9 and 12 h after both bouts. this early difference in ck seen after downhill running contrasts with differences reported after high-intensity resistance-like exercise (maximal exercise of elbow flexors). 6 after repeated bouts of elbow flexors, significant differences between ck levels after bout 1 and 2 are generally seen at a later time period 6 such as at 12 and 24 h 18 or at 3 and 4 d. 8 it is suggested that the significant differences in ck, in the present study, seen initially at 3 h after run 1 and run 2, as well as the time for peak values (9 12 h after run 1), were due to the mode of exercise. downhill running undoubtedly increases metabolic rate, as is evidenced by increased heart rates and oxygen consumption, 6 both during and after the exercise, compared with exercise that involves high intensity/ low repetitions and that induces more focal injury. the increased metabolic rate could have resulted in a more rapid efflux of creatine kinase from the damaged tissue into the circulation. 16 in the present study, the overall finding of significantly lower ck values after run 2 concurs with previous studies on the repeated bout effect. however, when comparing peak ck values between the different types of eccentric protocols, values are consistently lower for the downhill running protocols. 6 the peak mean ck seen in the present study was approximately 1 200 iu.l -1 compared with a mean peak ck of approximately 3 500 iu.l -1 reported by pizza et al. 18 the idea of lower ck levels being associated with eccentrically biased downhill running 6 would support the idea that there is less damage to the muscle fibers per se (as was suggested above) and possibly more damage focused on the extramuscle collagen and tendon structures. 4 an additional observation is related to changes in ck over the entire period (before exercise through 144 h after). as stated earlier, there was an initial peak between 9 and 12 h and then a secondary reduced, but significant peak at 96 and 120 h. this biphasic pattern is similar to that reported by schwane and armstrong, 20 in which rodents ran downhill on a treadmill, and is also similar to what was previously reported after downhill running in human subjects. 21 although speculative, it is suggested here that the initial peak reflects the primary mechanical injury, while the secondary peak reflects the secondary metabolic/biochemical injury. 7,14 delayed-onset muscle soreness doms was assessed in 7 different muscle groups. the highest levels of doms were reported in the quadriceps and the upper back. such high levels were unexpected in the upper back. however, it appears that this area involves a balancing/ braking action during downhill running. most soreness peaked at 24 h and then began to dissipate. however, doms remained elevated in the tibialis anterior and gastrocnemius through 72 h. in conclusion, a somewhat puzzling aspect of the comparisons between this study involving low-intensity, highrepetition aerobic-like eccentrics versus studies involving high intensity, low repetition resistance-like eccentrics, is that certain aspects of the repeated bout effect are similar (ck was significantly reduced, although less pronounced elevations were seen in this study; doms was also significantly reduced after run 2), while other aspects of this response differ (different responses in circulating numbers of neutrophils after run 2). it is suggested that future studies be more cognisant of the mode of eccentrics used when attempting to interpret the responses to tissue damage. pg86-93.indd 92 10/3/07 3:27:26 pm sajsm vol 19 no. 3 2007 93 references 1. american college of sports medicine. guidelines for exercise testing and prescription. 6th ed. baltimore, md: lippincott williams and wilkins, 2000. 2. armstrong rb, garshnek v, schwane ja. muscle inflammation: response to eccentric exercise. med sci sports exerc 1980; 12: s94-5. 3. byrnes wc, clarkson pm, white js, hseih ss, frykman pn, maughan rj. delayed onset muscle soreness following repeated bouts of downhill running. j appl physiol 1985; 59: 710-15. 4. cleak mj, eston rg. muscle soreness, swelling, stiffness and strength loss after intense eccentric exercise. br j sport med 1992; 26: 267-72. 5. eston rg, lemmey ab, mchugh p, byrnes c, walsh se. effect of stride length on symptoms of exercise-induced muscle damage during a repeated bout of downhill running. scand j med sci sports 2000; 10: 199-204. 6. eston rg, mickleborough j, baltzopoulos v. eccentric activation and muscle damage: biomechanical and physiological considerations during downhill running. br j sport med 1995; 29: 89-94. 7. faulkner ja, brooks sv, opiteck ja. injury to skeletal muscle fibers during contractions: conditions of occurrence and prevention. phys ther 1993; 73: 911-21. 8. hirose l, nosaka k, newton m, et al. changes in inflammatory mediartors following eccentric exercise of the elbow flexors. immunol rev 2004; 10: 75-90. 9. lapointe bm, fremont p, cote ch. adaptations to lenghtening contractions is independent of voluntary muscle recruitment but relies on inflammation. am j physiol regul integer comp physiol 2002; 282: r323-29. 10. lindstedt sl, lastayo pc, reich te. when active muscles lengthen: properties and consequences of eccentric contractions. new physiol sci 2001; 16 256-61. 11. malm c, nyberg p, engstrom m, et al. immunological changes in human skeletal muscle and blood after eccentric exercise and multiple biopsies. j physiol 2000; 529: 243-62. 12. malm c, sjodin b, sjoberg b, et al. leukocytes, cytokines, growth factors and hormones in human skeletal muscle and blood after uphill or downhill running. j physiol 2004; 556: 983-1000. 13. mchugh m. recent advances in the understanding of the repeated bout effect: a brief review. scand j med sci sports 2003; 13: 1-10. 14. nosaka k, newton m. differences in the magnitude of muscle damage between maximal and submaximal eccentric loading. j strength cond res 2002; 16: 202-8. 15. nosaka k, sakamoto k, newton m, sacco p. how long does the protective effect on eccentric exercise-induced muscle damage last? med sci sports exerc 2001; 33: 1490-5. 16. peake jm, nosaka k, suzuki k. characterization of inflammatory responses to eccentric exercise in humans. exerc immunol rev 2005; 11: 64-85. 17. pizza fx, baylies h, mitchell jb. adaptations to eccentric exercise: neutrophils and e-selectin during early recovery. can j appl physiol 2001; 26: 245-53. 18. pizza fx, davis bh, henrickson sd, et al. adaptation to eccentric exercise: effect on cd64 and cd11b/cd18 expression. j appl physiol 1996; 80: 47-55. 19. pizza fx, koh tj, mcgregor sj, brooks sv. muscle inflammatory cells after passive stretches, isometric contractions, and lengthening contractions. j appl physiol 2001; 92: 1873-78. 20. schwane ja, armstrong rb. effect of training on skeletal muscle injury from downhill running in rats. j appl physiol 1983; 55: 969-75. 21. smith ll, bond ja, holbert d, et al. differential white cell count after two bouts of downhill running. int j sports med 1998; 19: 432-37. 22. smith ll, fulmer mg, holbert d, et al. the impact of a repeated bout of eccentric exercise on muscular strength, muscle soreness, and creatine kinase. br j sports med 1994; 28: 267-71. 23. van der meulen jh, kuipers h, drukker j. relationship between exerciseinduced muscle damage and enzyme release in rats. j appl physiol 1991; 71: 999-1004. 24. warren gl, lowe da, armstrong rb. measurement tools used in the study of eccentric contraction-induced injury. sports med 1999; 27: 43-59. pg86-93.indd 93 10/3/07 3:27:26 pm introduction in the past cricket in most commonwealth countries was played solely during the summer months, but its popularity has increased so much that it has lost its ‘season’ and is now being played throughout the year. because of the longer season, cricket players are exposed to more demanding schedules, with more time spent training and practising. 7 this increase in workload may be a contributing factor to the increased incidence of injuries noted. researchers agree that the physical demands of the fast-bowling action can have a damaging effect on the bowlers concerned. studies done in south africa have shown bowling to account for 41% of injuries incurred. 7,8 in a more recent study by the australian cricket board it was reported that fast bowlers at first-class level significantly increased their risk of injury when their bowling workload exceeded more than 20 30 overs a week. 5 on average 1 in 6 elite australian fast bowlers was unable to play owing to injury at any given time. 1 an injury database has been established by the united cricket board of south africa to help to reduce the incidence of injury by identifying and predicting future injury, thereby utilising the information as guidelines for injury prevention. 7 this database is applicable to players at a provincial and national level. the statistics on schoolboy injuries indicate that more schoolboys are acquiring an ‘adult-like’ injury profile, favouring injuries to the back and trunk (33%), with the highest incidence of these injuries (47%) occurring among the young fast bowlers. 7 various factors, including the type of bowling action, have been associated with a risk of injury, with a ‘mixed’ bowling action associated with the highest number of lumbar spine injuries. these injuries, specifically stress fractures, can be caused by too much bowling or by a bowling technique fault that causes the spine to counter-rotate unnaturally, resulting in a stress fracture of the bone. 6 fast bowlers are especially prone to injury as they perform their bowling technique at a very high intensity. to ensure the next generation of elite fast bowlers remain injury free for as long as possible it is important to monitor schoolboy injuries with a view of identifying risk factors that could lead to appropriate intervention strategies and ultimately to prolonged cricket careers and a reduced incidence of injury. the aim of this study was to compile an injury profile of fast bowlers aged 11 18 years, and to identify the associated risk factors for injury during a normal academy cricket season. original research article cricket: nature and incidence of fast-bowling injuries at an elite, junior level and associated risk factors abstract objective. to compile an injury profile of 46 fast bowlers aged 11 18 years, and to identify the associated risk factors for injury during one academy cricket season. methods. the fast bowlers selected were tested and observed for one academy cricket season (march november). subjects were grouped into injury classifications (uninjured=s1; injured but able to play=s2; injured and unable to play=s3). anthropometrical and postural data for the subjects were collected preseason (t1). physical fitness screenings were conducted and the relationship between fitness and occurrence of injuries was assessed. additional factors such as bowling techniques and bowling workload were assessed. a regression analysis was conducted to analyse the relationship between bowling workload and weeks incapacitated. results. fifteen per cent of the subjects remained injury free for the duration of the season. the incidence of serious injury (s3) showed a statistical and moderate, practical significant increase (v=0.23, df≥2) throughout the data collection period (4% at t1 30% at t3 (post-season)). the most common injuries were to the knee (41%) and lower back (37%), occurring from mid-season (t2) to t3. the nature of the injuries was predominantly strains (39%) and ‘other’ (39%), with the highest reported incidence during the period t1 t3. sprains followed, with an overall incidence of 14%. subjects were incapacitated approximately 1 out of every 7 weeks of play. the s1 and s2 bowlers performed consistently better than the s3 bowlers in all the fitness variables tested. bowling workload presented a statistically significant (p<0.0005) increased risk of injury. a strong, significant positive relationship (r ² =0.62, p<0.0005) was found between the number of weeks incapacitated and bowling workload. correspondence: miss r davies po box 1273 oxenford, qld australia 4210 e-mail: roxy_davies@yahoo.com roxanne davies (b hms, ba (hms) hons (biokinetics), ma (hms)) rosa du randt (bsc (physed), mphysed, phd) danie venter (msc) richard stretch (dphil) nelson mandela metropolitan university, port elizabeth conclusion. the results indicated that inadequate fitness, high bowling workload and bowling technique all have a multifactorial role in predisposing a bowler to increased risk of injury. these variables did not act alone, but have all contributed to recurring injuries. sajsm vol 20 no. 4 2008 115 method forty-six junior fast bowlers aged 11 18 years underwent an initial screening in which anthropometrical and postural data were collected. a baseline overall fitness score, based on summated t-scores for each of the physical fitness components (flexibility, muscle strength and endurance, agility and aerobic capacity), was established before the start of the cricket academy training year (t1) (it is beyond the scope of this article to provide details of the fitness scores – these can be obtained from the author). the group was tested and observed throughout the data collection period (march november). at this stage each bowler received a bowling logbook in which he recorded and monitored bowling workload for the season. further information regarding fitness was collected on two other occasions, during t2 and t3. information obtained assisted in acquiring a fitness profile of the fast-bowling subjects during the study period. in addition to the fitness testing and screening the bowlers were required to complete two questionnaires implemented in this study. questionnaire 1 was completed by all participants while questionnaire 2 was completed only by those who had reported having sustained a particular injury. the questionnaires were handed out at the initial t1 contact session and returned at the t2 contact session. the nature of the questions asked allowed for the collection of data regarding the type of bowling technique used by each bowler, the number of injuries incurred, the specific body parts injured, the type of injury and the possible risk factors for injury. these questionnaires were based on those previously used in other cricket fast-bowling studies and modified for the purpose of this study. the statistica 7.1 statistics programme was used to analyse the raw data. changes in injury status throughout the season were analysed using a pearson chi-square test and a two-way cross tabulation. the significant difference in physical fitness performances was determined utilising an analysis of variance (anova) and the scheffé post-hoc procedure to determine which groups were significantly different. where statistical significant differences were detected either cohen’s d test or cramer’s v test was used to determine the practical significance of such comparisons. a multiple regression test was used to investigate the relationship between injury and bowling workload as a risk factor for injury. statistical significance is indicated by p-values <0.05 (p<0.05), while practical significance is indicated by either cohen’s d values of 0.2 or better (d>0.2) for tests based on sample means, or cramer’s v for tests based on sample frequencies. the significant value depends on the applicable degrees of freedom (indicated by df >0.2 in the text), but at least a minimum value of 0.10. all fitness scores as well as bowling workload figures were converted to standard t-scores and these in turn were summated to derive overall fitness and workload t-scores. it is important to note that tt indicates the overall average score for the entire season. changes in performances, bowling workload and injury status were analysed using various anova techniques, and analysis of covariance (ancova). a regression analysis was conducted to analyse the relationship between bowling workload and weeks. the relationship between injury and risk factors (bowling workload, bowling technique, fitness, past injury and recurrent injury) was analysed using ancova. ancova was also utilised to accommodate continuous variables in the analysis. these factors were relative to the number of weeks each bowler was incapacitated during the course of the study. during the data collection period the groups were re-classified into the following player status classifications: status 1 (s1) (uninjured). subjects who remained injury free for the entire data collection period, with injury being defined as any condition preventing or limiting player participation in a match or practice for an extended period of time (2 or more weeks). status 2 (s2) (not severely injured). subjects injured at the beginning of the data collection period, but who were able to continue with normal cricket activities during the data collection period. status 3 (s3) (severely injured). subjects who were unable to return to normal cricket activities during the data collection period owing to a debilitating injury sustained during the data collection period. results the average mean age of the participants in the study was 14.6 ± 2.0 years, with the oldest being 18 years of age. their average mean height was 170.0 ± 17.7 cm and weight 64.2 ± 16.8 kg. the overall physical fitness score, calculated as summated t-scores for the components of physical fitness, showed significant changes (p<0.05) between t1 (48.13) and t2 (51.34) and t1 and t3 (51.37). hyperextension of the knees was found to have the highest incidence (43%). lordosis and winged scapula were found among 39% of the subjects, closely followed by flat feet and pronating feet, with an incidence of 37% each (table i). the s1 and s2 bowlers generally performed better than the s3 bowlers, especially when considering the overall fitness scores for all the relevant variables. none of these differences however was significant (p>0.05), except in the case of hamstring flexibility (straight-leg raise test) during t1 and t2 as well as overall at tt (p<0.05, d>0.2) (table ii). during the course of the season 42% of the 46 subjects utilised at least one of the mixed bowling techniques. this was assessed using the bowler’s questionnaire and coach classifications according to video-analysis results. video data were collected by filming the bowlers in action from the front and side views. with the exception of 2 bowlers during t2, who utilised a combination of side-on and sideon mixed techniques (the lower body is at a side-on position and the table i. postural deviations of the total sample (n=46) physical characteristics n % hyperextended knees 20 43 lordosis 18 39 winged scapula 18 39 flat feet 17 37 pronating feet 17 37 kyphosis 12 26 supernating feet 9 20 knocked knees 8 17 scoliosis 2 4 bow legs 1 2 table ii. straight leg-raise score differences between the s1/s2 and s3 bowlers rather present the data at (mean ± sd) test: straight leg raise (degrees) t s1 & s2 s3 significance m sd m sd p d t1 83.17 8.36 74.53 8.90 0.003 1.01 t2 85.77 6.66 78.36 12.85 0.015 0.82 t3 84.03 8.23 86.33 9.05 0.542 na tt 84.32 6.39 77.64 9.12 0.006 0.90 116 sajsm vol 20 no. 4 2008 shoulders are in a front-on position), all subjects continued to utilise their original techniques from t1 to t3. anova indicated statistically significant changes in bowling workload over the study period (p<0.05). a post-hoc analysis revealed statistically significant changes between all test periods (p<0.05). cohen’s d tests confirmed that the practical significance of these changes can be described as small (0.2<d<0.5) for t2 and t3, and large (d>0.8) for t1 and t2 as well as for t1 and t3. at t1 28% of the participants reported being injury free for the past two cricket seasons, with 72% reporting an injury at one or more stage during the preceding two seasons and reporting at least 58 separate injuries. the s3 group increased significantly from 4% at t1 to 30% at t3. the overall results showed that only 15% of the players remained injury free during the course of the season, with 35% at some stage injured to such an extent that they were unable to play (table iii). the most common injuries were to the knee (41%) and lower back (37%), followed by ‘other’ (16%) and shoulder injuries (16%). the ‘other’ injury group included injuries to areas such as the groin, face, heel, toes, stomach and wrist. knee, shoulder and upper back injuries increased from t2 and t3, while lower back injury incidences remained the same throughout the season. ankle and finger injuries occurred predominantly at t1, reducing as the season progressed (fig. 1). strains and ‘other’ accounted for 39% of the injuries incurred (tt) and had the highest reported incidence during t1 t3. the category ‘other’ represented injuries such as abrasions, herniations, subluxations, unexplained pain syndromes and concussions. sprains accounted for 14% of the injuries. less frequently reported injuries were tears, fractures, bruises, breaks and dislocations. however, of the 15 lower-back injuries reported (fig. 1), 3 (20%) were stress fractures that occurred between t1 and t2. the categories of injuries that occurred more prevalently during t1 than t2 were sprains, tears and bruises, while those more prevalent during t2 than t1 or t3 were strains, fractures and ‘others’ (fig. 2). fifty-nine per cent of the participants reported having been injured in the two cricket seasons preceding testing at t1. over the three testing sessions many of these injuries were reported as recurring at t1 (41%) and t2 (41%) and increasing in incidence to 48% at t3. overall recurrent injuries accounted for 43% of reported injuries. bowling (41%) accounted for more injuries than those caused by other sports (28%) at tt. bowlers were incapacitated approximately 1 week out of every 7 weeks of play. the ‘not severely injured’ bowlers generally performed better than those who were ‘severely injured’, especially when considering the overall fitness scores for all the relevant variables. however, only hamstring flexibility (straight leg-raise test) during t1, t2 and overall at tt showed significant differences (p<0.05, d>0.2). the ‘severely injured’ bowlers (s3) showed higher bowling workloads than the ‘not severely injured’ bowlers (s2). of the risk factors analysed only bowling presented a statistically significant (p<0.05) increased risk of injury. a strong significant relationship (r ² =0.62, p<0.0005) was found between weeks incapacitated and bowling workload, supporting the finding that increased bowling workloads show a linear relationship with the increase in number of weeks incapacitated from normal play. where the regression formula, i.e. weeks incapacitated =-3.7842 + 0.0527 (balls bowled per week), is used for prediction purposes, it should be restricted to instances where a young fast bowler bowls between 60 and 300 balls per the approximate range of bowling workload used to derive the regression formula. discussion it is assumed that the timeous conditioning and monitoring of physical fitness throughout the season will assist in adequately preparing fast bowlers and thus assist in reducing injury. with regard to bowling fitness, each player should be able to identify his own weakness/es with regard to physical performance and to counteract these weaknesses. this could promote the assertiveness of each bowler to take care of his individual fitness needs with a view to reducing the risk of injury. the overall physical fitness of each subject involved in the current study improved marginally as the season progressed. physical fitness at t1 is more important than t2 fitness, as it has a significant relationship (p<0.05) to risk of injury throughout the rest of the year. this is supported by the findings that poor seasonal fitness table iii. incidence of injury from t1 to t3 injury status t1 (%) t2 (%) t3 (%) tt (%) s1 28 30 24 15 s2 67 61 46 50 s3 4 9 30 35 total 100 100 100 100 s1 – uninjured; s2 – injured but able to play; s3 – injured but unable to play. 0 5 10 15 20 25 30 35 40 45 50 knee lower back other shoulder ankle upper back fingers hip elbow % t1 t2 t3 tt fig. 1. seasonal injury incidence per anatomical area. fig. 1. seasonal injury incidence per anatomical area.fig. 2. the nature of injuries to fast bowlers. 0 5 10 15 20 25 30 35 40 45 50 strain other sprain tear fracture bruise break dislocation t1 t2 t3 tt fig. 2. the nature of injuries to fast bowlers. sajsm vol 20 no. 2 2008 117 conditioning may increase the risk of injury among fast bowlers. 3,7 fitness at t1 and t2 should be adequate to allow the bowlers to withstand the demands of the fast-bowling action. a high incidence of injury, however, was noted in the current study throughout the season, suggesting that the unconditioned bowler is at a greater risk of fatigue-related injury compared with his fitter, better-prepared counterparts. unfortunately, research did not yield any national or international data on the fitness requirements and specific profiles of fast bowlers for any age and/or level of play. the latter complicates matters with regard to identifying relevant weaknesses timeously and designing improvement programmes. an incorrect bowling technique can increase a bowler’s risk of serious injury, particularly to the lower back. 7 regular technique analysis is therefore essential to ensure that the bowler is bowling correctly at all times. bowling technique only does not seem to predispose a fast bowler to injury. a repeatedly faulty technique is more likely to play a role in injury incidence when coupled with an increased workload and poor physical preparation. in the current study it was found that there was a significant increase in bowling workloads between t1 and t2 (d>0.8). it was also observed that the most serious injuries occurred in bowlers with the highest bowling workloads. these bowlers compounded matters by continuing to bowl while injured, thus causing further injury. these findings are similar to those of dennis et al. 2 both studies identified excessive bowling workloads as a possible risk factor for injury. dennis et al. also found a significant relationship between low, infrequent bowling workloads and injury, concluding that workloads that are too high or too low have an equal risk of injury in a fast bowler. a possible ‘required workload’ exists that prevents injury by adequately conditioning the fast bowler to withstand the pressures of continued sessions of fast bowling. furthermore, a strong relationship was found between workload and weeks incapacitated (r ² =0.62, p<0.0005), indicating that excessive bowling workloads influenced the severity of injury to such a degree that there was a linear relationship between bowling workload and weeks a bowler was unable to bowl. the greatest reported risk factor to injury was past injury (74%), closely followed by recurrent injuries (61%). the data collected from the injury questionnaires indicated that the neglect of minor injuries such as cramp, fatigue, nodules and tendonitis predisposed the fast bowlers to more severe sprains and tears. junior bowlers are at greatest risk of sustaining an injury and then becoming re-injured in the same season, as they are still maturing and developing. 9 past injury has been identified as being a primary risk factor for injury and has shown that fast bowlers are the most susceptible to recurrences of past injuries of the same nature. 4,9 the initial onset of injury therefore should be prolonged for the longest possible time – particularly in a junior bowler. to delay the initial onset of injury, bowlers should be screened before each season and monitored continuously throughout the season. at the onset of injury the bowler should be adequately treated and rehabilitated to ensure full recovery. the most commonly injured were the knees (52%), followed by the lower back (43%), with most of these injuries occurring during t2 and t3. the primary mechanism of injury in this study was bowling (54%), other sport (41%), and other cricketing activities or random accidents (5%). bowling as a mechanism of injury showed a slightly higher incidence compared with data in the stretch and venter study. 9 in their study bowling accounted for 40% of injuries, followed by fielding at 33%, but overall the data demonstrate similarities with regard to injury mechanisms. bowlers exceeding bowling workload guidelines experienced the greatest number of recurring injuries, aggravated by continued bowling while injured. neglect to follow the recommended rest period between bowling days has been a significant contributing factor towards injury in the current study. the bowlers are continually repeating an explosive action that places great strain on their anatomy. this is compounded as the subjects have shown to be inadequately prepared physically. other risk factors that may have contributed in a multifactorial sense were ‘past injury’ and ‘injuries due to other sports’. mismanagement and neglect of previous injury may have a negative compounding effect on a bowler’s chances of incurring recurrent injuries. many of the bowlers reported that their injuries were due to other sports (41%), but that they had not sought medical intervention as the nature of the injury was not serious enough to require medical intervention. sportsmen often excel at more than one sport and consequently they become overwhelmed by the training demands of each sport. in the case of the young athlete the physical demands of each activity begin to take their toll on their immature bodies, resulting in overuse-type injuries. no individual risk factor was identified as playing a principal role in injury incidence. however, workload as a factor did have a higher statistical significance for increased injury risk. the significance of fitness, bowling technique and workload all played a role in injury occurrence. these variables, however, did not act alone but all had a contributing influence to the occurrence or re-occurrence of injuries at some stage. the bowling action alone would not have been so detrimental if the workloads were not so high, and workload would not have been as detrimental to a well-conditioned, uninjured bowler. in conclusion, the data in this study have highlighted many areas of concern regarding risk factors for fast-bowling injury. these data, coupled with other similar research done in this regard, should be made available and utilised by parents, coaches and cricketers to assist in educating them about the nature, incidence and possible risk factors for injury. in doing so injuries and/or risk of injury can be identified timeously to prevent the early onset of injury in the young, junior, elite fast bowler, thus prolonging their bowling careers. references 1. buckle g. fast bowlers need protection. cricket australia: (ca)’s inaugural cricket injury report. www.rediff.com/cricket/2004/jan/15bowl.htm (2004). 2. dennis r, finch cf, farhart pj. is bowling workload a risk factor for injury to australian junior cricket fast bowlers? br j sports med 2005; 39: 843-846. 3. finch c, elliott bc, mcgrath c. measures to prevent cricket injuries: an overview. sports med 1999; 28(4): 263-272. 4. nuttridge ga. the nature, prevalence and risk factors associated with pace bowling in men’s cricket: a prospective longitudinal study. unpublished masters dissertation, university of otago, 2001. 5. orchard j, james t. cricket australia injury report: official report. version 3.2. australia: university of new south wales, 2003. 6. smith c. why are fast bowlers getting injured? www.bbcnews.co.uk/sportsacademy/cricket/feature (2003). 7. stretch ra. incidence and nature of epidemiological injuries to elite south african cricket players. s afr med j 2001; 91(4): 336-339. 8. stretch ra. cricket injuries: a longitudinal study of the nature of injury to south african cricketers. br j sports med 2003; 37(3): 250-253. 9. stretch ra, venter djl. cricket injuries – a longitudinal study of the nature of injuries to south african cricketers. s afr med j 2005; 17(3): 4-9. 118 sajsm vol 20 no. 4 2008 sajsm vol. 25 no. 2 2013 47 original research objective. to investigate changes in the physical fitness characteristics of elite women’s rugby union players over a competitive season. methods. thirty-two elite women’s rugby union players, all members of the south african rugby union high performance squad, were sub-divided into 2 positional categories of 17 forwards and 15 backs, respectively, and assessed pre-, midand post-competition season. players underwent anthropometric (stature, body mass and sum of 7 skinfolds) and physical performance measurements (vertical jump, 10 m and 40 m sprint, 1 repetition maximum (1rm) bench press and multi-stage shuttle-run test). analysis. a 2-factor analysis of variance was used to evaluate differences in physical fitness variables between and within playing positions over the competition season (p<0.01). results. in both groups, no significant changes were detected in the sum of skinfolds, vertical jump height, 1rm bench press and multi-stage shuttle-run test scores throughout the season. however, sprint times (10 m and 40 m) significantly increased and then decreased for both groups between the early (preto mid-season) and later phases of the season (midto post-season), respectively. conclusion. the results suggest that, for improvement in physical fitness, players need to train at higher loads, especially in the preparatory phase. thereafter, they must take measures to actively maintain these gains throughout the competitive season. direct supervision of their conditioning should be encouraged. s afr j sm 2013;25(2):47-50. doi:10.7196/sajsm.371 changes in the physical fitness of elite women’s rugby union players over a competition season n m hene, ma (sport science); s h bassett, bsc (hons) (biokinetics), msc (sports science), phd department of sport, recreation and exercise science, university of the western cape, bellville, south africa corresponding author: n m hene (ncebahene@hotmail.com) the role of women within the rugby sphere has traditionally been one of provision rather than active participant.[1] over the past 2 decades, rugby union has grown unexpectedly as a female participative sport in australia, great britain, canada, the usa, new zealand and many other western and asian countries.[2] in 2000, when the south african rugby union (saru) accepted women’s rugby into the rugby fraternity, there were <10 clubs playing on a social basis. this inclusion culminated in the springbok women’s team participating in the 2006 international rugby board women’s world cup in canada.[3] rugby union is a contact sport in which players require high levels of physical fitness, composite of aerobic fitness and anaerobic endurance, muscle strength and power, speed, agility and body composition.[4] the seasonal nature of rugby imposes varied physical stresses that may compromise physical development.[5] hence, the capacity of elite players to acquire and maintain good physical fitness preand in-season, has become paramount.[6] male rugby players show the greatest improvement in strength, flexibility, aerobic fitness and reduction in skinfold thickness pre-season, before returning to baseline or maintaining values during a competitive season. [7-9] a reduction in muscular power, maximal aerobic fitness and increased skinfold thickness may also occur towards the end of the rugby season, due to low training loads, high match loads and injury rate.[8] however, little is known about the changes in physical fitness characteristics of women rugby players over a competitive season. several studies have described the anthropometric and physical performance characteristics of women’s rugby players; however, these studies were limited to a single fitness-testing session performed either pre-, midor post-season.[4,10-12] studies investigating changes in the physical fitness characteristics of women during a season for soccer,[13] handball[14] and hockey,[15] have reported desirable changes in body composition (a reduction in percentage body fat or skinfold thickness and an increase in lean muscle mass) and minimal change in body composition pre-[13,14] and in-season,[15] respectively. however, no stated changes in aerobic fitness[15] and muscle strength[16] were reported over the entire season. to date, no published study has monitored the physical fitness levels of women rugby union players over the course of a competition season; hence, the purpose of our study. this is important because the primary goal of pre-season training is to optimise fitness and enhance performance during in-season competition.[14] we hypothesised that the physical fitness characteristics of elite women’s rugby players would significantly improve from preto mid-season, and be maintained during the season, as is seen in men’s rugby.[17,18] methods research design and sample thirty-two women rugby players (mean age 27 years; standard deviation (sd) ±4; range 19 17), who were selected for the saru high performance squad of the 2010 women’s rugby world cup, were recruited for the study. players were selected from the 2008 interprovincial competition by national selectors appointed by the saru. the players were grouped according to forward (5 props, 2 hookers, 4 locks and 6 loose forwards) and back-line players (9 inside backs and mailto:ncebahene@hotmail.com 48 sajsm vol. 25 no. 2 2013 6 outside backs). prior to fitness testing, all players provided informed consent to study participation. ethical clearance to conduct the study was obtained from the university of the western cape. testing procedure anthropometric and physical performance measurements were conducted on 3 occasions during a 32-week season (april november 2009), which encompassed pre(weeks 1 12) and in-season periods (weeks 13 32), provincial games, and a 4-week international tour. the first test (t1) (may 2009) was performed 2 weeks after the start of pre-season; the second test (t2) (july 2009) in the middle of the competition season; and the third test (t3) (november 2009) 2 weeks after the end of the interprovincial league finals. players followed an individualised, but unsupervised, prescribed strength-and-conditioning programme, both preand in-season. pre-season, the programme required 3 resistance-training sessions and 2 high-intensity running sessions per week. in-season training was reduced to 1 2 resistance-training sessions and 1 high-intensity running session per week, plus match play. unfortunately, timing of the testing sessions could not be controlled and was not evenly distributed throughout the season, but rather scheduled around players’ work, study and playing commitments. physical fitness testing coincided with national training camps and all players were assessed on the first day of each camp by the sports physician and physiotherapist, who conducted a full medical examination and musculoskeletal screening. players with a medical condition or injury were excluded from the physical fitness assessment. although many physical attributes are required for successful performance in rugby union, only selected anthropometric and physical fitness tests were investigated, due to time constraints and player workload during the training camps (e.g. agility and anaerobic capacity were not assessed). similarly, the researchers did not assess lower-body strength due to the lack of identical strengthtesting equipment at all camps. the fitness-testing protocol was as follows: body mass was measured using a calibrated seca balance beam (0.1 kg accuracy); skinfold thickness was then measured at 7 sites (biceps, triceps, subscapular, suprailiac, medial calf, front thigh and abdominal) with harpenden skinfold callipers;[15] explosive leg power was tested using the vertec jump tester (sports imports, columbus, usa) and standard protocol;[16] 10 m and 40 m sprinting speed was evaluated with an electronic sprint timer with photo-electric sensors;[19,20] upper-body strength was evaluated with a 1 repetition maximum (1rm) bench press test (the final weight (in kg) successfully lifted was recorded as the absolute 1rm);[21] and finally, the progressive multi-stage shuttle-run test was conducted[22] (with the final shuttle achieved recorded as the aerobic fitness score). statistical analysis descriptive statistics were used to present the results. changes in physical fitness characteristics at the 3 time-points in the season between playing positions were compared using a 2-factor analysis of variance (anova), with the between-participants factor (player position) having 2 levels and the within-participants factor (time of testing) having 3 levels. the responses within participants were dependent; dependency was modelled using an unstructured correlation model. an interaction term for the 2 factors was included in the model. pairwise comparisons were done using least-squares means. due to the large number of tests conducted, a more stringent level of significance of p<0.01 was used rather than p<0.05. results body mass, skinfold thickness, muscular strength and power there was a significant decrease (p=0.007) in body mass among the backs from preto mid-season; no changes were observed from mid to post-season. there were no significant changes in body mass among the forwards throughout the season. over the 3 testing sessions, there were no significant changes in skinfold thickness among the backs; however, the sum of skinfolds in the forwards decreased significantly from preto post-season (p=0.001). no significant differences were noted for explosive leg power and muscular strength in either group. speed the times for the 10 m sprint, for both forwards and backs, were significantly slower (p<0.001) from preto mid-season, but improved significantly from midto post-season (p<0.001). furthermore, the forwards achieved significantly faster 10 m times post-season compared with pre-season (p<0.000), whereas there was no significant change in the backs’ sprint times over the same period. th e backs achieved significantly faster times from preto mid-season in the 40 m sprint (p<0.000), whereas the forwards’ speed did not change significantly during this period. however, from midto postseason, as well as from preto post-season, both groups’ times were significantly faster (p<0.001). aerobic fitness an assessment of the forwards’ aerobic fitness over the course of the season (multi-stage shuttle run), showed a significant decrease in the number of shuttles successfully completed from preto midseason (p=0.009), but a significant increase from midto post-season (p=0.001), with no significant change over the season. in contrast, no significant differences were observed among the backs. discussion in male rugby players, desirable changes in body composition (decrease in skinfold thickness) have been demonstrated pre-season when training volume was high.[5,7-9] furthermore, skinfold thickness was shown to be maintained throughout the competitive phase of the season when training loads were reduced, and match loads and injuries were at their highest.[7,10] there was no significant decrease in body mass, yet there was a significant decrease in skinfolds noted for the forwards in our study, contradictory to the results found among males. for the backs, there was a significant increase in weight from preto mid-season, with no significant change post-season and no significant change in the sum of skinfolds throughout the season. these results may reflect that women rugby players do not come into the pre-season at the optimal weight in the first place, with adaptations taking place to the training and match requirements at the beginning of the season. perhaps the training volume, intensity and/or frequency to elicit improvements in body-fat levels among the elite women’s rugby players prior to the season may have been inappropriate, or the players were simply not adhering to their preseason training programme as strictly as requested. sajsm vol. 25 no. 2 2013 49 the results obtained from both groups show that there were no changes in vertical jump performance over the season. the relatively modest change in jumping height within the participants could perhaps have been attributed to a greater focus on gym-based resistance training inseason, as well as a lack of plyometric training throughout the season. hoff et al.[23] suggested that in order to enhance vertical jumping ability, a well-designed training programme that includes short plyometric sessions should be implemented as part of the strengthand-conditioning programme. the sprint times for all players over 10 m and 40 m were contrary to previous research on senior[17] and junior[8] rugby league players, where times remained relatively unchanged throughout the season. the significant decrease in sprint performance noted for the backs between preand mid-season was most likely due to the significant increase in body mass during this time. although not significant, the forwards also increased in body weight during this time, which could have translated into their increased sprint times mid-season. this decrease in sprint times in the early stages of the season is of concern, because speed is an important indicator of a player’s athletic ability.[21] further research on the effects of concurrent training on the maintenance or improvement of speed in female rugby players would increase our understanding of the changes in physical fitness during the preparation phase. the goal of all preand in-season conditioning programmes for rugby players should be to maximise muscular fitness before the season and maintain the pre-season gains, respectively.[24] in this study, the 1rm bench press remained constant for backs and forwards preand in-season, despite the players being prescribed a periodised strength-and-conditioning programme during this time. it has been suggested that a lack of strength gains in professional athletes is likely due to concurrent training[24] and strength-training,[24,26] which may reduce the scope for further improvements. although this study did not research the training programme per se, the lack of improvement in upper-body strength results may have been due to a lack of direct supervision by a strength coach and/or possible insufficient training frequency and volume required to increase upper-body strength. this notion is supported by coutts et al.,[27] who noted that direct supervision of resistance training resulted in increased strength gains compared with unsupervised training. a number of studies of male rugby players have reported an increase in aerobic fitness during the preparatory phase of the season,[5,9,17] with a decrease observed towards the end of the season.[17] the significant improvements in fitness in the early stages of the season have been attributed to the high training loads experience during this period,[17] while reductions in aerobic fitness as the season progresses may be due to lower training loads and higher match loads and injury rates during this period.[28] in contrast to these findings, the current study showed no changes in aerobic fitness for backs over the entire season; however, the forwards followed a similar trend as seen in their male counterparts.[5,9,17] this lack of improvement in aerobic fitness during the preparatory phase in elite women’s rugby players may also be an indication of the lack of daily supervised training, which would otherwise result in greater training adherence and intensity.[25] previous studies of the physical fitness characteristics of women’s rugby players have been limited to a single fitness test performed during a competitive season.[4,10-12] our study is the first to document t ab le 1 . p hy si ca l fi tn es s da ta b y po si ti on fo r th e el it e w om en ’s ru gb y un io n pl ay er s pr e, m id a nd p os tse as on   v ar ia bl e fo rw ar ds (n =1 7) b ac ks (n =1 5) p re -s ea so n (n =1 7) m id -s ea so n (n =1 5) po st -s ea so n (n =1 4) pva lu e p re -s ea so n (n =1 5) m id -s ea so n (n =1 5) po st -s ea so n (n =1 2) pva lu e b od y m as s ( kg ), m ea n (± sd ) 77 .7 (± 13 .7 ) 79 .5 (± 14 .2 ) 78 .4 (± 11 .5 ) 62 .7 (± 6. 0) 63 .3 (± 6. 6) 63 .0 (± 6. 1) <0 .0 1* su m o f s ki nf ol ds (m m ), m ea n (± sd ) 13 3. 30 (± 33 .7 7) 13 4. 32 (± 50 .3 1) 11 6. 84 (± 20 .0 2) <0 .0 1‡ 10 6. 66 (± 19 .1 2) 90 .7 8 (± 21 .4 3) 10 2. 61 (± 23 .2 1) v er tic al ju m p (c m ), m ea n (± sd ) 37 .8 0 (± 5. 29 ) 38 .4 0 (± 5. 03 ) 39 .2 5 (± 5. 69 ) 44 .3 5 (± 5. 06 ) 44 .6 0 (± 5. 23 ) 47 .2 5 (± 2. 92 ) 10 m sp ee d (s ), m ea n (± sd ) 2. 05 (± 0. 15 ) 2. 18 (± 0. 10 ) 1. 99 (± 0. 09 ) <0 .0 1* ,† ,‡ 1. 90 (± 0. 07 ) 2. 08 (± 0. 08 ) 1. 90 (± 0. 04 ) <0 .0 1* ,† 40 m sp ee d (s ), m ea n (± sd ) 6. 48 (± 0. 32 ) 6. 63 (± 0. 27 ) 6. 41 (± 0. 03 ) <0 .0 1† ,‡ 5. 96 (± 0. 19 ) 6. 13 (± 0. 16 ) 5. 90 (± 0. 07 ) <0 .0 1* ,† 1r m b en ch p re ss (k g) , m ea n (± sd ) 62 .3 (± 1 6. 0) 55 .0 (± 12 .4 ) 58 .8 (± 12 .6 ) 55 .8 (± 9. 2) 57 .3 (± 7. 0) 54 .6 (± 6. 9) a er ob ic fi tn es s ( nu m be r o f s hu ttl es ), m ea n (± sd ) 65 .6 (± 27 .1 ) 53 .2 (± 18 .2 ) 62 .6 (± 13 .9 ) <0 .0 1* ,† 80 .4 (± 15 .3 ) 76 .4 (± 10 .7 ) 78 .8 (± 6. 7) 1r m = 1 re pe tit io n m ax im um . *s ig ni fic an t d iff er en ce b et w ee n pr e a nd m id -s ea so n. † s ig ni fic an t d iff er en ce b et w ee n m id a nd p os tse as on . ‡ s ig ni fic an t d iff er en ce p re a nd p os tse as on . 50 sajsm vol. 25 no. 2 2013 changes in physical fitness characteristics of women’s rugby players over the duration of a competitive season. this study has highlighted the lack of fitness in general in the south african women’s rugby team and the absence of improvement over the season that would be expected of a men’s side. conclusion our study revealed no significant improvements in skinfold thickness, explosive leg power, upper-body muscular strength and aerobic fitness within forwards and backs between preand mid-season. this suggests that the conditioning programme of the players throughout the season was inappropriate, or that their adherence to the prescribed programme was inadequate, or both. it is suspected that female players do not adhere to unsupervised training programmes; direct daily training supervision, similar to that of their male counterparts, is recommended, and strength-and-conditioning coaches should be more directly involved with player preparation. this is not an easy task, as female rugby players are currently not exposed to the same organised club, league, training structures, etc. as their male counterparts, and do not have access to similar infrastructure, especially well-equipped training facilities. to improve the physical fitness of women rugby players, we suggest the implementation of supervised strength-and-conditioning sessions. however, further studies are required to determine the appropriate training stimulus thus required. coaches need to be cognizant of this general lack of fitness, which increases the risk of injury. substantial resources and emphasis should be directed towards women’s rugby players achieving pre-determined fitness levels at various age categories, as with the men’s game, to allow more effective toleration of the physical demands of competition. however, this is a double-edged sword, as there are perhaps not enough women playing the game at this point to be so selective. we recommend that existing men’s rugby structures should assist the women’s game more, especially as rugby sevens will debut at the 2016 olympic games. as women’s rugby is currently developing rapidly the world over, south africa must look at these issues in order to compete internationally. lastly, much more research needs to be conducted on this form of the game. references 1. haynes j, miller j. women playing rugby, an 'old boys game': beyond the social expectations. http://www.aare.edu.au/01pap/mil01183.htm (accessed 12 october 2009). 2. chu mml, leberman si, howe bl, bachor dg. the black ferns: the experiences of new zealand's elite women rugby players. j sport behav 2003;26(2):109. 3. international rugby board. sa rugby union. http://www.irb.com/unions/ union=11000034/index.html (accessed 12 october 2009). 4. hene nm, bassett sh, andrews bs. physical fitness of elite women’s rugby union players. afr j phys health educ recr dance 2011;17(suppl 1):1-8. 5. holmyard dj, hazeldine rj. seasonal variations in the anthropometric and physiological characteristics of international rugby union players. in: reilly t, ed. science and football. london: e & fn spon, 1993:21-26. 6. caldwell bp, peters dm. seasonal variation in physiological fitness of a semiprofessional soccer team. j strength cond res 2009; 25(5):1370-1377. [http://dx.doi. org/10.1519/jsc.0b013e3181a4e82f ] 7. duthie gm, pyne db, hopkins wg, livingstone s, hooper sl. anthropometry profiles of elite rugby players: quantifying changes in lean mass. br j sports med 2006;40(3):202-207. [http://dx.doi.org/10.1136/bjsm.2005.019695] 8. gabbett tj. physiological and anthropometric characteristics of junior rugby league players over a competitive season. j strength cond res 2005;19(4):764-771. [http:// dx.doi.org/10.1519/00124278-200511000-00007] 9. tong rj, mayes r. the effect of pre-season training on the physiological characteristics of international rugby union players. in reilly t, bangsbo j, hughes m, eds. science and football iii: proceedings of the third world congress of science and football. london: e & fn spon, 1995:92-102. 10. gabbett tj. physiological and anthropometric characteristics of elite women rugby league players. j strength cond res 2007;21(3):875-881. [http://dx.doi. org/10.1519/00124278-200708000-00038] 11. kirby wj, reilly t. anthropometric and fitness profiles of elite female rugby union players. in: reilly t, ed. science and football. london: e & fn spon, 1993:62-72. 12. quarrie kl, handcock p, waller ae, et al. the new zealand rugby injury and performance project. iii. anthropometric and physical performance characteristics of players. br j sports med 1995;29(4):263-270. [http://dx.doi.org/10.1136/ bjsm.29.4.263] 13. clark m, reed db, crouse sf, armstrong rb. preand post-season dietary intake, body composition and performance indices of ncaa division 1 female soccer players. int j sport nutr exerc metab 2003;13(3):303-319. 14. granados c, izquierdo m, ibáñez j, ruesta m, gorostiaga em. effects of an entire season on physical fitness in elite female handball players. med sci sports exerc 2008;40(2):351-361. [http://dx.doi.org/10.1249/mss.0b013e31815b4905] 15. astorino ta, tam pa, rietschel jc, johnson sm, freedman tp. changes in physical fitness parameters during a competitive hockey season. j strength cond res 2004;18(5):850-854. [http://dx.doi.org/10.1519/00124278-200411000-00029] 16. ross wd, marfell-jones mj. kinanthropometry. in: macdougall jd, wenger ha, green hj, eds. physiological testing of the high-performance athlete. champaign, il: human kinetics, 1991:223-308. 17. gabbett tj. changes in physiological and anthropometric characteristics of rugby league players during a competitive season. j strength cond res 2005;19(2):400-408. [http://dx.doi.org/10.1519/00124278-200505000-00027] 18. gabbett tj, king t, jenkins d. applied physiology of rugby league. sports med 2008; 38(2):119-138. [http://dx.doi.org/10.2165/00007256-200838020-00003] 19. baechle tr, earle rw, wathan w. resistance training. in: baechle tr, earle rw, eds. essentials of strength training and conditioning. champaign, il: human kinetics, 2000:381-412. 20. durandt j, du toit s, borrensen j, et al. fitness and body composition profiling of elite junior south african rugby players. south african journal of sports medicine 2006;10(3):38-45. 21. logan p, fornasiero d, abernethy p, lynch k. protocols for the assessment of isoinertial strength. in: gore cj, ed. physiological tests for elite athletes. champaign, il: human kinetics, 2000:200-221. 22. léger la, lambert j. a maximal multistage 20 m shuttle run test to predict vo2 max. eur j appl physiol occ phys 1982;49:1-2. [http://dx.doi.org/10.1007/bf00428958] 23. hoff j, kemi oj, helgerud j. strength and endurance differences between elite and junior elite hockey players: allometric scaling of strength measurement to body size. eur j appl physiol 2005;102:739-745. 24. hrysomallis c. upper body strength and power changes during a football season. j strength cond res 2010;24(2):557-559. [http://dx.doi.org/10.1519/ jsc.0b013e3181c09c9c] 25. kraemer wj, french dn, paxton nj, et al. changes in exercise performance and hormonal concentrations over a big ten soccer season in starters and nonstarters. j strength cond res 2004;18(1):121-128. [http://dx.doi.org/10.1519/00124278200402000-00018] 26. baker d. the effects of an in-season of concurrent training on the maintenance of maximal strength and power in professional and college-aged rugby league football players. j strength cond res 2001;15(2):172-177. [http://dx.doi. org/10.1519/00124278-200105000-00004] 27. coutts aj, murphy aj, dascombe bj. effect of direct supervision of a strength coach on measures of muscular strength and power in young rugby league players. j strength cond res 2004;18(2):316-323. [http://dx.doi.org/10.1519/00124278200405000-00021] 28. gabbett tj, kelly jn, sheppard jm. speed, change of direction speed, and reactive agility of rugby league players. j strength cond res 2008;22(1):174-181. [http:// dx.doi.org/10.1519/jsc.0b013e31815ef700] http://www.aare.edu.au/01pap/mil01183.htm http://www.irb.com/unions/ http://dx.doi.org/10.1519/jsc.0b013e3181a4e82f] http://dx.doi.org/10.1519/jsc.0b013e3181a4e82f] http://dx.doi.org/10.1136/bjsm.2005.019695] http://dx.doi.org/10.1519/00124278-200511000-00007] http://dx.doi.org/10.1519/00124278-200511000-00007] http://dx.doi.org/10.1519/00124278-200708000-00038] http://dx.doi.org/10.1519/00124278-200708000-00038] http://dx.doi.org/10.1136/bjsm.29.4.263] http://dx.doi.org/10.1136/bjsm.29.4.263] http://dx.doi.org/10.1249/mss.0b013e31815b4905] http://dx.doi.org/10.1519/00124278-200411000-00029] http://dx.doi.org/10.1519/00124278-200505000-00027] http://dx.doi.org/10.2165/00007256-200838020-00003] http://dx.doi.org/10.1007/bf00428958] http://dx.doi.org/10.1519/jsc.0b013e3181c09c9c] http://dx.doi.org/10.1519/jsc.0b013e3181c09c9c] http://dx.doi.org/10.1519/00124278-200402000-00018] http://dx.doi.org/10.1519/00124278-200402000-00018] http://dx.doi.org/10.1519/00124278-200105000-00004] http://dx.doi.org/10.1519/00124278-200105000-00004] http://dx.doi.org/10.1519/00124278-200405000-00021] http://dx.doi.org/10.1519/00124278-200405000-00021] http://dx.doi.org/10.1519/jsc.0b013e31815ef700] http://dx.doi.org/10.1519/jsc.0b013e31815ef700] introduction the occurrence of home advantage in sport is generally well documented and has been shown to exist in a variety of sports and events.1-9 however, the olympic games is the only multi-sport competition of global significance in which the phenomenon has been extensively examined.1,2,9 the commonwealth games, often referred to as the ‘friendly games’, is arguably the second most significant multi-sport international sporting competition, behind the olympics. furthermore, some of the sports historically contested in the commonwealth games (e.g. lawn bowls) are not part of the olympic programme. therefore the consideration of the commonwealth games provides a different dimension to home advantage research. given that 2010 is a commonwealth games year, now is perhaps an opportune time to investigate how host nations have historically performed in the event. the ultimate aim of this article is to understand whether or not hosting the commonwealth games might lead to a competitive advantage in performance. we also investigate the role of travel in shaping performance in the commonwealth games. the commonwealth is a voluntary alliance of 53 nations spread across the globe. sport is a key part of the commonwealth’s identity, and commonwealth heads of government have recognised the benefits of physical activity and the importance of sport as an effective instrument for social and economic development (see: http://www.thecommonwealth.org/subhomepage/143537/). the prominence of sport within the commonwealth brand is expressed via the commonwealth games held every four years. although there are 53 commonwealth nations, there are at present 71 commonwealth games associations (cgas) that can enter a team in the commonwealth games, as one nation can have multiple cgas. for example, the uk is a single commonwealth nation but consists of seven cgas – england, guernsey, isle of man, jersey, northern ireland, scotland and wales – all of which compete in the commonwealth games as separate nations. table i illustrates the evolution of the commonwealth games. the inaugural edition took place in hamilton, canada, in 1930, with 11 countries and 400 athletes contesting 6 sports. since then there have been 17 editions of the event, with the most recent being in melbourne, australia, in 2006. attendance at each edition of the commonwealth games has steadily increased to the point that in 2002 all commonwealth nations were represented in manchester, england. as the number of nations taking part has increased, so too have the number of athletes, events and disciplines. the number of teams competing in the commonwealth games is dependent upon the number of nations in the commonwealth itself as, from year to year, nations are admitted and suspended for various reasons. the very early editions of the commonwealth games (1930 1938) were characterised by few participant nations and a limited number of sports. consequently, and also because the commonwealth games were suspended around the time of world war ii, the research concentrates on the post-war editions of the event, i.e. from 1950 to 2006. it may be argued that competition in the commonwealth games has increased over time by virtue of more nations and more athletes taking part. to illustrate this point, the athlete to event ratio has increased from 6.70 (590/88) in 1950 to 16.53 (4 049/245) in 2006, which indicates that the intensity of competition has increased during this period. over and above the typical motives cited by nations original research article home advantage in the commonwealth games abstract objectives. research examining the phenomenon of home advantage in international multi-sport competitions is limited to the olympic games. this paper investigates the prevalence of home advantage in the commonwealth games. the paper also explores the relative impact of travel on performance in the commonwealth games. methods. home and away performances for all previous host nations were examined using the standardised measure of market share, regarded by recent european studies as the most robust indicator of a nation’s sporting performance. for each host nation, the host effect was calculated as the difference between their average home and away performances. furthermore, the market share values for each host nation were analysed relative to the distance travelled by them (in terms of the number of time zones crossed) in every edition. this exercise was extended to all nations that have sent a team to the commonwealth games in the post-war era. results. the research found that, with the exception of england, all previous host nations experienced a positive host effect in the commonwealth games. furthermore, for the majority of nations it was found that performance is negatively correlated with distance travelled. in other words, as distance travelled increases, performance deteriorates. conclusion. the findings suggest that future host nations of the event can expect to achieve an elevated level of performance when competing on home soil. this may in part be attributable to their athletes not having travel outside their own time zone. direction for future research is offered. correspondence: gm ramchandani a118 collegiate hall, collegiate crescent sheffield s10 2bp tel: +44 (0) 114 225 5461 e-mail: g.ramchandani@shu.ac.uk girish m ramchandani (msc) darryl j wilson (msc) sport industry research centre, sheffield hallam university, sheffield, uk 8 sajsm vol 22 no. 1 2010 sajsm vol 22 no. 1 2010 9 for staging an event of this magnitude (e.g. economic, regeneration, international recognition, socio-cultural, sport development, etc.), hosting the commonwealth games could also be a strategic approach to combat the increase in competition if home advantage is likely – at least as a short-term solution. methods the method used to conduct this research involved secondary analysis on the results database of the commonwealth games from 1950 to 2006. the event takes place every 4 years and thus the results are based on 15 editions of the event. the results data for each edition were sourced from the official commonwealth games website (http://thecgf.com/games/games_index.asp?linkresults=1). in total eight nations were eligible for inclusion in the home advantage calculations on account of having hosted the event on at least one occasion since 1950, as identified in table i. eligible nations included australia, canada, new zealand (each with 3 home editions), scotland (2 home editions), england, jamaica, malaysia and wales (1 home edition each). the commonwealth games medal table ranks participating nations in descending order of gold medals won, although such tables are not officially recognised as being an order of merit. there exist alternative approaches to performance measurement in international sport and different performance measurement systems can give conflicting diagnosis of a nation’s performance. recent european studies10,11 argue that the most robust indicator of nations’ sporting performance is ‘market share’– a standardised measure of total achievement whereby the total medals won in an event are converted into points (gold = 3, silver = 2 and bronze = 1) and the points won by a given nation are subsequently expressed as a percentage of the total points available. for example, if a nation wins 20 gold medals (60 points), 15 silver medals (30 points) and 10 bronze medals (10 points) then the total number of points won is 100 (60 + 30 + 10). assuming the total number of points available is 1 000 then its market share would be 10% (i.e. 100/1 000). market share calculations were undertaken for all host nations across each edition of commonwealth games between 1950 and 2006. for each host nation, home market share performances were then compared against their away market share performances to assess whether home advantage was prevalent. in order to test whether travel had an impact on performance, the market share values for each host nation were examined relative to the distance travelled by them (in terms of the number of time zones crossed) in every edition. the analysis revealed the nature and strength of the relationship between host nation performance and travel in the commonwealth games. this exercise was subsequently extended to all nations that have sent a team to the commonwealth games in the post-war era. results the overall home and away performances for all host nations are summarised in table ii, using the standardised measure of market share. all things being equal, it might be expected that a nation’s average performance at home is comparable with its average performance away from home. however, for seven of the eight nations in table ii market share is higher when competing on home soil, as indicated by a positive host effect for these nations. the magnitude of home advantage, where prevalent, varies by nation, ranging from 0.3 table i. growth of the commonwealth games year host nations sports events athletes 1930 canada 11 6 59 400 1934 england 16 6 68 500 1938 australia 15 7 71 464 1950 new zealand 12 9 88 590 1954 canada 24 9 91 662 1958 wales 35 9 94 1 122 1962 australia 35 9 104 863 1966 jamaica 34 9 110 1 050 1970 scotland 42 9 121 1 383 1974 new zealand 38 9 121 1 276 1978 canada 46 10 128 1 474 1982 australia 46 10 142 1 583 1986 scotland 26 10 163 1 662 1990 new zealand 55 10 204 2 073 1994 canada 63 10 217 2 557 1998 malaysia 70 15 213 3 633 2002 england 72 17 281 3 679 2006 australia 71 16 245 4 049 table ii. host nation performance in the commonwealth games 1950 2006 nation overall home away host effect editions average (%) editions average (%) editions average (%) % points australia 15 26.9 3 30.2 12 26.0 4.2 england 15 21.4 1 18.7 14 21.8 (3.1) canada 15 16.2 3 21.3 12 15.0 6.3 new zealand 15 6.2 3 10.4 12 5.3 5.1 scotland 15 3.7 2 5.6 13 3.4 2.2 wales 15 2.5 1 2.8 14 2.5 0.3 malaysia 13 2.0 1 5.3 12 1.6 3.7 jamaica 13 1.7 1 2.4 12 1.6 0.8 host effect = home average (%) minus away average (%). percentage points for wales to 6.3 percentage points for canada. in the analysis, england was the only nation for which an adverse host effect was observed. the lack of home advantage in the case of england masks the nation’s superior performances in the editions held by its fellow uk home nations and immediate neighbours – scotland and wales. to illustrate this point, the average market share for england in the commonwealth games held in the uk (at home, in scotland and wales) is 26.7% and 20.7% when held elsewhere. table iii highlights the ‘best’ and ‘worst’ performances for each host nation and pinpoints the location of such performances in terms of home, away and neighbour editions. the concept of neighbour edition is introduced to account for the geographical proximity in the case of uk home nations of england, scotland and wales and possibly for other host nations. for this purpose, a neighbour was considered to be any nation sharing the same time zone with the host nation. according to table iii, the most productive market share performance for five of the eight host nations in the commonwealth games coincided with their home edition. furthermore, two of the three instances where nations did not reach their highest level of performance at home occurred on neighbouring soil – performances for both england and wales peaked in scotland. furthermore, the lowest market share returns for all host nations are confined to the ‘away’ column in table iii. therefore, without exception, the least favourable performance was witnessed when not competing at home or in the same time zone. together these findings draw attention to the implications of competing at home and, to a lesser extent, nearer to home. using the number of time zones crossed as an indicator of distance travelled to the host nation, it was possible to plot each nation’s performance against the corresponding travel factor (time zone difference from the host nation) across every edition. the exercise revealed that performance was negatively correlated with travel for all host nations. in other words, as distance travelled increases, performance deteriorates. the coefficient of correlation (r) values are presented in fig. 1. in order to test whether this finding was limited to host nations or part of a more common phenomenon, we repeated the exercise for all 78 nations that have contested the commonwealth games since 1950. some territories have subsequently merged whilst others are no longer part of the commonwealth alliance. for the purpose of this research, 23 nations were exempt from the analysis on the basis that they only contested one edition of the event and therefore there is no alternative point of reference available for these nations against which to relate their performance with travel to the host location (e.g. belize, brunei, gibraltar and sierra leone). in this regard, the findings relate to 55 ‘eligible’ nations. overall, the analysis revealed an inverse association (r<0) between distance travelled and performance for 38 (69%) out of the 55 nations. in other words, for the majority of nations, success in the event diminishes with travel. the magnitude of the correlation varies by nation and by broad geographic region. for example, the table iii. host nation performance matrix nation best performance (market share) worst performance (market share) home % neighbour % away % home % neighbour % away % australia 34.3 18.6 canada 29.5 6.8 england 29.4 15.0 jamaica 3.1 0.5 malaysia 5.3 0.2 new zealand 18.4 3.3 scotland 6.1 1.5 wales 4.0 0.4 fig. 1. travel versus performance in the commonwealth games (r values)                                                      fig. 1. travel versus performance in the commonwealth games (r values). 10 sajsm vol 22 no. 1 2010 sajsm vol 22 no. 1 2010 11 finding r<0 was more widespread among commonwealth nations from africa (14/18 nations, 78%) and europe (7/9 nations, 78%) relative to those from americas/caribbean (8/12 nations, 67%) and asia/oceania (9/16 nations, 56%). the performance for india, the host of the 2010 commonwealth games, was also found to be negatively correlated with distance travelled (r=-0.40). thus, in theory not having to travel abroad or outside its own time zone to compete could make a positive contribution to india’s performance in 2010. nations that did not exhibit an inverse relationship between travel and performance (i.e. where r>0) were found to be generally those with relatively modest success in the commonwealth games (e.g. cayman islands, jersey, norfolk island and st. vincent and the grenadines). discussion the first key finding from the research was that, with the exception of england, all previous host nations experienced a positive host effect in the commonwealth games. it is difficult to comment on the statistical significance of these findings because of the size of the data set involved. the analysis is limited to at most 15 editions (or observations) for a host nation. also, nations inevitably compete away from home more often than they do at home. this in turn creates a disparity between the number of home and away observations for each nation in the sample. for example, australia has only three observations for home performance but twelve observations for away performance. despite the limitations of the data, in descriptive terms, there is evidence of nations generally performing better when they have hosted the commonwealth games. if we regard average away performance as a measure of nation quality then there appears to be no systematic relationship between the relative quality of a host nation and the extent of the home advantage. for example, both canada and new zealand benefit more at home than australia. similarly, the home advantage experienced by malaysia and jamaica is greater than that of wales, but lower than canada, new zealand and australia. in other words, traditionally stronger nations in the commonwealth games do not necessarily benefit from greater home advantage. as to why such home advantage may exist, there are generally three factors that are perceived to be at work: the influence of the home crowd, home athletes’ familiarity with local conditions, and the effects of travel.8,12-20 the last of these factors is particularly pertinent in the context of the commonwealth games where international travel is involved that can sometimes span several time zones. the research has shown that, as a general rule of thumb, a nation’s performance in the commonwealth games progressively deteriorates the further its athletes travel away from their own time zone. a possible explanation for this finding is ‘jet lag’. previous research18 indicates that the severity of jet lag and subsequent recovery is a function of the number of time zones crossed. from a policy standpoint, the findings from the research should enable non-host nations to set pragmatic aspirations for success in the commonwealth games, allowing for any ‘performance loss’ associated with travel to the host location, particularly when the event is held in a different time zone. yet another candidate for home advantage in the commonwealth games is strategic in nature. this relates to the level of influence that a host nation can exert over the portfolio of sports, and the number of events contested within those sports, at its home edition. at present, the commonwealth games programme consists of a minimum of 10 sports, all which are mandatory. article 21 of the commonwealth games federation constitution (http://thecgf.com/ about/constitution.pdf) states that a candidate city has the option to select up to seven further disciplines from a predetermined list of sports. thus, host nations may opt to put forward sports and events that provide them with the best opportunity to win medals. concurrently, organising committees may consciously minimise or omit disciplines in which competitor nations have a proven track record of success. this presents an area for future research to investigate how well host nations perform in optional sports rather than those that are mandatory. much of the media coverage surrounding the 2010 commonwealth games in delhi has focussed on the city’s preparation for, and capability of, staging the event. this issue has been further flagged following the recent abandonment of the fifth one day international cricket match between india and sri lanka in delhi due to an unfit pitch. regardless of how well delhi is progressing towards ensuring the successful delivery of the commonwealth games, on the field it is reasonable to expect an elevated level of performance from indian athletes given the evidence presented in this paper. references 1. balmer nj, nevill am, williams am. home advantage in the winter olympics (1908-1998). j sports sci 2001;19:129-139. 2. balmer nj, nevill am, williams am. modelling home advantage in the summer olympic games. j sports sci 2003;2:469-478. 3. balmer nj, nevill am, lane am. do judges enhance home advantage in european championship boxing? j sports sci 2005;23:409-416. 4. bray sr, carron av. the home advantage in alpine skiing. australian journal of science and medicine in sport 1993;25:76-81. 5. koning rh. home advantage in speed skating: evidence from individual data. j sports sci 2005;23:417-427. 6. mcandrew f. the home advantage in individual sports. journal of sports psychology 1993;133:401-403. 7. nevill am, balmer nj, winter em. why great britain‘s success in beijing could have been anticipated and why it should continue beyond 2012. br j sports med 2009;43: 1108-1110. 8. nevill am, holder rl. home ground advantage in sport: an overview of studies on the advantage of playing at home. sports med 1999;28:221236. 9. uk sport. home advantage: the performance benefits of hosting major sporting events. uk sport london; 2009. 10. de bosscher v, de knop p, van bottenburg m, shibli s. a conceptual framework for analysing sport policy factors leading to international sporting success. european sport management quarterly 2006;6:185-215. 11. de bosscher v, bingham j, shibli s, van bottenburg m, de knop p. the global sporting arms race: an international comparative study on sports policy factors leading to international sporting success. meyer & meyer sport (uk) ltd. oxford; 2008. 12. agnew jc, carron av. crowd effects and the home advantage. international journal of sport behavior 1994;25:53-62. 13. carron a, loughhead t, bray s. the home advantage in sport competitions: courneya and carron’s (1992) conceptual framework a decade later. j sports sci 2005;23:395-407. 14. courneya ks, carron av. effects of travel length of home stand/road trip on the home advantage. journal of sport and exercise psychology 1991;13:42-49. 15. du preez m, lambert mi. travel fatigue and home ground advantage in south african super 12 rugby teams. south african journal of sports medicine 2007;19:20-22. 16. jehue, r, street, d, huizenga r. effect of time zone and game time changes on team performance: national football league. medicine & science in sports & exercise 1993;25:127-131. 17. nevill am, balmer nj, williams am. the influence of crowd noise and experience upon refereeing decisions in football. psychology of sport and exercise 2002;3:261-272. 18. pace a, carron av. travel and the home advantage. canadian journal of sports sciences 1992;17:60-64. 19. reilly t, waterhouse j, edwards b. jet lag and air travel: implications for performance. clin sports med 2005;24:367-380. 20. waterhouse j, reilly t, edwards b. the stress of travel. j sports sci 2004;22:946-966. original research 1 sajsm vol. 29 2017 the use of negative pressure wave treatment in athlete recovery a jansen van rensburg1, msc, d c janse van rensburg1, md, h e van buuren2, msc (exerc physiol), c c grant1, phd, l fletcher3, phd 1section sports medicine, faculty of health science, university of pretoria, pretoria, south africa 2institute for sports research, university of pretoria, pretoria, south africa 3department of statistics, faculty of natural & agricultural sciences, university of pretoria, pretoria, south africa corresponding author: a jansen van rensburg (audrey.jansenvanrensburg@up.ac.za) lower body negative pressure (lbnp) treatment, also known as intermittent vacuum therapy, was developed for astronauts, to maintain the arterial blood supply of the lower body and compensate for weightlessness. due to the low gravity in space, autonomic cardiovascular control deteriorates and orthostatic tolerance is re-established by means of lbnp therapy after exploration flights.[1] designed to act as an external heart for the lower body, the lbnp device generates a rhythmic alternating pressure of intermittent waves of negative pressure (lower pressure), and normal pressure (atmospheric pressure). as described in available literature this mechanism causes strong capillary dilation and compression pulsations[2] through which blood circulation and perfusion in the lower limbs are increased.[3] arteries dilate as oxygen (o2)-rich blood and nutrients are drawn into the tissue (hypobaric), resulting in a higher available concentration of o2 and supplements in the muscle,[4] followed by an atmospheric pressure phase, a relief of the reflux, when carbon dioxide (co2) and metabolic waste products are pressed back into the upper body through the circulatory system and the lymphatic vessels.[5] this application of sub-atmospheric pressure to the lower portion of the body (below the iliac crest) consequently enhances the baroreflex that assists in maintaining blood pressure during orthostatic stress.[1,2] in clinical applications, the use of negative pressure has been indicated as an effective modality.[4,6] a study by schneider et al.[7] indicated an improvement in heart rate and blood pressure responses observed with the application of lbnp after 15 days of bed rest. following excessive training, athletes often experience symptoms of discomfort, muscular soreness and stiffness within 12–24h, which can contribute to the development of muscular fatigue resulting in deteriorating performance.[8,9] delayed onset muscle soreness (doms) is an inflammatory reaction caused by the micro-damage of primary muscle. sports massage is a popular treatment and a frequently applied intervention; however, evidence to support its efficacy as a technique to enhance recovery is still being explored.[10] appropriate methods of recovery are, however, essential to restore an athlete’s physiological and psychological capacities. prompt and sufficient recovery can also improve performance by enhancing training quality and tolerance to the training load, as well as improving the athlete’s adaptation to training. without proper recovery following multiple training sessions or competitions, an athlete increases the risk for poorer performance and overuse injuries.[8,10] mimicking sports massage by stimulating the circulatory system and lymphatic vessels, lbnp is claimed to play a vital role in the recovery of the athlete in order to maximise athletic performance in competitive sport. the endurance capacity in athletes differs, with highly trained athletes performing at a higher maximal oxygen uptake, presenting with minimum lactate accumulation. during exercise of increasing intensity, an increase in blood lactate concentration is an indication of a rise in glycogen metabolism within the muscle. however, the initial increase in blood lactate concentration implies the net result of lactate production in the muscle, and reflects that the appearance rate of lactate in the blood is higher than the disappearance rate (the result of a balance between the rate of production and removal).[11,12] this is referred to as the lactate threshold and is background: athletes need to recover fully to maximise performance in competitive sport. athletes who replenish more quickly and more efficiently are able to train harder and more intensely. elite athletes subjectively report positive results using lower body negative pressure (lbnp) treatment as an alternate method for rapid recovery, restoring and improving their impaired physical state. objective data on the efficacy are lacking. objectives: to investigate the effect of intermittent vacuum therapy on accelerating acute recovery following an athlete’s normal daily training schedule of strenuous exercise. objective measurements of biological markers of muscular fatigue were used to assess recovery. methods: twenty-two male cricket players in a randomised cross-over study were divided into a treatment and control group respectively. following a one-hour high-intensity gym session, the treatment group received three 30-minute lbnp exposure sessions over three consecutive days (0, 24 and 48 hours). blood lactate and creatine kinase biomarkers were collected to measure the recovery process. after 14 days groups were crossed over and the trial repeated. results: heart rate and blood pressure decreased noticeably during treatment, reverting to baseline levels after treatment. lactate concentrations decreased in both groups after exercise termination; significantly more in the treatment (0.57±0.23 mmol/l) than control group (0.78±0.22 mmol/l), p<0.001). creatine kinase (ck) was similar in both groups. athletes’ subjective assessments of recovery rated moderately high. conclusion: lbnp therapy applied as treatment during routine schedule may have a systemic effect in lowering serum lactate levels, but not ck levels. enhanced recovery of athletes is still unconfirmed. keywords: lower body negative pressure, athlete restoration, athlete performance, athlete rehabilitation, athlete recuperation s afr j sports med 2017;29:1-7. doi: 10.17159/2078-516x/2017/v29i0a1544 mailto:audrey.jansenvanrensburg@up.ac.za http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1544 original research sajsm vol. 29 2017 2 considered to be a good predictor of endurance exercise performance. the lactate threshold is often used to prescribe training intensities, based on the relationship between blood lactate levels and heart rate. in the same way, active recovery after strenuous exercise will clear the accumulated blood lactate levels faster than passive recovery. more so in an intensity-dependent manner, with maximum blood lactate clearance occurring with active recovery close to the lactate threshold.[12,13] the severity of muscle damage and injury is frequently monitored by blood serum ck enzyme activity levels.[14] although debated by researchers, lactate concentration and blood serum ck activity levels are implemented as biomarkers in measuring the recovery process that is crucial for successful endurance capacity and sport performance.[12,13,14] hormonal changes in the body are involved in regulating various physiological functions, and when activated are known to improve mental function and willpower, thus automatically increasing the subjective well-being of an individual.[15] the increased blood circulation in the entire body and brain achieved by the vacuum effect of the lbnp device may hypothetically also increase oxygen circulation and influence hormone levels and their release in the blood to enhance a feeling of perceived recovery experienced by the athletes, with the magnitude of improvement remaining of a perceptive nature. lbnp therapy is becoming popular through the promise of an innovative to optimise and accelerate sports recovery, increase physical performance and reduce breaks from training, with very little confirmed evidence. the objective of this study was to assess if intermittent negative pressure therapy applied to the lower body of athletes will affect known measures of muscular recovery and result in faster recovery time and recuperation. methods study design a randomised cross-over study design with repeated measures was performed to determine the effect negative pressure wave treatment has on the recovery of cricketers. an information letter with a full explanation regarding the nature of the study was given to all participants, and informed written consent forms were collected from each candidate prior to the study. the study protocol was approved by the ethics committee of the university of pretoria, south africa (approval number 352/2013). participants and selection criteria twenty-two healthy male cricket players based at the tuks cricket academy, at the high performance centre of the university of pretoria, south africa, were invited to participate. players were randomly assigned to one of two groups and evaluated. after the second week the participants were crossed over and the study repeated over the following two weeks. participant exclusion criteria included cardiovascular diseases, hypotony with proneness to collapse, diabetes, recent phlebotrombosis (<eight weeks), the risk of thromboembolism and smoking. participants were instructed to refrain from drinking alcohol, and consuming caffeine products 24 hours prior to each study session. study procedure all participants documented their personal information and history before the start of the study. the age, body mass, height and body mass index (bmi) of each athlete were recorded at the start of the study. each player participated in the cross-over design during the four week study period: once in the treatment group (receiving lbnp treatment; ext) and once in the control group (not receiving lbnp treatment; exc). the two applications were separated by a washout period of 14 days. each trial assessment was completed over three consecutive days and followed the same routine physical, physiological and treatment conduct as illustrated in figure 1. the cricket players continued to follow their regular weekly physical training programme consisting of seven hours conditioning and 10 hours cricket specific skills, with one competitive match on weekends, throughout the study period. protocol on the first day of the trial (figure 1) baseline physiological measurements (heart rate (hr); blood pressure (bp); blood oxygen saturation (spo2)) and blood samples (lactate (lac); creatine kinase (ck)) were collected from the participating athletes pre-exercise. participants then completed a one hour high-intensity gym session comprising of weighted exercises and plyometric upper and lower limb training. directly after the exercise session, physiological measurements and blood sample collection were repeated. players were randomly assigned to either receive one 30 minute lbnp treatment session (ext) or remain seated in the treatment room with no exposure (exc). a questionnaire (based on an ordinal rating scale of one to five) was completed by each player before and after every lbnp treatment session, to quantify their perceived recovery state (table 1). normal training proceeded in the afternoon and the players returned on day two and day three during which the same athletes once more received either a treatment session or remained unexposed. physiological measurements and blood samples were collected daily before and during each treatment session, for both the treatment (ext) and control (exc) participants. treatment sessions were labelled as: 0 hours after, 24 hours after and 48 hours after intense training. lbnp vacuum therapy the lbnp device for intermittent vacuum therapy comprises of a cylinder-shaped chamber into which the lower body of the athlete is placed. the athlete lies on his back, his legs and lower body up to the iliac crest bone, inside the chamber. the chamber, enfolding the lower body of the athlete, is sealed by means of a diaphragm (iris seal) around the waist. alternating negative and normal pressure is generated in the chamber by a vacuum pump. the device generates rhythmic interchanging pressure waves of normal pressure (atmospheric pressure) and negative pressure (lower pressure) at alternating pulsations. a vacuum treatment with negative pressure setting of 68 mbar was regulated, with an atmospheric pressure:negative pressur original research 3 sajsm vol. 29 2017 alternating phase duration of 9:6 seconds. the lbnp device used during this study period was voluntarily supplied by rapid sports medical regeneration, south africa. physiological measurements vital health assessments heart rate (hr), blood pressure (bp) and blood oxygen saturation (spo2) were noted throughout the study, for both the ext and the exc athletes. spo2 (oxyhaemoglobin and deoxy-haemoglobin in the red blood cells) was monitored using a finger pulse oximeter probe (anapulse anp150). blood lactate concentration a small blood sample (0.3µl) was collected by means of a lancet prick of the earlobe to determine the blood lactate concentration (mmol/l) of all athletes (both the ext group and the exc group). analysis was performed using lactate pro™2 test strips (batch# b133b03l) and a portable blood lactate analyser (arkray pro2 lt-1730). lactate was sampled at rest on day one (lac0), immediately after the one hour exercise session (lac1) and directly after the first 30 min lbnp treatment session (lac2). serum creatine kinase enzyme activity levels (ck) ck levels (iu/litre enzyme activity) were assessed from approximately five ml of blood drawn from an antecubital vein by venipuncture. blood samples were obtained at baseline and at 0 hours, 24 hours and 48 hours respectively after treatment and were analysed (creatine phosphokinase assay; beckman unicel® dxc800 synchron) to determine possible increases in ck blood serum levels. perceived recovery questionnaire the questionnaire was based on an ordinal rating scale of one to five, to evaluate the perceived amount of recovery with lbnp therapy (of all athletes: exc and ext). the questions were designed to explore the subjective perceptions of their intensity of muscle soreness and their level of recovery, comparing pre-treatment and post-treatment on the lbnp device (table 1). athletes belonging to the ext group were also questioned on their opinion of the effectiveness of lbnp therapy. data analysis the data analysis consisted of descriptive statistics to table 1. perceived recovery questionnaire question ordinal rating scale 1 5 pre-treatment: how does your body feel after exercise / before treatment? extremely exhausted excellent condition how do your muscles feel? very heavy excellent condition how does your body feel in terms of fatigue? i feel extremely fatigued i feel fully energised post-treatment: how do your muscles feel? very heavy excellent condition how does your body feel in terms of fatigue? i feel extremely fatigued i feel fully energised how well rested and regenerated do you feel? not recovered very well recovered lbnp effectiveness: how do you feel after your treatment session on the lbnp device? my body still feels tired/ fatigued my body feels in great condition do you have the impression that the lbnp device helped? not impressed extremely impressed table 2. baseline physical characteristics of participants (n=22) variables mean ± sd age (years) 20±1 body weight (kg) 79.6±8.2 height (cm) 180.0±0.1 bmi (kg/m2) 24.6±2.5 . fig.1. procedure of physiological measurements and blood samples taken over three consecutive trial days. **intervention starts. hr, heart rate; bp, blood pressure; spo2, blood oxygen saturation; ck, creatine kinase; lac, lactate; qu, questionnaire. original research sajsm vol. 29 2017 4 summarise the quantitative information. repeated measures anova was used to assess the changes in blood lactate concentration and ck activity levels over the 48 hour treatment period between the treatment and control groups. the proportional changes (after vs. before) of the treatment were evaluated and interpreted as follows: values smaller than one indicate a decrease, values larger than one an increase and a value of one would indicate no change took place. the results of the perceived recovery questionnaire were combined into pre-treatment recovery scores and posttreatment recovery scores. non-parametric mann-whitney u tests were performed to determine differences between the treatment and control groups for each of the three periods. the results were regarded as significant if p<0.05, one-tailed. results the baseline physical characteristics of the participants at the start of the study are reported in table 2. figure 2 shows the systolic and diastolic bp for both the ext and the exc athletes. the negative pressure generated by the lbnp device on bp can clearly be seen in the systolic and diastolic fluctuations during the treatment sessions. although there were slight changes in the hr and spo2 measurements before and during each treatment session in the ext and exc groups, there were no significant differences in these physiological measurements; these differences are due to sample variation. figure 3 illustrates the results of the blood lactate concentration (mmol/l) on day one at baseline (lac0), after a one hour (lac1) intense exercise session, and after the first 30 minute (lac2) lbnp therapy session. the average blood lactate concentration (mmol/l) ratio (after vs. before) of the ext group decreased after treatment, in comparison to the exc group who did not receive treatment (0.57±0.23 vs. 0.78±0.22, respectively, f(1;19)=9.420, p=0.006). no other significant differences were obtained. the ck measurements for both groups are shown in figure 4. although there was an increase in ck enzyme activity following the first day’s training, the ck did not decrease significantly after three treatment sessions on the lbnp device (f(1;19)=0.172; p=0.683). figure 5 shows the perceived recovery grading of both exc and ext athletes over a three day period during pre-treatment and post-treatment on the lbnp device (based on the questions in table 1). the three pre-treatment questions were combined to get a pre-treatment recovery score, and the three posttreatment questions were combined to get a post-treatment recovery score. there was a significant difference between the exc and ext groups (post-treatment score minus pre-treatment score) at all three time periods (0h p= 0.011; 24h p<0.001; 48h p=0.001). at post-treatment, after each of the 0 hour, 24 hour and 48 hour sessions, the ext athletes reported a significant increase in their perceived degree of muscle feel, fatigue and recovery compared to the controls. the ext group during each of the treatment periods indicated higher energy and recovery status than the exc group. discussion the decrease in the blood lactate concentration ratio of the treatment group compared to the control group (0.57±0.23 vs. 0.78±0.22 mmol/l, respectively, p<0.001), following a single negative pressure treatment session, indicates that the use of the lbnp device succeeded in normalising lactate measurements more quickly, and may imply faster athlete rehabilitation and recovery. per contra, the severity of muscle injury as indicated by the blood serum ck level of activity was not significantly reduced after three treatment sessions of negative pressure (f(1;19)=0.172; p=0.683). negative vacuum pressure treatment did not affect the ongoing sports performance of the athletes, and no side effects were observed during the period the study was executed. all participants also form part of the same cricket academy and therefore their training schedules are fairly similar. several physiological systems change when endurance training is induced (i.e. metabolic, cardiovascular, muscular, etc.), with the modification of lactate kinetic parameters a significant mediator to quantify the extent of exercise.[12] the mean blood lactate ratio between the control (exc) and treatment (ext) groups, directly after exercise vs. directly fig.2. systolic and diastolic blood pressure (n=22). m, measurement. original research 5 sajsm vol. 29 2017 fig.3. mean blood lactate concentration (mmol/l) on day one at baseline (lac0), after one hour of exercise (lac1), and after 30 minutes therapy (lac2) on the lbnp device (n=22). * ratio significant at <0.01. . fig.4. mean creatine kinase enzyme activity on day one at baseline (ck0), after one hour of exercise and the 1st therapy session (ck1), after the 2nd therapy session (ck2), and after the 3rd therapy session (ck3) (n=22). no significant decrease was found. fig.5. perceived recovery based on an ordinal scale indicating the post-treatment recovery score minus pre-treatment recovery score responses of both exc and ext athletes groups on the lbnp device, for the 0 hour, 24 hour and 48 hour sessions. ordinal scale relates to questions af in table 1.* significant at 5% level; ** significant at 1% level. original research sajsm vol. 29 2017 6 after the 1st treatment session, demonstrated a significantly faster decrease in the treatment group, indicating the efficiency of the lbnp device to stimulate blood flow and as an aid in the removal of lactate. however, the daily academy training and competition programme the athletes followed, although fairly similar, may also have influenced the ck serum results. again, the objective of evaluating negative pressure effect on recovery under acute athlete performance conditions is highlighted in this study. the stimulation of the circulatory system and the lymphatic vessels by the rhythmic alternating pressure of the lbnp device may conceivably mimic massage therapy. sports massage is used by athletes with the belief that it will stimulate lymph flow and reduce muscle tightness in order to accelerate recovery and enhance performance. improvement in muscle tone and a sense of feeling recovered and energised by the increased concentration of endorphins in the brain has also been advocated. although many claimed benefits and numerous personal perceived experiences promote sports massage as the treatment of choice, research evidence on its appropriate use is scarce[10] with contradictory evidence that manual massage has any significant impact on the physiological and psychological factors associated with recovery following exercise.[9,10] recovery may be reliably assessed both at preand posttreatment with one-dimensional tools, such as individual evaluated numeric rating scales. athletes who were treated with the lbnp device during their routine weekly training programme reported an increased subjective impression of treatment compared to that of the control athletes. a perceived improvement in muscle feeling and fatigue was seen, and they experienced increased training motivation and an enhanced feeling of recovery in general. the athletes described the treatments as ‘pleasant’ and rated their treatment sessions on the lbnp device as highly effective, reflecting the impression that the treatment sessions may help them to recover more quickly. at posttreatment, after each of the 0 hour, 24 hour and 48 hour sessions, the ext athletes reported a significant increase in their perceived degree of muscle feel, fatigue and recovery compared to the controls. the ext group, during each of the treatment periods, indicated a higher energy and recovery status than the exc group. the perceived perceptions of recovery that increased after each vacuum therapy session provides some support for the use of the lbnp device as a recovery strategy to improve the recovery state of the athlete. it has to be noted that the project specifically targeted short-term acute recovery and does not reflect on how the use of the lbnp device will be perceived over the long-term. the performance, motivation and subjective wellbeing of the athlete may well be further enhanced with the continuous use of the device. a limitation to this study is the short period the lbnp treatment was implemented, but the core emphasis was to determine acute athlete rehabilitation and recovery based on known measures of muscular recovery within a short period of time after high-intensity exercise. beneficial to the device itself will be a further examination of its effectiveness and significance based on performance enhancement, recovery and rehabilitation of athletes, and the advanced development of various treatment programmes. conclusion based on this study, lbnp therapy implemented as an applied treatment within cricket players’ normal routine training and competition schedule, in an effort to assist in the recovery of players over a short period of time, seems to have a systemic effect in lowering serum lactate levels, but not ck levels. the enhanced long-term recovery of athletes using this device to replenish faster and recuperate more efficiently as advocated, are still unconfirmed. acknowledgements: the authors are grateful to gustav obermeyer of rapid sports medical regeneration (rsmr), south africa who voluntarily supplied the vacumed (lbnp device) for the research performed at the university of pretoria, south africa. conflicts of interest: there are no conflicts of interest related to this study. source of funding: the authors declare that they have not received any funding for this study. statement: the protocol was approved by the ethics committee of the university of pretoria, south africa (approval number 352-2013). experiments comply with the current laws of south africa in which they were performed. references 1. baisch f, beck l, blomqvist g, et al. cardiovascular response to lower body negative pressure stimulation before, during, and after space flight. eur j clin invest 2000;30(12):1055-1065. [http://dx.doi.org/10.1046/j.1365-2362.2000.00750.x] 2. cooper vl, hainsworth r. carotid baroreceptor reflexes in humans during orthostatic stress. exp physiol 2001;86(5):677681. [http://dx.doi.org/10.1113/eph8602213] 3. hisdal j, toska k, flatebø t, et al. onset of mild lower body negative pressure induces transient change in mean arterial pressure in humans. eur j appl physiol 2002;87(3):251-256. [http://dx.doi.org/10.1007/s00421-002-0630-4] 4. stannard jp, singanamala n, volgas da. fix and flap in the era of vacuum suction devices: what do we know in terms of evidence based medicine? injury 2010;41(8):780-786. [http://dx.doi.org/10.1016/j.injury.2009.08.011] 5. hachiya t, blaber ap, saito m. changes in superficial blood distribution in thigh muscle during lbnp assessed by nirs. aviat space environ med 2004;75(2):118-122. [http://www.ingentaconnect.com/content/asma/asem/2004/00 000075/00000002/art00004] 6. krug e, berg l, lee c, et al. evidence-based recommendations for the use of negative pressure wound therapy in traumatic wounds and reconstructive surgery: steps towards an international consensus. injury 2011;42 suppl.1:s1-s12. [http://dx.doi.org/10.1016/s0020-1383(11)00041-6] 7. schneider sm, watenpaugh de, lee sm, et al. lower-body http://dx.doi.org/10.1046/j.1365-2362.2000.00750.x http://dx.doi.org/10.1113/eph8602213 http://dx.doi.org/10.1007/s00421-002-0630-4 http://dx.doi.org/10.1016/j.injury.2009.08.011 http://www.ingentaconnect.com/content/asma/asem/2004/00000075/00000002/art00004 http://www.ingentaconnect.com/content/asma/asem/2004/00000075/00000002/art00004 http://dx.doi.org/10.1016/s0020-1383(11)00041-6 original research 7 sajsm vol. 29 2017 negative-pressure exercise and bed-rest-mediated orthostatic intolerance. med sci sports exerc 2002;34(9):1446-1453. [http://dx.doi.org/10.1097/00005768-200209000-00008] 8. torres r, ribeiro f, alberto duarte j, et al. evidence of the physiotherapeutic interventions used currently after exercise-induced muscle damage: systematic review and meta-analysis. phys ther sport 2012;13(2):101-114. [http://dx.doi.org/10.1016/j.ptsp.2011.07.005] 9. hemmings b, smith m, graydon j, et al. effects of massage on physiological restoration, perceived recovery, and repeated sports performance. br j sports med 2000;34(2):109114. [http://dx.doi.org/10.1136/bjsm.34.2.109] 10. brummitt j. the role of massage in sports performance and rehabilitation: current evidence and future direction. n am j sports phys ther 2008;3(1):7-21. [http://www.ncbi.nlm.nih.gov/pmc/journals/1328/] [pmcid: pmc2953308] 11. brooks ga. the lactate shuttle during exercise and recovery. med sci sports exerc 1986;18(3):360-368. [http://dx.doi.org/10.1249/00005768-198606000-00019] [pmid:3523107] 12. gharbi a, chamari k, kallel a, et al. lactate kinetics after intermittent and continuous exercise training. j sports sci med 2008;7(2):279-285. [http://www.jssm.org/researchjssm-07279.xml.xml] [pmcid: pmc3761459] 13. menzies p, menzies c, mcintyre l, et al. blood lactate clearance during active recovery after an intense running bout depends on the intensity of the active recovery. j sports sci 2010;28(9):975-982. [http://dx.doi.org/10.1080/02640414.2010.481721] 14. baird mf, graham sm, baker js, et al. creatine-kinaseand exercise-related muscle damage implications for muscle performance and recovery. j nutr metab 2012;2012: 960363. [http://dx.doi.org/10.1155/2012/960363] 15. gasiorowska a, mikulski t, smorawiński j, et al. cardiovascular and neurohormonal responses to lower body negative pressure (lbnp): effect of training and 3 day bed rest. j physiol pharmacol 2006;57 suppl.10:85-100. [http://jpp.krakow.pl/journal/archive/11_06_s10/articles/07_art icle.html] http://dx.doi.org/10.1097/00005768-200209000-00008 http://dx.doi.org/10.1016/j.ptsp.2011.07.005 http://dx.doi.org/10.1136/bjsm.34.2.109 http://dx.doi.org/10.1249/00005768-198606000-00019 http://dx.doi.org/10.1080/02640414.2010.481721 http://dx.doi.org/10.1155/2012/960363 http://jpp.krakow.pl/journal/archive/11_06_s10/articles/07_article.html http://jpp.krakow.pl/journal/archive/11_06_s10/articles/07_article.html editorial 34 sajsm vol. 26 no. 2 2014 first principles: reasons to always go back i did a double take when i received an email from a friend with the subject line ‘how to run “naked” – and love it’. my immediate thought was that he had lost his marbles, but i clicked on the link not quite sure what to expect. my concern was ill-founded because the link directed me to a blog about the joys of running free of smartphones, heartrate monitors, headphones, gps devices, etc.; ‘naked’ was referring to the deprivation of technology.[1] the article implied that technology, which has become such an important part of running, detracted from the natural joys of running – the very thing that was attractive in the beginning. this prompted a tongue-in-cheek response from another friend, david, a once-elite race walker, who was on the mailing list: ‘thanks for the info on the devices. looks very interesting. my watch broke about 15 years ago; never used the other devices. so, i guess i’ve been running “naked” for a while. i still use my original hr, bp, o2/co2 sensors located in various locations in my body. forgot where? they provide continuous feedback to some device that then adjusts hr, o2 extraction and co2 loading, respiratory volume and rate. this according to some algorithm that apparently accounts for energy status/demand. works well; i don’t even have to think about it.’ while this was said in jest, it was insightful and summarises the concept of the central governor.[2] this theory explains the anticipatory regulation of pacing during exercise, and occurs independently of any external hardware or software. david’s comment and the blog got me thinking about how easy it is to drift away from first principles. we are quick to embrace technology, particularly if the new technology measures something that we can use in research, in service to clients or patients, or if we think it is going to improve performance. however, if first principles are neglected, the accuracy of the measurement may be questionable. first principles imply that the following questions can be answered: • how reliable is the measurement? • is the measurement valid? • does the measurement respond to changes with sufficient sensitivity? • is the measurement error less than the smallest worthwhile change? these are simple first-principle questions, the answers of which should be known before the measurements are applied. alas, this often does not happen, and tests or devices that measure things are often used and applied before they have undergone this source of evaluation. there are many examples: consider the portable lactate analysers that became fashionable about 15 years ago.[3] while they could measure lactate concentrations in a tiny blood sample obtained from a finger prick, the measurement error exceeded the smallest meaningful change in lactate concentration during exercise. an understanding of first principles would have exposed the pitfalls in measuring lactate as a marker of training status. a situation where the measurement error exceeds the smallest worthwhile change makes the measurement uninterpretable. despite this, many trainers and coaches insisted on measuring lactate during exercise and still do so today; the only conclusion is that they do it to look smart, because the practical outcomes of such a measurement are questionable. perhaps the most outrageous example of not understanding first principles was a nutritional supplement that was marketed as an adenosine triphosphate (atp) replacement. the manufacturer of the supplement glossed over the fact that ingested atp gets broken down as it is digested and does not reach the muscles and increase the concentration of atp as claimed. a consumer without the firstprinciple knowledge of digestion and metabolism would miss the faulty logic and could easily succumb to the pitfalls of such claims. therefore it is important for practitioners to revisit first principles gove r n i ng t he i r d is c ipl i ne. it is important for students to be taught using first principles as the basis of their learning. the public should also be educated about the mechanism of action of treatments and be encouraged to adopt a questioning, skeptical outlook. finally, it may be appropriate to have a ‘running naked’ day just to remind us of the importance of first principles. mike lambert editor-in-chief references 1. gay j. how to run ‘naked’ – and love it. http://online.wsj.com/articles/how-to-runnakedand-love-it-1401323053 (accessed 8 june 2014). 2. noakes td. time to move beyond a brainless exercise physiology: the evidence for complex regulation of human exercise performance. appl physiol nutr metab 2011;36(1):23-35. [http://dx.doi.org/10.1139/h10-082] 3. swart j, jennings c. use of blood lactate concentration as a marker of training status. south african journal of sports medicine. 2004;16(3):3-7. http://online.wsj.com/articles/how-to-run-nakedand-love-it-1401323053 http://online.wsj.com/articles/how-to-run-nakedand-love-it-1401323053 http://online.wsj.com/articles/how-to-run-nakedand-love-it-1401323053 http://dx.doi.org/10.1139/h10-082] sajsm 595 (commentarty).indd commentary 1 sajsm vol. 29 2017 neuroimaging in contact sports: determining brain fitness before and after a bout n k sethi, md department of neurology, new york presbyterian hospital, weill cornell medical center, new york, usa corresponding author: n k sethi (sethinitinmd@hotmail.com) the risks for both acute and chronic traumatic brain injury are high in contact sports such as professional boxing and mma. brain imaging, either computed tomography (ct) or magnetic resonance imaging (mri), is currently included in the process of registering for a license to fight in combat sports. the imaging requirements for licensure, though vary. some state commissions in the united states require an mri brain scan every three years, others once, at the time of licensure, and some do not require any imaging prior to licensure. brain imaging, particularly a ct scan of the head is currently the imaging modality of choice to rule out acute traumatic brain injury after a bout. there are no guidelines regarding the imaging for chronic traumatic brain injury and chronic traumatic encephalopathy. neuroimaging prior to licensure neuroimaging prior to licensure helps in the guiding of the clinical judgement of supervisory personnel (ringside physicians) regarding whether the combatant should participate in future bouts. it also helps to identify and/or exclude coincidental or clinically suspected brain lesions which may pose a risk for rupture, bleeding or other catastrophic and other injuries to the brain injury should a combatant participate in future bouts. these structural lesions include but are not limited to cerebral aneurysms, arteriovenous malformations, large cavernous malformations, mixed malformations, vein of galen malformations, large venous malformations, large arachnoid cysts, posterior fossa arachnoid cysts, pituitary macroadenomas and other space-occupying lesions, such as large tumours. it is important to emphasise that the above represents a fairly heterogeneous group of cerebral and cerebrovascular lesions which demonstrate different natural histories and a propensity to bleed. a less urgent but by no means less important role of neuroimaging prior to licensure is to identify any evidence of prior structural injury possibly or probably associated specifically with brain trauma, which may make a combatant more likely to express late-life neuropsychiatric sequelae of brain injury such as chronic traumatic encephalopathy (cte), dementia pugilistica, chronic post-concussion syndrome, chronic neurocognitive impairment, posttraumatic dementia, posttraumatic cognitive impairment, posttraumatic parkinsonism and persistent posttraumatic headache. [1, 2] this information allows the physician and combatant to make decisions about the combatant’s future health, particularly when some of the findings may be ambiguous either in their appearance or in the implication for and risk of future neurologic sequelae. either a ct or mri is currently included in the process of registering for a license to fight in combat sports in most states in the united states and around the world. [3] the imaging specifics and frequency varies widely throughout u.s. states, with some state commissions requiring a mri brain scan every three years and others only once, i.e. at the time of licensure. some state commissions do not require any imaging prior to licensure, while new york details the required imaging sequences (table 1). some commissions require that all background: professional boxing and mixed martial arts (mma) are popular contact sports with high risk for both acute and chronic traumatic brain injury (tbi). although rare, combatants have died in the ring/cage or soon after the completion of the bout. the cause of death in these cases is usually acute subdural hematoma, acute epidural hematoma, subarachnoid haemorrhage, intracranial haemorrhage, or second-impact syndrome (sis). neuroimaging or brain imaging is currently included in the process of registering for a license to fight in a combat sport in most states in the united states and around the world. however, the required imaging specifics and frequency vary. discussion: neuroimaging serves two distinct roles in the individualised care of a combatant, representing a step towards personalised medicine and individual risk stratification. neuroimaging prior to licensure helps to identify and/or exclude coincidental or clinically suspected brain lesions which may pose a risk for rupture, bleeding or other catastrophic and important brain injury. neuroimaging in the immediate aftermath of a bout primarily serves to rule out acute traumatic brain injury. neuroimaging may also be carried out to assess for evidence of structural brain injury which may make a combatant more likely to express late-life neuropsychiatric sequelae of brain injury, such as chronic traumatic encephalopathy. as such, neuroimaging plays a prognostic role and aids in the determination of whether the combatant should be allowed to continue to participate in future bouts or not. conclusion: currently there are no established neuroimaging guidelines for contact sports. standardising neuroimaging guidelines both for licensure as well as neuroimaging modality, and protocols to assess for both acute and chronic traumatic brain injury. this will assist in protecting the combatant’s health and safety, both in the ring/cage, and after their professional careers have ended. some suggested guidelines are provided based on currently available medical literature. it is recommended that these guidelines be debated vigorously by the scientific community and that evidence-based guidelines be developed by the medical community in conjunction with professional boxing and mma governing bodies. keywords: boxing, mma, traumatic brain injury, chronic traumatic encephalopathy s afr j sports med 2017;29:1-4.doi: 10.17159/2078-516x/2017/v29i0a2390 http://dx.doi.org/10.17159/2078-516x/2017/v29i0a2390 commentary sajsm vol. 29 2017 2 combatants undergo a magnetic resonance angiogram (mra) table 1. imaging requirements for licensure for professional boxing and mma of various commissions in the united states and around the world us state imaging requirements alabama (al) radiological exams: none at this time. neurological exam: any applicant that is more than 37 years of age and/or has competed in more than 200 professional rounds must submit a detailed neurological examination conducted by a state licensed neurologist. arizona (az) radiological exams: none at this time. neurological exam: not at this time. arkansas (ar) radiological exams: none at this time. neurological exam: not at this time. california (ca) radiological exams: an mri of the brain without contrast and the gre technique results must also be included. the mri scan is to be performed on a 1.5 tesla mr machine with capabilities including fast spin echo and flair imaging. image sequences should include axial t1, t2, and flair images; coronal images should be performed as a t2 coronal; and a single sagittal t1 sequence. the images should be placed on a cd as soon as possible and forwarded to the commission at: 2005 evergreen st., suite 2010, sacramento, ca, 95815. if a cd is not available, please forward the actual film within ten (10) days to avoid suspension of the license. the mri is valid for five years. neurological exam: a neurological exam is required and is valid for 15 months colorado (co) radiological exams: none at this time. neurological exam: not at this time. connecticut (ct) radiological exams: it is the fighter’s choice of an mri, ct scan, or neurological exam. all tests/exams are good for three to four years from the date of the fight. neurological exam: it is the fighter’s choice of an mri, ct scan, or neurological exam. all tests/exams are good for three to four years from the date of the fight. florida (fl) radiological exams: none at this time. neurological exam: not at this time delaware (de) radiological exams: fighters who have not fought within the last 16 months or have had five or more knockouts must submit a ct scan administered by a licensed md or do. neurological exam: fighters who have not fought within the last 16 months or have had five or more knockouts must submit a ct scan administered by a licensed md or do. georgia (ga) radiological exams: none at this time neurological exams: not at this time. changes will be made in the near future. nevada (nv) radiological exams: must submit an mri or mra of the brain without contrast. this exam is a one-time requirement, unless otherwise ordered. neurological exam: not at this time. new jersey (nj) radiological exams: ct or mri of the brain without contrast dated within three years of the event is required. neurological exam: not at this time. maryland (md) radiological exams: none at this time. neurological exam: boxers must take a neurological exam and it must be completed prior to the boxer participating in his/her first bout (paid for and chosen by the commission). oklahoma (ok) radiological exams: none at this time. neurological exam: not at this time. illinois (il) radiological exams: none at this time. neurological exam: not at this time. hawaii (hi) radiological exams: none at this time. neurological exam: not at this time. additional requirements: any fighter that has fought 120 rounds or has not competed within the last 36 months may be subject to additional tests/exams as determined by a licensed physician. all these additional tests/exams will be valid for one year. new york (ny) radiological exams: mri brain 1.5 tesla (minimum) or 3 tesla magnet. required mri sequences: t1, t2, flair, diffusion weighted image (dwi), gradient echo (gre) or susceptibility weight imaging (swi) every three years or as required by the commission neurological exam: not at this time. british boxing board of control mri/mra brain scan report commentary 3 sajsm vol. 29 2017 combatants undergo a magnetic resonance angiogram (mra) of the brain at the start of their professional career (time of licensure) primarily to exclude any incidental vascular malformations of the brain which have a high propensity to bleed (table 1). the mri is generally considered to be superior to a ct for detecting the stigmata of chronic tbi. although the ct is better at detecting bony pathology, some studies have shown that it may have missed between 10–20% of abnormalities seen on an mri. [3, 4] the ability of the mri to detect hematomas improves over time as the composition of the blood changes. the overwhelming majority of patients with mild brain injury shows no abnormality on an mri, but coincidental structural brain abnormalities are found in about 2-3% of all studies, including meningiomas, coincidental and non-pathologic anomalies, and small often static cerebral aneurysms. cerebral vasculature anomalies are particularly frequent in the circle of willis. with reference to contact sports, relevant abnormalities include hemorrhagic cortical contusions, petechiae, or foci of altered signal that represent white matter shear injury. [5] when petechiae resolve, they leave a permanent hemosiderin deposition on the mri. an mri is superior to a ct in the detection of axonal injury, small areas of contusion, and subtle neuronal damage. stigmata of old tbi on an mri also include areas of encephalomalacia and gliosis, particularly in areas prone to coup-contrecoup forces, such as the frontal lobe (anterior as well as inferior margin along the cribiform plate), anterior temporal lobe, and the occipital pole. the mri is also superior to a ct at imaging the brainstem, basal ganglia, and thalami. fluid-attenuated inversion recovery (flair) mri, a sequence that suppresses the high signal from cerebrospinal fluid (csf) by using a long inversion time (t1), has been found to be more sensitive in detecting traumatic lesions and hematomas. white matter abnormalities may be seen on an mri in patients with mild tbi. however, it should be remembered that white matter changes are also found in a large percentage of healthy middle-aged individuals, middle-aged persons with chronic vascular risk factors including hypertension, as well as younger patients with migraines..[2] newer mri technology and acquisition sequences have improved the sensitivity of the mri for detecting the stigmata of tbi, but not all sequences are routinely adopted or performed in clinical contexts and some are presently strictly related to research. [5, 6] among these in particular is diffusion tensor imaging (dti); traumatic axonal injury which is characterised by a reduction in fractional anisotrophy (fa) on dti. [7] magnetisation transfer imaging (mti), which applies radio frequency power only to the protons in the macromolecules of tissues rather than the protons in water, can add sensitivity to an mri. magnetic source imaging (msi), using a combination of mri and magnetoencephalography (meg), was found to be superior to using only an mri in the detection of tbi. proton magnetic resonance spectroscopic imaging (1h-mrsi) has been found to be a sensitive tool in detecting axonal injury in the corpus callosum of tbi patients. functional mri can demonstrate changes in regional brain activation in patients with mild tbi. susceptibility-weighted imaging (swi) and arterial spin labelling (asl) are newer mri methods for better detection of tbi. [6] there are presently no good biomarkers (biofluids or imaging) for chronic tbi and its reported link with chronic traumatic encephalopathy (cte). [8] multimodal imaging techniques may help to enhance the yield of detection and characterisation of stigmata of prior tbi. along with neuropsychological testing, these methods may help in the prediction of injuries to fighters who partake in contact sports by providing information of neural networks that subserve cognition and executive function. [9] it is hoped that with advances in neuroimaging and the development of imaging and biofluid biomarkers for tbi and cte will lead to the development of rational and evidence-based medicine approaches to the management and risk stratification of fighters who demonstrate evidence of prior tbi on their mri scans. recommended good practice guidelines regarding neuroimaging requirements prior to licensure: 1. to ensure the health and safety of all combat sports participants, it is recommended that neuroimaging requirements prior to licensure be standardised across different commissions and sports governing bodies in all countries. standardisation of neuroimaging requirements shall allow the physician and combatant to take measured decisions about the combatant’s future health and brain fitness to begin fighting or continue to fight. 2. it is recommended that the various commissions and sports governing bodies coordinate to assist with the setting up of an online central neuroimaging database so that neuroimaging data can be shared in the different countries where the fighter may fight. 3. a brain mri is the recommended imaging modality of choice to assess brain fitness to fight as well as to predict possible long-term effects of multiple hits to the head and assess stigmata of chronic tbi. 4. when a brain mri is not feasible, either due to its nonavailability or if the cost is prohibitive, a ct brain scan may suffice with the knowledge of the limitations of ct scan technology as documented above. 5. the decision to medically clear a fighter to fight when the brain mri suggests evidence of prior/chronic tbi should be made on a case-by-case basis after careful consideration and review of the fighter’s medical history, age, fight record, neurological examination and neurocognitive performance. ringside physicians may request additional neuroimaging (as detailed below) and a formal neuropsychological evaluation of a fighter. 6. risk stratification is the process of identifying the individual risk of a combatant suffering from a particular condition after careful review of history, laboratory and clinical tests. some combatants may warrant disqualification and denial of license to fight and others may be medically cleared to fight after careful review of all relevant history and imaging findings as mentioned above. neuroimaging after a bout the prime need for neuroimaging after a bout is to ascertain acute tbi. a ct scan of the head without contrast is the recommended imaging modality due to its relatively high sensitivity and specificity for identifying the presence of blood in the acute setting, its widespread availability and short acquisition time. commentary sajsm vol. 29 2017 4 recommended good practice guidelines regarding neuroimaging requirements after a bout: 1. based on the assessment by the ringside physician(s) after the post-fight physical examination, a combatant who is suspected of having sustained a tbi should be transported immediately by ambulance to the designated level i trauma centre for an emergency assessment of possible tbi/concussion, an urgent ct scan of the head, and further care as deemed necessary by the trauma centre physicians. concern for tbi is raised if the combatant manifests or reports symptoms of headache, blurred vision, double vision, nausea, vomiting, balance or gait issues after a bout. [10,11] 2. any combatant with a glasgow coma scale/score (gcs) of less than 13 on initial assessment, suspected open or depressed skull fracture, suspected basal skull fracture, post-traumatic seizure, focal neurological deficit and/or greater than one episode of vomiting since the suspected head injury should be urgently transported to the designated level i trauma centre via an on-site ambulance for a ct scan of the head (as per national institutes of health and care excellence (nice) guidelines for determining the need for an acute ct scan of the head in adults following a traumatic head injury). [12] conclusion it is recommended that the best practice guidelines as mentioned above be debated vigorously by ringside physicians and the larger scientific community. the evidence-based guidelines on neuroimaging requirements prior to licensure, in the immediate post-bout setting, and the assessment for the stigmata of chronic tbi and cte be investigated by the medical community in conjunction with professional boxing and mma governing bodies. the establishment of these guidelines will go a long way in ensuring the health and safety of professional combatants. author contributions: nks conceived, drafted and revised the manuscript. study funding: no targeted funding reported. disclosure: nks serves as associate editor, the eastern journal of medicine and as chief medical officer of the new york state athletic commission (nysac). the views expressed are his and do not represent the views of the nysac. references 1. ling h, hardy j, zetterberg h. neurological consequences of traumatic brain injuries in sports. mol cell neurosci 2015; 66(pt b):114122. [doi: 10.1016/j.mcn.2015.03.012] 2. seifert t, bernick c, jordan b, et al. determining brain fitness to fight: has the time come? phys sportsmed. 2015; 43:395-402. [doi: 10.1080/00913847.2015.1081551] 3. jordan bd, jahre c, hauser wa, et al. ct of 338 active professional boxers. radiology 1992; 185:509-512. [doi: 10.1148/radiology.185.2.1410364] 4. lee b, newberg a. neuroimaging in traumatic brain imaging. neurorx 2005; 2: 372–383. [doi: 10.1602/neurorx.2.2.372] 5. koerte ik, hufschmidt j, muehlmann m, et al. advanced neuroimaging of mild traumatic brain injury. in: laskowitz d, grant g, eds. translational research in traumatic brain injury. boca raton (fl): crc press/taylor and francis group; 2016. chapter 13. 6. van boven rw, harrington gs, hackney db,et al. advances in neuroimaging of traumatic brain injury and posttraumatic stress disorder. j rehabil res dev 2009; 46:717-757. [pmcid: pmc3233771] 7. li l, sun g, liu k,et al. white matter changes in posttraumatic stress disorder following mild traumatic brain injury: a prospective longitudinal diffusion tensor imaging study. chin med j (engl) 2016; 129:1091-1099. [doi: 10.4103/0366-6999.180518] 8. papa l, ramia mm, edwards d, et al. systematic review of clinical studies examining biomarkers of brain injury in athletes after sports-related concussion. j neurotrauma 2015; 32:661-673. [doi: 10.1089/neu.2014.3655] 9. multani n, goswami r, khodadadi m, et al. the association between white-matter tract abnormalities, and neuropsychiatric and cognitive symptoms in retired professional football players with multiple concussions. j neurol 2016; 263:1332-1341. [doi: 10.1007/s00415-016-81410] 10. national clinical guideline centre (uk). head injury: triage, assessment, investigation and early management of head injury in children, young people and adults. london: national institute for health and care excellence (uk); 2014 jan. [pmid: 25340248] 11. davis t, ings a, national institute of health and care excellence. head injury: triage, assessment, investigation and early management of head injury in children, young people and adults (nice guideline cg 176). arch dis child educ pract ed 2015; 100:97-100. [doi: 10.1136/archdischild-2014-306797] 12. hodgkinson s, pollit v, sharpin c, et al. early management of head injury: summary of updated nice guidance. bmj 2014; 348:g104. [doi: 10.1136/bmj.g104] https://www.ncbi.nlm.nih.gov/pubmed/?term=ling%20h%5bauthor%5d&cauthor=true&cauthor_uid=25770439 https://www.ncbi.nlm.nih.gov/pubmed/?term=hardy%20j%5bauthor%5d&cauthor=true&cauthor_uid=25770439 https://www.ncbi.nlm.nih.gov/pubmed/?term=zetterberg%20h%5bauthor%5d&cauthor=true&cauthor_uid=25770439 https://www.ncbi.nlm.nih.gov/pubmed/25770439 https://www.ncbi.nlm.nih.gov/pubmed/?term=seifert%20t%5bauthor%5d&cauthor=true&cauthor_uid=26295482 https://www.ncbi.nlm.nih.gov/pubmed/?term=bernick%20c%5bauthor%5d&cauthor=true&cauthor_uid=26295482 https://www.ncbi.nlm.nih.gov/pubmed/?term=jordan%20b%5bauthor%5d&cauthor=true&cauthor_uid=26295482 https://www.ncbi.nlm.nih.gov/pubmed/?term=26295482 https://www.ncbi.nlm.nih.gov/pubmed/?term=jordan%20bd%5bauthor%5d&cauthor=true&cauthor_uid=1410364 https://www.ncbi.nlm.nih.gov/pubmed/?term=jahre%20c%5bauthor%5d&cauthor=true&cauthor_uid=1410364 https://www.ncbi.nlm.nih.gov/pubmed/?term=hauser%20wa%5bauthor%5d&cauthor=true&cauthor_uid=1410364 https://www.ncbi.nlm.nih.gov/pubmed/?term=1410364 https://www.ncbi.nlm.nih.gov/pubmed/?term=lee%20b%5bauthor%5d&cauthor=true&cauthor_uid=15897957 https://www.ncbi.nlm.nih.gov/pmc/articles/pmc1064998/ https://www.ncbi.nlm.nih.gov/pubmed?term=koerte%20ik%5bauthor%5d&cauthor=true&cauthor_uid=26583173 https://www.ncbi.nlm.nih.gov/pubmed?term=hufschmidt%20j%5bauthor%5d&cauthor=true&cauthor_uid=26583173 https://www.ncbi.nlm.nih.gov/pubmed?term=muehlmann%20m%5bauthor%5d&cauthor=true&cauthor_uid=26583173 https://www.ncbi.nlm.nih.gov/pubmed?term=laskowitz%20d%5beditor%5d https://www.ncbi.nlm.nih.gov/pubmed?term=laskowitz%20d%5beditor%5d https://www.ncbi.nlm.nih.gov/pubmed?term=grant%20g%5beditor%5d https://www.ncbi.nlm.nih.gov/pubmed/20104401 https://www.ncbi.nlm.nih.gov/pubmed/20104401 https://www.ncbi.nlm.nih.gov/pubmed/27098796 https://www.ncbi.nlm.nih.gov/pubmed/27098796 https://www.ncbi.nlm.nih.gov/pubmed/27098796 https://www.ncbi.nlm.nih.gov/pubmed/25254425 https://www.ncbi.nlm.nih.gov/pubmed/25254425 https://www.ncbi.nlm.nih.gov/pubmed/25254425 https://www.ncbi.nlm.nih.gov/pubmed/27142715 https://www.ncbi.nlm.nih.gov/pubmed/27142715 https://www.ncbi.nlm.nih.gov/pubmed/27142715 https://www.ncbi.nlm.nih.gov/pubmed/27142715 https://www.ncbi.nlm.nih.gov/pubmed/25340248 https://www.ncbi.nlm.nih.gov/pubmed/25340248 https://www.ncbi.nlm.nih.gov/pubmed/25340248 https://www.ncbi.nlm.nih.gov/pubmed/25335757 https://www.ncbi.nlm.nih.gov/pubmed/25335757 https://www.ncbi.nlm.nih.gov/pubmed/25335757 https://www.ncbi.nlm.nih.gov/pubmed/24452622 https://www.ncbi.nlm.nih.gov/pubmed/24452622 20 sajsm vol 19 no. 1 2007 introduction in professional sport, much research has focused on the possible advantages 1,4,10-12 and disadvantages 3,17,19,20 associated with being the home or visiting team. when tournaments have games played according to a balanced home and away schedule, there is compelling evidence that a home advantage phenomenon exists. 6,12 local crowds, familiarity with local conditions, travel and rules appear to contribute to this phenomenon. 12 the rugby union super 12 competition was an annual sporting event which existed from 1996 to 2005 and involved teams from australia (n = 3), new zealand (n = 5) and south africa (n = 4). the teams competed according to an unbalanced home and away schedule. 7,10 the south african teams travelled away from home for a continuous 4 5 weeks, whereas the australian and new zealand teams were away from home for 2 3 weeks. the cumulative change in time zones for the south african teams during the competition was about 37.3 ± 2.5 time zones compared with 19.7 ± 1.2 and 21.7 ± 1.7 cumulative time zone changes for the australian and new zealand teams respectively. although it has previously been shown that a home ground advantage in this tournament does indeed exist, 7,10 there is evidence to suggest that the advantages of playing at home may be negated by the disadvantages associated with fatigue resulting from travel and changing time zones. 15,16,18 in the 10 years of the competition a south african team has never won the tournament. a common explanation among fans and the local media for the relatively poor performances of the south african teams is that they spend more consecutive time away from home than their australian and new zealand counterparts and thus accumulate more travel fatigue. at present there are no data to support this perception. this theory can be tested by determining whether the south african teams perform better at home before they travel compared with their home matches after travelling for their 4 5-week trip to australia and new zealand. indeed, if travel fatigue did have a detrimental effect on performance then original research article travel fatigue and home ground advantage in south african super 12 rugby teams m du preez (bsc (med) (hons) exercise science) m i lambert (phd) department of human biology, medical research council/university of cape town research unit for exercise science and sports medicine abstract objectives. studies have shown the existence of a significant home ground advantage in a range of sports. the aim of this study was to determine whether home performances of the south african teams during the 1996 2005 seasons were different before touring to australia and new zealand, compared with the home matches played after the 4 5-week tour. the question was relevant because this competition places unusual demands on the players. for example, the duration of the tournament is 12 weeks, during which time the south african teams travel across 37.3 ± 2.5 time zones as they play 11 matches. therefore, any home ground advantage may be negated by travel fatigue. outcome measures. the mean points difference was calculated for home fixtures for four south african teams both prior to and following touring during the competitions from 1996 to 2005. play-off matches were excluded from analysis. performance was defined as a positive points difference (points difference = points ‘for’ minus points ‘against’). results. the first finding of the study was that a home ground advantage did indeed exist for all the teams during the tournament (points difference of 6.6 ± 17.4 (n = 664 matches) home vs. -6.8 ± 17.3 points away (n = 656 matches) (p < 0.05). there was no difference between the mean ‘home’ points difference for all the south african rugby teams either before (1.9 points, n = 96 matches) or after (2.3 points, n = 107 matches) touring overseas in the super 12 competition. correspondence: m lambert mrc/uct exercise science and sports medicine po box 115 newlands 7725 fax: 021-686 7530 tel: 021-650 4569 e-mail: mike.lambert@uct.ac.za conclusion. the findings suggest that in this tournament unsuccessful campaigns on the part of south african teams could not be attributed to travel fatigue. pg20-22.indd 20 4/4/07 10:55:42 am the south african teams would consistently perform worse at home after travelling to australia and new zealand compared with their performances at home before travelling. therefore the aim of this study was to determine whether home performances of the south african teams during the 1996 2005 seasons were different before touring to australia and new zealand, compared with the home matches played after the 4 5-week tour. methods scores from 1996 through to 2005, excluding the semi-final and final stages of the super 12 rugby union competition, were obtained for all the teams from australia (n = 3), new zealand (n = 5) and south africa (n = 4) (n = 1 320 matches). the points difference was determined for all the south african teams (sharks, stormers, cats and bulls) when they played at their home stadiums. a positive points difference indicates that the home team won the match. the matches were categorised into matches played at home before or after travelling on a 4 5-week trip to australia and new zealand. an analysis of variance (anova) with repeated measures was used to determine differences between teams and home performances either before or after touring (statistica version 6.0, tulsa, usa). statistical significance was accepted as p < 0.05. data are expressed as means ± standard deviation (sd) or as 95% confidence intervals (cis). results the mean home points difference for all the super 12 teams (n = 12) in the competition from 1996 to 2005 was positive and significantly greater than the negative mean away points difference (6.6 ± 17.4 points vs. -6.8 ± 17.3 points respectively, p < 0.05). the 95% cis for these values are 5.3 to 7.9 points (home) and -8.1 to -5.4 points (away). these data were calculated from 664 home matches and 656 away matches. the significant difference also occurred when the south african teams were analysed as a subgroup; 0.2 to 4.4 points difference (95% ci) home (n = 221) and -14.4 to -9.6 points difference (95% ci) away (n = 219). there was no difference between the mean ‘home’ points difference for all the south african rugby teams either before (mean = 1.9, 95% ci: -1.4 to 5.2 points, n = 96 matches) or after (mean = 2.3, 95% ci: -0.8 to 5.4 points, n = 107 matches) touring in the super 12 competition. the reason that the sample size is reduced when the data were analysed this way is that the teams sometimes did not play home matches either before or after travelling. this depended on the schedule for the season. for example, in 1996 the cats did not play any home matches before touring and in 1999 the cats did not play any home matches after touring. similar examples can also be found for the other teams. the data are subdivided into the individual teams and shown in fig. 1. there was no statistical significance between the home points difference before touring and the home points difference after touring for the sharks (95% ci of home matches before travelling vs. 95% ci of home matches after travelling: -2.6 to 12.5 vs. -2.5 to 8.8 points), stormers (-4.9 to 10.7 vs. -9.9 to 4.1 points), cats (-3.1 to 7.4 vs. -3.6 to 11.3 points) and bulls (-9.7 to 5.1 vs. -1.4 to 10.3). however when the data were analysed using magnitude based inferences 2 it may be concluded that the stormers had a ‘possibly trivial’ lower points at home after travelling whereas the bulls had a ‘possibly trivial’ lower points difference before travelling (fig. 1). discussion the first finding of the study showed that in the super 12 competition (1996 2005), involving 1 320 matches, the mean home points difference was positive and significantly greater than the mean away points difference. this home ground advantage also occurred for the four south african teams when they were analysed on their own. this confirms that home ground advantage exists in this competition, supporting findings from du preez and walpole 7 who found a points difference of 7.4 ± 6.9 points (home) vs. -7.4 ± 7.9 points (away) in the 2004 competition. therefore it may be concluded that teams generally outscore their opponents when playing at home in this competition. this may have implications for success in the tournament as the competition lacks balance (i.e. a team either plays 5 or 6 home matches) and a team might play a weaker team at home one year and away the next. 10 the second finding of this study was that the south african teams did not perform significantly better at home before travelling compared with home performances after returning from their 4 5-week trip to australia and new zealand. this suggests that reports of south african teams being at a disadvantage because of the travelling were not supported by the data. had this been the case then the teams would have generally performed at home better before, compared with 11 -15 -10 -5 0 5 10 15 sharks stormers cats bulls p o i n t s d i f f e r e n c e fig. 1. the points difference for the home matches of the sharks, stormers, cats, and bulls before departing for () and after touring () australia and new zealand. values are expressed as mean ± 95% ci. the number of matches analysed are: sharks n = 24 before, n = 27 after; stormers n = 19 before, n = 25 after; cats n = 29 before n = 25 after; bulls n = 24 before, n = 30 after. fig. 1. the points difference for the home matches of the sharks, stormers, cats, and bulls before departing for (•) and after touring (o) australia and new zealand. values are expressed as means ± 95% ci. the number of matches analysed are: sharks n = 24 before, n = 27 after; stormers n = 19 before, n = 25 after; cats n = 29 before, n = 25 after; bulls n = 24 before, n = 30 after. p o in ts d if fe re n c e sajsm vol 19 no. 1 2007 21 pg20-22.indd 21 4/4/07 10:55:43 am 22 sajsm vol 19 no. 1 2007 after, travelling. this is in agreement with other studies, 5,13,14 which found that travel factors like crossing more time zones and having more days off, accounted for less than 1.5% of the variance in home advantage in baseball and hockey. courneya and carron 6 concluded that effects of travel on the home ground advantage are minimal for professional ranks, and later gayton and coombs 8 showed that the hypothesis applies for amateur sports as well. the concern and potential problem for super 12 rugby players is the possible effect of ‘jet lag’ on their home ground advantage. pace and carron 13 have documented that the severity of ‘jet lag’ and subsequent recovery is a function of the number of time zones crossed and the direction of travel, with the body readjusting and acclimatising faster for travel in a westbound direction. when returning from australia and new zealand south african teams travel in a westbound direction. thus home ground advantage is less affected by travel than if they had to travel home in an eastbound direction. 9 the findings of the study therefore suggest that westbound travel after being away for 4 5 weeks had no measurable effect on home ground advantage for the south african super 12 teams. based on these findings, playing more rugby matches at home in the super 12 competition (and the current super 14 competition) increased a team’s chance of doing well in the competition. as there were 12 teams in the tournament, some teams had 6 home and 5 away matches whereas other teams had 5 home and 6 away matches. therefore, all other factors being equal, the teams with 6 home matches should have had an advantage. an analysis of the data in this study should be interpreted in the context that teams in the super 12 tournament (and the current super 14 competition) vary from year to year. further research is required to explain the perceived problem of the south african teams generally underperforming in this tournament compared with the australian and new zealand teams. acknowledgements the medical research council and the nellie atkinson and harry crossley research funds of the university of cape town supported this study. references 1. balmer nj, nevill am, williams m. home advantage in the winter olympics (1908-1998). j sports sci 2001; 19: 129-39. 2. batterham am, hopkins wg. making meaningful inferences about magnitudes. international journal of sports physiology and performance 2006; 1: 50-7. 3. butler jl, baumeister rf. the trouble with friendly faces: skilled performance with a supportive audience. j pers soc psychol 1998; 75: 1213-30. 4. carron av, loughhead tm, bray sr. the home advantage in sport competitions: courneya and carron’s (1992) conceptual framework a decade later. j sports sci 2005; 23: 395-407. 5. courneya ks, carron av. effects of travel and length of home stand/road trip on the home ground advantage. journal of sport and exercise psychology 1991; 13: 42-9. 6. courneya ks, carron av. the home advantage in sport competitions: a literature review. journal of sport and exercise psychology 1992; 14: 2839. 7. du preez m, walpole b. home ground advantage fact or fallacy? a comment on the 2004 super 12 rugby competition. south african journal of sports medicine 2004; 16: 19-21. 8. gayton wf, coombs r. the home advantage in high school basketball. percept mot skills 1995; 81: 1344-6. 9. jehue r, street d, huizenga r. effect of time zone and game time changes on team performance: national football league. med sci sports exerc 1993; 25: 127-31. 10. morton hr. home advantage in southern hemisphere rugby union: national and international. j sports sci 2006; 24: 495 9. 11. nevill am, holder rl, bardsley a, calvert h, jones s. identifying home advantage in international tennis and golf tournaments. j sports sci 1997; 15: 437-43. 12. nevill am, holder rl. home ground advantage in sport: an overview of studies on the advantage of playing at home. sports med 1999; 28: 22136. 13. pace a, carron av. travel and the national hockey league. canadian journal of sports sciences 1992; 17: 60-4. 14. pollard r. home advantage in soccer: a retrospective analysis. j sports sci 1986; 4: 237-48. 15. recht ld, lew ra, schwartz wj. baseball teams beaten by jet lag. nature 1995; 377: 583. 16. snyder ee, purdy da. the home advantage in collegiate basketball. sociology of sport journal 1985; 2: 352-6. 17. wallace hm, baumeister rf, vohs kd. audience support and choking under pressure: a home disadvantage? j sports sci 2005; 23: 429-38. 18. waterhouse j, reilly t, edwards b. the stress of travel. j sports sci 2004; 22: 946-66. 19. wright ef, jackson w. the home-course disadvantage in golf championships: further evidence for the undermining effect of supportive audiences on performance under pressure. journal of sport behavior 1991; 14: 5160. 20. wright ef, voyer d. supporting audiences and performance under pressure: the home-ice disadvantage in hockey championships. journal of sport behavior 1995; 18: 21-8. pg20-22.indd 22 4/4/07 10:55:43 am 46 sajsm vol 19 no. 2 2007 introduction at the beginning of the new millennium professional rugby was confronted by several important challenges, one of the biggest being the increasing incidence rate of rugby injuries. 3,12,28 the tendency for an unacceptable increase in the rate of injuries is also visible at south african school level. 13,24 the question has already been asked if the elite senior school player has the anthropometric composition, physical and motor abilities, as well as sport-specific skills demanded by the modern game. 6,7,22 most school coaches, advocates of talent development and selectors put a high priority on the above abilities and implement programmes to develop bigger, stronger, faster and more skilful players who can excel at their sport. 6,8,23 however, these programmes do not place enough emphasis on the prevention 15,20,23,30 and rehabilitation 5,12,16 of previous injuries. consequently, the rate of injuries at senior-school level may continue to increase unless preventive measures – sufficient for the modern game – are adopted. to date, the authors are unaware of other studies that have evaluated the effectiveness of an injury prevention programme in decreasing the prevalence of high school rugby injuries. therefore the aim of this study was to determine whether an approved injury prevention programme has an effect on the rugby injuries (overall, intrinsic and extrinsic original research article effect of a prevention programme on the incidence of rugby injuries among 15and 16-year-old schoolboys abstract objective. the primary aim of this study was to determine the effect of an injury prevention programme on the incidence of rugby injuries (overall, intrinsic and extrinsic injuries) among 15and 16-year-old schoolboys, over a 2year period. a secondary aim was to identify the percentage of intrinsic rugby injuries associated with a previous injury history. design. a non-equivalent experimental-control group design with multiple post-tests. subjects. aand b-team rugby players (n =120) from 2 secondary schools in the north west province of south africa. intervention. the injury prevention programme was planned according to the physical, motor, biomechanical and postural status of all players. players in the experimental group received exercises to improve biomechanical and postural deficits identified, as well as drills to address shortcomings in speed, agility, and explosive power. main outcome measures. rugby injuries were screened and injury data collected through the use of weekly sportsmedicine clinics. results. differences and changes in extrinsic injury incidence in this study could not be attributed to the effect of the prevention programme, and as a result injury trends related to overall injury incidence were inconsistent when the matching experimental and control groups were compared. however, the prevention programme did have a positive effect on the intrinsic injury incidence of both the correspondence: e j spamer school for continuing teachers’ education north-west university: potchefstroom campus private bag x6001 potchefstroom, 2520 tel: 018-299 1611 fax: 018-299 4312 e-mail: manie.spamer@nwu.ac.za 15(d = 1.61) and 16-year-old (d = 0.83) groups during the study period. during the second season there were no intrinsic injuries of a previous nature among both the experimental groups (0%), while in contrast intrinsic injuries of a previous nature still amounted to a significant fraction in both the control groups. conclusion. the present intervention programme did not have a practically significant effect on the incidence of overall rugby injuries and extrinsic rugby injuries in 15and 16-year-old schoolboys over a 2-year period. however, in practice the prevention programme did have a significantly positive effect on the incidence of intrinsic rugby injuries among 15and 16-year-old schoolboys over a period of 2 years. timely introduction of this programme during the off-season is advised. h erasmus (msc (biokinetics), phd) e j spamer (phd) school for continuing teachers’ education, north-west university, potchefstroom campus pg46-51.indd 46 7/5/07 10:37:49 am sajsm vol 19 no. 2 2007 47 injuries) of 15and 16-year-old schoolboys. a secondary aim was to identify the percentage of intrinsic rugby injuries associated with a previous injury history in this group. methods a non-equivalent experimental-control group design with multiple post-tests was used in this study. the subjects (n = 120) were all schoolboy rugby players from 2 secondary schools in the north west province in 2004. both schools were involved with the rugby institute of the north-west university (nwu) (formerly known as puk rugby institute) and had coaches with a similar background and experience which ensured that the teams selected were coached similarly and according to the technical and fitness guidelines supplied by the nwu rugby institute. players who participated in the experimental injury prevention programme were the 15and 16-year-old elite a teams (n = 60). the b teams (n = 60) acted as controls. this intervention programme was assigned to a team (cluster), not an individual player, because schools wanted all their a-team players to be part of the prevention programme. furthermore, although a randomised study of individual players and their training practices often provides more realistic results, this may prove difficult for team sports like rugby, as these sports involve different player positions, each with its own exposure to accident hazards (injury risk) and physical demands. in addition, differences even exist between individuals in the same position; for example two a-team loose forwards with different work rates might not run the same distance during a match. this is complicated even more by the role that chance plays in occurrence of extrinsic injuries. however, by using whole teams as the study population, this study was able to meet the research requirements for players of similar age and physical condition participating in a programme with similar exposure to accident hazards and physical demands. the testing began once the schools and parents had given their approval. players were evaluated over a 2-year period. during each of the 2 years there were 3 testing occasions – pre-season, during the mid-season break and at the end of the season – where the (i) biomechanical and postural and (ii) physical and motor status of all players were evaluated. the prevention programme was written and adjusted according to the deficiencies identified in the abovementioned tests. on the day of testing the players rotated between different testing stations. the testing sequence and rest periods between tests were developed in such a way that no previous test would influence subsequent tests. in addition, injury information was gathered weekly through the use of sports medicine clinics and questionnaires. injury definitions for the purposes of the study the following definition by garraway and macleod 4 was used to define a reportable rugby injury: ‘an injury sustained on the field during a competitive match or during training, or during other training activities directly associated with rugby, which prevented the player from playing or training from the time of injury or from the end of the match or training session in which the injury was sustained’. re-injury was defined as an identical injury sustained at least 1 month after the return to the sports activities. 17 a previous injury was described as a positive history of injury in the 12 months prior to the start of the season. 10 the injury incidence reported in this study is expressed in terms of injuries/1 000 player hours. 4 injuries were divided into 2 types, namely intrinsic and extrinsic injuries. intrinsic injuries were injuries associated with repetitive overuse of the body. 21 extrinsic (external trauma) injuries were caused by external forces applied directly to the body by someone or something. 21 the overall injuries were determined as the sum of the intrinsic and extrinsic injuries. sports medicine clinics injuries were screened and injury data collected through the use of free sports medicine clinics. clinics were held once a week, either on the monday after a rugby match or during the rest of the week (usually wednesdays). each clinic was staffed by a qualified sports physician (medical practitioner specialising in sports injuries) or physiotherapist, biokineticist (specialist in preventive and rehabilitative exercise) and sport scientist (fitness and conditioning specialist, if available). the functions of the clinics were to diagnose, refer (to the player’s doctor, physiotherapist, biokineticist or sport scientist) and manage all players who reported an injury. information relating to the injuries were extracted from these medical records after the end of each rugby season. questionnaires before injured players were screened, they had to complete a current and previous injury and rehabilitation information questionnaire. 2,10 during the sports medicine clinic the injured player and medical staff completed a relevant injury report form for each injury. 2 these forms were used to register and categorise all rugby injuries. battery of tests the tests and protocols used for the purposes of this article were chosen from the literature, and their usefulness had been proved in previous studies. 6-8,10,22,31 these tests were divided into 2 main groups: a biomechanical and postural, and a physical and motor group. the biomechanical and postural evaluation used a recent approach that measures a combination of muscle and joint symmetry, dynamic mobility and local stability. 10 measurements were chosen from common clinical measures of posture and flexibility that could easily be used in a standard biomechanical and postural screening. the biomechanical and postural assessment protocol 2 (81 measurements in pg46-51.indd 47 7/5/07 10:37:49 am 48 sajsm vol 19 no. 2 2007 total) evaluated 5 different zones, namely lower limb (knee complex, hip joint, foot), pelvic girdle, spinal column, upper limb (shoulder complex) and neurodynamics. no warm-up exercises were done before the biomechanical and postural evaluation. for the test protocol subjects were dressed in rugby shorts. all tests were completed indoors. one examiner was used to perform the test procedure and an observer/recorder assisted with measurements. 2 the recorder also served to verify the accuracy of measurement and measurement sequence. the examiner and observer were properly briefed on each individual test procedure and for consistency the same 2 trained medical personnel were used for all tests. during the study all tests were repeated on the left and right-hand side of the subject’s body. because players also received exercises to improve their speed, agility and explosive power, the physical and motor tests administered were the following: the 10 m and 30 m dash for speed, 11 the illinois agility run 14 and vertical jump 14 for explosive power. however, as the aim of this article was to discuss results on rugby injuries, a discussion of the results of the various biomechanical and postural, and physical and motor tests does not fall within its scope. the overall methodology used in each specific test, as well as the test results have been described in the study by erasmus. 2 prevention programmes players were given general prevention programmes to address the specific biomechanical and postural, and physical and motor deficits identified on each testing occasion. in order to optimise conditioning results and prevent overtraining, the prevention programme had to be structured into different cycles, i.e. it had to be periodised. for the purposes of this study, the annual training period was organised into 7 different phases – each phase immediately following the previous one. the 7 phases were as follows: 1. pre-season programme (3-week preparation programme starting 3 weeks before the first school game). 2. start-of-season programme level 1 (6-week maintenance programme). 3. start-of-season programme level 2 (advanced maintenance programme). 4. mid-season programme (1-week conditioning programme starting 1 week before the end of the mid-season break). 5. mid-season programme level 3 (most advanced conditioning programme). 6. post-season transition programme (3 weeks of active rest, recovery and corrective biomechanical/postural exercise following the last game). 7. off-season programme (low-key programme followed until the start of the pre-season programme, ± end of january). exercises in the same phase were of similar difficulty and intensity, with a gradual increase in difficulty and intensity during the season. phases 1 and 4 were programmes with a higher volume but lower intensity than the phases that followed them (aim: to regain some lost condition and prepare for the more difficult levels that follow). number 7 is a low-volume maintenance programme. levels 1 3 (numbers 2, 3 and 5) are programmes lower in volume than numbers 1 and 4, but higher in level of difficulty (the difficulty rises progressively from level 1 to level 3, with the latter being the most difficult of the 3). a detailed discussion of each phase of the prevention programme can be found in the study by erasmus. 2 implementation of exercises descriptions and pictures of all the exercises used in the study are given in the study by erasmus (totalling ± 60 pages of exercise pictures plus descriptions). 2 at the start of each season, the coaches and team captains of the relevant teams were educated on the use of the prescribed exercises by the first author (he). each experimental group was then provided with an instructional booklet. the author demonstrated all relevant exercises to the players before the start of each training phase. the author visited teams at least twice a week to monitor exercise technique and supervise exercise sessions. on the remaining 2 or 3 days of the week, training was supervised by the coach and team captain. the players did the relevant exercises on their own on days when there was no official training. exercises were incorporated into the warm-up and cool-down periods of normal rugby training. the teams all followed their own warm-up of 15 minutes to produce mild sweating without fatigue. generally, active movements were used to prepare all the major muscle groups for activity, while more sport-specific warm-up movements were used to concentrate on the muscle groups that were expected to be used in the specific day’s rugby training activity. after this 15-minute warm-up session, the prescribed exercises commenced. this continued for 20 minutes. immediately after training, each coach allowed for a period of active cooldown to provide the body with a period of adjustment from exercise to rest. the length of the cool-down varied from 10 to 20 minutes and included jogging and walking, as well as the remaining preventive exercises. certain exercises that required weights or other gymnasium apparatus were completed as a daily home exercise programme (this constituted a small part of the total programme). subjects could choose to complete these exercises either at home, in the school gymnasium, at the local gymnasium or at the injury rehabilitation centre (biokinetics centre) of their choice. subjects were asked to report their home exercise compliance by noting the days they performed the complete prescribed exercises on a log and to report their compliance weekly. if subjects performed their exercises on fewer than 70% of the required days, they were not included in the study. to promote honesty, the subjects were allowed continued guidance in their exercise programmes, even in the case of non-compliance. to control the effect that other pg46-51.indd 48 7/5/07 10:37:49 am sajsm vol 19 no. 2 2007 49 resistance training might have on the effect of the prevention programme, all experimental and control groups of players followed the basic age-specific resistance programme of the nwu rugby institute in the gymnasium. statistical methods data were analysed using the statistica-7 program. 26 descriptive statistics, and effect sizes (practical significance) were used. 1,29 the groups in this study were not chosen randomly (non-equivalent groups), therefore the t-test could not be used to determine the statistical significance of differences in injury incidences. therefore, only effect sizes (practical significance of differences) 1,27 were used to describe the differences that occurred. results injury incidence mean injury rates for the different groups are shown in table i. the mean intrinsic injury incidence experienced by the 15year-old experimental group during the total period (2 years) was 0.74 injuries/1 000 player-hours, which is significantly (d = 1.61) less that the mean value of 1.98 experienced by the 15-year-old control group (table i). regarding the 16-yearold players, data during the total period mirrored that of the 15-years-olds, once more finding a high practically significant (d = 0.83) difference. considering the extrinsic injury incidence reported during this study (table i), the results for the 2-year period indicate that both the 15and 16-year old experimental groups experienced significantly more (d = 1.56 and d = 0.85) extrinsic injuries than the corresponding control groups. the mean overall injury results for the total period indicate that the 15-year-old experimental group experienced 3.99 injuries/1 000 player-hours, which is lower than the mean value of 4.75 experienced by the 15-year-old control group. in practice, this difference (d = 0.74) is not highly significant. this tendency seen in the 15-year-olds (lower overall injury incidence among the experimental group) was not shared by the 16-year-olds. no difference was found between the overall injury incidence experienced by the two 16-yearold groups during the total period, as both the 16-year-old experimental and the 16-year-old control group experienced 3.17 injuries/1 000 player-hours. intrinsic injuries with a previous injury history the possible influence of previous injuries (injuries during the previous 12 months) on the intrinsic injury incidence is shown in table ii. among the 16-year-old experimental group, 100% of intrinsic injuries during the first season were of a previous nature, compared with 33% in the corresponding control group. a similar pattern is visible in the 15-year-old groups, during the first season. thus, during the first season it is clear that the majority of intrinsic injuries experienced by all the experimental and control groups – with the exception of the 16-year-old control group – were of a previous nature. during the second season a different pattern was evident. it is apparent that among both the experimental groups there were no intrinsic injuries of a previous nature visible (0%), while in contrast to this intrinsic injuries of a previous nature still amounted to a significant fraction in both the control groups. discussion injury incidence firstly, it must be noted that a-team players are normally expected to sustain more overall injuries than players in the lower teams. 20,24 likewise, players in the a teams are at increased risk of sustaining intrinsic injuries, as a result of factable i. descriptive statistics of injury incidence during the 2-year study and d-values (effect sizes) of the intergroup comparisons intrinsic incidence extrinsic incidence overall incidence (injuries/1 000 player hours) (injuries/1 000 player hours) (injuries/1 000 player hours) group total period total period total period mean ± sd mean ± sd mean ± sd 15-year-old experimental group (n = 30) 0.74 ± 0.52 3.24 ± 0.11 3.99 ± 0.57 15-year-old control group (n = 30) 1.98 ± 0.77 2.77 ± 0.30 4.75 ± 1.03 inter-group difference (d-value) 1.61* 1.56* 0.74 16-year-old experimental group (n = 30) 0.14 ± 0.21 3.02 ± 1.24 3.17 ± 1.43 16-year-old control group (n = 30) 1.21 ± 1.29 1.96 ± 0.23 3.17 ± 1.48 inter-group difference (d-value) 0.83* 0.85* 0.00 * large practically significant inter-group difference (d-value > 0.8) between experimental and control group of same age. sd = standard deviation. pg46-51.indd 49 7/5/07 10:37:49 am 50 sajsm vol 19 no. 2 2007 tors such as increased pressure to perform at a-team level, as well as the fact that matches are more demanding. 9,19,21 similarly, because of the increased intensity with which the game is played at a-team level, these players are at greater risk of sustaining extrinsic (related to trauma) injuries than players in the b teams. 21,23 however, in the present study the experimental groups (a teams) were the teams receiving the intervention and were therefore expected to experience a reduction in overall injury incidence. it was expected that the prevention programme would reduce intrinsic injuries (related to overuse) among the experimental groups, as these injuries are related to factors such as poor biomechanics and overuse, which can be prevented. 18,21 the results of this study show that in practice the 15and 16-year-old groups which had the injury prevention programme had significantly fewer intrinsic injuries than the corresponding control groups. the success of the prevention programme in reducing intrinsic injury incidence is most likely due to the positive effect of the prevention programme on the biomechanical and postural variables 2 of the experimental groups. the fact that the extrinsic injury incidence experienced by both the 15and 16-year-old experimental groups in this study remained significantly more than that of the corresponding control group illustrates the inability of the prevention programme to reduce the extrinsic injury incidence experienced by the experimental groups to below that of the control groups. this may be attributed to the fact that the prevention programme was not designed to reduce extrinsic injury incidence, 2 as there are too many unpredictable elements (associated with contact situations) present in the occurrence of these injuries. 21 this study showed that the prevention programme did not reduce the overall injuries of the 15and 16-year-old experimental group to significantly below the injury incidence in the corresponding control groups. this may be explained by the fact that factors such as aging, 15,21 level of play 20,21,24,25 and pressure to perform 19 may have led to inconsistencies in extrinsic injury incidence. in turn these changes in extrinsic injury incidence during the 2 years may be responsible for the incoherent pattern detected in the overall injury incidence, seeing that overall injury incidence consists of the sum of the intrinsic and extrinsic injury incidence. intrinsic injuries with a previous injury history the percentage of intrinsic injuries with a chronic nature are shown in table ii. these results signify that during the first season of intervention, intrinsic injuries of a previous nature remained a dilemma, even in the presence of the prevention programme. this could suggest that these injuries were not fully rehabilitated before the start of the study, or that the causes of these injuries were not removed completely during the first season of the study. during the second season a different pattern emerged. it is evident that among both the experimental groups there were no intrinsic injuries of a previous nature visible (0%), while in contrast to this intrinsic injuries of a previous nature still amounted to a significant fraction in both the control groups. this could have been due to the rehabilitative effect of the prevention programme, as this programme is specifically aimed at reducing biomechanical shortcomings in the experimental groups. therefore it can be concluded that during the second season the prevention programme possibly had a more significant effect on shortcomings due to previous injuries. to the best of the authors’ knowledge this finding has not been investigated by previous studies. this pattern during the second season suggests that the programme restored certain impaired functions, and therefore had more of a rehabilitative than a preventive effect during the first season. because of this certain deficiencies were overcome, and the programme could reach its preventive potential during the second year. conclusions the prevention programme used in this study had a positive effect on the intrinsic injury incidence of 15and 16-yearold schoolboy rugby players, particularly during the second year of study after the programme had been implemented for 1 year. therefore this prevention programme can serve as a model for the reduction of future intrinsic rugby injury incidence among 15and 16-year-old schoolboys, as well as a basis for further study on the prevention of rugby injuries among senior schoolboys. references 1. ellis sm, steyn hs. practical significance (effect sizes) versus or in combination with statistical significance (p-values). management dynamics 2003; 12: 51-3. 2. erasmus h. the effect of a prevention programme on the rugby injuries of 15and 16-year old schoolboys. phd thesis, potchefstroom university, 2006. 3. garraway wm, lee aj, hutton sj, russell eb, macleod da. impact of professionalism on injuries in rugby union. br j sports med 2000; 34: 348-51. 4. garraway m, macleod d. epidemiology of rugby football injuries. lancet 1995; 345: 1485-7. 5. gerrard df, waller ae, bird yn. the new zealand rugby injury and performance project, ii: previous injury experience of a rugby-playing cohort. br j sports med 1994; 28: 229-33. table ii. percentage of intrinsic injuries recorded as previous injuries in the experimental and control groups of rugby players during each season intrinsic injuries with previous history (as % of total number of intrinsic injuries) group season 1 season 2 15-year-old experimental group 80 0 (no intrinsic injuries) 15-year-old control group 60 40 16-year-old experimental group 100 0 (no intrinsic injuries) 16-year-old control group 33 60 pg46-51.indd 50 7/5/07 10:37:50 am sajsm vol 19 no. 2 2007 51 6. hanekom aj. anthropometriese, fisieke, motoriese en vaardigheidseienskappe van senior sekondêre skoolrugbyspelers in die noordwesprovinsie. ma thesis, potchefstroom university, 2000. 7. hare e. die identifisering van rugbytalent by seuns in die senior sekondêre skoolfase. med thesis, potchefstroom university, 1997. 8. hare e. longitudinale studie van talentvolle jeugrugbyspelers met verwysing na vaardigheid, groei en ontwikkeling. phd thesis, potchefstroom university, 1999. 9. harvey js. overuse syndromes in young athletes. clin sports med 1983; 2: 595-607. 10. hattingh jhb. a prevention programme for rugby injuries based on an analysis among adolescent players. phd thesis, potchefstroom university, 2003. 11. hazeldiner r, mcnab t. the rfu guide to fitness for rugby. london: a & c black, 1998. 12. holtzhausen lj. the epidemiology of injuries in professional rugby union in south africa. mphil thesis, university of cape town, 2001. 13. jakoet i. contrast injuries in schoolboy rugby. south african sports medicine association congress, johannesburg, 2002. 14. kirby rf. kirby’s guide to fitness and motor performance tests. cape girardeau: ben oak publishing company, 1991. 15. lee aj, garraway wm. epidemiological comparison of injuries in school and senior club rugby. br j sports med 1996; 30: 213-7. 16. lee aj, garraway wm, arneil dw. influence of preseason training, fitness, and existing injury on subsequent rugby injury. br j sports med 2001; 35: 412-7. 17. lynsens rj, de weerdt w, niewboer a. factors associated with injury proneness. sports med 1991; 12: 281-9. 18. mcginnis pm. biomechanics of sport and exercise. 2nd ed. champaign, ill: human kinetics publishers, 2005. 19. micheli lj. overuse injuries in children’s sports: the growth factor. orthop clin north am 1983; 14: 337-60. 20. nathan m, goedeker r, noakes td. the incidence and nature of rugby injuries experienced at one school during the 1982 rugby season. s afr med j 1983; 64: 132-7. 21. noakes td, du plessis m. rugby without risk: a practical guide for the prevention and treatment of rugby injuries. pretoria: jl van schaik, 1996. 22. plotz af. ’n vergelykende studie van suid-afrikaanse en engelse adolessente eliterugbyspelers met verwysing na spelspesifieke, antropometriese en fisiek-motoriese veranderlikes. med thesis, potchefstroom university, 2004. 23. quarrie kl, handcock p, toomey mj, waller ae. the new zealand rugby injury and performance project. iv. anthropometric and physical performance comparisons between positional categories of senior a rugby players. br j sport med 1996; 30(1): 53-5. 24. roux ce. the epidemiology of schoolboy rugby injuries. msc thesis, university of cape town, 1992. 25. roux ce, goedeke r, visser gr, van zyl wa, noekes td. the epidemiology of schoolboy rugby injuries. s afr med j 1987; 71: 307-13. 26. statsoft inc. statistica. data analysis software system, version 7, 2005, www.statsoft.com. 27. steyn hs jun.. practical significance of the difference in means. journal of industrial psychology 2000; 26(3): 1-3. 28. targett sg. injuries in professional rugby union. clin j sport med 1998; 8: 280-5. 29. thomas jr, nelson jk. research methods in physical activity. 4th ed. champaign, ill.: human kinetics, 2001. 30. upton pa, roux ce, noakes td. inadequate pre-season preparation of schoolboy rugby players. a survey of players at 25 cape province high schools. s afr med j 1996; 86: 531-3. 31. van gent mm. a test battery for the determination of positional requirements in adolescent rugby players. phd thesis, potchefstroom university, 2003. current diagnosis & treatment: sports medicine author: patrick j mcmahon august 9, 2006; paperback; 624 pages 0071410635 / 9780071410632 readable. comprehensive. up-to-date. the one book to have for day-to-day answers in sports medicine.  authoritative, point-of-care coverage with evaluation, treatment, and management of all common sports injuries  essential evidence-based stabilization and rehabilitation techniques  prevention strategies featured throughout  pre-participation and on -the-field evaluation  practical guidance on sports injuries in children  coverage of the medical issues of female athletes  in -depth treatment of concussion  up-to -date information on medical conditions and sports participation  numerous easy-to -read diagnostic charts, tables, and treatment graphs  concise, current, and comprehensive review of the biomechanics of sports medicine  helpful references to classic and important new sources  online updates at companion site currentmed.com pg46-51.indd 51 7/5/07 10:37:50 am introduction sleep functions to conserve energy, restore body tissue and downregulate body temperature. in comparison, exercise depletes energy stores, causes tissue breakdown and increases body temperature. 1,2 therefore, one might assume that exercise would promote and improve sleep quality, 2 and could even be used as a non-pharmacological way of improving sleep. 1 however, exercise variables such as type, intensity, duration and timing, as well as individual variables such as age, gender, body mass and fitness, all influence the relationship between exercise and sleep. 1 the intensity and duration of exercise seem to be the most influential factors affecting sleep. 2 exercise of moderate intensity has been shown to improve self-reported or subjective measures of sleep. 3 in comparison, high-intensity, strenuous exercise may result in disrupted sleep. 4 driver et al. 5 proposed that each individual has a threshold of duration and intensity of exercise. once this threshold is exceeded, sleep is negatively affected by the exercise. possibly the most physically taxing exercise events are multiday stage races of either cross-country skiing, running, road cycling, mountain biking or adventure racing. in these long-duration events, participants are required to exercise for several hours per day, and often for three or more consecutive days. in these types of exercise events you might expect a detrimental impact on sleep as a result of the long duration and often the high intensity of the exercise. in addition, competitors partaking in such events often sleep in different environments each night, and so the unfamiliar and possibly uncomfortable sleeping environments also may disturb their sleep. to our knowledge, the effects of repeated endurance exercise on sleep have not yet been studied. studies have been done on competitors in very long-duration events, such as ultra-triathlons, but these events take place on only one day. 5 since stage racing is becoming more popular as a competitive event, it is important to investigate the effects that the repeated endurance exercise may have on sleep, as adequate sleep is crucial for recovery, physical well-being and exercise performance. 1 therefore, the aim of our study was to determine the effect of repeated sub-maximal-intensity mountain biking, over three consecutive days, on the sleep of trained mountain bikers. we chose to assess the mountain bikers’ sleep both objectively, using activity data loggers (actigraphy) as a measure of movement during the night, and subjectively, using questionnaires and visual analogue scales. to isolate the effect of the exercise on sleep and eliminate the effect of the sleeping environment, the study participants slept at home in their normal environment. original research the effects of three days of sub-maximal-intensity mountain biking on sleep abstract objectives. we determined the effect of three consecutive days of sub-maximal-intensity mountain biking (4.5 hours per day, ~64 km per day), on the sleep of ten healthy, trained male and female mountain bikers. methods. the sleep of the mountain bikers was assessed both subjectively (visual analogue scales and sleep questionnaires) and objectively (activity data logger) on each night of mountain biking and for seven nights when they were not cycling (pre-exercise, mean of seven nights). the cyclists’ mood and muscular pain were assessed each night using visual analogue scales. the cyclists slept at home in their normal environment. results. there was no significant difference between the mountain bikers’ muscular pain and mood (calm/anxious visual analogue scale) measured during the pre-exercise stage and their pain and mood measured on each of the mountain biking nights (p>0.05). however, compared with the pre-exercise stage, the mountain bikers reported that they were significantly more tired (tired/energetic visual analogue scale) on each night of cycling (p<0.01). the sleep of the mountain bikers was disrupted on the night of the third day of mountain biking only. on this night, compared with the pre-exercise stage, the mountain bikers reported that they woke up more during the night (double the number of times) (p<0.001), and an activity data logger recorded that they were awake for about half an hour longer during the night (p<0.05). conclusion. we have shown that three days of repeated, endurance sub-maximal mountain biking disrupted the sleep of the mountain bikers on the third night of cycling. correspondence: ingrid avidon school of physiology university of the witwatersrand medical school 7 york road parktown, 2193 south africa tel: +27 11 717-2363 fax: +27 11 643-2765 e-mail: ingrid.avidon@wits.ac.za stephanie p murphy (bsc honours, physiology) andrea fuller (phd) alison j bentley (phd) ingrid avidon (phd) school of physiology, university of the witwatersrand medical school, faculty of health science, johannesburg sajsm vol 23 no. 1 2011 3 methods ethical clearance ethical clearance was obtained from the university of the witwatersrand’s committee for research on human subjects, which adheres to the principles of the declaration of helsinki (m080447); all the subjects gave written informed consent for participation. subject recruitment mountain bikers from mountain biking clubs in and around johannesburg and pretoria, south africa, were asked to volunteer for the study. comprehensive questionnaires were used to determine whether the subjects were healthy and sufficiently trained to participate safely in the study. volunteers had to have been cycling for at least three years and training (cycling) at least six hours per week to be eligible for the study. volunteers were excluded from the study if they were not healthy, or if they were not sufficiently trained to complete three consecutive days of mountain biking lasting four hours per day. thereafter, the volunteers were screened for sleep disorders using the pittsburgh sleep quality index (psqi) and screened for depression using a general health questionnaire. volunteers who scored more than 5 on the psqi, an indication of disturbed sleep, 6 and volunteers who were depressed, were excluded from the study. furthermore, volunteers were excluded from the study if they did not have a normal sleep routine or if they had a lifestyle or occupation that did not allow for a normal sleep routine. after screening, ten mountain bikers met all the inclusion criteria and participated in the study. subject characteristics eight males and two females (n=10) between the ages of 20 and 52 years, with an average age of 37±9 years, participated in the study. the mountain bikers had a mean ± sd height of 1.75±0.04 m, a mean weight of 76.8±8.9 kg and a mean body mass index (bmi) of 22.9±2.0 kg.m -2 . all subjects were competent, trained riders who had been participating in mountain biking for at least three years and who were cycling at least six hours per week (range: 6 10 hours per week). within the last year, five of the riders had participated in three competitive stage races lasting more than three days; three of the riders had participated in two competitive stage races lasting more than three days; and two had participated in one competitive stage race lasting more than five days. experimental design the study was done in two stages – a pre-exercise stage and a mountain biking stage. during both stages, objective and subjective measures of sleep were recorded using actigraphy (activity data logger) and questionnaires, respectively. on each night of the two stages the mountain bikers were asked to wear the activity data logger on their right arm (see ‘objective measure of sleep’ below). the activity data logger detects movement during sleep and is an objective measure of disrupted sleep. in addition, the mountain bikers were asked to complete questionnaires before going to bed and then again in the morning (see ‘subjective measures of sleep, pain and mood’ below). the pre-exercise stage consisted of seven days and nights with no change to the normal exercise or sleep patterns of the riders. this stage was used to establish each subject’s normal sleep, pain and mood patterns. the mountain biking stage consisted of three consecutive days in which the riders performed 4.5 hours of mountain biking each day at the groenkloof nature reserve, pretoria (1 308 m above sea level), on a marked mountain biking trail within the reserve. the terrain of the trail was hilly and rocky and the cycling was performed in late august until early september (spring). the riders were asked to consume their ‘normal training day’ breakfast on the mornings of mountain biking, and follow a high-carbohydrate diet for the three days of cycling. before the start of the ride, each rider’s maximum heart rate was estimated at 220 minus their age. 7 each rider wore a heart rate monitor (polar heart rate monitor s610, polar electro oy, kempele, finland) for the duration of the ride and was asked to maintain a heart rate of between 70% and 80% of their estimated maximum. exercise intensity has been shown to affect sleep, and therefore the riders were asked to cycle at a set intensity in order to standardise the exercise intensity between the riders over the three days. the mountain bikers started riding by 08h30 every morning, and rode continuously for 4.5 hours. they were allowed to drink water and their chosen energy drink ad lib during the cycling. in addition, each cyclist was given three pvm energy bars (pvm nutritional sciences, pretoria, south africa; carbohydrate 27 g/bar; protein 5.3 g/bar; fat 5.5 g/bar) and instructed to eat one bar every 90 minutes. at the end of riding, the distance and time for each rider were recorded from their bicycle computer. at the end of each day, each rider was asked to use the 10-point borg scale to rate their perceived exertion (rpe) for the ride. the riders returned home after each day of mountain biking and slept in their normal sleeping environment. the riders were encouraged to begin fluid and carbohydrate replenishment as soon as possible after riding and eat a high-carbohydrate diet during the day. all objective and subjective data related to sleep, mood and pain were analysed on the nights after the exercise days. on each day of the mountain biking, the microclimate was measured at 30-minute intervals throughout the cycling time. the wet and dry bulb temperatures, black globe temperature and wind speed were recorded to determine whether all the mountain bikers had exercised under similar environmental conditions. during the study, the mountain bikers were asked to refrain from long-duration or intense exercise other than the three days of mountain biking, and to follow their normal daily activities and sleeping patterns. they were not allowed to drink alcohol and caffeinated beverages. they were asked not to use any pain medication or modalities such as massage or icing to decrease muscular pain. furthermore, they were not allowed to take naps during the day or take sleeping pills or medications/agents that could disrupt their normal sleep patterns. they were asked to follow their normal sleep patterns and refrain from activities that could disrupt sleep (e.g. working or socialising late into the night). objective measure of sleep on each night of the study, each subject wore an activity data logger (sensormedics, bodymedia ® body monitoring system – sensewear ® pro2 armband, milan, italy) on their upper right arm during sleep. the armband, an activity monitor with a 2-axis accelerometer, is able to detect movement in two planes, and has been validated as a sleep detection device. 8 the armband weighs approximately 200 g, is comfortable to wear and is not disruptive to sleep. the mountain bikers put the armbands on when they switched off the light with the intention of going to sleep and removed the armband when they woke up in the morning. the armband recorded and saved the data until it was downloaded at a later stage. based on the amount of movement detected by the armband during the night, the software calculated the total sleep time ((tst), minutes) of each subject and the amount of time he or she was awake during the night (wakefulness after sleep onset (waso), minutes). 4 sajsm vol 23 no. 1 2011 sajsm vol 23 no. 1 2011 5 subjective measures of sleep, pain and mood the subjects completed an evening form before going to bed to subjectively assess their muscular pain and mood. they were asked to indicate their current muscular pain on a 100 mm visual analogue scale (vas) anchored at ‘no pain’, and ‘worst pain ever felt’. they were also asked to indicate their current mood on two separate 100 mm vass – one anchored at ‘calm’ and ‘anxious’ and the other at ‘tired’ and ‘energetic’. 9 on each morning of the study, the subjects completed the wits dial-a-bed morning form within 20 minutes of waking up. they recorded the time they went to bed (lights off), the time they thought it had taken to fall asleep (sleep-onset latency (sol), minutes), the number of times they thought they had woken up during the night (number of awakenings), how long they thought they were awake during the night (waso, minutes), and the time they woke up in the morning. from this information we were able to calculate their time in bed ((tib), minutes) as the time from lights off to the time that they woke up in the morning, tst (minutes) as tib minus (sol + waso), sleep efficiency ((se), percentage) as tst/tib x 100. furthermore, the mountain bikers were asked to rate their sleep quality (sq) on a 100 mm vas line anchored at ‘worst sleep ever’ and ‘best sleep ever’. data analysis to establish the normal sleep variables, mood and pain for each subject, a mean of each of the variables was calculated from the preexercise stage. the vas data (pain, mood and sleep quality) were normalised with an arcsine transformation before parametric statistical analysis. a repeated-measures analysis of variance (rm anova) was used to determine whether there was a difference between muscular pain, mood and objective and subjective sleep variables measured in the pre-exercise phase (mean of pre-exercise nights) and on each night after the three mountain biking days. a dunnett’s multiple comparisons test was used as a post test to compare the mountain bikers’ pre-exercise pain, mood and sleep variables with the variables measured on each night of the three mountain biking days. the subject’s riding distance and riding speed on each day of mountain biking were compared using a rm anova, with a tukey post test. the rpe on each day of mountain biking was compared using the friedman test with a dunn post test. the data, except for the rpe (median, upper 95% ci, lower 95% ci), are expressed as mean ± sd. for all statistical analysis p<0.05 was considered significantly different. results mountain biking data on each day of mountain biking there was no difference in the riders’ reported rpe (p=0.75), riding distance (p=0.18, f=1.92) and average riding speed (p=0.07, f=3.21). the median (upper and lower 95% ci) rpe for the mountain bikers during the exercise stage was 5 (5; 6), the mean ± sd riding distance was 63.7±3.8 km and the mean ± sd riding speed was 14.4±0.6 km.h -1 . the mountain bikers rode under similar weather conditions. on all the riding days, the dry bulb temperature ranged from 6.5˚c in the morning (07h00) to 26˚c by 13h00. wet bulb temperature ranged from 6˚c in the morning to 19˚c at 13h00. black globe temperature ranged from 14.5˚c in the morning to 44.2˚c at 13h00. wind speed ranged from 0 to 5.3 m.s -1 . objective and subjective measures of sleep (pre-exercise versus mountain biking nights) the mountain bikers’ objective and subjective measures of sleep are given in table i. there were no significant differences between the pre-exercise and mountain biking nights for the riders’ subjective tib (p=0.54, f=0.66), tst (p=0.35, f=1.16), objective tst (p=0.52, f=0.65), subjective sol (p=0.54, f=0.73), subjective waso (p=0.56, f=0.69), subjective sq (p=0.56, f=0.71) and subjective se (p=0.24, f=1.51). there was a significant difference between the subjective number of awakenings reported by the mountain bikers during the pre-exercise and mountain biking nights (p=0.02, f=4.32, table i). compared with the pre-exercise stage, the mountain bikers reported that they woke up more on the night after the third day of mountain biking (p<0.001, table i), but not on the night after the first or second day of mountain biking (p>0.05, table i). there was a significant difference between objective waso recorded by the armbands on the pre-exercise and the mountain biking nights (p=0.05, f=2.92, table i). compared with the preexercise stage, objective waso was significantly increased on the night of the third day of mountain biking by more than 30 minutes (p≤0.05), but not on the night after the first (p>0.05) or second day (p>0.05) of mountain biking. table ii shows the number of subjects, out of ten, compared with baseline, who showed an increase, a decrease or no change in their sleep measures on each of the three nights. muscular pain and mood (pre-exercise versus mountain biking nights) the muscular pain and mood data for the mountain bikers are given in table i. there was no significant difference between the intensity of muscular pain experienced by the mountain bikers in the pre-exercise stage and after each of the mountain biking days (p=0.07, f=2.59, table i). there was no significant difference between the mountain bikers’ mood on the calm/anxious scale in the pre-exercise stage compared with the mountain biking nights (p=0.23, f=1.15, table i). however, there was a significant difference between the subjects’ mood on the tired/energetic scale when measured in the pre-exercise stage compared with the mountain biking nights (p=0.0016, f=6.48). compared with the pre-exercise stage, the subjects reported that they were significantly more tired at night on all three days of mountain biking (p<0.01, table i). discussion we assessed the sleep of mountain bikers, both objectively and subjectively, on two separate occasions: when they were not exercising (pre-exercise phase) and on each night of three consecutive days of mountain biking. our results show that three days of sub-maximalintensity mountain biking, for four and a half hours per day, disrupts sleep on the third night only. compared with the pre-exercise phase, on the night of the third day of mountain biking the riders reported that they woke up more often during the night and spent more than 30 minutes extra awake when measured by an activity data logger, worn during sleep as an objective measure of sleep (table i). we recruited ten mountain bikers with no sleep abnormalities who successfully fulfilled all the criteria for participation in the study and who were prepared to participate in the lengthy study protocol. however, our relatively small sample size may have resulted in the absence of significant change in some of the other objective and subjective sleep variables. the mountain bikers all rode the same mountain bike route at a similar rpe, for a similar time, at a similar time of day (and environmental conditions), at a similar speed, and with adequate energy provision. furthermore, all the subjects slept at home in their own beds each night, allowing us to remove extraneous factors such as environmental conditions, exercise intensity, exercise duration, inadequate nutrition and unaccustomed sleeping environment, which could affect sleep, from our investigation. the subjects were asked to record the time they went to bed and the time they woke up each morning. from this data we were able to calculate their tib. there was no significant difference in the tib data between the pre-exercise and cycling nights (table i), confirming that the subjects did keep to a regular schedule across the study. the mountain bikers were asked to ride each day at a similar sub-maximal heart rate and rpe, and not alter their intensity of riding which would occur if they were racing or allowed to set their own riding intensity. these findings mean that our data cannot be extrapolated to a real racing situation. similarly, the riders all rode under similar mild environmental conditions in the months of august to early september (spring). exercise performed in hot environmental conditions, unlike our riding conditions, can increase core body temperature. 10 an increased core body temperature can influence measures of sleep, 11 but has also been shown to have no effect on sleep. 6,12 therefore, in our study, we can only report on the effects of the riding on measures of sleep in mild environmental conditions and cannot extrapolate our data to warmer environmental conditions that may occur during summer months. we assessed the sleep in the mountain bikers both objectively and subjectively. the gold standard for objective sleep recording is polysomnography (psg). while psg may be a better method of recording sleep objectively, it would have added an additional unwanted component to the study, i.e. that of sleeping in a strange environment. therefore, for our objective assessment of sleep, we used an activity data logger to assess movement during sleep as a marker of disturbed or restless sleep. actigraphy is becoming a popular method of assessing total sleep time and movement during sleep, a measure of waso. 8,13,14 we also included a subjective sleep assessment in our study, as this form of assessment provides valuable information regarding an individual’s perception of their sleep. 15,16 furthermore, subjective sleep estimates tend to differ from objective measurements of sleep, 15,17,18 and therefore it is important for studies to include both assessments when investigating sleep. we hypothesised that the sleep of the cyclists would be disrupted as a result of the repeated mountain biking, becoming increasingly disrupted with each day of riding. we found that the sleep of the mountain bikers was disrupted only on the third night of exercise. on this night, compared with the pre-exercise nights, the cyclists reported that they woke up more often during the night (double the number of times) and their activity data loggers showed that they were awake for 34 minutes longer during the night (increased 6 sajsm vol 23 no. 1 2011 table i. mountain bikers’ objective and subjective measures of sleep, pain and mood for the pre-exercise phase and on each night of three consecutive days of mountain biking pre-exercise night 1 night 2 night 3 objective measure of sleep total sleep time (tst, min.) 400.2±30.6 [380.1-450.4] 350.8±28.3 [339.1-400.3] 371.1±20.5 [340.2 -412.4] 330.2±25.5 [310.5 385.3] wakefulness after sleep onset (waso, min.) 39.7±25.6 [10.2 78.5] 68.7±42.2 [11.5 143.1] 43.8±25.2 [5.6 73.9] 75.7±57.7* [6.5 189.2] subjective measure of sleep time in bed (tib, min.) 422.4±20.3 [390.3 -480.6] 420.1±15.6 [385.6 453.2] 421.6±16.5 [390.7 460.7] 419.7±19.1 [385.6 460.7] total sleep time (tst, min.) 395.2±28.2 [360.0 -450.3] 380.6±22.2 [350.6 448.6] 380.0±33.4 [344.7 440.3] 374.6±18.4 [330.8 428.2] sleep-onset latency (sol, min.) 15.7±6.4 [3.8 25.0] 26.0±22.2 [5.0 90.0] 32.0±23.1 [5.0 100.0] 25.0±14.8 [5.0 55.2] number of awakenings 1.5±1.0 [0.0 2.8] 2.2±1.6 [0.0 5.0] 2.1±1.3 [0.0 5.0] 3.0±2.0‡ [0.0 6.0] wakefulness after sleep onset (waso, min.) 11.3±11.5 [3.8 38.8] 14.3±18.2 [4.2 60.0] 9.6±13.7 [2.0 73.9] 20.7±28.2 [1.8 90.0] sleep efficiency (se) (%) 93.6±6.4 [90.1 97.6] 90.5±6.9 [88.3 96.4] 90.0±6.7 [88.4 95.3] 89.0±9.2 [83.2 93.1] sleep quality (sq) (0 100 mm, vas) 56.8±9.5 [41.5 70.8] 58.7±15.8 [29.0 74.2] 62.2±12.9 [46.3 78.4] 53.0±12.9 [39.1 69.4] subjective measure of muscular pain intensity of pain (0 100 mm, vas) 3.9±4.9 15.6±21.9 13.8±12.6 7.1±8.6 subjective measure of mood calm-anxious scale (0 100 mm, vas) 24.5±13.3 34.1±19.2 36.4±15.7 35.0±13.2 tired-energetic scale (0 100 mm, vas) 47.9±16.3 25.2±16.9† 21.9±15.3† 23.6±16.4† data presented as mean ± sd, n=10. data in [ ] – range. *p<0.05 versus pre-exercise. † p<0.01 versus pre-exercise. ‡ p<0.001 versus pre-exercise. sajsm vol 23 no. 1 2011 7 waso). as seen in table ii, on the third night of cycling, more of the riders recorded an increase in their time waso (objective), more of the riders experienced an increase in their number of awakenings during the night and an increase in their subjective waso, and the se and sq decreased in more of the riders. even though their sleep was unaffected on the first and second nights of mountain biking, the mountain bikers felt more tired, compared with the pre-exercise stage, as assessed by the vas, on each of the three mountain biking nights. the changes in the mountain bikers’ sleep on the third night of exercise were not as a result of muscular pain, nor a change in the level of anxiety, since there was no difference in the riders’ pain or mood between the pre-exercise stage and the three nights of mountain biking. in our study, the exclusion of pain and anxiety as extraneous factors influencing sleep was an important finding since concomitant depression, pain and anxiety can have a negative impact on sq 19,20 and would have confounded the findings. our study is the first to assess the effect of repeated endurance exercise on subjective and objective measures of sleep. previous studies have investigated the effect of one day of endurance exercise on objective measures of sleep. trained marathon runners experienced no difference in their sleep after they rested, ran a 15 km race or a 42.2 km race. 5 however, after the same subjects participated in an ultra-triathlon, which lasted up to 12 hours, the amount of rapid eye movement (rem) sleep was reduced, rem onset was delayed and waso was increased by up to 40%. 5 in our study, the sleep of the mountain bikers was not affected on the first or second night of the mountain biking, but may have been affected if they had ridden for longer each day or if they had ridden at a higher intensity. the mountain bikers were asked to ride at a similar sub-maximal intensity on each day of riding and they rated their perceived exertion as 5 on the 10-point borg scale on each day. we were therefore not able to assess the effect of increased riding intensity on sq. in our study, the repeated four and a half hours of sub-maximal-intensity mountain biking may have resulted in sleep disruption by the third night as a result of a cumulative effect of the exercise. indeed, the proposal of a threshold of intensity and duration of exercise by driver et al. 5 seems to apply to the mountain bikers in our study; they may have reached their threshold only by the third day of exercise. a possible factor to explain the sleep disruption after three days of riding, although not measured in our study, is that of circulating cytokines. 4,21,22 during exercise cytokines, such as interleukin-1 (il-1), interleukin-6 (il-6) and tumour necrosis factor-α (tnf-α), which also play a role in regulating sleep, increase. 4 il-1 and tnf-α regulate sleep by controlling body temperature 4 and higher concentrations of il-6 and tnf-α have been found in people who have sleep disorders associated with increased wakefulness. 4 in our study, high concentrations of il-6 may explain the increased wakefulness observed in the mountain bikers on the night of the third day of exercise. further research would be needed to investigate the effects of repeated mountain biking over more than three days as well as a higher intensity of exercise. top international competitive events require mountain bikers to ride for seven or more days, sometimes for more than six hours per day. it would be interesting to determine the effect of this mountain biking on a cyclist’s sleep over each day and to measure their pain, mood, body temperature, cytokine profile and cycling performance over the days. in addition, the role of sleeping in an unfamiliar environment after cycling should also be considered to obtain a more complete picture of the endurance cycling event. in our study we have shown that three days of repeated endurance sub-maximal exercise do have a negative effect on the sleep of the mountain bikers, but more research needs to be carried out to determine the exact mechanisms of these effects and also to determine the impact that these changes in sleep may have on the safety and performance of the mountain bikers. acknowledgements we would like to thank the wits dial-a-bed sleep laboratory and the university of the witwatersrand’s brain function research group for funding. references 1. driver hs, taylor sr. exercise and sleep. sleep med rev 2000;4:387402. 2. youngstedt sd. effects of exercise on sleep. clin sports med 2005;24:355365. table ii. number of subjects (out of total of 10 subjects) who showed an increase (↑), decrease (↓) or no change (↔) in their measures of sleep, compared with baseline, on each night after cycling (data are shown as the number of subjects/total number of 10 subjects) night 1 night 2 night 3 objective measure of sleep wakefulness after sleep onset (waso, min.) 7/10 ↑ 2/10 ↓ 1/10 ↔ 5/10 ↑ 4/10 ↓ 1/10 ↔ 8/10 ↑ 1/10 ↓ 1/10 ↔ subjective measure of sleep sleep-onset latency (sol, min.) 5/10 ↑ 5/10 ↓ 5/10 ↑ 5/10 ↓ 5/10 ↑ 5/10 ↓ number of awakenings 4/10 ↑ 2/10 ↓ 4/10 ↔ 4/10 ↑ 1/10 ↓ 5/10 ↔ 7/10 ↑ 1/10 ↓ 2/10 ↔ wakefulness after sleep onset (waso, min.) 4/10 ↑ 3/10 ↓ 3/10 ↔ 4/10 ↑ 4/10 ↓ 2/10 ↔ 6/10 ↑ 2/10 ↓ 2/10 ↔ sleep efficiency (se) (%) 3/10 ↑ 4/10 ↓ 3/10 ↔ 2/10 ↑ 3/10 ↓ 5/10 ↔ 1/10 ↑ 6/10 ↓ 3/10 ↔ sleep quality (sq) (0 100 mm, vas) 5/10 ↑ 3/10 ↓ 2/10 ↔ 5/10 ↑ 4/10 ↓ 1/10 ↔ 1/10 ↑ 6/10 ↓3/10 ↔ 3/10 ↔ 8 sajsm vol 23 no. 1 2011 3. singh na, clements km, fiatarone ma. a randomized controlled trial of the effect of exercise on sleep. sleep 1997;20:95-101. 4. santos rv, tufik s, de mello mt. exercise, sleep and cytokines: is there a relation? sleep med rev 2007;11:231-239. 5. driver hs, rogers gg, mitchell d, et al. prolonged endurance exercise and sleep disruption. med sci sports exerc 1994;26:903-907. 6. youngstedt sd, kripke df, elliott ja. is sleep disturbed by vigorous latenight exercise? med sci sports exerc 1991;31:864-869. 7. whaley mh, brubaker ph, otto rm. acsm’s guidelines for exercise testing and prescription. 7th ed. philadelphia: lippincott williams and wilkins, 2005:349. 8. miwa h, sasahara s, matsui t. roll-over detection and sleep quality measurement using a wearable sensor. conf proc ieee eng med biol soc 2007:1507-1510. 9. polman r, nicholls ar, cohen j, et al. the influence of game location and outcome on behaviour and mood states among professional rugby league players. j sports sci 2007;25:1491-1500. 10. gonzales-alonso j, teller c, andersen sl, et al. influence of body temperature on the development of fatigue during prolonged exercise in the heat. j appl physiol 1999;86:1032-1039. 11. youngstedt sd. effects of exercise on sleep. clin sports med 2005;24:355365. 12. o’connor pj, breus mj, youngstedt sd. exercise-induced increase in core body temperature does not disrupt behavioural measures of sleep. physiol behav 1998;64:213-217. 13. landis ca, frey ca, lentz mj, et al. self-reported sleep quality and fatigue correlates with actigraphy in midlife women with fibromyalgia. nurs res 2003;52:140-147. 14. bruni o, russo pm, violani c, et al. sleep and migraine: an actigraphy study. cephalgia 2004;24:134-139. 15. perlis ml, giles de. psychophysiological insomnia: the behavioural model and a neurocognitive perspective. j sleep res 1997;6:179-188. 16. baker fc, driver hs. self-reported sleep across the menstrual cycle in young, healthy women. j psychosom res 2004;56:239-243. 17. chervin rd, guilleminault c. overestimation of sleep latency by patients with suspected hypersomnolence. sleep 1996;19:94-100. 18. baker fc, maloney s, driver hs. a comparison of subjective estimates of sleep with objective polysomnographic data in healthy men and women. j psychosom res 1999;47:335-341. 19. lavigne gj, mcmillan d, zucconi m. pain and sleep in: kryger mh, roth t, dement wc, eds. principles and practice of sleep medicine. 3rd ed. philadelphia: elsevier saunders, 2005:1246-1255. 20. ohayon mm. chronic pain and sleep. int j sleep disorders 2006;1:1621. 21. haahr pm, pedersen bk, fomsgaard a, et al. effect of physical exercise on in vitro production of interleukin 1, interleukin 6, tumour necrosis factor-alpha, interleukin 2 and interferon-gamma. int j sports med 1991;12:223-227. 22. moldoveanu ai, shephard rj, shek pn. the cytokine response to physical activity and training. sports med 2001;31:115-144. introduction the lack of agreement between subjective and objective measures of intensity led borg to develop the ratings of perceived exertion (rpe) scale. 1 perceived exertion has been widely used as a subjective measure of aerobic exercise intensity. while correlating well with objective physiological measures such as heart rate (hr) 1-4 and vo2, 1-3 it is generally agreed that perceptual responses are attributed to numerous physiological and psychological variables rather than any a single mediator. 4-6 rpe is supported by the american college of sports medicine as a convenient and practical method for quantifying intensity in aerobic-type exercise. 7 the application of rpe has recently been extended to exercise modalities dominated by oxygenindependent metabolic pathways such as resistance training (rt), with results suggesting it is a valid measure of effort. 8-10 rt studies show that acute rpe systematically increases with percentage of 1 repetition maximum (1rm) lifted when exercise is terminated at a predetermined number of repetitions (reps). 9,11-13 for example, sweet et al. 10 observed this trend as the percentage of 1rm increased from 50% to 70% to 90%, despite a decreased number of repetitions (15, 10 and 4 respectively). while original work dealt with rpe during an exercise bout, foster et al. 14,15 developed the concept of session rpe. this rpe paradigm relative to the entire workout is estimated in the postexercise period and is not associated with any specific time point in the bout. this permits a subjective estimation for an entire training session. session rpe has been used to quantify rt sessions. a study comparing session rpe across 3 different workouts involving 5 exercises (1 set each) at 50% (15 reps), 70% (10 reps), and 90% (5 reps) of 1-rm, 8 found session rpe to be reliable for quantifying intensity during rt and concluded that session rpe values increased concurrently with percentage of 1rm. however, participants only completed one set and stopped upon completing the predetermined number of repetitions, and therefore total work between varying intensities was not equated. sweet et al. 10 made similar conclusions; however, previous studies identified an association between perceptual measures and intensity, with minimal consideration for effects of total work, for each set of exercise or for the entire bout. original research article acute and session rpe responses during resistance training: bouts to failure at 60% and 90% of 1rm abstract objective. to compare resistance bouts performed to failure at low (60% 1rm) and high (90% 1rm) workloads for acute rate of perceived exertion (rpe) (per exercise), session rpe (s-rpe) (30 min post), hr (per exercise) and total work (per session, and per exercise). background. rpe is a convenient method for quantifying intensity in aerobic exercise. however, rpe has recently been extended to exercise modalities dominated by anaerobic pathways such as resistance training (rt). method. subjects (n=12) were assessed using an exercise-specific 1 repetition maximum (1rm) for 6 exercises. on separate days in a counterbalanced order, subjects performed 3 sets of each exercise to volitional failure at a low intensity (li) and a high intensity (hi) with 2 minutes rest between sets and exercises. at the end of each set, subjects estimated acute rpe for that set using a 10-point numerical scale. thirty minutes after the end of the exercise session subjects estimated their s-rpe for the entire workout. hr, total work, and acute rpe were compared (hi v. li) using repeated measures anova. results. a paired samples t-test showed li was significantly higher (p=0.039) than hi for session rpe (li=8.8±0.8, hi=6.3±1.2) and total work (li=17461±4419, hi=8659±2256) (p=0.043). per exercise, total work and acute rpe were significantly greater (p=0.01) for li for all exercises. peak hr was significantly higher per exercise during li for leg press (p=0.041), bench press (p=0.031), lat pull-down (p=0.037) and shoulder press (p=0.046). correspondence: r c pritchett department health human performance and nutrition 400 east university way central washington university ellensburg wa, 98926 tel : 509-963-1338 fax : 509-963-1848 e-mail: pritcher@cwu.edu robert c pritchett (phd)1 james m green (phd, facsm)2 phillip j wickwire (phd)3 kelly l pritchett (phd, rd)1 mark s kovacs (phd)4 1 department of health, human performance and nutrition, central washington university, ellensburg 2 department of health, physical education and recreation, the university of north alabama, florence 3 department of health, physical education and sports science, kennesaw state university, kennesaw 4 department of health, physical education, and recreation, jacksonville state university, jacksonville conclusion. in resistance exercise performed to failure, total work influences acute and session rpe more so than percentage 1rm. sajsm vol 21 no. 1 2009 23 previous studies indicate that acute rpe increases concomitantly with intensity (i.e. percentage of 1-rm) 8-10 electromyography activity, and blood lactate. 12 however, a greater rpe might result from the knowledge that the resistance is greater, which could be independent of the exercise-associated fatigue and pain to which rpe is typically attributed. this could disrupt correspondence between physiological overload and a subjective rating that might be particularly problematic when exercise is terminated prior to volitional exhaustion, a common end-point in rt. the lack of substantial research taking individuals to volitional exhaustion during rt magnifies the belief that perceptual responses to exhaustive rt are not well understood. therefore the purpose of this study was to investigate acute and session rpe between hi (90% 1rm) and li (60% 1rm) rt sessions when subjects were required to perform repetitions to volitional failure. methods subjects twelve recreationally strength trained (minimum 6 weeks) males served as participants. prior to data collection, subjects completed and signed a written informed consent outlining requirements for participation. all procedures were approved by the university review board for protection of human subjects. each subject was given instructions to arrive for testing well hydrated, at least 3 hours postprandial, and having abstained from caffeine and alcohol for a minimum of 24 hours. age (years), height (cm) (medart: st louis, mo) and mass (kg) (detecto-medic: detecto scales inc. brooklyn, ny usa) were measured and body fat percentage was estimated using lange skinfold calipers (cambridge, md, usa) and a three-site method (chest, abdomen, and thigh). 16 design each subject completed a hi (90% of 1rm) and a li trial (60% of 1rm) performed in a counterbalanced order, between the 2 intensity trials. subjects were first assessed for their 1rm and then on separate days were called back to perform the hi and li trials. each session include 3 sets of 6 exercises performed to volitional fatigue. exercises were performed in a specific order: leg press, bench press, lat pull down, shoulder press, triceps press, and biceps curl. 1rm determination following descriptive data, each participant completed a 1rm for all exercises in the order mentioned previously. all exercises were performed on cybex weight equipment (lumax, ronkonkoma, ny). each 1 rm was defined as the heaviest weight that could be lifted for 1 complete repetition. 17,18 each subject performed three sets of each exercise at sub-maximal resistance with stepwise increases (based on participant feedback) in resistance until the participant could perform the lift for only 1 repetition. in order to enhance recovery, 2 3 minutes between attempts and 5 minutes between exercises was provided. 19 low-intensity trial – 60% 1rm subjects completed a warm-up prior to the first lower body exercise (leg press) and the first upper body exercise (bench press) consisting of 8 reps at 30% of 1rm. following the warm-up set, each subject performed 3 sets to failure at 60% of 1rm for each exercise. the inability to complete a full repetition was considered ‘failure’. resistance for each exercise was set to the weight corresponding to the appropriate percentage of each individual 1rm (within 0.5 kg). the orders of the exercises were kept the same throughout the exercise regimen. subjects were asked to estimate their acute rpe within 10 seconds of completing each set, utilising a category ratio (cr) 10point rpe scale specific to strength training. 4 subjects were held to a 2-minute recovery between sets and 2 minutes between exercises throughout the work-out session. subjects were asked to sit quietly for the next 30 minutes. acute rpe was recorded upon completion of each set. session rpe was also recorded 30 minutes after each session. peak hr for each set (highest hr response observed) was recorded, using a polar hr monitor (stamford, ct, usa). thirty minutes following each exercise session subjects estimated their session rpe relative to the entire work-out session using the same scale by answering the question ‘how do you rate the entire workout?’. 15 session rpe was recorded following the 30-minute period to prevent the perceptual feelings at the immediate termination of exercise from dominating this measure as it is intended to reflect feelings for the entire bout. 15 high-intensity trial – 90% of 1rm the hi trial was conducted in the same manner as the li trial except that resistance was set at 90% of 1rm. statistical analysis hi and li were compared using a 2 (trials) x 3 (sets) repeated measures anova for each variable (reps, acute rpe, and hr) within each exercise. rpe per exercise was calculated using the average of three sets. total work for the exercise session was calculated by adding the sum of each exercise. a bonferroni post-hoc procedure was applied to locate differences when anova revealed a significant interaction. session rpe and total work (li v. hi) were compared using a paired samples t-test. statistical significance was set at p<0.05. a pearson’s product – moment coefficient of correlation was used for both session rpe and volume (hi and li). all data are reported as means ± standard deviations. results means and standard deviations for descriptive data were: age (23.8± 3.1 yrs), mass (78.8±14.5 kg), height (175.1±5.6 cm), body fat (13.1±6.6 %). fig. 1a shows li was significantly higher (p=0.039) for session rpe (8.8±0.8) compared with hi (6.3±1.2). fig. 1b shows total work for the entire session was also significantly higher (p=0.043) for li (17 461±4 419) compared with hi (8 658±2 255). total work per exercise for li (fig. 2) was significantly higher (p=0.021) than for hi. peak hr for triceps press and biceps curl was not significantly different li v. hi (p=0.075). peak hr (fig. 3) was however significantly higher during li for leg press (p=0.041), bench press (p=0.031), lat pulldown (p=0.037) and shoulder press (p=0.046) respectively. fig. 4 depicts acute rpe, which was significantly higher (p=0.029) for li v. hi per each exercise. a strong relationship between total work and session rpe is depicted in fig. 5, which is evident by the positive correlation for both li and hi (r 2 =0.85, p=0.029). discussion rpe is a convenient method for quantifying training effort. typically, subjects perceive exercise to be more strenuous with an increase in intensity. 8,11 however, few studies have assessed subjective measures when resistance training bouts are completed to failure. this study compared acute and session rpe (s-rpe) throughout an entire resistance training exercise session when participants completed 3 sets of 6 exercises at low and high intensities to volitional failure. 24 sajsm vol 21 no. 1 2009 s-rpe responses results indicate that at a li trial (60% 1rm) s-rpe was greater compared with the hi trial (fig. 1a). this may be attributed to the significantly (p=0.043) greater total work for the li exercise session (fig. 1b). furthermore, this suggests that s-rpe within the current paradigm (multiple sets to volitional exhaustion) is affected by the total work of an entire exercise bout more so than the intensity (resistance) of the bout. this supports recent work by sigh et al., 20 but it is contrary to prior research reporting acute rpe is primarily influenced by exercise intensity, 8,10,11 and not total work being performed. previous studies, utilised rt sets at sub-maximal intensities, and have terminated the exercise protocol prior to subjects’ volitional failure. 8 results from these particular studies have reported mean rpe values taken throughout the exercise bout correspond well with the srpe. consequently, authors concluded that s-rpe is a valid method of quantifying entire bouts of resistance training. 8 day et al. 8 differentiated between high (90% of 1rm 4 5 reps), moderate (70% of 1rm 10 reps) and low (50% of 1rm 15 reps) with subjects completing only 1 set. rpe was higher for the hi bout, where subjects were asked to complete a maximum of 5 repetitions. some subjects reached volitional failure upon completion of the fourth repetition whereas the moderate and li bouts prompted none of the subjects to failure. 8 the experimental protocol used by day et al. 8 was such that the training intensities and corresponding repetitions allowed for variation in the total amount of work performed between testing sessions. however, the unique aspect of the current study is that subjects exercised to volitional exhaustion at both hi and li intensities. american college of sports medicine guidelines for resistance exercise prescription state that ‘high intensity can be achieved either by performing a few repetitions (e.g. 3 6) with heavy resistance or by several repetitions (e.g. 8 12) with a lighter resistance’. 7 because of the significantly (p=0.043) greater total work (achieved via higher repetitions) during the li trials, it is plausible that subjects in the current study achieved greater disruption to their internal physiological environment which may have contributed to elevated rpes. because of the amount of total work in li trial, s-rpe was significantly higher. also, li generated a significantly (p=0.041) higher peak hr, but only for the first 4 exercises with peak hr response 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 leg press bench press lat pull down shoulder press triceps press biceps press low int. high int. * * * * * *      fig. 2. total work (weight x reps) for each exercises li v. hi. li was significantly higher than hi (*p< 0.021). values are means and sd; n=12. fig. 3. peak hr for individual exercises li v. hi. peak hr was significantly higher during li for leg press (*p< 0.041), bench press (p=0.031), lat pull-down (p=0.037) and shoulder press (p=0.046). values are means and sd; n=12. 0 20 40 60 80 100 120 140 160 180 leg press bench press lat pull down shoulder press triceps press biceps press b .m in -1 low int high int * * * * 0 5000 10000 15000 20000 25000 low intensity high intensity t o ta l w o rk * 0 2 4 6 8 10 s es si o n r p e * b fig. 1 a and b. session rpe values, 30 min post-exercise bout (*p<0.039) (b). total work (weight x reps) for entire exercise bout * li v. hi. (p<0.043). each exercise bout consisted of 6 exercises: leg press, bench press, lat pull-down, shoulder press, triceps press, and biceps curl. values are means and sd; n=12. a 0 1 2 3 4 5 6 7 8 9 10 leg press bench press lat pull down shoulder press triceps press biceps press a ct u te r p e low int high int. * * * * * * fig. 4. acute rpe for individual exercises. rpe was significantly higher (*p< 0.029) for li v. hi. values are means and sd; n=12. y = 2120.4x 4453.3 r² = 0.8456 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 4 5 6 7 8 9 10 t o ta lw o rk session rpe fig. 5. correlation between total work and s-rpe for both li and hi. total work and s-rpe positive linear relationship (r 2 =0.85, p=0.029). sajsm vol 21 no. 1 2009 25 converging (between li and hi) in the latter bouts. even with a strong link between rpe and hr 14,15,21 in the current study, there was a stronger association between session rpe and total volume (r 2 = 0.85) (fig. 5). lagally et al. 9 found electromyographic (emg) activity increased significantly as the intensity of exercise increased from 30% to 90% 1rm. furthermore, post-exercise blood lactate was significantly greater at 90% 1-rm than 30% 1-rm. greater rpe at 90%1rm between trials in which total volume was equated led lagally 9 to conclude that rpe is coupled with intensity more tightly than with volume. conversely, current results indicate rpe is more closely linked with work than %1rm as higher acute and session rpe were found with lower intensity bouts in which a greater volume was completed. because the principal difference between studies (current study and lagally 12 ) is termination of exercise at a predetermined number of reps 12 and volitional failure (current study), it could be concluded that the factor dominating rpe is dependent on the rt end-point. an additional possibility exists regarding perceptual measures. according to lagally et al. 9 and gearhart et al. 11 it is possible that participants were immediately capable of detecting the considerable resistance variation between trials. greater rpe estimations could have been based on perceptions of resistance rather than physiological changes and associated feelings of fatigue. continuing to volitional exhaustion in the current study helped to ensure subjects were fatigued as indicated by failure to complete an additional repetition even when verbally encouraged. it is therefore proposed that session rpe for li was greater due to the cumulative fatigue associated with a greater amount of total volume performed. this again suggests that when rt exercises are completed to volitional failure, associated perceptual measures are more sensitive to total work than to resistance. acute rpe and hr responses the peak hr responses for each exercise, was significantly (p<0.05) higher for li for leg press, bench press and lat pull-down and shoulder press. however, for triceps press and biceps curl there was no significant difference in hr response. this may be related to the short recovery time (2 minutes) between exercises, and the cumulative effects of physiological fatigue that presumably increased concurrently as total work volume diverged (li v. hi) with each exercise set. during li, the greater volume (per set, per exercise) may have resulted in a greater disruption of the internal environment (as speculated earlier) and consequently successive sets may have been initiated with less relative recovery (v. hi). viewing acute rpe estimations concurrently with peak hr responses, and differences in work volume per exercise, leads to similar conclusions for acute rpe as for s-rpe. that is, when sets are completed to volitional failure, total volume weighs more heavily on perceptual responses than does percentage 1rm. practical application s-rpe is responsive to multiple factors, many of which have yet to be clearly defined. the current study indicates that the volume of work is an important determinant in strength training when comparing repeated bouts of lighter and heavier resistances completed to failure. while further investigation is warranted, it is plausible that srpe would provide an effective gauge of overall difficulty of a given training session with potential for also identifying overtraining. conclusion s-rpe is shown to be affected by total work rather than just exercise intensity alone (% 1rm). these results extend the knowledge regarding perceived exertion during resistance training. more specifically, when using rpe to quantify resistance training the amount of total work must be taken into consideration when bouts are completed to failure. this suggests that s-rpe is a valuable quantification tool of work performed throughout the exercise bout in that paradigm. in consideration of the current study and previous research, rpe relationship with %1rm and total work seems to be dependent on the end-point of the exercise bout with a stronger relationship with total work, than exercise intensity during exhaustive bouts. subsequently s-rpe may be considered a safe and reliable method for monitoring strength training gains and a valid tool for monitoring training programmes, which would offer a quick and subjective method of quantifying rt exercise bouts. references 1. borg g. perceived exertion as an indicator of somatic stress. scan j rehab med 1970;2:92-98. 2. borg g. perceived exertion: a note on “history” and methods. med sci sports exerc 1973;2:99-93. 3. noble bj. clinical application of perceived exertion. med sci sports exerc 1982;14:406-411. 4. noble bj, borg g, jacobs i, ceci r, kaiser p. a category-ratio perceived exertion scale: relationship to blood and muscle lactates and heart rate. med sci sports exerc 1982;15:523-528. 5. mihevic p. sensory cues for perceived exertion: a review. med sci sports exerc 1981;13:150-156. 6. robertson rj. central signals of perceived exertion during exercise. med sci sports exerc 1982;14:390-396. 7. american college of sports medicine. guidelines for exercise testing and prescription, 7th ed. philadelphia, pa: lippincott williams and wilkins; 2005. 8. day ml, mcguigan r, brice g, foster c. monitoring exercise intensity during resistance training using the session rpe scale. j strength cond res 2004;18:353-358. 9. lagally km, mc caw st, young gt, medema hc, thomas dq. ratings of perceived exertion and muscle activity during the bench press exercise in recreational and novice lifters. j strength cond res 2004;18:359-364. 10. sweet tw, foster c, mcguigan mr, brice g. quantition of resistance training using the session rating of perceived exertion method. j strength cond res 2004;18:796-802. 11. gearhart rfjr, goss fl, lagally km, et al. ratings of perceived exertion in active muscle during high-intensity and low-intensity resistance exercise. j strength cond res 2002;16:87-91. 12. lagally km, robertson rj, gallagher r. gearhart r, gross fl. ratings of perceived exertion during low and high-intensity resistance exercise by young adults. percp motor skills 2002;94:723-731. 13. suminski rr, robertson rj, arslanian s, et al. perception of effort during resistance exercise. j strength cond res 1997;11:261-265. 14. foster c, daines e, hector l, snyder a, welsh r. athletic performance in relation to training load. wisc med j 1996;95:370-374. 15. foster c, daines d, florhaug j, et al. new approach to monitoring exercise training. j strength cond res 2001;16:109-115. 16. pollock ml, schmidt dh, jackson as. measurment of cardiorespiratory fitness and body composition in the clinical setting. clinical therapy 1980;6:12-27. 17. fleck s. periodization strength training: a critical review. j strength cond res 1999;13:82-89. 18. kraemer wj, dziados je, marchitelli lj, et al. effects of different heavyresistance exercises protocols on b-endorphin concentrations. j appl physiol 1993;74:450-459. 19. wade g. tests and measurments. meeting the standards of professional football. nsca j 1982;4(3):23. 20. singh f, foster c, david t, mcguigan m. monitoring different types of resistance training using session rating of perceived exertion. int j sports physiol performance 2007;2:34-45. 21. skinner j, hustler r, bersteinova v, buskirk e. perception of effort during different types of exercise and under different environmental conditions. med sci sports exerc 1973;5:110-115. 26 sajsm vol 21 no. 1 2009 original research 12 sajsm vol. 25 no. 1 2013 background. shoulder injuries are the most severe injuries in rugby union players, accounting for almost 20% of injuries related to the sport and resulting in lost playing hours. objective. to profile the thoracic posture, scapular muscle activation patterns and rotator cuff muscle isokinetic strength of semi-professional rugby union players. methods. using the hand-behind-the-neck and -back methods, we manually tested the range of motion (rom) of the shoulder joints of 91 uninjured semi-professional rugby union players who consented to participate in the study. profiling and classification of thoracic posture was performed according to the new york posture test. activation patterns of the upper and lower trapezius, serratus anterior and infraspinatus scapular muscles were determined by electromyography. the isokinetic muscle strength of the rotator cuff muscles was determined at 60°/sec by measuring the concentric and eccentric forces during internal rotation (ir) and external rotation (er). results. participants presented with non-ideal or unsatisfactory internal (59%) and external (85%) rotators of the shoulder. a slightly abnormal or abnormal forward head posture was observed in 55% of participants, while 68% had an abnormal shoulder position in the lateral view. the muscle activation sequence of the rotator cuff muscles was: (i) serratus anterior, (ii) lower trapezius, (iii) infraspinatus, and (iv) upper trapezius. the isokinetic er/ir muscle-strength ratio during concentric muscle contraction was 64% (standard deviation (sd) ±14) for the left shoulder and 54% (sd ±10) for the right shoulder. the er/ir ratio for eccentric muscle contraction was 67% (sd ±12) and 61% (sd ±9) for the left and right shoulders, respectively. conclusions. non-ideal or unsatisfactory flexibility of the external rotators of the shoulder, a forward shoulder posture in the lateral view, and weakness of the external rotators did not result in an abnormal rotator cuff muscle activation pattern in this study. postural deviations may, however, increase the risk of shoulder injury in rugby union players in the long term, and should be corrected. s afr j sm 2013;25(1):12-17. doi:10.7196/sajsm.366 thoracic posture, shoulder muscle activation patterns and isokinetic strength of semi-professional rugby union players g bolton, s j moss, m sparks, p c venter physical activity, sport and recreation, faculty of health sciences, north-west university, potchefstroom, south africa g bolton, msc s j moss, phd, mba m sparks, msc p c venter, mb chb, mmed corresponding author: s j moss (hanlie.moss@nwu.ac.za) poor posture, scapular dyskinesia, altered scapular muscle recruitment patterns and shoulder-strength weaknesses or imbalances may be associated with shoulder injuries in athletes;[1] however, this has not been proven conclusively for rugby players. despite the fact that rugby union enjoys increasing worldwide popularity, it has one of the highest reported incidences of injury.[2] the shoulder is the second most common site of injury in the rugby union player, accounting for almost 20% of injuries related to the sport.[3] despite correlations between rounded shoulders, severe kyphosis and forward head posture with inter-scapula pain among the general population,[4] similar findings are limited with regard to rugby union players. there have been reports, however, of a relationship between postural deviation and incorrect shoulder kinematics.[5] knowledge of the patterns of shoulder muscle timing and the functional capabilities of the scapular rotators is vitally important to understanding the behaviour of the joint system, particularly under demanding circumstances such as participation in sport.[6,7] scapulothoracic dysfunction is often seen in patients with shoulder problems.[1,8] among swimmers with shoulder injuries, there is significantly increased variability in the timing of activation in the upper and lower part of the trapezius muscle,[1] reflecting inconsistent or poorly co-ordinated muscle activation.[1] with regard to rugby players, in a study to define muscle-activation patterns in selected shoulder girdle muscles during a front-on tackle in asymptomatic subjects,[9] a consistently earlier activation of the serratus anterior muscle was observed prior to impact, compared with the pectoralis major, biceps brachii, latissimus dorsi and infraspinatus.[9] a combination of electromyography (emg) and isokinetic dynamometry could provide information regarding the function of shoulder musculature in sport.[6] it has been suggested that the functional strength of the rotator cuff muscles and the rotator-strength ratio are significant predictors of the likelihood of shoulder injury. mailto:hanlie.moss@nwu.ac.za sajsm vol. 25 no. 1 2013 13 the unilateral muscle ratio – the antagonist/agonist muscle-strength ratio of the infraspinatus and teres minor muscles v. the subscapularis and supraspinatus muscles on the ipsilateral side – is also believed to be important in isokinetic testing.[10] a sufficient balance between agonist and antagonist muscle groups apparently provides dynamic stabilisation to the shoulder joint.[10] to provide optimal muscle balance and functional capability for overhead athletes, the strength of the external rotators of the glenohumeral joint should be 65 75% of that of the internal rotator muscles.[10] muscle-strength ratios that lie outside the proposed normative ranges may increase the risk of injury to athletes.[11] furthermore, there is evidence that rugby union players, especially forwards, display poor antagonist/agonist muscle-strength ratios with regard to their shoulder rotator muscles.[12] previous research has indicated a possible association between posture, isokinetic strength, scapular muscle recruitment patterns and injury among the general population and overhead athletes.[1] however, there are few available profiles of rugby union players with regard to the aforementioned factors and the possible associations thereof with injury. the compilation of such profiles for uninjured players could, in theory, assist in the identification of rugby union players who are more likely to be at risk of future injury to the shoulder area. the aim of our study was, therefore, to profile rugby union players accordingly, to assist in the identification of possible musculoskeletal weaknesses. here we report on part of a larger study into the occurrence of shoulder injuries during the 2010 rugby union season at north-west university (nwu)-puk rugby institute. the shoulder is the most injured body region in backline players at the institute. previous work has implicated certain biomechanical and postural aspects, such as tight shoulder internal rotators and adductors, high body mass and kyphosis, as possible intrinsic risk factors for these shoulder injuries; however, the practical significance of these correlations was limited by small sample sizes. we subsequently performed a descriptive study to profile the thoracic posture, scapular muscle activation patterns and rotator cuff muscle isokinetic strength of right-hand-dominant semiprofessional rugby union players. methods participants ninety-five uninjured male rugby union players aged 17 31 years were recruited for the study. all participants were puk u19 a/b, puk u21 a/b (nwu-puk rugby institute) or leopards rugby union senior players (provincial) based in the north west province. all participants gave informed consent to participate in the study following an explanation of the test procedure and study protocols. the ethics committee of nwu approved the study (nwu-0004811a1). all participants were tested in the pre-season to ensure that they were uninjured during the test phase. left-hand-dominant participants (n=4) were excluded from the analysis. measurements demographic information the stature of each participant was measured to the nearest 0.1 cm with a stadiometer (seritex) using the stretch-stature method. body mass was measured to the nearest 0.1 kg with an electronic weighing scale (micro). participants completed an information sheet surveying age, position of play, dominant side and previous injuries. shoulder range of motion biomechanical tests were performed according to a pro forma protocol compiled from various sources. shoulder range of motion (rom) was determined by the hand-behind-the-neck and -back tests. during both tests, participants stood in an upright position. in the hand-behind-the-neck test, participants were instructed to reach over their ipsilateral shoulder with one hand and place it as far down the spinal column as possible. the end-point of movement was marked (representing the most inferior point) with the shoulder in a position of external rotation (er). using the same technique, the contra-lateral hand was placed as far down the spinal column as possible, and the end-point was marked. the distance between the two marks was measured. the players were classified in terms of the discrepancies between the leftand right-shoulder roms: a difference <1 cm was classified as ideal, differences of 1 3 cm were classified as non-ideal, and differences >3 cm were classified as unsatisfactory. during the hand-behind-the-back test, the same principles were applied; however, participants were instructed to place their hands as high as possible on the spinal column (representing the most superior point), with the shoulder in a position of internal rotation (ir). thoracic posture the new york posture test, designed for identifying 13 categories of deformities,[13] was used for the evaluation and identification of possible postural deformities in the participants. assessments were performed by capturing high-quality digital photographs of the lateral and posterior view of each participant. the camera was placed at a 90° angle to the shoulders to ensure accurate calculation of angles. the photographs were analysed with dartfish software (version 4.06.0; dartfish, switzerland). a score of 5 (normal posture), 3 (slightly abnormal posture/moderate deviation) or 1 (abnormal posture/major deviation) was assigned to forward head, winged scapulae/round shoulders and kyphosis aspects of the postures. uneven shoulders were measured by placing bright-yellow markers, 1 cm in diameter, on the posterior-lateral edges or acromial angles of the left and right acromions. uneven shoulders were defined by the angle formed between the line connecting the inferior edges of the markers and a true horizontal line. to reduce the degree of subjectivity, new york posture test criteria were used to score uneven shoulders as follows: 5 (0 2°); 3 (2.1 4.0°) and 1 (>4°). scapular muscle activation patterns emg activities of the scapulothoracic muscles were registered by means of bilateral and simultaneous abduction of both arms in the scapular plane (30° in front of the coronal plane).[1] the output of muscle activation was measured in microvolts (mv). the firing sequence of the muscles was determined by measuring latency times (ms). consequently, the frequency (percentage of times) that a specific muscle group fired in a specific order was calculated. accordingly, the muscles were classified in terms of firing sequence. data were obtained with the myotrace 400 biofeedback system (noraxon usa inc.), which operates by means of a 4-channel transmitter that allows for simultaneous data collection from 4 strategically placed electrodes. emg electrodes were attached unilaterally to the upper and lower trapezius, serratus anterior and infraspinatus muscles, respectively, in accordance with surface electromyography for the non-invasive 14 sajsm vol. 25 no. 1 2013 assessment of muscles (seniam) guidelines.[14] the overlying skin on the muscles was carefully prepared by abrading the outer epidermal layer and removing oil and dirt with alcohol pads. [15] as only 4 channels were available to do the tests, the 4 muscles were measured unilaterally, after which the test was repeated on the contra-lateral side. the participants started the required movement with their arms resting next to their sides. bilateral arm abduction in the scapular plane was performed to a point of 180° of abduction, after which adduction was performed to the original starting point. the test was standardised for both sides by regulating the tempo of abduction and adduction. participants performed the total abduction-adduction sequence in 7 seconds. no resistance was used or applied during the movement. rotator cuff isokinetic muscle strength the torque/peak power and muscle agonist/antagonist ratios of the shoulder were tested with the kin-com 500h isokinetic dynamometer (chattanooga, tennessee) with torque/power expressed in newton meters (nm). torque scores are representative of the moment of force produced by muscle contraction for rotation around a joint.[12] during shoulder ir and er, the participant was seated and strapped to the seat. testing was performed with the arms positioned along the scapular plane, at 90° of abduction and with 90° of elbow flexion. the contralateral arm was held static against the chest throughout the test and the feet were placed on a footrest. the shoulder axis of rotation was aligned with the dynamometer’s axis of rotation. the 2 rotation points were connected with an imaginary line that runs from the dynamometer’s axis of rotation, through the humerus, towards the acromion process. each test started from the point of full er. participants warmed up using the monark 881e rehab trainer (monark, sweden) for 3 min. before the test commenced, each participant was informed about the test procedure. three sub-maximal warm-up repetitions preceded the true test. verbal encouragement was given during the test to ensure maximal torque output. the actual test consisted of a range of 6 concentric and eccentric maximal contractions. the maximal concentric and eccentric torque levels (in nm) of the shoulder-girdle complex were determined at speeds of 60°/sec for ir and er. the above-mentioned values were used to calculate the different isokinetic ratios that were used to evaluate shoulder-muscle performance: the antagonist/agonist ratio and bilateral strength deficit ratio for concentric and eccentric contractions. furthermore, the functional strength ratio was expressed as the eccentric er torque production divided by the concentric ir torque production of a shoulder. this functional ratio appears to be relevant among overhead athletes, due to the fact that an increased activity of the external rotators is required to decelerate the humerus to centre the humeral head during a ballistic action.[16] the dominant and non-dominant shoulders of each participant were measured. statistical analysis spss software (version 17.0; ibm, new york) was used for statistical analyses. descriptive statistics were performed to determine the characteristics of the participants as well as the profiles of the different variables. frequencies and means with standard deviations (sds) were calculated. paired t-tests were performed to determine the differences between the measurements of dominant and non-dominant sides of the same individual. the level of significance was set at p<0.05. results participant characteristics (table 1) indicated that 42% played rugby union as forwards. statistically significant differences were found between forwards and backline players with regard to stature or height, weight, body mass index (bmi) and previous injuries to the shoulder joint. twenty-eight per cent of the participants had suffered previous injuries to the shoulder, including previous surgery, dislocations or subluxations, and any injury that required the player to seek medical attention for intervention. the injuries could have been sustained at any stage, up until the end of the preceding season. rom tests were performed to determine the comparative flexibility of the shoulder internal and external rotators (hand-behind-the-neck and -back tests, respectively) (table 2). sixty-one per cent of the participants displayed non-ideal or unsatisfactory flexibility of their internal rotators when compared bilaterally. with regard to external rotator flexibility, upon bilateral comparison 84% of the participants were classified as non-ideal or unsatisfactory. from the new york posture test[13] used to evaluate thoracic posture (fig. 1), more than half of the participants displayed a slightly abnormal or abnormal forward head position and a normal classification regarding a rounded back. the majority of the participants displayed normal posture with regard to uneven shoulders. notably, 67% of the participants were classified as slightly abnormal or abnormal regarding their forward shoulder position. in terms of the average firing order of muscle activation on the dominant side, the consensus sequence was: (i) serratus anterior, (ii) lower trapezius, (iii) infraspinatus and (iv) upper trapezius (fig. 2; x-axis indicates the firing order, y-axis indicates the frequency of that order). the serratus anterior had the highest frequency for firing first (40%) and the lower trapezius had the highest frequency for firing second (42%). a similar firing order was observed on the table 1. participant characteristics mean (±sd) variable all (n=91) forwards (n=40) backs (n=51) age (years) 20.8 (±2.9) 20.8 (±2.7) 20.7 (±3.0) stature (cm) 182.0 (±8.1) 186.5 (±7.9)* 178.4 (±6.4)* mass (kg) 91.5 (±15.1) 103.3 (±13.3)* 82.2 (±8.6)* previous injury (%) 27.5 40 17.6 bmi (kg/m2) 27.5 (±3.3) 29.7 (±3.5)* 25.8 (±1.7)* sd = standard deviation; bmi = body mass index. *significant difference (p<0.05). table 2. frequency of shoulder flexibility (non-dominant v. dominant) rom test ideal % non-ideal % unsatisfactory % hand-behind-the-neck 39.3 42.7 18.0 hand-behind-the-back 15.7 23.6 60.7 rom = range of motion. sajsm vol. 25 no. 1 2013 15 non-dominant side, despite the fact that different frequencies were observed (fig. 3). the results of testing the isokinetic shoulder strengths with the dynamometer (table 3) were that the antagonist/agonist ratio regarding concentric shoulder rotation of the non-dominant shoulder was slightly lower than what is regarded as acceptable (64%). the corresponding ratio for the dominant shoulder was even lower. a statistically significant difference was observed between the values for the right and left sides. a statistically significant difference was also found between the antagonist/agonist ratio regarding eccentric shoulder rotation of the non-dominant shoulder and the antagonist/ agonist ratio regarding eccentric shoulder rotation of the dominant shoulder. the bilateral deficit during concentric ir indicated that the participants’ non-dominant shoulders were generally stronger than their dominant shoulders during ir. with regard to concentric er, the participants’ shoulders also appeared to be stronger on the nondominant side. the bilateral deficit during eccentric ir shows that this right-dominant group was stronger on the dominant side. when one considers the er component, it seems that there is parity between the average strength of the dominant and non-dominant shoulders. discussion the main objective of this study was to profile semi-professional rugby union players in terms of thoracic posture, scapular muscle activation patterns and rotator cuff isokinetic muscle strength. the results indicated that the majority of the players of the leopards rugby union and nwu-puk rugby institute had less than ideal or unsatisfactory flexibility of their external shoulder rotators when the left and right shoulders were compared. testing the flexibility of the shoulder internal rotators indicated that only a small percentage of the players had ideal flexibility when their left and right shoulders were compared. this supports the findings of a previous study[17] of a diminished glenohumeral rotation range among professional rugby players in comparison with a control group. another study also reported deficiencies in rugby players’ rom, possibly attributed to fig. 1. thoracic postural profile of participants according to the new york posture test.[20] fig. 2. percentage of times that the dominant upper trapezius, lower trapezius, infraspinatus and serratus anterior muscles fired in a specific order during abduction in the scapular plane. fig. 3. percentage of times that the non-dominant upper trapezius, lower trapezius, infraspinatus and serratus anterior muscles fired in a specific order during abduction in the scapular plane. table 3. ir and er isokinetic muscle-strength ratios muscle movement mean (±sd) cnd er/ir 64.14 (±14.41)* cd er/ir 54.55 (±10.18)* end er/ir 67.24 (±11.62)* ed er/ir 61.52 (±9.73)* nd/dcir 90.65 (±12.82) nd/dcer 106.17 (±19.50) nd/deir 92.85 (±11.74) nd/deer 101.03 (±15.68) ir = internal rotation; er = external rotation; sd = standard deviation; cnd er/ir = concentric non-dominant external rotation/internal rotation; cd er/ir = concentric dominant external rotation/internal rotation; end er/ir = eccentric non-dominant external rotation/internal rotation; ed er/ir = eccentric dominant external rotation/internal rotation; nd/dcir = non-dominant/dominant concentric internal rotation; nd/dcer = non-dominant/dominant concentric external rotation; nd/deir = non-dominant/dominant eccentric internal rotation; nd/ deer = non-dominant/dominant eccentric external rotation. *significant difference (p<0.05). 16 sajsm vol. 25 no. 1 2013 age, playing position, body mass index (bmi) or a history of injury. it was previously found that age could be a risk factor for decreased flexibility of shoulder rotators.[17] this could be related to the ageing of the glenohumeral soft tissue, which may be accelerated by the training and injuries associated with rugby.[17] deficiencies in rom can be regarded as a risk factor for future injuries. the areas affected by decreased rom are obviously less mobile. consequently, the joint’s supporting structures are dynamically loaded and susceptible to intrinsic injury. the results further indicate a higher prevalence of abnormal thoracic posture than reported in the literature for a non-sporting population. in the latter, 66% of subjects had a forward head, 60% had thoracic spine kyphosis, and 38% had rounded shoulders.[2] this higher prevalence could have been attributed to the poor flexibility of certain anatomical structures, incorrect strength training, or incorrect conditioning techniques applied among the players. to our knowledge, no research has been done on incorrect training techniques among rugby union players and the association thereof with poor posture. however, it has been found that decreased resting length of the pectoralis minor muscle could have a negative influence on scapular kinematics. therefore, a strength programme where there is an imbalance between pectoralis major strengthening (too much) v. latissimus dorsi strengthening (insufficient), may contribute towards a shortened pectoralis major muscle. this may also be exaggerated by insufficient stretching of the pectoralis major muscle. this could result in a scenario where posture, and consequently scapular kinematics, may be negatively influenced, ultimately increasing the risk of injury. however, there is an argument that certain postural deviations such as abducted scapulae and rounded shoulder posture may be advantageous for contact sport athletes. the theory is that this posture allows the athlete to assume a tuck or covered-up position quickly before making contact with defending players. however, this seems to be a matter of opinion, and no sufficient scientific data exist to confirm this theory. some believe that a link exists between posture and rom. rom loss may be directly attributed to changes in thoracic posture. such changes may cause a reduction in the sub-acromial space, which may cause impingement of supra-humeral soft tissue and subsequently reduce the overall rom and increase the likelihood of injury. theoretically, the high percentage of postural deformities within this group, given the high physical demands placed on rugby union players, could make this group susceptible to future shoulder injury. poor posture, therefore, not only influences rom but also impedes optimal scapular kinematics. knowledge of scapular muscle timing patterns is vitally important in terms of our understanding of the behaviour of the joint system, particularly under demanding circumstances. it is relevant to profile rugby union players with regard to these patterns. emg analyses present information on the sequence in which the scapular stabilisers fire during shoulder movement along a scapular plane. in this study the consensus sequence was: (i) serratus anterior, (ii) lower trapezius, (iii) infraspinatus, and (iv) upper trapezius. previous research regarding emg analysis of rugby players’ scapulothoracic muscles is limited, but the sequence of muscle activation patterns in selected shoulder girdle muscles during a front-on tackle in asymptomatic rugby players has previously been investigated.[5] the authors found a consistently earlier activation of serratus anterior compared with the pectoralis major, biceps brachii, latissimus dorsi and infraspinatus. in accordance with our study, even though different movements were measured, the results also indicated that the serratus anterior was the first muscle to fire before the other muscles tested. the influence of a superior labral tear from anterior to posterior (slap lesion) on the onset of emg activity in shoulder muscles during a front-on tackle among professional rugby union players has also been investigated.[18] again, results indicated that the onset of serratus anterior muscle activity occurred significantly earlier than the other muscles examined. this was seen, despite a trend towards a delay in activation time of all the other muscles within the injured group.[19] it is obvious that serratus anterior plays a significant role in the initial stabilisation of the scapulothoracic joint in a simulated tackle situation. it is postulated that a delay in the activity of serratus anterior, and the subsequent impairment in scapular control, would allow the humeral head to translate anteriorly and superiorly when the humerus reached an abducted position in the tackle situation. this could ultimately have a detrimental effect on the dynamic stability of the glenohumeral joint. [19] during our study the most frequent firing order for the trapezius muscles was the lower trapezius second and the upper trapezius fourth. it has been postulated that an early activation of the stabilising muscles at the proximal scapulothoracic joint is important for maintaining proper scapulothoracic stability throughout glenohumeral movement, and that the correct sequence of these muscles’ activity is critical for normal scapular kinematics.[1] the muscles that aid the serratus anterior in providing dynamic stability to the scapula, provide a force by coupling around the scapula.[8] the infraspinatus plays a role in posterior glenohumeral joint stability, but its ability to provide early support to this joint is apparently impaired by injury. it has been shown that the infraspinatus activates significantly earlier than the pectoralis major and latissimus dorsi during a simulated tackle situation, but that this earlier activation is not seen among injured players. this may be indicative of a failure of the local control system that could possibly lead to increased stress on the shoulder support structures. all the muscles that were tested by means of emg during this study have important functions regarding the normal shoulder function of rugby players, and it has been shown that the correct timing of the activation of these muscles is significant.[1,8,19] altered muscle activation patterns could contribute towards scapular dyskinesia or indicate underlying injury, but normative data regarding correct muscle activation patterns could possibly aid in identifying potential weaknesses among scapular stabilisers before injury occurs. during this particular study, the antagonist/agonist ratio regarding concentric isokinetic shoulder rotation of the right shoulder was only 55%, while that of the left shoulder was 64%. these findings are comparable with those of another study[17] where a concentric external/internal rotator muscle ratio of 64% and 56% was reported for rugby backline and forward players, respectively. in both studies, the suggested antagonist/agonist muscle-strength ratio of 65%[16] was not found. this could be relevant due to the fact that muscle imbalances around a specific joint may increase the risk of injury to athletes.[16] the statistically significant difference between the players’ dominant and non-dominant antagonist/agonist ratios in the current study is also noticeable. it is unclear why the dominant shoulders generally tended to have weak antagonist/agonist ratios. the tackle is the phase of play in which most game injury events occur.[20] if rugby players sajsm vol. 25 no. 1 2013 17 generally tend to tackle with their dominant shoulder, the possibility could exist that training and tackling over a period of time may have a detrimental effect on the soft-tissue supporting structures around the shoulder joint. this may impair normal functioning and, even though players may not perceive being injured, the wear and tear may be manifested in inadequate shoulder-strength ratios. another area of interest lies in the fact that bilateral comparisons displayed that the participants had, on average, stronger concentric ir and er strength on the non-dominant than the dominant side. despite the fact that varied results have been found regarding dominant v. non-dominant shoulder strengths for overhead athletes, it has generally been found that the dominant side is as strong as, [21] or stronger than,[22] the nondominant side. the findings of our study are therefore contrary to those of previous research and may be indicative of the weakness of our participants’ dominant concentric ir and er strength. study limitations certain limitations of our study should be acknowledged. we employed the new york posture test due to a lack of objective posturemeasurement techniques; however, this test was initially designed to classify adolescents and is therefore not ideal for our group of participants, of whom a large proportion were beyond the adolescent stage (range 17 31 years). secondly, regarding rom measurement, a more scientific and objective method is required than employed in this study. lastly, with regard to the measurement of scapular muscle activation patterns, the information would be more relevant if the muscles were to be tested during more functional, rugby-applicable movements, such as tackling, for instance. conclusion a large percentage of the participants in our study displayed non-ideal or unsatisfactory flexibility of the shoulder internal rotators. more than two-thirds displayed forward shoulders and more than half of the participants had unsatisfactory or non-ideal head positions. these are all indicative of a kyphotic posture. the firing sequence in abduction in a scapular plane and in both shoulders was: (i) serratus anterior, (ii) lower trapezius, (iii) infraspinatus, and (iv) upper trapezius. as the participants were uninjured, this firing order may indicate the normal sequence of rugby players’ scapular stabilisers during abduction in a scapular plane. it appears that the firing order of serratus anterior, prior to those of the other muscles studied, may be important for rugby players to maintain healthy shoulder function. the isokinetic shouldermuscle strength and ratios indicated a possible deficiency with regard to er strength in the dominant shoulder. this is possibly manifested in an unsatisfactory antagonist/agonist shoulder rotation ratio. the profile of the thoracic posture of the participants presents an image of a kyphotic rugby player with an inappropriate rom. this, in combination with an apparent weakness of right shoulder external rotator strength among the players, could have an impact on the prevalence of future injury from a biomechanical point of view, especially in the game of rugby with ever-increasing physical demands placed on players. by identifying these apparent musculoskeletal weaknesses, it may be possible to rectify them pro-actively with prehabilitation. conflict of interest. the authors have no conflicts of interest to declare. references 1. wadsworth d, bullock-saxton j. recruitment patterns of the scapular rotator muscles in freestyle swimmers with subacromial impingement. int j sports med 1997;18(8):618-624. [http://dx.doi.org/10.1055/s-2007-972692] 2. brooks j, fuller c, kemp s, reddin d. epidemiology of injuries in english professional rugby union: part 1, match injuries. br j sports med 2005;39(10):757766. [http://dx.doi.org/10.1136/bjsm.2005.018135] 3. funk l, snow m. slap tears of the glenoid labrum in contact athletes. clin j sport med 2007;17(1):1-4. [http://dx.doi.org/10.1097/jsm.0b013e31802ede87] 4. griegel-morris p, larson k, mueller-klaus k, otis c. incidence of common postural abnormalities in the cervical, shoulder, and thoracic regions and their associations with pain in two age groups of healthy subjects. phys ther 1992;72(6):426-431. 5. greenfield b, catlin p, coats p, green e, mcdonald j, north c. posture in patients with shoulder overuse injuries and healthy individuals. j orthop sports phys ther 1995;21(5):287-294. 6. david g, magarey m, jones m, dvir z, turker k, sharpe m. emg and strength correlates of selected shoulder muscles during rotations of the glenohumeral joint. clin biomech 2000;15(2):95-102. [http://dx.doi.org/10.1016/s0268-0033(99)000522] 7. kibler w. the role of the scapula in athletic shoulder function. am j sports med 1998;26(2):325-337. 8. cools a, witvrouw e, declercq g, danneels l, cambier d. scapular muscle recruitment patterns: trapezius muscle latency with and without impingement symptoms. am j sports med 2003;31(4):542-549. 9. herrington l, horsley i. electromyographic analysis of selected shoulder muscles during a rugby football tackle. sports med arthroscopy rehab ther tech 2009;1:10. [http://dx.doi.org/10.1186/1758-2555-1-10] 10. wilk k, obma p, simpson c, cain e, dugas j, andrews j. shoulder injuries in the overhead athlete. j orthop sports phys ther 2009;39(2):38-54. [http://dx.doi. org/10.2519/jospt.2009.2929] 11. le roux j, codine p, thomas e, et al. isokinetic evaluation of rotational strength in normal shoulders and shoulders with impingement syndrome. clin orthop 1994;304:109-115. 12. coetzee f, mcdonald t, kilian j. a comparison of maximal torque levels of the different planes of movement of the shoulder-girdle complex for different types of sports. s afr j res sport phys educ rec 2002;24(1):17-27. 13. magee d. orthopaedic physical assessment. 4th ed. philadelphia: saunders, 2002:1020. 14. hermens hj, freriks b, merletti r, et al. [seniam 8] european recommendations for surface electromyography; deliverable of the seniam project. nijmegen, the netherlands: roessingh research and development, 1999. 15. hunter a, st claire gibson a, lambert m, nobbs l, noakes t. effects of supramaximal exercise on the electromyographic signal. br j sports med 2003;37(4):296-299. [http://dx.doi.org/10.1136/bjsm.37.4.296] 16. bak k, magnusson s. shoulder strength and range of motion in symptomatic and pain free elite swimmers. am j sports med 1997;25(4):454-459. [http://dx.doi. org/10.1177/036354659702500407] 17. fernández j, aravena r, verdugo r, echeñique s, fei to m, rex f. glenohumeral rotation range deficit in professional rugby players: a cross sectional study. int j sport sci 2011;7(22):39-47. [http://dx.doi.org/10.5232/ricyde2011.02204] 18. edouard p, frize n, calmels p, samozino p, garet m, degache f. influence of rugby practice on shoulder internal and external rotators strength. inter j sports med 2009;30(12):863-867. [http://dx.doi.org/10.1055/s-0029-1237391] 19. horsley i, herrington l, rolf c. does a slap lesion affect shoulder muscle recruitment as measured by emg activity during a rugby tackle? j orthop surg res 2010;5(1):1-10. [http://dx.doi.org/10.1186/1749-799x-5-12] 20. fuller c, brooks j, cancea r, hall j, kemp s. contact events in rugby union and their propensity to cause injury. br j sports med 2007;41(12):862-867. [http:// dx.doi.org/10.1136/bjsm.2007.037499] 21. mikesky a, edwards j, wigglesworth j, kunkel s. eccentric and concentric strength of the shoulder and arm musculature in collegiate baseball pitchers. am j sports med 1995;23(5):638-642. [http://dx.doi.org/10.1177/036354659502300520] 22. chandler t, kibler w, stracener e, ziegler a, pace b. shoulder strength, power, and endurance in college tennis players. am j sports med 1992;20(4):455-458. [http:// dx.doi.org/10.1177/036354659202000416] http://dx.doi.org/10.1055/s-2007-972692] http://dx.doi.org/10.1136/bjsm.2005.018135] http://dx.doi.org/10.1097/jsm.0b013e31802ede87] http://dx.doi.org/10.1016/s0268-0033 http://dx.doi.org/10.1186/1758-2555-1-10] http://dx.doi.org/10.2519/jospt.2009.2929] http://dx.doi.org/10.2519/jospt.2009.2929] http://dx.doi.org/10.1136/bjsm.37.4.296] http://dx.doi.org/10.1177/036354659702500407] http://dx.doi.org/10.1177/036354659702500407] http://dx.doi.org/10.5232/ricyde2011.02204] http://dx.doi.org/10.1055/s-0029-1237391] http://dx.doi.org/10.1186/1749-799x-5-12] http://dx.doi.org/10.1136/bjsm.2007.037499] http://dx.doi.org/10.1136/bjsm.2007.037499] http://dx.doi.org/10.1177/036354659502300520] http://dx.doi.org/10.1177/036354659202000416] http://dx.doi.org/10.1177/036354659202000416] sajsm vol 24 no. 1 2012 3 original research introduction cricket is a dynamic sport that involves many abstract skills and movements. to enhance these skills and movements, many players ensure that their bodies are kept fit and strong.1-3 there are three unique aspects of the game (bowling, batting and fielding) which are associated with risk of injury.2,3 currently the male south african cricket team is ranked 3rd in test cricket, 3rd in one-day international cricket and 4th in t20 cricket (as of 06/01/2011).4 to possess such a strong national side, the building blocks and foundations have to be laid at school level to meet the required standards when schoolboy cricket players develop and transcend to provincial and national levels.5 musculoskeletal pain can occur in various ways while playing cricket: a player being struck by a ball or bat, rapid rotational movements, sliding and diving, collisions with other players and overuse injuries.5-8 it is important that players are taught that prevention is better than cure.9 some players do not have adequate physical training, and are therefore not physically prepared for cricket.10 because of this, their muscle strength, endurance, agility and fitness on the field may not always be adequate for the game of cricket.3 international cricket studies mostly concentrate on young fastbowlers and their injuries.11,12 dennis et al. focused on bowling workloads regarding injury rates in young fast-bowlers.11 hardcastle et al. focused on spinal abnormalities in young fast-bowlers.12 a number of studies conducted in south africa identified a prevalence of cricket-related musculoskeletal injuries among elite cricketers.1,6,8 these studies found that the most common anatomical sites of injury were lower limb, followed by upper limb and lower back.5 stretch et al. reported that the lower limbs (50%), upper limbs (23%), and back and trunk (23%) were most commonly injured in south african cricketers.5 milsom et al. reported that in south african schoolboy cricketers 34% of injuries were sustained to the upper limbs, 34% to the lower limbs and 31% to the back and trunk.7 to the best of the researchers’ knowledge, no studies have investigated injuries and pain among schoolboy cricket players in specific geographical regions within south africa. the aim of this study was to document cricket-related musculoskeletal pain among schoolboy cricket players in kwazulu-natal. methods this was a retrospective study which documented cricket-related musculoskeletal pain over a 12-month period and employed both qualitative and quantitative designs. subjects were adolescent male recreational cricketers who participated voluntarily after their parents had given their informed consent. child assent forms were provided for the schoolboy cricket players to complete. the subjects (n=234) were recruited from five (5) secondary schools in kwazulu-natal: glenwood high, kloof high school, durban high school, westville boys high and pinetown boys high school. these schools were chosen because they were considered to be among the top cricketing schools, according to the kwazulu-natal cricket union. the players’ ages ranged from 14 to 17 years. the identity of all the subjects was kept anonymous and confidential. ethical clearance for the study was obtained from the research committee of the faculty of health sciences at the university of kwazulu-natal-westville. reasons for recruiting male subjects are as follows: • the participation rate in cricket is greater among males than females. • a homogenous male cohort allows for findings to be more reliable. therefore, inclusion of females into the cohort would have increased prevalence of cricket-related musculoskeletal pain among adolescent cricketers in kwazulu-natal m h noorbhai (bsps (hons) biokinetics) f m essack (bsps (hons) biokinetics) s n thwala (bsps (hons) biokinetics) t j ellapen (phd) j h van heerden (dphil) department of sport science, school of physiotherapy, sport science and optometry, university of kwazulu-natal correspondence to: habib noorbhai (habib.noorbhai@yahoo.com) abstract objectives. this study investigated the prevalence and nature of cricket-related musculoskeletal pain among male adolescent cricket players (n=234) residing in the highway area of durban over a 12-month period during all the seasons of the year. methods. data were collected from five secondary schools. subjects’ participation was dependent on voluntary and parental informed consent. child assent forms were also provided for the schoolboy cricket players to complete. participants were required to complete a self-reported questionnaire probing the prevalence of musculoskeletal pain within the last 12 months. the probability was set at p≤0.05. results. a total of 188 subjects (80%) experienced cricket-related musculoskeletal pain (p<0.0001). the most common sites were the lower extremities (39%), followed by upper extremities (36%) and lower back (18%). the prevalence of cricket-related musculoskeletal pain specific to the various anatomical sites were mostly knee (30%) and lower back (29%), followed by shoulder (17%), ankle (13%) and thigh (11%). the predisposing mechanisms producing cricket-related musculoskeletal pain reported by the cricketers were direct physical trauma (83%) and over-use (17%) (p<0.0001). conclusion. male adolescent recreational cricket players reported a high prevalence of cricket-related musculoskeletal pain. the knee was the most common anatomical site. parents, guardians and coaches should pay specific caution to preliminary and extrinsic factors causing musculoskeletal pain in adolescent cricketers. 4 sajsm vol 24 no. 1 2012 the unreliability of the findings due to physiological and hormonal differences. data were collected through a self-reported musculoskeletal questionnaire (adapted from ellapen et al.13) to determine the prevalence of pain at various anatomical sites. the questionnaire (see appendix) and the relevant documentation were explained thoroughly to all subjects, to reduce recall bias. this study employed the following definition of musculoskeletal pain: ‘a sensation of agony that inhibits the individual from participating in cricket or practice for a minimum of twentyfour hours’.14 attempts to document the prevalence of musculoskeletal injury would be unreliable in the absence of medical certification. the researchers doubted that all the subjects would have kept medical records of their injuries within the previous 12 months and so, in the absence of medical records, identification of musculoskeletal pain via subject recall was deemed to be more reliable. subjects’ identification of musculoskeletal pain, types of pain, intensity of pain (according to the borg cr10 scale) and anatomical location of pain were recorded to infer musculoskeletal injury.15,16 injury rates were calculated according to a numerator variable (number of injuries sustained) linked to a denominator variable (number of hours played over the last 12 months), giving the number of injuries sustained for every hour played over the last 12 months. body mass and stature of all the subjects were measured according to the houglum protocol.17 the data were analysed descriptively (mean, mode, frequency and percentages) and inferentially (chi-square test). the level of significance was set at p≤0.05. results results demonstrated the epidemiology of pain, prevalence of pain, nature of pain and training factors. demographic and physical characteristics are reported in table 1. results showed that 188 subjects experienced cricket-related musculoskeletal pain (table 2). the predisposing mechanisms producing the pain were direct physical macrotrauma (83%) and microtrauma (17%). macrotrauma is a force produced by a single incident which causes an acute injury whereas microtrauma is a repetitive or chronic injury which lasts over a period of time.18 these types of injuries relate to the injuries sustained by the cohort in the study. the anatomical sites of cricket-related musculoskeletal pain were knee (30%), lower back (29%), shoulder (17%), ankle (13%) and thigh (11%) (p<0.0001) (fig. 1). amongst the cohort, 30% of batsmen, 28% of all-rounders, 23% of bowlers and 7% of wicket-keepers were investigated for pain (p<0.0001). the types of pain experienced by the subjects were mostly discomfort (39%), dull aching pain (32%), spasms (19%), sharp pain (19%) and swelling (17%) (table 3). the intensity of pain experienced by the subjects was moderate (34%), low (26%), uncomfortable (17%), high (13%) and severe (4%).the subjects’ duration of pain was indicated as follows: few hours (30%), few days (28%), unpredictable (25%) and continuous (17%). the average training history amongst the cohort was: 7.6 months in a year practised, 2.9 days a week practised and 126 minutes per training session (table 4). the types of training performed across the cohort were skills (25%), coordination (18%), agility training (14%), core stability (14%), aerobic training (11%), weight training (10%) and flexibility training (8%). discussion of the 234 cricket players investigated, 188 (80%) experienced cricket-related musculoskeletal pain within the last 12 months (p<0.0001). these findings support other international and local studies on cricket-related musculoskeletal pain/injury.1,5-8,11,12 the anatomical sites of the pain were knee (30%), lower back (29%), shoulder (17%), ankle (13%) and thigh (11%) (p<0.0001). the most common anatomical sites were lower extremities (39%), followed by upper extremities (36%) and lower back (18%). these results are consistent with other findings.5,7 stretch et al. reported that the lower limbs (50%), upper limbs (23%), and back and trunk (23%) were table 1. demographical and physical characteristics of sample (n=234) variables mean ± sd age (years) 15.6+1.1 body weight (kg) 69.2+13.5 stature (m) 1.71+0.15 body mass index (kg/m2) 20.8+11.7 table 2. prevalence of musculoskeletal pain among cricket players (n=188) role presence of pain (%) batsmen 30 bowlers 23 all-rounders 28 wicket-keepers 7 fig. 1. prevalence of cricket-related musculoskeletal pain at specific anatomical sites (n=188) (p<0.0001).(other = hip, jaw and mouth.) table 3. types of pain, intensity of pain and duration of pain among cricket players (n=188) types of pain % intensity of pain % duration of pain % discomfort 39 moderate 34 few hours 30 dull aching 32 low 26 few days 28 spasms 19 uncomfortable 17 unpredictable 25 sharp 19 high 13 continuous 17 swelling 17 severe 4 sajsm vol 24 no. 1 2012 5 most commonly injured in south african cricketers.5 milsom et al. reported that in south african schoolboy cricketers 34% of injuries were sustained to the upper limbs, 34% to the lower limbs and 31% to the back and trunk.7 the types of pain experienced by the subjects were discomfort (39%), dull aching pain (32%), spasms (19%), sharp pain (19%) and swelling (17%). dull aching and discomfort pain sensations are associated with muscle pain, whereas pins and needles and radial pain sensations are associated with neurological pathologies.9,17,19 in most cases the pain was musculoskeletal and not neurological. the duration of pain was indicated as follows: few hours (30%), few days (28%), unpredictable (25%) and continuous (17%). subjects experiencing continuous pain and unpredictable pain were associated with microtraumas. similarly, subjects experiencing pain within a few hours, few days or an unpredictable duration were associated with macrotraumas. the nature of pain (anatomical location of pain, types of pain, intensity of pain and duration of pain) in this study clearly indicates musculoskeletal pain pathologies, thus demonstrating the prevalence of cricket-related musculoskeletal pain. amongst the cohort, 30% of batsmen, 28% of all-rounders, 23% of bowlers and 7% of wicket-keepers were investigated for pain. these findings conflict with previous studies on schoolboy cricketers, where injuries to bowlers (47%) were found to be higher than in batsmen (30%) and fielders (23%).8 milsom et al. reported that bowling accounted for 51% of the injuries, while fielding accounted for 33%, batting for 15% and the remaining injures occurred while warming up or training.7 the differences in the above findings could be due to the different types of players participating in the study (batsmen, bowlers, fielders and wicket-keepers) and the different types of injuries sustained. an injury was defined as any physical damage that occurred during a match, practice or training session and which prevented the player from completing the match, practice or training session. these studies also included a few differences in the questionnaires where it focused on detailed times of the year for incidences in injuries and whether the injuries were recurrent or recent. the lower back and knee are mostly associated with microtrauma injuries.9 fast-bowling is associated with a high risk of lower back pain. lumbar pain, which is common among fast-bowlers, can lead to premature retirement of these players.12 this is also due to the forceful release by fast-bowlers at the popping crease of the pitch, causing the bowlers to hyperextend their backs.10,11 similarly, spin-bowlers experience lower back pain due to the pivot and lateral rotation of the hips after the ball has been released, causing the abdominal and oblique muscles to compensate for these movements.10,11 subjects who experienced knee pain were mostly batsmen and wicket-keepers. batsmen display movements either on the front foot (propelling forward) or back foot (propelling backwards) and these movements load pressure and tension on the knee and surrounding joints of the patella during flexion and extension, placing the knee joint at increased risk.10,19 similarly, wicket-keepers spend most of the time kneeling down and flexing their knees while playing, which also increases their risk of pain at the knee joint.10 it was evident that players who did not do sufficient amounts of strength training (10%) and flexibility training (8%) (p<0.0001) were more predisposed to musculoskeletal pain or injury. strength training has its benefits: an individual will become more resistant to pain or injury and can overcome pain much easier because of increased strength.9,10,19 safe strength training at this point in a cricketer’s development enhances resilience in bones, tendons, ligaments and muscles, resulting in better performance and fewer injuries.10,20 therefore more strength and flexibility training can be initiated to reduce the chances of injury and pain. however, caution should be adopted with adolescent cricketers, as their epiphyseal plates can be hindered with strength training.9 for males, 12 18 months after their growth spurt is the ideal time to start strength and flexibility training.9,20 the average training history amongst the cohort was: 7.6 months’ practice in a year, 2.9 days’ practice a week and 126 minutes per training session. subjects experienced an injury rate of 0.2 injuries for every playing hour over the previous 12 months. as adolescent cricketers and young athletes, 4 days per week of training and matches are optimal, whereas 2 3 days per week are minimal.9,11 regarding bowlers, important research was done by dennis et al., who noted that bowlers with an average of less than 3.5 rest days were at a significantly increased rate of injury and that there was also an increased risk of injury for those who bowled an average of more than 2.5 days a week.13 considering this research, more attention should be placed on bowlers with regard to sufficient rest days to reduce injury rates. although 117 (62%) subjects participated in other additional activities and sport in the cricket off-season, in all cases their musculoskeletal pain was cricket-related. a recommendation from this study is that cricket coaches should be cautious when training players with existing pain. it is advisable for coaches to utilise logbooks during training sessions to keep record of the number of hours, weeks and months trained by each player so that potential overuse injuries or recurrent pain can be minimised.10 coaches should also ensure that the technical errors of the players are corrected.10 furthermore, coaches need to be educated on the prevalence of pain and injuries that occur in cricket players, the correct techniques in cricket and how to assist schoolboy cricketers in adapting their technique to avoid potential pain and injuries. conclusion this study showed that male adolescent recreational cricket players residing in the highway area of kwazulu-natal sustained a high prevalence of musculoskeletal pain. the intrinsic factors (direct physical traumas and overuse) were the main contributors to the subjects experiencing pain. the knee was the most prevalent anatomical site of cricket-related musculoskeletal pain. it is essential that a database for male adolescent cricket players in kwazulunatal be implemented. further longitudinal investigations should be conducted among male adolescent cricket players residing in other regions in all south africa. acknowledgements the authors would like to extend their appreciation and gratitude to the cricket high schools of kwazulu-natal, dr ma noorbhai, dr ak halabi, mrs kb halabi and ms s abrahams for their assistance during the study. table 4. training history reported by subjects within the last 12 months (n=234) variables mean ± sd months/year 7.6±2.7 days/week 2.9±1.2 minutes/training session 126±22 6 sajsm vol 24 no. 1 2012 1 a p p e n d i x an epidemiological investigation into the prevalence and aetiology of cricket-related musculoskeletal pain among adolescent cricketers in kzn. personal information: surname: ____________________________ name:________________________________________ age: ____________ telephone no: (h) _________________ (cell)__________________________ gender: male female race: african white indian coloured asian body mass:__________ stature:__________ bmi:__________ what position do you play? ____________________ how long have you been playing at a school/junior provincial level: ____________________ angles right left shoulder internal rotation shoulder external rotation cubitus angle ulnar deviation q-angle training history 1. how many months in a year do you practise? 1 2 3 4 5 6 7 8 9 10 11 12 2. how many times a week do you have cricket practice? 1 2 3 4 5 6 7 8 9 10 references 1. aginsky kd, lategan l, stretch ra. shoulder injuries in provincial male fast bowlers – predisposing factors. s afr j sports med 2004;16(1):25-28. 2. myers p, o’brien s. cricket: injuries, rehabilitation and training. london: lippincott williams & wilkins, 2001:124-136. 3. petersen cj, pyne db, dawson bt, kellet ad, portus mr. comparison training and game demands of national level cricketers. j strength cond res 2011;25(5):13061311. 4. http://icc-cricket.yahoo.com.net/match_zone/team_ranking.php (accessed 6 january 2011). 5. stretch ra. cricket injuries: a longitudinal study of the nature of injuries to south african cricketers. br j sports med 2003;37:250-253. 6. giles k, musa i. a survey of glenohumeral joint rotational range and non-specific shoulder pain in elite cricketers. physther sport 2008;9(3):109-116. 7. milsom nm. barnard jg, stretch ra. seasonal incidence and nature of cricket injuries among elite south african schoolboy cricketers. s afr j sports med 2007;19(3):80-84. 8. stretch ra. the incidence and nature of injuries in schoolboy cricketers. s afr med j 1995;85:1182-1184. 9. brukner p, khan k. clinical sports medicine, revised 3rd ed. new york: the mcgraw hill company, 2009:27-105. 10. woolmer b, noakes td, moffett h. bob woolmer’s art and science of cricket. cape town: struik publishers, 2009:86-322, 464-520, 526-630. 11. dennis rj, finch cf, farhart pj. is bowling workload a risk factor for injury to australian junior cricket fast bowlers? br j sports med 2005;39:843-846. 12. hardcastle p. spinal abnormalities in young fast bowlers. aust n z j surg 1992;74b(3):421-425. 13. ellapen tj, demartinis r, hughes t, hansen c, van heerden hj. the incidence of hockey ankle injuries in kwazulu-natal. research report, university of kwazulunatal. ajpherd 2009;15(3):417-423. 14. van heerden hj. pre-participation evaluation and identification of aetiological risk factors in epidemiology of sports injuries among youths. thesis: doctor of philosophy. pretoria: university of pretoria, 1996. 15. fuller cw, ekstrand j, junge a. consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries. scand j med sci sports 2006;16(2):82-83. 16. hagglund m, walden m, ekstrand j. uefa champions league study: a prospective study of injuries in professional football during the 2001-2002 season. br j sports med 2005;39:542-546. 17. houglum pa. therapeutic exercise for musculoskeletal injuries, 3rd ed. champaign, il: human kinetics, 2010:199-254. 18. http://www.answers.com/topic/macrotrauma (accessed 6 january 2012). 19. prentice we. rehabilitation techniques for sports medicine and athletic training, 5th ed. new york: the mcgraw hill company 2011:47-92. 20. http://www.pitchvision.com/when-to-introduce-strength-and-endurance-trainingto-young-cricketers (accessed 27 january 2012). sajsm vol 24 no. 1 2012 7 1 a p p e n d i x an epidemiological investigation into the prevalence and aetiology of cricket-related musculoskeletal pain among adolescent cricketers in kzn. personal information: surname: ____________________________ name:________________________________________ age: ____________ telephone no: (h) _________________ (cell)__________________________ gender: male female race: african white indian coloured asian body mass:__________ stature:__________ bmi:__________ what position do you play? ____________________ how long have you been playing at a school/junior provincial level: ____________________ angles right left shoulder internal rotation shoulder external rotation cubitus angle ulnar deviation q-angle training history 1. how many months in a year do you practise? 1 2 3 4 5 6 7 8 9 10 11 12 2. how many times a week do you have cricket practice? 1 2 3 4 5 6 7 8 9 10 2 3. duration of training per session: 1 hr 2 hrs 3 hrs 4 hrs 5 hrs other 4. do you practise / participate in any additional activities beside cricket? gym swimming cricket rugby others 5. if so, how many times a week: 1 2 3 4 5 6 7 8 9 10 6. what type of training do you perform? weight training aerobic flexibility agility core stability skills co-ordination other: 7. can you rate your perceived rate of exertion (intensity) when you exercise from 1-20 (borg scale) __ epidemiology 8. have you sustained an injury/pain in the last 12 months while playing cricket? yes no (definition of musculoskeletal pain/injury is a sensation of agony that inhibited you from participating in cricket or practice for a minimum of 24 hours). if yes, explain how the injury/pain occurred: collision with other players struck by the ball struck by the bat rapid rotational movement over-use other: 9. have you experienced musculoskeletal pain/injury in the last 12 months? yes no 8 sajsm vol 24 no. 1 2012 2 3. duration of training per session: 1 hr 2 hrs 3 hrs 4 hrs 5 hrs other 4. do you practise / participate in any additional activities beside cricket? gym swimming cricket rugby others 5. if so, how many times a week: 1 2 3 4 5 6 7 8 9 10 6. what type of training do you perform? weight training aerobic flexibility agility core stability skills co-ordination other: 7. can you rate your perceived rate of exertion (intensity) when you exercise from 1-20 (borg scale) __ epidemiology 8. have you sustained an injury/pain in the last 12 months while playing cricket? yes no (definition of musculoskeletal pain/injury is a sensation of agony that inhibited you from participating in cricket or practice for a minimum of 24 hours). if yes, explain how the injury/pain occurred: collision with other players struck by the ball struck by the bat rapid rotational movement over-use other: 9. have you experienced musculoskeletal pain/injury in the last 12 months? yes no 3 10. where do you experience the symptoms of the pain/injury? a) neck b) shoulder c) elbow d) forearm e) hand f) middle back g) lower back h) buttock i) thigh j) knee k) lower limb l) ankle m) foot n) other:___________________ 11. what type symptoms have you experienced? dull ache numbness burning sharp spasms radiating pins and needles swelling discomfort 12. how often did you experience the above mentioned pain symptoms in the past 12 months? a) once or a few times in the day b) every few days c) once a month d) other: _______________________________________________________ 13. how long did the musculoskeletal pain/injury prevent you from participating in cricket practice? 1 day 2 days 3 days 4 days 5 days more than 5 days 14. how would you rate the intensity of the symptom you experienced? 1 2 3 4 5 uncomfortable low moderate high severe figure 1 (adapted from ellapen et al, 2009) sajsm vol 24 no. 1 2012 9 3 10. where do you experience the symptoms of the pain/injury? a) neck b) shoulder c) elbow d) forearm e) hand f) middle back g) lower back h) buttock i) thigh j) knee k) lower limb l) ankle m) foot n) other:___________________ 11. what type symptoms have you experienced? dull ache numbness burning sharp spasms radiating pins and needles swelling discomfort 12. how often did you experience the above mentioned pain symptoms in the past 12 months? a) once or a few times in the day b) every few days c) once a month d) other: _______________________________________________________ 13. how long did the musculoskeletal pain/injury prevent you from participating in cricket practice? 1 day 2 days 3 days 4 days 5 days more than 5 days 14. how would you rate the intensity of the symptom you experienced? 1 2 3 4 5 uncomfortable low moderate high severe figure 1 (adapted from ellapen et al, 2009) 4 15. how long did your pain/injury persist for? a) a few hours b) a few days c) it is continuous d) it is unpredictable 16. have you obtained the services of any of the following healthcare professionals for your musculoskeletal symptoms? a) orthopaedic surgeon b) general practitioner c) physiotherapist d) chiropractor e) biokineticist f) massage therapist g) other: _______________________________________________________________ 17. do you play through the pain/injury? yes no as a result of this action, does the musculoskeletal pain index increase? yes no samf 2012 has arrived to order your copy of the updated 2012 edition of the south african medicines formulary, contact edward or byron tel: 021 6817000 or fax: 086 600 6218 to order your copy of the updated 2012 edition of the south african medicines formulary, contact edward or byron tel: 021 6817000 or fax: 086 600 6218 original research 90 sajsm vol 23 no. 3 2011 introduction as a consequence of apartheid, racial categorisation is common in south african sport. to understand the progression of cricketers who have been previously disadvantaged because of apartheid, it is necessary to racially classify players. cricketers in this study were categorised as white (w), black african (ba) or coloured/indian (c/i). 1 whenever the category ‘black’ is mentioned alone, it refers to c/i and b/a. 1 after apartheid, the south african government and cricket south africa (csa) introduced a number of development and transformation policies to try and amend the injustices of the past. 2-4 consequently, an enormous amount of money was spent on the development of facilities, coaching, administration and cricketing skills of previously disadvantaged communities in an attempt to increase participation and facilitate cricketing excellence within the black communities. 3 the promotion of a mini cricket programme has been successful in introducing over 2 million young children to softball cricket in south africa. 5 transformation targets were also introduced as part of the transformation policy. currently, csa subscribes to targeted transformation set for all representative cricket. senior provincial teams have a target of 4 black players in a team of 11 players while junior provincial teams have a target of 6 black players in a 12-player squad. the development and transformation policies are aimed at increasing black representation and performance at all levels of cricket. 4 the effectiveness of the cricket transformation process with regard to increasing representation and performance of black cricketers at senior provincial level in south africa has previously been investigated. 1 it was found that these processes were effective in increasing participation of senior black provincial players between 1996 and 2008. there were no significant differences in the bowling performance between ba and w bowlers between the 2000/2001 and 2007/2008 seasons. this can be seen as a success of the transformation process in producing skilled ba bowlers. however, there were few skilled ba batsmen participating in senior provincial cricket. furthermore the performance of the ba batsmen was significantly worse than the w batsmen in every season between 2000 and 2008. the number and performance of ba batsmen at senior provincial level is thus a concern. if it is assumed that the junior provincial batsmen are a feeder for the senior provincial batsmen then investigating the participation and performance of junior batsmen is imperative. it has also been suggested that ba players were performing at junior provincial level but have not been afforded the opportunity in the senior teams and consequently do not feature in the senior provincial teams. 6 therefore, the aim of this study was to investigate the performance of ba batsmen at junior provincial level (u15 and u19) between 2004 and 2010, and establish whether they follow the same trend as the senior provincial players. the results of this study could impact csa’s future development and transformation policies. methods all data were taken from the u15 and u19 annual interprovincial cricket tournaments in south africa between 2004 and 2010. only 2% of all south african players were not racially classified due to insufficient information on those players and they were therefore excluded from all analyses. data of the 2005 u15 interprovincial tournament were also not available and excluded from the analysis. linear regression analysis was used to compare the percentage change in the number of players (separated according to their different racial groups) participating each year. a non-parametric independent sample (kruskal-wallis) test was used to determine the difference between the median batting averages (runs/dismissal) of the different racial groups for each year. linear regression analysis was used to compare the change in the median batting average between 2004 mogammad sharhidd taliep (phd) raeeq gamieldien (btech) sacha jane west (phd) cape peninsula university of technology, department of sports management correspondence to: mogammad taliep (talieps@cput.ac.za) an analysis of the performance of black african junior provincial cricket batsmen abstract objectives. this study investigated the difference in performance of white (w), coloured/indian (c/i) and black african (ba) cricket batsmen at a junior provincial level in south africa over a period of 7 years. methods. data of all players participating in the south african interprovincial under-15 (u15) and under-19 (u19) tournaments between the years 2004 and 2010 were analysed. the number of participants, batting averages and number of batsmen in the top 20 run scorers in the tournament were compared between groups. results. 52% of players were white and 48% were black (27% ba and 21% c/i). ba batting averages (runs/dismissal) were significantly (p<0.05) lower than w batting averages for every year from 2004 to 2010 for both the u15 and u19s. w batsmen only had significantly better batting averages than c/i for the u/15s in 2010 and for the u19s in 2009 and 2010. w batsmen dominated the top 20 run scorers in the tournament in each year for both u15s and u19s while there were few ba batsmen represented in the top 20. conclusion. the performances of ba batsmen at junior provincial level are well below those of w batsmen and appear to follow the same trend as the senior provincial batsmen. sajsm vol 23 no. 3 2011 91 and 2010. the top 20 run scorers for each year were also recorded and compared to par representation for each group. par representation was determined by calculating the percentage representation of each group relative to their total representation in that year. the following equation was used to calculate par representation: the par value was then subtracted from the actual representation of the group in the top 20 and plotted. therefore a value of 1 indicates that a group had 1 person more than the estimated par value for that group, a value of -1 indicates that a person has 1 person less than the estimated par value for that group. results the percentage of players participating in the u15 and u19 tournament is represented in table i. there appears to be relatively equal representation in the u15 and u19 interprovincial tournaments for the w (approximately 50%) and black players (approximately 50%) for each year. linear regression analysis indicates that there was a significant decrease in the percentage of ba players between 2004 and 2010 for both the u15s (r=-0.88 r 2 =0.779, p=0.020) and u19s (r=-0.98 r 2 =0.96, p<0.000). there was a significant increase in the percentage of c/i players participating in both the u15 (r=0.90, r 2 =0.802, p=0.016) and u19 (r=0.90, r 2 =0.81, p=0.006) group but no significant change in the percentage of w players participating in the both the u15 (r=0.36, r 2 =0.13, p=0.478) and u19 (r=0.69, r 2 =0.48, p=0.086) tournament between 2004 and 2010. a comparison of the batting average between the racial groups for the u15 and u19s are represented in tables ii and iii, respectively. for the u15s the ba batsmen had significantly lower batting averages than w batsmen in every year between 2004 and 2010 (table ii). there was no significant difference in the batting average between w batsmen and c/i batsmen for the u15s except in 2010, where w batsmen had significantly higher batting averages. there were also no significant differences in the batting average of c/i and b/a batsmen for the u15s except for 2007, where c/i batting average was significantly better. for the u19s, ba batsmen had significantly lower batting averages than w batsmen in every year between 2004 and 2010 (table iii). there was no significant difference in the batting average between w batsmen and c/i batsmen except in 2009 and 2010, where w batsmen had significantly higher batting averages (table iii). there were also no significant differences in the batting average of c/i and ba batsmen except for 2006, where c/i batting average was significantly better. linear regression analysis indicates that there was an improvement in the batting average of ba between 2004 and 2010 for the u19s (fig. 1). there was no significant improvement in batting average for any of the other racial groups. data of the top 20 players who scored the most runs in the interprovincial tournament for each year are represented in table iv. in the u15 group there were only two ba batsmen in the top 20 run scorers in 2004 and 2006 and one in 2007. more recently, in 2008, 2009 and 2010 there were no ba batsmen representative in the top 20 for the u15s. similarly, there are few ba batsmen in the top 20 in the u19 between 2004 and 2010. par representation (x,y,z) = (total percentage participation x 20)/ 100. where x, y, z represent w, c/i and ba respectively. table i. representation of players participating in the annual interprovincial u15 and u19 tournaments between 2004 and 2010 (data for the u15s in 2005 were not available; data are presented as percentage % and number of participants (n)) year w % (n) c/i % (n) ba % (n) total* % (n) u15 2004 50 (95) 21 (39) 30 (56) 100 (190) 2005 2006 52 (104) 20 (40) 29 (58) 100 (202) 2007 51 (102) 22 (44) 28 (56) 100 (202) 2008 53 (100) 24 (46) 23 (43) 100 (189) 2009 50 (99) 25 (50) 24 (48) 100 (197) 2010 52 (102) 25 (50) 23 (46) 100 (198) u19 2004 51.0 (101) 15.7 (31) 33.3 (66) 100.0 (198) 2005 47.6 (88) 21.6 (40) 30.8 (57) 100.0 (185) 2006 49.3 (99) 19.9 (40) 30.8 (62) 100.0 (201) 2007 54.0 (107) 20.2 (40) 25.8 (51) 100.0 (198) 2008 52.0 (105) 24.3 (49) 23.8 (48) 100.0 (202) 2009 52.7 (109) 25.6 (53) 21.7 (45) 100.0 (207) 2010 53.7 (102) 25.8 (49) 20.5 (39) 100.0 (190) * due to rounding the values may not equal 100%. table ii. a comparison of the u15 batting averages of the different racial groups between the 2004 and 2010 year race batting average (runs/dismissal) p-value 2004 w v. c/i 17.6 v. 11.0 0.135 w v. ba 17.6 v. 6.3 0.000* c/i v. ba 11.0 v. 6.3 0.100 2006 w v. c/i 18.3 v. 12.7 0.229 w v. ba 18.3 v. 9.8 0.001* c/i v. ba 12.7 v. 9.8 0.688 2007 w v. c/i 16.0 v. 13.2 0.885 w v. ba 16.0 v. 6.2 0.000* c/i v. ba 13.2 v. 6.2 0.008* 2008 w v. c/i 13.5 v. 9.7 0.196 w v. ba 13.5 v. 6.5 0.000* c/i v. ba 9.7 v. 6.5 0.221 2009 w v. c/i 17.8 v. 11.3 0.067 w v. ba 17.8 v. 7.4 0.000* c/i v. ba 11.3 v. 7.4 0.058 2010 w v. c/i 26.9 v. 21.4 0.034* w v. ba 26.9 v. 7.2 0.000* c/i v. ba 21.4 v. 7.2 0.422 *significant difference (p<0.05). 92 sajsm vol 23 no. 3 2011 table iii. a comparison of the u19 batting averages of the different racial groups between the 2004 and 2010 year race batting average (runs/dismissal) p-value 2004 w v. c/i 14.1 v. 11.2 0.524 w v. ba 14.1 v. 5.8 0.000* c/i v. ba 11.2 v. 5.8 0.208 2005 w v. c/i 14.8 v. 11.5 0.116 w v. ba 14.8 v. 7.3 0.000* c/i v. ba 11.5 v. 7.3 0.404 2006 w v. c/i 14.8 v. 11.5 0.377 w v. ba 14.8 v. 7.3 0.000* c/i v. ba 11.5 v. 7.3 0.002* 2007 w v. c/i 15.0 v. 16.5 1.000 w v. ba 15.0 v. 8.0 0.001* c/i v. ba 16.5 v. 8.0 0.078 2008 w v. c/i 15.3 v. 11.6 1.000 w v. ba 15.3 v. 9.5 0.014* c/i v. ba 11.6 v. 9.5 0.272 2009 w v. c/i 17.3 v. 10.0 0.015* w v. ba 17.3 v. 9.7 0.002* c/i v. ba 10.0 v. 9.7 1.000 2010 w v. c/i 21.0 v. 13.0 0.034* w v. ba 21.0 v. 9.3 0.000* c/i v. ba 13.0 v. 9.3 0.422 *significant difference (p<0.05). fig. 1. regression analysis of the batting averages for the u15s and u19s between 2004 and 2010. significant difference (p<0.05) represented by *. table iv. number of players in the top 20 run scorers in the interprovincial u15 and u19 tournaments between 2004 and 2010 year w (n) c/i (n) ba (n) u15 2004 14 4 2 2006 15 3 2 2007 13 6 1 2008 14 6 0 2009 15 5 0 2010 16 4 0 u19 2004 15 2 3 2005 14 1 5 2006 14 4 1 2007 15 4 1 2008 12 3 5 2009 14 3 3 2010 16 2 2 fig. 2. a representation of the number of players in the top 20 (run scorers) relative to par representation for each racial group. sajsm vol 23 no. 3 2011 93 fig. 2 represents the number of players in the top 20 run scorers relative to par representation for each racial group. in the u15s, ba batsmen were well below the par representation level in the top 20 each year. w batsmen were all above par for each year. c/i batsmen reached par in 2004 and 2009, were above par in 2007 and 2008 and below par in 2006 and 2010. for the u19s, ba batsmen were below the par in each year except 2008, where they were equal to par, while the w batsmen were all above par for each year. c/i batsmen reached par in 2006 and 2007 and were below the par in all other years. discussion the data suggest equal representation of black and w players at junior provincial level in south africa. this could be seen as a success of the development and transformation process which aims at producing provincial cricketers that are representative of all south africans. however, the transformation target for junior provincial cricket set by csa is 6 black players in a 12-man squad. equal representation is therefore not necessarily a success of transformation but a consequence of the transformation target policy. the decrease in ba players participating in the interprovincial tournaments since 2004 is a concern as one of the aims of csa is to increase participation of ba at a community and provincial level. 4 at senior level, ba players have been on the increase since 1996 1 and the current junior results are a drawback to this development and transformation process. csa has subsequently appointed retired protea fast bowler makhaya ntini as the first cricket development ambassador with the aim of identifying the problems associated with cricket in the historically disadvantaged communities and instituting the appropriate structures for a successful development programme. 7 another important aspect of the transformation process is for black players to perform at the highest standards. however, both the u15 and u19 ba batting averages were significantly worse than those of w batsmen in every year. furthermore, they were consistently below the par value for representation in the top 20 run scorers in the tournament each year. a further concern is that in 2008, 2009 and 2010 in the u15 group, there were no ba batsmen in the top 20. these batting performance results are similar to senior provincial cricket, where ba batting averages were worse than those of w batsmen in every year between 2000 and 2008. 1 the results of the current study indicate that the problem is not in the gap between junior and senior cricket but rather at grass-roots levels. there are many possible reasons for this. firstly, advanced visual perceptual processing and visual-motor skills are important for skilled batting performance. 8-11 there is evidence indicating that in south africa, ba children (aged between 4 and 7 years) have weaker visual-motor skills than w children. 12 this could hinder their batting development. the reason for the poor visual-motor development amongst ba youth could be related to cultural factors. 12 however, further investigation is required. secondly, batting is a skill that has been suggested to require a great deal of commitment, dedication and parental assistance from an early age in order to perfect the numerous number of cricket strokes. 13 in order to achieve this level of skill, thousands of hours of training are required. 14 a cricketing culture of excellence is therefore important to achieve such skill. although the ba community has a rich history of cricket dating back more than 150 years, its stronghold has mainly been in the eastern cape. 15 not surprising that the majority of ba cricketers who have represented the sa national team (proteas) at test match level come from this region. this culture of excellence is perhaps not as widespread in other areas of south africa. a reason for this is that cricket is reported to be only the fourth popular sport among juniors 16 with soccer being the favoured sport in the black communities. 17 thirdly, excellence in batting is achieved more easily through specialised batting courses, readily available training equipment and coaching which are not easily accessible to a large number of ba communities. this argument does not hold for the many ba cricketers who attend some of the best schools in sa and have access to the best coaches, facilities and support, yet they still end up becoming good bowlers. examples of these are south african fast bowler makhaya ntini, monde zondeki and lonwabo tsotsobe. finally, the lack of a ba batting icon could also play a role in the minds of young cricketers, who rather aspirer to be a fast bowler like the aforementioned players. c/i batting averages were similar to w batting averages, indicating the success of transformation in producing skilled c/i batsmen. these results closely resemble the senior provincial teams where there were little differences in the batting averages between c/i and w batsmen. 1 however, more recently (2010), c/i had significantly lower batting averages than w batsmen in both the u15 and u19 groups. this concern is also reflected in the top 20 run scorers for the u19s, where their performance is generally below the par. the w batsmen have performed consistently well between 2004 and 2010. recommendations the current focus and policies of csa are broad-based and do not distinguish between batsmen and bowlers or between c/i and ba. the data represented in this paper and in a previous published paper1 suggest that perhaps csa should adapt the current development and transformation policies to increase its focus on improving the performance of ba batsmen. conclusion ba batting performance at junior provincial level is below standard. future csa development and transformation processes should aim at specifically aiding ba batsmen from a young age. acknowledgements the authors would like to thank all the coaches and coaching managers of the various provinces for their assistance with the classification of players. a special thank you to dieter pagel from cobitech (webcricket.co.za) for supplying the player statistics. a further thank you to professor simeon davies, naomi augustyn and corrie uys for their assistance. references 1. taliep ms. effectiveness of the cricket transformation process in increasing representation and performance of black cricketers at provincial level in south africa. sjsm 2009;21(4):156-162. 2. smith j, fredericks g, basson w, nyoka m, tshoma k. transformation in cricket: report submitted to the honourable minister of sport and recreation, mr n balfour. http://www.info.gov.za/otherdocs/2002/cricket.pdf (accessed 26 july 2011). 3. ucbsa presentation group. presentation by the united cricket board of south africa to the parliamentary portfolio committee on sports and recreation. http://www.pmg.org.za/docs/2002/appendices/020903ucb.ppt (accessed 26 july 2011). 4. parliamentary monitoring group. cricket sa: transformation policy: selection of national cricket team. transformation background. http://www.pmg. org.za/files/docs/080226csa.pdf (accessed 3 march 2011). 5. cricket south africa. kfc mini cricket. http://www.cricket.co.za/development_programs.aspx?id=3 (accessed 26 july 2011). 6. parliamentary monitoring group. cricket sa: transformation policy: selection of national cricket team. http://www.pmg.org.za/report/20080226cricket-sa-transformation-policy-selection-national-cricket-team (accessed 10 february 2011). 94 sajsm vol 23 no. 3 2011 7. cricket south africa. makhaya ntini backs cricket development. http:// www.cricket.co.za/news_article.aspx?id=838&section=news&subsection= news_all (accessed 7 june 2011). 8. mann dt, williams am, ward p, janelle cm. perceptual-cognitive expertise in sport: a meta-analysis. j sport exerc psychol 2007;29:457-478. 9. müller s, abernethy b, farrow d. how do world-class cricket batsmen anticipate a bowler’s intention? q j exp psychol (colchester) 2006;59:21622186. 10. taliep ms, st clair gibson a, gray j, et al. event-related potentials, reaction time, and response selection of skilled and less-skilled cricket batsmen. perception 2008;37:96-105. 11. mann dl, abernethy b, farrow d. action specificity increases anticipatory performance and the expert advantage in natural interceptive tasks. acta psychol (amst) 2010;135(1):17-23. 12. dunn m, loxton h, naidoo a. correlations of scores on the developmental test of visual-motor integration and copying test in a south african multiethnic preschool sample. percep mot skills 2006;103(3): 951-958. 13. goughy k. where are the black batsmen? http://www.cricketweb.net/blog/ features/15.php (accessed 20 july 2011). 14. galdwell m. outliers: the story of success. london: penguin books, 2009:35-68. 15. odendaal a. the story of an african game. cape town: david phillip publishers, 200:9-55. 16. cricket south africa. the annual report 2008/2009. http://www.cricket. co.za/docs/csa/full_report.pdf (accessed 24 july 2011). 17. southafrica.info. football in south africa. http://www.southafrica.info/ about/sport/soccer.htm (accessed 22 july 2011). sajsm vol 24 no. 2 2012 65 case report case report a 21-year-old provincial rugby player complained of exerciseinduced pain in both his calves in 2007, which had been treated as shin splints, but worsened progressively over the subsequent 2 years. in 2009 he consulted a sports doctor, who measured the intramuscular pressure with a slith catheter (make of catheter unknown) diagnosing bilateral chronic exertional compartment syndrome (cecs) of the anterior compartment. he was referred to an orthopaedic surgeon who did a fasciotomy of the anterior compartments. after 6 months of rehabilitation he started playing rugby again, but the pain and discomfort in his calves became so severe that he was unable to walk after a match. in 2010 he saw another orthopaedic surgeon who consulted with the surgeon who had done the previous fasciotomy; they decided that he should also do a fasciotomy of the lateral and deep posterior compartments. in 2011 he tried to play again, but again had to stop because of the severe pain in his calves. he consulted another sports doctor who referred him for a dynamic ultrasound examination. the examination was conducted by a sports doctor (>10 years’ experience in musculoskeletal ultrasound) on a toshiba ultrasound machine equipped with a 5 7.5 mhz linear-array transducer. popliteal artery entrapment syndrome (paes) was diagnosed with dynamic duplex doppler ultrasonography. fortunately no arterial damage was present and after bilateral surgical release a few months apart he was symptom-free, except for some discomfort in the fasciotomy scars. paes is a relatively underdiagnosed cause of exercise-induced lower limb claudication. the syndrome usually affects young athletes who undertake vigorous exercise leading to muscle hypertrophy of the calf muscles which unmasks the occult disorder.¹ discussion paes was first described by a medical student anderson stuart in 1879. however, the term paes was established by love and whelan in 1965. paes is a partial or complete occlusion of the popliteal artery as a result of aberrant anatomy in the popliteal fossa.² the syndrome usually affects males younger than 30 years of age, with a male to female ratio of 15:1. bilateral involvement has been reported in up to 67% of cases.¹,² vascular causes of exercise-induced pain can be difficult to exclude from the more common overuse syndromes, such as cecs, medial tibial stress syndrome, shin splints and stress fractures. vascular causes include paes, endofibrosis (intimal hyperplasia), kinking or stenosis of the iliac artery and cystic adventitious disease.³ the differential diagnoses should also include muscle rupture, tendinopathy, effort-induced venous thrombosis, nerve impingements and fascial defects.¹ a classification of popliteal vessel entrapment has been described. there are essentially four types of anatomical anomalies causing paes (types i iv). type v includes any of the anatomical variants in types i iv but also involves the popliteal vein. type vi is a functional paes caused by hypertrophied muscle.⁴ entrapment may also occur in the absence of any anatomical abnormality. functional popliteal entrapment refers to neuromuscular claudication with lower extremity paraesthesias due to repetitive overuse or injury that causes neuromuscular irritation. these patients are younger than 24 years, mostly female, and their resting and postexercise non-invasive tests are normal. this type of entrapment occurs in the same population at risk of chronic compartment syndrome.⁵ classic presentation of paes is recurrent exercise-induced pain that usually occurs at a predictable distance or activity intensity which prevents further activity. pain relief occurs with cessation of activity.³ leg weakness, paraesthesias, transient tingling and coldness of the foot may also be present. if the diagnosis is delayed, irreversible arterial damage that can impair viability of the affected limb may occur.¹ it is also common for cecs to coexist with paes, but with cecs on its own the distal pulses remain normal.²,³ the physical examination may be completely normal if certain provocative manoeuvres and exercise are not included. to elicit a zanet oschman, elouise metherell department of sports medicine, university of pretoria zanet oschman, mb chb, msc sports medicine elouise metherell, mb chb corresponding author: z oschman (zanet@mweb.co.za) popliteal artery entrapment syndrome misdiagnosed as chronic exertional compartment syndrome in a young male athlete: role of dynamic ultrasound abstract popliteal artery entrapment syndrome (paes) is an uncommon cause of exercise-induced pain in the lower extremity of young athletes. however, it might explain the symptoms of those athletes who do not respond to treatment for the more common overuse syndromes. we present a case of a young professional male athlete who was diagnosed with bilateral chronic exertional compartment syndrome (cecs), for which he was operated on twice. his symptoms persisted for 5 years before paes was diagnosed with dynamic ultrasound, and after bilateral surgical release a few months apart, he was completely symptom-free except for some discomfort in the fasciotomy scars. s afr j sm 2012;24(2):65-66. 66 sajsm vol 24 no. 2 2012 pulse deficit the knee is hyperextended and the foot placed in forced plantar flexion. pulse loss during these manoeuvres is considered pathognomonic although pulse reduction can occur in individuals without any abnormalities.¹ non-invasive duplex doppler ultrasonography allows dynamic visualisation of the popliteal artery, and during the manoeuvres described above can help establish the diagnosis. normally the flow in the distal tibialis posterior artery and dorsalis pedis artery is highresistance triphasic flow (fig.1); during forced plantar flexion the flow becomes very weak or disappears – with release of the forced plantar flexion the flow changes to low-resistance monophasic flow (fig.2). at present magnetic resonance imaging or magnetic resonance angiography remains the diagnostic method of choice. treatment of paes typically involves surgical correction of the vascular anomaly; if there is damage to the popliteal artery, constructive surgery is needed.¹ in conclusion, this case serves as a reminder that young athletes can develop paes, an uncommon cause of exercise-induced claudication in the lower extremity. it is important to have a broad knowledge and a clear understanding of the common overuse causes and the less common vascular causes of exercise-induced pain in the lower leg to improve care of young competitive athletes. references 1. roche-nagle g, wong kt, oreopoulos g. vascular claudication in a young patient: popliteal entrapment syndrome. hong kong med j 2009;15:388-390. 2. hershman eb, tauliopolaus s. lower leg pain – diagnoses and treatment of compartment syndromes and other pain syndromes of the leg. sports med 1999;27(3):193-204. 3. pham tt, kapur r, harwood mi. exertional leg pain: teasing out arterial entrapments. current sports medicine reports 2007;6(6):371-375. 4. pillai j. a current interpretation of popliteal vascular entrapment. j vasc surg 2008;48(6 suppl):61-65. 5. turnipseed wd. popliteal entrapment syndrome. j vasc surg 2002;35:910-915. fig. 1. normal high-resistance triphasic flow.tpa = tibialis posterior artery. fig 2. post forced plantar flexion, low-resistance monophasic flow. pg95-98.indd introduction whiplash as a mechanism of injury represents forced flexion-extension trauma to the neck. 1 as a diagnosis, whiplash-associated disorder (wad) is a complex clinical manifestation of neck pain, headaches, nonspecific neurological complaints, cognitive symptoms and emotional complaints. 2-5 wad is a common and costly disorder that places a social and an economic burden on health care systems, communities and the insurance industy. 6,7 in 1995 the quebec task force published an evidence-based report on the classification and treatment of wad. the classification of wad complaints was graded on a scale of 0 iv, depending on severity and extent of injury. 8-15 halderman et al. went one step further and included a detailed management plan according to the grading of the injury. 16 the grading was developed to guide and facilitate clinicians in their choice of treatment and management. however, there is still no guideline in the literature that unequivocally supports any single treatment in the care of wad. 5 it is generally accepted that active treatment is favoured over passive modalities. 17 furthermore, excessive passive health care utilisation for a wad injury may result in a slower recovery. 18 there is consensus in the literature that passive coping strategies are associated with a poorer prognosis compared with strategies where patients play an active and self-reliant role in their recovery. 19 an active therapy such as exercise prescription has been shown to be superior to a solely passive intervention. 20 in addition, many hands-on treatments such as manipulations, mobilisations, transcutaneous electrical nerve stimulation (tens), and interferential therapy (ift) have been found to be more effective when used in combination with an exercise component. 6,16,21,22 moore et al. suggested that the goal of treatment should be to improve function, empower the wad sufferer, return the patient to normal activity and, lastly, relieve symptoms. 6 the management focus for wad, especially when chronic, should be to resume or maintain a normal lifestyle, with decreasing attention on pain and symptoms. 19,23 another compounding factor in the choice of management is the patient’s preference for health care and choice of care, which is influenced by personal and environmental experiences. 22 the jury is still out on the effect that patient preferences have on clinical outcomes, 24 but it does need to be taken into consideration. 25 there is good evidence to support the recommendation of an early return to usual activity 6,21,26,27 or to ‘act as usual’. 20 providing information, advice and education are also strongly suggested in the literature. 18,19,28 therapy that includes an exercise component is generally perceived as being superior to therapies that do not include exercise. 6,10,17,19-21 gross et al. noted strong evidence for pain reduction, improved function and positive, global perceived effect for therapy that combined exercise with manipulation/mobilisation. 29,30 in a review of randomised controlled trials (rcts) of non-invasive interventions for wad, conlin et al. found consistent evidence for the support of mobilisation for acute wad. in the same study, moderate evidence was found for the effectiveness of a multimodal original research popular physical therapy modalities in the management of whiplash-associated disorders abstract objectives. the aim of this study was to determine current physiotherapy practice in private clinics across the uk in the management of whiplash-associated disorder (wad) injuries. design. all treatment reports provided to a private health care company between january 2008 and july 2010 (n=365) were included and analysed to determine the following: the treatments favoured in the management of whiplash; the number of sessions used on average; and the main reasons for discharge. results. joint mobilisations, stretches and mobility exercises were favoured in the management of acute whiplash treatment and were used in 74%, 68% and 61% of cases, respectively. the most popular treatments in chronic whiplash, in order of preference, were: stretches (73%), joint mobilisations (69%) and soft-tissue massage (63%). on average, physiotherapists used 4.46 sessions and 7.21 modalities per patient. although the outcome measures were limited to reason for discharge, the majority of patients were discharged because of ‘treatment complete/self management sufficient’, which may be assumed to be a favourable recovery for 79% of patients. conclusion. this study found that physical therapists across the uk generally use evidence-based modalities in the treatment of whiplash. however, there remains a need to emphasise and embrace a more educational and active approach to the management of these injuries. the study recommends a protocol for treating wad that includes supplementing therapeutic modalities with an exercise component, and routinely providing information and advice to ‘act as usual’. correspondence: estelle watson iprs (ltd) maple place south woodmead office park 145 western service rd woodmead, 2157 tel: 082-8112688 e-mail: estelle.owen@gmail.com estelle dorothy watson (m biokinetics)1 yoga coopoo (dphil, facsm)2 1 iprs (ltd), johannesburg 2 centre for exercise science and sports medicine, university of the witwatersrand, johannesburg sajsm vol 22 no. 4 2010 95 intervention inclusive of an exercise component. 30,31 the efficacy of spinal manipulations versus other treatments in the management of wad is still being debated in the literature. 32 this begs the question (with very little guidance provided to clinicians on the management of wad): what treatment is generally preferred by physiotherapists? surveys have been conducted to assess clinical practice for wad and other musculoskeletal (ms) injuries in emergency departments, 33,34 but minimal information exists on preferred modalities used by physiotherapists in private practice in the uk. are clinicians making use of evidence-based medicine and guidelines in the literature, and do these modalities bring about the expected outcome? the aim of this study was to assess, over a period of 2.5 years, which treatment is most frequently used by physiotherapists in the treatment of wad in private practices across the uk. methods setting an observational, retrospective cross-sectional study was completed. we conducted this study through a uk-based private rehabilitation company that provides treatment on behalf of various industrial sector employers. all physiotherapists are routinely expected to provide treatment reports for the patients referred to them. it must be noted that all reports were filled in at the discretion of the practitioner, and no formal training was provided. the reports that were sent to the company from january 2008 to july 2010 were gathered and assessed. patients inclusion criteria consisted of all cases with the term ‘whiplash’ in the diagnosis, which coincided with the neck as the primary injury region. only 10% were graded according to the quebec task force classification for wad or similar, and therefore inclusion criteria extended to include wad grade 0 iii and all those with no specific grading. exclusion criteria included secondary injuries of the upper or lower limbs, and severe pathological findings or wad grade iv. patients still being treated were excluded. data analysis simple descriptive statistics were used to describe the overview of treatment intervention choices based on the data collected. a total of 365 wad cases were found in the search. for each case, physiotherapists were made to select, from a variety of choices, the modality used during treatment. they were able to select as many modalities as necessary. these data were then measured to assess which modalities were preferred or most frequently used in the treatment of wad. the information was divided into three main categories for analysis. firstly, all wad cases were examined (n=365). these cases were then further divided into acute wad only (n=205) and chronic wad only (n=160) to examine whether treatment differed according to the classification of the injury. literature reports vary concerning the terms ‘acute’, ‘sub-acute’ and ‘chronic’. 27 vernon et al. 27 and schellingerhout et al. 35 define acute as clinical symptoms lasting no longer than 4 weeks. 36-38 this definition was used for the purpose of the study. chronic was classified as symptom persistence for any condition of more than 4 weeks’ duration. for each category the following areas were assessed: (i) the type and preference of treatment used; (ii) the average number of treatment modalities used; (iii) the average number of treatment sessions attended; and (iv) the reasons for discharge for each intervention. results routine intervention for whiplash-associated disorders results are shown for all whiplash cases (fig. 1) as a percentage for usage in each intervention category. the most popular treatment choices were joint mobilisations and stretches, all used in over 70% of wad patients. mobility and massage were also preferred interventions, used in 60% or more of all patients. provision of information on the injury, postural rehabilitation and strengthening were also common, all used in over 40% of patients. for the management of acute wad (table i), physiotherapists used joint mobilisations in over 70% of all patients. they opted for a more active, exercise-therapy approach, with mobility and stretches being used in more than 60% of all acute cases. soft-tissue massage was used marginally less in the acute phase, but was nevertheless favoured in 59% of patients. strengthening, information on the injury, and postural therapy were also all used in over 40% of patients. in comparison, the most popular choice of treatment in the management of chronic wad was stretches, used in 74% of all patients (fig. 2). soft-tissue massage and joint mobilisations continued to be used in over 60% of all patients, with mobility used less frequently than in the acute phase. most physiotherapists continued to use strengthening, information on the injury, and postural therapy as favoured treatment options (44%, 45% and 44% of cases, respectively). treatment sessions the overall average number of treatment sessions used was 4.46 per patient, which was marginally higher for acute wad versus chronic wad treatment (4.5 and 4.4, respectively). the average number of modalities used per patient was 7.21, which remained unchanged for acute and chronic wad (fig. 3). reasons for closure the only outcome measure available from these data was reason for discharge, and physiotherapists were prompted to select the most appropriate reason from a stipulated list. for the majority of patients, for both acute and chronic wad, the outcome was favourable and no further treatment was required because of a good recovery (81% and 96 sajsm vol 22 no. 4 2010 fig. 1. preferred interventions for chronic and acute wad patients (n=365). the most frequently used interventions were joint mobilisations, stretches and soft-tissue massage. 76%, respectively). non-arrival for treatment appeared to be more common in chronic (7%) than in acute (2%) cases, as well as for patients not continuing with treatment (8% and 3%, respectively). other reasons are shown in fig. 4 and comprised the minority (<5%) of cases. discussion the results suggest that there is a strong preference for the use of joint mobilisations, stretches, mobility exercises and soft-tissue massage in the treatment of both acute and chronic whiplash. there was much concordance with the use of postural therapy and strengthening as readily adopted treatment modalities in the management of wad. very little variance was shown between choice of treatment for acute and chronic whiplash. clinicians reportedly treat most patients in accordance with conlin et al.’s treatment, 31 specifi cally in their support of the use of mobilisation in the acute phase of a wad injury. there is a lack of high-quality evidence to support clinical decisions for one type of treatment above another for wad. the literature does, however, strongly suggest the use of manipulation, mobilisation and exercise in the management of low-grade whiplash injuries. there is also strong evidence for providing education on injuries, and advice to stay active 6,21 or ‘act as usual’. 26 although these have been associated with a positive effect on clinical outcomes, 18 data from this study show that these suggestions are used in fewer than half of patients. unfortunately, the type and content of the information provided during treatment are not detailed in this study. furthermore, one can ascertain whether clinicians are providing advice to ‘act as table i. a comparison of the choice of treatment reported by physiotherapists treatment modality chronic wad (%) (n=160) acute wad (%) (n=205) stretches 73 68 joint mobilisations 69 74 soft-tissue massage 63 59 mobility 59 61 information on the injury 45 48 postural modifi cations 44 49 postural work 44 49 strengthening 44 41 trigger point release 38 33 heat/ice 36 35 work/ergonomic advice 34 33 ultrasound/interferential 29 34 myofascial release 23 17 manipulations 18 17 core stability 16 17 acupuncture/dry needling 14 11 functional rehabilitation 13 16 work-focused rehabilitation 12 11 traction 11 8 proprioception 9 8 neural mobilisation 9 7 muscle energy techniques 6 9 strapping/taping 6 8 cross frictions 4 5 laser therapy 2 0 other modalities 1 2 pnf 1 2 cardiovascular exercise 0 0 isokinetics 0 0 gait training 0 0 fig. 2. a comparison of treatment usage in chronic (n=160) versus acute (n=205) wad. joint mobilisations and stretches were popular treatments, the latter being used more favourably in the treatment of chronic wad. fig. 3. a summary of the treatment, depicting number of sessions (grey bar) and number of modalities (black bar) used per patient. fig. 4. summary of response to treatment, showing the discharge reasons for acute wad (black bars) and chronic wad (grey bars). the majority of patients were discharged because of ‘treatment complete/self management suffi cient’. sajsm vol 22 no. 4 2010 97 98 sajsm vol 22 no. 4 2010 usual’ or ‘return to usual activities’. encouragement and reassurance should also play an important role in treatment. future studies should assess the specifics of the information provided, and the effect that these contribute towards recovery. current evidence suggests the use of manual therapies in conjunction with an exercise component. 21,22 it is, however, worthwhile to note that a strengthening component was used in fewer than half of all patients treated in this study. passive treatments, such as soft-tissue massage, still tended to be popular despite warnings of clinical dependence and ineffectiveness for wad sufferers. 26 despite numerous systems in place for the grading and classification of wad, 16 the current study found the practitioners’ diagnoses to be lacking in this regard. only 10% of cases (n=38) were found to be correctly classified specific to the quebec or other classifications in the literature. a more thorough classification system will help to facilitate clinical judgement and reasoning behind a choice of treatment and an expected outcome. conclusion the use of joint mobilisations, stretches and soft-tissue massage in the treatment of wad is common and widespread among physiotherapists. the traditional use of passive therapies is no longer considered best practice. the temporary relief and encouraged dependence provided by these therapies may prolong recovery. the societal, financial and clinical implications of this will only increase the burden on society. therefore, we recommend a management protocol for wad that includes providing education and advice, and using therapeutic modalities in combination with an exercise component. there remains a need in clinical practice to embrace an emphasis on active and educational care as routine practice. acknowledgements we would like to acknowledge iprs for the use of their data and resources to conduct this study, as well as all the physiotherapists and patients who participated directly and indirectly in the completion of this study. references 1. kasch h, qerama e, kongstead a, bach fw, bendix t, jensen ts. deep muscle pain, tender points and recovery in acute whiplash patients: a 1-year follow up study. pain 2008;140:65-73. 2. carstensen tbw, frosthold l, oernboel e, et al. post-trauma ratings of pre-collision pain and psychological distress predict poor outcome following acute whiplash trauma: a 12 month follow up study. pain 2009;139:248-259. 3. coté p, cassidy jd, carroll l. is a lifetime history of neck injury in a traffic collision associated with prevalent neck pain, headache and depressive symptomatology? accid anal prev 2000;32:151-159. 4. holm lw, carroll lj, cassidy jd, et al. the burden and determinants of neck pain in whiplash-associated disorders after traffic collisions. results of the bone and joint decade 2000-2010 task force on neck pain and its associated disorders. j manipulative physiol ther 2009;32(2s):s61-s69. 5. söderlund a, bring a, asenlof p. a three group study, internet based, face-to-face based and standard-management after acute whiplash associated disorders (wad) – choosing the most efficient and cost effective treatment: study protocol of a randomized controlled trial. bmc musculoskeletal disorders 2009;10:90. 6. moore a, jackson a, jordan a, et al. clinical guidelines for the physiotherapy management of whiplash-associated disorder. london: chartered society of physiotherapy, 2005. 7. nieto r, mirő j, huguet a. the fear-avoidance model in whiplash injuries. eur j pain 2009;13:518-523. 8. carroll lj, hogg-johnson s, van der velde g, et al. course and prognostic factors for neck pain in the general population: results of the bone and joint decade 2000-2010 task force on neck pain and its associated disorders. j manipulative physiol ther 2009;32(2s):87-96. 9. carroll l, holm lw, hogg-johnson s, et al. course and prognostic factors for neck pain in whiplash-associated-disorders (wad). j manipulative physiol ther 2009;32(2s):98-106. 10. guzman j, hurwitz el, carroll lj, et al. a new conceptual model of neck pain. j manipulative physiol ther 2009;32(2s):s17-s28. 11. lamb se, williams ma, withers e, et al. a national survey of clinical practice for the management of whiplash associated disorders in uk emergency departments. emerg med j 2009;26(9):644-647. 12. poorbough k, brismé jm, phelps v, sizer ps. late whiplash syndrome: a clinical science approach to evidence-based diagnosis and management, 2008 world institute of pain. pain 2008;8(1):65-89. 13. söderlund a, denison e. classification of patients with whiplash associated disorders (wad): reliable and valid subgroups based on the multidimensional pain inventory (mpi-s). eur j pain 2006;10:113-119. 14. tenenbaum a, rivano-fischer m, tjell c, edblom m, sunnerhagen, ks. the quebec classification and a new swedish classification for whiplash-associated disorders in relation to life satisfaction in patients at high risk of chronic functional impairment and disability. j rehabil med 2002;34:114-118. 15. williamson e, williams m, hansen z, joseph s, lamb se. development and delivery of a physiotherapy intervention for the early management of whiplash injuries: the managing injuries of the neck trial (mint) intervention. physiotherapy 2009;95:15-23. 16. haldeman s, carroll l, cassidy d, schubert j, nygren a. the bone and joint decade 2000-2010 task force on neck pain and its associated disorders executive summary. j manipulative physiol ther 2009;32(2s):5759. 17. scholten-peeters ggm, verhagen ap, bekkering geb, et al. prognostic factors of whiplash-associated disorders: a systematic review of prospective cohort studies. pain 2003;104:303-322. 18. hurwitz el, carragee ej, van der velde g, et al. treatment of neck pain: non-invasive interventions. results of the bone and joint decade 20002010 task force on neck pain and its associated disorders. j manipulative physiol ther 2009;32(2s):141-175. 19. nicholas mk. pain management in musculoskeletal conditions. best practice res clin rheumatol 2008;22(3):451-470. 20. ferrari r, russell as. regional musculoskeletal conditions: neck pain. best practice res clin rheumatol 2003;17:57-70. 21. douglass ab, bope et. evaluation and treatment of posterior neck pain in family practice. j am board fam pract 2004;17:s13-22. 22. guzman j, haldeman s, carroll lj, et al. clinical practice implications of the bone and joint decade 2000-2010 task force on neck pain and its associated disorders. j manipulative physiol ther 2009;32:s227-s243. 23. asenlof a, denison e, lindberg p. individually tailored treatment targeting activity, motor behaviour, and cognition reduces pain-related disability: a randomized controlled trial in patients with musculoskeletal pain. j pain 2005;6:588-600a. 24. stewart mj, maher cg, refshauge km, herbert rd, nicholas mk. patient and clinician treatment preferences do not moderate the effect of exercise treatment in chronic wad. eur j pain 2008;12:879-885. 25. haynes r, devereaux p, guyatt g. physicians’ and patients’ choices in evidence based practice. bmj 2002;324:1350. 26. mercer c, jackson a, moore a. developing clinical guidelines for the physiotherapy management of whiplash associated disorder (wad). international journal of osteopathic medicine 2007;10:50-54. 27. vernon ht, humphreys k, hagino ca. a systematic review of conservative treatments for acute neck pain not due to whiplash. j manipulative physiol ther 2005;28:(6):443-448. 28. oliveira a, gevirtz r, hubbard d. a psycho-educational video used in the emergency department provides effective treatment for whiplash injuries. spine 2006;31:1652-1657. 29. gross ar, goldsmith c, hoving jl, et al. conservative management of mechanical neck disorders: a systematic review. j rheumatol 2007;34(5):1083-1102. 30. macaulay j, cameron m, vaughan, b. the effectiveness of manual therapy for neck pain: a systematic review of the literature. physical therapy reviews 2007;12:261-267. 31. conlin a, bhogal s, sequeira k, teasell r. treatment of whiplash associated disorders part 1: non-invasive interventions. pain res management 2005;10(1):21-32. 32. saborido mc, lizana gf, alcázar ar, sarria-santamera a. effectiveness of spinal manipulation in treating whiplash injuries. aten primaria 2007;39(5):241-246. 33. lamb se, gates s, underwood mr, et al., the mint study team. managing injuries of the neck trial (mint): design of a randomized controlled trial of treatments for whiplash-associated disorders. bmc musculoskeletal disorders 2007;8:7. 34. cooke mw, lamb se, marsh j, dale j. a survey of current consultant practice of treatment of severe ankle sprains in emergency departments in the united kingdom. emerg med j 2003;20:505-507. 35. schellingerhout jm, verhagen ap, heymans mw, et al. which subgroups of patients with non-specific neck pain are more likely to benefit from spinal manipulation therapy, physiotherapy, or usual care? pain 2008;139:670-680. 36. albright j, allman r, bonfiglio rp, et al. philadelphia panel evidencebased clinical practice guidelines on selected rehabilitation interventions for neck pain. phys ther 2001;81(10):1701-1717. 37. haines t, gross ar, burnie s, goldsmith ch, perry lp, graham n. a cochrane review of patient education for neck pain. spine journal 2009;4:1-13. 38. sterling m, pedler a. a neuropathic pain component is common in acute whiplash and associated with a more complex clinical presentation. manual therapy 2009;14:173-179. sajsm vol. 26 no. 1 2014 3 editorial a phase of consolidation before moving forward again it struck me recently that we have entered a consolidation phase in exercise science and sports medicine. the exponential increase in knowledge that we have experienced since the early 1980s seems to have stabilised. this thought came about after the recent publication of excellent reviews on a variety of topics. a key point is that these publications have focused on the translation of the research, emphasising the practical guidelines. these articles have set the standard for best practice. consider as an example the research on concussion. the recent consensus statement[1] is written for healthcare professionals who deal with athletes, and provides tools that can be used to individualise the return-to-play decisions after an athlete is concussed. the document is exhaustive and provides a sports concussion assessment tool (scat3), including one designed for children. there is even a concussion recognition tool (crt) designed for non-professionals. armed with the information provided in this document, a healthcare professional can provide high-level management to an injured athlete, and be guided on the steps for safe return-to-play. the foundations have been laid for universal, good management; this information is in the public domain and is freely available. future research on the management of concussed athletes will be guided by questions arising from the foundation that has been set in this consensus statement. another example of the consolidation of knowledge was published a few weeks ago.[2] this occurred in the important area of managing players’ wellbeing, in particular the management of their health, risk of injury and training status. this article was written by paul dijksra,[2] a south african who studied medicine at the university of pretoria and sports medicine at the university of cape town. he was the chief medical officer of uk athletics and is currently working in qatar as the assistant chief of sports medicine for the qatar sports medicine department. this article describes a framework designed for the continuous monitoring and management of the health and performance of athletes. the structured approach assists with decisionmaking about training and competing, especially while the athlete is ill or injured. the integrated performance health management and coaching model considers the best medical advice and individualised needs of the athlete. as with the concussion consensus document, this article is rich in theoretical, supportive information, which is translated into systematic, clear guidelines for practitioners. anyone entering the field can use this as a blueprint, comforted by the fact that they are providing a high level of service if they implement the guidelines. documents such as these may create the impression to a newcomer to the field of exercise science and sports medicine that all the ques tions have been answered. nothing could be further from the truth. there is still much work to be done, and there are many more questions to answer. as our collective knowledge evolves, the questions subjected to research merely become more specific and focused, either in striving to understand the mechanisms of action, or in trying to determine the efficacy of the intervention. there will always be a need to offer services to athletes that reduce the risk of injury, ensure health and wellbeing, while increasing the chances of the athlete peaking at the right time. while the latest articles translating theory into practice show that we have made excellent progress in the last 30 years, there will always be questions that need to be answered to enable these services to be optimised and fine-tuned. this edition of the journal, the first in 2014, showcases south african research on musculoskeletal injuries in female adolescent hockey players,[3] collagen gene interactions and endurance running performance,[4] and the feasibility of pedometer based-health promotion. [5] there is also a study,[6] submitted by researchers in the uk, in which goal expectations and performance in time trials between successful and unsuccessful cyclists were assessed. a reminder that the south african sports medicine association (sasma) represents several disciplines and this journal, being the mouthpiece of sasma, has to reflect this. readers are encouraged to submit original research, case studies or commentaries. guidelines for the format of the article submissions are available online at http://www.sajsm.org.za. mike lambert editor-in-chief 1. mccrory p, meeuwisse wh, aubry m, et al. consensus statement on concussion in sport: the 4th international conference on concussion in sport held in zurich, november 2012. br j sports med 2013;47(5):250-258. 2. dijkstra hp, pollock n, chakraverty r, alonso jm. managing the health of the elite athlete: a new integrated performance health management and coaching model. br j sports med 2014;48(7):523-531. 3. ellapen tj, bowyer k, van heerden hj. common acute and chronic musculoskeletal injuries among female adolescent field hockey players in kwazulu-natal, south africa. south african journal of sports medicine 2014;26(1):4-8. [http://dx.doi. org/10.7196/sajsm.482] 4. o’connell k, posthumus m, collins m. collagen gene interactions and endurance running performance. south african journal of sports medicine 2014;26(1):9-14. [http://dx.doi.org/10.7196/sajsm.523] 5. pillay jd, kolbe-alexander tl, proper ki, van mechelen w, lambert ev. steps that count! a feasibility study of a pedometer-based, health-promotion intervention in an employed, south african population. south african journal of sports medicine 2014;26(1):15-19. [http://dx.doi.org/10.7196/sajsm.500] 6. rhoden c, west j, renfree a, corbett m, st clair gibson a. micro-oscillations in positive and negative affect during competitive laboratory cycle time trials – a preliminary study. south african journal of sports medicine 2014;26(1):20-25. [http://dx.doi.org/10.7196/sajsm.496] s afr j sm 2014;26(1):3. doi:10.7196/sajsm.538 http://www.sajsm.org.za http://dx.doi.org/10.7196/sajsm.482] http://dx.doi.org/10.7196/sajsm.482] http://dx.doi.org/10.7196/sajsm.523] http://dx.doi.org/10.7196/sajsm.500] http://dx.doi.org/10.7196/sajsm.496] sajsm 473.indd review sajsm vol. 25 no. 3 2013 87 cricket is played in three formats at elite level: test, one day and twenty20. fielding is an important component of cricket, as all players are obliged to �eld. however, there is a paucity of literature on �elding compared with that on batting and bowling. we review the available literature in terms of technical, mental, physiological and physical factors important to �elding, to identify knowledge gaps and better understand the performance requirements of �elding in cricket. s afr j sm 2013;25(3):87-92. doi:10.7196/sajsm.473 a review of cricket �elding requirements d macdonald,1,2 msc; j cronin,1,2,3 phd; j mills,2 grad dip; m mcguigan,1,3 phd; r stretch,4 dphil 1 sport performance research institute, aut university, auckland, new zealand 2 new zealand cricket, christchurch, new zealand 3 school of exercise and health sciences, edith cowan university, perth, australia 4 nelson mandela metropolitan university, port elizabeth, south africa corresponding author: d macdonald (dani.macdonald@aut.ac.nz) internationally, three formats of cricket are played at the elite level: test, one day and twenty20.[1] all players bat and field, while only some players bowl and one person keeps wicket. dismissing a batsman can be achieved in different ways, some specific to fielders; hence, catching and throwing are vital skills. common requirements for these skills are speed and accuracy.[2] as well as dismissing batsmen, the role of �elders includes saving runs, particularly in the shorter formats of the game. therefore, optimising the movements and skills required to successfully field can have an important influence on the game. however, despite the adage that ‘catches win matches’, research into �elding is sparse compared with that into batting and bowling.[3] �e purpose of this review was therefore to investigate and critique the existing knowledge of fielding in cricket, with the intent of better understanding the performance demands of �elding. methods for the purpose of this review, fielding performance was divided into a number of components (fig. 1) which were systematically reviewed. reviewed literature included peerreviewed articles and book chapters. the requirements of the wicket-keeper are not discussed here, as the demands of this position have been reviewed previously.[4] the literature search was conducted using search engines (pubmed, sportsdiscus and sciencedirect). the search terms 'fielding', 'wicket-keeping', 'catching', 'cricket' and other related terms were used in various combinations to search for articles. the reference lists of articles found were assessed to extend the search. as �elding was the focus of this review, articles speci�cally focusing on the wicket-keeper were excluded from the review. additionally, cricket-relevant chapters from edited books were included. technical in cricket, the playing field is not of fixed dimen sions. according to the laws of the game, ‘the playing area shall be a minimum of 150 yards (137.16 m) from boundary to boundary square of the pitch, with the shorter of the two square boundaries being a minimum of 70 yards (64.01 m)’.[5] due to the large and varying size of the playing �eld, the skills of �elding in cricket will vary considerably depending on where �elders are placed. here, the �elding positions have been categorised as close (e.g. slips and short leg), inner-circle and outer-circle (fig. 2). shilbury[6] researched the frequency of field ing skills for 25 defined positions, and the �elding patterns of individual players of an ‘a’-grade cricket team playing first-class multi-day cricket. �e data were divided into four skill categories: �elded ball, �elded ball and throw, �elded ball and under-arm return, and catches and attempted catches. �e author reported the frequency and skills required in 25 fielding positions. the positions which featured the most were cover (12%), mid-o� (10%) and mid-on (9%), respectively. cover has traditionally been considered a position that requires good attacking skills, such as being able to move towards the ball, �eld and throw quickly, o�en from unbalanced positions.[6] however, only 13% of cover’s �elding contacts required attacking skills; the majority of actions were defensive fielding and wicket-keeping performance technical mental physiological physical fig. 1. aspects of �elding performance. and required practically no diving or lateral movements. this finding is not consistent with conventional wisdom. shilbur y’s study is dated (1990), and included data from only six domestic games. given the developments in the game since the 1990s, research based on a larger number of international matches would be more appropriate and useful. � ese � ndings will assist the development of assessment and training protocols for the di� erent formats of the game at the highest level. in one day cricket, matches began to be played into the night, and the ball colour was changed from red to white to be seen better under � oodlights. scott et al.[7] investigated the e� ect of light levels and ball colour on catching, particularly for slip fielders in simulated field conditions. photoelectric timing gates were placed in front of a ball projection machine and lever micro-switches were placed on the thighs of the players to establish reaction times to balls projected at a speed of 20 m/s over a distance of 8.4 m. � e speed was considered representative of the demands of slip-catching performance, and was the upper limit of speeds safe for use under laboratory conditions. catching performance was scored using a scale adapted from wickstrom,[8] which rated catches from 0 (no ball contact at all) to 5 (clean catch). a� er performing a 2 (ball) × 3 (light level) analysis of variance (anova), no signi� cant e� ects were noted for catching performance and movement initiation times for ball or light levels. � e authors concluded that the change in ball colour or diminishing light levels were not detrimental to performance. however, the sample size was very small (n=5), which might have accounted for the lack of statistical signi� cance. also, the testing protocol required players to assume a standing position that may not be normal under game conditions. � e e� ect of a visual-perceptual training programme on � elding in cricket has been investigated using a test-retest design involving a 6-week training intervention.[9] � e tests involved an in situ � elding test, and athletes were required to react (predict and move in the direction that the ball was hit) to a life-sized video projection of a batsman hitting strokes, with the video occluded at the point of ball contact. � e video was � lmed from the perspective of 3 di� erent � elding positions: extra cover, mid on and mid o� . moving in the correct direction for each video assessed decision accuracy. � e training group underwent an add itional 3 perceptual training sessions per week in addition to the on-� eld training programme undertaken by the control group. � e training group performed significantly better than the control group in the two tests. it was concluded that while 6 weeks of regular on� eld training may lead to improvements in fielding performance, greater advantages could be gained when this is combined with visual perceptual training sessions. a fielder‘s ability to throw a ball over considerable distance with speed and accuracy, if aiming for a run out, requires excellent throwing technique.[10] the requirements are speci� c for the di� erent � eld positions. � e slips mostly intercept a fast moving ball coming o� the edge of the bat and reaching them below chest height.[11] � ey have little need for throwing long distances. in-� elders require good reactive ability to catch a ball falling from above their heads and strong overarm throwing ability[3] to attempt run-outs. out� elders o� en have to cover a considerable distance, so sprinting ability is vital, and they need to throw accurately over long distances. [6] good techniques are not only essential to win matches; they also minimise the risk of injury. [2] synchronised high-speed video cameras[11] have been used to study the biomechanics of throwing. distinguishing di� erent throwing techniques has led to the identification of important performance variables.[11] the relationship between over-arm throwing velocity and accuracy in elite and sub-elite cricketers was investigated using a speci� cally designed throwing test.[8] a speed-accuracy trade-off was detected. subjects improved accuracy scores at velocities of 75 85% of maximal throwing velocity. s enior elite players performed better than other groups. no research into sideor underarm throwing in cricket has been found. using the correct technique is crucial for success; the lack of empirical data in this area limits the development of optimal training programmes. 88 sajsm vol. 25 no. 3 2013 fig. 2. pitch map showing the di� erent � elding categories. (wk = wicket keeper.) third man fine leg gully slips wk short leg leg gully cover point cover extra cover mid-o� mid-on mid-wicket point square leg long-o� long-on sajsm vol. 25 no. 3 2013 89 for skills development, player selection and talent identi�cation, it is important to test correctly for skill and movement e�cacy. �is can assist a coach to detect strengths and weaknesses in performance and to identify the speci�c training needs of the individual.[12] stretch and goslin[12] devised a set of cricket skills tests, encompassing all components of the game. with regards to �elding, the majority of runouts occur between 10 m and 35 m,[13] and these were the distances tested in the �elding test (fig. 3). at point a, the �elder was required to catch a thrown ball, over-arm throw at the target and then move as quickly as possible to point b. at points b, c, d, e, and f, the �elder was required to pick a ball up from the ground and over-arm throw at the target; point g required a pick up and under-arm throw at the target, followed by a �nal sprint to the target. �e timer started when the �elder touched the �rst ball and ended when he had run through the target. a time penalty (3 s) was given if he dropped the balls or a throw did not go through the target at any time during the test. �e authors and coaches also used their knowledge of the game to determine, sub jectively, the players’ potential success in a match.[12] �e validity of the �elding tests was tested by comparing the objective tests to the subjective opinion of coaches. �e relationship between the objective �elding test scores and the subjective �elding evaluation was low (r=0.47; p<0.05); however, the sample size was relatively large (n=155), hence the authors decided that the lower correlation was acceptable. �e diagnostic utility of this test could be questioned, given the composite nature of the test i.e. many skills assessed within one test. mental cricket requires inordinate physical skill and mental aptitude, including the ability to concentrate intensely for very long periods, for which a high level of physical �tness cannot fully compensate.[14] fielders have to concentrate on every ball of the innings, regardless of their positions. �ey have to be able to maintain concentration for the entire duration of an innings (ranging from approximately 90 minutes in a t20 innings to a total of 6 hours per day in a test match), through changing conditions as play progresses through the day. however, studies on the mental aspect of cricket have focused on batting only;[15-17] no research, to the authors’ knowledge, has addressed the mental aspects of �elding. physiological �e most prevalent approach to quantifying the physiological demands of cricket is time-motion analysis using global position ing satellite (gps) units. rudkin and o’donoghue[18] performed 27 observations of a �elder positioned at cover point, during �rst-class multi-day games. �ey used the captain time-motion analysis system to de�ne seven movement classes: stationary, walking, shu�ing (rapid non-running movement of the feet), jogging, running, low-intensity fielding and high-intensity �elding. it was found that the cover point �elder spends the majority (94.2%; standard deviation (sd) ±2.4) of match time in stationary activity and walking, while high-intensity activities represented just 1.6% (sd ±0.8) of movement activity. it was concluded that �rst-class �elding entails less high-intensity exercise than other team sports such as hockey and soccer. however, the conclusions are of limited value, as only one �elding position was analysed. time-motion studies could help develop knowledge of positional di�erences in work load between the di�erent formats of cricket, allowing conditioning coaches to prescribe game-speci�c training programmes. [1] petersen et al.[1,19,20] have conducted several studies using gps technology, investigating physiological demands of performance in the three di�erent formats of the game. unlike in the study by rudkin and o’donoghue,[18] �ve movement categories were established (standing/walking, jogging, running, striding and sprinting) and the three di�erent cricket formats were investigated. table 1 summarises time-motion analyses for each format of cricket. in summary, it seems that �elding intensity is greatest in a t20 match and �elders covered approximately the same distances in one day and test cricket. petersen et al.[19] tested the validity and reliability of three commercially available sports gps units to monitor cricket-speci�c movement patterns. �ey found disparate and inconsistent measures for the validity and reliability of lowand high-intensity activities. �ey advised that conditioning coaches should be aware of the likely under-reporting of high-intensity activity and over-reporting of lowintensity e�orts when using gpss in training. all studies detailed thus far fail to document the physiological demands of the di�erent �elding positions because, generally, �elders – without distinction – are compared with bowlers and batsmen. physical �e physical aspects of performance have been investigated with respect to injury incidence and prevention, particularly for fast bowling and throwing, but little investigation into the physical aspects of �elding fig. 3. schematic of the �elding test used by stretch and goslin.[12] e f 5 m 10 m a g 10 m 0.71 m b c d 10 m 10 m 10 m 90 sajsm vol. 25 no. 3 2013 has taken place. in this section, physical aspects such as anthropometry, strength, speed and aerobic and anaerobic �tness will be considered. anthropometry several studies have investigated the anthropometric pro�le of �rstclass cricketers,[21-25] mostly by comparing groups of players, such as batsmen, bowlers or all-rounders. �e measures used mass and stature measurement and the sum of seven skin folds (biceps, triceps, subscapular, supra-iliac, abdominal, thigh and medial calf ). portus et al.[25] extensively researched the characteristics of australian players. however, these �ndings are probably not valid globally given ethnic differences in stature. while other physical attributes would be considered when deciding where to place players in the �eld, certain anthropometric characteristics may make players suited to speci�c positions. nevertheless, the anthropometry for specific fielding positions has not been explored. aerobic and anaerobic �tness with modern cricket, players can be expected to tour for up to eleven months of the year; therefore, physical �tness is increasingly important. the only study[26] that focused specifically on the calori�c energy demand of cricketers was performed in 1955, and its validity in representing the demands of modern players would seem problematic. more recent research has indicated that cricketers generally rely on aerobic energy supply and that the rates of energy expenditure of cricket are relatively low; with the exception to this being fast bowlers during a bowling spell[21,26] and �elders sprinting a�er the ball. �is generalisation is supported by the �ndings of time-motion analyses.[1,19,27] �e multi-stage �tness test is recommended to test aerobic power as it is inexpensive, easy to administer and applicable to many team sports with respect to the stop, start and change-of-direction movement patterns.[24] one study[14] showed that cricketers had a higher shuttle run number when compared with rugby union players, with a vo2max of ~60 ml/kg/min. johnstone and ford[21] established physical fitness profiles of cricketers grouped into bowlers and batsmen (n=15) using this test. �e authors recorded the number of completed shuttles (12.4; sd ±0.9), end heart rate (190.4 bpm; sd ±11.2) and predicted the vo2max (54.9±3.7). �e researchers table 1. summary of �ndings from time-motion studies by petersen et al.[19,20] variable* study quantifying positional movement patterns in twenty20 cricket[19] comparison of player movement patterns between odi and test cricket[20] odi test position fielders (n=14) fielders (n=17) fielders (n=25) distance per hour (m) walking (0 2.0 m/s) 3 286 (±726) 2 419 (±708) 2 263 (±629) jogging (2.0 3.5 m/s) 1 532 (±361) 616 (±272) 621 (±135) running (3.5 4.0 m/s) 377 (±156) 147 (±62) 137 (±44) striding (4.0 5.0 m/s) 497 (±316) 159 (±89) 166 (±62) sprinting (≥5 m/s) 416 (±265) 90 (±73) 155 (±71) total distance (m) 6 106 (±981) 3 430 (±883) 3 342 (±759) time (s) walking and jogging 3 263 (±187) 3 504 (±46) 3 496 (±30) running, striding and sprinting 275 (±146) 91 (±45) 104 (±30) sprint number 23 (±14) 6 (±4) 8 (±4) mean sprint distance (m) 17 (±4) 15 (±4) 18 (±5) maximum sprint distance (m) 54 (±23) 34 (±12) 43 (±15) maximum sprinting speed (m/s) 8.6 (±1.1) 7.9 (±1.2) 8.5 (±0.9) high-intensity e�orts number 98 (±43) 34 (±17) 34 (±11) e�ort duration 2.8 (±0.4) 2.6 (±0.3) 3.1 (±0.3) recovery between (s) 45 (±21) 134 (±73) 116 (±37) odi = one day international; sd = standard deviation. * values are expressed as mean (±sd). sajsm vol. 25 no. 3 2013 91 concluded that the vo2max results of cricketers were superior to that of the general population.[21] �ese results are comparable with the normative data presented for cricket players in physiological tests for elite athletes.[25] anaerobic �tness has generally been tested using repeated sprint tests. johnstone and ford[21] found that the running speed for each of the groups was similar, although the bowlers achieved moderately better results (1.5%) in maximal repeated sprint tests than the batsmen. sprint tests in cricket have typically varied in distance (10 40 m); therefore, it is di�cult to compare results between studies. johnstone and ford[21] recommended that the future assessment of cricket-speci�c speed should use short distances of 5 15 m, because these may be associated with higher levels of match-winning �elding performance. however, sprint testing over a large range of distances may be justi�ed because the size of the pitch that players will have to cover varies in distance depending on �elding position. in summary, cricket players require a high level of aerobic �tness in order to play for up to 6 hours per day, with intermittent, short bursts of high-intensity e�ort that requires contribution from the anaerobic energy system. whether these demands di�er as a function of �elding position has not been researched. it may be that a position such as slips with potentially less aerobic demands may bene�t from greater doses of high-intensity reactive training. nevertheless, given the length of the international cricket season and the tour demands of cricketers, superior aerobic �tness will assist players in recovery and sustaining performance at the highest level. strength, power and speed upper body �e results of studies on strength and power pro�les of cricketers have, thus far, been ambiguous and seem to lack logical or face validity. johnstone and ford,[21] for example, measured upper-body strength and power using a medicine ball throw and timed press-up tests. �ere were marked di�erences between batsmen and bowlers; the batsmen were superior in the timed press-up tests, but the bowlers produced greater backward throws. however, the signi�cance of these results and their relation to performance is unclear. �ere is no research on speci�c �elding positional demands, nor have normative data for each �elding position been established. nevertheless, it appears that di�erent strength requirements may be needed for di�erent �elding positions (e.g. the throwing demands of an out�elder v. a slip �elder). lower body leg strength and power are important for cricket �elders as they contribute to the speed and agility required for �elding. however, there has been little research on the lower-body strength pro�le of cricketers. johnstone and ford[21] tested lower-body strength and explosive power using a counter-movement jump and repeated vertical jump test. �e authors suggested that tests such as the counter-movement jump give an indication of slow stretchshortening cycle performance, and found that there were negligible di�erences between bowlers and batsmen. bourdon et al.[24] also recommended a series of tests for pro�ling the physical �tness of elite cricketers; the lower-body tests included a vertical double-leg jump, abdominal strength stage test, straight sprint speed (10, 20 and 40 m) and a run 3 agility test. while the abdominal stage test is lauded as particularly important for fast bowlers, the authors noted that batsmen and fielders would benefit from good abdominal strength during long periods in the �eld or at the batting crease. �e leg-power demands of �elding are little understood; however, a study comparing cricketers with rugby players found no signi�cant di�erences in leg press, bench press and 35 m sprints.[14] for example, there is little logic in using only a vertical jump test when research and observation show that �elders need to move in all directions and consequently need multi-directional lower-leg strength and power. correctly assessing the multi-planar movement ability of �elders should lead to better training programmes. conclusion there is a paucity of scientific information on the performance demands of �elding across all the areas of interest discussed in this review article, i.e. technical, physical, etc. �ere seems to be little appreciation of the technical requirements related to di�erent �elding positions. from the scant literature available, it is possible to deduce that cricket �elding is, in general, a low-intensity activity that requires intermittent bursts of explosive movement. however, conventional wisdom on several aspects of the game is not supported by scienti�c evidence. given that �elding is an essential component to winning matches, the lack of research in this area is disconcerting. a systematic research programme covering all components of all game formats would be bene�cial. existing knowledge could be complemented by obtaining the considered opinions and insights of coaches and players and by carrying out detailed video and notational analyses. �e results would provide greater insight into the skill and movement requirements associated with the di�erent �eld positions. �is information would also provide a framework for the design of �elding-speci�c assessments, which should enable the development of more focused training, conditioning and coaching protocols. �is should enhance �elding performance and contribute to the ultimate goal of winning matches. references 1. petersen c, pyne d, dawson b, portus m, kellett a. movement patterns in cricket vary by both position and game format. j sports sci 2010;28(1):45-52. 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[http://dx.doi.org/10.1519/jsc.0b013e3181bac3a7] 22. stretch ra. anthropometric pro�le and body composition changes in �rst-class cricketers. s afr j res sport phys educ recreation 1991;14(2):57-64. 23. stretch ra. anthropometric pro�le of �rst-class cricketers. s afr j res sport phys educ recreation 1987;10(1):65-75. 24. bourdon p, savage b, done r. protocols for the physiological assessment of cricket players. in: gore cj, ed. physiological tests for elite athletes. champaign, usa: human kinetics, 2000:238-243. 25. portus m, kellett a, karppinen s, timms s. cricket players. in: tanner rk, gore cj, eds. physiological tests for elite athletes. 2nd ed. torrens park: human kinetics, 2013. 26. fletcher jg. calories and cricket. lancet 1955;1:1165-1166. 27. petersen c, pyne d, portus m, dawson b. quantifying positional movement patterns in twenty20 cricket. int j perform anal sport 2009;9:165-170. the problem chronic diseases pose both a humanitarian and economic problem to a country. while the prevalence of these diseases (coronary heart disease, obesity, type 2 diabetes, etc.) is not well documented in africa, their meteoric rise is well publicised in the usa. it has been estimated 1 that chronic diseases affect 90 million americans and cost up to $1 trillion in health care and lost production costs. physical inactivity – defined as less than 30 minutes of activity per week – is often referred to as a modifiable risk of chronic disease. in fact, 28% of preventable deaths alone in 1993 were attributed to physical inactivity or factors in the diet. 1 but just how and why is physical inactivity such a potent risk factor for disease? booth et al. 1 return to early man and investigate evolutionary trends to develop their hypothesis. while our genotype has not changed much since the late paleolithic era, our phenotype has been significantly altered by various ‘advancements’ in lifestyle. early man’s survival was based on an ability to subsist from the land, and was thus dependent on an appropriate phenotype for this function. it has been estimated that on average the energy expenditure of people living in contemporary society is only about 65% of the energy expenditure of the hominids from the late paleolithic era. this translates into a mismatch for the level of physical activity coded for by our genome. furthermore, by delving into early man’s patterns of nutrition, it appears that cycling periods of food availability programmed the body to respond to physical inactivity in a particular way. 1 periods of inactivity were associated with times of famine, and as a result insulin resistance and atrophy are thought to occur in skeletal muscle as potential survival mechanisms for humans. as a corollary, the rapid conversion of excess calories into adipose tissue during ‘feast’ times is thought to have been pre-programmed to prepare for periods of ‘famine’. if early man is to rural dwellers (non-migrants) what contemporary man is to urban migrants, this hypothesis gains support in a study of guatemalan adults. 2 not surprisingly, migration into an urban setting was associated with a significant decrease in physical activity. the migrants also tended to consume more fats overall and exhibited a relative increase in weight in comparison to their rural counterparts. the reduction in physical activity observed in urban settlers is multifactorial. jobs are less labour intensive, amenities easier to access, and infrastructure and technologies more advanced in city settings, resulting in a decreased requirement for physical activity in urban dwellers. 2,3 in fact, sedentarism has been recorded at levels as high as 80% in certain developed countries. 4 while physical inactivity is not the only cause of chronic diseases, it certainly is the most modifiable of all risk factors. booth et al. 1 conclude: ‘we know of no single intervention with greater promise than physical exercise to reduce the risk of virtually all chronic diseases’. the solution although united under the associative banner of the health professions council of south africa (hpcsa), sports medicine and its allied health professionals are not yet one unified ‘family’. therefore it would be difficult to organise a public health outreach with such diverse medical roles and opinions. this is, of course, without mentioning the same diversity of opinions present in political and municipal bodies. therefore, the aid of government, non-governmental organisations and other entities would be required to drive such an outreach programme. this is especially true with regard to resources and the dissemination of a clear, simple, yet effective message. 5 the agita são paulo programme is an example of an effective education programme which attempted to educate the 34 million mega-populated são paulo state of brazil on the benefits of physical activity. 6 a population of 34 752 225 people, in an area slightly smaller than the uk, comprising 645 municipalities, was targeted. a scheme using an eight-pillar base was implemented to achieve the objectives of the programme. heading up the process for change was a research centre (pillar 1) – this was run by academic personnel from over 160 scientific and institutional partnerships (pillar 2). by using the academic assets afforded by pillar 2, a feasible ‘one-stepahead’ model (pillar 3) was designed. this model developed specific messages that targeted individuals in the cycle of activity; the sedentary to become active, the moderately active to become more active, and the regularly active to maintain activity levels without injury. empowerment (pillar 4) saw the encouragement of existing programmes, giving all of these programmes a common flag under which to unite. inclusion (pillar 5) saw the replacement of traditional jargon such as ‘sport’ and ‘fitness’ by more effective phrases such as ‘active living’ and ‘physical activity for health’. for effective exposure, a ‘non-paid media’ approach was taken (pillar 6) which made use of local newspapers and radio stations. pillar 7 was that of social commentary the cost of physical inactivity to a nation: the role of sports medicine and its allied health professionals in preventing a crisis correspondence: james brown uct/mrc research unit for exercise science and sports medicine sports science institute of south africa newlands 7700 e-mail: james.brown@uct.ac.za james brown (bsc (med) (hons) exercise science) joshua mervyn smith (bsc (med) (hons) exercise science – biokinetics, nsca-cpt) uct/mrc research unit for exercise science and sports medicine, department of human biology, university of cape town 102 sajsm vol 21 no. 3 2009 marketing, and involved various ‘agita days’ or ‘active days’. the benefit of these days was twofold: ‘agita programme’ exposure and an opportunity for the public to experience the programme’s concepts practically. the final pillar (pillar 8) was that of ‘culture links’, and incorporated the important brazilian concept of having fun at all times. 6 the efficacy of the agita são paulo programme is its greatest success, having educated 56% of the population that were originally targeted. 6 of the sample that were educated by the programme, 55% of individuals met the activity recommendation of the programme. furthermore, only 7% of the people that were educated were classified as sedentary in comparison with the 13% of those who were unaware of the programme. the agita são paulo programme has been accepted as an effective model by the world health organization. sports medicine and its allied health professionals need to collaborate with government and its municipalities if we are to drive an effective south african public health initiative as occurred in brazil. the agita são paulo programme is a fine example of how this scientific and medical collaboration can avert a national crisis at the hands of a chronic disease scourge. references 1. booth fw, gordon se, carlson cj, hamilton mt. waging war on modern chronic diseases: primary prevention through exercise biology. j appl physiol 2000;88(2):774-787. 2. torun b, stein ad, schroeder d, et al. rural-to-urban migration and cardiovascular disease risk factors in young guatemalan adults. int j epidemiol 2002;31(1):218-226. 3. hamilton mt, hamilton dg, zderic tw. role of low energy expenditure and sitting in obesity, metabolic syndrome, type 2 diabetes, and cardiovascular disease. diabetes 2007;56(11):2655-2667. 4. bernstein ms, morabia a, sloutskis d. definition and prevalence of sedentarism in an urban population. am j public health 1999;89(6):862-867. 5. matsudo sm, matsudo vr, araujo tl, et al. the agita são paulo program as a model for using physical activity to promote health. rev panam salud publica 2003;14(4):265-272. 6. matsudo v, matsudo s, andrade d, et al. promotion of physical activity in a developing country: the agita são paulo experience. public health nutr 2002;5(1a):253-261. sajsm vol 21 no. 3 2009 103 case report 1 sajsm vol. 34 no.1 2022 creative commons attribution 4.0 (cc by 4.0) international license myositis ossificans in a child athlete: a case study r sapire,1,2 ; r nenova,1,2 ; p gounder,1,2 bhsc; a rampersad,1,2 ; v maboho1,2 bhsc; n nhlapo,1,2 ; k tibatshi,1,2 bsc; s rampurtab,1,2 ; ai ranchod,2,3 fc rad (d); rt saggers,2,4 mmed, fc paed; j patricios,2,5 facsm, ffsem (uk) 1 unit for undergraduate medical education, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 wits sport and health (wish), school of clinical medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 3 department of diagnostic radiology, university of the witwatersrand, johannesburg, south africa. 4 department of paediatrics and child health, charlotte maxeke johannesburg academic hospital and school of clinical medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 5 netcare waterfall sports orthopaedic surgery, johannesburg, south africa corresponding author: rt saggers (robin.saggers@wits.ac.za) case report myositis ossificans (mo) is a rare pathological disorder characterised by the accretion of nonneoplastic bone in skeletal muscle and surrounding soft tissue.[1] three types have been classified: hereditary mo (mo progressiva, a rare autosomal dominant condition), non-traumatic mo (associated with burns, haemophilia and neurological conditions) and traumatic mo (mo circumscripta, associated with direct or repetitive trauma). traumatic mo is the most common – occurring in approximately 60-75% of cases – and is often secondary to sports-related impacts.[2] following traumatic incidents, the lesion arises from an inflammatory reaction that causes endothelial to mesenchyme transition (endmt) in vascular endothelial cells. the cells differentiate into chondrocytes, which then undergo endochondral bone formation or osteoblasts directly resulting in localised ossification.[1] mo usually presents as a warm, tender swelling with overlying erythema and progresses to a palpable osseous mass with maturation. symptoms include joint and muscle stiffness, pain on movement and a decreased range of motion. commonly affected sites are the arm flexor and thigh extensor muscles.[1] mo is rare in young children, occurring mostly in adolescents and young adults. on examination and radiological assessment, early mo presents with similar patterns to that of an osteosarcoma.[3] treatment modalities range from conservative therapies, such as rest, ice and elevation, with concurrent use of nonsteroidal anti-inflammatories, radiotherapy, extracorporeal shock-wave therapy and acetic acid phonophoresis to more aggressive surgical approaches, which are usually only considered after 6 – 12 months of unsuccessful conservative therapy.[3] history a 13-year-old female developed a large painful lesion in her right buttock. pain radiated from the lesion to the posterior thigh and worsened at night, with no associated constitutional symptoms. the patient had been unable to participate in her usual sporting activities (namely, horse riding, hockey and tennis) and was receiving physiotherapy for the pain which was unresponsive to therapy. she had no recollection of trauma directly related to the site of the lesion. physical examination on general examination, the patient was healthy but in some discomfort upon sitting. on localised examination, there was a tender, palpable, golf ball-like mass in her right gluteal muscle with overlying erythema. investigations ultrasonography demonstrated a hypoechoic heterogeneous mass (70 x 45 x 35mm) in the proximal third of the right gluteus maximus muscle belly. within this mass, there were areas that resembled the typical appearance for proliferative myositis. however, there was a solid more hypoechoic mass (35 x 25 x 33mm) which demonstrated two calcifications background: a 13-year-old female athlete presented with a painful lesion in her right buttock for which she had been receiving physiotherapy. it was keeping her from participating in sports. aim: to report on a case of traumatic myositis ossificans in a child athlete – including the presentation, investigations, management, and outcome. findings: palpation of the right buttock indicated a tender mass. investigation by musculoskeletal ultrasound detected a large hypoechoic lesion. an mri revealed patterns of calcification that were inconclusive in differentiating between a malignant or benign lesion. macroscopic and microscopic histological examination, as well as immunohistochemistry, were consistent with myositis ossificans (mo), a non-malignant condition. the patient improved remarkably within three months of treatment with rest, non-steroidal anti-inflammatory drugs (nsaids) and extracorporeal shock wave therapy (eswt). implications: accurate differentiation of myositis ossificans from other benign and malignant soft tissue lesions may require histological evaluation in addition to a comprehensive radiological workup. successful treatment with the patient being able to return to a pain-free and active state is achievable. extracorporeal shock-wave therapy can play an important role in the management of this condition and should be considered when presented with a case of mo. keywords: traumatic, benign, malignant, extracorporeal shock-wave therapy, osteosarcoma s afr j sports med 2022; 34:1-4. doi: 10.17159/2078-516x/2022/v34i1a14931 http://dx.doi.org/10.17159/2078-516x/2022/v34i1a14931 https://orcid.org/0000-0002-1056-7065 https://orcid.org/0000-0003-2001-5659 https://orcid.org/0000-0001-5546-7650 https://orcid.org/0000-0002-3257-5998 https://orcid.org/0000-0001-6593-8049 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0001-9995-6261 https://orcid.org/0000-0002-8434-8025 https://orcid.org/0000-0001-6883-1378 https://orcid.org/0000-0002-1678-8600 case report sajsm vol.34 no.1 2022 2 within the deep part of the larger mass identified. the muscle architecture, superficial and deep, appeared normal. a colour doppler ultrasound showed mildly increased vascularity within the mass and peripherally (see figure 1). magnetic resonance imaging (mri) was indicated, as a malignant soft tissue lesion could not be excluded by ultrasound. a multiparametric preand post-contrast 1.5t mri scan of the pelvis was obtained five days after presentation. there was a heterogeneously enhancing mass with thin peripheral calcification within the right gluteus maximus, with significant surrounding oedema (see figure 2). these findings favoured the intermediate phase of mo as the primary differential diagnosis but could not definitively exclude malignancies, along with lymphoma, osteosarcoma and rhabdomyosarcoma.[4] x-ray findings of the pelvis were suggestive of early rim ossification that occurs in a progressive mo lesion. the blood results from the day of presentation showed normal red cell indices, normal absolute leukocyte values and moderate thrombocytosis. c-reactive protein, creatinine kinase and renal function were normal. histology due to the uncertainty of the diagnosis and potential risk of a malignant lesion, the patient was referred to an orthopaedic surgeon with a specific interest in soft tissue lesions. a biopsy was taken and sent for histological evaluation. macroscopic examination showed three gritty soft tissue fragments, with the largest fragment measuring 15 x 5 x 3mm. immunohistochemistry on a population of spindle cells was performed. the immunoprofile, consisting of a moderate proliferation index and a positive smooth muscle actin marker, was compatible with the myofibroblastic nature of the proliferating cells and consistent with mo. microscopic examination of the paraffin sections showed subcutaneous fibroadipose connective tissue, skeletal muscle and an area of new bone formation in conjunction with a cellular spindle cell proliferation. the spindle cells exhibited a fibroblastic appearance. the peripheral bony trabeculae appeared relatively mature with clear osteoblastic rimming and orderly maturation. there was an impression of zonation within the lesion. occasional normal mitotic figures were seen in the specimen. these findings were consistent with the reactive process seen in mo. there was no histological evidence of malignancy. diagnosis of mo was then confirmed. management following the diagnosis of mo, further interrogation of the patient’s history led to her revealing that she rode horses and had fallen three months before presentation, possibly on to her buttock. she was advised to stop physiotherapy and all sporting activities to prevent exacerbation. the lesion was monitored for changes. a central sensitivity inventory (csi) self-report was used to quantify pain hypersensitivity. oral indomethacin of 75mg daily was administered to reduce pain, stiffness and inflammation. a ring cushion was recommended fig. 1. doppler ultrasound mass (70 x 45 x 35mm) identified within the right gluteus musculature. mildly increased vascularity seen within the mass and at the periphery. possible calcifications seen within the lesion. fig. 2. axial mri pelvis – significant surrounding oedema (arrowheads), extending laterally to the greater trochanter and medially into the sciatic notch. a rim of hypointense calcifications (arrows) seen at the periphery of the lesion. axial measurement is 3.4 x 2.5cm. fig. 3. x-ray pelvis – typical peripheral ossification of the mature lesion (arrows). case report 3 sajsm vol. 34 no.1 2022 to alleviate pressure to the area when sitting. once tenderness had improved, extracorporeal shock-wave therapy (eswt), under local anaesthesia, was performed on three occasions. discharge and return to all activities and sports was granted three weeks after initial eswt. follow-up imaging after initiation of treatment the patient was followed up clinically and with imaging. after two months, xrays remained unchanged, indicating stability of the lesion. four months later, oblique x-ray imaging confirmed ossification and a slight reduction in size of the lesion (see figure 3). a follow-up mri six months after diagnosis showed resolution of the surrounding oedema. the central lesion remained but with an increased rim of calcification and fat-based tissue (likely representing marrow fat related to developing ossification) immediately adjacent to the calcification (see figure 4 and figure 5). the lesion was slightly smaller in size compared to previous measurements (see figure 2). furthermore, there was no fluid in the sacroiliac joints, and no other abnormalities within the hip joint and bursae. these mri findings corresponded with the evolution of the lesion from the subacute or intermediate phase to the chronic phase. outcome two months after the initiation of treatment, the patient’s discomfort with walking and night pains had lessened. she was able to resume low-intensity exercise, hop on the right leg, and do lunges without pain. the lesion was still palpable but reduced in size and less tender. after three months of treatment, she could tolerate moderateto high-intensity exercise with no pain. the patient showed a complete recovery and was able to return to her usual sporting activities. at the time of writing, there were no signs of recurrence. discussion mo typically presents as an “inflammatory, rapidly growing and painful muscular mass”.[4] the patient being reported on presented typically with a tender, palpable, osseous mass with overlying erythema.[1] of the three types of mo identified previously (traumatic, non-traumatic, hereditary), the traumatic pattern best fits in this patient. athletes may sustain injury by either trauma (projectile or contact) or overuse, both of which have been linked to mo.[1] the patient fell off a horse three months prior to initial presentation resulting in blunt force trauma to the affected area. this case was selected to demonstrate that mo is a rare condition and can present similarly to malignant lesions, creating a diagnostic dilemma and emphasising the importance of excluding this differential. it also highlights the importance of conducting a thorough workup, from history and examination to a directed array of investigations in order to reach a definitive diagnosis. finally, the report revealed the challenges in dealing with an active child athlete whose lifestyle would be limited due to this condition and may regard historical sport-related impacts as insignificant. such a patient requires careful management to optimise their outcomes, minimise complications and allow a return to full activity. diagnosis of mo may be difficult and often requires radiological and, occasionally, histological confirmation.[4] several blood tests were initially performed on this patient, namely, full blood count, urea, electrolytes and creatinine, creactive protein, erythrocyte sedimentation rate, and creatine phosphokinase. the findings were unremarkable, apart from a moderate thrombocytosis. an mri revealed a heterogeneously enhancing mass with thin peripheral calcification within the right gluteus maximus, in keeping with the findings of myositis ossificans described in the literature. osteosarcoma is a possible differential and must be excluded before confirming the diagnosis of mo. radiology is insufficient in differentiating between the two, necessitating a biopsy.[2] the patient’s results yielded no histological evidence fig. 4. axial mri pelvis – complete resolution of soft tissue oedema (arrowheads) surrounding the mature lesion (arrow). central soft tissue t2 hyperintense and t1 isointense. axial measurement is 3.1 x 2cm. fig. 5. axial mri pelvis – fat signal present at periphery of the lesion (arrowhead) adjacent to the rim calcification (arrow) consistent with ossification. case report sajsm vol.34 no.1 2022 4 of malignancy and the findings were consistent with mo, confirming the diagnosis. physiotherapy and sporting activities were stopped to prevent further exacerbation of the lesion. initial treatment of mo aims to reduce pain and inflammation. indomethacin is recommended as prophylaxis and was prescribed in this case. it has been shown to reduce the extension of mo by inhibiting cox-1 and cox-2 enzymes, which play a role in regulating the differentiation of mesenchymal stem cells into osteoblasts.[5] surgical excision and radiation were not indicated in this case. surgery is only considered necessary if there is no improvement observed after 6 – 12 months of alternative management. radiation is generally avoided in children due to concerns about the potential carcinogenic effects it might have on the patient’s life in the future.[2] extracorporeal shock-wave therapy involves using single sonic pulses of short duration to induce a mechanical cavitation effect, not only fragmenting heterotopic calcification but also stimulating biological tissue repair.[6] it has been shown to have significant analgesic and antiinflammatory effects within a few weeks.[6] the procedure is minimally invasive and has few side effects, such as bruising, short-term swelling and tenderness.[6] this patient was successfully managed after two months of the conservative management, as evidenced by stabilisation followed by reduction in size of the lesion (see figure 3). her pain was dramatically reduced, enabling her to return to functioning normally. conclusion mo is rare and may resemble malignancy, necessitating a thorough workup. a high index of suspicion can avoid mismanagement and unnecessary treatment. this case of mo followed sport-related blunt force trauma and presented with the typical clinical, radiological, and histological findings of mo. the patient was managed successfully with conservative treatment, including nsaids and eswt. this case highlighted the importance of a thorough history, accurate diagnosis, and the significant impact eswt can have on the outcome of mo. ethical approval: the study was approved by the human research ethics committee of the university of the witwatersrand (m2111153). conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors would like to thank the child athlete and her parents for providing their informed consent to access the patient’s medical records, and permission to publish the case report. author contributions: jp conceived the study and obtained the case information. rs, rn, pg, ar, vm, nn, kt, and sr all contributed to the designing, drafting and revising of the manuscript. air, rts and jp supervised the study and refined the manuscript. all authors approved the final manuscript. references 1. walczak be, johnson cn, howe bm. myositis ossificans. j am acad orthop surg 2015;23(10):612-622. [doi:10.5435/jaaos-d14-00269] [pmid: 26320160] 2. galanis n, stavraka c, valavani e, kirkos j. unsupervised exercise-induced myositis ossificans in the brachialis muscle of a young healthy male: a case report. orthop j sports med 2017;5(7):2325967117718780. [doi:10.1177/2325967117718780] [pmid: 28795074] 3. yamaga k, kobayashi e, kubota d, setsu n, tanaka y, minami y, et al. pediatric myositis ossificans mimicking osteosarcoma. pediatr int 2015;57(5):996–999. [doi:10.1111/ped.12672] [pmid: 26508182] 4. lacout a, jarraya m, marcy py, thariat j, carlier ry. myositis ossificans imaging: keys to successful diagnosis. indian j radiol imaging 2012;22(1):35–39. [doi:10.4103/0971-3026.95402] [pmid: 22623814] 5. baird eo, kang qk. prophylaxis of heterotopic ossification – an updated review. j orthop surg res 2009;4(1):12. [doi:10.1186/1749-799x-4-12] [pmid: 19379483] 6. torrance da, degraauw c. treatment of post-traumatic myositis ossificans of the anterior thigh with extracorporeal shock wave therapy. j can chiropr assoc 2011;55(4):240-246. [pmid: 22131560] original research 68 sajsm vol 23 no. 3 2011 introduction women’s participation in sports has increased substantially over the past few years, and this growth, especially on a competitive level, has been accompanied by a number of health concerns including disordered eating (de) and menstrual disorders. 1,2 apart from the societal pressure on women to be beautiful and thin, many female athletes are also pressured by coaches or the type of sport they are competing in (i.e. lean-build sports) to maintain a low body weight for aesthetic and/or performance purposes. this often contributes towards the development of de and pathogenic bodyweight-control behaviours (i.e. restrictive eating, fasting, use of diet pills, laxatives and diuretics, binge-eating followed by purging) that can result in clinical eating disorders (i.e. anorexia nervosa and bulimia nervosa) and alterations in menstrual patterns. 1 potential long-term health consequences of de and menstrual disorders include chronic fatigue, anaemia, endocrine abnormalities, and osteoporosis, to name a few. 1,2 female student athletes may be at an even higher risk for de owing to the added pressure of maintaining an attractive and culturally acceptable body shape, and adapting to the new social and academic environment of a tertiary educational institution (e.g. college or university). reported prevalence of de and menstrual disorders in female university athletes varies and depends on a number of factors, including type of sport, level of participation, and type of questionnaire used to screen for de. 1-3 although a number of studies have reported a higher prevalence of de and menstrual disorders in female university athletes compared with non-athletes, particularly in elite female athletes competing in aesthetic, weightclass and endurance sports where leanness is emphasised, 4,5 other studies failed to demonstrate differences in the frequency of de and menstrual disorders between athletes and non-athletes, especially in sports where leanness is considered less important. 2,3 the primary aim of this study was therefore to determine the prevalence of de behaviour and menstrual disorders in a group of provincial-tonational level student netball players. methodology subjects and study design twenty-six white female netball players from a south african university volunteered to take part in this descriptive, cross-sectional study which was approved by the ethics committee of the north-west university. students representing the university’s 1st, 2nd or u/19a netball teams were invited to participate in the study. the majority of these players also represented a provincial and/or national netball team in the past three years. the characteristics of the subjects are summarised in table i. the subjects were informed of the nature of the study and written informed consent was obtained prior to the start of the study. pregnancy or known gynaecological problems were exclusion criteria. oral contraceptive use was not an exclusion criterion but the reason for use, i.e. to regulate menstrual cycle, was documented. abstract objective. the primary aim of this study was to determine the prevalence of disordered eating (de) behaviour and menstrual disorders in a group of provincial-to-national level student netball players. the secondary aim was to examine the relationship between body composition, energy intake, de and menstrual patterns in student netball players. methods. twenty-six white female netball players from a south african university volunteered to participate in this cross-sectional descriptive study. height, weight and body composition were measured. energy intake was assessed with 24-hour recalls and menstrual patterns were assessed with a menstrual history questionnaire. players also completed an eating disorder inventory (edi) and an eating attitudes test (eat-26) to assess de behaviour. results. collectively 14 players (54%) were identified with de behaviour and scored above the designated cut-off score for the eat-26 (≥20, n=3), the edi body dissatisfaction subscale (≥14, n=7), the edi drive for thinness subscale (≥15, n=3), and/or answered ‘yes’ (n=8) to de behavioural questions. eight players (31%) reported menstrual irregularities during the past 12 months, of whom four (15%) also reported secondary amenorrhoea (absence of ≥3 consecutive menstrual cycles) during training. five players (19%) presented with de behaviour, menstrual irregularity and primary and/or secondary amenorrhoea. reported energy intake was significantly lower in the players with menstrual irregularities and secondary amenorrhoea compared with the remaining players (p<0.05). conclusions. top female student netball players may have suboptimal energy intakes and suffer from de behaviour, menstrual irregularities and secondary amenorrhoea. players and coaches should be aware of these risks to avoid related health and performance consequences. lize havemann (phd exercise science) zelda de lange (msc nutrition) karen pieterse (bsc hons nutrition) hattie h wright (phd nutrition) centre of excellence for nutrition (cen), north-west university, potchefstroom, south africa correspondence to: l havemann-nel (lize.havemannnel@nwu.ac.za) disordered eating and menstrual patterns in female university netball players sajsm vol 23 no. 3 2011 69 for the purpose of the study, subjects were required to report to the laboratory for the assessment of height, weight and body composition. in addition, subjects were required to complete the following questionnaires: (i) a demographic and sport questionnaire for the attainment of socio-demographic information and training volume; (ii) three 24-hour dietary recalls for the estimation of mean reported energy intake; (iii) a menstrual history questionnaire to assess menstrual patterns; and (iv) an eating disorder inventory (edi) and an eating attitude test (eat-26) to assess risk for disordered eating. 6,7 weight, height and body composition weight and height were recorded to the nearest decimal position with an electronic precision health scale (model uc-300, a&d company ltd., tokyo, japan) and an invicta stadiometer (model ip 1465, invicta, london, uk), respectively. body composition (fatfree mass, fat mass and body fat percentage) was determined with air-displacement plethysmography (adp) using the bodpod body compositions system (model 2000a, cosmed usa, inc., concord, ca, usa) as described by mccrory et al. 8 dietary and energy intake dietary and energy intake were recorded with a 24-hour dietary recall on three non-consecutive days. all dietary data were analysed with the foodfinder tm 3 software program (version 1.1.3, 2002, medical research council, sa) and expressed in kilocalories. the possibility of under-reporting of energy intake in the present study was evaluated by the calculation of the mean reported energy intake (ei) in relation to calculated basal metabolic rate (bmr) (ei:bmr) according to the method of goldberg. 9 the ei:bmr was adjusted for females with different physical activity levels (pal) as described by black 10 and values <1.11 (cut-off for females with a medium pal) were considered as possible under-reporting. 10 disordered eating de behaviour was assessed with the eat-26 questionnaire 6 and the edi. 7 the validity and reliability of both questionnaires have been described previously. 6,7 the eat-26 the eat-26 is a standardised questionnaire designed to identify eating disorder risk and de behaviour in high school, university and other special risk samples such as athletes. the instrument consists of 26 items rated on a 6-point likert-type scale together with four eating behaviour questions which require a ‘yes’ or ‘no’ response. 6 respondents with a total eat-26 score of 20 or higher and/or who answered ‘yes’ to any of the behavioural questions were classified with de behaviour. 6 edi the edi is a self-reported measure designed to assess attitudes, feelings and behaviours typically associated with eating disorders (eds), and has been found to be a suitable screening instrument for eds in a non-clinical setting. 7 the edi consists of 64 items rated on a 6-point likert-type scale, and is subdivided into eight subscales. 7 total edi score and independent subscale scores were used to make comparisons between players with menstrual irregularities and those without. the edi drive for thinness (edi-dt) and body dissatisfaction (edi-bd) subscales have been shown to predict the development of eds and have been used as selection criteria when investigating the prevalence of eds in elite athletes, 11 and will therefore also be used to identify players with ed risk and de behaviour in the present study. respondents scoring ≥15 in the edi-dt and/or ≥14 in the edi-bd subscale were considered to be ‘at risk’ for eds. 11 menstrual patterns menstrual patterns were assessed with a menstrual history questionnaire that included questions regarding age of menarche, frequency and regularity of menstrual cycles, training-associated changes in cycle frequency and regularity, and oral contraceptive use. for the purpose of this study menstrual dysfunction included a history of secondary amenorrhoea (defined as the absence of three or more consecutive menstrual periods at any time since menarche) and/or primary amenorrhoea (defined as the absence of menstruation by age 15). 12 menstrual irregularity was defined as one or more of the following: (i) cycles not occurring every 28 34 days; (ii) fewer than 10 cycles in the past 12 months; and/or (iii) fewer than 5 cycles in the past 6 months. statistical analysis data were analysed using statistica analysis software (version 10, statsoft, tulsa, ok, usa). normally distributed descriptive data were reported as means ± standard deviations (sd) and non-parametric data were reported as medians and inter-quartiles ranges. spearman rank correlations were used to explore associations between energy intake, training volume, body composition and de (eat-26, total edi and edi subscale scores), and non-parametric mann-whitney u-tests were performed to test differences between groups with different menstrual patterns and de behaviour. results energy intake and training volume total mean reported energy intake and training volume are summarised in table i. mean reported energy intake in relation to calculated basal metabolic rate (ei:bmr) was 1.33±0.37. six players (23%) had an ei:bmr value of <1.11 (1.05, 0.90, 0.63, 0.91, 0.95, and 0.90, respectively) which would normally be considered under-reporting. 10 however, since low energy intakes among female athletes are not uncommon, 2 possible under-reporting was noted but not excluded from the analysis. furthermore, the under-reporting data did not significantly lower mean reported energy intake (8.7±2.4 v. 9.5±2.1 mj, p=0.19) and three of the under-reporters were identified with de behaviour. disordered eating total eat-26 scores of the group of female netball players (n=26) are summarised in fig. 1. total mean eat-26 score was 9.4±6.9, and table i. subject characteristics (n=26) characteristic mean (±sd) range age (years) 19±1 18 22 weight (kg) 70.8±10.8 55.0 91.8 height (m) 1.75±0.06 1.56 1.84 body mass index (kg/m 2 ) 23.2±2.8 19.4 28.7 body fat percentage 25.2±4.8 14.6 36.5 energy intake (mj) 8.7±2.4 4.4 14.6 training volume (sessions/week) 5±1 3 6 training volume (sessions/day) 1.7±0.6 1 3 sd = standard deviation. 70 sajsm vol 23 no. 3 2011 10 players (38%) responded ‘yes’ to one or more of the behavioural questions and/or scored above the designated cut-off score (≥20) in the eat-26. four of the 10 subjects also scored ≥15 in the edidt and/or ≥14 in the edi-bd. total mean edi-bd and edi-dt subscale scores were 9.5±5.8 and 5.5±5.3, respectively. seven subjects (27%) scored ≥14 in the edi-bd and three subjects (12%) scored ≥15 in the edi-dt. collectively 14 players (54%) scored above the designated cut-off scores for either/or the eat-26, edi-bd, edi-dt, and/or answered ‘yes’ to one or more of the eat-26 behavioural questions, identifying them with de behaviour and an increased ed risk. no significant differences were demonstrated for weight, training volume or energy intake when the group with de behaviour (n=14) was compared with the group without de behaviour (n=12). there was no association between reported energy intake, training volume, body composition, total eat-26 score or total edi score in this group of female netball players. a weak, but positive correlation was reported between energy intake and edi-bd subscale score (r=0.39, p<0.05). training volume (sessions/week) was negatively correlated with edi-dt and perfectionism subscale scores (r=-0.42 and r=-0.46 respectively, p<0.05). menstrual patterns reported menstrual patterns, including menstrual regularity, history of menstrual dysfunction, changes in menstrual cycle in response to the athletic season and oral contraceptive use are summarised in table ii. eight of the subjects (31%) reported irregular menstrual cycles during the past 12 months, of whom 6 players (23%) also reported a history of menstrual dysfunction, e.g. the absence of menstruation by age 15 (primary amenorrhoea) and/or the absence of three or more consecutive menstrual periods at any time since menarche (secondary amenorrhoea). three of these players also reported the use of oral contraceptives with documented reason for use: ‘to regulate irregular menstrual cycle’. five of the players with irregular menstrual cycles and menstrual dysfunction were also identified with de behaviour. when comparing the group with irregular menstrual cycles (n=8) with the group with regular menstrual cycles (n=18) (table iii), reported energy intake was significantly lower in the irregular compared with the regular group (p<0.001). in addition, total eat-26, total edi, and edi-dt subscale scores, although not significantly, were higher in the group who reported irregular menstrual cycles. the athletic season had the biggest impact on the menstrual patterns in this specific group of netball players, with the majority of subjects (n=15, 58%) reporting changes in menstrual cycle during the athletic season. of note are the four subjects (15%) who reported the absence of three or more consecutive menstrual periods during the athletic season (secondary-training amenorrhoea). although the sample size of the group with secondary-training amenorrhoea was very small (n=4), non-parametric mann-whitney u-tests were fig. 1. total eat-26 scores. table ii. menstrual patterns and oral contraceptive use (n=26) regularity of menstrual cycles n (%) regular (every 28 34 days/10 -12 cycles during past 12 months) 18 (69%) irregular (not every 28 34 days/<10 cycles during past 12 months/<5 cycles during past 6 months) 18 (31%) history of menstrual dysfunction primary amenorrhoea 1 (3.8%) secondary amenorrhoea 5 (19%) changes in cycle during athletic season yes 15 (58%) no 11 (42%) type of changes in response to training shorter cycle 6 (23%) increased length of cycle 5 (19%) absence of 3≤ consecutive cycles (secondary-training amenorrhoea) 4 (15%) oral contraceptive use total oral contraceptive use 4 (15%) oral contraceptive use to ‘regulate menstrual cycle’ 3 (12%) oral contraceptive use to ‘treat skin problems’ 1 (3.8%) table iii. differences between the groups with regular and irregular menstrual cycles characteristic irregular (n=8) regular (n=18) p-level weight (kg) 65.1 (62.6-74.7) 69.1 (63.0-78.5) p=0.567 height (m) 1.74 (1.70-1.79) 1.75 (1.70-1.81) p=0.461 bmi (kg/m 2 ) 22.1 (21.0-23.7) 22.9 (21.3-26.2) p=0.605 body fat percentage 24.6 (20.9-26.7) 25.3 (22.8-28.3) p=0.531 energy intake (mj) 6.4 (5.9-7.4) 9.2 (8.2-11.4) p<0.001 training volume (sessions/week) 5.0 (3.5-5.0) 5.0 (4.0-6.0) p=0.515 total eat-26 score 12.0 (6.0-19.5) 8.0 (3.0-10.0) p=0.311 total edi score 37.0 (23.5 -56.5) 26.0 (22.0-36.0) p=0.285 edi-bd subscale score 8.5 (5.0-11.5) 10.0 (4.0-14.0) p=0.495 edi-dt subscale score 10.0 (2.5-13.5) 3.0 (2.0-5.0) p=0.144 values are medians (inter-quartile ranges). sajsm vol 23 no. 3 2011 71 performed to examine possible differences between players with secondary-training amenorrhoea and those without. on analysis, the players with secondary-training amenorrhoea reported a significantly lower energy intake compared with the players without secondary-training amenorrhoea (6.4 (6.0 7.0) v. 8.6 (7.7 11.0) mj, p<0.05). although three of the four players were identified as possible under-reporters (ei:bmr <1.11), these players were also identified with de behaviour (scored above the designated cut-off in the eat-26, edi-bd and/or edi-dt). the players with secondarytraining amenorrhoea also scored significantly higher in the edi-dt and perfectionism subscales (10.5 (7.0 13.5) v. 3.0 (1.0 6.0), and 10.5 (7.5 14.5) v. 4.0 (2.0 8.0), respectively, p<0.05) as well as in the eat-26 bulimia and food preoccupation subscale (3.0 (2.3 3.5) v. 2.0 (1.0 2.0), p<0.05). discussion the present study investigated de behaviour and menstrual patterns in a group of provincial-to-national level student netball players enrolled at a south african university. collectively 14 players (54%) were identified with de behaviour, eight players (31%) reported menstrual irregularities during the past 12 months, of whom four (15%) reported secondary amenorrhoea during training, and five (19%) presented with de behaviour and menstrual irregularity and dysfunction. to our knowledge data on de behaviour and menstrual patterns in female university netball players are scarce. the prevalence of de in female university athletes reported in the literature is inconsistent and can be attributed to differences in sampling and the use of different assessment instruments.1-3 the outcome on de behaviour based on the eat-26 (score ≥20) in the group of university netball players in the present study (12%) is comparable with those of hoerr et al., 13 kirk et al. 14 and beals and manore 15 who also applied the eat-26 and reported a prevalence of 12%, 9.6% and 15%, respectively in female university athletes/athletes aged 18 24 years. kirk et al. 14 assessed a group of 94 ncaa division 1 collegiate female athletes competing in a number of non-lean-build sports including soccer (n=24, 17% scored ≥20), tennis (n=10, 0% scored ≥20), softball (n=18, 5.6% scored ≥20), basketball (n=11, 0% scored ≥20) and lacrosse (n=31, 13% scored ≥20). beals and manore 15 used the edi-bd subscale in conjunction with the eat-26 to assess de behaviour in a group of 96 collegiate female athletes competing in team/anaerobic sports including golf, softball, tennis, volleyball and field events. however, they applied a lower edi-bd cut-off point than in the present study (12 v. 14), explaining the higher percentage of female athletes identified with ‘elevated’ edi-bd scores (42% v. 27%) compared with the present study. similar to the present study, torstveit et al. 16 showed that 22% of 96 elite female athletes (mean age 23.5 years) competing in non-lean-build sports (including technical, ball game and power sports) scored ≥14 on the edi-bd. in addition, torstveit et al. 16 reported that 6.3% of athletes scored ≥15 on the edi edi-dt subscale. reinking and alexander 17 also reported a lower edi-dt outcome (2.9%) compared with the present study in a group of 68 females competing in non-lean-build sports. a smaller sample size, a higher mean bmi (23.7±2.8 v. 22.7±2.2 kg/m 2 ) and a higher body weight (70.8±10.8 v. 66.8±8.3 and 65.6±7.8 kg) in the present study can possibly explain differences in edi-dt outcomes. reported menstrual irregularity and menstrual dysfunction in the present study concur with the literature on menstrual patterns in collegiate females competing in non-lean-build sports. beals and manore 15 showed that 24% of 96 collegiate females competing in team/anaerobic sports reported menstrual irregularities and 4.3% reported primary amenorrhoea. torstveit and sundgot-borgen 18 reported that 21% of 302 elite female athletes competing in ball sports reported a history of menstrual dysfunction (delayed menarche and secondary amenorrhoea) and 13% reported current secondary amenorrhoea. in another study from the same authors, 19 9.3% of female football players and 19% of female handball players reported current secondary amenorrhoea. although beals and hill 20 reported a much higher prevalence of menstrual irregularities (72%) in a group of 47 female athletes competing in intercollegiate nonlean-build sports (tennis, field hockey and softball), they applied less strict criteria for identifying menstrual irregularity (<12 cycles in the past 12 months, <6 cycles in the past 6 months, >10-d variation). the frequency of menstrual dysfunction (delayed menarche and secondary amenorrhoea), however, was comparable to the present study (17% v. 19%). 20 the disruption of normal menses with exercise training has long been recognised and is more common among athletes than non-athletes. 5,11 a number of factors have been implicated in the development of menstrual disturbances and include de, low energy intake, and strenuous exercise training. 1 indeed, reported energy intake in the present study was significantly lower in the players who reported menstrual irregularities and secondarytraining amenorrhoea compared with those players without menstrual disorders. furthermore, although not significant, players with menstrual irregularities reported higher eat-26 and edi scores compared with the regular group. in addition, subjects with secondary-training amenorrhoea scored significantly higher on the edi-dt and perfectionism subscales (p<0.05) as well as the eat-26 bulimia and food preoccupation subscales (p<0.05) compared with the players without secondary-training amenorrhoea. it is difficult to explain the weak positive correlation between energy intake and edi-bd as well as the inverse relationship between training volume and edi-dt and perfectionism subscale scores, as de in athletes is generally associated with a lower energy intake and higher training volume. these correlations could possibly be the result of multiple testing. other limitations in the present study that warrant mentioning include a small sample size and the fact that a control group of non-athletes was not included in the study. in conclusion, reported menstrual irregularity, menstrual dysfunction and de behaviour in the present study seem to be in line with the literature on prevalence of menstrual disorders and de in female student athletes participating in non-lean-build sports. the present study therefore highlights the fact that student netball players are also at risk for developing eds, restricting energy intakes, and experiencing menstrual disorders. this is of practical significance to university netball players, parents, netball coaches and health professionals working with netball players to increase awareness, facilitate intervention and prevent the health and performance consequences associated with de behaviour and menstrual disorders. references 1. nattiv a, loucks ab, manore mm, et al. american college of sports medicine position stand. the female athlete triad. med sci sports exerc 2007;39(10):1867-1882. 2. beals ka, meyer nl. female athlete triad update. clin sports med 2007;26(1):69-89. 3. coelho gm, soares ede a, ribeiro bg. are female athletes at increased risk for disordered eating and its complications? appetite 2010;55(3):379387. 4. sundgot-borgen j. disordered eating and exercise. scand j med sci sports 2004;14(4):205-207. 5. sundgot-borgen j, torstveit mk. prevalence of eating disorders in elite athletes is higher than in the general population. clin j sport med 2004;14(1):25-32. 72 sajsm vol 23 no. 3 2011 6. garner dm, olmsted mp, bohr y, garfinkel pe. the eating attitudes test: psychometric features and clinical correlates. psychol med 1982;12(4):871878. 7. garner dm, olmstead mp, polivy j. development and validation of a multidimensional eating disorder inventory for anorexia nervosa and bulimia. int j eat dis 1983;2(2):15-34. 8. mccrory ma, gomez td, bernauer em, mole pa. evaluation of a new air displacement plethysmograph for measuring human body composition. med sci sports exerc 1995;27(12):1686-1691. 9. goldberg gr, black ae, jebb sa, et al. critical evaluation of energy intake data using fundamental principles of energy physiology: 1. derivation of cut-off limits to identify under-recording. eur j clin nutr 1991;45(12):569581. 10. black ae. the sensitivity and specificity of the goldberg cut-off for ei:bmr for identifying diet reports of poor validity. eur j clin nutr 2000;54(5):395404. 11. sundgot-borgen j. prevalence of eating disorders in elite female athletes. int j sport nutr 1993;3(1):29-40. 12. practice committee of american society for reproductive medicine. current evaluation of amenorrhoea. fertil steril 2008;90(5 suppl):s219-25. 13. hoerr sl, bokram r, lugo b, bivins t, keast dr. risk for disordered eating relates to both gender and ethnicity for college students. j am coll nutr 2002;21(4):307-314. (http://www.jacn.org/content/21/4/307.full) 14. kirk g, singh k, getz h. risk of eating disorders among female college athletes and nonathletes. journal of college counselling 2001;4(fall):122132. 15. beals ka, manore mm. disorders of the female athlete triad among collegiate athletes. int j sport nutr exerc metab 2002;12(3):281-293. 16. torstveit mk, rosenvinge jh, sundgot-borgen j. prevalence of eating disorders and the predictive power of risk models in female elite athletes: a controlled study. scand j med sci sports 2008;18(1):108-118. 17. reinking mf, alexander le. prevalence of disordered-eating behaviours in undergraduate female collegiate athletes and nonathletes. j athl train 2005;40(1):47-51. (http://www.ncbi.nlm.nih.gov/pmc/articles/ pmc1088345/) 18. torstveit mk, sundgot-borgen j. participation in leanness sports but not training volume is associated with menstrual dysfunction: a national survey of 1276 elite athletes and controls. br j sports med 2005;39(3):141-147. (http://bjsm.bmj.com/content/39/3/141.full) 19. sundgot-borgen j, torstveit mk. the female football player, disordered eating, menstrual function and bone health. br j sports med 2007;41(suppl 1):i68-72. (http://bjsportmed.com/content/41/suppl_1/i68.full.html) 20. beals ka, hill ak. the prevalence of disordered eating, menstrual dysfunction, and low bone mineral density among us collegiate athletes. int j sport nutr exerc metab 2006;16(1):1-23. introduction elbow injury in sports is dependent on the nature of the game. welldefined injury patterns like the valgus hyperextension syndrome have been reported in throwers, in racquet sports and in baseball. the demands of throwing in cricket theoretically do not involve significant stress on the elbow. we report for the first time a typical case of valgus hyperextension syndrome in an international cricket fast bowler. the mechanism of trauma seems to involve a terminal thrust at the elbow with stress concentration on the posterior and lateral sides and with some degree of distraction on the medial side. case report a 29-year-old international sri lankan test cricket fast bowler was seen in 2004, with a 6-month history of left elbow pain and limited elbow extension (bowling arm). he had insidious pain and motion restriction without significant injury or swelling. motion range was 15 o 140 o , with tenderness below and anterior to the medial epicondyle and olecranon tip. radiographs of the elbow showed osteophytes at the postero-medial aspect and tip of the olecranon, and anteriorly at the coronoid tip (fig. 1a, b). mr imaging confirmed osteophyte location and showed attenuation of the medial collateral ligament, with medullary oedema at the lateral side of the elbow (fig. 2). the patient refused arthroscopy, and opted for total abstinence from throwing and fast-bowling for 12 weeks. he started a training programme designed to strengthen his forearm flexor-pronator and triceps group of muscles. he resumed international cricket within 6 months without limitations in his bowling and throwing. he has since played in the 2007 cricket world cup, numerous test and one-day matches, and has taken more than 100 international wickets since recovering from injury. discussion overuse injuries constitute the vast majority of elbow disorders in athletes who throw as a requirement of the sport. 3 throwing motion is divided into six phases, 1 namely wind-up, early cocking, late cocking, acceleration, deceleration and follow-through. all phases, except wind-up, are associated with elbow injury. the overhead throwing motion is needed in many sports like baseball pitching, tennis serve, volleyball spike and rugby pass. baseball pitching generates large valgus/extension forces. 2,5 biomechanical testing has resulted in estimated valgus forces as high as 64 nm at the elbow during the late cocking and early acceleration phases of throwing with compressive forces of 500 n at the lateral radiocapitellar articulation as the elbow moves from approximately 110 o to 20 o of flexion, with throwing velocities as high as 3 000 o .s -1 . 2,5 large valgus loads with rapid elbow extension produce tensile stresses on medial compartment restraints (ulnar collateral ligament, flexor-pronator mass and ulnar nerve) and shear stress in the posterior compartment (posteromedial tip of the olecranon, trochlea, olecranon fossa) and compression stresses laterally (radial head, capitellum). 6 this phenomenon has been termed ‘valgus extension overload syndrome’ and forms the basic pathophysiological model behind elbow injuries in the throwing athlete. 6 overuse injuries in cricketers occur predominantly in bowlers or fielders. 4 there are no published data on bowlers’ elbow overuse injury, although anecdotal reports exist. there are 3 distinct phases of the bowling action: the run-up, the delivery stride and the followthrough. 4 in the delivery stride, the bowler winds the arm into a hyperflexed position and then brings the arm over the shoulder in full circumduction, releasing the ball at the start of the downward arc. during the delivery phase of the bowling action, the arm must be kept as straight as possible according to the laws of the game, otherwise it amounts to throwing or chucking. the bowler is required to not straighten the elbow more than 15° during the delivery phase of the bowling action. this is different to baseball pitching or throwing a ball from the outfield. thus valgus extension overload seems improbable in cricket bowling, as there is minimal elbow jerking during the terminal delivery arc. however, for valgus extension overload in this particular bowler, we presume that some terminal jerk or arm straightening at delivery stage produced valgus/extension forces. the repetitive nature of case report valgus extension overload syndrome of the elbow in a test cricket fast bowler correspondence: professor m s dhillon 92, sector 24 a, chandigarh india tel.: (91) 9815951090 fax: (91) 172 2744401 e-mail: drdhillon@gmail.com mandeep s dhillon (ms, mnams)1 prabhudev prasad (ms)1 akshay goel (ms)2 himmat s dhillon (bpt)3 1 department of orthopaedics, post graduate institute of medical education and research, chandigarh, india 2 government medical college and hospital sector 32, chandigarh, india 3 department of physiotherapy, guru nanak dev university, amritsar, india sajsm vol 20 no. 4 2008 119 terminal olecranon impingement at delivery could cause pressure symptoms, since the elbow is stressed into some valgus at terminal extension in fast bowlers. the other reason could be the fault in elbow position while throwing the ball during fielding. although we were not able to ascertain the exact cause of valgus extension overload in this bowler, conservative treatment was successful and he could return to his original level of sport participation after 6 months. since this test bowler presented to us, the senior author has noted similar features of pain associated with throwing in other cricketers. some test batsmen have been recorded to have similar mri changes when clinically painful elbows were evaluated (john orchard: personal communication). the logical cause of injury in these players is throwing during fielding, but causes related to their batting action need to be examined more carefully. this case is reported to highlight its uniqueness and to emphasise the possibility of overload syndromes in the differential diagnosis of elbow problems in cricketers. more studies are needed to identify players with elbow pain at all levels of the sport, and in particular the relationship to age, duration of cricket career, mode of onset, player type and duration of symptoms with the goal of identifying the specific cause. references 1. digiovane m, jobe f, pink m, et al. an electromyographic analysis of the upper extremity in pitching. j shoulder elbow surg 1992; 1: 15-25. 2. fleisig gs, andrews jr, dillman cj, escamilla rf. kinetics of baseball pitching with implication about injury mechanism. am j sports med 1995; 23: 233-9. 3. gerbino pg. elbow disorders in throwing athletes. orthop clin n am 2003; 34: 417-26. 4. myers p, o’brien bs. cricket injuries, rehabilitation and training. sports med arthroscopy rev 2001; 9: 124-36. 5. werner sl, murray ta, hawkins rj, gill tj. relationship between throwing mechanics and elbow valgus in professional baseball pitchers. j shoulder elbow surg 2002; 11: 151-5. 6. wilson fd, andrews jr, blackburn ta, mccluskey g. valgus extension overload in the pitching elbow. am j sports med 1983; 11: 83-8. 120 sajsm vol 20 no. 4 2008 fig. 2. mri showing fluid inside the joint, osteophyte formation and signal change in the olecranon. fig. 2. mri scan showing fluid inside the joint, osteophyte formation and signal change in the olecranon. (a) (b) fig. 1a and 1b. osteophyte formation at the tip of the olecranon and lip of coronoid. fig. 1a and 1b. osteophyte formation at the tip of the olecranon and tip of the coronoid. a b introduction research on heat storage differences between the upper body and lower body for paraplegic athletes is sparse. however, a few studies have reported heat storage when evaluating the effectiveness of various cooling interventions. webborn et al. 1 examined the effects of two cooling strategies (pre-cooling and cooling during exercise) on thermoregulatory responses of tetraplegic athletes. the authors, using a repeated measures design, examined two strategies during 28 minutes of intermittent arm crank exercise. the authors reported no difference (p=0.39) in heat storage between a control trial (3.62±0.4 j.g -1 ) and either intervention during pre-cooling (4.17±0.4 j.g -1 ) and cooling during exercise (3.15±0.35 j.g -1 ). price and campbell 2 examined upperv. lower-body skin temperature in paraplegic athletes. results from arm ergometry exercise indicated that paraplegic athletes (v. able-bodied athletes), showed lower skin temperatures for the lower body after 90 minutes of work at 80% of peak heart rate (hr) in room temperature . however, upper-body skin temperature was also lower for the paraplegic group v. the able-bodied group. the authors speculated that this could be due to atrophied musculature and/or an atrophied vascular system below the level of lesion. 2 unfortunately no information was provided on rectal or oesophageal temperatures (two accepted measures of core body temperature), so heat storage cannot be calculated for the upper-body and lower-body regions. furthermore, no effort was made to match groups for fitness. in general, paraplegics seem to adequately regulate body core temperature at rest; however, they show a greater increase in core temperature when compared with able-bodied (ab) subjects during exercise and/or working conditions work. 3 furthermore, it has been demonstrated that individuals with a t6 (thoracic) lesion and below are subjected to smaller increases in core temperature than those individuals with a lesion above t6. these individuals, in turn, demonstrate smaller increases than those with tetraplegia (cervical lesions). 4 individuals with a spinal cord injury at or above t6 are prone to episodes of autonomic hyperreflexia when exposed to incompensable stimuli. these responses have been well documented by jacobs and nash, 5 who further suggest that a common stimulus amongst others is a sudden rise in core temperature. there seems to be a lack of knowledge regarding heat storage differences between upper-body (hs upper) and lower-body (hs lower) regions over the period of an exercise bout, particularly in spinal cord injured athletes (sci) athletes. understanding the heat storage of sci athletes will illuminate both the thermal physiology as well as the circulatory function of this group. furthermore, enhancing the knowledge of thermal physiology within this cohort could aid in the development of more effective cooling interventions. for example, original research heat storage in upper and lower body during high-intensity exercise in athletes with spinal cord injuries abstract background: the thermophysiology of athletes with spinal cord injuries (sci) is not well understood. spinal cord lesions impact muscle mass, thermoregulatory neural signals and circulatory function. understanding sci thermoregulation physiology would benefit exercise function. therefore, this study was designed to describe heat storage in the upper and lower bodies of sci and able-bodied (ab) athletes. procedure: seven sci and 8 ab athletes (matched for armcrank vo2 peak) performed a ramp protocol in an environment similar to an indoor competitive environment (21˚c±1.5˚c, 55±3% relative humidity). results: sci athletes experienced similar upper-body heat storage of 0.82±0.59 j.g -1 and lower-body heat storage of 0.47±0.33 j.g -1 compared with that of ab athletes at 0.80±0.61 j.g -1 and 0.27±0.22 j.g -1 for upper and lower body, respectively. there were no significant differences between groups for rectal temperature (trec) or oesophageal temperature (tes). however, mean skin temperature (msk) was significantly higher for sci throughout the exercise bout (p=0.006). conclusions: the results of this study suggest that sci and ab athletes appear to thermoregulate in a similar manner, though sci tend to store slightly more heat. correspondence: r c pritchett department health human performance and nutrition central washington university 400 east university way ellensburg, wa, 98926 tel: 509-963-1338 fax: 509-963-1848 e-mail: pritcher@cwu.edu robert c pritchett (phd)1 james m green (phd, facsm)3 kelly l pritchett (phd, rd, cssd)1 phillip bishop (phd)2 1 department of health, human performance and nutrition, central washington university, ellensburg 2 department of kinesiology, university of alabama, tuscaloosa 3 department of health, physical education and recreation, university of north alabama, florence sajsm vol 23 no. 1 2011 9 the lower skin temperatures in sci participants reported by price et al. 6 may reflect a higher core temperature and reduced cutaneous vasodilatation, suggesting less effectiveness of skin cooling. a reduction in skin cooling has recently been noted by pritchett et al., 7 where the authors highlighted a decrease in sweat response among participants with sci, which led to a decreased ability to thermoregulate. this study therefore proposes to describe the heat storage dynamics over the course of a ~35-minute graded exercise bout under simulated gymnasium playing conditions (20˚c±1˚c; 45 65±0.1% relative humidity) in both sci and ab participants. method participants fifteen volunteers gave their informed consent to participate in this investigation, which had received approval by the university of alabama institutional review committee. the group was comprised of 7 paraplegic athletes (sci) and 8 ab upper-body trained athletes (see table i). ab athletes were wheelchair basketball team members absent of sci (n=4), and the remainder (n=4) were from the university swimming team. based on an alpha level of 0.05 an effect size of 1.0, a sd of 0.5 jxg -1 for heat storage, and a power of 0.80, an a priori power analysis indicated 7 subjects would be needed. 8 exercise tests participants visited the laboratory on two separate occasions. on the first occasion, volunteers performed an incremental arm-crank exercise (ace) test to determine vo2 peak with gas exchange indices collected using a vacumed vista mini cpx metabolic measurement system (vacumed, vista, ca). this involved two 5-minute submaximal exercise stages of arm-crank exercise (30 w and 50 w) separated by 1 minute of passive recovery. 9 once the two submaximal ace stages and a rest stage had been completed, volunteers exercised to volitional exhaustion at a ramp rate of 20 w every 2 minutes from an initial level of 110 w. all tests were conducted on a cycle ergometer (monark 850e, varberg, sweden) adapted for upper-body exercise. participants were instructed to maintain at least 50 rev. min -1 throughout the test. for the second laboratory visit the exercise test consisted of multiple stages, beginning at a workload of 35 w. resistance of each stage was held constant for 7 minutes. at the end of each stage, participants had a 1-minute passive recovery. the workload of each stage increased by 35 w, until such time that heat production exceeded heat dissipation as evidenced by a sudden increase in the time-slope of the tes. the increase in tes was identified as critical when it was greater than 0.2˚c -1 per minute. 10 temperature measures were conducted during the second laboratory visit only. temperature measures on arrival at the laboratory for the incremental test, thermocouples (physitemp instruments inc., clifton, nj, usa) were positioned for measurement of rectal (trec) and oesophageal temperatures (tes). the oesophageal thermocouple was inserted with the following procedure. the inside of the nose of the subject was swabbed with a mild anaesthetic jelly (7.5% benzocaine), and a light covering of jelly was also placed on the distal end of the thermistor. a single spray of a topical anaesthetic (cetacaine, 14% benzocaine, cetylite ind., pennsauken, nj usa) was sprayed on the back of the throat. after 2 minutes, the volunteers advanced the oesophageal probe through the nose and to the pharynx. at this point the probe was withdrawn slightly, and the volunteer was then requested to drink water through a right-angle straw and at the same time the probe was advanced into the oesophagus to a length of one-fourth of the volunteer’s supine height and then taped to the nose and across the shoulder. 11 a flexible rectal thermocouple (trec) probe was self-inserted ~8 cm beyond the anal sphincter. the rectal probe was securely taped, and 10 sajsm vol 23 no. 1 2011 table i. anthropometric and physiological measurements (means±sd) for able-bodied (ab) and spinal cord injured (sci) participants (level of lesion and completeness of injury presented for sci) sci (n=7) ab (n=8) subject age height (cm) weight (kg) injury level vo2 peak l.min -1 body fat (%) subject age height (cm) weight (kg) vo2 peak l.min -1 body fat (%) 1 23 170 60.0 t12/l1 2.06 25 1 21 185 73.0 3.20 14 2 31 174 44.5 t5 complete 2.02 36 2 29 179 77.0 2.90 12 3 23 189 65.8 t11 complete 2.89 10 3 23 198 93.0 4.10 16 4 19 174 57.0 t12 complete 1.95 12 4 28 165 70.0 2.38 23 5 26 172 54.4 t6 incomplete 2.93 13 5 23 152 69.0 1.98 32 6 20 157 44.4 t3 complete 1.81 18 6 38 155 64.0 2.04 20 7 26 176 51.0 t11 complete 2.60 27 7 24 160 66.0 2.50 25 8 38 153 48.0 1.90 13 mean ± 24 173 53.9* 2.3 20 28 168 70.0 2.60 19 sd 4 9 7.9 0.5 10 7 17 12.7 0.80 7 * sci significantly different to ab (p<0.05). the thermocouple wire was passed over the back of the wheelchair to minimise interference with arm cranking. skin temperature (tsk) was continuously monitored from thermocouples placed at the following sites: forehead, forearm, upper arm, back, chest, thigh and calf. thermocouples were attached to the skin using adhesive tape, cut around the head of the thermocouple, which held thermocouples in place without adding insulation. heat storage was calculated from the formula by havenith et al. 12 heat storage for the upper-body region was calculated using ∆tes and ∆tsk by tabulating the weighted mean skin temperature between forearm (20%), back (40%) and chest (40%). lower-body heat storage was calculated using ∆trec and ∆tsk, which was calculated using the mean skin temperature (thigh 70% and calf 30%) from the formula of ramanathan. 13 heat storage for each region was calculated where: heat storage = (0.8∆ trec or tes + 0.2∆ tskin) x cb, where cb is the specific heat capacity of body tissue (3.49j x g -1 x ˚c -1 ). statistical analysis heat storage for the upper body (hsupper) and heat storage for the lower body (hslower) were compared using paired t-tests. level of significance was set at alpha≤0.05. a one-way analysis of variance was used to compare the difference between sci athletes and matched ab athletes. furthermore, to allow for a depletion of subjects due to differentiated termination time, a harmonic mean was calculated and analysis over time using a repeated measures anova with a bonferroni post hoc test employed where necessary. results descriptive statistics (means and standard deviations) for sci and ab are presented in table i. there was no difference in absolute vo2 peak, stature and age. however, body mass was significantly different between groups (p=0.03). ab athletes were matched to sci athletes based on activity status, vo2 peak, with 3 of the 8 ab being active participants in college wheelchair basketball. thermoregulatory responses during exercise for sci and ab were compared and presented graphically. there was no significant difference (p=0.06) in tes between sci (38.0±0.2˚c) and ab (37.6±0.4˚c) (fig. 1). however, it was noted that there was a greater increase in tes for sci within the last two stages of the exercise bout. trec (fig. 2) for both groups were similar with no statistical difference between groups (p>0.05). figures are reported with the sample size, as the increasing intensity lead to a depleted sample size as individual termination points were reached. one subject (t3 lesion level) completed two stages, and was matched with an ab subject that completed two stages. only two subjects could not complete the final stage (90 w). data are presented for all stages that more than 70% of the subjects completed. analysis of variance indicated that mean skin temperature for the lower body (msk) (fig. 4) for sci subjects was significantly higher than for ab throughout the exercise bout (p=0.006). however, mean skin temperature for the upper body (fig. 3) was significantly different than for the first (30 w) stage (sci: 35.2±0.9˚c, ab: 33.4±0.8˚c) and second stage (50 w) (sci: 33.4±0.9˚c, ab: 33.7±1.0˚c). however, for the last two stages, there were no significant differences detected between groups. there was no significant difference observed between upper body and lower body for heat storage between sci and ab athletes (p=0.38, fig. 5). furthermore, it is interesting to note that there was a significant difference observed between hsupper and hslower body for sci (0.82±0.59 j.g -1 and 0.47±0.33 j.g -1 ) (p=0.04) and also for ab (0.80±0.61 j.g -1 and 0.27±0.22 j.g -1 ) (p=0.03). heat storage for sci and ab per stage for both upper and lower body are presented in figs 6 a and b, respectively. there was no significant difference for hs between stages for either group. discussion the current study was undertaken in a common mild environment (simulation of a typical wheelchair basketball playing environment) under exercise conditions that were intended to simulate the duration and intensity of a typical competition half. our intent was to maintain high ecological validity throughout the investigation in order to make the results of this study inferable to an active sci population parsajsm vol 23 no. 1 2011 11 fig. 1. 35.5 36 36.5 37 37.5 38 38.5 t es ( °c ) stages (watt) sci ab 90705030 ab: n=8 sci: n=7 ab: n=7 sci: n=6 ab: n=7 sci: n=6 ab: n=7 sci: n=5 fig. 1. oesophageal temperature (tes) for sci and ab athletes during incremental exercise for arm-crank ergometry. sample size (n) is given for each stage that was completed. fig. 2. rectal temperature (trec) for sci wheelchair athletes and ab controls during incremental exercise for arm-crank ergometry. sample size (n) is given for each stage that was accomplished. fig. 2. 36.6 36.8 37.0 37.2 37.4 37.6 37.8 38.0 38.2 t re c (° c ) stages (watt) sci ab 30 50 70 90 ab: n=8 sci: n=7 ab: n=7 sci: n=6 ab: n=7 sci: n=6 ab: n=7 sci: n=5 fig. 3. upper body mean skin temperatures (msk-upper) for sci wheelchair athletes and ab controls during incremental exercise for arm-crank ergometry. sample size (n) is given for each stage that was accomplished. fig. 3. 30.0 31.0 32.0 33.0 34.0 35.0 36.0 37.0 stages (watts) t em p er at u re ( c ) sci ab 30 50 70 90 ab: n=7 sci: n=6 ab: n=7 sci: n=6 ab: n=7 sci: n=5 ab: n=8 sci: n=7 * * 12 sajsm vol 23 no. 1 2011 taking in wheelchair sports. it has been stated that individuals with sci have a compromised ability to thermoregulate, which can lead to magnified risk of thermal injury. 14 the purpose of this paper was to add to the understanding of the thermophysiology of heat storage in sci athletes. all subjects were matched based on fitness. three ab subjects had experienced training identical to the sci group participating on the same wheelchair basketball team and swimming teams (absolute vo2 peak is presented in table i). buresh et al. 15 suggested body mass and heat storage in ab athletes are significantly correlated. however, it is difficult to match these two populations (sci and ab) for body mass. as heat storage is a composite of both core temperature and skin temperature changes, for this study heat storage was compared between upper and lower body. there were lower heat storage values for the lower body compared with the upper body for both groups. however, there was no significant difference between groups. reduced heat storage for the lower body might have been due to the lack of muscular contraction in the lower body. therefore, there was little metabolic heat production. hslower was comprised of trec and msk (calf and thigh). there was no significant difference in the change in trec between the sci and ab groups. this could account for little differences detected between the two populations. both groups also demonstrated little difference for hsupper. greater hs for the upper body observed for both groups might have been due to the nature of the exercise mode. it could also be speculated that due to the sci athletes having a greater sweat response above their level of lesion. it has been demonstrated that at rest sci athletes have warmer skin temperature, which enables an earlier onset of sweating, and therefore earlier skin cooling when compared with ab athletes. 16 this upper-body adaptation to an impaired thermoregulatory ability might help compensate for the lower body inability to dissipate stored heat. msk temperature (fig. 3) for the upper body was higher than the lower-body skin temperature in sci. also, sci experienced higher mean skin temperature in both the upper and lower body than did the ab. this is in accordance with fitzgerald et al., 17 who noted that volunteers with sci who performed prolonged exercise at 24 25˚c experienced an increase of ~0.7˚c (in core temperature). it was suggested that the increase in msk was due to heat being generated from the working muscles, which was then transferred to the skin. heat from the insensate skin would not be able to be dissipated, thus this would result in an increase in skin temperature. one of the more extensively compiled research composites is that of sweat response between ab and sci individuals and between different levels of sci. 3,4,18 a reduction in whole-body sweating leads to greater increase in core temperature at rest, and a greater drive for sweating for a given environmental temperature. 19,20 the current investigation reported slightly elevated tes for sci athletes initially (37.1±0.4˚c) compared with ab (36.9±0.2˚c). similar responses were recorded for trec (sci = 37.2±0.5˚c and ab = 37.4±0.3˚c). however, it could be noted that the fluctuation in tes and trec could quite possibly be due to circadian variation or day-to-day variations. trec was late to increase in the sci athletes, only showing increase in the last two stages. this could possibly be due to a lag time experienced in trec measures, where rectal temperature measures have been shown to respond more slowly. 11 fig. 4. lower body mean skin temperature (msk-lower) for sci wheelchair athletes and ab controls during incremental exercise for arm-crank ergometry. sample size (n) is given for each stage that was accomplished. fig. 4. 29.0 30.0 31.0 32.0 33.0 34.0 35.0 36.0 37.0 30 50 70 90 stages (watt) t em p er at u re ( c ) sci ab ab: n=8 sci: n=7 ab: n=7 sci: n=6 ab: n=7 sci: n=5 fig. 3. 30.0 31.0 32.0 33.0 34.0 35.0 36.0 37.0 stages (watts) t em p er at u re ( c ) sci ab 30 50 70 90 ab: n=7 sci: n=6 ab: n=7 sci: n=6 ab: n=7 sci: n=5 ab: n=8 sci: n=7 * * fig. 5. mean heat storage for sci wheelchair athletes and ab controls during incremental exercise for arm-crank ergometry. *sci hsupper significantly greater than hslower (p<0.05) **ab hsupper significantly greater than hslower (p<0.05) fig. 6. heat storage per stage for sci wheelchair athletes (a) and ab controls (b) during incremental exercise for arm-crank ergometry. sample size (n) of athletes that completed the stage. fig. 6. 0.00 0.50 1.00 1.50 2.00 2.50 30 50 70 90 stages (watts) jx g -1 hsupper hslower n=7 n=6 n=6 n=5 a 0.00 0.50 1.00 1.50 2.00 30 50 70 90 stages (watts) jx g -1 upper lower n=8 n=7 n=7 n=7 b j. g1 j. g1 fig. 6. 0.00 0.50 1.00 1.50 2.00 2.50 30 50 70 90 stages (watts) jx g -1 hsupper hslower n=7 n=6 n=6 n=5 a 0.00 0.50 1.00 1.50 2.00 30 50 70 90 stages (watts) jx g -1 upper lower n=8 n=7 n=7 n=7 b sajsm vol 23 no. 1 2011 13 conclusion in summary, the current study examined the heat storage response during upper-body high-intensity exercise. results of this study suggest sci and ab athletes were similar with respect to thermoregulation during arm cranking. sci athletes tended to store slightly more heat in the lower body than ab athletes. both groups also demonstrated little difference for heat storage in the upper body. similarly, there was no significant difference observed for lower-body heat storage values. in a simulated gymnasium temperature environment it appears the matched groups demonstrated few meaningful differences in the current paradigm. future research should look at more sophisticated observation of heat transfer like thermography to better understand the dynamics of stored heat within this population during high-intensity activity. references 1. webborn n, price mj, castle pc, goosey-tolfrey vl. effects of two cooling strategies on thermoregulatory responses of tetraplegic athletes during repeated intermittent exercise in the heat. j appl phyiol 2005;98:2101-2107. 2. price mj, campbell ig. thermoregulatory responses of paraplegic and able-bodied athletes at rest, during exercise and into recovery. eur j appl physiol 1997;76:552-560. 3. price mj. thermoregulation during exercise in individuals with spinal cord injuries. sports med 2006;36(10):863-879. 4. guttman wl, silver j, wyndham ch. thermoregulation in spinal man. j physiol 1958;142:406-419. 5. jacobs pl, nash ms. exercise recommendations for individuals with spinal cord injury. sports med 2004;34(11):727-751. 6. price mj, campbell ig. thermoregulatory and physiological responses of wheelchair athletes to prolonged arm crank ergometry. inter j sports med, 1999;20:457-463. 7. pritchett rc, bishop pa, green jm, richardson m, zhang y, kerr kl. evaluation of artificial sweat in athletes with spinal cord injuries. eur j appl physiol 2010;109(1):125-131. 8. lenth rv. java applets for power and sample size [computer software]. http://www.stat.uiowa.edu/~rlenth/power (accessed 17 november 2006). 9. price mj, campbell ig. thermoregulatory responses of able bodied, upper body trained athletes to prolonged arm crank exercise in cool and hot conditions. j sports sci 2002;20:519-527. 10. o’conner dj, barnard te. continuing the search for wbgt clothing adjustment factors. appl occ env hygiene 1999;14:119-125. 11. gass gc, camp en, nadel er, et al. rectal and rectal vs. esophageal temperatures in paraplegic men during prolonged exercise. j appl physiol 1988;64(6):2265-2271. 12. havenith g, inoue y, luttikholg b, et al. age predicts cardiovascular, but not thermoregulatory, responses to humid heat stress. eur j appl physiol 1995;70:88-96. 13. ramanathan nl. a new weightings system for mean surface temperature of the human body. j appl physiol 1964;19:531-533. 14. bhambhan, y. physiology of wheelchair racing in athletes with spinal cord injury. sports med 2002:32;23-51. 15. buresh r, berg d, noble j. heat production and storage are positively correlated with measures of body size/composition and heart rate drift during vigorous running. res quart exerc sport 2005;76(3):267-275. 16. van beaumont, bullard rw. sweating: its rapid response to muscular work. sci 1963:141;643-646. 17. fitzgerald pi, sedlock da, knowlton rg. circulatory and thermal adjustments to prolonged exercise in paraplegic women. med sci sports exerc 1990;22:629-635. 18. hopman mte, van asten wn, oesburg b. blood flow changes below and above the spinal cord lesion during arm exercise in individuals with paraplegia. eur j appl physiol 1994:69;s26. 19. huckaba ce, frewin db, downey ja, tam, h-s, darling, rc, cheh hy. sweating responses of normal, paraplegic and anhidrotic subjects. arch phys med rehab 1976;57:268-274. 20. tam hs, darling rc, cheh hy, downey, aj. sweating response: a means of evaluating a set-point theory during exercise. j appl physiol 1978;45(3):451-458. introduction over the past two decades there have been significant changes in employer attitudes towards promotion of workplace health, wellness and physical fitness. 4 there is much evidence to support the economic and other benefits of worksite wellness programmes. 1,2,26,30 the benefits of these programmes include, among other spin-offs, improved productivity and worker morale, and reduction in absenteeism and staff turnover. the prevalence of chronic diseases in the workplace has escalated to a large extent as a result of poor lifestyle habits. 10,27,29 to effectively intervene, knowledge of lifestyle and factors affecting health must be known, e.g. physical activity levels, risk factors for chronic diseases, nutritional patterns and levels of stress. the monitoring of activity levels and total energy expenditure (tee) of daily activities has become more important in order to have an impact on chronic disease prevention and management.18 physical activity measurement is not only health promotional in that it creates awareness for individuals involved in exercise programmes, but is also prescriptive in terms of quantifying the required exercise ‘dose’.13 physical activity is therefore one of the cornerstones of any lifestyle management programme; however, the measurement of energy expenditure and physical activity levels has not always being accurate or objective. such measurement has become much easier with a recently developed device for the assessment of tee and physical activity levels (body media sensewear pro armband®). the accuracy of the device has been confirmed and corroborated by jakicic et al.16 and malavolti et al.21,22 with advances in the standardisation of surveillance methodology and the introduction of more objective measures of physical activity energy expenditure and inactivity,36 the relationships between physical activity, inactivity, fitness and the prevalence of chronic diseases have become better understood.5,6,9,35 the study presented here was designed to accurately measure the components of, and contributors to, daily energy expenditure in a cohort of corporate white-collar workers who had previously been original research article energy expenditure in office workers with identified health risks abstract objective. to measure the daily energy expenditure in employees previously identified as having ≥2 risk factors for chronic disease, and to identify potential risk-reducing interventions for implementation within or outside the workplace. design. a total of 122 employees with ≥2 risk factors for chronic disease identified in an in-house screening programme were invited to participate in a 6-month health management programme. physical assessments included anthropometric measurements, blood pressure, blood glucose and cholesterol estimations, and bicycle ergometry. participants were invited to wear a ‘metabolic armband’ (body media sensewear pro armband®) for 6 days. metabolic measures included active and total energy expenditure (aee, tee), and daily met levels (metabolic equivalents expressed as kcal/kg/hour). differences were explored between genders, and relationships sought between energy expenditure, lifestyle and anthropometric data. setting. a corporate working environment. all measures and assessments were carried out in the in-house fitness facility. interventions. the health management programme involved physical assessments and personalised weight and activity management plans. main outcome measures. tee per day, duration and quantification of physical activity, mets, aee, number of steps per day and body position recording. relationships were explored between the latter and anthropometric measures such as body mass index (bmi) and percentage body fat. result. altogether 53 (43%) of the eligible subjects volunteered for the 6-month programme and 49 enrolled for the metabolic armband study. the males were more active than the females, but both had bmi and body fat estimates that categorised them as overweight to obese. mets and aee were positively correlated with duration of exercise rather than intensity, and negatively correlated with bmi. in a stepwise regression analysis for the total group 77% of the variance in met levels was accounted for correspondence: professor y coopoo medical school wits 2050 e-mail: yoga.coopoo@wits.ac.za mobile: 083 415 7466 yoganathan coopoo (d phil, facsm) demitri constantinou (mb bch, bsc med hons, ffims) alan d rothberg (mb bch, fcpaed, phd) centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg by per cent body fat and steps per day. multivariate analysis by gender (with per cent body fat as the dependent variable) suggested that males would have to increase the duration of vigorous exercise in order to reduce body fat, while females would benefit from sitting less, sleeping more, and increasing the duration of moderate exercise. conclusion and clinical relevance. in a self-selected sample involving motivated individuals, the sensewear® armband provided information that would be useful in directing further research in women, focusing on sleeping pattern and moderately increasing activity levels. 40 sajsm vol 20 no. 2 2008 pg40-48.indd 40 8/11/08 8:49:18 am assessed as having ≥2 risk factors for chronic disease by means of an in-house risk assessment process. the employer had expressed an interest in knowing how many at-risk employees would act on the information, and the researchers had an interest in utilising the information gained from a range of assessments in order to develop innovative health and wellness interventions for implementation within and/or outside the workplace. methods this study was part of a larger study in which 122 ‘at-risk’ employees of a medium-sized corporate entity in the financial services sector were invited to participate in a 6-month programme that involved physical assessments and personalised weight and activity management plans. these employees were a sub-set of a group of 621 that had previously participated in an in-house health and wellness assessment that was mainly based on medical and lifestyle history (e.g. hypertension, diabetes, hyperlipidaemia, cigarette smoking, alcohol consumption, poor diet and psychosocial stress). all of the 122 invitees had ≥2 risk factors. those who chose to participate underwent basic physical and medical assessment (height, weight, blood pressure, blood glucose and cholesterol, bicycle ergometry), and a number of anthropometric assessments. skinfold thickness (triceps, supra-iliac and mid-thigh) was measured to the nearest millimetre using the lange skinfold calliper and results were utilised to calculate percentage body fat.14 waist and hip circumferences were measured using a plastic dressmaker’s tape20 and the waist-to-hip ratio was calculated. the body mass index (bmi) was calculated using the measurements of height and weight according to the bray formula.7 predicted maximum oxygen uptake (vo2max) was estimated using the ymca protocol.11 standardised testing procedures were followed as defined in the american college of sports medicine (acsm) guidelines.3 all participants were asked to consider wearing a body media sensewear pro armband® to supplement and complement the other measures. this device was used to measure tee and its parameters, and was worn on the triceps of the right arm for an average of 18 hours per day for a period of 6 days. the multi-sensor armband is worn continuously for a defined period of time in order to quantify metabolic physical activity and calculate energy expenditure in free-living individuals. physiological body signals are gathered from five sensors (for measurement of skin temperature, near body temperature/heat flux, galvanic skin resistance, and accelerometry). sophisticated software accumulates and translates the data into energy expenditure and activity-recognition patterns in order to calculate energy consumption based on predetermined algorithms. parameters measured and calculated by the device include total (daily) energy expenditure (expended kilocalories), duration and quantification of physical activity, mets (metabolic equivalents expressed as kcal/kg/hour), active energy expenditure (aee), number of steps per day, body position recording, i.e. standing, sitting v. supine and sleeping.21 by convention, the physical activity levels were set to record above the sedentary threshold (3.0 mets) which is equivalent to a light moderate walk. the sedentary classification was between 0 and 3 mets, while at the other extreme, the vigorous and very vigorous mets classifications were at 6 9 and >9 mets respectively. descriptive and inferential statistical methods mere used to analyse the data within and between genders. variances were shown by the calculation of the means and standard deviations. relationships were determined using multivariate analyses. statistical significance was set at p≤0.05. all analyses were performed using the texasoft sda version 6 professional edition package. the study was approved by the institutional committee for research on human subjects. all subjects signed informed consent. results only 53 (43%) of the 122 employees with identified health risks signed consent to participate in the 6-month project. unfortunately table i. morphological characteristics of the group (n=49) parameters females males difference mean(sd) mean(sd) (p values) n=35 n=14 age (yrs) 33.3(6.3) 30.7(3.5) 0.07 mass (kg) 78.6(22.4) 84.8(15.8) 0.28 height (cm) 162(6) 178(7) <0.0001 bmi (m 2 /kg) 29.4(7.3) 27.1(4.2) 0.16 waist (cm) 83.9(14.9) 89.9(11.3) 0.13 hip (cm) 110.2(15.1) 101.2(7.9) <0.01 waist:hip ratio 0.76(0.08) 0.88(0.1) <0.01 % body fat 28.9(8.5) 19.4(8.4) 0.002 table ii. daily metabolic and activity characteristics of the group (n=49) females males difference mean(sd) mean(sd) (p values) n=35 n=14 total energy expenditure (kcal/day) 1 974(271) 2 552(581) 0.003 mets (kcal.kg -1 .hr -1 ) 1.37(0.5) 1.64(0.5) 0.10 active energy expenditure (kcal/day) 364(243) 704(405) <0.01 physical activity duration (min) 69(49) 101(61) 0.1 moderate exercise (min) (3 6 mets) 62(40.4) 92(47) 0.045 vigorous exercise (min) (6 9 mets) 8.4(6.4) 15.1(13.9) 0.1 very vigorous exercise (min) (≥9 mets) 4.9(5.5) 8.5(7.8) 0.13 predicted vo2max (ml.kg -1 .min -1 ) 22(6.6) 35(11.7) <0.001 steps (no.) 5 914(2 058) 8 141(3 200) 0.03 sedentary (min) 1 054(126) 1 147(389) 0.9 sleeping (min) 331(82) 292(61) 0.08 sajsm vol 20 no. 2 2008 41 pg40-48.indd 41 8/11/08 8:49:18 am the employer resisted efforts to obtain information from those who declined the invitation to participate, but it is likely that the nonparticipants included some employees who had elected to pursue health-promoting activities outside the workplace, as well as others who had chosen to ignore their assessed risk status. forty-nine of the 53 volunteered to wear the armbands, and this component was carried out during the first few weeks of the overall study. as such it is likely that participants’ enthusiasm for the project and motivational levels were still high. thirty-five subjects were female and 14 male. table i represents the morphological characteristics of the participants. men were significantly taller than women, had narrower hips, lower percentage body fat and higher waist:hip ratios than women. these findings are in line with expected differences between genders; however, it should be noted that average bmi and percentage body fat were in the overweight range for men and bordering on obese for women.12 the metabolic and activity characteristics of the study population are shown in table ii, and again the results are largely as expected. women expended less energy than men (walked and exercised less), and as a consequence thereof demonstrated significantly lower tee, aee and predicted vo2 max. most likely because of the relatively small sample size, the inter-gender difference in mets did not reach significance. differences in vigorous and very vigorous exercise were also not significant because of the relatively small number of subjects in both groups who engaged in the higher levels of exercise. table iii shows that for the total group, aee and/or mets correlate best with duration of exercise in this study, not with intensity, potentially an important point in devising strategies for further intervention. results also showed an inverse relationship between bmi and both duration of physical activity and aee. the latter correlations introduce the question of cause and effect, i.e. do overweight subjects exercise less and consequently have lower measures of activity, or is a higher bmi simply the result of less physical activity? in a stepwise regression analysis for the total group, 77% of the variance in met levels was accounted for by percentage body fat (p<0.001) and the number of steps taken daily (p<0.006), with none of the other parameters reaching statistical significance. further analysis was then mainly directed towards interrogating relationships with the percentage of body fat. in females, 70% of the variance in percentage body fat was accounted for by moderate exercise (p<0.001), time spent sitting down (p<0.049), and time spent sleeping (p<0.001). notably, the latter correlation was negative, i.e. the less time spent sleeping, the higher the percentage body fat. the same analysis in the group of males showed only a significant relationship between very vigorous exercise and percentage body fat (accounting for 56% of the variance). discussion the first point to be noted is the at-risk employees’ relatively low uptake of the offer to pursue the finding that they were candidates for long-term consequences of medical or lifestyle diseases. as already stated, the employer was reluctant to permit further interrogation of this point, so it is not clear how many of the non-responders had actually taken note of their risk status and how many had chosen to ignore it. as for the employees who chose to take action on the basis of their risk status, one must accept that they represent a small and biased sample, and any recommendations that are made can therefore only apply to and be tested on similar subjects. noting this fact, both males and females in this study had bmi and percentage body fat values that were categorised as overweight, with the females’ scores bordering on obesity (29.4±7.3). in a classification of disease risk based on bmi (25.0-29.9), both sexes in this study are at increased risk for chronic conditions such as diabetes, hypertension, and cardiovascular disease.17 overweight women carry greater risk for cardiovascular disease than those with normal body mass indices.32 pedesen has indicated that chronic disease and premature mortality are not only related to obesity, but also to physical inactivity.25 it is therefore also important to explore activity and energy relationships, because regular physical activity has healthpromoting effects that go beyond the effects on weight control. in an at-risk group such as the one in this study, development of an exercise and/or lifestyle intervention programme may retard or reduce the risk of long-term consequences.23,24,33 the ability to accurately measure energy expenditure in free-living individuals is always a challenge; however, with the introduction of the sensewear® armband, which is a non-invasive device that accurately captures physiological body signals, data can subsequently be downloaded to provide information on lifestyle, physical activity patterns, and movement and sleep profiles. the current study measured tee, aee, mets, number of steps per day, physical activity intensity and duration, and time spent sitting and lying/sleeping. results showed that tee was significantly higher in males (2 552 kcal/day) compared with females (1 974 kcal/day). resting metabolic rate represents the amount of energy expended under resting conditions and typically accounts for about 60 70% of tee.18 the thermic effect of food represents ±10% of tee, while the physical activity energy expended forms the third component of tee.18 this latter component is most variable, as individuals choose to be active or not. the resulting effect of physical activity may therefore be small or can contribute significantly towards tee.18,28 in the present study aee represented 18.4% of tee in females and 27.6% in males (p<0.001), with the difference coming mainly from the greater number of steps taken by males per day (8 141 v. 5 914) and the greater duration of moderate exercise (92 v. 62 minutes/day). these latter figures for daily exercise are relatively high, perhaps explained by the fact that we were measuring during the early part of the project while gym attendance and adherence to the programme were at optimal levels. the average sedentary person expends between 300 and 800 calories per day in physical activity from informal, unplanned types of movement to more structured exercise programmes. this may vary from person to person and according to differences in body mass. jakicic et al.15 indicated that increasing exercise duration to 200 300 minutes per week facilitates long-term maintenance of weight loss. the acsm and the american heart association (aha) have recently revised the exercise guidelines for optimal health, concluding that exercise should be done at a moderate to high intensity for 3 5 days of the week in order to derive greatest benefit.12 in this study the intensity of activity was lower in females as compared with males, and active energy expenditure and mets correlated better with duration of exercise than with intensity. mets are calculated and averaged over a 24-hour period as an index of an individual’s metabolic ‘intensity’, i.e. whether the person is moderately active or lives life at a slow pace. in the present study the met levels for men and women were 1.64 and 1.37 kcal/kg/ h respectively. lifestyles with met levels between 1.0 and 1.5 are considered to be predominantly sedentary, while values ranging table iii. correlations between active energy expenditure, mets, physical activity duration and body mass index correlations r 2 p value active energy expenditure/mets v. 0.94/0.85 <0.0001 physical activity duration active energy expenditure v. body mass index -0.58 <0.0001 physical activity duration v. body mass index -0.71 <0.0001 42 sajsm vol 20 no. 2 2008 pg40-48.indd 42 8/11/08 8:49:19 am between 1.51 and 2.0 are typically regarded as representing light to moderate activity.18 it would appear that the activity of the females in this study should be increased in intensity to at least moderate levels, thereby affording greater physiological benefits. the predicted oxygen consumption (vo2max) for females further illustrates that the intensity of physical activity is low for the females (22 ml/kg/min) as compared with the males (35 ml/kg/min). results also showed an inverse relationship between bmi and both duration of physical activity and aee. as already stated, the latter correlations lead one to at least consider the question of what is cause and what is effect, i.e. do overweight subjects exercise less and consequently have lower measures of activity, or is a higher bmi simply the result of less physical activity? jakicic et al. believe that it is important to know how much exercise is required to retard unhealthy weight gain in adults.17 observational evidence shows that in order to prevent weight gain, physical activity must be moderate to vigorous in intensity, and this intensity will also confer an increased fitness.12,16 the body of evidence therefore appears to support the notion that the bmi follows the level of activity, rather than the converse and, in fact, in attempts to motivate participants to lose weight in this particular study, discussions took place at personal and group level that were focused on the usual triad of eating less, a healthier diet, and more physical activity. factors determining met levels were interrogated for males and females, and analysis showed that percentage body fat was significantly correlated. for males in this study it appeared that body fat would respond best to vigorous exercise, but it should be noted that the males were already at moderate levels of activity, so this result is as expected. for females, however, there was an inverse relationship between body fat and increasing levels of activity and/or reduction of inactivity (spending less time sitting, sleeping more and increasing the amount or duration of moderate exercise). telford (2007) believes that physical activity and cardiorespiratory fitness may improve energy balance and prevent obesity, reducing risk for chronic disease.34 it has been further shown that regular exercise induces favourable metabolic changes in muscle and adipose tissue, thereby promoting the use of fat for energy as opposed to storing it.18 in terms of the finding of the inverse relationship between percentage of body fat and time spent sleeping, females in this study slept for an average of 5½ hours per 24 hours. a recent study by chaput et al. proposed an optimal relationship between sleep duration and regulation of body weight, with the ideal sleep duration around 7 8 hours. 8 the researchers noted that short sleep duration predicts an increased risk of being overweight or obese, and that this is related to reduced circulating leptin levels relative to what is predicted by fat mass. sleep duration is a modifiable risk factor, hence these findings may be of importance to the clinical management and treatment of obesity. ko et al. (2007) would likely concur since they showed an association between obesity, reduced sleeping hours (and long working hours) in chinese workers.19 while the body of evidence is accumulating in favour of this counter-intuitive finding, more research is probably required in order to determine the mechanisms responsible for this clinical phenomenon and the role of sleep management in the treatment of overweight and obesity. meanwhile it is the intention of the researchers involved in the study presented here to follow up with an intervention that is targeted at overweight females and based on the results presented above. the intervention will focus less on modification of diet, and more on sitting less each day, walking more, and either going to bed earlier or waking later each day. conclusion as with many corporate health and wellness programmes, many employees with risk factors for chronic disease do not avail themselves of remedial opportunities. in this study, participants whose physical, metabolic and activity parameters were measured were shown to be in the overweight to obese range. men were more active than women. a potentially exciting weight reduction intervention was identified for women that would involve a moderate increase in activity and slight increase in the duration of sleep per night. references 1. aldana sg, greenlaw rl, diehl ha, salberg a, merrill rm, ohmine s. the effects of a worksite chronic disease prevention program. j occup environ med 2005; 47: 558-64. 2. aldana sg, merrill rm, price k, hardy a, hager r. financial impact of a comprehensive multisite workplace health promotion program. prev med 2005; 40: 131-37. 3. american college of sports medicine. guidelines for exercise testing and prescription. 7th ed. philadelphia: lippincott williams and wilkins, 2006. 4. atlantis e, chow c-m, kirby a, fiatarone, singh ma. worksite intervention effects on physical health: a randomized controlled trial. health promot int 2006; 21(3):191-200. 5. blair sn, cheng y, holder js. is physical activity or physical fitness more important in defining health benefits? med sci sports exerc 2001; 33(6 suppl):s379-99; discussion s419-20. 6. bouchard c. physical activity and health: introduction to the dose-response symposium. med sci sports exerc 2001; 33(6): 347-50. 7. bray ca. obesity: definition, diagnosis and disadvantages. med j aust 1985;142: 52-5. 8. chaput j-p, despres j-p, bouchard c, trembley a. sleep duration is associated with reduced leptin levels and increased adiposity: results from the quebec family study. obesity 2007;15(1): 253-61. 9. ekelund u, franks pw, sharp s, brage s, wareham nj. increase in physical activity energy expenditure is associated with reduced metabolic risk independent of change in fatness and fitness. diabetes care 2007; 30(8): 2101-6. epub 2007 may 29. 10. goetzel rz, anderson dr, whitmer rw, ozminkowski rj, dunn rl, wasserman j. the relationship between modifiable health risks and health care expenditures. an analysis of the multi-employer hero health risk and cost database. j occup environ med 1998; 40: 843-54. 11. golding la, myers cr, sinning we, eds. y’s way to physical fitness, 3rd ed. champaign, illinois: human kinetics, 1989. 12. haskell wl, lee im, pate rr, et al. physical activity and public health: updated recommendations for adults from the american college of sports medicine and the american heart association. med sci sports exerc 2007; 39(8):1423-34. 13. heyward vh. principles of assessment, prescription and exercise programme adherence in advanced fitness assessment and exercise prescription. champaign, illinois: human kinetics, 2006. 14. jackson as, pollock ml. research progress in validation of clinical methods of assessing body composition. med sci sports exerc 1984;16(6): 606-15. 15. jakicic jm. the role of physical activity in the prevention and treatment of body weight gain in adults. j nutr 2002;132: 3826s-29s. 16. jakicic jm, marcus m, gallacher k i, et al. evaluation of the sensewear pro armband to assess energy expenditure during exercise. med sci sports exerc 2004; 36(5): 897-904. 17. jakicic m, clark r, coleman e, et al. american college of sports medicine’s position stand: appropriate intervention strategies for weight loss and prevention of weight regain for adults. med sci sports exerc 2001; 33: 2145-56. 18. kiem nl, blanton ca, kretsch mj. america’s obesity epidemic: measuring physical activity to promote active lifestyles. j am diet assoc 2004; 104:1398-409. 19. ko gtc, chan jcn, wong pts, et al. association between sleeping hours, working hours and obesity in hong kong chinese: the ‘better health for better hong kong’ health promotion campaign. int j obesity 2007; 31: 254-60. 20. lohman tg, roche af, martoveli r, eds. anthropometric standardization reference manual. champaign, illinois: human kinetics, 1988. 21. malavolti m, pietrobelli a, dugoni m, et al. a new device for measuring resting energy expenditure (ree) in healthy subjects. nutr metab cardiovasc dis 2007; 17(5): 338-43. 22. malavolti m, pietrobelli a, dugoni m, et al. a new device for measuring daily total energy expenditure (tee) in free living individuals. int j body comp res 2005; 3: 63. sajsm vol 20 no. 2 2008 43 pg40-48.indd 43 8/11/08 8:49:19 am 23. melanson kj, mcinnis kj, rippe jm, blackburn g, wilson pf. obesity and cardiovascular disease risk: research update. cardiol rev 2001; 9(4): 202-7. 24. nguyen hq, ackermann rt, berke em, et al. impact of a managed-medicare physical activity benefit on health care utilization and costs in older adults with diabetes. diabetes care 2007; 30: 43-8. 25. pedesen bk. body mass index: an independent effect of fitness and physical activity for all cause mortality. scand j med sci sports 2007; 17(3); 196-204. 26. pelletier kr. a review and analysis of the clinical and cost-effectiveness studies of comprehensive health promotion and disease management programs at the worksite: update vi 2000-2004. j occup environ med 2005; 47: 1051-58. 27. pelletier b, boles m, lynch w. change in health risks and work productivity over time. j occup environ med 2004; 46: 746-54. 28. ravussin e, bogardus c. a brief overview of human energy metabolism and its relationship to essential obesity. am j clin nutr 1992; 55: 242s45s. 29. rodgers a, ezzati m, van der hoorn s, lopez ad, ruey-bin l, murray cjl. comparative risk assessment collaborating group. distribution of major health risks: findings from the global burden of disease study. 2004; plos med 1(1): e27. 30. serxner sa, gold db, grossmeier jj, anderson dr. the relationship between health promotion program participation and medical costs: a dose response. j occup environ med 2003; 45: 1196-200. 31. shephard rj. a critical analysis of worksite fitness programmes and their postulated economic benefits. med sci sports exerc 1992; 24; 354-70. 32. song y, manson je, meigs jb, ridker pm, buring je, liu s. comparison of usefulness of body mass index versus metabolic risk factors in predicting 10-year risk of cardiovascular events in women. am j cardiol 2007; 100(11): 1654-8. 33. stein ad, shakour sk, zuidema ra. financial incentives, participation in employer-sponsored health promotion, and changes in employee health and productivity: healthplus health quotient program. j occup environ med 2000; 42: 1148-55. 34. telford rd. low physical activity and obesity: causes of chronic disease or simply predictors? med sci sports exerc 2007; 39(8):1233-40. 35. wang g, pratt m, macera ca, zheng zj, heath g. physical activity, cardiovascular disease, and medical expenditures in us adults. ann behav med 2004; 28(2): 88-94. 36. wareham nj, rennie kl. the assessment of physical activity in individuals and populations: why try to be more precise about how physical activity is assessed? int j obes relat metab disord 1998; suppl (2): s30-8. introduction exercise testing with respiratory gas collection (rgc) and analysis during indirect calorimetry has long been a routine procedure in exercise physiology laboratories, enabling the simultaneous measureoriginal research article abstract objective. despite their widespread use in exercise testing, few data are available on the effect of wearing respiratory gas collection (rgc) systems on exercise test performance. industrial-type mask wear is thought to impair exercise performance through increased respiratory dead space, flow resistance and/or discomfort when compared with rgc facemasks, but whether performance decrements exist for rgc facemask wear versus non-wear is unclear. the objective of this study was to evaluate the difference in incremental exercise test performance with and without a rgc system. incremental exercise test performance with and without a respiratory gas collection system correspondence: james r clark institute for sport research lc de villiers sport centre university of pretoria 0002 pretoria south africa tel: +27 12 420 6033 fax: +27 12 420 6099 e-mail: jimmy.clark@up.ac.za james r clark (bsc (hons), (ba (hons)) institute for sport research, department of biokinetics, sport and leisure sciences, university of pretoria design. twenty moderately active males (age 21.0 ± 1.9 years; vo2peak 55.9 ± 3.0 ml∙kg -1∙min-1) performed two progressive treadmill tests to volitional exhaustion. in random order subjects ran with (mask) or without (no-mask) a rgc facemask and flow sensor connected to a gas analyzer. descriptive data (mean ± sd) were determined for all parameters. the wilcoxon signed rank test for paired differences was used to assess mean differences between mask and no-mask conditions. results. exercise time to exhaustion, peak treadmill speed, peak blood lactate concentration, peak heart rate and rating of perceived exertion (rpe) were not different (p>0.05) between mask and no-mask conditions. conclusions. incremental exercise test performance is not adversely affected by rgc and analysis equipment, at least in short duration progressive treadmill exercise. respiratory gas analysis during exercise testing for diagnostic, performance assessment or training prescription purposes would appear to be unaffected by rgc systems. 44 sajsm vol 20 no. 2 2008 pg40-48.indd 44 8/11/08 8:49:20 am original research sajsm vol. 25 no. 2 2013 51 background. legend has it that endurance athletes who develop plantar foot pain during long-distance running frequently experience an eventual relief of pain due to a transient neuropraxia brought on by continued activity. objective. to evaluate the nature of this legend, we assessed long-distance runners for the presence of sensory deficits before and after completion of an ultramarathon, expecting to find an induced neuropraxia and abnormal sensory results. methods. twenty-five adult participants of an ultramarathon were evaluated prior to their 50/100 km run and again upon completion of the race. neurosensory testing was performed using a 10 g monofilament at 4 locations on each foot and a 128 hz tuning fork at one location on each foot. the same techniques were used prior to, and at conclusion of the race. results. we detected no neuropraxia or sensory deficits in any participant, despite reports by the same subjects that they had experienced the phenomenon during the race. while runners commonly report losing sensation in their feet during long runs, we were unable to demonstrate any sensory deficit with simple field-based testing. conclusion. we believe that there is room for additional research to be performed using more sensitive means of neurosensory evaluation. s afr j sm 2013;25(2):51-52. doi:10.7196/sajsm.468 the legend of plantar neuropraxia in long-distance athletes d s kellogg,1 md; j joslin,2 md 1 department of emergency medicine, johns hopkins university, baltimore, maryland, usa 2 department of emergency medicine, state university of new york, upstate medical university, syracuse, new york, usa corresponding author: j joslin (joslinj@upstate.edu) legend has it, and anecdotal reports reinforce that endurance athletes who develop plantar foot pain during long-distance running events will frequently experience an eventual relief of pain due to a transient neuropraxia brought on by continued activity. does this transient neuropraxia, which seems to occur during, or immediately after endurance running, represent an early symptom of the development of permanent neuropathy, or is it a benign and transient phenomenon? previous research has considered permanent neurological deficits in runners, ranging from minor changes in sensory thresholds[1] to entrapment neuropathies.[2,3] a growing body of literature has investigated and reviewed these changes in pain perception among runners.[4-6] even though there is mention of acute neurosensory deficits during a race, in scholarly literature[1,2] and among athletes, no studies have rigorously demonstrated it. using a standardised field technique utilising monofilament testing, we sought to expand on previous research on neurosensory changes in athletes and discover if a detectable, objective neuropraxia was induced in ultramarathon runners on race day. methods the study was reviewed and approved by the state university of new york upstate medical university institutional review board. runners participating in the 2010 green lakes endurance runs single-day 50/100 km trail races, were asked to participate in the study. study participation was not a requirement for race participation, or to receive medical care during the race. all participants were aged ≥18 years and provided informed, written consent prior to study participation. participants were given a short questionnaire surveying demographic and running-related information. prior to the race, participants’ feet were visually inspected for the presence of calluses and blisters. two accepted methods for evaluating diabetic neuropathy[7] were then used to evaluate vibratory and lighttouch sensation. first, a 128 hz tuning fork was placed on the dorsum of the great toe; the test was considered positive if the participant could not feel the vibration of the tuning fork while the examiner could, and negative otherwise. second, a 10 g monofilament was touched to the plantar aspect of the great toe, and the plantar aspects of the first, third, and fifth metatarsophalangeal joints; the test was considered positive if the participant was unable to feel the monofilament touching the foot when the examiner applied just enough pressure to cause the monofilament to bend. the same evaluation of visual inspection, vibratory, and light-touch sensation was repeated on participants at either the completion of the race, or the time of discontinuation of the race. results of both evaluations were matched by participant and compared for analysis. results in total, 31 subjects (17 men, 14 women; age range 24 66 years) consented to study participation and completed the questionnaire; 30 participated in the initial neurosensory testing, and 26 in the postrace testing. one participant had post-race testing performed but not pre-race testing; therefore, only 25 participants were compared longitudinally. none had a diagnosed history of conditions that might have caused permanent neurosensory deficits. interestingly, and germane to our investigation, 15 participants (48%) reported having previously experienced neuropraxia associated with running. none of the participants (0/25; 0%) was found to have a difference in neurosensory test results when comparing preand post-race evaluation; none (0/30; 0%) was found to have a deficit in vibration mailto:joslinj@upstate.edu 52 sajsm vol. 25 no. 2 2013 sensation prior to the race; and none (0/26; 0%) was found to have impairment at re-evaluation post race. a few participants demonstrated deficits in light touch at one or more locations during pre-race evaluation (4/30; 13%); however, they did not return for follow-up testing at the conclusion of the race. the only significant, but not surprising difference between preand post-race evaluations was that more runners had blisters after the race (13/26; 50%) than before the race (2/30; 6.7%). discussion we found no evidence of neuropraxia in our subjects. no prior reports have demonstrated transient plantar neuropraxia in endurance athletes. we therefore conclude that plantar neuropraxia among endurance athletes is either a somatoform manifestation, or was simply not detected by our evaluation. almost half of our participants reported subjective neuropraxia at some point during their running careers. indeed, some stated that they experienced this during the race on the day of the study. despite these relevant experiences, none was objectively found to have a loss of sensation on post-race testing. perhaps runners reporting these feelings are experiencing a somatoform phenomenon. other investigations evaluating pain perception among endurance athletes have shown that the fastest runners in an ultramarathon experienced a moderate reduction in pain perception immediately after a race.[5] runners may misinterpret decreased pain sensation as decreased overall sensation. it is also possible that athletes do develop a real sensory deficit, but that the act of sitting down and removing shoes to have testing performed may ‘cure’ the deficits. finally, it is possible that plantar neuropraxia among endurance athletes is real, but that our simple testing method was too insensitive to detect it. to allow for rapid field evaluation and encourage maximum study participation, we performed neurological testing methods typically used to assess diabetic neuropathy. such techniques may not be sensitive enough to detect more subtle deficits encountered by runners. in the future, methods that may increase sensitivity for minor changes in perception include using a thinner monofilament (1 g) and additional modalities of sensory testing, to elucidate whether any neuropraxia that may exist affects nerve fibre types differentially. additionally, our study had a small sample size, and examined participants at only one event. perhaps different race conditions – e.g. running on the pavement v. dirt trails, changes in heat and humidity, etc., or a different athlete population – might have changed our findings. it is unfortunate that the only participants with pre-race deficits did not return for post-race testing, as their sensory changes may have been more pronounced. if transient plantar neuropraxia is a real phenomenon, what is the likely mechanism? one mechanism proposed in the literature involves tight running shoes which may lead to ischaemia of the nerves to the foot.[2] prior studies have pointed to the repetitive trauma of running as a cause of plantar neuropathy.[3,8] medial plantar neuropathy (jogger’s foot), neuropathic pain over the course of the medial plantar nerve,[3] is a well-known phenomenon that occurs during and after exercise. perhaps transient plantar neuropraxia is merely a minor form of, or a precursor to this condition. or, maybe it is a side-effect of the betterstudied phenomenon of increased pain thresholds among athletes.[4-6] if the phenomenon of plantar neuropraxia truly exists, and if its effects are not benign, we could potentially see more neurological sequelae as ultra-running, and other endurance sports requiring prolonged-time walking, hiking or running, become more popular. further research is needed to explore what sort of damage transient and permanent athletes may be causing to the nerves in their feet and what mechanism may be the cause. references 1. dyck pj, classen sm, stevens jc, o'brien pc. assessment of nerve damage in the feet of long-distance runners. mayo clin proc 1987;62(7):568-572. [http://dx.doi. org/10.1016/s0025-6196(12)62294-0] 2. mckean ka. neurologic running injuries. neurol clin 2008;26:281-296. [http:// dx.doi.org/10.1016/j.ncl.2007.11.007] 3. peck e, finnoff jt, smith j. neuropathies in runners. clin sports med 2010;29:437547. [http://dx.doi.org/10.1016/j.csm.2010.03.002] 4. droste c, greenlee mw, schreck m, roskamm h. experimental pain thresholds and plasma beta-endorphin levels during exercise. med sci sports exerc 1991;23(3):334342. [http://dx.doi.org/10.1249/00005768-199103000-00012] 5. hoffman md, lee j, zhao h, tsodikov a. pain perception after a running a 100mile ultramarathon. arch phys med rehabil 2007;88(8):1042-1048. [http://dx.doi. org/10.1016/j.apmr.2007.05.004] 6. janal ma. pain sensitivity, exercise and stoicism. j r soc med 1996;89:376-381. 7. singh n, armstrong dg, lipsky ba. preventing foot ulcers in patients with diabetes. jama 2005;293(2):217-228. [http://dx.doi.org/10.1001/jama.293.2.217] 8. oh sj, meyer rd. entrapment neuropathies of the tibial (posterior tibial) nerve. neurol clin 1999;17(3):593-615. [http://dx.doi.org/10.1016/s0733-8619(05)70154-7] http://dx.doi.org/10.1016/s0025-6196 http://dx.doi.org/10.1016/s0025-6196 http://dx.doi.org/10.1016/j.ncl.2007.11.007] http://dx.doi.org/10.1016/j.ncl.2007.11.007] http://dx.doi.org/10.1016/j.csm.2010.03.002] http://dx.doi.org/10.1249/00005768-199103000-00012] http://dx.doi.org/10.1016/j.apmr.2007.05.004] http://dx.doi.org/10.1016/j.apmr.2007.05.004] http://dx.doi.org/10.1001/jama.293.2.217] http://dx.doi.org/10.1016/s0733-8619 introduction acute and chronic musculoskeletal soft-tissue injuries are common during participation in physical activity.1 multiple extrinsic and intrinsic risk factors are implicated in the aetiology of these complex injuries.2,3 in two specific injuries, anterior cruciate ligament (acl) ruptures and chronic achilles tendinopathy, genetic components have been identified as intrinsic risk factors. among the genetic risk factors identified, the co5a1 bstui restriction fragment length polymorphism (rflp) has been associated with both chronic achilles tendinopathy and acl ruptures.3-5 the cc genotype of the col5a1 bstui rflp was significantly over-represented in asymptomatic participants compared with those with chronic achilles tendinopathy – both in south african4 and australian3 populations. a similar finding was reported when female participants with acl ruptures were compared with asymptomatic female controls.5 all control groups in these studies were matched for physical activity and physiological characteristics. these data suggest that individuals with a cc genotype are protected, despite the particular load and/or external forces applied to their musculoskeletal soft tissues. however, the cc genotype of the col5a1 bstui rflp was not over-represented in male subjects with acl ruptures compared with asymptomatic male controls.5 owing to the reported increased risk of acl ruptures among females, the acl study analysed males and females separately. the previous two achilles tendinopathy studies only analysed males and females as one group. interestingly, the cc genotype frequency of the male asymptomatic participants of the acl study was distinctly lower than the cc genotype frequencies of the asymptomatic control cohorts in which the cc genotype was over-represented.3-5 furthermore, the male asymptomatic participants of the acl study were approximately 10 years younger than the asymptomatic control groups in the previous two achilles tendinopathy studies. original research article the col5a1 gene and musculoskeletal soft-tissue injuries abstract background. it has been shown that there is an association between various genetic variants and achilles tendon injuries as well as anterior cruciate ligament (acl) ruptures. among other variants the bstui restriction fragment length polymorphism (rflp) within the col5a1 gene has been shown to be over-represented in asymptomatic participants when compared with those with chronic achilles tendinopathy, and in asymptomatic female participants when compared with those with acl ruptures. the male asymptomatic control participants in the acl study, which were 10 years younger than previously investigated cohorts, had a distinctly different genotype frequency. aim. the aim of this study was therefore to determine whether the distribution of the col5a1 bstui rflp in the combined asymptomatic participants without any known history of tendon injuries is age dependent, particularly among males. results. when the 265 male asymptomatic participants from all studies were pooled and divided into age-group tertiles, there was a significant linear increase in the cc genotype frequency (p=0.032) among the male age groups, with the youngest group having the lowest frequency (cc genotype frequency, 13%) and the oldest group having the highest (cc genotype frequency, 27%) frequency. there was however a similar cc genotype content in all three female (n=231) age groups (cc genotype frequency, 24 27%; p=0.795). correspondence: dr michael posthumus uct/mrc research unit for exercise science and sports medicine po box 115 newlands, 7725 tel: +27 21 650 4572 fax: +27 21 686 7530 e-mail: mposthumus@mweb.co.za michael posthumus (phd)1,3 alison v september (phd) 1,3 martin p schwellnus (mb bch, msc (med), md, facsm, ffims)1,3 malcolm collins (phd) 2,1,3 1 uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town 2 south african medical research council, cape town 3 the international olympic committee centre of excellence, newlands, cape town 38 sajsm vol 22 no. 2 2010 conclusion. the practical implication is that the selection of asymptomatic groups is of critical importance when future studies of this nature are designed. future research investigating this genetic variant as a risk factor for soft-tissue injuries should consider these findings when selecting asymptomatic participants. sajsm vol 22 no. 2 2010 39 the objective of this study was therefore to further examine the ageand sex-related changes in the col5a1 bstui rflp genotype frequency among the combined asymptomatic participants. more specifically, our primary aim was to determine if the cc genotype frequency of the col5a1 bstui rflp among male and female subjects without a previous history of tendon injury is age dependent. methods all 496 asymptomatic participants (265 male and 231 female) without a reported history of tendon injuries that were previously investigated in three separate publications were included in this analysis.3-5 because of the design of the previous tendinopathy studies, it was not possible to exclude those with a history of ligament injuries. prior to participation in these original studies, all participants gave written informed consent and completed a medical history questionnaire form. all descriptive data for the subjects with achilles tendinopathy, as well as the asymptomatic control groups, were previously reported.3-5 all three studies were approved by the research ethics committee of the faculty of health sciences of the university of cape town and/or the human ethics committee of la trobe university, melbourne, australia. the participants were combined and divided into three male and three female age groups: (i) ≤25 years old; (ii) 26 42 years old; and (iii) ≥43 years old. a chi-squared (χ2) test, fisher’s exact test or χ2 test for linear trends was used to analyse differences in genotype and any other categorical data between the groups. data were analysed using statistica version 8.0 (statsoft inc., tulsa, oklahoma, usa) and graphpad instat version 3 (graphpad software, san diego, california, usa) statistical programs. statistical significance was accepted when p<0.05. a one-way analysis of variance (anova) was used to determine any significant difference between the characteristics of the male and female age groups. hardy-weinberg equilibrium values were established using the program genepop web version 3.4 (http://genepop.curtin.edu.au/). results there was a significant linear trend (p=0.032) for the cc genotype frequency among the male age groups (fig. 1a). the youngest group had the lowest cc frequency (13%), and the oldest group the highest cc frequency (27%) (fig. 1a). the cc genotype content in all three female age groups (24 27%) was similar (p=0.795, fig. 1b). the general characteristics of the male and female age group tertiles are described in table i. table i. the general physiological characteristics of the male and female age group tertiles ≤25-year group 26 42-year group ≥43-year group p-value males n=83 n=112 n=70 age (yrs) 22.3±1.7*† 33.0±5.0*‡ 52.6±8.2†‡ (18 25) (26 42) (43 77) <0.001 height (cm) 180±6 180±6 178±7 (168 195) (167 201) (164 195) 0.590 weight (kg) 79.9±11.5 81.4±12.2 81.9±15.0 (61.7 110.0) (59.7 137.0) (58.0 136.0) 0.065 bmi (kg/m2) 24.5±2.8§ 25.2±3.4 26.0±4.3§ (18.5 31.7) (19.9 38.4) (20.2 39.3) 0.036 south african born (%) 79.5*† 47.7* 40.5† <0.001 australian born (%) 10.3 29.4 36.2 females n=63 n=108 n=60 age (yrs) 22.6±1.7*† 32.4±4.5*‡ 52.0±6.7†‡ (19 25) (26 42) (43 72) <0.001 height (cm) 166±7 168±7‡ 164±8‡ (152 179) (152 187) (145 181) 0.004 weight (kg) 61.2±6.5 64.4±9.0 81.9±15.0 (49.0 79.2) (48.0 87.0) (47.0 115.0) 0.051 bmi (kg/m2) 22.1±2.1† 22.9±3.0 24.1±4.6† (18.1 28.1) (18.1 33.2) (18.6 46.7) 0.005 south african born (%) 66.1*† 31.5* 21.7† <0.001 australian born (%) 25.4 48.2 56.7 values are expressed as mean ± standard deviation with the range in parentheses or as a frequency. the number (n) of male and female participants in each age group is also indicated. bmi – body mass index. post-hoc analysis: *<0.001; † <0.003; ‡ ≤0.002; § =0.026. discussion the main finding of this study was that there is a significant agedependent increase in the distribution of the col5a1 bstui rflp cc genotype in the pooled asymptomatic male participants of the three studies which investigated this polymorphism as a possible risk factor for musculoskeletal soft-tissue injuries. no similar trends were observed in the female subjects. we propose that the reported finding indicates that the youngest group of asymptomatic male participants consists of a mixture of individuals, similar to the general population, who are at low and high risk of musculoskeletal soft-tissue injuries (fig. 2). however, when older subjects (who would have had a greater amount of exposure to extrinsic factors) are analysed, individuals who may have been previously uninjured, would have developed an injury. therefore, when older asymptomatic participants are analysed, the group will contain a highly selected sample of the population at low risk of musculoskeletal soft-tissue injuries. this could explain the finding of a significant linear trend in the col5a1 bstui rflp cc genotype frequency and an increased chronological age in the male subjects analysed. this proposed explanation is further supported by a departure from hardy-weinberg equilibrium as observed in some of the groups presented in our previous studies.3 it remains unknown why a similar trend was not observed in females. it does however suggest that the col5a1 bstui rflp, as a risk factor for musculoskeletal soft-tissue injuries, is not age dependent in females. a limitation of this study was that it was not possible to analyse the south african and australian data separately owing to small sample sizes and uneven genotype distribution. a further limitation was that, although all participants were asymptomatic with regard to a previous history of tendon injuries,3-5 not all were free of ligament injuries (owing to the study designs). in conclusion, there was an age-dependent significant increase in distribution of the col5a1 bstui rflp cc genotype in the pooled asymptomatic male participants of the three studies which previously investigated this polymorphism as a possible risk factor for soft-tissue injuries. the practical implication of this finding is that the selection of control groups is of critical importance when future studies of this nature are designed. future research investigating this genetic variant as a risk factor for soft-tissue injuries should consider the findings of this study when selecting an asymptomatic control group. perspective genetic variants, such as the col5a1 bstui rflp, may have a significant impact on the prevention of musculoskeletal soft-tissue injures.6 genetic variants, together with other intrinsic and extrinsic risk factors, should eventually be used to identify individuals at increased risk of injury. once individuals are identified as ‘at risk’, carefully designed intervention programmes should be prescribed to 40 sajsm vol 22 no. 2 2010 fig. 2. proposed explanation for the significant linear trend in cc genotype frequency among the asymptomatic male subjects when divided into the three age groups (<25 years, 25 41 years, and >41 years). it is proposed that asymptomatic subjects in the age category <25 years will more than likely consist of individuals at high (black shaded) and low (no shade) risk of musculoskeletal soft-tissue injury. among older asymptomatic groups of participants (25 41 years, and >41 years) the relative proportion of individuals at high risk of injury will be reduced, as the likelihood of high-risk individuals becoming injured over time is greater than the likelihood of low-risk individuals becoming injured. fig. 1. the genotype frequency of the col5a1 bstui restriction fragment length polymorphism (rflp) in all (a) male and (b) female asymptomatic participants divided according to age into participants (≤25 years old black bars), 26 42 years old (thatched bars), and >42 years old (clear bars). a significant linear trend (p=0.032) for the cc genotype content among the male age groups was found. the number of subjects (n) within each category, as well as the hardy-weinberg equilibrium (hwe) p-values, are shown in parentheses. sajsm vol 22 no. 2 2010 41 prevent the injury from occurring and to assist the clinical management of these individuals. the current study provides further information on the col5a1 bstui rflp. the findings may help future studies investigating this genetic variant as a risk factor for musculo skeletal soft-tissue injuries and thereby assist future multifactorial risk models. acknowledgements this study was supported in part by funds from the national research foundation (nrf) of south africa (grant no. fa2005021700015 and fa2007032700010), the university of cape town, and the south african medical research council (mrc). avs was supported by the postdoctoral innovation award of the nrf. competing interests. none. references 1. clayton ra, court-brown cm. the epidemiology of musculoskeletal tendinous and ligamentous injuries. injury 2008;39(12):1338-1344. 2. meeuwisse wh. assesing causation in sport injury: a multifactorial model. clin j sport med 1994;4:166-1670. 3. september av, cook j, handley cj, van der merwe l, schwellnus mp, collins m. variants within the col5a1 gene are associated with achilles tendinopathy in two populations. br j sports med 2009;43(5):357-365. 4. mokone gg, schwellnus mp, noakes td, collins m. the col5a1 gene and achilles tendon pathology. scand j med sci sports 2006;16(1):1926. 5. posthumus m, september av, o’cuinneagain d, van der merwe w, schwellnus mp, collins m. the col5a1 gene is associated with increased risk of anterior cruciate ligament ruptures in female participants. am j sports med 2009;37(11):2234-2240. 6. collins m. genetic risk factors for soft tissue injuries 101: a practical summary to help clinicians understand the role of genetics and ‘personalised medicine’. br j sports med (in press) available on epub: http://www. ncbi.nlm.nih.gov/pubmed/19553227 guidance on prescribing alimentary tract and metabolism blood and blood-forming organs cardiovascular system dermatologicals genitourinary system and sex hormones systemic hormonal preparations general anti-infectives for systemic use antineoplastic and immunomodulating agents musculoskeletal system central nervous system antiparasitic products respiratory system sensory organs contrast media treatment of poisoning published by the south african medical association, the formulary is aimed at doctors, pharmacists, nurses, dentists and others concerned with the safe and cost-effective prescribing of medicines. the south african medicines formulary is researched and written by members of the division of clinical pharmacology of the university of cape town, in collaboration with health care professionals. the south african medical association, health and medical publishing group, private bag x1, pinelands 7430 isbn 978-1-875098-43-9978-1-875098-43-9 s outh a frican m edicines form ulary ninth edition 9 ninth edition produced by the division of clinical pharmacology, faculty of health sciences, university of cape town. published by the health and medical publishing group of the south african medical association. south african medicines formulary samf sam f the essential reference for ever y healthcare professional! the carefully and thoroughly updated 9th edition of the south african medicines formulary (samf) can now be ordered. it is your essential reference to rational, safe and cost-efficient use of medicines. that is why you should not prescribe without it. the newly published samf provides easy access to the latest, most scientifically accurate information – including full drug profiles, clinical notes and special prescriberʼs points. the convenient pocket-size design enables you to fit it comfortably into your bag or hospital coat pocket – always at hand for ready reference. w h y yo u s h o u l d n ’ t b e w i t h o u t t h e s a m f 9 t h e d i t i o n the new 9th edition of samf provides expanded information on key issues facing south african healthcare professionals today, including antiretrovirals, tb treatment guidelines, management guidelines for asthma and chronic heart failure, other common chronic conditions and prescribing in sport. • it presents practical, new approaches to the management of venomous bites and stings. • it outlines extensively the acute adverse reactions to drugs of abuse, and their management. • it features new as well as existing drugs, indexed by both trade and generic names. • it offers fresh insights into informed prescribing and carries cautionary guidelines on drug interactions and a range of special risk patients and conditions. and, as always, you can rely on... • the professional compilation and editing by a team from the division of clinical pharmacology, uct • an independent and unbiased guide on prescribing in south africa today • the indication of agents included in the sa and who essential drug lists • support of the sa national drug policy • guidance for prescribing during pregnancy and lactation, and in patients with porphyria, liver disease and renal impairment (including tables with drug dosage adjustments); and • indexed and page tabs for quick and easy access to each section. y o u r s a t i s f a c t i o n i s g u a r a n t e e d 3 e a s y o r d e r o p t i o n s : 1. phone edward or byron 021 6817000 2. fax the completed samf order form to 0866006218 3. email: edwardm@hmpg.co.za or byronm@hmpg.co.za guidance on prescribing alimentary tract and metabolism blood and blood-forming organs cardiovascular system dermatologicals genitourinary system and sex hormones systemic hormonal preparations general anti-infectives for systemic use antineoplastic and immunomodulating agentsmusculoskeletal system central nervous system antiparasitic products respiratory system sensory organs contrast media treatment of poisoning published by the south african medical association, the formulary is aimed at doctors, pharmacists, nurses, dentists and others concerned with the safe and cost-effective prescribing of medicines.the south african medicines formulary is researched and written by members of the division of clinical pharmacology of the university of cape town, in collaboration with health care professionals. the south african medical association, health and medical publishing group, private bag x1, pinelands 7430 isbn 978-1-875098-43-9 978-1-875098-43-9 s outh a frican m edicines form ulary ninth edition 9 ninth editionproduced by the division of clinical pharmacology, faculty of health sciences, university of cape town.published by the health and medical publishing groupof the south african medical association. south african medicines formulary samf sam f j o u r n a l o f t h e s a s p o r t s m e d i c i n e a s s o c i a t i o n spoils misdicini: v u l i n0 1 1986 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) osteoarthntic o f m ovem ent the osteoarthntic specific innovators in the field of antirheumatic medicine 1 diclophenac sodium 1 100 m g i , , ( l u l l /)!e s r r i b t n g m/tim w/j w n « » jjiraw 'a' r i m fe q e h t s e r lo f csba ct awv[ i »m>' ■ ' ' li .. . m, . kaft i tfi'l kt1 w relieves pain restores mobility k. oil one tablet p er day r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) contents journal of the s.a. sports medicine tydskr/f van dies a sportgeneeskundevereniging ciba-geigy 12-13 wm editorial comment sports medicine journal changes hands a interview ian holding on squash q running digest training-the practice part ii ej] letters r l book review feature guidelines fo rth e pregnant runner pregnant runners-take note! 53 psychology self-administered exertion therapy: its effectiveness and application — f^rt ii sascv nuusbrief waarom lid van diesasportgeneeskunde-vereniging sasma update why you should become a member of sasma gj] news from the regions f73 abstracts editor in chief dr c noble mb bch, fcs(sa) associate editors dr t noakes mb chb, md dr daw ie van velden mb chb (stell), m prax med(pretoria) advisory board medicine: dr i cohen mb chb d obst, rcoc orthopaedic traumatology: dr p firer bsc (eng) mb bch (wits) m med (orthoxwits) brig e hugo mb chb, mmed (chir) orthopaedics dr jc usdin mb bch, frcs (edin) cardiology: col dp myburgh sm mb chb, facc physical education: hannes botha d phil (phys ed) gynaecology: dr jack adno mb bch (wits) md (med) dip o&g (wits) front coven transparency courtesy of image bank. the journal o f the sa sports medicine association is exclusively sponsored by ciba geigy (pty) ltd. thejournal is produced by bates hickman and associates (pty) ltd., po box 783776, sandton 2146. the views expressed in this publication are those of the authors and not necessarily those of the sponsors or publishers. may 1986 v o l1 .n 0 1,1986 soortbe: kardiort tseringsen sport injury and ikxehabtirtasje cardiac rehabilitation program proaramme r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) reditorial commenti ~ he sa journal o f sports t m ed icin e has a new n am e-th e journal o f the sa sports medicine association. the reason for this is that we have a new sponsor-ciba-geigy (pty) ltd. in the present economic climate, spon­ sorship is extremely difficult to find and the journal must have the backing of sponsors. boehringer ingelheim (pty) ltd, our previous sponsor, decided to discontinue its support because of the downturn in the economy. on behalf of the editorial board and our readers i wish to thank the management of boehringer ingelheim for many years of support and the great kindness al­ ways shown to us. having said this, we would like to heart­ ily welcome our new sponsors, ciba ceigy (pty) ltd, with whom i am sure we will have a long and successful liaison. ciba-geigy is a pharmaceutical com­ pany which is already extremely well known in sporting circles the company has sponsored or helped to sponsor many previous sports medicine meet­ ings. o ver the years ciba-g eigy products have helped large numbers of injured sportsmen. the company has also provided the medical world with several excellent publications in many fields including sports medicine. these publications have usually been illustra­ ted by frank h netter, undoubtably the finest medical illustrator in the world. this expertise will now be utilised in the journal o f the sa sports medicine association. squash in this edition of the journal we have interviewed lan holding, a medical prac­ titioner who is also probably the best squash player in south africa. we wel­ come his valuable contribution. squash has many followers, including medical practitioners, but it is a game not without risk. northcoat assessed 50 players who died on the squash court or immediately after a gam e scientific assessment has been unable to show may 1986 vol 1, n 0 1,1931 sports medicine journal changes hands dr c noble mb bch, fcs (sa), editor-in-chief that squash was incriminated in their deaths it was not the squash that killed them but the state of their hearts squash, being a very stressful activity, may have played a contributory role, but even this has not been adequately proven. injuries certain injuries are specific to squash while others may also occur in other sports. the most important specific in­ jury is related to the e ye-d am age oc­ curring as a result of the player being struck by either the ball or the racquet. as squash is played in a confined space, a player is more likely to strike his op­ ponent particularly at the "hack squash" level where many of the play­ ers still use tennis strokes, in tennis a player has to watch one's op­ ponent in front of him, but in squash a player has to look back constantly to see where his opponent is going to play the ball. thus he is more liable to be hit by a squash ball on some part o f the body. a typical bruise is the most com­ mon injury-however, an eye strike may cause blindness protective equipment has been manufactured for this pur­ pose, but unfortunately most players do not encumber themselves with this form of facial protection. the non-specific injuries related to squash commonly seen in practice are ruptured achilles tendon, internal de­ rangement of the knee, backache and epicondylitis most of these injuries are seen in the older squash player (over 30 years), the younger squash player hav­ ing muscular tears and occasional torn ligaments of the ankle, hand or knee there are two reasons for injuries in older players. firstly, squash can be described as a load sport which means that pressure is exerted on certain 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) parts of the anatomy during the game the second factor is the ageing process. it has been clearly shown that after the age of 30 years the weakest parts of the musculo-skeletal system are the tendons specially close to the osseous attachment; not only this but the menisci tend to undergo degener­ ative change as well. the latter is fu r­ ther weakened by rotational loading which is part and parcel of the game of squash. heavy loading of the lumbar spine which is an integral part of the movements o f squash with rapid flex­ ion and extension may cause weaken­ ing of the discs with resultant disc prolapse or weakening of the pars inter articularis causing spondylolithesis which in itself provides additional load­ ing to the involved disc in rotator cuff syndromes such as bicipital and su paspinatis, tendinitis as well as tears are not uncommon in the older squash player as well in view of this, many peo­ ple feel that squash should be a young person's game. this in my opinion is un­ fair as many sports played by the older athlete may result in similar injuries. the possible cardiovascular improve­ ment which may come from heavy en­ durance activity such as squash is an excellent reason for the older athlete to play it is important, however, to ad­ vise all squash players who develop symptoms referable to cardiac insuffi­ ciency such as chest pain, shortness of breath and palpitations to stop playing immediately and undergo a medical ex­ amination as it has been shown that nearly all sudden death victims on the squash court had symptoms before a fatal game. early season rugby injuries the rugby season is with us again. un­ fortunately this will bring with it in­ numerable injuries, some of a severe nature, which will keep the medical professions busy once again. immedi­ ately sports physicians should think of the prevention of these injuries. unfor­ tunately many rugby players are not yet fit at the beginning of the season and therefore the chance of injury is greater. they should remember that in order to play rugby, one has to play the game properly. this involves off-season training and pre-season fitness peaking and then the practice of the game in the season. unfortunately the first two fa ce ts-o ff-se a so n and pre-season training-are forgotten by many of our rugby players. they arrive at the start of the season grossly unfit, very often having done little or nothing off­ season. this results in numerous liga­ ment and tendon pulls as well as an in­ ability by the player to take heavy knocks with resultant further damage. last year the fitness committee or­ ganised by the medical group of the iransvaal rugby football union held a fitness symposium that was poorly at­ tended by coaches. it is doubtful that it will be arranged again. it is unfor­ tunate that rugby coaches believe they know all about rugby and fitness re­ quirements and therefore do not have to be taught anything. "unfortunately many rugby players are not yet fit at the beginning of the season and therefore the chance of injury is greater. they should remember that in order to play rugby, one has to play the game properly. this involves off­ season training and pre-season peaking and then the practice of the game in the season." certain changes have taken place in the laws in order to reduce the incidence of injury in the g a m e -b u t this is not enough. one o f the major problems at all levels of rugby is the lack of strict­ ness applied to dirty play by the referee. foul play can be eliminated only by applying the rules very strictly and by enforcing adequate punish­ ment. about 10 years ago when i first start­ ed seeing large numbers of runners with injuries i could not understand why so many of them had to run despite their injuries. to try to under­ stand the runners further i took up long-distance funning. despite complet­ ing two comrades marathons and a number of standard marathons i was never "hooked" on running. i have had runners who have pleaded with me to run despite severe injury of such a nature that running was ex­ tremely painful. i have seen others who, having been forced to rest, have be­ come extremely depressed, some morose, some aggressive, but all show­ ing withdrawal symptoms similar to those in drug addiction. other runners, however, despite very high weekly dis­ tances appeared not to be too badly af­ fected by the running. a few even wel­ comed an injury that prevented them from running a major race. it would ap­ pear that the personality type to a large extent determines who gets "hooked" it is extremely difficult to say if this is a true addiction. over the last few years "endorphins", which are mor­ phia-like su b stan ce s, have been described by some americans as "the poppies of the mind" have been blamed for "addiction" in runners. although endorphins are increased by exercise, they have not been conclusive­ ly shown to be associated with addic­ tion. although the clinical features are very suggestive that running can be addictive, there is no conclusive evi­ dence of true biochemical addiction. i would suggest that all doctors read the chapter on runners' high in tim noakes' the lore o f running for an excellent discourse on this rather fascinating subject. running "addiction" r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) interview; ian on n 12 years of internation­ al-class squash, springbok ian holding (30) has been hit in the face less than 10 times. stitches were required on only three "i think the top players tend to hit the ball away from themselves into the corners," he says "generally, to prevent most squash injuries, a player must move out of the way to give the oppo­ nent freedom to play the ball. the rules don't permit wild play". dr holding, who holds bsc (biochemis­ try and genetics) and mb bch degrees from the university of the witwaters rand, has definite ideas about squash injuries. "squash can basically be regarded as a contact sport which is one aspect of squash injuries. secondly there are self inflicted injuries resulting from the na­ ture of the game, state of fitness and holding squash the environment in which it is played. the confined space, not watching the opponent and bad technique (which results in the racquet going into a much greater arc than it should) cause players to be hit. “this tends to occur around the head. injuries to the eyebrows and the face are generally common. the nose, teeth and lips could also be cut quite severe­ ly; he points out. "eye injuries can be serious and the ball and the racquet can cause major injuries" "after playing your body needs a good number of hours to recover. this is par­ ticularly true of stretched muscles technique and fitness will help to pre­ vent most musculo skeletal injuries. heat exhaustion can be a problem and should be avoided by not playing when it is very hot and humid and by drink­ ing plenty of water before and during play dr holding is admirably qualified to dis­ cuss training, injuries, diet, competition and all the other facets of squash. ten years ago he won his first sa amateur event and was the youngest winner in 30 years he has four national titles to his credit and several transvaal open titles. in 1976 ian reached the semi-finals of the world amateur championships in britain and in the same year he was the only amateur to be placed in the last 16 in the world championships he has scored several convincing wins over the world's leading players-the last being stuart dunport from new zealand who is ranked fifth internation­ ally. on his "good days" ian has beaten players ranked six, seven and eight in the world. however, he admits: "i have | always been limited by the fact that l have had a narrow peak at any stage of the season because of my univeristy studies. probably one of my assets is the ability to peak at a certain stage". in a wide-ranging interview dr holding spoke to the journal o f the sa sports medicine association. ouestion: do you actually time your peak-actually work it out carefully? holding: yes, i work it out pretty care­ fully, very much like bruce fordyce peaks for the comrades it is essential for me to peak for one or two events this explains why one can rise to great heights on some occasions and play averagely well at other times. ouestion: this is obviously something which you would expect. holding: any athlete would expect this because you cannot be 100% fit the whole time or at 100% peak per­ formance i think this is something the administrators and officials sometimes forget about. this causes quite a lot of conflict between the athletes and the officials. ouestion: where are you working at present? holding: i am a junior lecturer in prof tobias' department of anatomy at the wits medical school, it is a famous department with a great deal of histo­ ry. working there gives me a great op­ portunity to get to learn about the structure of the human body. may 1986 vol 1, n 0 1,193 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) practice partner is cary bental an en­ gineer and phd post-graduate student who is my coach and trainer. in short, he engineers my squash training. he is a good standard player himself and is a good analyst of squash playing. common training problems are over-' training and losing motivation. when one is tired you do not really get down to what you should be doing. it is very good to have a trainers input. i do a lot of mental training as well which in­ volves focusing on one event. mental focusing is very important in terms of actually achieving what you set out to do. in your skill training as well, if you develop the ability to mentally visualise the stroke that you are going to per­ form before you actually go and prac­ tise it, you will acquire that skill much faster than actually getting on to the court and practising for a longer time. in other words one can do five minutes of mental training with 15 minutes of practice and gain more benefit out of doing that than say an hour of prac­ tice i find that most of the top athletes tend to do this they set a goal and prosquash work through it and it becomes an ob­ tainable goal. mental training also en­ sures that one is more self confident. question; how much water should an in-training player drink? do you have definite ideas about diet? holding: it is essential to be adequate­ ly hydrated. fluids should be taken be­ fore and during the event and after the game, fluids should be replaced by plain water. it is also important to know that your carbohydrate storage is adequate and that you have adequate glycogen. this should be sufficient to last the whole game. your diet should be healthy and balanced. i tend to eat a vegetable based diet with hardly any red meat, which i replace with fish. you are basi­ cally what you eat. a mixture of le­ gumes and whole grains make this diet complete in proteins, and complex carbohydrates ouestion: what of the future? holding: generally i enjoy the game but i might not be too competitive over the next couple of years however, i think it is important to carry on exer­ cising every day to stay healthy and fit. question: lan could you describe your training programme for a major event? holding: ideally i try to plan my train­ ing around a yearly cycle, it is very much like the athletes would do. i do a good six months of background train­ ing which includes quite a lot of road running and court practising. at this stage the work is not very intensive. i concentrate on volume i would then also do some weight training. the ob­ jective is to develop stamina. once the season arrives i do about three months of transition training and then increase the intensity of my training. i try to de­ velop a bit more speed and adapt the background training that i have done to the specific demands of squash. con­ centrated playing and court training will help to sharpen my playing skills question: when you are doing road training, what sort of distances would you cover? holci . when i am playing squash as well, i tend to base my distances around five to eight kilometers, sometimes go­ ing up to sixteen, but i find that with an hour of squash it is more than ade­ quate. how l am feeling will determine whether i will run gently or attempt a time trial. there are times that i have clocked 17 minutes for a 5km time trial. i've recorded 28 minutes in an 8km trial. these are the preceding events that i would undertake they give one a mea­ sure of our fitness status there are also a number of court programmes which one can do. for ex­ ample, continuous running on the court simulating squash play. one can work for 30 minutes simulating squash without a ball but with the racquet-ac­ tually simulating the movements of play. this is quite important in the next three month period because fitness is basically specific to what you are doing. one should remember this. it is no good being really fit on the road when your muscles are not adapted to the squash movements. so a lot of time in the three month period is based on squash movements, stretching and the bending down as well as the very im­ portant twisting and turning move­ ments. at this stage i would also prob­ ably increase the weight training. general strengthening is so important that i work out three times a week at sam susa's gym in hillbrow. i use heavy weights for general strengthening and train for about 40 minutes each ses­ sion. i find that this is quite important as it tends to keep one's co-ordination together if you have the general body strength you tend to co-ordinate bet­ ter when you become tired in a hard game when l start competition training for the next three months, i hardly do any road-running. i try to develop my speed with the court sprints and then play and practise much more my court ma y 1986 vol 1, n 0 1,1986 5r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) training the practice part i timothy d noakes m b chb md metropolitan sport science centre, department of physiology, univer­ sity of cape town medical school and author of lore o f running (oxford university press) ntroduction fn the first part of this ar­ ticle on training, dr tim noakes discussed start­ ing out, shaping, rein­ forcement control, sti­ mulus control, goal set­ ting, associative/disassociative strate­ gies and coping thoughts. he also exa­ mined the question as to whether middle-aged people should undergo an exhaustive medical evaluation before they start practicing. in the second part of the series the author of the recently -published bestseller, lore o f running, gives invaluable advice about the selec­ tion of appropriate running shoes shoe advice for the novice, anatomy of the running shoe, shoe choice for uninjured runners and related topics choose appropriate running shoes once you have either cleared yourself, or your doc­ tor has given you the go ahead to start running, the next step is to choose an ap­ propriate pair of running shoes this is easier said than done. the choice of running< shoes has become enor­ mously complex. the 1985 shoe survey by the south african runner magazine listed 77 different running shoes for men and 10 for women; in the united states there are probably at least twice as many shoes from which to choose. unfortunately this problem is com­ pounded further by the fact that we are still unable to define those minor individual differences in body structure which determine which shoes are best for a particular individual (cavanagh, 1980). i feel that the choice o f the ap­ propriate running shoe is determined by two principal factors 1. whether or not you are a novice 2. if you are not a novice, whether or not you are injured. i) if you are injured, whether (a) you run enough to warrant expensive shoes and (b) for what you want to use the shoes ii) if you are injured, what type o f in­ jury you have. shoe advice for the novice it is always best to start running in a relatively modestly priced pair of shoes, bought from a reputable run­ ning shoe dealer. if after some months of running an injury occurs, the nature o f the injury will indicate what type of shoe is likely to help that injury and pre­ vent further similar injuries. but even if one is to enter that run­ ning shoe shop prepared to buy a modest running shoe, it helps to know something about the different fea­ tures of running shoes and how these features affect the performance of any particular model nike vortex anatomy of the running shoe there are six major anatomical features of any running sh o e -th e outer sole, the mid-sple, the presence or absence of other devices either in the shoe (arch or shank supports) or in the mid­ sole (variable density mid-soles) which help reduce pronation, the nature of the shoe-last, whether it be straight or curve-lasted, and the degree of medi­ al and lateral mid-sole heel flares the outer sole the outer sole is that part of the shoe that comes into direct contact with the ground. today, outer soles are made from a variety o f different materials and are of different designs. the main design variation is whether or not the sole has 'waffles'. bill bowerman filled a waffle toasting iron with urethane, producing the first outer sole with this characteristic p atte rn -h en ce the name. the most important feature of the outer sole is that it should not wear down too quickly, it should have the greatest durability in the areas of greatest wear, particularly at the out­ er heel edge this type of outer sole has been called the non-uniform outer sole the reason why very durable material is not used throughout the entire out­ er sole is that the more durable the material, the heavier it is thus the non uniform outer sole saves weight. the only benefit of a soft and therefore non-durable outer sole is that it pro­ vides additional cushioning which may be useful to those runners for whom e xce p tio n a l sh o ck a b so rp tio n is essential waffles were originally designed for cross-country, not road running as they give better trac­ tio n on uneven gro u n d (cavanagh, 1980). they also in­ crease shock absorp­ tion. however, waffles do not wear as well as flat surfaced outer soles. the shoe i most use, the nike vector, does indeed have a waffle outer sole and i have grown to prefer this as much of my running is done on mountain trails where the superior traction of the waffle is a bonus but i also have a foot strike that generates very even wear across the entire sole and thus the waffles last the life of the shoe. a final point is that i do not believe that the outer sole wear at the heel should necessarily be repaired unless it threatens to go right through to the mid-sole. the heels wear in order to ac commodate the natural heelstrike of the athlete. the athlete whose foot lands with the heel in marked supina the heel. to repatch such a heel cons­ tantly prevents proper adaptation of the shoe to the athlete's particular heel­ strike pattern. may 1986 vol 1, n 0 1,19^ r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) strike pattern. the important features o f the out­ er sole are durability and traction. the mid-sole the mid-sole is the real heart of the shoe and is the feature of the shoe that i always no tice first. the most important feature of the mid-sole is the y degree of softness / or hardness there are three different func­ tions of the mid-sole: it must be strong enough to resist excessive inward rotation of the ankle (pronation) as the foot progresses from heelstrike to toe-off; it m ust be able to flex at a point about two-thirds from the heel, as the heel starts to come off the ground leading to toe-off. prior to the mid-1970s, mid-sole material was made only from rubber which has dual disadvantages of being heavy and absorbing shock relatively poorly. in 1974, jerry turner of the brooks shoe company contracted a chemical engineer, david schwaber, to produce a lighter material with better shock-absorbing properties (cavanagh, 1980). the result was a compound called ethylene vinyl acetate (eva). tiny gas bubbles are trapped in the eva when it is cooled at high pressure; these bubbles make the material light and a good shock-absorber. the major disadvantages is that with wear, the tiny gas bubbles are expelled from the ev which flattens out, becomes hard­ er and absorbs shock less well. when the eva compacts down unevenly either in the heel or mid-sole, the shoe distorts badly and this may be an im­ portant cause of injury. another problem arises from the manufacturing process, it is difficult to produce eva o f consistent hardness as a result the quality of the mid-sole can vary from shoe to shoe. for these reasons, it is essential that the prospective shoe buyer check the mid-sole hardness of all the shoes he buys and learns to use the thum b com­ pression test to test the mid-sole hard­ ness that best suits him. in this test the mid-sole at both the heel and forefoot is squeezed between the fingers of both hands and the relaness mid-sole is estimat­ ed the greater the degree of mid-sole indentation produced by this method, he softer the shoe and therefore also the more shock that shoe can absorb, owever the added shock absorption hn.0lj)? ht at f pfic& the softer the shoe, the quicker it will tend to com­ pact down. conversely, the less indenmay1986 vol 1, n 0 1,1986 tation caused by the thumb c o m p re s s io n test the hard­ er the shoe, the less shock it will absorb, but also the less likely it is to compact down readily. i have already mentioned that the mid-sole m ust combine a capacity for shock absorption with that of control of ankle pronation and adequate flexi­ bility. yet to some extent, two of these characteristics are mutually exclusive; an eva which has good shock absorp­ tion will be soft and therefore have good flexibility but very poor pronation control, whereas eva which provides good control of pronation will be hard, inflexible and have poor shock absorb­ ing characteristics in an attempt to compensate for these mutually-exclusive characteristics, shoe manufacturers have used mid­ soles of different hardness in different a re a s-a soft, shock absorbing materi­ al along the outer heel border and un­ der the ball of the foot to increase shock absorption and flexibility; a firm ­ er material along the inner border of the shoe, extending from heel to mid foot, to control pronation. by and large, these techniques have been successful. the only problem that has not been effectively answered is the mid-sole underneath the ball of the foot. this area does not absorb the highest forces during la n d in g -th a t is done by the h e e l-b u t it is exposed to moderately high pressure for much longer time. thus it will tend to com­ pact down even more than the heel. yet it m ight be so ft enough to allow flexibility. one attem pt to solve this problem was provided by the nike tailwind, first released in 1979. in this shoe the mid­ sole contained a series' of five poly­ urethane tubes extending from heel to forefoot into which freon gas was in­ jected at a pressure o f about three at­ mospheres (cavanagh, 1980). while this shoe ultimately proved unsatisfactory because it had poor rearfoot control, its second, third and fourth generation offspring, the nike mariah, the nike odyssey and the nike v series have clearly shown that the air sole does not compact down as does conventional eva. however, in not one of these shoes does the air sole extend to the fore­ foot. if the air sole is present only in the heel, the eva under the forefoot will still be prone to compaction in those runners who, like myself, land heavily on the forefoot. in summary then, the features of the mid-sole that require consideration are its hardness and whether or not it is .made of mixed material. as we shall see, those who require shock absorption in their running shoes because they have f r i g i d ' lower limb structure m ust look & \ for shoes with soft mid-soles; ‘ those with 'mobile' feet need v firm er shoes -v \ the presence of slip or \ board-lasting during the construc­ tion o f running , shoes the nylon material that constitutes the shoe up p e r-th e part that covers the f o o t -is stitched together and its lower part is glued onto the top of the mid-sole. if this part of the upper is stuck directly to the mid­ sole and no additional material overlies it, then the shoe is said to be 'slip-lasted: alternatively, if a brown-coloured board overlies and hides the tucked-under portion of the upper, the shoe is said to be 'board-lasted'. board-lasting increases the ability of the shoe to resist pronation. the board may extend from heel to toe, in which case the board-lasting is said to be con­ ventional lasting. the benefit of partial board-lasting is that it does not reduce flexibility in the forefoot, yet retains some ability to resist ankle pronation. in general, board-lasted shoes will benefit those runners who require shoes to control their excessive ankle pronation, whereas slip-lasted shoes are best for those with rigid feet which, re­ quires as much movement as possible. 7r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) internal thermo-plastic heel counter which minimises excessive sub-talar jolntmovement external heel counter provides supportive base eva mldsole designed to counter excessive pronatlon inner sole which moulds to the runners foot and provides an extra shock-absorptlon layer. eel counter with or without heel stabilisers. the heel counter is made from a firm thermoplas­ tic m aterial th a t is moulded into the correct shape during a special heating process (cavanagh, 1980). some heel counters extend further on the inner than on the outer side of the shoe and, today, most are associated with special stabilising structures which tend to bind the heel counter more firmly to the mid-sole. the aim of the heel counter is to reduce ankle pronation. the athlete who requires a shoe that will limit his ankle pronation should obviously choose a shoe with a strong heel counter. there are two ways to test the strength of the heel counter. first, pinch the middle of the heel counter on its inner and outer edges between the thumb and the index in general it is held that a straight lasted shoe, because it contains con­ siderable additional mid-sole material under the midfoot, will help resist an­ kle pronation and should therefore be used by runners who require such con­ trol. in contrast, the curve-lasted shoe is of benefit to those athletes looking for increased foot movement and shock-absorption. such athletes usual­ ly have high-arched feet and tend to wear the outer edges o f their shoe soles and usually run with their toes pointing inwards (toeing-in). medial and lateral mid-sole heel flares the mid-sole of the shoe at the heel is usually wider on both sides where it meets the ground, than where it meets the foot; in other words, it is flared from foot to ground. the flare on the inside of the shoe probably resists ankle pronation; the flare on the outside probably increases ankle pronation because it acts as a additional arch supports systems are provided in some running shoes. by and large, these systems offer too lit­ tle to help runners who pronate exces­ sively but may assist those with only minor degrees of ankle pronation. the achilles 'protector is the exten­ sion of the material at the top of the heel counter. although some suggest that this ‘protector may be the cause o f inflammation in the achilles tendon, i have not encountered this. however, should the protector cause discomfort, simply remove it as it does not affect the function of the shoe in any way. the way in which a shoe is laced may affect its comfort. the two most com­ mon lacing methods are variable width lacing, in which there are two rows of non-aligned eyelet holes, which allows the athlete to choose either a narrow­ er or a wider lacing system and speed lacing in which plastic d rings are sub-, stituted for the conventional leather eyelets. the friction between the plas­ tic and pressure distribution is said to zx500 adidas fingers of your dominant hand. deter­ mine how much pressure is required to distort the heel counter towards the centre of the shoe second, holding the heel counter as before, grasp the mid­ sole of the shoe in the palm of the other hand and determine how much torque is required to distort the heel counter to the inside or to the outside of the shoe the less distortion produced by these manoeuvres, the stronger the heel counter. straight or curved (banana) lasting. a straight-lasted shoe is one which, when viewed from below, is symmetri­ cal around a line drawn from the mid­ dle of the heel to the middle of the toe in contrast, the front of a curved banana or inflared-lasted shoe bends in­ side a line drawn from the middle of the heel to the middle of the mid-foot. lever forcing the foot inwards at heelstrike thus it seems likely that the medial heel flare may be of value to runners who need control of ankle pronation, but the lateral flare is probably more of a hindrance than a help. indeed when in the mid-1970's nike introduced a shoe with an exaggerated lateral flare, the l d v 1000, a number of runners us­ ing the shoe developed the iliotibial band fric t io n syn d ro m e (cava­ nagh, 1980). it seems probable that lateral heel flares will disappear sometime in the fu tu re certainly the injured runner who uses a shoe with a lateral heel flare would probably do best to file that flare off. there are a number of other less im­ portant features worthy of note all modern shoe uppers are made of ny­ lon. leather tends to stretch once wet and it needs to be dried slowly. be more even with the d rings. however, plastic d rings are hard and can cause considerable pressure on the top of the foot. a recent innovation in lacing has been the use o f velcro strips in place of laces finally, some shoes also have sup­ plementary lacing systems in which tabs at either the midfoot or the heel allow the laces the be attached to either the mid or rearfoot, or both. final considerations having decided what model shoe one is going to buy, it is important to make sure the shoe fits here four rules apply. first, a general rule is that the shoe should be bought slightly larger than the runners conventional shoes this is because the foot swells about one half size when he runs. a good test of whether the shoe is of the correct size is that the width of the index finger may 1986 vol 1, n01,198< r r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) "all running shoes have a limited life expectancy-a probable maximum o f six months of dally wear-before their ability toabsorb shockor control the foot is lo st so it is advisable to change shoes about that often. " a question runners frequently ask is whether they should train in a shoe that is heavier than the ones in which they normally race i don't really think that the weight of the training shoe makes any real difference to the over­ all training effect. distance and speed are what count in training and shoes should be chosen so that they are com­ fortable and protective shoes for cross­ country racing can sacrifice some cushioning and should have a low heel to increase stability on uneven ground. shoes for ultra-marathon races need more cushioning as do shoes used if one is training high mileages. joggers who train less than three times a week, or who run less than 20 kilometres a week probably do not need the addi­ tional protection built into the very ex­ pensive running shoes, although they may should they become injured. as far as different brands or models of shoe are concerned if you are com­ fortable in a particular brand of shoe, you should stay with that shoe. i have found that i am comfortable in only a small range of shoes. yet any number of other shoes which seem to have the identical characteristics as these shoes are, for no apparent reason, simply not comfortable (continuedonpagelo)c ibo-g eigy (pty) l td p.o. box 9 2 isando 1 6 0 0 for full prescribing inform ation please re fe r to the m.d.r. may 1986 vol 1,n 0 1,1986 tenderness in any o f these areas in­ dicates, amongst other things, that the foot is being allowed to pronate exces­ sively and that a shoe with those fea­ tures that restrict ankle pronation should be worn. it is important not to race in shoes that are either too light or too worn out. the muscles normally provide a good measure of overall shock absorp­ tion during running, but near the end of a long race, they become too ex­ hausted to help, so that the shoe is left to absorb the shock unaided. a shoe that felt adequate at the start of the race may not be optimum when it must cope without the help of the muscles all running shoes have a limited life exp ectan cy-a probable maximum of six months of daily w ear-b efore their ability to absorb shock or control the foot is lost. so it is advisable to change shoes about that often. votiarenqpin sports injury and trauma. diclophenac sodium 50 mg (entericcoated tablets) reg. ho. k/3. i / 2 5 3 (wet/act 101/1965) 153 should be able to fit between the end of the longest toe (not always the big toe!) and the front end of the shoe upper. second, the width of the shoe must be right and there must be sufficient height in the toe-box to allow free up and-down movement of the toes. ath­ letes with very wide or very narrow feet will need to look to manufacturers who offer shoes with different width fittings or will need to discover those manufacturers whose normal width range tends to be either broader or narrower than the average running shoe the most important width fitting is over the middle (bridge) of the foot. third, the shoe m ust feel good im­ mediately you walk in it. a shoe that feels uncomfortable in the shop will only become even more so once on the road fourth, the heel must not slip out of the heel counter at toe-off. shoe choice for uninjured runners once the novice has been running for some time and has not experienced an injury, he becomes an uninjured non-novice runner and the choice of his second pair of shoes requires sever­ al new considerations. if the novice suffers an injury that may be related to his choice of running shoe, then he becomes an injured runner and his choice of shoe is determined by a different set of factors. uninjured runners fall into two categories-those who are at risk of in­ jury but who are not yet running enough to become injured, and those fortunate few who can do whatever they like without ever becoming in­ jured. this latter group comes from ex­ perienced ru n n ers-th e ir choice of shoes can be made entirely without recourse to any of the information con­ tained here they could probably run barefoot if they trained for it. one way for the uninjured novice to check whether he may be injury prone, is to try the pinch test. the pinch test is effective because damaged tissues become tender to the touch long be­ fore they actually cause pain to be felt during or after running. a feeling of tenderness or discomfort when either v the argus the achilles tendon is pinched between the thumb and forefinger, or when firm pressure is applied along the bord­ ers of the shin-bone (the tibia) or the knee-cap indicates trouble if allowed to go unchecked, the result may be a de­ bilitating injury. 9r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a rthritis/running link i refer to your article on the topic of the possibili­ ty o f a linkage between running and arthritis on page 5 of your issue no 29. you referred to a research study done by caldwell and reported in the physician and sports medicine of august 1984, in which a questionnaire study of swim­ mers and cross-country runners was carried o u t the statistics derived from that study showed no linkage between road-running and arthritis o f any kind. in this connection i would like to sound a note of caution when it comes to the elderly runner. cartilage cells, like brain cells, die o ff progressively from skele­ tal maturity onwards. this does not mean that articular cartilage automat­ ically gets thinner in advancing years, but its capacity to regenerate itself reduces progressively, and becomes minimal in old age. translating this in­ formation into practicalities, it follows that a young athlete easily regenerates cartilage as superficial attrition occurs; but in old age this ability is lost. a properly controlled scientific study is called for in order to determine whether or not athletically active older people are subject to a higher inci­ dence of osteo-arthritis than the more common sedentary members of that community. until such a trial is con­ ducted, we should discourage people over the age o f 50 years from long­ distance cross-country running. i have had several patients with what appears to me to be unnecessary arthritis produced by overuse in old age; and this observation has been corroborated by colleagues abroad. prof aw b heywood, department of orthopaedic surgery, universi­ ty of cape town.editor-in-chief dr clive noble re­ plies: there is no published evidence to show that running over the age of 50 in­ creases the rate of degeneration of normal joints. there is in fact evidence to the contrary. in a study o f former champion finnish athletes1 it was found that advanced degenerative osteo-arthritic changes were found in 4% of the group but were present in 9% of the control group. other studies2 indicate that the inci­ dence of osteo-arthritis is no higher in highly active sport persons than in the non-active population. wally hayward who is approaching 79 years of age had no evidence of osteo-arthritis despite years of running prodigious distances furthermore there is evidence3 to support the belief that the absence rather then presence of normal weight bearing across a joint leads to degener­ ative changes similar to those found in early osteo-arthritis. to conclude, it has been established that a history of joint injury pre-empts osteo-arthritis, thus exercise on abnor­ mal joints could ultimately cause de­ generative osteo-arthritis it would pos­ sibly be wise to discourage any patient (regardless of age) with known joint damage, from excessive activities thus it is my opinion that there is no need to discourage persons over the age of 50, with normal joints, from long dis­ tance running. references 1. puranen and colleagues (1975). 2. adams 1976, bird eta/, 1980, edm ond eta/, 1980, murray leslie eta/, 1977. 3. palmoski et al (1980). 4. murray leslie et al, (1977). s p o rts q u iz 1. who beat bjorn borg in a wimbledon final? 2. who wrote the screenplay for chari­ ots o f fire? 3. what was president eisenhower's favourite game? 4. who was the first person to hit six sixes in an over of first-class cricket? 5. complete the couplet "float like a butterfly, sting like a bee 6. what us president was a keen jo g­ ger? 7. which golfer recovered from a ta d car crash to win the us open? 8. who was a wimbledon finalist at the age of 19 and again at 39? 9. who won the 5 000 and 10 000 metres and marathon in the same olympics? 10. what is the usas premier sports magazine? from utterly triviai knowledge: the sports game by david robins (penguin books, 1985). paiejjsniii s u o d s oi >)0deiez i!lug '6 liemssoa ua» -8 u e b o h u a a l j d j j e j a iu l u ir ’9 ass },ueo aad s/m ib l im 3!m l u e o s p u e i) s ih '5 s j 0q o s p i a y j e o '17 j i o o •£ p u e p m u||o0 z 0ojugoi/\i u q o r t sj0msuv (continued from page 9) in summary then, my advice for the uninjured runner is to stay with the shoes that he finds comfortable and to choose shoes that are appropriate for racing and training and for different distances* *republished with the permission of dr tim noakes, author of lore o f running (oxford university press). references basslertj. marathons and im m unity to athe­ rosclerosis. annai o f the n ew york academ y of sciences 1977; 301: 578-592. cavanagh p. the r unning shoe book. ander­ son world, moutainview, california 1980. lobstein dd. depression as a pow erful dis­ crim ination between physically active and sedentary m iddle age men. jo u rn a l o f psy­ cho so m a tic research 1983; 27; 6 9 -7 6 . martin je. behavioural m anagem ent strate­ g y fo r im proving health and fitness. journal o f cardiac rehabilitation. 1984; 27: 6 9 -7 6 . noakes t. marathon running and im m unity to coronary heart disease; fact vs fiction. clinics in sp o rts medicine; 3; 527-543. may 1986 vol 1, n 0 1,19® r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports medicine continuing education course-provisional programme presented by the sa sports medicine association. venue: bozzoli hall, university of the w itwatersrand 8 9 august 1986 friday 8 august 08.00-08.40 registration 08.40-08.50 welcome: sasma president 08.50-09.10 diet and the sportsman 09.10-09.30 drugs and sport 09.30-09.50 strength and fitness for sport energy utilisation and fluid balance in marathon running 10.10-10.30 heat injury and sport 10.30-10.50 cardiac prehabilitation 10.50-11.00 discussion 1 1 .0 0 -1 1 .1 0 t ea 11.10 -11.3 0 cardiac rehabilitation 11-30-11.50 heart disease and the sportsman 11.50-12.10 psychiatry and sport 1 2 .1 0 1 2 . 2 0 discussion 12.20-12.40 film.-heart 12.40-13.00 lunch 13.00-13.20 footbiomechanics 13.20 -13.40 ankle injuries (soft tissue) shin splints and other shin pain 14.00-14.20 meniscal injuries 14.20-14.40 anterior cruciate instability 14.40-15.00 patello femoral injuries 15.00-15.10 discussion 15.10-15.30 film.-injury 15.30-15.40 tea a.g.m. sasma dinner: friday evening saturday 9 august 1986 no'22£9,20 lumbar disc pathology 09.20-09.40 shoulder injuries 09.40-10.00 elbow injuries /in —10.20 hand and wrist injuries 10.20-10.40 discussion 10.40-10.50 ifca ^ 0 1 1 1 0 sports injuries in the child i t 'in v i'ln sport and the pre9nant woman physiotherapy of running injuries i ' m n rehabilitation of knee injuries 1 £ '" }r rehabilitation of muscle injuries 12.30-12.40 discussion speakers: speakers invited to present papers include dr c noble, dr t noakes, dr p firer, brig e hugo, dr r morris and dr n gordon. registration: registration: r120 per person for the course send personal details and registration fees to: mrs a schuster r0. box 55539 northlands 2116. supported by ciba-geigy (pty) ltd bm lith o 30 970 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) lore ©f running by dr tim noakes, oxford university press seldom have i had the opportunity of reading a more enjoyable and stimula­ ting book on sports medicine not only is dr tim noakes' book packed with in­ teresting and useful information on running but it is written in a style that makes for pleasant reading. written at a medical level it had nonetheless been ardently read by many of the runners themselves, espe­ cially the "addicted ones". for me the section on running injuries was partic­ ularly interesting. some of the treat­ ments suggested -su c h as a change of running sh oe sare particularly innova­ tive for the stereotyped orthopaedic surgeon or sports traumatologist. it is a pity that new running shoes used in the treatm ent of running injuries can­ not be paid for by medical aid! i believe that every doctor, physiotherapist or podiatrist who treats running injuries should make himself familiar with this book. it is sometimes controversial and always thought provoking. dr clive noble m b bch, fcs (sa), editor-in-chief sports injuries, their prevention and treatment by lars peterson and per renstrom. juta and company ltd. 1986. the authors of this book, lars peter­ son and per renstrom, are two leading swedish orthopaedic surgeons, both ex­ pert and widely experienced in treat­ ing sports injuries. sweden has led the world for many years in sports science, and the origi­ nal swedish edition of the book has been so successful that it is now being made available to the english-speaking world. this edition has been revised and updated, not only by the authors, but by an international team of english speaking editors. editors of the south african edition are duncan mitchell, professor of phy­ siology, university of the witwatersrand and george beaton, formerly professor of medical education at the same university. sports injuries is a handbook for physical educationists, coaches, trainers, physiotherapists, first-aiders, fieldside care specialists, serious sportsmen and sportswomen and anybody else con­ cerned with preventing and treating in­ jury in sports. using plain language and clear dia­ grams, the authors systematically cover the parts of the musculoskeletal sys­ tem susceptible to injury in sport, show­ ing how the injuries happen, how to prevent them, and especially how to get an injured participant back into his or her sport safely and quickly. with an increasing number of peo­ ple taking part in both amateur and professional sport, there is now a great­ er demand for clear understanding of all types of injury; early and correct di­ agnosis; fast, efficient and effective treatm ent and a knowledge of preven­ tive and rehabilitative training. the 488 page sports injuries hand­ book gives clear, practical instruction and advice on: • sports injuries by region including the back, neck, head, spine, arm, knee, lower leg, ankle, foot and trunk • warm-up, stretching and taping • good protective clothing and equip­ ment • preventive and recovery training in a colour-illustrated 45-page section •special child and adolescent activities • sport for the handicapped. with over 240 colour photographs and x-rays, over 130 specially commis­ sioned full-colour diagrams and an ex­ tensive glossary, this comprehensive book will be indispensible to all those involved in sport and should be part of every kit bag. sports medicine in primary care by robert c cantu, collier macmillan international this compact volume is designed espe­ cially for general office practice. it ena­ bles physicians to write exercise prescriptions, dispense knowledgeable information on sports nutrition, coun­ sel patients on health, life-style and prevention of injury, treat common in­ juries in each organ system and identi­ fy indications for referring patients to an appropriate specialist. describing the 240 page reference book the journal o f family practice comments "... a well-written and illus­ trated book for all those in family prac­ tice who are interested in sports medi­ cine. it may be used as a textbook for medical students and resident physi­ cians or as a reference book for prac­ tising physicians:' the opinion of physical therapy m s-."... highly recommended for sports physi­ cal therapists because it provides a ver­ sion of the field o f sports medicine." sp o rts m edicine, sp o rts science: bridging the gap. edited by robert c cantu ana william j gillespie, collier mac­ millan international. the editors offer broad coverage of the medical, physiological and psycho­ logical assessments needed before ex­ ercise training. it deals with specific ex­ ercise programmes and with special considerations such as nutrition, dia­ betes, cardiac rehabilitation and the prevention, recognition and treatment o f sports injuries common among adults. commented the new england jour­ nal o f medicine-."... a good book for the hospital medical library. it will be used by numerous specialists and physical therapists, also by trainers.." contents include: psychology and sports-attitudes and beliefs in the prediction o f exercise participation, change agents in the psychology of running and behaviour modification. there are also chapters on biomechan­ ics, perspectives on the female athlete, sports nutrition and cardiac rehabilita­ tion. ma y 1986 vol 1, n 0 1,1986 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) rfeaturei guidelines for the pregnant runner he decision by mary decker-slaney to co n ­ tinue running right up to the end of her pregnan­ cy has focused attention on the pregnant runner ambitious "queen mary" will let nothing prevent her from returning to world middle-distance com petition-not even the birth of her first child. unlike some top class women athletes who gave up running during pregnan­ cy mary continues to put in 6 0 8 0 km per week with her doctor's consent. the 27-year-old mother-to-be told jour­ nalists: "the doctor says it is ok to do what i am used to but i get slower and slower and bigger and bigger. in his book lore o f running (oxford university press) the author dr tim noakes discusses both the potential hazards and benefits of exercise dur­ ing pregnancy. four potential areas o f concern must be considered: • exercise compromises the blood flow to the developing foetus • blood ph and lactate changes in­ duced by high intensity exercise may affect the foetus. • maternal hyperthermia during exer­ cise may affect the foetus. • maternal exercise increases the risk of premature labour benefits of exercise what scientific evidence there is indi­ cates that exercise training during pregnancy increases physical fitness without detrimental effects, in the short term the mother feels bet­ ter and has more energy and suffers less of the common complaints that are associated with pregnancy, in par­ ticular, constipation, back pain and reduced energy her weight gain is bet­ ter controlled. during labour the fit mother is better able to cope with whatever happens during delivery, in particular the possi­ bility of complications. strong abdomi­ nal muscles aid the expulsion of the baby, and well-toned pelvic floor mus­ cles stretch better during delivery and recover more quickly comments dr noakes: "however, these differences may be more psychological than physical. for in the only five such studies yet reported, co ntrasting results of the effects on training dur­ ing pregnancy on the outcome of labour was found. in three studies the labour and delivery of women who had exercised during pregnancy were no different from those who had not if anything, the exercising women were slightly more likely to develop delayed (obstructed) labour requiring caesarean section than were the non-exercisers. but the numbers were small and no definite conclusions can be drawn. in contrast a hungarian study of 172 athletes6 6 % of whom continued their sporting competition during the first three to four months of pregnan­ cy-show ed that these athletes had fewer complications than normal dur­ ing pregnancy and there was no in­ creased risk o f abortion. labour and delivery were normal, except the rate o f caesarian sections were half that of the control group as was the duration of the second stage of labour in the long-term the mother who has been active during pregnancy will find it easier to lose weight and to recover from the effects of the delivery and pregnancy image bank may 1986 v o l1 .n 0 1,19 12 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) he american college of obstetricians and gynae­ cologists gives pregnant runners the following useful information: • before continuing with your running you should consult a doctor. certain medical conditions preclude running during pregnancy. these may include placenta previa, multiple pregnancies, a history of miscarriages, a weak cervix, hypertension, anaemia, diabetes, or thyroid disease. • don't try to start a more rigorous training programme. you should be prepared to cut back on intensity and distance. don't push yo u rself to exhaustion. • exercise at least three times a week for 20 to 30 minutes for maximum benefit. your heart rate should be in the 120 to 140 range. after you stop running your resting pulse should be back to normal within 10 minutes also remember that your resting pulse will rise during pregnancy. • you should drink plenty of fluids and avoid overheating. an increase in body temperature can harm the foetus, which has no mechanism to cool itself. dehydration can interfere with blood circulation and may trigger premature labour. •avoid aggressive competition and be­ come a fun-runner instead. if you feel that you are straining or becoming ex­ cessively fatigued you should stop run­ ning. you should also discontinue train­ ing if you experience breathlessness, dizziness, headaches, muscle weakness, nausea, chest pain or tightness, back pain or pubic pain. in these circum­ stances you should consult a doctor. •slow, gradual stretching should be in­ cluded as part o f your warmup and cool down. kegal's exercises for the pel­ vic muscles are also recommended, both prenatally and postpartem. • don't try to lose weight by exercising during pregnancy. you should concen­ trate on a balanced diet to meet your caloric needs as well as the needs of your baby and your exercise. •strenuous exercise, if done at all should not exceed 15 minutes in dura­ tion. • do not run if you have a fever. •do not run in hot, humid weather. this information is based on a recent ouiietin of the american college of ob­ stetricians and gynaecologists, 600 m a r v ^ d ave, sw washington, dc f0024 and research from the melpo­ mene institute, 316 university ave, st paul, ml\l 55103. may 1986 vol 1, n 0 1,1986 pregnant runners take note image bank r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) self-administered exertion therapy: its effectiveness & application-part ii van niekerk, m b a (hons) psychology schomer, h h ba (hons) ma phd psychology department o f psychology, university o f cape town, rondebosch, 7700. s ummaryhe authors have exa­mined the effectiveness of anxiety management training through physical exertion (running) and positive and negative imagery without an ongoing client therapist relationship. their study sug­ gests that self-administered exertion therapy, with its simple, cost-effective and readily amendable techniques is a valid and viable alternative means of al­ leviating certain forms of anxiety. it is hoped that their study will stimulate further research. results the results obtained from the present experiment clearly indicate that a combination of physical exertion and positive and negative level without the presence of a facilitator. ex­ perimenter effect was thus shown not to play any significant part in anxiety reduction. the data obtained from the experi­ ment was analysed by means of a 2-way analysis of variance (2-way anova) with repeated measures on factor b table 1 summarises the analysis of variance of the i pat langner index and poms re­ spectively. significant f-interaction occurred at the 0,01 level i.e. anxiety scores did not change consistently over the four lev­ els of instruction as time proceeded. simple main effects analyses of all three psychometric devices employed indicated that: (a) during the second and third week of the programme there were significant differences be­ tween the anxiety scores of the four groups (b) one week after termination of the programme the anxiety scores o f the four groups still differed signifi­ cantly. (c) within each group, with the exception of croup 4 (the control group), anxiety scores fluctuated sig­ nificantly over the five weeks tukeys hs pairwise comparisons re­ vealed th a t during the middle of the second week of the programme the anxiety scores of the group receiving a manual only was significantly less than those in the control group. it was table i 2-way anova with repeated measures on factorb(tim e intervals) d v : anxiety level ipatdata anova sum mary table source ss df ms f -ra tio between subj. subj.w c 4178.729 2616.793 2 32 1392.9097 113.02478 12.323932 within subj. b ab bxsw c 3954.9902 2339.3188 1798.1016 4 12 128 988.74756 194.94324 14.047668 70.385171 13.87724*' langner index data between subj. a subj.w c 6103.9248 3527.8594 3 32 2034.6416 110.24561 18.455535 within subj. b ab bxsw c 4996.7886 3934.7622 2893.2578 4 12 128 1249.1971 327.89685 22.603577 55.265463 14.506414" poms data between subj. a subj. wg 2059.7338 4199.866 3 32 686.57794 131.24581 5.2312369 within subj. b ab bxsw c 1084.8675 1008.8215 2537.9124 4 12 128 271.21687 84.068459 19.82744 13.678865 4.2400056” ** p < 0,01 with factor a =m etho d of instruction a =0,01 0* f (12;128> may 1986 vol 1, n 0 1,19® r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) only during the third week of the programme that the other experimen­ tal groups (i.e. the group receiving a manual and an audio-tape, and the group receiving a manual and an audio­ tape and a video-tape) exhibited signifi­ cantly less anxiety than the control group. on te rm in a tio n o f th e programme these trends were still evi­ den t i.e. the anxiety levels o f those in the experimental groups were still sig­ nificantly less than those in the control group graphical representations of the anxiety reduction patterns can be seen in figures 1 to 3. in addition the above are expressed in relative percentage fluctuations in figure 4. 54 52 50 48 46 u} 4 4 (d > 42 4 3 £ 40 •s 38 ^ § 36 34 32 30 28 weekly trials r ®i b2 03 ba e5 group 1 (manual only) group 2 (manual plus audiotape) group3 (manual, audiotape plus video) group 4 (control) figure 1: graphical representation oftheipatdata discussion the results suggest that anxiety reduction through physical exertion and positive and negative imagery can occur in the absence of an instructor. contrary to expectation, the study shows that neither the maximal treat­ ment group (i.e. the group receiving a manual, an audio-tape and a video­ tape), nor the group receiving a manu­ al and an audio-tape as instruction ex­ hibited significantly more anxiety reduction than the minimal treatment group (i.e. the group receiving only a manual). results revealed that neither rate nor amount of anxiety reduction |s positively correlated to complexity of instructional level. the results suggest that the manual alone was superior to combinations o f the manual, audio­ tape and video-tape in reducing state anxiety. although it was hypothesised that r l e maximal treatm ent procedure would yield significantly more anxiety eduction than the other treatm ent aroups, results indicated that this did not occur. video-tape pre-training did not significantly facilitate therapeutic outcome. these unexpected results could be attributed to a variety o f fac­ tors contrary to the findings of hilkey and wilheim (1982), the results of the present study may be seen as a result of removing possible therapist rein­ forcement from the video-tape pre­ t ra in in g sessions. sin ce th e ex­ perimenters were always present at these sessions in the hilkey and wilheim study, ascertaining the exclu­ sive effect of video-tape pre-training on therapeutic outcome is difficult. as­ suming that it is the video-tape pre­ training alone which enhances treat­ ment effects is fallacious. postulating that learning the rules and principles that govern a particular behaviour is more conducive to be­ havioural or cognitive change then sim­ ply copying the behaviour, is an alter­ nate aetiological speculation to the cur­ rent findings the former method of learning forces one to restructure one's cognitions about anxiety. the latter method of learning, as happened in the maximal treatment group, can be seen as an imposition of ideas. this is not only counter-productive to adequate personal problem-formation (roman ovska, 1982), but also to the integration of the learned behaviour in the per­ son's repertoire of covert and overt responses although it was hypothesised that the minimal treatm ent group would yield significantly less anxiety reduction than the maximal treatm ent group, the results refuted the hypothesis: rate and amount o f anxiety reduction was greatest in the group receiving only a manual. the role of self-attribution may be central to these findings, for they support indications from differ­ ent areas of self-attribution research that therapeutic outcome is influenced by the client's belief about the causes of behavioural changes those subjects ma y 1986 vol 1, n 0 1,1986 b, b2 b3 b< b5 ------group 1 (manual only) ----! group 2 (manual plus audiotape) ------group 3 (manual, audiotape plus ( video) r : : . group 4 (control)_____________ figure 2: graphical representation o f langner index data — group 1 (manualonly) — group 2 (manual plus audiotape) — •! group 3 (manual, audiotape plus video) ... i group 4 (control)____________ figure 3: graphical representation of the p o m s data in the group receiving only a manual as instruction believed that they had the sole responsibility for some action, that a successful outcome would be due to their personal competence and that their behaviour was not only voluntary but also internally mediated. as opposed to this, the subjects in the maximal and intermediate treatm ent groups could have perceived the audio­ tape as an external pressure. this led to a consciously or unconsciously medi­ ated opposition to treatment. the co­ operation necessary to achieve max­ imal treatm ent effects turns into ac­ tive opposition, i.e. reactance occurs (kanfer & goldstein, 1980). a further aetiological speculation for the superior efficacy of the manual is similar to that posed by condry (in: kanfer & goldstein, 1980). the manual alone could have demanded the de­ velopment o f greater self-knowledge and self-exploration (to achieve treat­ ment effects) than the audioand video-tape. this in turn could have led to the establishment of a durable in­ ternalised repertoire of the desired responses condry argues that skills ac­ quired in this manner are better in­ tegrated into the individual's schema and hence more m ean in gfu l to him/her. this in turn leads to superior internalisation of complete repertoire of behaviours conducive to positive change. in the context of the research on forced compliance (which might tenta­ tively be postulated as one of the dy­ namics underlying the findings in groups 2 and 3), collins et. al., (in: kanfer & goldstein, 1980), called atten­ tion to the importance of the recogni­ tion of variables which are associated with the acquisition of skills under per­ ceived external manipulation may ac­ tually be antagonistic to the main­ tenance or internalisation o f such skills (continued ori page 18) 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) in sports injury and trauma. votta didophen for fu ll p r e s c r lb i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) waarom lid word van die sa sportgeneeskunde vereniging? [ ie sascv staan nog in sy kinderskoene, maar groei r steeds in lidmaatskap. aangesien heelwat po t tensiele lede van die sasgv iets meer wil weet van die doelstellings van die vereniging, asook die persoonlike voordele wat hulle kan ver kry uit lidmaatskap van die vereniging, wil ons graag die doelstellings van die vereniging uiteensit. deur aan te sluit by die sasgv, word u deel van 'n groep kollegas met gemeen skaplike doelwitte, nie net plaaslik nie, maar ook in die streke en op nasionale en internasionale vlak. dit is 'n akademiese forum waar idees, sienings en ondervindinge gewissel kan word op 'n gereelde basis-'n netwerk van kolle­ gas dwarsdeur die land met wie u per soonlik in aanraking kan kom indien no­ dig. wat is die sa sportgenees kunde-vereninging? die sa sportgeneeskunde-vereniging (sasgv) is 'n professionele vereniging wat betrokke is by alle aspekte rakende die sportgeneeskunde. aangesien die sasgv 'n subgroep is van die mediese vereniging van sa (mvsa), bestaan die lede uit geregistreerde mediese prak tisyns wat lid is van die mvsa uit beide die private en openbare sektore. aangesien daar soveel belangstellendes in sportgeneeskunde is wat nie lede van die mvsa is nie (beide medici en nie medici) is daar voorsiening gemaak vir nierdie persone om geaffilieerde lede van die sasgv te word deur aan te sluit by diesportwetenskapafdeling van die suid-afrikaanse vereniging vir sport wetenskap, liggaamlike opvoedkunde en rekreasie (savslor). geneeshere wat nie lede is van die mvsa nie, fisiotera peute, liggaamlike opvoedkundiges ens moet voile lede van savslor word. so aoende sal hulle name op die poslys 9eplaas word waardeur hulle die nuus b t e f sal ontvang met al die informasie -3ngaande toekomstige vergaderings dlaaslik en internasionaal, asook alle publikasies van beide sasgv en savslor rakende sportwetenskap. may 1986 vol a ansoeke om lidm aatskap m oet gestuur word aan: die sekretaris sasgv/savslor kerkstraat 1131 hatfield pretoria 0083 i i deur aan te sluit by die sascv, word u deel van n groep kollegas metgemeenskapllke doelwitte, nie net plaasllknle, maar ook in die streke en op nasionale en internasionale vlak." wat is die doelstellings van die vereniging? die doelstellings en doelwitte van die vereniging is: • die bevordering van die wetenskap en praktyk van sportgeneeskunde • om navorsing in sportgeneeskunde en sy vertakkings aktief te steun, te bevorder en aan te moedig. • om onderrig en opleiding in sport­ geneeskunde aan te moedig. • om kennis insake die diagnose, voor koming en behandeling van sportbeser ings te bevorder. • om gereelde vergaderings te reel. • om samewerking tussen alle belange groepe in sportgeneeskunde te be werkstellig. • om die belange van sy lede te beskerm. • om die voorafgaande doelstellings te bereik, mag die vereniging subgroepe in die lewe roep, wat kursusse kan reel om die kennis van sportgeneeskunde uit te bou. wat is die voordele van lid­ maatskap van die vereniging? deur lid te word van die sasgv, sal u: • die geleentheid he om gereelde le sings en werkswinkels by te woon insake sportgeneeskunde. • die geleentheid he om aan te sluit by plaaslike subgroepe • die joernaal gereeld ontvang (tydskrif van die sportgeneeskunde-vereniging.) • in staat wees om aktief deel te neem aan die tweejaarlikse nasionale kongres •'n forum he vir persoonlike kontak en die uitruil van gedagtes insake sport­ geneeskunde op 'n nasionale en inter­ nasionale vlak deur die vereniging se as sosiasie met f i m s (federation inter­ nationale de medicine sp ortive-die in­ ternasionale federasie vir sport­ geneeskunde). • geregtig wees op verminderde in skrywingsfooie vir kursusse en kon gresse • deur u lidmaatskap sportgeneeskun­ de in suid-afrika bevorder deur koor dinering van die aktiwiteite van 'n multi professionele span van kundiges. in hierdie joernaal vind u 'n aansoek vorm om lidmaatskap van die vereni­ ging vir u aandag. c a p e tow n v e n u e fo r s p o rts m edicine c o n g re s s the 1987 congress organised by the sa sports medicine association is to be held in cape town from april 14 to 16. details of the programme are still to be finalised, but the main topics will be: • exercise in health and disease. • medical aspects of dance • sports traumatology. at least four international speakers have been invited to participate. further information will be published in future issues of the journal o f the sa sports medicine association. 1, n 0 1,1986 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) (continued from page 15) he manual succeeded in τ structuring the acquisition of new behaviours in a way which encouraged subjects to accept responsibility for complying with the programme both the audio-tape and video-tape failed to do this. besides this, both these devices could have served as external gauges of competence failure to conform to the behaviours observed by the models and/or keep up with the narrator's instructions could have been anxiety-provoking initially-hence the greater amount of time needed to reduce anxiety because these initial negative effects of modelling are not permanent, they cannot be said to be detrimental to the ultimate goal of the treatment, i.e. anxiety reduction. if however, time effective indices are considered, the superiority of the manual is clearly evident: a fast, maximally effective method which maintains a judicious balance between client and helper (inanimate in this case) participation in such a way that the client never perceives the helper as imposing objective or strategies. inferences drawn from these findings should, however, be tentative. problems of experimental design, for example, subject population and the small number of subjects per group, limit the strength of the results. difficulties in measuring the relatively complex phenomena of state and trait anxiety should foster caution in interpreting the results. also, any generalisation of results from an investigation of anxiety in volunteer university students to other anxious individuals should be made cautiously. procedures applicable to severely anxious students may not be applicable or appropriate to more severe anxiety-neurotics. the implications of this study are, however, vast when compared with mainstream psychotherapy and counselling. in our society, seeking counselling or psychotherapy for neurotic anxieties has arguably become a very middleclass activity. many people (without the required opportunity, money and i or intelligence) are denied therapy for anxieties. depth therapy (eg. freudian and neo-freudian) requires clients to have a certain level of intelligence to qualify for intervention. besides this, all therapies are so expensive that only those with the necessary financial resources can afford them. this study suggests that selfadministered exertion therapy, with its simple, cost-effective and readily amendable techniques (as outlined by schomer, 1979), is a valid and viable alternative means of alleviating certain forms of anxiety. it is the hope of the authors that this study will stimulate future research into the area of selfadministered exertion therapy. possible explorations may focus on maintenance of self-administered treatment effects. a worthwhile endeavour for future research would be the development and evaluation of procedural variations and modified instructional formats which would minimise dropout rate-a phenomenon which is notoriously high in self-administered techniques. definitely worth exploring is whether the group setting is a curative factor. subjective evaluation indicated that this was not the case and the authors are of the opinion that working through the treatment programme alone can be equally effective this hypothesis does, however, require further validation. references bellack a s, hersin μ & kazdin a e. (1982). international handbook of behaviour modification and therapy. new york: plenum press. brown ε f (1975). bibliotherapy and its widening applications. new york: metuchen. cattell r b, scheier ι η & madge ε μ (1968). handbook for the ipat anxiety scale and questionnaire national bureau of educational and social research: south african adaptations and norms. pretoria: government printer. de vries η a (1981). tranquilizer effect of exercise: a critical review. physician and sports medicine, november, 9, (11), 47-55. driscoll ρ (1976). anxiety reduction using physical exertion and positive images. psychological record, 26, 86-94. duckitt j & broil τ (1982). personality factors as moderation of the psychological impact of others, south african journal of psychology, 12, 76-80. garfield, s.l. & bergin, a.e. (eds.). (1978). handbook of psychotherapy and behaviour change: an empirical analysis. new york: wiley. glasgow r e, schafer l & o'neill η κ. (1981). selfhelp books and amount of therapist contact in smoking cessation programmes. journal of consulting and clinical psychology, 49, 659-667. glasgow r e s rosen m. (1978) behavioural bibliotherapy. psychological bulletin, 85, 1-23. cross w f. (1966). significant movement in comparatively short-term counselling. journal of counselling psychology, 13, 98-99. hilkey j η & wilheim l. (1982). comparative effectiveness of video-tape pre-training versus no pre-training on selected process and outcome variable in group therapy, psychological reports, 50, 1151-1159. jannoun l. (1982). a self-help treatment programme for anxiety state patients. behaviour therapy, 10,103 -111. kanfer f η & goldstein a p. (eds.). (1980). helping people change. new york: pergamon press. kostrubala, τ. (1976). the joy of running. new york: j β lippincott co. kovel j. (1976). a complete guide to therapy: from psychoanalysis to behaviour modification. great britain: harvester press. croup 1 (manual only) croup 2 (manual plusaudiotape) croup 3 (manual, audiotape plus video) f rrr« ipat scale langner scale poms scale 8 0 -70 6 0 -50 4 0 -30 2 0 1 0 0 +10 + 20 30 7ό o) cl c ο γϊo ' 3 ο ω figure 4: overall average percentage reduction in anxiety level attributable to the amt programme may1986 vol 1,n01,1986 18 why you should become a member of sasma τ he south african sports medicine association, while still in its infancy, is growing in membership. as many potential members would like to know more about the objectives of the association as well as the personal advantages of becoming a member, we would like to explain sasma's aims. by joining sasma you immediately join a fraternity of your colleagues with common goals, not only locally but regionally, nationally and internationally. we have organised an academic forum where ideas, views and experiences can be exchanged on a regular basis. if required, you can be brought into personal contact with a network of colleagues throughout the country.' what is the south african sports medicine association? sasma is a professional body involved in all aspects of sports medicine. since the association is a subgroup of the medical association of sa (masa), its membership is made up of registered medical practitioners of both the public and private sectors who are members of masa. in view of the fact that there are many other interested parties who are not masa members (medical or non-medical disciplines), provision has been made for these parties to become affiliated members of sasma by joining the sports science section of the south african association for sport science, physical education and recreation (saassper). doctors who are not members of masa, physiotherapists, physical educationalists etc. will have to become full members of saassper, their names will come on the mailing list whereby they will receive the newsletters containing all information relating to future meetings locally and internationally as well as other publications of both sasma and saassper relating to sport science. application to become a member of sasma or saassper should be sent to: the secretary sasma/saassper 1131 church street hatfield pretoria 0083 i f by joining sasma you immediatelyjoin a fraternity of your colleagues with common goals, not only locally but regionally, nationally and internationally. ' what,are the objects of the association? these are: •the advancement of the science and art of sport medicine. •to foster, promote, support, augment, develop and encourage investigative knowledge of sports medicine and its ramifications. •to encourage the teaching and education of the same. •to promote the knowledge of recognition, prevention and treatment of sports injuries • to hold and arrange periodic meetings. •to establish and maintain co-operation between medical and other sciences concerned with sports medicine. •to protect the interests of its members. to represent and further the interests of sports medicine and to do all such other things as are incidental to or conducive of the above objects •to accomplish the foregoing objectives, the association may establish subgroups-and shall have.the power to carry on research, and establish courses to the advancement of the knowledge of sports medicine what are the benefits of joining the association? by joining sasma you will: • have the opportunity to attend regular lectures and workshops in sports medicine. • have the opportunity of joining local sub-groups. • receive the journal of the sa sports medicine association • be able to actively take part in the biannual national congress. • have a forum for personal contact and exchange of ideas on a national and international level through the association with f i μ s (federation internationale de medicine sportive-the international federation of sports medicine). • receive reduction of fees for courses and congresses. • promote the advancement of sports medicine in south africa through coordinated efforts by a multidisciplinary team of experts. in this journal you will find an application form for membership for your information. may 1986 v0l1.n01,1986 19 news from the regions ransvaal t s p o rts m edicine c o u rse the executive of sasma is to hold a sports medi­ cine continuing educa­ tion course in johannes­ burg on august 8 and 9. the venue is the bozzoli hall at the university of the witwatersrand. although the course is to be held at general practitioners level, anybody who is interested may attend. topics to be discussed include traum a­ tology. rehabilitation, cardiology, phys­ iology, sports psychology and others. further details will appear in future edi­ tions of the journal ofsa sports medi­ cine association. for further information contact mrs audrey schuster, p 0 box 5539, north­ lands 2116 or telephone (011) 783-6635 western province the western province subgroup has scheduled the following meetings on various sports medicine related topics: may 7 back pain and the athlete dr c du toit-exam ination of the back dr c irving-exercises for the back august 6: the triathlone phenomenon dr c irving-m edical problems dr t d noakes-training principles and equipment dr d p van velden-position on the bike november 6: alternative therapy and the athlete, all meetings will be held at the uct postgraduate medical centre (barnard fuller building, university of cape town medical school, lecture theatre 4). en­ quiries should be directed to dr c irv­ ing tel: (021) 419-1944. abstracts heat illness is approximately the same for men and women during road races the frequency of heat illness is approximately the same for men and women. recent american studies suggest that there are few differences between men's and women's responses to heat stress when they are matched v 0 2 max. dr emily m haymes, associate profes­ sor of movement science and physical education at florida state university in tallahassee, reports that although ear­ ly studies showed that women are less tolerant of exercise in the heat than men, this may have been because the women had lower fitness levels. in hot, humid environments women have an advantage in losing heat be­ cause of their larger-surface-to-weight ratio, even though men lose more sweat," she adds. "training lowers wom­ en's threshold for sweating and im­ proves their tolerance for exercise in the heat. during road races the fre­ quency of heat illness is approximate­ ly the same for men and women. e m haymes the physician and sportsmedicine, vol 12, no 3, march 1984. su id -a frik a a n se s p o rtg e n e e sk u n d e vereniging a p p l ic a t io n f o r m a a n s o e k v o r m full member/voile lid r25 student m ember/studente-lid r5 so u th african s p o rts m edicine a ss o c ia tio n tel no/tel n r ................masa no/mvsa nr full m em ber medical practitioners who are members o f m.a.s.a. voile lid: mediese praktisyns wat lede van die m.vs.a. is. student m em ber medical stu dents in clinical years. sludente-lede: mediese siudem e in hul kliniese jare. appli­ cations for membership of sasma should be sent to: the secretary. sasma. 1131 church st. h aifieid. pretoria. 0083 cheques to accompany membership lorm. may 1986 v 0 l 1 .n 0 1,1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) case report 1 sajsm vol. 29 2017 acute unilateral foot drop as a result of direct blunt trauma to the peroneal nerve in a professional mixed marital arts bout: a case report n k sethi1, md, v khabie2, md 1 department of neurology, new york-presbyterian hospital, weill cornell medical center, new york, ny, usa 2 department of orthopedic surgery, nyu-hospital for joint diseases orthopedic institute, new york, ny, usa corresponding author: n k sethi (sethinitinmd@hotmail.com) case report during the course of a professional mma contest, a 22-year-old fighter was noted to suddenly have a “floppy” left foot which caused him difficulty in maintaining his balance during the fight. a medical timeout was called by the referee and the ringside physician entered the cage to evaluate the fighter. the fighter had a complete left foot drop and a step-off was palpable in the left fibula. however, the fighter denied feeling any pain when palpated along the length of the fibula. the fight was stopped on the advice of the ringside physician as a concern for acute peroneal nerve palsy, associated with a possible fibula fracture, was a possibility. examination in the post-fight area revealed weak ankle dorsiflexion (medical research council [mrc] grade 0/5) and big toe extension (mrc grade 0/5). foot eversion was 0/5, inversion was preserved. ankle and toe plantar flexion, knee flexion, as well as hip abduction, extension, and internal rotation, were normal. weight bearing did not elicit any pain from the fighter. the achilles tendon and patellar reflexes and sensation were not checked. the fighter was immediately transported to the nearest level i trauma centre via ambulance where radiographs revealed no fracture of the fibula. he declined a stretcher and was able to walk to the ambulance aided by his coach and corner staff. discussion foot drop is defined as weakness of the foot and ankle dorsiflexion due to debility of the anterior tibialis, extensor halluces longus and extensor digitorum longus muscles. foot drop can be found as a result of central and peripheral causes. it can occur if there is a disruption anywhere along the neural pathway, from the parasagittal cortical motor neurons to the spinal cord’s upper motor neurons and the peripheral spinal motor neurons, ending with the peroneal nerve. [1] a sciatic and peroneal nerve compromise can occur due to numerous traumatic and non-traumatic causes. traumatic causes may occur in isolation or in association with musculoskeletal injuries involving the hip, knee, fibular head, tibia and the ankle. while acetabular and femur fractures, as well as posterior hip dislocations may compromise the sciatic nerve, the common peroneal nerve may be injured in fractures of the tibia and proximal fibula, and in knee dislocations. in lower extremity injuries, peroneal neuropathy may accompany ligamentous knee injury. ligamentous and bony injuries of the ankle may also result in peroneal neuropathy. [2] the peroneal nerve, due to its superficial course in the leg, is prone to compression as it winds closely around the fibula head and usually presents with a sub-acute and incomplete foot drop. the authors’ presentation of an acute foot drop occurring during a mma fight has not been previously reported. there was no accompanying fracture of the fibula leading to the authors’ hypothesis that in this fighter the cause of the acute foot drop was a blunt trauma, most likely a kick to the lateral aspect of the leg. this resulted in an acute compression neurapraxia, although a more serious injury to the nerve could not be ruled out in the acute setting. a nerve conduction study carried out two to three weeks post injury, especially if recovery is poor or delayed, may aid in prognostication. author contributions: nks conceived, drafted and revised the manuscript, vk reviewed and revised the manuscript. study funding: no targeted funding reported. disclosures: nks serves as associate editor, the eastern journal of medicine. vk reports no relevant disclosures. data sharing statement: the authors have no additional data to share. references 1. kertmen h, gürer b, yimaz er, et al. acute bilateral isolated foot drop: report of two cases. asian j neurosurg 2015;10:123-125. [doi: 10.4103/1793-5482.144596] 2. baima j, krivickas l. evaluation and treatment of peroneal neuropathy. curr rev musculoskelet med 2008;1:147-153. [doi: 10.1007/s12178-008-9023-6] as a result of its superficial location, the peroneal nerve is prone to compression injuries. this is a case report of an acute unilateral foot drop which occurred during a professional mixed martial arts (mma) contest, specifically as a result of direct blunt trauma to the left peroneal nerve, without an accompanying fracture of the fibula. keywords: foot extensor weakness, gait abnormality, contact sports, mixed martial arts s afr j sports med 2017; 29:1. doi: 10.17159/2078-516x/2017/v29i0a3561 mailto:sethinitinmd@hotmail.com https://www.ncbi.nlm.nih.gov/pubmed/?term=kertmen%20h%5bauthor%5d&cauthor=true&cauthor_uid=25972945 https://www.ncbi.nlm.nih.gov/pubmed/?term=g%c3%bcrer%20b%5bauthor%5d&cauthor=true&cauthor_uid=25972945 https://www.ncbi.nlm.nih.gov/pubmed/?term=yimaz%20er%5bauthor%5d&cauthor=true&cauthor_uid=25972945 https://www.ncbi.nlm.nih.gov/pubmed/?term=acute+bilateral+isolated+foot+drop%3a+report+of+two+cases https://www.ncbi.nlm.nih.gov/pubmed/?term=baima%20j%5bauthor%5d&cauthor=true&cauthor_uid=19468889 https://www.ncbi.nlm.nih.gov/pubmed/?term=krivickas%20l%5bauthor%5d&cauthor=true&cauthor_uid=19468889 https://www.ncbi.nlm.nih.gov/pubmed/?term=baima+j+evaluation+and+treatment+of+peroneal+neuropathy http://dx.doi.org/10.17159/2078-516x/2017/v29i0a3561 sajsm vol. 26 no. 2 2014 55 original research objective. the primary aim of this study was to quantify the prevalence of overweight and obesity among urban 7 10-year-old children in affluent (quintile 5) english-medium primary schools in port elizabeth. method. a quantitative, descriptive one-way cross-sectional research design utilising random sampling was used. a once-off survey consisted of anthropometrical assessment of body mass index (bmi) according to standardised procedures. to classify children into weight categories, the international obesity task force z-score bmi cut-off criteria were used. post-hoc analysis consisted of one-way analysis of variance and χ2 tests. level of significance was set at p<0.05. a total of 713 children participated in the study. results. overweight prevalence was 20.9% (n=149) and obesity prevalence was 9.8% (n=70). a significant interaction was found for overweight and obesity levels by gender and age (f=7.2, p=0.01). of the boys (n=372) 18.5% (n=69) were overweight and 6.9% (n=26) were obese. the girls (n=341) had a 23.5% (n=80) overweight rate and 12,9% (n=44) were obese. the highest prevalence of overweight (24.7%, n=43, n=174) was found in children aged 10, and the highest prevalence of obesity (12.5%, n=21, n=167) was found in children aged 8. conclusion. results highlighted the rising prevalence of overweight and obesity among urban children from economically privileged settings. future research into paediatric obesity is needed to curb the growing incidence. s afr j sm 2014;26(2):55-58. doi:10.7196/sajsm.526 obesity in 7 10-year-old children in urban primary schools in port elizabeth j mckersie, ma human movement science (biokinetics); m l baard, dphil department of human movement science and dietetics, nelson mandela metropolitan university, port elizabeth, south africa corresponding author: m l baard (maryna.baard@nmmu.ac.za) the prevalence of excess body weight is becoming a leading threat to the health of children, much more rapid ly in developing countries than in indus trialised ones. the world health organization (who) published a report stating that in 2011, 75% of overweight children were from developing countries.[1] this percentage accounts for 30 million children of 40 million worldwide.[1] south africa (sa) has the highest rate of obesity in sub-saharan africa and the preval ence has doubled from 1990 to 2010.[2] the sa youth risk behaviour survey, 2002 showed that the prevalence of overweight was over 17%, with boys less at risk (6,9%) than girls (25%).[3] results from the health of the nation study indicated that 31.9% of sa children aged 6 to 13 were overweight and 8.1% were obese.[4] overweight and obesity rates of boys were 14.0% and 3.2%, respectively, while 17.9% of girls were rated as overweight and 4.9% as obese.[4] cognisance should be taken of the fact that the study was published 7 years ago. research indicates that obesity in children tends to track into adulthood, unless interventions are put into place at a young age.[5] literature reports that 70 80% of obese adolescents developed into obese adults.[6] associated with childhood obesity are increased risk of non-communicable diseases, decreased quality of life and premature death. [7] according to the who estimates, by 2020 non-communicable dis eases will account for almost three-quarters of all deaths in the developing world.[8] obese children are at risk for chronic disease and are prone to developing insulin resistance, metabolic syndrome, asthma and polycystic ovarian syndrome, and have an increased risk of orthopaedic complications.[6] given the tracking of obesity and asso ciated risk factors, childhood is a key developmental period for early identification and prevention of excessive adiposity.[9] to date, researchers in sa have focused mainly on quantifying undernutrition in rural african children from impoverished settings based on the nutrition transition perspective.[10,11] sa schools are divided into five categories or quintiles, with the poorest schools in quintile 1, and the least poor in quintile 5. this article focuses atten tion on body mass index (bmi) status in urban children in economically privileged (quintile 5) primary schools in port elizabeth. quintile 5 children were assessed to infer a relationship between affluence and obesity prevalence in developing countries. methods a descriptive one-way cross-sectional research design with baseline anthropometric measures of weight and height was used.[12] the nelson mandela metropolitan university (nmmu) research human ethical committee approved the study (h12-hea-hms-002). sampling techniques a list of all the primary schools in the city of port elizabeth was obtained from the nmmu department of education. of the total of 109 schools, 28 met the inclusion criteria of quintile 5, englishmedium primary schools. randomised sampling was used to select 10 schools from which to sample participants. of the 10 schools selected, 4 were included in the study; only 4 of the principals gave permission for their learners to participate in the study. mailto:maryna.baard@nmmu.ac.za 56 sajsm vol. 26 no. 2 2014 participants a total of 713 children in the 7 10-year-old age group were included as the target population. the rationale for inclusion of this age group was that body mass was unlikely to be affected by developmental changes associated with puberty or infancy.[9] a demographic des cription pertaining to age, gender, ethnicity and home language of the participants is presented in table 1. data collection and fieldwork practice a week before the scheduled anthropometric data-gathering date, the class teacher provided participants with a booklet containing questions to be answered by parents or guardians regarding demographic information of age, gender, ethnicity and home language. included were informed-consent and assent forms for children to be signed by the respective parties prior to voluntary participation. anthropometric measures were documented in the booklet. measurements were done in private classroom settings by trained postgraduate research assistants and completed within a 1-month period of appointment times. procedures were explained to participants to reduce any uncertainty or anxiety. children were measured according to school grade, and boys and girls were assessed separately. measuring instruments and procedures the anthropometric instruments for weight and height were calibrated prior to measurement according to the respective manuals. measurements were taken according to the standardised protocol of the american college of sports medicine.[13] anthropometry weight was measured using a scalemaster rs-232c electronic scale, and the readings were noted to the nearest 0.01 kg.[13] the participants were tested while standing upright and motionless in the anatomical zero position, while looking at a fixed point at eye level in the frankfurt plane. they were barefoot and wore minimal clothing. body weight was distributed evenly on both feet. maximum height was measured using a charder hm200pw stadiometer to the nearest 0.1 cm.[13] height was measured from the soles of the feet to the vertex of the head. participants were instructed to stand upright with their heels, gluteal muscles, scapulae and heads touching the vertical surface of the stadiometer. body weight was evenly distributed on both feet and arms were hanging relaxed by their sides, palms facing the thighs. the head was placed in the frankfurt horizontal plane to ensure the vertex of the head was located. the movable block was placed on the vertex of the head and the examiner ensured the frankfurt horizontal plane was kept at all times by holding onto the mandible while the participant in haled maximally. measurement of height was taken after full inhala tion. no hair accessories were worn. bmi bmi was calculated from weight and height measurements (kg/m2). the internationally accepted normative international obesity task force (iotf) cut-off criteria (table 3) were used to quantify obesity and overweight rates among participants.[14] these criteria are based on and linked to the corresponding adult bmi cut-off values used as clinical measures of obesity.[14-16] most of the research evidence in sa, bar the health of the nation study, used arbitrarily defined percentile cut-offs.[4,16] statistical analysis statistica version 9.0 was used for quantitative data analysis.[17] descriptive statistics were used to report on means and standard deviations (sds) for age, gender and bmi status variables (using both normative percentiles and z-scores). one-way analysis of variance (anova) was used to determine whether a difference in overweight and obesity levels existed for age and gender cohorts.[18] post-hoc analysis of results was done by means of χ2 tests.[18] significance was accepted at p<0.05.[18] results the mean (sd) bmi scores for the total group (n=713) is illustrated in table 2. the maximum bmi score recorded was 31.6 kg/m2 and the minimum was 12.6 kg/m2. converted bmi z-scores indicated a mean of 0.4 (0.7); this was done in order to compare re sults to international normative data.[14] the maximum bmi z-score achieved was 2 and table 1. participant characteristics (n=713) n boys girls age (years) 7 90 84 8 81 86 9 109 89 10 92 82 all groups 372 341 ethnicity white 449 black 125 mixed race 91 asian 48 home language english 547 afrikaans 54 isixhosa 108 other 4 table 2. descriptive statistics of bmi for the total group variable n mean (sd) bmi (kg/m2) 713 18.4 (3.2) bmi (iotf) (z-score) 713 0.4 (0.7) boys 372 0.3 (0.7) girls 341 0.4 (0.8) age (years, months) 713 9.0 (1.1) bmi = body mass index; sd = standard deviation; iotf = international obesity task force. sajsm vol. 26 no. 2 2014 57 the minimum was –3. boys and girls obtained average z-scores that placed them in the normal weight category when compared to internationally accepted iotf z-score criteria for bmi classification (table 3).[14] normative criteria[14] and descriptive results (table 3) showed that 65.1% (n=464) of the total group were of normal weight, 20.9% (n=149) were overweight and 9.8% (n=70) were obese. the highest prevalence of overweight (24.7%, n=43, n=174) was found in children aged 10 and the highest prevalence of obesity (12.5%, n=21, n=167) was found in 8-year-old children (table 4). the lowest prevalence of overweight (18.5%, n=31) and obesity (7.4%, n=13) were found in children aged 8 and 10, respectively. posthoc χ2 test results revealed no significant interaction between bmi z-scores for age cohorts as indicated by χ2=13.1, p>0.05. results analysed for gender effect showed that 18.6% (n=69) of the boys (n=372) were overweight and 6.9% (n=26) were obese (table 4). in comparison, 23.5% (n=80) of girls (n=341) were overweight and 12.9% (n=44) were obese. anova yielded a significant difference in bmi iotf z-scores between boys and girls (f=7.2, p<0.05). discussion the prevalence of childhood obesity in developing countries is associated more with children from higher socioeconomic areas than their less economically privileged counterparts.[19] despite the worldwide evidence on the obesity epidemic, there is still a lack of literature on obesity rates among prepubertal urban children in sa from affluent higher socioeconomic areas.[2] findings from this study indicated that most participants were classified as normal or with optimal bmi according to international criteria for growing children. [14] overweight and obesity prevalence rates were 20.9% and 9.8%, respectively. these percentages are consistent with statistics published by the human development index (hdi) for childhood overweight and obesity prevalence in sa, namely 31.8% and 8.1%, respectively.[4,20] comparative differences in prevalence rates reported both here and in the health of the nation study[4] could be attributed to the smaller sample size of this study and the inclusion of 7 10-year-olds from an affluent, eco nomically privileged urban area. the national study surveyed 6 13-year-olds from all socioeconomic strata (n=10 195).[4] challenges arose when making comparisons with sa studies, as only the armstrong et al.[4] study, which used the latest cole et al.[14] iotf bmi grading system, could be found in the literature search. inclusion cri teria for selected sample populations differ across studies; this created further difficulties when contrasting the literature. truter et al.[21] analysed children aged 9 13 years (n=280) from various socioeconomic strata and indicated an overweight and obesity prevalence rate of 15.5% and 6.5%, respectively. kemp et al.[22] analysed the bmi values of 7-year-old children (n=816) from lower socioeconomic areas and reported that 7.8% of the participants were overweight and 3.8% were obese. both of these studies used previous methods of arbitrarily defined percentile cut-offs and smaller sample sizes with variation in variables.[21,22] the perception currently exists that rural children from impoverished environments have lower prevalence of obesity and overweight than their counterparts with higher socioeconomic status;[19] however, more scientific evidence, including studies with larger sample sizes, equivalent variables and the use table 3. bmi criteria (iotf z-scores) and classification of total group iotf z-score grade bmi range at 18 years z-score n % thinness grade 3 (tg3) <16 –3 1 0.1 thinness grade 2 (tg2) 16 <17 –2 5 0.7 thinness grade 1 (tg1) 17 <18.5 –1 24 3.4 normal weight (norm) 18.5 <25 0 464 65.1 overweight (ovw) 25 <30 1 149 20.9 obese (o) 30+ 2 70 9.8 all groups 713 100 bmi = body mass index; iotf = international obesity task force. table 4. bmi criteria (iotf z-score) and classification by age group and gender iotf z-score age (year) 7 8 9 10 all groups classification n % n % n % n % n % gender b g b g b g b g b g b g b g b g b g b g tg3 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1.2 0 1 0 0.3 tg2 0 0 0 0 1 1 1.2 1.2 0 1 0 1.1 1 1 1.1 1.2 2 3 0.5 0.9 tg1 2 1 2.2 1.2 5 3 6.2 3.5 2 5 1.8 5.6 3 3 3.3 3.7 12 12 3.2 3.5 norm 67 54 74.4 64.3 52 53 64.2 61.6 82 47 75.2 52.8 62 47 67.4 57.3 263 201 70.7 59.2 ovw 13 22 14.4 26.2 16 15 19.8 17.4 18 22 16.5 24.7 22 21 23.9 25.6 69 80 18.6 23.5 o 8 7 8.9 8.3 7 14 8.6 16.3 7 14 6.4 15.7 4 9 4.4 11 26 44 6.9 12.9 all groups 90 84 100 100 81 86 100 100 109 89 100 100 92 82 100 100 372 341 100 100 bmi = body mass index; iotf = international obesity task force; b = boy; g = girl; tg = thinness grade; norm = normal; ovw = overweight; o = obese. 58 sajsm vol. 26 no. 2 2014 of internationally accepted bmi criteria, are needed to confirm this trend in sa. the hdi[20] categorises sa as a country in transition, similar to algeria, egypt, china and india; therefore it is relevant to make a comparison with international studies. the hdi[20] reported childhood prevalence rates of 24% overweight and 11.4% obesity in egypt, 10.5% overweight and 7.9% obesity in algeria, and 29.6% overweight and 9.3% obesity in india. westernisation of diet and the availability of inexpensive foods of poor nutritious quality have been linked to increased obesity incidence in children.[23] although kruger et al.[23] found no significant relationship between obesity and the effects of urbanisation, a pattern emerged that showed that urban-dwelling children consumed more calories and had the highest bmi values compared with rural children. these findings were confirmed by data from the sa national food consumption survey, which found that the highest prevalence of overweight children was in urban areas.[23] consistent with the literature,[4,11] significant gender effects were found in the study where girls had higher overweight and obesity rates than boys. of concern is the finding that girls had almost double the obesity rates of boys. this prevalence is higher than data reported in research mentioned earlier.[2-4] possible reasons for gender differences could be lower physical activity levels in girls,[24] and biological and sociocultural differences.[25] conclusions the prevalence of overweight and obesity among preadolescent urban children in an affluent geographic setting was high. children as young as 8 years were found to be obese, more so than 10-yearolds who were overweight rather than obese. this trend is alarming when compared with earlier studies, as young children in this study showed higher bmi levels at an earlier age than previously documented. girls displayed almost double the occurrence of obesity in boys. this growing obesity incidence has escalated rapidly since published results in 2002 in the sa youth risk behaviour survey. in the light of these findings, further research is needed on regional and national patterns in body mass status in young children from all socioeconomic strata, ethnicities, cultures and geographical areas in sa. beyond individual characteristics, the built environment (access to recreational and sport facilities near schools, access to destinations and public transportation, presence of pavements and controlled intersections, the proportion of green space available for active play) has an impact on obesogenic behaviour, and future studies should identify and address the need for developmentally appropriate, focused interventions for specific childhood populations. the recent internationally standardised method of assessment is more appropriate for children younger than 18 years and should be used for comparisons and to monitor secular trends in obesity among children. future studies could expand on the current use of crosssectional experimental designs by doing longitudinal research to guide interventions and educational policies more effectively. the implication for health professionals is to be aware of the modifiable causes of childhood obesity and to implement physical activity, exercise and nutrition management as a primary approach to intervention. acknowledgements. financial assistance was received from the national research foundation and the nmmu as a research grant. references 1. world health organization. obesity and overweight – fact sheet number 311. geneva: world health organization, 2013:1. 2. rossouw h, grant c, viljoen m. overweight and obesity in children and adolescents: the sa problems. s afr j sci 2012;108(5/6):907-914. [http://dx.doi.org/10.4102/sajs.v108i5/6.907] 3. reddy s, panday s, swart d, et al. umthenethe uhlaba usamila: the south african youth risk behaviour survey, 2002. cape town: south african medical research council, 2003. 4. armstrong m, lambert m, sharwood k, lambert e. obesity and overweight in south african primary school children: the health of the nation study. s afr med j 2006;96(5):439-444. 5. li c, ford e, huang t, sun s, goodman e. patterns of change in cardiometabolic risk factors associated with the metabolic syndrome among children and adolescents: the fels longitudinal study. j paediatr 2009;155(3):s5.e9-s9,e16. [http://dx.doi. org/10.1016/j.jpeds.2009.04.046] 6. binkeiwicz-glinska a, bakula s, kusiak-kaczmarek m, et al. obesity prevention in children and adolescents: current recommendations. pol ann med 2012 july;19(2):158162. [htt[://dx.doi.org/10.1016/j.poamed.2012.07.003] 7. kelishadi r. childhood overweight, obesity and the metabolic syndrome in developing countries. epidemiol rev 2007; 29(1):62-76. [http://dx.doi.org/10.1093/epirev/mxm003] 8. world health organization. growth reference 5 19 years: age-for-height and bmi. geneva: world health organization, 2007. 9. santrock j. child development. 11th ed. usa: mcgraw-hill, 2005:165. 10. monyeki k, van lenthe k, steyn n. obesity: does it occur in african children in a rural community of south africa? int j epidemiol 1999; 28(2):287-292. 11. jacobs s, de ridder h. prevalence of overweight and underweight among black south african children from rural areas in the north-west province. south african journal for research in sport, physical education and recreation 2012;34(2):41-51. 12. carter r, lubinsky j, domholdt e. rehabilitation research: principles and applications. 4th ed. usa: elsevier saunders, 2011:56-58. 13. american college of sports medicine. acsm’s guidelines for exercise testing and prescription. 8th ed. london: lippincott, williams and wilkins, 2010. 14. cole t, flegal k, nicholls d, jackson a. body mass index cut offs to define thinness in children and adolescents: international survey. bmj 2007;335:194-197. [http://dx.doi. org/10.1136/bmj.39238.399444.55] 15. august g, caprio s, fennoy h, et al. prevention and treatment of paediatric obesity: an endocrine society clinical practice guideline based on expert opinion. j clin endocrinol metab 2008;93(12):4576-4599. [http://dx.doi.org/10.1210/jc.2007-2458] 16. armstrong m, lambert m, lambert e. secular trends in the prevalence of stunting, overweight and obesity among south african children (1994 2004). eur j clin nutr 2011;65(7): 835-840. [http://dx.doi.org/10.1038/ejcn.2011.46] 17. statsoft. statistica for windows. 8th ed. usa: statsoft, 2008. 18. mendenhall w, beaver r, beaver b. introduction to probability and statistics. 14th ed. boston, usa: brooks/cole cengage learning, 2013. 19. raj m, kumar k. obesity in children and adolescents. indian j med res 2010;132(1):598-607. 20. united nations development programme. human development index (hdi). http:// hdr.undp.org/en/statistics/ (accessed on 9 october 2013). 21. truter l, pienaar a, du toit d. relationships between overweight, obesity and physical fitness of nineto-twelve-year-old south african children. south african family practice 2010:52(3):227-233. 22. kemp c, pienaar a, schutte a. the prevalence of hypertension and the relationship with body composition in grade 1 learners in the north-west province of south africa. south african journal of sports medicine 2011;23(4):117-122. [http://dx.doi.org/10.7196/ sajsm.244] 23. kruger r, kruger h, macintyre u. the determinants of overweight and obesity among 10to 15-year-old school children in the north-west province, south africa: the thusa bana study. public health nutr 2006;9(3):351-358. [http://dx.doi. org/10.1079/phn2005849] 24. ortlieb s, schneider g, koletzko s, et al. physical activity and its correlates in children: a cross-sectional study (the giniplus and lisaplus studies). bmc public health 2013;13:349-363. [http://dx.doi.org/10.1186/1471-2458-13-349] 25. sweeting h. gendered dimensions of obesity in childhood and adolescence. nutr j 2008;7(1):1-14. [http://dx.doi.org/10.1186/1475-2891-7-1] http://dx.doi.org/10.4102/sajs.v108i5/6.907] http://dx.doi.org/10.1016/j.jpeds.2009.04.046] http://dx.doi.org/10.1016/j.jpeds.2009.04.046] http://dx.doi.org/10.1093/epirev/mxm003] http://dx.doi.org/10.1136/bmj.39238.399444.55] http://dx.doi.org/10.1136/bmj.39238.399444.55] http://dx.doi.org/10.1210/jc.2007-2458] http://dx.doi.org/10.1038/ejcn.2011.46] http://hdr.undp.org/en/statistics/ http://hdr.undp.org/en/statistics/ http://dx.doi.org/10.7196/sajsm.244] http://dx.doi.org/10.7196/sajsm.244] http://dx.doi.org/10.1079/phn2005849] http://dx.doi.org/10.1079/phn2005849] http://dx.doi.org/10.1186/1471-2458-13-349] http://dx.doi.org/10.1186/1475-2891-7-1] sajsm vol 20 no. 1 2008 21 introduction human movement and the concomitant increase in energy expenditure are fundamental aspects of human existence. the importance of movement-related energy expenditure has been acknowledged since antiquity but has only relatively recently seen substantial research activity. 7 arguably, the dramatic global increase in chronic diseases of lifestyle over the last century has spurred the interest in exploring the importance of human energy expenditure in relation to health 7 and has led to evidence-based public health guidelines for health-enhancing physical activity. 13 a number of instruments are available for estimating human energy expenditure and range from paper and pencil methods to doubly-labelled water. 20,28 irrespective of the method employed, it is important that the sources and magnitude of the variability of physical activity are quantified so that research activities in physical activity and health are appropriately designed, analysed and interpreted. 28 by partitioning physical activity variability into discrete components, the number of periods of monitoring required to reliably estimate physical activity volumes and patterns of individuals in a population can be determined. 28 importantly, the number of periods of monitoring will influence aspects of study design such as sample size and statistical power. 28 it should be noted that assessments of energy intake (diet) and energy expenditure (physical activity) are susceptible to the same types of measurement error. 16 numerous studies in industrialised countries have investigated the reliability of objectively monitored freeliving physical activity. 3,8-11,14-16,21,24-27 however, few papers have reported sources of variation for either physical activity questionnaires 14,17,18 or objectively monitored physical activity. 15 within the south african context there is a dearth of reliability studies for any form of physical activity assessment. 2,4,5,12 the reliability of objectively monitored free-living physical activity in south african samples has not been reported. moreover, no data have been reported regarding the sources of variation for any type of physical activity measurement instrument in south african samples. from a regional and international perspective, we are not aware of any data from sub-saharan africa or any developing original research article sources of variance and reliability of objectively monitored physical activity in rural and urban northern sotho-speaking blacks abstract objectives. we investigated the sources of variance and reliability in an objective measure of physical activity for a 14hour and 4-day monitoring period. design. a convenience sample of rural (n=31) and urban (n=30) adult, northern sotho-speaking blacks was recruited. physical activity was assessed for 8 consecutive days using a uni-axial accelerometer. physical activity indices were total counts, average counts, inactivity (<500 counts) moderate1 activity (500 1 951 counts), moderate-2+vigorous activity (≥1 952 counts), and were expressed per hour or per day as required. results. accelerometry data from 41 subjects (23 males, 18 females) complied with selection requirements and were analysed for variance distribution and reliability (intraclass correlation coefficients (iccs)). for the 14-hour monitoring period variance was distributed as follows: intra-individual (71 82%), inter-individual (3 18%) and hour-of-day (2 14%). attenuated iccs ranged from 0.31 to 0.75 (median: 0.70). variance for the 4-day monitoring period differed from the 14-hour monitoring period: inter-individual (47 58%), intraindividual (43 51%) and day-of-week (0 6.5%). attenuated iccs ranged from 0.27 to 0.84 (median: 0.79). irrespective of the monitoring period, total counts, average counts and moderate-2+vigorous activity tended to be the most reliable measures requiring the fewest number of monitoring periods. conclusions. these findings provide an insight for understanding how variance is distributed in objectively measured activity patterns of a south african sample and show that relicorrespondence: ian cook physical activity epidemiology laboratory university of limpopo (turfloop campus) po box 459 fauna park 0787 polokwane south africa tel+fax: +27 15 268 2390 e-mail: ianc@ul.ac.za ian cook (ba (phys ed) hons, bsc (med) hons)1 estelle v lambert (phd)2 1 physical activity epidemiology laboratory, university of limpopo (turfloop campus), south africa 2 mrc/uct research unit for exercise science and sports medicine, university of cape town medical school, south africa able measures of adult physical activity behaviours require 18 128 hours and 3 44 days, depending on the monitoring period, physical activity index, residence status and sex. pg21-27.indd 21 4/23/08 11:32:03 am 22 sajsm vol 20 no. 1 2008 country that have addressed variance distribution and reliability of objectively monitored free-living physical activity. reliability and variance distribution have been widely investigated within nutritional epidemiology 22,23,29 but less so in physical activity measures that are often used to estimate physical activity patterns and energy expenditure. 28 this is probably because of the relatively recent emergence of a new branch of epidemiology, namely physical activity epidemiology. 7 considering the heterogeneity of the south african population, studies investigating the variance distribution and reliability of physical activity assessments across sub-sections of the south african population are required. the objective of this paper was firstly to investigate the sources and distribution of variance for objectively measured physical activity over a number of hours and days in a sample of rural and urban northern sotho-speaking blacks. the second objective was to determine the number of hours and days required to reliably measure 1 hour and 1 day of accelerometerderived indices of physical activity in this particular south african sample. methods study protocol the data used in this analysis were collected during the validity trial of the international physical activity questionnaire (ipaq) which has been reported elsewhere. 2,5 for this analysis only the accelerometer data were considered. briefly, black northern sotho-speaking rural and urban participants were recruited and contacted twice over an 8-day period. on the first occasion, subjects were recruited, completed a socio-demographic questionnaire and provided anthropometric data. all interviews and anthropometric measures were conducted by trained black male and female field workers. anthropometric measures included body mass (kg) and stature (cm) allowing the calculation of body mass index (bmi, kg.m -2 ). finally, subjects were instructed on the necessary procedures for wearing the accelerometer. eight days later the accelerometers were collected. subjects received a small honorarium on completion of the study. signed informed consent was obtained from all participants. the study was approved by the ethics committee of the university of limpopo (turfloop campus). subjects rural sample a convenience sample of black employees, resident on farms and villages, were recruited from the plantation section of a local lumber mill situated in the limpopo province, south africa (total n=31, males n=18, females n=13). these workers performed a variety of manual tasks and ensured that plantations were created and maintained, and that raw timber was harvested, sized, cleaned and stacked prior to transport to the saw mill for further processing. urban sample a convenience sample was recruited from black academic staff, support staff and students of the university of the limpopo (turfloop campus), and black residents (office workers, teachers) from the surrounding community (mankweng) and nearby city (polokwane) (total n=30, males n=14, females n=16). for the most part, these subjects performed tasks typical of office workers, with long periods of sedentary activity (sitting, standing quietly). physical activity counts and durations to objectively quantify free-living physical activity of the subjects, uni-axial accelerometers were worn for at least 8 days. the csa model 7164 (computer science applications, inc. shalimar, fl), now marketed as the mti actigraph (mti health services, fort walton beach, fl), is small and unobtrusive (5.1 cm x 4.1 cm x 1.5 cm, 42.6 g). 28 in this study, the epoch duration was set at 1 minute. the accelerometer was worn on the right waist, securely attached to a nylon belt. the accelerometers could be removed for sleeping and bathing purposes by unclipping the nylon belt. the data were downloaded from the accelerometers onto an ibm-compatible personal computer via an interface unit, for further analysis using csa-supplied software (daybyday. xls, microsoft excel©97 macro) and a customised data reduction programme (microsoft excel©97 macro). physical activity counts were defined as total counts (counts.day -1 ) and average counts (counts.min-1.day -1 ). physical activity intensity patterns or durations (min.day -1 ) of inactivity and moderate and vigorous activity were created according to cut-points defined by matthews et al. 15 inactivity (sitting, standing quietly) was defined as less than 500 counts.min -1 . for moderate activity (3-6 mets, 1 met = 1 metabolic equivalent = 3.5 mlo2.kg -1 .min -1 = 1 kcal.kg -1 .hr -1 ) a distinction was made between activities requiring less ambulation (moderate-1: house work, yard work) and predominantly ambulatory activities (moderate-2: walking). the cut-points for moderate-1 and moderate-2 were defined as 500 1 591 counts.min -1 and 1 592 5 724 counts.min -1 , respectively. activities, such as running, which record more than 5 724 counts.min -1 were defined as vigorous (>6 mets). the first and last days of the 8-day monitoring period were excluded. to evaluate the number of hours required to reliably estimate 1 hour of objectively monitored physical activity, the first weekday with at least 14 hours of registration (06h00 to 20h00) was selected. to evaluate the number of days required to reliably estimate 1 day of objectively monitored physical activity, accelerometer data for 4 days (3 weekdays and 1 weekend day) were used. only days with at least 10 hours.day -1 (600 minutes. day -1 ) of registration were included. 5 from the minute-by-minute data, hourly and daily accelerometry indices were summed (counts.hour -1 , counts.day -1 , minutes.hour -1 , minutes.day -1 ). accelerometry data of 41 subjects (23 males, 18 females) which constituted 67.2% of the original sample of 61, complied with all the selection criteria. statistical analysis the descriptive analysis comprised residence-specific means and standard deviations and percentages for continuous and categorical variables, respectively. for skewed continuous accelerometry variables (≥2x standard deviation), residence-specific medians and interquartile ranges were calculated. differences (rural v. urban) between two independent categorical variables were tested for significance (with continuity correction for small sample sizes). 1 to examine differences (rural v. urban) between two independent continuous variables, an independent t-test was used. because the distributions of some variables were neither normal nor lognormal a comparable non-parametric test was used (mann-whitney u test). pg21-27.indd 22 4/23/08 11:32:04 am sajsm vol 20 no. 1 2008 23 hourly (14 hours) and daily (4 day) accelerometry indices were rank transformed because the distributions of several residencespecific accelerometer indices were neither normal nor lognormal. to evaluate the sources of variability in ranked accelerometer data, variance components in mixed and random effects models were estimated using restricted maximum likelihood methods. 15 accelerometer indices were the dependant variables for these analyses. variance components were estimated for subject (interindividual) variance, trial (hour or day) variance, and residual (intra-individual) variance. the variance components were also expressed as a percentage of the total variance. inter-individual variance represents true variation between subjects while intraindividual variance represents hour-to-hour or day-to-day variation within subjects. the variance due to the hour or day effect was nested within subjects. to identify variables that could affect the inter-individual variance and thus the reliability we entered age, body mass index, educational level, residence (rural/urban) and sex (male/female) individually as fixed factors. from this preliminary analysis (data not shown) we identified residence and sex as having the most consistent and substantial impact on interindividual variance. the first analysis was conducted on the whole sample such that variance components for subject, trial (day or table i. descriptive characteristics for rural and urban subjects residence rural urban p ‡ continuous variables (n = 21) (n = 20) age (years) 38.9 (10.4) 32.9 (6.7) 0.037 bmi (kg.m -2 ) 22.9 (3.9) 27.2 (5.3) 0.006 accelerometer data (4-day average) activity counts (cts) total counts (cts.day -1 ) 644 102 (208 420) 409 341 (169 799) 0.001 average counts (cts.min-1.day -1 ) 847 (267) 618 (248) 0.008 duration (min.day -1 ) inactivity (0 499 cts) 1 078 (92) 1 236 (58) <0.001 moderate 1 (500 1 951 cts) 265 (67) 141 (35) <0.001 moderate 2 – vigorous (>1 951 cts) * 94 (55) 51 (65) 0.027 categorical variables † body mass index classification normal weight (<25 kg.m -2 ) 76.2 (16) 40.0 (8) 0.042 overweight to obese (≥25 kg.m -2 ) 23.8 (5) 60.0 (12) 0.042 female participants 47.6 (10) 40.0 (8) 0.860 education (≥grade 12) 0 (0) 85.0 (17) <0.001 ownership of motor vehicle (yes) 14.3 (3) 40.0 (8) 0.132 electricity available inside house (yes) 19.0 (4) 85.0 (17) <0.001 data are reported as mean (sd) for all continuous variables except * median (interquartile range) and categorical variables † % (n), ‡ p values evaluate rural v. urban differences. table ii. crude and adjusted intrato inter-subject variance ratios (σ2w /σ 2 b) by monitoring period σ 2 w /σ 2 b ratio variables * crude † adjusted ‡ % change § 14-hours (n = 41) total counts 3.44 7.06 105.0 average counts 3.80 7.29 91.6 inactivity 3.09 9.07 193.2 moderate-1 2.75 11.34 312.8 moderate-2+vigorous 3.41 5.35 56.9 4-days (n = 41) total counts 0.66 1.01 53.6 average counts 0.55 0.73 33.6 inactivity 0.58 1.53 163.0 moderate-1 0.67 2.49 269.9 moderate-2+vigorous 0.77 1.04 35.6 * see table ι for variable units, † unadjusted for fixed effects of residence and sex, ‡ adjusted for fixed effects of residence and sex, § % change = [(adjusted – crude)/crude] x 100. pg21-27.indd 23 4/23/08 11:32:05 am 24 sajsm vol 20 no. 1 2008 hour) and residual were extracted with and without adjustment for fixed effects of residence and sex. from the extracted variance components, intrato inter-subject variance ratios (σ2w /σ 2 b) were calculated, where σ2b was the between or inter-individual variance and σ2w was the withinor intra-individual variance. to examine possible differences in the distribution of variance (inter-individual, hour or day effect, residual) across residence status, the second analysis was stratified by residence while treating sex as a fixed factor. reliability coefficients were calculated from the variance components extracted from the residence-stratified variance component analysis, with sex treated as a fixed factor. reliability was calculated as an average measure (iccm) and a single measure (iccs) intraclass correlation coefficient (icc) using the following equations, iccm = σ 2 b / (σ 2 b + σ 2 w) and iccs = σ 2 b / (σ2b +σ 2 w / k), where σ 2 b was the inter-individual variance, σ 2 w was the intra-individual variance and k was the number of days or hours. 19 because unbounded, ranked data were used to obtain an icc from a model meant for continuous data, 6 the corrected and uncorrected iccm from the mean squares of an anova-based variance component analysis were also calculated. 19 there was no difference in iccm after the correction (data not shown). deattenuated 4-day and 14-hour iccm were calculated using the formula, icctrue = iccobs x (1 + [σ 2 w / σ 2 b] / k) 0.5 where icctrue was the true correlation, iccobs was the observed correlation, σ2w was the intra-individual variance, σ 2 b was the inter-individual variance and k the number of monitoring periods. 16,28 because random variation (intra-individual variance) reduces the ability to identify significant effects, deattenuation is employed to adjust for random variation such that a better estimate is obtained of the true statistic. to estimate the number of hours and days required to reliably predict 1 hour and 1 day of accelerometry, respectively, the following equation was rearranged to solve for k, icc = σ2b / (σ 2 b +σ2w / k) were icc = 0.80. data were analysed using appropriate statistical software (spss for windows 11.0.1). significance for all inferential statistics was set at p<0.05. results subject characteristics are reported in table i. because of the relatively low volume and highly skewed distribution of the recorded vigorous activity (rural: 3.7±6.7 min v. urban: 3.2±5.3 min), the moderate-2 and vigorous variables were combined. significant differences were found between rural and urban groups for all continuous and categorical variables, except for sex distribution and vehicle ownership. of note were the significantly lower levels of obesity and inactivity, and greater levels of activity in the rural group compared with the urban group. crude and adjusted variability ratios (σ2w /σ 2 b) for accelerometer indices are reported in table ii. both crude and adjusted variability ratios were far higher for hourly accelerometer variables compared with daily accelerometer variables. after adjustment for residence and sex, the variability ratios increased for both 14-hour and 4day accelerometer variables by 34 313%, although the increases were greater for the 14-hour period compared with the 4-day period. adjustment for residence and sex reduced the interor between-subject variability (σ2b), thereby increasing the ratio. the higher ratios mean that more periods of objective physical activity monitoring would be required to reliably predict physical activity, especially so for hour-by-hour accelerometer indices. total variance in each of the 14-hour accelerometer indices was higher in the urban sample, suggesting that the distribution of activity and inactivity levels in the urban sample was more heterogeneous compared with the rural sample (table iii). for both groups intra-individual variability was the largest source of variance (71 82%). the distribution of inter-individual and hour of day variability differed between the rural and urban group. in the rural group, hour of day variability was the second highest source of variance (15 18%), followed by inter-individual variability (3 14%). in contrast, for the urban group, inter-individual variability was the second highest source of variance (14 18%), followed by hour of day variability (2 7%). unlike the 14-hour accelerometer variability, total variance for the 4-day period was not consistently higher in the rural or urban group (table iv). in the rural group, inter-individual variance (47 58%) tended to be slightly higher than intra-individual variance (43 51%), while day of week variability was lowest (0 6.5%) of all sources of variance. for accelerometer counts and moderate2+vigorous activity level, variance distribution in the urban group mirrored that of the rural group; 49 57% inter-individual, 44 51% intra-individual and 0 2% day of week. in contrast, the urban group intra-individual variance for inactivity and moderate-1 levels were high compared with inter-individual variance: 69 91% v. 8 31%, respectively. attenuated reliability coefficients for 14-hour accelerometer indices were less than 0.8 and were lower in the rural group compared with the urban group (table v). hourly moderate2+vigorous activity was the most reliable for both the rural and urban groups. the most unreliable accelerometer indices were the inactivity and moderate-1 levels in the rural group. excluding the two lowest reliabilities, the attenuated reliability coefficients increased by 0.12 to 0.19 units after accounting for intra-individual variation, while the reliability coefficients for the inactivity and moderate-1 indices increased by ~0.23 units after deattenuation. the difference between rural and urban reliability remained even after deattenuation of all the reliability coefficients. to achieve a reliability coefficient of 0.8 for hourly accelerometer variables in the urban group would require approximately 2 periods of 12-hour monitoring (24 hours). in contrast, approximately 4 11 periods of 12-hour monitoring (48 130 hours) would be required in the rural group. in both groups, moderate-2+vigorous activity required fewer hours of monitoring to reliably predict 1 hour of activity (19 24 hours) compared with other accelerometer indices. the reliability of 4-day accelerometer indices was generally higher compared with the 14-hour accelerometer variables (table vi). attenuated reliability coefficients in both the rural and urban groups were nearly identical except for the low reliability coefficients for inactivity and moderate-1 indices in the urban group. the values of 8 of the 10 attenuated reliability coefficients increased by 0.08 0.10 units after accounting for the intraindividual variation. the effect of deattenuation was not greater in the rural group (mean difference = 0.10 units) or the urban group (mean difference = 0.09 units) for 8 of the 10 reliability coefficients. because of the higher intra-individual variation in the inactivity and moderate-1 activity indices of the urban group, the attenuated reliability coefficients increased by 0.16 to 0.48 units. in the rural group, at least 5 days of monitoring would be required to reliably predict one day of activity or inactivity. however, in the urban group, to reliably predict one day of inactivity, moderate-1 activity and moderate-2+vigorous activity would require 9, 44 and 4 days of monitoring, respectively. pg21-27.indd 24 4/23/08 11:32:07 am sajsm vol 20 no. 1 2008 25 discussion this study is novel for two reasons. it is the first analysis that has reported on the reliability of objectively monitored physical activity in a south african setting. it is also the first analysis that has investigated the distribution of variance for any physical activity measure in a south african sample. the principal findings of this analysis were firstly that the distribution of variance differed depending on the sampling period. for the 4-day sampling period, betweenor inter-subject variability, which represents true differences in physical activity indices between subjects, was at least as large as withinor intra-individual variability (behavioural variability), while day of week accounted for little of the variance (<7%). in contrast, for the 14-hour monitoring period, intra-individual variation accounted for more than 70% of the variance, while hour of day and inter-individual variation accounted for the remaining variance. secondly, irrespective of the monitoring period (14-hour or 4-day), total counts, average counts and moderate-2+vigorous activity tended to be the most reliable measures requiring the fewest number of monitoring periods. thirdly, adjustment for basic demographic factors such as residence and sex prevents the under-estimation of monitoring days required so that reliable estimates of physical activity volumes and patterns can be obtained. the authors are not aware of any other analysis investigating the reliability and variance distribution of accelerometry data collected in adult populations over monitoring periods shorter than a day. the results from the 14-hour monitoring period of the present study show that a reversal in variance distribution occurs in comparison to the 4-day period; intra-individual variance > inter-individual variance. moreover, the relative contributions of the inter-individual variance and hour of day variance to the total variance were contrasted in the two residence-defined groups. this can be explained by the fact that the physical activity patterns in the rural group show relatively large changes over the course of the 14 hours, ranging from physical inactivity in the morning to being physically active during the working day, which is interspersed with breaks (tea, lunch), and back again to physically inactive levels during the late afternoon and evenings. this type of hourly activity pattern was quite homogenous throughout the rural group such that inter-individual variance was lower. in contrast, the activity patterns of the urban group tended to remain relatively constant over the period of the 14 hours, although this could differ between individuals, which explains the higher inter-individual variance in this group. it is likely then that similar investigations of hourly physical activity patterns in different samples will yield variance distributions that are in accord with the particular activity demands required of those samples. importantly, the number of periods required to reliably estimate physical activity volumes and patterns will differ from sample to sample, particularly over shorter monitoring periods where variance contrasts between groups can be large. the greater intra-individual variance in the 14-hour monitoring period, although in accord with the variance distribution in questionnaire-based physical activity assessment cannot be because of factors related to the imprecision of measurement found in non-objective physical activity assessment. 17 rather, the greater intra-individual variance could be due to the natural variation in physical activity behaviour from hour to hour. the results for the 4-day monitoring period are generally in agreement with data from north america in that inter-individual variation accounted for most of the variation. 15 matthews et al. examined accelerometry data collected from 92 adults over a period of 21 consecutive days. 15 they found inter-individual variation contributed the most to overall variance (55 60%) followed by intra-individual variance (30 45%) and day of the week variance (1 8%). the number of days required to achieve 80% reliability for estimating activity counts and moderate2+vigorous activity was 3 4 day, 15 which is in agreement with the present results of 4 5 days. moreover, the north american data also found that estimating physical inactivity was more t a b l e i ii . v a ri a n c e c o m p o n e n t a n a ly s is o f th e 1 4 -h o u r a c c e le ro m e te r o u tp u t in r u ra l a n d u rb a n s u b je c ts a c ti v it y c o u n ts * a c ti v it y d u ra ti o n * s o u rc e s o f t o ta l c o u n ts a v e ra g e c o u n ts i n a c ti v it y m o d e ra te -1 m o d e ra te v a ri a n c e † 2 + v ig o ro u s v a ri a n c e % v a ri a n c e % v a ri a n c e % v a ri a n c e % v a ri a n c e % r u ra l ( n = 2 1 ) i n te rin d iv id u a l 1 6 6 9 8 .1 1 6 7 2 8 .1 1 0 2 2 4 .5 6 7 0 3 .0 3 3 1 7 1 4 .4 h o u r o f d a y 3 4 8 3 1 6 .9 3 3 7 6 1 6 .3 4 0 5 2 1 7 .7 3 6 3 5 1 6 .5 3 3 6 0 1 4 .6 i n tr a -i n d iv id u a l 1 5 4 7 1 7 5 .0 1 5 6 5 6 7 5 .6 1 7 7 6 2 7 7 .8 1 7 7 2 6 8 0 .5 1 6 2 9 8 7 0 .9 t o ta l 2 0 6 2 3 1 0 0 2 0 7 0 3 1 0 0 2 2 8 3 6 1 0 0 2 2 0 3 1 1 0 0 2 2 9 7 4 1 0 0 u rb a n ( n = 2 0 ) in te rin d iv id u a l 4 9 1 2 1 6 .9 4 8 0 2 1 6 .1 3 9 9 8 1 6 .6 3 2 3 3 1 4 .4 4 7 4 5 1 7 .8 h o u r o f d a y 1 7 1 2 5 .9 5 9 4 2 .0 1 5 6 5 6 .5 1 3 9 0 6 .2 1 3 11 4 .9 in tr a -i n d iv id u a l 2 2 4 7 7 7 7 .2 2 4 4 1 4 8 1 .9 1 8 5 3 9 7 6 .9 1 7 9 0 4 7 9 .5 2 0 6 2 2 7 7 .3 to ta l 2 9 1 0 1 1 0 0 2 9 8 1 0 1 0 0 2 4 1 0 1 1 0 0 2 2 5 2 7 1 0 0 2 6 6 7 8 1 0 0 * se e t a b le ι f o r u n its , † a d ju st e d f o r fix e d e ff e ct s o f se x, % s o u rc e s o f va ri a n ce a s a p e rc e n ta g e o f to ta l v a ri a n ce . pg21-27.indd 25 4/23/08 11:32:08 am 26 sajsm vol 20 no. 1 2008 unreliable requiring more days of monitoring compared to most of the physical activity indices (7 days) and is in agreement with our finding of 5 10 days in the present results. the difference between inter-individual and intra-individual variance in the present study was not as pronounced as found by matthews et al. 15 but is still quite different to the variance distribution found in questionnaire-based physical activity assessment (50 60% intraindividual, 20 30% inter-individual). 18 it has been suggested that the differences in variance distribution between objective and self-reported physical activity assessment may be due to factors such as precision of objective measuring instruments, the ability of objective measuring instruments to detect common, light intensity activities and the level of variability present in selfreport instruments. 15 the results of the present investigation also accord with the prediction of matthews et al. that because of the differences between study samples in terms of variance distribution, each study sample would have different sampling requirements. 15 the present results have shown general agreement in that interindividual variance is at least as great as intra-individual variance. specific differences have also been shown in the present study, in that the differences between inter-individual and intra-individual variances are not as pronounced as those found by others. 15 consequently, the number of days required to reliably estimate the various physical activity and inactivity indices differ from that proposed by others. 15 the predicted qualitative differences between our results from those of others 15 would appear to add further support the validity of the present analysis. it would certainly be profitable to analyse the larger south african accelerometry dataset that was part of the ipaq validation study, especially because of the heterogeneity of the south african population. this dataset contains accelerometry data from a relatively large sample of subjects (n>100) differing in age, body composition, education level, ethnicity, fitness, language, residence, sex, and socio-economic status. the examination of the reliability and the variance distribution of this dataset would provide valuable information for the south african researcher. there is a lack of published information regarding the number of days of objectively monitored physical activity that would be required to reliably estimate objectively measured physical activity levels and patterns in specific sub-sections of the south african population. the strength of the present study is firstly the uniqueness of the analysis within a south african context, which will hopefully provide further motivation and impetus for more analyses of this kind. secondly, this analysis provides reliability and variance estimates for a south african sample of a particular ethnicity, t a b l e i v . v a ri a n c e c o m p o n e n t a n a ly s is o f th e 4 -d a y a c c e le ro m e te r o u tp u t in r u ra l a n d u rb a n s u b je c ts a c ti v it y c o u n ts * a c ti v it y d u ra ti o n * s o u rc e s o f t o ta l c o u n ts a v e ra g e c o u n ts i n a c ti v it y m o d e ra te -1 m o d e ra te v a ri a n c e † 2 + v ig o ro u s v a ri a n c e % v a ri a n c e % v a ri a n c e % v a ri a n c e % v a ri a n c e % r u ra l ( n = 2 1 ) i n te rin d iv id u a l 8 6 4 5 0 .1 9 6 7 5 7 .5 7 5 6 4 7 .3 6 8 0 4 4 .7 9 2 9 4 8 .9 d a y o f w e e k 1 1 0 .6 0 0 .0 6 1 3 .8 9 9 6 .5 0 0 .0 i n tr a -i n d iv id u a l 8 4 8 4 9 .2 7 1 3 4 2 .5 7 8 0 4 8 .8 7 4 3 4 8 .8 9 7 0 5 1 .1 t o ta l 1 7 2 2 1 0 0 1 6 8 0 1 0 0 1 5 9 7 1 0 0 1 5 2 1 1 0 0 1 8 9 9 1 0 0 u rb a n ( n = 2 0 ) i n te rin d iv id u a l 9 0 6 4 8 .6 1 1 8 3 5 6 .5 3 7 5 3 0 .8 9 1 8 .4 9 7 5 4 9 .0 d a y o f w e e k 0 0 .0 0 0 .0 0 0 .0 3 0 .3 4 5 2 .3 i n tr a -i n d iv id u a l 9 5 9 5 1 .4 9 1 0 4 3 .5 8 4 2 6 9 .2 9 9 9 9 1 .3 9 7 0 4 8 .7 to ta l 1 8 6 5 1 0 0 2 0 9 3 1 0 0 1 2 1 7 1 0 0 1 0 9 3 1 0 0 1 9 9 0 1 0 0 * s e e t a b le i f o r u n its , † a d ju st e d f o r fix e d e ff e ct s o f se x, % s o u rc e s o f va ri a n ce a s a p e rc e n ta g e o f to ta l v a ri a n ce . table v. intraclass correlation reliability analysis of 14-hour accelerometer output indices in rural and urban subjects reliability required number (icc) of hours to achieve a reliability of 0.8 variables * 14 hours † 1 hour rural (n = 21) total counts 0.55 (0.74) 0.08 45.4 average counts 0.55 (0.74) 0.08 45.5 inactivity 0.40 (0.63) 0.04 85.4 moderate-1 0.31 (0.55) ‡ 0.03 127.6 moderate 0.70 (0.84) 0.14 23.7 2+vigorous urban (n = 20) total counts 0.74 (0.86) 0.17 19.7 average counts 0.73 (0.85) 0.16 20.8 inactivity 0.74 (0.86) 0.17 20.1 moderate-1 0.70 (0.84) 0.14 23.9 moderate 0.75 (0.87) 0.18 18.5 2+vigorous * see table i for variable units, icc = intraclass correlation coefficient, † deattenuated iccm appear in parenthesis, all icc significant (p < 0.05) except ‡ (p=0.1036). pg21-27.indd 26 4/23/08 11:32:09 am sajsm vol 20 no. 1 2008 27 language and residence status. the weakness of this study is the relatively low number of subjects. however, the fact that our results concur generally and differ specifically, as expected, with the results of a similar, larger analysis, 15 suggests that despite the relatively small sample size the results of the present analysis are valid. it should also be noted that some of the stratified random effects analyses performed by matthews et al. were done on sample sizes as low as 14. 15 in conclusion, this analysis has provided quantitative estimates of the reliability and distribution of variance of objectively measured physical activity measures in a specific ethnic and language group, over two monitoring periods (14hour and 4-day). further analyses using larger sample sizes and in different sub-sections of the south african population are required for both questionnaire-based and objectively measured physical activity indices. acknowledgements we are indebted to the study participants and field workers for their sustained and friendly co-operation, and to mr trevor phillips who kindly arranged access to the forestry and factory staff at steven’s lumber mills. the research development and administration division of the university of limpopo (turfloop campus) and the research capacity development group of the medical research council of south africa supported this study. references 1. altman dg. practical statistics for medical research. boca raton: chapman and hall/crc, 1999. 2. bohlmann im, mackinnon s, kruger s et al. is the international physical activity questionnaire (ipaq) valid and reliable in the south african population? med sci sports exerc 2001; 33: s119. 3. coleman kj, epstein lh. application of generalizability theory to measurement of activity in males who are not regularly active: a preliminary report. res q exerc sport 1998; 69: 58-63. 4. cook i, lambert ev. validity and reliability of the international physical activity questionnaire in northern sotho-speaking africans. jemdsa 2002; 7: s36. 5. craig cl, marshall al, sjostrom m, et al. international physical activity questionnaire: 12-country reliability and validity. med sci sports exerc 2003; 35: 1381-95. 6. de mast j, van wieringen w. measurement system analysis for bounded ordinal data. qual reliab engng int 2004; 20: 383-95. 7. dishman rk, washburn ra, heath gw. physical activity epidemiology. champaign, il: human kinetics, 2004. 8. durant rh, baranowski t, davis h, et al. reliability and variability of indicators of heart-rate monitoring in children. med sci sports exerc 1993; 25: 389-95. 9. durant rh, baranowski t, davis h, thompson wo, puhl j, greaves ka, rhodes t. reliability and variability of heart rate monitoring in 3-, 4-, or 5-yrold children. med sci sports exerc 1992; 24: 265-71. 10. gretebeck rj, montoye hj. variability of some objective measures of physical activity. med sci sports exerc 1992; 24: 1167-72. 11. janz kf, witt j, mahoney lt. the stability of children’s physical activity as measured by accelerometry and self-report. med sci sports exerc 1995; 27: 1326-32. 12. kruger hs, venter cs, steyn hs. a standardised physical activity questionnaire for a population in transition: the thusa study. afr j phys health educ recreat dance 2000; 6: 54-64. 13. lambert ev, bohlmann i, kolbe-alexander t. ‘be active’ physical activity for health in south africa. s afr j clin nutr 2001; 14: s12-s16. 14. levin s, david r, ainsworth be, richardson mt, leon as. intra-individual variation and estimates of usual physical activity. ann epidemiol 1999; 9: 481-8. 15. matthews ce, ainsworth be, thompson rw, bassett dr. sources of variance in daily physical activity levels as measured by an accelerometer. med sci sports exerc 2002; 34: 1376-81. 16. matthews ce, freedson ps, hebert jr, stanek ej, merriam pa, ockene is. comparing physical activity assessment methods in the seasonal variation of blood cholesterol study. med sci sports exerc 2000; 32: 976-84. 17. matthews ce, freedson ps, hebert jr, et al. seasonal variation in household, occupational, and leisure time physical activity: longitudinal analyses from the seasonal variation of blood cholesterol study. am j epidemiol 2001; 153: 172-83. 18. matthews ce, hebert jr, freedson ps, et al. sources of variance in daily physical activity levels in the seasonal variation of blood cholesterol study. am j epidemiol 2001; 153: 987-95. 19. mcgraw ko, wong sp. forming inferences about some intraclass correlation coefficients. psychol methods 1996; 1: 30-46. 20. montoye hj, kemper hcg, saris whm, washburn ra. measuring physical activity and energy expenditure. champaign, il: human kinetics, 1996. 21. murray dm, catellier dj, hannan pj, et al. school-level intraclass correlation for physical activity in adolescent girls. med sci sports exerc 2004; 36: 876-82. 22. nyambose j, koski kg, tucker kl. high intra/interindividual variance ratios for energy and nutrient intakes of pregnant women in rural malawi show that many days are required to estimate usual intake. j nutr 2002; 132: 131318. 23. palaniappan u, cue ri, payette h, gray-donald k. implications of day-today variability on measurements of usual food and nutrient intakes. j nutr 2003; 133: 232-5. 24. treuth ms, sherwood ne, butte nf, et al. validity and reliability of activity measures in african-american girls for gems. med sci sports exerc 2003; 35: 532-9. 25. trost sg, pate rr, freedson ps, sallis jf, taylor wc. using objective physical activity measures with youth: how many days of monitoring are needed? med sci sports exerc 2000; 32: 426-31. 26. tudor-locke c, burkett l, reis jp, ainsworth be, macera ca, wilson dk. how many days of pedometer monitoring predict weekly physical activity in adults? prev med 2005; 40: 293-8. 27. vincent sd, pangrazi rp. an examination of the activity patterns of elementary school children. pediatr exerc sci 2002; 14: 432-41. 28. welk gj. physical activity assessments for health-related research. champaign, il: human kinetics, 2002. 29. willett wc. nature of variation in the diet. in: macmahon b, ed. nutritional epidemiology: monographs in epidemiology and biostatistics, vol. 15. new york: oxford university press, 1990: 34-51. table vi. intraclass correlation reliability analysis of 4-day accelerometer output indices in rural and urban subjects reliability required number (icc) of days toachieve a reliability of 0.8 variables * 4 days † 1 day rural (n = 21) total counts 0.80 (0.89) 0.50 4.0 average counts 0.84 (0.92) 0.58 3.0 inactivity 0.78 (0.88) 0.47 4.5 moderate-1 0.76 (0.87) 0.45 5.0 moderate 0.79 (0.89) 0.49 4.2 2+vigorous urban (n = 20) total counts 0.79 (0.89) 0.49 4.2 average counts 0.84 (0.92) 0.57 3.1 inactivity 0.64 (0.80) 0.31 9.0 moderate-1 0.27 (0.75) ‡ 0.08 43.8 moderate 0.79 (0.89) 0.49 4.2 2+vigorous *see table i for variable units, icc = intraclass correlation coefficient, † deattenuated iccm appear in parenthesis, icc significant (p<0.002) except ‡ (p=0.1799). pg21-27.indd 27 4/23/08 11:32:10 am original research 36 sajsm vol 24 no. 2 2012 introduction hydration status and its role in the performance of endurance athletes remains a popular topic of debate in sports medicine. newer recommendations, including the 2007 american college of sports medicine position stand on exercise and fluid replacement, warn athletes not to lose >2% body weight during exercise as it may adversely affect performance.1 although the same paper recommends drinking to thirst, the unfounded fear of dehydration and/or heat illness may have prompted athletes in the usa to continue to follow protocols that promote overzealous hydration. however, more recent analysis has shown that the fastest runners (therefore highest performers) abstract objective. prior studies of full-marathon participants have demonstrated a higher incidence of hyponatraemia in runners with completion times of 4 hours or more. our primary aim was to determine if slower pace is associated with increased prevalence of hyponatraemia. secondly, we evaluated the prevalence of hyponatraemia in full-marathoners v. halfmarathoners. methods. this observational, cross-sectional study comprised consenting runners in the 26.2 with donna, the national marathon to finish breast cancer, in jacksonville beach, florida, february 2008. on race day, participants completed a questionnaire, provided finger-stick blood samples, and were weighed both preand post-race. results. a significant negative association was found between pace and post-race sodium level (p<0.001). a negative correlation was found between finishing time and post-race sodium level (p<0.001). the prevalence of post-race hyponatraemia was 4% (4/106) among half-marathoners and 13% (12/89) among full-marathoners (p=0.02). an inverse correlation was found between sodium change and weight change, significant in fullmarathoners (r=-0.55, p<0.001) but not half-marathoners (r=0.23, p=0.042). conclusions. slower race pace and longer finishing times were associated with lower post-race sodium levels. full-marathoners *presented in abstract and poster form at the annual meeting of the american medical society for sports medicine, tampa, florida, 25 29 april 2009. impact of race pace on development of hyponatraemia in fulland half-marathoners* jennifer r maynard, walter c taylor iii, rebecca b mcneil, shane a shapiro, michael m mohseni, tyler f vadeboncoeur, scott m silvers, susan v sumrall, edith a perez, nancy n diehl department of family medicine, mayo clinic, jacksonville, florida jennifer r maynard, md walter c taylor iii, md biostatistics unit, mayo clinic, jacksonville, florida rebecca b mcneil, phd nancy n diehl department of orthopedic surgery, mayo clinic, jacksonville, florida shane a shapiro, md department of emergency medicine surgery, mayo clinic, jacksonville, florida michael m mohseni, md tyler f vadeboncoeur, md scott m silvers, md clinical studies unit, mayo clinic, jacksonville, florida susan v sumrall, rn division of hematology/oncology/cancer center/breast clinic, mayo clinic, jacksonville, florida edith a perez, md corresponding author: j r maynard (maynard.jennifer@mayo.edu). had a significantly higher prevalence of hyponatraemia. the development of hyponatraemia was associated with weight gain. our data indicate that the relationship between post-race sodium concentration and pace differs according to the distance of the event. we can extrapolate from this data that longer race distance with increased availability of fluid stations combined with a slower pace may increase the risk of developing exerciseinduced hyponatraemia. s afr j med 2012;24(2):36-42. sajsm vol 24 no. 2 2012 37 actually are those who lose the most weight in marathons.2 the recognition of the potential dangers of excessive fluid consumption has initiated multiple revisions of these theories. current hydration strategies may be based on individual sweat rate, as monitored by body weight change during exercise, but most importantly should be gauged by thirst to maximise performance.1,3-7 many studies and review papers have documented the risk of overhydration during prolonged endurance events, which may result in hyponatraemia (serum sodium concentration <135 mmol/l).1,5,8-21 the occurrence of hyponatraemia during or up to 24 hours after prolonged physical activity is known as exerciseassociated hyponatraemia (eah).8,12 a large study from noakes et al. reveals that the development of eah occurs from three main factors: overconsumption of fluid during exercise, retention of fluid due to inadequate suppression of antidiuretic hormone (adh), and inactivation of or failure to reactivate internal stores of sodium.22 the confluence of these factors enhances a dilutional state and decreases the serum sodium concentration. signs and symptoms of hyponatraemia include nausea, vomiting, confusion, and headache. as eah progresses, more severe sequelae include seizures, pulmonary and cerebral oedema (hyponatraemic encephalophathy), and possibly death. since its first report in a 26.2 mile (42 km) race in the 1986 pittsburgh marathon, eah has been cited in multiple hospitalisations and at least 5 known deaths of marathon participants.9,18,19 developing science and recognition of eah have linked multiple risk factors, including excessive drinking behaviours, female sex, failure to appropriately suppress adh in the presence of fluid retention, lower body mass index (bmi), slower running pace, non-elite status, and prolonged exercise (>4 hours).1,9,10,12-14,20 our primary aim was to determine if slower pace is associated with increased prevalence of hyponatraemia. a secondary aim was to determine if there is a significant difference in the prevalence of hyponatraemia in halfv. full-marathon participants. this study has the advantage of analysing both preand post-race serum sodium concentrations, as well as the weight of participants before and after exercise to assess the changes incurred during an endurance event. furthermore, we believe the current study is the first to examine the influence of race pace on the prevalence of hyponatraemia with the benefit of data from both halfand full-marathons. with these data, we propose that eah is, in part, a behavioural disease in which athletes are influenced by tenuous information, the availability of fluid stations, and fear of dehydration. methods subjects this observational, cross-sectional study comprised consenting runners who participated in the first 26.2 with donna, the national marathon to finish breast cancer full and half marathons. study design was approved by the institutional review board and used written informed consent and a health insurance portability and accountability act waiver. race participants were approached at random during the health expo held on the 2 days before the race. consenting subjects, at least 18 years of age, were identified by a brightly coloured sticker on their race bib number. race setting the race took place on 17 february 2008 at jacksonville beach, florida. at the start of the race, 08h30, the ambient temperature was 17.8°c (64°f) and humidity 88%. sunny conditions prevailed at the end of the race, with an ambient temperature of 24.4°c (76°f) and 43% humidity. hydration stations were available approximately every mile, with a sports drink (powerade; coca-cola company, atlanta, georgia) offered at every other station. a carbohydrate energy gel (gu energy gel; gu energy labs, berkeley, california) was also available roughly every 3 5 miles after mile marker 10. runners were provided race bags that had various advertisements, race paraphernalia, and local health magazines (www.healthsourcemag.com). no specific instructions regarding hydration were given to race participants. procedures serum sodium concentration was measured the morning of the race and after race completion. height was self-reported by the participants. weight was measured on the same calibrated scale before and after the race. bmi (weight in kilograms divided by the square of height in metres) was calculated before and after the race. runners were instructed to proceed to the runners’ science research tent on completion of the race. they were allowed to consume fluid freely after the race while waiting for their blood to be drawn. venous blood was collected via finger stick and tested on a tabletop analyser (stat profile critical care xpress; nova biomedical, waltham, massachusetts). before the marathon, set-up and implementation studies for linearity and precision were performed by the vendor to meet industry standards. in an effort to maintain impartial interpretation, the results were not reviewed at the time. therefore, no opportunity existed to recommend for or against participation in the race on the basis of pre-race laboratory values. outcome measures the primary outcome measure was the incidence of hyponatraemia (serum sodium concentration [na+] <135 mmol/l). secondary outcome measures included mean changes observed and determination of any statistically significant changes in paired data sets from before and after the race. completion times were recorded by official chip time. race pace, reported in minutes per mile, was calculated by finish time divided by race distance (13.1 or 26.2 miles). sample size considerations the target enrolment was 250 runners, based on an expected volunteer rate of 5% of the 5 000 race participants. after allowing for the loss of up to 20% of records due to inadequate blood samples, we estimated that the prevalence of electrolyte abnormalities would be estimable to within a 3 7% margin of error, depending on the true prevalence and assuming the use of a large-sample approximation to the 95% confidence interval. therefore, the target sample size was expected to provide reasonable precision in the estimation of the preand post-race prevalence of electrolyte abnormalities. analysis continuous variables were summarised using median and range, and categorical variables were summarised using number and percentage. to evaluate the relationship between categorical variables, such as marathon distance (full v. half ) and hyponatraemia status, we used the fisher exact test. the wilcoxon rank sum test was used to compare continuous measures, including race pace and change in serum sodium levels, between fulland half-marathoners. the spearman correlation coefficient was used to assess the correlation between race pace or finishing time and other continuous variables. linear regression was used to explore the relationship between postrace serum sodium level, race pace, and distance. 38 sajsm vol 24 no. 2 2012 ethical considerations restriction of participation based on pre-race laboratory data was not possible because of the blood analysis processing method. pre-race samples were stored on ice and transported to the laboratory at the main campus. laboratory results were not available until after the race. if a symptomatic research participant presented to the race medical tent for treatment, laboratory values were available immediately for use by the treating physician. study investigators were notified and collected a separate blood sample of research participants presenting to the medical tent. results total enrolment of 251 was completed early on the second day of the health expo. although the target enrolment was met without difficulty, 18% (46/251) and 19% (47/251) of enrolled runners did not present for pre-race and post-race finger-stick sampling, respectively. additional records were lost during the process of laboratory analysis. see fig. 1 for data flow illustration. a total of 161 and 195 records remained for pre-race and postrace analyses, respectively. the 39 pre-race records lost because the quantity of blood was insufficient were deemed likely secondary to chilly morning conditions and associated peripheral vasospasm. notably, the number of post-race analyses with insufficient blood quantity was substantially lower at 7 records, presumably because blood samples were easier to obtain in the warmer digits of runners who just completed the race. there were slightly more half-marathon participants than full-marathon participants in both the preand post-race environments. approximately equal numbers of pairs, however, were available for paired analysis (79 half-marathon v. 70 full-marathon pairs). table 1 summarises characteristics of the subjects, according to fullor half-marathon status. there was no statistical difference in age or sex by race type. notably, there was a strong female participation rate of 71% (178/251). the overall race participants were similarly skewed toward a higher female component of 71% (3 950/5 536). table 1 also includes the median changes observed in serum sodium levels between the pre-race and post-race environments. interestingly, more half-marathoners (5/84 (6.0%)) than full-marathoners (3/77 table 1. characteristics of the runners’ science study participants according to fullor half-marathon status* characteristic all participants full-marathoners half-marathoners p-value sex (male) 73/251 (29) 40/125 (32) 33/126 (26) 0.33 age (years) 46 (20 71) 46 (20 70) 45 (24 71) 0.73 finish time (min) 240 (90.6 398.7) 333.7 (194.4 398.7) 166.1 (90.6 358.6) <0.001 pace (min/mile) 12.7 (6.9 27.4) 12.7 (7.4 15.2) 12.7 (6.9 27.4) 0.47 fluid ingested (cups) 16 (1.5 100) 27.5 (2 100) 12.0 (1.5 64.0) <0.001 fluid ingested (cups/min) 0.08 (0.008 0.34) 0.08 (0.008 0.34) 0.08 (0.01 0.33) 0.29 hyponatraemia pre-race 8/161 (5) 3/77 (4) 5/84 (6) 0.72 post-race 16/195 (8) 12/89 (13) 4/106 (4) 0.02 sodium concentration (mmol/l) pre-race 138.7 (105.4 145.8) 139 (133.2 145.8) 138 (105.4 143) 0.16 post-race 140 (125 157) 140 (125 157) 140 (125 151) 0.07 change (post-pre) 2.0 (-11.0 35.6) 0.5 (-11.0 16.0) 2.0 (-6.7 35.6) 0.03 body mass index, median (range), kg/m2 pre-race 24.5 (18.1 42.2) 24.0 (18.2 33.2) 25.0 (18.1 42.2) 0.32 post-race 24.0 (17.7 36.7) 23.6 (17.7 32.6) 24.5 (18.1 36.7) 0.28 change (post-pre) -0.4 (-1.8 0.5) -0.6 (-1.8 0.2) -0.3 (-0.8 0.5) <0.001 weight, median (range), kg pre-race 68.5 (43.1 120.1) 67.9 (43.1 111.1) 68.6 (50.5 120.1) 0.69 post-race 67.1 (41.0 117.5) 67.0 (41.0 108.3) 67.3 (50.1 117.5) 0.60 change (post-pre) -1.1 (-5.7 1.4) -1.5 (-5.7 0.7) -0.8 (-2.7 1.4) <0.001 *continuous variables are reported as median (range), with comparisons between fulland half-marathoners performed using the wilcoxon rank sum test. categorical variables are reported as fraction (percentage), with comparisons between fulland half-marathoners performed using the fisher exact test. fig. 1. data flow in preand post-race settings in accordance with race distance. sajsm vol 24 no. 2 2012 39 (3.9%)) presented with hyponatraemia before the race, with 1 asymptomatic half-marathoner in a state of laboratory-classified severe hyponatraemia (serum sodium 105 mmol/l). however, this difference was not statistically significant (p=0.72). at completion of the race, 3 times as many full-marathoners as half-marathoners were hyponatraemic (12/89 (13.5%) and 4/106 (3.8%), respectively; p=0.02). there was a significant difference in the change in sodium levels between halfand full-marathon runners. the median increase was 2.0 mmol/l for half-marathon runners (range, -6.7 35.6 mmol/l) and 0.5 mmol/l for full-marathon runners (range, -11.0 16.0 mmol/l) (p=0.03, wilcoxon rank sum test). therefore, full-marathon runners experienced a smaller increase in sodium over the course of the race, and significantly more full-marathoners than half-marathoners were hyponatremic after the race (p=0.02). data of the change in weight (kg) and calculated in bmi (kg/m2) among runners indicated that full-marathoners lost significantly more weight during the race (-1.5 kg, -0.6 kg/m2) than halfmarathoners (-0.8 kg, -0.3 kg/m2) (p<0.001, p<0.001). an inverse correlation was found between sodium change and weight change, significant in full-marathoners (spearman correlation r=-0.55, p<0.001) but not half-marathoners (r=-0.23, p=0.042) (fig. 2). see table 2 for full data on hyponatraemic participants according to change in preand post-race sodium concentration (mmol/l) and weight (kg). of the 16 participants who were hyponatraemic post-race, 6 showed an increase in weight. the mean weight change for the hyponatraemic marathoners was -0.07 kg2 (range, -0.9 1.4 kg). the median race pace was 12.7 min/mile (range, 6.9 27.4 min/ mile) for half-marathoners and 12.7 min/mile (range, 7.4 15.2 min/ mile) for full-marathoners. a significant negative association was found between pace and post-race serum [na+] (spearman correlation r=-0.30, p<0.001) (fig. 3). median finishing times for halfand fullmarathoners were 166.1 minutes (range, 90.6 358.6 minutes) and 333.7 minutes (range, 194.4 398.7 minutes), respectively. finishing table 2. reporting preand post-race hyponatraemic participants according to change in sodium concentration (mmol/l) and weight (kg) post-pre-race (*value not obtained) participant distance run pre-race sodium (mmol/l) pre-race hyponatraemia? post-race sodium (mmol/l) post-race hyponatraemia? post pre sodium (mmol/l) pre-race weight (kg) post-race weight (kg) post-pre weight (kg) a half *   134.0 yes * 67.6 67.6 0 b half 141.0 no 134.3 yes -6.7 61.8 63.2 1.4 c half 139.8 no 134.0 yes -5.8 62.7 63.5 0.8 d full 139.0 no 133.0 yes -6.0 60.3 59.4 -0.9 e full 139.0 no 132.0 yes -7.0 64.5 63.8 -0.7 f full 142.0 no 133.0 yes -9.0 91.5 92.0 0.5 g full 136.0 no 130.0 yes -6.0 53.7 53.8 0.1 h full 139.0 no 133.0 yes -6.0 61.5 60.7 -0.8 i full 138.0 no 132.0 yes -6.0 96.5 95.7 -0.8 j full 136.0 no 131.0 yes -5.0 65.9 66.6 0.7 k full 136.1 no 133.0 yes -3.1 49.2 49.0 -0.2 l full 136.0 no 125.0 yes -11.0 54.2 54.6 0.4 m full 138.0 no 133.0 yes -5.0 83.4 82.6 -0.8 n full 141.9 no 134.0 yes -7.9 65.3 65.1 -0.2 o half 130.7 yes 125.0 yes -5.7 75.5 *   p full 134.0 yes 133.0 yes -1.0 84.2 83.6 -0.6 q half 134.0 yes 136.0 no 2.0 75.3 75.3 0 r half 105.4 yes 141.0 no 35.6 54.2 53.1 -1.1 s half 134.7 yes 138.0 no 3.3 76.5 77.2 0.7 t half 1330 yes 135.0 no 2.0 51.5 51.7 0.2 u full 134.0 yes 137.0 no 3.0 64.6 62.9 -1.7 v full 133.2 yes 142.0 no 8.8 50.2 49.7 -0.5 fig. 2. scatterplots of the change in weight (kg) v. change in serum sodium concentration (mmol/l) from postto pre-race in (a) full and (b) half-marathon participants. 40 sajsm vol 24 no. 2 2012 time and post-race sodium level had a significant negative correlation as well (spearman correlation r=-0.28, p=0.001). discussion this study is the first of which we are aware to examine the influence of race pace on the prevalence of hyponatraemia with the benefit of data from both halfand full-marathons. prior studies have shown an increased incidence of hyponatraemia in marathon runners with completion times of more than 4 hours.8,11-13,17,21 no studies found in a review of the literature have looked at actual race pace as a predictor of hyponatraemia. the consensus statement from the second international exercise-associated hyponatraemia consensus development conference 2007 named slower running or performance pace to its list of athlete-related risk factors.12 however, of the 4 articles cited after this statement,8,11,17,21 only almond et al.,8 reporting data from the 2002 boston marathon, commented on pace; the others focused on longer finishing times, generally more than 4 hours. furthermore, almond et al.8 reported only a slower training pace as statistically significant (self-reported by runners on pre-race surveys), but did not calculate pace on the actual day of the race. as eah is nearly non-existent in some countries, such as south africa and new zealand, our data also implicate the perpetuation of fear of dehydration that may continue to promote overconsumption of fluids in the usa. he w et al. 17 rep or ted that longer f inishing times and overconsumption of fluids were the main risk factors associated with the development of hyponatraemia. specifically, they state finishing times of more than 4 hours 20 minutes resulted in the lowest serum sodium levels. although a slower pace can be inferred from this statement, with only a 26.2 mile marathon on which to base their calculations, they were not able to consider distance in relation to change in sodium. current global data have established a prevalence of pre-race hyponatraemia of 0 2%.23 our results demonstrate a pre-race incidence of 6.0% (5/84) for half-marathoners and 3.9% (3/77) for fullmarathoners. higher pre-race incidence of hyponatraemia in the usa raises the question of race participant education. race packets were picked up at the expo 1 2 days prior to the race. among advertisement of sponsors, healthsource magazine (healthsourcemag.com) was included, which may have included advice from local nutritionists. for example, the february 2010 edition contained an article entitled ‘a runner’s diet’. recommendations included: ‘to avoid hitting the wall ... you need to focus on your diet and hydration many days before the event. be sure to increase intake of all fluids and be in a well hydrated state. dehydration adversely affects athletic performance.’24 these messages may have encouraged runners to overhydrate prior to the race. the post-race hyponatraemia prevalence of 13% (12/89) in full-marathoners is in agreement with cohorts evaluated in boston (13%)8 and london (12%).23 in contrast, eah has yet to be reported in a marathon runner in south africa or new zealand, and only occasional cases occur in longer ultramarathon races in south africa (t d noakes, personal communication). our data support the prior finding that a significant inverse relationship exists between total finishing time and serum [na+] (p<0.001). additionally, with the benefit of data from two different distances, we were able to demonstrate the importance of the pacedistance interaction with change in sodium. in fig. 4, a linear regression model of post-race sodium with pace, distance, and the pace-distance interaction as independent variables found a significant interaction between pace and distance (p=0.03). as interactions are difficult to detect, this model indicates that the relationship between post-race sodium and pace indeed differs according to the distance of the run. davis et al.11 reported a retrospective analysis of marathon participants in the 1998 and 1999 suzuki rock ’n’ roll marathon in san diego, california, who presented within 24 hours after the conclusion of the race to a local emergency department. to define unconditioned v. conditioned athletes, the patients were stratified into those finishing in more or less than 4 hours, respectively. none of the hyponatraemic patients finished the race in less than 4 hours, suggesting that unconditioned athletes, or those who run slowly, are at risk for the development of eah. davis et al.11 also discussed the impact of post-race hyperhydration as a major contributor to the development of eah. a possible limitation to our study design is that post-race blood samples were collected directly after the race; therefore, we only measured a minimum occurrence and may have missed the development of eah in those participants who then continued to hydrate aggressively over the next 24 hours. both hew et al.17 and davis et al.11 commented on the inverse relationship of serum sodium to time of presentation. these data were retrospectively reviewed from medical tents and emergency department visits. our study was geared specifically to screen for abnormal serum sodium concentrations that developed during the fig. 3. scatterplots of post-race serum sodium levels v. race pace for full-marathoners and half-marathoners. fig. 4. scatterplot of the inverse relationship between post-race serum sodium level and race pace, with overlaid linear regression lines for fulland half-marathoners (p=0.03). sajsm vol 24 no. 2 2012 41 endurance race. recruited participants were instructed to present to the runners’ science tent before and after the race. consequently, we were unable to report on time of presentation in relation to serum sodium except with regard to race finish time. of note, 360 ml (12 oz) water bottles were available at the finish line, and race participants could drink at will while waiting to have blood drawn. therefore, it is plausible to assume that out of fear of dehydration, those who used the ‘drink as much as possible’ philosophy may have continued to overhydrate after the race and thus have had lower serum sodium levels than if they had hydrated to thirst. our study is in agreement with the consensus statement on eah12 that weight gain during a race is a risk factor for hyponatraemia. of the 16 participants who were hyponatraemic after the race, 6 showed an increase in bmi with a mean change of 0 kg/m2 (range, -0.3 0.5 kg/m2). although more full-marathoners developed hyponatraemia during the race, full-marathoners also lost significantly more weight than their counterparts in the half-marathon. this can be explained by a possible 1 2% decrease in body weight that can occur during a 26.2 mile marathon without a change in total body water. this scenario may lead to a dilutional hyponatraemic state with a net loss or neutral bmi. our results also show that, despite an equal median pace of 12.7 min/mile in both halfand full-marathoners, the latter had a significantly higher prevalence of hyponatraemia (p=0.02). this finding further supports the importance of the performance pacedistance interaction. it may be proposed that a difference between the halfand full-marathon race courses is the number of hydration stations. along our race course, the availability of hydration stations at each mile marker essentially doubled in the fullv. half-marathon. reid et al.25 reported that the limitation of fluid availability with placement of aid stations every 5 km has been shown to be associated with absence of hyponatraemia in a standard marathon. we plan to recommend this arrangement of fluid stations for future races. our study design is not without its limitations. first, selection bias may have occurred with race participants who are more interested in health outcomes associated with endurance racing. second, both data sets were incomplete, limiting paired data set analysis. also, as mentioned above, by collecting blood directly after the race, we lost the ability to detect development of hyponatraemia in the subsequent 24 hours. finally, our study, as well as race participants overall, may have some gender bias toward a higher female component, 71% (178/251) compared with 34.4% female finishers reported by hew et al.17 this may be attributable to the nature of the race to benefit breast cancer research and women living with breast cancer. given that the consensus statement on eah12 names female sex as a risk factor, our study population may have been predisposed to development of eah. finally, we acknowledge the role of certain confounding factors on the data. although our figures clearly suggest that slower pace increases the risk of hyponatraemia, we are unable to determine if this is a true physiological difference due to pace. rather, it may be due to the impact of outside influence of education favouring excessive hydration out of fear of dehydration. or perhaps, when moving at a slower pace, athletes simply have more time to drink at fluid stations. in summary, recommendations on fluid replacement during endurance races continue to evolve. currently at the forefront is drinking ad libitum (according to thirst) with the goal to replace fluid lost as sweat. runners should be encouraged to individualise their hydration strategy on the basis of their particular sweat rates to optimise rather than maximise fluid intake during running.11 it is imperative that the sports medicine community promote this strategy rather than continue to uphold the unsubstantiated fear of dehydration. hyponatraemia occurred significantly more frequently in full-marathoners than in half-marathoners. with the benefit of data from halfand full-marathons, we have illustrated the intricate relationship among race pace, distance, and serum sodium concentration. if eah truly is a behavioural disease based in overconsumption of fluids, then appropriate education and behaviour modification is the key for prevention. acknowledgement. the authors acknowledge all the volunteers and medical personnel who made the national marathon to finish breast cancer a possibility and success in its inaugural year. please note a subsection of these data has been published in sports health march/april 2011 issue. similar graphics and tables were used. mohseni m, silvers s, mcneil b, et al. prevalence of hyponatraemia, renal dysfunction, and other electrolyte abnormalities among runners before and after completing a marathon or half marathon. sports health: a multidisciplinary approach march 2011 3:145-151 [http:// dx.doi.org/10.1177/1941738111400561]. conflicts of interest. none. funding sources. none. references 1. sawka mn, burke lm, eichner er, maughan rj, montain sj, stachenfeld ns. american college of sports medicine. american college of sports medicine position stand: exercise and fluid replacement. med sci sports exerc 2007;39(2):377-390. 2. zouhal h, groussard c, minter g, et al. inverse relationship between percentage body weight change and finishing time in 643 forty-two kilometer marathon runners. br j sports med 2011;45(14):1101-1105. 3. goulet ed. effect of exercise-induced dehydration on time-trial exercise performance: a meta-analysis. br j sports med 2011;45(14):1149-1156. 4. beltrami fg, hew-butler t, noakes td. drinking policies and exercise-associated hyponatraemia: is anyone still promoting overdrinking? br j sports med. 2009;42(10):796-501. epub 2008 apr 9. erratum in: br j sports med apr;43(4):310-311. 5. casa dj, clarkson pm, roberts wo. american college of sports medicine roundtable on hydration and physical activity: consensus statements. curr sports med rep 2005;4(3):115-127. 6. noakes t, immda. fluid replacement during marathon running. clin j sport med 2003;13(5):309-318. 7. cheuvront sn, montain sj, sawka mn. fluid replacement and performance during the marathon. sports med 2007;37(4-5):353-357. 8. almond cs, shin ay, fortescue eb, et al. hyponatremia among runners in the boston marathon. n engl j med 2005;352(15):1550-1556. 9. chorley j, cianca j, divine j. risk factors for exercise-associated hyponatremia in non-elite marathon runners. clin j sport med 2007;17(6):471-477. 10. chorley jn. hyponatraemia: identification and evaluation in the marathon medical area. sports med 2007;37(4-5):451-454. 11. davis dp, videen js, 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of hyponatremia in marathon runners. clin j sport med 2003;13(1):41-47. 18. young m, sciurba f, rinaldo j. delirium and pulmonary edema after completing a marathon. am rev respir dis 1987;136(3):737-739. 19. thompson, j-a, wolff, aj. hyponatremic encephalopathy in a marathon runner. chest 2003;124:313s. 20. ganio ms, casa dj, armstrong le, maresh cm. evidence-based approach to lingering hydration questions. clin sports med 2007;26(1):1-16. 21. noakes td, goodwin n, rayner bl, branken t, taylor rk. water intoxication: a possible complication during endurance exercise. med sci sports exerc 1985;17(3):370-375. 22. noakes td, sharwood k, speedy d, et al. three independent biological mechanisms cause exercise-associated hyponatremia: evidence from 2,135 weighed competitive athletic performances. proc natl acad sci usa 2005;102(51):18550-1855. 23. kipps c, sharm s, tunstall pedoe d. the incidence of exercise-associated hyponatraemia in the london marathon. br j sports med 2011;45(1):14-19. 24. goudreau-santos p. a runner’s diet. healthsource magazine feb 2010:16-19. 25. reid sa, speedy db, thompson jm, et al. study of hematological and biochemical parameters in runners completing a standard marathon. clin j sport med 2004;14(6):34. original research 1 sajsm vol. 29 2017 gait retraining as part of the treatment programme for soldiers with exercise-related leg pain: preliminary clinical experiences and retention w o zimmermann,1,2 md; c w linschoten,3 bsc; a beutler,2 md 1department of training medicine and training physiology, royal dutch army, utrecht, the netherlands 2uniformed services university of the health sciences, bethesda, maryland, usa 3vrije universiteit, amsterdam, the netherlands corresponding author: w o zimmermann (wesselzimmermann@hotmail.com) exercise-related leg pain (erlp) is a common problem in the military. healthy young men can have pain in both legs only weeks after starting a training course, leading to them dropping out of the military. the most common diagnoses in the armed forces of the netherlands are: 1. medial tibial stress syndrome (mtss), 2. chronic exertional compartment syndrome (cecs), or 3. a combination of mtss+cecs.[1] the highest reported incidence of mtss in a military setting was 35% of 124 naval recruits participating in basic military training in australia.[2] an estimation of the incidence of cecs in the military is one in every 2000 us military service members per year.[3] mtss is an overuse injury involving the interface of the tibial bone and soft tissue. the patient with mtss reports pain over the tibia during and after leg loading activities.[4] the definition of cecs is pathologically elevated intracompartmental pressure during exercise, which returns to normal with cessation of exercise.[5] the patient with cecs reports a fullness or cramp like sensation over the involved muscular compartment, often after a specific amount of exertion (time, distance, or intensity).[5] if an intracompartmental pressure measurement (icpm) in the first minute post-exercise is above 35 mm hg and the patient reports pain, the diagnosis cecs is confirmed.[6] if the pressure measurement is below 35 mm hg, a new diagnostic term can be applied: biomechanical overload syndrome (bos).[7] for both mtss and cecs, the exact pathophysiological mechanism is not known.[1] a previous episode of leg pain and the biomechanics of walking and running are a few of many risk factors identified for these conditions in the military.[1] gait retraining, as a treatment for overuse injuries of the lower extremities is presumably widely practiced but until now, was scarcely reported in the literature.[8] gait retraining regimens generally focus on a transition from rear foot to midfoot or forefoot strike, increasing cadence, or altering proximal mechanics.[8] the rationale for gait retraining for overuse injuries of the tibia is the reduction of vertical impact forces [9] and for gait retraining in cecs is the reduction of tibialis anterior activity.[10] gait retraining as a treatment for cecs shows promising results in the first publications on this topic.[11,12] there are no publications on gait retraining as a treatment for mtss, but recent research indicates its positive effects.[8] in the sports medicine department of the armed forces of the netherlands gait retraining as a part of the treatment programme for erlp was introduced in 2013, using sophisticated tools, such as high-speed cameras and an instrumented treadmill, to analyse walking and running biomechanics. the goal of this study is to evaluate the treatment results and to describe preliminary clinical experiences and the retention of gait retraining in a military setting. this study is retrospective in design. methods the study involved an analysis of provided patient care background: gait retraining as part of a treatment programme for exercise-related leg pain (erlp) was introduced in the sports medicine department of the royal netherlands army in 2013. objectives: to describe clinical experiences and retention of gait retraining in a military setting. methods: sixty-one cases from the year 2015 were available for analysis of gait and gait retraining. in 2016, 32 of these patients were available for a follow-up survey, 28 of them also for the follow-up measurement of running biomechanics in running shoes. results: soldiers received an outpatient treatment programme that lasted on average 129 days (sd 76). on average they received 2.4 gait retraining sessions, leading to significant and lasting changes in running biomechanics; in particular, reduction in maximal force (n) and maximal pressure (n/cm2) on the heels at 317 days follow-up (average, sd 108). most soldiers were satisfied with gait retraining. at follow-up, 27 soldiers (84%) contributed some, the majority or all reduction of symptoms to it. seventy percent reported that they had mastered the new running technique within two months. the single assessment numeric evaluation score increased from 55% to 78% for males and from 44% to 75% for females. discussion: this is the first study to report on gait retraining for medial tibial stress syndrome. in future, prospective studies in the military running in shoes and running in boots respectively should be investigated. conclusion: soldiers with exercise-related leg pain (erlp), among them patients with medial tibial stress syndrome, respond well to a treatment programme that included gait retraining. ten months post-gait retraining, their running biomechanics still showed these positive changes from their time of intake. keywords: medial tibial stress syndrome, chronic exertional compartment syndrome, military s afr j sports med 2017;29:1-6. doi: 10.17159/2078-516x/2017/v29i0a1923 mailto:wesselzimmermann@hotmail.com http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1923 original research sajsm vol. 29 2017 2 (patient record analysis), a follow-up survey and measurement of running biomechanics. the inclusion criteria were all soldiers with erlp who received gait retraining as part of their treatment programme in the year 2015 with the following diagnoses: 1. mtss; 2. cecs (icpm > 35 mm hg); 3. bos (icpm < 35 mm hg); 4. mtss+bos; 5. mtss+cecs. all patients were initially seen by a single, senior sports medicine physician (wz), using a detailed intake, diagnostic and treatment protocol for erlp. exclusion criteria were a fasciotomy less than one year ago and previous gait retraining elsewhere. minimal follow-up time was at three months. the following information was retrieved from patient records: patient history, biometrics, pressure measurements of the anterior and deep compartments in the first minute postexercise, diagnosis, kinetics and kinematics of running before gait retraining (t0) and after a single gait retraining session on the same day (t1). the gait retraining intervention in 2015 consisted of four instruction sessions: sessions 1 and 4 were given by a primary care sports medicine physician (wz), and sessions 2 and 3 were given by a physical education instructor. the initial gait retraining session consisted of the following three segments: 1) measurement t0: one minute of running in running shoes, i.e. personal mechanics; 2) running on bare feet, with verbal instructions to change to ball-of-the foot on landing (when applicable) and preferably 180 steps per minute; 3) measurement t1: one minute of running in shoes, new mechanics. the speed of running was 9 km/h for females, 10 km/h for males during all running segments and measurements. the running style (type of strike) was determined based on slow-motion camera evaluation and treadmill vertical force measurement. a heel-striker was defined as a visual heel-striker plus a maximum force on the heels > 400 n. during short moments of rest, all participants were shown a video recording of their original and new running mechanics and the measurements of the instrumented treadmill to learn the reduction in impact forces. instruction sessions 2 and 3 were private gait retraining lessons each lasting 30-60 minutes. all participants received a six-week gait retraining schedule, containing two running sessions a week, to ingrain the new running technique to a continuous running time of 15 minutes. instruction session 4, given by the sports physician, was limited to a brief visual check of the new running mechanics. many patients stayed on for a second sixweek gait retraining schedule, consisting of two-three running sessions a week, to increase running time with the new running technique to 30 minutes at a time. patients were advised not to run more than the time prescribed in the schedules in order to reduce the chance of a recurrence of symptoms. gait retraining was not the only intervention offered in 2015 to patients with erlp. each patient received a personalised programme with a mix of the following interventions: stretching or strengthening of lower extremity musculature, supplementation with vitamin d if below 50 nmol/l, massage of hypertonic musculature, dry needling of trigger points, neuro-prolotherapy with 10% glucose, extra corporeal shockwave therapy of the medial tibial border (four-five sessions), prescription of compression stockings, evaluation of running shoes, evaluation/prescription of shoe inserts, maintaining fitness with a low impact training programme, and radiological imaging. at the end of the treatment programme in the sports medicine department, many patients, particularly those in physically demanding military specialties, were referred to the physical therapist on base for additional training before returning to full duty. from the telephonic follow-up survey in 2016, the following information was obtained primarily with multiple-choice questions: current military status, current erlp status, time and effort required to master the new running technique and any additional medical interventions from other medical professionals in the follow-up period. during the follow-up measurement of running biomechanics (t2) the treadmill (h/p/cosmos sports & medical, nussdorf, germany), the software (zebris medical, isny, germany) and running speed applied were identical to the initial measurements (t0 and t1). the treadmill is serviced yearly. the zebris software allowed for immediate feedback on running biomechanics in three zones of the foot: rearfoot, midfoot and forefoot. in this study, the single assessment numeric evaluation (sane) was used as a subjective score for taxability of the legs on a 0-100 scale, with 100 being normal.[13] the sane score was recorded at intake (sane in), at the completion of the sports medicine treatment programme (sane out) and at follow-up (sane follow-up). all statistical tests were performed using spss version 24.0. the level of significance was set at p < 0.05. data gathered included counts, means and standard deviations for continuous variables and counts and frequencies for categorical variables. a shapiro-wilk test was performed to test for normality of the data. if normality was assumed, independent sample t-tests and paired t-tests were conducted; if not, non-parametric testing was performed (wilcoxon signed ranks test). the study was announced to the medical ethics board, brabant, the netherlands and approved under number nw2016-41. results in total, 61 cases with erlp from 2015 were available for record analysis, 48 males and 13 females. table 1 shows relevant characteristics of these soldiers. the most common diagnoses were mtss+cecs (20 males and seven females) and mtss (15 males and five females). the average duration of the treatment programme was 119 days for men (sd = 63) and 176 days for women (sd = 104). the average sane score of patients improved during this time from 54.6 to 78.4 for males and from 44.6 to 75.3 for females. at intake, 52 soldiers were classified as heel-strikers (85%). at recall in 2016, 32 patients were available for the follow-up survey (53%) (see figure 1). the average follow-up time was 298 days for men (sd = 105.2) and 357 days for women (sd = 82.0), the average follow-up sane score was 73.3 for males and 84.5 for females. in addition, 28 of these 32 patients were available to return to the sports medicine department for original research 3 sajsm vol. 29 2017 follow-up treadmill measurements (46%). statistically, the soldiers not available for follow-up were no different to the soldiers that were available on the factors presented in table 1. reasons for not participating in the follow-up were: no contact possible (17 cases), no time to participate (eight cases) and follow-up time < three months (four cases). table 2 shows selected measurements of the running technique in running shoes at t0, t1 and t2. comparison of measurements at t0 and t1 shows that a single session of gait retraining leads to statistically significant changes in most parameters of running measured. the changes in stride length and cadence are relatively small, the changes in force (n) and pressure (n/cm2) on the heels are relatively large. comparison of measurements at t0 and t2 shows that participants have remained statistically different in most aspects of the running technique measured. for females, the changes in stride length and cadence were no longer statistically different, but force (n) and pressure (n/cm2) on the heels remain significantly reduced at t2 for both males and females. comparison of measurements at t1 and t2 shows that males have lost a significant part of their initial reduction of force (n) and pressure (n/cm2) on the heels. at follow–up, seven soldiers were classified as heelstrikers (25%). tables 3a and 3b show information from the follow-up survey. on average, both males and females received 2.4 gait retraining sessions. the number of gait retraining sessions was called ‘adequate‘ by 59% of the males and 70% of the females, while the others would have preferred one or two more sessions (table 3a). seven patients received only one session (not presented in table 3a). most soldiers were positive about gait retraining. at follow–up, 27 soldiers (84%) contributed some, the majority or all reduction of symptoms to it. mastering the new running technique was reported to be easy or very easy by 12 soldiers (43%) and 19 soldiers (70%) reported that they had mastered the new running technique within two months (table 3b). after completing the treatment programme in the sports medicine department, 14 soldiers (44%) received additional training by a physical therapist and two had surgical treatment (fasciotomy). table 4 shows treatment duration, follow-up time and sane scores in chronological order per diagnostic category. in some table 1. characteristics of all cases analysed (n = 61) and follow-up participants (n = 32) all gait retraining cases follow-up participants male (n = 48) female (n = 13) male (n = 22) female (n = 10) age (years) 25 ± 5 24 ± 5 25 ± 5 24 ± 6 stature (m) 1.82 ± 0.1 1.70 ± 0.1 1.85 ± 0.1 1.7 ± 0.1 weight (kg) 86.9 ± 11.0 70.4 ± 8.0 91.3 ± 9.6 68.1 ± 6.8 bmi 26.3 ± 2.5 24.5 ± 2.8 26.7 ±2.6 23.6 ± 2.2 duration of complaints (months) 12.5 ± 12.3 20.4 ± 32.4 14.0 ± 14.2 18.1 ± 36.1 re-injury 17 (35%) 6 (46%) 6 (27%) 4 (40%) heel striker 42 (88%) 10 (77%) 19 (86%) 9 (90%) navicular drop r (cm) 0.83 ± 0.26 0.77 ± 0.36 0.85 ± 0.29 0.77 ± 0.40 navicular drop l (cm) 0.80 ± 0.31 0.70 ± 0.34 0.80 ± 0.38 0.70 ± 0.39 diagnosis mtss 15 (31%) 5 (39%) 7 (32%) 5 (50%) diagnosis cecs 4 (8%) 1 (8%) 1 (5%) 1 (10%) diagnosis bos 6 (12%) 0 (0%) 3 (14%) 0 (0%) diagnosis mtss + bos 3 (6%) 0 (0%) 2 (9%) 0 (0%) diagnosis mtss + cecs 20 (42%) 7 (54%) 9 (41%) 4 (40%) sane in (%) (mn=47 fm=13) 55 ± 19 45 ± 22 53 ± 16 42 ± 21 duration of treatment (days) 119± 63 176 ± 104 132± 65 136 ± 50 sane out (%)(mn=32 fm=10) 78 ± 19 75 ± 20 82 ± 13 82± 12 moment of follow-up (days) 298 ± 105 357 ± 82 sane follow-up (%) 73 ± 22 85 ± 14 data are expressed as either mean ± sd or as a count (frequency of total). bmi, body mass index; mtss, medial tibial stress syndrome; cecs, chronic exertional compartment syndrome; bos, biomechanical overload syndrome; single assessment numeric evaluation (sane); sane in, sane intake; sane out, completion of the programme fig. 1. study proceedings original research sajsm vol. 29 2017 4 diagnostic categories, already small at intake, only a few participants could be evaluated at follow-up, therefore no further statistical calculations were performed on the data in table 4. after 129 days of outpatient treatment and 317 days of follow-up, military erlp patients reported an average sane score of 77%. patients in the mtss group had the highest average sane out scores. patients in the cecs group had the lowest average sane out and sane follow-up scores. discussion gait retraining as a treatment for overuse injuries of the lower extremities is presumably widely practiced, but scarcely reported in the literature. this study is a retrospective evaluation of gait retraining offered in 2015 to 61 soldiers with erlp. of these soldiers 32 were available for a follow-up survey and of these, 28 for a follow-up p measurement of running technique at 317 days (sd = 108). the soldiers not available for follow-up were statistically similar to those who were available. to the best of these authors’ knowledge, this is the first study to describe the results of gait retraining for mtss patients. at first measurement 85% of soldiers with erlp were identified as heel-strikers. this is similar to previous findings on strike patterns among soldiers.[14] one gait retraining session offered by a primary care sports medicine physician changing strike pattern and introducing relatively small changes in stride length and cadence can produce a statistically significant change in most parameters of running, but, in particular, in maximal force (n) and maximal pressure (n/cm2) on the heels. this reconfirms that the biomechanical parameters of running table 2. kinetics and kinematics of running in sports shoes at t0 (intake), t1 (lesson 1) and t2 (follow-up) male t0 (n=48) t1 (n=43) t2 (n=19) t1 vs t0 t2 vs t0 t2 vs t1 mean sd mean sd mean sd % % % stride length (cm) 204 12.4 192 8.3 197 13.4 94* 97* 103 cadence (steps/min) 161 8.9 173 7.3 169 11.5 107* 105* 98 max force heel (n) 614 159.3 211 89.5 348 227.1 34* 57* 165* max force midfoot (n) 749 136.2 798 150.3 839 158.4 106* 112* 105 max force forefoot (n) 1023 197.3 887 151.9 956 217.4 87* 94* 108 max pressure heel (n/cm2) 28 7.3 17 5.1 21 8.1 60* 73* 120* max pressure midfoot (n/cm2) 26 7.9 26 4.3 28 3.5 98* 107 109 max pressure forefoot (n/cm2) 26 5.1 28 5.3 31 4.8 106* 119* 112 female t0 (n=13) t1 (n=12) t2 (n=9) t1 vs t0 t2 vs t0 t2 vs t1 mean sd mean sd mean sd % % % stride length (cm) 189 15.8 178 12.5 182 8.0 95* 97 102 cadence (steps/min) 160 6.6 168 8.5 166 7.9 105* 104 99 max force heel (n) 489 164.1 167 140.3 175 104.5 34* 36* 105 max force midfoot (n) 576 124.0 693 207.3 663 111.1 120* 115* 96 max force forefoot (n) 820 107.8 694 144.3 806 150.3 85* 98 116 max pressure heel (n/cm2) 26 7.6 15 7.5 14 6.9 58* 54* 93 max pressure midfoot (n/cm2) 26 6.2 27 7.0 28 5.5 102 107 105 max pressure forefoot (n/cm2) 27 5.9 29 5.0 32 3.8 105 118* 112 * significant at p <0,05 table 3a. information from the follow-up survey male n = 22 female n = 10 currently in military service 22 (100%) 9 (90%) replaced in a lighter specialty 3 (14%) 1 (10%) number of gait retaining sessions received 2.4 ± 1.3 2.4 ± 0.8 was this number adequate (yes) 13 (59%) 7 (70%) number of gait retraining sessions preferred 3.4 ± 1.5 2.8 ± 1.2 data are expressed as either mean ± sd or as a count (frequency % of total). original research 5 sajsm vol. 29 2017 can be readily modified with deliberate instruction.[15] measurement at follow-up shows that participants lose a percentage of the changes that were made after the first gait retraining session, but a statistically significant reduction in force and pressure at the heels remains (table 2). at 317 days follow-up 25% of the soldiers were still heel-strikers, indicating perhaps an individual variation in susceptibility to gait retraining. at follow-up the average sane score of erlp patients was 77% (table 4). this shows that many soldiers with erlp experience persistent difficulty with running even after a comprehensive conservative sports medicine outpatient treatment programme for 317 days. in the dutch armed forces, as in the british and american forces, erlp is a major cause of decreased readiness to continue with training.[1] continued effort is warranted in both the primary prevention and treatment of these injuries. in previous studies, positive results were reported with gait retraining in the treatment of soldiers diagnosed with cecs.[11,12] in this study patients with mtss also responded well to a treatment programme, which included gait retraining. this is a novel finding and should encourage healthcare workers to introduce gait retraining as part of the treatment of mtss patients. in controlled study settings gait retraining has been executed with eight instruction sessions in two weeks, or 18 sessions in six weeks.[9,11,12] short-term clinical success with only three gait retraining sessions has been reported.[10] this retrospective analysis shows that some patients had a high sane follow-up score with as little as a single gait retraining session; however, most soldiers would have preferred three to four sessions. on average, patients received 2.4 gait retraining sessions, where four sessions were intended. stimulating attendance at all four gait retraining sessions more stringently may improve treatment results in the authors’ department and may reduce the number of treatments sought after completing their programme. this study reports on gait retraining of soldiers running in running shoes. many patients in this study indicated that their symptoms induced by running in running shoes were enhanced when running in military boots. in the authors’ lab, effects of similar magnitude have been observed with gait retraining of running in boots (meindl, germany). no studies are available on gait retraining of running in military boots. this study has several of the inherent limitations of a retrospective analysis: incomplete patient records, different follow-up times per case analysed, patients unavailable for follow-up, and no control group. in addition, patients with different diagnoses in the erlp group were included and they received different treatment programmes of different duration. it is important to recognise that the benefits of the treatment provided cannot be attributed to gait retraining alone. however, accepting these major limitations, the strength of this study is that it presents new and practical information on gait retraining and its retention as part of a treatment programme for soldiers with erlp. the follow up period, 317 days, is long compared to most published studies [15] and contact with 53% of the patients, on average after 10 months, is a good recall result in a military setting. it is also an instructive precursor for a prospective study on gait retraining of the same patient population. in future table 3b. patient evaluation of gait retraining at follow-up male female time required to master new running technique n = 19 n = 8 1 month 11 5 2 months 2 1 3 months 4 1 > 3 months 2 1 effort required to master new running technique n = 20 n = 8 very little, it is very easy 2 0 little, it is easy 5 5 intermediate 7 2 a lot, it is hard 6 1 symptom reduction attributed to new running technique n = 22 n = 10 no symptom reduction 3 2 some symptom reduction 8 3 the majority of symptom reduction 5 2 complete symptom reduction 6 3 table 4. treatment periods and subjective evaluation per diagnostic category sane in (%) duration of treatment (days) sane out (%) follow-up time (days) sane follow-up (%) table 4. treatment periods and subjective evaluation per diagnostic category sane in (%) duration of treatment (days) sane out (%) follow-up time (days) sane follow-up (%) mean sd n mean sd n mean sd n mean sd n mean sd n mtss 56 18 20 114 43 20 84* 14 15 340 98 12 78*+ 19 12 cecs 54 21 5 122 67 4 63 31 3 345 6 2 50 28 2 bos 56 17 5 89 48 5 70* 17 3 287 80 3 80 13 3 mtss + bos 60 10 3 208 135 2 83 4 2 347 263 2 75 35 2 mtss + cecs 48 22 27 143 92 27 74* 21 18 294 113 13 80*+ 20 13 all syndromes 52 20 60 129 76 58 77* 19 41 317 108 32 77*+ 20 32 * significant change from sane in at p <0,05; + no significant change from sane out at p>0,3 mtss, medial tibial stress syndrome; cecs, chronic exertional compartment syndrome; bos, biomechanical overload syndrome; single assessment numeric evaluation (sane); sane in, sane intake; sane out, completion of the programme; original research sajsm vol. 29 2017 6 studies, it is advisable to measure running mechanics both in running shoes and in military boots at intake and at the completion of the gait retraining intervention. follow-up measurements could be planned at six and 12 months respectively. conclusion this study is a retrospective analysis of patient care, with a follow-up, among dutch soldiers with erlp. the erlp patients received on average 2.4 gait retraining sessions. significant and lasting changes were achieved in running biomechanics, in particular in maximal force (n) and maximal pressure (n/cm2) on the heels at 317 days followup. soldiers with erlp were satisfied with gait retraining as part of their treatment programme. patients with medial tibial stress syndrome responded well to the treatment programme that included gait retraining as reflected by the increase of their sane scores. it is suggested that four gait retraining instruction sessions, spread over two-three months, with homework exercises, can be sufficient to produce positive clinical results. in future, prospective studies on gait retraining in the military, both running in running shoes and running in boots should be investigated, because both shod conditions are relevant for the military patient. conflict of interest: the authors have no conflict of interest to declare. contributions by the authors: guarantor of this article is wz. all patients were initially seen by wz. the follow-up has been executed by cl. statistics by cl. text concept by wz, text contributions by cl and ab. all authors agree with the final version of this article. references 1. zimmermann wo, helmhout ph, beutler a. prevention and treatment of exercise related leg pain in young soldiers; a review of the literature and current practice in the dutch armed forces. j r army med corps 2017;163:94-103.; [doi:10.1136/jramc-2016-000635] [pmid:27451420] 2. yates b, white s. the incidence and risk factors in the development of mtss among naval recruits. am j sports med 2004;32(3):772-780. [doi:10.1177/0095399703258776] [pmid:15090396]; 3. waterman br, liu j, newcomb r, et al. risk factors for cecs in a physically active military population. am j sports med 2013;41(11):2545-2549. [doi:10.1177/0363546513497922] [pmid:23911700] 4. moen mh, tol jl, weir a, et al. medial tibial stress syndrome: a critical review. sports med 2009;39(7):523-546. [doi:10.2165/00007256-200939070-00002] [pmid:19530750] 5. rajasekaran s, hall m. nonoperative management of chronic exertional compartment syndrome: a systematic review. curr sports med rep 2016;15(3):191-198. [doi:10.1249/jsr.0000000000000261] [pmid:27172084 6. aweid o, del buono a, malliaras p, et al. systematic review and recommendations for intracompartimental pressure monitoring in diagnosing chronic exertional compartment syndrome of the leg. clin j sport med 2012;22(4):356-370. [doi:10.1097/jsm.0b013e3182580e1d] [pmid:22627653] 7. franklyn-miller a, roberts a, hulse d, et al. biomechanical overload syndrome: defining a new diagnosis. br j sports med 2014;48(6):415-416. [doi:10.1136/bjsports-2012-091241] [pmid:22983122] 8. barton cj, bonanno dr, carr j, et al. running retraining to treat lower limb injuries: a mixed-methods study of current evidence synthesised with expert opinion. br j sports med 2016;50(9):513-526. [doi:10.1136/bjsports-2015-095278] [pmid:26884223] 9. crowell hp, davis i. gait retraining to reduce lower extremity loading in runners. clin biomech (bristol, avon) 2011;26(1):7883. [doi:10.1016/j.clinbiomech.2010.09.003] [pmid:20888675] 10. landreneau ll, watts k, heitzman je, et al. lower limb muscle activity during forefoot and rearfoot strike running techniques. int j sports phys ther 2014;9(7),:888-897. [pmid:25540704] [pmcid:pmc4275193] 11. diebal ar, gregory r, alitz c,et al. forefoot running improves pain and disability associated with chronic exertional compartment syndrome. am j sports med 2012;40(5):1060-1067. [doi:10.1177/0363546512439182] [pmid:22427621] 12. helmhout ph, diebal ar, van der kaaden l, et al. the effectiveness of a 6-week intervention program aimed at modifying running style in patients with chronic exertional compartment syndrome. orthop j sports med 2015;3(3): 11772325967115575691. [doi:10.1177/2325967115575691] [pmid:26665032] 13. williams gn, gangel tj, arciero ra, et al. comparison of the single assessment evaluation method and two shoulder rating scales: outcomes measures after shoulder surgery. am j sports med 1999;27(2):214-221. [doi:10.1177/03635465990270021701] [pmid:10102104] 14. warr bj, fellin re, sauer sg, et al. characterization of footstrike patterns: lack of an association with injuries or performance in soldiers. mil med 2015;180(7):830834.[doi:10.7205/milmed-d-14-00220] [pmid:26126256] 15. napier c, cochrane ck, taunton je, et al. gait modifications to change lower extremity gait biomechanics in runners: a systematic review. br j sports med 2015;49(12):1382-1388. [doi:10.1136/bjsports-2014-094393] [pmid:26105016] sajsm vol 23 no. 3 2011 95 summary hamstring injuries are common in jumping and sprinting athletes. this case series documents acute grade i ii hamstring injuries in two paralympic athletes. these athletes were able to transcend their injuries to compete 4 and 6 days after injury to attain personal best achievements. introduction hamstring muscle injuries are one of the most common injuries sustained by jumping and sprinting athletes, and remain a challenge for both athlete and clinician due to slow healing, persistent symptoms and high rate of recurrence. 1,2 these injuries can usually result in significant consequences on performance due to time loss from training and competition. 3-5 although there is a relative paucity of published literature on musculoskeletal injuries in athletes with disabilities, it is evident that overall injury rates are the same for athletes with and without physical disability. 6 yet, the one group of disabled athletes that may be at higher risk for musculoskeletal injury are the amputees as they often experience muscle imbalances and have biomechanical compensation. 6 athletes with disability who have attained a high level of performance in sport, for example those that represent their country at the paralympic games, have demonstrated an ability to overcome adversity and achieve accomplishment in physical performance adespite physiological challenge. this case series documents the musculoskeletal injury in two paralympic athletes. both athletes provided consent for the publication of their clinical material. case 1 history a 23-year-old acquired single below-knee amputee (t44) sprinter, presented 3 days before competition at the 2008 paralympic games with acute posterior thigh pain (in the amputee leg) during sprint start training. a previous injury to this area had occurred 3 weeks prior to this incident. physical examination and special investigations clinical examination revealed acute tenderness on palpation of the hamstring muscle belly with inability of resisted muscle contraction. mri scanning (figs 1 and 2) revealed a grade i ii (94 x 19mm) acute upon chronic tear of the belly of the semimembranosis muscle. management management included initial immobilisation, cryotherapy, compression and rest with early physiotherapy. non-steroidal anti-inflammatory medication was administered 24 hours after the injury. advice regarding expectations with respect to further participation at the wayne derman (mb chb, phd, facsm, ffims)1 suzanne ferreira (phd)2 kevin subban (mb chb, mmed sc (sports medicine))3 richard de villiers (mb chb, mmed(radd))4 1 mrc/uct research unit for exercise science and sports medicine, university of cape town and ioc research centre for injury prevention and protection of athlete health 2 department of sport science, university of stellenbosch 3 private practice 4 van wageningen & partners radiologists, sports science institute of south africa correspondence to: wayne derman (wayne.derman@uct.ac.za) transcendence of musculoskeletal injury in athletes with disability during major competition case report fig. 1. mri of hamstrings. coronal stir. grade iii muscle tear (measuring 94 mm x 19 mm). note hyperintense signal in the left semimembranosis muscle belly at the musculotendinous junction. 96 sajsm vol 23 no. 3 2011 competition was provided to the athlete, with the option of withdrawal from the competition being considered. three days later the athlete competed in the semifinal heat of the paralympic 100 m (t44) and recorded a qualifying time 12.05 seconds. the following day the athlete completed the final of the 100 m (t44) race, recording a personal best time of 11.68 seconds, narrowly missing out on the bronze medal. case 2 history a 27-year-old congenital single below-elbow amputee (f46) longjumper/sprinter presented 4 days prior to competition at the 2008 paralympic games with acute posterior thigh pain in the takeoff leg during long-jump training. a previous injury to this area had occurred 12 weeks prior to this incident. fig. 2. mri hamstrings. axial stir sequence. grade i ii muscle tear. note hyperintense signal in the left semimembranosis muscle belly at the musculotendinous junction. fig. 4. mri hamstring. axial stir both hamstrings. note feathery pattern in the right semimembranosis muscle at the musculotendinous junction. features compatible with a grade i muscle strain. fig. 5. mri hamstring. sagittal stir sequence. note feathery pattern in the right semimembranosis muscle at the musculotendinous junction. features compatible with a grade i muscle strain. fig. 3. mri hamstring. coronal stir both hamstrings. note feathery pattern in the right semimembranosis muscle at the musculotendinous junction. features compatible with a grade i muscle strain. sajsm vol 23 no. 3 2011 97 physical examination and special investigations clinical examination revealed acute tenderness over palpation of the hamstring muscle belly of the takeoff leg with inability of resisted muscle contraction. mri scanning (figs 3, 4 and 5) revealed a large grade i (110 x 25 mm) acute upon chronic muscle tear with fluid accumulation within the belly of the semimembranosis muscle. management management included initial immobilisation, cryotherapy, compression and rest with early physiotherapy intervention. non-steroidal anti-inflammatory medication was administered 24 hours after the injury. advice to withdraw from the 200 m sprint event (which preceded his main long-jump event) and expectations regarding further participation at the competition was provided to the athlete, with the option of withdrawal from the competition considered. four days later the athlete competed in the heat of the 200 m and 6 days following injury won the silver medal in the t46 long-jump final, recording a personal best distance of 6.64 m. discussion perhaps one of the most difficult aspects of the function of the team physician is the decision regarding ongoing participation following injury. whilst there are many factors that are taken into account including the nature of the injury, risk of worsening or extension of the injury, the nature of the event/competition and the athlete’s and coach’s opinion, are all considered. sometimes the decision to withdraw an athlete is clear, for example if there is threat to life or limb; at other times it is not quite clear, for instance in respect of less severe injury at a ‘career pinnacle’ competition like the paralympic games. review of the literature reveals that in athletes with similar injuries return to sport occurs not before 13 48 days following acute injury. 3-5 indeed, the mean time to return to sport in athletes with muscle tears which are visible on mri scanning is 27 days. 4 the two athletes described in this series competed successfully without analgesia, 4 days and 6 days following injury, achieving personal best times and distances. while the response to injury and subjective experience of pain can vary from person to person, the events described above demonstrate human ability to transcend injury and compete at the highest level and achieve personal best results and in some instances medals. athletes with disability often demonstrate resilience and are accustomed to adversity. 7 indeed, athletes with disability report more sport-related muscle pain compared with their able-bodied counterparts as their training increases and therefore they might be more accustomed to competing with pain. 8 yet factors governing performance following injury in athletes with disability are an underresearched area and therefore not fully understood. it should be stressed that this case series is not intended to promote athlete participation in the presence of injury, and it is recognised that rest, recovery and rehabilitation in the injuries described above should be adhered to as recurrent injury is undesired and not in the best interest of the athlete and their future performances. 9,10 following completion of the paralympic games both athletes were referred for ongoing physiotherapy and rehabilitation in their respective cities and this was completed successfully. both athletes competed in, and achieved medals at, the 2011 ipc track and field world champs in christchurch, new zealand. acknowlegements the authors would like to thank the sa physiotherapy team to the 2008 paralympic games, sascoc and sasapd. references 1. heiderscheit bc, sherry ma, silder a, chumanov es, thelen dg. hamstring strain injuries: recommendations for diagnosis, rehabilitation, and injury prevention. j orthop sports phys ther 2010;40(2):67-81. 2. verrall gm, kalairajah y, slavotinek jp, spriggins aj. assessment of player performance following return to sport after hamstring muscle strain injury. j sci med sport 2006;9(1-2):87-90. 3. slavotinek jp, verrall gm, fon gt. hamstring injury in athletes: using mr imaging measurements to compare extent of muscle injury with amount of time lost from competition. ajr am j roentgenol 2002;179(6):1621-1628. 4. verrall gm, slavotinek jp, barnes pg, fon gt. diagnostic and prognostic value of clinical findings in 83 athletes with posterior thigh injury: comparison of clinical findings with magnetic resonance imaging documentation of hamstring muscle strain. am j sports med 2003;31(6):969-973. 5. askling c, saartok t, thorstensson a. type of acute hamstring strain affects flexibility, strength, and time to return to pre-injury level. brit j sports med 2006;40(1):40-44. 6. willick s, webborn, n. medicine. in: vanlandewijck y, editor. the paralympic athlete. 1st ed: blackwell publishing ltd, 2011:74-88. 7. martin jj, wheeler, g. psychology. in: vanlandewijck y, editor. the paralympic athlete: blackwell publishing ltd, 2011:116-34. 8. bernardi m, castellano, v., ferrara, m.s., sbriccoli, p., sera, f., marchetti, m. muscle pain in athletes with locomotor disability. med sci sports exerc 2003;35:199-206. 9. copland st, tipton js, fields kb. evidence-based treatment of hamstring tears. curr sports med rep 2009;8(6):308-314. 10. mendiguchia j, brughelli m. a return-to-sport algorithm for acute hamstring injuries. phys ther sport 2011;12(1):2-14. original research sajsm vol. 27 no. 3 2015 87 background. although literature on sports psychology outlines parental influence in various areas, research has not focused on its potential in the framework of doping. objective. to assess whether parents’ knowledge about doping effects, and their behaviour and beliefs might act as a protecting factor for austrian junior (14 18 years) elite athletes’ doping susceptibility (ds). methods. questionnaires were distributed to 1 818 student athletes and their parents. as well as collecting sociodemographic data, information about current sports activity levels and the former sports careers of parents, the following categories were included: (i) knowledge about effects of doping; (ii) parental behaviour; (iii) parental beliefs about athletes’ skills to become a professional athlete; and (iv) ds. results. in total 527 data sets were entered for analysis. current state of knowledge was significantly different between mothers (0.72 (0.2)) and fathers (0.76 (0.2)) (p=0.003). next to situational variables, only fathers’ behaviour, which was moderated by fathers’ beliefs, was a significant predictor of athletes’ ds. conclusion. fathers have the potential of acting as a protective factor for ds in athletes, but only if their level of belief is moderate. doping prevention strategies should include parents, but need to be careful on the role they are planning to fulfil, with an emphasis on soft skills (e.g. communication). future research might include variables from sports psychology such as motivational climate, goal orientation and belief in success as possible mediators of the influence of parents on their adolescent children in the sport setting. s afr j sports med 2015;27(3):87-91. doi:10.7196/sajsm.8094 role of parents as a protective factor against adolescent athletes’ doping susceptibility c blank,1 phd; v leichtfried,1 phd; d müller,2 phd; w schobersberger,1 md 1 institute for sports medicine, alpine medicine & health tourism, university for health sciences, medical informatics and technology, hall; and tirol kliniken, innsbruck, austria 2 national anti-doping agency, vienna, austria corresponding author: c blank (cornelia.blank@umit.at) doping in sport, as defined by the world anti-doping code,[1] is generally considered as unhealthy, unethical, unsportsmanlike, and ‘poor’ behaviour in sport. yet the abuse of performance-enhancing substances (pes) is not only an issue in adult elite sport but has also been reported in adolescent athletes.[2] in the last decade doping prevention (including in adolescent athletes) has mostly been athlete-centred and education focused.[3] increasingly, research has been developed which focuses on athletes’ support personnel such as trainers[4] and physicians.[5] research in sports psychology supports the notion that variables in younger athletes (e.g. motivational climate, self-efficacy beliefs, goal orientation) might also be affected by their personal network including parents.[6,7] lavoi and babkes stellino[6] found that the sports climate created by the parents, in terms of ‘learning climate’, ‘worry conducive climate’ and ‘success without effort climate’ significantly predicted athletes’ good and poor behaviour in sport. generally, several researchers have identified parents as ‘sport socialisation agents’,[8,9] and they have the potential to act as role-models. different forms of parents’ influence on their children’s sport development have been analysed (e.g. expectations, values, encouragement, support and beliefs about their children’s ability).[8] in addition, white et al.[7] report that effective parental beliefs and how their children perceive them have an influence on their development. it seems that perceived parental beliefs are related to goal orientation and personal beliefs in a coherent fashion.[7] in the non-sport context parents are also increasingly recognised as part of prevention programmes (e.g. sexually transmitted diseases). [10] the authors found that greater amounts of parent-child sexual communication are associated with fewer sexual risk behaviours, more condom use and greater intention of safer sex behaviour in the future. evidently, parents are involved in their children’s development of general beliefs, their own abilities and a sports-related value system, as well as being able to promote their health. we therefore hypothesise that parents might also be a protective factor in their adolescent children’s doping susceptibility (ds). even though previous research suggests including parents within educative prevention approaches, barely any research has evaluated the associations between parents and adolescents in terms of doping prevention. to our knowledge, only one study by dodge[11] evaluated effects of parental communication in terms of doping prevention, finding that parents who are not perceived as competent might fear an increase in anabolic steroid use if they discuss the topic with their children. however, there are many questions still outstanding on parents’ involvement. 88 sajsm vol. 27 no. 3 2015 the objective of this study was therefore to examine whether parents’ knowledge, communication behaviour and beliefs on whether their child has the skills to become a professional athlete are associated with their ds. the results might provide an insight into whether parents have the potential to act as a protective factor in athletes’ ds, which could possibly lead to new ideas for future preventive measures. methods ethical considerations prior to the collection of data this cross-sectional survey study was reviewed for protection of human subjects and approved by the research ethics committees of the medical universities of innsbruck, graz, vienna and lower austria (sankt pölten) (innsbruck: an3854, 284/4.1., graz: 23-206 ex 10/11, vienna: 1096/2010, sankt pölten: gs4-ek-4/121-2011). the study is part of a research project evaluating knowledge and attitudes of austrian junior elite athletes, their parents and trainers. all study participants were informed about the study goals and provided written informed consent. based on austrian law (§21 allgemeines bürgerliches gesetzbuch), adolescents aged 14 years and above are politically mature minors who were, in this specific situation, allowed to sign the written informed consent form on their own. the written consent forms from all participants were detached from the survey prior to analysis and kept in separate storage. study design in total 12 of 27 recognised elite sport schools in austria (selfrecruited) agreed to participate in the survey. in addition two training centres were included, based on personal invitation to take part in the study, as the best tyrolean soccer and american football athletes matching the age criteria are training at these institutions. survey data were collected over a period of one year, between april, 2010 and april 2011, by distributing questionnaires to austrian junior athletes aged between 14 and 19 years during class, these being directly collected by a member of the study team. parents of these athletes also received a questionnaire and were asked to complete and return the forms either to the study site by the athlete and/or by mail using a stamped return envelope with the cost covered by the study budget. to ensure anonymity, data collection was performed with randomly encoded case report forms. questionnaire structure a self-report questionnaire was developed based on previous published questionnaires used to evaluate doping knowledge[12] and ds among athletes,[13] and adapted for the parents in terms of wording. subsequently the questionnaire was pretested on a sample of 20 athletes and their parents, and adapted based on the responses to the pre-test to avoid technical errors and misunderstandings. as this study is part of a major research project, only those questions that refer to the current article’s research hypotheses will be included in analyses. as well as sociodemographic data, situational information on amount of sport per week, kind of sport practised and previous pes offers were included, as they were shown to be associated with athletes’ ds[14] in previous studies. ‘kind of sport’ was grouped into high-risk and low-risk sports. ‘high-risk’ sports included at least one of the following (athletes could indicate more than one sport): running, swimming, body-building, cross-country skiing, biathlon, biking, athletics and triathlon. in addition, the constructs outlined below were operationalised. knowledge about effects of doping substances this section included 11 items with respect to possible effects of taking anabolic steroids, including side-effects affecting health (e.g. ‘the use of anabolic steroids leads to an increase in muscle mass’, true-false format) as used in a similar format in previous research.[12] for data analysis a total score was computed. a score of 1 was achieved when all questions were answered correctly (100% knowledge), whereas a score of 0 indicated no correct answer at all (0% knowledge). parental behaviour this construct included four items with respect to parental communication. one item questioned whether doping is a topic which is discussed by the parents with the physicians of their adolescent child (e.g. ‘do you discuss the issue “doping” with your child’s physician?’) and three items questioned whether general, physical and psychological problems are discussed with (i) the trainer of their adolescent child, (ii) the physician of their adolescent child, and (iii) their adolescent child (binominal response scale yes/no) (cronbach’s alpha = 0.64). for analysis a total mean construct score was computed (0 = no proactive communication, 4 = proactive communication). parental beliefs this construct included three items with regard to whether parents believe their child has the skills to become a professional athlete and is mentally and physically strong enough to win (‘do you believe your child is mentally/physically strong enough to become a professional athlete?’, ‘do you believe your child has the skills it takes to become a professional athlete?’, using a five-point likert-type rating scale from ‘very unsure’ to ‘very sure’). the three items were combined to form an overall variable called ‘overall belief ’ by adding up a mean construct score (0 = no belief in their child having the skills to become a professional athlete, 12 = full belief in their child having the skills to become a professional athlete) (cronbach’s alpha = 0.8). doping susceptibility this construct was operationalised in presenting the athletes with four hypothetical situations followed by the question as to whether they would be willing to take a prohibited substance within these scenarios (‘your strongest opponent has doped and you know about it. would you take a prohibited substance to increase your chances of winning?’; ‘you have secure information that all your opponents have doped. would you take a prohibited substance?’; ‘if you could earn eur1 million by winning a competition, would you take prohibited substances?’; and ‘if there was no risk of getting caught while doping, would you take prohibited substances?’) (cronbach’s alpha = 0.78). to simplify data interpretation the nominal response scale (‘yes’, ‘no’, ‘do not know’) was aggregated to create binominal data (i.e. yes/no). this practice can be found in previous doping research[15] where reports show that anything other than a ‘definitely no/yes’ response to future doping intentions indicates vulnerability. for data analyses a total mean construct score was computed (0 = unsusceptible for doping, 4 = highly susceptible for doping). sajsm vol. 27 no. 3 2015 89 statistical analysis data were analysed using spss 20.0 (ibm, usa). the literature indicates that adolescent children may not view their mother’s and father’s influences similarly,[6,16] and a previous study on parents’ knowledge of and attitudes to doping found sex differences in doping knowledge,[17] which is why data were analysed separately for mothers and fathers. we built a new variable to differentiate between households with both parents present, and only mother or only father present, as this might have an effect on athletes’ ds. if a difference was found, data were analysed further separately. descriptive statistics were used, including mean (standard deviation (sd)). non-parametric tests were applied since the data were not normally distributed (pk-s>0.05). the mann-whitney u-test was applied to test for differences in mothers’ and fathers’ knowledge about effects of doping substances, behaviour and belief scores. preliminary spearman correlation analyses were used to test the hypothesis of possible associations between parents’ knowledge about effects of doping substances, behaviour and beliefs with athletes’ ds. results are displayed with the corresponding correlation coefficient r and the significance value p. correlation analyses as well as previous literature findings were the basis for setting up a regression model of predicting factors for athletes’ ds. multicollinearity indices (variance inflation factor) (1.02; 1.3) and graphical analyses of the dependent variable were verified and resulted in no severe violations of relevant prerequisites for applying linear multiple regression analyses. the two-sided significance level was defined as p<0.05. results demographic data the survey was distributed to 1 818 athletes, and 1 673 completed questionnaires were returned (response rate 92%). parents returned 883 questionnaires, 409 completed by fathers and 474 by mothers. calculation of a response rate is not possible here, since 87% of the parents had more than one child but filled out the questionnaire only once. only those data sets which at least comprised one parent (mother or father) and his and/or her child were included. in total 527 data sets were entered in the final analysis: 308 included both parents, 79 included only the father, and 140 included only the mother. the mean (sd) age of the mothers, fathers and athletes was 44.8 (4.3) , 47.3 (5.3) and 15.9 (1.4) years, respectively. two-thirds (65.1%) of the athletes were male and 34.5% were female; 0.4% did not indicate gender. for more detailed information on the parent and athlete samples, refer to blank et al.,[14,17] respectively. parents’ knowledge about effects of doping substances, behaviour and beliefs mothers’ knowledge about effects of doping substances scored on average 0.72 (0.2), whereas fathers’ knowledge about effects of table 1. associations between parents’ ke, behaviour and beliefs, and athletes’ ds athletes’ ds mothers’ ke mothers’ behaviour mothers’ beliefs fathers’ ke fathers’ behaviour fathers’ beliefs athletes’ ds r 1.00 –0.10 –0.01 –0.03 –0.07 –0.12* –0.20† p 0.03 0.77 0.53 0.15 0.02 <0.001 mothers’ ke r 1.00 0.11 0.11 0.25 0.08 0.07 p 0.02 0.02 <0.001 0.34 0.22 mothers’ behaviour r 1.00 0.19† 0.03 0.29† 0.17‡ p <0.001 0.54 <0.001 0.002 mothers’ beliefs r 1.00 –0.03 0.14* 0.29† p 0.59 0.012 <0.001 fathers’ ke r 1.00 0.07 0.01 p 0.17 0.88 fathers’ behaviour r 1.00 0.26† p <0.001 fathers’ beliefs r 1.00 ke = knowledge about effects of doping substances. *p<0.05. † p<0.001. ‡ p<0.01. 90 sajsm vol. 27 no. 3 2015 doping substances scored 0.76 (0.2) (p=0.003). parental behaviour and beliefs did not significantly differ between mothers and fathers (behaviourmothers = 2.52 (1.1) v. behaviourfathers = 2.41 (1.2); beliefsmothers = 8.31 (2.6) v. beliefsfathers = 8.6 (2.6)). associations between the variables are outlined in table 1. association with athletes’ ds on average, athletes’ ds score was 1.47 (1.5) (4 = highly susceptible), and it was significantly different in athletes who had received an offer of pes before and those who participated in high-risk sport (dshigh-risk sport = 1.91 (1.5) v. dslow-risk sport = 1.31 (1.4), p<0.01; dspes offer = 2.24 (1.5) v. dsno pes offer = 1.36 (1.4), p<0.001). no differences in gender and no associations with age or the hours of training per week of the athletes were found. athletes’ ds was also independent of the fact of having either both parents or only the mother or the father present. for associations of parental variables with athletes’ ds, refer to table 1. multiple linear regression analysis results of a first multiple linear regression analysis showed none of the parent-related variables to be a significant predictor. whether both parents or a single mother or father were in the household did not alter the results. as interaction effects of fathers’ behaviour and beliefs were assumed, an additional multiple regression analysis entering the prediction term of both was performed. in total the model explained 14.2% of the variance (f=4.1, p<0.001). predictive factors were kind of sport (β=0.25, p=0.001) and fathers’ belief (β =-0.33, p=0.029). a tendency was found for fathers’ behaviour to predict athletes’ ds (β =-0.44, p=0.054). subsequent simple slope analyses to evaluate the interaction effect resulted in a significant negative predictive value for fathers’ behaviour (r=-0.26, p=0.042) only, if fathers’ belief score ranged within the second tertile (8≤ scorebelief <10). in conditions with very low or very high expressions of fathers’ belief, the fathers’ behaviour was no significant predictor for athletes’ ds. discussion the main findings of the current study are that parental factors such as their knowledge about effects of doping substances, behaviour and beliefs explain only little of the variance in athletes’ ds. overall effect sizes are relatively low (between 0.1 and 0.3) and independent of the statistical significance, which might be due to the large sample size. one could therefore question the theoretical relevance. in fact, it seems that mothers in general play only a minor role in influencing athletes’ ds. subsequent regression analysis allows the conclusion that fathers’ behaviour seems to be a protective factor against ds, but is moderated by their beliefs about their adolescent child’s skills in terms of becoming a professional athlete. nevertheless, most of the variance is explained by situational conditions such as kind of sport, and whether both parents are in the household or only the mother or father does not seem to play a role. nevertheless, the last statement needs to be interpreted with caution, as the fact that questionnaires were filled in by only one parent, which provided the basis for these calculations, does not necessarily mean that the other parent is not also present in the household. parental behaviour and beliefs were not significantly different between mothers and fathers, yet scores were very moderate and provide room for improvement. interestingly, behaviour variables showed significant associations, which implies that improving the one parent’s behaviour also improves the other parents’ behaviour. only mothers’ knowledge was positively associated with her behaviour. as observational studies do not allow for cause-effect relationships, one has to be careful not to overinterpret this result. on the one hand, it could be an indicator for the fact that mothers who discuss general and doping-related problems with trainers, physicians and their adolescent child also have an increased knowledge about doping. on the other hand, it could also mean that those who know more tend to communicate more about the issue. this finding would be in accordance with research by blank et al.[4] analysing coaches’ behaviour. overall athletes’ ds was low and comparable with results of previous research.[13] in addition, ds was significantly higher in those athletes who had been offered pes before. as previous research proposed that the beliefs of parents can influence the motivational climate for their children, resulting in poor or good sporting behaviour[6,16] – which is linked to doping intention,[18] we hypothesised associations between parental belief and athletes’ ds. however, on first impression no parental variable had any predictive value for athletes’ ds. only after entering a prediction term of fathers’ beliefs and behaviour were both these variables significant predictors of athletes’ ds, with a much higher effect size. obviously there is an interaction effect between fathers’ beliefs and behaviours, and only fathers’ and not mothers’ beliefs and behaviour seem to play a role in predicting athletes’ ds. earlier research supports this finding, stating that fathers are the most important sport role model for adolescent children. [6,9] mothers’ knowledge, which was associated with athletes’ ds on a bivariate level, was no predicting factor for athletes’ ds on regression analysis. generally the total variance experienced was very low (14.2%). even though fathers’ behaviour, moderated by their beliefs, has some predictive value for athletes’ ds, these outcomes seem to challenge findings from sports psychology, overall indicating a strong parental influence.[6,7,16] this might be explained by the results of chan et al.,[19] who argue that at the age of around 10 years parental influence fades and is replaced by the influence of peers. participants in the current study were between 14 and 19 years old. yet steinberg[20] states that parents generally remain the most influential of all relationships, and shape most of the important decisions confronting their children during adolescence. another explanation could be the different focus of the aforementioned studies, which was on the environmental climates of the athletes, especially in terms of motivation. our findings do not necessarily indicate a strong association between knowledge and ds, which supports previous results that could not find any associations between athletes’ knowledge about effects of doping substances and their doping behaviour and/or susceptibility. [21] nevertheless, in view of the research of dodge,[11] parents should still be included within educational prevention measures. her study shows that parents discussing doping with their children and who are perceived as a non-credible source of information might have reason to fear an increase in anabolic steroid use. hence, in sajsm vol. 27 no. 3 2015 91 the same way athletes’ support personnel should be made aware of their role in influencing competitive climates, goal orientation and beliefs of success of the children, especially during adolescence. given the results of this and previous studies,[6,9] fathers should be a given a special focus. study limitations this study has some limitations that need to be addressed. the questionnaire used in this study is self-reporting, possibly leading to socially desirable reporting. this may result in overor underestimating findings. however, in a previous study by barkoukis et al.[13] effect sizes of socially desirable behaviour were actually rather small. owing to the high multicollinearity of the interaction predictor, results in this regard need to be interpreted with caution, even though variance inflation factor values of the regression analyses indicated good values of fit. lastly, owing to its cross-sectional and observational nature, the study results may not be interpreted causally. correlation analyses only provide information on possible predictors of ds, but further research in the form of case-control studies is needed to define causes that allow for suggestions for future prevention strategies. in this regard social science research on doping is still in its infancy. conclusion the objective of the study was to evaluate associations between parents’ knowledge on effects of doping substances, behaviour and beliefs on athletes’ ds. interestingly, only fathers play a role in acting as a protective factor for athletes’ ds. yet this association interacts with the level of fathers’ beliefs in the skills of their adolescent child to become a professional athlete. overall the hypothesised variables explain only little of the variance in ds, and it can be assumed that parents have more of an effect on athletes’ good and/or poor sport behaviour by affecting their environmental climate, as shown by sports psychology literature. we could also not find any significant influence as to whether both parents live in the same household or not. nevertheless, future studies could integrate this exact question within the questionnaire, as we only hypothesised as to this by analysing whether questionnaires were filled in by both parents or only one of them. doping prevention strategies should include parents, but need to be careful as to the role which they are able to fulfil. informing parents is necessary, as they need to be perceived as credible sources. yet alone this seems insufficient, and the authors support previous claims of increased inclusion of soft skills, e.g. communication skills, in parentfocused prevention measures. nevertheless, the study does not allow for proposing specific preventive measures, as additional research is needed to further determine parents’ role in doping prevention and especially whether the focus should be directed to them or rather to athlete-centred measures, i.e. how to deal with parent-created climates efficiently. as this was, to our knowledge, the first study of this kind, we urge the carrying out of further research on the parent-athlete link in terms of doping prevention. the variance explained in our study leaves some room for further investigation. future research might include variables from sports psychology, such as motivational climate, goal orientation and belief of success, as possible mediators of the influence of parents on their adolescent children in the sports setting. acknowledgments. the authors would like to thank the austrian federal ministry of sport and defence, the government of tyrol (division of sport), as well as the national anti-doping agency, vienna, austria, for their support. references 1. world anti-doping agency. world anti-doping code. montreal: world-antidoping-agency, 2009. 2. laure p, binsinger c. doping prevalence among preadolescent athletes: a 4-year follow-up. br j sports med 2007;41:660-663. [http//dx.doi.org/10.1136/ bjsm.2007.035733] 3. goldberg l, elliot d, mackinnon dp, et al. drug testing athletes to prevent substance abuse: background and pilot study results of the saturn (student athlete testing using random notification) study. j adolesc health 2003;32:16-25. [http://dx.doi. org/10.1016/s1054-139x(02)00444-5] 4. blank c, leichtfried v, fürhapter c, müller d, schobersberger w. doping in sports: west-austrian sport teachers’ and coaches’ knowledge, attitude and behavior. dtsch z sportmed 2014;65(10):16-20. [http//dx.doi.org/ 10.5960/dzsm.2014.133] 5. blank c, müller d, schobersberger w. discrepancy between knowledge and interest of austrian sports physicians with respect to doping and doping prevention in sports. int sports med j 2014;15(2):136-145. 6. lavoi nm, babkes stellino m. the relation between perceived parent-created sport climate and competitive male youth hockey players’ good and poor sport behaviors. j psychol 2008;142(5):471-495. [http//dx.doi.org/ 10.3200/jrlp.142.5.471-496] 7. white sa, kavussanu m, tank km, wingate jm. perceived parental beliefs about the causes of success in sport: relationship to athletes’ achievement goals and personal beliefs. scand j med sci sports 2004;14:57-66. [http//dx.doi.org/10.1111/j.1600-0838.2003.00314.x] 8. brustad rj, babkes ml, smith al. youth in sport: psychological considerations. in: singer rn, hausenblas ha, janelle cm, eds. handbook of research on sport psychology. new york: wiley, 2001:604-635. 9. greendorfer sl. socializing processes and sport behavior. in: horn t, ed. advances in sport psychology. 2nd ed. champaign: human kinetics, 2002:377-401. 10. harris al, sutherland ma, hutchinson mk. parental influences of sexual risk among urban african american adolescent males. j nurs scholarsh 2013;45(2):141-150. [http//dx.doi.org/10.1111/jnu.12016] 11. dodge t. incorporating parents in the anti-doping fight: a test of the viability of a parent-based prevention program. montreal: world anti-doping agency, 2011. 12. wanjek b, rosendahl j, strauss b, gabriel hh. doping, drugs and drug abuse among adolescents in the state of thuringia (germany): prevalence, knowledge and attitudes. int j sports med 2007;28(4):346-353. [http//dx.doi.org/ 10.1055/s-2006-924353] 13. barkoukis v, lazuras l, tsorbatzoudis h. beliefs about the causes of success in sports and susceptibility for doping use in adolescent athletes. j sports sci 2014;32(3):212219. [http//dx.doi.org/10.1080/02640414.2013.819521] 14. blank c, leichtfried v, schaiter r, müller d, schobersberger w. associations between doping knowledge, susceptibility and substance use of austrian junior elite athletes. jacobs j sports med 2014;1(1):1-8. 15. gucciardi df, jalleh g, donovan rj. does social desirability influence the relationship between doping attitudes and doping susceptibility in athletes? psychol sport exerc 2010;11(6):479-486. [http//dx.doi.org/10.1016/j.psychsport.2010.06.002] 16. appleton pr, hall hk, hill ap. examining the influence of the parent-initiated and coach-created motivational climates upon athletes’ perfectionistic cognitions. j sports sci 2011;29(7):661-671. [http//dx.doi.org/10.1080/02640414.2010.551541] 17. blank c, leichtfried v, schaiter r, furhapter c, müller d, schobersberger w. doping in sports: knowledge and attitudes among parents of austrian junior athletes. scand j med sci sports 2015;25(1):1166-1124. [http//dx.doi.org/10.1111/sms.12168] 18. barkoukis v, lazuras l, tsorbatzoudis h, rodafinos a. motivational and social cognitive predictors of doping intentions in elite sports: an integrated approach. scand j med sci sports 2013;23(5):330-340. [http//dx.doi.org/10.1111/sms.12068] 19. chan dk, lonsdale c, fung hh. influences of coaches, parents, and peers on the motivational patterns of child and adolescent athletes. scand j med sci sports 2012;22(4):558-568. [http//dx.doi.org/10.1111/j.1600-0838.2010.01277.x] 20. steinberg l. we know some things: parent-adolescent relationships in retrospect and prospect. j res adolesc 2001;11(1):1-19. [http//dx.doi.org/10.1111/1532-7795.00001] 21. petroczi a. attitude-behavior relationship regarding the use of performance enhancing drugs and/or methods. med sci sports exerc 2003;35(5):1. [http//dx.doi. org/00005768-200305001-01809] pg106-107.indd commentary introduction this paper reviews south africa’s recent performance in the delhi 2010 commonweath games relative to the medal forecasts undertaken for the nation prior to the event. 1 the initial research was a relatively novel concept given that host nations in the olympic games have almost exclusively been the focus of performance predictions. 2-5 moreover, forecasts often tend to be made on the basis of macroeconomic variables such as population and gross domestic product, 2,3 with little attention given to a nation’s traditional sporting prowess. methods the methodology used to make the forecasts for south africa in delhi 2010 is documented in the original research paper. 1 in short, the forecasts were based on different scenarios which took into account south africa’s previous performances in the event since rejoining the commonwealth in 1994. forecasts were constructed on a sport-by-sport basis and overall. post delhi 2010, the actual performance of south african athletes was scrutinised alongside the forecasts. this provided an indication of the accuracy of the predicted performance and practical implications of the research. results table i provides a comparative view of south africa’s performance in the commonwealth games on a sport-by-sport basis and overall relative to the number of gold medals and total medals predicted. the data presented in table i can be categorised into four clusters, as outlined below. cluster 1: performance within the predicted range south africa’s gold medal performance in delhi was within the predicted range for 13 out of the 17 sports and overall. moreover, the forecast was accurate at predicting how many total medals south africa would win in 12 out of the 17 sports. swimming, which was the sport in which south africa won the majority of its medals in delhi, features in this cluster. cluster 2: performance below but proximate to the minimum forecast the number of medals won by south africa was one less than the minimum forecast in two instances in terms of gold medals and for one sport (weightlifting) in terms of total medals. cluster 3: performance below the minimum forecast by at least two medals in athletics, the forecast was for south africa to achieve a minimum of four gold medals whereas the actual number was two. in terms of total medals, performance was at least two medals below the minimum forecast for three sports (athletics, boxing and shooting) and overall. athletics and shooting emerged as the sports in which south africa most underperformed relative to the total medal forecast. cluster 4: performance at least two medals above the maximum forecast the actual performance in lawn bowls exceeded the expected maximum performance by two gold medals. a similar outcome was observed in wrestling in terms of total medals. according to the forecast, south africa would win a gold medal in six sports and a medal of any colour in eleven sports. the matrix in fig. 1 identifies the forecasted performance in the individual sports versus actual medal success in those sports. the top left quadrant of the matrix highlights sports in which south african athletes were not expected to win a medal and did not win a medal. the top right quadrant corresponds to sports in which medal success was not predicted but occurred. looking at the top two quadrants, south africa did not win any medals in the sports where success was not predicted. in other words, the forecast correctly predicted the sports in which south africa would not win a gold medal and any medal. sports that south africa was forecasted to medal in that did and did not materialise appear in the bottom left and bottom right quadrants respectively. the accuracy in predicting sports in which south africa would medal varied between the gold and total medal forecasts. for sports where a gold medal was predicted, the forecast accuracy was 50% (3 out of 6 sports). the corresponding statistic for total medals was 64% (7 out of 11 sports). conclusion attempting to forecast the likely performance of a non-host nation competing away from home in a major multi-nation sports event has review of medal predictions for south africa in the delhi 2010 commonwealth games correspondence: girish m ramchandani sport industry research centre sheffield hallam university a118 collegiate hall collegiate crescent sheffield s10 2bp uk tel: +44 (0) 114 225 5461 e-mail: g.ramchandani@shu.ac.uk girish m ramchandani (msc) darryl j wilson (msc) sport industry research centre, sheffield hallam university, sheffield, uk abstract objectives. this paper reviews south africa’s performance in the delhi 2010 commonwealth games relative to predicted medal success. methods. forecasts based on the nation’s previous success are compared against medals won in delhi. results. actual performance is in line with predicted performance in terms of gold medals but total medals won are below expectations. conclusion. the findings are of potential value to relevant sports authorities and follow up research is proposed. 106 sajsm vol 22 no. 4 2010 sajsm vol 22 no. 4 2010 107 been an interesting experiment. the analysis of the actual performance of south african athletes in delhi has revealed some interesting points in relation to the accuracy of the predictions. the key fi ndings are summarised below: • the gold medal forecast was for south africa to achieve between 12 and 15 gold medals in delhi. they managed to win 12 gold medals, which falls within the predicted range. • the forecast for total medals was 40 43 but south africa won 33. the lower than anticipated success in athletics and shooting explains why their total medal count was below the predicted range. • the forecast was more accurate at identifying those sports in which south africa would not win a gold medal or any medal compared with sports in which it would medal. the fi ndings from the predictive element of the research and subsequent testing have two practical implications. first, the results of this research may be of value to relevant sports authorities in south africa to identify how their athletes fared in delhi 2010 relative to an independent appraisal of anticipated performance. second, the research has provided an indication of the extent to which using a nation’s traditional performance in a sporting competition of international signifi cance to predict future performance with reasonable certainty is viable. further research with a wider sample of nations and/or the same nation over time would help to further validate the fi ndings from this research. references 1. ramchandani g, wilson d. forecasting south africa’s performance at the 2010 commonwealth games. s afr j sports med 2010;22(2):42-43. 2. bernard a, busse m. who wins the olympic games? economic resources and medal totals. review of economics and statistics 2004;6(1):413-417. 3. bian, x. predicting olympic medal counts: the effects of economic development on olympic performance. the park place economist 2005; iii:37-44. 4. clarke sr. home advantage in the olympic games. in: cohen g, lantrey t, eds. proceedings of the fifth australian conference on mathematics and computers in sport. sydney, nsw: university of technology sydney, 2000:43-51. 5. shibli s, bingham j. a forecast of the performance of china in the beijing olympic games 2008 and the underlying performance management issues. managing leisure 2008;13:272-292. table i. south africa’s predicted and actual performance in delhi 2010 gold medals total medals predicted range actual predicted range actual sport min max min max athletics 4 5 2 11 12 5 badminton 0 0 0 0 0 0 boxing 1 1 0 2 3 0 cycling 0 0 0 0 1 0 diving 0 0 0 0 0 0 gymnastics 0 0 0 0 1 1 hockey 0 0 0 0 0 0 lawn bowls 0 1 3 1 3 3 netball 0 0 0 0 0 0 rugby 7s 0 0 0 0 1 1 shooting 0 1 0 4 9 0 squash 0 0 0 0 0 0 swimming 5 7 7 11 17 16 table tennis 0 0 0 0 0 0 weightlifting 0 0 0 1 1 0 wrestling 0 0 0 3 3 5 other* 1 1 0 2 2 2 overall 12 15 12 40 43 33 the predicted range for each sport above is based on the minimum and maximum medal forecast for that sport across the three forecast scenarios. however, the 'overall' predicted range refl ects the combined total medal count across all sports within each individual scenario. for this reason, the minimum and maximum values for each sport may not sum to the respective 'overall' fi gures. shaded values indicate cases where values are outside the predicted range. bold values indicate cases where values are outside +/1 of the predicted range. * other includes archery and tennis for which forecasts were not made independently but derived from the predicted performance in the individually listed sports. 2 0 3 5 0 0 0 5 33 0 8 fig. 1. predicted versus actual medal performance for south africa by sport.                                                   fig. 1. predicted versus actual medal performance for south africa by sport. bjsports-2011-090297.indd editorial bleakley cm, glasgow p, macauley dc, et al. br j sports med (2011). doi:10.1136/bjsports-2011-090297 1 of 2 the acronym price (protection, rest, ice, compression and elevation) has been central to acute soft tissue injury management for many years despite a paucity of highquality, empirical evidence to support the various components or as a collective treatment package. treatment paradigms in sports medicine must be updated based on contemporary research evidence. as a recent example, the widespread use of non-steroidal anti-infl ammatory drugs in acute soft tissue injury management has been challenged, particularly with ligament and muscle injuries. 1 ice compression and elevation (ice) is the basic principle of early treatment. most research has focused on the analgesic effect of icing or the associated skin or intramuscular temperature changes; a recent randomised controlled trial by prins and colleagues, 2 which examined the effectiveness of ice on recovery from acute muscle tear, is the fi rst of its kind. clinical studies into compression are also lacking, and much of its rationale is extrapolated from research relating to deep venous thrombosis prophylaxis and lymphoedema management; there is little clinical research on elevation. 3 protection and rest after injury are supported by interventions that stress shield , unload and/or prevent joint movement for various periods. recent animal models 4 – 6 show that short periods of unloading are required after acute soft tissue injury and that aggressive ambulation or exercise should be avoided. but, rest should be of limited duration and restricted to immediately after trauma. longer periods of unloading are harmful and produce adverse changes to tissue biomechanics 1 health and rehabilitation sciences research institute, university of ulster, jordanstown, newtownabbey, uk 2 sports institute of northern ireland, university of ulster, jordanstown, newtownabbey, uk 3 association of physiotherapists in sports and exercise medicine, london, uk 4 ukcrc centre of excellence for public health (ni), queens university belfast, royal victoria hospital, belfast, uk correspondence to c m bleakley, health and rehabilitation sciences research institute, university of ulster, jordanstown, newtownabbey, county antrim bt370qb, uk; chrisbleakley@hotmail.com price needs updating, should we call the police? c m bleakley, 1,3 p glasgow, 2,3 d c macauley 4 and morphology. progressive mechanical loading is more likely to restore the strength and morphological characteristics of collagenous tissue. 4 5 indeed, early mobilisation with accelerated rehabilitation is effective after acute ankle strain. 7 functional rehabilitation of ankle sprain, which involves early weight-bearing usually with an external support, is superior to cast immobilisation for most types of sprain severity. 8 9 functional rehabilitation aligns well with the principles of mechanotherapy, whereby mechanical loading prompts cellular responses that promote tissue structural change. 10 there are consistent fi ndings from animal models that demonstrate how mechanical loading upregulates mrna expression for key proteins associated with soft tissue healing. 4 – 6 the diffi cult clinical challenge is fi nding the balance between loading and unloading during tissue healing. if tissues are stressed too aggressively after injury, the mechanical insult may cause re-bleeding or further damage. protection of vulnerable tissues therefore remains an important principle. but, too much emphasis creates a default mindset that loading has no place in acute management. rest may be harmful and inhibits recovery. the secret is to fi nd the ‘optimal loading’. optimal loading means replacing rest with a balanced and incremental rehabilitation programme where early activity encourages early recovery. injuries vary so there is no single one size fi ts all strategy or dosage. a loading strategy should refl ect the unique mechanical stresses placed upon the injured tissue during functional activities, which varies across tissue type and anatomical region. for example, a muscle injury to the lower limb has cyclic loading through normal ambulation. the upper limb may require additional cyclic load to be factored into the rehabilitation program in order to maximise mechanical stimulus. police, a new acronym, which represents protection, optimal loading, ice compression and elevation, is not simply a formula but a reminder to clinicians to think differently and seek out new and innovative strategies for safe and effective loading in acute soft tissue injury management. optimal loading is an umbrella term for any mechanotherapy intervention and includes a wide range of manual techniques currently available; indeed the term may include manual techniques such as massage refi ned to maximise the mechano-effect. paradoxically, crutches, braces and supports, traditionally associated with rest, may have a greater role in adjusting and regulating optimal loading in the early stages of rehabilitation. police should make us think more about research into designing rehabilitation strategies that are appropriate to the nature and severity of injury in different sports and activities. if the primary principle of treatment is to restore the histological and mechanical properties of injured soft tissue, optimal loading may indeed be sport specifi c. the challenge is in determining what is ‘optimal’ in terms of the dosage, nature and timing. police is not just an acronym to guide management but a stimulus to a new fi eld of research. it is important that this research includes more rigorous examination of the role of ice in acute injury management. currently, cold-induced analgesia and the assurance and support provided by compression and elevation are enough to retain ice within the acronym. competing interests none. provenance and peer review not commissioned; externally peer reviewed. accepted 3 august 2011 references 1. paoloni ja , milne c , orchard j , et al . nonsteroidal anti-infl ammatory drugs in sports medicine: guidelines for practical but sensible use. br j sports med 2009 ; 43 : 863 – 5 . 2. prins jc , stubbe jh , van meeteren nl , et al . feasibility and preliminary effectiveness of ice therapy in patients with an acute tear in the gastrocnemius muscle: a pilot randomized controlled trial. clin rehabil 2011 ; 25 : 433 – 41 . 3. bleakley cm , glasgow pd , philips p , et al ; for the association of chartered physiotherapists in sports and exercise medicine (acpsm). guidelines on the management of acute soft tissue injury using protection rest ice compression and elevation. london: acpsm, 2011:15–21. 4. bring dk , reno c , renstrom p , et al . joint immobilization reduces the expression of sensory neuropeptide receptors and impairs healing after tendon rupture in a rat model. j orthop res 2009 ; 27 : 274 – 80 . 5. martinez da , vailas ac , vanderby r jr , et al . temporal extracellular matrix adaptations in ligament during wound healing and hindlimb unloading. am j physiol regul integr comp physiol 2007 ; 293 : r1552 – 60 . 6. eliasson p , andersson t , aspenberg p . rat achilles tendon healing: mechanical loading and gene expression. j appl physiol 2009 ; 107 : 399 – 407 . 7. bleakley cm , o’connor sr , tully ma , et al . effect of accelerated rehabilitation on function after ankle sprain: randomised controlled trial. bmj 2010 ; 340 : c1964 . 8. jones mh , amendola as . acute treatment of inversion ankle sprains: immobilization versus bjsm online first, published on september 7, 2011 as 10.1136/bjsports-2011-090297 copyright article author (or their employer) 2011. produced by bmj publishing group ltd under licence. group.bmj.com on january 22, 2016 published by http://bjsm.bmj.com/downloaded from http://bjsm.bmj.com/ http://group.bmj.com editorial bleakley cm, glasgow p, macauley dc, et al. br j sports med (2011). doi:10.1136/bjsports-2011-0902972 of 2 functional treatment. clin orthop relat res 2007 ; 455 : 169 – 72 . 9. kerkhoffs gm , rowe bh , assendelft wj , et al . immobilisation and functional treatment for acute lateral ankle ligament injuries in adults. cochrane database syst rev 2002 ; 3 :cd003762. 10. khan km , scott a . mechanotherapy: how physical therapists’ prescription of exercise promotes tissue repair. br j sports med 2009 ; 43 : 247 – 52 . group.bmj.com on january 22, 2016 published by http://bjsm.bmj.com/downloaded from http://bjsm.bmj.com/ http://group.bmj.com police? price needs updating, should we call the c m bleakley, p glasgow and d c macauley published online september 7, 2011br j sports med http://bjsm.bmj.com/content/early/2011/09/07/bjsports-2011-090297 updated information and services can be found at: these include: references #bibl http://bjsm.bmj.com/content/early/2011/09/07/bjsports-2011-090297 this article cites 8 articles, 6 of which you can access for free at: service email alerting box at the top right corner of the online article. receive free email alerts when new articles cite this article. sign up in the collections topic articles on similar topics can be found in the following collections (84)drugs: musculoskeletal and joint diseases (807)trauma (906)injury (266)editor's choice notes http://group.bmj.com/group/rights-licensing/permissions to request permissions go to: http://journals.bmj.com/cgi/reprintform to order reprints go to: http://group.bmj.com/subscribe/ to subscribe to bmj go to: group.bmj.com on january 22, 2016 published by http://bjsm.bmj.com/downloaded from http://bjsm.bmj.com/content/early/2011/09/07/bjsports-2011-090297 http://bjsm.bmj.com/content/early/2011/09/07/bjsports-2011-090297#bibl http://bjsm.bmj.com/content/early/2011/09/07/bjsports-2011-090297#bibl http://bjsm.bmj.com//cgi/collection/editors_choice http://bjsm.bmj.com//cgi/collection/injury http://bjsm.bmj.com//cgi/collection/trauma http://bjsm.bmj.com//cgi/collection/drugs_musculoskeletal_and_joint_diseases http://group.bmj.com/group/rights-licensing/permissions http://journals.bmj.com/cgi/reprintform http://group.bmj.com/subscribe/ http://bjsm.bmj.com/ http://group.bmj.com original research sajsm vol. 26 no. 1 2014 15 background. the emergence of the pedometer as a useful motivational aid for increasing physical activity (pa) has supported its use in pa interventions. objectives. to examine the feasibility of a 10-week pedometer-based intervention complemented by regular motivational messages, to increase ambulatory pa; and to determine the minimum sample size required for a randomised, controlled trial (rct). methods. participants, sourced by convenience sampling of employees from an academic institution, were randomly assigned to either an intervention group (ig) (n=11) or control group (cg) (n=11), following baseline health measurements and blinded pedometer wear (week 1). participants in the ig subsequently wore an unblinded pedometer (10 weeks) to self-monitor daily steps. individualised messages using pedometer data (ig) and general motivational messages (ig and cg) were provided bi-weekly. blinded pedometer wear (ig and cg) and a feedback questionnaire (ig) were completed at week 12. pedometer data were compared between the ig and cg at week 12. results. participants’ perceptions of the intervention supported the benefit of the pedometer as a useful motivational aid and a reminder to increase steps per day. occupational sitting time and inability to incorporate pa into daily routine emerged as the main barrier to adherence. steps per day increased more in the ig (mean ± standard deviation (sd) 996±1 748) than in the cg (mean±sd 97±750). modest improvements were noted in all clinical measures (ig). conclusion. based on the improvement of 1 000 steps/day (ig), a minimum of 85 participants in the ig and cg, respectively, is required for a future rct (80% power; p<0.05). we recommend a minimum of 150 participants in each group to account for loss to follow-up and to allow for subgroup analyses. s afr j sm 2014;26(1):15-19. doi:10.7196/sajsm.500 steps that count! a feasibility study of a pedometer-based, healthpromotion intervention in an employed, south african population j d pillay,1,2 phd; t l kolbe-alexander,1 phd; k i proper,3 phd; w van mechelen,1,3 phd; e v lambert,1 phd 1 uct/mrc research unit for exercise science and sports medicine, faculty of health sciences, university of cape town, south africa 2 department of basic medical sciences, faculty of health sciences, durban university of technology, south africa  3 department of public and occupational health, emgo institute for health and care research, vu university medical centre, amsterdam, the netherlands corresponding author: j d pillay (pillayjd@dut.ac.za) physical inactivity is a global health concern[1] with complex solutions, as behavioural change is often difficult to achieve and, more importantly, to sustain. [2] small behavioural changes may, however, be more feasible to achieve and maintain.[3] pedometers have been shown to offer a good solution for a low-cost, objective monitoring and behavioural modification tool and practical aid for physical activity (pa) interventions.[4-8] pedometers have therefore gained popularity for use in pa interventions in various settings[9] to facilitate behavioural change. providing individualised feedback has been promoted as a useful adjunct to many health and well-being interventions, and has often been used as an additional support measure to pedometer-based interventions.[10] a systematic review by ogilvie et al.[11] in 2007 examined the effectiveness of interventions aimed at increasing the volume of walking. according to the review, the strongest evidence that exists supports interventions targeted at individuals motivated to change.[11] a further finding was that the interventions which involved strategies such as brief advice and the use of pedometers showed promising results, such as assistance with goal-setting, feedback on progress and strategies for overcoming barriers.[11] there is, however, a large gap between the development of effective pedometer-based interventions and their feasibility for use in public health practice. [12,13] a primary limitation is the high cost and large time demands on both staff and participants.[13] using more cost-effective intervention strategies, such as pedometer-based approaches supplemented by email-based feedback, may overcome this limitation. objectives the aims of this pilot study were therefore: (i) to evaluate the feasibility of a pedometer-based intervention complemented by individualised, email-based feedback promoting pa in an employed population; and (ii) to inform the development of, and calculate the recommended sample size for a pedometer-based intervention to be adminis tered in the future as a randomised, controlled trial (rct). methods the pilot study was conducted at a tertiary academic institution in kwazulu-natal province, south africa, through convenience sampling. an advertisement was emailed to all staff members within the faculty of health sciences inviting participation in the study. inclusion and exclusion criteria all willing participants aged 21 49 years were eligible. employees were excluded in the case of: pregnancy; diagnosis or treatment of cancer; mailto:pillayjd@dut.ac.za 16 sajsm vol. 26 no. 1 2014 any other physical/clinical condition that made pa difficult; contract workers whose employment with the company would end before the 12-week follow-up measurement; or non-compliance to a minimum of 3 days of blinded pedometer wear at baseline. ethical considerations and pre-participation screening this study was conducted in accordance with the declaration of helsinki, good clinical practice, as well as the ethical laws of south africa. ethical approval was obtained from the human research ethics committee of the faculty of health sciences, university of cape town (reference 044/2009). following agreement to participate in the study, the physical activity readiness questionnaire (par-q)[14] was administered to participants to ensure that there were no health risks associated with participation in pa. employees who agreed to study participation (n=25) were asked to sign an informed consent form prior to participation, and were assured that participation was voluntary and that they could withdraw at any time without penalty. the participants were also assured that their employer would not have access to any of the information collected, and that all information would be maintained as strictly confidential. measurements body height (cm) was measured using a height chart as the vertical distance from the floor to the vertex of the head. the participant stood barefoot with heels, buttocks and head in contact with the wall and arms at their side. waist circumference (cm) was measured using a tape measure around the skin of the waist. body weight was measured using an electronic scale (beurer ps 06), allowing only a single layer of clothing. the values were rounded to the nearest 100 g. body mass index (bmi) was computed as weight (kg) divided by height (m) squared. the omron body composition monitor (bf500) was used to measure percentage body fat, based on the principles of bioelectrical impedance.[15] blood pressure (bp) was recorded (mmhg) using a sphygmomanometer after the participant remained relaxed for 5 min. two readings were taken, approximately 5 min apart, and an average of the two readings was recorded. if the two were different from each other (>5 mmhg), a third reading was taken. the average of the two nearest readings was then used. following the 10-week intervention, both the ig and cg were required to complete follow-up measures, as in week 1. participants in the ig were invited to complete a questionnaire reporting their perceptions of the intervention. a section was included on general comments and/or suggestions for improvement of the intervention. both of these measures were used to inform the feasibility of the intervention. baseline pedometer wear all participants were required to wear an omron hj 750 itc pedometer attached to the hip area for 5 consecutive days. participants were asked to wear the pedometer throughout the day and to follow their usual routine of daily activities and to remove the pedometer only when bathing, showering or swimming. the pedometer screen was covered to reduce the likelihood of participants observing their daily steps, which might have influenced habitual levels of pa and subsequently the accumulation of daily steps during the baseline measurement. participants were informed that their daily results would be made available to them at the end of the 5-day period. allocation of participants to groups following the baseline feedback on participants’ pa levels from the data collected from the pedometers, participants were randomly allocated to an intervention group (ig) or a wait-listed control group (cg). by this random allocation, participants allocated to the cg would be offered the intervention following the study. the allocation of participants into ig and cg was achieved by random selection of participants from a composite participant list (microsoft excel). ig participants were provided with an unblinded pedometer for the subsequent 10 weeks. they were shown how to upload and interpret their pedometer data, and were requested to provide the pedometer data to the researcher, via email, bi-weekly. pedometer feedback upon return of the pedometer at baseline, data regarding steps per day were electronically uploaded by the researcher according to the omron health management manager software protocol.[16] this information was provided to participants. a unique feature of the pedometer is the ability to provide an hourly representation of steps per day. in addition to indicating total steps per day, the output can illustrate steps accumulated as being ‘aerobic’ or ‘non-aerobic’, according to the omron classification that integrates both intensity and duration. the number of steps classified as aerobic (>60 steps/min; minimum duration 1 min) and non-aerobic (<60 steps/min and/or duration <1 min) within the total steps per day record was therefore provided. similarly, total time spent accumulating aerobic steps (in min/day; aerobic time) could be identified. the pa recommendation of accumulating 30 min of moderate pa at least five times a week[1] was reinforced to all participants (i.e. ig and cg). all participants were encouraged to improve their pa levels steadily (e.g. by 10% per week, until 30 min of moderate pa was achieved) during the subsequent 10 weeks. the phrase ‘steps that count!’ was adopted as a strategy for engaging people into accumulating intensity-based steps. intervention participants in the ig continued to wear the pedometer (unblinded) for the subsequent 10 weeks. following the electronic, bi-weekly receipt of pedometer data from ig participants, ig participants were provided with individualised, emailed feedback and a generalised information sheet on ways to increase pa. the individualised feedback included information on the average daily steps per day accumulated, the highest number of steps per day accumulated by the individual over the past 2 weeks, the number of days (if any) that aerobic steps per day were accumulated, and the volume thereof in the form of a personalised email. the general supportive/motivational messages included a key message (such as ‘be active everyday’ or ‘walk tall’). a few strategies to increase pa (e.g. ‘use the stairs instead of the lift/escalator’; ‘walk fast enough so as to increase your breathing rate yet not feel out of breath’) were also suggested. the purpose of the bi-weekly email was to provide a summary of daily steps accumulated and to suggest some strategies to ‘add steps’ to one’s day. sajsm vol. 26 no. 1 2014 17 cg participants were similarly provided with a general motivational message (as in the ig) bi-weekly, but were not provided with a pedometer over the 10 weeks, and therefore no pedometer feedback. follow-up measures the ig and cg were required to repeat the measurements that were conducted at baseline during the week immediately after the 10week intervention. participants of the ig were invited to complete a questionnaire relating to their perceptions of the pilot intervention. outcome measures participants’ perceptions of the intervention, in terms of the value, appeal, support and benefits of the intervention, were identified. this served as a primary outcome measure in determining the feasibility of the intervention. a section on general comments and suggestions for improvement of the intervention was included. this provided insights into strengths and areas for improvement so that a more effective intervention could subsequently be developed and applied. the secondary outcome measures (daily pa levels in terms of steps per day as well as biometric and clinical measures) were assessed at baseline (week 1) and follow-up (week 12) for both ig and cg. this allowed us to detect changes in daily ambulatory pa and biometric measures over time as a function of the intervention. data were derived from the pedometer and expressed as steps per day. more importantly, information on the volume of sustained and moderate to vigorous intensity steps was assessed at baseline (week 1) and follow-up (week 12) for both the ig and cg. the change in steps per day at the end of the intervention directed us towards establishing an adequate sample size for a future rct protocol. statistical analyses table 1 summarises general study group characteristics. because of the pilot nature of this feasibility trial, we did not present statistical differences between groups for any of our measures. a descriptive analysis regarding barriers and facilitators of the intervention was performed on the information gathered from the questionnaire. from the questionnaire feedback, common emerging themes were identified in addition to facilitating factors and barriers to improving pa. participants’ perceptions on the value of the intervention were also identified so as to determine the feasibility of the intervention. results of the 25 participants who indicated an interest in study participation, 22 completed the baseline measures and pedometer wear and were randomly allocated to the cg or ig. two cg participants, upon being allocated to the cg, declined further participation in the study and one cg participant did not complete the pedometer wear and followup measures at week 12. a total of 11 ig (two male; nine females) and eight cg (one male, seven females) participants completed follow-up measures and were included in the final analysis. the data indicated that of the 11 ig participants, three accumulated some aerobic steps at baseline. none of the participants in the cg accumulated aerobic steps. it is noted that the ig was categorised into the ‘obese’ classification for bmi, while the cg was in the ‘overweight’ category for bmi. it was further noted that none of the participants in the cg had accumulated any aerobic steps at baseline. questionnaire evaluation on perceptions of the intervention most participants expressed that the pedometer inter vention was ‘catchy’ and that the pedometer served as a useful motivational aid and a reminder of the need to increase steps per day. participants also found the individualised feedback to be valuable in summarising their ambulatory pa over the 2-week period, and became more aware of the need to increase their steps per day. barriers identified by participants related mainly to adherence to the intervention, largely due to having a sedentary occupation and experiencing time limitations to incorporating pa into daily routine. participants also found it very difficult to achieve or increase their aerobic steps, despite an overall increase in the total volume of steps per day. participants indicated that their interest in the intervention decreased as the intervention continued. despite this, participants also felt that a longer intervention might have assisted them in further increasing their steps per day. the difference between baseline and follow-up measures within the study group was determined in order to establish the potential effect of the intervention on clinical measures (table 2). an interesting observation was that the average number of aerobic steps per day decreased at follow-up in the ig, notwithstanding the small number of steps and the very large standard deviation. the time spent accumulating aerobic steps increased in the ig. the daily steps, however, increased by almost 1 000 steps in the ig v. 97 steps in the cg. no aerobic steps were accumulated at baseline and follow-up in the cg for comparative purposes. power calculation and sample size estimation for a future rct a power analysis for a two-group, independent sample t-test was conducted using the gpower data analysis website.[17] based on a minimum improvement of 1 000 steps/day, as established from this table 1. descriptive baseline characteristics of participants (n=19) variable* cg (n=8) ig (n=11) age (years) 38.3±7.7 37.6±8.6 body height (cm) 168.9±5.0 165.1±8.3 body waist (cm) 84.6±9.9 91.9±13.7 body fat (%) 36.0±9.5 42.8±8.9 bmi (kg/m2) 26.0±4.5 31.1±6.6 body weight (kg) 74.4±14.0 84.4±17.4 sbp (mmhg) 118±16 118±13 dbp (mmhg) 80±11 85±14 total steps per day (steps/day) 4 600±2 041 5 370±1 739 aerobic steps (steps/day) 0 331±646 aerobic time (min) 0 19.3±39.3 cg = control group; ig = intervention group; bmi = body mass index; sbp = systolic blood pressure; dbp = diastolic blood pressure. *all values are expressed as means ± standard deviations. 18 sajsm vol. 26 no. 1 2014 pilot study, a sample size of approximately 85 participants per arm of the study is required to ensure 80% statistical power and a p-value <0.05. considering this possibility and the likelihood of performing subgroup analyses based on factors such as age and gender, as well as the possibility of loss to follow-up, we estimate that a sample size of 150 participants in the ig and cg, respectively, would be an appropriate target sample. discussion the purpose of this study was to evaluate the feasibility of a pilot intervention aimed at improving the daily ambulatory pa in an employed, south african adult population. a further objective was to use the outcomes of the study (i.e. changes in steps per day between baseline and follow-up) to inform the development of, and calculate the recommended sample size for, a pedometer-based intervention protocol, to be administered as a future rct. evaluation on perceptions of the intervention adherence to pa emerged as a limitation to increasing steps per day. this was expressed to be largely due to being sedentary at work and experiencing time limitations in incorporating pa into daily routine. several studies, as reported by fox et al.,[18] show similar findings and a growing body of research supports the need to build pa into daily routine.[9] interventions may also need to focus on institutionallevel efforts to support building activity into daily routines.[18] such support measures can include creating walk-paths around the work environment or incorporating a pa programme into the work day. [18] additional measures include using motivational prompts encouraging/ reminding people to be more active during work-time, or foot-markers directing people to the stairwell instead of the lifts.[18] pedometer outcomes due to the small sample size, it would be inappropriate to draw conclusions based on statistical analysis from the pedometer results. a useful finding, nevertheless, was the overall increase in total steps per day in the ig of approximately 1 000 steps/day. recently published papers and systematic reviews of pedometer-based interventions conducted between 1966 and 2007[11,18,19] show an average improvement of 1 500 3 000 steps/day. these studies, however, generally showed a higher baseline steps per day volume than our study group (7 500 steps/day v. 5 000 steps/day, respectively). no reference has been made to intensity-based steps in any of these previous interventions. our study, therefore, provides some information on intensity of steps per day and identifies intensity-based messages as a strategy towards improved health outcomes. modifications of the pilot study for future rct application the allocation of participants to a future trial should be based on a theoretical model for behavioural change; e.g. the intervention should be targeted towards participants at a specific stage of behavioural change, so as to be mentored similarly to ensure improved uptake, compliance and overall impact of the intervention in terms of increased pa. as such, the intervention can be targeted specifically at individuals not meeting current guidelines and in the contemplation stage of behavioural change, as per the trans-theoretical model of behavioural change.[20] the emailed messages delivered to participants should include additional information and not only a summation of steps accumulated. typically, the information must also indicate how the results relate to current pa guidelines or intensity-based steps per day targets. this will contribute towards the reinforcement of public health recommendations that may prompt individuals to self-reflect on current pa levels, in keeping with pre-determined goals. the importance of intensity-based steps should be reinforced further during the bi-weekly feedback emails, with particular emphasis on current pa guidelines. this includes a combination of duration and intensity-based steps data rather than volume-based information. this may require revision of the current ‘aerobic’ classification used by the pedometer, as determined in recent studies.[8,21-25] the general information provided to the ig and cg was the same irrespective of individual progress towards improved ambulatory pa. depending on the extent of available resources, tailored feedback can be provided at an individual level based on the level of progress. in a similar manner, barriers towards progress can be identified with improvement strategies provided on a more individual basis. study strengths and limitations the study is among the first pedometer-based interventions conducted in south africa. more importantly, this pilot intervention informs the development and protocol of a pedometer-based intervention that can be applied on a larger scale and in a wider context. in terms of study limitations, the small sample size and the element of selection bias (as the study involved selection from a convenience sample of persons) were primary limitations. also, the sample was taken from a health sciences faculty, and might not have been representative of staff in other faculties in terms of knowledge and interest in pa and health. waist circumference was measured using a tape measure around the skin of the waist. more recent recommendations[26] for measuring waist circumference can be applied in future studies. we noted a difference in bmi between the ig and cg at baseline and acknowledge that this might have had an effect on the steps per day data recorded at follow-up. similarly, none of the participants table 2. net change in characteristics at follow-up (n=19) variable* cg (n=8)† ig (n=11)† waist circumference (cm) -0.38±2.0 +0.73±2.7 body fat (%) +0.26±1.3 +1.34±1.9 bmi (kg/m2) +0.13±0.5 +0.26±0.58 body weight (kg) +0.3±1.3 +0.67±1.6 sbp (mmhg) -0.8±8.0 +0.3±8.9 dbp (mmhg) -3.1±3.7 -2.5±7.6 daily steps (steps/day) +97±750 +996±1 748 daily aerobic steps (steps/day) 0 -54±2 746 daily aerobic time (min) 0 +0.9±23.0 cg = control group; ig = intervention group; bmi = body mass index; sbp = systolic blood pressure; dbp = diastolic blood pressure. *all values are expressed as means ± standard deviations. † a + symbol indicates an improvement in the desired direction; a symbol indicates a decrease in the desired direction. sajsm vol. 26 no. 1 2014 19 in the cg accumulated any aerobic steps at baseline. as such, the difference between the two groups at baseline might have contributed to the difference observed between the groups at follow-up. the cg received the same general motivational messages as the ig bi-weekly, which might have led to increased pa in the cg. no theoretical model for behavioural change was applied; this implied that, using a convenience sample approach, participants were at various stages of change towards improving ambulatory pa. the study might therefore have included participants who were already meeting current pa guidelines and were interested in further improving this through the intervention. the emailed feedback messages provided to ig participants only provided a summation of pedometer results, but did not indicate how this related to current guidelines or intensity-based steps per day targets as a method of reinforcement. conclusion this pilot study provides useful information on the potential for pa improvements through pedometry in an employed, adult group. in so doing, the study provides a basis to further pedometer-based interventions that can be applied in other contexts and settings and on a larger scale. consequently, this pilot intervention informs the development and protocol of a large-scale intervention to be applied as an rct. funding acknowledgements. durban university of technology (dut) and the national research foundation (thuthuka). references 1. haskell wl, i-min l, pate rr, et al. physical activity and public health: updated recommendation for adults from the american college of sports medicine and the american heart association. circulation 2007;116(9):1081-1093. [http://dx.doi. org/10.1161/circulationaha.107.185649] 2. tudor-locke c. promoting lifestyle physical activity: experiences with the first step program. am j lifestyle med 2009;3(1 suppl):50s-54s. 3. pillay jd, kolbe-alexander tl, achmat m, carstens m, lambert ev. are pointof-decision prompts in sports science and medicine centre effective in changing the prevalence of stair usage? a preliminary study. south african journal of sports medicine 2009;21(2):58-64. 4. tudor-locke c. taking steps toward increased physical activity: using pedometers to measure and motivate. washington dc, usa: president's council on physical fitness and sports, 2002. 5. richardson cr, newton tl, abraham jj, sen a, jimbo m, swartz am. a metaanalysis of pedometer-based walking interventions and weight loss. ann fam med 2008;6(1):69-77. [http://dx.doi.org/10.1370/afm.761] 6. freedson ps, miller k. objective monitoring of physical activity using motion sensors and heart rate. res q exerc sport 2000;71(2 suppl):s21-s29. 7. welk gj, corbin cb, dale d. measurement issues in the assessment of physical activity in children. res q exerc sport 2000;71(2 suppl):59-73. 8. tudor-locke c, sisson sb, collova t, lee sm, swan pd. pedometer-determined step count guidelines for classifying walking intensity in a young ostensibly healthy population. can j appl physiol 2005;30(6):666-676. 9. bravata dm, smith-spangler cs, sundaram v, et al. using pedometers to increase physical activity and improve health a systematic review. jama 2007;298(19):22962304. 10. harrington ng, noar sm. reporting standards for studies of tailored interventions (r2). health educ res 2012;27(2):331-342. [http://dx.doi.org/10.1093/her/cyr108] 11. ogilvie d, foster ce, rothnie h, et al. interventions to promote walking: systematic review. bmj 2007;334:1204-1214. 12. lenfant c. shattuck lecture-clinical research to clinical practice-lost in translation? n engl j med 2003;349(9):868-874. 13. glasgow re, emmons km. how can we increase translation of research into practice? types of evidence needed. annu rev public health 2007;28(1):413-433. 14. chisholm dm, collis ml, kulak ll, davenport w, gruber n, stewart gw. par-q validation report: the evaluation of a self-administered pre-exercise screening questionnaire for adults. victoria, canada: bc ministry of health and welfare, 1978. 15. bosy-westphal a, later w, hitze b, et al. accuracy of bioelectrical impedence consumer devices for measurement of body composition in comparison to whole body magnetic resonance imaging and dual x-ray absorptiometry. obes facts 2008;1:319-324. [http://dx.doi.org/10.1159/000176061] 16. incorporated oh. instruction manual: pocket pedometer-model hj-720itc2007. 17. g*power version 3.0.10. power analysis for two-group independent sample t-test. http://www.ats.ucla.edu/stat/gpower/indepsamps.htm (accessed 16 october 2012). 18. fox am, mann dm, ramos ma, kleinman lc, horowitz cr. barriers to physical activity in east harlem, new york. j obes 2012;719140. [http://dx.doi. org/10.1155/2012/719140] 19. chan cb, ryan daj, tudor-locke c. health benefits of a pedometer-based physical activity intervention in sedentary workers. prev med 2004;39:1215-1222. 20. prochaska jo, velicer wf. the transtheoretical model of health behavior change. am j health promot 1997;12(1):38-48. 21. marshall sj, levy ss, tudor-locke ce, et al. translating physical activity recommendations into a pedometer-based step goal: 3000 steps in 30 minutes. am j prev med 2009;36(5):410-415. [http://dx.doi.org/10.1016/j.amepre.2009.01.021] 22. pillay jd, kolbe-alexander tl, van mechelen w, lambert ev. steps that count the association between the number and intensity of steps accumulated and fitness and health measures. j phys act health 2012 (in press). [http://dx.doi.org/10.1186/14712458-12-880] 23. pillay jd, kolbe-alexander tl, proper ki, van mechelen w, lambert ev. steps that count physical activity recommendations, brisk walking and steps per minute how do they relate? j phys act health 2013 (in press). 24. abel m, hannon j, mullineaux d, beighle a. determination of step rate thresholds corresponding to physical activity intensity classifications in adults. j phys act health 2011;8(1):45-51. 25. tudor-locke c, camhi sm, leonardi c, et al. patterns of adult stepping in the 2005/2006 nhanes. prev med 2011;53(3):178-181. [http://dx.doi.org/10.1016/j. ypmed.2011.06.004] 26. stewart a, marfell-jones m, olds t, de ridder h. international standards for anthropometric assessment. lower hutt, new zealand: isak, 2011. http://dx.doi.org/10.1161/circulationaha.107.185649] http://dx.doi.org/10.1161/circulationaha.107.185649] http://dx.doi.org/10.1370/afm.761] http://dx.doi.org/10.1093/her/cyr108] http://dx.doi.org/10.1159/000176061] http://www.ats.ucla.edu/stat/gpower/indepsamps.htm http://dx.doi.org/10.1155/2012/719140] http://dx.doi.org/10.1155/2012/719140] http://dx.doi.org/10.1016/j.amepre.2009.01.021] http://dx.doi.org/10.1186/1471-2458-12-880] http://dx.doi.org/10.1186/1471-2458-12-880] http://dx.doi.org/10.1016/j.ypmed.2011.06.004] http://dx.doi.org/10.1016/j.ypmed.2011.06.004] sajsm 603 (case report).indd case report sajsm vol. 27 no. 1 2015 23 primary spontaneous pneumothorax (psp) is relatively uncommon in the athletic population. because of the subtle nature of the symp toms, the diagnosis is easily missed, which can lead to unnecessary prolonged discomfort and recovery time for the athlete. �ere is currently a lack of evidence in the literature concerning treatment and return-to-play protocols referring speci�cally to psp within the athletic community. �is case report highlights the predisposing and important factors in the history of a 34-year-old recreational male athlete who developed psp. according to the knowledge of the authors, this report of psp in a recreational athlete is the �rst of its kind described in south africa. owing to the possibility of life-threatening complications, it is important for sports physicians to be familiar with the important points in the history and to be made aware of the predisposing factors that may lead to psp. s afr j sports med 2015;27(1):23-24. doi:10.7196/sajsm.603 primary spontaneous pneumothorax in a recreational athlete f j van der col�,1,2 mb chb; d c janse van rensburg,2,3 md 1 private practitioner, potchefstroom, south africa 2 section sports medicine, faculty of health sciences, university of pretoria, south africa 3 exercise smart team, university of pretoria, south africa corresponding author: f j van der col� (medfvandercol�@yahoo.com) pneumothorax is defined as the presence of gas in the pleural cavity.[1] this can occur spontaneously or subsequent to direct trauma to the chest wall. primary spontaneous pneumothorax (psp) occurs in the absence of any underlying lung pathology,[1-3] and although it is a well-recognised and well-described cause of acuteonset chest pain, the prevalence of this condition in the athletic community is uncommon. �is may be owing to the low incidence of this condition in athletes, underreporting of cases and possibly missed diagnoses. tension pneumothorax is an extremely rare but life-threatening complication of psp, and if suspected, should be treated as a medical emergency.[2] �is case report describes a rare occurrence of psp in a recreational athlete and focuses on the athlete’s medical history as well as the epidemiology and predisposing factors that may lead to psp. case report �is case involves a 34-year-old male who worked as an engineer at a steel production plant. he participated in a number of indoor and outdoor sports. in his medical history, it was noted that he su�ered from gastro-oesophageal re�ux disease (gerd) secondary to a hiatus hernia, which was diagnosed in 2009. no further medical problems were reported. no known allergies were reported and he did not smoke. he did, however, have a positive family history, with one female sibling having developed psp in recent years. six weeks prior to the onset of his symptoms, he competed in a high-altitude ultra-marathon trail run in cold and wet conditions. on the day before his symptoms started, he was playing action cricket. he did not experience any symptoms and or sustain any direct trauma to the chest wall during the match. he presented to his general practitioner (gp) with complaints of acute-onset chest pain on the right side, which woke him during the night. �e pain progressively worsened the following day and did not respond to analgesic or antacid treatment. he did not complain of any shortness of breath, and attributed the pain to acid re�ux. �e examination was noted to be unremarkable, with normal lung and heart sounds and normal vital signs. his gp agreed that the pain might be due to gerd. antire�ux treatment was prescribed and he was sent home. �e pain gradually subsided over the following 5 days. a�er 2 weeks of rest, he played another match of action cricket, but had to withdraw from the match because of chest pain and shortness of breath. a follow-up appointment with his gp was scheduled 3 weeks a�er the initial appointment. immediate chest radiographs were ordered, which showed a large pneumothorax with 60% of the pleural space occupied by air on the right side of the chest (fig. 1). no mediastinal shi� was noted on the fig. 1. x-ray of lungs clearly demonstrating pneumothorax on the right. 24 sajsm vol. 27 no. 1 2015 radiograph. he was urgently referred to a cardiothoracic surgeon and was taken to the operating theatre the following day for a diagnostic bronchoscopy. �e cause of the pneumothorax was found to be a ruptured bulla in the apex of the right lung. �e surgeon continued to do a right posterolateral minithoracotomy, drained the organising pleural e�usion, and performed a bullectomy and complete parietal pleurectomy of the right lung. �e pleura of the right lung were sent to the laboratory for histology, including ziehl-neelson staining to exclude tuberculosis infection and periodic acid-schi� (pas) staining to exclude fungal infection. histology showed an eosinophylic pleuritis with reactive mesothelial hyperplasia. �e ziehl-neelson stain and pas stain both came back negative. he was discharged from hospital a few days later and his recovery since then has been uneventful. discussion pneumothoraces can broadly be categorised as either traumatic or spontaneous. spontaneous pneumothorax can further be subdivided into two groups: primary spontaneous pneumothorax (psp), where there is no history of underlying lung pathology; and secondary spontaneous pneumothorax (ssp), where there is pre-existing lung pathology.[1-3] psp is more common in males, with an incidence of 7.4 18 cases/100  000/year in males, and 1.2 6 cases/100  000/year in females.[2,3] other risk factors include smoking and being a tall, thin male between the ages of 10 and 30 years.[3] almost 10% of cases have a positive family history of psp, which is linked to a speci�c gene mutation, folliculin, associated with a rare disease called birt-hoggdubé syndrome.[3] changes in climate, with decreased atmospheric pressures and colder temperatures, have been identi�ed as possible contributing factors in psp.[4] �e most common presenting symptoms of psp are acute-onset pleuritic chest pain and shortness of breath, which may improve over a period of 24 hours.[3] chest pain is an important and reliable symptom that is present in 80 95% of cases.[5] the physical examination may reveal a decrease in breath sounds on the a�ected side, with hyper-resonance on percussion, crepitus on palpation and tracheal shi�.[6] �ese signs may be very di�cult to elicit in a small pneumothorax, and a physician should have a high index of suspicion from the history. �e threshold for ordering chest radiographs should be very low if a possible pneumothorax is suspected. �e majority of cases occur during rest, with <10% of spontaneous pneumothoraces occurring during exercise. �e major cause of psp seems to be the rupture of bullae in the apices of one or both lungs. �e exact cause of these bullae still remains unclear and warrants further investigation.[2,3] psp seems to be a rare condition among the athlete population. in this case report, it is evident that the athlete had a number of risk factors, including sex, age, exposure to cold weather conditions and decreased atmospheric pressure, as well as a positive family history, all of which need to be taken into account when an athlete presents with acute-onset chest pain. �e recording of cases of psp in the athletic community speci�cally is encouraged to help guide sports physicians to better diagnose and manage this condition. the research and development of safe return-to-play guidelines for these athletes are also recommended. references 1. braunwald e, fauci as, kasper dl, eds. harrison’s principles of internal medicine. 15th ed. new york: mcgraw-hill, 2001. 2. noppen m. spontaneous pneumothorax: epidemiology, pathophysiology and cause. eur respir rev 2010;19(117):217-219. [http://dx.doi.org/10.1183/09059180.00005310] 3. luh s. diagnosis and treatment of primary spontaneous pneumothorax. j zhejiang univ sci b 2010;11(10):735-744. [http://dx.doi.org10.1631/jzus.b1000131] 4. haga t, kurihara m, kataoka h, ebana h. in�uence of weather conditions on the onset of primary spontaneous pneumothorax: positive association with decreased atmospheric pressure. ann �orac cardiovasc surg 2013;19(3):212-215. [http:// dx.doi.org/10.5761/atcs.oa.12.01884] 5. sik ec, batt me, heslop lm. atypical chest pain in athletes. curr sports med rep 2009;8(2):52-58. [http://dx.doi.org/10.1249/jsr.0b013e31819c7d01] 6. mensinger jm. pneumothorax in a recreational athlete. int j athl ther train 2013;18(6):27-31. sajsm cpd the cpd programme for sajsm is being administered by medical practice consulting. cpd questionnaires must be completed online at www.mpconsulting.co.za a maximum of 3 ceus will be awarded per correctly completed test. march 2015 instructions 1. the sajsm march issue questionnaire can be found online at www.sajsm.org.za 1. read the journal. all the answers will be found there. 2. go to www.mpconsulting.co.za to answer the questions. accreditation number: mdb015/166/02/2015 (clinical) the easy choice 2015/02/17 3:08 pm original research 18 sajsm vol. 25 no. 1 2013 background. physical activity (pa) has been described as medicine, owing to the clear evidence for its role in the prevention and management of various diseases. objectives. to determine the knowledge, perceptions and attitudes of south african general practitioners (gps) towards the promotion of pa. methods. a total of 255 private-sector gps from various provinces in sa participated in our cross-sectional study, by completing a selfreport questionnaire surveying their knowledge, perceptions and attitudes towards the promotion of pa. results. the findings indicated that south african gps in general do promote pa to their patients for treatment and health promotion. the majority of gps in our study strongly believed that promoting pa is an important part of primary healthcare. the gps frequently promoted exercise in the treatment of obesity, type 2 diabetes and hyperlipidaemia. conclusion. south african gps appear to be recommending pa to their patients at a primary-care level. clear practice guidelines are needed to promote pa in a way that will have a population-level impact. to aid this, gps are encouraged to provide written information to promote pa in a way that will have an effect. s afr j sm 2013;25(1):18-22. doi:10.7196/sajsm.368 do south african general practitioners believe that ‘exercise is medicine’? e d watson, t khan, c m crear centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa e d watson, ba hons (biokinetics), msc (sport sc) t khan, bhsc c m crear, ba (sport psych) corresponding author: e d watson (estelle.watson@wits.ac.za) exercise is a type of physical activity (pa) that is structured, planned and designed to improve fitness. it is well established that pa is associated with positive health gains. there is clear evidence for its role in prevention and management of various non-communicable diseases such as heart disease, diabetes mellitus, hypertension and some cancers.[1,2] furthermore, regular pa is an essential tool in maintaining a healthy body weight.[3] finally, pa is associated with decreased mortality and morbidity.[4] it can, therefore, confidently be seen as a much-needed treatment to prevent chronic disease and prolong life. despite this evidence, south africa (sa) appears to be a relatively inactive nation. an estimated 46% of south africans do not meet the required 150 min of moderate exercise per week.[5] furthermore, physical inactivity in sa accounts for 3.3% of deaths per year and 1.1% of disability-adjusted life years (dalys).[6] non-communicable diseases account for 21% of life years lost in sa.[7] diabetes alone is estimated to have caused 4.3% of all deaths in sa in 2000.[8] without a doubt, physical inactivity in sa is a costly healthcare burden. promoting pa in primary care could provide a cost-effective solution. it has been termed public health’s ‘best buy’ and ‘exceptional value for money’.[3,9] for example, a sedentary patient is estimated to cost the healthcare system r2 200 more per year than an active patient, and that cost may increase to as much as r13  000 with associated overweight or obesity.[10] in contrast, engaging in pa can lower healthcare charges by up to 4.7% per active day per week.[11] in canada, a reduction in physical inactivity by as little as 10% has the potential to reduce expenditure by us$150 million per year. [12] therefore, with its clear benefits and cost implications, exercise has been termed a possible ‘wonder drug’.[3] however, exercise prescription is not yet a part of standardised practice in primary care. various exercise-referral schemes have aimed to tackle this issue, making activity assessment and prescription a standard part of disease prevention and management. one such initiative, exercise is medicine (http://www.exerciseismedicine.org), has recently included the south african sports medicine association (sasma) into its exercise is medicine global network.[13] yet, there is considerable uncertainty regarding the effectiveness of such exercisereferral schemes. in a recent systematic review, pavey and colleagues[14] found weak evidence for a short-term increase in pa of sedentary patients with such schemes. however, the review demonstrated the lack of quality research in this area. in addition, little is known about the attitudes towards exercise prescription in mainstream medicine. it has been suggested that general practitioners (gps) have insufficient knowledge to give effective pa advice.[14] in contrast, it may be that gps have the knowledge needed, but do not promote pa in a way that will have an impact.[15] to date, no research has yet been done mailto:estelle.watson@wits.ac.za http://www.exerciseismedicine.org sajsm vol. 25 no. 1 2013 19 to determine the knowledge, perceptions and attitudes of sa gps towards pa promotion. methods a total of 255 gps from various provinces in sa participated in the cross-sectional survey. gps were excluded if they were working for the public sector, in practice for <3 years, not registered with the health professions council of south africa (hpcsa), or specialist physicians. a questionnaire was adapted from a previous study by lawlor et al.[15] and piloted for content and construct validity. questions were designed to require the selection of answers from a list of options or a likert-type scale. questionnaires were distributed: (i) via an appointment at gp practices located from the hpcsa website (http://www.hpcsa.co.za); and (ii) electronically via an email containing a hyperlink to the questionnaire housed online on survey monkey (http://www.surveymonkey.com). in addition, a medical directory service, medpages, circulated the hyperlink to their distribution list of gps. informed consent was obtained by selecting the link to the questionnaire. ethics approval was obtained from the human research ethics committee (hrec) of the university of the witwatersrand (reference m120405). results the demographic distribution of the participant gps is shown in table 1. the majority (38%) were practising in gauteng province. perceptions, attitudes and beliefs when asked ‘do you promote pa to your patients?’, 213 (84%) gps answered ‘yes’, 2 (1%) answered ‘no’, and 39 (15%) responded ‘sometimes’. of those who answered the question affirmatively, 217 (87%) stated the reason as being for treatment and health promotion, 6 (2%) stated the reason as being for treatment alone, and 23 (9%) stated that the sole reason was for the purposes of health promotion. the response of the gps to a number of attitudinal statements is depicted in table 2. almost all gps stated that they regularly advised their patients on the benefits of pa. over three-quarters believed that they could be effective in persuading patients to increase their pa levels, and most believed they were equipped with the necessary knowledge. the majority of responders strongly believed that promoting pa is an important part of primary healthcare. table 3 summarises the responses of gps to statements regarding conditions for which they were most likely to give advice. the condition most likely to receive frequent advice on pa was overweight and obesity followed by type 2 diabetes mellitus (dm). a large majority of responders also indicated that they would provide pa advice for hyperlipidaemia, type 1 dm and hypertension. on the other hand, approximately one-third indicated that they would never provide pa advice to patients with cystic fibrosis, multiple sclerosis (ms), parkinson’s disease (pd) and alzheimer’s disease. knowledge the gps’ knowledge of the conditions for which there is evidence for the beneficial effects of pa is shown in table 4. the gps’ knowledge of the evidence for the benefits of pa in hypertension, psychological wellbeing, muscular strength and weight control was good. responses varied across the spectrum for the evidence for pa in alzheimer’s disease and risk of breast cancer. the gps’ knowledge of exercise prescription and current recommendations of the levels of activity required was further assessed through a series of questions. the table 1. demographic distribution of gp participants province n (%) gauteng 83 (38) western cape 47 (22) kwazulu-natal 31 (14) eastern cape 17 (8) limpopo 11(5) free state 11 (5) mpumalanga 6 (3) north west 6 (3) northern cape 5 (2) no answer 39 (15) table 2. responses to statements relating to attitudes of gps towards promoting pa statement n (%) strongly agree agree disagree strongly disagree unsure i regularly advise my patients about the benefits of pa 146 (58) 99 (39) 9 (4) 0 (0) 0 (0) i believe that i can be effective in persuading patients to increase their pa levels 89 (35) 120 (48) 28 (11) 4 (2) 11 (5) i have sufficient knowledge to advise patients about pa 71 (28) 142 (56) 29 (12) 2 (1) 9 (4) i try to encourage as many patients as possible to increase or continue their pa levels 106 (43) 123 (49) 16 (6) 1 (0) 3 (1) i only discuss pa if the patient mentions it 7 (3) 19 (8) 106 (42) 114 (45) 9 (4) promoting pa is an important part of primary healthcare 190 (75) 61 (24) 1 (0) 2 (1) 0 (0) any amount of pa is beneficial to health 134 (54) 95 (38) 17 (7) 5 (2) 0 (0) only vigorous/strenuous activity is beneficial to health 4 (2) 12 (5) 133 (53) 90 (36) 14 (6) pa = physical activity. http://www.hpcsa.co.za http://www.surveymonkey.com 20 sajsm vol. 25 no. 1 2013 majority of gps (96%) indicated that they would recommend aerobic exercise 3 5 days per week. most (89%) indicated that they would advise a 20 40-min duration of pa to gain benefits; however, over half (55%) believed that exercise at 70 80% of the maximum heart rate (hrmax) was required to obtain such benefits. the majority of the gps (86%) agreed that resistance training results in health benefits, and 96% believed that flexibility exercises result in health benefits. patient education and referral fifty-four (21%) gps indicated that they provided written material regarding pa to their patients, typically disseminated in the form of their own advice (65%) or available brochures (44%). other handouts and online information were used in less than one-third of cases. the most common type of pa recommended by gps was walking (89%), followed by running (46%), joining a gym (44%), swimming table 3. conditions for which gps indicated they would give advice regarding pa condition n (%) always sometimes occasionally never arthritis 109 (45) 89 (37) 34 (14) 12 (5) rheumatoid arthritis 86 (36) 83 (35) 51 (21) 18 (8) sports injuries 152 (62) 65 (27) 18 (7) 10 (4) occupational injuries 102 (42) 96 (40) 36 (15) 8 (3) back pain 162 (65) 62 (25) 21 (8) 5 (2) hypertension 178 (72) 53 (21) 15 (6) 3 (1) heart failure 74 (30) 76 (31) 60 (24) 36 (15) hyperlipidaemia 188 (75) 40 (16) 15 (6) 7 (3) angina/ischaemia 88 (36) 86 (35) 38 (16) 31 (13) asthma 97 (40) 81 (33) 43 (18) 23 (9) copd 60 (25) 89 (37) 55 (23) 37 (15) cystic fibrosis 44 (20) 52 (23) 40 (18) 88 (39) obesity/overweight 230 (91) 16 (6) 6 (2) 0 (0) type 1 dm 183 (73) 42 (17) 23 (9) 3 (1) type 2 dm 210 (84) 28 (11) 11 (4) 0 (0) thyroid disorders 62 (26) 80 (32) 60 (25) 41 (17) ms 39 (17) 49 (22) 69 (30) 71 (31) depression 152 (61) 60 (24) 25 (10) 14 (6) pd 39 (17) 58 (25) 67 (29) 69 (30) alzheimer’s disease 36 (16) 50 (22) 70 (30) 74 (32) opportunistically in all patients 83 (36) 96 (41) 38 (16) 17 (7) copd = chronic obstructive pulmonary disease; dm = diabetes mellitus; ms = multiple sclerosis; pd = parkinson’s disease. table 4. gp knowledge regarding evidence for the beneficial effects of pa on various conditions statement regarding condition n (%) strong evidence some evidence no evidence unsure reduces risk of hypertension 212 (83) 37 (15) 4 (2) 2 (1) reduces blood pressure in known hypertensives 212 (83) 37 (15) 2 (1) 3 (1) reduces death from ischaemic heart disease 175 (69) 61 (24) 4 (2) 12 (5) reduces risk of alzheimer’s disease 40 (16) 87 (35) 39 (16) 83 (33) improves psychological well-being 211 (84) 35 (14) 1 (0) 4 (2) reduces risk of breast cancer 42 (17) 79 (32) 45 (18) 84 (34) improves muscular strength 231 (91) 21 (8) 0 (0) 2 (1) assists in weight control 223 (88) 31 (12) 0 (0) 0 (0) sajsm vol. 25 no. 1 2013 21 (43%) and cycling (38%). in response to being asked to whom they would most likely refer their patients, the most popular route of referral by the gps was to a biokineticist, followed by to a gym and a physiotherapist (fig. 1). discussion gps are in a unique position to provide advice on, and promote, pa on a primary-care level. this study indicates that sa gps regularly advise on the benefits of pa, and promote pa to as many of their patients as possible. in addition, they appear to be confident and enthusiastic about providing pa advice. our study found that more sa gps felt that they had sufficient knowledge to advise patients on pa, than their uk counterparts.[15,16] the belief that promoting pa is an important part of primary healthcare was felt more strongly in our group than in any other study.[15-17] this implies that sa gps have bought into the notion that exercise is medicine, and agree that they have a role to play in promoting pa to their patients. the patients most likely to receive advice on pa were those with chronic diseases of lifestyle, such as overweight, diabetes, hyperlipidaemia and hypertension. we compared the present data with those of other studies and found that sa gps consistently had one of the highest rates of ‘always’ advising pa for these conditions. [15,17-19] in addition, our findings showed that sa gps frequently provide advice opportunistically in all patients. this is perhaps reflective of their beliefs on the importance of pa in primary healthcare. on the other hand, despite the growing body of evidence to suggest that regular pa may improve the physical outcomes and reduce the rate of progression of neurological diseases such as pd and ms,[20,21] only a minority of gps advised patients with these diseases on the benefits of pa. it is important for patients to receive the correct information in order to undertake sufficient pa for health benefits. largescale epidemiological studies have reported on the dose-response relationship between pa and health. this has led to recommendations for pa to include 150 min of moderate-intensity aerobic activity or 70 min of vigorous-intensity aerobic activity, or a combination of the two, each week.[3] generally, the knowledge of gps regarding the frequency and duration of pa required for health benefits was good. however, over half of the gps believed that one needed to exercise at vigorous intensity in order to gain health benefits. this is despite several published guidelines that include both moderateand vigorous-intensity exercise, with the former being presumably safer and more practical for the general public. perhaps the area where gps require assistance is in the method in which pa is promoted. in our study, very few gps reported providing any written information to their patients. to this end, exercisereferral schemes, specifically exercise is medicine, provide useful resources such as information and brochures. likewise, gps should be encouraged to refer their patients to other professionals. sa is unique in that it is one of the only countries to have a dedicated healthcare professional type, a biokineticist, specialising in the prescription of exercise and promotion of pa. notably, over one-quarter of the gps in our sample did not refer their patients for exercise, and less than one half referred their patients to a biokineticist and gym, in line with a similar study by barrett et al.[18] this is despite encouragement in the current literature to connect primary care with other professionals in the pursuit of promoting pa.[3] study limitations a limitation of our study is the traditionally low response rate in gp surveys; albeit, our study had a similar response rate to that of other studies.[16] admittedly, it is hard to believe that, with the majority of gps promoting pa, it has not made a bigger impact on the health of the nation. therefore, it is safe to assume that this study may not be reflective of sa gps as a whole. further studies should be aimed at adding to this research on a wider scale. a second limitation is that our study did not address the possible barriers to pa promotion. time constraints, lack of protocols, education and training, and other priorities have all been cited in the literature as possible barriers to promoting pa on a primary care level.[22] further research should address the potential and perceived barriers to the implementation of the exercise is medicine scheme in sa. conclusion gps are the cornerstone of public health, and they have the potential to influence population levels of activity on a large scale. physicians have been shown to be effective in changing smoking behaviours, and we should expect the same for physical inactivity.[23] in patients who require more supportive measures, gps are encouraged to provide standardised educational material and to refer to specialised professionals such as biokineticists, physiotherapists or fitness trainers. it can be concluded that gps agree on the importance of pa promotion in primary care, and believe they have a role to play in this area. clear practice guidelines are needed to promote pa in a way that will have an impact at the population level. to this effect, exercise is medicine in the sa context brings with it exciting prospects. moreover, fig. 1. gps’ preferred route of referral. pa is free and consequently a viable alternative to pharmaceuticals. for a resource-scarce country such as sa, the promotion of pa at a primary care level could have a massive impact on the health and longevity of the nation. acknowledgements. the authors thank all participant gps, as well as the marketing department of medpages for assistance in distributing the survey. references 1. vuori i, andersen lb. exercise as disease prevention. in: kjaer m, krogsgaard m, magnusson p, et al., eds. textbook of sportmedicine: basic science and clinical aspects of sports injury and physical activity. london: blackwell science, 2003:315336. [http://dx.doi.org/10.1002/9780470757277.ch15] 2. bauman ae. updating the evidence that physical activity is good for health: an epidemiological review 2000–2003. j sci med sport 2004;7(1):6-19. [http://dx.doi. org/10.1016/s1440-2440(04)80273-1] 3. sallis r. exercise is medicine and physicians need to prescribe it! br j sports med 2009;43(1):3-4. [http://dx.doi.org/10.1136/bjsm.2008.054825] 4. haskell wl, lee i, pate rr, et al. physical activity and public health: updated recommendation for adults from the american college of sports medicine and the american heart association. med sci sports exerc 2007;39(8):1423. [http://dx.doi. org/10.1249/mss.0b013e3180616b27] 5. van zyl s, van der merwe lj, walsh cm, groenewald aj, van rooyen fc. risk-factor profiles for chronic diseases of lifestyle and metabolic syndrome in an urban and rural setting in south africa. african journal of primary health care & family medicine 2012;4(1):1-10. [http://dx.doi.org/10.4102/phcfm.v4i1.346] 6. walter cm, du randt r, venter djl. the physical activity and health status of two generations of black south african professional women. health sa gesondheid 2011;16(1):1-9. [http://dx.doi.org/10.4102/hsag.v16i1.538] 7. mayosi bm, flisher aj, lalloo ug, sitas f, tollman sm, bradshaw d. health in south africa 4: the burden of non-communicable diseases in south africa. lancet 2009;374(9693):934-947. [http://dx.doi.org/10.1016/s0140-6736(09)61087-4] 8. bradshaw d, norman r, pieterse d, levitt ns. estimating the burden of disease attributable to diabetes in south africa in 2000. s afr med j 2007;97(8):700-706. 9. morris jn. exercise in the prevention of coronary heart disease: today’s best buy in public health. med sci sports exerc 1994;26(7):807. 10. anderson lh, martinson bc, crain al, et al. health care charges associated with physical inactivity, overweight, and obesity. preventing chronic disease 2005;2(4):1-12. 11. pronk np, goodman mj, o’connor pj, martinson bc. relationship between modifiable health risks and short-term health care charges. jama 1999;282(23):22352239. [http://dx.doi.org/10.1001/jama.282.23.2235] 12. katzmarzyk pt, gledhill n, shephard rj. the economic burden of physical inactivity in canada. cmaj 2000;163(11):1435-1440. 13. holtzhausen l. may news from exercise is medicine. bloemfontein: south afrian sports medicine association (sasma), 2010. http://www.sasma.org.za (accessed 29 october 2012). 14. pavey t, taylor a, fox k, et al. effect of exercise referral schemes in primary care on physical activity and improving health outcomes: systematic review and metaanalysis. bmj 2011;343:d6462. [http://dx.doi.org/10.1136/bmj.d6462] 15. lawlor da, keen s, neal rd. increasing population levels of physical activity through primary care: gps’ knowledge, attitudes and self-reported practice. fam pract 1999;16(3):250-254. [http://dx.doi.org/10.1093/fampra/16.3.250] 16. bock c, diehm c, schneider s. physical activity promotion in primary health care: results from a german physician survey. eur j gen pract 2012;18(2):86-91. [http:// dx.doi.org/10.3109/13814788.2012.675504] 17. al shehabi fa, ali nh, al-khalif gh, radwan mm. knowledge, attitudes and practices of general practitioners towards physical activity in the capital health region, kuwait. bull alex fac med 2006;42(4):933-934. 18. barrett em, darker cd, hussey j. promotion of physical activity in primary care: knowledge and practice of general practitioners and physiotherapists. j public health 2012:21(1):63-69. [http://dx.doi.org/10.1007/s10389-012-0512-0] 19. douglas f, torrance n, van teijlingen e, meloni s, kerr a. primary care staff ’s views and experiences related to routinely advising patients about physical activity: a questionnaire survey. bmc public health 2006;6(1):138. [http://dx.doi. org/10.1186/1471-2458-6-138] 20. goodwin va, richards sh, taylor rs, taylor ah, campbell jl. the effectiveness of exercise interventions for people with parkinson’s disease: a systematic review and meta-analysis. movement disorders 2008;23(5):631-640. [http://dx.doi.org/10.1002/ mds.21922] 21. white lj, dressendorfer rh. exercise and multiple sclerosis. sports medicine 2004;34(15):1077-1100. [http://dx.doi.org/0112-1642/04/0015-1077/$31.00/0] 22. graham r, dugdill l, cable n. health professionals’ perspectives in exercise referral: implications for the referral process. ergonomics 2005;48(11-14):1411-1422. [http:// dx.doi.org/10.1080/00140130500101064] 23. sallis r. developing healthcare systems to support exercise: exercise as the fifth vital sign. br j sports med 2011;45(6):473-474. [http://dx.doi.org/10.1136/ bjsm.2010.083469] http://dx.doi.org/10.1002/9780470757277.ch15] http://dx.doi.org/10.1016/s1440-2440 http://dx.doi.org/10.1016/s1440-2440 http://dx.doi.org/10.1136/bjsm.2008.054825] http://dx.doi.org/10.1249/mss.0b013e3180616b27] http://dx.doi.org/10.1249/mss.0b013e3180616b27] http://dx.doi.org/10.4102/phcfm.v4i1.346] http://dx.doi.org/10.4102/hsag.v16i1.538] http://dx.doi.org/10.1016/s0140-6736 http://dx.doi.org/10.1001/jama.282.23.2235] http://www.sasma.org.za http://dx.doi.org/10.1136/bmj.d6462] http://dx.doi.org/10.1093/fampra/16.3.250] http://dx.doi.org/10.3109/13814788.2012.675504] http://dx.doi.org/10.3109/13814788.2012.675504] http://dx.doi.org/10.1007/s10389-012-0512-0] http://dx.doi.org/10.1186/1471-2458-6-138] http://dx.doi.org/10.1186/1471-2458-6-138] http://dx.doi.org/10.1002/mds.21922] http://dx.doi.org/10.1002/mds.21922] http://dx.doi.org/0112-1642/04/0015-1077/$31.00/0] http://dx.doi.org/10.1080/00140130500101064] http://dx.doi.org/10.1080/00140130500101064] http://dx.doi.org/10.1136/bjsm.2010.083469] http://dx.doi.org/10.1136/bjsm.2010.083469] sajsm vol. 25 no. 2 2013 53 case study underlying cardiac abnormalities are the main cause of unexpected death in athletes on field. these abnormalities have been associated with a previous history of syncope, a family history of sudden cardiac arrest (sca), cardiac murmur, a history of over-exhaustion post exercise and ventricular tachyarrhythmia during physical activity. the timely diagnosis of susceptible athletes may assist with an appropriate management plan for these individuals, and allow for the prevention of premature death in sport. a young football player was screened for sca risk using the fundamental components of the pre-participation examination (ppe) – essentially, a medical history, a resting and stress electrocardiogram, and an echocardiogram to support clinical findings. the case is submitted with consideration of the applicable literature to accentuate the importance of using ppe to prevent sca in young athletes. s afr j sm 2013;25(2):53-54. doi:10.7196/sajsm.469 sudden cardiac arrest risk in young athletes p j-l gradidge,1 msc (med) (biokinetics); d constantinou,1 mb bch, bsc med (hons), ffims; l goldberg,2 md, phd, fesc 1 centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 department of cardiology, wits donald gordon medical centre, johannesburg, south africa corresponding author: p j-l gradidge (philippe.gradidge@wits.ac.za) the foremost cause of death on field in children and young athletes is sudden cardiac arrest (sca), with an increased number of cases worldwide over the past decade.[1] although sca prevalence is relatively low in the global adult athletic community (1/65 000 1/200 000), it represents a large majority (75%) of deaths during exercise. [1,2] the fédération internationale de football association (fifa) is leading the drive to ensure that the pre-participation examination (ppe) – the template of which is available on the fifa website – becomes a mandatory component of a football player’s career.[1,3] the key element in the ppe is the resting and stress electrocardiogram (ecg), which is arguably the most vital component in identifying sca risk.[1] use of the ppe would serve to avoid future sca incidences among amateur and professional football players alike. the most recent example of sca was that of the high-profile footballer, fabrice muamba, who collapsed suddenly on field at age 23 years; after cardiac arrest that lasted 78 minutes, he was resuscitated and consequently discharged from hospital several weeks later.[4] on the other hand, a medical team failed to revive italian footballer, piermario morosini, following sca.[5] these incidences of sca and sudden cardiac death (scd) could have been avoided; in the former case, by the use of ppe, and in the latter, by having adequately trained staff present on field. maron’s[6] comprehensive review on the policy regarding the prevention of unexpected mortality in hypertrophic cardiomyopathy adds valuable insight into the use of ppe as a screening tool. the emphasis of pre-competition medical assessment is on risk stratification; although it is strongly advocated by the football community worldwide, it is not always included as an essential procedure in developing african countries. the main objectives of this study were therefore to emphasise the importance of such risk stratification, using a case study focused on an asymptomatic athlete at risk of sca as an example. case a 23-year-old south african male football player, involved in amateurlevel football, was referred for examination. he was a non-smoker who had no health complaints, and claimed good effort tolerance. the individual had never experienced blackouts, typical angina or palpitations. there was no known allergy, he did not drink alcohol and he had no family history (fh) of scd. however, his mother had a history of hypertension. on examination, his general appearance was normal. he was not pale and did not show signs of clubbed fingers. neither enlargement of the thyroid gland nor signs of thyrotoxicosis were present. his jugular venous pulse was not raised. arterial pulses at all sites of examination were present and he had normal characteristics, with no delays. his heart rate (hr) in the supine position was 42 beats per min (bpm) and irregular. on the other hand, his hr in the standing position was 74 bpm and regular. his resting blood pressure was 110/68 mmhg. his first heart sound (s1) was normal and there was a short ejection systolic murmur (esm) of 1 2/6. his second heart sound (s2) occurred with physiological split. a short bruit could be heard over both the carotid arteries and abdominal aorta. his chest was clear and showed no signs of any anomaly. an abdominal examination proved unremarkable and no peripheral oedema was present. investigations and key findings resting ecg the individual’s sinus rhythm was 42 bpm; mobitz 1 (wenckebach phenomenon) 3:2 and 2:1 atrioventricular block (avb) were found in the supine position, as well as early repolarisation syndrome. an mailto:philippe.gradidge@wits.ac.za 54 sajsm vol. 25 no. 2 2013 ecg was done in the prone position, showing an hr of 74 bpm, 1st avb and mobitz 1 avb. stress ecg when undergoing an effort ecg, the participant reached peak exercise levels at the fifth stage of the bruce protocol when the test was terminated, specifically at 14:37 min of exercise, corresponding to 17.1 metabolic equivalnts. his peak hr was 193 bpm (98% of predicted maximum) and he exhibited no chest pain, ischaemic ecg changes, conduction abnormalities or early repolarisation during the exercise stress test. echocardiogram a normal-size aorta was found, with no aortic co-arctation. he had a normal 3-cusp aortic valve. the left atrium was 3.5 cm and the intraventricular septum of the left ventricle was 0.99 cm in the mid-segment. the end-diastolic dimension/end-systolic dimension was 4.9/2.9 cm and the ejection fraction was 0.72. there were no regional wall motion abnormalities. there was mild degeneration of the medial cusp of the anterior mitral valve leaflet associated with minimal mitral regurgitation. the right ventricle, right atrium and pulmonary artery, however, were normal. there was trace pulmonary regurgitation and tri cuspid regurgitation. his pulmonary arterial pressure was 21.7 mmhg. discussion examination revealed clear signs of cardiac anomalies in an otherwise asymptomatic, fit, young athlete. this 23-year-old male football player had features of athletic heart: prominent bradycardia, avb 1 2 degree (mobitz 1) and early repolarisation syndrome. there was a possible degree of atrioventricular conduction abnormalities, which is somewhat unusual; it was suggested that he should concentrate on skills development rather than on endurance training. his esm was assessed as being functional. however, in light of the aforementioned anomalies, blood tests should be conducted, including thyroid stimulating hormone, full blood count, n-terminal prob-type natriuretic peptide (nt-probnp) and iron studies. the mild mitral valve prolapse would require antibiotic prophylaxis in certain situations, such as dental procedures. the majority of documented cases of sca and scd occurred in asymptomatic athletes such as presented in this case; nevertheless, there was clear evidence of cardiac anomalies and potential risk. recently published research showed that 61% of young urban football players were at risk of sca, even though they showed no physical evidence of predisposition.[7] interestingly, some of the underlying causes of sca risk that were stressed in the study included: cardiac risk factors, such as cardiac murmur (8%); a history of fainting during sporting activity (21%); and an fh of sca (11%).[7] similarly, a survey of healthy italian young male athletes found that about 2% of the sample had underlying cardiac anomalies with the potential for future cardiac conditions.[8] the findings of these and other studies confirm that asymptomatic athletes may have hidden characteristics that could ultimately predispose the athletic population to severe cardiac events during exercise. a comprehensive ppe would enable such athletes to participate in physical activity and exercise with an awareness of the underlying abnormalities, essentially serving to evade future premature mortality on field. it the case described here, it is relevant to have the detailed evaluation of the player; should he end up with any problem, or be re-assessed, there is a point of reference for comparative purposes and to determine whether further pathology has developed. conclusion use of an ecg as an essential component of the medical assessment may result in a lower incidence of sca and consequent death in athletes. failure to perform routine ppes among athletes can have tragic consequences. we recommend that exclusive medical attention be offered to all amateur and elite athletes in all sporting codes, particularly in individuals with signs indicative of risk. the use of an ecg in the screening process alone is not sufficient to preclude sca, but should form part of a battery of tests. these would ideally prevent potential false-positive evaluation results that may initiate further superfluous assessments and tests. a cross-discipline approach to ppe in sport should be developed using the fifa approach,[1] but this needs to have a strong evidence base before implementation in nonfootball-related disciplines. references 1. kramer e, dvorak j, kloeck w. review of the management of sudden cardiac arrest on the football field. br j sports med 2010;44(8):540-545. [http://dx.doi.org/10.1136/ bjsm.2010.074526] 2. harmon kg, asif im, klossner d, drezner ja. incidence of sudden cardiac death in national collegiate athletic association athletes. circulation 2011;123:1594-1600. [http://dx.doi.org/ 10.1161/circulationaha.110.004622] 3. f-marc. fifa pre-competition medical assessment (pcma). http://fifa.com (accessed 3 april 2013). 4. redhead j, gordon j. emergencies in sports medicine. oxford: oxford university press, 2012. 5. sky news. footballer dies after collapsing on pitch. http://news.sky.com/ story/10158/footballer-dies-after-collapsing-on-pitch (accessed 3 april 2013). 6. maron bj. contemporary insights and strategies for risk stratification and prevention of sudden death in hypertrophic cardiomyopathy. circulation 2010;121:445-456. [http:// dx.doi.org/ 10.1161/circulationaha.109.878579] 7. gradidge pj, constantinou d, fiddes j, hoosain m, williams m. sudden cardiac arrest risk profiling of urban johannesburg footballers. south african journal for physical, health education, recreation and dance 2012;dec (suppl 2):247-254. 8. rizzo m, spataro a, cecchetelli c, et al. structural cardiac disease diagnosed by echocardiography in asymptomatic young male soccer players: implications for preparticipation screening. br j sports med 2012;46:371-373. [http://dx.doi.org/10.1136/ bjsm.2011.08569] http://dx.doi.org/10.1136/bjsm.2010.074526] http://dx.doi.org/10.1136/bjsm.2010.074526] http://dx.doi.org/10.1161/circulationaha.110.004622] http://fifa.com http://news.sky.com/ http://dx.doi.org/10.1161/circulationaha.109.878579] http://dx.doi.org/10.1161/circulationaha.109.878579] http://dx.doi.org/10.1136/bjsm.2011.08569] http://dx.doi.org/10.1136/bjsm.2011.08569] sajsm vol 24 no. 1 2012 27 commentary brain damage risk in diving there is a substantial body of research on the neurological and neuropsychological effects of compressed gas diving that occurs in both the recreational and occupational spheres. a recent review of diving practice indicates that there are approximately 7 million divers active worldwide, and about 500 000 training every year,1 despite the fact that it is accompanied by a number of brain-related hazards including hypoxia, gas toxicity, bubble-related insults and decompression illness (dci).* in a survey of 770 divers beckett and kordick2 indicated that half of these divers (53%) had suspected decompression symptoms. similarly, in a study of 156 air and saturation divers 51% had dci, 33% of these with neurological symptoms.3 in contrast to the high risk of dci implied by these figures, vann et al.4 suggest that if appropriate decompression procedures are followed, dci is uncommon and incidence declines. they suggest that acceptable risk for commercial diving is 0.1% for mild cases and 0.025% for serious cases; for us navy diving acceptable risk is 2% for mild cases and 0.1% for serious cases. however, these authors concede that there are insufficient data for accurate estimates of incidence of decompression sickness both in the recreational and commercial spheres, and that incidence figures based on dives made well within maximum exposure limits of accepted procedures are an underestimate of the true rates at maximum limits. notwithstanding uncertainty around the rate of occurrence of frank dci, there is growing emphasis on the fact that divers may be suffering subtle symptoms that they do not recognise as dci, and/or be suffering subclinical effects of repetitive ‘silent’ paradoxical gas embolisms that may have long-term deleterious neurological consequences.5,6 as reviewed in wilmhurst,6 neuroradiological investigations on divers predominantly provide support for brain-related changes in association with diving. a series of studies have investigated long-term/cumulative neurological and neurocognitive effects via objective psychometric testing of divers in contrast to demographically matched non-diving controls, with outcome implicating deleterious cns effects. outcomes included prolonged reaction time scores for construction divers;7 significantly poorer learning and short-term memory performance, and a tendency to sacrifice accuracy for speed for commercial abalone divers;8 and performance deficits in number of reference memory errors and navigation behaviour of construction divers.9 a cohort of divers who complained of forgetfulness were differentiated from divers without this complaint, on the basis of being significantly more impaired with regard to objective memory tests.10 further of note are studies that provide evidence for cumulative deleterious effects in association with repeat-diving. the study of aarli et al.,11 investigating for cns dysfunction, documented no significant changes in any of the professional divers immediately after one dive, but there was clear-cut impairment in a group who had performed two dives three months apart. research by vaernes et al.12 points to how repeated deep-diving activity is likely to result in greater neuropsychological impairment. it appears that, for professional divers with high exposure to decompression stress, the incidence of intellectual decline may be as high as 50%,13 and accordingly the concern is expressed that diving may produce residual intellectual decline equivalent to dementia or ‘punch-drunk syndrome’ as described in association with years of competitive participation in boxing. finally, a very recent study of military divers without a history of dci demonstrated higher motor and decision reaction times among very experienced divers logging extensive diving hours, cerebral damage in diving: taking the cue from sports concussion medicine ann b shuttleworth-edwards (phd) victoria j whitefield-alexander (phd) national sports concussion initiative, department of psychology, rhodes university, grahamstown, south africa correspondence to: ann edwards (a.edwards@ru.ac.za) abstract within the compressed gas diving arena there is a risk of cerebral damage with deleterious neuropsychological sequelae in association with decompression illness (dci), hypoxia, gas toxicity, as well as the cumulative subclinical effect of ‘silent’ paradoxical gas embolisms, the last being an area of growing concern. however, within diving medicine there is little evidence of the regular use of neuropsychological evaluation to monitor brain-related sequelae of frequent diving activity. in contrast, in recent years there has been an explosion of interest in the management of sports concussive injury, including emphasis on the pivotal role of neuropsychological evaluation within that context. taking the cue from sports concussion medicine, it is proposed that there is an urgent need to incorporate neurocognitive baseline and follow-up screening as a core component in the medical management of those involved in intensive commercial and recreational compressed air diving activities. the objective would be to facilitate (i) accurate neurodiagnostic follow-up of frank dci or an identifiable hypoxic or toxic incident; (ii) timeous identification of cumulative deleterious effects of repetitive subclinical hypoxic/toxic incidents and/or ‘silent’ paradoxical gas embolisms that might affect them in later life; and (iii) disability assessment following any such events or the combination thereof for rehabilitation and compensation purposes. *the reader is referred elsewhere for a more comprehensive delineation of the physiological mechanisms involved in injury to the nervous system in association with diving, including decompression illness, hypoxia, gas toxicity and ‘silent’ paradoxical gas embolisms, 4,5,25 which are beyond the scope of the current article. 28 sajsm vol 24 no. 1 2012 compared with less experienced military divers with significantly fewer diving hours.5 this study points to the possibility that cerebral lesions may occur after diving even without apparent dci. in essence, the neurocognitive decrements reported across the above-cited studies in association with diving participation fall broadly within the ambits of short-term memory, attentional abilities, processing speed and reaction time. parallels between cerebral injury in field contact sport and diving despite very different neuropathological underpinnings, it is apparent that from a neuropsychological perspective a number of parallels can be drawn between cerebral injury sustained via participation in a field contact sport and compressed gas diving activity. reviews indicate that the incidence of sustaining a concussion in american football or rugby union at adult level over a series of seasons is 42% and 50%, respectively.14 declines in neurocognitive function are more clearly evident when there is a history of two or more concussions and more extended periods of high-level participation in the sport, and it is commonly acknowledged that effects may go unrecognised or be subclinical, yet have cumulative deleterious longterm effects.15 finally, there is a substantial body of research that points to permanent neurocognitive consequences of concussive and cumulative subconcussive injury in association with american football, soccer, and rugby union,15 including diminished short-term memory, processing speed, reaction time, and attentional abilities. accordingly, while the incidence of concussion documented in the rugby-football sports appears considerably higher than the apparent incidence of dci under suitably controlled conditions,4 the following broad-based similarities exist between the two contexts. firstly, to a greater or lesser extent, there is known risk for the frank occurrence of a cerebrally noxious event to take place (i.e. concussion or dci) that may/may not be accompanied by persisting neuropsychological dysfunction. in both forums, albeit for different reasons, there is growing concern for ‘silent’ subclinical neurological damage in association with participation in these activities, with deleterious neurocognitive consequences. evidence for the presence of such neuropsychological dysfunction is enhanced in association with prolonged, repetitive and/or professional level participation in each of these activities. finally, the neurocognitive consequences in association with cerebral damage sustained through participation in both contact sport and diving, albeit of different neuropathological origin, are nevertheless functionally similar, falling broadly within the areas of short-term memory, attentional abilities, processing speed and reaction time. therefore, from a neuropsychological perspective, equivalent screening mechanisms for deleterious outcome due to cerebral damage that may occur in association with contact sport and diving (although neuropathogically distinct) are entirely in order. routine screening for neuropsychological impairment in divers despite the parallels that can be drawn around the occurrence and long-term outcome of neurological damage in association with concussion and diving-related brain impairment, there are marked differences in terms of how this aspect is medically managed within the two arenas. with regard to sports concussion, there has been an explosion of interest in the problem over the last decade, including the convening of three international conferences to initiate up-todate recommendations for optimal medical management of the concussive injury.16-18 one of the core guidelines to emerge from these seminal meetings is that individualised medical management of the concussed athlete is recommended including the use of neuropsychological assessment, optimally under the guidance of neuropsychologists who are considered to be ‘in the best position’ to interpret neuropsychological tests.18,19 in contrast, underwater medicine appears to be a relatively neglected area, notably in terms of neuropsychological involvement, with the main attention still being paid to emergency care of respiratory crises with neurological consequences, rather than long-term aftercare including the assessment of disability for compensation purposes.20,21 ironically, there was an international consensus conference on the long-term health effects of diving that pre-dated the first of the concussion in sport consensus conferences22 at which longitudinal follow-up of divers was recommended. however, it appears that the convening of a forum of this type out of concern for the medical management of divers in particular (rather than hyperbaric medicine more generally) was not repeated, nor did it result in the implementation of neurocognitive screening on a routine or wide basis. a comprehensive pubmed and biomed search confirms the impression that any formally stated recommendation concerning neuropsychological evaluation as a routine part of the medical examination of commercial or recreational divers has never been in place, and continues to be neglected. specific issues pertaining to neuropsychological assessment a number of neurocognitive screening programmes based on well-researched traditional neuropsychological test stimuli (i.e. having good face validity as neuropsychological instruments) have been especially developed within the sports concussion arena. these might be considered for use in the diving context, e.g. anam, headminder and impact.23 of these the impact programme, now in its fourth updated version, is the most commonly employed test of its kind worldwide, and is an hpcsaapproved test for use within south africa. the recommended mechanism within the spor ts arena is to conduct baseline neurocognitive evaluation on individuals prior to engagement in the cerebrally hazardous activity using a recognised instrument of this type for comparative purposes with follow-up testing after a cerebrally harmful event. specifically, the impact test provides an automated report on six cognitive composites that incorporate the functional areas described above that are typically implicated following the decompression event, viz. memor y function, attentional abilities, reaction time and processing speed. a strength of the impact programme is the incorporation of a 24-item check list of neuropsychiatric symptoms that are typically in evidence after concussion. recently, a special adaptation of impact has been developed for work within the militar y, keeping the neurocognitive aspect intact, but making adjustments to the demographic and symptom questionnaires. 24 similarly, for use within the diving context it would be possible to tailor-make the programme to include relevant details such as prior history of any incident of dci, years involved in diving, estimate of number of dives completed, and purpose of diving. furthermore, it would be possible to ensure that the symptom checklist incorporates neuropsychiatric sequelae that have regularly been described in association of decompression illness. symptoms following diffuse cerebral presentations such as concussion and sajsm vol 24 no. 1 2012 29 dci var y widely and are nonspecific, with many sequelae in common, such as ‘dizziness’, ‘headache’, ‘difficulty remembering’, ‘numbness’, ‘tingling’, ‘difficulty concentrating’ and ‘fatigue’. from a neuropsychological point of view, it is of prime diagnostic value to have a testee’s idiosyncratic self-report symptom profile, in addition to the objective psychometric test profile, when drawing conclusions concerning the presence or absence of neurological fall-out and/or the extent of disability. conclusions as a matter of some urgency, it would seem appropriate for diving medicine to consider taking the cue from sports concussion medicine, specifically with regard to the incorporation of neuropsychological evaluation (such as is widely applied within professional and amateur contact sports) to monitor its cerebrally hazardous injury. ideally, this would involve the initiation of computerised neurocognitive baseline screening, and follow-up testing in the wake of any dci incident, as well as other identifiable hypoxic or toxic respiratory incidents, to establish the extent of disability. importantly, comparative baseline screening for divers on an annual or a bi-annual basis would provide the platform to establish the presence of ‘silent’ cognitive decline implicating the insidious onset of brain dysfunction that may affect them in the long term, such as may not be immediately in the diver’s awareness or apparent during a regular medical examination. as dci appears to be a relatively uncommon and declining occurrence, especially when under controlled conditions (compared with the incidence of the concussive incident in contact sport), the initiation of routine neurocognitive baseline testing in all contexts might be deemed to be unwarranted. nevertheless, it is still a distinct risk, and taken together with the growing concern for subclinical neuropathological changes due to paradoxical gas embolisms, such testing would appear to be the advised route to follow for those involved in recurrent compressed gas diving activity. at the very least, the implementation of longitudinal studies of both occupational and recreational divers utilising computerised neurocognitive testing with a tool such as impact is indicated, to capture immediate and enduring neuropsychological outcome of both clearly identifiable as well as ‘silent’ neuropathological events. acknowledgements this article is based on a paper presented by invitation at the 17th international congress of hyperbaric medicine (ichm), cape town convention centre, cape town, south africa, 16 19 march 2011. funding for costs involved in the preparation and earlier presentation of this review was facilitated by national research fund (nrf) incentive funding, and a rhodes university joint research council (jrc) grant. declaration of conflict of interests the authors are involved in implementing the impact programme in south africa and the uk for research and clinical purposes. references 1. levett d, millar i. bubble trouble: a review of diving physiology and disease. postgrad med j 2008;84(997):571-578. 2. beckett a, kordick m. risk factors for dive injury: a survey study. research in sports medicine 2007;(15):3-201. 3. todnem k, nyland h, kambestad b, aarli j. influence of occupational diving upon the nervous system: an epidemiological study. british journal of industrial medicine 1990;47(708):714. 4. vann r, butler f, mitchell s, moon r. decompression illness. lancet 2011;377(9760):153-164. 5. kowalski j, varn a, rottger s, et al. neuropsychological deficits in scuba divers: an exploratory investigation. undersea hyperbaric medicine 2011;38(3):197-204. 6. wilmhurst p. brain damage in divers. bmj 1997;314(7082):689-690. 7. bast-pettersen r. long-term neuropsychological effects in non-saturation construction divers. aviation space and environmental medicine 1999;70(1):51-57. 8. williamson a, clarke b, edmonds c. the influence of diving variables on perceptual and cognitive functions in professional shallow-water (abalone) divers. environ res 1989;50(1):93-102. 9. leplow b, tetzlaff k, holl d, zeng l, reuter m. spatial orientation in contruction divers are there associations with diving experience? int arch occup environ health 2001;74(3):189-198. 10. taylor c, macdiarmid j, ross j, et al. objective neuropsychological test performance of professional divers reporting a subjective complaint of “forgetfulness or loss of concentration”. scand j work, environ health 2006;32(4):310-317. 11. aarli j, vaernes r, brubakk a, nyland h, skeidsvoll h, tonjum s. central nervous dysfunction associated with deep-sea diving. acta neurol scand 1985;71(1):2-10. 12. vaernes r, klove h, ellertsen b. neuropsychologic effects of saturation diving. undersea biomedical research 1989;16(3):233-251. 13. edmonds c, boughton j. intellectual deterioration with excessive diving (punch drunk divers). undersea biomedical research 1985;12(3):321-326. 14. shuttleworth-edwards ab, noakes td, radloff se, et al. the comparative incidence of reported concussions for follow-up management in south african rugby union. clin j sport med 2008;18(5):403-409. 15. shuttleworth-edwards ab, whitefield vj. ethically we can no longer sit on the fence: a neuropsychological perspective on the cerebrally hazardous contact sports. south african journal of sports medicine 2007;19(2):32-38. 16. aubry m, cantu r, dvorak j, et al. summary and agreement statement of the 1st international symposium on concussion in sport, vienna, 2001. clin j sport med 2002;12(1):6-11. 17. mccrory p, johnston k, meeuwisse w, et al. summary and agreement statement of the 2nd international conference on concussion in sport, prague, 2004. clin j sport med 2005;15(2):48-55. 18. mccrory p, meeuwisse w, johnston k, et al. consensus statement on concussion in sport: the 3rd international conference on concussion in sport, zurich, november 2008. br j sports med 2009;43:i76-i84. 19. schatz p, moser rs. current issues in pediatric sports concussion. the clinical neuropsychologist 2011;25(6):1042-1057. 20. braatvedt g, mathew bg, corrall r. underwater medicine: a neglected area in accident and emergency specialist training. br j sports med 1991;25(2):102-103. 21. rozali a, khairuddin h, sherina m, zin b, sulaiman a. decompression illness secondary to occupational diving: recommended management based current legislation and practice in malaysia. med j malaysia 2008;63(2):166-169. 22. hope a, lund t, elliot d, halsey m, wiig h. long term health effects of diving. an international consensus conference, godoysund, norway, 6 10 june 1993. bergen: norwegian underwater technology centre/university of bergen, 1994. 23. guskiewicz km, bruce de, cantu rc, et al. national athletic trainers’ association position statement: management of sport-related concussion. journal of athletic training 2004;39:280-297. 24. lovell mr, collins m, pardini je, parodi a, yates a. management of cerebral concussion in military personnel: lessons learned from sports medicine. operative techniques in sports medicine 2005;13:212-221. 25. lishman w. organic psychiatry: the psychological consequences of cerebral disorder. 3rd ed. oxford, uk: blackwell science ltd., 1999. sajsm 376.indd original research sajsm vol. 25 no. 3 2013 63 background. medial tibial stress syndrome (mtss) is the most common lower-leg injury in athletes, and is thought to be caused by bony overload. to prevent mtss, both pathophysiological and aetiological factors specific to mtss need to be identified. the intrinsic risk factors that contribute to the development of mtss are still uncertain. objective. to determine the intrinsic risk factors of mtss by sampling a large population of athletic mtss patients and controls. methods. athletes with mtss and control subjects were medically examined in terms of range of motion of the leg joints (hip abduction, adduction, internal and external range of motion; ankle plantar and dorsal flexion; hallux extension and flexion; subtalar inversion and eversion), measures of over-pronation and maximal calf girth. results. ninety-seven subjects agreed to participate in the study: 48 mtss patients and 49 active controls. the following variables were considered: gender, age, body mass index (bmi), hip abduction, hip adduction, internal and external hip range of rotation, ankle plantar and dorsal flexion, hallux flexion and extension, subtalar inversion and eversion, maximal calf girth, standing foot angle and navicular drop test. in multivariate logistic regression analysis, hip abduction (odds ratio (or) 0.82; 95% confidence interval (ci) 0.72 0.94), ankle plantar flexion (or 0.73; 95% ci 0.61 0.87) and subtalar inversion (or 1.24; 95% ci 1.10 1.41) were significantly associated with mtss. the nagelkerke r2 for this model was 0.76, indicating that 76% of the variance in the presence of mtss could be explained by these variables. conclusion. decreased hip abduction, decreased ankle plantar flexion and an increased subtalar inversion could be considered risk factors for mtss. s afr j sm 2013;25(3):63-67. doi:10.7196/sajsm.376 intrinsic factors associated with medial tibial stress syndrome in athletes: a large case-control study m winters,1 msc; h veldt,2 md; e w bakker,3,4 phd; m h moen,5,6 md, phd 1 university medical centre utrecht, department of rehabilitation, nursing science and sport, utrecht, the netherlands 2 rijnland medical centre, orthopedic department, leiderdorp, the netherlands 3 department of clinical epidemiology, biostatistics and bioinformatics, university of amsterdam, the netherlands 4 kbc haaglanden, the hague, the netherlands 5 bergman clinics, naarden, the netherlands 6 sports physician group, saint lucas andreas hospital, amsterdam, the netherlands corresponding author: m winters (marinuswinters@hotmail.com) medial tibial stress syndrome (mtss) is the most frequently seen overuse injury in the lower leg in jumping and running athletes.[1] commonly mtss is defined as 'exercise induced pain on the posteromedial border of the tibia’ plus the presence of ‘pain on palpation along the posteromedial border over five or more consecutive centimetres'.[2] until now, no effective strategies aimed at the prevention of mtss have been described in athletic populations.[3] for prevention, knowledge of the pathophysiological and aetiological risk factors specific to mtss is essential. regarding pathophysiology, mtss is thought to be a bony overload injury.[3] the most firm evidence for this is derived from a case control study, which showed that local bone-mineral density was decreased in mtss patients. a follow-up study concluded that bone-mineral density was restored when patients had recovered, confirming that the bony overload theory was likely.[4] regarding aetiological factors, several studies have been conducted. however, the intrinsic factors that contribute to the onset of mtss are still uncertain, since many studies have contradictory results. female gender, a high body mass index (bmi) and foot pronation were shown to be associated with mtss in several studies.[3] in addition to these factors, other possible risk factors for mtss have been studied as well, but mostly in small army populations;[2,5-7] consequently, the results may be not applicable to athletic populations. furthermore, the results of risk-factor studies are often conflicting. this may be the result of the variety of factors assessed and the small samples studied. the aim of this study was to determine the intrinsic risk factors for mtss by sampling a large population of athletic mtss patients and controls. with a better understanding of the risk factors for mtss, the prevention of the syndrome by targeting of these risk factors becomes more feasible. methods subjects and procedure subjects with mtss were recruited at the sports medical department of the rijnland medical centre when they signed up for treatment. to facilitate patient recruitment, local physiotherapists and general practitioners in the hospital area were informed about the study telephonically and by email. healthy athletic control subjects (aged ≥16 years) were recruited at the central institute of education for sports instructors (cios) in haarlem and the hague academy for physical education (halo) in the hague. one teacher at each location informed 64 sajsm vol. 25 no. 3 2013 all first-year students about the study and asked them to participate voluntarily. on average, the athletic controls performed approximately 15 hours of sports activities per week at school (mainly jumping and running activities). the athletic controls were free of mtss symptoms (leg pain during exercise) upon assessment. controls were excluded if they were not able to perform physical activity in the 6 months prior to the study’s start. mtss was defined as 'exercise induced pain along the posteromedial border' plus the presence of 'pain on palpation along the posteromedial border of the tibia over a length of five or more centimetres'.[2] patients (age ≥16 years) with mtss complaints persisting for longer than 2 weeks were included in the study when no tibial stress fracture or chronic exertional compartment syndrome (cecs) was suspected based on clinical examination. pain in tibial stress fractures is often focal, whereas pain in mtss is more diffuse. furthermore, in contrast with mtss, pain in tibial stress fractures is usually characterised by a sudden onset. patients with cecs usually indicate a burning, cramping pain over the involved compartment. pain increases with continued exercise and ceases after exercise.[8] patients with a history of lower-leg or foot fractures and patients who previously had surgery on the legs and feet were excluded. all participants signed informed consent. the local medical ethics committee approved the study prior to its commencement. demographic information and physical examination two sports physicians obtained the participants’ demographic information using a standardised form. gender (male/female), age (years), body weight (kg) and body length (cm) were recorded. the medical examination was conducted according to moen et al.[5] one sports physician performed the standardised physical exami nation in the test group with mtss, whereas the other performed this in the control group. a goniometer was used to assess articular range of motion (zimmer ltd., swindon, uk). this method has a good inter-observer reliability.[9,10] prior to this examination, several familiarisation sessions were held to minimise inter-observer error. the different parameters were examined as follows: • hip abduction and adduction ranges of motion were measured with the patient supine and with the knee extended and the hip in neutral position. the stationary arm was aligned vertically with the body, and the movable arm was aligned with the basis of the patella. the hip was then moved until the pelvis tilted or declined on the ipsilateral side, for hip abduction and adduction, respectively.[11] • hip internal and external ranges of motion were measured with the patient supine and the knee and hip flexed to 90°. the hip was internally and externally rotated to a firm end feel. range of motion, relative to the initial position was measured in degrees.[6] • ankle dorsal and plantar flexion ranges of motion were measured with the subject in the prone position, with the knees extended and the ankles hanging over the edge of the table. the measurement was obtained with the axis of the goniometer on the lateral malleolus. the stationary arm was aligned with the head of the fibula and the movable arm was aligned with the fifth metatarsal. the investigator passively dorsiflexed and plantar flexed the foot until tension was noticed.[9] • hallux extension and flexion were measured with the goniometer until tension was felt, with the subject in a supine position and the knees extended. the movable arm was aligned with the hallux and the stationary arm was aligned with the first metatarsal bone.[10] • subtalar eversion and inversion of the ankle were assessed with the subject supine and the knees extended. with the subtalar joint in neutral stance, an inclinometer was placed perpendicular to the foot over the posterior aspect of the calcaneus. maximal inversion and eversion were measured from this position.[10] • maximal calf girth was measured (in cm) with the subject standing relaxed and upright. a measuring tape was used to obtain the maximum girth of the relaxed calf.[12] • the standing foot angle was measured according to sommer and vallentyne.[13] with the subject standing, the angle between the first metatarsal, medial malleolus and the navicular bone was measured. results were dichotomised to ≥140° and <140°. this cut-off was used because it had the best sensitivity and specificity (71% and 70%, respectively).[13] • the navicular drop test was performed after marking the navicular prominence with the subject sitting in a chair and the feet on the ground (non-weight-bearing) in neutral subtalar position. the distance from the prominence to the floor was then measured. the test was repeated with the subject standing on both feet, shoulderwidth apart (weight-bearing). the two measurements were subtracted, resulting in a difference score (in cm). the results were dichotomised (<0.5 cm and >0.5 cm) according to bennett et al.[7] data analysis data analysis was performed by two of the investigators (mw and eb) using spss version 20.0. demographic and intrinsic risk factors were presented in terms of means with standard deviations (sds) for continuous data. in the case of skewed distributions, medians and ranges were presented. nominal data were presented with their percentages. differences between the groups were assessed using student’s t-test, or when the assumptions were violated, the mann-whitney u-test for continuous variables and chi-square test for nominal data. logistic regression was used to assess the association between the dependent (mtss yes/no) and independent variables. after univariate analysis, a multivariate logistic regression analysis (backward wald) was conducted on those independent variables that showed a relation to the presence of mtss. considering the number of subjects included in this study, we limited the amount of variables in the multivariate model to 9. threshold for entry of independent variables in the multivariate model was p<0.1 and for removal, p>0.2. when more than 9 variables showed a possible relationship with mtss in univariate analysis, a threshold of p<0.05 was used. the nagelkerke r2 was used to assess the explained variance of the model. results in total, 97 subjects (table 1) agreed to participate in the study: 48 mtss patients and 49 active controls. gender, age, body mass index (bmi), decreased hip abduction, increased hip adduction, increased ankle plantar and dorsal flexion, decreased hallux flexion, increased subtalar inversion and eversion and maximal calf girth were significantly different between the groups (table 1). after univariate analysis, 9 variables – gender, age, bmi, hip abduction and adduction, ankle plantar flexion, subtalar inversion sajsm vol. 25 no. 3 2013 65 table 1. intrinsic factors and differences between mtss patients and active controls* risk factors mtss group (n=48) control group (n=49) p-value women, n (%) 27 (56.3) 16 (32.7) 0.02 age in years, mean (±sd) 20.90 (±4.34) 18.33 (±3.51) <0.01 bmi, mean (±sd) 22.39 (±2.12) 21.29 (±2.12) 0.02 hip abduction, mean (±sd) 51.15 (±7.94) 60.00 (±7.00) <0.01 hip adduction, mean (±sd) 35.00 (±9.78) 29.49 (±3.85) <0.01 hip internal rotation (°), mean (±sd) 45.00 (±10.21) 45.71 (±5.30) 0.67 hip external rotation (°), mean (±sd) 43.54 (±8.31) 43.57 (±4.89) 0.98 ankle dorsal flexion (°), mean (±sd) 20.61 (±7.19) 18.59 (±4.12) 0.10 ankle plantar flexion (°), mean (±sd) 45.11 (±8.66) 53.06 (±5.76) <0.01 hallux flexion, mean (±sd) 34.81 (±8.26) 37.96 (±5.49) 0.03 hallux extension, mean (±sd) 55.95 (±12.81) 57.86 (±8.90) 0.41 subtalar inversion, mean (±sd) 33.44 (±8.91) 28.27 (±4.95) <0.01 subtalar eversion, mean (±sd) 20.78 (±7.68) 18.16 (±3.01) 0.03 maximal calf girth, mean (±sd) 37.14 (±2.21) 35.89 (±2.17) 0.01 standing foot angle >140°, n (%) 26 (54.1) 34 (69.3) 0.21 navicular drop test >0.5 cm, n (%) 25 (52.1) 22 (44.9) 0.41 sd = standard deviation; bmi = body mass index (weight in kg ÷ height in m2). * differences between groups were assessed using students t-test, or when the assumptions were violated, the mann-whitney u-test for continuous variables and chi-square test for nominal data. obtained p-values are presented. table 2. univariate and multivariate logistic regression analysis for mtss risk factors parameters univariate logistic regression multivariate logistic regression or (95% ci)or (95% ci) p-value gender (female) 2.65 (1.16 6.06) 0.02* 6.11 (0.90 41.61) age 1.21 (1.06 1.39) < 0.01* 0.99 (0.89 1.09) bmi 1.28 (1.05 1.57) 0.02* 1.39 (0.99 1.97) hip abduction 0.85 (0.79 0.91) <0.01* 0.82 (0.72 0.94)† hip adduction 1.12 (1.04 1.20) <0.01* 1.05 (0.92 1.19) hip internal rotation 0.99 (0.94 1.04) 0.66 hip external rotation 1.00 (0.94 1.06) 0.98 ankle dorsal flexion 1.07 (1.00 1.16) 0.11 ankle plantar flexion 0.85 (0.78 0.92) <0.01* 0.73 (0.61 0.87)† hallux flexion 0.93 (0.87 1.00) 0.04 hallux extension 0.98 (0.95 1.02) 0.40 subtalar inversion 1.11 (1.04 1.19) <0.01* 1.24 (1.10 1.41)† subtalar eversion 1.10 (1.00 1.20) 0.03* 0.99 (0.86 1.14) maximal calf girth 1.30 (1.06 1.60 0.01* 1.22 (0.74 1.99) standing foot angle >140° 0.56 (0.23 1.39) 0.21 navicular drop test 0.71 (0.32 1.61) 0.41 or = odds ratio; ci = confidence interval; bmi = body mass index. * parameters with a relationship with mtss after univariate regression analysis and which were entered into the multivariate model (p<0.1). † significantly associated with mtss after multivariate regression analysis (p<0.05). 66 sajsm vol. 25 no. 3 2013 and eversion, and maximal calf girth – were eligible for selection into the multivariate model (p<0.1). in the multivariate model, reduced hip abduction, ankle plantar flexion and increased mobility of subtalar inversion were significantly associated with mtss and could therefore be considered risks factor for mtss (table 2). all parameters were measured on a continuous scale. for hip abduction, the odds ratio (or) for mtss decreased by a factor of 0.82 for each additional degree of hip abduction. consequently, for every additional 5° difference in range of motion, the odds for mtss decreased by a factor of 0.37 (0.825). for ankle plantar flexion, an or of 0.73 was found. for two subjects with a difference of 5° in plantar flexion of the ankle, the odds for mtss would be 0.21 (0.735). in contrast, with every additional degree in subtalar inversion, the odds for mtss increased by a factor of 1.24; therefore, with a 5 cm increase in subtalar inversion, the odds for mtss were 2.93 (1.245). the percentage of the total log likelihood for mtss explained by the significant independent variables (i.e. hip abduction, ankle plantar flexion and subtalar inversion) was 76.7% (nagelkerke r2). discussion this is the largest study assessing intrinsic factors (gender, age, bmi, hip adduction, hip abduction, hip internal range of motion, hip external range of motion, ankle dorsal flexion, ankle plantar flexion, hallux flexion, hallux extension, subtalar inversion, subtalar eversion, maximal calf girth, standing foot angle, navicular drop test) of mtss in athletes. following multivariate logistic regression analysis, hip abduction, ankle plantar flexion and subtalar inversion were associated with mtss, explaining 76% of the variance in the presence of mtss. this is the first study to conclude that hip abduction is associated with mtss. the mean hip abduction was 51° in athletes with mtss, and 60° in athletes without mtss. decreased hip abduction is also considered a risk factor for mtss. in contrast to previous findings, we did not find differences in hip internal rotation between the groups (p>0.05). the mechanisms through which hip range of motion affect loading on the tibia are unclear. burne et al.[6] hypothesised that alterations in hip range of motion cause stride patterns that could increase loading of the posteromedial side of the tibia. we found increased subtalar inversion to be significantly associated with mtss. this was previously found by viitasalo and kvist.[14] in the study by hubbard et al.,[15] no significant difference in subtalar inversion was found between those who developed mtss and those who did not. the mean ankle plantar flexion range of motion was 45° in athletes with mtss and 53° in athletes without mtss. this is in contrast to previous studies that found a higher ankle plantar flexion range of motion to be a risk factor for mtss.[5,15] moen et al.[5] speculated that an increased plantar flexion range of motion leads to more forefoot running, leading to more loading on the tibia. our results oppose this suggestion. in this study, cases and controls differed significantly in terms of gender and bmi. gender and bmi were non-significant (both p=0.06) in the multivariate regression analysis. this supports hubbard et al.’s[5] conclusion. in contrast, plisky et al.[16] and bennett et al.[7] found that women have a higher chance of developing mtss. therefore, whether or not gender is a risk factor for mtss remains unclear. various studies have shown that over-pronation is a risk factor for tibial stress injuries.[3] this study, however, suggests that over-pronation during stance is not an important factor in mtss development (p>0.05). these results concur with the studies by hubbard et al.[15] and plisky et al.[16] future studies are warranted in which athletes with excessive pronation and without complaints are provided with an antipronation inlay with the aim of preventing mtss. we chose to assess static instead of dynamic parameters, as it is more practical for a clinician to assess static risk factors in, e.g., an outer clinic. we have completed another study that assessed dynamic parameters (moen et al., unpublished data 2013); however, the data have not been presented here. in the study, it became apparent that measuring dynamic parameters was time-consuming and difficult to perform, and consequently not practical for clinicians. study limitiations this study had several limitations. firstly, we did not measure the volume and intensity of exercise across groups; however, it is unlikely that exercise confounded the relationship between the mentioned intrinsic factors and mtss. the athletic controls were students who performed approximately 15 hours of running and jumping sports activities per week. we know that the patients endured similar exercise volumes and intensities. secondly, both groups were examined by two different observers; despite this, the inter-observer reliability was found to be fair for these measurements. thirdly, the sports physicians were not blinded to whether the subjects were test cases or controls. one of the results could possibly have been the result of chance. we allowed 9 variables in the multivariate model. some experts advise to impute one parameter for each subject, others for each case. in conclusion, the study results need to be interpreted with caution. further research focused on intrinsic factors is required before hard conclusions can be drawn. as part of the prevention of mtss, trainers, physicians and therapists should assess athletes’ hip abduction, ankle plantar flexion and subtalar inversion prior to commencing a training regime, to detect abnormalities that could lead to the onset of mtss. conclusion we assessed intrinsic risk factors for mtss in a large population of athletic mtss patients, and found that a decreased hip abduction, ankle plantar flexion and an increased subtalar inversion could be considered such. references 1. taunton je, ryan mb, clement db, et al. a retrospective case-control analysis of 2002 running injuries. br j sports med 2002;36(2):95-101. [http://dx.doi.org/10.1136/ bjsm.36.2.95] 2. yates b, white s. the incidence and risk factors in the development of medial tibial stress syndrome among naval recruits. am j sports med 2004;32(3):772-780. [http:// dx.doi.org/10.1177/0095399703258776] 3. moen mh, tol jl, weir a, steunebrink m, de winter tc. medial tibial stress syndrome: a critical review. sports med 2009:39(7):523-546. [http://dx.doi. org/10.2165/00007256-200939070-00002] 4. magnusson hi, ahlborg hg, karlsson c, nyquist f, karlsson mk. low regional tibial bone density in athletes with medial tibial stress syndrome normalizes after recovery from symptoms. am j sports med 2003;31(4):596-600. sajsm vol. 25 no. 3 2013 67 5. moen mh, bongers t, bakker ew, et al. risk factors and prognostic indicators for medial tibial stress syndrome. scan j med sci sports 2012;22(1):34-39. [http://dx.doi. org/10.1111/j.1600-0838.2010.01144.x] 6. burne sg, khan km, boudville pb, et al. risk factors associated with exertional tibial pain: a twelve months prospective clinical study. br j sports med 2004:38(4):441-445. [http://dx.doi.org/10.1136/bjsm.2002.004499] 7. bennett je, reinking mf, pluemer b, et al. factors contributing to the development of medial tibial stress syndrome in high school runners. j orthop sports phys ther 2001:31(9):504-510. 8. edwards ph jr, wright ml, hartman jf. a practical approach for the differential diagnosis of chronic leg pain in the athlete. am j sports med 2005;33(8):1241-1249. [http://dx.doi.org/10.1177/0363546505278305] 9. jonson sr, gross mt. intraexaminer reliability, interexaminer reliability and mean values for nine lower extremity skeletal measures in healthy naval midshipmen. j orthop sports phys ther 1997:25(4):253-263. 10. gheluwe van b, kirby ak, roosen p, phillips rd. reliability and accuracy of biomechanical measurements of the lower extremity. j am podiatr med assoc 2002:92(6):317-326. 11. prather h, harris-hayes m, hunt dm, steger-may k, mathew v, clohisy jc. reliability and agreement of hip range of motion and provocative physical examination tests in asymptomatic volunteers. pm&r 2010;2(10):888-895. [http://dx.doi.org/10.1016/j. pmrj.2010.05.005] 12. zatsiorsky v, seluyanov v, cugunova l. in vivo body segment inertial parameters determination using a gamma-scanner method. in: berme b, capozzo a, eds. biomechanics of human motion: applications in rehabilitation, sports and ergonomics. worthington, oh: betec corporation, 1990:186-202. 13. sommer hm, vallentyne sw. effect of foot posture on the incidence of medial tibial stress syndrome. med sci sports exerc 1995:27(6):800-804. 14. viitasalo jt, kvist m. some biomechanical aspects of the foot and ankle in athletes with and without shin splints. am j sports med 1989;11(3):125-130. [http://dx.doi. org/10.1177/036354658301100304] 15. hubbard tj, carpenter em, cordova ml. contributing factors to medial tibial stress syndrome: a prospective investigation. med sci sports exer 2009:41(3):490-496. 16. plisky ms, rauh mj, heiderscheit b, underwood fb, tank rt. medial tibial stress syndrome in high school cross-country runners: incidence and risk factors. j orthop sports phys ther 2007:37(2):40-47. [http://dx.doi.org/10.2519/jospt.2007.2343] pg80-83.indd introduction diving is a popular sport despite the high risks involved. 1 the sport allows children and adults to obtain the first level of qualification, a junior dive certificate for children and an open water certificate for adults. 2 the social aspect of this sport is evident as there are a large number of divers worldwide. 2 the professional association of diving instructors (padi) and the national association of underwater instructors (naui) have the largest recreational diving membership and diver training organisation. 3 these associations were originally only available to the usa, but the popularity of the sport required the expansion to the rest of the world. according to these associations it is mandatory for all potential scuba divers to complete a medical examination and a questionnaire prior to beginning the course. 4 the medical examination must include ear history of the potential dive student. 5 there are several factors concerning the ears that would disqualify a diver from continuing with the sport. these factors include perforated eardrums, surgery to the ear, chronic or acute otitis media, equalising problems, vestibular dysfunction and hearing loss. 6 in scuba diving the ear is the vital organ responsible for the equalisation of pressure during ascent and descent between ambient water pressure and the external auditory canal, middle ear and paranasal sinuses. 7 failure to equalise correctly may result in pain and rupture of the occluded space, with disabling and possible lethal consequences. 8 previously ruptured but healed round or oval window membranes are at an increased risk of rupture due to failure to equalise pressure or due to marked over-pressurisation during vigorous or explosive valsalva manoeuvres. 2 the analysis and decision concerning a prospective diver’s medical suitability rests with the examining physician. 5 however, it is the responsibility of the diver to provide accurate information concerning his/her earrelated history. subsequent to the clearance from the physician, the prospective diver is allowed to begin the diving course. according to du plessis et al. middle-ear barotrauma (mebt) is the most common medical complication in diving. exposure to the underwater environment is associated with several unique disorders, such as ear decompression sickness and barotraumas that may require recompression in a hyperbaric chamber. 9 increasing pressure during descent reduces the volume of the paranasal sinuses and middle ear which, if not properly equalised, will sustain injury due to barotraumas. 11 the greatest volume change occurs between zero and 10 metres of the dive; 2 at this depth every diver is exposed to possible damage of the audiological system. divers will need to dive to depths of approximately 45 metres to equal the total volume change produced during the first 10 metres of descent, 12 indicating why most diving injuries occur during shallow dives. 13 modern recreational scuba divers perform multiple dives, 14 therefore increasing the risk of damage to the auditory system. literature suggests that there are implications of scuba diving for the auditory system. however, there is a gap in the information regarding the divers’ knowledge about these implications. the main objective of this study was to bridge that gap and consequently determine the way forward to reduce the audiological effects of diving on the growing number of recreational scuba divers in south africa. the general aim of the study was to determine the knowledge of recreational scuba original research recreational scuba divers’ knowledge regarding the audiological consequences of the sport abstract background: the sport of scuba diving may be associated with possible injuries, especially those concerning the auditory system. research available focuses on the implications of recreational scuba diving on the auditory system. however, there is a lack of information regarding the knowledge of recreational scuba divers with regard to the audiological consequences of this sport. method: the aim of this study was to determine whether scuba divers have knowledge pertaining to the consequences of the sport on the auditory system. thirty-five participants were purposefully selected; their qualifications ranged from an open water diver to a course director. a mixed-method design was implemented in this study with the use of a questionnaire. results: forty per cent of the participants were given only the basic medical clearance form to complete; the full medical pack was not made available. however, 97% of the participants signed the medical clearance. one participant did not know that a medical clearance form was required. there were 82% of the participants who had audiological complications subsequent to diving; these individuals did not seek help from an audiologist and continued to dive. conclusion: there is a need for awareness regarding the effects of diving on the auditory system as participants in this study were not fully aware of the risks of the sport in relation to the ear. the results suggest that participants who experience ear difficulties after dives,do not have sufficient knowledge regarding the ear and the professional who is qualified to assess and manage the difficulties. correspondence: dhanashree pillay speech pathology & audiology private bag 3 2050 wits tel: 011 717-4581 e-mail: dhanashree.pillay@wits.ac.za dhanashree pillay (m communication pathology) nastasha p jardine (final-year student) university of the witwatersrand, johannesburg 80 sajsm vol 22 no. 4 2010 divers with regard to the auditory effects of the sport. the specifi c aims of the study were to determine: • whether recreational scuba divers read the medical clearance package prior to the scuba divers’ course, paying special attention to the information provided on the ear • whether recreational scuba divers understand the correct procedure for equalising their ears • whether the recreational diver is aware of the implications of not equalising the ear correctly • what precautions are taken by recreational scuba divers to protect their ears, prior to diving • whether the recreational scuba diver presents with audiological abnormalities related to diving, i.e. tinnitus, sensorineural hearing loss, vertigo and barotrauma • the actions of a recreational diver, should they experience an audiological abnormality, after diving. methodology research design a mixed-method design was implemented in this research study. the qualitative aspect of the study offered a participant the freedom to express his or her thoughts, feelings and experiences. 15 the quantitative facet was used to analyse the data obtained in the closedended sections of the questionnaire. 16 description of participants participants were selected from dive schools within the gauteng region using purposeful sampling 17 to ensure that the individuals met the selection criteria. thirty-fi ve divers responded to the study. a breakdown of the participants’ age is given in table i. the participants had a range of dive qualifi cations as shown in table ii. there were 10 participants who had a masters qualifi cation or higher. inclusion criteria the criteria were the following: • the participant needed to be 18 years or older. • the participant needed to have the open water diver certifi cate as the minimum diving qualifi cation. • the participant may not have any medical qualifi cation or allied medical qualifi cation regarding the ear, nose or throat. all participants within this study met all three requirements. procedure the researcher used a self-constructed questionnaire. open and closed format questions were utilised 18 as it provided unprompted opinions from the participants, particularly as each participant had their own responses based on personal experience and level of qualifi cation and training, thereby achieving a variety of responses that were broad and thus truly refl ected the opinions of each participant. 19 data analysis descriptive statistics were used to present the qualitative information obtained, therefore describing the behaviour of a subject without infl uencing it in any way. 18 ethical consideration this study was approved by the human research non-medical ethics committee at the university of the witwatersrand. each participant had the opportunity to carefully consider the risks and benefi ts of participating in the study. 20 all participants completed the consent form. results and discussion results obtained are discussed in terms of the sub-aims of the study. sub-aim (i): to determine whether recreational scuba divers read the medical clearance package prior to the scuba divers’ course forty eight per cent of participants were informed verbally, by their dive instructors, about the medical clearance package. however, 40% of participants were given only the basic medical sheets that required a signature. sixty per cent of participants were given the entire medical package to read and complete. the medical pack is utilised to determine if a doctor should examine the learner diver before participating in the recreational sport. the medical pack consists of a questionnaire pertaining to medical pathologies that may provide a contraindication prior to the dive. 21 twenty per cent of the participants completed the informed consent required despite not reading the information from the medical info pack as it was not deemed imperative to the dive. five per cent of the participants indicated that they did not complete their own medical information and 17% just fi lled out the sheets wherever they were told to. one participant did not know that a medical clearance was required thus did not give formal consent to participate in the sport. hence this participant started the course with inadequate knowledge of the risks associated with the sport. these table i. age distribution of participants age range of participants number of female participants number of male participants 15 19 years 1 4 20 24 years 5 6 25 29 years 3 4 30 34 years 2 2 35 39 years 0 1 40 44 years 2 3 45 49 years 0 1 50 54 years 0 1 table ii. qualifi cation of participants level of qualifi cation male participants female participants total open water 3 4 7 adventure diver 1 1 2 advanced open water 4 3 7 rescue diver 7 2 9 master scuba diver 5 3 8 master instructor 1 0 1 course director 1 0 1 total 22 13 35 sajsm vol 22 no. 4 2010 81 82 sajsm vol 19 no. 4 2007 results indicate that a large percentage of scuba divers in this study were not fully aware of the specifi c risks associated with the sport as depicted in the medical pack. 22 it is essential for the dive school to obtain the medical clearance forms to ensure that the individual is fi t to dive and the individual has granted permission to participate in the sport with full knowledge of the risks involved. 23 sub-aim (ii): to determine whether recreational scuba divers understand the correct procedure of equalising their ears all 35 participants were aware of the correct procedure when equalising their ears. all participants presented with similar answers when explaining the correct procedure for the equalisation process by pinching the nose closed and blowing gently to relieve the ear cavity of the pressure. 7 the scuba diver who is not practising the correct equalisation methods is at risk of developing a burst tympanic membrane, bleeding ears, dizziness, nausea and pain. 24 sub-aim (iii): to determine whether the recreational diver is aware of the implications of not equalising the ear correctly each participant highlighted at least one negative implication placed on the auditory system if not correctly equalised. table iii illustrates the negative implications selected by the participants. excessive force caused by increased water pressure during a dive can cause permanent damage to the ears, 7 therefore divers need to be fully aware of the negative aspects of the sport. sixty eight per cent of participants indicated a burst eardrum as a consequence of the sport while 25% stated barotrauma as a consequence. sub-aim (iv): to determine what precautions are taken by recreational scuba divers to protect their ears prior to diving hearing assessments eighty-eight per cent of the participants did not have a hearing test before they began scuba diving as they did not feel it essential. eleven per cent of the participants had consulted an audiologist in the past but the reason for referral was not related to the scuba diving. additional precautionary measures forty-six per cent of participants indicated that no precautionary measures are required as protection of the ear was not necessary. fourteen per cent of the participants indicated their frequent use of ear buds to protect their ears. eight per cent of participants used eardrops before they dive, placing 2 3 drops into their ears half an hour before they dive. the protection of the hearing system is vital during sporting activities that potentially harm the auditory system, 25 therefore individuals should ensure that the ears are protected and hearing is monitored when diving. sub-aim (v): to determine whether the recreational scuba diver presents with audiological abnormalities related to diving, i.e. tinnitus, sensorineural hearing loss, vertigo and barotrauma table iv provides the results obtained from the participants, with regard to the symptoms experienced as a consequence of scuba diving. participants indicated that pain and barotrauma were the most common symptoms following the dives. all individuals who experienced a symptom due to diving continued to dive after the symptom subsided. participants indicated that symptoms were often recurrent. barotrama affects signifi cant structures within the auditory system such as the tympanic membrane, the eustachian tube, the middle-ear cavity and the inner ear. 5 vertigo and dizziness are common symptoms seen in divers, 26 and this has a drastic effect on the individual due to disorientation and focus. sub-aim (vi): to determine the actions of recreational divers who experience an audiological abnormality after diving eighty-three per cent of participants who experienced a complication following a dive consulted with a general practitioner (gp). they were all advised to resolve the problems before being able to continue with their diving. however, none was referred to an audiologist. none of the participants in this research study who experienced symptoms related to the auditory system received a hearing evaluation to ensure that no damage occurred within the audiological system. conclusion diving is a popular sport that is associated with audiological risks. the results from the current study indicate that scuba divers practise the correct method of equalisation during the dives to protect the auditory system. however, the need for audiological services prior the dive is not a priority. this research found that divers are not fully aware of the professional responsible for any hearing-related issues, therefore the implementation of a mandatory hearing screening for all potential divers would ensure that these individuals know who to go to if a hearing-related diffi culty arises after a dive. awareness of the risks of diving should be made clear to all potential divers to ensure that informed decisions are made. the role of the audiologist is vital in the monitoring and management of the risks associated with the sport. 27 medical procedures and policies related to scuba diving should be reviewed to ensure that potential divers are aware of the signifi cant risk of diving to the auditory system. medical practitioners should ensure that divers who experience trauma to the ear subsequent to diving should be referred for a diagnostic audiological assessment. audiologists should facilitate changes in the dive medical clearance assessment to include a diagnostic assessment so that the potential table iii. percentage of participants who were aware of the negative implications of diving negative implication percentage of participants burst eardrum 68% hearing loss 34% ear pain 34% barotrauma 25% deafness 17% infection 14% dizziness 8% secretion of fl uid 8% vertigo 5% damage to the middle ear 5% increased ear pressure 5% sinus pain 2% nausea 0 82 sajsm vol 22 no. 4 2010 diver is assessed and monitored regularly. this process would assist in minimising the ear-related risks involved with the sport. references 1. taylor dmd, o’toole ks, ryan cm. experienced scuba divers in australia and the united states suffer considerable injury and morbidity. wilderness and environmental medicine 2003;14(3):187-193. 2. shreeves k. the professional association of diving instructors: open water diver manual. international padi, inc: rancho santa margarita, 2008. 3. malinowski j, malinowski m. snorkel maui and lana’i: guide to the underwater world of hawaii. clifornia: indigo publications, 2000. 4. professional association of diving instructors. the undersea journal. los angeles: university of california, 2000. 5. neuman ts, thom sr. physiology and medicine of hyperbaric oxygen therapy. new york: elsevier health sciences, 2008. 6. nad. the noaa diving manual: diving for science and technology. usa: diane publishing, 1992. 7. graver dk. scuba diving. illinois: human kinetics, 2009. 8. strauss bm, aksenov ig. diving science. illinois: human kinetics, 2004. 9. du plessis c, fothergill d. gertner j, hughes l, schwaller d. a pilot study evaluating surfactant on eustachian tube function in divers. military medicine 2008; 173(12):1225-1232. 10. bantin j. the scuba diving handbook: the complete guide to safe and exciting scuba diving. los angeles: university of california, 2007. 11. bove aa. medical disorders related to diving. j int care med 2002;17(2):7586. 12. harrill wc. barotrauma of the middle and inner ear. the bobby r. alford department of otorhinolaryngology and communicative sciences, 1995. 13. aghababian r. essentials of emergency medicine. massachusetts: jones & bartlett, 2006. 14. pieterse i. the hearing abilities and middle ear functioning of the recreational scuba diver. department of communication pathology: university of pretoria, 2006. 15. lewins a, silver c. using software in qualitative research: a step-by-step guide. sage, 2007. 16. spector p. data manipulation with r. berkeley, california: springer, 2008. 17. burns n, grove sa. the practice of nursing research: conduct, critique and utilization. st louis, missouri: elsevier health sciences, 2005. 18. balnaves m, caputi p. introduction to quantitative research methods: an investigative approach. london: sage publications ltd, 2001. 19. oppenheim an. questionnaire design, interviewing and attitude measurement. london: pinter, 1992. 20. marshall c, rossman gb. designing qualitative research (4th ed). california: sage publications, inc. 2006. 21. bain c. malta & gozo: lonely planet malta (3rd ed). oakland, california: lonely planet publishers, 2007. 22. bove ad, davis jc. boves and davis diving medicine. philadelphia: elsevier health science, 2004. 23. young i, gherardin t. lonely planet healthy travel africa. lonely planet. south pacifi c underwater medicine society, 2009. 24. bulenkov sy. soviet manual of scuba diving. honolulu, hawaii: minerva group, 2004. 25. mckeag d, mckeag db, moeller jl . acsm’s primary care sports medicine. baltimore: lippincott williams & williams, 2007. 26. domino fj. the 5-minute clinical consult 2011. baltimore: lippincott williams & williams, 2010. 27. valente m, hosford-dunn h, roeser rj. audiology treatment. new york: thieme, 2008. sajsm vol 22 no. 4 2010 83 table iv. symptoms experienced by the scuba divers symptoms number of participants number of participants whose symptoms occurred more than once number of participants who continued diving once the symptom had disappeared very painful ear canals 8 4 8 painful eardrum 11 5 11 burst eardrum 3 2 3 excretion, other than water coming out your ears 0 0 0 dizziness 3 0 3 nausea 5 2 5 ringing, buzzing in the ear 6 2 6 sudden deafness, decreased hearing sensation 1 1 1 gradual decline in hearing sensation 1 0 1 barotrauma (ear pain due to increased pressure) 8 3 8 ear infections 6 1 6 cysts, growths 0 0 0 preamble this paper is a revision and update of the recommendations developed following the 1st (vienna) and 2nd (prague) international symposia on concussion in sport. (1, 2) the zurich consensus statement is designed to build on the principles outlined in the original vienna and prague documents and to develop further conceptual understanding of this problem using a formal consensus-based approach. a detailed description of the consensus process is outlined at the end of this document under the “background” section (see section 11). this document is developed for use by physicians, therapists, certified athletic trainers, health professionals, coaches and other people involved in the care of injured athletes, whether at the recreational, elite or professional level. while agreement exists pertaining to principal messages conveyed within this document, the authors acknowledge that the science of concussion is evolving and therefore management and return to play decisions remain in the realm of clinical judgment on an individualized basis. readers are encouraged to copy and distribute freely the zurich consensus document and/or the sports concussion assessment tool (scat2) card and neither is subject to any copyright restriction. the authors request, however that the document and/or the scat2 card be distributed in their full and complete format. the following focus questions formed the foundation for the zurich concussion consensus statement: acute simple concussion • which symptom scale & which sideline assessment tool is best for diagnosis and/or follow up? • how extensive should the cognitive assessment be in elite athletes? • how extensive should clinical and neuropsychological (np) testing be at non-elite level? • who should do/interpret the cognitive assessment? • is there a gender difference in concussion incidence and outcomes? return to play (rtp) issues • is provocative exercise testing useful in guiding rtp? • what is the best rtp strategy for elite athletes? • what is the best rtp strategy for non-elite athletes? • is protective equipment (e.g. mouthguards and helmets) useful in reducing concussion incidence and/or severity? complex concussion and long term issues • is the simple versus complex classification a valid and useful differentiation? consensus consensus statement on concussion in sport – the 3rd international conference on concussion in sport held in zurich, november 2008 author affiliations p mccrory – neurologist. director, centre for health, exercise & sports medicine, university of melbourne, parkville, australia 3010 willem meeuwisse – sports physician, sport medicine centre, faculty of kinesiology, and department of community health sciences, faculty of medicine, university of calgary, 2500 university drive n.w., calgary, alberta, canada, t2n 1n4 karen johnston – neurosurgeon and director, sport concussion clinic, toronto rehabilitation institute, 550 university avenue, toronto, on, m5g 2a2 canada jiri dvorak – neurologist. director, fifa medical assessment and research center (f-marc) and schulthess clinic, zurich, switzerland mark aubry – chief medical officer, international ice hockey federation and hockey canada, co-director ottawa sport medicine centre, 1370 clyde avenue, ottawa, canada, k1t 3y8 mick molloy – chief medical officer, international rugby board, huguenot house, 35-38 st stephen’s green, dublin 2, ireland robert cantu – neurosurgeon, 131 ornac, suite 820, john cuming building, emerson hospital, concord, ma 01742 usa correspondence a/prof paul mccrory centre for health, exercise & sports medicine university of melbourne, parkville, australia 3010 tel: +61 3 8344 4135 fax: +61 3 8344 3771 e-mail: paulmccr@bigpond.net.au competing interests: the authors have no competing interests to declare. this is a co-publication. see editorial on p.34 for details. p mccrory, w meeuwisse, k johnston, j dvorak, m aubry, m molloy, r cantu consensus panellists (listed in alphabetical order): in addition to the authors above, the consensus panellists were broglio s, davis g, dick r, dvorak j, echemendia r, gioia g, guskiewicz k, herring s, iverson g, kelly j, kissick j, makdissi m, mccrea m, ptito a, purcell l, putukian m. also invited but not in attendance: bahr r, engebretsen l, hamlyn p, jordan b, schamasch p 36 sajsm vol 21 no. 2 2009 • are there specific patient populations at risk of long-term problems? • is there a role for additional tests (e.g. structural and/or functional mr imaging, balance testing, biomarkers)? • should athletes with persistent symptoms be screened for depression/anxiety? paediatric concussion • which symptoms scale is appropriate for this age group? • which tests are useful and how often should baseline testing be performed in this age group? • what is the most appropriate rtp guideline for elite and non-elite child and adolescent athlete? future directions • what is the best method of knowledge transfer and education • is there evidence that new and novel injury prevention strategies work (e.g. changes to rules of the game, fair play strategies etc)? the zurich document additionally examines the management issues raised in the previous prague and vienna documents and applies the consensus questions to these areas. specific research questions and consensus discussion 1) concussion 1.1 definition of concussion panel discussion regarding the definition of concussion and its separation from mild traumatic brain injury (mtbi) was held. although there was acknowledgement that the terms refer to different injury constructs and should not be used interchangeably, it was not felt that the panel would define mtbi for the purpose of this document. there was unanimous agreement however that concussion is defined as follows: concussion is defined as a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces. several common features that incorporate clinical, pathologic and biomechanical injury constructs that may be utilized in defining the nature of a concussive head injury include: 1. concussion may be caused either by a direct blow to the head, face, neck or elsewhere on the body with an ‘‘impulsive’’ force transmitted to the head. 2. concussion typically results in the rapid onset of short lived impairment of neurologic function that resolves spontaneously. 3. concussion may result in neuropathological changes but the acute clinical symptoms largely reflect a functional disturbance rather than a structural injury. 4. concussion results in a graded set of clinical symptoms that may or may not involve loss of consciousness. resolution of the clinical and cognitive symptoms typically follows a sequential course however it is important to note that in a small percentage of cases however, post-concussive symptoms may be prolonged. 5. no abnormality on standard structural neuroimaging studies is seen in concussion. 1.2 classification of concussion there was unanimous agreement to abandon the simple vs. complex terminology that had been proposed in the prague agreement statement as the panel felt that the terminology itself did not fully describe the entities. the panel however unanimously retained the concept that the majority (80-90%) of concussions resolve in a short (7-10 day) period, although the recovery time frame may be longer in children and adolescents.(2) 2) concussion evaluation 2.1 symptoms and signs of acute concussion the panel agreed that the diagnosis of acute concussion usually involves the assessment of a range of domains including clinical symptoms, physical signs, behavior, balance, sleep and cognition. furthermore, a detailed concussion history is an important part of the evaluation both in the injured athlete and when conducting a preparticipation examination. the detailed clinical assessment of concussion is outlined in the scat2 form, which is an appendix to this document. the suspected diagnosis of concussion can include one or more of the following clinical domains: (a) symptoms – somatic (e.g. headache), cognitive (e.g. feeling like in a fog) and/or emotional symptoms (e.g. lability) (b) physical signs (e.g. loss of consciousness, amnesia) (c) behavioural changes (e.g. irritablity) (d) cognitive impairment (e.g. slowed reaction times) (e) sleep disturbance (e.g. drowsiness) if any one or more of these components is present, a concussion should be suspected and the appropriate management strategy instituted. 2.2 on-field or sideline evaluation of acute concussion when a player shows any features of a concussion: (a) the player should be medically evaluated onsite using standard emergency management principles and particular attention should be given to excluding a cervical spine injury. (b) the appropriate disposition of the player must be determined by the treating healthcare provider in a timely manner. if no healthcare provider is available, the player should be safely removed from practice or play and urgent referral to a physician arranged. (c) once the first aid issues are addressed, then an assessment of the concussive injury should be made using the scat2 or other similar tool. (d) the player should not be left alone following the injury and serial monitoring for deterioration is essential over the initial few hours following injury. (e) a player with diagnosed concussion should not be allowed to return to play on the day of injury. occasionally in adult athletes, there may be return to play on the same day as the injury. see section 4.2 it was unanimously agreed that sufficient time for assessment and adequate facilities should be provided for the appropriate medical assessment both on and off the field for all injured athletes. in some sports this may require rule change to allow an off-field medical assessment to occur without affecting the flow of the game or unduly penalizing the injured player’s team. sajsm vol 21 no. 2 2009 37 sideline evaluation of cognitive function is an essential component in the assessment of this injury. brief neuropsychological test batteries that assess attention and memory function have been shown to be practical and effective. such tests include the maddocks questions (3, 4) and the standardized assessment of concussion (sac). (5-7) it is worth noting that standard orientation questions (e.g. time, place, person) have been shown to be unreliable in the sporting situation when compared with memory assessment. (4, 8) it is recognized, however, that abbreviated testing paradigms are designed for rapid concussion screening on the sidelines and are not meant to replace comprehensive neuropsychological testing which is sensitive to detect subtle deficits that may exist beyond the acute episode; nor should they be used as a stand-alone tool for the ongoing management of sports concussions. it should also be recognized that the appearance of symptoms might be delayed several hours following a concussive episode. 2.3 evaluation in emergency room or office by medical personnel an athlete with concussion may be evaluated in the emergency room or doctor’s office as a point of first contact following injury or may have been referred from another care provider. in addition to the points outlined above, the key features of this exam should encompass: (a) a medical assessment including a comprehensive history and detailed neurological examination including a thorough assessment of mental status, cognitive functioning and gait and balance. (b) a determination of the clinical status of the patient including whether there has been improvement or deterioration since the time of injury. this may involve seeking additional information from parents, coaches, teammates and eyewitness to the injury. (c) a determination of the need for emergent neuroimaging in order to exclude a more severe brain injury involving a structural abnormality in large part, these points above are included in the scat2 assessment, which forms part of the zurich consensus statement. 3) concussion investigations a range of additional investigations may be utilized to assist in the diagnosis and/or exclusion of injury. these include: 3.1 neuroimaging it was recognized by the panelists that conventional structural neuroimaging is normal in concussive injury. given that caveat, the following suggestions are made: brain ct (or where available mr brain scan) contributes little to concussion evaluation but should be employed whenever suspicion of an intra-cerebral structural lesion exists. examples of such situations may include prolonged disturbance of conscious state, focal neurological deficit or worsening symptoms. newer structural mri modalities including gradient echo, perfusion and diffusion imaging have greater sensitivity for structural abnormalities. however, the lack of published studies as well as absent pre-injury neuroimaging data limits the usefulness of this approach in clinical management at the present time. in addition, the predictive value of various mr abnormalities that may be incidentally discovered is not established at the present time. other imaging modalities such as fmri demonstrate activation patterns that correlate with symptom severity and recovery in concussion. (9-13) whilst not part of routine assessment at the present time, they nevertheless provide additional insight to pathophysiological mechanisms. alternative imaging technologies (e.g. positron emission tomography, diffusion tensor imaging, magnetic resonance spectroscopy, functional connectivity), while demonstrating some compelling findings, are still at early stages of development and cannot be recommended other than in a research setting. 3.2 objective balance assessment published studies, using both sophisticated force plate technology, as well as those using less sophisticated clinical balance tests (e.g. balance error scoring system (bess)), have identified postural stability deficits lasting approximately 72 hours following sport-related concussion. it appears that postural stability testing provides a useful tool for objectively assessing the motor domain of neurologic functioning, and should be considered a reliable and valid addition to the assessment of athletes suffering from concussion, particularly where symptoms or signs indicate a balance component. (14-20) 3.3 neuropsychological assessment the application of neuropsychological (np) testing in concussion has been shown to be of clinical value and continues to contribute significant information in concussion evaluation. (21-26) although in most case cognitive recovery largely overlaps with the time course of symptom recovery, it has been demonstrated that cognitive recovery may occasionally precede or more commonly follow clinical symptom resolution suggesting that the assessment of cognitive function should be an important component in any return to play protocol. (27, 28) it must be emphasized however, that np assessment should not be the sole basis of management decisions rather it should be seen as an aid to the clinical decision-making process in conjunction with a range of clinical domains and investigational results. neuropsychologists are in the best position to interpret np tests by virtue of their background and training. however, there may be situations where neuropsychologists are not available and other medical professionals may perform or interpret np screening tests. the ultimate return to play decision should remain a medical one in which a multidisciplinary approach, when possible, has been taken. in the absence of np and other (e.g. formal balance assessment) testing, a more conservative return to play approach may be appropriate. in the majority of cases, np testing will be used to assist return to play decisions and will not be done until patient is symptom free. (29, 30) there may be situations (e.g. child and adolescent athletes) where testing may be performed early whilst the patient is still symptomatic to assist in determining management. this will normally be best determined in consultation with a trained neuropsychologist. (31, 32) 3.4 genetic testing the significance of apolipoprotein (apo) e4, apoe promotor gene, tau polymerase and other genetic markers in the management of sports concussion risk or injury outcome is unclear at this time. (33, 34) evidence from human and animal studies in more severe traumatic brain injury demonstrate induction of a variety of genetic and cytokine factors such as: insulin-like growth factor-1 (igf-1), igf binding protein-2, fibroblast growth factor, cu-zn superoxide dismutase, superoxide dismutase -1 (sod-1), nerve growth factor, glial fibrillary acidic protein (gfap) and s-100. whether such factors are affected in sporting concussion is not known at this stage. (35-42) 38 sajsm vol 21 no. 2 2009 3.5 experimental concussion assessment modalities different electrophysiological recording techniques (e.g. evoked response potential (erp), cortical magnetic stimulation and electroencephalography) have demonstrated reproducible abnormalities in the post concussive state, however not all studies reliably differentiated concussed athletes from controls. (43-49) the clinical significance of these changes remains to be established. in addition, biochemical serum and cerebral spinal fluid markers of brain injury (including s-100, neuron specific enolase (nse), myelin basic protein (mbp), gfap, tau etc) have been proposed as means by which cellular damage may be detected if present. (50-56) there is currently insufficient evidence however, to justify the routine use of these biomarkers clinically. 4) concussion management the cornerstone of concussion management is physical and cognitive rest until symptoms resolve and then a graded program of exertion prior to medical clearance and return to play. the recovery and outcome of this injury may be modified by a number of factors that may require more sophisticated management strategies. these are outlined in the section on modifiers below. as described above, the majority of injuries will recover spontaneously over several days. in these situations, it is expected that an athlete will proceed progressively through a stepwise return to play strategy. (57) during this period of recovery while symptomatic following an injury, it is important to emphasize to the athlete that physical and cognitive rest is required. activities that require concentration and attention (e.g. scholastic work, videogames, text messaging etc) may exacerbate symptoms and possibly delay recovery. in such cases, apart from limiting relevant physical and cognitive activities (and other risk-taking opportunities for re-injury) while symptomatic, no further intervention is required during the period of recovery and the athlete typically resumes sport without further problem. 4.1 graduated return to play protocol return to play protocol following a concussion follows a stepwise process as outlined in table 1. with this stepwise progression, the athlete should continue to proceed to the next level if asymptomatic at the current level. generally each step should take 24 hours so that an athlete would take approximately one week to proceed through the full rehabilitation protocol once they are asymptomatic at rest and with provocative exercise. if any post concussion symptoms occur while in the stepwise program then the patient should drop back to the previous asymptomatic level and try to progress again after a further 24-hour period of rest has passed. 4.2 same day rtp with adult athletes, in some settings, where there are team physicians experienced in concussion management and sufficient resources (e.g. access to neuropsychologists, consultants, neuroimaging etc) as well as access to immediate (i.e. sideline) neuro-cognitive assessment, return to play management is may be more rapid. the rtp strategy must still follow the same basic management principles namely, full clinical and cognitive recovery before consideration of return to play. this approach is supported by published guidelines, such as the american academy of neurology, us team physician consensus statement, and us national athletic trainers association position statement. (58-60) this issue was extensively discussed by the consensus panelists and it was acknowledged that there is evidence that some professional american football players are able to rtp more quickly, with even same day rtp supported by nfl studies without a risk of recurrence or sequelae. (61) there is data however, demonstrating that at the collegiate and high school level, athletes allowed to rtp on the same day may demonstrate np deficits post-injury that may not be evident on the sidelines and are more likely to have delayed onset of symptoms. (62-68) it should be emphasised however, the young (<18) elite athlete should be treated more conservatively even though the resources may be the same as an older professional athlete. (see section 6.1) 4.3 psychological management and mental health issues in addition, psychological approaches may have potential application in this injury, particularly with the modifiers listed below. (69, 70) care givers are also encouraged to evaluate the concussed athlete for affective symptoms such as depression as these symptoms may be common in concussed athletes.(57) 4.4 the role of pharmacological therapy pharmacological therapy in sports concussion may be applied in two distinct situations. the first of these situations is the management of specific prolonged symptoms (e.g. sleep disturbance, anxiety etc.). the second situation is where drug therapy is used to modify the underlying pathophysiology of the condition with the aim of shortening the duration of the concussion symptoms.(71) in broad terms, this approach to management should be only considered by clinicians experienced in concussion management. an important consideration in rtp is that concussed athletes should not only be symptom free but also should not be taking any pharmacological agents/medications that may mask or modify the symptoms of concussion. where antidepressant therapy may be commenced during the management of a concussion, the decision to return to play while still on such medication must be considered carefully by the treating clinician. 4.5 the role of pre-participation concussion evaluation recognizing the importance of a concussion history, and appreciating the fact that many athletes will not recognize all the concussions they may have suffered in the past, a detailed concussion history is table 1: graduated return to play protocol rehabilitation functional exercise at each objective stage stage of rehabilitation of each stage 1. no activity complete physical recovery and cognitive rest. 2.light aerobic walking, swimming or increase hr exercise stationary cycling keeping intensity < 70% mphr no resistance training. 3.sport-specific skating drills in ice hockey, add movement exercise running drills in soccer. no head impact activities. 4.non-contact progression to more exercise, training drills complex training drills e,g. coordination, passing drills in football and and cognitive ice hockey. may start load progressive resistance training) restore 5.full contact following medical clearance confidence and practice participate in normal training assess activities functional skills by coaching staff 6.return to play normal game play sajsm vol 21 no. 2 2009 39 of value. (72-75) such a history may pre-identify athletes that it into a high risk category and provides an opportunity for the healthcare provider to educate the athlete in regard to the significance of concussive injury. a structured concussion history should include specific questions as to previous symptoms of a concussion; not just the perceived number of past concussions. it is also worth noting that dependence upon the recall of concussive injuries by teammates or coaches has been demonstrated to be unreliable. (72) the clinical history should also include information about all previous head, face or cervical spine injuries as these may also have clinical relevance. it is worth emphasizing that in the setting of maxillofacial and cervical spine injuries, coexistent concussive injuries may be missed unless specifically assessed. questions pertaining to disproportionate impact versus symptom severity matching may alert the clinician to a progressively increasing vulnerability to injury. as part of the clinical history it is advised that details regarding protective equipment employed at time of injury be sought, both for recent and remote injuries. the benefit a comprehensive pre-participation concussion evaluation allows for modification and optimization of protective behavior and an opportunity for education. 5) modifying factors in concussion management the consensus panel agreed that a range of ‘modifying’ factors may influence the investigation and management of concussion and in some cases, may predict the potential for prolonged or persistent symptoms. these modifiers would also be important to consider in a detailed concussion history and are outlined in table 2. in this setting, there may be additional management considerations beyond simple rtp advice. there may be a more important role for additional investigations including: formal np testing, balance assessment, and neuroimaging. it is envisioned that athletes with such modifying features would be managed in a multidisciplinary manner coordinated by a physician with specific expertise in the management of concussive injury. the role of female gender as a possible modifier in the management of concussion was discussed at length by the panel. there was not unanimous agreement that the current published research evidence is conclusive that this should be included as a modifying factor although it was accepted that gender may be a risk factor for injury and/or influence injury severity. (76-78) 5.1 the significance of loss of consciousness (loc) in the overall management of moderate to severe traumatic brain injury, duration of loc is an acknowledged predictor of outcome. (79) whilst published findings in concussion describe loc associated with specific early cognitive deficits it has not been noted as a measure of injury severity. (80, 81) consensus discussion determined that prolonged (> 1 minute duration) loc would be considered as a factor that may modify management. 5.2 the significance of amnesia and other symptoms there is renewed interest in the role of post-traumatic amnesia and its role as a surrogate measure of injury severity.(67, 82, 83) published evidence suggests that the nature, burden and duration of the clinical post-concussive symptoms may be more important than the presence or duration of amnesia alone. (80, 84, 85) further it must be noted that retrograde amnesia varies with the time of measurement post-injury and hence is poorly reflective of injury severity.(86, 87) 5.3 motor and convulsive phenomena a variety of immediate motor phenomena (e.g. tonic posturing) or convulsive movements may accompany a concussion. although dramatic, these clinical features are generally benign and require no specific management beyond the standard treatment of the underlying concussive injury. (88, 89) 5.4 depression mental health issues (such as depression) have been reported as a long-term consequence of traumatic brain injury including sports related concussion. neuroimaging studies using fmri suggest that a depressed mood following concussion may reflect an underlying pathophysiological abnormality consistent with a limbic-frontal model of depression. (52, 90-100) 6) special populations 6.1 the child and adolescent athlete there was unanimous agreement by the panel that the evaluation and management recommendations contained herein could be applied to children and adolescents down to the age of 10 years. below that age children report different concussion symptoms different from adults and would require age appropriate symptom checklists as a component of assessment. an additional consideration in assessing the child or adolescent athlete with a concussion is that in the clinical evaluation by the healthcare professional there may be the need to include both patient and parent input as well as teacher and school input when appropriate. (101-107) the decision to use np testing is broadly the same as the adult assessment paradigm. however, timing of testing may differ in order to assist planning in school and home management (and may be performed while the patient is still symptomatic). if cognitive testing is performed then it must be developmentally sensitive until late teen years due to the ongoing cognitive maturation that occurs during this period which, in turn, makes the utility of comparison to either the person’s own baseline performance or to population norms limited. (20) in this age group it is more important to consider the use of trained neuropsychologists to interpret assessment data, particularly in children with learning disorders and/or adhd who may need more sophisticated assessment strategies. (31, 32, 101) table 2: concussion modifiers factors modifier symptoms number duration (> 10 days) severity signs prolonged loc (> 1min), amnesia sequelae concussive convulsions temporal frequency repeated concussions over time timing injuries close together in time “recency” recent concussion or tbi threshold repeated concussions occurring with progressively less impact force or slower recovery after each successive concussion. age child and adolescent (< 18 years old) co and premigraine, depression or other mental health morbidities disorders, attention deficit hyperactivity disorder (adhd), learning disabilities (ld), sleep disorders medication psychoactive drugs, anticoagulants behaviour dangerous style of play sport high risk activity, contact and collision sport, high sporting level 40 sajsm vol 21 no. 2 2009 the panel strongly endorsed the view that children should not be returned to practice or play until clinically completely symptom free, which may require a longer time frame than for adults. in addition, the concept of ‘cognitive rest’ was highlighted with special reference to a child’s need to limit exertion with activities of daily living and to limit scholastic and other cognitive stressors (e.g text messaging, videogames etc) while symptomatic. school attendance and activities may also need to be modified to avoid provocation of symptoms. because of the different physiological response & longer recovery after concussion and specific risks (e.g. diffuse cerebral swelling) related to head impact during childhood and adolescence, a more conservative return to play approach is recommended. it is appropriate to extend the amount of time of asymptomatic rest and/ or the length of the graded exertion in children and adolescents. it is not appropriate for a child or adolescent athlete with concussion to rtp on the same day as the injury regardless of the level of athletic performance. concussion modifiers apply even more to this population than adults and may mandate more cautious rtp advice. 6.2 elite vs non-elite athletes the panel unanimously agreed that all athletes regardless of level of participation should be managed using the same treatment and return to play paradigm. a more useful construct was agreed whereby the available resources and expertise in concussion evaluation were of more importance in determining management than a separation between elite and non-elite athlete management. although formal baseline np screening may be beyond the resources of many sports or individuals, it is recommended that in all organized high risk sports consideration be given to having this cognitive evaluation regardless of the age or level of performance. 6.3 chronic traumatic brain injury epidemiological studies have suggested an association between repeated sports concussions during a career and late life cognitive impairment. similarly, case reports have noted anecdotal cases where neuro-pathological evidence of chronic traumatic encephalopathy was observed in retired football players. (108-112) panel discussion was held and no consensus was reached on the significance of such observations at this stage. clinicians need to be mindful of the potential for long-term problems in the management of all athletes. 7) injury prevention 7.1 protective equipment – mouthguards and helmets there is no good clinical evidence that currently available protective equipment will prevent concussion although mouthguards have a definite role in preventing dental and oro-facial injury. biomechanical studies have shown a reduction in impact forces to the brain with the use of head gear and helmets, but these findings have not been translated to show a reduction in concussion incidence. for skiing and snowboarding there are a number of studies to suggest that helmets provide protection against head and facial injury and hence should be recommended for participants in alpine sports. (113-116) in specific sports such as cycling, motor and equestrian sports, protective helmets may prevent other forms of head injury (e.g. skull fracture) that are related to falling on hard road surfaces and these may be an important injury prevention issue for those sports. (116128) 7.2 rule change consideration of rule changes to reduce the head injury incidence or severity may be appropriate where a clear-cut mechanism is implicated in a particular sport. an example of this is in football (soccer) where research studies demonstrated that upper limb to head contact in heading contests accounted for approximately 50% of concussions. (129). as noted earlier, rule changes also may be needed in some sports to allow an effective off-field medical assessment to occur without compromising the athlete’s welfare, affecting the flow of the game or unduly penalizing the player’s team. it is important to note that rule enforcement may be a critical aspect of modifying injury risk in these settings and referees play an important role in this regard. 7.3 risk compensation an important consideration in the use of protective equipment is the concept of risk compensation. (130) this is where the use of protective equipment results in behavioral change such as the adoption of more dangerous playing techniques, which can result in a paradoxical increase in injury rates. this may be a particular concern in child and adolescent athletes where head injury rates are often higher than in adult athletes. (131-133) 7.4 aggression versus violence in sport the competitive/aggressive nature of sport which makes it fun to play and watch should not be discouraged. however, sporting organizations should be encouraged to address violence that may increase concussion risk. (134, 135) fair play and respect should be supported as key elements of sport. 8) knowledge transfer as the ability to treat or reduce the effects of concussive injury after the event is minimal, education of athletes, colleagues and the general public is a mainstay of progress in this field. athletes, referees, administrators, parents, coaches and health care providers must be educated regarding the detection of concussion, its clinical features, assessment techniques and principles of safe return to play. methods to improve education including web-based resources, educational videos and international outreach programs are important in delivering the message. in addition, concussion working groups plus the support and endorsement of enlightened sport groups such as fédération internationale de football association (fifa), international olympic commission (ioc), international rugby board (irb) and international ice hockey federation (iihf) who initiated this endeavor have enormous value and must be pursued vigorously. fair play and respect for opponents are ethical values that should be encouraged in all sports and sporting associations. similarly coaches, parents and managers play an important part in ensuring these values are implemented on the field of play. (57, 136-148) 9) future directions the consensus panelists recognize that research is needed across a range of areas in order to answer some critical research questions. the key areas for research identified include: • validation of the scat2 • gender effects on injury risk, severity and outcome • paediatric injury and management paradigms • virtual reality tools in the assessment of injury • rehabilitation strategies (e.g. exercise therapy) • novel imaging modalities and their role in clinical assessment • concussion surveillance using consistent definitions and outcome measures • clinical assessment where no baseline assessment has been performed sajsm vol 21 no. 2 2009 41 • ‘best-practice’ neuropsychological testing • long term outcomes • on-field injury severity predictors 10) medical legal considerations this consensus document reflects the current state of knowledge and will need to be modified according to the development of new knowledge. it provides an overview of issues that may be of importance to healthcare providers involved in the management of sports related concussion. it is not intended as a standard of care, and should not be interpreted as such. this document is only a guide, and is of a general nature, consistent with the reasonable practice of a healthcare professional. individual treatment will depend on the facts and circumstances specific to each individual case. it is intended that this document will be formally reviewed and updated prior to 1 december 2012. 11) statement on background to consensus process in november 2001, the 1st international conference on concussion in sport was held in vienna, austria. this meeting was organized by the iihf in partnership with fifa and the medical commission of the ioc. as part of the resulting mandate for the future, the need for leadership and future updates were identified. the 2nd international conference on concussion in sport was organized by the same group with the additional involvement of the irb and was held in prague, czech republic in november 2004. the original aims of the symposia were to provide recommendations for the improvement of safety and health of athletes who suffer concussive injuries in ice hockey, rugby, football (soccer) as well as other sports. to this end, a range of experts were invited to both meetings to address specific issues of epidemiology, basic and clinical science, injury grading systems, cognitive assessment, new research methods, protective equipment, management, prevention and long term outcome. (1, 2) the 3rd international conference on concussion in sport was held in zurich, switzerland on 29/30 october 2008 and was designed as a formal consensus meeting following the organizational guidelines set forth by the us national institutes of health. (details of the consensus methodology can be obtained at: http://consensus.nih. gov/aboutcdp.htm) the basic principles governing the conduct of a consensus development conference are summarized below: 1. a broad based non-government, non-advocacy panel was assembled to give balanced, objective and knowledgeable attention to the topic. panel members excluded anyone with scientific or commercial conflicts of interest and included researchers in clinical medicine, sports medicine, neuroscience, neuroimaging, athletic training and sports science. 2. these experts presented data in a public session, followed by inquiry and discussion. the panel then met in an executive session to prepare the consensus statement. 3. a number of specific questions were prepared and posed in advance to define the scope and guide the direction of the conference. the principle task of the panel was to elucidate responses to these questions. these questions are outlined below. 4. a systematic literature review was prepared and circulated in advance for use by the panel in addressing the conference questions. 5. the consensus statement is intended to serve as the scientific record of the conference. 6. the consensus statement will be widely disseminated to achieve maximum impact on both current health care practice and future medical research. the panel chairperson (wm) did not identify with any advocacy position. the chairperson was responsible for directing the consensus session and guiding the panel’s deliberations. panelists were drawn from clinical practice, academic and research in the field of sports related concussion. they do not represent organisations per se but were selected for their expertise, experience and understanding of this field. references 1. aubry m, cantu r, dvorak j, graf-baumann t, johnston k, kelly j, et al. summary and agreement statement of the first international conference on concussion in sport, vienna 2001. recommendations for the improvement of safety and health of athletes who may suffer concussive injuries. british journal of sports medicine. 2002 feb;36(1):6-10. 2. mccrory p, johnston k, meeuwisse w, aubry m, cantu r, dvorak j, et al. summary and agreement statement of the 2nd international conference on concussion in sport, prague 2004. british journal of sports medicine. 2005 apr;39(4):196-204. 3. maddocks d, dicker g. an objective measure of recovery from concussion in australian rules footballers. sport health. 1989;7(supplement):6-7. 4. maddocks dl, dicker gd, saling mm. the assessment of orientation following concussion in athletes. clin j sport med. 1995;5(1):32-5. 5. mccrea m. standardized mental status assessment of sports concussion. clin j sport med. 2001 jul;11(3):176-81. 6. mccrea m, kelly j, randolph c, kluge j, bartolic e, finn g, et al. standardised assessment of concussion (sac): on site mental status evaluation of the athlete. j head trauma rehab. 1998;13:27-36. 7. mccrea m, randolph c, kelly j. the standardized assessment of concussion (sac): manual for administration, scoring and interpretation. 2nd ed. waukesha, wi 2000. 8. mccrea m, kelly jp, kluge j, ackley b, randolph c. standardized assessment of concussion in football players. neurology. 1997 mar;48(3):5868. 9. chen j, johnston k, collie a, mccrory p, ptito a. a validation of the post concussion symptom scale in the assessment of complex concussion using cognitive testing and functional mri. j neurol neurosurg psych. 2007:in press. 10. chen j, johnston k, frey s, petrides m, worsley k, ptito a. functional abnormalities in symptomatic concussed athletes: an fmri study. neuroimage 2004;22(1):68-82. 11. chen jk, johnston km, collie a, mccrory p, ptito a. 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zazryn t. a pilot study of the attitudes of australian rules footballers towards protective headgear. j sci med sport. 2003 dec;6(4):505-11. 134. reece rm, sege r. childhood head injuries: accidental or inflicted? arch pediatr adolesc med. 2000 jan;154(1):11-5. 135. shaw nh. bodychecking in hockey. cmaj. 2004 jan 6;170(1):15-6; author reply 6, 8. 136. denke nj. brain injury in sports. j emerg nurs. 2008 aug;34(4):363-4. 137. gianotti s, hume pa. concussion sideline management intervention for rugby union leads to reduced concussion claims. neurorehabilitation. 2007;22(3):181-9. 138. guilmette tj, malia la, mcquiggan md. concussion understanding and management among new england high school football coaches. brain inj. 2007 sep;21(10):1039-47. 139. hootman jm, dick r, agel j. epidemiology of collegiate injuries for 15 sports: summary and recommendations for injury prevention initiatives. journal of athletic training. 2007 apr-jun;42(2):311-9. 140. valovich mcleod tc, schwartz c, bay rc. sport-related concussion misunderstandings among youth coaches. clin j sport med. 2007 mar;17(2):140-2. 141. sye g, sullivan sj, mccrory p. high school rugby players’ understanding of concussion and return to play guidelines. british journal of sports medicine. 2006 dec;40(12):1003-5. 142. theye f, mueller ka. “heads up”: concussions in high school sports. clin med res. 2004 aug;2(3):165-71. 143. kashluba s, paniak c, blake t, reynolds s, toller-lobe g, nagy j. a longitudinal, controlled study of patient complaints following treated mild traumatic brain injury. arch clin neuropsychol. 2004 sep;19(6):805-16. 144. gabbe b, finch cf, wajswelner h, bennell k. does community-level australian football support injury prevention research? j sci med sport. 2003 jun;6(2):231-6. 145. kaut kp, depompei r, kerr j, congeni j. reports of head injury and symptom knowledge among college athletes: implications for assessment and educational intervention. clin j sport med. 2003 jul;13(4):213-21. 146. davidhizar r, cramer c. “the best thing about the hospitalization was that the nurses kept me well informed” issues and strategies of client education. accid emerg nurs. 2002 jul;10(3):149-54. 147. mccrory p. what advice should we give to athletes postconcussion? british journal of sports medicine. 2002 oct;36(5):316-8. 148. bazarian jj, veenema t, brayer af, lee e. knowledge of concussion guidelines among practitioners caring for children. clin pediatr (phila). 2001 apr;40(4):207-12. appendix* *the appendix is available as a separate document on the website www.sajsm.org.za concussion should be suspected in the presence of any one or more of the following: symptoms (such as head­ ache), or physical signs (such as unsteadiness), or impaired brain function (e.g. confusion) or abnormal behaviour. 1. symptoms presence of any of the following signs & symptoms may suggest a concussion. pocket scat2 loss of consciousness� seizure or convulsion� amnesia� headache� “pressure in head” � neck pain� nausea or vomiting� dizziness� blurred vision� balance problems� sensitivity to light� sensitivity to noise� feeling slowed down� feeling like “in a fog“� “don’t feel right”� difficulty concentrating� difficulty remembering� fatigue or low energy� confusion� drowsiness� more emotional� irritability� sadness � nervous or anxious� 3. balance testing instructions for tandem stance “now stand heel-to-toe with your non-dominant foot in back. your weight should be evenly distributed across both feet. you should try to maintain stability for 20 seconds with your hands on your hips and your eyes closed. i will be counting the number of times you move out of this position. if you stumble out of this position, open your eyes and return to the start position and continue balancing. i will start timing when you are set and have closed your eyes.” observe the athlete for 20 seconds. if they make more than 5 errors (such as lift their hands off their hips; open their eyes; lift their forefoot or heel; step, stumble, or fall; or remain out of the start position for more that 5 seconds) then this may suggest a concussion. any athlete with a suspected concussion should be immediately removed from play, urgently assessed medically, should not be left alone and should not drive a motor vehicle. 2. memory function failure to answer all questions correctly may suggest a concussion. “at what venue are we at today?” “which half is it now?” “who scored last in this game?” “what team did you play last week / game?” “did your team win the last game?” sajsm vol 21 no. 2 2009 45 none mild moderate severe sport concussion assessment tool 2 symptom evaluation what is the scat2?1 this tool represents a standardized method of evaluating injured athletes for concussion and can be used in athletes aged from 10 years and older. it supersedes the original scat published in 20052. this tool also enables the calculation of the standardized assessment of concussion (sac)3, 4 score and the maddocks questions5 for sideline concussion assessment. instructions for using the scat2 the scat2 is designed for the use of medical and health professionals. preseason baseline testing with the scat2 can be helpful for interpreting post-injury test scores. words in italics throughout the scat2 are the instructions given to the athlete by the tester. this tool may be freely copied for distribtion to individuals, teams, groups and organizations. what is a concussion? a concussion is a disturbance in brain function caused by a direct or indirect force to the head. it results in a variety of nonspecific symptoms (like those listed below) and often does not involve loss of consciousness. concussion should be suspected in the presence of any one or more of the following: any athlete with a suspected concussion should be removed from play, medically assessed, monitored for deterioration (i.e., should not be left alone) and should not drive a motor vehicle. scat2 sport concussion assesment tool 2 | page 1 scat2 how do you feel? you should score yourself on the following symptoms, based on how you feel now. headache 0 1 2 3 4 5 6 “pressure in head” 0 1 2 3 4 5 6 neck pain 0 1 2 3 4 5 6 nausea or vomiting 0 1 2 3 4 5 6 dizziness 0 1 2 3 4 5 6 blurred vision 0 1 2 3 4 5 6 balance problems 0 1 2 3 4 5 6 sensitivity to light 0 1 2 3 4 5 6 sensitivity to noise 0 1 2 3 4 5 6 feeling slowed down 0 1 2 3 4 5 6 feeling like “in a fog“ 0 1 2 3 4 5 6 “don’t feel right” 0 1 2 3 4 5 6 difficulty concentrating 0 1 2 3 4 5 6 difficulty remembering 0 1 2 3 4 5 6 fatigue or low energy 0 1 2 3 4 5 6 confusion 0 1 2 3 4 5 6 drowsiness 0 1 2 3 4 5 6 trouble falling asleep (if applicable) 0 1 2 3 4 5 6 more emotional 0 1 2 3 4 5 6 irritability 0 1 2 3 4 5 6 sadness 0 1 2 3 4 5 6 nervous or anxious 0 1 2 3 4 5 6 total number of symptoms (maximum possible 22) symptom severity score (add all scores in table, maximum possible: 22 x 6 = 132) do the symptoms get worse with physical activity? y n do the symptoms get worse with mental activity? y n overall rating if you know the athlete well prior to the injury, how different is the athlete acting compared to his / her usual self? please circle one response. no different very different unsure name sport / team date / time of injury date / time of assessment age gender n m n f years of education completed examiner cognitive & physical evaluation symptom score (from page 1) 22 minus number of symptoms of 22 physical signs score was there loss of consciousness or unresponsiveness? y n if yes, how long? minutes was there a balance problem / unsteadiness? y n physical signs score (1 point for each negative response) of 2 glasgow coma scale (gcs) best eye response (e) no eye opening 1 eye opening in response to pain 2 eye opening to speech 3 eyes opening spontaneously 4 best verbal response (v) no verbal response 1 incomprehensible sounds 2 inappropriate words 3 confused 4 oriented 5 best motor response (m) no motor response 1 extension to pain 2 abnormal flexion to pain 3 flexion / withdrawal to pain 4 localizes to pain 5 obeys commands 6 glasgow coma score (e + v + m) of 15 gcs should be recorded for all athletes in case of subsequent deterioration. sideline assessment – maddocks score “i am going to ask you a few questions, please listen carefully and give your best effort.” modified maddocks questions (1 point for each correct answer) at what venue are we at today? 0 1 which half is it now? 0 1 who scored last in this match? 0 1 what team did you play last week / game? 0 1 did your team win the last game? 0 1 maddocks score of 5 maddocks score is validated for sideline diagnosis of concussion only and is not included in scat 2 summary score for serial testing. cognitive assessment standardized assessment of concussion (sac) orientation (1 point for each correct answer) what month is it? 0 1 what is the date today? 0 1 what is the day of the week? 0 1 what year is it? 0 1 what time is it right now? (within 1 hour) 0 1 orientation score of 5 immediate memory “i am going to test your memory. i will read you a list of words and when i am done, repeat back as many words as you can remember, in any order.” trials 2 & 3: “i am going to repeat the same list again. repeat back as many words as you can remember in any order, even if you said the word before.“ complete all 3 trials regardless of score on trial 1 & 2. read the words at a rate of one per second. score 1 pt. for each correct response. total score equals sum across all 3 trials. do not inform the athlete that delayed recall will be tested. list trial 1 trial 2 trial 3 alternative word list elbow 0 1 0 1 0 1 candle baby finger apple 0 1 0 1 0 1 paper monkey penny carpet 0 1 0 1 0 1 sugar perfume blanket saddle 0 1 0 1 0 1 sandwich sunset lemon bubble 0 1 0 1 0 1 wagon iron insect total immediate memory score of 15 concentration digits backward: “i am going to read you a string of numbers and when i am done, you repeat them back to me backwards, in reverse order of how i read them to you. for example, if i say 7-1-9, you would say 9-1-7.” if correct, go to next string length. if incorrect, read trial 2. one point possible for each string length. stop after incorrect on both trials. the digits should be read at the rate of one per second. alternative digit lists 4-9-3 0 1 6-2-9 5-2-6 4-1-5 3-8-1-4 0 1 3-2-7-9 1-7-9-5 4-9-6-8 6-2-9-7-1 0 1 1-5-2-8-6 3-8-5-2-7 6-1-8-4-3 7-1-8-4-6-2 0 1 5-3-9-1-4-8 8-3-1-9-6-4 7-2-4-8-5-6 months in reverse order: “now tell me the months of the year in reverse order. start with the last month and go backward. so you’ll say december, november ... go ahead” 1 pt. for entire sequence correct dec-nov-oct-sept-aug-jul-jun-may-apr-mar-feb-jan 0 1 concentration score of 5 scat2 sport concussion assesment tool 2 | page 2 1 4 5 2 3 3 mccrea m. standardized mental status testing of acute concussion. clinical journal of sports medicine. 2001; 11: 176-181 4 mccrea m, randolph c, kelly j. standardized assessment of concussion: manual for administration, scoring and interpretation. waukesha, wisconsin, usa. 5 maddocks, dl; dicker, gd; saling, mm. the assessment of orientation following concussion in athletes. clin j sport med. 1995;5(1):32–3 6 guskiewicz km. assessment of postural stability following sport-related concussion. current sports medicine reports. 2003; 2: 24-30 1 this tool has been developed by a group of international experts at the 3rd international consensus meeting on concussion in sport held in zurich, switzerland in november 2008. the full details of the conference outcomes and the authors of the tool are published in british journal of sports medicine, 2009, volume 43, supplement 1. the outcome paper will also be simultaneously co-published in the may 2009 issues of clinical journal of sports medicine, physical medicine & rehabilitation, journal of athletic training, journal of clinical neuroscience, journal of science & medicine in sport, neurosurgery, scandinavian journal of science & medicine in sport and the journal of clinical sports medicine. 2 mccrory p et al. summary and agreement statement of the 2nd international conference on concussion in sport, prague 2004. british journal of sports medicine. 2005; 39: 196-204 balance examination this balance testing is based on a modified version of the balance error scoring system (bess)6. a stopwatch or watch with a second hand is required for this testing. balance testing “i am now going to test your balance. please take your shoes off, roll up your pant legs above ankle (if applicable), and remove any ankle taping (if applicable). this test will consist of three twenty second tests with different stances.“ (a) double leg stance: “the first stance is standing with your feet together with your hands on your hips and with your eyes closed. you should try to maintain stability in that position for 20 seconds. i will be counting the number of times you move out of this position. i will start timing when you are set and have closed your eyes.“ (b) single leg stance: “if you were to kick a ball, which foot would you use? [this will be the dominant foot] now stand on your non-dominant foot. the dominant leg should be held in approximately 30 degrees of hip flexion and 45 degrees of knee flexion. again, you should try to maintain stability for 20 seconds with your hands on your hips and your eyes closed. i will be counting the number of times you move out of this position. if you stumble out of this position, open your eyes and return to the start position and continue balancing. i will start timing when you are set and have closed your eyes.“ (c) tandem stance: “now stand heel-to-toe with your non-dominant foot in back. your weight should be evenly distributed across both feet. again, you should try to maintain stability for 20 seconds with your hands on your hips and your eyes closed. i will be counting the number of times you move out of this position. if you stumble out of this position, open your eyes and return to the start position and continue balancing. i will start timing when you are set and have closed your eyes.” balance testing – types of errors 1. hands lifted off iliac crest 2. opening eyes 3. step, stumble, or fall 4. moving hip into > 30 degrees abduction 5. lifting forefoot or heel 6. remaining out of test position > 5 sec each of the 20-second trials is scored by counting the errors, or deviations from the proper stance, accumulated by the athlete. the examiner will begin counting errors only after the individual has assumed the proper start position. the modified bess is calculated by adding one error point for each error during the three 20-second tests. the maximum total number of errors for any single condition is 10. if a athlete commits multiple errors simultaneously, only one error is recorded but the athlete should quickly return to the testing position, and counting should resume once subject is set. subjects that are unable to maintain the testing procedure for a minimum of five seconds at the start are assigned the highest possible score, ten, for that testing condition. which foot was tested: left right (i.e. which is the non-dominant foot) condition total errors double leg stance (feet together) of 10 single leg stance (non-dominant foot) of 10 tandem stance (non-dominant foot at back) of 10 balance examination score (30 minus total errors) of 30 coordination examination upper limb coordination finger-to-nose (ftn) task: “i am going to test your coordination now. please sit comfortably on the chair with your eyes open and your arm (either right or left) outstretched (shoulder flexed to 90 degrees and elbow and fingers extended). when i give a start signal, i would like you to perform five successive finger to nose repetitions using your index finger to touch the tip of the nose as quickly and as accurately as possible.” which arm was tested: left right scoring: 5 correct repetitions in < 4 seconds = 1 note for testers: athletes fail the test if they do not touch their nose, do not fully extend their elbow or do not perform five repetitions. failure should be scored as 0. coordination score of 1 cognitive assessment standardized assessment of concussion (sac) delayed recall “do you remember that list of words i read a few times earlier? tell me as many words from the list as you can remember in any order.“ circle each word correctly recalled. total score equals number of words recalled. list alternative word list elbow candle baby finger apple paper monkey penny carpet sugar perfume blanket saddle sandwich sunset lemon bubble wagon iron insect delayed recall score of 5 overall score test domain score symptom score of 22 physical signs score of 2 glasgow coma score (e + v + m) of 15 balance examination score of 30 coordination score of 1 subtotal of 70 orientation score of 5 immediate memory score of 5 concentration score of 15 delayed recall score of 5 sac subtotal of 30 scat2 total of 100 maddocks score of 5 definitive normative data for a scat2 “cut-off” score is not available at this time and will be developed in prospective studies. embedded within the scat2 is the sac score that can be utilized separately in concussion management. the scoring system also takes on particular clinical significance during serial assessment where it can be used to document either a decline or an improvement in neurological functioning. scoring data from the scat2 or sac should not be used as a stand alone method to diagnose concussion, measure recovery or make decisions about an athlete’s readiness to return to competition after concussion. scat2 sport concussion assesment tool 2 | page 3 6 7 8 this patient has received an injury to the head. a careful medical examination has been carried out and no sign of any serious complications has been found. it is expected that recovery will be rapid, but the patient will need monitoring for a further period by a responsible adult. your treating physician will provide guidance as to this timeframe. if you notice any change in behaviour, vomiting, dizziness, worsening headache, double vision or excessive drowsiness, please telephone the clinic or the nearest hospital emergency department immediately. other important points: not use aspirin or anti-inflammatory medication not drive until medically cleared not train or play sport until medically cleared patient’s name date / time of injury date / time of medical review treating physician concussion injury advice (to be given to concussed athlete) signs to watch for problems could arise over the first 24-48 hours. you should not be left alone and must go to a hospital at once if you: remember, it is better to be safe. consult your doctor after a suspected concussion. return to play athletes should not be returned to play the same day of injury. when returning athletes to play, they should follow a stepwise symptom-limited program, with stages of progression. for example: 1. rest until asymptomatic (physical and mental rest) 2. light aerobic exercise (e.g. stationary cycle) 3. sport-specific exercise 4. non-contact training drills (start light resistance training) 5. full contact training after medical clearance 6. return to competition (game play) there should be approximately 24 hours (or longer) for each stage and the athlete should return to stage 1 if symptoms recur. resistance training should only be added in the later stages. medical clearance should be given before return to play. athlete information any athlete suspected of having a concussion should be removed from play, and then seek medical evaluation. scat2 sport concussion assesment tool 2 | page 4 contact details or stamp clinic phone number additional comments tool test domain time score date tested days post injury symptom score physical signs score glasgow coma score (e + v + m) scat2 balance examination score coordination score orientation score immediate memory score sac concentration score delayed recall score sac score total scat2 symptom severity score (max possible 132) return to play n y n n n y n n n y n n n y n n 46 sajsm vol 21 no. 2 2009 22 sajsm vol 24 no. 1 2012 editor’s choice the history and meaning of fatigue it is immensely difficult to provide a detailed historical account of the development of fatigue as a concept in the exercise sciences. however, the study of fatigue stretches back centuries to scientists such as galvani, who provided the ideas and tools to undertake experiments related to the electrical impulses needed to animate skeletal muscles.1 the definitive work of mosso in the 18th century stands as a landmark in the study of fatigue.2 in his book la fatica (fatigue),2 he concluded that there were two phenomena which categorised fatigue: “the first is the diminution of the muscular force. the second is fatigue as a sensation. that is to say, we have a physical fact which can be measured and compared, and a psychic fact which eludes measurement” (p 154). notably, early textbooks such as physiology of muscular exercise by bainbridge in 19313 pointed out that the limit of exercise “has often been ascribed to the capacity of the heart alone, but the facts as a whole indicate that the sum of the changes taking place throughout the body brings about the final cessation of effort” (p 176). it is an interesting fact that research into fatigue is highly complex, and consensus about the aetiology of this human condition still evades us. not surprisingly, even after centuries of research in this area, fatigue is still very much a part of medical and social discourse. there may be several reasons for this, not least of which could be the loss or change in the meaning of the term fatigue. the oxford dictionary4 defines fatigue as “extreme tiredness after exertion; reduction in efficiency of a muscle, organ etc. after prolonged activity”. compare this definition to that of exhaustion which is often used interchangeably by exercise physiologists and which is defined as “a total loss of strength; to consume or use up the whole of ”.4 clearly, these are substantially different meanings. in addition to these general meanings, there is wide variation in definitions of fatigue in the exercise sciences which include statements such as “the failure to maintain the required or expected force,”5 or “a loss of maximal force generating capacity”6 or “a reversible state of force depression, including a lower rate of rise of force and a slower relaxation”.7 there are many more statements or definitions like these which attempt to capture the specific observation that there has been a decline in the ability to produce skeletal muscle tension of a given magnitude in order to quantify the amount of fatigue that has developed. recently, it has been argued that meaning itself, the subjective sense a person attributes to an event or experience, tends to be overlooked in scientific research. as a result, we are left with a naïve understanding about the underlying mechanisms so that the subjective experience is nothing more than a series of brain states.8 the study of fatigue is an example of how scientific rules which ordinarily have finite meanings have constrained the pursuit of understanding the fatigue experience. central or peripheral fatigue? much of what is reported in the literature about the mechanisms of fatigue is related to the reductionist and sometimes mutually exclusive dichotomy of either peripheral or central mechanisms with conclusions usually drawn about the contribution of each to the total outcome. one might argue that such a dichotomous paradigm is appropriate since it provides insights about the processes at specific sites. from these site-specific changes, one can apparently conclude whether the site of fatigue is located in the central nervous system or peripherally at or below the neuromuscular junction. however, over a century ago, mosso wrote that “it is not will, not the nerves, but it is the muscle that finds itself worn out after the intense work of the brain”.2 mosso expressly noted that the “fatigue of brain reduces the strength of the muscles”. this is perhaps one of the initial statements in this area of work which gave rise to the central versus peripheral paradigm and it may be this “either/or” approach that limits our investigations and understanding of fatigue. moreover, this dichotomy excludes the obvious individual subjective assessment of fatigue. for example, during high intensity exercise of short duration, the fatigue that develops is thought to be primarily peripheral in origin so that the ability of the muscle to generate further tension is reduced because of changes to the properties of the surface membrane •this article was reproduced with permission from the bmj group. it was originally published in the british journal of sports medicine 2011;45:65-67 (originally published online 2 december 2009). the limits to exercise performance and the future of fatigue research* f e marino, m gard, e j drinkwater school of human movement studies, charles sturt university, bathurst, new south wales, australia correspondence to: professor frank e marino (fmarino@csu.edu.au) abstract the study of human fatigue stretches back centuries and remains a significant part of medical and social discourse. in the exercise sciences fatigue is routinely related to the ability to produce muscle force or to the recovery from force decrements. however, the study of fatigue has by virtue of the experimental paradigm excluded the subjective sense a person attributes to an event or experience, thus reducing our overall understanding of the fatigue process. modern studies report the causes of fatigue as either central or peripheral in origin. although useful, this dichotomy can also exclude the individual subjective assessment. furthermore, adhering dogmatically to set parameters is likely limiting the advancement of our understanding. a more realistic paradigm would permit the individual to use the sensory cues to adjust the effort along with the fatigue process rather than rely purely on feedback mechanisms. therefore, bringing feedforward mechanisms of the brain into fatigue research perhaps represents the next phase in the unravelling of the fatigue process. sajsm vol 24 no. 1 2012 23 of the muscle fibre, the process of calcium release or the function of excitation–contraction coupling9 (pp 105-119). however, if the familiar feelings or sensations of “burning” that develop during this process have no meaning for the individual and play no role, then this removes completely the possibility that the individual is not adjusting their effort either consciously or subconsciously during the exercise. it seems intuitive that individuals would have some say over the way in which they deal with the fatigue that develops during this short intense exercise bout. however, the evidence for this is lacking probably because the protocols used to study fatigue do not allow for the individual to adjust their response relative to the feedback which might be available during exercise. it is because most of these tests are externally driven by an experimenter dictating the pace by, for example, a motorised treadmill that these tests are referred to as “brainless”.10 definitions and models of fatigue there is an attraction to reaching a succinct and widely accepted definition of fatigue. such a definition would be convenient for scientific investigation by providing a metric upon which to compare results. to base much of the sports and exercise science research on firmer footing could also add credibility to the discipline among the other natural sciences that have much more standardised metrics and terms of reference. however, to prematurely arrive at a definition that is only accepted because no better one exists may only confirm our own biases and misrepresent the reality of fatigue. for example, concise and intuitive theory has led us to routinely, but erroneously, explain fatigue with “lactic acid” for many decades.11 as a consequence, decades of research estimating metabolic acidosis and buffering on “lactic acid” is based on flawed theory. considering our innate desire to understand a phenomenon, explaining fatigue with “lactic acidosis” persists12 even though there is now a gaping hole in our understanding of metabolic acidosis. similarly, that fatigue is based on feedback mechanisms has existed since hill’s so-called “catastrophe model” of fatigue.13 the interpretations of vo2max testing made by hill have guided how we quantify, understand and explain fatigue. that a model is concise or intuitive does not mean that we should cease looking to develop a better one, particularly when weaknesses in the catastrophe model come to light.14 while the “central governor theory”15 might not be the final explanation of fatigue,16 a feedforward mechanism presents what is potentially the next step in advancing our understanding of fatigue. considering that hill’s classical theory has undergone very little modification since its inception in the 1920s, is it possible that the constraints of this theory are contributing to limiting our understanding of fatigue? a feedforward mechanism for explaining fatigue attempts to encompass events in which fatigue exists without exhaustion. the term “exhaustion” here does not necessary imply complete physical collapse but simply the inability to maintain the prescribed task (ie, task failure).17 our current understanding of fatigue based on hill’s model cannot help us understand fatigue that involves voluntarily paced events like cycling time trials18 or team sports19 nor the fatigue associated with disease states.20 while most sporting events terminate with the occurrence of an event that is externally controlled (eg, the end of the race, expiry of the game clock), laboratory research investigating fatigue usually begins with no known end target and ends with voluntary termination. athletes must consciously self-pace themselves to time the end of the event with fatigue while maintaining optimal performance.21 22 by removing conscious control over pacing, tests like the vo2max are not specific to the phenomenon of self-paced events.13 applying research results from externally paced tests to help us understand fatigue during self-paced events is entirely inappropriate. it is possible that a multitude of explanations for fatigue exist, ranging from metabolic disturbances in the motor unit to mechanisms that are centrally mediated.23 the balance of central and peripheral mechanisms may be partially dependent upon duration/intensity of fatigue and the muscle group being assessed.24 however, that they are all based on feedback mechanisms seems to be a limiting factor in how we explain fatigue, particularly when considering the feedforward mechanisms necessary for the anticipation of fatigue and pacing strategies for self-paced events. while the nature of modern research often requires progressively greater specialization and refinement of theories, opportunities must be taken to discuss fatigue from a holistic perspective so that we can integrate different components of fatigue into a modern understanding. at least two future directions the future of research into fatigue during exercise points towards two potential lines of inquiry. first, there is the question of what we mean by the term fatigue. it is now clear that it can mean different things to different people. most obvious here is the point that an organism might be said to be “fatigued” according to a wide range of criteria. however, perhaps, a more fundamental point is that fatigue can refer to both states and processes and that these need to be considered both separately and synergistically. clearly, there will be times when an atomistic or reductive approach to understanding fatigue states and processes will be advantageous and other times when new knowledge will depend on abandoning the comfort of disciplinary, methodological or philosophical specialisation. a second potential future for fatigue research concerns the kinds of questions we are prepared and able to ask. for example, researchers interested in what we might broadly call the limits to performance are familiar with two widely accepted but incompatible propositions. first, there is evidence that without “artificial” aids such as drugs or genetic manipulation we are unlikely to see significant future improvement in world records for sports such as swimming and track and field.25 on the other hand, there are those who point to feats of super-endurance, such as those by the first arctic explorers or the early trans-continental race walkers, as evidence that we cannot really know how far or fast we might go because we are rarely faced with circumstances that threaten our very survival.26 taken together, these two propositions beg the question: are the limits to performance mechanical and immutable or fuzzy and suggestible? one way of managing the tension that is created by these points of view is simply to avoid it. for example, we might argue that if modern athletes were motivated by the fear of starvation and/or death, they would run faster. of course, this is sheer speculation at best. hypothetically, there is also the problem that this kind of “encouragement” might have the opposite effect. alternatively, we might argue that events such as the marathon and, say, walking 1000 km are both quantitatively and qualitatively different. in other words, it is not simply that the 1000-km race is longer than the marathon; to put it crudely, it could be that the limits to performance in a 1000-km race are predominantly mental, while the limits to performance in the marathon are predominantly physiological. this explanation has appeal, but there is always the lurking problem of differentiating the “mental” from the “physiological”. 24 sajsm vol 24 no. 1 2012 a third solution might be to say that it depends on the “maturity” of the event. ergo, in a highly competitive event such as the marathon, where lots of people are doing it and the prizes for winning are high, we reach the “limits” to performance fairly quickly (say, 100 years or so). however, super-endurance races are less popular, and, for this reason, we are proportionately much further away from the “limits” of performance in them. it is little wonder, then, that the limits to performance in this context appear to be “mental”. for example, consider the rate of collapse of ultramarathon runners after the finish of the race or nearer the times to win medals.27 none of these resolutions to the limits of p erformance dilemma seem adequate. perhaps, the problem here is that we now find ourselves pushing at a different set of limits the limits of the concepts we use and, in turn, the limits they place on the questions we are capable of asking. perhaps, some of the dilemmas we currently face concerning the nature of fatigue are an artefact of our reliance on concepts like “physiological”, “mental” and “psychological”. are these terms adequate anymore? what is clear is that we can no longer pretend that conscious and unconscious decision making plays no role in fatigue states and processes. this means that studying fatigue as a closed feedback loop will no longer suffice. at this stage in our understanding of the brain, bringing feedforward mechanisms of the brain into fatigue research has the obvious potential to make our work much more “fuzzy” and much less “mechanical”. for some, a fuzzy future will look too different from the past and make them turn away. for others, the possibility of inventing a new conceptual landscape with which to investigate/ unravel fatigue beckons. patient consent not needed. contributors each section of the manuscript was written by each of the authors. provenance and peer review not commissioned; externally peer reviewed. references 1. dougan a. raising the dead: the men who created frankenstein. edinburgh: birlinn limited, 2008. 2. mosso a. fatigue. london: swan sonnenschein & co ltd, 1904. 3. bainbridge fa. the physiology of muscular exercise. 3rd edn. new york, usa: longmans, green and co, 1931. 4. moore b, editor. the australian concise oxford dictionary. 4th edn. south melbourne: oxford university press, 2004. 5. edwards rht. human muscle function and fatigue. in: porter r, whelan j, eds. human muscle fatigue: physiological mechanisms. london: pitman medical, 1981:1–18. 6. bigland-ritchie b, furbush f, woods jj. fatigue of intermittent submaximal voluntary contractions: central and peripheral factors. j appl physiol 1986;61:421–9. 7. fitts rh, holloszy jo. effects of fatigue and recovery on contractile properties of frog muscle. j appl physiol 1978;45:899–902. 8. kretchmar rs. what to do with meaning? a research conundrum for the 21st century. quest 2007;59:373–83. 9. jones d, round j, de haan a. skeletal muscle: from molecules to movement. london: churchill-livingston, 2004. 10. noakes td. testing for maximum oxygen consumption has produced a brainless model of human exercise performance. br j sports med 2008;42:551–5. 11. robergs ra, ghiasvand f, parker d. biochemistry of exercise-induced metabolic acidosis. am j physiol regul integr comp physiol 2004;287:r502–16. 12. nakamura fy, soares-caldeira lf, laursen pb, et al. cardiac autonomic responses to repeated shuttle sprints. int j sports med 2009;30:808–13. 13. crewe h, tucker r, noakes td. the rate of increase in rating of perceived exertion predicts the duration of exercise to fatigue at a fixed power output in different environmental conditions. eur j appl physiol 2008;103:569–77. 14. ansley l, robson pj, st clair gibson a, et al. anticipatory pacing strategies during supramaximal exercise lasting longer than 30 s. med sci sports exerc 2004;36:309–14. 15. bam j, noakes td, juritz j, et al. could women outrun men in ultramarathon races? med sci sports exerc 1997;29:244–7. 16. weir jp, beck tw, cramer jt, et al. is fatigue all in your head? a critical review of the central governor model. br j sports med 2006;40:573–86; discussion 586. 17. hunter sk, duchateau j, enoka rm. muscle fatigue and the mechanisms of task failure. exerc sport sci rev 2004;32:44–9. 18. marino fe. heat reactions in multiple sclerosis: an overlooked paradigm in the study of comparative fatigue. int j hyperthermia 2009;25:34–40. 19. duffield r, coutts aj, quinn j. core temperature responses and match running performance during intermittent-sprint exercise competition in warm conditions. j strength cond res 2009;23:1238–44. 20. mock v, atkinson a, barsevick a, et al.; national comprehensive cancer network. nccn practice guidelines for cancer-related fatigue. oncology 2000;14:151–61. 21. gabbett tj. influence of fatigue on tackling technique in rugby league players. j strength cond res 2008;22:625–32. 22. royal ka, farrow d, mujika i, et al. the effects of fatigue on decision making and shooting skill performance in water polo players. j sports sci 2006;24:807–15. 23. enoka rm, duchateau j. muscle fatigue: what, why and how it influences muscle function. j physiol (lond) 2008;586:11–23. 24. behm dg, st-pierre dm. effects of fatigue duration and muscle type on voluntary and evoked contractile properties. j appl physiol 1997;82:1654–61. 25. nevill am, whyte g. are there limits to running world records? med sci sports exerc 2005;37:1785–8. 26. noakes td. the limits of endurance exercise. basic res cardiol 2006;101:408–17. 27. holtzhausen lm, noakes td, kroning b, et al. clinical and biochemical characteristics of collapsed ultra-marathon runners. med sci sports exerc 1994;26:1095–101. original research introduction long-term injury surveillance has been carried out in australia, south africa and england with the view to identifying injury patterns. 1-3 data of injuries to australian state and national cricketers were collected retrospectively for the first three seasons (1995 1996 season – 1997 1998 season) and then prospectively for the next six seasons (1999 2000 season – 2004 2005 season). 3 of the 886 injuries recorded, 92% were new injuries, 8% were recurrent injuries and 52% occurred during major matches. the injuries were mainly sustained while bowling (45%), with lower limb injuries accounting for 49% of the injuries. the mean incidence of injuries during matches for the season (injuries/10 000 player hours) was reported for domestic one-day (38.5), first-class (27.3), one-day international (odi) (59.8) and test (31.4) matches. fast bowlers missed about 16% of potential playing time because of injury, while other players missed less than 5%. the study in south africa 2 prospectively recorded 1 606 injuries in 783 national and provincial cricketers over a six-season period from 1998/1999 to 2003/2004. more injuries occurred during firstclass matches (32%), with limited-over matches (26%) and practices and training (27%) resulting in a similar number of injuries. fifteen per cent of the injuries accumulated gradually during the season. the majority of injuries were classified as acute injuries (65%), with chronic (23%) and acute-on-chronic (12%) injuries making up the balance. first-time injuries accounted for 65%, with the balance of injuries from the previous season (22%) and recurring again during the same season (13%). bowling (40%) accounted for the majority of the injuries, with 55% of these being lower limb injuries and 33% back and trunk injuries. of the 39 stress fractures, 79% occurred in bowlers. the primary activity associated with injury was the delivery and follow-through of the fast bowler (25%), running, diving, catching and throwing the ball when fielding (23%) and overuse (17%). other activities included various batting situations, such as being struck while batting (7%), running between the wickets (4%), batting for long periods at a time (4%), training specifically for cricket (4%) and participating in various other sports (3%). a retrospective study by leary and white 1 on 54 cricketers who had played for the same county first team in england between 1985 and 1995 reported 990 injuries, indicating an injury exposure of 17 247 days played and an injury incidence rate of 57.4 injuries per 1 000 days played. 1 most injuries were sustained early in the season, with bowlers most susceptible to injury (70.1 injuries per 1 000 days), followed by the all-rounders, batsmen and wicketkeepers with 55.0, 49.4 and 47.3 injuries per 1 000 days, respectively. most injuries occurred to the lower limbs (45%), with muscle/tendon strains, contusions/haematomas, and ligament/joint sprains the most common injuries. the most vulnerable sites for injury were the thigh and calf (25%), fingers (14%) and lumbar spine (11%). injury patterns of south african international cricket players over a two-season period correspondence: dr richard stretch nelson mandela metropolitan university po box 77000 port elizabeth 6031 e-mail: richard.stretch@nmmu.ac.za richard a stretch1 (dphil) ryan p raffan2 (ba, hms hons) 1 sport bureau, nelson mandela metropolitan university, port elizabeth, south africa 2 department of human movement science and sport management, nelson mandela metropolitan university, port elizabeth, south africa abstract objective. the aim of the study was to determine the incidence and nature of injury patterns of south african international cricket players. methods. a questionnaire was completed for each cricketer who presented with an injury during the 2004 2005 (s1) and 2005 2006 (s2) cricket seasons to determine the anatomical site, month, diagnosis and mechanism of injury. results. the results showed that 113 injuries were sustained, with a match exposure time of 1 906 hours for one-day internationals (odis) and 5 070 hours for test matches. the injury prevalence was 4% per match, while the incidence of injury was 90 injuries per 10 000 hours of matches. injuries occurred mostly to the lower limbs, back and trunk, upper limbs and head and neck. the injuries occurred primarily during test matches (43%), practices (20%) and practices and matches (19%). acute injuries comprised 87% of the injuries. the major injuries during s1 were haematomas (20 %), muscle strains (14%) and other trauma (20%), while during s2 the injuries were primarily muscle strains (16%), other trauma (32%), tendinopathy (10%) and acute sprains (12%). the primary mechanisms of injury occurred when bowling (67%), on impact by the ball (batting – 65%, fielding – 26%) and when sliding for the ball (19%). conclusion. the study provided prospective injury incidence and prevalence data for south african cricketers playing at international level over a two-season period, high-lighting the increased injury prevalence for away matches and an increased match injury incidence for test and odi matches possibly as a result of increased match exposure time. sajsm vol 23 no. 2 2011 45 46 sajsm vol 23 no. 2 2011 the first study to use the internationally recognised surveillance method 4 reported that 162 domestic and 33 international west indian cricketers sustained 50 injuries. most injuries were sustained in test and first-class matches (40%), with a further 28% sustained during one-day matches. the injury incidence for test and odi matches was 48.7 and 40.6 injuries per 10 000 player-hours, respectively. for domestic first-class and limited overs matches it was 13.9 and 25.4 injuries per 10 000 player-hours, respectively. the injury prevalence for test (11.3%) and odi (8.1%) matches was lower for home matches than away matches. bowlers (46%) and batsmen (40%) were at the greatest risk of injury, with muscles (26%) and ligament (12%) injuries, stress fractures (12%) and fractures (10%) the most common injuries. most of the injuries were new (80%), with 10% recurrent injuries from the previous season and 10% recurring again during the same season. all these injury surveillance studies, with the exception of the study on west indian cricketers, 4 were carried out prior to the international acceptance of the publication of the consensus paper regarding injury definitions, methods of calculating injury rates and reporting of injuries. 2 therefore, the aim of this study was to use the internationally agreed methods for injury surveillance to investigate the seasonal incidence and nature of injuries sustained by south african cricketers to further understand and identify injury patterns, risk factors and other possible factors associated with these injuries. methods during the 2004 2005 (s1) and 2005 2006 (s2) cricket seasons, test and odi matches played by the south african team were monitored prospectively. the data collection and reporting have been done according to the guidelines from the consensus paper developed to allow meaningful comparisons to be made with other international studies. 5 the physiotherapists working with the teams were required to complete a questionnaire for all cricketers who presented with an injury. the questionnaire was designed to obtain the following information: (i) biographical data; (ii) month of injury during the season; (iii) activity and time of onset of injury; (iv) whether it was a first-time injury or recurrent injury from the previous or current season; (v) chronicity of the injury; (vi) whether the injury had recurred again during the season; (vii) osics 6 injury classification code; (viii) diagnosis; and (ix) mechanism of injury. further, in order to determine the player exposure it was necessary to collect information of the player’s participation in each match, reasons for non-participation in a match and duration of the match. 2 for the purpose of this research, an injury was defined as any injury or other medical condition that either: (i) prevents a player from being fully available for selection for a major match; or (ii) during a major match, causes a player to be unable to bat, bowl or keep wicket when required by either the rules or the team’s captain. 5 acute injuries were those of rapid onset, chronic injuries involved prolonged or extended onset, while acute-on-chronic injuries were increased symptoms of a chronic injury, but were brought about by movements causing rapid onset. the time in the season when the injury occurred was recorded. off-season was defined as that part of the season when no specific cricket practice or training was performed. pre-season was that part of the season when specific cricket practice and training was undertaken before the commencement of matches. season was defined as that part of the season where matches were played and included international tours. 5 injury incidence refers to the number of injuries occurring during the season, while injury prevalence is the average percentage of players who are not available for selection for a match. 5 one of the limitations of this study was that it does not include the few 20/20 over competitions and the afro-asian cup competitions during this period. further, the effect of any south african players in the domestic competition was not included here as it has been included in a study on provincial players over the similar period. 7 the bmdp statistical software package (bmdp, 1993, los angeles, bmdp statistical software inc.) was used to compute descriptive statistics. the chi-square test of independence was used to determine whether injury prevalence is related to home and away status. results one hundred and thirteen injuries were recorded by 36 south african players over the two-season period. the injuries were evenly spread across both seasons (s1=56 and s2=57) and resulted in 39 matches being missed by players. the number of matches played from s1 (37) to s2 (33), regardless of format or venue, remained fairly consistent (table i). the majority of the injuries were first-time (77%) and acute (86%) injuries in s1, with similar results found in s2 (75% and 88%, respectively). the number of recurring injuries from the previous season increased slightly from s1 (9%) to s2 (11%) and was table i. number of matches played and missed s1 s2 st # % # % # % matches played (#) odi home & away 22 100 22 100 44 100 home 12 55 10 46 22 50 away 10 46 12 55 22 50 test home & away 15 100 11 100 26 100 home 7 47 6 55 13 50 away 8 53 5 46 13 50 total home & away 37 100 33 100 70 100 home 19 51 16 49 35 50 away 18 49 17 52 35 50 matches missed (#) 17 44 22 56 39 100 injuries (#) 56 50 57 50 113 100 s1 2004 2005 season. s2 2005 2006 season. st 2004 2005 and 2005 2006 seasons. # number. accompanied by a slight increase in acute-on-chronic injuries from 11% to 12% (table ii). the injuries primarily occurred during matches (63%) in s1, with the balance occurring as a result of practices (20%), during practices and matches (14%) and training (7%). however, there were fewer injuries that occurred during matches (49%) in s2, with an increased occurrence in practices (21%), gradual onset (23%) and training (7%). the majority of injuries occurred during test matches (43%), practice (20%) or were of gradual onset (19%) (table ii). the regional distribution of the injuries indicates that these were mainly to the lower limbs (s1 – 43%; s2 – 37%; st – 40%). however, there was a substantial increase in other injuries or illnesses, such as upper-throat respiratory tract infections, gastrointestinal infection and infection, from s1 (16%) to s2 (30%) (table iii). table ii. injury occurrence s1 s2 st # % # % # % first time 43 77 43 75 86 76 recurring previous season present season 5 8 9 14 6 8 11 14 11 16 10 14 acute 48 86 50 88 98 87 chronic acute-on-chronic 2 6 3 11 0 7 0 12 2 13 2 11 injury occurrence matches 50-over test practice gradual onset training 5 30 11 8 2 8 54 20 14 4 10 18 12 13 4 17 32 21 23 7 15 48 23 21 6 13 43 20 19 5 s1 2004 2005 season. s2 2005 2006 season. st 2004 2005 and 2005 2006 seasons. # number. table iii. regional distribution and diagnosis of injuries s1 s2 st # % # % # % regional distribution head & neck upper limb back & trunk lower limb other 4 12 7 24 9 7 21 13 43 16 13 6 21 17 0 23 10 37 30 4 25 13 45 26 4 22 11 40 23 diagnosis haematomas acute sprains tendinopathy muscle strains other trauma joint inflammation other injuries 11 3 2 8 11 5 16 20 5 3 14 20 9 29 5 7 6 9 18 5 7 9 12 10 16 32 9 12 16 10 8 17 29 10 23 14 9 7 15 26 9 20 total 56 100 57 100 113 100 s1 2004 2005 season. s2 2005 2006 season. st 2004 2005 and 2005 2006 seasons. # number. table iv. injuries per activity and mechanism s1 s2 st # % # % # % batting 13 23 13 23 26 23 impact by ball batting – overuse other 11 2 6 7 17 7 2 bowling 19 34 11 19 30 27 delivery stride over-bowling bowling other 1 6 4 8 3 7 1 1 9 11 9 fielding 14 25 13 23 27 24 sliding for ball running to field ball impact by ball catching a ball throwing other 4 1 5 2 2 1 1 2 1 1 7 5 2 7 3 1 9 fitness 1 2 2 4 3 3 touch rugby other 1 1 1 2 1 other 9 16 18 32 27 24 illness other 8 1 17 1 25 2 total 56 100 57 100 113 100 s1 2004 2005 season. s2 2005 2006 season. st 2004 2005 and 2005 2006 seasons. # number. sajsm vol 23 no. 2 2011 47 the major injury categories in s1 were haematomas (20%), other trauma (20%) and muscle strains (14%). however, the results were more evenly spread for s2, with the major injury categories being muscle strains (16%), acute sprains (12%) and tendinopathies (10%). a large increase in other trauma was reported from s1 (20%) to s2 (32%) (table iii). in s1 the majority of injuries occurred while bowling (34%), fielding (25%) and batting (23%). in s2 the injuries were distributed more evenly among fielding (23%), batting (23%) and bowling (19%). the mechanisms for injury were mainly impact when batting (n=17) and fielding (n=7), bowling and bowling for long periods (n=20) and illness (n=25) (table iv). more injuries occurred during the first half of the season (october december) than the second half (january march) (table v). the match exposure time of odi and test matches was 1 906 h and 5 070 h, respectively, with a total match exposure time of 6 976 h (table vi). the odi injury prevalence was higher for away matches (5%) than home matches (2%). similar results were found for the test injury prevalence, with away matches (6%) producing more missed matches than home matches (2%). the total injury prevalence was higher for away matches (6%) than home matches (2%), showing a moderate practical significant difference (chi-square (1)=5.13, p=0 .023, v=0.07, and increased slightly from s1 (3%) to s2 (4%). the injury prevalence was higher in test (4.2%) than odi (3.5%) in both home (test: 2.2% and odi: 1.8%) and away (test: 6.2% and odi: 5.2%) matches. the match injury incidence of odi and test matches was 79 and 95 injuries/10 000 h, respectively, with a total match injury incidence of 90 (table vi). no home and away injury incidence could be calculated. discussion the first important finding was that the injury prevalence was greater in test (4.2%) than odi (3.5%) matches. when compared with the west indian and australian study, the south african injury prevalence was less than in the west indian and australian test (11.3% and 7.0%, respectively) and odi (8.1% and 10.0%, respectively) table v. injuries per month s1 s2 st # % # % # % pre-season august september season 56 100 44 77 100 89 october november december january february march 1 19 12 7 5 12 16 11 6 1 10 1 35 23 13 6 22 off-season 0 0 13 23 13 11 april may june july 1 12 1 12 total 56 100 57 100 113 100 s1 2004 2005 season. s2 2005 2006 season. st 2004 2005 and 2005 2006 seasons. # number. table vi. exposure time, injury prevalence and incidence s1 s2 st exposure time (h) odi home away total 520 433 953 433 520 953 953 953 1 906 test home away total 1 365 1 560 2 925 1 170 975 2 145 2 535 2 535 5 070 total home away total 1 885 1 993 3 878 1 603 1 495 3 098 3 488 3 488 6 976 injury prevalence (% per match) odi home & away home away 2.5 2.2 2.9 4.5 1.3 7.2 3.5 1.8 5.2 test home & away home away 4.2 2.2 6.0 4.1 2.2 6.4 4.2 2.2 6.2 total home & away home away 3.2 2.2 4.3 4.4 1.6 7.0 3.8 2.0 5.6 injury incidence (injuries/10 000 h) odi test total 53 101 90 105 84 90 79 95 90 s1 2004 2005 season. s2 2005 2006 season. st 2004 2005 and 2005 2006 seasons. 48 sajsm vol 23 no. 2 2011 matches. a possible explanation for this is that the west indian and australian studies were conducted over only one season, with the possibility of one serious injury requiring surgery and a long-term layoff having a greater effect on the injury prevalence. the second important finding was that the south african match injury incidence for test (95/10 000 h) and odi (79/10 000 h) matches was significantly higher than that of the west indian and australian test (48.7 and 23.1 injuries/10 000 h, respectively) and odi (40.6 and 38.5 injuries/10 000 h, respectively) injury incidence. 4 in the current study no practice or fitness exposure time was recorded for the south african cricketers, which would greatly influence injury incidence as seen by the south african provincial cricketers. 8 further, the south african cricketers had more match exposure time compared with that of the west indian and australian studies. a large number of injuries were first-time injuries of an acute nature, which included impact injuries, particularly when batting, resulting in haematomas and other trauma injuries. however, there was an increase in recurring injuries from the previous season, which was accompanied by an increase in acute-on-chronic injuries, with the majority of the injuries being muscle strains, tendinopathies and acute sprains. the abovementioned could have been the result of the players returning to play without being fully rehabilitated and the nature of the injury sustained. when playing international cricket, test matches are generally scheduled to be played first in the series before the odis, which could explain the increased number of injuries during the early part of the season regardless of home and away matches. however, the increased number of injuries towards the end of the season could be due to the south african end-of-year tours. during the longer version of the game the players tend to be relatively inactive for long periods of time before rapidly moving after the ball when fielding. bowlers may be required to bowl multiple spells, sometimes accumulating more than 20 overs in a day compared with four ten over spells in limited over cricket. this could have resulted in the large number of injuries that occurred during fielding and bowling, particularly during test cricket. similar results were found with the south african provincial players. 7 the primary mechanisms of injury were bowling, sliding for and impact by the ball when fielding. similar results were found where many of the west indian injuries were muscle strains caused by running after and picking up the ball and injuries to young fast bowlers. 3 these activities all require some kind of stop-start movement and/or change in direction of the whole body requiring strength, agility and flexibility. in sports involving bouncing and jumping activities, with a high intensity of a stretch-shortening cycle, a stretching programme significantly influenced the viscosity of the tendons, making them more compliant, and stretching may be beneficial for injury prevention. 7 for both odi and test matches the injury prevalence showed a practical significant greater difference for away than home matches, which was similar to the west indian study. 4 the possible reason could be multifactorial and could include factors such as unfamiliar climate and underfoot conditions, different food and beverage intake, amount of time before receiving medical treatment, particularly in the case of illnesses such as upper-throat respiratory tract infections, gastrointestinal infection and infection. a second report on west indian cricket has shown a decrease in the number of away injuries over the past five years as a result of a physiotherapist and a structured medical panel overseeing the management of injuries when on tour, 9 which appears now to be standard practice with all the touring teams of the major cricketplaying nations. conclusion injury surveillance is the fundamental process behind successful injury prevention and should be carried out on an on-going long-term basis using the internationally accepted injury surveillance method for the reporting of injuries at all levels of south african cricket. the study provided prospective injury incidence and prevalence data for south african cricketers playing at international level over a two-season period, highlighting the increased injury prevalence for away matches and an increased match injury incidence for test and odi matches, possibly as a result of increased match exposure time. references 1. leary t, white j. acute injury incidence in professional county cricket players (1985-1995). br j sports med 2000;34:145-147. 2. stretch ra, venter djl. cricket injuries – a longitudinal study of the nature of injuries to south african cricketers. sa j sports med 2005;17(3):4-9. 3. orchard j, james t, alcott e. injuries in australian cricket at first class level 1995/1996 to 2000/2001. br j sports med 2002;36:270-275. 4. mansingh a, harper l, headley s, king-mowatt j, mansingh g. injuries in west indian cricket 2003-2004. br j sports med 2006;40:119-123. 5. orchard j, newman d, stretch r, frost w, mansingh a, leipus a. methods for injury surveillance in international cricket. j sc med sport 2005;8(1):1-14. 6. orchard j. orchard sports injuries classification system (osics). in: bloomfield j, ficker p, fitch k, eds. science and medicine in sport. 2nd ed. melbourne: blackwell, 1995:674-681. 7. stretch r, raffan rp, allan n. injury patterns of south african provincial cricket players over a two season period. sa j sports med 2009;21(4):151-155. 8. witvrouw e, mahieu n, danneels l, mcnair p. stretching and injury prevention: an obscure relationship. j sports med 2004;34(7):443-449. 9. mansingh a. injuries in west indies cricket: has there been a change in the last five years? 4th world congress on science and medicine in cricket, chandigarh, india 2011. sajsm vol 23 no. 2 2011 49 sajsm 514.indd original research 12 sajsm vol. 27 no. 1 2015 background. association football, otherwise known as soccer, is the most popular sport in the world. the increase in the popularity of the game and the expectations from players make injury risk in football high. objective. to describe the types, severity, prevalence and mechanism of injuries among professional footballers in the nigeria premier league (npl). methods. the union of european football association (uefa) injury study questionnaire was used for data collection. a total of 240 footballers from 11 clubs, who participated in the 2011/2012 npl premiership season, was selected through proportionate stratified random sampling technique, and the participants were studied using a prospective cohort study design for 6 months. descriptive statistics of means, percentages and frequency distributions were used to answer the research questions. results. the mean (standard deviation) age, height and weight of the injured footballers was 22.9 (3.4) years, 1.69 (0.05) m and 71.3 (3.9) kg, respectively. there was a high injury prevalence (78%) associated with actual league games, whereas the incidence rate per 1 000-hour exposure was 300.2 exposure-hours from 19 games within 6 months. sprain (32%) was the predominant type of injury recorded. the tackle event (34%) was the predominant mechanism of injury recorded, and 63% of the injuries led to 1 3 days of player absence from football activities. most of the injuries were recurrent injuries (63%). conclusion. this study showed a high occurrence of injuries in the npl, in particular associated with league (competitive) games. the findings of this study will serve to guide the development and implementation of injury prevention strategies in the npl. s afr j sports med 2015;27(1):12-15. doi:10.7196/sajsm.514 the uefa model in identification of types, severity and mechanism of injuries among professional footballers in the nigerian premier league u k ani,1 msc; p o ibikunle,2,3 phd; c o akosile,3 phd; u useh,2 phd 1 physiotherapy department, college of health sciences, babcock university teaching hospital, ilisan-remo, nigeria 2 school of research and postgraduate studies, faculty of agriculture, science and technology, north-west university, mafikeng, south africa 3 department of medical rehabilitation, faculty of health sciences and technology, nnamdi azikiwe university, nnewi, nigeria corresponding author: p o ibikunle (po.ibikunle@unizik.edu.ng) association football, or soccer, is the most popular sport in the world, played by ~265 million footballers. [1] in africa, football is governed by confederation of african football (caf), an organisation that was formed in 1957 by four founding members – egypt, sudan, ethiopia and south africa – to administer and organise football activities on the continent. football started in nigeria in the early 1900s, and was introduced by baron mulford, who organised weekly matches between european and nigerian youths in lagos.[2] the nigerian football association (nfa) was established in 1945 with the governor’s cup, which later became known as the football association (fa) cup – the major national domestic football competition.[2,3] in 1972, the national league was formed with six teams, and in 1990, at onikan stadium in lagos state, the professional league was launched, with 16 clubs from around the country.[2,4] today, the nigeria premier league (npl) is the highest level of domestic nigerian football, organised and managed by the nigeria professional league board (nplb). [3] the npl is ranked above two first-division groups: the nigeria division 1-a and nigeria division 1-b.[2] football is associated with a variety of injuries and a high injury incidence rate. these factors are primarily due to the popularity of the game and the performance-related pressure placed on the players.[5] a football injury is a physical complaint sustained by a player during competition or training, preventing the player from participating in competition or training activities for one or more days thereafter.[6,7] injuries sustained in football are due to a combination of factors (intrinsic and extrinsic). these include the nature of the sporting environment, equipment and rules, and the unique physical characteristic of the footballers, such as structural imbalances and age.[8] sports injuries are expected consequences of competitions and are not usually as a result of a single causative factor, but are instead associated with various factors interacting at a given time.[9] types of injury classifications may also depend on anatomical structures and the specific areas involved, including musculoskeletal, neurological and lower-back injuries. the musculoskeletal classification may involve skeletal muscles, joints, tendons and ligaments. musculoskeletal injuries constitute the largest class of injuries sustained in sport. based on previous epidemiological injury research, the severity of an injury may be categorised into mild, moderate, major, sportsdisabling and catastrophic.[9] a recent epidemiological study of football injuries in benin city, nigeria, showed an ~82% injury prevalence rate among footballers.[5] studies using video analysis to compare injury prevalence between nigerian and english professional soccer leagues have found that the npl had a higher occurrence of injuries than the english premier league.[5,10] there is a lack of injury sajsm vol. 27 no. 1 2015 13 epidemiological research on professional nigerian footballer cohorts, and furthermore, there are inconsistencies in the way injuries are reported.[5] the uefa model/guideline is a policy model and a practical guideline for conducting epidemiological studies of football injuries, and was designed to correct the inconsistent manner in which epidemiological studies were conducted in football.[11] these inconsistencies include football injury definitions that differ between studies, and varying research designs that make data comparison difficult.[11] the model states that a football injury study should have a prospective cohort design, and that the study should cover both training and competition sessions. the model also stipulates that information about football injuries should include date of injury, date of return to football activities, injury types, location of injury, mechanism of injury and a measure of severity. in the guideline, injury severity is categorised as slight (1 3 days’ absence), minor (4 7 days), moderate (8 28 days), and major (>28 days). in addition, the model stipulates that only injuries occurring during scheduled team activities should be included in the statistics, while injuries that occurred during leisure time or from participating in other sports (outside team training or matches), and absence as a result thereof, should not be included.[6] it is evident that in the npl, there is a paucity of information on the injury profile of the footballers and that there is no comprehensive database for injuries in the league.[5,10] this may limit the opportunity for the design and implementation of targeted injury prevention strategies, and may inhibit the growth and development of the game in nigeria. these inconsistencies have made it difficult to meaningfully compare published studies on types, severity and mechanisms of injury, and injury prevalence. the objectives of this study were to determine among professional footballers in the npl: (i) the prevalence rate of injuries; (ii) the predominant types of injuries; (iii) the severity of injuries; and (iv) the incidence rate of injuries during matches (expressed as per 1 000 match player-hours). methodology research design this study was a prospective cohort survey. professional league players were prospectively monitored for a period of 6 months. population the target population of the study was 600 professional footballers from 20 clubs (30 players per club), who participated in the 2011/2012 npl season. sample size a total of 240 players constituted the sample. they were randomly selected from 11 clubs of 30 registered players each. the sample size was statistically determined using the taro yamane formula for a finite population.[12] sampling technique proportionate stratified random sampling was used for this study (table 1). instrument for data collection the uefa injury study questionnaire was used for data collection. the instrument has a reliability coefficient of 0.80 and a validity coefficient of 0.89. the questionnaire has 17 categories of questions. information collected from the footballers included anthropometric data, exposure types, game situations, training/match surfaces, injury types, injury locations, mechanisms of injury, injury severity and referee sanctions. the instrument was interpreted by coding each item with arabic numerals and the frequency of each categorical variable was calculated. method/procedures of data collection ethical approval for the study was sought and obtained from the university teaching hospital ethical committee. the 2011/12 npl season was studied for 6 months. club officials and medical personnel were recruited and trained at participating clubs to serve as research assistants. the purpose, procedures and ethical components of the research were also fully explained to the participants. the research assistants and the researchers distributed the questionnaires to the clubs. the players completed the forms after relevant explanations/instructions by the researchers and trained research assistants. where this was not possible, the research assistants administered the questionnaire to the footballers. the researchers were in contact with the clubs and research assistants telephonically, and received completed questionnaires either by physically collecting them at each club or via mail at the end of each month. injury cards/questionnaires were mailed to the study group on the last day of every month. definition of injury an injury was defined as any event occurring during a scheduled training session or a match, resulting in the player leaving that session/ match or missing a subsequent session/match. recurrent injury was defined as any event occurring during a scheduled training session or match in sequel to an injury that was not adequately rehabilitated, resulting in the player leaving that session/match or missing a subsequent session/match. absence from training sessions and matches due to injury were reported on the attendance record and an injury report form was completed. severity of injuries and illnesses the severity of an injury or illness episode was evaluated by the length of absence from football participation. rehabilitation a player was considered rehabilitated if he could fully participate in all aspects of collective training (table 2). the player was considered fully rehabilitated once the medical team had cleared him for full participation in team training and availability for match selection. table 1. regional distribution and selection of professional league clubs geopolitical region clubs, n population of players, n selected clubs based on sampling, n sample size, n south-west 3 90 2 36 south-east 3 90 2 36 south-south 5 150 2 60 north-east 2 60 1 24 north-central 4 120 2 48 north-west 3 90 2 36 total 20 600 11 240 14 sajsm vol. 27 no. 1 2015 confidentiality all personal data were confidential. the names of all the players involved in the study were replaced by codes before computerising. the contact person in each club replaced the names of individual players with a code and deleted the players’ names before sending the forms to the investigators. method of data analysis descriptive statistics of means, standard deviation (sds) and frequencies were used as statistical tools to describe the footballers’ anthropometric characteristics and other variables. percentages and frequencies were used to answer the research questions. the prevalence rate was extrapolated using the following formula: prevalence = number of injuries recorded/ sample size × 100 the following formula was used to calculate the incident rate/1 000 hours of player exposure:[13] match-related injury incidence = [number of injuries × 1 000]/[player exposure hours] incidence rates were described as the number of new injuries in a population at risk over a specified time period, or the number of new injuries during a period divided by the total number of players in that period. results anthropometric characteristics of injured players the mean (sd) age of the injured footballers in this study was 22.9 (3.4) years (range 16 31), and their mean height, body mass and body mass index was 1.69 (0.05) m, 71.3 (3.9) kg, and 24.6 (1.6) kg.m-2, respectively. prevalence rate, type and severity of injuries the prevalence rate of injuries among the professional footballers was 78%, with the predominant type of injury being ligament sprain injuries (32%) (table 3). muscle rupture/tear and tendon injuries constituted 17% and 7% of all the recorded injuries, respectively. haematoma/contusion/bruises accounted for 6% of the injuries, while synovitis /effusion, overuse symptoms, abrasion and lacerations each accounted for 4% of injuries. overall, 63% of the injuries sustained were of a ‘slight’ severity, resulting in 1 3 days’ absence from team football activities. severe injuries (>28 days lost) constituted 14% of injuries, while moderate injuries (8 28 days’ absence from football activities) and minor injuries (4 7 days’ absence) constituted 14% and 9%, respectively. frequency of injuries occurring during different activities most of the injuries occurred during matches (49%) and practices (38%) (table 2). distribution of injuries according to mechanisms, playing surfaces and recurrent injury incidences tackle events (34%) and falling/diving (8%) were the predominant injury mechanisms (table 4). other injury mechanisms included running/sprinting and stretching, acc oun ting for 7% each, and twisting/ turning and sliding, which accounted for 6% each. about 69% of injuries occurred while playing on grass surface, 28% on an artificial surface, and 3% on other surfaces. approximately 37% of all the injuries were recurrent injuries, which affected the same body parts, while 63% of the injuries were first-time injuries. calculation of risk of injury a total of 187 injuries were recorded. there were 22 players per match and 19 matches during the study period. the average match duration was 1.49 hours. therefore, the exposure time during matches was calculated as: 22 players × 19 games × 1.49 playing hours = 622.82 player exposure hours therefore, the risk during matches was calculated as: (187 injuries/622.82 player exposure hours) × 1 000 = 300.2 injuries/1 000 player-hours discussion this study revealed an injury prevalence rate of 78% among professional footballers in the npl. this result is consistent with the findings of other authors,[5,10] who found sports injury prevalence rates of 68% and 82%, respectively, among the footballers in table 3. types of injury n (%) sprain 60 (32) muscle rupture/tear 33 (17) others 16 (9) tendon injury/tendonosis 13 (7) haematoma/contusion/bruises 11 (6) synovitis/effusion 8 (4) overuse symptoms 8 (4) dislocation/subluxation 8 (4) abrasion 7 (4) laceration 7 (4) dental injury 7 (4) lesion of meniscus/cartilage 7 (4) fracture 2 (1) other bone injuries 1 (1) total 180 (100)* *percentages are rounded therefore may not total 100 exactly. table 4. mechanism of injury n (%) tackle event 63 (34) falling/diving 14 (8) running/sprinting 13 (7) stretching 13 (7) twisting/turning 12 (6) sliding 12 (6) shooting 11 (6) collision 10 (5) heading 10 (5) jumping/landing 6 (3) blocked 5 (3) dribbling 5 (3) use of arm or elbow 4 (2) hit by ball 4 (2) kicked by other players 3 (2) overuse 2 (1) total 187 (100)* *percentages are rounded therefore may not total 100 exactly. table 2. frequency of injuries occurring during different activities n (%) league match 98 (49) football training 71 (38) friendly match 7 (6) other training 6 (3) national team training 2 (1) reserve/youth team training 3 (2) total 187 (100)* *percentages are rounded therefore may not total 100 exactly. sajsm vol. 27 no. 1 2015 15 npl. however, these findings are in contrast to the findings in some previous studies,[6,9] which found much lower injury prevalence rates in footballers. the difference between our results and the latter might be in the different approaches to winning of the clubs/players, the research methodologies used and the different experience/skills of players who participated in the studies. [14-16] moreover, injured players in the npl were not promptly and properly attended to medically, resulting in increased incidences of recurrent injuries among the players.[5,11] the differences might also be suggestive of the competitive nature of the game, and underscore the need for good officiating/stricter refereeing, adherence to the principle of fair play by the clubs and players, adequate warm-up, safe and effective techniques by the players, and improved coaching techniques on injury prevention. the incidence of injury (300.2 injuries/1 000 player-hours) was relatively higher than those previously recorded in european and american professional footballers.[6,17,18] the finding that there were more injuries in league matches/ competitions (49%) than during training (38%) has been reported before.[5] this can be attributed to the higher intensity of play during matches/competitions compared with training. recurrent injuries constituted 37% of all the injuries recorded in this study. this differs from a previous study, which reported that recurrent injuries constituted ~7% of all injuries.[19] the high rate of recurrent injuries among the players in the npl can be attributed to premature return to football activities after injury, without adequate rehabilitation, or overloading of the players with too many matches. we observed that although most of the clubs studied had masseurs attached to their teams, few clubs had other medical staff, including physiotherapists. this may have resulted in limited rehabilitation regimens within the club, which may have resulted in inadequate rehabilitations after injury. high incidences of previous injury have been reported to be a predisposing factor to future injuries in football.[17-19,20] recent research proposes the need to differentiate between exacerbations and recurrent injuries,[19-22] as this would enable researchers to investigate risk factors for these two types of recurrent injuries separately. this would also determine how well players have been rehabilitated before returning to full participation.[17-19] the data on time loss due to injury showed that ~63% of the injuries were of a slight severity, leading to about 1 3 days’ absence from matches and training, while ~14% of the injuries were severe injuries, leading to ≥28 days’ absence from organised team activities (matches and training). lesser injur y severity has been reported in previous studies.[18] the higher number of days lost to injuries in this study may be attributable to the lack of proper medical attention given to the players when they were injured.[11,17] this study showed that the prevalence of injuries in league matches and football training is 49% and 38%, respectively. it also revealed that tackle events (34%) were the predominant cause of injury in both matches and training. this finding may allude to the aggressiveness of some footballers, as was suggested in a recent study;[22] our study did not formally evaluate the aggression of the npl footballers. however, the frequency of tackle events in soccer compared with other events such as heading or shooting may also be responsible for tackling being a predominant injury mechanism. conclusion this study showed a high occurrence of injuries in the npl, in particular associated with actual league (competitive) games. defenders sustained the most injuries, often from tackle events. this may be a result of attackers being more aggressive in their bid to score goals, to the point of inflicting injuries on the defenders, or that defenders take greater risks to avert goals being scored against their teams. the findings of this study will serve to guide the development and implementation of injury prevention strategies in the npl. references 1. fédération internationale de football association. big count. http://www.fifa.com/ worldfootball/bigcount/index.html (accessed 30 january 2014). 2. rahama aa. nigeria national league. http://www.nigerianationalleague.com/aboutthe-league (accessed 30 may 2013). 3. online nigeria. history of sport in nigeria. http://www.onlinenigeria.com/sport (accessed 4 march 2015). 4. schöggl h. nigeria 1972 1979. http://www.rsssf.com/tablesn/nig72.html (accessed 18 january 2012). 5. azubuike so, okojie oh. an epidemiological study of football (soccer) injuries in benin city, nigeria. br j sports med 2009;43(5):382-386. [http:/dx.doi.org/10.1136/bjsm.2008.051565] 6. hägglund m, walden m, ekstrand, j. injury prediction in professional football. abstract, first world congress of sports injury prevention. br j sports med 2005;39(6):375-408. 7. fuller cw, randall wd, corllette j, schmalz r. comparison of the incidences, nature and cause of injuries sustained on grass and new generation artificial turf by male and female football players. part 2: training injuries. br j sports med 2007;41(suppl 1):27-32. [http://dx.doi.org/10.1136/bjsm.2007.037267] 8. hootman jm. epidemiology of musculoskeletal injuries among sedentary and physically active adults. med sci sports exerc 2002;34(5):838-844. [http://dx.doi. org/10.1097/00005768-200205000-00017] 9. hägglund m, walden m, bahr r, ekstrand j. methods for epidemiological study of injuries to professional football players: developing the uefa model. br j sports med 2005;39(6):340-346. [http://dx.doi.org/10.1136/bjsm.2005.018267] 10. akinbo sr, salau ma, odebiyi do, ibeabuchi nm. video analysis of musculoskeletal injuries in nigeria and english professional soccer leagues. niger j health biomed sci 2007;6(2):85-89. 11. ekstrand j, vogel u. euro 2004 injury study. abstract, first world congress of sports injury prevention. br j sports med 2004;39(6):373-408. 12. uzoagulu ae. practical guide to writing research project reports in tertiary institutions. enugu: cheston ltd, 2011. 13. philips lh. sports injury incidence. br j sports med 2000;34(2):133-136. [http:// dx.doi.org/10.11.36/bjsm.34.2.133] 14. faude o, junge a, kindermann w. injuries in elite female soccer players. abstract, first world congress of sports injury prevention. br j sports med 2005;39(6):375408. 15. emery ca, meeuwisse wh, hartmann s. risk factors for injury in adolescent soccer: implementation and validation of an injury surveillance system. abstract, first world congress of sports injury prevention. br j sports med 2005;39(6):375-408. 16. junge a, rösch d, peterson l, graf-baumann t, dvorak j. prevention of soccer injuries: a prospective intervention study in youth armature players. am j sports med 2002;30(5):652-659. 17. dvorak j, junge a, derman w, schwellnus m. injuries and illnesses of football players during the 2010 fifa world cup. br j sports med 2011;45(8):626-630. [http://dx.doi. org/10.1136/bjsm.2010.079905] 18. ekstrand j, gillquist j, möller m, oberg b, liljedahl so. incidences of soccer injuries and their relation to training and team success. am j sports med 1983;11(2):63-67. [http://dx.doi.org/10.1177/036354658301100203] 19. meeuwisse wh. assessing causation in sport injury: a multifactorial approach. clin j sport med 1999;4(3):166-170. [http://dx.doi.org/10.1097/00042752-19940700000004] 20. hawkins d, metheny j. overuse injuries in youth sports: biomechanical considerations. med sci sports exerc 2007;33(10):1701-1707. [http://dx.doi. org/10.1097/00005768-200110000-00014] 21. fuller cw, smith gl, junge a, dvorak j. the influence of tackle parameters on the propensity for injury in international football. am j sports med 2004;32(suppl 1):4353. [http://dx.doi.org/10.1177/036354650326128] 22. williams s, trewartha g, kemp s, stokes k. a meta-analysis of injuries in senior men’s professional rugby union. sports med 2013;43(10):1043-1055. [http://dx.doi. org/10.1007/s40279-013-0078-1] original research sajsm vol 23 no. 4 2011 111 introduction the benefits of regularly participating in physical activity, through casual or organised activities or programmes, seeking to improve fitness, mental well-being and social relationships, are well recognised. 1 physically inactive lifestyles present a major health problem to the populations of developed and developing nations, contributing to chronic diseases and psychological distress. 2 although young people are more physically active than adults, the worldwide increase in overweight among youth has raised concerns about the adequacy of habitual activity levels among children and adolescents. the centers for disease control and prevention reported in 2000 that nearly half of american youth aged 12 21 years are not vigorously active on a regular basis. 3 further, youth become increasingly less active as grades in school increases, with the most dramatic declines occurring during adolescence (ages 15 19 years) and young adulthood (ages 20 25 years). 4 even in adolescence, 5 in the transition to university, and more specifically during the period of study at university, there is a decrease in the practice of moderate to vigorous physical activity. 6 irwin, 7 in his systematic review on participation in physical activity amongst university students (19 studies from 27 countries, not including egypt) concluded that less than one-half of university students in usa and canada were sufficiently active to gain a health benefit. also musharrafieh et al. 8 found that 26.4% of university students in lebanon engaged in regular physical exercise. conversely, abdullah et al. 9 found that two-thirds of chinese university students were physically active. in 2011, the american college health association 10 reported that college students as a population are physically inactive, with only 20% reporting participation in moderate physical activity and 30% in vigorous physical activity on a regular basis from 2008 to 2010 with slight variation over years. in egypt, the only available study of physical activity among university students was done by abolfotouh et al. 11 this study was conducted among 600 students attending alexandria university hostels and reported that 33.8% of the studied sample were physically inactive. barriers to physical activity have been examined across a variety of populations. although findings revealed that as barriers increased, physical activity decreased in youth and adult populations, the findings have been inconsistent in adolescent populations. 12 body consciousness has been shown to be a barrier for female adolescents in the general population. 13 lack of time has been the greatest obstacle to physical activity in adolescent students. 14 also the weather, class assignments and the lack of interest or just the desire to do any other activity, have been among the most commonly mentioned barriers to physical activity by university students in the study carried by sanz and ponce. 15 the lack of social and institutional support, as well as the physical environment, were the main barriers found by gyurcsik et al. 16 the aim of our study was to describe the pattern of vigorous physical activity among egyptian freshmen university students and to evaluate the association between physical activity, abstract objectives. to highlight the pattern of vigorous physical activity among freshmen university students and to evaluate the association between sociodemographic factors, perceived barriers, support factors, sedentary behaviours and body mass index. methods. a cross-sectional study was conducted on mansoura university students at the beginning of the academic year 2008 2009. a total of 500 freshmen students were selected by systematic random sample. participants responded to the short form of international physical activity questionnaire and other questions. results. the study revealed that the prevalence of vigorous activity among the students was 9.8% (n=49) versus 90.2% (n=451) for mild and moderate activity. body-related barriers were significantly higher among those reporting mild and moderate activities as shyness from others when doing exercise (6.9% versus 0.0%) and shyness from body looks in front of people (14.6% versus 4.1%). lack of equipment was also perceived to be a barrier (31.0% versus 16.3%), for those doing mild to moderate versus vigorous, respectively. a significantly higher proportion of persons doing vigorous activity reported the influence of support factors such as perceived benefit for health (53.1% versus 33.7%), encouragement from others (53.1% versus 30.4%) and participation from others (51.0% versus 23.9%), compared with the more sedentary students. the majority of both groups spent <4 hours daily in front of a computer, but the overall proportion was significantly higher among those only reporting mild and moderate activity (88.0% versus 63.3%). conclusion. the prevalence of most of the barriers studied was higher among those reporting mild and moderate activities and support factors were higher among those reporting vigorous activity. these results highlight the importance of environmental factors, social norms and intra-personal factors in determining the pattern of activity among egyptian freshmen university students. nadia abd el-hamed montasser1 (md) abdel-hady el-gilany abd elfattah2 (md) randah mohamad helal3 (md) 1 professor of public health, department of community medicine, college of medicine, mansoura university, egypt 2 professor of public health, department of community medicine, college of medicine, mansoura university, egypt 3 lecturer of public health, department of community medicine, college of medicine, mansoura university, egypt correspondence to: randah mohamad helal (ranhel2000@yahoo.com) pattern of vigorous physical activity among egyptian freshmen university students 112 sajsm vol 23 no. 4 2011 sociodemographic determinants, barriers, support factors, sedentary behaviours and bmi. methods locality the study was carried out in mansoura university, egypt during the beginning of the academic year 2008 2009. mansoura university was founded in 1972 in mansoura city, egypt and is one of the biggest public egyptian universities. the main campus is located in mansoura city. it comprises 13 faculties: medicine, education, science, pharmacy, dentistry, commerce, law, engineering, agriculture, nursing, veterinary medicine, physical education; as well as computer science and information systems. four faculties are located off campus, namely arts, special education, tourism and hotels, and kindergartens. population the target population included newly attending students (freshmen) of the practical sectors in mansoura university (practical faculties of medicine, pharmacy, nursing, veterinary medicine, dentistry and the other practical faculties such as science, agriculture, computer and information, engineering), attending a routine medical checkup that is done for the first-year students in the university. the practical sectors were chosen as they were more accessible, and as first years, the students still live with their families. they represent different geographical and socio-economic strata of the community. the pattern of physical activity studied reflects physical activity during vacation time (not during the academic year). most of these students would make use of public transportation, with a minority having access to private cars. sample size determination there are approximately 6 000 first-year students. we based our sample size on an expected prevalence for vigorous physical activity in arab young adults of 11.3%, previously reported by al-hazzaa. 17 using epi-info version 6 with 11.3% as the expected prevalence, and 8.5% as the minimal prevalence, we estimated that we would require a sample of at least 454 subjects, and increased this to 500 to be more representative. the students were selected according to a systematic sampling strategy, one in every 11 students. measures and data management demographic attributes, different forms of activity, barriers, support factors and other sedentary behaviours were assessed using a selfadministered questionnaire presented in arabic languages after obtaining oral consent from the participants. participants reported their age, gender and residence. socio-economic variables 18 included parents’ education and occupations, per capita monthly income in egyptian pounds, family size, crowding index, and presence of audiovisual sets. participants self-reported their frequency and duration of their physical activity during the previous week using the short form international physical activity questionnaire. 19 physical activity was classified as follows: • low ─ no activity is reported or some activity is reported but not enough to meet physical activity levels 2 or 3 • moderate ─ any of the following 3 criteria: 3 or more days of vigorous activity of at least 20 minutes per day or 5 or more days of moderate-intensity activity and/or walking of at least 30 minutes per day or 5 or more days of any combination of walking, moderate or vigorous intensity activities achieving a minimum of at least 600 met (metabolic equivalent)minutes/week • high ─ any one of the following 2 criteria: vigorous-intensity activity on at least 3 days and accumulating at least 1 500 met-minutes/week or 7 or more days of any combination of walking, moderate-vigorous intensity activities accumulating at least 3 000 met-minutes/week. one met is the energy (oxygen) used by the body as a person sits quietly, perhaps while talking on the phone or reading a book. met-minute/week is computed by multiplying the met score of an activity by the minutes performed. the met score differs according to the activity, for example walking = 3.3 mets, for moderate physical activity = 4.0 mets and for vigorous activity = 8.0 mets. we obtained measures of height and weight. height measurements were to the nearest 0.5 cm without shoes and weight was measured to the nearest 0.1 kg with light clothes. body mass index (bmi) was calculated as weight in kilograms divided by heightin meters squared. individuals with a bmi <18.5 are considered underweight, those with bmi of 18.5 24.9 are considered normal table i. general demographic and behavioural characteristics of the studied group studied group characters n % sociodemographic characteristics gender male 210 42.0% female 290 58.5% age (years) mean ± sd 17.7 ± 0.7 residence urban 305 60.6% rural 197 39.4% socioeconomic standard high 331 66.2% middle 155 31.0% low 14 2.8% activity pattern practised vigorous activity 49 9.8% practised mild and moderate activity 451 90.2% bmi underweight 17 3.4% normal weight 311 62.2% overweight 112 22.4% obese 60 12.0% sedentary behaviour tv watching <4h 369 73.8% ≥4h 131 26.2% computer use <4h 428 85.6% ≥4h 72 14.4% music hearing 139 27.8% sleep hours <8h 428 85.6% ≥8h 72 14.4% sajsm vol 23 no. 4 2011 113 weight, individuals with bmi of 25 29.9 are considered overweight, while individuals with a bmi of 30 or more are considered obese. 20 barriers and support factors to physical activity data on barriers to and factors in support of physical activity were collected. these were grouped according to whether they were related to physical limitations, convenience, available resource, social factors, and fitness-related issues. participants also reported the total hours they spent watching television, playing video games, in front of computers or using the internet and if they prefer listening to music during studying lessons. statistics a nested case-control study was carried out between students with mild/moderate activity and those with vigorous activity. the completed questionnaires were subjected to revision and the collected data were coded, processed and analysed through spss (statistical package for social sciences) (standard version release 16.0).the chi-square and fisher’s exact tests were used for testing significance of categorical data, as appropriate. student’s t-test was used for continuous data as age. the significance level was considered at p≤0.05. results table i presents the characteristics of the sample, 42.0% of whom were male and 58.0% of whom were female, with a mean age of 17.7±0.7 years. about two-thirds of studied groups were from urban areas and had high socio-economic status. only 9.8% (n=49) of the students practised vigorous activity but 62.2% of the students had table ii. distribution of the studied group physical activity according to their personal, social, behavioural characteristics and their bmi test of sig. physical activity studied group social and personal characters vigorous n=49 n % mild and moderate n=451 n % gender **p=0.003 14.3%30 85.7%180male 6.6%19 93.4%271female age (years) ***p=0.6417.7 ± 0.7717.7 ± 0.69mean ± sd residence **p=0.035 11.9%36 88.1%267urban 6.6%13 93.4%184rural socio-economic standard 12.4%41 87.6%290high *p=0.0113.9%6 96.1%149middle 14.3%2 85.7%12low different forms of sedentary behaviours tv watching *p=0.54 73.5%3673.8%333<4h 26.5%1326.2%118≥4h computer use *p=0.000 63.3%3188.0%397<4h 36.7%1812.0%54≥ h *p=0.4926.5%1327.9%126music hearing sleep hours *p=0.41 83.7%4185.8%387<8h 16.3%814.2%64≥8h bmi *p=0.37 2.0%13.5%16underweight 73.5 %3661.0%275normal weight 14.3%723.3%105overweight 10.2%512.2%55obese # the faculties of the students not included in the analysis as the pattern of study in these faculties have no effect yet. *chi-square (χ2). ** fisher’s exact test. *** t-test. 114 sajsm vol 23 no. 4 2011 normal bmi, 26.2% (n=131) spent more than 4 hours in front of the television but only 14.4% (n=72) spent more than 4 hours in front of the computer. also 14.4% (n=72) of the studied group slept more than 8 hours per day and 27.8% (n=139) preferred listening to music. as shown in table ii, the age of the sample ranged between 17 and 20 years, with a mean age of (17.7±0.7 years), with slight differences between groups. only 6.6% of the women reported vigorous activity compared with 14.3% of men. vigorous activity was more prevalent among urban inhabitants (11.9%) than rural ones (6.6%) (p=0.035). however, a nearly equal prevalence of vigorous activity was reported among low and high social class but much lower rates were reported among middle social class (p=0.011). by studying the sedentary behaviours, it was found that the only significant difference between groups was for computer use, which was higher among those reporting only mild and moderate activity. for the rest of sedentary behaviours no significant differences were detected. although no significant difference was detected between both groups regarding bmi, it was observed that normal-weight students represented the majority among both groups with a higher per cent among the students reporting vigorous activity. overweight and obesity were slightly more prevalent among those reporting only mild and moderate activity. barriers to physical activity are presented in table iii. certain barriers were significantly more common among those reporting only mild and moderate activities such as body-related barriers which included shyness from others when doing exercise (6.9% versus 0.0%) and shyness from body looks in front of people (14.6% versus 4.1%) and one of the resource barriers, which was lack of equipment (31.0% versus 16.3%). other resource barriers, convenience barriers, social barriers and fitness barriers showed no significant differences between groups. however, bad weather and lack of participation by friends were barriers more commonly reported for those students participating in vigorous physical activity. table iv shows the distribution of different support factors for physical activity among the studied groups. those students that engaged in vigorous physical activity more commonly reported perceived benefit for health, encouragement from others and participation from others, as support factors for participation. discussion many young people do not engage in sufficient levels of physical activity to afford the associated health benefits. the 2005 youth risk behavior surveillance survey results indicate that only 36% of american high school students participate in at least 60 minutes per day of physical activity on a regular basis. 21 moreover, recent data from the national health and nutrition examination survey (nhanes) indicate that 33% of american teenagers are unfit and that this is setting the stage for health problems later in life. 22 the results of the present study showed that only 9.8% of the students practised vigorous activity. nearly equal rates were reported table iii. distribution of the studied group physical activity according to different types of barriers to physical activity (pa) test of sig. types of physical activity different barriers to physical activity vigorous n=49 n % mild and moderate n=451 n % body-related *p=0.0370.0%06.9%31shyness from others when doing exercise **p=0.0244.1%214.6%66shyness from body looks in front of people convenience *p=0.3761.2%3064.7%292lack of time **p=0.438.2%46.7%30inconvenient weather resource *p=0.07220.4%1031.5%142lack of convenient place *p=0.2110.2%515.7%71lack of interest in pa *p=0.0216.3%831.0%140lack of facilities **p=0.0688.2%417.3%78lack of knowledge social *p=0.2310.2%56.4%29lack of participation from friends **p=0.522.0%13.3%15lack of skilled friends **p=0. 72.0%12.2%10bad behaviour of friends fitness **p=0.320.0%02.4%11too overweight to do pa **p=0.1410.2%517.3%78pa is uncomfortable or difficult *chi-square (χ2). **fisher’s exact test. sajsm vol 23 no. 4 2011 115 by lemos et al., 23 who used the ipaq as he found that 8.4% of the university students in spain were vigorously active. higher rates of activity reported in other studies that assessed vigorous activity as the activity that ‘made you sweat or breathe hard’ engaged in for 20 minutes or more (e.g. staten et al. 24 ) reported that 39% of university students in one of usa public universities were vigorously physically active. porter et al., 25 found that 44.3% of south african university students reported having engaged in vigorous physical activity on 5 or more of the 7 days preceding the survey. the variation of these prevalences among different countries is a reflection of the different socio-economic status, availability of facilities and also the different tools used for the assessment. females reported less vigorous activity than males, which is similar to the results described by others. 26,27 this may be due to lack of time associated with their responsibilities and care-giving duties to their mothers and family and also the body-centered issues related to their shyness and religious issues in islamic society. also in egyptian society, many women rarely practise physical activity except for weight loss. concerning residence, vigorous activity was more prevalent among urban inhabitants than rural inhabitants, and this may be due to the availability of resources such as equipped clubs, gymnasium halls and sidewalks. conversely, nearly equal rates of vigorous activity were reported among low and high social class, but much lower rates were reported among middle social class. this may be explained, in part, as higher classes have greater access to facilities for physical activity with lower barriers. lower social classes lack access to advanced technology and luxury items that promote sedentary behavior; they also lack private cars for transportation, making them more dependent on public and human-powered transport. this is in contrast with what was reported by landsbaugh, 28 who found that as socio-economic status level increased, the amount of physical activity increased and the amount of time reported participating in vigorous activities increased. the majority of both groups were sitting in front of computer less than 4 hours daily. nevertheless, the time spent in front of the computer was higher among those reporting participation only in mild and moderate activity. naomi et al. 29 reported that sedentary behaviour is a distinct category of activity and is not merely the absence of vigorous exercise. also samdal et al. 30 reported that it is possible for adolescents to obtain sufficient physical activity and to spend time watching tv. there was no significant difference in bmi between groups, which is in agreement with osman et al., 31 who found no significant relation between levels of physical activity and overweight status among obese subjects. however, inas 32 reported that increased intensity is correlated with a lower bmi. body-related barriers and lack of facilities were significantly higher among those reporting mild and moderate activities. these findings are consistent with a recent study that found that the number of recreational facilities was positively associated with physical activity in a national sample of adolescents. 33 however, a more recent review concluded there was no consistent association between activity and availability of facilities. 34 lack of time was slightly higher among those reporting mild and moderate activities, which is similar to that reported by salmon et al. 35 bowles et al. 36 suggested that perceived lack of time as a barrier could, in fact, be a reflection of a lack of self-motivation rather than a legitimate obstacle to regular participation in physical activities. also, most social and fitness barriers were slightly higher among those reporting mild and moderate activities. this is in agreement with zlot et al. 37 also ball et al. 38 reported that being overweight can also be perceived as a significant barrier to physical activity. most of the support factors for physical activity were significantly higher among those reporting vigorous activities. this is in agreement with mcneill et al. 39 also norman et al. 40 stated that family support is an important modifiable factor for reducing sedentary behaviour in children and adolescents. limitations this study had many limitations. it is cross-sectional, and as such causal inferences for both barriers and support factors cannot be made. in addition, it was based on self-report measures of physical activity. finally, we opted to evaluate only leisure-time physical activities, therefore individuals who did not meet the physical activity guidelines in this study may have been active in other domains (occupation, commuting and housework). conclusion and recommendations low levels of leisure-time vigorous physical activity were found among freshmen students in the current study. there was a positive relationship between the number of perceived barriers and physical inactivity. however, the support factors were strongly related to vigorous activity. in order to increase leisure-time physical activity, policymakers should focus their interventions on strategies designed to increase awareness of particular aspects of physical activity, which in turn may help individuals to overcome the perceived barriers to physical activity that were detected in this study. health education programmes should stress the benefits of physical activity, different ways of practising physical activity, including walking, and providing information concerning the recommended levels of physical activity. availability of modest clothing designed for physical activity, especially for women, may decrease shyness in this group of students. also, the lack of availability of facilities was a barrier for activities, which may be overcome by encouraging the students to visit the olympic village in the university. this facility has a subsidised programme of activities running throughout the year, including tennis, squash, football, swimming, boxing and others. university protable iv. distribution of the studied group physical activity according to support factors to physical activity test of sig.( χ2) physical activity different support factors to physical activity vigorous n=49 n % mild and moderate n=451 n % p=0.00653.1%2633.7%152perceived benefit for health p=0.00153.1%2630.4%137encouragement from others p=0.19220.4%1014.6%66transportation availability p=0.00051.0%2423.9%108participation by others 116 sajsm vol 23 no. 4 2011 grammes should encourage team building and sport competitions between students. programmes should also encourage students to decrease their weight, as overweight and obesity appeared to have an impact on activity. references 1. crone d, smith a, gough b. ‘i feel at one, totally alive and totally happy’: a psycho-social explanation of the physical activity and mental health relationships. health educ res 2005;20:600-611. 2. skidmore pml, yarnell jwg. the obesity epidemic: prospects for prevention. q j med 2004;97:817-825. 3. cdc (centers for disease control and prevention). youth risk 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obesity as a barrier to physical activity. aust n z j public health 2000;24:331-333. 39. mcneill lh, wyrwich kw, brownson rc, clark em, kreuter mw. individual, social environmental and physical environmental influences on physical activity among black and white adults: a structural equation analysis. ann behav med 2006;31(1):36-44. 40. norman gj, schmid ba, sallis jf, calfas kj, patrick k. psychosocial and environmental correlates of adolescent sedentary behaviors. pediatrics 2005;116(4):908-916. original research 1 sajsm vol. 29 2017 factors associated with lumbo-pelvic pain in recreational cyclists m rodseth, 1 msc (physiotherapy), a stewart, 2 phd 1 strada aron cotruș, bucharest sector 1, romania 014131 2 department of physiotherapy, school of therapeutic sciences faculty of health sciences university of the witwatersrand, johannesburg, south africa corresponding author: a stewart (aimee.stewart@wits.ac.za) the prevalence of non-traumatic cycling injuries, including lumbo-pelvic pain (lbpp), is estimated to be as high as 85%, with the influencing factors for the development of this type of pain in cyclists being: training, the physical aspects of cycling and bicycle set-up factors. [1,2,]. previously investigated factors include: (1) association between training factors and lbpp, (2) kinematics and position of the lower back on the bicycle (3) surface emg of the musculature of the hip, lumbar, thoracic areas and upper limbs. [1,2] these studies had very small sample sizes and did not test specific postural or movement dysfunctions. none of them investigated physical and bicycle set-up factors. the position of the cyclist on the bicycle is influenced by movement in two directions – forwards and backwards between the saddle and handlebars, and from side to side. [3] the seated position of the cyclist leads to an increased tendency towards a “round-back” posture, emphasised by the increased forward bent position assumed to reduce aerodynamic drag. [1] sustained end-range forward lumbar flexion during cycling could be pivotal in the development of lbpp. [2.3] cyclists with lbpp assume greater lower lumbar flexion compared to asymptomatic cyclists [2], supporting the hypothesis that lbpp is related to this position. the lower back and pelvis absorb and distribute loads from the legs, providing a stable base to control and power the bicycle. [3] integrated functioning of the muscle system is essential for optimal movement and stability of the lumbopelvic spine. [3] movement occurs through the pathway of least resistance, whereby more flexible structures compensate for less flexible ones creating stress and strain in a specific direction. [4] with repetitive loading, this direction-specific hypermobility is reinforced, resulting in tissue damage, pain and uncontrolled movement. [4] as cyclists habitually use the gluteus maximus muscle (gmax) in an elongated position [5], resulting in “stretchweakness” of the muscle, they place an increased demand on their hamstrings to compensate for changes in the lengthtension relationship. the increased demand on the hamstrings through the combined effects of a weak, elongated gmax and increased knee flexion moment created by using cleated pedals results in hypertrophy and increased passive stiffness of the hamstrings. [6] the imbalance in the passive stiffness of the hamstrings and lumbo-pelvic musculature induces increased movement in the lumbo-pelvic area and over time results in joint hypermobility, leading to microand eventual macrotrauma of the spinal structures.[6] weakness of the gluteus medius muscle (gmed) in individuals with low back pain leads to increased side-toside/lateral shift of the pelvis with a subsequent loss of pelvic control. the poor endurance of this muscle can also result in early-onset pelvic rotation [7] and, combined with frequent movement in the increased range, in joint hypermobility causing microand eventual macro-damage of lumbo-pelvic structures. the increased lateral shift of the pelvis during the weight shifting of pedalling, combined with lumbo-pelvic musculature impairment (especially the gmed) in transferring loads between the trunk and legs, can lead to lbpp. besides the position of the cyclist, the bicycle may influence the development of lbpp. therefore proper bicycle set-up is essential for injury prevention, safety, comfort, and peak performance. [8] with cycling, the asymmetrical variables of the body have to adapt to the symmetrical design of the bicycle to function as one unit as a result of the abnormal stress loads being placed on tendons and muscles. optimal fitting of the bicycle to the cyclist’s body geometry should result in less stress and strain, decreasing injury incidence [9] but few studies have investigated the association between lbpp and bicycle set-up. [3,9] cyclists have three contact points with the bicycle (saddle, handlebars and pedals) that determine the forwardbackward and side-to-side position critical for effective transmission of force to the pedals and optimal performance of the cyclist. the aim of this study was therefore to identify factors background: overuse injuries in cyclists are as high as 85%, with lower back and pelvis pain (lbpp) being common. the lower back and pelvis are pivotal to powering and controlling the bicycle and essential for optimal functioning, comfort and performance. cyclists spend long, continuous hours in sustained forward flexion, which is regarded as a main contributor to lbpp. cyclists with lbpp assume greater lumbar flexion but the reason has not yet been established. objectives: to identify intrinsic and bicycle set-up factors associated with lumbo-pelvic pain in cyclists. methods: this study was cross-sectional and descriptive. one hundred and twenty-one cyclists in gauteng, south africa, participated in this study. the factors proposed to be associated with lbpp were determined to be namely: lumbar curvature on the bicycle in all three handlebar positions, strength of the gluteus maximus (gmax) and medius (gmed), extensibility of the hamstrings, control of lumbar movement in the direction of flexion, neurodynamics, active straight leg raise, one leg stance test for lateral pelvic shift, leg length discrepancy and bicycle set-up (saddle height, set-back and angle, handlebar height, forward reach, cleat position). results: only the lumbar curvature in the brake lever position (p=0.03) and weakness of the gmed (p=0.05) were related to lbpp in cyclists. conclusion: this study was the first to assess the relationship between the multiple factors described above and lbpp in cyclists. understanding the relationship between increased lumber flexion in the brake lever position and the weakness of the gmed and lbpp may lead to the development of strategies to reduce lbpp occurrence. keywords: bicycle set-up, load transfer, low back, motor control, physical pain s afr j sports med 2017;29:1-8. doi: 10.17159/2078-516x/2017/v29i0a2406 http://dx.doi.org/10.17159/2078-516x/2017/v29i0a2406 original research sajsm vol. 29 2017 2 possibly associated with lbpp in cyclists in gauteng and establish this relationship. it was hypothesised that factors that could influence the forward-backward and side-to-side position of the cyclist on the bicycle, as illustrated in figure 1, could contribute to the development of lbpp. methods participants this cross-sectional descriptive study included cyclists who were 18-years or older; who had cycled for more than one year; who cycle more than three, but less than 12 hours/week (in the last 2 months); had participated in at least one road race longer than 90 km but fewer than 20 races per year; used a racing/road bicycle during training and racing on road; used cleats; had no injuries to the spine in the preceding two years nor specific structural pathology of the spine or spinal surgery. participants’ informed consent and institutional ethical approval was obtained (human research ethics committee university of the witwatersrand m110649). assessments assessments were undertaken by the first author of factors hypothesised to contribute to the development of lbpp, as recommended by an expert panel of physiotherapists, given the lack of literature. these included anthropometric; intrinsic physical and bicycle set-up factors. thirteen cyclists were included in a pilot study to assess the repeatability of the measurements of the physical factors and assessed twice, one week apart. all measurements were done on a treatment plinth fig. 1. factors influencing forward-and-backward and side-to-side position on the bicycle fig. 2. illustration of handlebar positions. left to right: upright seated position, brake lever position, drop position original research 3 sajsm vol. 29 2017 in a seated or horizontal position, with feet supported. body mass index (bmi) was calculated using body weight [electronic digital bathroom scale (carmen care) (kg)] divided by height [portable stadiometer (hs, scales2000) (m)]. bmi has a sensitivity of 83% and specificity of 76% in detecting body fat percentage at 25.5 kg/m2. a saunders digital inclinometer (saunders group inc., minnesota, usa) was used to measure lumbar angles/curvature in three positions: seated upright (hands on transverse bar of handlebars), brake lever (hands on brake hoods) and “drops” (hands on drops) (figure 2). participants performed a few pedalling cycles per riding position before stopping with pedals at the 3 o’clock and 9 o’clock positions, right foot forward. [11] the lumbar flexion curvature was calculated by subtracting the measurement at l5/s1 from t12/l1; with each of the three positions measured thrice and the means of the three measures calculated. the intra-class correlation coefficient (icc) and reliability coefficients for the static lumbar position and lumbo-sacral angle range from 0.91 to 0.97 for intra-rater reliability respectively and 0.63-0.75 for inter-rater reliability.[10] the inner range holding capacity of the gmax was assessed with the participant prone, with only trunk supported, in the neutral lumbar position; feet on floor, knees slightly flexed. [5] two pressure biofeedback units (pbu) (chattanooga) were placed under the left and right anterior superior iliac spine (asis) and inflated to 20 mmhg. an assessment was made of the passive range of hip extension, knee in 90° flexion, while the lumbo-pelvic area was stabilised in neutral. a rod was positioned to touch the posterior aspect of the thigh when the hip was in the horizontal (0°) position. the participant lifted one leg at a time into hip extension, knee in 90° flexion, until the posterior thigh touched the rod, maintaining contact, as well as neutral lumbo-pelvic alignment, for 15 seconds while the lifting, holding and lowering of the leg was measured with the pbu meters. normal inner range control of the gmax was taken into consideration when participants had successfully completed the movement twice. reliability studies have been done on the use of a dynamometer in determining the strength of the gmax during prone hip extension and on the reliability for assessing lumbar movement during passive hip extension (ĸ=0.72-0.76 and icc of 0.69-0.85) [4], but no reliability or validity studies have been done on the assessment of both through range control and the inner range holding capacity of the gmax in a prone position, with only trunk support. hamstring extendibility was assessed while supine, with the test leg in 90° hip flexion, thigh supported, knee comfortably flexed. the knee of the test leg was passively extended until the onset of firm resistance or a strong stretch sensation was felt. [11] the knee extension angle (kea) was measured with a digital inclinometer and repeated three times per leg. [11] hamstring length is regarded as normal if the kea for both legs is less than 20° and there is excellent reliability (intra-rater icc=0.90-0.98, inter-rater icc=0.90). [11] the participant was in the side lying position, with the lumbar spine and pelvis in neutral alignment and the underneath leg slightly flexed. a combination of tests was used to measure full range control and the ability to hold the inner range capacity of the gmed. [6,12] full passive range of motion was assessed by lifting the top leg into hip extension, external rotation and abduction (ext/abd/er) stabilising the neutral lumbo-pelvic position, and noting when the hip reached the benchmark of 45° abduction (marker/rod positioned). the participant then actively lifted the top leg (ext/abd/er) to the marker, maintained controlled contact for 15 seconds before smoothly lowering the leg. an inability to maintain neutral alignment of the lower back and pelvis resulted in test failure. two smoothly controlled repetitions without substituting with the hip, lower back or pelvic movements indicated through range control of the deep posterior gmed. reliability studies have been done on concentric and eccentric strength of the gmed using a dynamometer at neutral hip alignment and on pelvic control during active hip abduction. no reliability or validity studies have been done on the assessment of both full range control and inner range holding capacity of the gmed in the side lying position.[12] control of lumbar flexion was measured with the sitting forward lean test, [13] knees and hips at 90° and the participant’s lower back in a visually estimated neutral position. the s1 vertebra and a point 10 cm above this area were marked (flexible tape measure). the participant had to keep the lower back in neutral with the two points 10 cm apart while leaning forward to 120° of hip flexion (goniometer). five practice runs were done with verbal and tactile input to maintain the neutral lumbar curvature; then five times without feedback, measuring the distance between the two marks to the nearest millimetre and calculating the mean. maintaining 10 cm between the marks, or a changed position of less than 1 cm, was an indication of adequate flexion control of lumbar flexion. [14] this test has excellent inter-rater reliability (icc of 0.96, n=40). [13] neural mobility was assessed with the slump test (reflecting the lumbar position often assumed by cyclists when riding), following a six-stage sequence. this test was considered to be positive if the participant’s symptoms were reproduced at any point of the sequence and alleviated with the release of neck flexion. this test has excellent inter-rater reliability (k=0.83; icc=0.70-0.92) and intra-rater reliability (icc=0.80-0.95; r=0.88). [4] the active straight leg raise test (aslr) in the supine position was used to assess load transfer between the trunk and legs. it was proposed to assess force closure around the pelvis by assessing the amount of effort used for a low load activity. [14] the participant raised a straight leg 20 cm off the bed successively, rating perceived effort on a six point scale (0-5). this was repeated twice and the means calculated. the scores of both sides were added, resulting in a score ranging from 010. it was considered positive if the mean was greater than one and negative if less than one. [15] there is substantial inter-rater reliability (ĸ=0.70 for left aslr and ĸ=0.71 for right) in patients with chronic nslbp. [14] lateral shift of the pelvis was measured using the single-leg stance movement control test. [5] participants stood in a normal upright position with feet one-third of their trochanteric distance apart and the umbilicus aligned with an upright pole. original research sajsm vol. 29 2017 4 they then shifted their weight onto the left leg, followed by the right leg (standing on one leg). the lateral movement of the umbilicus from the midline was measured with a spirit level ruler at completion of weight transfer. this was repeated three times to each side. the means of the weight shift to the left and right sides were calculated and considered within normal limits if the shift was less than 10 cm for each leg and the difference in the shift between legs was less than 2 cm. [4] there is excellent intra-rater reliability (ĸ=0.84 and ĸ=0.67 for left and right leg respectively) and moderate to substantial inter-rater reliability (ĸ=0.65 for left and ĸ=0.43 for right) for this test. [4] leg length discrepancy (lld) was measured in the supine position from asis to the most distal part of the lateral malleolus (lm) with a flexible tape measure. asis to lm was preferred over asis to medial malleolus (mm) as it limits the influence of the contour of the thigh, provides a more direct line of measurement, and also has excellent reliability (intrarater reliability icc=0.88-0.99, inter-rater icc=0.83). two measurements were averaged and the measured difference in the lengths was divided into three categories: discrepancies less than 6 mm, 10 mm and 20 mm respectively. bicycle set-up measures the bicycle set-up was measured with the bicycle positioned on a pre-measured bicycle stand. saddle height was measured by assessing the knee flexion angle with the pedal at bottom dead centre (bdc) and the foot parallel to the ground and aligned forward using a goniometer. this was repeated three times per leg and considered acceptable if the knee flexion was between 25-35° for both legs. [16] for saddle setback a plumb line was dropped from the posterior aspect of the patella, with the crank arm of the tested leg in the horizontal forward position (3 o’clock). intersection of the pedal axle indicated a proper setback. [8, 9] the saddle angle was measured with a digital spirit level balanced from the midline touching the front and back of the saddle and recorded as level, anteriorly or posteriorly tilted, noting the magnitude of the inclination. a level or anteriorly tilted saddle was acceptable for optimal saddle angulation. [8] handlebar height was calculated by subtracting the handlebar height (floor to the top of the stem of the handlebars) from the saddle height (floor to the top centre of the saddle). a height of 5-8 cm below the saddle indicated a proper bicycle set-up. [8] this means that there is excellent intra-rater reliability for the distance from the handlebars to the floor (icc=0.98) and the seat to the floor (icc=0.98) (n=13). [10] reach distance is defined as the distance between the saddle and the handlebars, including arm and upper body length, which has a direct impact on the position of the lumbar spine and pelvis. [9] reach distance consists of the three factors involved in reaching forward from the saddle: the distance from the back of the saddle to the transverse bar of the handlebars; full arm length (acromion to metacarpal heads) and upper body length (from flat surface of plinth to incisura jugularis of the manubrium sterni in supported sitting). these were measured three times, and the means calculated and matched with the recommended reach distances. [9] cleat position was measured by palpating and marking the first metatarsal head while the participant was standing. the midfoot cleat position of the shoe was within limits if found to be in line with the first metatarsal head. [8,9] the reliability and validity of the bicycle set-up measures, except for handlebar height, have not been reported. [10] statistical analysis from a cross-sectional study it is expected that following univariate analysis no more than 10-12 factors would be associated with low back pain when testing at the liberal 0.15 level of significance. these factors were then analysed using a logistic regression and usually 10-15 subjects need to be included for each factor. [17] therefore at least 120 volunteers were included. in a univariate analysis, participants with and without low back pain were compared using the two sample student’s t-test and mann-whitney rank sum, pearson’s chisquare test or fisher’s exact test. factors at p<0.20 were included into a multivariate analysis. from the multivariate analysis (logistic regression), odds ratios and their 95% confidence intervals (ci) were calculated for included factors. testing was at the 0.05 level of significance, using stata release 12.0 statistical software. results the intra-rater reliability was excellent for the majority of the physical tests (icc/kappa >0.70), except for the lateral sway to the right, slump (final category), the gmax (final category) and the gmed (final category) (p<0.70). excellent intra-rater reliability (icc / kappa >0.70) was obtained for the bicycle setup measures, except for the saddle height (p<0.70). of the 121 participants who volunteered to participate in the physical assessment, 80% (n=97) were males and 20% (n=24) females. the mean age per gender was 47 years (± 11) for the males and 42 years (± 8) for the females. of the 121 participants, 74% (n=90) experienced lbpp during or after cycling. seventynine percent of them (n=71) were males and 21% (n=19) were females. pain during or after cycling was mostly reported around the sacroiliac joint compared to 41% with central low back pain and 27% with unilateral low back pain. the time to the onset of lbpp during cycling was between one-two hours for 28% of cyclists. for 51% this was experienced after more than two hours of cycling mostly while in the brake lever position (62%) or seated upright (41%) position. however, on the whole, training was not affected by pain (43%) or participants trained through pain (40%). for a summary of the physical and bicycle set-up assessments, see figures 3 and 4. in the univariate analysis, only lumbar curvature was related to lbpp (p=0.01-0.02). from the univariate analysis, all factors with a significance value of less than 0.2 were included in a multivariate analysis (figure 5). in the multivariate analysis, only lumbar curvature in the brake lever position (p=0.03; ci: 1.00-1.09) and weakness of the gmed (p=0.05; ci: 0.98-11.94) were associated with lbpp (table 1). the risk for lbpp increased by 1.01 times for every degree of lumbar flexion added in the brake lever position. participants with weakness of the gmed were also 3.4 times more likely to develop lbpp original research 5 sajsm vol. 29 2017 (table 1). gender was associated with bmi (p=0.005), the gmax inner range holding capacity (p=0.006), hamstring length (p=0.001), the gmed through range control (p=0.003) and thoracolumbar and lumbosacral angles and curvatures (p=0.001-0.04) in all handlebar positions. distance cycled per week was associated with gender (p=0.012). statistically significant relationships were found between bmi and the gmed (p=0.01), thoracolumbar angle (p=0.001) and lumbar lordosis (p=0.001-0.004) in all positions. only bmi (p=0.01), inner range holding capacity of the gmax (p=0.001) and hamstring length (p=0.02) had a significant relationships with the gmed. participants with poor through range control of the gmed also had poor gmax inner range holding (n=92; 85.98%) and decreased hamstring flexibility (n=78; 72.90%). holding capacity of the gmax (p=0.01) and control of the gmed (p=0.021) were associated with the length of the hamstrings. if hamstring length was poor, insufficient inner range control of the gmax (n=74, 88.10%) and the gmed control (n=78, 92.86%) also presented. hamstring length was associated with lumbosacral angle (l5/s1) in the seated upright (p=0.03; ci: 27.18-30.19), drops (p=0.03; ci: 39.69-42.51) and brake lever positions (p=0.07; ci: 31.71-34.60). the gmax inner range holding capacity was associated with lumbo-pelvic stability active straight leg raise (p=0.67) (n= 78, 64.5%) normal aslr lbpp group: (n=59, 65.6%) normal aslr lateral sway (p=0.19) normal lateral sway (n=74, 61.2%) mean sway left (sd): 7.86 (1.94) cm mean sway right (sd): 7.21 (1.92) cm -lbpp group: normal lateral sway (n=52, 57.8%) sitting forward lean (p=0.68) no lumbar flexion give with sitting forward lean test (n=114, 94.2%) mean lean (sd): 0.3 (0.38) cm -lbpp group: no flexion give/normal test (n=84, 93.3%) neural mobility (p=0.23) slump -70.25% presented with normal slump test/no neurodynamic dysfunction --lbpp group: 83.33% presented with normal slump leg-length discrepancy -76.86% less than 10 mm difference in leg-length (p=0.68) -61.16% less than 6 mm difference (p=0.68) and 2.48% more than 20 mm difference (p=0.16) mean lld: 0.632 (sd: 0.060) (p=0.67) -lbpp group: 77.78% less than 10 mm 62.22% less than 6 mm and 1.11% more than 20 mm difference muscle tests hamstring length (p=0.81) presenting with shortened hamstrings – kea >20° (n=84, 69.42%) mean left kea (sd): 23.73° (11.71) (p=0.22) mean right kea (sd): 23.52° (11.11) (p=0.80) lbpp group: decreased length/kea >20° (n=63, 70%) gmax inner range holding (p=1.00) presenting with poor gmax inner range holding capacity (n=99, 81.8%) -lbpp group: poor control (n=73, 81.1%) gmed through range control (p=0.12) -poor control (n=107, 88.4%) -lbpp group: insufficient control (n=82, 91.1%) lumbar position on bicycle brake levers slump position/lx flexion (87.60%) mean curvature: 15.93° (sd:10.11) (p=0.01) lbpp group: 88.89% in lx flexion seated in upright position -86.78% in lx flexion mean curvature: 15.23° (sd: 10.31) (p=0.01) -lbpp group: 87.78% in lx flexion drop position -92.56% in lx flexion mean curvature: 17.94° (sd: 9.65) (p=0.02) -lbpp group: 91.11% in lx flexion physical characteristics of cyclists in gauteng bmi (p=0.20) an almost equal number of participants presented with normal bmi (n=55, 45.5%) or were overweight (n=51, 42.2%) mean bmi (sd): 25.98 (3.77) kg/m² (p=0.24) -lbpp group: (n=44, 89%) normal bmi, (n=46, 51.11%) overweight/obese mean bmi (sd): 25.8 (3.8) kg/m² fig. 3. summary of the physical characteristics of cyclists original research sajsm vol. 29 2017 6 lateral sway (p=0.031), gmed control (p=0.001) and hamstring length (p=0.007). saddle angle was associated with thoracolumbar angle (t12/l1) in the handlebar drops position (p=0.02; ci: 57.7560.30). lumbar curvature in the handlebar drops position was associated with the sitting forward lean test (p=0.04; ci: 16.2019.68), while the lumbosacral angle and curvature were consistently related to sitting forward lean test. discussion flexion of the lumbar spine in the brake lever position and weakness of the gmed were associated with lbpp, with most cyclists experiencing pain in the brake lever position. this was also the most frequently adopted position in training (48% of time was spent in this position in cyclists with and without lbpp). cyclists assume a position of lumbar flexion on the bicycle, regardless of the level of competition, and those with lbpp adopt greater lumbar flexion, [1,2] as was also seen here. the mechanism by which increased lumbar flexion leads to lbpp is, however, not clear. [2,] the authors assessed several factors that could influence this position (including an inability to prevent/control lumbar flexion), but none were associated with lbpp. none of the factors, besides gender (p=0.03) and bmi (p=0.002), were related to the lumbar curvature in the brake lever position. other studies suggest the flexion relaxation phenomenon or mechanical creep but with inconclusive outcomes.[2,10] poor position sense (proprioception) with subsequent spinal repositioning error could also contribute to the increased lumbar flexion. lack of through range control of the gmed was associated with lbpp. most of the participants (88%) were unable to concentrically shorten their gmed to inner range, isometrically hold inner range, and eccentrically control the return, keeping a neutral alignment of the lumbar spine and pelvis. in this study, 91% of those with lbpp were unable to do so. neumann [18] reported an increase in hip internal rotation at greater ranges of knee flexion. cyclists are positioned in hip flexion and use increasing ranges of flexion and internal rotation during table 1. logistical regression of factors from the univariate analysis risk factor odds ratio 95% confidence interval p-value handlebar height 0.90 0.78-1.03 0.11 saddle height 0.55 0.21-1.48 0.24 lumbar curvature in brake lever position 1.01 1.00-1.09 0.03* gmed 3.43 0.98-11.94 0.05* lld <20 mm 0.21 0.02-2.61 0.22 gmed, gluteus medius; lld, leg length discrepancy * indicates all factors with a statistically significant relationship (<0.05) position of the saddle saddle height (p=0.19) cyclists’ saddle height out of the recommended range (n=78, 65%) saddle too high (n=13, 11%) saddle too low (n=26 22%) asymmetry between left and right sides in 34% (n=41) lbpp group: saddle height out of range (n=55, 61%), presenting with asymmetry between sides (n=26, 29%) or too low saddle (n=20, 22%) saddle set-back (p=0.25) presenting with a saddle set-back out of the recommended range (n=73, 60%) of which the saddle was set too far forward lbpp group saddle set-back not in recommended range (n=57, 63%). saddle angle (p=0.21) saddles tilted anteriorly (n=58, 48%) followed by (n=47, 39%) tilted posteriorly (p=0.51) mean (sd) tilt: 0.72° (2.5) (p=0.44) lbpp group: saddles tilted anteriorly (n=45, 50%) followed by (n=32, 36%) tilted posteriorly mean (sd) tilt: 0.81° (2.6) (p=0.44) cleat position (p=0.55) cyclists – cleats positioned incorrectly on shoes (n=68, 56%) lbpp group: cleats positioned incorrectly on shoes (n=52, 58%) reach (p=0.29) cyclists with an incorrect reach distance (n=110, 91 %) cyclists bunched up (reach forward too short) (n=52.9, 53%). lbpp group: bunched up (n=49, 54%) reach ratio: p=0.52 description of bicycle set-up factors handlebar height (p=0.49) cyclists with the handlebar height out of the recommended limit of 5-8 cm below the saddle (n=84, 69%) handlebars too high (n=66, 55%) -lbpp group: out of the recommended range (n=64, 71%), with handlebars again set too high (n=53, 59%) fig. 4. summary of the bicycle set-up factors original research 7 sajsm vol. 29 2017 pedalling. [21] habitual use of increased hip internal rotation and hip adduction will lead to weakness of the gmed, resulting in more hip adduction and lateral shift which could induce an increase in lumbo-pelvic rotation. this could in turn lead to microand macro-trauma of the lumbo-pelvic structures. [6] the gmed is responsible for 70% of the mediolateral stability of the pelvis; weakness thereof could result in poor lateral control, presenting as an increase in lateral pelvic shift as mechanical loads are transferred from the legs through the pelvis with pedalling. [19] lateral pelvic tilt (side-to-side rocking) occurs naturally during cycling, while exaggerated at high speeds and increased fatigue. [3] with poor lateral control, side-to-side translation is exaggerated inducing a side flexion and/or rotation moment through the lower back and pelvis [1] resulting in increased mobility and microdamage of lumbosacral structures. [6] sustained flexion with rotation is implicated in the injury of passive spinal structures, such as intervertebral discs, with resultant micro-damage to the annulus fibrosis. an unexpected finding was that there was no relationship between the one leg stance test and gmed strength (p=0.24), considering its primary role of stabilising the pelvis during the one leg stance. [19] this might be as a result of the gmed primarily control pelvic tilt as opposed to pelvic shift when other muscles such as the gmax are activated. [14] weakness in the gmed was related to gmax weakness (p=0.001) and decreased the extensibility of the hamstrings (p=0.02) but neither were related to lbpp. this relationship might be explained by a global muscle system dysfunction, where weakness in the global stabilisers (gmed and gmax) increases the load on the global mobilisers (hamstrings) leading to overuse, hypertrophy and extensibility loss. the influence of the gmed in the development of lbpp needs to be interpreted with caution and the reliability for assessing control of the gmed improved. eighty-one percent of participants had an elongated gmax, (poor inner range holding). [5] most cyclists use their gmax in a lengthened position only, needing inner range contraction and increased strength when they stand up out of the saddle, resulting in greater hip extension. muscle fatigue [6], which was not investigated, may be the reason why none of the other factors were associated with lbpp. although bicycle set-up is often regarded as the cause of lbpp [8] , no bicycle factors were related to lbpp in this study. the assessment of a static set-up compared to a dynamic set-up should be considered, as the movement and position of the lumbo-pelvic spine changes substantially during cycling. conclusion the results of this study suggest that flexion of the lumbar spine in the brake lever position and weakness of the gmed are associated with lbpp. references 1. burnett af, cornelius mw, dankaerts w, et al. spinal kinematics and trunk muscle activity in cyclists: a comparison between healthy controls and non-specific chronic low back pain subjects a pilot investigation. man ther 2004; 9:211-219. doi: 10.1016/j.math.2004.06.002 2. van hoof w, volkaerts k, o'sullivan k, et al. comparing lower lumbar kinematics in cyclists with low back pain (flexion pattern) versus asymptomatic controls field study using a wireless posture monitoring system. man ther 2012; 17:312317. doi: 10.1016/j.math.2012.02.012 3. mellion mb. neck and back pain in bicycling. clin sports med 1994; 13:137-164. pmid: 8111848 4. luomajoki h, kool j, de bruin ed, et al. reliability of movement control tests in the lumbar spine. bmc musculoskelet disord. 2007;8:90.doi: 10.1186/1471-2474-90 5. richardson ca, sims k. an inner range holding contraction: an objective measure of stabilising function of an antigravity muscle. in: proceedings of the world confederation for physical therapy: 11th international congress london, uk: 1991: 829-831. 6. sahrmann s. the hip as a factor in low back pain: evidence why relative flexibility is key. j orth sports phys ther; 2012; 42:a1114. doi: 10.2519/jospt.2012.0302 7. lee sp, powers c. description of a weight-bearing method to assess hip abductor and external rotator muscle performance. j orthop sports phys ther 2013; 43:392-397. doi: 2519/jospt .2013.4412 8. silberman mr, webner d, collina s,et al. road bicycle fit. clin j sport med 2005; 15:271-276. doi: 10.1097/01.jsm.0000 171255.70156.da 9. de vey mestdagh k. personal perspective: in search of an optimum cycling posture. appl ergon 1998; 29:325-334. pmid: 9703347 10. schulz sj, gordon sj. riding position and lumbar spine angle in recreational cyclists: a pilot study. int j exerc sci 2010; 3: 174181. pmcid: pmc4738870 11. davis ds, quinn ro, whiteman ct, et al. concurrent validity of four clinical tests used to measure hamstring flexibility. j strength cond res 2008; 22:583-588. doi: factors taken to multivariate analysis (p<0.2) distance cycled per week (p=0.19) lateral sway (p=0.19, n=38, 42.2%) lld >20 mm (p=0.16, n=1, 1.1%) gmed control (p=0.12, n=82, 91.1%) lx curvature in the brake lever position (p=0.01) lx curvature in the seated upright position (p=0.01) lx curvature in the drops position (p=0.02) saddle height (p=0.19, n=55, 61.1%) handlebar height (p=0.15) factors possibly associated with lbpp in cyclists lld>20 mm removed from list as only one participant presented with it fig. 5. summary of factors taken to the multivariate analysis analysis original research sajsm vol. 29 2017 8 10.1519/jsc.0b013e31816359f2 12. comerford m, mottram sl, gibbons sgt. understanding movement and function concepts. kinetic control movement dysfunction course. london 2004. www.rehabtrainer.com. au/ courses/resources/essentials/core-stability.pdf 13. enoch f, kjaer p, elkjaer a, et al. inter-examiner reproducibility of tests for lumbar motor control. bmc musculoskel disord 2011; 12:114. doi: 10.1186/1471-2474-12114 14. roussel na, nijs j, truijen s, et al. low back pain: clinimetric properties of the trendelenburg test, active straight leg raise test, and breathing pattern during active straight leg raising. j manipulative physiol ther 2007; 30:270-278. doi: 10.1016/j.jmpt.2007.03.001 15. mens jm, huis in’t veld yh, et al. the active straight leg raise test in lumbopelvic pain during pregnancy. man ther 2012; 17:364-368. doi: 10.1016/j.math.2012.01.007 16. peveler w, bishop p, smith j, richardson m, whitehorn e. comparing methods for setting saddle height in trained cyclists. j exerc physiol online. 2005; 8:51-55. 17. nunnally jc. psychometric theory. 2nd ed.. new york: mcgraw-hill, 1978. 18. neumann da. kinesiology of the hip: a focus on muscular actions. j orthop sports phys ther 2010; 40:82-94. doi: 10.2519/jospt.2010.3025 19. grimaldi a. assessing lateral stability of the hip and pelvis. man ther 2011; 16: 26-32. doi: 10.1016/j.math.2010.08.005 52 sajsm vol 19 no. 2 2007 introduction over the last few years, off-road cycling or mountain bike (mtb) riding as it is known, has increased in popularity among amateur cyclists, with numerous races being held annually both in south africa and abroad. these races vary from single-day ‘classic’ events of 45 75 km in length to multi-stage, multi-day events ranging between 260 and 900 km in length. participants in the races range from full-time professionals who may complete a 45 km ‘classic’ in less than 2 hours and a day’s stage in 3 6 hours, to amateur cyclists who may take up to double that time to cover the same distances. the increased popularity of these endurance and ultra-endurance events has been accompanied by increased interest in fluid replacement and although many studies have been published on runners, cyclists and triathletes completing in endurance events, little is known of the fluid replacement habits of participants in mtb endurance events. we are unaware of any study that has, to date, examined the fluid replacement needs or practices of amateur mtb cyclists who take part in endurance races, whether they be single or multi-day events. the most recent joint statement released by the american college of sports medicine (acsm), american dietetic association and dieticians of canada in 2000 regarding fluid use in athletes while training or racing, recommends the intake of 150 350 ml of a 4 8% carbohydrate solution, every 15 20 minutes. 1 this translates into a range varying from 450 ml to 1 400 ml/hr. the international marathon medical directors association (immda) has more recently published an advisory statement on fluid replacement 12 which recommends that marathon runners, however, drink ad libitum 400 800 ml/hr, with higher rates for the heavier, faster athletes in warm environmental conditions, and the lower rates for the slower runners/walkers completing original research article fluid use in mountain bikers – self-reported practices abstract background and objectives. little is known of the fluid replacement habits of participants in mountain bike (mtb) endurance events. this survey set out to determine the current perceptions and practices of this group of endurance athletes. method. four hundred and twelve participants in the 3day 2006 sani2c (mtb) race completed questionnaires that elicited information regarding their regular fluid intake practices during competitive mtb endurance events. this included their general approach to fluid replacement, their fluid intake practices (type, amount and frequency), urine output and hydration status. results. while 70% (n = 290) reported that they based their fluid intake practices on personal past experiences, less than half the group (n = 177, 43%) were aware of official sport-specific guidelines. although 86% (n = 354) reported making use of commercially available sport-specific drinks, consumption of water alone was reported by 34% of respondents (n = 140). the majority (n = 225, 55%) of the mountain bikers reported drinking every 16 30 minutes during an endurance ride, while 35% (n = 144) reported drinking every 0 15 minutes. fifty-three per cent (n = 182) of the male respondents and 45% (n = 23) of female respondents reported a routine intake of ≥ 750 ml per hour during endurance rides. this included 2 women who reported regular intakes of between 1 500 and 2 000 ml/hr. only 7 (2%) reported receiving medical care for dehydration following their participation in previous mtb rides. correspondence: e m peters discipline of physiology school of medical sciences university of kwazulu-natal private bag 7 congella 4013 tel: 031-260 4237 fax: 031-260 4455 email: futree@ukzn.ac.za s c rose (mb bch, mmed sc (sports med)) 1 j a chipps (m public health) 2 e m peters (msc (med), phd) 1 1 discipline of physiology, school of medical sciences, university of kwa-zulu-natal, durban 2 buyel’empilweni rehabilitation research group, school of nursing, university of kwazulu-natal, durban conclusions. this survey indicates that although more than half of the mountain bikers did not acknowledge specific awareness of the official fluid replacement guidelines, over 80% reported drinking regularly during a race, and 52% (n = 212) reported a usual intake of ≥ 750 ml/hr during endurance races. until scientific studies have carefully examined the hydration status and fluid replacement needs of mountain bikers, mtb cyclists are cautioned against the practice of over-hydrating. pg52-58.indd 52 7/5/07 10:34:44 am sajsm vol 19 no. 2 2007 53 marathon races in cooler environmental conditions. while the immda recommendation is supported by recent evidence of hyponatraemia induced by over-hydration during exercise, 10,14,17-20 what now needs to be established is where, within these ranges, the recommendations for mountain bikers participating in off-road endurance events should lie. it has been well established that the larger amount of mechanical work done on more robust mtbs and the greater frictional resistance on country roads, results in greater metabolic energy expenditure and heat production when travelling at equivalent speeds in given environmental conditions, than track/ road cycling. 3,4,6 in addition, mtb cyclists usually carry hydration backpacks which do not promote evaporative cooling, as opposed to road cyclists who only carry drinks bottles on their bikes and runners who do not wear the heavier lycra and nylon attire of the cyclist. as the greater mean wind-chill effect resulting from the increased air movement over body surfaces and higher convective heat losses during cycling may, however, also counter the greater relative heat gain during cycling than running, the fluid replacement needs of mtb cyclists at given cycling speeds in given environmental conditions, require scientific investigation. furthermore, multi-day mtb events, such as the cape epic or sani2c are rapidly gaining popularity in south africa and present an additional challenge to these athletes. not only does much of the literature encourage cyclists to focus on not losing more than 2% body mass during each individual stage, 17 but it has been suggested that the 16 20hour rest intervals between ‘stages’ provide an opportunity to rehydrate fully prior to each of the next stages, in an attempt to maintain fluid status and avoid the cumulative fluid loss and dehydration that may occur over a series of consecutive distance events. 5 sound hydration practices of mtb riders participating in endurance events, many of which are multi-day events, are therefore imperative and research needs to be conducted on participants in the sport discipline. the primary purpose of this initial study, the first of its nature on mtb riders, was to survey the regular fluid intake patterns/drinking habits of amateur mtb cyclists. this is followed by a review of the reported regular practices of these mtb riders in relation to the current fluid intake guidelines for other endurance sports including road running and cycling 1,9,12,13 and a discussion of the variables that will influence fluid replacement needs of these athletes. table i. description of mtb riders (n = 412) men (n = 345) women (n = 51) n/s (n = 16) total (n = 412) age (mean ± sd (years)) 39.0 ± 7.6 35.6 ± 7.2 42.2 ± 10.1* 38.7 ± 7.6 hours of riding per week (n (%)) < 5 44 (13) 5 (10) 4 (25) 53 (13) 6 10 188 (55) 27 (53) 6 (38) 221 (54) 11 15 95 (28) 15 (30) 5 (31) 115 (28) 16 20 14 (4) 4 (8) 1 (6) 19 (5) > 21 0 0 4 (1) riding ability (n (%)) ‘week-end warriors’ 44 (13) 6 (12) 2 (13) † 52 (13) serious amateurs 254 (74) 35 (70) 11 (69) † 300 (73) elite‡ 40 (11) 9 (18) 1 (7) † 50 (12) professional 1 (0) 1 (2) 0 (0) † 2 (1) other 4 (1) 0 1 (7) † 5 (1) racing experience in last year (n (%))§ none 6 (2) 0 0 6 (2) fun rider 18 (5) 3 (6) 2 (13) 23 (6) ≤ 5 ‘classics’ 133 (39) 32 (63) 9 (56) 16 (4) ≤ 6 ‘classics’ 98 (28) 18 (35) 2 (13) 118 (28) previous multistage races 125 (36) 19 (37) 4 (25) 148 (36) other 22 (6) 3 (6) 1 (6) 26 (6) *n = 6. † n = 15. ‡ regularly attain a top-10 finish in mbt races § several cyclists identified more than one factor in their response. classic = 45 75 km race; n/s = gender not specified. pg52-58.indd 53 7/5/07 10:34:44 am 54 sajsm vol 19 no. 2 2007 method permission to conduct this study was obtained from the bioethics committee for research on human subjects of the university of kwazulu-natal. anonymity was maintained on all questionnaires. respondents were categorised according to their gender, age and level of cycling performance, viz. recreational, serious, elite, amateur, or professional. information regarding the regular fluid use and drinking habits of amateur mtb riders was obtained using a survey. questionnaires were handed out to participants in the 2006 three-day sani2c mtb race at the race briefing on the evening prior to the start of the race. these elicited information regarding their regular fluid intake practices prior to and during endurance mountain bike rides (i.e. > 2 hours in duration), including their self-reported general approach towards fluid replacement, their actual fluid intake practices (type, amount and frequency), urine output and hydration status. in order to increase the response rate, a second batch of questionnaires was handed out on the evening of day 2. no further attempt was made to sample the riders who did not attend the abovementioned race briefings during the course of the multi-day event. definitions of dehydration and overhydration were not provided in the questionnaires. this allowed the cyclists to respond using their own diagnostic criteria in an attempt to include all cyclists who felt they had a problem due to inappropriate fluid intake. this also permitted researchers to record the perceptions that currently exist among mbt cyclists regarding fluid use. statistics quantitative variables are expressed as mean ± standard deviation (sd), while categorical data are presented in frequencies and percentages. binomial / nominal data were compared and tested for association using a chi-square (χ2) test. level of significance was set at p < 0.05. the database and statistics software used was epi info, version 3.32, february 2006 (centers for disease control and prevention (cdc), atlanta, usa). results sample description a total of 412 questionnaires were completed, resulting in a sample comprising 41% of the total population of athletes registered for the race (n = 996). sixty-nine questionnaires (17%) were completed after the second stage of the race. there were no statistically significant differences between the participants who completed the questionnaire before the race and on day 2 in terms of age and most key variables, except for the recall of amount of fluid taken during races. the results of the two groups are therefore reported together except in terms of hourly volumes of fluid consumed. a description and categorisation of the respondents is presented in table i. overall, 51 (12%) were female, 345 (84%) were male and 16 (4%) did not specify their gender. fifty per cent of respondents were between 30 and 39 years of age, with an average age of 38.6 ± 7.6 (range 16 71 years). seventy-three per cent (n = 300) classified themselves as ‘serious amateurs’ who participated in more than 5 races a year, while 50 (12%) were elite athletes attaining a regular top 10 finish. one hundred and forty-eight (36%) of the participants had previously participated in multistage events such as the cape epic or sani2c, with 118 (29%) of them reporting participating in 6 or more ‘classics’ (i.e. 45 75 km races) in the last year. approach to endurance rides in reporting their approach to endurance rides and their fluid intake (table ii), the majority (n = 290, 70%) indicated that they use their own personal experience. advice from friends (n = 111, 27%) and information from magazine articles (n = 87, 21%) were the second and third most common sources of information. while almost half of the group (n = 177, 43%) were aware of official sports guidelines, only 47 (11%) reported actually using official sport-specific guidelines to assist their approach to fluid intake during endurance rides. when asked to specify a guideline of which they were aware, 48 (12%) mentioned a guideline, with 750 ml/hour (n = 21, 5%) and 500 ml/hour (n = 17, 4%) being the most common. eighty-nine per cent of the riders (n = 368) felt that there is a need for more education concerning fluid use and cycling. specific needs include information on the physiology of hydration, how to evaluate and choose the correct sports drinks, how much to use, how to assess one’s hydration status and specific guidelines, especially for novices. fluid intake practices during endurance rides the most commonly used fluids/drinks consumed during a > 2-hour ride are listed in table iii. many cyclists gave more than 1 response. commercially available sports drinks were the most popular drinks during a > 2-hour ride, with 354 respondents (86%) reporting drinking sports drinks. one hundred and forty respondents (34%) reported consuming water, and of the 28 (7%) who reported consuming non-sports drinks, coke and fruit juices were the most popular. the reason most often reported for selecting a specific drink was that the drink was scientifically designed (n = 209, 51%). thirty-four per cent (n = 138) liked the taste, and only 28 (7%) reported that they selected the fluid based on advertising. twenty-seven per cent (n = 113) quoted other reasons, with 9% (n = 36) stating that it ‘worked’ for them based on previous experience, and 7% (n = 28) because they were following advice, primarily from friends and retail bicycle outlets. frequency and quantity of intake during a race most of the respondents reported drinking frequently, with 55% (n = 225) reporting drinking every 16 30 minutes and 35% (n = 144) drinking every 0 15 minutes. the volumes pg52-58.indd 54 7/5/07 10:34:44 am sajsm vol 19 no. 2 2007 55 that men and women (n = 385) reported consuming per hour (before the first and third stages of the 3-day sani2c race), are presented graphically in fig. 1. while a total of 188 (47%) reported an intake < 750 ml/hr, 179 (45%) reported an hourly intake of between 750 and 1 500 ml, and 33 (8%) an intake of ≥ 1 500 ml/hr. a comparison of the volume of fluid intake per hour in the cyclists who completed this section of the questionnaire before the race (n = 337) and those who completed it after the first 2 days of the race (n = 63), revealed a statistically significant difference between the 2 groups (χ2 = 10.61, p = 0.031), with 65% (n = 41) reporting less than 750 ml per hour after day 2 as opposed to 44% (n =147) of the respondents who completed the questionnaire before the start of the 2006 sani2c mtb race. at no stage did the difference in reported consumption between the men (n = 334) and the women (n = 51) reach statistical significance (χ2 = 2.19, p > 0.70). most respondents did not acknowledge a specific drinking routine before a race (n = 272, 66%). of the 135 (33.0%) who reported a routine, 49 (12%) reported starting with a sports drink and/or using only sports drink during the event, 41 (10%) reported starting with water, and 12 (3%) starting with a mixture of both. urine output one hundred and six riders (26%) stated that they never pass urine during an endurance ride. forty-three per cent of the respondents (n = 177) reported urinating only once every 5 endurance rides, with 62 (15%) urinating once in every 2 rides, and 57 (14%) urinating every ride. after rides, 122 (30%) acknowledged urinating within half an hour, and 152 (37%) within 30 minutes to an hour. twenty per cent (n = 82) reported taking between 1 and 2 hours to urinate, and 18 (4%) longer than 2 hours. table ii. approach of mountain bikers (n = 412) to fluid replacement during endurance rides (n (%)) men (n = 345) women (n = 51) n/s (n = 16) total (n = 412) sources of current approach to fluid use* advice from friends 89 (26) 14 (28) 8 (50) 111 (27) magazine articles 77 (22) 6 (12) 4 (25) 87 (21) personal experience 243 (70) 39 (77) 8 (50) 290 (70) official sport-specific guidelines 38 (11) 7 (14) 2 (13) 47 (11) other 18 (5) 3 (6) 0 20 (5) awareness of sport-specific guidelines for fluid use* yes 154 (45) 16 (31) 7 (44) 177 (43) no 191 (55) 35 (69) 9 (56) 235 (57) *several cyclists identified more than one factor in their response. n/s = gender not specified fig. 1. quantities of reported fluid consumption per hour by male and female cyclists during endurance mtb races before the first and third stages of the 2006 sani2c mtb race (n = 385*) (*12 did not provide details and 15 did not specify their gender). 0 3 0 6 0 9 0 1 2 0 1 5 0 1 8 0 2 1 0 m a le s f e m a le s t o t a l m a le s f e m a le s t o t a l m a le s f e m a le s t o t a l m a le s f e m a le s t o t a l < 7 5 0 m l/ h r 7 5 1 1 5 0 0 m l/ h r 1 5 0 1 2 0 0 0 m l/ h r > 2 0 0 0 m l/ h r v o l u m e ( m l /h r ) number of respondents b e f o r e 1 s t r a c e d a y b e f o r e 3 r d r a c e d a y n u m b e r o f re s p o n d e n ts pg52-58.indd 55 7/5/07 10:34:46 am 56 sajsm vol 19 no. 2 2007 hydration status fifty-eight per cent of respondents (n = 239) felt that when they finish an endurance race of more than 2 hours, they have had enough to drink. only 90 (22%) felt they had too little to drink, and 74 (18%) were ‘not sure’. fifty-seven per cent (n = 233), however, reported that they felt that they had been dehydrated at least once in every 5 rides, with only 120 (29%) reporting never considering themselves dehydrated after finishing an endurance ride. despite the relatively common self-made diagnosis of dehydration, most respondents (n = 237, 58%) felt that they had no serious problems as a result of not drinking enough, although 112 (27%) reported performing ‘worse’, 6 (2%) reported having abandoned previous races and 7 (2%) reported receiving medical care including an intravenous drip, in the past. other complications reported (n = 45, 11%) included mostly cramps (n = 14, 3%) and headaches (n = 16, 4%). only 64 (16%) reported a subjective perception of ever drinking too much, but 100 (24%) acknowledged being ‘unsure’. twenty-seven per cent (n = 51) of those who reported consuming less than 750 ml/hr (n = 188), described their performances as worse than expected. seventy respondents (17%) reported using a specific method to assess their hydrations status. these included the colour of their urine (n = 20), thirst (n = 8), assessment of weight changes before and after rides (n = 10) and performance (n = 4). discussion the first significant finding of this study was that despite the cold weather conditions on the first 2 days of the race which may have encouraged a more conservative estimation of regular fluid intake in the 17% of the sample (n = 69) who filled in the questionnaire after the end of the second day of the race, and inclusion of 51 women in the sample (12%), 52% (n = 212) of the mountain bikers reported a regular intake of > 750 ml/hr (i.e. 1 standard cycle bottle) in endurance races. this is higher than the average hourly fluid intake of 716 ml that has been reported in the new zealand ironman, a 1-day multi-sport event that takes competitors between 8 and 17 hours to complete, 19 but appears to be lower than that reported in cyclists competing in the tour de france who were found to consume a mean intake of 6.7 ± 2.0 l/day, while exercising 4 5 hours per day. 16 although it is difficult to compare the broad categories of intake reported in this study with the 450 1 400 ml/hr range that is recommended in the most recent joint position statement of the acsm, ada and doc, 1 they do lie close to the upper limit of the recent immda guidelines for marathon runners. 12 the fact that as many as 33 (8%) of the cyclists reported a regular intake of ≥ 1 500 ml/hr, may, however, be of concern. closer examination of the data reveals that despite these relatively high reported habitual fluid intakes in the majority of this sample of cyclists, 233 (57%) reported that they consider themselves to have been dehydrated at least once in every 5 rides, with 29 (7%) reporting being dehydrated more often. although this appears to lend support to the possibility of relatively high fluid intake needs of mtb riders, it is possible table iii. most commonly consumed fluids/drinks reported by mountain bikers (n = 412) drinks specified* n % use water 140 34 commercially available sports drinks 354* 86* cytomax 68 17 fit products (unspecified) 58 14 energade 48 12 energy dynamics 40 10 powerade 35 9 octane 27 7 staminade 22 5 carbo supreme 20 5 carbotrain 14 3 cytopower 11 3 carbomax (8), fastfuel (8), game (5), enervit (5), replenish (5), enduren (4), enduromax (3), others (13) 51 12 non-sports drinks 28 7 fruit juices 7 2 coke 15 4 other (e.g. soy milk) 6 2 * several cyclists identified more than one drink in their response. pg52-58.indd 56 7/5/07 10:34:46 am sajsm vol 19 no. 2 2007 57 that the symptoms that the cyclists attributed to dehydration may have been due to a wide range of causes. we need to acknowledge that these are self-reported data which, at this stage, need to be validated using scientific field research and only present preliminary pilot data. the lack of association between those reporting an intake < 750 ml/hr and self-reported past history of dehydration (n = 116, p = 0.30), and the equal number reporting previous experiences of dehydration while reporting a regular intake ≥ 750 ml (n = 140) also appears to point towards a possible change to a higher habitual intake that may have occurred following previous perceptions of dehydration events. of the 7 cyclists who acknowledged requiring medical care for ‘dehydration’ in the past, only 1 reported a current regular intake of < 750 ml/hr in this survey. fourteen of the cyclists, however, attributed ‘cramps’ to dehydration, while others (n = 13) appear to have regarded receiving intravenous fluid post-race and the need to ‘abandon the race’ as indications of being dehydrated. the theory that cramps and inability to continue exercising are associated with dehydration, has been widely disputed. 9 furthermore, there are numerous reports in the literature of inappropriate administration of intravenous fluids following endurance events. 10 as many of these selfreported perceptions of the cyclists therefore appear not to be in keeping with the present state of knowledge, 9,10,13,21 this once again supports the need for scientific validation of the status quo and further education of the riders. while more than half (52%, n = 212) of the respondents reported a usual intake of ≥ 750 ml/hr when participating in endurance rides, the effect of additional variables including environmental conditions, body mass, exercise intensity, training status and degree of heat acclimatisation on fluid intake requirements should not be underestimated. the importance of environmental conditions on attitude to fluid intake is clearly shown when one compares the responses between those who filled in the questionnaire before and after 2 unexpectedly cold days of racing. it is interesting that almost twice as many subjects who reported their regular hourly fluid intakes after the cold (ambient temperature range 9 22°c), wet and windy weather conditions on the first 2 days of the 2006 sani2c (n = 41) recorded intakes of < 750 ml/hr, compared with the number of cyclists who recorded intakes of ≥ 750 ml/hr (n = 22). body mass is known to be positively correlated with sweat rate and hence fluid intake requirements during exercise. 11 in contrast to ultradistance runners and competitive road cyclists, it is not uncommon for heavier and older athletes with a more dominant mesomorphic-endomorphic somatotyping to be attracted to mtb racing. this was confirmed by our research group in a subsample of 25 randomly selected male participants in the 2006 sani2c mtb race who presented with a range of 67 103 kg and mean of 82.5 ± 9.3 kg body mass (sc rose and em peters unpublished data). these findings may well support the higher fluid intake needs of a considerable proportion of these athletes. female ultradistance athletes have been shown to have lower fluid requirements and to be at significantly greater risk of developing hyponatraemia due to fluid overload in ultradistance triathlons than average men. 19,20 this has been attributed to their lower sweat rates as they are usually smaller, lighter and have smaller fluid compartments, and the longer time taken by women to complete events. 16 this is supported by the fact that the only reported case of exercise-induced hyponatraemia in a cyclist, has been in a female cyclist taking part in a 1-day cycling event, despite this cyclist having a modest fluid intake throughout the race. 2 although the data from this study also confirm a lower reported intake in female cyclists, with 55% (n = 28) reporting an intake of < 750 ml/hr, and the results also confirm a positive association between those women who reported drinking too much/overhydration and those who reported intake of ≥ 750 ml/hr (χ2 = 9.6805, p = 0.046), the fact that 2 women reported regular hourly intakes of 1 501 2 000 ml (fig. 1), is of concern. it is also well accepted that racing speed, which determines metabolic rate and sweat rate, is one of the primary determinants of fluid replacement needs. 11 interestingly, mtb cyclists who fell into the ‘elite’ and professional categories in this study (table i), did not report higher regular fluid intakes than the serious amateurs and recreational cyclists. this would also confirm previous findings 14,22 and may be in keeping with a previous observation that elite runners have been recorded as having fluid intakes as low as 100 ml/hr. 14 while heat acclimatisation has been shown to result in enhanced sweat rates ranging between 800 ml/hr and 900 ml/hr and greater water content of the sweat, 7 endurance training is also well known to increase both blood volume and sweat rate at a given exercise intensity. 11 we were, however, not able to identify positive association between the volume of fluid taken in by our cyclists and the level of training or performance of these athletes. although the findings of this preliminary survey appear to support an average regular intake of ≥ 750 ml/hr during mtb races, determination of the optimal fluid intake for recreational endurance athletes such as mtb riders, is complex and will vary depending on environmental circumstances, gender, training/performance status and anthropometrical characteristics of the cyclists. as only 43% of the mtb riders surveyed in this study reported an awareness of official sports guidelines regarding fluid replacement, the education of mtb cyclists regarding the factors that influence their fluid replacement needs, is imperative. the riders need to be made aware of the dynamic nature of endurance events and the need to be able to adapt the guidelines to their particular individual needs and the impact of environmental conditions on these needs. providing guidelines for fluid use by mtb cyclists, in particular participants in multistage events is, therefore, no simple matter. appropriate fluid intake may vary from day to day and a uniform approach may lead to both over and under-hydration depending on the numerous dynamic factors mentioned above. although there are no case pg52-58.indd 57 7/5/07 10:34:46 am 58 sajsm vol 19 no. 2 2007 reports or clinical trials that unambiguously link exerciseinduced dehydration with life-threatening, exercise-induced disorders, 21 the ingestion of excessive amounts of water before and during endurance races can cause a reduction in blood sodium concentrations and cerebral oedema, as the osmotic balance across the blood-brain barrier is disrupted. hyponatraemic encephalopathy, which has been reported in runners, triathletes, army personnel and recreational hikers following fluid overload, can be potentially fatal. 8,10 the findings of this survey therefore underline the urgent need for scientific field research to be conducted in order to improve the fluid intake practices of this group of endurance athletes. directions for future research should include assessments of the metabolic and fluid needs of mtb racers in different environmental circumstances, at different intensities of effort by cyclists of different fitness levels, degrees of heat acclimatisation and somatotyping. as the hazards of overhydration and exercise-induced hyponatraemia are well described, 9,10,15,20,21 it is imperative that the findings of this first preliminary survey which appear to point towards an intake in the upper range of official guidelines, are validated in carefully conducted scientific field studies that examine the fluid status and haematological profile of these athletes under varying conditions. references 1. american college of sports medicine, american dietetic association and dieticians of canada. joint position statement: nutrition and athletic performance. med sci sports exerc 2000; 32: 2130-45. 2. dugas jp, noakes td hyponatraemic encephalopathy despite a modest rate of fluid intake during a 109 km cycle race. br j sports med 2005; 39: e38. 3. impellizzeri fm, marcora sm, rampinini e, mognoni p, sassi a. correlations between physiological variables and performance in high level cross country off road cyclists. br j sports med 2005; 39: 747-51. 4. impellizzeri f, sassi a, rodriguez-alonso m, mognoni p, marcora s. exercise intensity during off-road cycling competitions. med sci sports exerc 2002; 34:1808-13. 5. kovacs em, schmahl rm, senden jm, brouns f. effect of high and low rates of fluid intake on post-exercise rehydration. int j sport nutr exerc metab 2002; 12:14-23. 6. lee h, martin dt, anson jm, grundy d, hahn ag. physiological characteristics of successful mountain bikers and professional road cyclists. j sports sci 2002; 20: 1001-8. 7. maughan r, shirreffs s. exercise in the heat: challenges and opportunities. j sports sci 2004; 22: 917-27. 8. montain sj, cheuvront sn, sawka mn. exercise induced hyponatraemia: quantitative analysis to understand the aetiology. br j sports med 2006; 40: 98-106. 9. noakes td. exercise in the heat. old ideas, new dogmas. int sports med j 2006: 7: 58-74. 10. noakes td, sharwood k, speedy d, et al. three independent biological mechanisms cause exercise-induced hyponatraemia: evidence from 2 135 weighed competitive athletic performances. proc natl acad sci usa 2005; 102: 18550-5. 11. noakes td, myburg kh, du plessis j, et al. metabolic rate, not percent dehydration, predict rectal temperature in marathon runners. med sci sports exerc 1990; 23: 443-9. 12. noakes td. immda advisory statement on guidelines for fluid replacement during marathon running. new studies in athletics. iaaf technical quarterly 2002; 17: 15-24. 13. peters em. nutritional aspects in ultraendurance exercise. current opinion in nutrition and metabolic care 2003; 6: 427-34. 14. pugh lg, corbett jl, johnson rh. rectal temperatures, weight losses, and sweat rates in marathon running. j appl physiol 1967; 23: 347-52. 15. rehrer n. fluid and electrolyte balance in ultra-endurance sport. sports med 2001; 31:701-15. 16. saris wh, van erp-baart ma, brouns f, westerterp kr, ten hoor f. study on food intake and energy expenditure during extreme sustained exercise: the tour de france. int j sports med 1989; 10: s26-s31. 17. sawka mn. physiological consequences of hypohydration: exercise performance and thermoregulation. med sci sports exerc 1992; 24: 657-70. 18. sharwood k, collins m, goedecke j, wilson g, noakes td. weight changes, sodium levels, and performance in the south african ironman triathlon. clin j sports med 2002; 12: 391-9. 19. speedy db, noakes td, kimber ne, et al. fluid balance during and after an ironman triathlon. clin j sports med 2001; 11:44-50. 20. speedy db, noakes td, rodgers ir, et al. hyponatraemia in ultradistance triathletes. med sci sports exerc 1999; 31: 809-15. 21. speedy db, noakes td, schneider c. exercise-associated hyponataemia: a review. emerg med 2001; 13:17-27. 22. wydenham ch, strydom nb. the danger of inadequate water intake during marathon running. s afr med j 1969; 43: 893-6. pg52-58.indd 58 7/5/07 10:34:47 am sajsm editorial.indd 98 sajsm vol. 26 no. 4 2014 i write this editorial with sadness as the death of my friend richard stretch is still fresh in my mind. richard died on 27 october 2014 from complications arising from fairly routine surgery he had a week before. i met richard when we were both students in an honours programme at rhodes university. we had both worked before continuing with our studies, making us slightly older than the other students in the class. we became friends immediately and remained good friends until he died. richard played cricket at a high level, with an average of 25.9 runs in �rst division cricket. he captained the south african country districts cricket team for a number of years as a wicketkeeper-batsman. he retired from active cricket in 1982 and a�er his cricket career he served on the border cricket board, with a three-year term as president, and then on the eastern province cricket board. it was not surprising that he channelled all his scienti�c work into the game. as a former cricket player and cricket administrator he had an advantage as a scientist studying cricket because he had insight into relevant questions. he was on the south african cricket medical commission for several years and chairperson of the cricket section of the world commission of sport science. richard was also responsible for organising the world congress of science and medicine in cricket, which coincides with the cricket world cup. �ere have been four of these events since its inception and he has been involved in every one. as his academic career developed, he published papers on various aspects of cricket and developed a reputation as one of the top international cricket researchers. in 2005 he was invited to co-author a paper on guidelines for definitions for injur y surveillance studies in cricket.[1] this paper has defined the area and ser ves as the doctrine for researchers involved in cricket injury studies. any researcher who does not use these definitions and tries to get their work published in mainstream journals will probably fail. richard published 21 papers on various aspects of cricket in isi-credited journals. these papers have been cited 262 times and were the reason why he became an nrf-rated scientist about 10 years ago. even though we lived and worked in cities about 800 km apart we had contact several times a year. meeting him was always refreshing. he would start by updating me on his family news and ask with interest about mine. it gave me great pleasure to hear his stories about his three children, who made him so proud and who have grown up into exceptional young adults, and his wife sandra who he clearly loved dearly. richard will be remembered as someone who had a rich family life and who made a signi�cant contribution internationally with his research on various aspects of cricket. he was able to maintain a balance between his family life and work; a balance that many people strive for, but which only a few attain. it gives me pleasure to know that his last paper will be published in this edition of the journal. �e paper, ‘junior cricketers are not a smaller version of adult cricketers: a �ve-year investigation of injuries in elite junior cricketers’, was accepted for publication about four weeks before he died. i know this paper meant much to him as it pulled together the knowledge he had gained from many of his earlier studies. richard will be missed, but his contribution to the science of cricket, both locally and internationally, will remain forever. 1. orchard j, newman d, stretch r, frost w, mansingh a, leipus a. methods for injury surveillance in international cricket. j sci med sport 2005;8(1):1–14. mike lambert editor-in-chief s afr j sm 2014;26(4):98 doi:10.7196/sajsm.98 editorial richard stretch – a cricket icon (1952 2014) 692 of boksmart’s mandate is to record serious and catastrophic head, neck and spine rugby injuries in south africa (sa), and to formulate appropriate initiatives aimed at prevention of these injuries.4 even though spinal cord injuries in rugby union are few, there are inherent risks associated primarily with the tackle and scrum6 that are the main contributors to spinal injuries, with scrum injuries consistently being more severe.3–5 7 10 over the last 4 years in sa, these phases contributed to 78% of all serious and catastrophic head, neck and spine injuries in rugby, with the tackle and scrum contributing to 41% and 37% respectively; 55% and 74% of these injuries being permanent in nature, that is, with neurological deficit, quadriplegia or death. considering that tackle events are more common in a match, the relative risk of catastrophic outcome in scrums is therefore considerably higher. intervention – what can be done about neck injuries? targeted interventions on scrum-related spinal cord injuries are effective.4 7 10 the french rugby union instituted new laws for scrumming, for non-professional players, and a new medical licensing procedure for front-row players called the ‘rugby passport’.7 new zealand’s rugbysmart programme had similar results using a different strategy.7 10 it is possible that the scrum may be more amenable to education-based injury-prevention initiatives than the unstructured tackle, ruck and maul.10 rugbysmart provides evidence that educational programmes are indeed a viable option for decreasing serious spinal injuries in scrums.10 12 for this reason, boksmart implemented an educational approach akin to that of rugbysmart, but incorporated additional elements outlined in the 4-part programme to accommodate the south african rugby landscape. concussion and fatal head injury another key component to address proactively is concussion, the consequences of boksmart – implementing a national rugby safety programme w viljoen,1 j patricios2 the boksmart national rugby safety programme is a joint initiative between the south african rugby union and the chris burger/petro jackson players fund aimed at implementing evidence-based sports medicine and exercise research to prevent injury and enhance performance at all levels of rugby union in south africa. the boksmart programme has four main elements: the boksmart rugby safety workf shops, a compulsory dvd-facilitated course that all coaches and referees in sa attend on a biennial basis, the boksmart rugby medic f programme, an entry-level rugby first aid short course aimed at training members of underprivileged rugbyplaying communities, the toll-free boksmart spineline numf ber, which assists in the management and road transport of head-, neckand spine-injured rugby players to the nearest appropriate medical facility, and the freely accessible online educaf tional resource www.boksmart.com, which provides researched documentation and practical advice on a variety of rugby-related topics. injury surveillance – a key element head and neck trauma form a large part of the injuries associated with contact and collision sport.6 rugby union is a collision sport that exposes players to cervical spinal injuries, with permanent disabling injuries being the most serious and highly publicised complication.7 part which have seen a number of concussionrelated fatalities in south african rugby. the boksmart philosophy is that the outcome of a properly managed concussion should never be catastrophic in nature, and proper education on preventing, identifying, managing, treating and rehabilitating a player before returning to match play forms an integral part of the programme. boksmart’s education programme reflects the most recent international consensus statement on concussion in sport.13 14 a toll-free hotline manned by emergency medical service personnel who have received additional boksmart training, enables coaches and referees to access appropriate emergency medical advice and treatment. the programme also developed a simple preparticipation screening tool for coaches,15 which recognises concussion and neck injury history as an important predictor of catastrophic injury.6 13 each coach and referee also receives a pocket concussion guide, which assists in providing appropriate guidance for managing potentially concussed players on field. turning research into practice – efficacy to effectiveness a major challenge is turning injury prevention research into behaviour change. if causative behaviour can be amended, injuries may be prevented. in practice, one needs to find a realistic solution combining both science and pragmatism to lead to positive behavioural change.8 9 even the most scientifically proven, effective interventions do not necessarily guarantee compliance, or translate into success, in preventing injuries in the real-world context.1 8 9 only proven and effective interventions that become standard practice will stand a chance of preventing these injuries.8 many interventions do not take this into account and sometimes are simply not usable in the field.8 if one explores the current literature available, there are various models to strategically align injury-prevention initiatives.1 2 8 9 in practice, your approach sometimes becomes a myriad of these, especially when the sporting landscape, as in sa, is extremely diverse with different cultures, languages, socioeconomic statuses and disparate levels of education. planning, developing and implementing an evidence-based, effective intervention in all communities is complex. boksmart has used a multifaceted approach1 6 10 incorporating as many of its rugby stakeholders as possible, and availing its content via different educational 1south african rugby union, cape town, south africa 2morningside sports medicine, johannesburg and section of sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa correspondence to dr wayne viljoen, south african rugby union, 5th floor, sport science institute building, boundary road, newlands, 7700, cape town, south africa; waynev@sarugby.co.za br j sports med august 2012 vol 46 no 10 editorial group.bmj.com on february 4, 2016 published by http://bjsm.bmj.com/downloaded from http://bjsm.bmj.com/ http://group.bmj.com editorial 693 references 1. finch cf, donaldson a. a sports setting matrix for understanding the implementation context for community sport. br j sports med 2010;44:973–8. 2. finch cf. getting sports injury prevention on to public health agendas addressing the shortfalls in current information sources. br j sports med 2012;46:70–4. 3. maclean jg, hutchison jd. serious neck injuries in u19 rugby union players: an audit of admissions to spinal injury units in great britain and ireland. br j sports med 2011 (in press). 4. hermanus fj, draper ce, noakes td. spinal cord injuries in south african rugby union (1980-2007). samj 2010;100:230–234. 5. dunn rn, van der spuy d. rugby and cervical spine injuries – has anything changed? a 5-year review in the western cape. samj 2010;100:235–238. 6. mcintosh as, mccrory p. preventing head and neck injury. br j sports med 2005;39:314–8. 7. bohu y, julia m, bagate c, et al. declining incidence of catastrophic cervical spine injuries in french rugby: 1996-2006. am j sports med 2009;37:319–23. 8. verhagen e, finch cf. setting our minds to implementation. br j sports med 2011;45:1015–6. 9. verhagen ea, van mechelen w. sport for all, injury prevention for all. br j sports med 2010;44:158. 10. quarrie kl, gianotti sm, hopkins wg, et al. effect of nationwide injury prevention programme on serious spinal injuries in new zealand rugby union: ecological study. bmj 2007;334:1150. 11. noakes td, draper ce. preventing spinal cord injuries in rugby union. bmj 2007;334:1122–3. 12. gianotti sm, quarrie kl, hume pa. evaluation of rugbysmart: a rugby union community injury prevention programme. j sci med sport 2009;12:371–5. 13. mccrory p, meeuwisse w, johnston k, et al. consensus statement on concussion in sport – the 3rd international conference on concussion in sport held in zurich, november 2008. j sci med sport 2009 2009;12:340–51. 14. patricios js, kohler rmn, collins rm. sportsrelated concussion relevant to the south african rugby environment – a review. sajsm 2010;22:88–94. 15. patricios js, collins rm. boksmart: preparticipation screening of rugby players by coaches based on internationally accepted medical standards. sajsm 2010;22:62–65. 16. van mechelen w, hlobil h, kemper hc. incidence, severity, aetiology and prevention of sports injuries. a review of concepts. sports med 1992;14:82–99. 17. posthumus m, viljoen w. boksmart: safe and effective techniques in rugby union. sajsm 2008;20:64–70. play a critical role in seeking maximum effect and compliance. boksmart regularly engages with relevant stakeholders, and partners with them around delivery developments.2 each course builds on the previous course, and the format of these courses progressively adapts to the educational needs of the participants. this also ensures that the educational materials remain up to date and provide current evidence-based best practice information to rugby participants.10 12 to increase commitment to the programme, the content also needs to be suitable for the audience with plain language take-home messages.12 the main requirement is now to establish whether the knowledge and skills acquired by the coaches and referees are actually being translated into their practices on field.8 an expert, international research team is currently evaluating the implementation of the boksmart programme9 in collaboration with the university of cape town’s research unit for exercise science and sport medicine. in summary – boksmart is an example of acknowledging a major problem, identifying risk factors, developing strategies to target the problem, implementing these initiatives and putting independent processes in place to evaluate the success of the programme. the elements of the programme demonstrate the practical implementation of an injury prevention and rugby safety programme using an evidence-based approach, yet keeping in mind the rugby landscape within a south african context in an attempt to maximise adoption and impact of the programme. the ultimate result is aimed at safer rugby, and fewer catastrophic injuries. key to maximise compliance and uptake is ongoing research, keeping current with the injury patterns of the game, regular interaction and collaboration with all rugby stakeholders, constant education of all role players, and fluid and modifiable implementation strategies that are moulded to the needs of the times. competing interests none. provenance and peer review not commissioned; internally peer reviewed. received 12 april 2012 accepted 13 april 2012 doi:10.1136/bjsports-2012-091278 platforms.2 this helps ensure that the strong evidence base or interventions can be applied effectively in the ‘real world’.1 lessons – what worked? one of the key pillars of the programme is the educational courses modelled on the dvd-facilitated approach utilised in new zealand.12 rugbysmart10 12 was originally modelled on van mechelen’s16 approach and built on the foundation work of earlier initiatives.10 as with rugbysmart, the boksmart programme is focused at community level, and is implemented throughout the country.12 17 in the first 2-and-half years, boksmart has trained roughly 38 500 coaches and referees on the rugby safety course. on-going research into the primary problem is critical in ensuring effectiveness in one’s approach, and proactively addressing the identified risk factors as they surface.10 we monitor feedback from the target audience, that the desired level of interaction is being achieved, and that the product is being well received. we regularly engage with field-related experts to ensure that the intervention strategy is fluid and modifiable. this guarantees the best possible chance of learning and transfer. understanding the barriers and enablers to the extensive adoption and sustainability of your intervention, is a crucial component in focusing your implementation efforts.1 boksmart recognises that programme leaders must continually consider different implementation and intervention delivery approaches.2 one method of structuring a prevention programme is using the intervention mapping (im) protocol, which is made up of five steps, that is, (1) defining the programme objectives based on the extent of the problem, (2) selecting the most appropriate method(s) to change the targeted behaviour or outcome, (3) designing the intervention and selecting, testing and producing the materials, (4) developing the implementation plan and (5) evaluating the intervention’s effect.9 the im protocol is a continuous and consistent dialogue with all stakeholders involved to make sure that the intervention is acceptable and feasible from an implementation perspective.9 hence, the boksmart programme has stakeholder expert advisory and ground-level operational panels that br j sports med august 2012 vol 46 no 10 br j sports med 2012;46:692–693. group.bmj.com on february 4, 2016 published by http://bjsm.bmj.com/downloaded from http://bjsm.bmj.com/ http://group.bmj.com safety programme implementing a national rugby−boksmart w viljoen and j patricios doi: 10.1136/bjsports-2012-091278 2012 2012 46: 692-693 originally published online may 19,br j sports med http://bjsm.bmj.com/content/46/10/692 updated information and services can be found at: these include: references #biblhttp://bjsm.bmj.com/content/46/10/692 this article cites 15 articles, 7 of which you can access for free at: service email alerting box at the top right corner of the online article. receive free email alerts when new articles cite this article. sign up in the collections topic articles on similar topics can be found in the following collections (268)editor's choice notes http://group.bmj.com/group/rights-licensing/permissions to request permissions go to: http://journals.bmj.com/cgi/reprintform to order reprints go to: http://group.bmj.com/subscribe/ to subscribe to bmj go to: group.bmj.com on february 4, 2016 published by http://bjsm.bmj.com/downloaded from http://bjsm.bmj.com/content/46/10/692 http://bjsm.bmj.com/content/46/10/692#bibl http://bjsm.bmj.com//cgi/collection/editors_choice http://group.bmj.com/group/rights-licensing/permissions http://journals.bmj.com/cgi/reprintform http://group.bmj.com/subscribe/ http://bjsm.bmj.com/ http://group.bmj.com introduction gender verification of female athletes during international sporting events is not a recent issue. the possibility that men, who have in most cases an unfair biological advantage, could masquerade as female athletes has been a concern since women started competing in individual athletic events. the history, methods and issues related to gender verification have been reviewed on a regular basis in the scientific literature over the years.1-6 although athletes from many nations have been subject to the various verification methods used over the years, this issue has, from a south african perspective, recently been extensively debated in the public domain in an unprecedented way. caster semenya, the women’s 800 m gold medallist at the berlin world championships during august 2009, refuelled the debate on gender testing in sport. the purpose of this review is to investigate the historical and current practises and understanding of gender verification within the medical and scientific community. gender, sex and performance the term gender verification has predominately been used in the scientific literature 1-5 and by various sporting bodies, including the international olympic committee (ioc)5 and international association of athletics federations (iaaf) 7 to describe and debate the issue of testing and verifying that only eligible athletes compete in female events. gender is however a social construct comprising not only biological but also social and other non-biological differences between males and females.8 the term sex, on the other hand, refers solely to the biological difference between individuals and in the vast majority of cases can be divided into two clear categories: male and female.8 although we recognise that gender issues are important in the sporting arena, the term sex verification or testing will be used in this review to highlight the biological differences between male and invited review the science and management of sex verification in sport abstract the verification of gender eligibility in sporting competition poses a biological and management challenge for sports science and medicine, as well as for sporting authorities. it has been established that in most sporting events, the strength and power advantage possessed by males as a result of the virilising action of hormones such as testosterone produce significant advantages in performance. for this reason, males and females compete largely in separate gender categories. controversies arise as a result of intersex conditions, where the classification of individuals into male or female is complex. the present review provides the historical context to the debate, identifying the origins of gender verification as a means to deter cheating. it describes how various testing methods have been attempted, including physical examinations of genitalia, molecular techniques including genetic screening, and complex multidisciplinary approaches including endocrinological, genetic and gynaecological examination. to date, none appear to have provided a satisfactory resolution to the problem, and appear instead to have unfairly discriminated against individuals as a result of inappropriate application of testing results. sporting authorities have formulated position stands for the management of such cases, but there is not absolute agreement between them and little evidence to support whether intersex individuals should or should not be allowed to compete in female categories. correspondence: dr r tucker uct/mrc research unit for exercise science and sports medicine po box 115 newlands 7725 south africa tel: +27 21 650 4570 fax: +27 21 686 7530 e-mail: ross.tucker@mweb.co.za ross tucker (phd)1 malcolm collins (phd)2,1 1 uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town 2 south african medical research council, cape town sajsm vol 21 no. 4 2009 147 fig. 1. relative differences between male and female world records for various athletic field, track and road events. the world records for the individual male events is on average 12.6±2.3 % (ranging from 9.2% to 17.6%) faster than the female events. sc = steeple chase; m = metres; km = kilometres. fig. 1. relative differences between male and female world records for various athletic field, track and road events. the world records for the individual male events is on average 12.6±2.3 % (ranging from 9.2% to 17.6%) faster than the female events. sc = steeple chase; m = metres; km = kilometres. female athletes which generally give male athletes an unfair advantage over their female counterparts.9 with the exception of the equestrian events, where male and female athletes compete together in all olympic events (www. olympic.org), male athletes have a performance advantage over female athletes. this is illustrated by a comparison between male and female world records in track and field events, as well as the standard marathon, where men’s world records are between 9% and 18% better than women’s records for those events allowing a direct comparison to be made (fig. 1). similar performance advantages can be measured in cycling, speed-skating and swimming events (data not shown). as a result of this performance difference, women compete in a category separate to men to ensure equality of competition. in addition to sex, weight classes are also used to categorise athletes in open competition where weight differences are believed to have a biological advantage. these sports include, among others, boxing, weight lifting, and the martial arts disciplines (www.olympic.org). unlike weight, which can be accurately determined using a calibrated scale, the science of sex verification is more complex and controversial. stop men competing as women athletes, coaches, officials, the media and spectators have always been aware and concerned that there is the potential that male athletes would deliberately disguise themselves as women and compete as female athletes in individual events. this issue attracted much media attention during the 1936 berlin olympic games where herman ratjien competed in the high jump for germany as dora ratjen.3 although ‘dora’ finished only 4th in that competition, ‘she’ eventually set a world record at the european championships 2 years later (http://en.wikipedia.org/wiki/dora_ratjen). it has been alleged that ratjen was forced to disguise himself as a female athlete by the nazis.3 it is also reported that due to abnormalities with his genitalia, herman was registered as dora at birth and raised as a girl (http://en.wikipedia.org/wiki/dora_ratjen). this case, as well as other accusations of male athletes masquerading as females during the berlin games,6 as well as rumours and innuendos during the 1960 rome olympic games prompted the ioc and iaaf to establish rules to stop men cheating during competition thereby enabling female athletes to compete on an equal basis.1-4,6 sex verification – not a simple problem the berlin games also highlighted that sex verification is not a simple scientific and medical problem to solve. polish-born stella welsh (stalislawa walasiewicz), who had moved to the usa in 1932, and the american helen stephens both competed in the women’s 100 m sprint.6 walsh had won the 100 m gold medal in 1932, and was speculated by many to be male, receiving the nickname ‘stella the fella’ from the media (http://en.wikipedia.org/wiki).6 helen stephens beat walsh in the 100 m event at the 1936 games, and although there was no official gender testing during the games, stephens passed a crude examination of her external genitalia after she was accused of being a male by stella welsh.6 interestingly, stella welsh was discovered to have ambiguous genitalia and abnormal sex chromosomes during an autopsy after she was a victim of a shooting incident in 1980,6 highlighting that sex verification during sporting events would not only identify those cheating but also athletes with a rare intersex condition. an unanswered question is whether these intersex conditions might confer a sporting advantage to certain individuals who compete as females, and whether this advantage should form the basis for exclusion from female competition. as will be discussed in this review, one cannot exclude the inevitable possibility that female athletes with a rare intersex disorder could be unfairly disqualified and barred from competing in athletic events, especially if inappropriate testing is done and the issue is poorly managed. in addition, the potential for long-term psychological harm to the athlete concerned can not be under-estimated. disorder(s) of sex development intersex is a rare disorder which is usually identified at birth by the atypical appearance of the genitalia, making sex assignment difficult. the incidence has been estimated as approximately 1 in 5 000 births, but can be as high as 1.7% when conditions such as turner’s and kleinfelters’s syndrome are included.6 the classification of the intersex disorders is challenging and controversial, but these conditions were recently grouped under the collective name disorder(s) of sex development (dsd) by the international intersex consensus conference.10 dsd is not a single disorder but rather a spectrum of conditions ranging from those with ambiguous external genitalia, those with external female genitalia and varying degrees of internal testis.2,10 history of sex verification the current practices and beliefs with respect to the science and management of sex testing in sport need to be understood in its historical context. when sex verification was first introduced in international sporting competition during the early 1960s, female athletes underwent physical examinations where they stood before a committee of experts, in what became known as the ‘nude parade’.6 this resulted in widespread resentment by the athletes, prompting the ioc to seek other simpler, objective and more dignified methods of sex testing. the sex chromatin (or buccal smear) test, which requires the identification of barr bodies during microscopic examination of cells scraped from the inner lining of the athlete’s cheek, was developed and first introduced during the 1968 mexico city olympic games. human dna is packed into 22 pairs of autosomes and one pair of sex chromosomes in most cell types in our bodies. under normal circumstances, females possess two x sex chromosomes and males one y chromosome and one x chromosome. the extra female x chromosome is inactivated during development to form a barr body in the nucleus of cells. the presence of a barr body is therefore an indication that the cells being tested originate from a female, whereas the absence of a barr body indicates that the cells originated from a male. since there is a direct relationship between chromosomal and anatomical sex for the majority of people, this test would be accurate in most cases. there are however a number of genetic disorders which interfere with the normal process of sex development and lead to contradictory findings between anatomical and chromosomal sex.10 as mentioned previously, these conditions are collectively referred to as disorders of sex development (dsds).10 it is the potential identification of such an individual athlete during sex testing during athletic events that is problematic. dsds can be caused by several combinations of abnormal sex chromosomes.6,10 for example, individuals with only one x sex chromosome have a female appearance (turner’s syndrome), while individuals with two x and one y chromosome (xxy, klinefelter’s syndrome) are usually infertile men.2 the barr body test would identify these individuals as female, which would allow men with klinefelter’s syndrome to compete as females. women with turner’s syndrome would ‘test as men’ due to the absence of a second sex chromosome and therefore a barr body. it should however be noted that not all athletes with abnormal sex chromosomes 148 sajsm vol 21 no. 4 2009 would potentially have a biological advantage over their female counterparts with normal sex chromosomes, and both turner’s and klinefelter’s syndrome would be unlikely to confer a performance advantage. rather, it is disorders affecting androgen function, which are discussed subsequently, that present the problem of potential performance advantages to females. it is also possible for different cells in a individual to contain different sex chromosomes.3 this is referred to as mosaicism, where some cells may present with xx and xxy chromosomes. other possibilities include xx and xy cell combinations, or x and xy cell combinations.3 an illustration of this complexity and the implications for testing is the case of ewa klobukowska, a polish sprinter who won gold and silver in the women’s 100 m and 200 m sprints at the 1966 european athletics championships in budapest.11 she was also a member of the winning team in the 4x100 m relay event. prior to the budapest championships, she won gold and bronze medals at the 1964 tokyo olympic games for the 4x100 m relay and 100 m, respectively (http:// en.wikipedia.org/wiki/ewa_klobukowska). although she passed a gynaecological exam during the budapest championships, she was the first olympic medal-winning athlete to fail a sex chromatin gender test in 1967. although her disorder was correctly, due to confidentiality and medical ethics, never officially revealed, she was nevertheless stripped of her medals.11 it has been alleged that this was a result of an xx/xxy mosaicism, although this was never officially revealed (http://en.wikipedia.org/wiki/ewa_klobukowska).11 the implication is that barr body analysis is more likely to exclude athletes unfairly than to detect those who cheat. in addition to these conditions, there are also individuals with a female appearance who have a dsd with male sex chromosomes, the so-called xy females.1,6 these individuals have apparently normal male chromosomes, but develop to adulthood as women. the disorders responsible for this phenotype can broadly be divided into (i) disorders in androgen synthesis or action and (ii) disorders of testicular development.6 an example of the former group of disorders is complete or partial androgen insensitivity syndrome (ais).1 individuals with ais have testes (which can be internal) that produce normal amounts of testosterone. however, abnormal androgen receptors, which are partly or completely insensitive to androgens, result in the development of secondary female characteristics and musculature. various grades of ais exist, ranging from complete ais to partial ais with a very mild impact on sexual development.1 this may impact on performance, since androgens are largely responsible for virilisation, including muscle development, which may confer a performance advantage. individuals with partial ais may thus develop sexual characteristics of a female, and be identified and raised female, while possessing some level of athletic performance advantage. a further complication is somatic mosaicism of the androgen receptors, as a result of de novo mutations after the zygotic stage.12 these mutations may result in different levels of sensitivity to androgens, leading to virilisation at puberty, despite childhood development as female with respect to the genitalia.12 this may have further implications for performance. santhi soudarajan, an indian middle distance runner, was stripped of her 2006 asian games silver medal in the 800 m event after failing gender testing, allegedly as a result of this condition (http://en.wikipedia.org/wiki/ santhi_soudarajan). genetic screening increases in complexity although the iaaf stopped compulsory sex testing in 1991,3 the ioc continued to screen all female participants, but replaced the barr body test with a more complex screening process which involved pcr analysis to detect the sry gene, which is found on the male y chromosome.3 the product of this gene was thought to be essential for the differentiation of the internal foetal gonad into testis, which ultimately produces the male phenotype.6 it is now known that this test also has limitations, since other genes are also required for testis development and in addition, it has been reported that individuals with xx sex chromosomes, and therefore no sry gene, can have testes.6 further, it is also possible for the sry gene to exist on the x-chromosome as a result of translocations during meiosis.11 this test was used during the 1992 winter olympics and 1996 atlanta olympic games, where all women competitors submitted a sample which was analysed. in 1992, 2 406 tests were conducted, with 5 positive samples for the sry gene and in 1996 there were 8 positive sry gene test out of 3 387 tests.3,5 these individuals were entered as females, but possessed the sry gene and in theory, excluding a translocation event during meiosis, a y-chromosome. the incidence (approximately 1 in 400) during the 1992 and 1996 games using the sry gene test were similar to the incidence reported from 1972 to 1990, where 13 positive tests were reported out of 6 561 (approximately 1 in 500).1,2 seven of the 8 athletes in the atlanta games had ais and the eighth athlete had a condition called α-5-reductase deficiency,3,5,6 which results in the failure to convert testosterone to dihydrotestosterone, an androgen which is essential for the in utero development of external male genitalia. these individuals develop externally as females, despite having high levels of testosterone and internal testes. as is the case with ais, the elevated levels of testosterone, relative to other females, is thought to confer some performance advantage, though no studies have quantified the possible magnitude of this difference. in the 2000 olympics, all 8 athletes were cleared to compete, though the reasons for this clearance were never disclosed.5,6 there are theoretical reasons why athletes with both partial ais and α-5reductase deficiency may have performance advantages, but we are not aware of the grounds for clearing these athletes for competition. eventually the ioc stopped compulsory testing of female athletes in 1999.3,5 interestingly, it has recently been reported that since 2005, four athletes had been asked to retire from athletics by the iaaf as a result of gender testing, while three others had been permitted to continue their careers (/www.sport24.co.za/content/othersport/ 262/97ea563d0618444c808b8057e9c020a6/10-09-2009-02-32/ semenya_made_to_wait). there have, for reasons of medical confidentiality, been no further descriptions or explanations of these cases, and the grounds for the different outcomes of the testing process for these individuals. this highlights the complexity of the actions that are taken against athletes, since no data exist on how dsds may confer a performance advantage to athletes. in an excellent essay entitled ‘intersex and the olympic games’, richie et al.6 summarise the effects of gender testing as follows: ‘as our understanding of gender and sexual identify increased …, it became increasingly apparent to scientists and athletes alike that determination of sex is derived from far more than our genotype. … gender testing was initially welcomed by female athletes as a method of preventing “cheaters”. however, it has become apparent that the discrimination against those with dsd was unfair and detrimental to the sport.’ they continue to mention that: ‘gender testing in athletics has never identified an individual deliberately misrepresenting their gender. testing has, however, created controversy and embarrassment for a significant number of female athletes competing, often unknowingly, with some form of intersex disorder. indeed, there is no evidence that female athletes with dsds have displayed any sports relevant physical attributes which have not been seen in biologically normal female athletes. sajsm vol 21 no. 4 2009 149 however, numerous female athletes have been unfairly barred from competing’.6 iaaf consensus statement as a result of controversies surrounding testing and the potential for unfairly barring athletes from competing, the iaaf medical and antidoping commission published the iaaf policy on gender verification in 2006.7 in it they state that there will be no compulsory, standard or regular gender verification during iaaf-sanctioned events. however, the policy continues to state that in resolving cases that may arise due to any ‘suspicion’ or if there is a ‘challenge’, determination should not be done solely on laboratory-based sex determination. instead the athlete concerned could be asked to attend a medical evaluation by a multidisciplinary panel of experts consisting of a (i) gynaecologist, (ii) endocrinologist, (iii) psychologist, (iv) international medicine specialist, and (v) expert on gender/transgender issues. to our knowledge there are no published studies in the scientific literature that have specifically shown or suggested that any of the dsds give an unfair advantage to the individual. instead the iaaf groups the dsd conditions into two broad categories, (i) those that accord no advantage over other females and (ii) those that may accord some advantage but are nevertheless acceptable.7 the former category consists of complete or near-complete ais, gonadal dysgenesis and turner’s syndrome. the latter group consists of congenital adrenal hyperplasia, androgen-producing tumours and anovulatory androgen excess (polycystic ovary syndrome).7 in all cases, the iaaf states that if testes are present, they should be removed to avoid malignancy.7 the canadian academy of sports medicine (casm) recommendations the 1997 casm position statement on sex testing (gender verification) in sport suggests that there is no evidence that the initial justification and reasons for sex testing, which were to prevent men from masquerading as female athletes, are relevant today.9 they mention that (i) the use of communal dressing rooms and showers, (ii) the clothing worn by female athletes, (iii) current protocols used for drug testing in urine, and (iv) the athlete’s personal and sporting history, significantly reduces the likelihood of men competing as women at an international level. the casm also recommends that: ‘individuals raised as females and are psychologically and socially females from childhood should be eligible to compete in women’s competition regardless of their chromosomal, gonadal and hormonal sex’.9 furthermore, they recommend that: ‘women athletes who have developed greater than average muscle mass, whether due to extreme training programmes or to genetic abnormalities such as congenital adrenal hyperplasia, incomplete/partial ais or chromosomal mosaicism should be accepted as part of the normal range of variation, similar to individuals who have grown to extreme heights.’9 the casm agrees with the current practice of disqualifying women (and men) who have increased their muscle mass by using steroids or other banned performance-enhancing drugs.9 this position is likely to be contentious among some female athletes, since it holds that these individuals should be accepted as falling within the ‘normal range of variation’. this definition of ‘normal variation’ challenges the boundary that exists between male and female competitions which, as we have described, is not as clearcut or easily identifiable as was first thought when sex testing was introduced. theoretically, dsds which result in elevated testosterone levels may confer some performance advantage over other females, if the testosterone has a biological effect on the tissues. however, evidence has not yet been provided, primarily due to the rarity of such conditions, as well as ethical matters pertaining to confidentiality. it may prove impossible to determine conclusively whether performance advantages exist or not. whether any performance advantage that may exist falls within normal variation is also a contentious issue, because, referring to the casm position stand example, athletes do not compete in categories of height. the classification of athletes into male and female categories requires that some boundary between the classes remain in place, and the contention is around whether normal variation may in fact move an individual across this boundary, and should be disallowed. at present, there is no scientific evidence to support or refute this position. conclusion the process and management of sex verification is enormously complex and poses challenges not only to the biological description of male and female, but also to social and cultural characterisations of gender and sex. the process of verification has evolved over 70 years, having first begun as a means to deter deliberate cheating, and then evolving into a process that aims to ensure fair competition in the face of conditions that are thought to confer performance advantages. however, while a range of conditions and disorders have been identified, authorities are seemingly no closer to establishing precisely how these conditions affect performance, and many athletes appear to have been unfairly excluded from competition. recognising this, a sub-committee was formed at the 13th biennial conference of the south african sports medicine association (sasma) in durban on 21 23 october 2009 to draft a position statement on gender and sex verification for the south african context. references 1. ferguson-smith ma, ferris ea. gender verification in sport: the need for change? br j sports med 1991;25(1):17-20. 2. simpson jl, ljungqvist a, de la ca, ferguson-smith ma, et al. gender verification in competitive sports. sports med 1993;16(5):305-315. 3. dickinson bd, genel m, robinowitz cb, turner pl, woods gl. gender verification of female olympic athletes. med sci sports exerc 2002;34(10):1539-1542. 4. reeser jc. gender identity and sport: is the playing field level? br j sports med 2005;39(10):695-699. 5. genel m, ljungqvist a. essay: gender verification of female athletes. lancet 2005;366 suppl 1:s41. 6. ritchie r, reynard j, lewis t. intersex and the olympic games. j r soc med 2008;101(8):395-399. 7. iaaf policy on gender verification. iaaf medical and anti-doping commission; 2006. 8. what do we mean by “sex” and “gender”? world health organization; 2009. 9. doig p, lloyd-smith r, prior jc, sinclair d. position statement: sex testing (gender verification) in sport. canadian academy of sports medicine; 1997. 10. lee pa, houk cp, ahmed sf, hughes ia. consensus statement on management of intersex disorders. international consensus conference on intersex. pediatrics 2006;118(2):e488-e500. 11. strachan t, read ap. human molecular genetics 3. 3rd ed. garland publishers; 2004. 12. kohler b, lumbroso s, leger j, et al. androgen insensitivity syndrome: somatic mosaicism of the androgen receptor in seven families and consequences for sex assignment and genetic counseling. j clin endocrinol metab 2005;90(1):106-111. 150 sajsm vol 21 no. 4 2009 sajsm editorial.indd 2 sajsm vol. 27 no. 1 2015 editorial a paediatric neurosurgeon wrote an opinion piece for the british medical journal on the unknown risks of youth rugby.[1] he explained at the start of the article that he was entitled to an opinion, having spent time ‘picking skull fragments out of the contused frontal lobes of a teenage rugby player’. he was also writing in his capacity as a ‘rugby parent’, having watched the game at close quarters. he made a couple of key points: that ‘schools, coaches, and parents all contribute to a tribal, gladiatorial culture that encourages excessive agg ression, suppresses injury reporting, and encourages players to carry on when injured’; and that although schools require risk assessments for seemingly low-risk activities, every saturday rugby teams of children face each other with the risk of incurring serious injuries. he stated: ‘fractures, dislocations, ligamentous disruptions, and dental and maxillofacial injuries are common’. in the article, he made several points about reducing the risk of youth rugby injury, summarised here in point form: • creative match scheduling • preand early season strength and conditioning programmes • considering weight rather than age categories • having policies to reduce early return-to-play a�er concussive injuries • training for proper tackle technique from a young age • consideration for non-contested scrums • meticulous refereeing, with zero tolerance for dangerous practices • non-contact options (e.g. touch rugby) as an introduction to contact rugby. his concluding comment that ‘schools, clubs, medical facilities, and, most importantly, regulatory bodies cooperate now to quantify the risks of junior rugby’ elicited reactions from several quarters. support came from a paediatric consultant, a clinical neurophysiologist, an orthopaedic and trauma surgeon, a general practitioner and a parent, who took the time to write letters to the journal. all had various points to add, but basically supported the thrust of the editorial. researchers from the university of edinburgh and bath university also responded with letters, pointing out that, in fact, much is being done with injury surveillance, research and law changes to reduce the risk of injury. while agreeing with the sentiment of reducing the risk of injury in youth rugby, the researchers pointed out that the editorial failed to represent the positive steps that are currently in place. �is type of discussion always prompts an examination of the facts. closer to home, the boksmart national rugby safety and injury prevention programme[2] was forced to examine its fundamental principles and operating procedures. �e boksmart programme has an extensive body of information published on their website (www. boksmart.com), which addresses many of the points listed in the editorial. for example, the pros and cons of age-group v. weight-based categories are presented. �e importance of periodisation and strength and conditioning are discussed, and detailed guidelines are provided for players of various ages. extensive guidelines about return to play a�er injury are also presented. as part of the programme, referees are engaged about safety, particularly the laws governing dangerous play – all referees have to be certi�ed before they are able to referee a match. coaches have to undergo training on safety techniques (particularly for scrumming and tackling). the south african rugby union has also legislated that coaches have to be boksmart certi�ed before they are allowed to coach. boksmart has a comprehensive injury tracking programme for youth tournaments,[3,4] and an extensive database that keeps track of catastrophic injuries.[5] a series of events are triggered as soon as a player, anywhere in the country, sustains a serious injury. research to examine the mechanisms of injury,[6] the cost of injuries[7] and the e�cacy of injury prevention programmes[8] is ongoing. injuries are inevitable in any contact sport, particularly a sport such as rugby in which collisions between players running at high speed is a fundamental part of the game. it is important to be critical about how the game is managed to ensure that high-risk situations are eradicated. it is also important to have valid data about the risks of injury, so that participants and, in the case of young players – parents, can make informed choices about whether they want their children to participate. however, credit should be given where credit is due, and in most countries where rugby is a popular sport, much is being done to satisfy these points. finally, it should be acknowledged that even though the number of cata strophic injuries are decreasing in junior rugby,[8] one catastrophic injury per year is one injury too many; the effect such an injury has on the individual and the family and friends of that person is ghastly. until such time as these injuries are eradicated, there is much to do. mike lambert editor-in-chief s afr j sports med 2015;27(1):2. doi:10.7196/sajsm.616 references 1. carter m. �e unknown risks of youth rugby. bmj 2015;350:h26. [http://dx.doi. org/10.1136/bmj.h26] 2. viljoen w, patricios j. boksmart – implementing a national rugby safety programme. br j sports med 2012;46(10):692-693. [http://dx.doi.org/10.1136/ bjsports-2012-091278] 3. brown j, verhagen e, viljoen w, et al. �e incidence and severity of injuries at the 2011 south african rugby union (saru) youth week tournaments. s afr j sport med 2012;24(2):49-54. 4. burger n, lambert mi, viljoen w, brown jc, readhead c, hendricks s. tacklerelated injury rates and nature of injuries in south african youth week tournament rugby union players (under-13 to under-18): an observational cohort study. bmj open 2014;4(8):e005556. [http://dx.doi.org/10.1136/bmjopen-2014-005556] 5. brown jc, lambert mi, verhagen e, readhead c, van mechelen w, viljoen w. �e incidence of rugby-related catastrophic injuries (including cardiac events) in south africa from 2008 to 2011: a cohort study. bmj open 2013;3(2):e002475. [http:// dx.doi.org/10.1136/bmjopen-2012-002475] 6. hendricks s, lambert mi, brown jc, readhead c, viljoen w. an evidence-driven approach to scrum law modi�cations in amateur rugby played in south africa. br j sports med 2014. [http://dx.doi.org/10.1136/bjsports-2013-092877] 7. brown jc, viljoen w, lambert mi, et al. �e economic burden of time-loss injuries to youth players participating in week-long rugby union tournaments. j sci med sport 2014 (in press). [http://dx.doi.org/ 10.1016/j.jsams.2014.06.015] 8. brown jc, verhagen e, knol d, van mechelen w, lambert mi. �e e�ectiveness of the nationwide boksmart rugby injury prevention program on catastrophic injury rates. scand j med sci sports 2015 (in press). [http://dx.doi.org/10.1111/sms.12414] risks of injury in youth rugby – what are the issues? km_c227-20180517092606 original research sajsm vol. 26 no. 1 2014 9 background. although variants within genes that encode protein components of several biological systems have been associated with athletic performance, limited studies have investigated the collagen genes that encode the structural components of connective tissues. objective. to investigate the association of variants within collagen genes with endurance performance in south african (sa) ironman triathletes. methods. a total of 661 white, male participants were recruited from four sa ironman triathlon events for this genetic case-control association study. all participants were genotyped for col3a1 rs1800255 (g/a) and col12a1 rs970547 (a/g). results. no independent associations were identified between col3a1 rs1800255 and col12a1 rs970547 and overall finishing time or time to complete any of the individual components (3.8 km swim, 180 km bike or 42.2 km run) of the 226 km event. the major g+a-inferred pseudo-haplotype, constructed from col3a1 rs1800255 and col12a1 rs970547, was, however, significantly (p=0.010 and p=0.027) overrepresented in the fast run tertile (58.7%) compared with the middle (53.5%) and slow (49.5%) run tertiles, respectively. the major g+t+ainferred pseudo-haplotype, constructed from col3a1 rs1800255, col5a1 rs12722 (t/c) and col12a1 rs970547, was again significantly (p=0.022) over-represented in the fast run tertile (35.2%) compared with the slow run tertile (28.9%). conclusion. our main novel finding was that the col3a1 rs1800255 and col12a1 rs970547 variants interacted to modulate endurance running performance in the four sa ironman triathlons investigated. in addition, the interaction between these variants and col5a1 rs12722 appeared to modulate endurance running performance. s afr j sm 2014;26(1):9-14. doi:10.7196/sajsm.523 collagen gene interactions and endurance running performance k o’connell,1 bsc (hons); m posthumus,1 phd; m collins,1,2 phd 1 mrc/uct research unit for exercise science and sports medicine, university of cape town, south africa 2 medical research council, cape town, south africa corresponding author: m collins (malcolm.collins@uct.ac.za) the col5a1 and col6a1 genes encode the α1 chains of types v and vi collagen, respectively.[1-3] both types v and vi collagen are known to regulate collagen fibrillogenesis.[5-7] furthermore, the col5a1 tt genotype of single nucleotide polymorphism (snp) rs12722 c/t and the col6a1 tt genotype of snp rs35796750 t/c have been associated with improved endurance running and endurance cycling performance, respectively, during the south african (sa) ironman triathlon.[4] the association between the col5a1 rs12722 tt and rs71746744 (-/aggg) aggg/aggg genotypes and improved endurance running performance was later replicated in a road running event.[4] in addition, it has been proposed that both col5a1 variants, located in a functional region of the col5a1 3'-untranslated region (utr), regulate type v collagen production.[8] specifically, the rs12722 t and rs71746744 aggg allele of col5a1 are associated with increased col5a1 mrna stability, which may lead to increased levels of type v collagen α1 chain synthesis.[8] increased type v collagen production may affect normal collagen fibrillogenesis and alter the mechanical properties of the tissue, leading to improved endurance performance.[9] similarly to types v and vi collagen, types iii and xii are also implicated in fibrillogenesis.[6,7,10-12] the α1 chains of types iii and xii collagen are encoded by the col3a1 and col12a1 genes, respectively. the non-synonymous col3a1 rs1800255 a/g and col12a1 rs970547 a/g variants within these genes are also associated with a number of multifactorial soft tissue phenotypes.[4,13,14] furthermore, col3a1 rs1800255 and col12a1 rs970547 are both proposed to be functional. [14,15] specifically, the alanine to threonine change at position 698 of the α1(iii) chain, as a result of col3a1 rs1800255, could affect the tensile strength of type iii collagen fibres.[14] in addition, functional bioinformatics analysis of col12a1 rs970547 revealed that the resulting glycine to serine change is potentially damaging to the α1(xii) chain.[15] therefore, since types iii and xii are implicated in fibrillogenesis like types v and vi, it may be proposed that common, potentially functional variants within the col3a1 and col12a1 genes may also be associated with athletic endurance performance. objectives the primary objective of our study was to determine whether col3a1 rs1800255 and col12a1 rs970547, like col5a1 rs12722 and col6a1 rs3579 6750, are associated with athletic endurance performance in the participants of four sa ironman triathlon events. we hypothesised, due to the proposed functional effects of these variants, that the col3a1 rs1800255 gg and col12a1 rs970547 aa genotypes are associated with improved endurance performance. the secondary objective was to investigate gene-gene interactions between col3a1 rs1800255 and col12a1 rs970547, and previously associated collagen genes where appropriate, and endurance performance. we hypothesised that the g+a pseudo-haplotype is associated with improved endurance performance, and that the col5a1 rs12722 t and col6a1 rs35796750 t alleles, if included in gene-gene interactions mailto:malcolm.collins@uct.ac.za 10 sajsm vol. 26 no. 1 2014 with col3a1 rs1800255 and col12a1 rs970547, contributes to interactions for endurance running and cycling, respectively. methods a total of 661 white, male participants were recruited from four sa ironman triathlon events for this genetic case-control association study, using previously outlined recommendations.[16,17] participants were recruited at the registration of either the 2000 (n=96) and 2001 (n=294) events held in gordon’s bay (~50 km from cape town) or the 2006 (n=219) and 2007 (n=52) port elizabeth (pe) events (~750 km east of cape town). all participants were required to complete the event for inclusion in the study. for participants who entered more than one event, only data from one race year was used, since their overall finishing times were similar (data not shown). race results were obtained from the race organisers and participants were divided into three equal tertiles based on their finishing times for the 3.8 km swim, 180 km cycle, 42.2 km run and overall race. the fastest triathletes were placed into the fast tertile, those who finished in the mid-field were placed in the middle tertile, and the slowest triathletes were placed into the slow tertile. study approval was granted by the human research ethics committee, faculty of health sciences, university of cape town, and the race organisers. all participants completed informed consent forms and a physical activity questionnaire. participants of the pe subgroup completed training history questionnaires; this was not documented at the events in gordon’s bay. since training data were obtained during the pe events, the event priority for the participants who had completed more than one event was 2006, followed by 2007 and finally 2001, which had a larger, more complete dataset than the 2000 event. blood collection and dna extraction at event registration, ~4.5 ml of venous blood was collected from each participant into an ethylenediaminetetraacetic acid vacutainer tube by venipuncture of a forearm vein. samples were stored at 4°c until dna was extracted, as previously described, with minor modifications.[18] all analyses were performed at the uct/mrc research unit for exercise science and sports medicine, university of cape town. col3a1 rs1800255 genotyping genotyping of col3a1 rs1800255 was performed using a customdesigned, fluorescence-based taqman polymerase chain reaction (pcr) assay (applied biosystems, usa). allele-specific probes and flanking primer sets (sequences available on request) were used along with a pre-made pcr mastermix containing amplitaq dna polymerase gold (applied biosystems, usa) in a final reaction volume of 8 µl. the pcr cycling comprised a 10 min heat activation step (95°c) followed by 40 cycles of 15 s at 92°c and 1 min at 60°c. the reactions were performed using a xp thermal cycler (block model xp-g, bioer technology co., japan). genotypes were determined by end-point fluorescence using a 7900 ht fast real-time pcr system and sds software (version 2.3). col12a1 rs970547 genotyping col12a1 rs970547 was genotyped as previously described.[19] briefly, fragments containing col12a1 rs970547 were amplified by pcr. the pcr products were digested with alui to produce 599 and 16 bp fragments for the g allele and 460, 139 and 16 bp fragments for the a allele. the fragments were resolved, together with a 100 bp dna ladder, on a 6% non-denaturing polyacrylamide gel and visualised by syber gold staining (invitrogen molecular probestm, usa). the gels were photographed under ultraviolet light using a uvitec photodocumentation system (uvitec limited, uk). statistics continuous variables were compared between genotype groups using one-way analysis of variance (anova) tests. chi-squared or fisher’s tests were used to compare categorical variables. basic descriptive statistical analysis and frequencies were determined using statistica (version 11) and graphpad instat (version 6). inferred pseudohaplotypes between gene variants were tested using hapstat (version 3.0). hardy-weinberg equilibrium status was determined using genepop (version 4.0.10; http://genepop.curtin.edu.au). statistical significance was assumed at p<0.05. results participant characteristics mean ± standard deviation (sd) participant age, height, weight and body mass index (bmi) were 36.1±8.3 years (n=659), 180.5±6.6 cm (n=559), 78.6±9.4 kg (n=586) and 24.0±2.3 kg/m2 (n=555), respectively. approximately 65% were sa-born and 81% were sa residents at the time of recruitment. the general characteristics of participants from each event are reported in table s1 (online supplementary material). participants from the gordon’s bay events (2000 and 2001; mean±sd age 34.7±7.9 years; n=390) were significantly younger (p<0.001) than those recruited from the pe events (2006 and 2007; mean±sd age 38.2±8.4 years; n=269) (table s1). significantly fewer (p=0.002 and p=0.037) sa-born participants competed in the 2000 (53%; n=50) and 2001 (64%; n=185) events than in the 2006 event (73.3%; n=118) (table s1). significantly fewer (p=0.002) sa-resident participants competed in the 2001 event (75.7%; n=215) than in the 2006 event (86.8%; n=190) (table s1). no genotype effects were identified between any of the participant characteristics and the col3a1 rs1800255 or col12a1 rs970547 variants (data not shown). both col3a1 rs1800255 (p=0.428) and col12a1 rs970547 (p=0.062) were in hardy-weinberg equilibrium. participant training history table 1 summarises self-reported training history data, characterising the 15 weeks prior to each event, collected at the 2006 and 2007 pe sa ironman triathlon events. although probably not biologically relevant, the col3a1 rs1800255 variant was significantly (p=0.002) associated with swim training duration (h/week). participants with a col3a1 rs1800255 ga genotype (3.4±1.6 h/week) trained significantly (p=0.001) more than participants with a col3a1 rs1800255 gg (2.8±1.0 h/week) or aa (2.3±0.9 h/week) genotype. the distance (km/week) and duration (h/week) trained for the cycle, run and combined components (swim, cycle and run) were not significantly associated with col3a1 rs1800255 (table 1). furthermore, no significant associations were identified between col12a1 rs970547 and distance or duration trained for the swim, cycle, run or combined tertiles (table 1). col3a1 rs1800255 and col12a1 rs970547 and performance the col3a1 rs1800255 and col12a1 rs970547 variants were not significantly associated with overall finishing time or time taken to http://genepop.curtin.edu.au sajsm vol. 26 no. 1 2014 11 table 1. self-reported training history for the col3a1 rs1800255 and col12a1 rs970547 genotypes of the pe subgroup variable* all (n=187) col3a1 rs1800255 p-valuegg (n=97) ga (n=73) aa (n=17) training (km/week), mean±sd (n) swim 6.4±3.0 (185) 6.4±2.8 (95) 6.5±3.2 (73) 6.1±3.1 (17) 0.857 cycle 224.3±84.9 (170) 218.2±92.9 (85) 232.0±76.5 (69) 223.8±76.2 (16) 0.606 run 45.7±18.0 (182) 47.0±20.4 (92) 44.8±13.3 (73) 42.4±21.6 (17) 0.535 combined† 236.9±85.8 (155) 230.2±95.6 (76) 245.3±75.2 (63) 235.3±77.3 (16) 0.588 training (h/week), mean±sd (n) swim 3.0±1.3 (184) 2.8±1.0 (97) 3.4±1.6 (70) 2.3±0.9 (17) 0.002* cycle 8.1±2.9 (171) 8.1±3.2 (89) 8.2±2.5 (66) 7.8±2.9 (16) 0.875 run 4.5±1.7 (174) 4.6±1.9 (92) 4.5±1.4 (65) 4.1±1.8 (17) 0.575 combined† 15.4±4.8 (162) 15.5±4.8 (85) 15.6±3.7 (61) 14.3±4.5 (16) 0.568 variable* all (n=207) col12a1 rs970547 p-valueaa (n=120) ag (n=82) gg (n=5) training (km/week), mean±sd (n) swim 6.4±3.0 (207) 6.3±2.8 (120) 6.7±3.2 (82) 5.6±1.5 (5) 0.531 cycle 222.7±83.3 (190) 216.9±83.6 (110) 231.6±82.8 (75) 218.7±90.4 (5) 0.499 run 46.3±17.8 (203) 44.9±16.6 (117) 48.5±19.6 (81) 44.0±9.6 (5) 0.371 combined† 236.5±83.6 (174) 229.8±82.6 (97) 246.1±84.8 (72) 229.5±89.9 (5) 0.449 training (h/week), mean±sd (n) swim 3.0±1.5 (206) 3.0±1.7 (119) 3.1±1.4 (82) 2.3±0.7 (5) 0.513 cycle 8.9±12.8 (190) 9.5±16.6 (110) 8.2±2.9 (75) 7.6±2.1 (5) 0.752 run 4.9±3.1 (194) 4.9±3.7 (113) 4.8±2.0 (76) 4.3±0.4 (5) 0.896 combined† 15.5±4.4 (180) 15.3±4.3 (103) 15.8±4.7 (72) 14.2±2.3 (5) 0.607 pe = port elizabeth; sd = standard deviation. * statistically significant (p<0.05). † combined = swim, cycle and run. table 2. finishing times for the col3a1 rs1800255 and col12a1 rs970547 genotypes in the 3.8 km swim, 180 km cycle, 42.2 km run and overall triathlon component all (n=642) col3a1 rs1800255 genotype p-valuegg (n=333) ga (n=265) aa (n=44) 3.8 km swim (min), mean±sd (n) 77.2±17.4 (629) 77.4±17.3 (326) 76.6±17.6 (259) 79.7±17.2 (44) 0.535 180 km cycle (min), mean±sd (n) 393.7±42.0 (615) 394.0±42.7 (317) 392.2±41.6 (254) 399.4±39.9 (44) 0.565 42.2 km run (min), mean±sd (n) 288.4±49.1 (620) 285.9±50.2 (324) 289.9±47.4 (253) 297.8±51.1 (43) 0.264 overall (min), mean±sd (n) 767.8±95.2 (642) 765.5±96.7 (333) 767.4±93.6 (265) 787.1±94.2 (44) 0.369 triathlon component all (n=629) col12a1 rs970547 genotype p-valueaa (n=344) ag (n=255) gg (n=30) 3.8 km swim (min), mean±sd (n) 78.5±17.6 (614) 78.8±17.1 (334) 78.2±17.9 (251) 76.9±20.4 (29) 0.800 180 km cycle (min), mean±sd (n) 395.2±41.5 (600) 393.8±39.8 (330) 397.6±43.2 (243) 391.6±47.3 (27) 0.504 42.2 km run (min), mean±sd (n) 290.1±49.7 (609) 289.0±50.7 (331) 290.8±49.3 (249) 297.0±40.7 (29) 0.681 overall (min), mean±sd (n) 771.8±94.7 (629) 768.8±91.4 (344) 775.3±98.9 (255) 776.5±97.8 (30) 0.677 12 sajsm vol. 26 no. 1 2014 complete any of the individual components (3.8 km swim, 180 km cycle or 42.2 km run) of the 226 km triathlon (table 2). furthermore, when participants were grouped into performance tertiles, no significant differences were identified for col3a1 rs1800255 or col12a1 rs970547 genotype distributions between the groups in terms of the overall finishing time or time taken to complete any of the individual components of the triathlon (table 3). gene-gene interactions and performance since there were no independent associations of the col3a1 and col12a1 variants with endurance performance, inferred pseudohaplotypes between col3a1 rs1800255 g/a and col12a1 rs970547 a/g were constructed. all four inferred pseudo-haplotypes were identified for the overall finishing time, as well as for the time taken to complete the individual components of the triathlon. for the overall tertiles, the major g+a-inferred pseudo-haplotype was significantly (p=0.007 and p=0.029) over-represented in the fast tertile (58%; n=149) when compared with the middle (55%; n=140) and slow (50%; n=127) tertiles, respectively (fig. 1d). when the individual components of the triathlon were analysed, the major g+a-inferred pseudo-haplotype was significantly (p=0.010 and p=0.027) over-represented in the fast run tertile (58.7%; n=144) when compared with the middle (54%, n=131) and slow (50%; n=114) run tertiles, respectively (fig. 1c). no significant associations were identified between the inferred pseudohaplotypes and the swim (fig. 1a) or cycling (fig. 1b) components of the triathlon. since this association was identified for the run component of the triathlon, and col5a1 rs12722 was previously associated with the run component in this cohort,[4] inferred pseudo-haplotypes between col3a1 rs1800255 g/a, col5a1 rs12722 t/c and col12a1 rs970547 a/g were constructed (fig. 2). all eight inferred pseudo-haplotypes were identified. the major g+t+a-inferred pseudo-haplotype was again significantly (p=0.022) over-represented in the fast run tertile (35%; n=86) compared with the slow run tertile (29%; n=67) (fig. 2). furthermore, when the cycling component of the triathlon was investigated with inferred pseudo-haplotypes constructed from col3a1 rs1800255, col6a1 rs35796750 and col12a1 rs970547, no significant associations were identified (fig. 3). discussion the main novel finding of this study was that the col3a1 rs1800255 (g/a) and col12a1 rs970547 (a/g) variants interacted to modulate endurance running performance in the four sa ironman triathlon events. no significant independent associations were identified between these gene variants and the time taken to complete the overall race, or the 3.8 km swim, 180 km cycle or 42.2 km run components. 0 10 20 30 40 fr eq u en cy , % fast middle slow 50 60 a+aa+gg+ag+g 44 50 41 142 128 123 19 17 13 50 51 52 a 0 10 20 30 40 fr eq u en cy , % 50 60 a+aa+gg+ag+g 43 41 45 141 130 114 18 16 13 46 58 46 b 0 10 20 30 40 fr eq u en cy , % 50 60 a+aa+gg+ag+g 41 42 50 144 131 114 16 16 15 44 55 52 c 0 10 20 30 40 fr eq u en cy , % 50 60 a+aa+gg+ag+g 46 39 56 149 140 127 19 15 17 42 62 57 d * p=0.010 † p=0.027 † * * p=0.007 † p=0.029 † * fig. 1. frequency distributions of inferred pseudo-haplotypes constructed from col3a1 rs1800255 and col12a1 rs970547 between the fast, middle and slow tertiles in terms of: (a) time taken to complete the swim component of the triathlon; (b) time taken to complete the cycling component of the triathlon; (c) time taken to complete the run component of the triathlon; and (d) overall time taken to complete the triathlon. the number of participants is indicated above each column. (* fast v. slow tertile; † fast v. middle tertile.) sajsm vol. 26 no. 1 2014 13 previously, we showed the association of col5a1 rs12722 (t/c) and col6a1 rs35796750 (t/c) with endurance running and endurance cycling performance, respectively, in the sa ironman triathlon.[4] furthermore, variants within the col5a1 3'-utr, including rs12722, are proposed to alter the expression of type v collagen, thereby modulating normal fibrillogenesis and resulting in changes to the collagen fibril architecture, structure and mechanical properties. [9] similarly, col6a1 rs35796750 is proposed to result in aberrant splicing of col6a1 mrna, which may also affect the role of type vi collagen in normal fibrillogenesis.[20] both type iii and xii collagens are also implicated in fibrillogenesis.[10,12] like col5a1 and col6a1, common variants within the col3a1 and col12a1 genes are associated with soft tissue phenotypes[13,14,19] and the proteins that these genes encode are implicated in fibrillogenesis.[6,7,10-12] therefore, we proposed that common variants within the col3a1 and col12a1 genes, namely rs1800255 and rs35796750, could be associated with endurance performance in the sa ironman triathlons, in a similar manner proposed for col5a1 rs12722 and col6a1 rs35796750. despite the rationale outlined above, no independent associations were identified between col3a1 rs1800255 or col12a1 rs970547 and endurance swimming, cycling, running and overall performance in the triathlons. however, when inferred pseudo-haplotypes were constructed from col3a1 rs1800255 and col12a1 rs970547, significant genegene interactions were identified. specifically, participants with the major g+a pseudo-haplotype were significantly over-represented in the fast tertile, compared with the middle and slow tertiles, for overall finishing time, as well as for the running component of the triathlon. furthermore, since the col5a1 rs12722 variant was previously associated with endurance running,[4] additional gene-gene inter actions between col3a1 rs1800255, col5a1 rs12722 and col12a1 rs970547 were investigated. again, participants with the major g+t+a pseudohaplotype were significantly over-represented in the fast tertile, compared with the slow tertile, for only the running component of the triathlon. this implicates col3a1 and col12a1, as well as their interaction with col5a1, as potential markers for endurance running performance. additional studies should investigate these genes in true endurance running events, such as marathons, to confirm the findings of our study. furthermore, since no single variant-independent associations were identified for col3a1 rs1800255 and col12a1 rs970547, these findings highlight the importance of gene-gene interactions when investigating multigenic complex traits such as endurance performance. finally, no significant associations were identified between the cycling component of the triathlon and inferred pseudo-haplotypes constructed from col3a1 rs1800255, col6a1 rs35796750 and col12a1 rs970547. study limitations study limitations include the lack of training data for the 2000 and 2001 gordon’s bay events, as well as the lack of data on other important table 3. performance tertiles for the col3a1 rs1800255 and col12a1 rs970547 genotypes in the 3.8 km swim, 180 km cycle, 42.2 km run and overall 3.8 km swim col3a1 rs1800255 genotype, % (n) p-value col12a1 rs970547 genotype, % (n) p-valuegg (n=333) ga (n=265) aa (n=44) aa (n=344) ag (n=255) gg (n=30) fast 52.7 (119) 40.7 (92) 6.6 (15) 0.803 54.8 (115) 41.0 (86) 4.2 (9) 0.704 middle 50.7 (104) 43.4 (89) 5.9 (12) 50.8 (102) 44.2 (89) 5.0 (10) slow 52.0 (103) 39.4 (78) 8.6 (17) 57.6 (117) 37.4 (76) 5.0 (10) 180 km cycle col3a1 rs1800255 genotype, % (n) p-value col12a1 rs970547 genotype, % (n) p-valuegg (n=333) ga (n=265) aa (n=44) aa (n=344) ag (n=255) gg (n=30) fast 53.0 (115) 41.9 (91) 5.1 (11) 0.506 55.9 (114) 39.2 (80) 4.9 (10) 0.796 middle 48.4 (103) 42.7 (91) 8.9 (19) 56.7 (118) 39.9 (83) 3.4 (7) slow 53.5 (99) 38.9 (72) 7.6 (14) 52.4 (98) 42.3 (80) 5.3 (10) 42.2 km run col3a1 rs1800255 genotype, % (n) col12a1 rs970547 genotype, % (n) p-valuegg (n=333) ga (n=265) aa (n=44) p-value aa (n=344) ag (n=255) gg (n=30) fast 56.4 (119) 38.4 (104) 5.2 (11) 0.565 56.4 (114) 40.1 (81) 3.5 (7) 0.461 middle 50.0 (104) 41.8 (87) 8.2 (17) 56.5 (117) 39.1 (81) 4.4 (9) slow 50.3 (101) 42.3 (85) 7.5 (15) 50.0 (100) 43.5 (87) 6.5 (13) 226 km overall col3a1 rs1800255 genotype, % (n) p-value col12a1 rs970547 genotype, % (n) p-valuegg (n=333) ga (n=265) aa (n=44) aa (n=344) ag (n=255) gg (n=30) fast 56.6 (120) 39.2 (83) 4.2 (9) 0.277 54.2 (109) 41.3 (83) 4.5 (9) 0.185 middle 48.4 (103) 43.1 (92) 8.5 (18) 60.6 (126) 36.1 (75) 3.3 (7) slow 50.7 (110) 41.5 (90) 7.8 (17) 49.6 (109) 44.1 (97) 6.3 (14) 14 sajsm vol. 26 no. 1 2014 extrinsic factors influencing athletic ability, (e.g. diet). the inclusion of data regarding training and intrinsic/extrinsic factors into a multivariate analysis model in future studies, including the gene variants investigated here, would provide additional insight into possible interactions that may further explain the inter-individual differences in endurance performance. conclusion our main novel finding was that the col3a1 rs1800255 and col12a1 rs970547 variants interacted to modulate endurance running performance in the four sa ironman triathlons investigated. furthermore, these variants also interacted with col5a1 rs12722 to modulate endurance running performance. this implicates col3a1 and col12a1 as potential markers for endurance running performance. funding acknowledgements. this research was supported in part by the national research foundation (nrf), the medical research council of south africa and the university of cape town. mp was supported by the thembakazi trust. references 1. macarthur dg, north kn. genes and human elite athletic performance. hum genet 2005;116(5):331339. [http://dx.doi.org/10.1007/s00439-005-1261-8] 2. bray ms, hagberg jm, perusse l, et al. the human gene map for performance and health-related fitness phenotypes: the 2006 2007 update. med sci sports exerc 2009;41(1):35-73. 3. eynon n, ruiz jr, oliveira j, duarte ja, birk r, lucia a. genes and elite athletes: a roadmap for future research. j physiol 2011;589(13):3063-3070. [http:// dx.doi.org/10.1113/jphysiol.2011.207035] 4. o'connell k, saunders cj, collins m. collagen gene sequence variants in exercise-related traits. cejssm 2013;1(1):3-17. 5. birk de. type v collagen: heterotypic type i/v collagen interactions in the regulation of fibril assembly. micron 2001;32(3):223-237. 6. minamitani t, ikuta t, saito y, et al. modulation of collagen fibrillogenesis by tenascin-x and type vi collagen. exp cell res 2004;298(1):305-315. [http:// dx.doi.org/10.1016/j.yexcr.2004.04.030] 7. olsen br. new insights into the function of collagens from genetic analysis. curr opin cell biol 1995;7(5):720-727. 8. laguette mj, abrahams y, prince s, collins m. sequence variants within the 3'-utr of the col5a1 gene alters mrna stability: implications for musculoskeletal soft tissue injuries. matrix biol 2011;30(5-6):338-345. 9. collins m, posthumus m. type v collagen genotype and exercise-related phenotype relationships: a novel hypothesis. exerc sport sci rev 2011;39(4):191-198. [http://dx.doi.org/10.1097/jes.0b013e318224e853] 10. fleischmajer r, perlish js, burgeson re, shaikh-bahai f, timpl r. type i and type iii collagen interactions during fibrillogenesis. ann n y acad sci 1990;580:161175. 11. liu x, wu h, byrne m, krane s, jaenisch r. type iii collagen is crucial for collagen i fibrillogenesis and for normal cardiovascular development. proc natl acad sci 1997;94(5):1852-1856. 12. young bb, zhang g, koch m, birk de. the roles of types xii and xiv collagen in fibrillogenesis and matrix assembly in the developing cornea. j cell biochem 2002;87(2):208-220. [http://dx.doi.org/10.1002/ jcb.10290] 13. chou ht, hung js, chen yt, wu jy, tsai fj. association between col3a1 collagen gene exon 31 polymorphism and risk of floppy mitral valve/mitral valve prolapse. int j cardiol 2004;95(2-3):299-305. [http://dx.doi.org/10.1016/j.ijcard.2003.05.026] 14. kluivers kb, dijkstra jr, hendriks jc, lince sl, vierhout me, van kempen lc. col3a1 2209g>a is a predictor of pelvic organ prolapse. int urogynecol j pelvic floor dysfunct 2009;20(9):1113-1118. [http:// dx.doi.org/10.1007/s00192-009-0913-y] 15. kumar p, henikoff s, ng pc. predicting the effects of coding non-synonymous variants on protein function using the sift algorithm. nat protoc 2009;4(7):10731081. [http://dx.doi.org/10.1038/nprot.2009.86] 16. little j, higgins jp, ioannidis jp, et al. strengthening the reporting of genetic association studies (strega) – an extension of the strobe statement. eur j clin invest 2009;39(4):247-266. 17. von elm e, altman dg, egger m, pocock sj, gotzsche pc, vandenbroucke jp. the strengthening the reporting of observational studies in epidemiology (strobe) statement: guidelines for reporting observational studies. plos med 2007;4(10):e296. [http://dx.doi.org/10.1371/journal.pmed.0040296] 18. mokone gg, schwellnus mp, noakes td, collins m. the col5a1 gene and achilles tendon pathology. scand j med sci sports 2006;16(1):19-26. 19. posthumus m, september av, o’cuinneagain d, van der mer we w, schwellnus mp, collins m. the association between the col12a1 gene and anterior cruciate ligament ruptures. br j sports med 2010;44(16):1160-1165. [http://dx.doi.org/10.1136/ bjsm.2009.060756] 20. tanaka t, ikari k, furushima k, et al. genomewide linkage and linkage disequilibrium analyses identify col6a1, on chromosome 21, as the locus for ossification of the posterior longitudinal ligament of the spine. am j hum genet 2003;73(4):812-822. 0 10 20 30 40 g + c + g g + c + a g + t+ g g + t+ a a + c + g a + c + a a + t+ g a + t+ a fr eq u en cy , % run fast run middle run slow 20 23 23 67 51 48 24 20 27 86 80 67 1 6 9 20 26 23 13 6 27 29 29 9 *p=0.022 * fig. 2. frequency distributions of inferred pseudo-haplotypes constructed from col3a1 rs1800255, col5a1 rs12722 and col12a1 rs970547 between the fast, middle and slow tertiles in the time to complete the run component of the triathlon. the number of participants is indicated above each column. (* fast v. slow tertile.) 0 10 20 30 40 g + c + g g + c + a g + t+ g g + t+ a a + c + g a + c + a a + t+ g a + t+ a fr eq u en cy , % cycling fast cycling middle cycling slow 22 17 16 67 45 56 21 24 29 74 85 59 5 11 8 13 32 25 13 5 6 33 26 21 fig. 3. frequency distributions of inferred pseudo-haplotypes constructed from col3a1 rs1800255, col6a1 rs35796750 and col12a1 rs970547 between the fast, middle and slow tertiles in the time to complete the cycling component of the triathlon. the number of participants is indicated above each column. http://dx.doi.org/10.1007/s00439-005-1261-8] http://dx.doi.org/10.1113/jphysiol.2011.207035] http://dx.doi.org/10.1113/jphysiol.2011.207035] http://dx.doi.org/10.1016/j.yexcr.2004.04.030] http://dx.doi.org/10.1016/j.yexcr.2004.04.030] http://dx.doi.org/10.1097/jes.0b013e318224e853] http://dx.doi.org/10.1002/jcb.10290] http://dx.doi.org/10.1002/jcb.10290] http://dx.doi.org/10.1016/j.ijcard.2003.05.026] http://dx.doi.org/10.1007/s00192-009-0913-y] http://dx.doi.org/10.1007/s00192-009-0913-y] http://dx.doi.org/10.1038/nprot.2009.86] http://dx.doi.org/10.1371/journal.pmed.0040296] http://dx.doi.org/10.1136/bjsm.2009.060756] http://dx.doi.org/10.1136/bjsm.2009.060756] sajsm vol. 26 no. 1 2014 15 ta bl e s1 . g en er al c ha ra ct er is ti cs fo r th e sa ir on m an tr ia th lo n pa rt ic ip an ts r ec ru it ed a t r eg is tr at io n of th e 20 00 a nd 2 00 1 ev en ts in g or do n’ s b ay o r th e 20 06 a nd 2 00 7 po rt e liz ab et h ev en ts v ar ia bl e a ll (n =6 59 ) 20 00 e ve nt (n =9 6) 20 01 e ve nt (n =2 94 ) 20 06 e ve nt (n =2 19 ) 20 07 e ve nt (n =5 0) pva lu e a ge (y ea rs ), m ea n± sd (n ) 36 .1 ±8 .3 (6 59 ) 34 .5 ±7 .2 (9 6) 34 .7 ±8 .1 (2 94 ) 38 .2 ±8 .6 (2 19 ) 38 .4 ±7 .1 (5 0) <0 .0 01 h ei gh t ( cm ), m ea n± sd (n ) 18 0. 5± 6. 6 (5 59 ) 18 0. 5± 7. 4 (8 5) 18 0. 5± 6. 5 (2 67 ) 18 0. 3± 6. 4 (1 58 ) 18 1. 4± 6. 8 (4 9) 0. 79 4 w ei gh t ( kg ), m ea n± sd (n ) 78 .6 ±9 .4 (5 86 ) 77 .5 ±1 0. 2 (9 4) 78 .8 ±8 .7 (2 74 ) 78 .2 ±9 .3 (1 66 ) 80 .9 ±1 1. 2 (5 2) 0. 19 6 b m i ( kg /m 2 ) , m ea n± sd (n ) 24 .0 ±2 .3 (5 55 ) 23 .7 ±2 .4 (8 5) 24 .0 ±2 .1 (2 64 ) 24 .0 ±2 .2 (1 57 ) 24 .7 ±3 .2 (4 9) 0. 08 4 c ou nt ry o f b ir th , % (n ) s ou th a fr ic a 65 .0 (3 88 ) 53 .2 (5 0) 63 .6 (1 85 ) 73 .3 (1 18 ) 68 .6 (3 5) 0. 01 1 c ou nt ry o f r es id en ce , % (n ) s ou th a fr ic a 81 .2 (4 68 ) 85 .7 (1 2) 75 .7 (2 15 ) 86 .8 (1 90 ) 86 .3 (4 4) 0. 01 1 sa = s ou th a fr ic an ; b m i = b od y m as s in de x; s d = s ta nd ar d de vi at io n. c p d q u e s t io n n a ir e instructions 1. read the journal. all the answers will be found there. 2. go to www.cpdjournals.co.za to answer questions. accreditation number: mdb001/025/10/2011 (clinical) sajsm questions march 2012 cpd questionnaires must be completed online via www.cpdjournals.co.za. after submission you can check the answers and print your certificate. 1. true (a) or false (b): all studies of fatigue clearly show that it can be attributed to high blood lactate levels. 2. true (a) or false (b): the reason fatigue can be studied easily is because there is a clear concise definition for it. 3. true (a) or false (b): over a century ago, mosso wrote that 'fatigue of the brain reduces the strength of the muscles'. 4. true (a) or false (b): over the years, research has shown that lactic acid is at the origin of all fatigue. 5. true (a) or false (b): a feed-forward mechanism for explaining fatigue attempts to encompass events in which fatigue exists without exhaustion. 6. true (a) or false (b): following the un global summit on non-communicable diseases, the world health organization produced a discussion paper that emphasised the need for increased physical activity. 7. true (a) or false (b): physical activity is among the top 10 targets of the world health organization. 8. true (a) or false (b): the other targets of the world health organization are cardiovascular disease and diabetes, an overall reduction in blood pressure and obesity, reduced smoking, alcohol and dietary salt intake, increased screening for cervical cancer and the elimination of trans-fats from the food supply. 9. true (a) or false (b): chronic, non-communicable diseases account for more than two-thirds of global mortality, at least 50% of which is preventable on the basis of modifiable lifestyle behaviours. 10. true (a) or false (b): in a recent editorial for the british journal of sports medicine, dr robert sallis, chairman of the exercise is medicine advisory board, argued that it is as important for physicians to ask a patient about their exercise habits, as it is to measure their blood pressure. 11. true (a) or false (b): about 17% of the young cricketers surveyed in kwazulu natal had continuous musculoskeletal pain. 12. true (a) or false (b): young cricket players who do not perform sufficient amounts of strength and flexibility training are more predisposed to musculoskeletal pain or injury. 13. true (a) or false (b): studies on adult cricket players show that batsmen and wicket-keepers have the highest risk of injury. 14. true (a) or false (b): most injuries of adult cricket players occur during matches. 15. true (a) or false (b): the injuries of young cricket players occur in similar proportions between 1-day matches and practices. 16. true (a) or false (b): when compared with the injuries of adult cricket players, young cricketers had a greater risk of injury to their backs and trunks. 17. true (a) or false (b): prolonged endurance exercise causes muscle damage that initiates an inflammatory response and subsequent muscle remodelling. 18. true (a) or false (b): the physiological stress after trail running is significantly greater than that which occurs after road running for similar duration. 19. true (a) or false (b): a survey of divers showed that only a few of them had ever experienced symptoms of decompression illness. 20. true (a) or false (b): there is no evidence to suggest that professional divers with high exposure to decompression stress have any resulting intellectual decline. sajsm vol. 27 no. 2 2015 27 parents – their changing role in developing talent for sport one thing almost all parents have in common is the desire to ensure the well-being of their children. this translates into protecting them from adversity while at the same time trying to give them skills that make them successful adults. most parents would like to see their children grow up to be financially independent, happy and contributing to society. among these are also parents who would like to see their children grow up to become sporting superstars. what is the best style of parenting to achieve these goals? many athletes performing at the highest level have acquired the skills they need through adversity. given that there is some truth to this statement, what is the role of parents? this topic was discussed at the recent youth and talent identification and development conference in cape town. a keynote speaker, dr joe baker of york university, canada, raised awareness of the changing role of parents in supporting children in their quest to develop their athletic talent. during the foundation phase of development, the support from the parents is mostly financial. parents with greater means can support their children and give them more opportunities than parents from poorer backgrounds. he discussed the ‘sampling phase’ where the child experiences a variety of sports and the support of parents continues to be financial and emotional. during this phase the parents are also important role models for the child. during the specialising phase, which coincides with adolescence, the role of the parent is mostly financial. the message is clear; the main role of the parent is through the financial support in the early years of development, enabling the child to experience a variety of sports, good coaching, access to facilities and competition. this should ring alarm bells in south africa where the children from poorer households are not going to have the same experiences as children from more affluent homes and therefore are less likely to develop their talent fully. dr baker addressed this by saying that although socioeconomic status had an impact on ‘opening the door, once the door was open it does not have a major effect on the development of talent’. in a society such as ours, with vastly uneven playing fields, the state has a responsibility to narrow the socioeconomic status gap. sporting federations also have a responsibility to create opportunities for children to play and compete that are not dependent on the wealth of the parents. dr baker also showed that elite athletes are more likely to be laterborn children in a family, while non-elite athletes are more likely to be first-born children.[1] although this was a descriptive study, it opens up interesting possibilities for factors contributing to the development of talent. another point made at the conference was the almost nonexistent chance of a young player with sporting talent converting into a high-level professional player. for example, of the 5 8 million youth playing basketball in the usa, only 15 20 progress to play national basketball association level basketball. in south africa, only 0.02% of under-18 rugby players go on to become springboks.[2] to make a visual impression of this statistic, if newland’s stadium was full (about 40 000 people) of under-18 rugby players, only 7 in the stadium would go on to become springboks! so my take-home message from the conference was that there is no simple formula for identif ying and developing talent. parents have a role to play in supporting their children, but this role should mostly be in the background, supporting and paying the bills. adversity is not a problem and can develop important skills that are a prerequisite for success at a high level. however, this is tricky for it is not in the nature of parents to welcome adversity into the lives of their children. the next point from the conference was that children should have the opportunity to sample many sports, but if they come from a poorer environment and do not have other opportunities, then playing only one sport at an early age is a viable option for developing talent. competition that encourages winning-at-all-costs at young ages should be discouraged. failure to do so will compromise skill development and progression for all children – the children who mature early will have an advantage – the children who mature later will be disadvantaged and lost to the system. the most important message for parents was to act as good role models and teach children the importance of physical activity. these lessons, taught well, will have a meaningful impact on how our children grow and incorporate physical activity into their lifestyles. this is surely a noble outcome. 1. hopwood mj, farrow d, macmahon c, baker jj. sibling dynamics and sport expertise. scand j med sci sports 2015 (in press). 2. parker z. factors associated with success in south african rugby union. mphil thesis. cape town: university of cape town, 2013. mike lambert editor-in-chief s afr j sports med 2015;27(2):27. doi:10.7196/sajsm.634 editorial the easy choice suplasyn advert sports journal 2.indd 1 2015/05/28 12:33 pm original research 1 sajsm vol. 35 no.1 2023 creative commons attribution 4.0 (cc by 4.0) international license the role of selected pre-match covariates on the outcome of one-day international (odi) cricket matches k mcewan,1 msc; l pote,3 phd; s radloff,2 phd; sb nicholls,3 phd; c christie,1 phd 1 department of human kinetics and ergonomics, rhodes university, grahamstown, south africa 2 department of statistics, rhodes university, grahamstown, south africa 3 department of sport, outdoor and exercise science, university of derby, england corresponding author: l pote (l.pote@derby.ac.uk) the identification of factors which influence the likelihood of winning through statistical modelling has grown in popularity.[1,2] cricket is the second most popular sport worldwide and predicting the match outcome has been exploited in the betting industry; however, the potential predictive factors of cricket matches have not been extensively researched.[3] this may be because of the multifaceted and inconsistent nature of the game.[4] furthermore, while the sports betting industry is constantly growing (specifically in cricket) and this type of information can be used by bettors, the prediction of the final match outcome may also prove beneficial to team members and coaches.[5,6] it has been suggested that the team management, coach and captain can analyse specific characteristics of cricket matches to predict match performance.[7] in forecasting match results in cricket, factors are categorised under two covariate groups; pre-match, which predicts the outcome prior to the match; and in-play, which predicts the outcome while the match is in progress.[3] pre-match covariates relate to several aspects that have been identified to impact upon match outcome. within cricket, these include but are not limited to, home advantage, team strength, toss outcome, toss decision, and match type. the home advantage concept is based on the phenomenon that teams win more than 50% of their matches on home ground.[8] home advantage has been previously identified in odi matches,[9,10], particularly for india, south africa, australia, sri lanka, new zealand and pakistan.[4] however, it has been suggested that home advantage in cricket has slowly diminished over recent years.[2] this could be due to the emergence of the new twenty20 leagues which provide players with more global exposure.[2] the various factors that contribute to home advantage in sports are familiarity with pitch conditions, travel effects, tactics, crowd factors, umpire bias and psychological changes.[11] however, even though each factor has perceptive appeal and slight empirical support, there is no strong evidence to indicate that any of these factors alone, or in combination, determine a home advantage.[8,12] team strength must be considered and controlled when quantifying the effect of both the home advantage and the coin toss.[13] team strength is normally based on the international cricket council’s (icc) official odi rankings; however, it is often criticised as it uses an ad-hoc points system entirely based on matches won and lost.[14] research has proposed, but has not yet implemented, a weighted teamrank (wtr) method which increases points given to a team when they gain a win against a stronger team as opposed to a win against a weaker team.[14] team strength can also be internally quantified by calculating the quality of each player’s bowling and batting capacity.[10] this information could influence the tactical decisions of a team, depending on the opposition’s dominant ability.[10] the toss decision, weather conditions, and match type are all considered when determining the magnitude of the advantage that winning the toss offers.[1,15] investigating the effect of the coin toss on odi matches, particularly the debate regarding its removal, was completed recently in english county cricket.[16] there is no evidence to suggest that teams gain a winning advantage because of winning the toss in odis.[4,9,10] a small advantage has been seen,[17] but these results were obtained using unreliable statistical means, omitting key statistical procedures, such as odds ratios, confidence intervals, likelihood rest ratios and specific hypothesis testing. furthermore, a disadvantage of winning the coin toss has been seen in day matches.[2] this could indicate that despite the strategic opportunity the toss provides, more teams are prone to making incorrect toss decisions by overand/or underestimating their opposition’s strengths and weaknesses.[2] the decision to bat or bowl first, after being given the opportunity through winning the toss, is mainly dependent on background: the identification of key factors that systematically influence a team’s success is important and has led to the application of statistical models in sport. predicting the outcome of a one day international (odi) cricket match, using only pre-match covariates, has been minimally investigated. objectives: this research sought to investigate the impact that venue, toss outcome, toss decision, and match type have on the chances of winning an odi match. methods: a total of 1228 men’s international odi matches were analysed. a logistic regression model was used to identify the significance of these pre-match covariates on the result of the matches. results: the results varied across all teams, suggesting that there are individualised factors driving these differences and that generalising the impact pre-match covariates have in every team is unrealistic. new zealand and india displayed a significant home advantage effect, whereas australia had a strong tendency towards a significant disadvantage when they won the toss. however, for most teams, toss outcome, toss decision, and match type did not significantly impact the outcome of an odi match. conclusion: new zealand and australia were the most predictable teams, whereas south africa and pakistan were regarded as unpredictable when pre-match covariates were used to forecast the outcome of their odi matches. keywords: cricket, match type, toss decision, toss outcome, venue s afr j sports med 2023;35:1-6. doi: 10.17159/2078-516x/2023/v35i1a15012 http://dx.doi.org/10.17159/2078-516x/2023/v35i1a15012 https://orcid.org/0000-0003-0835-560x https://orcid.org/0000-0003-0727-0014 https://orcid.org/0000-0002-6200-1418 https://orcid.org/0000-0002-1376-5673 https://orcid.org/0000-0003-1371-2616 original research sajsm vol. 35 no.1 2023 2 the team’s bowling and batting ability.[11,18,19] it has been proposed that fast bowlers prefer to bowl first during day games, as there is more moisture on the pitch.[18] however, it has also been suggested that teams such as india, which generally have a bowling line-up dominated by spinners,[17] prefer bowling second, after the pitch has worn down.[18] most teams often decide to bat first because of the unpredictability of the second half of the match possibly being influenced by weather conditions.[4] however, batting second could be an advantage because the team can implement an appropriate strategy to win, as they are cognisant of the run chase target.[10,18] individual venues must also be taken into consideration when making the toss decision, as some pitches favour the side batting first and vice-versa.[20] the weather can also affect the playing conditions and outcome of a match[13,21] ,with results or run targets changing due to the implementation of the duckworth-lewis-stern (dls) method.22] the odi format involves two different match types: dayonly and day-night game.[18] the coin toss is seen to be more crucial in day-night matches as playing conditions are considerably different.[17,18,21] during a day-only game, both teams play entirely under natural light, whereas during a daynight game, artificial lighting is used during the evening.[19] it has been suggested that batting second in day-night games is seen as a disadvantage because the artificial light lessens the visibility of the white ball.[19] however, those who bowl second also experience difficulties in the evening as the dew factor causes poor ball grip, which increases the likelihood of bowling inaccuracy.[13,19] although these pre-match factors influence odi matches, the modelling of these factors has been minimally investigated. additionally, existing research has not performed the necessary diagnostic tests; thus, the validity and reliability of their results are compromised. tests such as the likelihood-ratio test, best model selection (aic), hypothesis testing, odds ratios, and confidence intervals have not previously been included in research studies. however, it is important that these are considered to ensure a robust study design. therefore, the purpose of this study was to construct binary logistic regression models for eight teams as part of the icc, using venue (home/away), toss outcome (win/lose), toss decision (bat first/second) and match type (day/day-night) to predict the outcome of odi matches. this may assist in determining how these variables influence the game, and if they are significant enough to potentially predict the winner before the match commences. methods sample a total of 1228 men’s international odi matches involving south africa, australia, new zealand, sri lanka, england, pakistan, west indies, and india played between january 2007 and july 2017, were selected for analysis. these eight competitors were selected as a sample of convenience as they have regularly competed and are full members of the icc. the period of ten years was chosen to enable an appropriate number of observations to be collected to perform reliable logistic regression analyses. additionally, the odi limitedovers form was selected as (i) there are more win/loss results generated compared to test matches and (ii) it provides a more balanced schedule of regular fixtures between teams. female teams were not considered to have played significantly fewer odis compared to the men, within the selected time period. furthermore, test and t20 matches were also excluded. procedure data regarding four predictors (venue, toss outcome, toss decision, and match type) and one response variable (match outcome) were collected manually from match scorecards, which are openly available via the espn cricinfo website. match type referred to whether a match was a day or day-night game. to control for extraneous factors, data went through a filtration process where matches were excluded if (1) the result ended in a tie or no result, (2) the duckworthlewis/duckworth-lewis-stern method was used, (3) the match took place at a neutral venue, or (4) the umpires were both local. the statistical software r® (version 1.0.153) was used for all data analysis processes. statistical analysis a logistic regression model was constructed to identify the significance of the pre-match covariates (venue [home, away], toss outcome [win, loss], toss decision [bat first, bat second], and match type [day, day-night]), both collectively and individually, for each cricket team in relation to the response variable (match outcome [win, lose]). no multi-comparison correction tests were done and each country was individually critiqued and analysed. the wald chi-squared statistic (z2), which is a χ2 distribution with one degree of freedom, was used to assess whether the individual variables significantly impacted upon match outcome (z2 > 3.84). the odds ratio was also calculated to predict the likelihood of winning an odi while controlling for the other predictors in the model. additionally, after fitting the model for each cricket team, a likelihood ratio test was used to assess whether the variables as a whole significantly impacted match outcome. all significance thresholds were set at 0.05. the best fitted model was selected by identifying the model which had the lowest akaike information criterion (aic) value. this was determined using a stepwise elimination algorithm in both directions (i.e. forward, and backward). mcfadden pseudo r2 was calculated to measure the predictive value of the model. values between 0.2 to 0.4 were considered satisfactory (below 0.2 was considered poor). receiver operating characteristic (roc) curves were also used to visually demonstrate the trade-off between sensitivity and specificity and the area under the roc curve (auroc) was calculated to give a measure of predictive power. the fitted logistic regression curve, represented by equation 1, was used to estimate probabilities for given individual scenarios. (1) scenario-based predictions were also made, for example original research 3 sajsm vol. 35 no.1 2023 purposes, using the models which have the highest predictable power. only past matches played over the same ten-year period between the teams involved in the scenarios were included in the generalised linear model (glm) to make the predictions and demonstrate the overall usability of the process. results logistic regression models output all teams showed positive estimate values, indicating that playing at home had a positive effect on the likelihood of winning an odi game (table 1). however, only australia (z2 = 10.32; p = 0.0013), new zealand (z2 = 9.63; p = 0.0019) and india (z2 = 5.40; p = 0.0202) had significant positive relationships. the odds ratio of australia, new zealand and india indicate that they were 2.85, 3.31 and 2.11 times more likely to win an odi during home games than away games (odds ratio for remaining teams ranged between 1.34 and 1.92). all teams (except india) had negative estimate values indicating that playing day-night games had a negative effect on the likelihood of winning an odi game. however, no significant (p < 0.05) relationship between match type and the outcome of an odi match were found across all teams (table 1). all teams (except the west indies) showed positive estimate values indicating that winning the toss negatively affected the likelihood of winning an odi game (table 2). however, none of these relationships was significant, except australia, which showed a strong tendency towards statistical significance (z2 = 3.82; p = 0.0506). australia’s respective odds ratio of 0.54, indicates that they were the least likely team to win an odi when they won the toss (table 2). south africa, england, pakistan, west indies, and india showed positive estimate values whereas australia, new zealand and sri lanka had negative estimate values. however, no significant (p < 0.05) relationship between the toss decision and the outcome of an odi match was found across all teams (table 2). the variables “venue”, “toss outcome”, “toss decision” and “match type” can collectively be used to forecast the outcome of an odi match for australia (χ2=17.49; p = 0.002) and new zealand (χ2=13.77; p = 0.008). best model selection using only the variable ‘venue’ can be used to best predict the outcome of an odi game for england, sri lanka, west indies, and india. additionally, a model using ‘venue’ and “toss outcome” best predicts the outcome for australia whereas ‘venue’ and ‘match type’ best predict the outcome for new zealand. none of the variables accurately predict the outcome of an odi game for south africa and pakistan (table 3). overall predictive analysis table 4 demonstrates that all teams are unable to strongly table 1. summary of logistic regression model outputs for variable ‘venue’ and ‘match type’ team venue match type estimate z-value z2 p-value odds ratio estimate z-value z2 p-value odds ratio south africa 0.41 1.17 1.36 0.243 1.50 -0.24 -0.66 0.43 0.511 0.79 australia 1.05 3.21 10.32 0.0013* 2.85 -0.15 -0.40 0.16 0.687 0.86 new zealand 1.20 3.10 9.63 0.0019* 3.31 -0.77 -1.79 3.19 0.074 0.49 england 0.51 1.54 2.37 0.124 1.66 -0.13 -0.33 0.12 0.741 0.88 sri lanka 0.51 1.52 2.30 0.129 1.66 -0.15 -0.44 0.20 0.659 0.86 pakistan 0.29 0.78 0.61 0.435 1.34 -0.22 -0.54 0.29 0.590 0.80 west indies 0.65 1.13 1.28 0.259 1.92 -0.21 -0.34 0.11 0.735 0.81 india 0.75 2.32 5.40 0.0202* 2.11 0.065 0.19 0.04 0.850 1.067 * indicates statistical significance (p <0.05) table 2. summary of logistic regression model outputs for variable ‘toss outcome’, and ‘toss decision’ team toss outcome toss decision estimate z-value z2 p-value odds ratio estimate z-value z2 p-value odds ratio south africa -0.20 -0.55 0.30 0.586 0.82 0.14 0.38 0.14 0.707 1.15 australia -0.61 -1.96 3.82 0.0506 0.54 -0.28 -0.86 0.73 0.392 0.76 new zealand -0.13 -0.34 0.11 0.736 0.88 -0.13 -0.34 0.11 0.737 0.88 england -0.019 -0.051 0.003 0.959 0.98 0.065 0.18 0.031 0.860 1.067 sri lanka -0.33 -1.03 1.067 -0.302 0.72 -0.26 -0.83 0.69 0.408 0.77 pakistan -0.22 -0.55 0.31 0.581 0.80 0.54 1.33 1.76 0.185 1.71 west indies 0.29 0.61 0.37 0.543 1.33 0.45 0.97 0.93 0.335 1.57 india -0.10 -0.31 0.094 0.758 0.90 0.38 1.15 1.32 0.252 1.46 original research sajsm vol. 35 no.1 2023 4 classify a win or a loss using the pre-match covariates. the most predictable teams are new zealand (r2 = 0.077; auroc = 0.69) followed by australia (r2 = 0.065; auroc = 0.67). example-based predictive analysis winning the toss has a significant negative effect on australia winning an odi against south africa (z2 = 5.28; p = 0.022). the odds of australia winning an odi game against south africa is only 0.037 times more likely when winning the toss than when losing the toss (table 5). home advantage is significantly seen in new zealand and positively affects the likelihood of winning an odi match against australia (z2= 6.68; p = 0.010). when new zealand play at home, they are 36.33 times more likely to win an odi against australia than when they play away in australia (table 6). the following scenarios (a) and (b) were predicted using models constructed in tables 5 and 6. these models were based on australia and new zealand respectively, since they showed the highest predictive ability (table 3). (a) australia is playing south africa at home and win the toss. australia chooses to bat first and the match format played is a day-night game. what is the probability that australia will win this match? probability = 0.312= 31.2% (b) new zealand are playing australia at home and win the toss. new zealand bat first and the match format played is a day-night game. what is the probability that new zealand will win this match? probability = 0.569= 56.9% discussion only australia (z2 = 10.32; p = 0.0013), new zealand (z2 = 9.63; p = 0.0019) and india (z2 = 5.40; p = 0.0202) present a significant (p < 0.05) positive relationship with playing at home and winning an odi match (table 1). this may be because teams must travel in an eastward direction to play at these venues. research has shown that eastward travel correlates with a reduction in sports performance compared to westward travel.[23] the lack of significant home advantage in most teams could be due to the increased awareness concerning the effects of travel on performance. thus teams travel to away venues earlier, allowing more time to alleviate the adverse effects of jet lag on performance.[23] one can only speculate that the home advantage found in india, who are known for their world-class spin bowlers,[17] could be as a result of their home pitch curated toward favouring their bowling strength.[18] ‘venue’ is found to be an influential variable for australia, new zealand, england, sri lanka, west indies, and india concerning the outcome of an odi match (table 3). as ‘venue’ does not influence south africa and pakistan, one could consider these countries as neutral venues for worldclass tournaments; however, further research is needed regarding this standpoint. furthermore, it needs to be noted that pakistan played most of their home games in the united arab emirates for most of the years over the data collection period. because of the ‘consistency’ of playing their ‘home games’ at the same venue, as well as the fact that certain conditions could be controlled by the team (i.e. pitch conditions), means that this may not have made a massive difference. table 3. summary of results using a stepwise elimination method team best model lowest aic value south africa null 197.11 australia venue + toss outcome 260.41 new zealand venue + match type 172.55 england venue 233.96 sri lanka venue 218.63 pakistan null 194.32 west indies venue 123.70 india venue 228.20 aic, akaike information criterion table 4. mcfadden pseudo r2 and area under the rorc curves for each cricket team team mcfadden pseudo r2 predictive value auroc predictive power south africa 0.014 poor 0.58 worthless australia 0.065 poor 0.67 poor new zealand 0.077 poor 0.69 poor england 0.025 poor 0.60 poor sri lanka 0.012 poor 0.58 worthless pakistan 0.012 poor 0.58 worthless west indies 0.038 poor 0.63 poor india 0.031 poor 0.62 poor mcfadden pseudo r2 values below 0.2 were considered poor. auroc, area under the receiver operating characteristic curve. table 5. logistic regression model for australia vs south africa (n = 25) variable estimate z-value z2 p-value odds ratio intercept -0.71 -0.48 0.23 0.635 0.49 home 1.41 1.30 1.70 0.193 4.077 win toss -3.31 -2.30 5.28 0.022* 0.037 bat first 1.84 1.36 1.85 0.174 6.26 day night -0.016 -0.013 0.001 0.990 0.98 * indicates statistical significance (p <0.05) table 6. logistic regression model for new zealand vs australia (n = 28) variable estimate z-value z2 p-value odds ratio intercept -2.31 -1.46 2.14 0.143 0.099 home 3.59 2.59 6.68 0.010* 36.33 win toss -0.34 -0.31 0.094 0.760 0.71 bat first -1.94 -1.44 2.074 0.150 0.14 day night 1.28 0.90 0.82 0.367 3.58 * indicates statistical significance (p <0.05) original research 5 sajsm vol. 35 no.1 2023 home advantage may also be dependent upon specific opposition teams.[4,9] this is evident with australia, where a significant overall home advantage is seen (table 1); however, no significant home advantage against south africa is observed (table 5). psychologically, a home advantage may have an impact on player positivity[12], which could be the case with australia, new zealand and india, impacting upon performance in relation to specific venues. additionally, due to the increase in international twenty/20 tournaments, players are more accustomed to playing away, potentially reducing the global effect of home advantage.[2] home advantage, however, cannot be generalised for all cricket teams and formats of the game and thus warrants future research regarding the impact of home advantage on performance.[9] lastly, pitch preparation could be another reason for the loss of home-ground advantage. pitch preparation for the shorter formats of the game favours highscoring matches and as a result, annuls the advantage of teams manipulating the pitch to suit their bowlers. winning the toss does not give any statistically significant advantage towards the outcome of odis (table 2).[4,9,10] however, australia has a substantial disadvantage of winning the toss, suggesting that their toss decision is poorly chosen. as most teams have a non-significant negative relationship with the toss, the debate as to whether the toss should be removed or not could be disputed. furthermore, no significant evidence exists regarding winning and the decision of a team choosing bat or bowl first, which could suggest that the toss decision may not impact odi match outcome (table 2).[9,10,18] from a tactical standpoint, it may be beneficial for teams to be cognisant of the relationship their opposition has with batting first to make a more informed decision if the toss is won. for example, this knowledge could be implemented against teams, such as australia, new zealand, and sri lanka, who appear to have a minor negative relationship with batting first (table 2). all teams, except india, had a negative non-significant relationship with day-night matches and winning an odi game (table 1), which correlates with past research.[4] this could mean that specific teams are slightly hindered by the adverse effects of the artificial lighting (visibility) and dew on the ball (affecting grip) during the night session.[13,17,18] a possible resolution is to introduce more night training sessions, which could allow players to adapt to the different conditions experienced between the two match types. predictive ability all team models are of poor predictive power (table 4); however, the predictive value for each team can be increased by using their respective best glm models with the lowest aic (table 3). using only the most influential variables in the models would result in more accurate predictions. this was not investigated in the analyses though as it is beyond the scope of this research paper. of all the teams, new zealand and australia are the most predictable when using the venue, toss outcome, toss decision, and match type as the factors to forecast the outcome of odis. south africa and sri lanka provide no evidence of strong relationships to any of the prematch covariates, which may imply that they are the least predictable teams (table 4). these findings are evident when examining the area under the curve (auc); new zealand and australia have a higher auc compared to south africa, sri lanka, and pakistan. this could be because australia and new zealand, over the 10-year data collection period, had a more stable team structure and playing style. furthermore, they may have had access to data, analysts and technology that assisted in decision-making processes for specific match conditions, i.e. more informed decisions compared to other cricketing nations at the time. australia has a significant, negative relationship (z2 = 5.28; p = 0.022) with winning the toss and winning an odi against south africa (table 5), which could explain the small winning probability of 31.17% seen in scenario (a). additionally, australia is seen to be the least likely team to win an odi when they win the toss than when they lose the toss (odds ratio = 0.54) (table 2). this toss disadvantage could indicate that despite the strategic opportunity the toss provides, australia is mostly prone to making incorrect toss decisions,[2] especially when they play against south africa. new zealand, however, has an extreme home advantage (z2= 6.68; p = 0.010) when competing against australia (table 6). this correlates with home games for new zealand, where playing at home has a significant positive effect on the likelihood of winning an odi match (z2 = 9.63; p = 0.0019; table 1). limitations the overarching venue of a country’s origin in relation to the opposition (home/away) was recorded, with specific individual venues within each country not being considered within the analysis. this becomes an important point to consider, as despite the respective team playing within their own country’s boundaries, specific stadia may have diverse features (e.g. pitch slope), weather conditions (e.g. the area of the location has a higher propensity to rain or high winds), and pitch/outfield types (e.g. fast/slow). the scenarios constructed should also be interpreted with caution, as despite these being the ‘best’ examples, all team models overall were of poor predictive power. lastly, the data was collected over a 10-year period through which team form, players and coaches would have changed. however due to the large sample size of the investigation, as well as random selection, the risk of bias is reduced as well as the fact that logistic regression does not depend on normality. this is an argument that would limit all team sports studies. future directions future qualitative research via questionnaires and interviewbased approaches is arguably warranted to ascertain the athlete’s perspective regarding the impact pre-match covariates has upon team/individual performance and pre-match preparation. additionally, it would be beneficial to make use of binary logistic regression, in conjunction with dynamic logistic regression, during the match as it is probable that this may provide a more accurate prediction of match outcome based upon ongoing events (e.g. deliveries remaining, wickets taken). lastly, this research could be replicated for other formats of the original research sajsm vol. 35 no.1 2023 6 game (i.e. tests and twenty20) to ascertain whether (1) the use of pre-match covariates holds a meaningful predictive power or (2) the toss decision positively or negatively impacts match outcome for the specific opposition (potentially enhancing a captain’s ability to make a more informed batting/bowling decision) within these formats. to conclude, although not in the scope of this study, future research should also consider additional pre-match covariates such as team composition (bowlers, all-rounders, batters) venue, match type and toss decision, as well as other formats (t20, test). further studies could replicate the use of the current method while adjusting the study design based on specifically selected pre-match covariates and match format. conclusion binary logistic regression models were used to investigate the effects of venue, toss outcome, toss decision, and match type on winning an odi match for eight major cricket-playing nations. varying results were found between the nations concerning each discrete pre-match covariate. this could mean that there are individualised factors driving these differences, therefore generalising the impact that pre-match covariates have in every team is unfeasible. home advantage is present in odi cricket; however, significance was only found for australia, new zealand and india. australia had a strong tendency towards a significant disadvantage when winning the toss. however, for most teams, toss outcome, toss decision, and match type did not significantly impact the outcome of an odi match. new zealand and australia were found to be the most predictable teams, whereas south africa and pakistan can be regarded as unpredictable when prematch covariates are used to forecast the outcome of their odi matches. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: we would like to thank mr. j baxter (lecturer in the department of statistics at rhodes university) and prof. l raubenheimer (associate professor at north west university, potchefstroom) for their statistical consultation assistance. author contributions: km and cc; project conception, data collection, data analysis, manuscript draft and review. lp and sn; 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[doi:10.1177/1941738112442340] [pmid: 23016089] https://doi.org/10.1007/978-3-319-02750-0_16 http://www.espncricinfo.com/magazine/content/story/964039.html http://www.espncricinfo.com/magazine/content/story/964039.html original research sajsm vol. 26 no. 2 2014 59 review dietary supplements and chemical agents have been used for a number of decades among athletes striving to achieve increased strength and performance. this has led to a huge, growing market for the food supplement industry. the latter’s products are classified as ‘foods’ rather than drugs and are therefore free of the stringent requirements for registration of pharmaceuticals, i.e. no safety and efficacy data are required prior to registration. during the past decade, some dietary supplements have been shown to contain pharmaceutically active components not adequately identified on their package labels. these pharmaceuticals may have unintentionally entered the product or may have been intentionally added. although the concentrations of these substances may be low and devoid of health or performance-enhancing effects, they may lead to positive doping tests. in part 1 of this two-part review, a selection of the world anti-doping agency-prohibited illegal stimulants, i.e. ephedrine, pseudoephedrine, sibutramine and methylhexaneamine, are discussed. certain food supplement labels do mention the presence of natural sources of illegal stimulants, e.g. ephedra sinica (ephedrine), but do not refer to the chemical entities of ephedrine and its analogues as such. the pharmacological adverse effects of stimulants, in particular those on the cardiovascular system, are briefly reviewed. suggestions for avoiding these pitfalls are made. s afr j sm 2014;26(2):59-61. doi:10.7196/sajsm.552 dietary supplements containing prohibited substances: a review (part 1) p van der bijl, bsc hons (chem), bsc hons (pharmacol), bchd, phd, dsc emeritus professor and former head, department of pharmacology, faculty of medicine and health sciences, stellenbosch university, tygerberg, cape town, south africa; and invited foreign professor, department of pharmacology, pirigov’s russian national research medical university, moscow, russia corresponding author: p van der bijl (pietervanderbijlcpt@gmail.com) while it is well recognised that a balanced diet is the foundation for developing optimal training and performance, competitive sport and strenuous physical activity make demands on the human body beyond its normal physiological range.[1] some athletes may therefore benefit from additional supplements to help maintain homeostasis with adequate nutrients and energy in specific circumstances, especially where food intake or choice is restricted. for this reason, dietary supplements have been used by athletes for many years to boost, even by small margins, their strength and performance. [2-4] pressure to perform and the potential rewards coupled with success are powerful driving forces for many top athletes to continue striving for that chemical competitive edge. for this purpose, they use these dietary supplements as part of their regular training or competition routine, even if the rationale for using these products is not always underpinned by solid evidence-based research.[1] supplements commonly used include vitamins, minerals, protein, creatine and various ergogenic compounds. while some supplements indeed enhance athletic performance, many have no proven benefits, are of uncertain content and purity, and may have serious systemic adverse effects, including death. the practice of using dietary supplements among the population at large and athletes at all levels of competition has led to a huge, continuously growing, multibillion dollar industry with a worldwide market estimated at more than $142 billion in 2011 and expected to rise to $205 billion by 2017.[5] coupled with aggressive marketing techniques in which bold as well as unsubstantiated claims are frequently made, this explosive growth has been further fuelled in many countries worldwide which have acts similar to the dietary supplement health and education act (dshea), which was passed by the us congress in 1994. in essence, these acts allow substances that are marketed as dietary supplements to be regulated as foods rather than as pharmaceuticals. a dietary supplement is a product taken orally that contains a ‘dietary ingredient’ intended to supplement the diet. the ‘dietary ingredients’ in these products may include vitamins, minerals, herbs or other botanicals, amino acids, and substances such as enzymes, organ tissues, glandulars and metabolites.[6] dietary supplements can be extracts or concentrates, and may be found in many forms such as tablets, capsules, softgels, gelcaps, liquids or powders. they can also be in other forms, such as a bar, but if they are, information on the label must not represent the product as a conventional food or a sole item of a meal or diet.[6] whatever their form may be, the dshea places dietary supplements in a special category under the general umbrella of ‘foods’, not drugs, and requires that every supplement be labelled a dietary supplement.[6] other than for pharmaceuticals, in which regulatory authorities scrutinise data on safety and efficacy before giving marketing approval, supplement manufacturers do not have to prove efficacy for their products, providing that they do not claim that their preparations can be used to diagnose, cure, mitigate, treat or prevent diseases. furthermore, manufacturers of dietary supplements do not have to demonstrate their safety, and the burden rests on regulatory authorities to show that a particular product is harmful before steps can be taken to ensure its removal from the market. mailto:pietervanderbijlcpt@gmail.com 60 sajsm vol. 26 no. 2 2014 these dietary supplement regulations have facilitated their availability not only to the population at large and noncompeting amateurs, but especially to professional athletes in whom their use, often in megadoses, is widespread.[7,8] estimated use in the latter group varies between 44% and 100%; however, this very much depends not only on the type of sport but also on the level of competition and age and gender of the athletes.[8-11] large quantities of nutrients, commonly found in normal human diets, are consumed without there being much knowledge of possible health risks and the maximum daily safe doses involved. over the past decade, a new hazard related to dietary supplement use has been identified in that some products, marketed under the aegis of the regulatory requirements for foods, have been shown to contain unapproved pharmaceutically active ingredients. these dietary regulations have allowed manufacturers to bypass the necessity of providing safety and efficacy data for their products. it is of great concern that a wide variety of dietary supplements contain ingredients not adequately chemically identified on their packaging labels. these ingredients, which are sometimes listed as ‘natural’, ‘herbal’ or otherwise, may constitute prohibited substances. they may have inadvertently entered the product, possibly as a result of accidental cross-contamination in manufacturing plants, or may have been intentionally added to the supplement, posing a potential health hazard to all consumers.[4,12] while concentrations of these non-approved substances may be too small to achieve any health or performance-enhancing effects, they may be large enough for athletes to fail a doping test, and scandals appear to be more fre quent.[4] in recent years, there has been an increase in the number of dietary supplements containing unapproved pharmaceutical ingredients, recalled by the food and drug administration.[13] with as many as 150 million citizens in the usa consuming dietary supplements in some form or another, the challenges that are posed by this growing and unregulated industry are enormous. ephedrine and pseudoephedrine although stimulants can easily be detected in laboratories, they are still popular among athletes. because the list of legal and illegal stimulants is extensive, only a selection will be discussed here. studies have shown that certain dietary supplements have con tained prohibited substances such as ephedrine and its analogues (pseudoephedrine, methylephedrine, etc.), caffeine, 3,4-methylenedioxy-n-methylamphetamine (mdma, or ‘ecstasy’) and other amphetamine-related compounds, which may or may not be declared on packaging labels.[12] ephedrine and its congeners are used as nasal decongestants and as pressor agents for hypotension. while caffeine is no longer considered a prohibited substance by the world anti-doping agency (wada) since 2004, the use of ephedrine and its analogues and mdma is banned during competition by this organisation.[14] on certain food supplement labels, natural sources of ephedrine, e.g. ephedra sinica – a species of ephedra (ma huang), which contains the alkaloids ephedrine and pseudoephedrine – are mentioned instead of the chemical entities of ephedrine and its analogues. similarly, synephrine is obtained from citrus aurantium. both plant products have been found in dietary supplements that were labelled as ‘ephedrine free’. apart from the doping infringement aspects of supplements containing prohibited stimulants, there are potential health risks involved that should not be ignored. ephedrine has structural similarities with amphetamine and therefore has similar modes of action and a comparable side-effect profile. both ephedrine and pseudoephedrine are stimulants, but they affect physical achievement differently. ephedrine adversely affects running time over 10 km, but anaerobic performance of athletes increases.[15,16] supporting evidence found in a meta-analysis of eight studies was, however, insufficient to demonstrate clear benefits in performance with ephedrine.[17] similarly, improvements in fatigue and cycling performance with pseudoephedrine ingestion could not be found, but in a limited study an improvement in running times over 1.5 km following the use of this pharmaceutical agent was shown.[18-20] adverse effects of ephedrine may be serious. a twoto threefold risk of anxiety, increased irritability and agitation (psychiatric symptoms), insomnia, tremors (autonomic system symptoms) and heart palpitations (cardiac symptoms) were found on analysis of 71 case reports and 50 clinical trials.[17] in the foregoing analysis of cases of death, myocardial infarctions, cerebrovascular accidents, seizures and psychoses were found in some reports. regarding pseudoephedrine anxiety, gastrointestinal disturbances and tremors have been reported.[21] both ephedrine and pseudoephedrine have been declared prohibited substances by the wada.[14] sibutramine dietary supplements adulterated with sibutramine, an anti-obesity agent, which do not mention the presence of this compound on the packaging label, have also appeared on the market. sibutramine has been found in products advertised as ‘pure herbal’ slimming capsules and ‘natural’ tea.[22-24] urinary metabolites of sibutramine were found in detectable quantities 50 hours after administration of a single ‘dose’ of tea to a volunteer.[24] this synthetic anorectic drug, which only has market approval as a prescription anti-obesity agent, has been on the wada prohibited list since 2006. furthermore, market withdrawal of sibutramine was recommended by the european medicines agency at the beginning of 2010. this agent produces severe systemic adverse effects, blood pressure elevation and cardiac effects (tachycardia), and patients using sibutramine are required to be monitored by a physician experienced in the treatment of obesity and familiar with this agent, on a regular basis. methylhexaneamine methylhexaneamine, a stimulant originally intended to be marketed as a nasal decongestant, has been detected as an ingredient of dietary supplements and was declared a prohibited compound by the wada in 2009.[25] the serious adverse effects of this stimulant have recently been highlighted by a case report on the death of two us soldiers who were taking commercially available dietary supplements that contained methylhexaneamine. both soldiers collapsed from cardiac arrest during physical exertion and ultimately died.[26] the issues surrounding this stimulant have been complicated by the fact that methylhexaneamine is found on package labels under a very wide variety of chemical and non-chemical names, e.g. 1,3-dimethylamylamine, 1,3-dimethylpentylamine, 2-amino-4-methylhexane, 2-hexanamine, 4-methyl-2-hexanamine, 4-methyl-2-hexylamine, 4-methylhexan-2-amine, dimethylamyl amine, methyl hexaneamine, dimethylpentylamine, floradrene, forthan, forthane, fouramin, geranamine, geranium extract, geranium flower sajsm vol. 26 no. 2 2014 61 extract, geranium oil, geranium stems and leaves, metexaminum, methexaminum, etc. only the names methylhexaneamine and dimethy lpentylamine appear on the wada 2011 list of prohibited agents, creating even further confusion among consumers and complicating identification. while geranium root extract or geranium oil are mentioned as natural sources of methylhexaneamine, the presence of this compound in these plant products could not be demonstrated on analysis, strengthening the suspicion that it was added during or after the manufacturing process.[27] conclusion while food supplements and pharmaceutical agents may enhance strength and performance of athletes, there is insufficient scientific data to support this theory. although stimulants have been widely used among athletes for performance enhancement, these substances are prohibited by the wada. in addition, ingestion of stimulants via accidentally or intentionally contaminated dietary supplements may lead to failed doping tests and its consequences. the presence of stimulants in nutritional supplements may also lead to serious systemic adverse effects; athletes, coaches and sports doctors should be aware of these pitfalls when using or advising on the intake of these products. the risk of accidental ingestion of forbidden substances from dietary supplements can be diminished by using ‘safe’ products listed on databases such as those available in the netherlands and germany.[12] references 1. zadik z, nemet d, eliakim a. hormonal and metabolic effects of nutrition in athletes. j pediatr endocrinol metab 2009;22(9):769-777. [http://dx.doi.org/10.1515/ jpem.2009.22.9.769] 2. jenkinson dm, harbert aj. supplements and sports. am fam physician 2008;78(9):1039-1046. 3. bishop d. dietary supplements and team-sport performance. sports medicine 2010;40(12):995-1017. [http://dx.doi.org/10.2165/11536870-000000000-00000] 4. geyer h, braun h, burke lm, stear sj, castell lm. a-z of dietary supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance – part 22. br j sports med 2011;45(9):752-754. [http://dx.doi.org/10.1136/ bjsports-2011-090180] 5. transparency market research. nutraceuticals product market is expected to reach usd 204.8 billion globally in 2017. www.transparencymarketresearch.com/globalnutraceuticals-product-market.html (accessed on 15 july 2013). 6. food and drug administration. what is a dietary supplement? www.fda.gov/food/ dietarysupplements/qadietarysupplements/default.htm [accessed on 15 may 2014]. 7. sundgot-borgen j, berglund b, torstveit km. dietary supplements in norwegian elite athletes – impact of international ranking and advisors. scand j med sci sports 2003;13(2):138-144. [http://dx.doi.org/10.1034/j.1600-0838.2003.10288.x] 8. sobal j, marquart lf. vitamin/mineral supplement use among athletes: a review of the literature. int j sport nutr 1994;4(4):320. 9. erdman ka, fung ts, reimer ra. influence of performance level on dietary supplementation in elite canadian athletes. med sci sports exerc 2006;38(2):349356. [http://dx.doi.org/10.1249/01.mss.0000187332.92169.e0] 10. maughan rj, depiesse f, geyer h. the use of dietary supplements by athletes. j sports sci 2007;25(suppl 1):s103-113. [http://dx.doi.org/10.1080/02640410701607395] 11. striegel h, simon p, wurster c, niess am, ulrich r. the use of dietary supplements among master athletes. int j sports med 2006;27(3):236-241. [http://dx.doi. org/10.1055/s-2005-865648] 12. geyer h, parr mk, koehler k, mareck u, schänzer w, thevis m. nutritional supplements cross-contaminated and faked with doping substances. j mass spectrom 2008;43(7):892-902. [http://dx.doi.org/10.1002/jms.1452] 13. harel z, harel s, wald r, mamdani m, bell cm. the frequency and characteristics of dietary supplement recalls in the united states. jama intern med 2013;173(10):926928. [http://dx.doi.org/10.1001/jamainternmed.2013.379] 14. world anti doping agency. the 2013 prohibited list. http://www.wada-ama.org/en/ world-anti-doping-program/sports-and-anti-doping-organizations/internationalstandards/prohibited-list/ (accessed on 15 may 2014). 15. bell dg, mclellan tm, sabiston cm. effect of ingesting caffeine and ephedrine on 10 km run performance. med sci sports exerc 2002;34(2):344-349. 16. bell dg, jacobs i, ellerington k. effect of caffeine and ephedrine ingestion on anaerobic exercise performance. med sci sports exerc 2001;33(8):1399-1403. [http:// dx.doi.org/10.1097/00005768-200108000-00024] 17. shekelle pg, hardy ml, morton sc, et al. efficacy and safety of ephedra and ephedrine for weight loss and athletic performance: a meta-analysis. jama 2003;289(12):15371545. [http://dx.doi.org/10.1001/jama.289.12.1537] 18. chu ks, doherty tj, parise g, milheiro js, tarnopolsky ma. a moderate dose of pseudoephedrine does not alter muscle contraction strength or anaerobic power. clin j sport med 2002;12(6):387-390. 19. gillies h, derman we, noakes td, smith p, evans a, gabriels g. pseudoephedrine is without ergogenic effects during prolonged exercise. j appl physio 1996;81(6):2611-2617. 20. hodges k, hancock s, currell k, hamilton b, jeukendrup ae. pseudoephedrine enhances performance in 1 500 m runners. med sci sports exerc 2006;38(2):329333. [http://dx.doi.org/10.1249/01.mss.0000183201.79330.9c] 21. national institutes of health. pseudoephedrine: what side effects can this medication cause? www.nlm.nih.gov/medlineplus/druginfo/meds/a682619.html (accessed on 15 may 2014). 22. jung j, hermanns-clausen m, weinmann w. anorectic sibutramine detected in a chinese herbal drug for weight loss. forensic sci int 2006;161(2-3):221-222. [htt[:// dx.doi.org/10.1016/j.forsciint.2006.02.052] 23. vidal c, quandte s. identification of a sibutramine-metabolite in patient urine after intake of a ‘‘pure herbal’’ chinese slimming product. ther drug monit 2006;28(5):690692. [http://dx.doi.org/10.1097/01.ftd.0000245392.33305.b0] 24. koehler k, geyer h, guddat s, et al. sibutramine found in chinese herbal slimming tea and capsules. in: schänzer w, geyer h, gotzmann a, mareck u, eds. recent advances in doping analysis. cologne: sportverlag strauß, 2007:367. 25. thevis m, sigmund g, geyer h, schänzer w. stimulants and doping in sport. endocrinol metab clin north am 2010;39(1):89-105,ix. [http://dx. doi.org/10.1016/j.ecl.2009.10.011] 26. eliason mj, eichner a, cancio a, bestervelt l, adams bd, deuster pa. case reports: death of active duty soldiers following ingestion of dietary supplements containing 1,3-dimethylamylamine (dmaa). mil med 2012;177(12):1455-1459. 27. lisi a, hasick n, kazlauskas r, et al. studies of new stimulants. lecture held at the 29th cologne workshop on dope analysis, 15 february 2011, cologne, germany. http://dx.doi.org/10.1515/jpem.2009.22.9.769] http://dx.doi.org/10.1515/jpem.2009.22.9.769] http://dx.doi.org/10.2165/11536870-000000000-00000] http://dx.doi.org/10.1136/bjsports-2011-090180] http://dx.doi.org/10.1136/bjsports-2011-090180] http://www.transparencymarketresearch.com/global-nutraceuticals-product-market.html http://www.transparencymarketresearch.com/global-nutraceuticals-product-market.html http://www.transparencymarketresearch.com/global-nutraceuticals-product-market.html http://www.fda.gov/food/ http://dx.doi.org/10.1034/j.1600-0838.2003.10288.x] http://dx.doi.org/10.1249/01.mss.0000187332.92169.e0] http://dx.doi.org/10.1080/02640410701607395] http://dx.doi.org/10.1055/s-2005-865648] http://dx.doi.org/10.1055/s-2005-865648] http://dx.doi.org/10.1002/jms.1452] http://dx.doi.org/10.1001/jamainternmed.2013.379] http://www.wada-ama.org/en/ http://dx.doi.org/10.1097/00005768-200108000-00024] http://dx.doi.org/10.1097/00005768-200108000-00024] http://dx.doi.org/10.1001/jama.289.12.1537] http://dx.doi.org/10.1249/01.mss.0000183201.79330.9c] http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682619.html http://dx.doi.org/10.1097/01.ftd.0000245392.33305.b0] http://dx.doi.org/10.1016/j.ecl.2009.10.011] introduction soccer is one of the most popular sports in the world, and has been played in many countries of the world, including south africa, for more than 100 years.1 currently there are 208 member associations of fifa.1 the popularity of soccer in south africa is seen in the township streets, where it is commonly played by boys. however, more recently girls can also be seen playing soccer in the streets. although there has been organised soccer for young players over a decade, with leagues being played annually, the emphasis has mainly been on male players. as the number of females participating in sports has increased, so has the necessity to understand the effect of female growth and development on participation, athletic ability and injury patterns.2-4 however, there are limited data on female soccer players, as most studies on soccer concentrate on male soccer players.5-7 although participation in youth soccer for girls has started to increase in the past few years in south africa, no studies have been published to determine the profile of injuries in adolescent girls. because of the limited information on injuries in female soccer players, it cannot be stated whether or not characteristics and causes of injuries are similar or vary substantially from those previously reported for male players.6 as a contribution to learning more about injuries associated with female soccer players, this study was conducted to establish the prevalence and injury profile of lower extremity injuries in female high school soccer players. methodology this study was conducted using a retrospective descriptive questionnaire-based design. out of 42 high schools from johannesburg east district recruited to participate, only 13 schools had female soccer teams. data were collected during the schools’ soccer season from may to august 2006. this included information from the 2005 season. permission to conduct the study was granted by the human research ethics committee from the university of the witwatersrand, gauteng department of education and schools that participated in the study. informed consent and assent was signed by parents/guardians and participants before the questionnaires were administered. the questionnaire was developed and piloted for validity; it included point and 1-year prevalence, profile of injuries, 8 player position, age, use of equipment, frequency of play, and training duration. the questionnaires were distributed by the researcher during training sessions and collected again immediately after the training session. original research article common lower extremity injuries in female high school soccer players in johannesburg east district abstract objectives. soccer is one of the sports in south africa which has seen an increase in the participation of youth and adult female players. the aim of this study was to determine point and 1-year prevalence, profile of injuries that affect female soccer players, associations between injuries and player position, age, use of equipment, frequency of play, and training duration. methods. a retrospective questionnaire-based descriptive survey of 103 first team high school female soccer players in the johannesburg east district was conducted. results. the 1-year prevalence for the participants who reported injuries was 46% (n=47) and the point prevalence was 33% (n=34). from these, a total of 78 and 42 injuries for the 1-year and point prevalence respectively were reported. an extended duration of skills (p=0.0001) and fitness (p=0.02) training in this population reduced the likelihood of incurring an injury. the older the participants, the more chance there was of sustaining injuries (p=0.01). the participants who wore shin guards were less prone to shin/leg injuries (p=0.01), the relative odds being 0.35. the midfielders had more foot and toe injuries than the other players (p=0.05). starting age (p=0.78), frequency of play (p=0.83), wearing of shoes (p=0.54) and stretching had no influence on injury. the knee and ankle were the main locations of injury, with defenders and midfielders mostly being injured. conclusion. a decrease in the duration of training for both skills and fitness and not wearing shin guards are risk factors for injury in female soccer players in high school. the profile of injuries and the risk factors determined from this study do not differ from the studies done in male adolescent and adult soccer players. correspondence: ms siphe mtshali department of physiotherapy university of the witwatersrand 7 york road parktown, 2193 tel: 27 11 717 3702 fax: 27 86 553 4766 e-mail:siphe.mtshali@wits.ac.za primrose ts mtshali (msc physio) 1 nonceba p mbambo-kekana (phd) 1 aimee v stewart (phd) 1 eustacius musenge (msc med bio+epi) 2 1 department of physiotherapy, university of the witwatersrand, johannesburg 2 school of public heath, agincourt health and population unit, university of the witwatersrand, johannesburg sajsm vol 21 no. 4 2009 163 several statistical procedures were used in the analysis, namely fischer’s exact test, student t-test and logistic regression. to find associations between pairs of categorical variables fischer’s exact test was used. the student’s t-test was used to test for differences between two groups of gaussian numerical variables. univariate as well as multivariate regressions were done using a logistic regression. these calculations were done to find association between the factors (age, location of injuries, and frequency of play, training duration, stretching and use of soccer boots and shin guards (equipment) with the dichotomous response variable. statistical significance was accepted at the 5% level of significance. results demographic data nine schools participated in the study as the other four schools that offered girls’ soccer were not currently active in soccer during the study. the schools had 11 players and 4 reserve players (n=135) in the first team and those with signed consent were given questionnaires (n=103). the sample size of 103 represents 76% of the total sample. the average age of the participants was 16.1±1.4 years and they started playing soccer when they were 12.1±2.7 years old. the distribution of player position was as follows: goalkeeper (8%), defenders (41%), midfielder (33%) and strikers (18%). the equipment used by the players is illustrated in table i. in this study, the participants (77%) played one match per week whereas the training was mainly twice a week. during training 91% of the participants did skills training and 96% did fitness training. the duration of training was on average 45 60 minutes. injuries the operational definition for injury used in this study was, as defined by fuller et al.,8 as ‘any physical complaint sustained by a player that results from a football match or football training, irrespective of the need for medical attention or time-loss from football activities’. prevalence is the measure of injuries in a population at a given point in time (point prevalence) and can also be measured over a period of time (period prevalence).9 the 1-year (2005) prevalence of participants injured was 46% (n=47) and the point (2006) prevalence of participants injured was 33% (n=34). location of injuries seventy-eight injuries were reported for 1-year prevalence and point prevalence reported 42 injuries. the participants reported more than one injury. of all the reported injuries the knee and ankle were the most injured areas (table ii). associations of injuries of various factors and injury association between age and injury for the point prevalence, current age was associated with injury (p=0.01), meaning that the older the player the more likely they were to be injured. there was no association between the age of starting to play soccer and injury for point prevalence. 164 sajsm vol 21 no. 4 2009 table i. use of equipment equipment n=103 % shoes shoes with studs 83 81 shoes without studs 18 18 bare feet 2 2 shin guards 54 52 (n is the total number players.) table iii. association between duration of training and injury for point prevalence duration of training skill fitness (minutes) n=32 n=33 30 0 0 45 19 59 6 18 60 8 25 5 15 90 5 16 22 67 p-value 0.0001 0.02 (n is the number of participants involved skills/fitness training.) table ii. frequency distribution of location of injuries location of injuries one-year point prevalence prevalence (2005) (2006) n=78 % n=42 % hip joint 5 6 0 groin muscle 2 3 0 quadriceps muscle 5 6 0 hamstrings muscle 5 6 0 knee joint 19 24 12 29 leg bone 7 9 7 17 calf muscle 7 9 0 ankle joint 18 23 17 41 foot and toes 10 13 6 14 (n is number of injuries.) table iv. association between location of injuries and player position (point prevalence) point prevalence goalkeeper defender midfielder striker p-value n % n % n % n % knee joint 1 8 6 60 2 17 3 25 0.28 leg bone 1 14 3 43 2 29 1 14 0.29 ankle joint 0 8 47 6 36 3 18 0.36 foot and toes 0 1 17 4 67 1 17 0.05 (n is the number players that reported injuries according to the position played.) association between duration of training and injury more injuries were reported as the duration of skills training increased (for 1-year prevalence), but this was not a significant association (p=0.06). the point prevalence of injuries was highest when players did skills training for 45 minutes (p=0.0001) and fitness training for 90 minutes (p=0.02). players who trained for 30 minutes or less did not report any injuries (table iii). association between location of injuries and player position there was no association between player position and location of injury for the 1-year prevalence; however there was an association in point prevalence results where the midfielders had 67% toe and foot injuries and were most likely to incur foot and toe injuries (p=0.05) compared with other positions (table iv). extrinsic risk factors associated with injuries tables v and vi summarise the risk factors associated with injury for point and 1-year prevalence. the odds ratios (or) in the tables illustrate the protectiveness of the different variables against injury. the results (table v) show that shin guards were associated with a reduced the risk of having an injury (or=0.35) (p=0.01). the age of the players was associated with injury, with older players having a greater chance of being injured (or=0.64) (p=0.01). the duration of fitness training reduced the risk of injury if fitness training was more than 45 minutes (or=0.51) (p=0.02) (table vi). discussion although studies 5-7,10-12 have been done mainly in male adolescent soccer players, the results are similar to the results of this study. this study reports the number of injuries as being between 38% and 46%. this is however lower than the rate of injury in the adult professional female soccer players, which ranges from 55% to 70%.13,14 the difference between adolescent and adult female studies may be attributable to the level of exposure, where the professional players have an increased number of training sessions per 1 000 hours and up to two matches per week which are of a longer duration (90 minutes). in this study, training and matches were played mainly once a week and the duration of matches was 60 minutes. sajsm vol 21 no. 4 2009 165 table v. extrinsic risk factors associated with injuries (1-year prevalence) variable one-year prevalence odds ratio standard error 95% confidence level p-value starting age 0.98 0.92 0.85 1.13 0.78 current age 0.88 2.28 0.67 1.16 0.37 training skill 0.64 0.7 0.16 2.55 0.53 fitness 0.26 0.17 0.03 2.64 0.26 duration of training skill 1.03 0.18 0.72 1.47 0.86 fitness 1.24 0.18 0.86 1.77 0.25 matches per week 0.94 0.29 0.53 1.6 0.83 player position 0.75 0.23 0.48 1.18 0.2 shoes 1.36 0.5 0.50 3.68 0.54 shin guards 0.35 0.41 0.16 0.79 0.01 table vi. extrinsic risk factors associated with injury (point prevalence) variable point prevalence odds ratio standard error 95% confidence level p-value starting age 1.04 0.07 0.9 1.21 0.6 current age 0.64 0.19 0.4 0.9 0.01 training skill 3.14 1.12 0.35 28.1 0.31 fitness 1000 546 0.001 1000 1 duration of training skill 1.06 0.21 0.7 1.6 0.8 fitness 0.51 0.3 0.3 0.9 0.02 matches per week 0.83 0.38 0.4 1.7 0.62 player position 0.9 0.24 0.55 1.45 0.65 shoes 0.9 0.52 0.32 2.45 0.82 shin guards 0.82 0.44 0.35 1.94 0.65 the presence of more knee and ankle injuries may be attributed to the skill of cutting, jumping and landing, which is different in girls. when comparing adolescent females and males during unanticipated cutting manoeuvres, females had a greater abduction of the knee; this in turn increases the genu valgus, which may be a risk factor for knee injuries, specifically the anterior cruciate ligament.15 the ankle is the main point of contact during soccer matches and training, therefore it is most likely to incur more injuries. the higher number of knee and ankle injuries in this study is consistent with a number of prospective studies where the knee was the most commonly injured area followed by ankle injuries in a female population.4,12,14,17 the exposure level in this study also contributed to the higher rate of minor injuries which were reported. other studies on high school soccer players11,12 also report that there are more minor injuries associated with exposure level. foul play may contribute to incidence of severe injuries because of poor application of the rules of the game and poor refereeing. in addition, severe injuries may occur as a result of poor pitch surfaces.2 no injuries were reported for the shorter (30 minutes or less) duration of skills and fitness training in this study and most injuries occurred after skills training for 45 minutes. thereafter there was a downward trend in the number of injuries as the duration of skills training increased (table iii). although there was statistical significance in the duration of fitness training (p=0.02) and injury, it was difficult to determine the mechanism of injury. it may be speculated that as skill and fitness improves so does the confidence of players in handling opponents during matches. the decrease in the number of injuries as the duration of skills training increases in this study is in contrast with the study on male players,10 where there was an increase in the number of injuries in players with low skill level. the defenders (41%) and midfielders (33%) were the players most commonly injured in this study. this can be understood because soccer is more robust in midfield and strength of the lower limbs is required to win the ball. the defenders put their lower extremities ‘on the line’ when defending a ball, hence they are most likely to be injured. the midfielders were found to be more likely to incur foot and toe injuries (p=0.05) compared with other positions. tackling and running during matches for players in the midfield positions could be associated with injuries. although other studies report that defenders and midfielders are injured more in relation to other positions of play,7,10,19 the location of injuries was not related to player position. in this study there was a small number of leg or shin injuries (9%) for 1-year prevalence (table ii), but the results show that wearing shin guards (table v) reduces the risk of shin injuries (p=0.01). the likelihood of reducing an injury by wearing skin guards in this study (table v) was 65% (or=0.35). contact with another player may be the cause of acute shin injuries rather than overuse injuries. lilley et al.18 reported ankle injuries to be 24% followed by shin injuries at 18% as being the highest percentage of injuries in their retrospective study of an adolescent soccer population, but it was not clear whether the participants were wearing shin guards or not. therefore it is not possible to compare the two studies. however, not wearing shin guards has been shown to have a direct link to leg injuries.10 in conclusion the results of this study show that injuries occur mainly to the knee and ankle, but factors contributing to the injuries need to be investigated further. the 1-year and point prevalence data in this study were within the ranges reported in other similar studies. this study showed an association between various risk factors (shin guards, current age, and duration of fitness training) and injury. however, these results need to be viewed with caution because of the small sample size. the practical applications of these data are that training on proper skills and fitness programmes for school coaches or educators should be implemented to reduce the number of injuries. furthermore, it may be recommended that shin guards should be worn to reduce the risk of leg injuries. references 1. www.fifa.com (accessed 12 may 2009). 2. goga ie, gongal p. severe soccer injuries in amateurs. br j sports med 2003;37:498-501. 3. hewett te. neuromuscular and hormonal factors associated with knee injuries in female athletes: strategies and prevention. sports med 2000;29(5):313-327. 4. odion aa. injury pattern of the national female soccer team of nigeria (the falcons) from 1997-1999. journal of the nigerian medical rehabilitation therapists 2001;6(1):11-16. 5. hutchinson mr, nasser r. common sports injuries in children and adolescents. medscape general medicine 2000; 2(4): (http://www.medscape. com/viewarticle/408524) 6. junge a, dvorak j. soccer injuries: a review on incidence and prevention. sports med 2004;34(13):929-938. 7. kucera kl, marshall sw, kirkendall, marchak pm, garrett jr we. injury history as a risk factor for incident injury in youth soccer. brit j sports med 2005;39:462-466. 8. fuller cw, ekstrand j, junge a, et al. consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries. clin j sport med 2006;16(2):97-106. 9. friis r, sellers t. epidemiology for public health practice. second edition. gaithersburg, maryland: aspen publish, inc., 1999. 10. dvorak j, junge a. football injuries and physical symptoms: review of literature. am j sports med 2000;28(5):s3-s9. 11. le gall f, carling c, reilly t, vandewalle h, church j, rochcongar p. incidence of injuries in elite french youth soccer players: a ten-season study. am j sports med 2006;34(10):1-11. 12. powell jw, barber-foss kd. sex related patterns among selected high school sports. am j sports med 2000;28(3):385-391. 13. faude o, junge a, kinderman w, dvorak j 2005 injuries in female soccer players: a prospective study in the german national league. am j sports med 2005;33(11):1694-1700. 14. giza e, mithofer k, farrell l zarins b, gill t. injuries in women’s professional soccer. br j sports med 2005;39:212-216. 15. ford kr, meyer gd, toms he, hewett te. gender specific differences in the kinematics of unanticipated cutting in young athletes. med sci sports exerc 2005;37(1):124-129. 16. emery ca, meeuwisse wh, hartmann se. evaluation of risk factors for injury in adolescent soccer: implementation and validation of an injury surveillance system. am j sports med 2005;33(12):1882-1891. 17. emery ca, meeuwisse wh. risk factors for injury in indoor compared with outdoor adolescent soccer. am j sports med 2006;34(10):1636-1644. 18. lilley k, gass e, locke s. a retrospective injury analysis of state representative female soccer player. phys ther 2002;3:2-9. 19. van heerden hj. the evaluation of injury in junior soccer players. s afr j sports med 1992;7(2):3-6. 166 sajsm vol 21 no. 4 2009 sajsm editorial.indd 94 sajsm vol. 25 no. 4 2013 editorial �e ethics of publishing a recent incident i encountered as editor of this journal drew my attention to the risk that we face as a result of unethical practices in science. it takes an incident like this to heighten awareness about how vulnerable the ‘scienti�c process’ is to abuse. �e scienti�c process is based on principles of trust and honesty. �is starts at the datacollection phase of the experiment and includes the data analysis, writing phase (i.e. using own original text) and the avoidance of ‘cherry picking’ published work to support one’s own data. before the manuscript is published, it has to go through a process of peer review – although this is touted as the core of the scienti�c process, it may also have irregularities when a reviewer, for example, blocks studies which have a counter view to the reviewer’s own paradigm. my �rst exposure to ‘science gone bad’ was when i was a student and went to visit a friend working at the university of vermont college of medicine, usa. she introduced me to a prominent scientist at the time, eric poelhman, who was well published in the area of obesity, physical activity, ageing and menopause. as a relatively young scientist, poelhman had nearly 200 publications. i followed his career with interest and was staggered when i found out that he had been charged with conducting fraudulent work.[1] �e charges included falsifying data in a well-cited paper published in the annals of internal medicine in 1995. this study showed that hormone-replacement therapy could prevent the decline in energy expenditure and increases in body fat during menopause. �e study included data on 35 women, many of whom did not exist.[1] a�er a long investigation, poelhman pleaded guilty to fabricating data in 10 of his papers that were submitted between 1992 and 2000. he also pleaded guilty to falsifying 17 grant applications to the national institutes of health.[2] his punishment: 1 year in jail and he was barred from getting more federal research grants. he was also ordered by the court to write letters of retraction and correction to several scienti�c journals.[2] how many more cases are there like this, but where the scientists have not been caught? how much money has been wasted on sponsoring fraudulent research? how much harm has fraudulent research caused? i’m sure if we knew the answers to these questions we would be alarmed. in an attempt to promote principles of best practice for publishing scienti�c papers, the international journal of cardiology published the following set of guidelines. �ese provide an excellent summary and are worth repeating and applying to papers submitted to the south african journal of sports medicine:[3] ‘1. �at the corresponding author has the approval of all other listed authors for the submission and publication of all versions of the manuscript. 2. �at all people who have a right to be recognised as authors have been included on the list of authors and everyone listed as an author has made an independent material contribution to the manuscript. 3. that the work submitted in the manuscript is original and has not been published elsewhere and is not presently under consideration of publication by any other journal. �e oral or poster presentation of parts of the work and its publishing as a single page abstract does not count as prior publication for this purpose. 4. �at the material in the manuscript has been acquired according to modern ethical standards and does not contain material copied from anyone else without their written permission. 5. �at all material which derives from prior work, including from the same authors, is properly attributed to the prior publication by proper citation. 6. �at the manuscript will be maintained on the servers of the journal and held to be a valid publication by the journal only as long as all statements in these principles remain true. 7. �at if any of the statements above ceases to be true the authors have a duty to notify the journal as soon as possible so that the manuscript can be withdrawn.’ to �nish up, as the year draws to a close i would like to thank everyone that i have asked to review papers. �is is a time-consuming task for which there is no apparent recognition. the growth of the journal can be attributed to their thoroughness and dedication. �e acceptance rate of papers submitted to the south african journal of sports medicine for review hovers around 60%, and there is a waiting list of accepted papers. �ese are all positive signs that bode well for the future! mike lambert editor-in-chief references 1. kintish e. researcher faces prison for fraud in nih grant applications and papers. science 2005;307(5717):1851. [http://dx.doi.org/10.1126/science.307.5717.1851a] 2. http://www.wikipedia.org/wiki/eric_poehlman (accessed 20 november 2013). 3. coates ajs. ethical authorship and publis. int j cardiology 2009;131(2):149-150. s afr j sm 2013;25(4):94. doi:10.7196/sajsm.524 introduction athletes and sports dietitians have sought post-exercise nutritional strategies that will enhance muscle glycogen resynthesis after exercise, enhance recovery and maintain or improve the quality of future workouts or performances. 1-3 athletes may participate in one or more training sessions a day with anywhere from 6 to 24 hours of recovery between workouts. 3 a principal component of training for an elite athlete is to maximise training in order to increase potential for competition. because full and often rapid recovery is necessary for optimal performance, 2 athletes should practise nutritional strategies that maximise recovery. dietary recommendations for pre-competition nutritional strategies have been well established. 1 because muscle glycogen is the main fuel during intense exercise, replenishing muscle glycogen stores in the post-exercise recovery period is an important factor influencing recovery and performance. in addition, the timing and composition of a post-exercise meal is highly dependent upon the duration and intensity of the preceding exercise bout. 4 research regarding postexercise nutritional strategies has focused on timing of ingestion, type of cho (solid v. liquid), amount of carbohydrate, presence of other nutrients (e.g. protein), and frequency of post-exercise feedings to determine the most effective way to enhance glycogen resynthesis. 5 research examining carbohydrate consumption during recovery periods of 4 hours or more suggests enhanced recovery and exercise performance which would be beneficial to athletes competing in events with short recovery periods (preliminary heats, finals) such as track and field, swimming, and multiple day events, such as the tour de france. guidelines regarding the optimal timing and amount of carbohydrate after exercise have been well established. 3,4 this article will provide an overview and discussion of the research that focuses on the effects of cho and cho:pro feedings after exercise on various indices of recovery, including muscle damage, glycogen resynthesis and exercise performance. research has also examined the effectiveness of the addition of protein to a post-exercise carbohydrate beverage on recovery. in addition, this paper will review the existing guidelines for a post-exercise recovery meal, 4 including timing and presence of other nutrients. carbohydrate and recovery muscle glycogen is the primary fuel source during high-intensity exercise and an important source during endurance exercise. therefore, after prolonged intense exercise, post-exercise glycogen restoration plays a very important role in the recovery process. because endogenous carbohydrate is a crucial but relatively limited fuel during high-intensity prolonged endurance exercise, it must be replenished. post-exercise glycogen synthesis is highly dependent on the extent of glycogen depletion, as well as the type, duration and intensity of the exercise session. 6 for up to 6 hours after exercise, the rate of muscle glycogen resynthesis is accelerated, and within 24 hours after exercise complete restoration of glycogen stores can occur when sufficient amounts of carbohydrate are consumed. 1,7 glycogen resynthesis after a glycogen-depleting exercise bout or endurance exercise occurs in two phases. the first phase, or the rapid phase, review nutritional strategies for post-exercise recovery: a review abstract finding the optimal nutrition regimen for enhanced recovery is fundamental in enhancing exercise training and performance. therefore, research has aimed to examine post-exercise nutritional strategies for optimal recovery. because muscle glycogen is the primary substrate utilised during high-intensity exercise, it must be replenished. recent research has examined the effectiveness on recovery of adding protein to a post-exercise carbohydrate beverage. this review summarises and analyses the literature on nutritional strategies aimed at enhancing various indicators of post-exercise recovery: glycogen resynthesis, muscle damage and performance. furthermore, the literature on medline and pubmed comparing the effectiveness of carbohydrate-only (cho) beverage with a carbohydrate:protein (cho:pro) beverage on maximising recovery was reviewed. the methods and results of studies regarding post-exercise nutritional strategies for recovery were analysed. primary results of this review suggest that the optimal timing in regard to post-exercise nutritional strategies for maximal glycogen resynthesis is within the first 30 minutes after exercise. the literature suggests that 1.0 1.5 g.kg -1 h -1 of carbohydrate ingested at 2-hour intervals after exercise for up to 6 hours may be optimal for recovery. the addition of protein to a post-exercise meal may supply additional amino acids necessary for muscle repair creating an anabolic condition. correspondence: kelly pritchett department of health, human performance and nutrition 400 east university way central washington university ellensburg, wa 98926 tel: 205-887-1809 e-mail: kkerr@cwu.edu kelly l pritchett (phd, rd, cssd) 1 robert c pritchett (phd) 1 philip bishop (edd) 2 1 department of health, human performance, and nutrition, central washington university, ellensburg, wa 2 kinesiology department, university of alabama, tuscaloosa, al 20 sajsm vol 23 no. 1 2011 sajsm vol 23 no. 1 2011 21 lasts anywhere from 30 to 60 minutes and is insulin independent due to the increased permeability of the muscle cell as a result of exercise-induced translocation of glut-4 (glucose transporter carrier protein-4) and plausibly an up-regulation of glycogen synthase. an increase in post-exercise glycogen synthase and exercise-induced increases in insulin sensitivity may be the potential mechanism res ponsible for the 2to 4-hour period of enhanced glycogen resynthesis following exercise. the literature indicates that a recovery meal consumed within 2 hours after exercise, compared with no feeding, is effective in improving recovery. 8 because complete muscle glycogen resynthesis can take as long as 24 hours, even under optimal conditions, studies have examined methods to increase the rate of muscle glycogen resynthesis. 9 depending on the extent of glycogen depletion, consuming 1.0 1.5 g cho.kg -1 h -1 immediately after exercise, and at 30-minute intervals for up to 6 hours after exercise, appears to be optimal for adequate glycogen resynthesis. 1,4,10,11,25 on the other hand, if cho intake is delayed by 2 hours, glycogen resynthesis rates have been found to be 45% lower. 3,12 intestinal absorption of glucose is possibly a rate-limiting factor for glycogen resynthesis when a large bolus of carbohydrate is consumed after exercise. 13 cho supplementation (~1.0 g.kg -1 h -1 ) provided at frequent intervals (15 60-minute intervals) after exercise has been suggested to be more effective than a large bolus in maintaining higher blood glucose levels, thereby resulting in increased muscle glycogen restoration. 1,3 the majority of the research has examined the effect of a postexercise recovery beverage given in 1-hour increments. however, little research has examined the effects of providing a post-exercise beverage at more frequent intervals versus a large bolus feeding. research regarding glycogen resynthesis rates is equivocal when different amounts of carbohydrate were consumed after exercise. 1,6 ingesting a carbohydrate beverage at more frequent intervals (30-minute intervals) has been associated with enhanced glycogen resynthesis rates. 1,12,14 van loon et al. found that an increase in post-exercise consumption of carbohydrate from 0.8 to 1.2 g.kg -1 h -1 taken at 30-minute intervals increased muscle glycogen synthesis rates (16.6 v. 35.4 mmol.kg -1 . dw.h -1 ) in 8 trained cyclists following a glycogen depletion cycling trial. 6 the majority of studies that have found no effect on glycogen resynthesis with increased carbohydrate intake post exercise have supplemented at 2-hour intervals. 12,14 recent research suggests that 2-hour intervals may not be optimal for increasing muscle glycogen resynthesis, especially since rapid resynthesis occurs within the first 2 hours after exercise. 6,15-17 other studies have reported higher glycogen resynthesis rates when a supplement was ingested more frequently as opposed to one large bolus. 10,18 the research shows positive results for a post-exercise bolus feeding on glycogen resynthesis, recovery and performance. however, further research is needed to determine whether a postexercise feeding provided at more frequent time intervals during the recovery period could result in further improved performance. discrepancies among study results may be due to the difference in table i. summary of studies that investigated the effectiveness of a cho-only beverage versus a cho:pro beverage on recovery and performance indices grouped according to year published author (year) subjects (n) protocol measures treatment results carrithers, 2000 7 male collegiate cyclists 70% max to exhaustion, overnight rest, 75 m @70% max to exhaustion & 6 x 1 m sprints muscle glycogen serum glu serum insulin cho, cho:pro, cho:aa eucaloric (1 g.kg -1 cho), every 30 m for 4 h no diff. in muscle glycogen or performance ivy, 2002 7 trained male cyclists 2.5 h @ 70% max cycl., tx @ 1, 2 h postexercise muscle gly plasma insulin cho: pro (80:28) lcho (80 g) h cho (108 g) cho:pro sig. (p<0.05) higher gly resynth saunders, 2004 15 trained male cyclists 75% max to exhaustion 12-15 h recovery 85% max to exhaustion cpk performance cho (7.3%) & cho:pro (7.3%: 1.8%) given during and post exercise 83% lower cpk in cho:pro, 40% longer tt (cho:pro) betts, 2005 9 (study a) 7 (study b) recreational athletes 90 min run @ 70% max to exhaustion, 4 h recovery run time to exhaustion @ 85% max insulin response 9% cho v. 9% cho: 1.5% pro (1.2 g.kg -1 .h -1 cho v. 0.8 g.kg -1 .h -1 ) no diff. in performance, sig. (p<0.05) greater insulin response w cho:pro karp, 2006 9 trained male cyclists interval workout 4 h recovery 70% max to exhaustion cycling performance total work rpe choc milk, fr (gatorade), cr (endurox): (1 g.kg -1 .h -1 cho) for first 2 h post exercise tt & total work were sig. (p<0.05) greater w fr and choc milk berardi, 2006 6 competitive male cyclists 60 min time trial (am) 6 h recovery 60 min time trial (pm) muscle glycogen time trial performance isocaloric (4.8 kcal.kg-1) cho: pro (0.8 g.kg -1 , 0.4 g.kg -1 ), cho (1.2 g.kg -1 ), plb for 2 h post exercise, followed by solid meal 4 h post (7 kcal.kg -1 ) liquid cho:pro (p<0.05) greater gly synthesis during recovery no diff tt luden, 2007 23 cross-country runners (11m, 12 f) 6 d suppl. during workout cpk 5k & 8k soreness cho:pro:a (1.4 g.kg -1 cho, 0.3 g.kg -1 pro, vit c & e), cho (1.46 g.kg -1 ): 30 min post exercise sig. (p<0.05) lower cpk, & soreness in c:p:a. no diff. in performance tt = time trial, cpk = creatine kinase, cho = carbohydrate, pro = protein, c:p:a = carbohydrate, protein, antioxidant, plb = placebo. protocols used, timing and interval of post-exercise recovery meals, training status of subjects, and form of cho. therefore, considering these limitations and inconsistency among the research protocols, current research suggests that 1.0 1.5 g.kg -1 h -1 of cho is sufficient for maximal glycogen resynthesis. 1,3,4 more studies are needed that examine the effects of a post-exercise feeding over time and that simulate a normal training programme. addition of protein to cho in a recovery meal the literature concerning the effects of post-exercise ingestion of a cho-pro supplement compared with a cho supplement (i.e. sports beverage) on performance is inconsistent. some studies show improved performance with the cho-pro complex versus a cho only, 11,13,16-21 while others show no difference in performance. 5,22-24 it should be noted that the majority of the literature has examined recovery in trained cyclists or runners when performing a time trial to exhaustion at 70 85% of vo2max. 5,11,13,16,20-24 table i provides a summary of several studies that have investigated the effectiveness of a cho-only beverage versus a cho:pro beverage on recovery indices. protein and muscle glycogen resynthesis protein contributes an estimated 5 15% of total energy expenditure during endurance exercise, 25 which is considerably less than the contribution of carbohydrate. berardi et al. found a significant (p<0.05) improvement in glycogen resynthesis during a 6-hour recovery following a 60-minute cycling time trial with cho:pro (0.8 g.kg -1 cho, 0.4 g.kg -1 pro) in male cyclists (cho:pro 28.6±2.1 mmol.l -1 v. cho 22.2±1.1 mmol.l -1 ), while betts et al. found a significant (p<0.05) increase in insulinaemic response with cho:pro trial (cho:pro 13.5±1.1 miu 240 min -1 .ml -1 v. cho 11.4±0.9 miu 240 min -1 .ml -1 ) during a 4-hour recovery after 90 minutes of running at 70% of vo2max in active runners. 5,22 however, neither of these studies found a difference in performance during a run time to exhaustion at 85% of vo2max 22 or a 60-minute time cycling time trial5 between the cho:pro and cho-only trials. these findings are similar to other studies 6,15-17 which have reported improved glycogen repletion following post-exercise cho-pro supplementation (at a 2 2.9:1 ratio of cho-to-protein). 1 berardi et al. speculated that the self-selected intensity used in the time trial for this study may have impacted performance outcomes. 5 a controlled intensity may have been more beneficial. betts et al. suggested that factors such as protein content, frequency of supplementation, and factors other than carbohydrate availability such as acidosis, which are related to fatigue, may have affected performance. 22 these findings are similar to the earlier-reported studies indicating improved glycogen repletion following post-exercise chopro supplementation compared with cho only, 6,15-17 while others have observed no effects. 5,9,22,23,26 contrary to these findings, ivy et al. found that consuming 200 ml of a solution with a 4:1 ratio of cho-pro (7.75% cho/1.94% pro) every 20 minutes during the recovery period enhanced cycling endurance performance by 36% in trained cyclists versus a cho-only (7.75% cho) solution. reasons for these performance differences among the studies are inconclusive. however, the authors speculated that the results of this study may have been related to maintenance of plasma amino acid levels as it relates to the (branched chain amino acid) central fatigue hypothesis, sparing of muscle glycogen, or retention of krebs’ cycle intermediates. 20 decreased muscle glycogen levels are closely related to fatigue during exercise. 16 the addition of protein to a cho beverage would be practically important if it further increased performance and enhanced recovery between exercise sessions with a short recovery period. current research has examined the impact after intense exercise of adding protein (pro) (~20% of total calories) to a carbohydrate beverage on muscle glycogen resynthesis. prior research suggested that the addition of protein to a post-exercise carbohydrate beverage enhanced glycogen resynthesis due to an increase in insulin levels, thereby enhancing glucose deposits in the muscle. 3,6,17,23 however, it should be noted that the aforementioned investigations were not eucaloric between the beverages. recently, when the energy content of the protein is matched in the beverages, some of these findings regarding the increase in glycogen resynthesis have been refuted. 3 carrithers et al. found no difference in muscle glycogen resynthesis rates when comparing three post-exercise eucaloric (cho, cho:pro, versus a cho:amino acid) beverages administered every 30 minutes during a 4-hour recovery in male collegiate cyclists after a glycogen depletion ride on a cycle ergometer. 23 in contrast, ivy et al. suggested that consumption of a post-exercise cho:pro (80 g cho, 28 g pro, and 6 g fat) beverage enhanced early post-exercise muscle glycogen resynthesis rates after 2.5 hours cycling at 70% of vo2max when compared with a high choonly (108 g cho, and 6 g fat), and low cho-only (80 g cho, and 6 g fat) beverage. in addition, there were no differences in post-exercise insulin concentrations among the three treatments; however, postexercise plasma glucose concentrations were significantly lower with the cho:pro beverage. the authors speculated that the increase in muscle glycogen restoration and decrease in plasma glucose concentrations with a cho:pro beverage may signify enhanced glucose uptake and relocation of intracellular glucose disposal. 15 furthermore, the addition of protein to a post-exercise recovery meal may be beneficial if carbohydrate consumption is below the threshold (<1g.kg -1 ) for maximal glycogen replacement. 3 protein and muscle recovery the addition of protein to a post-exercise recovery meal may also enhance net protein anabolism. 13 during the post-exercise period, there is an increased rate of muscle protein synthesis in trained individuals. 3 the results of literature 6,15-17 seem to be in support of the addition of protein to the recovery beverage. in addition, studies have reported decreases in muscle damage (cpk) with the addition of pro to a recovery beverage after exercise sessions. 8,13,21,25,27,28 both high-intensity and prolonged endurance exercise can damage skeletal muscle, resulting in delayed-onset muscle soreness with concurrent increases in markers of muscle damage such as creatine kinase (ck), myoglobin (mb), cortisol and lactate dehydrogenase (ldh). 29,30 elevated levels of these enzymatic markers are associated with decreased performance. 30 due to the applied nature of recovery studies, the majority of the literature examining muscle damage has included multiple indicators of muscle damage: bloodborne creatine kinase (ck), subjective measures of muscle soreness (using a visual scale). 31 however, ck has been criticised as an effective indicator of muscle damage because of poor correlations with direct measures of muscle damage. research that has examined subsequent exercise performance and muscle damage suggests that a cho:pro v. a cho-only beverage ingested during and after exercise may positively influence recovery. 13,21,25,32 saunders et al. found that the addition of protein to a carbohydrate replacement beverage taken during and after exercise resulted in 83% lower ck levels 12 15 hours after endurance cycling at 85% of vo2max when compared with a cho22 sajsm vol 23 no. 1 2011 sajsm vol 23 no. 1 2011 23 only beverage in trained cyclists. in addition, cyclists performed 40% longer following the consumption of a cho:pro beverage. 13 however, it should be noted that the amount of calories between the two beverages were not equivalent (cho:pro 581 kcals; cho 391 kcals). another study that compared the ingestion of cho:pro gels with cho-only gels during and after a cycling trial at 70% of vo2max to exhaustion in cyclists, found that ck levels were significantly increased (p<0.05) post exercise with the cho-only trial ((pre) 183±116 u.l -1 , (post) 267±214 u.l -1 ) compared with the combined cho:pro trial ((pre)180±133 u.l -1 , (post) 222±141 u.l -1 ). 25 these findings are similar to a study by romano et al., who found that consumption of a cho:pro:antioxidants (cho:pro:a) v. a choonly beverage during and after two consecutive rides to exhaustion (the first ride at 70% of vo2max , followed by a second ride at 80% of vo2max) significantly (p<0.05) attenuated levels of ck (cho: (pre) 203±120 u.l -1 , (post) 582±475 u.l -1 , and cho:pro:a (pre) 188±119 u.l -1 v. 273±169 u.l -1 ), as well as lactate dehydrogenase (ldh), and subjective muscle soreness using a 5-point scale (cho 3.0±5.0, and cho:pro:a 1.0±3.0) after exercise. 8 the two beverages used in this study were matched for caloric content. it is unclear whether decreases in muscle damage and improvements in performance would be seen with post-exercise feedings alone 31 compared with feedings given both during, and after the workout. it should be noted that subjects supplemented both during and post exercise in most aforementioned studies. recently, chocolate milk has been suggested to be an effective, but lower-cost recovery aid due to a cho:pro ratio similar to many commercial recovery and carbohydrate-replacement beverages. 11 chocolate milk is composed of monosaccharides (glucose and fructose) and disaccharides (lactose), while the commercially available recovery beverage consists of monosaccharides (glucose and fructose) and complex carbohydrates (maltodextrin). based on the recommendations (4) regarding post-exercise cho intake, a 70kg male, would need to consume 510 810 ml (70 84 g cho, and 19 30 g pro) and a 60-kg female 435 690 ml (60 72 g cho and 16 26 g pro) of low-fat chocolate milk per hour. karp et al. examined the effectiveness of consuming chocolate milk (choc) as a postexercise recovery aid between two cycling sessions in trained cyclists. after 4 hours of recovery, cycling time to exhaustion at 70% of vo2max was significantly longer for the chocolate milk trial (by ~15 minutes) compared with the recovery beverage (endurox r4, pacifichealth labratories, woodbridge, nj) trial. 11 the differences in performance demonstrated in this study may have been attributed to the different types of carbohydrate in the beverages. because increases in muscle glycogen levels during the early hours of recovery are greater with simple v. complex carbohydrate, 33 perhaps the 4-hour recovery period did not allow enough time for the complete digestion of the complex carbohydrates in the recovery beverage. the authors of this study also speculated whether the higher fat content of chocolate milk may have increased the levels of free fatty acids in the blood, possibly delaying glycogen depletion during the subsequent cycling trial to exhaustion and allowing subject to cycle longer. 11 however, when post-exercise consumption of choc was compared with an isocaloric over-the-counter recovery beverage (crb) (based on 1 g cho.kg -1 of body weight/ hour post-exercise for the first 2 hours) after a highintensity fatiguing trial, the authors found no differences in cycling time to exhaustion at 85% of vo2max. 27 pritchett et al. compared the post-exercise consumption of chocolate milk (choc) to an over-the-counter recovery beverage (crb) matched for cho:pro content and found creatine kinase (ck) was significantly (p<0.05) greater in the crb trial compared with the choc trial (increase choc 27.9±134.8 u.l -1 , crb 211.9±192.5u.l -1 ); with differences not significant for ck post (choc 394.8 ±166.1 u.l -1 , crb 489.1±264.4 u.l -1 ) between the two trials. 27 furthermore, a recent study found similar improvements in endurance performance between a cho:pro and a cho-only beverage when matched for total kilocalories. also, lower plasma ck levels were observed in the cho:pro v. cho-only trial. 21 the majority of studies only examined a single-dose recovery beverage ingested post exercise on muscle damage and performance but did not examine chronic training effects. the potential benefits of the recovery aid may be insignificant if not given adequate time to be effective, especially in highly trained athletes. more recent studies have examined a post-exercise nutritional beverage taken over time (6 days) on muscle damage. luden et al. found significantly (p<0.05) lower ck levels with a cho:pro:a beverage (223.21±160.7 u.l -1 ) versus the choonly beverage (307.3±312.9 u.l -1 ). muscle soreness, using a visual analog scale, was also reported to be significantly (p<0.05) lower after 5 days of post-exercise supplementation with the cho:pro:a beverage (1.0 vas) v. the cho only beverage (2.0 vas). however, the effect of protein on protein synthesis and protein degradation in this study cannot be ruled out. it is not evident whether the results of this study were due to supplementation during exercise, after exercise, or in combination. the authors offered that it cannot be ruled out that the attenuation in ck levels may be due to the additional calories, or improvements in protein synthesis with the cho:pro:a beverage. 26 similarly, skillen et al. reported decreases in ck levels and fatigue following 90 minutes of cycling at 75% of vo2max followed by a time trial to exhaustion at 85% of vo2max after 2 weeks of supplementation in cyclists with a 3.6% cho ±1% amino acid solution. 32 gilson et al. examined the effectiveness of low-fat chocolate milk versus a high cho recovery beverage consumed after exercise for a week in intercollegiate soccer players. 34 the soccer players continued their normal training regimen (which was similar among subjects). similar to the findings of luden et al., 31 this study found significantly (p<0.05) lower cpk (choc: 316.9±188.3 u.l -1 , cho:431.6±310.8 u.l -1 ) levels after one week of supplementation with a beverage containing protein (chocolate milk) v. a high cho-only beverage. however, no differences in performance were reported between beverages. 34 in conclusion, post-exercise recovery beverages containing protein seem to be effective in improving recovery indices. however, some of the results may be due to the higher caloric content of the cho:pro supplements. the additional protein calories via glucogenesis may have provided additional substrate for glycogen resynthesis to occur, therefore aiding in an enhanced recovery. 12 currently research suggests that 20 25 g of high-quality protein during a single feeding is optimal. future research should examine the type of protein, timing of intake, and the effects of distribution of protein throughout the day on recovery indices. 3 type of recovery meals research examining the effects of a post-exercise feeding has exclusively supplemented with a beverage or solid rather than a gel feeding. one reason for this may be that gels are typically consumed during endurance exercise. it appears that the same benefits would be observed with a meal that is in the form of a solid or liquid feeding. 3 consequently, current recommendations are based on research that has examined recovery meals in liquid or solid form. to our knowledge, one study has examined the effects of a postexercise cho-only oral gel versus a cho:pro oral gel on endurance performance and muscle damage. saunders et al. compared the effectiveness of a cho:pro gel to a cho-only gel consumed 24 sajsm vol 23 no. 1 2011 during and after exercise on muscle damage and performance measures. in a cycling time trial to volitional exhaustion at 75% of vo2 peak, subjects cycled 13% longer (p<0.05) with the cho:pro gel compared with the cho-only gel. also, ck levels significantly increased (p<0.05) after exercise with the cho-only gel compared with the cho:pro gel. 25 limitations of studies various limitations have been discussed throughout the studies that have examined post-exercise nutritional strategies for optimal recovery. the vast majority of the studies examined the acute effects of post-exercise recovery on exercise performance. practically it would be more beneficial to examine the effects of these nutritional strategies over a longer duration similar to a training regimen. extraneous variables such as dietary intake and sleep patterns were often not controlled in the studies. in order to examine the effect of a recovery beverage on performance and recovery, it is vital to control for dietary intake. it is ideal to provide a food frequency questionnaire as well as a 3-day food record to get an accurate depiction of diet. sleep is another variable that could influence the results of study, therefore variations in sleep patterns should be considered when comparing trials. over the past 5 years, evidence has suggested a cho:pro beverage may be more beneficial in enhancing endurance performances compared with a cho-only beverage. 35 a major concern that has been addressed in a number of the studies is the inconsistency of the calories between treatments (i.e. cho v. cho:pro beverages). providing isocaloric beverages would be beneficial in determining whether it is the addition of protein, or the additional calories, that are responsible for the results. research on post-exercise nutritional strategies has primarily been done on males. a study by tarnopolsky et al. suggested males oxidise higher proportion of carbohydrate during exercise than females. 36 therefore, recommendations that have been established may only be effective for males and should be examined in females. future research future research should examine isocaloric beverages when comparing beverages of different compositions on recovery. because it is ideal to incorporate a recovery beverage into athletes’ daily regimens, it would be more beneficial to the athletic population to examine the effectiveness of a post-exercise recovery beverage taken on a daily basis. future research should examine other measures of muscle damage. creatine phosphokinase and subjective measures of muscle soreness have been the primary dependent variables in the literature. due to the variable nature of ck, measuring other blood parameters such as ldh, myoglobin and cortisol in conjunction with ck would enhance the quality of the studies. it has also been noted that frequent post-exercise feedings may be beneficial in enhancing glycogen resynthesis. perhaps providing glucose at a metered rate rather than as a bolus would provide higher plasma glucose and insulin levels, resulting in enhanced glycogen resynthesis. 1 therefore research should examine differences in a metered post-exercise feeding v. a large bolus feeding. many athletes, particularly cyclists, consume foods in solid or gel forms during workout or competition. for practical purposes, research should examine differences in solid, liquid and gel forms of recovery meals on muscle glycogen resynthesis, and other recovery measures. practical applications the literature that is available regarding post-exercise nutritional strategies for optimal performance is evolving. we suggest that the optimal timing regarding post-exercise nutritional strategies for maximal glycogen resynthesis is within the first 2 hours after exercise. 6,15-17 also, the literature suggests that 1.0 1.5 g.kg -1 .h -1 may be optimal for recovery. 1,11,15 the addition of 20 25 g of high-quality protein to a recovery meal may aid in muscle protein resynthesis. 3, 6,15-17 references 1. jentjens rl, jeukendrup ae. determinants of post-exercise glycogen synthesis during short term recovery. int j sport nutr exerc metab 2003;33(2):117-144. 2. burke l. fasting and recovery from exercise. br j sports med 2010;44:502508. 3. bishop pa, jones, e, woods k. recovery from training: a brief review. j strength cond res 2008;229(3):1-10. 4. american college of sports medicine, american dietetic association, and dietitians of canada. nutrition and athletic performance. joint position statement of the american dietetic association, dietitians of canada, and the medicine and american college of sports medicine. med sci sports exerc 2009;109:509-527. 5. berardi jm, price tb, noreen ee, lemon pwr. postexercise muscle glycogen recovery enhanced with carbohydrate-protein supplement. med sci sports exerc 2006;38(6):1106-1113. 6. van loon lj, saris wm, ruijshoopanda mk, wagenmakers am. maximizing postexercise muscle glycogen synthesis: carbohydrate supplementation and the application of amino acid or protein hydrolysate. am j clin nutr 2000;72:106-111. 7. ryans m. sports nutrition for endurance athletes, 2nd ed. boulder, co: velopress, 2007. 8. romano-ely bc, todd k, saunders mj, st. laurent t. effect of an isocaloric carbohyrdrate-protein-antioxidant drink on cycling performance. med sci sports exerc 2006;38(9):1608-1616. 9. van hall g, shirreffs sm, calbert jal. muscle glycogen resynthesis during recovery from cycle exercise: no effect of additional protein ingestion. j appl physiol 2000;88:1631-1636. 10. doyle ja, sherman wm, strauss rl. effects of eccentric and concentric exercise on muscle glycogen replenishment. j appl physiol 1993;74:1848-1855. 11. karp jr, johnston jd, tecklenburg s, mickleborough td, fly ad, stager jm. chocolate milk as a post-exercise recovery aid. int j sport nutr exerc meta 2006;16:78-91. 12. ivy jl, katz al, cutler cl. muscle glycogen synthesis after exercise: effect of time of carbohydrate ingestion. j appl physiol 1988;64(4):14801485. 13. saunders mj, kane md, todd mk. effects of carbohydrate-protein beverage on cycling endurance and muscle damage. med sci sport exerc 2004;36(7):1233-1238. 14. blom, pcs. effect of different post-exercise sugar diets on the rate of glycogen synthesis. med sci sports exerc 1987;19(5):491-496. 15. ivy jl, goforth hw, damon bm, mccauley tr, parsons ec, price tb. early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement. j appl physiol 2002;93:1337-1344. 16. williams mb, raven pb, fogt dl, ivy jl. effects of recovery beverages on glycogen restoration and endurance exercise performance. j strength cond res 2003;17:12-19. 17. zawadzki km, yaspelkis bb, ivy jl. carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise. j appl physiol 1992;72:1854-1859. 18. van hall g, saris whm, wagenmakers ajm. effect of carbohydrate supplementation on plasma glutamine during prolonged exercise and recovery. int j sports med 1998;19:82-86. 19. berardi jm, noreen ee, lemon pwr. recovery from a cycling time trial is enhanced with carbohydrate-protein supplementation vs. isoenergetic carbohydrate supplementation. j inter soc sports nutr 2008; 5(24). 20. ivy jl, res pt, sprague rc, widzer mo. effect of a carbohydrate-protein supplement on endurance performance during exercise of varying intensity. int j sport nutr exerc metab 2003;13(3):382-395. 21. valentine rj, saunders mj, todd mk, st. laurent tg. influence of carbohydrate-protein beverage on cycling endurance and indices of muscle disruption. int j sports nutr exerc metab 2008;18:379-388. 22. betts ja, stevenson e, williams c, steppard c, grey e, griffin j. recovery of endurance running capacity: effect of carbohydrate-protein mixtures. int j sport nutr exerc metab 2005;15:590-609. 23. carrithers ja, williamson dl, gallagher pm, godard mp, schulze ke, trappe sw. effects of postexercise carbohydrate-protein feedings on muscle glycogen restoration. j appl physiol 2000;88:1976-1982. sajsm vol 23 no. 1 2011 25 24. green ms, corona bt, doyle ja, ingalls cp. carbohydrate-protein drinks do not enhance recovery from exercise-induced muscle injury. int j sports nutr exerc metab 2008;18:1-18. 25. saunders mj, luden nd, herrcick je. consumption of an oral carbohydrate-protein gel improves cycling endurance and prevents postexercise muscle damage. j strength cond res 2007;21(3):678-684. 26. jentjens rlpg, van loon lj, mann ch, wagenmakers am, jeukendrup ae. addition of protein and amino acids to carbohydrates does not enhance postexercise muscle glycogen synthesis. j appl physiol 2001;93:839-846. 27. pritchett kl, bishop pa, pritchett rc, green jm, katica c. acute effects of chocolate milk and a commercial recovery beverage on post-exercise muscle damage and cycling performance. j appl phys nutr & metab 2009;34(6):1017-1022. 28. ready sl, seifert jl, burke e. the effects of two sports drinks formulations on muscle stress and performance. med sci sports exerc 1999;31:s119. 29. clarkson pm, kearns ak, rouzier p, rubin r, thompson pd. serum creatine kinase levels and renal function measures in exertional muscle damage. med sci sports exerc 2006;38(4):623-627. 30. white jp, wilson jm, austin kg, greer bk, st. john n, panton lb. effect of a carbohydrate-protein supplement timing on acute exercise-induced muscle damage. j int soc sports nutr 2008;5(5). 31. luden nd, saunders mj, todd k. postexercise carbohydrate-proteinanitoxidant ingestion decreases plasma creatine kinase and muscle soreness. int j sport nutr exerc met 2007;17:109-123. 32. skillen ra, testa m, applegate ea, heiden ea, fascetti aj, casazza ga. effects of an amino acid – carbohydrate drink on exercise performance after consecutive-day exercise bouts. int j sport nutr exerc metab 2008;18:473-492. 33. freidman je, neufer pd, dohm gl. regulation of glycogen resynthesis following exercise. sports med 1991;11(4):232-243. 34. gilson s, suanders mj, moran c, moore r, womack cj, todd k. effects of chocolate milk consumption on markers of recovery following soccer training: a randomized cross-over study. j inter soc sports nutr 2010;7(19). 35. baty jj, hwang h, ding z, bernard jr, wang b, kwon b, ivy jl. the effect of a carbohydrate and protein supplement on resistance exercise performance, hormonal response, and muscle damage. j strength cond res 2007;21(2):321-329. 36. tarnopolsky ma, bosman m, macdonald jr, vandeputte d, marti j, roy bd. postexercise protein-carbohydrate and carbohydrate supplements increase muscle glycogen in men and women. j appl physiol 1997;83(6):1877-1883. km_c227-20180711130336 sajsm vol. 26 no. 2 2014 35 original research background. rugby is a physically demanding body contact sport. optimising dietary intake and body composition can positively affect the performance of rugby players. objectives. to determine the body composition, habitual and game-specific nutritional practices of fnb maties varsity cup (mvc) rugby players. methods. a descriptive, cross-sectional study with an analytical component was conducted. of all the mvc rugby players (n=35), 18 completed the sections on body composition and match-day dietary intake, while 11 completed the habitual dietary intake section. body composition data were collected by an international society for the advancement of kinanthropometry-accredited biokineticist. habitual dietary intake data (via a self-administered 7-day food record) and match-day dietary strategies (via telephonic 24-hour recall interview) were collected and compared with nutritional requirements reported by the international olympic committee, the american dietetic association, the american college of sports medicine and the international society of sport nutrition. results. forwards had significantly higher weight (p=0.01), sum of seven skinfolds (p=0.01), percentage body fat (p=0.02), fat mass (p=0.01) and fat-free mass (p=0.01) than backs. compared with current recommendations, group habitual dietary intake (mean (standard deviation)) was inadequate for total energy (45.4 (9.0) kcal/kg body weight (bw)), carbohydrate (4.3 (0.4) g/kg bw), polyunsaturated fatty acids (6.2 (1.7)% of total energy (te)), calcium:protein ratio (6.5:1 (3.5:1)) and copper (2.3 (0.4) mg), while displaying higherthan-recommended intakes for total protein (2.4 (0.7) g/kg bw), fibre (37.7 (7.3) g/day), total fat (33.8 (4.3)% te), saturated fatty acids (11.2 (13.1)% te), cholesterol (766.3 (371.8) mg) and niacin (45.2 (6.9) µg). habitual supplement use was high at 91% (n=10/11). nutritional match-day strategies were excessive for protein (1.2 (0.6) g/kg bw) and fat (0.9 (0.4) g/kg bw) in the pre-event meal, inadequate for energy and carbohydrate during the game and excessive for alcohol (54.4 (59.9) g) after the game. conclusion. forwards and backs differed significantly in various body composition measurements. in relation to observed practices, hab it ual dietary intake and nutritional match-day strategies were suboptimal, with high reported supplement use. players in this sport potentially could benefit from specialist input to optimise dietary strategies and body composition in order to enhance performance. s afr j sm 2014;26(2):35-43. doi:10.7196/sajsm.504 body composition and habitual and match-day dietary intake of the fnb maties varsity cup rugby players s potgieter, bsc dietetics, m nutr, phd nutr sci; j visser, bsc dietetics, m nutr; i croukamp, bsc dietetics; m markides, bsc dietetics; j nascimento, bsc dietetics; k scott, bsc dietetics division of human nutrition, department of interdisciplinary health sciences, faculty of medicine and health sciences, stellenbosch university, tygerberg, cape town, south africa corresponding author: s potgieter (sunita@sun.ac.za) after soccer, rugby is the most popular south african (sa) sport, with a following of ~10 million.[1] development and implementation of new programmes at school, club and university level is one of the sa rugby union (saru)’s aims to reap the long-term benefits in the sport. the annual saru 2012 report emphasised that the successful implementation of the fnb varsity cup presented by steinhoff international reinvigorated university-level rugby and provided the ideal stage on which players can display their skills.[2] this interuniversity competition (comprising eight teams) was initiated in 2008 and is the third leading domestic rugby competition in sa.[2] the maties, a participating team from stellenbosch university, has won the competition three times since its inception. the stellenbosch rugby football club is probably one of the biggest competitive rug by clubs in the world, producing 171 springboks to date, and constituting the nucleus of the rugby teams of the western province.[3] rugby is a physically demanding body contact sport. rugby players should be physically fit, skilled, fast, alert and psychologically stable. [4] the aforementioned factors increase rugby performance by reducing mistakes on the field and the risk of injury.[4] underpinning increased performance are good discipline and optimal nutrition.[4] often within a sport there is variability in the physical characteristics of players. in rugby, there are two broad positions of play, namely forward players (forwards) and backline players (backs). these positions demand different exercise patterns, physical characteristics and nutritional needs.[5] the physical characteristics of elite,[5,6] amateur,[7] adolescent[8-10] and pre-adolescent rugby players have been documented, and it appears that there are well-defined differences between the physical and morphological characteristics of forwards and backs, especially in terms of height and body weight (bw).[5] when tal ented, motivated and highly trained athletes meet to compete, the border between victory and defeat is usually minute; mailto:sunita@sun.ac.za 36 sajsm vol. 26 no. 2 2014 therefore, when everything else is equal, optimal nutrition can be the difference between winning and losing. thus, an adequate diet and nutrient in take can positively affect the performance of athletes.[11] in terms of sport nutrition guidelines, rugby is classified as a field game, utilising strength and power, with patterns of intermittent activity between bursts of high intensity play, followed by rest pauses or periods of lower activity.[12] the work-to-rest ratio can be used to describe a stop-start game such as rugby. the work-to-rest ratio is typically higher for forwards (1:6 7) compared with backs (1:20). [13] the nutritional requirements of rugby players differ depending on playing position, duration and frequency of matches, length of the rugby season, training phase and, as discussed above, positionspecific tasks and physique requirements.[12] objective to the researchers’ knowledge, a comprehensive study of the combina tion of body composition, and habitual and match-day dietary intake of semi-professional and professional rugby players in sa has not been published. the objective of the study was therefore to establish the body composition, habitual and game-specific nutritional practices of maties varsity cup (mvc) rugby players. this information can form the basis of future strategies that can be implemented to optimise the dietary intake and body composition of these players. methods selection and description of participants a descriptive, cross-sectional study with an analytical component was conducted. the study population consisted of male mvc rugby players. census sampling was used to select the participants for the study. the study was approved (n09/10/272) by the health research ethics committee of the faculty of medicine and health sciences, stellenbosch university. subjects gave written informed consent to participate in the study and were assigned a specific reference number linked to their names. this was necessary owing to the fact that data collection took place over a 2-month period that fell within the competitive season (january february 2009). the list of names, reference numbers and contact details was destroyed following data collection to ensure complete confidentiality and anonymity. technical information the study consisted of three main components, assessing (i) body composition, (ii) habitual dietary intake and (iii) game-specific dietary intake. a level 1 international society for the advancement of kinanthropometry-accredited biokineticist collected anthropometric data. body mass index (bmi) was determined from the weight and height of the players. the sum of seven skinfolds (skfs), fat mass, fat-free mass (ffm) and percentage body fat were also determined. the bmi was interpreted according to the world health organization (who) standard guidelines.[14] the sum of seven skfs from the bicep, tricep, subscapular, supraspinale, abdominal, front thigh and medial calf was obtained and interpreted according to normative data for internationaland national-level male athletes. [15] percentage body fat was calculated using the age of the subject in a gender-specific equation incorporating skf thickness at four anatomical sites.[16] for all anthropometrical measurements, the ave rage of two measurements was used and where consecutive measurements differed significantly, the median was used. habitual dietary intake data were collected via a self-administered 7-day food record, and match-day dietary strategies were collected via a telephonic 24-hour recall interview the day after a varsity cup match was played. final-year bsc dietetics students from stellenbosch university collected data under supervision of two registered dietitians. portion sizes in the food record were quantified using standard household measurements and units. the quantities of supplements, such as energy gels and bars, were recorded as the amounts indicated on the packaging. portion sizes with the telephonic 24-hour recall were described using household measures. dietary data were analysed with food finder tm3 for windows software application, version 1.[17] only the macronutrient content of supplements was quantified and added to the total habitual dietary intake. habitual and training/game-specific dietary macronutrient intake was compared with international references.[11,12] estimated energy availability (estea) was calculated according to the international olympic committee (ioc) guidelines.[11] micronutrient intake values were compared with the dietary reference intakes (dris) and a cut-off value of <67% was deemed inadequate. [18] the ratio of calcium:protein was determined and compared with recommendations (20 mg of calcium per 1 g protein).[19] statistics statistical analysis was completed with the assistance of a biostatistician from the centre for statistical consultation, stellenbosch university. data capturing and statistical analysis programs used included statistica (version 11) and microsoft excel (2010) for windows 7. descriptive statistics were reported as means (standard deviations (sds)) for continuous data. to test the difference between the forwards and backs, analysis of variance (anova) was performed. in the case of data not being normally distributed, the kruskal-wallis test was used to test the difference. differences between the two groups were considered statistically significant where p<0.05. results demographic information a total of 35 players took part in the study, of which 13 were forwards and 16 were backs (6 players did not indicate their position of play). the mean (sd) age of the group was 21.9 (1.2) years. the demographic and training characteristics of the players are summarised in table 1. body composition body composition data, with specific reference to weight, sum of seven skfs, percentage body fat, fat mass and ffm differed significant ly between forwards and backs (table 2). habitual dietary intake eleven players returned full data sets (7-day food record). due to the limited number of returned food records from the backs (n=1), data were not compared between forwards and backs. however, when comparing the group’s habitual macronutrient dietary intake to the recommendations (table 3), it was found that the group had an inadequate intake of total energy (te), carbohydrate and sajsm vol. 26 no. 2 2014 37 polyunsaturated fatty acids (pufas), while displaying higherthan-recommended intakes for total protein, fibre, total fat and saturated fatty acids (sfas). in addition to the high intake of total fats and sfas, the mean (sd) cholesterol intake also exceeded recommendations (766.3 (371.8) mg v. the recommendation of 300 500 mg/day).[18] all the mean micronutrient intakes fell within the recommended dri ranges, except for copper intake (2.3 (0.4) mg, 26% of the dri of 9.0 mg/day), which was low, and niacin intake (45.2 (6.9) mg, 283% of the dri and above the upper limit (ul) of 35 mg/day),[18] which was high. although the calcium intake of the players was adequate (1 250 (403) mg/day v. the dri of 1 000 mg/day and below the ul of 2 500 mg/day),[18] when evaluating the calcium intake in relation to the protein intake (calcium:protein ratio), it was notably low (6.5:1 (3.5:1) v. the recommendation of 20:1).[19] dietary supplement use of the eleven 7-day food records received showing habitual dietary intake, 10 players indicated supplement use (91%). of these players, 50% (n=5) indicated they used supplements to provide more energy, 60% (n=6) to increase muscle mass/weight gain, 40% (n=4) to enhance performance, 70% (n=7) to recover from exercise, 30% (n=3) to prevent illness and 10% (n=1) for hydration, stress relief or no reason. supplements used included exercise performance enhancers, weight table 1. demographic and training characteristics all players* (n=35), mean (sd) forwards (n=13), mean (sd) backs (n=16), mean (sd) p-value age (years) 21.9 (1.2) 22.1 (1.2) 22.0 (1.2) 0.50 exercise/day (minutes) 121.0 (18.2) 120.7 (6.5) 123.2 (16.9) 0.74 rugby training/week (hours) 7.5 (1.1) 7.6 (1.3) 7.4 (1.2) 0.77 other training/week (hours)† 5.4 (1.7) 5.3 (2.2) 5.6 (1.7) 0.63 matches played/week (minutes) 98.3 (34.1) 98.5 (35.1) 105.0 (38.3) 0.63 sd = standard deviation. *n=6 players did not indicate whether they were a forward/back. † other training includes gym training, running and cycling (as indicated by the players) table 2. body composition reference range all players (n=18),* mean (sd) forwards (n=7), mean (sd) backs (n=11), mean (sd) p-value international data national data (boksmart)[20] height (m) 1.8 (0.1) 1.9 (0.1) 1.8 (0.1) 0.16 forwards, mean (sd) 1.9 (0.1)[21] 1.810 (0.050) 1.977 (0.040) backs, mean (sd) 1.8 (0.08)[21] 1.793 (0.065) 1.813 (0.055) weight (kg) 95.5 (13.6) 107.0 (11.2) 86.9 (7.7) 0.01† forwards, mean (sd) 111.1 (2.9)[21] 102.4 (905) 118.4 (8.0) backs, mean (sd) 95.7 (2.3)[21] 88.7 (8.3) 100.2 (14.1) bmi (kg/m2) 18.5 24.9[14] 29.2 (3.7) 32.5 (3.3) 27.1 (2.1) 0.01† sum of seven skinfolds (mm)‡ 36.8 85.9[15] 80.5 (27.2) 100.3 (20.5) 67.9 (23.5) 0.01† forwards, mean (sd) 73.3 (19.5) 111.3 (25.3) backs, mean (sd) 57.1 (14.8) 62.0 (17.0) body fat (%) 8 17[5] 18.2 (5.7) 21.9 (4.4) 15.8 (5.3) 0.02† forwards, mean (sd) 15.2 (2.9) 20.0 (3.1) backs, mean (sd) 12.3 (2.2) 13.7 (2.8) body fat (kg) 18.4 (7.8) 24.8 (6.4) 14.3 (5.6) 0.01† ffm (kg) 79.7 (9.0) 87.8 (7.7) 74.6 (5.1) 0.01† sd = standard deviation; bmi = body mass index; ffm = fat-free mass. * complete sets of anthropometry could be obtained from the biokineticist for n=18 players. † indicates statistically significant difference between forwards and backs. ‡ seven skinfolds: bicep, tricep, subscapular, supraspinale, abdominal, front thigh and medial calf[15] 38 sajsm vol. 26 no. 2 2014 gain formulas, muscle builders, recovery enhancers, and protein and carbohydrate supplements. nutritional match-day strategies nutritional match-day strategies were determined for 18 players, of which 10 were forwards and 8 were backs. the macronutrient intake of the rugby players >2 hours before a rugby game was adequate for energy and carbohydrate intake; however, it was too high in protein and fat intake (table 4). no significant differences were found between the pre-event meal of the forwards and of the backs. none of the subjects used supplements immediately before, during or immediately after a rugby match. for the pre-event meal, all the players (n=18) consumed chicken with skin (mean 140.0 (sd 62.0) g), orange juice (407.9 (207.7) ml) and pasta (168.3 (104.0) g) and nine of the players (50%) had eggs (2.7 (1.2) eggs) and brown bread (63.3 (18.0) g) in addition to the abovementioned. no player consumed any food, supplement or sports drink during the rugby game, consuming only water (954.6 (762.1) ml). there was no significant difference between the mean fluid intake during the game between the forwards (1 166.7 (983.2) ml) and the backs (700.0 (308.2) ml) (p=0.34). the macronutrient intake after the game was higher than recommended for carbohydrate, protein and fat intake. the fluid (p=0.02) and energy (including alcohol intake) (p=0.04) intake was significantly higher after the game in the forwards compared with the backs. the players had a very high intake of alcohol after the rugby game, with higher alcohol consumption levels observed in the forwards than in the backs (p=0.07) (table 6). upon calculating the mean total energy intake without alcohol (25.9 (8.2) kcal/kg), it was evident that the total energy intake was even lower than recommendations, although not statistically significant (p=0.31). for the post-event meal, all the players consumed one or more cans of soft drink (585.3 (420.9) ml), 14 (78%) had pasta (107.1 (18.2) g), 13 (72%) had beer (1 326.2 (869.9) ml), 11 (61%) had steers rave burgers (1.5 (0.7) burgers) and 10 (56%) had lasagne (187.5 (90.7) g). only one player consumed a supplement after the rugby game, which provided 36 g carbohydrate per 400 ml fluid (9% carbohydrate solution). the group consumed (5.4 (6.0) alcoholic beverages (6.9 (7.6) units) after the game, with forwards consuming 6.7 (6.7) beverages (8.5 (8.8) units) and backs 2.6 (3.5) beverages (3.4 (4.5) units). discussion body composition endurance, speed, agility, power, flexibility and sport-specific skills are important aspects of well-conditioned rugby players.[5] the results from the present study showed distinct differences between the height, bw, body fat and ffm between the forwards and backs. this is substantiated by literature that has documented well-defined differences between the physical and morphological characteristics of forwards and backs, especially in terms of height and bw.[5,22-24] the average bw of the forwards in our study (~107 kg) was within the normal range when compared with sa data (102 118 kg)[20] and that of new zealand rugby players (~110 kg). the average weight of the backs (~87 kg) was just below the normal range compared with sa data (88 100 kg),[20] but was found to be ~8 kg lighter when compared with that of nz rugby players.[21] national normative data presented by boksmart were used as sa rug by players have shown to be able to compete at an international level. the mean (sd) bmi of the forwards was particularly high (32.5 (3.3) kg/m2); according to the who this is classified as obese. however, the bmi should be interpreted with caution in physically active individuals, as it can incorrectly classify a very muscular person as being overweight. this is true for the backs in our study, as their bmi was 27.1 (2.1) kg/m2, but their mean percentage body fat (15.8 (5.3)%) was just above the national (12 14%) [20] and within international (8 17%) [5] recommendations for rugby players. the percentage body fat of the forwards (~22%) was slightly above national recommendtable 3. habitual dietary macronutrient intakes reference range*† all players (n=11),‡ mean (sd) energy (kcal/kg bw) 50 80[11] 45.4 (9.0) estea (kcal/kg ffm) >30[11] 48.0 (25.1) protein (g/kg bw) 1.2 1.7[11] 1.0 1.5[11] 1.3 1.8[21] 2.4 (0.7) protein (without supplements) (g/kg bw) 1.2 1.7[11] 1.0 1.5[11] 1.3 1.8[11] 1.8 (3.2) carbohydrate (g/kg bw) 6 10[11] 4.3 (0.4) fibre (g/day) 25 30[18] 37.7 (7.3) fat %te 20 35[11] 30[11] 15 20[11] 33.8 (4.3) g/kg bw 1.0 1.5[11] 1.9 (0.5) sfa (%te) 10[18] 11.2 (13.1) mufa (%te) 10[18] 11.2 (1.5) pufa (%te) 10[18] 6.2 (1.7) tfa (%te) <2[18] 0.8 (0.4) sd = standard deviation; bw = body weight; estea = estimated energy availability; ffm = fat-free mass; %te = percentage of total energy; sfa = saturated fatty acids; mufa = mono-unsaturated fatty acids; pufa = polyunsaturated fatty acids; tfa = trans fatty acids. * reference range for macronutrients determined using the amount and level of training of the rugby players (moderate levels of intense training 2 3 hours/day, 5 6 times/week; for moderate levels of intense training the lower level of the range applies (as in this study population); for high-volume intense training the upper level of the range applies). the dietary reference intakes for healthy, physically active individuals were used as a reference range for micronutrient intake – due to the high intake of the players the upper range was used to calculate percentage of total intake. players’ intake was measured during the competitive season (january february 2009). † reference ranges provided are those published by the international olympic committee (ioc), the american college of sports medicine (acsm) and the international society for sports nutrition (issn), the details of which can be found in the review article cited (potgieter, 2013[11]). ‡ of the 11 players who returned the 7-day food record, only eight indicated their position of play (seven forwards, one back). sajsm vol. 26 no. 2 2014 39 ations (15 20%)[20] and ~5% above international recommendations (8 17%).[5] body fat insulates and protects organs and can play a vital role in providing a shield against physical impact experienced by forward players during scrumming;[5] however, it does not contribute to the generation of muscle power and excessive amounts reduce a player’s sprinting ability and influence heat tolerance.[22] backs require more speed as their position of play dictates more running during the game[5] with some tackling required. with increased proficiency in rugby, body fat percentage decreases and bw, specifically muscle mass, increases. [5] the main function of muscle in sport is to contract and generate force,[22] which improves exercise performance.[23] the mvc team won the varsity cup in 2009 (the season in which body composition data was taken). this shows that although there are slight differences in body composition values when compared with national and international data, the team was performing effectively. duthie et al. in 2003[5] and 2006[22] reported that during the 1999 rugby world cup, the most successful teams had higher total bw and that an increased percentage of body fat led to increased energy expenditure, with a subsequent reduction in the power-to-weight ratio and acceleration. the authors concluded that an increased bw is best carried by lean body mass, rather than body fat. therefore, off-season recommendations for the mvc team could include inducing muscle hypertrophy, while reducing fat mass in forward players and increasing weight and muscle mass in backs. this can be achieved by implementing a suitable training programme (including resistance training) in order to provide the competitive advantage and decrease the risk of injury. in-season recommendations to the mvc team would include the maintenance of fitness, strength and power achieved preseason. however, this can be difficult as there is an increased loss of muscle, strength and power during a rugby season because of the increased demand placed on a player’s energy requirements due to training and competition. habitual dietary intake and supplement use comparing the group’s habitual dietary intake to current recommendations, it was found that the group had an inadequate intake of te, carbohydrate, pufa, calcium:protein ratio and copper, and higher-than-recommended intakes for total protein, fibre, total fat, sfa, cholesterol and niacin. although the players had a slightly lower than recommended te intake,[11] it compared favourably to energy intakes found in japanese (41 kcal/kg bw)[25] and australian rugby players (~44 kcal/kg and ~49 kcal/kg bw for forwards and backs, respectively).[23] it appeared from the cross-sectional body composition data that the mvc rugby players were ingesting sufficient te. however, energy balance per se could not be determined as we only had body composition data of one time point during the mvc season. in addition, energy balance (energy in v. energy out) does not provide reliable information about energy requirements, and focuses on an output from rather than input to physiological systems.[11] therefore, determination of estea was of critical importance due to the fact that it is an indication of energy available after energy expended during exercise has been corrected for, thereby showing the impact of a low dietary intake on physiological functions. it has been shown that estea <30 kcal/kg ffm impairs health and exercise performance by specifically suppressing type 1 immunity, which is important for fighting intracellular pathogens such as viruses that commonly cause upper respiratory tract infections in athletes.[11] the high estea found table 4. macronutrient and fluid intake before a rugby game reference range* all players (n=18),† mean (sd) forwards (n=10), mean (sd) backs (n=8), mean (sd) p-value >2 hours before the game energy (kcal/kg bw) 27.2 (8.3) 25.8 (8.6) 29.2 (8.1) 0.44 carbohydrate (g/kg bw) 200 300 (2 3 hours prior)[11] 274.5 (118.8) 299.3 (114.6) 243.6 (124.1) 0.34 1 2 (3 4 hours prior)[11] 1 4 (1 4 hours prior)[11] 2.9 (1.3) 2.8 (1.2) 2.9 (1.6) 0.90 protein (g/kg bw) 0.15 0.25 (3 4 hours prior)[11] 1.2 (0.6) 1.2 (0.4) 1.1 (0.7) 0.90 fat (g/kg bw) 0.9 (0.4) 1.0 (0.4) 0.9 (0.5) 0.64 fluid (ml) hydrate for normal urine output[11] 1 501.9 (813.2) 1 674.0 (796.7) 1 286.9 (833.6) 0.33 1 hour before the game energy (kcal/kg bw) 10.3 (5.3) 8.8 (2.6) 12.2 (7.2) 0.18 carbohydrate (g/kg bw) 1 4 (1 4 hours prior)[11] 1.1 (0.6) 1.0 (0.5) 1.3 (0.7) 0.31 protein(g/kg bw) 0.7 (0.4) 0.6 (0.3) 0.9 (0.5) 0.20 fat (g/kg bw) 0.3 (0.2) 0.3 (0.2) 0.3 (0.3) 0.53 fluid (ml) hydrate for normal urine output[11] 408.4 (375.8) 485.1 (437.1) 312.5 (280.0) 0.26 sd = standard deviation; bw = body weight. * reference ranges provided are those published by the international olympic committee (ioc), the american college of sports medicine (acsm) and the international society for sports nutrition (issn), the details of which can be found in the review article cited (potgieter, 2013[11]). † 17 players could not be reached via phone. 40 sajsm vol. 26 no. 2 2014 in the present study group indicated that the players are consuming sufficient energy to match their physical activity level; however, the backs could benefit from a properly designed training programme and dietary advice in order to increase their lean body mass by ~2 8 kg in support of their position of play. it appeared that the players were ingesting too much protein and fat, at the expense of carbohydrate, the most important macronutrient for exercise performance. in rugby specifically, owing to frequent bursts of short sprints ending in contact, and additional time spent scrumming and tackling, the emphasis is predominantly on carbohydrate utilisation.[12] rugby players can cover a distance of up to 10 15 km in a single game, which increases the risk of glycogen depletion and dehydration.[12] in addition to providing fuel to sustain exercise during the game, carbohydrates also play a critical role in maintaining attention and decision-making abilities.[12] if the rugby players were able to meet their carbohydrate requirements, the use of supplements to recover from exercise and to prevent fatigue would become redundant. recommendations should be made that the participants increase their carbohydrate intake to within the required range.[11] ensuring appropriate timing of carbohydrate in take in relation to training sessions is also of vital importance to sustain and improve exercise performance.[11] this is an important in-season recommendation, especially when the aim is to maintain fitness, strength and power. however, during the off-season, the mvc players are recommended to focus on achieving muscle hypertrophy (both forwards and backs) and therefore, recommendations (as provided by the ioc) should be made to include protein intake at 2.7 g/kg bw and carbohydrate intake at 3 4 g/kg bw[11] during hypoenergetic periods. for this study period, the rugby players were closer to meeting these requirements than those according to their activity level. total habitual protein intake (with supplements, ~2.4 g/kg bw) exceeded the recommended range.[11] compared with sedentary individuals (0.8 g/ kg bw), athletes have increased daily protein requirements.[11] however, increasing protein intake beyond elevated requirements for athletes (1.0 1.8 g/kg bw, increased to 2.7 g/kg bw when a change in body composition is desired out of season) is not recommended. timing of protein intake is an important factor, as is taking into consideration the total energy intake and carbohydrate intake in order to optimise adaptations to training. the majority of the participants took protein supplements and indicated the reason being to recover from exercise. the protein intake calculated without the supplements amounted to ~1.8 g/kg bw, which was much closer to in-season protein recommendations; therefore, additional supplement use should be limited. in a study on 247 canadian university athletes, a prevalence of 98.6% supplement use was found; among males these included carbohydrate gels, protein powders and creatine.[26] in singapore, a study completed by tian et al.[27] found a prevalence of 76.8% supplement use in 82 university athletes, which averaged to about two supplements per day. while an adequate intake of pro tein is necessary to recover from exercise and can be beneficial in terms of muscle adaptation, the players had a high habitual protein intake, attenuating the need for additional supplementation. the low calcium:protein ratio indicates that the players were consuming a high amount of protein in relation to their calcium intake. although the calcium intake per se was adequate when table 5. macronutrient and fluid intake after the rugby game reference range* all players (n=18),† mean (sd) forwards (n=10), mean (sd) backs (n=8), mean (sd) p-value energy (kcal/kg bw) 29.6 (9.8) 31.21 (10.0) 27.5 (9.7) 0.04‡ energy without alcohol (kcal/kg bw) 25.9 (8.2) 26.6 (9.9) 24.6 (7.8) 0.88 carbohydrate 1.0 1.5 g/kg bw[11] 1.5 g/kg bw[11] 1 1.2 g/kg bw/hour[11] 3.2 (1.1) 3.2 (1.0) 3.1 (1.3) 0.91 protein g 20 25[11] 88.0 (40.1) 99.5 (47.4) 73.7 (24.5) 0.18 g/kg bw 0.2 0.5[11] 0.9 (0.4) 0.9 (0.4) 0.9 (0.3) 0.68 fat (g/kg bw) 1.0 (0.5) 1.0 (0.6) 1.0 (0.3) 0.71 fluid immediately after (ml) 1 000 1 500 (water and sodium)[11]§ 433.9 (732.3) 578.0 (922.6) 253.8 (375.8) 0.37 after (ml) 1 744.2 (1 383.4) 2 400.5 (1 436.7) 923.8 (780.6) 0.02‡ alcohol (g)¶ 54.4 (59.9) 67.3 (67.3) 26.1 (35.2) 0.07 sd = standard deviation; bw = body weight; ioc = international olympic committe. * reference ranges provided are those published by the ioc, the american college of sports medicine (acsm) and the international society for sports nutrition (issn), the details of which can be found in the review article cited (potgieter, 2013[11]). † 17 players could not be reached via phone. ‡ statistically significant difference between forwards and backs. § ioc recommends water and sodium to replace losses. ¶ one drink of alcohol contains 10 g alcohol. sajsm vol. 26 no. 2 2014 41 compared with the dri, in relation to protein intake it was not sufficient. although most of the supplements consumed contained between 200 and 250 mg calcium per 100 g pro duct, labelling of the supplements was inconsistent and consumption could not be quantified. the ratio of calcium:protein (without supplements) was ~7:1, compared with the prudent dietary recommendation of 20:1. recommendations could be made to align protein and calcium intakes as this would allow for sufficient calcium absorption; at this stage in their development (age), this would be of vital importance in terms of bone mineralisation, as up to 90% of peak bone mass is acquired by 20 30 years of age. as protein can also have a beneficial effect on bone health, athletes could focus on including calcium-rich sources of protein, such as dairy and dairy products.[28] weight-bearing exercise also plays a protective role in terms of bone health, which in the current study population formed part of their conditioning programme. a combination of weight-bearing exercise, appropriate increase in muscle mass and recommended alignment of protein intake would ensure optimal bone health for these (and other) rugby players. the rugby players’ total habitual fat intake was at the upper end of the range recommended by the american college of sports medicine (acsm)[11] and exceeded the recommended range established by the ioc.[11] pufa intake was inadequate, whereas sfa and dietary cholesterol intake exceeded recommendations consistent with good health. this can lead to an increased risk of heart disease, among other diseases of lifestyle, and may have a negative effect on the players’ rugby performance.[4] the forwards are recommended to modify their eating habits in this regard to decrease body fat percentage. the micronutrient intake of the rugby players in the present study was found to be adequate, except for a low copper intake and a high niacin intake. the elevated niacin intake could have been due to a high habitual intake of chicken and tuna. there are no known symptoms of toxicity of increased dietary niacin intake; however, with supplementation, levels exceeding 3 mg/day can cause flushing, headaches, nausea, vomiting and liver toxicity. [18] there are currently no clear guidelines supporting additional micro nutrient supplement ation in physically active individuals.[11] a healthy, balanced diet, which includes all the different food groups, and adequate exposure to sunlight should provide sufficient micronutrients. optimising the habitual dietary intake of the study group is a challenge. the mvc rugby players are university students as well as semi-professional rugby players, and striking a balance between the two can be difficult. although not specifically recorded in this study, many of the players stay in residences on campus, where meals are provided and they have little control over their dietary intake. student life can also include binge-drinking episodes, which can impact on training and rugby performance. nutritional match-day strategies: before, during and after a match dietary intake during competition forms part of a specific shortterm nutritional strategy aimed at maximising performance at that particular time.[11] the macronutrient intake of the rugby players >2 hours before the rugby game was adequate for energy and carbo hydrate intake, but was high in protein and fat. this was due to popular food choices including chicken with skin, eggs, bacon, muffins and cheese. the players had not received any formal nutritional education and they did not receive a standardised pre-event meal. the only guideline available in terms of pre-event protein intake is from the ioc, which states that although preliminary evidence appears to support increased muscle protein synthesis in response to resistance training when protein is given before exercise, follow-up studies have failed to confirm this finding. athletes can employ this strategy during training when resistance exercise forms part of their conditioning programme; however, before games it is not necessary. a high fat intake is not recommended before an event, as this slows down gastric emptying and may cause gastrointestinal upset.[11] the subjects ingested ~1 l of water during the rugby game. the combined recommendation from the ioc, acsm and international society for sports nutrition (issn) is to calculate individual fluid needs in order to prevent hyperand hypohydration.[11] the issn recommends drinking 500 2 000 ml fluid during every hour of exercise (150 200 ml every 15 20 minutes).[11] although this may seem like an impractical guideline because of restricted opportunity to take in fluid, the players in the present study were comfortably reaching this recommendation with their intake of water. several studies have shown that the start of fatigue during exercise overlaps with the depletion of glycogen in the exercising muscles, and that the fluid recommendation is more a vehicle to provide carbohydrate to improve exercise performance rather than to prevent dehydration (as dehydration in some cases will not impair performance).[11] additional studies have shown that ingestion of carbohydrates during exercise can reduce immunosuppressive effects of exercise and promote muscle glycogen recovery.[11] in addition, carbohydrate intake during exercise can improve cognitive function and tactical decision-making, which is especially important during the second half when blood glucose levels decrease. none of the players in the present study consumed any food, supplements or sports drinks during the rugby game. it is recommended that they consume 30 60 g carbohydrate per hour of exercise.[11] in addition to the 10-minute half-time break, the varsity cup provides a 2-minute break in each half (any 2 minutes between the 18th and 22nd minutes in the first half and between the 58th and 62nd minutes in the second half ). recommendations should be made to use halftime and the strategic-break time to consume at least 250 300 ml of a carbohydrate-electrolyte solution. postexercise consumption of carbohydrates promotes recovery from exercise and replenishes depleted glycogen stores.[11] the group of rugby players in the study had sufficient and even higher-thanrecommended intake of carbohydrate and protein. there is consensus from the acsm, issn and ioc on the beneficial effect of the ingestion of ~20 g (0.2 0.5 g/kg) protein with carbohydrates within 30 minutes post exercise. this recovery strategy can be achieved through dietary sources and additional supplementation is not warranted.[11] although the players had a high intake of al co hol, their postgame energy and carbohydrate intake when calculated without alcohol was still sufficient when compared with recommendations. however, alcohol does interfere with the body’s ability to replenish muscle glycogen and impairs recovery, as discussed below.[29] the fluid intake of the forwards (excluding alcohol) was significantly higher compared with the backs, but both groups reached ioc and acsm requirements to replace water and sodium losses.[11] the players had a very high intake of alcohol after the rugby game, with almost significantly higher levels found in the forwards 42 sajsm vol. 26 no. 2 2014 compared with the backs. the players’ alcohol intake after the match was found to contribute a large amount to their energy and carbohydrate intake, as the drink of choice was beer. consuming alcohol on monday nights after a varsity cup game has become cul ture among university students in sa and the players in the present study were no exception. drinking alcohol after exercise has been shown to increase urinary losses during postrecovery exercise, leading to further dehydration and impeded muscle repair processes. alcohol has vasodilatory effects on the cutaneous blood vessels and may increase swelling around injured areas, in contrast to the swellingdelaying vasoconstrictive practices such as treating with ice, rest and elevation.[29] to the authors’ knowledge, there are no published studies in sa reporting the prevalence of alcohol use after a rugby game. however, studies that have been conducted in germany have found a prevalence of 24% for binge drinking (in 1 month) in 1 138 german young olympic athlete’s lifestyle (goal) and health management study athletes. the goal study also reported a positive relationship between binge drinking and age, education, technical sports, athletes in the lower squads and athletes staying in residences. [30] similarly, studies on french athletes showed a prevalence of 20.4% of bingedrinking episodes in 677 sport science students.[31] in a study on the impact of alcohol consumption on recovery, it was found that acute binge drinking (1 g alcohol/kg bw) after a rugby game adversely affected sleep patterns, lead to increased muscle weakness and decreased lower body vertical power output for days after the game, and that club rugby players were subjected to alcohol-related harm following binge-drinking episodes.[32] it is recommended that the players receive nutrition education, specifically with regard to the effect of alcohol on recovery after exercise. players could perhaps rather include a low alcohol beer with added sodium, which could be socially acceptable but not increase fluid losses after exercise. study limitations a limitation of the present study is that the body composition data obtained were routine data obtained by a biokineticist; due to time constraints and interobserver variability, the fieldworkers could not obtain the outstanding body composition sets. food records are known to place a large burden on subjects and with the present study taking place over 7 days, subject compliance (31%; n=11) and response rate were influenced. other known limitations of food records include overand/or underreporting to make a good impression, and simplifying diet because of recording and literacy issues. conclusions conclusions of this study with regard to habitual dietary intake should be drawn with caution due to the small sample size. future studies should aim to include a larger cohort and to compare the habitual/ training dietary intake of the forwards and backs. results from this study indicate that, as expected, there was a definite distinction in the physical characteristics of the forwards and backs of the mvc rugby team. habitual nutritional intake was inadequate for total energy (although adequate for estea), carbohydrate, pufa, calcium:protein ratio and copper, with high habitual supplement use. the group had higher-than-recommended intakes for total protein, fibre, total fat, sfa, cholesterol and niacin. nutritional match-day strategies were suboptimal. dietary intake and body composition are important complementary factors of the fitness of any rugby player, therefore instilling values with regard to correct timing of nutrient intake and informed use of supplements is of great importance. players of the mvc rugby team could potentially benefit significantly from specialist input, to optimise dietary strategies and body composition to enhance performance. a registered dietitian specialising in sport nutrition could provide individual recommendations (including supplement advice), as well as recommendations for team protocols on prematch menus and food/drink during and after matches. in addition, recommendations on appropriate alcohol consumption should be made, especially in light of optimal recovery strategies and keeping in mind that although this group is considered semi-professional, they are also university students. acknowledgements. the authors would like to thank the coaching staff at the stellenbosch rugby football club, as well as dr p vivier and his team from campus health services, stellenbosch university. references the reference list has been truncated because of the limited number of references permitted by the journal. additional references are available on request from the corresponding author. 1. south african rugby union (saru) annual report 2012. http://www.sarugby.net/ content.aspx?contentid=19255 (accessed 15 august 2013). 2. first national bank, steinhoff international. fnb varsity cup presented by steinhoff international. http://varsitycup.co.za/footer-links-5/about-us (accessed 15 august 2013). 3. stellenbosch rugby football club. http://www.matiesrugby.co.za/about-us (accessed 15 august 2013). 4. lako j, sotheeswaran s, christi k. food habits and nutritional status of fiji rugby players. world ac sci eng tech 2010;4:752-757. http://waset.org/publications/11286 (accessed 21 november 2013). 5. duthie g, pyne d, hooper s. applied physiology and game analysis of rugby union. sports med 2003;33(13):973-991. 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[http://dx.doi. org/10.1136/bjsports-2011-090506] 25. imamura h, iide k, yoshimura y, et al. nutrient intake, serum lipids and iron status of colligiate rugby players. j int soc sports nutr 2013;10:9. [http://dx.doi.org/10.1186/1550-2783-10-9] 26. kristiansen m, levy-milne r, barr s, et al. dietary supplement use by varsity athletes at a canadian university. int j sport nutr exerc 2005;15(2):195-210. 27. tian hh, ong ws, tan cl. nutritional supplement use among univarsity athletes in singapore. singapore med j 2009;50(2):165-72. 28. phillips sm, moore dr, tang je. a critical examination of dietary protein requirements, benefits and excesses in athletes. int j sport nutr exerc metab 2007;17:s58-s76. 29. burke lm, collier gr, broad em, et al. effect of alcohol intake on muscle glycogen storage after prolonged exercise. j appl physiol 2003;95(3):983-990. [http://dx.doi.org/10.1152/ japplphysiol.00115.2003] 30. thiel a, diehl k, giel ke, et al. the german young olympic athletes’ lifestyle and health management study (goal study): design of a mixed-method study. bmc public health 2011;11:410. [http://dx.doi.org/10.1186/1471-2458-11-410] 31. lorente fo, souville m, griffet j, et al. participation in sports and alcohol consumption among french adolescents. addict behav 2004;29(5):941-946. [http://dx.doi.org/10.1016/j. addbeh.2004.02.039] 32. prentice c, stannard sr, barnes mj. the effects of binge drinking behaviour on recovery and performance after a rugby match. j sci med sport 2014;17(2):244-248. [http://dx.doi. org/10.1016/j.jsams.2013.04.011] http://sun025.sun.ac.za/ http://dx.doi.org/10.1210/jcem.85.12.7063] http://www.sarugby.co.za/ http://dx.doi.org/10.1080/02640410600944659] http://dx.doi.org/10.1080/02640410600944659] http://boksmart http://dx.doi.org/10.1136/bjsports-2011-090506] http://dx.doi.org/10.1136/bjsports-2011-090506] http://dx.doi.org/10.1186/1550-2783-10-9] http://dx.doi.org/10.1152/japplphysiol.00115.2003] http://dx.doi.org/10.1152/japplphysiol.00115.2003] http://dx.doi.org/10.1186/1471-2458-11-410] http://dx.doi.org/10.1016/j.addbeh.2004.02.039] http://dx.doi.org/10.1016/j.addbeh.2004.02.039] http://dx.doi.org/10.1016/j.jsams.2013.04.011] http://dx.doi.org/10.1016/j.jsams.2013.04.011] original research 1 sajsm vol. 30 no. 1 2018 the short-term effects of a sport stacking intervention on the cognitive and perceptual motor functioning in geriatrics: a pilot study r naidoo, phd (sports science), k moodley, m sports science discipline of biokinetics, exercise and leisure sciences, university of kwazulu-natal, college of health sciences, south africa corresponding author: r naidoo (naidoor3@ukzn.ac.za) sport stacking is defined as an individual or team activity where participants stack and unstack specially designed plastic cups in predetermined sequences while racing against the clock or an opponent.[1] sport stacking is an activity usually associated with, and performed by, children. it is easy to learn and has the potential to improve hand-eye coordination.[2] it has been claimed that sport stacking allows for an enhancement of motor skills, such as directionality, laterality, perceptual motor functioning, crossing the midline and handeye coordination.[1] motor skills are subject to accelerated and progressive decline after the age of 60 years.[3-4] age is a major contributor to lower reaction times affected by decreases in central processing speed, decreases in passive joint flexibility, more caution before responding to certain tasks, and changes in neuromuscular properties.[5] the upper extremities, specifically the hands, play a vital and active role in the activities of daily life. the hands are also subjected to numerous age-related physiological and anatomical changes that can lead to diminished function.[6] furthermore, the relationship between increased age and reduced hand dexterity has been widely reported in both the clinical and scientific literature.[7] together with a decrease in reaction time in hand precision and dexterity, ageing also results in a decrease in muscular strength, which in turn affects proprioception.[8] balance is dependent on sensory and musculoskeletal systems which are also affected by the ageing process. geriatrics who have experienced a fall lose confidence in their physical capabilities, which results in them being hesitant to participate in physical activity/exercise.[9] in addition, as ageing progresses, memory loss, a reduction in learning ability and a decrease in cognitive functioning occurs.[10] physical inactivity is also associated with an increased risk of cognitive impairment.[11] it is evident that the process of ageing affects both motor and cognitive skills. interventions to improve motor and cognitive functioning may be beneficial in improving cognitive functioning and quality of life.[12] however, to the best of these authors’ knowledge, there are no interventions that have included a sport stacking component for geriatrics in their protocol. hence, the aim of this study was to determine the short-term effects of a sport stacking intervention programme on the motor functioning (hand-eye coordination, reaction time, balance), cognitive functioning (memory) and quality of life in geriatrics. methods design this study was an experimental study with a preand postintervention assessment. permission to conduct this study was given by the association for the aged in kwazulu-natal, south africa, and ethical clearance from the university of kwazulu-natal’s biomedical research ethics committee (bfc 186/15) was also granted. participants this was a convenient sample consisting of 60 geriatrics aged between 60 and 89 years who volunteered to participate in the study. they were recruited from a local retirement home in kwazulu-natal. the sample adhered to the following inclusion criteria: no physical disabilities, not diagnosed with alzheimer’s or parkinson's disease, no sport stacking experience, not on medication for vertigo, no orthopaedic complications, and a sedentary lifestyle. a call for participants was posted on flyers at the retirement home. the 60 participants who met the inclusion criteria completed informed consent forms and were then randomly assigned into either the intervention (n=30) or control (n=30) group, and were assigned by means of a random participant code. the participants were only informed of their group allocation once the pre-intervention tests were completed. the background: sport stacking has been found to be beneficial in improving reaction time, as well as hand-eyecoordination, in children. aim: the aim of this study was to determine the effects of a sport stacking physical activity intervention on the motor and cognitive functioning of geriatrics. methods: an intact, convenient sample of 58 geriatrics from a retirement home in kwazulu-natal, south africa, was selected to participate in this study. twenty-eight participants were exposed to an eight-week intervention consisting of 16 physical activity sessions, combined with sport stacking techniques, while the control group (30 participants) continued with activities as usual. all participants performed selected motor and cognitive functioning tests, preand postintervention. results: the intervention group had greater improvements in mean reaction time and plate tapping (hand-eye coordination) times compared to the control group. there were no changes in the balance test, memory and quality of life tests. conclusion: a sport stacking activity intervention may improve reaction times and hand-eye coordination in geriatrics. keywords: hand-eye coordination, quality of life, reaction time s afr j sports med 2018;30:1-6. doi: 10.17159/2078-516x/2018/v30i1a4267 mailto:naidoor3@ukzn.ac.za http://dx.doi.org/10.17159/2078-516x/2018/v30i1a4267 original research sajsm vol. 30 no. 1 2018 2 authors were responsible for the recruitment and group allocation of the participants. tests preand post-intervention test measurements included body mass index (bmi), and motor and cognitive functioning. motor functioning tests for hand-eye coordination (plate tapping test), reaction time (position speed test), quality of life (lawton’s instrumental activities daily living questionnaire), and balance (sharpened romberg test) were administered. the cognitive functioning test for memory utilised the short orientation memory concentration test (somct). all tests were conducted three days prior to the start of the intervention and three days post-intervention. the intervention the eight-week sport stacking physical activity intervention consisted of two 60 minute weekly sessions. the sessions were conducted as a 25 minute session with a short ten minute break, and then another 25 minute session. the intervention consisted of a multi-stage progression from basic to advanced techniques of sport stacking, as well as progression from slow to fast speeds when performing the techniques. a physical activity component of walking/jogging/running relays was also included. sport stacking relays were conducted at the end of sessions as a fun element. relay teams performed a stacking sequence and would then walk/jog/run 10 to 15 m and tag their partner to sport stack, and so on. in addition, participants performed sit-downs, stand-ups and balancing on one foot as part of the relay. participants were required to learn three different sport stacking sequences which were the 3-3-3 (figure 1), 3-6-3 (figure 2) and the cycle stack (figure 3). the techniques were designed to use both hands. sport stacking times were measured and recorded for the intervention group per session. the intervention group participated in the sport stacking physical activity intervention, while the control group remained sedentary and continued with their daily schedules as usual. on completion of the study, the intervention was offered to the control group. instrumentation body mass index (bmi) was assessed according to the american college of sports medicine guidelines.[13] height and weight were measured by using the nagata bw-1122h measuring tool. the scale was calibrated before testing. thereafter, the bmi was calculated for each participant. plate tapping test the plate tapping test assessed the speed and the coordination of limb movement. it utilised a table with adjustable height and a plate tapping board. the plate tapping board was comprised of two green discs of at least 20 cm in diameter and 60 cm apart on a rectangular piece of wood. participants placed their nonpreferred hand between the two green discs, then moved their preferred hand back and forth between the green discs over their hand in the middle as quickly as possible. this timed action was repeated for 25 full cycles (50 taps). the best time of two attempts was recorded. position speed test the position speed test was an online computer-based test that assessed simple reaction time. participants were required to respond as quickly as possible to an orange square that appeared on a grid table on the screen. once the participant clicked on the orange square it randomly moved to another block on the grid. the participants had 30 seconds in which to click on as many orange squares as possible to determine the fig. 1. 3-3-3 sport stacking sequence fig. 2. 3-6-3 sport stacking sequence fig. 3. the cycle stack original research 3 sajsm vol. 30 no. 1 2018 speed of their reactions. they had two attempts at the test and the best score was recorded. sharpened romberg test balance and proprioception were assessed using the sharpened romberg test. the participants stood in three different positions in sequence: feet together, semi-tandem, and tandem. each position was held for ten seconds by the participants, with their eyes open and then another ten seconds with their eyes closed. they had three tries to reach the maximum time of 60 seconds. the longest balance time of the three tries was recorded as their score. the semi-tandem and tandem positions were performed in a heel-to-toe standing position with the dominant foot behind the nondominant foot. if the participants moved their feet from this position, opened their eyes during the “closed eyes” phase or reached the maximum test time of 60 seconds, the timer was stopped. those who successfully completed two out of three tests were scored as “balanced”. lawton’s instrumental activities of daily living questionnaire this was a functional assessment of the participants’ independence, which measured functioning at the present time and attempted to determine improvement or deterioration in functioning. it measured the use of a telephone, shopping, food preparation, housekeeping, laundry, mode of transportation, responsibility for medication, and the ability to handle personal finances. the scoring was as follows: one (1) point was given when able to perform the tasks and zero (0) points were given when unable to perform the task. the higher the score, the more capable, and the lower the score, the greater need for dependence on another person. the final score was out of eight. short orientation memory concentration test (somct) the somct assessed memory, and was comprised of six questions. these questions were such as ‘what year is it?’, ‘about what time is it?’, ‘say the months in reverse order’ as well as the repetition of phrases. the test used a negative scoring scale. each question had a maximum number of errors allowed. the scores for each question were added together to give a total error score out of 28. a score of zero to six was within normal limits, while scores of seven and above would indicate a need for further evaluation to rule out a demention disorder, such as alzheimer’s disease. all tests took approximately an hour per participant and were conducted over two days, preand post-intervention. the tests were conducted by trained exercise scientists, and were supervised by the authors/researchers. all tests were standardised and conducted by the same exercise scientist pre and post-intervention. exercise scientists were blinded to the group assignment process to ensure the standardisation of the programme. this assisted with programme adherence as participants developed a rapport with the researcher and were motivated and enthusiastic to attend the sport stacking physical activity intervention sessions. statistical analysis all the data collected in this study was subjected to various statistical procedures. all the data were analysed using the statistical package for the social sciences version 19. descriptive (means and standard deviations) and inferential (ttests, ancova) statistics were used to test significant differences preand post-intervention. t-tests were used to test for significant differences across time within groups and ancova was used to test for significant differences over time between groups. the changes in the mean and standard deviations were compared to the preand post-test scores for the intervention and control groups respectively. cohen's d was used to describe the standardised mean difference of an effect. sport stacking scores were also analysed to determine whether the participants’ times decreased (improved) during the intervention. the non-parametric sign test was used to analyse the data from the balance test. statistical significance was set at p<0.05. table 1. preand post-test motor functioning results for the control (n=30) and intervention (n=28) groups components control mean (sd) intervention mean (sd) pre post p-value pre post p-value plate tapping test (s) 29.14 (10.03) 27.60 (11.46) 0.015* t(29)= 2.6 22.32 (3.34) 19.70 (2.88) 0.001* t(27)= 5.6 position speed test (s) 15.30 (9.61) 17.23 (±8.29) 0.037* t(29)= -2.2 16.36 (6.86) 20.82 (7.04) 0.001* t(27)= -5.9 lawton’s instrumental activities of daily living questionnaire (score) 7.60 (0.77) 7.77 (0.57) 0.134 t(29)= -1.5 7.71 (0.74) 7.89 (0.32) 0.134 t(27)= -1.5 data expressed as mean ± sd. * indicates p value <0.05 table 2. preand post-test cognitive functioning results for the control (n=30) and intervention (n=28) groups components control mean (sd) intervention mean (sd) pre post p-value pre post p-value short orientation memory concentration test (score) 3.93 (4.04) 3.00 (3.17) 0.109 t(29)=1.7 3.50 (4.18) 2.50 (2.67) 0.204 t(27)=1.3 data expressed as mean ± sd. original research sajsm vol. 30 no. 1 2018 4 results pre-intervention included a 100% compliance of the 60 participants. however, due to adverse events (the death of two participants), the data presented represents 58 participants (28 in the intervention group; 30 in the control group). participants ages ranged from 60 to 89 years, with a mean age of 73 years for the sample. the mean age in the intervention group was 73 (±8) years and 73 (±7) years in the control group. a total of 12 males and 48 females participated in the study. the intervention group was comprised of five males and 23 females while the control group was comprised of seven males and 23 females. the mean bmi pre-intervention was 28.98kg/m2 and postintervention was 29.00kg/m2. motor functioning components table 1 shows the preand post-test t-test results for the control and intervention groups. it is evident that there was a significant difference in the plate tapping test and simple reaction time test scores. the intervention group presented with a significant difference in the plate tapping test and the reaction time test. the control group also presented with a significant difference in the plate tapping test and the reaction time test. further analysis showed that the effect size for the intervention group’s plate tapping analysis (d=0.85) exceeded cohen’s d [14] convention for a large effect (d=0.80), whereas the control group had a trivial change (d=0.14). similarly, the intervention group’s reaction time test analysis (d=0.64) exceeded cohen’s d [14] convention for a moderate effect (d=0.50), whereas the control group change was small (d=0.22). when ancova was applied, a significant difference in the reaction time test for the two groups after correcting for the pre-reaction measure (f(1,55) = 6.6, p=0.013) was found. the post-intervention reaction test score was significantly higher for the intervention group than for the control group. for the balance test, a non-parametric sign test was applied to the pairs of measurements to determine if there were significant differences preand post-intervention. the sharpened romberg test’s preand post-intervention mean scores were not significant. cognitive functioning components table 2 depicts the preand post-test results for the control and intervention groups. there were no significant differences between the control and intervention groups. sport stacking times results indicated improvements in sport stacking times. average times clearly decreased over time (figures 4, 5 and 6). there was a significant effect of time on stacking 3-3-3, f(7.42) = 19.2, p<0.0005). there was a significant effect of time on stacking 3-6-3, f(1.43) = 6.1, p=0.029). there was a significant effect of time on stacking the cycle, f(2.14) = 20.0, p<0.0005). re ad in g 1 re ad in g 2 re ad in g 3 0 50 100 150 sss:3-3-6 * ti m e ( s ) fig. 6. cycle sport stacking sequence time changes. * indicates p<0.05 re ad in g 1 re ad in g 2 re ad in g 3 re ad in g 4 re ad in g 5 re ad in g 6 re ad in g 7 0 10 20 30 40 sss:3-3-6 * ti m e ( s ) fig. 5. 3-6-3 sport stacking sequence time changes. * indicates p<0.05 sss: 3-6-3 cycle re ad in g 1 re ad in g 2 re ad in g 3 re ad in g 4 re ad in g 5 re ad in g 6 re ad in g 7 re ad in g 8 0 5 10 15 20 sss:3-3-3 * ti m e ( s ) fig. 4. 3-3-3 sport stacking sequence time changes. * indicates p<0.05 sss: 3-3-3 original research 5 sajsm vol. 30 no. 1 2018 discussion this study showed there was a positive effect on the participants’ hand-eye coordination and reaction times in both the intervention and control groups. this could be attributed to a learning effect as participants practised sequences and remembered the techniques. possible reasons for the significant improvements in the control group may be due to participants being motivated to improve their physical activity because of their increased health risks, or as a result of the hawthorne effect: the alteration of behaviour by the subjects of a study due to their awareness of being observed.[15] however, even though there was a significant improvement in plate tapping in both groups, the effect size in the intervention (d=0.85) group was larger than that of the control group (d=0.15). khemthong et al.[16] conducted a study on the effects of musical training on reaction time in elderly individuals and showed that there was almost a 19% increase in visual reaction time. similarly, in the current study, both the control and intervention groups demonstrated statistically positive increases in reaction time post-intervention. this could be due to both groups now being familiar with the test, although the effect size of the intervention group’s improvement (d=0.64) was larger than that found in the control group (d=0.22). furthermore, the skill of sport stacking also improved significantly improved over time, which could have contributed to the improvements in the intervention group. the current study did not show an improvement in memory, post-intervention. however, other physical activity intervention studies have been shown to improve memory functioning in geriatrics, specifically when memory loss is detected early, as this may allow for a physical activity intervention to be implemented.[17] colcombe et al.[18] showed that adults who participated in a regular walking protocol experienced improvements in their cognitive functioning. a study conducted by wolf et al.[19] in geriatrics who presented with balance problems found that after a four-tosix-week intervention of 12 individualised balance exercises, significant improvements in balance were noted. however, in the current study, no significant differences in balance were found post-intervention. this could be due to the balance activities having been integrated into the intervention and not been the primary focus of the study and/or individualised. visible change, despite the equivocal results, suggests that sport stacking has the potential to improve hand-eye coordination in geriatrics. it is apparent that studies relating to sport stacking are limited. additional research needs to be conducted on the cognitive effects of sport stacking, as well as its shortand long-term effects on the geriatric population. the clinical implications for this study are positive: sport stacking could be a therapeutic option for geriatrics to help promote improvements in hand reaction time and hand-eye coordination. a long-term sport stacking intervention and larger samples may be needed to ascertain whether it is associated with improvements in both motor and cognitive functioning. limitations there were several limitations in this study. first, there was no random selection, so results are not representative of the geriatric population as a whole. the small sample size influenced the significance of selected results. the study participants were geriatrics from a retirement/old age home and therefore the results are specific to this population and not to geriatrics living in the wider community. furthermore, the majority of the participants were female (83%). conclusion in conclusion, following 16 physical activity sessions combined with sport stacking techniques, there were improvements in mean reaction time and plate tapping (hand-eye coordination) times. these findings show that a sport stacking activity intervention may improve reaction times and hand-eye coordination in geriatrics. acknowledgements: the authors would like to acknowledge and thank the participants at the retirement home who willingly participated in this study. conflict of interest: the authors declare no conflict of interest with respect to the authorship and/or publication of this article. funding: this study was funded by the college of health sciences, university of kwazulu-natal. references 1. speed stacks. sport stacking* with speed stacks: a rationale. https://www.jmu.edu/kinesiology/hpainstitute/documents/spee dstackingrationale.pdf. accessed 12 january 2016. 2. udermann be, murray sr, mayer jm, et al. influence of cup stacking on hand-eye coordination and reaction time of secondgrade students. percept mot skills 2004; 98(2):409-414. [doi: 10.2466/pms.98.2.409-414] 3. stöckel t, wunsch k, hughes cm. age-related decline in anticipatory motor planning and its relation to cognitive and motor skill proficiency. front aging neurosci 2017; 9:283. [doi: 10.3389/fnagi.2017.00283] 4. figueiredo pa, mota mp, appell hj, et al. ceasing of muscle function with aging: is it the consequence of intrinsic muscle degeneration or a secondary effect of neuronal impairments? eur rev aging phys act 2006; 3:11. [doi: 10.1007/s11556-006-0011-9] 5. welford at. motor performance. in: j e birren, kw schaic (eds). handbook of the psychology of aging. 2nd ed. new york: van nostrand reinhold, 1977:450-496. 6. carmeli e, patish h, coleman r. the aging hand. j gerontol a biol sci med sci 2003; 58(2): m146m152. [doi:10.1093/gerona/58.2.m146] 7. martin ja, ramsay j. hughes c. et al. age and grip strength predict hand dexterity in adults. plos one 2015, 10(2), e0117598. [doi: 10.1371/journal.pone.0117598]. 8. hurley mv, rees j, newham dj. quadriceps function, proprioceptive acuity and functional performance in healthy young, middle-aged and elderly subjects. age ageing 1998; 27(1):55-62. [doi: 10.1093/ageing/27.1.55] 9. matsumura ba, ambrose af. balance in the elderly. clin geriatr med 2006; 22(2):395-412. [doi: 10.1016/j.cger.2005.12.007] 10. pang fc, chow tw, cummings jl, et al. effect of neuropsychiatric symptoms of alzheimer’s disease on chinese https://doi.org/10.1093/gerona/58.2.m146 https://doi.org/10.1093/ageing/27.1.55 original research sajsm vol. 30 no. 1 2018 6 and american caregivers. int j geriatr psychiatry 2002; 17(1):2934. [doi:10.1002/gps.510] 11. cotman cw, berchtold nc. exercise: a behavioral intervention to enhance brain health and plasticity. trends neurosci 2002; 25(6): 295-301. [doi:10.1016/s0166-2236(02)02143-4] 12. sayer aa, robinson sm, patel hp, et al. new horizons in the pathogenesis, diagnosis and management of sarcopenia. age ageing 2013; 42(2):145-150. [doi: 10.1093/ageing/afs191] 13. pescatello, linda s. acsm's guidelines for exercise testing and prescription. philadelphia: wolters kluwer/lippincott williams & wilkins health, 2014: 63-64 14. cohen, j. statistical power analysis for the behavioral sciences. 2nd ed. new jersey: l eribaum, 1988: 2-27. 15. waters l, reeves m, fjeldsoe b, et al. control group improvements in physical activity intervention trials and possible explanatory factors: a systematic review. j phys act health 2012; 9 (6): 884-895. 16. khemthong s, pejarasangharn u, uptampohtiwat t, et al. effect of musical training on reaction time: a randomized control trial in thai elderly individuals. music med 2012; 4(1):16-21. [doi: 10.1177/1943862111427567] 17. cockburn j, collin c. measuring everyday memory in elderly people: a preliminary study. age ageing1988; 17(4):265–269. [doi:10.1093/ageing/17.4.265] 18. colcombe sj, kramer af, erickson, ki, et al. cardiovascular fitness, cortical plasticity, and aging. proc natl acad sci u s a 2004; 101(9):3316-3321. [doi: 10.1073/pnas.0400266101] 19. wolf b, feys h, de weerdt w, et al. effect of a physical therapeutic intervention for balance problems in the elderly: a single-blind, randomized, controlled multicenter trial. clin rehabil 2001; 15(6):624-636. [doi: 10.1191/0269215501cr456oa] https://doi.org/10.1002/gps.510 https://doi.org/10.1093/ageing/17.4.265 sajsm 543.indd original research sajsm vol. 26 no. 4 2014 123 background. injury surveillance is fundamental to preventing and reducing the risk of injury. objectives. to determine the incidence of injuries and the injury demographics of elite schoolboy cricketers over five seasons (2007 2008, 2008 2009, 2009 2010, 2010 2011 and 2011 2012). methods. sixteen provincial age group cricket teams (under (u) 15 , u17 and u18) competing in national age-group tournaments were provided a questionnaire to complete. the questionnaires gathered the following information for each injury sustained in the previous 12 months: (i) anatomical site; (ii) month; (iii) cause; (iv) whether it was a recurrence of an injury from a previous season; (v) whether the injury had reoccurred during the current season; and (vi) biographical data. injuries were grouped according to the anatomical region injured. all players were invited to respond, irrespective of whether an injury had been sustained, resulting in a response rate of 57%. the sample statistical analysis system was used to compute univariate statistics and frequency distributions. results. of the 2 081 respondents, 572 (27%) sustained a total of 658 injuries. the u15 and u17 groups sustained 239 (36%) and 230 (35%) injuries, respectively, more than the 189 injuries sustained by the u18 group (29%). these injuries were predominantly to the lower limbs (38%), back and trunk (33%) and upper (26%) limbs, with 3% occurring to the head and neck. the injuries occurred primarily during 1-day matches (30%), practices (29%) and with gradual onset (21%). the primary mechanism of injury was bowling (44%) and fielding (22%). the injuries were acute (49%), chronic (41%) and acute-on-chronic (10%), with 26% and 47% being recurrent injuries from the previous and current seasons, respectively. some similar injury patterns occurred in studies of adult cricketers, with differences in the nature and incidence of injuries found for the various age groups. the youth cricketers sustained more back and trunk injuries, recurrent injuries and more match injuries than the adult cricketers. the u15 group sustained less-serious injuries, which resulted in them not being able to play for between 1 and 7 days (58%), with more injuries occurring in the preseason period (24%) and fewer during the season (60%) compared with other age groups. the u15 and u17 groups sustained the most lumbar muscle strains, while the u18 groups sustained more serious injuries, resulting in them not being able to play for >21 days. conclusion. young fast bowlers of all ages remain at the greatest risk of injury. differences in the nature and incidence of injuries occurred between youth and adult cricketers, as well as in the different age groups. it is recommended that cricket administrators and coaches implement an educational process of injury prevention and management. s afr j sm 2014;26(4):123-127. doi:10.7196/sajsm.543 junior cricketers are not a smaller version of adult cricketers: a 5-year investigation of injuries in elite junior cricketers r a stretch, dphil sport bureau, nelson mandela metropolitan university, port elizabeth, south africa corresponding author: m lambert (mike.lambert@uct.ac.za) injuries in elite adult cricketers have been well researched over the years, with long-term injury surveillance being carried out in australia,[1] england[2] and south africa (sa).[3] however, there remains a relative lack of published studies on injury patterns and risk factors in young cricket players, particularly studies reporting injuries with large sample sizes and over more than one season. seven studies have described injuries in junior cricketers in sa,[4-7] australia[8,9] and new zealand.[10] these studies reported that young cricketers sustain proportionally less overuse injuries than elite players, but were more susceptible to acute traumatic injuries. in a retrospective study on schoolboy cricketers,[4] the seasonal incidence of injury was reported to be 49%, with the most common sites of injury being the back and trunk (33%), and upper (25%) and lower (23%) limbs. bowlers sustained more injuries (47%) than batsmen (30%) and fielders (23%). the injuries occurred equally during matches (46%) and practices (47%), with 30% of the injuries recurrent from previous seasons and 37% recurring again during the same season. a 34% seasonal incidence, with injuries occurring during matches (72%) throughout the season due to repetitive stresses sustained during matches and practices (15%), during practice (12%) and during other forms of training (1.5%), was reported for 196 schoolboy cricketers who competed in an under (u) 19 provincial competition.[5] bowling accounted for 51% of the injuries, fielding 33%, batting 15% and the remaining 1.5% occurred while warming up or training. the primary mechanism of injury occurred during the delivery stride and follow-through of the fast bowler (34%). a large number of injuries (41%) reported were severe and took the cricketers >21 days to recover. adolescent cricketers reported musculoskeletal injury in the lower (39%) and upper (36%) limbs and the lower back (18%).[6] direct physical trauma and overuse were the main causes of this musculoskeletal pain, with the knee being the primary site of injury. findings for the current study were reported after the initial 3-year period and showed that 366 (28%) of the 1 292 respondents sustained a total of 425 injuries.[7] the u15 and u17 groups sustained 166 (39%) and 148 (35%) injuries, respectively, more than the 111 injuries sustained by the u18 group (26%). these injuries were predominantly 124 sajsm vol. 26 no. 4 2014 to the lower (46%) and upper (35%) limbs, and occurred primarily during 1-day matches (31%), practices (27%) and with gradual onset (21%). the primary mechanism of injury was bowling (45%) and fielding, including running to field the ball (33%). forty-two lumbar muscle strains, 18 hamstring strains, 17 spondylolisthesis injuries and 17 ankle sprains occurred. the injuries were acute (50%), chronic (42%) and acute-on-chronic (8%), with 24% and 46% being recurrent injuries from the previous and current seasons, respectively. slight differences in the nature and incidence of injuries were found for the various age groups. the u15 group sustained less-serious injuries, which resulted in them not being able to play for between 1 and 7 days (54%), with more injuries occurring in the preseason period (28%) than the other groups. the u17 group sustained the most lumbar muscle strains (n=23), while the u18 group sustained more serious injuries, with 60% of the injuries resulting in not being able to play for ≥8 days. traditional cricket was associated with more injuries than modified cricket, with batting (49%) and fielding (29%) accounting for the majority of injuries. impact by the ball was responsible for 55% of the injuries. the introduction of compulsory wearing of protective head gear when batting resulted in a decrease in head, neck and facial injuries from 62% to 35% to 4% over a three-season period.[8] in junior club cricketers, injury rates increase with age and level of play,[8] and injuries to fielders and batsmen occur as frequently as to bowlers.[9] match injury rates (per 1 000 participations) were 3.57 for u14 participations compared with 4.80 for u16 participations. training injury rates were 4.20 per 1 000 u14 participations compared with 5.11 per 1 000 u16 participations. in matches, more injuries occurred while batting and fielding, while more injuries occurred while bowling and batting during training sessions. most of the 47 injuries were acute and traumatic in nature, with many associated with being struck by the ball. data on the cricketers hospitalised after sustaining an injury showed differences among age groups, with 50% of the injuries to players <10 years of age being head injuries as a result of being struck by the bat.[10] those cricketers between the ages of 10 and 19 years sustained head (34%), upper (28%) and lower (29%) limb injuries primarily as result of impact from the bat or ball. a further four studies have focused on injury prevention strategies in young high-performance fast bowlers in sa,[11] australia[12] and england.[13,14] in addition, there is a report on injury risk of junior australian cricketers, associated with ground hardness.[15] in the sa study, 31 of the 46 fast bowlers assessed sustained an injury during the season, with strains to the knee (41%) and lower back (37%) being the most common injuries.[11] a relationship between a high bowling workload and injury in the young australian fast bowlers was reported, with the injured bowlers being those who bowled more frequently with shorter rest periods between bowling sessions than uninjured bowlers. the bowlers who bowled more than 50 deliveries per day and who bowled on average more than 2.5 days per week were at the greatest risk of injury.[12] a study investigating the incidence of injury in young spin and fast bowlers reported fewer injuries for the spin bowlers (0.066 per 1 000 balls) compared with fast bowlers (0.165 per 1 000 balls).[13] in fast bowling, the incidence of injury (per 1 000 balls) was greatest at the knee (0.057), ankle (0.043), lower back (0.029) and shoulder (0.007), while for spin bowlers the shoulder (0.055) and lower back (0.011) were the primary sites of injury. strategies for the prevention and reduction of lower back injuries in fast bowlers have been undertaken, but there is a need to address shoulder injuries in wrist spinners before it becomes a major concern. the overall incidence of bowling injury was 32.8 injuries per 100 fast bowlers, with bowlers with a workload of <1 000 deliveries showing a lower risk of injury than those with a greater workload. in a study that assessed the risk of injury associated with ground hardness, twomey et al.[15] categorised field hardness as unacceptably hard (>120 gravities (g)), high/normal (90 120 g), preferred range (70 89 g), low/normal (30 69 g) and unacceptably soft (<30 g). grounds rated as having unacceptably high hardness (82%) resulted in 6.5% of the 31 injuries sustained, which included grazes and lacerations sustained when diving to catch the ball. a further 16.1% were possibly related to the ground hardness, indicating either that the low injury rates may be as a result of players changing their behaviour when playing on hard surfaces, i.e. not diving to field or catch the ball, or that ground hardness is a true reflection of the risk of injury, and harder grounds are needed to play cricket.[15] injury surveillance is fundamental for preventing and reducing the risk of injury. however, it is not appropriate to use the data from adult injury surveillance studies to design coaching and training programmes to reduce injuries in young cricketers. therefore, the objective of this study was to expand on the first 3 years of this study[7] in order to understand the seasonal incidence of injuries and injury demographics between elite schoolboy cricketers across player age groups and to make recommendations to protect these young cricketers from injury. method the sample comprised provincial cricketers competing in three national age-group cricket tournaments (u15, u17 and u18) from the 2007 2008, 2008 2009, 2009 2010, 2010 2011 and 2011 2012 seasons, with some players participating in multiple tournaments during that period. ethics approval for this study was obtained from the nelson mandela metropolitan university’s ethics committee. a questionnaire was handed out to all the players by the team coach, and they were required to complete the questionnaire, irrespective of whether an injury had been sustained or not. the questionnaire was designed to obtain the following information for each injury: (i) anatomical site; (ii) month; (iii) cause; (iv) whether it was a recurrence of a previous injury; (v) whether the injury had reoccurred during the season; and (vi) biographical data. no other medical records or records of other sports played were obtained. an injury was defined as an injury that prevented a player from being fully available for selection for a match or which prevented the player from completing the match, with all injuries classified according to the orchard sports injury classification system (osics).[16] injuries were grouped according to the anatomical region injured as follows: (i) head, neck and face; (ii) upper limbs; (iii) back and trunk; and (iv) lower limbs. injuries were classified according to whether they were sustained during batting, bowling, fielding (including catching and wicket-keeping), fitness training and other. the time of the year when the injury occurred was recorded, with off-season being the time of the year when no specific cricket practice or matches took place (april july). the pre-season (august and september) was that sajsm vol. 26 no. 4 2014 125 part of the year when specific cricket training and practice were undertaken in preparation for the season and before the commencement of matches. the season (october march) was defined as the period when matches were played. to allow comparisons to be made between the phases of play during which the injuries were sustained, the number of injuries was expressed as a percentage of the total number of injuries sustained. similarly, to allow comparisons to be made between the injuries sustained by the players in the various age groups, the number of injuries was expressed as a percentage of the number of injuries sustained in that particular age group. all personal and injury data were precoded, double-entered and edited before being transferred to the sample statistical analysis system (sas) to compute univariate statistics and frequency distributions. results the response rate was 57%. of the 2 080 respondents, 712 (34%) were u15, 680 (33%) were u17 and 688 (33%) were u18. of these, 1 508 did not sustain any injury, while the other 572 players sustained 658 injuries, with 497 players sustaining 1 injury, 64 sus tain ing 2 injuries each (128 injuries) and 11 sustaining 3 injuries each (33 injuries) (table 1). of the 658 injuries sustained, similar patterns were found for the three age groups, with the u15 sustaining 239 (36%) injuries, the u17 sustaining 230 (35%) injuries and the u18 groups sustaining 189 (29%) injuries. the injuries occurred primarily during the season (63%) (table 2). new injuries accounted for 27% of the injuries, while 26% were recurrent injuries from the previous season and 47% of the injuries recurred during the same season. the injuries occurred primarily during 1-day matches (30%), practice (29%) or were of gradual onset (21%), with differences for the various age groups. the younger players (u15) sustained more injuries in practice (34%) and less in 1-day matches (24%) than the older players. similar injury patterns occurred for the older (u17 and u18) players, with injuries occurring mostly during 1-day matches. similarly, the u15 players sustained more chronic and less acute injuries than the u17 and u18 groups, which showed similar injury patterns to each other. the u15 players sustained more injuries during the warm-up or playing other sports such as touch rugby, as part of the training session (table 2). the length of time that the players were unable to train or play matches due to injuries showed that 49% of the injuries were lessserious injuries (1 7 days), with injuries of this nature occurring less with increasing age groups (u15: 58%; u17: 45%; u18: 39%). u18 players sustained more serious injuries (33%) than the u17 (29%) and u15 (24%) groups, which resulted in them being unable to practise or play matches for >21 days (table 2). table 1. injuries for the u15, u17 and u18 age groups u15, n (%) u17, n (%) u18, n (%) total, n (%) players 712 (34) 680 (33) 688 (33) 2 080 (100) no injuries 505 (71) 475 (70 528 (77) 1 508 (73) injured 207 (29) 205 (30) 160 (23) 572 (27) injuries sustained 239 (36) 230 (35) 189 (29) 658 (100) 1 injury 180 182 135 497 (76) 2 injuries 44 42 42 128 (19) 3 injuries 15 6 12 33 (5) u = under. table 2. injury occurrence u15 (%) u17 (%) u18 (%) total (%) time of year when injured off-season (april july) 16 14 14 15 preseason (august september) 24 21 20 22 season (october march) 60 65 66 63 occurrence first time 23 30 28 27 recurrent previous season 26 25 28 26 current season 51 45 44 47 injury occurrence warm-up 6 9 3 6 practice 34 26 24 29 20/20 match 4 5 3 4 1-day match 24 34 32 30 gradually 19 21 23 21 other 10 5 15 10 chronicity acute 45 53 51 49 chronic 47 37 39 41 acute-on-chronic 8 10 10 10 time out of cricket (days) 1 3 32 28 22 28 4 7 26 17 17 21 8 14 11 15 18 15 15 21 7 10 10 9 >21 24 29 33 28 u = under. 126 sajsm vol. 26 no. 4 2014 the primary activity leading to injury was bowling (48%), with the runup and delivery the primary mechanisms of injury (table 3). bowling injuries were acute in nature, showing a similar pattern for the three age groups. this was followed by injuries of a chronic nature as a result of over-bowling, with more occurring in the u15 group than the older groups. the second major activity resulting in injury was catching, fielding and throwing (30%), with similar findings for all three age groups. in batting injuries (11%), the primary cause of injury was batting for a long period of time, as well as running between the wickets. the regional distribution of injuries (table 4) showed similar patterns for the age groups, with injuries predominantly to the lower limbs (38%), back and trunk (33%) and upper limbs (26%). lowerlimb injuries were predominantly soft-tissue injuries to muscles (n=119), ligaments (n=44) and tendons (n=29). back and trunk injuries were predominantly muscle (n=78) and stress fracture (n=33) injuries, with the younger players sustaining more stress fractures than the other two groups. the overall injuries were mainly muscle strains (32%), acute sprains (18%) and fractures (15%), which comprised stress (9%) and acute (6%) fractures. discussion the primary finding of this study was that while there are similar findings with regard to bowlers being at the greatest risk of injury and the lower limbs being the most commonly injured site, the injury patterns for schoolboy cricketers differ in a number of areas to those of adult cricketers. the findings of adult studies[1-3] report that bowlers were at the greatest risk of injury (sustaining between 40 and 45% of the injuries), with the primary mechanism of injury being delivery and followthrough (25%). similarly, the primary activity for injury to schoolboy cricketers was bowling (48%), with run-up and delivery the primary mechanisms of injury. the next major activities resulting in injury were to the adult fielders (25 33%) and batsmen (17 21%), with the schoolboys showing similar findings for fielders (30%), but less risk of injury while batting (11%). similar injury patterns were found for the lower limbs (adult 45 49.1%; schoolboy 38%) and upper limbs (adult 23 29%; schoolboy 26%). however, schoolboy cricketers sustained more back and trunk injuries (33%) than the adult cricketers (18.1 23%). while the injuries to adult cricketers were predominantly sustained during matches (52 58%), schoolboy players sustained injuries during 1-day matches (31%), practice (29%) and gradual onset (21%). adult cricketers’ injuries occurred during the first 2 months of the season (35%), while the majority of injuries to schoolboy players occurred throughout the season (63%). the findings show a large difference between the nature of injuries. between 65 and 92% of the adult injuries sustained were new injuries, between 8 and 22% were recurrent injuries from the previous season and 12% recurred in the same season.[1-3] new injuries accounted for 27% of the injuries for schoolboy cricketers, while recurrent injuries accounted for 73% of the injuries: 26% from the previous season and 47% recurring during the same season. the chronicity of the injuries showed a difference between the two groups for acute (adult cricketers 65%; schoolboy cricketers 49%) and chronic (adult cricketers 23%; schoolboy cricketers 41%) injuries, with a similar pattern for injuries of an acute-on-chronic nature (adult cricketers 10%; schoolboy cricketers 10%). schoolboy cricketers sustained more table 3. injury per activity and mechanism u15 u17 u18 total bowling, % 48 45 52 48 run-up and delivery, n 87 81 75 243 overbowling, n 33 23 18 74 fielding, % 29 30 31 30 running to slide and field, n 11 15 11 37 running to catch/field, n 18 14 17 49 impact by ball, n 3 7 3 13 catching ball, n 14 17 8 39 throwing, n 11 13 10 34 batting, % 11 14 9 11 overuse, n 6 11 3 20 running between wickets, n 3 7 5 15 spiked while running, n 2 7 1 10 fitness, % 6 4 5 5 other sports and warmup, n 23 14 15 52 training: running, gym, n 12 3 4 19 other, % 7 7 3 6 u = under. table 4. region distribution of injuries body region u15 u17 u18 total head, % 2 3 3 3 eye, n 2 2 unconscious, n 1 2 3 fracture, n 2 2 3 7 upper limbs, % 26 27 24 26 fracture, n 11 8 6 25 dislocation, n 5 8 6 19 joint, n 10 4 7 21 muscle, n 18 23 11 52 tendon, n 5 4 8 17 ligament, n 4 8 3 15 back and trunk, % 33 34 33 33 stress fracture, n 14 9 10 33 muscle, n 30 28 20 78 lower limbs, % 39 36 40 38 joint, n 14 6 4 24 muscle, n 43 36 40 119 tendon, n 13 9 7 29 ligament, n 16 14 14 44 u = under. sajsm vol. 26 no. 4 2014 127 bowling overuse injuries (11%) than adult cricketers (9%), but fewer batting overuse injuries (3%) than adult cricketers (7%). a closer look at the rate of injury and injury patterns with regard to age reveals further differences. younger u15 players sustained more chronic and less acute injuries than older players, and more injuries in practice than in matches. one of the possible reasons could be that the younger players generally do not play as many matches for their school as the u17 and u18 players. however, whether playing a match or not, they would still attend the same number of weekly practices as the older players. coaches need to be aware of potential risk factors and modify the practice sessions to avoid excessive injuries during practices. however, in order to achieve this, evidence-based research is needed to provide coaches with the necessary guidelines. the rate of injury did not increase with age as previously found in junior club cricketers,[9] which could be as a result of the lower age group of the players represented in the earlier study, as well as the modified nature of the games for these younger players. however, the severity of the injury increased as the age of the players increased, with the younger players sustaining less-serious injuries, u17 players sustaining moderately serious injuries and u18s sustaining moreserious injuries. players and coaches need to be aware of this and adapt their match, practice and training programmes to try to reduce the risk of injury in the various age groups. however, this requires additional research to provide coaches with the necessary guidelines. the findings of the first 3 years of this study[7] show a number of areas that are very similar and which reflect the injury profile staying the same from year to year. these include bowling being the greatest cause of injury, with the majority of injuries being to the lower limbs, and a similar pattern of u18 cricketers sustaining fewer injuries, but of a more serious nature and resulting in being out of cricket for a longer period of time. while recommended guidelines have been established with the view of reducing the risk of injury in young fast bowlers,[17] it would appear that these are not being followed. similar to previous studies on adult cricketers,[1-3] where bowling was the primary cause of overuse injuries, the run-up and delivery were the primary mechanisms of injury in the current study, with a similar pattern for the three age groups. while more overuse injuries occurred in the u15 group than the older groups, the rate of stress fractures increased with the age and level of play for the u15 (8%) to the u17 (10%) and u18 (12%) players. the current study showed similar findings with regard to practice and match injuries as the studies of junior club cricketers[9] and elite senior cricketers.[1-3] however, there was a decrease in injuries in practice as the age and level of play increased, and an increase in match injuries as the age and level of play increased. therefore, it is important that schools, clubs, and players, coaches and parents, continue to monitor the workloads of these young bowlers to ensure that they do not exceed the recommended guidelines. [17] at particular risk are fast bowlers who practise and play for their school during the week, in addition to practising with an adult club team during the week and playing matches for them over the weekend. in addition, young fast bowlers need to use an appropriate technique and be adequately conditioned to deal with the demands of fast bowling. conclusion as in the previous reports on adult cricketers, young cricketers show similar findings with regard to bowlers being at the greatest risk of injury, and the lower limbs being the most commonly injured site. however, there were areas where the injury patterns for schoolboy cricketers differed to those of adult cricketers, with further differences in the injury patterns between the different age groups and level of play. the primary goal of all involved with the administration, coaching, training and playing of cricket at schoolboy level should be to protect young cricketers from injury. here, education is key, particularly with respect to the reduction and prevention of overuse injuries to young fast bowlers. this study is important to key role-players, as it provides details of the effect of practice and matches, role of the player in the team and the mechanism of injury to players at different ages and levels of play. however, further research is required in a number of areas, including providing coaches with evidence-based results that could assist with optimum coaching, training and practice methods to optimise technical and tactical skills while reducing the risk of injury, particularly in younger players who do not play as many matches, but still need to attend practice sessions. finally, the differences in injury patterns between schoolboy and adult cricketers should reinforce that young cricketers are not a smaller version of adult cricketers, and point to a need for different types of practice and match play at different ages and levels of play. references 1. orchard j, james t, alcott e. injuries in australian cricket at first class level 1995/1996 to 2000/2001. br j sports med 2002;36(4):270-275. [http://dx. doi. org/10. 1136/bjsm. 36. 4. 270] 2. leary t, white j. acute injury incidence in professional country club cricketer (19851995). br j sports med 2000;34(2):145-147. [http://dx. doi. org/10. 1136/bjsm. 34. 2. 145] 3. stretch ra, venter djl. cricket injuries: a longitudinal study of the nature of injuries to south african cricketers. south african journal of sports medicine 2005;17(2):4-9. 4. stretch ra. the incidence and nature of injuries in schoolboy cricketers. s afr med j 1995;85(11):1182-1184. 5. millsom nm, barnard jg, stretch ra. seasonal incidence and nature of cricket injuries among elite south african schoolboy cricketers. south african journal of sports medicine 2007;19(3):80-84. 6. noorbhai m h, essack fm, thwala sn, ellapen tj, van heerden jh. prevalance of cricket-related musculosketal pain among adolescent cricketers in kwazulu-natal. south african journal of sports medicine 2012;24(1):3-9. 7. stretch ra, trella c. a three-year investigation into the incidence and nature of cricket injuries in elite south african schoolboy cricketers. south african journal of sports medicine 2012;24(1):10-14. 8. shaw l, finch c. injuries to junior club cricketers: the impact of helmet regulations. br j sports med 2008;42(6):437-440. 9. finch cf, white p, dennis r, twomey d, hayden a. fielders and batters are injured too: a prospective cohort study of injuries in junior club cricketers. j sci med sport 2010;13(5):489-495. [http://dx. doi. org/10. 1016/j. jsams. 2009. 10. 489] 10. walker hl, carr dj, chalmers dj, wilson ca. injury to recreational and professional cricket players: circumstances, type and potential for intervention. accid anal prev 2010;42(6):2094-2098. [http://dx. doi. org/10. 1016/j. aap. 2010. 06. 022] 11. davies r, du randt r, venter djl, stretch ra. cricket: nature and incidence of fastbowling injuries in elite, junior level and associated risk factors. south african journal of sports medicine 2008;20(4):115-118. 12. dennis rj, finch cf, farhart pj. is bowling workload a risk factor for injury to australian junior cricket fast bowlers? br j sports med 2005;39(11):843-846. [http:// dx. doi. org/10. 1136/bjsm. 2005. 018515] 13. gregory pl, batt m, wallace w. comparing injuries of spin bowlers with fast bowlers in young cricketers. clin j sport med 2002;12(2):107-112. 14. gregory pl, batt m, wallace w. is the risk of fast bowling injury in cricketers greatest in those who bowl the most? br j sports med 2004;38(2):125-128. [http://dx. doi. org/10. 1136/bjsm. 2002. 000275] 15. twomey dm, white pe, finch cf. injury risk associated with ground hardness in junior cricket. j sci med sport 2012;15(2):110-115. [http://dx. doi. org/10. 1016/j. jsams. 2011. 08. 005] 16. orchard jw, newman d, stretch r, frost w, manshing a, leious a. methods for injury surveillance in international cricket. j sci med sport 2005;8(1):1-14. [http:// dx. doi. org/10. 1016/s1440-2440(05)80019-2] 17. stretch ra, gray j. fast bowling injury prevention. johannesburg: united cricket board of south africa publication, 1998 40 sajsm vol. 27 no. 2 2015 original research objective. to investigate the difference in performance and bowling opportunity of black african (ba), coloured/indian (c/i) and white (w) cricket bowlers at a junior provincial level in south africa between 2006 and 2012. methods. data of all players performing in the south african interprovincial under-13 (u13), under-15 (u15) and under-19 (u19) tournaments were analysed. bowling performance (bowling average and the top 20 wicket takers relative to their par representation) and bowling opportunity (number of overs bowled) were compared between racial groups. results. there were no significant differences in the bowling averages between ba bowlers and the other racial groups between 2008 and 2012. ba bowling averages were only significantly worse than w bowlers in the u13s in 2006 and u19s in 2007. ba bowling averages were also only significantly worse than c/i in the u13s and u15s in 2007. ba bowlers were below par representation in the top 20 wicket takers in each year for the u15s and u19s and below par representation for the u13s in 2007 2009 and 2011. the performance of c/i and w bowlers was relatively similar across the age groups. ba players bowled significantly fewer overs than w bowlers in the u13s in 2006, in the u15s in 2007 and 2009 and in the u19s in 2006, 2007, 2010 and 2011. c/i bowlers bowled significantly fewer overs than w bowlers in the u13s in 2008 and 2009. conclusion. the bowling averages of the different racial groups are similar. however, there were relatively few ba bowlers in the top 20 wicket takers each year. this could be because of a lack of highly skilled ba bowlers or the lack of opportunity provided to ba bowlers to bowl in these tournaments. s afr j sports med 2015;27(2):40-45. doi:10.7196.570 the cricket bowling performance of different racial groups at a junior provincial level in south africa m s taliep, phd; r gamieldien, btech; s j west, phd department of sports management, faculty of business and management sciences, cape peninsula university of technology, cape town, south africa corresponding author: m s taliep (talieps@cput.ac.za) apartheid in south africa (sa) was a system of legal racial segregation involving political and economic discrimination against black (black african (ba), coloureds/indian (c/i)) south africans. these policies were enforced by the sa government between 1948 and 1994. the apartheid system also disadvantaged blacks in the sporting arena. blacks received minimal and inferior cricket facilities at schools and clubs.[1] an example of this is that a white population of 15%[2] had 89% of the school cricket pitches in 1981.[1] blacks were also not allowed to participate in international sport, thereby further limiting their development. post apartheid (1994), the sa government and the cricketing body in charge at that time, united cricket board of south africa (ucbsa) today known as cricket south africa (csa), were faced with the enormous challenge of trying to redress the injustices caused by apartheid. white (w) players had access to the best fields, facilities, coaches, schools and the provincial and national teams were mainly constituted of w players. the biggest challenge of ubcsa was to develop and transform cricket among the previously disadvantaged black communities so that cricket could be fully represented by all racial groups at all levels. the department of sport in sa defines transformation in the transformation charter as: ‘increased access and opportunities for all south africans, including women, persons with disabilities, youth, children and the elderly to sport and recreation opportunities; the socio-economic benefits of sport are harnessed; and the constitutional right to sport is recognised’.[3] much money was spent on implementing this transformation process.[4] money was spent trying to promote cricket by either building new or upgrading existing facilities. a mini cricket programme was also introduced to develop cricket among the youth at soft cricket ball level. over 2 million children have since been a part of this mini cricket programme.[5] bursaries were established for black players to attend the best cricketing schools in the country.[6] there were a number of programmes and cricket academies introduced to further improve the skill and performance of cricketers. talent acceleration programmes were initiated that targeted the elite u17 and u19 players to prepare them to bridge the gap between junior and senior provincial cricket. the csa high performance programme further aims at developing skilled players. there was the formation of a rural cricket week competition and inland and coastal academies.[7] there is also the csa national cricket academy that aims to bridge the gap between 1st class and international cricket.[7] monitoring the success of transformation is difficult because of its broad definition. despite this broad definition, an important factor to assess the success of the transformation process is to observe the playing numbers and performance of black players at national and provincial level. this is evident in the governmental meetings held where this was discussed.[8-10] some authors have therefore attempted to identify the success of transformation by investigating the playing numbers and performance of black players at senior and junior provincial level. there has been a significant increase in the number of ba players participating in senior provincial cricket but there was a significant decrease at a junior provincial level.[11,12] the increase in c/i players has been at both senior and junior level. sajsm vol. 27 no. 2 2015 41 the performance of senior ba bowlers (runs per dismissal) was on par with w bowlers between 1996 and 2008 (i.e. all years reported by the authors). however, the performance of ba batsmen showed a different trend. they found that there were few skilled senior provincial ba batsmen. senior provincial ba batsmen batting performance, as measured by batting average, was significantly worse than w batsmen for every season between 1996 and 2008. furthermore, at junior provincial level, ba batsmen batting average was significantly worse than w batsmen in every year reported.[12] therefore, there is a concern with the representation and performance of ba batsmen at the junior and senior level, suggesting that the problem exists from a young age and persists to adulthood. despite the numerous development and transformation programmes and policies aimed at enhancing skill, the performance of ba batsmen remained weak. there have been no published articles reporting the bowling performance at a junior provincial level. we are therefore uncertain if ba bowlers are performing well at a junior provincial level (representing a natural ability) or if their performance is weak and then improves as they reach the senior ranks (most probably a representation of the positive effect of development). furthermore, none of the previous studies has investigated the bowling opportunity provided to ba players in matches (i.e. were the bowlers allowed to bowl the same amount of overs as other racial groups). therefore, the aim of the study is to evaluate the performance and bowling opportunity provided to ba bowlers at junior provincial level. methods data were taken from the under-13 (u13), under-15 (u15) and under-19 (u19) annual interprovincial cricket tournaments in sa between 2006 and 2012. bowling performance was determined by two different methods. the first method investigated the bowling average (runs/dismissal) while the second method investigated the number of players in the top 20 highest wicket takers in the tournament relative to their par representation. where more than one player had the same number of wickets, the player with the best bowling average was ranked higher. par representation was determined by calculating the percentage representation of each group relative to their total representation in that year.[12] the following equation was used: par representation (x, y, z) = (total percentage participation × 20)/100. where x, y, z represent w, c/i and ba respectively. the par value was then subtracted from the actual representation of the group in the top 20 and plotted. therefore a value of 1 indicates that a group had 1 person more than the estimated par value for that group, a value of –1 indicates that a group had 1 person less than the estimated par value for that group. opportunity to bowl was measured by the number of overs a player bowled. one-way analysis of variance (anova) was used to determine the difference between the mean bowling averages and mean bowling overs of the different racial groups for each year. when a significant p-level (p<0.05) was achieved, a post hoc, bonferroni test was applied to determined where the means differed. bowling average is a measure of bowling performance, and the higher the average the weaker the performance (i.e. more runs are scored against the bowler before a wicket is taken). results a total of 4 180 players participated in the u13, u15 and u19 interprovincial tournaments between 2006 and 2012. of these 4 180 players, 2 511 (60%) bowled. the number and per cent of ba, c/i and w players that bowled in these tournaments are presented in table 1. although the per cent representation varies in each year, there is relatively equal representation in the u13, u15 and u19 interprovincial tournaments between the w (~50%) and black bowlers (~50%) for each year. there was also similar representation between the c/i (~25%) and ba (~25%) bowlers. bowling performance measures in the u13 age group, there were significant differences in the performance of the three racial groups in 2006 (f2,121=3.6, p=0.030) and 2007 (f2,117=4.9, p=0.009)(table 2). bonferroni (post hoc) comparison of the three groups indicated that in 2006 w bowlers had better bowling averages (mean 22.1, 95% confidence interval (ci) 17.83 26.36) compared with ba bowlers (mean 35.9, 95% ci 22.92 48.96), p=0.034. in 2007 c/i bowlers had significantly better bowling averages (mean 18.5, ci 14.23 22.68) compared with ba bowlers (mean 35.9, 95% ci 23.80 47.05, p=0.008). there was no significant table 1. players participating in the annual interprovincial u13, u15 and u19 tournaments between 2006 and 2012* year ba, % (n) c/i, % (n) w, % (n) total, % (n) u13 2006 27 (34) 21 (26) 52 (64) 100 (124) 2007 22 (26) 26 (31) 53 (62) 101 (120) 2008 23 (28) 22 (27) 56 (69) 101 (124) 2009 22 (29) 26 (34) 52 (68) 100 (131) 2010 25 (29) 26 (30) 50 (58) 101 (117) 2011 23 (30) 27 (36) 50 (66) 100 (132) 2012 15 (20) 33 (45) 52 (71) 100 (136) u15 2006 26 (36) 14 (20) 59 (62) 99 (138) 2007 22 (28) 27 (35) 52 (67) 101 (130) 2008 23 (29) 25 (31) 52 (66) 100 (126) 2009 26 (40) 25 (37) 49 (74) 100 (151) 2010 26 (27) 25 (26) 49 (50) 100 (103) 2011 25 (30) 20 (24) 55 (67) 100 (121) 2012 24 (28) 29 (34) 47 (55) 100 (117) u19 2006 29 (37) 23 (30) 48 (61) 100 (128) 2007 26 (32) 21 (26) 52 (63) 99 (121) 2008 23 (29) 21 (27) 56 (71) 100 (127) 2009 24 (33) 26 (35) 50 (67) 100 (135) 2010 22 (25) 27 (31) 51 (58) 100 (114) 2011 24 (31) 29 (37) 46 (59) 99 (127) 2012 31 (39) 20 (25) 49 (61) 100 (125) *owing to rounding off the values may not equal 100%. 42 sajsm vol. 27 no. 2 2015 difference between w and c/i bowlers in 2006 and 2007. there were no significant differences in the bowling averages between racial groups from 2008 to 2012. in the u15 age group, there were only significant differences in the performance of the three racial groups in 2007 (f2,126=4.6, p=0.012) (table 3). post hoc comparison of the three groups indicated c/i bowlers had significantly better bowling averages (mean 19.2, 95% ci 15.53 22.82) compared with ba bowlers (mean 31.3, 95% ci 22.92 39.66, p=0.009). there was no significant difference between w and c/i bowlers in 2007. there were no significant differences in the bowling averages between racial groups for 2006 and between 2008 and 2012. in the u19 age group, there were only significant differences in the performance of the three racial groups in 2007 (f2,118=4.9, p=0.009) (table 4). post hoc comparison of the three groups indicates that w bowlers had significantly better bowling averages (mean 29.7, 95% ci 18.87 31.02) compared with ba bowlers (mean 48.6, 95% ci 17.81 35.33, p=0.007). there were no significant differences in the bowling averages between the groups for 2006 and between 2008 and 2012. data of the top 20 highest wicket takers relative to their par representation are presented in fig. 1. ba bowlers were below par representation for the u13s from 2007 to 2009 and in 2011. in the u13 group, w bowlers were mainly above par representation (2006, 2008, 2009, 2011, 2012) while the c/i bowlers oscillated above and below the par representation mark. in the u15 group, ba bowlers were below the par representation mark in every year while w bowlers generally appear above the par representation mark (2007 2012). c/i bowlers oscillated above and below the par representation mark. in the u19 age group, ba bowlers were below the par representation mark in every year. c/i bowlers are above the par representation level for the u19s from 2006 to 2009 and in 2011, while w bowlers approximated the par representation mark. opportunity to bowl in the u13 age group, there were significant differences in the mean bowling overs of the three racial groups in 2007 (f2,117=4.7, p=0.01), 2008 (f2,121=6.8, p=0.002) and 2009 (f2,128=3.9, p=0.022)(table 5). post hoc comparison of the three groups indicates that in 2007 w bowlers bowled significantly more overs (mean 26.7, 95% ci 23.8 29.6) than ba bowlers (mean 18.5, 95% ci 14.6 22.3, p=0.008). white bowlers also bowled significantly more overs than c/i in 2008 (mean 32.6, 95%ci 29.0 36.3 v. mean 25.5, 95% ci 20.7 30.3) and in 2009 (mean 28.4, 95% ci 24.8 32.1 v. mean 19.9, 95% ci 16.0 23.8). in the u15 age group, there were significant differences in the mean bowling overs of the three racial groups in 2007 (f2,127=3.5, p=0.033) and 2010 (f2,100=3.7, p=0.029)(table 6). post hoc comparison of the three groups indicated that w bowlers bowled significantly more overs than ba in both 2007 (mean 24.8, 95% ci 22.2 27.5 v. mean 18.5, 95% ci 14.9 22.2, p=0.031) and in 2010 (mean 20.6, 95% ci 17.1 24.1 v. mean 13.5, 95% ci 10.7 16.3, p=0.025). in the u19 age group, there were significant differences in the mean bowling overs of table 2. a comparison of the u13 bowling averages of the different racial groups between 2006 and 2012 u13 ba, mean (sd) c/i, mean (sd) w, mean (sd) f-value p-value 2006 35.9 (37.3)* 31.3 (23.1) 22.1 (17.1)* 3.6 0.030* 2007 35.4 (28.8)* 18.5 (11.5)* 24.0 (20.3) 4.9 0.009* 2008 22.0 (16.8) 31.9 (21.4) 26.3 (24.2) 1.4 0.255 2009 25.7 (23.3) 16.9 (8.3) 24.4 (18.2) 2.6 0.079 2010 22.1 (13.9) 17.5 (9.8) 20.5 (15.5) 0.9 0.429 2011 25.0 (15.0) 24.2 (26.0) 25.5 (18.1) 0.1 0.951 2012 25.6 (18.4) 23.2 (15.9) 22.0 (15.3) 0.4 0.667 sd = standard deviation. * significant difference, p<0.05. table 3. a comparison of the u15 bowling averages of the different racial groups between 2006 and 2012 u15 ba, mean (sd) c/i, mean (sd) w, mean (sd) f-value p-value 2006 29.7 (18.6) 23.4 (15.5) 27.0 (18.2) 0.8 0.447 2007 31.3 (21.6)* 19.2 (10.6)* 23.6 (15.3) 4.6 0.012* 2008 27.5 (18.6) 28.8 (16.5) 23.1 (12.9) 1.8 0.171 2009 25.1 (16.5) 27.8 (19.0) 26.0 (19.9) 0.2 0.847 2010 27.0 (19.6) 22.9 (12.6) 21.2 (11.2) 0.5 0.595 2011 22.1 (14.8) 27.5 (19.3) 26.9 (20.0) 0.8 0.453 2012 16.4 (8.5) 18.9 (14.4) 22.5 (20.3) 1.4 0.261 * significant difference, p<0.05. table 4. a comparison of the u19 bowling averages of the different racial groups between 2006 and 2012 u19 ba, mean (sd) c/i, mean (sd) w, mean (sd) f-value p-value 2006 34.7 (18.6) 25.3 (14.0) 28.0 (17.5) 2.8 0.062 2007 48.6 (36.8)* 33.5 (27.0) 29.7 (23.2)* 4.9 0.009* 2008 36.0 (23.5) 28.1 (18.8) 28.1 (20.8) 1.6 0.210 2009 26.6 (22.6) 31.4 (23.9) 26.4 (23.8) 0.5 0.587 2010 31.6 (21.5) 24.0 (19.7) 29.0 (16.6) 1.3 0.286 2011 27.4 (17.3) 23.4 (17.4) 22.4 (14.1) 1.0 0.357 2012 30.9 (21.2) 25.4 (13.2) 28.8 (20.2) 0.6 0.547 * significant difference, p<0.05. sajsm vol. 27 no. 2 2015 43 the three racial groups in 2006 (f2,125=5.2, p=0.007), 2007 (f2,118=3.1, p=0.049), 2010 (f2,111=4.9, p=0.009) and 2011 (f2,124=5.0, p=0.009)(table 7). post hoc comparison of the three groups indicates that c/is bowled significantly more overs than bas in 2006 (mean 28.7, 95% ci 24.2 33.3 v. mean 20.2, 95% ci 16.8 23.7), p=0.007 and in 2010 (mean 27.4, 95% ci 22.1 28.3 v. mean 18.3, 95% ci 14.6 22.1, p=0.012). white bowlers bowled significantly more overs than ba in 2007 (mean 25.3, 95% ci 22.6 28.0 v. mean 19.6, 95% ci 16.5 22.8, p=0.043), 2010 (mean 25.6, 95% ci 22.8 28.3 v. mean 18.3, 95% ci 14.6 22.1, p=0.028) and 2011 (mean 29.3, 95% ci 25.6 33.1 v. mean 19.9, 95% ci 16.6 23.2, p=0.007). discussion in the u13, u15 and u19 provincial teams, there was relativly equal representation of black (ba & c/i, ~50%) and w bowlers (~50%) between 2006 and 2012. there was also relatively similar representation between the c/i and ba bowlers. unfortunately, it is very difficult to determine if all the players were selected purely on merit as the transformation target system stipulated a minimum of 50% representation of black players per team. to better assess this system, it is therefore important to investigate the bowling performance of these players during the tournament. the bowling performances were assessed using two separate methods. the first investigated the bowling average of all players in the tournament, which provided an indication of the performance of the ba bowlers as a group. during 2006 and 2007 there were some significant differences between ba and the other racial groups, where ba bowling performances were worse. however, between 2008 and 2012 there were no differences in the bowling performance between ba bowlers and other racial groups. this suggests an improvement in the performances of ba players relative to the other racial groups. a reason for this could be the numerous development programmes and transformation policies implemented by csa aimed at improving the status of cricket among black cricketers. these results are similar to the bowling performances at senior provincial cricket, where there were no significant differences between the bowling averages across races over an 2006 2007 2008 2009 2010 2011 2012 2006 2007 2008 2009 2010 2011 2012 2006 2007 2008 2009 2010 2011 2012 10 5 0 –5 –10 10 0 –5 5 –10 10 0 –5 5 u13 u15 u19 year black african coloured/indian white n o. o f p la ye rs in th e to p 2 0 (w ic ke t t ak er s) re la tiv e to p ar re p re se nt at io n n o. o f p la ye rs in th e to p 2 0 (w ic ke t t ak er s) re la tiv e to p ar re p re se nt at io n n o. o f p la ye rs in th e to p 2 0 (w ic ke t t ak er s) re la tiv e to p ar re p re se nt at io n fig. 1. a representation of the number of players in the top 20 wicket takers relative to par representation for each year. table 5. a comparison of the mean number of overs bowled between the different racial groups for the u13s between 2006 and 2012 u13 ba, mean (sd) c/i, mean (sd) w, mean (sd) f-value p-value 2006 24.3 (11.7) 20.8 (13.4) 25.7 (11.9) 1.5 0.227 2007 18.5 (9.5)* 24.8 (12.9) 26.7 (11.5)* 4.7 0.01* 2008 28.6 (15.1) 25.5 (14.5)* 32.6 (15.1)* 6.8 0.002* 2009 26.3 (16.5) 19.9 (11.1)* 28.4 (15.1)* 3.9 0.022* 2010 22.5 (11.5) 23.0 (13.9) 23.6 (10.7) 0.1 0.903 2011 21.2 (12.8) 22.6 (12.7) 27.3 (13.8) 2.1 0.122 2012 20.9 (13.1) 22.6 (13.3) 28.0 (15.9) 2.9 0.059 * significant difference, p<0.05. 44 sajsm vol. 27 no. 2 2015 8-year period.[11] from these data, we are tempted to conclude that the performances of ba bowlers are on par with the other racial groups at both a junior and senior level. however, one has to investigate the best bowlers in the tournament to provide an indication of bowling excellence. the second method of investigating bowling performances was to report the proportion of bowlers in the top 20 (highest wickets taken). ba bowlers were consistently below the par representation mark in all years for the u15s and u19s, while often occurring below the par representation mark in the u13 age group. the ba bowlers were never above the par representation mark for any of the age groups. there are three possible reasons for this. the first is that there are a number of good ba bowlers participating in the provincial tournaments but few exceptional bowlers. as a result there are relatively fewer bowlers in the top 20. the second reason could be related to the fact that they have been given fewer opportunities to bowl. w bowlers, for example, generally bowled more overs in the tournaments in each age group. the bowling average data indicate that there were few differences between the racial groups yet w bowlers bowled more overs than ba bowlers. w bowlers’ mean bowling averages were only significantly better than ba bowlers in 2006 in the u13 group and in 2007 in the u19 group. however, w bowlers were allowed to bowl significantly more overs than ba in 2007 in the u13, 2007 and 2010 in the u15 and 2007, 2008 and 2011 in the u19 group. ba bowlers therefore have less opportunity to take wickets and this could hinder their ability to be in the top 20 wicket takers in the tournament. the third possibility is that ba bowlers are given a chance to bowl a few overs very late in the innings. they then bowl to batsmen that are weaker (tail enders) and easier to dismiss. this could possibly explain why their bowling averages are similar yet they take fewer wickets. however, this is speculative as the information on bowling order is not available. one of the main aims of csa is to provide equal opportunity for all cricketers to achieve the highest level of success in the sport.[9] they therefore introduced the target policy. this policy specifies a target of a certain number of black players in provincial and national teams at senior and junior level. committees were established to monitor the implementation of this transformation policy.[13] however, the target system becomes ineffective if ba players of equal skill are not provided with the same opportunities in matches. ba cricketers have voiced their concerns regarding this lack of opportunity.[14] in a study done by bayer,[14] 20 ba cricketers in the gauteng province of sa were interviewed. it was found that 65% of these players believed that w cricketers were given better opportunities. the author reported that this perceived lack of opportunity created a feeling of despair among the ba players. interestingly, in sa rugby at an international level, bas had less playing time than other players,[15] suggesting a trend of providing less opportunity to ba players during matches. the possibility of racial prejudice in sa sport needs to be considered as this will in turn counteract the pur pose of the development and transformation system. despite the lack of opportunity provided to ba bowlers at a junior provincial level in sa, they still appear to be competent at bowling. this implies merit selection of bowlers, counteracting the idea of ‘window dressing’ and credit should be given to csa for achieving this. these data drastically contrast with the batting average data where ba batting averages were worse than w batsmen for every year for both u15s and u19s. the poor performance of ba batsmen at a junior level continues to the senior ranks. therefore, it can be suggested that the lag in development is too great in batting so that the ba players are not able to catch up. lambert[16] has expressed concern that if athletic development does not take place within specific windows of opportunity, the athlete might not be able to catch up later in their career. with the introduction of the long-term athletic development model by csa[17] the focus is on general movement and sports skills development at an early age.[18] less technical coaching is required at this young age (below 13 years)18 and the child’s natural flair and skill largely contributes to their success as a cricketer. as the child reaches adolescence and enters secondary school, there is a greater requirement for sports specific skills to be enhanced.[18] the reliance on a coach, parents and good table 6. a comparison of the mean number of overs bowled between the different racial groups for the u15s between 2006 and 2012 u15 ba, mean (sd) c/i, mean (sd) w, mean (sd) f-value p-value 2006 21.2 (11.7) 27.6 (12.7) 23.4 (10.7) 2.1 0.125 2007 18.5 (9.5)* 21.9 (11.7) 24.8 (10.8)* 3.5 0.033* 2008 22.9 (13.8) 26.5 (13.2) 29.1 (12.7) 2.2 0.111 2009 16.1 (8.2) 21.0 (12.5) 21.3 (11.5) 2.8 0.067 2010 13.5 (7.1)* 18.9 (11.8) 20.6 (12.4)* 3.7 0.029* 2011 23.9 (14.7) 26.9 (14.7) 28.8 (15.5) 1.1 0.347 2012 18.9 (10.2) 22.7 (11.4) 22.8 (10.7) 1.3 0.271 * significant difference, p<0.05. table 7. a comparison of the mean number of overs bowled between the different racial groups for the u19s between 2006 and 2012 u19 ba, mean (sd) c/i, mean (sd) w, mean (sd) f-value p-value 2006 20.2 (10.4)* 28.7 (12.2)* 25.8 (11.1) 5.2 0.007* 2007 19.6 (8.7)* 22.9 (12.3) 25.3 (10.6)* 3.1 0.049* 2008 24.7 (15.1) 31.8 (16.8) 31.4 (16.8) 1.9 0.151 2009 21.0 (11.0) 24.7 (12.9) 26.1 (11.8) 1.7 0.194 2010 18.3 (9.0)*,† 27.4 (14.3)† 25.6 (10.5)* 4.8 0.009* 2011 19.9 (9.0)* 27.3 (15.3) 29.3 (14.5)* 5.0 0.009* 2012 26.2 (12.2) 29.9 (14.5) 30.6 (12.9) 1.5 0.237 * significant difference, p<0.05. † significant difference, p<0.05. sajsm vol. 27 no. 2 2015 45 facilities are important during this phase of skills development. this early adolescence phase might be an important window of trainability for skill acquisition in batting but not for bowling. bas were the worst disadvantaged group during apartheid. they did not have access to the best cricketing schools, coaches, training programmes and facilities. these important components, if missed during adolescence could have adverse effects on the development of the batsmen. this could explain the reason for the poor batting performance of ba players from the junior (u15 and u19) and through the senior ranks. this hypothesis is supported by the fact that in the current sa national team, all specialist batsmen have attended good cricketing schools in sa. these schools are renowned for their culture of cricket, coaches and cricketing excellence. in contrast, the bowlers of the sa team did not necessarily attend this type of school. dale steyn, morné morkel and vernon philander are good examples. in addition, many world class international bowlers only started bowling at a late age. these include bowlers like wes hall, curtley ambrose, dirk nannes and zaahir khan.[19-24] it has been reported that ambrose only started playing formal cricket at the age of 21.[22] on the contrary, it is almost unheard of for skilled international batsmen to have developed or started playing at such a late age. if ba bowlers were provided with the appropriate support, opportunities and coaching, they are likely to improve their bowling performances even further and could become among the best bowlers in the country. acknowledgements. the authors would like to thank all the coaches and coaching managers of the various provinces for their assistance with the classification of players and to mrs corrie uys for her assistance with the statistics. references 1. human sciences research council. investigation into education (south africa). report of the main committee. pretoria: human science research council, 1981. 2. spain d. republic of south africa: unraveling the population size. country profile. int demogr 1984;3(6):4-11. 3. sport and recreation south 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[http://dx.doi.org/10.1080/0031322042000250457] 7. cricket south africa. csa national cricket academy, 2014. http://www.cricket.co.za/ development_programs.aspx?id=14 (accessed 2 september 2014). 8. parliamentary monitoring group. sa cricket selection: selectors meeting with cricket south africa minutes, 2007. http://db3sqepoi5n3s.cloudfront.net/files/ docs/080226minutes.htm (accessed 1 september 2014). 9. parliamentary monitoring group. cricket sa: transformation policy: selection of national cricket team. transformation background, 2008. http://www.pmg.org.za/ files/docs/080226csa.pdf (accessed 1 september 2014). 10. parliamentary monitoring group. cricket south africa on transformation plan, disciplinary process with mr majola, 2012. http://www.pmg.org.za/report/20120801-briefing-cricketsouth-africa-transformation-plan-implementation-spor (accessed 1 september 2014). 11. taliep ms. effectiveness of the cricket transformation process in increasing representation and performance of black cricketers at provincial level in south africa. s afr j sports med 2009;21(4):156-162. 12. taliep ms, gamieldien r, west s. an analysis of the performance of black african junior provincial cricket batsmen. s afr j sports med 2011;23(3):90-94. 13. vahed g, padayachee v, desai a. between black and white: a case study of kwazulunatal cricket union. in: desai a, ed. the race to transform sport in post-apartheid sa. cape town: hsrc press, 2010:222-256. 14. bayer j. a phenomenological study of a sample of young black players in the transformation process of cricket in gauteng. ma thesis. kwadlangezwa: university of zululand, 2010. 15. du toit j, durant j, joshua j, lambert m. playing time between senior rugby players of different ethnic groups across all levels of south african rugby. s afr j sports med 2012;24(3):81-86. [http://dx.doi.org/10.7196/sajsm.327] 16. lambert m. the lack of transformation in sport and the long-term athletic development programme. s afr j sports med 2010;22(3):54. 17. cricket south africa. long-term participation development programme: from grassroots to proteas, 2011. http://www.cricket.co.za/docs/coaching/ltpd%20 nov%202011.pdf (accessed 1 september 2014). 18. balyi i, way r, higgs c. long term athletic development. united states: human kinetics, 2013. 19. national sporting archives of trinidad and tobago. wesley windfield hall. http:// www.sportarchivestt.com/athletes/wesley-winfield-hall/ (accessed 2 september 2014). 20. sports pundit. wes hall. http://www.sportspundit.com/cricket/cricketers/9290-weshall (accessed 2 september 2014). 21. journalism of courage archive. curtly ambrose, a reluctant cricketer who became a legend. http://archive.indianexpress.com/news/curtly-ambrose-a-reluctant-cricketerwho-became-a-legend/802820/0 (accessed 2 september 2014). 22. ambrose c. curtley elconn lynwall ambrose. http://curtlyambrose.com/biography. php (accessed 2 september 2014). 23. danakar s. interview/zahier khan. sportstar 2002;25(44):2-8. http://www. sportstaronnet.com/tss2544/25440160.htm (accessed 4 september 2014). 24. nrc.nl. skier turned cricket player boost dutch success. 2009. http://vorige.nrc.nl/ international/features/article2265622.ece (accessed 4 september 2014). sajsm 535.indd original research sajsm vol. 26 no. 4 2014 99 background. therapeutic ultrasound (us) is an electrophysical therapy that is commonly used by sports physiotherapists, but its mechanism of action is unclear. there is little evidence that us therapy is more effective than sham us therapy, and any clinical benefits may be due to a placebo effect. objective. to investigate whether us has a specific effect that renders it effective in its own right, or whether its effect is placebo driven. methods. in a double-blind controlled trial, delayed-onset muscle soreness (doms) was experimentally induced in both bicep muscles of 15 females. sham us was applied to one bicep (n=15 biceps) and pulsed active us to the other bicep (n=15 biceps) of each participant, 48 and 72 h after induction of doms. primary and secondary outcomes were pain reported on the mcgill pain questionnaire (mpq) and range of movement (rom) (elbow extension) measured by goniometry, respectively. results. results showed significant improvements in pain and rom over the intervention periods, but there was no difference between interventions. conclusion. us and sham us therapy improve pain equally when treating doms of the biceps in the context of a therapeutic encounter. this analgesic effect is placebo driven. clinicians can influence the analgesic effect of us by managing the therapeutic context. management of patients’ anxiety may also boost the analgesic effect of us. s afr j sm 2014;26(4):99-103. doi:10.7196/sajsm.535 ultrasound v. sham ultrasound for experimentally induced delayedonset muscle soreness: a double-blind, randomised controlled trial r parker,1 phd (psych); v j madden,2 bsc (phys) 1 department of health and rehabilitation sciences, faculty of health sciences, university of cape town, south africa 2 sansom institute for health research, university of south australia, adelaide, australia corresponding author: r parker (romy.parker@uct.ac.za) therapeutic ultrasound (us) is an electrophysical t h e r apy t h at i s c om m on l y u s e d by s p or t s physiotherapists, but its mechanism of action is unclear.[1] there is little evidence that us therapy is more effective than sham us therapy, and any clinical benefits may be due to a placebo effect.[2] the term ‘placebo effect’ is used when a treatment that is known to have no specific physiological efficacy produces a positive therapeutic outcome. it is heavily reliant on the context of treatment and on the patient’s expectation of benefit.[3] physiotherapists enhance placebo value by using positive therapeutic relationships and educating their patients about the anticipated effects of treatment.[4] delayed-onset muscle soreness (doms) is pain or discomfort that develops in muscles after exercise that is unfamiliar.[5] doms is self-limiting and easily induced experimental setting. clinical findings include muscular tenderness and loss of range of movement (rom), flexibility and strength. symptoms develop gradually and peak after 24 48 h, resolving within 72 h.[6] the efficacy of us in treatment of doms has been investigated by a few studies of poor methodological quality.[2] methods this study investigated the effect of us in the treatment of doms, and was designed to explore whether us has a specific effect, or whether it works via a placebo effect. a double-blind controlled trial was designed to compare the effects of active us v. sham us on the symptoms of experimentally induced doms of the biceps muscle group. the primary outcome was pain, measured by the mcgill pain questionnaire (mpq);[7] the secondary outcome was elbow rom, measured with a goniometer.[8] the study was conducted in accordance with the declaration of helsinki and approved by the institutional research ethics committee. participants and setting healthy female physiotherapy students at the university of cape town were invited to participate. exclusion criteria were preexisting medical conditions for which us is contraindicated, preexisting upper limb discomfort or injury, prior experience of us treatment for doms or altered test results for skin hot/cold or sharp/ blunt sensations. twenty undergraduate students, aged 18 25 years, volunteered. participants were given an information sheet listing the symptoms of doms and the study procedures, and then given an opportunity to ask further questions before agreeing to participate. participants were asked not to take pain medication, perform any strenuous exercise or change their diets during the course of the study. at the end of the study, participants were given information sheets detailing interventions that might help to clear remaining symptoms. interventions and data collection were conducted at the physiotherapy practical teaching venue of the university of cape town. outcome measures the outcome measures were pain and elbow rom. pain was assessed using the mpq, which has shown good validity and reliability in doms-related pain[9] after translation and across cultures.[7] elbow rom was measured using standardised goniometry, also shown to be valid and reliable by numerous authors. [9] goniometry was 100 sajsm vol. 26 no. 4 2014 performed while participants sat with the upper arm supported. the goniometer’s stationar y arm was aligned with the longitudinal axis of the humerus and the moving arm with the longitudinal axis of the forearm. one researcher (assistant a) took all measurements. pilot study a pilot study was performed to standardise the methods of doms induction and data collection. in the pilot study, an i-kon1011 (chattanooga ltd, usa) isokinetic machine was used to induce doms, but this was found to be ineffective. it was replaced by the following eccentric exercise protocol described by stay.[10] participants performed concentric and eccentric bicep curls using a dumbbell. participants performed four sets of 10 repetitions (or to muscle failure) at 80% of their one-repetition maximum (1rm). this was followed by four sets of 10 repetitions (or to muscle failure) of eccentric contractions at 100% of their 1rm. during the eccentric contraction, participants were instructed to slowly lower the dumbbell from full elbow flexion to full extension over 5 s, with assistant c returning the weight to the starting position. participants rested for 1 min between each set. with the new protocol, pilot participants reported maximal symptoms 48 h after exercise. procedure the experimental procedure is illustrated in fig. 1. baseline data collection (t0) baseline measures of pain and elbow rom were recorded for both biceps (left and right) of each participant before doms was induced (t0). induction of doms (t0) before doms was induced, a researcher read a prepared script to the participants to remind them of the symptoms of doms. participants were then asked to perform bilateral, resisted concentric and eccentric bicep curls according to the protocol previously described.[10] following this exercise bout, participants were asked to return for us treatment at 48 and 72 h. ultrasound (t48 and t72) us sonoplus 190 machines were calibrated and used with an appropriate coupling gel. the same two researchers (assistants b and c) administered all us interventions. at 48 h (t48), a script explaining the upcoming procedure was read to the participants. pain and rom were measured by assistant a. machine a delivered active us at 1 mhz, 0.4 w/cm2, pulsed 1:4, for 7 min. machine b delivered a sham dose (intensity set to 0 w/ cm2) for the same time period. assistant d set up the us machines behind a screen and all instrumentation was covered so that the researchers operating the us machines and all participants were blinded as to which machine delivered which dose. assignment of machine to biceps was quasi-random. assistant e allocated the first participant’s right arm to one intervention by coin toss, and subsequent participants’ arm allocations were alternated. both arms were treated concurrently (one with machine b and one with machine a). the same two researchers administered treatment with the same machines at 48 (t48) and 72 h (t72). this consistency was maintained to standardise treatment and minimise bias. data collection pain and rom were re-assessed before and after each intervention session by a single researcher (assistant a), who was blinded as to which arm received active or sham treatment. statistical analysis a 30% reduction in pain was considered clinically significant.[11] a power calculation with p<0.05 suggested a sample of 15 participants (n=15 biceps per group) to detect this change, with a power of 0.86. data were recorded using microsoft excel (2003) and analysed using spss statistics version 21 (ibm, usa). kolmogorov-smirnov tests found that the data were normally distributed. repeated measures analyses of variance (anova) with a priori comparisons were used, for both outcomes, to compare each time point with the preceding one. statistical significance was set at p<0.05. results were presented using means and standard deviations. mauchly’s test was used to assess the assumption of sphericity. where sphericity was violated, degrees of freedom were corrected using the greenhouse-geisser estimates of sphericity and the corrected value was reported. results demographics twenty female students volunteered for the study. one was excluded because of recently doms induced intervention 1 intervention 2 t48 t49 t72 t73t0 time (h) fig. 1. the experimental procedure. (doms = delayed-onset muscle soreness.) 20 volunteers recruited doms induced allocated to active us – received intervention 15 participants remaining (n=30 biceps) – analgesic use (n=2) – diabetes (n=1) – inadequate induction of doms (n=2) excluded (n=1) excluded (n=4) – analysed (n=15 biceps) allocated to sham us – received intervention – analysed (n=15 biceps) fig. 2. breakdown and allocation of research volunteers. (doms = delayed-onset muscle soreness; us = ultrasound.) sajsm vol. 26 no. 4 2014 101 diagnosed diabetes. two participants were excluded because doms was not adequately induced (they had no pain or loss of rom 48 h aft er the exercise bout), and a further two for using analgesics. th e fi nal sample comprised 15 participants: 15 biceps in the experimental group and 15 in the control group (fig. 2). eff ect of us v. sham us on doms symptoms th e changes in pain over time are shown in fig. 3. repeated measures 2 (intervention: active or sham us) × 4 (t48, t49, t72, t73) anova showed that the type of intervention had no eff ect on pain (p=0.884). however, pain diff ered over time (f(1.68, 23.53.)=6.94; p=0.006). contrasts showed that pain decreased significantly from t48 to t49 (f(1, 14)=7.35; p=0.017), and from t72 to t73 (f(1, 14)=12.27; p=0.004), revealing that the two interventions were equally effective on both treatment occasions. contrasts also showed that pain did not change between interventions from t49 to t72 (p=0.59). th ere was no interaction eff ect between intervention and time. th e changes in rom over time are shown in fig. 4. repeated measures 2 (intervention) × 5 (t0, t48, t49, t72, t73) anova showed that the type of intervention had no eff ect on rom (p=0.198). however, rom did change over time (f(2.32, 32.52)=18.91; p=0.0001). contrasts showed that rom diminished from baseline to t48 (f(1, 14)=87.68; p=0.0001), and then increased over the fi rst intervention period from t48 to t49 (f(1, 14)=11.32; p=0.005). rom did not change over the second intervention period (p=0.09), or between interventions (p=0.67). there was significant interaction eff ect (f(4, 56)=2.91; p=0.030). contrasts for this interaction were marginally signifi cant at one level: t49 v. t72 (f(1, 14)=4.66; p=0.049). over this time period, rom decreased in the active us group and increased in the sham us group. discussion natural history or placebo eff ect? this study used a double-blinded, withinsubject design to investigate the effi cacy of sham v. active us interventions for decreasing pain related to d oms of the biceps. participants received each intervention twice: at 48 h and 72 h aft er induction of doms. participants reported decreased pain immediately aft er intervention (t48 t49 and t72 t73), regardless of whether active or sham us was used. in contrast, participants did not report decreased pain over the 23 h between interventions (t49 t72), showing that changes in pain over the intervention periods cannot be attributed to spontaneous time (h) to ta l e lb o w r o m (º ) intervention sham us active us t 49 t 72t48 t73t0 100 110 120 130 140 150 160 fig. 4. changes in elbow rom over time. (rom = range of movement; us = ultrasound.) fig. 3. changes in pain over time. (us = ultrasound.) t 49 t 72 t 48 t 73 0 2 4 6 8 10 12 intervention sham us active us time (h) pa in o n m cg ill p ai n q u es ti o n n ai re 102 sajsm vol. 26 no. 4 2014 resolution of doms. these results indicate that active and sham us treatments were both equally effective in reducing pain. changes in rom were also unaffected by the nature of the intervention. participants showed a loss of rom over the first 48 h, to be expected after the induction of doms. they showed a recovery of some rom during the first intervention and no significant changes thereafter, suggesting that the two interventions were equally effective 48 h after doms induction. these results also revealed a statistically significant difference in recovery pattern between shamand active-treated groups between interventions (t49 t72), but the difference was too small to be clinically relevant. the comparable efficacy of active us and sham us for decreasing pain and improving rom when applied to opposite arms of the same participant suggests a mechanism that is systemic rather than local. other studies demonstrating a strong placebo effect of us our results corroborate those of hashish et al.,[12] who found sham us to have comparable or better effects than active us for pain and inflammation. in fact, the efficacy of us for musculoskeletal disorders has been reviewed and subjected to meta-analysis.[13] again, the results indicated that active us is not appreciably superior to sham us in multiple indicators of recovery, including pain and swelling. however, the findings are not entirely unequivocal: some studies still contradict this idea. two out of ten papers reviewed by robertson et al.[2] showed that active us was more beneficial than sham us for the treatment of soft-tissue injuries; however, only one of these two studies used pain as an outcome. the available evidence suggests that any positive therapeutic effect of us treatment for pain lies in its placebo value. how placebos cause analgesia the placebo effect is driven by both opioid and non-opioid mechanisms.[14] when a subject anticipates that pain will be relieved, the endogenous opioid system is activated, causing a powerful analgesic effect. this effect can be blocked by naloxone.[3] the placebo effect can also be induced by classic conditioning when pain reduction is not expected: a conditioned response is first set up by repeated administration of an inert substance together with an exogenous opioid. after this administration, the inert substance alone will induce analgesia.[3] this conditioned response is only partly blocked by naloxone, indicating that it works via a non-opioid mechanism.[3] t h e o p i o i d d r i v e n c o mp o n e nt o f placebo analgesia acts via descending painmodulating pathways, involving the rostral anterior cingulate cortex, orbitofrontal cortex, peri-aqueductal grey matter, pons and medulla.[15] these pathways use opioids to increase inhibition at the dorsal horn of the spinal cord. this reduces the amount of nociceptive signal reaching the brain. endogenous opioids also seem to reduce inflammatory pain in peripheral tissues. cholecystokinin (cck) antagonises this entire opioid-mediated process, which corresponds with cck’s known role in states of anxiety: cck may increase pain when subjects anticipate negative outcomes.[3] the anticipation that underpins opioiddriven placebo analgesia is thought to depend heavily on psychosocial context. the presence of a therapist, the ritual of giving a treatment and the visible presence of therapeutic equipment may influence it.[3] us fits this model: it is a ‘hands-on’ therapy that requires a therapist to be actively involved throughout the treatment. in this study, us was delivered for 7 min with the us transducer head visible to the participants. the information sheet was read to participants before the intervention to reduce expectations regarding the efficacy of us therapy (‘ultrasound is an electrotherapy modality that is commonly used by physiotherapists during treatment sessions. however, there is limited evidence to support its effectiveness in the treatment of doms. in this study, the effectiveness of a non-thermal dose of ultrasound on doms will be investigated with the aim of increasing the evidence base for the therapeutic use of ultrasound’), but in other respects the psychosocial context was typical of a therapeutic situation. the presence of a therapist and provision of apparent therapy may be enough to overrule a neutral information sheet, thus creating an overall expectation of improvement. further expectation may have been generated by the fact that the participants in the study were physiotherapy students who had been trained to use us. although their education and training included critical, evidence-based material on the efficacy of us, simply including the modality in the curriculum may have engendered a belief that it works. anticipation of a positive outcome would cause an opioiddriven placebo response and reduce pain.[16] implications for practice the ethical considerations arising from studies such as this one have caused some controversy. is it acceptable to prescribe placebo treatments to patients? the benefits of placebo-induced analgesia have been well documented,[14] so the conflict revolves table 1. pain reported on the mpq, by intervention active us arms, mean (sd) sham us arms, mean (sd) t48 6.73 (3.52) 7.40 (6.00) t49 5.47 (3.16) 5.40 (5.38) t72 5.13 (5.03) 4.53 (4.09) t73 3.40 (2.97) 2.80 (3.08) mpq = mcgill pain questionnaire; us = ultrasound; sd = standard deviation. table 2. rom, by intervention active us arms, mean (sd) sham us arms, mean (sd) baseline 145.27 (5.80) 144.40 (6.00) t48 132.87 (9.42) 135.33 (6.39) t49 136.73 (9.13) 138.20 (5.92) t72 134.20 (12.16) 139.53 (5.71) t73 135.53 (12.41) 140.53 (5.08) rom = range of movement; us = ultrasound; sd = standard deviation. sajsm vol. 26 no. 4 2014 103 around issues of truthfulness and a patient’s autonomy rather than the efficacy of the intervention. deception may undermine the trust that is so important in a good patient-therapist relationship, and compromise the principles of informed consent. however, deception may not be obligatory, because the therapeutic ritual itself is thought to cause the placebo effect.[14] the power of the therapeutic context has repeatedly been demonstrated in comparisons between hidden and open administration of analgesics: analgesia that is administered openly has a far more powerful effect than the same medication given covertly.[3] what has not yet been well investigated is whether the therapeutic context alone can produce adequate analgesia without a specific therapy. however, medical professionals are well placed to use listening, empathy and patient-centred communication so as to encourage patients to expect positive outcomes. miller and colloca[14] argue that it is not necessary to use deception when explaining treatments that are known to be strongly placebo driven. they suggest that a therapist should explain to the patient that studies have found both the active and sham modalities to produce notable and equal improvements. the point is that it doesn’t matter which version of intervention the patient receives, as long as they receive one. to be acceptable, this explanation needs to be based on good evidence that sham and active treatments are equally helpful. strengths and limitations in this study, each participant acted as her own control. this was a notable advantage of the design. this, together with the double blinding, ensured that the centrally controlled, systemic placebo response would be induced equally in both the active us and sham us arms, while local treatment (active us effects) would occur in the active us arm only. the symptoms of doms are known to differ between subjects[6] and the subjective experience of pain cannot be compared accurately between different people. differences in symptoms should therefore be compared in the same person, as was done here. in this study, the timing of administration of us was based on the findings of the pilot study, not tailored to each participant. changes in symptoms were not monitored. however, participants in this study acted as their own controls. since it is unlikely that doms would occur asymmetrically in a single participant, any difference in timing should not have influenced the comparisons across time or groups. participants’ other activities during the study were not controlled or monitored, although participants were asked not to do any strenuous physical activity during the experiment. varying activity levels could have had an effect on the level of doms symptoms, potentially confounding results. again, marked differences in biceps activity is unlikely to have occurred asymmetrically within a single participant. whether the improvement in pain is due to the natural resolution of symptoms or the placebo effect cannot be ascertained without a non-treatment control group. however, the lack of measurable improvement during the 23-h period between treatment sessions, compared with the significant decrease in pain after each 1-h treatment session, suggests that little of the improvement recorded after treatment was due to spontaneous resolution. conclusion this study showed that active us (1 mhz, 0.4 w/cm2, pulsed 1:4) and sham us (1 mhz, 0 w/cm2, pulsed 1:4) therapy produce equivalent improvements in pain when used to treat doms of the biceps in the context of a therapeutic encounter. these results suggest that us does reduce pain, but does so via a placebo effect rather than by a local, tissue-specific effect. clinicians should be guided by this knowledge when choosing between interventions to reduce patients’ pain. further research is required to determine whether or not the therapeutic context is sufficient to elicit a placebo effect, even in the absence of a specific therapy. however, what is increasingly clear is that nearly every specific therapy also has some placebo value. clinicians can capitalise on this placebo value with communication strategies that improve the patient’s experience of the therapeutic encounter and encourage the patient to expect a positive outcome. because anxiety interferes with the opioid-mediated mechanism of placebo analgesia, we suggest that clinicians will also need to recognise and address patients’ anxiety if the placebo value is to be harnessed. capitalising on the placebo value of the therapeutic encounter will boost the analgesic efficacy of therapeutic interventions and achieve greater benefit for patients. acknowledgements. experiment funding was obtained through the university of cape town’s undergraduate physiotherapy programme. the authors thank s bacon, d gabriel, c le grange, w morris, k wood and c ziervogel for their assistance in conducting the study. references 1. baker kg, robertson vg, duck fa. a review of therapeutic ultrasound: biophysical effects. phys ther 2001;81(7):1351-1358. 2. robertson vj, baker kg. a review of therapeutic ultrasound: effectiveness studies. phys ther 2001;81(7):1339-1350. 3. benedetti f. placebo and endogenous mechanisms of analgesia. handb exp pharmacol 2007;177:393-413. [http://dx.doi.org/10.1007/978-3-540-33823-9_14] 4. crow r, gage h, hampson s, hart j, kimber a, thomas h. the role of expectancies in the placebo effect and their use in the delivery of health care: a systematic review. health technol assess 1999;3(3):1-96. 5. cheung k, hume pa, maxwell l. delayed onset muscle soreness: treatment strategies and performance factors. sports med 2003;33(2):145-164. 6. connolly daj. treatment and prevention of delayed onset muscle soreness. j strength cond res 2003;17(1):197-208. 7. cleather dj, guthrie sr. quantifying delayed-onset muscle soreness: a comparison of unidimensional and multidimensional instrumentation. j sports sci 2007;25(8):845850. [http://dx.doi.org/10.1080/02640410600908050] 8. rothstein jm, miller pj, roettger rf. goniometric reliability in a clinical setting. elbow and knee measurements. phys ther 1983;63(10):1611-1615. 9. craig ja, bradley j, walsh dm, baxter bd, allen jm. delayed onset muscle soreness: lack of effect of therapeutic ultrasound in humans. arch phys med rehabil 1999;80(3):318-323. [http://dx.doi.org/10.1016/s0003-9993(99)90144-2] 10. stay jc. pulsed ultrasound fails to diminish delayed-onset muscle soreness symptoms. j athl train 1998;33(4):341-346. 11. wittink hm, strassels sa, carr db. health outcomes and treatment effectiveness in pain medicine. in: wittink hm, carr db, eds. pain management: evidence, outcomes and quality of life. edinburgh: elsevier, 2008:1-20. 12. hashish i, hai hk, harvey w, feinmann c, harris m. reduction of postoperative pain and swelling by ultrasound treatment: a placebo effect. pain 1988;33(3):303-311. 13. gam an, johannsen f. ultrasound therapy in musculoskeletal disorders: a metaanalysis. pain 1995;63(1):85-91. 14. miller fg, colloca l. the legitimacy of placebo treatments in clinical practice: evidence and ethics. am j bioeth 2009;9(12):39-47. [http://dx.doi. org/10.1080/15265160903316263] 15. petrovic p, kalso e, petersson km, ingvar, m. placebo and opioid analgesia: imaging a shared neuronal network. science 2002;295(5560):1737-1740. [http://dx.doi.org/10.1126/ science.1067176] 16. price dd, finniss dg, benedetti f. a comprehensive review of the placebo effect: recent advances and current thought. annu rev psychol 2008;59:565-590. [http:// dx.doi.org/10.1146/annurev.psych.59.113006.095941] km_c227-20180511093412 original research sajsm vol. 24 no. 4 2012 129 case study the simultaneous destruction of skeletal muscle cells with the consequent release of cellular contents into the circulatory system is called rhabdomyolysis and can be triggered by mechanical injury, ischaemia, infections, or genetic alterations to drugs and toxins.1 the intrinsic characteristics of muscle tissue make it especially vulnerable to drug-related cell damage. although rare, the life-threatening illness of acute steroid myopathy causing rhabdomyolysis in patients on high-dose corticosteroids should be recognised by clinicians and sports medicine specialists. this article presents the case of a young golf player with rhabdomyolysis, as well as current theories on cellular mechanisms, and symptoms and treatment of acute corticosteroid-induced rhabdomyolysis. case report a 27-year-old professional golf player presented with neck and back pain suggestive of an inflammatory arthropathy. symptoms included polyarthralgia of the elbows, shoulders, knees and right foot as well as morning stiffness for longer than one hour. the morning stiffness and polyarthritis responded to anti-inflammatory drugs. on physical examination he had a normal schober test and chest expansion. while systemic and neurological examination was normal, the faber test was positive bilaterally with tenderness of the sacroiliac (si) joints and thoracic spinous processes. the initial differential diagnosis included possible spondylarthropathy, and mechanical neck and back pain. further tests revealed a normal full blood count. erythrocyte sedimentation rate was 2 mm/h and c-reactive protein levels were 2 mg/l. hla b27, rheumatoid factor and anti-cyclical citrillunated peptide antibody tests were negative. the isotope bone scan reported low-grade inflammatory changes in the superior part of the si joints and normal uptake in the spine and peripheral joints. the lumbar spine radiograph showed slight degeneration of the l5/s1 facet joints. the neck radiograph showed torticollis, while the thoracic spine radiograph showed kyphosis. having failed to respond to physiotherapy and anti-inflammatory drugs, he was admitted to hospital for a trial of intravenous therapeutic agents. a high dose of intravenous cortisone (125 mg methylprednisolone twice daily) was infused, backache of inflammator y origin typically responding to this form of management. the baseline creatine kinase (ck) level was 67 iu/l. the following day (day 2 of hospital admission) the patient had generalised myalgia and stiffness. ck levels were elevated at 1 568 iu/l and myoglobin at 448 mg/ml. phosphate, magnesium and electrolyte levels were normal, as was troponin t. thyroid function was also normal and the patient’s history and clinical course were not supportive of metabolic myopathy. the patient also denied any changes in his training programme, the use of drugs such as statins or colchisine, nutritional supplementation or exposure to toxins such as snake venom. therefore all other possible causes for the elevated ck and myoglobin levels were eliminated. on day 3 of hospital admission, the patient’s ck was markedly elevated at 4 609 iu/l and the myoglobin was 1 566 ng/ml. he was treated with intravenous fluid, sodium bicarbonate and mannitol to prevent renal failure and arrhythmias due to increased potassium levels. the cortisone treatment was also discontinued. on the fourth day of hospitalisation the ck level was 8 030 iu/l and the myoglobin 172 mg/ml. on day 5 the levels decreased to 3 301 iu/l and 129 mg/ml, respectively (the second day after cortisone treatment was stopped). the diagnosis of acute steroid-induced rhabdomyolysis was based on the combination of symptoms and biochemical markers with subsequent clearance of both after cessation of steroid therapy. discussion the association between high-dose corticosteroid administration and muscle weakness was first reported by cushing in 1932.2 acute corticosteroid-induced rhabdomyolysis in a golf player d c janse van rensburg, w theron, t c grant, p cele zondi, c c grant section sports medicine, university of pretoria d c janse van rensburg, md t c grant, bsc p cele zondi, mb chb c c grant, phd physician in private practice (collaborating with section sports medicine) w theron, fcp (sa) corresponding author: d c janse van rensburg (christa.jansevanrensburg@up.ac.za) acute corticosteroid-induced rhabdomyolysis is a rare, but potentially life-threatening, condition that deserves the attention of medical professionals and sport scientists. early diagnosis is vital in minimising the secondary damage caused by rhabdomyolysis. this case of rhabdomyolysis highlights the severity of symptoms and the importance of decisive treatment. clinicians should be familiar with the most common symptoms of acute corticosteroid-induced rhabdomyolysis to enable early diagnosis and efficient management of this condition. s afr j sm 2012;24(4):129-130. doi:10.7196/sajsm.339 130 sajsm vol. 24 no. 4 2012 corticosteroid-induced myopathy is a disease that mainly causes weakness of the proximal muscles of the upper and lower limbs and the neck flexors.3 it is caused by an excess of corticosteroids from endogenous or exogenous sources such as adrenal tumours or steroid treatment. there are two distinct types of corticosteroidinduced myopathy, namely chronic and acute,3 which may pose the risk of rhabdomyolysis development. the chronic type of myopathy is caused by prolonged exposure to corticosteroids, while the acute type is less common and occurs abruptly when the patient is receiving high doses of corticosteroids. previous cases of myopathy have been reported in patients receiving cortisone treatment for acute asthma,2 patients with phaeochromocytoma,4 and those in intensive care units.5 acute myopathy induced by high-dose corticosteroid treatment differs significantly from chronic myopathy. this suggests a different pathogenesis.2 willams et al.2 described the main differences between chronic and acute myopathy as listed in table 1. cellular mechanism of rhabdomyolysis the specific physiological mechanisms by which the different drugs act during rhabdomyolysis are uncertain.3,6 current research suggests that several factors play a role in the development of rhabdomyolysis, such as decreased protein synthesis and sarcolemmal excitability, increased protein degradation, modifications in carbohydrate metabolism, mitochondrial changes and electrolyte disturbances. steve lim (2010) suggests that the use of fluorinated steroids such as dexamethasone or triamcinolone more frequently causes steroid myopathy than non-fluorinated steroids such as prednisone or hydrocortisone.3 muscles that are less active are more likely to be affected by corticosteroid, meaning that a sedentary lifestyle may increase the risk of muscle weakness.3,5 interestingly, gender also seems to be a risk, as women are twice as likely as men to develop muscle weakness.4 martin hohenegger6 described the cellular mechanism by which rhabdomyolysis develops. it begins with a decrease in intracellular atp and a simultaneous increase in myoplasmic calcium (ca2+) concentrations.6 this leads to a deficiency in atp supplied by the mitochondrial chain, leading to reduced replenishment of ca2+ stores and extrusion of ca2+ to the extracellular space.6 calpain proteases are activated by the long-term elevated ca2+ levels that further degrade the proteins participating in ca2+ homeostasis. this intensifies the myoplasmic ca2+ overload.7 high cytosolic calcium has various detrimental effects. firstly, the mitochondria are overcome, leading to the disruption of oxidative phosphorylation, which decreases the available atp. secondly, apoptosis is triggered by the increased production of reactive oxygen species by the mitochondria, leading to the free radical disruption of cell and organelle membranes. thirdly, a series of proteases and phospholipases are activated, damaging the myofibrillar network.1 symptoms and treatment rhabdomyolysis is preceded by muscle weakness, muscle stiffness, symptoms of myalgia, swelling, tenderness and tea-coloured urine.1 there are, however, no clear laboratory parameters that estimate the risk a patient has of developing rhabdomyolysis,6 and a single symptom is not enough to make a definite diagnosis of rhabdomyolysis. clinicians should be alert to the presence of the following possible indicators:1 • a serum ck level >1 000 u/l is important in determining whether the patient is suffering from rhabdomyolysis.1 typically, the serum concentration of ck rises in the first 12 hours after injury, peaks at 3 days, and normalises at approximately 5 days.1 • damaged muscles rapidly release myoglobin, leading to elevated serum and urinary myoglobin concentrations. levels peak at 8 12 hours, but typically normalise in serum within 24 hours.1 this was also found in our patient. • a urine dipstick will indicate 'blood' in the urine, indicating presence in this case of myoglobin (not haemoglobin). as such, a combination of myoglobinuria and elevated plasma ck levels confirms the diagnosis of rhabdomyolysis.1 • e l e c t r o l y t e a b n o r m a l i t i e s s u c h a s h y p e r k a l a e m i a , hyperphosphataemia and hypocalcaemia occur, but are not specific enough for diagnostic certainty.1 administration of the rhabdomyolysing agents/medication should be stopped immediately to prevent further skeletal muscle damage.6 control of fluid equilibrium is vital to stabilise the circulation and serum potassium and to prevent acidosis.1,6 after the corticosteroid dose is reduced or discontinued, the steroid-induced muscle weakness decreases, although it can take weeks or months for full recovery.3 conclusion acute corticosteroid-induced rhabdomyolysis is rare but potentially life-threatening. early diagnosis is vital in minimising the secondary damage. references 1. parekh r. emergency medicine practice. rhabdomyolysis: advances in diagnosis and treatment. eb medicine.net, 2012. http://www.ebmedicine.net/store. php?paction=showproduct&pid=258 (accessed 1 september 2012). 2. williams tj, o’hehir re, czarny d, horne m, bowes g. acute myopathy in severe asthma treated with intravenously administered corticosteroids. am rev respir dis 1988;137:460-463. 3. lim ss. medscape reference: drugs, diseases and procedures. corticosteroidinduced myopathy, 2010. http://emedicine.medscape.com/article/313842-overview (accessed 1 september 2012). 4. takahashi n, shimada t, tanabe k, et al. steroid-induced crisis and rhabdomyolysis in a patient with pheochromocytoma: a case report and review. int j cardiol 2011;146:e41-e45. [http://dx.doi.org/10.1016/j.ijcard.2008.12.183] 5. hanson p, dive a, brucher j, bisteau m, dangoisse m, deltome t. acute corticosteroid myopathy in intensive care patients. muscle nerve 1997;20:1371-1380. 6. hohenegger m. drug induced rhabdomyolysis. curr opin pharmacol 2012;12:1-5. [http://dx.doi.org/10.1016/j.coph.2012.04.002] table 1. main differences between chronic and acute myopathy chronic myopathy acute myopathy muscle weakness proximal muscles proximal and distal muscles ck levels normal/slightly elevated significantly higher, possible rhabdomyolysis muscle biopsy type iib fibre atrophy focal and diffuse necrosis original research 50 sajsm vol. 27 no. 2 2015 background. concussion is a significant health issue in rugby union. however, little is known about players’ levels of concussion knowledge or return-to-play (rtp) attitudes. objectives. to determine the concussion knowledge and concussion-related rtp attitudes of subelite rugby union players in south africa. methods. subelite rugby union players (n=127; mean age 24.1 years) completed a measure of concussion knowledge and a concussionrelated rtp attitude scale. frequencies were calculated with regard to concussion knowledge and rtp attitudes for the total sample, as well as separately for previously concussed and non-concussed participants. pearson’s χ2 tests and t-tests for independent groups were employed to determine significant differences in concussion knowledge and rtp attitudes between previously concussed and nonconcussed participants. results. participants displayed varying, yet generally less than optimal levels of concussion knowledge. knowledge of concussion-related rtp protocols (20 23%) and the efficacy of safety equipment (20 25%) was particularly poor. the subelite rugby players included in the sample did not hold notably conservative rtp attitudes, with the majority expressing a willingness to participate in practice (74%) and competition (47 56%) without having fully recovered from a concussion. no significant differences were apparent with regard to the rtp attitudes and concussion knowledge of the previously concussed and non-concussed players. conclusion. the general level of concussion knowledge among subelite rugby union players appears less than optimal. moreover, the majority of these players expressed an intention to rtp before they had fully recovered from concussion. s afr j sports med 2015;27(2):50-54. doi:10.7196/sajsm.536 concussion knowledge and return-to-play attitudes among subelite rugby union players sp walker, msocsc (couns psych), phd unit for professional training and services in the behavioural sciences (unibs), faculty of the humanities, university of the free state, bloemfontein, south africa corresponding author: sp walker (walkersp@ufs.ac.za) concussion has been identified as a high priority health issue in rugby union.[1-4] an incidence of 7.97 concussions per 1 000 player game hours has been reported for nonprofessional australian rugby players.[1] concussions accounted for 9.7% of the injuries reported for elite southern hemisphere rugby union players across one season, while constituting 4.8% of injuries reported across the same season of english premiership rugby.[5] in south africa (sa), the seasonal incidence of concussion has been estimated to range from 4% to 14% at school level and between 3% and 23% at senior level.[2] however, a number of researchers contend that it is extremely difficult to accurately determine the incidence of sport-related concussion and that the current research literature might significantly underestimate the extent of the problem.[6,7] effective concussion prevention and management has been highlighted as a priority in contact sports in general, and particularly in rugby union. a series of consensus statements have called for the implementation of uniform measures aimed not only at the effective identification and management of concussion, but also at a reduction in the incidence of concussion in contact sports.[8,9] these consensus statements recommend focusing on (i) the standardised identification and management of concussion, (ii) the implementation of regulations and rule changes in various sporting codes intended to reduce the risk of concussion, and (iii) the implementation of education initiatives aimed at increasing awareness of sport-related concussion. these recommendations have been officially adopted and implemented by numerous sporting bodies across the world, including the international rugby board (irb) and the south african rugby union (saru).[3,10] the administrative and medical guidelines recommended in the consensus statements on sport-related concussion appear to have been partially effectively implemented in rugby union. uniform processes for screening for and diagnosing concussion, as well as specific return-to-play (rtp) guidelines have been implemented by saru at both the professional and amateur levels.[3] however, while a number of broad-based concussion education initiatives have been introduced worldwide, these appear to have had a less than optimal impact on the concussion-related knowledge and behaviour of rugby union players in a number of countries. one study found that 78% of concussed australian amateur rugby union players did not receive any rtp advice.[11] moreover, those players who did receive rtp advice generally failed to follow those guidelines. similarly, a study conducted in new zealand indicated that a significant proportion of schoolboy rugby players had limited concussion knowledge and failed to comply with recommended concussion-related rtp guidelines.[12] the parents of schoolboy rugby union players generally seemed more knowledgeable than their children with regard to the identification of concussion and the potential dangers thereof.[13] however, these parents still demonstrated less than optimal knowledge regarding recommended concussion-related rtp guidelines. similarly, a recent investigation into the concussion knowledge of coaches in australian rules football and rugby league concluded that the prescribed guidelines on concussion prevention and management did not sajsm vol. 27 no. 2 2015 51 appear to be filtering down to the coaches and paramedical staff involved in these sports in australia.[14] policy and rule changes seem to have contributed to a reduction in the incidence of concussion.[1,4] however, the limited number of studies published in the field suggest that educational inter ventions aimed at increasing concussion knowledge and promoting player compliance with rtp guidelines have been less successful. [11-14] this is of particular concern when the dangers associated with premature postconcussion rtp are considered. premature rtp following a concussion may result in a number of complications that include prolonging cognitive and self-regulation difficulties frequently associated with concussion, increasing the risk of subsequent concussions, post-concussion syndrome, second impact syndrome or even chronic traumatic encephalopathy.[4,15,16] there seems to be a dearth of information regarding the level of concussion knowledge and rtp attitudes among elite and subelite rugby union players both nationally and internationally. consequently, the current study aimed to determine the level of concussion knowledge among subelite rugby union players in sa. the study also aimed to explore concussion-related rtp attitudes in this population. methods participants ethical clearance to conduct the study was obtained from the relevant institutional body. two provincial rugby unions granted permission for data to be collected among clubs registered under their auspices. seven of a potential 25 clubs agreed to participate in the study and informed consent was obtained from 139 subelite rugby union players. participants completed the measures listed below before or after practices, depending upon the preferences of their coaches. twelve questionnaires were excluded due to incomplete data. the mean age of the final sample (n=127) was 24.1 years (standard deviation (sd) 4.9). fifty-one (40%) participants reported club rugby as their highest level of competition, while 16% had competed provincially at under-19 level and 17% at under-21 level. twenty players (16%) reported selection for development teams as their highest level of competition. measures concussion knowledge was measured by means of a 13-item multiple-choice questionnaire based on previous work done among coaches and healthcare professionals in primar y school rugby.[17] items on the questionnaire sampled knowledge regarding the identification of concussion, concussion risks, the management of concussion and rtp guidelines.[9] each item was presented as a question or statement with one correct response and a number of distractors. the questionnaire was scored by awarding one mark for endorsement of the correct response to each question and zero for endorsement of one of the distractors. the scores across all 13  items were added to yield a total concussion knowledge score. concussion-related rtp attitudes were measured via a five-item questionnaire compiled by the researcher. respondents were required to indicate the extent to which they would be inclined to participate in a practice, play a friendly game, play in a league final, participate in provincial trials and participate in national trials despite not having fully recovered from a concussion. responses were recorded along a five-point likert-type scale anchored by (1) should/ would definitely play and (5) should/would definitely not play. both measures were translated into afrikaans via the back-translation method.[18] the questionnaires were administered in either english or afrikaans depending upon participant preference. biographical data pertaining to age and highest level of competition were collected. participants were required to indicate whether they had ever suffered a concussion by endorsing one of three response options (yes, no or unsure). those participants stating that they had previously been concussed were also required to indicate the number of concussions they had suffered across their playing careers. analysis descriptive statistics were calculated with regard to the number of rugby-related concussions reported by the participants. the 13 concussion knowledge items were scored and frequencies were calculated for the sample as a whole. furthermore, in order to investigate whether players reporting a history of concussion differed from those reporting no history of concussion with regard to their concussion knowledge, frequencies were also calculated for the previously concussed and previously non-concussed participants separately. pearson’s χ2 tests were conducted to determine the statistical significance of any differences in the scores obtained by previously concussed and non-concussed participants on the concussion knowledge items.[19] in addition, the number of individuals indicating a definite intention not to return to play or practice before fully recovering from concussion was calculated for each of the five concussionrelated rtp scenarios. these frequencies were calculated for the total sample, as well as for the previously concussed and nonconcussed groups separately. pearson’s χ2 tests were employed to determine whether any statistically significant differences were apparent in the concussion-related rtp attitudes of the previously concussed and non-concussed players. independent groups’ t-tests were also employed to determine whether the total concussion knowledge and mean rtp attitudes of the two groups differed significantly. all analyses were performed using the statistical software package for the social sciences (spss), version 21 (ibm corporation, usa).[20] results the frequency distribution in the sample with respect to the number of rugby-related concussions is shown in table 1. it is evident from table 1 that the majority (59%) of the participants reported having suffered at least one concussion during their rugby playing careers. furthermore, 31% indicated that they had been concussed on two or more occasions. ten players (8%) reported suffering four or more concussions. the level of concussion knowledge possessed by the subelite rugby union players participating in the study is reported in table 2. these data table 1. frequency distribution for rugby-related concussions (n=127) number of concussions n (%) 0 52 (41) 1 36 (28) 2 17 (13) 3 12 (10) 4 6 (5) 5 4 (3) total 127 (100) 52 sajsm vol. 27 no. 2 2015 are displayed for the sample as a whole, as well as for the previously concussed and non-concussed participants. the data displayed in table 2 indicate that correct response rates of 80% and above were recorded for four of the 13 concussion knowledge items. the vast majority of the respondents (95%) were aware that a concussion was a brain injury, 87% were aware that a previous concussion increased the risk of a player suffering a concussion in the future and 84% correctly indicated that concussion-related rtp decisions should be made by a medical doctor. furthermore, 82% of the participants were aware that concussion can be present in the absence of positive neuroimaging findings. the majority (78%) of the participants incorrectly believed that a scrum cap offers effective protection against concussion. ninety-six (76%) of the players participating in the study believed that while a scrum cap would not completely prevent a concussion, it did serve a protective function. only 21% of the sample correctly stated that a professional rugby player could only rtp once he had been cleared by a medical doctor. most (58%) participants were of the opinion that a professional player who had suffered a concussion could play in the next match without being cleared by a medical doctor, provided the match was played at least 2 days after the incident in which he suffered the concussion. an additional 16% believed that this player could rtp during the same game in which the concussion had been suffered as long as he was cleared by the team’s medical staff. slightly less than half (46%) of the rugby players who participated in the study displayed inadequate knowledge relating to the range of activities that individuals recovering from concussion should avoid. furthermore, only 61% of the sample identified concussion-related education as the most effective means of reducing the incidence of sport-related concussion. developing strong neck muscles was viewed as the most effective means of reducing the risk of concussion by 13% of the sample, while 13% believed that proper stretching before and after exercise would be most effective, and 11% endorsed concussion education workshops for injured players as the most effective means of reducing the incidence of concussion. an independent-samples t-test indicated no significant difference table 2. concussion knowledge for the total sample and by reported concussion history concussion knowledge item percentage of correct responses (%) χ2 p-value total (n=127) pc (n=75) n-c (n=52) a concussion is a brain injury 95 93 98 1.535 0.215 previous concussions place a player at increased risk of future concussion 87 88 85 0.303 0.582 aware that rtp decisions should be made by a doctor 84 85 83 0.161 0.688 a normal brain scan does not rule out a concussion 82 84 79 0.550 0.458 concussions are most frequently incurred during tackles 79 85 69 4.757 0.029* loss of consciousness is not a prerequisite for a concussion 78 81 73 1.218 0.270 adequate awareness of general rtp guidelines for amateur players 77 81 71 1.806 0.179 a player who suffers a severe blow to the head should stop playing immediately 72 69 77 0.886 0.347 a player who suffers a severe blow to the head should not be allowed to play again that day 69 72 65 0.632 0.427 education is the most effective manner to reduce the incidence of sport-related concussion 61 60 64 0.155 0.694 adequate awareness of activities that players recovering from concussion should avoid 54 59 48 1.388 0.239 a scrum cap does not provide protection against concussion 22 20 25 0.447 0.504 adequate awareness of general rtp guidelines for professional players 21 20 23 0.174 0.677 pc = previously concussed; n-c = non-concussed. *p≤0.05 table 3. concussion-related rtp attitudes for the total sample and by concussion history. rtp attitude percentage endorsing attitude (%) χ2 p-value total (n=127) pc (n=75) n-c (n=52) would definitely not practice before fully recovering from a concussion 26 25 27 0.517 0.972 would definitely not play a practice game before fully recovering from a concussion 53 52 54 3.226 0.521 would definitely not play in a league final before fully recovering from a concussion 47 40 56 4.488 0.344 would definitely not participate in provincial trials before fully recovering from a concussion 44 39 52 7.335 0.119 would definitely not participate in national trials before fully recovering from a concussion 44 37 54 6.083 0.193 sajsm vol. 27 no. 2 2015 53 in the total concussion knowledge scores for the previously concussed participants (mean (sd), 9.6 (1.8)) and the non-concussed players (9.1 (2.1); t(125)=1.407, p=0.162). generally the players who reported previously having suffered a concussion provided a higher proportion of correct answers on 8 of the 13 concussion knowledge items. furthermore, a significantly larger proportion (χ2=4.757, p=0.029) of previously concussed players correctly identified tackles as the phase of play in which concussions were most frequently suffered. it is apparent from table 3 that the rugby players participating in the study generally did not hold particularly conservative or cautious attitudes with respect to returning to practice and competition after a concussion. only 26% indicated that they would definitely not return to practice before having fully recovered from a concussion. slightly fewer than half of the participants indicated that they would definitely not play in a league final (47%), participate in provincial trials (44%) or play in national trials (44%) before having fully recovered from a concussion. however, 53% indicated that they would definitely not play in a practice match before fully recovering. the data displayed in table 3 suggest that the players with no reported history of concussion tend to be slightly more cautious in their concussion-related rtp attitudes when compared to players with a history of concussion. however, no statistically significant differences were apparent between the two groups with regard to the individual concussion-related rtp scenarios (practice, friendly, league final and trials). moreover, an independent-samples t-test revealed no significant difference in the mean concussion-related rtp attitudes for the previously concussed participants (15.1 (4.2)) and the non-concussed players (16.1 (4.4); t(125)=–1.206, p=0.230). discussion the objective of this study was to determine the concussion knowledge and concussion-related rtp attitudes of subelite rugby union players. while not a primary objective of the research, data were also gathered with regard to self-reported lifetime incidence of rugby-related concussion. the incidence of concussion reported by the rugby union players in this study indicates that more than half the sample had suffered at least one concussion and almost a third had been concussed on two or more occasions. it is conceded that the primary objective of this study was not to determine the incidence of concussion among subelite rugby players. consequently, the reported incidence of concussion should be viewed circumspectly, not least as a result of the methodological limitations with regard to determining the incidence of concussion in this study. the participants displayed a relatively high level of knowledge with regard to what constitutes a concussion, the risk that a history of concussion holds with regard to future concussion, and the authority that should rest with medical doctors in clearing players to rtp following concussion. participants in the current study demonstrated superior knowledge in this respect compared with that reported for australian rules football and rugby league coaches and trainers in australia.[14] the previously concussed players were also reasonably knowledgeable about the phase of play in which a concussion was most likely to be suffered. moreover, these players were significantly more inclined to endorse the correct answer in this regard compared to those participants who had not previously been concussed. similar, though not significant, differences were apparent between previously concussed players and players with no history of concussion with regard to knowledge of a loss of consciousness not being a prerequisite for the diagnosis of a concussion, as well as what constitutes adequate rtp guidelines for amateur players. these findings raise the possibility that some aspects of players’ concussion knowledge are perhaps more a function of personal experience of having been concussed than of effective information dissemination and education. in excess of a third of the participants did not view educational initiatives as the most effective means of reducing the incidence of concussion in rugby union. similar to findings in other countries, not only are educational indicatives in saru seemingly not having the desired impact, but a substantial proportion of subelite players do not view information dissemination initiatives as an effective means of reducing concussion rates.[12-14,17,21] slightly more than half of the participants demonstrated adequate knowledge regarding the range of activities that players recovering from concussion should avoid, and the vast majority (79%) were of the opinion that professional players could rtp much faster than amateurs. although the reasons for the latter view are not apparent, it is troubling that there appears to be a perception that players competing at higher levels are somehow less affected by concussion. less than adequate knowledge regarding the activities recovering players should refrain from is perhaps further evidence of the work that still has to be done with regard to effectively disseminating rtp information at all levels of the game. in addition, the widely held misperception that a scrum cap provides protection against concussion also appears to suggest that accurate information is not reaching players. however, it is possible that this particular misperception might be more due to commercial product promotion than ineffective dissemination of information. the concussion knowledge of the participants in this study seemingly failed to translate into appropriately cautious rtp attitudes. it is of particular concern that almost three-quarters of the participants indicated that they would, to some extent, be inclined to participate in a practice despite not having fully recovered from a concussion. this finding, along with less than half of the participants indicating that they would not participate in important matches or trials before having fully recovered from concussion, might at least partially result from the relatively low levels of knowledge regarding rtp guidelines reported earlier. taken together, the findings with regard to rtp attitudes are consistent with other studies on concussion-related rtp.[11-14,21,22] furthermore, the discrepancy between the participants’ knowledge and their rtp attitudes suggests that knowledge alone is not sufficient to bring about attitudinal and behavioural change in this regard. it would be advisable for future initiatives to specifically target attitudes and motivation in addition to the existing information dissemination strategies.[23] study limitations the current sample was drawn from only two metropolitan areas. consequently, the findings cannot be reliably generalised beyond this specific geographical context. the methodology employed in the study is not appropriate for validly determining concussion incidence. this is primarily due to the fact that participant recall was relied upon rather than objective records of diagnosed concussions. in addition, participants were not provided with a definition of concussion in order to help them determine whether or not they may have been previously 54 sajsm vol. 27 no. 2 2015 concussed. the findings relating to the incidence of concussion within the sample should thus be treated circumspectly. no indication of concussion knowledge prior to the implementation of various saru sanctioned educational initiatives could be found. as a result, the extent to which these initiatives have succeeded or failed in improving player knowledge could not be determined. similarly, the items used to determine concussion knowledge were largely based on the general recommendations of the consensus statements on concussion in sport and do not necessarily provide a valid indication of the extent to which players have internalised the particular information communicated via the existing education programmes. future research should ensure closer correlation between the information provided by these initiatives and the content of measures of player concussion knowledge. conclusion the rugby union players participating in the current study displayed satisfactory knowledge of what constitutes a concussion, the risks associated with repeated concussion and certain aspects of concussion identification or diagnosis. they exhibited less adequate knowledge on the field-side management of players suspected of having a concussion and a low level of knowledge with respect to concussion-related rtp guidelines. in addition, concussion knowledge did not appear to be related to rtp attitudes. while current concussion education initiatives appear to have been partially successful, additional methods of facilitating attitudinal and behavioural changes need to be considered. references 1. hollis sj, stevenson mr, mcintosh as, et al. incidence, risk, and protective factors of mild traumatic brain injury in a cohort of australian non-professional male rugby players. am j sports med 2009;37(12):2328-2332. [http://dx.doi. org/10.1177/0363546509341032] 2. shuttleworth-edwards ab, noakes td, radloff se, et al. the comparative incidence of reported concussions presenting for follow-up management in south african rugby union. clin j sports med 2008;18(5):403-409. [http://dx.doi.org/10.1097/ jsm.0b013e3181895910] 3. viljoen w, patricios j. boksmart – implementing a national rugby safety programme. br j sports med 2012;46(10):692-693. [http://dx.doi.org/10.1136/ bjsports-2012-091278] 4. patricios js, kohler rmn, collins rm. sports-related concussion relevant to the south african rugby environment: a review. s afr j sports med 2010;22(4):88-94. 5. fuller cw, raftery m, readhead c, et al. impact of the international rugby board’s experimental law variations on the incidence and nature of match injuries in southern hemisphere professional rugby union. s afr med j 2009;99(4);232-237. 6. haseler cm, carmont mr, england m. the epidemiology of injuries in english youth community rugby union. br j sports med 2010;44(15):1093-1099. [http://dx.doi. org/10.1136/bjsm.2010.074021] 7. bailes je. sport-related concussion: what do we know in 2009 – a neurosurgeon’s perspective. j int neuropsych soc 2009;15(4);509-511. [http://dx.doi.org/10.1017/ s1355617709090936] 8. harmon kg, drezner ja, gammons m, et al. american medical society for sports medicine position statement: concussion in sport. br j sports med 2013;47(1):15-26. [http://dx.doi.org/10.113/bjsports-2012-091941] 9. mccrory p, meeuwisse wh, aubry m, et al. consensus statement on concussion in sport: the 4th international conference on concussion in sport held in zurich, november 2012. br j sports med 2013;47(5):250-258. [http://dx.doi.org/10.1136/bjsports-2013-092313] 10. international rugby board. international rugby board strategic plan 2010 2020. dublin: international rugby board, 2010. 11. hollis sj, stevenson mr, mcintosh as, et al. compliance with return-to-play regulations following concussion in australian schoolboy and community rugby union players. br j sports med 2012;46(10):735-740. [http://dx.doi.org/10.1136/ bjsm.2011.085332] 12. sye g, sullivan sj, mccrory p. high school rugby players’ understanding of concussion and return to play guidelines. br j sports med 2006;40(12):1003-1005. [http://dx.doi. org/10.1136/bjsm.2005.020511] 13. sullivan sj, burne l, choie s, et al. understanding of sport concussion by parents of young rugby players: a pilot study. clin j sports med 2009;19(3):228-230. [http:// dx.doi.org/10.1097/jsm.0b013e318a41e43] 14. white pe, newton jd, makdissi m, et al. knowledge about sports-related concussion: is the message getting through to coaches and trainers? br j sports med 2014;48(2):119-124. [http://dx.doi.org/10.1136/bjsports-2013-092785] 15. johnson ve, stewart je, begbie fd, et al. inflammation and white matter degeneration persists for years after a single traumatic brain injury. brain 2013;136(1):28-42. [http:// dx.doi.org/10.1093/brain/aws322] 16. mckee ac, stein ta, nowinski cj, et al. the spectrum of disease in chronic traumatic encephalopathy. brain 2013;136(1):43-64. [http://dx.doi.org/10.1093/brain/aws307] 17. jansen van rensburg m. concussion knowledge and practice among role players in primary school rugby in the north west province. unpublished master’s dissertation. bloemfontein: university of the free state, 2013. 18. brislin rw. back-translation for cross-cultural research. j cross-cultural res 1970;1(3):185-216. 19. howell dc. statistical methods for psychology. 8th ed. belmont: thomson wadsworth, 2013. 20. ibm corporation. ibm statistics for windows, version 21.0. new york: ibm, 2012. 21. kroshus e, daneshvar dh, baugh cm, et al. ncaa concussion education in ice hockey: an ineffective mandate. br j sports med 2014;48(2):135-140. [http://dx.doi. org/10.1136/bjsports-2013-092498] 22. provvidenza c, engebretsen l, tator c, et al. from consensus to action: knowledge transfer, education and influencing policy on sports concussion. br j sports med 2013;47(5):332-338. [http://dx.doi.org/10.1136/bjsports-2012-092099] 23. barkoukis v, lazarus l, tsorbatzoudis h, rodafinos a. motivational and sportspersonship profiles of elite athletes in relation to doping behaviour. ps ychol sp or t e xe rc 2 0 1 1 ; 1 2 ( 3 ) : 2 0 5 2 1 2 . [ http : / / d x . d oi. org / 1 0 . 1 0 1 6 / j. psychsport.2010.10.003] sajsm 498.indd original research sajsm vol. 25 no. 4 2013 105 background. burnout among adolescent athletes is a cause for concern. however, little is known about the intrapersonal factors that may be related to burnout in this population. objectives. to explore the relationship between burnout and mindfulness among competitive adolescent tennis players. methods. competitive adolescent tennis players (n=104; mean age 16 years) completed measures of mindfulness and athlete burnout. correlations were calculated with regard to mindfulness and burnout. a one-way multivariate analysis of variance (manova) was conducted to determine whether athletes assigned to three levels of mindfulness (high, moderate and low) differed significantly with regard to burnout. results. mindfulness exhibited significant negative correlations with global burnout, emotional/physical exhaustion, reduced sense of accomplishment and sport devaluation. the results of the manova indicated that individuals in the three mindfulness groups (high, moderate and low) reported significantly different levels of burnout. post hoc analyses revealed that participants in the high mindfulness group reported a significantly lower sense of reduced accomplishment and global burnout than participants in the low mindfulness group. in addition, participants in the low mindfulness group reported significantly higher levels of global burnout than individuals in the high and moderate mindfulness groups. conclusion. mindfulness appears to be negatively related to athlete burnout among competitive adolescent tennis players. furthermore, athletes reporting different levels of mindfulness exhibit differing levels of burnout. the potential protective effect of mindfulness with regard to burnout among adolescent athletes warrants further investigation. s afr j sm 2013;25(4):105-108. doi:10.7196/sajsm.498 mindfulness and burnout among competitive adolescent tennis players s p walker, msocsc (couns psych), phd unit for professional training and service in the behavioural sciences (unibs), faculty of the humanities, university of the free state, bloemfontein, south africa corresponding author: s p walker (walkersp@ufs.ac.za) the escalating demands upon athletes compet ing at all levels of sport are increasingly linked with burnout and fatigue syndromes.[1-3] athlete burnout may be viewed as the long-term consequence of an imbalance between an athlete’s coping resources and the physical, social and psychological stress that they are exposed to on an ongoing basis through training and competition. in general, burnout is characterised by: (i) physical and emotional exhaustion; (ii) a reduced sense of accomplishment, most commonly manifested in reduced physical performance or the subjective perception that the athlete is no longer able to reach their specific performance goals; and (iii) the tendency to disinvest from, or to devalue participation in the chosen sport.[4] burnout has been linked to a number of negative outcomes among athletes, including reduced motivation, dysfunctional coping behaviour, depression, suboptimal response to training and withdrawal from competitive sport.[1,5-6] however, despite the realisation that athlete burnout is a significant problem, very little research has directly addressed burnout among adolescent athletes.[6] this is of particular concern given the association between athlete burnout and withdrawal from competitive sport among adolescents.[1,2] there is thus a need to develop a better understanding not only of the factors that contribute to burnout among adolescent athletes, but also of intrapersonal factors that may play a protective role in this regard. mindfulness may potentially serve a protective function with regard to athlete burnout. mindfulness has been described as the non-judgemental awareness of internal and external experiences as they occur in the present moment.[7] mindfulness has its basis in eastern meditation practice and has been positively associated with psychological well-being.[7] recently, mindfulness-based techniques and approaches have been introduced into western psychology through various stress-management programmes and cognitive-behavioural therapy modalities. these approaches have been shown to have a number of benefits including lower levels of anxiety and depression, as well as increased stress tolerance and improved psychological wellbeing.[8] mindfulness has also been successfully applied to the treatment of various psychological and psychosocial disorders.[9,10] in addition, mindfulness has been demonstrated to be effective in the promotion of health behaviours such as the initiation and maintenance of physical exercise regimens.[11] to date, however, most studies on mindfulness have focussed on the effect of mindfulness-based interventions on the well-being of individuals, rather than exploring the possible protective effect that existing levels of mindfulness may have when individuals are confronted with stressful life events. the vast majority of research on mindfulness in sport psychology has focused on the role of mindfulness-based interventions on sporting performance.[12,13] to date, only one study seems to have focused on 106 sajsm vol. 25 no. 4 2013 the efficacy of mindfulness as a means of treating athlete burnout. this case study reports a significant reduction in burnout symptoms, as well as an increase in subjective well-being and athletic performance in an olympic shotist.[14] however, the possible protective role of mindfulness with regard to athlete burnout does not appear to have been investigated, nor the relationship between mindfulness and burnout, among adolescent athletes. consequently, the objective of the current study was: (i) to determine whether a relationship exists between mindfulness and burnout among competitive adolescent tennis players; and (ii) if so, to determine whether adolescent tennis players with differing levels of mindfulness report different levels of burnout. methods participants ethical clearance to conduct the study was obtained from the relevant institutional body. the organisers of two national tennis tournaments gave permission for data to be collected. only tennis players aged 14 19 years were invited to participate in the study. informed consent was obtained from all participants, as well as from their guardians, prior to administration of the questionnaires. participants completed the measures listed below between matches or at the end of the day. one hundred and thirteen adolescents participated in the study. nine participants were excluded due to incomplete questionnaires. the mean age of the final sample (n=104) was 16 years (standard deviation (sd) ±1). the sample was evenly split with regard to gender, and participants reported having received a mean 6.3 years (sd ±2.7) of professional tennis coaching. the majority of participants (37%) reported provincial tournaments as their highest level of competition, while 28% competed at national level, 12% at regional level and 23% represented their schools. measures the athlete burnout questionnaire (abq) was used to measure burnout.[4] the abq is a 15-item self-report questionnaire that yields scores on three subscales: reduced sense of sport accomplishment; sport devaluation; and emotional/physical exhaustion. a total burnout score is also derived. responses to each item are indicated along a fivepoint likert-type scale anchored by ‘almost never’ and ‘almost always’. higher scores are indicative of higher levels of burnout. the abq has been demonstrated to have acceptable construct validity and internal consistency.[4] internal consistency was also found to be acceptable in the current sample (α=0.710 0.917). the freiburg mindfulness inventory (fmi) was used as a measure of mindfulness.[15] the fmi is a 14-item self-report questionnaire, with responses indicated along a four-point likert-type scale anchored by ‘rarely’ and ‘almost always’. a unitary mindfulness score is derived. higher scores indicate higher levels of mindfulness. a statisticallyderived eight-item version of the fmi has also been proposed. the shorter version of the questionnaire has been shown to be a reliable and valid measure of mindfulness.[15] in the interests of reducing respondent fatigue, the shorter fmi was employed in this study. the eight-item version fmi exhibited an acceptable level of internal reliability in the current sample (α=0.703). the abq and fmi were translated into afrikaans using backtranslation.[16] participants thus had the option of completing the questionnaires in either english or afrikaans. analysis pearson’s correlation coefficients were calculated with regard to mindful ness (fmi total score) and burnout (three abq subscales and total score). in addition, participants were divided into three levels of mindfulness (high, moderate and low) based on the distribution of the fmi scores in the sample. a one-way multivariate analysis of variance (manova) was then conducted to determine whether individuals in the three levels of mindfulness differed significantly with regard to their abq subscale and total mean scores. post hoc analyses (scheffé test) were conducted to determine the nature and direction of the significant differences yielded by the manova. results the correlations between the fmi and abq scores for the sample are provided in table 1. the mean scores, sds and internal consistencies for each of the scales are also reported. it is apparent that all the measures utilised in the study exhibited acceptable levels of internal consistency; they may thus be included in further analyses.[17] the correlation coefficients reported above suggest that mindfulness is negatively significantly correlated with all three abq subscales (reduced sense of accomplishment (-ra): p≤0.01; devaluation (-d): p≤0.01; and emotional/physical exhaustion (-e): p≤0.05), as well as with total burnout (p≤0.01). it would thus appear that higher levels of mindfulness are significantly associated with lower levels of athlete burnout in the current sample. given that a significant inverse relationship exists between mindfulness and burnout, it was decided to investigate whether individuals table 1. pearson correlation coefficients, means, sds, ranges and internal consistencies for the fmi and abq abq-ra abq-d abq-e total fmi mean (±sd) range α fmi -0.406* -0.300* -0.233† -0.354* 23.25 (±3.87) 14 32 0.703 total 0.756* 0.944* 0.878* 35.95 (±12.41) 15 68 0.917 abq-e 0.443* 0.774* 11.37 (±5.07) 5 25 0.888 abq-d 0.633* 11.74 (±5.42) 5 25 0.883 abq-ra 12.85 (±3.76) 5 20 0.710 *p≤0.01; †p≤0.05. fmi = freiburg mindfulness inventory (8-item total score); abq = athlete burnout questionnaire; abq-ra = abq reduced sense of accomplishment; abq-d = abq devaluation; abq-e = abq emotional/physical exhaustion; total = abq total score; sd = standard deviation. sajsm vol. 25 no. 4 2013 107 reporting different levels of mindfulness differed significantly with regard to the levels of burnout that they experienced. consequently, three levels (high, moderate and low) of the independent variable (mindfulness) were created by dividing the sample into thirds based on the distribution of their fmi scores (low: fmi≤21; n=36; moderate: fmi 22 25; n=41; high: fmi≥26; n=27). it should be noted, however, that mean abq scores reported in table 1 are not particularly high. consequently, the individuals in this study do not appear to be suffering from significant burnout. to control for the possible effect of gender and level of competition on mindfulness group membership, pearson’s χ2 tests were conducted. the results indicated a proportional distribution across the three levels of the independent variable (levels of mindfulness) when gender (χ2=1.395; df=2; p=0.498) and level of competition (χ2=12.527; df=6; p=0.051) were taken into account. it can therefore be assumed that individuals of both genders and all four levels of competition were proportionally and equally distributed across the three mindfulness groups. consequently, any differences in levels of burnout between these three groups could not be attributed to the effect of gender or level of competition. a one-way between-groups analysis of variance (anova) was conducted to investigate differences between the three levels (high, moderate and low) of the independent variable (mindfulness) with regard to athlete burnout. four dependent variables were included in the analysis: reduced sense of accomplishment (ra), devaluation (d), emotional/physical exhaustion (e) and total burnout (total). preliminary assumption testing was conducted to check for normality, linearity, univariate and multivariate outliers, homogeneity of variancecovariance matrices and multicollinearity. violations of the assumptions of homogeneity of variance-covariance were detected. consequently, a bonferroni adjusted α-level of 0.013 was used to determine statistical significance in the ensuing analyses. a statistically significant difference was apparent between the levels of mindfulness on the combined dependent variables (f (6; 198)=3.7441; p =0.001; wilks’ λ =0.807; partial η2=0.102). follow-up univariate anovas were conducted to ascertain the specific abq subscales with regard to which the three burnout groups differed (table 2). significant (p≤0.013) differences were apparent for the level of mindfulness with regard to reduced sense of accomplishment (abqra; p=0.000), devaluation (abq-d; p=0.002), emotional/physical burnout (abq-e; p=0.011) and total burnout (abq total; p=0.000) (table 2). the corresponding f-values suggested that these results were indicative of large effect sizes with regard to reduced sense of accomplishment (f=0.160) and total burnout (f=0.145), and medium effect sizes with regard to devaluation (f=0.117) and emotional/physical exhaustion (f=0.085). consequently, these findings can be considered to be of moderate to significant practical importance.[18] individuals in the three mindfulness groups thus reported levels of reduced sense of accomplishment, devaluation, physical/emotional exhaustion and total burnout that differed to a statistically and practically significant degree. post hoc comparisons using the scheffé test indicted that the mean abq-ra score for the high fmi group (mean 10.74; sd ±4.09) was significantly lower (p=0.000) than that of the low fmi group (mean 14.61; sd ±2.95). similarly, the mean abq-d score for the high fmi group (mean 9.88; sd ±6.19) was significantly lower (p=0.005) than that of the low fmi group (mean 14.22; sd ±5.16). furthermore, the mean abq total score for the low fmi group (mean 42.22; sd ±10.53) was significantly higher than the mean abq total scores of both the moderate fmi (mean 33.76; sd ±10.23; p=0.008) and high fmi (mean 30.93; sd ±14.56; p=0.001) groups. the abq total means for the high and moderate fmi groups, however, did not differ significantly. no significant differences were found between the three mindfulness groups with regard to their mean abq-e scores. discussion the results of the current study indicate that mindfulness is significantly and inversely related to physical and emotional exhaustion, a reduced sense of sporting accomplishment, sport devaluation and global athletic burnout among competitive adolescent tennis players. high levels of mindfulness are thus associated with lower levels of burnout in this group of athletes. these findings appear to be in keeping with much of the existing literature on mindfulness in sport.[14] higher levels of mindfulness have also been associated with increased focus, more vivid imagery and improved sporting performance.[11,19] mindfulness would thus appear to be related to a number of favourable outcomes among athletes, including reduced burnout symptomatology. it could be hypothesised from a theoretical perspective that by maintaining an open and non-judgemental orientation towards their experiences in the present moment, athletes with higher levels of mindfulness are less likely to engage in critical self-evaluation or repetitive thought processes often associated with increased emotional distress and reduced satisfaction with their general level of sporting achievement.[1,2,7] the results of the anovas revealed that adolescent tennis players reporting different levels of mindfulness also reported differing levels of burnout. more specifically, the high mindfulness participants reported significantly lower burnout than the moderate and low mindfulness participants. adolescent tennis players displaying low table 2. means, sds and f-values for the one-way analysis of variance (anova) for the three levels of mindfulness abq scale high fmi mean (±sd) moderate fmi mean (±sd) low fmi mean (±sd) f-value p-value f-value abq-ra 10.74 (±4.09) 12.68 (±3.48) 14.61 (±2.95) 9.605* 0.000 0.160 abq-d 9.88 (±6.19) 10.78 (±4.30) 14.22 (±5.16) 6.664* 0.002 0.117 abq-e 10.30 (±6.02) 10.29 (±4.25) 13.39 (±4.66) 4.692* 0.011 0.085 total 30.93 (±14.56) 33.76 (±10.23) 42.22 (±10.53) 8.538* 0.000 0.145 abq = athlete burnout questionnaire; abq-ra = abq reduced accomplishment; abq-d = abq devaluation; abq-e = abq emotional/physical exhaustion; total = abq total score. *p≤0.013. 108 sajsm vol. 25 no. 4 2013 levels of mindfulness reported a significantly higher sense of reduced sporting accomplishment and significantly higher sport devaluation than those with high levels of mindfulness. as noted earlier, an increased tendency to engage in critical self-evaluation and rumination with regard to the pace of their sporting progress may incline low mindfulness athletes towards a reduced sense of accomplishment and consequent devaluation of their sport participation. adolescent tennis players reporting low levels of mindfulness were also found to have significantly higher global athlete burnout scores than the moderate and high mindfulness participants. the tentative conclusions that could be drawn from these findings are that not only may higher levels of mindfulness be desirable due to an inverse relationship with burnout, but lower levels of mindfulness may be undesirable due to a significantly stronger association with global burnout than with moderate or high levels of mindfulness. no significant differences were found between the three mindfulness groups concerning physical and emotional exhaustion. this may be indicative of the phase of the playing careers in which the participants currently find themselves. it is possible that physical and mental exhaustion are not prominent burnout symptoms among adolescents who are still developing technically as athletes. the prominent areas of focus, and thus also the most probable areas of burnout presentation, may be related more to issues of developing technical competence, reaching certain performance goals and viewing one’s level of achievement positively in comparison to that of one’s peers.[1,2] consequently, individuals in this phase of their athletic development may be more inclined to experience burnout in terms of a reduced sense of accomplishment and sport devaluation than in terms of physical and emotional exhaustion. study limitations this research is not without limitations. first, a cross-sectional correlational design was employed, thus no conclusions can be drawn regarding possible causal relationships between mindfulness and burnout. future longitudinal and intervention-based research would be valuable in establishing the causal nature of the relationship between these two variables. more sophisticated models should be developed to establish the pathways of causality between mindfulness and burnout, as well as the possible role of other cognitive and emotional mechanisms in the experience of burnout among adolescent athletes. second, the study made use of a homogenous and relatively small sample. the findings can thus not be generalised beyond the current sample. third, athletes in the current sample did not display particularly high levels of global burnout (mean score 23.25). consequently, the results cannot be generalised to athletes exhibiting high levels of burnout. future research would do well to focus specifically on athletes reporting high levels of burnout, as well as on individuals who have withdrawn from competitive sport due to burnout. finally, the fmi is generally employed to measure mindfulness among adults. consequently, this measure may not provide as valid a measure of mindfulness among adolescents. future studies employing more adolescentand sportspecific measures of mindfulness appear to be warranted. conclusion while largely exploratory in nature, this study highlighted the association between mindfulness and burnout among adolescent tennis players. it would appear that adolescent tennis players with high levels of mindfulness are inclined to report significantly fewer symptoms of burnout than those with low levels of mindfulness. further, those players reporting low levels of mindfulness appear to be significantly more inclined to experience a reduced sense of accomplishment with regard to their sporting pursuits, and are more inclined to devalue their sport participation. notwithstanding the limitations of the current study and the obvious need for further research, there would appear to be merit in promoting mindfulness among adolescent athletes. coaches and performance consultants should consider introducing mindfulness interventions as a means of reducing burnout risk in this population. acknowledgements. the author is indebted to ms hanli du toit for her assistance with data collection and prof. karel esterhuyse for his comments on earlier drafts of this manuscript. references 1. fraser-thomas j, côté j, deakin j. understanding dropout and prolonged engagement in adolescent competitive sport. psychol sport exerc 2008;9(5):645-662. [http://dx.doi.org/ 10.1016/j.psychsport.2007.08.003] 2. harris bs, watson jc. assessing youth sport burnout: a self-determination and identity development perspective. j clin sport psychol 2011;5(2):117-133. 3. gustafsson h, kenttä g, hassmén p, lundqvist c. prevalence of burnout in competitive adolescent athletes. sport psychologist 2007;21(1):21-37. 4. raedeke td, smith al. development and preliminary validation of an athlete burnout measure. j sport exerc psychol 2001;23(4):281-306. 5. gustafsson h, kenttä g, hassmén p. athlete burnout: an integrated model and future research directions. int rev sport exerc psychol 2011;4(1):3-24. [http://dx.doi. org/10.180/1750984x.210.541927] 6. goodger k, gorely t, lavallee d, harwood c. burnout in sport: a systematic review. sport psychologist 2007;21(2):127-151. 7. baer ra. mindfulness training as a clinical intervention: a conceptual and empirical review. clin psychol sci prac 2003;10(2):125-143. [http://dx.doi.org/10.1093/clipsy. bpg016] 8. carmody j, baer ra. relationships between mindfulness practice and levels of mindfulness, medical and psychological symptoms and well-being in a mindfulness-based stress reduction program. j behav med 2008;31(1):23-33. [http://dx.doi.org/10.1007/ s10865-007-9130-7] 9. arch jj, ayers cr, baker a, et al. randomized clinical trial of adapted mindfulnessbased stress reduction versus group cognitive behavioural therapy for heterogeneous anxiety disorders. behav res ther 2013;51(4-5):185-196. [http://dx.doi.org/10.1016/j. brat.2013.01.003] 10. cassidy el, atherton rj, robertson n, walsh da, gillet r. mindfulness, functioning and catastrophizing after multidisciplinary pain management for chronic low back pain. pain 2012;153(3):644-650. [http://dx.doi.org/10.1016/j.pain.2011.11.027] 11. ulmer cs, stetson ba, salmo pg. mindfulness and acceptance are associated with exercise maintenance in ymca exercisers. behav res ther 2010;48(8):805-809. [http:// dx.doi.org/10.1016/j.brat.2010.04.009] 12. aherne c, moran ap, lonsdale c. the effect of mindfulness training on athletes’ flow: an initial investigation. sport psychologist 2011;25(2):177-189. 13. schwanhausser l. application of the mindfulness-acceptance-commitment (mac) protocol with an adolescent springboard diver. j clin sport psychol 2009;3(4):377-395. 14. jouper j, gustafsson h. mindful recovery: a case study of a burned out elite shooter. sport psychologist 2013;27(1):92-102. 15. kohls n, sauer s, walach h. facets of mindfulness – results of an online study investigating the freiburg mindfulness inventory. pers indv diff 2009;46(2):224-230. [http://dx.doi. org/10.1016/j.paid.2008.10.009] 16. brislin rw. back-translation for cross-cultural research. j cross-cultural res 1970;1(3):185-216. 17. foster jj, parker i. carrying out investigations in psychology: methods and statistics. leicester: the british psychological society, 1999. 18. cohen j. statistical power analysis for the behavioural sciences. 2nd ed. new york: academic press, 1988. 19. thompson rw, kaufman ka, de petrillo la, glass cr, arnkoff db. one year followup of mindful sport performance enhancement (mspe) with archers, golfers and runners. j clin sport psychol 2011;5(2):99-116. 1. true (a) or false (b) – click on the correct answer: managing chronic diseases of lifestyle falls beyond the scope of practice of biokinetics. 2. true (a) or false (b) – click on the correct answer: in developed countries, physical inactivity is associated with less than 7% of deaths. 3. true (a) or false (b) – click on the correct answer: approximately 500 new biokineticists are trained each year in south africa. 4. true (a) or false (b) – click on the correct answer: less than 5% of south africans with a monthly income above r2 785 utilise primary health care. 5. true (a) or false (b) – click on the correct answer: there is no further capacity for using exercise as a modality to treat chronic diseases of lifestyle in the private health care sector of south africa. 6. true (a) or false (b) – click on the correct answer: although athletes with spinal cord injuries thermoregulate in a similar manner to able-bodied athletes, they tend to store slightly more heat. 7. true (a) or false (b) – click on the correct answer: three days of repeated endurance sub-maximal mountain biking disrupts the sleep of the mountain bikers on the third night of cycling. 8. true (a) or false (b) – click on the correct answer: variables such as age, gender, body mass and fitness all influence the relationship between exercise and sleep. 9. true (a) or false (b) – click on the correct answer: actigraphy is the gold standard method for measuring quality of sleep. 10. true (a) or false (b) – click on the correct answer: objective and subjective measures of sleep quality are similar, therefore it is not necessary to use both methods in research with quality of sleep as an outcome measure. 11. true (a) or false (b) – click on the correct answer: because muscle glycogen is the main fuel during intense exercise, replenishing muscle glycogen stores in the post-exercise period is an important factor influencing recovery and performance. 12. true (a) or false (b) – click on the correct answer: muscle glycogen resynthesis is accelerated for up to 24 hours after exercise. 13. true (a) or false (b) – click on the correct answer: after a glycogen-depleting bout of exercise, glycogen resynthesis occurs in two phases. the first of these phases is dependent on the presence of insulin. 14. true (a) or false (b) – click on the correct answer: a recovery meal consumed within 2 hours after exercise is more effective for improving recovery than no feeding. 15. true (a) or false (b) – click on the correct answer: protein contributes an estimated 40% of total energy expenditure during endurance exercise. 16. true (a) or false (b) – click on the correct answer: plain yoghurt is an effective, but lower-cost, recovery aid due to a cho:pro ratio which is similar to many commercial recovery and carbohydrate-replacement beverages. 17. true (a) or false (b) – click on the correct answer: although research studies suggest that post-exercise recovery beverages containing protein seem to be effective in improving recovery indices, it may be argued that some of the results may be attributed to the higher caloric content of the cho:pro supplements. 18. true (a) or false (b) – click on the correct answer: patients with peripheral arterial disease should avoid exercise. 19. true (a) or false (b) – click on the correct answer: patients with peripheral vascular disease and control patients have similar concentrations of circulating lactate in skeletal muscle coinciding with maximal exercise capacity. 20. true (a) or false (b) – click on the correct answer: reporting a ‘mean’ response following an intervention may fail to convey the individual variation which exists in a group. this may result in misleading interpretation of the intervention. questions march 2011 c p d q u e s t io n n a ir e cpd questionnaires must be completed online via www.cpdjournals.org.za. after submission you can check the answers and print your certificate. questions may be answered up to 6 months after publication of each issue. instructions 1. read the journal. all the answers will be found there. 2. go to www.cpdjournals.org.za to answer questions. accreditation number: mdb001/008/01/2011 (clinical) sajsm sasma views disorders of sexual development (dsd) as a medical condition that has profound physical and psychological effects on not only the individuals affected, but also their families. like any other disorder, this condition has to be managed with a view to offer the best outcomes for affected individuals. when the attending physician identifies stigmata suggesting dsd in a newborn there should be proper consultation and education of parents. challenges in managing dsd include the following: 1. many of these children are born at home in rural areas and subsequently may not access formal medical structures where the dsd can be detected and managed. 2. in this situation where the dsd is not detected the parent/s will decide on the gender; they usually assign a female gender. 3. issues of sexuality are often not discussed within families until puberty, which is when the different traits start showing. 4. there is limited knowledge of dsd in the population, and some individuals will only be diagnosed in adulthood when they encounter problems with sexuality or infertility. in a sporting environment however, these individuals will stand out earlier, particularly if they were raised as girls and develop masculine features. the south african sports medicine association re-iterates the following ethical considerations for practitioners dealing with individuals with dsd: • adherence to strict confidentiality in any medical consultations • the necessity to obtain fully informed, written consent for any investigations • cross-referral within a specialised team consisting of • gynaecologist/s • endocrinologist/s • urologist/s • psychologist/s • physician/s • complete disclosure of information and education of the affected individual regarding the implications of both performing the tests and the findings thereof. further participation in sports will be determined by the diagnosis reached, management of the condition with informed consent from the individuals, and guidelines given by the sporting bodies. strategies should be implemented to address dsd in athletes before they achieve a high profile and compete internationally. this approach may help avoid humiliation and exposure of their intimate details to the public. the following strategy is recommended: • education rollout at schools, sporting bodies, clinics and the public via media and/or formal education. • nursing staff at clinics to be educated to observe and advise parents, and refer for specialised opinion. • coaches and teachers, who are usually the first contact with talented athletic children, to be educated on the sensitivity of this problem, and how to refer for proper management. • all athletes who start competitive international sports from u17 iaaf level meets should have a medical and sexual health screening by a physician (preferably of the same gender). this should not be an invasive examination, but the physician should know the stigmata to look for. any suspected cases of dsd can then be identified and examined more thoroughly. • fully informed consent from athlete and parents/guardians in the under-age athlete to be obtained. • extensive psychological support to be given to the athlete and his/her family. a concern with this approach might be that athletes who already suspect that they are different, may withdraw from competition to avoid the examination. in order to pre-empt and overcome this, prior education on the rules of sporting bodies and an emphasis on confidentiality of all medical findings is important. in particular it should be emphasised that the aim of the medical strategy is to identify and manage conditions so that the athlete can continue with sport. sasma, as the national umbrella body for sports medicine, commits itself within the bounds of medical ethics and sound clinical practice, to co-operate with other national representative sports bodies for the benefit of the health of south african athletes. sasma executive committee august 2010 policy statement south african sports medicine association (sasma) consensus statement on policy for managing athletes with disorders of sexual development (dsd) sajsm vol 22 no. 3 2010 69 km_c227-20180517092651 original research 1 sajsm vol. 30 no. 1 2018 physical demands analysis of soccer players during the extra-time periods of the uefa euro 2016 a kubayi, dphil; a toriola, phd department of sport, rehabilitation and dental sciences, faculty of science, tshwane university of technology, pretoria, south africa corresponding author: a kubayi (kubayina@tut.ac.za) a soccer match is played by two teams, each consisting of 10 outfield players and a goalkeeper. coaches are only allowed to make three substitutions during a game – for injured players or for tactical reasons. the regulation time for a soccer match is 90 minutes, consisting of two halves of 45 minutes each, with a 15-minute half-time break. typically, one to three minutes of referee’s optional time or longer are added to each half to allow for recovery of time lost either to injury or for prolonged disruption of the game during normal regulation time. during the knockout stages of soccer matches, the game is extended by 30 minutes of extra-time (et) if neither side has secured a decisive victory within the normal 90-minute regulation period. [1-4] between 1986 and 2014, 35% of fifa world cup matches in the knockout stages required et. [2] the need for et in soccer tournaments is becoming more common, for example, 50% of knockout matches at the 2014 fifa world cup required 120 minutes of match play compared to 25% at the 2002 and 2010 fifa world cup tournaments respectively, as well as 38% at the 2006 fifa world cup. [2] however, the physical demands of et on elite soccer players have rarely been studied. this is somewhat surprising considering the role of this additional period of play in determining success in soccer tournaments. [3] to date, two studies were conducted by lago-peñas et al. [4] and russell et al. [5] who focused on the impact of the et period on physical performance in professional soccer. these studies concluded that the total distance covered high-intensity running, maximal running speed and the number of sprints were reduced in et compared to the first and second halves of the matches. despite the novelty of the information provided by these studies, [4, 5] there is scant evidence for the physical demands of soccer players during the et period, especially in a popular tournament such as the uefa euro. therefore, research is clearly needed in this regard because the uefa euro is one of the most important tournaments in world soccer; for example, four out of the last five fifa world cup competitions were won by european teams. [6] furthermore, a better understanding of the movement demands of the et period could provide information on the tactical preparations and recovery practices of soccer players when matches that require this additional period of competition are either anticipated or have occurred. [5] therefore, the purpose of this study was to analyse the influence of the et period on the physical demands of soccer players during the 2016 uefa euro championship. methods match data and participants the sample consisted of four matches from six teams that went to et during the 2016 uefa euro championship. all players (with the exception of the goalkeepers) who finished the entire 120 minutes of the game were included in the analyses (n=59). players were categorised as follows: central defenders (cds: n=16), wide defenders (wds: n=12), central midfielders (cms: n=10), wide midfielders (wms: n=9) and attackers (ats: n=12). the study received ethical clearance from the ethics committee of tshwane university of technology, south africa. data collection match physical indicators were recorded using the camera tracking system, instat scout video analysis, russia. match data were captured with video cameras, installed in pairs on each of the two main stands of the stadium. the accuracy of the instat tracking system has been reported in a previous study. [7] in addition, the physical indicator variables were categorised as follows: walking (0–7 km/h), jogging (7.1–14.5 km/h), running (14.6–20 km/h), high-speed running (20.1–25 km/h), and sprinting (>25 km/h). total distance represented the summation of distances in all categories. absolute distances (m) were converted to the relative distance covered per unit of time (m/min). [4] background: despite the importance of extra-time (et) in determining success in the knockout stages of tournaments, there is scant information on the physical demands of et on soccer players. methods: this study investigated the physical demands of all soccer players (n=59) who completed four matches that went to et at the 2016 uefa euro championship. players were categorised as follows: central defenders (cds), wide defenders (wds), central midfielders (cms), wide midfielders (wms) and attackers (ats). match activities were captured using a validated camera tracking system (instat®). descriptive statistics and repeated measures one-way analysis of variance (anova) were used to analyse the data. results: the findings showed that total distances covered by players during matches decreased by 13% from the first half of the game (113±10 m/min) to et (98±10 m/min). concerning playing positions, a decline in total distances covered during matches was more apparent among midfielders than players in other field positions. a repeated measures anova, with a greenhouse-geisser correction, showed that the mean total distances differed significantly between halves of the game [f(1.54, 83.28) = 121.97, p < 0.001]. conclusion: intervention strategies needed to sustain soccer players’ physical performance during et periods and of postmatch recovery modalities warrant further investigation. keywords: distance, physical performance, substitution, tournament s afr j sports med 2018;30:1-3. doi: 10.17159/2078-516x/2018/v30i1a4842 mailto:kubayina@tut.ac.za http://dx.doi.org/10.17159/2078-516x/2018/v30i1a4842 original research sajsm vol. 30 no. 1 2018 2 statistical analysis data were expressed as means and standard deviations (m±sd). repeated measures one-way analysis of variance (anova) were conducted on the distances covered in the matches played based on the various playing positions (cd, wd, cm, wm, and at) during the first and second halves, as well as for the et period. bonferroni post-hoc analyses were further carried out to identify which of the distances covered were substantially different, and the significance level was set at 0.05. all statistical analyses were performed using ibm spss software (version 25.0). results table 1 presents the physical demands of players during the first and second halves of the matches as well as the et period. overall, total distances covered by players during the matches decreased by 13% from the first half of the game (113±10 m/min) to et (98±10 m/min). with regard to playing positions, a reduction of total distances covered during the matches was more apparent among the midfielders (wds) than players in other field positions. for example, the total distance covered by the wms was reduced by 17% in the first half of the game (119±10 m/min) to et (99±9 m/min) (table 1). a repeated measures anova, with a greenhouse-geisser correction, showed that the mean total distances differed significantly between the halves of the game [f(1.54, 83.28) = 121.97, p < 0.00]. the reduction of the sprinting distance was greater among ats than other players (i.e. cds, cms, wms, and cms). specifically, the sprinting distance decreased from the first half of the game (3±1 m/min) to the et period (1±1 m/min). a repeated measures anova, with a greenhouse-geisser correction, indicated that the sprinting distance was significant between the halves of the game [f(1.74, 93.96) = 4.25, p < 0.02]. a bonferroni post-hoc test showed that the average sprinting distance for the ats was significantly different from those of the cds, cms, and wds. discussion this study investigated the physical demands of soccer players during the et periods of the 2016 uefa euro championship. the results showed that total distances covered by the players during the matches decreased by 13% from the first half to the et period. this is a faster rate of decline than that reported by russell et al. [5] who stated that the mean distance covered by players reduced by ~10% in the et period compared to the first and second halves. it has been speculated that players who fail to perform the expected work rates in a game may be experiencing a decline in aerobic capability due to fatigue. [8] furthermore, the decrease in the total distance covered during the matches affected all playing positions, a finding which supports that of lago-peñas et al. [4] this reduction was more apparent among midfielders (wds) than defenders. this could be attributed to the longer distances covered by the midfielders in the first and second halves of the matches in the present study, which might have reduced the distances covered during the et period. a greater reduction in high-intensity running (i.e. sprinting) was more evident among the ats than players in other positions. as bradley et al. [9] argued, the ats are required to maintain a high level of activity, even when not directly involved in play, in order to create space to receive passes or to pressurise opponents into making unforced errors. although not ascertained in the current study, previous research has demonstrated that technical skills decrease considerably from the first half of a match to the et period. for example, harper et al. [3] reported that passing performance was reduced by more than 20% during the et when compared to the first half of the game. these findings may suggest that table 1. physical demands of players during first and second halves of the matches as well as extra-time periods all (n= 59) cd (n=16) wd (n= 12) 1st half 2nd half et 1st half 2nd half et 1st half 2nd half et total distance (m/min) 113±10 107±9 98±10 104±6 98±5 91±7 111±3 106±5 99±10 walking (m/min) 37±4 37±4 38±4 38±4 39±4 39±6 38±4 37±3 38±2 jogging (m/min) 46±7 43±6 37±7 43±3 40±5 34±5 43±4 42±5 38±6 running (m/min) 19±5 17±5 15±4 15±4 13±4 12±4 18±3 16±4 14±5 high-speed running (m/min) 9±3 8±3 7±2 7±2 6±2 5±2 10±2 9±3 7±2 sprinting (m/min) 2±3 2±1 1±1 1±1 1±1 1±1 2±1 2.±1 2±1 cm (n=10) wm (n= 9) at (n= 12) 1st half 2nd half et 1st half 2nd half et 1st half 2nd half et total distance (m/min) 118±12 113±9 104±10 119±10 110±8 99±9 115±7 109±7 103±6 walking (m/min) 34±2 34±4 36±3 36±5 36±5 36±4 37±3 38±3 39±4 jogging (m/min) 53±7 48±6 42±7 49±8 44±7 39±7 46±7 43±7 39±7 running (m/min) 23±7 21±5 17±4 23±5 19±4 16±4 19±3 17±2 16±3 high-speed running (m/min) 11±4 9±2 8±2 10±3 10±4 7±3 10±1 9±1 9±2 sprinting (m/min) 1±1 1±1 1±1 1±1 1±1 1±1 3±1 2±0 1±1 data expressed as mean ± sd physical indicator variables were categorised as follows: walking (0–7 km/h), jogging (7.1–14.5 km/h), running (14.6–20 km/h), high-speed running (20.1–25 km/h), and sprinting (>25 km/h). total distance represented the summation of distances in all categories. cd, central defender; wd, wide defender; cm, central midfielder; wm, wide midfielder; at, attacker; et, extra-time original research 3 sajsm vol. 30 no. 1 2018 match-related fatigue had a greater influence on the players’ technical ability to get involved with the ball than on their skill proficiency. [10] thus, soccer coaches and scientists could use the results of this study to inform the current practices in a deeper understanding of the influence of the et on the physical demands of the game and develop intervention strategies to delay the onset of fatigue among players. [2] however, few studies have investigated the influence of matches requiring the et on players’ recovery modalities and subsequent performances in games during congested fixture schedules. [2] conclusion this study found that the physical demands of soccer players, irrespective of their playing position, decreased from the first half to the et period of the matches played. in addition, a reduction of total distances covered during the matches was more apparent among the midfielders than players in other field positions. based on the findings of the current study, soccer governing bodies (e.g. fifa) should consider introducing a fourth substitution for matches that extend to the et. this view is consistent with that of harper et al. [2] which suggested that such a substitution could minimise the effects of fatigue, reduce the risk of load-related injuries and improve player performance. references 1. rey e, lago-ballesteros j, padrón-cabo a. timing and tactical analysis of player substitutions in the uefa champions league. int j perform anal sport 2015; 15(3): 840–850. [doi: 10.1080/24748668.2015.11868835] 2. harper ld, fothergill m, west dj, et al. practitioners’ perceptions of the soccer extra-time period: implications for future research. plos one 2016; 11(7): e0157687. [doi:10.1371/journal.pone.0157687] 3. harper ld, west dj, stevenson e, et al. technical performance reduces during the extra-time period of professional soccer match-play. plos one 2014; 9(10): e110995. [doi:10.1371/journal.pone.0110995] 4. lago peñas c, dellal a, owen al, et al. the influence of the extra-time period on physical performance in elite soccer. int j perform anal sport 2015; 15(3): 830–839. [doi: 10.1080/24748668.2015.11868834] 5. russell m, sparkes w, northeast j, et al. responses to a 120 min reserve team soccer match: a case study focusing on the demands of extra time. j sports sci 2015; 33(20): 2133–2139. [doi: 10.1080/02640414.2015.1064153] 6. winter c, pfeiffer m. tactical metrics that discriminate winning, drawing and losing teams in uefa euro 2012®. j sports sci 2016; 34(6): 486–492. [doi: 10.1080/02640414.2015.1099714] 7. dmitriy a, mike v, ilya v, et al. validation and precision analysis of instat fitness system. instat 2013; 1–14. http://www.instatscout.com 8. carling c, williams a, reilly t. the handbook of soccer match analysis: a systematic approach to improving performance. london: routledge, 2005:95. 9. bradley ps, sheldon w, wooster b, et al. high-intensity running in english fa premier league soccer matches. j sports sci 2009; 27(2): 159–168. [doi: 10.1080/02640410802512775] 10. rampinini e, impellizzeri fm, castagna c, et al. technical performance during soccer matches of the italian serie a league: effect of fatigue and competitive level. j sci med sport 2009; 12(1): 227–233. [doi: 10.1016/j.jsams.2007.10.002] km_c227-20180711130354 1. true (a) or false (b) – click on the correct answer: only 20% of the schoolboys in johannesburg who were surveyed believed that the use of ‘performance-enhancing substances’ was increasing among their peers. 2. true (a) or false (b) – click on the correct answer: according to a survey of schoolboys, most of the information about performance-enhancing substances is obtained from the internet. 3. true (a) or false (b) – click on the correct answer: the south african institute for drug-free sport (saids) is one of the many signatories that complies with the prohibited list of substances of the world anti-doping agency (wada). 4. true (a) or false (b) – click on the correct answer: ‘the pressure to perform in sport’ was the reason given by schoolboys when they were asked why they used performance-enhancing substances. 5. true (a) or false (b) – click on the correct answer: the commonwealth games will be held in delhi (india) in 2010. 6. true (a) or false (b) – click on the correct answer: according to a forecasting study, south africa will get up to 5 gold medals and 62 medals in total at the 2010 commonwealth games. 7. true (a) or false (b) – click on the correct answer: athletics and swimming accounted for 50% of all medals won by south africa in the commonwealth games in melbourne 2006. 8. true (a) or false (b) – click on the correct answer: the magnitude of confidence intervals around calculated injury rates will be artificially narrow if recurrent injuries are not considered in the analysis. 9. true (a) or false (b) – click on the correct answer: genetic factors have been identified as intrinsic risk factors in chronic achilles tendinopathy. 10. true (a) or false (b) – click on the correct answer: studies investigating the interaction between genetic variables and injury do not need to consider age in their research design. 11. true (a) or false (b) – click on the correct answer: sternal stress fractures are common injuries in young gymnasts. 12. true (a) or false (b) – click on the correct answer: forty-five per cent of all stress fractures in gymnasts involve the pars interarticularis, because of considerable stress on the lower back as a result of repetitive flexion, hyperextension, rotation and compressive loading of the spine on landings. 13. true (a) or false (b) – click on the correct answer: the majority of stress fractures in gymnasts occur during competition, rather than during practice. 14. true (a) or false (b) – click on the correct answer: in order to incur health benefits, it is more important to be lean rather than be physically fit. 15. true (a) or false (b) – click on the correct answer: individuals engaging in a standardised, supervised exercise programme have been shown to have very similar adaptive responses. 16. true (a) or false (b) – click on the correct answer: ‘non-responders’ to a 12-week aerobic training programme experienced a statistically significant mean reduction in body weight from week 0 to week 12. 17. true (a) or false (b) – click on the correct answer: exercise-induced improvements in blood pressure have been shown to be least effective in individuals classified as hypertensive at baseline. 18. true (a) or false (b) – click on the correct answer: some individuals may be resistant to exercise-induced weight loss because of strong physiological compensatory processes. 19. true (a) or false (b) – click on the correct answer: waist circumference has been shown to be a better marker of response to exercise than bmi. 20. true (a) or false (b) – click on the correct answer: the physiological and psychological benefits of exercise are dependent on weight loss. questions july 2010 c p d q u e s t io n n a ir e cpd questionnaires must be completed online via www.cpdjournals.org.za. after submission you can check the answers and print your certificate. questions may be answered up to 6 months after publication of each issue. instructions 1. read the journal. all the answers will be found there. 2. go to www.cpdjournals.org.za to answer questions. accreditation number: mdb001/009/01/2010(journal) sajsm sajsm 595 (commentarty).indd sajsm vol. 27 no. 1 2015 3 commentary both the referee and the ringside physician are entrusted with the safety of the boxer in the ring. the uniform boxing rules (approved august 25, 2001, amended august 2, 2002, amended july 3, 2008) recognise the referee as the sole arbiter of a bout and the only individual authorised to stop a contest. unified rules of mixed martial arts (mma) and some boxing commissions recognise both the referee and the ringside physician as arbiters of a fight, and the only individuals authorised to enter the fight area at any time during competition and stop a fight when the combatant’s safety is compromised. irrespective of who stops the fight, the stoppage should be timely and fair to the combatants and their corners; a premature stoppage is unfair to the boxers, their corners, the promoter and the public, while a fight stopped too late risks serious injury and even death of the boxer.[1] stoppage from inside the ring by the referee is accepted by the boxer, his corner staff and the public (present in the arena and the wider television audience) more readily than stoppage from outside the ring by the ringside physician. ringside physicians usually have a lower threshold for stopping a contest compared with the referee. lack of knowledge of a boxer’s punch-taking ability and fear of litigation may lead to premature stoppage of a fight by the ringside physician. ideally, everyone would like the bout to be stopped before a life-threatening or career-ending injury occurs. the keyword here is before not after. however, most of the time this is not possible, so a more realistic goal should be timely identification of a serious injury in the ring and timely stoppage of a fight. for that to occur, the referee should be aware of the signs and symptoms of serious injuries. since a referee’s medical knowledge is limited, he and the ringside doctor need to act as a team. the cause of sudden death in the ring is either cardiac or neurological. cardiac causes are commonly identified by the ringside physician prior to the boxer entering the ring, during the course of the prefight medical check-up, when an electrocardiogram is reviewed and, if needed, an echocardiogram is requested. neurological injuries in the ring are more difficult to determine clinically. epidural haematomas and second-impact syndrome may lead to a walking, talking but dying boxer. referees should be skilled in recognising concussions in the ring, especially of the more subtle grades 1 and 2 when the boxer is ‘out on his feet’, unable to defend himself, looks dazed, staggers around the ring or rests on the rope but does not experience loss of consciousness, is confused, does not remember the round, walks to the wrong corner after the bell or hits out at the referee. the referee should take into consideration the biomechanics of the punch thrown, the rotational and linear acceleration suffered by the skull and the impact deceleration before deciding to let the fight go on.[2] the modified maddocks et al.[3] questions can be quickly and easily administered in the ring by the referee to assess for concussion by asking the boxer questions such as: at what venue are you today? which round is it now? who are you fighting? how many rounds is the fight? if the boxer answers incorrectly, it is best to bring this to the attention of the ringside doctor in between the rounds. the boxer can then be further assessed to determine whether he can safely continue. after a boxer gets up from a knock-out, instead of making the boxer walk straight to him, the referee should ask him to take a few steps forward and then a step to the side to better assess his balance. ideally, a fight should be stopped by the referee after consulting with the ringside physician, after taking into account not just the most recent round but the previous rounds too, as well as the boxer’s and his corner’s body language. good and constant communication between referee and ringside physician is the key. they should talk in between the rounds and share their assessment of the boxer with each other, supplementing each other’s knowledge of medicine and boxing. the boxer’s safety should always precede all other considerations. references 1. miele vj, bailes je. objectifying when to halt a boxing match: a video analysis of fatalities. neurosurgery 2007;60(2):307-316. [http://dx.doi.org/10.1227/01. neu.0000249247.48299.5b] 2. stemper bd, pintar fa. biomechanics of concussion. prog neurol surg 2014;28:14-27. [http://dx.doi.org/10.1159/000358748] 3. maddocks dl, dicker gd, saling mm. the assessment of orientation following concussion in athletes. clin j sport med 1995;5(1):32-35. s afr j sports med 2015;27(1):3. doi:10.7196/sajsm.595 boxer safety, and the relationship between the referee and the ringside physician n k sethi, md, mbbs, faan department of neurology, new york presbyterian hospital, weill cornell medical center, new york, usa corresponding author: n k sethi (sethinitinmd@hotmail.com) 62 sajsm vol. 27 no. 3 2015 over diagnosing? time for the ‘exercise is medicine’ movement to react clinical medicine has been overdiagnosing for several years; sport and exercise medicine needs to guard against falling into the same trap. this was the message portrayed in a podcast in which dr karim khan, editor of the british journal of sports medicine, interviewed ray moynihan,[1] one of the authors of the bestselling book selling sickness: how the world’s biggest pharmaceutical companies are turning us all into patients.[2] the concept of ‘selling sickness’ is becoming a major public health problem, with many patients being treated for diseases or injuries that do not require treatment. often the treatment has more undesirable effects than no treatment at all. the driving force for overdiagnosing can have different origins. the most common origin can be attributed to profit, particularly if the condition needs medication, or expensive diagnostic procedures. another driving force can be academic/clinical status; a clinician develops a reputation for being able to make an unusual diagnosis, and this behaviour seems to attract more unsuspecting patients. it does not take long for a condition to become fashionable. consider, for example, the rather sudden increase in the number of patients getting diagnosed with conditions that used to be rare (chronic fatigue syndrome, irritable bowel syndrome, attention deficit hyperactivity disorder in children, to name a few). in the discipline of sport and exercise medicine, there are signs that overdiagnosing is becoming more mainstream. the number of referrals for a magnetic resonance imaging (mri) diagnosis has increased precipitously. while it is accepted that elite professional sports participants need the best medical care to diagnose an injury, it is questionable whether a recreational athlete needs to incur the same expenses for a rather innocuous injury. while mris can identify structural abnormalities, these structural abnormalities may not be associated with pain or degeneration. there are many unanswered questions about the association between structural abnormalities, injury and degeneration. this raises the question of ‘what is normal?’ this is an important question, because the distinction between normality and abnormality forms the basis of medical practice. [3] according to this paradigm, if a condition is abnormal, it needs to be treated; if it is normal, it can be left alone. differentiating between normal v. abnormal is not as simple as it may initially seem. for example, is it appropriate for age-associated conditions to be regarded as abnormal? should 50-year-old men and women be prescribed hormone replacement therapy because they no longer have the same endocrine profile as someone in their twenties? for the definition of normal to be applied appropriately, genderand age-based comparisons should be made; failure to do so opens opportunities for overdiagnosing. a caveat to this argument is that at some point, age-related changes are no longer considered normal. for example, the prevalence of sarcopenia and osteoarthritis increase with age and are regarded as a natural part of the ageing process. therefore, one can argue that within a group of 80-year-olds, it is normal to have sarcopenia and osteoarthritis. but should they be regarded as normal and left untreated?[4] or should they all be placed on medication to reduce these effects? if the definition of normal v. abnormal is precise and indisputable, the chances of overdiagnosing will diminish. a murky definition provides fertile ground for practitioners prone to overdiagnose. this area of indecision is where the pharmaceutical companies have taken the initiative and generated an industry providing a variety of medications to counter the consequences of ageing. it is an easy marketing exercise to prescribe a pill for a condition. compare this with trying to encourage a person to become more physically active. even in the presence of an overwhelming amount of evidence supporting the positive role of physical activity in treating and managing many of the conditions associated with increasing age, the task of getting people to become more physically active is daunting. it is going to take much marketing and canvassing to convince the public that there are alternative options to medication to counter the natural consequences of ageing. this message is encompassed in the vision of the ‘exercise is medicine’ movement.[5] they have a tough job ahead to make a case against overdiagnosing and treating ailments, particularly those conditions that occur as a consequence of getting old. 1. bmj talk medicine. ‘overdiagnosis’ in sports medicine? fai for example? the great ray moynihan (‘selling sickness’). https://soundcloud.com/bmjpodcasts/ overdiagnosis-in-sports-medicine-fai-for-example-the-great-ray-moynihan-sellingsickness (accessed 20 august 2015). 2. moynihan r, cassels a. selling sickness: how the world’s biggest pharmaceutical companies are turning us all into patients. sydney: allen and unwin, 2005. 3. ko eslag jh. what is normal? s af r med j 1993;83(1):47-50. 4. baldwin jn, mckay mj, hiller ce, et al. forming norms: informing diagnosis and management in sports medicine. british journal of sports medicine 2015. http://doi.org/10.1136/bjsports-2014-094489 5. exercise is medicine. http://www.exerciseismedicine. org (accessed 20 august 2015). mike lambert editor-in-chief s afr j sports med 2015;27(3):62. doi:10.7196/sajsm.8769 editorial original research 20 sajsm vol. 26 no. 1 2014 background. by incorporating pre-performance or retrospective recall measurement methods, research has shown positive (pa) and negative affect (na) to operate as both a precursor to, and as a consequence of performance in line with goal achievement. the extent of this affective change within sport is unclear, as measurement of affect within acute settings has yet to be adopted fully. objective. to conduct exploratory research examining affect and goal achievement during self-paced cycling to understand further their role during performance. methods. the positive and negative affect schedule (panas), worcester affect scale (was) and ratings of goal achievement were completed by seven trained cyclists prior to two separate 20 km laboratory time trials. the was and ratings of goal achievement were also rated during each trial. results. micro-oscillations in affect occurred throughout time trials and to a greater degree where participants were unsuccessful in reaching their goals. successful trials were characterised by higher pa (p=0.000) and lower na (p=0.000), with higher goal expectations from the start (p=0.008). conclusion. in unsuccessful trials, an overly aggressive start, perhaps due to inaccurate goal setting, led to an inability to maintain performance, with reductions in power output. further clarification of the catalyst to the performance demise requires a parallel analysis of psychological and physiological parameters. in so doing, a greater understanding of the combined role of affect and goal expectation in pacing and performance will ensue; a benefit to both cyclist and coach alike. s afr j sm 2014;26(1):20-25. doi:10.7196/sajsm.496 micro-oscillations in positive and negative affect during competitive laboratory cycle time trials – a preliminary study c rhoden,1 phd; j west,1 msc; a renfree,1 msc; m corbett,1 phd; a st clair gibson,1,2 phd, md 1 institute of sport and exercise sciences, university of worcester, henwick grove, worcester, united kingdom 2 school of life sciences, northumbria university, northumberland building, newcastle upon tyne, united kingdom corresponding author: c rhoden (c.rhoden@worc.ac.uk) watson[1] postulated a hierarchical structure of affect with two broad dimensions of positive (pa) and negative affect (na), reflecting the overall valence of affect in an individual at the higher order level. a lower order level reflects the specific states of mood and emotion experienced by individuals.[2,3] watson[1] emphasised the notion of a stream of affect, where individuals are continuously experiencing some type of mood. considering the cyclical nature of moods, he suggested that variables which occur irregularly over time (e.g. exercise) would give rise to unevenly distributed mood fluctuations in comparison to endogenous factors (e.g. the circadian variation in mood). changes in affect and mood have been observed in both sport and exercise settings,[3,4] revealing the association between affect and performance, success and achievement. in a novel throwing task, na was significantly higher in failure when compared with successful conditions.[6] pa predicted performance and was also related to self-efficacy in high school wrestling competitions.[7] more recently, pa was positively correlated to elite climbers’ route score.[5] these studies assessed affect at a macro level (pre-performance). we feel that it is also important to consider fluctuations or oscillations in affect at a micro level (within performance), yet this has received limited attention to date and within an exercise setting only.[4] goal expectations are also pertinent to the understanding of affective responses in sport. in self-regulation theory, monitoring of selfand norm-referenced information enables individuals to make necessary adjustments to minimise the discrepancy between desired and actual behaviour.[8] a second parallel feedback system, the meta-monitoring function, identifies whether discrepancies are positive, negative or nonexistent,[8] and subsequent affective states ensue. progress towards a goal at a higher rate than expected (positive discrepancy) leads to pa, and conversely, slower than expected progress (negative discrepancy) leads to increased na. affect changes originating from goal progress interpretation have been shown empirically. where golfers’ actual performance was lower than their goals during a tournament, higher na and lower pa were experienced,[9] though the measurement of affect was undertaken only once and by retrospective recall. unexpected increases in exercise duration caused runners to become suddenly and significantly more negative,[10] while the negative effects of a psychological crisis (characterised by thoughts about goal disengagement) peaked three-quarters of the way through a marathon and had a negative impact on race performance.[11] consequently, an individual’s perception of likely success while an activity is ongoing becomes an important construct to understand and examine. moreover, highlighting the role of affective responses and motivation on mailto:c.rhoden@worc.ac.uk sajsm vol. 26 no. 1 2014 21 pacing and performance, baron et al.[12] proposed that athletes would be more likely to maintain or increase exercise intensity when pa was experienced. where na was experienced, athletes would have less desire to sustain exercise intensity and a reduction in performance may result. this suggested relationship has obvious implications for time trial performance at the micro level. affect operates both as a precursor to, and as a consequence of performance, with actual performance, perceived achievement, success and failure playing additional roles.[5,6] differing affective experiences may augment or diminish an individual’s effort and exercise intensity. consequently, we sought to examine the relationships between affect, goal expectation and performance by extending previous research protocols to measure affect in parallel with performance measures of time and power output.[5,9] a repeated measures design enabled us to manipulate the analysis of data via the performance outcome, and compare affect profiles between success and failure conditions. objectives we aimed, via an exploratory research approach: (i) to explore whether micro-oscillations in affect would occur during a competitive time trial environ ment; and (ii) to assess affect, goal expectations and performance (time and power output) between successful (where cyclists achieved a time goal) and unsuccessful (where cyclists did not achieve a time goal) time trials. methods participants in an experimental, laboratory-based investigation, seven well-trained cyclists (six males, one female; mean ± standard deviation (sd) age 32.6±11.5 years) performed two 20 km time trials. participants were local, competitive club cyclists or triathletes (minimum 2 years’ time trial experience). participants were familiar with 20 km time trials and regularly paced themselves over this and other distances, enabling us to reproduce a realistic, albeit laboratory, time trial environment. participants’ age, height, weight and 20 km time trial personal best times did not differ between the successful and unsuccessful groups (table 1). prior to testing, participants completed health screening forms and provided full, written, informed consent. all study procedures received institutional ethics committee approval. measures panas the positive and negative affect schedule (panas)[13] was used to assess pa and na 30 min before the time trial. using a five-point likert scale from 0 (not at all) to 4 (extremely), participants rated their current responses to ten positive and ten negative adjectives. internal reliability was demonstrated with a good α-coefficient for pa (0.89) and an acceptable α-coefficient for na (0.73). worcester affect scale the worcester affect scale (was)[14] was used to measure pa and na at 0.5 km intervals during the time trial, taking 5 10 s to complete. participants rated how they felt ‘right now’ on two separate ten-point likert scales: pa (1 – not at all positive; 10 – extremely positive) and na (1 – not at all negative; 10 – extremely negative). preliminary validation indicated the was to be related to the panas and sensitive in assessing changes in affect during self-paced exercise.[14] goal expectancy thirty min prior to each trial, participants were asked to identify a time goal based on previous performances and to rate the extent to which they felt they could achieve this goal on a newly created tenpoint likert scale (1 – not at all; 10 – very much so). using the same rating scale, participants provided ratings of goal expectancy during the trial at 5, 10 and 15 km of the total distance. at 20 km, using the same rating scale, participants rated their achievement of goal expectations. procedure participants completed two 20 km time trials, separated by a mean±sd of 5.5±1.9 days, approaching each time trial as if it were a minor competition to standardise training and nutritional strategies. all participants regularly used the ergometer rig (kingcycle ltd, uk) for training purposes and were familiar with the time trial distance in this study; as such, we considered a familiarisation trial unnecessary. at each visit to the laboratory, participants were instructed to ‘ ... complete the time trial in as fast a time as possible’. participants recorded their goal for the time trial, provided a goal expectancy rating and then completed the panas and was. using their own bicycle mounted and calibrated on the ergometer rig, participants were allowed to view performance feedback: speed, time, power and heart rate. after a self-selected warm-up, comparable with the duration and intensity of their normal pre-time trial routine, participants were given a 5-second countdown. pa and na were recorded every 0.5 km using the was scales, which were alternated to ensure that no order effects prevailed. instantaneous power output (w) was recorded visually every 0.5 km throughout, while ratings of goal expectancy were recorded at 5, 10 and 15 km during the time trial. goal achievement and performance time was recorded upon completion of the 20 km. this protocol was the same for both trial 1 and trial 2. table 1. demographics of the successful and unsuccessful groups group n age (years) mean±sd height (m) mean±sd weight (kg) mean±sd 20 km time trial pb (s) mean±sd successful 4 29±12 1.85±0.07 74.75±9.18 1 963.50±149.38 unsuccessful 3 34±14 1.79±0.05 76.83±2.84 1 739.33±82.25 p-value 0.642 0.286 0.725 0.069 sd = standard deviation; pb = personal best. 22 sajsm vol. 26 no. 1 2014 data analysis in this study we undertook psychological examination of a dataset previously published. renfree et al.[15] analysed the complex interplay between determinants of pacing and performance, and rhoden and west[14] provided a preliminary validation of the was. the current analysis examined affect, goal expectancies and performance be tween successful and unsuccessful participants in trial 2 only. prior to the second time trial, all participants reported a time goal, which was to beat their previous time; as such, the expected time goal for trial 2 was anticipated to be less than or equal to the trial 1 performance time. hence, 100 1 2 3 4 5 6 7 8 9 10 5 10 15 20 a 1 2 3 4 5 6 7 8 9 10 5 10 15 20 d median for trial 1 trial 2 pa 1 2 3 4 5 6 7 8 9 10 5 10 15 20 b 1 2 3 4 5 6 7 8 9 10 5 10 15 20 e median for trial 1 trial 2 na 100 150 200 250 300 350 400 450 500 5 10 15 20 po w er (w ) c 5 10 15 20 f trial 1 trial 2 po w er (w ) 150 200 250 300 350 400 450 500 time trial distance (km) time trial distance (km) unsuccessful participants successful participants n eg at iv e a� ec t ( m ed ia n va lu es ) n eg at iv e a� ec t ( m ed ia n va lu es ) po si ti ve a � ec t ( m ed ia n va lu es ) po si ti ve a � ec t ( m ed ia n va lu es ) fig. 1. worcester affect scale (was) median scores and power outputs during the time trial: (a c) participants who were unsuccessful (n=3) and (d f ) participants who were successful (n=4) in trial 2. for (c) and (f ), mean ± standard deviation (sd) power output is displayed; (*p<0.000; pa = positive affect; na = negative affect.) sajsm vol. 26 no. 1 2014 23 successful participants were categorised as those who achieved their goal, completing the time trial in the same time as, or faster than their previous time. unsuccessful participants did not achieve their goal, performing slower than in trial 1. performance time and power were assessed using paired t-tests; however, where distribution curves were non-normal, non-parametric wilcoxon tests were applied. mean±sd values were used for graphical representation. affect and goal expectancy were analysed using non-parametric statistics (mann-whitney u-test, wilcoxon test and spearman rank correlation test). median values were used for graphical representation. results based on time goals (less than or equal to previous time in trial 1 for all participants), the expected mean±sd performance time for the successful and unsuccessful groups was ≤1 958.50±175.43 s and ≤1 685.33±25.74 s, respectively. the successful group met their goal expectations, with signifi cantly improved performance times evident in trial 2 (mean±sd 1 880.00±160.43 s; improvement 79±15 s; t=5.08; p=0.015; η2=0.89; n=4). actual performance times differed from expected times for the unsuccessful participants, who achieved a slower (although not significantly) time in trial 2 (mean±sd 1 723.33±10.60 s; deterioration -38±15 s; n=3). pa and na micro-oscillations occurred throughout the duration of the trials for all participants, and to a greater degree in trial 2 for unsuccessful participants. unsuccessful participants had lower levels of pa from the outset of the time trial and, in contrast to successful participants, became progressively less positive during the first two-thirds of the time trial (u=0.0; w=820.0; z= 8.0; p=0.000; r=0.89; fig. 1a). they had higher levels of na from the outset than successful participants (u=44.0; w=864.0; z=-7.55; p=0.000; r=0.84), which peaked at 15 km (fig. 1b). furthermore, unsuccessful participants experienced greater fluctuations in the frequency and magnitude of pa between 10 km and 17 km than successful participants (figs 1a and d). na also varied con sider ably for cyclists in the unsuccessful group, with many micro-oscillations again occurring at 12 19 km (fig. 1b). for successful participants, small, periodic fluctuations in na occurred during the time trial, with a decrease in negativity from 17 km onwards (fig. 1e). pre-trial panas scores replicated the pre-trial was scores, with unsuccessful participants reporting significantly higher na (median 7) 30 min prior to the start of the time trial than successful participants (median 3; u=0.0; w=10.0; z=-2.14; p=0.032; r=0.25), and lower (but not significantly) pa (unsuccessful athletes: median 24; successful athletes: median 32). significant differences were observed in the goal expectancies of successful v. unsuccessful cyclists (u=0.0; w=15.0; z=-2.65; p=0.008; r=0.84; fig. 2). goal expectancy was lower from the outset of the trial for unsuccessful participants, which subsequently decreased compared with the successful participants’ ratings. goal expectancy was consistently positively correlated with pa at 5, 10 and 15 km, and negatively correlated with na at 5 km through the time trials (table 2). power output was significantly different between trial 1 and trial 2 for the unsuccessful participants (t=5.09; p=0.000; η2=0.39; fig. 1 2 3 4 5 r at in g o f g ao al e xp ec ta n cy successful unsuccessful 6 7 8 9 10 pre 5 10 15 post time trial distance (km) fig. 2. ratings of goal expectancy (median scores) between the successful and unsuccessful participants in trial 2 only. table 2. spearman rank order correlations between the was and goal expectancy ratings during the time trials goal expectancy time trial 5 km 10 km 15 km pa rho p-value 0.68 0.007 0.79 0.001 0.69 0.006 na rho p-value -0.56 0.038 -0.28 0.316 -0.47 0.094 was = worcester affect scale; pa = positive affect; na = negative affect. 24 sajsm vol. 26 no. 1 2014 1c). they started their slower unsuccessful trial (trial 2) with a higher power output. after 6.5 km there was a reduction in power output, which remained lower than in their first trial for the remainder of the trial (fig. 1c). immediately prior to this point, these participants reported a decrease in pa and an increase in na (3 5 km) (figs 1a and b). large oscillations in pa and na accompanied the continual decrease in power output over the second half of the time trial. in both trials, participants produced an end spurt of similar magnitude (~70 w increase) over the last 2.5 km, although actual power was reduced in trial 2 compared with trial 1. when comparing trial 1 and 2 for successful participants (fig. 1f ), their power output was significantly higher in the successful trial (trial 2) (t=-10.27, p=0.000, η2=0.73), reflected in a faster performance time. as highlighted previously and in contrast to the unsuccessful participants, pa and na fluctuated considerably less (figs 1d and e). in both trials 1 and 2, successful participants produced a similar end spurt for the last km. discussion an important finding of this exploratory research included the microoscillations in pa and na throughout time trials. the levels of positivity and negativity reported by participants were shown to oscillate – evidence of the dynamic, emotive nature of sport performance. the stream of affect[1] was evident, with pa and na changing differently between successful and unsuccessful trials, and also varying considerably within each time trial. high levels of pa and lower levels of na were associated with better performance by the cyclists, further supporting the key role that affect plays in the generation of an optimal sports performance. it is important to note that this pattern emerged throughout the time trials, not only prior to the activity being performed, as has previously been found prior to climbing performance[5] and wrestling.[7] the analysis of affect, goal expectations and performance between the successful and unsuccessful trials yielded another key finding. goal expectations and affect were closely related throughout the cycle time trial, and in line with previous research,[6] unsuccessful performances were characterised by increased na, decreased pa and reduced goal expectations from the outset of the trial. over the course of a time trial, particularly when athletes are striving for a time goal, they make many assessments regarding their performance and rate of goal progress,[16] and paralleling this assessment is the accompanying affect.[9] during unsuccessful trials, cyclists also reported a continual decrease in their beliefs of goal achievement, accompanied by continued high levels of na, providing further support for the performance-goal discrepancy and resultant affective states. these findings reinforce those of a previous analysis [15] where slow trials (v. fast trials), were characterised by increased na, decreased pa and decreased goal expectations. further more, slow trials were characterised by increased integrated electromyography yet lower power output, but similar ratings of perceived exertion, which the authors suggested were symptomatic of goal striving. the findings in our analysis demonstrate that the psychological changes in affect are exacerbated by continual failure to achieve goals. increased variability of affect, both in magnitude and frequency, occurred in participants who experienced continually increasing discrepancies between desired and actual behaviour. we suggest, therefore, that goal striving was occurring and that ongoing assessment of goal achievement mediates the affectperformance relationship. it is important to note at this point that the cyclists who were unsuccess ful started the trial with a higher power output than in their previous trial. power output subsequently decreased from trial distances of 6.5 15 km. concurrent with this was increased variability in pa (10 15 km) and na (12 17 km), similar to the peak of psychological crises reported by marathon runners three-quarters of the way through a race.[11] it is likely that the decreased power output, perception of goal progress and the affective response experienced by the cyclist were crucial at this point in the time trial. a discrepancy between the cyclists’ goal expectations and actual performances existed, power output decreased, the cyclists became increasingly more negative and less positive than their more successful counterparts, while large oscillations in affect were evident between 10 km and 17 km (figs 1a and b), suggesting frequent cognitive appraisals regarding their situation.[17] this combination of factors suggests ineffective goal striving and possible goal disengagement for the unsuccessful cyclists. undesirable changes in affect and difficulty in goal pursuit can lead to a change in goal-directed behaviour and possible goal disengagement,[18] and where effort is reduced yet the athlete remains committed to their goal, negative feelings of distress result.[16] we were unable to surmise the causal relationships between the psycho logical and physical performance factors from this study. in exer cise settings, increased physical work approaching maximal intensity has been proposed to cause universal negative shifts in affect[4], although the extent to which this holds true for competitive athletes is unclear and it does not fully explain differences between successful and unsuccessful cyclists working maximally in the current study. baden et al.[10] suggested that fatigue may be an emotional construct, after observing increases in na concurrent with increases in ratings of perceived exertion. it is plausible that affect changes reported by the unsuccessful cyclists here were the result of increased fatigue[10] from unsustainable power output, and reflected peripheral physiological status.[15] conversely, the reduced power output may have been the result of increased negativity, with subsequent reduced desire to maintain exercise intensity.[12] where affective loading (defined by baron et al.[12] as the difference between na and pa) surpasses a threshold point (the athlete’s highest tolerated affective loading for an expected exercise duration), the desire to sustain high levels of effort decreases, possibly to maintain physiological and emotional homeostasis. the unsuccessful cyclists in this study had higher levels of affective loading (range 3 to -4) than the successful cyclists (range -5 to -9); hence this explanation is plausible for this finding. it is also possible that inaccurate assessment of performance expectations, which would have implications for the accuracy of goal setting pre trial,[19] might have accounted for the aggressive start which unsuccessful participants could not maintain for the duration of their second time trial. both pre-trial goal expectation and affect were suboptimal for the unsuccessful participants, and this perhaps reflects the lack of confidence in the goal set by these participants and their ability to achieve it. participants were club-level athletes; elite athletes may be better able to assess physiological status prior to time trials and hence be more accurate in the outcome goals that they set. it is clear that, post trial, the unsuccessful cyclists had low levels of pa and feelings of failure, and this has implications for perceived competence.[7] however, goal disengagement can be an important part of the self-regulation process and produce positive feelings.[16] indeed, sajsm vol. 26 no. 1 2014 25 heckhausen et al.[18] stressed that ‘the regulatory challenge ... lies in identifying when goal pursuit is maladaptive while it’s still ongoing and the individual is fully engaged’ (p. 39). hence future research assessing goal expectancy, goal pursuit and goal striving together with affect and physiological parameters is warranted to identify the threshold point at which goal striving remains beneficial or becomes detrimental to the individual in the longer term. study limitations our study was exploratory and we recognise the limitations of the relatively small sample and the variance in participants’ training status implied through the differences in performance times between successful and unsuccessful participants. however, the findings show consistent micro-oscillations in affect throughout the time trial, exacerbated by a lack of success, extending previous research (e.g. gaudreau et al.[9]) and highlighting an interesting area for future research. limited research considers the ongoing psychological change during sport, and the self-regulation framework[8] provides a suitable platform to analyse affect, goal expectation and indeed other variables such as self-efficacy. in this study, affect-goal relationships were inextricably linked with power output and performance. their change has the potential to affect decision-making, and understanding these factors while activity is ongoing is important.[18] as such, we advocate further study of these variables and how they affect each other during performance in larger, controlled studies. conclusion micro-oscillations in pa and na occurred during cycle time trials and were different between successful and unsuccessful trials. affect profiles more conducive to better performance were characterised by higher levels of pa and lower levels of na, and these differences occurred from the outset of the trial. affect and goal expectations were closely related, with goal expectations increasing during successful trials. successful cyclists reported higher levels of goal expectation from the outset of the trial. unsuccessful cyclists, although starting trials with higher levels of power, were unable to sustain these levels, which deteriorated up to 15 km, with corresponding decreases in goal expectations and pa and increases in na. these circumstances may be accounted for by inaccurate goal-setting and assessment of performance expectations prior to the start of the time trial. a full understanding of the catalyst of the time trial performance demise requires further interdisciplinary analysis of both psychological and physiological parameters in parallel. research examining athletes’ experiences of goal striving and goal disengagement would elucidate the factors associated with goal pursuit, which may have implications for the regulation of performance 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http://dx.doi.org/0112-1642/07/0012-1029] http://dx.doi.org/0112-1642/07/0012-1029] http://dx.doi.org/10.1037/a0017668] original research sajsm vol. 24 no. 4 2012 107 various studies have attempted to explore the risk factors associated with injury in rugby.2 however, most of them focus their attention on biographical, physical, environmental and technical factors. the role of psychological factors such as anxiety is largely neglected, except for studies exploring the role of worry and stress in rugby injury.3 the rising occurrence rate of injuries in both professional and club rugby has posed a major challenge which has to be dealt with,4 more specifically at the south african university and club levels.5 many coaches and talent scouts place much focus on the above abilities and promote programmes to develop bigger, physically stronger, faster and more talented players who can excel in their sport.6 nonetheless, these programmes utilised for rugby players at university and club level did not provide adequate emphasis on the prevention and treatment management of previous injuries.6 as a result, injuries at university and club level may continue to increase unless preventive methods that are suited for the game of rugby are implemented.7 because it is a contact sport, rugby poses a high risk for injury.8 lower limbs are most often involved in rugby injuries, with the knee being the most frequent site. shoulder injuries account for the second most loss in time (days) for rugby players.5 during the 2007 rugby world cup shoulder injuries accounted for the loss of 9.4/1 000 playing-hours.9 shoulder injuries in rugby shoulder injuries account for 6 19% of joint injuries in rugby. most of these injuries seem to be dislocations, amounting to 80% of all shoulder injuries among elite australian rugby players10 and accounting for 123 days’ absence for every 1 000 playing hours among elite english rugby players.11 acromioclavicular joint injury and shoulder impingement accounted for 55/1 000 and 54/1 000 days missed, respectively.11 a study by headey et al.12 revealed alarming statistics on shoulder injuries in rugby. damage to the acromioclavicular joint (32%) and rotator cuff injury or shoulder impingement (23%) made up the largest number of shoulder injuries. yet, dislocation or shoulder instability, which made up 14% of shoulder injuries among rugby players, caused 42% of days missed per season due to injury. therefore, dislocations seem to be the most costly shoulder injury to rugby players. front-row forwards and backline players (centres and fullbacks) had the highest number of shoulder injuries. most of the research, however, focuses on understanding the physical reasons for shoulder injuries in rugby, and neglects psychological reasons such as anxiety as a contributing factor to shoulder injuries. this article explores the relationship between shoulder injuries and anxiety. anxiety and shoulder injuries in rugby anxiety has been defined as a negative mood state associated with worry and apprehension.13 theoretically, anxiety in sport is conceptualised from an emotional perspective with both traitand state-like characteristics.13 anxiety has been conceptualised as a multidimensional construct and differentiated as somatic (muscle tension) or cognitive anxiety (worry).14 the relationship between anxiety and sport performance has been studied extensively, mostly showing a curvilinear relationship between anxiety and performance. dunn and sytoruik15 studied the causes of excessive worry in highcontact sport and found that four domains of sport were associated the relationship between anxiety and shoulder injuries among south african university and club rugby players r l van niekerk, e lynch department of psychology, university of johannesburg r l van niekerk, d lit et phil (psychology) department of sports sciences, university of johannesburg e lynch, bsc hons (sport science) corresponding author: l van niekerk (leonvn@uj.ac.za) objectives. this correlational study investigated the relationship between competitive anxiety and shoulder injuries in a sample of club rugby players (n=112) from two universities and three suburban clubs. methods. the participants were asked to complete a biographical questionnaire and the sport competition anxiety test,1 while the injury history of the players for the 2012 season was obtained from the responsible health professions after consent was given. group differences and a direct logistical regression were calculated to determine the relationship between injury and anxiety. results. the results indicated that rugby players who contracted a shoulder injury in a 1-year season have significantly higher levels of anxiety than those players who did not. however, the effect size of the difference seems to be small. the anxiety levels of players with shoulder injuries were regarded as too high when competing. a logistical regression, including various factors, was able to predict injury fairly well, but anxiety seems to be the only variable that contributed significantly to the model. conclusion. the results suggest that the contribution of anxiety to the occurrence of shoulder injuries in club and university rugby cannot be ignored. the high level of anxiety associated with players who suffered shoulder injuries has to be targeted with anxiety management skills as part of a player development and injury management programme. s afr j sm 2012;24(4):107-111. doi:10.7196/sajsm.353 mailto:leonvn@uj.ac.za 108 sajsm vol. 24 no. 4 2012 with anxiety. these include fear of failure, fear of negative social evaluation, fear of injury and fear of the unknown. psychological factors such as stress were found to be a good predictor of injury among new zealand rugby players. two studies investigating stressors among professional rugby union players found that injury was among the top three stressors reported by rugby players.methods the specific objectives of this study were to explore the relationship between anxiety and shoulder injuries among university and club rugby players. forthcoming from this aim, the following research questions were asked: • what is the extent of shoulder injuries among university and club rugby players? • what is the level of anxiety among university and club rugby players? • is there a relationship between anxiety and shoulder injuries among university and club rugby players? the study therefore aimed to explore the constructs of shoulder injury and anxiety and examine the relationship between these constructs. two universities and three inner-city rugby clubs were invited to participate in the study. permission to do the study was granted by the management of all the clubs, except for one university that was not willing to disclose their injury records to the researchers. this was acceptable due to the competitive nature of university rugby. players who gave their consent were asked to complete the questionnaires and their injury records were examined with the permission of the relevant health professionals. sample a sample of 112 first-team rugby players with a mean age of 25.0±3.3 (range: 20 35 years) from two universities (n=45, 40%) and three urban clubs (n=67, 60%) were included in the study. the two universities included 28 (25%) and 17 (15%) and the clubs 27 (24%), 18 (16%) and 22 (20%) of the participants respectively in the sample. players were represented in all 15 positions with a distribution of 54 (48%) backline and 58 (52%) forward players in the sample. instruments biographical questionnaire players were asked to complete a biographical section in the questionnaire. various factors such as age and player position were assessed. sport competition anxiety test (scat) players were asked to complete the scat,1 which consists of 15 questions on a 3-point likert scale (1=‘hardly ever’, 2=‘sometimes’ and 3=‘often’). only 10 of the questions are included in the calculation of the players’ anxiety score. the test measures the players’ anxiety levels in competition contexts.14 norm scores were established by martens1 and found to be comparable to athletes in the south african context20 as follows: a score of 10 16 is regarded as low anxiety, 17 22 as moderate anxiety and a score above 23 as high anxiety. athletes with moderate anxiety usually perform at best. the curvilinear relationship between anxiety and performance, however, implies that players with low or high anxiety will experience a decreased performance.1 various researchers found high reliability and validity on the instrument with an internal consistency (cronbach’s alpha) of between 0.8 and 0.85 in their research 1 a high internal consistency (α=0.934) was found for the scat in this research. injury reports player injuries were evaluated from a 1-year period injury report previously compiled by the respective club physiotherapist or biokineticist. a number of factors were considered, such as injury history, strength and conditioning history, pre-habilitation adherence (pre-injury treatment programme), mechanism of injury and expected return date. results the prevalence of shoulder injuries in the sample is presented in table 1. almost one-third (n=26, 27%) of the players had a shoulder injuring during the year. a large group (n=69, 73%) did not have a shoulder injury. however, they might have had another type of injury not reported within the scope of this study. the anxiety levels of most players were moderate (n=52, 53%). only 19% of the players had low anxiety. a significant group (n=28, 28%) of the sample reported high levels of anxiety when competing. further analysis (table 2) applying an independent sample t-test indicated a statistically significant difference (t (80)=0-3.01, p=0.003, two-tailed) between the anxiety levels of players who had a shoulder injury (m=23.54±5.98) and those who did not (m=19.20±4.51). players with shoulder injuries had significantly higher levels of anxiety, which placed them in a category with too high anxiety when competing. the players with no shoulder injuries reported moderate levels of anxiety. the mean difference (4.34, 95% ci: -7.20 to -1.47) indicated a small effect size (eta squared=0.102). most of the primary shoulder injuries were dislocations (31%), followed by impingement (12%) and rotator cuff strain (12%). other shoulder injuries (table 3) were fewer in comparison. most secondary shoulder injuries, however, were rotator cuff tears (27%), followed by muscle tightness (12%). the results further indicated that in a large proportion of players (81%) a first shoulder injury is followed by a second shoulder injury. the chances of a third shoulder injury, however, are slim, and 89% of the players did not suffer a tertiary injury. table 1. prevalence of shoulder injuries and anxiety among rugby union players condition frequency (n) proportion (%) presence of an injury no injury 69 73 shoulder injury 26 27 anxiety level low 19 19 moderate 52 53 high 28 28 sajsm vol. 24 no. 4 2012 109 the context in which the shoulder injuries were contracted was also investigated and is presented in table 4. most of the players who had a shoulder injury (n=20, 77%) were part of a strength and conditioning programme and indicated that they adhered to it. however, fewer of these players (n=14, 54%) adhered to a pre-habilitation programme. only 8 (31%) players reported that their shoulder injuries were recurring injuries. the two factors implicated most frequently as the mechanism for injury were tackles (n=16, 62%) and overtraining/ incorrect training techniques (n =8, 31%). most of the players (n=8, 31%) returned to play immediately, followed by 15 28 days lost before expected return to play for 6 (23%) players. playing positions that were most at risk to contract a shoulder injury were those of centres and full-backs (n=10, 39%) and the tight five (n=6, 23%).a statistically significant difference was found between the anxiety levels of players who adhered to a strength and conditioning programme (m=19.16±3.95) and those who did not (m=21.67±6.35; t (97)=2.31, p=0.023 two-tailed). this implies that players who adhere to such programmes are less anxious when competing. this was not the same for the adherence to a pre-habilitation programme. the anxiety levels for players who adhered to such a programme (m=18.70±3.51) and players who did not (m=20.30±5.18; t (97)=1.604, p=0.112 two-tailed) were not statistically significant. although players in the centre and full-back positions were more frequently at risk for an injury, there was no significant difference between the anxiety levels of player positions: backline (m=20.10±4.38) and forward players (m=19.45±5.07; t (97)=0.648, p=0.495 two-tailed). no statistically significant differences were found for the other contextual factors associated with shoulder injuries among the participants. a direct logistical regression was performed to determine the influence of various independent variables (age, anxiety, adherence to a strength and conditioning programme, adherence to a prehabilitation programme and playing position) on the prediction of a shoulder injury. although the proposed model was not supported by the omnibus tests of model coefficients (χ2 test must be significant), χ2 (5, n=82)=9.36, p=0.096 (χ2-test must be significant), it was supported by the hosmer-lemeshow goodness of fit test, χ2 (8, n=82)=10.62, p=0.224 (χ2-test should not be significant). this implies that the model was able to differentiate between players who were injured and those who were not. the model was able to explain between 11% (cox and snell r squared) and 19% (nagelkerke r squared) of the variance in injury, and could classify 85% of the cases correctly. only anxiety made a statistically significant contribution to the model (see table table 2. group comparisons for the relationship between anxiety and the presence of injuries among rugby union players group frequency (n) mean ± sd standard error (mean) p-value (sign) presence of an injury no injury 69 19.20 ± 4.51 0.543 0.003 shoulder injury 13 23.54 ± 5.98 1.659 table 3. type of shoulder injuries as a function of primary, secondary and tertiary injuries among rugby union players type of injury primary injury secondary injury tertiary injury frequency (n) proportion (%) frequency (n) proportion (%) frequency (n) proportion (%) dislocation 8 31 1 3.8 0 0 impingement 3 12 2 7.7 0 0 rotator cuff strain 3 12 1 3.8 0 0 subluxation 2 7.7 1 3.8 1 3.8 inflammation 2 7.7 1 3.8 0 0 muscle tightness 2 7.7 3 12 0 0 glenoid labrum tear 1 3.8 1 3.8 0 0 tendon muscle rupture 1 3.8 0 0 0 0 hill-sachs lesion 1 3.8 1 3.8 0 0 tendonitis 1 3.8 2 7.7 0 0 nerve injuries 1 3.8 0 0 1 3.8 bone bruising 1 3.8 1 3.8 0 0 rotator cuff tear 0 0 7 27 1 3.8 acromioclavicular joint sprain 0 0 2 7.7 0 0 none 0 0 5 20 23 89 total 26 100 26 100 26 100 110 sajsm vol. 24 no. 4 2012 5). although it was not the strongest predictor of injury in the model, an odds ratio of 1.196 was recorded for anxiety. the implication is that players who were anxious during competition were 1.2 times more likely to get a shoulder injury. discussion the results capsulated the costly effect of shoulder injuries among university and club rugby players. despite the effort and pressure to deal with injuries4,5 and the promotion of prevention and injury management programmes,6 almost a third of the rugby players had a shoulder injury during a 1-year season, which is higher than found in other studies.10 the extent of the injuries kept the players out of the game for between 1 and 2 months, reflecting the playing time lost due to injury, which was equally alarming as that among elite rugby players.11 regarding the type of injury, dislocations, impingements and rotator cuff strains made up most of the shoulder injuries. various other studies found these types of injuries among the highest shoulder injuries contracted by rugby players.10-12 more than two-thirds of the table 4. contextual factors associated with shoulder injuries in rugby union players factor condition frequency (n) proportion (%) adherence to a strength and conditioning programme yes 20 77 no 6 23 adherence to a pre-habilitation programme yes 14 54 no 12 46 recurring injury yes 8 31 no 18 69 mechanism of injury tackle 16 62 overtraining and incorrect training technique 8 31 weight training 2 7.7 expected days to return 0 days, currently training 8 31 1 7 days 4 15 8 14 days 1 3.8 15 28 days 6 23 29 42 days 2 7.7 43 56 days 4 15 57 112 days 1 3.8 playing positions centres and full-back 10 39 tight five 6 23 utility forwards 4 15 loose forwards 3 12 utility backs 2 7.7 halves and wings 1 3.8 table 5. logistic regression predicting likelihood of a shoulder injury 95% ci for exp(b) b se wald df sig exp(b) lower upper age -0.003 0.079 0.001 1 0.971 0.997 0.854 1.165 anxiety 0.179 0.073 6.016 1 0.014 1.196 1.037 1.380 strength and conditioning 0.401 0.764 0.275 1 0.600 1.493 0.334 6.669 pre-habilitation programme -0.238 0.969 0.060 1 0.806 0.788 0.118 5.269 playing position 0.459 0.661 0.482 1 0.487 1.582 0.434 5.774 constant -5.579 2.403 5.389 1 0.020 0.004 sajsm vol. 24 no. 4 2012 111 shoulder injuries were due to the mechanisms of tackling. these results emphasise the high risk2 that the nature of the sport11,12 presents. in this regard, the player positions at a higher risk to contract a shoulder injury were the centers, full-backs and tight five. although most of the players adhered to a strength and conditioning programme, almost half did not adhere to a pre-habilitation programme. this might be due to the focus of scouts and coaches on developing bigger, physically stronger and faster players6 at the expense of preventing injuries. an alarming result in this regard was the high number of players who had a second shoulder injury: 4 in every 5 players who contracted a shoulder injury also contracted a second shoulder injury, while a third of the shoulder injuries were reported to be a recurring injury. the role of anxiety in shoulder injuries cannot be ignored, as there was a significant difference between the anxiety levels of players with and without shoulder injuries. those who contracted shoulder injuries had much higher anxiety than those who did not. their anxiety put them in a category too high2,14 for effective performance. further, anxiety was the only factor in a logistical regression that significantly contributed (11 19% of the variance) to the prediction of a shoulder injury among university and club rugby players. as anxiety is associated with muscle tension and narrowing of attention,17 its role in the tightening of shoulders during tackling and unsuspected tackling (due to too narrow attention) should not be underestimated. these results suggest that the inclusion of anxiety management techniques during training and competition should be considered. anxiety and apprehension,13 general fears and fear of re-injury,15 stress18 and concern3,19 among rugby players are all related to injuries.16 references 1. martens r. sport competition anxiety test. champaign: human kinetics, 1982. 2. chalmers dj, samanarayaka a, gulliver p, mcnoe b. risk factors for injury in rugby union football in new zeeland: a cohort study. br j sports med 2012;46(2):95-102. [http://dx.doi.org/10.1136/bjsports-2011-090272] 3. nicholls ar, jones cr, polman rcj, borkoles e. acute sport-related stressors, coping and emotion among professional rugby union players during training and matches. scand j med sci sports 2009;19(1):113-120. 4. garraway wm, lee aj, hutton sj, russell eb, macleod da. impact of professionalism on injuries in rugby union. br j sports med 2000;34(5):348-351. [http://dx.doi. org/10.1136/bjsm.34.5.348] 5. gray j. preventative rehabilitation for rugby injuries to the shoulder. cape town:sa rugby, 2009. http://www.sarugby.co.za/boksmart/pdf (accessed 18 september 2012). 6. quarrie kl, handcock p, toomey mj, walter ae. the new zeeland rugby injury and performance project iv: anthropometric and physical performance comparisons between positional categories of senior a rugby players. br j sports med 1996;30(1): 53-55. 7. erasmus h, spamer ej. effect of a prevention programme on the incidence of rugby injuries among 15 and 16 year-old schoolboys. s afr j sports med 2007;19(2):46-57. 8. fuller c, drawer s. the application of risk management in sports. j sports med 2004;34(6):349-356. 9. fuller cw, laborde f, leather rj, molloy mg. international rugby board rugby world cup 2007 injury surveillance study. br j sports med 2008;42:452-459. 10. bathgate a, best jp, craig g, jamieson m. a prospective study of injuries to elite australian rugby union players. br j sports med 2002;36:265-269. [http://dx.doi. org/10.1136/bjsm.36.4.265] 11. brooks hjm, fuller cw, kemp spt, reddin db. a prospective study of injuries and training amongst the england 2003 rugby world cup squad. br j sports med 2005;39:288-293. [http://dx.doi.org/10.1136/bjsm.2004.013391] 12. headey j, brooks jhm, kemp spt. the epidemiology of shoulder injuries in english professional rugby union. am j sports med 2007;35(9):1537-1543. 13. weinberg rs, gould d. foundations of sport and exercise psychology. champaign: human kinetics, 2011. 14. martens r, vealy rs, burton d. competitive anxiety in sport. champaigne: human kinetics, 1990. 15. dunn jgh, sytoruik dg. an investigation of multidimensional worry dispositions in a high contact sport. psychology of sport and exercise 2003;4:265-282. [http://dx.doi. org/10.1016/s1469-0292(02)00005-5] 16. cassidy cm. understanding sport-injur y anxiety. athletic therapy today 2006;11(4):57-58. 17. andersen mb, williams jm. a model of stress and athletic injury: prediction and prevention. journal of sport and exercise psychology 1988;10(3):294-306. 18. maddison r, prapavessis h. the psychological approach to the prediction and prevention of athletic injury. journal of sport and exercise psychology 2005;27(3):289310. 19. nicholls ar, backhouse sh, polman rcj, mckenna j. stressors and affective states among professional rugby union players. scand j med sci sports 2009;19:121-128. 20. potgieter j. norms for the sport competition anxiety test (scat). south african journal for research in sport, physical education, and recreation 2009;31(1):69-79. http://dx.doi.org/10.1136/bjsports-2011-090272] http://dx.doi.org/10.1136/bjsm.34.5.348] http://dx.doi.org/10.1136/bjsm.34.5.348] http://www.sarugby.co.za/boksmart/pdf http://dx.doi.org/10.1136/bjsm.36.4.265] http://dx.doi.org/10.1136/bjsm.36.4.265] http://dx.doi.org/10.1136/bjsm.2004.013391] http://dx.doi.org/10.1016/s1469-0292 http://dx.doi.org/10.1016/s1469-0292 62 sajsm vol. 26 no. 2 2014 case study this case report describes chronic exertional compartment syndrome in the forearm of a professional rower. we consider this to be a rare anatomical location for this type of syndrome. morever, not much is known about its clinical presentation and the subsequent optimal medical management thereof. s afr j sm 2014;26(2):62-63. doi:10.7196/sajsm.547 chronic exertional compartment syndrome in the forearm of a rower p volcke,1,2 md, mmed (sports med); j h kirby,1 mb chb, msc (sports med); p l viviers,1 mb chb, mmed sc, msc (sports med); j t viljoen,1 bsc (physio), mphil (exercise sci) 1 campus health service and the centre for human performance sciences, stellenbosch university, south africa 2 department of physical medicine and rehabilitation, catholic university of leuven, belgium corresponding author: p viviers (plv@sun.ac.za) chronic exertional compartment syndrome (cecs) in the lower limb is a well-known clinical condition that has been extensively described to date. conversely, the forearm is affected much less frequently, with only a few cases having been reported in sports such as weightlifting, kayaking and motocross.[1,2] we present a case of cecs in the forearm of a professional rower. case report a 32-year-old professional male rower complained of pain in the forearm when paddling. the pain had been present for 4 months and was associated with a loss of power and paresthesia of the fourth and fifth fingers. clinically, symptoms were reproduced when squeezing a tennis ball. most significantly, there was no pain at rest, only during and after exertion, with the pain and associated paresthesia disappearing 10 minutes after cessation of activity. examination of the cervical spine, shoulder and elbow, as well as radial and ulnar arterial flow, was normal. a stryker device was used to perform an intracompartmental pressure (icp) measurement (fig. 1). testing of the flexor compartments revealed a raised resting pressure of 16 mmhg, a raised 1-minute postexercise pressure of 70 mmhg and a raised 5-minute postexercise pressure of 24 mmhg. based on the history and the raised intracompartmental pressure, the diagnosis of cecs in the flexor compartment of the forearm was made and a fasciotomy was performed (fig. 2). following surgery, immediate range-of-motion exercises of the hand and wrist were permitted. after 6 weeks, a gradual return to paddling was initiated. a full return to sport was accomplished within 3 months. discussion cecs in the forearm is an uncommon diagnosis for intermittent forearm pain. the combination of a suggestive history and positive icp measurement still remains the golden standard in diagnosing cecs. determination of exact values to confirm the diagnosis of cecs is a subject of discussion. pedowitz et al.[3] have reported the following values suggestive of cecs in the lower limb: a preexercise pressure of ≥15 mmhg, a 1-minute postexercise pressure of ≥30 mmhg, or a 5-minute postexercise pressure of ≥20 mmhg. determination of cut-off values before and after exertion for the upper limb is difficult because cecs in the forearm is scarce. ardolino et al.[4] described a normal reference range of flexor and extensor fig. 2. postsurgical decompression. fig. 1. method of compartment pressure measurement. mailto:plv@sun.ac.za sajsm vol. 26 no. 2 2014 63 forearm compartment pressures: for the extensor compartment of the forearm, the upper value is 25.2 mmhg and for the flexor compartment, it is 21.4 mmhg. recent studies suggest magnetic resonance imaging (mri) as an alternative to compartment pressure measurement to diagnose cecs because it is non-invasive and easily tolerated.[5,6] in addition, postexertional mri can show signal intensity changes in patients with cecs. however, a confounding factor with mri is that eccentric training in untrained individuals may lead to increased signal intensity in the muscular compartments, which mimics cecs findings.[5] van den brand et al.[7] showed comparable sensitivity but lower specificity of mri to that of icp, and concluded that mri is less suitable in diagnosing cecs. to date, conservative treatment of cecs has been highly unsuccessful; consequently, guidelines in the literature regarding conservative protocols are lacking.[8,9] management usually implies surgical decompression of the muscle compartments. winkes et al.[10] suggested that partial fasciectomy or fasciotomy are equally successful procedures. postsurgical rehabilitation is not well documented; it focuses on optimisation of the outcome and reduction of the risk of reccurence. there are some proposed guidelines, but further research to establish a general rehabilitation programme is necessary.[11] interestingly, a recent case study by isner-horobeti et al.[12] describes the use of botulinum toxin in the treatment of lower leg cecs. botulinum toxin decreases muscle mass and therefore causes a reduction of the intramuscular pressure. unfortunately, this treatment has only a temporary effect and decreases the strength of the muscle.[12] conclusion cecs in the forearm is a rare but important pathology to consider in the differential diagnosis of forearm pain. diagnosis is based on a suggestive history in combination with a positive icp measurement. the treatment of choice is surgical decompression. acknowledgements. we would like to thank dr edwin dillon (orthopaedic surgeon, mediclinic stellenbosch, south africa) for his clinical participation and use of the images provided. references 1. brown js, wheeler pc, boyd kt, barnes ml, allan mj. chronic exertional compartment syndrome of the forearm: a case series of 12 patients treated with fasciotomy. j hand surg eur vol 2011;36(5):413-419. [http://dx.doi. org/10.1177/1753193410397900] 2. piasecki dp, meyer d, bach br jr. exertional compartment syndrome of the forearm in an elite flatwater sprint kayaker. am j sports med 2008;36(11):2222-2225. [http:// dx.doi.org/10.1177/0363546508324693] 3. pedowitz ra, hargens ar, mubarak sj, gershuni dh. modified criteria for the objective diagnosis of chronic compartment syndrome of the leg. am j sports med 1990;18:35-40. 4. ardolino a, zeineh n, o’connor d. experimental study of forearm compartmental pressures. j hand surg am 2010;35(10):1620-1625. [http://dx.doi.org/10.1016/j. jhsa.2010.06.017] 5. gielen jl, peersman b, peersman g, et al. chronic exertional compartment syndrome of the forearm in motocross racers: findings on mri. skeletal radiol 2009;38(12):1153-1161. [http://dx.doi.org/10.1007/s00256-009-0746-2] 6. raphael bs, paletta ga, shin ss. chronic exertional compartment syndrome of the forearm in a major league baseball pitcher. am j sports med 2011;39(10):2242-2244. [http://dx.doi.org/10.1177/0363546511417171] 7. van den brand jg, nelson t, verleisdonk ej, van der werken c. the diagnostic value of intracompartmental pressure measurement, magnetic resonance imaging, and near-infrared spectroscopy in chronic exertional compartment syndrome: a prospective study in 50 patients. am j sports med 2005;33(5):699-704. [http://dx.doi. org/10.1177/0363546504270565] 8. brennan fh jr, kane sf. diagnosis, treatment options, and rehabilitation of chronic lower leg exertional compartment syndrome. curr sports med rep 2003;2(5):247250. [http://dx.doi.org/10.1007/s11932-003-0055-9] 9. shah sn, miller bs, kuhn je. chronic exertional compartment syndrome. am j orthop 2004;33(7):335-341. 10. winkes mb, luiten e, van zoest w, sala ha, hoogeveen ar, scheltinga mr. longterm results of surgical decompression of chronic exertional compartment syndrome of the forearm in motocross racers. am j sports med 2012;40(2):452-458. [http:// dx.doi.org/10.1177/0363546511425647] 11. schubert ag. exertional compartment syndrome: review of the literature and proposed rehabilitation guidelines following surgical release. int j sports phys ther 2011;6(2):126-141. 12. isner-horobeti me, dufour sp, blaes c, lecocq j. intramuscular pressure before and after botulinum toxin in chronic exertional compartment syndrome of the leg. am j sport med 2013;41(11):2558-2566. [http://dx.doi.org/10.1177/0363546513499183] http://dx.doi.org/10.1177/1753193410397900] http://dx.doi.org/10.1177/1753193410397900] http://dx.doi.org/10.1177/0363546508324693] http://dx.doi.org/10.1177/0363546508324693] http://dx.doi.org/10.1016/j.jhsa.2010.06.017] http://dx.doi.org/10.1016/j.jhsa.2010.06.017] http://dx.doi.org/10.1007/s00256-009-0746-2] http://dx.doi.org/10.1177/0363546511417171] http://dx.doi.org/10.1177/0363546504270565] http://dx.doi.org/10.1177/0363546504270565] http://dx.doi.org/10.1007/s11932-003-0055-9] http://dx.doi.org/10.1177/0363546511425647] http://dx.doi.org/10.1177/0363546511425647] http://dx.doi.org/10.1177/0363546513499183] original research sajsm vol. 25 no. 1 2013 23 background. ankle injuries are one of the most common injuries in sport and have a high recurrence rate. aim. to determine the prevalence of clinical signs of ankle injuries in club rugby players in south gauteng. methods. institutional ethical clearance was obtained for the study. of the 180 players from 9 clubs who were eligible for participation in the study, 76% (n=137) were recuited. informed consent was obtained before players were asked to complete a battery of tests. each player was asked to complete a demographic questionnaire and the olerud and molander questionnaire to determine the prevalence of clinical signs of perceived instability. the prevalence of clinical signs of mechanical instability was determined by the anterior drawer test (adt) and talar tilt test (ttt). balance and proprioception were assessed by the balance error scoring system (bess) and this was used to determine the prevalence of clinical signs of functional instability. results. the prevalence of perceived instability was 44%. the prevalence of clinical signs of mechanical ankle instability was 33%. there was an increased prevalence of mechanical instability in players who had a history of previous ankle injuries: adt left (p=0.003); adt right (p=0.01); ttt left (p=0.001); ttt right (p=0.08), both tests positive left (p=0.001) and both tests positive right (p=0.03). the prevalence of clinical signs of functional ankle instability depended on the surface and visual input, and was greater as the challenge or perturbation increased. conclusion. there was a high prevalence of clinical signs of ankle instability in club rugby players for perceived, mechanical and functional instability. those with previously injured ankles were more likely to have unstable ankles. s afr j sm 2013;25(1):23-27. doi:10.7196/sajsm.347 the prevalence of clinical signs of ankle instability in club rugby players e mellet, a stewart physiotherapy department, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa e mellet, msc (physiotherapy) a stewart, phd corresponding author: a stewart (aimee.stewart@wits.ac.za) rugby requires explosive power for jumping, quick changes of direction and changes in pace when running. in addition, players tackle and are tackled in close-contact situations. ankle injuries are common when the players are involved in these types of activities.[1] the lateral ankle ligament complex is the most vulnerable to injury, with 85 95% of all injuries to the ankle occurring here.[2] prospective epidemiological studies suggest that ankle injuries account for 8 20% of all injuries in rugby:[3] 10% of the injuries recorded for new zealand players in the super 12;[4] 11% in international australian players;[5] 14% in international players at the 2003 world cup; and 20% in scottish district players.[6] in south africa a study revealed 55.4 injuries per 1 000 player game hours and 4.3 injuries per 1 000 player training hours in the super 12 competition, with 7 (11.3%) ankle injuries sustained in total.[7] the study underlined that it was the first of its kind in south africa and that there is a need to collect epidemiological data on rugby injuries to develop appropriate management and prevention programmes. there are 3 different levels of ankle instability, namely perceived, mechanical and functional, which form a continuum.[8,9] perceived ankle instability is the subjective self-evaluation of the player with regard to ankle function. mechanical instability is the increase in accessory movement (arthrokinematic motion that cannot voluntarily be produced, e.g. the glide and roll of the talus in the mortise), which translates into an enlarged neutral zone. mechanical instability is usually the result of a tear or lengthening of one of the ligamentous structures supporting the joint. residual mechanical instability leads to functional ankle instability.[4] the patient with functional instability has deficits of ankle control in postural control tasks. this is explained in part by the fact that the somatosensory receptors are disrupted and this generates a decreased motor response to maintain postural equilibrium. the healing time for ligaments is between 6 weeks and 3 months; however, in a systematic review on ankle injuries it has been shown that, at testing, there are still signs of mechanical laxity and functional instability between 6 months and 1 year after the initial injury.[2] tendon pathology is described as a continuum which requires treatment at appropriate times along the continuum. initially, reactive tendinopathy occurs as a result of an acute overload or a blow. this may progress to tendon disrepair or failed healing if the tendon becomes chronically overloaded.[10] finally, degenerative tendinopathy may occur with progression of cell and matric changes and cell death; again, due to overload.[2,10] there is a 27% recurrence of ankle injuries in rugby[3] and a reported 21% of days absent due to injury could be related to recurrent ankle injuries.[3] it is evident that previous injury predisposes players to future injury, attributed to continued joint dysfunction, pre-existing anatomical and biomechanical factors, or inadequate rehabilitation. [4,9] mailto:aimee.stewart@wits.ac.za 24 sajsm vol. 25 no. 1 2013 residual complaints of the player/athlete include a feeling of weakness or the ankle wanting to ‘give way’, tenderness on palpation, pain or discomfort with running or jumping activities.[10,11] most of the literature focuses on elite professional sportsmen and little is known about the game and its injuries at an amateur level. the aim of this study was therefore to determine the prevalence of positive clinical signs for perceived, mechanical and functional ankle instability in club rugby players in south gauteng, and to compare players with v. those without a previous ankle injury. method we performed a cross-sectional study among all players from the first team squads of the rugby clubs in the south gauteng region of the gauteng lions rugby union first division. nine of the 10 clubs in the region agreed to participate in the study. each squad included 20 players (15 players in the team and 5 reserves). of the 180 players eligible for inclusion, 137 (76%) participated. the remaining 43 players met one or more of the following exclusion criteria: • previous surgery to the lateral ankle ligament complex or ankle joint • previous injury of the lower extremity (within 3 months of the tests) • recently diagnosed concussion (within 1 month of the tests) • current ear infection, head cold or upper respiratory tract infection. ethical clearance was obtained from the human research ethics committee of the university of the witwatersrand. permission was given by the relevant authorities to perform the study and players signed informed consent forms prior to participation in the study. tests perceived ankle instability was established by the olerud and molander questionnaire,[12] which is an investigative tool to make studies of ankle injury more comparable. the olerud and molander questionnaire firstly investigates the patient’s clinical signs and symptoms, including pain, stiffness and swelling. the second part of the questionnaire surveys the functional impact of the injury on the participant’s ability to function in activities of daily life and sport and whether the participant requires external support in the form of taping or bracing to function. mechanical integrity was determined by: (i) anterior drawer test (adt);[1,3] and (ii) talar tilt test (ttt)/stress inversion test.[1,3] the adt (transverse plane laxity) assesses the integrity of the anterior talofibular ligament, while the ttt is an effective indicator of injury to the calcaneofibular ligament. positioning is important to isolate the ankle for testing in the adt. the ankle should be positioned in 10° of plantar flexion and the knee at 90°, because the most anterior laxity of the ankle will be achieved in this position to better isolate the capsular and ligamentous structures of the ankle. a positive adt has a sensitivity of 73% and a specificity of 97%.[13] when accompanied by a skin dimple during testing, there is a high correlation of approximately 94%, with rupture of the lateral ligament complex. a positive adt with pain on palpation and signs of haemorrhage has a sensitivity of 100% and specificity of 77%.[13] to determine laxity, the test must be done on the affected and unaffected side and then a comparison must be made. the ttt determines the amount of inversion of the calcaneus when the tibia is stabilised. this, again, is a comparative test for side-to-side differences. this test is only an adjunct to the adt and is reported to be less reliable in predicting injury. functional instability was determined by the balance error scoring system (bess).[14] the use of bess has been suggested in a study comparing different techniques for assessing balance. however, it must be clear that no one standing balance test, whether functional or static, can be used to isolate the ankle joint.[15] the ankle is part of the whole kinetic chain and a deficit at any point in the chain will affect balance and ultimately postural control; this needs to be considered even though players were excluded from this study if they had lower extremity pathology. bess is reliable and valid in controlled laboratory environments.[15] the test is performed in 3 progressive stance positions with the difficulty rating increased: namely double-leg, single-leg and tandem stance. these are repeated on two different surfaces: firm and foam. the number of errors made by the subject in a period of 20 seconds is counted. if a subject makes any errors the test is positive. errors include opening the eyes, lifting any part of the foot and stepping out of the stance position.[14] for the adt in this study the subject was asked to lie supine and the knee was semi-flexed to 40°. this position was achieved with the use of a goniometer to eliminate the stabilising effect of a tight gastrocnemius muscle on the excursion of the joint. the first author was positioned in front of the subject. the one hand stabilised the lower leg while cupping the calcaneus with the other hand. the forearm of the hand cupping the calcaneus supported the foot in 10° of plantar flexion. the foot position was checked with a goniometer. the subject was instructed to relax and to allow the researcher (em) to move the ankle. the action performed was an anterior displacement or forward pull of the talus and calcaneus while the other hand stabilised the tibia with a constant force.[16] the adt was deemed positive if the talus glided or slid anteriorly from under the ankle mortise. in certain cases where an audible ‘clunk’ was heard, the suspected instability was supported by the indication of talar subluxation which indicates greater excursion of the talus and thus instability. for the ttt, the patient was positioned supine with the first author sitting facing the patient. the test was performed by holding the calcaneus with one hand while the foot was positioned in the neutral position. the other hand was used to stabilise the lower leg, again around the distal tibiofibular region. the calcaneofibular ligament was palpated with one finger to feel the gapping, if present. the hand stabilising the calcaneus applied an inversion stress by rolling the calcaneus inwards to cause talar tilt. the ttt was deemed positive in the presence of excessive tilting or gapping, or if the patient experienced pain while performing the test. a test is deemed positive if tilting or gapping >3 5 mm is recorded.[16] the first author performed the adt and ttt on all players and was blinded as to their previous injuries. for the bess, 2 testing conditions on 2 different surfaces were used: single-leg stance for left and right leg, on a firm surface (stable flat surface) and a foam surface (a foam block). initially the subject had to maintain balance with his eyes open. the player was then asked to repeat the test with his eyes closed, to remove the focus gained from visual input to control balance. sajsm vol. 25 no. 1 2013 25 single-leg stance was performed by standing for 20 seconds on one leg with the contra-lateral leg held in 30° of hip flexion and 90° of knee flexion (ranges were measured by a goniometer) and the foot held approximately 15 cm off the ground. the subject was asked to close his eyes and place his hands on his iliac crests, while maintaining the appropriate stance. if the subject fell out of position, he had to return to the position as quickly as possible; when the eyes were closed, the player could open his eyes and keep them open until balance was regained before closing them again. the first author, standing 3 m away, recorded the number of errors made by each subject during the test. a test was deemed positive if the player made an error; subjects were graded according to the number of errors made during the 20-second period. these tests were performed after the adt and ttt. prior to performing the test, the subject was instructed, shown and given an opportunity to practise the stance position. data analysis the data were imported into stata release 10 statistical software for analysis. the prevalence of perceived, mechanical and functional instability was presented as a percentage of the whole sample (statcorp). a chi-square test was used to compare the difference in clinical signs of mechanical and functional ankle instability between the group who had never had an ankle injury and the group who reported a previous ankle injury. all testing was done at a p<0.05 level of significance. results table 1 summarises the demographic data of the participants. age, height and weight distribution in the sample varied from adolescent to early 40s, 60 to 130 kg and 156 to 204 cm, respectively. occupations were divided into sedentary (corporate or office-bound) and physical (requiring physical labour as part of their duties). more than 50% of the sample reported a previous ankle injury. forty-four per cent of the players perceived that they had ankle instability (table 2). pain (28%), stiffness (29%) and swelling (15%) were the most prevalent clinical signs, and 17% of players reported that they required some kind of external support (table 3). of the 137 players, 33% had positive tests for clinical signs of mechanical ankle instability irrespective of the side of injury or ligament injured. when side-to-side differences were considered, the left side had a higher percentage of clinical signs compared with the right (tables 4 and 5). the more difficult the testing conditions, the higher the prevalence of decreased postural control and functional instability. the highest percentages of functional instability were found with the test performed on an unstable surface with the eyes closed, for the right leg (98%) and the left leg (96%), respectively (table 6). there were no differences on bess when comparing those with a previous injury with those without, except for the test for the left leg on a firm surface with the eyes closed. again, these results suggest that bess does not isolate the ankle joint, and the results cannot be related to the ankle joint specifically (table 7). thirteen per cent of players reported that they had never fully recovered (table 8). forty-two per cent returned to training and participation in matches after being side-lined for a few weeks; less table 1. demographic data of participants (n=137) age (years), mean (±sd) 24.0 (±4.7) height (cm), mean (±sd) 181.5 (±7.0) weight (kg), mean (±sd) 93.6 (±14.0) occupation, n (%) sedentary physical 71 (52) 66 (48) player position, n (%) forward backline 73 (53) 64 (47) previous injury, n (%) yes no 79 (58) 58 (42) table 2. the prevalence of perceived ankle instability: olerud and molander questionnaire (n=137) narration score* % n (%) no perceived instability 100 77 (56) perceived instability <95 60 (44) *olerud and molander score. table 3. specific perceived functional limitations (n=137) perceived functional limitation n (%) pain 38 (28) stiffness 40 (29) swelling 20 (15) impact on climbing stairs 16 (12) impact on running 6 (4) impact on jumping 8 (6) impact on squatting 9 (7) impact on activities of daily life 11 (8) use of ankle supports 23 (17) table 4. prevalence of clinical signs of mechanical ankle instability (n=137) side and positive test prevalence n (%) left adt ttt adt and ttt 31 (23) 28 (20) 25 (18) right adt ttt adt and ttt 23 (17) 23 (17) 20 (15) left and right any positive clinical signs 45 (33) 26 sajsm vol. 25 no. 1 2013 than the 6-week period that should be observed for soft tissue healing. twenty per cent returned within days after the injury. discussion forty-four per cent of players reported perceived signs of instability. importantly this was a subjective evaluation by the player of the perceived status of the ankle; it is not inferred that these injuries were sustained as a result of playing rugby. the first section of the olerud and molander questionnaire describes the physical signs, including pain (28%), stiffness (29%), and swelling (15%).[12] it is interesting that, despite reports of physical signs of ankle injury, these players were still actively participating in practice sessions and games. this raises the question of whether they may be predisposed to future injury due to inadequate healing time management and rehabilitation. [1] the literature reports an initial healing time of 4 6 weeks for orientation, aggregation and arrangement of soft tissue. in this phase, normal function is possible, but the athlete is still vulnerable to re-injury. over the period of 6 months 2 years, final tissue changes still take place.[10] the functional limitations reported by the players included 4 problems: running (4%), jumping (6%), climbing stairs (12%), and squatting (7%). most of these activities are similar to movements in playing rugby. this may suggest that they should not be participating in games and practice, even though this information was only reported by the participants and not actively tested. where the translation of a joint is not controlled, there will be long-term negative consequences on tissue structure and degeneration of the ankle and subtalar joint, with the possible onset of early osteoarthritis. if the continuum from acute ankle sprain with mechanical deficit to functional instability and then chronic instability occurs, the ankle with perceived instability may eventually end up categorised as chronic instability, this being a sure precursor for early degenerative or arthritic changes. table 5. differences in clinical signs of mechanical ankle instability: those with (n=79) v. those without (n=58) previous ankle injuries positive mechanical test previous ankle injury p-value yes n (%) no n (%) adt, left 25 (32) 6 (10) 0.003* adt, right 19 (24) 4 (7) 0.010* ttt, left 24 (30) 4 (7) 0.001* ttt, right 17 (22) 6 (10) 0.080 both tests positive, left 28 (35) 6 (10) 0.001* both tests positive, right 20 (25) 6 (10) 0.030* both tests positive, left and right 48 (61) 5 (17) 0.001* *p<0.05; more participants who had previous injuries had positive adts and ttts than those without previous injuries: 24 60% v. 7 17%, respectively. table 6. bess: prevalence of positive clinical signs of balance deficits (functional instability)* (n=137) side and stance surface positive signs of balance deficits (functional instability) n (%) left firm, eyes open firm, eyes closed foam, eyes open foam, eyes closed 13 (10) 88 (64) 65 (48) 132 (96) right firm, eyes open firm, eyes closed foam, eyes open foam, eyes closed 13 (10) 76 (56) 66 (48) 134 (98) *there were no differences on bess comparing those with previous injury with those without, except for the test for the left leg on a firm surface with the eyes closed. again, these results suggest that bess does not isolate the ankle joint and the results cannot be related to the ankle joint specifically (table 7). table 7. prevalence of the clinical signs of functional ankle instability: those with (n=79) v. those without (n=58) previous injury side and functional test previous ankle injury p-value yes n/n (%) no n/n (%) left firm, eyes open firm, eyes closed foam, eyes open foam, eyes closed 10/13 (77) 56/88 (64) 36/65 (55) 76/132 (58) 3/13 (23) 32/88 (36) 29/65 (45) 56/132 (42) 0.16 0.04* 0.54 0.17 right firm, eyes open 9/13 (69) 4/13 (3) 0.32 *p<0.05. table 8. time side-lined from games and recovery time (n=79)* n (%) time side-lined not side-lined days weeks months 16 (20) 16 (20) 33 (42) 14 (18) time taken to recover days weeks months never fully recovered 40 (51) 25 (32) 4 (5) 10 (13) time spent on the field full game only one half bench only 72 (91) 5 (6) 2 (3) *thirteen per cent of players reported that they had never recovered. forty-two per cent of players returned to training and participation in matches after being side-lined for a few weeks. this is less than the 6 weeks that should be observed for soft tissue healing. twenty per cent returned within days after the injury. sajsm vol. 25 no. 1 2013 27 rehabilitation is key to effective and successful return to sport. acute management should include anti-inflammatory modalities and exercises to maintain range of motion. once initial healing has occurred, strength and proprioception have to be addressed, and then a graduated return to sport must be supervised.[2,3,10] the prevalence of mechanical instability in the subjects in this study was slightly higher (33%) than that reported in the literature for ankle injuries in sport in general (10 30%), and higher than the reported prevalence for ankle injuries in rugby players (9 15%).[3-6] at a national or provincial level, injuries are usually managed by multi-disciplinary teams, which may decrease the prevalence of injury with correct rehabilitation or identification of risk factors and pre-injury intervention. club rugby players are rarely managed at the club and usually pay for their own treatment. there were far more players with positive adts and ttts among those who reported previous injury than those who had never experienced ankle injuries. this shows that there may be residual mechanical laxity after return to participation in sport, or that the players with some sort of mechanical deficit are more likely to sustain injuries. this asks the question of whether these players return too soon or whether they are not fully rehabilitated when they return to the game. on a stable surface with decreased visual input, 64% of the players standing on the left leg and 56% of the players standing on the right leg were deemed functionally unstable. as soon as a player closed his eyes, even when standing on a stable surface, there were signs of instability. this probably points to the importance of visual input to the central nervous system to control the body in space. pertubation is applied through the constant change in the foot position on the unstable surface.[14] the test does not include the ability to read the surface or adapt to it during the stance phase and simultaneously allow the other foot to clear the ground and propel the body forward during dynamic movement. it has been shown that players with reported functional instability do take longer to stabilise after contacting the ground in a land from a single-leg jump, which assesses functional control. the more challenging the balance perturbation with progression of the test, the greater the positive signs of instability, as shown by the test for the combination of decreased visual input on an unstable surface where 96% of players on the left and 98% on the right showed functional signs of instability. for bess, the whole kinetic chain must be considered and a deficit anywhere in the chain can affect the results.[13,14] conclusion the results of this study demonstrate that ankle injuries in club rugby players are of concern. performance may be severely hampered by incomplete healing and insufficient rehabilitation following injury, with specific manifestations of ankle instability. these results demonstrate the need for further research into methods of adequately assessing and dealing with injuries, to ensure a constant flow of talent from the clubs into the upper echelons of national rugby, namely the provincial and national teams. in addition, standardised comprehensive management plans and the compilation of a preseason screening tool should be considered, to detect biomechanical abnormalities that could improve post-injury results and lead to a graduated return to sport for these athletes. references 1. zöch c, fialka-moser v, quittan m. rehabilitation of ligamentous ankle injuries: a review of recent studies. br j sports med 2003;37:291-295. [http://dx.doi. org/10.1136/bjsm.37.4.291] 2. geiringer sr. management of the athletic ankle sprain: from acute injury to rehabilitation. biomech 1997;4:1-5. 3. sankey ra, brooks jh, kemp sp, haddad fs. the epidemiology of ankle injuries in professional rugby union players. am j sports med 2008;36(12):2414-2424. [http:// dx.doi.org/10.1177/0363546508322889] 4. targett sg. injuries in professional rugby union. clin j sports med 1998;8(4):280285. 5. bathgate a, best jp, craig g, jamieson b. a prospective study of injuries to elite australian rugby union players. br j sports med 2002;36:265-269. [http://dx.doi. org/10.1136/bjsm.36.4.265] 6. garraway wm, lee aj, hutton sj, russell eb, macloed aw. impact of professionalism on injuires in rugby union players. br j sports med 2000;34:348-351. [http://dx.doi. org/10.1136/bjsm.34.5.348] 7. holtzhausen lj, schwellnus mp, jakoet i, pretorius al. the incidence and nature of injuries in south african rugby players in the rugby super 12 competition. s afr med j 2006;96(12):1260-1265. 8. denegar cr, miller sj. can chronic ankle instability be prevented? rethinking management of later ankle sprains. j athl train 2002;37(4):430-435. 9. santos mj, lui w. possible factors related to functional ankle instability. j orthop sports phys ther 2008;38(3):150-157. 10. cook jl, purdam cr. is tendon pathology a continuum? a pathology model to explain the clinical presentation of load-induced tendinopathy. br j sports med 2008;43:409-416. 11. van der wees pj, hendriks ejm, jansen mj, van beers h, de bie ra, dekker j. adherence to physiotherapy clinical guideline acute ankle injury and determinants of adherence: a cohort study. biomed central mus dis 2007;8:45. [http://dx.doi. org/10.1186/1471-2474-8-45] 12. olerud c, molander h. a scoring scale for symptom evaluation after ankle fracture. arch orthop trauma surg 1984;103:190-194. [http://dx.doi.org/10.1007/ bf00435553] 13. van dijk cn. management of the sprained ankle. br j sports med 2002;36:83-84. 14. susco tm,valovich mcleod tc, gansneder bm, schultz sj. balance recovers within 20 minutes after exertion as measured by the balance error scoring system. j athl train 2004;39(3):241-246. 15. kovaleski je, norrell pm, heitman rj, hollis jm, pearsall aw. knee and ankle position, anterior drawer laxity, and stiffness of the ankle complex. j athl train 2008;43(3):242-248. [http://dx.doi.org/10.4085/1062-6030-43.3.242] 16. trojian th, mckeag db. ankle sprains: expedient assessment and management. phys sports med 1998;26:1-12. appendix i a pilot study was performed to establish the clarity and reliability of the olerud and molander questionnaire, as well as the clinical tests for mechanical instability. inter-rater reliability was tested so that one tester, namely the first author, would be reliable and able to conduct all the tests. inter-rater reliability was established by using the researcher and an assistant to assess the 2 mechanical tests on 14 players from a team not involved in the main study on the same day in 2 separate testing rooms, so that they were blinded to the results scored by the other. the researcher tested a player, and then the player went to the other room where the assistant tested the player until all 14 players had been tested. the researcher then repeated the tests 4 days later in the same manner, blinded to the initial results, to establish intra-rater reliability. the researcher and the assistant physiotherapist agreed on all subjects for both mechanical tests performed. http://dx.doi.org/10.1136/bjsm.37.4.291] http://dx.doi.org/10.1136/bjsm.37.4.291] http://dx.doi.org/10.1177/0363546508322889] http://dx.doi.org/10.1177/0363546508322889] http://dx.doi.org/10.1136/bjsm.36.4.265] http://dx.doi.org/10.1136/bjsm.36.4.265] http://dx.doi.org/10.1136/bjsm.34.5.348] http://dx.doi.org/10.1136/bjsm.34.5.348] http://dx.doi.org/10.1186/1471-2474-8-45] http://dx.doi.org/10.1186/1471-2474-8-45] http://dx.doi.org/10.1007/bf00435553] http://dx.doi.org/10.1007/bf00435553] http://dx.doi.org/10.4085/1062-6030-43.3.242] position statement sajsm vol 24 no. 2 2012 69 introduction this position statement is based on a review of available evidence and international guidelines on exercise in pregnancy and in the postpartum period. it aims to assist pregnant women and their care providers in assessing the merits and benefits of improving and maintaining fitness during this period. there are many concerns about exercise during pregnancy, with medical advice historically dissuading women from continuing or initiating regular exercise programmes. however, research has shown that high levels of exercise are not associated with an increased incidence of negative events such as infertility, miscarriage, congenital malformation, premature labour, premature rupture of the membranes, placental abruption, cord entanglement, fetal distress, abnormal labour, significant growth restriction or maternal injury.1 currently, many women of childbearing age wish to continue with their exercise programmes during pregnancy. appropriate guidance and exercise counselling by the attending care provider can fulfil this need. recommendations in support of the guidelines set out by the american college of obstetricians and gynecologists (acog),2 the society of obstetricians and gynaecologists of canada (sogc) and the canadian society of exercise physiology,3 this statement suggests the following: in the absence of either medical or obstetric complications, all pregnant women should be encouraged to participate in aerobic and strength-conditioning training at a moderate intensity on most or all days of the week. reasonable goals of aerobic conditioning should be to maintain a good fitness level throughout pregnancy without trying to reach peak fitness or train for an athletic competition. activities that will minimise the risk of loss of balance and fetal trauma should be chosen by pregnant women wishing to exercise. these include a wide range of activities that minimise the risk of falling and abdominal injury, such as walking, jogging/running, hiking, lowimpact aerobics, swimming, cycling – stationary/spinning, rowing, cross-country skiing and dancing. high-risk activities include contact and collision sports, vigorous racquet games, gymnastics, horseback riding, skating, skiing (snow and water), hang gliding and scuba diving. women should be advised that adverse pregnancy or neonatal outcomes are not increased for exercising women. initiation of pelvic floor exercises in the immediate postpartum period may reduce the risk of future urinary incontinence. women should be advised that moderate exercise during lactation does not affect the quantity or composition of breastmilk or impact on infant growth. contra-indications to exercise in pregnancy2,3 absolute contra-indications • haemodynamically significant heart disease • restrictive lung disease • incompetent cervix/cerclage • multiple gestation at risk for premature labour (>triplets) abstract there are many concerns about exercise during pregnancy, with medical advice historically dissuading women from continuing or initiating regular exercise programmes. however, research has shown that high levels of exercise are not associated with an increased incidence of negative events. currently, many women of childbearing age wish to continue with their exercise programmes during pregnancy. appropriate guidance and exercise counselling by the attending care provider can fulfil this need. this position statement aims to assist pregnant women and their care providers in assessing the merits and benefits of improving and maintaining fitness during this period. s afr j sm 2012;24(2):69-71. etti barsky, trudy smith, jon patricios, robert collins, andrew branfield, maaki ramagole section sports medicine, department of health sciences, university of pretoria, and preggi bellies south africa etti barsky, mb bch, msc (sports med) university of the witwatersrand and charlotte maxeke johannesburg academic hospital trudy smith, mb bch, fcog (sa) section sports medicine, department of health sciences, university of pretoria, and morningside sports medicine, johannesburg jon patricios, mb bch, mmedsci, facsm, ffsem (uk) section sports medicine, department of health sciences, university of pretoria robert collins, mb bch, msc (sports med) maaki ramagole, mb chb, msc (sports med) the centre for sports medicine and orthopaedics, johannesburg andrew branfield, mb bch, mspmed (unsw) corresponding author: j patricios (jpat@mweb.co.za). south african sports medicine association position statement on exercise in pregnancy 70 sajsm vol 24 no. 2 2012 • persistent secondor third-trimester bleeding • placenta praevia after 26 weeks’ gestation • ruptured membranes • preterm labour • pre-eclampsia • uncontrolled type 1 diabetes, thyroid disease or other serious systemic disorders, e.g. chronic bronchitis, uncontrolled seizures. relative contra-indications • anaemia (defined by the world health organization as <10 g/dl in pregnant women) • unevaluated maternal cardiac arrhythmia • extreme morbid obesity • extreme underweight (bmi <12) • intra-uterine growth restriction in current pregnancy • poorly controlled hypertension • orthopaedic limitations, such as degenerative joint disease and joint instabilities. exercise prescription as with all treatment that is prescribed, the risk-benefit balance needs to be assessed. in the case of exercise during pregnancy, the risk of a sedentary lifestyle is likely to be more detrimental than an active one. the effects of not exercising during pregnancy include loss of muscular and cardiovascular fitness, excessive maternal weight gain, raised risk of gestational diabetes or pre-eclampsia, development of varicose veins and increased risk of physical complaints such as dyspnoea, lower back pain and poor psychological adjustment.4 because of the various physiological and anatomical changes that occur during pregnancy, the type of exercise chosen by pregnant women needs to be: • safe – there should be minimum injury risk to both mother and fetus • comfortable – especially as the pregnancy progresses. one also needs to consider the type, intensity, duration and frequency of exercise sessions in order to balance potential benefits with potential risks. forms of exercise as in the general population, developing and improving fitness with both cardiovascular exercises and strength training exercises is recommended in pregnancy.3,5 a wide range of activities such as walking, jogging/running, hiking, low-impact aerobics, swimming, cycling – stationary/ spinning, rowing, cross-country skiing and dancing have not been shown to have any adverse effects in pregnant women. however, in the presence of pelvic instability symptoms, i.e. posterior pelvic pain, sacro-iliac joint pain or pelvic girdle pain, activities such as walking may aggravate the condition.6,7 the type of exercise prescribed needs to be individualised in accordance with the woman’s skills, abilities and preference. there is general consensus that the following activities should be avoided in pregnancy: • scuba diving. both mother and fetus are at increased risk of decompression sickness at all stages of pregnancy. furthermore, the fetus is at risk of potential congenital defects. maternal risks include gastro-oesophageal reflux, reduced inspiratory reserve, and poor equalisation due to pregnancy-related swelling of the mucosa. there is also a potential risk for miscarriage, particularly if there has been a previous history thereof.8 • exercise at altitude greater than 6 000 feet, which places too much hypoxic stress on the mother. • contact or falling. any activities that have a greater risk for contact or falling and could therefore result in trauma to the mother or fetus, e.g. soccer, gymnastics. • motionless standing. there is a decrease in cardiac output in this position. because of compression of the vena cava by the gravid uterus, some women may show signs of symptomatic hypotension in the supine position after 16 weeks of pregnancy. exercise in a supine position therefore remains controversial. it would consequently be prudent to limit exercise in the supine position and also to advise the patient that should she experience dizziness in this position, an alternate exercise needs to be performed.1-5,7 research on strength training is limited; however, consensus is that using relatively low weights through a dynamic range of movement is a safe and effective form of resistance training. conditioning exercises help maintain posture and prevent low back pain. one needs to pay attention to correct technique, including correct breathing and avoiding valsalva manoeuvres.5,9 exercise intensity intensity is the most difficult and controversial element of a pregnant woman’s exercise regimen. much attention has been paid to limiting the heart rate to restrict ‘adverse effects’. however, current recommendations are more liberal than is commonly known. it has been shown that as a result of the variability of maternal heart rate responses to exercise, target heart rates cannot be used to monitor exercise intensity in pregnancy. an upper level of safe exercise intensity has not been established and the center for disease control (cdc) and american college of sports medicine (acsm)’s definitions of moderate exercise of 3 4 mets (metabolic equivalent where 1 met=3.5 ml o2 consumed/kg body weight/minute)10 or any activity that is equivalent in intensity to brisk walking can also be applied in pregnancy.1,5,9 in a meta-analysis study of exercise and pregnancy, it was reported that with exercise intensities of 81% of maximum heart rate, no significant adverse effects were found.7 likewise, the acog guidelines has no heart rate limitation and therefore also supports a more liberal approach.2 an alternative to heart rate for monitoring exercise intensity, is the rate of perceived exertion. the borg scale is commonly used, whereby a score of 12 14 on a 6 20 scale indicates a ‘somewhat hard’ workout.3,5 in conclusion, current guidelines for exercise intensity in pregnant women recommend performing exercise that minimises hypoxic stress and the risk of abdominal injury, maintaining a heart rate between 55% and 70% of predicted maximum or a rating of perceived exertion between 12 and 14 (‘somewhat hard’). exercise duration and frequency of concern is the potential for overheating with prolonged duration of training and the subsequent teratogenic effects of hyperthermia in the first trimester. to date, this has not been shown to occur in studies of exercising women.3 even so, exercise should preferably take place in a well-ventilated and temperature-controlled environment. take note of hydration and subjective feelings of overheating. according to acsm and acog guidelines, training sessions that accumulate to 30 60 minutes per day are not unreasonable. they sajsm vol 24 no. 2 2012 71 further recommend that in the absence of medical or obstetric contraindications, exercise may be performed on all or most days of the week. warning signs it is important to educate pregnant women about the warning signs that should signal an immediate end to training. these include:2 • vaginal bleeding • dyspnoea before exertion • dizziness • headache • chest pain • muscle weakness • calf pain or swelling (need to exclude thrombophlebitis or dvt) • preterm labour • decreased fetal movements • amniotic fluid leakage. these symptoms and signs warrant urgent gynaecological and/or medical attention. competitive athletes elite athletes need to be educated about the decrease in performance that occurs with pregnancy as a result of weight gain and musculoskeletal changes. nonetheless, training may continue during pregnancy provided the athlete pays particular attention to adequate hydration, additional caloric energy requirements and dangers of heat stress. closer obstetric supervision is required.5,9 postpartum exercise resuming exercise postnatally depends largely on the mode of delivery. an uncomplicated vaginal delivery allows for a return to a mild exercise programme almost immediately. a delivery by caesarean section requires a 6-week recovery period before exercise is commenced. breastfeeding women should be advised of adequate breast support, and that exercise will not compromise milk supply, latching or infant growth.11 special attention needs to be paid to pelvic floor-strengthening exercises. patients need to be reminded that exercise needs to be stress relieving and not stress provoking. conclusion current consensus in both obstetrics and sports medicine suggests that exercising during pregnancy results in minimal risk and numerous shortand long-term benefits for both mother and baby. hence, while acknowledging the significant anatomical, physiological and psychological changes of pregnancy, a healthy woman with an uncomplicated pregnancy should be encouraged to maintain and improve her fitness within the recommended guidelines. references 1. clapp jf 3rd. recommending exercise during pregnancy. contemporary obstetrics and gynecology 2001;46(1):30-53. 2. acog committee opinion no. 267. american college of obstetricians and gynecologists. obstet gynecol 2002;99:171-173. 3. joint sogc/csep clinical practice guideline 2003 (june) no.129. available at http://www.sogc.org/guidelines/public/129e-jcpg-june2003.pdf (accessed 15 september 2011). 4. royal college of obstetricians and gynaecologists. exercise in pregnancy. statement no. 4. january 2006. http://www.rcog.org.uk/womens-health/clinical-guidance/ exercise-pregnancy (accessed 23 june 2011) . 5. artal r, o’toole m. guidelines of the american college of obstetricians and gynecologisits for exercise during pregnancy and the postpartum period. br j sports med 2003;37:6-12. 6. larsen ec,wilken-jensen c, hansen a, et al. symptom-giving pelvic girdle relaxation in pregnancy. ii: symptoms and clinical signs. acta obstet gynecol scand 1999;78(2):111-115. 7. östgaard hc. assessment and treatment of low back pain in working pregnant women. semin perinatol 1996;20(1):61-69. 8. kayle a. safe diving a medical handbook for scuba divers. struik, cape town, 2nd edition 2009: 34-35 9. olson d, sikka rs, hayman j, novak m, stavig c. exercise in pregnancy. curr sports med rep 2009;8 (3):147-153. 10. pate rr, pratt m, blair sn, et al. a recommendation from the centers for disease control and prevention and the american college of sports medicine. jama 1995;273:402-407. 11. clapp jf 3rd. exercise through your pregnancy. omaha, nebraska: addicus books, 2002:79. km_c227-20180511093545 original research 1 sajsm vol. 30 no. 1 2018 analysis of sports science perceptions and research needs among south african coaches a kubayi,1,2 dphil; y coopoo,2 dphil, facsm; a toriola,1 phd 1 department of sport, rehabilitation and dental sciences, faculty of science, tshwane university of technology, pretoria, south africa 2 department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa corresponding author: a kubayi (kubayina@tut.ac.za) sports science is a discipline that studies the processes used to guide the practice of sport with the primary goal of enhancing performance [1] and reducing the risk of injury. [2] sports science research benefits from two worlds of science, namely, pure and applied. the former serves to expand and explore the nature of things and forms the basic framework upon which all practical knowledge develops; the latter deals with the integration and application of science to the phenomenon of sport (e.g. sports biomechanics, exercise physiology, sports nutrition, and exercise/sports psychology). [3] it is in the applied form that sports scientists provide answers to the questions that are often asked by coaches and technical personnel in the important areas of talent identification, physical fitness, monitoring, team selection, and training methods. the applied sciences are beneficial for the large number of sports scientists who provide vital support to the athlete. [3] whilst basic research in sports science is predominantly performed by academics and usually published, applied research may result in a publication, but the real-world outcome it produces is one that is relevant to sports or can be applied in the sporting environment in order to improve an athlete’s performance or reduce the incidence of injury.[2] haff [4] describes sports science as an applied rather than a basic science as it is a combination of development, research, innovation, and application. bishop et al. [2] reported that the application of sports science occurs if the coach and/or scientist uses the information obtained from such research to intervene realistically in the training and/or performance of an athlete. sports science research, therefore, should address questions that have the potential to improve performance. [2] sports coaches need to have a foundation of sports science knowledge in order to enhance athletes’ performance. therefore, coaches should steep themselves in the scientific and technological aspects of sports so that they can help the athletes to improve their skills. as haff [4] purported, coaches need to have a basic understanding of nutrition, biomechanics, physiological adaptations of training, and scientific principles that form a foundation of training, but they also need to understand the research process. haff [4] further contended that coaches also need to have some basic sports science training because they are the end users of the sports science information, and with basic knowledge in that area they can make objective judgments in their coaching process rather than solely relying on their personal experiences as coaches and/or former athletes. several studies have been conducted on the perceived sports science needs among coaches in other countries. examples of such studies are those conducted in australia, [5] canada, [6] and and turkey [7]. kilic and ince [7] observed that these studies have made significant positive impacts in transmitting relevant scientific knowledge to the coaches and the athletes. however, from a south african standpoint, there appears to be a discrepancy between coaches’ expectations concerning their needs and the focus of the findings published by sports scientists. it is, therefore, important to know how sports science research could better meet the actual needs of coaches and better fit into their coaching practice. methods experimental design this study adopted a cross-sectional survey design. participants a total of 202 (28 females and 174 males) sports coaches, aged 18 to 60 years (mean age: 32 years), were purposively recruited to participate in this study. the participants were selected on the basis that they were coaching priority sports as categorised by the department of sport and recreation. background: there appears to be a gap between coaches’ expectations concerning their needs and the focus of research findings published by sports scientists. given the important role of sports science in enhancing athletic performance, closing the gap between sports scientists and coaches is expedient. objectives: to investigate sports science perceptions and research needs among south african coaches. methods: using a cross-sectional survey design, a total of 202 (28 females and 174 males) purposively recruited south african coaches completed a validated questionnaire. results: findings indicated that improving the technique/efficiency of athletes (4.3±0.8), reducing the incidence of injury/illness in athletes (4.3±0.8), helping athletes peak for competition (4.3±0.9), and the mental preparation of athletes (4.3±1.0) were reported as the most preferred areas of research by coaches. the coaches also reported that there is a need/role for sports science researchers to translate scientific literature into easily understandable language (3.9±1.0). the coaches also indicated that the knowledge of sports science was important for them in performing their roles as coaches (3.9±1.0). conclusion: these findings have practical implications for sports federations to revise their coach education programmes to include sports science concepts which can be applied by coaches to improve the sports performance of individual athletes and teams. keywords: coaching, performance, knowledge s afr j sports med 2018;30:1-4. doi: 10.17159/2078-516x/2018/v30i1a4240 mailto:kubayina@tut.ac.za http://dx.doi.org/10.17159/2078-516x/2018/v30i1a4240 original research sajsm vol. 30 no. 1 2018 2 research instrument a questionnaire adapted from williams [8] was used to gather information about coaches’ perceptions of their sports science and research needs. some of the items were modified to ensure suitability and applicability to the south african context. the questionnaire consisted of the following four areas: preference for research needs, qualities valued in coaching, practical application of sports science, and coach education and knowledge. all items were scored on a five-point likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). in order to determine the reliability of the questionnaire, the cronbach alpha was computed which yielded a coefficient of 0.90. data collection procedure prior to data collection, this study received clearance from the ethics committee of the university of johannesburg. informed consent was sought from the participants after the purpose of the study and data collection procedures were clearly explained to them. the principal researcher and trained fieldworkers administered the questionnaires to the participants, who were guided to complete the instrument independently. it took not more than 10 minutes to complete the questionnaires. statistical analysis descriptive statistics methods such as, means and standard deviations, were used to analyse the data. the data collected were initially tested for normality of distribution before the actual analysis. the independent t-test was applied to examine significant differences between experienced and inexperienced coaches. effect size (es) values of 0.2, 0.5, and 0.8 represented small, medium, and large differences, respectively. [9] the alpha level was set at 0.05. statistical analyses were performed using the statistical package for social sciences (spss – version 24). results table 1 shows the most preferred areas of research according to coaching experience. the most preferred areas of research reported by sports coaches were “improving the technique/efficiency of athletes” (4.3±0.8), “reducing the incidence of injury/illness in athletes” (4.3±0.8), “helping athletes peak for competition” (4.3±0.9), and “mental preparation of athletes” (4.3±1.0). statistically significant differences between the mean values of experienced and inexperienced coaches on the items “reducing the incidence of injury/illness in athletes” (t [188] = –1.970, p = 0.0, es = 0.3) and “mental preparation of athletes” (t [188] = –2.058, p = 0.0, es = 0.3) were found. the qualities most valued by sports coaches were as follows: “keeping up-to-date with the latest developments in coaching” (4.2±0.9), “improving my educational qualifications” (4.2±0.9), “success of athletes under my supervision” (4.2±0.8) and “having a good rapport with my athletes” (4.1±0.9) (see table 2). there were significant differences in the mean scores for inexperienced and experienced coaches on the following items: “using the latest methods/technology” (t [190] = –2.317, p = 0.0, es = 0.3) and “many years of coaching experience “(t [189] = – 2.368, p = 0.0, es = 0.3). table 3 shows the practical application table 1. preference for research areas all iec ec variable mean ± sd mean ± sd mean ± sd effect size pvalue improving the technique/ efficiency of athletes 4.3±0.8 4.3±0.8 4.4±0.8 0.1 0.2 reducing the incidence of injury/illness in athletes 4.3±0.8 4.2±0.8 4.4±0.7 0.3 0.0* helping athletes peak for competition 4.3±0.9 4.2±0.9 4.4±0.8 0.2 0.0 mental preparation of athletes 4.3±1.0 4.1±1.0 4.4±0.9 0.3 0.0* development of recovery techniques for athletes 4.3±0.9 4.2±0.9 4.3±0.9 0.1 0.2 the development of strength/ power in athletes 4.2±0.9 4.2±1.0 4.3±0.8 0.1 0.3 enhanced aerobic stamina of athletes 4.1±1.0 4.0±1.0 4.2±1.0 0.2 0.2 speed recovery from injury 4.0±1.0 3.9±1.1 4.1±1.0 0.2 0.2 nutrition supplementation for athletes 3.9±1.1 3.8±1.2 4.1±1.0 0.3 0.1 weight control for athletes 3.9±1.0 3.8±1.0 4.0±1.0 0.2 0.3 * significant at p<0.05. iec, inexperienced coaches; ec, experienced coaches table 2. qualities valued in coaching all iec ec variable mean ± sd mean ± sd mean ± sd effect size pvalue keeping up-to-date with the latest developments in coaching 4.2±0.9 4.1±1.0 4.3±0.8 0.2 0.1 improving my educational qualifications 4.2±0.9 4.2±1.0 4.3±0.9 0.1 0.6 success of athletes under my supervision 4.2±0.8 4.1±1.0 4.3±0.9 0.2 0.1 having a good rapport with my athletes 4.1±0.9 4.0±1.0 4.2±0.9 0.2 0.1 having a good rapport with support personnel (including sport scientists) 4.0±0.9 3.9±0.9 4.1±0.9 0.2 0.1 using the latest methods/ technology (where proven) 4.0±1.0 3.8±1.0 4.1±0.9 0.3 0.0* many years of coaching experience 3.7±1.0 3.6±0.9 3.9±1.0 0.3 0.0* being a former elite athlete 3.6±1.1 3.7±1.4 3.5±1.2 0.2 0.3 keeping up-to-date with the latest developments in coaching 4.2±0.9 4.1±1.0 4.3±0.8 0.2 0.1 improving my educational qualifications 4.2±0.9 4.2±1.0 4.3±0.9 0.1 0.6 * significant at p<0.05. iec, inexperienced coaches; ec, experienced coaches original research 3 sajsm vol. 30 no. 1 2018 of sports science research according to coaching experience. sports coaches rated the following as the most important items: “technical aspects of coaching need to be based on sports science/sports medicine research” (3.7±0.9), “i need more research that is based in ‘natural’ settings” (3.7±0.9) and “sports science/sports medicine research influences what i do with the athletes” (3.7±1.0). significant differences were found in the following variables: “i need more research that is based in ‘natural’ settings” (t [190] = –2.151, p = 0.0, es = 0.2) and “sports science/sports medicine research influences what i do with the athletes (t [190] = –1.961, p = 0.0. es = 0.3). table 4 summarises results for coach education and sports science knowledge according to coaching experience. sports coaches indicated that “there is a need/role for sports science researchers to translate scientific literature into easily understandable language” (3.9±1.0) and “sports science knowledge is important for me to be a good coach” (3.9±1.0). discussion this study found that improving the technique/efficiency of athletes was identified as the most important area of interest by sports coaches. this finding is congruent with that of previous studies which perceived biomechanics as the scientific domain of most benefit to coaches. [8, 10] reducing the incidence of injury/illness in athletes and helping them peak for competition were the other imperative factors identified as beneficial to coaches. the literature indicates that peaking for competition entails the physiological manipulation of training intensity and volume based on the principle of periodisation.[8] therefore, it could be deduced that with an improvement in technical skills, a discipline addressed in biomechanics and physiology, is related to reducing the incidence of injury. [8] the reason why sports coaches stressed the priority of reducing the frequency of injury/illness among athletes could be that the majority of them were involved in contact sports (e.g. rugby, soccer, etc.) which have a higher occurrence of injuries. the preference for physiology-based research may be twofold: firstly, the fundamental requirements of most sports is for athletes to develop appropriate aerobic and anaerobic fitness, and secondly, researchers work more in the area of physiology than in other areas, such as sports medicine and sports physiotherapy. [5] another important area of benefit which emerged from this study relates to the mental preparation of athletes. previous research [7] reported that sports coaches had limited knowledge of mental preparation for athletes despite it being very necessary. nevertheless, in line with the assertion of william and kendall [5], there are few sports psychologists working with highperformance athletes in south africa, and they focus mainly on servicing the athletes rather than on conducting research based in the natural setting. sports coaches indicated that keeping up to date with the latest developments and research in coaching was very important, which complemented the findings in the literature [4] coaches who keep up to date with the latest developments in their particular sports may be more receptive to trying new ideas through research which would in turn assist in maximising their athletes’ performance. [8, 11] sports coaches also indicated the importance of improving their educational qualifications as part of their continuous professional development. those who did not play at the professional level are denied opportunities to work at a high-performance level in south africa. [12] the success of athletes under a coach’s supervision was also regarded as the most important aspect in coaching, especially in south africa. the high emphasis placed on “having a good rapport with my athletes” acknowledges the importance of having good professional relationships between coaches and athletes, as well as a valuing of interpersonal skill above the need for scientific knowledge. [6] in contrast to previous research that found that many years of coaching experience was an important quality valued in coaching, [9] the present study table 3. practical application of sports science research all iec ec variable mean ± sd mean ± sd mean ± sd effect size pvalue technical aspects of coaching need to be based on sports science/sports medicine research 3.7±0.9 3.7±0.9 3.8±0.8 0.1 0.1 i need more research that is based in ‘natural’ settings 3.7±0.9 3.6±0.9 3.9±1.9 0.2 0.0* sports science/sports medicine research influences what i do with the athletes 3.7±1.0 3.5±0.9 3.8±1.0 0.3 0.0* performance-based research is only of value to me if my athletes participated in the study 3.4±1.1 3.4±1.1 3.4±1.1 0.0 0.9 sports science researchers do not need to have coaching experience 3.0±1.3 2.9±1.3 3.1±1.3 0.2 0.3 * significant at p<0.05. iec, inexperienced coaches; ec, experienced coaches table 4. coach education and sports science knowledge all iec ec variable mean ± sd mean ± sd mean ± sd effect size pvalue there is a need/role for sports science researchers to translate scientific literature into easily understandable language 3.9±1.0 3.9±1.0 4.0±1.1 0.1 0.2 sports science knowledge is important for me to be a good coach 3.9±1.0 3.9±1.0 3.9±1.0 0.0 0.9 i should have enough scientific knowledge to be able to read sports science journals 3.7±1.0 3.7±0.9 3.7±1.1 0.0 0.12 sports science research takes too long to answer coaching questions 3.3±1.0 3.3±0.9 3.3±1.1 0.0 0.6 * significant at p<0.05. iec, inexperienced coaches; ec, experienced coaches original research sajsm vol. 30 no. 1 2018 4 found that coaching experience was the least important of the qualities reported by sports coaches. the fact that south african coaches are not hired and promoted based on their many years of coaching but on their qualifications probably explains this finding. sports coaches agreed that the technical aspects of coaching need to be based on sports science/sports medicine research. this finding demonstrates that there appears to be a huge gap between what researchers are doing and the knowledge that coaches need. this statement is supported by reade et al. [7] who reported that there are gaps between the focus of sports science research and coaches’ expectations. this finding has implications for policymakers and sports researchers to reinforce existing consultative discussion to determine the needed research focus. [9] therefore, this study demonstrates that sports scientists and coaches should work together to integrate research into practice to address coaching problems. a sports science researcher should be guided by the philosophy in which useful findings are provided that could enhance the development of athletes and coaches, as development is synonymous with a successfully integrated research-practice model. [13] coaches further indicated that there is a need for sports scientists to translate scientific journals into easily understandable language, a finding that supports previous literature. [5, 8] admittedly, most coaches are unfamiliar with research methodology, statistics, jargon, concepts and terminologies often used by sports scientists, and they lack the basic background knowledge of sports science and/or necessary educational background to interpret research findings and apply the latest information to coaching practice. if the results of sports science research are not presented in understandable ways, they cannot be properly applied to address practical issues in sports coaching. there is a need for the better translation and dissemination of sports science information so that it is easily understood by coaches. this could be achieved through organising workshops, seminars, and short learning courses targeted at sports scientists and coaches. [14, 15] the coaches further reported that sports science knowledge is important for them to be good coaches and that they should have sufficient scientific background to be able to read sports science journals. in addition, the coaches agreed that it takes too long for sports science research to answer issues related to the practical aspects of coaching. this could be attributed to the fact that sports science investigations generally require long-term data collection. [4] bishop et al. [2] contend that it does not matter how long sports scientists take to collect data, the most important thing is that they should put into practice the information obtained from the research process to improve the performance and/or training of an athlete. conclusion based on the outcome of this study, the coaches indicated a dire need for research in the following areas: improving the technique/efficiency of athletes, reducing the incidence of injury/illness in athletes, helping athletes peak for competition, and the mental preparation of athletes. furthermore, coaches reported that sports scientists should present scientific articles in language which is user-friendly. thus, it is imperative to organise sports science workshops and seminars regularly for coaches to keep them abreast with the latest trends and developments in coaching. references 1. bishop d. an applied research model for the sport sciences. sports med 2008; 38(3): 253–263. [doi:10.2165/00007256200838030-00005] 2. bishop d, burnett a, farrow d, et al. sports-science roundtable: does sports-science research influence practice. int j sports physiol perform 2006; 1(2): 161–168. [doi:10.1123/ijspp.1.2.161] 3. amusa lo, toriola al. challenges for african sports scientists: bridging the gap between theory and practice. afri j phys health educ recreat dance 2004; 10(1): 1–19. 4. haff gg. sport science. strength cond j 2010; 32(2): 33–45. [doi: 10.1519/ssc.0b013e3181d59c74] 5. williams sj, kendall l. perceptions of elite coaches and sports scientists of the research needs for elite coaching practice. j sports sci 2007; 25(14): 1577–1586. [doi10.1080/02640410701245550] 6. reade i, rodgers w, hall n. knowledge transfer: how do high performance coaches access the knowledge of sport scientists? int j sports sci coach 2008; 3(3): 319–334. [doi:10.1260/174795408786238470] 7. kilic k, ince ml. use of sports science knowledge by turkish coaches. int j exerc sci 2015; 8(1): 21–37. 8. williams sj. a case study of the relationship between sports science research practice and elite coaches perceived needs. unpublished doctoral thesis. university of canberra, 2005. http://www.canberra.edu.au/researchrepository/items/0de68d3b -025b-da67-44dc-f4551a12f504/1/ 9. cohen j. statistical power analysis for the behavioral sciences (2nd ed.). hillsdale, nj: lawrence erlbaum, 1988:20–26. 10. mooney r, corley g, godfrey a, et al. analysis of swimming performance: perceptions and practices of us-based swimming coaches. j sports sci 2016; 34(11): 997–1005. [doi:10.1080/02640414.2015.1085074] 11. williams j. what are the research needs of elite coaches? australian sports commission 2006; 29(2). https://ausport.gov.au (accessed 16 june 2017). 12. kubayi na, coopoo y, morris-eyton hf. job-related barriers encountered by football coaches in gauteng province of south africa: management and governance – sport management and governance. afri j phys health educ recreat dance 2015; november (suppl. 1): 160-166. 13. jones b, till k, emmonds s, et al. accessing off-field brains in sport; an applied research model to develop practice. br j sports med 2016; pii: bjsports-2016-097082. [doi:10.1136/bjsports-2016097082] 14. hendricks s, sarembock m, jones b, et al. the tackle in south african youth rugby union–gap between coaches' knowledge and training behaviour. int j sports sci coach 2017; 12(6): 708– 715. [doi:10.1177/1747954117738880] 15. hendricks s, sarembock m. attitudes and behaviours of top-level junior rugby union coaches towards the coaching of proper contact technique in the tackle-a pilot study. s afr j sports med 2013; 25(1): 8–11. [doi:10.7196/sajsm.459] km_c227-20180517092727 introduction racial disparities have been demonstrated in athletic performance 1 and in the predisposition towards specific diseases. 2 immune/inflammatory pathways may be important in the pattern and/or progression of disease. 3,4 research has demonstrated differences in the level of circulating immune/inflammatory markers as well as genotypic differences which may help to explain disease predisposition in specific racial groups. 3,4 in contrast, there is limited information relating to immune/inflammatory responses to exercise between racial groups. such information is particularly relevant – strenuous exercise has been shown to alter immune/inflammatory responses predisposing athletes to infection and possibly injury, 5 which would ultimately impact on training and performance. eccentric and/or strenuous unaccustomed exercise has been shown to elicit changes in skeletal muscle morphology. 6 these changes are typically accompanied by increases in circulating creatine kinase (ck), local muscle swelling and soreness as well as alterations in circulating inflammatory markers such as leucocytes and cytokines. 7-9 based on these observations, researchers have utilised exercise, particularly eccentrically biased exercise, to induce muscle damage and investigate immune/inflammatory sequelae. the key components of innate and adaptive immunity are the complement system and immunoglobulins, respectively. the complement system is composed of a number of proteins that are intricately involved in a variety of immune-related functions. complement has been described as an important role player in cellular activation, chemotaxis, inflammation and clearance of immune complexes. 10-12 immunoglobulins are crucial components of humoral immunity, having pathogen neutralisation and original research article complement, immunoglobulin and creatine kinase response in black and white males after muscle-damaging exercise abstract objectives. to determine the effect of eccentrically biased exercise and ethnic group on circulating levels of complement, immunoglobulin creatine kinase. seven black and 8 white males (18 – 22 years), active but untrained, participated in the study. subjects performed a 60-minute downhill run on a treadmill (gradient –13.5%) at a speed eliciting 75% of their vo2 peak on a level grade. venipunctures were performed before, immediately after and then at 3, 6, 9, 12, 24, 48, and 72 hours afterwards. plasma creatine kinase (ck) activity, serum complement (c3, c4) and immunoglobulin (total igg, igg1, igg2, igg3, igg4, iga) concentrations were compared using a repeated measures anova. results. there was an interaction (p=0.0055) and ethnic group effect (p<0.0001) for ck activity with consistently higher levels in the black group. ck increased over time after the run, peaking at 12 h for both groups. c3, c4, total igg, igg1, igg3, and iga were significantly higher (ethnic group effect, p<0.001), and igg2 significantly lower (ethnic group effect, p<0.001) in the black group. significantly higher resting concentrations of total igg (+21%), and igg1 (+32%) were observed in this group. correspondence: andrew j mckune discipline of sport science school of physiotherapy, sport science and optometry faculty of health sciences university of kwazulu-natal private bag x54001 durban, 4000 south africa tel.: +27 (0)31 2607985 fax: +27 (0)31 260 7903 cell: +27 (0)837155683 e-mail: mckunea@ukzn.ac.za andrew j mckune (dtech)1 stuart j semple (dtech)2 lucille l smith (phd)3 ahmed a wadee (phd)4 1 discipline of sport science, school of physiotherapy, sport science and optometry, university of kwazulu-natal, durban 2 faculty of education, health and science, charles darwin university, darwin, australia 3 department of sport, rehabilitation and dental sciences, tshwane university of technology, pretoria 4 department of immunology, university of the witwatersrand, johannesburg conclusions. ck was significantly elevated in the black group although the relative response to exercise in whites was higher, suggesting greater muscle damage. differences in the concentration of complement proteins and immunoglobulins suggest a heightened immunological/inflammatory milieu in the circulation of the black group. the performance and health implications of this finding warrant further investigation. sajsm vol 21 no. 2 2009 47 opsonisation functions that occur during primary and/or secondary antibody responses. they also regulate cellular cytotoxic activity via sensitisation of natural killer cells, phagocytes, and mast cells, 10-12 and promote inflammatory responses and the clearance of immune complexes via activation of the complement system. 10,11 owing to methodological considerations there are inconsistencies within the literature concerning complement and immunoglobulin response to bouts of strenuous exercise. in addition, there is limited information relating to the circulating levels of these proteins in different racial groups at rest as well as in response to strenuous exercise. therefore, the first aim of this study was to determine if complement proteins and immunoglobulins are elevated in response to exercise-induced muscle damage. secondly, inducing this form of benign injury provided the opportunity to investigate if black and white males respond differently to exercise-induced muscle damage. method participants active, untrained white (n=8) and black (n=7) males participated in the study. screening to determine each participant’s level of activity and training was performed using the fit (frequency intensity time) index of kasari. 13 this index requires that points are allocated depending on the frequency, intensity and time spent performing physical activity per week with scores ranging from 1 (minimum activity) to 100 (training at a high intensity every day of the week). individuals were included in the study if their fit index ranged from 8 to 10. these are individuals who perform a few days of moderate-intensity physical activity per month, with a duration of 20 30 minutes per session. the white males were from british or dutch european descent, the two groups accounting for the majority of cultural variation in south africa. the black participants were assumed to be of xhosa ethnicity, based on the stated first language reported from both parents. based on their self-reported medical history questionnaire, participants were excluded from the study if they exhibited any form of lower-extremity disability/injury that may have been exacerbated by physical activity, and if they were on any anti-inflammatory medication. in order to control for acute illness before, during and after the downhill run, which could affect the immune variables measured in the study, participants completed the wisconsin upper respiratory symptom survey (wurss). 14 the wurss is a validated, evaluative, illness-specific quality-of-life instrument, designed to assess the negative impact of the common cold. the survey examines the presence and level of severity of 32 upper respiratory tract symptoms such as a runny nose, sneezing, sore throat and cough. the survey was completed every day for a week before the downhill run, on the day of the run, and every day for a week after the run. all the participants signed an informed consent form approved by the tshwane university of technology ethics committee. body composition height and weight were recorded using a calibrated medical height gauge and balance scale (detecto, webb city, usa). a harpenden skinfold caliper was used for skinfold measurements (7 sites) to assess per cent body fat (table i) using the drinkwater-ross method. 15 assessment of vo2 peak and determination of running speeds the participants completed three 10-minute treadmill familiarisation runs on 3 separate days before the vo2 peak testing. the standard bruce protocol was employed to determine vo2 peak oxygen consumption that was measured by breath-by-breath indirect calorimetry. this was recorded using a cosmed quark b 2 metabolic cart (cosmed srl, italy). ratings of perceived exertion (rpe) were recorded every 3 minutes and heart rate was recorded every minute using a polar heart rate monitor. the test was considered to be maximal if the participants exhibited two or more of the following: rpe ≥19; respiratory exchange ratio ≥1.1; heart rate within 5 beats.min -1 of theoretical maximum heart rate (220 age). using metabolic equations 16 a speed was calculated that would elicit 75% of the participants’ vo2 peak on a horizontal surface. this would be the speed that the participants ran during the downhill run. therefore, each participant ran at the same relative intensity. downhill run the downhill run was performed 2 weeks after the vo2 peak test. participants were instructed to ingest a normal mixed diet, to be well hydrated, and to refrain from any strenuous exercise for at least 72 hours before the downhill run. the downhill runs were performed in a randomised order, between 05h00 and 11h00 over 2 consecutive saturdays. this ensured that not all the members of each group were tested on the same saturday. the participants ran in a fasted state (at least 8 hours after final meal). at the start of the run, they warmed up for 5 minutes by running on a level grade at the predetermined speed. the treadmill was then lowered to a -13.5% level and participants ran for 60 minutes. they remained in the exercise testing laboratory for 12 hours after the run, and were provided with food and fluid and encouraged to eat and drink water ad libitum. biological fluid sampling and processing on arriving in the exercise teaching laboratory, participants were required to sit quietly for 10 minutes before the run. a qualified phlebotomist then inserted a venous catheter (22 gauge, 2.2 cm), which was kept patent using a diluted heparin/saline solution. a 15 ml blood sample, using 2 vacutainer draw tubes (5 ml edta for ck and 10 ml serum separator tubes (sst) for immunoglobulin and complement), was drawn at the following times: before, immediately after (ipe) and 48 sajsm vol 21 no. 2 2009 table i. physical characteristics of the participants (mean ± sem) variable white (n=8) black (n=7) significance age (yr) 20±0.14 22±0.36 p=0.12 height (cm) 179±0.7 173±0.8 p=0.06 weight (kg) 71±0.6 70±1.5 p=0.78 body fat (%) 16±0.3 16±0.6 p=0.31 vo2 peak (ml.kg -1 .min -1 ) 44.4±0.4 43.4±0.4 p=0.50 at 3, 6, 9 and 12 hours after the run. subjects were also required to return for further blood draws at 24, 48 and 72 hours after the run. at these times a standard antecubital venepuncture was performed, with the same 15 ml blood sample being obtained. serum was obtained by allowing the serum separator tubes to stand at room temperature for 30 minutes, and then spun down for 10 minutes at 2 000 g. aliquots were frozen at -80°c in 0.5 ml eppendorf tubes. assessment of biological fluids creatine kinase ck activity was determined using a refletron blood analyser, which uses a colorometric assay procedure (boehringer mannheim gmbh, germany). the within-series precision (cv) of the refletron ranges from 1.8% to 3.0%, while the day-to-day precision ranges from 2.2% to 3.0%. edta blood (32 μl) was pipetted onto a refletron ck strip (roche diagnostics, indianapolis, usa). the strip was inserted into the refletron analyser for 30 seconds. printed results were recorded. if values were >1 500 iu/l the sample was diluted with equal parts distilled water (as per manufacturer instructions); 32 μl of this mixture was then pipetted onto a strip and re-run immediately. values of diluted blood were then doubled. serum complement and immunoglobulin the total serum concentration of c1-esterase inhibitor (c1-inh), c3, c4, iga, total igg and igg subclasses was quantified using laser nephelometry (behring diagnostics, frankfurt, germany). each set of blood specimens from an individual participant (9 samples) was assayed in a single run with a single lot number of reagents and consumables, by a single operator. all samples were analysed in triplicate with the interand intra-assay coefficients of variation lower than 1.9% and 2%, respectively. statistical analysis data were analysed using spss version 15.0 (spss inc., chicago, illinois, usa). a p-value <0.05 was considered as statistically significant and data are expressed as mean ± sem. physical characteristics were compared between the two groups using t-tests. a repeated measures analysis of variance was used to analyse the main effects (ethnic group and time) and the interaction effects (differences between blacks and whites at any time point(s)), for all dependent measures. the bonferroni post hoc test was used to locate the differences between means when the observed f-ratio was statistically significant (p<0.05). results participant characteristics table i reports the participant characteristics and the maximal exercise test results. there was good matching of the two groups with no significant differences between age, height, weight, body fat percentage or aerobic capacity. there were no reports of symptoms of upper respiratory tract infections throughout the study for both groups. serological variables all serum complement proteins and immunoglobulin concentrations run were within clinically normal reference ranges. 17 statistical results of the different proteins where there were significant differences are discussed individually below. there were no significant alterations in c1-esterase inhibitor and igg4. creatine kinase no significant difference in the absolute resting concentration was observed between the black and white groups. there was, however, a significant interaction effect (p=0.0055) after exercise, with absolute levels for the black group higher from 3 h to 72 h as determined by the bonferroni post hoc test (p<0.01). there was an ethnic group effect (p<0.0001), with the black group 98% higher (p<0.0001). the sum of values (mean ± sem) for all time points for the black and white groups was 476±64 iu/l and 240±47 iu/l, respectively. there was also a time effect with significantly (p<0.001) elevated ck levels observed for both groups (3 72 h), peaking at 12 h after exercise (black group = 693±35 iu/l; whites = 427±40 iu/l) (fig. 1). although sajsm vol 21 no. 2 2009 49 fig. 1. total creatine kinase activity for the black and white groups before and at hourly intervals after downhill running. there was a significant interaction effect (p=0.0055) with the creatine kinase in blacks higher from 3 h to 72 h. values are mean ± sem. fig. 1. total creatine kinase activity for the black and white groups before and at hourly intervals after downhill running. there was a significant interaction effect (p=0.0055), with the creatine kinase in blacks higher from 3 h to 72 h. values are mean ± sem. fig. 2. serum c3 and c4 for the black and white groups before and at hourly intervals after downhill running. there was a significant ethnic group effect for c3 (p=0.0018) and c4 (p<0.0001), with the means ± sem for the black group significantly higher than those for the white group. fig. 2. serum c3 and c4 for the black and white groups before and at hourly intervals after downhill running. there was a significant ethnic group effect for c3 (p=0.0018) and c4 (p<0.0001), with the means ± sem for the black group significantly higher than those for the white group. not significantly different, the relative increase from baseline at 12 h after exercise was 510% in the white versus 296% in the black group. complement c3 there was no difference in resting c3 concentrations between the two groups. during the 12-hour and 24-hour periods, there was a significant ethnic group effect (p=0.0018), with the mean for the black group (1.61±0.01 g/l) being approximately 17.5% higher than that for the white group (1.37±0.04 g/l). this difference could be accounted for by the decrease in c3 in whites from ipe (-7%) through to 72 h (-19%) after the downhill run compared with baseline. no significant time (p=0.9) or interaction effects (p=0.9) were observed (fig. 2). c4 there was no difference in resting c4 concentrations between the two groups. during the 12-hour and 24-hour periods, there was a significant ethnic group effect (p<0.0001), with the mean for the black group (0.37±0.01 g/l) approximately 37% higher than that for the white group (0.27±0.002 g/l). this difference could be accounted for by: (i) an increase in c4 in blacks from 6 h (+9%) to 72 h (+13%), peaking at 48 h (+26%); and (ii) a slight decrease in c4 in whites, with the lowest concentration at 12 h (-5%), after the downhill run. no significant time (p=0.9) or interaction effects (p=0.9) were observed (fig. 2). immunoglobulin total igg there was a significant difference (p<0.0001) in resting total igg concentrations between the two groups, with the baseline concentrations 21% higher for the black group compared with the white group. there was a significant ethnic group effect (p<0.0001), with the mean for the black group (14.52±0.13 g/l) approximately 29% higher than that for the white group (11.26±0.13 g/l). no significant time (p=0.9) or interaction effects (p=0.9) were observed (fig. 3). igg1 there was a significant difference (p<0.0001) in resting igg1 concentrations between the two groups, with the baseline concentrations 25% higher for the black group compared with the white group. there was a significant ethnic group effect (p<0.0001), with the mean for the black group (8.42±0.11 g/l) approximately 32% higher than that for the white group (6.39±0.07 g/l). no significant time (p=0.9) or interaction effects (p=0.9) were observed (fig. 3). igg2 there was no difference in resting igg2 concentrations between the two groups. there was a significant ethnic group effect (p=0.0079), with the mean for the black group (3.04±0.06 g/l) approximately 19% lower than that for the white group (3.62±0.06 g/l). this difference could be accounted for by: (i) a decrease in igg2 in blacks, lowest concentration at 72 h (-17%); and (ii) an increase in igg2 in whites, highest concentration at 9 h (+9%), after the downhill run. no significant time (p=0.9) or interaction effects (p=0.9) were observed (fig. 3). igg3 there was no difference in resting igg3 concentrations between the two groups. there was a significant ethnic group effect (p<0.0001), with the mean for the black group (0.53±0.02 g/l) approximately 71% higher than that for the white group (0.31±0.001 g/l). this difference could be accounted for by: (i) an increase in igg3 in blacks from ipe (+8%) to 72 h (+17%), peaking at 6 h (+29%); and (ii) a decrease in igg3 in whites from ipe (-7%) to 72 h (-11%), lowest concentration at 3 h (-14%), after the downhill run. no significant time (p=0.9) or interaction effects (p=0.9) were observed (fig. 3). iga there was no difference in resting iga concentrations between the two groups. there was a significant ethnic group effect (p<0.033), with the mean for the black group (2.02±0.01 g/l) approximately 11% higher than that for the white group (1.82±0.02 g/l). no significant time (p=0.9) or interaction effects (p=0.9) were observed (fig. 3). discussion the main finding of the study was that the black group demonstrated consistently higher absolute levels of ck after the downhill run compared with the white group. the results also suggested that there are ethnic differences in the resting and/or post-exercise levels of selected serum complement proteins and immunoglobulins. the ck result supports previous research examining racial differences in serum ck in south african males. 18 the differences in absolute ck levels may be attributed to differences in muscle fibre type/distribution and/or lean muscle mass. 18 however, the white group experienced a greater relative increase (% change 50 sajsm vol 21 no. 2 2009 pre post 3 6 9 12 24 48 72 8 10 12 14 16 18 time (h) ig g (g /l) pre post 3 6 9 12 24 48 72 4 6 8 10 12 african caucasian time (h) ig g 1 (g /l) pre post 3 6 9 12 24 48 72 2.0 2.5 3.0 3.5 4.0 4.5 5.0 time (h) ig g 2 (g /l) pre post 3 6 9 12 24 48 72 0.0 0.2 0.4 0.6 0.8 time (h) ig g 3 (g /l) pre post 3 6 9 12 24 48 72 1.4 1.6 1.8 2.0 2.2 2.4 time (h) ig a (g /l) fig. 3. serum total igg, igg1, igg2, igg3 and iga for the black and white groups before and at hourly intervals after downhill running. there was a significant ethnic group effect, with the means ± sem for the black group significantly higher than those for the white group for total igg (p<0.0001), igg1 (p<0.0001), igg3 (p<0.0001) and iga (p<0.033), while the white group had higher igg2 levels (p=0.0079). fig. 3. serum total igg, igg1, igg2, igg3 and iga for the black and white groups before and at hourly intervals after downhill running. there was a significant ethnic group effect, with the means ± sem for the black group significantly higher than those for the white group for total igg (p<0.0001), igg1 (p<0.0001), igg3 (p<0.0001) and iga (p<0.033), while the white group had higher igg2 levels (p=0.0079). from baseline) compared with the black group at 12 h after exercise. specifically, there was a 510% increase in ck in the white group compared with 296% in the black group. although this was not significantly different, it may imply that the white group experienced greater muscle damage. this group has been shown to have a lower percentage type iia fibres, 19 and type ii fibres are more susceptible to exercise-induced damage 20 and reperfusion injury. 21 based on this we would have expected to see higher relative increases in ck in the black group; however, we observed the opposite. higher resting concentrations of ck have been attributed to greater lean muscle mass although the literature is conflicting. 22 this was not measured in the current study and may partly be responsible for the differences observed. fukashiro et al. 23 have shown that black athletes have significantly greater muscle viscosity, elasticity and stiffness compared with white athletes. the ability to ‘accommodate’ greater stress may result in less muscle damage and could possibly explain the lower relative increase in the black group in the current study. numerous studies have shown that eccentrically biased exercise may result in the elevation of a number of inflammatory markers. this, and the subsequent pain experienced by the participant, has generally been attributed to muscle damage. while a number of studies have reported a significant elevation in complement proteins after exercise, 24,25 the current study failed to elicit significant changes in complement c1-inh, c3 and c4. this finding was surprising considering that: (i) the participants were untrained; and (ii) research has previously shown that a similar exercise protocol is able to elicit significant elevations in immunoglobulins 26 and chemotactic cytokines. 27 in support of our findings, research has documented that certain complement proteins and complement regulatory proteins may not be affected by prolonged strenuous exercise. 25,28,29 the inconsistent and often conflicting results observed in the literature highlight that a true understanding of the roles of complement proteins in response to exercise requires further elucidation. research performed internationally and in south africa has demonstrated racial/ethnic differences in the reference ranges for serum iga, igm, total igg and igg sub-classes. 30-34 black children and adults tend to have higher values than whites. 31-33 the results of the current study demonstrate that the black group has significantly higher circulating levels of complement proteins, c3 and c4, as well as immunoglobulin classes and subclasses, iga, igg1 and igg3. igg1 and igg3 are strong activators of the classic pathway of complement, while iga activates the alternative complement pathway. 11 igg2, a weaker activator of complement, 11 was lower in the black group compared with the white group. in addition, there was no difference in igg4, a subclass that does not activate complement. 11 the elevated complement and immunoglobulin levels suggest a heightened immune/inflammatory milieu in the circulation of black males compared with whites. further research is required to determine the factors that may be responsible for racial differences in circulating complement and immunoglobulin. previous research has suggested that increased exposure to infectious diseases, due to poorer socioeconomic conditions, may play a role in altering immune function in blacks. 30,33,34 increased exposure to infectious disease may enhance innate and adaptive immune function, resulting in constitutively higher complement and immunoglobulin levels. however, genetic differences may also be a factor and, together with socio-economic conditions, could shape the development and maturation of innate and adaptive immunity in the black group. conclusion the white group showed a greater relative increase in ck activity compared with the black group. although speculative, this may imply that whites are more prone to muscle damage, the effect of which may have implications with regard to how these groups train and adapt to training. the altered complement and immunoglobulin levels in the black group suggest a heightened immune/inflammatory milieu in the circulation. further research is required to determine the underlying factors responsible for this finding as well as the possible performance and health implications. references 1. kohn ta, essén-gustavsson b, myburgh kh. do skeletal muscle phenotypic characteristics of xhosa and caucasian endurance runners differ when matched for training and racing distances? j appl physiol 2007;103:932-940. 2. burchard eg, ziv e, coyle n, et al. the importance of race and ethnic background in biomedical research and clinical practice. n engl j med 2003;348:1170-1175. 3. miller ma, cappuccio fp. ethnicity and inflammatory pathways -implications for vascular disease, vascular risk and therapeutic intervention. curr med chem 2007;14:1409-1425. 4. zabaleta j, schneider bg, ryckman k, et al. ethnic differences in cytokine gene polymorphisms: potential implications for cancer development. cancer immunol immunother 2008;57:107-114. 5. gleeson m. immune system adaptation in elite athletes. curr opin clin nutr metab care 2006;9:659-665. 6. fridén j, sjöström m, ekblom b. myofibrillar damage following intense eccentric exercise in man. int j sports med 1983;4:170-176. 7. jeukendrup ae, vet-joop k, sturk a, et al. relationship between gastrointestinal complaints and endotoxaemia, cytokine release and the acutephase reaction during and after a long-distance triathlon in highly trained men. clin sci 2000; 98:47-55. 8. malm c, sjödin tl, sjöberg b, et al. leukocytes, cytokines, growth factors and hormones in human skeletal muscle and blood after uphill or downhill running. j physiol 2004;556:983-1000. 9. moldoveanu ai, shephard rj, shek pn. exercise elevates plasma levels but not gene expression of il-1beta, il-6, and tnf-alpha in blood mononuclear cells. j appl physiol 2000;89:1499-1504. 10. janeway ca, travers p, walport m, shlomchik m. immunobiology. the immune system in health and disease. new york: garland publishing, 2001. 11. roitt i, brostoff j, male d. immunology. edinburgh: elsevier science limited, 2001. 12. rus h, cudrici c, niculescu f. the role of the complement system in innate immunity. immunol res 2005;33:103-112. 13. heyward vh, stolarczyk lm. applied body composition assessment. champaign, il.: human kinetics, 1996. 14. barrett b, brown rl, mundt mp, et al. the wisconsin upper respiratory symptom survey is responsive, reliable, and valid. j clin epidemiol 2005; 58:609-617. 15. ross wd, wilson nc. growth and development. a stratagem for proportional growth assessment. acta paediatrica belgia 1974;24:169-182. 16. balady gj, berra ka, golding la, et al. acsm’s guidelines for exercise testing and prescription. baltimore: lippincott williams & wilkins, 2000. 17. mckune aj, smith ll, semple sj, et al. changes in mucosal and humoral atopic-related markers and immunoglobulins in elite cyclists participating in the vuelta a espana. int j sports med 2006;27:560-566. 18. gledhill rf, van der merwe ca, greyling m, van niekerk mm. race-gender differences in serum creatine kinase activity: a study among south africans. j neurol neurosurg psychiatry 1988;51:301-304. 19. ama pf, simoneau ja, boulay mr, serresse o, thériault g, bouchard c. skeletal muscle characteristics in sedentary black and caucasian males. j appl physiol 1986;61:1758-1761. 20. byrne c, twist c, eston r. neuromuscular function after exercise-induced muscle damage: theoretical and applied implications. sports med 2004;34:49-69. sajsm vol 21 no. 2 2009 51 21. chan rk, austen wgj, ibrahim s, et al. reperfusion injury to skeletal muscle affects primarily type ii muscle fibers. j surg res 2004;122:5460. 22. brancaccio p, maffulli n, limongelli fm. creatine kinase monitoring in sport medicine. br med bull 2007;81-82:209-230. 23. fukashiro s, abe t, shibayama a, brechue wf. comparison of viscoelastic characteristics in triceps surae between black and white athletes. acta physiol scand 2002;175:183-187. 24. dufaux b, order u. complement activation after prolonged exercise. clin chim acta 1989;13:45-49. 25. semple sj, smith ll, mckune aj, et al. serum concentrations of c reactive protein, alpha1 antitrypsin, and complement (c3, c4, c1 esterase inhibitor) before and during the vuelta a españa. br j sports med 2006;40:124-127. 26. mckune aj, smith ll, semple sj, mokethwa b, wadee aa. immunoglobulin responses to a repeated bout of downhill running. br j sports med 2006;40:844-849. 27. smith ll, mckune aj, semple sj, sibanda e, steel h, anderson r. changes in serum cytokines after repeated bouts of downhill running. appl physiol nutr metab 2007;32:233-240. 28. fallon ke. the acute phase response and exercise: the ultramarathon as prototype exercise. clin j sport med 2001;11:38-43. 29. simpson rj, florida-james gd, whyte gp, et al. the effects of marathon running on expression of the complement regulatory proteins cd55 (daf) and cd59 (macif) on red blood cells. eur j appl physiol 2007;99:201-204. 30. milner lv, calitz f. serum immunoglobulin levels in white, asiatic and bantu blood donors. s afr med j 1971;45:683-685. 31. pieters h, brand ce, badenhorst pn, hendricks ml. immunoglobulin g sub-class concentrations in south african adults: ethnic differences and reference ranges. br j biomed sci 1997;54:104-109. 32. ritchie rf, palomaki ge, neveux lm, navolotskaia o. reference distributions for immunoglobulins a, g, and m: a comparison of a large cohort to the world’s literature. j clin lab anal 1998;12:371-377. 33. roode h. serum immunoglobulin values in white and black south african pre-school children. part i: healthy children. j trop pediatr 1980;26:104107. 34. shulman g, gilich gc, andrew mj. serum immunoglobulins g, a and m in white and black adults on the witwatersrand. s afr med j 1975;49:11601164. 52 sajsm vol 21 no. 2 2009 all manuscripts should be submitted online: www.sajsm.org.za. if this is not feasible, the manuscript may be submitted, via e-mail, as a microsoft word attachment, to mike lambert, editor-in-chief, at mike.lambert@uct.ac.za. copyright material submitted for publication in the south african journal of sports medicine (sajsm) is accepted provided it has not been published elsewhere. copyright forms will be sent with acknowledgement of receipt and the sajsm reserves copyright of the material published. the sajsm does not hold itself responsible for statements made by the authors. authorship authorship should be based only on substantial contribution to: (i) conception, design, analysis and interpretation of data; (ii) drafting the article 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’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´’´ sajsm vol 19 no. 4 2007 the reported results. all data should be presented with appropriate indicators of measurement error or uncertainty (such as standard deviations or confidence intervals). avoid sole reliance on statistical hypothesis testing, such as the use of p values, which fails to convey important quantitative information. precise p values must be shown as indirect indications such as p>0.05 or p=ns are unacceptable and difficult for other researchers undertaking meta-analyses. 8. abbreviations should be spelt out when first used in the text and thereafter used consistently. scientific measurements should be expressed in si units. 9. present your results in a logical sequence in the text, tables, and figures. do not repeat the presentation of data in the text, tables or figures. tables and figures should appear on separate pages. do not discuss data in this section. data should be presented so that the number of digits and decimals are scientifically relevant. 10. in the discussion section emphasise the new and important aspects of the study and the conclusions that follow from them. do not repeat in detail data or other material given in the introduction or the results section. include in the discussion section the implications of the findings and their limitations, including implications for future research. relate the observations to other relevant studies. link the conclusions with the goals of the study but avoid unqualified statements and conclusions not completely supported by your data. wherever possible comment on the practical applications of the study. references references should be inserted in the text as superior numbers, with the first reference being #1 and the next reference #2 etc. the references should be listed at the end of the article in numerical order (i.e. in order of appearance). authors are responsible for verification of references from the original sources. references should be set out in the vancouver style and approved abbreviations of journal titles used; consult the list of journals in index medicus for these details. names and initials of all authors should be given unless there are more than six, in which case the first three names should be given followed by et al. first and last page numbers should be given. journal references should appear thus: 1. reilly t, edwards b. altered sleep-wake cycles and physical performance in athletes. physiol behav 2007;90(2):274-284. 2. lane kn, wenger ha. effect of selected recovery conditions on performance of repeated bouts of intermittent cycling separated by 24 hours. j strength cond res 2004;18(4):855-860. 3. borg g. perceived exertion as an indicator of somatic stress. scand j rehabil med 1970;2(2):92-98. book references should be set out as follows: 1. jeffcoate n. principles of gynaecology. 4th ed. london: butterworth; 1975. p. 96-101. 2. weinstein l, swartz mn. pathogenic properties of invading microorganisms. in: sodeman wa jun, sodeman wa, eds. pathologic physiology: mechanisms of disease. philadelphia: wb saunders; 1974. p. 457-472. manuscripts accepted but not yet published can be included as references followed by (in press). unpublished observations and personal communications may be cited in the text, but not in the reference list. cover letter all submissions must be accompanied by a cover letter including the following information: 1. this manuscript has been read and approved by all the listed coauthors and meets the requirements of co-authorship as specified above. 2. a declaration that the manuscript is not under review with any other journal and has not been published previously. 3. a statement that prior written permission has been obtained for reproduction of previously published material (where appropriate). 4. a statement detailing any potential conflicts of interest (where appropriate). galley proofs galley proofs will be forwarded to the author before publication. please note that alterations to typeset articles are time-consuming and need to be kept to a minimum. change of address please notify the editorial department of any address changes so that proofs and invoices may be mailed without delay. cpd points authors can earn up to 15 cpd points for published articles. certificates will be provided on request after the article has been published. 32 sajsm vol 21 no. 1 2009 sajsm vol 23 no. 1 2011 31 if… a tendon parody by jon patricios (with apologies to rudyard kipling, jill cook & hakan alfredson) if you can get your head around a tendon that wears and tears and hurts when it’s a bendin’ if you can trust yourself to make achilles new but make allowance for frustration too; if you can wait but not be idle waiting, but teach and guide and empathise, don’t mind being hated, or cry anticipating, at times not look too good nor seem too wise: if you can dream of healing that is faster, but know that symptoms too will wax and wane; accept the days of triumph and disaster and understand each course may just not be the same; if you can bear to hear the moans being spoken by athletes often keen to break the rules, and picture collagen that has been broken but slowly mends again with all your tools: if you don’t hinge your hopes on single fixes nor risk it all on just one consultation (they’ll leave and seek some other weird elixirs and worse – not pay you any consolation!) if you can diagnose then educate that injuries evolve over a time, you’ll start a path to which you both relate of organising collagen in line. if you can learn from cook the art of loading and hear from alfredson how to inject, incorporate some shock waves ‘spite the loathing, the ‘opathy may still be conquered yet! if you can front this unforgiving tissue with load that challenges but is still fun, they’ll rehab well and not make cost an issue and – which is more – your athlete will then run! case report 1 sajsm vol. 30 no. 1 2018 sacroiliac tuberculosis masquerading as mechanical lower back pain in a collegiate basketball athlete: a case presentation m moyaert,1,3,4 md, m med (sports med); j t viljoen,1, 2, 3 bsc (physio), mphil (exercise sci); p l viviers,1, 2, 3 mbchb, m med sc, msc (sports med), facsm; w derman,1, 2 mbchb, bsc (med) (hon), phd, ffims; r de villiers,5 mbchb; mmed (rad. d) 1 institute of sport and exercise medicine, division of orthopaedics, faculty of medicine and health sciences, stellenbosch university, south africa 2 ioc research centre, cape town, south africa 3 campus health service, stellenbosch university, south africa 4 catholic university of leuven, department of physical medicine and rehabilitation, leuven, belgium 5 winelands radiology, institute of orthopaedics and rheumatology, stellenbosch, south africa corresponding author: p l viviers (plviviers@sun.ac.za) tuberculosis (tb) is a major cause of death worldwide. in sub-saharan africa, the disease burden is especially high with south africa being one of the top seven global countries with the highest estimated numbers of tb cases (454 000 per year).[1] skeletal tb accounts for 10% of the extrapulmonary manifestations, of which only 5-8% affect the sacroiliac joint.[2] diagnosis of sacroiliac tb often proves challenging due to its insidious onset, non-specific clinical picture and low index of suspicion.[3] the most frequently reported clinical symptoms include persistent lower back pain and antalgic gait, [2-6] while several authors also report a positive straight leg raise test.[3, 4] this is likely due to the close anatomical relationship between the sacroiliac (si) joint , hip, lumbosacral plexus and the intrapelvic space. despite previous efforts to describe the symptomology and clinical presentation of sacroiliac tb, no specific mention is given to its manifestation in athletes.[3-5] this requires further elucidation, particularly as a consequence of misdiagnosis or a delay in initiation of treatment when eventual complications, such as sacroiliac joint destruction, formation of a local abscess, vertebral collapse or neurological fallout, may arise.[3, 5] all of these are potentially detrimental to the athlete’s general health, well-being and performance. case report a 21-year-old male collegiate basketball player of subsaharan african origin presented to the sports injury clinic at stellenbosch university with a four week history of spontaneous onset, progressive right-sided lumbosacral pain and stiffness. no history of trauma or any other inciting event was reported. further medical history was unremarkable, except for episodes of intermittent fatigue experienced over the past three years, related to a previously diagnosed chronic iron deficiency anaemia. at the time of this evaluation, an extensive laboratory blood workup, including a full blood count, platelet count, measures of erythrocyte sedimentation rate, as well as c-reactive protein and ferritin concentrations, were conducted. these tests revealed low ferritin concentrations, mean corpuscular volume and red cell haemoglobin concentrations. treatment ensued consisting of iron (ferrous sulphate) and multivitamin supplementation; however, poor compliance and failure to return for follow-up assessments hindered resolution of this patient’s problem. physical examination revealed palpation tenderness of the right si joint. the faber test of the right hip, straight leg raise test and gaenslen’s test were positive. in comparison, the left side was normal. no neurological abnormalities could be found related to either the lumbar spine or lower extremities. plain radiographs of the pelvis were reported as normal. a provisional diagnosis of mechanical sacroiliac joint dysfunction was made and anti-inflammatory medication was prescribed for pain relief. the patient was referred for physiotherapy treatment (including soft tissue mobilisation, hip stability exercises, dry needling and other supportive modalities). due to a poor response to conservative treatment and a background: sacroiliac tuberculosis is a rare condition for which early diagnosis and effective management frequently proves challenging. this report describes a case that was initially overlooked due to its presentation and unreported constitutional symptoms. aim: to alert clinicians about skeletal tuberculosis, an often neglected diagnostic differential, which requires a high index of clinical suspicion, especially for patients from endemic areas. findings: this patient’s presentation (sports injury) and unreported constitutional symptoms resulted in a delay in the diagnosis and initial institution of treatment. implications: this report illustrates the importance of specifically asking about constitutional symptoms, even in sports injury settings and being mindful of infectious diseases or other chronic medical conditions, which may masquerade as common sports injuries. keywords: skeletal tuberculosis, sacroiliitis, hip pain s afr j sports med 2018; 30:1-3. doi: 10.17159/2078-516x/2018/v30i1a4372 mailto:plviviers@sun.ac.za http://dx.doi.org/10.17159/2078-516x/2018/v30i1a4372 case report sajsm vol. 30 no. 1 2018 2 noticeable deterioration in his gait pattern, the patient was reassessed after eight weeks. at the time, a retrospect enquiry revealed further constitutional symptoms, which were not mentioned in the initial history, including weight loss (from 61 kg to 54 kg over a period of two months), intermittent night sweating, fatigue and a transient cough. further investigations were deemed necessary, including blood laboratory tests, which showed elevated crp (c reactive protein) concentrations of 123.8 mg/l (normal reference < 5.0 mg/l), an increased esr (erythrocyte sedimentation rate) of 75 mm/hr (normal reference 2−28 mm/hr) and a blood count within the normal range. tests for the presence of human leukocyte antigen (hla-b27) and human immunodeficiency virus (hiv) were also performed to exclude other possible causes, such as immune-mediated diseases. however, these proved to be negative. magnetic resonance imaging (mri) and computed tomography (ct) of the pelvis revealed an effusion of the right si joint with extensive oedema in the bone marrow and adjacent muscles (figs. 1a and b). these images were highly suggestive of right-sided sacroiliitis with features of an infective process. at this point, an additional differential diagnosis of tuberculosis (tb) was considered as the patient originates from a tb endemic region in sub-saharan africa and had frequent contact with a relative who had tb. diagnosis was later confirmed using a needle core biopsy of the sacrum, together with subsequent pcr (polymerase chain reaction) analysis, which was positive for mycobacterium tuberculosis (genexpert pcr). sensitivity for rifampicin was established and multidrug resistance was excluded. the patient was initiated on a four-drug combination therapy (isoniazid, rifampicin, pyrazinamide and ethambutol) with additional vitamin b6 (pyridoxine) supplementation for a minimum duration of 9-12 months. continuous monitoring of the patient consisted of clinical re-evaluation supported by standard radiographs and serial esr/crp counts every six weeks for the first three months and then every three months for the duration of the treatment. after receiving almost four months of anti-tuberculosis treatment, the patient showed a good clinical response. follow-up blood counts revealed a reduction in esr (75 mm/hr vs. 2 mm/hr) and crp (123.8mg/l vs. 3.1 mg/l), while radiography showed no progression compared to previous findings. the patient has since commenced a physical rehabilitation programme that includes progressive strengthening and aerobic conditioning. discussion in this case, the patient’s initial presentation with a “sports injury” and unreported constitutional symptoms resulted in a differential diagnosis, including sciatica, gluteal muscle strain and infectious/inflammatory disorders of the si joint. this led to a final working diagnosis of sacroilitis, followed by referral for appropriate physiotherapy treatment. however, the patient’s failure to respond to the prescribed treatment alerted the authors to the possibility of a missed diagnosis. consequently, a repeat clinical assessment, including an indepth history taking, physical examination and special tests, resulted in the identification of underlying sacroiliac tb. this demonstrates the importance of an accurate clinical assessment in order to identify underlying chronic disease in the presence of a sports injury. furthermore, a high index of clinical suspicion should be maintained for chronic medical conditions as this can influence the initial differential as well as the final working diagnosis. plain radiography (x-ray) is one of the various screening methods used to assist clinicians with an effective diagnosis of musculoskeletal tb. in this case, subtle features suggestive of joint pathology were indeed visible retrospectively on initial standard anterior posterior (ap) radiographs of the pelvis; however, these were not recognised at the time. subsequent mri and ct confirmed features of sacroilitis stemming from an infective origin. together with the history of constitutional fig.1a. mri of pelvis: t1-fat saturation post-contrast. enhancing si-joint with bone marrow oedema of the sacrum and right iliac bone. si joint fluid collection with anterior extension deep to right iliacus muscle. features compatible with an infective sacroiliitis. fig.1b. coronal ct of pelvis showing widening of the right si joint with erosion and sclerosis of the right ilium. normal left si joint. case report 3 sajsm vol. 30 no. 1 2018 symptoms for tb further investigation was warranted using specific blood markers and core needle biopsy. it is important to note that exclusive diagnosis of tb is typically demonstrated by either acid-fast bacilli (afb) on microscopy, growth of bacilli in a lowestein-jensen culture or identification of granulomatous lesions in the histologic specimen from an open biopsy or fine needle aspiration.[4,6] considering that the traditional techniques using cultures can be time-consuming, two polymerase chain reaction methods are frequently used, namely the line probe assay (lpa) method or the genexpert pcr (gxp) method. the latter method was used to confirm diagnosis of sacroiliac tb in this case. conclusion this case demonstrates important messages for the clinician working in sport and exercise medicine. firstly, chronic medical conditions can masquerade as common sports injuries, and conversely, exercise or sport may often reveal the chronic illness. it is therefore important that the clinician takes a meticulous medical history and is mindful of a wide differential during an assessment of common sports injuries, particularly when no trauma or inciting event is involved. the second important lesson is that patients should be completely reassessed should they not respond as anticipated or according to the treatment plan set out for the particular patient. patient consent: we would like to thank the patient for his consent to publish his clinical information. study funding and conflict of interest: the authors report no funding or conflict of interest. references 1. global tuberculosis report 2017. geneva: world health organization. http://www.who.int/tb/publications/global_report/en/ 2. peto hm, pratt rh, harrington ta, et al. epidemiology of extrapulmonary tuberculosis in the united states, 1993–2006. clin infect dis 2009;49(9):1350-1357.[doi:10.1086/605559] 3. prakash j. sacroiliac tuberculosis a neglected differential in refractory low back pain our series of 35 patients. j clin orthop trauma 2014;5(3):146-153. [doi:10.1016/j.jcot.2014.07.008] 4. gao f, kong xh, tong xy, et al. tuberculous sacroiliitis: a study of the diagnosis, therapy and medium-term results of 15 cases. j int med res 2011;39(1):321-335. [doi:10.1177/147323001103900135] 5. gelal f, sabah d, doǧan r, et al. multifocal skeletal tuberculosis involving the lumbar spine and a sacroiliac joint: mr imaging findings. diagn interv radiol 2006;12(3):139-141. [pmid: 16972219] 6. patwardhan sa, joshi s. laboratory diagnosis of spinal tuberculosis: past and present. argospine news j 2011;23(3):120-124.[doi:10.1007/s12240-011-0023-9] http://www.who.int/tb/publications/global_report/en/ book review sajsm vol. 24 no. 4 2012 131 i have always had an interest in endurance sports and have been fortunate enough to work with endurance athletes while completing my phd. professor mujika is a well-respected scientist who, apart from his research work, consults with many elite endurance athletes. i was surprised at how excited i was to review a ‘textbook’. professor mujika has assembled an ‘all-star’ cast of contributors world-wide, many of whom are well-known experts in their respective fields. the book certainly did not disappoint, with all the chapters containing summaries of current and up-to-date literature from leaders in their areas of research. many of the chapters are authored in part by the ‘usual suspects’ of exercise physiology, but we are also introduced to a few new experts, who will surely become as well known as their co-authors. the clever organisation of the chapters helps with the flow of the book. the first chapter clearly outlines the requirements for endurance performance and sets the scene for the remaining chapters. the following ten chapters (two to eleven) offer the reader practical information on how to optimise endurance performance. these ten chapters include topics of periodisation, quantifying training load, high-intensity training, recovery strategies and tapering. i especially enjoyed the chapters on high-intensity training by paul laursen, quantifying training load by mike lambert, and recovery by shona halson and christos argus. this may be because these chapters are closely aligned to my research, but i found them to be well written and practical. each chapter ends with a summary of the key points covered and contains a full reference list. the following six chapters cover the physiological responses to endurance training in more detail. the topics covered include: cardiovascular and metabolic adaptations to endurance training, adaptations of skeletal muscle, and hormonal responses to endurance training. these chapters take the reader a little deeper into the physiology of endurance performance on the molecular and cellular level. coaches should not be put off by this, as the work is well written and presented in a logical manner. these chapters are essential to the understanding of an athlete’s response to endurance training. chapter 18 covers physiological testing and adaptation to endurance training. it was great to read a chapter on this topic that didn’t put all the eggs in the vo2max basket. drs pyne and saunders emphasise the importance of economy of movement, fat utilisation (glycogen sparing) and peak power output or peak treadmill running speed as important factors related to endurance performance. the authors offer options for both laboratory and field testing as well as maximal and sub-maximal testing. physiological testing is an important tool for endurance athletes and coaches and assists in the monitoring of training adaptation, training intensity prescription and profiling athletes for specific events. as a coach myself, i am often asked nutrition-related questions by the athletes i work with. i am an exercise physiologist and coach, sadly not a dietician, and as a result i can’t prescribe eating plans or dietary interventions to my athletes. i am sure that there are many endurance coaches in south africa or all over the world who face the same dilemma. fortunately, chapter 21 covers nutritional strategies for endurance training and competition. the authors of the chapter, louise burke and gregory cox, have put all the key points into three easy-to-digest (pun intended) tables, which allow the reader to get an idea of fuelling strategies for exercise and recovery. while this information may not equip the reader with enough knowledge or experience to prescribe a diet or dietary intervention, it should allow you to determine if your athletes are adopting good nutritional habits. the book also contains five chapters on endurance training and competition in challenging environments, including heat, cold, altitude, areas of high pollution and the effects of longdistance travel. most athletes will be exposed to one or more of these environmental conditions while training or competing and a coach or physiologist equipped with the knowledge on how to handle these environments will be an asset to any athlete. once again, the physiological effects of these environments on performance are discussed, as well as strategies to maximise performance in these conditions. the book is expensive, but i would certainly recommend it to coaches with some background in physiology and any lecturers who may run an undergraduate coaching course. the book covers all the bases of endurance performance that will serve the reader well. benoit capostagno phd programme uct/mrc research unit for exercise science and sports medicine endurance training science and practice edited by iñigo mujika. pp. 328. donostia. 2012. €151.30. isbn 978-84-939970-0-7. km_c227-20180711130409 38 sajsm vol. 25 no. 2 2013 editorial injury management programme at sa rugby youth tournaments as this edition of the journal goes to press, the annual rugby youth tournaments begin around the country. these national tournaments provide an opportunity for the best young rugby players in the country to showcase their skills. in addition to catering for players of the under-13, -16 and -18 age groups, there is also a tournament for players from schools with special needs. the tournaments provide an opportunity for talent scouts representing schools, provinces and rugby academies to examine the skills of the players and offer contracts to those who they consider to be special. rugby is a sport involving collisions between players, and sometimes, when they are sprinting at maximum speed, injuries are inevitable. it is for this reason that the medical division of sa rugby and boksmart[1] initiated a programme to attempt to make the game safer. they have provided medical facilities at each tournament venue, and for the last 3 years, have had staff to record every injury treated by the doctor at each tournament. the information about each injury is entered into a database and analysed.[2] the information includes the type of injury, body part injured, mechanism of injury, stage and phase of the game when the injury occurred. the field conditions are also noted. parents of injured players are contacted regularly after the tournament, until the injury has repaired. the aim is to quantify the severity of the injuries and medical services required for each tournament. this information will also support a project that is currently underway to calculate the financial cost of each injury. by providing accurate information to the actuaries of medical insurance companies, it will be possible to calculate an insurance package specifically designed for the tournament. this is particularly relevant as nearly a quarter of the players attending the tournaments do not have medical aid to cover their expenses in the event of an injury. also, at two tournaments (under-18 academy week and club championships) the players are requested to complete a questionnaire probing their knowledge, attitude and behaviour regarding injuries. this serves to identify key areas that need to be addressed and tracks changes in knowledge, attitude and behaviour from year to year. this shows that sa rugby is aspiring to principles of ‘best practice’ in trying to manage the game efficiently from an injury perspective. by implementing a sophisticated data-collection programme, the organisation is able to measure the problem of injuries in its youth players and consequently position itself to manage these injuries. this means that medical services at each tournament can be planned more accurately, and the organisation is well-positioned to detect any trends in injuries that may emerge as a result of rule changes. the programme that sa rugby has put in place is not ‘rocket science’; it has merely been implemented in a systematic way using measurement tools devised though a process of international consensus.[3] emphasis has been placed on collecting data in a methodical way, and data analysis is an ongoing process. there is no reason why the other sporting codes cannot implement similar programmes. consensus documents describing definitions of injuries and methodological recommendations for cricket[4] and soccer[5] have been published; therefore, the next step requires a decision by management to measure and analyse the data for these sports. when all major sports have embraced this approach, there is a strong possibility that they will become safer for their participants. when participants see that the administrators are ‘upping their game’, there is a very good chance that they will respond with superior playing performances. the articles in this edition of the journal cover a broad scope, ranging from the effects of exercise on mood in breast cancer patients,[6] to the risk of cardiac arrest in young athletes.[7] there are also two articles on injuries associated with long-distance running,[8,9] an article on the fitness of women rugby players[10] and, finally, a study on the effects of over-the-counter dosages of pseudoephedrine on swim ming performance. [11] enjoy the read! mike lambert editor-in-chief 1. viljoen w, patricios j. boksmart – implementing a national rugby safety programme. br j sports med 2012 may 19;46(10):692-693. [http://dx.doi.org/10.7196/sajsm.460] 2. brown j, verhagen e, viljoen w, et al. the incidence and severity of injuries at the 2011 south african rugby union (saru) youth week tournaments. south african journal of sports medicine 2012;24(2):49-54. 3. fuller cw, molloy mg, bagate c, et al. consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union. br j sports med 2007;41(5):328-331. [http://dx.doi.org/10.1136/bjsm.2006.033282] 4. orchard j, newman d, stretch r, frost w, mansingh a, leipus a. methods for injury surveillance in international cricket. journal of science and medicine in sport 2005;8(1):1-14. [http://dx.doi.org/10.1016/s1440-2440(05)80019-2] 5. junge a, dvorak j. influence of definition and data collection on the incidence of injuries in football. am j sports med 2000;28(5 suppl):s40-46. 6. van oers hm. exercise effects on mood in breast cancer patients. south african journal of sports medicine 2013;25(2):55-59. [http://dx.doi.org/10.7196/sajsm.481] 7. gradidge pj-l, constantinou d, goldberg l. sudden cardiac arrest risk in young athletes. south african journal of sports medicine 2013;25(2):53-54. [http://dx.doi. org/10.7196/sajsm.469] 8. ellapen tj, satyendra s, morris j, van heerden hj. common musculoskeletal injuries among recreational half-marathon runners in kwazulu-natal. south african journal of sports medicine 2013;25(2):39-43. [http://dx.doi.org/10.7196/sajsm.360] 9. kellogg ds, joslin j. the legend of plantar neuropraxia in long-distance athletes. south african journal of sports medicine 2013;25(2):51-52. [http://dx.doi.org/10.7196/ sajsm.468] 10. hene nm, bassett sh. changes in the physical fitness of elite women’s rugby union players over a competitive season. south african journal of sports medicine 2013;25(2):47-50. [http://dx.doi.org/10.7196/sajsm.371] 11. gradidge pj-l, constantinou d, heard s-m, king c, morris-eyton h. effect of a therapeutic dose of pseudoephedrine on swimmers’ performance. south african journal of sports medicine 2013;25(2):43-36. [http://dx.doi.org/10.7196/sajsm.378] s afr j sm 2013;25(2):38. doi:10.7196/sajsm.493 http://dx.doi.org/10.7196/sajsm.460] http://dx.doi.org/10.1136/bjsm.2006.033282] http://dx.doi.org/10.1016/s1440-2440 http://dx.doi.org/10.7196/sajsm.481] http://dx.doi.org/10.7196/sajsm.469] http://dx.doi.org/10.7196/sajsm.469] http://dx.doi.org/10.7196/sajsm.360] http://dx.doi.org/10.7196/sajsm.468] http://dx.doi.org/10.7196/sajsm.468] http://dx.doi.org/10.7196/sajsm.371] http://dx.doi.org/10.7196/sajsm.378] editorial 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license the state of the south african journal of sports medicine, 2019 this is the second year of the new format of the south african journal of sports medicine. when we made the change in 2017 we were confident it was going to have a positive impact on the quality of the journal [1]. the reason for making the change to a one-issue-per-year format was primarily to speed up the time from accepting a paper to the time of publication. we reported last year that this time was reduced to about three weeks [2]. we received positive feedback from authors and can now report this duration has been reduced to two weeks in most cases. we use the open journal system (ojs) as the journal management system for the south african journal of sports medicine. ojs is open source software designed for the management of peer reviewed academic journals. this was developed by the public knowledge project, a non-profit research initiative, through collaboration between the faculty of education at the university of british columbia, the canadian centre for studies in publishing at simon fraser university, the university of pittsburgh, ontario council of university libraries, the california digital library and the school of education at stanford university [3]. in 2018 the ojs was upgraded to version 3. this change improved the usability of the website for authors and reviewers. this version of the ojs also has an automated feature for exporting a citation to a reference manager. altmetric data are also readily available for each publication. the south african journal of sports medicine remains accredited by the scientific electronic library online (scielo) sa, south africa’s main open-access (free to access and free to publish) searchable full-text journal database. scielo sa is managed by the academy of science of south africa (assaf), funded by the south african department of science and technology and endorsed by the south african department of higher education and training (dhet).the scielo sa database represents 76 journals published within south africa. the south african journal of sports medicine is also on the department of higher education and training (dhet) list of accredited journals. this is important because south african authors who work at tertiary institutions and publish in the south african journal of sports medicine can get a subsidy for their paper from the dhet. a requirement for 2019 is that all authors and co-authors have to include their open researcher and contributor ids (orcid) when the manuscript is submitted. this seems to be an international trend in academic publishing and is designed to provide each author with unique identification. the orcid can easily be obtained by registering on the orcid website (http://www.orcid.org). our publishing team includes a journal manager, copyeditor and typesetter. this committed group has developed standard operating procedures which enable an efficient workflow from the submitted paper through to the published paper. it is noteworthy that this group operates within the constraints of an extremely limited annual budget. however, we do have challenges. the major challenge, which we share with all journals, is to get quality reviews of submitted manuscripts. the peer review process, a fundamental principle of science, relies on experts who can share their time to review a paper. because this is usually done anonymously, the reviewers do not get recognition. while it is always noble to make a contribution without recognition, the reality is that more experts are declining requests to review a paper. this increases the burden on editorial staff who have to spend more time trying to find a competent and willing reviewer. publons (http://www.publons.com/about/home/) have attempted to address this problem by providing an online platform where reviews are recorded. once a review is completed, the editor of the journal emails the reviewer acknowledging the submitted report. the reviewer simply forwards this email to the publons platform where the information is recorded in the reviewer’s file. the platform can generate data rich reports on the numbers of reviews, quality of journals and ranking of the researcher. this profile provides the reviewer with useful information which can be used in a job promotion or funding application. finally, a reminder that the south african journal of sports medicine is sponsored by the south african sports medicine association (sasma). therefore we are obligated fulfil the objectives of sasma and ensure that the publications are relevant to issues in south africa. mike lambert editor-in-chief s afr j sports med 2019;31:1. doi: 10.17159/2078-516x/2019/v31i1a6055 references 1. lambert mi. new format of the south african journal of sports medicine. s afr j sports med, 2017. [doi /10.17159/2078516x/2017/v29i0a2856] 2. lambert mi. the transition of the south african journal of sports medicine. s afr j sports med, 2018: 1–1. [doi.org/10.17159/2078516x/2018/v30i1a4796] 3. public knowledge project. 2019. [https://www.pkp.sfu.ca] (accessed february 13th, 2019) http://www.publons.com/about/home/ http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6055 /users/mikelambert/library/containers/com.apple.mail/data/library/mail%20downloads/b98f2d62-3a9c-429e-821d-778deb6b5331/%5bdoi.org/10.17159/2078-516x/2018/v30i1a4796 /users/mikelambert/library/containers/com.apple.mail/data/library/mail%20downloads/b98f2d62-3a9c-429e-821d-778deb6b5331/%5bdoi.org/10.17159/2078-516x/2018/v30i1a4796 https://www.pkp.sfu.ca/ https://orcid.org/0000-0001-8979-1504 sajsm 476.indd original research 104 sajsm vol. 26 no. 4 2014 background. stress is an integral part of daily living, but chronic activation of the stress response without the ability to express the physical response results in overloading of the physiological and psychological systems. objective. to decrease perceived stress by means of one known and/or one relatively unknown physical activity, namely aerobic exercise and somatic awareness exercise. methods. this investigation made use of a quantitative, comparative, experimental research design over an 8-week period using preand post-tests. participants were measured for psychological stress using a perceived stress scale. the participants were divided into those who were physically untrained and those who participated in exercise training programmes. results. there were five groups in total. the physically untrained individuals were divided into four groups: a somatic awareness exercise group (n=9); an aerobic exercise group (n=15); a combination group taking part in both somatic awareness and aerobic exercise (n=8); and a control group (n=15). the 5th group contained individuals who participated in physical exercise prior to entering the programme; they were given somatic awareness exercise (n=9) in addition to their existing physical exercises. an independent samples t-test revealed significant changes for perceived stress in the aerobic, somatic, combination and exercise groups, with a 95% confidence level in comparison with the control group. conclusion. various physical modes such as aerobic exercise, somatic awareness training and a combination of the two may be used to decrease one’s perceived stress in moderately to highly stressed individuals who are sedentary or who are physically active. s afr j sm 2014;26(4):104-108. doi:10.7196/sajsm.476 the effect of various physical exercise modes on perceived psychological stress m k magalhaes das neves,1 mphil (biokinetics); j m loots,1 dsc (physiol), dtech (agric); r l van niekerk,2 dlit et phil (psychology) 1 department of sport and movement studies, faculty of health, university of johannesburg, south africa 2 department of psychology, faculty of humanities, university of johannesburg, south africa corresponding author: r l van niekerk (leonvn@uj.ac.za) stress is an integral part of the life of every human being, and is necessary for human functioning and adaptation. if the demands of life, in modern society for example, surpass the ability to cope, one will be in distress or in a negative stressful state. in order for a situation to be deemed as negatively stressful or not, one needs to perceive or appraise one’s demands and ability to cope; this is defined as perceived stress.[1] chronic exposure to stress can be detrimental to one’s physiological and psychological functioning, and result in chronic stress-related diseases.[2,3] worldwide, people manifest stressrelated diseases, and since excessive stress has been poorly managed, there have been increases in stress levels as high as 44%.[4] in the working environment, south africans have high perceived stress levels, with the greatest prevalence of stress among whites, females and individuals in the age group 20 30 years.[5] annually, there can be as much as a r12 billion loss in south africa (sa) due to stress-related absenteeism and low work productivity, which causes huge losses in economic profits and growth.[6] it has also been found that sa individuals who have high levels of psychological stress do not partake in physical exercise, and engage in poor behavioural patterns (such as alcohol consumption, smoking and drug abuse) because of an inability to cope with the high levels of perceived stress.[7] poor behavioural patterns in conjunction with decreased physical activity levels can lead to increases in perceived stress and manifestation of chronic disease conditions, which are currently increasing rapidly in the sa population.[8] the increased prevalence of stress-related disease indicates a need for improved stress management, such as the use of the psychological technique of cognitive behavioural therapy.[9] however, physiological techniques such as yoga[9] and aerobic exercise[10] have been shown to be just as effective in decreasing perceived stress as cognitive behavioural therapy. it is important to employ a physiological technique and not only a psychological technique, because the stress response is in itself physical[2,11] and there needs to be a healthy physical outlet. although aerobic exercise is widely used to decrease perceived stress, it has also been shown to have no or little effect on perceived stress,[12] and it is for this reason that the objective of the present study is to investigate the efficacy of somatic awareness exercise techniques (a different physiological mode) on decreasing perceived stress. (for a complete literature review on stress and somatic awareness, please contact the authors.) these techniques have been found to be effective in decreasing stress because they address both psychological and physiological aspects of the individual, and holistically integrate the self.[13] somatic awareness techniques both implement and develop improved breathing, attention to the self, embodied presence, postural stability and quality of movement.[13] this is achieved by teaching correct movement patterns, increasing someone’s awareness of the acute and chronic physical manifestations of poor and correct movement patterns, and by doing so also increasing awareness of the self.[13] sajsm vol. 26 no. 4 2014 105 objective to investigate the efficacy of somatic awareness exercise on perceived stress, and to compare this with a known stress-reducing mode, namely aerobic exercise, in both trained and untrained individuals. methods participants fifty-six participants were recruited from corporate companies in the johannesburg area. the volunteers completed an informed consent form, a medical screening form and a perceived stress scale (pss). subjects were excluded from the present study if their stress levels were low (pss score <10), they were pregnant, and if they suffered from chronic illness and any absolute and relative contraindications to exercise according to the american college of sports medicine. [14] individuals who smoked were also excluded from the study, as smoking would have presented another variable that may have affected the study. the mean age of the total sample was 41 (standard deviation (sd) 11, range 22 65) years. the total sample comprised 43 (77%) females and 13 (23%) males. the ethnicity of the total sample comprised white (n=39, 69.6%), indian (n=5, 8.9%) and black (n=12, 21.4%) participants. most of the participants included in the study did not partake in regular physical exercis e. thes e untrained (s edentar y) participants were randomly assigned to either a control (n=15), an aerobic exercise (n=15), a somatic awareness (n=9) or a combination (aerobic exercise and somatic awareness) (n=8) group. some subjects who volunteered to participate in the study were physically active prior to the study, and were placed in a separate exercise group (n=9). the mean age, mean bmi, gender and ethnic distribution across the experimental and control groups are presented in table 1. both the kolmogorov-smirnov test for normality and levene’s test for homogeneity of variance were non-significant between the stress levels of the different groups, implying no statistical differences between the groups’ stress levels. no statistical differences between the age and bmi of the groups were found. research design the current investigation made use of a quantitative, comparative, experimental research design over an 8-week period, using preand post-tests. the methodological framework of the study is outlined in table 2. research instruments and method of assessment the research instrument used to measure perceived stress was the pss,[1] which has 10 items on a five-point likert scale, with scores ranging from 0 to 40. the pss was used in the pretest, which took place 1 day before commencement of the sessions, and in the posttest, which took place 1 day after the last exercise session. normative scores on the test indicate that when a participant scores <10 on the pss, they are experiencing minimal stress; a score of 10 20 indicates moderate stress, while a score of 20 30 indicates high stress and a score >30 indicates very high stress. the pss was utilised because it takes into account the degree to which a person will perceive his/her life as stressful and how much stress is present in his/her life, rather than just measuring the physical response to a specific stressor.[1] it is one of the most reliable and valid tests available for subjective stress appraisal and has a reliability score (cronbach’s alpha) of 0.72.[15] the intervention protocol prior to the intervention programme, all groups were informed that they had to participate in the study for 8 weeks, and that the required participation in the given intervention was a minimum of three times a week and a maximum of six times a week.[14] this required 24 exercise sessions over the 8-week period. the subjects were allowed to exercise at a time convenient to them, because there is no marked difference in stress levels that is dependent on the time that one exercises.[11] in the introductory sessions, all four intervention groups were shown the exercises by means of a dvd, which provided auditory and visual instructions. each group had their own dvd with set instructions and the necessary exercise protocol. the control group did not receive any of these instructions mentioned, but were asked to continue with life as usual. after the introductory sessions, the participants were not supervised, but were monitored by means of weekly phone calls and emails. participants in the intervention groups were also issued with an exercise diary to determine participant compliance, and to record their exercise sessions, duration, dates and overall mood. aerobic exercise group the aerobic exercise protocol comprised a 5 10 min aerobic warm-up at a low intensity of 5 8 on the borg scale. the warm-up was followed by any moderate aerobic exercise of 10 12 intensity on the borg scale for 20 30 min,[16] as this has been shown to contribute most to stress relief.[11] the cool-down was performed similarly to the warmup: 5 10 min at a low intensity of 5 8 on the borg scale.[16] static table 1. distribution of the age, bmi, gender and ethnicity of each group group mean age (years) mean bmi (kg/m2) gender, n ethnicity, n males females white black indian aerobic 44 30.77 7 8 3 10 2 somatic 46 30.82 1 8 9 0 0 combination 37 23.86 1 7 6 0 2 exercise 31 25.52 0 9 8 0 1 control 38 25.15 4 11 13 2 0 bmi = body mass index. 106 sajsm vol. 26 no. 4 2014 stretching was performed after cool-down, and was chosen because stretching has been shown to decrease the stress response and induce a physiological and psychological relaxation response. [10] the stretches included the stretching of gross musculature (lower back, hamstrings, neural hamstrings, quadriceps, hip flexors, trunk extensors, obliques, quadratus lumborum, groin, calves, triceps and neck) for 30 s, with each stretch repeated three times. prior to the intervention programme, the stretching instructions and guidelines[14,16] were discussed with, and demonstrated to, the participants, with emphasis on correct breathing, limb placement and range of motion. somatic awareness group the main body of work and the structure of the intervention were taken from hanna.[13] somatic awareness exercises have, as their table 2. methodological framework of the present study sample 56 participants ranked as moderately to highly stressed from the johannesburg area ages from 18 to 65 subjects met inclusion criteria pretest retrospective health questionnaires and informed consent psychological screening: stress score subjects not exercising prior to study randomly assigned into four groups exercising subjects were assigned to an exercise group intervention protocols group 1: aerobic group 2: somatic group 3: combination group 4: exercise group 5: control group warm-up: duration: 5 10 min intensity: borg scale of 5 8 warm-up: duration: 5 10 min intensity: borg scale of 5 8 warm-up: duration: 5 10 min intensity: borg scale of 5 8 warm-up: duration: 5 10 min intensity: borg scale of 5 8 no exercise exercises: type: aerobic duration: 20 30 min intensity: borg scale of 10 12 exercises: no aerobic exercise prescribed and somatic awareness exercises (lessons 1 8) exercises: type: aerobic duration: 20 30 min intensity: borg scale of 10 12 and somatic awareness exercises (lessons 1 8) exercises: continue with present exercise programme and somatic awareness exercises (lessons 1 8) cool down: duration: 5 min intensity: borg scale of 5 8 cool down: duration: 5 min intensity: borg scale of 5 8 cool down: duration: 5 min intensity: borg scale of 5 8 cool down: duration: 5 min intensity: borg scale of 5 8 post-test stress score statistics descriptive statistics one-way anova post-hoc comparisons paired sample t-test effect size anova = analysis of variance. sajsm vol. 26 no. 4 2014 107 primary goal, an increase in somatic awareness in the individual. this increased awareness is attained by teaching correct movement patterns in various parts of the body. the movements are all slow and gentle, with the emphasis on being totally aware of the proprioceptive input from each and every part of the body. this then increases the ability of participants to become aware of their own movements and posture, and make appropriate corrections where and when required. it should be noted that none of these lessons included any form of stretching. the somatic awareness training had to be done three times a week for a total of 8 weeks. the sessions were divided into eight lessons. each lesson focused on increasing awareness and releasing muscle tension in a particular group of muscles.[13] • lesson 1: extensor back muscles. this lesson focused on increasing awareness of the lower back muscles and decreasing lumbar extensor tension by increasing movement in the hips. • lesson 2: flexor muscles of stomach. the lesson built on lesson 1, where the back extensors were integrated with the abdominal and anterior musculature. the participant was taught to integrate the muscles and the movements using the hip muscles, allowing for the agonists and antagonists to work together. • lesson 3: muscles of the waist. this lesson concentrated on the waist muscles, such as the internal and external obliques, and the quadratus lumborum. the point of the lesson was to increase the muscle length at the waist and decrease the feeling of tightness in the obliques and the quadratus lumborum. • lesson 4: controlling muscles involved in trunk rotation. this lesson took advantage of the growing sensitivity and control attained in lessons 1 3. the main movements were rotational movements of the trunk muscles (quadratus lumborum, abdominals, back extensors), with attention to the elongation (lengthening) and awareness of the function of the trunk muscles. • lesson 5: hip and leg muscles. in this lesson, the participant was taught how to free the muscles of the trunk, hips, legs and feet. the basics of locomotion and the freeing up of movement along the entire lower body were analysed. • lesson 6: neck and shoulders. this lesson focused on increasing upper body awareness, freeing up the ribs, chest, shoulders and neck, and increasing the movements of the upper body. • lesson 7: breathing. the focus of this lesson was on breathing, specifically breathing done with the diaphragm. • lesson 8: walking. this lesson built on what had been achieved in lessons 1 7. it taught walking with proper trunk, spinal and shoulder rotation, as well as the rotation experienced by the arms and legs. it emphasised the contralateral walking pattern, and making walking effortless and graceful. combination group the combination group had to combine both the aerobic exercise and the somatic awareness exercise in the same session on the same day (they were not allowed to pick only one). they were required to do both exercises a minimum of three times a week for a period of 8 weeks. on the days they chose to do aerobic exercise, they had to undergo the aerobic exercise protocol described above as well as the somatic awareness exercise (see table 2). exercise group the exercise group was instructed to continue with their aerobic programmes, but somatic awareness exercise was added. they had to complete aerobic exercise and the somatic awareness exercise at least three times a week for 8 weeks (see table 2). ethical considerations the present study was granted ethical approval by the ethical committee of the university of johannesburg prior to its commencement. a letter of information was issued to each participant, including an informed consent form. data analysis frequency and descriptive statistics were conducted to describe the sample. the mean scores and sds for both the preand post-test of the pss were calculated. statistical significance was set at p<0.05 for the study. normality was determined by the kolmogorov-smirnov test and the shapiro-wilk test. a normal distribution was found for all pss preand post-test measures in all the intervention groups, except for the post-test of the somatic group. paired-sample t-tests were done to determine within-group changes in pss after the interventions, and the effect size was determined by calculating the eta2 statistic. guidelines for interpretation of the effect size were: 0.01 0.06: small effect; 0.07 0.14: moderate effect; and >0.14: large effect. a one-way analysis of variance (anova) and post-hoc tests (dunnett t3) were conducted to determine group differences. results the results of the pss scores and the distribution of the demographics of each group are shown in table 3. after statistical analysis, there was no statistically significant difference in compliance between the somatic, combination and table 3. mean pss pretest and post-test scores, mean differences, significance and effect size of all five groups variable group pretest, mean (sd) post-test, mean (sd) mean preand post-test difference p-value effect size (eta2) pss aerobic 18.80 (5.60) 14.20 (6.64) –4.60 0.02 0.33 somatic 24.11 (3.44) 15.44 (5.46) –8.67 0.01 0.76 combination 23.38 (6.35) 16.63 (3.62) –6.75 0.01 0.76 exercise 25.44 (4.04) 18.33 (5.17) –7.11 0.01 0.75 control 19.47 (5.68) 18.87 (5.83) –0.60 0.66 pss = perceived stress score; sd = standard deviation. 108 sajsm vol. 26 no. 4 2014 exercise groups. however, while the aerobic exercise group did have a statistically significant increase in compliance, it did not positively affect objective stress measures, nor did less participation in aerobic exercise negatively affect the objective stress measures. thus, one may assume that compliance in the aerobic exercise group did not affect the current study. discussion there were statistically significant decreases in the perceived stress of all the experimental groups, and although the perceived stress results for the control group decreased, this decrease was not statistically significant. a small effect size was found for the aerobic group, indicating that aerobic exercise was only slightly effective in decreasing perceived stress. a key finding in this study, however, was the large effect sizes found with the experimental groups that did somatic awareness exercise (somatic, combination and exercise groups); the perceived stress score decreased significantly in these groups. the large effect size of somatic awareness exercise may be due to its properties, which are not present in aerobic exercise. although it may seem that aerobic exercise and the use of stretching promote somatic awareness, they do not, as they do not focus on somatic awareness principles such as teaching of motor movements, improved kinaesthetic awareness,[17] sensory processing,[18] internal feedback and internal attention.[19] thus, by allowing improved feedback processing, stressor perception and emotional regulation, there is an improvement (decrease) in perceived stress.[20] the combination group had a statistically significant decrease in perceived stress scores, and a larger effect size than the group that participated in aerobic exercise only, because the combination of two or more modes has been shown to be more effective than one alone. the exercise group also had a statistically significant decrease with a large effect size.[17] it is interesting to note that while the participants in this group were exercising, they still had high levels of perceived stress. however, regardless of what their exercise modalities were, the addition of the somatic awareness exercise brought about the large effect size and the decrements in the perceived stress score. these results indicate that somatic awareness exercise is a more effective physical mode than the other modes in this study than the other modes in this study in reducing perceived stress, whether it is used alone or in conjunction with other cardiovascular modes, in both trained and untrained individuals. since perceived stress can be reduced by various physical modalities, the results of this study indicate how beneficial it could be to add somatic awareness training (which includes combinations of breathing, mindfulness, movement and inner sensing) to any physical mode in order to reduce perceived stress in individuals who are experiencing moderate to high stress levels. there are a few recommendations according to the limitations of the study. firstly, the sample could be larger, with a more evenly distributed gender and ethnicity profile. secondly, the specific protocol utilised in the study could not be found in other studies. in order to test its reliability, one should repeat the study and compare it with other mindfulness techniques such as yoga, tai chi and mindfulnessbased stress reduction. conclusion on the basis of the results of the present study, it may be concluded that various physical modes such as aerobic exercise, somatic awareness training and the combination of the two may be used to decrease perceived stress levels in moderately to highly stressed individuals who are sedentary or who are physically active. however, the results suggest that somatic awareness exercise is a more effective physical mode than the other modes in this study in reducing perceived stress, whether it is used alone or in conjunction with other cardiovascular modes, in both trained and untrained individuals. references 1. cohen s, kamarck t, mermelstien r. a global measure of perceived stress. j health soc behav 1983;24(4):385-396. 2. chrousos gp. stress and disorders of the stress system. nat rev endocrinol 2009;5(7):374-381. [http://dx.doi.org/10.1038/nrendo.2009.106] 3. cohen s, janicki-deverts d, miller ge. psychological stress and disease. jama 2007;198(14):1685-1687. [http://dx.doi.org/10.1001/jama.298.14.1685] 4. health and safety executive. stress and psychological disorders, 2011. http://www. hse.gov.uk/statistics/causdis/stress/stress.pdf (accessed 26 september 2012). 5. coopmans jwm. stress related causes of presenteeism amongst south african managers. mphil dissertation. pretoria: university of pretoria, 2007. 6. lilford n. absenteeism reaches new heights in south africa, 2010. http:// www.hrfuture.net/wellness/absenteeism-reaches-new-heights-in-south-africa. php?itemid= 183 (accessed 3 october 2012). 7. brook dw, rubenstone e, zhang c, morojele nk, brook js. environmental stressors, low well-being, smoking, and alcohol use among south african adolescents. soc sci med 2011;72(9):1447-1453. [http://dx.doi.org/10.1016/2011.02.041] 8. westaway ms. the impact of chronic diseases on the health and well-being of south africans in early and later old age. arch gerontol geriatr 2010;50(2):213-221. [http:// dx.doi.org/10.1016/j.archger.2009.03.012] 9. granath j, ingvarsson s, von thiele u, lundberg u. stress management: a randomised study of cognitive behavioural therapy and yoga. cogn beav ther 2006;35(1):3-10. [http://dx.doi.org/10.1080/16506070500401292] 10. bond ds, lyle rm, tappe mk, seehafer rs, d’zurilla tj. moderate aerobic exercise, t’ai chi, and social problem-solving ability in relation to psychological stress. int j stress manag 2002;9(4):329-343. [http://dx.doi.org/10.1023/a:1019934417236] 11. cox rh. sports psychology concepts and applications. 5th edition. new york: mcgraw-hill, 2002. 12. hansen cj, stevens lc, richard cj. exercise duration and mood state: how much is enough to feel better? health psychol 2001;20(4):267-275. [http://dx.doi. org/10.1037//0278-6133.20.4.267] 13. hanna t. the body of life: creating new pathways for sensory awareness and fluid movement. rochester, usa: healing arts press, 1993. 14. american college of sports medicine. pre-exercise evaluations. in: whaley mh, brubaker ph, otto rm, eds. acsm’s guidelines for exercise testing and prescription. 7th ed. philadelphia: lippincott williams & wilkins, 2006:79-173. 15. benham g. the highly sensitive person: stress and physical symptom reports. pers individ dif 2006;40(7):1433-1440. [http://dx.doi.org/10.1016/j.paid.2005.11.021] 16. baechle tr, earle rw. essentials of strength training and conditioning. champaign, usa: human kinetics, 2000. 17. alexander fm. constructive conscious control of the individual. london: victor gollancz ltd, 1987. 18. kilpatrick la, suyenobu by, smith sr, et al. impact of mindfulness-based stress reduction training on intrinsic brain connectivity. neuroimage 2011;56(1):290-298. [http://dx.doi.org/10.1016/j.neuroimage.2011.02.034] 19. kerr ga, kotynia f, kolt g. feldenkrais awareness through movement and state anxiety. j bodyw mov ther 2002;6(2):102-107. [http://dx.doi.org/10.1054/jbmt.2001.0274] 20. dobkin pl. mindfulness-based stress reduction: what processes are at work? complement ther clin pract 2008;14(1):8-16. [http://dx.doi.org/10.1016/j.ctcp.2007.09.004] sajsm vol. 27 no. 2 2015 55 traumatic iliopsoas haematoma is a serious complication of haemorrhage disorders rarely seen in young healthy athletes. it is mostly described in patients on anticoagulant therapy and commonly associated with various degrees of femoral nerve palsy. a 22-year-old male rugby player presented with severe onset of pain in the lower back, right hip flexor/pelvic area following a tackle during a rugby match. magnetic resonance imaging identified a distinct, hyperechoic heterogeneous mass within the right iliopsoas muscle, confirming a diagnosis of iliopsoas haematoma. the case resolved completely after conservative medical treatment in addition to a period of rest and intense active physical therapy. this case study reports the rare diagnosis of an uncomplicated iliopsoas haematoma following a sports injury in a young athlete. s afr j sports med 2015;27(2):55-57. doi:10.7196/sajsm.612 iliopsoas haematoma in a rugby player d c janse van rensburg,1,2 md, phd, facsm; o strauss,1,3,4 mb chb, msc (sports med); m d velleman,1,5 mmed (radd), fcrad(d); a jansen van rensburg,1,2 msc; c c grant,1,2 phd 1 section sports medicine, faculty of heath sciences, university of pretoria, south africa 2 exercise smart team, university of pretoria, south africa 3 high performance centre, university of pretoria, south africa 4 blue bulls rugby union, pretoria, south africa 5 little company of mary medical centre, pretoria, south africa corresponding author: d c janse van rensburg (christa.jansevanrensburg@up.ac.za) classified as either spont a n e o u s or t r au m at i c , [ 1 ] iliopsoas muscle haematomas are rare lesions that typically appear in individuals presenting with clotting difficulties, whether due to illnesses, such as haemophilia[2] and other blood disorders, or as a result of anticoagulant treatment.[3] clinical signs and symptoms of iliopsoas haematoma are often vague and nonspecific and may include pelvic, back, lower abdominal, or groin and thigh pain or swelling. muscle haemorrhage may lead to flexion deformity of the hip and may be associated with the functional inability of the affected limb.[2] femoral neuropathy due to the compression of the femoral nerve is the most serious and common complication.[2,4] i l i o p s o a s h a e m a t o m a i s m o s t l y described as an infrequent complication of anticoagulation therapy in older patients, however it has rarely been noted in athletes or in sports-associated incidents.[2,4,5] we report a case that occurred following a closed injury of the iliopsoas muscle in a young rugby player after he was tackled during a game. case report this report describes a case of a 22-year-old rugby player who complained of pain in the right hip flexor muscle and lower back areas three days after a rugby match in august 2013. during the first half of the match the player injured his hip when he was tackled and twisted his pelvic area. he was only removed from the field of play later in the game, during the second half, complaining of lower back pain. on examination directly after the game, he had no pain and full strength with flexion of the right iliopsoas and rectus femoris muscles and no pain on adduction of the right leg. examination of the lower back was also pain free with a normal range of motion of the vertebral column. his symptoms subsided and no immediate treatment was given. three days after the game he complained of excessive pain in the lower back, right hip flexor/pelvic area. on examination he now had pain on palpation of the right hip flexor muscles. there was no pain on resistant flexion movements of both the deep and superficial hip flexor muscles. the examination of the lower back area was still pain free on palpation, but he had some pain with flexion of the vertebral column. he had no pain with the adductor squeeze test or when doing a sit-up. he also had no pain on adduction or abduction of his right leg. the faber test of the right hip was negative. a possible deep hip flexor muscle strain or lower back injury was suspected. the player was referred for a magnetic resonance imaging (mri) scan of his lower back and pelvic area. the mri lumbar spine scan (1.5 tesla siemens symphony tim system) revealed o e d e m a i n t h e r i g ht p s o a s mu s cl e, extending from l1 to l5. centrally in this region of oedema, a more complex area of heterogeneous signal changes of ~3 5 cm diameter was noted, consistent with subacute haematoma (fig. 1). the right psoas muscle was also larger than the left (fig. 2). a second field of signal changes in the fig. 1. short tau inversion recovery (stir) coronal images demonstrating oedema and circumscribed haematoma in right psoas muscle (red arrow). case study 56 sajsm vol. 27 no. 2 2015 right deep gluteal region adjacent to the right greater trochanter was present, representing haemorrhage and oedema in relation and between the gluteus medius and minimus muscles on the right. no evidence of underlying bony involvement or significant lumbar disc pathology was present (fig. 3). treatment was initialised after confirmation of the diagnosis. treatment consisted of rest from all rugby and conditioning activities for 14 days. the player also received symptomatic physiotherapy treatment consisting of antiinflammatory modalities, and soft tissue mobilisation of muscle around the right hip flexor muscle area. a 10-day course of oral analgesic tablets was prescribed. the patient was pain free on walking and resistant hip flexor muscle movements after 14 days. he had normal range of motion of the right hip. a gradual running programme was introduced together with resistance training. sportspecific conditioning commenced after 21 days, and after 28 days he was asymptomatic and returned to full rugby training. discussion reports of haematomas of the iliopsoas muscle in young athletes injured during sports events have only rarely been published. [1,6] we report a 22-year-old rugby player that developed an iliopsoas muscle haematoma where the mechanism of injury was most likely excessive muscle strain during a match. the iliopsoas comprises three muscles passing through the pelvis. the origins are on the lumbar vertebrae (psoas major and psoas minor muscles) and the inner pelvis (iliacus muscle) and inserts into the lesser trochanter on the femur.[4] it is the strongest flexor of the hip joint, and with minimal elastic properties, opposes extension of the hip. these muscles are essential in the support of posture and hip flexion. they work together to flex the hip when kicking, bringing the leg out in front of the body or the knee up towards the chest when running.[2] mechanisms of injury to the iliopsoas may be due to sudden contraction of the hip flexor muscles while the hip is in a stretched position or during sprinting or kicking activities with the hip extended and stretched above its flexible limit.[7] a sudden movement of the hip into extension from a flexed and externally rotated position, certain movements such as flexion-extension (raising and lowering the entire leg) or rotation (twisting of the hip) may also contribute to an injury.[7] patients often present with undifferentiated symptoms including sudden onset of severe pain, muscle dysfunction and, in acute cases, with nerve palsy primarily affecting the femoral nerve.[5,8] the flexed position imposes the least tension on the iliopsoas muscle whereby the muscle is relaxed, with pain and limitation on passive hip extension as the muscle is stretched.[9] owing to the strong fibrous tissue layers of the muscle, large volumes of intramuscular bleeding are entrapped causing severe pain as a result of pressure build-up. inhibition of muscular function with femoral nerve involvement could present a serious and potentially severe neurological dysfunction. urgent drainage procedures of a traumatic haematoma may vary from open surgery,[3,8] to percutaneous drainage,[5] laparoscopy[1] or the most recently described retroperitoneoscopic approach.[10] the haematoma itself may account for a fatal outcome because of massive blood loss and haemorrhagic shock, especially with delayed diagnosis.[8] depending on the rate of active bleeding and the degree of impairment, treatment of an iliopsoas haematoma remains conservative comprising a period of total inactivity, adequate analgesia and gentle physiotherapy to allow the haematoma to spontaneously resorb.[2,3,9] in cases where an iliopsoas haematoma diagnosis is suspected, an mri scan is the imaging modality of choice due to its high sensitivity and specificity in the detection of small haematomas.[8,9] in patients presenting with femoral neuropathy as a consequence of retroperitoneal bleeding, an mri scan will assist in ruling out nerve root compression or spinal problems. in view of its usefulness in studying deep soft tissue, ultrasonography, although being operator-dependent and influenced by surrounding organs, may also provide valuable information in detecting these lesions.[6] computed tomography scans are frequently used in diagnosis as they are more readily accessible.[5,10] clinical knowledge remains fundamental and a degree of suspicion in the diagnosis is needed due to the insidious incidence of neurological disorders. haematoma of the iliopsoas muscle resulting from sport activities is an extraordinary diagnosis. this case in a 22-year-old rugby player had an uncomplicated course and completely resolved following early detection and diagnosis. fig. 2. t1 (left) and t2 (right) axial images depicting a haematoma in the right psoas muscle (red arrow). the right psoas muscle is larger than the left. fig. 3. t2 midsagittal image (left) and stir right parasagittal image (right), indicating no evidence of lumbar disc pathology, showing oedema in right psoas muscle (red arrows). sajsm vol. 27 no. 2 2015 57 consent written informed consent was obtained from the patient for publication of this case report and any accompanying images. a copy of the written consent is available for review. references 1. jing j, qian j, tian d, zhang j, chen l, tang j. laparoscopic treatment of traumatic iliopsoas hematoma. chin med j (engl) 2013;126(4):795-797. 2. canelles e, bruna m, roig jv. spontaneous hematoma of the iliopsoas muscle: the report of three cases and review of the literature. rev esp cir ortop traumatol (english edition) 2010;54(4):234-237. [http://dx.doi.org/10.1016/s19888856(10)70238-8] 3. kong wk, cho k, lee hj, choi j. femoral neuropathy due to iliacus muscle hematoma in a patient on warfarin therapy. j korean neurosurg soc 2012;51(1):51-53. [http:// dx.doi.org/10.3340/jkns.2012.51.1.51] 4. tamai k, kuramochi t, sakai h, iwami n, saotome k. complete paralysis of the quadriceps muscle caused by traumatic iliacus hematoma: a case report. j orthop sci 2002;7(6):713-716. [http://dx.doi.org/10.1007/s007760200127] 5. patel a, calfee r, thakur n, eberson c. non-operative management of femoral neuropathy secondary to a traumatic iliacus haematoma in an adolescent. j bone joint surg br 2008;90(10):1380-1381. [http://dx.doi.org/10.1302/0301-620x.90b10.21040] 6. kameda t, fujita m, takahashi i. diagnosis of traumatic iliopsoas hematoma using point-of-care ultrasound. crit ultrasound j 2011;3(1):59-61. [http://dx.doi.org/10.1007/s13089-011-0065-4] 7. anderson k, strickland sm, warren r. hip and groin injuries in athletes. am j sports med 2001;29(4):521-533. 8. conesa x, ares o, seijas r. massive psoas haematoma causing lumbar plexus palsy: a case report. j orthop surg (hong kong) 2012;20(1):94-97. 9. basheer a, jain r, anton t, rock j. bilateral iliopsoas hematoma: case report and literature review. surg neurol int 2013;4:121-121. [http://dx.doi.org/10.4103/2152-7806.118561] 10. qian j, jing j, tian d, zhang j, chen l. safety and efficacy of a new procedure for treating traumatic iliopsoas hematoma: a retroperitoneoscopic approach. surg endosc 2014;28(1):265-270. [http://dx.doi.org/10.1007/s00464-013-3183-1] sajsm vol. 25 no. 2 2013 39 original research objective. to document the prevalence and nature of running-related musculoskeletal injuries among recreational half-marathon runners over a 12-month period (1 july 2011 31 june 2012). methods. data were collected from runners (n=200) who officially ran half-marathon road races during february june 2012. runners, whose participation in the study was dependent on voluntary informed consent, were required to complete a self-report questionnaire probing the prevalence and nature of running musculoskeletal injuries in the 12 months preceding recruitment. probability was set at p≤0.05. results. one hundred and eighty (90%) runners reported sustaining musculoskeletal injuries (p<0.001). the anatomical site most vulnerable to injury was the knee (26%), followed by the tibia/fibula (22%) and the lower back/hip (16%) (p<0.001). the intrinsic factors predisposing runners to musculoskeletal injuries were deviant quadriceps and hip flexion angles (p≤0.05). conclusion. recreational runners in our cohort sustained a high prevalence of knee, tibia/fibula and lower back/hip injuries. s afr j sm 2013;25(2):39-43. doi:10.7196/sajsm.360 common running musculoskeletal injuries among recreational half-marathon runners in kwazulu-natal t j ellapen, phd; s satyendra, bsps (hons) (biokinetics); j morris, bsps (hons) (biokinetics); h j van heerden, dphil department of sport science, school of physiotherapy, sport science and optometry, university of kwazulu-natal, durban, south africa corresponding author: t j ellapen (tellapen1@yahoo.com) predisposing factors contributing to musculoskeletal running injuries include poor training habits, inadequate rehabilitation of previous injuries, high weekly mileage, incorrect shoes and muscle imbalances. [1-4] studies have identified the knee as the anatomical site most vulnerable to running-related musculoskeletal injury, followed by the ankle.[1-4] intrinsic factors such as deviant quadriceps angles (q-angles), genu varum, genu valgum, rear foot varus and rear foot valgus have been associated with vulnerability to knee and ankle injuries.[1,5,6] there is controversy concerning the relationship between deviant q-angles and knee injuries among runners.[7,8] lun et al.[7] and messier et al.[8] have reported that deviant q-angles do not play a significant role in the predisposition towards knee injuries, while others[6,9,10] advocate that large q-angles are a positive risk factor for knee injuries among runners. only one south african study has investigated the association of deviant q-angles and knee injuries among runners.[6] there is a need for further epidemiological investigations to determine intrinsic risk factors that predispose runners to musculoskeletal injuries. we aimed to compare training habits, q-angles and hip flexion between runners who did, and those who did not incur running injuries in the 12 months preceding study recruitment. methods participants we performed a retrospective and descriptive study of the prevalence of running-related musculoskeletal injuries in the preceding 12 months among 200 runners, aged 18 57 years, from different athletic clubs affiliated to the kwazulu-natal athletic association. ethical approval for the study was obtained from the school of health science research committee, university of kwazulu-natal. the cohort regularly participated in half-marathons (21.1 km), with an average road-running history of 12.2 years (standard deviation (sd) ±1.4). runners participated in the study by signing voluntary informed consent. their personal details, training histories and running-related injuries were obtained using a self-report, validated, musculoskeletal injury questionnaire adapted from van heerden.[11] questionnaire participants were requested to indicate only running-related musculoskeletal injuries experienced as a sensation of distress or agony, and which prevented them from physical activity for a minimum of 24 hours (adapted from van herdeen[11]). in the self-report questionnaire, the running-related musculoskeletal injuries were further investigated according to anatomical site of musculoskeletal pain, intensity/severity of pain (according to the kee and seo[12] pain-rating scale) and symptoms (dull aching, discomfort, sharp, pins and needles, numbness, burning and radiating).[12] hagglund et al.[13] reported that the fundamental problem concerning international epidemiological sport investigations is the inconsistent definition of musculoskeletal injury.[13] the authors proposed that the prevalence of musculoskeletal injury can be established, if the following is documented: anatomical site, sustained type and severity of pain measured by a validated pain-rating scale.[13] pain was employed in the questionnaire because it is a discernible symptom of musculoskeletal injury. the questionnaire also contained a training history section that attempted to determine whether weekly running mileage was a contributing factor to musculoskeletal injury. training history was determined by recording training schedules according to the frequency of training sessions per week, the distance run during mailto:tellapen1@yahoo.com 40 sajsm vol. 25 no. 2 2013 each training session, and training type (slow long distance, tempo, time trial, intervals and recovery). anthropometric measurements in addition to information probed by the questionnaire, the following anthropometric measurements were recorded: body mass, stature, q-angle and hip flexion (thomas test). the objective was to determine whether a significant relationship existed between these intrinsic factors and musculoskeletal injury. we measured the q-angle according to livingston and spaulding. [14] the runner lay supine on the plinth with foot in neutral position. the anterior superior iliac spine (asis), the centre of the patella and the tibial tuberosity, were marked using a pen. the centre of the goniometer was placed on the centre of the patella (found by the intersecting width and length lines). the stationary arm of the goniometer was aligned with the asis and the movable arm was aligned with the tibial tuberosity. a third vertical line that extended from the tibial tuberosity along the femur allowed the formation of an angle. three readings were taken for each runner by the same investigator (to ensure test-re-test reliability). the thomas test measured the tightness of the hip flexors (rectus femoris and iliopsoas) according to starke and ryan.[15] the runner lay supine on the plinth with their knees bent and lower limb hanging over the edge. the runner’s posterior thighs lay against the surface of the plinth. the greater trochanter and lateral femoral condyle of the ipsilateral leg were identified and a line was drawn between these two landmarks. the first clinician aligned the stationary arm of the goniometer onto the greater trochanter and the line drawn of the ipsilateral thigh. the second clinician passively flexed the contralateral hip bringing the knee to the chest (contra-lateral hip and knee flexed). the movable arm of the goniometer was then aligned to the drawn line of the ipsilateral thigh as the contra-lateral hip was flexed. the angle created by the intersection of the stationary and movable lines was measured. three readings were taken for each subject by the same investigator (to ensure test-re-test reliability). statistical analysis we used descriptive statistics including mode, mean, frequency and percentages, and inferential statistics comprising levene’s test, chisquare and t-tests. the levene’s test was used to assess the homogeneity variance that revealed unequal variance (p<0.05). a two-tailed t-test adjusted for unequal variance was employed to assess the statistical comparative significance of the injured v. non-injured runners. the probability level was set at p<0.05. results the cohort (n=200) comprised 120 males (60%) and 80 females (40%), of white (50%), indian (33%), african (12%) and coloured (6%) race (table 1); and 180 (90%) participants experienced a collective total of 294 running injuries (p<0.001). male (n=107) and female (n=73) runners experienced 178 and 116 running injuries, respectively. the point prevalence of the anatomical site of these injuries is presented in table 2. the kee and seo[12] pain-rating scale (1 = uncomfortable, 2 = mild, 3 = moderate, 4 = severe and 5 = worst experienced) was employed to subjectively rate the intensity of running-related musculoskeletal pain. among those who experienced running injury, a score of 3 (moderate pain intensity) was rated the most prevalent (42.46%), followed by a score of 2 (32.4%), 4 (11%), 1 (8%) and 5 (7%) (p<0.01). the most common symptoms associated with running injuries were dull aching (43%), followed by sharp (20%), discomfort (13%), burning (10%), radiating (4%), pins and needles (4%), swelling (3%) and numbness (3%) (p<0.01). the anthropometric measurements of the runners are presented in tables 5 and 6. runners addressed specific components of their running conditioning on set weekdays, thereby prescribing a rigid weekly training schedule and enabling us to monitor their training habits (tables 3 and 4). in addition to the prerequisite running training, participants were required to report whether they performed any cross-training. the female runners ran an average of 11.3 months per year (sd ±0.5) including 4.4 sessions per week (sd ±1.4), while the male runners ran an average of 11.0 months per year (sd ±0.6) including 4.0 sessions per week (sd ±1.3). regarding cross-training activities, 48 female runners engaged in resistance strength training (n=30) and swimming (n=18), while 58 male runners engaged in resistance strength training (n=37), swimming (n=14), action cricket (n=4) and touch rugby (n=2). male and female runners who cross-trained also sustained running injuries. the comparative statistical analyses of the training mileage of noninjured v. injured runners revealed no statistical significance (p>0.05); injured female runners completed 499 km, while non-injured females completed 509 km during the 12-month period (p>0.05). during this time, the injured females sustained a total of 116 injuries. both injured and non-injured male runners completed 506 km during the 12-month period (p>0.05), with the injured male runners sustaining a total 178 injuries. discussion among the 200 runners sur veyed, 180 (90%) experienced running-related musculoskeletal injury within the preceding 12 table 1. participant demographics (n=200) variables males (n=120) females (n=80) age (years), mean (±sd) 44.3 (±12.7) 42.9 (±12.5) body mass (kg), mean (±sd) 73.6 (±12.1) 60.7 (±7.8) stature (m), mean (±sd) 1.73 (±0.08) 1.6 (±0.07) bmi (kg/m2), mean (±sd) 24.3 (±3.4) 22.7 (±3.07) running experience (years), mean (±sd) 13.2 (±10.5) 11.2 (±9.2) sd = standard deviation; bmi = body mass index. sajsm vol. 25 no. 2 2013 41 months (p<0.0001), in line with previous literature.[2,4,16] statistical interrogation of the data revealed that the lower extremities (lower back/hip, thigh, knee, tibia/fibula, ankle and foot) experienced the most musculoskeletal injuries (96%), followed by the upper extremities (shoulder, elbow and hand) (3%) and neck (1%) (p<0.001). marti et al.[3] and van mechelen[4] reported a prevalence of musculoskeletal running injuries in the lower extremities of 70% and 80%, respectively. [3,4] powell[5] and van gent et al.[16] reported that table 3. comparative analyses of the mean weekly run mileage of injured v. non-injured male runners (n=120) training components injured (n=107) non-injured (n=13) p-value long slow distance (km), mean (±sd) 21.6 (±10.36) 21.3 (±8.08) >0.05 tempo (km), mean (±sd) 9.6 (±4.5) 8.0 (±3.4) >0.05 time trial (km), mean (±sd) 6.0 (±2.0) 7.7 (±1.6) <0.05 hill (km), mean (±sd) 7.1 (±4.6) 6.0 (±5.2) >0.05 recovery (km), mean (±sd) 8.8 (±5.8) 10.1 (±5.3) >0.05 weekly mileage (km), mean (±sd) 10.6 (±6.2) 10.6 (±6.1) >0.05 sd = standard deviation. table 2. percentage reflection of the point prevalence of musculoskeletal injury at various anatomical sites* anatomical site males (n=107) % females (n=73) % mean % neck 1.7 0.9 1.3 shoulder 1.1 1.7 1.4 elbow 0.6 0.0 0.3 hand 1.1 0.9 1.0 lower back/hip 15.2 16.4 15.8 thigh 15.7 11.2 13.5 knee 27.0 25.9 26.4 tibia/fibula 20.2 23.3 21.7 ankle 12.4 7.8 10.1 foot 5.1 12.1 8.6 *p<0.001. table 5. comparative analyses of the mean q-angles of runners with knee injuries v. those with non-knee injuries (n=200) q-angle non-injured injured p-value male right q-angle (°), mean (±sd) left q-angle (°), mean (±sd) n=72 9.1 (±1.2) 9.6 (±1.3) n=48 10.9 (±3.2) 10.4 (±2.1) <0.01 <0.05 female right q-angle (°), mean (±sd) left q-angle (°), mean (±sd) n=50 12.4 (±1.9) 12.7 (±1.7) n=30 13.4 (±2.4) 14.2 (±2.9) >0.05 <0.01 q-angle = quadriceps angle; sd = standard deviation. table 4. comparative analyses of the mean weekly run mileage of injured v. non-injured female runners (n=80) training components injured (n=107) non-injured (n=13) p-value long slow distance (km), mean (±sd) 18.4 (±7.2) 17.5 (±3.1) >0.05 time trial (km), mean (±sd) 4.6 (±1.3) 5.1 (±1.9) >0.05 recovery (km), mean (±sd) 7.6 (±3.1) 8.8 (±1.3) >0.05 weekly mileage (km), mean (±sd) 10.2 (±7.2) 10.4 (±6.3) >0.05 sd = standard deviation. 42 sajsm vol. 25 no. 2 2013 a widespread predisposing factor responsible for lower extremity musculoskeletal injury among runners is a high running weekly mileage. however, the comparative statistical analyses of the run training mileage of the non-injured v. injured runners revealed no statistical significance in our study (p>0.05). this suggests that the running mileage was not a contributing factor that predisposed the runners to musculoskeletal injury. the knee was the most susceptible anatomical site to musculoskeletal injury (p<0.001), in agreement with previous findings.[6,16] puckree et al.[6] documented that the presence of deviant q-angles among male runners predisposes them to musculoskeletal knee injury. the q-angle is an indicator of the muscle symmetry of the quadriceps femoris muscle surrounding the knee. larger q-angles increase the compressive forces applied to the lateral facet of the patella, and increase the tensile forces on the medial patellar restraint (collectively producing musculoskeletal pain and discomfort).[6,18] repetitive and prolonged stressing of the medial patellar restraint reduces its effectiveness against traction force of the lateral patellar restraint. this medial patellar restraint inefficiency results in lateral patella tracking, indicated by the abnormal q-angle (p<0.05), which precipitates the onset of patellar femoral pain syndrome.[14,17] consistent with puckree et al.,[6] male runners in our cohort who sustained musculoskeletal knee injuries had larger deviant q-angles, differing significantly from non-injured runners (p<0.05). this suggests that q-angle deviation was a predisposing factor to musculoskeletal knee injuries among these male runners. to our knowledge, no published literature examines the association of knee injuries and q-angles among females. in our study, the left q-angle of female runners who sustained knee injuries was significantly greater than that of non-injured runners (p<0.05), suggesting a stronger vastus lateralis than vastus medialis in the former. the second-most vulnerable anatomical site to musculoskeletal injury was the tibia/fibula, supporting similar findings by stergiou et al.[18] who postulated that the excessive pronation of the subtalar joint increases the torsional forces up the tibia and fibula, producing injuries. this torsional force is a result of the ground reaction forces transferred to the plantar surface of the foot that changes the rear foot angle, which alters the amount of pronation at the subtalar joint and propagates increased torsional forces up the lower limb.[18] the prevalence of lower back/hip injury among the runners (p<0.001) was a unique finding with regard to previous running epidemiological investigations. runners who sustained lower back/ hip injuries had greater hip flexion angles (as measured by the thomas test) than non-injured runners. furthermore, the hip flexion angles of female runners who sustained lower back/hip musculoskeletal injuries differed significantly from those of their non-injured counterparts (p<0.01); there is no literature to explain this finding. it is postulated that the tight hip flexors produce an anterior pelvic tilt which alters the normal length tension relationship between the hip posterior rotators/extensors and anterior hip rotators/flexors.[19] prolonged anterior tilting of the pelvis shortens the iliopsoas and elongates the gluteal muscles; this asymmetry muscle development creates an abnormal force couple, facilitating muscle spasms in the hip flexors and strains in the hip extensors yielding symptoms of dull aching sensations.[19] in our study, the most common symptoms associated with running injuries were dull aching (42.46%), followed by sharp (20%), discomfort (13%), burning (10%), radiating (4%), pins and needles (4%), swelling (3%) and numbness (3%). mansfield and neumann[19] identified dull aching, sharp pain and discomfort sensations as muscle injury. the combination of dull aching, sharp and discomfort in our study suggests that the runners experienced a higher percentage of muscle injury (7%). this, in combination with the data from the anatomical site of musculoskeletal pain, the severity of the musculoskeletal pain sustained and the identification of the type of pain sensation experienced indicated the prevalence of running musculoskeletal injuries. conclusion runners experienced a high prevalence of knee, lower back/hip and tibia/fibula musculoskeletal injuries, consistent with previous research findings.[5-10] knee and lower back/hip injuries have been associated with deviant q-angles and tight hip flexors, respectively. the findings of this study can be best utilised if athletic coaches and runners take cognizance of them and seek professional help to alleviate the high prevalence of musculoskeletal injury, by engaging in rehabilitative and preventive exercises. in addition, runners should be educated on various ways to prevent injury by adhering to appropriate training regimens, alterations in running technique and appropriate foot wear selection. a limitation of our study was the recall bias of the retrospective reporting of musculoskeletal injury and training volumes. future epidemiological running injury studies should be limited to smaller age ranges, as some older individuals may have had significantly different physiological and biomechanical capacities. the inclusion of the thomas test added value to the findings of the intrinsic nature of the lower table 6. comparative analyses of the mean hip flexion angles (thomas test) of runners with lower-back/hip injuries v. those with non-lower-back/hip injuries (n=200) hip flexion angle non-injured injured p-value males n=93 n=27 right hip (°), mean (±sd) 7.9 (±2.9) 8.03 (±2.2) >0.05 left hip (°), mean (±sd) 7.6 (±2.9) 7.9 (±2.4) >0.05 females n=61 n=19 right hip (°), mean (±sd) 6.6 (±1.7) 12.6 (±2.2) <0.01 left hip (°), mean (±sd) 6.8 (±2.1) 13.2 (±2.5) <0.01 sd = standard deviation. sajsm vol. 25 no. 2 2013 43 back/hip musculoskeletal injuries experienced by female runners. future studies are required to validate our findings and to better understand the association of the mechanisms by which intrinsic factors predispose runners to musculoskeletal injuries. references 1. noakes t. the lore of running. 4th ed. leeds, uk: human kinetics, 2001:973-1041. 2. taimela s, kujalo m, oesteiman k. intrinsic risk and athletic injuries. sport med 1990;9:205-218. 3. marti b, vader jp, minder ce, abelin t. on the epidemiology of running injuries. am j sport med 1988;16:285-294. 4. van mechelen w. running injuries: a review of the epidemiological literature. sport med 1992;14:320-335. 5. powell ke. an epidemiological perspective on the cause of running injuries. physician sport med 1986;14(6):100-108. 6. puckree t, govender a, govender k, naidoo p. the quadriceps angle and the incidence of knee injury in indian long distance runners. south african journal of sports medicine 2007;19(10):9-11. 7. lun v, meeuwisse wh, stergiou p, stefanyshyn d. relation between running injury and static lower limb alignment in recreational runners. br j sport med 2004;38:576580. [http://dx.doi.org/10.1136/bjsm.2003.005488] 8. messier sp, davis se, curl ww, lowery rb, pack rj. etiologic factors associated with patellofemoral pain in runners. med sci sports exerc 1991;23:1008-1015. 9. ivkovic a, franic m, bolanic i, pecina m. overuse injuries in female athletes. croet med j 2007;48(6):767-778. [http://dx.doi.org/10.3325/cmj.2007.6.767] 10. warvasz gr, mcdermott ay. patellofemoral pain syndrome (pfps): a systematic review of anatomy and potential risk factors. dyn med 2008;7:9. [http://dx.doi. org/10.1186/1476-5918-7-9] 11. van heerden hj. pre-participation evaluation and identification of aetiological risk factors in epidemiology of sports injuries among youths. phd thesis. pretoria: university of pretoria, 1996. 12. kee d, seo sr. musculoskeletal disorders among nursing personnel in korea. int j ind erg 2007;37:207-212. [http://dx.doi.org/10.1016/j.ergon.2006.10.020] 13. hagglund m, walden m, bahr r, ekstrand j. methods for epidemiological study of injuries to professional football players: developing the uefa model. br j sport med 2005;39:340-346. [http://dx.doi.org/10.1136%2fbjsm.2005.018267] 14. livingston la, spaulding sj. measuring of the quadriceps angle using standardized foot positions. j athl training 2002;37:252-255. 15. starke c, ryan fl. evaluation of orthopaedic and athletic injuries. 2nd ed. philadelphia, usa: f a davis company, 2001:288-289. 16. van gent rn, siem d, van middelkoop m, van os ag, bierma-zeinstra sma, koes bw. incidence and determinates of lower extremity running injuries in long distance runners. a systemic review. br j sport med 2007;41:469-480. [http://dx.doi. org/10.1136/bjsm.2006.033548] 17. grelsamer gp, weinstein ch. applied biomechanics of the patella. clin orthop 2001;389:9-14. 18. stergiuo n, bates bt, stanley ls. asynchrony between subtalar and knee joint during running. med sci & sport ex 1999;31(11):1645-1654. 19. mansfield pj, neumann da. essential of kinesiology for the physical therapist’s assistance. mosby: elsevier, 2008:227-268. http://dx.doi.org/10.1136/bjsm.2003.005488] http://dx.doi.org/10.3325/cmj.2007.6.767] http://dx.doi.org/10.1186/1476-5918-7-9] http://dx.doi.org/10.1186/1476-5918-7-9] http://dx.doi.org/10.1016/j.ergon.2006.10.020] http://dx.doi.org/10.1136%2fbjsm.2005.018267] http://dx.doi.org/10.1136/bjsm.2006.033548] http://dx.doi.org/10.1136/bjsm.2006.033548] 1 s af. j sports med vol. 28 no.2 supplement 2016 hosted by sponsors http://utcimaging.com/ http://www.inqababiotec.co.za/ http://www.grootconstantia.co.za/ http://www.sasma.org.za/ 2 s af. j sports med vol. 28 no.2 supplement 2016 contents p1: the effect of load on achilles tendon structure in novice runners .......................................... 4 p2: investigating the role of eln rs2071307 gene variant as a risk factor for achilles tendon pathologies in a british cohort. .......................................................................................................... 4 p3: the effect of substance p and acetylcholine on tenocyte proliferation converge mechanistically via tgf-1 .......................................................................................................................................... 5 p4: tendinosis-like changes in denervated rat achilles tendon ......................................................... 6 p5: glutamate signaling through the nmda receptor reduces the tenocyte phenotype in plantaris tendon cells in vitro and is modulated by loading and glucocorticoids ............................................... 7 p6: glucocorticoids reduce the tenocyte phenotype in primary tendon cells in vitro as seen by decreased expression of scleraxis and collagens .............................................................................. 7 p7: what tendon pathology is seen on imaging in people who have taken fluoroquinolones? a systematic review ............................................................................................................................... 8 p8: the acute effects of mechanical vibration on patellar tendon elasticity as assessed by shear wave elastography ............................................................................................................................. 8 p9: microcirculation in the proximal supraspinatus tendon and correlation to shoulder strength in badminton athletes: with dynamic contrast-enhanced mri ................................................................ 9 p10: correlations between patient-reported outcomes and functional performances in patients with an achilles rupture; construction of the taiwan version of visa-a ........................................ 10 p11: can delivery of mesenchymal stem cell aggregates enhance retention of cells at the site of injury in cell therapy of equine tendon? ............................................................................................ 11 p12: good lumbopelvic stabilization is associated with patellar tendinopathy absence in athletes. 11 p13: is knee valgus associated with patellar tendinopathy in jumping athletes? ............................. 12 p14: is neovascularisation an indicator of subsequent tendon injury risk in horses? ...................... 13 p15: the mechanical properties of scaffolds for rotator cuff repair .................................................. 14 p16: t cell activation profiles in early supraspinatus tendinopathy point towards a th1 phenotype 15 p17: development and optimization of a novel electrospun suture with potential for use in rotator cuff tendon repair .............................................................................................................................. 16 p18: comparison of tgfβ expression in healthy and diseased human tendon .............................. 16 p19: incidence of lower limb tendinopathy in brazilian youth athletes ............................................. 17 p20: effect of iso-inertial squat on incidence of patellar tendinopathy in elite male soccer players 18 p21: temperature differences in affected compared with unaffected legs in subjects with unilateral achilles tendinopathy: a pilot study .................................................................................................. 19 p22: is widespread mechanical sensitivity a feature of achilles tendinopathy? ............................... 20 p24: an investigation into the effect different window size analysis has on achilles tendon ultrasonographic tissue characterisation echo-type quantification. .............................................. 21 p25: an exploration of intron 4 polymorphisms within the col5a1 gene and its association to anterior cruciate ligament injury risk ................................................................................................. 22 p26: investigating an in silico approach to identify genetic susceptibility loci for musculoskeletal soft tissue injuries .................................................................................................................................... 23 p27: the casp8 gene and risk of carpal tunnel syndrome ............................................................. 23 p28: genetic variants in the proteoglycan, decorin and risk of carpal tunnel syndrome. ................. 24 p29: evaluating polymorphisms within the proteoglycan encoding genes with achilles tendinopathy susceptibility ...................................................................................................................................... 25 p30: pieces to the puzzle: identifying variants associated with musculoskeletal soft tissue injuries using whole exome sequencing........................................................................................................ 26 3 s af. j sports med vol. 28 no.2 supplement 2016 p31: tgf-β stimulated bgn gene expression in a genetic susceptibility model for musculoskeletal soft tissue injuries: a pilot ex vivo study. .......................................................................................... 26 p32: more tendinopathy than inflammatory arthritis in a new patient rheumatology clinic. a retrospective review of 397 new patients ......................................................................................... 27 p33: plantaris tendon, its presence, location and size in the region of the achilles tendon: an observational cadaveric study .......................................................................................................... 29 p34: plant derived rhcollagen scaffold combined with prp enhances healing in tendinopathy ..... 29 p35: non-rigid speckle tracking exploratory study for tendinopathy signaling in symptomatic subjects ............................................................................................................................................. 30 p36: cross-sectional pilot study comparing function, morphology and biomechanical behavior of conservatively versus surgically treated achilles tendon ruptures. .................................................. 31 p37: modulation on tendon vascularization is associated with pain in athletes with patella tendinopathy after 12-week of eccentric exercise combined with extracorporeal shockwave therapy .......................................................................................................................................................... 32 p38: a preliminary exploration of somatosensory and psychological characteristics in a severe subgroup of individuals with lateral epicondylalgia ........................................................................... 33 p39: patient characteristics associated with the severity of pain and disability of gluteal tendinopathy ..................................................................................................................................... 33 p40: increase in tendon strain is associated with pain reduction after 12-week eccentric exercises in jumping athletes with patella tendinopathy ................................................................................... 34 p41: taping facilitates scapular kinematics and activity onset of scapular muscles in athletes with rotator cuff tendinopathy ................................................................................................................... 35 4 s af. j sports med vol. 28 no.2 supplement 2016 p1: the effect of load on achilles tendon structure in novice runners lm rabello 1 ; ow heyward 2 ; l van der woude 2 ; i van den akker-scheek; h van der worp 1 ; and j zwerver 1 1 department of sports medicine, university of groningen, groningen, university medical center groningen, , the netherlands, 2 centre for human movement sciences, university medical center groningen, university of groningen, groningen, the netherlands, groningen, the netherlands presenting author e-mail address: l.maciel.rabello@umcg.nl introduction: achilles tendinopathy, characterized by pain and dysfunction, with an incidence estimated between 11% and 29% in runners and 6% in sedentary people. the incidence is higher in athletes but sedentary people are also affected by this condition. there is an association between tendinopathy and load in which repetitive and poorly managed load is assumed to be a major factor in developing tendinopathy due to the tendons negative reaction to a stimulus. different imaging tools are used to assess the effect of load in tendons. ultrasonographic tissue characterization (utc) can quantify tendon structure into four echotypes based upon echo pattern stability. the aim of this study was to observe the changes in achilles tendon structure in novice runners, with loading prescriptions of 100% body weight compared to 20% body weight. methods: a randomized crossover design was employed. 20 novice runners participated in two separate 20 minutes running bouts spaced 14 days apart, one of high load (hl) at 100% body weight on a normal treadmill, and one of low load (ll) at 20% body weight on an alter-g antigravity treadmill. utc was measured on 6 occasions; immediately prior to each run, 2 and 7 days after each run. results: no change was seen in any of the four echotype percentages as a result of the ll or hl running bouts. echotypes iii and iv decreased over time, with a significant effect. the interaction effect of time and condition was not found to be significant for echotypes i-iv [wald chi-square = 2.8, d.f. = 2,p = 0.247; wald chi-square = 2.888, d.f. = 2,p = 0.236; wald chi-square = 1.385, d.f. = 2,p = 0.5; wald chi-square = 4.19, d.f. = 2,p = 0.123], respectively. discussion: the results of this study show that there were no load dependent changes in echotype percentages of novice runners after one moderate or low load running bout. the decrease in echotypes iii and iv suggest that moderate loads can be applied to the achilles tendon without compromising tendon structure. low to moderate loads may be beneficial in the management of achilles tendinopathy. p2: investigating the role of eln rs2071307 gene variant as a risk factor for achilles tendon pathologies in a british cohort. ly el khoury 1,2 , wj ribbans 1 , sm raleigh 1 1 the centre for physical activity and chronic disease, the institute of health and wellbeing, university of northampton, uk; 2 school of biological sciences, university of essex, uk presenting author e-mail address: louis.el-khoury@essex.ac.uk introduction: the harmonious interaction of elastin and other structural proteins allows tendons to respond to tensile load by stretching and returning to their original lengths. achilles tendinopathies and rupture, jointly referred to as achilles tendon pathologies (atps), are polygenic phenotypes with poorly defined aetiologies resulting from either chronic or acute exposure to repetitive and strenuous physical activities. the eln rs2071307 variant has been associated with soft tissue pathologies such as aortic stenosis[1] and aneurysms[2]. the substitution of the hydrophobic amino acid glycine with the hydrophilic serine renders this non-synonymous g/a snp a good candidate variant to investigate. however, in a previous study this variant was not associated with either achilles tendinopathy or acl mailto:louis.el-khoury@essex.ac.uk 5 s af. j sports med vol. 28 no.2 supplement 2016 rupture in populations from australia and south africa[3]. as recent evidence suggests that genetic risk factors for tendinopathy may depend, to some extent, on geographic location[4], the aim of this study was to determine whether the eln rs2071307 variant was associated with the risk of atp in a british cohort. methods: a british caucasian cohort consisting of 108 atp cases (ten n=84 and rup n=24) and 131 asymptomatic controls were recruited for this case-control genetic association study. all participants were genotyped using taqman technology for the eln g/a rs2071307. population data such as genotype and allele frequencies in addition to the hardy-weinberg equilibrium were calculated using the r genetics package. statistical significance was accepted at p<0.05. results: there was no significant genotypic or allelic association between the eln rs2071307 and the risk of ten (p=0.086, p=0.119), rup (p=0.501, p=0.243), or when both pathologies were combined into the atp group (p=0.413, p=0.399) respectively. discussion: although the association of the eln rs2071307 gene variant with soft tissue pathologies is documented in aortic stenosis and aneurysms, it appears not to be associated with the risk of atps in a british caucasian cohort. this data is consistent with the early study in australian and south african cohorts. it should be noted however, that the sample number is small and that these findings require replication in other ethnicities. references: 1. ellis sg, dushman-ellis s, luke mm, et al. pilot candidate gene analysis of patients ≥ 60 years old with aortic stenosis involving a tricuspid aortic valve. am j cardiol 2012;110:88–92. 2. saracini c, bolli p, sticchi e, et al. polymorphisms of genes involved in extracellular matrix remodeling and abdominal aortic aneurysm. j vasc surg 2012;55:171–9.e2. 3. el khoury l, posthumus m, collins m, et al. eln and fbn2 gene variants as risk factors for two sports-related musculoskeletal injuries. int j sports med 2015;36:333–7. 4. el khoury l, ribbans wj, raleigh sm. mmp3 and timp2 gene variants as predisposing factors for achilles tendon pathologies: attempted replication study in a british case–control cohort. meta gene 2016;9:52–5. p3: the effect of substance p and acetylcholine on tenocyte proliferation converge mechanistically via tgf-1 g fong * 1, 2 ; l j backman * 1 ; p danielson 1 *co-first author 1 department of integrative medical biology, anatomy, umeå university, umeå, sweden 2 centre for hip health and mobility, vancouver coastal health and research institute, british columbia, canada presenting author e-mail address: gloria.fong@umu.se introduction: previous in-vitro studies on tenocytes have demonstrated that exogenous administration of substance p (sp) and acetylcholine (ach) independently result in proliferation which is a prominent feature of tendinosis. interestingly, the link between sp and ach have not yet been explored. studies demonstrate that both sp and ach independently upregulate tgf-1 expression via their respective receptors, neurokinin 1 receptor (nk-1r) and muscarinic ach receptors (machrs). 1,2 furthermore, tgf-1 has been shown to downregulate nk-1r expression. 3 consequently, it can be hypothesized that tgf-1 is the intermediary player involved in mediating the pathways shared by sp and ach in human tenocytes. in the present study, we examined if the known proliferative effects of sp and ach converged via tgf-1. methods: human achilles tendon cells (tenocytes) were cultured and exposed to exogenous sp, ach, and tgf-1, along with their respective receptor blockers. the mrna and protein levels for nk1r, machrs, and tgf-1 were measured using rt-qpcr, western blot, and elisa. proliferation was measured using mts and crystal violet assays. mailto:gloriahfong@gmail.com 6 s af. j sports med vol. 28 no.2 supplement 2016 results: exogenous administration of sp and ach both resulted in upregulation of tgf-1 at the mrna and protein level. in addition, exogenous tgf-1 downregulated both nk-1r and machrs expression at the mrna and protein level. furthermore, this effect was negated by the tgfri/ii kinase inhibitor. finally, exogenous administration of tgf-1 resulted in increased cell viability, which was effectively blocked in the presence of tgfri/ii kinase inhibitor. discussion: based on the results, we propose that tgf-1 is the intermediary player through which the actions of both sp and ach converge mechanistically. in this study, the exposure of tenocytes to sp and ach resulted in upregulation of tgf-1. tgf-1, in turn, decreased the expression of nk-1r and machrs, suggesting a negative feedback loop. in tendinosis, it is plausible that this feedback mechanism becomes aberrant, thus resulting in a persistently high expression of tgf-1, a potent activator of tenocyte proliferation, that leads to hypercellularity in the tendon tissue, a cardinal feature of tendinosis. references: 1. yang et al 2014 2. jin et al 2015 3. le roux et al 2015 p4: tendinosis-like changes in denervated rat achilles tendon roine el-habta 1 ; ludvig j. backman 1 1 department of integrative medical biology, umeå university, umeå, sweden presenting author e-mail address: roine.el-habta@umu.se introduction: tendinosis is characterized by several histopathological changes such as hypercellularity, inadequate repair (i.e. disrupted collagen synthesis), and angiogenesis. previous studies have linked these changes to increased levels of neuropeptide substance p (sp), and its preferred receptor neurokinin-1 (nk-1r). when it comes to the histopathological changes and the possible involvement of sp and nk-1r in denervated tendons, little is known. in this study we examined denervated rat achilles tendons two weeks after peripheral nerve injury. methods: rats that had been denervated for two weeks were sacrificed and the achilles tendons were collected. tendons were divided into two pieces, one for immunohistochemical staining, and one for homogenization and extraction of mrna. tendons were sectioned using a microtome and immunostained for nk-1r as well as hematoxylin and eosin for morphological examination and cell counting. for qpcr we used hydrolysis probes to detect the expression of tac1, tacr1, collagen i, and collagen iii. results: preliminary results show that denervated tendons contain more and presumably larger cells as compared to the control (contra-lateral leg) (p<0.05). no obvious architectural disturbances in the collagen arrangement could be observed but qpcr results revealed highly altered collagen iii and collagen i mrna levels (p<0.01, and p<0.001, respectively). immunohistochemical staining indicated increased expression of nk-1r, and the mrna expression of tacr1 and tac1 was significantly upregulated as compared to the control (p<0.05, and p<0.01, respectively). discussion: in this study we confirmed that denervated tendons share many common features with tendinosis, such as hypercellularity, increased levels of sp and nk-1r, as well as disrupted collagen synthesis. our data stress; (1) that a denervated tendon should be treated as tendinosis once the muscle is re-innervated; (2) that modulation of neuropeptides might preserve a denervated tendon. 7 s af. j sports med vol. 28 no.2 supplement 2016 p5: glutamate signaling through the nmda receptor reduces the tenocyte phenotype in plantaris tendon cells in vitro and is modulated by loading and glucocorticoids c spang 1 ; l backman 1 ; j chen 1 ; le roux s 1 ; and p danielson 1 1 department of integrative medical biology, anatomy section, umeå university, sweden presenting author e-mail address: ludvig.backman@umu.se introduction: it has been speculated that signalling substance glutamate may be involved in the process of tendinosis e.g. as an apoptosis inducing substance. in this study, the potential impact of glutamate was further analysed by studying the effect on the tenocyte phenotype. additionally, the effect of loading and exposure to glucocorticoids on the glutamate signalling machinery was evaluated. methods: tendon specimens used were derived from plantaris tendons. tendon tissue and cultured primary tendon cells were immunohisto-/cytochemically stained using antibodies against glutamate, nmda receptor subunit 1 (nmdar1), the phosphorylated nmdar1 and vesicular glutamate transporter vglut2. tendon cells were further exposed to glutamate or the receptor agonist nmda for up to 72 hours in concentrations up to 10 mm. the effect on cell death and cell viability was measured via ldh and mts assays. western blots were used for detecting c-caspase 3 and c-parp protein. scleraxis gene expression (scx) and protein (scx) were analysed by qpcr and western blot, respectively. via a flexcell system cyclic strain was applied to the cells. the effect of glucocorticoid dexamethasone (dex) was studies. the mrna of the glutamate synthesizing enzymes got1 and gls, and nmdar1 protein was measured as a response to cyclic strain and dex exposure. results: immunoreactions for glutamate, nmdar1, pnmdar1 and vglut2 were detected in tenocytes and peritendinous cells in tissue sections as well as in cultured primary tendon cells. cell death was induced by a high dose of glutamate (10 mm) but not via exposure of nmda. scleraxis mrna/protein was down-regulated in response to nmda stimulation. cyclic strain increased, and dexamethasone decreased, gls and got1 gene expression. the amount of nmdar1 protein expression was increased after 3 days of loading but not affected by dexamethasone exposure. discussion: in conclusion, nmda receptor stimulation leads to a phenotype drift in primary plantaris tendon cells. furthermore, glutamate synthesis is increased in tendon cells in response to strain. glucocorticoid stimulation decreased glutamate production. these results imply that locally produced glutamate could be involved in the tissue degeneration observed in tendinosis in response to chronic tendon load. p6: glucocorticoids reduce the tenocyte phenotype in primary tendon cells in vitro as seen by decreased expression of scleraxis and collagens c spang 1 ; j chen 1 ; l j backman 1 1 department of integrative medical biology, anatomy section, umeå university, sweden presenting author e-mail address: ludvig.backman@umu.se introduction: treating tendinopathies with glucocorticoids has recently been questioned. several clinical papers have reported higher risks for ruptures and in vitro studies have observed glucocorticoid-induced reduction of cell viability and collagen i production in tenocytes. however, little is known about the effect of glucocorticoids on the tendon-specific characteristics of tenocytes. furthermore, there are uncertainties about the occurence of apoptosis and if the reduction of collagen affects all collagen subtypes similarly. methods: to investigate these aspects we cultured primary tendon cells from tissues specimens derived from plantaris tendons. cells were exposed to glucocorticoid dexamethasone (dex) in concentrations ranging from 1-1000 nm for up to 5 days. the gene expression of the specific tenocyte 8 s af. j sports med vol. 28 no.2 supplement 2016 markers scleraxis (scx) and tenomodulin (tmnd) and markers indicating other mesenchymal lineages, such as cartilage (acan, col2, sox9), bone (alpl, ocn), and fat (cebpα, pparg) was analysed via qpcr. cell proliferation and viability was measured by the use of a mts assay. cell death was detected by ldh assays and by the presence of cleaved caspase-3 protein using western blot. furthermore, gene expression of collagen subtypes col1, col3 and col14 was measured. results: dex exposure decreased cell viability (mts) and ldh levels in a dose-dependent manner. it also induced a significant reduction of scx gene expression and a marked loss of fibroblast like cell shape. all examined collagen subtypes were found to be down-regulated. among non-tendinous genes from other mesenchymal lineages pparg was significantly increased, acan, alpl and sox9 were significantly decreased. discussion: the results of this study suggest that dex causes a phenotype drift of the tenocytes via decreased scleraxis expression. reduction of several collagen subtypes but not apoptosis seem to be a characteristics of the use of dex on tendon tissue. altogether this study provides further evidence for glucocorticoid induced tendon tissue degeneration. p7: what tendon pathology is seen on imaging in people who have taken fluoroquinolones? a systematic review tr lang 1 ; j cook 2 ; e rio 2 ; j gaida 3 and s docking 2 1 school of primary health care, monash university, melbourne, australia, 2 la trobe centre for sports and exercise medicine research, la trobe university melbourne, australia, 3 university of canberra research institute for sport and exercise (ucrise), canberra, australia presenting author e-mail address: jamie.gaida@canberra.edu.au introduction: fluoroquinolones (fqs) are highly effective broad spectrum antibiotics. clinical data reveal an increased incidence of tendon pain and rupture in those taking fqs, yet little is known about tendon structural changes. this review synthesises published data on tendon structural changes in people who have taken fqs. methods: eight databases were searched for potentially relevant articles (medline, cinahl, biological abstracts, amed, web of knowledge, scopus, sportdiscus and embase) using mesh and free-text searches. inclusion and exclusion criteria determined which articles were used for this review. results: twenty-six papers met the eligibility criteria. the achilles tendon was most commonly affected, while ciprofloxacin and levofloxacin were the most commonly implicated fqs. mean time to onset of symptoms was sixteen days following first fq dose. imaging modalities used included mri, b-mode ultrasound, and ct. tendon measurements were rarely reported and intra-tendinous imaging findings were not reported in a consistent manner. few studies imaged tendons bilaterally and only two studies were longitudinal in design. discussion: future studies should report imaging measures such as thickness and cross-sectional area, and use consistent descriptions of intra-tendinous changes during and post fq treatment. p8: the acute effects of mechanical vibration on patellar tendon elasticity as assessed by shear wave elastography wei-chen peng 1 , yi-ping chang 2 , and hsing-kuo wang 1, 2 9 s af. j sports med vol. 28 no.2 supplement 2016 1 school and graduate institute of physical therapy, college of medicine, national taiwan university, taipei, taiwan, r.o.c., 2 physical therapy center, national taiwan university hospital, taipei, taiwan, r.o.c. e-mail address of presenting author: r03428006@ntu.edu.tw introduction: previous studies showed increased tendon elastic modulus (em) in patients with patellar tendinopathy. zhang et al. also found that em positively correlates with pressure pain and negatively correlates with the patient’s victorian institute of sport assessment-patella (visa-p) score. it seems clinically beneficial to reduce the em in rehabilitation for patellar tendinopathy. the aim of this study was to investigate the effects of mechanical vibrations on the em by using shear wave elastography (swe) of the patellar tendon. methods: fifteen healthy adults (median age: 25 years; age range: 22-26 years) were recruited and, for each participant, a mechanical vibration intervention was applied perpendicular to the mid-portion of the right patellar tendon under knee flexion of 90˚ for 10 minutes. swe, a newly introduced ultrasound-based technique, was used to measure the shear wave velocity (swv) of the patellar tendon before and immediately after the mechanical vibration, under knee flexions of both 60˚ and 90˚. the wilcoxon sign ranked test was used for statistical analysis. to evaluate the intra-operator reliability of the measurements of patellar tendon elasticity, seven of the fifteen subjects had their second measurements under both 60˚ and 90˚ of knee flexion taken within 7 days by the same operator. results: for knee flexions of both 60˚ and 90˚, the swv (p= 0.003, 0.004) was significantly decreased after the 10-minute intervention of mechanical vibration. the mean values of swv for all the 15 participants decreased from 6.34±0.87 (m/s) to 5.39±1.12 (m/s) for the 60˚ flexion, and from 8.80±0.91 (m/s) to 8.00±1.24 (m/s) for the 90˚ flexion. also, the measurements for both knee flexions had good intra-operator reliability, with an intraclass correlation coefficient (icc) of 0.902 (95% confidence interval [ci]: 0.428-0.983) and 0.860 (95% ci: 0.185-0.976), respectively. conclusion: the elasticity of the patellar tendon decreased after the mechanical vibration intervention was applied, suggesting that such vibration might have beneficial effects in clinical applications to restore tendon elasticity. references 1. hsiao my, chen yc, lin cy, chen ws, wang tg. reduced patellar tendon elasticity with aging: in vivo assessment by shear wave elastography. ultrasound med biol 2015;41:2899-905. 2. zhang zj, fu sn. shear elastic modulus on patellar tendon captured from supersonic shear imaging: correlation with tangent traction modulus computed from material testing system and test-retest reliability. plos one 2013;8:e68216. 3. zhang zj, ng gy, lee wc, fu sn. changes in morphological and elastic properties of patellar tendon in athletes with unilateral patellar tendinopathy and their relationships with pain and functional disability. plos one 2014;9:e108337. p9: microcirculation in the proximal supraspinatus tendon and correlation to shoulder strength in badminton athletes: with dynamic contrast-enhanced mri hsing-kuo wang 1 , chih-wei yu 2 , chao-yu hsu 2 , bang-bin chen 2 , hsin-chia chen 2 , tiffany ting-fang shih 2 1 school and graduate institute of physical therapy, college of medicine, national taiwan university; center of physical therapy, national taiwan university hospital, taiwan, roc. 2 department of radiology and medical imaging, national taiwan university college of medicine and hospital, taiwan, roc. presenting author e-mail address: hkwang@ntu.edu.tw 10 s af. j sports med vol. 28 no.2 supplement 2016 introduction: to measured the features of dynamic contrast-enhanced magnetic resonance imaging (dce-mri) in the anterior and posterior portions of the supraspinatus tendon at the myotendinous junction, as well as the whole tendon, and investigated the correlations between the features and performances of shoulder performance in college overhead athletes. methods: seventeen qualified badminton athletes were recruited. dce-mri was conducted on the tendons in each athlete’s dominant arm, including measures for the volume transfer constant (k trans ), the extravascular extracellular space volume (ve) and the plasma volume (vp) per unit volume of tissue. the shoulder isokinetic tests were used to measure the acceleration time and the relative fatigue ratio of the shoulder external rotation of the arm. results: the dce-mri (median; k trans , kep, ve and vp) for the anterior (0.031, 0.198, 18.04 and 0.31 respectively), posterior (0.067, 0.468, 18. 50 and 0.25), and entirety of the tendon (0.050, 0.325, 20.76 and 0.60) showed regional differences and correlations between the kep value for the whole supraspinatus tendon and the acceleration time (r =-0.663, p = 0.005), between the vp values for the whole tendon and relative fatigue ratio (r =-0.605, p = 0.01). median values of the acceleration time and relative fatigue ratio were 890.0 ms and 31.8% respectively. conclusions: there are differences of microcirculatory features between the anterior and posterior portion supraspinatus tendon, and also associations between the feature of the supraspinatus tendon and muscle performances. intratendinous microcirculatory features at the myotendinous junction may vary with tendon morphomechanical adaptation to loadings. p10: correlations between patient-reported outcomes and functional performances in patients with an achilles rupture; construction of the taiwan version of visa-a yp chang 1 ; wc pong 2 ; and hk wang 1,2 1 physical therapy center, national taiwan university hospital, taipei, taiwan, roc, 2 school and graduate institute of physical therapy, college of medicine, national taiwan university, taipei, taiwan. presenting author e-mail address: r01428012@ntu.edu.tw introduction: the purposes of the study were to construct the taiwan chinese version of the victorian institute of sport assessment scale-achilles (visa-a) questionnaire (visa-a-tc) for outcomes of subjects with an achilles tendon rupture between 3 and 6 months postsurgery, to establish the questionnaire’s validity and reliability, and to assess the correlations between the visaa-tc and functional performance in such subjects. methods: fifteen subjects (13 males, 2 females; age, median: 44.6 years; range: 38.1 51.0 years) were recruited. three subjects participated in a nine-step procedure to translate and adapt the visaa questionnaire into the visa-a-tc. the other 12 subjects participated in tests to assess the testretest reliability and validity of the visa-a-tc, as well as three functional tests: the heel-raise test, star excursion balance test (sebt) and one-leg hopping test. results: the visa-a-tc showed good test-retest reliability (icc=0.992) and internal consistency (cronbach's alpha= 0.711 and 0.762, respectively, for the 1 st and 2 nd visa-a-tc surveys). the visaa-tc was moderately correlated with the lower extremity functional scale, with concurrent validities for the 1 st and 2 nd visa-a-tc surveys of rho= 0.697 and 0.680. the visa-a-tc showed negative correlations with the differences between the un-injured and injured legs for the sebt score and hopping distance (rho ranged between -0.655 and -0.671). discussion: the results indicate that the visa-a-tc is appropriate for use by chinese patients with an achilles repair after rupture. in addition, self-reported physical functional limitations among these patients were associated with physical impairments that can be partially identified by simple physical tests. 11 s af. j sports med vol. 28 no.2 supplement 2016 references: 1. robinson jm, cook jl, purdam c, visentini pj, ross j, maffulli n, et al. the visa-a questionnaire: a valid and reliable index of the clinical severity of achilles tendinopathy. br j sports med 2001;35:335-41. p11: can delivery of mesenchymal stem cell aggregates enhance retention of cells at the site of injury in cell therapy of equine tendon? y kasashima 1 ; n tamura 1 ; y kotoyori 2 ; k fukuda 1 ; t kuroda 1 and y tabata 3 1 clinical science & pathobiology division, equine research institute, japan racing association (jra), japan; 2 race horse hospital, ritto training center, jra, japan; 3 department of biomaterials, institute for frontier medical sciences, kyoto university, japan. presenting author e-mail address: kasashima@equinst.go.jp introduction: cell therapy using cultured mesenchymal stem cells (mscs) is now a popular treatment for equine tendon injury. a major challenge to the success of the technology may be improving retention of cells at the site of injury as several studies have reported considerable cell loss post implantation [1]. in this study, the use of gelatin microspheres (gms), which provide an injectable cell delivery vehicle without loss of cell attachment sites was explored [2]. we performed a tracking study of mscs as cell aggregates compared to cells alone transplanted into a surgically induced lesion of sdft. methods: the cell aggregates containing fluorescent-labelled mscs (10 7 ) and gms were used after incubation for 7 days and then injected into the left limb. similarly labelled mscs (10 7 ) recovered as a cell suspension from culture flask by trypsin were injected into the right limb. superficial digitorum flexor tendons (sdfts) were harvested at 7 and 14 days (each n=1) and at 30 days (n=2) after transplantation and sections of the injury site were examined under a fluorescence microscope. results: the aggregates of labelled mscs were observed in the lesion and a low fluorescence signal was observed within the endotenon at 7 days post transplantation. migration of a few mscs to areas adjacent to the aggregates was observed. degradation of gms was seen at 14 days. while, mscs transplanted as single cell suspensions were located mainly within the endotenon with only small numbers present within the tendon fascicles at 7 days. at 30 days, similar results were seen in decreased fluorescence signal in the endotenon for both methods of cell delivery. discussion: cell aggregates enhanced retention of mscs in the lesion area for a longer time period than conventional single cell suspension. initially the aggregates delivered cells within the tendon more effectively than cells alone. however, the viability and presence at the injury site of the mscs 30 days post implantation was similar for both methods. since gms can deliver both cells as well as biomolecules simultaneously, further research is needed to explore this delivery method to combine cells and other active molecules with potential to enhance regeneration of the tendon. references 1. guest et al, equine vet j, 42(7): 636-642, 2010 2. hayashi et al, acta biomaterialia, 7(7):2797-2803, 2011 p12: good lumbopelvic stabilization is associated with patellar tendinopathy absence in athletes. luciana de michelis mendonça 1,2 , natália fn bittencourt 1,3 , juliana m ocarino 4 , sérgio t. fonseca 1,4 . 1 laboratório de prevenção e reabilitação de lesões esportivas universidade federal de minas gerais mg – brasil; 2 departamento de fisioterapia fcbs universidade federal 12 s af. j sports med vol. 28 no.2 supplement 2016 dos vales do jequitinhonha e mucuri mg – brasil; 3 nice minas tenis clube mg – brasil; 4 departamento de fisioterapia eeffto universidade federal de minas gerais mg brasil presenting author e-mail address: lucianademichelis@yahoo.com.br introduction: some knee injuries are predicted by neuromuscular control of the trunk 1 . the bridge test with unilateral knee extension is used to assess pelvic girdle stability, which is important for injury prevention and performance 2 . however the relationship between the bridge test and patellar tendinopathy (pt) has not been explored. the purpose of this study was to investigate the association between effective performance of the bridge test and patellar tendinopathy in athletes. methods: one-hundred and twenty-five athletes, forty-two female and 83 male, from volleyball (n = 74) and basketball (n = 51) were evaluated. the sample had a mean age of 18.78 ± 5.5 years, mean height of 1, 78 ± 0.34 metres and mean body mass of 75.13 ± 15.18 kilograms. they were asked to perform three repetitions of the bridge test with unilateral knee extension with each lower limb. quantitative analysis was performed by measuring the highest transverse plane pelvic drop angle in each repetition performed to allow the mean extraction from the three measurements collected on each lower limb. pt severity was determined by visa-p questionnaire score (value bellow 80 points). classification and regression tree (cart) was used to identify the bridge test parameters associated to pt presence and absence. results: the mean of transverse plane pelvic drop angle was 11.02 o (sd=5.1 o ) with support of the dominant lower limb and 11.52 o (sd=5.7 o ) with support of the non-dominant lower limb on the treatment table. cart model was accurate (p=0.017; area under the curve=62.5%) and showed a better prediction for pt absence. athletes without pt showed transverse plane pelvic drop angle under 5.75 o on the dominant lower limb (n=14) or asymmetry between lower limbs under 9.2 o (n= 57). conclusion: the results showed that a good transverse plane pelvic control was associated with pt absence. interestingly, different parameters of pelvic drop (absolute values and asymmetries) were necessary to enhance the cart model accuracy. it is recommended that bilateral assessment of the bridge test in athletes with unilateral pt is performed. keywords: stability, sport, injury, knee. acknowledgement: fundação de amparo a pesquisa do estado de minas gerais (fapemig), coordenação de aperfeiçoamento de pessoal de nível superior (capes) and conselho nacional de desenvolvimento científico e tecnológico (cnpq). references: 1. zazulak bt, hewett te, reeves p, goldberg b, cholewicki j. deficits in neuromuscular control of the trunk predict knee injury risk: a prospective biomechanical-epidemiologic study. am. j. sports med. 2007; 35; 1123. 2. santos tr, andrade ja, silva bl, garcia af, persichini filho jg, ocarino jde m, silva pl. (2014). active control stabilization of pelvic position in the transverse plane: an evaluation of soccer players' performance. physical therapy in sport,15(3), 189-193. p13: is knee valgus associated with patellar tendinopathy in jumping athletes? luciana de michelis mendonça 1,2 , natália fn bittencourt 1,3 , juliana m ocarino 4 , sérgio t. fonseca 1,4 . 1 laboratório de prevenção e reabilitação de lesões esportivas universidade federal de minas gerais mg – brasil; 2 departamento de fisioterapia fcbs universidade federal dos vales do jequitinhonha e mucuri mg – brasil; 3 nice minas tenis clube mg – brasil; 4 departamento de fisioterapia eeffto universidade federal de minas gerais mg brasil mailto:lucianademichelis@yahoo.com.br 13 s af. j sports med vol. 28 no.2 supplement 2016 presenting author e-mail address: lucianademichelis@yahoo.com.br introduction: literature shows that knee valgus is associated with anterior cruciate ligament injury and patellofemoral pain, however, the relationship between knee valgus and pt has never been investigated. 1 knee valgus could impose rotational forces on the patellar tendon and overload the tissue asymmetrically. several studies use the victorian institute of sport assessment scale (visa-p) questionnaire to clinically identify individuals with patellar tendinopathy (pt) 2 . visa-p is a questionnaire adapted and validated for the brazilian population, which quantifies patellar tendon pain and functional disability. the purpose of this study was to investigate the association of patellar tendinopathy and frontal plane knee projection angle in athletes. methods: athletes assessed preseason, including single-leg decline squat bidimensional analysis, were invited to participate and signed a consent form. inclusion criteria included participating regularly in sports team activities. the visa-p score used to identify athletes with pt was 80 points. fifty-eight female and 165 male (n = 223) athletes participated in this study with a mean age of 17.79 (sd = 4.7) years, body mass of 76.00 (sd = 13.7) kilograms and height of 1.85 (sd = 00.11) metres. forty-four athletes participated in basketball and 135 in volleyball with a mean frontal plane knee projection angle of 6.87 o (sd=4.4 o ) on dominant lower limb and 6.15 o (sd=4.2 o ) on the non-dominant lower limb. descriptive statistics were used to characterize the sample and visa-p questionnaire profile. prevalence ratio (pr) and confidence intervals (ci) were calculated to assess the association of visa-p questionnaire score and frontal plane knee projection angle on the injured lower limb. results: the mean score of visa-p questionnaire was 89.44 (sd = 13.79) and 44 athletes (19.73%) scored below 80 points. there was no association of visa-p questionnaire score and frontal plane knee projection angle, pr = 1.24 (ci = 0.83-1.86). conclusion: the results showed that knee valgus was not associated with pt in volleyball and basketball athletes. probably for pt the injury mechanism is more related to jumping demand associated with low knee flexion on landing. acknowledgement: fundação de amparo a pesquisa do estado de minas gerais (fapemig), coordenação de aperfeiçoamento de pessoal de nível superior (capes) and conselho nacional de desenvolvimento científico e tecnológico (cnpq). references: 1. munro a, herrington l, comfort p. comparison of landing knee valgus angle between female basketball and football athletes: possible implications for anterior cruciate ligament and patellofemoral joint injury rates. physical therapy in sport 13 (2012) 259e264. 2. visentini pj, khan km, cook jl, kiss zs, harcourt pr, wark jd. (1998). the visa score: an index of severity of symptoms in patients with jumper's knee (patellar tendinosis). journal of science and medicine in sport, 1(1), 22-28. p14: is neovascularisation an indicator of subsequent tendon injury risk in horses? n tamura 1 ; e yoshihara 2 ; k kodaira 3 ; t kuroda 1 ; k fukuda 1 ; and y kasashima 1 1 clinical science & pathobiology division, equine research institute, japan racing association (jra), japan; 2 race horse hospital, ritto training centre, jra, japan; 3 race horse hospital, miho training centre, jra, japan. presenting author e-mail address: tamura@equinst.go.jp introduction: neovascularisation detected using power doppler ultrasonography (pdu) is often observed in examination for tendinopathy (even in routine scans of clinically asymptomatic tendons). however, the exact role of neovascularisation remains an issue of contention. the potential value of neovascularisation as a prognostic indicator of injury is not clear [1]. mailto:lucianademichelis@yahoo.com.br 14 s af. j sports med vol. 28 no.2 supplement 2016 the aim of this study was to test the hypothesis that the risk of tendon injury in racehorses with tendon neovascularisation-positive (np) is higher than those with neovascularisation-negative (nn). we also evaluated the association between the risk of tendon injury and the length of rest periods in racehorses, from initial pdu (baseline) to the next race start. methods: a prospective cohort study of 98 racehorses with slight peritendinitis determined by clinical conditions but not overt superficial digital flexor tendon (sdft) injury at baseline was conducted. the presence of neovascularisation in sdft was defined as positive signal depicted with pdu at baseline. a subsequent sdft injury was defined as diagnosis by veterinarians with grey-scale ultrasonography. rest period was calculated from the official record. hazard ratios (hr) comparing hazard of sdft injury were calculated using cox proportional hazards regression. results: the np group comprised 43 racehorses (43.9%). the rates of sdft injury in the nn and np groups were 2.50 and 5.21 injuries/100 horse-months, respectively. the hazard in np group was significantly greater (hr 2.38, 95% ci 1.15-5.20, p = 0.023). in subpopulation analysis of the np group, the rates of sdft injury in racehorses within 100 days rest periods and it with over 100 days were 2.10 and 7.21 injuries/100 horse-months, respectively. the hazard in the racehorses with over 100 days rest periods was significantly lower (hr 0.32, 0.07-0.95, p = 0.039). this significant difference was not observed in the nn group. discussion: there was a significant positive relation between the presence of neovascularisation inside the tendon and subsequent sdft injury. this study suggested that an increasing neovascularisation inside the tendon would be an important prognostic indicator of tendon injury, and that the risk may decrease by observingan appropriate rest period following identification of neovascularisation. references 1. mahieu et al, br j sports med, 48:a38, 2014 p15: the mechanical properties of scaffolds for rotator cuff repair rdj smith 1 , n zargar 1 , cp brown 1 , ns nagra 1 , sg dakin 1 , sj snelling 1 , o hakimi 1 , a carr 1 1 nuffield department of orthopaedics, rheumatology and musculoskeletal sciences, university of oxford, old road, oxford, ox3 7ld, uk. presenting author e-mail address: stephanie.dakin@ndorms.ox.ac.uk introduction: re-tearing following rotator cuff surgery is a major clinical problem. numerous scaffolds are being used to try and reduce re-tear rates, however, few have demonstrated clinical efficacy. we hypothesise that this lack of efficacy is due to deficiency in their mechanical properties. we therefore compared the macro and nano/micro mechanical properties of 7 commercially available scaffolds to those of the healthy human supraspinatus tendons, whose function they seek to restore. methods: the clinically approved scaffolds tested were x-repair, lars ligament, poly-tape, biofiber, graftjacket, permacol, and conexa. fresh-frozen cadaveric human supraspinatus tendon samples were used as a comparator. five samples of each material were used per experiment. macro mechanical properties were determined through tensile testing (deben stage), suture pull out (zwick machine) and rheometry (rheometer). scanning probe microscopy and scanning electron microscopy were performed to assess the morphology, young’s modulus, and loss tangent of materials at the nano/micro scale. results: none of the scaffolds tested adequately approximated both the macro and micro mechanical properties of healthy human supraspinatus tendon. macroscale mechanical properties were insufficient to restore load-bearing function. x-repair, (p≤0.001), lars ligament (p≤0.01), and polytape (p≤0.05) experienced tensile failure at forces significantly higher than all other scaffolds. xrepair (p≤0.001) had the greatest suture-retention of all scaffolds tested. however, these synthetic scaffolds had nano/microscale properties that were significantly different to native supraspinatus 15 s af. j sports med vol. 28 no.2 supplement 2016 tendon. scaffolds approximating tendon properties on the nano/microscale, including graftjacket, permacol, conexa, and biofiber had poor macroscale properties. discussion: our results suggest that generic scaffolds require modification to restore mechanical function across hierarchical levels. we recommend biological scaffolds be supplemented with a higher-strength, suture-friendly material in order to provide adequate mechanical response when applied to rotator cuff repair. by determining the mechanical properties of each scaffold relative to native tissue, this study can help surgeons determine the scaffold most appropriate for clinical use. p16: t cell activation profiles in early supraspinatus tendinopathy point towards a th1 phenotype sg dakin 1 ; r hedley 1 ; mh al-mossawi 1 ; s kiriakidis 1 ; p taylor 1 ; k wheway 1 ; b watkins 1 ; aj carr 1 1 botnar research centre, nuffield department of orthopaedics, rheumatology and musculoskeletal sciences, university of oxford, united kingdom. presenting author e-mail address: stephanie.dakin@ndorms.ox.ac.uk introduction: there is a growing body of evidence to support the contribution of inflammation to the onset and progression of tendinopathy. whilst immune cells such as t cells have been identified in diseased human tendons (1, 2), little is known of their phenotype or the pro-inflammatory mediators they potentially release. in this study, we investigate the activation profiles of t cells in samples of early stage diseased human supraspinatus tendons and their capacity to release pro-inflammatory cytokines. methods: tendon biopsies were collected from patients with early stage supraspinatus tendinopathy (4 females, 2 males, aged between 27-71 years) under general anaesthesia prior to surgical subacromial decompression treatment. to investigate t cell phenotype, samples were digested and stained using a validated panel of t cell surface markers for th1, th2, treg and th17 activation. to investigate the capacity of activated t cells to release ifn, tnf and il17a, tissue digests were stimulated with pma (50ngml -1 ) and iomomycin (1gml -1 ) for 4 hours at 37c and stained with a validated flow cytometry t cell effector panel. isotype and unstained controls were run on peripheral blood mononuclear cells isolated from blood cones. samples were run on a fortessa flow cytometer and analysed using flowjo software. results: cd45+ cells accounted for up to 23% of viable cells in tendon tissue digests (mean 7.6%, sem 3.5%). of the cd45+ cells, between 30-63% were cd3+ (mean 48%, sem 4.6%). cd4 + and cd8 + t cells expressed cxcr3, suggestive of a th1 activation signature. markers for regulatory t cells and th17 activation showed only low level expression, markers of th2 activation were not expressed. ifn and tnf were produced by cd4+ and cd8+ t cells in response to stimulation of tissue digests with pma and ionomycin, il17a was not detected. discussion: the findings from this study suggest t cells have a th1 activation profile in early stage supraspinatus tendinopathy. t cells in these samples have the capacity to release pro-inflammatory cytokines including ifn and tnf. we propose this lymphoid population is likely an important contributor to the inflammatory phenotype frequently seen in samples of early stage supraspinatus tendinopathy. acknowledgements: this work was funded by arthritis research uk grant 20506 and the nihr oxford musculoskeletal biomedical research unit. references: 1. m. s. kragsnaes, u. fredberg, k. stribolt, s. g. kjaer, k. bendix, t. ellingsen, stereological quantification of immune-competent cells in baseline biopsy specimens from achilles tendons: results from patients with chronic tendinopathy followed for more than 4 years. am j sports med 42, 24352445 (2014). 16 s af. j sports med vol. 28 no.2 supplement 2016 2. n. l. millar, a. j. hueber, j. h. reilly, y. xu, u. g. fazzi, g. a. murrell, i. b. mcinnes, inflammation is present in early human tendinopathy. am j sports med 38, 2085-2091 (2010). p17: development and optimization of a novel electrospun suture with potential for use in rotator cuff tendon repair re abhari 1 , pa mouthuy 1 , n zargar 1 , a carr 1 1 nihr biomedical research unit, nuffield department of orthopaedics, rheumatology and musculoskeletal sciences, botnar research centre, university of oxford, ox3 7ld, uk presenting author e-mail address: roxanna.abhari@ndorms.ox.ac.uk introduction: rotator cuff repairs often fail at the tendon-suture interface. pull through of the suture through tissue is common, because the material characteristics are often not suitable to support the repair of the weak tendon. novel sutures that mimic tendon architecture may improve patient outcomes. recent in vivo data has shown that submicron electrospun fibres promote better attachment, growth and orientation of cells 1 . this work describes production of an electrospun suture with high tensile strength and relevant degradation rate for tendon healing. methods: a custom electrospinning setup with a single nozzle and stainless steel wire collector was designed to fabricate continuous filaments with different weight/volume ratios of polydioxanone (pdo). the filaments were stretched and annealed, or heat-treated, at various times and temperatures. in vitro degradation testing in pbs was done and samples characterized by tensile and material testing (scanning electron microscopy and differential scanning calorimetry) for up to 6 weeks. results: a 9% weight/volume ratio of pdo solution produced mechanically strong filaments made up of aligned fibres with a diameter around 1um. annealing for longer than 6 hours significantly decreased the strain (p < 0.0001) and above 75˚c always weakened the material (p < 0.0001). annealing for 3 hours at 65˚c was chosen, as only 15% and 34% of its strength and strain was lost, respectively, over a 6-week degradation period. material testing indicated that these parameters led to a rearrangement of polymer crystalline regions, resulting in a more stable structure over time. discussion: this study examined important steps in the suture manufacturing process. we were able to produce electrospun filaments with fibres on a submicron scale and determine optimal annealing parameters. our analysis of the material changes that occur during degradation will be useful for future efforts to tailor the mechanical properties to the functional demands of diseased tendon tissue. this work is relevant to the development of a biomimetic, absorbable suture with high tensile strength retention for use in tendon repair. references: 1. mouthuy p-a, zargar n, hakimi o, lostis e, carr a. fabrication of continuous electrospun filaments with potential for use as medical fibres. biofabrication. 2015;7(2):25006. p18: comparison of tgfβ expression in healthy and diseased human tendon henry cj goodier 1,2 , andrew j carr 1,2 , sarah jb snelling 1,2 , lucy roche 1,2 , kim wheway 1,2 , bridget watkins 1,2 and stephanie g dakin 1,2 1 botnar research centre, nuffield department of orthopaedics, rheumatology and musculoskeletal sciences, university of oxford, nuffield orthopaedic centre, windmill 17 s af. j sports med vol. 28 no.2 supplement 2016 road, headington ox3 7ld, uk; 2 nihr oxford biomedical research unit, botnar research centre, university of oxford, windmill road, oxford ox3 7ld, uk presenting author email address: hgoodier@gmail.com introduction: rotator cuff disease is a common cause of shoulder pain. diseased tendons are characterised by fibrotic scar tissue, which adversely affects tendon structure and function and increases the likelihood of re-injury. inflammation-mediated fibrosis is well documented in skin, liver, renal and pulmonary fibrotic diseases. however, little is known about the mechanisms by which fibrosis occurs in tendon disease. transforming growth factor beta (tgfβ) and its associated superfamily are known to be key drivers of fibrosis and to modulate extracellular matrix homeostasis. we hypothesised that differential expression of tgfβ superfamily members would exist between samples of human rotator cuff tendons with established disease compared to healthy control tendons. methods: healthy and diseased rotator cuff (supraspinatus) tendons were collected from patients presenting to an orthopaedic referral centre. diseased tendinopathic (intact n=23) and healthy rotator cuff tendons (n=10) were collected via ultrasound-guided biopsy, torn tendons were collected during routine surgical debridement (n=30). healthy hamstring tendons were collected from patients undergoing acl reconstruction (n=*). immunohistochemistry and quantitative real-time polymerase chain reaction were used to investigate the expression profiles of tgfβ superfamily members in these healthy and diseased tendon tissues. results: tgfβ superfamily members were dysregulated in diseased compared to healthy tendons. specifically, tgfβ-1, tgfβ receptor r1 and tgfβ r2 proteins were reduced (p<0.01) in diseased compared to healthy tendons. at the mrna level, tgfβ r1 was significantly reduced in samples of diseased tendons, whereas tgfβ r2 was increased (p<0.01). discussion: we propose that down regulation of tgfβ pathways in established tendon disease may be a protective response to limit disease-associated fibrosis. disruption of the tgfβ axis with disease suggests associated downstream pathways may be important for maintaining tendon homeostasis and health. the findings from our study suggest that patients with established tendon disease would be unlikely to benefit from therapeutic tgfβ blockade, which has been investigated as a treatment strategy in several animal models. future studies should investigate the expression profile of fibrotic mediators in earlier stages of tendon disease to improve understanding of the targetable mechanisms underpinning tendon fibrosis. p19: incidence of lower limb tendinopathy in brazilian youth athletes natália fn bittencourt 1,2 , luciana de michelis mendonça 3 , daniel freitas maciel 4 , gabriela gp gonçalves 4 , rodrigo vaz 4 1 sports physical therapy department – minas tênis clube, brazil ; 2 centro universitário uni-bhbrazil ; 3 physical therapy department universidade federal dos vales do jequitinhonha e mucuri, brazil; 4 sports science and medicine departmentminas tênis clube, brazil presenting author e-mail address: nataliabittencourt@yahoo.com.br. introduction: the incidence of lower limb tendinopathy (llt) has been documented in elite athletes 1 , but in youth athletes the incidence is unclear. van mechelen proposed that the first step to properly prevent sports injury is to determinate the injury profile in a specific population 2 . preventing llt is important, because rehabilitation is complex and this injury may result in long-standing impairment of athletic performance. the purpose of this study was to investigate the incidence of llt in brazilian youth athletes. methods: a one-year prospective study was performed in 442 brazilian youth athletes from volleyball, basketball, judo, gymnastic, tennis and indoor soccer (113 female and 329 male). the sample had a mean age of 14.1 ± 2.9 years, mean height of 1.75 ± 1,2 meters and mean body mass mailto:stephanie.dakin@ndorms.ox.ac.uk mailto:nataliabittencourt@yahoo.com.br 18 s af. j sports med vol. 28 no.2 supplement 2016 of 59.4 ± 17.4 kilograms. the examination included questioning around individual characteristics (weight, age, height, and training background) and a physician performed the diagnosis of tendinopathy clinically. to be classified as having llt, participants met the eligibility criteria of: lower limb tendon pain on at least one of jumping/landing, running or changing directions and pain on palpation of the llt tendon 3,4 . results: from 221 injuries, tendinopathy was the main complaint (24%), followed by ligament injury (22%). the llt overall incidence rate was 10.7/1000 exposure hours (ci 95%: 7.0-14.4). the frequency of current symptoms was higher in male volleyball athletes (28%), followed by judo, basketball and female volleyball players (16% each one) and the lowest frequency was in gymnastic, tennis and indoor soccer (5% each one). patellar tendon was the most injured (47%), followed by achilles tendon (16%) and adductor tendon (2%). male athletes (72%) had higher frequency of tendinopathy than female athletes (28%). conclusion: the results showed higher incidence of tendinopathy in youth athletes (14,5%) compared to the literature. for example, cassel et al reported prevalence of 7,8% of llt in german youth athletes 3 . as in elite athletes, volleyball had the higher prevalence of tendinopathy. interesting, judo athletes had the same frequency than basketball. therefore, youth athletes are at high risk of llt and it is necessary to assess these athletes in the pre-season in order to identify factors that could be associated to llt and plan an effective prevention program. references: 1. lian ob, engebretsen l, bahr r. prevalence of jumper's knee among elite athletes from different sports: a cross-sectional study.am j sports med. 2005 apr;33(4):561-7. epub 2005 feb 8. 2. van mechelen w., hlobil h., kemper h.c.g. incidence, severity, aetilogy and prevention of sports injuries. sports medicine, v14, n.2, p: 82-99, 1992. 3. cassel m, baur h, hirschmüller a, carlsohn a, fröhlich k, mayer f. prevalence of achilles and patellar tendinopathy and their association to intratendinous changes in adolescent athletes. scand j med sci sports 2015: 25: e310–e318. 4. cook jl, khan km, kiss zs, et al. 2001. reproducibility and clinical utility of tendon palpation to detect patellar tendinopathy in young basketball players. br j sports med 35:65 – 69. p20: effect of iso-inertial squat on incidence of patellar tendinopathy in elite male soccer players bruno mazziotti 1,4,5 , natalia fn bittencourt 2,3 , luciano rosa 1,4 , caio mello 1 , joaquim grava 1 , cesar amorim 5 , 1 biomechanics laboratory. s. c. corinthians paulista, são paulo – brazil; 2 sports physical therapy department – minas tênis clube, brazil; 3 centro universitário uni-bh brazil; 4 mechanical engineering department – feg/unesp,são paulo – brazil; 5 universidade cidade de são paulo, são paulo, brazil presenting author e-mail address: brunomazziotti@hotmail.com introduction: patellar tendinopathy (pt) is common in elite soccer and the recurrence rate is high 1 . this condition could be related to acl reconstruction or overuse due to high amount of exposure. typical soccer performance involves acceleration and deceleration at high intensity of a constant mass. iso-inertial squat exercises (yoyo system) have those same characteristics during concentric and eccentric work 2 . this is more similar to athletic performance than isokinetic and isometric exercises 2 . moreover, it could promote specific load to muscle and tendon tissue and increase tensile strength. the purpose of this study was to investigate the effect of iso-inertial exercises on incidence of patellar tendinopathy in elite male soccer players. methods: thirty elite male soccer players from brazilian first division were recruited and followed during one season (10 months). the sample had mean age of 26.24±5.17 years, mean height of 1.79 ± 0.06 meters and mean body mass of 78.58 ± 7.58 kilograms. all athletes performed typical strength http://www.ncbi.nlm.nih.gov/pubmed/?term=lian%252520ob%25255bauthor%25255d&cauthor=true&cauthor_uid=15722279 http://www.ncbi.nlm.nih.gov/pubmed/?term=engebretsen%252520l%25255bauthor%25255d&cauthor=true&cauthor_uid=15722279 http://www.ncbi.nlm.nih.gov/pubmed/?term=bahr%252520r%25255bauthor%25255d&cauthor=true&cauthor_uid=15722279 http://www.ncbi.nlm.nih.gov/pubmed/15722279 mailto:brunomazziotti@hotmail.com 19 s af. j sports med vol. 28 no.2 supplement 2016 conditional training and they were exposure to the same 380 hours of soccer matches and training session. group a (n=15) didn’t perform iso-inertial exercises and group b (n=15) did iso-inertial squat two times a week (6 x 10 repetition). results: group a had 7 cases of pt and group b (iso-inertial exercises) had 3 cases of pt. this study presented a decrease of 57% in pt frequency on iso-inertial squat group. conclusion: the results showed a lower incidence of patellar tendinopathy in elite male soccer athletes, which performed yoyo iso-inertial squat exercises during a season. these preliminary data might indicate that tendon tissue benefits from exercises that involve acceleration and deceleration of a constant mass. references: 1. hägglund m1, zwerver j, ekstrand j. epidemiology of patellar tendinopathy in elite male soccer players. am j sports med. 2011 sep;39(9):1906-11. doi: 10.1177/0363546511408877. 2. murphy, a.j., wilson g.j. and pryor j.f. (1994) use of the iso-inertial force mass relationship in the prediction of dynamic human performance. eur j ap physiol. 69: 250-257. p21: temperature differences in affected compared with unaffected legs in subjects with unilateral achilles tendinopathy: a pilot study s o’neill, 1 ; c swan 1 ; l mclelland 2 ; t coats 2 ;m sims 3 . 1 department of medicine, university of leicester, united kingdom; 2 emergency medicine academic department, leicester royal infirmary, united kingdom; 3 department of physics and astronomy, university of leicester, united kingdom. presenting author e-mail address: so59@leicester.ac.uk introduction: achilles tendinopathy is associated with neovascularization, and metabolic changes. autonomic nervous system alterations, such as changes in the colour and temperature of the overlying skin, are often observed. multiple authors have suggested that thermography may be useful clinically and in research. there are several small studies on equine and human tendinopathic tendons suggesting alterations to overlying skin temperature but no quantitative measurements. aim determine if there are between limb differences in subjects with achilles tendinopathy methods: observational study involving 16 subjects with chronic achilles tendinopathy. a standardized protocol was developed using a template to position the participant. this template positioned the subject 120cm from the thermal camera (forward looking infrared (flir) sc620 camera with thermal sensitivity of <0.04˚c at 30˚) with the camera mounted level with the achilles tendon (10cm from the floor). stable environmental conditions were used for all subjects with equal time for each participant to acclimatize to the environment. initially two regions of interest (roi) were determined. these were the site of most tenderness and the posterior of the calcaneus. analysis involved limb comparison between affected and un-affected limbs. results: at the site of most tenderness the affected leg measured 28.0°c (ci 26.8-29.2) and the control (unaffected) leg measured 28.1°c (ci 26.9-29.3), a difference of 0.075°c (p=0.705, nonsignificant). the 2 nd roi (calcaneus) measured 0.5°c cooler on the affected side at 26.2°c (ci 25.127.4) compared with the un-affected side of 26.7°c (ci 25.527.9) (p=0.018). discussion: in this preliminary study in individuals with unilateral achilles tendinopathy there was no difference in temperature at the site of most tenderness between the affected and un-affected limbs. this could be related to central or bilateral changes or there may indeed be no effect of tendinopathy on skin temperature. at the 2 nd roi (posterior of the calcaneus) the affected limb was cooler – a difference that was small, but higher than the accepted difference between limbs of 0.38°c. this http://www.ncbi.nlm.nih.gov/pubmed/?term=h%c3%a4gglund%20m%5bauthor%5d&cauthor=true&cauthor_uid=21642599 http://www.ncbi.nlm.nih.gov/pubmed/?term=zwerver%20j%5bauthor%5d&cauthor=true&cauthor_uid=21642599 http://www.ncbi.nlm.nih.gov/pubmed/?term=ekstrand%20j%5bauthor%5d&cauthor=true&cauthor_uid=21642599 20 s af. j sports med vol. 28 no.2 supplement 2016 preliminary study did not find the previously suggested pattern of temperature difference; further work is warranted to understand the complex changes and to further elucidate the potential place of thermal imaging in achilles tendinopathy. p22: is widespread mechanical sensitivity a feature of achilles tendinopathy? s o’neill, 1 ; r masterton 1 department of medicine, university of leicester, united kingdom. presenting author e-mail address: so59@leicester.ac.uk introduction: tendinopathy research has recently begun to assess the changes that occur in the central nervous system. the majority of these studies have focussed on the upper limb with only two assessing lower limb tendinopathy. much of this research has focussed on whether the central nervous system becomes mechanically hypersensitive in the same way as observed in upper limb tendinopathy or other chronic msk conditions. only one small pilot (n=8 in each group) study has assessed mechanical sensitivity in relation to achilles tendinopathy. due to the gap in the literature this study aimed to determine if individuals with chronic achilles tendinopathy present with widespread mechanical hyperalgesia. methods: observational case control study. 17 subjects with chronic achilles tendinopathy, mean age 49, and 15 healthy controls, mean age 40, were recruited. mechanical sensitivity was assessed using an electronic von freys device. 5 points were used – achilles tendon, lateral femoral condyle, abdominal wall, anterior forearm and ulnar styloid process. testing was completed by the same experienced user. results: skin sensitivity for each area is reported as mean and (sd) in grams, with the at group versus the control. achilles tendon 304.4(171.8): 340.2 (134.6), lateral femoral condyle 409.2 (164.7):450.7 (191), abdominal wall 362.8 (144.3):346.4 (158.2), anterior forearm 338.6 (144.8): 345 (163.7) and ulnar styloid 424.9 (168):381.7 (200.6). for each of the 5 areas measured there was no statistical or clinically important between group differences: achilles tendon (p=0.521), lateral femoral condyle (p=0.514) abdominal wall (p=0.761), anterior forearm (p=0.906) and ulnar styloid process (p=0.512). visa a score did not correlate to mechanical sensitivity of the achilles tendon (p=0.146). discussion: widespread mechanical hyperalgesia does not appear to be a feature of achilles tendinopathy. this finding supports previous research findings [1] and suggests that achilles tendinopathy does not invoke widespread mechanical hyperalgesia. this finding does not mean that central sensitisation does not occur in achilles tendinopathy [2] but rather that it does not influence mechanical hyperalgesia. this seems to correspond to the common clinical presentation and diagnostic criteria of localised tendon pain. references 1. skinner, i,w. debenham, j, r. krumenacher, s, a. bulsara, m, k. wand, b, m. (2014) ‘chronic mid portion achilles tendinopathy is not associated with central sensitisation’. pain and rehabilitation the journal of the physiotherapy pain association. (37) 34-40 2. tompra, n. dieen, j. coppieters, m. (2016) central pain processing is altered in people with achilles tendinopathy. british journal of sports medicine. 0, p1-6. doi:10.1136/bjsports-2015-095476 p23: acute sensory and motor response to 45-seconds heavy isometric holds for the plantar flexors in patients with achilles tendinopathy 21 s af. j sports med vol. 28 no.2 supplement 2016 s o’neill, 1 ; j radia 1 ; k bird 1 ;ms rathleff 2 ; t bandholm 3 ; m jorgensen 4 and k thorborg ,5 1 department of medicine, university of leicester, united kingdom; 2 research unit for general practice in aalborg and department of clinical medicine, aalborg university, denmark; 3 physical medicine & rehabilitation research – copenhagen (pmr-c), amagerhvidovre hospital, university of copenhagen, copenhagen, denmark; 4 department of geriatrics, aalborg university hospital, denmark; 5 sport orthopedic research center – copenhagen (sorc-c), amager-hvidovre university hospital, copenhagen, denmark presenting author e-mail address: so59@leicester.ac.uk introduction: recent studies have suggested that heavy isometric exercises for the quadriceps improve pain and muscle function in subjects with patella tendinopathy [1]. it is unclear whether this approach is effective for other lower limb tendon pain. aim – to investigate the immediate effects of heavy isometric exercises of the plantarflexors on pain output and muscle force output in individuals with achilles tendinopathy. methods: 16 individuals (5 female) with achilles tendinopathy for more than three months participated. pain response (0-10) to most provocative achilles activity (heel raises or hopping) was recorded and rated using the numerical rating scale (nrs). participants then underwent mechanical pressure pain threshold testing using an electronic von freys device and strength testing using an isokinetic dynamometer to measure plantarflexor strength. subjects had their maximal voluntary isometric strength measured and completed five 45-second isometric contractions – separated by 2 minute rest, at 70% mvc using a fysiometer [2]. pain sensitivity and strength were assessed immediately after completion of the exercise protocol. results: only 9 of the 16 participants reported pain during either heel raises or hopping. mean (sd) nrs for the symptomatic test was 4.2(1.9) pre intervention and 4.8 (3.2) post intervention, p=0.219. mechanical pressure pain thresholds did not change from pre 335.8n (193.7) to post 313.1n (176.4) intervention (p=0.396). concentric plantarflexor torque at 90º/sec increased 6 nm (13%) from pre 47(14.5)nm to post 53(18.5)nm intervention (p=0.039). no other changes in plantarflexor strength were observed across contraction modes and speeds: concentric 225º/sec, 34(11.6)nm versus 33(6.6)nm (p=0.917); eccentric 90º/sec, 99(34.2)nm versus 107(41.4)nm (p=0.350). discussion: in patients with achilles tendinopathy, heavy isometric exercises – did not acutely change sensory and motor output to a clinically relevant degree. although a small increase in concentric plantarflexor torque at 90º/sec was observed, this is less than the smallest detectable change for this measure. furthermore, the clinical value of nrs testing during functional testing in patients with achilles tendinopathy seem a doubtful approach as floor effect presented in many patients. this preliminary study suggests that patients with achilles tendinopathy may not respond to heavy isometric holds in the same way as patients with patellar tendinopathy. references 1. rio e, kidgell d, purdam c, gaida j, moseley l, pearce a, et al. isometric exercise induces analgesia and reduces inhibtion in patellar tendinopathy. british journal of sports medicine 2015;49(19):1277-1283. 2. blomkvist aw, andersen s, debruin ed, jorgensen mg isometric hand grip strength measured by nintendo wii balance board a reliable new method. bmc musculoskeletal disorders 2016:3(17): doi: 10.1186/s12891-016-0907-0. p24: an investigation into the effect different window size analysis has on achilles tendon ultrasonographic tissue characterisation echo-type quantification. s barry 1 ; s o’neill 2 22 s af. j sports med vol. 28 no.2 supplement 2016 1 faculty of health and life sciences, coventry university, uk, 2 department of medicine and biological sciences, university of leicester, uk presenting author e-mail address: sjb111@le.ac.uk introduction: grey scale ultrasonography (us) is a commonly used modality to visualise tendon structure having the capacity to allow accurate measurement of tendon thickening and identification of hypoechogenicity to aid the diagnosis of tendon pathology. however, routine ultrasonography relies on subjective quantification of tendon pathology and is not responsive to subtle changes in tendon structure. ultrasonographic tissue characterisation (utc) provides a detailed visulisation of tendon matrix structure and quantification of 4 echo-types indicating the degree of tendon bundle alignment. the utc standardizes many us parameters but offers 3 distinct options for scan analysis referred to as window sizes (ws). this study investigates the effect that ws has on echo-type quantification. methods: twenty participants with no history of achilles tendinopathy were recruited. a 4cm section of the mid-portion of both achilles tendons was scanned in a standardized prone position producing 200 contiguous transverse images which were automatically interpolated to form a tendon volume. tendon structure was quantified using dedicated utc algorithms for ws 25, 17 and 9. results: a reduction in percentage of echo-type i was seen as the ws reduced, (ws: mean (sd)), 25:73.61% (5.96); 17: 69.91% (5.46); 9: 64.65% (4.59). all other echo-types increased, echo-type ii 25:25.54% (5.89); 17:28.71% (5.29); 9:32.62% (4.35), echo-type iii 25:0.59% (0.48); 17: 0.96% (0.67): 9:1.39% (1.14), echo-type iv 25:0.27% (0.35); 17: 0.4% (0.42); 9:0.71% (0.58). however, the echo-type values for each corresponding ws remained highly correlated echo-type i 25:17:9 r = 0.998:0.998:0.993; echo-type ii 25:17:9 r = 0.997:0.984:0.969: echo-type iii 25:17:9 r = 0.990:0.981:0.948; echo-type iv 25:17:9 r = 0.99:0.983:0.966. discussion: utc analysis is becoming more prevalent in tendinopathy research however studies do not always state which ws was used for scan analysis. to date most studies have used ws 25 despite indications that smaller ws improve scan resolution and therefore ability to detect small scale changes. study results indicate that utc analysis in different ws significantly alters the quantification of echo-types i-iv demonstrating proportionally fewer aligned tendon bundles in smaller ws. however the echo-type values for each corresponding ws were highly correlated indicating high internal validity for utc analysis of tendon structure. p25: an exploration of intron 4 polymorphisms within the col5a1 gene and its association to anterior cruciate ligament injury risk f firfirey 1 , m-j laguette 1 , av september 1 ,m collins 1 1 division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, cape town, south africa. presenting author e-mail address: firzanafirfirey@gmail.com background: anterior cruciate ligament (acl) injury is a multifactorial condition and one of the most common musculoskeletal soft tissue injuries in competitive sports. to date, several genetic association studies have identified polymorphisms which alter an individual’s risk of injury. the col5a1 gene is an important regulator of collagen fibrillogenesis in ligaments and tendons. previous studies have identified sequence variants within the 3’-utr of col5a1 resulting in altered col5a1 mrna stability. regions within intron 4 have been implicated in splicing. the objective of this study was therefore to examine the relationship between polymorphisms in intron 4 of col5a1 and acl injury risk. methodology: a case control genetic association study was conducted. south african participants recruited for this study included 253 cases (152 non-contact and 101 contact acl injuries) and matched 233 asymptomatic controls from which venous blood were obtained for dna extraction. two single nucleotide polymorphisms (snps), rs4841926(c/t) and rs3922912 (a/g), were identified using haploreg v3 and the seattlesnps databases. haploreg v3 were set to identify snps of 0.8 linkage disequilibrium within a 1000 base pairs. the genome variation server in the seattle database was mailto:firzanafirfirey@gmail.com 23 s af. j sports med vol. 28 no.2 supplement 2016 used to identify tagged snps and confirm the results obtained in haploreg. the samples were genotyped using taqman® assays through real-time polymerase chain reaction (rt-pcr). fisher’s exact test and pearson’s chi squared analysis were used to analyse differences in genotype and allele frequencies. genotype and allele frequencies were also stratified according to mechanism of injury and gender. statistical significance was accepted at p < 0.05. results: no statistical differences in genotype or allele frequencies were observed for col5a1 rs4841926 (p=0.6893) and rs3922912 (p=0.3895) between the case and control diagnostic groups. furthermore, no statistical differences were noted when diagnostic groups were stratified by gender or mechanism of injury. conclusion: no genetic associations were identified in this study. however, future studies should examine a wider region in a larger sample size to allow for risk specific haplotypes to be identified. p26: investigating an in silico approach to identify genetic susceptibility loci for musculoskeletal soft tissue injuries s dlamini 1 , c saunders 2 , m collins 1 , j gamieldien 2 , a september 1 1 division of exercise science and sports medicine, department of human biology, university of cape town, south africa, 2 south african national bioinformatics institute university of western cape presenting author e-mail address: dlaminisenanile@gmail.com in competitive and recreational athletes, musculoskeletal injuries of soft tissues such as ligaments and tendons are common. to date, most of the genes and genetic loci implicated were identified through a case-control, candidate gene association approach. based on all the information that has been obtained through candidate gene association studies, the aim of this study was to use an in silico approach where bioinformatics was included to find new information through assessing the feasibility and performance of bioontological relationship graph database (borg), an in silico tool which integrates multiple sources of genomic and biomedical knowledge into an on-disk semantic network where human genes and their orthologs in mouse and rat are central concepts mapped to ontology terms. borg was used to identify a comprehensive list of potentially biologically significant genetic loci to be tested for association with risk of achilles tendinopathy and anterior cruciate ligament injury. the list was then compared and refined using next generation sequencing data. from screening all human genes, 3500 genes and a further 10 microrna’s were found to be linked to tendinopathy. further preliminary characterisation has shown that these genes are differentially expressed in tendinopathy, functionally linked to features of tendinopathy either through signalling or pathways etc. p27: the casp8 gene and risk of carpal tunnel syndrome k seale¹, mc burger¹, h de wet², a september¹, m posthumus¹, m collins¹ ¹division of exercise science and sports medicine, department of human biology, university of cape town, south africa; ²life occupational health, life healthcare, cape town, south africa presenting author e-mail address: kirsten.seale@alumni.uct.ac.za introduction: idiopathic carpal tunnel syndrome (cts) is a commonly occurring mono-neuropathy in the upper limb, of which the direct cause remains unknown. although primarily considered a neuropathy, the possible involvement of the flexor tendons in the pathogenesis of cts has been proposed, and in support of this, tendinopathy and tenosynovitis have both been mentioned as possible precursors for cts. in addition, the role of genetics in the pathogenesis of this condition is plausible, and recent research has identified dna sequence variants within genes encoding structural 24 s af. j sports med vol. 28 no.2 supplement 2016 components of tendons and tendon regulatory proteins to modulate risk of cts. the aim of this study was to determine whether sequence variants within the caspase-8 (casp8) gene, a primary operator in the apoptosis pathway, are also associated with cts. sequence variants within the casp8 gene have been previously associated with risk of achilles tendinopathy (at), a multifactorial overuse pathology 1 . methods: one hundred and three self-reported coloured south african participants, with a history of carpal tunnel release surgery (cts) and one hundred and forty-seven matched control (con) participants without any reported history of cts symptoms were genotyped using the taqman® allelic discrimination method (applied biosystems, foster city, california, usa) for the casp8 rs3834129 (i/d), rs1045485 (g/c) and rs13113 (t/a) sequence variants. all statistical analyses were performed on the programming environment r and r packages. results: no independent associations were found for all three of the casp8 variants between the cts and con groups. two inferred haplotype combinations (rs3834129-rs1045485-rs13113 and rs3834129-rs13113) were, however, found to have a significant relationship with cts in all participants and in females separately. discussion: variants within the casp8 gene have been found to be collectively significantly associated with cts, implicating the apoptosis pathway as biologically significant in the underlying pathogenesis of cts. the main focus of this research is aimed at underpinning the genetic susceptibility to cts, and how associated variants may contribute to the inter-individual variation in tendon structure and function. the identification of genetic risk factors pertaining to cts may potentially provide insight into the management of injury in susceptible individuals. references: 1. nell, e.m., van der merwe, l., cook, j., handley, c.j., collins, m., and september, a. v. (2012). the apoptosis pathway and the genetic predisposition to achilles tendinopathy. j. orthop. res. 30, 1719–1724. p28: genetic variants in the proteoglycan, decorin and risk of carpal tunnel syndrome. jl judd 1 ; m burger 1 ; h de wet 2 ; m collins 1 1 division of exercise science and sports medicine, department of human biology, university of cape town, po box 115, newlands 7725, south africa; 2 life occupational health, western cape, south africa presenting author e-mail address: jddjen001@myuct.ac.za introduction: carpal tunnel syndrome (cts) is generally considered to be a multifactorial condition and causal factors are still under debate 1 . although primarily considered to be a neuropathy, recent evidence suggests that tendinopathy may be involved in the aetiology of cts. anatomically, the carpal tunnel structure contains nine flexor tendons indicating that entrapment of the median nerve within this structure, leading to an increase in pressure, could in part, be attributed to these tendons. variants within genes encoding the essential structural components of tendons have previously been associated with risk of cts 2-4 . the dcn rs516115 (a/g), within the gene encoding decorin, an important proteoglycan, has previously been associated with altered risk of musculoskeletal soft tissue injuries (collins et al., 2015) and therefore the aim of this study was to determine whether dcn rs516115 (a/g) was independently associated with altered risk of carpal tunnel syndrome. methods: a total of 71 self-reported coloured participants with a history of cts release surgery and 100 appropriately matched controls have thus far been genotyped for the dcn rs516115 (a/g) variant. a pearson’s chi-squared test was used to determine any significant differences between genotype distributions or any other categorical data of the groups. results and discussion: preliminary results indicate that there is no significant difference between cases and controls, for the dcn rs516115 variant (p=0.933). it is however important to note that the 25 s af. j sports med vol. 28 no.2 supplement 2016 sample size of this study is small and the findings need to be repeated in other, larger studies. additionally, this finding does not exclude other variants within dcn to potentially alter risk of cts. references: 1. mcdiarmid, m., oliver, m., ruser, j., & gucer, p. (2000). male and female rate differences in carpal tunnel syndrome injuries: personal attributes or job tasks? environmental research, 83(1), 23–32. 2. burger, m. c., de wet, h., & collins, m. (2014). the bgn and acan genes and carpal tunnel syndrome. gene, 551(2), 160–166. 3. burger, m., de wet, h., & collins, m. (2014). the col5a1 gene is associated with increased risk of carpal tunnel syndrome. clinical rheumatology, 34(4), 767–774. 4. collins, m., september, a. v, & posthumus, m. (2015). biological variation in musculoskeletal injuries : current knowledge, future research and practical implications. british journal of sports medicine, 49, 1–8. p29: evaluating polymorphisms within the proteoglycan encoding genes with achilles tendinopathy susceptibility k willard 1 ; laguette m-j 1 ; cj saunders 2 ; j. gamieldien 2 ; m collins 1 ; and september av 1 1 division of exercise science and sport medicine, department of human biology, university of cape town, 2 south african national bioinformatics institute/mrc unit for bioinformatics capacity development, university of the western cape presenting author e-mail address: k14581035@gmail.com introduction: compromised functional capacity of tendons and ligaments has been associated with musculoskeletal soft tissue (msk) injuries such as achilles tendinopathy (at) and anterior cruciate ligament (acl) ruptures. variants within genes that encode proteoglycans such as acan (rs235191, rs1042630 and rs1516797), bgn (rs1126499, rs1042103) and dcn (rs516115) have previously been associated with susceptibility to acl ruptures 1 . the functional significance of these loci are unknown. the aim of this study was to refine the disease susceptibility loci for msk injuries by genotyping acan, bgn and dcn gene variants identified through whole exome sequencing (wes) of exemplar cases (clinically diagnosed with at) and controls (unaffected). methods: the wes approach identified 56 variants within the acan, bgn and dcn genes. the following loci were prioritised and subsequently genotyped: acan (rs34949187, rs2351491, rs1042630, rs1042631, rs1516797, rs1126823), bgn (rs1126499, rs1042103, rs111325687) and dcn (rs7441, rs516115) in a south african and british cohort. the south african cohort comprised of 112 patients with at and 120 asymptomatic, matched controls. the genotype and allele frequency distributions were evaluated using the r programming language and environment. statistical significance was accepted at p<0.05. results: preliminary investigations indicate a significant difference in the genotype and allele frequency distribution between cases and controls for the acan rs1516797 variant. the tt genotype was over-represented in the controls compared to the at group (con: 58.2%; at: 38.1%; p=0.038; or=0.649; 95%ci 0.21 to 2.04). no other differences between cases and controls in genotype or allele frequencies were identified for the variants genotyped. discussion: further evaluation and interrogation of variants identified through the wes approach is still underway in an attempt to understand the genetic factors underpinning at susceptibility which potentially maps to these proteoglycan encoding genes. references: 1. mannion s, mtintsilana a, posthumus m, et al. 2014. genes encoding proteoglycans are associated with the risk of anterior cruciate ligament ruptures.br. j. sports med. 48(22):1640–6 26 s af. j sports med vol. 28 no.2 supplement 2016 p30: pieces to the puzzle: identifying variants associated with musculoskeletal soft tissue injuries using whole exome sequencing a gibbon a 1 , cj saunders 2 , j gamieldien 2 , m collins m 1 , av september 1 1 division of exercise science and sports medicine, department of human biology, university of cape town, cape town, south africa; 2 south african national bioinformatics institute/mrc unit for bioinformatics capacity development, university of the western cape, belville, cape town, south africa presenting author email address: colljsaunders@gmail.com introduction: dna sequence variants have been associated with the risk of musculoskeletal soft tissue injuries, implicating the role of genetics in the aetiology of common sporting injuries including achilles tendinopathy and anterior cruciate ligament ruptures. risk conferring variants have primarily been identified using a hypothesis driven candidate gene approach. this approach, using a priori hypothesis of a gene’s products involvement in injury, has implicated several biological pathways in disease development. however, it is not plausible to independently characterise all risk conferring variants in injury development using this method. therefore, this study aimed to further define the genetic signature of musculoskeletal soft tissue injuries mapping to established biological pathways by utilizing next generation sequencing technologies and a host of bioinformatics tools. material and methods: whole exome sequencing (wes) was conducted on 10 cases and 10 controls representing divergent extremes of the injury spectrum. cases were <35 years of age, suffered bilateral tendinopathy of the midportion and/or reported several chronic achilles tendon injuries. controls were >47 years of age, physically active and reported no previous injuries. paired end wes, with the inclusion of the untranslated regions and mirna genes, was performed using the agilent v5+utr (71mbp) capture kit on the illumina hiseq 2000/2500 platform at 30x coverage. results: preliminary results indicate the presence of 3016 variants mapping across the exome with allele frequency differences of ≥30% between cases and controls. signals of particular interest include the matrix metalloprotease (mmp) gene cluster on chromosome 11q22 in addition to the regions spanning the tenascin-c (tnc) and the alpha 1 chain of type i (col1a1) and type xxvii (col27a1) collagen genes respectively. conclusion: through this multidisciplinary approach, these signals of interest are being explored using a case-control genetic association design in larger cohorts and may provide valuable knowledge into the aetiology of musculoskeletal soft tissue injuries. p31: tgf-β stimulated bgn gene expression in a genetic susceptibility model for musculoskeletal soft tissue injuries: a pilot ex vivo study. m-j laguette 1 , l alves de souza rios 1 , k willard 1 , m collins 1 and av september 1 . 1 division of exercise science and sport medicine, university of cape town, cape town, south africa. presenting author e-mail address: nancylaguette@gmail.com introduction: variants in several genes, including proteoglycan encoding genes such as biglycan (bgn), have been implicated in modulating the risk of musculoskeletal soft tissue injuries. biglycan is involved in fibrillogenesis, tendon development and healing. tgf-β is a mediator of the matrix remodelling pathway and, as observed in the context of injury and healing, is able to regulate bgn expression. variants within bgn associate with anterior cruciate ligament ruptures (rs1126499, c/t and rs1042103, a/g) and with carpal tunnel syndrome (rs1126499). the primary aim of this study was to examine the relative bgn mrna expression, in skin fibroblasts of healthy individuals with a known bgn genotype. specifically, the effect of bgn rs1042103 (a/g) and rs1126499 (c/t) on its mrna expression was examined (a) at baseline (n=10) and (b) in response to tgf-β1 treatment (n=4). 27 s af. j sports med vol. 28 no.2 supplement 2016 methods: participants were grouped according to their genotypes forming an increased (tt/aa and tt/ag at rs1126499/rs1042103 respectively, n=7) and a decreased risk group (cc/gg and cc/aa at rs1126499/rs1042103 respectively, n=3). skin biopsies were obtained from consenting healthy participants with a known genotype at the loci of interest. primary skin fibroblast cell lines were obtained. cells were treated with 10ng/ml of purified tgf-β1. total mrna was extracted, cdna was generated and q-rt-pcr was performed. relative expression of the target genes were compared between risk groups. results: bgn mrna expression was not statistically different between the increased (cc/gg and cc/aa) and decreased risk (cc/gg and cc/aa) groups (p=0.84) at baseline. tgf-β1 treatment resulted in elevated expression of bgn in both groups with a higher expression observed in the decreased risk (cc/gg and cc/aa) group (2.40 ± 0.67; n=11) compared to the increased risk (tt/aa and tt/ag) group (1.47 ± 0.74; n=6) (p=0.024). discussion: expression of bgn mrna at baseline did not differ between genotype groups. however, when treated with tgf-β1, bgn mrna levels were higher in the decreased risk group. the latter may be more readily able to enter processes such as healing and fibrillogenesis given the greater response to tgf-β1 w.r.t. bgn expression. this study highlights the possible effect of genetic variations on gene expression. p32: more tendinopathy than inflammatory arthritis in a new patient rheumatology clinic. a retrospective review of 397 new patients p kirwan 1,2 , hp french 2 , t duffy 3 1 physiotherapy department, connolly hospital, blanchardstown, dublin 15, 2 school of physiotherapy, royal college of surgeons in ireland, dublin 2 3 rheumatology department, connolly hospital, blanchardstown, dublin 15 presenting author e-mail address: paulkirwan@rcsi.ie introduction: tendinopathy is a common musculoskeletal complaint. a recent dutch 1 study has indicated that lower limb tendinopathy has a higher incidence (10.52 per person-years) than osteoarthritis (8.4 per 1000 person-years). the purpose of this review was to establish the number of patients with tendinopathy/tendon pain presenting to a general ‘new patient’ rheumatology clinic. methods: data were collected consecutively on all patients assessed by one experienced physiotherapist working in the ‘new patient’ rheumatology clinic from dec 2010 to may 2016. no triage of these patients was performed, therefore doctors and physiotherapist see similar patients. a retrospective review of the data collected and medical charts was undertaken. the number of patients diagnosed with tendinopathy by the physiotherapist was noted, and descriptive statistical analysis was undertaken. the diagnosis of tendinopathy was made clinically. results: in total, 392 patients were assessed over the time period, 265 females and 127 males, representing a 2:1 ratio for females to males. the mean age was 49 ± 13.7 years. tendinopathy was diagnosed in 134 patients, therefore 34% of all the patients assessed had tendon pain. thirty-two patients, 8% of the total, had bilateral tendon pain. the total number of painful tendons was 166. the most common tendinopathy was rotator cuff tendinopathy accounting for 12% of patients (n=46), followed by gluteal tendinopathy representing 10% (n=38), whilst lateral elbow tendinopathy accounted for 9% of patients (n=31). medial elbow, tibialis posterior, proximal hamstring, peroneal, patellar and achilles tendinopathy accounted for the remaining 19 patients with tendinopathy. plantar fasciopathy was diagnosed in 7% of patients (n=27). an inflammatory arthritis was diagnosed in 20% of patients (n=78). discussion: results show that there is more tendinopathy than inflammatory arthritis in a ‘new patient’ rheumatology clinic. tendon pain combined with plantar fascia pain (41%), accounts for double the number of patients seen who were diagnosed with inflammatory arthritis. this review reveals the high proportion of those presenting to a ‘new patient’ rheumatology clinic have clinically diagnosed tendinopathy. it highlights the importance of knowledge of differential mailto:paulkirwan@rcsi.ie 28 s af. j sports med vol. 28 no.2 supplement 2016 diagnosis and evidencebased management of tendinopathy for doctors and other healthcare professionals working in rheumatology. references: 1. albers et al. bmc musculoskeletal disorders (2016) 17:16 29 s af. j sports med vol. 28 no.2 supplement 2016 p33: plantaris tendon, its presence, location and size in the region of the achilles tendon: an observational cadaveric study p kirwan 1,2 , hp french 2 1 physiotherapy department, connolly hospital, blanchardstown, dublin 15, 2 school of physiotherapy, royal college of surgeons in ireland, dublin 2 presenting author e-mail address: paulkirwan@rcsi.ie introduction: the plantaris tendon, which has long been disregarded as of little clinical importance, and absent in 7-20% of the population 1 , is attracting some interest of late. recently published studies indicate it is present in 98-100% of the population 2 and that it may act as a potential contributor to medial achilles tendon (at) pain. the aims of this study were threefold, to establish whether plantaris was present in a sample of cadaveric limbs, to identify its position in relation to the achilles tendon and to conduct measures of thickness and width of plantaris tendon. methods: the method previously described by van sterkenberg et al 2 was employed to identify the plantaris tendon. eighty-one cadaveric limbs, which had been previously dissected and were appropriate for inspection were assessed. plantaris was looked for in the region of the medial achilles. if plantaris could not be identified here, gastrocnemius was reflected back to reveal plantaris tendon beneath, and was then followed distally. all plantaris tendon measurements were taken 2-6 cm from the achilles insertion using a vernier caliper. results: the plantaris tendon was present in all 81 assessed limbs. plantaris was positioned medial to the achilles tendon in all limbs. this medial position was then further subcategorized into medial or ventromedial. plantaris tendon was positioned ventromedial to the achilles tendon in 59 (73%) of the limbs and medial to the achilles in 18 (22%) of the limbs. the mean width of the plantaris tendon was 2.8mm (range 1.2-5.0mm) and the mean thickness of the plantaris tendon was 0.8mm (range 0.11.6mm). discussion: plantaris was present in all limbs in keeping with recent studies. the measures of plantaris tendon width and thickness from this study found results similar to a recent cadaveric study 3 . plantaris has been estimated by experts to be implicated in 20% of at presentations, in particular those with medial achilles pain. this study found that 22% of plantaris tendons were located medial to the at, and this raises a question, whether a medially located plantaris has a greater potential to contribute to medial achilles tendon (at) pain compared to vm positioned plantaris tendons? references 1. van sterkenberg and van dijk. knee surg sports traumatol arthrosc 2011;19:1367-1375 2. van sterkenberg et al. j anat. 2011;218(3):336-41 3. olewnik et al. surg radiol anat. 2016 p34: plant derived rhcollagen scaffold combined with prp enhances healing in tendinopathy o shoseyov 1,2 , j seror 1 , r gueta 3 , f grynspan 4 , t amzel 1, a nyska 5 , n orr 1 . 1 collplant ltd., ness-ziona, israel. 2 the robert h. smith faculty of agricultural, food and environmental quality sciences, the hebrew university of jerusalem, rehovot, israel. 3 amorphical, ness-ziona, israel. 4 stem cell medicine ltd, jerusalem, israel. 5 sackler school of medicine, tel aviv university, israel, and consultant in toxicologic pathology presenting author e-mail address: nadav@collplant.com introduction: vergenix™str is a novel medical device scaffold composed of recombinant human type i collagen (rhcollagen) purified from bioengineered tobacco plants harboring the 5 human genes essential for the production of genuine human type i collagen(1). vergenix™str combined mailto:paulkirwan@rcsi.ie 30 s af. j sports med vol. 28 no.2 supplement 2016 with autologous platelets rich plasma (prp) was developed to address the limitations of prp treatment by providing a degradable matrix that retains the platelets at the vicinity of the injured tendon and extends the effect of growth factorsthus promotes healing. the device is intended for the treatment of tendinopathy. methods: preparation of product: vergenix™str is provided lyophilized and terminally sterilized by eto. the dry product is hydrated with autologous prp before injection into the injury site, preclinical evaluation: the product performance was assessed in a rat model for tendonitis and in a subcutaneous rat model of local growth factors release and degradation profile. clinical trial: a multicenter, prospective, open label, single arm trial was conducted to demonstrate the safety and performance of the product in 20 patients suffering from epicondylitis (tennis elbow). patients were followed for six months after a single injection while product performance was assessed by reduction in pain and recovery of motion using the standard patient related tennis elbow evaluation questionnaire (“prtee”). results: the subcutaneous rat model showed a significant extended release of pdgf and vegf in the product group as compared with prp alone. tendonitis model in rats showed clear advantage of the product as compared to prp alone. in the clinical trial, the new product provided clear clinical benefit to the patients with 80% and 90% of the patients showing at least 25% reduction in prtee score after 3 and 6 months respectively. these results are significantly better than results reported(2) for either prp alone or corticosteroids which had up to 68% (prp, 6 months) or 48% (corticosteroids, 3 months) of patients reporting at least 25% reduction in pain and motion score. conclusions: vergenix tm str combined with prp showed superior performance compared with prp alone in preclinical models and clinical setups. the results provide clear evidence supporting the use of vergenix tm str combined with prp for treatment of tendinopathy. references 1. stein h et al., biomacromolecules 2009 10(9) 2640 2. peerbooms et al, am j sports medicine 2010 38(2) 255 p35: non-rigid speckle tracking exploratory study for tendinopathy signaling in symptomatic subjects c carvalho 1 , s bogaerts 2 , l scheys 3 , j d’hooge 4 , k peers 2 , f maes 1, p suetens 1 1 ku leuven, esat/psi & uz leuven, mirc iminds, medical it dept, ku leuven, and uz leuven, 2 dept. of development and regeneration, 3 dept. of orthopedics, 4 dept. of cardiovascular sciences presenting author e-mail address: stijn_bogaerts@hotmail.com or stijn.1.bogaerts@uzleuven.be introduction: tendinopathies are one of the most common musculoskeletal injuries affecting both professional and recreational athletes. knowledge on tendon biomechanics is scarce and limited to some studies regarding global strain and local tissue deformation estimates in healthy subjects [1,2]. the objective of this study was therefore to investigate differences in the biomechanical behavior at the level of local tissue deformation between asymptomatic and symptomatic subjects. methods: high-frequency dynamic (2d+t) us data of both achilles tendons of 10 asymptomatic subjects and of the symptomatic achilles tendon of 8 subjects were acquired. symptomatic subjects were classified based on clinical interpretation of symptoms and morphological appearance on us in three groups: less severe (c1), medium severe (c2) and very severe (c3) tendinopathy. a non-rigid speckle tracking method was applied to each 2d+t us images, yielding the tissue deformation along the major deformation direction in each tendon voxel. four sub-regions were defined within the tendon, corresponding to proximal/distal and superficial/deep tendon regions. mean deformation for each subject was evaluated by averaging the deformation of the 4 sub-regions at the maximum isometric contraction point. comparison between symptomatic and asymptomatic group (c2+c3) was evaluated using a two-tailed homoscedastic t-test and a roc analysis was also http://www.ncbi.nlm.nih.gov/pubmed/?term=production+of+bioactive%2c+post-translationally+modified%2c+human+collagen 31 s af. j sports med vol. 28 no.2 supplement 2016 performed between the two groups. results: no significantly differences (p=0.06) were found between asymptomatic (n=20) and symptomatic (n=10) subjects. however, when comparing more severe symptomatic cases (c2+c3, n=7) with asymptomatic subjects, significant differences (p=0.02) were found. roc analysis between asymptomatic and more severe symptomatic cases (c2+c3) returned an area under the roc curve (auc) of 0.83. discussion: we show here, for the first time, preliminary results that allow the local biomechanical discrimination between more severe tendinopathy cases and asymptomatic cases. due to the small size of the datasets, more symptomatic images should be further acquired. further investigation should also be done for symptomatic subjects within c1 since these subjects present tissue deformation values close to the ones presented by asymptomatic subjects. this close range of deformation values may then be the reason for the non-significant difference found between asymptomatic and symptomatic cases. references: 1. arndt a, bengtsson a-s, peolsson m, thorstensson a, movin t. non-uniform displacement within the achilles tendon during passive ankle joint motion. knee surgery, sport traumatol arthrosc. 2012;20:1868–74. 2. slane lc, thelen dg. achilles tendon displacement patterns during passive stretch and eccentric loading are altered in middle-aged adults. med eng phys. 2015;37(7):712–6. p36: cross-sectional pilot study comparing function, morphology and biomechanical behavior of conservatively versus surgically treated achilles tendon ruptures. s bogaerts 1 , e smeets 2 , b trenson 1 , k peers 1 1 department of physical medicine & rehabilitation, university hospitals leuven, belgium 2 master student, faculty of medicine, ku leuven, belgium presenting author e-mail address: stijn_bogaerts@hotmail.com or stijn.1.bogaerts@uzleuven.be introduction: surgical treatment has been the treatment of choice in achilles tendon rupture (atr), but recent studies of conservative treatment have shown similar results with fewer complications. however, little is known about the difference in biomechanical behavior of the tendon after operative versus non-operative treatment. the goal of this study was to compare surgically versus conservatively treated achilles tendons ruptures, including an ultrasound-based assessment of regional mechanical tendon behavior. methods: patient related outcome measures were assessed using questionnaires (victorian institute of sports assessment – achilles, achilles tendon rupture score). functional evaluation was done using isokinetic plantar flexor strength on a biodex machine at 60°/sec and establishing the limb symmetry index (lsi), a heel rise endurance test, using the contralateral healthy leg as control. structural and mechanical properties were evaluated with 3d free hand ultrasound, measuring achilles tendon length from gastrocnemius muscle-tendon junction to calcaneal insertion at different ankle angles, and global strain, being the relative elongation from maximal dorsito plantar flexion. results: there were 3 surgically (2 male, 1 female) and 3 conservatively (2 male, 1 female) treated patients included. mean age overall was 52.8 years (sd = 9.79) with an average time from atr until testing of 10.8 months (sd = 1.47). preliminary results show a mean score of 84.00 (sd = 1) for atrs and 84.33 (sd = 16.86) for the visa-a score in the conservatively treated group, compared to 78.0 (sd = 24) and 78.5 (sd = 12.02) in the surgically treated group. isokinetic strength ranged from 13.8 to 144.3 n/kg in both groups combined. the mean lsi for endurance testing was 60 (sd = 7.07) for the conservative group and 70.45 (sd = 26.09) for the surgical group. range of motion in dorsiflexion was consistently higher in 32 s af. j sports med vol. 28 no.2 supplement 2016 the treated leg in all subjects. tendon length and global strain were similar between groups. overall, there were no statistically significant differences between groups. conclusion: these preliminary results are in line with those in literature, where symptoms and functional outcome after tendon rupture is similar for conservative versus operative treatment including mechanical tendon behavior. the comparable strain results in the conservative group justify further investigation on a larger group to increase the power of this biomechanical analysis of atr. given the higher risk of complications with surgery, this may provide further evidence that achilles tendon ruptures can be treated conservatively. p37: modulation on tendon vascularization is associated with pain in athletes with patella tendinopathy after 12-week of eccentric exercise combined with extracorporeal shockwave therapy wc lee 1 , zj zhang 2 , l masci 3 , gyf ng 1 , sn fu 1 , 1 department of rehabilitation sciences, the hong kong polytechnic university, hong kong (sar), china, 2 department of physical therapy, henan provincial orthopaedics hospital, henan, china, 3 pure sports medicine, london, united kingdom presenting author e-mail address: amy.fu@polyu.edu.hk introduction: decrease in tendon vascularization was observed in subjects being successfully treated with exercise 1 and extracorporeal shockwave therapy (eswt) 2 . it is unclear whether combining both interventions would enhance the treatment-induced effect. methods: thirty-three male basketball, volleyball, and handball players (mean age=22.8±4.0 years) with patellar tendinopathy for more than 3 months (mean 33.0±26.3 months) participated in the study. subjects were randomized into exercise and combined groups. the exercise group received a 12week single-legged decline-squat exercise and the combined group had a similar exercise programme in addition to 6 weekly sessions of extracorporeal shockwave therapy (eswt) in the initial 6 weeks of the exercise programme. tendon vascularization of the patellar tendon was examined using power doppler ultrasonography. the intensity of vascularization determined by the percentage of colour pixels was expressed as vascular index (vi). the intensity of maximal selfperceived pain on past 7 days was enquired using visual analogue scale (vas). these parameters were measured at pre, post intervention and 6-week post intervention. results: twenty-nine subjects completed the programme. repeated measures anova on tendon vi indicated significant time effect (p=0.024), significant main effect on pre-intervention vi (p=0.000) and time* pre-intervention vi interaction (p=0.004) on the changes of tendon vascularity. no significant group effect was detected (p=0.471). there was a significant reduction of the intensity of pain from (from 6.4±2.0 to 2.6±1.6, p=0.000) at 6-week post intervention. partial correlation test was conducted with pre-intervention vi and side of affected knee as control variables. significant correlation was detected between the change in tendon vi and the reduction in pain at post-intervention (r=-0.70, p=0.017) and 6-week post-intervention (r=-0.83, p=0.001) in the combined group. discussion: modulation on tendon vascularity depends on pre-intervention vascularization. addition of eswt could not enhance the change of tendon vascularity and pain. the reduction in tendon vascularity, however, is related to the reduction in pain in the combined group. our findings support the notion that reduction in tendon vascularization is one of the treatment mechanisms for subjects receiving eswt and eccentric exercise. references: 1. kongsgaard m, kovanen v, aagaard p, doessing s, hansen p, laursen ah, kaldau nc, kjaer m, magnusson sp. corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy. scand j med sci sports 2009. 19(6):790-802. 33 s af. j sports med vol. 28 no.2 supplement 2016 2. notarnicola a, moretti l, tafuri s, forcignano m, pesce v, moretti b. reduced local perfusion after shock wave treatment of rotator cuff tendinopathy. ultrasound med biol. 2011;37(3):417-425. p38: a preliminary exploration of somatosensory and psychological characteristics in a severe subgroup of individuals with lateral epicondylalgia v vuvan 1 ; r mellor 1 ; l heales 3 ; b coombes 1 ; p hodges 1 ; m farrell 2 ; and b vicenzino 1 1 school of health and rehabilitation sciences, the university of queensland, brisbane, australia, 2 school of biomedical sciences, monash university, clayton, australia, 3 school of human, health and social science, division of physiotherapy, central queensland university, rockhampton, australia presenting author e-mail address: v.vuvan@uq.edu.au introduction: one of the challenges in the management of lateral epicondylalgia (le) is the varying prognoses of individual patients. previous post-hoc analyses of clinical trials indicate that there might be a characteristic somatosensory profile that identifies a severe subgroup and predicts those with a poor outcome. the aim of this study was to investigate the somatosensory and psychological characteristics that might characterise le subgroups on the basis of their severity of pain and disability as scored by the patient rated tennis elbow evaluation (prtee). methods: forty-six participants (mean age 46 years, 23% female) with a primary clinical diagnosis of le were sub-grouped into mild (23), moderate (17) and severe (5) on the basis of a previous cluster analysis using the prtee. thirteen healthy controls (mean age 48 years, 39% female) also participated. thermal and mechanical detection and pain thresholds, vibration threshold, and pain sensitivity to sharp and blunt mechanical stimuli were evaluated at the lateral epicondyle and infrapatellar pole. temporal summation of heat pain was measured at the hand. the paindetect, neck disability index, health-related quality of life, hospital anxiety and depression scale, tampa scale of kinesiophobia, pain catastrophising scale and pain self efficacy questionnaire were also collected. results: the severe le subgroup showed lower mechanical detection threshold at the elbow compared to healthy controls (p<0.05). increased temporal summation of heat pain and paindetect scores were found in the severe le subgroup compared to the mild le subgroup (p<0.01). discussion: findings from this preliminary study suggest that individuals with severe le might be differentiated by increased sensitivity to light touch at the elbow and enhanced temporal summation. whilst a lower paindetect score (≤12) suggests nociceptive pain may be the main mechanism in individuals with mild le, the results for individuals with severe le are unclear, however infer a component of neuropathic pain (paindetect score 13-18) might be present within this subgroup. p39: patient characteristics associated with the severity of pain and disability of gluteal tendinopathy ml plinsinga 1 ; bk coombes 2 ; r mellor 1 ; p nicolson 5 ; a grimaldi 3 ; j wajswelner 4 ; p hodges 1 ; k bennell 5 ; and b vicenzino 1 1 university of queensland, school of health and rehabilitation sciences: physiotherapy, university of queensland, st lucia, brisbane, australia, 2 university of queensland, school of biomedical sciences, st lucia, brisbane, australia, 3 physiotec, 23 weller road, tarragindi, qld 412, australia, 4 department of physiotherapy & lifecare physiotherapy, latrobe university, bundoora, australia, 5 centre for health, exercise and sports medicine, department of physiotherapy, university of melbourne, carlton, australia presenting author e-mail address: m.plinsinga@uq.edu.au introduction: gluteal tendinopathy is a prevalent condition among middle-aged females, impacting on daily activities, work and quality of life. the primary aim was to describe a broad range of physical 34 s af. j sports med vol. 28 no.2 supplement 2016 and psychological health characteristics of patients with gluteal tendinopathy and to determine relationships with severity of pain and disability. methods: 203 participants (mean age 54.8 years, range 35-71, 82% female) meeting a clinical diagnosis of gluteal tendinopathy with mri confirmation were included in this study. 77% had unilateral pain, and 23% bilateral. measures were anthropometric (bmi, waist girth, hip circumference, waist-hip ratio (whr)), physical (hip abductor muscle strength) and questionnaires (visa-g, active australia survey, pain catastrophizing scale (pcs), the pain self-efficacy questionnaire (pseq), health-related quality of life (eq-5d)). cluster analysis of the visa-g scores (range 0-100, 100=no pain and disability) classified participants into mild, moderate and severe pain and disability. an ancova was performed to evaluate whether characteristics differed between subgroups based on severity, including sex as a covariate, followed by bonferroni post-hoc tests. significance was set at 0.01. results: cluster analysis of the visa-g identified three subgroups: mild (n=51; mean 76.5; range 6898), moderate (n=103; mean 59.0; range 51-67) and severe (n=49; mean 42.7; range 14-50), supported by a corresponding and incrementally greater average/worst pain (p≤0.001). pain catastrophizing scores and pain self-efficacy scores were significantly different between groups (p<0.001), post hoc analysis revealed greater pain catastrophizing and a lower pain self-efficacy in the moderate and severe groups than the mild group. higher scores on vigorous activity (md 131.82 minutes; 95%ci 32.38, 231.26; p=0.005) and quality of life (md 0.123; 95%ci 0.047, -.198; p<0.001) were reported for the mild group than the severe group. hip abductor muscle strength, waist girth and whr differed between sexes (p<0.001) but not sub-groups differences; values for these parameters were greater for men than women. discussion: individuals with greater severity of pain and disability accompanying their gluteal tendinopathy present with lower pain self-efficacy, higher pain catastrophizing, lower vigorous activity levels, and lower quality of life than those with less severe symptoms. future research would benefit from consideration of both psychological and physical assessments and interventions. p40: increase in tendon strain is associated with pain reduction after 12-week eccentric exercises in jumping athletes with patella tendinopathy sn fu 1 , wc lee 1 , zj zhang 2 , l masci 3 , gyf ng 1 1 department of rehabilitation sciences, the hong kong polytechnic university, hong kong (sar), china, 2 department of physical therapy, henan provincial orthopaedics hospital, henan, china, 3 pure sports medicine, london, united kingdom presenting author e-mail address: amy.fu@polyu.edu.hk introduction: strength training that induces mechanical loading on the tendon and alters its mechanical properties. these changes have been reported in healthy 1 but scarce information is on pathologic tendons. whether a change in tendon mechanical properties would relate to reduction in pain is not known. methods: thirty-five male basketball, volleyball and handball players (mean age=22.4±4.0 years, 16 had unilateral symptoms) with tendinopathy for more than 3 months (mean 31.9±25.4 months) participated in the study. subjects were randomized into exercise and combined groups. the exercise group received a 12-week single-legged decline-squat exercise and the combined group had a similar exercise programme in addition to 6 weekly sessions of extracorporeal shockwave therapy (eswt) in the initial 6 weeks of the exercise programme. tendon strain of the patellar tendon was examined using ultrasonography and dynamometry. the intensity of maximal self-perceived pain over 7 days was enquired using visual analogue scale (vas). these parameters were measured at pre and postintervention. results: thirty-one subjects (15 with unilateral symptom) completed the treatment programme. repeated measures anova indicated significant time effect (all p<0.05) but not significant group effect (all p >0.05) on the outcome measures. significant increase in tendon strain (from 10.5±4.1% to 35 s af. j sports med vol. 28 no.2 supplement 2016 13.1±5.3%, p=0.08), and reduction of intensity of pain (from 6.5±2.0 to 3.5±2.1, p=0.00) were observed at post-intervention. partial correlation test was conducted with sports and side of affected knee as control variables. a significant correlation was detected between the reduction in perceived pain and the increase of tendon strain (r=0.82, p=0.003) in the exercise group. no significant correlation was found in the combined group. discussion: 12-week of eccentric exercise induced increase of tendon strain in athletes with patellar tendinopathy. the increase in tendon strain is related to the reduction in pain. our findings suggest that eccentric exercise programme could modulate tendon mechanical properties and such change is associated with the reduction of pain in athletes with patellar tendinopathy. references: 1. reeves nd, maganaris cn, narici mv. effect of strength training on human patella tendon mechanical properties of older individuals. j physiol 2003;548:971-81. 2. kubo k, kanehisa h, fukunaga t. effects of different duration isometric contractions on tendon elasticity in human quadriceps muscles. the journal of physiology 2001;536(pt 2):649-655. p41: taping facilitates scapular kinematics and activity onset of scapular muscles in athletes with rotator cuff tendinopathy ht leong 1 , gyf ng 1 , sn fu 1 1 department of rehabilitation sciences, the hong kong polytechnic university, hong kong (sar), china presenting author e-mail address: annieleonght@gmail.com introduction: athletes with rotator cuff tendinopathy demonstrated abnormal scapular motion and activity onset of scapular muscles during arm elevation. the aim of this study is to examine the effect of scapular taping on the kinematics and activity onset of scapular muscles in athletes with rotator cuff tendinopathy. methods: twenty-six male volleyball players with rotator cuff tendinopathy (mean age=23.6±3.3 years) participated in the study. three-dimensional scapular kinematics was quantified using an acromial marker cluster method, and electromyography (emg) activity onset of upper, middle and lower trapezius and serratus anterior during shoulder abduction were compared with three scapular taping protocols, namely, no taping, therapeutic taping, and placebo taping. 1 results: there were significant increases in scapular upward rotation from 0° to 30° (7.16±2.34° vs. 6.40±2.16°, p=0.007), and from 60° to maximum shoulder abduction (27.27±6.08° vs. 24.93±6.11°, p=0.019) when therapeutic taping and no taping conditions were compared. no significant effect of taping was found on posterior tilting (p=0.379) and external rotation (p=0.131). placebo taping demonstrated no effect on any scapular motions (all p>0.263). the middle and lower trapezius, and serratus anterior fired earlier in both therapeutic taping (all p<0.005) and placebo taping conditions than no taping conditions (all p<0.002). discussion: scapular taping modulates the scapular kinematics in athletes with rotator cuff tendinopathy by providing mechanical support and neuromotor facilitation of the scapular muscles during dynamic arm abduction. scapular taping with full tension can effectively increase scapular upward rotation in the early phase of abduction from 0° to 30° and in the late phase from 60° to maximum abduction. scapular taping with or without tension can hasten the activity onset of scapular muscles during dynamic arm abduction. based on our findings, scapular taping with tension is suggested for athletes with rotator cuff tendinopathy to enhance the neuromotor control of the scapular muscles and to provide mechanical support for normal scapular kinematics during arm movement. . references: 1. cools am, witvrouw ee, danneels la, cambier dc. does taping influence electromyographic muscle activity in the scapular rotators in healthy shoulders? man ther 2002;7(3):154-162. km_c227-20180511093520 original research 112 sajsm vol. 24 no. 4 2012 background. the global mandate by the who world health report of 2002, global strategy for diet, physical activity and health, were mirrored by the policy environment in south africa. the ‘vuka south africa – move for your health’ campaign was an example of an initiative adopted by national government, promoting physical activity (pa) for health. methods. this manuscript describes the process, events and lessons learned during the initial phase of vuka sa from 2004 to 2010. data were obtained from the grey literature, minutes and reports of meetings and from stakeholders. results. utilising a multi-sectoral approach, this initiative was partnered by governmental and non-governmental organisations, the private sector and tertiary institutions. the main anticipated short-term outcome was an increased awareness of the message (‘move for your health’), with a view to achieving increased population levels of participation in health-enhancing physical activity over the long term. vuka sa was initiated by the national department of health and launched in 2005. subsequently, 36 partner organisations participated in two national workshops, who together with provincial health promoters undertook to promote the campaign. this was followed by an international training course on pa and public health for policy makers and programme implementers, and the subsequent call for the development of an african physical activity network. discussion. although the campaign has not yet undergone rigorous evaluation and participation at present appears to be modest, there are promising examples of multi-sectoral awareness and advocacy activities resulting in some national dissemination of the role of pa in health promotion. s afr j sm 2012;24(4):112-116. doi:10.7196/sajsm.349 physical activity advocacy and promotion: the south african experience t l kolbe-alexander, f bull, e v lambert uct/mrc research unit for exercise science and sports medicine, faculty of health sciences, university of cape town t l kolbe-alexander, phd e v lambert, phd british heart foundation national centre for physical activity and health, loughborough university, united kingdom and school of population health, university western australia f bull, phd corresponding author: t kolbe-alexander (tracy.kolbe-alexander@uct.ac.za) in 2002, the world health organization’s (who) report on reducing risks and promoting healthy living recognised physical inactivity as one of the major modifiable risk factors for developing non-communicable diseases (ncds) and global mortality and morbidity, along with tobacco use, unhealthy eating and obesity, and excessive alcohol intake.1 consequently, creating a public health message emphasising the benefits of regular physical activity which aimed to promote positive lifestyle and behaviour change became increasingly important. placing this in a south african (sa) context, where there is a quadruple burden of disease, ncds account for more than onethird (37%) of all deaths.2 this is juxtaposed with 57% of sa women and nearly 30% of men who are overweight or obese.2 furthermore, only 36% of sa men and 24% of women report sufficient levels of daily health-enhancing physical activity.3 similarly, the sa youth risk behaviour survey has found that more than one-third of all adolescents report insufficient levels of physical activity.4 moreover, 30% of ischaemic heart disease, 27% of colon cancer, and 20% of diabetes in sa have been attributed to physical inactivity.5 thus, there is a major health imperative to promote physical activity (pa) and reduce levels of inactivity in the general south african population. in the context of global and national trends for rising prevalence of obesity, inactivity and ncd, and in part, in response to the who’s mandate to promote pa and health, the ‘vuka south africa – move for your health’ (vuka sa) campaign was initiated in 2004/2005. the aim of this report is to document the process of developing the vuka sa campaign and to identify factors, including the policy environment, that may have influenced the development and progress of such a campaign in countries like sa, which have important competing health agendas such as hiv/aids, and wide demographic and socioeconomic disparities. we describe the factors influencing the initiation of the vuka sa campaign, to the launch in 2006, and subsequent activities until 2010. methods sources of information data in the form of reports and notes from meetings were obtained from the ndoh’s health promotion unit, provincial department of health’s health promotion officers, grey literature and members of the inter-sectoral vuka sa task team. expected outcomes the vuka sa campaign logic model is presented in fig. 1. the primary expected outcome of the move for health campaign was a greater awareness of the role of pa for promoting health. intermediate mailto:tracy.kolbe-alexander@uct.ac.za sajsm vol. 24 no. 4 2012 113 outcomes included an expanded reach of the message, implementation of supportive policy, changing social norms towards pa, leading to increased participation. description and interpretation of results the formative events and the process of implementation of vuka are reported on, according to the information sources, and have been arranged chronologically. where data on reach and implementation are available, these have been presented. there are no available data on secular trends in population-based pa prevalence. the first time pa was included in a national health survey was in 2004; this is planned to be repeated in 2012, therefore describing the trends in pa for sa is beyond the scope of this paper. results formative global and national policy environment and initiatives (1990s) fig. 2 provides a schematic of the national and global events and chronology leading to the development and launch of the vuka sa campaign. the early-to-mid 1990s in sa were characterised by seminal events, including the abolition of apartheid and the first free national government elections. the eradication of apartheid resulted in the increased equal access to health care, sporting and recreational facilities and education.6 during the same period, public and private sector partnerships governmental and non-governmental organisations (ngos) and tertiary institutions developed and implemented various community-based intervention programmes focusing on the promotion of pa.6,7 there was limited evaluation, programmes often occurred in ‘silos’, and there was an absence of a national, multi-sectoral written plan aimed at improving health status through increased pa among sa. concurrently, pa was receiving increasing global attention and recognition as a modifiable risk factor for ncds in both developed and developing countries. the us surgeon general’s report on physical activity, first published in 1995, advocated the accumulation of 30 minutes of moderate intensity on at least 5 days of the week.8 this recommendation facilitated the development of a unified message for the prescription of pa for health. in response to this global trend, and due to the high prevalence of inactivity and ncds, agita sao paulo was launched in 1996 in the state of sao paulo, brazil.9 this programme was initiated by a non-governmental research and teaching institute based in sao paulo (celafiscs), and was an example of a mass participation campaign advocating 30 minutes of pa at least 5 days per week among brazilians.9 further to the success of agita on a national and regional platform, the who adopted this focus for world health day in 2002, which resulted in the establishment of the agita mundo/move for health, global campaign. the move for health slogan was translated into 63 languages, enabling 148 countries to organise 1 987 events around the world in 2002.10 move for health day (2002) the national department of health (ndoh), together with the local who office, were the driving forces behind the 2002 move for health campaign. the main national event in 2002 took place in the fig. 1. logic model of vuka south africa – move for your health. 114 sajsm vol. 24 no. 4 2012 gauteng province and was comprised of a street parade, followed by formal speeches by government officials. this event also focused on community participation in recreational activities including indigenous games and dancing, which were organised by the national department of sports and recreation.11 in other provinces, local departments of health hosted free health screening and pa promotions for their employees, and communities were encouraged to support and stage local events. the main focus of these events was to celebrate and encourage participation in pa. unfortunately, at the time of implementation, monitoring and evaluation received little attention, and the exact number of events and participants are unknown. healthy lifestyles campaign (2004 2007) subsequent to move for health day (2002), the ndoh’s healthy lifestyles campaign was launched. this campaign formed part of the national plan for comprehensive health care in sa, and was one of the strategic priorities for the period 2004 2009.12 the campaign had five main pillars, which included promotion of pa, healthy nutrition, tobacco control, responsible sexual behaviour and combatting the abuse of alcohol. programmes and activities included routine 2 5-km walks within strategically selected communities. this was followed by mass public preventive health-risk screening. the context of the ‘healthy lifestyles’ days provided opportunities to promote regular pa and ongoing dissemination of the important message ‘move for your health’. approximately 2 400 adults were screened and participated in these events annually (2004 2007). operationalising vuka sa in response to the who global strategy for diet and physical activity for health, academics approached the ndoh’s health promotions unit in february 2005, highlighting the importance of implementing a ‘move for health day’ campaign in sa. government officials were receptive to the message, which was compatible with the ‘healthy lifestyles’ campaign. two meetings followed to discuss potential strategies to promote this campaign to other stakeholders and service providers in sa. following these meetings, the ndoh invited other governmental departments, ngos, tertiary institutions and representatives from the private sector to be part of a task team. t he i n it i a l te am w as c ompr is e d of fou r gove r n me nt a l departments (health, sport and recreation, education, social services), five ngos, four companies from the private sector and one tertiary institution. the task team met on six occasions at the ndohs offices and held a number of teleconferences between february and may 2005. the main agenda items for these meetings were to (i) explore the nature and feasibility of the campaign; (ii) plan the introduction of vuka sa to the national parliament; and (iii) plan the launch of the campaign. one of the first and most important decisions reached by the task team was that ‘move for your health’ would not be restricted to one day’s celebrations, but should be ongoing promoting the benefits of pa. secondly, the campaign was branded ‘vuka sa – move for your health’ and was to form part of the ndoh’s healthy lifestyles initiative. vuka is the nguni (indigenous sa language) word for ‘wake fig. 2. schematic of the development of the vuka south africa – move for your health campaign: 1994 2008. sajsm vol. 24 no. 4 2012 115 up’. thus, the campaign aimed to ‘wake the nation up’ to become more physically active and to promote healthy lifestyles. political commitment another pre-requisite for implementing successful national plans for physical activity is a high level of political commitment.13,14 in the 2005 budget speech to the national parliament, the minister of health highlighted the burden of ncd in sa, and the importance of healthy lifestyles, including regular pa, for the prevention and management of these conditions.15 prior to the budget speech, the minister participated in a march through the cape town central business district to parliament, together with members of the community. several hundred participants carried posters and banners advocating pa. this action received national television coverage, including the minister’s call to become more physically active. in this way the general public, together with parliamentarians, were first introduced to vuka sa in april 2005. these factors, together with the global focus on pa for health, provided a window of opportunity for physical activity advocacy in sa. consistent message based on the media exposure obtained at the minister of health’s budget speech and advocacy by members of the task team, individuals who were interested in becoming part of vuka sa were provided with an information booklet. this booklet detailed the background of ‘move for health’ from the who, the rationale for the campaign and a guide to implementation. task team members subsequently distributed the booklet among their constituencies, along with an additional 30 individuals and organisations, who requested copies for distribution. furthermore, the ndoh distributed the booklet to all their provincial offices to promote local events to support the campaign. each provincial office played a role in disseminating the booklet to their stakeholders, including community health centres and schools. therefore, a consistent and clear message was disseminated, ensuring that all stakeholders were promoting 30 minutes of pa on at least 5 days per week. launch of vuka sa the official launch of the campaign took place in may 2005 in alexandra township, a high-population density and low socioeconomic community in gauteng province, near johannesburg. similar to the healthy lifestyles campaign, the vuka sa launch began with a 4 km walk, led by the minister of health and representatives from the departments of education and sport and recreation. about 1  000 adults and children participated in health screening and in various sporting and physical activities at the stadium. the media had a strong presence and the minister of health, representatives from the who in-country office, tertiary institutions, ngos, the national department for education and members of the public were interviewed during the morning’s television broadcast. vuka sa activities were also implemented by the provincial departments of health and these local events allowed for broader dissemination of the campaign message.16 vuka sa workshop the aim of the launch was to disseminate the vuka sa message. however, baumann et al. have shown that mass media campaigns are generally more successful if there is a downstream community component.17 in this case, a workshop was subsequently held for pa practitioners interested in promoting pa for health. invitations were sent to ngos and health promotion officers from the provincial departments of health. two workshops were arranged by the task team, and co-funded by the private healthcare sector. the first one was for decision makers and managers, and the second for teachers, coaches and health workers responsible for implementing community-based programmes and promoting regular pa. the main aims of the workshops were to provide delegates with practical advice to promote and implement vuka sa in their constituencies. positioning the workshops together with a national sports medicine conference allowed the task team to attract more delegates. the 150 delegates were divided into four discussion groups around: • factors affecting the implementation of programmes promoting pa • the need for evaluating the impact and effectiveness of these programmes • opportunities for working with other themed initiatives within the ndoh • how to best integrate initiatives from different sectors to prevent duplication and to maximise the reach of the message. television and written media representatives were present and conducted interviews with the minister of health and workshop attendees, and were aired on the afternoon news bulletin that same day.18 international physical activity and public health course (ipaph) following the workshop, and with a view to increasing national and regional capacity for implementation and evaluation of physical activity programmes for health, the first international course for physical activity and public health in africa was held in march 2007, through the cooperative agreement between the us centers for disease control and prevention (cdc) and the international union of health promotion and education, and in conjunction with the university of cape town.19 the 3.5-day curriculum was designed to aid pa practitioners, advocates, epidemiologists, public health and health promotion specialists, physical educationalists, policy makers and programme directors, concerning all issues related to physical activity and public health, with a specific focus on surveillance, policy development, interventions and evaluation. attendees included more than 40 representatives from the private sector, ngos, tertiary institutions and governmental departments. in addition, representatives from other african countries, nigeria, uganda, zambia, kenya, côte d’ivoire, tanzania and botswana were also in attendance. an important outcome of the course was the interest expressed in developing an african network related to pa and public health. african physical activity network (afpan) subsequent to the ipaph course, the african physical activity network (afpan) was formed. afpan aimed to establish a network of organisations from various sectors, across africa, with the common goal of increasing the population prevalence of pa. the primary aim was to share experiences and pa advocacy, and to provide a platform for new regional projects and initiatives. in addition, it was envisaged that the sharing of programmes and lessons learnt would strengthen 116 sajsm vol. 24 no. 4 2012 existing initiatives and also lead to the development of best-practice models which were relevant to the african continent. afpan made limited progress between 2007 and 2009, due in large measure to limited resources. however, in april 2010 a programme coordinator was appointed by a tertiary academic institution, which revived the nascent network. subsequently the afpan website was created (www.essm.uct.ac.za/afpan/index.htm), newsletters were sent to members representing 11 african countries (between 2010 and 2011), and a pa policy audit among african countries was initiated. this network is part of the global alliance for physical activity (gapa). vuka sa: 2007 2010 subsequent to the launch in 2005 and the workshop in 2007, there have been continued activities and events linked to vuka sa. however, these have been sporadic and limited data are available on the reach of these activities. examples of events include the sa pharmacy council linking pharmacy week in 2007 with vuka sa. provincial activities such as the 2008 gauteng vuka sa sports day have also been sustained. other initiatives include the don locke fun run, which has adopted move for health as its theme, and had approximately four schools participating in 2006 and more than 40 schools in 2010, in the western cape province. discussion vuka sa provided an opportunity for various governmental departments and stakeholders to work together with the aim of increasing south africans’ levels of pa. the launch and subsequent workshops functioned as a platform for the sustained implementation of the campaign. however, the implementation has been sporadic since 2007. monitoring and evaluation of vuka sa activities have not been systematic and are limited, and as a result there are no current measures of national or regional reach and impact. achievements the ndoh’s healthy lifestyles campaign provided a vehicle to promote regular pa at a provincial and national level. provincial health promotion departments have continued to implement vuka sa-linked activities since the launch in 2005. for example, the western cape and gauteng provinces trained health workers in the benefits of pa and leading pa sessions at the local health care centres. however, it should be recognised that the extent to which programmes have been implemented varies from province to province, with some having very few activities. the establishment of partnerships between governmental, ngos, the private sector and tertiary institutions was at least partially successful. in sa, private companies contributed towards the cost of launching the campaign and the workshops which were attended by stakeholders, representing a broad range of interests. challenges there was no consultative national plan for the promotion of pa throughout this process, although there was tacit support for such a plan from various stakeholders. the development of national policies and setting programme goals for a predetermined time period have been identified as important components of promoting populationbased pa programmes.14 government is perhaps best placed to facilitate the development and implementation of these national plans.14 there is a need for evaluation of this and other pa and health initiatives ─ through evaluation of existing programmes there may be an opportunity to generate practice-based evidence. summary the vuka sa campaign was initiated in 2005 and despite some difficulty gaining momentum and reach, progress was made. the media were receptive to providing coverage, thereby providing opportunities for increased awareness for the pa and health message. this message was well received and has enjoyed inter-sectoral collaboration between governmental, ngo, private companies and tertiary institutions. the future of the campaign involves the development of a consultative national plan for pa, which is currently under way, and generating a stronger and unified message to the sa public to raise awareness and increase the prevalence of pa. research measuring the effectiveness of the various messages and events associated with promoting health through pa in sa, towards changing knowledge, attitudes and behaviour will be undertaken. acknowledgements. the authors would like to acknowledge the support for vuka sa from the national departments of health, education, sport & recreation, and social development. we would also like to thank mr n ntuli from the ndoh for providing some insight during the preparation of this manuscript. references 1. campanini b, ed. who report 2002. reducing risks promoting healthy life. geneva: world health organization, 2002. 2. bradshaw d, groenewald p, laubscher r, et al. initial burden of disease estimates for south africa, 2000. s afr med j 2003;93(9):682-688. 3. guthold r, ono t, strong kl, chatterji s, morabia a. worldwide variability in physical inactivity a 51-country survey. am j prev med 2008;34(6):486-494. 4. reddy sp, swart d, jinabhai cc, et al. umthenthe uhlaba usamila – the south african youth risk behaviour survey 2002. cape town: south african medical research council, 2003. 5. joubert j, norman r, lambert ev, et al. estimating the burden of disease attributable to physical inactivity in south africa in 2000. s afr med j 2007;97(8 pt 2):725-731. 6. government gazette sa. national sport and recreation act 19551, 1998. 7. boshoff g. barefoot sports administrators: laying the foundations for sports development in south africa. journal of sport management 1997;11:10. 8. martin sb, morrow jr, jr., jackson aw, dunn al. variables related to meeting the cdc/acsm physical activity guidelines. med sci sports exerc 2000;32(12):2087-2092. 9. matsudo v, matsudo s, andrade d, et al. promotion of physical activity in a developing country: the agita sao paulo experience. public health nutr 2002;5(1a):253-261. 10. world health day 2002: move for health. http://www.who.int/world-health-day/ previous/2002/en/ (accessed 1 january 2011). 11. minister of health. speech given during the world health day celebration. http:// www.doh.gov.za/docs/sp/2002/sp0407.html (accessed 1 january 2011). 12. steyn kfj, temple n. chronic diseases of lifestyle in south africa, 1995 2005. in: physical activity and chronic diseases of lifestlye in south africa. cape town: south african medical research council, 2006. 13. magnusson r. non-communicable diseases and global health governance: enhancing global processes to improve health development. global health 2007;3(2). 14. bull fc, pratt m, shephard rj, lankenau b. implementing national population-based action on physical activity--challenges for action and opportunities for international collaboration. promot educ 2006;13(2):127-132. pmid:17017290. 15. minister of health. budget speech, 2005. http://www.doh.gov.za/show.php?id=937 (accessed 1 january 2011). 16. tshabalala-msimang m. statement on the move for health launch press conference, 2005. http://www.doh.gov.za/show.php?id=923 (accessed 1 january 2011). 17. bauman ae, nelson de, pratt m, matsudo v, schoeppe s. dissemination of physical activity evidence, programs, policies, and surveillance in the international public health arena. am j prev med 2006;31(4):s57-65. 18. tshabalala-msimang m. speech at the move for health national workshop, 2005. http://www.doh.gov.za/show.php?id=899 (accessed 1 january 2011). 19. international physical activity and public health course. http://www.essm.uct.ac.za/ health_pubhealth.html (accessed 1 august 2012). http://www.essm.uct.ac.za/afpan/index.htm http://www.who.int/world-health-day/ http://www.doh.gov.za/docs/sp/2002/sp0407.html http://www.doh.gov.za/docs/sp/2002/sp0407.html http://www.doh.gov.za/show.php?id=937 http://www.doh.gov.za/show.php?id=923 http://www.doh.gov.za/show.php?id=899 http://www.essm.uct.ac.za/ km_c227-20180517092740 c p d q u e s t io n n a ir e instructions 1. read the journal. all the answers will be found there. 2. go to www.cpdjournals.co.za to answer questions. accreditation number: mdb001/025/10/2011 (clinical) sajsm questions june 2012 cpd questionnaires must be completed online via www.cpdjournals.co.za. after submission you can check the answers and print your certificate. 1. true (a) or false (b): the 2007 american college of sports medicine position stand on exercise and fluid replacement warns athletes not to lose >2% body weight during exercise as it may adversely affect performance. 2. true (a) or false (b): the fastest runners in a marathon usually lose the least weight during a race. 3. true (a) or false (b): signs and symptoms of hyponatraemia include nausea, vomiting, confusion, and headache. 4. true (a) or false (b): runners who become dehydrated during a race, face the risk of hyponatraemia. 5. true (a) or false (b): compared with other countries, there is a very high incidence of hyponatraemia in marathon runners in south africa. 6. true (a) or false (b): t ere are several validated questionnaires for the purpose of measuring and reporting physical activity levels in south african children. 7. true (a) or false (b): te average energy expenditure of south african children is about 1 200 cal/day. 8. true (a) or false (b): in the absence of either medical or obstetric complications, all pregnant women should be encouraged to participate in aerobic and strength-conditioning training at a moderate intensity, on most, if not all, days of the week. 9. true (a) or false (b): pelvic floor exercises in the immediate post-partum period may reduce the risk of future urinary incontinence. 10. true (a) or false (b): vitamin d can be absorbed throughout the year in the united kingdom. 11. true (a) or false (b): dark-skinned individuals usually have high levels of vitamin d production. 12. true (a) or false (b): in addition to melanin content, social behaviours such as sun exposure and clothing should also be considered when reviewing an athlete’s risk of developing vitamin d deficiency. 13. true (a) or false (b): te application of sun cream does not increase the risk of developing vitamin d deficiency. 14. true (a) or false (b): popliteal artery entrapment syndrome (paes) is a very common cause of exercise-induced pain in the lower extremity of young athletes. 15. true (a) or false (b): paes is a partial or complete occlusion of the popliteal artery as a result of aberrant anatomy in the popliteal fossa. 16. true (a) or false (b): paes usually affects females older than 65 years. 17. true (a) or false (b): players of rugby union have a risk of injury of about 2 injuries per 1 000 hours of exposure. 18. true (a) or false (b): te risk of injury in rugby union decreases with increasing age and level/grade. 19. true (a) or false (b): nearly all the players who were injured at the youth rugby tournaments had medical insurance. 20. true (a) or false (b): whole body vibration (wbv) is a current neuromuscular training method, which even at a low intensity provokes muscle length changes that stimulate the sensory receptor of the muscle spindle. original research 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license negative self-appraisal mediates the relationship between mindfulness and confidence among adolescent female provincial hockey players in south africa s walker, phd unit for professional training and services in the behavioural sciences (unibs), university of the free state, bloemfontein, south africa corresponding author: s walker (walkersp@ufs.ac.za) mindfulness is perhaps most often thought of as awareness of the present moment characterised by an accepting and nonjudgemental orientation towards external stimuli and internal experiences.[1] dispositional mindfulness (dm) has been defined as an innate and relatively stable focus and quality of attention that is distinct from other forms of mindfulness and is associated with, yet conceptually unique from, various personality traits.[2] dm has been associated with improved or superior performance in a number of sports.[3] dm also appears to promote emotional resilience and well-being among athletes. for example, a negative association has been found between sport-related burnout and dm among competitive youth tennis players.[4] despite this growing body of literature on dm in sport and performance psychology, little is known about its mechanisms of impact. it has been theorised that mindfulness facilitates improved athletic performance by way of attentional awareness, experiential acceptance, cognitive flexibility and emotional regulation.[5-6] athletes with higher levels of dm are hypothesised to be more proficient at adopting a nonjudgemental stance toward their inner experiences and physical performance. in addition, dm is thought to facilitate improved performance by promoting adaptive and flexible patterns of thinking.[5] a recent study demonstrated that athletes who reported higher levels of dm were better at regulating their emotions and less inclined to engage in unproductive, repetitive thought.[6] this, in turn, was associated with improved sport-specific coping. based on the above discussion, further exploration of the mechanisms by which dm may impact upon specific performance-related psychological constructs appears warranted. the research on dm and specific performance-related constructs such as mental toughness, (mt) is in its infancy. however, dm has been positively associated with mt in female adolescent hockey players.[7] notwithstanding conceptual debates regarding the precise nature of the construct, a number of theorists regard confidence or self-efficacy as an integral component of mt.[8-9] in addition, confidence has long been considered critical to success in competitive athletics.[10] confidence is viewed as being central to not only the precise execution of sport-specific skills, but to the development of fundamental movement skill proficiency among adolescents.[11] given the apparent importance of confidence in the acquisition of basic athletic competencies and the execution of advanced skills, it seems logical to explore the contribution that mindfulness might make to confidence. moreover, the importance that athletes and coaches place on confidence suggests that interventions directly linked to this particular construct would be more readily accepted and applied in competitive sports settings. within the context of mt, confidence is viewed as an athlete’s belief in their ability to effectively cope with and overcome challenges in their sport.[9] this conceptualisation of confidence seems to be primarily informed by theories on cognitive appraisal and coping.[12-13] confidence could thus be viewed as an individual’s subjective appraisal of their ability to successfully meet a specific challenge. such appraisals are influenced by beliefs that individuals hold about themselves, others and the world. individual’s appraisals of their ability to deal with challenges are most functional when they are based on the accurate interpretation of information in a specific situation.[12] less confidence-consistent beliefs tend to be rigid and absolutistic. a tendency to view oneself as defined in background: mounting evidence suggests that mindfulness is positively related to athletic performance and athlete wellbeing. however, few attempts have been made to explore the psychological processes by which mindfulness might impact performance. objective: to determine whether negative self-appraisal mediates the relationship between dispositional mindfulness and the confidence component of mental toughness among provincial adolescent female hockey players in south africa. methods: provincial adolescent female hockey players (n=486) completed measures of dispositional mindfulness, mental toughness-related confidence and negative self-appraisal. correlation coefficients were calculated between all variables included in the study. an ordinary least-squares regression analysis was performed to test the indirect effect of negative self-appraisal on the relationship between dispositional mindfulness and confidence. results: negative self-appraisal exhibited an indirect effect on the relationship between dispositional mindfulness and the confidence component of mental toughness ( = .06, se = .0, ci95 = .04, .09). a subsequent soble test confirmed that negative self-appraisal served as a statistically significant mediator ( = .06, se = .01, z = 5.76, p = .001) in the model. furthermore, 78.3% of the variance in the effect of dispositional mindfulness on the confidence component of mental toughness was accounted for by negative self-appraisal. conclusion: the effect of dispositional mindfulness on the confidence component of mental toughness among adolescent athletes is mediated by negative self-appraisal. based on the current findings, dispositional mindfulness may foster confidence by lessening the impact of rigid negative appraisals of one’s performance and worth as an athlete. keywords: dispositional mindfulness, mediation s afr j sports med 2019;31:1-5. doi: 10.17159/2078-516x/2019/v31i1a4371 http://dx.doi.org/10.17159/2078-516x/2019/v31i1a4371 https://orcid.org/0000-0002-2110-7881 original research sajsm vol. 31 no. 1 2019 2 totality by successes and failures stems from rigid selfappraisal beliefs which are inconsistent with developing a sense of confidence in one’s abilities.[13] adolescents are generally considered to be at increased risk of low self-confidence, partially as a result of an increased susceptibility to overly rigid and critical self-appraisal.[13-14]. it has also been suggested that female adolescent athletes frequently find themselves in contexts which might influence or promote negative self-appraisal.[15] female adolescents thus seem to be at an increased risk of engaging in rigid and overly critical self-appraisal. this, in turn, could be hypothesised to lead to a decrease in certain components of mt when related in this athlete population. consequently, the association between dm and mt demonstrated in certain adolescent female athlete populations might be effected via self-appraisal beliefs.[7] in other words, negative self-appraisal may mediate the relationship between dm and the confidence component of mt in this population. the current study aims to investigate this hypothesis in a sample of adolescent female provincial hockey players. methods participants the relevant institutional body granted ethical clearance for the study. the south african hockey association granted permission for data to be collected at annual female under-16 and under-19 interprovincial tournaments. informed consent was obtained from all participants, as well as from the guardians of all minors, prior to data collection. participants completed the measures listed below between games or in the evenings. four hundred and eighty-six adolescent female provincial hockey players consented to participate in the study. the average age of the participants was 16.2 years (sd  2.5). participants reported having competed in an average of 2.4 interprovincial tournaments (sd  1.4). six percent of the sample had previously been selected for a south african hockey team at age group level. measures dm was measured using the child and adolescent mindfulness measure (camm).[16] this 10-item self-report inventory requires respondents to endorse response options along a five-point likert-type scale anchored by “never true” and “always true”. the camm yields a unitary mindfulness score, with higher scores indicative of higher levels of dm. acceptable internal reliability has been reported for the camm in this population.[7] to date, no measure of mt appears to have been developed specifically for use amongst adolescents or to have been normed in this population. consequently, the current study employed the confidence scale of the sport mental toughness questionnaire (smtq) in order to measure this component of mt.[8] response options ranging from “not at all true” to “very true” are presented along a four-point likert-type scale. the scale is scored by summing responses across the six items. higher scores indicate increased confidence. despite being developed for use among adults, the confidence scale of the smtq has demonstrated acceptable internal consistency in female adolescent athletes.[7] the self-downing factor identified on the revised version of the child and adolescent scale of irrationality (casi-r) was employed as a measure negative self-appraisal.[17] this factor is composed of eight items. response options are presented along a five-point likert-type scale anchored by “strongly disagree” and “strongly agree”. the casi-r is scored by reversing the rationally worded items and then summing scores across all items. higher scores are indicative of higher levels of irrational and absolutist thinking. the self-downing factor of the casi-r has demonstrated acceptable reliability in a non-clinical adolescent sample.[17] statistical analysis initially, internal reliability coefficients were calculated for all variables included in the study. next, correlations between the camm total score, the casi-r self-downing factor and the smtq confidence scale were calculated. finally, it was hypothesised that negative self-appraisal would mediate (indirect effect) the direct effect of dm on the confidence component of mt (see figure 1). consequently, a mediation analysis was conducted to test for the indirect effect of negative self-appraisal on the relationship between dm and the confidence component of mt. a path-analytic approach using ordinary least–squares (ols) regression analysis was employed for this purpose.[18] the ols regression analysis was performed using the process software macro for spss.[18] the statistical significance of the cross-product of coefficients was tested using a nonparametric bootstrapping method. consequently, no assumptions needed to be made with regard to the distribution of scores in the sample. bias-corrected bootstrap procedures utilising 50 000 simulations were computed for the model. the significance of the indirect effect was determined using a 95% confidence interval. results correlations between the smtq confidence scale, camm and casi-r self-downing factor are displayed in table 1. mean scores, standard deviations (sds) and internal consistency coefficients for each of the measures are also reported. it is table 1. correlations, descriptive statistics and reliability coefficients for the study variables (n=486) variables smtq confidence casi-r sd camm total smtq confidence -0.39** 0.11* casi-r sd -0.324**  0.72 0.81 0.74 m 17.60 18.00 22.19 sd 3.02 5.84 6.05 ** p 0.01; * p 0.05 m, mean; sd, standard deviation; smtq confidence, sport mental toughness questionnaire confidence score; casi-r sd, revised child and adolescent scale of irrationality self-downing factor; camm, child and adolescent mindfulness measure original research 3 sajsm vol. 31 no. 1 2019 apparent from table 1 that all internal consistency coefficients meet the prescribed minimum level of acceptability for noncognitive measures (  .70).[19] a statistically significant (p  .05) positive correlation was found between dm and the confidence component of mt. conversely, negative selfappraisal was significantly (p  .01) and negatively correlated with both dm and the confidence component of mt. given that the three variables of interest were significantly correlated, the proposed mediation model (see fig. 1) could be tested. model coefficients for the mediation analysis are presented in table 2. dm demonstrated a significant negative association with negative self-appraisal (path a) and negative self-appraisal demonstrated a significant negative association with the confidence component of mt (path b) (see fig. 1). the direct effect (path c’) of dm on the confidence component of mt was no longer significant when negative self-appraisal was accounted for. results based on the bias-corrected bootstrap method indicate the indirect effect of negative selfappraisal on the relationship between dm and the confidence component of mt ( = .06, se = .01, ci95 = .04, .09). in addition, the test of the indirect effect based on the sobel test confirms that negative self-appraisal is a statistically significant mediator ( = .06, se = .01, z = 5.76, p = .001) in this model. a total of 78.3% of the variance in the effect of dm on the confidence component of mt was accounted for by negative self-appraisal. discussion an established body of clinical and sports psychology literature implicates rigid and generalised ways of thinking in poor selfconfidence and reduced sporting performance.[9-10, 14] consequently, the current finding that negative selfappraisal demonstrated a significant negative relationship with the confidence component of mt is not surprising. results of the initial correlational analyses also highlighted the positive relationship between dm and the confidence component of mt. this finding is consistent with existing research on the relationship between dm and desirable performance-related psychological processes and states.[3,6-7] more specifically, these findings suggest that confidence may be one mechanism by which dm may impact athletic performance. given the value placed upon confidence by both athletes and coaches, mindfulness-based sport psychology interventions appear to be increasingly deserving of exploration. dm was also found to exhibit a significant inverse relationship with negative self-appraisal. increased levels of dm were associated with a tendency for participants to be less self-critical, less judgemental and less cognitively rigid. this would seem to support the prevailing notion that mindfulness functions to reduce the impact of absolutistic and categorical thinking.[5-6] mindfulness interventions might thus prove a credible alternative to cognitive interventions aimed at reducing the impact of rigid and absolutistic thinking on athletic performance and well-being. at the very least, mindfulness interventions may prove useful adjuncts to cognitive-behavioural sport psychology interventions. for example, dm might foster athletes’ awareness of their tendency towards rigid self-appraisal, as well as tracking the moment-tomoment effect that engaging with these appraisals has on performance.[3,6] the findings discussed above generally reaffirm existing knowledge. the unique contribution of the current study is the exploration of negative self-appraisal as a possible mechanism by which dm might impact the confidence component of mt. of particular interest was the possibility that self-appraisal functioned as a potential cognitive process through which dm fig. 1. negative self-appraisal mediates the relationship between mindfulness and the self-confidence component of mental toughness. ** p 0.01 game b = -1.86** a = -0.03** m = negative self appraisal x = mindfulness y = self-confidence (mental toughness) c' = -0.01 table 2. model coefficients for the mediation analysis (n=486) consequence m (negative self-appraisal) y (confidence component of mt) antecedent coeff. se p f dfs r2 coeff. se p f dfs r2 x (mindfulness) a -0.03 0.00 0.001 56.67 1; 484 0.10 c’ -0.01 0.02 0.70 m (negative selfappraisal) b -1.86 0.21 0.001 44.16 2; 483 0.15 constant i1 2.77 0.11 0.001 i2 21.50 0.75 0.001 f, f-value; coeff, coefficient original research sajsm vol. 31 no. 1 2019 4 impacted confidence, specifically within the context of mt. this was shown to be the case among adolescent female provincial hockey players. self-appraisal mediated the effect of dm on confidence. more specifically, an increase in dm results in a reduction in negative self-appraisal which in turn has a positive effect on confidence. causal conclusions should not be drawn from cross-sectional data. however, it appears that one way in which dm positively impacts confidence among female athletes is by decreasing the frequency and/or intensity of negative self-appraisals. this interpretation would be consistent with theoretical accounts of how dm might impact various aspects of athletic performance.[5-6] current opinion would seem to suggest that mindfulness would not necessarily result in a change in the content or believability of negative self-appraisals that athletes might hold or experience. however, higher dm might be expected to decrease the extent to which athletes engaged with or became attached to any form of self-appraisal.[1,3,6] this implies that dm would be expected to facilitate a more accepting attitude towards rigid negative and positive selfappraisals of athletes’ performance and ability. consequently, dm should not be viewed as a mechanism by which to replace negative self-appraisal with positive self-appraisal, but rather as a means of negating the tendency to cognitively and emotionally over-engage with such self-appraisals. it is important to note the magnitude of the mediation effect that negative-self appraisal has on the relationship between dm and the confidence component of mt. negative selfappraisal accounts for 78% of the variance of the effect of dm on confidence. consequently, in the model that was tested in this study, dm seems to impact the confidence component of mt primarily via negative self-appraisal. this would suggest that any variability in confidence brought about by changes in dm amongst female adolescent hockey players is predominantly the result of changes in the frequency and/or intensity of rigid and absolutistic negative self-appraisal. stated differently, dm seems to influence mt-related confidence predominantly via the intensity, frequency, believability and/or attachment to negative-self appraisal. the utility of mindfulness-based interventions aimed at increasing confidence among adolescent female athletes seems to be justifiable from both mindfulness and traditional cognitivebehavioural paradigms.[5-6, 14] moreover, mindfulness-based interventions might hold promise in non-performance-related areas of female athlete health. many issues relating to body image and eating behaviour have been shown to be largely maintained by pervasive patterns of negative selfevaluation.[15] consequently, if mindfulness interventions are able to impact upon negative self-appraisal, it seems logical that such interventions might prove effective in addressing some of the most disabling mental health issues facing adolescent female athletes. study limitations the current study highlights the potential for dm to mediate the impact that rigid, absolutistic self-appraisals have on mtrelated confidence. however, these findings cannot be generalised beyond adolescent female athletes. nor should these findings be considered generalizable to more individual sporting contexts. further research is needed to determine whether negative self-appraisal mediates the relationship between dm and confidence in other athlete populations and in contexts other than team sports. in addition, the current study investigated the relationship between dm, negative selfappraisal and mt-related confidence. single case series and controlled intervention studies would go a long way towards demonstrating whether mindfulness-based interventions lead to improved confidence by reducing the intensity, frequency and believability of rigid and global negative self-appraisal. the findings of the current study should only be interpreted within the constraints of the specific model that was tested. consequently, no inferences can be drawn regarding the possible mediating role of constructs other than negative selfappraisal. similarly, the utility of constructs other than dm to influence confidence via negative self-appraisal have not been determined. studies that explore the conditional interactions between multiple psychological processes and changes in confidence are required. the impact of dm on metacognitive processes, such as intolerance of uncertainty and rumination, as well as their subsequent impact on confidence, would be a fruitful avenue of future research. finally, while data were collected via developmentally appropriate measures of dm and self-appraisal, the confidence component of mt was measured with an instrument intended for use with adult populations. although little research has been conducted in this area, it is plausible that developmentally-related differences in mt exist between adolescents and adults. consequently, these findings cannot be considered to be the final word on the interaction between dm, self-appraisal and mt in adolescents. conclusion the current study furthers the understanding of mechanisms through which dm impacts upon athletic performance. dm has been demonstrated to result in lower levels of negative selfappraisal which, in turn, result in an increase in adolescent female athletes' confidence to meet the challenges of competitive sport. the promotion of mindfulness thus appears to provide an avenue through which to lessen the impact of patterns of rigid thinking on the confidence of adolescent female athletes. references 1. bishop sr, lau m, shapiro s, et al. mindfulness: a proposed operational definition. clin psychol sci pract 2004;11(3):230-241. [doi: 10.1093/clipsy.bph077] 2. rau hk, williams pg. dispositional mindfulness: a critical review of construct validation research. pers individ dif 2016;93(1):32-43. [doi: 10.1016/j.paid.2015.09.035] 3. sappington r, longshore k. systematically reviewing the efficacy of mindfulness-based interventions for enhanced athletic performance. j clin sport psychol 2015;9(3):232-262. [doi: 10.1123/jcsp.2014-0017] 4. walker sp. mindfulness and burnout among competitive adolescent tennis players. s afr j sports med 2013;25(4):105-108. [doi: 10.7196/sajsm.498] 5. birrer d, röthlin p, morgan g. mindfulness to enhance athletic original research 5 sajsm vol. 31 no. 1 2019 performance: theoretical considerations and possible impact mechanisms. mindfulness 2012;3(3):235. [doi: 10.1007/s12671012-0109-2] 6. josefsson t ivarsson a, lindwall m, et al. mindfulness mechanisms in sport: mediating effects of rumination and emotion regulation on sport-specific coping. mindfulness 2017;8(5):1354-1363. [doi: 10.1007/s12671-017-0711-4] 7. walker sp. mindfulness and mental toughness among provincial adolescent female hockey players. s afr j sports med 2016;28(2):46-50. [doi:10.17159/2078-516x/2016/v28i2a1110] 8. sheard m, golby j, van wersch a. progress toward construct validation of the sport mental toughness questionnaire (smtq). euro j psychol assess 2009;25(3):186-193. [doi:10.1027/1015-5759.25.3.186]. 9. clough pj, earle k, sewell d. mental toughness: the concept and its measurement. in: cockerill i, ed. solutions in sport psychology. london: thomson, 2002:32-45. 10. vealey rs, chase ma. self-confidence in sport: conceptual and research advances. 3rd ed. in: horn ts, ed. advances in sport psychology. champaign, il: human kinetics, 2008:65-97. 11. mcgrane b, belton s, powell d, et al. the relationship between fundamental movement skill proficiency and physical selfconfidence among adolescents. j sports sci 2017;35(17):17091714. [doi: 10.1080/02640414.2016.1235280] 12. lazarus rs, folkman s. stress, appraisal, and coping. new york: springer pub. co., 1984. 13. digiuseppe ra, doyle ka, dryden w, et al. a practitioner’s guide to rational emotive behavior therapy. 3rd ed. new york: oxford university press, 2013. 14. turner mj, barker jb. using rational emotive behavior therapy with athletes. sport psychol 2014;28(1):75-90. [doi:10.1123/tsp.2013-0012] 15. arthur-cameselle j, sossin k, quatromoni p. a qualitative analysis of factors related to eating disorder onset in female collegiate athletes and non-athletes. eat disord 2017;25(3):199215 [doi:10.1080/10640266.2016.1258940] 16. greco la, baer ra, smith gt. assessing mindfulness in children and adolescents: development and validation of the child and adolescent mindfulness measure (camm). psychol assess 2011;23(3):606-614. [doi:10.1037/a0022819]. 17. bernard me, cronan f. the child and adolescent scale of irrationality: validation data and mental health correlates. j cognit psychother1999;13(2):121-132. [doi: 10.1891/08898391.13.2.121] 18. hayes af. introduction to mediation, moderation, and conditional process analysis: a regression-based approach. new york: guilford press, 2013. 19. foster j, parker i. carrying out investigations in psychology: methods and statistics. leicester: wiley-blackwell, 1995. 46 sajsm vol. 27 no. 2 2015 original research background. injuries occurring at the popular schoolboy rugby festivals in south africa have not previously been evaluated. a rugby festival is a unique event with multiple matches occurring over a 5-day period and a potentially increased risk of injury compared with adult games. objectives. to analyse the prevalence and type of injuries over 2 years of a johannesburg high school rugby festival, to compare the injuries between the 2 years and to compare the injuries between the 3 days of the festivals. methods. the study design was a retrospective, descriptive and observational study. the study population were participating rugby players at the two rugby festivals in 2010 and 2011 who came to the medical tent provided. a standardised medical form was used to capture data. results. a total of 626 players participated with 100 injury data sets analysed over the 2 years. the injury rate per player was 17% in year 1 and 15% in year 2. there was no statistical difference (p=0.65) in the injury numbers between the 2 years. the injury profiles between the respective days and between the 2 years were not statistically different. most injuries were to the head/face (30%), with the majority being concussion related (6%). tackles were the most common mechanism of injury. overall 24% of injuries were deemed severe enough to stop the players from continuing play. few injuries required referral for investigations or specialist physician care (19% and 2%, respectively) and most were managed with simple first aid at the primary care level. conclusion. the number, nature and mechanisms of rugby injuries at this rugby festival were similar to numerous local and international studies of schoolboy rugby players. adequate standardised record keeping is recommended to increase knowledge and monitor trends. s afr j sports med 2015;27(2):46-49. doi:10.7196/sajsm.596 injuries at johannesburg high school rugby festivals d constantinou,1 mb bch, bsc (med)(hons), msc (med), ffims; a bentley,2 mb bch, phd 1 centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 department of family medicine, school of clinical medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: d constantinou (demitri.constantinou@wits.ac.za) there are numerous school-level, friendly rugby competitions in south africa (sa), of which the easter rugby festivals are possibly the most popular. these are held for 3 days over the easter weekend at a number of schools around the country, and in gauteng three schools host easter rugby festivals. concerns have been raised, across the world, regarding the safety of the sport due to its physical, high-impact nature and an increasing number of injuries.[1,2] injuries in rugby, at school and senior club level have been reported in great britain, australasia and sa.[3-7] averages of between 6.8 and 129.8 injuries per 1 000 player hours of matches occur in schoolboys.[4,7,8] most studies look at injuries over full seasons or a number of years and present data in differing ways such as per 10 000 hours played[9] or 1 000 hours played.[10] injury surveillance is important in injury prevention strategies.[7,11] it is difficult to know how this translates to one event over 3 days of play and thus makes it difficult to plan medical services. most injuries reported to occur in rugby players are to soft tissue, occurring mainly to ligaments and tendons, are due mainly to collisions and occur particularly in the head, neck and lower limbs.[4,5] injuries are also more likely to occur at competitions compared with training periods.[3,4,7] there are possible precipitating causes unique to schoolboys in that the boys may often be mismatched in size[12] and experience due to the difference in pubertal growth spurts. sa data on schoolboy rugby injuries exist[12,13] but given the significant and ongoing changes in the rules of the game, the improved facilities for schoolboy rugby, and the recognised need for injury surveillance, an investigation into rugby injuries using the schoolboy rugby festivals as a convenient event was warranted. the objective of the research was to analyse the prevalence and type of injuries over 2 years of a johannesburg high school rugby festival, and to specifically describe injuries (number, anatomical sites, types and severity), to compare injuries between the 2 years and compare injuries between the 3 days of the festivals. methods setting the rugby festivals were held over 3 non-consecutive days: on the thursday before the christian religious holiday of easter friday, on the following saturday and then on the monday thereafter. at these festivals over 300 boys participated from 22 schools. thirty-five matches were played for an average 35 minutes each, and each player could play between one and three matches. the refereeing was done by certified provincial referees. fully-equipped medical facilities were available during the festivals, and with at least one medical doctor, paramedics, first aiders, a nurse and physiotherapists on duty. a local hospital with an advanced trauma unit, and fast-tracked radiograph facilities were available for referral. study design the study design was a retrospective, descriptive observational study. the study population were the participating rugby players at the rugby festivals in 2010 and 2011. inclusion criteria were all completed medical records that had adequate information of rugby-related injuries in schoolboy rugby participants at the festival. the injury recording form of the injury international consensus[14] was used for sajsm vol. 27 no. 2 2015 47 capturing injury data. injury severity was assessed by whether the injury was severe enough for the player to stop or be withdrawn from playing in the match where they sustained the injury; the decision was made by the medical personnel and verified by the researcher. data were collected on: injury type and severity, anatomical site, mechanism of injury, referral to hospital or for investigations, withdrawal from play at time of injury and management. information was obtained from the injured player and where possible verified by first aiders/paramedics, coach, parent/s and/or peers. ethical considerations permission for use of the medical records for research was granted by the host school. ethics permission was granted by the university’s human research ethics committee (medical) for human subjects (number m120229). participating schools and players signed indemnities and allowed for injury recording during the rugby festivals. no identifying data were used in the analysis. data analysis as there were 100 data points the number is equal to the percentage and these are used interchangeably in the results section. percentages were used to describe categorical data and medians and confidence intervals (cis) for numerical data. comparative statistics for the 2 years was done using fisher’s exact test and between the different days of the festival using non-repeated measures analysis of variance (anova) tests. the data were analysed using graphpad prism for windows (graphpad software, usa) and statistica v12 (statsoft inc, usa). a level of significance of p<0.05 was used. results in both years of the festival, 12 high schools and 10 preparatory schools participated with a total of 69 matches played (36 and 33 in 2010 and 2011, respectively). a total of 626 players participated (322 and 304 in each year, respectively) in the rugby festivals with a total of 111 injuries recorded over the 2 years. incomplete data sets were not included (5 and 6 in each year, respectively) leaving a total of 100 data sets for analysis. the injury rate was 408 injuries per 10 000 match hours and the injury rate per player in year 1 (17%, 95% ci 33 84%) was not significantly different to that in year 2 (15%, χ2=0.203, p=0.65, 95% ci 30 80%). over the 35 matches there was an injury rate of 1.5 injuries per match in year 1 and 1.4 injuries per match in year 2. the overall injuries divided by day of festival, year of festival and anatomical area are listed in table 1. most injuries occurred to the head and neck, followed by the lower limb and upper limb. there was no significant difference between anatomical sites of injury between the 2 years of the rugby festivals (p=0.64, fisher’s exact test) nor was there any difference between respective days of the 2 years (day 1 p=0.63, day 2 p=0.07, day 3 p=0.32 fisher’s exact). there was also no significant difference in the anatomical site of injury between the 3 days of the festival (p=0.06, χ2 test). of the lateralised injuries 37% and 20% occurred on the right side and 30% and 26% on the left side (years 1 and 2 respectively), and this difference was not significantly different. the balance were not lateralised (e.g. abdomen). the majority of the rugby players (85% in year 1 and 78% in year 2) had not previously had similar injuries. the types of injury sustained by year of festival are indicated in fig. 1. the majority of the injuries were to soft tissue in both years (72% in year 1 and 77% in year 2). there was a significant difference in the frequency of injury type between the years (p=0.02) mainly because there were incidences of dislocations, lacerations and fractures in year 1, but not in year 2. there were no fractures of the cervical spine. almost half of the injuries were due to tackles with the next most common injury resulting from accidental collision (fig. 2). in year 1, 27% of all the injured players were stopped from continuing (indicating severity) compared with 22% in year 2. this difference was not statistically significant (p=0.64, χ2). no catastrophic injuries such as severe neck injuries with neurological fallout were sustained. most injured players were given advice on their injuries, which were relatively minor. the most common form of management was basic first aid following the rice (rest, ice, compression and elevation) principle, which was then followed by referral for soft tissue table 1. injuries by day of festival, year of festival and anatomical area head/neck (n=42) torso (n=7) upper limb (n=22) lower limb (n=29) h ea d/ fa ce n ec k st er nu m / ri bs lo w er b ac k sh ou ld er u pp er a rm e lb ow fo re ar m w ri st h an d th ig h k ne e lo w er le g a nk le fo ot /t oe to ta l ( by da y) to ta l year 1 n=54 day 1 6     1           1   1   1   10 day 2 2 3 3 1 2   1     4 2 1 2 2 1 24 day 3 4 1     2         3 1 6   1 2 20 year 2 n=46 day 1 8 2       1 1 2       2       16 day 2 5 4 1         2 1   1 1       15 day 3 5 2 1     1 1       1 4       15 total 30 12 5 2 4 2 3 4 1 8 5 15 2 4 3   100 48 sajsm vol. 27 no. 2 2015 therapy using physiotherapy and medications that were non-steroidal anti-inflammatories or analgesics. treatment may not have been mutually exclusive, for example, there may have been both rice and physiotherapy. there was no significant difference between the two years in management of injuries (p=0.58). there was a significant difference in referrals for radiographs between the 2 years (p=0.01, χ2). nine players were referred for radiographs in year 1 and 19 in year 2 with only one schoolboy referred for a magnetic resonance imaging scan in year 1. one-third of these referrals were for suspected neck injuries and the remainder for suspected fractures, avulsion injuries and dislocations of peripheral joints. two of the players had fractures confirmed and were then immobilised and referred to orthopaedic surgeons for further management. discussion overall for the 2 years and 6 days of the easter rugby festivals, there were 100 injuries most of which were to the head and neck, to soft tissue and usually did not prevent the player returning to the game. as expected most injuries resulted from tackles and accidental collisions. there were no differences in anatomical area or type of injury between days of the festival or years of festival. there were limitations to this study, particularly owing to the method of reporting injuries. the data collection forms used a standardised international form[14] that had flaws; there was no place for side dominance of the players, nor their age. details of how many matches and how much time each individual player had played would also add value. thus individual risk determination where exposure in participation is important could not be assessed. some injured players may have not presented to the available medical centre at the festivals for assessment or management. there may also be faults in the mechanism of injury where they do not want to report the truth as very few reported foul play, which may not be a true reflection. another limitation is that the results cannot be extended to all schoolboy rugby festivals and schoolboy rugby competitions, or even playing in normal matches taking place weekly with adequate time to recover between matches. these festivals were hosted by a school that had resources with respect to funding, access to expert medical care with good facilities, and access to qualified referees. over the 2 years in this study a total of 100 injuries were recorded over the two rugby festivals, played over 6 days. thus an average year 1 year 2 16 14 12 10 8 6 4 2 0 n u m b er co nt us io n lig am en t s pr ain co nc us sio n m us cle in ju ry ab ra sio n ot he r b on e i nj di s/s ub lu xa tio n la ce ra tio n fr ac tu re ot he r fig. 1. injury types and frequencies in years 1 and 2. (inj = injuries; dis = dislocation.) year 1 year 2 70 60 50 40 30 20 10 0 pe rc en ta g e tackling accidental collision foul play (other player) other* direction change running hit by ball fig. 2. mechanisms of injury over the two years of the rugby festival. (*for example non-contact (falling).) ri ce ad vic e ph ys io th er ap y m ed ica te d su tu re d cl ea ne d an d dr es se d 40 35 30 25 20 15 10 5 0 pe rc en ta g e year 1 year 2 fig. 3. management of injuries after assessment (rice). sajsm vol. 27 no. 2 2015 49 of just over 16 injuries per day was evident. the injury frequency found in this study is not unlike the results found elsewhere.[1,8] an average of 1.5 injuries per match in this study is lower than some other studies[4,6,8] although the differing methods of reporting make comparisons difficult. there was no way of logistically recording time exposure of each of the injured players individually, thus injuries could not be reported as per hour units of exposure. the festival is unique for a number of reasons, which make these data difficult to compare to others. players play three matches over 3  days on the easter weekend. one could theorise that perhaps injuries would have been higher on the first day, with increased vigour and excitement of the participating players; alternatively the third day could be a more vulnerable time due to player fatigue. however, the results show that there was no significant difference in the frequency of injuries on any of the 3 festival days. the fact that there were also no differences between days across the 2 years supports this. the majority of injuries were of the head and face followed by the lower limbs, which is different to some previous data indicating the lower limbs to be the most likely followed by the head and neck.[3,4,5] however, there is another study with similar data.[6] in children the head size is relatively large compared to the total body, and there is an increased head-neck girth that may explain more head and headrelated injuries in younger players. our data are similar to those found in adult rugby players, possibly due to the participants being in the latter years of schooling and their ages closer to reported adult players. further, changes in refereeing and or coaching may influence the site of injury, but cannot be determined. law changes related to tackles and to scrums at the time may also have played a role. in chronic and/or overuse injuries, having had a similar previous injury is a known risk for another similar injury occurring and is a trend also found in young players.[15] however this was not the case in the setting of acute traumatic injuries typically sustained in the rugby festivals, where it was shown that there was no significant history of a previous similar injury having occurred. other expected results that conform to the literature are that tackles are the most common mechanism of injury at 48 60% of all injuries compared with 55% of injuries over one rugby season occurred in tackles as reported previously.[4] injury severity was difficult to compare to previous literature as there was no follow up in the cases in this study compared with more controlled environments. fortunately there were no catastrophic neck injuries in the study cohort. most management of injuries at the rugby festivals required basic first aid (rice), to reduce swelling and pain. this was followed by referral for soft tissue therapy using physiotherapy and medication. this was appropriate for soft tissue injuries of ligaments, muscles and contusions as seen in similar studies.[16,17] along with the minor nature of most injuries there were very few referrals for radiographs. there were more referrals in year 2 despite there being less fractures and dislocations in that year. the difference cannot thus be explained by the type of injury nor the clinical criteria for referral, which would have been similar in both years. one can only conclude that the level of injuries was different, such that where there were ligament injuries they did not appear to have bony pathology associated with them, or were not of a nature or severe enough to cause joint instability. why that should be different over the two festivals is unclear. parent or coach pressure for the young players to return to play is a factor in this rugby festival environment that may have influenced the decision to conduct an investigation. thus medical personnel may refer for investigations to exclude radiologically evident pathology. conclusion rugby is a collision sport and as such injuries do occur and can range in severity from minor to catastrophic. the easter rugby festival, a schoolboy event studied in this paper, recorded an injury rate of 1.6 per match, most of which were to soft tissue and could be handled on the side of the field. this may be due to good facilities and referees at the festival. other schoolboy rugby events without the same good resources may have differing results and more research is required to document whether the facilities and referees do indeed have a significant role to play in preventing severe injury in rugby matches. references 1. nicol a, pollock a, kirkwood g, parekh n, robson j. rugby union injuries in scottish schools. j pub health 2011;33(2):256-261. [http://dx.doi.org/10.1093/pubmed/fdq047] 2. quarrie kl, cantu rc, chalmers dj. rugby union injuries to the cervical spine and spinal cord. sports med 2002;32(10):633-653. [http://dx.doi.org/10.2165/00007256200232100-00003] 3. lee aj, garraway wm. epidemiological comparison of injuries in school and senior club rugby. br j sports med 1996;30(3):213-217. [http://dx.doi.org/10.1136/ bjsm.30.3.213] 4. roux ce, goedeke r, visser gr, van zyl wa, noakes td. the epidemiology of schoolboy rugby injuries. s afr med j 1987;71(5):307-313. 5. nathan m, goedeke r, noakes td. the incidence and nature of rugby injuries experienced at one school during the 1982 rugby season. s afr med j 1983;64(4):132-137. 6. davidson rm. schoolboy rugby injuries, 1969-1986. med j aust 1987;147(3):119-120. 7. freitag a, kirkwood g, scharer s, ofori-asenso r, pollock am. systematic review of rugby injuries in children and adolescents under 21 years. br j sports med 2015;49(8):511-519. [http://dx.doi.org/10.1136/bjsports-2014-093684] 8. parekh n, hodges sd, pollock am, kirkwood g. communicating the risk of injury in schoolboy rugby: using poisson probability as an alternative presentation of the epidemiology. br j sports med 2011;46(8):611-613. [http://dx.doi.org/10.1136/ bjsports-2011-090431] 9. davidson r, kennedy mj, vanderfield g. casualty room presentations and schoolboy rugby union. med j aust 1978;1(5):247-249. 10. macintosh as. rugby injuries. in: cd maffulli n, ed. epidemiology of pediatric sports injuries: team sports. basel: karcher; 2005:120-139. 11. burger n, lambert mi, viljoen w, brown jc, readhead c, hendricks s. tacklerelated injury rates and nature of injuries in south african youth week tournament rugby union players (under-13 to under-18): an observational cohort study. br med j open 2014;4(8):e005556. [http://dx.doi.org/10.1136/bmjopen-2014-005556] 12. krause lm, naughton ga, denny g, patton d, hartwig t, gabbett tj. understanding mismatches in body size, speed and power among adolescent rugby union players. j sci med sport 2014;18(3):358-363. [http://dx.doi.org/10.1016/j.jsams.2014.05.012] 13. brown j, verhagen e, viljoen w, et al. the incidence and severity of injuries at the 2011 south african rugby union (saru) youth week tournaments. s afr j sports med 2012;24(2):49-54. 14. fuller cw, brooks jh, cancea rj, hall j, kemp sp. contact events in rugby union and their propensity to cause injury. br j sports med 2007;41(12):862-867. [http://dx.doi. org/10.1136/bjsm.2007.037499] 15. hagglund m, walden m, ekstrand j. previous injury as a risk factor for injury in elite football: a prospective study over two consecutive seasons. br j sports med 2006;40(9):767-772. [http://dx.doi.org/10.1136/bjsm.2006.026609] 16. bleakley cm, o’connor s, tully ma, rocke lg, macauley dc, mcdonough sm. the price study (protection rest ice compression elevation): design of a randomised controlled trial comparing standard versus cryokinetic ice applications in the management of acute ankle sprain. bmc musculoskelet disord 2007;19(8):125. [http://dx.doi.org/10.1186/1471-2474-8-125] 17. laskowski er, najarian mm, smith am, stuart mj, friend jf. medical coverage for multievent sports competition: a comprehensive analysis of injuries in the 1994 star of the north summer games. mayo clin proc 1995;70(6):549-555. [http://dx.doi. org/10.4065/70.6.549] km_c227-20180711130430 original research 1 sajsm vol. 30 no. 1 2018 the association between being overweight/obese and blood pressure in rural south african women living in the tshino nesengani (mukondeleli) village p j-l gradidge, phd1; m phaswana, bsc (hons)1; e cohen, phd2 1 centre for exercise science and sports medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 mrc/wits developmental pathways for health research unit, department of paediatrics, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: p j-l gradidge (philippe.gradidge@wits.ac.za) the prevalence of both abdominal and whole body obesity is expected to increase dramatically in developing countries, such as south africa, with recent data demonstrating that black south african women have the highest prevalence of obesity within sub-saharan africa.[1] south african women living in urban settings certainly have higher rates of obesity compared with men and rural women;[2] however, the prevalence of excess adiposity in women living in both settings is higher than the global averages.[1] a consequence is that the risk of associated cardiometabolic diseases, such as type 2 diabetes and hypertension, is high in african women.[3] the obesity crisis in south africa is made more complex by the dynamic rural-urban shift, which may include an extension of the urbanisation concept into the rural setting as observed in other countries experiencing nutritional transition.[4] this phenomenon may explain the high prevalence of excess adiposity in both settings as learned obesogenic practices such as sedentariness and unhealthy eating may be adopted by rural communities. research indicates that the global consumption of sugarsweetened beverages (ssb) has increased and is associated with weight gain, elevated blood pressure (bp) and other cardiometabolic diseases risk factors.[5] despite black south african females having the highest prevalence of obesity in the sub-saharan region, the results of the south african demographic and health survey show that other population groups have higher tobacco and alcohol consumption patterns.[6] this suggests that there may be other environmental factors driving the high prevalence of obesity and cardiometabolic diseases in african women. these other environmental factors have received far less attention than diet or physical activity. they include smoking and sleep behaviour. smoking is well known as an independent risk factor for several cardiovascular diseases, while sleep duration has a negative association with bmi,[7] although the mechanisms underlying this effect are largely unknown. the aim of this study was therefore to determine whether other environmental factors (e.g. physical activity, sedentary behaviour, consumption of ssbs, smoking, smokeless tobacco consumption or ‘snuff’, and sleep duration) correlate independently or with the measurements of fat and bp in a cohort of rural african women. methods sample this was a cross-sectional study of a convenience sample of rural black south african women living in the tshino nesengani (mukondeleli) village, limpopo province, south africa. potential participants who were pregnant, aged <18 years, non-black, and living outside of the village were excluded from the study. ethical approval was granted by the human research ethics committee (medical), university of the witwatersrand (ethics certificate number: m170377), and all participants gave written consent. the questionnaires were administered to the participants and the details communicated in the participants’ home language when necessary to ensure correct completion of the questionnaires. physical activity the global physical activity questionnaire (gpaq) was used to determine self-reported total moderate-vigorous physical activity (mvpa) and the estimated sitting time. the gpaq is reliable and has been validated for use in africa.[8] active in the gpaq was defined as taking part in: moderate physical activity for a total of 150 minutes per week (≥five days per week); or vigorous physical activity for 60 minutes per week (≥three days per week); or 600 metabolic minutes per week (≥five days mvpa).[8] in addition, walking for travel purposes, as a domain of light physical activity, was determined using the gpaq. background: the purpose of this cross-sectional study was to investigate whether bio-behavioural factors are associated with blood pressure and body composition in rural black south african women. methods: data were collected on 200 african women living in the tshino nesengani (mukondeleli) village, limpopo province, using simple anthropometry, blood pressure, and self-reported questionnaires for sleep, physical activity, and sugar-sweetened beverage (ssb) consumption. results: six patterns of ssb consumption were determined by principal component analysis. regression analysis showed that longer sleep duration patterns (≥nine hours/night) was associated with lower systolic and diastolic blood pressure; whilst the principal components (beer, wine, and sweetened tea) were associated with a higher body mass index. conclusion: these findings highlight novel bio-behavioural contributors of blood pressure and body anthropometry in rural african women. keywords: african, bmi, waist circumference, sugarsweetened beverages s afr j sports med 2018; 30:1-5. doi: 10.17159/2078-516x/2018/v30i1a5066 http://dx.doi.org/10.17159/2078-516x/2018/v30i1a5066 original research sajsm vol. 30 no. 1 2018 2 beverage intake the beverage intake questionnaire (bevq-15) is a 15-item, seven day recall on ssb used to measure the quantities and amounts of habitual beverage consumption.[9] the bevq-15 includes 15 categorised beverage items to estimate total kilocalories (kcal) of consumed beverages: water, regular soft drinks, 100% fruit juice, juice drinks (other than fruit juice), full cream milk, low-fat milk, skim (fat-free) milk, sweetened tea, coffee or tea with milk and sugar, black coffee or tea without sugar, light beer, regular beer, mixed alcoholic drinks, wine (red or white), meal replacement drinks and energy drinks. the total of ssb calorie consumption is calculated from the estimated energy consumption for each item. participants were asked to recall the amount and frequency of each item. sleep patterns the pittsburgh sleep questionnaire index (psqi) was used to determine the overall quality of sleep.[10] the psqi is a selfreported questionnaire consisting of seven components of sleep that evaluate sleeping duration, sleep disturbance, sleep latency, habitual sleep efficiency, daytime dysfunction, use of sleeping medicine, and sleeping quality. the total score ranging from 0-21 is summed from these items. a total score >five indicates poor sleep quality for the global psqi index, and a score of ≤five indicates good sleep quality. socioeconomic status and education household asset ownership was used as a proxy measure of socioeconomic status (ses).[11] the questionnaire included eleven household items, ranked in order of value from lowest to highest: (1) radio, (2) computer/laptop, (3) refrigerator, (4) washing machine, (5) television (tv), (6) telephone/landline, (7) cell phone/mobile, (8) internet, (9), electricity, (10) digital satellite tv, and motor vehicle. the score of these commodities was summed to give a total ses index ranging from 0 to 66. tertiles of ses score were created for further analysis: low (ses score: <29), moderate (ses score: 29-36), and high ses (ses score ≥36) categories. the levels of education were captured as follows: 0 for no schooling, 1 for primary school, 2 for incomplete high school, and 3 for completion of high school. participants were also queried on their employment status. anthropometry all measurements were performed with participants in light clothing and without shoes. body weight was measured using an electronic digital weighing scale to the nearest 0.1 kg (seca, usa). height was measured to the nearest 0.1 cm using a stadiometer (seca, usa). body mass index (bmi) was calculated as weight (kg)/height (m2). waist and hip circumferences were measured using a spring tape to the nearest cm. waist circumference was measured between the lowest ribs and the iliac crest, and hip circumference was measured at the greatest protuberance just below the gluteal line. blood pressure resting bp was measured using a digital bp monitor (omron m6 version hem-7001-e, omron, kyoto, japan). participants were seated for a minimum of five minutes before the first bp measurement was done. two subsequent measurements were taken with rest periods in between. the average of these latter two readings was used to determine mean resting bp. statistical analysis descriptive statistics were presented as mean ± standard deviation, median (interquartile range), or percent in tables. a principal component analysis (pca) was performed with all bevq-15 items except water and diet soft drinks (due to zero and low caloric values) to determine patterns of ssb consumption. the following steps were followed: (1) the covariance matrix was applied, (2) the variance loadings were rotated using the varimax with the kaiser normalisation orthogonal method. these authors could perform a pca on the covariance matrix of ssb variables because the bartlett’s test of sphericity was good (p<0.0001) and kaiser-meyer-olkin measure was acceptable (0.524). six principal components (pc) on ssb matrix consumption were initially retained based on eigenvalues ≥1 and the scree plot observation. pc1 (hot tea/coffee with added sugar and energy drinks) explained 15.8% of the variance, while pc2 (beer and iced tea) and pc3 (low-fat milk and spirits) explained 12.1% and 10.9% of the variance respectively. the associated eigenvalues were 2.05, 1.58 and 1.41, respectively. the first four components also had the greatest factor loading with correlations ≥0.30 in the same direction, resulting in pc5 and pc6 being removed from an additional analysis. bivariate models were created to determine the association of plausible lifestyle behaviours variables with bmi and waist circumference. those variables with p<0.20 were included in the initial backward stepwise multivariable linear regressions models. thus the independent variables for the bmi model included age, employment status, hypertension, short sleep (<six hours/night), long duration sleep (≥nine hours/night), ses, and pc2. the waist circumference model included age, employment status, highest level of education, ses, pc2, and bmi. the systolic and diastolic models included age, bmi, employment status, ses, and long sleep (≥nine hours/day). the reference groups for the categorical variables were nonhypertensive, night-time sleep duration seven-eight hours per night, unemployed, and incomplete high school and primary school. multicollinearity in these regression models was checked using variance inflation factor and is reported in the regression table. only the β values with p≤0.05 were displayed in the regression results table. all statistical analysis was conducted using stata ver. 14.2 (statacorp, texas, usa). results participant characteristics a total of 200 adult women volunteered to participate in this study. table 1 displays that women in the highest tertile of bmi (bmi-t3) were approximately 13 years older than women in the lowest tertile of bmi (bmi-t1) and had a 2.5-fold higher prevalence of employed women and a mean ses score that was significantly higher (p<0.0001). the mean bmi and waist original research 3 sajsm vol. 30 no. 1 2018 circumference of the study’s population were 28.5 ± 7.3 kg.m2 and 87.7 ± 16.8 cm respectively, and the presence of overall obesity (40%) and central obesity (67%) were high. the systolic and diastolic bp values of the bmi-t3 group were significantly higher than the bmi-t1 group (p<0.0001), and the presence of hypertension in the sample was 26%. the physical activity profile of the women in bmi-t1 was similar to those in bmi-t3; however, women in the former group walked significantly more (p<0.05). sleep duration was approximately one hour lower in women in bmi-t3, while the proportion of women in bmi-t1 with short duration sleep (<six hours/ night) was 7% lower than women in bmi-t3. the overall presence of smoking and snuff consumption was low in the study population, while ssb consumption was similar between bmi groups. correlates of bmi and waist circumference (wc) table 2 shows that being physically active did not have an association with bmi or wc, while consuming a high frequency of alcohol (≥four days/week) was associated with higher bmi, but not wc. completion of high school was associated with a significantly lower wc, but not bmi. subjects who were employed had higher bmi and wc values compared with those who were unemployed. high ses was positively associated with bmi, and not wc, while neither smoking status nor consumption of snuff was associated with bmi or wc. those subjects with short sleep duration (< six hours/night) showed a trend for higher bmi, while this association was not observed for wc. longer duration sleep (≥nine hours/night) displayed no effect on bmi and wc. further, pc2 was positively correlated with bmi (r=0.1, p=0.048) and had a trend for a positive correlation with wc (r=0.1, p=0.08). the other derived principal components were not correlated with anthropometry. the results of the multivariable linear regression analysis for the detection of anthropometry correlates are displayed in table 3. age, pc2, hypertensive status, and high ses were significantly correlated with bmi, accounting for 17.5% of the variance. bmi and completion of high school were positively and negatively respectively correlated with wc, accounting for 59% of the variance. correlates of blood pressure (bp) in univariate analysis, hours of night-time sleep was positively associated with systolic and diastolic bp in the highest quartiles for age (age: ≥ 47 years old), β: -0.4, p=0.01 and β: -0.5, p<0.0001, respectively. systolic bp is 9% lower in women who sleep for longer durations per night than those who slept for normal durations (seven-eight hours/night). in contrast those who sleep for longer durations have a 5.6% lower diastolic bp compared to those with normal sleep time. the findings of the multivariable linear regression models indicate that women with longer sleep have better systolic and diastolic bp, while age and bmi increase linearly with bp (table 3). discussion the prevalence of obesity in this cohort of rural-dwelling african women was high, and as previously shown in other studies of black south african women, most of the study’s population were sufficiently physically active according to the gpaq-measurement of self-reported physical activity.[11, 12] the findings show a relationship between pattern of ssb consumption and bmi, and in view of the recent implementation of the ‘sugar tax’, further investigation is table 1. participant characteristics according to lowest and highest tertiles for bmi demographic variable total sample (n=200) bmi t1 (n=67) bmi t3 (n=67) age (years) 38 ± 16 28 ± 12 41 ± 15*** employed (%) 28 15 37 no schooling (%) 2 2 2 primary school (%) 7 5 5 incomplete high school (%) 41 42 42 completed high school (%) 50 52 52 household ses index 34 ± 10 32 ± 9 38 ±10*** anthropometry bmi (kg/m2) 28.5 ± 7.3 21.0 ± 2.3 36.6 ± 5.2*** wc (cm) 87.7 ± 16.8 74.1 ± 8.1 102 ± 14.6*** hc (cm) 107.0 ± 14.5 95.5 ± 7.3 120.0 ± 12.1*** central obesity (%) 67 27 97*** blood pressure sbp (mm hg) 123 ± 1 115 ± 2 129 ± 2*** dbp (mm hg) 80 ± 1 74 ± 1 84 ± 2*** hypertension (%) 26 9 39*** physical activity measures sitting time (hours/day) 4 (3, 5) 4 (2, 5) 4 (3, 5) no physical activity (%) 6 6 3 mvpa (mins/week) 247 (120, 428) 210 (120, 390) 260 (135, 414) gpaq active (%) 72.5 73.1 73.1 walking for travel (mins/week) 150 (60, 260) 180 (90, 270) 120 (50, 240) sleep behaviour sleep hours/night 9 ± 2 9 ± 2 8 ± 2* 7-8 hours/night (%) 38 36 37 <6 hours/night (%) 9 6 13 ≥9 hours/night (%) 54 58 49 global psqi index 4.7 ± 2.5 4.4 ± 2.5 4.4 ± 2.1 tobacco consumption current smoker (%) 3 3 3 consumes snuff (%) 6 2 6 total ssb (kcal) 295 (137, 598) 313 (146, 556) 288 (81.7, 798) data presented as mean ± sd or median (interquartile range) or percentage (%). *p<0.05, **p<0.005, ***p<0.005 versus tertile 1 (t1) body mass index (bmi). hc, hip circumference; wc, waist circumference; kcal, kilocalories; psqi, pittsburgh sleep questionnaire index; mvpa, moderate vigorous physical activity; ses, socioeconomic status; gpaq, global physical activity questionnaire; ssb, sugar-sweetened beverage. original research sajsm vol. 30 no. 1 2018 4 needed to determine the impact of this regulation on longterm changes in public health. the prevalence of hypertension was significantly higher in those with elevated bmi, with longer sleep duration associated with better bp profile in the study cohort. longer night-time sleep was associated with lower systolic and diastolic bp in this study, which is contrary to an earlier study of urban african women showing an inverse relationship.[7] the findings of this study support preliminary findings of other studies suggesting protection against hypertension with extended sleep duration.[13] however, some studies have shown a u-shaped relationship between sleep duration and bp, indicating higher levels of bp with shorter and longer duration sleep, even if these results are not supported by international obesity guidelines recommendations.[14] the mechanistic pathways involved in the relationship between the duration of sleep and changes in bp are complex. for example, changes in sleep patterns can influence increases in metabolic biomarkers resulting in the higher risk of cardiovascular disease, suggesting that other contributors may be involved.[15] this study did not find a relationship between measures of fat and sleep duration, supporting the findings of peltzer and pengpid,[15] while pretorius et al.[7] observed an inverse association only in those female subjects older than 40 years, suggesting a possible mediating effect of age in the relationship between longer sleep and lower bmi in african women. the sleep patterns of african women also tend to differ in rural and urban settings respectively,[7,15] with these literature showing that sleep quality is better in the urban setting, possibly due to better access to amenities such as electricity and being employed in less energy demanding work. finally, with pc2, a significant positive association was noted with bmi, while no significant associations were noted for the other principal components. the observed positive relationship between pc2 “beer and sweetened tea” and bmi is consistent with global trends in ssb consumption.[5] the consumption of ssbs has deleterious implications on cardiovascular health,[5] indicating the urgent need for intervention in populations most susceptible to weight gain as a consequence of habitual consumption. the limitations of this study included the use of self-reported instruments and the cross-sectional study design; however, the findings of this study are important in understanding the factors associated with anthropometry in rural-dwelling african women. conclusion this study also confirms the high prevalence of obesity and the associated elevated bp in african women living in a rural south african village. the influence of extended sleep on lowering bp table 2. anthropometric values in various stratified population groups category bmi β (95% ci) wc β (95% ci) physically active no 27.7 ± 6.2 84.9 ± 20.0 yes 28.8 ± 7.7 1.0 (-1.3, 3.3) 88.7 ± 15.3 3.9 (-1.3, 9.1) consume alcohol (≥ four days/week) no 28.3 ± 7.3 87.5 ± 16.8 yes 33.8 ± 4.9^ 5.5 (-1.0, 12.0) 95.0 ± 14.7 7.5 (-7.5, 22.5) completed high school no 28.9 ± 7.9 90.6 ± 15.8 yes 28.0 ± 6.8 -0.9 (-2.9, 1.2) 84.8 ± 17.3* -5.9 (-10.5, -1.2) employed no 27.5 ± 7.1 85.1 ± 17.0 yes 31.1 ± 7.2** 3.6 (1.4, 5.8) 94.2 ± 14.4** 9.0 (4.0, 14.1) high ses no 27.8 ± 7.4 86.5 ± 15.7 yes 29.9 ± 6.9* 2.1 (0.001, 4.3) 90.0 ± 18.6 3.5 (-1.5, 8.4) smoker no 28.5 ± 7.2 87.7 ± 16.8 yes 29.1 ± 10.3 0.6 (-5.4, 6.6) 86.8 ± 16.5 -0.9 (-14.6, 12.9) snuff consumption no 28.4 ± 7.5 87.3 ± 16.9 yes 29.6 ± 3.9 1.2 (-3.3, 5.7) 94.0 ± 14.0 6.7 (-3.6, 16.9) sleeps < six hours/night no 28.2 ± 7.15 88.0 ± 15.8 yes 31.3 ± 8.7^ 3.2 (-0.5, 6.7) 84.4 ± 25.5 -3.6 (-12.0, 4.8) sleeps ≥ nine hours/night no 28.8 ± 7.25 86.9 ± 17.7 yes 28.2 ± 7.4 -0.5 (-2.6, 1.5) 88.3 ± 16.0 1.4 (-3.3, 6.1) data presented as mean ± sd for t-test or β (95%ci) for the univariate linear regression. *p<0.05, **p<0.005, ^non-significant trend (p<0.2) body mass index (bmi). wc, waist circumference; ses, socioeconomic status; gpaq, global physical activity questionnaire. table 3. multivariable linear regression models showing correlates of simple anthropometry exposure bmi wc sbp dbp age 0.2 (0.001) 0.3 (<0.0001) 0.2 (0.003) pc2 0.1 (0.04) bmi 0.7 (<0.0001) 0.2 (0.002) 0.3 (<0.0001) completed high school -0.1 (0.01) ses 0.2 (0.008) hypertensive 0.2 (0.002) sleep (≥nine hours/night) -0.2 (0.02) -0.2 (0.01) vif for the model 1.1 1.0 1.1 1.1 r2 for the model with p-value 0.2 (<0.0001) 0.6 (<0.0001) 0.2 (<0.0001) 0.2 (<0.0001) bmi, body mass index; wc, waist circumference; sbp, systolic blood pressure; dbp, diastolic blood pressure; vif, variance inflation factor, pc2, beer and sweetened tea (derived from principal component analysis). the reference groups for multivariable linear regression models were non-hypertensive, night-time sleep duration 7-8 hours per night, and incomplete high school and primary school. original research 5 sajsm vol. 30 no. 1 2018 is a novel finding in this population, suggesting protection against hypertension with longer night-time sleep. acknowledgments: the authors acknowledge the participants and chief of the tshino nesengani (mukondeleli) village, limpopo province, south africa. one of the authors is supported by the south african dst/nrf centre of excellence in human development. another author is supported in part by the south african nrf through grant number 113366. any opinion, finding and conclusion or recommendation expressed in this material is that of the author(s) and the nrf does not accept any liability in this regard. conflict of interest: no conflicts of interest. references 1. ncd risk factor collaboration (ncd-risc) – africa working group. trends in obesity and diabetes across africa from 1980 to 2014: an analysis of pooled population-based studies. int j epidemiol 2017;46(5):1421-1432. [doi: 10.1093/ije/dyx078] 2. okop kj, levitt n, puoane t. factors associated with excessive body fat in men and women: cross-sectional data from black south africans living in a rural community and an urban township. plos one2015;10(10): e0140153. [doi: 10.1371/journal.pone.0140153] 3. goedecke jh, mtintsilana a, dlamini sn, et al. type 2 diabetes mellitus in african women. diabetes res clin pract 2017;123:87-96. [doi: 10.1016/j.diabres.2016.11.017] 4. ezeh a, oyebode o, satterthwaite d, et al. the history, geography, and sociology of slums and the health problems of people who live in slums. lancet 2017;389(10068):547-558. [doi: 10.1016/s0140-6736(16)31650-6] 5. malik vs, popkin bm, bray ga, et al. sugar-sweetened beverages and risk of metabolic syndrome and type 2 diabetes: a meta-analysis. diabetes care 2010;33(11):24772483. [doi: 10.2337/dc10-1079] 6. national department of health, statistics south africa, south african medical research council, et al. south africa demographic and health survey 2016: key indictors report. pretoria: stats sa; 2017. http://www.statssa.gov.za/publications/report%2003-0009/report%2003-00-092016.pdf 7. pretorius s, stewart s, carrington mj, et al. is there an association between sleeping patterns and other environmental factors with obesity and blood pressure in an urban african population? plos one. 2015;10(10):e0131081. [doi: 10.1371/journal.pone.0131081] 8. bull fc, maslin ts, armstrong t. global physical activity questionnaire (gpaq): nine country reliability and validity study. j phys act health 2009;6(6):790-804. [pmid:20101923] 9. hedrick ve, savla j, comber dl, et al. development of a brief questionnaire to assess habitual beverage intake (bevq-15): sugar-sweetened beverages and total beverage energy intake. j acad nutr diet 2012;112(6):840-849. [doi: 10.1016/j.jand.2012.01.023] 10. buysse dj, reynolds cf 3rd, monk th, et al. the pittsburgh sleep quality index: a new instrument for psychiatric practice and research. psychiatry res 1989;28(2):193-213. [pmid:2748771] 11. gradidge pj, norris sa, micklesfield lk, et al. the role of lifestyle and psycho-social factors in predicting changes in body composition in black south african women. plos one 2015;10(7):e013291. [doi: 10.1371/journal.pone.0132914] 12. micklesfield lk, munthali rj, prioreschi a, et al. understanding the relationship between socio-economic status, physical activity and sedentary behaviour, and adiposity in young adult south african women using structural equation modelling. int j environ res public health 2017;14(10):pii: e1271. [doi: 10.3390/ijerph14101271] 13. spaeth am. additional sleep duration associates with improved blood sugar regulation. sleep 2015;38(5):663-664. [doi: 10.5665/sleep.4648] 14. fang j, wheaton ag, keenan nl, et al. association of sleep duration and hypertension among us adults varies by age and sex. am j hypertens 2012;25(3):335-341. [doi: 10.1038/ajh.2011.201] 15. peltzer k, pengpid s. sleep duration, sleep quality, body mass index, and waist circumference among young adults from 24 lowand middle-income and two high-income countries. int j environ res public health 2017;14(6): pii:e566. [doi:10.3390/ijerph14060566] km_c227-20180517092505 pg78.indd i have just finished reading a book titled samaritan of south african rugby, written by pat tebbutt. it is an historical account of the chris burger/petro jackson players’ fund which was established to support rugby players who have sustained serious injuries. the story starts in august 1980, the day western province played the free state in bloemfontein. following a robust loose scrum, all the players involved got to their feet except chris burger of western province, who lay motionless on the ground with a broken neck. by 4 am the following morning he had died. this tragic event inspired his colleagues, led by the western province captain morné du plessis, to create the chris burger players’ fund to raise money to support injured players. thirty years later over 400 seriously injured players have been assisted by the fund at a cost of more than 30 million rand. as the fund evolved, and the ethos for making rugby safer grew, there was need to actively promote an injury prevention programme designed to lower the risk of injury. rather than re-invent the wheel, the leaders of the successful rugbysmart programme in new zealand and smartrugby programme in australia were consulted. both these programmes were designed to achieve the goals of making rugby safer. as a result boksmart was launched. boksmart adopted the principles of these two existing programmes and then customised the content to serve the needs of south african rugby. the programme has grown exponentially. since the inception of boksmart in mid2009, over 10 000 coaches have been trained in principles of safe rugby. in addition, boksmart has established a website rich with evidence-based information on matters pertaining to rugby (www. boksmart.com). topics range from physical preparation for rugby to the on-field management of serious injuries. all articles are freely available and are designed to serve and educate anyone involved in rugby. this preamble brings me to the link to this edition of the journal. boksmart commissioned the review paper on concussion, written by dr jon patricios – this review provides the most current best practice principles for managing concussion. the paper explains how a series of international consensus statements, which started in 2001, accelerated the understanding of the management of this injury. while there is still much to learn, the field has progressed significantly in the last decade. the remainder of the journal has an assortment of interesting papers. for example, a study on scuba diving describes how divers neglect their auditory systems. the study shows that there needs to be more education on ear problems following a dive, as divers do not generally have sufficient knowledge to manage the conditions properly. then there is a case study on the paget-schroetter syndrome, followed by a short review of the topic. although not a common condition it has the potential to be serious and if detected early and managed properly can reduce the recovery time significantly. next there is an interesting paper on the most common physical therapy modalities for the treatment of whiplash. the paper shows that there is no standard treatment and recommends the establishment of a best practice protocol. the ‘editor’s choice’ paper, published with permission from the british journal of sports medicine, describes a novel test which has the potential to detect symptoms of overreaching and overtraining. although further research needs to be done, this test is innovative and has the potential to be practical in managing high-performance athletes. as this is the last edition of the south african journal of sports medicine for 2010 it is appropriate to thank all the people that make this journal possible. firstly, the reviewers should get applauded. they generally do an excellent job, with no recognition or reward. it is a time-consuming and difficult task. i know some of the authors get frustrated at the detailed reviews, but the quality of paper that finally gets accepted for publication is always much better than the original form of the paper. next, the staff of the health and medical publishing group are thanked. their efficient, friendly service makes the job of this editor much easier to manage! mike lambert editor-in-chief turning tragedy into triumph a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial 78 sajsm vol 22 no. 4 2010 2 sajsm vol 24 no. 1 2012 editorial translation of research sports medicine and exercise science has blossomed as a discipline. for example, in the 1960s the understanding of fatigue was restricted to changes in substrates and metabolites that could be measured in a muscle biopsy. the explanation of fatigue revolved around these measurements and interventions were planned using this limited k n ow l e d ge . now, ove r 4 0 years later, the functioning of the brain and muscles can be measured simultaneously during a bout of exercise and therefore the understanding of fatigue has both broadened and deepened. it goes without saying that the interventions have become more enriched with a much stronger impact. there are many other examples showing that the knowledge database has increased exponentially as the discipline has evolved. however, just like other branches of science, the gap between the knowledge of a topic and the translation of this knowledge into action is still wide. in south africa two sports are setting the trend in translating research into action. firstly, the south african rugby union has established a medical and scientific committee that has the mandate to incorporate principles of best practice into player management. the goal is to ensure that the game is made safer for the players – the boksmart programme (www.boksmart.com) is aligned to this goal and implements training courses around the country. indeed, over 20 000 coaches and referees have been trained since the programme began in 2008. also about 50 evidence-based papers, on a range of topics from nutrition for rugby, to return-to-play after injury, are available on their website. the second example is cricket. although they are a few years behind rugby in terms of developing their medical and scientific infrastructure, a full-time research officer has recently been appointed by cricket sa to co-ordinate and stimulate research around the country. the goal is to foster communication between the coaches, players and researchers to ensure that relevant questions are answered and any intervention programmes, as a result of this research, are implemented in a systematic way. both these sports have the infrastructure now to translate research in action – the results of which will most certainly be noticed from a performance perspective, and also from a player welfare perspective. the bar has been raised; other sports need to establish their own similar structures which encourage multi-disciplinary collaboration and the capacity to translate research into action. the same concerns exist in the health and wellness field. although much is known about the value of exercise and the risk of physical inactivity, countries all over the world are faced with similar challenges of making their inhabitants more physically active. this is not a medically or scientifically based problem. this is based on the fact that more information about the value of exercise-induced adaptations is not going to be the deal-breaker or catalyst that encourages people to lead more physically active lives. although certain medical insurance companies are setting the trend and providing rewards and incentives for their members who can demonstrate their adherence to a physically active lifestyle, the problem requires holistic input from a variety of sources. for example, town planners need to plan suburbs to make it easier and safer for people to cycle to work. they need to provide more parks for leisure time activities. schools need to join in and create opportunities and facilities for their pupils to engage in exercise. businesses need to provide facilities that make it easier for their staff to exercise during breaks, and then reward employees who remain physically active. providing everyone shares a common goal this next step should not be too difficult to implement. this edition of the journal has a range of topics which fit somewhere on the continuum between basic research and implementation. for example, there are two studies on injuries in cricket players, and a study on trail runners. there is a commentary on physical activity as a risk factor for non-communicable disease, a commentary on cerebral damage in diving and an excellent article on fatigue that was previously published in the british journal of sports medicine. i’m sure the papers will provoke ideas of ways in which the outcomes of the papers can be implemented. the format of the journal is changing slightly to align it with the requirements for the pubmed database. this is the first step in the process of having the contents published, which we anticipate will happen sooner rather than later. mike lambert editor-in-chief 66 sajsm vol 23 no. 2 2011 editorial 66 sajsm vol 23 no. 3 2011 the axiom ‘you cannot manage what you don’t measure’ has been applied in business for several years. although the origins of the phrase are not clear, it has been adopted as a general management principle in many different spheres of society. in the context of business this statement stresses the importance of collecting data about profits, staff productivity and consumer trends to ensure that the business adapts with the changing demands and is managed in an efficient way. collecting information regularly enables decisions to be made which are aligned to the changing landscape. these decisions are based on evidence and have a greater probability of being correct compared with decisions based on intuition. without this ability to forecast it would be very difficult to manage the company in a profitable direction. we see the same application of this principle in medical insurance companies, which employ actuaries to analyse their clients’ claim records in an attempt to predict trends and maximise profit. indeed, this type of analysis has resulted in some of the more proactive companies promoting physical activity as a means of reducing medical costs. similar examples of management strategies being based on measurement can be found in all types of business. the principle of ‘you cannot manage what you don’t measure’ can also be applied to sports medicine and exercise science. in fact, this approach should be assumed to be part of a best practice approach of managing patients and sports participants. there are many examples supporting this view, ranging from measuring muscle function during rehabilitation after surgery to managing fatigue in high-performance athletes. while the concept of measurement is easy to understand, the application and interpretation of a measurement is less well understood. the difficulties of applying and interpreting measurement were highlighted in an excellent paper titled ‘test validation in sport physiology: lessons learned from clinimetrics’. 1 the authors discuss the field of clinimetrics which focuses on the quality of clinical measurements. this process defines a useful measurement as being reliable, valid and responsive to intervention. furthermore, the implications of changes in the measurement should be fully understood. in other words how many units of change are necessary for the change in the measurement to be regarded as clinically relevant or meaningful? data are available, for example, showing that a 21% gain in the one-repetition-maximum squat exercise is associated with a 2.3% improvement in sprint performance. 2 therefore, while it may be shown in the laboratory that a 5% increase in squat performance is statistically significant, the relevance of this with regards to sprinting speed is trivial. to reach a conclusion about the merits of the change in the measurement, the measurement error needs to be quantified. measurement error is the variation that occurs if the measurement were conducted on repeated occasions. for the measurement to be useful the measurement error (also referred to as ‘noise’) needs to be considerably less that the factor that is being measured (the ‘signal’). the precision of the measurement gets reduced the closer the ‘noise’ is to the smallest worthwhile ‘signal’.there is no doubt that the discipline of sports medicine and exercise science needs to be more vigilant about applying the principles of clinimetrics. without this basic knowledge management of the athlete may be misguided, money will be spent inappropriately and the athletes will bear the brunt of this by failing to reach their potential. to move the discipline forward all health professionals and scientists who work with athletes need to make a concerted effort to apply the principles of clinimetrics. firstly, only tests which have undergone evaluation for the determination of their reliability, validity and measurement error should be used. this applies to tests used in clinical rehabilitation through to performance testing for high-performance athletes. secondly, the minimum worthwhile measurement for each test should be known. this is important for determining whether a change in the measurement is relevant or not. thirdly, the extent to which a change in measurement in a test translates into the variable that it is designed to measure should also be known. fourthly, a simple approach can be applied to the changes in the measurement to decide whether the change in the measurement is beneficial, trivial, harmful, or unclear. 3 the logic behind this approach should be discussed with the coaches and medical support staff so that everyone is aligned in the interpretation. this will make the management of the measurement much easier for everyone involved. failing to fulfill these 4 points will result in an inability to use the measurements constructively to improve the quality of the management. this edition of the journal coincides with the 14th biennial south african sports medicine association conference. the quality and diversity of the abstracts confirm that sports medicine and exercise science is in a healthy state in south africa! mike lambert editor-in-chief 1. impellizzeri fm, marcora sm. test validation in sport physiology: lessons learned from clinimetrics. int j sports physiol perform 2009;4(2):269-277. 2. young wb. transfer of strength and power to training to sports performance. int j sports physiol perform 2006;1(2):74-83. 3. hopkins wg. how to interpret changes in an athletic performance test. sportscience 2004;8:1-7. measure, so you can manage c p d q u e s t io n n a ir e sajsm instructions 1. read the journal. all the answers will be found there. 2. go to www.cpdjournals.co.za to answer questions. accreditation number: mdb001/008/01/2011 (clinical) questions december 2012 cpd questionnaires must be completed online via www.cpdjournals.co.za. after submission you can check the answers and print your certificate. 1. true (a) or false (b): the evidence for the increased risk of knee and hip osteoarthritis in former professional soccer players is unconvincing. 2. true (a) or false (b): injuries that occur in the immature skeleton produce similar pathologies to those that occur in the adult skeleton. 3. true (a) or false (b): the rupture of the achilles tendon occurs most frequently in the age group 30 39 years, which is surprising because this age does not coincide with the time of maximum sport participation. 4. true (a) or false (b): top-level tennis players do not regularly have a ‘tennis elbow’, unlike the beginners or technically poor exponents of the sport. 5. true (a) or false (b): ‘return to play’ is often the key driver for managing an injury of an elite athlete. this does not always consider the long-term health of the athlete. 6. true (a) or false (b): high levels of participation in a sport may not be the risk factor for injury but the history of how the athlete reached that level may be. 7. true (a) or false (b): the long-term athlete development model describes windows of opportunity which are critical periods of development for specific attributes. 8. true (a) or false (b): a criticism of the ‘windows of trainability’ concept is that it is primarily based upon psychological principles. 9. true (a) or false (b): the majority of the work that forms the basis of the developmental model for sport participation originates from qualitative interviews, training questionnaires and retrospective/ quantitative interviews. 10. true (a) or false (b): periods of increased adaptation for the physical attribute of ‘speed’ occur between the ages of 5 and 9 years. 11. true (a) or false (b): shoulder injuries in rugby account for the second most loss in time (days) for players, after lower-limb knee injuries. 12. true (a) or false (b): the state of ‘anxiety’ has been negatively associated with an increased risk of injury in sport. 13. true (a) or false (b): almost one-third of rugby players at the club level can be expected to have a shoulder injury during the season. 14. true (a) or false (b): rugby players who had shoulder injuries had much lower anxiety scores than those players who did not get injured. 15. true (a) or false (b): rhabdomyolysis is preceded by muscle weakness, muscle stiffness, symptoms of myalgia, swelling, tenderness and tea-coloured urine. 16. true (a) or false (b): rhabdomyolysis can be triggered by mechanical injury, ischaemia, infections, genetic alterations to drugs and toxins. 17. true (a) or false (b): corticosteroid-induced myopathy is a disease that mainly causes weakness of the proximal muscles of the upper and lower limbs and to the neck flexors. 18. true (a) or false (b): the ‘vuka south africa – move for your health’ campaign is an example of an initiative adopted by national government, promoting motorised transport. 19. true (a) or false (b): in 2002, the world health organization’s report on reducing risks and promoting healthy living recognised physical inactivity as one of the major modifiable risk factors for developing noncommunicable diseases and global mortality and morbidity, along with tobacco use, unhealthy eating and obesity, and excessive alcohol intake. 20. true (a) or false (b): the south african youth risk behaviour survey found that more than one-third of all adolescents report insufficient levels of physical activity. we are pleased to announce that effective from this month, the number of ceus per test has been increased to 5. introduction similar to the increases seen in athletic participation within the united states, female athletic participation continues to increase worldwide. an examination of the participation of women in the olympic games over the last century appears to support this. female participation has steadily increased, most dramatically over the past 50 years. the most recent summer olympics in beijing (2008) saw the highest rate of female participation with a total of 4 746 women participating, representing a record 42% of athletes. women remain underrepresented in sport in south africa, but consistent and progressive rates of participation are being appreciated throughout the country. as rates of female participation continue to increase throughout the country, it is important to consider the unique health challenges that female athletes may encounter. for most female athletes, sports participation is a positive experience, providing improved physical fitness, enhanced selfesteem and better physical and mental health. 1 however, this increased activity has also led to the emergence of a unique combination of medical problems and injuries specific to the female athlete. this includes a unique triad to conditions specific to the female athlete that include energy availability, menstrual function and bone mineral density. definitions in 1992, the american college of sports medicine (acsm) recognised the association of three distinct entities with female athletes. the female athlete triad was originally defined as the combination of disordered eating, amenorrhoea and osteoporosis found in physically active girls and women. 2 further research since then proved these entities to be far too narrow in scope, existing only at the extreme endpoint of the disorder’s spectrum. 3 by 2007, the acsm revised position statement modified the three components of the triad into energy availability, menstrual function and bone mineral density. 4 each of these components consists on a continuum from healthy to subclinical to pathological. energy intake from diet is necessary for various physiological functions. energy expenditure is the energy expended by the body during normal daily activities and exercise training. energy availability defines the amount of energy remaining for physiological functions after expended from physical activity. decreased caloric consumption and/or increased exercise energy expenditure results in low energy available for normal physiology functions, including cellular maintenance, thermoregulation, growth and reproduction. clinical eating disorders, namely anorexia nervosa, bulimia nervosa and eating disorders not otherwise specified, exist on the extreme end of this category. however, these conditions carry a largely psychiatric component for diagnosis. 5 a larger population of female athletes practise unhealthy eating and weight control behaviours with significant impact on their health without the psychiatric element. such subclinical eating disorders include prolonged fasting, low caloric diets, binge eating, purging, or the review the female athlete triad: a current concepts review christopher a george (md) james p leonard (md) mark r hutchinson (md) university of illinois at chicago, department of orthopaedic surgery, chicago, il 50 sajsm vol 23 no. 2 2011 correspondence: mark r hutchinson university of illinois hospital at chicago department of orthopaedic surgery 835 s wolcott ave m/c 844 chicago, il 60612 e-mail: mhutch@uic.edu abstract female athletic participation continues to grow throughout the world. this has many positive effects on health and well-being, but it has also led to a unique set of health problems. the female athlete triad was first described in 1992 by the american college of sports medicine, consisting of disordered eating, amenorrhoea and osteoporosis. an updated position stand was released in 2007 that modified the components of the triad to energy availability, menstrual function and bone mineral density. this article reviews the current definitions of the triad components, epidemiology, pathophysiology, diagnosis and treatment. each of the components of the triad exists on a continuum from healthy to pathological. low energy availability, from either dietary restriction or increased expenditure, is the factor that leads to the pathological states of menstrual function and bone mineral density. athletes especially at risk are those in sports requiring leanness or low body weight. prevention and early recognition of triad disorders is crucial to ensure timely intervention and treatment. treatment is centered on restoring energy availability to adequate levels (30 kcal.kg -1 .d -1 ) to re-establish normal metabolic functioning. all those who work with female athletes must remain vigilant in the education, recognition and treatment of athletes at risk. continued research and knowledge of the triad disorders aids the development of prevention and treatment strategies to allow women to continue to enjoy the benefits of regular exercise and physical activity throughout their lives. sajsm vol 23 no. 2 2011 51 utilisation of diet pills, laxatives and other supplements. other athletes unknowingly fail to meet their considerable exercise energy requirements due to time constraints, food availability issues or lack of appropriate nutritional knowledge. 6 amenorrhoea is the absence of menstrual cycles, and can be subdivided into primary and secondary amenorrhoea. primary amenorrhoea is the absence of menarche by age 15, whereas secondary amenorrhoea is an interruption of menses for greater than 3 months after the initiation of menarche. 7 the acsm updated position stand on the female athlete triad recognised other menstrual irregularities that cause an adverse effect to the female athlete’s health. 4 thus, the term menstrual dysfunction was employed as a component of the female athlete triad, which includes luteal suppression, anovulation and oligomenorrhoea in addition to primary and secondary amenorrhoea. oligomenorrhoea describes a prolonged menstrual cycle greater than 35 days. 8 both luteal suppression and anovulation are asymptomatic conditions, associated with either a shortened luteal phase or lack of ovulation respectively. osteoporosis is a decrease in bone mass that increases the risk of fracture. 9 this may be due to age-related decreases in bone mass, or the result of inadequate bone accumulation during growth and development resulting in a lower peak bone mass being attained. the world health organization (who) criterion for diagnosing osteoporosis is a bone mineral density more than 2.5 standard deviations below the mean of young adults. 10 utilisation of this t-score was based on epidemiological data relating bone mineral density to fracture risk in postmenopausal women, 11,12 thus it lacks external validity for evaluating adolescent or premenopausal women. in 2005, the international society for clinical densiometry (iscd) recommended that bone mineral density for premenopausal women and children be expressed as a z-score. a z-score greater than or equal to 2.0 standard deviations below the mean of ageand sex-matched controls is defined as ‘low bone density below the expected age range’. 13,14 together the iscd and acsm defined osteoporosis in premenopausal women as having this low z-score along with secondary clinical risk factors, including chronic malnutrition, eating disorders, hypogonadism, glucocorticoid exposure and previous fractures. 4,13,14 epidemiology the prevalence of female athletes with abnormalities in energy availability, menstrual function and/or bone mineral density varies tremendously between studies. reported data show a range of 1 62% of female athletes with an eating disorder, 2,15 6 79% with menstrual dysfunction, 2,3,16 and 0 50% with low bone mineral density. 17 several factors have contributed to these broad results, including the wide range and ever-changing definitions of each component of the female athlete triad. utilising the strict dsm-iv diagnosis for clinical eating disorders yields a prevalence between 1% and 3%, 18 whereas the more ambiguous term ‘disordered eating’ opens up the diagnostic criteria, yielding larger prevalence outcomes between 15% and 62%. 1 similarly, the expanded definition of menstrual dysfunction to include oligomenorrhoea, luteal suppression and anovulation has seen prevalence increase from 6% to as high as 79%. 16,19 finally, studies utilising the who classification for bone mineral density found 22 50% of patients with osteopenia, and virtually 0% having osteoporosis. 17 the new iscd criterion utilizing z-scores identified 10.7% of female athletes to have low bone mineral density below the expected age range. 20 other aspects involved in the investigation of the female athlete triad result in an imprecise measurement of prevalence. diagnosis of low energy availability typically involves self-questionnaires. most questionnaires are designed for clinical eating disorders, such as the eating disorders inventory (edi or edi-2) or the eating attitude test (eat), 21 and focus mostly on the psychiatric component of the disease. they do not take into account other subclinical causes of low energy availability, including excess exercise energy expenditure and abnormal eating behaviours. this can be better assessed with documentation of energy balance through food logs and activity records. however, both evaluations require self-reporting, with inherent limitations due to underreporting of symptoms. 1 the heterogeneity of the population being investigated for the female athlete triad has also created discrepancies in prevalence. the age of an athlete significantly affects their risk for each component of the triad, as does their stage in growth, development and menarche. thus, comparing athletes over a wide range of ages during adolescence and pre-adulthood becomes problematic. in addition, because females develop at different rates, comparing them at similar ages can also cause difficulties. the level of competition also affects the epidemiological studies of the female athlete triad. comparison of elite athletes, collegiate athletes and recreational athletes has shown an increase risk for components of the female athlete triad with increasing level of competition. a meta-analysis of 34 studies with 2 459 athletes found an increased risk of disordered eating with elite athletes, and that non-elite athletes, especially those in high school, were somewhat protected. 22 early start of sport-specific training and dieting, a sudden increase in training volume, and sports-related injury are also risk factors for the female athlete triad more commonly seen in higher-level athletics. 23 the increased pressure for winning by the athletes, as well as coaches, parents and society in general, places these athletes at higher levels of competition at increased risk for behaviours associated with the female athlete triad. 1 different sports have different risk factors for the individual components of the female athlete triad. low energy availability is more commonly seen in sports that emphasise a lean physique or low body weight (table i). 2 byrne et al. 24 identified 31% of elite female athletes in ‘thin-build’ sports to have an eating disorder compared with 8% in the ‘normal-build’ athletes. thin-build athletes are those involved in sports emphasising leanness or low body weight (ballet, gymnastics, long distance running, swimming and diving), where normal-build athletes are those in sports with less emphasis on leanness (basketball, volleyball, hockey, softball). 24 menstrual dysfunction is more common in endurance sports such as running, with prevalence up to 69%. 25,26 high-impact sports such as basketball, volleyball and gymnastics 20,27,28 are associated with higher bone mineral density than lower-impact sports such as table i. sport-specific risks to low energy availability category examples sports subjectively scored dance, figure skating, diving, gymnastics, aerobics sports emphasising low body weight distance running, cycling, crosscountry skiing sports requiring body contour-revealing clothing volleyball, swimming, diving, cross-country running, crosscountry skiing, track, cheerleading sports with weight categories horse racing, martial arts, wrestling, rowing sports emphasising prepubertal body habitus figure skating, gymnastics, diving running and swimming. 29 consequently, studies examining single sports may either overestimate or underestimate the true overall prevalence of the female athlete triad. despite all the difficulties reporting on the female athlete triad, including inconsistent definitions, methodological issues and the heterogeneity of the population, three studies establish prevalence for the simultaneous diagnosis of all three components of the female athlete triad 30-32 these studies utilised large, heterogeneous samples of athletes as well as a more validated definition of low energy availability, menstrual dysfunction and low bone mineral density. disordered eating and menstrual dysfunction were determined from a questionnaire, while bone mineral density was evaluated via dualenergy x-ray absorptiometry (dxa). the resultant prevalence was between 1.2% and 4.3% of female athletes for all three components. however, these values are likely underrepresented because neither low energy availability nor subclinical menstrual disorders, including luteal suppression, anovulation and oligomenorrhoea, were part of the diagnostic criteria. also, as discussed previously, self-reporting has inherent bias. finally, although the prevalence is low for all components of the triad, one study 31 found 6% of female athletes had two components of the female athlete triad and 18 24% had one component. pathophysiology in addition to redefining the components of the female athlete triad, the acsm focused on the pathogenesis of the female athlete triad. the majority of the current research on the female athlete triad centres on low energy availability as the key entity underlying the entire process. a specific aetiology has not been identified regarding the pathogenesis of eating disorders or low energy availability. 33 there likely is a complex relationship between social, cultural, demographic, environmental, biology, psychological and behavioural factors. 34 controversy exists regarding whether athletes have a higher prevalence of disordered eating behaviours when compared with non-athletes, with some studies showing increased prevalence in the athletic population, 22,35,36 while others show no difference. 37,38 however, there is evidence suggesting athletes face sportspecific pressures that may trigger eating disorders in vulnerable athletes. as discussed previously, sports with emphasis on low body weight place these athletes at increased risk for developing a clinical eating disorder. in addition, increased training and practice associated with organised athletics may lead to inadvertent low energy availability. experiments have shown that dietary restriction increased hunger, but similar levels of energy deficiency by increased exercise expenditure did not increase appetite. 39 as a result, athletes unknowingly do not increase their energy intake due to increased exercise expenditure due to a lack of a physiological response. 40 energy availability is not just related to diet and exercise, but also dependent on other hormonal and physiological processes. two different hormones, leptin and ghrelin, have been identified as potential regulators of metabolic rate and energy homeostasis. the hormone leptin regulates the resting metabolic rate, and has been proposed as a marker of nutritional status. leptin is decreased in athletes with disordered eating and amenorrhoea. 41 a leptin value of 1.85 mg has been identified as a minimum value to maintain a normal menstrual cycle. 41 ghrelin is a hormone produced in the stomach and gastrointestinal tract that acts as a metabolic signal for hunger and energy homeostasis. de souza et al. 42 showed high levels of ghrelin in amenorrhoeic women indicate an energy deficit. ghrelin may also play a physiological role in reproductive function via actions on the luteinising hormone (lh) pulsatility. 43 increased physical activity has been linked to the cessation of menses. 16 this has been found as a result of a disruption in the pulsatile secretion of lh by the pituitary gland, which is caused by a disruption earlier in the pulsatile secretion of the gonadotropinreleasing hormone by the hypothalamus. 44 in multiple studies, loucks showed that low energy availability is at the root of hypothalamic menstrual dysfunction. 45-47 the threshold of energy availability necessary to maintain normal menstrual function in 30 kcal.kg -1 lean body mass per day. 45 strenuous training alone is not enough to disrupt menstrual function, unless it is also accompanied by dietary restriction. normal cycles can be restored with increasing dietary intake; however, this is only accomplished with sustained increased intake, not simply one day of aggressive refeeding. 46 altered bone mineral density is related to deficiency in the hormones oestrogen and progesterone, as well as caloric deprivation and inadequate calcium intake. the most important function of oestrogen on bone health is its suppressing effect of osteoclast activity. 48 bmd declines as the number of missed menstrual cycles accumulates and these losses may not be fully reversible. 49 a study by ihle and loucks showed that low energy availability may have a direct effect of bone. 50 they demonstrated markers of bone formation and resorption changed negatively within 5 days in sedentary women exposed to low energy availability through dietary restriction or increased exercise energy expenditure. it is plausible to expect similar results to be seen in an athletic population. additional work by zanker has shown that low bmi and an oestrogen deficiency were associated with disruption of bone formation in amenorrhoeic women. 51 however, there was a lack of correlation between serum levels of bone formation markers, bmi and serum oestradiol concentration in the eumenorrhoeic athletes, suggesting that there may be a threshold value of bmi, or serum oestradiol concentration, above which bone formation is not influenced by either of these variables. in fact, markers of bone formation are low in athletes with menstrual dysfunction, suggesting that low bone formation is a result of undernutrition. additional studies have indicated that low energy availability affects other metabolites and hormones, such as insulin, growth hormone, insulin-like growth factor-1, cortisol and thyroid hormone. 52 these are all important for optimal bone health and metabolism independent of a hypo-oestrogenic state. health consequences the body compensates for low energy availability by decreasing the resting metabolic rate, resulting in decreased energy to other normal physiological mechanisms, such as cellular maintenance, thermoregulation, growth and reproduction. thus, although a stable body weight may be maintained, the health of the athlete is adversely affected. sustained low energy availability can have significant effects on health. undernutrition impairs both menstrual and skeletal heath. 53 additionally, several studies have shown medical effects and physical symptoms involving the dermatological, cardiovascular, endocrine, gastrointestinal, renal and central nervous systems (table ii). 33,53-55 montero et al. 56 examined the effect of low energy availability on the immune system of the female athlete (fig. 1). increased exercise combined with low calorie intake seems to decrease immunocompetence, resulting in decreased endurance, decreased performance and increased chance of subclinical and clinical infections. the effect that low energy availability has on athletic performance varies depending on the severity and duration of the low energy state, 52 sajsm vol 23 no. 2 2011 sajsm vol 23 no. 2 2011 53 as well as the physical demands of the sport. 57 longer durations of restricted energy availability are associated with more dramatic negative effects on performance. 57 likewise, athletes in endurance sports with high energy demands (distance running, swimming, cycling, basketball) show more effects on performance than athletes in lower energy demand sports (gymnastics, diving, weightlifting). the consequences of menstrual dysfunction have been well documented and include infertility, decreased immune function, increased cardiovascular risk factors and decreased bone mineral density with its associated increased risk of premature osteoporosis. 58 it should be emphasised to athletes that menstrual dysfunction is not a normal response to athletic training. athletes may show little concern for disruption of their cycles and may even ‘appreciate the break’. however, this should be viewed as a clear indication that health is being compromised. an athlete’s bone mineral density is a reflection of her cumulative history of energy availability and menstrual status, in combination with genetics and other environmental factors. it is important to always consider the current bone mineral density status and where it is moving along the spectrum. stress fractures occur more frequently in females who display menstrual irregularities and/or low bone mineral density. 59,60 a premenopausal fracture not related to a significant traumatic event is a strong predictor for postmenopausal fractures. 61 even with restoration of adequate energy availability and regular menses the loss of bone mineral density may not be fully reversible. screening and diagnosis of triad disorders screening for and diagnosis of the triad disorders can be challenging due to the symptoms and health consequences not always being readily apparent. a high degree of suspicion and an understanding of the relationship between the triad components are critical to diagnosis. many of the affected athletes are involved in those sports requiring leanness or thinness as an advantage in performance; however, individuals participating in any sport or regular physical activity are also at risk. additionally, individuals of all levels may be at risk, not just the elite population. optimal screening times are during pre-participation physicals and during annual heath exams. other opportunities present when athletes are evaluated for related problems. any time an athlete presents with one component of the triad, they should be assessed for the others. energy availability/disordered eating a high index of suspicion is necessary for the recognition and diagnosis of disordered eating behaviours. psychological or behavioural characteristics may alert the physician or other member of the health care team. examples include: anxiety with eating or weight gain, unusual dieting behaviour, binging or secretive eating, social withdrawal, abuse of laxatives or other weight loss medications and over-exercising. 62 additionally, recognition of physical symptoms likely related to malnutrition and/or purging behaviours may be seen. 62 weight loss methods may include restriction of food intake, fasting, self-induced vomiting, diet pills, laxatives, diuretics and excessive exercise. 62 physical exam is important in the recognition of eating disorders, and should start with height, weight and vital signs. orthostatic hypotension should also be assessed. other physical findings include cold or discoloured hands and feet, hypercarotenaemia, lanugo hair and parotid gland enlargement. laboratory assessment should initially include a complete blood count with differential, chemistry profiles, erythrocyte sedimentation rate, c-reactive protein, thyroid function studies (and other sex steroid hormones depending on physical findings) and a urinalysis. an electrocardiogram should also be done to evaluate for any arrhythmias and prolongation of the qt interval. 63 table ii. physical symptoms of athletes with eating disorders dermatological/dental cardiovascular endocrine gastrointestinal hair loss bradycardia hypoglycaemia swollen parotid glands lanugo hair hypotension delayed onset of puberty constipation/diarrhoea dorsal hand callus or abrasions menstrual dysfunction postprandial distress dental and gum problems stress fractures renal dehydration oedema electrolyte disturbances hypokalaemia muscle cramps metabolic alkalosis cns/other significant weight loss frequent weight fluctuations extreme fatigue muscle weakness hyperactivity anaemia fig. 1. consequences of increased exercise and a low bmi in the female athlete. 54 sajsm vol 23 no. 2 2011 menstrual dysfunction similar to identification of eating disorders, a high degree of suspicion, thorough history taking and physical exam are important in identification of menstrual dysfunction. menstrual dysfunction commonly accompanies disordered eating, but if it continues after weight is restored to within 10% or normal, further workup for amenorrhoea is indicated. patients with functional hypothalamic amenorrhoea often have a normal physical exam, but may show vaginal atrophy on pelvic exam if hypo-oestrogenism is present. laboratory evaluation for secondary amenorrhoea should include a pregnancy test, gonadotropin measurement (fsh, lh), probating and thyroid studies. if there is evidence of androgen excess on physical exam, free testosterone and dehydroepiandrosterone sulfate may be obtained. additional workup may be needed based on patient history and physical exam, as well as with cases of primary amenorrhoea. consultation with a physician experienced in reproductive medicine is recommended if menses are not restored after 3 6 months of treatment. bone mineral density the gold standard for evaluation of bone mineral density is with dxa. current recommendations for evaluation with dxa include those athletes with a history of stress fractures, fractures with minimal trauma, a history of hypo-oestrogenism, and disordered eating or eating disorders for a cumulative total of 6 months or more. 64 it is important to remember that in normal female athletes, particularly those in weight-bearing sports, have bone mineral density measurements 12 15% higher than non-athletes. 20 altered bone mineral density may be obvious in the athlete with a stress fracture or fragility fracture. additionally, affected athletes are also more likely to report sprains, strains and other soft-tissue injuries. 65 treatment recommendations prevention and treatment of the triad should employ a multidisciplinary team for best results. the health care team should include a physician, registered dietician and a mental health practitioner, especially for those athletes with eating disorders. additional team members may include athletic trainers, an exercise physiologist, coaches, and parents and other family members. prevention the best way to prevent the detrimental health effects of the triad components is through early recognition of athletes at risk and then incorporation of prompt education and intervention in those athletes. special emphasis should be placed on optimising energy availability and maximising bone mineral accumulation in younger athletes. athletes should be counselled on appropriate nutritional requirements for their age. females of all ages should also be educated on the benefits of regular weight-bearing exercise for bone health. athletes should be screened for menstrual dysfunction and educated on its immediate and long-term health negative health effects. treatment the initial focus of treatment should be on modifying diet and exercise behaviour to increase energy availability. this may be accomplished by increasing energy intake, decreasing energy expenditure, or a combination of both. the aim is to restore normal menstrual cycling and prevent a further loss of bone. energy availability should be increased to at least 30 kcal.kg -1 lean body mass per day, but increasing levels of energy availability over 45 kcal.kg -1 lean body mass per day may be necessary to increase bone mineral density. 45 it is important to ensure that adequate intake of the bone-building nutrients calcium (1 000 1 300 mg.d -1 ), vitamin d (400 800 iu.d -1 ) and vitamin k (60 90 μg.d -1 ) is maintained. 66,67 athletes in intense training also require greater protein intake than for the general population (1.2 1.6 g.kg -1 d -1 ). 68 affected athletes without clinical eating disorders should be referred to a dietician for nutritional counselling. those athletes with clinical eating disorders require consultation with other care providers, as well as individual psychotherapy, cognitive behavioural, group and family therapy. increased energy availability continues until the resumption of menses and is maintained during training and competition. athletes need to maintain minimum criteria to continue with training and competition. close follow-up and open communication with the entire health care team is essential. athletes who fail to maintain appropriate levels of energy availability, refuse treatment, or fail to improve eating behaviour should be withheld from training and competition to focus on their health. in some athletes the addition of pharmacological therapy is beneficial in the treatment of triad disorders. athletes with low energy availability secondary to clinical eating disorders may benefit from antidepressant medications. antidepressants are also used in athletes with concomitant depression and anxiety disorders. 69 the other established and recommended pharmacological treatments in athletes with the triad are aimed at maintenance and restoration of bone mineral density. in females with functional hypothalamic amenorrhoea, hormonal therapy, commonly oral contraceptive pills (ocp) are used to protect bone mineral density. when ocp are used to restore regular menstrual cycles, it will not normalise metabolic factors that impair bone formation, health and performance. therefore it is unlikely to fully reverse low bone mineral density in this population, and studies have shown inconsistent osteogenic effects with ocp. 70,71 current indications for the initiation of treatment with ocp are females older than age 16 years with declining bone mineral density and persistent functional hypothalamic amenorrhoea despite adequate energy availability, with the goal of minimising further bone loss. 70 agents for increasing bone mineral density, such as bisphosphonates and selective oestrogen receptor modulators, are not recommended for use in premenopausal women. 71 bisphosphonates have not been proven effective in women of childbearing age. 72 additionally, they may be stored in the bone for many years, raising concern for possible harm to a fetus during pregnancy. 73 further research into the use of any currently available or novel forms of hormone therapy will be important in increasing bone mineral density in athletes with functional amenorrhoea. summary low energy availability, menstrual function and altered bone mineral density, in isolation or in combination, continue to pose significant health risks to female athletes. we continue to see progress in determining the aetiology, pathophysiology, recognition, diagnosis and management of the triad disorders. all those who work with female athletes should remain vigilant in the education, recognition and treatment of athletes at risk. continued advancement of research efforts and knowledge of the triad disorders aiding in the development of prevention and treatment strategies will allow all women to continue to enjoy the benefits of regular exercise and physical activity throughout their lives. declarations the manuscript has been read and approved by all listed co-authors, and meets requirements of co-authorship. this manuscript has not previously been published. there are no conflicts of interest for any of the authors. there are no other disclosures for the authors. sajsm vol 23 no. 2 2011 55 references 1. nattiv a, agostini r, drinkwater b, yeager kk. the female athlete triad. the inter-relatedness of disordered eating, amenorrhea, and osteoporosis. clin sports med 1994;13(2):405-418. 2. otis cl, drinkwater b, johnson m, loucks a, wilmore j. american college of sports medicine position stand. the female athlete triad. med sci sports exerc 1997;29(5):i-ix. 3. beals ka, meyer nl. female athlete triad update. clin sports med 2007;26(1):69-89. 4. nattiv a, loucks ab, manore mm, sanborn cf, sundgot-borgen j, warren mp. american college of sports medicine position stand. the female athlete triad. med sci sports exerc 2007;39(10):1867-1882. 5. american 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female athlete. philadelphia: saunders, 2002:242-243. 63. identifying and treating eating disorders. pediatrics. 2003;111(1):204-211. 64. khan aa, hanley da, bilezikian jp, et al. standards for performing dxa in individuals with secondary causes of osteoporosis. j clin densitom 2006;9(1):47-57. 65. beals ka, manore mm. disorders of the female athlete triad among collegiate athletes. int j sport nutr exerc metab 2002;12(3):281-293. 66. bergman c, gray-scott d, chen jj, meacham s. what is next for the dietary reference intakes for bone metabolism related nutrients beyond calcium: phosphorus, magnesium, vitamin d, and fluoride? crit rev food sci nutr 2009;49(2):136-144. 67. greer fr, krebs nf. optimizing bone health and calcium intakes of infants, children, and adolescents. pediatrics 2006;117(2):578-585. 68. trumbo p, schlicker s, yates aa, poos m. dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein and amino acids. j am diet assoc 2002;102(11):1621-1630. 69. american psychiatric association. treatment of patients with eating disorders, third edition. am j psychiatry 2006;163(7 suppl):4-54. 70. cumming dc, cumming ce. estrogen replacement therapy and female athletes: current issues. sports med 2001;31(15):1025-1031. 71. liu sl, lebrun cm. effect of oral contraceptives and hormone replacement therapy on bone mineral density in premenopausal and perimenopausal women: a systematic review. br j sports med 2006;40(1):11-24. 72. miller kk, klibanski a. clinical review 106: amenorrheic bone loss. j clin endocrinol metab 1999;84(6):1775-1783. 73. patlas n, golomb g, yaffe p, pinto t, breuer e, ornoy a. transplacental effects of bisphosphonates on fetal skeletal ossification and mineralization in rats. teratology 1999;60(2):68-73. 56 sajsm vol 23 no. 2 2011 i had a thought-provoking moment while listening to a podcast (cyclingsnews.com, 26 march 2009). david millar, the 32-year-old 2007 british national cycling road-racing champion, was interviewed about his accident in the last stage of the 2009 paris-nice race a few weeks earlier during which he crashed and broke his collarbone. not that breaking a collarbone was particularly unusual, as this is the second most common injury sustained by cyclists crashing in pelotons – skin lacerations are the most common under such circumstances. what i found unusual was the manner in which millar discussed the management of the injury. he spoke with confidence about his injury and how it differed from the collarbone injury of lance armstrong. he explained how he had consulted at least 10 specialists for an opinion on how to best treat the injury so that he would be ready to ride in the tour de france starting on 4 july. after obtaining 5 different opinions he settled for the ‘tight rope’ procedure and recruited a specialist in sheffield, uk, who had done 50 such operations in 2008. although this procedure requires 4 weeks of immobilisation, millar chose this method over the other methods that had a quicker recovery time but poorer long-term prognoses. the point to this detailed explanation is that it heralds a new era in sports medicine where specialist practitioners are held accountable and their records and experience carefully examined before a decision is made about utilising their services. this scenario has intriguing consequences, particularly in team sports where there is usually one doctor who serves the whole team, and a coach who may put subtle, or not so subtle, pressure on the doctor to accelerate the treatment of the injured player. sooner, rather than later, an incident involving a high-profile injured player will be the catalyst for the credentials of the doctor managing the case to be exposed. it does not take much insight to see that a sharp legal brain will have a field day with this, particularly if the skills of the doctor or other support staff do not meet the highest standards. on the point of standards, this edition of sajsm includes the latest consensus on the management of concussion injuries. the document represents the consensus view of scientists and practitioners who attended the meeting in zurich in november 2008. this is an important document and therefore we have taken the unusual step of publishing it in sajsm, free of copyright restriction, even though it will also be published in 10 other journals around the world (american journal of sports medicine, journal of science and medicine in sport, journal of athletic training, physical medicine and rehabilitation, journal of clinical neuroscience, scandinavian journal of science and medicine in sport, physician and sports medicine, british journal of sports medicine, clinical journal of sports medicine, journal of clinical sports medicine (japanese journal) and neurosurgery. as explained in the preamble to the document (page 36), it has been developed for the use of physicians, therapists, certified athletic trainers, health professionals, coaches and others involved in the care of injured athletes, whether at the recreational, elite or professional level. this approach of preparing consensus documents for managing an injury/condition within sports medicine is gathering momentum. perhaps it is time to do a stock take of all the controversial management practices in sports medicine and systematically prepare consensus documents on management, with input from the best practitioners in the world. this certainly will lower the risk of a disgruntled athlete instigating legal charges against any medical service provider for not using best practice medicine. mike lambert editor-in-chief athlete/doctor relationship – is the knowledge base shifting? a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial 34 sajsm vol 21 no. 2 2009 sajsm 595 (commentarty).indd commentary 1 sajsm vol. 30 no. 1 2018 neurologist at ringside to be or not to be? n k sethi, md department of neurology, new york presbyterian hospital, weill cornell medical center, new york, usa corresponding author: n k sethi (sethinitinmd@hotmail.com) the risks for both acute and chronic traumatic brain injury are high in contact sports such as professional boxing and mixed martial arts (mma). acute neurological injuries, such as subdural haematoma (sdh), epidural haematoma (edh), subarachnoid haemorrhage (sah), intracranial haemorrhage (ich), diffuse brain contusions without associated haemorrhages, diffuse axonal injuries (dai) and dissection of the vertebral artery/carotid artery, are major causes of boxingrelated mortality and morbidity. the burden of chronic neurological injuries in boxing and mma, like chronic traumatic encephalopathy (cte), dementia pugilistica, chronic post-concussion syndrome, chronic neurocognitive impairment, post-traumatic dementia, post-traumatic cognitive impairment, post-traumatic parkinsonism and persistent posttraumatic headache, is likely much higher but hidden as most injuries express themselves after the combat sports athlete has long retired. ethical issues and position statements of various medical associations ethical issues related to combat sports have been debated vigorously in the medical literature. boxing and mma are invariably thought to be harmful for the brain by the medical community. various medical associations have recommended in their position statements to ban boxing altogether. the american medical association (ama) recommended that until boxing is banned, head blows should be prohibited from the sport [1]. the american academy of pediatrics (1997) opposes boxing as a sport for any child, adolescent, or young adult. the australian medical association (ama) (1997. reaffirmed 2007) [3] stated: ‘all forms of boxing are a public demonstration of interpersonal violence which is unique among sporting activities. victory is obtained by inflicting on the opponent such a measure of physical injury that the opponent is unable to continue, or which at least can be seen to be significantly greater than is received in return’. the ama opposes all forms of boxing and recommends the prohibition of all forms of boxing for people younger than 18 years. the ama further recommended to the international olympic committee and the australian commonwealth games association that boxing be banned from both the olympic and commonwealth games and that media coverage of boxing should be subject to control codes similar to those which apply to television screening of violence. british medical association (bma) opposes amateur and professional boxing; and called for complete ban on boxing; recommending banning boxing for those younger than 16 years old. [4] the canadian medical association (cma) recommended that all boxing be banned in canada. [5] the world medical association (wma) recommended that boxing be banned. [6] the american academy of neurology (aan) in its position statement on sports states that where injuries result in intentional trauma to the brain (for example, from boxing, mma, and extreme fighting), these sports are a serious threat to the neurologic function of those who engage in them and makes the following recommendations: [7] 1. be regulated to reduce the occurrence of permanent brain damage by reduction in the number of direct blows to the head. 2. have a programme to provide participants in these sports: *required formal neurologic examinations, including brain imaging, at regular intervals for all participants who have been knocked unconscious. *additional testing be recommended and monitored by a neurologist who is designated by the state athletic commission. dr hauser in his article titled “beaten into action: a perspective on blood sports” makes a passionate plea to the neurology community to ban boxing, stating: ‘the medical, and especially the neurology, community has an obligation to do more. we need to spread the word that brain bashing is not a socially acceptable spectator sport, and partner with our national organizations to expand and improve the effectiveness of public awareness and other educational initiatives. we should forcefully counter articles in the medical literature taking the position that closer medical supervision could obviate the need for a ban, or even worse that consenting adults have the ethical right to maim each other if they choose to do so. finally, we should avoid the temptation background: ringside physicians are entrusted with the task of protecting the health and safety of combat sports (boxing and mixed martial arts (mma)) athletes. ringside physicians come from various disciplines of medicine such as, primary care, internal medicine, orthopaedics, sports medicine, and otolaryngology. however, there are few neurologists who work as ringside physicians. discussion: boxing and mma are highly controversial sports for a neurologist’ involvement because every punch and kick to the head is thrown with the intention of winning by knocking the opponent out, or resulting in a concussion. thus many neurologists feel it is unethical to support boxing as a ringside physician. conclusion: boxing and mma are universally thought to be harmful to the brain, and nearly all medical associations have made calls to ban boxing and mma. while medical associations and physicians, including neurologists, may not support boxing or mma, their presence at the ringside or cageside helps to make these sports safer through protecting the health and safety of a combat sports athlete. keywords: boxing, mma, traumatic brain injury, chronic traumatic encephalopathy, physician s afr j sports med 2018;30: 1-2. doi: 10.17159/2078-516x/2018/v30i1a4255 http://dx.doi.org/10.17159/2078-516x/2018/v30i1a4255 commentary sajsm vol. 30 no. 1 2018 2 to align with groups whose purpose is anathema to our mission, no matter how great our financial need’. [8] the arguments of dr hauser and others who share his viewpoint have been countered in the medical literature by a few “brave” authors who then risk been labelled either as mavericks or “fans of the sport”. [9,10] over the years, it has also been vigorously debated in the boxing and scientific communities as to whether the sports of boxing and now mma can be made safer. suggestions included restricting the number of shots to the head (this will mandate changes in the rules of the sports), reducing the number of rounds per fight, making headgear mandatory for both amateur and professional fighters, restricting the number of fights per year per fighter, better designed mouthpieces, and by instituting longer periods of mandatory suspension between fights. those on the other side of the fence have countered that these sports cannot be made safer, that no amount of boxing is good for the brain (4 rounds vs. 12 rounds per fight, 4 fights vs. 40 fights in a boxer’s professional career), and that one punch can change everything – it may even kill. the neurologist at ringside is the presence of a neurologist ringside or cageside synonymous with him or her supporting or in any way promoting these sports? military doctors (army physicians), for example, work in the battlefield saving the lives of soldiers and sometimes even of the enemy. however, their role in the frontlines does not mean that they personally support the war or feel that war is good and justified. there is no doubt that by bringing in their critical life-saving skills, their presence saves precious lives in battlefields across the globe. in much the same way, the presence of a neurologist at the ringside or cageside does not imply that he/she supports boxing or thinks that boxing is good for the brain. neurologists too bring their unique life-saving skills to the ringside/cageside. brain imaging, either computed tomography (ct) or magnetic resonance imaging (mri), is currently included in the process of registering for a license to fight in combat sports. however, the imaging requirements for licensure vary among different athletic commissions. some state commissions in the united states require an mri brain scan every three years, others only once, at the time of licensure. some do not require any imaging before licensure.[11] brain imaging, particularly a ct scan of the head, is currently the imaging modality of choice to rule out acute traumatic brain injury after a bout of boxing. there are no guidelines regarding the imaging for chronic traumatic brain injury and chronic traumatic encephalopathy as a result of a fight injury. reviewing these scans and determining brain fitness to fight is a task best suited to a neurologist. assessing for concussion and traumatic brain injury during the course of a fight is no easy task. the signs and symptoms are often subtle. a headache is not usually reported by a fighter. memory and dysarthria are difficult to assess ringside in the one minute rest period between rounds. assessing the fighter’s balance (by the way he walks back to his corner), the presence of a confused state (the fighter walks to the wrong corner after the bell), the presence of irritability (the fighter lashes out at the referee, corner, or inspector) is best gauged by a neurologist by virtue of his training. determining brain fitness after a fight is also best undertaken by a neurologist. management should be on a caseto-case basis, with some combatants meriting discharge from the venue after a neurological evaluation and medical clearance by the physician. others merit transport to the nearest level 1 trauma centre for a ct head scan and further care as deemed necessary. conclusion in some us states and in other countries around the world, the referee and the ringside physician are the sole arbiters of a fight and the only individuals authorised to enter the fighting area at any time during the competition and to stop a fight. for the reasons highlighted above, some commissions, such as the new york state athletic commission (nysac) have mandated that the chief medical officer be a trained neurologist or a neurosurgeon. this author would like to propose that these specialists at the ringside or cageside contribute to making these sports safer. author contributions: nks conceived, drafted and revised the manuscript. study funding: no targeted funding reported. disclosure: nks serves as associate editor, the eastern journal of medicine and as chief medical officer of the new york state athletic commission (nysac). the views expressed are his and do not represent the views of the nysac. references 1. american medical association.h-470.963:boxing injuries. available at: https://ssl3.ama-assn.org/ apps/ecomm/ policyfinderform.pl?sitewww. ama-assn.org&uri/ama1/pub/ upload/mm/ policyfinder/policyfiles/hne/h-470.963.htm. (last accessed on 1 nov, 2017). 2. american academy of pediatrics, council on sports medicine and fitness, et al. policy statement— boxing participation by children and adolescents. pediatrics 2011;128:617-623. [doi: 10.1542/peds.2011-1165] 3. australian medical association. ama position statement on boxing https://ama.com.au/sites/default/files/documents/ama_position_ statement_on_boxing_1997._reaffirmed_2007.pdf (last accessed on 1 nov, 2017) 4. british medical association. boxing: the bma’s position. available at: www.bma.org. uk/health_promotion_ethics/sports_exercise/ boxingpu.jsp. (last accessed on 1 nov,2017) 5. canadian medical association, office for public health. boxing. available at: www. cma.ca/index.cfm/ci_id/3385/la_id/1.htm. (last accessed on 1 nov, 2017) 6. world medical association. wma statement on boxing. available at: www.wma.net/en/ 30publications/10policies/b6/index.html. accessed 1 september, 2010. 7. american academy of neurology position statement on sports that include intentional trauma to the brain. https://www.aan.com/uploadedfiles/website_library_assets/do cuments/6.public_policy/1.stay_informed/2.position_statements/ 3.pdfs_of_all_position_statements/trauma.pdf. (last accessed on 1 nov 1,2017) 8. hauser sl. beaten into action: a perspective on blood sports. ann neurol 2012;72:a4-5. [doi: 10.1002/ana.23743] 9. sethi nk. boxing can be made safer. ann neurol 2013;73:147. [doi: 10.1002/ana.23807] 10. hauser sl. reply to dr sethi. ann neurol 2013;73:147. [doi: 10.1002/ana.23806] 11. sethi nk. neuroimaging in contact sports: determining brain fitness before and after a bout. s afr j sports med 2017;29:1-4. [dx.doi: 10.17159/2078-516x/2017/v29i0a2390] https://www.ncbi.nlm.nih.gov/pubmed/?term=american%20academy%20of%20pediatrics%2c%20council%20on%20sports%20medicine%20and%20fitness%5bcorporate%20author%5d https://www.ncbi.nlm.nih.gov/pubmed/?term=american%20academy%20of%20pediatrics%2c%20council%20on%20sports%20medicine%20and%20fitness%5bcorporate%20author%5d https://www.ncbi.nlm.nih.gov/pubmed/?term=policy+statement%e2%80%94boxing+participation+by+children+and+adolescents https://ama.com.au/sites/default/files/documents/ama_position_statement_on_boxing_1997._reaffirmed_2007.pdf https://ama.com.au/sites/default/files/documents/ama_position_statement_on_boxing_1997._reaffirmed_2007.pdf https://www.aan.com/uploadedfiles/website_library_assets/documents/6.public_policy/1.stay_informed/2.position_statements/3.pdfs_of_all_position_statements/trauma.pdf https://www.aan.com/uploadedfiles/website_library_assets/documents/6.public_policy/1.stay_informed/2.position_statements/3.pdfs_of_all_position_statements/trauma.pdf https://www.aan.com/uploadedfiles/website_library_assets/documents/6.public_policy/1.stay_informed/2.position_statements/3.pdfs_of_all_position_statements/trauma.pdf https://www.ncbi.nlm.nih.gov/pubmed/23034920 https://www.ncbi.nlm.nih.gov/pubmed/?term=sethi%20nk%5bauthor%5d&cauthor=true&cauthor_uid=23378329 https://www.ncbi.nlm.nih.gov/pubmed/?term=sethi+boxing+can+be+made+safer https://www.ncbi.nlm.nih.gov/pubmed/?term=hauser%20sl%5bauthor%5d&cauthor=true&cauthor_uid=23378330 https://www.ncbi.nlm.nih.gov/pubmed/23378330 original research 26 sajsm vol. 26 no. 1 2014 background. rugby is a highly demanding sport that carries a high risk of injury, specifically to the neck region. repetitive loading of the neck during the scrum or tackle phase may increase neck symptoms and pain. objectives. the objective of this cross-sectional, descriptive study was to determine the prevalence of self-reported neck pain in rugby union players in gauteng province, south africa. methods. one hundred rugby union players of a mean ± standard deviation age of 22.1±2.4 years, height 1.84±0.07 m and weight 95.3±15.2 kg, completed the four-part questionnaire. results. we found a 12% prevalence of current neck pain, and 52% of the players reported experiencing previous neck pain. neck pain was more frequently reported in forwards, with the tackle being the most commonly stated cause. eighteen players reported mild to moderate disability as a result of neck pain. the players reported that neck strengthening, on-field treatment and coaching could be improved to prevent neck pain. conclusion. current and previous neck pain is prevalent in rugby union players. neck pain may be a sign of underlying pathology; therefore, players presenting with chronic or acute neck pain should be assessed thoroughly by a sports physician. neck conditioning and strengthening should be encouraged in all players to prevent the deleterious effects that rugby union may have on the cervical spine. s afr j sm 2014;26(1):26-30. doi:10.7196/sajsm.512 the prevalence of self-reported neck pain in rugby union players in gauteng province e d watson, msportsc, hons (biokinetics); r-l hodge, bhsc (hons) (biokinetics); m gekis, bhsc (hons) (biokinetics) centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: e d watson (estelle.watson@wits.ac.za) rugby is a highly demanding, full-contact sport that carries a high risk of injury. furthermore, the fre quency and burden of these injuries appears to have increased with the professionalism of the sport; e.g. the inci dence of in jury has been estimated to have increased from 47/1 000 player hours before professionalism to 74/1 000 player hours after professionalism.[1] other studies have suggested an even higher incidence of injury of 91 97/1 000 player hours.[2] new, previous and recurrent injuries all play a big role in lost playing hours.[2] the most common types of injuries are sprains, strains and contusions. [1,2] the most commonly injured region is the lower limbs,[2] while the prevalence of injuries to the head and neck is estimated at 29 34%.[1] the cervical spine is at particular risk of injury due to its biomechanical design. unsurprisingly, cervical trauma seems to be a particular risk during the scrum and tackle phase in rugby union.[3] predictably, forwards have a disproportionally higher risk of cervical injury due to the forces transmitted during scrummaging.[3] although not the most common, injuries to the neck may often be the most catastrophic. a study by noakes et al.[4] found that five schoolboy rugby union players in south africa (sa) died from spinal cord injuries, while an even higher portion had resultant tetraplegia. there is also increasing awareness of the high amount of ‘near miss’ injuries – severe injuries to the cervical spine that do not affect the spinal cord.[5] changes to the rules have brought about a reduction in the incidence of spinal cord injuries;[4,5] however, the incidence of cervical injuries is still high. in a prospective study of spinal injuries over two seasons, fuller et al.[6] found no catastrophic injuries; however, three players sustained career-ending injuries. minor or non-catastrophic injury to the cervical spine is common, with the incidence ranging from 0.26 9.17/1 000 player hours.[7] in amateur rugby union players, 69% of neck injuries are minor, 17% mild and 7% moderate to severe. [8] these injuries may result in neck symptoms,[9] reduced playing time, and associated healthcare costs. furthermore, the cumulative consequences of these injuries have resulted in premature and advanced degenerative changes in the cervical spine in rugby union players.[10] in a study by hogan et al.,[11] front-row rugby union players presented with asymptomatic, yet significant degenerative changes of the disc spaces and apophyseal joints. castinel et al.,[12] using static magnetic resonance imaging (mri), found that over half of the rugby union players in their cohort presented with abnormalities of the cervical spine. furthermore, changes in the active range of motion have also been documented.[13] therefore, neck pain is theorised to be prevalent in rugby union players, especially forwards. indeed, gemmell et al.[9] found an 83% prevalence of neck pain in forwards compared with a 41% prevalence in back-row players. there is much research on incidence of injuries; however, very little research has been done on the prevalence of selfreported neck pain in rugby union players in sa. mailto:estelle.watson@wits.ac.za sajsm vol. 26 no. 1 2014 27 methods a cross-sectional, descriptive survey was conducted to determine the prevalence of neck pain in rugby union players in gauteng province. a four-part questionnaire (available in the online supple mentary material – appendix a) was adapted from the international rugby board’s (irb’s) injury assessment form[14] and included the neck disability index (ndi).[15] a convenience sample was used and recruitment took place at university rugby union clubs and professional clubs in johannesburg and pretoria. players, aged 18 35 years, who were registered with a rugby union club were included in the study. one hundred players from different levels participated in the study. level of play ranged from professional (n=23), to university first (n=17) and second teams (n=9), with the majority playing for a university residence team (n=51). players were approached during training sessions, and provided with an information sheet. all participants signed an informed consent form prior to filling out the questionnaire. the study was approved by the human research ethics committee (hrec) of the university of the witwatersrand (reference m120401). results demographic data one hundred male rugby union players partici pated in the study; 41 played in the backline and 59 were forwards. the selfreported demographic data for the group are shown in table 1. mean height and weight were found to be statistically significantly higher in the forward than in the back players. a comparison of the height, weight and age between the professional and amateur players is shown in table 2. the professional players showed statistically significantly higher values for height and weight and were significantly older than the amateur players. neck pain when asked whether they had ever been injured due to rugby union, 91% of the players responded ‘yes’, 5% responded ‘no’ and 4% did not comment. twelve per cent of the players reported that they were currently experiencing neck pain, and 52% reported experiencing previous neck pain. all players currently experiencing neck pain were amateurs, and 7 players (14%) that had previous neck pain played professionally. nine of the 12 players (75%) who were currently experien cing neck pain were forwards, while 34 out of the 52 players (65%) reporting previous neck pain were also forwards. players who had experienced neck pain (n=52) were asked to select a cause of the pain from a list of options, with rugby union reported as the leading cause (n=43) (fig. 1). the players who stated that rugby union was the cause of injury (n=43) were then asked to select the position played at the time of injury. the position associated with the highest occurrence of injury was the loose head prop, with ten players (23%) having been injured while playing in this position. seven players (16%) stated that they played tight head prop, and 6 players were playing hooker (14%). the tight head flank position accounted for 12% of injuries, and inside centre and lock accounting for 9% and 7% of injuries, respectively. the backline position with the highest occurrence of neck injuries was the flyhalf (7%). the players were then asked whether they were playing in their normal position at the time of injury: 89% stated that they were, while 9% stated that they were not, and 2% did not provide comment. furthermore, players were asked to select the situation where the injury occurred: the majority (n=40) were injured during a match situation, while a small percentage were injured during a full contact skills training session (n=2), and during warm-up or ‘other’ (n=1, respectively). fig. 2 shows that the main cause of rugby unionrelated neck injury was the tackle (n=25), followed by the scrum (n=22) and collisions (n=11). players with neck pain (n=52) were asked to select the course of treatment under taken: the majority were treated by a physiotherapist (62%), followed by a doctor (48%) and a biokineticist (10%). a further 10% reported receiving no treatment for their neck pain. furthermore, these players were asked to state the outcome of the treatment: 64% had a full recovery, 15% stated having a partial recovery, 2% had not recovered and 4% indicated that they were currently injured. eight players (15%) gave no comment. these players were also asked whether they felt cautious when doing certain activities after their neck pain or injury. thirty-four players (65%) indicated that they were cautious, 23% responded in the negative, and 12% gave no comment. the same question was repeated regarding how cautious they were with returning to full-contact rugby union: 44% answered in the affirmative and the same number stated that they were not cautious; six players (12%) gave no comment. the players were also asked to select from a list the length table 1. demographic data of rugby union players all (n=100) mean±sd backs (n=41) mean±sd forwards (n=59) mean±sd p-value height (m) 1.84±0.07† 1.81±0.07 1.86±0.07* 0.001 weight (kg) 95.30±15.30‡ 84.43±9.60 102.65±13.96* 0.000 age (years) 22.10±2.40 21.88±1.99 22.29±2.67 0.063 sd = standard deviation. * statistically significant difference (p<0.05). † missing data (n=3). ‡ missing data (n=2). table 2. demographic differences between professional and amateur players professional players (n=23) mean±sd amateur players (n=76) mean±sd p-value height (m) 1.87±0.06* 1.83±0.07† 0.011 weight (kg) 105±11.14* 92.35±15.17 0.000 age (years) 24±3* 22±2 0.000 * statistically significant difference (p<0.05). † missing data (n=2). 28 sajsm vol. 26 no. 1 2014 of time taken to return to normal level of play. the majority of players took one month to return to play (fig. 3). preventive measures all players (n=100) were asked whether they felt that there were enough preventive measures to reduce the risk of neck pain during rugby union: 44% felt that there were not enough measures in place, 55% said that there were enough measures in place, and 1% provided no answer. the players who felt that there were not enough measures in place were then prompted to select from a list the factors that needed to be improved. players were able to select more than one option. the majority felt that neck strengthening was a factor that could be improved upon, as well as on-field treatment and coaching (fig. 4). neck strengthening players were asked whether neck strengthen ing formed part of their training programme, and if so, how many times a week they performed such training: 56 responded affirmatively, while 43 responded in the negative and one player gave no comment. most players who answered affirmatively stated that they performed these exercises 1 2 times per week (fig. 5). ndi thirty-one players (60%) filled out the ndi, and were classified into disability categories according to vernon.[15] the mean±sd ndi score, out of a possible 50, was 6.7±4.7, with the highest score being 23 (n=2). the rugby union players were classified as having no disability (n=13), mild disability (n=15) or moderate disability (n=3). the ndi is comprised of 10 categories of daily activities/areas that could be affected by neck pain. to ascertain which area caused the most concern, the total sum of scores was added up for each category (fig. 6). pain and headaches were most commonly reported, as well as lifting, reading and sleeping. discussion it is well known that the incidence of neck injuries in rugby union is high, reported to account for 2 14% of all injuries.[7] common injuries incurred include cervical facet joint sprain, neck muscle strain and neuropathy.[8] rugby car accident other fall other sport unknown77% 11% 5% 3% 2% 2% cause of neck pain fig. 1. cause of neck pain. 58 51 26 21 12 7 70 60 50 40 30 20 10 0 tackle scrum collision rucked cleaned headbutt causes p la ye rs . % fig. 2. cause of rugby-related neck injury. 12 25 37 14 0 2 12 40 35 30 25 20 15 10 5 0 p la ye rs , % length of time to return to sport im m ed ia te ly 1 w ee k 1 m o n th 6 m o n th s 1 ye ar m o re t h an 1 y ea r n o c o m m en t fig. 3. length of time taken to return to sport following a neck injury. sajsm vol. 26 no. 1 2014 29 many studies have addressed the incidence and severity of neck injuries in rugby union,[7,8] but few have addressed the potential lasting effects, or prevalence of neck pain in these players. it is also common for rugby union to cause pathological changes to the cervical spine; but these changes do not always manifest clinically. [11] in addition, repetitive microtrauma from collisions in the scrum has also been associated with insidious, chronic neck pain.[10] therefore, we undertook this study to determine the prevalence of neck pain in rugby union players in gauteng province, sa. our study indicated a 12% prevalence of neck pain in rugby union players, with over half of the players having experienced neck pain in the past. similar to a study by gemmell and dunford,[9] our study found a higher prevalence of neck pain in forwards than in backline players. this comes as no surprise, due to the intense repetitive forces on the spine during scrummaging.[16] in addition to the scrum, the tackle appears to be the phase of play where most injuries occur. [17] in the current study, the majority of the rugby-union-related neck injuries reportedly occurred during a tackle, which has been the phase of play found to be the most associated with spinal injuries.[18] a large portion of players in our study felt that there were not enough preventive measures to reduce the risk of neck pain. the main preventive measure suggested by the players was neck conditioning. strengthening of the neck muscles is an encouraged preventive measure for both injury frequency and severity.[19] although proper condition of the neck muscles is a practical method of injury prevention, almost half of the players in the current study reported performing no neck strengthening. du toit et al.[20] found that neck strength was not adequate to meet the unique positional requirements needed in rugby union; this remains an area in training that still requires improvement. what is more, experienced coaches and knowledge able medical personnel can aid in making rugby union safer.[19] similar to the study by shelly et al.,[18] our players reported both on-field treatment and coaching as major contributing factors that can be improved upon. to this effect, sa has implemented the boksmart programme, training 38  500 coaches and referees on rugby union safety. [21] the programme aims to educate coaches, 0 5 10 15 20 25 30 35 sum of scores driving work personal care recreation concentration sleeping reading lifting headaches pain intensity 11 11 13 16 17 25 25 29 30 31 fig. 6. total score for each disability category. 16% 2% 5% 77% days per week no comment 1 2 3 4 ≥5 fig. 5. frequency of neck strengthening per week. p la ye rs , % 40 35 30 25 20 15 10 5 0 10 1212 1617 24 28 35 n ec k co n d it io n in g o n -� el d r x c o ac h in g pr esc re en in g r ef er ee ru le s o f g am e m an ag em en t su rf ac e preventive measure fig. 4. players’ opinions on factors that could prevent neck injuries. (rx = treatment.) 30 sajsm vol. 26 no. 1 2014 referees and first-aiders on safe rugby union practices, and provide support and educational resources. furthermore, coaches are equipped to teach correct tackling technique, which may be instrumental in reducing injury risk.[21] however, the question remains whether the players believe this is sufficient, and whether these learned practices are being applied on field.[22] it has been suggested that participation in rugby union can affect the range of movement (rom) of the neck, leading to mild or moderate disa bility.[9] in fact, active rom in rugby union players has been found to be similar to that of whiplash patients.[23] indeed, in the current study, 18% of players reported mild to moderate disability from their neck pain, and reported issues such as pain, headaches, and difficulty lifting, reading and sleeping. even more worrisome is that many studies have radiologically shown degenerative changes in the neck that do not manifest clinically.[11] therefore, the prevalence of neck pain may not tell the full story of underlying cervical abnormalities. furthermore, minor injuries and neck pain may be a signpost for more serious neck pathology, and should be assessed accordingly.[10] study limitations due to the descriptive nature of the study, it is not possible to infer the actual cause of the neck pain reported. furthermore, the study is limited by the involved interpretation of the term ‘injury’ by the player. further studies should include a clinician-diagnosed neck injury to minimise potential bias due to the ambiguity of these concepts. although our study described self-reported neck pain prevalence in a small number of rugby union players playing for specific clubs within gauteng province, it revealed an interesting observation that warrants further investigation on a larger scale. conclusion this study provides interesting insight into neck pain prevalence in rugby union players in gauteng province. the prevalence of current and previous neck pain in this population is high, with neck pain being more prevalent in forwards than backline players. neck pain caused mild to moderate disability in 18% of the players. neck conditioning and strengthening should be encouraged in all players, to prevent to the deleterious effects that rugby union may have on the spine. in addition, players presenting with chronic or acute neck pain should be assessed thoroughly by a sports physician. acknowledgements. we thank all the rugby union players who took the time to participate in the research. references 1. bathgate a, best jp, craig g, jamieson m. a prospective study of injuries to elite australian rugby union players. br j sports med 2002;36(4):265-269. [http://dx.doi. org/10.1136/bjsm.36.4.265] 2. brooks j, fuller cw, kemp s, reddin db. epidemiology of injuries in english professional rugby union: part 1 match injuries. br j sports med 2005;39(10):757766. [http://dx.doi.org/10.1136/bjsm.2005.018135] 3. quarrie kl, cantu rc, chalmers dj. rugby union injuries to the cervical spine and spinal cord. sports med 2002;32(10):633-653. [http://dx.doi.org/10.2165/00007256200232100-00003] 4. noakes t, jakoet i, baalbergen e. an apparent reduction in the incidence and severity of spinal cord injuries in schoolboy rugby players in the western cape since 1990. s afr med j 1999;89(5):540. 5. noakes t, jakoet i. spinal cord injuries in r ugby union players. bmj 1995;310(6991):1345-1346. 6. fuller cw, brooks jhm, kemp spt. spinal injuries in professional rugby union: a prospective cohort study. clin j sport med 2007;17(1):10-16. [http://dx.doi. org/10.1097/jsm.0b013e31802e9c28] 7. swain ms, lystad rp, pollard h, bonello r. incidence and severity of neck injury in rugby union: a systematic review. j sci med sport 2011;14(5):383-389. [http:// dx.doi.org/10.1016/j.jsams.2010.10.460] 8. swain ms, pollard hp, bonello r. research incidence, severity, aetiology and type of neck injury in men's amateur rugby union: a prospective cohort study. chiropr osteopat 2010;18(18):3-12. 9. gemmell h, dunford pj. a cross-sectional study of the prevalence of neck pain, decreased cervical range of motion and head repositioning accuracy in forwards and backs in rugby union. clinical chiropractic 2007;10(4):187-194. [http://dx.doi. org/10.1016/j.clch.2007.09.002] 10. o'brien c. "rugby neck": cervical degeneration in two front row rugby union players. clin j sport med 1996;6(1):56-59. 11. hogan b, hogan na, vos, pm, eustace sj, kenny pj. the cervical spine of professional front-row rugby players: correlation between degenerative changes and symptoms. irish journal of medical science 2010;179(2):259-263. [http:// dx.doi.org/10.1007/s11845-009-0432-3] 12. castinel bh, adam p, milburn pd, et al. epidemiolog y of cer vical spine abnormalities in asymptomatic adult professional rugby union players using static and dynamic mri protocols: 2002 to 2006. br j sports med 2010;44(3):194-199. [http://dx.doi.org/10.1136/bjsm.2007.045815] 13. lark sd, mccarthy p. the effects of a rugby playing season on cervical range of motion. j sport sci 2010;28(6):649-655. [http://dx.doi.org/10.1080/02640410600944543] 14. international rugby board (irb). http://www.irbplayerwelfare.com (accessed 1 september 2013). 15. vernon h. the neck disability index: state-of-the-art, 1991 2008. j manipulative physiol ther 2008;31(7):491-502. [http://dx.doi.org/10.1016/j.jmpt.2008.08.006] 16. preatoni e, stokes k, england m, trewartha g. forces generated in rugby union machine scrummaging at various playing levels. women 2012;7771:197-297. 17. garraway w, macleod d. epidemiology of rugby football injuries. lancet 1995;345(8963):1485-1487. [http://dx.doi.org/10.1016/s0140-6736(95)91040-9] 18. shelly m, butler js, walsh mg, o’byrne jm. spinal injuries in irish rugby: a ten-year review. j bone joint surg am 2006;88(6):771-775. [http://dx.doi.org/10.1302/0301620x.88b6.17388] 19. dietzen c, topping b. rugby football. physical medicine and rehabilitation clinics of north america 1999;10(1):159-175. 20. du toit de, olivier p, grenfell l, eksteen b. isokinetic neck strength norms for schoolboy rugby forwards. south african journal of sports medicine 2005;17(1):1926. 21. hendricks s, lambert m. tackling in rugby: coaching strategies for effective technique and injury prevention. int j sports sci coaching 2010;5(1):117-136. [http://dx.doi.org/10.1260/1747-9541.5.1.117] 22. viljoen w, patricios j. boksmart – implementing a national rugby safety programme. br j sports med 2012;46:492-493. [http://dx.doi.org/10.1136/ bjsports-2012-091278] 23. lark sd, mccarthy pw. cervical range of motion and proprioception in rugby players versus non-rugby players. j sports sci 2007;25(8):887-894. [http://dx.doi. org/10.1080/02640410600944543] http://dx.doi.org/10.1136/bjsm.36.4.265] http://dx.doi.org/10.1136/bjsm.36.4.265] http://dx.doi.org/10.1136/bjsm.2005.018135] http://dx.doi.org/10.2165/00007256-200232100-00003] http://dx.doi.org/10.2165/00007256-200232100-00003] http://dx.doi.org/10.1097/jsm.0b013e31802e9c28] http://dx.doi.org/10.1097/jsm.0b013e31802e9c28] http://dx.doi.org/10.1016/j.jsams.2010.10.460] http://dx.doi.org/10.1016/j.jsams.2010.10.460] http://dx.doi.org/10.1016/j.clch.2007.09.002] http://dx.doi.org/10.1016/j.clch.2007.09.002] http://dx.doi.org/10.1007/s11845-009-0432-3] http://dx.doi.org/10.1007/s11845-009-0432-3] http://dx.doi.org/10.1136/bjsm.2007.045815] http://dx.doi.org/10.1080/02640410600944543] http://www.irbplayerwelfare.com http://dx.doi.org/10.1016/j.jmpt.2008.08.006] http://dx.doi.org/10.1016/s0140-6736 http://dx.doi.org/10.1302/0301-620x.88b6.17388] http://dx.doi.org/10.1302/0301-620x.88b6.17388] http://dx.doi.org/10.1260/1747-9541.5.1.117] http://dx.doi.org/10.1136/bjsports-2012-091278] http://dx.doi.org/10.1136/bjsports-2012-091278] http://dx.doi.org/10.1080/02640410600944543] http://dx.doi.org/10.1080/02640410600944543] the discipline of sports medicine has developed exponentially in south africa in the last 25 years. the first major scientific publications were on orthopaedic injuries, dehydration or heat stress. reflecting on how the profession has evolved in content and depth of knowledge is remarkable. in this relatively short time period an enormous amount has been learnt about the aetiology of injury, the accelerated treatment of injury, and the prophylactic role that physical activity plays in reducing the risk of certain diseases. injuries that may once have ended the career of a player can now be surgically repaired, with the player resuming his/her place in the team within the same season. the science of fitness is sufficiently advanced to ensure that, for example, a professional rugby player weighing 100 kg can sprint and tackle almost tirelessly for 80 minutes, an elite ultra-distance runner can run 90 km averaging 3 minutes and 36 seconds a kilometre, and an elite powerlifter can bench press over 400 kg. these are just some examples representing extreme fitness that have been achieved, in part, by the application of science. recovery after competition or a hard training session used to take place in the pub over a couple of beers. nowadays, enhancing recovery after exercise has become a specialist field, with some professional teams employing support staff trained in ‘recovery’. these practitioners have a repertoire of evidence-based protocols that include compression garments, ice-water therapy, massage, and protein drinks. accelerated recovery after matches and training is probably as important to a team as the ability to acquire skills and develop new game plans. failure in any of these facets will lead to a team underperforming. an outsider looking in might form the impression that the application of science and sports medicine to sports performance and injury reduction is ‘all wrapped up, signed and sealed’. what more is there to learn? however, anyone in the business of exercise science or sports medicine will know that the fun and games are just beginning. take for example the recent predicament that jake white, coach of the national rugby team, finds himself in (as we go to press). conventional wisdom has guided the coach in deciding to let his top players miss the overseas leg of the tri-nations tour so that they can recuperate and rejuvenate as they prepare for the remaining 12 weeks before the world cup. science has shown that after a rugby season 96% of the players have at the very least a niggling injury, 50% of the players have more serious injuries, and 1% will require surgery to repair an ongoing injury. the decision of the coach to rest the players can be supported by strong evidence, and therefore surely he cannot be faulted? however, based on the reaction from certain quarters it seems that these ‘evidence-based decisions’ are not universally supported. the sponsors are annoyed because of the perceived lack of publicity, and the fans feel that they are being betrayed because their stars are not playing, and ‘how can they support a team that is not the best?’. added to the antagonistic forces are the mumblings from australia about south africa being in breach of contract because of the ‘under-strength’ team. from the ruckus that the coach’s well-intentioned decision has caused, it is clear that other strategies will have to be adopted in the future to ensure that the high-profile players are always visible, while at the same time being free from injuries and fatigue. this scenario of sports medicine being at odds with popular opinion is just one example suggesting that the field of sports medicine is still facing new challenges which will have to be met with as much vigour and innovation as the challenges that scientists and doctors were faced with 25 years ago. on the topic of innovation, this issue of the journal is filled with a range of studies that reflect the creative work of south african scientists and show how local research contributes to the development of sports science and sports medicine. may you enjoy the read! mike lambert editor-in-chief sports medicine – still evolving? editorial sajsm vol 19 no. 2 2007 29 pg29.indd 29 7/5/07 10:33:10 am sajsm 610.indd 16 sajsm vol. 27 no. 1 2015 original research background. data on the incidence of football injuries and exposure time of players during matches and training in the south african (sa) premier soccer league (psl) are lacking. objective. to calculate the incidence of injuries and the exposure time (practice and match) of the players of a psl team over a full season. methods. injury and training data of the players in the squad (n=32) were recorded on a daily basis by the medical support staff, according to the methods of the football medical assessment and research centre (f-marc) protocol. results. one hundred and thirty injuries were recorded in the season. the most affected body parts were the thigh (n=27, 21%) and ankle (n=27, 21%). the overall incidence was 13.4 injuries per 1 000 player-hours. the incidence during training was 6.6 injuries/1 000 playerhours and during matches 88.9 injuries/1 000 player-hours. the most frequent injury was haematoma/contusion/bruising (n=43, 33%). of the total injuries, 12% were recurrent. injury through contact with another player was high (62%). seventy-six per cent of the injuries were not associated with any violation of the laws of the game. the average time off due to injury was 8 days. the total exposure time over the full season resulted in a combined average of 18 162 minutes (~303 hours). conclusion. these data differ from the data in european studies. injury and exposure data measured throughout the season have the potential to identify risks and mechanisms of injuries. this study highlights the necessity for all clubs in the psl to adopt a standardised injury monitoring programme, using standardised methodology, so that the management of professional players in sa may be improved. s afr j sports med 2015;27(1):16-19. doi:10.7196/sajsm.610 the incidence of injuries and exposure time of professional football club players in the premier soccer league during football season t calligeris,1,3 bsc hons (physio), mphil (sports physio); t burgess,2,3 bsc (physio), phd; m lambert,2 phd 1 sports science physiotherapy centre, sports science institute of south africa, cape town, south africa 2 division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, south africa 3 division of physiotherapy, department of health and rehabilitation sciences, university of cape town, south africa corresponding author: t calligeris (theo@sspc.co.za) football, also known as soccer, is the most widely played sport in the world, with ~240 million people playing regularly in  more than 200 countries. [1] the science of football started emerging in the 1970s; however, there were not many international research papers published during this era. by the 1990s, there were further research developments and more papers published. a review of 20 epidemiological studies on adult soccer players showed that epidemiological information with regard to soccer injuries was inconsistent and incomplete.[1] since the 1990s, more papers have been published, showing how the science of football and medical support structures of teams have evolved. [2,3] this proliferation of knowledge has led to the establishment of the independent research body of the fédération internationale de football association (fifa) called f-marc (football medical assessment and research centre) in 1994, uniting an international group of experts in football medicine. in south africa (sa) the application of scientific knowledge on the description and prevention of injuries in football is lacking at all levels. there are poorly developed support structures, particularly at school and university level, and the growth of applied science of the local game has been lacking. for example, a pubmed search using the term ‘soccer football south africa’ revealed four results, ‘soccer south africa’ revealed 36 results and ‘football south africa’ displayed 54 results, of which the majority were related to rugby football. the articles on football made no mention of the premier soccer league (psl) in sa. this is unfortunate, because research on football in sa is a necessary tool required to answer questions that are specific to the demands of the game in sa. without answering these questions, the rate of improvement in the local game will be curtailed. also, without data on injuries in the psl, it is difficult to determine whether any changes occur after intervention in any aspect of a player’s management. although many studies have been conducted on players in europe, these data may not necessarily apply to players in sa. therefore, the objective of this study was to describe the incidence of injuries and exposure time of players in a professional football club in the psl over a full season, using a standardised method of collecting data.[4] an understanding of injury characteristics in sa football may contribute towards developing injury-prevention strategies and possible rule changes that may also reduce the risk of injury. methods the study had a retrospective cohort design. participants gave their informed consent for their data to be analysed for the study after the nature, purpose and procedures were thoroughly explained. the study was approved by the human research ethics committee of the university of cape town (hrec ref 308/2010). participants included healthy, active male professional footballers who played for a psl 1st team and reserve team (ajax). a player baseline information form was completed by the chief club physiotherapist in consultation with the players. whenever a player in an official club match or practice was sajsm vol. 27 no. 1 2015 17 injured, the details and circumstances about the injury were recorded immediately by the chief club physiotherapist, according to the f-marc injury report form.[4] an injury was defined as any ‘physical complaint sustained by a player that resulted from a football match or football training, irrespective of the need for medical attention or time loss from football activities. an injury that results in a player receiving medical attention is referred to as a ‘medical attention’ injury, and an injury that results in a player being unable to take a full part in future football training or match play as a ‘time loss’ injury.[4] the exposure time was calculated from the total number of hours of participation per day, defined according to the following categories: • normal field training session with the coach and manager • recovery session in the gym comprising spinning, hydro-exercises and stretching • conditioning session • endurance session • high-performance testing session. all injuries during the season were expressed as injuries/1 000 player-hours, as described by brooks and fuller.[5] the data are presented as absolute numbers, percentages, averages (95% confidence intervals (cis)) or means (standard deviations (sds)), as appropriate. results description of players a total of 32 players participated in the study. the average (sd) age of the players was 24 (2) years. average height and weight were 1.8 (0.1) m and 75.6 (4.1) kg, respectively. quantification of exposure type the players spent on average 67% of their time training, 10% playing matches, 13% in recovery training and 9% in conditioning training (table 1). the remainder of the time was spent doing endurance training or testing. there were 236 training sessions over the season. injuries over the whole season, 130 injuries were documented, comprising 15 preseason injuries (12%) and 115 inseason injuries (fig. 1). four injuries did not have a ‘time off ’ value and were excluded from the data on time off from training and competition. the overall injury rate was 13.4/1 000 playerhours (95% ci 11.1 15.7). lower rates were found in training (6.6/1 000 player-hours; 95% ci 4.6 8.6) as opposed to matches (88.9/1 000 player-hours; 95% ci 70.2 107.6). the nature of the injuries varied; however, the most common body parts injured were the thighs (n=27) and the ankles (n=27) (table 2). the average time off for all injuries was 8 days. minor injuries (<7 days) accounted for 18%, moderate injuries (8 28 days) 26% and severe injuries (>28 days) 56% of the injuries. two per cent of the days during the season were lost because of minor injuries, 7% were lost owing to moderate injuries and 23% were lost to severe injuries. sixty-five injuries occurred on the nondominant side and 57 injuries on the dominant side of the body. eight injuries were sustained on other parts of the body (head and spine). the average time off following an injury to the non-dominant side was 10 days table 1. total different exposure times per player over one season total time (min) training match recovery conditioning endurance testing total mean 12 252 1 834 2 324 1 701 39 12 18 162* –95% 10 610 1 457 2 006 1 454 24 9 15 748 95% 13 894 2 211 2 642 1 949 53 15 20 575 *302:42 h:min (95% ci 262:28 342:55). table 2. injuries according to body part* body part n (%) thigh 27 (21) ankle 27 (21) hip/groin 16 (12) lower leg/achilles tendon 15 (12) knee 11 (8) head/face 10 (8) low back/sacrum/pelvis 8 (6) foot/toe 5 (4) sternum/ribs/upper back 3 (2) neck/cervical spine 2 (2) shoulder/clavicle 2 (2) upper arm 2 (2) wrist 1 (1) hand/finger/thumb 1 (1) all groups 130 (100) *data are expressed as a per cent of the total number of injuries. 0 30 60 90 120 150 180 210 240 270 300 330 ankle thigh hip/groin lower leg/achilles knee head and face back/sacrum foot/toe sternum/ribs/ub neck/cervical shoulder/clavicle upper arm wrist hand/�ngers day preseason inseason fig. 1. distribution of the 130 injuries that occurred during preseason (0 47 days) and inseason (48 341 days), showing the body parts that were injured. the body parts are on the right of the figure with the symbol to the left, e.g. hand/fingers is represented by the symbol ×. (ub = upper back.) 18 sajsm vol. 27 no. 1 2015 (95% ci 6 14) and to the dominant side 6 days (95% ci 4 8). the majority of the players were right-foot dominant. the longest average time off occurred with sternum/ribs/upper back injuries (23 days, range 5 38; n=3), followed by thigh injuries (11 days, range 2 79; n=27), hip/groin injuries (11 days, range 1 41; n=14) and ankle injuries (10 days, range 2 57; n=27). the most common type of injury was a haematoma/contusion/bruise, representing 33% of all injuries (table 3). midfielders were most affected by haematoma/contusion/bruise type injuries (n=22), with a mean time off from training and competition of 4 (5) days. they were also more likely to sustain an injury, recurrent or non-recurrent, than any other player position, while goalkeepers sustained the least number of recurrent and nonrecurrent injuries. more injuries were first-time injuries (n=114, 88%), with the remainder being concurrent (n=16, 12%). four players did not return to play owing to the severity of the injury or were transferred to another club; all four sustained non-recurrent injuries. seventy-seven per cent (n=99) of the injuries were a result of trauma, while 23% (n=30) were related to overuse. defenders sustained more overuse injuries (n=13, 30%) than midfielders (n=11, 19%). forwards were more likely to sustain an injury owing to trauma (n=16, 76%) than to overuse (n=5, 24%). more injuries occurred during matches (n=87, 67%) than in training (n=43; 33%) over the full psl season. of the total injuries, midfielders sustained most of the match injuries, followed by defenders, forwards and goalkeepers. the same pattern was seen in training injuries. a total of 43 (33%) non-contact and 87 (67%) contact injuries were recorded over the full season. of all the injuries over the season, 24% (n=31) were as a result of a violation of the laws (table 4). discussion the first finding of this study was that the mean training and match exposure times per player during the season were 12 252 minutes (~204 hours) and 1 834 minutes (~31 hours), respectively. this can be compared with european studies, which have shown that the mean training and match exposure times per player are 15 720 minutes (262 hours) and 2 400 minutes (40 hours), respectively.[6] this suggests that professional european players are exposed to more football per annum than sa players, which has the potential to affect injuries and cumulative improvement in the level of performance during a season. the second finding of this study was that there were 6.6 injuries/ 1 000 player-hours during training and 88.9 injuries/1 000 playerhours during matches. twelve per cent of all injuries were sustained in the preseason phase of training. studies in europe have shown that preseason injuries contribute to 17% of the total number of injuries.[7] it may be argued that preseason injuries are fewer in sa owing to the lower exposure times, but a counterargument to this is that sa players are less prepared for the inseason phase and may therefore be at a greater risk of inseason injuries owing to poor preparation. further research needs to be done to clarify the interpretation. the fact that most injuries occurred at the beginning and end of the season may be owing to lack of match fitness, strength and conditioning early in the season, and the cumulative effect of repeated and prolonged exposure to football at the end of the season. the latter may have been exacerbated by the demand from the psl to complete the league schedule sooner than usual to accommodate the fifa world cup in 2010. the average time off in this study was 8 days, compared with other studies, which describe 17 days[8] and 18 days.[9] this can be interpreted in one of two ways: either the injuries of the european players were more serious, or the medical care and management approach of the club towards the player was different. once again, further research will need to identify the correct interpretation. this has important clinical implications that affect the management of the players. certain body parts have been shown to have a high risk of injury with a high time loss factor, e.g. thigh (n=27), with a maximum time off of 79 days. these findings are consistent with other studies.[10] non-dominant body side injuries (n=65) occurred slightly more frequently than injuries on the dominant side (n=57). other studies have shown contrasting results.[11] in this study, an interesting observation showed that players took a longer time to return to play if an injury was sustained to the non-dominant side of the body as opposed to the dominant side. once again, this has important clinical implications for management. a study of european football showed a significantly higher incidence of overuse injuries in the preseason compared with injuries arising from trauma (68% v. 29%, respectively). the percentage of contact injuries during preseason was significantly less than inseason (29% v. 40%, respectively).[7] the percentage of overuse injuries sustained inseason was also greater than traumatic injuries (56% v. 40%, respectively).[7] however, different mechanisms of injury were observed in this study. the possible reasons for the different types table 3. type of injuries sustained* n (%) haematoma/contusion/bruise 43 (33) muscle rupture/strain/tear/cramp 38 (29) sprain/ligament injury 30 (23) other bone injury 7 (5) tendon injury/rupture/tendinosis/bursitis 2 (2) concussion with/without loss of consciousness 2 (2) abrasion 2 (2) lesion meniscus/cartilage 2 (2) laceration 2 (2) fracture 1 (1) other 1 (1) total injuries 130 (100) *data are expressed as a per cent of the total number of injuries. table 4. injuries sustained by violation of the laws* n (%) no violation of the laws 99 (76) violation resulting in free kick/penalty 24 (18) violation resulting in yellow card 6 (5) violation resulting in red card 1 (1) total injuries 130 (100) *data are expressed as a per cent of the total number of injuries. sajsm vol. 27 no. 1 2015 19 of injury are multidimensional. for example, factors responsible for this injury pattern may include the different style of play (african v. european), vision of the game, skill, difference in fitness levels, player’s strength, difference in preparation and training methods, nutrition and the mental state of players. further studies are required to determine specific contributing factors in sa football. recurrent injuries are part of the season injury profile, although they represent a smaller part of the profile (12%). the relatively small percentage of recurrent injuries may be related to better management of injured players owing to epidemiological studies that have des cribed the risks of injuries[12] and of sustaining recurrent injuries. [6] for example, more focus is placed on preventing injuries through correct warm-up[13] and exercise programmes.[14] it has been shown that adopting these principles results in a reduction of recurrent injuries. the midfielders and defenders in this study sustained the most recurrent injuries. identifying the injuries and risks, and intervening with prevention programmes, may reduce the risk of injury in the following season.[13,15] however, most injury prevention programmes may assist in reducing the risk of overuse injuries. trauma is due to direct contact. therefore increasing awareness of these type of injuries, strengthening high-risk contact areas on the body, improving proprioception, agility, coordination, neuro muscular control,[16] reaction-response time (reflex-reaction exercises)[17] and core stability[18] may reduce the incidence of contact injuries. the injury patterns differed depending on the players’ position. in this study, midfielders sustained the most injuries compared with any other player position. a similar injury pattern was described in female professional players participating in the women’s united soccer association league.[19] however, another study on african players showed that defenders sustained the most injuries over a full season, followed by forwards, midfielders and goalkeepers.[20] in this study, 24% of all injuries sustained over a season were owing to unfair play. inconsistent refereeing during the season may compound this.[21] these statistics may support the call for a video referee, and education for both players and referees. there may also be a need to improve the laws of the game to protect players.[22] no studies have conclusively described the injuries sustained by violation of the laws. this is an important part of assessing the manner in which the injury is sustained and requires further research. conclusion the importance of assessing the incidence of injury and exposure times of footballers playing in a club cannot be underestimated. a better understanding of the underlying risk factors, exposure to injury and mechanisms of injury in sa football players should be promoted. it is therefore strongly suggested that a standardised injury surveillance protocol be established in all the teams in the psl; this protocol should run through the different leagues under the jurisdiction of the sa football association (safa). user-friendly software programs have been designed specifically for this purpose; therefore, injury surveillance using these protocols should become standard practice for all teams. acknowledgements. the authors would like to acknowledge mr george comitis (ceo of ajax cape town (ct) football club at the time) who supported the study, mr gavin benjefield, mr lorenzo meyer, mr craig von weilligh (ajax ct medical team), who assisted with data collection, and the players of ajax ct who participated in the study. references 1. maffulli n, caine dj, eds. epidemiology of pediatric sports injuries: team sports. basel, switzerland: karger, 2005. 2. ekstrand j, tropp h. the incidence of ankle sprains in soccer. foot ankle 1990;11(1):41-44. [http://dx.doi.org/10.1177/107110079001100108] 3. ekstrand j, waldén m, hägglund m. a congested football calendar and the wellbeing of players: correlation between match exposure of european footballers before the world cup 2002 and their injuries and performances during that world cup. br j sports med 2004;38(4):493-497. [http://dx.doi.org/10.1136/bjsm.2003.009134] 4. fuller cw, ekstrand j, junge a, et al. consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries. br j sports med 2006;40(3):193-201. [http://dx.doi.org/10.1136/bjsm.2005.025270] 5. brooks jh, fuller cw. the influence of methodological issues on the results and conclusions from epidemiological studies of sports injuries: illustrative examples. sports med 2006;36(6):459-472. [http://dx.doi.org/10.2165/00007256-20063606000001] 6. hägglund m, waldén m, ekstrand j. previous injury as a risk factor for injury in elite football: a prospective study over two consecutive seasons. br j sports med 2006;40(9):767-772. [http://dx.doi.org/10.1136/bjsm.2006.026609] 7. woods c, hawkins r, hulse m, hodson a. the football association medical research programme: an audit of injuries in professional football-analysis of preseason injuries. br j sports med 2002;36(6):436-441. [http://dx.doi.org/10.1136/ bjsm.36.6.436] 8. cromwell f, walsh j, gormle j. a pilot study examining injuries in elite gaelic footballers. br j sports med 2000;34(2):104-108. [http://dx.doi.org/10.1136/ bjsm.34.2.104] 9. ekstrand j, hägglund m, waldén m. injury incidence and injury patterns in professional football: the uefa injury study. br j sports med 2011;45(7):553-558. [http://dx.doi.org/10.1136/bjsm.2009.060582] 10. dvorak j, junge a, derman w, schwellnus m. injuries and illnesses of football players during the 2010 fifa world cup. br j sports med 2011;45(8):626-630. [http://dx.doi. org/10.1136/bjsm.2010.079905] 11. hawkins rd, fuller cw. a prospective epidemiological study of injuries in four english professional football clubs. br j sports med 1999;33(3):196-203. [http:// dx.doi.org/10.1136/bjsm.33.3.196] 12. arnason a, sigurdsson sb, gudmundsson a, holme i, engebretsen l, bahr r. risk factors for injuries in football. am j sports med 2004;32(suppl 1):s5-s16. [http:// dx.doi.org/10.1177/0363546503258912] 13. soligard t, myklebust g, steffen k, et al. comprehensive warm-up programme to prevent injuries in young female footballers: cluster randomised controlled trial. bmj 2008;337:a2469. [http://dx.doi.org/10.1136/bmj.a2469] 14. dvorak j, junge a, chomiak j, et al. risk factor analysis for injuries in football players. possibilities for a prevention program. am j sports med 2000;28(5):69-74. [http:// dx.doi.org/10.1177/28.suppl_5.s-69] 15. soligard t, nilstad a, steffen k, et al. compliance with a comprehensive warm-up programme to prevent injuries in youth football. br j sports med 2010;44(11):787793. [http://dx.doi.org/10.1136/bjsm.2009.070672] 16. filipa a, byrnes r, paterno mv, myer gd, hewett te. neuromuscular training improves performance on the star excursion balance test in young female athletes. j orthop sports phys ther 2010;40(9):551-558. [http://dx.doi.org/10.2519/jospt.2010.3325] 17. borghuis aj, lemmink ka, hof al. core muscle response times and postural reactions in soccer players and nonplayers. med sci sports exerc 2011;43(1):108114. [http://dx.doi.org/10.1249/mss.0b013e3181e93492] 18. leetun dt, ireland ml, willson jd, ballantyne bt, davis im. core stability measures as risk factors for lower extremity injury in athletes. med science sports exerc 2004;36(6):926-934. [http://dx.doi.org/10.1249/01.mss.0000128145.75199.c3] 19. giza e, mithofer k, farrell l, zarins b, gill t. injuries in women’s professional soccer. br j sports med 2005;39(4):212-216. [http://dx.doi.org/10.1136/ bjsm.2004.011973] 20. azubuike so, okojie oh. an epidemiological study of football (soccer) injuries in benin city, nigeria. br j sports med 2009;43(5):382-386. [http://dx.doi.org/10.1136/ bjsm.2008.051565] 21. fuller cw smith gl, junge a, dvorak j. an assessment of player error as an injury causation factor in international football. am j sports med 2004;32(1):s28-s35. [http://dx.doi.org/10.1177/0363546503261247] 22. andersen te, engebretsen l, bahr r. rule violations as a cause of injuries in male norwegian professional football: are the referees doing their job? am j sports med 2004;32(1):s62-s8. [http://dx.doi.org/10.1177/0363546503261412] j o u r n a l o f t h e s a s p o r t s m e d i c i n e a s s o c i a t i o n sports miedicinie rugby violence condem eddie king on triathlons sports medicine continuing education course r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) diclophenac sodium j l ^ m o pnrerir rnaied tablets for full prescribing information consult mdr or package insen or ciba-geigy (oil) 929-9111 25mg enteric coaled tablets reg. no. g/3.1/83 s3 o t l a n e n freedom to walk, jump, ft work i ciba-geigy i sport injury f rehabilitation 'pr o g r a m m e r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 1 contents journal of the s. a. sports med/c/ne tydskrif van die s. a. sportgeneeskundevereniging ciba-geigy 17-20 w m editorial comment rugby violence condemned e l interview eddie king on triathlons h rugby digest scientific physical conditioning for rugby 151 abstracts water-soluble vitamins not safe in megadoses hdl-c concentrations in female athletes treating patella tendinitis learning to play tennis without the fear of losing "high-lmpact" aerobics may be hazardous to your health f£] feature potential psychological dangers of jogging ce1 bookreview f73 sasmaupdate international speakers for 1987 congress sports medicine continuing education course [h running digest physiotherapy and the long-distance runner editor in chief dr c noble mb bch, fcs(sa) associate editors dr t noakes mb chb, md dr dawie van velden mb chb (stell), m prax med(pretoria) advisory board medicine: dr i cohen mb chb d obst, rcoc orthopaedic traumatology: dr p firer bsc (eng) mb bch (wits) m med (orthokwits) brig e hugo mb chb, mmed (chir) orthopaedics dr jc usdin mb bch, frcs (edin) cardiology: col dp myburgh sm mb chb, facc physical education: hannes botha d phil (phys ed) gynaecology: dr jack adno mb bch (wits) md (med) dip o&g (wits) front cover: transparency courtesy of s a sports illustrated. the journal o f thesa spores medicine association is exclusively sponsored by ciba geigy (pty) ltd. the journal is produced by bates hickman and associates (pty) ltd., po box 783776, sandton 2146. the views expressed in this publication are those of the authors and not necessarily those of the sponsors or publishers sportbeseringsen i sport injury and kardiorehabilitasie | cardiac rehabilitation program programme august 1986 vol 1, no 2,1986 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial commenl rugby violence condemned dr clive imoble mb bch, fcs (sa), editor-in-chief he recent burger gelden huys rugby incident in which new zealand cap­ tain andy dalton was punched from behind and suffered a broken jaw must, from a medical viewpoint, be condemned in the stron­ gest terms. one of the major aspects of the prin­ ciples of medical care is the prevention of injuries in south africa dirty play has become part of the game. it is a fac­ tor which can be prevented by stricter control. it is about time that the great game of rugby be taken out of this sphere of barbarism. to a large extent the so­ lution is quite simple and calls for stric­ ter refereeing and far more severe punishment. it was interesting to note that the welsh referee, mr roland, allowed no dirty play in test matches, largely due to the fact that he made it known that any player guilty of misconduct would be kicked o ff the field. at a recent high schools rugby game, l saw one player deliberately kick another. his punishment from the referee was to be sent to the "cooler box" — for possibly one minute — and then being allowed to play again. this is obviously inadequate punishment. i would like to see dirty play stamped out at grass-roots level and feel strong­ ly that such acts of violence on the rug­ by field should be penalised. not only should the player be sent o ff the field but he should be unable to play for a number of games, depending upon the degree of violence involved. should he commit further acts of violence, des­ pite such disciplining, then he should be banned for good. the school principal should take action against him as a per­ son who has grossly degraded the name of the school. a similar punish­ ment system should take place at senior level as well. suitable touch judges should also be selected for all games. one of their main responsibilities would be to spot dirty play. the referee must be fully august -1986 vol 1, no 2, supported by rugby administrators in their condemnation of dirty play sasma continuing medical education programme this programme, which is aimed at general practitioners will also be suita­ ble for physiotherapists and other in­ terested paramedics. the course will take place at wits university on august 8 and 9. it is hoped that all doctors who are interested in sports medicine and who wish to gain further knowledge of sports medicine will attend. topics to be discussed include sports traumatology, physiology, psychology, psychiatry and cardiology. it will be a comprehensive programme giving general practition­ ers a better insight into the manage­ ment of his sports patients. the general public has often consult­ ed alternative medical practitioners as they feel that many doctors do not have sufficient interest or knowledge to treat their sport problems, it is hoped that this congress will help to change this viewpoint. comrades marathon injuries the comrades marathon has come and gone for those interested in sports medicine it was a busy time, especially pre-comrades when many training in­ juries were reported. most of these injuries are related to excessive training on bodies which have not adequately adapted to the stress­ es imposed upon them. most practi­ tioners see at least four times as many novices as experienced runners with ini juries due to comrades training. the experienced runner appears to know his body and also is more capa­ ble of adapting to stress the beginner, fearing the 90 km run, tends to over­ do his training in order to make sure that he is fine on the day. i 2r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) unfortunately he often doesn't make the day due to injury. shortly before the comrades mara­ thon such factors as correcting bio­ mechanical abnormality or even reduc­ ing the main cause of problems — ex­ cessive distance, speed or hill training — cannot be adequately implemented. to a large extent treatm ent must fol­ low the race. such modalities as psysiotherapy and the application of ice are extremely helpful. however the use of cortisone and non-steroidal anti-inflammatory agents play a major role. it has become clear to me that there has been a drop in the injury rate, very possibly due to the excellent advice given by many experienced runners and clubs adequate training program­ mes have also helped to prevent inju­ ries i only hope these will continue into the future vottanenfrin sports injury and trauma. diclophenac sodium 50 mg y (enteric coated tablets)** ciba-g ho. hi/3.1/253 (wet/act 101/1965) 12 a-geigy (pty) ltd p.q, box 9 2 isa n d o 1 6 0 0 for full prescribing inform ation please refer to the m.d.r. ^ c u s fi9 8 6 vol 1, no 2,1986 dangers of aerobics with increasing leisure time available and a very definite tendency by the general population to improve the state and function of their bodies, aer­ obics has become a popular form of ex­ ercise unfortunately, this has not been without problems the most significant has been the injury rate which even oc­ curs in such a well-controlled exercise programme as aerobics. exercises such as repetitive touching o f the toes and excessive stretching, p articu larly o f the b a llistic type as o ccu rs in som e aerobic classes, overioadesthe ligam ents, m uscles and d iscs in the spine and creates p ro b lem s." two factors are largely responsible as in all forms of physical fitness, the body has to adapt to the stresses imposed upon it. a common practice in aerobic classes is that the rank beginner com­ petes with the experienced exponent, thus loading his body and causing a multiplicity of injuries chief among these are shin splints, patella injuries, and backache backache is largely due to the second problem — that is executing movements which are out of the normal pattern. abnormal loading results exercises such as repeti­ tive touching of the toes and excessive stretching, particularly of the ballistic type as occurs in some aerobic classes, overloades the ligaments, muscles and discs in the spine and creates problems it is essential that all aerobic instruc­ tors/instructresses be given lectures in anatomy and bio-mechanics, as well as obtaining knowledge in the prevention and early treatm ent of injuries, in this way aerobics, with its fantastic physical rewards, will go a long way towards im­ proving the health of our nation without creating major disability. 3r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) interview; eddie king on triathlons he old adage that "you don't get older, you only get better" applies to triathlon champion dr eddie king. in the 1986 iron man triathlon "tiffy" as he is known to his friends won in the record time of 7 hr 27 min 24 sec proving that he is one of the most outstanding en­ durance athletes in the world. the delmas doctor-dairy farmer likes nothing better than a challenge and this is why he took up "tri-ing" or "rubber-braining" in the first place he recently told the star.• "i watched the inaugural competition on television and saw the winner, tim cornish, look­ ing so fresh and good, he was absolute­ ly radiating energy and vitality. he then said in the interview that the triathlon would always favour the canoeists and said it would be many years before a specialist runner or cyclist won the event as canoeing was such a specialist sport. "so immediately i had a point to prove and i had something to aim f o r between 1969 and 1974 king represented western province at track and cross country. in preparation for the gruelling endurance events to come in the years ahead he notched up his best standard marathon time of 2 hr 22 mins at stellenbosch in 1971. in his debut triathlon in 1984 king finished fifth. since then he has never looked back and added the 1985 and 1986 titles to his credits. if you have any iron man ambitions be prepared to train almost non-stop. for eddie king training has become a way of life not only for himself but for his wife, tertia, and baby daughter louise as well. eddie has all the qualities needed for an endurance athlete. he is as lithe as whiplash, very determined when he has a set goal and pulls out all the stops when the going gets tough. these abil­ ities are self-evident when you consider that he takes less than 7vi hours to cover 21 km of canoeing, 97 km of cy­ cling and, finally, a 42,2 km standard marathon. triathlon stars must have under­ standing wives as eddie readily admits he told a newspaper reporter: "i've got a very special wife and i know for a fact that if it wasn't for her i wouldn't have come anywhere near to achieving what i've done so far:' there is no opportunity for a train­ ing rest. when one iron man competi­ tion is completed he starts training for the next one in a year's time. his maxi­ mum training is about 25 hours a week averaging out at about 20. king manages to be a doctor, farm ­ er, agricultural mechanic, husband, father, athlete and friend to many sportsmen around the country. tertia king believes the discipline of running the delmas farm and eddie's ability to function best under pressure have contributed to his triathlon suc­ cesses. "whether you want to or not you have to start milking the cows at 6.30 am. then there are many other respon­ sibilities including managing the farm workers. eddie is responsible for repair­ ing anything that breaks he is the family's handyman." in a recent inter­ view dr king spoke to the journal o f the sa sports medicine association about his life, motivation, training methods and philosophy. "i graduated from the medical school at the university of cape town in 1975 and then followed a varied career path. utilising creative incompetence i star­ ted breeding american holstein milk cows in the delmas district. little did i realise it then but l would also be part of a new craze called tri-ing or rubber braining. nothing ever changes and all i want is to have lived well and to die well. as a teenager my father used to take me on hikes on his bushveld farm. i think he derived sadistic pleasure from reducing me to a physical and emotion­ al wreck and allowing me to become to tally disorientated and lost. rounding each koppie he would say: t h e house is just around the next corner. pushing yourself to the limit and then having to start all over again soon — this is part of the lunacy involved in august 1986 v 0 l1.n 0 2, 19m ar ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) triathlons. training for the iron man competi­ tion is all sweat and no pleasure. hear­ ing bruce fordyce say that his training is enjoyable makes me very envious. starting to prepare for next year's event is usually the second day after this year's competition has been com­ pleted. building up to 25 hours per week before the race dem ands sacrifice, compromises and a constant trade-off. i try to peak about three months be­ fore the race doing six hour training sessions once a week. this comprises two hours paddling followed by 3 to 3'a hours o f 90 km cycling and soon after that a 10 km run. doing this totally alone forces one to depend on oneself. towards the end of these sessions you feel like eating the grass on the side of the road. you hear skipping reels of rhyme flow through your brain: jack be nimble, jack be quick...' over and over again. this got me very worried at one stage and instead i tried to memorise hamlet. i kept sheets of prose under my cycling top just in case i forgot a line but this can be very dangerous on a carbon fibre vitus cycle at 40 km/hr the agony of such a long session real­ ly scares me although i try to experi­ ment with pain by concentrating on different parts of my body, blotting out my environment as best i can. mind bending is certainly a fair description of my enterprise when the pain becomes unbearable and the weariness draws me down, i have a dream or fantasy in which i am flying effortlessly. if we don't have dreams what is there left for us. competition: competition at the top is certainly not between people but be­ tween individuals and the course l have to conquer the elements; something like fire and ice fighting nature is more difficult and requires more imagination than beating people. perhaps to do 90 percent of my training alone in the wild, open spaces does it for me at 37 i really can't com­ pete physically with the eternal spring' of youth and i think my forte has been reached. from now on the springbok canoeists, cyclists and runners will have it more their own way. transcending pain of course is all im­ portant in these events experimenting with that pain and using it to one's own advantage — for instance masking fa­ tigue (because they are not the same) — is exhilirating when achieved people often wonder why we subject ourselves to this physical and mental onslaught as humans we are curious about just how far we can push our­ selves. we do not do this for the tele­ vision cameras or the feeling that af­ ter a race we have made love to thou­ sands of spectators, but rather that we have bettered ourselves and pushed the boat a little bit further up the beach! training: top world pro's like molina, scott and tinley are doing 30 to 35 hours a week of intensive cardiovascu­ lar stress events — usually three events per day in three or more sessions — eg. a 16 km easy run in the morning fol­ lowed by an easy 90 km bike ride in the afternoon. triathlons demand more from athletes than any other sport in the world. i often do three events in one day, leaving the run for last; 10 km into the run i frequently get that high in the sky hypoglycaemia feeling and really have to concentrate on finishing the run i never plan quality or anaerobic ses­ sions. i do them only when i feel good or when my body allows me to. the stress associated with the psy­ chological build-up to an interval ses­ sion is too much for me to handle and therefore l just let them happen — changing a long run into a fartlek out­ ing as my psyche allows. i believe that only ballet dancers train as hard as tri athletes. we are truly aerobic death machines. age: t h e old order changeth, yielding place to new'. certainly next year the younger guys will have it all their own way. but one should also not forget carlos lopes (37), the world marathon and the wonderful is still winning record-holder, cary player veteran golf approach: really very little athletes as our become rubberised and such higher func neglected. overtaking springbok canoeist rory pennefather in 1985 at 30 km into the run i said: 'rory, this is the final ana­ lysis; the circle is now complete: this has no intended malice but seemed to have a stagcom petitions. "psychology has to do with tri brains yearly on x tions are gering effect as was evident on televi­ sion. my great fear is that i may be selling my soul for glory. remaining true to myself and my ideal is very difficult. motivation is my greatest problem. get­ ting out o f bed in the morning is ex­ tremely hard. the day gets easier as it goes on but the initial force needed to exit from the womb into the cold and hostile world o f reality takes its toll every time. it seems that there is a very close relationship between motivation and stress. they are certainly inversely proportional. in my daily activities as stress increases i find it harder to kin­ dle the motivation so essential to proper training. i divide stress into three — namely work, social and sport. when the peo­ ple i work with in my medical practice don't understand my needs or pres­ surise me into longer hours my train­ ing always suffers. i feel that they don't seem to accept that one can do both well. for them success on the playing field necessitates poor work perfor­ mance. equating me with a full-time professional who does not have fixed employment hurts very much. similar­ ly family trauma o f any kind leads to stress and that can have a negative ef­ fect on athletic performance. i hasten to add that if it were not for my exceptional wife my sporting achievements would most certainly have amounted to nothing. she is the farm manager and carries the work pressures at peak times l only eat and sleep at the farm. many authors seems to think that stress can have positive effects as well — but i have yet to become so enlightened. life for me is a trade-off between the essential things i have to do and my 3 to 3'a hours a day of training. how long my life will be so full i don't know. coming first is lovely but winning is the best, and in winning our lives as a whole count. victory is a fickle thing — much like a woman's mind. it is always borrowed but never owned; elusive '“till the next race". r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) scientific physical conditioning for rugby m c siff, bsc hons msc neuromuscular research laboratory physiology department, university of the witwatersrand, johannesburg. he need for rugby train­ ing to evolve from a tradi­ tional art to a definite blend of science and art is long overdue regret­ tably it has taken a great __ ___ deal of adverse media publicity on the unacceptable extent of serious injuries to convince the rugby fraternity that training of players and coaches has to become far more scientific the expertise for establishing a scien­ tific training methodology for rugby al­ ready exists in south africa. there are outstanding exercise physiologists, sports doctors and experienced rugby strategists at institutions throughout this country, but fusion of their collec­ ted knowledge has not yet occurred. in addition, much relevant information may be extracted from the highly de­ veloped training systems used in ameri­ can football and soviet athletics preliminary considerations among the most important factors required for establishment of scienti­ fic rugby training are the following1. training m ust be a year-round process an off-season lay-off followed by one to three months of intense pre season training is a major reason for the generally low levels of fitness among our rugby players and the elevated incidence of injury during the early and late season periods 2. specialist coaches are required for the different components of rugby training. very few single coaches are equipped to handle strategic skills, kick­ ing skills, scrumming skills, strength training, psychological preparation, bio­ mechanical analysis, fitness testing and rehabilitation routines ju st as there is a playing team, so there has to be an efficient coaching team comprising all relevant experts 3. scientific speed-strength training has to be incorporated into every play­ ers programme it is not possible to en­ hance s ig n ific a n tly any player's strength and speed without sup­ plementary gymnasium training using appropriate exercises sequenced care­ fully in terms of total volume, average load intensity and restoration intervals as most gymnasium owners have no formal training in designing scientific supplementary conditioning routines, players should be provided with scien­ tific programmes prepared by experts and supervised by accredited gym in­ structors 4. periodic scientific testing of the var­ ious components of player fitness is necessary. ideally, a fitness screening session to test strength, speed, cardio­ vascular endurance and suppleness should be administered at the first practice of the season. any player who fails this test should be excluded from official practices until he reaches an ac­ ceptable level of overall fitness 5. rugby training sessions must be devoted largely to enhancing technical and strategic skills, rather than to im­ proving general physical fitness rugby players must acquire the necessary fiti ness in their own time and not waste an expert rugby coach's time in running physical training classes 6. all players must learn the skills of i running, falling, tackling and all aspects j of ball-handling. efficiency of play and protection from injury depends on ac­ quiring high levels of neuromuscular skill in all types of movement encoun' tered in rugby for instance, any team august 1986 vol 1, no 2,19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) all of whose players could drop-kick ac­ curately, would have a formidable ad­ vantage over another team with a few specialist kickers needs analysis an analysis of the specific fitness needs of forwards and backs is neces­ sary for the design of a scientific train­ ing programme coaches need to un derstand the implications of the con­ tributions played by the three distinct energy systems of the body (aerobic, lactic acid, anaerobic) and the major muscle-fibre types too many coaches devote unneces­ sary and counter-productive effort to a * in-season aerobic training, when it should be realized that the rugby play­ er never relies predominantly on aero­ bic energy mechanisms the benefits of aerobic training accrue during the off-season period in season aerobic training can diminish strength, speed and agility, while increasing one's sus­ ceptibility to overtraining injury and stagnation. an understanding of the rugby play­ er's needs may be gained by analysing the time devoted to different events during the typical rugby match. a french study reveals th e following statistics for the average game (1 ): •there are 80 sequences of action ifk'u st 1986 vol 1, no 2,1986 lasting 27 minutes of actual playing tim e • there are an average of 40 scrums lasting up to a maximum of 20 seconds • over 70% of rucks and mauls last five seconds and the remainder 6-10 se­ conds 85% of all sequences last less than 20 seconds 56% of all sequences last less than 10 seconds 32% of all sequences last less than 5 seconds • all top club level forwards cover an average o f 6 km; backs cover 4 km • 33% of the forward's distance is at top pace, whereas it is 50% for backs since reliance on the aerobic system becomes dominant for sustained exer­ cise lasting more than about 1 2 min­ utes (2) it is clear that rugby players, irrespective o f position, require high levels of anaerobic and lactic acid sys­ tem fitness the main value of long slow-distance (lsd) aerobic training lies in the off-season conditioning of ten­ dons, ligaments and cardiovascular sys­ tem to enable the player to cope with the in-season stresses of intensive in­ terval and strength speed activity. peri­ odic low-value in-season aerobic ses­ sions each lasting no more than 15 minutes assist in enhancing recupera­ tion and maintaining an adequate lev­ el of cardiovascular fitness period isation the overall long-term structuring of training to maximise performance to coincide with important matches is referred to as periodisation. periodisa tion recognises the fact that there are three major phases of all training: p re p a ra tio n , co m p e titio n , p o st­ c o m p e titio n (or tra n sitio n ). the preparatory phase may be broken down further to general physical prepa­ ration (gpp) and specialised physical preparation (spp). gpp provides all-round physical con­ ditioning in stamina, speed, strength, suppleness and the other basic compo­ nents of fitness, while spp concentrates on exercises which are more specific to the particular sport, such as scrum­ ming and kicking proficiency in rugby. characteristically, the gpp phase may include participation in a variety of different or physical activities which provide low-intensity, all-round condi­ tioning. participation in social basketball and volleyball would be eminently suit­ able for the rugby player's gpp, especial­ ly in the transition period from gpp to spp the volume of exercise should be high during gpp and its intensity low, then a gradual transition to spp should occur, during which the exercise volume must decrease and its intensity m ust increase. at the same time, in­ creasing emphasis should be laid on im­ proving the techniques required by the specific sport. the gradual overload principle is constantly adhered to through all train­ ing cycles to ensure that an adequate but not excessive increase in training stimulus is imposed on the body in­ dividual workouts should be alternated in terms of light, medium and heavy loading so as to ensure high efficiency for each match and maximum efficien­ cy for the most important matches two successive heavy workouts should be avoided and no pre-match session should be too intense or too close to the match, unless it is devoted to light skills training. supercompensation it should be remembered that any heavy loading temporarily exhausts the body's energy stores and causes a drop in strength, speed and endurance however, within a few days, the body not only recovers but can actually over recover or "supercompensate" to pre­ pare the body for subsequent loading. however, if a strenuous training session is imposed before sufficient recovery has occurred, supercompen­ sation will be inhibited and overtrain­ ing, injury or depression may result the player will be compelled to rest or train inefficiently so that his performance will fluctuate between unplanned highs and lows a similar, though safer situation will be produced if subsequent strenuous training is imposed well after recovery has occurred. supercompensation will be minimal and performance will diminish gradually. the maximum physical conditioning effect occurs if subsequent loading takes place between these two ex­ treme situations, imposed regularly a short time before full recovery is com­ plete in addition, every three weeks of heavy training should be followed by a fourth week of low volume, sub-maxi­ mal training to maximise supercom pensation. efficiency of supercompen sation can be enhanced by use of res­ toration measures including massage, active or passive rest, electrostimula­ tion, saunas and similar physiothera­ peutic techniques speed-strength training the rugby player is a contact sports­ man who requires high levels of strength, speed and muscular endur­ ance therefore, bodybuilding type training is of limited value to him, par­ ticularly if it includes no explosive movements. some of the methods of olympic weightlifting training are far more suitable for rugby training, in fact, american football, similar in many ways to rugby, requires all its players to perform heavy, low-repetition power cleans to improve overall power. 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) odybuilding and power1 lifting training do not 9 ■ include phometric jump ^ ing exercises used by • i m o st a m erican foot bailers to enhance the explosive power neces­ sary for jumping, throwing, kicking and sprinting, a properly designed speed-strength programme necessitates a balanced sequence of isometric, concentric and eccentric slow and explosive exercise regularly varied to prevent stagnation and injury. (3). structure of the training session each training session should be a mi­ niature version of the periodisation sys­ tem: preparation, loading, transition. the preparation phase consists of a light general circulatory warm­ ing followed by general static flexibility manoeuvres and finally by specific flexibility procedures using static or pnf (proprioceptive neu­ romuscular facilitation) stretching to prepare sp e c ific a lly tho se muscle groups about to be used in the first exercise. the grad ual overload p rin ­ ciple is applied in the loading phase, with each a c tiv ity progressing from low to high intensity, with fewer re­ petitions being performed at high intensity. in^§ the gym nasium '' exercises are classi­ fied in terms of sets of a certain number of repeti tions with a prescri­ bed weight. on the rugby field sequences can be classified in terms of sets of a cer­ tain number of sprints, scrums and so on. the concluding transi tion (post-training) phase consists o f a gradual cool ing-down period similar in structure to the initial warm up/general flexibility phase. it can be particularly useful to integrate psychological pre­ paration (such as motivation, technique visualisation, relaxation and ideomotor training) into the preparatory and concluding i f p / phases of every workout. selection of supple­ m e n ta ry exercises exercises should be chosen to suit the needs of the indi­ vidual so as to enhance his speed-strength performance, functional suppleness, general fitness for his specific rugby needs and his resistance to in­ jury. activities should never be permitted which are detrimen­ tal to performance or health. coaches need to be made aware o f the fact that every exercise can be done incorrectly and that certain exercises are poten­ tially harmful. for instance, many tradi­ tional movements such as leg raises, bunny hops, straight-legged sit-ups, hur­ dler's stretch, running with partner on the shoulders, toe touching, star-jumps, press-ups with sagging lower back and ballistic stretches can be dangerous for vital structures of the body including ligaments, joints and nerves (4). concluding remarks the above information by no means covers the entire extensive field of scientific physical conditioning for rugby. it does not address the indivi­ dual needs of forwards and backs, \ nor does it prescribe specific rou \ tines for strength or stamina. .■ \ what it does attempt to do is ^ \ introduce the relationship be v tween rugby training and relevant physiological prin > ciples in an effort to in crease awareness that ; scientific training can enhance perform ance and prevent injury. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) water-soluble vitamins not safe in megadoses he assumption that the t water-soluble vitamins — b complex and vitamin c are non-toxic is inaccu­ rate. a cco rd in g to carol potera writing in the physician sportsmedicine, megadoses of b vitamins have been reported to cause peripheral neuropathies such .as numbness, ataxia and paralysis. dr robert 0 voy, chief medical officer and director of sports medicine for the us olympic committee in colarado springs, united states, stated recently that although even severe cases of paralysis are usually reversable, he warned that 'the symptoms can go on a long time before they are linked to a vitamin". added potera: "b vitamins are known to produce other side effects. ellen coleman, a nutritionist at riverside cardiac fitness in riverside, calafornia, described a runner who took 20 times the recommended daily allowance (rda) for niacin before a 10-kilometre race "he was bright red and itching and scratching", added coleman, because niacin is a vasodilator. she also said that thiamine megadoses have caused an anaphylactic shock. in addition, two grams of vitamin c — the cold preventative dose — causes gastro-enteritis, diarrhoea, colitis, and kidney stones, according to dr voy. in some cases when the dose was sudden­ ly stopped, rebound scurvy occured. "what causes the side effects?' asked potera. "at high doses, vitamins stop acting as vitamins and act instead as pharmacological agents. for example, the toxicity of vitamin b6 (pyridoxine) |s probably related to its membership m the pyridine family, a group of neuro­ toxic drugs impurities in vitamin prepa­ rations could also be responsible. the food and drug administration allows synthesised vitamins to have a two per­ cent impurity level as long as the im­ purities are non-toxic at the rda. but when taken in megadoses, the impuri r|es can far exceed the limits of safety1: potera, the physician and sports rnedicine, vol 14, no 3, march 1986. august 1986 vol 1, no 2,1986 hdl-c concentration in female athletes serum h ig h -d e n sity lipoprotein cholesterol (hdl-c) levels and percent hdl-c were significantly higher in nine female endurance runners, than in equal groups of female weight trainers and sedentary female controls, an american study has shown. weight trainers and controls showed no significant differences in hdl-c and percent hdl-c subjects who had higher hdl-c levels were more likely to be non smokers who consumed little alcohol and did not use oral contraceptives. no significant dose-response relation­ ships were found for either runners or weight trainers when daily training du­ ration, weekly training frequency, and weekly mileage were correlated with hdl-c. a cross-group com parison showed that females who were non sm okers, co nsum e d low weekly amounts of alcohol, and did not use oral contraceptives had higher hdl-c levels. differences in group hdl-c con­ centrations were associated with specific training methods. d w morgan, r j cruise, b w cirardin, v lutz-schneider, d h morgan and m wang. the physician and sportsmedi­ cine, vol 14, no 3, march 1986. ideating patellar tendinitis how serious is patellar tendinitis, also known as "jumpers' knee" (as is com­ mon in basketball players)? tennis trainer bill norris, advises world tennnis: "basically, you have an inflammation of the ligaments in the bottom half o f your knee cap tendons, the patella. if your tendinitis is chronic, your knee is probably always sore, es­ pecially in the morning. the acute stage is marked by the skin feeling hot to the touch and may also be sore and stiff after heavy exercise." he points out that the condition must be treated conservatively. use ice­ packs to reduce the temperature and swelling, and see a physical therapist or orthopaedist for galvanic, ultrasound or other electrical stimulation. "if you have such treatments continu­ ously — three or four days in a row — the blood supply to that area increases and the tendinitis is relieved", he adds. "on your own, try a whirlpool, hot baths or moist heat to help the circulation. ask you physician about a patella brace: this band fits below the knee cap, reducing the pressure and al­ lowing you to play with a mini­ mum o f pain. but once again, rest and treatment are crucial to recovery, as is a visit to an orthopaedist and quali­ fied physical therapist'. |g f. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) iv u i i . osteoaithntic o f m o vem en t the osteoarthritic specific innovators in the field of antirheumatic medicine diclophenac sodium 100 mg i < .r (n ilp rescrib ing information r r tin • mi 't fhiricage insert o r q ba-gpigy (<>lt >' •, ' •' «/// relieves pain restores mobilit1 on one tablet ^ p e r day r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) >986 vol 1, no 2 1986 d earning to play tennis without the fear of losing the secret of any game, the success of any game for a player, is to learn to play without the fear of losing. "if you create the attitude that you are not afraid of losing, the worst thing that is going to happen is that you may have a bit of a sleepless night," says pan cho gonzalez, writing in world tennis. "a lot of players make too much of the problem: they can't sleep, can't rest, can't eat, can't have fun. that's sup­ posed to be a disaster gonzalez adds that if tennis has this effect on you, perhaps you shouldn't play the game — or you should switch to something else. or perhaps you should stop playing games altogether, "but if you realise that all of us get beaten and that it is part of the game — because without being beaten, there is no room for improvement — you will be more relaxed. when you are more relaxed and playing better, you will win. "of course, this is assuming that you are practising in the proper way during your training session. you already have the ability to play well; so just relax, go out and make ^ you r sh o t and recognise that even the great players have to contend with learn ng how to lose." v o t t t t p p n t irw v v w j v i in sports injury and trauma. diclophenac sodium 50 mg (enteric coated tablets) reg ho. k/5.1/255 (wet/act 101/1965) e h c iba-g eigy (pty) ltd p.o. box 9 2 isando 1 6 0 0 for full prescribing inform ation please refer to the m.d.r. "high-impact” aerobics may be hazardous to your health american exercise authorities are recognising that "high-impact" aerobics can prove hazardous to students and instructors alike. according to time magazine a recent survey of 1200 students showed that 43 percent had suffered injuries. among 58 teachers the figure was an alarming 76 percent. other studies show similar results. few of the complaints seem to in­ volve serious damage to the back or the knees. more common are muscle aches and strains, usually of the shins and foot, which usually heal with rest. unyielding floors, often carpet over concrete, are being blamed for the un acceptably high injury rate comments time: “few owners of facilities can af­ ford to install highly resilient but high­ ly expensive floating floors. then, too, aerobics dancers often select the wrong footgear — for example, run­ ning shoes that cushion the heel rather than the ball of the foot. another problem is poor instruction from both the celebrities on video­ tapes and the gorgeous­ bodied leaders at health clubs." major failings said to be inade­ quate warm­ ups and cool downs, plus unflagging exhortations to do more, push harder and "go for the burn". peter francis, a biomechanics resear­ cher at san diego university, maintains that an aerobics dancer lands with a force equal to three times her weight. "on slow-motion tape you see a rippling of the skin. that's just indicative of the shock wave travelling up the body:' the american college of obstetri­ cians and gynaecologists is concerned about potential dangers and is recom­ mending changes. the college urged less intense workouts and issued guide­ lines for the average exerciser time reports that heart rate should not exceed 75 percent of the recom­ mended maximum; classes should be no more frequent than every other day; the aerobics portion should be limited to 30 minutes; and no more than four hops should be performed in sequence on the same foot. what is now being advocated is a gentler and increasingly popular form of aerobics that minimises jumping and jarring movements or eliminates them altogether other erstwhile aerobics dancers are abandoning hard floor for water and hydro-aerobics. time points out that the benefits are enhanced in water exercising limbs meet 12 times the resistance that they face in air. 11r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) potential psychological dangers of jogging timothy d noakes mb chb md metropolitan sports science centre, department of physiology, university of cape town medical school and author of lore o f running (oxford university press) s the running revolution of the late 1970s took hold and as the literature describing its benefits grew, it was only natural that a counter-literature should develop. the major contention o f this counter movement is that running is detrimen­ tal because it is "addictive" for the re­ mainder of this chapter we will con­ sider the arguments surrounding this running "addiction': one definition states that addiction occurs when involvement in an activi­ ty eliminates choice in all areas of life on this basis, an addiction must be dis­ tinguished from a habit, commitment or compulsion, none of which exclude all other activities. my experience is that the great majority o f runners are not addicted to the ex­ tent that running com­ pletely dominates all aspects of their lives. rather, i believe their running fits the des­ cription of a compul­ sion and the term ad­ diction is inappropriate it should also be not­ ed that society is selec­ tive in its judgement of compulsions. as james fixx (1977) has noted: "no one uses the word addiction when refer­ ring to people who spend ino rd in ate amounts of tim e mak­ ing money, playing at politics, or pursuing the opposite sex." activities which fixx suggests may be even more hazardous than "spend­ ing a quiet hour or two in a park or on a coun­ try road" but we should not allow fixx's master­ ful english to disguise the possibility that run­ ning in a park for up to two hours a day could in fact be as much a behaviour disorder as is working twelve or more hours a day. a feature of an addictive state is that withdrawal symptoms develop when the addict cannot partake of his addic­ tion. two authors have described the withdrawal symptoms which they con­ sider indicative of running's addictive's nature psychologist william morgan (1979), lists the following array of with­ drawal symptoms: "... depression and anxiety are usually accompanied by restlessness, insomnia and generalised fatigue. tics, muscle tension and sore­ ness, decreased appetite and constipa­ tion or irregularity often develop. in general, the benefits of vigorous exer­ cise are reversed... the scheduled daily run pre-empts important vocational and social commitments, causing work, family and friendships to suffer. in fact 12 addictive runners may totally alter their lifestyles to accommodate the priority of their running interest; this may in­ volve changes in diet, clothing, choice o f friends and even ca re e r michael sacks (1981) notes that the running addiction usually starts during a period of increased emotional stress in this regard, running is especially at­ tractive as it is in an easy skill to acquire and therefore provides a simple rapid solution to emotional distress. so powerful is this addiction that another writer has suggested that the united states congress should enact legislation requiring the following warn­ ing to be displayed on all running shoes, shorts or books: warning: the psychiatrist general has determined that jogging and running are hazardous to mental health and present a grave risk of contracting contagious quasirandomous wan deritis(qw) or "jogging about". sacks has emphasi­ sed particularly the psychological compo­ nent of these with­ drawal symptoms: "the ru n n in g a d d ic t is characterised by a com­ pulsive need to run at least once sometimes twice a day... if prevent­ ed from running, such runners become... pre­ occupied with guilty thoughts about how the body will decondi­ tion or deteriorate in some way. the running addict recognises the irrationality of those feelings and thoughts, but they are inescapa­ ble and can be relieved only by running:' w ith th is back­ ground, let us consider the arguments for and against this "running addiction" in more de­ tail. tlirn to page 20 august 1986 vol1.no 2,198' r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) executive stress by donald norfolk, arrow books stress, like nuclear energy, can be a power for good or a power for ill. the careers of many people are being cut short — by nervous breakdowns, heart attacks and the aptly named "executive burnout syndrome" — because they have not learned the secrets of stress management. others, meanwhile are carrying out rich and exciting lives by harnessing the energising powers of stress arousal. learning the basic survival tactics out­ lined in this book can make the differ­ ence between success and failure. there have been many recent develop­ ments in the field of stress research, which have been incorporated in the second edition of this book. everybody is under some stress each day of their lives — whether from job worries, domestic crises, financial trou­ bles or plain anxiety about the future. yet norfolk maintains that stress can be a vital, positive force for enriching life and helping people realise their full potential. in this revised edition the author ex­ plains how to recognise the danger sig­ nals of too much stress — and how to harness this immensely potent force for your own benefit. the british publication the economist called executive stress "a wise and vigorous handbook "for the individual who wants to come to terms with stress and to harness its positive aspects. this is a sensible book which can be read with profit not only by the harassed executive but by those who feel that the world is too much with them." commented the executive post: "the book is informative and gives sound helpful advice in a very readable nar­ rative style... its forte is its clear, lucid style and its sound, practical advice". running w ithout fear by dr h cooper, bantam books since the death of running guru jim hxx, the dangers of exercise have been hotly debated. jn his latest book dr cooper, an aero djc expert and director of the cooper uimc and aerobics centre in dallas, pro­ v e s guidelines for his safe approach auljubi 1986 vol1.no 2 ,1986 to exercise, along with explanations of the various risks involved. the author writes that what we face today is widespread confusion and ig­ norance about exactly what exercise can or can't do. in running without fear, he clears away the confusion and tries to set the record straight. "exercise is absolutely essential to good health. it is the cornerstone for any complete effort to reduce the risk of heart attack and sudden death. it is also a major key to an energetic, long life", he states. "above all i want to pro­ vide you with solid grounds to feel to­ tally confident as you fit aerobic exer­ cise into your own approach to good health and longer life. i want to show you how you can continue to run, swim, cycle, or dance and get the maximum health benefits of that aerobic activi­ ty without fe a r dr cooper offers guidelines on: • how to reduce the 11 "rules of risk" for developing heart disease • the danger and fallacy of the myth of invulnerability: that the more we ex­ ercise; the healthier we are •w hat constitutes a safe and effective stress test — plus the new cooper pro­ tocol, the state of the art procedure in stress testing developed at the insti­ tute for aerobic research • why the cool-down is the most dan­ gerous phase of exercise • how to avoid the jim fixx syndrome • how, when, and where you are at risk during exercise • how to develop your own persona­ lised and safe exercise programme • complete with illustrations, charts, self-evaluation tests, references, glos­ sary and index. it is easy to see why the physician and sportsmedicine magazine commented: "many very good commonsense recom­ mendations for specific aerobic exer­ cises, with emphasis on safety". this book is helpful for the general public... and valuable for physicians. being human — a day in the life of the human body by david bondanis, century pub­ lishing company. in tracing the course of a day in the body's life this book transports us to an extraordinary inner world of electric nerve impluses, tensing muscles, pump­ ing chemicals and racing cells. the author, david bodanis, describes movement, eating, anger, pain, desire, sex, contraception, relaxation, sleep and many other processes that might occur in an ordinary day. he writes with the vividness and clarity o f a thriller writer. magical moments are highlighted — like the development of a heart in a four-weeks-old foetus — and more bi­ zarre phenomenon such as the mites that live in the spaces around the base of the eyelashes, shaped like crocodiles and with eight legs and wriggly bodies. lavishly illustrated with unidue photo­ graphs, being human is truely fascinat­ ing. tendinitis: it's etiology and treatment by sandra curwin and william d stanish, collier macmillan international. tendinitis: it's etiology and treatment is a compact and readable volume which covers tendon structure and function; the etiology, pathology and mechanics of tendinitis; tendon healing, and the role of exercise in treating the disorder. while focusing on the forms of ten­ dinitis that are most common (achilles tendinitis, jumper's knee, tennis elbow), it also describes the other less fre duently encountered forms (shoulder, elbow, wrist, groin, hamstrings, shin), in­ cluding signs and symptoms and tips for differential diagnosis it presents a unidue programme of exercises, describes how it is applied to the various types of tendinitis, and sur­ veys the results of 200 cases in which the programme was used. a concise yet thorough approach, combined with a careful review of the clinical literature and presentation of a clinically proven exercise programme, makes this an ex­ tremely useful book for physicians, therapists, trainers, coaches and ath­ letes. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sport i rehab_______ programme ciba-geigy final phase rehabilitation of sports injuries and the role of isokinetic testing d r etrcsia prlrtsloo (m b c lib) p ro je c t le a d e r : ciba-g eigy s jx m injuries rehabilitation project, institute for sp u rts r esearch an d training,1 iniversity o f pretoria f d r etresict prinsloa the author o f this article, photographed in her laboratory with springbok rugby captain naas botha. s t n jr t c s i k<n s :im!irvinr tyx»irv.m vtitiih v nrwjrotey j’icm kvhall <m (?#45 j.ccuoni k fii'lwhthui-ur ntu mporitxwihh* ‘ whjiij; ' eiulletirr.o t w * 1 n icki »l v / htlx.fuuuc awwftilik itu m i a f h n u lb i•<>k fo> l s in g flu* c ]'b e xd a ta ttoctnitfim co m pu ter i 1 i r t t rjfk m v injtitw s v , \ s p o n k e n c c s k tin ij c , dee! x. jowi f> v rye turn ti l sfx/rthrsi'rinxs. krtchcfsinxim itchcfstroam ifitjitw ’i v lu j l'>"n no patient with a sports injury should resume his sport before being functionally rehabilitated — this could prevent rc-injurv to a great extent. the purpose o f functional rehabilita­ tion is to regain the following: 1. functional muscle power 2 cardiovascular fitness 3. muscle endurance 4. co-ordination and balance for sport specific activities ---------- 5. suppleness. the handling o f a sports injury requires a multi-disci­ plinary rehabilitation team. the members include: the patient, doctor, physio­ therapist, biokinetieist and trainer. the injury may be divi­ ded into 5 phases, viz: 1. the prophylactic phase 2. the injury and first-aid phase 3. the treatment phase 4. the primary rehabilita­ tion phase 5. the secondary rehabilita­ tion phase. the physiotherapist is responsible for the very im­ portant primary rehabilita­ tion phase. this phase starts as soon as possible after injurs’ eg. while still in bed after surgery or immediately aftera soft tissue injury. the physiotherapist helps the patient regain his kinetic function. once the patient is able to move with­ out pain the rehabilitation pro­ gramme continues. now follows sec­ ondary rehabilitation during which the patient must be rehabilitated function­ ally. tilts phase fells under the bio kineticists ■— in conjunction with the physiotherapist and trainer. the principles o f functional rehabi'' ‘ m litation are: 1. evaluating the patient repeatedly to monitor progress 2. exercising within pain limits 3progressively increasing resistance at which exercise takes place. an isokinetic test apparatus is ex­ tremely valuable in repeatedly evaluat­ ing a patient to monitor progresss. in knee injuries the first evaluation may for example be done when the knee is able to flex 90° without pain. various cen­ tres in the country are in possession of an isokinetic test apparatus. e.g. 1 military hospital, institute for sport research and training (university o f pretoria), university o f the orange free state, university o f stellenbosch and university o f port elizabeth. the cybex is an example o f an iso­ kinetic dynamometer— this apparatus is used to keep the speed at which a movement is executed constant while the resistance changes continually the muscle is under maximum load at each point in the extent o f the movement. however, when the patient is moving slower than the determined speed, no resistance is experienced. the appa­ ratus is therefore completely accom­ modating for pain and exhaustion. it is impossible for the patient to injure himself while being tested, because the less power he uses, the less the resistance. everyday activities are carried out at an angular speed o f 60 °/sec while high intensity sports activities take place at 240300q/sec. the speed at which a patient is tested, is thus determined by his requirements. the cybex is designed to test 16 movement patterns, viz: shoulder flexiontextension ab/adduction horizontal ab/adduction internal and external rota­ tion at 90° abduction r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sport if rehabl _____ programme ciba-geigy elbow flexiontextension forearm pronation&upination w rist flexionfextension radiai/ulnary deviation hip flexionfextension ab&dduction internal/external rotation knee flexion/extension ribia internal/external rotation ankle plantar/dorsiflexion w ith knee 90° flexion plantar/dorsi­ flexion with |" knee 0° flexion in/evertion. the following values can be determined for each o f t he movement patterns and are valuable in drawing up an exercise programme: 1. maximum torsion 2. total effort 3-power per kg body mass 4,extent o f movement balance between anta­ gonist muscle groups the injured limb is com­ pared to the sound limb and may not differ from it by more than 7%, or the patient is not ready to resume his spon yet. the injured limb should, however, preferably lie strengthened until it is somewhat stronger than the sound limb. an exercise programme to be follow­ ed in agymnasium under proper super­ vision is given on the basis o f the above results. the patient should always exercise within pain limits. if he experiences any pain or swelling, die resistance and/ or extent o f movement should be re­ duced. however, if no pain or swelling is experienced, resistance at which movement takes place during isotonic exercise should be progressively increased with fevery exercise session. all the muscles in an injured limb must be exercised, e.g. in knee injury' the hip flexors and extensors, aband adductors as well as the gastrocnemius and soleus should be strengthened together with the quadriceps and hampese. the hampese usually heals quicker than the q uadriceps. a flexing programme for the hampese, quadri­ ceps, groin muscles, gastrocnemius and soleus should also be given. considerable attention should be paid to proprioception and co-ordina­ tion. the patient with an injury o f the lower limb should initially exercise on a balancing board, and where the in­ jury' allows it, he should use a skipping rope. at the very end o f the rehabilita­ tion programme he could start jogging on a small trampoline. sports specific activities should also be started at the end o f the programme. when the injured limb is 20 % weaker than the sound one, the patient can start running on a straight, even surface. later, when he can achieve it without pain or swelling, he can start running faster for stretches, and later he can start 45 0 turns, and after that 900 turns and figure 8’s. when he can carry out all these activities without pain, the patient is rehabilitated as far as humanly possible and is able to resume his sport. v * i aix jiv right. the tremendous exertion which is required to measure maximum muscle load is clearly illustrated on the face o f springbok rugby captain, maas botha. alxjie left: a typical sports injury which can ikfully rehabilitated after treatment has been completed. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) international speakers for 1987 congress in this journal you will find the announcem ent of the second south african sports medicine congress to be held at the heeren gracht hotel, cape town, from april 14 to 16 1987. the preliminary programme is out­ lined, as well as some of the prominent overseas speakers that have already accepted invitations to participate in our congress. please complete the in­ tention form if you are interested in at­ tending the congress, also if you intend to read a paper on a relevant subject. there has been tremendous support — both local and overseas — for the 1987 congress in the light of the dual­ ity of the internationally renowned speakers who have already accepted invitations, the organisers have every reason to believe that the congress will be a great success. tydens die onlangse besoek van die sascv aan 'n sporttroumatologiekon gres in munchen, duitsland, was ons begroet met ongekende entoesiasme van die buiteland vir die bywoning van ons kongres cesien in die lig van die uit ers gunstige wisselkoers van die oor sese geldeenhede teenoor die suid afrikaanse rand, is suid-afrika tans 'n paradys vir die oorsese toeris kaapstad bly 'n groot aantrekkingskrag vir enige besoeker en die weer tydens april be loof ook om baie gunstig te wees — al les faktore wat 'n besoek aan kaapstad die moeite werd sal maak. die organiseerders reel ook 'n baie in teressante damesprogram wat dit die moeite werd sal maak vir afgevaardiges om hulle metgeselle saam te bring na die moederstad. die offisiele dinee gaan gepaard met 'n dansvertoning wat baie mooi aansluit by die tema van die tweede dag van die kongresverrig tinge verdere toeligting insake die kongres sal in die tydskrif verskyn en gestuur word aan diegene wat die voorneme vormpie terugstuur. i sports medicine continuing education course-provisional programme presented by the sa sports medicine association. venue: bozzoli hall, university of the witwatersrand 8 9 august 1986 friday 8 august 08.00-08.40 registration 08.40-08.50 welcome sasma president 08.50-09.10 diet and the sportsman 09.10-09.30 drugs and sport 09.30-09.50 strength and fitness for sport 09.50-10.10 energy utilisation and fluid balance in marathon running 10.10-10.30 heat injury and sport 10.30-10.50 cardiac prehabilitation 10.50-11.00 discussion 11.00-11.10 tea 11.10-11.30 cardiac rehabilitation 11.30-11.50 heart disease and the sportsman 11.50-12.10 psychiatry and sport 12.10-12.20 dlscusslon 12.20-12.40 film: heart 12.40-13.00 lunch 13.00-13.20 foot biomechanics 13.20 -13.40 ankle injuries (soft tissue) 13.40-14.00 shin splints and other shin pain 14.00-14.20 meniscal injuries 14.20-14.40 anterior cruciate instability 14.40-15.00 patbllo femoral injuries 15.00-15.10 dlscusslon .15.10-15.30 filmlnjury 15.30-15.40 tea a.g.m. sasma dinner: friday evening saturday 9 august 1986 09.00-09.20 lumbardisc pathology 09.20-09.40 shoulder injuries 09.40-10.00 elbow injuries 10.00-10.20 hand and wrist injuries 10.20-10.40 dlscusslon 10.40-10.50 tea 10.50 -11.10 sports injuries in the child 11.10-11.30 sport and the pregnant woman 11.30-11.50 physiotherapy of running injuries 11.50 -12.10 rehabilitation of knee injuries 12.10 -12.30 rehabilitation of muscle injuries 12.30-12.40 dlscusslon speakers: speakers invited to present papers include dr c noble, dr t noakes, brig e hugo and dr r morris registration: registration: r120 per person for the course send personal details and registration fees to: mrs a schuster, ro. box 55539, northlands 2116. sup p o rted by ciba-g eigy (pty) ltd august 1986 vol 1, no 2,1986 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) / m m m m u t t i , / / physiotherapy and the long-distance runner clive h, lipinski bsc (physiotherapy) who has completed both the comrades marathon and iron man triathlon. introduction: i t is not uncommon that physiotherapists are sent referrals by medical prac­ titioners asking for heat, ______ | short wave diathermy and infra red all in the same prescrip­ tion, and this being directed towards the treatm ent of a sports related in­ jury. i am fortunate in that at least 80% of my patients are sports people in this article i propose to outline the role of the sports" physiotherapist in both the treatment and management of the long-distance runner. my definition of a "sports" physiothe­ rapist is one that has an adequate knowledge of the sport ia training and competing as well as adequate equip­ ment for both the acute management of the injury and for the later rehabili­ tation of the sportsman back to com­ petitive sport. role of the sports physiotherapist and the bong distance runner often the first person the runner consults regarding his injury is the physiotherapist. i feel there is a varie­ ty of reasons for this: firstly, a fellow runner may have been treated by the physiotherapist and recommended him, and secondly, the runner is afraid that his doctor does not see too many athletes and may tell him to rest. it is thus essential that the physio­ therapist can accurately assess the run­ ners problem, after obtaining permis­ sion from the runners doctor. the run­ ner is liable to exaggerate the symp­ toms and thus, both'accurate joint and soft tissue examinations must be done by the physiotherapist. lets now look at the complete treat­ ment given to the long distance runner, presuming the diagnosis has already been established. £ 1. advice (general) more often than not the runner has been given no advice by the medical practitioner re­ garding the injury. he may, for exam­ ple, know that he has a torn hamstring but that is about all. it is the physiothera­ pist's responsibility to f r n inform the runner about f the mechanism of the in psjf.#r jury, the methods of self treatment of the injury eg. ice packs, and the preventative mea­ sures that can be used. it may also be necessary here to ad­ vise the runner about the correct way to stretch. it may also be necessary to inform him about correct strengthen­ ing to facilitate the injury healing and to prevent a recurrence i also find it advanta­ geous to watch the runner in motion, both with and without his shoes on. "it will show whether the runner has excessive subtalar pronation or supination." 2. foot and shoe assessment it is also essential that the physio­ therapist be able to find the neutral po­ sition of the runners foot in weight bearing and then examine for ab­ normalities i also find it advantageous to watch the runner in motion, both with and without his shoes on. 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) t will show whether the runner has excessive sub­ talar pronation or supina­ tion. i also use it to assess the medial rotation of the tibia in midstance phase to g e th e r with patella displacement shoe assessment forms a large part o f the "complete treatm ent pro­ gramme". often the runner is about to embark on buying a new pair of shoes (average cost r135) and because of his previous and most probably present in­ jury wants to buy the shoe that is most correct for his particular need. it is essential that the physiotherapist examine older pairs o f shoes to gauge running patterns. the shoe that the physiotherapist prescribes or advises to the runner must be correct for both the runner's style weight; distance that he wants to run and terrain that he wants to run on. training guidance the greatest fear is the severity of the injury. he is never quite sure when to resume training, how much he should be doing when he does resume training and on what surface he should run on. it is thus important that the physio­ therapist understand the nature and biomechanics of the injury so that cor­ rect advice as to training can be given. the physiotherapist should take into ac­ count the hardness of the terrain, the camber of the road and the topo­ graphy before setting out a training programme when treating south african long­ distance runners that are comrades marathon orientated, their injuries tend to be of severe overuse the physiotherapist treating the run­ ner must know how to reduce the run­ ner's distance to assist the injury heal­ ing, but at the same time must bear in mind the fact that the runner has to have completed sufficiently long runs so that he can complete the race it must also be remembered that the runner who attempts the comrades marathon is a very serious, committed person. those at the back have all kinds of things on their minds. they dream of the houses they're building and the fight they had with their wives—anything to take their minds off the agony they're going through. but some of the front runners are a pretty odd lot too. i guess we re all a little mad: brucefordyce. august 1986 vol 1, no 2,1986 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a sudden severe decrease in running mileage could affect his whole psycho­ logical approach to the race. when a runner does need to stop running completely, eg. in the case of a stress fracture, it is necessary for the physiotherapist to recommend alternative methods of training. i usual­ ly suggest the runner train in a swim­ ming pool by suspending himself with a lifejacket or such and then tun­ ing on the spot, his feet o ff the pool surface the buoyancy of the water supports the stress fracture and the action simulates normal training. i also put the runner on a weight training programme that does not interfere with the injury. on the spot assessment when dealing with highly com ­ petitive long-distance runners, their in­ jury may sometimes only be elicited while running. thus it is very difficult to accurately find the site of injury. at this stage the physiotherapist should go out and run with the runner so as to accurately locate the injury site as well as assess the movement that is causing pain. if the above is not possi­ ble, i usually advise the runner to go out on a gentle run and mark the pain­ ful area with a pen. i find it important that he does not palpate the area of pain, but simply marks it wi^h his pen. he should also note when the pain occurs and what increased or eased it. all this assists the physiotherapist in a more accurate as­ sessment and treatm ent of the injury. treatment of the injury as can be noted from steps one to four there has been no mention of the physical treatm ent of the injury. it is only now that the physical "hands on" treatment of the injury should begin. i believe that although the diagnosis has been established by the doctor, the actual modalities and methods of treatment should be left to the physiotherapist. machinery and methods of dealing with running injuries and sports injuries as a whole are dynamic machines such as interferential therapy; curapuls (pulsed short wave .diathermy); dia aynamic current and infra red laser are £ ® more modem modalities available ro tne sports physiotherapists together with the more established ultra sonic therapy. i i ^ u,|p|tient such as the orthotron r isokinetic strengthening, and allows.for a mixture between l*wkinet|c and isotonic strengthening, uinrwvs e jt ment of choice has become wdrous, deep cross frictions of the in~ as opposed to a gen­ tle relaxing massage. w s t 1986 vol 1, no 2,1986 when treating running injuries, the acute management by the physio­ therapist involves the stopping of bleeding into the affected area, the reduction of inflammation and or oedema and pain relief this is usually achieved by electrotherapy modalities, anti-gravity positioning and home advice once the injury has passed the acute phase, the physiotherapist must now examine whether there has been loss of strength in the limb due to the in­ jury. often an injury to the soft tissues leaves the runner with less flexibility and this the physiotherapist must as­ sess and correct where necessary. the progression of the runner back to full training during the injury phase must be gradual and well monitored by the physiotherapist. although i usually completely curtail training only in three instances — namely — stress fractures, tendonitis with crepitus and severe muscle rup­ tures, i do however alter the runner's programme. this usually involves a decrease in dis­ tance, altering the pace, and a change of running environment and some­ times a change of terrain. i find that keeping the runner mobile throughout his injury, helps him cope physiologically and also assists me in my subjective ex am in a tio n d u rin g th e follow ing treatments. conclusion: no longer does a physiotherapist simply "rub" away the sports injury. the approach towards the management and treatm ent of running injuries has become dynamic and aggressive. 19r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) he argument t for a "running addiction” the biochemical argument this argument contends that run­ ning is addictive because it stimulates the release of certain hormones inside the brain, the endorphins or enkepha­ lins, which give the runner a pleasur­ able feeling while he is jogging — the so-called runner's high (callen, 1983), the brain then becomes dependent on these pleasure-producing substances just as it does to other potentially addictive substances like heroin, co­ caine, or morphine. but, like all addic­ tions, the euphoric feelings can only be maintained if the dosage (i.e. running distance) is continually increased. the psychological argument other writers have noted that the withdrawal symptoms described by runners who are forced to stop running for a period of time are mainly of a psy­ chological, rather than a physical nature. the psychological withdrawal symptoms that they describe include guilt, irritability, anxiety, tension, rest­ lessness and depression. these writers also note that runners like myself tend to lay rather too much emphasis on the mental benefits of running and sug­ gest that this may indicate that such addicted runners use their running to cope with major underlying psycho­ logical problems. victor altshul (1981) suggests that if jogging is indeed able to mask anxiety and depression, as these runners testify, albeit for relative­ ly short periods, then it follows that many people with these psychological abnormalities will use running as an effective and cheap home-remedy. like sacks, altshul also notes that compulsive running frequently starts in response to a major emotional up­ heaval. "my impression... is that if... a lean athletic man is consciously or uncons­ ciously contemplating divorce, there is at least a 75% chance that he is or will be a compulsive runner. thus, i would claim not that running causes divorce, but rather that divorce, among other forms of human misery, causes run­ ning." a number of abnormal psychological states possibly present in addicted run­ ners are described below: i) primary affective disorder apparent evidence for the postulate that running m ight attract persons more likely to suffer from anxiety or depression comes from a study by a new york physician, dr edward colt and his colleagues (1981). in a group of sixty one runners who were participating primarily ip a study of their physiology not their psychology, he found a high incidence of what is termed “primary affective disorder": persons with this condition suffer from more anxiety and depression than is considered nor­ mal, and frequently require psychiatric assistance, including psychotherapy. am ongst the group were some elite athletes who also showed this disorder. colt concludes that this data indeed suggest that running may be particu­ larly rewarding for those runners with affective disorders. he also noted that some runners said they became "revved up" after very intensive train­ ing sessions and these workouts were frequently followed by insomnia. these symptoms, which i have certainly ex­ perienced, are said to indicate "hypoma nia". one question that colt suggests needs to be answered is what happens to competitive athletes when they re­ tire from competition’ do they be­ come depressed? if so he asks, could this explain those suicides that occur in retired athletes7 ii) the athletic neurotic psychological dependence on run­ ning may occur not only because it helps control primary affective disord­ ers, but also because it may provide an essential coping mechanism for those who have a neurotic fear of illness. some indication for this was first provided by a leeds psychiatrist. dr crawford little (1969), in a paper that went largely unnoticed prior to the cur­ rent interest in running addiction. little noted that amongst patients referred to him for the treatm ent of neurosis, 42% were completely unath letic; they showed not the slightest in­ terest in any form of physical activity. however, 39% were the precise oppo­ site. these "athletic neurotics" seemed to over-value the importance of health and fitness and revealed an "inordinate pride" in their previous sickness-free progress through life and in their ex­ cess physical stamina, strength or skill. subsequently, little has concluded (1981) that athletic neurosis is not a trivial, short-lived illness. he suggests that while excessive athleticism is not in itself neurotic, because it does not cause any suffering in either the sub­ ject or his family, it can place the sub­ ject in a vulnerable pre-neurotic state, leading to manifest neurosis in the event of an appropriate threat. despite this, little considers that the overall benefits o f the exercise movement of the 1980s far outweigh the small danger that some athletic neurotics will be produced. since re-reading little's article, i have become more aware of the athletic neurotics. one recent example was the 45-year-old man who wanted to know whether or not he should take anabolic steroids to improve his muscle bulk and strength. my suggestion that, at his age, he shouldn't still be so vain was quite clearly-inappropriate, as his ath­ letic neurosis demanded that he go to inordinate ends to insure that he did not become weak, iii) the obsessive-compulsive athlete in its extreme form, "obsessive compulsive" behaviour is characterised by a rigid, intensely focused attitude; preoccupation with technical detail; over-reliance on intellectuality with a loss of emotional responsiveness,wor­ ry and marked self-criticism; over­ concern for moral and professional responsibility, with emphasis on what should be done; and constant routine activity performed with the use of a schedule and checklists. running is attractive to the obses­ sive-compulsive because it provides a rigidly defined goal (such as running the comrades marathon) which justi. fies a constant, routine activity (train­ ing) and preoccupation with detail (training methods, diet, shoes, reading this book, etc). (to be cont. in vol. 1 no. 3 1986) s u id -a frik a a n se s p o rtg e n e e sk u n d e vereniging a p p l ic a t io n f o r m a a n s o e k v o r m so u th a frican s p o rts m edicine a ss o c ia tio n full m em b er/v o ile lid r 25 s tu d e n t m e m b e r/s tu d e n te -lid r5 tel no/tel n r ................masa no/mvsa n r . f u ll m e m b e r . medical practitioners who are members of m.a.s.a. v o ile lid: medlese praktisyns wat lede van die m.v.s.a. is . s tu d e n t m e m b e r medical stu­ dents in clin ical years. s tu d e n te -le d e : mediese studente in nul klinlese jare. a p p li­ cations for membership of sasma should be sent to. t h e secretary. sasma. 1131 cburcn st. hat field, pretoria. 0083. cheques to accompany membership form. august 1986 vol 1, no 2,19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research 1 sajsm vol. 30 no. 1 2018 male academy rugby union student-athletes in-season physical anthropometrical and physical performance changes, and comparisons with available data n rishiraj1, phd, atc; b niven2, msc 1 actin health & rehabilitation inc., vancouver, bc, canada 2 department of mathematics & statistics, university of otago, dunedin, new zealand corresponding author: n rishiraj (nrishiraj@actinhealth.com) since 1871, rugby union (ru),15-a-side, has maintained a long and distinguished history, including being recognised as a summer olympic games medal sport in 1900, 1908, 1920, and 1924. the men’s ru joined the professional ranks in 1995 and is now played in argentina, france, japan, oceania, south africa, and the united kingdom. on ru gaining professional status, the physiological demands of the game have increased, specifically the greater number of collisions, passes, rucks, tackles, tries, and ball-in-play time/work-rest ratio.[1] to overcome the physiological ru game demands, prevention of injury, allowing the possibility of advancing to the professional level of play, and to enhance career longevity, ru players must start at a young age to adapt their physical stature and metabolic systems. however, there is sparse anthropometrical and physical performance data available on developing ru players. there are also no anthropometrical and/or physical performance data available on ru academy student-athletes during in-season ru competition. this information is important as it has been shown that approximately 30% of the players representing a junior national ru team advance to a senior national team.[2] the purpose of this research was to investigate anthropometrical and physical performance changes in male new zealand academy student-athletes (nzasa), participating in the nz otago rugby union (orfu) premier league, over 31 weeks and, where possible, compare collected data with the published data from international academy ru athletes. it is hypothesised is that nzasa anthropometrical and physical performance variables would show slight improvements over the 31-week competition season which would be similar to preand post-training physical performance characteristics of academy ru athletes competing in different countries. methods experimental design the orfu recruited 20 student-athletes from across the nation. ethical approval was obtained from the institutional ethics committee and an informed consent was received from each orfu student-athlete. to address any potential medical concern(s), injury history and medical information was reviewed with the respective player and the orfu academy manager. all nzasa were actively participating in orfu premier division teams. the nzasa trained up to 25 hours per week, with an additional 15 hours scheduled for team practices and game play (table 1). testing sessions were periodised for the start of the season (week 1), in-season (week 18), and preplayoffs (week 31) to ensure anthropometrical and physical performance data were collected from the maximum number of nzasa. all anaerobic capacity and sprint testing was completed on an indoor balsam probounce sand-filled synthetic carpet surface. subjects and anthropometrical measures the age range of the 20 nzasa was 19 to 21 years and the pooled (11 forwards and 9 backs) mean body weight was 92.1 kg with a standard deviation of  11.6 kg. the pooled mean of the seven skinfold sites[3] was 91.3 cm  38.4 cm. detailed body weight and skinfold data are presented in table 2. background: physical performance demands of the rugby union (ru) game have increased over the past two decades. however, there are little data on these variables concentrating on developing ru players (student-athletes) over a competitive season. objectives: to investigate the potential enhancement of two physical anthropometrical and nine physical performance variables of male new zealand ru academy student-athletes over a competitive season and compare with similar published data. methods: twenty student-athletes were recruited to the otago rugby football union (orfu) two-year academy programme. each week the student-athletes engaged in 25 hours of strength and conditioning training and participated in 15 hours of on-field rugby training with their respective orfu premier league team. assessments sessions were scheduled for the start of the season, in-season, and pre-playoffs (week 31). results: mean data from 20 student-athletes demonstrated a trivial effect size (es) increase in body weight and skinfold measurements, while a paired t-test (p<0.05) resulted in concurrent significant improvements in lower-body power (es = large), acceleration (es = large), speed (10 m sprint, es = small, 40 m sprint, es = small), and upper body strength (bench press, es = large and bench pull, es = small). a nonsignificant physical performance improvement, with trivial es difference, was also noted in anaerobic endurance performance. conclusion: based on these data significant physical performance enhancements were observed during in-season premier league competition while limiting fatigue and overtraining. keywords: aerobic, anaerobic, athlete development, skinfolds, strength s afr j sports med 2018;30:1-5. doi: 10.17159/2078-516x/2018/v30i1a5577 mailto:nrishiraj@actinhealth.com http://dx.doi.org/10.17159/2078-516x/2018/v30i1a5577 original research sajsm vol. 30 no. 1 2018 2 physical performance measures lower body power: vertical jump/countermovement jump testing procedures were followed from previous validated work[4] and data were collected using the vertec (sports imports, hilliard, oh, usa) measurement device. the coefficient of variance (cv)/reliability has been documented to be 5.3%.[4] acceleration and speed: 5 m, 10 m, and 40 m sprint nzasa started the sprint on their own time, after receiving the command from the tester. the timed run commenced from a standing start and subjects sprinted through the 5 m, 10 m, and 40 m timing gates, and only slowed down after passing the final timing gates. sprint elapsed time (in seconds) was recorded using the swift electronic lighting system, accuracy of 1/100th of a second (swift performance equipment, nsw, australia). the timing gates were set at a height of 75cm. subjects performed three trials with a one minute rest between trials. the cv under similar protocols has been shown to be 1.9–2.0%.[4] upper body strength: bench press testing procedures were followed from previous published work and the cv has been established to be 1.5%.[4] upper body strength: bench pull the bench pull is used to assess the strength of the antagonistic muscles to the bench press. an olympic barbell and plates were used for testing. the start position consisted of the nzasa lying prone on a bench with the chin touching the bench throughout the whole movement. the nzasa then pulled the barbell upwards until it reached the underside of the bench. a series of maximal lift attempts were then performed until a 1rm (in kilograms) was obtained. a similar rowing test reported a cv of 2.3%.[4] anaerobic endurance: phosphate decrement test (pdt), pdt mean, percent fatigue, and percent effort nzasa performed 10 x 40 m sprints, every 30 seconds. a cone was placed 20 m past each end of the 40 m sprint timing gates and nzasa were instructed to jog/walk around a cone during the 30 seconds recovery duration, but to return to the respective starting gate before the 30 seconds recovery period had elapsed. the test started from a standing start on the command for the tester. as per the acceleration and speed test, sprint elapsed time (seconds) was recorded using the swift electronic lighting system after each 40 m sprint. the timing gates were set at a height of 75 cm. a comparable repeat sprint evaluation reported a cv of 1.9%.[4] nzasa performed the pdt once (10 x 40 m sprints). data were expressed as follows:  pdt mean  percent fatigue provided data on the fatigue rate or performance ‘drop-off’ over the total 400 m (10 x 40 m sprints) distance, and  percent effort involves comparing the fastest pdt sprint repeat time with the fastest 40 m acceleration-speed result and allows for analysis of the effort made by the respective student-athlete during the 10 x 40 m sprint repeats. an aerobic capacity test (1500 m run on an outdoor rubberised 400 m track) was also scheduled over the three testing sessions; however, poor climate conditions negated various testing sessions. statistical analysis analysis of the changes in body weight, skinfold measurement, and physical performance levels of the nzasa over a 31-week period (week 1 and week 31) were completed using descriptive statistics (mean, sd, minimum and maximum range, and confidence intervals). paired t-tests (week 1 and week 31) were performed to detect possible anthropometrical and physical performance changes over the 31-week in-season premier league competition, with significance being determined at the p< 0.05 level. furthermore, the magnitude of the differences between the means was described using cohen’s effect sizes (es) with the corresponding descriptors, trivial = 0 0.19, small = 0.20 0.49, medium = 0.50 0.79, and large = >0.80.[5] data analysis was performed using spss for windows version 13.0, spss inc, chicago, ill, usa. results anthropometrical characteristics body weight and skinfolds resulted in trivial increases of 0.8% and 7.4%, respectively, over the 31-week premier league competition (table 2). physical performance characteristics significant physical performance enhancement was achieved for six physical performance variables, ranging from 0.9% to 14.6%, with a large es differences being noted for the cmj/vj, 5 m sprint and the bench press. significant but small es table 1. new zealand academy student athlete weekly game, practice, and training schedule over the competitive season, weeks 1 to 31 sunday monday tuesday wednesday thursday friday saturday am: recovery session* pm: rest am: weight training pm: aerobic/ anaerobic training am: core & flexibility training pm: team practice am: weight training noon: individual specific training pm: speed and agility training am: core & flexibility training pm: team practice am: activation session† pm: rest game day *recovery session consisted of aerobic, stretching, and massage (latter, budget dependant) followed by a team brunch. †activation session involved aerobic and flexibility activities for 30-45 minutes duration. original research 3 sajsm vol. 30 no. 1 2018 table 2. new zealand academy student-athlete physical and performance characteristics over the competitive season and comparable data mean ± sd (% change)‡ range 95% confidence interval cohen effect size & (descriptor)[9] english academy u21 ru§[15] south african u20 ru¶|[16] min max lower upper body weight (kg) week 1 92.1  11.6 67.3 112.3 86.6 97.5 0.14 (trivial) 98.3 ± 10.4 92.3 ± 8.5 week 31 92.8 ± 12.6 (0.8) 64.6 115.7 86.9 98.7 skinfolds (mm)† week 1 91.3 ± 38.4 58.50 188.0 73.3 109.3 0.18 (trivial) 105.3 ± 35.4 week 31 98.1 ± 35.6 (7.4) 52.5 190.0 81.4 114.7 vertical jump / counter movement jump (cm)* week 1 55.1 ± 7.4 44.0 75.0 51.5 58.6 0.87 (large) 47.1  3.6 week 31 61.4 ± 7.1 (11.5) 52.0 84.0 58.1 64.7 5 meter sprint (s)* week 1 1.05 ± 0.04 1.00 1.20 1.03 1.08 1.10 (large) 1.07 ± 0.07 week 31 1.00 ± 0.05 (-4.4) 0.90 1.20 0.98 1.04 10 meter sprint (s)* week 1 1.78 ± 0.07 1.70 2.00 1.75 1.83 0.71 (medium) 1.79 ± 0.10 1.73 ± 0.10 week 31 1.73 ± 0.07 (-2.8) 1.60 1.90 1.70 1.77 40 meter sprint (s)* week 1 5.49 ± 0.35 5.10 6.60 5.33 5.66 0.43 (small) 5.43 ± 0.21 5.23 ± 0.30 week 31 5.36 ± 0.24 (-2.3) 5.00 5.80 5.25 5.48 bench press (kg; 1rm)* week 1 103.6 ± 19.4 60.0 139.8 94.5 112.7 0.80 (large) 108.2 ± 14.1 135 ± 22.0 week 31 118.8 ± 18.7 (14.6) 62.0 145.0 110.0 127.5 bench pull (kg; 1rm)* week 1 87.9 ± 10.3 65.0 103.4 83.1 92.7 0.47 (small) 96.8 ± 8.2 week 31 92.7 ± 10.2 (5.4) 67.0 108.9 88.0 97.5 pdt-mean (sec) week 1 5.96 ± 0.29 5.50 6.60 5.83 6.09 0.17 (trivial) week 31 5.91 ± 0.30 (-0.9) 5.40 6.60 5.77 6.05 pdt-fatigue (%) week 1 12.4 ± 4.90 7.50 27.0 10.1 14.7 0.05 (trivial) week 31 12.1±6.01 (-2.3) 6.40 25.6 9.32 14.9 pdt-effort (%) week 1 93.5 ± 4.0 84.2 98.0 91.6 95.4 0.14 (trivial) week 31 92.8±5.8 (-0.7) 79.1 99.5 90.1 95.6 *significant performance enhancement between week 1 (season-start) and week 31 (pre-play-offs) testing sessions for: vertical jump (p = 0.001); 5 meter sprint (p =0.014); 10 meter sprint (p = 0.031); 40 meter sprint (p = 0.029); bench press (p = 0.001); bench pull (p = 0.003). testing sessions in week 1 occurred in march at the start of the season. testing sessions in week 31 occurred in october during pre-playoffs. †skinfolds: sum of seven skinfolds; an experienced nutritionist performed all skinfold tests following previous published methods. measurements were taken using calibrated harpenden skinfold callipers at the following sites: abdomen, chest, midaxillary, quadriceps, subscapular, suprailiac, and triceps.[3] ‡percent (%) change from week 1 (season-start) to week 21 (pre-playoffs). §data collected from fifteen u21 male english academy ru players; playing position not specified. authors used sum of eight site skinfolds (biceps, triceps, subscapular, suprailliac, abdominal, supraspinale, front thigh and medial calf). data collected at ‘season-start’ (june) after a six week off-season training period.[15] ¶|data collection over 13 years from a total of 453 (forwards = 256 and backs = 197) players representing junior (u20) south african national team. mean data of the respective duration presented. data collected at the ‘season-start’, december/january of respective season.[16] body mass was collected using a calibrated electronic scale (a & d engineering inc.). 1rm, one repetition maximum; ru, rugby union; rl, rugby league; pdt, phosphate decrement test original research sajsm vol. 30 no. 1 2018 4 differences were found for the 10 m sprint and bench pull physical performance variables (table 2). discussion this study investigated the anthropometrical and physical performance adaptations of nzasa due to the lack of available data on developing ru student-athletes over a 31week premier league competition. during the 31-week season body weight of nzasa increased by 0.8% with a concurrent increase in skinfolds by 7.4%. the increase in body weight is consistent with published data from australian professional male ru players that reported annual body weight increases of 0.8% to 2.1%.[6] however, the australian professional male ru players experienced an annual decrease in skinfolds of between 3.9% to 7.2%.[6] the increase in body weight experienced by the nzasa is also supported by available literature that states that when athletes reach their adult height, their body weight continues to increase, with a simultaneous increase in lean body mass, due to continued resistance training and adequate nutrition.[7, 8] although the higher skinfold level may offer some protection during collisions, published literature has expressed concern regarding excessive body fat as being “dead weight” and hindering a player’s work rate and performance.[1] however, even though body weight and skinfolds in the present study continued to increase, improvement was evident in all nine physical performance variables, with six variables showing significant improvements and of these six variables, a large es difference was noted for three physical performance variables. these results would suggest that the nzasa had achieved a relatively high level of mesomorphy; an anthropometrical characteristic deemed important for elite physiological performance and good tackling ability.[9] the mesomorphy status of the nzasa gains credibility when compared with published data from similar age ru athletes. the nzasa weighed 6.2 kg less and had a 14 mm lower skinfold measurements compared to english academy u21 ru (earu) athletes[10] and were of similar body weight as the south african u20 ru (saru) athletes[11] (table 2). the lower body power result achieved on week 1 by the nzasa was superior by 8 cm compared to data from the earu[10] athletes. over the 31-week premier league play the nzasa further recorded 11.5% significant (es = large) lower body power performance improvement. this increase in lower body power is deemed important as previously published literature from the rugby league (rl) has illustrated that the higher lower body power assists with the generation of greater leg drive to counter the forward progression of the opposing player during tackling.[9] the enhanced lower body power/leg drive generation could also have contributed to the significant improvement in acceleration (5 m) and 10 m and 40 m speed variables in nzasa over weeks 1-31. since sprinting requires high force production[12] nzasa data are consistent with published literature, which have illustrated a strong correlation between vj/cmj, acceleration and sprint speed over various distances (power to weight ratio).[13] as such, nzasa must have developed sufficient power output to overcome the increases in body weight and skinfolds thereby achieving significant enhancement in acceleration (large es difference) and speed variables over the 31-week ru season. nzasa acceleration performance at the start of the season was slower than that of the earu athletes;[10] however, the latter athletes had completed six weeks of training prior to their acceleration performance evaluation. the 10 m sprint time of the nzasa at week 1 was marginally faster than that of the earu[10] athletes, but slower when compared to the saru[11] athletes. however, it should be noted that data from the saru athletes were recorded after the completion of one or more annual periodised training cycle(s). data from the nzasa 40 m sprint times were also slower than that from the earu[10] and the saru[11] athletes respectively. however, as stated above, the faster earu and saru sprint times could be the result of the longer respective training durations. over the 31-week ru season, the nzasa recorded 14.6% and 5.4% upper body strength gains in the 1rm bench press and bench pull tests respectively. the relatively small increases in strength measures are consistent with previously published data from different football codes. for example, english rl super league academy u20 athletes demonstrated a small increase in strength,[7] while the american collegiate north american football players either recorded a 4% increase, no significant change, or a loss in strength.[14] several other authors have attributed the low strength gains to increased capacity of concurrent aerobic and/or reduced volume of resistance training, and/or fatigue due to overtraining.[15] it is noted that the nzasa upper body strength gains, especially for the irm bench press, were much higher than those reported in the literature and that these higher upper body strength gains could be attributed to the cumulative training volume and stimulus,[16] and/or the cumulative effect of improved professionalism of developing rugby players, increased emphasis on physical enhancement strategies and decreased injury risk/rates, which allowed for increased resistance training capacity/volumes.[8] also, the structured and supervised training sessions with continued feedback may have led to increased adherence/compliance of the nzasa, which allowed for the attainment of higher training loads and could have attributed to enhancing the nzasa ‘training age’. according to published data, the enhancement in ‘training age’ leads to improved movement patterns, increased synchronisation of motor units and concurrent decreased antagonist muscle firing, as well as decreased inhibitory feedback mechanism all of which contribute to the production of high levels of force.[16] the phosphate decrement test (pdt) /repeated sprint test is perceived as being important in evaluating the anaerobic system required for delivering energy during a rugby competition, especially since the intensity of the ru game has increased with the inauguration of the professional super 12 ru competition.[1] however, there is a lack of anaerobic data on ru players reported in the literature.[1] during the nzasa 31-week premier league season training duration mean sprint times over the ten repetitions of 40 m (pdt-mean) improved by 0.9%, with a concurrent lower fatigue original research 5 sajsm vol. 30 no. 1 2018 level (pdt-fatigue) by 2.3% and a 0.7% decrease in effort (pdt-effort) /increased efficiency of the anaerobic system. these results could be a result of an improvement in anaerobic threshold, specifically a decrease in muscle ph, phosphocreatine, atp activation of anaerobic glycolysis due to a significant involvement of aerobic metabolism and the enhancement of the vo2max and aerobic enzyme activity.[17] these authors’ hypothesis was partially correct as nzasa physical performance results at the start of the season were either inferior or superior compared with respective ru athletes of similar age groups from other nations. after 31weeks, compared to erua and saru athletes, nzasa weighed less, had lower skinfold measurements, and were, generally, faster and stronger while being ‘fatigue-resistant’ and required less effort to attain positive physical performance results during high-intensity activity. conclusion this study is the first to provide evidence of large to small physical performance enhancement in academy studentathletes over a 31-week premier ru league season with trivial increases in body weight and skinfold measurements yet without the detrimental effects of fatigue/overtraining. as such, team staff (coaches, sports medicine and sports science professionals) should appreciate that gains in anthropometrical characteristics do not necessarily lead to negative physical performance (acceleration, anaerobic endurance/threshold, lower body power, speed, and/or upper body strength) variables. this data will hopefully assist respective staff of tier 2 ru nations (as defined by the international rugby board/world ruby) a greater understanding regarding the anthropometrical and physical performance demands required to complete against elite/tier 1 ru nations. disclosure statement: none of the authors have/had a financial or personal conflict of interest with any person(s) and/or organisation(s) and did not influence the data/work presented in this paper. references 1. duthie g, pyne d, hooper s. applied physiology and game analysis of rugby union. sports med 2003;33(13):973-991. [doi: 10.2165/00007256-200333130-00003] 2. parker za. factors associated with success in south african rugby union. cape town: university of cape town, 2013. url: https://open.uct.ac.za/handle/11427/2760 3. eston rg, hawes mr, martin ad, et al. human body composition. in: eston r, reilly t, eds. kinanthropometry and exercise physiology laboratory manual: tests, procedures and data. vol. 1 anthropometry. 3rd ed. london: routledge; 2009: 3-53. 4. tanner r, gore cj, eds. physiological tests for elite athletes. australian institute of sport. 2nd ed. 2013; chapter 11: 167-197. 5. cohen j. a power primer. psychol bull 1992;112(1):155-159. [pmid:19565683] 6. appleby b, newton ru, cormie p. changes in strength over a 2-year period in professional rugby union players. j strength cond res 2012;26(9):2538-2546. [doi: 10.1519/jsc.0b013e31823f8b86] 7. till k, tester e, jones b, et al. anthropometric and physical characteristics of english academy rugby league players. j strength cond res 2014;28(2):319-327. [doi: 10.1519/jsc.0b013e3182a73c0e] 8. smart dj, hopkinswg, gillnd. difference and changes in the physical characteristics of professional and amateur rugby union players. j strength cond res 2013;27(11):3033–3044. [doi: 10.1519/jsc.0b013e31828c26d3] 9. vaz l, vasilica i, carreras d,et al. physical fitness profiles of elite under-19 rugby union players. j sports med phys fitness 2016;56(4):415-421. [pmid: 25651896] 10. darrall-jones jd, jones b, till k. anthropometric and physical profiles of english academy rugby union players. j strength cond res 2015;29(8):2086-2096. [doi: 10.1519/jsc.0000000000000872] 11. lombard wp, durandt jj, masimla h, et al. changes in body size and physical characteristics of south african under-20 rugby union players over a 13-year period. j strength cond res 2015;29(4):980-988. [doi: 10.1519/jsc.0000000000000724] 12. mero a, luhtanen p, vitasalo jt, et al. relationships between the maximal running velocity, muscle fiber characteristics, force production and force relaxation of sprinters. scand j sports sci 1981;3(1):16-22. 13. cronin jb, hansen kt. strength and power predictors of sports speed. j strength cond res 2005;19(2):349-357. [doi: 10.1519/14323.1] 14. hoffman jr, kang j. strength changes during an in-season resistance-training program for football. j strength cond res 2003;17(1):109–114. [pmid: 12580665] 15. baker dg. 10-year changes in upper body strength and power in elite professional rugby league players--the effect of training age, stage, and content. j strength cond res 2013;27(2):285-292. [doi: 10.1519/jsc.0b013e318270fc6b]. 16. argus ck, gill nd, keogh jw. characterization of the differences in strength and power between different levels of competition in rugby union athletes. j strength cond res 2012;26(10):2698-2704. [doi: 10.1519/jsc.0b013e318241382a] 17. spencer m, bishop d, dawson b, et al. physiological and metabolic responses of repeated-sprint activities: specific to field-based team sports. sports med 2005;35(12):1025–1044. [pmid: 16336007] original research 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license the effect of the contract-relax-agonist-contract (crac) stretch of hamstrings on range of motion, sprint and agility performance in moderately active males: a randomised control trial t burgess, phd1; t vadachalam, msc (sports physiotherapy)1; k buchholtz, mphil (sports physiotherapy)2; j jelsma, phd1 1division of physiotherapy, department of health and rehabilitation sciences, faculty of health sciences, university of cape town, cape town, south africa 2division of exercise science and sports medicine, department of human anatomy, faculty of health sciences, university of cape town, cape town, south africa corresponding author: t burgess (theresa.burgess@uct.ac.za) hamstring strains are among the most common sports-related injuries, and account for a significant number of missed competitions for elite athletes in a variety of sporting codes.[1] there is a high rate of hamstring strain reoccurrences which impacts on the athlete’s return-to-play; and indicates the persistent nature of the injury.[1] this is not surprising as, from an anatomical and biomechanical perspective, the hamstring muscle complex is at an increased risk of injury due to its biarticular structure and its functions as a hip extensor and knee flexor.[2] it is particularly vulnerable during sporting activities that involve sudden acceleration/deceleration and jumping, such as field hockey and soccer.[3] stretching has been advocated as a method of improving or maintaining flexibility and has been used prophylactically in many sporting codes to prevent muscle strains. this is despite the lack of clear evidence for the proposed benefits of improved flexibility in injury reduction.[4] different stretching techniques, such as static, ballistic and proprioceptive neuromuscular facilitation (pnf), have been used.[5] the concept of pnf stretching is based on neurophysiological principles. the methods include reciprocal and autogenic inhibition through manual contact, diagonal and spiral movement of the limb, and normal timing. these methods facilitate sensory input, functional muscle contraction (including synergist overflow), sequential contraction and coordinated movement, respectively.[6] there are several pnf stretching techniques which may be utilised, including the contract-relax-agonist-contract method (crac) which combines different elements of a stretch.[7] in a crac stretch, the antagonists (e.g. hamstrings) are first passively stretched, followed by a six to 15 second isometric contraction against resistance at the point of limitation. this contraction is immediately followed by a six to 15 second concentric contraction of the agonists (e.g. quadriceps). this is followed by 20 seconds of rest before the cycle is repeated four to five times. the use of the isometric contraction of the antagonists (hamstrings) at the end of the range serves a dual purpose: the fatigue of fast-twitch fibres and sensory receptor stimulation. firstly, fatigue of the fast-twitch fibres reduces their capacity for maximum force production when exposed to subsequent stretch resistance.[3] isometric contraction induces post-isometric relaxation in the muscle, which results in reduced muscle tone. post-isometric relaxation has been defined as the 15 second refractory period after isometric contraction during which the new point of resistance of a joint or muscle may be achieved more easily.[8] secondly, sensory receptor stimulation occurs due to the effect of isometric contraction on the golgi tendon organs (gto) and muscle spindle fibres. the isometric contraction of a stretched muscle serves to pre-tension the gto.[9] the increase in tension causes inhibition of the contracting antagonist, while there is simultaneous stimulation of the agonist muscle (quadriceps) by the process of autogenic inhibition.[9] during the transient period of decreased hamstring sensitivity and excitability caused by autogenic inhibition, post-isometric relaxation and h-reflex inhibition, the concentric quadriceps contraction is initiated. although hamstring electromyographic (emg) activity may increase, smooth knee joint motion should occur during the quadriceps contraction as the hamstrings are background: although stretching is done routinely to prevent injury during explosive sport activities, there is some concern that effective stretching might negatively impact on performance. objective: this study’s main objective was to investigate the impact of a specific stretch, the contract-relax-agonist-contract (crac) stretch, in which the muscle to be stretched, namely, the hamstrings, is actively contracted and then relaxed. this is followed by the antagonist muscle (the quadriceps) contracting. secondly, the impact of the stretch on performance was examined. methods: a randomised control trial was used. forty healthy active males between 21 and 35 years old were assigned to either receive three repetitions of crac or rest. hamstring flexibility and the illinois agility test were the primary outcome measures. results: the intervention was effective in improving hamstring flexibility by 37% immediately post-application and was maintained for eight minutes thereafter. it had no significant effect on agility or sprint times. conclusion: crac, when applied to stretch the hamstring muscles of active males, resulted in a large increase of active knee extension range of motion, without decreasing performance. therefore, crac appears to be a safe and effective method of increasing the length of the hamstrings pre-sport activity and should be utilised by sports physiotherapists if deemed necessary. it was also shown to be beneficial following the initial assessment. keywords: sport performance, proprioceptive neuromuscular facilitation, pnf, flexibility, knee s afr j sports med 2019;31:1-5. doi: 10.17159/2078-516x/2019/v31i1a6091 mailto:theresa.burgess@uct.ac.za http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6091 https://orcid.org/0000-0001-9796-2182 https://orcid.org/0000-0002-1976-345x https://orcid.org/0000-0003-4049-8395 original research sajsm vol. 31 no. 1 2019 2 relaxed according to the principle of reciprocal inhibition.[10] the increased stretch tolerance and pain threshold after stretching, combined with the above neurological mechanisms, should facilitate increased knee range of movement (rom) and hamstring muscle length following hamstring crac stretching. of concern is that previous studies found that there may be a stretch-induced deficit in muscle performance after an acute stretching protocol.[4] this effect seems more pronounced with a static stretch of longer duration.[4] furthermore, there is also conflicting evidence for the degree of stretch-induced deficit between different stretch techniques.[11] the stretch-induced performance deficit concept is based on the theory that a more compliant musculotendinous unit has non-optimal sarcomere cross-bridge kinetics after stretching. this delays the production of tension within the sarcomere and the subsequent force transmission from the musculotendinous unit to the tenoperiosteal junction.[11] statement of the problem despite evidence that crac stretching is effective in increasing the length of the hamstrings, there are only a few studies that have investigated both the changes in hamstring flexibility following crac stretching and the impact on the function of this increased length.[12] while the duration of maintained flexibility has been defined following acute static and contract-relax (cr) hamstring stretching protocols, this effect has not been established following acute hamstring crac stretching.[13, 14] the principle aim of this study was to determine the effects of the crac stretch of the hamstrings on functional measures of muscle performance, such as flexibility, agility and sprint performance. the secondary aim was to establish the duration of maintained hamstring flexibility after the acute application of the hamstring crac stretch. methods study design the study used a randomised control experimental design to investigate the short-term effects of a crac technique on the hamstring muscles in fit adult men. participants were randomly assigned to an experimental group that received a crac stretch or a control group that received no intervention participants participants included healthy, active males (21 to 35 years old) who participated in three and five hours of physical activity per week. they were recruited for the study through advertisements placed at gymnasiums in cape town, south africa, and through word of mouth. data from a previous study that measured hamstring flexibility using the active knee extension test were used to ensure that the sample size would provide sufficient statistical power.[14] in order to detect the smallest meaningful difference of 15º between the mean range of movement of the two groups with a standard deviation of 10º, with an alpha of .05 and a power of 90% statistical power, 20 participants were required for each group. forty participants were therefore recruited to participate in the study. participants were required to complete a questionnaire that requested relevant medical, surgical and training-related history as a method of screening for possible exclusion criteria and to determine participant eligibility for the study. participants that had a previous history of hamstring injury or pathology of the hips, knees, thighs or lower back over the last three months; regular use of muscle relaxants, analgesic, steroidal or non-steroidal anti-inflammatory drugs; orthopaedic or neuromuscular diseases of the lower limbs were excluded from the study. participants were randomly assigned to either the experimental group or control group at the baseline testing session, following the completion of the informed consent form and relevant questionnaires. randomisation was conducted by asking participants to draw a piece of paper from an envelope. the envelope contained an equal number of “experimental” and “control” group slips. instrumentation body mass (kg) was documented using a calibrated scale, and stature (m) was recorded using a wall-mounted stadiometer. hamstring flexibility was assessed using the active knee extension (ake) test.[15] participants were placed in a supine position, without the use of a pillow. they were also instructed to allow the ankle to plantar flex during testing to limit the effect of potential increased neural tension that may occur if the ankle went into dorsiflexion. an adjustable strap was placed over the anterior superior iliac spine to limit pelvic movement during testing. an additional strap was placed over the thigh of the leg not being tested to maintain hip extension. the leg being tested was placed on a wooden platform which was used to maintain 90º of hip and knee flexion. these positions were established using a universal goniometer. an inclinometer was aligned with the head of the fibula and lateral malleolus and adjusted to zero. the participants were instructed to extend the knee actively at a slow rate to avoid hamstring muscle spindle excitation until the first onset of a stretch sensation was perceived, as opposed to a feeling of discomfort. at this point, the angle on the inclinometer was recorded. the participant then returned the leg to the starting position and rested for one minute. the average of three inclinometer recordings was recorded. the ake test was then repeated on the opposite leg. the illinois agility test was used to determine agility performance.[16] the test involves explosive speed, rapid changes of direction, deceleration and the ability to maintain momentum and balance as a measure of four-directional agility. previous studies have determined that the illinois agility test is a valid and reliable method of testing agility.[16] sprint performance was determined by measuring the sprint time over 10 m and 25 m respectively. participants were given standard verbal encouragement during the test and were requested to complete the course “as fast as possible”. timing for both the agility and sprint tests was manually performed on a stopwatch. the reliability of the 10 m sprint has previously been established.[17] the method described by mcatee [8] and schuback et al.[6] was used for the crac procedure. in the same position used to test original research 3 sajsm vol. 31 no. 1 2019 ake, the primary investigator (a physiotherapist) guided the leg into a straight leg raise until the participant reported the first onset of a stretch sensation in the hamstring muscles. this position was maintained for 15 seconds, with the primary investigator supporting the participant’s ankle by means of this investigator’s shoulder. the participant then performed a maximal isometric contraction of the muscles for six seconds pushing the leg into hip extension. the primary investigator resisted the contraction at the level of the participant’s ankle to assist ergonomic endurance. immediately after the hamstring muscle’s isometric contraction, the participant was asked to perform a concentric hip flexion muscle contraction against the primary investigator’s manual resistance. the primary investigator encouraged the participant to reach the hip flexion limit and to maintain this for six seconds. a 20 second rest after the concentric hip flexion marked the end of one repetition. three repetitions of the crac stretch were performed for each leg by the primary investigator using standardised verbal instructions to ensure consistency and maximum cooperation from participants. procedure the study was granted ethical clearance by the university of cape town’s faculty of health sciences human ethics research committee (ethical clearance no. 200/2009). this study was performed in accordance with the ethical principles outlined in the wma declaration of helsinki, fortaleza, brazil, 2013. participants were tested individually and required to attend three testing sessions at similar times on alternate days over the course of one week. all tests were conducted on a non-slip indoor track thereby ensuring a consistent testing environment. body mass and stature were assessed in all participants. participants were then randomised into either the experimental or control group and familiarised with all testing procedures. the experimental group was also familiarised with the crac stretch via a visual demonstration performed by the primary investigator. the participants’ hamstring flexibility, agility and sprint performance were then measured. during the second session, all participants had their preintervention hamstring flexibility recorded. participants in both groups performed a standardised warm-up which consisted of five minutes of cycling between 100 watts to 120 watts on a stationary cycle ergometer with a magnetic resistance flywheel. participants in the experimental group received a crac stretch performed bilaterally by the primary investigator. participants in the control group rested supine for six minutes which was the same duration as for the experimental group’s crac stretch. they then had their hamstring flexibility measured using the ake test. this was followed immediately by recording the better of two trials of agility and sprint performance tests measured using the illinois agility test and sprint test, respectively. at the third testing session, the duration of effect of the crac stretch was assessed through repeated measures. for all participants, pre-intervention hamstring flexibility was recorded bilaterally, followed by the standardised warm-up. participants in the experimental group then received the crac stretch, performed on each leg, by the primary investigator. participants in the control group rested supine for the same duration as was required for the crac stretch to be performed. statistical analysis statistical analyses were performed using statistica software [statsoft, inc. (2007). statistica (data analysis software system), version 8.0. www.statsoft.com]. normality was determined using the kolmorogov-smirnov test. differences in the descriptive variables between the experimental and control groups were assessed using an independent t-test. statistical significance for the two main effects of group and time, and the interaction (group x time) of duration of effect of the crac stretch were assessed using a two-way analysis of variance (anova) with repeated measures. tukey’s hsd post hoc comparisons were performed where necessary. differences in the three dependent variables (flexibility, agility and speed) were compared at preand post-intervention periods between groups using an independent t-test. as the body mass index (bmi) differed between groups, the pearson’s correlation between bmi and rom of the right leg and the change in rom was calculated. all data are presented as the mean ± standard deviation (sd), unless otherwise stated. statistical significance was accepted as p ≤ 0.05. results the participants from both groups took part in all the sessions. the descriptive characteristics of all participants are shown in table 1. there was a significant difference between groups in body mass (p=0.02), with participants in the experimental group having a significantly higher body mass compared to participants in the control group. there were no significant differences between groups for any other descriptive variables. the difference in hamstring flexibility (measured as degrees of active knee extension) prior to and immediately following crac stretching in the experimental group as compared to the control group (no intervention) is shown in table 2. note that an increase in ake indicates increased hamstring flexibility. there was a significant interaction between groups over time (f(7, 266)=38.95; p < 0.001) with an increase in active knee extension angle of the experimental group post-crac stretch compared to the control group. experimental group knee extension angle, immediately post-crac intervention, remained significantly increased for the duration of eight minutes compared to that of the experimental and control group’s baseline knee extension angle (p < 0.001). table 1. descriptive characteristics of participants in the experimental (n = 20) and control (n = 20) groups variable experimental control age (years) 24.1 ± 4.1 24.5 ± 3.9 stature (m) 1.76 ± 0.06 1.75 ± 0.06 body mass (kg) 79.0 ± 11.1 72.0 ± 7.5* body mass index (bmi) 25.3 ± 3.4 23.4 ± 2. data are expressed as mean ± standard deviation. * indicates p = 0.02 original research sajsm vol. 31 no. 1 2019 4 there were no significant correlations between bmi and either baseline rom of the right leg (r=0.20, p=0.22) or change in rom (r=-0.21, p=0.20). discussion the hamstring crac intervention was effective in improving hamstring flexibility immediately post-application and maintained significant hamstring flexibility for a duration of eight minutes thereafter. the crac intervention had no significant effect on agility or sprint times in moderately active males. the two groups were identical, apart from body weight, but as no correlation was found between bmi and change in rom, it is likely that any difference in outcome was as a result of the intervention. the role of crac in increasing hamstring length is supported by studies which reported similar results and was not unexpected.[5, 12] it is difficult to compare the increase with other studies as most did not report the percent increase but rather the mean gain in rom, which ranged from 1.6° to 15.7° after using crac on hamstrings.[18] using the ake test, an increase of 10% in rom was reported after using pnf techniques.[11] the 17.7° or 37% increase in range gained by crac compares well with the results of similar studies.[5, 12] in addition, the duration of effect was longer than previously reported. depino et al. reported a maximum duration of effect of three minutes after a static stretch and spernoga et al. reported significantly improved flexibility up to six minutes after a contract relax stretch.[13, 14] the practical relevance of the duration of hamstring crac stretch employed in this study is that three repetitions of the stretch (which would take approximately three minutes in total to perform on a patient) would result in increased flexibility for a minimum time of eight minutes. optimal timing of performance for warm-up or therapeutic exercises would be within this window of eight minutes after the stretch application, which could take place both pre-match and at intervals. the possible effects of crac on performance were more of a concern. however, the results indicate that crac does not seem to have the deleterious effects on performance that have been previously reported, particularly with static stretches.[4] as small decrements in performance can have major implications for elite sportspersons, it is reassuring that crac does not result in decreased performance. however, it is recommended that further studies be conducted using electronic timing to ensure greater precision of measurement. conclusion in conclusion, a set of three repetitions of crac applied to stretch the hamstring muscles of active males will result in an expected increase of up to 37% in active knee extension rom, without decreasing performance. it is suggested that crac is a safe and effective method of increasing the length of the hamstrings during pre-sport activities and should be utilised by sports physiotherapists, provided that it is deemed necessary and beneficial following the initial assessment future studies should also investigate chronic adaptations following regular long-term hamstring crac stretching and examine these effects on sprinting and agility tests in comparison to the effects of acute crac applications, such as the intervention used in this study. table 2. . comparison of preand post-intervention scores between the experimental (n = 20) and control (n = 20) groups variable experimental control t p hamstring flexibility (°) pre-intervention 48.2 ± 8.5 56.9 ± 13.4 -2.57 0.12 post-intervention 65.9 ± 8.6 58.0 ± 13.2 2.26 0.03* agility score (s) pre-intervention 16.9 ± 0.8 17.1 ± 1.8 -0.44 0.66 post-intervention 16.4 ± 0.8 16.7 ± 1.6 -0.88 0.38 best 10 m sprint (s) pre-intervention 2.0 ± 0.1 2.0 ± 0.3 -0.20 0.84 post-intervention 2.0 ± 0.1 2.0 ± 0.8 0.26 0.80 data are expressed as mean ± standard deviation. * indicates p <0.05 fig. 1. differences in duration of effect for participants in the experimental group (n=20) and control group (n=20). data are presented as mean ± standard deviation. significant differences: ** experimental baseline vs. experimental 0, 2, 4, 6 and 8 min (p < 0.001). # interaction of group x time (p < 0.001). original research 5 sajsm vol. 31 no. 1 2019 conflict of interest: the authors declare that they have no conflict of interest. author contributions: t burgess: conceived, analysed and wrote up the paper, and approved the final draft. t vadachalam: collected the data and wrote the initial research paper on which the paper is based. k buchholtz: assisted with writing and checking of the final draft. j jelsma: analysed, wrote up and approved the final draft. references 1. brukner p, nealon a, morgan c, et al. recurrent hamstring muscle injury: applying the limited evidence in the professional football setting with a seven-point programme. br j sports med 2014;48(11):929 -938. [ doi: 10.1136/bjsports-2012-091400] 2. mason dl, dickens va, vail a. rehabilitation for hamstring injuries. cochrane database syst rev 2012; 12:12-cd004575. [doi: 10.1002/14651858.cd004575.pub3] 3. brukner p, clarsen b, cook j, et al. brukner & khan’s clinical sports medicine: injuries, vol.1. 5th ed. sydney, australia: mcgraw-hill education, 2016. chapter 31, p600-602. 4. shrier i, mchugh m. does static stretching reduce maximal muscle performance? a review. clin j sport med 2012;22(5):450–451. [doi: 10.1097/jsm.0b013e31826a08ee] 5. feland jb, marin hn. effect of submaximal contraction intensity in contract-relax proprioceptive neuromuscular facilitation stretching. br j sports med2004;38(4): e18. [ doi: 10.1136/bjsm.2003.010967] 6. schuback b, hooper j, salisbury l. a comparison of a selfstretch incorporating proprioceptive neuromuscular facilitation components and a therapist-applied pnf-technique on hamstring flexibility. physiotherapy 2004;90(3):151–157. [doi: 10.1016/j.physio.2004.02.009] 7. hindle kb, whitcomb tj, briggs wo, et al. proprioceptive neuromuscular facilitation (pnf): its mechanisms and effects on range of motion and muscular function. j hum kinet2012;31(1):105–113. [doi: 10.2478/v10078-012-0011-y] 8. mcatee re. an overview of facilitated stretching. j bodyw mov ther 2002;6(1):47–54. [http://dx.doi.org/10.1054/jbmt.2001.0258] 9. sharman mj, cresswell ag, riek s. proprioceptive neuromuscular facilitation stretching: mechanisms and clinical implications. sports med 2006;36(11):929–939. [doi: 10.2165/00007256-200636110-00002]. 10. condon s, hutton r. soleus muscle electromyographic activity and ankle dorsiflexion range of motion during four stretching procedures. phys ther 1987;67(1):24–30. [doi: 10.1093/ptj/67.1.24] 11. weerapong p, hume pa, kolt gs. stretching: mechanisms and benefits for sport performance and injury prevention. phys ther rev 2004;9(4):189–206. [doi:. 10.1179/108331904225007078] 12. ryan ee, rossi md, lopez r. the effects of the contract-relaxantagonist-contract form of proprioceptive neuromuscular facilitation stretching on postural stability. j strength cond res 2010;24(7):1888-1894. [doi: 10.1519/jsc.0b013e3181ddad9d] 13. depino gm, webright wg, arnold bl. duration of maintained hamstring flexibility after cessation of an acute static stretching protocol. j athl train 2000;35(1):56–59. [pmid: 16558609] 14. spernoga sg, uhl tl, arnold bl, et al. duration of maintained hamstring flexibility after a one-time, modified hold-relax stretching protocol. j athl train 2001;36(1):44–48. [pmid:12937514] 15. decoster lc, cleland j, altieri c, et al. the effects of hamstring stretching on range of motion: a systematic literature review. j orthop sport phys ther 2005;35(6):377–387. [doi: 10.2519/jospt.2005.35.6.377] 16. hachana y, chaabène h, nabli ma, et al. test-retest reliability, criterion-related validity, and minimal detectable change of the illinois agility test in male team sport athletes. j strength cond res 2013;27(10):2752–2759. [doi: 10.1519/jsc.0b013e3182890ac3] 17. little t, williams ag. effects of differential stretching protocols during warm-ups on high-speed motor capacities in professional soccer players. j strength cond res 2006;20(1):203–207. [doi: 10.1519/r-16944.1] 18. ferber r, osternig lr, gravelle dc. effect of pnf stretch techniques on knee flexor muscle emg activity in older adults. j electromyogr kinesiol 2002; 12(5):391–397. [ doi: 10.1016/s10506411(02)00047-0] abstracts 4th clinical sports medicine conference – injury prevention and protection of the health of the athlete, 13 15 october 2010, cape town prevalence of musculoskeletal pain among the south african female senior national hockey players ellapen tj, abrahams s, desai fa, narsigan s, van heerden sj discipline of sports science (biokinetics), faculty of health science, university of kwazulu-natal background. field hockey is a team sport in which the competing teams attempt to score into the opposing team’s goal. in an attempt to score goals, players sprint (with possession of the ball) making sudden changes in the direction of movement around their opponents, which increases the risk of musculoskeletal injury and pain. objectives. this study documented the prevalence of hockey-related musculoskeletal pain among the south african female senior national hockey team (n=30). subjects. all subjects were members of the south african national senior hockey team (n=30). methods. subjects completed a self-report questionnaire which gathered their biographical, epidemiological and exercise history over the last 12 months. the following descriptive statistics (mode, mean, frequency, percentages) and inferential statistics (chi-square set at a probability of 0.05) were used to analyse the data. results. twenty-eight (93.33%) of the cohort sustained musculoskeletal pain within the last 12 months (p<0.001). the most prevalent anatomical sites that sustained hockey-related musculoskeletal pain were the ankles (24.14%), lower back and hip (22.41%), lower leg (13.79%), knees (12.07%) and thighs (10.34%) (p<0.01). the predisposing mechanisms for producing the hockey-related musculoskeletal pain were rapid, rotational movements (43.75%), collisions with players (18.75%), and being struck with the ball (12.5%) (p<0.01). conclusion. the south african senior female hockey team experienced a high prevalence of hockey-related musculoskeletal pain, especially at their ankles, lower back and hip areas. prevalence of karate-related musculoskeletal pain among skisa karatekas ellapen tj, abrahams s, desai fa, narsigan s, van heerden hj discipline of sports science (biokinetics), faculty of health science, university of kwazulu-natal background. over the past decade, there has been heightened interest in the philosophy, training habits, nutrition and epidemiology of martial arts athletes. despite this interest in the martial arts, there is a dearth of research publications on the epidemiology and training history of unique karate martial arts athletes, more specifically shotokhan karate-do-international south africa (skisa) karatekas. objectives. this study investigated the prevalence of karate-related musculoskeletal pain among skisa athletes. subjects. one hundred and sixty karatekas participated in a retrospective epidemiological investigation by voluntary informed consent. subjects were martial art practitioners belonging to skisa who took part in their 2010 national skisa kanazawa-cup tournament. methods. the subjects’ training history and epidemiology of karaterelated musculoskeletal pain were gathered by means of a validated musculoskeletal pain questionnaire, which was adapted for use in this study. descriptive statistics which included the mode, mean, frequency, percentages and inferential statistics comprising of chisquare tests (with the probability set at 0.05) were employed in the statistical analysis. results. out of the 160 karatekas who completed the questionnaire, 61.88% (n=99) experienced karate-related musculoskeletal pain (p<0.01). the prevalence of karate-related musculoskeletal pain to specific anatomical sites were hand (18.64%), feet (16.95%), leg (14.41%), knee (12.29%), back (11.86%), shoulder (8.47%), neck (4.24%), elbow (2.12%), and other (11%) (p<0.01). the predisposing mechanism producing the karate-related musculoskeletal pain reported was direct physical trauma (59.59%) from semi-contact (p<0.01). the other factors contributing to karate-related musculoskeletal pain were overuse injuries, non-compliance to rehabilitation programmes and not seeking medical attention when musculoskeletal pain was initially experienced. conclusion. skisa athletes experienced a high prevalence of karate related musculoskeletal hand and foot pain. a comparison of perceived versus actual cardiovascular disease risk in black urban males and females jackson lm, christie cj department of human kinetics and ergonomics, rhodes university, grahamstown background. cardiovascular disease (cvd) is becoming increasingly prominent in developing countries, such as south africa, and particularly in previously ‘risk-free’ population groups, such as black south africans. however, aligned with this is the belief that many black men and women are cvd risk-free. objectives. the aim of this research was to compare perceived versus actual cvd risk in black males and females from an urban working population in the eastern cape. subjects. black urban males and females with a mean age of 41.6 years took part in the study (n=291). methods. obesity, hypertension, type 2 diabetes, and hypercholesterolaemia were considered as cvd risks. body mass index (bmi) was calculated from measures of stature and mass. obesity was classified according to bmi classification categories. the blood pressure of participants was assessed with a mercury sphygmomanomoral presentations 70 sajsm vol 22 no. 3 2010 sajsm vol 22 no. 3 2010 71 eter, readings from which were then classified according to jnc 7 hypertension guidelines. total blood glucose and cholesterol were assessed using an accutrend gc/gct reflectance photometer and classified according to who guidelines for type 2 diabetes, and ncep guidelines for the classification of hypercholesterolaemia. an adult health questionnaire (ahq) contained questions on individuals’ perceptions of the aforementioned risk factors. participants were required to answer if they perceived themselves to be at risk. these perceived responses were then compared with objective measures. results. although 93.2% of the female sample was classified as overweight/obese, only 44.6% perceived themselves to be overweight. within the male sample, 18.2% of individuals perceived themselves as overweight, while 44.8% were classified as such. thirty-five per cent of the females perceived that they were hypertensive, which was confirmed in 36% of the sample. in comparison, only 17% of males perceived themselves to be hypertensive, while 32% were hypertensive. while 9% of the females believed they had hypercholesterolaemia, 16% fulfilled the criteria for hypercholesterolaemia. with the males, 11% were hypercholesterolaemic, compared with 3% who believed they were. while 10% and 2% of males and females perceived themselves to have type 2 diabetes, this was the case in only 2% of females and none in the males. conclusions. there is inconsistency between perceived and actual cvd risk with a tendency for individuals to underestimate their level of risk. the impact of the frequency and duration of exercise programmes on the fitness levels of 11 13-year-old children narsigan s discipline of sports science (adapted sport science), faculty of health science, university of kwazulu-natal background. changes to the variables of exercise programmes greatly affect the outcome. investigations have been undertaken that examine the manipulation of frequency and duration on the exercise programmes of adults, but limited studies have been conducted on those of children. objectives. this study investigated the impact of frequency and duration of exercise programmes on the health-related fitness of 11 13-year-old children. subjects. the sample population consisted of 40 children from an urbanised area and a peri-urban area (n=20). the inclusion criteria for eligibility to participate in the study were participation in exercise and sport programmes. methods. a quasi-experimental quantitative study (an ex post facto) compared the fitness levels between the groups. an exclusion criterion was a chronic illness that prevented them from participating in physical activities. data were collected measuring the following dependent variables: body mass, stature, skinfold, resting heart rate, 1-minute sit-ups (abdominal strength and endurance) and 1-minute push-ups (upper body strength and endurance), 40-meter sprint (anaerobic capacity), 12-minute run (aerobic capacity), and modified sit and reach (flexibility). non-parametric statistics comprising of mode, mean, frequency, percentages and parametric statistics (independent t-test) were employed in the statistical analysis. results. the evidence indicated that the children from the urban area performed better in their 1-minute sit-ups (31.1±1.5 v. 20.9±1.5) and push-ups (22.4±1.7 v. 13.4±1.6), 40-meter dash (6.8±0.9 v. 7.8±0.1) and 12-minute run (1920m±97.3 v. 1682m±87.9) (p<0.05). in addition, children who resided in the urban area had a low per cent body fat compared with their peri-urban counterparts. conclusion. data showed that children from the urban area had superior health-related fitness levels compared with those from the peri-urban area. a comparison of intermittent and continuous cycling training on the cardiovascular health of postmenopausal women sheppard bj, christie cj department of human kinetics and ergonomics, rhodes university, grahamstown background. the risk of cardiovascular disease increases exponentially in postmenopausal women. exercise as a treatment has not been fully elucidated, particularly aerobic exercise training of an intermittent nature. objectives. to compare the effect of two types of aerobic cycling exercise (intermittent versus continuous) on selected health measures in this population group. subjects. eighteen previously sedentary, postmenopausal women (defined as no menses for 12 consecutive months) between 50 and 75 years old and in good health (non-smokers, no hypertension, diabetes mellitus, and not taking any form of hormone replacement therapy) were recruited from the grahamstown area in the eastern cape province of south africa. methods. subjects were randomly divided into two groups of equal numbers, representing the intermittent (exp) and the continuous (con) protocol, both involving stationary cycling of a progressive nature (for 8 weeks). all subjects attended three supervised exercise sessions per week, with an initial duration of 20 minutes per session, increasing to 28 minutes per session in the final 4 weeks. the training load for both groups was matched to allow any benefits to be directly attributed to the specific protocol. selected measurements (body mass, stature, waist and hip girth, blood pressure, reference heart rate and a full blood lipid profile) were obtained at weeks 0, 4 and 8 respectively. for the duration of the intervention, subjects were requested to maintain their habitual dietary intake and not to embark on any weight loss programme. results. there were no significant (p<0.05) alterations in body mass, waist and hip circumference, blood pressure, high density lipoprotein and triglyceride concentrations at the end of the 8-week period in either group. however, significant (p<0.05) reductions were observed in total cholesterol and low density lipoprotein concentrations after the initial 4 weeks within the exp group only. thereafter these measures increased significantly to pre-measurement values at 8 weeks. conclusions. although 4 weeks of intermittent cycle training resulted in an improvement in blood lipid concentrations, these benefits were no longer apparent at the end of the 8 weeks. it can therefore be concluded that 8 weeks of cycling training, whether of an intermittent or continuous nature, resulted in no positive alterations of certain cardiovascular risk measures in a cohort of postmenopausal women. comparative ultrasound study of acute lateral ankle ligament injuries rehabilitated with standard and jump stretch flex band programmes van der linde e, oschman z section sports medicine, faculty of health sciences, university of pretoria background. lateral ankle ligament injuries are very common in sport. we were interested in finding a suitable rehabilitation method to get sportsmen and women back to the playing field as soon as possible with minimal risk. objectives. to establish whether rehabilitation with the jump stretch flex band (jsfb) programme would be superior to standard ankle rehabilitation of acute lateral ankle ligament injuries. subjects. all rugby and non-rugby players with acute lateral ankle ligament injuries were considered potential subjects. methods. ultrasound examinations were done 72 hours post injury and repeated 2 weeks post rehabilitation. swelling, thickness, appearance of ligaments and recovery time were compared in grades 1 and 2 ankle ligament injuries. after we had distinguished the amount of tissue damage, we started a rehabilitation programme where the patients were divided into group a (study group) or group b (control group). group a received jsfb rehabilitation from day 4 post injury onwards, whereas group b started with a standard ankle rehabilitation programme from day 10 post injury onwards. an ultrasound examination was done on each patient every 2 weeks to compare the amount of tissue healing in both groups. only well-researched and acknowledged techniques were used for the study. results. the anterior talo-fibular ligament (atfl) of both groups a and b tended to increase in size with the jsfb over 2-week time intervals (p=0.0025, u=0 for grade 1; p=0.0038, u=0 for grade 2). the fluid in the anterior recess decreased more with the jsfb (p=0.0426, u=5) for ggade 1 injuries and less than the standard ankle rehabilitation programme for grade 2 injuries (p=0.33, u=12.0). fluid from the posterior recess was decreased more for both grade 1 and 2 injuries with the jsfb (p=0.1184, u=30.5 for grade 1; p=0.47, u=22.0 for grade 2). the recovery time (rt) of grade 1 ankle injuries rehabilitated with a jsfb were on average 11 days shorter than grade 1 ankle injuries rehabilitated on a standard ankle rehabilitation programme (p=0.0026, u=0). similar results were found with grade 2 ankle injuries. the recovery times (rt) of grade 2 ankle injuries on the jsfb were on average 12 days shorter than those of grade 2 ankle injuries rehabilitated on a standard ankle rehabilitation programme (p=0.0081, u=1.5). we only had one patient with a re-injury 2 months post rehabilitation on an ankle rehabilitated with the standard ankle rehabilitation programme, and no re-injuries for ankles rehabilitated on the jsfb. in general, there was a tendency for the appearance of the atfl to have a more significant change from abnormal to normal with the jsfb than that of a standard ankle rehabilitation programme for grades 1 and 2 ankle ligament injuries (p=0.0699 for grade 1; p=0.0606 for grade 2). thus the jsfb proved to be more effective. conclusions. rehabilitation with the jsfb programme proved to be superior to standard ankle rehabilitation. grades 1 and 2 ankle ligament injuries recovered sooner, resulting in stronger ligaments, and no re-injuries were reported. the general public may benefit in returning to their daily activities much sooner, and athletes may resume normal competition without any delay. range of motion diverges with increasing age for the col5a1 bstui genotypes brown jc, miller c-j, schwellnus mp, collins m uct/mrc research unit for exercise science and sports medicine, dept of human biology, faculty of health sciences university of cape town background. both an increased and decreased flexibility/joint range of motion (rom) is a modifiable risk factor for musculoskeletal softtissue injuries. mutations within the col5a1 gene have been shown to cause heritable disorders of connective tissue, which have a unifying symptom of joint hypermobility. furthermore, a col5a1 gene sequence variant, the bstui restriction fragment length polymorphism (rflp), is associated with range of motion (rom) measurements in a population of individuals with a history of achilles tendon injuries. objectives. to investigate the possible association between the col5a1 gene bstui rflp and sit and reach rom in an apparently healthy and physically active population. subjects. three hundred and twenty-five (of which 204 were males) white, apparently healthy and physically active subjects were recruited from local fitness centres and running events. methods. the sit and reach (sr) test and genotyping of the bstui rflp (c/t) within the 3’-untranslated region of the col5a1 gene was performed on all subjects. detailed medical questionnaires on training status, injury and medical history were also completed by all subjects. results. while the col5a1 bstui rflp genotypes were not associated with sr rom in the ‘young’ (<35 years) subjects (n=197, p=0.626), there was a significant difference in the mean sr rom between the genotype groups of the ‘old’ (≥35 years) subjects (tt=225±96mm, tc=245±100mm, cc=321±108mm, n=96, p=0.017). a significant interaction between age and col5a1 bstui genotype explained the difference in sr mean scores with increasing age. furthermore, only two factors, gender and bstui genotype, explained a significant proportion (22.8%) of the variance in sr rom in the ‘old’ group. conclusions. the col5a1 bstui rflp is associated with sr rom, particularly with increasing age, and this finding partially explains the results of previous reports from this laboratory. this study suggests that genotype, along with other common intrinsic and extrinsic phenotypic factors, should be considered when assessing rom. importance of tachogram length and period of recording during the non-invasive investigation of the autonomic nervous system grant cc1, janse van rensburg dc1 , strydom n2, viljoen m3 1 section sports medicine, faculty of health sciences, university of pretoria 2 department of statistics, university of pretoria 3 department of physiology, faculty of health sciences, university of pretoria background. various disciplines, including research in health and prevention in sports medicine, use quantification of heart rate variability as an indicator of autonomic function without recognising the importance of using standardised methodologies. 72 sajsm vol 22 no. 3 2010 sajsm vol 22 no. 3 2010 73 objective. the aim of this study was to assess the influence of tachogram length and period of recording on heart rate variability (hrv) indicator values. methods. to test the influence of the length of the recording time, hrv indicator values calculated from 180, 300, 420, and 600 seconds recording periods (supine and standing) were compared. also, individual 3-minute periods (0 180 s, 180 360 s, 360 540 s) from 10-minute (supine and standing) tachograms were compared. results. in the supine position, vagal efferent hrv indicators were not influenced by tachogram length varying between 3 and 10 minutes (p>0.05). supine hrv indicator values representing combined sympathetic and parasympathetic influences were tachogram length-dependent (p<0.05). during orthostatic stress, all hrv indicators were tachogram length-dependent (p<0.05). upon standing up, marked vagal withdrawal and sympathetic activation occurred. vagal withdrawal tapered off during the 3 6-minute period after rising, while indicators representing combined vagal and sympathetic activation were totally reversed. conclusions. during the application of orthostatic stress the exact starting point of recording, as well as the length of recording, is critical due to the activation and normalisation of homeostatic mechanisms. starting the tachogram recording too late will miss out part of the initial response to change in body position. longer recording times will give a combination of values recorded during the stress response and values obtained after stabilisation in the standing position. impact of clothing and protective gear on physiological, perceptual and performance responses during simulated rugby activity cannon mj, christie cj human kinetics and ergonomics department, rhodes university, grahamstown background. there is a lack of information regarding the influence of clothing and protective gear on rugby players’ physiological, perceptual and performance responses during simulated rugby activity. objectives. to compare players’ responses when wearing minimal rugby clothing and no protective gear (control condition cc), and when wearing full rugby clothing and protective gear (experimental condition ec). subjects. eight makulu blue rugby players from the rhodes university internal rugby league were selected as subjects. methods. players performed a simulated 40-minute (2 x 20-minute) intermittent running rugby protocol which excluded contact rugby activities. players performed the protocol between two points, set 20 meters apart, by standing, walking, jogging, striding and sprinting intermittently when instructed to do so by the tester. this protocol was very stop/start and intermittent in nature, which matched the demands of a real rugby match. test subjects performed this protocol wearing either the control kit or the experimental kit. with both protocols, physiological (skin temperature, fluid loss and heart rate) and perceptual measures (ratings of perceived exertion and thermal discomfort) were recorded prior to testing, and then at 10-minute intervals during the protocol. prior to testing and following both conditions, players performed a multi-stage 20-metre shuttle run (performance measure) wearing only the control kit. results. the intermittent rugby protocol was the greatest stressor, with protective gear exacerbating these effects. skin temperature increased significantly from the start to the end (0 40 minutes) of the ec (mean of 34.8°c), while skin temperature reached a ‘steady state’ during the cc (mean of 31.9°c). heart rate increased significantly in the transition from rest to exercise and thereafter stabilised in both conditions. this excluded the last time interval when heart rate increased significantly (p<0.01) in both conditions, although heart rates at this time interval were significantly higher in the ec (mean of 184 bt.min -1 ) compared with the cc (mean of 167 bt.min -1 ). during the ec, fluid loss was significantly greater (0.79 liter compared with 0.57 liter in the ec and cc respectively) because of an increased absolute sweat rate. despite the increased physiological strain, players did not perceive this extra strain until the end of the ec protocol. furthermore, players perceived significantly more thermal strain during the ec. the most important finding was that performance was significantly compromised following the ec. conclusion. it is contended that the intermittent nature of rugby imposes physical stress on players. the stress is greater when these players wear full rugby clothing and protective gear. the combined impact of intermittent exercise plus clothing and protective gear had a detrimental effect on performance. a pathway-based approach investigating the inflammatory pathway and predisposition to the development of achilles tendinopathy nell e-m, collins m, schwellnus mp, september av uct/mrc research unit for exercise science and sports medicine, department of human biology, university of cape town background. achilles tendinopathy (at) is a multifactorial condition for which several genetic risk factors have been identified. at is characterised by altered expression of several cytokines and inflammatory mediators. recently, the il-1β, il-1rn and il-6 genes were found to modulate risk of at in combination with the col5a1 bstui rflp. therefore genes encoding mediators of the il-1β matrix degradation pathway (cox-2, ptger4) and mediators of the il-6 apoptosis pathway (casp8, nos3) were explored for associations to at. objectives. the aim of this study was to determine whether functional polymorphisms within the cox-2, ptger4, casp8 and nos3 genes, encoding proteins involved in extracellular matrix (ecm) degradation and tenocyte apoptosis, may contribute towards a risk of at in south african (sa) and australian (aus) individuals. subjects. a total of 163 asymptomatic controls (sa con) and 93 participants with at (sa ten) from sa and 210 aus con and 85 aus ten participants were recruited. methods. a pathway-based case-control genetic association study was conducted. participants were genotyped for rs20417 (cox2765g>c), rs4495224 (ptger4 gene desert a>c), rs3834129 (casp8-652 6ndel) and rs1799983 (nos3glu298asp). results. the casp8-652 del/del genotype was significantly overrepresented in aus ten compared to aus con (p=0.027; or=2.0, 95%ci 1.1–3.6). the casp8-652 ins/del genotype (p=0.029; or=1.8, 95%ci 1.1–3.1) and ptger4 cc genotype (p=0.010; or=4.4, 95%ci 1.3–15) were significantly over-represented in aus con compared to aus ten. no associations were observed for cox2-765g>c and nos3glu298asp in aus. no genotype or allele associations were observed in sa. conclusions. variations within genes involved in the inflammatory pathway modulate risk of at. this research emphasises that a pathway-based genetic association study may be a more effective approach to capture and understand the genetic risk factors underlying multifactorial conditions, such as at. electromyographic (emg) activity of vastus medialis obliquus (vmo) and vastus lateralis (vl) during isokinetic knee extension at various velocities neveling n, moshoeu l biokinetics, department of sport, rehabilitation & dental sciences, tshwane university of technology background. it has been stated that vmo:vl strength ratio should be 1:1 in order to maintain appropriate patella alignment, and that the response time for vmo should be less than vl. several authors have indicated that slower response times or weaker ratios may lead to excessive lateral patella tracking, predisposing the individual to injury. current literature shows conflicting results in this regard, with results varying from a response time favouring vmo, vl, or neither of the muscles. it has been proposed that these confounding results regarding vmo and vl electrical activity could be directly related to differences in methods, subject selection, electrode placements and level of loading. objectives. the purpose of the current study was to investigate whether there is a difference in emg activity of vmo and vl during isokinetic knee extension at 60°/s, 90°/s and 180°/s respectively. subjects. twenty male participants who were accustomed to strength training took part in the study. methods. each subject underwent three familiarisation trails with isokinetic and emg testing prior to the study. following a standardised warm-up on a cycle ergometer, each participant performed 5 maximal isokinetic repetitions at 60°/s, 90°/s and 180°/s with 1 minute rest between sets. the sequence of testing was randomised. emg data was recorded from the vmo and vl for each repetition, with the best values being analysed. results. the vmo: vl ratio was 113.9%, 105.4%, and 107.5% for 60°/s, 90°/s and 180°/s respectively. no significant differences were observed between testing velocities. no significant differences in the peak emg activity for vmo and vl were observed during isokinetic knee extension at 3 velocities. conclusions. this indicates that the vmo and vl contract at approximately the same intensity, with ratios being close to 1. as the testing was not repeated on individuals, further research should investigate whether re-testing the participants would result in changes regarding emg activity of vmo and vl at various velocities. the effect of neuro-lymphatic reflex muscle activation techniques on quadriceps strength during isokinetic training neveling n, bekker s, tshabalala nf biokinetics, department of sport, rehabilitation & dental sciences, tshwane university of technology background. muscle activation techniques rely on a system of neuro-lymphatic reflexes in the body to increase the neural drive to a specified muscle. the general technique entails rubbing an activation point over a reflex area for 10 20 seconds to increase the brain’s ‘awareness’ of the muscle to improve performance. this technique has gained popularity in recent years, with very little scientific backing. objectives. to determine the effect of neuro-lymphatic reflex muscle activation techniques on quadriceps strength during isokinetic training. subjects. fifteen sedentary female subjects were used in the study. methods. all subjects underwent three separate familiarisation sessions on the isokinetic equipment and with the general techniques of neuro-lymphatic reflex muscle activation prior to the initial testing to minimise possible training effects. a randomised, placebo-controlled design was used during the study. on day 1 of the testing subjects underwent activation on the reflex area for the quadriceps (experimental), a placebo site (placebo), or no activation at all (baseline). isokinetic knee flexion/extension testing was performed immediately following the activation at 60°/s. the testing was repeated 1 week later with alternate activation. the differences in peak torque for each testing session were compared with the baseline values using a t-test. results were also analysed for a learning effect using an anova. results. no learning effect was observed. it was further noted that no significant differences (p>0.05) were observed for peak isokinetic torque for the quadriceps (p=0.06), hamstrings (p=0.17), or the quadriceps:hamstring ratios (p=0.89). conclusions. based on these values, it would appear that, at least for the quadriceps, neuro-lymphatic reflex muscle activation does not lead to an increase in muscle strength. it is plausible that the anecdotal improvements that have been commonly referred to may be linked to psychosomatic improvements through suggestion. it should be noted that the study population in this trial was small. differences in muscle activation patterns across the menstrual cycle sauer jw, neveling n biokinetics, department of sport, rehabilitation & dental sciences, tshwane university of technology background. research has shown that females experience more anterior cruciate ligament (acl) injuries than males. even though anatomical and neuromuscular factors contribute to the above, it has also been suggested that this could be linked to changes in hormone levels. oestrogen has been linked to decreased strength and increased ligament laxity in females. objectives. to determine whether there is a difference between the muscle strength and activation patterns in females across the menstrual cycle. poster presentations 74 sajsm vol 22 no. 3 2010 sajsm vol 22 no. 3 2010 75 subjects. seven female and eight male subjects took part in the study. methods. the ovulatory (corrected day 14) and follicular (corrected day 21) was estimated for each female participant from a menstrual history recall questionnaire. each female subject was tested on each of these days, with male subjects being tested as controls on the same days. the order of the testing (ovulatory v. follicular) was randomised. for each testing session, isokinetic peak torque was assessed on an isokinetic dynamometer at 60°/s and 180°/s respectively. emg activation patterns for rectus femoris (rf), vastus lateralis (vl), vastus medialis (vm), biceps femoris (bf), semitendinosus (st), and medial gastrocnemius (g) was assessed during three drop landings from a 36 cm height. results. no significant differences were observed in the quadriceps peak torque or time to peak torque. the hamstrings showed a decrease in peak torque during the ovulatory phase, even though this was not significant. a significant difference (p<0.05) was found in time to peak torque for isokinetic hamstring strength between the menstrual phases. emg amplitude showed no significant difference during the menstrual phases during drop landing. time to muscle activation changed significant (p<0.05) for vmo, st, and bf showing slower activation during the ovulatory phase compared to the follicular phase. conclusions. delayed hamstring activation may predispose females to acl injury during the ovulatory phase. this delayed activation may be linked to decreased reflex activation of the hamstrings, leading to increased anterior tibial translation and load on the acl. this can possibly partly explain the increased risk for acl injury seen in females during the menstrual cycle. possible shortcomings include that the phases of the cycle was not confirmed by blood analysis, and the small sample size. the col5a1 gene, ultra-marathon running performance and sit and reach range of motion brown jc, miller c-j, posthumus m, schwellnus mp, collins m uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town background. endurance running performance and joint range of motion (rom) are both multifactorial phenotypes. the col5a1 gene has been separately associated with both endurance running performance and sit and reaches range of motion (sr rom). sr rom has been associated with running economy, a key predictor of endurance running performance. objectives. to investigate whether sr rom is related to running performance in an ultra-endurance event and if this relationship would be associated with the col5a1 genotype. subjects. seventy-two white runners (52 male) were recruited from the two oceans 56 km ultra-marathon. methods. subjects performed a pre-race sr test and donated a 5 ml blood sample. the cohort was genotyped for the (t/c) col5a1 bstui rflp. subjects completed a questionnaire on training history. race times were collected after the event from the official event website. results. the tt genotype (341±41mins, n=21) was significantly associated (p=0.048) with better overall ultra-marathon running performance in comparison to the c allele (tc + cc genotypes) (365±39mins, n=50). in contrast, the cc genotype (304±94mm, n=18) had significantly greater pre-race sr rom than the t allele (tt + tc genotypes) (241±95mm, n=54) (p=0.018). furthermore, age and col5a1 genotype accounted for a significant proportion of the variance in overall race time (19%). furthermore, when divided into quartiles based on rom and overall race time, the t allele were significantly over-represented in the ‘fast-inflexible’ group (t, 69% v. 47% c; p=0.044). conclusions. the col5a1 genotype was independently associated with both pre-race sr rom and performance in an ultra-endurance running event. however, there was no evidence of a direct association between rom and performance, although the t allele was significantly over-represented in the ‘fast-inflexible’ group. i was recently asked for my opinion about a proposal which was submitted to an administrative body which controlled high-performance sport. this proposal described a ‘patented’ method which purported to be able to optimise physical training, physical therapy, weight loss, injury detection and treatment and other health care applications. in other words, this simple, non-invasive measurement was supposed to do what a team of highly trained support staff members should be doing. too good to be true? or entrepreneurs at work using pseudo-science as their marketing tool? it was interesting to read how the proposal had been compiled and it confirmed my belief that some people are very skilful at trying to dupe consumers into purchasing something that is really worthless. in reading the proposal i realised that the first step of the pseudo-scientists is to manufacture a profile. this is done by having several letters after their names implying many years of postgraduate study. furthermore, the address of the ‘director’ is often listed as that of a consultant at a nondescript institute. this elevated profile is an attempt to gain the readers’ confidence before the next step in the process can be approached. the next step usually involves a bombardment of statistics which are often meaningless and for which there is no means of verification. this ostensibly gives the product credibility. this step is followed by a strategy which is also designed to gain the readers’ confidence and includes a detailed pseudoscientific description of what the test can possibly do. this is usually written in a confusing style clearly taking to heart the old saying: ‘if you cannot dazzle them with brilliance, baffle them with b******t’. typically the reader is bombarded with several references of published studies. a closer examination of the references will show that they have absolutely nothing to do with the product. however, a cursory read of the article with all the references cited at the end will certainly influence someone into thinking that the product is really supported by a large body of published material. the next step in this skilful marketing exercise is to state some unrealistic claims of what the product can do. while this strategy is well known in the weight-loss industry, it is starting to become more popular in the exercise health and fitness industry where claims of miraculous recovery from training and injury are being made. at present there is no body that can legislate over false advertising, particularly when it comes to claims about exercise. while there are some vigilant groups that monitor adverts about nutritional products and weight-loss products there are no groups that complain when products are marketed under the guise of being a miraculous adjunct to exercise training. clearly this is a gap in the market that some shrewd business people have observed. as health professionals coming from an evidence-based background the duty falls on all of us to be observant and not fall into the traps which these skilful pseudo-scientists have set. at present, when it comes to improving exercise performance it can be said with confidence that there is no magic formula that is going to work better than a systematic approach to training and adequate recovery coupled to innovative coaching. anyone who claims to have a secret formula which works better than this approach is clearly trying to make a quick profit at someone else’s expense. this third edition of the south african journal of sports medicine in 2007 has a variety of papers which should hopefully cover the interests of all the members of the south african sports medicine association. this edition of the journal also includes an insert which presents a ‘report card’ related to health and fitness for school children in south africa. the compilation of this report involved collaboration from scientists around the country. all the major relevant studies of schoolchildren in south africa were included in the report and the data were translated into practical outcomes. this was a great exercise to bridge the communication gap between scientists, the media, educators and parents and is an exercise which should also be conducted in the services delivered under the broad umbrella of sports medicine. mike lambert editor-in-chief innovation or fraud? a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial sajsm vol 19 no. 3 2007 65 pg65.indd 65 10/3/07 3:31:11 pm original research sajsm vol. 24 no. 4 2012 117 participation in sporting activities carries an injury risk. conversely, the increased awareness that physical inactivity is a major risk factor for disease has led government agencies and the medical community to encourage increased levels of physical activity. many people will achieve this through participation in sport. injury inevitably leads to a reduction in participation on a temporary or permanent basis, but the injury experience may also influence the lifelong physical activity behaviour. few studies adequately examine the possible long-term consequences of sport participation after the competitive period has been completed, but by understanding the patterns of injuries in different sports one test can develop strategies to prevent and better manage the conditions that occur and promote lifelong physical activity. there is a need to develop models of understanding of injury risk at different life phases and levels of participation in a specific sport. the risk assessment of sport participation has to be relevant to a particular sport, the level of participation, skill, age and potential future health consequences. this article describes a sport-specific model which will improve guidance for coaches and healthcare professionals. it poses questions for sports physicians, healthcare providers, educators and for governing bodies of sports to address in a systematic fashion. additionally the governing body, as an employer, will need to meet the requirements for risk assessment for professional sport and its ethical responsibility to the athlete. s afr j sm 2012;24(4):117-121. doi:10.7196/sajsm.356 lifetime injury prevention: the sport profile model* n webborn university of brighton, sussex centre for sport and exercise medicine, sportswise limited, the welkin, eastbourne bn20 7sn, uk n webborn corresponding author: n webborn (nickwebborn@sportswise.org.uk) editor's choice participation in sporting activities carries an injury risk.1,2 conversely, the increased awareness that physical inactivity is a major risk factor for disease has led the government agencies and the medical community to encourage increased levels of physical activity.3,4 many people will achieve this through participation in a sport. the consequence of increased participation in a sport is an increase in the musculoskeletal injury.5 the injury inevitably leads to a reduction in the participation on a temporary or on a permanent basis, but the injury experience may also influence lifelong physical activity behaviour.6-8 by understanding the patterns of injuries in different sports, we can develop strategies to prevent and better manage the conditions that occur and promote lifelong physical activity. for funded athletes in elite sport in the uk, and for professional sportsmen, the sport is their occupation, their means of financial support. their sporting career may also determine their financial future. this creates wider implications for injury prevention with regard to the roles and responsibilities of sports’ governing bodies. there is an obligation for any employer to assess the health and safety in the workplace. an employee who has been exposed to a health risk during their period of employment has a justifiable right to know what sort of risk they are exposing themselves to and what are the potential longterm consequences (ltcs) to their health of that employment. from the perspective of the health and safety executive, it is about reducing the risk to ‘as low as reasonably practicable’.9 the concept of ‘reasonably practicable’ lies at the heart of the british health and safety system and requires that an assessment must be made by the employer ‘in which the quantum of risk is placed on one scale and the sacrifice involved in the measures necessary for averting the risk (whether in money, time or trouble) is placed in the other’. can sport employers automatically assume the concept of ‘volenti non fit injuria’ (latin: ‘to a willing person, no injury is done’) because athletes willingly participate though they were unaware of the potential consequences of participation? the concept is based on the person accepting and being aware of the risks inherent in that event, so that they cannot later have an injury or seek compensation for it. how can we reasonably expect any individual to make a considered judgement if the assessment of risk to health has not been made by the governing body? the evidence for the increased risk of knee and hip osteoarthritis in former professional soccer players is convincing, but are the players informed of this known risk?10-14 should athletes have to accept long-term health consequences as ‘part of the game’ if there were preventive measures that could have been taken or if they were not informed of the risk? sports injury surveillance aims to reduce the risk of injury through identifying the size and severity of injury problems, by understanding the causes and mechanisms, and then by introducing preventive measures to attempt to reduce those risks. the model of van mechelen is widely accepted as a good model of injury prevention.15 it works very well in assessing a particular situation in a sport, but we must be mindful that we also need to consider age, skill, experience and the competitive level of the participants, and not apply the results of such a survey equally to all situations for that sport. injury surveillance is a complex issue given the nature of injury causation related to multiple factors, including, for example, the too early return to play from a preceding injury, described as the ‘recursive nature of risk and causation’.16,17 the fédération internationale de football association (fifa) and union of european football associations (uefa) are making efforts through collaborative research and the fifa medical and research centres (f-marc) to identify the frequency and characteristics of injury with a view to developing injury prevention strategies.18-20 the rugby football union has also instituted injury surveillance in professional rugby,21-25 but this is solely at an elite level and as yet there is no long* this article was reproduced with permission from the bmj group. it was first published in the british journal of sports medicine 2012;46:193-197 (originally published online 4 january 2012). mailto:nickwebborn@sportswise.org.uk 118 sajsm vol. 24 no. 4 2012 term follow-up. few studies adequately examine the possible ltcs of sport participation after the competitive period has been completed.26 to more usefully develop injury prevention that is sport-specific, the governing bodies and researchers need to consider a lifetime injury prevention model that takes into account a number of different factors because the strategies employed for prevention may be different at different stages of an athlete’s career. consequently, in the lifetime of a competitive athlete, we need to consider a number of different factors when performing injury surveillance if we are to address the risks across the full range of a sport’s participants. age growth-related injuries injuries that occur in the immature skeleton produce different pathologies than in the adult skeleton. bone growth precedes muscle, tendon and neural lengthening and consequently young sportspersons become neuromuscularly tight during peak growth spurts. this can result in different responses to acute and overuse injuries. however, this often tends to coincide with high levels of sport participation when there may also be an intense competition for the selection for sporting excellence; for example, academy selection. injuries occurring at this time may limit the progression into a full-competitive career. understanding the risk factors implicated in injuries in this age group would particularly be relevant to the sport academy setting. it is not just about the significant investment in these young players, injury prevention is also important to enable continued physical activity for life.27 identifying the most common injuries that stop young players achieving their potential, and trying to prevent them, is a responsible healthcare and cost-effective for club and the healthcare system. adult-onset injury many people develop their sporting interest later in life. maybe they were not the talented ones at school age, or were not given the opportunity or environment to develop within a structured system. once they become independent adults, they may choose a sporting activity with little experience in training practices, equipment choices or coaching. the mature sportsman has different patterns of injury. for example, the rupture of the achilles tendon occurs most frequently from 30 to 39 years, which is not the time of maximum sport participation, but we do not understand why this occurs at this time.28 in the older adult, progressing sarcopaenia and disuse atrophy may not just reflect the natural ageing process but be a consequence of a reduction in the physical activity. this may influence injury risk in the older adult.29,30 when people reach the age of retirement, they may have the time and the finance to take up activities they did not do in their working life. little is known about this age group, but we need to preserve the ability to maintain an active lifestyle to minimise the health risks of sedentary behaviours. do the injuries that occur in a particular sport in this older age group differ between those who have been active across their lifetime and those who have not? does this mean that we need different prevention and treatment strategies across this group? understanding that different injuries may occur in different age groups is important for athlete and coach education, and injury management. skill acquisition injuries (sais) athletes are susceptible to certain injury patterns in their sport as a consequence of the biomechanical requirements of that sport. in order to become technically proficient, they need to acquire the skills of their sport through repeated practice. we all have to go through a period of learning and at this point are likely to be vulnerable to injury, irrespective of our age, while we develop the mechanical efficiency for injury resilience.31 good coaching is integral to that process but not everyone is exposed to that benefit. across our lifetime, we may start and stop many sports or activities, and at each point of learning the new skill we become vulnerable to different injury types. we need also to be aware that sais can occur in mature athletes and not just the young, as many people take up different sports in later life. consequently, we need to be able to distinguish age-related factors from skill acquisition factors in good sports injury surveillance. it is also not uncommon in the present times for athletes to change sport even at an elite level (e.g. rebecca romero – great britain rowing to cycling, sarah storey – paralympic swimming to cycling). while these athletes will have the knowledge of how to be an elite athlete, they still need to acquire the technical skill and experience for the new sport. during this period, they may be more vulnerable to injury even though performing at an elite level. the level of skill is also important. for example, the top-level tennis player does not regularly have a ‘tennis elbow’, unlike the beginner or technically poor exponent of the sport.32 however, each elite athlete has gone through a learning phase of acquiring the skills of their sport. faulty technique, poor conditioning, recovery or training practices may lead to certain injury patterns which may stop the athlete progressing in the sport. consequently, the skill level is an important risk factor and may determine the type of injury incurred when playing the same sport. in cricket, the high incidence of spondylitis in young cricket bowlers prompted the studies of the technical action. the ‘front-on’ versus ‘side-on’ versus ‘mixed’ bowling actions were considered, but many factors were identified making it difficult to ascertain which were the most significant.33-36 performance-related injuries in an elite sport, much of our attention is focused on returning the athlete to the field of play as soon as possible and published research in an elite sport is less common.19 this may be for the reasons of data protection or because of the relatively small sample sizes, but understanding why our top athletes become injured, and finding ways to prevent this, is important. the cost of an expensive athlete sidelined for many months is something no professional employer wishes to bear and so prevention and better management of injury are essential.37 however, in this instance, it can be ‘return to play’ that is the key driver and not necessarily the long-term health of the athlete. additionally, the evidence is less clear on the risk of re-injury on return to play and also how the imaging results relate to the functional capacity. clearly, one of our roles in an elite sport is to keep the best athletes available for selection as often as possible, while also being mindful of the ltcs. however, this may be difficult in the face of managerial and financial pressures. career-ending injuries the end of a sportsperson’s career through injury is regrettable at whatever stage they might be: whether this is a talented youngster or a veteran athlete. it should be one of our duties in sports medicine to help identify the most common of these injuries and help prevent them through better coaching, conditioning or injury management, or to help advise those who regulate the sport on how to make it safer. these injuries may be acute catastrophic injuries or accumulated trauma. sajsm vol. 24 no. 4 2012 119 in the example of anterior cruciate ligament rupture, it is usually the consequent articular cartilage injuries that lead to the premature end of an athlete’s career, rather than the instability of the knee.38 for the athlete, there is a massive sense of loss; a lack of a career fulfilled or hopes dashed. there may be financial compensation through insurance schemes, but this is not the case in all sports. in some countries, data from insurance schemes can help identify the most common causes of medical retirement from a sport.39 can we prevent other athletes from developing the same problems? unfortunately, the lack of data appears to be partly a result of a lack of investment in sports medicine research. if long-term follow-up on retired athletes by each sport became mandatory, then the funding would have to be made available. long-term consequences we enter into a sport fear-free and for the enjoyment that it brings us. we do not consider the potential hazards and the possible lifechanging possibilities that may lie in wait. in 1980, at the age of 24, i incurred an incomplete tetraplegia from a rugby tackle that would affect and shape the rest of my life. the year i spent in rehabilitation in the spinal injuries unit it led me to meet 10 other people also injured that year with a similar injury. the prevalence of spinal injury at this time prompted an examination of the laws of the game and i joined the newly created rugby football union injuries working party that helped bring about recognition of the issue, a change in the laws and subsequently an injured players fund to help support those injured in the sport.4,40 but catastrophic injury is not the only important factor. long-term participation in physical activity is necessary for health maintenance.4 we cannot store up the health benefits of an active early life; it has to be lifelong. injury acquired earlier in life through a sport may prevent regular physical activity later. consequently, the prevention and better treatment of injuries that limit physical activity in the long-term are essential so that we can remain active in later life. the risk of participation in a sport needs to consider the potential impact on the future health also. training volume generally, the higher the level of performance, the higher the level of participation, but many enthusiastic amateurs also have high levels of participation without high skill level. we are typically weak in sports medicine at documenting the risk of injury per hours of training and competition to understand the relative risk of participation in different sports.41 sudden changes in the volume of training have been associated with certain overuse injuries which may be more important than the total volume of training in certain activities, and this may be sport-specific. we need to understand these relationships more clearly to attribute injury risk. in wheelchair racing, for example, there did not appear to be any difference in the frequency of injury between elite and non-elite athletes.42 the training variables of the distance pushed per week, the number of weight training sessions, or the length of time the athlete had been involved in wheelchair racing, were not associated with an increased risk of injury. high levels of participation in a sport may not be the risk factor but the history of how you reached that level may be. co-existing impairment co-existing impairments may be a contributory factor in injury risk and paralympic athletes are a prime example of this. we need to ensure that such data are not misleading. in several studies of injury in paralympic athletes, the subjects have been classed as ‘wheelchair athletes’.43,44 this can be a confusing terminology for assessing the injury risk from a prevention perspective. first, many wheelchair sports are technically and biomechanically quite different despite using a wheelchair for the sport; for example, wheelchair racing versus wheelchair basketball versus wheelchair fencing. second, within each sport, there may be different levels of impairment type; for example, spinal cord injury or a mixture of impairment types competing in the same sport. there may also be, for example, an amputee athlete who walks unaided with a prosthesis but removes it to participate in their sport in a wheelchair. finally, there are those athletes who use a wheelchair for daily mobility but come out of the wheelchair for sport participation; for example, swimming or powerlifting. in these cases, the specificity of the impairment type and sport is essential to truly understand the risk factors and prevention strategies. summary by using an approach that considers all these factors, we can start to develop models of the understanding of injury risk at different life phases and the levels of participation in a specific sport. in this way, when we talk about the risk inherent in sport participation, it is relevant to the particular sport, the level of participation, skill, age and the potential future health consequences. it poses the following questions for sports physicians, healthcare providers and educators generally and for the governing bodies of sports to address in a systematic fashion. each sport will generate its own model based upon the following: • what are the most common injuries that occur in the sport: • during growth and development • in athletes new to the sport (sais) • in experienced competitive athletes? • what are the most common career-ending injuries? • what are the long-term health consequences of participation in the sport? • is the pattern of injuries the same in elite and recreational athletes for each of the above? the key aspect of this approach is that we try to determine the significant injury issues over the individuals’ lifetime participation in a sport that allows us to define the areas of further detailed research as outlined by meeuwisse.16 each sport model will include these variables but the timeline will be specific to the sport. for example, the time profile of gymnastics would be very different to distance running. in this way, each sport would develop an ongoing process of evaluation of these questions (fig. 1) that would influence coach fig. 1. possible sport model showing frequency tables of injuries by type over the timeline of participation. 120 sajsm vol. 24 no. 4 2012 education, training principles, equipment factors and management strategies based upon the targeted need. improving safety in a sport can then be monitored on a systematic basis. published epidemiological studies show that our knowledge is generally patchy and quite variable across different sports.41,45 as a member of a working party and the co-author of one effort to make sport safer in the uk, i was disappointed that despite the importance of the issue, most of the recommendations were not adopted.46 it can be a lack of political will or funding that stops these issues being taken seriously and carried forward. as a sports medicine community, as a medical community and as a community generally, we need to address these issues in a structured and proactive way for the greater good before we are forced into defensive actions by a litigious society. sport is wonderful, sport is inspiring and sport is liberating but it can result in significant harm to health. let us commit to making it safer through collaboration, organised research and working with governing bodies rather than by legal process. it is interesting to consider the text on a website with regard to mesothelioma: ‘being exposed to asbestos is not your fault. you may have been put in harm’s way because of a previous job, a careless employer, or a negligent manufacturing company.’47 so experiencing the consequences some years after professional sport participation may not limit the employer’s liability if inadequate precautions were taken. did the employer assess the risks of sport participation? did they provide appropriate information? did they take adequate preventive measures? interestingly, a google search for ‘mesothelioma lawyer’ brought 436 000 results but more alarmingly a search for ‘sports injury lawyer’ brought a massive 1 040 000 results. it is likely that we will see an increasing number of litigation cases seeking compensation for long-term health problems from sports injury. the full extent of the impact on health may not necessarily have been evident at the time of leaving the sport. will professional athletes who develop long-term health consequences from sport participation, without prior warning of the risks, become the industrial disease claimants of the future? will it be litigation that pushes forward sports injury surveillance or should we be proactive in adopting new models that produce greater clarity of the issues and guidance on how to resolve them? to prevent this, we must encourage sports governing bodies to take a lead in establishing a lifetime model of the injury occurrence, in professional and amateur levels, specific for their sport. sports medicine researchers must work with them to look at causation, prevention, management and long-term health as an ongoing process with a continued drive to reduce the incidence and severity of injury. once a sport-specific model is established, there can be improved guidance for coaches and healthcare professionals, but moreover the governing body, as an employer, will be meeting its requirements for professional sport and also meeting its ethical responsibility. acknowledgments. the author thanks dr polly baker and stephanie anderson for proof-reading, comments and encouragement. competing interests. none. provenance and peer review. not commissioned; externally peer reviewed. references 1. marshall sw, guskiewicz km. sports and recreational injury: the hidden cost of a healthy lifestyle. inj prev 2003;9:100-102. 2. conn jm, annest jl, gilchrist j. sports and recreation related injury episodes in the us population, 1997-99. inj prev 2003;9:117-123. 3. department for culture, media and sport/strategy unit. game plan: a strategy for delivering government’s sport and physical activity objectives. london: department for culture, media and sport/strategy unit, 2002. 4. department of health. at least five a week: evidence on the impact of physical activity and its relationship to health. london: department of health, 2004. 5. shephard rj. can we afford to exercise, given current injury rates? inj prev 2003;9:99100. 6. treisman gj, clark mr. a behaviorist perspective. adv psychosom med 2011;30:8–21. 7. podlog l, dimmock j, miller j. a review of return to sport concerns following injury rehabilitation: practitioner strategies for enhancing recovery outcomes. phys ther sport 2011;12:36-42. 8. bianco t, malo s, orlick t. sport injury and illness: elite skiers describe their experiences. res q exerc sport 1999;70:157-169. 9. alarp “at a glance”. http://www.hse.gov.uk/risk/theory/alarpglance.htm (accessed 6 july 2011). 10. lohmander ls, ostenberg a, englund m, et al. high prevalence of knee osteoarthritis, pain, and functional limitations in female soccer players twelve years after anterior cruciate ligament injury. arthritis rheum 2004;50:3145-3152. 11. von porat a, roos em, roos h. high prevalence of osteoarthritis 14 years after an anterior cruciate ligament tear in male soccer players: a study of radiographic and patient relevant outcomes. ann rheum dis 2004;63:269-273. 12. roos h. are there long-term sequelae from soccer? clin sports med 1998;17:819–31, viii. 13. roos h, lindberg h, gärdsell p, et al. the prevalence of gonarthrosis and its relation to meniscectomy in former soccer players. am j sports med 1994;22:219-222. 14. lindberg h, roos h, gärdsell p. prevalence of coxarthrosis in former soccer players. 286 players compared with matched controls. acta orthop scand 1993;64:165–167. 15. van mechelen w, hlobil h, kemper hc. incidence, severity, aetiology and prevention of sports injuries. a review of concepts. sports med 1992;14:82-99. 16. meeuwisse wh, tyreman h, hagel b, et al. a dynamic model of etiology in sport injury: the recursive nature of risk and causation. clin j sport med 2007;17:215-219. 17. meeuwisse wh. assessing causation in sport injury: a multifactorial model. clin j sport med 1994;4:166-170. 18. hägglund m, waldén m, bahr r, et al. methods for epidemiological study of injuries to professional football players: developing the uefa model. br j sports med 2005;39:340346. 19. ekstrand j, hägglund m, waldén m. injury incidence and injury patterns in professional football: the uefa injury study. br j sports med 2011;45:553-538. 20. hägglund m, waldén m, ekstrand j. uefa injury study–an injury audit of european championships 2006 to 2008. br j sports med 2009;43:483-489. 21. brooks jh, kemp sp. injury-prevention priorities according to playing position in professional rugby union players. br j sports med 2011;45:765-775. 22. sankey ra, brooks jh, kemp sp, et al. the epidemiology of ankle injuries in professional rugby union players. am j sports med 2008;36:2415-2424. 23. fuller cw, ashton t, brooks jh, et al. injury risks associated with tackling in rugby union. br j sports med 2010;44:159-167. 24. kemp sp, hudson z, brooks jh, et al. the epidemiology of head injuries in english professional rugby 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paraplegia 1985;23:170-175. 44. ferrara ms, davis rw. injuries to elite wheelchair athletes. paraplegia 1990;28:335–41. 45. murphy df, connolly da, beynnon bd. risk factors for lower extremity injury: a review of the literature. br j sports med 2003;37:13-29. 46. department of culture, media & sport. sport in the uk – improving safety and medical provision, 2002. 47. your legal rights and options. http://www.mesolawsuit.com (accessed 7 july 2011). http://www.mesolawsuit.com km_c227-20180517092518 34 sajsm vol 24 no. 2 2012 editorial conferences – do they still serve a purpose? methods of communicating new information have undergone a rapid change. twenty years ago it was important to go to conferences to remain at the cutting edge of a discipline or specialty. new information was presented at conferences, often months or years before it appeared in print. experts in the field were invited to present exhaustive overviews on a topic. other researchers presented their research findings in either oral or poster presentations. a prerequisite was that the data had not been presented or published before. in this era it was tantamount to professional suicide if you missed a major conference. conferences stimulated new ideas and ensured that as a scientist or practitioner, one stayed abreast of the trends and new findings in a field. the role of the conference has been challenged with the development of the internet. now communication can occur instantaneously with anyone, anywhere, anytime in the world. discussions on any topic can occur through online blogs. professional hierarchy, which often existed at conferences, disappears in a cyberspace forum. youtube videos describing a procedure or new treatment technique can be made on a mobile phone and uploaded immediately. in short, communication has never been easier. despite the current easy access to information, conferences have stood the test of time. delegates are prepared to pay in the region of r25 000, all things considered, to attend an overseas conference. why, with the easy access to information, is there still the need to go to conferences? when faced with this question the usual knee-jerk response is that conferences provide an opportunity to meet peers and establish collaborative relationships. it is an established fact that highly connected collaborative networks have the capacity to innovate better than researchers working in an isolated environment. attending a conference fosters new relationships and develops new relationships, something that cannot be done effectively at a distance using communication via the internet. conference organisers are starting to realise this and design conferences with more breakaway groups, more interactive symposia and more social functions. alumni groups often meet at conferences, as do editorial boards of journals and members of international working groups. the academic presentations are almost an excuse for scientists and practitioners to be able to get together and establish working relationships. however, not everyone shares the viewpoint that conferences have a consistently positive purpose. john ioannidis writes that the wholesale acceptance of conferences is questionable.1 from a holistic perspective the cost of a conference to the planet is excessive – it has been estimated that the airline fuel carrying participants around the globe to a typical international conference amounts to an environmental burden of about 10 000 tons of carbon.1 he also questions the quality of data presented as short communications at conferences. academics have to submit abstracts to the conference to qualify for funding from their institutions. conference organisers make this easy by having limited peer review of the abstracts and encourage submission to boost numbers (and profit margins). even if a conference does have peer review for the acceptance of the abstract, an abstract of questionable standard can slip through because the quality of the research can be masked by a well-written abstract. this is borne out by the fact that most abstracts presented at conferences are not converted to full peerreviewed papers. the viewpoint of ioannidis certainly has merit and should be considered next time a decision is made about the pros and cons of attending an upcoming conference. this edition of the journal has a variety of original research papers, a case study and a commentary. enjoy the read! mike lambert editor-in-chief 1. ioannidis jpa. are medical conferences useful? and for whom? jama 2012;307(12):1257-1258. sajsm 565_this one.indd original research 4 sajsm vol. 27 no. 1 2015 background. footscan technology allows for assessment of injury risk and walking mechanics, yet there is a dearth of normative data pertaining to the normal, injury-free foot in a south african (sa) context. objective. to generate normative tables from plantar pressure pro�le data gathered from students at an sa university. methods. �e rs footscan (rsscan, belgium) system was used to measure the plantar pressure values of the foot. ten anatomical landmarks of the foot were analysed: the hallux, lateral toes, �ve metatarsal heads, midfoot, and medial and lateral heel. �ese ten areas were grouped into one of three regions: forefoot, midfoot and heel. a total of 180 participants were subdivided as follows: gender (males, n=90; females, n=90); race (black, n=60; white, n=60; coloured, n=60). each race group comprised 30 males and 30 females. results. of the ten individual plantar pressure areas, the second and third metatarsal heads demonstrated the highest mean peak plantar pressure values. of the three regions, the heel region was ascribed with the largest plantar pressure values. black females, coloured males and coloured females yielded the highest pressure values, especially under the midfoot region of the foot. black and white males and white females exhibited the lowest pressure under the foot, especially under the midfoot region. conclusion. �e plantar pressure pro�le data generated in this study could serve to provide clinicians with a frame of reference when evaluating participants within the age range of 18 30 years. s afr j sports med 2015;27(1):4-11. doi:10.7196/sajsm.565 dynamic plantar pressure pro�les of south african university students m kramer,1 ma, ba (hms) hons (biokinetics), phd; r du randt,1 phd; d venter,2 phd 1 department of human movement science, school of lifestyle sciences, nelson mandela metropolitan university, port elizabeth, south africa 2 department of statistics, school of computer science, mathematics, physics and statistics, nelson mandela metropolitan university, port elizabeth, south africa corresponding author: m kramer (mark.kramer2@nmmu.ac.za) the literature is extensive with information and research on the key factors affecting foot pressure and foot structure during dynamic activities such as walking and running, including gender, race, age, height, weight, body mass index, walking speed and physical activity.[1-6] however, internationally, there is a dearth of reference data pertaining to normal, injury-free population groups. �is is compounded by the general absence of normative data and a lack of controlled, structured and standardised procedures for clinical pro�les across diverse gender and race groups. �e structure and function of the foot is of critical importance during weight-bearing activities, such as walking, running, jumping and cycling.[7] �is is primarily because the entire lower extremity composes a closed kinetic chain; therefore, a change in foot and ankle structure has an e�ect not only on the foot and ankle, but also on superincumbent joints such as the knee, hip and lower back.[8] a change in dynamic foot structure and subsequent foot pressure may therefore lead to a higher incidence of injury.[1,4,8,9] research has demonstrated that the most common joint injuries sustained are those of the ankle and knee, and that these injuries occur mostly in the 15 24-year age category, especially in the male population (1.53/1 000 person-years).[9-11] interestingly, waterman et al.[10] found that, among other factors, more than half of ankle injuries were attributed to stair falls or walking on a level surface; the remainder was attributed to athletic activities. in the same study, it was established that black and white race groups were associated with substantially higher incidence rates of injuries compared with coloured population groups, with most injuries in the male population.[9] �e potential risk of injury related to foot and ankle biomechanics is a reality whether during activities of daily living or athletic endeavours. �is substantiates the importance of accurately and reliably measuring plantar pressure values of normal, injury-free population groups in order to establish reference data for clinical settings. reference tables would serve to provide clinicians and practitioners with the tools to define patients into appropriate categories and possibly identify those participants with a higher propensity for injury. �e present study was therefore initiated to help address this need by determining plantar pressure pro�les of a normal, injury-free student population representative of a south african (sa) university. method a total of 180 participants (90 male, 90 female) were recruited for the present study through the university’s intranet network and posters. participation was voluntary and anonymous. �e research ethics committee of the university granted approval for the study (rec-h: h10heahms003). �e mean (standard deviation (sd)) anthropometric data of the group were: age 22.2 (2.9) years; weight 67.0 (12.0) kg; height 169.7 (8.9) cm; and body mass index (bmi) 23.2 (3.2) kg.m-2. there was a total of 30 male and 30 female participants per representative race group (black, white and coloured). for inclusion in the present study, participants had to be between the ages of 18 and 30 years, have no history of lower sajsm vol. 27 no. 1 2015 5 extremity injury or surgery, and fall within a bmi range of 18.0 30.0 kg.m-2. four data-collecting instruments were utilised in the study, namely the completion of a questionnaire, and measurements of height, weight and plantar pressure. � e questionnaire obtained biographical information and medical history. � e questionnaire helped to identify participants not suitable for the study. height measurements were performed using the holtain stadiometer (holtain ltd, uk); weight measurements were taken using the calibrated scalemaster medical electronic scale (weigh tech co. ltd, china). the equipment used for the purposes of plantar foot pressure measurement was the rs footscan system (rsscan, belgium). the latter system runs on a data acquisition frequency of up to 500 hz as subjects perform trials at a walking pace. walking speed was controlled for by using timing gates; therefore, only trials that fell within the speed limit of 1.3 1.5 m.s-1 were saved for analysis. initial contact would be identi� ed by the force plate when at least three sensors were activated at a resultant force level of >5 n (as per user manual for rs footscan). a 12-bit analogue-to-digital (ad) conversion was used, thereby providing each sensor with a resolution of 0.5 n and a maximum measuring range of 1 127 n/cm-2. participants performed five trials to familiarise themselves with the equipment and the testing procedure (fig. 1). a total of 10 successful walking trials per participant was then recorded and saved for analysis. each trial yielded three footprints, thus a total of 30 footprints (15 le� feet and 15 right feet) were used for analysis per participant. left and right foot data were included to assess gait symmetry; discrepancies between values obtained for the left and right feet could indicate clinical relevance. the rs footscan software divides the footprint into ten anatomical areas for analysis, namely the hallux (great toe), lateral toes, metatarsal 1 5, midfoot, medial heel and lateral heel. a complex algorithm places these ten sensor areas of equal size at predetermined areas of the recorded footprint, which may not always be entirely accurate (fig. 2a), requiring the adjustment of sensor recording to be executed manually for each of the ten anatomical areas for each footprint for all participants (fig. 2b). each change recorded was saved to represent more accurately the ten anatomical landmarks. � ese ten anatomical landmarks were then further grouped into three categories, namely the forefoot, midfoot and heel to allow for comparison with the literature, and for ease of reference in terms of foot structure (fig. 2b). � e forefoot category comprised the hallux, lateral toes and all � ve metatarsal sensors, the midfoot category comprised the midfoot pressure sensor only, and the heel category comprised the lateral and medial heel sensors (fig. 2). although pressure values are expressed as n.m-2, this study, as well as most others, represented plantar pressure values as n.cm2 owing to the small size of the sensors and anatomical landmarks.[5,12] to meet the primary objective of the present research, reference data in the form of stanine tables (based on a normal distribution) were established for plantar pressure values for each gender and race group. stanine scores were ranked from lowest to highest: 1 (extremely low), lowest 4%; 2 (very low), next 7%; 3 (low), next 12%; 4 (below average), next 17%; 5 (average), next 20%; 6 (above average), next 17%; 7 (high), next 12%; 8 (very high), next 7%; 9 (extremely high), last 4%. results gender-race pressure pro� les � e plantar pressure data of all 180 par ticipants were gathered and analysed to establish normative data in the form of stanine tables for each gender-race group. tables 1 and 2 indicate the plantar pressure values for males and females, respectively, for each of the race groups, with plantar pressure values being classi� ed into speci� c stanine categorisations. plantar pressure fig. 1. rs footscan protocol set-up. fig. 2. placement of sensors and regional foot classi� cation: a. before adjustment; b. a� er adjustment. a b 6 sajsm vol. 27 no. 1 2015 values (expressed in n.cm2) are provided for the left and right feet for each gender-race group. each stanine rating represents the limit between one rating and another; therefore, in order to score a higher rating, a participant would have to obtain a higher score than that set by the speci� c stanine cut-o� . for example, with regard to black males, values between 8.629 and 11.338 n.cm2 for right toe 1 would be considered average, whereas values between 11.339 and 12.882 n. cm-2 would be considered above average. gender-race regional pressure pro� les in addition to the 10 anatomical areas loaded during walking, the foot may also be classi� ed according to speci� c regions, namely the forefoot, midfoot and heel (fig. 2). classifying plantar pressures in this manner allows for greater correlation to more diverse literature, as plantar pressure loading may be linked to the gross region of the foot that is loaded as opposed to the specific anatomical area.[13] the forefoot, midfoot, heel and whole-foot regions are highlighted in table 3. the stanine categorisations are given relative to each gender group (male and female), each race group (black, coloured and white), and each gender-race group (black female, coloured female, white female, black male, coloured male and white male). the mean peak plantar pressure values, together with the sds, for each region of the le� and right feet are illustrated in figs 3 and 4, respectively. these figures provide an overview of the pressure differences between the various gender-race subgroups, in addition to the regions of the foot that exhibit the highest or lowest mean peak pressure values. discussion � e reality of gender and racial diversity in sa substantiates the requirement for both gender-specific and race-specific plantar pressure pro� le data. although di� erences in plantar pressure pro� les have been observed between gender and race groups, the causes thereof have yet to be established in an sa context. � e establishment of genderand race-specific plantar pressure profile data would provide clinicians with the necessary information to make more accurate comparisons and assessments, and therefore ultimately to make more precise diagnoses and recommendations to minimise the risk of potential injury. � e present study found that the heel and forefoot regions yielded the highest pressure values, whereas the midfoot yielded the lowest. � is can be understood in terms of the biomechanical concepts of pronation and supination, the degree of which determines the plantar pressure distribution under the various areas of the foot.[8,13] in the case of pronation, the midtarsal bones tend to unlock the subtalar joint, which in turn causes the cuboid and navicular bones to become more parallel, allowing the forefoot and midfoot to unlock.[13] although the latter is necessary for effective shock absorption of ground reaction forces during gait, it becomes problematic in the case of overpronation, where the forefoot does not resupinate in time for toe-off, thereby exerting markedly higher pressure values under the midfoot and forefoot regions. owing to the biomechanics of gait and various muscle activation patterns, the centre of mass of the participant should move over the medial metatarsals and � rst ray (� rst cuneiform and � rst metatarsal) during toe-o� , as these structures are designed to bear the greatest loads.[8,13] in a more pronated foot structure, the medial longitudinal arch becomes more mobile, resulting in longer loading times and thus higher pressure values. [8] under these 40.00 30.00 35.00 25.00 20.00 15.00 10.00 5.00 0.00 forefoot midfoot heel foot female black female white female coloured male black male white male coloured foot region pr es su re (n /c m 2 ) fig. 3. le� foot pressure data. 40.00 30.00 35.00 25.00 20.00 15.00 10.00 5.00 0.00 pr es su re (n /c m 2 ) forefoot midfoot heel foot foot region female black female white female coloured male black male white male coloured fig. 4. right foot pressure data. sajsm vol. 27 no. 1 2015 7 dpr toe 1  3.49 4.10 5.15 8.63 11.34 12.88 16.21 18.06 toes 2 5  0.41 0.57 1.05 1.87 2.67 3.40 4.49 5.63 meta 1 4.63 4.91 5.94 7.64 10.19 12.16 17.14 19.12 meta 2 8.47 10.60 12.65 16.55 17.83 19.94 22.57 23.05 meta 3 10.05 11.79 13.41 16.92 19.93 23.19 26.74 29.66 meta 4 6.96 7.62 8.64 10.88 13.61 15.94 19.77 21.29 meta 5 2.06 2.76 3.49 4.00 6.39 7.31 8.75 10.07 midfoot 1.50 1.64 1.91 2.40 3.00 3.95 4.02 5.34 medial heel 8.89 10.44 11.93 13.31 16.43 18.15 20.64 23.94 lateral heel 7.56 7.87 9.10 11.35 13.48 15.06 16.21 20.32 dpl toe 1 2.61 3.34 5.19 6.24 8.47 10.33 12.15 16.18 toes 2 5 0.31 0.49 0.86 1.41 1.98 2.53 3.67 5.93 meta 1 3.99 5.33 5.80 6.83 8.07 9.86 13.03 15.39 meta 2 9.97 11.49 12.31 14.29 16.29 20.30 21.27 22.92 meta 3 14.38 16.00 16.57 19.66 22.71 26.42 27.92 30.79 meta 4 8.58 10.29 13.74 15.68 17.24 19.16 22.88 31.17 meta 5 2.84 3.90 4.13 4.90 8.34 11.47 13.79 14.80 midfoot 1.44 1.97 2.36 2.87 3.48 4.45 4.70 6.16 medial heel 7.97 8.87 12.07 13.59 16.22 18.94 20.74 25.12 lateral heel 6.48 7.86 9.50 11.58 14.18 15.53 16.26 20.24 coloured male dpr toe 1 2.69 3.44 5.93 8.43 12.12 20.38 24.69 37.86 toes 2 5 0.47 0.49 0.96 2.09 2.63 3.89 4.71 7.22 meta 1 4.35 4.92 6.34 7.49 14.90 18.27 26.05 31.36 meta 2 7.44 10.41 15.01 18.28 24.10 29.07 36.05 42.30 meta 3 6.29 10.12 14.94 20.81 23.18 26.29 27.79 47.37 meta 4 3.44 7.78 10.18 11.28 14.00 17.75 22.79 30.08 meta 5 1.78 2.64 4.03 4.96 7.07 8.03 11.23 13.31 midfoot 0.87 1.15 1.60 2.41 3.13 4.72 14.12 19.27 medial heel 6.48 10.92 15.20 17.99 23.43 33.47 52.29 57.28 lateral heel 6.05 8.01 11.83 14.83 19.40 22.47 27.43 43.72 dpl toe 1 2.32 6.48 8.28 9.18 12.81 26.74 34.46 49.73 toe 2-5 0.31 0.61 1.25 2.10 2.60 4.55 5.20 9.64 meta 1 3.51 4.44 6.52 9.03 13.62 14.38 24.07 25.85 meta 2 8.04 10.29 13.76 19.14 22.69 25.45 28.91 38.85 meta 3 9.62 13.57 16.01 19.85 24.28 28.22 31.28 42.28 meta 4 4.76 8.05 10.50 12.39 15.37 18.23 22.32 23.71 meta 5 0.98 2.53 3.87 4.86 6.90 9.26 13.09 14.60 midfoot 0.88 1.26 2.28 2.98 4.23 6.76 10.16 18.83 medial heel 7.95 9.45 16.51 19.85 25.30 27.96 49.20 56.76 lateral heel 6.28 7.18 11.93 15.95 21.36 23.12 34.72 39.75 white male dpr toe 1 5.38 5.88 7.10 9.67 12.80 14.74 20.41 22.42 toes 2 5 0.65 0.87 1.71 2.30 2.63 3.50 4.84 6.11 meta 1 3.75 4.80 7.77 9.95 15.68 17.81 19.72 23.59 meta 2 6.40 12.19 16.69 18.28 21.35 24.92 28.60 30.77 continued ... table 1. reference value stanines for male plantar pressure values for le� and right feet black male extremely low very low low below average average above average high very high extremely high 8 sajsm vol. 27 no. 1 2015 circumstances, the cuboid bone, which acts as a pulley for the peroneus longus on the lateral aspect of the foot, cannot fulfil its function of stabilising the �rst ray, resulting in increased pressures under the other metatarsals.[7,8] the plantar pressure profile values generated are of particular interest with regard to race, as it was found that black participants demonstrated statistically and practically signi�cant higher pressure values under the forefoot when compared with white (t=0.000, p<0.05, d=0.78) and coloured (t=0.026, p<0.05, d=0.35) participants. with regards to the midfoot region, white participants demonstrated statistically and practically signi�cant lower values compared with black (t=0.003, p<0.05, d=0.94) and coloured (t=0.02, p<0.05, dpr toe 1 7.70 9.08 14.68 16.51 24.99 31.65 37.33 48.22 toes 2 5 0.25 0.80 1.97 3.15 4.25 8.48 10.14 15.37 meta 1 6.95 9.23 12.46 14.94 17.62 27.07 31.04 32.13 meta 2 19.96 21.11 24.88 29.16 40.49 48.29 51.59 53.79 meta 3 20.16 22.84 25.29 31.12 40.28 45.46 50.19 54.57 meta 4 7.33 15.18 17.33 21.34 25.24 30.55 33.30 44.63 meta 5 4.35 6.03 7.41 8.94 14.02 21.83 26.00 31.60 midfoot 1.69 2.51 3.41 4.10 5.15 6.94 8.74 14.06 medial heel 18.72 20.85 23.95 28.71 32.13 38.03 39.06 41.64 lateral heel 13.75 14.85 16.72 19.15 23.15 24.25 29.46 32.04 dpl toe 1 3.92 8.63 13.57 17.37 24.38 33.23 39.85 50.74 toes 2 5 0.88 1.03 1.36 3.00 4.94 5.84 8.18 11.64 meta 1 8.05 9.65 11.43 13.02 16.90 19.74 22.53 31.42 meta 2 15.48 20.19 23.26 29.18 34.38 39.38 43.49 46.06 meta 3 19.51 27.97 30.16 34.98 42.36 46.47 51.74 53.89 meta 4 9.34 13.29 20.22 24.41 29.82 32.59 36.04 40.01 meta 5 5.18 6.70 8.98 12.96 18.10 20.66 28.43 39.70 midfoot 1.35 1.60 2.50 3.68 4.32 5.50 7.02 10.61 medial heel 14.20 17.20 19.80 22.89 25.07 28.87 30.75 36.76 lateral heel 17.13 20.22 23.41 24.86 29.13 33.57 36.14 42.98 continued ... meta 3 6.86 15.90 17.11 19.27 21.96 23.01 26.16 28.13 meta 4 3.90 8.08 8.71 10.84 12.32 13.69 15.27 16.01 meta 5 1.75 2.18 3.06 4.08 5.88 6.87 7.88 10.88 midfoot 0.27 0.81 0.98 1.58 2.33 2.76 2.95 4.11 medial heel 8.81 15.38 17.41 20.58 22.64 24.64 27.18 30.14 lateral heel 6.00 11.03 14.65 15.88 17.78 21.26 22.64 24.26 dpl toe 1 3.03 5.15 6.79 8.08 10.33 15.34 17.38 19.58 toes 2 5 0.27 0.38 0.75 0.89 2.29 2.65 4.11 7.08 meta 1 3.82 4.76 5.90 10.83 13.56 15.89 20.14 22.42 meta 2 6.93 12.39 14.63 18.93 22.59 24.53 28.14 29.04 meta 3 7.89 17.56 19.74 23.11 25.10 30.75 32.45 32.95 meta 4 6.47 7.17 11.50 13.58 15.50 17.33 18.62 22.91 meta 5 1.58 2.74 3.35 5.07 5.49 7.00 7.58 13.07 midfoot 0.59 1.30 1.58 1.94 3.08 3.95 5.52 7.63 medial heel 10.74 16.82 19.15 22.14 24.67 27.62 28.68 31.94 lateral heel 6.60 11.92 13.76 16.30 18.47 21.35 24.46 26.02 dpr = data pressure right; meta = metatarsal; dpl = data pressure le�. table 1 (continued). reference value stanines for male plantar pressure values for le� and right feet white male extremely low very low low below average average above average high very high extremely high table 2. reference value stanines for female plantar pressure values for le� and right feet black female extremely low very low low below average average above average high very high extremely high sajsm vol. 27 no. 1 2015 9 d=0.58) participants. �is may indicate greater amounts of pronation at the midfoot for black and coloured participants, whereas white participants may have a greater tendency to either underpronate or exhibit a higher arch proportional to other groups. �ese �ndings are in agreement with other similar research findings.[7,14] more speci�cally, the results depicted in tables 1 and 2 indicate that the largest mean peak plantar pressure values were recorded under the second and third metatarsal heads of both the le� and right feet for both black and white race groups, with only the magnitude thereof varying. �e coloured group was the exception here, with both the �rst toe and heel pressure data re�ecting higher values. the midfoot is often of great interest, as it indicates the dynamic behaviour of the foot.[15] midfoot pressure values have been variably established.[5,11] although reported values are dissimilar and indeed dpr toe 1 3.76 6.31 8.02 11.42 13.88 21.71 34.99 45.78 toes 2 5 0.47 0.63 1.20 1.79 3.67 4.57 7.58 12.24 meta 1 5.57 5.78 7.21 9.58 12.62 15.79 25.38 27.44 meta 2 7.68 12.49 15.18 19.52 22.57 27.12 30.49 38.31 meta 3 5.17 10.50 13.26 19.74 23.42 26.10 28.50 36.83 meta 4 3.17 6.43 8.67 11.72 15.68 16.17 21.92 28.77 meta 5 1.90 1.97 3.89 4.29 5.68 7.05 9.23 14.76 midfoot 0.65 0.83 1.16 2.30 3.75 4.09 5.19 6.09 medial heel 7.15 14.25 14.52 17.80 20.32 29.19 46.05 55.07 lateral heel 5.98 10.18 11.80 13.84 16.27 18.35 24.48 27.49 dpl toe 1 2.39 3.57 9.14 11.91 15.58 17.61 34.93 50.50 toe 2-5 0.25 0.83 1.07 1.67 2.73 3.67 4.30 7.41 meta 1 4.06 5.23 5.53 8.50 12.75 15.58 19.35 30.19 meta 2 7.83 11.46 13.95 16.43 21.32 26.61 32.79 38.61 meta 3 9.32 11.75 14.03 18.51 26.24 30.69 37.89 55.81 meta 4 4.48 5.95 8.86 10.08 16.65 21.69 29.74 41.07 meta 5 0.99 1.94 3.57 5.69 6.83 9.66 24.71 42.50 midfoot 0.66 0.83 1.45 2.88 3.99 4.77 5.40 6.05 medial heel 8.25 11.95 14.27 17.20 18.78 27.42 37.72 41.15 lateral heel 6.53 10.69 13.02 14.96 18.66 24.09 32.26 40.21 white female dpr toe 1 4.07 6.57 8.27 10.45 13.78 16.22 18.61 21.81 toes 2 5 0.56 1.19 1.39 1.99 2.81 4.14 5.83 6.55 meta 1 7.84 8.81 10.87 13.25 14.56 17.04 18.55 22.01 meta 2 12.98 14.18 15.39 19.17 24.05 28.18 31.29 32.92 meta 3 10.29 12.08 13.40 16.85 19.14 23.70 27.92 32.71 meta 4 4.07 5.39 6.45 7.64 9.92 13.25 14.80 16.32 meta 5 1.43 1.57 2.08 2.85 4.54 6.12 7.63 8.32 midfoot 0.53 0.87 1.12 1.57 1.94 2.55 3.70 4.65 medial heel 14.57 14.74 16.91 19.37 20.64 22.08 23.80 26.98 lateral heel 12.26 12.67 14.05 17.01 18.74 21.15 22.55 26.21 dpl toe 1 2.71 4.43 7.28 8.94 11.31 12.96 17.05 18.71 toes 2 5 0.28 0.47 1.02 1.74 2.71 3.28 5.00 6.02 meta 1 4.86 6.58 7.86 9.60 11.34 14.74 21.02 22.59 meta 2 13.13 16.10 16.72 18.18 21.39 24.80 27.31 28.06 meta 3 12.35 14.74 17.97 24.33 26.86 31.08 34.21 40.00 meta 4 7.25 8.04 10.50 12.44 14.58 16.17 18.89 23.42 meta 5 1.90 2.25 3.25 5.02 6.45 7.54 9.20 10.06 midfoot 1.34 1.54 2.07 3.11 3.66 4.28 5.45 6.45 medial heel 13.81 15.66 18.78 20.99 22.61 24.91 26.73 30.71 lateral heel 11.51 14.02 15.72 16.91 18.75 22.32 24.16 24.74 table 2 (continued). reference value stanines for female plantar pressure values for le� and right feet coloured female extremely low very low low below average average above average high very high extremely high 10 sajsm vol. 27 no. 1 2015 all 7.19 8.72 9.76 11.63 13.78 16.83 23.01 28.97 female 7.74 9.08 10.34 12.65 16.40 21.85 26.40 30.90 black 15.10 16.37 17.82 20.64 23.06 27.25 30.54 33.01 coloured 4.37 8.00 9.46 10.51 14.63 16.83 23.25 25.63 white 8.79 9.18 9.78 10.99 12.41 13.42 15.63 16.64 male 5.71 8.30 9.16 11.28 12.77 13.99 15.60 21.77 black 7.56 8.23 8.71 9.48 11.38 12.82 13.76 15.17 coloured 4.29 8.28 9.16 12.61 13.63 15.12 18.23 29.87 white 4.62 9.26 10.66 11.64 12.77 14.09 14.67 16.63 black 7.64 8.40 10.07 12.86 17.39 22.42 27.52 30.93 coloured 3.73 8.01 9.18 11.41 13.98 16.23 22.95 29.65 white 8.65 9.13 10.17 11.28 12.62 13.89 15.51 16.79 midfoot all 0.63 0.94 1.52 2.20 3.00 4.09 5.58 10.52 female 0.57 0.87 1.45 2.29 3.82 4.47 6.22 9.15 black 1.69 2.51 3.41 4.10 5.15 6.94 8.74 14.06 coloured 0.65 0.83 1.16 2.30 3.75 4.09 5.19 6.09 white 0.53 0.87 1.12 1.57 1.94 2.55 3.70 4.65 male 0.72 1.07 1.57 2.13 2.85 3.77 4.42 12.56 black 1.50 1.64 1.91 2.40 3.00 3.95 4.02 5.34 coloured 0.87 1.15 1.60 2.41 3.13 4.72 14.12 19.27 white 0.27 0.81 0.98 1.58 2.33 2.76 2.95 4.11 black 1.52 1.75 2.17 3.02 4.01 5.16 6.96 9.30 coloured 0.67 0.85 1.45 2.37 3.44 4.20 5.91 18.96 white 0.40 0.82 0.99 1.57 2.19 2.69 3.48 4.32 heel all 7.86 12.09 13.98 17.10 19.83 23.89 30.57 40.23 female 12.53 13.37 15.88 18.46 21.38 27.51 31.24 34.96 black 17.41 18.45 20.29 25.14 28.04 30.57 33.26 35.28 coloured 7.03 12.68 13.36 15.91 18.80 26.67 31.93 40.43 white 13.20 13.85 15.74 18.07 19.56 21.55 23.66 25.52 male 7.17 9.55 13.50 15.09 18.51 22.57 25.26 41.49 black 8.27 9.25 10.25 13.03 14.67 16.15 18.83 21.71 coloured 6.29 9.36 13.89 15.91 21.08 28.84 41.78 48.08 white 7.53 13.98 15.59 18.27 20.67 22.73 24.30 26.37 black 9.09 10.13 13.34 16.15 20.90 27.50 30.64 34.16 coloured 6.00 11.55 13.70 15.91 19.68 27.49 37.04 47.61 white 13.13 13.77 15.67 18.25 19.83 22.56 23.97 26.34 foot all 6.32 7.66 8.94 10.26 12.32 15.16 20.61 24.42 female 7.45 8.44 9.82 11.24 14.47 17.52 20.85 24.27 black 12.06 13.95 14.55 16.48 20.21 20.85 23.92 24.58 coloured 4.11 8.22 8.76 9.88 12.44 15.78 20.49 23.17 white 8.36 8.53 9.30 10.02 11.19 12.49 13.47 14.90 male 5.13 6.88 8.37 9.90 11.24 12.51 14.43 25.06 black 6.50 6.78 7.42 8.18 9.65 11.26 12.02 12.54 coloured 3.97 6.69 8.77 10.47 12.36 20.25 25.59 28.59 white 4.37 8.59 9.99 10.71 11.82 12.67 13.90 15.03 black 6.53 6.95 8.41 11.28 14.33 18.30 20.85 24.32 coloured 3.52 7.08 8.76 10.08 12.36 17.02 23.78 26.65 white 7.88 8.47 9.74 10.34 11.43 12.62 13.70 15.19 table 3. reference stanines for plantar pressure of all participants for all regions of the foot forefoot extremely low very low low below average average above average high very high extremely high sajsm vol. 27 no. 1 2015 11 substantially higher than those obtained in the present research, it is noteworthy that this is dependent on the gender and race groupings. this also reiterates the need for the establishment of normative data, as both higher and lower values are indeed present within a normal range. disparities pertaining to plantar pressure data may be attributable to differences in participant characteristics and testing methodology. what remains of interest, however, is that substantially lower pressure values were observed under the midfoot region compared with those of the forefoot or heel regions in the studies referenced earlier in this paragraph, as well as in the present study. the need for standardised testing and evaluation (such as the use of ten anatomical landmark sensor placements by software manufacturers) as well as the establishment of normative data is therefore reinforced so as to allow for improved accuracy and effectiveness when comparing plantar pressure values both nationally and internationally.[15] in addition, gender-race-specific plantar pressure profile data will allow clinicians to evaluate and rate future clients based on the plantar pressure values generated, thereby allowing for better assessment of future clients’ potential injury risk profile. conclusions although the largest pressure values were generally observed under the second and third metatarsal heads of the forefoot when the ten individual foot regions were considered, when the foot was subdivided into the three subregions, the overall largest pressure values were ascribed to the heel region of the foot, closely followed by the forefoot region. �e midfoot region yielded the lowest plantar pressure values. black females, coloured males and coloured females yielded the highest pressure values, particularly when compared under the midfoot region of the foot. black and white males and white females exhibited the lowest plantar pressures, especially under the midfoot region. �e plantar pressure pro�le data generated in this study serve to provide clinicians with an initial frame of reference when evaluating participants with the rs footscan and other footscan systems. values falling outside or within the extreme categories of these norms may prompt the clinician to investigate further, and potentially improve diagnostic accuracy and minimise the possible risk of future injury. future research to further extend the pro�le to larger and more diverse population groups is recommended. furthermore, future research could consider comparing normative plantar pressure pro�le with clinical populations, measuring foot function during gait by determining the centre of pressure excursion index, establishing foot function by measuring the modi�ed arch index, as well as establishing di�erences between plantar pressure exhibited during static weight-bearing in comparison with the dynamic values obtained in the present study. it is also recommended that future research focuses on factors a�ecting plantar pressure values with regard to anthropometric variables such as height, weight, bmi and levels of physical activity. a possible limitation pertaining to the mean age of the present study is that caution should be observed when generalising the normative data to older participants. acknowledgements. acknowledgements include the funding provided by the national research fund (nrf) and the national lottery distribution trust fund (nldtf). references 1. deepashini h, baharudin o, paungmali a, amaramalar n, ohnmar h, leonard j. an insight into the plantar pressure distribution of the foot in clinical practice: narrative review. pol ann med 2014;21:51-56. [http://dx.doi.org/10.1016/j. poamed.2014.03.003] 2. gurney jk, kersting ug, rosenbaum d. dynamic foot function and morphology in elite rugby league athletes of di�erent ethnicity. appl ergon 2009;40(3):554-559. [http://dx.doi.org/10.1016/j.apergo.2008.11.001] 3. hills ap, hennig em, mcdonald m, bar-or o. plantar pressure di�erences between obese and non-obese adults: a biomechanical analysis. int j obes relat metab disord 2001;25(11):1674-1679. [http://dx.doi.org/10.1038/sj.ijo.0801785] 4. nagel a, fernholz f, kibele c, rosenbaum d. long distance running increases plantar pressures beneath the metatarsal heads: a barefoot walking investigation of 200 marathon runners. gait posture 2008;27(1):152-155. [http://dx.doi.org/10.1016/j. gaitpost.2006.12.012] 5. putti ab, arnold gp, abboud rj. di�erences in foot pressures between caucasians and indians. foot ankle surg 2010;16(4):195-198. [http://dx.doi.org/10.1016/j. fas.2009.11.004] 6. røislien j, skare o, gustavsen m, broch nl, rennie l, opheim a. simultaneous estimation of e�ects of gender, age and walking speed on kinetic gait data. gait posture 2009;30(4):441-445. [http://dx.doi.org/10.1016/j.gaitpost.2009.07.002] 7. razeghi m, batt me. foot type classification: a critical review of current methods. gait posture 2002;15(3):282-291. [http://dx.doi.org/10.1016/s09666362(01)00151-5] 8. prentice we. principles of athletic training: a competency-based approach. 10th ed. new york: mcgraw-hill, 2009. 9. van schie chm, boulton ajm. the effect of arch height and body mass on plantar pressure. wounds 2000;12(4):88-95. [http://w w w.medscape.com/ viewarticle/407555] 10. waterman br, owens bd, davey s, zacchilli ma, belmont pj. �e epidemiology of ankle sprains in the united states. j bone joint surg am 2010;92(13):2279-2284. [http://dx.doi.org/10.2106/jbjs.i.01537] 11. burns j, crosbie j, hunt a, ouvrier r. �e e�ect of pes cavus on foot pain and plantar pressure. clin biomech 2005;20(9):877-882. [http://dx.doi.org/10.1016/j. clinbiomech.2005.03.006] 12. rapoo vm. management of recurrent soccer injuries among the premier soccer league (psl) players. ma �esis. limpopo: university of limpopo, 2010. http://hdl. handle.net/10386/271 (accessed 21 march 2012). 13. cavanagh pr, morag e, boulton ajm, young mj, deffner kt, pammer se. the relationship of static foot structure to dynamic foot function. j biomech 1997;30(3):243-250. [http://dx.doi.org/10.1016/s0021-9290(96)00136-4] 14. donatelli ra. normal biomechanics of the foot and ankle. j orthop sports phys �er 1985;7(3):91-95. [http://dx.doi.org/10.2519/jospt.1985.7.3.91] 15. orlin mn, mcpoil tg. plantar pressure assessment. phys �er 2000;80(4):399-409. [http://www.ncbi.nlm.nih.gov/pubmed/10758524] sajsm editorial.indd 62 sajsm vol. 25 no. 3 2013 editorial evaluating the quality of science in exercise and sports medicine with the increasing ease with which information can be obtained from the internet, it is becoming more important to be able to discern ‘good quality’ information from ‘not-so-good’ information. this even applies to scientists who are accustomed to the process of peer review. information on the internet often breaks from convention where scientists aspire to have their research papers published in highimpact journals. the practice of striving to publish in high-impact journals is based on the assumption that high-quality research papers are associated with high impact factor (if) journals. however, this assumption is not always fulfilled. this is because the if of a journal was originally developed by librarians to rank journals; it was not designed as a marker of the quality of the research papers published in the journal. the if is merely a calculation of the ratio between the number of citations of papers and the number of papers published in a defined period.[1] for example, the numerator of the ratio is the number of current-year citations (e.g. citations made in 2012) and the denominator is the total number of published items in that journal in the previous two years (i.e. 2010 and 2011). an example follows: in 2012, all the papers in a particular journal were cited 185 times from papers published in 2010 (n=70 papers) and 2011 (n=75 papers); therefore, the if for 2012 is 185 ÷145 = 1.28. the if has been used to rate the quality of the work of scientists who have to compete for grant funding, or who have to justify reasons for promotion within their academic institutions. however, there is growing concern about the use of the if. firstly, it is misguided to assume that all papers published in journals with high ifs are good studies. some studies might have slipped through the peer review process of the journal, and only in hindsight, may have been exposed as having arrived at the wrong conclusions. secondly, the calculation of the if of the journal also depends on the popularity of the field of research. it stands to reason that journals representing areas of research that attract fewer papers are going to have lower ifs than journals representing areas of research with a global interest, such as hiv or tuberculosis. as a consequence of the unhappiness about this situation in the scientific community, a group of editors and publishers of scholarly journals met at the end of 2012 in san francisco. the group developed a set of recommendations referred to as the san francisco declaration on research assessment.[2] this document acknowledges that the outputs from scientific research are varied and go beyond just research papers in journals. other factors and outputs such as developing databases and software, refinement of technology, intellectual property and training of young scientists should all be considered when the output of a scientist is evaluated. the group recommended that journal-based metrics such as the if should be discontinued, and that research should be assessed on its own merits, rather than on the basis of the journal in which researchers publish. in the field of exercise science and sports medicine, a scientist’s contribution should be evaluated on how service delivery and treatments have been affected as a result of experimentation, whether the original work was conducted in the laboratory or in an applied setting. outputs can also be evaluated by the impact of the research on policy or their contribution to principles of best practice. sometimes the work of an applied scientist is not published in the formal sense, but undergoes sufficient peer review before the principles are utilised in the management of athletes or players. in this setting, the environment is so competitive and demanding that if the recommendations of the scientist do not have any discernible effect, then they will not be utilised by the practitioners or support staff. this is just another check and balance that evaluates the original work done by scientists in the field of exercise science and sports medicine. clearly, this is far more important than the if of the journal in which the paper is published. the publication of this edition of the south african journal of sports medicine coincides with the 15th biennial congress of the south african sports medicine association (sasma), which will be held at the wild coast sun from 24 to 27 october 2013. the organising committee, headed by dr glen hagemann, sasma president, has done a magnificent job in compiling a highquality programme. mike lambert editor-in-chief 1. eston r. the impact factor: a misleading and flawed measure of research quality. j sport sci 2005;23(1):1. [http://dx.doi.org/10.1080/02640410400014208] 2. san francisco declaration on research assessment. http://am.ascb.org/dora/ (accessed 23 september 2013). s afr j sm 2013;25(3):62. doi:10.7196/sajsm.509 2 sajsm vol. 25 no. 1 2013 editorial a walk down memory lane some may have noticed that all the back-dated issues of the south african journal of sports medicine have been digitally converted and loaded onto the journal website (http://www.sajsm.org.za/index. php/sajsm/issue/archive). this was facilitated by the african journal archive project (http://www.ajarchive.org), which is a retrospective digitisation project aimed at building a digital archive of journals published exclusively in africa and about africa. the project is funded by the carnegie corporation and managed by sabinet online. this was done at no cost to the south african sports medicine association (sasma) and was supported by the publishers of our journal, the health and medical publishing group, who then loaded the digitally converted journals onto the website. the journals go back to 1981 and provide a fascinating account of how sports medicine in south africa started and evolved. the first edition of the journal in 1981 had a foreword by dr piet koornhof, the then minister of sport and recreation (see page 5 of the current issue of sajsm). in the foreword he mentioned that medical practitioners should have closer contact with physical education practitioners. prophetic words indeed, given that physical education was dumped from schools soon after that and is still trying hard to make a comeback into the curriculum. in the second edition of the journal in 1981, tim noakes published a paper showing that marathon runners were not immune to coronary heart disease (see page 7 of the current issue). this was contrary to the prevailing belief of the time and was one of the pioneering papers that legitimatised the discipline of sports medicine. this paper received international recognition and established noakes as a creative paradigm buster. in the same edition was a paper that described first aid for the collapsed player on the field. the collapse was attributed to one of 5 causes: ‘heat illness, impact to celiac plexus, head and neck injury, diabetic shock or epilepsy’. the fifth edition of the journal in 1981 is a great issue for making comparisons with topical issues of 2013. for example, there is a paper on concussion. although the paper lacks the detail about concussion management described in the latest zurich concussion consensus that has just been released,[1] it is remarkable in that the advice offered therein for managing concussed players is not too far removed from what would be regarded as best practice today. there is also an article in the fifth edition that describes the comments of an american doctor, john chase, in reference to rugby (see page 22 of the current issue): ‘if a player is hit by a 115 kg forward, and knocked senseless, the trainer will rush onto the field with a little sponge in a bucket of water and whether your teeth are knocked out, your arm is broken, or you have a concussion, you get the magic sponge’. he stated that the days of the ‘magic sponge’ are over, and each rugby team needs its own doctor! once again, prophetic words considering that rugby would only become a professional sport nearly 15 years later! also in this edition was an article calling for greater scientific involvement in managing the psychology and fitness of rugby players. it was argued in the manuscript that while many hours are spent at rugby practice, relatively little time was devoted to achieving suitable levels of fitness. reference was also made to the misconception that players should have a protein intake of steak and eggs before a match. the author also referred to the halftime routine of eating half an orange. he concluded that there needed to be a greater scientific involvement in rugby to manage the wellbeing of players; it is a pity that he did not have a glimpse into the future, 30 years later, where he would have seen the boksmart website, where the ‘a to z’ of player welfare, including their nutrition, is discussed. going back in time can be enlightening for two reasons. firstly, it shows the progress that has been made in the discipline of sports medicine. secondly, it identifies the pioneers who courageously started the discipline and laid the foundation for how sports medicine is currently practised. without their bold beginning, sports medicine would not be where it is today. this first edition of the journal for 2013 has a rugby theme. enjoy the read! mike lambert editor-in-chief 1. mccrory p, meeuwisse wh, aubry m, et al. consensus statement on concussion in sport: the 4th international conference on concussion in sport held in zurich, november 2012. br j sports med 2013;47(5):250-258. [http://dx.doi.org/10.1136/ bjsports-2013-092313] s afr j sm 2013;25(1):2. doi:10.7196/sajsm.463 http://www.sajsm.org.za/index.php/sajsm/issue/archive http://www.sajsm.org.za/index.php/sajsm/issue/archive http://www.ajarchive.org http://dx.doi.org/10.1136/bjsports-2013-092313] http://dx.doi.org/10.1136/bjsports-2013-092313] 23. melanson kj, mcinnis kj, rippe jm, blackburn g, wilson pf. obesity and cardiovascular disease risk: research update. cardiol rev 2001; 9(4): 202-7. 24. nguyen hq, ackermann rt, berke em, et al. impact of a managed-medicare physical activity benefit on health care utilization and costs in older adults with diabetes. diabetes care 2007; 30: 43-8. 25. pedesen bk. body mass index: an independent effect of fitness and physical activity for all cause mortality. scand j med sci sports 2007; 17(3); 196-204. 26. pelletier kr. a review and analysis of the clinical and cost-effectiveness studies of comprehensive health promotion and disease management programs at the worksite: update vi 2000-2004. j occup environ med 2005; 47: 1051-58. 27. pelletier b, boles m, lynch w. change in health risks and work productivity over time. j occup environ med 2004; 46: 746-54. 28. ravussin e, bogardus c. a brief overview of human energy metabolism and its relationship to essential obesity. am j clin nutr 1992; 55: 242s45s. 29. rodgers a, ezzati m, van der hoorn s, lopez ad, ruey-bin l, murray cjl. comparative risk assessment collaborating group. distribution of major health risks: findings from the global burden of disease study. 2004; plos med 1(1): e27. 30. serxner sa, gold db, grossmeier jj, anderson dr. the relationship between health promotion program participation and medical costs: a dose response. j occup environ med 2003; 45: 1196-200. 31. shephard rj. a critical analysis of worksite fitness programmes and their postulated economic benefits. med sci sports exerc 1992; 24; 354-70. 32. song y, manson je, meigs jb, ridker pm, buring je, liu s. comparison of usefulness of body mass index versus metabolic risk factors in predicting 10-year risk of cardiovascular events in women. am j cardiol 2007; 100(11): 1654-8. 33. stein ad, shakour sk, zuidema ra. financial incentives, participation in employer-sponsored health promotion, and changes in employee health and productivity: healthplus health quotient program. j occup environ med 2000; 42: 1148-55. 34. telford rd. low physical activity and obesity: causes of chronic disease or simply predictors? med sci sports exerc 2007; 39(8):1233-40. 35. wang g, pratt m, macera ca, zheng zj, heath g. physical activity, cardiovascular disease, and medical expenditures in us adults. ann behav med 2004; 28(2): 88-94. 36. wareham nj, rennie kl. the assessment of physical activity in individuals and populations: why try to be more precise about how physical activity is assessed? int j obes relat metab disord 1998; suppl (2): s30-8. introduction exercise testing with respiratory gas collection (rgc) and analysis during indirect calorimetry has long been a routine procedure in exercise physiology laboratories, enabling the simultaneous measureoriginal research article abstract objective. despite their widespread use in exercise testing, few data are available on the effect of wearing respiratory gas collection (rgc) systems on exercise test performance. industrial-type mask wear is thought to impair exercise performance through increased respiratory dead space, flow resistance and/or discomfort when compared with rgc facemasks, but whether performance decrements exist for rgc facemask wear versus non-wear is unclear. the objective of this study was to evaluate the difference in incremental exercise test performance with and without a rgc system. incremental exercise test performance with and without a respiratory gas collection system correspondence: james r clark institute for sport research lc de villiers sport centre university of pretoria 0002 pretoria south africa tel: +27 12 420 6033 fax: +27 12 420 6099 e-mail: jimmy.clark@up.ac.za james r clark (bsc (hons), (ba (hons)) institute for sport research, department of biokinetics, sport and leisure sciences, university of pretoria design. twenty moderately active males (age 21.0 ± 1.9 years; vo2peak 55.9 ± 3.0 ml∙kg -1∙min-1) performed two progressive treadmill tests to volitional exhaustion. in random order subjects ran with (mask) or without (no-mask) a rgc facemask and flow sensor connected to a gas analyzer. descriptive data (mean ± sd) were determined for all parameters. the wilcoxon signed rank test for paired differences was used to assess mean differences between mask and no-mask conditions. results. exercise time to exhaustion, peak treadmill speed, peak blood lactate concentration, peak heart rate and rating of perceived exertion (rpe) were not different (p>0.05) between mask and no-mask conditions. conclusions. incremental exercise test performance is not adversely affected by rgc and analysis equipment, at least in short duration progressive treadmill exercise. respiratory gas analysis during exercise testing for diagnostic, performance assessment or training prescription purposes would appear to be unaffected by rgc systems. 44 sajsm vol 20 no. 2 2008 pg40-48.indd 44 8/11/08 8:49:20 am ment of respiratory, cardiovascular and metabolic variables.24 in a clinical setting, risk assessment or diagnosis in patients with known or suspected cardiopulmonary disease is aided by data obtained from respiratory gas analysis during exercise.29 in sport science laboratories, performance assessment of athletes like runners, cyclists and rowers is frequently performed using respiratory gas analysis to monitor training status, evaluate programme efficacy or formulate individual training recommendations.24 however, practical application of measures such as maximal oxygen uptake (vo2max) and mechanical efficiency rely not only on accurate gas analysis during exercise, but also on the premise that rgc does not influence exercise test performance. a range of rgc and analysis systems are available to measure airflow, gas concentrations, and other respiratory variables in the laboratory or field.24 yet a compulsory element of all systems remains the need for a facemask or mouthpiece to physically sample expired air. traditionally this involved a mouthpiece and nose clip, but the oro-nasal facemask has become an increasingly common method of gas collection. a frequently encountered query in practice relates to the effect which the wearing of rgc equipment has on exercise test performance. common criticisms include poor comfort and fit, difficulty breathing and increased anxiety.2,5,10,28 following exercise testing, many individuals complain of an inability to produce true all-out effort performances while wearing the apparatus needed to assess performance from a respiratory or metabolic perspective (clark: unpublished observations). factors implicated in limiting exercise while wearing rgc and analysis systems include the increased dead space and flow resistance they impose.6,14,20 it is also difficult to dismiss the possibility of a psychological effect on exercise performance as a result of wearing such apparatus.5 this raises the concern that exercise testing with rgc systems may not produce truly representative exercise data, potentially affecting the accuracy and value of subsequent performance analysis, training prescription or diagnosis.5,10 the effect of wearing standard rgc equipment, as used in exercise testing, has been the subject of studies before, but these have been limited to comparing one or more gas collection methods rather than comparing mask wear with non-wear.2,3,13,15,28 the aim of this study was therefore to compare incremental exercise test performance, physiological response and perceived exertion of subjects with and without a rgc facemask and flow sensor system. methods subjects twenty male physical education students with no history of respiratory or cardiovascular disease volunteered for the study. table i lists subject physical characteristics. all were healthy, moderately active young men engaging in physical activity involving running, cycling and/or resistance training 3 4 days per week. subjects were briefed on the study purpose and procedures before giving written informed consent. the experimental protocol was approved by the research ethics committee of the university of pretoria. procedures each subject reported to the laboratory on three occasions, each separated by 4 7 days. testing sessions were conducted at the same time of day on each occasion. subjects were instructed to arrive well rested, well hydrated, approximately 3 hours post-prandial, and to avoid caffeinated food and beverages on the day of testing. participants were also required to maintain their normal dietary and physical activity patterns during the study, and to avoid exercise on the day prior to, as well as on the day of exercise testing. the first session involved anthropometrical measurement and familiarisation with the rgc equipment and test procedures. the latter included verbal explanation of the procedures, attachment of the facemask and flow sensor, and a 15-minute treadmill run at 10 km∙h-1. anthropometry body mass (tanita bf-350 electronic scale, tanita co., tokyo, japan), stature (seca 214 stadiometer, seca co., hanover, usa) and skinfold thickness (harpenden caliper, british indicators, west sussex, england) were measured at the first testing session. the durnin and womersley12 method was used to predict body density and percentage body fat (%bf) was estimated using the siri formula described by lohman.22 incremental exercise tests subjects performed a continuous progressive treadmill test (stm-55, quinton instrument co., bothell, wa, usa) to volitional exhaustion on each of the two remaining visits to the laboratory. following 5 minutes of light stretching subjects ran for 5 minutes at 10 km∙h-1 to warm up. thereafter, treadmill speed was increased by 1 km∙h-1 each minute and treadmill grade by 0.5% every 2 minutes. subjects were instructed to provide a maximal effort and verbal encouragement was provided throughout the test. one test involved gas analysis using a rgc facemask and flow sensor (mask condition) connected to an automated gas analyser while the other test was performed without any gas collection or analysis equipment (no-mask). exercise was conducted in an air-conditioned room (~21°c, 50% relative humidity) and both temperature and barometric pressure (~665 mmhg) recorded at the start of each test. the order of the tests was randomised to eliminate any learning effect on test performance over the two trials. laboratory technicians were blinded to the study hypothesis as well as to the subjects’ prior performances during the second tests. during mask testing, a form-fitting silicone rubber hans rudolph 7400 series vmasktm facemask (hans rudolph, inc., shawnee, ks, usa) was attached to the subject’s face using standard mesh headgear. all subjects in this study were appropriately sized for using the small-size facemask with a mask-sizing caliper from the same manufacturer. a 22-mm internal diameter plastic straight swivel port was attached to the mask for a mask plus adaptor dead space volume reported by the manufacturer to be approximately 89 ml. the mask assembly was fitted to the subject and completely sealed, allowing air movement only through the port at the front of the mask. a custommade silicon adaptor was used to attach the port to a silvermantype blendenspiroeptor flow sensor (ganshorn medizi, niederlauer, germany) with a dead space of 55 ml and flow resistance of <1.0 cm h2o∙l -1∙s-1 according to the manufacturer. this resulted in a combined dead space for the mask plus flow sensor system of approximately 150 ml. pulmonary gas exchange and ventilation were analysed with an automated ergo-spirometer (schiller cs-200, ganshorn medizi, niederlauer). during mask tests, oxygen uptake (vo2), carbon dioxide production (vco2), minute ventilation (ve), respiratory rate (fr) and tidal volume (vt) were monitored continuously and recorded every 10 seconds. peak oxygen uptake (vo2peak) and peak ventilation (vepeak) were recorded as the highest vo2 and ve respectively, averaged over 30 seconds during the test. during both mask and no-mask tests, heart rate (hr) was monitored continuously using table i. subject physical characteristics (n=20) characteristic mean sd range age (years) 21.0 1.9 18.0-25.0 body mass (kg) 73.8 3.6 61.6-78.8 stature (cm) 177.8 4.9 170.1-187.3 %bf 14.4 3.1 9.9-22.1 vo2peak 55.9 3.0 51.9-62.0 (ml•kg -1 •min -1 ) %bf = estimated percentage body fat (durnin & womersley, 1974); vo2peak = peak oxygen uptake. sajsm vol 20 no. 2 2008 45 pg40-48.indd 45 8/11/08 8:49:20 am an electrocardiograph. peak hr (hrpeak) was recorded as the highest exercise hr averaged over 10 seconds. exercise time was recorded as the time in seconds from the start of the treadmill until test termination by the subject. peak treadmill speed was defined as the speed of the highest completed 1-minute exercise stage. during all familiarisation and test procedures the subjects had no access to any feedback or information regarding their performance or the elapsed time. blood lactate and perceived exertion capillary blood was obtained from an earlobe using standard procedures described by maw et al.25 blood lactate concentration was measured using a lactate pro (arkray inc. shiga, japan) portable analyser. this was done at 2, 4, and 6 minutes following test termination. peak blood lactate concentration ([la – ]peak) was measured as the highest measured post-exercise blood lactate concentration. immediately following termination of the treadmill test, subjects were asked to rate their overall level of exertion using borg’s rating of perceived exertion (rpe) 15-point category scale.8 data analysis descriptive data (mean ± standard deviation (sd)) were determined for all parameters. the wilcoxon signed rank test for paired differences (bmdp statistical software, inc., los angeles, ca, usa) was used to assess mean differences between mask and no-mask conditions as well as to assess whether there were significant differences between the first and second tests regardless of condition. statistical significance was set at the 0.05 level. results table ii displays the differences in exercise time, peak treadmill speed, hrpeak, [la – ]peak, and rpe for each of the 20 subjects between the two test conditions. there were no significant differences between mask and no-mask conditions for any of these variables. comparisons between the first and second tests also revealed no significant differences (first v. second) in exercise time (677.7±64.0 v. 676.4±54.2 s; p=0.856), peak treadmill speed (15.9±1.0 v. 15.9±1.0 km∙h-1; p=1.000), hrpeak (197±8 v. 197±8 beats∙min -1; p=0.723), [la ]peak (11.5±2.2 v. 10.9±2.0 mmol∙l -1; p=0.131) and rpe (17.5±1.0 v. 17.4±1.2; p=0.782). this suggests that there was no significant learning effect between the first and second incremental test. discussion the major finding of this study was that there were no significant differences between mask and no-mask conditions in incremental exercise test performance. this is different to the finding of burkett and porr,10 who reported significantly shorter (~4%) exercise times with a rgc system in both male and female subjects. they concluded that wearing oxygen uptake measuring equipment clearly reduced treadmill running time and suggested that use of such equipment during exercise testing may produce inaccurate results.10 the results of the present study show no impairment in exercise test performance in mask compared with no-mask conditions, and suggest that concerns over failure to achieve ‘true’ exercise performances as a result of rgc system wear are unfounded. for example, mean exercise time differed by less than 0.1% between mask and no-mask tests in the present study. the effects of wearing full respirator masks,11 gas masks,17 military-type biological respirators,19,20 and self-contained breathing apparatus23 during exercise have been reported. however, these studies all compared exercise using these industrial-type masks with standard rgc systems. results from these studies include reduced submaximal 17 and maximal ve 11,17,19,20, fr 11,17,20 and vo2max , 11,17 but increased submaximal hr17 and vo2 23 while wearing industrialtype masks. in contrast, johnson et al.20 found reduced submaximal table ii. difference in incremental exercise test performance with (mask) and without (no-mask) a respiratory gas collection system time (s) speed (km.h -1 ) hrpeak (beats.min -1 ) [la ]peak (mmol.l -1 ) rpe subject mask no-mask mask no-mask mask no-mask mask no-mask mask no-mask 1 617 614 15.0 15.0 207 210 9.4 9.0 16 17 2 728 726 17.0 17.0 201 198 14.3 12.2 17 17 3 677 672 16.0 16.0 190 188 12.3 13.4 18 18 4 709 672 16.0 16.0 189 186 14.3 11.0 19 19 5 699 719 16.0 16.0 188 188 15.8 15.7 18 19 6 883 842 19.0 19.0 190 185 13.3 9.1 18 18 7 734 746 17.0 17.0 196 192 12.0 11.0 17 17 8 615 654 15.0 15.0 190 194 12.9 13.0 17 18 9 682 676 16.0 16.0 190 188 12.7 11.0 18 17 10 613 596 15.0 14.0 212 209 9.6 8.1 18 19 11 675 666 16.0 16.0 203 206 10.2 12.4 18 18 12 634 616 15.0 15.0 201 198 9.6 9.2 17 18 13 677 681 16.0 16.0 205 207 10.9 13.0 19 18 14 670 673 16.0 16.0 203 200 11.7 8.7 17 16 15 672 689 16.0 16.0 207 205 11.6 11.3 17 17 16 691 720 16.0 16.0 183 184 8.3 11.3 18 18 17 684 696 16.0 16.0 205 202 12.3 12.2 18 17 18 624 645 15.0 15.0 191 203 7.7 7.1 16 16 19 652 631 15.0 15.0 201 198 11.0 10.4 18 14 20 606 606 15.0 15.0 188 189 9.7 9.1 16 15 mean 677.1 677.0 15.9 15.9 197 197 11.5 10.9 17.5 17.3 sd 61.6 57.0 1.0 1.0 8 9 2.1 2.1 0.9 1.3 p value* 0.984 1.000 0.221 0.100 0.593 time = treadmill exercise time to exhaustion; speed = peak treadmill speed; hrpeak = peak heart rate; [la –]peak = peak blood lactate concentration; rpe = rating of perceived exertion. * wilcoxon signed rank test for paired differences (mask v. no-mask). 46 sajsm vol 20 no. 2 2008 pg40-48.indd 46 8/11/08 8:49:21 am sajsm vol 19 no. 4 2007 47 vo2 while wearing a respirator mask and along with higher blood lactate concentrations prompted their suggestion of greater anaerobic metabolism during mask wear. however, ventilatory and lactate thresholds are reportedly not different between respirator and gas collection mask conditions.11,20 interestingly, jetté et al.19 found no difference in vo2max, rer, time to exhaustion, perceived exertion, fr and vt during progressive treadmill exercise with and without a military-type respirator. however, as johnson et al.20 state, in practice it seems workers wearing masks like those described above cannot work as long or as hard as they can without masks. it has been demonstrated that ventilation and the work of breathing during maximal exercise is non-fatiguing and sustainable.1 however, mask-induced respiratory changes remain central in the explanations for impaired exercise performance during mask wear in the studies discussed above. first, an obvious difference between mask wear and non-wear is respiratory dead space. it has been shown, in horses7,14,18 and humans,26 that increased dead space during exercise results in increased vt but not necessarily reduced fr, 3 resulting in variable effects on alveolar ventilation. this altered breathing pattern is thought to be a consequence of increased paco2 secondary to end-tidal re-breathing, mediated via a chemoreceptor reflex26 or as a result of sensory stimulation of the face, mouth and nose.3 secondly, inhalation and exhalation resistance to airflow are augmented by some mask types,11,17 and subject secretions and condensation during exercise may add to the resistance of the mask and flow sensor system. increased flow resistance stimulates a reduced fr and increased vt, 7 potentially increasing respiratory muscle work and the oxygen cost of breathing. together, these factors might be hypothesised to alter breathing patterns, increase respiratory muscle perfusion, impair alveolar ventilation, and hamper co2 elimination and o2 uptake, ultimately contributing to impaired exercise test performance. other less commonly recognised mechanisms have also been proposed to explain physical performance impairment during mask wear. altered breathing patterns may disrupt the coupling of fr to body movement, so-called ‘entrained breathing’ which is characteristic of some activities, preventing ve from reaching a mechanical optimum, and limiting alveolar ventilation.18 also, the additional mass and dimensions of a mask and flow sensor system may alter body movement and exercise economy.23 finally, a psychological limitation to exercise may occur secondary to perceived discomfort, pain or anxiety, leading to the inability to produce a true maximal effort during exercise testing.5 many of these factors may be interrelated. for example, increased respiratory muscle work has been shown to add to the perception of dyspnoea, likely contributing to the overall perception of exertion and discomfort during exercise.16 fundamental differences between the industrial-type masks discussed above and rgc facemasks used in laboratory exercise testing may explain the results of the present study. protective masks typically have a dead space of 150 500 ml and flow resistance of 8.0 10.0 cm h2o∙l -1∙s-1 compared with 70 150 ml dead space and 0.6 1.7 cm h2o∙l -1∙s-1 resistance in a variety of rgc systems.3,11,17,19,20 furthermore, the positioning of large diameter outlets directly opposite and close to the mouth in gas collection masks may minimise the effective dead space and flow resistance markedly in comparison to the construction of industrial-type masks. manufacturers have modified rgc systems over the years, yielding systems with smaller dead space, alternative mask sizes, additional sealers, lighter units, improved comfort and fit, and high-velocity low-resistance valves promoting laminar air flow. it is possible that modern rgc systems are far better tolerated than those used previously. pulmonary ventilation is generally not considered a limiting factor to maximal exercise performance in healthy, untrained, young subjects during dynamic exercise.4 nevertheless, it is possible that at high ventilations turbulent air flow through a modern rgc facemask may rise and subsequently raise flow resistance sufficiently to limit air flow and ve, as is thought to occur in horses. 18 in humans, bradley and younes9 reported that the effective dead space of five commonly used respiratory valves was vt-dependent, approaching the measured dead space only at tidal volumes in excess of 2.0 l. therefore, during high-intensity exercise, rgc mask wear may well alter breathing strategies in a similar manner to the industrial-type masks discussed previously. since, by its nature, no respiratory measures (vt, fr, ve, vo2) are available for the no-mask exercise condition in the present study, and with no measures of blood gases, acid-base status or respiratory muscle work, the effect of wearing rgc systems on these physiological parameters remains unknown. one might speculate though that since exercise test performance was not different between mask and no-mask conditions in the present study, the magnitude, and more importantly, the significance, of rgc system-induced changes in any respiratory parameter seem minimal. jetté et al.19 reported reduced exercise blood lactate concentrations during mask-induced increases in flow resistance despite similar performance time and vo2max measures. they proposed reduced lactate efflux or production due to altered extracellular or intracellular ph as possible reasons.19 the present study found no differences in [la-]peak between mask and no-mask exercise. this supports the notion that a rgc system does not significantly alter lactate production or removal during incremental exercise. the possible psychological effect of wearing any device on the head and face remains a difficult factor to eliminate. in order to monitor expired gas samples some form of gas collection unit close to the face is unavoidable. burkett and porr10 used the traditional method of nasal constriction and a mouthpiece connected to a respiratory valve in their study, a procedure frequently described by subjects as interfering with swallowing, altering breathing patterns and increasing discomfort during exercise (clark: unpublished observations). several studies indicate no difference in exercise time, gas concentration, ve, fr, respiratory exchange ratio (rer) or hr between mouthpiece and facemask exercise in patients with heart failure,5 pulmonary disease28 and in well-trained subjects.13,15 but a rgc facemask, as used in the present study, may be more comfortable than a mouthpiece during exercise,15 particularly maximal exercise, possibly accounting for the difference in results from that of burkett and porr.10 whatever the discomfort or anxiety associated with mask wear, no effect was observed on exercise time, peak treadmill speed or rpe in the present study, suggesting that a psychological effect is either negligible or subject-specific. a potential limitation of this study is that while rgc systems are generally worn for the full duration of clinical or athletic exercise tests, these are mostly progressive in nature and of short duration. dyspnoea, or indeed any mechanism leading to fatigue supposedly due to mask wear, would only need to be tolerated for the final portion of the progressive test,19 potentially delaying exercise termination in the present study. longer exercise times and/or sustained highintensity exercise with gas collection systems may produce different results.17 from this study it would appear that those factors which determine incremental exercise test performance without mask wear also do so during rgc mask wear. in other words, ‘fitter’ subjects perform better in incremental exercise tests whether they wear rgc equipment or not. this implies that any rgc system-induced changes are either too small to have any significant effect on test performance or that the mechanisms leading to test termination are independent of such changes. the results are particularly relevant because indirect calorimetry measures are frequently used to gauge or modify athletic performance or add diagnostic value for patients with known or suspected cardiopulmonary disease. in light of the results of the present study, practitioners should rest assured that rgc does not appear to impair exercise test performance, and probably does not significantly alter physiological response, thereby allowing the accurate assessment of physical performance comparable with mask-free exercise testing. one may speculate that if the work of breathing is indeed altered by rgc systems in some way, conditions in which ventilatory work is already high or cardiac reserve low may sajsm vol 20 no. 2 2008 47 pg40-48.indd 47 8/11/08 8:49:22 am well produce impaired exercise test performance during mask wear. in elite endurance athletes who may approach their mechanical limitation to ventilation during maximal exercise21 or exhibit arterial hypoxaemia,27 increased dead space, work of breathing or altered breathing patterns associated with mask wear may affect exercise performance. patients already limited by respiratory or cardiovascular function may also be less resistant to physiological perturbations brought about by wearing rgc systems, if indeed these occur. further research involving these subject populations is required to more fully understand the effects of rgc systems. conclusions the results of the present study do not support the notion of reduced exercise test performance while wearing a rgc system. these results are different to the findings of several studies investigating the effects of various industrial-type masks on exercise performance, and more specifically, contradictory to commonly held views of coaches, athletes and patients regarding exercise testing with gas collection apparatus. further research incorporating measures of ventilation, blood gases, acid-base status and respiratory muscle work is needed to better describe the physiological effect of wearing rgc systems during exercise. future studies should consider using more sustained, intense exercise protocols and subjects more widely believed to be at risk of developing respiratory limitations during exercise. acknowledgements mr c evans, student in the school of medicine, faculty of health sciences, university of pretoria, is thanked for his energetic administrative assistance, without which this study would not have been possible. mr l parry and mr a mctaggart of the institute for sport research, university of pretoria, are gratefully acknowledged for their assistance with data collection. mrs j h owen, department of statistics, university of pretoria, is thanked for her assistance with statistical analysis. references 1. aaron ea, seow kc, johnson bd, dempsey ja. oxygen cost of exercise hyperpnea: implications for performance. j appl physiol 1992; 72: 1818-25. 2. abadie br, caroll jf. effect of facemask vs. mouthpiece use on physiological responses to exercise. (abstract) res q exerc sport 1993; 64 (suppl): a-23. 3. askanazi j, silverberg pa, j foster r, hyman ai, milic-emil j, kinney jm. effects of a respiratory apparatus on breathing pattern. j appl physiol 1982; 48: 577-80. 4. åstrand p-o, rodahl k, dahl ha, strømme sb. textbook of work physiology: physiological bases of exercise, 4th ed. champaign, il: human kinetics,2003. 5. baran da, rosenwinkel e, spierer dk, et al. validating facemask use for gas exchange analysis in patients with congestive heart failure. j cardiopulm rehabil 2001; 21: 94-100. 6. barlett hl, hodgson jl, kollias j. effect of respiratory valve dead space on pulmonary ventilation at rest and during exercise. med sci sports 1972; 4: 132-7. 7. bayly wm, schulz da, hodgson dr, gollnick pd. ventilatory responses of the horse to exercise: effect of gas collection systems. j appl physiol 1987; 63: 1210-7. 8. borg ga. borg’s perceived exertion and pain scales. champaign, il: human kinetics, 1998. 9. bradley pw, younes m. relation between respiratory valve dead space and tidal volume. j appl physiol 1980; 49: 528-32. 10. burkett ln, porr ds. maximal performance decrement on the treadmill due to wearing respiratory valves. nzjhper 1979; 12: 38-40. 11. dooly cr, johnson at, dotson co, vaccaro p, soong p. peak oxygen consumption and lactate threshold in full mask versus mouth mask conditions during incremental exercise. eur j appl physiol 1996; 73: 311-6. 12. durnin jvga, womersley j. body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. br j nutr 1974; 32: 77-97. 13. evans bw, potteiger ja. breathing apparatus does not affect ventilatory and metabolic measures in trained runners. (abstract) res q exerc sport 1993; 64 (suppl): a-28. 14. evans dl, rose rj. effect of a respiratory gas collection mask on some measurements of cardiovascular and respiratory function in horses exercising on a treadmill. res vet sci 1988; 44: 220-5. 15. farley rs, ray ps, moynihan gp. evaluation of three gas collection devices. int j ind ergon 1998; 22: 431-7. 16. harms ca, wetter tj, st. croix cm, pegelow df, dempsey ja. effects of respiratory muscle work on exercise performance. j appl physiol 2000; 89: 131-8. 17. hermansen l, vokac z, lereim p. respiratory and circulatory response to added air flow resistance during exercise. ergonomics 1972; 15: 15-24. 18. holcombe sj, beard wl, hinchcliff kw. effect of a mask and pneumotachograph on tracheal and nasopharyngeal pressures, respiratory frequency, and ventilation in horses. am j vet res 1996; 57: 250-53. 19. jetté m, thoden j, livingstone s. physiological effects of inspiratory resistance on progressive aerobic work. eur j appl physiol 1990; 60: 65-70. 20. johnson at, dooly cr, dotson co. respirator mask effects on exercise metabolic measures. am ind hyg assoc j 1995; 56: 467-73. 21. johnson bd, saupe kw, dempsey ja. mechanical constraints on exercise hyperpnea in endurance athletes. j appl physiol 1992; 73: 874-86. 22. lohman tg. advances in body composition assessment. champaign, il: human kinetics, 1992. 23. louhevaara v, smolander j, tuomi t, korhonen o, jaakkola j. effects of a scba on breathing pattern, gas exchange, and heart rate during exercise. j occup med 1985; 27: 213-6. 24. macfarlane dj. automated metabolic gas analysis systems: a review. sports med 2001; 31: 841-61. 25. maw g, locke s, cowley d, witt p. blood sampling and handling techniques. in: gore cj, ed. physiological tests for elite athletes. lower mitcham, australia: human kinetics, 2000: 86-97, 433-4. 26. mcparland c, mink j, gallagher cg. respiratory adaptations to dead space loading during maximal incremental exercise. j appl physiol 1991; 70: 55-62. 27. prefaut c, durand f, mucci p, caillaud c. exercise-induced arterial hypoxaemia in athletes: a review. sports med 2000; 30: 47-61. 28. saey d, pepin v, brodeur j, et al. use of facemask and mouthpiece to assess constant-workrate exercise capacity in copd. med sci sports exerc 2006; 38: 223-30. 29. singh vn. the role of gas analysis with exercise testing. prim car 2001; 28: 159-79. 48 sajsm vol 20 no. 2 2008 pg40-48.indd 48 8/11/08 8:49:22 am the conventional approach in the field of exercise science is to report the response to interventions as the mean (average) of the intervention group. while the mean may be a convenient measure, it fails to consider the significant individual variation present in all aspects of human biology, resulting in findings that are at best simplistic and, at worst, misleading. several authors have highlighted the discrepancy between the mean group response and the responses of individual participants by reporting the effects of exercise training programmes that were carefully standardised by frequency and intensity of training. 1-6 these standardised training studies have documented a range of responses in parameters, including maximal oxygen uptake (vo2max), 1,3-6 exercise heart rate, 1,5 resting heart rate, 5 individual anaerobic threshold, 5 blood pressure, 1 hdl-cholesterol, 1 resting respiratory exchange ratio (rer), 2 body composition 2 and performance. 6 a particularly interesting example comes from hautala et al., 3 who measured the change in vo2max after 2 weeks of endurance training. seventy-three sedentary males and females completed the training, and, while the mean response was an improvement of 8±6%, individual values ranged from a 5% reduction in vo2max to a 22% improvement, with an even distribution of responses in between. some may argue that the standard deviation (sd), in this case 6%, is an adequate means of describing the variation in response. in other words, assuming a large sample size and normal sample distribution, 68% of individuals should fall within ±1 sd of the mean or, in this example, between 2% and 14% improvement. there are two potential problems with this approach. the first is that not all readers may be familiar with what constitutes a meaningful difference in a particular measurement and whether the variation should be considered large or small. a 6% difference in performance is most remarkable, whereas a 6% difference in vo2max would be far less so. secondly, as studies sometimes have small sample sizes for logistical reasons, the data may not adequately represent a normal distribution and the assumptions based on sd are less likely to be accurate. an important outcome of training studies is to inform effective exercise prescription. 3 had the authors reported only the mean ±sd, a person adopting a similar training regimen would anticipate an improvement in vo2max of between 2% and 14%. however, there is 32% chance that the individual would fall outside of what is already a considerable range. specifically, 7% of the participants actually recorded a decrease in vo2max, and 29% either recorded a decrease or did not improve beyond day-to-day variation in vo2max. the consequences of poor response to exercise are particularly concerning when an individual engages in training for health reasons, for example to reduce parameters of cardiovascular risk. in such a case, reporting individual responses would alert to the possibility of the exercise not having the desired outcome. another important outcome of training studies is to inform and guide subsequent research. basing the success of a particular intervention on the mean response is an approach vulnerable to error. individuals who respond particularly well, or particularly poorly, will skew the mean and influence the ‘effectiveness’ of the intervention. therefore, avenues of research may be neglected or pursued with misguided enthusiasm when the range in response is not considered. the value of each particular investigation would increase if variation in response was embraced and the ‘poor’ and ‘good’ responders were characterised. however, not all types of research lend themselves to analysis of individual results. large public health interventions or epidemiological studies with sample sizes of several hundred, for example, can clearly not report individual results. both largeand smaller-scale studies would be compatible with a ‘probability’-style approach. for example, if 20 moderately trained runners were to complete 8 weeks of hill training, the authors might report that 2 in 3 had a meaningful improvement in 5 km time trial performance, whereas only 1 in 4 had a meaningful improvement in vo2max. this could be further expanded into those who improved time trial performance by <2%, 3 5%, >5%, etc., using the author’s discretion. this type of method would go some way to encompassing the individual variation, relative effectiveness and potential for nonresponse that are so important when evaluating an intervention. although mean responses, general categories and blanket recommendations may be easier to work with, they are not necessarily realistic. authors are therefore encouraged to report their data as thoroughly as possible and make allowance for individual variation when forming their conclusions. a healthy balance between accessibility, in the form of mean values, and accuracy, in the form of individual values, can only benefit researcher and reader alike. references 1. bouchard c, rankinen t. individual differences in response to regular physical activity. med sci sport exerc 2001;33 suppl:446-451. 2. church t, martin c, thompson a, earnest c, mikus c, blair s. changes in weight, waist circumference and compensatory responses with difference doses of exercise among sedentary, overweight postmenopausal women. plos one 2009;4(2):e4515. 3. hautala a, kiviniemi a, makikallio t, et al. individual differences in the responses to endurance and resistance training. eur j appl physiol 2006;96:535-542. 4. sisson s, katzmarzyk p, earnest c, bouchard c, blair s, church t. volume of exercise and fitness nonresponse. med sci sports exerc 2009;41(3):539545. 5. scharhag-rosenberger f, meyer t, walitzek s, kindermann w. time course of changes in endurance capacity: a 1-yr training study. med sci sports exerc 2009;41(5):1130-1137. 6. vollaard n, constantin-teodosiu d, fredriksson k, et al. systematic analysis of adaptations in aerobic capacity and submaximal energy metabolism provides a unique insight into determinants of human aerobic performance. j appl physiol 2009;106:1479-1486. commentary ‘mean response’ disregards the importance of individual variation correspondence: theresa mann uct/mrc research unit for exercise science and sports medicine newlands tel: +27 21 650 4572 e-mail: tn.mann@uct.ac.za theresa mann (bsc med honours) uct/mrc research unit for exercise science and sports medicine, department of human biology, university of cape town 30 sajsm vol 23 no. 1 2011 case report 1 sajsm vol. 30 no. 1 2018 stress fracture of the thoracic spine in a male rugby player: a case report a shafik,1,2 bsc (hons) sports and exercise sci; k schwabe,1, 2 mbchb, mphil (sport and exercise med); r de villiers,4 mbchb, mmed (rad. d); j t viljoen,1, 2, 3 bsc (hons) physio, mphil (exercise sci); w derman,1, 2 mbchb, bsc (med) (hon), phd, ffims. 1 institute of sport and exercise medicine, division of orthopedics, faculty of medicine and health sciences, stellenbosch university, south africa 2 ioc research centre, cape town, south africa 3 campus health service, stellenbosch university, south africa 4 winelands radiology, institute of orthopaedics and rheumatology, stellenbosch, south africa corresponding author: j t viljoen (jtviljoen@sun.ac.za) professional rugby union players are at high risk of spinal injuries due to scrummaging, tackling and weight training activities.[1] spondylolysis or stress fractures of the vertebral pars interarticularis or other spinal stress fractures are uncommon injuries in rugby which, to the best of these authors’ knowledge, have only previously been described in the lumbar spine and sacrum.[2, 3] here the case of a stress fracture in the thoracic spine of a professional rugby union player is presented. case report history a 21-year-old male professional tighthead prop presented with a three-month history of nocturnal right-sided midthoracic dorsal pain, which started progressively increasing in severity and was further aggravated by playing rugby. the only injury the player could recall was a sternal contusion when he landed on a ball three months prior to the initiation of the back pain. furthermore, the patient’s medical history was unremarkable, with no additional symptoms. examination the initial clinical examination demonstrated mild scoliosis and midline lower thoracic spinal tenderness to palpation. provocative manoeuvres recreating right lower thoracic pain included standing, lateral rib cage compression, forward flexion (fingertips reached mid-tibial level), bilateral rotation and lateral flexion. moreover, resisted flexion of the right hip caused lower thoracic pain. additional examinations revealed nothing further of significance. at this point, a differential diagnosis of soft tissue injury, bony fracture (rib or vertebra), arthritis, infective process and malignancy were considered. investigations: blood tests and imaging studies the patient was initially referred for standard plain radiographs (x-rays) of the thoracic spine. these showed mild dorso-lumbar scoliosis without any further abnormalities. additionally, a comprehensive laboratory blood workup was requested consisting out of a full blood count, an assessment of urea and electrolytes, crp (c-reactive protein) levels, esr (erythrocyte sedimentation rate) as well as serum protein electrophoresis and serum 25-hydroxy vitamin d concentration. all blood results proved to be normal with the exception of slightly elevated phosphate concentration and a low serum 25-hydroxy vitamin d concentration at 22ng/ml. further investigation using magnetic resonance imaging (mri) revealed bone oedema of the t6, t7 and t8 pedicles and superior articular processes with early degenerative disc disease at the cervico-thoracic junction (fig. 1a and 1b). computed tomography (ct) confirmed chronic bone stress reactions on the right t7, t8, t9, t10 pedicles and superior articular processes. chronic bone stress fractures of the right t8 and t9 superior articular processes were also found (fig. 1c). a technetium bone scan plus single-photon emission computed tomography (spect) showed increased uptake in the medial aspect of the t8, t9 and, to a lesser extent, of the t10 pedicles on the right. the uptake extended onto the superior articular processes of the respective vertebrae on the right. based on these findings, the diagnosis of bone stress injury with stress fractures of the right t8 and t9 pedicles was made. treatment the athlete’s most important aspect of his treatment was physical rest from all aggravating exercise, with carefully scheduled reassessment of repeated clinical examinations. once asymptomatic, the athlete participated in a gradual incremental return to individual training and fitness utilising deep water aqua therapy and swimming in warm water before rejoining the squad for further comprehensive sport specific rehabilitation, and eventual return to play. oral vitamin d supplementation in the form of calciferol (50 000 iu weekly) was administered. his blood concentrations had returned to normal when remeasured after two months. this case report discusses a stress fracture of the thoracic spine in a professional south african rugby union player. this is a rare anatomical location for this type of injury in this population and has not previously been described. physicians should be aware that performance of rugby specific movements may lead to rare stress fractures in certain anatomic locations. keywords: overuse injury, sport, bone, back s afr j sports med 2018; 30:1-2. doi: 10.17159/2078-516x/2018/v30i1a4592 mailto:jtviljoen@sun.ac.za http://dx.doi.org/10.17159/2078-516x/2018/v30i1a4592 case report sajsm vol. 30 no. 1 2018 2 discussion a rare case of a stress fracture of the thoracic vertebrae in a professional rugby union player was presented in this case study. spondylolysis is thought to occur due to repeated stress on the vertebra and most commonly occurs in the lumbar spine in rugby players.[2] to date, the only thoracic spinal fracture reported in a rugby player was a traumatic fracture that occurred in a rugby league game.[4] according to these authors, this is the first case study describing a thoracic stress fracture in a rugby union game. this injury should be considered as a differential diagnosis when evaluating rugby players, especially in front row players, who are more susceptible to spinal injuries due to the repeated extreme force experienced during scrum engagement.[5] the pathogenesis of the case is still unclear. consultant opinion from a spinal orthopaedic specialist was discussed with the athlete and it was suggested that the injury might have arisen due to weakness of the athlete’s left shoulder girdle, which resulted in difficulty with binding. the athlete confirmed that his thoracic trunk did indeed flex to the right when scrumming which could explain the unusual right-sided bony stress response. it was suggested that the muscle strength of both shoulders be evaluated and a series of ongoing strengthening exercises be considered if deficits were identified. further suggestions for management included playing in the loosehead position and use of his stronger right arm for firm binding. due to the rarity of this condition, it could be missed and therefore team physicians need to be aware of the possibility of this type of injury in the case of dorsal pain. this is even more crucial in young rugby union players where failure to detect this early on in a diagnosis may result in acute-onchronic injuries throughout a player’s career. finally, it is of interest to note that a series of lumbar spine stress fractures caused the french national professional rugby league to include x-ray and mri of the cervical and lumbar spine as part of systematic screening in academy centres to detect congenital or developmental anomalies that may potentially increase spinal injuries for aspiring professionals.[2] conclusion a thoracic spinal injury, especially bone stress, within sports medicine is a rare but important pathology to consider as a differential diagnosis. a clinician assessing and managing rugby union players should consider this rare injury when confronted with ongoing thoracic pain, particularly in scrumming players. mri and ct form an important modality for diagnosis when a suspicion of injury for these conditions is raised. study funding and conflict of interest: the authors report no funding or conflict of interest. references 1. fuller cw, brooks jh, kemp sp. spinal injuries in professional rugby union: a prospective cohort study. clin j sport med 2007; 17(1):10-16. [doi: 10.1097/jsm.0b013e31802e9c28] 2. castinel bh, adam p, prat c. a stress fracture of the lumbar spine in a professional rugby player. br j sports med 2007; 41(5): 337-338. [doi: 10.1136/bjsm.2006.032789] 3. takahashi y, kobayshi t, miyakoshi n, et al. sacral stress fracture in an amateur rugby player: a case report. j med case rep 2016; 10(1):327. [doi: 10.1186/s1325601611203] 4. geffen s, gibbs n, geffen l. thoracic spinal fracture in a rugby league footballer. clin j sport med 1997; 7(2): 144-146. [pmid: 9113434] 5. trewartha g, preatoni e, england, me, et al. injury and biomechanical perspectives on the rugby scrum: a review of the literature. br j sports med 2015; 49(7): 425-433. [doi: 10.1136/bjsports-2013-092972] fig. 1a. magnetic resonance imaging of thoracic spine (sagittal view), showing bone marrow oedema of the pedicle. fig. 1b. magnetic resonance imaging of t8 vertebrae (axial view) revealing bone marrow oedema in relation to the stress fracture. fig. 1c. computed tomography of thoracic spine (sagittal view) showing significant, unilateral sclerosis of the pedicle and superior articular process with associated fracture lines. c p d q u e s t io n n a ir e instructions 1. read the journal. all the answers will be found there. 2. go to www.cpdjournals.co.za to answer questions. accreditation number: mdb001/008/01/2011 (clinical) sajsm cpd questionnaires must be completed online via www.cpdjournals.co.za. after submission you can check the answers and print your certificate. questions october 2011 1. true (a) or false (b) – click on the correct answer: about 13% of all the papers published in leading medical journals are clinical case studies. 2. true (a) or false (b) – click on the correct answer: the condition of hiv was first reported in a case study. 3. true (a) or false (b) – click on the correct answer: diagnosis in sports and exercise medicine involves a complex art of recognising patterns of illness and injury whose signs and symptoms are consistent from case to case. 4. true (a) or false (b) – click on the correct answer: hamstring muscle injuries are one of the most common injuries sustained by jumping and sprinting athletes. 5. true (a) or false (b) – click on the correct answer: the average time it takes an athlete with a muscle tear to return to sport is about 56 days. 6. true (a) or false (b) – click on the correct answer: one of the most difficult functions of the team physician is to make the decision regarding ongoing participation following injury. 7. true (a) or false (b) – click on the correct answer: disordered eating patterns and menstrual disorders are more frequent in sedentary compared to active females. 8. true (a) or false (b) – click on the correct answer: pathogenic body weight control behaviours (such as restrictive eating, fasting, use of diet pills, laxatives and diuretics) can result in clinical eating disorders. 9. true (a) or false (b) – click on the correct answer: top netball players in south africa have a low risk for disordered eating behaviour, menstrual irregularities and secondary amenorrhoea. 10. true (a) or false (b) – click on the correct answer: arthritis is one of the main causes of disability. 11. true (a) or false (b) – click on the correct answer: rheumatoid arthritis is the least common type of chronic inflammatory arthritis. 12. true (a) or false (b) – click on the correct answer: rheumatoid arthritis only affects the small joints in the hands. 13. true (a) or false (b) – click on the correct answer: the primary goal of exercise therapy for rheumatoid arthritis is to improve joint mobility, muscle strength and aerobic and functional capacity. 14. true (a) or false (b) – click on the correct answer: about 80% of the south african triathletes surveyed in a recent study consumed some form of a cho supplementation. 15. true (a) or false (b) – click on the correct answer: most of the south african triathletes surveyed in a recent study had a very low habitual fat intake. 16. true (a) or false (b) – click on the correct answer: over 90% of the south african triathletes surveyed in a recent study used dietary supplements. 17. true (a) or false (b) – click on the correct answer: kinesthesia, balance and agility exercise (kba) is a neuromuscular training programme designed to improve dynamic joint stability and neuromuscular control. 18. true (a) or false (b) – click on the correct answer: in the united states radiographic knee osteoarthritis is estimated to be present in 37% of people over 60 years of age, with symptomatic knee osteoarthritis affecting 12% of that age group. 19. true (a) or false (b) – click on the correct answer: the overall injury rates for musculoskeletal injuries are lower for athletes with a disability compared with athletes without physical disability. 20. true (a) or false (b) – click on the correct answer: the eating disorder inventory is a self-reported measure designed to assess attitudes, feelings and behaviours typically associated with eating disorders and has been found to be a suitable screening instrument for eating disorders in a non-clinical setting. while chatting to shelly meltzer, head of the dietary practice at the sports science institute of south africa, i learnt about a new concept: the empty-basket or fullbasket approach to managing athletes. shelly used this term in describing the approach she is using when she consults with athletes about nutritional supplements. it is well known from a variety of studies around the world that about 60% of elite athletes ingest supplements 1 and most of these athletes work on the assumption that all supplements are effective and adopt a ‘more-the-merrier’ approach to what supplements they choose to ingest. the full-basket approach is in accordance with this way of thinking. it follows that if you train hard your body needs extra nutrition, which can only be obtained by ingesting supplements. by flooding the body with nutrients, those nutrients that are required are absorbed, and those that are deemed unnecessary, or in excess, are excreted – the net result, according to this approach, is that all the nutritional demands are met. this approach provides comforting insurance, satisfying a ‘just in case …’ way of thinking. the athletes who adopt this approach have mindsets which are wired to ensure that they have an abundance of nutrients, in the event that their bodies need something that is not covered in their habitual nutrition. this is analogous to a caterer preparing for a meal, not knowing the likes and dislikes of the people who will be eating the meal. as a safeguard the caterer provides an excessive variety of food, incurring large amounts of waste and expense. athletes who subscribe to the full-basket approach also do so at excessive monetary cost, while producing nutritious urine which is flushed down the toilet. these athletes also increase their risk of ingesting a contaminated supplement resulting in the failure of a drug test. 2 such athletes are difficult to counsel because this way of thinking is resistant to change. a pragmatic strategy for a dietitian dealing with this type of athlete is to offer advice on what they can remove from their full basket, rather than advising on what they should put in. in other words, their full basket needs to be systematically emptied. in contrast, the empty-basket approach describes a bottom-up approach in which the first step is to examine what an athlete is currently eating. the next step is to make recommendations that accommodate the specific demands of the athlete (i.e. age, gender, training load, level of performance, type of sport, phase of season). once the athlete’s eating habits have been optimised the dietitian carefully considers whether nutritional supplements should be prescribed. recommendations are then made about the dose and brand of supplement and the timing of the ingestion. this is done in accordance with the risk associated with contaminated products. with this approach athletes are monitored and adjustments are made, if necessary, to the supplements. younger, less experienced athletes are more likely to be amenable to this approach. there is no doubt that the empty-basket approach is logical and appealling to anyone who believes in an evidence-based approach to managing athletes. it requires an understanding of the principles of nutrition and the demands of exercise and then matching the two. the reality, however, is that the full-basket approach is more common, particularly among experienced high-performance athletes. the full-basket approach follows the path of least resistance, a quickfix mentality inculcated by peers, and promoted by manufacturers, eager to get a slice of the multibillion dollar international industry. the manufacturers of supplements take advantage of this mentality and flood the market with new products with wonderful claims about their efficacy, cunningly supported by pseudoscience. it is an enormous challenge for health care providers working with athletes, but the only way to change the current prevailing pattern is to consistently promote the empty-basket approach so that this becomes the norm around which recommendations are made. mike lambert editor-in-chief 1. maughan r. contamination of dietary supplements and positive drug tests in sport. j sports sci 2005;23(9):883-889. 2. van der merwe pj, grobbelaar e. unintentional doping through the use of contaminated nutritional supplements. s afr med j 2005;95(7):510-511. empty-basket philosophy editorial 2 sajsm vol 23 no. 1 2011 index title name surname abstract title o1 ms. louise anderson how do transplant athletes experience competitive sport: a volleyball perspective? o2 ms. elizabeth maria atterbury home-based balance training can reduce freezing of gait, but not improve turning ability o3 dr. shelina babul concussions: a conundrum of uncertainty and the need to standardize care the online concussion awareness training tool – www.cattonline.com o4 ms. samantha beckley reliability of rotational knee laxity measurements in healthy participants using the rkt device o5 ms. adele broodryk the psycho-hormonal influence of anaerobic fatigue on semi-professional female soccer players o6 dr. nicholas burger assessing the validity a novel collision sport simulator developed to study tackling and prevent tackle-related injuries o7 dr. carla coetsee the effect of three different exercise training modalities on cognitive and physical function in a healthy older population o8 ms. izaan de jager prevalence, clinical presentation, treatment and severity of exercise associated muscle cramping (eamc) differ between 56km and 21.1km runners: cross-sectional study in 76 654 race entrants o9 mr. steve den hollander the contact skill characteristics of an academy rugby union team o10 mr. f.c. du toit about 1/20 road cyclists report non-traumatic injuries, with 38% of the injuries being severe enough to affect cycling – a crosssectional study amongst 22 560 cyclists o11 dr. lara grobler compression socks and post-exercise recovery: how does it work? o13 mr. charl janse van rensburg statistical methods to explore the relationship between illness and injury in the super rugby tournament o14 prof. dina christina janse van rensburg the injury and illness profile of 23055 participants in a 94.7km cycle race cross-sectional study o15 mrs. audrey jansen van rensburg infections of the respiratory tract account for >50% of all illness during the super rugby union tournament – a prospective study involving 80 088 player days o16 dr. marcel jooste 13.3% runners use prescription medication, mostly to treat hypertension, raised serum lipids, depression and asthma: a crosssectional study in 76 654 distance runners o17 ms. esmè jordaan novel direct and indirect effects of risk factors for exercise associated muscle cramping (eamc) in a cohort of 47784 distance runners over 4 years o18 mr. siyabonga kunene prevalence and modifiable intrinsic risk factors for anterior knee pain among runners in peri-urban communities in ekurhuleni, gauteng province o19 mr. samuel lubega barriers to concussion management in low-income countries. uganda as a case study o20 mr. victor mbayo the effect of progressive resistance exercise intervention on hiv infected individuals taking antiretroviral therapy (art) in zimbabwe o21 mr. solomon mthombeni selected motor fitness test scores for rural emergency medical and rescue services (emrs) personnel in the north west province o22 ms. privilege b.m ndlovu high intensity interval training and detraining effects on cardio-metabolic profiles of young overweight and obese women o23 mr. menzi ngcobo about 1/8 runners report a non-traumatic injury annually, and >50% of these significantly affect training: a cross-sectional study in 29 585 56km runners o24 ms. zingisa nqwena the effect of therapeutic horseback riding on heart rate variability of children with disabilities o25 dr. andre pienaar the biomechanical evolution of a portable muscle testing device (pab®), using air pressure as a biofeedback and strength testing tool a new innovation. o26 dr. stephan praet oral supplementation of specific collagen peptides accelerates improvement in achilles tendon symptoms and function in combination with eccentric exercise. o27 dr. dale rae one night of partial sleep deprivation impairs recovery from a single exercise training session o28 dr. adrian rotunno 13% of 56km, and 4% of 21.1km runners use analgesic/anti-inflammatory medication during events: a cross-sectional study of 76 654 distance runners o29 dr. phoebe runciman high pre-competition injury rate dominates the injury profile at the rio 2016 summer paralympic games: a prospective cohort study of 51,198 athlete days o30 dr. phoebe runciman sport, gender and age increase risk of illness at the rio 2016 summer paralympic games: a prospective cohort study of 51,198 athlete days o31 mr. saint sackey runners self-optimize their kinematics in response to running-induced fatigue after eight weeks of endurance training o32 dr. karen schwabe leisure athletes at risk of medical complications: outcomes of online pre-participation screening among 15 778 endurance runners, using current european guidelines safer vi study o33 prof. martin schwellnus pre-race medical screening and educational intervention reduces medical complications in distance runners: a prospective study in 153 208 race starters (safer vii) o34 prof. martin schwellnus chronic disease, medication use, history of injuries and running experience are associated with exercise associated muscle cramping (eamc): cross-sectional study in 15 778 distance runners o35 dr. sonja swanevelder novel risk factors associated with more severe exercise associated muscle cramping (eamc): a cohort study of 41 698 distance runners o36 dr. tommie swart injuries and illness in athletes with spinal cord injury: lessons from london 2012 summer paralympics o37 prof. elmarie terblanche cerebral haemodynamics and cognitive performance in stroke survivors following exercise o38 ms. gabriella tidbury plantar foot loading patterns of healthy weight and overweight school children from south africa and germany o39 dr. georgia torres sa case studies: the effect of an exercise intervention program on the cardio-metabolic profiles of a diabetic; a metabolic syndrome; a cardiovascular and a depressive patient o40 prof. johan van heerden prevalence and etiology of injuries in trail runners o41 prof. ranel venter differences in foot posture between habitually barefoot and shod children and adolescents o42 mr. jeandré viljoen vitamin d status amongst elite rugby union players – an observational pilot study o43 ms. jeanine watson feasibility of higher intensity goal oriented gait re-training in chronic stroke patients: a pilot study. o44 dr. karen estelle welman somatosensory training improves sensory integration but not haptic feedback in individuals with mild to moderate parkinson’s disease o45 prof. paola wood lifetime prevalence, annual incidence, and incidence of common running injuries differ between 21.1km versus 56km runners: a cross sectional study in 76 654 distance runners index title name surname abstract title ccp1 mrs. emmari carstens an unusual muscle tear in a cricket fast bowler ccp2 dr. ali ganai management of difficult dislocation ccp3 ms. tanya green longstanding bilateral hip pain in a field hockey player ccp4 prof. dina christina janse van rensburg lumbar stress injury or not? – a case study of a cricket player ccp5 prof. dina christina janse van rensburg complicated synovial cyst tibiofibular joint squash – a case study ccp6 dr. gershwin kortje acute, non-traumatic muscle tear in a provincial rugby player, all is not what it seems to be ccp7 dr. mamosilo lichaba not all acute football groin injuries are groin disruptions a multi-system extra pulmonary tb masquerades as an acute sports injury ccp8 dr. riaan van tonder to catch a red herring? : knee pain in a healthy male ultra-marathon runner index title name surname abstract title p1 dr. samahir abuaraki sudancupping test for radiating pain in sport injuries, a new tool for a challenging diagnosis p2 dr. khatija bahdur seasonal variation in vitamin d levels of south african male football referees p3 ms. khatija bahdur the effect of different hydration strategies on recovery on university soccer players. p4 dr. ramona beeton chronic nec pain and headache after cycling p5 dr. ramona beeton lower backache in long distance running sasma 2017 congress: index to abstracts open communication case studies posters p6 mr. theodore calligeris the incidence of injuries and exposure time of professional football club players in the premier soccer league during football season p7 dr. rob donkin case study of a javelin thrower with medial elbow pain with median nerve involvement p8 dr. olessia gorkovenko the insightful relationship between spiritual intelligence and workplace in 21’st century p9 dr. cc grant novel method to decrease core temperature in hyperthermic athletes p10 dr. henriëtte hammill the adverse impact of schoolbag carriage: a systematic literature review (2007-2016) p11 prof. dina christina janse van rensburg evidence of benefits of exercise and its mechanisms in inflammatory arthritis p12 dr. leon lategan selected fitness values of male and female junior provincial swimmers p13 ms. cassandra lister effects of an integrated movement programme on motor proficiency, visual-motor integration and scholastic achievement in grade one learners of quintile five schools in port elizabeth p14 dr. vincent masocha two-year changes in body composition, physical activity, and selected metabolic risk factors among adolescents living in the north west province of south africa: the pahl study p15 mr musa mathunjwa physical characteristics and anthropometric profiles of kzn male taekwondo team p16 mr musa mathunjwa effects of a six-week high interval taekwondo and resistance training on anthropometrical and physical parameters in kzn taekwondo athletes p17 ms. sinikiwe mhlanga overweight, obesity, chronic disease risk and physical activity levels of urban and rural women in zimbabwe. p18 dr. waeil mohammed acute quadreceps muscle radiating pain during football game, wrongly diagnosed as acute muscle strain. sudan cupping test sorted the problem. p19 dr. bhekiwe mtshali physical activity levels and sedentary behaviour of high school learners in soshanguve, gauteng province p20 dr. habib noorbhai a novel coaching cricket bat: can it be used to enhance the backlift and performance of junior cricket batsmen? p21 dr. habib noorbhai the lateral backlift in cricket: does it affect other components of the batting technique? p22 mr przemysław pękala the biomechanics of the achilles tendon: a digital image correlation study using a high-speed camera p23 mr. przemysław pękala "what gives the achilles tendon a spin?" anatomy of the achilles tendon and its subtendons p24 mr. przemysław pękala age-related changes in the anatomy of the achilles tendon insertion p25 dr. lervasen pillay high ankle sprains. case series of conservative treatment with prp p26 dr. lervasen pillay the use of regenerative medicine techniques in the treatment of hip labral injuries: a case study p27 dr. karabo raphokwane exercise therapy: effectiveness on activities of daily living on hiv lung disease patients p28 dr. takshita sookan resistance training reduces t helper cytokine levels but not cardiometabolic risk factors in hiv-infected individuals receiving art. p29 ms. andrea steyn oat beta-glucan: an alternate cholesterol management nutrient for athletes p30 mr. eberhard munetsi tapera release parameters of the best jump shots in elite male zimbabwe basketball players. p31 mr. eberhard tapera selected release parameters of the clean shots executed by male league zimbabwe basketball players. p32 mrs. anneke van biljon effects of exercise intensity on heart rate variability in children p33 dr. candace vermaak bridging the gap between inpatient rehabilitation and outpatient health and wellness in spinal cord injured patients p34 dr. yolandi willemse a comparison between the cardiorespiratory responses of a speed versus an incline motorized treadmill protocol. p35 prof. paola wood measuring functional balance in the elderly: comparison of three balance tests index title name surname abstract title pp1 ms. sarah arnold the effect of unilateral transtibial amputation on locomotion and postural stability: a systematic review pp2 dr. christo bisschoff the use of heart rate variability and recovery to determine the fitness levels of a cohort of university-level rugby players pp3 dr. jill borresen big data analytics in sport, exercise and physical activity: a systematic review pp4 dr. james burger if the shoe fits… should you wear it? a calcaneal stress fracture in a female recreational runner pp5 mr. simon de waal endocrine response to small-sided games and match play in elite u19 south african soccer players pp6 mr. adiele dube effects of regular aerobic exercises on lung function in zimbabwean elderly men pp7 dr. gary gabriels schedule 5 drug fluoxetine in dietary/nutritional supplements – storm in a teacup or requirement for improved regulation and accelerated enforcement? pp8 dr. david goble an integrated investigation into the determinants of putting success: a biomechanical, cognitive and anthropometric approach pp9 ms. shaundre jacobs the effectiveness of the south african sport academy system towards high performance sport development pp10 mr. bhekuzulu khumalo participation likelihood assessment tool for wheelchair basketball pp11 dr. jannelene killops 20.7% cyclists entering a 109km race report risk factors for cvd, and 3.7% report existing cvd: pre-participation screening among 22 650 cyclists safer cycling pp12 dr. zarko krkeljas relationship of aslr and functional movement deficiencies in physically active individuals with and without low back pain pp13 mr. siyabonga kunene the impact of barefoot versus shod running on lower limb gait cycle pattern among recreational club runners in durban, kwazulunatal pp14 mr. daga makaza lifestyle risk profiles of primary school teachers: a school-based professional development intervention pp15 mr. loyiso maqina health related risk behaviours amongst university residence student pp16 mr musa mathunjwa the effect of six weeks taekwondo and strength training program on body composition and physiological parameters in university taekwondo athletes pp17 prof. andries monyeki association between sport participation, body composition, physical fitness and social correlates among adolescents: the pahl study pp18 prof. sarah moss exercise as conservative treatment for shoulder impingement syndrome: a systematic review pp19 dr. rowena naidoo the carry-over effect of an aquatic-based intervention in children with cerebral palsy pp20 prof. rafiu olaoluwa okuneye growth pattern profile and motor performance of basic school children in sub-urban population in nigeria pp21 mr. przemysław pękala pathways of fluid leakage from the retrocalcaneal bursa to the achilles tendon a radiologic study with implications for brusal steroid injections pp22 mrs. jana storm a comparison between the cardiorespiratory responses of a non-motorized and motorized treadmill protocol. pp23 ms. lynn van rooy comprehensive cardiac rehabilitation and quality of life in coronary artery bypass graft patients pp24 dr. santa-marie venter the prevalence, risk factors predicting injury and severity of injuries sustained during competition in professional mixed martial arts in africa oral / "flash" poster presentation open communication o1: how do transplant athletes experience competitive sport: a volleyball perspective? louise anderson1, sheila leddington-wright1, dr annette roebuck1, dr mike price1 1coventry university presenting author e-mail address: anders87@uni.coventry.ac.uk introduction: following organ transplantation, near-normal levels of physical functioning and quality of life are possible with greater levels being achievable for those partaking in regular physical activity (painter et al 1997). current research, however, considers the physiological aspects of organ transplantation per se with little published research concerning transplant athletes’ experiences within competitive sport. aim: to explore transplant athlete’s experiences of competitive sport methods: an ethnographic study was undertaken with 11 athletes from both great britain (n=9) and united states (n=2) transplant volleyball teams. initial analysis of publicly available documents, in the form of; newspaper cuttings, magazine articles and case studies from the transplant sport website, informed the direction of the interview matrix. subsequently, face to face semi-structured interviews lasting approximately one hour were held with the athletes during training camps. analysis of artefacts and interviews was undertaken, coding all the data through the use of computer software (nvivo). themes were developed through identifying, coding, classifying and labelling patterns in the data. results: the following emerging themes were observed: shift in relationship with sport: athletes pre-transplant sporting activities may not match those of transplant games events, therefore, to compete at the national and international transplant games athletes must adapt and develop alternative sports. factors contributing to decisions regarding sport played: the positioning of a kidney transplant, due to their vulnerable location, may be a factor in determining whether kidney transplantees are able to participate in contact sports, however, the mechanisms by which such decisions of medical staff are made, and the impact that they have are unknown. analysis of published media focused mainly on the transplantee’s life journey with information on sport being factual reporting of sporting events. conclusion: pre-transplant sporting activities played by transplantees are not necessarily included in the transplant games. for kidney transplantees post-transplant sporting activities appear to be limited and restricted possibly due to the position of the donated organ. future research: to understand factors preventing transplantees participating in sport, including fundamental questions and advice given by medical staff concerning participation within sport for a range of transplantees. o2: home-based balance training can reduce freezing of gait, but not improve turning ability elizabeth maria atterbury1, karen estelle welman1 1stellenbosch university presenting author e-mail address: ematterbury@gmail.com introduction: freezing of gait is a major mobility problem for individuals with parkinson’s disease (pd). not only does it impact the effectiveness of movement but can also be accompanied by postural instability during walking and turning. often this can result in subsequent falls which reduces independence and quality of life. the aim of this study was to assess the efficacy of a home-based compared to therapist-supervised balance training programme on freezing of gait and turning effectiveness. methods: based on a sample of convenience, 40 participants with mild to moderate parkinson’s disease (hoehn & yahr stages i – iii) were allocated to a therapist-supervised (n = 24, age 65.4 ± 8.3 years) or home-based group (n=16, age 64.9 ± 7.1 years). within each group 50% of individuals reported experiencing freezing. both groups followed eight weeks of balance training; the therapist-supervised group attended classes with a qualified biokineticists and the home-based group followed a series of guided dvds at home. primary outcome variables were measure preand post-intervention and included turning ability assessed with the modified instrumented timed-up-and-go, mobility parameters assessed with a functional gait analysis, and freezing of gait assessed by self-reported questionnaire. results: the main findings for this study are that both groups experienced a decrease in reported freezing of gait after intervention. freezers scored worse in balance and gait measurement at pre-test than non-freezers (p 0.05), but improved significantly after the intervention. only the freezers in the therapist-supervised group improved their turning duration (p = 0.04), and turning velocity (p = 0.02), while freezers and nonfreezers of the therapist-supervised group improved turn-to-sit duration at post-tests (p 0.001). conclusions: this study has verified that individuals who experience freezing are likely to have less functional mobility, including gait and turning actions. an eight-week balance intervention with a therapist can improve the efficacy of a turn when the exercises are presented by an exercise scientist. home-based training does not seem to be nearly as effective as therapist-supervised training in improving turning ability, but it is however effective in reducing self-reported freezing of gait severity. o3: concussions: a conundrum of uncertainty and the need to standardize care the online concussion awareness training tool – www.cattonline.com shelina babul1, dr. ian pike1, ms. kate turcotte1 1university of british columbia, vancouver, canada; bc children's hospital, vancouver, canada presenting author e-mail address: sbabul@bcchr.ca context: the concussion awareness training tool (catt, www.cattonline.com) is an online resource with three comprehensive toolkits providing training in the recognition and treatment of concussion. based upon international consensus on concussion in sport and other evidence-based resources, each toolkit includes a self-paced learning module as well as tailored resources. catt for medical professionals aims to standardize practice in a clinical setting with a focus on the paediatric patient. resources include diagnostic tools, clinical resources, patient handouts, journal articles, websites, videos and case studies. physicians demonstrated significant positive change in concussion practices, and significant change in knowledge by those treating >10 concussions per year. nurses had significant positive change in practices and attitudes. catt for parents, players and coaches speaks to concussion identification and management, with resources including the smartphone accessible concussion response tool and questions to ask your doctor. parents demonstrated significant positive change in concussion knowledge. catt for school professionals includes return-to-learn protocol and resources to support teachers, administrators, counsellors and others in the school setting. teachers and school administrators demonstrated significant positive change in concussion knowledge. objective: to promote the implementation of an evidence informed concussion awareness training tool. mailto:anders87@uni.coventry.ac.uk mailto:ematterbury@gmail.com mailto:sbabul@bcchr.ca http://www.cattonline.com/ key messages: to date, over 100 relationships have been developed with organizations and key stakeholders in british columbia and beyond, more than 10,000 print resources distributed, >25,000 coaches and parents and >2,000 school professionals have completed catt, and >15 sporting organizations and schools have mandated catt. continuing implementation will include enhancing catt mp by adding modules to include dealing with persistent concussion symptoms (e.g., persistent headaches), supporting good sleep hygiene, and speaking to the need to support mental health (social/emotional wellbeing). other additions may include language translation, a workplace concussion toolkit (employee/employer awareness), and developing a toolkit aimed at elite, university and professional athletes. discussion and conclusions: concussion is an under-recognized, -diagnosed and -treated medical condition, requiring physical and mental rest. catt addresses this gap by increasing knowledge and awareness among appropriate audiences. good concussion management can reduce health problems and the risk of long-term brain damage, potentially lowering total health care costs. o4: reliability of rotational knee laxity measurements in healthy participants using the rkt device samantha beckley1, dr thomas branch2, dr shaun stinton3, assoc prof alison september1 1division of exercise science and sports medicine, university of cape town, 2university orthodepics, 3arthrometrix, llc presenting author e-mail address: sambeckley@gmail.com a number of clinical tests exist to assess knee laxity, which is defined as the displacement or rotation of the tibia in relation to the femur. these assessments, which are the predominant tools of diagnosis, are subjective and rely on the experience of the clinician. the dial test is typically used to assess rotational laxity. the robotic knee testing (rkt) device has been developed in order to quantitatively and objectively measure rotational knee laxity. the purpose of this study was to determine the intra-tester reliability of the rkt device. twenty healthy participants (10 males and 10 females) with no lower limb injuries were recruited and tested using the rkt device daily over five consecutive days to determine the icc value. measurements were carried out by external and internal rotation of the tibia of both legs using a servometer, until a maximal torque of -5.65 n m and 5.65 n m respectively was reached. these measurements were repeated and carried out for three cycles. data from the third cycle were used to generate a load deformation curve. after completion of the study, a total of four participants’ data were excluded due to initial setup errors. the rstudio statistical environment was used to calculate icc for both legs combined and each individual leg. preliminary results demonstrated icc values between 0.7 and 0.85. the externally rotated measurements of the left lower limb had lowest icc value of approximately 0.6. the rkt device showed good to excellent reliability in measurements of external and internal rotational laxity. the lower icc values during the external rotation of the left lower limb in comparison to the right lower limb suggests these values could be improved. we hypothesise these reliability scores could be improved by a more stringent setup process of the equipment and participant. therefore, we recommend (i) further training in the use of the rkt device, (ii) implementation of software assisting in correct initial setup and a (iii) further testing of a larger sample size. o5: the psycho-hormonal influence of anaerobic fatigue on semi-professional female soccer players adele broodryk1, cindy pienaar1, david edwards2, martinique sparks1 1physical activity, sport and recreation research focus area internal box 494 faculty of health sciences north-west university potchefstroom, 2psychology department university of zululand private bag x1001 kwadlangezwa presenting author e-mail address: adele.broodryk@nwu.ac.za globally it is assumed that high-intensity activities are the general cause of fatigue experienced during a soccer match. however, little is known about the hormonal and psychological effects of fatigue due to these activities on semi-professional female soccer players. forty-seven female players (22.0 ± 2.7 y) from a tertiary education institution volunteered for the study. their cortisol values (saliva sample), anxiety [spielberger state-trait anxiety inventory questionnaire (stai)] and mood scores [incredible short profile of mood states questionnaire (isp)] were taken an hour and immediately prior to, and 15 minutes after an anaerobic fatiguing test (aft). during the aft, subjects completed a 5-m multiple shuttle run test and their hrmax, blood lactate (bla-) and rate of perceived exertion (rpe) taken afterwards. anxiety scores were divided into three categories and mood scores into the total mood disturbances (tmd) and six subscales. the results indicated an increase in cortisol, psychological fatigue and tmd from baseline and/or preto post-aft (p 0.05). vigour and confusion decreased from baseline and/or preto post-aft (p 0.05). a relationship was seen between state-anxiety and tmd (r ≥ 0.63, p 0.05) at all three time points, as well as between state-anxiety and hrmax (r = 0.37, p = 0.03). cortisol and rpe (r = –0.34, p = 0.03) demonstrated a correlation post-aft. this is the first study to evaluate the effects of anaerobic fatigue on the hormonal and psychological states of female soccer players. the results suggest that an aft can be perceived as a physiological and psychological stressor by female players, hence has the ability to influence performance. altering a player’s awareness and anaerobic fitness level might therefore influence both the hormonal and psychological consequences of the stressor, subsequently reducing the experience of fatigue and thereby enhancing performance. o6: assessing the validity a novel collision sport simulator developed to study tackling and prevent tackle-related injuries nicholas burger1, mike lambert1 2, harry hall1, sharief hendricks1 3 1division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, cape town, south africa, 2department of public & occupational health and the emgo institute for health and care research, vu university medical center, amsterdam, the netherlands, 3institute for sport, physical activity and leisure, centre for sport performance, school of sport, fairfax hall, headingley campus, leeds beckett university, leeds, ls6 3qs, united kingdom, , presenting author e-mail address: nicholas.burger@uct.ac.za introduction/background: it is necessary to study the rugby tackle in detail as it occurs most frequently in comparison to other contact phases and has the highest propensity to cause injuries, including severe and sometimes catastrophic head and neck injuries. as a result of these risks, the tackle has recently been subject to significant scrutiny and an official call was made to ban contact rugby at schoolboy level. with only a limited pool of data available detailing the discrete biomechanical properties of the tackle, a novel collision sport simulator was developed to study and train the tackle in a controlled laboratory environment. mailto:sambeckley@gmail.com mailto:adele.broodryk@nwu.ac.za mailto:nicholas.burger@uct.ac.za methods: the collision sport simulator consists of five primary components; (1) an a-frame gantry, (2) pneumatic system, (3) twin trolley system, (4) shock absorbing units, and (5) a custom-built tackle dummy. testing comprised two phases involving two unique conditions; (1) tackling using the collision sport simulator i.e. tackling the dummy, and (2) tackling during a standardised ‘live’ one-on-one tackle drill i.e. tackling a human ball-carrier. tackling performance and proficiency were compared between conditions using a list of technical criteria. mean criteria scores, standard deviations, and cohen’s d effect sizes were calculated for the comparative analysis. results: mean overall score for dynamic simulator tackles was 7.78 (95%ci 7.58-7.99) (out of 9) or 87% (sd±8.94), and mean overall score for dynamic ‘live’ tackles was 7.85 (95%ci 7.57-8.13) (out of 9) or 87% (sd±9.60) (effect size=0.08; trivial; p>0.05). mean overall score for static simulator tackles was 7.45 (95%ci 7.20-7.69) (out of 9) or 83% (sd±10.71), and mean overall score for static ‘live’ tackles was 8.05 (95%ci 7.838.27) (out of 9) or 89% (sd±7.53) (effect size=0.72; moderate; p0.001). conclusion: the simulator replicates dynamic tackle performance and technique comparable to real-life tackle drills and may be used for research analysing various aspects of the tackle in rugby and other contact sports. these aspects include, but are not limited to, head and neck kinematics and shoulder impact forces. data from this research may help guide clinicians, conditioning coaches, and various other key stakeholders working in rugby to formulate novel injury prevention strategies. o7: the effect of three different exercise training modalities on cognitive and physical function in a healthy older population carla coetsee1, professor elmarie terblanche1 1stellenbosch university presenting author e-mail address: carlac@sun.ac.za background: older adults are encouraged to participate in regular physical activity to counter the age-related declines in physical and cognitive health. literature on the effect of different exercise training modalities (aerobic vs resistance) on these health-related outcomes is not only sparse, but results are inconsistent. in general, it is believed that exercise has a positive effect on executive cognitive function, possibly because of the physiological adaptations through increases in fitness. indications are that high-intensity interval training is a potent stimulus to improve cardiovascular fitness, even in older adults; however, its effect on cognitive function has not been studied before. the purpose of the study was to compare the effects of resistance training, high-intensity aerobic interval training and moderate continuous aerobic training on the cognitive and physical functioning of healthy older adults. methods: sixty-seven inactive individuals (55 to 75 years) were randomly assigned to a resistance training (rt) group (n=22), high-intensity aerobic interval training (hiit) group (n=13), moderate continuous aerobic training (mct) group (n=13) and a control (con) group (n=19) for a period of 16 weeks. cognitive function was assessed with a stroop task and physical function with the timed-up-and-go (tug) and submaximal bruce treadmill tests. results: no significant group x time interaction was found for stroop reaction time (p > 0.05). the hiit group showed the greatest practical significant improvement in reaction time on the information processing task, i.e. stroop neutral (es = 1.11). mct group participants had very large practical significant improvements in reaction time on the executive cognitive tasks, i.e. stroop incongruent and interference (es = 1.28 and 1.31, respectively). the hiit group showed the largest practically significant increase in measures of physical function, i.e. walking endurance (es = 0.91) and functional mobility (es = 0.36). conclusion: mct and rt proved to be superior to hiit for the enhancement of older individuals’ executive cognitive function; whereas hiit were most beneficial for improvement in information processing speed. hiit also induced the largest gains in physical function. o8: prevalence, clinical presentation, treatment and severity of exercise associated muscle cramping (eamc) differ between 56km and 21.1km runners: cross-sectional study in 76 654 race entrants izaan de jager1, martin schwellnus2 3, sonja swanevelder4, esme jordaan4 5 1sport exercise medicine and lifestyle institute (semli) and department of physiotherapy, faculty of heath sciences, university of pretoria, south africa, 2sport exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa; 3international olympic committee (ioc) research centre, south africa; emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south afric, 4biostatistics unit, south african medical research council, 5statistics and population studies department, university of the western cape presenting author e-mail address: zdejager@hotmail.com background: eamc is a common complication during distance running. differences in the epidemiology and clinical presentation of eamc in 21.1km vs. 56km runners have not been investigated. the purpose of this study was to determine if the lifetime prevalence (%), clinical presentation, severity and self–reported treatment for eamc differs between 21.1km and 56km runners. methods: data from 76 654 consenting race entrants over 4 years (21.1km= 47 069) (56km= 29 585) who completed a pre-race medical screening tool, that included data on history, clinical presentation and treatment of eamc, were analysed. 10 614 runners indicated a history of eamc, and were included in this study. the lifetime prevalence, clinical presentation, severity and self–reported treatment for eamc was compared (crude %; 95%ci) between the 56km and 21.1km runners. results: the lifetime prevalence (%) of eamc in all runners was 13.9% (13.6-14.1), and this was significantly higher in the 56km (21.1%; 20.621.5) vs. the 21.1km (9.3%; 9.1-9.6) runners (p0.05). 62.2% (61.3-63.2) of runners with eamc reported eamc in the past 12 months. although most runners experienced cramping either in the fourth quarter (48.1%; 47.2-49.1) or after the race (22.1%; 21.3-22.9), 21.1km runners reported eamc more frequently in the first quarter (21.1km=4.9%, 4.2-5.5: 56km=1.3%; 1.1-1.6), second quarter (21.1km=3.6%; 3.1-4.2: 56km=2.4%; 2.02.7), and after the race (21.1km=29,0%; 27.7-30.4: 56km=17.3%; 16.3-18.2) compared to the 56km runners. the most frequent muscle groups affected by eamc was calves (53.8 %), and this was significantly higher in the 21.1km runners (62.1%, 60.7-63.6) compared to 56km runners (48.0%, 46.7-49.2). serious forms of eamc were significantly more frequent in the 56km group compared to 21.1km runners, specifically for whole body cramping (56km=5.5; 4.9-6.1: 21.1km=2.8%; 2.3-3.3) and eamc with dark urine (56km=3.8%; 3.3-4.3: 21.1km=2.0%; 1.6-2.4). in both groups, the most successful self-reported treatment to relieve an acute cramp was stretching, followed by rest, and massage. conclusion: 56km runners experience eamc more frequently and report more severe forms of eamc, compared with 21.1km runners. 21.1km runners experience eamc earlier in races. these data indicate that the risk factors and causes of eamc may differ between these two groups of runners. mailto:carlac@sun.ac.za mailto:zdejager@hotmail.com o9: the contact skill characteristics of an academy rugby union team steve den hollander1, dr sharief hendricks1 1uct presenting author e-mail address: steve_dh1989@hotmail.com rugby union is a field based collision sport, requiring strength, speed, deception and skill (williams & bunce 2012). typically, coaches use standardised physical assessment protocols to evaluate the physical characteristics of their players. the results of the assessments are subsequently used as a tool to screen whether a player can meet the physical demands of the sport. however, to authors’ knowledge, no standardised skill assessment protocols exist to evaluate whether players meet the skills demands of rugby union. for this purpose a skill assessment protocol for rugby union was developed. the protocol incorporates a number of drills and tasks which assess rugby specific technical, tactical and perceptual skills. the technical skill assessments involve the participants taking part in contact and noncontact drills which are filmed. this allows the researcher to retrospectively analyse the participant’s technique using standardized technical criteria. these criteria were developed based on the guidelines of a national rugby union (posthumus & viljoen 2008). the criteria have also been used in video analysis research, and high skill proficiency scores have been associated with reduced risks of injury (hendricks et al. 2015; burger et al. 2016) and improved performance (hendricks et al. 2014; tierney et al. 2017) in contact. this study used the skill assessment protocol to describe the skill characteristics of an academy rugby union team. thirty rugby players from a local academy took part in the field based contact drill. the drill, a 3 on 2 contact drill, assessed the players’ tackle, ball-carrier, and ruck clearing technique. 74% of ball-carriers had a ‘straight back’ going into contact and 45% were ‘explosive’ in contact. 95% of tacklers had their ‘heads up’ pre-contact, 63% of tacklers made contact with the ball-carrier’s centre of gravity. only 17% performed a ‘leg drive’ post contact. 98% of players went from an ‘upright to low’ body position prior to going into a ruck, however only 38% ‘dipped and stepped into contact’. the execution of the above mentioned techniques have been associated with reduced injury risks and improved performance. this information can therefore be used by coaches to improve performance and decrease injury risk. o10: about 1/20 road cyclists report non-traumatic injuries, with 38% of the injuries being severe enough to affect cycling – a crosssectional study amongst 22 560 cyclists f.c. du toit1, paola wood1, martin schwellnus2, sonja swanevelder3 1sport, exercise medicine and lifestyle institute (semli) and division of biokinetics and sports science, department of physiology, faculty of health sciences, university of pretoria, south africa, 2sport, exercise medicine and lifestyle institute (semli) & section sports medicine, faculty of health sciences, university of pretoria, south africa; international olympic committee (ioc) research centre, south africa, 3biostatistics unit, south african medical research council presenting author e-mail address: fcdutoit85@gmail.com introduction: road cycling increases in popularity, but there is an increased risk of injury amongst both amateur and professional cyclists. there are sparse data on the epidemiology and risk markers for non-traumatic (chronic, “overuse”) injuries (nti) in recreational cyclists participating in mass community based cycling events. the aim of this study is to determine the lifetime prevalence of nti, anatomical areas affected by nti, and severity of nti in a large cohort of road cyclist participating in the cape town cycle tour. methods: this is a cross-sectional study on recreational cyclists that participated in the 2016 cape town cycle tour (109km). 37 425 race entrants were required to complete an online pre-race medical screening questionnaire and 22 560 consenting cyclists (60.3%) were included in this study. we report the crude (un-adjusted) lifetime prevalence (%; 95%ci) and common anatomical areas of nti, and specific cycling nti’s (% cyclists with nti; 95%ci). results: the lifetime prevalence of nti is 4.4% (4.1-4.7) and 34.4% of cyclists with nti reported becoming aware of the injury between 1–6 months ago. ntis were reported equally on the left (32.1%; 28.2-36.1) and right (32.0%; 28.0-35.9) sides of the body. the most common anatomical areas for ntis were the knee (27.8%; 24.0-31.6), followed by the lower back (11.10%; 8.4-13.8), and the shoulder (9.8%; 7.3-12.3). ntis occurred most commonly in muscle (19.0%; 15.7-22.3), and tendon (17.5%; 14.3-20.7) tissue. the most common specific ntis in cyclists were patellofemoral pain (14.7%; 11.7-17.7), lower back pain (10.3%: 7.8-12.9) and iliotibial band friction syndrome (9.8%; 7.3-12.3). in 8.8% (6.4-11.3) and 29.3% (25.5-33.2) of cyclists with nti, injuries were severe enough to prevent cycling, or interfere with training, respectively. conclusion: about 1 in 20 recreational cyclists report ever suffering from a non-traumatic injury. these injuries affect mostly the knee, lower back and shoulder (47% of injuries) and >38% injuries are severe enough to affect training and competition. o11: compression socks and post-exercise recovery: how does it work? lara grobler1, prof elmarie terblanche1 1stellenbosch university presenting author e-mail address: lgrobler@sun.ac.za two theories exist to explain the physiological mechanism whereby compression socks aid post-exercise recovery. the first is that the socks increase venous return from the periphery, thereby facilitating greater lactate removal in the muscle. the second theory suggests the retention of lactate within the muscle due to the external mechanical pressure provided by the socks, therefore oxidising lactate within the muscle itself. both theories lack universal support, however, the use of compression socks are fairly common among athletes. the aim of this study was to determine if the measurement of post-exercise muscle oxygenation will shed more light on the physiological mechanism at work during recovery with compression socks. eleven male recreational long-distance runners (30 to 40 years) voluntarily took part in the study. the participants completed three 10 km submaximal runs on the treadmill (80% of peak treadmill velocity) under three conditions and in random order (compression socks, flight socks, no socks). during a 60 min passive recovery period, near-infrared spectroscopy (nirs) was used to measure muscle oxygenation variables (oxyhaemoglobin (o2hb), deoxy-haemoglobin (hhb), and total haemoglobin index (thi)), while maintaining the sock condition of the run. statistically significant (p 0.05) in oxygenation levels in the blood between the compression conditions (cs = -187.0%; fs = 198.0%; -108.0%), thus compression did not cause an increase in arterial flow to the muscle. however, thi was significantly higher with the compression socks compared with the other two conditions, suggesting a significant shift in blood flow from the superficial to the deep veins because of compression. mailto:steve_dh1989@hotmail.com mailto:fcdutoit85@gmail.com mailto:lgrobler@sun.ac.za we therefore hypothesize that the external pressure provided by the compression socks to the calf muscle causes greater extraction of oxygen from the blood, which supports the theory that post-exercise recovery with compression socks is enhanced by the retention of metabolic byproducts in the muscle for oxidation and regeneration of atp. o13: statistical methods to explore the relationship between illness and injury in the super rugby tournament charl janse van rensburg1, esme jordaan1 2, martin s. schwellnus3 4 5, audrey jansen van rensburg3 1biostatistics unit, south african medical research council, 2statistics and population studies department, university of the western cape, parow, south africa, 3sport, exercise medicine and lifestyle institute (semli) & section sports medicine, faculty of health sciences, university of pretoria; 4international olympic committee (ioc) research centre, south africa; 5emeritus professor of sport and exercise medicine, faculty of healht sciences, university of cape town, south africa presenting author e-mail address: charl.jansevanrensburg@mrc.ac.za background: the epidemiology of injuries and illness in rugby union players is well documented. we are not aware of any studies that addressed a possible relationship between injuries and medical illness. objectives: the aim of this study is to develop statistical methods that can be used to explore a possible relationship between illnesses and injuries among the players of the south african super rugby teams over a 4-year period. methods: daily injury and illness data from 869 consenting south african super rugby players who participated in a 4 year (2013-2016) prospective study was used as the principle dataset for this exploratory study. the number (and %) of all the players that suffered from both an illness and an injury were included in the analysis. the observed agreement between illness and injury is reported and kappa is reported as a measure of agreement for each year, as well as combined over the 4 years. the main outcome is the risk of an injury when an illness was also observed in the same player during the tournament (risk ratio, 95%ci). results: the number (and %) of ill (il) and injured (ij) players in each year was as follows: 2013 [il=58 (32.2%); ij= 90 (50.0%)], 2014 [il=75 (38.1%); ij=103 (52.3%)], 2015 [il=86 (39.5%); ij=110 (50.5%)] and 2016 [il=75 (27.4%); ij=111 (40.5%)]. the measure of agreement (kappa) between illness and injury occurrence for each year was as follows: 2013=0.11, 2014=0.16, 2015=0.14 and 2016=0.28. the overall kappa for the 4-year period was 0.18. the risk ratio (with 95%ci) for injury when an illness was observed in the same year was as follows: 2013=1.3 (1.0-1.7), 2014=1.4 (1.1-1.8), 2015=1.3 (1.0-1.7) and 2016=2.0 (1.6-2.6). the overall risk ratio for injuries when an illness was observed for the 4-year period was 1.5 (1.3-1.7). conclusions: the overall agreement between injury and illness status in super rugby players over 4 years is 18%. in players with an illness during the tournament, the risk ratio of having an injury in the same tournament is 1.5. o14: the injury and illness profile of 23055 participants in a 94.7km cycle race cross-sectional study dina christina janse van rensburg1, mia breedt1, lizelle fletcher1, catharina c. grant1 1university of pretoria presenting author e-mail address: christa.jansevanrensburg@up.ac.za introduction: the momentum 94.7 cycle challenge is an annual recreational long distance cycling event in south africa. medical support at such an event is imperative, with little known regarding the risk of acute traumatic injuries and acute medical illness. purpose: to describe the incidence and patterns of acute injury and medical illness and difference between sexes during a mass community cycling race. methods: a descriptive study of the 2014 momentum 94.7 cycle challenge, documenting the incidence of acute traumatic injuries and acute non-traumatic medical illness in 23055 race starters (males=17520, females=5236, not specified=299) during the 94.7km distance. results: an incidence (per 1000 starters) of 38.69 (females=38.39, males=36.52) for all medical illness; with an incidence of 11.88 (females=16.42, males=10.73) for adverse medical events and of 1.3 (females=2.67, males=0.86) for serious adverse events, were reported. the incidence of non-traumatic medical complaints was 32.48 (females=31.32, males=33.39) and of traumatic injuries was 3.99 (females=7.07, males=3.14). females had a higher risk of sustaining traumatic injuries (p50yrs (p=0.0002), had a higher risk for traumatic injuries. conclusions: a reported ratio of 1:26 (females=1:26, males=1:28) of all starters developed medical complaints; with 1:84 cyclists (females=1:61, males=1:93) that developed adverse events and did not finish the race; and 1:769 participants (females=1:374, males=1:1163) developing serious adverse events that required hospitalisation. the majority of admissions for traumatic injuries were followed by cardiovascular complaints. a wide spectrum of medical complaints can be expected during mass recreational sport events, with a higher risk for females to sustain traumatic injuries, and encounter central nervous system and eye complaints. the majority of disorders involved the musculoskeletal system. information regarding the pattern and type of medical encounters can prove useful during planning and management of similar future events. o15: infections of the respiratory tract account for >50% of all illness during the super rugby union tournament – a prospective study involving 80 088 player days audrey jansen van rensburg1, martin p schwellnus 1 2 3, dina christina janse van rensburg1, esme jordaan4 1sport, exercise medicine and lifestyle institute (semli) & section sports medicine, faculty of health sciences, university of pretoria, 2international olympic committee (ioc) research centre, south africa, 3emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa, 4 biostatistics unit, south african medical research council; statistics and population studies department, university of the western cape presenting author e-mail address: audrey.jansenvanrensburg@up.ac.za background: illness accounts for a significant proportion of consultations with a team physician travelling with elite athletes. the purpose of this study is to determine the incidence, type, and severity (time loss >1 day) of illness in rugby union players participating in the annual 20-week super rugby tournaments. methods: a cohort of 869 elite rugby players from 5 south african teams participating in the super rugby tournaments each year, from 2013 to 2016, were recruited. all players were followed daily over the 20-week competition period for each year (80 088 player days over 4 years). the team physicians completed an illness log with 100% compliance on every day of the annual competition period. information included the daily squad size and illness details including system affected, suspected cause (infection or not), and training/match days lost. results: the incidence of illness (illness per 1000 player days) in rugby players in the 4-year period were as follows: a total of 389 illnesses were reported, resulting in an overall crude incidence rate of illness of 4.9 / 1000 player days (95% ci, 4.4–5.4). the highest proportion of all illness (% mailto:charl.jansevanrensburg@mrc.ac.za mailto:christa.jansevanrensburg@up.ac.za mailto:audrey.jansenvanrensburg@up.ac.za of all illness) was in the respiratory system (69.7%) followed by illness in the gastro-intestinal system (20.1%). an infection was the suspected cause of illness in 75.3% of all illness, with infections in the respiratory system accounting for 55.0% of all illness. a time loss of >1 day was reported for 33.5% of all illness. conclusion: during the super rugby tournament, infective illness involving the respiratory tract, accounts for more than 50% of all illness. future studies should therefore be directed at determining risk markers for infections in the respiratory tract, so that preventative measures can be designed and implemented to protect the health of these athletes. o16: 13.3% runners use prescription medication, mostly to treat hypertension, raised serum lipids, depression and asthma: a crosssectional study in 76 654 distance runners marcel jooste1, martin schwellnus2 3 4, sonja swanevelder5, esme jordaan5 6 1intern, east london hospital complex, east london, 2sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, south africa; 3international olympic committee (ioc) research centre, south africa; 4emeritus professor, faculty of health sciences, university of cape town, south africa, 5biostatistics unit, south african medical research council, 6statistics and population studies department, university of the western cape, , presenting author e-mail address: joostemarcel@gmail.com introduction: the evidence that considerable health benefits are associated with regular exercise is irrefutable and participation in mass community-based distance running events should be encouraged. entrants to these events are older and therefore more likely to have underlying medical conditions and use chronic prescription medication. however, data on the use of chronic prescription medication in distance runners is limited. chronic prescription medication can be associated with increased risk of medical complications during exercise. the purpose of this study is to determine the prevalence of use of chronic prescription medication in 21.1km and 56km runners and to determine the most common types of medication used. methods: 76 654 consenting participants in the two oceans marathon races (21.1km=47 069; 56km=29 585) were studied from 2012 2015. chronic prescription medication use, and type of medication (12 categories) were self-reported as part of an online pre-race medical screening and intervention system administered during the race entry process. crude (un-adjusted for age, sex) frequencies (% runners; 95% ci) of chronic prescription medication use and type are reported. results: overall, 10 188 (13.3%; 13.1-13.5) runners reported using chronic prescription medication and this was significantly higher in 21.1km (14.1%; 13.8-14.4) vs. 56km (12.0%; 11.6-12.4) runners (p80% of runners, were anti-hypertensive medication (24.4%; 23.5-25.2), lipid lowering medication (23.4%; 22.5-24.2), anti-depressants (20.0%; 19.2-20.8), and asthma medication (13.0%; 12.4-13.7). conclusion: 1 in 8 runners use chronic prescription medication at the time of entry for an event, mostly to treat four conditions: hypertension, raised serum lipids, depression and asthma. all these categories of medication may influence exercise performance and/or alter the risk of medical complications during high-intensity, prolonged exercise. o17: novel direct and indirect effects of risk factors for exercise associated muscle cramping (eamc) in a cohort of 47784 distance runners over 4 years esmè jordaan1, martin schwellnus2 3 4 1biostatistics unit, south african medical research council and statistics and population studies department, university of the western cape 2institute for sport, exercise medicine and lifestyle research & section sports medicine, faculty of health sciences, university of pretoria, south africa; 3international olympic committee (ioc) research centre, south africa; 4emeritus professor, faculty of health sciences, university of cape town, south africa presenting author e-mail address: esme.jordaan@mrc.ac.za background: we recently identified novel risk factors for eamc in distance runners, including age, gender, a history of heart diseases, medication use for heart disease, training (number of years being a runner), racing distance (21km/56km), symptoms of running injuries and medication use for injuries. the relationships between these risk factors for eamc are over-simplified, and complex path relationships between these risk factors and eamc have not been investigated. objective: the objective of the analysis was to explore the complex relationships among the risk factors associated with eamc by means of path analysis, in order to identify significant paths and to estimate direct as well as indirect path relationships between the risk factors and eamc. in addition, we sought to explore total effects by aggregating the direct and indirect effects. type of study path analysis of prospective data. design and setting 47784 runners (21km/56km) took part in one (62%), two (22%), three (11%) or four (5%) years of a 4-year prospective cohort study from 2012 to 2015. data was collected via 76654 questionnaires. main outcome measurements: indirect, direct and total path estimates of the predictors of eamc in distance runners. results: direct predictors of eamc included a history of/medication use for cvd (p=0.0001), training/competition load (p=0.0001), and age (p= 0.0001). gender was an indirect predictor operating mainly through training/competition load (73%) and to a lesser extent through a history of/medication use for cvd (28%) (p=0.0001). additionally, training/competition load is a predictor of a history of/medication use for cvd as well as symptoms/medication use for injuries (p=0.0001). however, for a history of/medication use for cvd the estimate is negative (estimate=0.310, se=0.022) and for symptoms of/medication use for injuries the effect is positive (estimate=0.698, se=0.021) conclusion: using a path analysis approach, novel risk factors for eamc (indirect and direct relationships) were identified, indicating that the risk factors associated with eamc are complex. indirect risk factors do not impact directly on eamc, but rather through their effects on direct risk factors. these data enable clinicians to better understand these complex relationships of risk factors and can apply this to knowledge in the prevention, diagnosis and management of eamc in athletes. o18: prevalence and modifiable intrinsic risk factors for anterior knee pain among runners in peri-urban communities in ekurhuleni, gauteng province siyabonga kunene1, serela ramklass2, nomathemba taukobong3 1university of the witwatersrand, 2university of kwazulu-natal, 3sefako makgatho health sciences university presenting author e-mail address: siyabonga.kunene@wits.ac.za mailto:joostemarcel@gmail.com mailto:esme.jordaan@mrc.ac.za mailto:siyabonga.kunene@wits.ac.za introduction: anterior knee pain (akp) is the most common injury experienced by runners and is prevalent among females, young adults and adolescents. several modifiable intrinsic risk factors have been suggested to contribute to akp. aim: to determine the prevalence and modifiable intrinsic risk factors for akp among runners in peri-urban communities in ekurhuleni, gauteng province. methods: a cross–sectional study design was used. population comprised of 347 runners from six developing running clubs. convenient sampling method and a raosoft statistical tool were used to recruit and calculate a representative sample size of 183 participants, taking into consideration a 95% confidence level. participants included runners aged between 13 and 55-year-old with no history of degenerative and traumatic injuries. standardized anterior knee pain questionnaire was used to determine akp prevalence and 12 physical tests were used to screen for modifiable intrinsic risk factors. ethical clearance was granted and consent by participants was obtained. data were collected over three months and spss was used to obtain descriptive (frequencies) and inferential statistics (logistic regression). results: participants were dominated by males (57.9%), youth (18-35 years) and those with 3 5 years of running experience (31.1%). anterior knee pain accounted for 40% among participants. modifiable intrinsic risk factors for akp were found present among many runners (over 50%). older (36-55 years) and more experienced (>10 years) participants were less likely to contribute to akp compared to younger (13-17 years) and less experienced (<1 year) (or=0.341, p=0.037 and or=0.207, p=0.028 consecutively). gluteus muscle weakness, patellar tilt and patellar glide problems on the right side of the body were less likely to contribute to akp (or=0.378, p=0.027; or=0.304, p=0.027 and or=0.051, p=0.043 consecutively). conclusion: study showed a high presence of akp and modifiable intrinsic risk factors. a comprehensive multidisciplinary approach programme is highly reccommended for the managment of akp and its associated risks among the population. key words: anterior knee pain, prevalence, modifiable intrinsic risk factors, runners o19: barriers to concussion management in low-income countries. uganda as a case study samuel lubega1, mike lambert1 1university of cape town presenting author e-mail address: lubegasmlk41@gmail.com background: the management of concussed athletes is topical in the developed world and best practice guidelines representing several sports have been developed. whether these guidelines have been adopted in the developing world is not known. aim: to identify the barriers to appropriate health care of a concussed athlete in a developing country, using uganda as an example. the study objectives were to identify concussion injuries in a variety of sports in uganda, and to monitor the circumstances of treatment until the athlete returned to full sports participation. methodology: a mixed study design using an injury management data extraction form, facility checklists, and knowledge and practice of sports service providers’ questionnaire and an interview guide. data were collected over eight months and analysed using the stat version 64, and presented as frequencies and percentages. the qualitative data were analysed using a thematic and content analysis method. results: a total of 75 injuries were documented within a period of six months. three cases of concussion (4%) were followed from the injury to return to full sports participation. none of the concussed athletes had undergone pre-participation evaluation before the competition. there were no diagnostic tests carried out at the time of injury and no return-to-play protocol advice was provided at the medical facilities. the study established that there was insufficient knowledge and appropriate practices during emergency care and intermediate care stages of concussion management. there was no national sports health care policy guideline regarding management of concussion injuries. conclusion: this study exposes the lack of care and management of concussed athletes in uganda. the following steps could improve concussion management: (i) create a national awareness campaign about concussion; (ii) develop a national concussion policy guideline; (iii) train more medical specialists in concussion management and other sports-related injuries. o20: the effect of progressive resistance exercise intervention on hiv infected individuals taking antiretroviral therapy (art) in zimbabwe victor mbayo1, takshita sookan1 1university of kwazulu-natal-discipline of biokinetics, exercise and leisure sciences presenting author e-mail address: vmbayo@gmail.com introduction: hiv infected individuals initiating art increase their life expectancy, however the arts result in an increased risk of chronic diseases. resistance exercise (re) interventions address modifiable risk factors brought about the adverse effects of art in hiv infected. the study investigated effect of res on body composition (bc), chronic disease risks and strength of this patient population. methods: quasi-experimental pre-and-post-test design was followed. a sample of 128 male and female hiv infected, on art, 18-45 years, black african ethnic groups, in harare, were recruited and randomly assigned to experiment (pre n=64) group performing res 3days/week or control (con n=64) group, for 12 weeks. anthropometric (bc), chronic disease risk (bp, blood glucose, blood cholesterol) and strength (1rm) markers were pre-and-post measured in all participants observing standard protocols. chi-square, fisher’s test, linear regression, binomial test, spearman’s and pearson’s correlations were conducted, with statistical significance at p0.05. results: there were significant differences in post-test chronic disease risks between pre and con group after correcting for pre exercise scores, p.0005. post-test blood cholesterol and glucose measures in con group were significantly higher [4.672(±0.497) and 3.98(±0.818) mmol/l] than pre group [4.240(±0.488) and 2.49(±1.846) mmol/l]. a 100% of con group participants remained with pre-hypertension at post-test while 66% of pre group with hypertension 2 had hypertension 1 at post-test. post-test bc (w/hip ratio, bmi, %bf) remained high in con group and improved significantly in pre group p0.05. strength levels in pre group members significantly increased for bench press, squats, bicep curls and leg curls p0.05 than con group. conclusion: the results showed that the resistance exercise programme improved their bc, chronic disease risk and strength in hiv infected individuals on art. res are safe and beneficial for hiv infected individuals in resource constrained settings. therefore, policy makers in zimbabwe can utilise this information to include re programs for hiv infected as a healthy lifestyle intervention. key words: hiv, art, chronic disease risks, resistance exercises, body composition, strength mailto:lubegasmlk41@gmail.com mailto:vmbayo@gmail.com o21: selected motor fitness test scores for rural emergency medical and rescue services (emrs) personnel in the north west province solomon mthombeni1, yoga coopoo1 1department of sport and movement studies, university of johannesburg presenting author e-mail address: smthombeni.solly@gmail.com introduction: the occupation of emergency care personnel (ecp) places high mental and physical demands on the body. ecps perform a range of vigorous tasks on demand in a pre-hospital environment as quickly and efficiently as possible. there is limited data on occupational demands of ecps although recent studies indicate an association between low fitness levels and premature rescuer fatigue during cpr and increased incidence of musculoskeletal injuries. the objective of the study was to determine the physical characteristics of ecps through the administration of a motor fitness test battery. methods: ninety one ecps volunteered to take part in the study (64 males, 27 females). health questionnaires, morphological measurements and nine field tests were administered to subjects. the data collected was subjected to statistical analysis using a computer programme. scores were compared to available norms. results: descriptive statistics were used to analyse the data. means recorded were age 36.7(±5.4), bmi 28.4(±5), bf% 25.7(±7.4), waist circumference 90.7(±11.3), waist/hip ratio 0.86(±0.06), rhr 96(±16), sbp 122(±15), dbp 91(±11), bg 5.1(± 2.4), tc 4.89(±0.71). means for field tests included trunk flexibility msr (35.3±8), muscular strength (grip 40±9), isometric torso lift 101(±28) and squat 106(±30) kg. local muscular endurance including push ups to failure, flexed arm hang (seconds) and 60 seconds sit up produced means of 21(±4), 27(±19) and 26(±11) respectively. means for anaerobic (250m shuttle runs) and aerobic capacity (12 minute walk/run) were 73(±15) seconds and 1844(±416) meters resulting in a predicted vo2max of 29.9(±9.3)ml/kg/min. high levels of overweight (36%), obesity (36%), low levels of aerobic capacity (76%), grip (75%), lower body strength (72%) and local muscular endurance (push ups 36%, sit ups 67%) were found among ecps. cardiov ascular risk factors were hypertension (21%), abdominal obesity (25%), high bf% (55%), bg (ifg 30%, igt 6%) and elevated tc levels (35%). conclusion: most results obtained showed poor levels of fitness as compared to other occupations and was inadequate for practicing ecp’s. physical fitness and healthy lifestyle interventions need to be implemented for ecps thereby improving occupational fitness, lowering musculoskeletal injury and cardiovascular risk. normative data should be established to conduct regular workplace fitness assessments of ecps. o22: high intensity interval training and detraining effects on cardio-metabolic profiles of young overweight and obese women privilege b.m ndlovu, prof elmarie terblanche presenting author e-mail address: ndlovu.privilege@gmail.com almost 57% of south african adult women are overweight or obese. regular exercise, has been shown to facilitate weight loss, however, people usually cite lack of time as a barrier to sustained participation. high intensity interval training (hiit) is not only a time-efficient exercise to improve aerobic fitness and cardio-metabolic risk factors, but it is also safe for those with poor health and fitness levels. since there is a paucity of research on women populations, the aim of this study was to investigate the training and detraining effects of a short-term hiit programme on selected health-related measures in young overweight and obese women. twenty women volunteered to participate in the study. they performed six sessions of hiit (1015 x 1 min running bouts at 90% hrmax), separated by 1 min recovery at 50-60% hrmax, followed by two weeks of detraining. testing was done before and after the exercise intervention and after detraining. the outcome variables included resting glucose, total cholesterol, blood pressure, fat mass, lean mass and maximal aerobic capacity (vo2max). although the dietary intake of the women was not monitored, they were asked to maintain the same diet thro ughout the experimental period. there was a statistically significant decrease in body mass (1.6%, p 0.001), fat mass (3.7%, p 0.001) and waist circumference (4.8%, p 0.001), and an increase in lean mass of 1.9% (p 0.001) following the training intervention. there was a decrease in resting blood glucose (11%, p 0.001), total cholesterol (10.4 %, p 0.01), systolic (3.4%, p 0.001) and diastolic blood pressure (5.8%, p 0.001), as well as an increase in vo2max after the six training sessions. following detraining, the metabolic adaptations after hiit were either maintained, or at least not completely reversed. hiit resulted in significant weight loss and improved cardio-metabolic health of overweight and obese women. the fact that most of the weight loss was due to a reduction in fat mass was a surprising finding. the minimal exercise time per session and positive results within a short period should be highly encouraging for women wishing to lose fat mass. o23: about 1/8 runners report a non-traumatic injury annually, and >50% of these significantly affect training: a cross-sectional study in 29 585 56km runners menzi ngcobo1, martin schwellnus2 3 4, paola wood1, sonja swanevelder5 1sport, exercise medicine and lifestyle institute (semli) and division of biokinetics and sports science, department of physiology, faculty of health sciences, university of pretoria, south africa, 2sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, south africa; 3international olympic committee (ioc) research centre, south africa; 4emeritus professor, faculty of health sciences, university of cape town, south africa, 5biostatistics unit, south african medical research council, presenting author e-mail address: menzi.ngcobo@up.ac.za introduction: participation in ultra-marathons has become increasingly popular, but there is an inherent risk of injury in these runners. there are little data on the epidemiology of non-traumatic (chronic, “overuse”) injuries (nti) in ultra-marathon runners. the purpose of the study is to determine the lifetime prevalence, annual incidence, anatomical areas and severity of nti’s in a large cohort of runners participating in a 56 km ultra-marathon. methods: a cross-sectional study was conducted in runners participating in the 56km two oceans marathon races between 2012-2015. 29 585 runners gave consent that their online pre-race medical questionnaire data could be used for research. these data included information on nontraumatic (overuse) injuries they experienced in the 12months prior to registration. we report the crude (un-adjusted) (%; 95%ci) lifetime prevalence, annual incidence, common anatomical areas, specific nti’s, and severity of ntis in runners. results: in total, 6608 (22.3%; 21.9-22.8) runners reported a nti during their running careers. of the runners reporting a lifetime injury, 58.9% (57.7-60.1) reported a nti in the previous year (retrospective annual incidence). the most common anatomical regions affected by nti in runners reporting a nti in the previous 12 months were the following: knee (20.9%; 19.6-22.2), calf (12.0%; 11.0-13.1) and the achilles tendon area (9.4%; 8.5-10.3). most nti’s were muscle tissue injuries (42.1%; 40.6-43.7) followed by tendon (25.1%; 23.7-26.4), and ligament injuries (11.0%; 10.0-12.0). the most common specific ntis were iliotibial band (itb) syndrome (16.2%; 15.0-17.3), calf muscle injury (10.8%; 9.8-11.7) and mailto:smthombeni.solly@gmail.com mailto:ndlovu.privilege@gmail.com mailto:menzi.ngcobo@up.ac.za achilles tendinopathy (9.7%; 8.8-10.7). 54.3% (52.7-55.9) of nti’s were severe enough to interfere with training or competition, and the preferred choice of treatment modality was rest (67.0%; 65.5-68.4). conclusion: about 1 in 8 runners (56km) report a non-traumatic injury in the last year. these injuries affect mostly the knee, calf and achilles tendon and 54% injuries are severe enough to affect training and competition. o24: the effect of therapeutic horseback riding on heart rate variability of children with disabilities zingisa nqwena1, dr rowena naidoo1 1discipline of biokinetics, exercise and leisure sciences, school of health sciences, university of kwazulu-natal, durban, south africa presenting author e-mail address: zingisanqwena@gmail.com introduction: heart rate variability (hrv) is the oscillation in the interval between consecutive heart beats, resulting from dynamic interplay between multiple physiologic mechanisms that regulate instantaneous heart rate. short-term heart rate regulation is governed by sympathetic and parasympathetic neural activity and therefore hrv examination can be used as a non-invasive estimate of the functioning of the autonomic nervous system (ans). aim: to determine the effects of therapeutic horseback riding (thr) intervention on the hrv of children with disabilities. the objective was to examine if thr intervention improves the hrv of children, hence improving the parasympathetic activity that is associated with a calm and relaxed state. methods: this is a quasi-experimental design. heart rate variability components were measured over six intervention sessions of thr. heart rate variability measures were recorded from 29 participants with various disabilities, and was assessed in both time and frequency domains. results: over the six thr sessions, the time domain showed an increase in hrv for pre-thr indicating improved vagal activation, whereas frequency domain showed both increased sympathetic activity and increased parasympathetic activation during thr based on different components of frequency domain. conclusion: therapeutic horseback riding intervention of six sessions demonstrated a change in hrv of children with disabilities. however, the changes obtained were not significant to make conclusive measures as to whether sympathetic or parasympathetic activity is predominantly increased after the six sessions. further research involving more than six sessions of thr is required to yield more significant changes. o25: the biomechanical evolution of a portable muscle testing device (pab®), using air pressure as a biofeedback and strength testing tool a new innovation. andre pienaar1 1biokineticist presenting author e-mail address: bodybio@netactive.co.za the pressure air biofeedback device (pab®) was developed, researched and validated through a clinical phd study; however its application was limited to the strength assessment of the lumbar spine only. for this purpose, the pab® device was further developed by addin g new air-filled devices (togu, germany) to the device, allowing it to measure a wider range of muscle groups of the body. previously, the pab® device only made use of an air-filled elastic ball to assess isometric strength of the lower back. however, the new togu air-filled devices have been used in an innovative way to measure muscle performance of the shoulder, chest, arm, hand, hip, thigh and posture. eleven (11) new muscle performance tests have been added to the pab® muscle testing protocol. the togu air-filled devices consist of the air grip roll, pull ring, touch ball and air sit cushion. the validity of these togu air-filled devices was assessed by comparing a selected measure, air pressure force in millibar (mb), to a standard criterion; calibrated weights in kilograms (kg) during day to day tests. a highly significant relationship was found between air pressure output (mb) of all the togu air-filled devices and calibrated weights (kg). apart from validating these air-filled devices, a conversion factor for three of the togu air-filled devices, used for measuring muscle strength, has also been calculated. inter-pull ring calibration testing indicated a highly significant correlation between togu pull rings. this study shows the usefulness and great promise of the new pab® device and may be used in rehabilitation interventions to provide air pressure biofeedback results to patients. however, specific clinical validation and reliability studies are left as future work. keywords: pab®, air pressure, calibration, validity, togu air-filled devices o26: oral supplementation of specific collagen peptides accelerates improvement in achilles tendon symptoms and function in combination with eccentric exercise. sfe praet1, c. purdam2, l. burke3, m. welvaert4, g. lovell1, l. dixon2, j. gaida5, s. manzanero1, n. vlahovich1, d. hughes1, g. waddington1 dept of 1sport medicine, 2physiotherapy, 3sports nutrition, australian institute of sport, canberra, australia, dept of physiotherapy, 4ucrise, university of canberra, canberra, australia, 5discipline of physiotherapy, university of canberra, canberra, australia. presenting author e-mail address: stephan.praet@ausport.gov.au introduction: recent studies indicate that nutritional factors can modulate local tendon healing following mechanical overloading. at a histological level tendinopathy is characterised by an imbalance in tendon collagen synthesis and structural fibril degradation. the current pilot study aimed to investigate whether oral supplementation of specific collagen peptides (scps) improves achilles tendon symptoms and function in patients with chronic achilles tendinopathy. methods: the current pilot study was a prospective double-blinded placebo-controlled clinical trial with a cross-over design. eligible participants were randomized to 3 months of bi-daily doses of 2.5g scps (tendoforte®, gelita ag, germany) or a placebo before exercise. group ab received cps for the first 3 months before crossing over to placebo. group ba received placebo first before crossing over to scps. in addition to the nutritional intervention, all participants followed a well-structured eccentric calf strengthening program and milestone-based return-torunning program for 6 months. at baseline (t1), 3 (t2) and 6 (t3) months, visa-a questionnaires were obtained in 20 patients (13 men/7 women, age:44±8 yrs, bmi:24.4±3.3kg.m-2) with clinical symptoms (duration 54±90 months) of unior bilateral achilles tendinopathy. results: after 3 months, 6 out of 10 participants in group ab and 3 out of 10 participants in group ba successfully returned to running activities. after 6 months these numbers further increased to respectively 7 (group ab) and 5 (group ba) participants. visa-a score for the ab group at t1 was on average 60.8 (95%ci:[52.0;69.6]), similar to the ba group at t1 (62.8, 95%ci: [54.0;71.6]). at t2 the visa-a score increased significantly for the ab group (73.4, 95%ci:[64.6;82.2]), while in the ba group there was only a small increase (68.1, 95%ci:[59.3;76.9]). at t3, the ab group showed a further non-significant increase in visa-a (79.3, 95%ci:[70.5;88.1]), while the ba group showed a significant increase in visa-a (85.8, 95%ci: [77.0;94.6]). both groups achieved the same improvement between t1 and t3. mailto:zingisanqwena@gmail.com mailto:bodybio@netactive.co.za mailto:stephan.praet@ausport.gov.au discussion & conclusion: although this pilot study has limited statistical power and requires duplication in a larger clinical trial, oral supplementation of scps may accelerate the clinical benefits of a well-structured calf strengthening and return-to-running program in patients with chronic achilles tendinopathy symptoms. o27: one night of partial sleep deprivation impairs recovery from a single exercise training session dale rae1, tayla chin1, kagiso dikgomo1, andrew mckune2 1division of exercise science and sports medicine, university of cape town, 2research institute for sport and exercise, university of canberra presenting author e-mail address: dale.rae@uct.ac.za purpose: the effects of sleep deprivation on physical performance are well documented, but data on the consequence of sleep deprivation on recovery from exercise are limited. the aim was to compare cyclists’ recovery from a single bout of high intensity interval training (hiit) after which they were given either a normal night of sleep (con, 7.56±0.63h) or half of their usual time in bed (dep, 3.83±0.33h). methods: in this randomized cross-over intervention study, 16 trained male cyclists (age: 32±7y, relative peak power output (ppo: 4.6±0.7wkg1) performed a hiit session at ±18:00 followed by either the con or dep sleep condition. recovery from the hiit session was assessed the following day by comparing pre-hiit variables to those measured 12h and 24h after the session. following a two-week washout, cyclists repeated the trial but under the alternate sleep condition. results: ppo was reduced more 24h after the hiit session in the dep (δppo: -0.22±0.22w·kg-1; range: -0.75 to 0.1w·kg-1) compared to the con condition (δppo: -0.05±0.09w·kg-1, range: -0.19 to 0.17w·kg-1, p=0.008, d=-2.16). cyclists were sleepier (12h: p=0.002, d=1.90; 24h: p=0.001, d=1.41) and felt less motivated to train (12h, p=0.012, d=-0.89) during the 24h recovery phase when the hiit session was followed by the dep condition. the exercise-induced 24h reduction in systolic blood pressure observed in the con condition was absent in the dep condition (p=0.039, d=0.75). conclusions: one night of partial sleep deprivation impairs recovery from a single hiit session in cyclists. further research is needed to understand the mechanisms behind this observation. o28: 13% of 56km, and 4% of 21.1km runners use analgesic/anti-inflammatory medication during events: a cross-sectional study of 76 654 distance runners adrian rotunno1, martin schwellnus1 2 3, christa janse van rensburg1, sonja swanevelder4 1sport exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa, 2international olympic committee (ioc) research centre, south africa; 3emeritus professor, faculty of health sciences, university of cape town, south africa, 4biostatistics unit, south african medical research council presenting author e-mail address: adrian.rotunno@gmail.com introduction: mass participation distance running events have increased in popularity. distance running is associated with a risk of injuries, and there is some evidence that runners use analgesic/anti-inflammatory medication (aam) during events that may compromise their health. however, there are few data on actual patterns of aam use by runners. the purpose of this study is to determine the prevalence of aam use in 21.1km and 56km marathon runners, as well as any differences in usage patterns between 21.1km and 56km runners. methods: 76 654 consenting participants in the two oceans marathon races (21.1km=47 069; 56km=29 585) were studied from 2012-2015. data on aam use (7 separate medication types) from an online pre-race medical screening and intervention system administered during the race entry process were analysed and crude (un-adjusted for age, sex) frequencies (% runners; 95% ci) of aam use and type are reported. results: a total of 8 288 (10.8%; 10.6-11.0) runners reported using aam in the week before an event, and this was significantly higher in 56km (16.0%; 15.6-16.5) vs. 21.1km (7.5%; 7.3-7.8) runners. 56km runners also used significantly more pain medication during an event (13.6%, 13.214.0) compared to 21.1km runners (4.1%, 3.9-4.3). the most common type of aam used in the week before an event was non-steroidal antiinflammatory drugs (nsaids), and use was significantly higher in 56km (9.7%; 9.4-10.1) vs. 21.1km (4.7%; 4.5-4.92). similarly nsaids use was the most common type of aam used during an event and this was also significantly higher in 56km (6.9%; 6.6-7.2) vs. 21.1km (2.1%; 1.9-2.2) runners. conclusion: 10% of the total runners reported use of analgesic/anti-inflammatory medication in the week before an event, while use during an event was 13.6% and 4.1% for 56km and 21.1km runners respectively. the most common medication type used by both 21.1km and 56km runners were the nsaids. these medications have the potential to negatively influence health, and performance of the athletes, and may be associated with increased risk of medical complications during events. o29: high pre-competition injury rate dominates the injury profile at the rio 2016 summer paralympic games: a prospective cohort study of 51,198 athlete days phoebe runciman1, wayne derman1, prof martin schwellnus2 3, esme jordaan4 1institute of sport and exercise medicine, department of surgical sciences, stellenbosch university, international olympic committee (ioc) research centre, south africa., 2sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria; 3international olympic committee (ioc) research centre, south africa., 4biostatistics unit, medical research council of south africa, statistics and population studies department, university of the western cape presenting author e-mail address: phoebe.runciman@gmail.com objectives: to describe the incidence of injury in the pre-competition and competition periods of the rio 2016 summer paralympic games. methods: a total of 3657 athletes from 78 countries, representing 83.4% of all athletes at the games, were monitored on the web-based injury and illness surveillance system over 51,198 athlete days during the rio 2016 summer paralympic games. injury data were obtained daily from teams with their own medical support. results: a total of 510 injuries were reported during the 14 day games period, with an injury incidence rate (ir) of 10.0 injuries per 1000 athlete days (12.1% of all athletes surveyed). the highest irs were reported for football 5-a-side (22.5), judo (15.5) and football 7-a-side (15.3) compared with other sports (p 0.05). pre-competition injuries were significantly higher than in the competition period (risk ratio: 1.40, p 0.05), and acute traumatic injuries were the most common injuries at the games (ir of 5.5). the shoulder was the most common anatomical area affected by injury (ir of 1.8). mailto:dale.rae@uct.ac.za mailto:adrian.rotunno@gmail.com mailto:phoebe.runciman@gmail.com conclusion: the data from this study indicate that a) irs were lower than those reported for the london 2012 summer paralympic games, b) the sports of football 5-a-side, judo and football 7-a-side were independent risk factors for injury, c) pre-competition injuries had a higher ir than competition period injuries, d) injuries to the shoulder were the most common injuries. these results would allow for comparative data to be collected at future editions of the games and can be used to inform injury prevention programs. o30: sport, gender and age increase risk of illness at the rio 2016 summer paralympic games: a prospective cohort study of 51,198 athlete days phoebe runciman1 2, wayne derman1 2, prof martin schwellnus 2 3, esme jordaan4 1institute of sport and exercise medicine, department of surgical sciences, stellenbosch university, 2international olympic committee (ioc) research centre, south africa, 3sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, 4biostatistics unit, medical research council of south africa, statistics and population studies department, university of the western cape presenting author e-mail address: phoebe.runciman@gmail.com objective: to describe the epidemiology of illness at the rio 2016 summer paralympic games. methods: a total of 3657 athletes from 78 countries, representing 83.5% of all athletes at the games, were monitored on the web-iiss over 51, 198 athlete days during the rio 2016 summer paralympic games. illness data were obtained daily from teams with their own medical support through the web-iiss electronic data capturing systems. results: the total number of illnesses reported was 511, with an illness incidence rate (ir) of 10.0 per 1000 athlete days (12.4%). the highest irs were reported for wheelchair fencing (14.9), para swimming (12.6) and wheelchair basketball (12.5) (p 0.05). female athletes and older athletes (35-75 years) were also at higher risk of illness (both p 0.01). illnesses in the respiratory, skin and subcutaneous and digestive systems were the most common (irs of 3.3, 1.8 and 1.3, respectively). conclusion: the medical data recorded on the web-iiss in this study show that 1) the rate of illness was lower than that reported for the london 2012 summer paralympic games, 2) the sports with the highest risk were wheelchair fencing, para swimming and wheelchair basketball, 3) female and older athletes (35-75 years) were at increased risk of illness, and 4) the respiratory system, skin and subcutaneous system and digestive system were most affected by illness. these results would allow for comparative data to be collected at future editions of the games and can be used to inform illness prevention programs. o31: runners self-optimize their kinematics in response to running-induced fatigue after eight weeks of endurance training saint sackey1, kurt schütte1 2, rachel venter1 1department of sport science, stellenbosch university, south africa, 2human movement biomechanics research group, dept. kinesiology, ku leuven, leuven, belgium presenting author e-mail address: saintandrewss@yahoo.com background: the incidence rate of running related injuries among recreational runners have been reported to range between 30% 80% per annum. changes in running kinematics as a result of fatigue have been suggested as links to these injuries. it has been theorised that runners would automatically fine tune their running form to be more efficient after a brief exposure to training. this theory however has been investigated by only three studies (gonzález-mohíno et al., 2016; moore et al., 2012; lake and cavanagh, 1996) according to the knowledge of the authors. it is further unclear, how a training intervention could influence the changes in running kinematics associated with fatigue. this article reports on the effects of a customized eight-week endurance training programme on running kinematics. methods: recreational runners (n=16) were administered with an incremental speed to exhaustion protocol (modified koblbauer et al., 2014) before and after an endurance training programme. participants ran at a comfortable speed of (9km for men or 8km for women) for four minutes before and after the fatigue protocol for pre-post fatigue analysis. spatio-temporal kinematic data (contact times, step length, flight times, and stride angle) were collected with an optogait photoelectric system; arm carriage and forward trunk lean were captured with a camera positioned 200cm from the front and the side of the treadmill respectively. results: a two way anova showed a significant reduction in step length (p = 0.03) after the endurance training at post fatigue. contact time increased with a medium effect size of 0.63 and 0.47 (cohen’s) at pre and post fatigue respectively. independent of fatigue, forward trunk lean significantly reduced (p = 0.01) after the endurance training. flight time, stride angle, and arm carriage did not change after endurance training (p > 0.05). discussion and conclusion: this result suggests that training at certain anaerobic thresholds to improve endurance could affect the kinematics of recreational runners. runners appear to self-optimize their running kinematics with running endurance training in response to fatigue. o32: leisure athletes at risk of medical complications: outcomes of online pre-participation screening among 15 778 endurance runners, using current european guidelines safer vi study karen schwabe1, martin schwellnus2 3 4, sonja swanevelder5, esme jordaan5 6 1division of exercise science & sports medicine, department of human biology, faculty of health sciences, university of cape town, south africa, 2sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, south africa; 3international olympic committee (ioc) research centre, south africa; 4emeritus professor, faculty of health sciences, university of cape town, south africa, 5biostatistics unit, south african medical research council, 6statistics and population studies department, university of the western cape presenting author e-mail address: karenschwabe@gmail.com introduction: the european society of cardiology and the european association of cardiovascular prevention and rehabilitation developed guidelines for pre-participation screening of masters and leisure athletes. we determined the prevalence of runners who, according to the proposed guidelines, would require a full medical assessment before participating in a moderateto high-intensity distance running event. methods: 15 778 runners participating in the 2012 two oceans marathon races in south africa completed an online pre-race medical screening questionnaire in line with european pre-participation screening guidelines. results: based on current european guidelines, over 30% of entrants would require a full medical assessment prior to participation. a history of musculoskeletal complaints and the use of prescription medication were the main factors triggering the need for a full medical assessment. risk factors (% runners; 95% ci) for cardiovascular disease (cvd) were present in 16.1% (15.5-16.7) of runners, and 2.3% (2.0-2.5) reported existing mailto:phoebe.runciman@gmail.com mailto:saintandrewss@yahoo.com mailto:karenschwabe@gmail.com cvd. chronic respiratory (13.1%; 12.5-13.6), gastro-intestinal (4.3%; 4.0-4.6), nervous system (3.8%; 3.5-4.1) and metabolic or endocrine (3.5%; 3.2-3.8) conditions were also present. in addition, 13.9% (13.3-14.4) of all the runners had an allergic disease, 14.8% (14.2-15.3) used chronic prescription medication, 15.6% (15.0-16.2) used medication before or during races, and 1.4% (1.1-1.4) had a past history of collapse during a race. conclusion: using current guidelines, a large percentage of runners (>30%) would require full medical assessments before race participation. although this is mainly linked to runners that reported musculoskeletal conditions, cvd risk factors were identified in 16% of runners. we suggest a revision of current guidelines, based on pre-screening data that are linked to serious life-threatening medical complications including sudden cardiac arrest or death during exercise. o33: pre-race medical screening and educational intervention reduces medical complications in distance runners: a prospective study in 153 208 race starters (safer vii) martin schwellnus1 2 3, karen schwabe4, sonja swanevelder5, esme jordaan5 6 1sport exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa; 2international olympic committee (ioc) research centre, south africa; 3emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa, 4division of exercise science & sports medicine, department of human biology, faculty of health sciences, university of cape town, south africa, 5biostatistics unit, south african medical research council, 6statistics and population studies department, university of the western cape presenting author e-mail address: mschwell@iafrica.com introduction: we previously reported a high rate of medical complications (1/121 race starters) and serious (potentially life-threatening) complications (1/1786 race starters) in a cohort of 65 865 runners participating in 21.1km and 56km races over a 4-year period (2008-2011) (safer 1). the purpose of this study is to determine if an online pre-race medical screening and educational intervention program reduces medical complications in distance running events. methods: an online pre-race medical screening (based on the european guidelines for pre-screening of leisure athletes participating in moderateto high-intensity sports) and an educational intervention program was designed and introduced as part of the race registration process, in the period 2012 to 2015 at the two oceans marathon races (21.1km and 56km). the incidence of medical complications (per 1000 race starters; all and serious life-threatening) during the 4-year post-intervention period (2012-2015: 87 343 race starters) was compared with the pre-intervention period (2008-2011: 65 865 race starters). results: compared to the pre-intervention (baseline) period, there was a significant reduction in the incidence (per 1000 starters, 95% ci; adjusted for age group, gender and race distance) of all medical complications in all runners by 29% [pre=8.6 (7.9-9.4); post=6.1 (5.6-6.7), p0.0001], 21.1km runners by 19% [pre=5.1 (4.4-5.9); post=4.1 (3.6-4.8), p=0.0356], and 56km runners by 39% [pre=14.6 (13.1-16.3); post=9.0 (7.9-10.1), p0.0001]. serious life-threatening complications were significantly reduced in all runners by 64% [pre=0.6 (0.5-0.9); post=0.2 (0.10.4), p=0.0003; adjusted for age group and gender]. conclusion: a pre-race medical screening and educational intervention program significantly reduced medical complications and serious lifethreatening complications among all runners in community-based mass participation distance running events. the reduction in all medical complications was significant in both the 21.1km and 56km races. pre-race screening and educational intervention programs could be introduced to reduce medical complications during endurance running events. o34: chronic disease, medication use, history of injuries and running experience are associated with exercise associated muscle cramping (eamc): cross-sectional study in 15 778 distance runners martin schwellnus1 2 3, sonja swanevelder4, esme jordaan4 5, wayne derman2 6 1sport exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa; 2international olympic committee (ioc) research centre, south africa; 3 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa, 4biostatistics unit, south african medical research council, 5statistics and population studies department, university of the western cape, 6institute of sport and exercise medicine, faculty of medicine and health sciences, stellenbosch university, south africa presenting author e-mail address: mschwell@iafrica.com introduction: exercise associated muscle cramping (eamc) is a significant medical complication in distance runners, yet factors associated with eamc are poorly documented. the purpose of this study was to document risk factors associated with eamc in runners. methods: this was a cross sectional study of runners participating in the 2012 two oceans races (21.1km, and 56km). all participants completed a pre-race medical history screening and educational intervention tool. data from 15778 consenting race entrants was analysed, including: training, cardiovascular disease (cvd), risk factors for, and symptoms of cvd, history of diseases affecting major organ systems, cancer, allergies, medication use, and running injury. runners were grouped as having a past history of eamc (heamc group = 2997) and a control group (control = 12781). results: independent factors associated with a higher prevalence ratio (pr) of heamc were any risk factor for cvd (pr=1.16; p=0.0002), symptoms of cvd (pr=2.38; p0.0001), respiratory disease (pr=1.33; p0.0001), git disease (pr=1.86; p0.0001), nervous system or psychiatric disease (pr=1.51; p0.0001), kidney or bladder disease, (pr=1.60; p0.0001), haematological or immune disease (pr=1.54; p=0.0048), cancer (pr=1.34; p=0.0031), allergies (pr=1.37; p0.0001), regular medication use (pr=1.80; p0.0001), statin use (pr=1.26; p=0.0127), medication use during racing (pr=1.88; p0.0001), running injury (pr=1.66; p0.0001), muscle injury (pr=1.82; p0.0001), tendon injury (pr=1.62; p0.0001), and runners in the experienced category (pr=1.22; p0.0001). conclusion: novel risk factors associated with eamc in distance runners were underlying chronic disease, medication use, a history of running injuries and experienced runners. these factors must be identified as possible associations, and therefore be considered in the diagnostic workup, prevention and treatment of eamc. mailto:mschwell@iafrica.com mailto:mschwell@iafrica.com o35: novel risk factors associated with more severe exercise associated muscle cramping (eamc): a cohort study of 41 698 distance runners sonja swanevelder1, martin schwellnus2 3 4 1biostatistics unit, south african medical research council, 2sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, south africa; 3international olympic committee (ioc) research centre, south africa; 4emeritus professor, faculty of health sciences, university of cape town, south africa presenting author e-mail address: sonja.swanevelder@mrc.ac.za introduction: eamc is a common clinical syndrome in endurance runners, and can range in severity. risk factors for eamc have been identified and include age, gender, racing distance, a history of chronic diseases, medication, training and competition load, and running injuries. however, to date, risk factors for more severe eamc (recurrent cramping) have not been investigated. the purpose of the study was to document risk factors associated with eamc in distance runners, including more severe eamc. methods: data analysis from a 2-year prospective cohort study in 41 698 distance runners (21km and 56km) who completed an online pre-race medical screening questionnaire. independent risk factors associated with eamc (model 1: binary outcome), and risk factors associated with severe eamc (defined as recurrent cramping history > 10 times)(model 2). results: significant risk factors (p 40yrs, increased bmi, history of any git or kidney/bladder disease; chronic or regular medication use, history of a running injury in the last 12 months, running in the 56km race, running 5yrs, training 6min/km). in model 2, severe eamc was associated with all the risk factors for eamc in model 1, but also included a history of any cardiovascular disease (cvd) symptoms. in model 2, a lower bmi and running in the 21km race were also specific risk factors for severe eamc. conclusion: risk factors for the clinical syndrome of eamc in distance runners are identified, including novel risk factors associated with more severe eamc (a history of cvd symptoms, lower bmi and shorter race distance). physicians need to consider secondary causes (including underlying chronic diseases) in the diagnosis and prevention of eamc, and also consider different risk factor for recurrent (severe) eamc in endurance athletes. o36: injuries and illness in athletes with spinal cord injury: lessons from london 2012 summer paralympics tommie swart1, prof wayne derman2, dr yunna albertus-kajee1, esme jordaan3 1university of cape town, 2isem university of stellenbosch, 3biostatistics unit, south african medical research council presenting author e-mail address: tswart@intekom.co.za background: despite significant growth in the paralympic sport, limited research exists describing injury and illness in paralympic athletes. of all athletes with impairment, athletes with sci constitute a unique group. not only do they have physical restrictions due to loss of movement, but also have sensory and autonomic deficits that challenge their health and well-being. objective: the main objective of this study was to determine the incidence and nature of illnesses and injuries in a cohort of athletes with spinal cord injury (sci) during the 3-day pre-competition and 11-day competition period at the 2012 london summer paralympic games. methods: this study is a component of the large prospective cohort study conducted over the 14-day period of the london 2012 summer paralympic games, coordinated by the medical committee of the international paralympic committee (ipc. a total of 3009 athletes, of which 709 were athletes with sci formed part of this study. the incidence rate (ir) for illnesses and injuries in athletes with sci was calculated as the number of illnesses and injuries per 1000 athlete days and was compared to a group of all other paralympic athletes with injury and illness (who had other impairments). results and discussion: athletes with sci injury have a higher rate of upper limb injuries (ir 6.4 injuries/ 1000 athlete days vs 4.4 injuries/1000 athlete days) and a lower incidence of lower limb injuries than other paralympic athletes (ir 1.4 injuries/ 1000 athlete days vs 4.2 injuries/ 1000 athlete days). total-, skinand genito-urinary illnesses were also significantly higher in athletes with sci compared to all the other athlete impairment groups (ir 15.4, 3.9, 2.3 illnesses/ 1000 athlete days vs 11.0, 1.8 and 0.5 illnesses/ 1000 athlete days respectively). the results of this study suggest that greater attention should be given to the prevention of upper limb injuries and skinand genito-urinary illnesses in this group of athletes. efficacy of prevention programmes should be assessed in the future. o37: cerebral haemodynamics and cognitive performance in stroke survivors following exercise elmarie terblanche1, dr bradley james fryer1 1stellenbosch university presenting author e-mail address: et2@sun.ac.za purpose: while there is evidence of differences in cerebral haemodynamics and cognitive performance between stroke patients and both elderly and young healthy individuals, no research have examined changes in cerebral haemodynamics and cognitive performance during exercise in stroke patients. this study aimed to determine whether light intensity exercise has similar effects on the cerebral oxygenation and cognitive task performance of stroke patients and healthy age-matched individuals. methods: thirty two men and women (52 to 85 years), of which 14 were stroke patients and 18 were healthy age-matched controls, volunteered for this study. the post-event period for the stroke patients was 14.8 + 6 months and 11 of the 14 patients had left hemisphere damage. each participant was required to attend one testing session where measurements of cerebral haemodynamics were obtained via near-infrared spectroscopy (nirs). nirs monitoring was done at rest, while the participant performed the modified stroop task and during a six minute walk test (6mwt). cohen’s effect sizes (d) were calculated to compare the magnitude of difference between groups. results: a decrease in o2hb levels was observed after exercise in the experimental group during both the simple and complex tasks (-15.4 + 0.6 vs -8.33 + 0.5μmol), while the control group had higher oxygenation levels during both tasks (2.78 + 0.3 vs 16.7 + 0.5μmol). practically significant lower o2hb values were observed in the left prefrontal cortex of the stroke patients compared with the controls (es = 0.4). after exercise, reaction (rt) on the simple cognitive task improved in both groups from resting levels (1.37 + 0.2s vs 0.96 + 0.1s; es = 0.4), while performance was worse on the complex task in stroke patients, but not controls (-0.81 + 0.1s vs 1.27 + 0.2s; es = 0.6). conclusions: cerebral oxygenation was dependent on the complexity of the cognitive task and was blunted in stroke patients. while light exercise had a positive effect on cognitive task performance in both groups, it had a negative effect on the stroke patients during the complex task; this finding may suggest neural fatigue because of a delayed haemodynamic response or a reduction in regional cerebral blood flow. mailto:sonja.swanevelder@mrc.ac.za mailto:tswart@intekom.co.za mailto:et2@sun.ac.za o38: plantar foot loading patterns of healthy weight and overweight school children from south africa and germany gabriella tidbury1, dr karsten hollander2, prof dr astrid zech3, prof dr ranel venter1 1department of sport science, stellenbosch university, stellenbosch, south africa, 2department of sports and exercise medicine, institute of human movement science, university of hamburg, 3department of sport science, friedrich schiller university jena, jena, germany presenting author e-mail address: gabrielatidbury@gmail.com excessive plantar loading (peak pressures) can possibly cause deterioration of the soft tissue such as the soft tissue such as the fat pads in the foot during locomotion (mickle, steele & munro, 2006). it is speculated that foot pain experienced by overweight individual’s results from the higher mechanical loading of their feet because of the additional body weight they carry (butterworth et al., 2015). the study investigated the plantar loading differences between the healthy weight and overweight children aged 10 to 13 years from south africa and germany. plantar loading measurements were obtained from 178 children (mean age 12.3 ± 1.2 years; body weight 49.2 ± 12.2kg; height 1.56 ± 0.01m; n = 178 of which 87 were girls and 91 boys) from south africa and 139 children (mean age 12.3 ± 0.1 years; body weight 47.3 ± 1.0kg; height 1.55 ± 0.01m; n = 139 of which 61 were girls and 78 boys) from germany with the emed n50 pressure platform using the two-step method at a self-selected walking speed. peak pressure, pressure-time integral, force-time integral and contact area variables were investigated for nine regions of the foot. children were categorised into a heathy weight category or overweight category according to their body mass index (bmi) (cole & lobstein, 2012). a mixed model linear regression was used to analyse the data. the overweight children from south africa had statistically significantly higher peak pressure, pressure-time integral, force-time integral and contact area for most of the foot regions than the healthy weight children from south africa. german children had significantly higher peak pressure, pressure-time integral and force-time integral values than the south african children of the same weight category. the healthy weight south african children had significantly greater contact area for most regions of the foot compared to the healthy weight german children. body weight is a primary factor influencing plantar loading values. it is possible that the significant differences found in midfoot region iii of the overweight children compared to healthy weight children could have been influenced by structural foot differences. plantar loading differences between the german and south african children could be a result of structural foot differences. o39: sa case studies: the effect of an exercise intervention program on the cardio-metabolic profiles of a diabetic; a metabolic syndrome; a cardiovascular and a depressive patient georgia torres1 2 1activate health, 2university of wits (honorary lecturer) presenting author e-mail address: georgie@pentanet.co.za exercise intervention programs are an effective treatment for patients with non-communicable diseases (ncd) of lifestyle. the activate health exercise intervention program is a specific 12 week exercise methodology, delivered by health care providers and using cloud technology to deliver health outcomes to ncd. the changes in cardiorespiratory fitness; muscle strength; weight; blood pressure; waist circumference; cardiovascular risk factors; blood lipids; blood glucose and the hamilton rating score will be presented in each of the disease cases. the positive health outcomes will be discussed. o40: prevalence and etiology of injuries in trail runners johan van heerden1, callyn poole1, megan steyn1, devan de costa1 1biokinetics, exercise and leisure science, university of kwa zulu-natal presenting author e-mail address: vanheerdenj@ukzn.ac.za introduction: trail running is a fairly novel sport and although the literature is not definitive, it can be said that the sport was born when the world mountain running association was established in 1984. in 1995, the british athletic federation approved a formal definition for trail running events. since then the sport has taken off and become well known across the globe, however, there is very little research or literature regarding it. aim: this study aimed to determine the prevalence and potential etiological causes of injuries in trial running as an injury prevention initiative. methods: an epidemiological survey was undertaken among a group (n=50) of runners participating in trail running events over a 4 month period, probing their injury history over a retrospective period of 12 months. results: fifty seven percent (57%) of participants reported an injury in the previous 12 months. injuries were incurred at the ankle (35%), knee (30%) and calf (20%). the majority of injuries took place on rough trail surface (62.5%; p0.0001) vs rocky terrain (12.5%) or cement, muddy or grassland surface (8.3%). significantly more injuries took place on down-hill slopes (57.1%; p0.05) vs level ground (33%) and up-hill (9.5%). in 80% of injuries trail running shoes were worn (p40km (20%). a significant odds ratio for injury were found for genu varus or = 2.0 (95% ci 0.1920.3) and pronation or=2.3 (95% ci 0.4-10.6) while a significant protective odds ratio was found for a neutral foot and non-injury or = 0.32 (95% ci 0.06-1.5). discussion/ conclusion: trial running does expose participants to a fairly high risk of injury, with the lower limbs mostly involved. specific ranges of training mileage were not linked to injury. the rough surfaces did pose a risk, particularly down-slopes and trail shoes do not necessarily protect against injury. the presence of bowed legs and flat feet are significant risks for injury while a neutral foot appears to protect against injury. o41: differences in foot posture between habitually barefoot and shod children and adolescents ranel venter1, elizabeth mathewson1, astrid zech3, johanna elsabe de villiers1 2, karsten hollander2 1department of sport science, stellenbosch university, stellenbosch, south africa, 2department of sports and exercise medicine, institute of human movement science, university of hamburg, germany, 3 department of sport science, friedrich schiller university jena, germany presenting author e-mail address: rev@sun.ac.za during locomotion, the foot needs to be pliable for shock absorption, but also act as a rigid lever during push-off (onodera, et al., 2008). altered foot function can lead to muscle imbalances, balance problems or gait abnormalities, as well as decreased efficiency and effectiveness of the foot (wegener et al., 2015). the growing feet of children are sensitive to external forces as the ligaments, muscles and bone s are still in the process of maturing. differences in foot morphology between habitually and barefoot individuals have been reported (hollander et al., 2017). mailto:gabrielatidbury@gmail.com mailto:georgie@pentanet.co.za mailto:vanheerdenj@ukzn.ac.za mailto:rev@sun.ac.za plantar pressure measurements can provide critical information on foot structure, foot function and general gait mechanics (keijsers et al., 2009). the purpose of the study was to compare habitually barefoot (south african) and shod (germany) children and adolescents in terms of foot posture and selected plantar pressure parameters. in a cross-sectional observational study with stratified sampling, 437 south african (boys: 228; girls: 209) and 214 german (boys: 96; girls: 118) children and adolescents between the ages of six to eighteen years old participated in the study. testing equipment utilised included a manufactured foot calliper, as well as an emed-n-50 (hamburg, germany) pressure plate. a barefoot scale was used to quantify the footwear habits of participants. concerning contact area of the foot regions relative to total foot contact area, south african children had greater weight bearing on the medial side of the foot, as well as greater pliability of the foot, compared to the german children. the coefficient of spreading indicated that south african children have broader feet relative to foot length compared to the german counter parts. wearing restrictive footwear could lead to decreased pliability of the foot and a narrower forefoot, which might affect plantar pressure distribution during gait. o42: vitamin d status amongst elite rugby union players – an observational pilot study jeandré viljoen1 2, dr glen hagemann3, dr alan kourie3, danielle roberts3 1institute of sport and exercise medicine, stellenbosch university; 2ioc research centre, south africa, 3sharks medical presenting author e-mail address: jtviljoen@sun.ac.za background: poor vitamin d status has far-reaching repercussions for health, well-being and human performance. deficiencies are common amongst the general population, however, little is known about the status of this nutrient within athletes. the purpose of this pilot study was to determine whether vitamin d deficiency exists amongst elite south african rugby players and to ascertain if factors including seasonal climatic variation, dietary intake and skin type play a role in the clinical presentation thereof. methods: a cohort of elite rugby union players underwent a medical assessment to determine factors related to vitamin d status. this included i) collection of a blood sample to measure serum 25-hydroxyvitamin d [25(oh) d] concentration, ii) completion of a 3-day dietary recall and iii) a fitzpatrick skin type classification questionnaire (evaluating genetic predisposition, reaction to sun exposure and tanning habits). an initial assessment of 41 players was performed during the summer months and a follow-up of 17 athletes during the winter period. these opposing seasons served as an indirect measure of absolute sunlight exposure. results: the mean s[25 (oh) d] at the beginning of the study was 59.98ng/ml-1, while the mean s[25 (oh) d] at time point 2 was 36.98ng/ml1. analysis of paired data revealed that 88% (2/17) of individuals displayed adequate s-[25 (oh) d] during summer with the remaining 12% (2/17) of cases showing signs of insufficiency. during winter, 82% (14/17) had adequate s[25 (oh) d] while 6% (1/17) and 12% (2/17) of players displayed concentrations indicative of insufficiency and deficiency. no relationship was found between reported dietary intake and s[25 (oh) d]. however, a negative correlation (p=0.05) was found for summer s[25 (oh) d] and the fitzpatrick skin type score (i.e. players with darker skin types, had a lower s[25 (oh) d]. conclusions: vitamin d deficiency was relatively uncommon amongst this group of athletes. however, seasonal differences and differences in skin score were noted pertaining to s[vitamin d]. this effect is likely due to changes in the length of sunlight exposure associated with normal seasonal climatic variation and endogenous vitamin d production. o43: feasibility of higher intensity goal oriented gait re-training in chronic stroke patients: a pilot study. jeanine watson1, dr. karen welman1, dr. bernhard sehm2 1stellenbosch university, 2max planck institute for human cognitive and brain sciences; university leipzig presenting author e-mail address: 16043952@sun.ac.za background: independent gait is a major goal in stroke rehabilitation. goal-oriented training has yielded the most beneficial results in the recovery of gait and recently higher intensity training was reported as feasible. further, it is known that gait ability and cognitive function are associated. thus, this study aimed to assess the feasibility of moderate-to-high intensity and goal oriented gait re-training program in chronic stroke patients. secondary, the association between gait ability and cognitive function was assessed. methods: in this pilot, a case controlled trial was implemented. participants (n=3) completed 8 weeks of moderate-to-high intensity goal oriented gait re-training that included both treadmill and overground training. participants trained three times per week for 45 minutes. results: clinically significant changes were found in the 6-minute walk test (854.47m ±120.79m) and global cognitive function (p=5±1). conclusions: chronic stroke patients may benefit moderate-to-high intensity goal-oriented gait re-training both in mobility and improved cognitive function. o44: somatosensory training improves sensory integration but not haptic feedback in individuals with mild to moderate parkinson’s disease karen estelle welman1, tania zastron1 1stellenbosch university presenting author e-mail address: welman@sun.ac.za introduction: postural control is a complex perceptual-motor process that allows an individual to maintain balance through feedback and feedforward mechanisms from visual, vestibular and the somatosensory systems (brown et al., 2006). however, proprioceptive integration and the ability to interpret haptic feedback are reported to be impaired in individuals with parkinson’s disease (jacobs et al., 2006; salgado et al., 2013). researchers investigated whether light haptic feedback would influence postural sway and if eight-weeks of somatosensory training can alter the haptic feedback influence on postural sway in individuals with parkinson’s disease. methods: thirty-seven individuals with idiopathic parkinson’s disease (age: 67 ± 9.03 years; hoehn&yahr: 2.12 ± 0.67; mds-updrs part iii: 28 ± 14) were divided into two groups i.e. a somatosensory training group (exp; n = 24) and a placebo group (pbo; n = 13). the intervention consisted of an eight-week somatosensory training program, emphasising balance exercises, performed three times per week, each progressively increasing in complexity and difficulty. postural sway was assessed with the instrumented sway tri-axial accelerometer to assess root mean square during 4 sensory conditions i.e. eyes closed with no manual contact, eyes closed with light haptic feedback, both on a stable surface and on a foam pad. secondary outcome measures were balance confidence and motor experiences of daily living. all assessments were done at baseline, before and after the intervention. mailto:jtviljoen@sun.ac.za mailto:16043952@sun.ac.za mailto:welman@sun.ac.za results: both groups presented with reduced postural sway amplitude when receiving haptic feedback compared to no manual contact, regardless of the surface area (p 0.01). exp group improved sensory integration (p = 0.01) and showed a tendency for improved balance confidence (p = 0.07) and motor experiences of daily living (p = 0.05) at post-intervention. conclusion: light haptic feedback improves postural sway in individuals with parkinson’s disease, regardless of the surface area. however, somatosensory balance training did not alter the influence of haptic feedback, but it holds the potential to improve sensory integration, balance confidence and motor experiences of daily living in individuals with parkinson’s disease. o45: lifetime prevalence, annual incidence, and incidence of common running injuries differ between 21.1km versus 56km runners: a cross sectional study in 76 654 distance runners paola wood1, martin schwellnus 2 3 4, sonja swanevelder5, esme jordaan5 6 1sport, exercise medicine and lifestyle institute (semli) and division of biokinetics & sports science, department of physiology, faculty of health sciences, university of pretoria, south africa, 2sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, south africa; 3international olympic committee (ioc) research centre, south africa, 4emeritus professor, faculty of health sciences, university of cape town, south africa, 5biostatistics unit, south african medical research council, 6 statistics and population studies department, university of the western cape presenting author e-mail address: paola.wood@up.ac.za introduction: long-distance running is very popular, but is associated with non-traumatic (overuse) injuries (nti). there are little data on the differences in ntis between 21.1km vs. ultra-marathon (56km) runners. the aim of the study was to compare the lifetime prevalence, annual incidence and types of common ntis in 21.1 km and 56km runners. methods: 76 654 consenting participants in the two oceans marathon races (21.1km=47 069; 56km=29 585) were studied (2012-2015). nontraumatic (overuse) injuries (nti) were self-reported as part of an online pre-race medical screening and intervention system administered during the race entry process. crude (un-adjusted for age, sex) lifetime prevalence, annual incidence, and annual incidence of common running ntis (% runners; 95% ci) were compared in 21.1km and 56km runners. results: the lifetime prevalence of nti in all runners was 16.8% (16.6-17.1)(12 884 injured runners), and this was higher in 56km (22.3%; 21.922.8)(6 608 injured runners) than 21.1km (13.3%; 13.0-13.6)(6 276 injured runners) runners. in all runners reporting lifetime ntis, the annual incidence of nti in the previous 12 months was 64.7% (63.8-65.5), and this was higher in 21.1km (70.7%; 69.6-71.8) vs. 56km (58.9%; 57.7-60.1) runners. in runners reporting nti in the previous 12 months, the annual incidence of typical running injuries differed significantly between 21.1km vs. 56km runners as follows: patellofemoral pain (21.1km=5.0%; 4.4-5.6: 56km=3.7%; 3.1-4.3), itb (21.1km=19.0%; 17.9-20.2: 56km=16.2%; 15.0-17.3), achilles tendon injury (21.1km=7.6%; 6.8-8.3: 56km=9.7%; 8.8-10.7), hamstring injury (21.1km=5.1%; 4.4-5.7: 56km=8.8; 7.9-9.7) and calf muscle injury (21.1km=6.6%; 5.9-7.4: 56km=10.8%; 9.8-11.7). conclusion: 21.1km runners report a lower lifetime prevalence of nti but a higher annual (12 months) incidence of nti vs. 56km runners. the annual incidence of patellofemoral pain and itb is higher in 21.1km vs. 56km runners, but 56km runners report higher incidence of achilles tendon, and muscle (calf, hamstring) injuries. risk factors for running injuries in these race distances needs to be determined to develop appropriate prevention strategies. case studies ccp1: an unusual muscle tear in a cricket fast bowler emmari carstens1 2 1institute of sport and exercise medicine, stellenbosch university, 2department of physiotherapy, stellenbosch university presenting author e-mail address: emmycarstens@sun.ac.za history: a 21-year-old collegiate cricket fast bowler was referred to the physiotherapy clinic by a sports physician after presenting with left sided proximal shin pain which had been aggravated during two consecutive training sessionsone involving bouts of sprinting on a grass surface and the other bowling in the cricket nets. physical examination: • no visible signs of swelling, discolouration or bruising were present. • palpation of the left tibialis anterior muscle revealed moderate tenderness proximally • walking was painful • isometric muscle testing of left tibialis anterior muscle proved painful • passive stretching of the left tibialis anterior muscle elicited pain differential diagnosis: 1. acute tibial stress fracture 2. medial periostitis 3. tibialis anterior muscle tear test & results: a diagnostic musculoskeletal ultrasound scan was performed confirming a working diagnosis of a grade 2 proximal tear of the left tibialis anterior muscle. final / working diagnosis: a proximal tibialis anterior muscle tear in the left lower leg (grade 2). treatment and outcomes: 1. initial management consisted out of rest and physiotherapy soft tissue treatment, dry needling, eccentric muscle rehabilitation exercises and balance and proprioception training. 2. six weeks post-injury the patient was still symptomatic, despite visible healing of the muscle tear upon musculoskeletal ultrasound. 3. referral to a biokineticist occurred at 6 weeks at which stage rehabilitation exercises were progressed. 4. the athlete had full pain free range of motion after 10 weeks and commenced with running as well as a graded return to training and sport. mailto:paola.wood@up.ac.za mailto:emmycarstens@sun.ac.za ccp2: management of difficult dislocation ali ganai1 1isem presenting author e-mail address: aliganai@yahoo.co.in reduction of important dislocations: important to know the different types of dislocation of joints with how to reduce them nicely and accurately with new techniques which are incorporated in management with respect to sports medicine especially. like, in different games, like rugby or football and other athletes , shoulder dislocations can be reduce with one person technique and elbow dislocation can also be reduce with one person technique which will be quick and easy to be done. to know the reduction techniques are important for sports physician because to maintain the accuracy and increased success rates for early healing and quick return to play plan. although, during reduction, fracture can occur as complications but with new techniques, risk can be reduce for fractures with closed reduction of joints with evaluation of neurovascular system. patients would be followed in orthopedics clinic and would have been plan further to protect the future dislocations to be happen which is very important for players in sports medicine. there are different methods to reduce different joints with techniques which are helpful in managing the patient which may include reductions under conscious sedation to under general anesthesia which depends on the complications like fracture with dislocations. ccp3: longstanding bilateral hip pain in a field hockey player tanya green1 2 1 institute of sport and exercise medicine, stellenbosch university, 2department of physiotherapy, stellenbosch university presenting author e-mail address: tanyagreen@sun.ac.za history: a 19-year-old collegiate field hockey player was referred to a physiotherapy clinic by a sports physician after presenting with a history of longstanding recurrent bilateral groin pain. prior rehabilitation efforts (during the previous season) had failed and the athlete’s condition had deteriorated to the point that all training had ceased and pain was experienced with walking. the option was given to the athlete to undergo further conservative treatment or instead to be referred to an orthopaedic surgeon for further management. again, the decision was made to first pursue a conservative course of action. physical examination: • gait assessment revealed a slight limp with a shift in body weight towards the right side. • single leg stance assessment revealed inferior displacement of the left posterior superior iliac spine indicating a weak gluteus medius muscle. • limited rom during hip flexion; pain experienced upon internal rotation and external rotation (especially with hip at 90° flexion) • + adductor squeeze test • + faber • + fadir • bilateral lumbo-pelvic stiffness was evident together with associated muscle tightness in the hip flexors/gluteals/quadratus lumborum and piriformis muscles. differential diagnosis: 1. labral tears of the hip with associated core instability 2. adductor tendinopathy with pubic symphysitis 3. hip impingement test & results: plain radiographs of the pelvis and both hips were requested which confirmed a working diagnosis of bilateral femoro-acetabular impingement (asymmetric r>l) with small acetabular accessory ossicles final/working diagnosis: bilateral femoro-acetabular impingement (asymmetric r>l) with small acetabular accessory ossicles. treatment and outcomes: 1. initial physiotherapy management consisted of soft tissue treatment (myofascial release / stretches and foam rolling) together with a home – based rehabilitation program. 2. failure to respond to conservative management after 4 weeks resulted in the athlete being referred back to the sports physician. 3. subsequent referral to an orthopaedic surgeon with bilateral hip arthroscopy procedures to remove the accessory ossicles. 4. the athlete is recovering well and currently still undergoing post-operative rehabilitation (week 5). ccp4: lumbar stress injury or not? – a case study of a cricket player dina christina janse van rensburg1, phathokuhle c zondi1, audrey jansen van rensburg1, catharina cornelia grant1 1university of pretoria presenting author e-mail address: christa.jansevanrensburg@up.ac.za case history: a 18 year old male cricket player (fast bowler) presented with longstanding symptoms of stiff calves and hamstrings, and pain in the gluteal and lower back regions. he had been treated conservatively for a lumbar stress injury (including a full rehabilitation program) however his symptoms persisted. on further enquiry he had previous problems with his left achilles tendon and a right-sided tennis elbow. although his back pain was slightly relieved during warm up he did not respond to non-steroidal anti-inflammatory drugs. no further systemic complaints were elicited. he has a family history of an uncle diagnosed with reiter’s syndrome. physical examination: he had slight tenderness of the lower lumbar area to the left of the spinous process. neurological examination was normal. the schöber test and chest expansion were normal. the faber test was positive on the right and left, and the sacroiliac joints were tender on palpation. differential diagnosis: 1. lumbar spondylolysis 2. ankylosing spondylitis 3. vertebral disc lesion test and results: blood tests erythrocyte sedimentation rate: normal mailto:aliganai@yahoo.co.in mailto:tanyagreen@sun.ac.za mailto:christa.jansevanrensburg@up.ac.za c-reactive protein: normal human leukocyte antigen b27: positive x-rays lumbar: no spondylolysis or spondylolisthesis. slight narrowing noted of the l4/l5 intervertebral disc space. no vertebral body margin osteophytes or end plate changes identified. pelvis: normal mri sclerosis of the lower lumbar facets, left (l4/l5 and l5/s1). thought to be due to overuse. slightly narrowed l4/l5 disc space, but no herniation or prolapse. reactive changes of the right sacroiliac joint, but no bony edema. treatment and outcome: 1. because of the clinical picture, inconclusive radiography and positive hla b27, the athlete was treated for inflammatory arthritis. he was prescribed a course of prednisone to which he responded dramatically well. 2. following the significant improvement, a decision was made to treat for ankylosing spondylitis and include a stringent rehabilitation program for the other problems identified. 3. the athlete responded well, and after xxx weeks returned to full training. final diagnosis: ankylosing spondylitis complicated by overuse of the lumbar facets possibly due to his sport. ccp5: complicated synovial cyst tibiofibular joint squash – a case study dina christina janse van rensburg1, dimakatso a. ramagole1 1university of pretoria presenting author e-mail address: christa.jansevanrensburg@up.ac.za case history: a 47year old male veteran squash player presented with intermittent left knee pain and swelling below the knee joint. he also complained of back pain and reduced sensation in his left foot. he had no history of trauma and has been treated for gout for 5 months prior to consultation. physical examination: he had tenderness on his medial joint line and 3 separate masses on the lateral aspect of his lower leg. the masses were soft, compressible and not tender to the touch. he also had reduced sensation in the l5 distribution, but no weakness of ankle dorsiflexion, toe extension or ankle eversion. differential diagnosis: 1. space occupying lesion (benign, malignant) 2. nodule (gout, rheumatoid arthritis) 3. common peroneal nerve involvement vs l5 radiculopathy test and results: blood investigations: uric acid 0.33 mmol/l (previously elevated at 0.59 mmol/l). rheumatoid factor was negative. anticitrullinated protein antibodies was negative. imaging: ultrasound lower leg: anterior proximal in the left lower leg a cyst of 44.5 x 19.9 mm. a second synovial cyst of 59.8 x 26 mm and a third synovial cyst measuring 17.5 x 5.4 mm were also visualised. all cysts were connected with small tracts. xrays of the knee: narrowed medial tibiofemoral joint space. erosions of the tibiofibular (tf) joint. xrays lumbar: l4s1 disc spaces narrowed. grade 1 degenerative anterolisthesis of l4 in relation to l5. mri lower leg: cysts not in relation to peroneal nerve, well circumscribed, homogenous content with pressure effect on muscles. intraosseus cysts tf joint. mri lumbar: confirmed listhesis identified on xray. paravertebral joint osteoarthritis (oa) l4,5 with degenerative cyst lateral resess of l5 and pressure effect on left l5 root. final working diagnosis: 1. multilocular synovial cyst tf joint ± peroneal nerve involvement 2. gout 3. l5 facet joint oa with nerve root radiculopathy treatment and outcomes: this was the patient’s first consultation. keeping the possible double pathology in mind (i.e. l5 root pressure and/or peroneal nerve involvement) an emg will shed more light on future treatment. surgical excision of the cyst will probably be needed. in the meantime gout treatment was continued. conservative management and reassessment of the lumbar pathology were advised. ccp6: acute, non-traumatic muscle tear in a provincial rugby player, all is not what it seems to be gershwin kortje1, wayne derman1 1institute of sport & exercise medicine, stellenbosch university, south africa presenting author e-mail address: gershwinkortje@gmail.com history: a thirty (30) year old male rugby player, presented during a league rugby match with an acutely painful and swollen left thigh. he denied any history of contusion or extensive knee flexion happening during the game. physical examination: the patient was unable to continue playing. further assessment revealed severe tenderness over the midthigh associated with tense swelling and a reddish/purple discoloration. the athlete was an apparently healthy male, no other symptoms, no previous significant medical/ surgical history, no chronic medicine/ drug/ alcohol abuse and no allergies of note. one hour after injury, the athlete was unable to flex the knee at all. two hours post-injury, his peripheral pulses subjectively became weaker, while affected thigh pain became worse. differential diagnosis: 1) quadriceps muscle tear / quadriceps tendon tear with large haematoma. developing compartment syndrome. special investigations; an in office, musculoskeletal ultrasound revealed a tear of the recus femoris muscle with accompanying large haematoma. the patient was transferral to grootte shuur hospital (gsh) for further management +/fasciotomy. further work up included a ct scan which confirmed soft tissue swelling and haematoma. crp & esr = above normal limits; white cell count 90 000 cells/l, decreased hb (8.0g), increased basophils, increased plt’s, (normocytic, normochromic anemia), myeloblast > 10%. a pcr was performed & revealed positive bcr-abl oncogene highly suggestive of cml. final diagnosis: cml(chronic myelogenous leukemia) with muscle rupture & haematoma. management: gleevec (imatinio mesylate) chemotherapeutic reigime with 3 monthly follow-up. no return to play in contact sports for 12 months. he returned to play january 2017 (12months post injury/ diagnosis) – first game back he injured his right knee and was unfit for play for another six weeks. played five games (with intermitted muscle cramps and pain/aches), injured his right side of rib-cage and has not played since. mailto:christa.jansevanrensburg@up.ac.za mailto:gershwinkortje@gmail.com ccp7: not all acute footbal groin injuries are groin disruptions a multi-system extra pulmonary tb masquerades as an acute sports injury mamosilo lichaba presenting author e-mail address: mamosilo.lichaba@wits.ac.za mycobacterium tuberculosis (tb) is an ancient disease seen in early humans, but remains amongst the top 10 causes of death globally, and the leading cause of death due to infection. sub-saharan africa is the worst affected, with south africa ranking 6th in the world the hiv epidemic worsens the picture. it is imperative for clinicians to be aware of tb, extra-pulmonary tb (eptb) and the multivariate ways in which eptb can present. eptb can mimic many multisystem illnesses and is difficult to diagnose. all doctors working in south africa have to be vigilant with a very high index of suspicion for eptb, in atypical patient presentations in our case, a patient who is known to be hiv positive on haart, sustained a football groin injury and presented with a clinical severity out of proportion to the clinical and radiological pathology. he subsequently turned out to have musculoskeletal and genito urinary tb. key words: human immunodeficiency virus/acquired immune-deficiency syndrome (hiv/aids); mycobacterium tuberculosis (tb); extrapulmonary tb (eptb); highly active antiretroviral therapy (haart); hiv-tb co-infection; spine tb; multisystem tb; groin injury ccp8: to catch a red herring? : knee pain in a healthy male ultra-marathon runner riaan van tonder1, dr. pierre viviers1, prof. wayne derman1 1institute of sport and exercise medicine (isem) presenting author e-mail address: riaan.vt@mweb.co.za a 58-year-old healthy male ultra-marathoner presented with a 3-month history of atraumatic, gradually worsening right-sided knee pain, aggravated by activity and associated with prominent morning stiffness and pain. night pain was absent. oral and parenteral nsaids provided no relief, nor did massaging. no history of smoking, alcohol or prior corticosteroid use was reported. examination revealed a slightly swollen right knee, with associated tenderness on palpation over the quadriceps tendon insertion and superomedial knee, without an effusion. in addition, the patient showed significant weakness of the right gluteus medius and quadriceps muscles. tests for mechanical disruption and injury were negative. a differential diagnosis of quadriceps tendinopathy and possible patellar-femoral pain was made and conservative management, consisting of physiotherapy and an eccentric strengthening program, advised. x-ray of the r knee revealed a hypo-lucent area in the distal femur (just proximal to the condyles). mri of the knees bilaterally revealed areas of increased signal in the distal femoral shaft highly suggestive of bilateral bony infarcts. blood tests including fbc and crp were normal conclusion: spontaneous osteonecrosis of the knee (sponk), or ahlback’s disease, described initially in 1968, is rare, idiopathic cause of knee pain, usually unilateral, and commonly affects females more often than males in their fifties and sixties. whilst it is tempting to attribute the cause of this athlete’s knee pain to this condition, the pain was unilateral and improved with rehabilitative exercise. this case should alert the clinician to be mindful of rare and unusual causes of knee pain in the athlete and the impact of chosen form of exercise thereon. it is still debated whether this athlete should return to full participation in ultra-marathon running. posters p1: sudancupping test for radiating pain in sport injuries, a new tool for a challenging diagnosis samahir abuaraki 1, samahir abuaraki elbkeet1, ahmed babiker elhag2, tarig abdulla abdulmajid1 1sport physiotherapy, sport medicine2 presenting author e-mail address: samahir49@gmail.com introduction and purpose: sports injuries refer to the kinds of injury that occur during sports or exercise. it is commonly used to refer to injuries of the musculoskeletal system. they are usually present with onset of sudden and severe pain. it is constant symptom in sport injuries. usually it forces the player to seek medical help. radiating pain is a pain that results from injury or disease of neurons in the peripheral or central nervous system. its character is often burning or electrical, and it can be persistent or occur in short episodes. this is usually because of nerve or plexus damage. sudan-cupping test is a newly applied and newly registered dry cupping test, based on the use of different sized cups for cupping o ver certain areas of the spine. the test can detect the radiating pain to the joints (knee, ankle or shoulder) and muscles. the use of cupping therapy as a diagnostic tool is not mentioned in the literature. this study (to our knowledge) is the first study to look into use of dry cupping as a diagnostic tool in sport injuries and regular dry cupping sessions as therapeutic tool as well. methods: the study includes 522 professional football players between the age of 18 -28 years for the period 2013-2015. they play on regular regimen in the sudanese league. the players presented with different football injury pain such as ankle joint pain, knee joint pain, posterior thigh muscle group pain, anterior thigh group muscle pain, middle thigh muscle group pain and calf muscle pain. instrumental investigations such as x-ray, muscle ultrasound and magnetic resonance imaging (mri) were used to diagnose serious injuries in the joint or muscle area involved. a group of 108 player had absolutely normal investigations. they showed some neurological symptoms such as numbness, burning sensation, heaviness and others. their pain was fluctuating, one day up other down. the injury pain were as follows: 11 ankle joint pain, 20 knee joint pain, 22 posterior thigh muscle group pain, 16 anterior thigh group muscle pain , 28 middle thigh muscle group pain and 11 calf muscle pain .sudan cupping test was also conducted to test for radiating pain from the spinal column. this is a newly applied dry cupping test, based on the use of different sized cups for cupping over certain areas of the cervical, thoracic and lumbosacral spine. the cups are applied sequentially over the spinal column until the patient feels relieve of pain upon cupping a certain area, then the test is considered positive and that area is considered for therapeutic cupping. results: sudan-cupping test was positive in 44 (40.7%) of the players with symptoms of radiating pain. they showed the presence of positive neurological examination supporting the nerve roots compression. conclusions: pain is the most common reason for physician consultation in the united states.[1]2] it is a major symptom in many medical conditions, and can significantly interfere with a person's quality of life and general functioning.[3] psychological factors such as social support, hypnotic suggestion, excitement, or distraction can significantly modulate pain's intensity or unpleasantness.[4][5].pain in sport players does not always indicate sport injury in the joint or muscle area where the pain is felt. radiating pain from the spinal column should be excluded especially when the scenario does not fit. there are some cases in which during playing of sport, load over the spinal column occurs. mailto:mamosilo.lichaba@wits.ac.za mailto:riaan.vt@mweb.co.za mailto:samahir49@gmail.com this leads to sudden compression of the nerve roots at the lumbosacral area. this causes radiating pain in sport injuries. sudan-cupping test is sensitive in such cases, saves time to initiate therapy and shortens time to return to play. we recommend the sudan-cupping test to be as initial screening test in sport injuries. the test is simple, fast, cheap and easy to apply. it could be made available even in the field and during the competitions. p2: seasonal variation in vitamin d levels of south african male football referees khatija bahdur1, ricard pruna2 1university of zululand, 2medical services fc barcelona, fifa excellence centre presenting author e-mail address: bahdurk@unizulu.ac.za introduction: vitamin d can be obtained from exposure of the skin to ultraviolet rays. uvb rays can be used to enhance both cardiovascular fitness and muscular endurance. the agreed classification of 25(oh) d concentration are: 150ng/ml is toxic. peak neuromuscular performance is associated with 25(oh) d levels of 50 ng/ml. vitamin d deficiency has a marked impact on health, training, performance and injury profiles of sportspeople. symptoms of vitamin d-deficiency diseases such as rickets include generalized musculoskeletal pain, muscle weakness, resultant gait abnormalities, muscle fibre atrophy, slow peak muscle contraction, prolonged time to muscle relaxation and increased risk of musculoskeletal pain. south africa has a unique climate where referees who train outside during the day are exposed to high levels of sunlight. the aim of this study was to identify seasonal variation of vitamin d levels in elite football referees who trained outside and did not take any supplements. methods: seventeen referees underwent four vitamin d (25(oh) vitamin d) evaluations for a duration of a year, with a test being conducted during each season (i.e. spring, summer, autumn and winter). all tests were done at lancet laboratories. the values were recorded and anyone with values lower than 30 ng/ml were classified as deficient. results: there were significant differences (p 0.05) in vitamin d values in the four seasons. in every season except in summer, there were participants who were vitamin d deficient. in spring 23.53 % of the sample were deficient, in autumn 41.18% and in winter 76.47 % with 23.53 % of those classified as severely deficient. in summer, 11.76% of the sample reached peak vitamin d levels of 50ng/ml and in autumn, only 5.88% reached those levels. in winter and spring no one had these values of vitamin d. conclusion: despite sun exposure, south africans are susceptible to vitamin d deficiency which can have performance and health impacts. vitamin d levels should be monitored throughout the season and nutritional interventions, through dietary changes and supplementations, should be recommended. p3: the effect of different hydration strategies on recovery on university soccer players. khatija bahdur, moeketsi robert mohlakoana1, nicholas klaasen1, phumelele msane1 1university of zululand presenting author e-mail address: bahdurk@unizulu.ac.za introduction: soccer players are subjected to heavy training loads due to their intense fixture schedule intertwined with training which leads to players not giving their body enough time to fully recover and that tends to elicit symptoms of overtraining such as fatigue and mistakes. correct recovery strategies enable players to recover at a faster rate ensuring they go into training and matches fully fit and without showing and symptoms of overtraining as well a reduced occurrence of injuries. the aim of the study was to compare the effects of four different hydration strategies in amateur soccer players looking at the different effects of fluid intake on post-exercises recovery. methods: 36 males university soccer players (age>18) were grouped (n=8) into four different groups. all groups underwent a three session football specific training, where each group was given a different post training hydration strategy. the first session was to establish base-line values and all groups were given water on pre, during and post session. seven days later each group underwent the same football specific training session but with different post-session hydration strategies. group one were used as the control and stayed with just water, group two were given a sports drink, group three were given low fat chocolate milk and group four were given a combination of the low fat chocolate milk and sports drink. the training session was also conducted 48 hours later. physiological variables measured were (ecg /heart rate/ respiration/ heart rate variability/ body activity & co-ordination) and performance scores were recorded for all three testing days. results and conclusion: please note that this is an honours project that is currently on-going and the final results will be obtained at the end of august. p4: chronic nec pain and headache after cycling ramona beeton1 1sasma presenting author e-mail address: ramonabeeton@gmail.com case history: in march 2011, a 59 yr old male patient presented with painful neck and headache after cycling. progressively worse over the past 8 months. pain on medial and lateral side of left elbow, worse on lateral side at night, causing sensation of weakness of left arm and hypersensitivity. he stopped all exercises for 2 weeks with no improvement of symptoms. very little relief with n’saids, muscle relaxants and physiotherapy. he is a known diabetic, hypertensive, hypothyroidism and hypercholesterolaemia. he cycles 5 times a week with rowing exercises and spinning in between. examination: average built adult male, bmi=29. neck has normal range of movement with tenderness over paravertebral muscles. tender left supraspinatus muscle and medial and lateral elbow areas. equal motor function, sensation and reflexes of both arms. differential diagnosis: 1. muscle spasm in neck. 2. radiculopathy c5, c6 and 7 test results: 1. mri in march 2011 revealed c3-4 posterior disc protrusion with spinal stenosis. c5-7 broad based disc protrusion posterior with spinal stenosis and facet joint degeneration. c5-6 narrowing of bilateral neural foramina with compression of nerve roots. c6-7 left sided neural foramina narrowing. 2. nerve conduction tests revealed decreased conduction in median nerve over wrist area but not yet carpal tunnel syndrome. no sign of anterior inter-osseous syndrome. final diagnosis. 1. neck: multi-level degenerative changes of discs and facet joints with nerve involvement c5-7 more prominent left side. 2. lateral elbow pain: possibly due to “double crush” sign of median nerve entrapment in wrist but also nerve compression c5-7 left. mailto:bahdurk@unizulu.ac.za mailto:bahdurk@unizulu.ac.za mailto:ramonabeeton@gmail.com discussion: these changes cause muscle spasm in his neck with aggravation of c5-7 symptoms. thoracic thrush treatments as a treatment for muscle spasm of the back was initiated, directly after cycling. outcome: the pain in his left elbow cleared and his neck discomfort and headaches improved. he is not taking n’saids or muscle relaxin g medication. since 2011, there was no need to repeat any of these tests for aggravating symptoms. he is still cycling and completed 4 argus cycle races since then. always check for aggravating conditions. p5: lower backache in long distance running ramona beeton1 1sasma presenting author e-mail address: docs@ntelecom.co.za case history: in september 2015, an active 46 yr old female complained of lower backpain while running, starting at around 20km into the race. pain spreads into gluteal regions, down back of legs to bilateral fifth toes, later spreading to all the toes. feeling of pre ssure over ischia’s. improves after resting. physiotherapy and biokinetic treatment did not improve the condition. examination: slender built adult female, bmi=20. no sciatica. reflexes, motor function and sensation of legs normal. tender on pressure over lower vertebrae, bilateral superior sacro-ileac joint areas, bilateral piriformis muscles and ischia. no sign of hamstring injuries. differential diagnosis: muscle strain of lower back due to enthesopathy. examinations: xray of pelvis normal. xrays lumbar vertebrae: spondylosis and degenerative disc changes on l5-s1 level. bone density test reveals osteopenia of lumber vertebrae (t-score -2.2), left hip (t-score -1.3), right hip (t-score -1.7). hormonal profile test normal. final diagnosis: mechanical lower backache with enthesopathy, osteopenic lumbar pain and muscle spasm. treatment: 1. calcium increase in diet as well as supplementation. 2. platelet rich plasma infiltration into bilateral superior sacro-iliac joint spaces, bilateral implantation areas of erectus muscles on sacrum, bilateral hamstring implant areas on iskia, interspinous ligament of l5-s1. 3. stop cycling and running for 2 weeks, then rehabilitate into running again. discussion: calcium increase has reduced osteopenic pain. platelet rich plasma treatment reduced inflammation process and enthesopathy progress. she rehabilitated well and has done several half marathons since then and is still without lower backpain when running. follow up of bone density test in 2017. diet and prp treatment had superior effects above traditional pain and ant-inflammatory treatment. p6: the incidence of injuries and exposure time of professional football club players in the premier soccer league during football season theodore calligeris1 2, dr. theresa burgess2, prof. mike lambert2 1ssisa, sspc, uct2 presenting author e-mail address: theo@sspc.co.za background: data on the incidence of football injuries and exposure time of players during matches and training in the south african (sa) premier soccer league (psl) are lacking. objective: to calculate the incidence of injuries and the exposure time (practice and match) of the players of a psl team over a full season. methods. injury and training data of the players in the squad (n=32) were recorded on a daily basis by the medical support staff, according to the methods of the f-marc protocol. results: one hundred and thirty injuries were recorded in the season. the most affected body parts were the thigh (n=27, 21%) and ankle (n=27, 21%). the overall incidence was 13.4 injuries per 1 000 player-hours. the incidence during training was 6.6 injuries/1 000 player-hours and during matches 88.9 injuries/1 000 player-hours. the most frequent injury was haematoma/contusion/bruising (n=43, 33%). of the total injuries, 12% were recurrent. injury through contact with another player was high (62%). seventy-six percent of the injuries were not associated with any violation of the laws of the game. the average time off due to injury was 8 days. the total exposure time over the full season resulted in a combined average of 18 162 minutes (~303 hours). conclusion: these data differ from the data in european studies. injury and exposure data measured throughout the season have the potential to identify risks and mechanisms of injuries. this study highlights the necessity for all clubs in the psl to adopt a standardised injury monitoring programme, using standardised methodology, so that the management of professional players in sa may be improved. implications: the implications of such a study is ground breaking in the field of football medicine in south africa and africa. it has a far reaching effect in describing the football population and identifying what variables need intervention for change to occur progressing the level and standards in african football. p7: case study of a javelin thrower with medial elbow pain with median nerve involvement rob donkin1 1chirosport sa presenting author e-mail address: robdonkn@gmail.com case history: this 19 year old javelin thrower presented with shooting right medial elbow pain and tingling in the forearm after taking part in three competitions within a month. no specific throw produced the pain but the elbow pain began after the third competition. patient was initially diagnosed with medial epicondylitis but after treatment no improvement in symptoms was noted. physical examination: no obvious swelling, discoloration or deformity of the upper limb or elbow was noted. passive elbow range of motion was full and pain free. active elbow range of motion was full and pain free. elbow joint play was flexible and pain free. wrist range of motion was full and did not reproduce the patient’s symptoms. resisted elbow and wrist isometrics were not painful. upper limb reflexes, myotomes and dermatomes were normal. differential diagnosis: medial epicondylitis medial collateral ligament injury of the elbow ulnar nerve traction injury cervical radiculopathy pronator teres syndrome mailto:docs@ntelecom.co.za mailto:theo@sspc.co.za mailto:robdonkn@gmail.com tests/results: an ultrasound of the elbow was requested. on the symptomatic right arm the median nerve measured 2.1mm in anteriorposterior diameter compared to the 1.5mm on the left arm. the transverse diameter of the median nerve of both elbows was symmetrical. one of the nerve fascicles on the right median nerve was swollen. all other soft tissue of the right elbow was within normal limits. final diagnosis/outcome: median nerve sprain at the elbow. a treatment approach using neural taping, wrist and elbow mobilisation, and rest with no throwing or gym activity for six weeks. return to activity: after six weeks the patient returned to normal training which included javelin throwing, cardiovascular fitness training and strength training without re-occurrence of the symptoms. discussion: medial elbow pain may be common in athletes in sports that involve throwing such as javelin. while a ligament, tendon or muscular injury may be suspected, the clinician should be on the lookout for nerve injury especially when symptoms that characterise nerve pain are present. p8: the insightful relationship between spiritual intelligence and workplace in 21’st century olessia gorkovenko1 1honour (psy), candidate phd(ed psych). m.ed(psych), b.(psy)(hons), cert(holotropic breathing), ed. cert. dip (sport psychology), cert (sport coach), cert (wellness and family therapy), cert (private practice psychotherapy and psychology), gorkovenko dr. honour (psy), candidate phd(ed psych). m.ed(psych), b.(psy)(hons), cert(holotropic breathing), ed. cert. dip (sport psychology), cert (sport coach), cert (wellness and family therapy), cert (private practice psychotherapy and psychology), honourable fellow world council for psychotherapy worldpsych.org editorial board member the international journal of psychotherapy, counseling & psychiatry: theory, research & clinical practice ispcp-trcp.org sq/si, ai and other qs research and practice ph:+270839695531 fb: pilatelicious blog:pilatelicious google map link: pilatelicious presenting author e-mail address: ovg2008@gmail.com research on spirituality has identify the criteria to predict motivational and personality properties of individuals with their surrounding environment, based on specific characteristics of each person and to describe their workplace. towards this direction notion of the spiritual intelligence (si) was introduced (emmons,2000). this intelligence been found manifests through several capacities like the ability of the transcendent state of the consciousness: the ability to perceive life as whole; it is interlinked from personal level, to family, to organization, to country to the world and to the universe. it is the ability to organise and integrate all life pursuits forwards unified goal; it is the ability to solve full range of life problems easier and quicker; the ability to engage in various behaviours like forgiveness, express gratitude, to be humble, to display compassion, to perceive uniqueness and sacredness of everyday reality, objects, people, places, relationships, roles, global connectedness to everything, and universal connectedness. it is the flexible and adaptive use of spiritual intelligence skills to solve real-life issues, to assist people to be more relevant in understanding of the manifestations of the spirituality in workplace settings. furthermore, sanctified starvings are likely to lead to a greater integration and development of the personality. spiritual intelligence influences life satisfaction, emotional wellbeing, and promote job related commitments. the ability to vie own experience of the spiritual intelligence as sacred and significant, and the understanding of the importance of the collective consciousness functioning. when work is seen as a calling rather than a job, or as opportunity to serve bigger spiritual meaning, work related goals take on the new level, become significant and meaningful (davidson and caddel, 1994). then meaning of the work gets to be transformed, to be the calling or sacred, people more likely invest more time and energy forwards work related goals and to protect this kind of goals and interests. using this intelligence, people can view their lives with extended view and act more efficiently. today, spiritual intelligence discussed as psychological domain and in other human science areasuch as management and leadership. most of scientists believe that spiritual intelligence is the most important type of intelligence which has the power to change our life, society, history and the world. keywords: spiritual intelligence, workplace, human intelligences, workplace, improvement. 1) series of related intellectual capabilities
2) can be developed during life time
3) simplifies problem solving process and compatibility with a natural specific environment
4) enables individuals in accurate judgment and reasoning
5) represents a compound component or biological bases of mind many years after introduction of spiritual intelligence and its applications all over the world, researchers found and understood that many people with higher iq have more problem in controlling their emotions and behaviours and cooperating with the other people, while people with lower iq have possibility to achieved professional successes easier (bradbury and travis, translated by ganji, 2005). introduction: when it comes to describe the variety of the reasons why people work, it can be illustrated as in the pyramid of maslow (1960), shelter and food, clothing and transportation, socialisation and need for love, money and need for self-actualisation. for the social psychologist and the psychologists of religion previous description will not be accurate or enough. instead we need to know what social and mental factors regulate the why people going to work, solve or unsolved their work related problems, embrace their identity and maintain it. i believe that knowledge about these things can help us to create healthier, more productive work environment, can provide the psychological module for the improvement of work performance and to reduce conflicts, stress and fear, dissatisfactions or unhappiness of the work choices. believing in what you are doing and emotional feeling of happiness is paramount in achieving better workplace. workers more likely to pursue transcendent goals, foster trust, a team player, healthier atmosphere, commitment to the employer and the goals. in order to build argument for this idea and the rationale for what can be called a healthy workenvironment we need to encourage meaning aspect of the spirituality at work, which can emphasise norms, values and expectations associated with the benevolent and principled ethical climates of the learning organisation which goes beyond merely making profits. by encouraging values, norms that supports caring for each other and the organisation and for the country and for the planet a such higher-order goals often reflect the spiritual values of the contribution to the society and make employers feel that they work has higher meaning. mailto:ovg2008@gmail.com p9: novel method to decrease core temperature in hyperthermic athletes cc grant1, d.c. janse van rensburg1, a. jansen van rensburg1, p. zondi1, z. mahomed1, m. bester1, e. kramer1, n. claassen1 1section sports medicine, university of pretoria, pretoria, south africa presenting author e-mail address: rina.grant@up.ac.za background: athletes from several sporting disciplines train and compete in hot environments that do not only impair performance but also pose a potential risk to athlete health. in endurance sports, for every serious cardiac adverse event, there may be 10 serious events related to heat stroke. purpose: this study investigated a carbon based compound/cooling system which was designed for therapeutic hypothermia or temperature reduction after acute ischemic events. the aim of this study was to investigate the effect of using this method, directly after athletes exercised for a maximum period of 2 hours in a hot/humid environment, or until their core temperature reached 39°c. it was hypothesized that this method can significantly decrease the time to return to the normal baseline core temperatures. methods: fifteen un-acclimatized healthy male athletes (20.3y) were asked to perform an exercise protocol in a climatic chamber (dry-bulb temperature= 39.0°c and a natural ventilated wet bulb temperature of 28.0°c). a workload of 80 watts was achieved by means of a block stepping exercise on and off a 30.5cm stepping block (stepping rate=24 steps.min-1). during the recovery period, athletes were placed in a supine position and cooling pads were fitted on chest, back, neck and thigh area until core temperature returned to baseline. a telemetric system was used for continuous core temperature monitoring. the system included a pre-calibrated temperature sensor (radio pill) and data recorder which was inserted rectally, similar to the application of a rectal suppository. the protocol was repeated twice; once with the aid of the cooling pads and once without. results: the non-parametric wilcoxon’s signed rank test indicated a significant decrease (p=0.0023) in cooling time, indicating that the cooling aid accelerated reestablishment of the athlete’s normal core temperature with 13 minutes. conclusion: this technology may provide a new alternative to accelerate the rapid cooling of athletes that experience hyperthermia, thereby avoiding catastrophic injury and adverse cardiovascular outcomes in the collapsed endurance athlete. new sport applications to be investigated include pre-/post-exercise cooling as well as during the half time break in team sports to manage the athlete’s core temperature. p10: the adverse impact of schoolbag carriage: a systematic literature review (2007-2016) henriëtte hammill1, dr. terry ellapen1, dr. mariette swanepoel1 1physical activity sports and recreation, focus area: phasrec, school of biokinetics, recreation and sport science, faculty of health science, north-west university, potchefstroom, 2520, south africa presenting author e-mail address: 12782211@nwu.ac.za introduction: heavy schoolbag carriage has become a serious concern that precipitates musculoskeletal pain and deviant vertebral posture. the objectives of the study were to: (i) identify common anatomical sites of pain due to heavy schoolbag carriage, (ii) determine what is the maximum mass that a scholar can carry on both shoulders, as well as one shoulder before the onset of pain and/or deviant posture, (iii) different methods of carrying schoolbags and its relation to pain and deviant posture, (iv) the impact of carrying heavy schoolbags on the child’s lung capacity, (v) biomechanics of pelvic alignment when carrying heavy schoolbags, (vi) the effectiveness of back care and strengthening intervention programmes to reduce pain and deviant posture, and (vii) global research regarding schoolbag carriage on children health and well-being. methods: a systematic review of literature following the primsa guidelines from 2007 to 2016 was used. the literature review identified 589 english papers that were related schoolbag carriage, which caused pain and deviant posture among scholars. results: literature demonstrates that a schoolbag mass exceeding 10% of boys’ and 5% of girls’ body mass (bm) produces pain and abnormal posture such as kyphosis, lordosis and scoliosis that diminishes their lung capacity and cardiorespiratory function. the method of carrying schoolbags (over both shoulders versus single shoulder) changes the appendicular skeleton and axial skeletal alignment that produce deviant posture. conclusion: most prevalent anatomical sites of pain include cervical vertebrae, shoulders and lower back. the fundamental problem prevailing is the lack of agreement on the maximum percentage mass of the schoolbag load that can be carried. the educational and exercise intervention programmes has shown promise to reduce deviant posture and pain. p11: evidence of benefits of exercise and its mechanisms in inflammatory arthritis dina christina janse van rensburg1, a jansen van rensburg1, da ramagole1, cc grant1 1university of pretoria presenting author e-mail address: christa.jansevanrensburg@up.ac.za introduction: rheumatoid arthritis (ra) and ankylosing spondylitis (as) are systemic, autoimmune diseases causing severe joint inflammation, leading to joint damage and functional disability. both diseases may feature comorbidities e.g. cardiovascular disease (cvd) and hypercholesterolemia. ra is most prevalent in individuals aged ≥ 18 years, with an estimated prevalence distribution of 0.41.3% worldwide. as has an age onset of 1535 years, typically affecting 79/ 100 000, with a 3:1 male-to-female ratio. evidence of benefits of exercise, and its hypothesised mechanisms in ra and as patients were explored. methods: research literature on stage of disease, amount and type of exercise and classification levels were assessed using medline and scopus databases. results: pre-evaluation includes staging of level of function (class iiv) and assessment of disease activity and comorbidities. recommended amount and type of exercise vary depending on the site and amount of impaired joints, presence/absence of inflammation, joint stability and previous joint replacements. the fitt-pro principle (frequency, intensity, time, type and progression) is followed in exercise prescription. evidence of benefit of aerobic and resistance exercise programs shows an increase in aerobic capacity, muscle strength, self-reported functional ability, endothelial function, blood pressure, lipid profile, autonomic function and muscle mass, with a decrease in body fat percentage and trunk fat mass. inflammatory disease is characterised by increased levels of circulating tnfα that induces cachexia and lead to deterioration of muscle strength. pro-inflammatory cytokine production may also predispose patients to atherosclerosis, loss of muscle mass, and metabolic disorders (insulin resistance and dyslipidemia). exercise not only improve functional outcome, but also induces an anti-inflammatory response, specifically suppressing tnfα production and stimulating the production of anti-inflammatory cytokines (il-1ra and il-10) via muscle derived il-6. conclusions: scientific literature supports the benefit of exercise to both improve functional ability and reduce cvd mortality and other comorbidities. mechanisms of the effect of exercise are on functional and anti-inflammatory level. mailto:rina.grant@up.ac.za mailto:12782211@nwu.ac.za mailto:christa.jansevanrensburg@up.ac.za p12: selected fitness values of male and female junior provincial swimmers leon lategan1 1university of johannesburg presenting author e-mail address: leonl@uj.ac.za introduction: participation in sport leads to physiological adaptations, especially at competitive and elite level. these adaptations may enhance performance, but they may also predispose the athlete to possible injury. aim: the primary aim of this study was to profile male and female junior provincial swimmers, using selected fitness tests. methods: a descriptive, quantitative research design was used. nine junior male (age=15.7±1.00) and nine junior female (age=15.1±0.78) provincial swimmers participated in the study. body composition was analysed using the following methods: body mass index (bmi), percentage body fat (bf%) and somatotype. concentric isokinetic peak torque for shoulder lateral and medial rotation were measured using a humac norm isokinetic dynamometer. antagonist-agonist ratios (lateral shoulder rotation divided by medial shoulder rotation) were also calculated. data was analysed using descriptive statistics (mean and standard deviation). results: bmi values of 22.5±1.23kg/m2 and 21.8±0.76kg/m2 were reported for males and females, respectively. males swimmers presented as ecto-mesomorphs (3.3-4.3-2.5), while female swimmers were characterised as meso-endomorphs (2.9-3.3-4.2). isokinetic antagonist-agonist ratios of 74.2% and 77.9% were found for the right and left sides in females, while the males exibited ratios of 71.7% and 67.6% for right and left, respectively. conclusion: both male and female swimmers demonstrated unique and sport-specific adaptations with regard to body composition and isokinetic shoulder peak torque values when compared to the general population or to other athletes. keywords: swimming, body composition, somatotype, isokinetics. p13: effects of an integrated movement programme on motor proficiency, visual-motor integration and scholastic achievement in grade one learners of quintile five schools in port elizabeth cassandra lister1, doctor maryna baard1 1nelson mandela metropolitan university presenting author e-mail address: listercassie@gmail.com introduction/background: globally, the association between physical fitness, motor proficiency and scholastic achievement has been well researched. however, information concerning the effectiveness of integrated movement programmes in preadolescent children from various socio-economic disparities, is less well studied. a lack of studies exists on the relationship between perceptual-motor development and scholastic performance in literacy and numeracy in children from low-middle income countries such as in sub-saharan africa. purpose (aim): to determine the effects of an integrated movement programme on motor proficiency, visual-motor integration and scholastic achievement in sixto nine-year-olds from quintile five primary schools in port elizabeth. methods: a quasi-experimental comparison group pre-test – post-test design was used in a preliminary study in two quintile five schools in port elizabeth. non-probability sampling resulted in 45 participants. test batteries included the beery-buktenica developmental test of visual-motor integration and the bruininks-oseretsky test of motor proficiency brief form. scholastic achievement was assessed using the department of education report card scores for numeracy, reading and writing compiled by the relevant teachers. statistical significance was set within a 95% interval (p<0.05). central tendency measures were reported. data were analysed with t-tests and anova and inferences were made based on results from chi-square tests, cohen’s d, and cramer’s v analysis. pearson’s correlation (r) was applied to determine associations between dependent variables. results: the experimental group showed a significant increase of 44% in motor proficiency over the four-week intervention period. motor proficiency in the control group declined by 4%. a significant positive association between motor proficiency and scholastic achievement in numeracy, reading and writing as well as in total scholastic achievement was found. findings indicated no significant correlation for scholastic achievement and visual-motor integration. conclusion: results highlight the strong relationship between motor development and cognitive abilities with regards to scholastic achievement and indicate the need for more longitudinal studies to be done on a national level. p14: two-year changes in body composition, physical activity, and selected metabolic risk factors among adolescents living in the north west province of south africa: the pahl study vincent masocha1, stanislaw czyz1, sarah. j. moss1, andries. m. monyeki1 1north-west university presenting author e-mail address: vmasocha@gmail.com background: childhood overweight and obesity has been found to be on the increase in lowto middle-income countries and is linked to both individual and clustered metabolic risk factors. the purpose of this study was to determine the two-year changes in body composition, physical activity (pa) and selected metabolic risk factors (abdominal obesity and blood pressure) among adolescents from the north west province of south africa methods: a total of 289 fourteen-year-old adolescents (116 boys and 173 girls) from the physical activity and health longitudinal study (pahls) participated in the study. body composition was measured according to the international society for the advancement of kinanthropometry (isak) standard procedures. pa level was measured using the international physical activity questionnaire (ipaq). abdominal obesity was determined using the waist circumference measurements and blood pressure was determined by omron mit elite plus. results: bmi classification for the whole group showed that 70.9% were in the normal weight category in 2011, and the number decreased (9.2%) to 63.9% in 2013. overweight gradually increased by 3.5% in 2012 and 4.1% in 2013. overweight increased by 2.2% among the boys compared to (12.2%) for girls (p ≤0.001). total physical activity (pa) level increased by 608.28 mets among the boys and 214.3 mets among the girls. participation in low-physical activity (lpa) increased by 8.2% for the whole group while moderate pa gradually decreased (15.2%) during the period. with regard to the metabolic risk factors (abdominal obesity and blood pressure-bp), waist circumference (wc) increased (2.97 cm) among the boys and (0.73 cm) among the girls. boys had significantly higher wc at every measurement point (p ≤0.001). for bp, 90.3% of the group was in the normal bp category in 2011 and the percentage decreased (5%) to 85.3% in 2013 while the percentage of those in the hypertensive / hypertensive category increased (5%) from 9.7 (2011) to 14.7% (2013). the increase was greater in girls than boys (p ≤0.001). mailto:leonl@uj.ac.za mailto:listercassie@gmail.com mailto:vmasocha@gmail.com conclusion: it was concluded that adolescent girls were more overweight, obese and less physically active compared to the boys over a period of time. additionally, boys showed a significant abdominal increase on one side, whilst on the other hand, an increase in the prevalence of hypertension was evident. keywords: body composition, physical activity, metabolic risk factors, adolescents p15: physical charactrristics and anthropometric profiles of kzn male taekwondo team musa lewis mathunjwa1, sibekezelo myaka1 1university of zululand presenting author e-mail address: mlmathunjwa@gmail.com background: taekwondo (tkd) is a martial sport that originated in korea. it is an olympic sport characterized by fast high kicks, spinning kicks and effective punches. aim: the purpose of this study was to examine the physical fitness and anthropometrical profile of the kzn male taekwondo team players during training performance after a 6 weeks of tkd intervention. methods: this was a prospective experimental study. thirty (n=30) active tkd athletes aged 18-25 years voluntarily participated in a 6-weeks interval tkd and resistance training. anthropometrical parameters (weight, height, bmi & fat percentage) and physical parameters (push-ups, sit-ups, speed, stork standing, sit & reach and straight leg raise test) were determined. data were analysed using t-test for independent samples. results: after 6 weeks of training, the male athletes showed a significant reduction in body weight (p0.05), bmi (p0.001), sbp (p0.05), rhr (p0.05), ss (p0.05), and fat % (p0.001) and significant improvement (p0.05) in sit ups, push ups, stork standing (p0.05) and even significantly higher speed and agility (p0.001). the improvement in horizontal jump was not significant after 6 weeks of taekwondo training. conclusion: our findings support the effectiveness of 6 weeks tkd training in improving body composition, cardiorespiratory response and physical performance that could enhanced combat skills of taekwondo athletes. key words: physical, anthropometric, interval, taekwondo and male. p16: effects of a six-week high interval taekwondo and resistance training on anthropometrical and physical parameters in kzn taekwondo athletes musa mathunjwa1, thabile sneyimani1, privilage ndlovu1, mlondi shozi1 1university of zululand presenting author e-mail address: mlmathunjwa@gmail.com introduction: taekwondo (tkd) is a combat martial art sport that emphasises fast spinning kicks. the aim of this study was to assess the impact of high intensity interval training on anthropometrical and physical parameters in kwazulu natal male and female taekwondo athletes. methods: thirty (n=30) active tkd athletes aged 18-25 years, volunteered for this study. the athletes were divided into control (n=15) white belts and experimental group (n=15) coloured belt. the experimental group performed high interval tkd and resistance training and control group performed recreational taekwondo training. the subjects (white and coloured belts) trained one hour in the morning and one hour in the afternoon, four times a week for six weeks. all subjects were pre and post tested on anthropometrical parameters (bmi, weight and height) and physical parameters [flexibility (seat and reach test) strength (push ups) endurance (sit ups) power (horizontal jump), speed (50-meter sprint) and agility (t-test) and vo2max (12-meter cooper test). results: the experimental group (taekwondo athletes) showed significant improvements (p˂0.05) in upper body muscle power, flexibility, speed and agility after training, whereas the vo2max did not change (p>0.05). conclusion: the findings of this study support the effectiveness of the 6 weeks high interval training in taekwondo and resistance training improves anthropometrical and physical parameters and contribute to performance to the fighting skills. key words: taekwondo, anthropometrical, bmi, shuttle run p17: overweight, obesity, chronic disease risk and physical activity levels of urban and rural women in zimbabwe. sinikiwe mhlanga1, takshita sookan1 1university of kwazulu-natal presenting author e-mail address: snixmh@gmail.com introduction: obesity is a well-recognised risk factor for various chronic diseases which is the largest cause of morbidity and mortality. maintaining a physically active lifestyle helps to keep a healthy weight and lowers the risk of chronic diseases. the aim of this study was to compare weight, chronic diseases risk and physical activity levels of rural and urban women in selected zimbabwean communities. methods: a descriptive, comparative, and cross sectional design was followed. a sample size of 280 women; age (35.17± 10.49 years), weight (68.88±14.65 kg) and height (1.62±0.05 meters) participated in the study. anthropometric variables, blood pressure, blood glucose and blood cholesterol were also measured among participants. international physical activity questionnaire, quality of life, and nutritional questionnaires were administered. descriptive statistics as well as independent t-tests and chi-square test of independence were used and the significance was set at p≤0.05. results: the results indicated an increase prevalence of overweight and obesity in urban women compared to rural women. there was a significant difference between urban and rural women in terms of bmi p=0.009, whr p=0.003 and wc p=0.005. regarding disease risk urban women were classified as high and very high risk compared to rural women, p=0.019. there was a significant difference between location and blood pressure p=0.025, with rural women having a higher raised blood pressure than urban women. a significant difference in cholesterol was noted between rural and urban women, p=0.003. a significant difference was noted between rural and urban women in the transport domain, p=0.046. there was a significant difference between energy consumption and location, p=0.0005. urban women had significantly high protein consumption p=0.007, and fat consumption p=-0.0005. conclusion: there is an increase in the prevalence of overweight and obesity in urban women compared to rural women. urban women also show an increased chronic disease risk compared to rural women. both urban and rural women showed high levels of physical activity and quality of life. high consumption of micronutrients was noted among urban women. the information gained in this study can assist health policy makers in the country to provide a platform to implement appropriate interventions. mailto:mlmathunjwa@gmail.com mailto:mlmathunjwa@gmail.com mailto:snixmh@gmail.com p18: acute quadreceps muscle radiating pain during fotball game, wrongly diagnosed as acute muscle strain. sudan cupping test sorted the problem. waeil mohammed1, samahir abuaraki elbkeet1, ahmed babiker elhag2, tarig abdulla abdulmajid1 1sport physiotherapy, sport medicine2 presenting author e-mail address: sudan31@yahoo.com no souleymane cisse is a 23 years fit football player, he started his professional carrier since 2008 .he is 176 cm high and his weight is 74 kg playing as defender at alhilall sport club the champion of the sudan. souleymane felt a sudden sever left thigh upper compartment pain during an official football game in the sudanese league 10 minutes before the end. it’s his first time to have such injury at this area. the pain appeared when he was tiring to change his position to pass the opportune player. the player said he felt very severe pain as if something is cut in the muscle that forced him to fall down. he asked for team doctor assistance and decision was made to send him out. he was not able to walk so he was transported on a stretcher. the first clinical examination showed a very tender, spastic left thigh upper compartment. the area was edematous and difficult for palpation. there was loss of function of the thigh and restriction in the normal movements. first aid was given for the player as the rice protocol (rest, ice, compression, and elevation). the player received cataflam 50mg, a non-steroidal anti-inflammatory medication (nsaid) two times a day after meals and baclofen 10mg, a muscle relaxant once per day. magnetic resonance imaging (mri) for the left thigh was scheduled for the next day and he was sent home to rest. the same night the player was not able to walk normally and couldn’t sit to do his prayers as every day and did that sitting on a chair. he was not able to step. the next morning there we unexplained reduction in the intensity of the pain. the player was sent for mri. we have been told that the mri report will be ready after 24 hours from the day of examination. at night the player said that the pain increased again. this was not characteristic for sport muscle injuries. the player continued his treatment as described. the next day themri result showed normal thigh muscles findings. regarding quadriceps strain various ways of grading muscle strains have been proposed [4, 5, 6]. factoring in pain, loss of strength, and physical exam findings in a grading system helps provide guidance for treatment, rehabilitation, and eventual return to play. table 1 provides an outline of a clinical grading system for muscle strains. clinical grading system for quadriceps strains grade pain strength physical exam 1 mild none or minimal loss of strength no palpable muscle defect 2 moderate loss of strength may feel a small palpable muscle defect 3 severe usually complete loss of strength often feel a palpable muscle defect this hassled us to consider the possibility of radiating pain from the lumbosacral area. we then started to ask the player more about complains of neurological origin. the player described feeling that the lower left limb is heavier than the right and a slight numbness and hotness at the planter of the left foot. then we considered conducting sudan cupping test. this is a newly applied dry cupping test, based on the use of different sized cups for cupping over certain areas of the cerv ical, thoracic and lumbosacral spine. the cups are applied sequentially over the vertebral column until the patient feels relieve of symptoms upon cupping a certain area, then the test is considered positive and that area is considered for wet cupping. the cupping test was done for the player using kangling chinese cupping sets. the pain disappeared when the cup was applied at his lumber are at the level of l4/ l5 vertebral disc space. only then, he was able to sit, and felt relieve of the heaviness, numbness, hotness of the left foot. that means positive sudan cupping test. the diagnosis of muscle pain of neurological origin was based on the fact that the pain decreased the next morning of the inj ury and then increased again, as well as the later neurological complains. the positive sudan-cupping test confirmed the diagnosis and thigh muscle strain was excluded. the player preferred to be treated with wet cupping. he underwent one session the next day after injury and went back to training 48 hours later. he received vitamins b1, b6& b12 with the already started treatment. the player’s condition improved dramatically and he was able to play two official games in the league within 7 days and an official african championship game at day ten after the injury. injury to the quadriceps muscle group can be painful and debilitating. strains and contusions of the quadriceps are common in athletics and result in lost time from training and competition. several studies have shown quadriceps strains commonly occur at the mid to proximal portion of the rectus femoris [1,2,3].pain in sport players does not always indicate sport injury. we have to think about radiating pain especially when the force that causes the injury is not strong enough to cause damage of the tissues. this nerve roots injury will produce a radiating pain which appear at the tissues innervated by the injured nerve or its branches. the sudan-cupping test is sensitive in such these cases in which instrumental investigations such as mri or muscle ultrasound cannot help in the diagnosis. we recommend the sudan-cupping test to be as initial screening test in sport injuries. the test is easy, simple, fast, cheap, simple and easy to apply test andwe recommend the sudan-cupping test to be as initial screening test in sport injuries. the test is easy, simple, fast, cheap, simple and easy to apply and available even in the field and during the competitions. vailable even p19: physical activity levels and sedentary behaviour of high school learners in soshanguve, gauteng province bhekiwe mtshali1, kebogile elizabeth mokwena2 1sasma, 2phasa presenting author e-mail address: senzekile3@gmail.com background: physical inactivity among adolescents is associated with an increasing prevalence of overweight and obesity (de vos, du toit and coetzee (2016). this is a public health concern as high school learners are becoming more and more sedentary and engage in poor dietary habits. the aim of the study was to investigate physical activity level and sedentary behaviour of high school learners in soshanguve, gauteng province. objectives of the study were to determine body mass index of the participants using height and weight measurements; to determine the prevalence of being overweight and obese; to determine physical activity levels and sedentary behaviour of participants. methods: a cross-sectional survey was used and data was collected using a validated tool, 2010 national youth physical activity and nutrition survey (lee, 2013). weight and height of participants were measured. mailto:sudan31@yahoo.com mailto:senzekile3@gmail.com results: seven hundred and eleven (n = 711) learners participated in the study. sixty five percent (65%) were females. the mean age was 15.92. (sd ± 1.68); mean weight was 58.12 (sd ± 13.78); mean height 1.57 (sd± 0.10); mean bmi 23.56 (sd ± 5.34).participants who had ideal weight were the highest 430 (60.5%) followed by overweight participants 126 (17.7%) and obese participants 115(16.2%). gender and age were statistically significant when correlated with obesity. the odds of females to being obese were 2.8 (ci: 1.99 – 4.09). four hundred and thirty one (61%) participants do not engage in any jogging or exercise while 264(39%) exercise for one hour or more per day. only 135(19%) exercise frequently during physical education classes. physical activity after school is as follows: 308(43.3%) do not engage in any physical activity after school while 309(43%) seldom engage in physical activity after school. only 94(13%) participants engage frequently in physical activity after school. three hundred and seventy five (53%) spend three hours or more watching tv; 301 (42%) on social network; 139(20%) studying and 95(13.4%) spend three hours or more on video games conclusion: the study showed low levels of physical activity and a high prevalence of overweight and obesity. strategies are needed to improve physical activity levels of learners. p20: a novel coaching cricket bat: can it be used to enhance the backlift and performance of junior cricket batsmen? habib noorbhai1, prof. tim noakes2 1cape peninsula university of technology, 2university of cape town presenting author e-mail address: habib.noorbhai@gmail.com background: in the current literature, it is questionable whether cricket bats in their current form and dimensions allow a young cricketer to hit the ball effectively. the aim of this study was to test the effectiveness of a novel coaching cricket bat among junior cricket batsmen with regards to enhancing performance and the direction of the backlift. methodology: a cross-sectional research study with analytical research methods was employed, in which two groups (coached: n = 12 (n = 6: experimental and n = 6: control) and uncoached: n = 35) of participants (ages 9 – 13) took part in both a pilot and intervention study. participants were required to use a novel coaching cricket bat in a coaching game format. biomechanical and video analysis was conducted in both the frontal and lateral planes. a student t-test (pilot group) and a two-way analysis of variance (anova), chi-squared test and effect sizes (intervention group) were performed. these analyses were performed using r at a significance level of α = 0.05. results and discussion: pilot study results demonstrated that participants scored an additional 100 runs when utilising the coaching cricket bat compared to a conventional cricket bat (p = 0.003). six weeks post intervention (training with the coaching cricket bat), the experimental group displayed improved performance (es = 5.41). players’ backlifts had subsequently become more lateral which may have promoted more effective ball striking as a result of this training effect. conclusion: the recommendation from this study is that coaches should encourage young cricketers to use the coaching cricket bat as it is perceived to be a potentially significant training aid for enhancing their performance and the direction of their backlift when they utilise conventional cricket bats in match play. key words: cricket batting, junior cricket, coaching cricket bat, batting backlift techniques, performance, coaching p21: the lateral backlift in cricket: does it affect other components of the batting technique? habib noorbhai1, prof. timothy noakes2 1cape peninsula university of technology, 2university of cape town presenting author e-mail address: noorbhaim@cput.ac.za background: this study aimed to investigate the batting backlift technique (bbt) among semi-professional, professional, county and current international cricket players. a key question was to investigate whether the lateral batting backlift technique (lbbt) is more common at the highest levels of the game. the secondary aim was to examine the extent to which the lbbt may affect other components of the batting technique (stance and preparatory movements). methodology: the participants in this study sample (n = 155) were south african semi-professional players (sp) (n = 69) and professional players (p) (n = 49), english county professional players (cp) (n = 25) and south african international professional players (sai) (n = 12) biomechanical and video analyses were performed on all participant groups. classifiers were utilised to identify the batting backlift technique type (bbtt) employed by all batsmen. all statistics and wagon wheels (scoring areas of the batsmen on a cricket field) were sourced online. a pearson’s chisquared test, student t-test and t-test were performed in this study. all analyses were performed using r (r core team, 2014) at a significance level of α = 0.05. results and discussion: this study found that a lbbt is more common at the highest levels of cricket batsmanship with batsmen at the various levels of cricket having percentages of the lbbt as follows: sp = 37.7%; p = 38.8%; cp = 40%; sai = 75%; p = 0.001. this study also found that batsmen who used the lbbt were more proficient at scoring runs in various areas around the cricket field (according to the wagon wheel analysis). a lbbt was shown to positively affect the stance and footwork of batsmen whereby most batsmen have an open stance at the crease. conclusion: a lbbt is more common at the highest levels of cricket batsmanship. cricket coaches should pay attention to the direction of the backlift with players, especially when correlating the backlift to various scoring areas on the field. further research is required to investigate the bbt among batsmen at junior and adolescent levels. key words: batting backlift techniques, semi-professional, professional, county, international, stance, scoring areas, cricket batting, cricket p22: the biomechanics of the achilles tendon: a digital image correlation study using a high-speed camera przemysław pękala1, brandon michael henry1, piotr kohut2, krzysztof holak2 1department of anatomy, jagiellonian univeristy medical college, 2agh university of science and technology, kraków presenting author e-mail address: pekala.pa@gmail.com introduction: annually, 5-10 new cases of achilles tendon (at) rupture occur per 100.000 people and affects both professional and recreational athletes. however, partial rupture is more common among professional competitors. while many authors have hypothesized on potential weak parts of the at, there is no scientific consensus. in the field of experimental biology, methods comparing changes in particular patterns during tensile tests, in real time, are used to assess and describe strain fields of material. the aim of this study was to evaluate the deformations of at specimens during tensile testing and provide comprehensive biomechanical data describing the strain patterns of the at in order to identify the weakest parts of the tendon. mailto:habib.noorbhai@gmail.com mailto:noorbhaim@cput.ac.za mailto:pekala.pa@gmail.com methods: the study was conducted on 28 at fresh-frozen cadaveric specimens. first, black dots were marked on the specimens. then, the specimens were mounted in a fatigue testing system (instron). during the tensile biomechanical test, the displacements of particular patterns were observed in real time using a high-speed digital camera (phantom). finally, the deformations were evaluated using digital image correlation techniques in the matlab environment. the strain was calculated based on distance changes between particular points in time. results: both 2d and 3d displacement fields were obtained. the average young’s modulus value was 264.8 mpa. based on averaged data, a slow motion movie of at strain during the tensile test was produced. the zones where strain was greatest and lowest were determined. the majority zones most vulnerable to strain were located in the middle portion of the at. based on the obtained data, a map of the strains of particular at regions was generated. conclusions: the presented biomechanical results on at weak zones during elongation will allow for an improved understanding of at physiology in healthy individuals. the obtained findings confirm previous hypotheses regarding weak zones in the middle of the at, which correlates with the commonly observed clinical picture. these results may help to improve of at repair techniques ad physiotherapy, as well as aid in injury prevention. p23: "what gives the achilles tendon a spin?" anatomy of the achilles tendon and its subtendons przemysław a. pękala 1, brandon michael henry 1, grzegorz tatoń 2, paweł kopacz 3, andrzej młyniec 4, tadeusz uhl 4, jerzy a. walocha 1, krzysztof a. tomaszewski 1 1department of anatomy, jagiellonian university medical college, krakow, poland, 2department of biophysics, jagiellonian university medical college, krakow, poland, 3department of forensic medicine, jagiellonian university medical college, krakow, poland, 4department of robotics and mechatronics, agh university of science and technology, krakow, poland presenting author e-mail address: pekala.pa@gmail.com introduction: rupture of the achilles tendon (at) is a common problem in sports medicine. the anatomical structure of the at has a strong impact on its pathophysiology and the therapeutic approaches for treatment of its disorders. the at is made up of three subtendons originating from: (1) lateral head of garstocenmous, (2) medial head of gastrocnemius, and (3) soleus muscle. functional loads affect the at in a very specific way, as the fibers of this tendon are not parallel to the axis of the lower limb. instead, they descend in an oblique fashion towards their insertion into the calcaneal bone. this study aimed to describe the morphology of the at (including the torsion of each subtendon) and its insertion. methods: a total of 116 fresh-frozen, tendon cadaveric specimens were dissected. microdissection tools were utilized to distinguish and separate the subtendons. a layer-by-layer blunt dissection technique was used to preserve the tendon’s fibers. a 3d printed tool designed by the authors was utilized to measure the angle of torsion of each subtendon. additionally, morphometric parameters of the at were measured. results: the mean angle of torsion of the deep fibers was 134.4 and 126.7 degrees, for the gcl and sol, respectively. in contrast, the mean torsion angle of the superficial fibers originating from the gcm was only 27.1 degrees. there were no statistically significant differences between left and right subtendons. the cross-sectional area of the at was significantly greater at the level of its insertion into the calcaneal bone than at the level of the musculotendinous junction (p<0.001). the mean length of the at’s insertion point was 45.7 mm and its mean width was 34.4mm. conclusions: the anatomy and torsion angle of at’s subtendons are significantly variable among individuals. however, in all specimens examined, the degree of torsion of the at’s superficial fibers was significantly less than that of fibers located in the deeper part of the tendon. such knowledge is essential for improving surgical reconstruction techniques and for providing a basis for the development of a computer model of the at. p24: age-related changes in the anatomy of the achilles tendon insertion przemysław a. pękala 1, anna drzymała 1, brandon michael henry 1, tomasz rok 2, wadim wojciechowski 3, lourdes kaythampillai 1, krzysztof a. tomaszewski 1 1department of anatomy, jagiellonian university medical college, krakow, poland, 2department of biophysics, jagiellonian university medical college, krakow, poland, 3department of radiology, jagiellonian university medical college, krakow, poland presenting author e-mail address: pekala.pa@gmail.com introduction: the insertion point of the achilles tendon (at) into the calcaneal bone (cb) is known to be highly variable. however, only a few studies have investigated the cause of this variability. the aim of this study was to evaluate if the at insertion point on the cb changes with age. methods: a total of 170 foot and ankle mri scans were evaluated to assess the at and its insertion into the cb using the follows measurements: distance from the most inferior point of the cb to the most inferior point of the at’s insertion, length of the at’s insertion, and height of the cb. the age of patients ranged from 4 to 76 years (mean: 35.64±13.29). patients were classified into three groups based on age: (i) <18, (ii) 18-65, and (iii) >65 years old. statistical analysis included one-way analysis of variance (anova) and fisher’s least significant difference (lsd) procedure. a p-value of <0.05 was considered as statistically significant. results: the mean distances from the most inferior part of the cb to the most inferior point of the at’s insertion were 1.18, 1.44, and 1.57 cm for groups i, ii, and iii, respectively. differences between these groups were statistically significant (f-ratio=5.13, p<0.01). to confirm the obtained results, the above mentioned distance was divided by the height of the cb and compared. the results of this analysis were also statistically significant (f-ratio=3.99, p<0.05). conclusions: this study found that the insertion point of the at changes with age, with the insertion point of the tendon located more superiorly on the calcaneus bone in older adults as compared to younger individuals. this anatomical variability may influence the biomechanical properties of the tendon and may, in part, explain why at pathologies are more commonly observed in older adults. p25: high ankle sprains. case series of conservative treatment with prp lervasen pillay1 1university of pretoria presenting author e-mail address: drpillay@absamail.co.za management of high ankle sprains. case series involving the use of prp and it’s efficacy. lervasen pillay (mbchb) pret.; (msc (med) sports med) wits objectives: using prp in high ankle sprain management helps to reduce pain and augment healing to make for more effective rehabilitation and quicker return to play. mailto:pekala.pa@gmail.com mailto:pekala.pa@gmail.com mailto:drpillay@absamail.co.za methods: athletes were assessed and either clinically, dynamic xrays, ultrasound or mri . diagnosis of high ankle sprain was made involving aitfl, pitfl, itl, iol or combinations. a standard rehabilitation was done with all athlete including acute management, non weight bearing booting, early mobilisation and proprioception together with a strength program. a visual assessment pain scale was used to monitor pain and progress rehabilitation accordingly. those athletes that were out for a longer period than 10 days had a cardiovascular/fitness program added to their rehabilitation. results: over 6 seasons a total of 55 high ankle sprains were treated of a total of 597 athletes (9.2% or 1.3 injuries per 1000 playing hours) in sub-elite and elite football players. a total of 42 players opted for prp treated .twelve opted for conservative treatment. one was surgically treated. grade 1 strains 21 athletes opted for prp treatment with an average return to play of 7 to 10 days with. the remaining 8 athletes opted for conservative treatment with return to sport 3 to 4 weeks. grade 2 sprains had 20 athletes opting for prp treatment and return to sport was 3 weeks. the remaining 2 athletes returned to sport in 6 weeks. grade 3 sprains, one was treated surgically, one opted for conservative treatment and one athlete considered prp treatment. the surgically treated athlete returned to sport at 8 weeks. the conservatively treated athlete returned to sport in 12 weeks. the prp managed athlete returned to sport in 8 weeks. none of the patients suffered re-injuries and they follow a regular proprioception program after rehabilitation. conclusion: using prp as an adjunct in conservative treatment appears to allowing for earlier return to sport without high risk of re-injury. conservative treatment may be comparable to surgical treatment in more severe injuries. p26: the use of regenerative medicine techniques in the treatment of hip labral injuries: a case study lervasen pillay1 1university of pretoria presenting author e-mail address: drpillay@absamail.co.za background: this case highlights the consideration of use of non-surgical management in hip pathology using prolotherapy in the difficult to manage case. history: a 31 year old elite endurance runner presented with ongoing and worsening right hip pain and posterior thigh pain for a period of 5 months. non clinical aspects revealed the athlete suffering from a depressive mood as she had not been active for 5 months. management: the patient presented 5 months later with the above history. available information revealed a anterosuperior labral detachment. the antero-lateral approach of the hip joint was used to infiltrate 2.5mls of 50% dextrose water together with 5mls of 2% lignocaine (prolotherapy) using a 5ml syringe and a 20g spinal needle. this was done under ultrasound guidance. the athlete was advised to start returning to road running, progressing from minimal mileage at slow pace to normal from after the 48 hours rest period post injection. during this progressive load period she should continue with strength and flexibility exercises prescribed to her. response to management: the athlete began the return to sport process after 48 hours and after 6 weeks revealed a full pain free range of movement of the hip running an average of 120 kilometres per week at an improved pace of 3.50 minutes per kilometre. less than one year later, the athlete had no returning issues, place in a local half marathon and achieved a personal best at a european meeting. conclusion: sports medicine practitioners should revisit the idea of using cost effective prolotherapy (with dextrose and lignocaine) as a treatment option especially in those athletes who are not improving with conventional treatment approaches and have no surgical treatment indication. keywords: hip labrum, prolotherapy, hip pain, runner hip p27: exercise therapy: effectiveness on activities of daily living on hiv lung disease patients karabo raphokwane1, dr bf mtshali2 1pasa, 2sasma presenting author e-mail address: karabo.raphokwane@smu.ac.za background: pulmonary conditions are opportunistic diseases in hiv patients, because of their pathology they seem to make the patient frail and decreasing their participation in performing activities of daily living (adls) thus decreasing health related quality of life. hrql does predict survival of these patients. the effectiveness of a specific physiotherapy exercise therapy on patients with hiv related lung diseases in dr george mukhari academic hospital (dgmah) are unknown and thus creating a gap for rehabilitation. aim: the study aimed at measuring the effectiveness of an exercise therapy on activities of daily living in patients with hiv related lung disease. methods: an experimental design comprising of one group pre and post-test was done. three phases were used: pre and post evaluation measured with st george's respiratory questionnaire (sgrq) and a six week intervention using australian lung foundation pulmonary toolkit (alfpt) exercise program. 61 patients were selected using sample of convenience from the population. data was analysed using spss version 21.0 and sgrq manual. the significance level was set at 0.05 results: the participant’s age ranged from 22 to 67 years old with mean age of 42.92 and sd ± 9.105; there were more females (60.7%) than males (39.3%). common diagnosis was ptb at 73.8%. thirty percent (30%) of the participants felt breathless when doing daily activities pre intervention which improved post intervention with only 2% feeling the symptoms. house work was reported to take a long time or having to stop for rests in between with fifty nine percent (59%) of the participants, only twenty six percent (26%) remained the same after intervention. initially fifty four percent (54%) felt uncomfortable playing sport which limited their social integration which improved post intervention when only eleven percent (11%) remaining. conclusion: the study shows that exercise therapy improves participatory in activities of daily living in patients who have hiv/aids related lung diseases. implications: there needs to be specific physiotherapy pulmonary rehabilitations programmes for patients with hiv related lung diseases to improve their quality of life. p28: resistance training reduces t helper cytokine levels but not cardiometabolic risk factors in hiv-infected individuals receiving art. takshita sookan1, michael j. ormsbee2, jose antonio3, nombulelo p. magula4 1university of kwazulu natal, biokinetics, exercise and leisure sciences, 2florida state university, institute of sport science and medicine and the centre for advancing exercise and nutrition research on aging, 3nova south-eastern university, department of biology, 4university of kwazulu natal, department of internal medicine presenting author e-mail address: sookan@ukzn.ac.za mailto:drpillay@absamail.co.za mailto:karabo.raphokwane@smu.ac.za mailto:sookan@ukzn.ac.za background: lipodystrophy syndrome and cardiometabolic diseases are conditions that affect hiv-infected individuals on antiretroviral therapy (art). a shift from t helper (th) 1 to th2 cytokine profile is associated with disease progression and has been linked with lipodystrophy. the aim of this study was to determine the effect of combined resistance training and whey protein on body composition, th1 and th2 cytokines and cardiometabolic risk in hiv-infected individuals receiving art. methods: forty hiv-infected participants (40.8 ±7.7 yrs, 70.8 ±16 kg, bmi 30.9 ±7.2 kg/m2) receiving art (≥18 months) were randomly assigned either whey protein/progressive resistance training (prt) (n=18), placebo/prt (n=14) or as a control (n=8). participants received either 20g whey or placebo (maltodextrin) pre and immediately post each prt session. whole body rt was performed 2/week for 3 months with loads progressing from 40-85% of one repetition maximum (1rm). measurements including height, weight, waist and hip, dexa and 1rm testing were performed (pre = t1) and after 3 months (t2) prt program and 3 months (t3) following cessation of the prt program. additionally, venepuncture was performed to measure systemic immune, inflammatory and cardiometabolic risk markers. statical analysis included two-way anova with multiple comparisons in the prt groups and one-way anova with repeated measures in the control group. alpha was set at p ≤ 0.05. results: there was a significant (p 0.001) main effect of time for prt groups and control group for the homa-ir index. post-hoc testing demonstrated that homa-ir index significantly increased in all 3 groups. there was a significant (p = 0.05) main effect of time for prt groups for the th2 cytokine il-10. there was a significant main group effect for cd8% (p = 0.05), il-10 (p = 0.01), il-13 (p = 0.05) and il12 (p = 0.02). post hoc testing revealed a significant group effect with placebo/prt lower over the 3 time points for il-10 (p = 0.008) and il-12 (p = 0.016). conclusion: hiv serves as both a metabolic and an inflammatory challenge. our study demonstrated that a prt programme can decrease antiinflammatory and pro-inflammatory cytokines possibly reflecting reduced systemic inflammation in hiv-infected individuals. p29: oat beta-glucan: an alternate cholesterol management nutrient for athletes bernice venter1 1bsc med (hons) nutrition and dietetics presenting author e-mail address: bernice@atlife.co.za the results from the sanhanes (south african national health and nutrition examination survey) data published in august 2013 typically display a cholesterol crisis. one out of four participants 15 years and older have an abnormally high serum total cholesterol (23.9%) and ldl cholesterol (28.8%), and one out of two an abnormally low hdl cholesterol level (47.9%). hypercholesterolemia is a major risk factor for cardiovascular disease statins are the most widely used drugs to lower blood cholesterol in people with hypercholesterolemia. muscle symptoms such as pain (myalgia), myopathy and rhabdomyolysis are the most common side effects of long term statin treatment. statin-related muscle symptoms (pain, weakness and injury) may be significantly exacerbated by intense physical activity and these symptoms are further enhanced by age an alternative treatment for athletes with hypercholesterolemia is thus warranted in many cases. bioactive oat beta-glucan has been proven to reduce blood cholesterol levels. high cholesterol is a risk factor in the development of coronary heart disease. a european food safety authority (efsa) article 14 claim exists for oat beta-glucans inferring a reduction in the risk of heart disease. this benefit is achieved with a daily intake of 3g bioactive oat beta-glucan. additionally, an efsa article 13.1 approval exists for oat beta-glucans for blood glucose control and gut health. oat beta-glucan has been shown to prolong glucose absorption which may affect energy supply in endurance exercise, may increase time to exhaustion and recovery from fatigue oat beta-glucan should thus be considered in terms of cholesterol management, glucose control and gut health for athletes p30: release parameters of the best jump shots in elite male zimbabwe basketball players. eberhard munetsi tapera1, morgan patrick gundani1, lateef .o . amusa (late)2, daga makaza1 1national university of science and technology, 2university of venda presenting author e-mail address: emtapera@gmail.com this study investigated release parameters (rps) (angle of release (aor), velocity of release (vor), height of release (hor) and spin of release (sor) of the clean shot (cs) , scored by zimbabwe male league basketball players (zmlbbps). cs represents the most accurate jump shot (majs). data for the study was collected from 26 male players, randomly sampled from the bulawayo basketball association. each player executed ten successive and uncontested jump shots (jss) each from the free throw line. these shots were videotaped in the sagittal plane, using standard videography protocols. a panasonic camera (model vdrd1160) placed 10.7 m away from, and perpendicular to the plane of motion of the subjects and mounted on a tripod 1.9 metres high, was used to capture the jss. mean (± s.d.) values of aor, vor, hor and sor were computed from the video data to describe the rps of majs made by zmlbbps. the study found that the rps (aor, vor, hor and sor) of majs made by zmlbbps were 55.5±8.4º;5.4±1.33/s;2.5±0.4m and 3.6±1.6 rev/s. it is concluded from the study that majs of zmlbbps are executed using comparable aors, very low vors, low hors and high sors in comparison to rps used by players elsewhere, in executing js. it is therefore recommended that zbbps design practices that compel players utilize high vor, and high hor when practicing for js and that zmlbbps coaches use height as a criterion for selecting players for bb. keywords: basketball, jump shot, velocity, successful shots, angle, spin p31: selected release parameters of the clean shots executed by male league zimbabwe basketball players. eberhard tapera1, lateef o. amusa2, daga makaza1, daniel t. goon3, morgan p.d. gundani1 1national university of science & technology, bulawayo, zimbabwe, 2university of venda, 3university of fort hare presenting author e-mail address: emtapera@gmail.com basketball is very popular in zimbabwe. shooting, an important skill in this sport, is achieved performing mostly the jump shot (js). the low conversion rate of this shot suggests that zimbabwean league basketball players have difficulties in executing js.js can be performed with varying levels of accuracy, the most accurate of which is the clean shot (cs), in which the ball is shot into the hoop without touching either the rim or the back-board. this study investigated release parameters angle of release (aor), velocity of release (vor), height of release (hor) and spin of release (sor), used to perform the cs by zimbabwe male league basketball players. data for the study was collected from twenty six male players recruited from the bulawayo basketball association league. each player executed ten successive and uncontested jss from the free throw line. the shots were videotaped in the sagittal plane, using a panasonic camera, model vdr d1160, placed 10.7m away from, and perpe ndicular to, the shooting plane of the subjects, and mounted on a tripod 1.9 meters high. fifty six css were selected for processing and analysis. the video mailto:bernice@atlife.co.za mailto:emtapera@gmail.com mailto:emtapera@gmail.com data obtained from the css selected were reduced to single units of analysis using any converter software, and then analysed for release parameters using quintic coaching 4.07 v 17 motion analysis software. mean (± s.d.) values of aor, vor, hor and sor, parameters used to characterize the css, were found to be 55.5±8.4º; 5.4±1.33/s; 2.5±0.4m and 3.6±1.6 rev/s, respectively. the study further found that zimbabwean players execute css using aors which are similar to, vors and hors which are lower than, and hors and sors which are higher than, the same rps used by players elsewhere, in executing the same shot. it is recommended that zimba bwe basketball coaches design drills practicing js that will compel players to utilize high vors and hors and low sors, and that the same coaches use height as one of the criteria for identifying basketball players. keywords: basketball, jump shot, velocity, successful shots, angle, spin p32: effects of exercise intensity on heart rate variability in children anneke van biljon1, andrew mckune2, katrina dubose3, unathi kolanisi1 1university of zululand, 2discipline of sport and exercise science, university of canberra research institute for sport and exercise, faculty of health, university of canberra, australia, 3department of kinesiology, east carolina university, greenville, nc, usa presenting author e-mail address: vanbiljona@unizulu.ac.za background: the associated health benefits of exercise correlate to intensity rather than duration of exercise. vigorous exercise intensity has received a lot of interest in cardiovascular autonomic adaptations. however, paediatric research on intensity-based prescription for autonomic adaptation are inconclusive. the purpose of this study was to investigate the effects of three isocaloric exercise programmes on heart rate variability in children. methods: one hundred-and-nine children (11.07 ± 0.81 y) were conveniently assigned to one of four groups 1. moderate continuous intensity training (mcit, n = 29) at 65% – 70% predicted maximum heart rate (mhr) 2. high intensity interval training (hiit, n = 29) at > 80% predicted mhr and 3. hiit and mcit combined (hiit + mcit, n = 27) 4. control group (ct, n = 24). all exercise groups trained for three sessions per week for 5 weeks, a total of 15 sessions. heart rate variability was analysed with a suunto t6 heart rate monitor. linear data was computed in time and frequency domains, and quantitatively from the poincare plot analysis. data analysis a two-way analysis of variance (group x time) was used to evaluate the effects of training on all hrv parameters (p 0.0125). effect sizes (es) were calculated to assess the magnitude of difference. results: time domain hrv analysis revealed significant group x time interactions in ibi (p 0.0001), sdnn (p = 0.0003), rmssd (p = 0.0001), nn50 (p = 0.0015) and pnn50; (p = 0.0002). rmssd was significantly higher in hiit (94.41 ± 38.32ms; es = 2.69) than in mict (70.15 ± 47.82ms ;es = 1.75) and hiit + mict (67.71 ± 37.28ms; es = 1.06). hiit also showed superior results in ibi (es = 2.94) sdnn (es = 2.22) nn50 (es = 2.47) pnn50 (es = 2.78) and sd1 (es = 2.69) compared with mict and hiit + mict. conclusion: hrv appears to be strongly influenced by exercise intensity with hiit showing greater parasympathetic modulation in time domain and non-linear parameters of heart rate variability in children. p33: bridging the gap between inpatient rehabilitation and outpatient health and wellness in spinal cord injured patients candace vermaak1, dr. suzanne ferreira1, prof. elmarie terblanche1 1stellenbosch university presenting author e-mail address: candace.kok@gmail.com background: a spinal cord injury is a devastating and life changing neurological event that impacts many facets of life. one of the challenges include healthy living. in south africa this outcome is seldom achieved due to the lack of physical activity opportunities. without regular physical activity the physical gains that were achieved in hospital are easily diminished or lost, which contributes to rehospitalisation and prevents community reintegration (mothabeng, 2011). objective: to determine whether an intervention based on identified barriers and facilitators to physical activity can be successful in promoting health and wellness in people with a spinal cord injury. design: an experimental research design incorporating both quantitative and qualitative methodologies was used to execute the study. methods: a self-developed research questionnaire was used to gather information regarding the barriers and facilitators to physical activity. this data was used to design and implement a 16-week intervention in two different environments (formal exercise setting and community based setting). the success of the intervention was measured by physical tests, the reintegration to normal living index questionnaire and the research questionnaire. subjects: fifty-seven people with a spinal cord injury completed the research questionnaire and 16 participants partook in the intervention. results: the intervention showed that the participants from both groups improved their physical abilities (strength, endurance and functional abilities) and their satisfaction with community participation. the barriers that were identified prior to the intervention were also significantly reduced, especially in the community based group. at the end of the intervention the participants also acknowledged that physical activity was beneficial and important and that they would continue to stay physically active post-intervention. discussion and conclusion: people with a spinal cord injury face many barriers in being physically active, however, by reducing the barriers to physical activity a community based physical activity program can be successful in introducing people with a spinal cord injury to healthy living. although some of the environmental and program barriers remained, the personal facilitators that were identified were enough to ensure physical activity adherence and even led to growth of the groups and the establishment of new groups within other communities. p34: a comparison between the cardiorespiratory responses of a speed versus an incline motorized treadmill protocol. yolandi willemse1, jana storm1, martinique sparks1 1north-west university presenting author e-mail address: yolandi.willemse@nwu.ac.za objectives: to compare the cardiorespiratory responses attained by elite male university-level distance runners of two maximal aerobic capacity (vo2 max) graded exercise test (gxt) protocols on a motorized treadmill. design: a once-off cross-sectional design using elite male university-level distance runners. methods: two gxt protocols were used, namely the adapted incremental speed protocol (aisp) and the incremental speed and incline protocol (isip). both protocols commenced from a starting speed of 10 km/h, where after the aisp continuously increased by 1 km/h speed increments and the isip increased by 1 km/h speed increments up to 15 km/h, after which 1% gradient increases were applied. both treadmill gxt protocols were performed to complete exhaustion. cardiorespiratory responses (oxygen consumed, carbon dioxide produced, oxygen utilized, minute mailto:vanbiljona@unizulu.ac.za mailto:candace.kok@gmail.com mailto:yolandi.willemse@nwu.ac.za ventilation, heart rate, time to exhaustion and respiratory exchange ratio) were used to determine exercise intensity markers, namely ventilatory threshold and respiratory compensation point (rcp). rating of perceived exertion was measured after completion of each test level. results: the vo2 max value (67.6 vs. 65.0 ml/kg/min), as well as the relative rcp value (64.1 vs. 60.7 ml/kg/min) attained by the isip, was statistically and practically higher (p0.8; r0.5) than those of the aisp despite the longer time to exhaustion (11.4 vs. 13.6 min) and the longer time to the attainment of rcp (11.1 vs. 8.8 min). conclusion: the isip vo2 max result exceeded that of the aisp and it is consequently considered the more appropriate gxt protocol to attain the highest cardiorespiratory responses in an elite male university-level distance running population. p35: measuring functional balance in the elderly: comparison of three balance tests paola wood1, lean-mari rossouw2, denise gous2, welmari cousins2 1university of pretoria, department of physiology and semli, 2university of pretoria, department of sport and leisure sciences presenting author e-mail address: paola.wood@up.ac.za background: the global population of men and women over the age of 60 years is estimated to be approximately 841 million, and is predicted to reach two (2) billion by the year 2050. falls in the elderly often lead to hospitalisation and high medical costs and have been attributed to poor balance. different balance tests are used to measure balance in the elderly but it is unclear whether these tests are interchangeable with one another to render comparisons possible. the aim of the current study was to compare the functional reach (fr) test and the timed-up-andgo (tug) test, with the fall risk measured by the biodex balance system sd. methods: a nonexperimental, retrospective descriptive correlational design was used. data consisting of height (cm), weight (kg), waist-hip ratio, bmi (kg.m2.), fr test (cm), tug test (sec) and fall risk measured with the biodex sd balance machine, collected in a south african elderly sample (n=31) in 2015, was analysed using nonparametric, descriptive statistics. spearman rank order correlation was used to assess the relationship between the three (3) balance tests. alpha was set 0.05 and categories of r classifications were set as weak (r0.6). results: a weak relationship with no significant correlation was observed between the fr and tug tests (r = 0.32, p = 0.866), fr test and biodex fall risk (r = 0.014, p = 0.941), and between tug test and biodex fall risk (r = 0.349, p = 0.055). the tug test classified all the participants as low fall risk, whereas the fr test and the biodex balance system sd both classified two (2) participants as high fall risk. conclusion: the fr, tug and the biodex balance assessment cannot be used interchangeably with one another, in an elderly south african population, despite all three (3) tests being considered to be valid and reliable tests to measure balance in the elderly. further research should investigate the role of obesity on fall risk and the reliability and validity of these balance assessments in the elderly who are overweight or obese. oral / “flash” poster presentation pp1: the effect of unilateral transtibial amputation on locomotion and postural stability: a systematic review sarah arnold1, dr suzanne ferreira1 1stellenbosch university presenting author e-mail address: 16465865@sun.ac.za introduction: the locomotion and balance of trans-tibial amputees are affected by numerous factors. these factors may either positively or negatively influence the functional ability of this population. in order to implement relevant and effective rehabilitation programmes it is important to gain an understanding of the extent and manner in which the functional ability of trans-tibial amputees is affected. the purpose of this review was therefore to systematically review the literature available relating to the biomechanics of walking gait and postural stability in terms of muscle activation, asymmetry and the effect of rehabilitation methods in trans-tibial amputees. methods: three databases were used for the literature search including pubmed, cinhal and medline. google scholar was used to find additional articles pertaining to the subject. mesh terms including, unilateral trans-tibial amputees, gait, emg, kinematics, balance and asymmetry. titles and abstracts went through an individual two person review process according to strict criteria agreed upon beforehand. articles fitting the criteria then underwent a full review with refined criteria by the same two reviewers. results: the review of the literature indicated that the walking gait of trans-tibial amputees in comparison to that of able-bodied counterparts is greatly affected. several articles indicated that trans-tibial amputees have an asymmetrical gait and that the compensations negatively affect the functional ability of this population. one article however discussed that the asymmetry in step length and the foot forward placement found may be a functional compensation to help decrease the risk of falls. it was also made evident through the literature that factors including, prosthetic foot type, the socket fit and age may influence gait and postural stability in unilateral trans-tibial amputees. conclusion: along with the external factors that may influence the gait or postural stability of unilateral trans-tibial amputees it is clear that the loss of structure and musculature results in asymmetrical and compensatory movement patterns. unfortunately, there is limited research relating to the comparison of rehabilitation techniques of unilateral trans-tibial amputees. future studies should aim to differentiate the efficacy of different rehabilitation strategies based on the age of the amputee. pp2: the use of heart rate variability and recovery to determine the fitness levels of a cohort of university-level rugby players christo bisschoff1, prof ben coetzee1, dr. cindy pienaar1 1north-west university presenting author e-mail address: 13234358@nwu.ac.za the purpose of this study was to determine if heart rate variability (hrv) and heart rate recovery (hrr) can be used to determine the fitness levels of a cohort of university-level rugby players. 24 university-level rugby players (age 20.1 ± 0.41 years; height 182.70 ± 6.20 cm; weight 89.70 ± 12.70 kg) of a south african university’s rugby institute participated in the study. hrv was measured with the bioforce heart rate variability system (performance sport inc., washington, usa) using a fix polar heart rate transmitter belt (polar team pack, polar electro oy, kempele, finland) as well as a wireless receiver and software that was downloaded on an ipad. during the test day players’ fasting baseline hrv (baseline hrv) values were taken. this was followed by the post-breakfast hrv measurement (pre-yo-yo ir1 hrv). players were then required to perform the yo-yo intermittent recovery test level 1 (yo-yo ir1) while they were fitted with a portable gas analyser apparatus (cosmed k4b2). after completion of the test, hrr was taken after 1 and 3 minutes as well as their hrv (post-yo-yo ir1 hrv). significant correlations (p ≤ 0.05) were found between pre-yo-yo ir1 hrv and heart rate (hr) at the respiratory compensation point (rcp-hr (bpm)) (r = -0.468) as well as oxygen mailto:paola.wood@up.ac.za mailto:16465865@sun.ac.za mailto:13234358@nwu.ac.za uptake at the rcp (rcp-vo2max (% of vo2max )) (r = 0.476), respectively. a forward stepwise regression analysis showed that hr at ventilatory threshold 1 (vt1-hr (bpm)) contributed significantly (p ≤ 0.05) to the post-yo-yo ir1 hrv with a variance of 39.8%. the final yo-yo ir1 level also contributed significantly (p ≤ 0.05) to the 3 minute post-yo-yo ir1 heart rate recovery (hrr) with a variance of 16.5%. in conclusion, hrv and hrr have the potential to act as affordable and easy measurement tools of team sport participants’ fitness levels. pp3: big data analytics in sport, exercise and physical activity: a systematic review jill borresen1, prof martin schwellnus1 2 3, prof philip treleaven4 1sport, exercise medicine and lifestyle institute (semli) & section sports medicine, faculty of health sciences, university of pretoria, south africa, 2international olympic committee (ioc) research centre, south africa, 3emeritus professor, faculty of health sciences (emeritus professor), university of cape town, south africa, 4professor of computing university college london presenting author e-mail address: jill.borresen@up.ac.za introduction: computational sport is a new discipline applying systematically big data analytics to sport, exercise and physical activity. advances in sensing technology have improved our ability to continuously monitor health, physiological and performance indicators. although many people are now collecting a wealth of activity, nutrition, and health data from devices, apps and internet-enabled equipment, and may also be using data science methodologies for analysis; big data analytics in the areas of sport, physical activity, exercise and medicine is highly fragmented. the aim of this study was to perform a systematic review of big data analytic technologies and methodologies and their application in the areas of sport, exercise and physical activity. methods: we conducted an electronic search of peer-reviewed studies published in “pubmed” until 31 july 2017 using combinations of search terms relevant to big data analytics and physical activity/sport/exercise. studies were included if they were published in english, involved human participants and included 1) the measurement of, or outcome measures related to engaging in physical activity, exercise or sport and 2) data analysis, or the assessment of analytic techniques involving one or more big data analytics methodologies. reviews, editorials and protocols were excluded. results: the initial electronic search retrieved 594 studies, and after applying exclusion and inclusion criteria 285 papers were reviewed. preliminary results of this review suggest that approximately one third of studies applied big data analytics to activity classification/recognition, a quarter applied these techniques to prediction/forecasting and another quarter to the validation of indirect measurements, with 10% being applied to the characterisation of traits. conclusion: big data technologies have potential to provide insight into people’s actions and to determine patterns and predict future outcomes and trends. examples include assessing the efficacy of new interventions designed to change health behaviours, or to prevent and manage injuries and illness, and improve performance in participants of sport and exercise. in so doing they may have a profound impact on how we address lifestyle diseases, how we create personalised and predictive medical care, and how we contribute to knowledge advancement in sports to achieve high performance outcomes. pp4: if the shoe fits… should you wear it? a calcaneal stress fracture in a female recreational runner james burger1, wayne derman1 2 3 1isem (sun), 2ioc research centre, 3fifa medical centre of excellence presenting author e-mail address: burger.james.w@gmail.com case history: a 43-year-old female, recreational runner presented with severe tenderness of the right calcaneus. she had been running for the past 12 years with no account of severe injury. on further history, it revealed that she had recently changed from a conventional shodto a true minimalist type running shoe. within 3 weeks of this conversion she had completed a 21km and 5km race respectively. the day after completion of the 5km race she struggled to weight bear on her right foot. physical examination / findings: on examination, she had unilateral, generalised tenderness over her right calcaneus. differential diagnosis: stress fracture of the calcaneus plantar fasciitis bruised heel heel spur retrocalcaneal bursitis test results: magnetic resonance imaging (mri) of the hind foot showed a linear stir-hypointense line extending from the posterosuperior to the anteroinferior aspect of the calcaneus indicating a complete fracture of the right calcaneus, with associated bone marrow oedema. a dexa bone scan revealed normal bone mineral density (bmd) and the relevant blood tests were all within the normal range. final diagnosis: complete fracture of right calcaneus discussion: there has been a trend amongst runners towards minimalist shoes, which have possible performance benefits and may potentially reduce injuries through strengthened musculature, reduced forces, and a more natural gait. the benefits and risks related to minimalist shoes has been a much-debated topic in recent years. in the transition period of moving between traditional and minimalist footwear, there may be added stress placed on the bones as there is reduced cushioning and often there needs to be a transition from rear-foot strike to mid-foot or fore-foot strike. calcaneal stress fractures are the most common stress fracture of the foot in women, typically occurring in distance runners. in the case of this recreational runner, the stress fracture developed in a few weeks following the change in her shoe type and progressed to a completed fracture of the calcaneus. following a period of no/low weight bearing, a graded return to sport programme was followed successfully without incident. pp5: endocrine response to small-sided games and match play in elite u19 south african soccer players simon de waal1 1lecturer stellenbosch university sport science department presenting author e-mail address: simondw@sun.ac.za purpose: small-sided games (ssgs) are used worldwide with the intention of stimulating significant physiological adaptations in players that are specific to match demands. the external load of ssgs and matches in soccer is well documented, but far fewer studies are aimed at measuring the internal response to these activities. the endocrine response to ssgs and matches in soccer is less well known although the respective mailto:jill.borresen@up.ac.za mailto:burger.james.w@gmail.com mailto:simondw@sun.ac.za hormones; cortisol, testosterone and dehydroepiandrosterone (dhea) provide a valid measure of training load and total stress in several other methods of exercise. this study aimed to measure the internal endocrine response to training and matches and identify any variations between playing position and whether ssgs were preparing the players for match demands. methods: 22 elite male soccer players (16 – 23 years old), divided into positional subcategories of goalkeeper (n = 4), defender (n = 7), midfielder (n = 5), and attacker (n = 6) provided saliva samples; at rest, in response to 11v11, 7v7, and 4v4 ssgs, friendly and competitive matches, and a yoyo level two intermittent endurance test (yoyoii). cortisol, testosterone, t:c, and dhea concentrations were analysed using an ultra-highperformance liquid chromatographic method with mass spectrometric detection in response to small-sided games and matches. statistically, hormones were analysed through one and two way anova’s to compare different time points and positions. results: cortisol (ng/ml) increased significantly (0,70 ± 0,40 sd to 3,94 ± 3,26 sd) from resting values in response to competitive match-play immediately after the match amongst the squad as a whole (p < 0.01). cortisol increased significantly during all small-sided games (p < 0.05). t:c ratio (ng/ml) significantly decreased (0,89 ± 1,93 to 0,19 ± 0,28) from resting values in response to competitive match-play (p < 0.01) while testosterone showed no significant changes in response to match-play. no significant differences were found between the endocrine response of all positional subgroups over any ssgs or matches. dhea presented no significant changes between all time-points and t:c ratio remained constant throughout the eight month testing period. ssgs presented no significant differences in endocrine response based on the number of players on the field. yoyo2 produced comparable endocrine response to those at rest amongst the squad as a whole. conclusions: ssgs do not prepare soccer players for matches because they do not stimulate the same stress response than matches. the stress response is likely correlated to more than just physical exertion, therefore cortisol could be used as an indicator of total stress including anxiety and emotional stress as opposed to physical stress alone. different positions do not result in different internal responses to training and matches regardless of differing external positional requirements. ssgs as a method of training seems to present no risk of overtraining. future studies should seek to correlate cortisol, testosterone and dhea with other, more affordable measures of internal training load or be used in conjunction with external training load measures. future studies should perform repeated testing on smaller study samples due to the high intra-individual variability of endocrine response between time-points. keywords: small-sided games; t:c ratio; match-play; soccer pp6: effects of regular aerobic exercises on lung function in zimbabwean elderly men adiele dube1, morgan p. d. gundani2, dr emmanuel sithole3 1emergency medical technician/ sports scientist, 2lecturernust sports science dept, 3medical practitioner presenting author e-mail address: adieledube@yahoo.com background: in healthy elderly persons, effects of natural aging, obesity, physical inactivity and pathological effects that may have arisen from youth are the main factors that affect respiratory function. the present study aims at evaluating the effect of regular aerobic exercise training on improving lung function in elderly people. materials and methods: twenty-two elderly men with low level physical activity were the subjects. a digital scale (seca 710r) was used to measure weight (kg), height was measured by stadiometer (cm) and bmi (kg/m²) was calculated. respiratory indices were mild: forced expiratory volume in one second (fev1), forced vital capacity (fvc), and fev-1/fvc ratio in 1 second ere fev1 control group 3.19±0.30 and 3.19±0.30; intervention group 3.12±0.22 and 3.13±0.22. fvc control group 3.35±0.21 and 3.38±0.39; intervention group 3.53±0.43 and 3.62±0.43. both fev1 and fvc indices did not reach the predicted values. there were no significant differences in pre and post exercise respiratory indices in the control group. there were notable improvements in respiratory indices with a positive correlation to maximum voluntary ventilation (mvv) improvement. notable significant improvements in continuous aerobic exercises in the intervention group in fvc, fev1 and mvv compared with members’ pre-exercise values (p ≤ 0.01). insignificant differences were found between the 2 groups in relation to pre and post exercise measures. conclusion: appropriate aerobic exercise training can moderately improve lung function by strengthening the muscles of respiratory muscles. therefore, regular physical activity progressively delay the age-related deterioration of lung function and promote healthy aging. key words: fvc, fev1, mvv, bmi, aerobic exercise pp7: schedule 5 drug fluoxetine in dietary/nutritional supplements – storm in a teacup or requirement for improved regulation and accelerated enforcement? gary gabriels1, mike lambert2, pete smith2, lubbe wiesner2 1university of johannesburg, 2university of cape town presenting author e-mail address: gary.gabriels@gmail.com introduction: dietary/ nutritional supplements have become popular in use by a spectrum of different consumers, including the elderly as a ‘new’ market. the elderly numbers have been increasing from 35 million in 2000, to a projected 69 million by 2030. dopamine, serotonin, and epinephrine, neurotransmitter homeostasis is important in the ‘healthy’ physiological continuum of all ages. imbalance in these neurotransmitters, over time, manifest in various ‘disease’ states, such as obsessive compulsive disorder, parkinson’s disease, and schizophrenia. in context, dietary/nutritional supplements may contain contaminants/adulterants that could distort the ‘normal’ equilibrium of neurotransmitters. therefore, for this investigation fluoxetine a schedule 5 (south africa) selective serotonin reuptake inhibitor (ssri) drug was investigated. the extent of fluoxetine as contaminant/adulterant in dietary/nutritional supplements is not widely known. further, fluoxetine prescriber caution for treatment (elderly), are adverse effects, particularly cns effects, such as nervousness, agitation, an xiety or excessive sedation, and insomnia. the aim of this study was to determine whether commercially available dietary/nutritional supplement products contained fluoxetine, even though the manufacturer may not declare this on the product label. methods: a total of 138 dietary/nutritional supplements products formed part of the assessment. the products were laboratory analysed for fluoxetine, as part of an extensive multi-compound ‘screen’, using tandem liquid chromatography mass spectrometry. the concentration of fluoxetine was then estimated via calibration curve standards, which formed part of the extraction and analysis. results: the number of ‘positives’ for the tested products for fluoxetine in the overall cohort was 54%, for south african produced products 67%, and, for imported products, bought in south africa 56%. the median concentration estimate for fluoxetine in the products were, 3.9 µg/g for the overall cohort, 5.2 µg/g for south african produced products, and 20.1 µg/g for imported products, bought in south africa conclusion: the number of products containing fluoxetine should place dietary/ nutritional supplement products under greater scrutiny. further research pertaining to fluoxetine and its’ metabolite, with respect to,(i) product prescribed dosage, (ii) actual dose consumption, and, (iii) the potential link to adverse health consequences physiologically becomes important. rigorous monitoring and vigilance, by health safety authorities, for fluoxetine (metabolite) and other ssri’s in dietary/nutritional supplement products should be mandatory. mailto:adieledube@yahoo.com mailto:gary.gabriels@gmail.com pp8: an integrated investigation into the determinants of putting success: a biomechanical, cognitive and anthropometric approach david goble1, siobhan de lange1, warrick mckinnon 1university of the witwatersrand presenting author e-mail address: davegoble87@gmail.com golf is a game that requires gross motor outputs as well as fine motor control. when putting, accurate decision making, fine motor control and a fluid stroke are thought to be associated with improved accuracy. with more than forty percent of the game played on the putting green, putting accuracy is often the difference between winning and losing. therefore, understanding the mechanisms that promote accuracy of the putt are important to advance training and competition performance. the aim of the current investigation was to identify key biomechanical, physiological, anthropometric and cognitive variables that promote putting accuracy. further aims were to determine if these factors varied by a factor of putting distance. in a cross-sectional laboratory setting, 30 amateur golfers completed ten one meter (short) and ten three meter (long) putts on an artificial putting surface. before putting, participants completed tests for executive function (stroop word-colour interference), visual acuity, hand and eye dominance. additionally, resting heart rate variability and anthropometric data were recorded prior to putting. during the putting stroke, a three-dimensional kinematic analysis system assessed club, hand and arm angles and their associated velocities. in the 20 seconds preceding each putt, heart rate variability was also recorded. correlation analysis (pearson) for short and long putts compared putting accuracy with each dependent variable. the study is still in the data collection phase and results will be collated and presented at the conference in october. pp9: the effectiveness of the south african sport academy system towards high performance sport development shaundre jacobs1, ranel venter1, veerle de bosscher2, jeroen scheerders3 1stellenbosch university, 2vrije universiteit brussel, 3ku leuven university presenting author e-mail address: sdjacobs@sun.ac.za in most countries with high success rates in olympic sports, high performance sport policies have shifted towards becoming more systematic and scientific, encouraging an institutionalist design of elite sport. in recent years, there has been growing interest from both researchers and policy makers alike, in determining international success of elite sport due to this evident shift worldwide. sport operates in an open system that is significantly influenced by social, cultural and economic conditions of a country, which may be perceived as confounding factors influencing each nation’s international sporting success separately. in literature, an elite sport development system is often a description of established practises with little regard for effectiveness, or its operations and relationships within its specific environment. this study investigates elite sport success dimensions, contextual factors and power relationships between stakeholders in south african sport. this project will apply the evaluation of sport policy effectiveness and advance current literature by analyzing the pragmatic approach of a theoretical framework. the sport policies leading to international success (spliss) model, which is a validated multi-dimensional comprehensive framework linking sport policy to success, is paralleled to this study. the convergent parallel mixed methods design is used to collect data at multiple points of the inputthroughput-output phases. the policy analysis results in phase 1 revealed 53 success dimensions, which ultimately is the foundation of high performance sport in south africa. the theories guiding the methods in phase 2 will be the systems theory, resources dependence theory and inter organisational relationships theory. in conclusion, this study intends to systematically address all factors aforementioned to identify how these aspects influence the elite sport policy effectiveness in south africa as developing country. this will describe the environment of elite sport as a whole. key words: high performance sport, sport policy, effectiveness pp10: participation likelihood assessment tool for wheelchair basketball bhekuzulu khumalo1, prof. johan van heerden2, thomas k. skalko, ph.d., lrt/ctrs, fdrt3 1sports science lecturer, 2school academic leader : research school of health sciences ukzn, 3east carolina university professor, college of health and human performance cell: 252-347-6840 presenting author e-mail address: bkhumalo46@gmail.com introduction: enhancing participation in wheelchair basketball (wb) needs a proactive approach, it is important that administration seeks objective information on potential participants for the sport. purpose: the development of a tool to be used as a practical and inexpensive means of gathering information on the probability of one being a wb player. methods: using snowballing to identify research contributors, 137 respondents (106 participants and 31 non-participants) comprising 95 males and 42 females, ranging in age, from 19 to 58 years, were surveyed utilising three questionnaires: (a) perceived accessibility to facilities questionnaire (pafq), (b) exercise benefits scale (ebs) and (c) barriers to exercise scale (btes). the non-parametric wilcoxon rank-sum (mann whitney u) test, was used to establish if there were any areas of significant (p ≤ 0.05) differences in perception between participants and nonparticipants. discriminant function analysis was performed as a multivariate test of differences between participants and non-participants and predictive discriminant analysis was used to determine the minimum number of dimensions needed to describe these differences. results: a 19 item linkert scale [“1=strongly disagree to 5=strongly agree”] questionnaire, was developed. conclusions: within limited resources, an acceptable concise and expedient screening instrument (the plat wb) was developed, which could be refined further to counter potential limitations. key words: analysis, perception, participation, restrictions pp11: 20.7% cyclists entering a 109km race report risk factors for cvd, and 3.7% report existing cvd: pre-participation screening among 22 650 cyclists safer cycling jannelene killops1, martin schwellnus1 2 3, christina janse van rensburg1, sonja swanevelder4 1sport, exercise medicine and lifestyle institute (semli) & section sports medicine, faculty of health sciences, university of pretoria, south africa, 2international olympic committee (ioc) research centre, south africa, 3emeritus professor, faculty of health sciences, university of cape town, south africa, 4biostatistics unit, south african medical research council presenting author e-mail address: killops@iafrica.com mailto:davegoble87@gmail.com mailto:sdjacobs@sun.ac.za mailto:bkhumalo46@gmail.com mailto:killops@iafrica.com introduction: european guidelines for the pre-participation screening of masters and leisure athletes are available to identify which athletes who should undergo a medical assessment prior to moderateto high-intensity sports participation. these guidelines follow a pre-exercise screening process for risk factors of cardiovascular disease (cvd), other chronic conditions, and medication use. the purpose of this study is to determine the prevalence of cvd, risk factors for cvd, presence of other chronic diseases, and other risk factors for medical complications in cyclists participating in a community based mass participation cycling race using current european guidelines methods: this is a cross-sectional study on entrants that participated in the 2016 cape town cycle tour (109km). all race entrants (n=37 425) were required to complete an online pre-race medical screening questionnaire. we determined the crude (unadjusted) prevalence (% with 95% ci) of history of existing cvd, risk factors for cvd, history of chronic disease in other organ systems, and other risk factors for medical complications during moderateto high-intensity sports participation in 22 560 consenting participants (60.3%). results: 3.7% (3.5-4.0) cyclists reported existing cvd, and 1.1% (0.1-1.2) reported existing symptoms of cvd. risk factors for cvd were present in 20.7% (20.2-21.3) cyclists and the prevalence of a history of chronic diseases in other organ systems was as follows: respiratory (11.4%; 11.0-11.8), gastrointestinal (5.4%; 5.15.7), nervous system (3.4%; 3.3-3.8), metabolic/hormonal (3.8%; 3.6-4.1), kidney/bladder disease (3.0%; 2.8-3.2), blood/immune disease (1.4%; 1.2-1.5), cancer (3.2%; 3.0-3.5), allergies (13.6%; 13.1-14.0). the prevalence of other possible risk factors for medical complications was as follows: chronic prescription medication use (25.3%; 24.7-25.8), use of medication before or during races (8.7%; 8.3-9.0) and a history of collapse (0.8%; 0.7-0.9). conclusion: risk factors for cvd were reported by > 20% cyclists entering a community based mass participation cycling race, while 3.7% report existing cvd, and 1 in 4 use prescription medication. we suggest that further research to determine if pre-race medical screening, using the european guidelines, together with educational intervention can reduce the risk of medical complications during community based mass participation cycling events. pp12: relationship of aslr and functional movement deficiencies in physically active individuals with and without low back pain zarko krkeljas1, dimitrije kovac1 2 1stellenbosch university, 2fitness medico clinic presenting author e-mail address: zarko@sun.ac.za over 80% percent of people experience low back pain (lbp), of which 85% go undiagnosed and remain characterized as non-specific lbp. consequently, researchers are proposing a multimodal approach to the assessment and management of the lbp, and classification of patients based on the functional movement impairment. active straight leg raise (aslr) is widely used diagnostic tests for lbp, but there is a lack of evidence of association with other clinical parameters, and functional analyses used in evaluation of lbp. hence, the primary aim of this study is to investigate association of aslr test with the movement deficiencies in muscles and joints responsible for lumbo-pelvic stability in populations with and without low back pain. 100 physically active participants with (n=50) and without lbp (n=50) volunteered for the study. one-way anova was used to examine for potential differences between two groups, and multiple correspondence analysis (mca) to examine the pattern of relationships between the measured variables. participants without pain had significantly higher aslr score (p < 0.001), demonstrated better hamstring flexibility (p < 0.001) and better gluteal activation pattern (p < 0.01). on the other hand, participants with lbp had greater incidence of pelvic rotation during knee flexion, and hip internal rotation, relative to participants without lbp (p < 0.001). results also demonstrate that participants with pain scored largely 1 on the aslr which was also associated with hamstring tightness, calf tightness, limited trunk flexion, hypomobility of the trunk, and posterior pelvic tilt. these findings indicate a strong association of low back pain with functional movement impairment and weakness in movement motor control. aslr test should be used conjunction with other functional evolution tests to isolate the cause of lbp in physically active individuals. pp13: the impact of barefoot versus shod running on lower limb gait cycle pattern among recreational club runners in durban, kwazulunatal siyabonga henry kunene1, calvin shipley2, candice rommers2, catherine scruton2, lusanda ndlovu2, saleha vawda2, zakkiyya latib2 1physiotherapy department, university of kwazulu-natal, durban, kwazulu-natal province, south africa. 2physiotherapy department, university of kwazulu-natal, south africa. presenting author e-mail address: siyabonga.kunene@wits.ac.za introduction: despite health benefits that come with running, injuries are common with prevalence ranging between 18.2% and 92.4% worldwide. differences in gait patterns between barefoot and shod running, can determine traits that could lead to running injuries. the aim was to assess and compare lower limb gait cycle patterns between barefoot and shod running among runners. methods: an experimental same-subject study design was used. the study population consisted of male and female adult recreational runners who were injury free from a running club in durban. a convenience sampling method was used and 14 participants were recruited. the study was conducted in the physiotherapy performance laboratory at the university of kwazulu-natal. a woodway desmo treadmill and kinepro gait analysis system were used. descriptive & inferential statistics were analysed using microsoft excel and intercooled stata. results: participants included a greater percentage of females (57.1%, n = 8) than males (42.9%, n = 6). the mean population age was 38.57. a significant difference (p < 0.0009) between barefoot cadence (177.9236steps/min) and shod cadence (171.9445steps/min) was observed. right (0.261s) and left (0.257s) barefoot stand phase was shorter than right (0.273s) and left (0.270s) shod stand phase. right barefoot swing phase exhibited less significant (0.420s) results when compared to right shod swing phase (0.427s), whereas left barefoot swing phase was quicker (0.416s) than left shod swing phase (0.432s). significant differences between barefoot and shod stand (p < 0.009) and swing (p < 0.040) phase symmetry occurred. conclusion: a considerable difference was found between barefoot and shod running gait cycle patterns among participants. this difference may play a role in prevention of running related injuries. keywords: barefoot running, shod running, gait cycle pattern, same-subject study design pp14: lifestyle risk profiles of primary school teachers: a school-based professional development intervention daga makaza1, rowena naidoo1 1university of kwazulu-natal, discipline of biokinetics, exercise and leisure sciences; durban, south africa presenting author e-mail address: dmakaza@gmail.com mailto:zarko@sun.ac.za mailto:siyabonga.kunene@wits.ac.za mailto:dmakaza@gmail.com introduction: usually, teacher’s habits and lifestyle at school are well observed by learners. if teachers are free from risk factors such as physical inactivity, tobacco use and alcohol abuse; only then can positive role modelling transmit to learners. the purpose of this study was to evaluate the impact of a professional development intervention on personal profile lifestyle risk factors relating to physical activity, smoking and alcohol consumption of primary school teachers in zimbabwe. methods: a convenient sample of 28 primary school physical education teachers with a mean age of 37.9(±6.7) years and mean teaching experience of 9.1(±3.7) years participated in the study. the teachers were randomly allocated to an intervention group (n=15) and control group (n=13). teachers completed a personal lifestyle risk questionnaire pre and post-intervention. the intervention was designed to introduce content, assessment methods, teaching material improvisation and teaching methods within the existing school curriculum. results: results showed that there was a statistically significant difference in post-intervention measures between the intervention and control groups. this included frequency of vigorous exercise (p0.005); time taken per day performing moderate physical activity (p0.005), number of days per week walked for at least 10 minutes (p=0.021), total time spent walking (p=0.047), sitting time (p0.005) after correcting for the preintervention measures. after using the wilcoxon signed rank test on the intervention and control groups separately, the intervention group showed a significant difference in walking pace post-intervention (p =0.008). all teachers did not smoke. there was no effect on alcohol intake, physical and mental health post-intervention. conclusion: a school-based professional development intervention can improve the lifestyle risk profile of primary school teachers. pp15: health related risk behaviors amongst university residence student loyiso maqina1, nevel neveling 1university of zulu land presenting author e-mail address: loyiso.maqina@gmail.com background / context: south africa suffers from a double burden of both communicable and non-communicable diseases. the youth risk behaviour survey (yrbs) is designed to increase understanding and awareness of health-related behaviours that lead to high mortality and morbidity rates among the youth. there are very limited surveys conducted on university students in south africa. aim / purpose: the study aims to improve the understanding of risky behaviours that may lead to the development of communicable and noncommunicable diseases amongst university residence students. method / what was done: a qualitative study performed amongst university residence students at 13 different university and two private residences. this student risk behaviours survey was conducted using the yrbs questionnaire, with physical activity profiling done through the ipaq. results and discussion: seventy eight percent of students reported having had sex, of which 34.1% reported an initiation age of 17 years of age and above. amongst the students who were sexually active, 22% had sex with more than 2 people whilst 7.3% of students stated that they had had sex with more than 3 people in the last 3 months. alarmingly 42.5% of students reported to have had sex under the influence of alcohol of which only 52% of them reported using a condom. amongst 63.4% students believed that being faithful to one partner would protect them from contracting hiv/aids, meanwhile 4.9% believed that traditional healers are able protect them against hiv/aids. thirty percent of students reported not having engaged in physical activity for more than 60 minutes. ipaq revealed that 52% of the students scored low with regards to physical activity. conclusion / take home message: the findings suggest there is a need for more research amongst university residence students. these studies will assist in updating data on priority risk behaviours which will aid in the understanding of student risk profiles and ultimately form part an intervention strategy. pp16: the effect of six weeks taekwondo and strength training program on body composition and physiological parameters in university taekwondo athletes musa mathunjwa1, mlondi shozi1 1university of zululand presenting author e-mail address: mlmathunjwa@gmail.com introduction: the aim of the study was to investigate the effects of 6 weeks taekwondo training on body composition and physiological parameters in university taekwondo athletes. methods: fifteen (n=15) healthy taekwondo athletes with age range of 18 25 years participated in the study. taekwondo and resistance training was performed in 6-weeks, 5 times per week, 1hr morning and 1hr afternoon per day. the participants were pre and post-tested on body composition (weight, height, ss, bmi, skinfolds, and hip to waist ratio) and physiological parameters (blood pressure, heart rate, and vo2max). data was analysed using paired t test for independent samples. results: tkd showed a significant improvement (p0.05). conclusion: taekwondo training was effective to change many body composition and physiological variables. although this training can be useful for improving performance and health status of individuals, but complimentary habits such as nutritional interventions are necessary. keywords: taekwondo, physiological parameters, body composition pp17: association between sport participation, body composition, physical fitness and social correlates among adolescents: the pahl study andries monyeki1, agat glapa1 1physical activity, sport and recreation focus area presenting author e-mail address: andries.monyeki@nwu.ac.za background: paucity exists about studies on social support, body composition and physical fitness in south african adolescents. the aim of this study was to examine whether sport participation in organizes sports is related to body composition, physical fitness and social correlates. methods: a cross-sectional data on 238 adolescents (90 boys and 148 girls) with the mean age of 14.9±0.8 years, who were participating in the physical activity and heath longitudinal study (pahls), were collected. the participants were divided into two groups: ‘sport participation’ (sp) group and ‘non-sport participation’ (nsp) group. height, weight, body mass index, percentage of body fat and skinfolds were assessed according to standard procedures. the eurofit battery of tests was used to assess standing broad jump (sbj), bent arm hang (bah), sit-ups (sup), sit and mailto:loyiso.maqina@gmail.com mailto:mlmathunjwa@gmail.com mailto:andries.monyeki@nwu.ac.za reach (sar) and predicted vo2max. social support for physical activity (sspa) questionnaire was used to obtain information on social correlates for physical activity. results: the results show that nsp group significantly (p=0.011) had high sum of skinfolds (sskf) (25.00±12.40; 33.06±17.74) and %bf (20.00±9.67; 25.63±11.76) as compared to the sp. in terms of physical fitness, sp significantly outperformed the nsp in sbj (165.25 ± 28.84; 146.23 ± 20.79, p=0.000), sup (29.19±10.51; 22.57±10.08, p=0.003) and vo2max (34.25±8.11; 27.29±6.42, p=0.000), with boys were better than the girls. significant gender different was also observed for the social support (19.95±3.16; 17.04 ± 3.60, p=0.000) with sp been more advantageous than the nsp, especially in boys. generally, fatness measures were negatively associated with sbj, bah, vo2max. sar was positively associated with %bf (β= 0.17, p=0.015) in sp. while in nsp, sar was negatively associated with bmi (β= -0.49, p=0.009) and skf (β=0.40, p=0.036). conclusion: it can be concluded that adolescents who have had social support and participated in sports performed better in most of the physical fitness. given the public health benefits associated with fitness, advocacy regarding the importance of ‘social support’ benefits towards physical fitness are urgently needed. pp18: exercise as conservative treatment for shoulder impingement syndrome: a systematic review sarah moss1, leanri van zyl1, melainie cameron1 2, erna bruwer1 2 1north-west university, phasrec, north-west university, 2university of the sunshine coast, maroochadoor, australia presenting author e-mail address: hanlie.moss@nwu.ac.za background: the aim of this systematic review is to evaluate the effectiveness of home-based or supervised exercise as treatment modality for persons with sis. methods: electronic searches were performed in cochrane central register of controlled trials (central), ebsco host, science direct, scopus, pubmed and web of science. rct’s, involving male and/or female adults ˃18 years, with any history of sis were included. studies had to evaluate any mode of exercise as treatment modality or exercise in combination with other conservative interventions for treating sis – only if the results of exercise treatment were provided separate from results for other modalities used. two authors independently identified potential trials for inclusion, assessed methodological quality and extracted data. we calculated the md, smd and an overall effect size of 95% ci using review manager 5. results: six studies (n=475) were included (intervention period 3-12 weeks) and pooled according to the same control group for analyses. outcomes of interest were pain at rest, pain during movement, shoulder rom, function and patient satisfaction. one study reported statistically significant improvement favouring the exercise group for pain at rest (md -1.90; 95% ci -3.36 to -0.44; p=0.01) and pain during movement (smd -0.81; 95% ci -1.18 to -0.44; p0.0001). no significant improvements were reported among groups for the remaining studies. shoulder rom was assessed and one study reported statistically significant improvement for medial rotation (md 9.70; 95% ci 2.34 to 17.06; p=0.010) and the remaining rom measurements showed no significant difference among groups. the results for one study were inconclusive and another study showed no significant difference in active rom between groups. studies also indicated statistically significant improvement in laborious function (smd -0.66; 95% ci -1.02 to -0.29; p=0.0004). two studies showed improvement in function for the exercise group but were not significant. one study showed statistically significant improvement for patient satisfaction for the exercise group (md 1.20; 95% ci 0.24 to 2.16; p=0.01). conclusion: the available evidence was too sparse and the variability of exercise prescription in relation to the fitt principles too broad to draw conclusions about the effect of specific exercise regimes in treating sis. pp19: the carry-over effect of an aquatic-based intervention in children with cerebral palsy rowena naidoo1, samantha ballington 1university of kwazulu-natal presenting author e-mail address: naidoor3@ukzn.ac.za background: cerebral palsy (cp) is the most common motor disability in childhood. children with cp are more likely to have decreased physical activity levels than their peers, thus they are at risk for negative health implications. however, there is a belief that aquatic exercise can be used for the improvement of the level of fitness among children with cp. the aim of this study was to determine the carry-over effect of an aquatic-based programme (postural control and balance) on land (walking, running and jumping) in children with cp preand post-intervention. methods: the study was a pretest–post-test randomised groups, crossover design. ten (n=10) children diagnosed with cp were divided into intervention group (n=5) or a control (n=5) group. the intervention group participated in two 30 minute sessions a week, while the control group continued with activities as per normal. preand post-intervention testing was conducted using the gross motor function measure. the tenpoint programme of the halliwick concept was used. results: results demonstrated that the aquatic therapy had a significant effect on the gross motor function measure score. the aquatic-based group showed increased growth following the intervention compared to the control group (z= -2.803, p= 0.005). furthermore, the aquatic-based therapy improved the average score for the gross motor function measure, post-intervention. conclusion: in conclusion, an 8-week aquatic-based intervention produced greater gains in gross motor function in children with cerebral palsy, hence producing a significant carry-over effect on land. pp20: growth pattern profile and motor performance of basic school children in sub-urban population in nigeria rafiu olaoluwa okuneye1, bilikisu bidemi idowu (ph.d)1, chukwu emeka ugwuegede1 1lagos state university presenting author e-mail address: laolurafiu@yahoo.co.uk growth profile is a significant indicator of pattern of developmental variables in children. the purpose of this study is to collage profile of growth of basic school age children (6-15years) on height, weight, body mass index (bmi), body girths and length. it also aimed at assessing motor performance of the children at their physical growth status. values obtained would indicate nutritional status, health status and serve as parameter for identification and recruitment of potential athletes. participants for the study were drawn from public basic schools (primary 1 to junior secondary school class 3) located at sub-urban areas in nigeria. a multi-stage sampling technique was adopted in selecting a total of 1,300 boys and girls for the study. measurement of body parameters and performance tests followed the guidelines of ichpher.sd children/youth fitness test manual (2012) and isak (2001). mean, sd, range as well as percent count were analysed for each variable. findings show that high mailto:hanlie.moss@nwu.ac.za mailto:naidoor3@ukzn.ac.za mailto:laolurafiu@yahoo.co.uk percentage of the children are underweight for their ages and it is more prevalent in boys. high percentage of them have low height for their ages. high percentage of them fall within normal range of bmi for their ages. there is sequential increase in both girths and length of the body parts with increasing ages though at a rate far below international standard. children performed better in motor skill requiring repetition but poorly in those that require power. in conclusion, basic school children in sub-urban areas in nigeria are stunted in growth with low body weight, they need nutritional support. however the children have healthy weight for their height; they are free from problems associated with excess body fat. the category of the children could be focused upon for recruitment into endurance sports training programmes. keywords: growth pattern; motor performance; basic school children; sub-urban population. pp21: pathways of fluid leakage from the retrocalcaneal bursa to the achilles tendon a radiologic study with implications for brusal steroid injections przemysław pękala1, brandon michael henry1, paweł kopacz2, ewa mizia1 1department of anatomy, jagiellonian univeristy medical college, 2department of forensic medicine, jagiellonian univeristy medical college presenting author e-mail address: pekala.pa@gmail.com introduction: the retrocalcaneal bursa (rb) lies close to the achilles tendon (at) insertion. its main role is to reduce at friction during movement. inflammation of this structure, retrocalcaneal bursitis, is a common clinical problem among athletes and is treated with corticosteroid injections. however, there are several reports suggesting that such injections increase the risk of at rupture. the aim of this study was to determine whether fluids injected into the rb can spread outside of its anatomical structure. methods: the study was conducted on 10 fresh-frozen cadaveric specimens. each specimens’ rb was injected (5 under ultrasound guidance, 5 without ultrasound guidance) with 2ml radiological dye (iopromide). then, four radiographs of each specimen were taken at subsequent time points: immediately after injection, 5 minutes, 30 minutes and 60 minutes after injection. all radiographs were digitally analyzed using imagej software. results: in all injected specimens, the dye injected into the rb spread to the at. dye spread was most extensive in two specimens that were injected without ultrasound guidance. the mean expansion of the dye in these two specimens was 4.1 cm superiorly covering a total area of 6.3 cm2 one hour post-injection. in the other eight specimens, the dye diffused on average 1.0 cm in the superior direction covering a total area of 1.8cm2. conclusions: this radiological study confirms the existence of anatomical connections between the at and the rb. moreover, weak zones with especially high leakage (antero-inferior portion of the at) were observed. physicians performing injections into the rb should be cautious and be aware that fluids injected into the rb structure can spread outside of it and into the at. we strongly recommend employing radiological guidance during rb injections. pp22: a comparison between the cardiorespiratory responses of a non-motorized and motorized treadmill protocol. jana storm1, dr. yolandi willemse1, dr. martinique sparks1 1north-west university presenting author e-mail address: 21468370@nwu.ac.za objectives: to determine which running modality, the motorized treadmill (mt) or the curve non-motorized treadmill (nmt), will allow elite male university-level distance runners to attain the highest cardiorespiratory responses. design: a once-off cross-sectional design using elite male university-level distance runners. methods: two gxt protocols were used to compare the above-mentioned running modalities the adapted incremental speed protocol (aisp), performed on a mt, and the adapted non-motorized incremental speed protocol (anmip), performed on a curve nmt. both protocols started at a speed of 10 km/h, where after the aisp continuously increased by 1 km/h speed increments each 1 minute, and the anmip increased by 2 km/h speed increments every 2 minutes until exhaustion. cardiorespiratory responses were recorded throughout the test from which the intensity markers, the ventilatory threshold (vt) and the respiratory compensation point (rcp) were determined. results: the maximal aerobic capacity (vo2 max) value of the anmip exceeded that of the aisp significantly (p0.05; d=2.61; r=0.89) and attained these values within a significantly (p0.5) shorter time frame (8.31 ± 0.87 vs. 11.42 ± 1.19 min). the percentage of vo2 max where vt and rcp were attained, was significantly higher (p0.5) on the anmip (84.1 ± 4.3 vs. 97.2 ± 2.4%) compared to the aisp (75.7 ± 7.8 vs. 93.3 ± 3.9%). conclusion: the anmip is perceived as substantially more difficult, both physiologically and psychologically, compared to the aisp. the vt and rcp intensity markers attained by the anmip, are not practical for exercise prescription. pp23: comprehensive cardiac rehabilitation and quality of life in coronary artery bypass graft patients lynn van rooy1, yoga coopoo2 1lecturer, 2professor presenting author e-mail address: lynnvr@uj.ac.za the overall success of coronary artery bypass graft (cabg) surgery is much dependent on the postoperative rehabilitation. cardiac rehabilitation (cr) programmes should be comprehensive and multifactorial to enhance education and quality of life of the patient. this was a quasi-experimental and longitudinal intervention study to which 18 patients who had undergone cabg surgery were referred. two questionnaires were administered and patients participated in a 12 week exercise programme. significant improvements were noted in waist circumference (99.7±8.3 to 97.8±8.8; p=0.042), body fat percentage (22.7±5.3 to 20.5±4.9; p=0.000), resting systolic blood pressure (125.7±13.7 to 119.7±8.9; p=0.000), stairs climbed (3.6±3.5 to 5.9±4.4; p=0.003), duration of exercise per week (329±383.7 to 527±482.7; p=0.001), kilocalories expended per session (827±765 to 1173±699; p=0.001), kilocalories expended per week (2550±1858 to 3996±1849; p=0.000), chair sit-and-reach (0.7±3.4 to 1.3±3.4; p=0.001), up and go (6.0±1.3 to 5.1±1.2; p=0.002), chair stand (13.4±2.3 to 16.2±2.3; p=0.000), maximum workload (82±23.0 to 110±29.4; p=0.000), maximum duration (08:35±02:41 to 11:57±03:51; p=0.000), physical component score (38.8±6.1 to 52.1±4.2; p=0.000) and mental component score (49.5±8.5 to 56.9±3.1; p=0.002). it can be concluded that cr encompassing lifestyle intervention, education and psychological support results in a faster reco very of health and desired performance of the cabg patient. mailto:pekala.pa@gmail.com mailto:21468370@nwu.ac.za mailto:lynnvr@uj.ac.za pp24: the prevalence, risk factors predicting injury and severity of injuries sustained during competition in professional mixed martial arts in africa santa-marie venter1, dina c janse van rensburg1, catharina grant1, lizelle fletcher2 1up sports medicine, 2up statistics presenting author e-mail address: drventer@yahoo.com background: professional mixed martial arts (mma) has gained international popularity. no african based studies have reported the prevalence or severity of injuries, risk factors associated with injuries or return-to-play (rtp) time. objective: to determine the prevalence of injuries and associated risk factors, as well as severity of injuries sustained by professional male mma athletes competing at extreme fighting championships africa (efc africa) from 2010 to 2014. design: results from this prospective cohort study were compared to a similar study done in the united states of america (usa). an injury was defined as any damage to an athlete’s body that needed the attention of the ringside physician. setting: permission to do the study and the medical records of all professional events (2010 – 2014) were obtained from efc africa. participants: data were obtained from 173 male competitors aged 18 to 44 years, participating in 300 professional mma fights. methods: statistical analyses included descriptive statistics and a stepwise logistic regression. odds of an injury were predicted with six independent variables: fight outcome, age, weight division, number of fights, injuries in preceding fight and years of fighter experience. results: head, face and neck injuries were most common (22%), followed by traumatic brain injuries (knock-outs) (6%). losing a fight was a significant predictor of injury when using a stepwise logistic regression model (p=0.040). the odds ratio indicated that preceding fight injury almost doubled the risk of injury in the following fight (or 1.91; p= 0.163). traumatic brain injuries (tbis) in this study of african based competitions (6%) were substantially higher than reported in the american study (1.8%). conclusion: head, neck and face injuries are common in african fighters. the high rate of tbis in african competition compared to the usa study is concerning. this could reflect superior refereeing in the usa group, as fights may be ended sooner by stoppage. further investigation of injury trends and preventative measures should be studied to reduce the incidence of injuries during african games. mailto:drventer@yahoo.com abstract index sasma 2017 abstracts print ready (revised cdp 17 oct) regular participation in physical exercise or sport is popular due to the numerous health benefits it offers to the individual. 1 however, these potential benefits need to be offset against the magnitude of risk of injury that participating in the activity may present to the individual. the risk/benefit ratio varies depending on the type of activity. 1 in terms of major male-dominated sports, rugby union presents a high risk of overall injury to the player – greater than that of cricket, soccer or even ice hockey. 2 the high incidence of injury in rugby is related to the nature of the game – a field-based team sport that involves multiple contact situations over the 80 minutes of play. 3 considering the popularity of the sport, with an estimated 92 countries participating worldwide, this injury risk presents a significant global issue. 3 from the inception of the game of rugby union, which is speculated to have been between the start of the 1600s and the mid 1800s, the game has been regarded as a violent sport and the formation of the rugby football union in 1871 was necessitated, in part, by the need for laws to reduce this violence. 4 the laws of rugby union have developed exponentially in both number and complexity from these amateur beginnings to the game’s professional present. subsequent law development has not only had the motive of reducing unnecessary injury, 5 but also to distinguish rugby union from other codes of rugby and from ‘simpler’ games that were thought to be for the common working classes. 4 despite this exclusivity, rugby union, like all other sports, was forced to compete with other sports for spectators. 4 as a result, from as early as the 1876 1877 season, in which the rugby football union (rfu) reduced the number of players on the field from 300 to 30, there have been numerous examples of law changes that were brought about to enhance spectator gratification. the result – a faster, more open, running game – is believed to be associated with an increased risk of injury due to the greater speed and frequency of physical contacts. 6 of all sports injuries, those with catastrophic outcomes are the most life-altering, both for the sufferer and for their immediate family and friends. while media reports often closely associate rugby union with catastrophic injuries, 7 the actual risk of sustaining these types of injuries while playing rugby is low in comparison to other sports (diving and horse-riding) and even everyday activities (driving or walking to work). 8 despite this contextual perspective, the consequences of catastrophic injuries are such that even one case a year as a result of participating in rugby is one case too many. in south africa, the stories of the tragic deaths of chris burger and petro jackson, as well as the many rugby players supported by their memorial fund (chris burger petro jackson players’ fund), bears testament to this statement. 9 owing to the high risk of injury, either in incidence or severity, that rugby union poses to the player, epidemiological researchers have been investigating this sport extensively since 1954. 10 researchers in new zealand not only accurately described the incidence of injuries in rugby, but also developed and evaluated an injury prevention programme that sought to reduce the incidence of injury. 11 the programme, known as rugbysmart, chose to educate coaches and referees about best practices to reduce the risk of injury, assuming that these key stakeholders would disseminate their knowledge and behaviour to their players. in the evaluation of the programme, 12 rugbysmart was found to be effective not only in reducing the incidence of both general and catastrophic injury, but also in improving rugby players’ knowledge and behaviour with regards to injury risk factors over the course of 5 years. the sport of rugby union is also particularly popular in south africa, with an estimated 400 000 500 000 players nationwide. 13 despite the high level of participation, there have been few wellperformed prospective epidemiological studies on rugby in south africa. of concern are the estimates of catastrophic injury that are available since 2001, largely as a result of the chris burger petro jackson player’s fund, which suggest an average of 22 catastrophic injuries per annum in south africa. 13 this concern about catastrophic injuries resulted in the rugbysmart intervention programme being adapted, with permission, for the south african context. the south african programme, boksmart, was launched in july 2009. despite vast differences between new zealand and south africa in the context of implementation of this programme, more than 25 000 coaches and referees have already been educated about the principles of safety in rugby in south africa. the next important step is to determine whether the knowledge of the coaches and referees who have undergone training in south africa translates into behaviour that reduces the incidence and severity of rugby-related injuries. references 1. van mechelen w, hlobil h, kemper hc. incidence, severity, aetiology and prevention of sports injuries. a review of concepts. sports med 1992;14(2):82-99. 2. fuller c, drawer s. the application of risk management in sport. sports med 2004;34(6):349-356. 3. duthie g, pyne d, hooper s. applied physiology and game analysis of rugby union. sports med 2003;33(13):973-991. 4. richards h. a game for hooligans. the history of rugby union. edinburgh: mainstrean publishing company, 2007. 5. burry hc, calcinai cj. the need to make rugby safer. br med j (clin res ed) 1988;296(6616):149-150. 6. noakes td, du plessis m. rugby without risk. a practical guide to the prevention and treatment of rugby injuries. pretoria: van schaik, 1996. commentary the introduction of an international model to reduce injuries in rugby union in south africa correspondence: james brown department of human biology university of cape town tel: 021 650-4572 fax:021 686-7530 e-mail: james.brown@uct.ac.za james craig brown (msc) mrc/uct research unit for exercise science and sports medicine, department of human biology, university of cape town 62 sajsm vol 23 no. 2 2011 7. quarrie kl, cantu rc, chalmers dj. rugby union injuries to the cervical spine and spinal cord. sports med 2002;32(10):633-653. 8. fuller cw. catastrophic injury in rugby union: is the level of risk acceptable? sports med 2008;38(12):975-986. 9. tebbutt p. samaritan of south african rugby. sun press, 2010. 10. o’connell tc. rugby football injuries and their prevention; a review of 600 cases. j ir med assoc 1954;34(199):20-26. 11. quarrie kl. rugbysmart: the development, delivery and evaluation of a nationwide sports injury prevention programme. auckland university of technology, 2008. 12. gianotti sm, quarrie kl, hume pa. evaluation of rugbysmart: a rugby union community injury prevention programme. j sci med sport 2009;12(3):371-375. 13. sa rugby website, 2009. boksmart national rugby safety program. available at: http://www.sarugby.co.za/boksmart/default.aspx (accessed 16 march 2011). sajsm vol 23 no. 2 2011 63 sajsm vol 24 no. 1 2012 25 commentary chronic, non-communicable diseases (ncds) account for more than two-thirds of global mortality, at least 50% of which is preventable on the basis of modifiable lifestyle behaviours. in the wake of the un global summit on ncds, the world health organization produced a discussion paper that emphasised the need for a global monitoring framework and voluntary global targets for the prevention and control of ncds.1 the who discussion paper presents 10 suggested voluntary targets including the reduction in deaths due to ncds, cardiovascular disease and diabetes, an overall reduction in blood pressure and obesity, as well as reduced smoking, alcohol and dietary salt intake, increased screening for cervical cancer and the elimination of trans-fats from the food supply. physical activity is notable by its absence from this critical list of voluntary global targets for preventing and controlling ncds. physical activity as a global health indicator? in a recent blog post, johanna ralston, the ceo of the world heart federation, commented on this omission of physical activity from the who’s ‘top 10’. ‘physical inactivity is noticeably absent from the most recent iteration of who proposed targets, and the question is, if we are to include physical activity in the monitoring framework, how can governments effectively monitor physical activity levels? how can we ensure accurate data?’2 she goes on to remind us that ‘what gets measured gets done … and that the controversy concerning how many and which targets will be presented at the world health assembly has not yet been resolved’. the major concern regarding the inclusion of physical activity has been the perception that there is no accurate and reliable indicator for physical activity at a population level. in response to this post, professor fiona bull, chair of global advocacy for physical activity (gapa), from the university of western australia, highlighted the work on the development and validation of self-report measures for physical activity, spanning the last decade, involving academics all over the world. such work includes the international physical activity questionnaire (ipaq) and the global physical activity questionnaire (gpaq). bull reminds us that ‘both instruments have been tested in a large number of countries – including those from low and middle-income settings (lmics)’. further, both instruments measure activity in multiple domains, such as work, transport and leisure, which is important, as work and transport patterns are rapidly changing in lmics. professor bull further points out that ‘this characteristic is particularly useful for monitoring and influencing policy and practice – particularly in relation to urban design and development’.2 these instruments have been used in over 130 countries, including south africa, and it is through this type of surveillance that we have been able to characterise the burden associated with physical inactivity.3 finally, professor bull emphasises ‘the need to defend and advocate for the importance of including physical activity as a global indicator … and that gapa (global advocacy for physical activity, a council of the international society of physical activity and health) has suggested the following voluntar y target for physical activity, which is consistent with the policy context and scientific evidence: ‘target: a 10% relative reduction in the prevalence of insufficient physical activity in adults (defined as less than 150 minutes of moderate physical activity per week or equivalent). ‘indicator: age-standardized prevalence of insufficient physical activity in adults (defined as less than 150 minutes of moderate physical activity per week or equivalent)’.2 moreover, there has been a tremendous amount of work done over the past 2 years, evaluating ‘best practice’ for population and community-based interventions for increasing physical activity participation, and ‘clear actions’ which may be adopted and implemented by member states. these have been summarised in a recent publication titled seven investments that work for physical activity, available from the gapa website (http://www.globalpa.org. uk/investments/).4 exercise as a ‘vital sign’ in a recent editorial for the british journal of sports medicine, robert e sallis, chairman of the exercise is medicine advisory board, argued that it is as important for physicians to ask a patient about their exercise habits as it is to take their blood pressure.5 in his experience in managed healthcare, every patient has their exercise ‘vital sign’ taken. they are asked two simple questions: ‘on average, how many days/week do you engage in at least some moderate activity?’ and ‘on those days, on average, how many minutes are you active at this level?’. sallis acknowledges that accuracy of self-report for some patients may not be ideal, but that doctors and health practitioners have an ethical obligation to measure this ‘vital sign’ and to counsel their patients on increasing daily levels of physical activity. think globally, act locally so, we are standing on the edge of a precipice, where ncds have received global recognition, the prevention and management of which is critical to global well-being. however, at the same time, physical activity is again sidelined, despite over 2 decades of unequivocal evidence linking inactivity to morbidity and mortality, despite having validated global self-report instruments for surveillance of physical activity, and despite having a wealth of information concerning evidence-based practice for ‘what works’ at a population and community level to increase participation in physical activity. physical activity as a global risk factor for non-communicable diseases: time for action, what, why, when, who and how? estelle v lambert (bs, ms, phd) uct/mrc research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town correspondence to: estelle lambert (vicki.lambert@uct.ac.za) 26 sajsm vol 24 no. 1 2012 what can we do? the time for action is now, to ‘think globally and act locally!’ south africa has the 4th highest prevalence of physical inactivity in africa,5 using global surveillance instruments. however, we have some promising initiatives. we have a growing regional network, the african physical activity network (afpan), which is open to all interested parties, the vision of which is to ‘create a network of like-minded individuals and institutions engaged in promoting health through physical activity within the local context of countries and communities of africa’. (http://www.essm.uct.ac.za/afpan/ ) we have an active south african sports medicine association, which at present provides regional leadership for exercise is medicine, promoting exercise and physical activity as a ‘vital sign’. in addition, we have support at a policy level. the south african government, through the department of health, is currently drafting, in consultation with other sectors, a national plan for physical activity, and the department of education has re-emphasised the importance of physical education. many ngos operating in our region promote health for children and youth through participation in sport. it is timeous for each of us, in our sphere of influence, to promote the importance of physical activity, thereby to reduce the burden of disease associated with inactivity. whether we consult with urban planners, write a letter to parliament or the world health assembly, or simply teach students, guide and motivate patients, the message is the same … ‘to accumulate at least 30 minutes of moderate-to-vigorous activity on most, preferably all, days of the week’. as professor mike evans asks: ‘can you limit the amount of sitting and sleeping you do to just 23 and ½ hours every day?’ it’s the single most important decision one can make to improve health.6 references 1. who discussion paper: a comprehensive global monitoring framework and voluntary global targets for the prevention and control of ncds. http://www. who.int/nmh/events/2011/consultation_dec_2011/who_discussion_paper_ final.pdf (accessed 6 february 2012). 2. ralston j. developing targets for ncds: can we measure physical activity? http:// world-heart-federation.org/blog/2012/01/26/developing-targets-for-ncds-can-wemeasure-physical-activity/ (accessed 6 february 2012). 3. joubert j, norman r, lambert ev, et al. estimating the burden of disease attributable to physical inactivity in south africa in 2000. s afr med j 2007;97:725-731. 4. global advocacy for physical activity (gapa) the advocacy council of the international society for physical activity and health (ispah). ncd prevention: investments that work for physical activity. february 2011. www.globalpa.org.uk/ investmentsthatwork (accessed 6 february 2012). 5. sallis r. developing healthcare systems to support exercise: exercise as the fifth vital sign. br j sports med 2011;45:473-474. 6. evans m. 23 and 1/2 hours: what is the single best thing we can do for our health? http://www.youtube.com/watch?v=auains6higo (accessed 6 february, 2012) sajsm cpd true or false instructions 1. read the journal. all the answers will be found there. 2. go to www.mpconsulting.co.za to answer questions. accreditation number: mdb001/015/01/2014 (clinical) effective in 2014, the cpd programme for sajsm will be administered by medical practice consulting: cpd questionnaires must be completed online at www.mpconsulting.co.za a maximum of 3 ceus will be awarded per correctly completed test. april 2014 common acute and chronic musculoskeletal injuries among female adolescent field hockey players in kwazulu-natal, south africa (sa) 1. the majority of field hockey musculoskeletal injuries are to the upper extremities. 2. in field hockey, goalkeepers have the highest rate of injury. 3. chronic lower-back injuries in field hockey players have been associated with hip flexor contractures. collagen gene interactions and endurance running performance 4. there are ~20 known gene variants associated specifi cally with endurance performance. 5. both type v and vi collagen regulate collagen fibrillogenesis. 6. increased type v collagen production alters the mechanical proper ties of the tissue, leading to decreased endurance perfor mance. 7. the col3a1 and col12a1 genes serve as potential markers for endu rance running performance. steps that count! a feasibility study of a pedometer-based health promotion intervention in an employed, sa population 8. pedometers have become popular for use in physical activity inter ventions in various settings to facilitate behavioural change. 9. goal-setting, feedback on progress and strategies for overcoming barriers are common features for successful interventions to increase the volume of walking. micro-oscillations in positive and negative affect during competi tive laboratory cycle time trials 10. athletes were more likely to maintain or increase exercise intensity when positive affect was experienced. 11. levels of positivity and negativity reported by participants during exercise were shown to oscillate, providing evidence for the dynamic, emotive nature of sport performance. 12. high levels of negative affect and lower levels of positive affect were associated with better performances by the cyclists. 13. in self-regulation theory, monitoring of selfand norm-refer enced information enables individuals to make the necessary adjustments to minimise the discrepancy between desired and actual beha viour. 14. in a novel throwing task, negative affect was significantly higher in successful athletes, compared with failed conditions. 16. over the course of the time trial, particularly when athletes were striving to achieve a time goal, they only made an assessment regarding their performance and rate of goal progress at the halfway mark. the prevalence of self-reported neck pain in rugby union players in gauteng province, sa 16. a study among a cohort of rugby union players in gauteng province showed that over 50% of the players had neck pain at the time of the study. 17. most rugby union players with neck pain were treated by a biokineticist. 18. just over half of the rugby union players interviewed engaged in strength training specifically for their necks. 19. neck pain caused mild to moderate disability in 18% of the pla yers surveyed. 20. cervical trauma occurs most frequently during the lineout. http://www.mpconsulting.co.za http://www.mpconsulting.co.za original research 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license exploring the efficacy of low-level laser therapy and exercise for knee osteoarthritis a kholvadia, bhms, hms (hons), ma (hms); d constantinou, mbbch, bsc(med)hons, msc med, mphil, ffims, facsm; p j-l gradidge, b sp sc, b sp sc (hons), msc med, phd centre for exercise science and sports medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: a kholvadia (a.kholvadia@gmail.com) knee osteoarthritis (koa) is a prevalent, chronic disorder with functional, social and economic burdens.[1] the world health organization’s (who) global burden of disease 2010 study highlighted that, with africa’s attention on infectious disease, child and maternal health, the burden of non-communicable diseases, such as koa, has amplified.[2] a prevalence of 33% has been observed amongst older rural south africans, whilst south africans in urban areas show a higher prevalence of koa (55%).[3] urbanisation has resulted in increased life expectancy, increased ageing populations and higher levels of obesity-making osteoarthritis the fourth leading cause of disability by the year 2020.[2] furthermore, common koa-related symptoms include pain and joint stiffness which negatively influences disability and functionality.[1,2] contemporary evidence for identifying, diagnosing and managing koa varies, depending on the stage of disease progression and severity.[1] the main goal of management for koa is to alleviate the symptoms and delay the progression of the disease,[4] with therapeutic modalities, including physical therapy, pharmacological intervention, and surgery.[4] the current treatment regimen for koa aims at controlling pain and improving the joint function to enhance functionality through pharmacological intervention and physical therapies.[4] with disease progression, surgical intervention is considered as activities of daily living decreases.[4] physical rehabilitation is important as a tool for disease management in the early phases of koa diagnosis, particularly as evidence shows that compared with sedentary patients, those patients who underwent exercise therapy had significantly better outcomes.[5] contemporary evidence demonstrates that low-level laser therapy (lllt) (also known as photobiomodulation) in particular, together with physical therapy, has the potential for better outcomes than conservative therapy alone.[6,7,8] data from these studies observed that participants in the group using lllt and combined with exercise experienced increased pain relief and improved joint functionality and mobility. however, there are other studies showing no pain relief with lllt alone.[9,10] given the conflicting outcomes from these studies, the aim of this study was to investigate the efficacy of combined lllt and exercise compared with exercise or lllt alone in a south african cohort of patients diagnosed with koa. methods study design a descriptive, intervention study design was used to evaluate the differences between the groups participating in lllt and exercise alone, and a combination of the two modalities. participants were randomised into one of the three groups using pre-sealed envelopes attached to the batch of documents provided to prospective participants at baseline testing. a single blind methodology was employed as the principal investigator carried out the intervention programmes. the study participants were unaware of the diverse intervention modes of the study. furthermore, a factorial design experiment, which is a variation of the between-group design experiment, was used. this study consisted of three treatment variables which examined the independent and simultaneous background: knee osteoarthritis (koa) is a prevalent, chronic disorder with excessive functional, social and economic burdens. the goal of treatment is to alleviate the symptoms and slow the progression. documenting the effects of exercise and lllt as co-modalities in the management of koa allows practitioners to implement this management tool as part of koa rehabilitation, resulting in the earlier discharge from a supervised rehabilitation setting. objective: the purpose of this study was to determine the effect of low-level laser therapy (lllt) in the treatment of knee osteoarthritis (koa). a randomised controlled trial (rct) was conducted on 111 participants (aged between 40-75 years) diagnosed with koa. participants were randomised into an exercise (n=39), lllt (n=40), or a combined exerciselllt (n=32) group. methods: the western ontario and mcmaster universities osteoarthritis index (womac) scale was used to assess pain and functionality. knee range of motion was assessed using a goniometer, and the one-minute timed sit–to-stand test measured physical functionality at four time points: (t1) baseline, (t2) post 12-session intervention, (t3) one-month post intervention and (t4) three-month’s post intervention. knee circumference was measured using a measuring tape. results: womac pain and functionality scale and knee circumference scores decreased in all three groups (p<0.05), but the combined exercise-lllt group demonstrated better outcomes than the lllt or exercise alone groups respectively. the combined exercise-lllt group showed better acute and long-term benefits with participants experiencing a 3.5 centimetre decrease in knee circumference, 24 point improvement in the womac pain and functionality scale, and a four repetition increase in physical functionality. conclusion: the findings suggest that lllt is a viable tool for managing koa when used in conjunction with physical exercise. keywords: photobiomodulation, physical therapy, degenerative joint disease s afr j sports med 2019;31:1-5. doi: 10.17159/2078-516x/2019/v31i1a6058 mailto:a.kholvadia@gmail.com http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6058 https://orcid.org/0000-0002-1650-6116 https://orcid.org/0000-0002-3363-7695 https://orcid.org/0000-0001-5225-1184 original research sajsm vol. 31 no. 1 2019 2 effect of the respective treatments on the outcome measures of the knee’s range of motion (rom), knee circumference, womac pain scale, and physical functionality. this research design allowed the study to explore the effects of each treatment separately, together with the effect on the variables explored, thereby providing a rich and encompassing multidimensional view. the data collection for the randomised controlled trial (rct) was conducted at a biokinetics rehabilitation centre in johannesburg, south africa. participants male and female knee osteoarthritis patients (n=120) from johannesburg, aged 40-75 years, and meeting all the study’s inclusion criteria, were recruited to voluntarily participate in this randomised control trial after being referred to the study by various medical practitioners. prospective participants were excluded from the study if they were pregnant, diagnosed with cancer or epilepsy and if they were physically unable to complete one or more tests in the battery of physical tests required for the study. the participants were randomly allocated to an exercise group, a lllt group or a combination of exercise plus lllt group respectively. sealed envelopes were used and attached to the initial testing documentation after the baseline testing (t1) was completed. these presealed envelopes were marked and randomly attached to the back of each batch of baseline testing forms indicating an assignment to a prospective intervention group. there was a dropout rate of 0%, 2.5% and 20% in the exercise, lllt and combination treatment groups respectively. one hundred and eleven participants completed the study (exercise group, n=39, lllt group, n=40 and the combined exercise-lllt group, n=32). all participants were thoroughly informed regarding consent to participation and withdrawal, testing procedures and intervention programmes. written informed consent was obtained from all participants prior to data collection (t1). ethics approval was obtained from the faculty of health sciences human research ethics committee (medical) at the university of the witwatersrand (certificate number: m161112). knee circumference knee circumference was assessed using a measuring tape while the participant was supine; with the affected knee supported by a towel to create a 30° flexion in the knee which allowed the relaxation of the quadriceps muscle. [11] the site of joint circumference measurement was proximal (two cm above the mid patella), mid and distal (two cm below the mid patella) recorded to the nearest millimetre (mm). pain and functionality management the western ontario and mcmaster universities arthritis index (womac) is a self-administered questionnaire which can be used to describe and evaluate pain and function in patients with osteoarthritis of the knee. this questionnaire was chosen for its validity and reliability as a tool in reporting koa.[12] the womac measures five items for pain (score range 0–20), two for stiffness (score range 0–8), and 17 for functional limitation (score range 0–68). questions regarding physical functioning cover everyday activities such as stair use, standing up from a seated or lying position, bending, walking, getting in and out of a car, shopping, putting on or taking off socks, lying in bed, getting in or out of a bath, sitting, and doing heavy and light household duties. [12] the change in the womac score was used as the outcome variable of pain and functionality during the study. knee range of motion (rom) bilateral rom was measured using a baseline® goniometer to the nearest degree (°) while the participant was supine.[11] for flexion measurements the participant was asked to bring the foot as close to the buttocks as possible. for extension measurements, the participant was instructed to actively straighten the knee. physical functionality the one-minute timed sit-to-stand test was used to measure physical functionality.[13] the participant was requested to sit in the middle of a 50 cm high chair with his/her arms crossed against the chest, feet flat on the floor and back straight up against the backrest of the chair. the participant was then instructed to sit and stand respectively. a stopwatch was used to count down 60 seconds and the number of completed repetitions recorded. intervention there were three intervention groups, i.e. exercise, lllt, and a combined exercise-lllt. exercise group the exercise programme was conducted three times per week and consisted of 12 sessions based on rehabilitation guidelines.[5] the exercise protocol included four different types of exercises, i.e. flexibility (quadriceps, calf muscles and hamstrings), stability (quad setting, single leg balance), strength and endurance (supine and prone straight leg raises, abductor squeezes, step-ups, calf raises), designed to maintain and improve knee functionality through improved muscular strength, rom and locomotor function of the knee joint. the programme was self-paced, starting at a low intensity and became progressively more challenging. the principal investigator supervised all exercise sessions and determined individual participant exercise progression. low-level laser therapy (lllt) group participants in the lllt group were exposed to three different arrays as part of the lllt protocol over a period of 12 sessions, with each session progressing from 35 min to 45 min.[14] there are no frequency protocol guidelines on the use of lllt for koa, therefore sessions were scheduled for times a week to maintain uniformity across all three intervention groups. a circumferential application method was employed. three placements with medial and lateral applications overlapping at the patella’s surface were used. the participant’s knee was set at 60°-70° for optimal penetration of light from the lightoriginal research 3 sajsm vol. 31 no. 1 2019 emitting diodes (leds).[14] combined exercise and lllt group the combined exercise and lllt group underwent a protocol that included both the exercise rehabilitation and the lllt intervention programmes described above. the exercise sessions were done preceding the lllt intervention. these sessions were scheduled for three times a week. statistical analysis statistical analysis was performed using statistica v13.3 (tibco software. statsoft inc.). after assessing the normal distribution of the data using the shapiro-wilks test, descriptive data were presented as mean ± standard deviation (sd). the differences between baseline and post-study period analysis of covariance (ancova) are presented as effect sizes (cohen’s d) and the differences between study groups were determined using anova (analysis of variance). paired t-tests were used to measure differences between baseline and post-intervention data for all variables. independent t-tests were performed to determine if the intervention groups differed in basic participant characteristics. repeated measures anova tests with between-subjects effects (exercise vs. lllt or exercise vs. combination group) and within-group effects (t2, t3, t4) were performed to indicate the differences in measurements from baseline. significance was accepted at p<0.05. results participant characteristics the one hundred and eleven participants in the study were randomly allocated into the three intervention groups exercise (n=39), lllt (n=40), and combined exercise-lllt (n=32) groups, respectively. most of the participants were women (n=85, 77%), with a mean age of 61.8 ± 5 years. the exercise group exhibited the highest bmi at 36.1 ± 3.7 kg/m-2) followed by the lllt group (31.6 ± 4.5 kg/m-2) and the combined exercise-lllt group (29.6 ± 4.7 kg/m-2). knee osteoarthritis variable outcomes knee circumference varying effects were observed in all three groups for the key outcomes. however, the combined exercise -lllt group demonstrated improved efficacy for the outcome measures of knee circumference while the post-intervention (12-week) knee circumference decreased significantly in all groups (p<0.05), this effect was highest in the lllt group compared to the combined exercise-lllt and exercise groups (table 2). womac pain and functionality scale table 2 shows that all groups experienced improvements in the womac pain and functionality scale, but this was most noticeable in the combined lllt-exercise group (p<0.05). the values at baseline were comparative in all groups. however, the exercise vs. lllt had significantly greater effect sizes at t3 and t4 compared to the exercise and combined exercise-lllt groups. knee rom knee extension rom was significantly lower in the combined exercise-lllt and lllt groups compared with the exercise group at baseline (table 1). only the combination group experienced significant improvements following the intervention (table 2). baseline knee flexion rom was higher in exercise group compared with the lllt and combined exercise-lllt group (p<0.005); however, the effect of the intervention was only significant in the combined exerciselllt group (table 2). sit-to-stand baseline values for physical functionality (measured by the sitto-stand test) were similar across all three intervention groups. table 2 demonstrates that the combined exercise-lllt group had the greatest improvements in the sit-to-stand repetitions following the intervention, and this effect was evident at the t3 and t4 time points. table 1. baseline and post-intervention characteristics exercise (n=39) lllt (n=40) combined exercise-lllt (n=32) baseline post-intervention baseline post-intervention baseline post-intervention knee circumference proximal patella (cm) 41.4 ± 6.1 38.0 ± 6.1* 41.3 ± 6.1 40.0 ± 6.1* 43.5 ± 7.3 41.1 ± 7.4* knee circumference mid patella (cm) 36.6 ± 5.1 38.9 ± 4.5* 38.5 ± 4.8 40.3 ± 4.5* 40.0 ± 4.6 39.2 ± 3.9* knee circumference distal patella (cm) 37.4 ± 4.3 36.6 ± 4.2* 36.3 ± 4.7* 37.9 ± 3.1* 37.7 ± 4.6 37.5 ± 4.0* womac 56.6 ± 10.1 60.8 ± 9.8* 59.1 ± 10.2 61.5 ± 11.3* 56 ± 10.8 65.6 ± 9.9* rom extension (⁰) 2.1 ± 2.8 1.1 ± 1.9* 1.6 ± 2.5 1.4 ± 2.1* 1.4 ± 2.5 0.8 ± 1.6* rom flexion (⁰) 99.5 ± 14.6 102.3 ± 16.9 96 ± 17.4 103.7 ± 11* 95.2 ± 19.1 108.3 ± 11.9* sit-to-stand (reps) 17 ± 2.5 19.7 ± 3.5* 17.1 ± 2.9 19.6 ± 3.2* 17.4 ± 3.5 21.3 ± 4.1* data presented as mean ± sd. * indicates p<0.05 vs. baseline values lllt, low-level laser therapy; womac, western ontario and mcmaster universities arthritis index; rom, range of motion; ⁰, degrees; reps, completed repetitions. original research sajsm vol. 31 no. 1 2019 4 discussion this study aimed to evaluate the effect of utilising lllt in combination with exercise in comparison to the use of exercise or lllt as stand-alone therapies for the conservative management of patients diagnosed with koa. varying effects were observed in all groups for the key koa study outcomes; however, the combined exercise-lllt group demonstrated the best effects when compared with the exercise or lllt groups alone. the decrease in knee circumference values and improvements in the womac pain and functionality scores indicate structural enhancement in the joint. a decrease in joint effusion was evident by the decrease in knee circumference scores and an improvement in womac pain and functionality score, as supported by other authors such as fukuda et al. [7] , alfredo et al.[8,6]. improvements of between 11 and 12.9 points in a period of 2-6 months post-intervention establishes a minimally clinical important difference (mcid) when using the womac as an evaluation tool.[15] the study showed a greater than 11 point improvement (calculated mean difference between baseline and post-intervention testing) in both groups exposed to lllt at t3 and t4. functional improvements were observed by the increased number of timed sit-to-stand repetitions and improvements in knee flexion rom. the findings from this study set up a discussion point for both structural and functional management traits in koa. this research study suggests that analgesia associated with lllt results in the anti-inflammatory properties on the articular capsule as suggested by the world association of laser therapy (walt), with similar results being produced, resulting in both pain relief and a decrease in knee circumference values.[6,7,8] the main finding of this study is that of an adjunctive effect of lllt with the conservative exercise management of koa. the findings showed that the koa outcomes significantly improved across all three intervention groups (p<0.05), with the table 2. temporal outcome measures for knee osteoarthritis (koa) patients with different interventions exercise (n=39) lllt (n=40) combined exercise-lllt (n=32) variable t2 t3 t4 t2 t3 t4 t2 t3 t4 knee circumference proximal patella (cm) mean ± sd 40.0 ± 6.1* 38.3 ± 6.4* 38.0 ± 6.1* 38.0 ± 6.1*† 36.7 ± 6.1*† 35.2 ± 6.2*† 41.1 ± 7.4* 39.6 ± 6.7*† 38.3 ± 6.7* effect size 0.2 (-0.2:0.7) 0.5 (-0.0:0.9) 0.6 (0.1:1.0) 0.3 (-0.1:0.8) 0.3 (-0.2:0.7) 0.4 (0.0:0.9) 0.2 (-0.6:0.3) 0.2 (-0.7:0.3) 0.1 (-0.5:0.4) knee circumference mid patella (cm) mean ± sd 40.3 ± 1.4 38.6 ± 4.5* 37.4 ± 4.5* 38.9 ± 4.5† 36.8 ± 4.2*† 36.0 ± 4.2* 39.2 ± 3.9† 37.0 ± 3.1*† 36.5 ± 3.7*† effect size 0.1 (-0.6:0.3) 0.4 (-0.9:0.0) 0.2 (-0.6:0.3) 0.3 (-0.1:0.7) 0.4 (0.0:0.9) 0.3 (-0.1:0.8) 0.2 (-0.2:0.7) 0.4 (0.0:0.9) 0.2 (-0.2:0.7) knee circumference distal patella (cm) mean ± sd 37.9 ± 3.8* 38.0 ± 4.4 37.4 ± 3.6* 36.6 ± 4.2† 36.4 ± 4.2† 36.0 ± 4.2† 37.5 ± 4.0 37.3 ± 4.0 36.5 ± 3.7*† effect size 0.1 (-0.6:0.3) 0.1 (-06:0.3) 0.0 (-0.5:0.4) 0.3 (-0.1:0.8) 0.4 (-0.1:0.8) 0.4 (-0.1:0.8) 0.1 (-0.4:0.6) 0.2 (-0.3:0.3) 0.3 (-0.2:0.7) womac mean ± sd 61.5 ±11.3* 65.3 ±13.1* 70.5 ±11.8* 70.8 ± 9.8*† 76.9 ± 9.2*† 80.7 ± 8.5*† 65.6 ± 9.9*† 72.0 ± 8.7*† 78.0 ± 8.5*† effect size 0.5 (0.9:0.0) 0.7 (-1.2:0.3) 1.3 (-1.7:0.8) 0.9 (-1.3:-0.4) 1.0 (-1.5:0.6) 1.0 (-1.4:-0.5) 0.4 (-0.8:0.1) 0.6 (-1.1:-0.1) 0.7 (-1.2:-0.2) rom extension (⁰) mean ± sd 1.4 ± 2.1* 0.7 ± 1.5* 0.3 ± 0.9* 1.3 ± 1.9* 0.6 ± 1.3* 0.2 ± 0.6* 0.8 ± 1.6*† 0.4 ± 1.0*† 0.9 ± 0.4*† effect size 0.3 (-0.1:0.8) 0.6 (0.2:1.1) 0.9 (0.4:1.3) 0.1 (-0.4:0.5) 0.1 (-0.3:0.5) 0 (-0.4: 0.4) 0.3 (-0.2:0.8) 0.3 (-0.2:0.7) 0 (-0.5: 0.5) rom flexion (⁰) mean ± sd 103.7 ±13.4* 108.1 ± 12.4* 111.4 ± 11.5* 102.3 ± 16.9* 107.4 ± 14.9* 109.5 ± 13.2* 108.3 ± 11.9*† 112.3 ± 11.3*† 115.2 ± 10.3*† effect size 0.3 (-0.7:0.2) 0.6 (-1.1:-0.2) 0.9 (-1.4:0.4) 0.1 (-0.4:0.5) 0.1 (-0.4:0.5) 0.2 (-0.3:0.6) 0.4 (-0.8:0.1) 0.4 (-0.8:0.1) 0.3 (-0.8:0.1) sit-to-stand (reps) mean ± sd 19.5 ± 3.0* 23 ± 4.5* 26 ± 3.5* 19.7 ± 3.5* 25.5 ± 3.0*† 25.5 ± 4.0* 21.2 ± 4.0*† 25.5 ± 3.0*† 30.0 ± 3.0*† effect size 0.9 (-1.4:-0.4) 1.6 (2.1:-1.1) 0.3 (-3.6:-2.3) 0.1 (-0.5:0.4) 0.7 (-1.1:-0.2) 0.1 (-0.3:0.6) 0.5 (-0.9:0.0) 0.7 (-1.1:-0.2) 1.2 (-1.7:-0.7) data presented as mean ± sd with effect sizes (95% ci). bold font indicates effect size >0.02; * indicates p<0.05 (t1 vs t2, t1 vs. t3, t1 vs. t4) using independent tests; † indicates p<0.05 exercise vs. lllt, and exercise vs. combined exercise-lllt. lllt, low-level laser therapy; womac, western ontario and mcmaster universities arthritis index; rom, range of motion; ⁰, degrees; reps, completed repetitions; t2, post intervention; t3, 1 month post-intervention; t4, 3 months post intervention. original research 5 sajsm vol. 31 no. 1 2019 lllt group showing better short-term pain relief, but the combined exercise-lllt group demonstrated better longterm reduction in pain symptoms. this implies a better residual effect when exercise treatment is applied with a laser. indeed, fear of pain is the main reason for koa patients reducing their physical activity.[6] the combined exerciselllt treatment can improve both functional strength (short and long-term), knee joint rom and sit-to-stand scores thereby contributing to improved activities of daily living and quality of life. the findings of this study are supported by work undertaken by alfredo et al. [6] where the benefits of combined intervention exposure were maintained for three months post exposure to the intervention. in this present study participants were recruited from one geographic area and therefore further investigation is needed to confirm the findings in other geographic areas. furthermore, participants were referred to the study by multiple medical practitioners and therefore a standard diagnostic criterion was not applied but it was rather a referral based on each practitioner’s specific diagnostic criteria. conclusion in conclusion, this 12-week rct demonstrated that the addition of lllt with exercise strengthens the effects on koa outcomes, suggesting that the efficacy of lllt as an adjunct form of therapy should be included in the non-surgical management of koa. the data highlights the potential carryover effect of this tool in diagnosed koa patients; however, further investigations are needed to confirm the observed effect. author contributions: a kholvadia conducted the study, performed the statistical analysis, and wrote the paper. all authors read, commented and approved the final version of the manuscript. references 1. felson dt, lawrence rc, dieppe ra, et al. osteoarthritis: new insights. part 1: the disease and its risk factors. ann intern med 2000; 133(8):635-646 [doi: 10.7326/0003-4819-1339-200011070-00015] 2. woolf ad. global burden of osteoarthritis and musculoskeletal diseases. bmc musculoskelet disord 2015; 16(suppl 1): s3. [doi: /10.1186/1471-2474-16-s1-s3] 3. usenbo a, kramer v, young t, musekiwa a. prevalence of arthritis in africa: a systematic review and meta-analysis. plos one 2015; 10(8): e0133858. [doi:org/10.1371/journal.pone.0133858] 4. michael jw, schlüter-brust ku, eysel p. the epidemiology, etiology, diagnosis, and treatment of osteoarthritis of the knee. dtsch arztebl int 2010; 107(9): 152-162. [doi: 10.3238/arztebl.2010.0152] 5. fransen m, mcconnell s, harmer ar, et al. exercise for osteoarthritis of the knee: acochrane systematic review. br j sports med 2015; 49(24):1554-1557. [doi: 10.1136/bjsports-2015095424] 6. alfredo pp, bjordal jm, junior ws, et al. long-term results of a randomized, controlled, double-blind study of low-level laser therapy before exercises in knee osteoarthritis: laser and exercises in knee osteoarthritis. clin rehabil 2018; 32(2): 173178. [doi: 10.1177/0269215517723162] 7. fukuda vo, fukuda ty, guimarães m, et al. short-term efficacy of low-level laser therapy in patients with knee osteoarthritis: a randomized placebo-controlled, double-blind clinical trial. rev bras ortop 2015; 46(5): 526-533. [doi: 10.1016/s2255-4971(15)30407-9] 8. alfredo pp, bjordal jm, dreyer sh, meneses srf, zaguetti g, ovanessian v, et al. efficacy of low level laser therapy associated with exercises in knee osteoarthritis: a randomized double-blind study. clin rehabil. 2012; 26(6); 523-533. [doi: 10.1177/0269215511425962] 9. bjordal, jm, johnson, mi, lopes-martins ra, et al. short-term efficacy of physical interventions in osteoarthritic knee pain: a systematic review and meta-analysis of randomized placebocontrolled trials. bmc musculoskelet disord 2007; 8:51. [doi: 10.1186/1471-2474-8-51] 10. bülow, pm, jensen, h, danneskiold-samsøe b. low power gaal-as laser treatment of painful osteoarthritis of the knee. a double-blind placebo controlled study. scand j rehabil med 1994; 26(3): 155-159. [pmid: 7801065] 11. jakobsen tl, christensen m, christensen ss, et al. reliability of knee joint range of motion and circumference measurements after total knee arthroplasty: does tester experience matter? physiother res int 2010; 15(3): 126-134. [doi: 10.1002/pri.450] 12. salaffi f, leardini g, canesi b, et al. reliability and validity of the western ontario and mcmaster universities (womac) osteoarthritis index in italian patients with osteoarthritis of the knee. osteoarthr cartilage 2003; 11(8): 551-560. [doi: 10.1016/s1063-4584 (03)00089-x] 13. huber eo, meichtry a, de bie ra, et al.. construct validity of change scores of the chair stand test versus timed up and go test, koos questionnaire and the isometric muscle strength test in patients with severe knee osteoarthritis undergoing total knee replacement. man ther 2016; 21: 262-267. [doi: 10.1016/j.math.2015.09.012] 14. kahn f. low intensity laser therapy in clinical practice. meditech international , 2006: 44–45. 15. williams vj, piva sr, irrgang jj, et al. comparison of reliability and responsiveness of patient-reported clinical outcome measures in knee osteoarthritis rehabilitation. j orthop sports phys ther 2012; 42(8): 716-723. [doi: 10.2519/jospt.2012.4038]. km_c227-20180517092543 there are many examples of how sport has transcended barriers and unified the nation. perhaps the most famous example is the springboks winning the 1995 world cup, followed by nelson mandela handing the trophy to françois pienaar and then the euphoria which swept the country for a short period. indeed the importance of this moment has been captured in a soon-tobe-released movie, the human factor, directed by clint eastwood with superstar actors morgan freeman and matt damon playing nelson mandela and francois pienaar respectively. subsequent to the 1995 event there have been episodic examples, prompting nelson mandela to make his famous quote: ‘sport has the power to change the world, to inspire, to unite people in a way that little else can.’ however, just as sport has the power to unite the nation, so it too has the power to divide the nation. consider the example of caster semenya, winner of the 800 m race at the world athletics championships in august 2009. the dominant way in which she won the race against the best in the world should have brought another glorious moment to the nation. instead, information leaked out to the media that the iaaf were conducting a sex test to exclude a rare medical condition which might have given her an unfair advantage over the other female athletes in her race. this leaked report was the catalyst for a range of responses from politicians, commentators, administrators and gender rights activists. politicians in particular seized the opportunity to launch their inflated egos into the public light, making absurd accusations and in the process further polarising public opinion. it seemed the media were not interested in the views of the expert medical practitioners and scientists, particularly after the president of athletics south africa was reported to have said: ‘let me warn professors and scientists that the only scientists i believe in are the parents of this child. one scientist from a stupid university somewhere is going to erase the entire life of this girl.’ (www. sport24.co.za, 2009-08-25). the policy of the iaaf is that there will be no compulsory, standard or regular gender verification during iaaf championships. any problems related to gender should be picked up by the national team doctors during health checks or by medical/doping delegates at specimen collection during doping control at major championships. if there is any suspicion or an official challenge, the athlete can be asked to attend a medical evaluation before a panel consisting of a gynaecologist, endocrinologist, psychologist, internal medicine specialist and expert on gender/transgender issues (iaaf policy on gender verification, prepared by the iaaf medical and anti-doping commission, 2006). this is usually conducted in private, out of the media and public focus. with all the mudslinging, accusations, and counter-accusations, the focus of the debate has shifted, and the poor girl in the midst of the most difficult time of her life is being used as a pawn either by politicians to elevate their own person profile, or by administrators to deflect some of the blame targeted at them for the shoddy way in which the whole affair has been handled. however, with any bad experience there are lessons to be learnt. firstly, someone needs to be held accountable for leaking information from the iaaf to the australian journalist. strategies need to be implemented to prevent leaks from happening again. secondly, the journalist who wrote the story needs to take a look deep into his heart – do the positive outcomes of a sensational story really outweigh the negative outcomes which included personal damage and humiliation to the girl and her family? how would the same journalist have felt had one of his colleagues written a deeply personal story about his child for the whole world to read? thirdly, the administrators of the sport need to take some accountability and instead of shouting loud to deflect blame, rather do the job they were entrusted to do. fourthly, so-called ‘experts’ who are quick to form an alliance with the media, ready for a dial-a-quote, should understand that there are other channels in which they can operate and communicate. by trying to explain an extremely complicated and sensitive medical/scientific topic to a journalist seeking sensationalism is only adding fuel to the fire. perhaps it is time to re-visit the ethics around communicating personal details about another person, whether it be an athlete or a patient? let us hope that lessons have been learnt and we do not see history repeating itself sometime in the future. in the meantime there is a young lady and her family who need to deal with their predicament. may we all demonstrate our love and support to help her through this difficult period. it is time that the unifying side of sport regains its rightful place in society. on a positive note, this is a bumper edition of the journal! we have decided to merge issue 3 of the journal with the supplement edition coinciding with the13th biennial conference of the south african sports medicine association (21 – 23 october 2009). we are graced by the presence of experts from around the world and anticipate their contribution will make the conference a wholehearted success! we hope you enjoy reading the papers in this edition of the journal and also the material associated with the presentations at the conference. mike lambert editor-in-chief the power of sport a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial 66 sajsm vol 21 no. 3 2009 original research 1 sajsm vol. 30 no. 1 2018 a four-week home-based exercise programme is effective in treating subacute low back pain in adults m j lumb, hons, l lategan, phd department of sport and movement studies, faculty of health sciences, university of johannesburg, cnr joe slovo drive and beit st, 2001 doornfontein, johannesburg gauteng, south africa corresponding author: m j lumb (michaeljameslumb@gmail.com) low back pain (lbp) is a prevalent condition affecting a large portion of the population worldwide. [1] it is pain that is experienced in the lumbar spine region. it is also one of the leading causes of morbidity and work absenteeism and therefore, cost-effective strategies used to treat this condition are important. [1] over 70% of the global population will experience lbp during their lifetime. [1] low back pain is a very common health problem, peaking between the ages of 35 to 55 years old. [1] numerous studies have demonstrated the favourable effects of rehabilitative exercise on reducing subacute (four weeks to three months) and chronic (longer than three months) lbp.[2,3] some studies have also demonstrated that rehabilitative exercise is not effective when treating acute (<4 weeks) lbp.[2,3] rehabilitative exercise combined with education is considered essential when treating lbp and is regarded as the ideal intervention in its prevention.[4,5,6] other interventions, such as education alone, shoe inserts and back braces/belts, do not seem to prevent cases of low back pain[6]. in developing countries like south africa, where more than 55% of its population live below the poverty line and are not covered by medical insurance, finding cost-effective and evidence-based strategies to treat lbp are important. [7] exercise therapy has numerous benefits in treating lbp, specifically subacute [2,3,8] and chronic lbp [2,3], as it aims to correct biomechanical discrepancies and muscle imbalances. [2,3,8]. exercise helps to develop core stability and increases range of motion. [2] a combination of aerobic, strength and stretching exercises have been reported to be more effective in treating lbp than leaving it untreated. [2] certain studies have displayed the effectiveness of non-supervised exercise in the reduction of chronic low back pain and functionality at work. [9] exercise therapy has been shown to be more cost-effective than other treatments in the treatment of chronic and subacute low back pain. [10] however, few studies have explored the effectiveness of unsupervised, home-based exercises in patients with subacute lbp. methods study design a quantitative, experimental, randomised controlled trial design was used in this research. the groups were matched by gender and age, and the participants were blinded in terms of group allocation. the effectiveness of a four-week home-based exercise programme was compared to a control group at posttest. both groups were followed for a further four weeks after the intervention period to assess the effectiveness of the exercise programme. thus, the whole experiment was conducted over an eight-week period. at the end of the study, the control group was offered the same protocol that was given to the exercise intervention group. the study protocol was approved by the university of johannesburg’s faculty of health sciences research ethics committee (south africa) (rec-241112-035). participants and selection criteria the research population consisted of male and female adults background: low back pain (lbp) is a prevalent condition affecting a large portion of the population worldwide and it is one of the leading causes of morbidity and work absenteeism. objectives: to investigate the effectiveness of a four-week, home-based exercise programme in treating subacute lbp in adults. methods: a quantitative experimental research design was used. twenty male and female adults (between 18 and 65 years) with subacute lbp were recruited by means of advertisements and word of mouth and allocated into either a control group (cg) or a home-based exercise group (hg). both groups underwent a pre-test that consisted of answering two questionnaires, the visual analogue scale for pain (vasp) and the oswestry low back pain and disability questionnaire. the cg received no intervention over the fourweek intervention period, while the intervention group (hg) was given an exercise programme and instructed to perform the exercises at home, three times a week for four weeks. after four weeks (post-test), the two questionnaires were repeated. after eight weeks (the follow-up test) both groups again completed the two questionnaires. descriptive statistics, nonparametric inferential statistics and cohen’s effect size (d) were used to analyse the data and statistical significance was set at a confidence level of 95% (p≤0.05). results: following the home-based exercise intervention there were significant improvements observed in low back pain and function for the hg. the hg’s oswestry scores improved significantly (p=0.005) and their vasp also showed a significant improvement (p=0.011). significant improvements also occurred between the pre-test and fourweek follow-up for the hg’s oswestry score (p=0.021) and for the hg’s vasp (p=0.005). no significant improvement was found for the cg between pretest and post-test or between pretest and the four-week follow-up. large effect sizes (d>0.8) were also observed for the hg between the pretest and the post-test (d=1.6), as well as between the hg and the cg at post-test (d=1.5) and at the four-week follow-up (d=1.6). conclusion: the exercise intervention resulted in statistically significant and clinically significant improvements in both function and pain in adults with subacute lbp. keywords: musculoskeletal rehabilitation, spine, function, movement s afr j sports med 2018;30:1-6. doi: 10.17159/2078-516x/2018/v30i1a5020 http://dx.doi.org/10.17159/2078-516x/2018/v30i1a5020 original research sajsm vol. 30 no. 1 2018 2 (18-65 years) who suffered from subacute lbp. prospective participants were given an information letter explaining the research project and an informed consent form which was signed by the participants indicating their willingness to take part in the research project. participants completed a medical history questionnaire to determine if they met the inclusion criteria: namely, that participants had to be between the ages of 18 and 65 years, and suffered from non-specific lbp [11 for more than four weeks but less than three months. all participants had to be able to communicate in english. the diagnosis was determined by the researcher. the participant’s medical history and exclusion criteria were also examined by the researcher the exclusion criteria included spinal surgery within the last year, a positive straight leg raise test indicative of referred pain, cauda equina syndrome, any contraindications to exercise, and symptoms such as the following: swelling and acute inflammation, the inability to perform activities of daily living, bowel or bladder dysfunctions, rheumatoid arthritis, metabolic or malignant bone diseases, pregnancy, and uncontrolled cardiovascular disease. a sample of 20 individuals (35.8±15.6 years; 11 males and 9 females) with subacute lbp who either responded to advertisements or heard about the study through family, friends or acquaintances were included. the participants were randomly assigned to either a control group (cg) or a homebased exercise group (hg) and, apart from gender, no attempt was made to match the two groups. participants were blinded in terms of group allocation while the researcher was not. study procedure participants completed two questionnaires: a standard 10 cm visual analog scale for pain (vasp) and the modified oswestry lbp disability questionnaire (oswestry). the validity and reliability of these two questionnaires have been previously established. [12,13] both the vasp and the oswestry questionnaires were completed prior to the intervention (pretest), at the end of the four-week intervention (post-test), and at the end of eight weeks (follow-up test). in addition, the vasp was completed by both groups at the end of each of the four intervention weeks to monitor the pain level of each participant. table 1. exercise programme week 1 week 2 week 3 week 4 warm-up 5 min aerobic exercise including walking, cycling, arm ergo or swimming (rpe: 11-13) 5 min aerobic exercise including walking, cycling, arm ergo or swimming (rpe: 11-13) 10 min aerobic exercise including walking, cycling, arm ergo or swimming (rpe: 11-13) 10 min aerobic exercise including walking, cycling, arm ergo or swimming (rpe: 11-13) stretches active slr hip flexor child’s pose lumbar rotation to both sides (2 x 15 sec) active slr hip flexor child’s pose lumbar rotation to both sides (2 x 20 sec) active slr hip flexor child’s pose lumbar rotations to both sides (3 x 20 sec) active slr hip flexor child’s pose lumbar rotations to both sides (3 x 30 sec) strength and endurance pelvic bridges heel slides four-point kneeling with active shoulder flexion side bridge on knees prone lumbar hyperextension (thorax lift only) (2 x 10 reps/sec) (30 sec rest between sets) pelvic bridges heel slides four-point kneeling with active shoulder flexion side bridge on knees prone lumbar hyperextension (thorax lift only) (2 x 15 reps/sec) (30 second rest between sets) single leg pelvic bridges (2 x 10 reps) bicycle kicks (2 x 10 reps) four-point kneeling with alternative shoulder flexion and hip extension (2 x 15 reps) side bridge (2 x 15 sec) prone back extension with arms & legs lift (2 x 8-10 reps) (30 sec rest between sets) single leg pelvic bridges (2 x 15 reps) bicycle kicks (15 reps, 2 sets) four-point kneeling with alterative shoulder flexion and hip extension (2 x 20 reps) side bridge (2 x 20 sec) prone back extension with arms & legs lift (2 x 10-12 reps) (30 sec rest between sets) stretches child’s pose (2 x 15 sec hold) child’s pose (2 x 20 sec hold) child’s pose (3 x 20 sec hold) child’s pose (3 x 30 sec hold) table 2. demographics of participants group n male (n) female (n) age (mean) standard deviation hg 10 6 4 39.7 (18.0) 18.0 cg 10 5 5 31.9 (12.5) 12.5 total 20 11 9 35.8 (15.6) 15.6 hg, home-based exercise group; cg, control group table 3. session compliance for home-based exercise group (n=10) week number of sessions mean median standard deviation p-value week 1 25 2.5 2.0 1.0 0.21 week 2 24 2.4 2.0 0.8 0.14 week 3 22 2.2 2.0 1.0 0.85 week 4 22 2.2 2.0 1.2 0.71 original research 3 sajsm vol. 30 no. 1 2018 intervention the hg received an exercise programme and were requested to perform the exercises three times a week for four weeks. the hg participants received one explanation and demonstration of the exercises and a printed copy of the exercise programme (with written instructions and pictures). the cg participants took part in all the testing procedures, but they did not receive any intervention other than the advice to rest. both groups provided feedback (via sms or email) on a weekly basis regarding their vasp. the current study utilised aerobic warm-up exercises, static stretches and resistance exercises from previous research studies (table 1). [14-19] the resistance exercises changed in week three and week four to allow for progression. each week the exercises were also progressed by the researcher (as indicated in the programme) in terms of either repetitions, sets, duration, or type of exercise. the researcher also had to be satisfied that the participants were able tolerate the progressions (based on weekly vasp feedback). data analysis the research used descriptive statistics. tests of normality (shapiro-wilk test) were conducted for each of the dependant variables. based on the results of the shapiro-wilk test, nonparametric statistical tests were performed, including the mann-whitney u test, friedman test, and the wilcoxon signed rank test. the mann-whitney u test was used to test differences between two independent groups. the friedman test was used to assess the participants at three or more points in time. the wilcoxon signed rank test was used to assess participants on two occasions under two different conditions. furthermore, inter-group and intra-group effect sizes were calculated using cohen’s d formula. the level of confidence for statistical significance was set at 95% (p ≤ 0.05) and the level of clinical significance was set at a “large effect size” (d>0.8). results as previously mentioned, the cg consisted of five males and five females and the hg consisted of six males and four females (table 2). all 20 participants who started the study completed it. the hg completed an average of 2.5±1 sessions in the first week, 2.4±0.8 sessions in the second week, 2.2±1 sessions in the third week and 2.2±1.2 sessions in the final week of the intervention period. (table 3). at pretest the cg oswestry score was 15.4±10.5% (two outliers were present; however, they were included in the statistical analysis) and hg oswestry score was table 5. oswestry lbp scores mean (%) median (%) min (%) max (%) standard deviation 95% ci pre-test oswestry cg 15.4 12.0 10.0 40.0 10.5 7.9-22.9 hg 15.8 16.0 10.0 20.0 4.7 12.5-19.1 post-test oswestry cg 18.0 13.0 4.0 44.0 13.4 8.4-27.6 hg 8.0 8.0 0.0 14.0 3.8 5.3-10.7 four-week follow-up oswestry cg 16.2 12.0 2.0 46.0 13.2 6.8-25.6 hg 8.0 7.0 0.0 33.0 7.7 2.5-13.5 lbp, low back pain; oswestry, modified oswestry lbp disability questionnaire; hg, home-based exercise group; cg, control group; ci, confidence interval; min, minimum; max, maximum table 4. individual sessions completed for home-based exercise group (n=10) participant number week total number of sessions week 1 week 2 week 3 week 4 participant 1. 3 2 3 2 10 participant 2. 2 2 2 1 7 participant 3. 2 3 2 3 10 participant 4. 3 2 3 2 10 participant 5. 2 2 1 2 7 participant 6. 2 1 1 4 8 participant 7. 2 3 1 0 6 participant 8. 5 4 4 4 17 participant 9. 2 3 2 2 9 participant 10. 2 2 3 2 9 table 6. vasp scores mean (%) median (%) min (%) max (%) standard deviation 95% ci pre-test vasp cg 4.7 5 3 7 1.4 3.69-5.71 hg 4.2 4.5 1 7 1.8 2.90-5.50 post-test vasp cg 4.6 3.5 2 8 2.4 2.87-6.33 hg 1.5 1 0 5 1.6 0.37-2.63 four-week follow-up vasp cg 4.0 3.5 2.0 9.0 2.3 2.35-5.65 hg 1.1 1.0 0.0 3.0 1.1 0.31-1.89 vasp, visual analog scale for pain; hg, home-based exercise group; cg, control group; ci, confidence interval; min, minimum; max, maximum original research sajsm vol. 30 no. 1 2018 4 15.8±4.7%. the cg vasp was 4.7±1.4 cm and the hg vasp was 4.2±1.8 cm. the corresponding post-test oswestry scores were as follows: cg 4.6±2.4% and hg 1.5±1.6%, while the vasp results were cg 4.6±2.4 cm and hg 1.5±1.6 cm. at the four-week follow-up the cg oswestry score was 16.2±13.2% and the hg oswestry score was 8.0±7.7%. the four-week follow-up vasp score for the cg was 4.0±2.3 cm and the hg vasp score at the four-week follow-up was 1.1±1.1 cm. the increase in oswestry scores from the post-test to the four-week follow-up test could have been due to the non-compliance of the exercise programme post study. while not significant on a statistical level, “rest’ may have played a role in the reduction of oswestry scores for the cg when comparing pretest to posttest results. (tables 5 and 6). thus following the four-week, home-based exercise intervention, there were significant improvements in the oswestry scores for the hg from the preto the post-test (p=0.005), as well as between the pretest and four-week follow-up test (p=0.021). no significant improvements were observed in the cg between the preand post-test (p=0.095) or between pretest and the four-week follow-up test (p=0.766) for oswestry. large effect sizes were observed in the hg for the oswestry between preand post-test (d=1.8) and between the pretest and the four-week follow-up test (d=1.2). there was also a large effect size (d=1.0) when the hg was compared to the cg at post-test, and a medium effect size (d=0.8) at the four-week follow-up test (tables 7 and 8). significant improvements also occurred in the hg vasp from pre to post-test (p=0.011) and between the pretest and the four-week follow-up test (p=0.005). large effect sizes were observed for the hg between the pre and the post-test (d=1.6) and between the pretest and the four-week follow-up test (d=2.1). there were also large effect sizes when comparing the cg to the hg at post-test (d=1.5) and between the two groups at the four-week follow-up test (d=1.6) (tables 9 and 10). discussion the current study investigated the effectiveness of home-based exercise in treating subacute lbp. the statistically significant improvements in both pain and functional ability reported following four weeks of home-based exercises for participants with subacute lbp were supported clinically by the large effect sizes. in addition, these benefits lasted for at least four weeks after the conclusion of the intervention period, as confirmed by the follow-up test. thus it may be deduced that the home-based exercise programme was a clinically beneficial treatment in the short term (i.e. over eight weeks) for subacute lbp. this may provide an effective alternative treatment for subacute lbp patients who cannot afford or struggle to access supervised rehabilitation. in accordance with previous studies, the intervention programme was designed to strengthen the abdominals, paraspinal muscles, gluteal muscles, hamstrings and multifidi as well as to stretch the erector spinae, hamstrings, hip flexors and quadratus lumborum muscles. [14-19] the current study used a four-week intervention period which compared favourably with that of other studies between four and eight weeks long. [18,19] this study requested that the patients perform the exercises three times per week. this compared favourably with previous studies that implemented exercise programmes between two and five times a week. [18,19] although the compliance of the participants in the current study was favourable, full adherence to the requests of three sessions a week were not followed by all the participants as indicated in table 4. the hypothesis behind the programme was that by stabilising the pelvic and lumbar region through the implementation of strength exercises that table 7. intra-group effect size for oswestry lbp disability questionnaire group test effect size (cohen’s d) cg pre 0.2 post pre 0.0 four-week follow-up hg pre 1.8†† post pre 1.2†† four-week follow-up †† indicates large effect size (d>0.8). lbp, low back pain; hg, home-based exercise group; cg, control group. table 8. inter-group comparison for the oswestry lbp disability questionnaire (%) group test p-value effect size (cohen’s d) cg vs hg pre-test 0.320 post-test 0.022* 1.0†† four-week follow-up 0.081 0.8† * indicates statistically significant difference (p≤0.05); † indicates medium effect size (d>0.5); †† indicates large effect size (d>0.8). lbp, low back pain; hg, home-based exercise group; cg, control group. table 9. intra-group effect sizes for vasp group test effect size (cohen’s d) cg pre 0.1 post pre 0.4 four-week follow-up hg pre 1.6†† post pre 2.1†† four-week follow-up †† indicates large effect size (d>0.8). vasp, visual analog scale for pain; hg, home-based exercise group; cg, control group. table 10. inter-group effect sizes for vasp group test p-value effect size (cohen’s d) cg vs hg pre-test 0.563 post-test 0.003* 1.5†† four-week follow-up 0.002* 1.6†† * indicates statistically significant difference (p≤0.05); †† indicates large effect size (d>0.8). vasp, visual analog scale for pain; hg, home-based exercise group; cg, control group. original research 5 sajsm vol. 30 no. 1 2018 focused on the transverse abdominis, multifidus, hamstrings, gluteal muscles and back extensors pain would decrease, and functional ability improve. furthermore, by combining strength exercises with flexibility that focused on stretching and mobilising the erector spinae, hamstrings, hip flexors and quadratus lumborum muscles, a more successful result would be achieved. the aerobic component of the programme was implemented for a warm-up, as well as to improve lower limb and pelvic stability dynamically. limitations numerous limitations are present in the current study such as, the small sample size, absence of a long-term follow-up assessment, the reduced accuracy of extrapolating the data to rural communities in south africa, lack of education regarding spinal care and correct posture [20], lack of psychological consideration and treatment [21], and levels of activity and fitness prior to the study. the reasoning for overor undercompliance towards the home programme was also not requested. in future studies, researchers should attempt to determine the effects of a longer intervention period, as well as to monitor the longer-term benefits (six months to two years) exercise has on reducing subacute low back pain. monitoring the recurrence of low back pain will be beneficial to fully understanding the prolonged effects exercise rehabilitation has on low back pain. it will be useful if future research also investigates the effects of exercise on subacute low back pain in different age groups, different socio-economic backgrounds and work environments (e.g. bluevs. white-collar workers). furthermore, future studies should look at the prevalence of low back pain in rural settings, as well as approaching low back pain from a multidimensional perspective where the following factors are taken into consideration: modifiable (emotions, behaviours, loading demands, lifestyles etc.), nonmodifiable (social, economic, culture, history and genetics), neuroimmune, endocrine and comorbidity health factors [22]. conclusion the results of the present study confirmed that a four-week home-based exercise programme is effective in improving function and reducing pain in patients with subacute lbp. however, since the study was limited by a small sample size, future studies using larger samples are needed to confirm the present study’s findings. acknowledgements: the authors wish to thank the participants for their contribution to this study. funding: this research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. conflict of interest: the authors have no conflicts of interest to declare. references 1. mcintosh g, hall h. low back pain (acute). bmj clin evid 2011; pii:1102. 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[doi: 10.4085/1062-6050-48.1.16] http://dx.doi.org/10.1136/bjsports-2018-099816 untitled we met our goal of publishing four issues of the journal in 2005. we will try hard to meet this goal again this year. the factor limiting us will be whether sufficient good-quality papers get passed by our peerreview process. one of the criteria of submitted studies that the reviewers are being asked to scrutinise is the precision of the measurements of the outcome variables. this is particularly important in our field of research. scientists having to make decisions about changes in physical performance are always faced with the predicament of deciding whether a change is a real, meaningful change, or whether the change is merely the measurement error associated with the variable that is being studied. for example, how can a decision be made about whether a new pre-race strategy improves 10 km race performance? are changes of the 10 km running performance within the expected variation? the predicament also extends to clinicians who have to decide, for example, whether a change in blood pressure after the intervention of an exercise programme is real, with meaningful clinical consequences, or whether the changes in blood pressure are within the error associated with the measurement of blood pressure. dieticians need to be able to distinguish whether the self-reported dietary intake is different after intervention – to do this they need to know the measurement error of their selfreported measurement. a more intuitive, practical approach to interpreting results has been suggested.1 this approach is based on calculating the confidence intervals around the true difference of the measurement. if the change in the measurement is beyond this confidence interval, then it may be concluded that the invention has a real effect (positive or negative). this approach requires scientists to be more precise about publishing reliability and validity data on their main outcome measurements. the typical error of each measurement also needs to be established. an example of this approach shows that fast runners in crosscountry and road races have a variation in performance of 1.21.9% and in the marathon the variation is 2.6%.2 the variation in the slow runners is almost two-fold higher than for the faster runners. these objective measurements provide the basis for interpreting changes in performance as a result of an intervention. expressing the results this way makes the interpretation of the data more believable. international journals that focus on applied physiology are starting to require this form of data analysis for the studies they accept for publication. this is a common sense approach and one we are going to start applying in our journal. readers are encouraged to familiarise themselves with the methods as described in the cited papers below. this issue of the journal includes a variety of studies. the first study investigated the effects of a single dosage of a nonsteroidal drug (naproxen) and a cyclooxygenase inhibitor (rofecoxib) on the exercise-induced stress response. this study showed that different anti-inflammatory drugs may affect the exercise-induced stress response differently and supports the concept that these drugs should be prescribed with discretion. the study reporting on shoulder injuries in competitive swimmers in kwa-zulu-natal shows that the incidence of such injury is high. this study should act as a catalyst for further mechanistic studies designed to reduce the risk of shoulder injuries in competitive swimmers. the study on the rating of perceived exertion (rpe) for a training session was submitted by the research group that pioneered this subjective method of quantifying the training load. this method is becoming more popular in endurance and team sports. the rpe method is simple and practical and this study shows that the validity and reliability of this tool makes it a sufficiently precise tool to use with confidence. another study examines the biomechanical factors associated with the risk of knee injury when landing from a jump. this is a review paper examining 26 studies that were selected after they met certain criteria. the authors are able to derive conclusions that will direct future mechanistic studies. finally, this issue includes a review paper on c-reactive protein, an acute phase protein that is regulated in response to injury or infection. this concise review is filled with facts and discusses the synthesis, biological properties and functions of c-reactive protein. the next section of the paper links c-reactive protein to cardiovascular disease and acute and chronic exercise training. many of the ideas are novel and provide a good foundation for future studies. may you enjoy reading this issue! mike lambert editor-in-chief 1. batterham am, hopkins wg. making meaningful inferences about magnitudes. sportscience 2005; 9: 6-13. 2. hopkins wg, hewson dj. variability of competitive performance of distance runners. med sci sports exerc 2001; 33: 1588-1592. sajsm vol 18 no. 1 2006 1 editorial measurement error – the missing link? editorial0 3/13/06 2:27 pm page 1 original research 1 sajsm vol. 30 no. 1 2018 concussion knowledge and attitudes amongst stellenbosch university hostel rugby players w j kraak, phd; b a bernardo, ba; h a gouws, bsc; a loubser, ba; j o vuuren, bsc hons; m c coetzee, bsc department sport science, stellenbosch university, stellenbosch, south africa corresponding author: w j kraak (kjw@sun.ac.za) rugby union is a dynamic, high intensity contact sport which can result in numerous injuries to players. of these injuries, concussion and other head injuries make up a fair percentage. [1] mccrory et al. defined concussion as a “complex pathophysiological process affecting the brain, which is well presented in sports such as rugby union and rugby league”.[2] a study by viljoen indicated that rugby players lacked roughly one-third of the necessary concussion knowledge, which may affect their attitudes towards concussion and increase the risks associated with concussion. [3] walker found that sub-elite south african rugby players had a fair knowledge of concussion in terms of identification and diagnosis. [4] players who had a previous history of concussion showed a greater knowledge of this type of injury, thus indicating that knowledge potentially comes from experience rather than from educational programmes. [4] the knowledge of concussion in rugby players can nevertheless have a vital impact on its management and the road to recovery after a player has been concussed. [3] if players have a better understanding of the consequences of concussion and they follow proper protocols, their rate of recovery may drastically improve. [3] viljoen stated that the players themselves can play an essential role in reducing the incidences of concussion and improving the management thereof. [3] in the same study which evaluated the knowledge and attitudes of concussion by junior amateur high school and senior amateur club rugby players, it was found that these players had insufficient knowledge of concussion and their attitudes/behaviours were deemed unsafe. rugby players who understand the severity and effect of concussion and adhere to proper return-to-play guidelines are more likely to have experienced a concussion in rugby themselves and understand the consequences thereof those who are unaware of the severity of concussion need to be educated on the potential consequences of neglecting specific symptoms. [3, 4] to some extent, the players take concussion seriously; however, the mind-set of the players is largely influenced by coaches, fellow teammates and the importance of matches. [4] o’connell and molloy concurred stating that 75% of their participants indicated that they would continue to play in important rugby matches even when concussed. some of the participants in the study also indicated that they would continue playing with a concussion because they did not want to let their teammates down. [5] when looking at hostel rugby at university level, it can be classified as a social league and the players follow less stringent training regimes compared to those followed in professional and international rugby. [6] the lack of physical conditioning for rugby puts the players at risk of injury during training and matches. these injuries include head injuries, of which concussion was found to be one of the top three types of rugby injuries between 2011 and 2013. [6] the relatively high injury risk of hostel rugby may be as a result of the variability in the skills level of the players and the concurrent academic obligations, which may lead to decreased physical and technical conditioning. due to their academic responsibilities, the players are often rotated due to unavailability for certain matches. this may lead to a higher risk of injury because of the lack of practice and game time. [7] the teams in hostel rugby consist of university students who have different levels of skill and conditioning. [7] the reasons are that these players do not have sufficient time to attend the gymnasium, technical and field conditioning sessions apart from the games that are played weekly. [6] in south africa, the aim of the boksmart national rugby safety programme is to provide rugby coaches and referees background: concussion occurs more frequently in contact sports, such as rugby, and is furthermore not fully recognised during play. it is also underreported in the literature, to medical personnel, or to coaches. objectives: the objective of this study was to describe the knowledge about and attitudes towards concussion by stellenbosch university hostel rugby players. methods: the study focussed on gathering quantitative information through implementing a cross-sectional study design. one hundred and eighty stellenbosch university hostel rugby players completed the modified rosenbaum concussion knowledge and attitudes survey student version (rockas-st). the rockas-st questionnaire is divided into three parts, namely, the evaluation of the concussion knowledge index (cki) and concussion attitudes index (cai), and a 16-symptom checklist. results: the participants scored on average 75% in the cki and 81% in the cai. the correlation between cki and cai was r=0.14 which is considered a weak positive correlation. discussion: the participants demonstrated sufficient knowledge of concussion and thus a safer attitude towards concussion. there were some concerning factors from the knowledge of the concussion questions and the symptoms that may have an effect on attitudes towards concussion. conclusion: the study revealed that stellenbosch university hostel rugby players have sufficient knowledge of what constitutes concussion, as well as the necessity of having safe attitude towards it. however, a small number of participants showed that they still may lack knowledge in certain areas concerning concussion. keywords: head injuries; hostel league; university level rugby; survey s afr j sports med 2018;30:1-5. doi: 10.17159/2078-516x/2018/v30i1a4404 http://dx.doi.org/10.17159/2078-516x/2018/v30i1a4404 original research sajsm vol. 30 no. 1 2018 2 with the correct knowledge and technical skills to ensure -that safety and best practice principles are incorporated into all aspects of the game. the boksmart programme has a section that specifically focusses on concussion and its management. based on the above background, the objective of this study was to describe the knowledge of and attitudes towards concussion of the stellenbosch university hostel rugby players. methods this study focused on gathering quantitative information through the implementation of a cross-sectional study design. ethical approval (hrec s16_07_129) was obtained from the research ethics committee: human research at stellenbosch university. hostel rugby players (n=180) from the stellenbosch university took part in the study. one was excluded because of an incomplete questionnaire and another due to the lack of a consent form. the purpose of the study and the procedures of the questionnaire were explained to the participants. those who agreed to participate completed an informed consent form and the questionnaire. the participants completed the questionnaires in person enabling them to ask questions or withdraw from the study at any time during the data collection. the knowledge and attitudes of the participants were measured using a modified rosenbaum concussion knowledge and attitudes survey –student version (rockas-st). [3,8] this survey consisted of three main parts, namely, the concussion knowledge index (cki) , concussion attitude index (cai) and a 16-symptom checklist. it has five sections, where the 16-symptom checklist may form part of the cki, but the cki has its own index. [9] sections one and two examined the participants’ knowledge of concussion, causes and sequelae. [9] section one had 15 true/false questions and section two three true/false questions. [9] questions answered correctly received one point and when answered incorrectly no points. in summary, the scores of section one, two and five were accumulated and the totals ranged from 0-25 to establish the cki. the participant with a higher score in the cki revealed a higher level of the knowledge of concussion. the cai can be used to examine the separate views of all participants. sections three and four consisted of 15 questions, each in a ‘likert scale’ format, ranging from “strongly disagree” to “strongly agree”. [9] out of the 15 questions; five were opinion questions involving the views of the participants and 10 were applied knowledge questions. section five of the rockas-st was replaced with a 16symptom checklist to improve the validity and reliability of the questionnaire. [8] the points received in both sections for each question ranged from one-five points depending on the participant’s response to safety. questions related to safety received one point for a very unsafe response and five points for a very safe response. [9] in summary, the total scores for sections three and four were accumulated and ranged from a total score of 15-75 to establish the cai score. to determine if the response from the participants’ was valid, a validity scale (vs) in section one of the questionnaire was implemented, with three validation questions in true/false format. a completed questionnaire sheet was regarded as invalid if the participant answered nil or only one question correctly out of those three questions. [9] the data were analysed using excel data analysis. descriptive statistics for the questions were reported as frequencies and expressed as percentages, means (m), and standard deviations (sd) in order to summarise the score of each index and the participants’ questions. the correlation between cki and cai was calculated using the pearson correlation coefficient. the shapiro-wilk normality test was used to test normal distribution of data. results the correlation between the cki and cai was r=0.14 and is considered a weak positive correlation. the cki average for the hostel rugby players was 18.8±2.4. the participants answered 75% (18.8±2.4) of the cki questions correctly. this was calculated by dividing their score by a maximum score of 25 (tables 4 and 5). table 1 presents the cki of the participants, where six of the questions were answered correctly by more than 80% of the participants. three of the above-mentioned six questions were answered correctly by more than 90% of the table 1. statements on concussion evaluating the concussion knowledge index (cki) statements n % 1. there is a possible risk of death if a second concussion occurs before the first one has healed. 151 84 2. people who had one concussion are more likely to have another concussion. 135 75 3. in order to be diagnosed with a concussion, you have to be knocked out. 177 98 4. a concussion can only occur if there is a direct hit to the head. 126 70 5. being knocked unconscious always causes permanent damage to the brain. 146 81 6. symptoms of a concussion can last several weeks. 169 94 7. sometimes a second concussion can help a person remember things that were forgotten after the first concussion. 163 91 8. after a concussion occurs, brain imaging (cat scan, mri, x-ray etc.) typically shows visible physical damage (bruise, blood clot) to the brain. 66 37 9. if you receive one concussion and you have never had a concussion before, you will become less intelligent. 162 90 10. after 10 days, symptoms of a concussion are usually completely gone. 78 43 11. after a concussion, people can forget who they are and not recognise others but be perfect in every other way. 70 39 12. concussion can sometimes lead to emotional disruptions. 137 76 13. an athlete who gets knocked out after getting a concussion is experiencing a coma. 33 18 14. there is rarely a risk to long-term health and well-being from multiple concussions. 138 77 n= total number of participants, % =percentage of respondents who answered correctly original research 3 sajsm vol. 30 no. 1 2018 participants. statement 3 was answered correctly as “false” by 98% (n=177) of the participants. statement 6 was correctly answered as “true” by 94% (n=169) of the participants. statement 7 was answered correctly as “false” by 91% (n=163) of the participants. eight of the statements in table 1 were answered correctly by less than 80% of the participants, whereas four of the eight were below 50%. the four most common misconceptions were in statement 13 which was answered correctly as “true” by only 18% (n=33) of 154 the participants. statement 8 was answered correctly as “false” by 37% (n=66) of the participants. statement 11 was answered correctly as “false” by 39% (n=70) of the participants. statement 10 was answered correctly as “true” by 43% (n=78) of the participants. table 2 indicates that the lowest score achieved for the scenarios was the first question, it is likely that player q's concussion will affect his long-term health and well-being, 70% (n=126) of the participants answered correctly. questions two and three had a 98% and 92% respectively correct answer rate. in table 3, the players correctly identified an average of 80% of the symptoms (n=143.75±27.56), whereas an average of 17% (n=31) identified the incorrect symptoms. loss of consciousness, 59% (n=107) and sleep disturbances, 52% (n=93) were the only correct symptoms that scored below 70%. both dizziness and headache had the highest score of 96% (n=173) for the correct symptoms. the highest score for the incorrect symptoms was weakness of the neck’s range of motion, which 44% (n=79) of the players indicated as a symptom. the cai average for the hostel rugby players was 81.28% (60,98±6,32), this being which was calculated by dividing their score by a maximum of 75 (tables 4 and 5). hostel rugby players on average answered 81% of the cai questions correctly. a likert scale was used with a score out of five, where four-five was classified as “safe”, three as “neutral” and onetwo as “unsafe”. table 4 had an average score of 84% that was scored as safe and 10% that was scored as neutral with cai. in table 4, 67% of the participants had a “safe” response where 19% was “neutral” for question 1. in question 2, only 4% of the participants gave a “neutral” answer, which was the lowest, and 93% had a “safe” answer, which was the highest. the scenario with the lowest “safe” percentage of 58%, where most players felt that the athlete who suffered a concussion during the semi-final playoff game should have returned to play during the same game. in another scenario, only 60% of players scored “safe” and it was stated that athletes would feel that the trainer rather than the athlete who suffered a concussion should make the decision about returning athlete to play. comparing the scenario of the player that was concussed during the semi-final game, it was shown that most athletes felt that the athlete who sustained a concussion during the first game of the season should have returned to play during this game and that there was a 21% difference between the scenarios. the first game of the season also had a “safe” score of 79%. discussion the aim of the study was to evaluate and describe the knowledge and attitudes of stellenbosch university hostel rugby players to concussion. the major findings of the study indicated a weak positive correlation (r=0.14) between cki and cai. a weak correlation is 0.1 to 0.3 and a strong correlation is 1.0 to 0.5. a weak correlation means that as the cki increases or decreases, there is a lower possibility of there being a relationship with the cai. the cki mean score achieved by the table 2. scenarios on concussion evaluating the cki scenarios n % 1. it is likely that player q's concussion will affect his long-term health and well-being. 126 70 2. it is likely that player x's concussion will affect his long-term health and well-being. 176 98 3. even though player f is still experiencing the effects of the concussion, his performance will be the same as when he had not suffered a concussion. 165 92 n= total number of participants, % =percentage of respondents who answered correctly table 3. concussion symptoms identification ability the following are symptoms of concussion symptoms n % amnesia (memory loss) 143 79 blurred vision 154 86 confusion 162 90 dizziness 173 96 headache 173 96 loss of consciousness 107 59 nausea 145 81 sleep disturbances 93 502 the following are not symptoms of concussion symptoms n % abnormal sense of smell 7 4 abnormal sense of taste 12 7 black eye 38 21 chest pain 9 5 nosebleed 31 17 numbness/tingling in upper extremity 40 22 sharp burning pain in the neck 32 18 weakness of neck range of motion 79 44 n= total number of participants, % =percentage of respondents who answered correctly table 4. statements on concussion evaluating the concussion attitude index (cai) expressed as a percentage statements safe (%) neutral (%) 1. i would continue playing a sport while also having a headache that results from a concussion 67 19 2. i feel that coaches need to be extremely cautious when determining whether an athlete should return to play 93 4 3. i feel that concussion are less important than other injuries 86 9 4. i feel that athletes has a responsibility to return to a game even if it means playing while still experiencing symptoms of a concussion 89 7 5. i feel that an athletes who is knocked unconscious be taken to the emergency room 85 12 original research sajsm vol. 30 no. 1 2018 4 participants was 18.78 ± 2.44 out of a maximum score of 25. the participants, on average, answered 75% of the cki questions correctly. based on the results of this study, it was found that the participants had a basic knowledge of concussion. in section one of the questionnaire, over 50% of the participants lacked the knowledge of concussion in four questions. this is similar to a previous study done by viljoen, where three of those questions had very similar results ( see table 1 statement 8 and statement 11).[3] this shows that there are areas of concern and misconceptions regarding concussion. in table 3 where participants had to identify the correct symptoms, 59% identified loss of consciousness and 52% indicated sleep disturbances as a symptom. in studies by hecimovich and viljoen sleep disturbances were shown as the lowest correctly identified symptom. [3,10] however, having sufficient knowledge of concussion is not enough, as concussion is a serious matter in sport, specifically rugby. kaut et al. found that the focus should shift from knowledge of concussion to behavioural responses following such injuries. [3] viljoen stated that rugby players can play a crucial part in reducing the incidence of concussion and in improving the management of concussed players. [3] in the viljoen study on the knowledge of concussion in junior amateur high school players and senior club players it was shown that players lacked knowledge of concussion and that their attitudes and behaviours towards concussion were unsafe. [3] the cai average for the participants tested was 60.98 ± 6.34 with a maximum score of 75. on average, the participants answered 81% of the cai questions correctly. this shows that the participants have a good, safe attitude toward concussion but are influenced by parents, teammates, coaches and the importance of specific matches. the above-mentioned statement is supported by studies done by o’connell and molloy and delahunty et al., in which respectively 75% and 73% of the players indicated that they would play with a concussion in important matches. [5, 11] the main reason for wanting to continue was the fear of letting their teammates down. although these factors play a role, a player with a good concussion attitude may still choose to act in an incorrect or unsafe manner following concussion without being influenced. the current study revealed that 58% of the players deemed that playing with a concussion (see table 5 statement 6) as “safe”. if this is compared with another scenario in the questionnaire, it was found that if it was the first game of the season, as opposed to a playoff game, 79% of the players felt that the player should not return to the game. these findings support the claims in the study by o’connell and molloy namely, that players are influenced by important matches. [5] viljoen highlights that there needs to be educational workshops on concussion conducted specifically for rugby players. [3] compared to the study done by viljoen,[3] this present study has shown superior results with regards to concussion knowledge and attitudes. the above-mentioned could be as a result of increased awareness of the dangers of concussion, as well as improved management by coaches and clubs. conclusion in conclusion, the results in this study indicated that stellenbosch university hostel rugby players have sufficient knowledge of what constitutes concussion and a good attitude towards the condition. however, a small number of the players clearly lacked knowledge in certain vital areas of concussion, such as whether a player should play in an important rugby match if suffering from concussion. these vital areas might play an important role in the behaviour of rugby players who sustained the concussion, in terms of avoiding the potential risks of concussion, such as brain damage or even death. for future studies related to concussion, researchers should take note that testing the knowledge and attitudes of concussion on rugby players may be challenging, because there might be a difference between answering a questionnaire and the actual behaviour of players during a match or practice session when referring to concussion. a limitation of the current study was that the content of the questionnaire could have been shared by the different participants thus influencing the other participants in the study. references 1. gardner aj, iverson gl, williams wh, et al. a systematic review and meta-analysis of concussion in rugby union. sports med 2014;44(12):1717-1731. [doi: 10.1007/s40279-014-0233-3] 2. mccrory p, meeuwisse wh, aubry m, et al. consensus statement on concussion in sportthe 4th international conference on concussion in sport held in zurich, november 2012. j sci med sport 2013;16(3):178-189. [doi: 10.1016/j.jsams.2013.02.009] table 5. scenarios on concussion evaluating the concussion attitude index (cai) expressed as a percentage scenarios safe (%) neutral (%) 1. i feel that coach a made the right decision to keep player r out of the game. 94 3 2. most athletes would feel that coach a made the right decision to keep player r out of the game. 70 16 3. i feel that athlete m should have returned to play during the first game of the season (that same game of the injury). 90 5 4. most athletes would feel that athlete m should have returned to play during the first game of the season (that same game of the injury). 79 13 5. i feel that athlete o should have returned to play during the semi-final playoff game. 86 9 6. most athletes feel that athlete o should have returned to play during the semi-final playoff game. 58 20 7. i feel that the athletic trainer rather than athlete r should make the decision about athlete r returning to play. 78 9 8. most athletes would feel that the athletic trainer rather than athlete r should make the decision about returning athlete r to play. 60 24 9. i feel that athlete h should tell coach about the symptoms. 93 5 10. most athletes would feel that athlete h should tell coach about the symptoms. 67 24 original research 5 sajsm vol. 30 no. 1 2018 3. viljoen ct, m schoemman, c brandt, et al.. concussion knowledge and attitudes among amateur south african rugby players. s afr j sports med 2017;29(1):1-6. [doi: 10.17159/2413-3108/2015/v27i2a492] 4. walker sp. concussion knowledge and return-to-play attitudes among subelite rugby union players. s afr j sports med 2015;27(2):50–54. [doi: 10.7196/sajsm.536] 5. o’connell e, molloy mg. concussion in rugby: knowledge and attitudes of players. ir j med sci 2016;185(2):521-528. [doi: 10.1007/s11845-015-1313-6] 6. barret a. the epidemiology of hostel rugby injuries at stellenbosch university. unpublished msc (sport science) thesis. stellenbosch: stellenbosch university, 2015. 7. mathewson e, grobbelaar r. tackle-injury epidemiology in koshuis rugby players at stellenbosch university. s afr j sports med 2015;27(3):72–75. [ doi:10.7196/sajsm.8091] 8. williams j. concussion knowledge and attitudes in english football (soccer). unpublished m.s. (kinesiology). georgia: georgia southern university, 2013. 9. rosenbaum am, arnett pa. the development of a survey to examine knowledge about and attitudes toward concussion in high-school students. j clin exp neuropsychol 2010;32(1):4455. [doi: 10.1080/13803390902806535] 10. hecimovich m, king d, marais i. player and parent concussion knowledge and awareness in youth australian rules football. the sport journal 2016. http://thesportjournal.org/article/player-and-parentconcussion-knowledge-and-awareness-in-youth-australianrules-football/. [accessed 1 june 2017] 11. delahunty sp, delahunt e, condon b, et al. prevalence of and attitudes about concussion in irish schools' rugby union players. j sch health 2015;85(1):17-26. [doi: 10.1111/josh.12219] 12. kaut kp, depompei r, kerr j, et al. reports of head injury and symptom knowledge among college athletes: implications for assessment and educational intervention. clin j sport med 2003:13(4):213-221 http://thesportjournal.org/article/player-and-parent-concussion-knowledge-and-awareness-in-youth-australian-rules-football/ http://thesportjournal.org/article/player-and-parent-concussion-knowledge-and-awareness-in-youth-australian-rules-football/ http://thesportjournal.org/article/player-and-parent-concussion-knowledge-and-awareness-in-youth-australian-rules-football/ original research 1 sajsm vol. 30 no. 1 2018 a cross-sectional study of 2550 amateur cyclists shows lack of knowledge regarding relevant sports nutrition guidelines i m sparks1, mbchb, d c janse van rensburg1, md, l fletcher2, phd, a jansen van rensburg1, msc 1institute for sport exercise medicine and lifestyle research & section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 2department of statistics, faculty of natural and agricultural sciences, university of pretoria, south africa corresponding author: d c janse van rensburg (christa.jansevanrensburg@up.ac.za) nutritional guidelines for sports endurance events suggests the following factors are important in the days before, and the day of the race: optimising muscle glycogen content and hydration status pre-event, carbohydrate feeding and fluid replacement during the event, and the role of supplements (sports foods/drinks and ergogenic aids) for enhancing competition performance.[1] therefore the authors sought to understand how amateur cyclists (i.e. any cyclist not receiving monetary or apparel support from an outside source), understood and interpreted these guidelines. nutritional supplements receive much attention[2,3] with manufacturers pitching the market to accentuate their additional value to health and performance.[4,5] the use of dietary supplements is widespread among athletes.[2] many amateur and professional athletes may be influenced by the overwhelming industry presence and advertising appeal regarding sports supplementation. in an attempt to enhance and gain an additional performance edge beyond the effects obtained through training, these athletes may consider the use of dietary supplements or engineered foods.[2,3] athletes may also receive advice from many well-meaning supporters and friends. the scientific evidence in support of these claims is often vague, and it makes the use of the substance controversial and confusing. this leaves the athletes, and especially the amateur athletes, vulnerable to misinformation and risk in terms of the safety, validity, and efficacy of dietary supplements.[3] carbohydrate (cho) usage before, during and after endurance events has received ample attention and scrutiny in the past.[1,4] it has been confirmed that cho intake plays an intricate role in optimising glycogen storage in muscle before exercising, during, and in the rapid replenishment of muscle glycogen after exercise.[1,4] various guidelines[5,6] are suggested in scientific and non-scientific literature for carbohydrate use before, during and after an event. the question remains whether amateur cyclists adhere to nutritional guidelines, or if they are oblivious to the fact that nutritional dose adherence may enhance their performance and delay fatigue? recent reports comparing masters and younger triathletes’ postexercise dietary practices [7,8], suggest that both have poor knowledge of recommendations for post-exercise carbohydrate intakes, and that the low intakes of carbohydrate and protein by masters athletes may impair acute recovery.[7,8] this may also hold true when comparing males vs. females.[7,8] the role hydration strategies play before, during and after exercise is also supported by the literature.[9,10] recommended general hydration guidelines include starting to exercise hydrated and drinking sufficiently during exercise (to prevent > 2-3% loss of initial body weight) to avoid dehydration. drinking strategies should be adjusted individually to sweat loss and sweat electrolyte content [9,10] and exercise duration. it is recommended that endurance athletes strive to start all exercises well hydrated, that athletes should drink according to thirst and maintain a pale urine colour.[9,10] the momentum 94.7 cycle challenge in south africa is a 94.7 km fast circular road race, and the world's second-largest individually timed cycle event after the cape town cycle tour, with 27 000 to 35 000 cyclists entering annually. the age, sex, background: amateur cyclists use a wide variety of supplements and nutritional substances to increase performance in addition to their training. objectives: the intended nutritional supplement use, carbohydrate (cho) use and hydration practices of amateur cyclists before, during and after endurance cycling were analysed. evidence of ignorance regarding the use of sports supplements and cho, as well as the disregard of hydration strategy was hypothesised. methods: amateur cyclists, of all age and sex groups, were requested to complete an online survey anonymously on the 2013 momentum 94.7 cycle challenge website, a few days before the event. results: responses were received from 2 550 out of 30 640 race entrants (8%); representing a distribution of 75% males, 25% females, with the majority between 25 to 45 years old. nutritional supplements were used by 59% of respondents, with 77% dose adherence, and 29% with supplement ingredient knowledge. half of the respondents (48%) planned to carbo-load two-three days before the event, while only five percent used professional advice to scientifically calculate their carbo-loading requirements. cho were consumed by 81% during the event. hydration preferences during the race were sports drinks (59%) and water (22%); and after the race 45% preferred a sports drink and 40% water. ingredients, taste, colour, and temperature were criteria used to choose a sports drink. only 18% of respondents knew to use both colour of urine and thirstiness to determine post-race fluid requirements. conclusion: the authors concluded that amateur cyclists had insufficient knowledge regarding nutritional supplement ingredients and usage, cho requirements and carbo-loading practices, and hydration strategies before, during and after the event. keywords: ergogenic aids, nutritional supplements, carbohydrate use s afr j sports med 2018;30:1-6. doi: 10.17159/2078-516x/2018/v30i1a2963 mailto:christa.jansevanrensburg@up.ac.za http://dx.doi.org/10.17159/2078-516x/2018/v30i1a2963 original research sajsm vol. 30 no. 1 2018 2 race experience and health status of participants is varied. the aim of this study was to determine amateur cyclists’: 1) nutritional sports supplement knowledge and use, 2) carboloading and usage, and 3) hydration practices before, during and after an endurance event. males and females were also compared regarding their supplement knowledge and use, and carbo-loading practices. it was hypothesised that there is evidence of ignorance in amateur cyclists regarding sports supplement use, carbo-loading and hydration strategies, during an endurance event participation. methods participants all 30 640 cyclists who entered the 94.7 km road race during the 2013 momentum cycle challenge in johannesburg, south africa, were invited to partake in this cross-sectional study prior to the event. the momentum 94.7 cycle challenge is an annual one-day fast circular route, 1794m above sea level, an elevation range between 1316 m and 1790 m, and a gain of 741 m. the race has one category 2 climb, one category 3 climb, and two category 5 climbs. this one-day cycle challenge takes place during november, which ensures hot and humid racing conditions. participants are widespread in terms of age, sex, race experience and health status. starting time is staggered in blocks of ±300 cyclists per block. cyclists are allocated to different starting times depending on their seeding. questionnaire the questionnaire was developed by a panel of subject experts to assess the planned supplement, nutritional, and hydration strategies during the 2013 momentum 94.7 cycle challenge. the event organisers were approached via email on using the participants for research purposes and permission was obtained to invite volunteers who wanted to be part of the research. the questionnaire was posted online on the momentum 94.7 cycle challenge website a few days prior to the event. the objective of the questionnaire was explained on the website. all cyclists could complete the survey anonymously and had the option to quit the survey at any stage. only complete questionnaires (n=2 550) were included in the analysis. professional cyclists were excluded. a survey with questions and answer options to determine the amateur cyclist’s knowledge regarding nutritional supplement use, carbo-loading and hydration strategies, before, during and after an endurance race was introduced. the questionnaire was comprised of four parts:  demographic data in terms of age and sex were collected,  nutritional supplement (any supplement) usage and knowledge were collected (reasons for use, dose adherence, and knowledge of ingredients) via a dropdown list with an open-ended option,  carbo-loading and cho-usage were examined (reasons for use, reason for not carbo-loading, type of cho used before, during and after the race, and if cho requirements were calculated or guessed),  hydration knowledge and habits were appraised (the frequency of fluid intake, their preferred type of drink during the race, the type of drink and fluid needs after the race). the ethics committee at the faculty of health sciences of the university of pretoria approved the protocol for the study. consent to participate in the momentum 94.7 cycle challenge, as well as completing the research study questionnaire, was obtained during online race entry by the race organisers. parents of children aged 12-18 years were requested to give consent to be part of the research study at the time of the online entry for the race. data analysis data were analysed using ibm spss statistics version 22. the data set was summarised univariately, as well as bivariately by age and sex, to gain insight into participants’ habits and levels of usage and knowledge. chi-square tests (2) were performed to assess interactions between males and females with regard to supplement usage and knowledge, as well as carbo-loading. in the case of significant results, the adjusted residual is reported and the expected frequencies under the null hypothesis of no interaction compared to the observed counts to facilitate interpretation of the interactions. results demographics the demographics of the cyclists’ age and sex are reported in table 1. the response rate was 8% (75% male and 25% female), which represented the overall race demographics of 77% male and 23% female entrants. the largest response to the nutritional questionnaire came from the 25-45 year age group. supplement usage nutritional supplement usage was indicated by 61% of the respondents. as seen in figure 1, the main reason for supplement usage was to aid in recovery (45%), followed by being recommended by either a friend (35%), or a dietician (18%). another popular reason for supplement usage was the cyclists’ concern regarding insufficient training (15%). table 1. demographics of race entrants vs. questionnaire respondents divided by age groups and sex all race entrants (n=30 640) questionnaire respondents (n=2 550) age groups n (%) n (%) 12-18 years 1 057 (3) 5 (0.2) 19-24 years 2 020 (7) 117 (5) 25-30 years 4 835 (16) 368 (14) 31-35 years 4 656 (15) 378 (15) 36-40 years 5 019 (16) 380 (15) 41-45 years 4 742 (15) 414 (16) 46-50 years 3 438 (11) 327 (13) 51-55 years 2 434 (8) 251 (10) 56 years + 2 439 (8) 310 (12) sex n (%) n (%) female 7 192 (23) 641 (25) male 23 448 (77) 1909 (75) n= total number of participants, % = proportional frequency of participants in each category age group categories: indicated as received from the momentum 94.7 cycle challenge race organisers. original research 3 sajsm vol. 30 no. 1 2018 advertising did not seem to play a prominent role in their decision-making. dose adherence as stated on the packaging label or pamphlet was followed by 75% of athletes. only 2.5% admitted to taking more than the recommended dosage specified. there was a significant interaction between males and females with regard to nutritional supplement usage (2(1) = 4.681, p = 0.031; adjusted residual = -2.2). interestingly, fewer females used nutritional supplements than was expected under the null hypothesis of no interaction. there was no significant interaction between males and females regarding their knowledge of supplement ingredients (2(1) = 0.102, p = 0.749). almost half (47%) of respondents were familiar with the ingredients in their sports supplement. ingredients frequently selected by this sample of athletes were cho, caffeine, whey protein, amino acids, magnesium and vitamin c. cho-intake strategies approximately two-three days prior to the race, 48% of respondents deliberately intended to carbo-load. there was no significant interaction between males and females with regard to carbo-loading habits (2(1) = 0.437; p = 0.509). more than half of the participants in the 25-30 year age group used carboloading. in all other age groups less than half of the participants used carboloading. however, there was no significant difference (p = 0.709) between any of the age groups (figure 2). of the 52% respondents who did not carbo-load prior to the event, they claimed that the main reason therefore fig. 1. reasons for supplement use, and source of information. (respondents could select multiple reasons for using supplements.) 45% 53% 50% 46% 48% 48% 46% 44% 0 50 100 150 200 250 300 350 400 450 19-24 25-30 31-35 36-40 41-45 46-50 51-55 56+ n u m b e r o f r e sp o n d e n ts fig. 2. proportion of participants in each age group who indicated to cho-loading prior to the event (n= 2545). (<18 years omitted due to small sample size.) 63% 43% 31% 22% 18% 11% 7% 6% 6% 0 200 400 600 800 1000 1200 1400 1600 1800 n u m b e r o f r e sp o n d e n ts fig. 3. preferred source for cho-replacement during the race. (respondents could select multiple choreplacement sources.) n u m b e r o f r e sp o n d e n ts original research sajsm vol. 30 no. 1 2018 4 was that they did not need it (69%), followed by the fear of weight gain (16%), and lastly, experiencing gastrointestinal tract (git) side effects (12%). during the race, 81% of the cyclists planned to use a cho preferably as a sports drink, sports gel or sports bar (figure 3), while whole food choices, for example, sweets, fruit, sandwiches and potatoes were less preferred. after the race, cyclists preferred the cho to be a sports drink, or part of a meal. most of the cyclists who carbo-loaded (35%) used the formula given on their product packaging (not taking body weight into account). athletes took their carbo-loading advice from a friend (28%), and others obtained their advice from sports magazines (11%) and the internet (20%), respectively. only 5% of the cyclists reported that they made use of professional advice and calculated their carbo-loading according to a nutritional scientific formula based on their body weight (8-12g cho/kg body weight/day). there was no statistical significant difference (p = 0.116) between age groups regarding methods used to calculate cho requirements (figure 4). there was no significant interaction between males and females with regard to carbo-loading requirement knowledge (2(2) = 0.2861, p = 0.8667). hydration strategies the frequency of fluid intake during the race was as follows: 38% of respondents planned to drink fluids every 15 minutes and 28% every 30 minutes. the preferred fluids during the race were a sports drink (59%), and water (22%). the criteria used to choose a sports drink were based on ingredients (29%), taste (28%), and on a friend’s recommendations (19%). with regard to ingredient knowledge, the most sought-after ingredients preferred by the cyclists in their sports drink, were electrolytes (33%), cho (27%), vitamins and minerals (16%), and proteins (12%). half of the respondents (55%) did not know the percentage of cho in their preferred sports drink, and 43% did not know the type of cho. after the race, 45% preferred a sports drink and 40% water as their choice of fluid. only 18% of respondents were aware of using both the colour of their urine and their feeling of thirst to determine their post-race fluid requirements. discussion this study investigated the intended use of supplements, cho and hydration strategies by amateur cyclists participating in a 94.7 km one day endurance cycle event. the participants that responded to the online nutritional questionnaire were representative with regard to age and sex. the main findings of this research showed that the majority of respondents used supplements (59%) and adhered to the dose (77%), although only 29% were familiar with the specific ingredients in their preferred sports supplement. half of the respondents carbo-loaded, but a mere 5% used professional advice to scientifically calculate their requirements. the main reasons given for not carbo-loading were ignorance, fear of gaining weight and git side effects. hydration preferences during and after the race were a sports drink and water respectively. only a few respondents knew to use the colour of their urine and the feeling of thirst to determine post-race fluid requirements. research on the supplement use strategies of professional athletes[2] is more often reported than in recreational athletes.[11] most studies confirmed that athletes, regardless of sex and age, do use supplements.[1,2,3] the main reasons for professional athletes taking supplements were enhanced recovery and greater muscle strength,[12] whereas a study by morrison compiled on recreational supplement users indicated the reasons for taking supplements varied considerably.[13] the use of supplements and the reasons given for their usage corresponds to the findings in this study on recreational cyclists. this study also found that most of the athletes adhered to the dose as indicated on the package insert, while a few admitted to increasing the recommended dose specified. contrary to this study’s findings, a previous study on commercial gym users indicated that the majority of them get information regarding the use of supplements from magazines (66%), family or friends (63%), health food store staff (56%), books (55%), the media (46%), and personal trainers (39%). only a small number of the abovementioned athletes visited a physician (34%), dietitian (28%) or pharmacist (17%) for advice on the supplements they use, which is in agreement with the findings of this research.[13] with information being readily available, consumers are expected to be more aware, educated and health conscious about the supplements they use. however, this present study revealed that only 29% of respondents have an adequate knowledge of supplement 73% 81% 81% 72% 77% 78% 78% 72% 0 50 100 150 200 250 300 350 400 450 19-24 25-30 31-35 36-40 41-45 46-50 51-55 56+ n u m b e r o f r e sp o n d e n ts fig. 4. proportion of respondents who indicated not-scientifically calculating their cho requirements (n= 2545). (<18 years omitted due to small sample size.) original research 5 sajsm vol. 30 no. 1 2018 ingredients, confirming the need for more appropriate education in this regard. the authors found a significant interaction between males and females, with fewer females reporting the use of nutritional supplementation during the 94.7 km momentum cycle challenge. this is in accordance with a study conducted in canada on university students that found only 51% male athletes and 43% female athletes used a protein supplement, while in the non-athletic group only 23% males and 17% females used protein supplements.[12] numerous studies have been done on carbo-loading techniques to validate the ergogenic possibilities of various methods and the duration of loading.[1,4-6] research indicates that many athletes who attempt to carbo-load fail to achieve their goal.[7,8] therefore many opt not to carbo-load, as proven by the majority of respondents in this study that did not plan to carbo-load before this event. carbo-loading also causes a body mass increase of approximately two kg, and additionally, it is important to have high-cho, low-fibre, and low-fat foods.[14] this present study revealed that 16% of respondents opted not to carbo-load for the fear of weight gain, and 12% due to experiencing git side effects. this again highlights the need for nutritional education in this regard. during exercise, low levels of muscle glycogen or blood glucose may be contributing factors in the premature onset of fatigue.[4,6] consuming cho before and during prolonged exercise may help to delay exhaustion during endurance events.[4-6] generally, the regular muscle glycogen stores of elite and amateur athletes are sufficient to sustain exercise duration of up to 60–90 minutes. however, in longer lasting events of intermittent high-intensity exercise lasting more than 90 minutes, athletes may experience fatigue due to exhaustion of muscle glycogen stores.[4-6] birkenhead and slater[15] noted that the food choices athletes make are motivated by taste, convenience, nutrition knowledge and beliefs, and are also influenced by physiological, psychological, social and economic factors. the 81% respondents in this present study that planned to use a cho during the race, preferred cheap, convenient, and readily available sources. a study by hottenrott et al.[16] investigated athletes’ selfchosen dietary strategies compared to a scientifically formulated strategy, in relation to their performance. they concluded that performance was better in the group that used scientific dietary strategies. although more than a third of the cyclists carbo-loaded according to the formula given on their product packaging, few of the respondents in this study calculated their carbo-loading requirements according to the formula of a dietitian or doctor. this correlates with results from a study done on non-elite multisport endurance athletes, which concluded that many of the athletes do not meet the current recommendations for carbo-loading during an event, emphasising the need for better targeted nutritional education.[7, 8] less than a third (27%) of the momentum 94.7 cycle challenge cyclists examined the cho content of their sports drinks. although current research[4-6] suggests that 6-10% cho solutions and hydration solutions containing multipletransportable cho may be effective for athletes who need cho replacement during exercise, only half of the respondents in this study knew the percentage of the cho in their preferred sports drink, and less than half of the respondents knew the type of cho in their chosen sports drink. contrary to expectations by the athlete, their lack of knowledge may lead to ineffective carbohydrate replacement.[7,8] electrolytes were the most sought-after ingredient (33%) in selecting a sports beverage in this study. it has been proven that electrolyte replacement is generally not needed during shortterm exercise. it may, however, be beneficial during very lengthy exercise periods, or if the athlete has a high sweat rate.[9,10] in this study, proteins were one of the ingredients the cyclists regarded essential in their sports drink. the past few decades have seen an evolution in fluid intake guidelines for endurance and ultra-endurance events.[9,10] the recommended strategies have changed from encouraging to drink as much as possible, to drinking only when thirsty. the frequency of fluid intake in this study, as indicated by the cyclists, was quite high. unfortunately, volume was not considered, thus limiting the discussion on hydration. further limitations to this study include the questionnaire being non-compulsory to all participants in the momentum 94.7 cycle challenge, and although the response rate represented the overall event demographics, it was only completed by individuals prepared to make the effort. recall bias based on memory recollection of the participants may also have played a role in the response to questions. furthermore, an interesting future focus will be to include the performance level of the cyclists to determine whether those participating at a higher level have a different level of knowledge, which is a current shortcoming in this study. conclusion it seems that amateur cyclists participating in the 2013 momentum 94.7 cycle challenge have inadequate knowledge regarding the supplements they prefer using, as well as wideranging carbo-loading and cho-usage habits. they also have insufficient knowledge regarding optimal hydration strategies. there is thus a real need for education regarding supplement usage and knowledge, cho ingestion habits and hydration practices, in amateur cyclists. acknowledgements: the questionnaire was funded by momentum, one of the sponsors of the momentum 94.7 cycle challenge. authorships: study design: dr i m sparks and prof d c janse van rensburg. data collection: via electronic questionnaire. data analysis: dr l fletcher. data interpretation and manuscript preparation: dr im sparks, prof dc janse van rensburg, dr l fletcher and a jansen van rensburg. declarations: all authors approved the final version of the paper, and have no conflict of interest to declare. statement: the protocol was approved by the ethics committee of the university of pretoria, south africa. original research sajsm vol. 30 no. 1 2018 6 references 1. thomas dt, erdman ka, burke lm. american college of sports medicine joint position statement. nutrition and athletic performance.med sci sports exerc 2016;48(3):543-568. [doi: 10.1249/mss.0000000000000852] 2. knapik jj, steelman ra, hoedebecke ss, et al. prevalence of dietary supplement use by athletes: systematic review and meta-analysis. sports med 2016;46(1):103-123. [doi: 10.1007/s40279-015-0387-7] 3. buell jl, franks r, ransone j, et al. national athletic trainers' association position statement: evaluation of dietary supplements for performance nutrition. j athl train 2013;48(1):124-136. [doi: 10.4085/1062-6050-48.1.16] 4. beelen m, cermak nm, van loon lj. performance enhancement by carbohydrate intake during sport: effects of carbohydrates during and after high-intensity exercise. nederlands tijdschrift voor geneeskunde. 2015;159:a7465. 5. mayo jj. carbohydrate intake for peak performance: practical guidelines for the endurance athlete. amaa journal 2015;28(3):8-11. 6. jeukendrup ae. periodized nutrition for athletes. sports med 2017;47(suppl 1):51-63. [doi: 10.1007/s40279-017-0694-2] 7. masson g, lamarche b. many non-elite multisport endurance athletes do not meet sports nutrition recommendations for carbohydrates. appl physiol nutr metab 2016;41(7):728-734. [doi: 10.1139/apnm-2015-0599] 8. heikura ia, stellingwerff t, mero aa, et al. a mismatch between athlete practice and current sports nutrition guidelines among elite female and male middle-and long-distance athletes. int j sport nutr exerc metab 2017;27(4):351-360. [doi: 10.1123/ijsnem.2016-0316] 9. armstrong le, johnson ec, mckenzie al, et al. ultraendurance cycling in a hot environment: thirst, fluid consumption, and water balance. j strength cond res 2015;29(4):869-876. [doi: 10.1519/jsc.0000000000000822] 10. american college of sports medicine, sawka mn, burke lm, et al. american college of sports medicine position stand. exercise and fluid replacement. med sci sports exerc 2007;39(2):377-390. [doi: 10.1249/mss.0b013e31802ca597] 11. tsitsimpikou c, chrisostomou n, papalexis p,et al. the use of nutritional supplements among recreational athletes in athens, greece. int j sport nutr exerc metab 2011;21(5):377-384. 12. kristiansen m, levy-milne r, barr s, et al. dietary supplement use by varsity athletes at a canadian university. int j sport nutr exerc metab 2005;15(2):195-210. 13. morrison lj, gizis f, shorter b. prevalent use of dietary supplements among people who exercise at a commercial gym. int j sport nutr exerc metab 2004;14(4):481-492. 14. potgieter s. sport nutrition: a review of the latest guidelines for exercise and sport nutrition from the american college of sport nutrition, the international olympic committee and the international society for sports nutrition. s afr j clin nutr 2013;26(1):6-16. 15. birkenhead kl, slater g. a review of factors influencing athletes’ food choices. sports med 2015;45(11):1511-1522. 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[doi: 10.1139/h2012-028] https://doi.org/10.1249/mss.0b013e31802ca597 pg64-70.indd introduction rugby union is played in more than 100 countries across 5 continents by more than 3 million people between the age of 6 and 60. 14,15 in south africa, a reported total of 326 565 rugby players are currently participating in club and school rugby matches. 38 as with any contact sport, rugby union has a high risk of injury. the incidence of match-related injuries is much higher than in other popular south african team sports. a total of 218 and 120 ‘time-loss’ injuries per 1 000 hours of player exposure during matches have been reported for international and club rugby respectively. 2 soccer and cricket have a much lower incidence of injuries, with international and club soccer resulting in 42 and 26 injuries respectively per 1 000 hours of player exposure during matches and international and club cricket resulting in 2.8 and 1.8 injuries respectively per 1 000 hours. 2 the majority of injuries result from contact phases of play such as the tackle, taking the ball into contact, the scrum, the ruck and maul and the lineout. 1,6 although the tackle situation has demonstrated the majority of injuries in south african schoolboy (55%) 33 and senior rugby players (40%), 3 the scrum carries a 60% greater risk per event. 6 injuries to the head and neck resulting in permanent (>12 months) severe functional disability, which have recently been defined as ‘non-fatal catastrophic injuries’ 6 are unfortunately also a part of the game. 25 head and non-fatal catastrophic neck injuries have been shown to range from 12% to 33% of all injuries. 1 a 2001 analysis 30 of published cervical spine injury data reported distributions of catastrophic cervical spine injuries in specific phases of play. the scrum resulted in 40%, the tackle resulted in 36%, the ruck and maul in 17% and other phases only resulted in 6% of catastrophic cervical spine injuries. during recent years the incidence of head and cervical spine injuries has caused huge concern to the medical fraternity. 1,12,1820,25,30,31,36,40 measures to reduce the number of catastrophic injuries have included law changes and educational initiatives. 25,30,31 laws governing the scrum, including scrum engagements, and the tackle have been adapted to make the game safer and to avoid non-fatal catastrophic injuries to the cervical spine. 16,25,30 examples of rule changes introduced to reduce the incidence of catastrophic injuries include the crouch-touch-pause-engage sequence of scrum engagement and the outlawing of the high and spear tackles. a recent evaluation 31 of a national injury prevention programme (the new zealand rugbysmart programme) in rugby union showed that its introduction has coincided with a reduction in the rate of disabling spinal injuries. since the introduction of the programme in 2001 the incidence of scrum-related spinal injuries decreased from the predicted number (based on the injury rates of previous periods) of 19 to 8. similarly, injuries resulting from tackles, rucks and mauls decreased from the predicted number of 9 to 7. this study demonstrates the benefit of teaching safe and effective techniques in rugby. the need for coaches to emphasise correct technique is extremely important and one of the few possible modes to reduce injuries, especially non-fatal catastrophic injuries to the head, neck, brain and spine. the purpose of this paper is not only to provide evidence of safe techniques during the contact phases of the game (tackling, taking ball into contact, scrum setting and engagement, lineouts as well as rucks and mauls), but also to provide empirical evidence that safe technique is effective technique. coaches are thus able to ensure greatest safety to their players while improving their technical effectiveness. commentary boksmart: safe and effective techniques in rugby union abstract as with any contact sport, rugby union has a high risk of injury. the majority of injuries result from contact phases of play such as the tackle, taking the ball into contact, the scrum, the lineout and the ruck and maul. many techniques associated with a reduced risk of injury can be taught. the need for coaches to emphasise correct technique is extremely important and one of the few possible modes to reduce injuries, particularly non-fatal catastrophic injuries to the head, neck, brain and spine. this paper provides evidence of safe techniques during the contact phases of the game (tackling, taking the ball into contact, scrum setting and engagement, lineouts as well as rucks and mauls). examples are also given to show that safe techniques often are the most effective techniques from a performance perspective. correspondence: michael posthumus uct/mrc research unit for exercise science and sports medicine department of human biology, university of cape town sport science institute of south africa boundary road newlands 7700 south africa tel: 27-21-650-4572 fax: 27-21-650-7530 e-mail: michael.posthumus@uct.ac.za michael posthumus (bsc(med)(hon) exercise science)1 wayne viljoen (phd)2 1 uct/mrc research unit for exercise science and sports medicine department of human biology, university of cape town 2 manager: boksmart national rugby safety programme 64 sajsm vol 20 no. 3 2008 pg64-70.indd 64 10/22/08 10:48:12 am tackling in studies reporting the incidence of rugby union injuries, tackling has been shown to be the cause of 25% and 14% of injuries in schoolboy and adult south african rugby players respectively. 3,33 the most frequent body sites injured during tackling (injuries to the tackler) were the upper limb (35%), including the shoulder and clavicle; the head, neck and face (28%); and the lower limb (27%). 41 it has been reported that the injury with the highest incidence in tackling is a cervical nerve root injury for forwards and concussion for backline professional rugby players. 1 these results are in agreement with previously reported injuries in south african schoolboys, which similarly demonstrated a large proportion of tackle injuries to the head and neck. 33 roux et al. 33 also reported concussion to account for 14% of injuries incurred while tackling. tackle injuries were most often associated with front-on tackling, rather than tackling from the side or from behind. 32,41 the tackle has been shown to be the major contributor to serious catastrophic cervical spine injuries (36% of all reported non-fatal catastrophic cervical injuries). 30 trauma to the cervical spine may occur during tackling through vertex impacts and hyperflexion. 25 although the mechanism of cervical spine tackle injuries has not been substantially reported in rugby union, it has been proposed to be a result of hyperflexion of the neck. 25,30 the mechanism of catastrophic cervical spine injuries as a result of tackling in american football has however been very well researched and documented. 12 axial loading which occurs during contact with the top or crown of the head or helmet (referred to as spear tackling in american football) is the primary mechanism of catastrophic spinal injuries in american football. 12 non-fatal catastrophic cervical spine injuries, which occur during tackling caused by both mechanisms described above, are avoidable through coaching and implementing safe and effective technique. a general lack of skill from the tackler has been highlighted as a risk factor to catastrophic cervical injuries and concussion, 9,25,30 and as the primary reason for a much higher rate of tackling injuries sustained among schoolboys. 3 it is therefore important, especially at lower levels, to emphasise the basics of safe and effective tackling technique. primary emphasis should be placed on the head and neck position in the tackle. most importantly, players should be coached to place their heads in the safest area when tackling, e.g. placing the head behind the buttocks of the ball carrier, and to ensure that the face is always up when performing a side-on tackle. the cervical spine is able to dissipate forces by controlled spinal motion through the paravertebral muscles, eccentric contractions and intervertebral discs. 39 when the natural lordosis (curve) of the cervical spine is lost, due to head-down contact, the forces generated by contact to the top of the head are transmitted along the vertical axis of the spine and can no longer be dissipated. 12 it is under these conditions in which the spine fails in a flexion mode, resulting in fracture which may sever the spinal cord and cause instant paralysis. 25 forced hyperflexion from entering the tackle with the head flexed may also result in a similar vertebral dislocation or fracture and subsequent catastrophic cervical injury. ex vivo laboratory experiments of the cervical spine have presented evidence to suggest that the cervical spine is able to bear the greatest axial forces when in the natural lordotic position. 26,27 loss of lordosis has been shown to increase the risk of cervical spine injuries. 27 this principle also applies to the thoracic and lumbar vertebrae, when the flexed and twisted spine is less able to resist applied axial torques. thus a loss of spinal lordosis may also increase the risk of torsional injury. 21 although the tackler’s anatomical site of contact should always be the shoulder, safety must be ensured by keeping the face up and focussed on the core of the approaching ball-carrier. the spine should also always be in its strongest position of resisting front-on axial forces and sideways axial torques, and thus a tackle should always be performed with a neutral straight spine with natural lordosis (spine in line) with the tackler’s shoulders above the hips. this position will not only reduce the risk of injury but also produce greater force development and thus improve the effectiveness of the tackle. contrary to what is often believed, approaching the tackle halfheartedly may in fact place the tackler at greater risk of injury. greater differential impact between the tackler and the person being tackled seems to be a major risk factor for injury to the player with lower momentum. 9 this emphasises the need to dominate the tackle situation, and it has been suggested that players gain momentum again as soon as possible after completing a phase of play in order to reduce the probability of being injured in the next tackle in which they are involved. 9 dominating the tackle situation requires the tackler to close down the space between himself and the attacking player while ensuring a powerful leg drive into the tackle. shortening steps before contact, driving forcefully with the shoulder on the same side as the leading leg and hitting into the trunk is the safest and most effective way to execute a tackle. tackles from the front (front-on) have been shown to result in the greatest number of injuries and injury burden (days off) per 1 000 player-hours. 32 although this finding is largely due to the high frequency of the front-on tackle, a focus on this specific event has the greatest potential to reduce morbidity of tackle injuries. 8 furthermore, the nature of the game makes this tackle unavoidable and thus it is important to coach safe and effective techniques. previous research 41 reporting injury frequency to the tackler has shown injury to be greater when tackling the trunk (57%) than when tackling low (43%), but this may also be explained by the higher frequency of the trunk tackle (130 tackles per match) compared with the low tackle (30 tackles per match). a recent study 32 has found the injury rate and injury burden (days off) per 1 000 player-hours to be lower when performing a tackle to the middle zone (trunk) of the ball-carrier, compared with tackling low (legs). when assessing the tackling mode of all recorded ‘stopping’ front-on tackles, which was the tackling mode presenting the greatest number of injuries to the tackler, reported in the study by wilson et al., 41 64% of injuries occurred while tacking low (7 out of 11) and only 36% of injuries occurred while tackling the trunk (4 out of 11). an analysis of contact area playing styles has also observed that team success requires tackles to the waist, rather than leg tackles. 16 it may therefore safely be recommended that the zone between the upper thigh and the sternum be the target for contact when performing a front-on tackle; this recommendation will ensure safe and effective technique. sajsm vol 20 no. 3 2008 65 pg64-70.indd 65 10/22/08 10:48:12 am in a recent effort to further understand the relationship between tackle-related injuries and fatigue it was demonstrated that an effective tackling technique under non-fatigued conditions does not necessarily result in effective tackling technique when fatigued. 8 this emphasises the importance of conditioning, and provides evidence for advocating the practice of safe and effective tackling technique training under fatigued conditions. ball-carrying and taking the ball into contact although most frequencies are similar, the bulk of the published literature has shown the incidence of injury to the ball-carrier as being greater than to the tackler. 1,3,17,18,25,32,33 a recent comprehensive analysis of 52 248 tackle events in 10 050 player-hours has shown the burden (days off) of injury, which is a product of severity and rate of injury, to the ball-carrier to be nearly double the burden to the tackler. 32 thus, it may be argued that coaching safe and effective ball-carrying and attacking techniques is more important than coaching correct tackle techniques. anatomical sites most often injured by the ball-carrier include the lower limb (51%), the head, neck and face (17%), and the upper limb (15%). 41 the majority of injuries were sprains/strains (43%) and haematoma/bruises (29%). it has been reported that the injury with the highest incidence to the ball-carrier is a thigh haematoma for both forward and backline rugby players. 1 the injury resulting in most days absent in professional rugby players were anterior cruciate ligament and medial cruciate ligament injuries to the forwards and backs respectively. 1 non-fatal catastrophic cervical spine injuries have also been reported to occur to the ball-carrier, in similar frequencies to those of the tackler. 25,30 catastrophic cervical injuries to the ball-carrier are predominantly caused by illegal tackles. 25,30 both high tackles and spear tackles put the ball-carrier at a significant risk of cervical spine injury. spear tackling, which in rugby union is described as lifting the ballcarrier off his feet and driving him head first into the ground, has been outlawed and stricter enforcing of this law has recently been introduced. 15,25,30 the illegal high tackle is also outlawed due to its high risk. 15,25 tackles around the neck may force the neck into either hyperextension (bent backwards) or hyperflexion and rotation, which may be sufficient to cause fracture or dislocation of the cervical vertebrae and possibly severing of the spinal cord. cervical injury due to axial loading (as described in the section on tackling) may also occur in the ball-carrier either from being spear-tackled or making direct contact with the top of the head by entering the tackle with the head down. 25,30 the essential safe body posture of tackling also applies to safe technique when taking the ball into contact. when contact is unavoidable, the contact situation should always be entered with the head up and back straight. as explained in the section on tackling, loss of spinal lordosis has been shown to be a weaker position; greater force and torque may be transferred into the contact situation when a neutral back with natural lordosis is maintained. 10,21,26,27 effective and successful ball-carrying techniques have been well described. 22,35,37 dominating contact, 22,35 evading contact, 35 body position in contact 22,37 and turning towards your support 22,37 have all been shown to be associated with effective and successful ball-carrying. sayers and washington-king 35 characterised effective ball-carries into contact, and showed that maximal running intensity, running at an oblique angle and performing a forward step, all resulted in the greatest number of positive outcomes while carrying the ball. oblique evasive running (defined as running ‘towards the defensive line, but not directly at defenders; e.g. where an attacker ran at the shoulder of a defender’) measured much greater positive outcomes compared with running at a defender or angled running (defined as ‘runs not directed towards the defensive line; e.g. where an attacker tries to run around the defence using speed’). 35 performing a forward step (defined as an ‘evasive movement involving stepping motions originated from the outside leg and involving predominantly forwards motion’), displayed much greater positive outcomes than a lateral step (defined as an ‘evasive movement involving predominantly sideways stepping motion’) and a swerve (defined as an ‘evasive movement initiated from the inside leg). 35 dominating the tackle situation is essential to crossing the advantage line. when the ball-carrier was able to meet the tackler once he had crossed the advantage line, the ball was retained 67% of the time, compared with a ball retention rate of 44% when the advantage line was not reached. 22 as described for the tackler, the prevalence of injury is much greater to the player in the tackle situation with the lower momentum. 9 therefore, dominating the contact situation will once again emphasise the concept of safe technique also being the most effective technique. evasion techniques such as oblique running and forward stepping will reduce the magnitude of the collision forces, 35 thereby decreasing the effectiveness of the tackle while making the ball-carry safer and very effective. ball-carriers should not run directly at defenders – this will not only decrease the effectiveness of the ball-carry, 35 but also place the ball-carrier and the tackler under unnecessary risk of injury. a low body position by the ball-carrier and turning towards supporting players has also been shown to be associated with success in contact. 22,37 ball retention was the highest when the body position in contact was classified as low (56%), compared with a medium (47%) and a high (32%) body position, and when the ball-carrier turned his body towards his support (68%), compared with away from his support (62%) and not turning at all (42%). 22 a more recent analysis of the contact situation 37 showed similar results. it was found that possession was retained 90% of the time when the ball was carried into contact with a low body position. a low body position is not only the most effective carrying position, but also the strongest and safest. a low body position will widen the base of support, lower the centre of gravity of the ball-carrier and allow for a more powerful leg drive into contact. turning towards support in the tackle situation is a very significant action in retaining possession, 22,37 but also protects the ball-carrier from injury caused by more defenders joining the tackle situation. scrum setting and engagement when scrumming injuries are reported as the incidence of injury per player-hours, the high risk of the scrum situation is often underestimated, 6 but when evaluating the propensity of a contact event to induce injury, the scrum is the contact phase bearing the greatest injury risk. 6 scrumming was shown to carry a 60% greater risk of injury than the tackle situation. 6 it is furthermore worth noting that the vast 66 sajsm vol 20 no. 3 2008 pg64-70.indd 66 10/22/08 10:48:13 am sajsm vol 19 no. 4 2007 67 majority (>80%) of scrum injuries occur to the hooker and prop, 25,33 therefore emphasising safe and effective technique in these positions is particularly important. injuries to the head and neck contribute to 42% of all schoolboy scrum injuries. 33 scrumming has also been shown to be the phase of play which induces the greatest number of catastrophic cervical spine injuries. 30 although comparative data have never been published, the risk of catastrophic cervical injuries per event for the hookers and props (front-row forwards) during scrumming would be considerably greater than any other position during any contact event. 40 it has been shown that the impulsive impact force on a scrum engagement exceeds the threshold of injury to the spine. 23 this emphasises firstly the importance of specific scrum technique training, which includes correct alignment of the head, neck and trunk, and adequate back, shoulder and neck strength to maintain a safe body position during engagement. 23,36 more than 90% of scrum-related catastrophic cervical spine injuries occurred during either scrum engagement (47%) or a collapsed scrum (46%). 30 the remainder of injuries were caused by front-row forwards actively extending their necks and driving the opposite front-row upwards; this has been termed ‘popping’, 25 or more recently ‘scrumming up’. this act places the opposition at great danger of catastrophic cervical injury, is highly illegal and should be strongly discouraged. 15 during scrum engagement vertex impacts caused by head down contact (similar to what was described in the section on tackling) has the potential of causing catastrophic cervical injuries. 25,30 the crouch-touch-pause-engage sequence of scrum engagement was introduced to reduce the number of these injuries. 2,25 correct scrum setting and engagement techniques are extremely important, and if safe and effective techniques are sustained the scrum-related catastrophic cervical injury could be eliminated from the game. 18 the crouch signal from the referee should see the front row forwards assuming a stationary crouched position. although no research has related crouch position to force production in the scrum, a crouch position similar to the position of maximal force production while pushing is recommended. it is therefore recommended, for maximal force development as well as assurance of safety, that front-row players crouch with a low body position, a straight neutral spine (spine-in-line), face-up, and with their shoulders and hips at the same height. in the crouch position it is very important to emphasise a neutral cervical spine in natural lordosis. players are therefore recommended to have their chin up and off their chests, but not hyperextended (tilted backward). hyperextending in the crouch position will result in the need for flexion (bending the neck forward) in order to place the head under the opposite front-row. this act may place the front-row forward in a compromised position and increase the risk of catastrophic cervical injury. it is therefore recommended that players imagine they are looking at their opposite number in the crouch position over a pair on sunglasses placed on their nose. the engage signal from the referee should be followed by both sets of front-row players driving into one another, ensuring that they maintain spine-in-line for optimal force transfer and personal safety. research has shown that the magnitude of forward force generated by a pack of forwards once they have engaged is greater when the front row is packed as low as possible, 23 with the head, trunk and legs in alignment, and ensuring a maximal angle at the hip. 13 a practical evaluation of individual scrumming technique has shown that a horizontal spine is a strong predictor of scrumming performance. 4 the hip angle has been shown to be a factor when building a model for predicting maximal pushing force in the scrum; the mean hip angle in this study was 123 0 ± 24 0 . 28 the cervical, thoracic and lumbar spines are placed under a great amount of strain during the scrum engagement. evidence suggests that the cervical spine, thoracic and lumbar spines are able to bear the greatest amount of axial forces when the spine is in a neutral position with natural lordosis (spine-in-line). 10,21,26,27 the flexed and twisted spine was also less able to resist applied axial torques, thus a loss of the recommended spine-in-line may also increase the risk of torsional injury. 21 the collapsed scrum also presents great risk of vertex impacts and forced hyperflexion with or without rotation when the heads of the front-row forwards, especially the hooker, strikes the ground. 25,30 the most effective way of preventing scrum collapse is to ensure that there are no downward forces exerted on the engage. in a study of the kinetics of the scrum a downward force on all 3 front row players was recorded at all playing levels except for international frontrow forwards. 23,24 this indicates poor technique in non-international front-row forwards. maintenance of a flat straight neutral spine with natural lordosis (spine-in-line) will ensure maximal forward force transfer and no downward force generation. the lineout the propensity of the lineout to cause injury has recently been described as ‘very low’. 6 it has the lowest incidence of injury when recorded as injury per player-hours and per event. 1,6,17,18,25,33 interestingly, lineouts have the highest severity (days off per injury) of any contact phase, 6 and should therefore be an important consideration when assessing the risk factors for injuries. 29 cervical or lumbar spine facet joint injuries accounted for the majority of matchrelated contact injuries occurring during the lineout in professional rugby players. 6 although this study 6 reported that only 7% of all lineouts were penalised, a similar number of events resulting in medical on-pitch attention occurred in both penalised and non-penalised lineouts. the reported high frequency of cervical and lumbar facet injuries sustained in the lineout 6 was in all probability the cause of jumpers losing their balance and falling, from their lifted position when jumping, to the ground. preventing illegal actions (i.e. interfering with the opposite jumper or lifter to gain advantage) through stricter interpretation of the law and teaching the technique which offers the greatest stability to the jumping ‘pod’ (jumper and two supporters) may be effective ways of reducing lineout injuries. for optimal force generation players lifting the jumper should assume a low body position with straight spine. an effective lifting technique, from a performance perspective, is also the safest. to ensure maximal height the front supporter should grip the legs of the jumper just above the knees. stability from the front supporter may be increased by rotating the grip around the legs so that the two hands act as a clamp, keeping the legs of the lifter together while sajsm vol 20 no. 3 2008 67 pg64-70.indd 67 10/22/08 10:48:14 am also preventing lateral movement and imbalance of the jumper. the back supporter should keep his hands open and place the thumbs under the bulge of the buttocks (i.e. in the subgluteal fold) with the fingers folding around the back and outside of the thigh. both the grips described above will provide greater stability and a more efficient lifting position at full extension than the frequently used ‘shorts grip’. after the ball has been caught the back lifter should close the space and move around slightly to protect the jumper from the opposition and prevent him from being interfered with. supporters should be as close as possible to the jumper, as this ensures that the jumper reaches a maximal height, and also creates a stronger base of support. by decreasing the horizontal distance between the supporters and the jumper, supporters decrease the resistive torque exerted by the jumper, and will therefore experience less force on their bodies. 11 it is important that the jumper produces maximal power when initiating the jump. to ensure maximal power generation a counter-movement jump (i.e. bending the knees before the jump) should precede a maximal effort jump. once the jumper has captured the ball, the supporters should lower the lifter with controlled motion; dropping or letting go of the jumper might cause severe injury. the jumper should always maintain a straight body position, avoiding any flexion at the hip or knee joints, and should also ensure that a contracted core is maintained. although the specific lifting techniques mentioned above and their ability to create a safer and more effective lift have not been studied systematically, it may be argued that the techniques are supported by biomechanical principles. 34 the ruck and maul the tendencies of sustaining ruck and maul injuries have recently been classified as low and average, respectively. 6 the number of ruck and maul injuries sustained per 1 000 events was lower than the equivalent measure in the tackle and in the scrum. 6 haematoma injuries of the calf or shin caused the highest incidence and most days absent respectively for the forwards and backs during rucks, and medial collateral ligament injuries were the most common serious injuries associated with mauls. 1 a case review study has shown that the ruck and maul causes 17% of all catastrophic cervical spine injuries. 30 there are various possible mechanisms for catastrophic cervical injury. 25,30 firstly, the ruck and maul situation might lead to forced flexion of the neck, either to the ball-carrier or a player at the bottom of a ruck. secondly, head and neck injuries may result from vertex impacts caused by charging into a mass of players, either to the person charging and making head-first contact or to the person bearing the force of the contact. 25,30 thirdly, fracture and dislocation may occur from vertex impacts or forced hyperflexion and rotation similar to the mechanism described in the other contact phases of the game. 25,30 players joining the ruck, which is formed once ‘one or more players from each team, who are on their feet, in physical contact, close around the ball on the ground’, 15 should according to law 16, ‘have their head and shoulders no lower than the hips’. a strong effective technique with straight neutral spine in natural lordosis, face-up, shoulders above the hips and strong base of support will assist the necessary force production to clear opposition players off the ball and provide stability to stay on the feet, thus ensuring fast and effective ball availability for the scrumhalf. a straight neutral lumbar, thoracic and cervical spine is recommended due to the increased stability of the spine in this position. 11,21,26,27 the strongest position of the spine is essential in force production and injury prevention. although players should be coached not to charge into rucks head-first, the risk of vertex impacts around the ruck situation should always be reduced by keeping the face up; this avoids the risk of vertex impacts with a forward flexed cervical spine, which has been shown to be a very vulnerable position. 10,26 the above recommendations apply to defending players entering the ruck situation and attacking players securing the ball. players going off their feet or entering the ruck with their shoulders below the hips will not only be less effective at driving opposition players off the ball, but will also be penalised because this is also a transgression of the law of the game. the fundamental difference between the ruck and a maul is that ‘all players involved must be caught in or bound to the maul and must be on their feet’. 15 the above-mentioned principles of safe position in the ruck situation thus also apply to the maul. in the maul situation, the ball-carrier who remains on his feet is also at risk when he remains facing his opposition with his head down. 25 players should be encouraged to turn their back towards the opposition when held in a tackle as this action will enhance ball retention rate 22,37 and increase the safety factor when the maul is formed. this example once again demonstrates that safe rugby is effective rugby. acknowledgements the paper was commissioned by the boksmart programme, which is a national programme sponsored by absa and implemented on behalf of the south african rugby union and the chris burger/petro jackson player’s fund. the goal of the programme is to teach safe and effective techniques which will reduce the incidence and severity of injury, make the game safer for all involved and improve rugby performance. references 1. brooks jhm, kemp spt. recent trends in rugby union injuries. clin sports med 2008; 27: 51-73. 2. brooks jhm, fuller cw, kemp spt, reddin db. epidemiology of injuries in english professional rugby union: part 1 match injuries. br j sports med 2005; 39(10):757-66. 3. clark dr, roux c, noakes td. a prospective study of the incidence and nature of injuries to adult rugby players. s afr med j 1990; 77: 559-62. 4. coaches information website. assessment of scrumming performance. available at: http://cis.myile.com/index.php. accessed 26 may 2008. 5. fuller cw, molley mg, bagate c, et al. consensus statement of injury definitions and data collection procedures for studies of injuries in rugby union. br j sports med 2007; 41: 328-31. 6. fuller cw, brooks jhm, cancea rj, hall j, kemp spt. contact events in rugby union and their propensity to cause injury. br j sports med 2007; 41: 862-7. 7. fuller cw. managing the risk of injury. clin j sport med 2007; 17(3): 182-7. 8. gabbett tj. influence of fatigue on tackling technique in rugby league players. j strength cond res 2008; 22(2):625-32. 9. garraway wm, lee, aj, macleod da, telfer jw, deary ij, murray gd. factors influencing tackle injuries in rugby union football. br j sports med 1999; 33: 37-41. 10. gunning jl, callaghan jp, mcgill sm. spinal posture and prior loading history modulate compressive strength and type of failure in the spine: a biomechanical study using a porcupine cervical spine model. clin biomech 2001; 16(6): 471-80. 11. harman e. the biomechanics of resistance exercise. in: beachle tr, earle rw ii, eds. essentials of strength and conditioning. champaign, il: human kinetics, 2000: 25-55. 12. heck jf, clarke ks, peterson tr, torg js, weis mp. national athletics trainers’ association position statement: head-down contact and spearing in tackle football. j athletic training 2004; 39(1): 101-11. 68 sajsm vol 20 no. 3 2008 pg64-70.indd 68 10/22/08 10:48:14 am 13. hodge kp. spinal injuries in rugby scrums. res papers physical edu 1980; 2(4): 82. 14. international rugby board (irb). about irb organisation. available at: http://www.irb.com/aboutirb/organisation/index.html. accessed 2 june 2008. 15. international rugby board (irb). irb playing charter (irb rugby rules) 2008 edition. available at: http://www.irb.com/mm/document/lawsregs/0/completelaws_4809.pdf. accessed 2 june 2008. 16. jones nmp, mellalieu sd, james n, moise j. contact area playing styles of northern and southern hemisphere international rugby union teams. in: o’donoghue p, hughes p. performance analysis of sport vi. cardiff: uwic, 2005: 114-9. 17. kerr ha, curtis cm, micheli lj, et al. collegiate rugby union injury patterns in new england: a prospective cohort study. br j sports med 2008; 42(7): 595-603. 18. kew t, noakes td, kettles an, goedecke re, newton da, scher at. a retrospective study of spinal cord injuries in cape province rugby players, 1963 -1989. s afr med j 1991; 80:127-33. 19. macintosh as, mccrory p. preventing head and neck injuries. br j sports med 2005; 39: 314-8. 20. macintosh as, mccrory p, finch cf, wolfe r. head, face and neck injury in youth rugby: incidence and risk factors. br j sports med 2008. doi: 10.1136/bjsm.2007.041400. 21. mcgill sm. the influence of lordosis on axial trunk torque and trunk muscle myoelectric activity. spine 1992; 17(10): 1187-93. 22. mckenzie ad, holmyard dj, docherty d. quantitative analysis of rugby: factors associated with success in contact. j human movement studies 1989; 17: 101-13. 23. millburn pd. the kinetics of rugby union scrummaging. j sports sci 1980; 8: 47-60. 24. millburn pd. biomechanics of rugby union scrumming. sports med 1993; 16(3):168-79. 25. noakes td, du plesssis m. rugby without risk: a practical guide to the prevention and treatment of rugby injuries. pretoria: van schaik, 1996. 26. oktenoglu t, ozer af, ferrara la. effects of cervical spine posture and axial load bearing ability: a biomechanical study. j neurosurg 2001; 94(1 suppl.): 108-14. 27. patwardhan ag, havey rm, ghanayem aj, et al. load-carrying capacity of the human cervical spine in compression is increased under a follower load. spine 2000; 25(12): 1548-54. 28. quarrie kl, wilson bd. force production in the rugby union scrum. j sports sci 2000; 18: 237-46. 29. quarrie kl, alsop jc, waller ae, bird yn, marshall sw, chalmers dj. the new zealand rugby injury and performance project. vi. a prospective cohort study of risk factors for injury in rugby union football. br j sports med 2001; 35:157-66. 30. quarrie kl, cantu c, chalmers dj. rugby union injuries to the cervical spine and spinal cord. sports med 2002; 32(10): 633-53. 31. quarrie kl, gianotti s, hopkins wg, hume pa. effect of a nationwide injury prevention programme on serious spinal injuries in new zealand rugby union: ecological study. br med j 2008; 334(7604): 1150. 32. quarrie kl, hopkins wg. tackle injuries in professional rugby union. am j sports med 2008. doi: 10.1177/0363546508316768. 33. roux ce, goedecke r, visser gr, van zyl wa, noakes td. the epidemiology of schoolboy rugby injuries. s afr med j 1987; 71: 307-13. 34. sanders rh, wilson bd. some biomechanical tips for better teaching and coaching. n z j health phys edu recreation 1991; 23(3): 24(1&2). 35. sayers mgl, washington-king j. characteristics of effective ball carries in super 12 rugby. int j performance analysis sport 2005; 5(3): 92-106. 36. silver jr. the impact of the 21st century on rugby injuries. spinal cord 2002; 40: 552-9. 37. smyth g, o’donoghue pg, wallace es. notational analysis of contact situations in rugby union. in: hughes md, ed. notational analysis of sport iv. cardiff: uwic, 1998:156-64. 38. south african rugby union. community rugby department statistics. personal communication. 28 may 2008. 39. torg js, quedenfeld tc, moyer ra, truex r, speelman ad, nichols ce. severe and catastrophic neck injuries resulting from tackle football. j am coll health assoc 1977; 25: 224-6. 40. wetzler mj, akpata t, laughlin w, levy as. occurrence of the cervical spine injuries during the rugby scrum. am j sports med 1998; 26(2): 177-80. 41. wilson bd, quarrie kl, millburn pd, chalmers dj. the nature and circumstances of tackle injuries in rugby union. j sci med sport 1999; university of the western cape associate professor/professor in sport, recreation and exercise science the department of sport, recreation and exercise sciences at uwc has great potential to become a leader in promoting and developing communities through sport and other forms of physical activity. it is unique in that it offers a postgraduate qualification in sport and recreation management, as well as an opportunity for students to specialise in this discipline at the undergraduate level. in addition, it educates students in biokinetics and has well-established undergraduate and postgraduate programmes in the fields of sport, recreation and exercise science. the department has substantive international links with tertiary institutions offering opportunities for collaborative research and teaching. discussions with international colleagues to establish a sports research centre at uwc are underway. the department has a vacancy for an associate professor/professor with effect from 1 january 2009. the prime duty of any professor is to give advanced academic leadership. as in all academic appointments, the position entails administrative, research, research supervision, teaching and community outreach responsibilities. the successful candidate should possess the following: 1. a relevant doctoral degree; 2. a significant research track record in any of the exercise sciences; 3. high-quality, peer-reviewed publications; 4. a track record of successful postgraduate supervision; 5. experience in teaching at a tertiary institution in undergraduate and postgraduate programmes; and 6. an understanding of the demands and needs of relevant markets for which sport, recreation and exercise science students are being prepared. the successful candidate must be willing to facilitate the establishment of a sports research centre and to work in interdisciplinary teams. in addition, the candidate would be expected to stimulate and co-ordinate research, attract project funding, and develop strategic research plans. your application should highlight your strengths as an educator and researcher in the exercise science area and should be accompanied by a full curriculum vitae and the names and full contact particulars, i.e. e-mail addresses, telephone and cell numbers and postal addresses of three referees. further information may be obtained from dr s bassett on telephone (021 9592350) or e-mail: sbassett@uwc.ac.za. the closing date is 24 october 2009. applications should be addressed to: ms g alexander e-mail: galexander@uwc.ac.za, or at human resources department, university of the western cape, private bag x17, bellville 7535, south africa. tel: +27-21-9593626. fax: +27-21-959-1447. in line with the university’s commitment to diversifying its workforce, applications from the designated groups will be given priority consideration. the university reserves the right not to make an appointment or to make an appointment at a lower level. we will only correspond with short-listed candidates. pg64-70.indd 70 10/22/08 10:48:15 am 106 sajsm vol. 24 no. 4 2012 editorial a few weeks ago an italian court convicted seven weather scientists for manslaughter.1 their crime? they failed to adequately warn residents before a tremor struck central italy in 2009. more than 300 people were killed as a result of the quake. the scientists were sentenced to 6 years’ i mp r i s o n m e nt f o r g i v i n g ‘ i n e x a c t , i n c o mp l e t e a n d contradictor y information’ about whether small tremors felt in the weeks and months before the earthquake constituted grounds for a more serious warning about an impending earthquake. although the scientists claimed that the science of tremors was not sufficiently reliable to predict earthquakes, the judge did not share this view. this got me thinking about the disciplines of sports medicine, physical activity, health and sporting performance, and i wondered if there would ever be a case when practitioners in these disciplines were held accountable for any event that they failed to predict accurately. my personal interest lies in chronic fatigue, specifically being able to anticipate or predict the onset of chronic fatigue before the symptoms become serious, affecting health and performance. i have sometimes described my role akin to that of a weather forecaster who gathers information about prevailing conditions and then makes a decision about what is going to happen in the future. does that put me in the same category as these italian scientists if i get it wrong? this is a relatively innocuous example; lives are unlikely to be lost if the prediction is incorrect. however, there are many far more serious examples that may have life-threatening consequences for an athlete. for example, it is well known that repetitive head injuries have longterm consequences that manifest years after the athlete stops playing sport. how soon will it be before an athlete who has experienced repetitive head injuries as a result of playing sport forms a strong case, and charges those administrators or service providers to whom he had given his trust during the competitive years? what about an athlete who has developed arthritis in a joint as a result of an injury during a competition and then rehabilitated with an accelerated programme so that he/she could get back into competition? with our current information, does the athlete not have a case against the practitioners involved in the rehabilitation? the scenarios extend beyond high-level sport. what about the general practitioner’s diabetic patient who lodges a complaint that the gp did not give adequate advice about the importance of nutrition and regular physical activity in managing the condition? the list goes on and on. some other examples are considered and unpacked in the paper ‘lifetime injury prevention: the sport profile model’, which is published in this edition.2 this article was published in the british journal of sports medicine (bjsm) and rated as an editor's choice paper. bjsm have given us permission to re-publish editor’s choice papers in the south african journal of sports medicine. the paper shows that participating in sporting activities carries a risk of injury ranging from trivial to large. some of these risks are known and quantifiable at the onset, others are not. as more information about physical activity and health becomes available, so the responsibility of the practitioners who are administering and prescribing the treatments increases. part of this responsibility is to communicate the risk of injury to the patient or athlete. the participant needs to be sensitised to all these risks so that an informed decision can be made about whether participation in the sport is justified. we are going through a phase of seeing harsh measures being taken against athletes who have been caught doping, including forcing the athlete to return the prize money won while they were using drugs to enhance performance. with the high-profile case of lance armstrong, a precedent has been set. the bar has been raised for achieving fairness in sport and it is likely to become the norm. the same argument can be made for service providers who are tasked with looking after the well-being and health of athletes. the bar has also been raised for them. how soon will a service provider be asked to return money for below-par services rendered to an athlete, or for services that did not consider or take advantage of the most current information? unfortunately all these points suggest that we are likely to see an increasing number of litigation cases seeking compensation for longterm health problems arising from sports injuries. let's just hope that the legal authorities do not take such a drastic stance as the italian authorities took against the weather scientists. mike lambert editor-in-chief 1. camilli a. 7 jailed for failing to predict quake. http://www.iol.co.za/news/world/7jailed-for-failing-to-predict-quake-1.1408815#.uj1ctqxz7s(accessed 23 october 2012). 2. webborn n. lifetime injury prevention: the sport profile model. br j sports med 2012;46(3):193-197. [http://dx.doi.org/10.1136/bjsports-2011-090417] s afr j sm 2012;24(4):106. doi:10.7196/sajsm.363 italian weather scientists and sports scientists – is there a link? http://www.iol.co.za/news/world/7-jailed-for-failing-to-predict-quake-1.1408815#.uj1ctqxz7shttp://www.iol.co.za/news/world/7-jailed-for-failing-to-predict-quake-1.1408815#.uj1ctqxz7shttp://dx.doi.org/10.1136/bjsports-2011-090417] this is the last edition of the south african journal of sports medicine for 2007. four editions of the journal have been published in 2007, with 21 articles (original research, opinions and letters). over 50% of these articles are unique to the south african context. it is becoming more difficult to publish good-quality research with a local interest in international journals so therefore it is logical that the ‘local’ journals assume the responsibility of publishing this work. the goal of the south african journal of sports medicine is to encourage and increase this proportion of published articles while still maintaining a high standard. sometimes researchers feel that high-quality research of a local interest is ‘wasted’ in a local journal because they do not get the credit for the paper that they would get from an international journal. we are cognizant of this and are in the process of getting the south african journal of sports medicine isi rated. this international rating is a difficult and lengthy process and involves a peer review of the journal over several years. we are confident we have met all the requirements and wait with keen anticipation for the outcome of the review which is currently underway. we should have feedback by the middle of 2008. once the journal is isi rated all published papers will be incorporated into the pubmed database and will therefore get much more international exposure. the journal is currently on the government-accredited list of journals and this status will not be negatively affected if the journal gets isi accreditation. while we glow in the success of the springboks at the rugby world cup it is appropriate to reflect on the contribution that the sports medicine support staff made to the victorious team. after reading jake white’s book (in black and white) it is clear that the coach valued the input of his medical support team and acknowledged the role they had in the success of the team. the management of the health and fitness of professional rugby players in south africa is world class, and rugby is the only sport which consistently implements a multidisciplinary approach in managing the players. a challenge for all of us is to utilise this vast database of experience and intellect, and transfer it to the other sports which are currently lagging behind. fingers are crossed that we are not going to be exposed in the 2008 olympics in beijing. the support structures for rugby worked together for 4 years – at the time of writing the medical support team for the olympics 6 months away has not yet been announced. on another note, the journal is going to have to be stricter about publishing papers which do not have appropriate ethical clearance – this includes informed consent from subjects. this is a trend being adopted in journals all over the world. there is also some talk about the department of health playing a bigger role in granting permission for research to be done on children, particularly at schools. while it may be argued that this will tighten up the standard of research and reduce the risk of poor-quality studies, there is also concern that this will be another bureaucratic hurdle which researchers are required to clear. anyone dealing with the medicines control council from a research perspective will know that the bureaucracy is unwieldy – another body imposing the same level of bureaucracy will stifle many aspiring projects. surely the various ethics committees around the country can fulfil the role of quality control? news the south african sports medicine association (sasma) and the south african institute for drug free sport have announced a partnership to combat doping in sport. the past president of sasma, dr demitri constantinou, said that ‘sasma is pledging its members to respect the rule of law in the fight against doping and to practise ethically in that respect; and further, in the optimal care of athletes and sports participants at all levels, using best practice knowledge and models. athletes sanctioned for doping offences may have been incorrectly advised and guided by some health care practitioners, sometimes even deliberately, and these professionals should be held accountable’. dr louis holzthausen is the new president of sasma. the staff of the journal wishes him all the very best for his term of office. the past president, dr demitri constantinou, is congratulated and thanked for the tireless effort he has put into sama during his term of office. mike lambert editor-in-chief rugby setting the pace a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial sajsm vol 19 no. 5 2007 105 pg105.indd 105 1/11/08 11:11:48 am original research 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license the impact of a fast bowling spell on physiological, perceptual and performance responses in non-elite cricketers l pote, phd; s proctor, bsc (hons) human kinetics and ergonomics; k mcewan, bsc (hons) human kinetics and ergonomics; j p davy, phd; c j christie, phd department of human kinetics and ergonomics, rhodes university, grahamstown, south africa corresponding author: l pote (l.pote86@gmail.com) fast bowlers are essential to a cricket team’s success as they assist in restricting the number of runs scored by the opposing team.[1] this is achieved through manipulating factors such as the line, length, lateral deviation and speed of ball delivery.[1,2] the line and length are highly dependent on the batter facing the ball, external weather conditions, as well as the surface of the pitch.[2] fast bowlers strive primarily to attain high ball speeds (together with accuracy) as this reduces the time available to the batsmen to process the delivery and execute an appropriate motor response.[1,2] the attainment of high ball speeds requires fast bowlers to perform multiple actions simultaneously, in a short period of time (approximately one second), placing immense physical demand on the body.[1] this may negatively affect performance-related parameters, such as ball release speed and accuracy.[2,3] furthermore, these actions are performed repeatedly and at high intensities, during training and competition.[4,5] as a result, fast bowlers have the highest risk of injury, with prevalence rates of approximately 42%.[4] despite indirect evidence of the physical demands of fast bowling, very few studies have focussed on identifying and describing these variables.[3,5] a reason for this may be linked to the fact that it is difficult to quantify the loads being placed on the bowler and the resultant responses, because of the irregular ‘stop-start’ nature of fast bowling.[5] furthermore, care should be taken when interpreting the current available literature/research as it focuses primarily on the acute responses to bowling load, such as heart rate, blood lactate concentrations and hydration status.[6] only a paucity of evidence exists which describes/compares the relationship between the physiological, biomechanical and perceptual demands of fast bowling and performance in a competitive environment.[3,8] this is despite these factors being found to comprise the cornerstones of the conceptual model (centre-m model) for studying human movement.[5] additionally, no study has examined the impact of lower limb fatigue on bowlers despite the fact that in other intermittent sports functional strength was used to investigate this response.[7] nevertheless, there is a need to obtain data from different calibres of players to corroborate the validity of such findings. further research that is based on a holistic, interdisciplinary approach is required to deepen the understanding of the physical demands of fast bowling, so that injuries may be prevented and performance improved.[5] therefore the purpose of this study was to investigate the effects of a fast bowling protocol on the physical, perceptual and performance responses in non-elite fast bowlers. methods study design and participants this investigation was a repeated measures design that assessed the impact of a fast bowling protocol on selected physiological, perceptual and performance measures over time. eight male, non-elite firstand second-team schooland university-level fast bowlers, between the ages of 17 and 21 years, were recruited (age and level of experience were controlled). fast bowlers were defined as those players bowling over 80 km.h-1 with a run-up of between 15 and 30 m. the study was approved by the rhodes university ethical standards committee (rhodes university, grahamstown, south africa) (ru-hsd-15-06-0012) and players were informed of the risks and benefits of the investigation. testing procedure the testing occurred in two phases, initially including background: the demands placed on fast bowlers may elicit unique responses that contribute towards increased injury risk and comprised performance capabilities. despite this, very few investigations have attempted to quantify these demands and their impact on performance in cricketers. objective: this investigation attempted to quantify the effects of a fast bowling protocol on the musculoskeletal, physiological and perceptual responses of fast bowlers; as well as ball speed and accuracy. methods: eight young adult bowlers (20 ± 2 years) participated in a 10-over bowling protocol that had been separated by intermittent fielding drills into three bowling spells respectively (4-, 3and 3overs). selected responses were collected throughout the protocol. results: functional strength was measured and showed no change. heart rate responses increased significantly (p<0.05) at the start of the bowling protocol. local ratings of perceived exertion increased significantly (p<0.05) as a function of exercise duration, while low to moderate intensities of perceived discomfort were noted in the anterior and posterior shoulder areas, upper portion of the lower limb musculature, as well as in the middle and lower back regions. performance responses experienced no significant change. conclusion: there was no significant change in ball release speed and accuracy across the bowling protocol. lower limb muscle power remained consistent and heart rates reached a steady state after the first over. in comparison, local ratings of perceived effort and body discomfort increased over time, which could mean that those unchanged measures do not accurately reflect fatigue or that perceptions are a more effective indicator of impending fatigue. keywords: accuracy, speed, heart rate, body discomfort, ratings of perceived exertion s afr j sports med 2019;31:1-5. doi: 10.17159/2078-516x/2019/v31i1a5624 mailto:l.pote86@gmail.com http://dx.doi.org/10.17159/2078-516x/2019/v31i1a5624 https://orcid.org/0000-0003-1371-2616 https://orcid.org/0000-0003-0727-0014 https://orcid.org/0000-0002-7529-5590 original research sajsm vol. 31 no. 1 2019 2 accustoming the cricketers to the testing procedures, as well as the collection of selected baseline, demographic and anthropometric measures. secondly, cricketers were required to simulate a bowling protocol following a dynamic warm-up focusing specifically on the upper and lower limbs of the body, in addition to the lumbar area of the spine. the bowling protocol was based on a time-motion analysis that determined the time between deliveries, as well as the time taken to switch ends at the completion of the over.[8] previous research has shown that the average time between deliveries was 39 seconds and the change of ends after each over took approximately one minute and 20 seconds, which were the intervals used in this study.[8] these intervals are similar to those of competitive schoolboy matches determined anecdotally and by the authors’ personal experiences. the change over period was simulated by the player walking around slowly to a specified point on the cricket pitch. after the completion of each changeover, intermittent fielding drills were completed which lasted for three minutes 54 seconds each, while the other bowler did his bowling spell. fielding drills involved walking ten metres towards the stumps as each ball was delivered by the other bowler.[3] each player was also expected to run for 20 metres on the second and fourth ball of the over and to field a total of one ball that was randomly completed during the over.[3] following this, the one minute 20 seconds changeover was once again initiated to allow the players to get ready to begin the next over. since the maximum number of overs that can be bowled during a 50-over match has been identified as ten which was selected as the number of overs to be bowled for this particular bowling protocol. the specified number of overs to be bowled was further divided into three bowling spells (4-, 3and 3overs respectively) since it is very rare for all ten overs to be completed in succession. once the protocol was complete, each player cooled down with stretches. the stretching session involved static stretches of both lower and upper limbs, as well as any other stretches that the participants felt they needed. measurement and instrumentation physiological measures heart rate was measured throughout the protocol using a polartm f11 heart rate monitor (polar electro oy, kemple, finland) in beats per minute (beats.min-1). the monitor was placed around the participant’s chest with an elastic strap and aligned with the sternum at the level of the inferior border of the pectoralis muscles. functional strength (lower limb power) was measured preand posttraining, using the countermovement jump. players had to stand upright with their feet between 12.5 – 25.0 cm apart. on their dominant side, a white a1 sheet had been positioned on a wall next to them. while in this standing position, each participant was then asked to place black paint on their middle finger and stretching their arm up as high as they could, to touch the white sheet at their highest point their standing reach height. they then had to move into a squat position and jump up as high as they could in one explosive movement. while airborne, they had to touch the white a1 sheet again at their highest point using their blackened middle finger. countermovement jump measures were used to calculate muscle power based on a prediction formula (equation 1) known as the sayers equation:[9] peak power (watts) = 60.7 x (jump height [cm]) + 45.3 x (body mass [kg]) – 2055 (eq. 1) where jump height = height of jump – standing reach height perceptual measures perceived exertion was assessed using a rating of perceived exertion scale developed by borg.[10] the scale ranges from a value of six, which represents perceptions of minimal exertion, to a value of 20, which represents maximal exertion. players were required to focus on ‘local’ rating of perceived exertion, as this provided an indication of perceived effort in the lower limb musculature, which included a single score specific to the quadriceps and hamstrings. to assess perception of body discomfort, at the end of each over the body discomfort scale and map developed by corlett and bishop was utilised.[11] once the areas experiencing discomfort had been demarcated, a likert scale on a scale from one to ten was used to rank the intensity of their discomfort. a value of one signified no discomfort and a value of ten represented extreme discomfort. performance measures ball release speed was measured using a sports radar gun (sr 3600, sports radar ltd, florida, usa) placed directly behind the stumps at the non-strikers end. accuracy was assessed using an accuracy board originally developed by portus et al., which has three scoring zones (100, 50 and 25).[12] the maximum scoring zone (100 points) rewarded balls that passed in line with the middle stump to approximately 25 cm outside off stump. the two other zones (50 and 25 points respectively) rewarded deliveries based on their impact point on the target, with 25 points being awarded to deliveries landing furthest away from the stumps within the target area. for deliveries that did not hit the target, a score of zero was awarded. statistical analysis exploratory data analysis was conducted to examine data distributions, check for normality and identify outliers. pre and post-protocol data were compared using the nonparametric wilcoxon signed-rank test. changes in physiological, perceptual and performance measures over time were analysed using kruskal wallis tests, followed by post hoc mann-whitney u test with bonferroni corrections. all data were analysed using statistica™ version 7 software (statsoft, south africa, 2016). significance was set at p < 0.05. results demographic, anthropometric and morphological parameters a total of eight fast bowlers, with a mean age of 20 (± 2) years, height of 185.6 (± 7.7) cm, body mass of 78.6 (±13.9) kg, body mass index of 22.8 (±3.3) kg/m2 and a body fat percentage of 8.8 (±2.9) % participated in the study. players participated in, on original research 3 sajsm vol. 31 no. 1 2019 average, 3.6 days of moderate to high-intensity exercise per week. physiological responses lower limb peak power was unchanged, preand post, in each bowling spell and there was no difference between spells (fig. 1). heart rate was significantly (p<0.05) elevated during all overs compared to the reference heart rate measured at the start of the protocol (fig. 2). overall, the heart rate remained constant throughout the bowling protocol. the lowest heart rate was observed following the first over (160 ± 14 beats.min-1). the highest was recorded following the fifth (167 ± 22 beats.min-1) and tenth (167 ± 11 beats.min-1) overs. a large interindividual variability was evident following the fifth over (± 22 beats.min-1). performance responses there was no change in either ball release speed or accuracy (fig. 3). the lowest mean ball release speed was during the third over (90.81 ± 5.09 km.h-1) and the highest was during the tenth over (95.0 ± 7.6 km.h-1). the lowest mean accuracy score was in the third over (305.6 ± 80.8). the highest was in the ninth over (403.1 ± 94.0). a large interfig. 1. mean (±sd) countermovement jump measures, preand post-spells. fig. 2. mean (±sd) change in heart rate (beats.min-1) between each over bowled. a* indicates significant difference (p<0.05) between reference heart rate and all other heart rate measures. fig. 3. mean (±sd) change in ball release speed (km.h-1) and accuracy score between each over bowled. original research sajsm vol. 31 no. 1 2019 4 individual variability was apparent during overs six (± 124.7) and seven (± 177.7). perceptual responses body discomfort was most commonly experienced in the anterior and posterior shoulder areas of the bowling arm, the upper portion of the lower limb musculature, and the middle and lower back regions. discomfort was also reported primarily on the posterior aspect of the body, particularly on the bowling arm side, lower back region and the lower limb musculature (fig. 4). frequency and relative intensity of discomfort in the shoulder regions remained largely unchanged throughout the three bowling spells. with regard to the back region, discomfort was observed in both the lower and middle back regions, with intensity increasing only marginally with each bowling spell. contrastingly, a high number of players reported discomfort in their hamstrings, particularly of the non-leading leg. this discomfort increased in intensity throughout the three bowling spells. the frequency of reports for discomfort in the feet was greatest on the anterior side during the third spell, with moderate intensities being reported, particularly on the side of the leading leg. significant increases (p<0.05) in ‘local’ exertion ratings were evident between overs one and four to ten (fig. 5). the lowest ‘local’ exertion rating was experienced at the end of the first over (10 ± 2) and the highest was at the end of the tenth over (14 ± 2). discussion the most important finding from this study was that performance was unchanged over the course of the bowling spell. this is the first study to show unchanged performance measures in an adolescent cohort. studies done on nonadolescent bowlers have also shown unchanged performance with similar ball release speeds over time.[3,12] this could be due to the fact that simulated protocols do not accurately reflect the demands experienced during real match situations.[3] the only study which found a change in performance was a 12-over simulated protocol[13] . however, this is extreme and not appropriate for adolescent players nor is it typical within a cricket game generally.[13] while perceptions of effort and discomfort may pre-empt fatigue and injury risk, it is important to acknowledge the role of skill and mental aptitude, specifically the ability to concentrate on performance for a prolonged period of time.[14] this can also impact performance measures as shown in previous studies.[14] although in other fig. 4. mean (±sd) anterior and posterior perceptual ratings of body discomfort and frequency of rating for spell 1, spell 2 and spell 3. fig. 5. mean (±sd) change in ‘local’ ratings of perceived exertion of the lower limb musculature (quadriceps and hamstrings) between each over bowled. *b indicates significant increases (p<0.05) in ‘local’ exertion ratings between overs one and four to ten. original research 5 sajsm vol. 31 no. 1 2019 studies, accuracy was also unchanged, different accuracy measures have been used in different studies thus making comparisons difficult.[3,12] furthermore, lower limb power was unchanged which supports previous findings.[3,13] changes in strength are usually attributed to muscular fatigue which was not found in this study as a result of this protocol.[2,5] by contrast, this study highlighted the local perception of strain experienced by bowlers, specifically in the hamstrings. this is an important finding as bowlers may perceive effort prior to changes in muscle power and/or strength which could possibly predispose them to injury even when other markers of fatigue remain intact (i.e. performance, lower limb power and heart rate). this finding needs to be investigated further as it could be a good indicator of the occurrence of potential injury. heart rate reached steady state after a significant increase from the first over, indicating that exercise intensity remained similar for the remainder of the protocol. this is a finding which has been reported previously.[3,13] conclusion in conclusion, this study found that performance was consistent across a 10-over bowling spell and that lower limb muscle power remained unchanged. heart rates reached steady state after the first over. by contrast, local ratings of perceived effort and body discomfort increased over time. this could mean that those unchanged measures do not accurately reflect fatigue or that perceptions are better indicators of imminent fatigue and potential injury risk. these authors had found previously that fast bowlers are the players most at risk of injury in cricket[15]. conflict of interest and source of funding: none author contributions: l pote: conceptualisation. design of methodology. writing. s proctor: conceptualisation. design of methodology. data collection. analysis. k mcewan: analysis. writing. j p davy: student supervision. c j christie: conceptualisation. design of methodology. results validation. writing. student supervision. project leadership and management. references 1. stuelcken m, pyne d, sinclair p. anthropometric characteristics of elite cricket fast bowlers. j sports sci 2007;25(14):1587–1597. [doi:10.1080/02640410701275185] 2. woolmer b, , noakes t, moffett h. bob woolmer’s art and science of cricket. london: new holland publishers ltd, 2008, page 526-530. 3. duffield r, carney m, karppinen s. physiological responses and bowling performance during repeated spells of mediumfast bowling. j sports sci 2009;27(1):27–35. [doi:10.1080/02640410802298243] 4. davies r, du randt r, venter d, et al. cricket: nature and incidence of fast-bowling injuries at an elite, junior level and associated risk factors. s afr j sports med 2008;20(4):115–118. [doi: 10.17159/2078-516x/2008/v20i4a275] 5. christie, cj-a. the physical demands of batting and fast bowling in cricket. in: zaslav kr, ed. an international perspective on topics in sports medicine and sports injury. london: intechopen ltd, 2012:321–332. [doi:10.5772/27301] 6. mcnamara dj, gabbett tj, naughton g, et al. training and competition workloads and fatigue responses of elite junior cricket players. int j sports physiol perform 2013;8(5):517–526. [doi:10.1123/ijspp8.5.517] 7. nuzzo jl, mcbride jm, cormie p, et al.. relationship between countermovement jump performance and multijoint isometric and dynamic tests of strength. j strength cond res 2008;22(3):699-707. [doi: 10.1519/jsc.0b013e31816d5eda] 8. christie cj-a, sheppard b, goble d, et al. strength and sprint time changes in response to repeated shuttles between the wickets during batting in cricket. j strength cond res 2018 vol.pub ahead of print. [doi: 10.1519/jsc.0000000000002585] 9. sayers sp, harackiewicz dv, harman ea, et al. crossvalidation of three jump power equations. med sci sports exerc 1999;31(4):572-577. [pmid:10211854] 10. borg ga. psychophysical bases of perceived exertion. med sci sports exerc 1982;14(5):377–381. [doi:10.1249/00005768198205000-00012] 11. corlett en, bishop rp. a technique for assessing postural discomfort. ergonomics 1976;19(2):175-182. [doi: 10.1080/00140137608931530] 12. portus mr., sinclair pj, burke st, et al. cricket fast bowling performance and technique and the influence of selected physical factors during an 8-over spell. j sports sci 2000;18(12):999–1011. [doi:10.1080/026404100446801] 13. taliep ms, gray j, st clair gibson a, et al. the effects of a 12over bowling spell on bowling accuracy and pace in cricket fast bowlers. j hum mov stud 2003;45(3):197-217. 14. goble d, christe cj. cognitive, physical and physiological responses of school boy cricketers to a 30-over batting simulation. j sports sci 2016;35(12):1148-1154. [doi:10.1080/02640414.2016.1211731]] 15. pote l, christie cj. injury prevention strategies in cricket. strength cond j 2018; 40(5):34-43. [doi: 10.1519/ssc.0000000000000409] editorial 1 sajsm vol. 30 no. 1 2018 the transition of the south african journal of sports medicine the first editorial last year explained that the south african journal of sports medicine was moving to a format where papers are published online immediately after being accepted, rather than waiting for a complete volume before the papers are published. a year later we can confirm the transition has been successful. the time from acceptance to publication has been reduced to under 3 weeks. we are still working on reducing the time it takes to review a paper, but this is an ongoing challenge that all journals are facing. demands on reviewers are increasing, so we are prepared to accept that reviewers may take longer to review a paper than we would prefer; however, this is a compromise we are prepared to make if it results in good quality reviews. it is well known that the quality of any journal depends on the quality of reviewers. a growing list of electronic databases index papers published in the south african journal of sports medicine. currently the list of databases includes; ajol, crossref, dhet, doaj, open archives registry, pkp index, sabinet, scielo sa, sherpa/romeo, university of illinois oai-pmh data provider registry, web of knowledge (wok) (links can be found on the journal website). another positive outcome of the new format of the journal is that published papers are freely available and permanently accessible online, without subscription charges or registration barriers. authors are allowed to post the entire paper on a personal website, providing the original source is referenced and the doi included as part of the citation. we are also adjusting the editorial board to ensure we maintain an internationally competitive standard and also reflect the diversity of research we publish in the journal. the editorial board is a key factor in the status of a journal. editorial board members are expected to have an advisory role and promote the journal wherever possible. they are also expected to source new submissions and occasionally review or assist in recruiting reviewers for submitted manuscripts. it gives me pleasure to announce that dr vincent gouttebarge has joined our editorial board. he is based at the academic center for evidence based sports medicine (aces), academic medical center, amsterdam, netherlands and is the chief medical officer of the international federation of professional footballers (fifpro). it goes without saying that his profile and experience will be an asset to the journal. we are also trying to adapt to the international trends in sports medicine and exercise science. for example, topics on concussion, screening for injury, and translating research into practice are topics of international interest and relevance. papers on these topics are in various stages of review in our journal. we are also particularly interested in research topics with a local interest and will be encouraging more of this research. the case study section will also be active and provides an opportunity for practitioners to be actively involved in research. the stimulus for innovative research ideas often begins at the level of the case study. i would like to end by referring readers to a wonderful paper i have just read entitled “living like an academic athlete: how to improve clinical and academic productivity as a gastroenterologist” [1]. i was drawn to the paper after listening to the podcast in which the two authors, both academic physicians were interviewed (www.asianefficiency.com/podcast/). on the podcast the two authors of the paper, drs eric benchimol and richard keijzer discuss strategies they have adopted to make themselves more successful in achieving their academic/clinical goals. they explain that academic clinicians have to manage their time to be able to look after patients, do research and teach while maintaining the mounting administrative load. a failure to manage time effectively results in a sub-optimal performance with increasing levels of stress. the authors used the term “academic athlete” to define a state which makes one happier, more fulfilled and more productive. this concept was influenced by an article on becoming a “corporate athlete”. [2] this paper suggested that corporate executives performing at high levels over the long periods would have to train/work in the same systematic, multilevel way as high-level athletes. benchimol and keijzer have transferred the concepts in this paper and applied them to the challenging job of being an academic clinician. they start by using the acronym s.m.a.r.t. to define goals (specific, measurable, agreed upon (with mentor/supervisor), realistic and time-based). they offer a list of resources one can use to improve productivity. they discuss the importance of routines, avoiding distractions and blocking time for high level work. importantly they make the point of self-care which involves adequate sleep, exercise, mindfulness and nutrition. there are many gems embedded in the article and anyone striving to improve their academic/clinical performance is advised to read this. mike lambert editor-in-chief s afr j sports med 2018;30:1. doi: 10.17159/2078-516x/2018/v30i1a4796 references 1. benchimol, e. i., & keijzer, r. (2018). living like an academic athlete: how to improve clinical and academic productivity as a gastroenterologist. gastroenterology, 154(1), 8–14. http://doi.org/10.1053/j.gastro.2017.11.017 2. loehr, j., & schwartz, t. (2001). the making of a corporate athlete. harvard business review, 79(1), 120–8– 176. http://www.ajol.info/index.php/sasma http://www.crossref.org/06members/51depositor.html https://doaj.org/toc/2078-516x http://www.openarchives.org/ http://www.openarchives.org/ http://index.pkp.sfu.ca/index.php/about http://reference.sabinet.co.za/sa_epublication/m_sajsm http://www.sherpa.ac.uk/romeo/search.php http://gita.grainger.uiuc.edu/registry/ http://gita.grainger.uiuc.edu/registry/ http://academyofsciencesa.wikispaces.com/file/view/media+release.pdf http://www.asianefficiency.com/podcast/ http://dx.doi.org/10.17159/2078-516x/2018/v30i1a4796 http://doi.org/10.1053/j.gastro.2017.11.017 original research 28 sajsm vol. 27 no. 2 2015 background. studies investigating the relationship between exercise and haemodynamic regulation conducted in older caucasian and black african populations suggest that lifestyle modification is effective in the management of numerous disease processes. there are few longterm studies in young healthy populations and even less is known about the influence of habitual exercise on autonomic and haemodynamic variables in young black african subjects. objective. to investigate the benefit of prolonged exercise on cardiovascular and haemodynamic variables in young healthy black african males. methods. fifty-five healthy male volunteers between 18 and 22 years of age participated in this prospective 20-week mediumto highintensity exercise intervention study with a self-control design. the finometer pro (finapres medical systems, the netherlands) was used for non-invasive data sampling of a number of cardiovascular and autonomic variables. results were generated by computer algorithm and were analysed using non-parametric wilcoxon signed rank tests. results. significant (p<0.05) cardiovascular changes included an increase in aerobic capacity, stroke volume, cardiac output and ejection fraction, and a decrease in diastolic blood pressure and heart rate. there was a significant decrease in total peripheral resistance and ascending aorta impedance. systolic blood pressure, mean arterial pressure and arterial compliance remained unchanged, while the decrease in blood pressure variability was not statistically significant (p>0.05). conclusion. the measured changes suggest a favourable response to exercise and imply that habitual exercise may be an important lifestyle modification for reducing the risk of cardiovascular disease in young black african males. s afr j sports med 2015;27(2):28-32. doi:10.7196/sajsm.564 cardiovascular and autonomic response induced by a 20-week military training programme in young healthy south african males p c zondi,1 mb chb, msc (sports med), mba; d c janse van rensburg,1 md; c c grant,1 phd (physiology); l fletcher,2 phd (statistics) 1 section sports medicine, department of orthopaedics, faculty of health sciences, university of pretoria, south africa 2 department of statistics, university of pretoria, south africa corresponding author: p c zondi (phatho.cele@up.ac.za) epidemiological studies show that, compared with their caucasian peers, individuals of black african descent have a higher prevalence of cardiac risk factors.[1,2] black africans have stiffer large central arteries, impaired dilation of small peripheral arteries and a greater prevalence of hypertension, diabetes and cardiovascular disease.[2-4] it is well established that a number of cardiovascular indices, such as arterial stiffness, blood pressure and autonomic regulation, are differentially affected by ageing.[5] the influence of western lifestyle (sedentary behaviour and increased consumption of high-energy processed foods) and rural urbanisation in sub-saharan africa has seen a shift in the underlying population distribution of risk factors for cardiovascular disease.[6] younger populations are increasingly affected by metabolic and cardiovascular illness; in america, the percentage of youths with chronic disease has almost quadrupled in the past 45 years, with racial minority children being disproportionately affected.[7] research shows that an increase in childhood chronic diseases results in an increase in adulthood illnesses,[7] and as such, methods need to be sought to curb this increasing epidemic. chronic inactivity is associated with increased cardiovascular risk and is a key factor in the progression of chronic disease.[5,8] conversely, regular physical activity has been shown to result in structural and functional vascular adaptations that protect against cardiovascular and metabolic disease.[5,8] the majority of studies examining the effect of exercise on cardiac and vascular function have been conducted on caucasian subjects and have found that major adaptations include a lowered resting heart rate, increased stroke volume, improved limb blood flow and limb vasodilatory capacity, and a decrease in arterial stiffness.[9] autonomic adaptations include increased vagal tone and baroreflex sensitivity.[9,11] several studies that have been conducted in older african populations suggest that regular exercise has beneficial cardiovascular effects and may decrease the risk for cardiac complications.[10] there are fewer studies conducted among young populations in general,[2] and little is known about the cardiovascular and autonomic effects of habitual exercise in young healthy african subjects. knowing that black africans are at an increased risk of cardiovascular disease, and that younger populations in general are increasingly being affected by metabolic disease, it becomes important to establish if physical activity infers similarly protective adaptations in young black subjects as it does in older black and caucasian populations. as such, the purpose of this study was to investigate the effect of habitual physical activity in young healthy black african males by documenting changes in autonomic and haemodynamic markers after a 20-week exercise intervention. markers monitored were those tested in previous studies investigating the effect of exercise on cardiac and autonomic function and included: aerobic capacity (vo2 max), systolic blood pressure (sbp), diastolic blood pressure (dbp), sajsm vol. 27 no. 2 2015 29 mean arterial blood pressure (map), blood pressure varibilty (bpv), cardiac output (co), stroke volume (sv), heart rate (hr), total peripheral resistance (tpr), ejection fraction (ejt), ascending aorta impedance (zao) and arterial compliance (cwk). it was hypothesised that 20 weeks of graduated exercise training would result in significant changes in the stated markers of autonomic hemodynamic regulation. methods subjects fifty-five male participants (aged 18 22 years) enrolled for basic training at the south african national defence force (sandf) were included in the study. of the 55 males, 54 were black and 1 was of mixed race ethnicity. all participants had undergone mandatory physical examination and had been cleared to participate in intense physical activity. exclusion criteria were a history of cardiovascular, hepatic, respiratory, renal, pulmonar y, metabolic, or orthopaedic disease requiring medical attention, as well as any respiratory tract infection in the previous 2 weeks and use of any medication that could influence cardiovascular control. although smoking was not an exclusion criteria, smoking history was recorded preand post-intervention, and none of the subjects reported a change in smoking habits. physical characteristics of the participants are shown in table 1. no professional athletes or highly trained individuals were included in this study. baseline training status of participants var ie d f rom s e dent ar y to inf re quent recreational exercise training. after they were informed of the nature and aim of the study, all participants gave their written consent in accordance with ethics committee procedures at the university of pretoria. experimental protocol this was a prospective 20-week exercise intervention study with a self-control design. the study protocol was submitted to and approved by the university of pretoria ethics committee. the recording of cardiovascular variables was performed at week 1 (baseline) and again at week 20. no exercise was performed in the 24 hours preceding the testing and participants rested for a 10-minute period before the testing. during the data sampling, participants were asked to remain as still and quiet as possible. this occurred in the absence of external auditory or visual stimuli. room temperature was maintained at 20 22°c. sampling was done at 823 m above sea level. blood pressure was then continuously sampled for 10 minutes in a supine position, of which the last 5 minutes of sampling were used for data analysis. all participants that started the study completed the intervention and were retested at week 20. the participants acted as their own control group as week 20 results were compared with baseline results. exercise training programme the basic training programme conducted by the sandf includes elements of aerobic and resistance training, as well as technical military skills training (table 2). the primary aim of the programme was to develop basic fitness components such as cardiorespiratory and muscular endurance. physical training includes upper and lower body strength, endurance and stretching exercise, as well as interval training and sustained marching or jogging for cardiovascular endurance. technical skills training included drills, regimental asp ects, compliments and saluting, musketry, shooting, signal training, mine awareness, map reading, buddy aid, field craft, water orientation, and parade rehearsal. the programme is progressive in intensity and duration, escalating at weeks 4, 6, 7, 11 and finally at week 13. the calculated average basal metabolic rate (bmr) for participants, in addition to the energy expenditure of the training and exercise activities, resulted in a calculated average energy consumption of approximately 8 485 kj/day, which can be classified as a medium to high intensity exercise programme.[12] although other prospective exercise intervention studies vary from 6 weeks[13] to 5 years,[11] a 20-week exercise regimen was chosen for this study as this is the duration of the basic training programme undertaken by the sandf. measurements the finometer pro (finapres medical systems, the netherlands) was used for data sampling. the finometer pro monitors blood pressure (bp) non-invasively with a volume clamp that is placed on the finger. when the volume clamp is activated the intra-arterial pressure equals that of the finger cuff pressure. transmural pressure changes are obser ved and evaluated by a computer a lgor it hm. the finapres automatically tracks changes in the size of the arterial vessels caused by changes in the smooth muscle tone and makes available a calibrated pressure waveform which is interpreted by a pattern recognition table 1. physical characteristics and anthropometry of participants (week 1) mean (sd) age (yr) 20.9 (1.2) height (cm) 171.0 (7.1) mass (kg) 62.9 (7.2) bmi (kg/cm2) 21.6 (2.1) ethnicity black 54 mixed race 1 table 2. pt programme component quantity pt periods 62 total physical training (h) 41 warm-up (min) 434 upper body muscle endurance exercises* 124 abdominal body muscle endurance exercises† 124 lower body muscle endurance exercises* 124 back exercises 64 upper body stretching‡ 62 lower body stretching‡ 124 back stretching‡ 62 jogging (min)§ 1 510 interval training (min)¶ 236 route march distance (km) 31 pt = physical training. * weeks 1 6 completed 2 sets of 10 12 repetitions. weeks 7 10 completed 3 sets of 10 12 repetitions. weeks 11 17 completed 3 sets of 12 15 repetitions. † weeks 1 11 completed 2 sets to maximum. weeks 12 17 completed 3 sets to maximum. ‡ each stretch 3 × 20 s. § weeks 1 3: 15 s walking/45 s jogging. weeks 4 and 5: 5 s walking/55 s jogging. week 6: 25 min jogging (× 2/week). weeks 7 12: 30 min jogging (× 2/week). weeks 13 17: 30 min jogging (× 4/week). ¶ week 7: 1 min slow jog/30 s sprint × 15 (× 2/week). week 8: 45 s slow jog/30 s sprint × 20 (× 2/week). week 9: 30 s slow jog/30 s sprint × 15 (× 2/week). week 10: 30 s slow jog/30 s sprint × 20 (× 2/week). week 11: 30 s slow jog/30 s sprint × 25 (× 2/week). week 12: 20 s slow jog/30 s sprint × 25 (× 2/week). 30 sajsm vol. 27 no. 2 2015 programme to provide sbp and dbp.[14] beatto-beat bp is then monitored over a chosen period. additional model-flow calculations provided information on sv, co and tpr. the 2010 finapres beatscope 1.1a software package (finapres medical systems, the netherlands) was used to quantify the following haemodynamic parameters: sbp, dbp, map and the variability (standard deviation, sd) of each, bp, co, sv, hr, tpr, ejt, zao and cwk. the finometer pro meets the association for the advancement of medical instruments accuracy requirements for automated sphygmomanometers, with the precision of results comparable with those published for auscultatory techniques.[15] the finometer is suitable for tracking blood pressure as within subject precision is high, 3.4 4.5 mmhg for sbp, 1.5 2.0 mmhg for mbp and 1.7 2.2 mmhg for dbp at a 95% confidence interval.[16] measurement of exercise ability/fitness was determined by indirect calculation of vo2 max using the validated 2.4 km run test.[17] statistical analysis as many of the variables follow a skew distribution, the results are reported using the median, interquartile range and the first and third quartiles. the wilcoxon signed rank test, which is analogous to a paired sample t-test, was used to assess differences between baseline and week 20. a p-value <0.05 was considered statistically significant. results the medians and quartiles of the cardiovascular and blood pressure variables evaluated are illustrated in table 3 and table 4 respectively. heart rate, stroke volume and cardiac output the basic training programme resulted in a significant decrease in median resting hr by 9 bpm over 20 weeks (p<0.01) (table 3). both sv and co showed a significant response to exercise intervention with an increase of 22% (p<0.01) and 9% (p<0.05) respectively. blood pressure and blood pressure variability values of sbp, dbp, map and the sd are shown in table 4. these results show that after a 20-week training programme, only dbp decreased (p<0.01). the changes in sbp and map were not statistically significant. bpv was assessed by using intraand interparticipant sd and coefficient variation of arterial blood pressure. although bpv did decrease in all measured variables, the change was not statistically significant. ejection fraction, total peripheral resistance, ascending aorta impedance and arterial compliance as illustrated in table 3, there were significant changes seen in ejt, tpr and zao (p<0.05) while cwk remained unchanged. aerobic capacity there was a significant (p<0.001) improvement in vo2 max after the 20-week training programme (table 3). although this study does not specifically focus on changes in vo2 max, it is important to document the training effect and consider all other results in the context of an improvement in aerobic capacity. discussion a significant improvement in several measurements of cardiovascular function occurred after a 20-week aerobic and resistance training programme in this young and healthy group of participants. long-term aerobic activity is associated with haemodynamic and physiological adaptations of the cardiovascular system.[1,2,9,10] the improvements in hr, sv, co and ejt in this study indicate improved cardiac efficiency and are consistent with other studies conducted in young, healthy subjects.[9] there are numerous studies documenting an increased sv after a prolonged exercise intervention in both older[18] and young, healthy subjects[9] but specific detailed studies on black africans are scant. vella and robergs[19] suggest that sv response to exercise is influenced by training status, age and sex, but fail to discuss the influence of ethnicity. the present study provides valuable evidence that prolonged exercise induces improvements in sv in subjects of black african ethnicity. table 3. comparison of week 1 and week 20 cardiovascular variables measurements (supine) indicator week 1, median* (n=55) week 20, median* (n=55) p-value weeks 1 20 vo2 max (ml/kg/min) 55.68 (53.74 58.09) 58.15 (57.16 60.39) <0.001† hr (bpm) 69.61 (64.52 77.64) 60.89 (54.32 67.89) <0.001† sv (ml/beat) 67.98 (56.35 77.80) 82.22 (74.05 96.04) <0.001† co (lpm) 4.47 (3.73 5.50) 4.88 (4.45 5.95) 0.039‡ ejt (units) 0.33 (0.31 0.34) 0.34 (0.32 0.34) 0.002‡ tpr (mmhg/min/l) 1.05 (0.83 1.37) 0.94 (0.76 1.04) 0.003‡ zao (mmu) 52.92 (51.43 55.70) 52.19 (50.44 54.49) 0.002‡ cwk (mu) 2.53 (2.35 3.03) 2.57 (2.28 3.17) 0.186 mu = medical unit (mmhg.s/ml)* 25th 75th percentile. † p<0.001. ‡ p<0.05 (a priori statistical significance for all tests was set at p≤0.05). table 4. comparison of week 1 and week 20 blood pressure indices measurements (supine) indicator (mmhg) week 1, median* (n=55) week 20, median* (n=55) p-value weeks 1 20 sbp 101 (91 111) 103 (97 110) 0.186 dbp 65 (60 71) 60 (57 68) <0.001† map 79 (73 85) 76 (72 82) 0.134 map sd 4.7 (4.2 5.8) 4.4 (3.7 5.2) 0.067 sbp sd 6.1 (4.8 7.4) 5.8 (4.9 7.4) 0.688 dbp sd 4.5 (3.8 5.3) 4.2 (3.5 4.9) 0.126 * 25th 75th percentile † p<0.001 (a priori statistical significance for all tests was set at p≤0.05). sajsm vol. 27 no. 2 2015 31 improvements in aerobic fitness (measured by vo2 max) are associated with a decreased relative cardiovascular risk profile.[8] in this group of healthy subjects, vo2 max increased by 4% between week 1 and week 20. other studies conducted in young, healthy, non-african subjects have shown greater improvements in vo2 max following an exercise intervention,[20] while a study conducted in young normotensive african-american men (aged 18 26 years) showed a 16% improvement in aerobic capacity following an 8-week aerobic training programme.[1] the main differences between this study and other studies was the baseline average body mass index (bmi) of subjects (21.6 kg/cm2 compared with 25.0 kg/cm2[1] and 25.3 kg/cm2[20]) and the type, duration and intensity of training performed (mixed resistance and aerobic training at medium to high intensity for 20 weeks v. aerobic training at high intensity for 6 days[20] and 8 weeks[1]). regular exercise is associated with a beneficial vascular profile.[8] the present study demonstrates that prolonged regular exercise causes beneficial changes in central (zao) and peripheral (tpr) vasculature in young african males. studies that have evaluated the effect of exercise on vasculature indeed show beneficial changes in both older[5,8] and younger participants,[5] with the effect of exercise on tpr and zao being seen as early as 4 6 weeks in young, healthy participants.[13] no change in cwk was demonstrated in this study. this is consistent with a previous study conducted on young (22-yearold) african-american men, which showed no change in central artery stiffness after 6 weeks of training.[2] age has been identified as a determinant of arterial response to exercise, with younger subjects showing a greater response at peripheral vessel level, while older subjects experience predominant changes in large arteries.[5] this may explain the results of the present study, which shows a change in arterial zao, but not cwk. the results suggest that cwk is well maintained at a young age regardless of training status or aerobic fitness. epidemiological studies show there is a higher incidence of hypertension in black african populations compared with causasian populations and that exercise may play a beneficial role in reducing this incidence.[4] we hypothesised that a 20-week training programme would have improved blood pressure variables when compared with week 1, instead we found that sbp and map remained unchanged, and only the decrease in dbp was statistically significant (table 4). week 1 measurements of resting blood pressure showed that only one participant had an elevated sbp (152 mmhg). by week 20, the maximum sbp recorded was 131 mmhg. other than this isolated elevated initial sbp, all participants were normotensive before the intervention. most studies that investigate the relationship between exercise and cardiovascular efficiency have been conducted on older populations and many show significant decreases in both sbp and dbp.[21] in the few studies that have been conducted among young healthy populations, these changes are less dramatic. as in the present study, differences may only be seen in dbp,[5] and in some cases no change was seen across any of the blood pressure indicators,[13] which may suggest that either changes in blood pressure may be dependent on age[5] or that the margin for improvement in normotensive patients is narrower than in hypertensive patients. bpv reflects vascular autonomic function and is a recognised marker of cardiovascular health.[22] studies have shown an elevated bpv to be an independent predictor of cardiovascular mortality. [22] in this group of participants, bpv did not change significantly after 20 weeks of training. our findings differ from a previous study on young normotensive males, which demonstrated significant improvement in autonomic blood pressure control systems following an 8-week exercise intervention.[1] the difference in outcome between the bond et al.[1] study and the present study could be attributed to the pre-intervention physical activity level of the participants. the subjects in both studies were of similar mean (sd) ages (20 (2) years compared with 21 (1) years in the present study); however in the bond et al.[1] study,the participants were only included with the criterion that they did not participate in regular exercise during the previous year while our study included subjects with variable training history. it is also possible that improvements in autonomic modulation of blood pressure are best appreciated during physical or mental stress testing rather than at rest; some changes may have been seen if stress testing was included in this study protocol. in other studies that have shown a decreased bpv (and increased baroreceptor sensitivity) after prolonged training, participants were either all over the age of 40 or had comorbid illnesses.[23] as such it is plausible that in a young, healthy population, good autonomic modulation is preserved and the margin for improvement with exercise will always be limited and seldom be significant. conversely, in an elderly population or in a population with comorbidities affecting the cardiovascular system, such as diabetes or recent myocardial infarction, sustained exercise causes numerous beneficial changes to vasculature and neural modulation, which cumulatively result in a significant decrease in bpv post intervention.[22] there are, however, a minority of studies that demonstrate no significant change in bpv following low intensity regular exercise in the elderly.[11] in these studies that showed no change in bpv, the participants tested had no comorbidities, corroborating the theory that a lack of comorbid illness could influence the amount of change expected from an exercise intervention. study limitations this study was designed as a self-control study. it may have been strengthened by inclusion of a control group to verify that changes seen were solely due to the intervention. the study was conducted on army recruits who were subjected to a 20-week training programme that increased in dose from week to week. results are only reported for week 1 and week 20, giving no insight to what happened during this period. as such, one cannot differentiate the effects of duration of training from the dose of training. finally, it may have been valuable to include physical or mental stress tests as a final means of validating any changes in markers of autonomic blood pressure control such as bpv. conclusion this study contributes to the growing pool of research conducted among healthy, young individuals providing insights to how ethnicity may or may not influence findings. the findings in this study suggest that exercise improves the vascular profile among african men even at a young age. changes in co, sv, tps, ejt and cwk suggest a favourable response to exercise and a reduced risk for cardiovascular disease. the fact that sbp and the variability indicators (sbp sd, dbp sd) remained unchanged is most likely related to the age, general health status and pre-intervention training status of the participants. results suggest that young age and lack of comorbidity decreases variance in bpv after a training intervention. further cross-sectional studies among trained 32 sajsm vol. 27 no. 2 2015 and untrained youths need to be conducted to corroborate this theory. previous research suggests that even small changes in cardiovascular indices sustained over a prolonged period will be beneficial to overall and long-term wellbeing. the findings in this study, in conjunction with all research cited in this article, can be used as evidence to support life-long aerobic exercise as a possible non-pharmacological cardioprotective therapy in subjects of all ethnic groups. acknowledgements. lt col e terblanche, wing commander: research and development joint physical training, sport and recreation training centre, south african national defence force. references 1. bond v, bartels mn, sloan rp, et al. exercise training favourably affects autonomic and blood pressure responses during mental and physical stressors in africanamerican men. j hum hypertens 2009;23(4):267-273. [http://dx.doi.org/10.1038/ jhh.2008.125] 2. heffernan ks, fahs ca, iwamoto ga, et al. resistance exercise training reduces central blood pressure and improves microvascular function in african american and white men. atherosclerosis 2009;207(1):220-226. [http://dx.doi.org/10.1016/j. atherosclerosis.2009.03.043] 3. swift dl, johannsen nm, lavie cj, et al. racial differences in the response of cardiorespiratory fitness to aerobic exercise training in caucasian and african american postmenopausal women. j appl physiol 2013;114(10):1375-1382. [http:// dx.doi.org/10.1152/japplphysiol.01077.2012] 4. heffernan ks, jae sy, vieira vj, et al. c-reactive protein and cardiac vagal activity following resistance exercise training in young african-american and white men. am j physiol regul integr comp physiol 2009;296(4):r1098-r1105. [http://dx.doi. org/10.1152/ajpregu.90936.2008] 5. mcdonnell bj, maki-petaja km, munnery m, et al. habitual exercise and blood pressure: age dependancy and underlying mechanisms. am j hypertens 2013;26(3):334-341. [http://dx.doi.org/10.1093/ajh/hps055] 6. assah fk, ekelund u, brage s, mbanya jc, wareham nj. urbanization, physical activity, and metabolic health in sub-saharan africa. diabetes care 2011;34(2):491496. [http://dx.doi.org/10.2337/dc10-0990] 7. price jh, khubchandani j, mckinney m, braun r. racial/ethnic disparities in chronic diseases of youths and access to health care in the united states. biomed res int 2013;article id 787616:12 pages. [http://dx.doi.org/10.1155/2013/787616] 8. thijssen dh, maiorana aj, o’driscoll g, cable nt, hopman mt, green dj. impact of inactivity and exercise on the vasculature in humans. eur j appl physiol 2010;108(5):845-875. [http://dx.doi.org/10.1007/s00421-009-1260-x] 9. heydari m, boutcher yn, boutcher sh. high-intensity intermittent exercise and cardiovascular and autonomic function. clin auton res 2013;23(1):57-65. [http:// dx.doi.org/10.1007/s10286-012-0179-1] 10. prista a, macucule cf, queiroz ac, et al. a bout of resistance exercise following the 2007 aha guidelines decreases asleep blood pressure in mozambican men. j strength cond res 2013;27(3):786-792. [http://dx.doi.org/10.1519/jsc.0b013e31825d9783] 11. uusitalo alt, laitinen t, vaisanen sb, lansimies e, rauramaa r. physical training and heart rate and blood pressure variability: a 5-yr randomized trial. am j physiol-heart circ physiol 2004;286(5):h1821-h1826. [http://dx.doi.org/10.1152/ajpheart.00600.2003] 12. foss ml, keteyian sj. fox’s physiological basis for exercise and sport. 6th ed. iowa: mcgraw-hill, 1998. 13. parshad o, richards a, asnani m. impact of yoga on haemodynamic function in healthy medical students. w indian med j 2011;60(2):148-152. 14. langewouters gj, settels jj, roelandt r, wesseling kh. why use finapres or portapres rather than intraarterial or intermittent non-invasive techniques of blood pressure measurement? j med eng technol 1998;22(1):37-43. [http://dx.doi.org/10.3109/03091909809009997] 15. guelen i, westerhof be, van der sar gl, et al. finometer, finger pressure measurements with the possibility to reconstruct brachial pressure. blood press monit 2002;8(1):2730. [http://dx.doi.org/10.1097/00126097-200302000-00006] 16. imholz bp, weiling w, langewouters gj, montfrans ga. continuous finger arterial pressure: utility in the cardiovascular laboratory. clin auton res 1991;1(1):43-45. [http://dx.doi.org/10.1007/bf01826057] 17. burger sc, bertram sr, stewart ri. assessment of the 2.4 km run as a predictor of aerobic capacity. s afr med j 1990;78(6):327-329. 18. cornelissen va, goetschalckx k, verheyden b, et al. effects of endurance training on blood pressure regulation, biomarkers and the heart in subjects at a higher age. scand j med sci spor 2011;21(4):526-534. [http://dx.doi.org/10.1111/j.16000838.2010.01094.x] 19. vella ca, robergs ra. a review of stroke volume response to upright exercise in healthy subjects. br j sport med 2005;39(4):190-196. [http://dx.doi.org/10.1136/ bjsm.2004.013037] 20. astorino ta, allen rp, roberson dw, jurancich m. effect of high-intensity interval training on cardiovascular function, vo2 max, and muscular force. j strength cond res 2012;26(1):138-145. [http://dx.doi.org/10.1519/jsc.0b013e318218dd77] 21. davis wj, wood dt, andrews rg, elkind lm, davis wb. concurrent training enhances athletes’ strength, muscle endurance, and other measures. j strength cond res 2008;22(5):1487-1502. [http://dx.doi.org/10.1519/jsc.0b013e3181739f08] 22. galetta f, franzoni f, platinga y, et al. ambulatory blood pressure monitoring and endothelium-dependent vasodilation in the elderly patients. biomed pharmacother 2006;60(8):443-447. [http://dx.doi.org/10.1016/j.biopha.2006.07.013] 23. spierer dk, demeersman re, kleinveld j, et al. exercise training improves cardiovascular and autonomic profiles in hiv. clin j auton res 2007;17(6):341-348. [http://dx.doi.org/10.1007/s10286-007-0441-0] km_c227-20180711130325 sajsm 595 (commentarty).indd commentary 1 sajsm vol. 30 no. 1 2018 preventing the seemingly unpreventable – challenging the return-to-play criteria for recurrent hamstring strain prevention n craddock , bsc (physiotherapy), k buchholtz, mphil (sports physiotherapy) division of physiotherapy, department of health and rehabilitation sciences, university of cape town, old main building, groote schuur hospital, anzio road, observatory, cape town, south africa corresponding author: n craddock (crdnic004@myuct.ac.za) hamstring strains are one of the most common injuries in sport, [1] particularly in field sports such as soccer. [2] despite ongoing research within injury prevention and management of this condition, there is an increasingly high rate of recurrence of hamstring strains. [1] some of the questions that need to be considered are: is this due to ineffective or incomplete rehabilitation? or is it due to inadequate return-to-play guidelines? a hamstring strain has two main mechanisms of injury. the first mechanism of injury occurs following a forceful eccentric contraction at a high speed, during the late swing phase of the running gait cycle. the second mechanism of injury occurs when the hamstring muscle is stretched beyond its available range of motion or load tolerance. [1,3] besides hamstring strains being classified according to the mechanism of injury, they can also be classified into three different grades, depending on the degree of severity of the injury. this gives practitioners information regarding the size of the tear, the amount of pain and potential loss of function. [1,3] additionally, they may be described based on the location in the specific hamstring muscle affected. [2] discussion while studies thus far have proposed various return-to-play criteria following hamstring strains, the validity and reliability of these criteria have not been established. careful consideration of the current literature [1,2,6] has suggested the best return-to-play criteria for athletes post hamstring strains as follows: on examination of the injured player there should be no pain on local palpation or during strength testing, with a maximum of ten percent difference in strength between the injured and uninjured limb. active and passive hamstring flexibility should demonstrate a less than ten percent difference in range between the injured and uninjured side. there should be no pain during functional performance (such as sports related movements to near maximum intensity/speed compared to pre-injury level) and no pain post functional testing. on-field testing should include repeated sprint ability tests, deceleration drills and single-leg bridging, depending on the specifics of the sport. [1,6] longer return-to-play times have been associated with increased pain on the initial examination, increased pain and weakness during midand outer-range strength testing, delayed start to rehabilitation, and pain with single-leg bridging. [2] it is important to first identify the potential risk factors for sustaining a hamstring strain. the literature states that the greatest risk factor for a hamstring strain is a previous hamstring strain. [1,3] the high rate of recurrence could be due to ineffective rehabilitation programmes, returning to sport too soon, or a combination of these and various other modifiable and non-modifiable risk factors. these include increased age, decreased flexibility, muscle imbalances and fatigue. [1,3] thus players are sustaining recurrent hamstring strains despite following rehabilitation protocols. time-loss injuries are burdensome to athletes, their teammates and sporting coaches, with an average of 17 days lost to injury in rugby and 18 days lost to injury in soccer. [3] the psychological impact of sustaining an injury may drive athletes to return-to-play too quickly, in combination with perceived pressure from the team and staff, further increasing their risk of sustaining another injury. the risk factors discussed above are only a few of those that have been identified exhaustively in the literature. many other risk factors have been suggested but with less evidence to support their role in predisposing athletes to hamstring strains. these include poor lumbopelvic control/stability, inadequate warm-up, changes in muscle fibre composition following injury, an increased training volume or level of participation, neural tension and race. [1] despite the effort of rehabilitation programmes to address these risk factors, the rate of recurrent hamstring strains is still high (22%), particularly in the first two months following injury. [4] two protocols have been developed that have been shown to be effective in reducing the rate of new hamstring strains, as well as the rate of recurrence. these include the l-protocol and the nordic hamstring exercise protocol. the l -protocol, developed by askling et al. [4] consists of three exercises, namely, the extender, the diver and the glider. the aim of this protocol is to strengthen the hamstring muscles in a lengthened position and on contraction during lengthening (eccentric background: hamstring strains are one of the most common injuries in sport. previous injury has been found to be one of the greatest risk factors associated with recurrent hamstring strains. although rehabilitation programmes have been developed and implemented to aid safe and efficient return-to-play, the incidence of hamstring injuries has not decreased. discussion: as hamstring strains most commonly occur during the eccentric phase of muscle action, rehabilitation should focus on eccentric muscle strengthening. the l-protocol and the nordic hamstring exercise protocol strengthen the hamstring muscles eccentrically. they have been found to be effective in decreasing the incidence of new hamstring strains as well as the rate of recurrence. this commentary therefore aims to suggest changes to the return-to-play criteria following hamstring strains to prevent the seemingly unpreventable. keywords: hamstrings, injury prevention, sports, eccentric movement s afr j sports med 2017; 30:1-2.doi: 10.17159/2078-516x/2018/v30i1a3401 http://dx.doi.org/10.17159/2078-516x/2018/v30i1a3401 commentary sajsm vol. 30 no. 1 2018 2 muscle action). in a study conducted on elite football players, the l-protocol was found to significantly decrease the returnto-play time in comparison to standard rehabilitation programmes, as well as reduce the rate of reinjury. [4] mechanistically this protocol makes sense, as the two mechanisms of injury occur whilst the hamstring is in a lengthened position and therefore under most tension. this is clearly the weakest point in the range and therefore exercises need to focus on strengthening the hamstrings in this outerrange to prevent injury. this protocol is easy to implement in practice and shows promise in terms of efficacy, and it may therefore be highly beneficial in terms of return-to-play criteria. the nordic hamstring exercise [5] has been implemented in various sporting populations worldwide. this single exercise protocol, which involves a controlled lowering of the trunk to the floor from a kneeling position, increases the eccentric strength of the hamstring muscle and thereby improving its ability to tolerate high loads while placed under stress. [5] in a study conducted by peterson et al. the nordic hamstring exercise has been shown to be effective in reducing the rate of overall, new and recurrent hamstring strains in both amateur and professional soccer players. [5] as the injury recurrence rate is high, and a previous injury is a risk factor for recurrent injury, preventative strategies are extremely important. while this exercise may be more difficult to implement in the non athletic population due to its relative degree of difficulty, it is likely to be an essential exercise in the athletic population due to the high demands placed on the body during competitive sport. no equipment is needed and it can be performed in pairs, making it a great team building exercise. the successful completion of the l-protocol or the nordic hamstring protocol should be included to the return-to-play criteria as evidence shows that these protocols significantly reduce the risk of reinjury. the average return-to-play time following correct execution of the l-protocol is 28 days this protocol should potentially be performed for a minimum of four weeks to be considered successful in its application. [4] the nordic hamstring protocol has been found to be effective when performed for a minimum of five weeks (known as the build up phase) and continued for a further five weeks [5]. implementing one of these protocols will provide clinicians with stronger outcome measures. however, successful completion of either protocol should be reviewed in conjunction with the clinically based return-to-play criteria. this is also important for physiotherapists to use their clinical reasoning skills to determine if a player is ‘fit’ to return-to-play. as evidence-based practitioners, it is necessary to provide the most up–to-date information, treatment and rehabilitation to patients and athletes. clinicians should not forget the psychological effects of an injury on a player and the setbacks that this may have on their confidence and performance. psychological readiness should be another key criterion for return-to-play. anxiety about reinjury may lead to fear avoidance or altered patterns of behaviour, thus it is essential that the player is deemed both psychologically as well as physically fit to return-to-play. [6] rehabilitation is a holistic approach. it is important that all aspects of rehabilitation are covered in order to return the player to his/her optimal level of functioning. if an athlete is returned to play too soon their risk of reinjury increases, especially in the first two months of competition and training when they are most vulnerable. delayed rehabilitation may paradoxically also be a risk factor. early mobilisation and rehabilitation within safe limits should be prioritised, whilst ensuring that the rehabilitation programmes are completed in full. a conscientious decision must be made solely with the best interest of the player in mind despite pressures from outside forces, such as coaches, team managers and the media. further research is recommended to determine whether these rehabilitation protocols are being implemented correctly, whether players are complying with the full rehabilitation protocols, and if graduated sport-specific return-to-play programmes are being undertaken. conclusion failure of the hamstring muscles occurs regularly during the eccentric phase of the gait cycle in running or muscle contraction; therefore the focus of rehabilitation programmes should be on eccentric hamstring strengthening. the successful completion of either the l-protocol or the nordic hamstring protocol should be considered as a main criterion for return-toplay, in conjunction with the current clinically-based return to sport criteria. as mentioned above, evidence has shown that these protocols significantly reduce the rate of injury and reinjury. further research is needed to determine both compliance and completion of return-to-play protocols following hamstring injuries. conflict of interest: none acknowledgements: the uct division of physiotherapy is thanked for the opportunity and guidance in writing this commentary for publication. references 1. erickson ln, sherry ma. rehabilitation and return to sport after hamstring strain injury. j sport health sci 2017;6(3): 262270. [doi:10.1016/j.jshs.2017.04.001] 2. jacobsen p, witwrouw e, mutart p, et al. a combination of initial and follow-up physiotherapy examination predicts physician-determined time to return to play after hamstring injury, with no added value of mri. br j sports med 2016;50(7):431-439. [doi:10.1136/bjsports-2015-095073] 3. liu h, garrett we, moorman ct, et al. injury rate, mechanism, and risk factors of hamstring strain injuries in sports: a review of the literature. j sports health sci 2012;1(2):92-101 [doi: 10.1016/j.jshs.2012.07.003] 4. asklin cm, tengvar m, thorstensson a. acute hamstring injuries in swedish elite football: a prospective randomised controlled clinical trial comparing two rehabilitation protocols. br j sports med 201347(15):953-959. [doi:10.1136/bjsports-2013092676] 5. peterson j, thorborg k, nielson mb, et al. preventive effect of eccentric training on acute hamstring injuries in men’s soccer: a cluster-randomized controlled trial. am j sports med 2011;39(11):2296-2303. [doi:10.1177/0363546511419277] 6. van der horst n, backx f, goedhart ea, et al. return to play after hamstring strain injuries in football (soccer): a worldwide delphi procedure regarding definition, medical criteria and decision-making. br j sports med 2017; 51(22): 1583-1591. [doi: 10.1136/bjsports-2016-097206] https://doi.org/10.1016/j.jshs.2012.07.003 https://doi.org/10.1016/j.jshs.2012.07.003 we are in the midst of an exponential growth of access to information. in particular, the development of the internet has been paralleled by the ease of setting up a blog which assumes some status of authority among the readers and contributors. now anyone who has access to a computer and the internet can write on a topic and contribute their viewpoint to a discussion. apart from the censure of bad or inflammatory language, viewpoints can be displayed freely. this free communication has many advantages and perhaps helps to contribute to the acceptance of a wider range of ideas and tolerance for varying viewpoints. however, this proliferation of information has introduced new challenges to us. in the past we could consult printed media and, with a relatively high degree of confidence, accept that the information came from a legitimate source. now one assumes that at one’s peril! instinctively we have to be more vigilant and interrogate information more carefully. however, i do not see this as a problem, as it encourages us to go back to first principles. as the south african journal of sports medicine is written for health professionals from different disciplines who are attempting to have an evidence-based approach to their work, i thought it was a good idea to revisit some of the first principles which govern our work. an evidence-based approach assumes that the work has a scientific foundation. by definition, a scientific approach is based on logical principles derived from well-controlled experimentation. a feature of this approach is that it should be able to stand up to critical scrutiny. this is how the process of science works, and how knowledge slowly accumulates. to assist with screening the accuracy of new information i would like to suggest a few questions we can ask ourselves as a reflex action whenever we are evaluating new information: does the information portrayed in the article sound too good to be true? for example, does the product discussed promise quick improvement in health and fitness without requiring any major lifestyle changes? if this is the case alarm bells should ring. progress in science works at a snail's pace. it may take a paper a year to get published after it has been accepted for publication by a journal. often unpublished data are presented at conferences, so these data may take even longer to reach the printed form. therefore any claims of a ‘eureka-type’ finding should be viewed with caution. our understanding of physiology and biochemistry has evolved to the point where we have passed the stage where there will be sudden breakthroughs in knowledge which will have a sudden, dramatic impact on health and fitness. when exercise science and sports medicine were flourishing as an independent discipline in the early 1980s, it was common for breakthroughs in knowledge which resulted in major effects on health or performance. popularising the ergogenic effects of carbohydrate supplementation during endurance exercise is one of these examples. tapering after a period of hard training before competition is another example of knowledge in an area accumulating rapidly and having a significant impact on performance. this does not mean that progress in the acquisition of new knowledge has ended; it just means that steps in progress will be smaller and less noticeable than previously, when the discipline of exercise science and sports medicine was on the steep part of the development curve. when examining the original data described in the article, are the research subjects involved in the experiment the same type of subjects that the data are likely to be applied to? this may sound like a rather logical assumption but it has been violated several times previously. for example, some of the early studies on protein supplementation were done on malnourished individuals. of course these individuals would flourish after receiving a protein supplement, in contrast to the results one would observe in a well-nourished and healthy person. this however did not prevent the manufacturers of the supplement from capitalising on the results and marketing the product in a healthy population. there are many other examples in the fitness industry where untrained people are shown to have dramatic changes after being exposed to a gimmicky training programme. it stretches the believability factor to assume that highly trained individuals will respond to the same training stimulus in the same way. nevertheless this trick has been used successfully in the past and made some businesses large amounts of money. are there dogmatic statements in the conclusions of the paper? anyone involved in science will know that there are risks associated with being dogmatic about data! as a student i was taught by one of the top exercise scientists in the world that in the future 50% of our current knowledge will be shown to be incorrect. he continued with a wry smile by saying that unfortunately we don't know which 50% it will be! therefore treat anyone with a dogmatic belief with caution. they clearly have something to gain from their beliefs – either financial or ego! therefore, the skills needed by someone trying to critically evaluate a contemporary topic should be refined and developed. access to information is no longer the limiting factor. synthesising the information is now the distinguishing factor between someone who has a true understanding and ability to apply the information in an evidence-based way, compared with someone who attempts, but fails to apply their knowledge in an evidence-based way. we welcome the reader to the first edition of 2009! the goal of this journal is to contribute to the dissemination of information. all papers are peer-reviewed and are required to fulfill requirements which contribute to this goal. this is the first edition in which we have implemented the new guidelines for authors (page 31). we are committed to ensure that the information is communicated in a responsible way. we encourage all the scientists and practitioners involved in health and fitness to contribute to this goal by submitting a paper which may make a contribution. in the past the ability to contribute to the south african journal of sports medicine may have been biased towards academics and scientists. however, we have introduced two new categories (commentary and case studies) which will cater for practitioners who may not be in a position to conduct a formal study. much of our current knowledge has been ignited by case studies which are sometimes the catalyst for further investigation in a more systematic manner. just think how gratifying it will be for the author if in the future a research paper or textbook is written on a topic which at present is undefined, but described in a case study published in the south african journal of sports medicine! mike lambert editor-in-chief proliferation of information – the good the bad and the ugly a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial � sajsm vol �1 no. 1 �009 discussions about evidencebased practices in sports medicine often include the question whether practitioners who interact regularly with athletes should be guided by science, or whether scientists should take heed of what these experienced practitioners are doing and then set out to prove whether their approach is beneficial or not. as far as i am concerned the answer is a no-brainer. my view is based on the fact that there are well over 70 international journals dedicated to sports medicine/exercise science. the top journals publish over 100 papers per year. while many of these research studies fall into the category of ‘basic science’, with limited applicability for reducing the risk of injury or improving performance, many studies have outcomes which are applied and can guide clinical practice. most top quality journals have a section at the end of each paper which highlights and summarises the practical applications of the study. there is so much information on a variety of topics in sports medicine and exercise science that any treatment or intervention can be guided by evidence derived from experimentation. however, this view of science guiding practice is not shared by everyone. this is demonstrated by the gap which exists between the evidence derived from experimentation and the practice of some support staff when dealing with athletes. consider for example the practice of cold water immersion after training and competition. a recent survey showed that 83% of the support staff of elite rugby players in south africa used cold-water immersion for managing recovery after matches. 1 this practice occurs despite the evidence from a variety of studies being equivocal 2 or even negative from an adaptation perspective. 3 another example is the use of anti-inflammatory drugs where the use of these drugs for muscular injury far exceeds the recommendations based on scientific evidence. 4 does this mean that the quality of the science is poor and does not mimic the ‘reallife’ conditions, or does it mean that the practitioners have their own agenda which occurs independently of scientific findings? the answer to this question needs some debate – failure to close the gap between science recommendations based on a scientific approach and the actual practice of the support staff will impede development and deprive the athlete of the best available treatment. on another note, this first edition of the journal in 2010 brings about the changing of the guard. we have to bid farewell to the editorial board who have served the journal in an admirable way for 12 years. our sincere thanks go to professors maurice mars, yoga coopoo, kathy myburgh, tim noakes, geoff rogers and kit vaughan, who have contributed to the journal in various ways. their collective wisdom, experience and status have made a valuable contribution to the development of the journal. the new guard has a tough act to follow! we welcome to the editorial board the new members dr kerith aginsky (university of the witswatersrand), dr theresa burgess (university of cape town), dr richard de villiers (drs van wageningen and partners, somerset west), dr lize havemann-nel (north west university), dr christa janse van rensburg (university of pretoria), dr louis holtzhausen (university of the free state), professor frank marino (charles sturt university, australia) and dr babette pluim (royal netherlands lawn tennis association, netherlands). the collective skill of this group should serve the next phase well, as the journal develops further and meets the changing demands of the profession. with the new editorial board we also have a new relationship with the british journal of sports medicine. this relationship allows us to publish ‘editor’s choice’ articles which have previously been published in the british journal of sports medicine. we have included two such papers in this edition of the journal (‘non-steroidal anti-inflammatory drugs in sports medicine: guidelines for practical but sensible use’, and ‘eccentric loading for achilles tendinopathy strengthening or stretching?’) – both papers are excellent and make a valuable contribution to narrowing the gap between science and practice, as discussed above. mike lambert editor-in-chief references 1. van wyk dv, lambert mi. recovery strategies implemented by sport support staff of elite rugby players in south africa. south african journal of physiotherapy 2009; 65(1):1-6. 2. bleakley cm, davidson gw. what is the biochemical and physiological rationale for using cold-water immersion in sports recovery? a systematic review. br j sports med 2010; 44(3):179-187. 3. yamane m, teruya h, nakano m, ogai r, ohnishi n, kosaka m. postexercise leg and forearm flexor muscle cooling in humans attenuates endurance and resistance training effects on muscle performance and on circulatory adaptation. eur j appl physiol 2006; 96(5):572-580. 4. paoloni ja, milne c, orchard j, hamilton b. non-steroidal anti-inflammatory drugs in sports medicine: guidelines for practical but sensible use. br j sports med 2009; 43(11):863-865. narrowing the gap between science and practice a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial 2 sajsm vol 22 no. 1 2010 original research 1 sajsm vol. 29 2017 attitudes towards nutritional supplement use amongst adult gymnasium users in johannesburg north x mc creanor, bed fet, ba (hons) human movement science, mphil sport science; y coopoo, dphil, facsm and g gabriels, phd department of sport and movement studies, faculty of health science, university of johannesburg, gauteng, south africa corresponding author: y coopoo (yogac@uj.ac.za) concern has been raised in the south african health industry regarding the use of unregulated nutritional supplementation in sport.[1] while manufacturers use marketing to promote the value of supplements towards the maintenance of good health, the consumer’s focus should be more on awareness, education, and the improvement of health.[1] moreover, a study conducted by block et al. [2] found that users who consumed a wide selection of nutritional supplements on a daily basis were more prone to have optimal concentrations of chronic disease-related biomarkers, and be less prone to suboptimal nutrient concentrations, high blood pressure and diabetes when compared to non-nutritional supplement users.[2] the study by van der merwe and grobbelaar tested for testosterone and nandrolone prohormones, various ephedrines and caffeine in supplements.[3] they concluded that 18 (60%) contained non-prohibited supplements, and 12 (40%) of the supplements tested positive for numerous prohibited substances.[3] the authors state that these contaminated supplements pose a major concern for the health of their users, including the possibility of allergies to banned substances.[3] similar work by geyer et al. provides evidence for the health risks from these supplements.[4] out of the 634 samples analysed in this study, 15% contained banned substances not declared on the label.[4] in south africa, users of such supplements may be in contravention of the south african institute for drug-free sport’s regulations (saids). saids’ 2014 annual report states that it is the statutory body that promotes participation in sport which is free from the use of prohibited performance enhancing substances or methods that artificially enhance performance.[3] linked to this statement is the study by morrison et al. which indicated that 85% of participants consumed supplements ethically.[5] in this study, the consumption categories and usage of at least five times per week were multivitamins (45%), protein shakes (42%), vitamin c (35%) and vitamin e (23%).[5] this present study investigated the attitudes towards nutritional supplements in commercial gymnasium patrons in the johannesburg north region with respect to their use, acquisition of information and knowledge of the supplement, their reasons for going to a gymnasium, attitudes towards the supplement’s consumption, and types of products consumed. methods the study’s design is a quantitative cross-sectional design. a self-administered questionnaire was approved by the university of johannesburg, faculty of health sciences research ethics committee (rec-01-144-2015). it was adapted and validated, based on a study undertaken by gradidge.[6] the study was conducted in the johannesburg north region at five selected reputable gymnasiums, and only focused on adult gym members. the sample was computed, based on the work of sekaran[7] was obtained by a systematic convenience sampling method, consisting of a total of 364 participants aged between 18-49 years who attend a gymnasium two or more times per week. prior to the commencement of completing the questionnaire, information about the study, anonymity and the option to refrain from answering the questionnaire if they so wished. aspects of the questionnaire made use of a 4 point background: nutritional supplements refer to a product ingested to increase the nutritional content of a normal diet, to fill a dietary need and/or presumed deficiency. the usage and popularity of nutritional supplements, however, raises concerns from a health benefit and risk perspective. in south africa, there is currently no adequate regulatory framework of enforcement for nutritional supplement products and undeclared constituents by the statutory body, the medicines control council (mcc). education awareness programmes by organisations that should take consumer protection and the general public health and wellness as a right, needs to be improved. objectives: to investigate the attitudes toward nutritional supplements by adult gym users from commercial gymnasiums in the johannesburg north region of south africa. methods: a cross-sectional quantitative design, using a selfadministered questionnaire was applied to 364 recruited study participants who attended commercial gymnasiums in johannesburg north. results: one hundred and fifty users (41%) claimed that they ‘always’ read the information about the nutritional values, benefits, and side effects of the supplements on the labels prior to use. three hundred and three users (83%) indicated that the number of users of nutritional supplements in gymnasiums is on the increase. two hundred and seventy-three (75%) of main information sources for nutritional supplements may be found on the internet, while 292 (80%) indicated the need for gymnasiums to provide educational programmes pertaining to nutritional supplement consumption. conclusion: gymnasium users are aware of the increase in nutritional supplement use in commercial gymnasiums. many of the users were unaware of the potential mislabelling and health concerns regarding these supplements. therefore there is a need for improved nutritional supplement education programmes and diligence at multiple levels. keywords: proteins, vitamins, peer pressure, unregulated, information sources, education s afr j sports med 2017;29:1-5. doi: 10.17159/2078-516x/2017/v29i0a1387 mailto:yogac@uj.ac.za http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1387 original research sajsm vol. 29 2017 2 likert scale that required participants to select from the range ‘strongly agree’ to ‘strongly disagree’, to specific statements. the principal investigator was available to provide clarity regarding the questions to the study’s participants, if necessary. data for the study were manually transcribed and independently validated using the windows-based microsoft ® office excel 2003 sp 1 (excel © 1985-2003 microsoft corporation). the statistical package for the social sciences (spss inc. version 16) was used to calculate the descriptive statistics. results demographic data gymnasium users in the johannesburg north area ranged from between 18-49 years (mean 27 years) of age. of the total of 364 participants, 205 (56%) were male and 159 (44%) were female. two hundred and nineteen (60%) of the participants indicated that they started using nutritional supplements between 13 -18 years (high school), 84 (23%) started at 10 12 years (primary school), while 62 (17%) were over 18 years old. these results indicate how early in life supplements were used by adolescents. nutritional consumption assessment three hundred and three (83%) of the participants indicated that users of nutritional supplements in gymnasiums is on the increase. their perception of increase usage was by observation while training at gymnasiums. two hundred and seventy (74%) of respondents believe that gymnasium users are pressurised to use nutritional supplements, as their training friends were taking supplements to improve performance and perceived recovery from training. this subtle peer pressure caused them to follow the usage pattern of their friends as they felt that they were not going to benefit as much as their peers did. two hundred and seventy-three respondents (75%) indicated that they were aware of supplements that are prohibited by the world anti-doping agency, and 91 (25%) indicated that they had no knowledge of prohibited supplements. sources of nutritional supplement information acquisition table 1 shows the categories of information acquisition for nutritional supplements for which the participants had the choice of multiple options. the findings in table 1 show that the main sources of information regarding nutritional supplements, in order of priority from the respondents, the internet (75%), pharmacists (67%), and books (66%). the provision of information on supplements which was least accepted by the respondents was information from parents (38%), siblings (37%), physicians (36%), and biokineticists (34%). reasons for going to the gymnasium fig. 1 illustrates that, according to the respondents, the main reason for attending gymnasiums is to gain muscle (56%). other reasons are to stay healthy (36%) and for crossfit training purposes (36%) respectively. swimming (30%), spiritual motives (30%) and aerobic exercise were lesser reasons for going to the gymnasium. attitudes towards nutritional supplement consumption by participants table 2 shows that the main reason why respondents consumed nutritional supplements was to be healthier (82%), and the least likely reason was as a result of peer pressure (54%). table 3 shows the nutritional supplements of choice by the respondents are proteins (84%), carbohydrates (72%), and vitamins (71%). the supplements consumed to a lesser extent table 1. sources of information regarding nutritional supplements source n yes (%) no (%) internet 370 75 25 pharmacists 371 67 33 books 370 66 34 personal trainer 372 59 41 newspapers 372 59 41 magazines 372 57 43 friend/training partner 373 48 52 journals 370 47 53 representatives from nutritional companies 370 47 54 information brochures 369 45 55 parents 371 38 63 siblings 370 37 63 physicians 371 36 64 biokineticists 371 34 66 n= total number of respondents, (%) = percentage of respondents fig. 1. reasons for going to the gymnasium. n= total number of respondents original research 3 sajsm vol. 29 2017 by the respondents are phedra-cut thermogenic aids (35%), bcaa (34%) and l-glutamine (33%). information on labels of products one hundred and forty-nine (41%) of the respondents (n=362), indicated that they ‘always’ read the nutritional value, benefits and side effects of the supplement on the labels before they used the supplements. one hundred and seventy-four (48%) indicated that they do this ‘sometimes’, and 40 (11%) indicated that they ‘never’ read the information on the labels. summary of attitudes towards the consumption of supplements in the gymnasium table 4 shows that 80% of the respondents indicated a need for gymnasiums to provide educational programmes pertaining to the use of nutritional supplements in gymnasiums, 73% of respondents indicated that gymnasium participants use supplements to enhance performance, and 70% of the respondents felt that there has not been sufficient reporting by the media with respect to the use of nutritional supplements. discussion the work of gabriels et al. shows that the nutritional supplement market remained robust throughout the global recessionary period of 2008 to 2009, as well as tremendous growth.[1] the gymnasium users in this study were aged 18 to 49–years-old. the study by fitzgibbon et al. showed that teenagers’ body-image discrepancy and social influences were among reasons for the use of supplements.[8] the above factors point to the impact of market exposure on the introduction to consumption of nutritional supplements. this concurs with this present study which shows that eighty-four (23%) of the gymnasium participants who first used supplements were between the ages of 10 to 12 years. this early exposure to supplements indicates an association of steroid use, concomitant with the use of nutritional supplements. [9,10,11] the study by van der walt and coopoo [12] concluded that coaches defended the practice of supplement use, as they stated that it helped to build relationships of trust with their athletes. coaches may thus contribute to the culture of why a large proportion of respondents (74%) in this study believe that they are pressurised into using nutritional supplements.[12] this pressure may have a causal impact regarding the ‘attitude profile’ highlighted in table 4. table 2. reasons why participants consume nutritional supplements reason n yes (%) no (%) to be healthier 219 82 18 assists me in coping with the stresses of muscle gains in the gymnasium 221 79 21 helps to improve the way i perform in the gymnasium 220 73 27 helps me to reach my personal goals 220 70 30 helps to reduce food cravings in order to decrease my body weight 221 62 38 i feel pressured by my peers 220 54 46 n= total number of respondents, (%) = percentage of respondents table 3. nutritional supplement consumption by gymnasium users supplement n yes (%) no (%) protein supplements (e.g. whey protein) 366 84 16 carbohydrate supplements (e.g. energade, powerade) 367 72 28 vitamins (a, b, b12, c, d and e) 365 71 29 creatine supplements (e.g. creatine monohydrate) 367 67 33 caffeine (e.g. redbull, guarana) 367 59 41 fish oil (e.g. omega 3 tablets) 365 37 63 cla (conjugated linoleic acid) weight loss supplements 366 36 64 phedra-cut thermogenic aid 365 35 65 branched-chain amino acids (bcaa) 366 34 66 l-glutamine 365 33 67 n= total number of respondents, (%) = percentage of respondents table 4. attitudes regarding supplement consumption in gymnasiums supplement n (%)* gymnasiums should offer educational programmes for gymnasium users on the use of supplements in gymnasiums 371 80 there are too many gym users using supplements to enhance their performance in gymnasiums 372 73 the use of nutritional supplements by gymnasium users has not been sufficiently reported in the media 372 70 many of my friends think it is acceptable to use nutritional supplements 367 60 there is a problem with nutritional supplement use in my gymnasium 370 60 i am sometimes tempted to use performance enhancing supplements 365 58 the use of performance enhancing supplements and nutritional supplements has increased in the last five years 371 43 i would never consider the use of any nutritional supplementation 372 40 i think it is always wrong to use nutritional supplements for gym purposes 372 34 some think gymnasium participants who want to reach their goals have to sometimes use performance enhancing supplements 372 32 i do not think it is fair to use performance enhancing supplements 370 16 if i do not take nutritional supplements, i will not be able to succeed in my performance because everyone else in the gym is using supplements 369 5 n= total number of respondents, (%)* =percentage of respondents who strongly agree/agree original research sajsm vol. 29 2017 4 the main source of information on nutritional supplements for gymnasium participants in this study was the internet (75%). this is in contrast to the findings of van der walt and coopoo which identified pharmacists to be the main source of this information.[12] the age group sampled in the study by van der walt and coopoo , however, was the parents of high school children, which may explain the difference in the study findings. the results in table 3 show that the nutritional supplements of choice by the respondents were proteins (84%), carbohydrates (72%), and vitamins (71%). this compares to similar consumption patterns found in the work of froiland et al., [13] showing vitamin and mineral supplements as the third largest over-the-counter supplement category.[13] one of the reasons presented in this study as to why the gymnasium respondents (70%) use protein supplements was to gain muscle thereby reaching one of their personal training goals. however, these consumers were unaware of the potential health risks of taking these supplements as pointed out by mottram [14] and mueller et al. [15] , who stated that animal and plant sources may also contain toxic chemicals. also, the excessive consumption of protein shakes can produce toxic effects that may lead to potential health problems, such as kidney disease, water retention and high levels of ketones in the body.[14,15] gabriels et al. state that performance enhancing supplements may cause health problems due to contamination and/or adulteration.[1] these studies are supported by evidence that the potential health risks are not necessarily apparent due to the non-declaration of all product ingredients on the label and associated warnings and side effects.[4] in this scenario, consumers are at risk, regardless of whether or not they read the labels before using the supplements. in these authors’ opinion, additional protein intake is unnecessary if a balanced diet is followed. furthermore, the evidence shows that there is poor knowledge regarding nutritional supplements and/or there is a need for an ‘attitude’ change towards meaningful awareness requirements with respect to intelligent nutritional supplement usage.[6] nutritional supplement usage begins in many cases at a young age (10 to 12 years), and continues into adulthood. this study’s findings point to the nutritional supplement industry sector which is unregulated and which may lead to a potential negative impact on the consumer’s health. there are many schools in gauteng that have a supplement shop on campus.[16] this sends mixed messages to school athletes. education is one of the ways to inform the public about the risks and benefits of supplement use. conclusion johannesburg north’s gymnasium participants are aware of the increase in nutritional supplement usage in gymnasiums. the most popular supplement used by gymnasium participants in this study was protein, for muscle gain. this may be the first indication of muscle dysmorphia. respondents cited their main source of information to be the internet and that few healthcare and wellness professionals are consulted for advice on nutritional supplements. this study shows that there is a deficiency in the knowledge of the participants with regard to most nutritional supplements. a health concern is that more than half of the participants in the study did not read product labels. the requirement for education and awareness programmes and information campaigns on the health risks of supplement use should be implemented or improved. study limitations the main limitation in all of the questionnaires was poor memory and truthfulness. recommendations educating gymnasium users and the general public about the health risks involved in taking nutritional supplements is essential, and ensuring that all consumers seek appropriate professional advice before consuming supplements. educational programmes on nutritional supplements and their potential health risks should be available in primary and high schools, and at tertiary institutions to assist potential gymnasium participants and the guardians of minors. gymnasiums should also offer educational classes to their patrons that focus on the moral and ethical use of nutritional supplements. future research similar gymnasium studies, using the self-administered questionnaire used in this study should be conducted throughout south africa. specific male and female assessments of ‘attitudes’ towards nutritional supplement use by adult participants at gymnasiums would be useful. this would assist in standardising the ‘attitudes’ towards supplement use at gymnasiums across the country. references 1. gabriels g, lambert m, smith p. information on nutritional supplement labels: time for legislation? south afr j clin nutr 2012; 25: 22-26[https://doi.org/10.1080/16070658.2012.11734398] 2. block g, jensen cd, norkus ep, et al. usage patterns, health, and nutritional status of long-term multiple dietary supplement users: a cross-sectional study, nutr j 2007; 6: 30 [doi.org/10.1186/1475-2891-6-30] 3. van der merwe pj, grobbelaar e. inadvertent doping through nutritional supplements is a reality: original research article. s afr j sports med 2004; 16 [http://dx.doi.org/10.17159/2078516x/2004/v16i2a180] 4. geyer h, parr mk, mareck u,et al.. analysis of non-hormonal nutritional supplements for anabolic-androgenic steroids results of an international study. int j sports med 2004; 25: 124129 [doi:10.1055/s-2004-819955] 5. morrison l, gizis f, shorter k. prevalent use of dietary supplements among people who exercise at commercial gym. int j sport nutr exerc metab 2004; 14: 481-488 [doi: 10.1123/ijsnem 14.4.481] 6. gradidge pj-l. the use of performance enhancing substances by adolescent male athletes in selected johannesburg boys’ high schools. unpublished masters thesis. university of witwatersrand, 2010. retrieve http://wiredspace.wits.ac.za/handle/10539/9001 (accessed 15th june 2017) 7. sekaran u. research methods for business: a skill-building approach 2nded. new york: john wiley & sons, 1992: 253 http://dx.doi.org/10.17159/2078-516x/2004/v16i2a180 http://dx.doi.org/10.17159/2078-516x/2004/v16i2a180 http://wiredspace.wits.ac.za/handle/10539/9001 original research 5 sajsm vol. 29 2017 8. fitzgibbon ml, blackman lr, avellone me. the relationship between body image discrepancy and body mass index across ethnic groups. obes res 2000; 8: 582-589. [doi: 10.1038/oby.2000.75] 9. dodge tl, jaccard jj. the effect of high school sport participation on the use of performance-enhancing substances in youth adulthood. j adolesc health 2006; 39: 367-373 [doi: 10.1016/j.jadohealth.2005.12.025] 10. lucidi f, zelli a, mallia l, et al. the social-cognitive mechanisms regulating adolescents' use of doping substances. j sports sci 2008; 26: 447-456. [doi:10.1080/02640410701579370] 11. mazanov j, petróczi a, bingham j, et al.. towards an empirical model of performance enhancing supplement use: a pilot study among high performance uk athletes. j sci med sport 2008;11:185-190 [doi.org/10.1016/j.jsams.2007.01.003] 12. van der walt v, coopoo y. a survey of the attitudes and knowledge of parents of high school children on the east rand on the usage of nutritional supplements. s afr j sports med 2016; 28: 74-78. [https://doi org/:10.17159/2078516/2016/v28i3a1674] 13. froiland k, koszewski w, hingst j, et al.. nutritional supplement use among college athletes and their sources of information.int j sports nutri exerc metab 2004; 14: 104-120 [ https://doi.org/10.1123/ijsnem.14.1.104] 14. mottram dr. doping control in sport. in: drugs in sport. 4th ed. london: taylor & francis, 2005; 1-31. 15. mueller k, hingst j. the athlete's guide to sports supplements. champaign, ill.: human kinetics. 2013. 16. gradidge p, coopoo y, constantinou d. prevalence of performance-enhancing substance use by johannesburg male adolescents involved in competitive high school sports. arch exerc health dis 2011; 2: 114-119. [doi: 10.5628/aehd.v2i2.102] https://doi.org/10.1038/oby.2000.75 https://doi.org/10.1016/j.jadohealth.2005.12.025 https://doi/ a recent thought-provoking paper compared modern lifestyle to the lifestyle of our ancestors, the hunter-gatherers. 1 there is a distinct contrast to the low levels of physical activity in modern times compared with when our ancestors lived as hunter-gatherers, expending large amounts of energy while they obtained food and water, maintained their shelters and escaped from predators. the genes governing the characteristics required for this lifestyle were passed on for approximately 84 000 generations which spanned this period. this, however, is not a long time from an evolutionary perspective. consider, for example, that the agricultural revolution, during which time food became more readily available, occurred about 350 generations ago, the industrial revolution about seven generations ago and the digital age about two generations ago. 1 each phase of development placed less emphasis on the necessity for superior physical ability for survival and success. for example, hunter-gatherers covered about 6 16 km per day, with daily energy expenditure for physical activity of 800 1 200 kcal – this is 3 5 times more than that of the average modern-day american. despite the physical demands of modern-day lifestyles being less than it was several generations ago, the physiological and metabolic characteristics of humans in 2011 are still wired to deal with the physical demands of the hunter-gatherer era, where the norm was to have a high level of energy expenditure. this manifests as modern-day diseases such as heart disease, obesity, diabetes and stroke – diseases which all have a link to low habitual physical activity. there are other examples of the mismatch between design and action. in the hunter-gatherer era, any stressful situation was of a physical nature where the physiological response was to prepare to either fight or flee from the danger. in modern times, although stress can have emotional or psychological origins, the physiological response prepares us for fighting or fleeing. the consequences manifest as heart disease and hypertension. another example can be found in the truck-driving industry. long-haul truck drivers sit motionless for most of the day, for most of their adult working careers – there is surely no coincidence that truck drivers have an unusually high incidence of haemorrhoids, thought to be a consequence of the poor circulation as a result of inactivity for long periods. our genetic coding has not adapted to this modern-day requirement. the relationship between genes and medical conditions is not new – the ‘thrifty gene’ hypothesis has been around since 1962 when anthropologist james neel suggested that human ancestors were adapted for a feast or famine scenario. as hunter-gatherers they either had periods during which food was readily available or periods during which food was scarce. their metabolism was efficient at storing food as fat to prepare them for the famine. this efficient metabolic mechanism does not work as well in a situation where food is plentiful, resulting in the problem of obesity which is so common in developing countries. probing the genetic aspect in more detail, a study described the results of four khoisan tribal leaders who live as hunter-gatherers in different parts of the kalahari. 2 these four tribal leaders had their entire genomes coded and as a result joined an elite group of 11 humans who have also had their entire genomes sequenced. 3 archbishop desmond tutu and james watson, the scientist who explained the structure of dna, are other famous names in this unique group. this study concluded that, despite being from similar geographical regions, the genetic diversity of the four khoisan was unexpected. 2 the authors concluded that it is most important to include africans in studies on human genetics. firstly the genetic diversity was novel, and secondly africa is the birthplace of humanity. as a consequence it is reasonable to assume that the genetic profile of indigenous africans may have differences compared with examples from other parts of the world. the researchers point out that this may have implications for medical research – most of the decisions linking genes to disease are based on eurocentric genetic databases. a database of indigenous africans may be needed to solve some of the regional medical problems. 3 on a practical level, the response to the problems associated with low levels of physical activity in modern society is gaining momentum through the exercise is medicine tm movement (www. exerciseismedicine.org). the south african sports medicine association has taken up the challenge to promote physical activity as a significant modifier of disease and quality of life and has established a regional chapter. other active organisations such as global advocacy for physical activity, and african physical activity network, both with strong south african networks, are starting to communicate, so the message of promoting physical activity and translating this into action in south africa will be stronger than ever. 1. o’keefe j, vogel r, lavie c, cordain l. achieving hunter-gatherer fitness in the 21st century: back to the future. am j med 2010;123(12):10821086. 2. akst j. african genomes sequenced. the scientist magazine of life sciences. http://classic.the-scientist.com/blog/display/57147/, 2010 (accessed 13 june 2011). 3. schuster sc, et al. complete khoisan and bantu genomes from southern africa. nature 2010;463(7283): 943-947. mike lambert editor-in-chief hunter-gatherer fitness – implications for health editorial 34 sajsm vol 23 no. 2 2011 original research 1 sajsm vol. 30 no. 1 2018 injury and illness profiles during the 2014 south african ironman triathlon l j holtzhausen,1 mbchb, mphil (sports medicine), phd, facsm, c r smit,1 mbchb, m (sports medicine), g joubert,2 ba, msc, k von hagen,3 mbchb, msc (sports medicine) 1 department of sport and exercise medicine, faculty of health sciences, university of the free state, bloemfontein, south africa 2 department of biostatistics, faculty of health sciences, university of the free state, bloemfontein, south africa 3 intercare walmer, kings court mall, corner buffelsfontein and titian roads, port elizabeth, south africa corresponding author: l j holtzhausen (holt.louis@gmail.com) the ironman south africa (imsa) is one of 28 global ironman triathlon races and combines the sports of open water swimming (3.8 km), cycling (180 km) and running (42.2 km). triathletes are exposed to more challenging environmental conditions and physiological demands than athletes participating in most other individual sporting events. the long duration and extreme physical and mental demands of the sport place severe strain on participants. triathletes may consequently present with a variety of medical problems during the competition, including exhaustion and dehydration, muscle cramping, hypothermia, heat stroke and musculoskeletal injuries.[1,2,3] in most triathlon events, the swimming segment is potentially the most dangerous due to complications such as, accidental drowning, hypothermia and cardiac arrest.[3,4] the risk of adverse medical events is influenced by environmental aspects such as, water and air temperature, presence of currents and accidental collisions between athletes.[1] the cycling segment also presents environmentally-driven medical concerns. dehydration and trauma from falling are injuries most frequently reported. ironman distance triathlon injuries and dropouts occur mostly during the cycling and running sections respectively, most likely due to the cumulative physical and mental stress of the previous two segments, but results vary.[1,2] there is a need for ongoing scrutiny of injury and illness profiles of ultra-distance athletes. such data are useful for monitoring long-term changes in the frequency and circumstances of injuries, and assist greatly in the preparation of medical services.[5] the aim of this study was to determine medical history, injury and illness profiles of athletes who received medical attention during the 2014 imsa event, and to investigate the time and place of presentation. methods this was a retrospective, cross-sectional study. the study population consisted of all the competitors who participated in the 2014 imsa event. all athletes who required medical attention (‘patients’) during the event at the main medical tent and all of the medical posts or mobile units along the route were included in this study. spectators and staff who received medical treatment were excluded. the information used in this study was obtained from the standard documentation of medical encounters by personnel on duty at the event. medical and demographical information of all athletes requiring medical attention was documented as standard procedure at all imsa events. clinical diagnoses were made and recorded by clinical staff on duty. diagnoses were made by means of history, clinical examination, including blood pressure, heart rate, core temperature measurement, and special investigations as needed, including blood gases, glucose, urea and electrolyte measurement, urinalysis, spirometry and ecg. the completed documentation was obtained from the race medical director (rmd) and the information captured on a data collection form. for the purposes of this analysis, where a final diagnosis could not be made with the available resources, the main presenting symptoms that were treated were reported. demographic background: there is a need for ongoing scrutiny of injury and illness profiles of ultra-distance athletes. this study aimed to record the medical history, illness and injuries of athletes receiving medical attention during the 2014 ironman south africa (imsa) triathlon, and to investigate the temporal presentation of medical encounters. methods: this was a retrospective, cross-sectional study. all athletes who required medical attention at the main medical tent and all of the medical posts or mobile units along the route were included in this study a total of 2 331 athletes started the race. data included age, gender, time and stage of the race when medical attention was required, pre-race medical history and medication use, illness and injuries treated, special investigations performed, and weather conditions. results: overall, 179 athletes (7.7%) required medical attention. the incidence of medical encounters was 7.8%. a significantly higher percentage of younger participants encountered medical problems (p = 0.04). most patient encounters (80.1%) occurred after the race. the median duration of treatment was 26 minutes. medication was used by 35.1% of patients during the race. the most common medical encounters were exertion-related (71.2%), gastrointestinal (16.4%), dermatological (11.9%), musculoskeletal (9.6%) and cardiorespiratory conditions (2.4%). conclusion: medical encounters occurred more frequently in later stages of the race. most medical conditions were exertionrelated. potential higher risk may be associated with medication use, recent illness, and in younger participants. temporal stacking of medical personnel, planning of resources according to expected conditions, preventative measures for high-risk behaviour, and on-going data collection with comparable methodology are recommended. keywords: triathletes, medical encounters, medication use, treatment, event medical management s afr j sports med 2018;30:1-6. doi: 10.17159/2078-516x/2018/v30i1a1509 mailto:holt.louis@gmail.com http://dx.doi.org/10.17159/2078-516x/2018/v30i1a1509 original research sajsm vol. 30 no. 1 2018 2 information for all athletes was also obtained. weather conditions on race day were provided by the sa weather service. because of incomplete retrospective data obtained from the race medical documentation in a small number of cases, patient numbers from which percentages were obtained vary slightly. the actual numbers used are reflected in the results. all medical staff at the 2014 imsa event were briefed prior to the event on accurate documentation of all medical encounters. in order to prevent inter-observer bias, only one author captured the data obtained from the medical records on the data collection forms. data were analysed by the department of biostatistics, faculty of health sciences, university of the free state (ufs), using sas version 9.3. descriptive statistics, namely, frequencies and percentages (categorical variables) and means, and standard deviations (sd) or percentiles (numerical variables) were calculated. subgroups were compared using fisher’s exact test or chi-squared tests, with level of statistical significance set at 0.05. the study was approved by the ethics committee of the faculty of health sciences, ufs (ecufs 119/2014). permission was obtained from the rmd of the 2014 imsa event. results demographic data a total of 2 331 athletes started the race of which 82.0% (n = 1 911) were male and 18.0% (n = 420) female. during the event, 179 athletes (7.7%) reported to the race medical areas for attention. this represents 76.8 medical events per 1 000 race starters. there was no statistical difference between male and female athletes, with 7.4% (n = 141) of male athletes and 9.1% (n = 38) of female athletes requiring medical attention (p = 0.24). the mean age of the patients was 37.7 years (range 21-63 years; sd 8.4 years). younger athletes between the ages of 18-24 years had the highest percentage requiring medical attention (14.7%), followed by athletes in the 25-29 year age group (12.8%) (table 1). less than 10% of athletes in all other age groups required medical attention (p = 0.04). race information the average wind speed, temperature and humidity levels were calculated for each segment of the race. the measurements for the swim segment were 3 km/h, 17.3°c and 81.5%, for the cycling segment 6.1 km/h, 19.7°c and 84.3%, and for the running segment 7.8 km/h, 20°c and 82.3%, respectively. information regarding the time slots during which the athletes presented is depicted in fig. 1. the 2014 imsa event started at 06:00 and concluded at 24:00, with total possible duration of 18 hours. the highest percentage of athletes (n = 33; 18.4%) presented between 19h00 and 19h59. there was an increase in patient presentation from 16:00 until approximately 23:00, during which time 88 patients (49.2%) attended the medical facilities. the median duration of stay was 26 minutes per patient (range 2-161 minutes). table 2 shows the part of the race during which the athletes presented. most patients (n = 129; 80.1%) presented after completing the race. the second highest number of presentations were during the cycling segmentation (n = 17; 10.6%). pre-race medical history and medication use the use of chronic medication was reported by 19.5% (n = 34) of patients. the most common chronic medications were asthma medications (5.2%) and anti-hypertensives (4.0%). of the 179 patients, 36.2% (n = 63) reported using acute medication in the three days before the race. the most common reported medications were non-steroidal anti-inflammatory medication (nsaids) (n = 22; 12.1%) and analgesics (n = 10; 5.8%). in the 30 days preceding the event, 27.8% (n = 48) of the patients reported suffering from an illness. thirty-six (20.8%) patients reported an upper respiratory tract infection (urti) and five (2.9%) reported gastroenteritis. table 1. biographical variable of age (years) athletes requiring medical attention during the imsa 2014 event age categories yes (n = 174) n (%) no (n = 2 157) n (%) total (n = 2 331) n (%) 18-24 5 (14.7) 29 (85.3) 34 (1.5) 25-29 28 (12.8) 191 (87.1) 219 (9.4) 30-34 36 (8.1) 410 (91.9) 446 (19.1) 35-39 33 (7.5) 410 (92.6) 443 (19.0) 40-44 38 (7.0) 503 (93.0) 541 (23.2) 45-49 16 (4.9) 308 (95.1) 324 (13.9) 50-54 12 (5.9) 191 (94.1) 203 (8.7) 55-59 4 (4.6) 83 (95.4) 87 (3.7) 60-64 2 (7.7) 24 (92.3) 26 (1.1) 65+ 0 (0) 8 (100.0) 8 (0.3) n = total number of athletes, % = percentage of total athletes 06 h 00 -6 h 59 07 h 00 -7 h 59 08 h 00 -8 h 59 09 h 00 -9 h 59 10 h 00 -1 0h 59 11 h 00 -1 1h 59 12 h 00 -1 2h 59 13 h 00 -1 3h 59 14 h 00 -1 4h 59 15 h 00 -1 5h 59 16 h 00 -1 6h 59 17 h 00 -1 7h 59 18 h 00 -1 8h 59 19 h 00 -1 9h 59 20 h 00 -2 0h 59 21 h 00 -2 1h 59 22 h 00 -2 2h 59 23 h 00 -2 3h 59 24 h 00 -2 4h 59 0 5 10 15 20 time % a th le te s fig 1. distribution of medical contacts per time of day 0.6 0.6 1.1 0.0 0.0 1.7 1.1 2.2 1.7 1.1 7.8 5.6 18.4 10.6 8.4 14.5 10.6 12.3 1.7 original research 3 sajsm vol. 30 no. 1 2018 medication use during the imsa more than a third of patients (35.1%, n = 61) reported using medication during the race (table 3). the most common medications were nsaids (16.1%) and analgesics (14.4%). diagnoses, symptoms and signs medical complaints encountered by medical staff at the imsa were categorised in clusters, as presented in table 4. the most common group of conditions was exertion-related (n = 137; 64.6% of diagnoses made): 34.0% cases of exercise-associated collapse (eac)/hypotension (n = 72), 9.4% dehydration (n = 20), 5.2% exhaustion (n = 11), 5.2% hypothermia (n = 11) and 5.2% exercise-associated muscle cramps (eamc) (n = 11). six cases of hyponatraemia were diagnosed (2.8%). hypoglycaemia (n = 5) accounted for 2.4% of cases and hyperthermia (n = 1) accounted for <1%. the second most prevalent cluster of diagnoses was related to the gastrointestinal system (n = 29; 13.7%). sixteen cases of nausea with or without vomiting were recorded (7.6%), followed by epigastric pain and diarrhoea (n = 6; 2.8% each), and one case of heartburn (<1%). the dermatological cluster contributed 9.9% (n = 21), mostly skin abrasions (‘road rash’) (n = 10; 4.7%), followed by blisters (n = 7; 3.3%), two bee stings (<1%) and one case of erythema and sunburn (<1%) each. seventeen musculoskeletal diagnoses were recorded (8.0%): 10 (4.7%) overuse injuries (low back pain, achilles tendon pain, peroneal tendon pain, cervical muscle spasm, patellofemoral pain, and iliotibial band friction syndrome), and seven (3.3%) acute traumatic injuries (muscle sprains, ankle sprains, and shoulder dislocation). five (2.4%) cardiorespiratory diagnoses were recorded, all potentially serious. one diagnosis of pulmonary embolism, atrial fibrillation, asthma, bronchospasm and sore throat with coughing each, were made. special investigations blood glucose testing was performed in 85.8% (n = 152) of the patients, while blood gas and urea and electrolytes were tested in 29.9% of the patients, respectively (n = 53). electrocardiograms (ecgs) were done in three (1.7%) patients. discussion despite the increasing popularity of ironman distance triathlons, there is a lack of data on injury and illness profiles in these events.[5] imsa and other events rely on historical data collected from previous events to plan the medical facilities and services for future events. this requires data on the predicted number, nature and severity of the casualties.[2,5] incidence of medical encounters of the 2 331 athletes competing, 7.7% required medical attention. this is lower than the 10.1% documented for the 2013 imsa event.[6] injury and illness rates are recorded and reported with inconsistent methodology, making results difficult to compare. there are many external event-related variables which influence medical encounter data, including environmental factors, distances, age and the level of competence of competitors.[1,2,7] similar studies noted a treatment presentation rate of between 2% and 37.7%.[2,5] medical staff can therefore estimate to manage approximately 30% of race starters during the course of the event, but can amend the estimates according to recent statistics and environmental variables on race day. timing of medical encounters the majority of medical encounters (80.1%) occurred after the race, while nearly half occurred in the last eight hours. similar trends have been recorded in other ironman events, with peak times of medical encounters coinciding with that of finishing times.[2,5] a positive correlation between the time of arrival and treatment duration has been recorded previously, meaning patients arriving later are expected to require longer treatment times.[5] little has been published on the numbers and qualifications of medical personnel at ironman events. a medical support team comprising a medical director, one additional physician per 200 athletes, one nurse per 100 athletes and additional paramedical and ambulance staff are recommended for a standard triathlon.[3] the onsite medical team for the halfand ironman distance triathlon with 1 923 participants in rural canada consisted of 120 members, of which key personnel were five physicians, 11 nurses and 36 paramedics.[2] rimmer and coniglione[5] concluded that medical care at amateur triathlon events should be planned according to the temporal flow of injuries throughout the event, and that medical support be increased by 20% to three doctors, nine nurses and support staff per 100 participants in the latter stages of triathlons. in this study, the peak patient intake was 33 patients per hour, and the average intake for the last eight hours was 20 patients per hour. the imsa medical plan provides for a staffing schedule according to expected patient flow, allocating one doctor and two nurses per four patients. provision is made for 37 beds of which three are intensive care table 2. stages of the race completed by the athletes requiring medical attention during the 2014 imsa event (n = 161) stage n (%) swim 2 (1.2) stopped at first transition 0 (0) stopped during cycling 17 (10.6) stopped at second transition 4 (2.5) stopped during marathon 9 (5.6) completed the race 129 (80.1) n = total number of athletes, % = percentage of total athletes table 3. medication used during the 2014 imsa by athletes requiring medical attention (n = 61) medication n (%) non-steroidal anti-inflammatory (nsaids) 28 (16.1) analgesics 25 (14.4) anti-diarrheal medication 7 (4.0) muscle relaxants 7 (4.0) anti-nausea/vertigo/abdominal cramp tablets 4 (2.3) crampease™ (johannesburg, south africa) 3 (1.7) antacids 3 (1.7) magnesium tablets 2 (1.2) salt tablets 2 (1.2) n = total number of athletes, % = percentage of total athletes original research sajsm vol. 30 no. 1 2018 4 and two are equipped for surgical cases.[8] using this formula, the maximum bed occupation in the imsa medical facility has never exceeded 30 (dr. konrad von hagen, imsa medical director, personal communication). mobile or secondary units should be available along the cycling, running and changeover areas, and dedicated staff and equipment should be readily available on or near the water for swift management of emergencies from the swim event. environmental factors the degree of environmental stress is a health risk factor in ultra-endurance events.[2,3] one contributing factor to the relatively low incidence of medical encounters in this study is the mild weather conditions during the race. the average ambient temperature, wind strength and humidity on race day were well within the norms of the environmental recommendations for triathlons.[1,3] gender at both the 2013 and 2014 imsa events, male patients comprised 79% and female patients 21% of the total number of athletes treated.[6] no statistical difference between female and male medical encounter rates were found in this study (p = 0.24). similar results were recorded in the two oceans ultramarathon between 2008 and 2011.[7] other gender-related risk data are ambiguous.[2,9] further studies are needed to identify possible gender-specific modifiable risk factors in ultradistance athletes. age and experience athletes between the ages of 18-24 years had a significantly higher incidence of medical encounters than older athletes. table 4. diagnoses, symptoms or signs of athletes requiring medical attention diagnosis cluster diagnosis n* % of 177 patients % of 212 diagnoses metabolic/exertion-related 126 (71.2) 137 (64.6) exercise associated collapse (eac)/hypotension 72 40.7 34.0 dehydration 20 11.3 9.4 exhaustion 11 6.2 5.2 exercise-associated muscle cramps (eamc) 11 6.2 5.2 hypothermia 11 6.2 5.2 hyponatremia 6 3.4 2.8 hypoglycaemia 5 2.8 2.4 hyperthermia 1 0.6 0.5 gastrointestinal 29 (16.4) 29 (13.7) nausea 16 9.1 7.6 epigastric pain 6 3.4 2.8 diarrhoea 6 3.4 2.8 heartburn 1 0.6 0.5 dermatological 21 (11.9) 21 (9.9) skin abrasions (‘road rash’) 10 5.6 4.7 blisters 7 4.0 3.3 bee sting 2 1.1 0.9 erythema 1 0.6 0.5 sunburn 1 0.6 0.5 musculoskeletal 17 (9.6) 17 (8.0) lower back pain 4 2.3 1.9 muscle strains 3 1.7 1.4 ankle sprains 3 1.7 1.4 achilles tendon pain 2 1.1 0.9 peroneal tendon pain 1 0.6 0.5 cervical muscle spasm 1 0.6 0.5 patellofemoral pain 1 0.6 0.5 shoulder dislocation 1 0.6 0.5 iliotibial band friction syndrome 1 0.6 0.5 cardiorespiratory 5 (2.4) 5 (2.4) pulmonary embolism† 1 0.6 0.5 arial fibrillation 1 0.6 0.5 asthma 1 0.6 0.5 bronchospasm 1 0.6 0.5 sore throat and coughing 1 0.6 0.5 neurological 2 (1.1) 2 (0.9) concussion 2 1.1 0.9 unclassified 1 (0.6) 1 (0.5) urine discolouration 1 0.6 0.5 n = total number of athletes, *a patient can have more than one diagnosis in a diagnosis cluster. †diagnosis made on recent history of pulmonary embolism, chest pain, haemoptysis and ecg changes. original research 5 sajsm vol. 30 no. 1 2018 even though younger age is suggestive of less experience, it does not necessarily reflect the association. however, these results correlate with the finding that less running experience is a risk factor for medical complications in ultra-marathon events.[9,10] this finding may be explained by self-selection of older, more experienced athletes with less career injuries, that older athletes possibly focus more on participation than winning, or address injuries earlier, before they escalate.[9] analysis of possible preventable medical complications in less experienced athletes should be pursued further in order to introduce prevention strategies. rule adaptations have been made, including dedicated novice starting waves to minimise psychological stress and physical risk at the start of these events.[1] pre-race medical history and medication use chronic medication use was reported by 19.5% of patients, and 27.8% suffered an illness in the 30 days before the competition. pre-existing acute and chronic medical conditions may pose an increased risk for medical complications during endurance exercise. in this retrospective study, it is unknown if there is a difference in the prevalence of pre-race acute or chronic medical conditions between athletes who did not need medical attention and those who did. therefore no conclusions can be drawn. use of acute medication in the three days before the competition was reported by 36.2% of patients, and during the race by 35.1%. the prevalence of medication use among all participants is not known and relative risk cannot be calculated. however, the most commonly used medication in the three days preceding the race (12.1%) and during the race (16.1%) was nsaids. these figures are much lower than the 30.0% of athletes using nsaids during the 2004 new zealand ironman.[11] in the 2008 brazil ironman, 59.9% of a cohort of participants reported using nsaids in the previous three months; of these, 25.5%, 17.9% and 47.4% took nsaids the day before, immediately before and during the race, respectively.[12] underreporting may have occurred in this study because of the athletes’ apprehension to disclose risky behaviour. a high rate of non-prescribed nsaid use and limited awareness of the risks thereof have been reported in ironman athletes.[12] medical conditions treated during the 2014 imsa the majority of patients (71.2%) treated during the 2014 imsa suffered from exertion-related conditions which included eac, dehydration and exhaustion. in the 2010 redman triathlon, oklahoma, usa, dehydration accounted for 50.7% of medical encounters, while dehydration and exhaustion contributed 72% of medical encounters in the 1999 hawaii ironman event.[5] the incidence of eamc (5.2%) was much lower than the 36.1% in the 2010 redman triathlon[5] and the 11% in the two oceans marathon from 2008-2011,[10] but similar to the 6% recorded in the hawaii ironman.[2] it seems that eamc is more prevalent in shorter, faster events.[13,14] hypothermia (5.2%) was more prevalent than hyperthermia. low numbers of temperature regulatory dysfunction have been reported in ultra-distance events.[2,10] nevertheless, proper management protocols for these potentially dangerous conditions should be in place.[3] likewise, hyponatremia (2.8%) and hypoglycaemia (2.4%) were uncommon, but should be managed optimally. gastrointestinal system complaints were the second most common group of conditions recorded. non-specific diagnoses of nausea were made in 7.6% of patients. it can be challenging to make specific diagnoses of a general symptom, such as nausea, in a pre-hospital setting. serious gastrointestinal conditions, such as gastrointestinal bleeding and ischaemia, have been recorded in ultra-endurance events.[1,2] prompt referral should be done in persistent cases, or where systemic symptoms indicate more serious disease. the majority of dermatological (9.9%) and musculoskeletal (8.0%) conditions treated during the 2014 imsa were minor, as reported previously.[9,10] skin conditions consisted mostly of abrasions and blisters. only one case of sunburn was reported. this may represent underreporting as athletes may have opted not to seek treatment for sunburn. ultraviolet radiation was measured in three athletes in the 1999 hawaii ironman. mean ultraviolet radiation exposure during the competition was 8.3 times the minimal erythema doses, and greatly in excess of the international radiation protection agency guidelines, despite using sun protection factor 25+ sunscreen.[15] copious amounts of sunscreen were made available to all participants during the imsa 2014. the number of cardiorespiratory diagnoses was low (2.4%), but included potentially life-threatening conditions such as pulmonary emboli and atrial fibrillation. such conditions should not be misdiagnosed for the much more common exertion-related diagnoses that can present in a similar way. serious cardiorespiratory complications have been recorded in ultra-endurance events,[5,10] and medical facilities should be equipped to manage such emergencies. special investigations the availability of basic special investigations and ecg were essential in the diagnosis and management of a high percentage of patients during imsa 2014. these aids are potentially lifesaving and should be standard equipment available in ultraendurance events. conclusion in this study, accurate reporting of all patient encounters during the 2014 imsa was achieved. an accurate diagnostic profile, temporal presentation and consideration of factors that could potentially influence the profile of medical encounters allowed these authors to present an approach to planning of medical resources for future imsa competitions. in accordance with previous studies, exertion-related medical conditions have been predominant in imsa events. potential preventative measures have been identified, including education on potentially harmful medication use during the race, recent illness, and prevention of medical complications in younger participants. longitudinal prospective recording of medical encounters and associated factors, with standardised diagnostic criteria and terminology is recommended for ultra-endurance events to accumulate accurate evidence on which to plan original research sajsm vol. 30 no. 1 2018 6 prevention and medical services. limitations limitations are, however, that data on all participants could not be obtained for comparison and risk calculation. furthermore, the specific nomenclature of conditions and standardisations of diagnoses could not be done for a more accurate comparison with the literature, as diagnoses were obtained retrospectively from the clinical notes of medical staff on duty at the event. the relative lack of recent studies on the topic necessitated the use of older comparative literature. the severity of medical conditions was not recorded. acknowledgements: ms t mulder, medical editor, school of medicine, ufs, for technical and editorial preparation of the manuscript. conflict of interest and source of funding: none references 1. dallam gm, jonas s, miller tk. medical considerations in triathlon competition: recommendations for triathlon organisers, competitors and coaches. sports med 2005;35(2):143-161. [doi:. 10.2165/00007256-20053502000004] 2. turris sa, lund a, bowles rr, et al. patient presentations and medical logistics at full and half ironman distance triathlons. curr sports med rep 2017;16(3):137-143. [doi:10.1249/jsr.0000000000000367] 3. the triathlon canada medical committee. triathlon medical manual. canada: triathlon canada medical committee, july 2000. http://www.triathlon.mb.ca/admin/images/seasons/sancti on_triathloncanada_medicalmanual.pdf (accessed 26 september 2016). 4. laird rh, johnson d. the medical perspective of the kona ironman triathlon. sports med arthrosc rev 2012;20(4):239. [doi: 10.1097/jsa.0b013e3182736e8e] 5. rimmer t, coniglione t. a temporal model for nonelite triathlon race injuries. clin j sport med 2012;22(3):249-253. [doi: 10.1097/jsm.0b013e318249945b] 6. ironman south africa. statistics of the 2013 event. internal document. ironman south africa, 2013. 7. schwabe k, schwellnus mp, derman w, et al. less experience and running pace are potential risk factors for medical complications during a 56 km road running race: a prospective study in 26 354 race starters--safer study ii. br j sports med 2014;48(11):905-911. [doi: 10.1136/bjsports2014093471] 8. standard bank ironman african championship. medical plan – 29 march 2015 (updated 5 march 2015). internal document. ironman south africa, 2016. 9. krabak bj, waite b, schiff ma. study of injury and illness rates in multiday ultramarathon runners. med sci sports exerc 2011;43(12):2314-2320. [doi: 10.1249/mss.0b013e318221bfe3] 10. schwabe k, schwellnus m, derman w, et al. medical complications and deaths in 21 and 56 km road race runners: a 4-year prospective study in 65 865 runners--safer study i. br j sports med 2014;48(11):912-918. [doi: 10.1136/bjsports 2014-093470] 11. wharam pc, speedy db, noakes td, et al. nsaid use increases the risk of developing hyponatremia during an ironman triathlon. med sci sports exerc 2006;38(4):618-622. [doi: 10.1249/01.mss.0000210209.40694.09] 12. gorski t, cadore el, pinto ss, et al. use of nsaids in triathletes: prevalence, level of awareness and reasons for use. br j sports med 2011;45(2):85-90. [doi: 10.1136/bjsm.2009.062166] 13. schwellnus mp, drew n, collins m. increased running speed and previous cramps rather than dehydration or serum sodium changes predict exercise-associated muscle cramping: a prospective cohort study in 210 ironman triathletes. br j sports med 2011;45(8):650-656. [doi:10.1136/bjsm.2010.078535] 14. schwellnus mp, allie s, derman w, et al. increased running speed and pre-race muscle damage as risk factors for exercise-associated muscle cramps in a 56 km ultramarathon: a prospective cohort study. br j sports med 2011;45(14):1132-1136. [doi:10.1136/bjsm.2010.082677] 15. moehrle m. ultraviolet exposure in the ironman triathlon. med sci sports exerc 2001;33(8):1385-1386. [doi: 10.1097/00005768-200108000-00021] km_c227-20180511120516 original research 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license evaluation of match-running distances covered by soccer players during the uefa euro 2016 a kubayi, dphil (sport science) department of sport, rehabilitation and dental sciences, faculty of science, tshwane university of technology, pretoria, south africa corresponding author: a kubayi (kubayina@tut.ac.za) soccer is the world’s most popular sport played on all continents.[1–3] its popularity coincides with the need for research into the match performance analysis in soccer. in recent years, technological advances have included the introduction of increasingly sophisticated motion analysis systems now being used in elite soccer.[4] the use of these advanced approaches has made new methods more feasible and accessible, allowing for a greater volume of data to be collected in less time.[5] to obtain physical performance indicators among soccer players, a variety of methods, such as visual evaluation, the global positioning system, and the semi-automated multi-camera tracking system have all been recommended in the literature.[6] however, the most commonly used method is the semiautomated multi-camera tracking system[7] which provides more precise information about the technical and physical performance indicators of the players during soccer matches. the validity of the semi-automated multi-camera tracking system has been demonstrated in several previous studies.[8,9] more specifically, the semi-automated multi-camera tracking system describes the technical actions of players and allows the monitoring of the total running distances covered at various intensities.[10] this system, which is based on numerous calibrated cameras, allows the monitoring of all players on the pitch during the match, both with or without the ball. consequently, coaches and scientists can record the players’ technical, tactical and physical data simultaneously.[11] for example, previous research[12] has reported that soccer players generally cover a total distance of between 9 and 14 km during a match, with much of the game played at a low intensity, such as standing, walking and jogging. specifically, bradley et al.[13] found that wide and central midfielders (wms; cms) covered longer distances than wide defenders (wds), central defenders (cds), and attackers (ats). likewise, wds, cms, and ats covered greater distances in high-intensity running compared to cds.[13] although extensive literature has analysed the movement patterns among professional players in domestic leagues,[4,5,11] there is limited information on the uefa european championship. therefore, a more detailed analysis of the movements displayed by soccer players in such a competition may provide a better understanding of the physical demands of the game.[14] thus the purpose of this study was to analyse the match-running distances covered by soccer players during the uefa euro 2016. methods match data and participants a total of 228 soccer players (with the exception of the goalkeepers), who played 15 full matches during the uefa euro 2016 tournament were observed and their movements analysed. the outfield players were grouped according to one of five playing positions as follows: cds (n=58), wds (n=45), cms (n=53), wms (n=38), and ats (n=34). to ensure confidentiality, match-running data were analysed without any reference to specific players and/or teams. permission to conduct the study was granted by the instat company, and the study’s protocol was approved by the faculty of science research ethics committee of the tshwane university of technology, pretoria, south africa. data collection the match-running distance of players was monitored using the multiple-camera tracking system (instat). physical data were captured with video cameras installed in pairs on each of the two main stands of a soccer stadium. the portable instat fitness system set includes two video cameras positioned on tripods on one of the stands, with each of the two cameras background: despite a substantial body of literature on match-running distances covered by soccer players in domestic leagues, there appears to be limited information on the union of european football associations (uefa) euro competitions. objective: the aim of this study was to analyse the matchrunning distances covered by soccer players during the uefa euro 2016. methods: a multiple-camera tracking system (instat ltd) was used to analyse 228 observations of soccer players who played 15 full matches during the tournament. the outfield players were categorised according to the following playing positions: central defenders (cds), n=58; wide defenders (wds), n=45; central midfielders (cms), n=53, wide midfielders (wms), n=38; and attackers (ats), n=34. data were reported as means with 95% confidence intervals (ci). a one-way analysis of variance (anova) was undertaken to examine the significant differences among players based on playing positions. results: the results indicated that the overall total distance covered by players was 10 350 m, ranging from 8 446 m to 12 982 m. ats covered the longest distance in high-speed running (872 m; 95% ci = 813–931), while cds covered the shortest distance (542 m; 95% ci = 503–581). a statistically significant difference was observed in high-speed running among players (f (4 223) = 36.92, p=0.001). conclusion: the findings of this study provide soccer scientists and coaches with important information to design and implement training sessions in order to elucidate the physical demands of players in view of successful team performance. keywords: movement patterns, high-speed running, training s afr j sports med 2019;31:1-4. doi: 10.17159/2078-516x/2019/v31i1a6127 http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6127 https://orcid.org/0000-0002-8370-3056 original research sajsm vol. 31 no. 1 2019 2 covering half of the field. previous research has reported the accuracy of the instat tracking system in assessing physical performance.[9] the physical performance movements of the soccer players were classified as follows: walking (0–7 km/h), jogging (7.1–14.5 km/h), running (14.6–20 km/h), high-speed running (20.1–25 km/h) and sprinting (>25 km/h). statistical analysis data were reported as means with 95% confidence intervals (ci). a one-way analysis of variance (anova) was used to assess the significant differences among players according to playing positions (i.e., cd, wd, cm, wm, and at). where the f-ratio was significant (p≤0.05), the tukey hsd post-hoc test was undertaken for further analysis. data were analysed by means of the statistical package for the social sciences (spss), version 25.0 (spss inc., chicago, il, usa). results table 1 presents distances covered during entire matches according to players’ field positions. it was found that an average total distance covered during the matches played was 10 350 m, ranging from 8 446 m to 12 982 m. specifically, cms (10 981 m; 95% ci = 10 787–11 174), ats (10 532 m; 95% ci = 10 313–10 751), and wms (10 534 m; 95% ci = 10 374–10 693) significantly covered a greater total distance compared to wds (10 274 m; 95% ci = 10 097–10 451) and cds (9 423 m; 95% ci = 9 300–9 546). the results indicated that cds covered longer walking distances (3 634 m; 95% ci = 3 559–3 710) than players in other outfield positions. there was a statistically significant difference in walking distances for the groups of players (f (4 223) = 8.52, p=0.001). post-hoc comparisons using the tukey hsd post-hoc test showed that the walking distance for cds was significantly (p<0.05) different from that of cms (3296 m; 95% ci = 3 208–3 383). wds (3 493 m; 95% ci = 3 394–3 592), wms (3 520 m; 95% ci = 3 426–3 614), and ats (3532 m; 95% ci = 3 414–3 651) did not differ significantly from either cds or cms. with regard to high-intensity running, ats covered the longest distance in high-speed running (872 m; 95% ci = 813– 931), while cds covered the shortest distance (542 m; 95% ci = 503–581). a statistically significant difference was observed in table 1. average match-running distances covered during uefa euro 2016 95% ci n mean lower bound upper bound p-value total distance (m) 0.001* cd 58 9423 9300 9546 wd 45 10274 10097 10451 cm 53 10981 10787 11174 wm 38 10534 10374 10693 at 34 10532 10313 10751 walking distance (m) 0.001* cd 58 3634a 3559 3710 wd 45 3493 3394 3592 cm 53 3296 3208 3383 wm 38 3520 3426 3614 at 34 3532 3414 3651 jogging distance (m) 0.001* cd 58 3882 3782 3983 wd 45 4159 3998 4320 cm 53 4717 4585 4850 wm 38 4196 4035 4358 at 34 4274 4057 4491 running distance (m) 0.001* cd 58 1285 1202 1369 wd 45 1627 1506 1748 cm 53 2000 1863 2136 wm 38 1780 1678 1882 at 34 1672 1561 1782 high-speed running (m) 0.001* cd 58 542 503 581 wd 45 799 751 848 cm 53 857 801 914 wm 38 856 813 900 at 34 872b 813 931 sprinting distance (m) 0.001* cd 58 80 70 91 wd 45 195 171 220 cm 53 112 95 130 wm 38 183 157 208 at 34 186 159 213 * statistically significant at p<0.05; asignificantly different from cm, p< 0.05; bsignificantly different from cd, p<0.05. cd, central defender; wd, wide defender; cm, central midfielder; wm, wide midfielder; at, attacker; n, number of participants; ci, confidence interval original research 3 sajsm vol. 31 no. 1 2019 high-speed running between players (f (4 223) = 36.92, p=0.001). the tukey hsd post-hoc analyses indicated that the high-speed running mean score for ats was significantly (p<0.05) different from that of cds. however, the high-speed running for ats and cds did not differ significantly from those of wds (799 m; 95% ci = 751–848), cms (857 m; 95% ci = 801–914), and wms (856 m; 95% ci = 813–900). discussion the results of this study indicated that the average total distance covered by players was 10 350 m throughout the matches analysed. these findings are slightly lower than those of di salvo, et al.,[14] who found that 300 players in the spanish premier league (la liga) and uefa champions league matches covered an average of 11 393 m. the discrepancy between the present findings and those of previous studies probably demonstrates that in modern soccer it is not about how much distance a player covers but knowing where to go at the right time and how to use space efficiently during a match. when the data were analysed according to playing position, midfielders covered greater distances compared to defenders and forwards. this finding could be explained by the fact that midfielders play an important role as a link between defenders and attackers [14] which requires them to shuttle between the attack and defence. previous studies have provided empirical evidence showing that midfield players had higher vo2max values than fullbacks and forwards [14], thus emphasising their indefatigable role associated with long-distance coverage during a match. another important finding in this study was that wds covered more distance overall than their cd counterparts. a plausible reason for this result could be that in modern soccer wds are encouraged to advance to the final third of the field in order to execute crosses into the opposition goal area. this notion is supported by the research of di salvo, et al. [15] who indicated that fullbacks are required to operate in both attacking and defensive contexts in modern match tactics. the finding in which cms covered greater total distances than other players (i.e. cds, wds, wms, and ats) is noteworthy. although it was not ascertained in the current study, the tactical duties of cms could be different from those of other playing positions. the current observations may suggest that cms are subject to greater overall exertion requiring higher fitness levels. the longer distances covered by cms may be associated with team formations and/or playing styles employed by european teams. [5,10,15] with regard to distances covered by players at different work intensities, cds covered greater total distances in lowintensity activities, such as walking. it has been established that cds spend most of time during the game engaged in lowintensity activities without the ball, probably as a result of their involvement being limited to defensive actions. [15] the results also showed that ats covered greater distances of high-speed running compared to players in other positions. the modern approach of attacking players applying higher pressure on the opposition by becoming the first defensive line may also contribute to this finding. the ability to accelerate and reach maximal speeds quickly is an important component of gamedeciding situations in soccer. [13] a requirement for such movement patterns by attacking players in this study can be attributed to the need to complete fast movements away from defending players to create space or capitalise on goal-scoring opportunities. [15] although this study provided novel information on the distances covered by european players, a few limitations should be taken into account. first, due to the various categorisations and technologies employed, caution is necessary in the interpretation of the present findings and comparing them with those reported in the literature. [14] second, the analysis of a small number of matches during this competition also limits the generalisation of the current findings. therefore, future studies involving larger samples of european tournaments, especially uefa euro championships, are needed to clarify the findings of the present study. conclusion the current findings showed that midfielders covered greater total distances than defenders and forwards. while cds spent most time during the game-walking and jogging, ats covered greater distances in high-intensity activities, such as highspeed running, compared to other positions. the results could provide valuable information for soccer scientists and coaches in planning and implementing position-specific training programmes, thereby maximising team performance. references 1. bangsbo j. the physiology of soccer: with special reference to intense intermittent exercise. acta physiol scand suppl 1994; 619: 1–155. [pmid: 8059610] 2. reilly t. energetics of high-intensity exercise (soccer) with particular reference to fatigue. j sports sci 1997; 15(3): 257– 263. [doi: 10.1080/026404197367263] 3. kubayi na, coopoo y, morris-eyton hf. job-related barriers encountered by football coaches in gauteng province of south africa. african journal of physical health education recreation and dance 2015; 21 supplement 1: 160-166. 4. carling c, bloomfield j, nelsen l, et al. the role of motion analysis in elite soccer: contemporary performance measurement techniques and work rate data. sports med 2008; 38(10): 839–862. [doi: 10.2165/00007256-20083810000004] 5. hewitt a. performance analysis in soccer: applications of player tracking technology. canberra: university of canberra 2016:188. 6. toki s, sakurai s. quantitative match analysis of soccer games with two dimensional dlt procedures. in: proceedings of xxth congress of the international society of biomechanics (isb) and the 29th annual meeting of the american society of biomechanics held in cleveland, ohio, usa. 2005. 7. bangsbo j, nørregaard l, thorsø f. activity profile of competition soccer. can j sport sci 1991; 16(2): 110-116. [pmid: 647856] 8. di salvo v, collins a, mcneill b, et al. validation of prozone®: a new video-based performance analysis system. int j perform anal sport 2016; 6(2): 108–119. [doi: 10.1080/24748668.2006.11868359] https://doi.org/10.1080/24748668.2006.11868359 https://doi.org/10.1080/24748668.2006.11868359 original research sajsm vol. 31 no. 1 2019 4 9. dmitriy a, mike v, ilya v, et al. validation and precision analysis of instat fitness system. instat 2013: 1–14. 10. dellal a. analysis of the soccer player's activity and of its consequences in the training: special reference to the high intensity intermittent exercises and the small-sided games. university of strasbourg, france, 2008. 11. dellal a, wong dp, moalla w, et al. physical and technical activity of soccer players in the french first league–with special reference to playing position. int sportmed j 2010; 11(2): 278-290. 12. bangsbo j, michalsik lb. assessment of the physiological capacity of elite soccer players. in: spinks w, reilly t, murphy a, eds. science and football iv. london: routledge, 2002: 53– 62. 13. bradley ps, di mascio m, peart d, et al. high-intensity activity profiles of elite soccer players at different performance levels. j strength cond res 2010; 24(9): 2343–2351. [doi:. 10.1519/jsc.0b013e3181aeb1b3] 14. castagna c, d’ottavio s, abt g. activity profile of young soccer players during actual match play. j strength cond res 2003; 17(4): 775–780. [pmid: 14636107] 15. di salvo v, gregson w, atkinson g, et al. analysis of high intensity activity in premier league soccer. int j sports med 2009; 30(3): 205–212. [doi:10.1055/s-0028-1105950] https://doi.org/10.1519/jsc.0b013e3181aeb1b3 https://doi.org/10.1519/jsc.0b013e3181aeb1b3 https://doi.org/10.1055/s-0028-1105950 100 sajsm vol 19 no.3 2007 to the editor: we would like to comment on the review article by shuttleworth-edwards et al. 'ethically we can no longer sit on the fence – a neuropsychological perspective on the cerebrally hazardous contact sports', published in the july edition of your journal. overall, this article is well researched and written. however, as well as highlighting a number of important observations made in this article, we would like to emphasise the progress that has been made in developing a communitybased return-to-play concussion programme in south africa, thus illustrating that a high level of care can be sourced for patients with concussion wishing to return safely to collision and contact sports. 1. it must be noted that computerised and detailed neurocognitive assessment has no role to play in the prevention of head injury in sport. athletes participating in contact or collision sports are at risk of head injury and the role of mouthguards and headgear is controversial in head injury prevention. neurocognitive assessment does, however, form a component of the return-to-play management of the injured patient. 2. due to a paucity of clinical signs, concussion management and return to play must focus on the cognitive, emotional and behavioural effects of the injury, emphasising again the significant individual variation to this injury. it is also well illustrated how gender differences too are an important consideration, in addition to underlying genetic factors. we would agree with the authors that attributing the social ills of society to mild traumatic brain injury on a cause and effect basis would not be reasonable. 3. the cognitive reserve theory could be a reasonable way of explaining the individual variant in recovery time after injury. 4. we have refined our clinical approach, based on research and our experience in managing this injury that encompasses individual differences in response to concussion. by focussing on serial symptom analyses, clinical evaluations, neurocognitive testing – both computerised screening and detailed clinical assessments – and then finally an exercise challenge, we believe we would be in the best position to support a decision for the patient to return to sport. the third component of exercise challenge has been very important and provides support for the ‘hypoxic theory’ as detailed by ewing et al. 1 the proposal of informed consent is an excellent one and should be incorporated into any sports education programme and certainly into a return-to-play concussion programme. 5. finally, and most importantly, we wish to illustrate that, as sports physicians who come into contact with mild traumatic brain injury on a weekly and often daily basis, we believe that we are incorporating the latest in international clinical consensus 5-7 together with computerised neurocognitive assessments and individualised returnto-play guidelines in a cost-effective, pragmatic model. in the last 3 years, we have developed a community-based concussion programme, incorporating satellite return-toplay concussion centres, under the banner of the pharos schools concussion programme and sports concussion south africa. 2-4 the programme has a number of equally important foci: • education – this we believe to be key; if the sporting public are aware of the significance of concussion and its potential consequences, we believe the risks to be significantly reduced; to this end, the website www.sportsconcussion. co.za has become the central reference tool aiming at educating the public and medical fraternity alike; in addition we have a concerted programme of lectures to schools and clubs aimed at educating pupils, parents and coaches; a campaign to utilise various media including the press, radio and television is also launched annually at the beginning of the schools’ rugby season; at this stage of the season we would also introduce the concept of computerised neuropsychological testing and stress the significance of obtaining baseline data. • acute management – identifying a concussed player, removing them from the field of play and conducting an initial analysis are important first steps; the pharos programme incorporates this by distributing modified versions of the sports concussion assessment tool (scat) to participating schools; the helpline 084-brain24 launched in conjunction with an emergency service call centre advises as to where to obtain medical assistance and the importance of clinical follow-up. • serial clinical assessment – once a case of concussion has been identified, this is an essential step in determining return to play; players undergo a thorough symptom analysis and trends in symptom resolution are tracked; a neurological assessment including verbal cognitive and balance tests is conducted; finally, if appropriate, computerised neuropsychological tests are conducted and compared with baseline or age-appropriate norms; we concur with the view of the american college of sports medicine that computerised neuropsychological testing is desirable in concussion management rather than essential; 7 moreover, contrary to shuttleworth-edwards and whitefields’ assertion that ‘for best practice in the implementation of return-to-play … decisions… registered psychologists are called for…’, we believe this to be impractical, both due to the scarcity and inaccessibility of such resources and the fact that computerised test batteries are designed for team physicians to implement and integrate into their management protocol of a concussed player. 8 ethically we can no longer sit on the fence? letters to the editor pg100-104.indd 100 10/3/07 3:30:21 pm 100 sajsm vol 19 no.3 2007 sajsm vol 19 no.3 2007 101 • return-to-play – this is conducted in a progressive fashion using graded exercise stress to confirm complete resolution of pathology before full sports participation; again the progress will be individualised and poor prognostic indicators such as previous concussions and co-morbid pathology taken into account. in summary, we acknowledge the impetus that computerised neuropsychological testing has given to sports concussion management and research. realistically and practically though, this can only form one part of a clinically orientated serial assessment of the concussed athlete that takes cognisance of both those that have access to this facility and the many (particularly in south africa) that don’t. as sports physicians we see ourselves as foot soldiers in the educational drive and clinical facilitation process of managing mild traumatic brain injury in sport. we are determined to drive a nationally focussed programme of international calibre. the last thing we will do is sit on the fence. ryan kohler jon patricios sports concussion south africa and pharos schools concussion programme: cape town and johannesburg 1. ewing r, mccarthy d, gronwall d, wrightson p. persisting effects of minor head injury observable during hypoxic stress. j clin neuropsychol 1980; 2: 147-55. 2. kohler r. the management of concussion in rugby football: an update. s afr j sports med 2003; 15(1):16-20. 3. kohler r, jakoet i, mandrja s. south african rugby guidelines on the management of concussion. s afr j sports med 2003; 15(1): 26-28. 4. kohler r. concussion in sport – practical management guidelines for medical practitioners. cme march 2004. 5. aubry m, cantu r, dvorak j, et al. concussion in sport group. summary and agreement statement of the first international conference on concussion in sport, vienna 2001. recommendations for the improvement of safety and health of athletes who may suffer concussive injuries. br j sports med 2002, 36: 6-10. 6. mccrory p, johnston k, meeuwisse w, et al. summary and agreement statement of the second international conference on concussion in sport, prague 2004. br j sports med 2005; 39:196-204. 7. herring s, bergfield ja, boland a, concussion (mild traumatic brain injury) and the team physician – a consensus statement. s afr j sports med 2005, 37 (11):2012-2016. 8. collie a, maruff p. computerised neuropsychological testing. br j sports med 2003; 37: 2-3. to the editor: we appreciate the response of sports physicians kohler and patricios to our review article ‘ethically we can no longer sit on the fence: a neuropsychological perspective on the cerebrally hazardous contact sports.’ 8 they have clearly articulated a position in respect of optimal concussion management that in broad terms is highly commensurate with the recommendations arising out of our review. abreast of our own country-wide initiative, we are strongly supportive of their determination ‘to drive a nationally-focussed programme of international calibre’. indeed we are aware that they are providing a crucial educative role concerning the utility of computerised neuropsychological testing and the importance of obtaining baseline data in the south african sports concussion arena. the last thing they are doing is sitting on the fence. there is, however, a contentious issue raised by these practitioners that warrants further elaboration, and where we consider there has been a level of misrepresentation. kohler et al. state that 'contrary to shuttleworth-edwards and whitefields’ assertion that “for best practice in the implementation of return-to-play … decisions… registered psychologists are called for…”, we believe this to be impractical, both due to the scarcity and inaccessibility of such resources and the fact that computerised test batteries are designed for team physicians to implement and integrate into their management protocol of a concussed player.’ in response to the above we suggest as follows: 1. the manner in which we have been cited implies that registered psychologists are claiming a central role in return-to-play decisions per se, whereas we only claim more specifically to provide an important contribution to the decision via expertise in psychometric testing. we are entirely in agreement that computerised test batteries only form part of a clinically-oriented assessment of the concussed athlete by a medical doctor who makes the overall management recommendation. this is clear if our statement is cited more appropriately in full as follows: ‘for best practice in the implementation of such returnto-play and termination decisions using computerised psychometric instruments, registered psychologists with training in clinical neuropsychology are called for, and have an important complementary role to play’ (p. 37, new emphasis added). 2. in light of the broad infrastructure of our own national sports concussion initiative (nsci), we do not believe that a scarcity of psychological resources for the purposes optimal application of neurocognitive testing in concussion management: a professional dilemma pg100-104.indd 101 10/3/07 3:30:21 pm 102 sajsm vol 19 no.3 2007 of facilitating concussion management can be claimed within the south african context. furthermore we do not consider this to be a sound professional basis on which to argue for failure to employ an appropriate resource. 3. whereas computerised test batteries are certainly designed for team physicians to integrate into their management protocol of concussed athletes, we believe that to suggest that they are also specifically designed for team physicians to implement is highly problematic. this raises a professional dilemma in need of further elaboration, as follows. professional parameters in the implementation of computerised neuropsychological assessment on the one hand there is the argument presented by collie and maruff 2 that has been reiterated in the kohler et al. letter to the editor, in which it is suggested that neuropsychologists are not necessary to interpret the results of automated computerised reports derived in sports concussion context. a core basis for this claim is the rationale that, because exceedingly large numbers of athletes need to be evaluated, it is not practical to involve neuropsychologists exclusively. implicit in this line of reasoning, which, from the professional standpoint, is highly questionable, is that neuropsychologists are in relatively short supply and/or that their services are too expensive and will render this kind of assessment unaffordable. it is of interest that in contravention of this argument, an earlier paper by collie et al. 1 suggests that one of the most attractive features of the computerised cognitive tests in the sports context is that they allow for the possibility of electronic submission of data in a matter of seconds, and hence those data may be collated and interpreted by a deskbound neuropsychologist for immediate interpretation and resubmission back to a trainer or physician at a sporting arena in a matter of minutes. indeed, we are providing concussion management for a leading uk soccer team on this basis! in contrast to those who suggest that computer-based tests circumvent the need for neuropsychologists, others have expressed concern about the potential for misuse of neuropsychological tests with psychometric properties if they become separated from their professional – i.e. neuropsychological – source. 6 it is pointed out that the ease with which computerised tests can be administered, and automatic reports generated, may cause non-psychologists to fall into the trap of construing that the scores derived can be used simplistically as a type of ‘yes’ or ‘no’ litmus paper test for making decisions about the presence or absence of cerebral dysfunction in the individual case, with the potential for misdiagnosis. with this attitude there is a danger of reverting to the dark ages of an early actuarial approach to neuropsychological evaluation that has subsequently been abandoned in favour of a syndrome analysis model of assessment that requires the intricate interpretation of individualised differences in relation to patterns of psychometric test findings. 4,10 assessment in south africa is complicated by the multi-cultural nature of the clientele, and localised research is needed to confirm normative data for use of particular psychometric instruments in this context. 7 cross-cultural effects need to be considered in conjunction with a multitude of other possible contributing factors to variations in cognitive test performance in the cerebrally compromised individual. 9 in our clinical experience in the concussion evaluation area, there are subtleties involved in making sense out of psychometric test scores arising out of serial testing, which make the neurodiagnostic process challenging even for the psychologist with extensive training in psychometrics and expertise in brain-behaviour relations. in accordance with this more circumscribed professional outlook, the necessary role of the psychologist in terms of psychometric test usage is advocated in position statements in both the usa 3 and in south africa. 5 specifically, the health professions council for south africa (hpcsa) has presented its position on the issue as follows: ‘the professional board for psychology is greatly concerned about the growing inappropriate use of psychometric tests…… psychological tests have to be administered, scored, interpreted and reported on by registered persons, who have recognised and appropriate education and training in the field of psychometry’. 5 an exception is not made in respect of computerised psychometric tests, and these require administration and interpretation at the very least under the supervised instruction of the registered psychologist. psychologists with a training in psychometry are the only qualified professionals in a position to evaluate the relative validity of such tests. accordingly, all psychometric tests (including computerised neurocognitive tests) require approval on the basis of an expert review, and formal registration with the hpcsa for their legitimate use in this country. 5 nevertheless, it appears that in a number of instances including the usa and south africa, the computerised neuropsychological evaluation is being conducted by sports medicine clinicians without the involvement of psychologists. where there is a real problem of limited access to specialist services and/or internet facilities, this kind of practice might be professionally defensible. however, we believe that for the most part where this approach is currently being advocated this is probably not the case. the position is made even less acceptable, in terms of what is condoned by the hpcsa, when there is the use of unregistered tests. 5 a concern we have is that these kinds of arguments being advanced by kohler et al. in their letter, are being used spuriously to defend a position which allows medical doctors to perform skills which they are not trained in and which are the province of the specialist traning of psychologists. in the final analysis it is our contention that the need for the neuropsychologist’s contribution in the process needs to be acknowledged and made use of, especially for the interpretation of test data. 3,6 as indicated above, accessibility to specialist involvement of this type is greatly facilitated through internet facilities and can usefully be encouraged. 1 furthermore, with specific reference to the south african context, we would like to highlight the professional dilemma pg100-104.indd 102 10/3/07 3:30:22 pm 102 sajsm vol 19 no.3 2007 pg100-104.indd 103 10/3/07 3:30:22 pm 104 sajsm vol 19 no.3 2007 of failing to comply with the injunctions of the hpcsa (as cited above) 5 in respect of the appropriate approval and implementation of psychometric tests that is considered to be the specialist realm of the registered psychologist. within the current understanding of best practice in the health professions, there is an obligation on practitioners to provide services that stand up to scientific examination in terms of the current literature. especially it is expected that practitioners should operate strictly within the scope of their experience and training. under medicolegal scrutiny, the argument of scarcity of appropriate resources (especially when this is not strictly the case) may not be accepted as a basis for justifying less than optimal parameters for professional practice. ann edwards vicky whitefield national sports concussion initiative (nsci), psychology department, rhodes university, grahamstown notes: in south africa there is no specialist registration for clinical neuropsychology and hence the term ‘neuropsychologist’ in the south african professional setting refers to a registered psychologist who has developed a special interest area and expertise in neuropsychology. the authors are commercially involved in the development of neurocognitive screening as a component of sports concussion management in south africa and britain, using the impact programme in collaboration with the university of pittsburgh medical centre sports concussion programme, usa. the impact programme, available in english and afrikaans, is registered with the hpcsa as an approved test for use by licensed psychologists in this country. 1. collie a, darby d, maruff p. computerised cognitive assessment of athletes with sports related head injury. brit j sports med 2001; 35: 297-302. 2. collie a, maruff p. computerised neuropsychological testing. br j sports med 2003; 37: 2-3. 3. guskiewicz km, bruce de, cantu rc, et al. national athletic trainers’ association position statement: management of sport-related concussion. journal of athletic training 2004; 39: 297. 4. lezak md, howieson db, loring dw. neuropsychological assessment. 4th ed. oxford: oxford university press, 2004. 5. makgoke p. media statement by the health professions council of south africa (hpcsa). south african psychiatry review 2004; 7: 39. 6. shuttleworth-edwards ab, border ma. computer based screening in concussion management: use versus abuse. br j sports med 2002; 36: 473. 7. shuttleworth-edwards ab, kemp r, rust a, muirhead j, hartman n, radloff s. cross-cultural effects on iq test performance: a review and preliminary normative indications on wais-iii test performance. j clin exp neuropsychol 2004; 26: 903-20. 8. shuttleworth-edwards ab, whitefield vj. ethically we can no longer sit on the fence: a neuropsychological perspective on the cerebrally hazardous contact sports. s afr j sports med 2007; 19: 32-8. 9. shuttleworth-jordan ab. age and education effects on brain-damaged subjects: negative findings revisited. clin neuropsychol 1997; 11: 205-9. 10. walsh k. understanding brain damage: a primer of neuropsychological evaluation. 2nd ed. melbourne: churchill livingstone, 1991.        12 th biennial congress of the south african sports medicine association incorporating the 1 st sa rugby medical association diep-in-die-berg, pretoria 14-16 th november 2007 www.sasma.org.za / www.sasma.co.za speakers international and national expert speakers will participate in the meeting. congress committee dr demitri constantinou dr louis holtzhausen prof martin schwellnus dr christa janse van rensburg congress organiser lauren mann tel: 011 717 3372 l cell: 073 886 7970 fax: 0866363166 or 011 717 3379 email: lauren.mann@wits.ac.za congress address sasma c/o centre for exercise science and sports medicine, wits medical school, 7 york road, parktown, 2193, south africa pg100-104.indd 104 10/3/07 3:30:22 pm the comrades marathon is an ultra-distance race held annually between durban and pietermaritzburg in south africa. an interesting feature of this race is that the direction alternates each year between the two cities, with the run from durban to pietermaritzburg being uphill in nature, while the ‘down’ run from pietermaritzburg to durban is, conversely, predominantly downhill in nature. because of this it can be expected that different runners may excel at one or the other ‘direction’ and that the times will differ between ‘up’ and ‘down’ races. this is, indeed, the case, albeit with a few exceptions. in 2004, the south african journal of sports medicine (sa j sports med 2004; 16(3): 26-27) published a commentary analysing comrades marathon records by running speed rather than race time, as the race distance varies considerably from year to year and finishing times do not therefore indicate who really have run the fastest over the course. since the start and finish areas are different in each city, the distance of each race is different. this is compounded by the race being almost 90 km long, making changes in the route due to road works, road changes and local authorities, inevitable. it is therefore not surprising that the distance of the race varies even over the same direction, i.e. neither the ‘up’ nor ‘down’ runs are constant in distance. all of this makes the question of race records and fastest times over the route a difficult one. because of the fundamental differences in the nature of the ‘up’ and ‘down’ runs, each lends itself naturally to its own ‘record’ times. thus the issue that remains is that of the variation in race distance over a particular direction, which has, at times, varied by more than a kilometre. for practical purposes, the fastest time run is regarded as the record regardless of the distance. however, a more in-depth analysis of the times run over the route is interesting since the quickest time to complete the race might not necessarily equate to the fastest running speed over the course if expressed as km.hr -1 or minutes and seconds per kilometre, as indicated in the opening paragraphs. for example, in 1986 bruce fordyce ran what was then the fastest time for the ‘down’ race (5 h 24 min 07 s), which was 88.77 km long. however, he had run 5 h 27 min 18 s in the 1984 down run, which was 89.75 km long. thus although the race that year was a kilometre longer, his time was only 3 minutes 11 seconds slower. if we look at his running speed, this was actually higher in 1984 due to the longer distance of the race that year. and what of the run by alan robb in 1978 when the race was 90.1 km long and his time 5 h 29 min? and where do the two recent fastest times of the russian, leonid shvetsov slot in? it is therefore interesting to calculate the actual running speed of the top runners, using the race distances of each specific year. although such calculations do not take into account that the latter kilometres of the race will probably be run slower than the average speed maintained during the race, it is unlikely that the overall picture will be incorrect as this will have been the same for all the runners concerned. another complication in doing such an analysis is that only recently has the course been accurately measured, and this could affect the outcome of calculations of race speed and rankings. the fastest times (h: min: s) recorded for the ‘down’ run are shown below: 1. l. shvetsov 5: 20: 41 (2007) 2. b. fordyce 5: 24: 07 (1986) 3. a. kelehe 5: 25: 51 (2001) 4. b. de la motte 5: 26: 12 (1986) 5. l. shvetsov 5: 26: 28 (2001) 6. b. fordyce 5: 27: 18 (1984) it is noteworthy that the times run in 1986 and 2001 account for four of the five fastest times in which the race has been run. this is probably due to bruce fordyce and bob de la motte (see list above) having a ‘man on man’ race in the third quarter of the 1986 race, which resulted in a very fast pace. similarly, in the 2001 race a fast ‘breakaway group’ also resulted in fast times as the eventual winner, andrew kelehe, had to run at a fast pace to catch the leaders and then continued at that pace after catching and passing them. since the original article was written in 2004, it is the presence of shvetsov in the race that has made an update necessary, as he has subsequently run record times for both the ‘down’ and ‘up’ races. the order of the top runners looks somewhat different from that given in the previous paragraph when the running speed of each runner for each race is calculated. these results are shown in table i. shvetov has replaced fordyce as having the fastest speed for the race by the rather substantial margin of 3 seconds.km-1. fordyce, however, still has the second, third and sixth fastest speeds of all time and still dominates the list by claiming three of the fastest six running speeds over the course. if we consider athletes rather than performances, i.e. if only the best time of each athlete is considered, then the fastest runners on the ‘down’ run have been shvetsov (3:35.5.km-1), fordyce (3:38.8.km-1), robb (3:39.2.km-1), mattheus (3:39.3.km-1), and kelehe (3:39.7.km-1). only shvetsov is not south african. since it is somewhat difficult to perceive the implications of a difference in running speed of 3:35.5.km-1 at the top of the table and 3:39.5.km-1 at the bottom, these speeds can be used to normalise the times that would have been run by these athletes over a hypothetical race of standard distance. since the average distance of the ‘down’ race in table i has been 89.98 km, this distance was used to calculate the corresponding race times and presented in table ii. shvetsov would have been a staggering 5 minutes ahead in our hypothetical race, demonstrating clearly what a superb run he had in 2007. note, too, how close the two fastest times by fordyce are, commentary an analysis of comrades marathon records: a 2008 update correspondence: a n bosch mrc/uct research unit for exercise science and sports medicine sports science institute of south africa boundary road 7700 newlands tel: 27 21 650-4578 fax: 27 21 686-7530 e-mail: andrew.bosch@uct.ac.za a n bosch (phd) mrc/ uct research unit for exercise science and sports medicine, university of cape town sports science institute of south africa sajsm vol 20 no. 2 2008 59 pg59-60.indd 59 8/11/08 8:55:53 am 60 sajsm vol 19 no. 4 200760 sajsm vol 20 no. 2 2008 and that the sixth time on the list by fordyce is only just over a minute slower than his fastest time, suggesting strongly that the times run by fordyce were probably close to his genetic limits. if the time and speed of the fifth best performer, kelehe (3:39.7.km-1) are included, his time would be 5:29:27. if we examine the times (h:min:s) for the ‘up’ run, a similar picture emerges. the five fastest times for the ‘up’ run are: 1. l shvetsov 5: 24: 49 (2008) 2. v kotov 5: 25: 33 (2000) 3. d grishine 5: 26: 25 (1998) 4. a volgin 5: 27: 07 (2000) 5. b fordyce 5: 27: 42 (1988) 6. d grishine 5: 29: 33 (1996) as with the ‘down’ run, a performance based on running speed can be calculated (table iii). when expressed as time per kilometre, the ranking of the fastest six runners changes somewhat. although shvetsov remains the best performer, his dominance in the ‘up’ is less than in the ‘down’ run. here his time is 0.5 s.km-1 faster than fordyce, compared with the considerable 3 seconds per km in the ‘up’ run. fordyce again shows his dominance in the race, being the only athlete to have two of the fastest times on the all-time top-six list. he and shvetsov are the only runners to appear on both lists, and fordyce is the only runner to appear more than once on both lists. interestingly, it is only fordyce and shvetsov who have achieved a running speed of over 16 km.hr-1 on the ‘up’ run. the average distance of the ‘up’ races in table iii is 86.97 km. as with the ‘down’ run, this distance can be used to calculate normalised hypothetical times using the running speed of each runner from table iii. the predicted race times are shown in table iv. unlike the ‘down’ race, the ‘winning’ margin by shvetsov is not as big for the ‘up’ run, ‘winning’ by just 43 seconds. one could speculate whether 20 years of technological improvement and gains in knowledge can account for those 43 seconds. whereas 6 minutes separated the best and sixth best performance in the down race, the gap is less than half of that for the ‘up’ run. the lack of top times by south africans in the ‘up’ race is obvious. while there have been some great performances in the recent history of the race, the dominance of fordyce in the comrades marathon is apparent even 18 years since his last victory in 1990. striking, too, is the performance in 1978 of robb, which must now be considered to have been ahead of its time. returning to more recent years, however, we must recognise the greatness of runs such as that by kotov in 2000, his victory as a 46-year-old in the 2004 race, and his eighth place at the age of 50 in the race this year (2008), which must count as one of the great performances in the history of the race. table i. running speed in time per kilometre of the fastest ‘down’ comrades marathon runners rank runner year distance race time (h:min:s) speed (min: s.km -1 ) 1 l shvetsov 2007 89.30 5:20:41 3:35.5 2 b fordyce 1984 89.75 5:27:18 3:38.8 3 b fordyce 1986 88.77 5:24:07 3:39.1 4 a robb 1978 90.10 5:29:14 3:39.2 5 c mattheus 1997 89.90 5:28:37 3:39.3 6 b fordyce 1982 91.40 5:34:22 3:39.5 table ii. normalised running times based on a ‘down’ race distance of a hypothetical 89.98 km (average of distances in table i) rank runner year predicted time for 89.98 km 1 l shvetsov 2007 5:23:06 2 b fordyce 1984 5:28:08 3 b fordyce 1986 5:28:24 4 a robb 1978 5:28:47 5 c mattheus 1997 5:28:54 6 b fordyce 1982 5:29:11 table iii. running speed in time per kilometre of the fastest ‘up’ comrades marathon runners rank runner year distance race time (h:min:s) speed (min: s.km-1) 1 l shvetsov 2008 86.94 5:24:49 3:44.2 2 b fordyce 1988 87.5 5:27:42 3:44.7 3 v kotov 2000 86.55 5:25:33 3:45.6 4 b fordyce 1983 87.7 5:30:12 3:45.9 5 d greshin 1998 86.55 5:26:25 3:46.3 6 a volgin 2000 86.55 5:27:07 3:46.8 table iv. normalised running times based on an ‘up’ race distance of a hypothetical 86.97 km (average of distances in table iii) rank runner year predicted time for 86.97 km 1 l shvetsov 2008 5:24:59 2 b fordyce 1988 5:25:42 3 v kotov 2000 5:27:05 4 b fordyce 1983 5:27:27 5 d greshine 1998 5:28:05 6 a volgin 2000 5:28:42 pg59-60.indd 60 8/11/08 8:55:54 am every couple of months an incident in the sporting world triggers a passionate public debate. members of the public are quick to form and express their opinion. often the area of discussion is beyond the scope of expertise of the person contributing to the debate; however this does not deter them from doing so with gusto. the media often get involved in these debates and seek out anyone who will give them a dial-a-quote on the incident. the most recent example which springs to mind is the discussion about `wayne rooney’s metatarsal´. soon after his injury everyone from the managing director of a clothing outlet to a shoe shiner at the airport became an expert about `metatarsals´ and had an opinion about whether or not rooney would make it to the world cup. most often the opinions of the public in these specialist areas are shaped by the media, be it coaching strategies or medical problems. when covering one of these topics a responsible media reporter seeks out authoritative people with expertise in the area who are able to give an evidence-based opinion. the less responsible media seek out anyone for a `dial-a-quote´; the result – unclear or misinformation which does little to educate the public. a relatively recent trend which compounds the problem of perpetuating myths and unclear information is the growth of blogs, or discussion sites on the internet. the ready access to blog sites makes anyone who chooses an instant selfproclaimed expert. one only has to read the rugby websites to see the strong opinions expressed by some bloggers about coaching style, player fatigue and treatment of injuries. while the public debates on these sites are sometimes informative and amusing it is also the platform for the expression of radical views. it seems to be that views which are expressed loudly and frequently, shift from being radical views and assume a more central stage. where is all this leading? the point i am trying to make is that as a health professional, one shares a growing responsibility to get factual, evidenced-based and practical advice into circulation so that the end users, most often the public, have access to it. when a pseudo-scientist says that eating a certain supplement on a daily basis will make muscles grow faster than anabolic steroids, challenge the statement! when a `wannabe sports physician´ makes a public statement about player x being able to play a match with a broken bone, challenge it! the public is hungry for factual information on matters in which members of the south african sports medicine association are experts. use whatever platform you can to get the information out to the public. make sure the information is accurate and practical. only then will the public be well informed. this edition of the journal has two original research papers, one review and one short communication. the first study, by tanja oosthuyse and andrew bosch, examined the effects of various stages of the menstrual cycle on ventilatory responses during submaximal exercise. they showed that there was indeed a relationship between ovarian hormone concentration and ventilatory responses. the authors made the point that these findings have a practical relevance for research design. the next study by justin durandt and colleagues profiled the top under-16 and under-18 rugby players in the country. while there were some logical and expected differences between groups and playing positions for body composition and measurements of fitness, it was surprising to note that sprinting speed was similar between the under-16 and under-18 players. the data from this study can be used for comparative purposes, or for talent identification in the various playing positions. the review study by andrew mckune examined the recent research on asthma, airway hyper-responsiveness and airway inflammatory responses in athletes. this is a comprehensive review and provides an excellent update. the short communication by adrian kilian and richard stretch reported on the number of medical cases for spectators at the 2003 cricket world cup, including the opening ceremony. the data in this paper are useful for administrators and medical support staff involved in the planning of future sports events. i hope you enjoy this second 2006 edition of the south african journal of sports medicine! mike lambert editor-in-chief get the message out! sajsm vol 18 no.2 2006 29 editorial pg29.indd 29 6/28/06 1:49:48 pm 30 sajsm vol 24 no. 1 2012 guideline author guidelines please refer to www.sajsm.org.za for the most recent version of these guidelines. accepted manuscripts that are not in the correct format specified in these guidelines will be returned to the author(s) for correction, and will delay publication. authorship named authors must consent to publication. authorship should be based on substantial contribution to: (i) conception, design, analysis and interpretation of data; (ii) drafting or critical revision for important intellectual content; and (iii) approval of the 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[http://dx.doi.org/10.1000/ hgjr.182] [pmid:2764753] book references jeffcoate n. principles of gynaecology. 4th ed. london: butterworth, 1975:96-101.  chapter/section in a book weinstein l, swartz mn. pathogenic properties of invading microorganisms. in: sodeman wa jun, sodeman wa, eds. pathologic physiology: mechanisms of disease. philadelphia: wb saunders, 1974:457-472. internet references world health organization. the world health report 2002 reducing risks, promoting healthy life. geneva: world health organization, 2002. http://www.who.int/whr/2002 (accessed 16 january 2010). other references (e.g. reports) should follow the same format: author(s). title. publisher place: publisher name, year; pages. cited manuscripts that have been accepted but not yet published can be included as references followed by ‘(in press)’. unpublished observations and personal communications in the text must not appear in the reference list. the full name of the source person must be provided for 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submissions may be returned to authors that do not adhere to these guidelines. 1. named authors consent to publication and meet the requirements of authorship as set out by the journal. 2. the submission has not been previously published, nor is it before another journal for consideration. 3. the text complies with the stylistic and bibliographic requirements in author guidelines. 4. the manuscript is in microsoft word or rtf document format. the text is single-spaced, in 12-point times new roman font, and contains no unnecessary formatting. 5. illustrations/figures are high resolution/quality (not compressed) and in an acceptable format (preferably tiff or png). these must be submitted as ‘supplementary files’ (not in the manuscript). 6. for illustrations/figures or tables that have been published elsewhere, the author has obtained written consent to republication from the copyright holder. 7. where possible, references are accompanied by a digital object identifier (doi) and pubmed id (pmid)/pubmed central id (pmcid). 8. an abstract has been included where applicable. 9. the research was approved by a research ethics committee (if applicable) 10. any conflict of interest (or competing interests) is indicated by the author(s). sajsm vol 24 no. 2 2012 67 commentary in 2011, significant format changes were made to the super rugby, rugby union tournament. these changes created an inherent bias favouring teams within a particular country. this commentary shows the existence of the bias using logic and simulation and then makes recommendations for changes to the tournament format. fifteen regional teams compete for the super rugby title – five each from australia, south africa and new zealand (representing the current number of teams and the distribution). from 1996 to 2010 the tournament consisted of a ‘regular season’ stage, with every team facing every other team once, and a ‘finals’ stage, consisting of a knock-out tournament between the top four teams. the round robin ensured that the final log position at the end of the regular season represented the average performance of a team relative to all the other teams, with no one team being unequally weighted in the determination of the final log position. the regular season format first implemented in 2011 and continued in 2012, sees each team playing every other team from the same country (referred to as a conference) twice, and only four of the five teams from each of the other countries, resulting in 16 matches per team (see the official sanzar website for a detailed description of the 2011/2012 tournament format: http://www.sanzarrugby.com).1 the 2011/2012 format therefore ensures that each of the other teams within one’s home conference is represented twice among one’s 16 matches, but a team from another conference only has an 80% chance of being represented once. each match is weighted evenly in the determination of log points and therefore the final log position is strongly weighted towards the relative ranking of a team within their own country. given the above, it is now possible that a team which is weak, but stronger than the other teams within their own conference, can top the log, being ranked higher than teams better than they are. the most extreme example of a tournament format displaying such bias would be to have teams pair off and play 16 matches against only one other team. in this example the final log points would only represent a team’s ranking relative to their partner team, and not fairly represent their ranking relative to the other teams. teams paired in competitive bouts would be disadvantaged, and teams paired off against teams that are relatively weaker, regardless of their own absolute strength, would be advantaged. the bias within the 2011/2012 format can be demonstrated using simulation by assuming relative rankings for each team. if a weaker team can consistently finish the simulated log above a stronger team, then the tournament format can be said to create bias. the first step is to create three sets of five teams and assign objective rankings, 1 through 15, with the team ranked 1 being objectively the best. for the simulation ‘conference 1’ has teams with rankings 1, 4, 6, 8 and 10, ‘conference 2’ has teams with rankings 2, 5, 7, 9 and 11, and ‘conference 3’ has teams with rankings 3, 12, 13, 14 and 15. this arbitrary arrangement shows that conference 3 is more polarised in terms of rankings than the other two conferences, which show identical relative ranking distributions. assuming no bonus points, which may exacerbate the situation, the simulation shows that the third ranked team from conference 3 will top the log roughly 35% of the time, finish second 33% of the time, and only finish its deserved third position the remaining 32% of the time. in contrast to this result, a single round robin shows the third ranked team coming first, second and third roughly 8%, 20% and 72% of the time, respectively, a much more appropriate spread. a double round robin, with every team playing every team twice, once at home and once away, ranks every team correctly every time. each of these results is based on the outcomes of 10 000 simulated tournaments, and in each iteration which team had home advantage in each fixture was varied. in the case of the 2011/2012 format, which of the four teams from a foreign conference was played by a particular team was also varied. it was ensured throughout that every team played the same number of home and away matches. these chancemrc/uct research unit for exercise science and sports medicine, department of human biology, university of cape town david karpul, msc electrical engineering corresponding author: d karpul (david.karpul@uct.ac.za). abstract fifteen regional rugby union teams compete for the super rugby title – five each from australia, south africa and new zealand. in 2011, significant changes were made to the tournament format and these were continued in 2012. the new changes created an inherent bias, favouring teams that are strong relative to their conference, regardless of their overall strength. it is shown using logic and numerical results from simulations that teams that are weaker are able to unfairly progress to higher positions on the competition log at the end of the ‘regular’ season. the bias arises as a result of teams playing more matches against teams within their conference than other teams within the competition, and therefore the final log position represents a team’s strength relative to their own conference more than their overall strength. in the face of this evidence the tournament format should be altered to re-align with the primary goal of determining the best team in the competition. should the tournament organisers choose not to change the tournament format, it would not be unreasonable for them to face criticism for failing to implement measures to ensure fairness to each team within the competition. s afr j sm 2012;24(2):67-68. on the inherent bias in the 2011 and 2012 super rugby tournament format david karpul 68 sajsm vol 24 no. 2 2012 related changes in the format for each simulation account for the variability seen in the abovementioned results. one can include several types of match outcome variability in the model, allowing weaker teams to beat stronger teams occasionally. as it is of interest what happens on average, most types of match variability are undesirable. despite this, home advantage has been shown in the literature to play a role in match outcomes,2,3 and therefore the model includes teams being able to beat another team ranked five places higher if playing at home. for example, a team ranked ninth can beat a team ranked fourth if playing at home. the effects of travelling to a foreign country have been shown not to affect performance and therefore the travel schedule of the tournament was not taken into account.4 this particular spread of rankings, and extent of home advantage, is arbitrary and only serves to demonstrate that relative ranking within a conference unfairly affects the overall log position at the end of the regular season. it is not reasonable to expect that each of the real world conferences would have identical relative rankings, and therefore bias is inherent in the current format. in the face of this evidence, the tournament format should be altered to re-align with the primary goal of determining the best team in the competition. the bias can be resolved in one of two ways: the tournament can return to the original round robin format, or, the weighting towards intra-conference matches on the log can be remedied without changing the match format. this can be done either by weighting intra-conference matches half as much as interconference matches in terms of points or by using intra-conference matches to rank a team within a conference only and not relative to the other conference teams, essentially creating a group pool stage to the tournament. while it has been shown that bias exists, it has not been shown to which team or teams the bias benefits. from the perspective of the tournament organisers the simple establishment of the existence of bias should suffice to recommend changes to the tournament structure. should the organisers choose not to change the tournament format, it would not be unreasonable for them to face criticism for failing to implement measures to ensure fairness to each team within the tournament. references 1. sanzar rugby union. sanzar rugby home page: http://www.sanzarrugby.com (accessed 8 may 2012). 2. du preez m, walpole b. home ground advantage – fact or fallacy? a comment on the 2004 super 12 rugby competition. sajsm 2004;16:19-21. 3. morton rh. home advantage in southern hemisphere rugby union: national and international. j sports sci 2006;24;495-499. 4. du preez m, lambert mi. travel fatigue and home ground advantage in south african super 12 rugby teams. sajsm 2007;19: 20-22. pg108.indd 1. true (a) or false (b) – click on the correct answer: a diver with chronic or acute otitis would be disqualified from diving. 2. true (a) or false (b) – click on the correct answer: middle-ear barotrauma is the most common medical complication in diving. 3. true (a) or false (b) – click on the correct answer: in a study of recreational divers, 85% of the divers had a hearing test before they began scuba diving. 4. true (a) or false (b) – click on the correct answer: 27% of the divers who experienced a complication following a dive consulted with a general practitioner. 5. true (a) or false (b) – click on the correct answer: diving is a popular sport; however, there are audiological risks involved. 6. true (a) or false (b) – click on the correct answer: paget-schroetter syndrome affects primarily young (15 30 years) otherwise healthy subjects who participate in repetitive upper limb activities. 7. true (a) or false (b) – click on the correct answer: paget-schroetter syndrome affects more women than men. 8. true (a) or false (b) – click on the correct answer: it may take up to 10 months for a person with pagetschroetter syndrome to resume sports participation. 9. true (a) or false (b) – click on the correct answer: concussion is always associated with damage to cerebral arteries and veins. 10. true (a) or false (b) – click on the correct answer: second-impact injury may occur if a player returns to play prematurely following a previous head injury. 11. true (a) or false (b) – click on the correct answer: all 16 different classification systems which are used for assessing the severity of head injury have been validated. 12. true (a) or false (b) – click on the correct answer: cognitive (thinking) impairment is directly proportional to the period of unconsciousness. 13. true (a) or false (b) – click on the correct answer: the international rugby board recommends that approved headgear reduces the severity of concussion. 14. true (a) or false (b) – click on the correct answer: when a player has suspected concussion, the management for this injury takes priority over basic aspects of first aid involving cervical spine protection, airway, breathing and circulation evaluation and management. 15. true (a) or false (b) – click on the correct answer: whiplash-associated disorder is a complex clinical manifestation of neck pain, headaches, nonspecific neurological complaints, cognitive symptoms and emotional complaints. 16. true (a) or false (b) – click on the correct answer: the most widespread treatment for whiplash-associated disorder by physiotherapists includes joint mobilisations, stretches and soft-tissue massage. 17. true (a) or false (b) – click on the correct answer: a general description of the overtraining syndrome is ‘prolonged maladaptation’. 18. true (a) or false (b) – click on the correct answer: the main difference between the overtraining syndrome and non-functional overreaching is the severity of the symptoms. 19. true (a) or false (b) – click on the correct answer: according to the results of the study of meeusen et al., changes in cortisol and growth hormone were more sensitive markers of overtraining syndrome than changes in acth or prolactin. 20. true (a) or false (b) – click on the correct answer: athletes with non-functional overtraining or the overtraining syndrome show a disturbed functioning of the hypothalamic-pituitary adrenal axis. questions dec 2010 c p d q u e s t io n n a ir e cpd questionnaires must be completed online via www.cpdjournals.org.za. after submission you can check the answers and print your certificate. questions may be answered up to 6 months after publication of each issue. instructions 1. read the journal. all the answers will be found there. 2. go to www.cpdjournals.org.za to answer questions. accreditation number: mdb001/009/01/2010 (journal) sajsm original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license experiences and rehabilitation needs of runners with anterior knee pain in under-resourced communities in ekurhuleni, gauteng, south africa s h kunene, 1,3 msc; n p taukobong, 2 phd; s ramklass, 3 phd 1 physiotherapy department, university of the witwatersrand, johannesburg, south africa 2 institutional planning department, sefako makgatho health sciences university, pretoria, south africa 3 school of clinical medicine, university of kwazulu-natal, durban, south africa corresponding author: s h kunene (siyabonga.kunene@wits.ac.za) anterior knee pain (akp) has a negative impact on the quality of life (qol) of many athletes,[1,2] affecting their physical, psychosocial, emotional and mental health. this condition is most common among runners, accounting for between 15-45% of the cases of akp globally.[3] in a previous study, kunene et al.[4] found that 40% of the runners in under-resourced communities in ekurhuleni, south africa, presented with akp. this condition is was found to be more prevalent in females, the youth, and runners with a limited number of years of running experience (less than five years).[3] various factors were found to contribute to this condition. according to kunene et al.[4] tight hamstring and iliotibial band muscles, weak quadriceps muscles, weak gluteal muscles (resulting in poor hip control) and patellar tilt problems, were found to contribute significantly to akp. other factors may include tight iliopsoas muscles, tightness of the gastrocnemius complex, foot pronation, general joint laxity, leg length discrepancy, patellar glide abnormalities, and patellar hypermobility.[4,5] kunene et al.[5] also found that a heavy training load, lack of warm-up exercises during training, poor condition of running shoes, and downhill running significantly contribute to akp among runners.[6] the incidence of sports injuries and their associated problems continues to increase among athletes, more especially among those in the poorer communities who live under unfavourable socioeconomic conditions.[7] these factors may include paucity of health services, limited access to coaching professionals, and sports administrators available to organise and deliver sports events, and negative attitudes towards sports-related injuries.[7] the lack of health services could be as a result of no formal health structures with their associated support facilities and of trained professionals to deliver these services. the lack of health resources is a serious challenge in many african countries, including south africa.[8] most health facilities in the rural and peri-urban communities do not have access to full rehabilitation teams. therefore, athletes do not receive the necessary holistic treatment that they require for their injuries. while it is ideal to have access to full rehabilitation teams and the services they provide in sporting clubs, owing to their financial constraints, poorer communities do not have access to these facilities. thus many athletes end up training, and even competing, with their untreated injuries, which in turn lead to further complications. in fact, many runners may terminate their running careers due to injury complications. in professional sports, especially in urban communities, athletes are fortunate to have access to specialised sports rehabilitation services offered either by their clubs, or privately. in addition to the availability and accessibility of these rehabilitation services, there are also personal trainers and coaches for athletes in urban communities. unfortunately, this is not so in the poorer rural and peri-urban communities. in the course of this research, which was conducted at running clubs located in communities with low socioeconomic status, it was noted that some runners had stopped running as a result of their injuries, while others were running with injuries that had not been addressed. there were no rehabilitation services for injured sportspeople in these communities. background: anterior knee pain (akp) is a common knee injury resulting from overuse, and impact negatively on the quality of life of many runners. runners with akp in underresourced poor communities present with poor health outcomes. aim: to determine the experiences and rehabilitation needs of runners in under-resourced communities in ekurhuleni, south africa. methods: the study was qualitative, based on the focus group interview method. interviews were conducted with 12 runners. they were aged from 18 to 45 years and had a history of akp. permission was obtained from club managers and consent from each participant. an interview schedule with predetermined questions was used to collect the data. two researchers conducted the interview, a facilitator and moderator. the interview session lasted for 80 minutes. audio recordings of the interview session were made, transcribed verbatim and notes taken, with the final result provided in a written report. the data approach was thematic and deductive in nature. results: all 12 recruited participants participated. the participants were comprised of six females and six males, eight youths and four adults; seven had ≤5 years of running experience and five had 10 years. the following themes and subthemes emerged: 1) the negative impact of akp on health (physical, emotional and social); 2) limited rehabilitation services (availability, accessibility, affordability, adequacy and appropriateness); 3) rehabilitation needs (knowledge and professional intervention). conclusion: the study showed the negative impact of akp on health and the problem of the paucity of rehabilitation services. a community based rehabilitation programme is therefore recommended for runners. keywords: patellofemoral pain syndrome, encounters, health needs, running, poorly-resourced communities s afr j sports med 2020;32:1-5. doi: 10.17159/2078-516x/2020/v32i1a6969 mailto:siyabonga.kunene@wits.ac.za http://dx.doi.org/10.17159/2078-516x/2020/v32i1a6969 http://orcid.org/0000-0002-4880-2120 https://orcid.org/0000-0002-1803-4474 https://orcid.org/0000-0003-0451-8942 original research sajsm vol. 32 no. 1 2020 2 in order to design appropriate rehabilitation solutions for these runners, it was necessary to fully understand their experiences and rehabilitation needs. the purpose of this study was intended to determine the experiences and rehabilitation needs of runners in underresourced communities in ekurhuleni, south africa. methods study design this study was a qualitative study involving focus group interviews. the focus group interview was used to trigger responses from participants in order to clarify their experiences and rehabilitation needs. participants the twelve participating runners included long-distance, cross country, and those with a history of akp as determined by a qualified physiotherapist. these were the runners who participated in these authors’ previous studies[2,4,6] in these previous studies, the prevalence of akp was determined by the use of the kujala akp questionnaire (a subjective tool) and confirmed by objective screening tests[2,4]. participants were members of six developing running clubs in under-resourced communities in ekurhuleni, south africa. runners with degenerative conditions and traumatic injuries were excluded. the interviews took place in a quiet office at one of the training facilities. recruitment ethical clearance to conduct this study was obtained from the university of kwazulu-natal (clearance number is bfc377/15) and permission to conduct the study was given in writing by the respective club managers. a letter of invitation was sent to each club manager from the six developing running clubs requesting the participation of at least two of their runners who were a minimum of 18 years old and in training, who had undergone physical screening for akp in the authors’ previous studies.[2,4]. the letter of invitation included information on the proposed date, time and venue for the interview. data collection a focus group interview was scheduled by the researchers to collect detailed data from the participants with regard to their running experiences and rehabilitation. it was developed by the first author and validated for content by three physiotherapy experts with sports clinical and research experience. the schedule included predetermined questions about the participants’ experiences (injury and rehabilitation) and their rehabilitation needs. a pilot study was conducted to test the appropriateness of the data collection tool prior to the main study. the focus group discussion was facilitated by the first author (interviewer) and a research assistant, who presided over the process and also took care of the administrative aspects, which included the taking of notes and ensuring that all of relevant documentation was in order, e.g. information sheets, consent forms, interview notes etc. the discussion was undertaken using all 12 participants in one meeting. on the first day of data collection, the main author provided a statement of the purpose of the interview and allowed the participants to go through the study’s information sheet. all of the participants were requested to sign the consent form, and they also gave their permission for the interview to be audio recorded. the first author outlined the procedures of the meeting and encouraged everyone to participate in the discussion. the interview was conducted in english as it was the language best understood by all the participants. the first author then posed the questions as predetermined in the schedule. follow-up probe questions were also used to garner in-depth insights into the information pertaining to the main question asked. participants were encouraged to answer the questions and express their experiences freely, rather than to find consensus. the questions covered the following topics: injury experiences, rehabilitation experiences, and rehabilitation needs. the session lasted for 80 minutes. the audio recordings were transcribed verbatim and handwritten notes were taken. statistical analysis the names of the participants were coded numerically in the transcripts. the data were analysed thematically, the process being deductive in nature. the first author and research assistant reviewed the transcripts independently. they then compared their findings to reach agreement on the themes and subthemes from the data. the process included the following steps: 1) familiarisation with the data by reading and re-reading the original transcript, while listening to the audio recording, 2) development of themes and subthemes from the concepts and categories from the data, and 3) defining and naming the themes and subthemes. three rounds of discussions took place between the first author and the research assistant, where they compared the findings from the interviews to improve the credibility of the process. results all of the 12 participants took part in the focus group interview meeting. the participants included six females and six males: eight youths (18–35 years) and four adults (36–45 years). seven of the participants had less than five years of running experience and five had between five and ten years of running experience (table 1). table 1. characteristics of participants characteristics n (%) gender male female 6 (50) 6 (50) age (y) 18-35 36–45 8 (67) 4 (33) years of running <5 5–10 >10 7 (58) 5 (42) 0 original research 3 sajsm vol. 32 no. 1 2020 the participants’ injury and rehabilitation experiences, and rehabilitation needs are presented below, according to the selected themes and subthemes, together with their comments. the themes and subthemes are presented in table 2. experiences negative impact of akp on health all of the participants reported that they had experienced akp injuries in the past as a result of their long-distance running, and that they were still suffering from these injuries. their injuries had been confirmed by a qualified clinician. according to their descriptions, their pain was located on the anterior aspect of the knee below the patella. they received these injuries during training and exacerbated during races. these injuries negatively affected their health. physical impact: the participants expressed their frustrations with knee pain when running. they indicated that the pain interferes with their running to the point that they are being forced to miss training sessions and races. ‘i have had bad experiences in the past, and now too, with my knee problems. my pain has affected the way i run. in the beginning of the training or race i feel the pain, but as time goes on, the pain disappears but also comes back later as i run especially when i feel i’m getting tired (male, 38).’ ‘i also have the same challenge as my brother. mine is worse during training, especially on an uneven surface, especially here on our training ground’ (male, 30) emotional impact: some indicated that their condition negatively impacted not only on their physical health, but also on their emotional health. some reported that they sometimes become stressed about their situation and ended up being demotivated and not wanting to continue with running. ‘i sometimes get stressed when i think of how my knee problems have affected my performance as a runner, because running is my life’ (male, 36). social impact: all participants agreed that running is a social activity that keeps them connected with people, especially their friends. some use running as a means to improve their physical appearance so that they are accepted among their peers. therefore, sustaining injuries threatens not only the physical and emotional aspects of their life, but also their social life. ‘running is our way of life, it gives some of us the purpose for living. so, this knee problem i have really makes me very emotional and it takes away my sense of belonging, especially when i think of the possibility of being unable to run anymore because of it’ (female, 28). poor experiences with rehabilitation services availability: participants reported that their communities do not have rehabilitation services to address their needs as is the case in more affluent urban communities. they indicated that the clinics in their vicinity only provide basic medical services but not rehabilitation programmes for sports-related injuries. ‘this place does not have a clinic or somebody who is helping us with the injury problems we are facing. the only thing you can get is pain tablets when you go to the clinic. they don’t even give you a bandage’ (female, 31). runners end up trying to find their own solutions to the injury problems they are facing. ‘what i’m using currently is arnica oil. i sometimes ask someone to massage my knee and thigh muscle using arnica oil. i sometimes use ice baths or rub my knee with ice. when i wake up the following day, i feel better. when i don’t massage, i feel stiff and have more pain’ (female, 20). accessibility: participants indicated that rehabilitation services can only be found at the district or regional hospitals, which are located far from their communities. sometimes even the hospitals have limited services. accessing these services is a long process. participants reported that an injured person has to first visit the clinic in order to get a referral to a hospital in order to access the rehabilitation services offered there. when they finally get to the hospital, the athletes are required to stand in long queues. sometimes athletes reach the hospital but do not immediately gain access to rehabilitation services. they are sometimes given an appointment for another day. ‘this thing of hospital, sometimes i don’t see a point of even trying to go there because it’s a too long process’ (male, 40). most participants reported that the means of transport to the hospital for rehabilitation services is scarce. sometimes, because of the distance, they are required to take more than one taxi. affordability: participants reported that most of the services at the public clinics and hospitals are free of charge, especially for people who are not working or who fall into the lower income bracket. most participants agreed that private practitioners where too expensive for them which is why they do not even consider visiting them. ‘no, those people (private practitioners) are too expensive for people like us who do not have enough money. it is better to deal with your problems yourself than to lose money like that’ (female, 34). transport to clinics and hospitals is another factor that makes such services unaffordable to participants ‘i’m currently not working, and i don’t have money for transport to go to hospital and that is why i end up not honouring my appointments’ (male, 40). adequacy: the majority were of the opinion that the rehabilitation services at the hospitals and clinics are unable to prevent injuries among the running population or to offer the necessary treatment. they indicated that the rehabilitation table 2. participant themes and subthemes themes subthemes injury and rehabilitation experiences negative impact of akp on health physical impact emotional impact social impact poor experiences with rehabilitation services unavailability of services inaccessibility of services unaffordability of services inadequacy of services inappropriateness of services rehabilitation needs knowledge about their condition about self-management intervention need for injury screening need for professionals for provide services need for skilled coaching akp, anterior knee pain original research sajsm vol. 32 no. 1 2020 4 services offered by their sporting clubs are very limited – few and far between, as opposed to those offered by the professional athletic clubs in more affluent urban communities. ‘big clubs are better than us because they have their own physiotherapists or doctors to take care of them, but us we don’t have anyone because of money issues’ (male, 36). appropriateness: a few of the participants, especially those who could afford rehabilitation services, were positive about the standard of the services provided to them in hospitals and private practices. ‘i would say yes, when you eventually get to see a physio in a public hospital, you get the help you need. but i still prefer services in private’ (female, 19). they complained that the available healthcare centres do not have specialised practitioners to deal with running-related injuries (e.g. sports physicians, sports therapists). rehabilitation needs knowledge the interviews revealed that participants needed to be provided with the appropriate information regarding their injuries and how to manage them. ‘maybe if we can get some material with information so that we can help ourselves. in that way we would not need to stress a lot and go very far to get help’ (female, 29). ‘we would like to have someone to advise us on the kind of shoes we need to use when we run because i think my problem with my knee is caused by the shoes i’m using’ (male, 45). intervention participants agreed that they need the trained people in their clubs to intervene. such an intervention would include the frequent screening of injuries; supplying information on prevention tactics to avoid injury, and providing treatment for and rehabilitation techniques to deal with, the injury. ‘like in other big clubs, we also need help in terms of screening and treatment of injuries’ (male, 25). ‘i would go straight to the point. i wish our club to can have a physiotherapist who can help us with screening and treatment of injuries. even if that physio come once in a while, it’s still fine. it’s unfortunate that there are not physiotherapists who can volunteer to come and help us’ (male, 42). another intervention that they would like was the support of a person with coaching skills who could help them to improve their running performance. ‘we need trained coaches who will make us perform better, like other athletes in big countries’ (male, 22). other participants also indicated that their training facilities were not in a good state of repair and that they would like them to be improved. ‘if government can help us improve our running facilities..., we are struggling, our running tracks are not good and the grounds are not levelled’ (male, 36). discussion the findings of this study highlighted the negative health impacts of akp on participants, namely, the physical, emotional and social aspects. these findings are similar to those found in the authors’ previous survey on the impact of akp on the quality of life among 73 runners.[2] maclachlan et al. also reported extensively on the impact of akp on the psychological well-being of runners.[9] they found that runners experienced stress, anxiety, depression, and fear of movement because of akp. this suggests a need to diligently deal with akp and its associated problems. thus a comprehensive rehabilitation programme is required to address both the physical and non-physical features of this condition in order to improve runners’ quality of life. the study revealed that rehabilitation services are limited for the running population in the under-resourced communities of ekurhuleni. problems with availability, accessibility, affordability, adequacy, and appropriateness of rehabilitation services were reported. furthermore, a lack of resources and limited skills, including health professional skills, is a serious challenge in south africa, [8] particularly in socio-economically challenged communities. a low level of education, a problematical economy, and issues of crime, are some of the factors that contribute to this problem in south africa. people who live in poor communities have been found to present with poor mental and physical health outcomes.[7] as previously mentioned, a lack of resources and limited professional skills available to them, could be some of the main reasons for limiting their well-being. thus the prevalence of anterior knee pain was reported to be greatest among runners in under-resourced communities, such as those in the ekurhuleni communities.[4] this study’s results highlighted the need to address the problem of limited rehabilitation services for the running population in under-resourced communities. a need to empower runners with the relevant knowledge and skills for self-help and a need for professional intervention were identified. according to esculier et al., educating runners about the symptoms of akp and how to manage this condition is found to be effective in dealing with this type of injury.[10] however, they still need the services and support from trained professionals. rehabilitation services should be made available, accessible, affordable, appropriate and adequate for athletes in rural areas and in township communities. healthcare resources need to be equally allocated to both the more affluent in the urban areas and the disadvantaged, the latter being burdened with the additional challenges of living at a lower socioeconomic level. rehabilitation teams in the professional sports arena, including various practitioners such as sports physicians, physiotherapists, psychologists, nutritionists or dieticians, biokineticists, massage therapists, podiatrists and other healthcare practitioners, depend on the needs of the injured person. furthermore, in addition to these healthcare practitioners, personal trainers and coaches/managers also form part of the rehabilitation team. each member of the team uses his/her knowledge and skills appropriately for each phase of rehabilitation. communication and cooperation between the rehabilitation team members is vital in ensuring the continuity of care for runners. while it is ideal to have full rehabilitation teams to provide services for running clubs, it is not always possible to provide them in under-resourced communities. therefore, the transdisciplinary rehabilitation model may be the solution to issues of limited professional healthcare services in under-resourced communities. this model is client-centred original research 5 sajsm vol. 32 no. 1 2020 and promotes an ethos of cooperation among the rehabilitation team members to provide worthwhile rehabilitation services. with this approach, the rehabilitation team members are cross-trained and multi-skilled in several areas besides in their own speciality, in order to provide a holistic rehabilitation service.[11] other studies have provided convincing evidence about the importance and effectiveness of the transdisciplinary approach.[12,13,14,15] for this model to work effectively, rehabilitation team members are encouraged to consult with one another, to learn to be interdependent, to assume interchangeable roles and responsibilities, and to exchange information, knowledge and skills.[15] limitations the study presented with some limitations. the researcher could not draw participants from a larger population due to restricted resources, thus the findings from the interviews cannot be applied more widely. runners younger than 17 years and older than 45 years were not included in the study. further studies may be necessary to include a larger, more diverse and more dispersed population to better understand the experiences of runners of various ages, gender and running experiences, and found in different environments. conclusion anterior knee pain is a common but serious injury to the knee that is experienced by many runners. this study revealed that akp negatively impacts on the physical, emotional and social health of runners in under-resourced communities. the study also showed that rehabilitation services are limited in terms of their availability, accessibility, affordability, adequacy and appropriateness, and therefore in the management of running-related injuries in these communities. issues such as the need to push for the empowerment of runners through self-help knowledge and skills, as well as to bring them to the realisation that there is a need for professional intervention in order to manage their injuries, were identified. therefore, a transdisciplinary rehabilitation approach is recommended as an intervention strategy to cater for the needs of runners in under-resourced communities. acknowledgements: the authors acknowledge the support of the university of kwazulu-natal and the university of the witwatersrand for support. central gauteng athletics and running club managers are thanked for giving their permission to conduct this study. the authors also thank all the runners who participated in the study. author contributions: s h kunene conducted the study and wrote the manuscript. s ramklass and n p taukobong supervised the study and contributed to the writing of this manuscript. references 1. cheung rt, zhang z, ngai sp. different relationships between the level of patellofemoral pain and quality of life in professional and amateur athletes. pm. r 2013;5(7):568-572. [doi:10.1016/j.pmrj.2012.12.007] 2. kunene sh, ramklass s, taukobong np. the impact of anterior knee pain on the quality of life among runners in underresourced communities in ekurhuleni, gauteng. s afr j sports med 2018;30:1-6. [doi: 10.17159/2078-516x/2018/v30i1a4947] 3. cook c, hegedus e, hawkins r, et al. diagnostic accuracy and association to disability of clinical test findings associated with patellofemoral pain syndrome. physiother can 2010; 62(1):1724. [doi: 10.3138/physio.62.1.17] 4. kunene sh, ramklass s, taukobong n.p. anterior knee pain and its intrinsic risk factors among runners in under-resourced communities in ekurhuleni, gauteng. s afr j physiother 2018;74(1): a452. [doi: 10.4102/sajp.v74i1.452] 5. halabchi f, mazaheri r, seif-barghi t. patellofemoral pain syndrome and modifiable intrinsic risk factors; how to assess and address? asian j sports med 2013; 4(2):85-100. [doi:10.5812/asjsm.34488] 6. kunene sh, ramklass s, taukobong np. anterior knee pain and its extrinsic risk factors among runners in under-resourced communities in ekurhuleni, gauteng. s afr j sports med 2019;31:1-6. [doi: 10.17159/2078-516x/2019/v31i1a6090] 7. finch c, mahoney m, townsend m, et al. rural sports and recreational injuries in australia: what do we know? aust j rural health 2003;11(3):151-158. [doi: 10.1046/j.14401584.2003.00500.x] [pmid: 12950399] 8. rasool f, botha cj. the nature, extent and effect of skills shortages on skills migration in south africa. sa j hum resour manag 2011; 9(1):a287. [doi:10.4102/sajhrm.v9i1.287] 9. maclachlan lr, collins nj, matthews ml, et al. the psychological features of patellofemoral pain: a systematic review. br j sports med 2017; 51(9):732-742. [doi:10.1136/bjsports2016-096705] 10. esculier jf, bouyer lj, dubois b, et al. is combining gait retraining or an exercise programme with education better than education alone in treating runners with patellofemoral pain? a randomised clinical trial. br j sports med 2018; 52(10):659666. [doi:10.1136/bjsports-2016-096988] 11. behm j gray n interdisciplinary rehabilitation team. in: mauk k, kirsten l. rehabilitation nursing: a contemporary approach to practice. sudbury, ma: jones & bartlett learning, 2012: 5162. 12. moodley l, louw b, hugo r. early identification of at-risk infants and toddlers: a transdisciplinary model of service delivery. s afr j commun disord 2000; 47:25-39. [pmid:11455820] 13. reilly c. transdisciplinary approach: an atypical strategy for improving outcomes in rehabilitative and long-term acute care settings. rehabil nurs 2001; 26(6):216-220, 244. [doi: 10.1002/j.2048-7940.2001.tb01958.x] 14. stepans mb, thompson cl, buchanan ml. the role of the nurse on a transdisciplinary early intervention assessment team. public health nurs 2002; 19(4):238-245. [https://doi.org/10.1046/j.1525-1446.2002.19403.x] 15. king g, strachan d, tucker m, et al. the application of a transdisciplinary model for early intervention services. infants & young children 2009;22(3):211-223. [doi: 10.1097/iyc.0b013e3181abe1c3] https://doi.org/10.1046/j.1525-1446.2002.19403.x http://dx.doi.org/10.1097/iyc.0b013e3181abe1c3 km_c227-20180511093500 122 sajsm vol. 24 no. 4 2012 growing interest in producing expert performance, and increasing sport participation, has led to a number of models being proposed for optimal sporting development. using physical or psychological developmental milestones as guidelines, these models in sport were aimed primarily at identifying key stages during childhood and adolescence, and to optimise training adaptation for the child to reach his/her full sporting potential. taking into consideration the long-term developmental models, and the requirements to succeed in rugby, this review aims to prescribe the trainability of junior rugby players using a scientifically evidence-based long-term player development approach. as there have been several recent and comprehensive reviews of the literature on trainability during childhood and adolescence, the aim of this paper is to resynthesise the material and apply it to rugby. although athlete developmental models suggest that the appropriate application of training stimulus during specific periods in childhood and adolescence will influence athletic potential, recent available literature contends that this concept is inconclusive and requires further investigation. s afr j sm 2012;24(4):122-126. doi:10.7196/sajsm.357 trainability of junior rugby union players s hendricks mrc/uct research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town s hendricks, bsc med (hon) physiology corresponding author: s hendriks (sharief.hendricks@uct.ac.za) invited review in the past, coaches and sport practitioners applied adult-based forms of training to children. however, with the increase in knowledge and understanding of human development, applying adult-based training to youth was quickly questioned. this concern, together with the growing interest in producing expert performance and increasing sport participation, has led to a number of models being proposed for optimal sporting development. using physical or psychological developmental milestones as guidelines, these models in sport were aimed primarily at identifying key stages during childhood and adolescence, and to optimise training adaptation for the child to reach his/her full sporting potential. in recent times, with the advancement of the understanding of human performance and training, these developmental stages for sport have received some review.1-5 in particular, the one-dimensional approaches of these stages (i.e. either physiologically or psychologically based) have been highlighted.1-5 the next section will provide a brief overview of the distinct stages, as well as the limitations and strengths that characterise each of these models. long-term athlete development in balyi’s long-term athlete development (ltad) model, 7 stages of development are identified.6 these stages are labelled ‘active start’ (boys and girls 0 6 years of age), ‘fundamentals’ (boys 6 9, girls 6 8 years of age), ‘learning to train’ (boys 9 12, girls 8 11 years of age), ‘training to train’ (boys 12 16, girls 11 15 years of age), ‘training to compete’ (boys 16 18, girls 15 17 years of age), ‘training to win’ (boys 18+, girls 17+ years of age) and ‘retaining’. within each stage critical periods, referred to as windows of trainability,6 are identified. windows in this context refers to ‘a critical period of development of a specific capacity when training has an optimal effect’. trainability in this case, as defined by balyi, refers to ‘the faster adaptation to stimuli and the genetic endowment of athletes as they respond individually to specific stimuli and adapt to it accordingly’. the definition extends also to ‘the responsiveness of developing individuals to the training stimulus at different stages of growth and maturation.’6,7 in accordance with these definitions, the ltad model identified the windows of trainability for 5 training components: stamina, strength, speed, skill and suppleness (flexibility). the windows of trainability for stamina and strength are based on the onset of the growth spurt and peak height velocity, and the windows of trainability for speed, skill and suppleness are based on chronological age.6 furthermore, given the growth and maturation differences between boys and girls,1,5,8,9 separate windows of trainability for males and females have been proposed. the ltad model and the concept of windows of trainability have received some scrutiny in recent years. the main contention sport scientists and practitioners in sport have with the ltad model is the lack of empirical evidence to support such a long-term model,1,2,5 in particular interpretation and implementation of the concept of windows of trainability. in this regard, the purpose of these trainability windows and the long-term effects of failing to exploit a training window are yet to be elucidated.5,10 bailey et al. questioned whether these critical periods exist to help develop elite performance beyond an athlete’s genetic make-up, or achieve optimal elite performance faster.5 another criticism of the windows of trainability concept is that it is primarily based upon physiological principles.1,5,11-13 developmental model for sport participation in côté’s developmental model for sport participation (dmsp), 2 or 3 stages of development are proposed14,15 depending on whether the individual aims to reach an elite level or participate in sport for recreational purposes only. an early specialisation segment is also proposed for sports (e.g. women’s gymnastics, figure skating) that require peak performance before puberty. to fully understand each stage, terms that characterise this model need to be defined. in the dmsp, côté and colleagues make a clear distinction between ‘deliberate practice’ and ‘deliberate play’. ‘deliberate practice’ can be regarded as any training activity (i) undertaken with the specific mailto:sharief.hendricks@uct.ac.za sajsm vol. 24 no. 4 2012 123 purpose of increasing performance (not for enjoyment or external rewards); (ii) requiring cognitive and/or physical effort; and (iii) relevant to promoting positive skill development.14 in contrast, ‘deliberate play’ can be regarded as a form of sporting activity that is intrinsically motivating, provides immediate gratification and is designed to maximise enjoyment.14 in the ‘sampling’ stage (6 12 years of age) high amounts of deliberate play and low amounts of deliberate practice in various sports are recommended. after the age of 12, the athlete can either continue with a high deliberate play and low deliberate practice approach, or start focusing on specific sports. in the ‘specialising’ stage (13 15 years of age) the proposition to focus on fewer sports, with a balance between deliberate play and deliberate practice, is offered. after the specialising stage, the ‘investment stage’ is put forward, where the athlete focuses on one sport, increases the amounts of deliberate practice and decreases the amounts of deliberate play. majority of the work that forms the basis of the dmsp originates from qualitative interviews, training questionnaires and retrospective/quantitative interviews. psycho-behavioural model the abbott and collins psycho-behavioural model is an extension from the dmsp with the addition of some key distinguishing features.16 in the true sense of the word, it is believed that the abbott and collins psycho-behavioural model is not necessarily a model, but more of an approach or philosophy, since it primarily examines the role of psychology on sporting development.5 nonetheless, the term psycho-behavioural model will be used for the purpose of this review. a maintenance stage, in addition to the 3 stages proposed by côté’s model, is prescribed after the investment stage. this stage emphasises the need to increase quality of training and support for the athlete to maintain a high level of performance. abbott and collins argue that performance is a poor indicator of potential in the early stages of development as superior performance may purely be a result of early maturation.16 on the basis of this argument the authors identify determinants of potential and determinants of performance during development. determinants of potential, e.g. transferable motor or perceptual elements or psycho-behavioural elements like goal setting, are essential during the early stages of development. as the athlete matures, determinants of performance, e.g. sport-specific skill elements, become more important. another key feature of abbott and collins’ psycho-behavioural model is the ability of an athlete to successfully transfer from one stage of development to another, to eventually reach an elite level of performance.16 in this regard the crucial roles of the psychological characteristics of the athlete are highlighted. the bio-psycho-social approach and the three-worlds continuum recently, a more holistic approach to athlete development has been proposed by highly recognised researchers in the field.1,3-5 as the name suggests, unlike the previous models, the bio-psycho-social approach attempts to incorporate biological, psychological and social factors into the developmental process of the athlete. the interaction between these components is purported to be multiplicative rather than additive and the weighting of each component is different for each individual.1,3-5 these 3 factors are also highly dependent upon the objectives and motives of the individual. in the three-worlds continuum these objectives and motives are categorised into: (i) participation for personal well-being (ppw) – taking part in physical activity to satisfy needs other than personal progression; (ii) personal referenced excellence (pre) – excellence in the form of participation and personal performance; and (iii) elite referenced excellence (ere) – excellence in the form of high-level sporting performance and achievement. the main feature of this continuum is that athletes can interchange between ‘worlds’ throughout their lifespan. therefore, depending on which ‘world’ the athlete finds himself/herself in, and their stage in life, the relative contribution of biological, psychological or social factors varies. for example, a school-leaving rugby player, with the required physical attributes and necessary skill set to further his playing career (ere) for rugby, needs the right psychological tools (goal setting, imagery skills, coping strategies) and social support from coaches and parents to reach his full potential. sport specificity the aforementioned developmental models are descriptive or prescriptive models for sport in general and lack the specificity that coaches and practitioners require in practice. a key distinction between sports is whether it is open skilled or closed skilled.1,7-9,17 furthermore, open-skilled sports can be classified into invasion games, net/wall games or striking/fielding games.8,12,18 invasion contact team sports, such as rugby union, are complex and dynamic in nature, and as a consequence require a different skill set in contrast to a closed-skill sport.5,6,19-22 rugby union rugby union (henceforth referred to as ‘rugby’) is a popular international team sport. it is played by two teams consisting of 15 players each for 2 periods of 20 minutes (under 13), 30 minutes (under 16), 35 minutes (under 18) and 40 minutes (seniors).1,2,5,23,24 rugby is a highly demanding, physical, technical and tactical team sport. physical attributes required for successful participation in rugby include, but are not limited to, strength, power, speed, agility, aerobic and anaerobic conditioning, and body composition.25-27 fundamental skill requirements include catching and passing the ball, tackling, carrying the ball into contact and rucking.27,28 in addition to these general skills, position-specific skills such as scrumming and jumping in the lineouts are also needed.29 furthermore, tactical proficiency, which includes visual scanning, pattern recognition, anticipatory skills, situation knowledge, adaptability and decision making on attack and defence, are all required of the developed rugby player. in line with the needs of professional rugby, the demand to reproduce successful performances has seen an increase in the early identification, investment and development of players from an early age. however, current development programmes in rugby are largely based on traditional practices and content from adult-based studies. taking into consideration the long-term developmental models mentioned earlier, and the requirements to succeed in rugby, this review aims to prescribe the trainability of junior rugby players using a scientific evidence-based long-term player development approach. as there have been several recent and comprehensive reviews of the literature on trainability during childhood and adolescence,1-5 the aim of this document is to resynthesise the material and apply it to rugby. before a prescription of this nature can be proposed, terminologies used with regards to trainability of junior players need to be clearly defined and clarified. also, it is acknowledged that biological developmental aspects such as growth and maturation, neurodevelopment, and metabolic and hormonal processes have considerable impact on training and 124 sajsm vol. 24 no. 4 2012 development. however, a full review of these aspects is beyond the scope of this paper. windows of trainability, critical periods and sensitive periods in 1999, a review by viru et al.13 identified periods during growth and maturation that may increase receptiveness and adaptability of athletes to training. viru et al. identified critical periods that can be divided into four categories: • ontogenetic changes that influence growth, maturation and development • periods of accelerated growth • increased sensitivity to factors stimulating development • enhanced vulnerability. according to ford et al. and bailey et al.3,5 a critical period may suggest ‘a unique, special and otherwise unobtainable advantage to the effective exploitation of the period so described’. this therefore gives one the impression that if an athlete fails to exploit an identified ‘critical’ period, the athlete’s full potential will never be realised. similarly, the ltad model proposes windows of trainability (defined earlier) where an athlete’s training responses can be maximised. however, this concept, as mentioned earlier, has received much review, as it lacks substantive empirical support. also, the term ‘window’ can be misinterpreted, as ‘window’ suggests that the periods open and close. this is to say if athletes fail to exploit or utilise a window, they will be unable to maximise their full potential and this may even affect them negatively later in life.1,3,13 in contrast, ‘sensitive periods’ can be defined as ‘finite time periods during which a child is most sensitive to learning a particular skill’.13 the term ‘sensitive period’ in comparison to ‘critical’ or ‘window’ is not as close-ended and implies that an athlete is merely more responsive and adaptable to training during this period. outside the identified sensitive period, however, similar training gains can be obtained even though more effort may be required.1,3-5 physical training developmental model for rugby players the existence of periods of increased responsiveness and adaptability during development seems reasonable as it coincides with key developmental processes. furthermore, even though most sensitive periods vary for each individual, team coaches and sport practitioners usually work with large groups of athletes, therefore a practical framework of specific training components, based on the most recent evidence, will undoubtedly provide best practice guidelines to fully develop a player. in accordance with these objectives, lloyd and oliver recently proposed the youth physical developmental (ypd) model.2 even though the ypd model prescribes that all physical fitness components are trainable throughout childhood and adolescence, periods of increased emphasis and importance for each training component are highlighted based on the available evidence. each of these training components will now be discussed. aerobic conditioning having a high level of aerobic capacity is important for maintaining a high work rate in rugby. changes during middle childhood, prepubertal adolescence and post-pubertal adolescence have all been reported to influence the aerobic capacity of athletes.2,30 aerobic training gains have also been reported to occur after puberty. these aerobic training gains, however, have been attributed to increases in hormonal secretions as a consequence of growth-related changes1,31 in post-pubertal adolescence compared with pre-adolescence. according to the ypd model, more attention should be focused on aerobic conditioning as the athlete approaches adulthood (+21 years of age).2 lloyd and oliver argue that an athlete will be exposed to sport-specific aerobic activities during middle childhood and prepuberty adolescence, whether in competition or skills training. this is plausible since excessive amount of aerobic fitness conditioning at a young age may cause burnout, as sufficient circulating metabolites associated with adaptation may not be present in these young athletes to promote adaptation. for rugby union specifically, the balance between aerobic fitness and hypertrophy training is crucial for optimal player development, as an over-emphasis on aerobic fitness may negatively impact any attempts to gain muscle mass. strength and power strength and power are critical for success in rugby as they contribute significantly to the execution of the fundamental skills (tackling, carrying the ball into contact), and position-specific skills (scrumming, lifting in the line-outs). in addition, muscular strength and power reduce the risk of injury. strength and power development is multifactorial and arises from muscular, neural and mechanical functions.2,32,33 in spite of previous concerns, it is now well established that children can induce strength and power gains at an early age and improve their strength and power throughout adolescence into adulthood.2 however, the training design (frequency, volume and intensity) for inducing these gains requires some consideration.34-34 at an early age, strength and power gains can be stimulated through play and body weight resistance exercises. as the child approaches puberty, structured supervised resistance training can be safely introduced.34-36 at this point and thereafter, the adolescent should have developed proper techniques to safely perform resistance training with minimal supervision. it may be logical to assume that the rate of progression of strength and power during development will increase after puberty as a consequence of circulating growth hormones and growth factors. however, given that strength and power gains are also a function of other factors such as neural and mechanical characteristics, attributing increased gains in strength and power to circulating growth hormones and growth factors alone remains inconclusive.36 speed and agility like most invasion team sports, speed and agility are essential for success in rugby. during childhood and adolescence, speed and agility development will be influenced by changes in muscle cross-sectional area and length, biological and metabolic changes, morphological changes to the muscles and tendons neural and motor development, in addition to biomechanical and co-ordination factors.1,3 given all these factors that may contribute to speed and agility, identifying mechanisms responsible for improvements in speed and agility in childhood and adolescence remains difficult. periods of increased speed adaptation are reported to occur between the ages of 5 and 9 years.1,13 this increased adaptability may be attributed to the development of the central nervous system and improved coordination.1,13,37 a second period of increased adaptation has been reported to occur around the age of 12 years for girls and between 12 and 15 years for boys.1,37 this second period of increased speed adaptability may be a product of growth and maturation, further neurodevelopment and increase in hormone secretion.1,13 indeed, a recent review of all nonspecific and specific sprint training methods sajsm vol. 24 no. 4 2012 125 and their effects on sprinting in youth revealed that pre-pubescents (pre-phv) showed a greater training effect (percentage change) from plyometrics and sprint training (which may be linked to neural adaptation), whereas post-pubescents (post-phv) responded more favourably to strength training and a combination of training methods (which may be linked to neural and structural development).38 even though these probable periods of increased adaptability exist for speed, speed training should be incorporated in training throughout childhood and adolescence. with that said, the design and structure of this training will change from childhood to adolescence and through to adulthood. for example, during childhood, ‘speed training’ may simply be a game of fetching the ball from point a and carrying it to point b in an appropriate amount of time, whereas in adolescence, speed training may consist of training running technique and focus on leg drive, etc. in addition to strength and power training. agility is not as well studied as speed in terms of trainability during childhood and adolescence. agility is a function of strength, power and speed, and perceptual, reactive and decision-making processes. in this regard, agility can be developed in line with strength, speed and power. the perceptual, reactive and decision-making ability of the athlete can be improved through deliberate play, and as it develops, depending on his/her objectives, through deliberate practice. rugby-specific skills undeniably, developing the skills set of the player is of utmost importance for success in rugby, and should be the primary concern of the coach and sport practitioners. fundamental motor skills are common motor activities with specific observable patterns, and considered to be the building blocks that lead to specialised movement sequences required for adequate participation in many organised and non-organised physical activities, such as rugby, for children, adolescents and adults.39,40 these fundamental movement skills can be developed from as young as 2 or 3 years of age and thereafter be progressively improved, fine-tuned and tailored for sport-specific development as the athlete gets older.2 nonetheless, fundamental movement skills should always form part of the training regime regardless of level or age. in view of these skill development concepts, guidelines for developing tackling skills have been proposed by hendricks and lambert.41 there seems to be a general consensus on the activities that children need to be engaging in between the ages of 5 and 10 years. fundamental movement skills and sport skills are cultivated through games and play, with the primary goal being enjoyment and fun, with less emphasis on winning. during this stage, even though the plan may be to develop a rugby player, participation in other sports should be encouraged. training can be semi-structured and mainly consists of playing games and/or different versions of rugby (e.g. tag or touch). it is also important that parents and coaches allow learning through trial and error, and provide positive feedback where necessary. in pre-pubertal adolescence (11 14 years of age) proper instruction, demonstration and feedback from the coach for contact technical skills such as tackling, ball carrying, falling and rucking should be the focus. also, positional specific skills for scrumming and line-outs can be introduced. although a shift from primarily enjoyment and fun to a more competitive environment is made at this stage, execution of proper techniques during movement and skills training should be emphasised. additionally, because attitude and behaviour are easily influenced at this stage, parents and coaches should highlight the importance of safety during training and match play.42 after puberty, most players should have the basic skills requirements to participate in rugby. refinement and mastery of these skills should then be the focus. once these skills are mastered, the player can progress to more advanced types of training using the constraints-led approach.43 in this regard, further advancement of a player’s skills set may only occur if practice activity is structured around variability of practice and contextual interference.44 conclusion although athlete developmental models suggest that the appropriate application of training stimuli during specific periods in childhood and adolescence will influence athletic potential, recent available literature contends that this concept is inconclusive and requires further investigation.1,3-5 the complexity of sport and human development makes it difficult to attribute increased responsiveness and adaptability to training to changes in physiology alone. as mentioned earlier, other contributing factors such psychological and social factors also play a major role in the trainability of a rugby player. furthermore, it is now well established that all physical training components are trainable throughout childhood and adolescence and into adulthood.2 depending on the objectives of the athlete(s), the training structure and design need to be considered and adapted according to the developmental or training stage of the athlete. acknowledgement. the paper was commissioned by the boksmart programme, which is the national rugby safety programme implemented on behalf of the south african rugby union and the chris burger/petro jackson players’ fund. the goal of the programme is to teach safe and effective techniques, which aim to reduce the incidence and severity of injury, make the game safer for all involved and improve rugby performance. this paper also forms part of the evidence-based research in saru’s long-term participant development initiative driven by the game development division. references 1. ford p, de ste croix m, lloyd r, et al. the long-term athlete development model: physiological evidence and application. j sports sci 2011;29(4):389-402. 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[http://dx.doi. org/10.1080/02640410400021328] http://dx.doi.org/10.1080/1740898990040106] http://dx.doi.org/10.1080/02640410410001675324] http://dx.doi.org/10.1136/bjsports-2011-090548] http://dx.doi.org/10.1136/bjsports-2011-090548] http://dx.doi.org/10.1080/02640410802208986] http://dx.doi.org/10.1260/174795408784089432] http://dx.doi.org/10.1080/02640414.2012.707328] http://dx.doi.org/10.1016/j.jsams.2011.10.004] http://dx.doi.org/10.1080/02640410410001729928] http://dx.doi.org/10.1080/02640410410001729928] http://dx.doi.org/10.1177/0363546508316768] http://dx.doi.org/10.1016/s0167-5273 http://dx.doi.org/10.1016/s0167-5273 http://dx.doi.org/10.1080/02640414.2011.582508] http://dx.doi.org/10.1080/02640414.2011.582508] http://dx.doi.org/10.1080/17461391.2011.635812] http://dx.doi.org/10.1080/17461391.2011.635812] http://dx.doi.org/10.1097/00003677-200304000-00002] http://dx.doi.org/10.1136/bjsm.2009.068098] http://dx.doi.org/10.1136/bjsm.2009.068098] http://dx.doi.org/10.1519/jsc.0b013e31819df407] http://dx.doi.org/10.1542/peds.2010-0445] http://dx.doi.org/10.1542/peds.2010-0445] http://dx.doi.org/10.1080/02640418608732093] http://dx.doi.org/10.1080/02640418608732093] http://dx.doi.org/10.2165/11536850-000000000-00000] http://dx.doi.org/10.1260/1747-9541.5.1.117] http://dx.doi.org/10.1260/1747-9541.5.1.117] http://dx.doi.org/10.1016/j.ssci.2011.08.061] http://dx.doi.org/10.1080/02640410400021328] http://dx.doi.org/10.1080/02640410400021328] case report 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license cyriax syndrome in a young male professional soccer player: a case report ct panka,1 md, dsports med; py tchebegna,2 md, mph, dsports med(c) 1 general surgery, sport and exercise medicine, health and sports clinic, douala, cameroon 2 kerthan clinic, douala, cameroon corresponding author: py tchebegna (pytchebegna@gmail.com) cyriax syndrome is characterised by pain due to the irritation of the intercostal nerve as a result of the incomplete dislocation of the costal cartilage of the 8th, 9th or 10th ribs. it is a neglected cause of lower chest or upper abdominal pain with an unpredictable development. this study presents a rare case of a young male soccer player with slipping rib syndrome and offers medical insight to the clinical diagnosis and therapeutic modality of this condition. case report a 24-year-old male professional soccer player visited the sports clinic for right hypochondrium pain which had been developing for about three weeks prior to consultation. during a football match in which the player was competing, after jumping up in the air, he received a direct shock to his chest from his opponent's knee. he then felt a severe, throbbing and shooting pain in the area of his left lower rib cage (intensity 8/10 according to the visual analog scale for pain) aggravated by dorsal and lateral decubitus but felt better when he was in a standing or seated position. two days later he decided to consult the team physiotherapist who carried out conservative treatment for two weeks without any improvement. during the initial injury evaluation, the player reported that he could not sleep well due to the severe pain in the right lower rib cage near the costal-cartilage junction. the pain was replicated with rib pressure (fig. 1), with elective pain on palpation of the costal rim of the 9th and 10th ribs, during the valsalva manoeuvre and with sit-up tests. no deformity or skin changes were observed. the player had normal hemodynamic parameters of blood pressure: 110/60 mm hg, and his pulse rate was 58 beats/min. the hooking manoeuvre (curling the fingers beneath the costal rim and then instigating an upward lift) was positive without any nerve block. traction on the ribs resulted in pain when they were pushed out. a diagnostic chest x-ray was performed which showed no signs of rib fracture. conservative therapy was begun with oral analgesics (tramadol 50mg bid, acetaminophen 1g tid) and nonsteroidal anti-inflammatory drugs (diclofenac 50 mg bid) for one week. during this period, the patient was encouraged to not participate in sporting activities. dissatisfied with the persistent pain he was experiencing, he returned two weeks later complaining of the same symptoms. the persistence of this right basithoracic pain resulted in the authors establishing two separated series of local infiltrations with 1% lidocaine 10 days apart (fig. 2). thereafter, light rehabilitation exercises were initiated over a period of one month. a gradual decrease in pain was observed and the player was able to resume his professional activity after three months. this case is unique in that this player was diagnosed with a serious chest condition seldom mentioned in current sports medicine practice manuals. thus, this condition has the potential to be misdiagnosed by team doctors. the participant was informed about all aspects of the study and gave his informed and signed consent for publication. discussion slipping rib syndrome was first described in 1919 by cyriax.,[1] an english orthopaedic surgeon. the cause is most often traumatic, either directly or indirectly, which often goes unnoticed. spontaneous evolution is unpredictable and often paroxysmal. however, many healthcare professionals involved with diagnosing and treating athletes and other active individuals are often unfamiliar with this musculoskeletal condition.[2] cyriax syndrome is a neglected cause of lower chest or upper abdominal pain. the pain is due to an irritation of the intercostal nerves by the incomplete dislocation of the costal cartilage of the ribs. this study presents a rare case of a young male soccer player with cyriax syndrome and offers medical insight into the clinical diagnosis and one therapeutic modality of this condition. he came to the sports clinic reporting severe pain in the right lower rib cage near the costal cartilage junction which he has experienced for about three weeks. a chest x-ray detected nothing. after the failure of initial conservative measures, persistence of the pain led authors to initiate two separate local infiltrations using 1% lidocaine ten days apart. this resulted in a gradual decrease in pain. cyriax syndrome is an unrecognised pathology, thus it is important for team physicians to consider this diagnosis when assessing athletes with persistent chest pain. keywords: chest pain, ribs, lidocaine infiltrations s afr j sports med 2020; 32:1-2. doi: 10.17159/2078-516x/2020/v32i1a8300 mailto:pytchebegna@gmail.com https://orcid.org/0000-0002-2569-7014 https://orcid.org/0000-0003-2946-6763 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8300 case report sajsm vol. 32 no. 1 2020 2 indeed, the dislocated chondral end compresses the intercostal nerve which runs under the upper rib. the pain then spreads down to the right or left hypochondrium in the sensitive skin area of the intercostal nerve. there are very few publications on the prevalence of this syndrome. monnin et al.’s study has shown it to be 1% [3] and 1.5% in the study by sanou et al. in gabon. [6] in almost all cases, women are more affected. the low prevalence of this condition may be due to misdiagnosis and underdiagnosis, as it is very rare.[3] in most studies, from the clinical perspective, the pain is abdomino-thoracic, triggered or worsened by certain movements, developing over several days or months, more often touching the 10th rib in negative paraclinical examinations. [4-6] the findings in other studies were similar to those highlighted in this case. this patient had a right hypochondralgia aggravated by the lateral and dorsal decubitus which developed over three weeks. he sought the care of a physiotherapist without experiencing any improvement. most of the time, the trauma occurs during a high level football match, but it can also occur in other sports, such as golf, tennis, rugby or boxing.[4,7] it is necessary to know how to differentiate this pathology from the tietze syndrome (painful inflammation of the upper chondro-costal and sternoclavicular joints) and abdominal infections (gastroesophageal reflux, functional colopathy, vesicular lithiasis).[4] treatment is initially conservative, where analgesics are used, and if the pain persists, local infiltration can be undertaken. [4,8] in this study, two infiltrations were done (within the space of one week) and this patient was relieved of the pain. if the conservative approach fails, surgical treatment, consisting of resection of the last five to eight cm of dislocated cartilage is considered. [4,6] cyriax syndrome is an unrecognised pathology often confused with several painful abdominal and thoracic pathologies. its diagnosis is based on the existence of elective pain at the pressure of the costal edge of the ribs with negative radiological examinations. it is important for team physicians to consider the diagnosis of cyriax syndrome when assessing athletes with persistent thoracic or abdominal pain. author contributions: ct panka: conception and design. py tchebegna: drafting and critical revision for important intellectual content. both authors gave their consent for publication. references 1. cyriax ef. on various conditions that may stimulate the referred pain of visceral diseases and a consideration of these from the point of view of cause and effect. practitioner 1919;102:314–322. https://scholar.google.com/scholar_lookup?journal=practitio ner&title=on+various+conditions+that+may+stimulate+the+r eferred+pain+of+visceral+diseases+and+a+consideration+of+t hese+from+the+point+of+view+of+cause+and+effect&volume =102&publication_year=1919&pages=314-322& 2. davies-colley r. slipping rib. br med j 1922 ;1(3194):432. [doi: 10.1136/bmj.1.3194.432] [pmcid: pmc2415737] 3. monnin jl, pierrugues r, bories p, et al. cyriax syndrome: a cause of diagnostic error in abdominal pains. presse med 1989, 17 (1): 25-29. [pmid: 2830611] 4. barki j, blanc p, michel j, et al. painful rib syndrome (or cyriax syndrome): study of 100 patients. presse med 1996, 25(21): 973-976. [pmid: 8692774] 5. regouby y, delomez g. cyriax syndrome. pseudothreatening infarction syndrome in a patient with known angina. presse med 1988, 17(10): 488. [pmid: 2965354] 6. sanou s, belembaogo e, nzenze jr, et al. le syndrome de cyriax : à propos de 35 observations. med afrique noire 1999 ;46(6) : 331-333. 7. wright jt. slipping rib syndrome. lancet 1980; 316(8195): p632–634. [doi: 10.1016/s0140-6736(80)90294-9] [pmid: 6107417] 8. piulachs j, mathon c, guillet r. le syndrome de cyriax. lyon chir 1976; 72: 241-242. fig. 1. pressure exerted on the ribs to reproduce the pain fig. 2. local infiltrations with 1% lidocaine https://scholar.google.com/scholar_lookup?journal=practitioner&title=on+various+conditions+that+may+stimulate+the+referred+pain+of+visceral+diseases+and+a+consideration+of+these+from+the+point+of+view+of+cause+and+effect&volume=102&publication_year=1919&pages=314-322& https://scholar.google.com/scholar_lookup?journal=practitioner&title=on+various+conditions+that+may+stimulate+the+referred+pain+of+visceral+diseases+and+a+consideration+of+these+from+the+point+of+view+of+cause+and+effect&volume=102&publication_year=1919&pages=314-322& https://scholar.google.com/scholar_lookup?journal=practitioner&title=on+various+conditions+that+may+stimulate+the+referred+pain+of+visceral+diseases+and+a+consideration+of+these+from+the+point+of+view+of+cause+and+effect&volume=102&publication_year=1919&pages=314-322& https://scholar.google.com/scholar_lookup?journal=practitioner&title=on+various+conditions+that+may+stimulate+the+referred+pain+of+visceral+diseases+and+a+consideration+of+these+from+the+point+of+view+of+cause+and+effect&volume=102&publication_year=1919&pages=314-322& https://scholar.google.com/scholar_lookup?journal=practitioner&title=on+various+conditions+that+may+stimulate+the+referred+pain+of+visceral+diseases+and+a+consideration+of+these+from+the+point+of+view+of+cause+and+effect&volume=102&publication_year=1919&pages=314-322& https://doi.org/10.1016/s0140-6736(80)90294-9 sajsm 495.indd original research sajsm vol. 25 no. 4 2013 101 background. an increasing popularity of ultra-endurance events coupled with excessive or inappropriate non-steroidal anti-inflammatory drug (nsaid) use during such events could pose considerable potential risks to runners’ health. objective. to evaluate the incidence of nsaid and other analgesic use in distance runners during training, competition and recovery. methods. we performed an observational cross-sectional study at the desert race across the sand race (colorado to utah, usa) in june 2011 and the empire state marathon half-marathon, and relay races in syracuse, ny, october 2011. a total of 27 ultramarathon runners and 46 marathon, half-marathon and marathon relay runners participated in the study. surveys were distributed to runners during race registration. self-reported use of common analgesic medications during training, racing and recovery was assessed. results. among all runners at all stages, nsaids were the most commonly used analgesic medication. nsaid use by ultramarathon runners compared with all other runners was similar during training (59% and 63%, respectively; χ2=0.008; p=0.93) and recovery (59% and 61%, respectively; χ2=0.007; p=0.93). however, ultramarathon runners were more likely than all other runners to use nsaids during the race (70% and 26%, respectively; χ2=11.76; p=0.0006). conclusion. despite undesirable side-effects associated with the use of nsaids, there was a high prevalence of use in all runners, particularly during training and recovery. nsaid use during the race was significantly greater in ultramarathon runners. medical staff at endurance events need to be aware of, and prepared for potential complications related to the high use of nsaids in runners. future efforts should focus on teaching runners about the undesirable effects of medication and emphasising alternatives to pain medication. s afr j sm 2013;25(4):101-104. doi:10.7196/sajsm.495 nsaid and other analgesic use by endurance runners during training, competition and recovery j joslin, md; j b lloyd, md; t kotlyar, bs; s m wojcik, phd upstate medical university, department of emergency medicine, syracuse, new york, usa corresponding author: j joslin (joslinj@upstate.edu) ultra-endurance sports are increasing rapidly in popularity, with recent exponential growth in the amount of events and athlete participation. [1] these events are characterised by long distances (>26.2 miles) that frequently span wilderness and desert environments over multiple days. while many participants are treated for minor injuries such as blisters, sprains, tendonitis and contusions,[2] some develop more serious ailments like hyponatremia and rhabdomyolysis.[3-6] the extreme nature of these events combined with their rapidly growing participation base creates the potential for increased analgesic use, as compared with marathon and half-marathon participants, seemingly favouring nonsteroidal anti-inflammatory drug (nsaid) consumption. in all classes of athletes, nsaids are one of the most commonly used medications for the treatment of musculoskeletal pain and inflammation.[7,8] in addition to injury treatment, nsaid usage is high as a prophylactic treatment for anticipated pain,[9,10] as well as to enhance the recovery of injuries sustained during an athletic event.[11,12] while nsaids are a staple medication for the treatment of certain sports injuries, there is evidence to suggest that many athletes are consuming these medications without adequate knowledge of their intended uses or side-effects.[7,13] further, there is the potential for athletes to use nsaids in dosages exceeding the recommended amount. the most popular nsaids exert their effects through systemic cyclooxygenase (cox) inhibition, thereby reducing the amount of inflammation-causing prostaglandins produced by the body.[14] these effects are not limited to the site of injury and may be detrimental to the healing process of injuries involving bones and tendons. [11] they may also cause potentially dangerous side-effects in the gastrointestinal (gi) tract[15] and kidneys.[16,17] with such a wide catalogue of potential side-effects, it is important to examine the frequency of their use, particularly in ultra-endurance competitors and how they compare with traditional marathon runners (≤26.2 miles). numerous studies have focused on the incidence of nsaid use during endurance athlete training[5,10,12,16] and competition;[6,18] however, to our knowledge, no study has investigated nsaid and analgesic consumption at multiple timings (training, competition and rec overy) at a single event. the aims of this study were: (i) to evaluate and compare the prevalence of nsaid and other analgesic use during the training, competition and recovery phases of an endurance race in two cohorts (ultra-endurance runners and marathon runners); and (ii) to examine whether participants in both cohorts used nsaids in accordance with the recommended dose or in excess thereof. methods participants runners at two different endurance events, the 2011 desert race across the sand (rats) and the 2011 empire state marathon (esm) 102 sajsm vol. 25 no. 4 2013 were surveyed to evaluate their patterns of nsaid and analgesic use during training for an event, during a competition, and during recovery following an event. the desert rats is a 148-mile ultra-endurance run, performed over six days in individual stages of 9 50 miles per stage, across mountainous and desert terrain in colorado and utah, usa. in contrast, the esm is a more typical endurance event with runners participating in a full-marathon, half-marathon, and relays of 6 7 miles per runner. th e esm is held in central new york state annually. to the authors’ knowledge, no respondent participated in both events. data collection data were collected via an anonymous and voluntary survey reviewed and deemed exempt by the institutional internal review board (239319-1). th e survey (table 1) was distributed to runners during race registration at both endurance events. statistical analysis using medcalc (version 11.6.1), data were analysed for differences of pro portions between runners’ use of analgesia during training, competition and recovery, between those participating in the desert rats and esm races. results seventy-three runners participated in the study : 27 ultramarathon runners from the desert rats and 46 marathon, halfmarathon and relay runners from the esm. nsaids were the most commonly reported analgesics used at both races. fig. 1 shows a comparison of nsaid use delineated by reported habits of using the recommended or greater-than-recommended dose. runners in the esm were more likely than those in the desert rats race (70% v. 26%, respectively) to use nsaids during a competition (χ2=11.76; p<0.001). th ere were no statistical differences in use of nsaids between runners participating in the desert rats race when compared with those participating in the esm, during training and recovery. in both races, acetaminophen was the next most commonly reported analgesic used, followed by topical diclofenac. th e percentages of runners utilising these methods of analgesia for both race groups are shown in table 2. aspirin was not used by any participant who ran in the desert rats race, but was used by one participant who ran in the esm. narcoticbased medication was reportedly used by only runner of each race group and only during their respective recoveries. discussion when comparing the prevalence of nsaid use between ultradistance runners and marathon runners, participants reported comparable usage during training (59% v. table 1. survey distributed to runners during event registration 1. which of these do you use either occasionally or regularly during a race to help with pain and infl ammation (please select all that apply): ☐ acetaminophen (tylenol or other) do you take more than the recommended dose? yes/no ☐ ibuprofen (motrin, advil or other) do you take more than the recommended dose? yes/no ☐ narcotic-based medication (lortab, percocet, hydrocodone, oxycodone or other) do you take more than the recommended dose? yes/no ☐ aspirin (bayer or other) do you take more than the recommended dose? yes/no ☐ topical agent (voltaren, diclofenac or other) do you take more than the recommended dose? yes/no 2. which of these do you use either occasionally or regularly during recovery to help with pain and infl ammation (please select all that apply): ☐ acetaminophen (tylenol or other) do you take more than the recommended dose? yes/no ☐ ibuprofen (motrin, advil or other) do you take more than the recommended dose? yes/no ☐ narcotic-based medication (lortab, percocet, hydrocodone, oxycodone or other) do you take more than the recommended dose? yes/no ☐ aspirin (bayer or other) do you take more than the recommended dose? yes/no ☐ topical agent (voltaren, diclofenac or other) do you take more than the recommended dose? yes/no greater than recommended dose used as recommended dr esm dr esm dr esm during training during competition* during recovery r u n n er s, % 70% 60% 50% 40% 30% 20% 10% 0% fig. 1. nsaid use in the desert rats (dr) and empire state marathon (esm) runners during training, competition and recovery. th e top column represents the fraction of runners that used nsaids at dosages higher than the recommended amount. *signifi cant diff erence (p<0.001). sajsm vol. 25 no. 4 2013 103 63%) and during recovery (59% v. 61%), but with a large discrepancy of usage during a race (70% v. 26%). these results do not suggest that more ultradistance runners use nsaids during training or recovery than traditional marathon runners. the similarity in training and recovery nsaid use is expected, given that both types of events would require relatively homogenous preparation and recuperation routines. additionally, this similarity could be used as a basis for comparison between the two participant types, highlighting the major difference between the two cohorts: the elevated number of nsaid users in the ultradistance event. this difference could be rationalised by the increased duration and intensity of ultradistance events, as compared with marathons, increasing the probability that an athlete may experience pain and turn to nsaids. prophylactic use of nsaids is common in endurance events[5,10,12,16] with 59% of ironman brazil triathletes reporting consumption in the three months preceding the event,[7] a number comparable with this study where 59% of ultramarathon runners and 63% of marathon runners reported using nsaids during training. however, in addition to gastrointestinal and renal side-effects, prophylactic nsaid use may impede collagen synthesis and reduce tissue adaptation, predisposing the athlete to future injury.[16]additionally, many believe that the analgesic effect of nsaids can mask the pain of an injury and thus prevent the athlete from resting enough to allow for proper healing.[17] high levels of nsaid use during endurance events are fairly common, with self-reported usage ranging from 30% at the ironman new zealand ultradistance triathlon[18] to 61% at the 2002 boston marathon.[6] a study of 500 runners in two major north american ultramarathons showed that 60.5% of race finishers used nsaids during the race and only 28.7% of finishers did not use any medication at all,[1] and our survey reaffirms this difference. however, the significantly higher rate of nsaid consumption during a race by the ultradistance cohort v. the marathon cohort is concerning, and may put the former group at an elevated risk for adverse events. two major risks of nsaid use during an ultra-endurance race are the development of renal complications and exercise-associated hyponatraemia (eah). nsaids reduce prostaglandin synthesis in the kidney, decreasing the glomerular filtration rate and afferent renal blood flow, which may already be lowered from exercise by as much as 50%.[15-17] this combination can impair the athlete’s free water clearance, increasing the risk for developing renal disease and/ or eah. [1,5,7,8,17-21] the national kidney foundation estimates that 10% of kidney failure is associated with nsaid overuse.[15] while there are many studies that demonstrate a link between nsaid use and increased renal complications in athletes,[1,17-20] other studies show that no such correlation exists.[5] however, there is consensus that nsaids are a clear risk factor for renal disease and eah, and it is recommended that these drugs are avoided by endurance athletes, particularly in the wilderness ultramarathon setting.[21,22] an additional risk factor for nsaid-related adverse events is taking more than the recommended dose. this study did not find any significant difference between nsaid-using ultradistance runners and marathon runners with regards to surpassing the recommended dose in the period during training (31% v. 14%), a race (21% v. 25%) and recovery (19% v. 25%), respectively. these results do not suggest that ultra-distance runners are at an increased risk from taking nsaids above the recommended dose, but only as compared with marathon runners. a potential future study could look to determine and compare the amount by which each cohort exceeds the recommended dose. as attested to by its common use reported in this survey, acetaminophen may be a better alternative to nsaids for minor pain reduction, due to its milder effect on the gi tract, kidneys, and tissue regeneration.[15,20] acetaminophen’s main adverse effects come from overdose-induced hepatic toxicity, and some evidence suggests that its pain-relieving properties may be comparable to those of nsaids. [14] topical agents (such as diclofenac) are another group of analgesics used by athletes, albeit in reduced numbers (19% of ultramarathon runners during training in this study). the subcutaneous delivery to a localised site of injury makes these agents effective at treating minor acute musculoskeletal pain,[12,14,15,20,23] while avoiding many of the severe adverse reactions that nsaids carry.[14,20] encouragingly, an unpublished survey by one co-author found that 59% of athletes surveyed would modify the frequency of their nsaid use if they were better educated on their potentially harmful effects. this represents an opportunity for medical providers involved in this sport’s industry to improve the health and safety of endurance race participants. one particular opportunity for education, at least popular in ultramarathon events, is the pre-race medical briefing, where medical directors and race staff have the ability to provide evidencebased guidelines to runners before the event commences. conclusion despite the well-documented, undesirable side-effects associated with nsaid use, there was a high incidence of use in our cohort of runners, particularly during a race in the ultramarathon group. more effort should be made to inform runners about the potential hazards of nsaid misuse and to offer alternatives to oral nsaids for minor pain relief. if necessary, nsaid use should be limited to a short-term regimen, taken after the injury, and for the intended purposes only. acknowledgements. the authors acknowledge nathaniel herr for assistance with data collection and william grant for assistance with manuscript preparation. table 2. acetaminophen and diclo fenac use during the desert rats and esm races desert rats esm during training acetaminophen topical diclofenac 26% 19% 15% 4% during competition acetaminophen topical diclofenac 11% 7% 11% 2% during recovery acetaminophen topical diclofenac 11% 4% 17% 4% desert rats = desert race across the stand; esm = empire state marathon. 104 sajsm vol. 25 no. 4 2013 references 1. hoffman md, fogard k. factors related to successful completion of a 161-km ultramarathon. int j sports physiol perform 2011;6(1):25-37. 2. mclaughlin ka, townes da, wedmore is, et al. pattern of injury and illness during expedition-length adventure races. wilderness environ med 2006;17(3):158-161. 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[http://dx.doi.org/10.1016/s0885-3924(00)00125-1] original research 1 sajsm vol. 29 2017 the influence of nationality and playing position on relative age effects in rugby union: a cross-cultural comparison p e kearney, phd 1 physical education & sport sciences department, university of limerick, limerick, ireland corresponding author: p e kearney (kearneype@gmail.com) in order to provide appropriate competition, children participating in youth sport are typically assigned to cohorts based on their age in relation to a specific cut-off date (e.g. 1 january). although birth rates tend to remain uniform across the year, examination of representative youth and professional sports teams often reveals a higher number of individuals who were born in the months immediately following the cut-off date.[1] the most common explanation for this phenomenon, termed the relative age effect (rae), is that children born in the months immediately after the cut-off date are, on average, more advanced in their physical development.[2] this initial advantage is thought to be compounded as coaches may confuse this developmental advantage for a difference in potential and provide additional opportunities to relatively early maturing youths in the form of supplementary coaching or access to higher levels of competition.[1,3] rugby union is a contact sport, in which players attempt to carry a ball over their opponents’ touch-in-goal line while evading tacklers from the opposing team. consequently, physical size, strength and speed are critical both in attack and defence. as a result, rugby union is a strong candidate for raes.[1,3] indeed, world rugby[4] and national governing bodies[5] have provided guidance to coaches and administrators relating to raes and/or the variation in player maturation that these effects represent. furthermore, a number of countries have introduced modified games or weight categories in some categories of youth rugby in an attempt to negate the effect of variations in player maturation on participation and performance.[5] it was recently suggested that the existence of raes within rugby union may depend upon playing position[6], due to the diversity of body morphologies present within the game.[7] certain positions (front row, second row) might be protected from raes due to these positions requiring specific body shapes.[6] for example, second row forwards are typically the tallest players on the pitch due to their role of competing for the ball in the air, while front row forwards are typically the heaviest, due to their role emphasising direct physical competition with opponents for possession.[7] consequently, a player who shows the potential to grow to a large stature may be retained in a squad despite them not being as physically mature as his/her peers. consistent with that hypothesis, an examination of french professional rugby union players demonstrated a rae for back row forwards, but not for front row or second row forwards.[6] no rae was found for french backline players. the aim of this study was to examine whether the same finding held in other countries. methods a review of an online database (http://www.itsrugby.co.uk/) revealed the names of 8751 senior male professional rugby players of australian, english, new zealand or south african nationality. removing players for whom no date of birth was available, or who were born before 1975, produced the eventual sample of 6663 players. players were grouped according to the main positional division in rugby union into forwards or backs, as well as to playing units[7] (see figure 1). consistent with the selection year (starting in january in australia, new zealand and south africa; september in england), players’ birth dates were categorised into four quarters. chi-squared goodness of fit tests were used to examine whether the distribution of births differed from that of an even distribution. cohen’s w provided a measure of effect size, with w values of 0.1, 0.3 and 0.5 indicating a small, medium and large effect size, respectively. where significant chi-square results were found, standardised residuals (sr) provided a post-hoc test to identify in which quarters there were significant deviations from the expected frequencies. a positive sr indicated a higher than expected number of births in that quarter. a negative sr indicated a lower than expected number of births in that quarter. srs ≥ ±1.96 were deemed noteworthy. results overall results are presented in table 1. when considering all players, raes were evident in all four samples. with regard to specific positions (table 2 and figure 1), the hypothesis that raes would be more prevalent in back row players than in background: recent research in a french context suggested that relative age effects (raes) in rugby union may be influenced by playing position; specifically, that raes may be more pronounced in back row players who do not have as extreme an anthropomorphic profile as other forward positions. methods: in the present study, dates of birth of 6 663 players from four nations (australia, england, new zealand, south africa) were analysed for relative age effects. results: the hypothesis that raes would be more pronounced in back row players was not supported. south african rugby was an obvious outlier due to the finding that raes were present across all playing units. these results suggest that late maturing players have been disproportionately lost to the south african system across all positions. conclusion: nation-specific youth sport culture appears to be more important than playing position for determining who is at risk of raes in rugby union. keywords: birth date, team sport, talent development s afr j sports med 2017;29:1-4. doi: 10.17159/2078-516x/2017/v29i0a1886 mailto:kearneype@gmail.com http://www.itsrugby.co.uk/ http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1886 original research sajsm vol. 29 2017 2 front row or second row players was not supported. while the australian sample showed a rae in back row players (χ2(3, n = 198) = 9.3, p = 0.03, w = 0.22) but not in front row or second row players, the english and new zealand samples showed no rae for any of the forward units. the south african sample showed a rae in all three positions (front row, χ2(3, n = 668) = 26.0, p < 0.001, w = 0.20; second row, χ2(3, n = 342) = 19.2, p < 0.001, w = 0.24; back row, χ2(3, n = 588) = 21.9, p < 0.001, w = 0.19). in terms of backline players, raes were observed for outside backs in the new zealand (χ2(3, n = 182) = 12.9, p < 0.001, w = 0.27) and english (χ2(3, n = 284) = 17.4, p < 0.001, w = 0.25) samples, and for english half backs (χ2(3, n = 213) = 7.9, p = 0.05, w = 0.19). again, the south african sample was distinctive in that an over-representation of players born in the first quarter of the year, and an under-representation of players born in the last quarter of the year was observed for all backline positions (half backs, χ2(3, n = 480) = 47.1, p < 0.001, w = 0.31; centres, χ2(3, n = 352) = 30.2, p < 0.001, w = 0.29; and outside backs, χ2(3, n = 508) = 23.8, p < 0.001, w = 0.22). discussion the hypothesis that back row players would be more likely to demonstrate raes than front row or second row units was not supported. while the australian data is equivalent to that reported for french players in a previous study[6], data from the remaining countries showed different patterns. within the english and new zealand samples, no forward position showed a pronounced bias, while outside backs showed the strongest rae. within the south african sample, all positions showed small to moderate raes. it therefore appears that table 1. relative age distribution of rugby union players according to nationality and playing unit country population n % q1 % q2 % q3 % q4 p w sr q1 sr q2 sr q3 sr q4 australia all 1007 30 25 23 23 0.01 0.13 3.4 -0.3 -1.6 -1.6 forwards 526 29 27 23 21 0.02 0.14 2.1 1.0 -1.0 -2.1 backs 481 31 22 22 25 0.01 0.15 2.8 -1.5 -1.2 -0.1 england all 1519 30 25 24 21 0.01 0.14 4.2 0.3 -1.1 -3.4 forwards 833 29 26 23 21 0.01 0.12 2.4 0.7 -1.1 -2.0 backs 686 32 24 24 20 0.01 0.18 3.6 -0.4 -0.4 -2.8 new zealand all 1199 29 26 24 21 0.01 0.11 2.6 0.4 -0.5 -2.5 forwards 688 29 24 22 24 0.06 0.10 backs 511 28 28 27 17 0.01 0.18 1.4 1.2 0.9 -3.4 south africa all 2938 34 26 22 18 0.01 0.23 9.5 0.6 -2.8 -7.3 forwards 1598 33 24 23 20 0.01 0.20 6.6 -0.8 -1.7 -4.1 backs 1340 34 27 22 16 0.01 0.27 6.9 1.8 -2.3 -6.3 n, number of participants; q, quarter of birth; p, p-value; w, cohen’s w effect size; sr, standardized residual . table 2. relative age distribution of rugby union players according to nationality and playing position country population n % q1 % q2 % q3 % q4 p w sr q1 sr q2 sr q3 sr q4 australia front row 198 33 23 22 22 0.09 0.18 second row 130 23 28 27 22 0.65 0.11 back row 198 30 30 21 18 0.03 0.22 1.5 1.5 -1.1 -1.9 half backs 158 31 21 23 25 0.32 0.15 centres 124 34 24 21 21 0.14 0.21 outside backs 199 30 21 22 27 0.20 0.15 england front row 364 26 26 26 22 0.61 0.07 second row 187 32 28 20 20 0.05 0.20 1.8 0.9 -1.4 -1.3 back row 282 31 25 22 22 0.08 0.15 half backs 213 30 23 29 18 0.05 0.19 1.5 -0.7 1.2 -2.0 centres 189 30 23 27 20 0.21 0.15 outside backs 284 35 26 19 20 0.01 0.25 3.2 0.5 -2.1 -1.5 new zealand front row 272 30 23 21 26 0.17 0.14 second row 161 27 27 21 25 0.60 0.11 back row 255 30 24 25 21 0.22 0.13 half backs 179 32 23 23 21 0.13 0.18 centres 150 21 29 32 18 0.04 0.23 -1.1 1.1 1.7 -1.7 outside backs 182 30 30 26 14 0.01 0.27 1.3 1.4 0.4 -3.0 south africa front row 668 33 25 24 19 0.01 0.20 4.0 -0.2 -0.8 -3.0 second row 342 35 21 23 20 0.01 0.24 3.7 -1.5 -0.6 -1.7 back row 588 33 25 22 20 0.01 0.19 3.8 0.0 -1.5 -2.3 half backs 480 36 27 23 14 0.01 0.31 4.8 0.8 -0.7 -4.8 centres 352 34 30 20 16 0.01 0.29 3.4 1.8 -1.7 -3.5 outside backs 508 33 26 21 19 0.01 0.22 3.7 0.5 -1.6 -2.7 n, number of participants; q, quarter of birth; p, p-value; w, cohen’s w effect size; sr, standardized residual . original research 3 sajsm vol. 29 2017 youth sport culture is potentially more important than playing position for determining who is at risk of raes in rugby union.[8] the presence of raes at senior level is symptomatic of underlying problems with talent development and youth sport programmes.[1] specifically, the over-representation of players born in the first quarter of the year and the underrepresentation of players born in the final quarter of the year suggests an inherent inefficiency within talent development systems, whereby players are accessing support and opportunities on the basis of current maturation status rather than future potential. as such, the data tentatively suggest that the talent development processes operating historically within south african rugby were significantly biased towards early maturing players to a greater extent than the talent development processes operating in other countries. identifying whether progress has been made on this issue would require the analysis of age-graded data.[3] within rugby union in england, a reversal of the rae has been identified [9], whereby relatively late-born players were more likely to progress to elite player squad status, despite the existence of a pronounced rae within the academy cohorts from which these elite players graduated. mccarthy et al.[9] argue that the small minority of players who managed to overcome the disadvantages of being born relatively late in the year benefitted from their additional struggles, likely through the development of a range of psychological skills/characteristics. care is needed when interpreting this finding, which illustrates the complexity of raes. many youth players may be disadvantaged by the existence of raes, including late-born individuals early in their development and early-born individuals later in their development. given the inevitability of variation in development among youth cohorts, attempts to fully remove raes may prove fruitless and even counterproductive. a more appropriate route for talent development programmes may be to focus on developing a broader understanding of the processes influencing both early and late developing players amongst administrators, coaches and the players themselves. conclusion in summary, the results suggest that raes may have influenced talent development in south african rugby to a greater extent than in other major rugby playing nations. further research is required to determine if raes are still present within the south african system, and, if present, the extent to which raes influence the process of talent development. acknowledgements: portions of this research were completed while the author was a lecturer at the institute of sport, university of chichester. the author would like to thank dr pj smyth for his helpful comments on an earlier draft of this manuscript. conflict of interest: none fig. 1. the influence of playing position on relative age effects in (a) australian, (b) english, (c) new zealand, and (d) south african professional rugby players. q, quarter of the year in which players were born. 0 5 10 15 20 25 30 35 40 front row second row back row half backs centres outside backs % p la y e rs b o rn playing position q1 q2 q3 q4 (a) 0 5 10 15 20 25 30 35 40 front row second row back row half backs centres outside backs % p la y e rs b o rn playing position q1 q2 q3 q4 (d) 0 5 10 15 20 25 30 35 40 front row second row back row half backs centres outside backs % p la y e rs b o rn playing position q1 q2 q3 q4 (c) 0 5 10 15 20 25 30 35 40 front row second row back row half backs centres outside backs % p la y e rs b o rn playing position q1 q2 q3 q4 (b) australia england new zealand south africa original research sajsm vol. 29 2017 4 references 1. cobley s, baker j, wattie n, et al. annual age-grouping and athlete development: a meta-analytical review of relative age effects in sport. sports med 2009;39:235–256. [doi: 10.2165/00007256-200939030-00005] 2. nutton rw, hamilton df, hutichson jd, et al. variation in physical development in schoolboy rugby players: can maturity testing reduce mismatch? bmj open 2012; 2:e001149. [doi: 10.1136/bmjopen-2012-001149] 3. lewis j, morgan k, cooper s-m. relative age effects in welsh age grade rugby union. int j sports sci coach 2015; 10:797– 813. [doi: 10.1260/1747-9541.10.5.797] 4. douglas m. world rugby: putting players first. relative age effect. dublin: world rugby. n.d. http://playerwelfare.worldrugby.org/?documentid=110 (accessed 29 november 2017). 5. lambert m, forbes j, brown j. age-group vs weight-group rugby. cape town: boksmart, 2010. http://www.sarugby.co.za/boksmart/pdf/boksmart%202010age%20vs%20weight%20category%20rugby.pdf 6. kearney pe. playing position influences the relative age effect in senior rugby union. sci sport 2017; 32:114-116. [doi: 10.1016/j.scispo.2016.06.009] 7. delahunt e, byrne rb, doolin rk, et al. anthropometric profile and body composition of irish adolescent rugby union players aged 16-18. j strength cond res. 2013;27: 3252–3258. [doi: 10.1519/jsc.0b013e3182915ea6] 8. lidor r, arnon m, maayan z, gershon t, côté j,. relative age and birthplace effect in division 1 female ballgame players – the relevance of sport-specific factors. international journal of sport and exercise psychology 2014;12: 19-33. [doi: 10.1080/1612197x.2012.756232] 9. mccarthy n, collins d, court d. start hard, finish better: further evidence for the reversal of the rae advantage. j sport sci 2016;34:1461–1465. [doi: 10.1080/02640414.2015.1119297] http://playerwelfare.worldrugby.org/?documentid=110 http://www.sarugby.co.za/boksmart/pdf/boksmart%202010-age%20vs%20weight%20category%20rugby.pdf http://www.sarugby.co.za/boksmart/pdf/boksmart%202010-age%20vs%20weight%20category%20rugby.pdf sajsm vol. 27 no. 3 2015 63 there are many questions about youth rugby for which there are no immediate answers. at what age should the young players specialise? how often should they practise? how many matches should they play in season? science has lagged behind in providing clear answers, and in many cases decisions about the development of the game at this level have to be made based on logic and intuition. as a result, opinions may differ and controversy may prevail. recently a panel of experts representing different aspects of youth rugby was asked a series of questions about this sport, the aim being to examine the answers given from different perspectives. the overall goal was to identify where agreement does or does not exist. to make this exercise worthwhile, it was important to have respected panellists with expertise in different areas. the following panellists were invited to participate: justin durandt, manager of the discovery high performance centre, sports science institute of south africa (sa), currently studying towards his phd on talent identification in youth rugby players; dr sharief hendricks, a postdoctoral fellow internationally renowned for his research on the tackle in rugby; dr mike marshall, a medical doctor with expertise in rugby medicine and youth rugby; andries roux, a rugby coach and teacher working with primary school children; and dr eugene hare, an expert in youth rugby and physical development, and current ceo of the blue bulls rugby union in sa. the questions posed to each panellist and their individual responses follow. should players already start specialising in rugby at u13 age-grade level? what are the potential long-term implications from a health and wellbeing, player performance and player retention point of view if they do specialise early? justin durandt: it is important that we define what we mean by ‘specialisation’ or ‘early specialisation’. i define specialisation as the situation when one engages in intense training in one sport (usually all year round), which results in one not being able to participate in other sports. early specialisation refers to when this type of specialisation happens while a child is still in primary school. a recent review by jayanthi et al.[1] in the american orthopaedic society of sports medicine journal showed that most studies show no benefit of early specialisation in late-specialisation sports (which applies to most team sports, including rugby). on the contrary, they showed benefits for early sampling (playing a number of sports) and only specialising later in high school. we conducted a study which showed that only a small percentage of boys from u13 craven week (24%) go on to play at u18 craven week.[2] therefore the focus should not be on choosing a small group of elite players at this level, but rather on trying to keep as big a group as possible interested in and playing the game. that is why we should prioritise skill development and participation in primary school and only focus on performance in high school. this does not mean one cannot have a competitive element, as this is also important, but it must be properly managed not to become the main focus. talent identification and high-performance programmes should only start in high school at u16 level, when players are physically mature enough to confirm that they have the physical characteristics required for playing rugby at an elite level. sharief hendricks: short answer, no. at the u13 age-grade level players should be exposed to a variety of sports. with that said, at this stage the player may choose (and key here is the word ‘player’) to be more competitive in one or two sports, and to be less competitive (i.e. recreational) in other sports. a number of factors may incline this age group towards competitiveness; for example, access to facilities and equipment, social environment and self-efficacy. mike marshall: there are two considerations here: early specialisation within rugby and early specialisation in only rugby. both have negative implications. early specialisation within rugby may limit the development of certain skills that may be of value later (e.g. ball skills, positional play, etc.). also, specialisation prior to ‘positiondetermining’ growth may limit the development of all-round skills that may well be of benefit later (remember, springbok lock eben etzebeth was a wing while still in his teens!). early specialisation in only rugby denies the young athlete the opportunity to experience other sports, to develop a wider range of physical and social skills, and to achieve success on a broader front. andries roux: no. i think that they would be better off playing or practising a number of other sports too. this would have a definite influence on their skill set – rugby training can be very restrictive with regard to skill training – and make them more coachable (willing to learn) later on in their careers. eugene hare: in sa, specifically in rugby, the early developers are mainly chosen for provincial sides, but are not always the most talented. a small number of u13 provincial players also play provincial rugby at u16 and u18 level.[2] positive features of such identification procedures are that children are directed towards sports for which they are physically and psychologically best suited. this in turn means they will probably obtain good results and enjoy their training and participation more. another factor is physical injury, which is an inherent risk in sport participation, and to a certain extent must be considered an inevitable cost of athletic training and competition. it is essential that talent in sport be identified at an early stage to make certain that the correct exercise and training are employed to ensure peak performance at a later stage. how early in the year should u13 age-grade level rugby players start with rugby-specific conditioning and preparation, given that most schools generally have other sporting codes that are also seasonally based? justin durandt: the key to conditioning at a primary school level is to try and achieve general athletic development in children. this means that a school should have a general conditioning programme, irrespective of which sport the child is participating in. boys only achieve peak height velocity (fastest growth rate) at about 14 years of age, and are usually near their adult height at 18 years of age. this means that many of the physiological traits required for success in elite sport are only evident when children reach the age of 15 18 years. most parents and their children won’t know which sport they are best suited to until they are between 15 and 18 years of age. the conditioning programme for the different sports should be coordinated so that there is continuity in conditioning between the winter and summer sports. this will reduce the rugby-specific conditioning period required. the under-13 rugby: what are the issues? a panel discussion commentary 64 sajsm vol. 27 no. 3 2015 children would still require 2 3 weeks of rugby-specific activities so that their bodies get used to the contact and sport-specific demands. sharief hendricks: keeping in mind the previous two questions, the competitive rugby season for the u13 age group should last about 6 months, with a 1-month complete lay-off in-between. in the southern hemisphere this means april through to august. rugby-specific conditioning and preparation can start 4 weeks prior to the first match. mike marshall: four weeks prior to the first full-contact match might be the ideal time for preseason training in this age group. however, a number of factors make this difficult. firstly, 4 weeks is probably appropriate for the majority of players in this age group, but perhaps not long enough for those who play at an elite level. secondly, this 4-week period must be properly ‘periodised’ if the injury risk is to be minimised. so, for example, the first week may include only one fitness session, the second week, two sessions of skill and fitness, the third week, three sessions of fitness and skills, and the fourth week, three sessions of fitness and skills plus some contact. thirdly, there is always a logistical problem in trying to fit in preseason training (e.g. for rugby) during the playing season of another sports code (e.g. cricket). this could be addressed by having a less congested fixture list (see later discussion). lastly, using the school holidays for preseason training remains a good idea, but is notoriously difficult to achieve due to family commitments, supervision concerns, motivation and so on. andries roux: two or 3 weeks prior, depending of course on how busy the school’s extracurricular programme is and how many of the boys are actually involved in other activities. having boys choosing to participate in a rigorous rugby preseason instead of, for example, athletics cannot be in their long-term best interest. eugene hare: the sa school sports calendar is a challenging topic. very little planning is done to accommodate different sports and also include children in various sports activities. a situation analysis with regard to the demands that rugby makes on young rugby players has revealed that the basic skills and abilities a player needs are handling (catching and passing), running, kicking, speed and endurance. physical abilities required are strength, endurance and flexibility. the three most common sport activities for boys are rugby, cricket and athletics. through proper planning the abovementioned demands can be addressed in a training year planner, which can be as follows: the challenge for the coach is to draw up a plan for a coaching strategy for the year, a weekly plan, as well as a plan for each session. this will ensure proper player management and the prevention of fatigue. at u13 age-grade level what should: the maximum length and duration of the rugby season be?; the maximum number of rugby matches played in a season be?; and the maximum number of seasonal matches played per week be? please elaborate on your answers. justin durandt: the average season, depending on the province and level of the school participating, runs from april to june (12 weeks plus an additional week for craven week). in many traditional rugbyplaying schools, boys often play two matches per week, which equates to 24 matches in a 3-month season. this may exclude provincial trials and warm-up provincial games. rugby is a contact sport (meaning that players require greater periods of recovery compared with non-contact sports) and therefore the number of matches and their frequency should be controlled and monitored. a suggested guideline is a maximum of two games per week (including practice and trials matches) or 25 per season, excluding craven week itself. there should be a minimum of a day’s break between games, but preferably two. i also think that guidelines are required for primary school tournaments, including the number of games played in a specific time period (days). sharief hendricks: as noted, 6 months with a 1-month complete lay-off in-between. during 1 week, one competitive match (in full kit, etc.) and one practice match. during only 3 of the 4 weeks in a month will competitive matches occur. every now and then two competitive matches a week may be played. at this level playing the sport (i.e. more game time) is good as it builds the player’s capacity to meet the physical demands of the game, and affords the opportunity to execute the technical and tactical skills within a competitive game environment. i would also assume that the player enjoys playing the game. the reason for the regular breaks is to avoid the sport becoming a burden on other aspects of the child’s life, and also to allow time to engage in other sports. players will also most likely be playing contact rugby outside of the formal team setting. mike marshall: i simply don’t know what the ideal number of games per season is for this age group, although i would opt for a ‘less is more’ approach. my ‘guesstimate’ would be between 10 and 15 matches per season: 10 for the vast majority of ‘average players’ and 15 for the elite players (i.e. those selected to play for representative teams). i think one game a week, plus perhaps a few extra during a school’s rugby festival, is enough for the average player in this age group. in addition, i think no more than a further five or six games should be allowed for the elite players playing for representative teams. playing more than this in a season means too little time for recovery from ‘bumps and bruises’ and minor injuries, increasing the risk of more significant injury. perhaps more importantly, playing more matches than this means too little time for other informal physical activities, schoolwork, hobbies, family time and simple downtime (i.e. mental recovery). andries roux: i think that here the players who go the furthest with the trials or provincial games are at far greater risk. they are the best and most talented players – sometimes just boys who developed fastest – in each age group, and should be looked after. as outlined in my earlier reply, once the trials begin and they begin training with their provincial teams, things get completely out of hand. in 2014 playing time in u13 matches was increased from 20 to 25 minutes per half. i think that this added to the problem. i don’t think any one player should be allowed to play more than 25 matches in our (blue bulls) season, which already equates to almost two per week. this is going to get complicated in the case of players who are involved in further trials and additional practices. eugene hare: unfortunately there is no proper benchmark for competitions in all regions in sa. there are also different competition structures that influence when players start to play competitively. the important factors are the number of games per season and the number of games per week. it is recommended that u13 players should not play more than 20 25 matches per season (1 000 1 250 minutes). november december active rest january february preseason (athletics) march early season (rugby) april may midseason (rugby) june july peak season (rugby) july october recovery period (cricket) sajsm vol. 27 no. 3 2015 65 how frequently should players train or practise rugby in a week, in the preseason and in-season periods, at u13 age-grade level? justin durandt: if they are playing other sports, then one practice session per week during the preseason training would be sufficient. if they are not playing other sports, then two sessions per week could be completed in the preseason. during the season they should have two practice days and one match day a week; if they play a second match in that week this takes the place of one of the practice sessions. total training load is one of the key principles that needs to be considered when planning practice and game time, and is the minutes that the players practise × the intensity of each session (on a scale of 1 10). sharief hendricks: twice a week (this includes the practice match) in the 4 weeks leading up to the first match. the same schedule applies for the in-season period. mike marshall: i think u13 rugby players should train/play three times a week. preseason training can be done safely three times a week, as long as the training programme is correctly structured/‘periodised’. during the season two training sessions and one match per week seem ideal to me, especially if the matches are played on the weekend. andries roux: preseason: once a week; in season: three times per week (or twice, depending on whether game day falls on a training day). typically monday, tuesday and thursday should be enough. in pretoria game days are mostly on tuesdays and thursdays. eugene hare: the level of competition will determine the amount of time spent on the abovementioned. usually primary schools play during the week; therefore the specific game days will determine the amount of training days. it is therefore very important to do the ‘hard’ and ‘tough’ training in the preseason and to do specific (specialised) training in the competition phase. the amount of training in the preseason should therefore be more than during the competition phase: preseason three to four times a week, not exceeding 60 minutes, and peak season two to three times a week, not exceeding 60 minutes. what is the minimum time u13 age-grade level players need between matches to optimise physical recovery, recover from bumps and bruises, and prepare properly for the next match? justin durandt: one day minimum, 2 days is optimal. sharief hendricks: between 24 and 48 hours. mike marshall: for matches during the ‘routine’ season, a period of 1 week is required for adequate recovery (both mental and physical). in the less than ideal situation of a school’s rugby festival, i think a minimum of 2 days’ rest should be enforced between matches. andries roux: at least 2 days. eugene hare: physical recovery will differ between players and also from game to game. the coach will be the person to determine this. two days of recovery might be sufficient. how much contact rugby and contact preparation training (sessions per week, time per session, intensity of contact, preseason, inseason) is enough for optimal rugby coaching and player development at u13 age-grade level? justin durandt: contact practices are required to teach contact skills and conditioning. there should be contact in the preseason to prepare the players for in-season matches. the amount and intensity of contact needs to be increased gradually during the preseason. the amount of contact during the in-season may depend on the number of matches in a specific week. if two matches are being played with one practice, you may choose to limit contact in that week. one should always attempt to keep the contact practice as far as possible from the match days, to reduce the likelihood of players having bumps and bruises for their matches. sharief hendricks: contact is good for preparing players to meet the demands of rugby. in my opinion contact training needs to be considered along a continuum, where you may have controlled lowintensity technical training at the one end (far left), and high-intensity, dynamic match conditions skill training on the other (far right). with this in mind, i think controlled low-intensity technical training can start in week 1 of preseason, with the demands of the contact situation increasing to match conditions up to week 4. during preseason 50% of the weekly training schedule should be in preparation for contact. during in-season at least 40% of the time should be spent on contact technique training. the intensity, level of control and frequency of contact can vary, depending on the goals of that week, what was done in previous weeks, etc. a practice match during the week can form part of this contact training. mike marshall: there is simply no easy answer to this question. the rough and tumble of informal games played by boys of this age group is part of this training, but is obviously unquantifiable! my ‘guesstimate’ for an adequate rugby programme would be to spend 25% of time on contact training. so, for example, if there are two 1-hour training sessions per week, 30 minutes of one of those sessions would be a contact session – i.e. specifically match play and rucking practice. together with the weekly match, that would mean 90 minutes of contact per week during the season. the intensity of the contact training session should be modified to suit the players’ fitness level, intensity of the past/pending match, specific training requirements of the team, etc. this contact should be seen as separate from the physical training of specific skills drills like tackling practice, wrestling drills, scrummaging, and so on. as discussed earlier, preseason contact training should only be introduced in the last week of preparation. andries roux: it is necessary to include contact in all training sessions, as it is an invaluable part of any player’s skill set. start as slowly as possible to ensure that everybody understands the skill, before lifting the tempo towards the level that you expect during games. in-season, contact should be kept to a minimum. each and every training session should include aspects of every skill required: physical abilities like agility, strength and speed, ball skills like catching and passing, contact skills like tackling and rucking, etc. eugene hare: contact at primary school level is not as intense as in senior rugby. therefore an analysis of the game should give more accurate statistics of the game and specifically the contact situation. different defensive structures will determine which players (position in the team and in defence structures) will make the most tackles. this might differ from senior rugby. contact confidence skills training should be part of preseason training and at all sessions, and be lowered in-season. how does one maintain sufficient balance between rugby and other important developmental aspects of life in u13 age-grade level rugby players? justin durandt: one needs to educate both parents and teachers. many schools are hiring private coaches who are judged on the team’s results, and therefore they have a ‘win at all costs’ attitude. 66 sajsm vol. 27 no. 3 2015 we need to strive to achieve three goals with children playing rugby and any sport: personal development, participation and performance. [3] the key focus at primary school should be to create opportunities for participation and personal development. sharief hendricks: i think the roles and responsibilities and the relationship between the coaches, parents and players are primarily to find the optimal balance. also, unnecessary pressure on the player should be avoided. in the same vein, excessively reinforcing rugby achievements may give the player a false sense of ability, which may affect him/her later in life. mike marshall: this is the essence of this panel discussion, i.e. maintaining a balance between rugby and all the other developmental aspects of a child’s life is crucial. unfortunately there are no easy solutions to this matter, as it is complicated by numerous factors. these include, but are not limited, to: • time constraints (e.g. a busy school/academic programme, more extracurricular school responsibilities than ever before, participation in other sports codes, busy family life, etc.) • logistic difficulties (e.g. too few coaches, inadequately skilled coaches, inadequate school sports facilities, etc.) • pressure to succeed (e.g. misguided parents, scholarships and bursaries, ambitious coaches) • age (e.g. mental and physical immaturity). the (utopian) solution lies in providing a structured approach to exercise, where the needs and desires of each individual are met. of course this is just about impossible to provide, so perhaps a more utilitarian approach would include the following guidelines: children in this age group should be encouraged to play a different sports code during each of the four school terms. this would have the beneficial effects of: • necessitating a shorter rugby season (see earlier discussion on this topic) • de-emphasising any one particular sports code • facilitating better all-round physical development of the child. parents and teachers must insist on the provision of sufficient time for homework, assignments, etc. social interaction around the child’s sports participation should be encouraged. andries roux: this is very difficult. parents are guided by the whims of coaches and teachers. coaches earn more the more they coach, and teachers are sometimes not necessarily specialists in their field. there are no clear guides as to what should be done and how it should be implemented. short-term success sometimes gets in the way of common sense. the only way to find a balance is by coordinating the entire school’s extracurricular programme. i think that it is important that a team of experts provides clear guidelines, keeping in mind that these activities form a part of a learner’s whole education and should not be detrimental towards other aspects. i think for starters there should be a date on which a preseason is allowed to start. there should also be guides as to how many training sessions should be allowed per week, etc. educating the coaches is going to be very important. eugene hare: player management is the key to success. if the player is identified as talented in a specific sport, then proper planning and management can be executed. career planning can be done and growth and development can determine the players’ long-term development. how much rugby played is enough to maintain passion and enthusiasm for the game, for long-term player retention, and for effective long-term player development pathways for u13 rugby players wanting to play rugby at the elite adult level? justin durandt: we need to study the occurrence of injuries at primary school level and come up with definitive guidelines on training and match time in relation to injury risk. sharief hendricks: côté’s developmental model for sport participation[3] and biopsychosocial approach serve as good reference points to answer this question. in these models the goals and objectives of the individual set the course for recreational participation or elite performance. with this in mind, if a player enjoys playing rugby and wants to play and train more (with no outside pressures), then he should be fully supported by providing the optimal environment in order to afford the player this opportunity. mike marshall: the ‘balance of activities’ argued for in the questions above is the way to maintain long-term sports participation. when any sports participation becomes onerous and is no longer fun, long-term participation is most unlikely. in addition, the development of better ‘allround’ motor skills can only be of benefit to the growing rugby player. andries roux: this is also a tricky problem because some parents believe in keeping their kids busy, so the moment you train less some parents are just going to fill the gap with another activity. i have often wondered if changing the matches/competitions to include some other physical activities isn’t the solution. by making games/matches shorter and including other competitions to eventually determine the result, one would be encouraging coaches to focus on more than just game-plans, moves and set patterns. for example, the game is played with two 12/15-minute halves. all the boys then participate in an activity or two against each other. whether they compete in 40 m sprints, do push-ups, run ladders, bridges, do hand-eye coordination drills, kick, or catch up-and-unders, the results of these ‘games’ would then also count towards the result on the day. this would encourage coaches to include a wider range of physical exercises/activities in their training. i think that a programme that addresses these physical abilities would benefit other sporting codes. they could adopt a similar model in their programmes. this in turn could result in less sport-specific coaching and take the emphasis off the ‘win at all costs’ mentality that is currently such a serious concern. children would learn through practising a wider range of skills on a regular basis. i think that by doing this one would actually be improving the skill sets of the players immeasurably. eugene hare: proper scientific research is needed to ensure that the amount of rugby played by 13-year-old children supports their growth and development as well as other physiological and social development. the length of the season, amount of games, length of active rest and participation in other sports will be influential factors. references 1. jayanthi n, pinkham c, dugas l, patrick b, labella c. sports specialization in young athletes: evidence-based recommendations. sports health 2013;5(3):251-257. [http:// dx.doi.org/10.1177/1941738112464626] 2. durandt j, parker z, masimla h, lambert mm. rugby-playing history at the national u13 level and subsequent participation at the national u16 and u18 rugby tournaments. s afr j sports med 2011;23(4):103-105. 3. côté j, hancock dj. evidence-based policies for youth sport programmes. int j sport policy politics 2014; jun 26:1-15. [http://dx.doi.org/10.1080/19406940.2014.919338] s afr j sports med 2015;27(3):63-66. doi:10.7196/sajsm.8078 sajsm 595 (commentarty).indd commentary 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license brace yourselves: esports is coming c kemp, bmedsci (hons)1; p r pienaar, msc (med)1,2; d e rae, phd1 1 health through physical activity, lifestyle and sport research centre & division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, south africa 2 department of public and occupational health, amsterdam public health research institute, vu university, amsterdam umc, amste rdam, the netherlands corresponding author: c kemp (chadleyk@outlook.com) esports is an emerging global phenomenon, defined as a type of organised professional video game competition. [1] owing to the diverse nature of gaming, esports has also been described as a conglomeration of competitive video games. [1,2] currently, it has a reach of 454 million fans with an estimated global market revenue of $1.1 billion (r16.5 billion). [2] on its current trajectory, with a compound annual growth rate of 14%, esports is expected to have a total global audience of 645 million fans by the year 2022. [2] while the global extent of esports currently appears to be overshadowed by mainstream sports, such as soccer, cricket and rugby, it certainly has garnered substantial public interest. [2] compared to traditional us sports, esports dominates viewership figures in major us sports leagues, including their national basketball association, national hockey league and soccer leagues. [3] in the us alone, esports viewership is estimated to reach 84 million by 2021, second only to the national football league, with a projected 141 million viewers. [3] moreover, these developments are not isolated to the us but extend across europe and asia. [2] lucrative commercial partnerships have tracked the increased numbers of viewers, driving large-scale tournaments and events comparable with major traditional sports. tournaments often take place in large, sold-out stadiums with multimillion-dollar prize pools. [4,5] this has been accompanied by both endemic sponsorships (e.g. computer and gaming brands) and nonendemic sponsorships (e.g. beverage brands) for teams and players. [2] considering individual earnings, esports joins the ranks of traditional sports, with elite players earning as much as $3.1 million (r46.5 million) per single major event. [4] this has resulted in esports becoming a highly competitive environment, understandably placing pressure on these athletes to perform optimally. discussion training unlike traditional sports, esports is host to a dynamic competitive landscape. this comes in the form of an evolving “meta” (a colloquial term describing the current optimal playstyle) since the pace, style and features of the games change, following regular or seasonal gameplay updates. with a relatively short-lived career, marked by an early age of peak performance, [6] esports athletes must continually adapt their playstyles or risk losing their competitive status. it is reported that esports athletes may dedicate as much as 14 h per day to practices or matches, [5] risking potential burnout or fatigue. this has inspired some professional teams to incorporate wellness programmes into their schedules to improve player performance and career longevity. elite esports organisations invest large amounts of money into residential gaming houses for players and coaches to enable them to follow strict training schedules over the competitive season. an article published in the inven global website (27 may 2018) details the typical training day schedule of esports athletes as follows: wake-up at 10 am followed by training from 11 am to 7 pm, after which players may stream games to their followers until bedtime (2 am). although training schedules are similarly adopted among professional teams, they may change over in the noncompetitive season. nevertheless, these cumbersome routines demonstrate the discipline required to be proficient as an esports athlete. in fact, michael phelps honoured esports athletes at the game awards 2016 ceremony, saying: ‘there’s absolutely no question to me the level of skill, training and devotion it requires to become a professional gamer’. challenges despite these developments, esports has been challenged in its widespread acceptance as a reputable form of competition. this follows persistent efforts by the esports industry to prove its legitimacy, which included it being used as an exemplar at the pyeongchang olympic winter games in 2018. esports partners have also since engaged in discussions with the international olympic committee (ioc) regarding its inclusion as a demonstration title at the 2024 summer olympic games in paris. additionally, there has been continued deliberation surrounding its inclusivity as a sporting activity, particularly with regards to the sedentary nature of esports. [7] a statement made by the ioc at the 7th olympic summit indicates that there is continued debate around the physicality of competitive gaming, such that the notion as to whether esports can be considered a sport in the traditional sense, requires further discussion. according to jenny et al. (2016), [5] the components of a sport must include the elements of play, rules, competition, be comprised of skill (as opposed to chance), have a broad following, including physical skills (i.e. ‘skilful and strategic background: competitive gaming (or esports) is an emerging phenomenon with a field of over 454 million fans globally. despite its tremendous popularity and commercial support, esports is not widely understood. it is also disregarded as a reputable or credible form of competition. the international olympic committee (ioc) contends that esports may be considered a sporting activity, but this is limited to the basis of its sedentary nature and poor governance. discussion: these authors present evidence to inform and clarify misconceptions surrounding esports among the broader scientific community. they also encourage researchers to engage in further work into the phenomenon of competitive gaming with regard to health and performance, resulting in a better understanding of esports and guiding its development as a credible, competitive entity. keywords: electronic sports, cybersports, computer gaming, professional gaming s afr j sports med 2020; 32:1-2.doi: 10.17159/2078-516x/2020/v32i1a7596 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7596 https://orcid.org/0000-0002-2584-6585 https://orcid.org/0000-0001-9159-9474 https://orcid.org/0000-0001-6677-3688 commentary sajsm vol. 32 no. 1 2020 2 use of one’s body’) and governance. esports tick the first five elements, and few people would argue against the cognitive effort and skill required in gaming. gamers utilise an array of cognitive processes (e.g. attention, reaction time, working memory) and fine motor skills (e.g. to use the mouse or keyboard); [6,8] all of which are central to their proficiency and require significant cognitive effort. the sticking point seems to be around the physicality of gaming. indeed, sport should be viewed holistically, without necessarily prioritising athleticism. however, gaming is, at least for the most part, considered to be a sedentary activity. while there are sports like archery and shooting, which involve a limited degree of physical activity during competition, the physical training that these athletes undergo to successfully shoot is comparable to that of more traditional athletes. in this regard, current forms of video gaming simply do not compare. given the increasing popularity of motion-based video games (or exergames) and virtual reality, which may involve more gross motor activity, perhaps esports will be viewed as a more credible sport in the future. governance although esports mimics traditional sports in many ways (debate around physicality notwithstanding), arguably the greatest barrier regarding its inclusivity as a credible sport, is its lack of organisational structure. [7] this issue was raised by the ioc previously in 2017 in response to failed attempts of governance by various stakeholders to ensure the implementation of policies. the world esports association (wesa) is the purported representative body for esports players, teams and organisations. it is also an official signatory of the world anti-doping agency. wesa inspires little confidence, however, to ensure or enforce compliance of regulatory practices. these should include: random drug testing, player transfers, drafting of player contracts, and arbitration. since esports titles remain the intellectual property of their respective game publishers, there is at least some level of authority regarding the enforcement of standardised rules and penalties of misconduct. this may extend to tournament organisers, such as esl formerly known as electronic sports league, who maintain these rules, as well as their own rules, including matters involving fraud and deception. broad policy reform under the jurisdiction of a global esports authority, however, is necessary to allow unbiased control and enforcement of policies regarding the matters of players, organisations and tournament organisers. conclusion esports continues to show record growth as a front-runner in the digital ecosystem. despite esports being a highly competitive and commercially-invested form of competition, it currently remains segregated from the sporting community. a call to refine the current definition of sport to be more inclusive, without favouring physicality, [1] has initiated progress regarding the inclusivity of esports. in celebrating a new era in digital entertainment and sporting activity, researchers are encouraged to be objective and use the esports platform as an opportunity to extend health and performance research. indeed, it is research of this nature which may drive the policy reform of esports. furthermore, research should act to bridge the gap in the current understanding of esports and guide its development to become credible and broadly recognised. perhaps its acceptance as a credible sport is not a matter of fact or opinion, but simply a matter of time. funding: the first author received a joint scholarship from the national research foundation and the university of cape town. conflicts of interest: the authors declare no conflicts of interest. references 1. mccutcheon c, hitchens m, drachen a. esport vs irlsport. in: cheok a, inami m, romão t eds. advances in computer entertainment technology. ace 2017. lecture notes in computer science, vol 10714. springercham .:531-542. [doi. 10.1007/978-3-319-76270-8_36] 2. newzoo. global esports market report 2019 | light version. newzoo group bv, 2019. https://newzoo.com/insights/trendreports/newzoo-global-esports-market-report-2019-lightversion.(accessed 20 october 2019). 3. activate consulting. activate technology & media outlook 2018. activate inc, 2017. https://www.slideshare.net/activateinc/activate-tech-mediaoutlook-2018 (accessed 23 october 2019). 4. wong s. esports prize pools rival traditional sports in 2019. gaming street, 2019. https://www.gamingstreet.com/esportsprize-pools-rival-traditional-sports-in-2019/. (accessed 28 october 2019). 5. jenny se, manning rd, keiper mc, et al. virtual (ly) athletes: where esports fit within the definition of “sport”. quest 2017; 69(1):1-18. [doi. 10.1080/00336297.2016.1144517] 6. kokkinakis av, cowling pi, drachen a, et al. exploring the relationship between video game expertise and fluid intelligence. plos one 2017; 12(11):e0186621 [doi. 10.1371/journal.pone.0186621] 7. hallmann k, giel t. esports competitive sports or recreational activity? sport manage rev 2018;21(1):14-20. [doi. 10.1016/j.smr.2017.07.011] 8. bonnar d, castine b, kakoschke n, et al. sleep and performance in eathletes: for the win! sleep health 2019; 5(6):647-650. [doi. 10.1016/j.sleh.2019.06.007] https://newzoo.com/insights/trend-reports/newzoo-global-esports-market-report-2019-light-version/ https://newzoo.com/insights/trend-reports/newzoo-global-esports-market-report-2019-light-version/ https://newzoo.com/insights/trend-reports/newzoo-global-esports-market-report-2019-light-version/ https://www.gamingstreet.com/esports-prize-pools-rival-traditional-sports-in-2019/ https://www.gamingstreet.com/esports-prize-pools-rival-traditional-sports-in-2019/ once again, after the successful hosting of the football world cup, sport has shown how it can unite a nation, independently of the politicians. as we bask in the afterglow of the world cup it is worth contemplating how the buzz which was experienced in the country for those four glorious weeks can be maintained. each time the country has done well in international sport there has been heightened public spirit, which declines with a relatively short half-life. it does not take a sharp mind to realise that if we want to maintain this spirit, which is so important for nation building, we need to improve the level of competitiveness of our top sportsmen and women. we need to be able to compete with the best and win with style and humility. when we lose, we need to do so with grace and courage. now the hard part – what do we have to change in our current structure to achieve this? do we have the answers and, most importantly, resources to achieve this? it was by chance that i came across the findings of a task force which was commissioned by sport and recreation new zealand (sparc) (www.sparc.org.nz). the goal of this task force was to compile strategies for talent identification and development in new zealand. in other words, their goal was to develop a strategy which would improve the sporting competitiveness of the nation. the talent development framework was finalised in 2006. it was developed by a cross-sector task force, the talent identification and development taskforce, after research into talent identification and development methodologies which existed internationally. their recommendations were appealing for two reasons: firstly they were simple, realistic and based on common sense, and secondly, if these recommendations are implemented there is a very real chance that the competitiveness of our sports participants on the international level will increase. a summary of the main points of the task force follows (with my comments in italics): 1. talent is dynamic and multi-dimensional, and cannot be accurately or easily predicted – this is so true and points to the simple fact of letting children play and letting talent emerge naturally. our responsibility is to create opportunities for play. specific talent identification programmes are expensive, producing many false positive results. 2. gifted athletes can emerge at any stage of development – let’s change the paradigm of selecting more physically mature children over children who may mature later. throwing the selection net wider will most certainly yield a more productive catch. 3. environment, genetics, mental ability, physiology, and support are all key to developing talent – we all know that, let’s just put it into practice. 4. environment is the easiest element to influence – let’s address the imbalance in facilities in the country with as much vigour as was put into building the magnificent stadia for the soccer world cup, and allow the champions to flourish. 5. some common attributes of top performing athletes are as follows: ● they were very active as children ● they specialised in one sport later in their development ● they were motivated by the joy of sport rather than winning ● they had access to coaching from an early age. schools have an important role in achieving these goals. while some schools are already doing an admirable job, others are hamstrung by a lack of equipment and resources and should be upgraded and supported so that they can offer these minimum requirements for talent development. let’s make coaching a viable career track so that talented coaches can be attracted and supported. 6. playing a range of sports developed a more advanced skill set for an athlete than concentrating on one sport from an early age – let’s give physical education its rightful place in the curriculum so that children can be exposed to a range of sports which develop their motor skills and physical ability, laying the foundations for champions. 7. inhibiting factors were a lack of social and financial support, and fathers who demanded success – the truth lies somewhere between disinterested parents and parents who are too pushy. parents need to understand their role clearly and provide support without placing too much pressure to perform on the child. solutions to problems are sometimes so clear and obvious and for this reason are missed. reading the new zealand guidelines gave me confidence that the solution for improving the competitiveness of our sport is right before us and can easily be implemented if we all have the same vision. mike lambert editor-in-chief sport in action – simple steps to develop and manage talent a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial 30 sajsm vol 22 no. 2 2010 original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license strength and conditioning practices of franchise-level cricket trainers l pote1, phd; g king2, msc; cj christie1, phd 1 department of human kinetics and ergonomics, rhodes university, grahamstown, south africa 2 cricket south africa, northlands, south africa corresponding author: l pote (l.pote86@gmail.com) the game of cricket is one of the oldest organised sports and is played throughout the world.[1] it is constantly growing in popularity, particularly with the introduction and development of one-day and twenty/20 cricket.[2] with these developments, the physical demands placed on the players are often substantial especially as individuals are often required to participate in multiple competitions, increasing the length of their seasons.[3] despite this, the research on how this has impacted the demands placed on players is still limited.[3] it is important to understand these demands so that the appropriate strength and conditioning training and injury prevention practices can be implemented. lately, there has been more interest in the physical demands of cricket with research focusing mainly on injuries.[4] however, there is limited literature showing how strength and conditioning practices are being directed towards preparing cricketers for the demands imposed by the game. furthermore, while our understanding of these demands has increased, if and how strength and conditioning trainers use this information is not known. therefore, it is not clear how strength and conditioning trainers prepare players for the demands of the game. cricket places the body at risk as injuries in the sport are common.[4] fast bowlers are the most prone to injury, followed by batsmen and lastly fielders/wicketkeepers. common injuries include stress fractures of the lumbar spine (fast bowlers), muscle strains of the lower limbs (batsmen) and impact injuries to the upper limbs (fielders/wicketkeepers).[3] however, how strength and conditioning trainers use this information is not clear as there is limited literature on the strength and conditioning practices implemented by trainers to manage demands and reduce the risk of injury.[3] most of the research that has been done in the strength and conditioning field has looked at sports which have different demands to cricket.[5] only one study has examined the training practices of cricket trainers and this was limited to university and high school level trainers.[1] there is limited literature on higher end trainers particularly at the professional level. therefore, the purpose of this study was to determine the strength and conditioning practices that franchise level trainers implement at a professional level. methods experimental approach to the problem this investigation was an online, survey-based, mixedmethods examination of the strength and conditioning practices of franchise level cricket trainers in south africa. the survey required trainers to describe the practices they implement. participants the sample consisted of five head strength and conditioning trainers (age: 33 ± 3 years) from the different franchise-based cricket teams in south africa. the small sample size and the fact that only male cricket trainers were investigated may be seen as a limitation of this study. ethical clearance was granted by the department of human kinetics and ergonomics ethical standards committee for research involving human participants (rhodes university, grahamstown, south africa, ru-hsd-16-11-001). this included permission from cricket south africa (csa). all trainers were informed of the benefits and risks of the investigation. survey the questionnaire was based on a previously validated cricketspecific survey that looked at the strength and conditioning practices of high school level trainers[1] and consisted of three main sections: 1. general questions focusing on background information including age, gender, experience and qualifications. 2. strength and conditioning questions looking specifically at physical testing as well as strength and conditioning for background: the purpose of this investigation was to determine the strength and conditioning practices implemented by cricket trainers and coaches at an elite level. methods: an online survey, adapted from previous strength and conditioning questionnaires, was sent to trainers currently working with the franchise cricket teams in south africa. the survey consisted of four main sections including a general strength and conditioning, cricketspecific and injury prevention category. results: the results indicated that trainers (n = 5) implement planned sessions throughout the different phases of the season and that certain injury prevention practices are applied. furthermore, player workload is monitored for all disciplines (batsmen, bowlers and fielders). conclusion: these results can be used as a tool to educate coaches and trainers to ensure the correct strength and conditioning practices are implemented. additionally the study showed that strength and conditioning practices at the elite level can be implemented without specialised equipment and facilities, which is important for teams that are constantly travelling. lastly it showed the importance of looking at all aspects of health and skill related fitness. keywords: training, injury prevention, workload, monitoring s afr j sports med 2020;32:1-5. doi: 10.17159/2078-516x/2020/v32i1a7786 mailto:g06p1630@campus.ru.ac.za http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7786 https://orcid.org/0000-0003-1371-2616 https://orcid.org/0000-0003-0727-0014 original research sajsm vol. 32 no. 1 2020 2 flexibility, speed, agility, plyometrics and strength development. 3. cricket-specific questions examining the strength and conditioning practices for each specific discipline (bowling, batting and fielding/wicket-keeping). trainers were required to complete each question and could not proceed to the next question until the previous one had been completed. at the end of the survey a general comments section was added where trainers were encouraged to mention any areas of interest that should be taken into account or considered from a strength and conditioning perspective. procedures an electronic letter describing the investigation was sent via email to the strength and conditioning trainers for the different franchise teams. this included an explanation of what the survey would entail and an electronic link (google forms) that the trainers needed to access in order to complete the survey. it was highlighted that by accessing the survey link, consent would be automatically given; however, all information would remain anonymous. trainers were informed that they could exit the survey at any time without any further consequences. lastly, it was specified that feedback would be provided via email if requested, but no trainer or franchise names would be included in the feedback response. statistical analysis the survey was made up of predominately fixed response (quantitative) questions. all responses were collated in realtime using an online survey platform (google forms) and exported to microsoft excel for further group and individual analyses. the descriptive statistics tool in microsoft excel was used to analyse the quantitative data. only the “comments” section contained open-ended (qualitative) data. here the data were collated and scrutinised for specific major and minor themes. this was completed by analysing data according to methods used in previous strength and conditioning surveys.[5] these themes were then used to determine the results of this section. results background information absolute values were used to present the results. the basic demographic data of the trainers is displayed in table 1. physical testing all trainers indicated that their players were required to participate in some form of physical testing (fig.1). every trainer completed the physical testing of their athletes in the preseason. in the in-season, four trainers indicated re-testing while in the off-season, three trainers indicated this. in the yo-yo intermittent test, maximum push-ups in one minute and skinfold measures, were the most common tests used, followed by the 10-, 20and 40 meter sprint test. training practices and equipment all of the trainers reported prescribing flexibility, agility, plyometrics and strength training during some of the season. four out of the five did speed training. in terms of stretching, all of the trainers required players to stretch before (dynamic) and two after (static) a practice or match. only one trainer required stretching at the gymnasium. the equipment and drills used by each trainer for the different training practices as well as the phase of season and sessions per week are described in table 2. cricket-specific conditioning and workload monitoring four out of the five trainers indicated that they implement different conditioning practices for each discipline (bowling, batting and fielding/wicket-keeping). for bowlers there was more focus on the posterior chain, the core, mobility and the lower body, whereas for batsmen there was a larger focus on table 1. basic demographic data of the trainers n gender (n=5) male 5 female 0 experience (n=5) > 5 years 3 < 5years 2 education (n=5) degree* 4 diploma/certificate* 1 *degree/diploma/certificate refers to a biokinetics, sports science or certified strength and conditioning specialist qualification as indicated by trainers. n, number of trainers fig. 1. physical testing parameters implemented by the trainers original research 3 sajsm vol. 32 no. 1 2020 the upper body, mobility and the core. there was no mention of specific conditioning practices for fielders. in terms of monitoring, all of the trainers indicated that they implement some form of workload monitoring. this was through cricket south africa’s online monitoring platform, “cricket clinic”. the most common monitoring practices included the number of deliveries bowled, the load lifted, running intensity and distance, number of throws, average heart rate, as well as training load through session ratings of perceived exertion (srpe) and duration. injury monitoring and prevention all of the trainers indicated that they kept a record of the injured players and the injuries they received. three trainers specified that fast bowlers were the most prone to injury while two indicated that fielders were more susceptible to injury (these were fielders included in all the disciplines of the game). the most commonly injured areas for bowlers were the hamstrings and lower back region, whereas the shoulder was the most commonly injured area for fielders. batsmen were most prone to impact injuries. all the trainers indicated that they implemented some form of injury prevention exercises, mainly during the pre-season and in-season periods. exercises included pre-habilitation exercises which focused on the main injuries that occurred (gluteus and deltoid muscles strengthening and stabilising), core work (prone bridge), hip flexor mobility and posterior chain strengthening. lastly, in the comments section, it was noted that trainers prioritise strength over cardiovascular training and that players’ hip flexors and hamstrings are often tight due to prolonged periods of sitting (such as during travelling). discussion this is the first study that has examined the strength and conditioning practices implemented by trainers at a professional level. the most important finding was that there was planned strength and conditioning sessions in the different phases of competition. further, that these trainers monitor workload and put in place injury prevention practices (pre-habilitation, core, mobility and posterior chain work) based on the injuries that occur for each discipline, something considered to be good practice.[6] this is in contrast to a study done on trainers working with adolescent players at a high school and university level (non-professional players) where it was reported that this did not occur.[1] furthermore, all the trainers in the current investigation possessed some form of degree or diploma/certificate in strength and conditioning which was not the case at the adolescent level.[1] therefore, it would seem that trainer and coach education is important if the correct strength and conditioning and injury prevention practices are to be implemented. when looking specifically at bowlers and batsmen, strengthening the posterior chain, core, mobility work (for bowlers), and upper body strength, mobility and core work (for batsmen) were the main focus. this is an important finding as previous research has indicated that upper body strength training, as well as core strengthening, is important for both injury prevention (particularly for the lower back) and improved performance.[3,7,8] there were no reports of lower body injury prevention exercises. this is interesting considering that hamstring injuries (together with the lower back) were the most common injuries for fast bowlers (table 4). there is extensive research showing that the strengthening and eccentric loading of the lower limb musculature (specifically the hamstrings) can reduce the risk of injury.[9] while the trainers did implement box jumps, which are both concentrically and eccentrically focused, other injury table 2. description of equipment, drills, the period of the season and the sessions per week for the different training practices type of training equipment (n) period of season (n) drills (n) sessions/ week (n) flexibility foam roller (5) r-band (5), swiss ball (2) pre-season (5) in-season (5) off-season (5) dynamic (5) static (5) pnf (5) ballistic (5) n/a speed cones (5) hurdles (5) r-bands (5) weights (5) sleds (5) pre-season (5) in-season (3) off-season (4) sprint (5) plyometrics (5) resistance (5) assistance (2) 1 (2) 2 (3) agility ladders (5) cones (4) hurdles (4) r-bands (3) slalom poles (2) pre-season (5) in-season (2) off-season (4) n/a 1 (1) 2 (3) 5 (1) plyometrics boxes (5) hurdles (5) cones (2) r-bands (1) medicine balls (1) pre-season (5) in-season (4) off-season (4) n/a 1 (1) 2 (3) 5 (1) strength dumbells (5) barbells (5) kettlebells (5) body weight (5) medicine balls (5) r-bands (4) machines (3) pre-season (5) in-season (5) off-season (5) n/a 3 (4) 4 (1) r-bands, resistance bands; n/a, not applicable; pnf, proprioceptive neuromuscular facilitation; n, number of coaches original research sajsm vol. 32 no. 1 2020 4 prevention exercises that solely load the lower limbs eccentrically (such as nordic hamstring lowers) may prevent injury through increased eccentric torque as well as the shifting of the torque joint angle curves of the hamstrings to longer muscle lengths.[9] lastly, while there was no mention of cricket-specific conditioning for fielders, the trainers did indicate that pre-habilitation exercises were implemented for shoulder injuries, which were the most prevalent for fielders and wicket-keepers respectively, a statement that previous literature supports.[10,11] all the trainers indicated that they implemented some form of flexibility, plyometric, speed and agility training practices, mainly during the pre-season period (table 2). these drills are important for injury prevention and improved performance.[11-14] furthermore, studies have shown that speed/acceleration and agility development for cricket players is important for aspects such as running between the wickets, as well as ground fielding and catching.[14] however, if the components of healthand skill-related fitness are examined it would seem as if the trainers are not covering all aspects of preparation, particularly with regards to skills such as balance, coordination and reactions which are all important aspects required by cricket players. this is also evident in the parameters that are being tested at this level. it would appear that the trainers are testing the physical characteristics based on the most common, well known and validated tests rather than those specific to the game. therefore, a specific test battery should be developed to guide programme design specific to the physical demands required in the game. in terms of the equipment used for the development of particular physical characteristics (table 2), most is nonspecialised, cheap and cost-effective. this is specifically important for those non-professional teams that are restricted due to limited budgets and do not have access to specialised equipment or facilities, as well as when players are travelling or remotely located. thus these types of characteristics can be developed anywhere without access to facilities with particular equipment that is inexpensive. however, the fact that specific exercises using the different types of equipment were not reported on is a limitation of this study, as this may have allowed a better understanding of the particular physical parameters being developed. all the trainers did some form of workload monitoring for each of the different disciplines which has been linked to reduced injury risk in bowlers.[15] it is also important to assist in identifying spikes in acute workload which can lead to overuse injuries that are becoming more prevalent in the modern day game.[6,15] how these trainers use the workload information was not explicit and may be considered a limitation of this study. effective use of the information is more important than the information itself. summary and practical applications based on the findings of the current investigation it is important to:  ensure trainers possess appropriate strength and conditioning qualifications.  conduct a specific test battery, particularly in the preseason period.  stretch before (dynamic) and after (static) a training session and match or perform mobility training to help with range of motion and flexibility.  develop physical attributes specifically flexibility, speed, agility and strength.  implement different training practices for each discipline (batsmen, bowlers and fielders/ wicket keepers).  to monitor the workload of each discipline to ensure a reduced risk of injury. conclusion the results of this study show the strength and conditioning practices of cricket trainers at a professional level, within a south african context. these can be used as a tool to educate trainers so that scientifically based strength and conditioning and injury prevention programmes can be implemented, particularly at a non-professional level where most trainers are lacking in these qualifications. furthermore, it was shown that strength and conditioning can be implemented with limited equipment and facilities and can be translated to other levels of cricket, particularly at the non-professionals level. therefore, the access to specialised facilities and equipment is not a necessity. from a practical perspective, this study demonstrates the importance of looking at most components of health and skill related fitness which can be used by the trainers at all levels. however, most of the data presented in this investigation are subjective and further studies should be conducted on larger sample groups and in other cricket playing nations. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: all authors were involved in conception, design, analysis and interpretation of data, drafting or critical revision for important intellectual content and approval of the version to be published. references 1. pote l, christie cj. strength and conditioning practices of university and high school level cricket coaches: a south african context. j strength cond res 2016; 30(12): 3464-3470. [doi: 10.1519/jsc.0000000000001432][pmid: 27075640] 2. pote l, christie cj. injury prevention strategies in cricket. strength cond j 2018;40(5):34-43. [doi: 10.1519/ssc.0000000000000409] 3. pote l, christie cj. a novel intervention programme (cricfit) for the strength and conditioning of adolescent cricket players. hum mov 2018;19(1) :34-43. [doi: /10.5114/hm.2018.73610] 4. orchard jw, james t, portus mr. injuries to elite male cricketers in australia over a 10-year period. j sci med sport 2006;9(6) :459467. [doi: 10.1016/j.jsams.2006.05.001] [pmid: 16769247] 5. ebben wp, carroll rm, simenz cj. strength and conditioning practices of national hockey league strength and conditioning coaches. j strength cond res 2004;18(4) :889-897. [doi: 10.1519/14133.1] [pmid: 15574099] 6. hulin bt, gabbett tj, blanch p, et al. spikes in acute workload original research 5 sajsm vol. 32 no. 1 2020 are associated with increased injury risk in elite cricket fast bowlers. br j sports med 2014;48(8) :708-712. [doi: 10.1136/bjsports-2013-092524] [pmid: 23962877] 7. mukandi i, turner an, scott p, et al. strength and conditioning for cricket fast bowlers. strength cond j 2014;36(6): 96-106. [doi: 10.1519/ssc.0000000000000099] 8. taliep ms, prim sk, gray j. upper body muscular strength and batting performance in cricket batsmen. j strength cond res 2010;24(12) :3484-3487. [doi: 10.1519/jsc.0b013e3181e7261b] [pmid: 21068684] 9. opar da, williams md, shield aj. hamstring strain injuries: factors that lead to injury and re-injury. sports med 2012;42(3) :209-226. [doi: 10.2165/11594800-000000000-00000] [pmid 22239734] 10. pardiwala dn, rao nn, varshney av. injuries in cricket. sports health 2018;10(3):217-222. [doi: 10.1177/1941738117732318] [pmid:28972820] 11. ranson c, gregory pl. shoulder injury in professional cricketers. phys ther sport 2008;9(1):34-39. [doi: 10.1016/j.ptsp.2007.08.001][pmid: 19083702] 12. davies g, riemann bl, manske b. current concepts of plyometric exercise. int j sports phys ther 2015;10(6):760-786. [pmid: 26618058] 13. bishop c, herridge r, turner a.. monitoring changes in power, speed, agility and endurance in elite cricketers during the off season. j strength cond res 2017;epub ahead of print. [doi: 10.1519/jsc.0000000000002077] [pmid: 286580073] 14. houghton l, dawson b, rubenson j, et al. movement patterns and physical strain during a novel, simulated cricket batting innings (batex). j sport sci 2011;29(8):801-809. [doi: 10.1080/02640414.2011.560174] pmid:215060040] 15. dennis rj, finch cf, farhart pj. is bowling workload a risk factor for injury to australian junior cricket fast bowlers? br j sports med 2005;39(11) :843-846. [doi: 10.1136/bjsm.2005.018515] [pmid: 16244195] file:///c:/10.1136/bjsports-2013-092524 file:///c:/10.1136/bjsm.2005.018515 to the editor: as a former competitive swimmer who is now involved in the health and fitness industry, i am often approached by swimmers and coaches to get my opinion on the water quality in swimming pools used for training by competitive swimmers. many swimming clubs train in heated indoor pools, mostly in a gym environment, and most of the swimmers complain of a number of symptoms such as sinus problems, itchy skin and itchy ear channels as a result of spending several hours per week exposed to chlorinated water. the scientific literature around the topic of swimming and water quality focuses on asthma and allergies caused by chlorine in swimming pools. however, none of the studies mention any normative values for chemical levels in swimming pools. the german swimming association (deutscher schwimm verband (dsv)) conforms to european standards. according to them the norm values for free chlorine levels in swimming pools should be 0.3 0.6 mg/l for an indoor swimming pool. interestingly enough, the canadian norms are quite different from the european standards. they set values for free chlorine in an indoor swimming pool at 0.8 2.0 mg/l. chlorine levels of south african swimming pools in a gym environment have been reported to be around 2.0 mg/l and fall into the higher range of the abovementioned standards. these higher chlorine levels result in a drop in the ph of the water below the recommended value (7.2 7.8), which causes additional irritation to the skin, ear, nose and eyes. i remember suffering from the above symptoms during my competitive years. while eyes can be protected by goggles, the rest of a swimmer’s body is exposed to the water. from my experience most of these symptoms are caused by elevated chlorine levels. chlorine helps to keep the water hygienic, which, understandably, is the main concern of each gym environment. however, while it doesn’t cause any harm to someone spending only 30 minutes in the water every now and then, swimmers spending several hours per week in this water often report the symptoms. i would assume that most gym environments act in the interest of their overall member base and put hygiene standards above the possible side-effects that only present for those few members spending long hours in the water. my recommendations for the competitive swimmers who spend several hours a week in the water are to firstly wash the body with soap several times straight after you get out of the water. choose a brand of soap appropriate for sensitive skin (i.e. neutral ph). this advice sounds simple, but it worked for me and for my training colleagues. it sometimes took 4 5 washes before we were able to get rid of the chlorine smell on our skin – only then we knew we had got all of it off (and yes, even wash and rinse the ear channels as far as you can!). secondly, use moisturising body lotion. one of the reasons for itchy skin is that the water dries out the skin. together with the body wash the application of moisturising lotion should at least relieve any skin symptoms. sinus problems could be relieved by wearing a nose clip during swimming. however, this is something not every swimmer feels comfortable with, as it might require a change in breathing habits. chlorine seems to be the only option for managing and ensuring a safe and hygienic pool environment. until alternative and costeffective methods are found swimmers are forced to deal with the side-effects of their training environment. lieselotte maria schoeler uct/mrc research unit for exercise science and sports medicine sports science institute of sa newlands 7700 cape town, south africa e-mail: lotte.schoeler@virginactivelifecare.co.za recommended reading aboutswimming.com: http://swimming.about.com/lr/asthma_ and_swimming/107989/3/ canadian legal information institute: http://www.canlii.org/qc/ laws/regu/q-2r.18.1.02/20070307/whole.html. document: water quality in swimming pools and other artificial pools, regulation respecting, r.q. c. q-2, r.18.1.02 dsv, deutscher schwimm verband: www.dsv.de sports medicine practitioners and sasma poorly represented at olympic and paralympic games to the editor: the year 2008 has seen the summer olympic and para lympic games being held in beijing, peoples republic of china. the south african sports medicine association (sasma) is the most representative body for sports medicine health care professionals in south africa. it is multidisciplinary and should naturally attract those who have an interest in sports medicine. it also affords membership to the international sports medicine federation (fims). i analysed the composition of the medical teams – servicing team south africa – that represented south africa at the olympic and paralympic games in 2008, and their membership status of sasma. there were, at the time of the games, 268 registered members of sasma. the table on p. 30 shows the composition of the respective teams. this simple analysis reveals that statistically, even though the total number of ‘sports’ practitioners in south africa is unknown, only 54% of sports health care practitioners at the olympic and paralympic games were sasma members. without debating the composition of the team, only doctors and physiotherapists accompanied the olympic and paralympic athletes. the teams were appointed by the south african sports confederation and olympic committee (sascoc). potential team members were invited to apply and, using a rating system, the medical team was selected. the result must be seen in light of, and in spite of, the fact that being a sasma member carries credits in the assessment of team selection, and that invitations for applicants are primarily through sasma channels. another forum of selection are recommendations letters to the editor chlorine in swimming pools sajsm vol 21 no. 1 2009 29 from national federations – usually with regard to practitioners who are involved in the federation. this is indeed a poor reflection, and we need to look critically at possible reasons and address them. some reasons could include the following and should be addressed, debated and explored: the credibility of sasma is not appreciated; ignorance as to the existence and value of sasma; sascoc does not afford adequate credibility to sasma; lack of trust or belief in sasma; and other potential factors. as a starting point, it is necessary to engage with and increase the knowledge base of national federations, sascoc, the national department of sport and recreation, provincial departments of sport, and health care professionals. it is known that many ‘sports physicians’, ‘sports physiotherapists’, and other health care providers who practise the majority of their clinical work in the field of sports medicine are not members of sasma. perhaps they feel that sasma has nothing (new) to offer them, or that they have nothing new to learn or gain by being members. they clearly do not consider that they could in fact contribute to sasma. i believe that health care providers, not only in olympic and paralympic teams, but in all sports federations and competitions, should be sought through the sasma community, hence drawing attention to the current situation. dr demitri constantinou centre for exercise science and sports medicine fifa centre of excellence school of therapeutic sciences university of the witwatersrand johannesburg e-mail: demitri.constantinou@wits.ac.za 30 sajsm vol 21 no. 1 2009 olympic paralympic medical sasma sasma members games games team members (% of total) doctors 4 2 6 4 67 physiotherapists 11 7 18 9 50 total 15 9 24 13 54 (olympics 53) (paralympics 56) case report 1 sajsm vol. 29 2017 case report: pathological fracture of the manubrium sternum of unknown aetiology j swart,1(mbchb, phd); r v p de villiers,2(mbchb, mmed (rad)); k v hosking,3(mbchb, frcs (ed ortho)) 1 division of exercise science and sports medicine, department of human biology, university of cape town, south africa 2sports science radiology, winelands radiology, sports science institute of south africa, newlands, south africa 3cape orthopaedic reconstructive unit, life orthopaedic hospital, pinelands, south africa corresponding author: j swart (jeroen.swart@uct.ac.za) case report a 26-year-old male professional football player (central defender) presented to the sports medicine clinic, sports science institute of south africa, with a five day history of sternal discomfort. prior to the onset of pain, the player had been performing tricep dip exercises, during which he suddenly heard an audible click, followed by sternal discomfort. he had been apparently elbowed during a match four months prior to his presentation at the sports medicine clinic, during which time he experienced pain over the left anterior third and fourth ribs and the left sternal border. anteroposterior and lateral chest x-rays at that time revealed no abnormality and he returned to play after two weeks without any further symptoms. he had no relevant medical history, nor was there any family medical history of relevance. his surgical history consisted of a solitary medial meniscal tear of the right knee for which he had had an arthroscopy. he had not been using any medication prior to the onset of pain. a physical examination revealed tenderness over the junction of the middle and distal third of the manubrium sternum in the midline of the body. there was no palpable mass or irregularity found. careful examination did not reveal any evidence of cervical, or axillary lymphadenopathy. there was no evidence of goitre or other thyroid enlargement. there were no abnormalities of the respiratory system. plain x-rays of the manubrium sternum identified a cortical irregularity of its anterior cortex at the area of maximal tenderness. there was no identifiable fracture line. due to the minor force involved and the long history between the previous trauma and the new onset of pain, the fracture was assumed to be pathological and further investigations were requested. ct scan a ct scan was performed (fig 1 and 2). sagittal reconstructions showed an area of lysis with a linear fracture line thought to represent a pathological fracture. mri scan a magnetic resonance imaging (mri) scan was also performed. this too demonstrated the fracture line through the manubrium sternum. there was associated bone marrow oedema, as well as an associated presternal and retrosternal soft tissue mass. the differential diagnosis included osteitis (tuberculosis or staphylococcal) or a possible tumour (lymphoma or a round cell tumour). blood investigations did not reveal any abnormalities. specifically, a complete blood count was normal, as were the erythrocyte sedimentation rate and c-reactive protein values. an incision biopsy of the fracture site and soft tissue were performed under general anaesthesia. a bone marrow biopsy from the left iliac crest was also performed intra-operatively. histology the frozen section of the biopsy tissue showed trabecular bone between which were spindled cells in keeping with fibrous connective tissue. paraffin sections of the biopsy tissue consisted of fragments of trabecular bone. granulation tissue and fibrous connective tissue were noted within the intervening bone marrow. osteoid and reactive bone were also noted. importantly, there was no evidence of lymphoma or other malignancy. the morphological features were in keeping with a healing fracture site. bone marrow aspiration the bone marrow material showed adequate hemopoiesis in a 26-year-old male professional football player presented with sternal discomfort after performing upper limb exercises. x-rays and a computed tomography (ct) scan of the manubrium sternum indicated an area of lysis with a fracture line. an mri showed bone marrow oedema as well as presternal and retrosternal soft tissue mass. an incision biopsy of the site and the soft tissue were performed under general anaesthesia. additional investigations included a bone marrow biopsy from the left iliac crest, a full blood count and c-reactive protein test, all of which were normal. the morphological features were mostly in keeping with a healing fracture site, and the investigations revealed no evidence of a tumour or structural abnormality. in bone injuries, where the level of force is not commensurate with the degree of injury or where the anatomical area and other factors in the presentation are unusual, they require careful investigation. treating physicians should actively exclude the multitude of potential causes when investigating pathological fractures. keywords: pathology, manubrium, stress fracture s afr j sports med 2017; 29:1-2. doi: 10.17159/2078-516x/2017/v29i0a3512 mailto:jeroen.swart@uct.ac.za http://dx.doi.org/10.17159/2078-516x/2017/v29i0a3512 case report sajsm vol. 29 2017 2 all three hemopoietic cell lines. there were no abnormal infiltrates present in the examined material. conclusion the investigations revealed no evidence of a tumour or underlying structural abnormality. in the final assessment, it is presumed that the patient sustained a significant bone bruise of his manubrium sternum and subsequently developed a pathological fracture. a stress fracture of the sternum can also not be excluded. rare cases of stress fractures of the sternum after upper body exercise have been reported. [1,2] at follow-up two weeks after the biopsy, the patient appeared to have improved significantly from a clinical perspective and did not have any discomfort during physical activity or heading (which previously elicited pain). he subsequently made an uneventful recovery and returned to play four weeks post presentation. non-traumatic fractures of the sternum are rare. [3-5] the above case, although ultimately benign in outcome, highlights the need for careful investigation of all bone injuries where the level of force is not commensurate with the degree of injury or where the anatomical area and other factors in the presentation are unusual. treating physicians should actively exclude the multitude of potential causes when investigating pathological fractures. references 1. hill pf, chatterji s, demello wf,et al. stress fracture of the sternum: an unusual injury? injury 1997; 28:359-361. [https:// doi.org/10.1016/s00201383(97)00016-8] 2. robertsen k, kristensen o, vejen l. manubrium sterni stress fracture: an unusual complication of non-contact sport. br j sports med 1996; 30:176177. [https:// doi.org/10.1136/bjsm.30.2.176] 3. schapira d, nachtigal a, scharf y. spontaneous fracture of the sternum simulating myocardial infarction. clin rheumatol 1995; 14:478-480. [https:// doi.org/10.1007/bf02207687] 4. aymard a, chevrot a, wybier m,et al. spontaneous fracture of the sternum. j radiol 1987; 68:593-595. [pmid: 3430442] (french) 5. swarup s, bonomally k, ansari mz. fracture of the sternum-an unusual case. eur j emerg med 1999; 6:71-72. [pmid: 10340738] fig. 1. axial ct of the sternum, showing a lytic bone lesion fracture. fig. 2. ct of the sternum. sagittal reconstruction shows pathological fracture. 1 2 sajsm 577.indd original research 20 sajsm vol. 27 no. 1 2015 background. the use of medications by football players in many populations is known to be high. data on african players are scarce. objective. to determine the magnitude of use of non-steroidal anti-inflammatory drugs (nsaids) and nutritional supplements by zimbabwean football players. methods. we conducted a cross-sectional study during the 2011/2012 premier soccer league football season. a total of 86 players responded to a self-administered questionnaire that assessed self-reported use of nsaids and nutritional supplements. results. all the participants admitted to taking nsaids, with 44% self-prescribing. nutritional supplements were taken by 56% of the respondents. of these, 21% took them on a daily basis and 40% did so without professional advice. conclusion. regular, self-prescribed use of nsaids and nutritional supplements is high among zimbabwean football players. s afr j sports med 2015;27(1):20-22. doi:10.7196/sajsm.577 use of non-steroidal anti-inflammatory drugs and nutritional supplements in zimbabwean football n s mkumbuzi,1,2 bsc (hons) (physio); f kaseke,3 msc (physio) 1 department of physiology, college of health sciences, university of zimbabwe, harare, zimbabwe 2 zimbabwe rugby union, harare, zimbabwe 3 department of rehabilitation, college of health sciences, university of zimbabwe, harare, zimbabwe corresponding author: n s mkumbuzi (nsmkumbuzi@gmail.com) athletes are usually young individuals in good health, who may use a variety of legal medications and methods to prevent/treat injuries or for competitive edge. this has led to an epidemic of drug use in sport, which is growing in complexity. [1] often though, most literature and media attention focuses on illegal drugs. [2] however, the use of drugs not banned by the world anti-doping agency should also be considered in light of the ethical and health issues that surround their improper use. studies have shown that athletes use non-steroidal anti-inflammatory drugs (nsaids) and nutritional supplements more than age-matched controls,[1] often in inappropriately high doses,[3] concomitantly and without medical advice. [4] while the major concerns of sporting associations are with the use of illegal drugs and supplements, it is imperative that the magnitude of the use of seemingly harmless drugs be investigated, both to safeguard players’ welfare and to help design preventive doping measures. data on the use of legal drugs and supplements by football players are few and far between, and on african players fewer still.[5] the objective of this study was to quantify the magnitude of the use of nsaids and nutri tional supplements by professional zimbabwean football players. methods during the latter half of the football season, registered football players from 11 of the 16 teams in the premier soccer league (psl) during the 2011/2012 football season were approached via their club management to participate in the study. questionnaires were taken to their various training stadia during training and distributed at the end of a training session for completion in the players’ own time, should they consent to participate in the study. this questionnaire was adapted for contextual validity from those validated by experts and used in previous studies.[5,6] the questionnaires were anonymous and did not contain any identification information. permission was obtained from the zimbabwe football association (zifa), and the administrative body for the psl. ethical approval to conduct this study was obtained from the institutional review board at the university of zimbabwe, college of health sciences, protocol number jrec/150/11. continuous variables are presented as means and standard deviations (sds), and shown as frequencies and percentages. results of the 400 questionnaires given out, 86 (22%) were completed and returned. all the participants in this study were male, with a mean (sd) age of 23 (2) years (range 17 30). the majority were single (51%) and had a secondary school education (table 1). a large proportion of the players (83%) had been playing football for >6 years at the time of data collection (table 2). more than half of the players trained for ~3 5 hours/day and for 3 5 days/week (52% and 87%, respectively), and this training was related to league games and championship commitments. over half of the respondents (56%) admitted to current use of nutritional supplements, with less than half of these (21%) taking them daily (table 3). vitamin supplements were the major form of supplementation taken (20%), closely followed by mineral supplements (17%). the main reason for taking these supplements is unknown, as almost half of the respondents (43%) did not state the reason. of those that did, they took dietary supplements to build muscle bulk (15%), maintain general health (14%) and for other reasons such as luck. most of these supplements were taken without expert advice (40%). medical doctors were the main source of information and advice on nutritional supplements (27%). only one respondent received advice from a nutritionist before taking nutritional supplements, while a number of players sought advice from a traditional healer or other professionals (15%). sajsm vol. 27 no. 1 2015 21 all participants admitted to taking at least one nsaid at the time of the study (table 4). most of these nsaids were self-prescribed (44%). medical doctors were consulted less for advice and information on nsaids than they were consulted for advice on nutritional supplements (4% v. 2%, respectively). discussion the response rate was 22%, which is typical in this type of population, as football players are difficult to enrol in a large cohort unless at major tournaments. additionally, the study sought information on a somewhat sensitive subject and athletes are generally reluctant to discuss their personal drug habits. [6] the proportion of missing information in our survey was also a testament to this observation (tables 1 4), as is the fact that this response rate is marginally less than that obtained by other authors on the same subject, who interviewed team physicians instead of the players.[2] however, huang et al.[7] obtained response rates of 94% and 98% in athlete interviews during the atlanta and sydney olympic games, respectively, while taioli[8] obtained 95% in a survey of italian football players. overall, the response rate in the present study, though low, was considered satisfactory because the results obtained from this study were similar to those from previous studies on the same subject, and the conclusions drawn from these results reflect the same trends as those observed by other authors globally.[2,6-8] this is a good indication that a representative sample was obtained in this study. our survey indicated a very high intake of nsaids, with 100% of the respondents reporting intake of an nsaid at the time of data collection. these results are similar to those obtained by other authors in similar table 1. demographic data, n (%) age (years) 15 19 14 (16) 20 24 42 (49) 25 29 27 (32) marital status married/cohabiting 37 (43) divorced/widowed 1 (1) single 44 (51) educational status primary 3 (4) secondary 74 (86) tertiary 7 (8) position of play goalkeeper 16 (19) defender 21 (24) midfielder 30 (35) striker 17 (20) table 2. length of football career and duration of training sessions, n (%) length of football career (years) ≤2 7 (8) 3 5 3 (3) ≥6 72 (83) number of weekly training sessions (days/week) ≤2 0 (0) 3 5 75 (87) ≥6 7 (8) duration of daily training sessions (hours) 0 2 2 (2) 3 5 45 (52) ≥6 37 (43) table 3. use of nutritional supplements, n (%) current use of nutritional supplements (n=86) yes 48 (56) no 38 (44) types of nutritional supplements (n=48) herbal 2 (4) mineral 8 (17) protein powders 4 (9) vitamin 10 (20) multiple 3 (6) frequency of use of nutritional supplements (n=48) never 20 (41) daily 10 (21) weekly 3 (6) twice/week 4 (9) monthly 2 (5) not sure 9 (20) reasons for use of nutritional supplements (n=48) no response 21 (43) to boost immunity 2 (5) to enhance performance 3 (7) to prevent injuries 1 (4) to augment diet 1 (1) to build muscle bulk 7 (15) to maintain general health 7 (14) other (e.g. luck, improved power) 6 (12) sources of advice on use of nutritional supplements (n=48) self 19 (40) physiotherapist 2 (4) medical doctor 13 (27) nutritionist/dietician 1 (1) fitness trainer 2 (4) other (traditional healer, family member, fellow player, coach) 7 (15) 22 sajsm vol. 27 no. 1 2015 cohorts. holmes et al.[3] demonstrated a 96% consumption rate in collegiate football players, 93% of italian footballers were found to be taking nsaids[7] and 100% of gymnasts at the sydney 2000 olympic games were found to be taking nsaids.[8] in these studies, 50%, 22% and 100%, respectively, of these athletes took nsaids daily, compared with 12% in the present study; however, our results represent a higher nsaid intake than observed during various fédération internationale de football association (fifa) world cup tournaments, where about 40% of football players used nsaids.[9] at these tournaments, however, the consumption of nsaids far outweighed the injury rate. this liberal use of nsaids raises misgivings of whether they are being used solely for therapeutic purposes or whether athletes have discovered their ergogenic aid. this theory is supported by data from other studies, which show that athletes are using nsaids for ‘prophylactic pain management’. [9] some use nsaids for treatment of injuries, probably because they do not take time off to rehabilitate minor injuries.[1,10] the latter may also explain the high prevalence of use of nsaids in our sample, as the majority of the participants had intense training schedules. this ample use of nsaids, often without medical advice, reflects that footballers may be unaware of the cumulative adverse effects of nsaids on the various body systems,[10] and may have developed these drug habits from early adolescence, considering that the majority of these participants have been playing football from an early age. in this study, over half of the football players (56%) took nutritional supplements. vitamin supplements represented the majority of the supplements taken (20%) and were taken daily by ~1/5 players. this is a lot less than the 82% obtained by taioli[8] among italian football players, and that observed by waddington et al.[6] in english football players (58%). vitamins were also the most common form of supplementation (41%) taken by football players during the 2006 fifa world cup.[2] in comparison, across sporting disciplines, the use of nutritional supplements is generally upward of 60%.[2,8,9] it is noteworthy, though, that for reasons unknown, african athletes report lower nutritional supplement use than their euro pean and american counterparts, especially in ball sports such as football.[9] nutritional supplements are not necessary in athletes who are generally healthy by all standards. however, aggressive advertising and endorsements by supple ment manufacturers have led to a high use of supplements in highly active individuals, as they purport to aid recovery and assist with altering body composition favourably. [7] data to support these assertions are equivocal.[11] this uncertainty is even more pertinent in light of the fact that 40% of our participants were found to be taking dietary supplements at their own discretion and without professional advice. this trend exists in athletes from other populations, who have a tendency not to consult club medical personnel before taking supplementation. [6,10] this trend to self-medicate is worrisome, especially to the 9% of the participants who reported taking protein powders that may contain creatine. creatine and other amino acid preparations, if improperly dosed, may have deleterious effects on vital organs.[6] in addition to the harmful effects that these supplements may have on the body, the risk of crosscontamination with banned substances during manufacture exists, as the manufacture of supplements is not strictly regulated. this, plus inadequate product labelling, may lead to an inadvertent positive dope test.[12] interestingly, a considerable proportion of our respondents (15%) consulted a traditional healer for supplements, presumably herbal. this is not surprising in the african setting, where the game of football is fraught with rituals, and the use of juju (traditional medicine) for luck and victory is rife.[13] however, as the active ingredients of most of these preparations are unknown, the possibility of accidental ingestion of a banned substance also exists. study limitations the data were collected at a single time point, from the footballers’ perspective. drug use frequency may fluctuate during the season and is subject to social and recall bias. future studies may explore this further over a whole season more objectively, e.g. using blood tests. conclusion the use of nsaids and nutritional supplements was high in these zimbabwean footballers, but lower than in other similar populations. the major concern is that these medications are taken without professional advice or supervision. in addition to providing information on illicit drugs, information on the effects of permitted drugs such as nsaids should be disseminated to athletes, as should the risk of unintentional doping with unchecked use of nutritional supplements. references 1. alaranta a, alaranta h, helenius i. use of prescription drugs in athletes. sports med 2008;38(6):449-463. [http://10.2165/00007256-200838060-00002] 2. tscholl p, junge a, dvorak j. the use of medication and nutritional supplements during fifa world cups 2002 and 2006. br j sports med 2008;42(9):725-730. [http://10.1136/bjsm.2007.045187] 3. holmes n, cronholm pf, duffy aj iii, et al. nonsteroidal anti-inflammatory drug use in collegiate football players. clin j sport med 2013;23(4):283-286. [http://10.1097/ jsm.0b013e318286d0fa] 4. warner dc, schnepf g, barrett ms, et al. prevalence, attitudes, and behaviors related to the use of nonsteroidal anti-inflammatory drugs (nsaids) in student athletes. j adolesc health 2002;30(3):150-153. [http://10.1016/s1054-139x(01)00325-1] 5. ama pfm, betnga b, ama moor vj, et al. football and doping: study of african amateur footballers. br j sports med 2003;37(4):307-310. [http://10.1136/bjsm.37.4.307] 6. waddington i, malcolm d, roderick m, et al. drug use in english professional football. br j sports med 2005;39(4):e18. [http://10.1136/bjsm.2004.012468] 7. huang s, johnson k, pipe al. the use of dietary supplements and medications by canadian athletes at the atlanta and sydney olympic games. clin j sport med 2006;16(1):27-33. 8. taioli e. use of permitted drugs in italian professional soccer players. br j sports med 2007;41(7):439-441. [http://10.1136/bjsm.2006.034405] 9. tscholl p, alonso jm, dollé g, junge a, dvorak j. the use of drugs and nutritional supplements in top-level track and field athletes. am j sports med 2009;38:1. [h ttp://10.1177/0363546509344071] 10. gorski t, cadore el, pinto ss, et al. use of nsaids in tri-athletes: prevalence, level of awareness and reasons for use. br j sports med 2011;45(2):85-90. [http://10.1136/ bjsm.2009.062166] 11. hespel p, maughan rj, greenhaff pl. dietar y supplements for football. j sports sci 2006;24(7):749761. [http://dx.doi.org/10.1080/02640410500482974] 12. van der merwe pj, grobbelaar e. unintentional doping through the use of contaminated nutritional supplements. s afr med j 2005;95(7):510-511. 13. c havundu ka gl. juju and dr ugs in sp or ts: myth or reality? sports, juju, and human factor development 2006;3:74. table 4. use of nsaids (n=86), n (%) frequency of use of nsaids never 0 (0) daily 10 (12) weekly 9 (11) twice/week 0 (0) monthly 5 (6) rarely 37 (43) sources of information and advice on nsaids self 38 (44) physiotherapist 15 (17) fitness trainer 17 (20) medical doctor 3 (4) fellow player 8 (9) other 5 (6) who could have predicted at the start of 2009 that sex verification in sport would have received so much front page news all over the world? as with all matters complicated, following discussion and an exchange of views, there are always more questions than answers. in particular, when biological facts are made murky by cultural and sociological influences the number of unanswered questions increase exponentially. the risk for a polarisation of views is high. an attempt has been made to answer some of these questions in the review ‘the science and management of sex verification in sport’ by tucker and collins, published in this edition (p. 147). this review systematically provides some background and historical context to sex verification in sport and exposes some of the biological/ medical nuances. the iaaf consensus statement and the canadian academy of sports medicine recommendations on sex verification are presented. the different foci of these statements confirm the difficulty in reaching universal consensus. clearly, there is a need to have specific guidelines for the south african context to provide a framework of reference for any similar cases in the future. such guidelines will surely prevent a repeat of the debacle that occurred when athletics south africa (asa) mismanaged the situation that transpired at the world championships in berlin in august 2009. in accordance, the department of sport has commissioned a document that will provide guidelines for managing sex verification in the south african context. the process of compiling the guidelines is being coordinated by dr ramagole and the final document will be published in this journal in 2010. perhaps these guidelines will be the ‘silver lining’, resulting from the unfortunate series of events involving asa, and will ensure that we avoid public scrutiny and subsequent humiliation of anyone with intersex characteristics in the future. the term of the editorial board consisting of professors mars, coopoo, myburgh, noakes, rogers and vaughan comes to an end with this edition of the journal. this editorial board has served for 11 years and their combined experience and wisdom has been a major factor in the growth of the journal. we thank them sincerely and trust that they will continue to support the journal in the capacity of either an author or a reviewer! in 2010 there will be some exciting changes in the journal. the online version of the journal (www.sajsm.org.za) will be promoted locally and internationally. in 2009 we had visitors to the website from 45 countries – as the website is promoted more widely we expect this to increase substantially. next year we will also have a section that will allow readers to earn cpd points by completing an online questionnaire on the contents of papers published in that issue. also, the president of sasma has negotiated a deal with the british journal of sports medicine that will allow us to publish selected articles from that journal. he has organised prize money for the best paper published in the journal in 2010 – more details about this will follow early next year. in short, the journal has exciting times ahead! this will coincide with the world focus on south africa before and during the fifa world cup – what an opportune time to show the country and the rest of the world how sports medicine has evolved to be inextricably linked to high-performance sport. mike lambert editor-in-chief a silver lining … a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial 146 sajsm vol 21 no. 4 2009 sajsm vol 18 no.1 2006 3 while i was training in the gym last week i counted 23 out of the 49 people in the gym at that time with earphones and music devices. the people using these devices ranged from young, bodyconscious teenagers, to older folk, old enough to be their grand parents. whatever they were listening to remained a mystery but a safe bet would be anything from classical to golden oldies to hip-hop. there is no doubt that this new exercise-associated behaviour is here to stay. there were a few false starts in the 1980s and 1990s with appearance of the popular sony walkmans, but they were too bulky and were not widely used during exercise. furthermore, it was mostly the younger generation that used these music players in public. the development of ipods in 2001 marked the beginning of the music and exercise ‘fashion’. fashion is probably an inappropriate term because ipods have stood the test of time and outlasted many other exercise-associated fads. since the development of the first batch of ipods,110 million have been sold worldwide and there are probably double the number of people using portable media players, certainly if the inexpensive, less sophisticated brands of mp3 players and cell phone/mp players are also considered in the estimate. new behaviour leads to new questions and new questions lead to research. some scientists have already studied the effects of music while exercising. a quick perusal of the literature shows that over 150 studies have been conducted in the last 2 years. the message these studies convey is generally positive, with many studies showing that there may certainly be advantages in listening to music while exercising, particularly where there is a high risk of poor compliance. studies have also shown that older people with dementia have improved cognitive function if they listen to music while exercising. furthermore, many of the problems associated with alzheimer’s disease can sometimes be delayed, retarded, or even reversed with proper exercise. 1 a body of research shows that music with activity brings about the greatest degree of responsiveness in these patients. it might not only be music that people listen to while exercising. as more electronic books become available it is conceivable that many people will choose to listen to their favourite novel while they pedal away the calories. indeed, there is probably a place in the market for the production of study notes which can be listened to while exercising. if the research on older patients is considered, a case can be made that listening to study notes while exercising might prove to be an efficient way to retain information, even a study enhancer? not all the studies about music during exercise are supportive – fligor and cox studied the sound levels generated by a range of headphones and found that certain types of earphones are safer than others. 2 the study showed that the average person listens to music at the same noise level generated by a petrol lawnmower. this behaviour can have long-term effects that impair hearing. they recommended that for ear health one should invest in earphones that block out background noise, set the volume to a comfortable level in a quiet environment, and limit the duration to about 60 minutes. on another note, a fascinating article has just been published in nature, showing that 20% of scientists polled admitted to using performance-enhancing prescription drugs. 3 the 1 400 respondents were from 60 countries and were asked about their use of 3 drugs: methylphenidate (ritalin), a stimulant normally used to treat attention-deficit hyperactivity disorder, modafinil (provigil), prescribed to treat sleep disorders, and beta blockers. ritalin was the most well-used drug (62% of users) followed by modafinil (44%) and beta blockers (15%). nearly 70% of the respondents said they would be willing to risk mild side-effects to be able to ‘boost your brain power’ by taking cognitive-enhancing drugs. given these results, if a random sample of academics underwent the same drug test that athletes have to undergo, about 20% would be tested positive – this prevalence ranks high among the sports renowned for competitors who use drugs to boost performance (e.g. cycling, body building). as a community, scientists need to drop the ‘holier than thou attitude’ when an athlete has a positive drug test! could this mean that scientists have to have drug tests before submitting a paper for publication, or before a public presentation? makes one think! mike lambert editor-in-chief 1. cevasco am, grant re. comparison of different methods for eliciting exercise-to-music for clients with alzheimer’s disease. j music ther 2003; 40(1): 41-56. 2. fligor bj, cox lc. output levels of commercially available portable compact disc players and the potential risk to hearing. ear hear 2004; 25(6): 513-27. 3. maher b. poll results: look who’s doping. nature 2008; 452: 674-75. tune in while you tune out a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial sajsm vol 20 no. 1 2008 3 editorial tune in while.indd 3 4/23/08 11:29:42 am original research 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license musculoskeletal pain in south african wheelchair basketball players of different point classifications i s m mateus, 1 mtech chiropractic ; j d pillay, 2 phd 1 department of chiropractic, faculty of health sciences, durban university of technology, south africa 2 department of basic medical sciences, faculty of health sciences, durban university of technology, south africa corresponding author: j d pillay (pillayjd@dut.ac.za) physical activity through sport is well recognised as an effective means of obtaining both physical and emotional health, as well as social well-being.[1] sport and recreation in general have an even greater impact on individuals with impairments who, partly due to the nature of their impairment, may be predisposed to leading sedentary lifestyles. apart from the physical health and fitness benefits of sport, participation in either recreation or competitive sport promotes improved self-esteem and provides a sense of inclusion, thereby empowering participating individuals with impairments.[2] participation in sporting activities for individuals with impairments, especially wheelchair users, has increased exponentially over the past few decades despite the challenges faced by these athletes.[3] developments in para sport is evident in the increase in the number of participants. in 1948, 16 participants competed in the first stoke mandeville games and number quickly grew to over 4000 athletes competing in the paralympic games in london in 2012 [4] and in rio in 2016 respectively. [5] there are a variety of wheelchair sports such as wheelchair tennis, road racing, track racing, wheelchair rugby and wheelchair basketball. wheelchair basketball is a fast-paced, five players per side sport. high intensity propulsion and manoeuvring are key characteristics of the sport, together with quick passing, rebounding and reaching overhead for shooting.[6,7] prior to participation, players are classified according to a point score system used to rank a player’s functional ability to execute movements in basketball. ranking is largely dependent on their level of disability. this classification scale ranks players using a 1.0 to 4.5point range (eight classifications at 0.5 point intervals). lower (1.0-2.5) point players are typically players that are wheelchair bound due to a spinal cord injury, spina bifida or other birth conditions/defects resulting in paralysis or the inability to use their lower limbs. higher (3.0-4.5) point players include players with amputations, mild poliomyelitis or birth defects resulting in fairly significant leg length inequalities. these players may not necessarily require the use of a wheelchair for activities of daily living, but are required to use a wheelchair during competitive play. the five players on court at one time must not exceed 14 points as a team.[8] recent studies have shown that athletes with impairments are more prone towards experiencing musculoskeletal pain (msp) and injury than able-bodied athletes.[9] however, a more recent study by derman et al. [10] established that there is a higher incidence of upper limb injuries in para athletes as opposed to able-bodied athletes. furthermore, the different wheelchair sports and the type of impairment of athletes may predispose them to varied incidences and types of msp and injury.[9] some examples include lateral epicondylitis in wheelchair racers due to repetitive and forceful elbow extension, pronation and wrist flexion. another example is de quervain’s tenosynovitis in athletes that participate in racquet and throwing sports.[11] in italy, bernardi et al.[12] conducted a study on muscle pain in athletes with locomotor disability and found that 51% of wheelchair athletes reported muscle pain and that 59% of them were wheelchair basketball players. due to the constant use of the upper extremity for wheelchair propulsion, wheelchair basketball players have an increased risk of pain and overuse injuries in this extremity, particularly of the shoulder.[13] this is further exacerbated by overhead activities (for example, shooting or rebounding after a failed shot), ball handling, background: during recent years, wheelchair basketball has gained worldwide popularity. several studies have demonstrated a high prevalence of injuries amongst wheelchair basketball players. few studies, however, have investigated the prevalence of musculoskeletal pain in the context of different point classifications – an integral part of wheelchair sport. objective: the aim of this study was to determine the prevalence of musculoskeletal pain in wheelchair basketball players of different point classifications in south africa and to provide information on patterns of pain distribution in relation to point classification. methods: a questionnaire was completed by 48 wheelchair basketball players participating in the supersport league games of south africa with point classifications ranging from 1.0 to 4.5. the results were used to determine the patterns of musculoskeletal pain distribution in relation to the different point classifications. results: forty-three completed questionnaires were analysed. the prevalence of total musculoskeletal pain was 58% (n=25). shoulder pain presented the highest overall prevalence, regardless of point classification (n=23; 92% since the start of players’ wheelchair basketball careers and n=19; 76% over the last 12 months). it was found that lower point classification (1.0-2.5) players commonly experienced arm pain since the start of their wheelchair basketball careers (ƞ=0.358), as well as specifically over the last 12 months (ƞ=0.319), unlike higher point classification (3.0-4.5) players. discussion: the study contextualises the prevalence of musculoskeletal pain to overall point classification in wheelchair basketball. such data are important in the formation of injury prevention strategies, as athletes with impairments are predisposed to different types of musculoskeletal pain based on point classification. keywords: physical activity, athletes with impairments, prevalence, injury prevention s afr j sports med 2019;31:1-5. doi: 10.17159/2078-516x/2019/v31i1a6067 mailto:pillayjd@dut.ac.za http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6067 https://orcid.org/0000-0001-8502-8878 original research sajsm vol. 31 no. 1 2019 2 wheelchair manoeuvring and player pursuit.[13] in addition, the seated position of these athletes, especially for those with spinal cord injuries, involves the pelvis being tilted posteriorly, with a forward head posture and an increased thoracic kyphosis.[14] this causes the shoulder girdle to be displaced anteriorly, placing an increased strain on the neck and upper back, with decreased scapula-thoracic function.[14] furthermore, insufficient strengthening programmes of the stabilising muscles of the scapula and rotator cuff muscles may cause muscle imbalances in these athletes.[9,14] current research on msp and other injuries in wheelchair basketball athletes primarily focusses on shoulder pain.[14] other regions of pain, however, include the wrist, neck and lower back due to high intensity movements in wheelchair basketball.[11] furthermore, msp can be further affected by the type of disability with which the player presents[9] and for which the risk for other injuries amongst the different point classifications may vary. the aim of this study was therefore to determine the prevalence and patterns of msp distribution in relation to point classification in a cohort of athletes participating in wheelchair basketball. methods participants the study population was comprised of 48 wheelchair basketball players, participating in the supersport league games of south africa, with point classifications ranging from 1.0 to 4.5. procedure a questionnaire, adapted from a study by curtis and black[14] on female wheelchair basketball players, was used as the data collection tool in this study. the questionnaire included demographic data and disability characteristics, wheelchair basketball and activity levels, as well as data pertaining to the prevalence of msp and its impact on wheelchair basketball and/or activities of daily living. for the purpose of this study, msp was defined as an instance or multiple instances of pain in the musculoskeletal system. no distinction was made between acute, subacute or chronic pain, but rather msp shown since the start of these players’ wheelchair basketball careers, and specifically in the last 12 months. the questionnaire was critically appraised through a focus group discussion comprising six para sport participants and specialists in questionnaire design. it was subsequently sent to a pilot group for administration. the focus group and pilot study was employed as an additional step to ensure that the measurement instrument would obtain the necessary data required to satisfy the objectives of the study. from the pilot study, a cronbach’s alpha was obtained to determine the consistency of scoring. the result of the reliability coefficient for the entire questionnaire (comprised of 83 questions) generated a score of 0.73. a coefficient of 0.70 or greater is considered as an acceptable score for a standardised instrument.[15] permission to administer the questionnaire to the league players was obtained from the chief executive officer/secretary general of wheelchair basketball south africa and the relevant management staff. ethical approval was granted by the durban university of technology institutional research ethics committee (clearance number irec 059/15). a letter of information was provided to all potential participants at the 2015 supersport league games. inclusion criteria incorporated signed informed consent by those participants who were wheelchair basketball players that had competed in the 2015 supersport league games, were classified on a scale from 1.0 to 4.5 (based on international classification guidelines), who were a minimum of eighteen years of age and south african citizens. the researcher attended the supersport league games where the questionnaires were explained and subsequently given to all the players present. these questionnaires were completed anonymously and placed in a sealed ballot box. statistical analysis questionnaire data were analysed using the spss statistical package, version 23.0. inferential techniques included the use of correlations in the form of cross tabulations and eta scores, as these are typically used to present comparisons when one variable is nominal and the other is a scale measure (number). in this study, the association between point classification (the nominal variable) and pain prevalence (the scale measure) was investigated. eta scores of 0.10 and less were interpreted to be a small/smaller than the typical strength of a relationship, 0.24 is a medium/typical strength, 0.37 is a large/larger than typical strength, and 0.45 is interpreted as a much larger than the typical strength of a relationship.[16] results of the 48 wheelchair basketball players participating in the supersport league games of south africa, 43 participants completed the questionnaire. almost half of the participants (n=20; 59%) were wheelchair users and most of them (n=41, 95%) had played wheelchair basketball for more than five years. of the 43 participants, 25 (58%) had experienced msp in the last 12 months. of the 25 participants who had experienced msp, 68% (n=17) attributed it to instances related to wheelchair basketball either during training or during a match. furthermore, 80% of these participants (n=20) reported that msp affected at least one aspect of their lives negatively, such as wheelchair basketball participation and performance, as well as work performance. further analysis of the prevalence of msp showed the results were stratified based on the point classification of players. there were seven 1.0, seven 2.0 and seven 3.0 point players. the different point players were therefore evenly spread from 1.0 to 4.5 points. table 1 illustrates the association between point classification and the prevalence of msp since playing wheelchair basketball, whilst table 2 illustrates the same association only over the last 12 months. arm pain was markedly prevalent in both instances but only in lower point players. there is a clear indication in table 1 that the majority of the 35 players who had experienced msp, encountered shoulder pain (n=23; 92%) since playing wheelchair basketball. furthermore, original research 3 sajsm vol. 31 no. 1 2019 the distribution of players experiencing shoulder pain does not appear to be limited to a specific point classification category. the eta score for arm pain (ƞ=0.358) showed a larger than typical relationship (an association) between point classification and the prevalence of arm pain since playing wheelchair basketball. this relationship was seen in table 1 under the frequency distribution, which clearly showed that arm pain was more evident in the lower point players (1.0-2.5 point players). furthermore it was noted that lower point players had the highest prevalence of msp experiencing 39 out of 61 (64%) recorded instances of msp. there were no significant relationships between point classification and the prevalence of neck, back and lower extremity pain since playing wheelchair basketball, as displayed in table 1 under the frequency distribution. it is evident from table 2 that the majority of the 25 players that experienced msp, experienced shoulder pain (n=19; 76%) regardless of the point classification within the last 12 months. the eta score showed a greater than typical relationship but less than large relationship between point classification and the prevalence of arm pain in the last 12 months (ƞ=0.319). in table 2, this relationship is shown where arm pain was experienced by two 1.0 point players. again, it was noted that lower point players had the highest prevalence of msp, with lower point players experiencing 30 out of 47 instances of msp (64%). this table shows that there was no significant relationship between point classification and the prevalence of neck, back and lower extremity pain in the last 12 months. table 1. . the association between point classification and the prevalence of musculoskeletal pain since playing wheelchair basketball point classification (n=25) region 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 total eta score (ƞ) arm 3 0 0 1 0 0 0 0 4 0.358* hand and wrist 1 2 1 0 0 0 1 0 5 0.211 shoulder 4 1 3 3 0 4 5 3 23 0.200 thigh 0 0 2 0 0 0 0 0 2 0.128 foot and ankle 0 0 2 0 0 0 0 0 2 0.128 hip 0 0 1 0 0 0 0 0 1 0.090 leg 0 0 1 0 0 0 0 0 1 0.090 elbow 1 1 0 2 0 0 0 1 5 0.086 low back 2 0 1 1 2 1 1 0 8 0.072 knee 0 0 1 0 0 0 1 0 2 0.062 upper back 1 0 1 0 1 0 1 0 4 0.048 neck 0 1 1 1 0 0 0 1 4 0.014 total 12 5 14 8 3 5 9 5 61 data are expressed as number of participants in each classification. * indicates strong relationship (larger than typical relationship) based on eta score >0.24. table 2. . the association between point classification and the prevalence of musculoskeletal pain in the last 12 months point classification (n=25) region 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 total eta score (ƞ) arm 2 0 0 0 0 0 0 0 2 0.319* low back 2 0 0 2 1 1 0 0 6 0.147 thigh 0 0 2 0 0 0 0 0 2 0.128 foot and ankle 0 0 2 0 0 0 0 0 2 0.128 hip 0 0 1 0 0 0 0 0 1 0.090 leg 0 0 1 0 0 0 0 0 1 0.090 hand and wrist 0 0 2 1 1 0 0 0 4 0.083 neck 0 1 0 0 0 0 0 1 2 0.062 elbow 1 0 0 0 1 0 0 1 3 0.037 upper back 1 0 0 0 0 0 1 0 2 0.033 shoulder 4 1 3 2 0 4 4 1 19 0.008 knee 0 0 2 0 0 0 1 0 3 0.002 total 10 2 13 5 3 5 6 3 47 data are expressed as number of participants in each classification. * indicates strong relationship (larger than typical relationship) based on eta score >0.24. original research sajsm vol. 31 no. 1 2019 4 discussion there was an evident association between the prevalence of arm pain and point classification. lower (1.0-2.5) point players experienced arm pain more frequently than higher (3.0-4.5) point players since the start of their wheelchair basketball careers. furthermore, hand and wrist pain was experienced more frequently by lower (1.0-2.5) point players (tables 1 and 2 respectively). there was no association evident between the prevalence of neck, back, shoulder and lower extremity pain and point classification. shoulder pain shoulder pain occurred in 23 participants (54%) since the start of their wheelchair basketball careers and was evenly distributed between lower point players (n=11) and higher point players (n=12). this finding is similar to that of the study by yildirim et al[13] where shoulder pain was found to be prevalent in 60% of lower point players and 58% of higher point players (p>0.05). lower point players, as opposed to higher point players, generally use wheelchairs for activities of daily living, in addition to during training and matches, and therefore have excessive strain imposed on their upper extremities, particularly the shoulders.[13] contrary to this, higher point players assume more ball handling roles due to greater control of their trunks and are therefore involved more in shooting from further distances, rebounding and passing.[13] arm pain arm pain occurred in four (9.3%) participants and was experienced more frequently by lower point players than by higher point players. this could be due to the position that lower point players mostly rely on the use of wheelchairs for mobility, thereby causing the upper limbs to bear the weight and remain continuously in use for propulsion. hand and wrist pain it was noted that hand and wrist pain occurred more predominantly in lower point players (n=4) than in higher point players (n=1). studies have shown that the symptoms of carpal tunnel syndrome occur in 52-100% of wheelchair users,[17] and activities involving wrist extension, such as transferring, propulsion, shooting and rebounding, may aggravate these symptoms resulting in hand and wrist pain.[6] for example, goosey-tolfrey et al.[6] found that different point players demonstrated altered shooting strategies. this could be a potential cause of the hand and wrist pain experienced, as this type of pain occurred more frequently in lower point players than in higher point players. in this study, 68% of players reported that the pain was due to an incident during the sport, which indicates a need for a modification of training regimes and/or positioning of the various body parts to reduce pain and injury. in order to implement the most effective preventative measures, further studies that investigate the exact cause of each player’s pain are necessary. such studies may require the use of threedimensional kinematic data, in addition to pain prevalence data related to point classification. to illustrate this, gooseytolfrey et al.[6] obtained three-dimensional kinematic data from 15 male wheelchair basketball players. these players were grouped into a lower point (2.0-2.5) group and a higher point (4.0-4.5) group. although this study did not investigate the prevalence of pain, the study revealed that lower point players generated greater angular velocity of the wrist at release of the free throw, whilst higher point players generated greater shoulder flexion angular velocity at the release of the free throw. their findings concluded that different point players rely on different kinematic strategies which could be the basis of the prevalence of pain amongst players of different point classifications. pain in the lower extremity although not as frequent as msp in the upper extremity, it must be noted that lower point players also experienced msp in the lower extremity, as indicated in table 1 and table 2 respectively. this could be due to the high intensity and fastpaced nature of the sport, [6] which may result in falls. it is important therefore for both coaches and practitioners working with sports teams to identify and address biomechanical errors or deficiencies among the athletes with different impairments to ensure a full recovery or prevent injury.[11] strengths of the study this study highlights the difference in msp patterns among players of different point classifications, an integral part of wheelchair sport which has not been considered in most other studies on wheelchair sport. furthermore, to these authors knowledge, this study is the first in the south african context to consider msp related to point classification in wheelchair sport. limitations and recommendations the study sample was small as it focused on south african wheelchair basketball players who participated in the supersport league games. furthermore, recruitment at the event limited the sample to elite players only, consequently resulting in recruitment bias. future studies should include a wider range of players at different levels of performance. while this study has used msp as a proxy for tissue damage, the authors realise that that this is not always the case. to be able to evaluate whether tissue damage or injury occurs in the presence of pain a methodology which includes the reporting of pain and a physical assessment should be considered. furthermore, future studies should include a more detailed profile of the msp experienced by wheelchair basketball athletes, including more in-depth questions around the incidence, severity, aetiology and mechanism of injury and pain. conclusion this study highlights the prevalence of msp in wheelchair basketball athletes. due to the increasing growth of wheelchair basketball, further research is necessary to strengthen these findings on msp and injury in the context of the different point classifications, with particular reference to preventative original research 5 sajsm vol. 31 no. 1 2019 strategies and their evaluation. in so doing, structured guidelines for reducing or preventing msp in this group of athletes can be formulated and subsequently evaluated. conflict of interest: the authors declare that they have no conflict of interest. acknowledgements: the authors gratefully acknowledge the participants of this study and the statistical assistance of mr d singh. author contributions: both authors have made substantial intellectual contributions to this paper. in addition, i s m mateus was responsible for the acquisition of data. references 1. wilson pe, clayton gh. sports and disability. pm r 2010; 2(3):s46-s54. doi: 10.1016/j.pmrj.2010.02.002. 2. wilhite b, shank j. in praise of sport: promoting sport participation as a mechanism of health among persons with a disability. disabil health j 2009; 2(3):116-127. doi: 10.1016/j.dhjo.2009.01.002. 3. klenck c, gebke k. practical management: common medical problems in disabled athletes. clin j sport med 2007; 17(1):5560. doi: 10.1097/jsm 0b013e.3180302587. 4. webborn n, emery c. descriptive epidemiology of paralympic sports injuries. pm r 2014; 6(8 suppl):s18-s22. doi: 10.1016/j.pmrj.2014.06.003. 5. rio paralympic games 2016. available at: https://www.paralympic.org/rio-2016. accessed april 11, 2019. 6. goosey-tolfrey v, butterworth d, morriss c. free throw shooting technique of male wheelchair basketball players. adapt phys activ q 2002; 19(2):238-250. doi: 10.1123/apaq.19.2.238. 7. curtis ka, drysdale ga, lanza rd, et al. shoulder pain in wheelchair users with tetraplegia and paraplegia. arch phys med rehabil 1999; 80(4):453-457. pmid: 1026610. 8. international wheelchair basketball federation. official wheelchair basketball rules 2014. january 1, 2016. available at https://iwbf.org/wp-content/uploads/2016/08/ 2014_iw bf rules_v2.pdf. accessed august 10, 2017. 9. dec kl, sparrow kj, mckeag db. the physically-challenged athlete. sports med 2000; 29(4):245-258. doi: 10.2165/00007256200029040-00003. 10. derman w, schwellnus m, jordaan e, et al. illness and injury in athletes during the competition period at the london 2012 paralympic games: development and implementation of a webbased surveillance system (web-iiss) for team medical staff. br j sports med 2013; 47(7):420-425. doi: 10.1136/bjsports-2013092375. 11. goosey-tolfrey v. supporting the paralympic athlete: focus on wheeled sports. disabil rehabil 2010; 32(26):2237-2243. doi: 10.3109/09638288.2010.491577. 12. bernardi m, castellano v, ferrara ms, et al. muscle pain in athletes with locomotor disability. med sci sports exerc 2003; 35(2):199-206. doi: 10.1249/01.mss.0000048635.83126.d4. 13. yildirim nu, comert e, ozengin n. shoulder pain: a comparison of wheelchair basketball players with trunk control and without trunk control. j back musculoskelet rehabil 2010; 23(2):55-61. doi: 10.3233/bmr-2010-0250. 14. curtis ka, black k. shoulder pain in female wheelchair basketball players. j orthop sports phys ther 1999; 29(4):225-231. doi: 10.2519/jospt.1999.29.4.225.15. tavakol m, dennick r. making sense of cronbach’s alpha. int j med ed 2011; 2:53-55. doi: 10.5116/ijme.4dfb.8dfd. 15. morgan ga, leech nl, gloeckner gw,et al. spss for introductory statistics: use and interpretation. 2nd ed. mahwah, nj: lawrence erlbaum associates inc; 2004: 103. 16. jackson dl, hynninen bc, caborn dn, et al. electrodiagnostic study of carpal tunnel syndrome in wheelchair basketball players. clin j sport med 1996; 6(1):27-31. pmid: 8925362. https://www.paralympic.org/rio-2016 https://iwbf.org/wp-content/uploads/2016/08/%202014_iw%20bf%20rules_v2.pdf https://iwbf.org/wp-content/uploads/2016/08/%202014_iw%20bf%20rules_v2.pdf https://doi.org/10.2165/00007256-200029040-00003 https://doi.org/10.2165/00007256-200029040-00003 https://doi.org/10.1249/01.mss.0000048635.83126.d4 https://doi.org/10.2519/jospt.1999.29.4.225 sajsm 595 (commentarty).indd commentary 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license teams with lower injury rates have greater success in the currie cup rugby union competition l t starling, msc division of exercise science and sports medicine, department of human biology, university of cape town, cape town, south africa corresponding author: l t starling (lindsay@lstarling.co.za) success in team sports is the result of the effective combination of numerous factors, such as physical fitness, psychological factors, tactical strategies and player skill level. [1] the influence of injuries on team success is a factor which is underrepresented in the literature. injuries result in players being unavailable for selection which, depending on the severity of the injury, may fluctuate from one match to the whole season. this may hamper the selection of the strongest team or force the coach to use different player combinations. both of these points can potentially result in changes to team strategy, disruption of team dynamics and invoke psychological stress and anxiety among teammates during match preparation. it has also been found that pre-injured athletes often experience heightened anxiety when reentering the team due to a lack of confidence in the previously injured body part and uncertainty around their return to the preinjury level of performance.[2] an athlete experiencing re-injury anxiety may be hesitant to push at maximum effort which, in conjunction with their affected psychological state, may negatively affect team dynamics and performance.[2] studies in professional football have reported strong correlations between lower injury measures and team success.[6-8] the association between a low incidence of injury and superior performance during a season may be even more relevant in sports with a higher incidence of injury than football, such as rugby union. to date only two studies have examined the association between injuries and team success in rugby union.[3,4] the first study showed a moderate correlation between average days lost per team and final league position across two seasons in professional teams.[3] the other study reported negative associations between injury measures in elite players and team success across seven seasons.[4] it is tempting to conclude an association between injuries and team success, however, more data are needed before this can be made with any confidence. this is a challenge to examine in a study because many factors influence team success which have to be accounted for. for example, changes in coaching and medical staff across seasons, the relevant importance of each player in the squad, and changes in competition structure across the years would require data to be collected over several seasons to provide sufficient statistical power for this analysis. an opportunity to investigate this question in the currie cup competition, the south african rugby union premiership division competition, arose through the sa rugby injury and illness surveillance and prevention project, which is entering its sixth year.[5] discussion time-loss injuries and team success in the currie cup competition when considering the average time-loss (≥ 1 day training/match play missed) injury rate of teams who ranked at the top, in the middle, and at the bottom of the competition across five seasons of the currie cup, there was an increase in the average injury rate for teams which ranked further away from first position. the average injury rate of teams in first position was significantly lower than those in last position [48 injuries per 1 000 player hours (95% c.i 20 to 76) vs 130 injuries per 1 000 player hours (95% c.i 79 to 180)] (fig. 1). this trend, whereby teams who are more successful in the competition have lower injury rates than those who are less successful, follows the pattern found in both international rugby union [3,4] and football data respectively.[6–8] it is apparent that across five seasons of the currie cup competition the teams in first position had, on average, a significantly lower injury rate than those in last position. table 1 presents the final competition position of each team for each year, with each letter representing a team in the competition. the team with the lowest time-loss injury rate for each year is highlighted in yellow. looking at the final competition position of the team with the lowest injury rate for each year, these teams are either in first or second position (table 1). background: professional football teams that rank high on the log at the end of the season generally have fewer injuries than teams that rank lower on the log. this highlights the importance of implementing injury prevention measures, not only to protect player welfare and ensure their longevity in the sport, but also to improve the performance of the team. the association between a low incidence of injury and superior performance during a season may be even more relevant in sports with a higher incidence of injury than football, such as rugby union. discussion: to examine this association in the south african currie cup rugby union competition, time-loss (≥ 1 day training/match play missed) injury data and final position in the competition was examined over five-seasons. teams who ranked in 1st position had significantly lower average injury rates than teams who ranked in last position [48 injuries per 1 000 player hours (95% c.i 20 to 76) vs 130 injuries per 1 000 player hours (95% c.i 79 to 180)]. more specifically, the team with the lowest injury rate in each season ranked in 1st or 2nd position. this team performance aspect of injury prevention should be highlighted more. in particular, this should be used to assist with communicating the importance of injury prevention programmes to stakeholders directly involved with budgetary allocations in the team. keywords: rugby, performance, injury prevention, health education s afr j sports med 2019; 31:1-2.doi: 10.17159/2078-516x/2019/v31i1a6401 mailto:lindsay@lstarling.co.za http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6401 https://orcid.org/0000-0003-1275-6908 commentary sajsm vol. 31 no. 1 2019 2 epidemiological studies identify injury risk factors and areas where sports governing bodies can implement injury prevention strategies.[5] however, successful implementation of an injury prevention measure requires support from all key stakeholders. injury prevention strategies are often communicated through the importance of protecting player welfare, with the need for the intervention justified by how it will reduce the risk of injury in a certain aspect of the game. injury prevention strategies communicated in this respect generally appeal to stakeholders whose primary interest is in the medical management of players. the importance of an injury prevention measure may be better explained to other stakeholders in a team through assessing the association between injuries and the primary interest of that stakeholder. for coaches, whose primary interest is in the performance of the team, the influence of injuries on performance should be explored. coaches are more likely to be concerned about factors which contribute to team success and which can be controlled, such as player fitness levels and tactical strategies. it may be more practically relevant to coaches to describe the interplay between injuries, these factors and performance. administrators with budgetary control also need to be aware of the influence of injuries on performance to highlight the importance of allocating funds to injury prevention resources. there are many confounding factors which need to be considered when inferring an association between injuries and performance, however, to encourage an inclusive decision and buy-in from all stakeholders in a team. the interplay between injuries, performance and budget should also be explored. there needs to be a paradigm shift in the communication of injury prevention strategies to these key stakeholders, whose primary interest is in the performance of the team. conclusion teams who perform better in the currie cup competition have lower injury rates than those who perform poorly. this association should be used to highlight the importance of injury prevention to key stakeholders of teams. this communication approach to coaches and administrators may improve their support and adoption of comprehensive injury prevention programmes. references 1. arnason a, sigurdsson sb, gudmundsson a. et al. physical fitness, injuries, and team performance in soccer. med sci sports exerc 36(2) 2004; 278–285. [doi: 10.1249/01.mss.0000113478.92945.ca] 2. ford jl, ildefonso k, jones ml, et al. sport-related anxiety: current insights. open access j sports med 8 2017; 205–212. [doi: 10.2147/oajsm.s125845] 3. brooks j h, fuller cw, kemp sp, et al. an assessment of training volume in professional rugby union and its impact on the incidence, severity, and nature of match and training injuries. j sports sci 26(8) 2008: 863–873. [doi: 10.1080/02640410701832209] 4. williams s, trewartha g, kemp sp, et al et al. time loss injuries compromise team success in elite rugby union: a 7-year prospective study. br j sports med 50(11) 2016: 651–656. [doi: 10.1136/bjsports-2015-094798] 5. starling l, readhead c, viljoen w, et al. the currie cup premiership competition injury surveillance report 2014-2017. s afr j sports med 30(1) 2018: 1–42. [doi: 10.17159/2078-516x/2018/v30i1a5720] 6. eirale c, tol jl, farooq a, et al. low injury rate strongly correlates with team success in qatari professional football. br j sports med 47(12) 2013; 807–808. [doi: 10.1136/bjsports-2012-091040] 7. ekstrand j, waldén m, hãagglund m. risk for injury when playing in a national football team. scand j medsci sport 14(1) 2004; 34–38. [pmid:14723786] 8. hãägglund m, waldén m, magnusson h, et al. injuries affect team performance negatively in professional football: an 11-year follow-up of the uefa champions league injury study. br j sports med 47(12) 2013; 738– 742. [doi: 10.1136/bjsports-2013-092215] fig. 1. average injury rate/1 000 player hours (95% ci) for time-loss match injuries for teams ranked in first (n = 5), middle (n = 5) and last (n = 5) position in the currie cup competition from 2014 – 2018. asterisks (*) indicates average injury incidence is significantly different to another group. table 1. final position of each team in the currie cup competition from 2014 – 2018, with each letter representing a team in the competition. the team with the lowest injury rate in each year is highlighted in yellow. final competition position 2014 2015 2016 2017 2018 1st a b e a c 2nd b a d c a 3rd c d a b b 4th d e b d d 5th e c c e f 6th f f h f h 7th g g i h e 8th h h f 9th g a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm original research 1 sajsm vol. 30 no. 1 2018 the impact of anterior knee pain on the quality of life among runners in under-resourced communities in ekurhuleni, gauteng, south africa s h kunene1,2, msc, s ramklass2, phd, n p taukobong3, phd 1physiotherapy department, university of the witwatersrand, johannesburg, south africa. 2school of clinical medicine, university of kwazulu-natal, durban, south africa. 3institutional planning department, sefako makgatho health sciences university, pretoria, south africa corresponding author: s h kunene (siyabonga.kunene@wits.ac.za) anterior knee pain (akp) is the most common knee problem experienced by athletes, especially long-distance runners. patients with akp present with pain that is localised to the anterior aspect of the knee beneath or around the patella edges which may be triggered by prolonged sitting, squatting, ascending or descending stairs.[1] any activity that may cause compression on the patellofemoral joint could trigger this kind of pain. the causes of akp may differ among patients, depending on their knee structures. soft tissue, such as the lateral retinaculum and the infrapatellar fat pad, may also be cause pain among athletes.[1] during normal knee flexion the patella usually moves towards the medial aspect of the joint in order to sit comfortably within the intercondylar notch until the 130° range is reached, after which it moves back laterally.[1] all these movements are coordinated by the quadriceps muscles, particularly the vastus medialis oblique (vmo) and vastus lateralis. the lateral structures of the knee are often much stronger than the medial aspects. therefore any poor coordination of the knee structures, such as muscle weakness or excessive load during running, can cause irritation or pressure and pain on the patella and other associated structures. there are several internal and external factors that contribute to akp among runners. the internal factors consist of those that are specific to each runner, including muscle and tendon forces, while the external factors are air resistance, gravity and ground reaction forces.[2] the prevalence of akp ranges between 15-45% globally [3], with mainly females, younger adults and adolescents affected[1,4,5]. anterior knee pain accounted for 40% among the same population in an earlier study by these authors.[6] the following modifiable intrinsic risk factors were found to have contributed significantly to akp among this population: tight hamstrings (p=0.051, or=1.021); tight iliotibial band (p=0.046, or=1.122); weak quadriceps (p=0.040, or=0.154), weak hip control muscles (p=0.004, or=1.131) and patellar tilt abnormalities (p=0.015, or=1.332) [6]. anterior knee pain has a negative impact on the quality of life (qol) of many athletes at different sporting levels, dependent on the severity of the symptoms.[7] anterior knee pain is not only characterised by physical features but also nonphysical features which may influence the recovery of patients.[8] physical features may include, for example, limitations in general physical functioning, physical roles, the body’s pain perception.[7,9] non-physical features may include general mental health (psychological distress and well-being), emotional problems, social functioning and in the motivation to perform a task. [7,9] this is especially so if there are no rehabilitation programmes for anterior knee pain available or if the rehabilitation programmes are not sufficiently comprehensive to address all the problems associated with this condition. few authors have conducted qol studies among athletes with akp. some of the available studies showed that injuries impacted on individuals’ qol in a negative way.[7,9] these background: anterior knee pain (akp) is the most common injury among runners and has a negative impact on the quality of life (qol) of many athletes. objectives: to determine the impact of akp on the qol among runners in under-resourced communities in ekurhuleni, gauteng, south africa. methods: a cross–sectional study design was used. a population of 73 runners with akp was included. participants included runners aged 13 to 55 years with no history of knee surgery, traumatic or degenerative knee conditions. the sf-36 questionnaire was used to collect data. ethical clearance, permission from club managers and consent from participants were obtained. data were collected over six weeks and analysed using spss. descriptive statistics included frequencies, percentages, means, standard deviations and ranges. inferential statistics included the comparison of means using the anova test. results: the lowest sf-36 mean scores were in two health domains: role limitation due to emotional problems (59) and vitality (59). highest scores were in the general physical functioning domain (72). females presented with lowest sf-36 scores (48) on role limitation due to emotional problems with noticeable difference (p=0.03). youth presented with lowest scores (62) on the social functioning domain (p=0.001). significant differences were noted on sf-36 scores between running experienced groups on the following domains: physical functioning (p=0.03), role limitation due to physical problems (p=0.01), vitality (p=0.001), general mental health (p=0.001) and social functioning (p=0.001). the most affected was the group with three-five years of running experience which presented with scores ranging between 46 and 65. significant mean differences were also noted between bmi groups in the social functioning domain (p=0.01) where overweight and obese groups were mostly affected by akp. conclusion: this study highlighted a need to prevent, treat and rehabilitate akp. multidimensional community-based rehabilitation programmes are recommended. keywords: patellofemoral pain, state of health, athletes, poorresourced communities s afr j sports med 2018;30:1-6. doi: 10.17159/2078-516x/2018/v30i1a4947 http://dx.doi.org/10.17159/2078-516x/2018/v30i1a4947 original research sajsm vol. 30 no. 1 2018 2 experiences can also affect an athlete’s rehabilitation programme and return-to-sport.[10] maclachlan et al. [8] reported qol that ranged from 28% to 62% among individuals with akp. there are limited studies on qol for runners with akp from under-resourced communities. it is widely known that people who live in these communities usually present with poor health outcomes compared to those in well-resourced socioeconomic communities.[11] as mentioned above, the population in the authors’ earlier study already had a akp and the associated risk factors.[6] therefore it is important to know the impact of akp on the qol in this population in order to develop specific and comprehensive prehabilitation or rehabilitation programmes. this study is a continuation of these authors’ previous study that determined the presence of akp in runners in under-resourced communities.[6] methods a cross-sectional study included a sample of 183 out of 347 long-distance recreational runners from six developmental running clubs in under-resourced peri-urban communities in ekurhuleni, gauteng, who had undergone physical screening for akp in these authors’ previous study.[6] a raosoft statistical tool was used to calculate the sample size, taking into consideration a 95% confidence level, 5% margin of error and 50% response distribution. an equal representative number of runners were recruited from each running club using a convenience sampling method. the participants were recruited during their training sessions at their various training grounds. participants included runners aged between 13 and 55years-old with no history of knee surgery, traumatic or degenerative knee conditions. seventy-three runners who presented with akp according to the results of the akp physical screening were included in the qol survey. the number of participants from each club were as follows: 13 from club one, 12 from club two, 10 from club three, 14 from club four, 8 from club five, 16 from club six. the akp screenings mentioned in these authors’ previous study included the use of a standardised akp questionnaire consisting of 13 short questions that assessed the participants’ knee symptoms and any functional limitations associated with akp.[6] further objective screening by a physiotherapist was done using five physical screening tests, namely, a patellar apprehension test, vastus medialis coordination test, eccentric step test, clarke’s test, and waldron’s test. the sf-36 questionnaire [12] was adapted to collect qol data among the participants. a demographic profile was added as section a and included information on gender, age, height, weight, number of races completed and running experience,. section b was the sf-36 questionnaire which consisted of 36 items within eight health domains, all related to akp: general physical functioning (ten items), bodily pain (two items), role limitation due physical problems (four items), role limitation due to personal or emotional problems (three items), social functioning (two items), general mental health (five items), vitality (energy/fatigue) levels (four items) and general health perceptions (five items). it also included a single item that provided an indication of perceived change in health status due to akp in the past twelve months. the questionnaire consisted of eight scaled scores which are the sum of questions in each domain. each scale is scored 0-100. the lower the score the greater the disability it represents and the higher the score the lower the disability. according to a systematic review done by hart and kang, the sf-36 is a reliable and valid tool when used in physical activity research.[13] ethical clearance was granted by the biomedical research committee at the university of kwazulu-natal (bfc377/15). permission to conduct the study among running clubs was granted by the central gauteng athletics’ manager. runners were first provided with information leaflets which explained the purpose, objectives and methods of the study. all participants signed informed consent forms before they participated. consent was obtained from the parent guardian of participants younger than 18 years. a pilot study was conducted among eight participants prior to the main study. no adjustments were required on the data collection tools used and hence the data obtained were included in the main study. during data collection, the first author hand-delivered the akp questionnaire to the participants and physically screened them for akp. the sf36 questionnaire was then immediately distributed among participants who responded positively to the akp screening procedure. data collection took place during club training sessions over a period of six weeks. it took approximately 30 minutes to collect data from each participant. the data were initially captured on a microsoft excel spreadsheet and later imported into spss for analysis. descriptive and inferential statistics were used to analyse the data. descriptive statistics included the calculation of frequencies, means, medians, modes, standard deviations and ranges. an inferential statistics anova test was undertaken to compare the means for the eight sf-36 domains against the demographic profiles. the confidence level was set at 95% and the level of significance at p = 0.05. scoring of the sf-36 items was done prior to the statistical analyses in a two-step process. firstly, coding, summing and transforming dichotomous and ranked response categories was done. the scoring of items ranged from zero (worse possible health state) to 100 (best possible health state). scores represented the percentage of the total possible score achieved. secondly, items in the same dimension were averaged to create the eight-scale scores. results anterior knee pain was present in 40% (73) of participants according to the akp screening.[6] further results from the akp screening are presented and discussed in detail in a previous study by these authors. the following results will focus on the results obtained from the sf-36 survey. as mentioned, seventy-three runners completed the sf-36 questionnaire. the details are indicated in table 1 below, the original research 3 sajsm vol. 30 no. 1 2018 majority of participants were males (55%) and young (45%) with one to three years of running experience (30%). most participants presented with normal body mass index (bmi) (60%). participants presented with high sf-36 scores in the following domains: general physical functioning (72), social functioning (70) and general health (70). these results indicate a good state of health or low possible disability in these domains among participants. low scores were noted in the following dimensions: role limitation due to physical problems (62), role limitation due to emotional problems (59), vitality (energy/fatigue) levels (59), general mental health (68) and bodily pain (63) (table 2). this indicates a fair state of health or a slightly high possible disability in these domains. the perceived change in health was found to have a mean of 58. (table 2). table 3 presents a significant mean difference between the two gender groups concerning role limitation due to emotional problems (p = 0.03). females presented with a poor state of health (48) compared to males (68). older participants between 36 55 years presented with a better state of health in their social functioning domain (81) compared to other age groups. a higher significant mean difference was found between age groups regarding social functioning (p = 0.001). a significant mean difference was also found between running experience and the following health domains: general functioning (p = 0.03), role limitation due to physical problems (p = 0.01), vitality (p = 0.00), general mental health (p = 0.001) and social function (p = 0.001). younger participants had a better state of health compared to other age groups. participants with normal bmi presented with the highest scores in the following domains: role limitation due to physical problems (67) and social functioning (74). participants who were underweight presented with highest scores in role limitation due to emotional problems (78). a significant mean difference was found between bmi and social functioning domain (p = 0.01). no significant difference was noted between various groups regarding the perceived change in their health: gender (p = 0.33), age (p = 0.55), years of running experience (p = 0.32) and bmi (p = 0.27). a perceived change in health scored higher in males (64), indicating a favourable state of health among this group compared to females (52). young participants (13-17 years old) scored higher in this section compared to other age groups. runners with the least years of experience (less than one year) scored highest compared to other groups (71). participants with bmi below normal (less than 18.5) also showed highest scores (71) compared to other groups. discussion anterior knee pain among athletes has been widely investigated but few studies have covered qol among runners with akp, especially in under-resourced communities. most studies focused on prevalence, incidence, aetiology, risk factors and the investigation of the effectiveness of different interventions, and physical therapy approaches.[7,14,15] repetition of the opening sentence of this section. again, this is repetition. this study found a low sf-36 score of 59 in two health domains: role limitation due to emotional problems, and vitality. thus the participants’ ability to fulfil their various roles were impacted on negatively due to the emotional problems caused by akp. these problems may cause athletes to reduce the amount of time spent on their running activities, thus impacting on their performance.[7,16] the low vitality scores indicate that akp had a negative impact on the participants’ energy and fatigue levels. athletes felt less enthusiastic, less energetic, and even lost interest in their running-related activities. the highest sf-36 score was found in the general physical functioning domain (72), indicating a better health state compared to other domains. other sf-36 health domains in this study ranged between 59-72. all these scores were generally lower when compared to other studies. according to cheung table 1. demographics profile (n = 73) demographics categories n % gender male female 40 33 55 45 age 13 17 18 35 36 55 18 33 22 25 45 30 running experience <1 year 1 3 years 3 5 years 6 10 years >10 years 7 22 19 12 13 10 30 26 16 18 body mass index (bmi) <18.5 18.5 24.9 25 29.9 >30 12 44 14 03 16 60 19 4 table 2. sf-36 descriptive statistics for runners with anterior knee pain (akp), n = 73 sf-36 dimensions no. of items mean median mode sd min max general physical functioning 10 72 80 80 22 25 100 role limitation due to physical problems relating to akp 4 62 75 100 38 0 100 role limitation due to emotional problem relating to akp 3 59 67 100 38 0 100 vitality (energy and fatigue) 4 59 60 60 19 5 100 general mental health 5 68 68 52 18 20 100 social functioning relating to akp 2 70 75 75 17 37 100 bodily pain relating to akp 2 63 68 78 25 10 100 general health perception 5 70 65 50 18 35 100 change in health 1 58 50 50 28 0 100 data are presented as a score between 0 and 100. sd, standard deviation; min, minimum score; max, maximum score original research sajsm vol. 30 no. 1 2018 4 et al, amateur athletes with akp in china presented with higher sf-36 scores indicating a better health state than those presented in this study.[7] their lowest score was 62 in role limitation due to emotional health problems. their highest sf36 score was 82 in the social functioning domain. the scores for other sf-36 domains ranged between 62–82. athletes with akp in better resourced communities in china presented with superior health states compared to those in this study. there were significant differences between gender groups in this study, females had low sf-36 scores on role limitation due to emotional problems (48) when compared to men. youth athletes had a significantly poorer health state with regard to social functioning (62) when compared to other groups. the reason for these findings could be as a result of the high prevalence of akp reported in various studies among females and young athletes.[4,5]. anatomical and biomechanical factors may be the contributing factors to the high prevalance of akp among young runners but the most common underlying reasons are overuse injuries. these affect mainly young runners as a result of a sudden increase in their intensity, duration and volume of running activity; inadequate sports-specific training; poor training techniques and inappropriate sporting equipment.[17] if professional rehabilitation services are scarce in communities (such as the communities in this study), injuries and risk of injuries are bound to increase resulting in the high prevalance of akp in this study. significant differences were noted between running experience and five health domains namely, physical functioning, role limitation due to physical problems, vitality, general mental health and social functioning. runners with 3– 5 years of running experience reported with poor state of health table 3. relationship between sf-36 domains and demographic profile (n = 73) demographics parameter physical functioning role limit due to physical problems role limit due to emotional problems vitality general mental health social functioning bodily pain general health perception change in health gender male mean 70 64 68 59 70 67 63 69 64 sd 21 38 35 18 19 17 24 18 5 female mean 74 60 48 61 65 73 64 70 52 sd 22 38 40 20 17 18 26 19 4 p 0.43 0.67 0.03 0.51 0.20 0.16 0.84 0.88 0.33 age (in years) 13-17 mean 75 60 65 63 63 69 70 70 64 sd 23 42 31 22 21 19 18 18 31 18-35 mean 67 57 54 55 67 62 64 68 57 sd 22 39 42 19 15 13 24 19 19 36-55 mean 77 72 62 64 73 81 57 70 55 sd 20 33 38 14 20 16 28 18 35 p 0.18 0.36 0.54 0.14 0.18 0.00* 0.28 0.94 0.55 running experience (in years) < 1 mean 83 93 71 85 85 89 72 78 71 sd 28 19 30 17 23 20 17 22 27 1 – 3 mean 77 69 61 65 70 64 66 74 63 sd 19 37 37 11 16 11 21 19 24 3 5 mean 60 49 46 52 56 63 64 65 57 sd 23 38 45 18 13 14 22 16 25 6 10 mean 70 40 53 55 66 73 52 67 56 sd 18 38 26 18 14 20 34 15 32 >10 mean 78 73 74 53 73 75 62 64 46 sd 17 33 39 20 21 18 28 19 32 p 0.03* 0.01* 0.23 0.00* 0.00* 0.00* 0.46 0.21 0.32 bmi <18.5 mean 65 50 78 54 62 57 65 67 71 sd 28 41 26 16 19 14 24 12 26 18.5-24.9 mean 74 67 58 57 70 74 66 68 54 sd 20 34 40 21 18 19 23 19 29 25-29.9 mean 76 66 52 70 70 69 57 77 61 sd 19 42 34 11 18 8 28 18 25 >30 mean 53 17 22 55 49 54 44 52 50 sd 28 29 38 13 2 7 28 3 0 p 0.23 0.09 0.09 0.13 0.15 0.01* 0.34 0.12 0.27 mean and sd are presented as a score between 0 and 100. * indicates significant p value < 0.05 sd, standard deviation; bmi, body mass index original research 5 sajsm vol. 30 no. 1 2018 compared to others. anterior knee pain affected this group’s ability to participate in their general and role-specific physical activities, including running and other related activities, vitality levels (energy or enthusiasm for running-related activities), general mental health (psychological distress and wellbeing) and social functioning. all of these are critical health components required for a good state of health for runners. participants with less than one year of running experience had better health states in these five sf-36 health domains, followed by those with the most years of running experience (more than 10 years). the most affected group was that with three to five years of running experience with sf-36 scores that ranged from 46 – 65. in a previous study by these authors, running experience was also found to have with a high level of akp (p = 0.04, 2 = 8.389 in runners with three to five years of experience. [6] the results from the previous study therefore justify why runners in this group present with poor quality of life when compared to other groups. notable differences were also noted among the bmi group, where participants who were overweight and obese scored lower in this role limitation due to physical problems, emotional problems and social functioning domains. these results could indicate that participants who are overweight and obese are generally not satisfied with their health state compared to those with a normal weight and who are underweight. this could be as a result of the known negative impact overweight and obese conditions have on health in general. the presence of akp could result in feeling of low self-esteem, especially if their motive for running was to control their weight. the results obtained in this present study shows that anterior knee pain compromises the physical and mental components of the athlete, including their psychological health. injured athletes usually experience psychological emotions that relate to their injuries, and which can have a detrimental effect on their wellbeing and ability to perform optimally. these experiences may also affect these athletes’ rehabilitation programmes and their return-to-sport.[10] an acsm consensus statement , confirms that injured athletes experience stress with behavioural, physical and psychological symptoms.[10] these emotions occur when an injury is not resolved and becomes worse over time. according to a systematic review by maclachlan et al.[8], anxiety, depression, catastrophising and fear of movement were identified as psychological features that may be increased in individuals with akp. these characteristics correlated with pain and reduced physical function among people with akp have also been identified as barriers to injury recovery[18] thus limiting the potential for patients to improve during rehabilitation.[19] therefore these need to be considered during assessment, treatment and the rehabilitation of akp. if athletes with akp are not rehabilitated properly, their condition may become problematic and could result in osteoarthritis, further impacting on their qol.[7] poor community rehabilitation services could be one of the reasons why our current population presented with a high prevalence of akp[6] and poor quality of life. rehabilitation services provided by health professionals, such as the physiotherapist, biokineticist, podiatrist, psychologist, are therefore critical in the prevention, treatment and rehabilitation of injuries. the outcomes of this present study highlights the need for such services. it is suggested that comprehensive community-based rehabilitation programmes are necessary to address both the physical and psychological needs of the running population, especially from under-resourced communities. conclusion this study highlighted the negative impact of akp on the quality of life among runners and the need not only to address physical features of akp but also the non-physical features, such as the psychosocial, emotional and mental factors when formulating strategies to improve qol among the running population with akp. a holistic approach in assessing, treating and rehabilitating akp is necessary to ensure all athletes’ needs are met. acknowledgements: the authors would like to thank the university of kwazulu-natal and the university of the witwatersrand for providing the necessary resources for this study. central gauteng athletics are thanked for providing the authors with permission to conduct this study. thanks to the ekurhuleni runners for their participation. references 1. brukner p, khan km. clinical sports medicine 4th ed. sydney: mcgraw-hill australia, 2011:684-714. 2. hreljac a. etiology, prevention, and early intervention of overuse injuries in runners: a biomechanical perspective. phys med rehabil clin n am 2005;16(3):651-667. [doi: 10.1016/j.pmr.2005.02.002] 3. cook c, hegedus e, hawkins r, et al. diagnostic accuracy and association to disability of clinical test findings associated with patellofemoral pain syndrome. physiother can 2010;62(1):17-24. [doi: 10.3138/physio.62.1.17] 4. van gent rn, siem d, van middelkoop m, et al. incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. br j sports med 2007;41(8):469–480. [doi:10.1136/bjsm.2006.033548] 5. boling m, padua d, marshall s, et al. gender differences in the incidence and prevalence of patellofemoral pain syndrome. scand j med sci sports 2010;20(5):725-730. [doi: 10.1111/j.16000838.2009.00996.x] 6. kunene sh, ramklass s, taukobong np. anterior knee pain and its intrinsic risk factors among runners in under-resourced communities in ekurhuleni, gauteng. s afr j physiother: in press 7. cheung rt, zhang z, ngai sp. different relationships between the level of patellofemoral pain and quality of life in professional and amateur athletes. am j phys med rehabil 2013;5(7):568-572. [doi:10.1016/j.pmrj.2012.12.007] 8. maclachlan lr, collins nj, matthews ml, et al;. the psychological features of patellofemoral pain: a systematic review. br j sports med 2017;51(9):732–742. [doi:10.1136/bjsports2016-096705] 9. mcallister dr, motamedi ar, hame sl, et al. quality of life assessment in elite collegiate athletes. br j sports med 2001;29(6):806-810. [doi:10.1177/03635465010290062201] 10. american college of sports medicine, american academy of family physicians, american academy of orthopaedic surgeons, et al. psychological issues related to injury in athletes and the team physician: a consensus statement. med sci sports exerc https://doi.org/10.1016/j.pmr.2005.02.002 original research sajsm vol. 30 no. 1 2018 6 2006;38(11):2030-2034. [doi: 10.1249/mss.0b013e31802b37a6] 11. finch c, mahoney m, townsend m, et al. rural sports and recreational injuries in australia: what do we know? aust j rural health 2003;11(3):151-158. [doi: 10.1046/j.1440-1584.2003.00500.x] 12. ware je jr, sherbourne cd. the mos 36-itenrm short-form health survey (sf-36): i. conceptual framework and item selection. med care 1992;30(6):473-483. [doi: 10.1097/00005650-199206000-00002] 13. hart pd, kang m. reliability of the short-form health survey (sf-36) in physical activity research using meta-analysis. world j prev med 2015; 3(2):17-23. [doi:10.12691/jpm-3-2-1] 14. csintalan rp, schulz mm, woo j, et al. gender differences in patellofemoral joint biomechanics. clin orthop relat res 2002; (402):260-269. [doi:10.1097/00003086-200209000-00026] 15. davis is, powers cm. patellofemoral pain syndrome: proximal, distal, and local factors, an international retreat, april 30-may 2, 2009, fells point, baltimore, md. j orthop sports phys ther 2010;40(4):a1–a16. [doi: 10.2519/jospt.2010.0302] 16. paxton ew, fithian dc. outcome instruments for patellofemoral arthroplasty. clin orthop relat res 2005;(436):66-70. [doi:10.1097/01.blo.0000171544.38095.77] 17. patel dr, villalobos a. evaluation and managment of knee pain in young athletes: overuse injuries of the knee. transl pediatr 2017;6(3):190-198. [doi:10.21037/tp.2017.04.05] 18. henschke n, maher cg, refshauge km, et al. prognosis in patients with recent onset low back pain in australian primary care: inception cohort study. bmj 2008;337:a171. [https://doi.org/10.1136/bmj.a171)] 19. sullivan mj, adams h, thibault p, et al.. initial depression severity and the trajectory of recovery following cognitive-behavioral intervention for work disability. j occup rehabil 2006;16(1):63-74. [https//doi.org/10.1007/s10926-005-9013-0] sajsm 519.indd original research sajsm vol. 26 no. 4 2014 109 objectives. to determine the prevalence of overweight and obesity among grade 1 learners, taking into account age, gender, race and school socioeconomic profile. methods. the study is based on the baseline prevalence of overweight and obesity as part of the ongoing 6-year longitudinal nw child health integrated learning and development (nw-child) study. stratified random sampling was used to identify 20 schools from four educational districts across all five quintiles of schools in the north west province (nwp) of south africa (sa). a total of 816 (419 boys, 397 girls) grade 1 learners with a mean age of 6.80 (standard deviation 0.39) years participated in the study, including 567 black learners, 218 white learners and 31 learners from other race groups. standard anthropometric techniques and international body mass index (bmi) cut-off points for children were used to determine overweight and obesity. results. a combined prevalence of overweight and obesity (ow/ob) of 11.1% was found, of which 7.5% were overweight and 3.6% obese. although 7-year-old children showed a significantly higher prevalence of overweight (10.5%) than 6-year-old children (6.3%; p<0.05), obesity levels were more prevalent among 6-year-old children (4.7%) than 7-year-old children (2.3%). although not significant, a higher prevalence of overweight (9.3 v. 6.4%) and obesity (4.3% v. 3.3%) was found in girls than boys. for the whole sample, white children displayed a significantly higher prevalence of ow/ob compared with black children (19.7% v. 8.8%; p<0.05), and the prevalence of ow/ob was higher in 4th(18.1%) and 5th(21.2%) quintile schools (which are associated with higher socioeconomic status (ses)) than in quintile 1 to quintile 3 schools (5.1%, 8.7%, 6.1%, respectively; p<0.05). conclusions. more than 10% of grade 1 learners in the nwp of sa were overweight or obese, with the prevalence being significantly lower in lower ses schools and among black children. prevention strategies are needed to combat overweight and obesity, and the associated negative consequences of these health risks. obesity levels in black children should also be monitored because of continuing economic transition, and taking into account increasing overweight and obesity in black south african adults. s afr j sm 2014;26(4):109-114. doi:10.7196/sajsm.519 prevalence of overweight and obesity in grade 1 learners in the north west province of south africa: the nw-child study a e pienaar, phd; g kruger, msc physical activity, sport and recreation (phasrec), faculty of health science, north-west university, potchefstroom, south africa corresponding author: a e pienaar (anita.pienaar@nwu.ac.za) over weight and obesity have become a global epidemic, especially among children.[1] the statement from hills et al.[1] emphasises the seriousness of obesity in children: ‘today’s generation of children will be the first for over a century for whom life expectancy falls.’ over weight and obesity can be defined as abnormal excessive accumulation of body fat,[2] which is the result of an imbalance between energy intake and energy expenditure. one billion people in both developed and developing countries are affected by overweight and obesity.[2] in 2010, nearly 43 million children <5 years old worldwide were overweight.[2] the prevalence of overweight and obesity in canada, norway and america in children aged between 6 and 11 years was 6.3%, 10.1% and 20.7%, respectively.[3] while the prevalence of overweight in children has doubled over the past 2 decades, severe obesity is also becoming a more general phenomenon among children; a study in america indicates that rates of severe obesity have tripled in the last 25 years, where 3.8% of children aged 2 19 years were found to be severely obese in the period 1999 2004, with significant differences in race, gender and poverty.[4] some parts of south africa (sa) are more affected by overweight and obesity, and possible contributing factors are improved socioeconomic status (ses), urbanisation and a decrease in physical activity.[5] a study of 6 13-year-old sa children of different races found that 14.0% of boys and 17.9% of girls were overweight, and 3.2% of boys and 4.9% of girls were obese, with white children more overweight and obese than black and mixed-ancestry children of 6 or 7 years.[6] the national food consumption survey (nfcs) (n=2 894), which investigated 1 8-year-old children in 1999, indicated that 6.7% of children were overweight and 3.7% were obese.[7] sa statistics released in 2013 for 10 ‐ 14-year-olds indica ted that overweight and obesity were higher in girls (16.7% and 5.6%, respectively) than in boys (7.5% and 2.7%, respectively).[8] for 6 9-year-old children, an overweight prevalence of 8.4% in 2013 v. 7.8% in the 2005 nfcs, and an obesity prevalence of 3.4% in 2013 v. 2.5% in the 2005 nfcs, are reported.[8] no studies report data on severely obese sa children. obesity places high demands on the health of children. some obesity-related conditions have immediate health effects, while others have long-term chronic consequences.[9] overweight and obesity can lead to numerous negative health conditions, including asthma, cardiovascular illnesses, type 2 diabetes, hypertension and obstructive sleep apnoea.[9] a more sedentary lifestyle is also preferred by obese children compared with non-obese children, and obese children 110 sajsm vol. 26 no. 4 2014 are less active. lowered physical activity levels lead to lower energy expenditure and increased risk of obesity and poor health later in life. graft et al.[10] reported lower gross motor development and aerobic capacity in obese compared with non-obese grade 1 learners with a mean age of 6.7 years in germany. a study by d’hondt et al.[11] found that the general level of motor coordination in obese children is lower when compared with normal-weight children, while inadequate locomotor skills (i.e. jumping and kicking) were also reported. [10,12] children’s fine motor skills are also negatively influenced by overweight and obesity. although overweight and obesity have been studied among sa children, none of these studies have focused on the school beginner. a knowledge gap exists in our understanding of the rates of overweight and obesity in school beginners in sa, and how increased body mass relates to age, gender, race and ses. because overweight and obesity hamper development and wellbeing of school beginners, it is important to obtain more information regarding the current prevalence of these conditions. the objective of this study was to fill this knowledge gap by identifying the prevalence of overweight and obesity among grade 1 learners in the north west province (nwp) of sa, and explore the relationship of overweight and obesity to age, gender, race and school type. method sample size and sampling procedure the research was part of the nw-child (north west child health integrated learning and development) longitudinal study (2010 2016). the sample formed part of the baseline population of the nwchild study (2010) and subjects were selected by means of a stratified random sample. stratification was done by school district, gender and school type in collaboration with the statistical consultation service of north-west university (nwu). to determine the sample, a list of schools in the nwp was obtained from the department of basic education. from these schools, which are grouped into eight education districts, each representing 12 22 regions with ~20 schools (minimum 12, maximum 47) per region, stratified random sampling was used to select regions and schools with regard to population density and school status (quintile 1, i.e. schools from very low economic sectors to quintile 5, i.e. schools from very high economic sectors). the total sample comprised 816 learners (419 boys and 397 girls) with a mean age of 6.78 (standard deviation 0.39) years. the distribution of the learners in the different school quintiles was as follows: quintile 1, n=138; quintile 2, n=159; quintile 3, n=173; quintile 4, n=145; and quintile 5, n=175. the ethnic distribution was 567 black, 218 white, 20 mixed-ancestry and 11 indian learners. ethical clearance ethical approval for the study was obtained from the ethics committee of the nwu (no. 00070 09 a1). permission was also obtained from the department of basic education of the nwp and the principals from the selected schools. informed consent had to be provided for each learner by their parents before they were allowed to participate in the study. anthropometry anthropometric measurements included: height (cm), body mass (kg), skinfolds (subscapular and triceps, mm) and waist circumference (cm). these variables were measured by trained postgraduate students in human movement sciences, specialising in kinderkinetics, who were all level 2 kinanthropometrists. all measurements were done in accordance with the protocol of the international society for the advancement of kinanthropometry.[13] one researcher measured a specific anthropometric measurement throughout the study for reliability purposes. height was measured barefoot to the nearest 0.1 cm by means of a portable stadiometer, and body mass was measured with an electronic scale (bf 511, omron, healthcare europe) to the nearest 0.1 kg. from the height and body mass measurements, the body mass index (bmi) was calculated for each participant (body mass (kg)/height (m2)). the triceps and subscapular skinfolds were measured with a pair of skinfold callipers (harpenden, uk) and each skinfold was measured twice to obtain the average of the two measurements. these skinfold measurements were selected because they show the highest association with the overall percentage of fat in children. intrarater reliability was determined by intraclass correlation coefficients, which showed good reliability for the subscapular (r=0.994) and the triceps (r=0.995) skinfolds. the prevalence of overweight and obesity was determined by using the international age-specific cut-off points provided by cole et al.[14] children are at risk of overweight and obesity if their bmi is >85th and 95th percentiles for age and gender, respectively.[14] data analysis statistica[15] (statsoft, usa) was used to analyse the data. data were analysed as percentages, ranges (minimum, maximum), means and standard deviations. differences in bmi between genders, age groups and black and white learners were determined by means of independent t-testing, where p<0.05 was considered a significant difference. two-way frequency tables were also used for further analyses of the data, where the group was divided according to age, gender, race and school type. statistical significance of differences (p<0.05) was determined by pearson χ2 analysis, while cramér’s v was used to determine effect sizes; the following values were used as an estimation of practical significance: 0.1 (small); 0.3 (moderate); 0.5 (large).[16] results table 1 displays the mean height, weight, fat percentage, skinfold and bmi for the total group and the group separated into 6and 7-yearolds, for the different racial groups, while table 2 presents bmi values for boys and girls divided into 6and 7-year-old groups. owing to the small sample size of indian and mixed-ancestry learners, these racial groups were excluded from comparative analysis. white learners had significantly higher mean height, weight, triceps skinfold and fat percentage compared with black learners for the whole group and at 6 and 7 years of age. only the subscapular skinfold did not differ significantly between the black and white learners for the group as a whole and for 7-year-olds. table 2 indicates no significant gender differences (p<0.05) in bmi for the whole group or 6and 7-year-old subgroups. the bmi of white boys (6and 7-year-olds) and white girls (7-year-old group only) was significantly higher than their black counterparts of the same age and sex. similarly, when the 6and 7-year-old sajsm vol. 26 no. 4 2014 111 boys and girls groups were combined, the white learners had a significantly greater bmi than the black learners. table 3 shows that for the whole group of grade 1 learners, 7.5% were overweight and 3.6% were obese, a total prevalence of overweight and obesity of 11.1%. for the whole group, overweight was most prevalent in girls (9.3%), white learners (13.3%) and quintile 5 schools (16.2%). obesity had the highest prevalence in girls (4.3%), white learners (6.4%) and quintile 4 schools (7.1%). a significantly higher prevalence of overweight in 7-year-old compared with 6-year-old (10.5 v. 6.3%, respectively) learners was found (table 3); however, obesity levels were significantly lower in the 7-year-old group compared with the 6-year-old group (2.3 v. 4.7%, respectively), although these differences only showed small practical significance (cramér’s v=0.1). b m i a n d t h e p r e v a l e n c e o f over weight and obesity were not significantly different between boys and girls (tables 2 and 3). for the whole group, ages 6 and 7 years, white learners had a higher prevalence of obesity and overweight compared with black learners (table 3). the overall prevalence of overweight was also significantly higher (p<0.01; cramér’s v=0.2) in quintile 4 and 5 schools (11.0% and 16.2%, respectively) compared with quintile 1 (5.2%), 2 (4.4%) and -3 (2.3%) schools. similar trends of higher percentages of obesity levels were also seen in quintile 4 and 5 schools. in the 7-year-old group, obesity was only seen among learners in the quintile 4 and 5 schools, with no evidence of obesity in quintile 1 3 schools. in the overall group, obesity levels of school beginners in quintile 4 schools (7.1%) was significantly higher than in the other quintile schools (p<0.05; cramér’s v=0.2). discussion the obj e c t ive of t his study was to d e te r m i ne t he pre v a l e nc e of over weight and obesity in grade 1 learners in the nwp of sa and to determine whether overweight and obesity are related to age, gender, race t ab le 1 . a nt hr op om et ri c m ea su re m en ts o f b la ck , w hi te , m ix ed -a nc es tr y an d in di an le ar ne rs , an d th e w ho le g ro up (6 7 ye ar s) b la ck w hi te m ix ed a nc es tr y in di an g ro up (n =8 16 ) m ea n (s d ) m in . m ax . m ea n (s d ) m in . m ax . m ea n (s d ) m in . m ax . m ea n (s d ) m in . m ax . m ea n (s d ) m in . m ax . 6 ye ar s ol d (n =5 11 ) h ei gh t ( cm ) 11 6. 3 (5 .4 ) 10 0. 8 13 3. 6 12 3. 1 (5 .9 )* 11 1. 2 13 5. 2 11 8. 0 (4 .6 ) 10 9. 7 12 5. 7 11 6. 9 (5 .0 ) 11 1. 1 12 0. 1 11 8. 2 (6 .2 ) 10 0. 8 13 5. 2 w ei gh t ( kg ) 20 .8 (4 .3 ) 13 .7 68 .6 24 .2 (4 .9 )* 16 .9 42 .6 21 .9 (9 .1 ) 16 .3 55 .3 21 .0 (3 .9 ) 18 .3 25 .5 21 .8 (4 .9 ) 13 .7 68 .6 fa t ( % ) 14 .9 (4 .2 ) 6. 5 39 .4 16 .3 (5 .3 )* 7. 3 39 .0 13 .6 (8 .1 ) 7. 6 42 .7 17 .4 (3 .7 ) 13 .1 19 .5 15 .2 (4 .7 ) 6. 5 42 .7 tc s f ( m m ) 7. 7 (3 .0 ) 3. 3 25 .0 9. 8 (3 .9 )* 4. 0 23 .3 7. 3 (5 .8 ) 4. 3 28 .5 10 .5 (4 .3 ) 5. 5 13 .3 8. 3 (3 .4 ) 3. 3 28 .5 sc s f ( m m ) 6. 7 (2 .9 ) 3. 0 30 .3 6. 1 (3 .3 )* 2. 5 27 .3 5. 9 (5 .0 ) 3. 0 24 .0 6. 9 (1 .5 ) 5. 3 8. 0 6. 5 (3 .1 ) 2. 5 30 .3 7 ye ar s ol d (n =3 05 ) h ei gh t ( cm ) 12 0. 8 (5 .6 ) 10 7. 4 13 5. 0 12 5. 7 (5 .8 )* 11 2. 2 14 1. 7 11 3. 7 (3 .2 ) 10 9. 6 11 6. 3 12 3. 1 (5 .2 ) 11 6. 0 13 1. 3 12 2. 0 (6 .1 ) 10 7. 4 14 1. 7 w ei gh t ( kg ) 22 .4 (4 .0 ) 15 .5 40 .8 25 .7 (5 .5 )* 17 .2 45 .9 19 .6 (1 .2 ) 18 .9 21 .4 22 .0 (3 .2 ) 16 .6 26 .1 23 .2 (4 .6 ) 15 .5 45 .9 fa t ( % ) 15 .9 (4 .6 ) 7. 9 37 .8 17 .9 (5 .8 )* 11 .2 38 .6 14 .7 (0 .9 ) 13 .3 15 .5 17 .3 (4 .0 ) 12 .8 23 .1 16 .4 (5 .0 ) 7. 9 38 .6 tc s f ( m m ) 8. 3 (3 .4 ) 3. 0 23 .0 10 .3 (4 .0 )* 5. 3 24 .3 8. 8 (1 .7 ) 6. 5 10 .8 9. 1 (2 .5 ) 6. 0 12 .5 8. 9 (3 .6 ) 3. 0 24 .3 sc s f ( m m ) 6. 9 (2 .6 ) 3. 5 22 .0 7. 2 (4 .1 ) 3. 0 23 .0 5. 8 (1 .1 ) 4. 5 6. 8 7. 2 (2 .7 ) 5. 0 13 .3 7. 0 (3 .1 ) 3. 0 23 .0 g ro up h ei gh t ( cm ) 11 8. 0 (5 .9 ) 10 0. 8 13 5. 0 12 4. 1 (5 .9 )* 11 1. 2 14 1. 7 11 7. 2 (4 .6 ) 10 9. 6 12 5. 7 12 1. 4 (5 .7 ) 11 1. 1 13 1. 3 11 9. 6 (6 .5 ) 10 0. 8 14 1. 7 w ei gh t ( kg ) 21 .4 (4 .2 ) 13 .7 68 .6 24 .8 (5 .2 )* 16 .9 45 .9 21 .4 (8 .2 ) 16 .3 55 .3 21 .7 (3 .2 ) 16 .6 26 .1 22 .3 (4 .8 ) 13 .7 68 .6 fa t ( % ) 15 .2 (4 .4 ) 6. 5 39 .4 16 .9 (5 .5 )* 7. 3 38 .8 13 .8 (7 .2 ) 7. 6 42 .7 17 .3 (3 .7 ) 12 .8 23 .1 15 .7 (4 .9 ) 6. 5 42 .7 tc s f ( m m ) 7. 9 (3 .2 ) 3. 0 25 .0 10 .0 (3 .8 )* 4. 0 24 .3 7. 6 (5 .3 ) 4. 3 28 .5 9. 5 (3 .0 ) 5. 5 13 .3 8. 5 (3 .5 ) 3. 0 28 .5 sc s f ( m m ) 6. 8 (2 .8 ) 3. 0 30 .3 6. 5 (3 .7 ) 2. 5 27 .3 5. 9 (4 .5 ) 3. 0 24 .0 7. 1 (2 .4 ) 5. 0 13 .3 6. 7 (3 .1 ) 2. 5 30 .3 b m i 15 .3 (2 .0 ) 12 .1 38 .4 16 .0 (2 .4 )* 12 .4 26 .8 15 .5 (4 .6 ) 12 .6 35 .0 14 .6 (1 .5 5) 12 .3 17 .7 15 .5 (2 .3 ) 12 .1 38 .4 sd = s ta nd ar d de vi at io n; m in . = m in im um ; m ax . = m ax im um ; t c = tr ic ep s; s f = s ki nf ol d; s c = su bs ca pu la r; b m i = b od y m as s in de x. *p <0 .0 5 = si gn ifi ca nt d iff er en ce b et w ee n bl ac k an d w hi te le ar ne rs . 112 sajsm vol. 26 no. 4 2014 and ses. a prevalence of 11.1% of overweight (7.6%) and obesity (3.5%) was found in the total group of grade 1 learners. a significant age effect was found, indicating a significant rise in the prevalence of overweight from 6.3% in 6-year-old learners to 10.5% in 7-year-olds. obesity rates (3.6%) were lower than overweight rates in the total group, where 4.8% of 6-year-old learners and 2.3% of 7-year-old learners were obese. it could perhaps be speculated that the above results point towards a weight loss between the ages of 6 and 7 years, where some children changed from obese to overweight. as this is the first phase of a longitudinal study, subsequent assessments will show whether this is indeed an age-related trend. although the overweight statistics of 7-year-old learners were higher than in 6-year-olds, none of the 7-year-old’s in quintile 1 3 schools were obese. girls, white children and children of higher ses also had higher levels of overweight and obesity compared with the other groups. a recent review on overweight and obesity in children and adolescents in sa also confirmed that the prevalence of overweight and obesity among children and adolescents in sa is strongly dependent on age, gender and ethnicity.[17] the overall prevalence rates of overweight and obesity found in this study are lower when compared with studies conducted worldwide on similar age groups, but similar to most studies done in sa among learners of the same age.[6,7,18,19] this may be owing to different thresholds to define overweight and obesity being used in some of these studies compared with the cut-off values used in our study,[14] making direct comparisons difficult. studies done in canada, norway and america on children aged 6 11 years report the prevalence of overweight and obesity to be 6.3%, 10.1% and 20.7%, respectively.[3] the thresholds from the centers for disease control and prevention (cdc) were used in these studies, where the cdc growth charts are based on information for us children.[3] a study on french children aged 7 9 years (n=1 582), which was also based on the thresholds on the cdc growth charts, reported that 20.6% of the children were overweight and 6.4% obese.[18] padez et al.[19] undertook a study of 7 9-year-old portuguese children, which indicated that 31.5% were overweight or obese (20.3% overweight, 11.3% obese). these researchers used the cut-off points of the international obesity task force (iotf) to define overweight and obesity.[19] a study done by skelton et al.[4] in america found that 3.8% of the 2 19-year-old children who participated in the study already showed severe obesity. the majority of sa studies[6,7,20-22] have reported a similar prevalence for overweight and obesity among children of the same age group. the results of the national food consumption survey based on the iotf cut-off points, conducted on children between the ages of 1 and 8 years (n=2 894), showed that 6.7% of children could be classified as overweight and 3.7% as obese.[7] kruger et al.[22] assessed anthropometric status in sa women and children in 2005 in order to document temporal trends in selected anthropometric parameters. when the bmi cut-off points for international use[14] were used to define overweight and obesity in 1 9-year-old children, 10% nationally were overweight and 4% obese. a study on 579 primary school children between the ages of 8 and 10 years in a rural magisterial district of kwazulu-natal found that 3.1% of the children were obese. [20] in another study undertaken by jinabhai et al.[21] in kwazulu-natal on 802 children between the ages of 8 and 11 years, the incidence of overweight varied between 0.4 and 13.3%, and obesity between 0.1 and 3.7%. two sets of criteria were used by jinabhai et al.[21] to measure overweight and obesity, namely the who standard based on the 85th and 95th percentiles, and the iotf criteria. in the current study, the results further indicated a higher, although non-significant, prevalence of overweight and obesity among girls than boys in the overall group, and between the 6and 7-year-old girls compared with 6and 7-year old boys. another sa study[6] found that girls at the ages of 6 and 7 years (6 years 11.9%; 7 years 11.8%) had a higher prevalence of overweight when compared with boys (6 years 8.0%; 7 years 9.2%). armstrong et al.,[6] who also used the cut-off points of cole et al.,[14] reported similar results among 7-year-old girls and boys, where the girls (5.8%) had a higher prevalence of obesity than the boys (2.5%). the results of armstrong et al.,[6] however, differed from the results of our study with regard to 6-year-old children, where the 6-year-old boys had a higher prevalence of obesity than the girls (6.0% v. 4.1%, respectively). however, other studies in sa also report a higher prevalence of overweight and obesity among girls than among boys.[20,21] significant differences were found in the overweight and obesity prevalence rates of white and black children, indicating that white learners are significantly more overweight and obese (19.7%) than table 2. body mass index (kg/m2) of black, white, mixed ancestry, and indian boys and girls overall age all black white mixed ancestry indian mean (sd) n mean (sd) n mean (sd) n mean (sd) n mean (sd) n boys 6 years 15.6 (2.3) 250 15.3 (1.7) 168 16.1 (2.3)* 71 16.3 (6.7) 10 13.5 (0.0) 1 7 years 15.5 (2.2) 169 15.2 (1.8) 110 16.2 (2.7)* 50 16.8 (0.0) 1 14.5 (1.4) 5 group 15.5 (2.2) 420 15.3 (1.8) 278 16.1 (2.4)*† 122 16.3 (6.3) 11 14.3 (1.4) 6 girls 6 years 15.4 (2.5) 261 15.3 2.5) 186 15.7 2.4) 64 14.3 (1.4) 6 16.3 (2.1) 2 7 years 15.6 (1.9) 136 15.4 (1.7) 104 16.4 (2.5)* 29 14.6 (1.0) 3 14.3 (1.5) 3 group 15.5 (2.3) 396 15.4 (2.3) 290 15.9 (2.5)*† 93 14.4 (1.2) 9 15.1 (1.8) 5 *p<0.05 = significant overall and age-specific differences between black and white learners. † significant gender differences. sajsm vol. 26 no. 4 2014 113 black learners (8.8%). this was the case in the 6and 7-year-old groups and in the overall group. in a study on 10 15-year-old children living in the nwp of sa, kruger et al.[23] also found that white children had the highest prevalence of overweight and obesity (white 14.2%, black 7.1%, indian 6.4% and mixed ancestry 2.9%), although this study was conducted on older children. research by reddy et al.,[24] based on the national youth behaviour survey in 2002, reported similar results, where white boys and girls aged 13 19 years showed a higher prevalence of overweight and obesity than black boys and girls. very few research results are available in sa concerning overweight and obesity among other ethnic groups such as mixed ancestry and indian populations. a study in the nwp among 10 12-year-old girls indicated that 16.5% of girls were overweight and 4.9% were obese. [25] these researchers reported differences between racial groups in overweight (21.3% white, 15.81% black, 9.1% mixed ancestry, 17.4% indian) and obese (8.5% white, 4.4% black, 0% mixed ancestry, 8.7% indian) girls.[25] the limited number of mixed ancestry and indian children in our study is acknowledged as a limitation of the study, making comparisons in this regard difficult. more research is thus recommended to obtain more information on overweight and obesity trends in these ethnic groups in sa. learners in quintile 4 and 5 schools, representing schools in areas with higher socioeconomic circumstances, showed significantly higher prevalence rates of overweight in both the 6and 7-year-old groups compared with those in quintile 1 3 schools. quintile 4 schools also showed significantly higher levels of obesity compared with lower quintile schools. these results agree with the findings of several researchers,[6,7,24,26] indicating that children living in lower socioeconomic areas in sa have lower prevalence rates of overweight and obesity. steyn et al.[7] also reported that the highest prevalence of overweight and obesity among younger children (1 8 years) in sa was seen in urban areas. kruger et al.[23] reported similar findings among 10 15-yearold children, where a higher prevalence of overweight and obesity was found in urban areas and smaller households. monyeki et al.[26] reported that very few black children in rural areas of age 7 years were above the nhanes iii (third national health and nutrition examination survey) 85th percentile for bmi. therefore, it seems that sa children from higher ses have the highest rates of overweight and obesity, which is different to the findings of studies conducted in other countries such as the usa, which indicated that the highest rates of obesity and severe obesity are among children who are underserved by the healthcare system. [3,4] these studies are, however, conducted in firstworld countries, while sa is considered a developing country with high socioeconomic disparities. furthermore, researchers in india table 3. sample size and percentage of grade 1 learners (6 and 7 years) by gender, race and school type, classified as overweight or obese* normal, n (%) overweight, n (%) obese, n (%) combined ow/ob, n (%) total, n 6 years boys 220 (91.6) 11 (4.4) 10 (4.0) 21 (8.4) 250 girls 226 (86.6) 21 (8.1) 14 (5.4) 35 (13.5) 261 white 113 (81.9) 16 (11.6)† 9 (6.5)† 25 (18.1) 138 black 325 (91.8) 15 (4.2)† 14 (4.0)† 29 (8.2) 354 quintile 1 87 (90.8) 5 (5.2) 4 (4.2) 9 (9.4) 96 quintile 2 106 (93.8) 3 (2.7) 4 (3.6) 7 (6.3) 113 quintile 3 122 (96.8) 1 (0.8) 3 (2.4) 4 (3.2) 126 quintile 4 71 (78.0) 12 (13.2) 8 (8.8) 20 (22.0) 91 quintile 5 69 (81.2) 11 (12.9) 5 (5.9) 16 (18.8) 85 group 455 (89.0) 32 (6.3)† 24 (4.7) 56 (12.0) 511 7 years boys 149 (88.2) 16 (9.5) 4 (2.4) 20 (11.9) 169 girls 117 (86.0) 16 (11.8) 3 (2.2) 19 (14.0) 136 white 62 (77.5) 13 (16.3) 5 (6.3) 18 (22.6) 80 black 192 (90.1) 19 (8.9)† 2 (1.0)† 21 (9.9) 213 quintile 1 56 (94.9) 3 (5.1) 0 3 (5.1) 59 quintile 2 42 (91.3) 4 (8.7) 0 4 (8.7) 46 quintile 3 46 (93.9) 3 (6.1) 0 3 (6.1) 49 quintile 4 55 (87.3) 5 (7.9) 3 (4.8) 8 (12.7) 63 quintile 5 67 (76.1) 17 (19.3) 4(4.6) 21 (23.9) 88 group 266 (87.2) 32 (10.5)†‡ 7 (2.3) 39 (12.8) 305 group boys 378 (90.2) 27 (6.4) 14 (3.3) 41 (9.7) 419 girls 343 (86.4) 37 (9.3) 17 (4.3) 54 (13.6) 397 white 175 (80.3) 29 (13.3)†‡ 14 (6.4)†‡ 43 (19.7)† 218 black 517 (91.2) 34 (6.0) 16 (2.8) 50 (8.8)† 567 quintile 1 143 (92.3) 8 (5.2) 4 (2.6) 12 (7.8) 155 quintile 2 148 (93.1) 7 (4.4) 4 (2.5) 11 (6.9) 159 quintile 3 168 (96.0) 4 (2.3) 3 (1.7) 7 (4.0) 175 quintile 4 126 (81.8) 17 (11.0)†‡ 11 (7.1)†‡ 28 (18.1) 154 quintile 5 136 (78.6) 28 (16.2)†‡ 9 (5.2) 37 (21.4) 173 group 721 (84.1) 64 (7.5) 31 (3.6) 95 (11.1) 816 ow/ob = overweight and obesity. *international bmi cut-off points were used to determine overweight and obesity. †p<0.05. ‡effect sizes: cramér’s v=0.1+ small; 0.3++ moderate; 0.5+++large. 114 sajsm vol. 26 no. 4 2014 linked obesity among children of high ses with provision of generous pocket money, which is mostly spent on energy-dense foods. [27] researchers also concluded that 3 18-year-old children in greece spent their pocket money on high-energy, fatty and sugary foods that contributed to the development of overweight and obesity, while small amounts of pocket money were linked with healthier body weight.[28] a tuck shop truths survey conducted among 20 schools and 652 parents in the gauteng area of sa in june 2013 confirmed that more than a quarter of children are sent to school without food and have to rely on the foods sold to them at tuck shops.[29] eighty percent of these children are provided with at least r10 per day to spend at tuck shops, where high percentages of unhealthy food are sold to them. the survey also suggested that the health content of lunch boxes that are packed for children can be improved. the high overweight and obesity statistics found in quintile 4 and 5 schools in our study support the findings of this survey. conclusion more than 10% of grade 1 learners in the nwp of sa were overweight or obese, indicating that 1 in 10 school beginners is either overweight or obese when they enter the formal school system in grade 1. the prevalence of overweight was significantly higher in 7-year-olds compared with 6-year-olds, while obesity rates were slightly lower in the older children. these results can help health professionals, policymakers and child development experts to plan future strategies to address problems relating to overweight and obesity. health education curricula and physical education programmes that include physical activity, diet and behaviour modification, and which foster an enabling environment in which children can make healthy food choices, should also be implemented in schools. more research is, however, needed to obtain a better understanding of contributing factors to childhood obesity in the diverse sa population, while longitudinal research is recommended to determine if the prevalence of overweight and obesity continues to rise with increasing age. acknowledgements. this work is based on research supported by the national research foundation (nrf) of sa, the national lottery distribution fund and the focus area of phasrec, which are acknowledged for their contributions. the authors would also like to express their gratitude to the postgraduate students, research team, and the schools and learners who participated in the study. disclaimer. any opinion, findings and conclusions or recommendations expressed in this material are the opinion of the author(s) and the nrf does not accept any liability in regard thereto. references 1. hills ap, king na, armstrong tp. the contribution of physical activity and sedentary behaviours to the growth and development of children and adolescents. sports med 2007;37(6):533-545. 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[http://dx.doi. org/10.1079/phn2005849] 24. reddy sp, resnicow k, james s, et al. underweight, overweight and obesity among south african adolescents: results of the 2002 national youth risk behaviour survey. public health nutr 2008;12(2):203-207. [http://dx.doi.org/10.1017/s1368980008002656] 25. pienaar ae, bell gj, dreyer li. the incidence of obesity and developmental coordination disorder (dcd) among 1012-year-old girls of different race groups in the north west province: thusa bana study. african journal for physical health education, recreation and dance 2007;13(1):221-237. 26. monyeki kd, van lenthe fj, steyn np. obesity: does it occur in african children in a rural community in south africa? int j epidemiol 1999;28(2):287-292. 27. raychaudhuri m, sanyal d. childhood obesity: determinants, evaluation, and prevention. indian j endocrinol metab 2012;16(suppl 2):s192-s194. [http://dx.doi. org/10.4103/2230-8210.104037] 28. grammatikopoulou mg, galli-tsinopoulou a, daskalou e, et al. is pocket money an indicant of dietary intake and obesity? arch dis child 2008;93(suppl 2):pw4. 29. tuck shop truths study reveals poor nutritional offerings. http://www.bizcommunity. com/article/196/329/98197.html (accessed 13 june 2013). original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license physical and physiological profile of u18, u19, u21 and senior elite netball players cj sinclair, 1 ma; f coetzee, 1 phd; r schall, 2 phd 1 department of exercise and sports sciences, faculty of health sciences, university of the free state, bloemfontein, south africa 2department of mathematical statistics and actuarial science, faculty of natural and agricultural sciences, university of the free state, bloemfontein, south africa corresponding author: c j sinclair (jonescj@ufs.ac.za) netball is a team sport with a high level of participation in the commonwealth, in particular in the united kingdom, australia, south africa and new zealand (nz).[1] in south africa (sa), netball is played in schools, clubs and at provincial level, with approximately half a million players in schools and 9 700 adult players.[2] netball is a popular women' s sport, and in south africa it receives government support to enhance talent identification and sport performance.[3] limited research has been done internationally that profiles the physical characteristics and fitness levels of netball players. no research describing the physical and physiological profiles of u18, u19, u21 and senior elite netball players in sa has been previously conducted.[4,5] therefore, this is the objective of the present study, and the data could provide information for coaches, players and netball organisations with regard to sports progression and talent identification.[9] previous research[10] has indicated that more comprehensive studies are required to ensure that netball players undergo relevant conditioning and technique training to meet the specific demands of the sport. various fitness tests can be performed to determine a netball player's physiological profile.[6–9] such tests will identify the player' s strengths and weaknesses, providing strength and conditioning coaches with information on the effectiveness of their training methods. the significance of this study is that the results may serve to validate current physical fitness assessments or indicate the need for different assessment and training methods for netball players. the authors studied players from the free state (fs) high school’s u18a league and from the fs u19, fs u21 and fs senior netball teams subjecting them to a comprehensive battery of fitness tests. a secondary objective was to compare the fitness profiles of players in this study with fitness normative data for specifically sa and nz netball. methods participants this cross-sectional, descriptive study included a total of 96 participants of which 77 completed all the tests. nineteen participants were excluded from the study due to injuries at the time of fitness testing. all participants were registered members of one of the following teams: fs high school u18a league, fs u19 and fs u21 teams, and fs senior team. approval for the study was obtained from the health sciences research ethics committee, ufs (ufs-hsd2017/0014). before testing, each participant provided an informed consent form to the researchers and received an information document which provided the details of the research study. testing procedures all teams were tested at the beginning of the 2017/2018 netball season at the exercise and sport science centre of the university of the free state (ufs) in bloemfontein, south africa. tests took place in the mid-afternoon over a two-day period. a logical sequence of tests was compiled to determine the correct order the tests should follow and that the necessary duration of rest periods between tests was ensured for test reliability.[11] the following measurements and tests were performed on the first day from non-fatiguing tests: anthropometric measurements anthropometric measurements according to the international standards for anthropometric assessment (isaa);[12] background: physical and physiological profile data for elite netball players in south africa and internationally are limited but are necessary for conditioning programme information. objective: to determine the physical and physiological profiles of u18, u19, u21 and senior level elite netball players at provincial level in the free state, south africa. the information provided is by age group and playing position. the fitness of the players for south african and new zealand netball is also given using the fitness normative data (norms). methods: this cross-sectional, descriptive study consisted of 77 elite south african netball players. anthropometric measurements were taken according to international standards. fitness tests included the star execution balance test, standing broad jump, doubleand single-leg vertical jump, yo-yo intermittent recovery level 1(ir1) test, sprints over 5, 10 and 40 m, horizontal pull-ups and press-ups, the prone bridge test and anaerobic octorepeater tests with 10 m and 20 m repeated shuttle sprints. in keeping with the descriptive nature of the study, descriptive statistics were calculated for numerical data by age group and playing position. results: players generally did not meet the accepted fitness standards in the following areas: press-ups (all age groups), horizontal pull-ups (senior and u21), standing broad jump (senior and u21), vertical squat jump (senior and u21), 5 m and 10 m sprints (senior and u21); anaerobic octorepeater (senior players), and the aerobic yo-yo ir1 test (all age groups). conclusion: strength and conditioning coaches should develop training programmes to address fitness areas where players do not meet the international standards. keywords: sport, fitness tests, body composition, performance tests, fitness norms s afr j sports med 2020;32:1-7. doi: 10.17159/2078-516x/2020/v32i1a6545 mailto:jonescj@ufs.ac.za http://dx.doi.org/10.17159/2078-516x/2020/v32i1a6545 https://orcid.org/0000-0002-0393-3100 https://orcid.org/0000-0002-4145-3685 https://orcid.org/0000-0002-3652-3976 original research sajsm vol. 32 no. 1 2020 2  body mass and stature  the sum of six skinfolds (triceps, subscapular, suprailliac, abdominal, supraspinale, thigh and calf). star execution balance test (sebt) the star execution balance test (sebt) which determined the balance and postural control in a dynamic test that is functional in netball.[1] during this test, the participant stands with their hands on their iliac crest centred in a "star sign". the participant is then instructed to reach out with one foot while balancing on the opposite leg. each participant is asked to reach out in eight different directions at 45° increments from the centre of the "star sign". the participant has to reach to the furthest possible point with the distal part of their foot while maintaining their balance, and to return to the start position after each reach position. the distance reached is recorded on the measuring tape that is attached to the star sign. the test is performed on both legs.[13] standing broad jump and doubleand single-leg vertical jump the standing broad jump test of explosive horizontal leg power and doubleand single-leg vertical squat jump tests of vertical explosive power which determines the participant’s explosive horizontal leg power. the participant was required to stand behind a marked line with feet shoulder width apart on the ground. the participant had to stand without swaying or rocking their feet but with knees bent, and only swinging their arms. they then had to perform a two-foot forward drive take-off, landing with both feet on the ground simultaneously. the maximum distance achieved via the best of three trials was recorded.[8] before the doubleand single-leg vertical squat jump test, the participant was instructed to stand next to the vertec vertical jump tester and reaching up, touch the highest vane possible with one hand while maintaining both feet firmly on the ground. this height was recorded as the participant's standing reach height. participants performed the best of three trials with sufficient rest between them. the maximal vertical jump was determined as the difference between the maximum height jumped and standing reach height.[8] the reliability and intraclass correlation coefficient (icc) is excellent for the double-leg vertical jump (0.94) and coefficient of variation (cv) 3.3 cm. the single-leg vertical jump has also an excellent reliability of icc of 0.96 and 0.91 for the right and left legs respectively, with cv of 4.2 cm.[14] yo-yo intermittent recovery level 1(ir1) test the yo-yo ir1 aerobic test evaluates aerobic fitness over a period of time, which is according to the level deducted from the cd playing. cones marked out three lines: 5 m (recovery), 0 m (start line) and 20 m (turn line). the participant started on or behind the start line (0 m) and began running 20 m when instructed to by the recorded audio. the participant then turned and returned to the starting point. the participant must then complete the active recovery period (5 s) during which they must walk or jog around the other (5 m) cone and return to the starting point. a warning was given when the participant did not complete a successful out and back shuttle and recovery shuttle in the allocated time. the participant was then told to stop the test. a participant's final yo-yo score was the last successful shuttle completed.[8} the following tests were performed on the second day: horizontal pull-ups, press-ups and the prone bridge test horizontal pull-up and press-up tests to evaluate pulling, pushing strength and endurance, and the prone bridge (plank) to test core endurance. a weight lifting bar was placed in a squat or power rack. the participant's arms had to be fully extended, with their body just off the ground. the participant gripped the bar, which was slightly wider than shoulder width, by means of an overhand grasp. their feet were flat on the floor, with knees bent at a 90° angle. their hips were then lifted so that their body was straight and their arms fully extended. they then pulled their body towards the bar until their chest touched it (nipple line aligned with bar). they then lowered themselves back down until their arms were again fully extended. the participant continued doing as many repetitions as possible until they could no longer touch the bar. the examiner recorded the total amount of correct repetitions completed.[8] the press-up evaluates the participant's upper body’s pushing and endurance strength. the start was in the plank position with their hands and knees off the ground. the examiner then placed a closed fist in line with the participant's chest. they then lowered their body so that it was in line with the fist and thereafter pushed up again until their arms were once more fully extended. the total number of correct repetitions were counted.[8] as previously mentioned, the prone bridge (plank) evaluates the participant's core strength and endurance. the participant started in the plank position, with elbows on the ground, feet approximately hip distance apart, knees off the ground and the body straight, with no arching of the back. the head and neck faces towards the ground, keeping the whole body aligned. the participant was required to maintain the plank position for as long as possible, maintaining normal breathing. once the participant can no longer keep their body straight, i.e. they start to excessively arch or curl their back, the test is stopped. the total time that the participant maintained a correct plank position was recorded.[8] sprints sprints over 5, 10 and 40 metres (m) respectively to test acceleration and speed. the aim of this test was to determine the acceleration and rapidity of each participant in sprinting. electronic timing lights were placed at the start at distances of 5, 10 and 40 m to ensure that there was enough space past the 40 m marker for participants to decelerate and stop. each participant started from a stationary position with one foot behind the start line, ensuring there was no rocking or swaying prior to the start. an adequate warm-up was provided (5 minutes light jog, 10 minutes dynamic stretches) before the test to minimise risk of injury. each participant had to complete three trials with original research 3 sajsm vol. 32 no. 1 2020 approximately two–three minutes of rest between attempts, and the best score was used.[8] octorepeater tests the octorepeater anaerobic fitness test, consisting of 10 m and 20 m repeated shuttle sprints, mimics the game of netball. this test assesses the player's ability to perform repeated maximal sprints that incorporate a change of direction. each participant completes four sets of 2 x 20 m and four sets of 4 x 10 m sprints respectively, alternating between the 2 x 20 m and 4 x 10 m sprints, with 25-second rest intervals between each 2 x 20 m and 4 x 10 m set. the participant first completes the 2 x 20 m followed by the 4 x 10 m sprint. the fatigue index is then calculated as 100·(average time best time)/(best time), where "average time" is the average time achieved in the four sets of 2 x 20 m and 4 x 10 m sprints, and "best time" is the sum of the best times achieved in the four sets of 2 x 20 m and 4 x 10 m sprints, respectively.[8] statistical analysis in keeping with the descriptive nature of the study, descriptive statistics were calculated for numerical data for all players in the sample. descriptive statistics were also calculated by age group (u18, u19, u21 and senior players) and playing position. potential differences between the age groups and playing positions were tested using one-way analysis of variance, and the associated p-value from the ftest was determined in tables 1, 2 and 3. because of the relatively large number of tests performed and the resulting multiplicity issues, these p-values should be interpreted descriptively. for the same reason, no post-hoc tests were conducted. data analysis was performed using sas version 9.4.[15] results anthropometric measurements the mean body weight of u18, u 21 and senior players was 66.9 kg, 70.4 kg and 75.3 kg, respectively, suggesting a trend that body weight increases with age (table 1). however, the mean weight of the u19 group was 76.7 kg, which was inconsistent with the pattern, although this could have been due to the small size (n=5) of the u19 group. similarly, table 1 shows a trend that height increases with age. the differences in weight (p=0.046) and height (p=0.011) between the age groups were statistically significant at the conventional significance level of 0.05. however, the body mass index (bmi) p=0.674) and fat percentage (p=0.078) did not differ significantly between age groups. body weight, height, body fat percentage and bmi varied according to overall playing position. the goal shooter (gs) had the highest mean body weight of 80.1 kg, followed by the goalkeeper (gk) 77.7 kg and goal attacker (ga) 74.2kg. the gs is the tallest player 181.2 cm compared to the gk and ga that are each the same height of 175 cm. overall, the differences in weight and height between playing positions were statistically significant (both p<0.0001), while bmi (p=0.416) and fat percentage (p=0.381) did not differ significantly. tables 2, 3 and 4 represent the results of the fitness tests that formed part of the profiling of physiological data of the netball players and the percentage of players that were compliant with the sa and nz standards[8,19] (table 4). muscular strength endurance and explosive power tests the variability in the muscular strength endurance and explosive power tests (table 2) was generally high. the coefficient of variation (mean divided by standard deviation (sd)) of these measurements was generally 30% or higher. none of the prone bridge, press-up, horizontal pull-up, double or single-leg vertical squat jumps differed significantly between age groups (table 2). of the explosive power tests, only the standing broad jump differed significantly (p=0.033) between age groups, with the two younger age groups achieving slightly higher values, although these small differences of 4–7 cm did not appear to be of practical relevance. in all these tests, only the mean number of press-ups differed significantly (p=0.032) between playing positions (which could have been due to the low mean for the ga). however, the mean differences of approximately one press-up again seemed to be of small practical relevance. with regard to explosive power, only the single-leg vertical squat jump differed significantly between playing positions (p=0.044). except in the case of the press-up, the majority of participants (80% or more) in the two younger age groups met the minimum standards set by sa and nz netball for the respective age groups (table 4).[8,19] by contrast, notably fewer of the senior and u21 players met the standards for these tests – generally below 50%. speed, aerobic and anaerobic tests of all of speed, aerobic and anaerobic tests (table 3), only the yo-yo ir1 test showed statistically significant differences (p=0.020) between the age groups, suggesting a trend for higher mean values as age increases. differences in the fatigue index between age groups were borderline insignificant (p=0.060), with the senior players (mean of 8.5%) exhibiting higher values than the other age groups (mean between 3.8% and 5.8%). none of these tests showed significant differences between playing positions. only a small number of players in all the age groups met the minimum standards for the 5 m and 10 m sprints and the yoyo ir1 test. by contrast, most players in the younger age groups met the standard for the fatigue index, compared to only 45.5% of senior players. discussion comparative data on the physical and physiological profiles of u18, u19, u21 and senior elite netball players are not available for sa, and only a limited number of international studies have been conducted.[7,9,17] to these authors’ knowledge, this is the first study to investigate and statistically compare the physical and physiological profiles of the various age groups from u18 to senior level of elite netball players in sa. the overall mean body weight of netball players in this study original research sajsm vol. 32 no. 1 2020 4 table 1. anthropometric measurements of elite netball players according to age group and playing position age group playing position variable statistic senior (n=11) u21 (n=16) u19 (n=5) u18 (n=45) f-test (df=3,73) gs (n=11) ga (n=4) wa (n=15) c (n=15) wd (n=14) gd (n=7) gk (n=11) f-test (df=6,70) all (n=77) age (yr) mean 20.9 19.7 19.0 16.6 18.2 18.5 17.8 18.0 18.5 17.4 18.0 18.1 sd 1.6 0.9 0.0 0.7 2.0 3.1 1.5 1.6 2.6 1.5 2.2 2.0 min 18 18 19 15 16 16 16 15 15 16 15 15 max 23 21 19 18 22 23 21 21 22 20 22 23 mass (kg) mean 75.3 70.4 76.7 66.9 f=2.80; p=0.046 80.1 74.2 63.3 64.7 66.8 66.2 77.7 f=6.20; p<0.0001 69.5 sd 10.7 6.7 17.1 10.9 10.6 7.3 6.9 8.00 9.7 8.8 12.0 11.0 height (cm) mean 176.7 172.7 172.8 168.6 f=3.97; p=0.011 181.2 175.0 165.5 167.6 167.9 170.4 175.0 f=9.00; p<0.0001 170.9 sd 7.8 5.2 5.9 8.5 5.9 5.7 6.8 4.5 8.2 7.9 5.7 8.1 bmi (kg/m2) mean 24.1 23.6 25.2 23.5 f=0.51; p=0.674 24.5 24.3 23.1 23.0 23.8 22.7 25.2 f=1.03; p==0.416 23.7 sd 2.4 2.4 4.1 3.2 4.1 2.5 1.7 2.4 3.6 1.7 3.5 3.0 body fat (%) mean 28 28.2 32.9 27.1 f=2.36; p=0.078 30.0 29.6 27.3 26.3 27.1 26.4 29.4 f=1.08; p=0.381 27.8 sd 4.4 4.5 6.6 4.7 4.4 3.8 4.8 5.0 4.6 2.1 6.5 4.84 p-value calculated from the f test of one-way analysis of variance (anova). sd, standard deviation; bmi, body mass index; f, f-statistic; p, p-value; df, degrees of freedom (numerator, denominator); gs, goal shooter; ga, goal attack; wa, wing attack; c, centre; wd, wing defence; gd, goal defence; gk, goal keeper. table 2. muscular strength endurance and explosive power tests of u18, u19, u21 and senior elite netball players age group playing position variable statistic senior (n=11) u21 (n=16) u19 (n=5) u18 (n=45) f-test (df=3,73) gs (n=11) ga (n=4) wa (n=15) c (n=15) wd (n=14) gd (n=7) gk (n=11) f-test (df=6,70) all (n=77) prone bridge (s) % sa 55 37.5 100 80 f=1.43 p=0.240 73 75 60 80 36 86 91 f=0.92 p=0.484 69 % nz 55 37.5 100 93 73 86 87 93 64 86 91 81.8 mean 116.0 97.4 105.0 127 109.1 116.0 118.1 123.1 98.3 115.6 144.6 117.6 sd 45.0 36.0 23.3 57.6 65.8 23.3 50.5 38.4 36.3 10.4 75.9 51.1 press-up (n) % sa/ nz 9 13 0 27 f=0.36 p=0.785 9 0 33 7 14 29 36 f=2.47 p=0.032 20 mean 8.9 9.8 7.0 10.4 11.7 2.0 12.9 11.1 10.2 10.4 11.7 9.9 sd 6.9 7.3 4.7 8.5 4.9 1.8 9.9 7.8 7.5 6.0 6.0 7.8 horizontal pull-up (n) % sa/ nz 46 56 80 82 f=0.66 p=0.580 73 75 60 73 57 86 91 f=0.62 p=0.715 71 mean 12.5 11.1 11.2 13.2 10.9 11.3 12.5 14.6 11.6 12.9 13.0 12.5 sd 4.3 6.5 4.9 5.5 5.0 3.0 5.5 6.7 6.4 4.2 4.8 5.5 standing broad jump (m) % sa 46 81 100 84 f=3.07 p=0.033 46 25 93 87 86 86 91 f=2.07 p=0.068 79 % nz 9.1 18.8 20.0 17.8 0.0 0.0 13.3 26.7 14.3 28.6 27.3 16.9 mean 1.83 1.82 1.87 1.89 1.8 1.6 1.8 1.8 1.6 1.8 1.8 1.8 sd 0.2 0.2 0.2 0.2 0.2 0.3 0.3 0.2 0.2 0.2 0.2 0.2 double-leg vertical squat jump (cm) % sa/ nz 46 63 100 69 f=0.96 p=0.418 54.6 25 60 80 57 86 82 f=1.34 p=0.251 66 mean 46.4 43.2 45.8 43.3 45.3 42.3 43.9 47.2 41.5 43.9 41.7 43.9 sd 5.3 7.0 5.7 6.2 6.1 4.8 2.5 6.1 6.7 7.1 6.1 6.2 single-leg vertical squat jump (cm) % sa/ nz 46 25 100 80 f=1.82 p=0.151 55 50 67 73 43 71 91 f=2.30 p=0.044 65 mean 36.6 33.7 39.4 34.3 36.0 24.3 33.7 39.8 34.0 33.5 32.4 34.8 sd 6.7 4.7 4.0 5.8 5.7 1.5 2.8 5.4 7.2 5.4 5.4 5.8 p-value calculated from the f test of one-way analysis of variance (anova) %sa, percentage of players compliant with the minimum standards of south africa; %nz, percentage of players compliant with the minimum standards of new zealand; %sa/nz, percentage of players compliant with the minimum standards of both south africa and new zealand; sd, standard deviation; bmi, body mass index; f, f-statistic; p, p-value; df, degrees of freedom (numerator, denominator); gs, goal shooter; ga, goal attack; wa, wing attack; c, centre; wd, wing defence; gd, goal defence; gk, goal keeper. original research 5 sajsm vol. 32 no. 1 2020 table 3. speed, aerobic and anaerobic tests of u18, u19, u21 and senior elite netball players age group playing position variable statistic senior (n=11) u21 (n=16) u19 (n=5) u18 (n=45) f-test (df=3,73) gs (n=11) ga (n=4) wa (n=15) c (n=15) wd (n=14) gd (n=7) gk (n=11) f-test (df=6,70) all (n=77) 5 m sprint (s) % sa 0 0 0 20 f=0.30 p=0.827 9 25 20 7 14 0 9 f=1.15 p=0.343 12 % nz 0 0 0 9 9 0 7 7 0 0 9 5 mean 1.3 1.3 1.3 1.3 1.3 1.3 1.2 1.2 1.3 1.3 1.3 1.3 sd 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 10 m sprint (s) % sa 0 0 0 18 f=0.20 p=0.898 9 0 27 13 0 14 0 f=1.78 p=0.117 10 % nz 0 0 0 4 9 0 7 0 0 0 0 3 mean 2.1 2.2 2.2 2.1 2.2 2.2 2.1 2.1 2.2 2.1 2.2 2.2 sd 0.1 0.1 0.1 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 40 m sprint (s) % nz 100 100 100 95.6 f=0.18 p=0.908 91 100 100 100 100 100 91 f=1.26 p=0.287 97 mean 6.5 6.5 6.7 6.5 6.8 6.6 6.6 6.3 6.6 6.5 6.6 6.5 sd 0.4 0.4 0.3 0.6 0.9 0.4 0.4 0.2 0.4 0.5 0.5 0.5 total time (s) %sa/nz 0 0 80 56 f=0.37 p=0.774 9 0 13 18 11 2 11 f=1.62 p=0.155 38 mean 85.22 84.38 82.43 83.35 86.78 88.16 84.21 81.32 82.91 86.06 81.54 83.77 sd 6.60 3.74 2.63 7.29 9.50 8.53 6.13 4.35 5.78 5.45 4.01 6.34 fatigue index (%) %sa/nz 46 100 100 84 f=2.57 p=0.060 82 75 80 93 79 71 99 f=1.11 p=0.365 83 mean 8.5 4.9 3.8 5.8 7.0 4.7 7.6 4.4 5.1 5.8 6.1 5.9 sd 5.4 1.5 1.3 4.2 4.0 3.0 6.1 1.9 2.0 3.8 4.4 4.0 yo-yo (level) % sa 0 13 0 7 f=3.51 p=0.0195 9 0 0 0 0 29 18 f=1.39 p=0.2300 7 % nz 0 0 0 7 9 0 0 0 0 14 9 4 mean 15.2 15.00 14.8 14.3 14.1 14.5 14.5 15.2 14.4 15.00 14.6 14.6 sd 0.6 0.9 0.5 1.1 1.2 1.6 1.2 0.7 1.0 1.3 0.7 1.1 p-value calculated from the f test of one-way analysis of variance (anova). %sa, percentage of players compliant with the minimum standards of south africa; %nz, percentage of players compliant with the minimum standards of new zealand; %sa/nz, percentage of players compliant with the minimum standards of both south africa and new zealand; sd, standard deviation; bmi, body mass index; f, f-statistic; p, p-value; df, degrees of freedom (numerator, denominator); gs, goal shooter; ga, goal attack; wa, wing attack; c, centre; wd, wing defence; gd, goal defence; gk, goal keeper. table 4. minimum fitness standards of south africa and new zealand elite netball players test country senior u21 u19 & u18 gk/gs ga/gd wa/wd/c gk/gs ga/gd wa//wd/c gk/gs ga/gd wa/wd/c prone bridge (s) sa 90 105 120 90 105 120 60 60 90 nz 120 120 120 90 90 90 60 60 60 press-ups (n) sa/nz 20 25 25 15 20 20 15 15 15 horizontal pull-up (n) sa/nz 15 15 15 10 10 15 5–8 8–10 10 standing broad jump (m) sa 1.90 1.90 1.90 1.70 1.70 1.70 1.50 1.50 1.50 nz 2.10 2.10 2.10 2.00 2.00 2.00 1.90 1.90 1.90 double-leg vertical squat jump (cm) sa/nz 50 50 45 45 45 40 40 40 40 single-leg vertical squat jump (cm) sa/nz 40 40 35 35 35 35 30 30 30 5 m sprint (s) sa 1.10 1.10 1.10 1.10 1.10 1.10 1.15 1.15 1.15 nz 1.08 1.08 1.08 1.10 1.10 1.10 1.12 1.12 1.12 10 m sprint (s) sa 1.90 1.90 1.90 1.95 1.95 1.95 2.00 2.00 2.00 nz 1.85 1.85 1.85 1.90 1.90 1.90 1.95 1.95 1.95 40 m sprint (s) nz 7.30 7.30 7.30 7.35 7.35 7.35 7.40 7.40 7.40 fatigue index (%) sa/nz 5–8 5–8 5 5–8 5–8 5–8 10 10 5–8 yo-yo (level) sa 15.5 16.5 17.5 15.3 16.3 17.3 15.1 16.1 17.1 nz 16.1 17.5 18.5 15.5 16.5 17.5 15.1 16.1 17.1 gs, goal shooter; ga, goal attack; wa, wing attack; c, centre; wd, wing defence; gd, goal defence; gk, goal keeper; sa, south africa; nz, new zealand. original research sajsm vol. 32 no. 1 2020 6 was 69.5 kg, which was similar to a study investigating female u19 players that reported a mean weight of 69.8 kg.[17] another study reported a mean weight of 68.8 kg for netball players aged 18 -25 years.[10] the overall mean height of players in this study was 170.9 cm, which was similar to a study conducted on junior and elite senior malaysian netball players (170.8 cm),[6] as well as a study on players with a mean age of 15.4 years and mean height of 170.0 cm.[18] the current study found the overall fat percentage to be 27.8% and the overall bmi to be 23.7 kg/m2. this was in contrast to other studies which found netball players to be notably leaner, such as the malaysian netball players (fat percentage 24.5%),[6] while two other studies reported a mean bmi of 22 kg/m2 and 21.9 kg/m2,respectively.[9,17] however, the low bmi values in previous research could be attributed to the mean age of players (149 and 15.417 years, respectively) being lower than in this present study. here the mean number of press-ups, namely 9.9, was higher than in a study on u19 nz secondary school netball players who achieved only 7 repetitions.[18] however, the fitness norms for nz[8] and sa[19] for u17 to senior elite players specify between 15 and 25 repetitions, and overall, only 19.5% of players met those norms. furthermore, the overall mean number of repetitions of horizontal pull-ups was 12.5 in the current study, whereas fitness norms range from 5 to 15 repetitions for u17 to senior elite players[8,19], with 71.4% of players meeting the norm. specifically, the findings regarding press-ups therefore, suggest deficits in upper body strength among the players in this present study. upper body strength is vital for the player to produce enough power to throw the ball with increased speed and power to her teammate. in the current study, the overall mean prone bridge test score was 117.6 s, compared to u19 nz secondary school players who only achieved 59.4 s,[18] which is notably lower than in this study. norms for the various countries range between 60 and 120 s,[8,19] which were met by 69% (sa norm) and 82% (nz norm) of players respectively. these results might suggest that a higher emphasis on core conditioning might be necessary. in this present study, the overall mean value for the standing broad jump (horizontal explosive power) was 1.75 m, whereas a nz study reported 1.82 m for u17 and 1.69 m for u19 secondary school players.[18] the norms for nz and sa range between 1.70 and 2.10 m from u17 to senior elite players,[8,19] and these were met by 79% (sa norm) but only 17% (nz norm) of players. with regard to vertical explosive power, this study found the overall mean values of 43.9 cm for the double-leg vertical squat jump and 34.8 cm for the single-leg vertical squat jump. australia's norms for u17 to senior national team players are 43.9 cm to 46.4 cm.[16] the norms for nz and sa range from 40 cm to 50 cm for the double-leg vertical squat jump and 30 cm to 40 cm for the single-leg vertical squat jump test for u17 to elite level players,[8,19] with only about two-thirds of sa players meeting the relevant norm. a lack of explosive power can result in a player failing to retain the ball when jumping up or leaping forward to catch an oncoming ball. additionally, in table 2 the c had the most (dl 47.2 cm; sl 39.8 cm) explosive power with the doubleand single-leg squat jump, while the gk the least (dl 41.7 cm; sl3 2.4 cm). this is similar to results found by thomas et al.[20] where the c jumped higher than shooters or defenders. the mean time for the 5 m sprint in this study was 1.27 s overall, which was 0.04 s slower than the mean of 1.23 s reported for a sample of a similar age group in australia.[16] the norms for nz and sa range from 1.15 s 1.08 s for u17 to senior level players.[8,19] overall, only 12% and 5% of players met these norms. in the present study, the overall mean time achieved for the 10 m sprint was 2.15 s, which was notably slower than the norms which range from 1.95 s to 1.85 s[8] for nz and from 2.00 s to 1.90 s for sa.[19]. accordingly, 10% and 3% of players met these norms. previous research reported a mean time of 2.05 s for the 10 m sprint for players from u17 to senior level.[16] these results suggest that players in the current study were too slow in the 5 m and 10 m sprints. the octorepeater is a test that mimics the demands of netball match play of constant short bursts of speed (sprints) and constant changes in direction. the overall mean time for eight maximal sprints with 25 s intervals in the current study was 83.77 s while the norm for nz and sa for u17 to senior level players ranges from 85 s to 70 s.[8,19] the fatigue index indicates how quickly the player decreases in speed or fatigues over the eight sprints. it provides an indication of the anaerobic capacity of a player when executing short bursts of speed during match play. the overall mean fatigue index in the current study was 5.9%, compared to nz and sa norms of between 5% and 8%.[8,19] only approximately half of the senior netball players in the current study met these norms, while most of junior players did. the overall mean score for the yo-yo ir1 test was level 14.6, in comparison with both the nz and sa (level 15.1 – level 17.5) norms of level 15.1– 18.5 and level 15.1–17.5, respectively.[8,19] only 7% and 4% of players respectively met these norms. thus the yo-yo iri test results suggest that the aerobic fitness levels of the players in the current study did not meet international norms. practical application the findings in this study suggest that the study population did not meet, or only partially met, national and international norms in the various fitness areas of the physiological profiling of netball players. furthermore, this study’s results study show that there are differences in the physical and physiologic characteristics in the different playing positions and age groups of elite netball players. fitness for netball cannot be determined by a single parameter because the game demands a large number of physical and physiologic capabilities which are presented in this study. successful play at elite level in netball depends on how individuals knit together into a complete unit. thus the combination of physical and physiologic characteristics may vary from player to player or in the different positions in the game. therefore, based on the results of this study, it is recommended that increased emphasis on the following training modalities should be considered: endurance strength in the upper body; vertical and horizontal explosive power, and explosive speed over short distances. according to thomas et original research 7 sajsm vol. 32 no. 1 2020 al.[18] greater lower limb relative strength is required to overcome the inertia of body mass and improve a player's ability to accelerate and decelerate during certain movements, such as jumping, sprinting and changing in direction, thereby reducing the risk of injury and enhancing performance. additionally, high-intensity training modalities, such as repeated short (10 s – 1 min) to long (2–3 min) bouts of highintensity shuttle running, interval training which improves aerobic endurance, anaerobic capacity, and maximum aerobic speed.[18] çiçek et al.[21] provided evidence that aerobic training, such as 2 km time trials, will improve forced vital capacity, forced expired volume in one second vo2max (ml/kg/min). conclusion conditioning coaches can use this information to determine which type of profile is needed for a specific position or age group. experienced netball coaches can use this information in the process of designing a training programme to maximise the fitness development of netball players. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. acknowledgements: dr daleen struwig, medical writer/editor, faculty of health science, university of the free state, for the technical and editorial preparation of the manuscript. author contributions: c sinclair collected the data and wrote the initial research paper on which the article is based. ff coetzee analysed data, wrote and approved the final draft. r schall performed the statistical analysis, contributed to writing and approved the final draft. references 1. reid da, vanweerd rj, larmer pj, et al. the inter and intra rater reliability of the netball movement screening tool. j sci med sport 2015;18(3):353–357. [doi. 10.1016/j.jsams.2014.05.008] 2. venter re, fourie l, ferreira s, et al. physical and physiological profiles of boland netball players. s afr j sports med 2005;17(2):3–7. [http://dx.doi.org/10.17159/5082] 3. pillay t, frantz jm. injury prevalence of netball players in south africa: the need for injury prevention. s afr j physiother 2012; 68(3):7–10. [https:// doi.org/10.4102/sajp.v68i3.17] 4. paz ga, gabbett tj, maia mf, et al. physical performance and positional differences among young female volleyball players. j sports med phys fitness 2017;57(10):1282–1289. [doi: 10.23736/s0022-4707.16.06471-9] 5. booysen mj, bentel d, harry k, et al. anthropometric variables and physical fitness characteristics of male south african semi-professional footballers. s afr j res sport ph 2018;40(2):11–21. 6. soh sg, soh kl, sofian of, et al. body fat and somatotype among malaysian school netball players by playing performance. asia j phys educ recreat 2009;15(1):56–60. 7. fox a, spittle m, otago l, et al. activity profiles of the australian female netball team players during international competition: implications for training practice. j sports sci 2013;31(14):1588–1595. [doi: 10.1080/02640414.2013.792943] 8. netball new zealand. netball new zealand fitness testing guidelines & protocols. players & umpires. auckland: netball new zealand, 2014. https://studylib.net/doc/8650080/nnzfitness-testing-guidelines-protocols-2014 (accessed 1 february 2019). 9. taylor l, lander p. adolescent netball players normative data and physical performance profiles. new zealand physical educator 2018;51(1):20–24. 10. ferreira ma, spamer ej. biomechanical, anthropometrical and physical profile of elite university netball players and the relationship to musculoskeletal injuries. s afr j res sport ph 2010;32(1):57–67. 11. baechle tr, earle rw. essentials of strength training and conditioning. 3rd ed. champaign, il: human kinetics, 2008: 255–256. 12. stewart a, marfell-jones m, international society for advancement of kinanthropometry. international standards for anthropometric assessment. lower hutt, nz: international society for advancement of kinanthropometry, 2011. 13. reiman mp, manske rc. functional testing in human performance: 139 tests for sport, fitness and occupational settings. champaign, il: human kinetics, 2009: 108–109. 14. gonzalo-skok o, serna j, rhea mr, marin pj. relationships between functional movement tests and performance tests in young elite male basketball players. int j sports phys ther 2015; 10(5):628–638. [pmcid: pmc4595916] 15. sas institute inc. sas/stat 14.3 user's guide: high performance procedures. cary, nc: sas institute inc., 2017. pg nos? 16. taylor k-l, bonetti d, tanner r. protocols for the physiological assessment of netball players. canberra: australian institute of sport, 2014. https://www.clearinghouseforsport.gov.au/__data/assets/file/0 004/623362/netball_national_protocols_np_netball_v2.1_201 4.pdf (accessed 1 february 2019). pg nos? 17. thomas c, ismail kt, comfort p, et al. physical profiles of regional academy netball players. j trainol 2016;5(2):30–37. [http://dx.doi.org/10.17338/trainology.5.2_30] 18. thomas c, comfort p, jones pa, et al.. strength and conditioning for netball: a needs analysis and training recommendations. strength cond j 2017;39(4):10–21. [doi: 10.1519/ssc.0000000000000287] 19. netball south africa. pretoria: netball south africa, 2016. http://www.netball-sa.co.za (accessed 1 february 2019). is this title correct? 20. thomas c, ismail kt, simpson r, et al. physical profiles of female academy netball players by position. j strength cond res 2019;33(6):1601–1608. [doi: 10.1519/jsc.0000000000001949] 21. cicek g, güllü a, güllü e, et al. the effect of aerobic and core exercises on forced vital capacity. phys cult sport stud res 2018; 77:41–47. [doi: 10.2478/pcssr-2018-0005] https://studylib.net/doc/8650080/nnz-fitness-testing-guidelines-protocols-2014 https://studylib.net/doc/8650080/nnz-fitness-testing-guidelines-protocols-2014 original research 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license the lateral batting backlift technique: is it a contributing factor to success for professional cricket players at the highest level? m h noorbhai,1 ba, bspsc (hons), mphil (biokinetics), phd (exercise science), t d noakes,2 mbchb, md, dsc, phd, facsm, ffsem (uk), ffsem (ire) 1 department of human movement science, faculty of health sciences, university of fort hare, alice, south africa 2 division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, cape town, south africa corresponding author: m h noorbhai (habib.noorbhai@gmail.com) the mechanics of the backlift in cricket batting are poorly understood.[1] qualitative biomechanical analyses of movement in sports are key to its investigation.[2] such a mode of investigation can provide important insights into the biomechanics of technique in sports.[3] cricket batting is complex with different variables such as the grip, stance, initial movement, backlift, downswing and follow through.[4] an important component of the overall batting technique is the backlift, a technical component of batting that has defied the traditional attempt to constrain its motion to the linear plane.[4,5] the most proficient run-scorers of the game lift the bat from the region of the slips, often causing the downswing path of the bat to deviate from its upswing. devising a qualitative biomechanics model of the backlift could therefore do much to probe its underlying mechanics.[6] examinations of the backlift of the bat provide an interesting insight into how skilled batters achieve control of the bat to effectively and efficiently swing their arms to successfully strike a ball. many batters have been observed to adopt a backlift that is diverted away from their body, rather than positioning their bat directly behind them as is commonly advocated in the coaching literature.[5] this is contrary to what may be logically expected as the most effective means of preparing for a straight and efficient downswing.[5,7] it was also found that angling of the backlift away from the body was common, and was similar for all skilled and lesser-skilled batters. it has been proposed that this angle may provide a comfortable position for the batters to place their hands in preparation for the subsequent downswing, allowing for a possible more ‘rotary’ movement of the wrists by which the bat’s backswing and downswing can be performed in a continuous motion.[5] research conducted in australia by stuelcken et al. [7] on international batsmen (n = 9) was one of few studies that demonstrated findings of the backlift in cricket batting. the study showed that path tracings of the bat indicated a distinctive loop, which was unexpected.[7] there was no clear evidence provided by the authors to explain the cause of this significant loop, aside from the fact that a greater diversity of strokes would be a possible outcome as batsmen would get used to hitting the ball in this way. in addition, it was found that the path of the bat deviated laterally from the mean alignment of the shoulders, reaching an average maximum angle in the transverse plane of 47° (after the batsmen initiated the backlift). the study then indicated how this angle was reduced by a mean of 23° at the top of the backlift, which showed that the position of the bat was increasingly lateral from an alignment that would enable the required bat plane to drive to the offside.[8] stuelcken et al.[7] also proposed that batsmen manoeuver their bat by using their wrists as levers to position the bat close to the body’s centre of mass. this may help to keep the bat’s centre of mass close to the batter’s base of support, and ultimately allow a later downswing, thereby background: this study aimed primarily to investigate the lateral batting backlift technique (lbbt) among semiprofessional, professional and current international cricket players. a key question was to investigate whether this technique is a factor that contributes to success for cricket players at the highest levels of the game. methods: the participants in this study’s sample (n = 130) were south african semi-professional players (sp) (n = 69), professional players (pp) (n = 49) and south african international professional players (sai) (n = 12). biomechanical and video analyses were performed on all the participating groups. classifiers were utilised to identify the batting backlift technique type (bbtt) employed by all batsmen. all statistics and wagon wheels (scoring areas of the batsmen on a cricket field) were sourced online. a pearson’s chi-squared test, student t-test, one-way analysis of variance and t-test were performed in this study. all analyses were performed using r (r core team) at a significance level of α = 0.05. results: this study found that a lbbt is more common at the highest levels of batsmanship with batsmen at the various levels of cricket having percentages of the lbbt as follows: sp = 37%; pp = 38%; sai = 75%; p = 0.001. there was also a noticeably higher difference in the highest scores and career averages between all groups of players, as well as batsmen who either use a straight batting backlift technique (sbbt) or a lbbt. this study also found that sai batsmen who used the lbbt were more proficient at scoring runs in various areas around the cricket field (according to the wagon wheel analysis). conclusion: this study found that a lbbt is a contributing factor for success regarding players wanting to play cricket at the highest levels. cricket coaches should also pay attention to the direction of the backlift with players, especially when correlating it to various scoring areas on the cricket field. further in-depth research is required to fully investigate the change in batting backlift techniques among cricket players over a long-term period. keywords: video analysis, biomechanics, coaching, optimising performance s afr j sports med 2019;31:1-9. doi: 10.17159/2078-516x/2019/v31i1a5460 http://dx.doi.org/10.17159/2078-516x/2019/v31i1a5460 https://orcid.org/0000-0001-9464-6854 https://orcid.org/0000-0003-3057-231x original research sajsm vol. 31 no. 1 2019 2 helping to overcome the temporal constraints inherent in batting. if the wrists were to be moved away from the body in the bat’s backswing, more energy and time would be required to produce the backswing and downswing respectively.[7,8] if the wrists are kept close to the body, the batter is afforded a mechanical advantage as the moment of inertia required to move the bat at a given velocity is reduced. this decreases the amount of muscular effort required to play a stroke, allowing the bat to travel through a smaller arc to enable its faster movements.[7,8] recently, noorbhai and noakes[8] followed on from the above study which had shown that a vast majority of successful batsmen (77%) in the last century had used a lateral batting backlift technique (lbbt). it was also investigated that the lbbt is a key contributing factor to the success of the overall cricket batting technique.[8] the lbbt is one in which the bat is lifted laterally in the direction of second slip or gully. therefore, the face of the bat is directed towards point or the offside. by contrast, the backlift, where the bat is lifted towards the stumps or first slip and the face of the bat points towards the wicket-keeper or the ground, is known as the straight batting backlift technique (sbbt).[8] expert coaches have frequently supported the notion that there is no necessarily ‘right’ or ‘wrong’ way to bat, and that many of the greatest players have exhibited techniques not necessarily commensurate with those recommended in coaching manuals.[9] for example, sir donald bradman (widely considered as the greatest batter of all time) exhibited a highly unique ‘rotary’ technique, which is contrary to coaching conventions, and is yet to be replicated.[8,9] in modern coaching manuals (those published after 2009), it has become an acceptable norm for batsmen to lift the bat in the direction of the slips. a mixed-methods study conducted among 161 coaches around the world showed that most of them (83%) coach the sbbt technique as opposed to the lbbt at various proficiency levels of the game.[9] with regards to the higher levels of cricket, most coaches understand the potential value of the lbbt but have challenges coaching it. [9] as a previous study by these authors had analysed successful batsmen only at the highest international level [8], this present study attempts to investigate the batting backlift technique (bbt) among semi-professional, professional and current international cricket players. the findings of the previous study suggested that the lbbt is a likely contributing factor to effective batsmanship. therefore, a key question in this present study was to investigate to what extent batters at the lower levels of the game use the lbbt. these authors’ hypothesis suggests that the lbbt acts as a selective factor among proficient batters at the highest levels of cricket. since the backlift direction can be readily detected with qualitative observations from the direction in which the toe of the bat is pointing, and since there are additional gaps to explore regarding the lbbt as highlighted above, these authors considered it feasible to investigate the following question: is a lbbt used more frequently by batters at the highest levels of the game, compared to batters at lower levels? as previously mentioned, the authors hypothesised that the lbbt is a contributing factor for cricket players wanting to play cricket at the highest levels of the game. methods study design this was a cross-sectional research study in which analytical and qualitative biomechanical research methods were employed. ethical considerations ethical approval for the study was granted by the human research ethics committee of the university of cape town (hrec: 586/2014). all participants provided signed consent prior to participating in the study. this study conforms to the world medical association declaration of helsinki on ethical principles for research involving human subjects. participants participants (n = 130) were south african semi-professional players (sp) (n = 69), professional players (pp) (n = 49) (fig. 1) and south african international professional players (sai) (n = 12) who played in the cricket south africa (csa) domestic competitions and international cricket council (icc) fixtures respectively during the 2015/2016 cricket season. the sample group of sp is reflective of nearly 50% of the total population sample of the 13 semi-professional teams with approximately 143 players in south africa, while the pp group (n = 49) is part of the six franchise teams in south africa, which is indicative of 74% of the total sample of approximately 66 players. all players either represented their provincial, franchise or national team(s). study procedure various types of deliveries (n = 6; two short deliveries, two good length deliveries, two full deliveries, either pitched on middle leg or outside off stump) were analysed from the sp and pp when they faced a fast, fast-medium or spin bowler. any deliveries that were determined as wide, no-ball or a full toss were excluded from this analysis. participants were required to bat using their usual batting technique in either a match or practice situation. for the sai group, the deliveries were randomly chosen. similarly, any deliveries that were determined as wide, no-ball or a full toss were also excluded from this analysis. the researchers had considered the use of the bowling machine to ensure standardisation during the study. however, the objective of the study was to mimic a match situation (through practices in the nets or match practices) and an environment where various players had bowled to the batsmen. legitimate deliveries by the bowlers were not permutated, allowing for the measures and responses from the batsmen to be consistent and accurate. all six deliveries per batsman were analysed and the still frame that best represented the player based on how the various deliveries were faced. the batsmen were used in the figure descriptions to determine the backlift type. original research 3 sajsm vol. 31 no. 1 2019 for the sai players, video footage was obtained via youtube (http://www.youtube.com), since it was challenging to recruit the south african international cricket team while they were on tour overseas. biomechanical and video analyses biomechanical and video analyses were performed on all participating groups. these included the measurement of a photo sequence with drawing tools, and a static angle range calculation of the batsman’s technique utilising the kinoveatm (kinovea by joan charmant, version 0.8.15) software package, in conjunction with a virtual protractor to ensure further reliability of the angle ranges. the analyses were done similarly to those in other studies[7,8] whereby the initial movement of the batsman was determined from the first frame before the initiation of the backlift, while initial movement patterns were assessed qualitatively by viewing the footage. the backlift represented the period from the initiation of the backlift to the maximum vertical displacement of the toe of the bat. the video frame was also selected immediately before the bowler released the ball. these frames were then used to determine the type of batting backlift technique for each type of delivery bowled. variables of interest included the direction of the backlift and the direction of the face of the bat during the backlift from a canon legria hf r506 hd camcordertm video camera attached to a laptop computer. an external hard drive from the video camera was inserted into the laptop for further usage of the software. the frontal camera was situated 20 m away from the participants (for the sp and pp only) and in the line of where the bowler released the ball, just behind the bowler facing the batsman (fig. 2). fig. 1. semi-professional and professional cricket players from south africa (n = 118). semi-professional teams include western province, eastern province, border, kwazulu-natal inland, northerns, gauteng, easterns, north west and free state. professional teams include cobras, warriors, dolphins, titans, lions and knights. fig. 2. camera setup for the analysis in the frontal view fig. 3. lines and vectors drawn to depict the angle of the backlift (adapted from: noorbhai et al., 2016[12]). note: both these batsmen are using the lbbt right-hand batsman left-hand batsman original research sajsm vol. 31 no. 1 2019 4 classifiers of the backlift classifiers were utilised to identify the type of batting backlift technique employed by all batsmen. these classifiers were coded respectively as 1 (bat face facing straight back and towards the wicket-keeper or the ground), 2 (bat face facing first or second slip), and 3 (bat face towards gully or point). if the bat is directed fairly straight back or towards the slips/gully regions but has an open face, it is classified as classifier 3. angle ranges were conceptualised to determine these classifiers (1: between 0o – 25o), (2: between 25o – 45o), (3: between 45o – 80o). for the purpose of this study, the toe of the bat is defined as the vector orthogonal to the toe being the pointer.[10] this strengthens the validity and reliability of the analysis as the backlift can be readily detected and analysed at different positions and time points in the backlift.[11] drawing a vector is a common approach in defining the toe of the bat and how it will point in a particular direction.[2] lines and vectors were drawn (1) vertically from the head to the hands (green line), (2) a line drawn horizontally to show where the hands rest (blue line), and (3) a line drawn obliquely to show the direction of the bat during the backlift (red line) (fig. 3). the lines that were used on the batsmen were done on an individual basis as each batsman’s hands (where they rest) and the vertical line are different. the horizontal line is the starting point of where the batsman’s hands rest. as such, if the vertical line meets at one batsman’s left eye or the other batsman’s right eye, it is of no consequence, as in each case the player’s head rests in different proportions to where their hands rest. the oblique line started from the top of the bat towards the toe of the bat which depicted the angle range. the still photo of the batsman was analysed while the ball had just been released from the bowler. these lines create an angle range to show how far away the bat is from the body in the frontal plane and how much rotation is performed before the bat makes contact with the ball. the researcher accounted for perspective error by limiting the type of videos observed, as well as including horizontal lines in the background in a separate document for analysis. search strategy and sources for players’ career statistics and wagon wheels cricinfo (http://www.espncricinfo.com) was used to retrieve the career statistics of each player (matches played, highest score, career runs scored, averages and strike rates). south african domestic players’ statistics were also sourced from their first-class (threeor four-day games) and list a (one-day games) results. in addition, wagon wheels of the sai were also sourced via cricinfo to determine the areas on the cricket field where the batsmen were scoring their runs and to correlate those areas with their batting backlift technique. wagon wheels and video footage of the sai were obtained from a player’s highest score in a test or odi match. wagon wheels of the sp and pp were not available. however, the picture frames from the video footage of the sp (western province, eastern province, border, kwazulu-natal inland, northerns, gauteng, easterns, north west and free state) and pp (cobras, warriors, dolphins, titans, lions and knights) were used to analyse the batting backlift technique of the players. quantitative data analysis a pearson’s chi-squared test was performed to determine whether percentages of batsmen using a lbbt differed between the levels of professional cricket. the student’s t-test was used to compare highest scores, career averages and strike rates between batsmen with a lbbt and sbbt, and batsmen in each population group (sp, pp and sai), respectively. for sai, just t-tests could be performed for test matches as only a single batsman using a sbbt had scored in odi matches and the means for this group could be calculated. a one-way analysis of variance (anova) was also calculated for highest scores, career averages and strike rates for first-class cricketers and list a statistics. all analyses were performed using r[13] at a significance level of α = 0.05. results in this study, 37% of sp and 38% of pp used a lbbt respectively (p>0.05) (tables 1 and 2). among the sp, 44% of players were classifier 1, 17% were classifier 2 and 37% were classifier 3 (lbbt). among the pp, 34% of players were classifier 1, 26% were classifier 2 and 38% were classifier 3 (lbbt). there were also 75% of sai (table 3 and 4) who used the lbbt. in this study, the majority (75%) of sai batsmen (playing at international level) used a lbbt, while only between 37% – 38% of batsmen on the other levels used the lbbt (table 5 and fig. 4). the percentage of cricketers using the lbbt is significantly different to those using the sbbt across the different levels (χ2 = 39.02, df =3, p = 0.001). highest scores the analysis was significant for both first class cricket, f (2, 114) = 19.369, p = .000 and list a cricket, f (2, 11) = 18.85, p = .000 (table 6). comparisons indicated that the high scores of cricketers at the amateur level was significantly different from the franchise level for both first-class cricket, t(103) = -3.18, p = .000 and list a cricket, t(102) = -3.61, p = .000. the high scores of cricketers at the amateur level was significantly different from the international level for both first class, t(64) = -6.32, p = .000 and list a cricket, t(27) = -8.21, p = .000. similarly, high scores of cricketers at the franchise level was significantly different from the international level for both first class cricket, t(61) = 3.87, p = .000 and list a cricket, t(28) = -4.88, p = .000 (table 6). when comparing cricketers in the pp group who either had a sbbt or a lbbt, the analysis was significant for highest scores in list a cricket (t = -2.02; p = 0.02) (table 7). career averages the analysis was significant for both first-class cricket f(2, 114) = 10.89, p = .000 and list a cricket, f(2, 11) = 14.31, p = .000 (table 6). comparisons indicated that the averages of cricketers at the amateur level were significantly different from the franchise level for both first-class cricket, t(103) = 1.78, p = .038 and list a cricket, t(103) = 2.64, p = .005. the averages of cricketers at the amateur level were significantly different from original research 5 sajsm vol. 31 no. 1 2019 the international level for both first-class cricket, t(36) = 7.75, p = .000 and list a cricket, t(31) = -7.75, p = .000. similarly, career averages of cricketers at the franchise level were significantly different from the international level for both first-class cricket, t(46) = -5.93, p = .000 and list a cricket, t(31) = -5.22, p = .000 (table 6). when comparing cricketers in the sp group who either had a sbbt or a lbbt, the analysis was significant for career averages in first-class cricket (t = -2.19; p = 0.02) (table 7). when comparing cricketers in the sp group (with a sbbt) to the pp group (with a lbbt), the analysis was significant for first-class cricket among highest scores (t = -3.01; p = 0.002) and career averages (t = -3.13; p = 0.001), and for list a cricket among highest scores (t = -3.94; p = 0.001) and career averages (t = -3.13; p = 0.001) (table 7). strike rates as expected, there were no significant differences for all analyses on strike rates. table 1. a summary of the bbt characteristics at semi-professional level (sp) (n = 69) amateur team n lateral bbt straight bbt classifier 1 classifier 2 classifier 3 free state 3 1 2 2 0 1 north west 4 2 2 2 0 2 gauteng 10 4 6 3 3 4 easterns 10 3 7 5 2 3 northerns 8 3 5 3 2 3 kwazulu-natal inland 7 3 4 3 1 3 border 7 3 4 3 1 3 eastern province 10 5 5 3 2 5 western province 10 2 8 7 1 2 total (%) 69 26 (37.7) 43 (62.3) 31 (44.9) 12 (17.4) 26 (37.7) bbt, batting backlift technique; n, sample number table 2. a summary of the bbt characteristics at professional level (pp) (n = 49) franchise team n lateral bbt straight bbt classifier 1 classifier 2 classifier 3 knights 8 4 4 2 2 4 lions 5 1 4 3 1 1 titans 8 4 4 2 2 4 dolphins 10 5 5 3 2 5 warriors 10 3 7 4 3 3 cobras 8 2 6 3 3 2 total (%) 49 19 (38.8) 30 (61.2) 17 (34.7) 13 (26.5) 19 (38.8) bbt, batting backlift technique; n, sample number table 3. characteristics and performances of the south african national team up to and including the 2015/2016 season at test and odi levels. player runs tests runs odi test odi classifier bbt high score average strike rate high score average strike rate ab de villiers 8074 8621 278 50.5 53.7 162* 54. 6 100.2 3 lateral hashim amla 7358 6204 311* 51.5 50.1 159 52.1 89.1 3 lateral quinton de kock 407 2319 129* 45.2 66.2 138* 42.9 91.7 3 lateral dean elgar 1249 98 121 36.7 45.2 42 24.5 61.3 1 straight faf du plessis 1682 2944 137 41.0 39.7 133* 39.8 85.7 3 lateral jp duminy 1423 4028 166 32.3 42.8 150* 38.7 83.3 3 lateral temba bavuma 383 102 38.3 47.2 1 straight stephen cook 140 115 70.0 48.8 3 lateral rilee rossouw 860 132 33.1 94.6 3 lateral david miller 1819 138* 35.0 100.0 3 lateral farhaan behardien 767 70 30.7 97.3 3 lateral stiaan van zyl 355 101* 27.3 54.0 2 straight bbt, batting backlift technique; odi, one day internationals. * indicates not out; – indicates player did not play tests/odi format. player’s highest score is in bold text. these stats were accessed during june 2016. original research sajsm vol. 31 no. 1 2019 6 for test matches, the average highest score for south african international batsmen using a lbbt was significantly higher than that for batsmen using a sbbt (t = 2.34, p = 0.03) (table 8). however, the use of a lbbt or a sbbt had no significant effect on total career runs (t = 1.70, p = 0.079), average run rate (t = 1.81, p = 0.056) and strike rate (t = 0.24, p = 0.41). discussion the main finding of this study has shown that a lbbt is table 4. performances of the south african national team batsmen up to and including the 2015/2016 season at first-class and list a levels player runs firstclass total runs list a total first-class list a classifier bbt high score average strike rate high score average strike rate ab de villiers 9961 10721 278* 49.8 55.5 162* 54.1 3 lateral hashim amla 15477 8562 311* 49.7 159 45.3 3 lateral quinton de kock 3225 4555 194 48.8 79.9 178 41.0 95.9 3 lateral dean elgar 9858 4223 268 43.8 49.3 117 39.4 77.1 1 straight faf du plessis 6763 7858 176 40.2 185 45.1 88.9 3 lateral jp duminy 6699 6228 260* 47.1 49.9 150* 37.7 81.6 3 lateral temba bavuma 5554 1607 162 37.7 50.6 113 29.2 80.9 1 straight stephen cook 12983 5182 390 40.5 127* 38.9 78.3 3 lateral rilee rossouw 5940 4668 319 44.3 63.6 137 38.5 93.5 3 lateral david miller 2851 4595 177 35.6 56.8 138* 40.3 101.7 3 lateral farhaan behardien 5403 4070 150* 39.7 54.0 113* 37.3 94.4 3 lateral stiaan van zyl 8401 3131 172 42.8 51.5 114* 35.9 73.7 1 straight bbt, batting backlift technique; odi, one day internationals. * indicates not out; – indicates player did not play tests/odi format. these stats were accessed during march 2017. table 5. percentage of players across different professional levels applying the lbbt or sbbt, assigned to classifiers 1 3 level n backlift batting technique (%) classifier (%) lbbt sbbt 1 2 3 semi-professional (sp) 69 38 62 45 17 38 professional (pp) 49 39 61 35 26 39 south african international (sai) 12 75 25 17 8 75 total 155 51 49 32 17 51 lbbt, lateral batting backlift technique; sbbt, straight batting backlift technique; n, sample number table 6. first-class and list a performances for sp, pp and sai groups level n first-class list a high score average strike rate high score average strike rate semi-professional (sp) 69 110 27.0 51.5 56 22.4 74.6 professional (pp) 49 146 30.4 50.5 91 28.0 77.4 south african international (sai) 12 232 42.1 45.5 146 38.3 86.6 n, sample number. high score refers to overall average highest score made by all the players in the particular match format. average refers to the overall average runs scored by all of the players in the particular match format. strike rate refers to the overall strike rate achieved by all of the players in the particular match format. table 7. first-class and list a performances for sp and pp groups separated into a sbbt or a lbbt level n first-class list a high score average strike rate high score average strike rate amateur sbbt 62 111 24.7 51.6 52 20,8 75.4 amateur lbbt 38 107 29.7 51.3 62 24,3 73.6 franchise sbbt 61 138 28.7 48.9 84 27,1 75.3 franchise lbbt 39 164 33.3 53.2 104 29,4 80.8 sp, semi-professional; pp, professional; lbbt, lateral batting backlift technique; sbbt, straight batting backlift technique; n, sample number. high score refers to overall average highest score made by all the players in the particular match format. average refers to the overall average runs scored by all of the players in the particular match format. strike rate refers to the overall strike rate achieved by all of the players in the particular match format. original research 7 sajsm vol. 31 no. 1 2019 commonly used by batsmen at the highest levels of cricket. despite the small differences in percentages of sp and pp using the lbbt, this finding is nevertheless compatible with the interpretation in this study that the lbbt is more common at the highest levels of cricket (fig. 4). career averages and highest scores there were also noticeably higher differences in the highest scores and career averages between all groups of players, as well as batsmen who either use a sbbt or a lbbt. as such, the lbbt acts as a selective factor among proficient batters at the highest levels of cricket batting. this study has shown that the analysis of high scores and career averages was significant for both first-class cricket and list a cricket. comparisons indicated that the high scores and career averages of cricketers at the amateur level were significantly different from the franchise level for first-class cricket and list a cricket. the high scores and career averages of cricketers at the amateur level were significantly different from the international level for both first-class and list a cricket. similarly, high scores and career averages of cricketers at the franchise level were significantly different from the international level for first-class cricket and list a cricket. this shows how performances (in the form of career averages and highest scores) increases with players who use the lbbt at the higher levels of the game in both limited overs and four-day cricket. wagon wheels were only available for the sai groups, and therefore scoring areas and career statistics of these players will be clarified. scoring areas the sai batsmen’s wagon wheels show interesting findings. batsmen with a lbbt were found to score runs in more areas around the cricket field and in front of the wicket. by contrast, batsmen with a sbbt scored runs in selected areas around the cricket field only and roughly in front of the wicket (mostly behind square with shots such as the late cut and leg glance). although the late cut to third man and leg glance to fine leg can be rewarding for batsmen, these are not shots that are always commonly played by batsmen within an innings. some batsmen who are more defensive in their approach would score runs in selected areas around the cricket field whereas more aggressive batsmen may score runs in various parts of the cricket field. interestingly, wagon wheel examples of three left-handed sai batsmen with a lbbt (quinton de kock, rilee rossouw and david miller) (supplementary figure 5) show that most of their runs are scored in front of the wicket and not behind square. all of their productive shots were on the on-side (the pull and on-drive). it is important to note that although there are multiple factors associated with scoring areas of batsmen (such as bowler’s lines and lengths, the grip of the batsman and formats of the game), backlift types of a batsman is not a single causative factor but rather one of the likely contributing factors among the many factors that contribute towards successful batting. in addition to the sai batsmen’s scoring areas, it is also worth noting their productive shots used during their highest scoring innings in either a test match or odi. batsmen with a lbbt (n = 9) had a leg glance and pull as their most productive shot (the leg-side), whereas batsmen with a sbbt (n = 3) had a cover drive as their most productive shot (off-side). from this, it is suggested that batsmen with a lbbt are more likely to go at a ball harder in the high scoring zone (on the leg-side) as opposed to a less high scoring zone (on the off-side). in this instance, batsmen who had a lbbt mostly used the leg glance and pull (leg-side), implying that these are not straight bat shots whereas batsmen with a sbbt mostly played a cover drive, implying a straight bat shot. it is also important to consider the varied formats of the game. table 8. mean performance per cricketer using lateral (lbbt) or straight (sbbt) backlift batting techniques at south african international (sai) level bbt n test odi total runs average runs strike rate high score total runs average runs strike rate high score lbbt 9 3181 ± 1189 48.4 ± 4.2 50.2 ± 3.1 174 ± 24 3445 ± 915 40.9 ± 2.8 92.7 ± 2.1 120 ± 15 sbbt 3 662 ± 293 34.1 ± 3.4 48.8 ± 2.6 112 ± 8 98 ± 0.0 24.5 ± 0 61.3 ± 0 42 ± 0.0 total 12 2341 ± 895 43.6 ± 3.6 49.7 ± 2.2 153 ± 19 3073 ± 808 39.0 ± 2.8 89.2 ± 3.4 101 ± 16 data expressed as mean ± standard error bbt, batting backlift technique; lbbt, lateral batting backlift technique; sbbt, straight batting backlift technique; n, sample number; odi, one day internationals fig. 4. the percentage of batsmen using the lbbt among sp, pp and sai cricketers (n = 155). pp, professional players; sp, semi-professional players; sai, south african internationals original research sajsm vol. 31 no. 1 2019 8 batsmen would be more aggressive in one-day games as opposed to test matches. further research is required in this area if there are variances in the batting backlift techniques of the same batsmen in all three formats of the game (tests, odis and twenty20). career statistics apart from farhaan behardien, three sai batsmen with a sbbt were found to have the lowest high scores. although an individual high score may not be an indicator for success, the observed pattern does support the idea that batsmen with a lbbt might be able to score runs more rapidly than batsmen with a sbbt. furthermore, these three batsmen are part of the five batsmen from the sai cohort that have the lowest strike rate in either tests or odis. although the strike rate statistic is more pertinent in the odi format of the game, it still raises the question of whether batsmen with a lbbt are able to score runs more rapidly than batsmen with a sbbt. the link between the lbbt and potential long-term success in cricket batting the use of the lbbt may have decreased among a number of players as a result of exposure to traditional coaching methods and philosophies earlier in their careers.[12] it has also been shown that coaching with the sbbt may be detrimental to cricketers’ future prospects[12], as this study has shown that the lbbt produces better performances at the higher levels. in addition, if such players are not coached traditionally, they automatically hit the ball using the lbbt. strengths and limitations the strengths of this study are as follows:  the ability to retrieve both completed batting records and video footage of all batsmen in this study.  the sample number of 130 batsmen (sp: n = 69; pp: n = 49 and sai: n = 12) is reflective of over half of the population sample of semi-professional and professional cricketers in south africa.  the analysis of all the six south african franchise teams (n = 49 batsmen) and nine out of the 13 south african semi-professional teams (n = 69).  each group of participants played in the same environment and in the same month, which limited a seasonal effect.  biomechanical and video analyses of players was also obtained objectively and was not self-reported. with regards to the limitations:  only wagon wheels of the sai could be sourced. however, this sample was sufficient to correlate the runs scored on the field with the players’ bbt.  the dots per inch (dpi) quality for some of the videos with the sp and pp appeared to be inconsistent due to the variances in weather when testing, as well as varied camera distances behind the bowler.  the researchers accounted for perspective error by limiting the type of videos observed and including horizontal lines in the background.  exact angles were not measured, while it was only possible to measure and report on angle ranges. this was because the analysis was conducted in a field setting (due to the number of players studied) and not in a laboratory. coaching implications all batsmen are unique in their technique and approach and will display attributes that are distinctive and suit them best as individual players. as scientists and coaches, the above should be taken into consideration in order to assist players with subtle discrepancies that may hinder their performance. innovative coaching tools (specifically for the backlift), in the form of a coaching cricket bat and a mobile application, are also available for coaches and players to improve and assist with the coaching of the lbbt.[14,15] a lbbt may not come naturally to some professional players. coaches should also pay attention to the direction of the backlift with players, especially when correlating the backlift to various scoring areas on the cricket field. at semi-professional and professional levels, a coach can only do so much to ensure optimal performance and subtle technical optimisations. conclusion this study found that a lbbt is more common at the highest levels of cricket batsmanship. batsmen at the various levels of cricket had percentages of the lbbt as follows: sp = 37%; pp = 38%; sai = 75%; p = 0.001. the lbbt is a contributing factor for cricket players wanting to play cricket at the highest levels of the game. this study showed that there was also noticeable difference in the highest scores and career averages between all groups of players in general as well as batsmen who either use a sbbt or a lbbt. cricket coaches need to pay attention to the direction of the backlift with players, especially when correlating the backlift to various scoring areas on the cricket field. further in-depth research is required to fully investigate the change in batting backlift techniques among cricket players over a long-term period. author contributions: m h noorbhai: designed the study, performed the data collection and analysis of the participants and wrote the manuscript. t d noakes: conceptualised the research project, assisted in the design of the study, and assisted in the write-up of the manuscript. references 1. davis k. discovering biomechanical principles of batting in cricket. in: matsui h, kobayashi k, eds. biomechanics viii-b: proceedings of the eighth international congress of biomechanics. champaign, ill.: human kinetics 1983:915-922 2. kreighbaum e, barthels km. biomechanics: a qualitative approach for studying human movement. 4th ed. boston: allyn and bacon 1996:168-192 3. mullineaux dr, bartlett rm, bennett s. research design and statistics in biomechanics and motor control. j sports sci 2001;19(10):739-760. [doi: 10.1080/026404101317015410] 4. stretch ra, bartlett rm, davids k. a review of batting in men’s cricket. j sports sci 2000;18(12):931-949. [doi:10.1080/026404100446748] original research 9 sajsm vol. 31 no. 1 2019 5. sarpeshkar v, mann dl. biomechanics and visual-motor control: how it has, is, and will be used to reveal the secrets of hitting a cricket ball. sports biom 2011;10(4):306-323. [doi: 10.1080/14763141.2011.629207] 6. noorbhai mh, noakes td. advances in cricket in the 21st century: sciences, performance and technology. afr j phys health educ recreat dance 2015;21(4:2):1310-1320. [https://hdl.handle.net/10520/ejc182298] 7. stuelcken mc, portus mr, mason br. off-side front foot drives in men’s high performance cricket. sports biomech 2005;4(1):17-35. [doi: 10.1080/14763140508522849] 8. noorbhai mh, noakes td. a descriptive analysis of batting backlift techniques in cricket: does the practice of elite cricketers follow the theory? j sports sci 2016;34(20):19301940. [doi: 10.1080/02640414.2016.1142110] 9. noorbhai mh, noakes td. an evaluation of the coaching methods of the batting backlift technique in cricket. journal of qualitative research in sports studies 2018; 12(1):35-56. 10. glazier ps, davids k, bartlett rm. dynamical systems theory: a relevant framework for performance-orientated sports biomechanics research.. sportscience 2003;7 [https://www.sportsci.org/jour/03/psg.htm] accessed 12 january 2019. 11. hopkins wg. measures of reliability in sports medicine and science. sports med 2000;30(1):1-15. [doi: 10.2165/00007256200030010-00001] 12. noorbhai mh, noakes td. an analysis of batting backlift techniques among coached and un-coached cricket batsmen. s afr j res sport ph 2016;38(3):143-161. [https://hdl.handle.net/10520/ejc199886] 13. r core team. r: a language and environment for statistical computing. r foundation for statistical computing, vienna, austria, 2014. [http://www.r-project.org] accessed 12 january 2019. 14. noorbhai mh, woolmer rc, noakes td. novel coaching cricket bat: can it be used to enhance the backlift and performance of junior cricket batsmen? bmj open sport exerc med 2016;2(1):e000141. [doi:10.1136/bmjsem-2016-000141] 15. noorbhai mh, chhaya mma, noakes td. the use of a smartphone based mobile application for analysing the batting backlift in cricket. cogent medicine 2016;3:1214338. [doi: 10.1080/2331205x.2016.1214338] case report 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license a tale of two sit-bones: the cyclist’s ischial hygroma (perineal nodular induration) j swart,1 mbchb, mphil (sem), phd; r v p de villiers,2 mbchb, m. med rad. d; f roux,3 mbchb, fc rad (diag), da(sa); f rademan,4 mbchb, mmed (surgery), gks (surgery); g thom,5 mbchb, mmed (anaes), fca (sa) 1 division of exercise science & sports medicine. department of human biology, university of cape town, south africa 2 sports science radiology, winelands radiology, sports science institute of south africa. boundary rd, newlands, south africa 3 tygerberg academic hospital, cape town, south africa 4 suite 4, mediclinic durbanville, 9 paul kruger road, durbanville, cape town, south africa 5 private practice, claremont, cape town, south africa corresponding author: j swart (jeroen.swart@uct.ac.za) the biker's nodule or ischial hygroma is a relatively unique pathology that most commonly affects competitive male cyclists and to a lesser extent, females. there are also records of this condition occurring in female equestrians [1], as well as one interesting but unusual case of it occurring in a lawnmower tester. [2] these lesions are known by several other terms, including a third or supernumerary testicle, accessory testicle, perineal hygroma or induration. [1,3,4] perineal nodular induration was first described by vuong et al. in 1988 who described two cyclists with this condition. [3] as previously mentioned, a typical biker's nodule occurs mainly in male competitive cyclists. symptoms include pain on pressure, such as when sitting in the saddle. a dull constant ache even when not riding has also been described. [1] in one of this study’s cases, the patient also had symptoms due to the close proximity to the sciatic nerve. typically, a nodule is palpable on one or both sides of the midline, posterior to the scrotal sac, usually 2-3 cm in size. [2, 4, 5] this nodule is typically fibroelastic and may adhere to the adjacent connective tissue. [6] in females, the nodules are usually unilateral and may occur in the typical location as described above or may occur in either or both of the labium majora.[7] the lesion is believed to be caused by increased friction and vibration between the ischial tuberosities and the hard saddle as a result of the constant rubbing of the superficial perineal fascia against bony structures.[2,7,8] thus mountain bikers are regarded as a particularly high-risk group for developing these lesions. [9] the variant which occurs in the labia majorus may show an admixture of adipose tissue, variably cellular hyalinised tissue containing bland, spindle-shaped fibroblasts, blood vessels, and nerve fibres. in some areas, thick cords of fibrous tissue imparting a keloid-like appearance can occur. other histologic features include plump mesenchymal cells with round or ovoid nuclei and abundant eosinophilic cytoplasm resulting in an epithelioid, plasmacytoid, or ganglion-like appearance, lymphocytic infiltrate around blood vessels, foci of fat necrosis, and collections of elastic fibres [7]. two typical cases of perineal nodular infiltration are described which are managed with differing modalities. case report 1 history a 45-year-old competitive female cyclist presented to her sports physician with a year-long history of a dull ache in the left inner buttock which radiated to the left hamstring. the pain was aggravated by cycling and sitting on her chair at work. she had initially been treated unsuccessfully by a physiotherapist for hamstring tendinosis. examination no visible abnormality was detected. on palpation, a nodule of approximately 2 x 2 cm was noted adjacent to the left ischial tuberosity. it was mildly tender on palpation and not fixed to the underlying muscle or bone. special investigations the patient was initially sent for diagnostic high-resolution ultrasound. this was followed by a mri study of the pelvis. high-resolution greyscale ultrasound demonstrated a well the ischial hygroma, also known as a perineal nodular induration, is a relatively rare and mostly cycling-specific injury that is often incorrectly diagnosed and managed. here two cases with divergent managements are described to highlight the spectrum of treatment available to manage this condition. the presentation, assessment and management of two cases of perineal nodular induration are discussed. the management options, namely surgical excision vs conservative management, with saddle pressure mapping highlight that there is no single optimal method and that a multidisciplinary approach should be applied to treat these injuries successfully. perineal nodular induration should be investigated appropriately to exclude less benign causes of perineal masses. conservative management and surgical excision can both be successful. clinicians should be familiar with the assessment and management of this relatively rare but debilitating condition in competitive cyclists. keywords: cycling, perineal injury s afr j sports med 2019; 31:1-4. doi: 10.17159/2078-516x/2019/v31i1a5641 https://orcid.org/0000-0001-7098-0313 http://dx.doi.org/10.17159/2078-516x/2019/v31i1a5641 case report sajsm vol. 31 no. 1 2019 2 circumscribed predominantly hypo-echoic 2 x 1 cm nodule in the subcutaneous tissue just medial to the ischial tuberosity (fig. 1). magnetic resonance imaging showed a fairly wellcircumscribed 20 mm x 15 mm mass in the subcutaneous tissues of the left buttock in close relation to the ischial tuberosity and proximal insertion of the hamstring. the lesion was hypointense on all sequences (fig. 2). based on these and clinical findings the diagnosis of an ischial hygroma was made. management the sports physician injected a combination of local anaesthetic and corticosteroid into the nodule. there was no subsequent improvement. she was then referred for surgical excision of the lesion. dissection through the skin and subcutaneous tissue revealed a fibrotic mass approximately 3 cm in size situated medial to the sciatic nerve and superficial to the hamstring origin at the ischial tuberosity. a white focus was noted centrally within the lesion compatible with the injected corticosteroid. histology revealed a combination of dense hyalinised fibrous tissue, surrounding oedematous fibrous tissue and pseudocystic area compatible with a cyclist nodule (fig. 3). the patient initially had an uneventful recovery and was asymptomatic. however, at a two year follow-up she had not returned to competitive cycling due to persistent discomfort, albeit less than at the time of presentation. case report 2 history a 61-year-old competitive male cyclist presented to these authors’ clinic with a history of insidious onset pain in the left perineal area which occurred during cycling. shortly prior to seeking medical attention, he noted a tender mass in his perineum. examination no visible abnormality was detected. on palpation, a nodule of approximately 1 cm in transverse and 4 cm in longitude was noted adjacent to the left ischial tuberosity. it was firm and rubbery in consistency, mildly tender on palpation, and not fixed to the underlying muscle or bone. special investigations the patient was referred for diagnostic highresolution ultrasound. high-resolution greyscale ultrasound demonstrated a well-defined, heterogeneous, predominately cystic mass inferior to the left scrotum. it measured 5.0 x 2.4 x 4.0 cm and contained hypoechogenic material within it, with no increased vascularity. based on the imaging and clinical findings, it was diagnosed as an ischial hygroma. management the patient was reluctant to undergo surgery and specifically requested conservative management. a comprehensive assessment of his cycling biomechanics and saddle contact point was performed. pre-fitting and static kinematics were performed using ergofittm (http://www.sciencetosport.com/ergofit) software and kinematic tools. saddle pressure mapping was performed using gebiomized® dynamic saddle pressure mapping systems (http://www.gebiomized.de). fig. 1. longitudinal high-resolution greyscale ultrasound image of the perineal region just medial to the ischial tuberosity fig. 2. mri pelvis axial t1 weighted image of the perineal region, demonstrating a low signal intensity lesion to the left of the midline in the superficial soft tissue of the perineum http://www.sciencetosport.com/ergofit case report 3 sajsm vol. 31 no. 1 2019 salient findings were that underwear was being worn under the cycling-specific garment and that the cycling-specific garments were of relatively low quality, with chronic wear demonstrated on the padding material. the kinematic assessment demonstrated excessive saddle height (static knee flexion angle (kfa) of 22° using the holmes10 method) and excessive saddle setback (10.5 cm). this was confirmed on initial saddle pressure mapping by a front: rear pressure balance ratio of 62:38. after correction of the kinematics (kfa of 31° and saddle setback of 6.8 cm) a series of minor adjustments were made and numerous different saddle types were tested to achieve the most favourable saddle pressure mapping possible (pre and post-pressure mapping are shown in fig.4). preand post-changes (table 1) improved overall pressure distribution by:  improving front: rear pressure balance ratio from 62:38 to 46:54  increasing loaded area in left ischial area from 4300 mm2 to 5325 mm2  reducing peak pressure from 923 mbar to 724 mbar the patient returned to cycling activity and has subsequently not experienced any recurrence of symptoms at two-year follow-up. discussion these two cases illustrate several important points. firstly, the nodule may not be initially readily apparent and the symptoms in case 1 were originally thought to be related to the tendinous insertion of the hamstring and sciatic nerve, which lie in close proximity. it is therefore important for clinicians to be aware of this unique entity and to have a high index of suspicion which can improve early management and prevent unnecessary medical treatment, months of frustration and potential loss of income. imaging characteristics are rarely reported; however, an example can be found in a 2009 article by van de perre et al.[4] ultrasound demonstrates a fairly well-circumscribed hypoechoic nodule with an absence of the doppler signal. small internal cystic areas may also be seen. ct (computed tomography) and mri (magnetic resonance imaging) show lack of contrast uptake, which explains the hypovascular nature as seen on histology examinations.[4,7] on an mri, the lesion would be hypointense on all sequences. the primary role of imaging is to determine the location and exact extent of the lesion and to exclude rarer and other important conditions, such as aggressive angiomyxoma.[6] in most clinical scenarios, ultrasound would suffice. [4] if the diagnosis is unclear, imaging plays an important role table 1. saddle pressure mapping values pre-/post-optimisation parameters (pre/ post) pubic bone left ischium right ischium max. pressure [mbar] 1702 / 943 923 / 741 1377 /1023 mean pressure [mbar] 400 / 267 210 / 313 281 / 304 loaded area [mm2] 6400 / 6200 4300 / 5325 4475 / 5775 pressure front / rear 62:38 / 46:54 pressure left / right 43:57 / 51:49 fig. 3. histological characteristics of perineal nodular induration demonstrating dense hyaline tissue and pseudocystic changes fig. 4. preand post-intervention saddle pressure mapping demonstrating increased contact area, reduced peak pressures and more favourable pressure distribution case report sajsm vol. 31 no. 1 2019 4 in the differentiation from other causes of perineal swelling. these would include an abscess, epidermal cyst, cutaneous adnexal mass, lipoma or tumour (sarcoma or metastases).[2, 4, 8] non-mass enhancement on mri is a reassuring feature and readily excludes malignancy.[4] vuong et al. states that this pseudoneoplastic lesion has a relatively constant appearance, but if not realised to be a benign nonneoplastic lesion, there is a potential for misdiagnosis. [3] this again stresses the importance of suspecting this lesion in the correct clinical context and using imaging as an important diagnostic tool. secondly, the management of this entity can be successful by using both conservative and more invasive methods. in these authors’ experience, most clinicians limit management to avoidance of the causative factor, be it cycling or horse riding. this is sometimes not a practical option and, in these authors’ limited experience, it is generally not sufficient as therapy. [4] correct bike setup, saddle type and saddle position will go a long way in relieving symptoms and preventing recurrence of the lesions. special attention should also be given to cycling shorts and the construction of the padding.[4] local infiltration with corticosteroids or hyaluronidase are described as first-line invasive treatment. if none of these therapies are efficacious, surgery should be considered. [3-5, 8] conservative management includes a period of rest from cycling to allow the area to settle which should reduce the size of the lesion but not eliminate it. once the lesion has settled a comprehensive assessment of kinematics and saddle contact point can reduce loading of the area and prevent recurrent episodes of pain and enlargement. however, this requires dedicated expertise in the field of cycling biomechanics and specialised equipment to assess the saddle/cyclist interface. clinicians should enquire about such expertise in their area and refer to the appropriate experts for management. in these authors’ experience, an injection of the lesion with corticosteroids has not resulted in lasting relief but can provide a temporary treatment option or adjunct to more specific management of the kinematics and contact area analysis. clinicians should be aware of the risk of fat necrosis at the injection site which may cause further discomfort on the commencement of cycling. failure to resolve symptoms using conservative measures or a lack of expertise in this field in the clinician’s geographical area should warrant a referral for surgical excision. surgical excision of large hygromas can be technically challenging due to the poorly defined boundary of the lesion and adherence to surrounding structures. as such, the patient may often experience a residual nodule, albeit smaller in size, and experience some persistent discomfort in the area postsurgery. the histopathological features show a myxoid degeneration of the fatty tissue, often with a pseudocyst formation. this is surrounded by dense hyalinised fibrous tissue which merges towards the periphery with oedematous fibrous tissue containing fibroblast-like spindle cells, thick collagen bundles, degenerate elastic fibres, and clusters of capillaries which may show diapedesis of erythrocytes or even haemorrhagic foci. [2,4] however, the lesion is not well vascularised. [4] the margins of the lesion are not well circumscribed and there is no synovial lining. [2,6,11] focally, spindle cells showed mild degenerative atypia reminiscent of that seen in ischaemic fasciitis. in summary, clinicians should have a high index of suspicion for perineal nodular induration in cyclists presenting with perineal pain or pain in adjacent areas. they should be aware of the potential for more serious pathology and use imaging to differentiate these less benign lesions. lastly, management principles can be dictated by the availability of expertise in cycling kinematics in their area but multiple management approaches can result in successful outcomes for the patient. author contributions: j swart: collected data for case 2. analysis. writing rp de villiers: collected data for case 1 and 2. analysis. writing f. rademan: collected data for case 1. analysis. writing f. roux: collected data for case 1. analysis. writing g thom: collected data for case 1. analysis. writing references 1. devers kg, heckman sr, muller c, et al. perineal nodular induration: a trauma-induced mass in a female equestrian. int j gynecol pathol 2010;29(4):398-401. [doi: 10.1097/pgp.0b013e3181ce1341] 2. de saint aubain somerhausen n, geurde b, couvreur y. perineal nodular induration: the 'third testicle of the cyclist', an under-recognized pseudotumour. histopathology 2003;42(6):615-616. [doi: 10.1046/j.1365-2559.2003.01592.x] 3. vuong pn, camuzard p, schoonaert mf. perineal nodular indurations ("accessory testicles") in cyclists. fine needle aspiration cytologic and pathologic findings in two cases. acta cytol 1988;32(1):86-90.[pmid: 3336958] 4. van de perre s, vanhoenacker fm, vanstraelen l, et al. perineal nodular swelling in a recreational cyclist: diagnosis and discussion. skeletal radiol 2009;38(9):919-920, 933-934. [doi: 10.1007/s00256-009-0731-9] 5. asselbergs cp, loeff jw, de jongh gj, et al. [perineal nodular induration]. ned tijdschr geneeskd 2009;153:a58. [pmid: 19818180] 6. gonzalez-perez r, carneroa l, arbide n, et al. [perineal nodular induration in cyclists]. actas dermosifiliogr 2009;100(10):919-920. [doi: 10.1016/s1578-2190(09)70571-2] 7. mccluggage wg, smith jh. reactive fibroblastic and myofibroblastic proliferation of the vulva (cyclist's nodule): a hitherto poorly described vulval lesion occurring in cyclists. am j surg pathol 2011;35(1):110-114. [doi:10.1097/pas.0b013e3181ffd8ab] 8. kӧhler p, utermann s, kahle b, et al. ["biker's nodule"--perineal nodular induration of the cyclist]. hautarzt 2000;51(10):763-765. [pmdi: 11153363] 9. frauscher f, klauser a, hobisch a, et al. subclinical microtraumatisation of the scrotal contents in extreme mountain biking. lancet 2000;356(9239):1414. [doi: 10.1016/s0140-6736(00)02852-x] 11. holmes jc, pruitt al, whalen nj. lower extremity overuse in bicycling. clin sports med 1994;13(1):187-205. [pmid: 8111852] 10. khedaoui r, martin-fragueiro lm, tardio jc. perineal nodular induration ("biker's nodule"): report of two cases with fineneedle aspiration cytology and immunohistochemical study. int j surg pathol 2014;22(1):71-75. [doi: 10.1177/1066896912465008] case report 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license testosterone boosters: a report of a supplement’s misleading labelling claims rw de lange, mdip tech graphic design, phd (didactics) department of visual communication, faculty of arts and design, tshwane university of technology, pretoria, south africa corresponding author: rw de lange (delangerw@tut.ac.za) nutritional supplements sometimes contain adulterated and undeclared substances. gabriels et al. reported several incidences where nutritional supplements tested positive for harmful and undeclared substances not indicated on the labels.[1,2] of 138 nutritional supplements commercially available in south africa, 47% tested positive for melamine[1] and 54% for fluoxetine.[2] whilst the median melamine concentration was below the tolerable daily intake (tdi) and the level of fluoxetine contamination low, these substances were not indicated on the labels.[1] melamine is used in plastics and fertilisers, and artificially boosts the protein level in food.[3] fluoxetine, a selective serotonin reuptake inhibitor, is used to treat major depression and bulimia nervos a.[4] a canadian manufacturer of sports supplements promotes a muscleand testosterone-boosting product in south africa via retailers and sports and nutritional outlets. the manufacturer’s advertisements use science sounding efficacy claims for this product, supported by images of hypermasculine men. men suffering from muscle dysmorphia are ideally the intended target audience. this pathological disorder seems to make them more susceptible to appeals for a more muscular physique, and even a brief exposure to the aforementioned imagery, may induce the desired effect.[5] men with muscle dysmorphia are also more likely to experiment with anabolic steroids and other performance-enhancing substances.[6] the objective of this paper is to illustrate how labelling claims of one such product, a purported testosterone booster, potentially mislead consumers by misusing and exaggerating scientific information. this product, as an illustrative example, is but one of many similar products that misuses the same scientific information that appeared in a reproductive and endocrinology journal.[7] the following sections report on the process, claims and evidence supplied by the advertiser, and conclude by questioning these advertising claims. case report the process an email was sent to the company requesting information on the advertising claims. the information provided did not support their advertising claims. a visit to a store that sold the product, followed by a subsequent email, inquired whether the store holds sufficient evidence for supporting the advertising claims. the store manager received information from the company and via email, presented three scientific articles [7, 8, 9] and an evidence and safety summary report as purported evidence for the product’s efficacy claims. the advertiser’s claims were compared against the evidence supplied by the advertiser, and empirical results pertaining to the effect of exogenous d-aspartic acid, the product’s key ingredient, on human testosterone. the term ‘d-aspartic acid’ (and its derivatives) combined with ‘testosterone’ were used as keywords to search for in vivo studies on exogenous d-aspartic acid and its effect on human testosterone levels. however, the search did not reveal any relevant articles in the cochrane database of systematic reviews or reputable urology journals to support a notion that exogenous d-aspartic acid will increase testosterone levels in humans. the aspartates monograph, available from the natural medicines comprehensive database, does not list daspartic acid as a testosterone booster, only stating that people use it for the absorption of supplements and athletic performance. the monograph further cautions that sufficient and reliable information about its safety and effectiveness is not available.[10] the product’s labelling claims the labelling claims for the product is about its efficacy, which is shown on a website and the product’s packaging. these claims are that the product can increase, support, stimulate, amplify, and boost testosterone levels. additional claims are that the product has been clinically researched and that its results are clinically proven. the advertiser’s evidence the first article is a study that deals with rats and not human participants and was therefore dismissed.[8] the second article is a summary of current and previous work on the role of daspartic acid in the nervous and endocrine systems of invertebrates and vertebrates, including mammals.[9] however, it does not cover any studies on the advertised testosterone boosting product or any similar products, nor this paper illustrates how labelling claims of a testosterone booster supplement mislead consumers. the labelling claims misappropriate scientific terminology, exaggerate and misrepresent research as evidence for the product’s purported efficacy. keywords: deceptive advertising, d-aspartic acid, abuse of scientific information s afr j sports med 2020; 32:1-3. doi: 10.17159/2078-516x/2020/v32i1a7426 mailto:delangerw@tut.ac.za https://orcid.org/0000-0003-0008-0998 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7426 case report sajsm vol. 32 no. 1 2020 2 does it look at the increase of testosterone in humans. the third article is a study by topo et al.[7] and could be considered as the only bona fide attempt at providing evidence for this product’s efficacy claims. it reports on the role and molecular mechanism of d-aspartic acid in the release and synthesis of luteinising hormone (lh), and testosterone in humans and in rats. the fourth document is the manufacturer’s own evidence and safety summary report which provides summaries of the three previously mentioned studies and lists an additional eight articles. one of these articles is about the nomenclature and symbolism of amino acids and peptides. the other seven articles are about the claimed safety and health benefits of resveratrol, rhodiola, and vitamins. these eight additional articles do not provide any information to support the product’s testosterone boosting claims. are the claims misleading? the claim regarding d-aspartic acid as a testosterone boosting agent is misleading for several reasons. the advertiser misuses and misrepresents scientific information from the topo et al.[7] study and contradicts the results of other scientific studies. the advertiser’s claims are interrogated below. the first argument is that the advertiser misuses scientific information, particularly tabulated data from the topo et al.[7] study, which are reproduced below. the total testosterone in the topo et al.[7] study increased from a mean of 4.5 (± 0.6) ng/ml serum at zero time to 6.4 (± 0.8) ng/ml after 12 days of use. this then decreased to 5.8 (± 0.6) ng/ml after three days of suspension of d-aspartic acid treatment (for the treatment group). the increase from 4.5 to 6.4 translates to an increase of 42%, a value given on the product’s website to validate their claim of increased testosterone levels. the increase from 4.5 ng/ml to 6.4 ng/ml may be statistically significant but will nonetheless not have any noticeable effect on a user. as such, the results may be statistically significant but clinically insignificant. clinical significance or the practical value of an increase would be when free testosterone levels increase beyond the upper threshold for the consumer’s age group. the topo et al.[7] study also did not calculate and report on free testosterone, only on total testosterone. total testosterone consists of testosterone bound to sex hormone binding globulin (shbg) and free testosterone. free testosterone is a portion of circulating testosterone that crosses cell membranes, exerts a biologic effect and contributes, inter alia, to muscle strength. although there was a statistically significant increase in total testosterone, the increase is still in the lower range of testosterone levels in healthy adult males. it is thus highly unlikely that this small increase, even for men with low levels of testosterone, would produce a discernible effect on their ability to build muscle. what is noteworthy from the topo et al.[7] study is that the volunteers (treatment = 23; placebo = 20) were tested at an in vitro fertilisation clinic. the mean base levels of total testosterone for the treatment and placebo groups were low, namely 4.6 (±0.5) ng/ml and 4.5 (±0.6) ng/ml. although the topo et al.[7] paper states that the test participants were healthy, these base levels are at the lower range of total testosterone for males. the participants did not come from a population of men with total testosterone levels that are spread over the normal range. the normal range of total testosterone levels for men (19-39 years) range from 2.67 ng/ml to 9.29 ng/ml.[11] the second reason for arguing that the claims are misleading is the difference in the time usage of the different products. the participants in the topo et al.[7] study received a solution with d-aspartic acid for 12 days. the advertiser’s product contained 96 capsules which, according to the package design, equates to a 30 day cycle. as such, the results are not directly transferable. the third reason for misleading the consumer is that the topo et al.[7] study used a different product and not the advertiser’s product for testing. the ingredients and the daspartic acid dosage (3120 mg/day) are similar, except that the advertiser added resveratrol and rhodiola. the fourth reason why the claims could be considered as misleading is that they contradict recent studies. a systematic review by roshanzamir and safavi [12] identified 27 relevant studies, of which only four were in vivo human studies. they concluded that ‘more and high-quality randomized controlled trials need to be conducted on d-asp supplementation regarding their ability to increase endogenous levels of testosterone and elucidating the mechanisms of its action in human research’. the fifth reason for misleading the consumer is how the advertiser used bar graphs on their website to illustrate the results of the topo et al.[7] study. the bar graphs only show the upper half of the results and exaggerate the difference between the experimental and placebo groups. the advertiser starts the baseline at 3.5 for lh and 4 for testosterone instead of 0 (i.e. at the bottom of the graph). only showing the upper parts of a bar graph accentuates an otherwise small difference. the advertiser did not mention the decline in the participant’s total testosterone three days after the suspension of d-aspartic acid (the data in the far right column, table 1), and did not indicate this decline in the bar graph. table 1. effects of d-aspartate (d-asp) on luteinising hormone (lh) and testosterone release in human serum (topo et al.)[7] basal levels treatment after six days of d-asp treatment after 12 days of d-asp three days after the suspension of d-asp lh (miu/ml serum) subjects treated with na-d-aspartate 4.2 ± 0.5 4.5 ± 0.6 5.6 ± 0.9* 4.8 ± 0.8 subjects treated with placebo 4.2 ± 0.4 4.3 ± 0.7 4.2 ± 0.6 4.1 ± 0.5 testosterone (ng/ml serum) subjects treated with na-d-aspartate 4.5 ± 0.6 5.2 ± 0.7 6.4 ± 0.8* 5.8 ± 0.6* subjects treated with placebo 4.6 ± 0.5 4.5 ± 0.7 4.7 ± 0.7 4.6 ± 0.7 * values are statistically significant for p < 0.001[7] case report 3 sajsm vol. 32 no. 1 2020 conclusion when confronted with claims such as ‘100% clinically validated’ and ‘clinically researched’ the consumer could infer that the product has been subjected to relevant, unbiased and independent clinical trials, that it is safe and effective, and that there is sufficient scientific evidence to support these claims. from the manufacturer’s supplied information, it is clear that no such trials ever took place. the textual claims and the partial histogram misrepresent and exaggerate the scientific results, potentially misleading consumers. there are limited in vivo human studies on the effect of exogenous d-aspartic acid on testosterone blood serum.[12] the evidence of the small and short duration studies is insufficient to conclude that daspartic acid leads to a substantial and clinically significant increase in testosterone levels. problems related to the supplement industry are not only limited to regulatory matters, adulteration, contamination and unsubstantiated claims, but also include deception and potentially misleading advertising. references 1. gabriels g, lambert m, smith p, et al. melamine contamination in nutritional supplements: is it an alarm bell for the general consumer, athletes, and ‘weekend warriors’? nutr j 2015;14:69 [doi: 10.1186/s12937-015-0055-7] [pmid: 26182916] [pmcid: pmc4504043] 2. gabriels g, lambert m, smith p, et al. fluoxetine contamination in dietary/nutritional supplements (un)bridges the quality of life for the youth to the elderly consumer. med res arch 2018;6(2) [doi:10.18103/mra.v6i2.1616] 3. hau ak-c, kwan th, li pk-t. melamine toxicity and the kidney. j am soc nephrol 2009;20(2):245-250. [doi: 10.1681/asn.2008101065] [pmid: 19193777] 4. rossi a, barraco a, donda p. fluoxetine: a review on evidence based medicine. ann gen hosp psychiatry 2004;3(1):2 [doi: 10.1186/1475-2832-3-2] [pmid: 14962351] [pmcid: pmc356924] 5. leit ra, gray jj, pope hg (jr). the media’s representation of the ideal male body: a cause for muscle dysmorphia? int j eat disord 2002;31(3):334-338. [doi: 10.1002/eat.10019] [pmid: 11920996] 6. pope hg (jr.), gruber aj, choi p, et al. muscle dysmorphia: an unrecognized form of body dysmorphic disorder. psychosomatics 1997;38(6):548-557. [doi: 10.1016/s0033-3182(97)71400-2] [pmid: 9427852] 7. topo e, soricelli a, d’aniello a, et al. the role and molecular mechanism of d-aspartic acid in the release and synthesis of lh and testosterone in humans and rats. reprod biol endocrinol 2009;7:120 [doi: 10.1186/1477-7827-7-120] [pmid: 19860889] [pmcid: pmc2774316] 8. d’aniello a, di fiore mm, d’aniello g, et al. secretion of daspartic acid by the rat testis and its role in endocrinology of the testis and spermatogenesis. febs lett 1998;436(1):23-27. [doi: 10.1016/s0014-5793(98)01087-4] 9. d’aniello a. d-aspartic acid: an endogenous amino acid with an important neuroendocrine role. brain res rev 2007;53(2):215-234. [doi: 10.1016/j.brainresrev.2006.08.005] [pmid: 17118457] 10. aspartates. in: natural medicines comprehensive database [database on the internet] somerville (ma): therapeutic research center; 2014. available from: https://naturalmedicines.therapeuticresearch.com/databases/ food,-herbs-supplements/professional.aspx?productid=12. subscription required to view. 11. travison tg, vesper hw, orwoll e, et al. harmonized reference ranges for circulating testosterone levels in men of four cohort studies in the united states and europe. j clin endocrinol metab 2017;102(4):1161-1173. [doi: 10.1210/jc.2016-2935] [pmid: 28324103] [pmcid: pmc 5460736] 12. roshanzamir f, safavi sm. the putative effects of d-aspartic acid on blood testosterone levels: a systematic review. int j reprod biomed (yazd) 2017;15(1):1-10. [doi: 10.29252/ijrm.15.1.1] [pmid: 28280794] [pmcid: pmc5340133] http://dx.doi.org/10.1016/s0033-3182(97)71400-2 javascript:; javascript:; javascript:; original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license rugby world cup 2019 injury surveillance study cw fuller,1,2 phd; a taylor,2 msc; m douglas,2 be (mech); m raftery,2 mbbs 1 colin fuller consultancy ltd, sutton bonington, united kingdom 2 world rugby, world rugby house, 8-10 pembroke street lower, dublin 2, ireland corresponding author: c fuller (colinfullerconsultancy@gmail.com) athletes competing in contact team sports, such as rugby union, generally experience higher incidences of injury than those competing in non-contact and semi-contact team sports. world rugby, as the international governing body for rugby union, addresses its duty of care by implementing an evidence-based player welfare strategy underpinned by risk management principles.[1-3] central to this player welfare strategy is a comprehensive programme of injury surveillance studies implemented at all major men’s and women’s international rugby tournaments. world rugby’s flagship competition is the men’s rugby world cup (rwc) which is contested every 4 years. the main objectives of the present study were to preserve the world rugby’s programme of injury surveillance studies for the rwc and to compare the rwc 2019 match injury results with those previously published for the 2007, 2011 and 2015 rwcs respectively. methods study definitions and procedures the definitions and procedures used in this study were compliant with the consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union[4] and were also consistent with the procedures used for rwcs 2007, 2011 and 2015 studies.[5-7] world rugby’s institutional ethics committee approved the study and all players taking part in rwc 2019 consented to their data being included in this study. the study took place in japan over a 7 week period commencing on monday 16 september 2019. the first match was played on friday 20 september and the final match on saturday 2 november 2019. three scheduled rwc 2019 group stage matches were cancelled due to adverse weather conditions. six weeks prior to the start of the competition, the 20 participating countries received a guidance document explaining the definitions and reporting procedures. each player’s baseline information, consisting of their normal playing position, date of birth, stature (cm) and body mass (kg), was obtained with data reported as population means (standard deviation). equivalent anthropometric data for players competing in the 2007, 2011 and 2015 rwcs were retrieved from previous publications.[5-7] match exposures were based on 15 players (backs: 7; forwards: 8) being exposed for 80 minutes per match. no allowances were made for players temporarily (as a result of medical treatment) or permanently (due to the receipt of yellow or red cards) missing during a match. none of the matches required extra time. training exposures were recorded based on the number of players (backs, forwards) attending team training sessions, and the number, length (in minutes) and structure of the sessions (preparation: warm up, cooldown, rugby skills: full-contact, semi-contact, non-contact, conditioning: with weights, without weights; other activities). for the rwc, the definition of an injury was: ‘any physical complaint sustained by a player during a rwc match or training session that prevented the player from taking a full part in all training activities or match play for more than 1 day following the day of injury, irrespective of whether match or training sessions were actually scheduled’.[4] the definition of an illness was: ‘any medical condition sustained during the period of the rwc study that prevented the player from taking a full part in all training activities and/or match play for more than 1 day following the day of onset of the illness.’. injuries background: full contact team sports, such as rugby union, have high incidences of injury. injury surveillance studies underpin player welfare programmes in rugby union. objective: to determine the incidence, severity, nature and causes of injuries sustained during the rugby world cup 2019. methods: a prospective, whole population study following the definitions and procedures recommended in the consensus statement for epidemiologic studies in rugby union. output measures included players’ age (years), stature (cm), body mass (kg), playing position, and group-level incidence (injuries/1000 player-hours), severity (daysabsence), injury burden (days absence/1000 player-hours), location (%), type (%) and inciting event (%) of injuries. results: overall incidences of injury were 79.4 match injuries/1000 player-match-hours (95% ci: 67.4 to 93.6) and 1.5 training injuries/1000 player-training-hours (95% ci: 1.0 to 2.3). the overall mean severity of injury was 28.9 (95% ci: 20.0 to 37.8) days absence during matches and 14.8 (95% ci: 4.1 to 25.5) days absence during training. the most common locations and types of match injuries were head/face (22.4%), posterior thigh (12.6%), ligament sprain (21.7%) and muscle strain (20.3%); the ankle (24.0%), posterior thigh (16.0%), muscle strain (44.0%) and ligament sprain (16.0%) were the most common locations and types of injuries during training. tackling (28.7%), collisions (16.9%) and running (16.9%) were responsible for most match injuries and non-contact (36.0%) and contact (32.0%) rugby skills activities for training injuries. conclusion: the incidence, severity, nature and inciting events associated with match and training injuries at rugby world cup 2019 were similar to those reported for rugby world cups 2007, 2011 and 2015. keywords: rugby world cup, injury incidence, injury severity, injury burden, injury risk s afr j sports med 2020;32:1-6. doi: 10.17159/2078-516x/2020/v32i1a8062 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8062 original research sajsm vol. 32 no. 1 2020 2 were reported as recurrences based on the clinical judgement of the injured player’s medical team using the definition: ‘an injury of the same type and at the same site as an index injury and which occurred after the player’s return to full participation from the index injury’.[4] team physicians/physiotherapists were responsible for reporting injuries/illnesses, including the date of injury/illness, the date of return-to-play/training, injury location, type, orchard sports injury coding system (v8) code,[8] and recurrence. all concussion injury reports were cross-checked for consistency with the results reported for match day concussion assessments. when necessary, injuries and illnesses were followed up for three months after the final match of rwc 2019 to obtain return-to-play/training dates. beyond this time, team physicians provided estimated return-to-play/training dates based on a player’s condition at that time (eight injuries). where appropriate, risk factors, such as playing position, time of match injury (0 – 20; 21 – 40+; 41 – 60; 61 – 80+ minutes), activity at time of injury and whether the player was removed from play/training when injured, were reported. in this study, match and training results are reported separately as the number of injuries/1 000 player-hours of exposure with 95% confidence intervals (ci) and injury severities are reported as the mean and median (days; 95% ci). injury burden, the product of incidence and mean severity of injury,[2,9,10] is reported as days-absence/1 000 player-hours (95% ci). equivalent injury data for the 2007, 2011 and 2015 rwcs were retrieved from other published reports.[5-7] statistical analysis statistical comparisons of players’ anthropometric data were calculated using unpaired t-tests.[11] numbers of injuries were compared using chi-squared tests, z-tests were used to compare incidences and mean severities of injury, and mannwhitney u-tests for median severities.[11] trends in values over the four rwcs (2007, 2011, 2015, 2019) were calculated using linear regression analyses and are reported with the slope of the regression lines and r2 values.[11] the number of data comparisons made in this study create the potential for some comparisons to appear as statistically significant at the p≤0.05 level when they may have occurred by chance; for this reason, exact p-values are reported for statistical tests. results six hundred and forty-six players (backs: 284; forwards: 362) representing 20 countries took part in this study and provided baseline anthropometric data (table 1). there were no significant trends in players’ age (backs: slope = 0.024 years/year, r2 = 0.12, p = 0.653; forwards: slope = -0.051 years/year, r2 = 0.46, p = 0.332), stature (backs: slope = 0.018 cm/year, r2 = 0.31, p = 0.443; forwards: slope = -0.068 cm/year, r2 = 0.72, p = 0.151) or body mass (backs: slope = 0.044 kg/year, r2 = 0.08, p = 0.726; forwards: slope = 0.10 kg/year, r2 = 0.50, p = 0.296) over the period 2007 to 2019. incidence, severity and injury burden one hundred and forty-three match injuries (backs: 79; forwards: 64) were sustained during the 45 matches played (group stage: 37; knockout stage: 8), which equate to 1 800 player-match-hours (backs: 840; forwards: 960). over the 7 week period, a total of 16 220 (backs: 7 168; forwards: 9 052) player-training-hours (3 teams did not return player-traininghours) and 25 training injuries (backs: 11; forwards: 14) (all teams returned training injuries) were recorded: incidence of training injuries was based on the results provided by the 17 teams returning both injury and exposure data. no catastrophic spinal or career-ending injuries were reported during the tournament. two illnesses were reported during the tournament (tonsillitis: 1; ear infection: 1). the illnesses correspond to a period prevalence of 0.3% over the period of the competition. no further analysis of these illnesses was undertaken due to their small number. the incidences and severities of match injuries sustained at rwc 2019 are presented in table 2. it shows that the incidence of injury was higher for backs than forwards (difference = 27.4 injuries/1 000 player-match-hours, 95% ci = 1.0 to 53.8, p = 0.041). there were no trends in the incidences of match injuries over the four rwcs for backs (average value = 93.0 injuries/1 000 player-match-hours, slope = 0.94 injuries/1 000 playermatch-hours/year, r2 = 0.49, p = 0.299) or forwards (average value = 79.2 injuries/1 000 player-match-hours, slope = -1.4 injuries/1 000 player-match-hours/year, r2 = 0.72, p = 0.151). there was no significant difference between the severities of match injuries sustained by backs and forwards at rwc 2019 (mean severity: difference = -0.9 days, 95% ci = -19.0 to 17.2, p = 0.920; median severity: difference = -1.0 days, p = 0.992). there was no trend in the severity of match injuries over the four rwcs for backs (mean severity: slope = 1.1 days/year, r2 = 0.70, p = 0.162; median severity: slope = 0.00 days/year, r2 <0.01, p = 1.000) but an increasing trend for forwards (mean severity: slope = 1.4 days/year, r2 = 0.91, p = 0.049; median severity: slope = 0.25 days/year, r2 = 0.83, p = 0.087). the incidences and severities of training injuries sustained at rwc 2019 are also included in table 2. the incidence of training injuries was higher for forwards than backs (difference = 0.26 injuries/1 000 player-training-hours, 95% ci = -0.9 to 1.5, p = 0.674). there were no significant trends in the incidence of table 1. anthropometric data of players competing at rwc 2019 playing position (n) age (years) stature (cm) body mass (kg) backs (n=284) 27.3 (3.5) 182.6 (6.0) 91.2 (9.1) halves (n=101) 27.7 (3.6) 179.0 (5.9) 85.1 (7.5) inside backs (n=76) 27.7 (3.2) 185.5 (4.5) 97.5 (7.0) outside backs (n=107) 26.7 (3.6) 183.9 (5.4) 92.6 (8.1) forwards (n=362) 27.3 (3.8) 188.3 (7.0) 111.8 (9.2) front row (n=169) 27.2 (3.9) 183.7 (4.5) 114.4 (9.1) second row (n=80) 28.0 (3.6) 197.3 (4.6) 114.8 (6.6) back row (n=113) 27.1 (3.7) 188.9 (5.0) 105.8 (7.9) all players (n=646) 27.3 (3.7) 185.8 (7.2) 102.8 (13.7) p value* 1.000 <0.001 <0.001 data are expressed as mean (sd). * indicates backs vs forwards rwc, rugby world cup; n, number of players original research 3 sajsm vol. 32 no. 1 2020 training injuries over the four rwcs from 2007 to 2019 for either backs (average value = 1.9 injuries/1 000 player-training-hours, slope = 0.19 injuries/1 000 player-training-hours/year, r2 = 0.65, p = 0.192) or forwards (average value = 2.3 injuries/1 000 player-training-hours, slope = 0.17 injuries/1 000 player-training-hours/year, r2 = 0.74, p = 0.141). there was no significant difference between the severities of training injuries sustained by backs and forwards (mean severity: difference = 3.7 days, 95% ci = -22.5 to 29.9, p = 0.779; median severity: difference = -1.0 day, p = 0.978). also, there was no trend in the mean severity (slope = -0.22 days/year, r2 = 0.03, p = 0.825) but a decreasing trend in the median severity (slope = -0.38 days/year, r2 =1.00, p <0.001) of training injuries sustained by backs over the period 2007 to 2019. there were no trends for forwards in the mean (slope = -0.54 days/year, r2 = 0.10, p = 0.691) or median (slope = -0.10 days/year, r2 = 0.20, p = 0.553) severities. in total, 4 526 player-days were lost as a consequence of match (backs: 2 251; forwards: 1 879) and training (backs: 196; forwards: 200) injuries sustained in the rwc 2019. the overall match injury burden experienced was 2 296 days absence/1 000 player-match-hours (95% ci = 1 949 to 2 705); with the injury burden for backs (2 680 days absence/1 000 player-matchhours, 95% ci = 2 115 to 3 342) higher than that for forwards (1 957, 95% ci = 1 532 to 2 501, p = 0.061). there were no statistically significant trends in injury burden for backs (slope = 118 days absence/1 000 player-match-hours/year, r2 = 0.65, p = 0.192) or forwards (slope = 73 days absence/1 000 player-match-hours/year, r2 = 0.58, p = 0.236) over the period 2007 to 2019. the overall training injury burden for rwc 2019 was 23 days absence/1 000 player-traininghours (95% ci = 15 to 34). the training injury burden for backs was similar (24 days absence/1 000 player-training-hours, 95% ci = 15 to 34) to that for forwards (22, 95% ci = 13 to 37, p = 0.865). location, type and nature of injuries ninety-one per cent (95% ci = 87.0 to 96.1) of match injuries were acute (backs: 92.3%, 95% ci = 86.4 to 98.2; forwards: 90.6%, 95% ci = 83.5 to 97.8; p=0.719) and 8.5% (95% ci = 3.9 to 13.0) gradual onset (backs: 7.7%, 95% ci = 1.8 to 13.6; forwards: 9.4%, 95% ci = 2.2 to 16.5; p = 0.719). of the 25 training injuries, 84.0% (95% ci = 69.6 to 98.4) were acute (backs: 70.0%, 95% ci = 41.6 to 98.4; forwards: 93.3%, 95% ci = 80.7 to 100; p = 0.119) and 16.0% (95% ci: 1.6 to 30.4) gradual onset (backs: 30.0%, 95% ci = 1.6 to 58.4; forwards: 6.7%, 95% ci = 0 to 19.3; p = 0.119). table 2. incidences and mean and median severities of injuries sustained by backs and forwards during matches and training activity / playing position (n) incidence injuries / 1 000 player-hours (95% ci) severity days (95% ci) mean median match injuries (n) backs (n=79) 94.0 (75.4 – 117.3) 28.5 (17.2 – 39.8) 8 (6 – 11) halves (n=27) 112.5 (77.1 – 164.0) 24.6 (12.6 – 36.6) 7 (6 36) inside backs (n=20) 83.3 (53.8 – 129.2) 55.6 (17.1 – 94.0) 12 (8 67) outside backs (n=32) 88.9 (62.9 – 125.7) 14.9 (7.9 – 21.9) 6.5 (5 10) forwards (n=64) 66.7 (52.2 – 85.2) 29.4 (15.3 – 43.4) 9 (6 15) front row (n=29) 80.6 (56.0 – 115.9) 18.6 (9.4 – 27.7) 8 (4 23) second row (n=8) 33.3 (16.7 – 66.7) 39.0 (0 – 84.0) 14 (4 197) back row (n=27) 75.0 (51.4 – 109.4) 38.1 (9.1 – 67.1) 9 (5 28) all players (n=143) 79.4 (67.4 – 93.6) 28.9 (20.0 – 37.7) 6 (3 13) p-value* 0.041 0.920 0.992 training injuries (n) backs (n=10) 1.4 (0.8 – 2.6) 17.0 (0 – 42.3) 5.5 (2 15) forwards (n=15) 1.7 (1.0 – 2.7) 13.3 (6.5 – 20.1) 7 (2 27) all players (n=25) 1.5 (1.0 – 2.3) 14.8 (4.1 – 25.5) 6 (3 13) p-value* 0.674 0.779 0.978 * indicates backs vs forwards n, number of injuries; ci, confidence interval table 3. match injuries as a function of injury location and playing position injury location % proportion of injuries (95% ci) backs forwards all players head/neck injuries 25.3 (15.7 – 34.9) 28.1 (17.1 – 39.1) 26.6 (19.3 – 33.8) head/face 22.8 (13.5 – 32.0) 21.9 (11.7 – 32.0) 22.4 (15.5 – 29.2) neck/cervical spine 2.5 (0 – 6.0) 6.3 (0.3 – 12.2) 4.2 (0.9 – 7.5) upper limb injuries 16.5 (8.3 – 24.6) 20.3 (10.5 – 30.2) 18.2 (11.9 – 24.5) shoulder/clavicle 6.3 (1.0 – 11.7) 9.4 (2.2 – 16.5) 7.7 (3.3 – 12.1) upper arm 0.0 1.6 (0 – 4.6) 0.7 (0 – 2.1) elbow 0.0 4.7 (0 – 9.9) 2.1 (0 – 4.4) forearm 1.3 (0 – 3.7) 1.6 (0 – 4.6) 1.4 (0 – 3.3) wrist/hand/fingers 8.9 (2.6 – 15.1) 3.1 (0 – 7.4) 6.3 (2.3 – 10.3) trunk injuries 7.6 (1.8 – 13.4) 9.4 (2.2 – 16.5) 8.4 (3.8 – 12.9) upper back/sternum/ribs 3.8 (0 – 8.0) 4.7 (0 – 9.9) 4.2 (0.9 – 7.5) abdomen 0.0 0.0 0.0 lower back/pelvis 3.8 (0 – 8.0) 4.7 (0 – 9.9) 4.2 (0.9 – 7.5) lower limb injuries 50.6 (39.6 – 61.7) 42.2 (30.1 – 54.3) 46.9 (38.7 – 55.0) hip/groin 1.3 (0 – 3.7) 0.0 0.7 (0 – 2.1) anterior thigh 10.1 (3.5 – 16.8) 3.1 (0 – 7.4) 7.0 (2.8 – 11.2) posterior thigh 13.9 (6.3 – 21.6) 10.9 (3.3 – 18.6) 12.6 (7.2 – 18.0) knee 8.9 (2.6 – 15.1) 15.6 (6.7 – 24.5) 11.9 (6.6 – 17.2) lower leg/achilles 3.8 (0 – 8.0) 6.3 (0.3 – 12.2) 4.9 (1.4 – 8.4) ankle 8.9 (2.6 – 15.1) 6.3 (0.3 – 12.2) 7.7 (3.3 – 12.1) foot/toe 3.8 (0 – 8.0) 0.0 2.1 (0 – 4.4) ci, confidence interval original research sajsm vol. 32 no. 1 2020 4 the proportions of match injuries sustained as functions of location and type of injury are presented in tables 3 and 4. there were no statistically significant trends in the proportions of the main injury locations or injury types sustained over the period 2007 to 2019 for backs or forwards, apart from an increasing trend in the proportion of head/neck injuries sustained by backs (slope = 1.6%/year, r2 = 0.95, p = 0.028). the six most common match injuries and the six match injuries responsible for most days absence are presented in table 5. the knee ligament group of injuries includes medial (5), anterior cruciate (1), posterior cruciate (1) and complex (1) ligament injuries. as a consequence of their match injuries, 31.0% (95% ci: 23.4 to 49.1) of players (backs: 34.6%, 95% ci 24.1 to 45.2; forwards: 26.6%, 95% ci 15.7 to 37.4; p = 0.303) were removed from play immediately, 20.4% (95% ci 13.8 to 36.2) of players (backs: 15.4%, 95% ci 7.4 to 23.4; forwards: 26.6%, 95% ci 15.7 to 37.4; p = 0.101) were removed later in the game and 48.6% (95% ci 40.4 to 68.2) of players (backs: 50.0%, 95% ci 38.9 to 61.1; forwards: 46.9%, 95% ci 34.6 to 59.1; p = 0.711) remained on the pitch until the end of the game. of the 22 match concussions reported, 17 players (77.3%) were removed from play immediately, three (13.6%) players were removed later in the game and two (9.1%) players completed the game. seventy-six per cent of training injuries (ankle: 24.0%, 95% ci = 7.3 to 40.7; posterior thigh: 16.0%, 95% ci = 1.6 to 30.4) were lower limb injuries and sixty-four per cent were muscle/tendon or joint (non-bone) injuries (muscle strains: 44.0%, 95% ci = 24.5 to 63.5; ligament sprains: 16.0%, 95% ci = 1.6 to 30.4). one training injury was a concussion which was identified during the training session and the player was removed immediately. a more detailed analysis of the training injuries was not undertaken due to the small number (n=25) reported. risk factors for match and training injuries there were no significant differences in the anthropometric characteristics of injured players compared to the overall sample of players for age (backs: difference = 0.3 years, 95% ci = -0.5 to 1.1 years, p = 0.478; forwards: difference = 0.1 years, 95% ci = -0.8 to 1.0, p = 0.834), stature (backs: difference = +0.7 cm, 95% ci = -0.8 to +2.2, p = 0.347; forwards: difference = -1.2 cm, 95% ci = -2.7 to 0.5, p = 0.197) or body mass (backs: difference = 0.75, 95% ci = -1.5 to 3.1, p = 0.478; forwards: difference = 0.0, 95% ci = -2.1 to 2.1, p = 1.000). backs sustained a higher proportion of injuries in the second half of matches compared to the first half but there was little difference for forwards (backs: first half = 37.0%, 95% ci = 25.9 to 48.1, second half = 63.0%, 95% ci = 51.9 to 74.1, p=0.026; forwards: first half = 47.5%, 95% ci = 34.7 to 60.2, second half = 52.5%, 95% ci = 39.8 to 65.3, p=0.696). contact events were responsible for the majority of match injuries (contact: 76.0%, 95% ci: 69.6 to 82.4; non-contact: 24.0%, 95% ci: 17.6 to 30.4) and training injuries (contact: 70.0%, 95%ci: 49.9 to 90.1; non-contact: 30.0%, 95% ci: 9.9 to 50.1). the specific table 4. match injuries as a function of injury type and playing position injury type % proportion of injuries (95% ci) backs forwards all players bone injuries 10.1 (3.5 – 16.8) 3.1 (0 – 7.4) 7.0 (2.8 – 11.2) fracture 10.1 (3.5 – 16.8) 3.1 (0 – 7.4) 7.0 (2.8 – 11.2) other bone injury 0.0 0.0 0.0 c/pns injuries 15.2 (7.3 – 23.1) 20.3 (10.5 – 30.2) 17.5 (11.3 – 23.7) concussion 15.2 (7.3 – 23.1) 15.6 (6.7 – 24.5) 15.4 (9.5 – 21.3) nerve injury 0.0 4.7 (0 – 9.9) 2.1 (0 – 4.4) joint (non-bone) injuries 27.8 (18.0 – 37.7) 31.3 (19.9 – 42.6) 29.4 (21.9 – 36.8) dislocation/subluxation 3.8 (0 – 8.0) 1.6 (0 – 4.6) 2.8 (0.1 – 5.5) lesion meniscus/disc 5.1 (0.2 – 9.9) 4.7 (0 – 9.9) 4.9 (1.4 – 8.4) sprain/ligament 19.0 (10.3 – 27.6) 25.0 (14.4 – 35.6) 21.7 (14.9 – 28.4) muscle/tendon injuries 38.0 (27.3 – 48.7) 34.4 (22.7 – 46.0) 36.4 (28.5 – 44.2) haematoma/bruise 13.9 (6.3 – 21.6) 12.5 (4.4 – 20.6) 13.3 (7.7 – 18.9) muscle strain/cramp 20.3 (11.4 – 29.1) 20.3 (10.5 – 30.2) 20.3 (13.7 – 26.9) tendon injuries 3.8 (0 – 8.0) 1.6 (0 – 4.6) 2.8 (0.1 – 5.5) skin injuries 1.3 (0 – 3.7) 4.7 (0 – 9.9) 2.8 (0.1 – 5.5) abrasion 0.0 0.0 0.0 laceration 1.3 (0 – 3.7) 4.7 (0 – 9.9) 2.8 (0.1 – 5.5) pain (undiagnosed) 3.8 (0 – 8.0) 3.1 (0 – 7.4) 3.5 (0.5 – 6.5) other injuries 3.8 (0 – 8.0) 3.1 (0 – 7.4) 3.5 (0.5 – 6.5) c/pns, central and peripheral nervous system; ci, confidence interval table 5. the most common match injuries and the match injuries causing most days absence most common injuries injuries causing most days absence injury n % days absence injury days absence % n concussion 22 15.4 363 knee ligament 935 22.6 8 hamstring strain 14 9.8 467 knee cartilage injury 495 12.0 5 knee ligament 8 5.6 935 hamstring strain 467 11.3 14 ankle ligament 7 4.9 95 concussion 363 8.8 22 thigh haematoma 7 4.9 43 shoulder dislocation 316 7.7 2 knee cartilage injury 5 3.5 495 calf muscle strain 194 4.7 4 all injuries 143 4 130 all injuries 4 130 143 n, number of injuries; %, proportion of all injuries original research 5 sajsm vol. 32 no. 1 2020 activities associated with the match injuries are shown in table 6. there were no statistically significant trends in the proportion of injuries sustained for any of the match activities in rwc games over the period 2007 to 2019 for backs or forwards, apart from an increasing trend in the proportion of tackling injuries sustained by backs (slope = 1.7%/year, r2 = 0.95, p = 0.028). discussion consistent with previous rwc studies,[5-7] forwards were significantly taller and heavier than backs in rwc 2019 but there was no difference in the age of backs and forwards. there was no evidence of significant trends in the age, stature or body mass of backs or forwards over the period rwc 2007 to rwc 2019. the stature and body mass of rwc players over this 12 year period were similar to values reported in previous studies of elite northern and southern hemisphere players.[12,13] although backs and forwards taking part in the rwc were on average two to three years older than players competing at the elite club level,[12] this is to be expected as the more experienced players are generally selected for the national teams. the incidence of match injury for backs was higher than that recorded for forwards in rwc 2019, which has also been reported in previous rwcs.[5-7] the lower overall incidence of match injuries recorded in rwc 2019 compared to rwc 2015 is welcome with the reduction mainly attributable to the lower incidence of injuries recorded by forwards. although the incidences of training injuries for both backs and forwards were higher during rwc 2019, compared with rwc 2015, the long-term downward trend in the incidence of training injuries remains. there were no significant differences between the severities of match injuries sustained by backs and forwards during rwc 2019. the increasing trends in mean severity of match injuries reported previously for backs and forwards in the period rwc 2007 to rwc 2015,[7] did not continue in rwc 2019; however, mean severity values remain at the higher end of the previous range. median severity values have changed little for backs and forwards over the rwc 2007 to rwc 2019 period, which indicates that the main reason for the increase in mean severity continues to be related to small increases in the number of high severity injuries. the overall lower match injury incidence recorded in rwc 2019, compared to rwc 2015, resulted in a decrease in players’ match injury burden (rwc 2019: 4 130 player-daysabsence; rwc 2015: 5 152 player-daysabsence);[7] however, player-days-absence in rwc 2019 remained above those reported for rwc 2011 (4 047 player-days-absence) and rwc 2007 (2 366 player-days-absence).[6,7] the injury burden from training injuries sustained in rwc 2019 (396 player-daysabsence) remained similar to that reported for rwc 2015 (287 player-days-absence) but were much lower than those reported for rwc 2007 (1 065 player-days-absence) and rwc 2011 (940 player-daysabsence).[6,7] the head/face (21.9%), posterior thigh (10.9%) and knee (15.6%) are the sites of almost 50% of all injuries sustained, whilst ligament sprains (21.7%), muscle strains (20.3%) and concussions (15.4%) describe almost 60% of all injury types sustained. while the two most common specific injuries (concussion: 15.4%; hamstring muscle strain: 9.8%) accounted for approximately 25% of all injuries sustained in rwc 2019, they were not responsible for the most time-loss injuries, as knee ligament (22.6%) and knee cartilage (12.0%) injuries together accounted for nearly 35% of all time lost. although there was a small increase in match concussions in rwc 2019 compared to rwc 2015 (15.5% v 13.9%; p = 0.582), when expressed as a percentage of all match injuries sustained, the incidence of concussion was slightly lower in rwc 2019 than rwc 2015 (12.2 v 12.5 injuries/1 000 player-match-hours; p = 0.912) due to the overall reduction in injury incidence in rwc 2019. a comparison of concussions sustained in the 2007, 2011 and 2015 rwcs has been presented previously.[7]. despite concussions currently being the focus for injury prevention in rugby, knee ligament, knee cartilage and hamstring injuries together are responsible for nearly 50% of all player-daysabsence. these injuries, therefore, must not be overlooked, as they are likely to provide a greater return on any investment in injury prevention.[14] the tackle (tackling: 28.7%; being tackled: 19.1%) was responsible for 47.8% of all injuries sustained in rwc 2019, which continues the upward trend in the proportion of injuries sustained in the tackle observed in previous rwcs (2007: 29.2%; 2011: 40.1%; 2015: 45.9%)[5-7]. a number of previous studies have investigated relationships between match injuries and specific match activities[15-18]. this study has a number of strengths: it is a prospective, whole population study following the recommendations of the consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union.[4] the study describes the sample populations in terms of players’ position, age, stature and body mass. injuries and illnesses were diagnosed and reported by qualified team doctors and table 6. match injuries sustained as a function of playing position and match activity match activity % proportion of injuries (95% ci) backs forwards all players tackling 29.3 (19.0 – 39.6) 27.9 (16.6 – 39.1) 28.7 (21.1 – 36.3) tackled 18.7 (9.8 – 27.5) 19.7 (9.7 – 29.6) 19.1 (12.5 – 25.7) running 21.3 (12.1 – 30.6) 11.5 (3.5 – 19.5) 16.9 (10.6 – 23.2) collision* 18.7 (9.8 – 27.5) 14.8 (5.9 – 23.7) 16.9 (10.6 – 23.2) ruck 4.0 (0 – 8.4) 6.6 (0.3 – 12.8) 5.1 (1.4 – 8.9) scrum 0.0 8.2 (1.3 – 15.1) 3.7 (0.5 – 6.8) maul 0.0 4.9 (0 – 10.3) 2.2 (0 – 4.7) kicking 2.7 (0 – 6.3) 0.0 1.5 (0 – 3.5) lineout 0.0 0.0 0.0 other 5.3 (0.2 – 10.4) 6.6 (0.3 – 12.8) 5.9 (1.9 – 9.8) * accidental and non-accidental collisions; ci, confidence interval original research sajsm vol. 32 no. 1 2020 6 physiotherapists, using an established reporting protocol and the orchard sports injury classification system. furthermore, all injuries and illnesses were followed up post-tournament in order to obtain final diagnoses and return to play dates. in conclusion, the results from this study confirm a high incidence and severity of injury within international rugby but the incidence, nature and inciting events for injuries in rwc 2019 were broadly similar to those reported previously for rwc 2007, 2011 and 2015. conflict of interest: cwf provides risk management consultancy services to world rugby. md is world rugby’s research, turf and equipment manager. mr was world rugby’s chief medical officer at the time of rwc 2019. at has no competing interest. source of funding: the study was funded by world rugby. the funders had no role in the study design, data collection and analysis or the preparation of the manuscript. acknowledgements: the authors would like to acknowledge the valuable support provided by medical staff from the 20 participating national teams who provided injury data for this study: f badessi, g botto, c cosgrave, m deasy, f fujita, d gutierrez, w harrington, c jenkins, w macdonald, j mampane, p mathema, v morkel, k ng, t page, p poloniati, s pope, j robson, m santurio, b savill, n shamatava, s takamori, m white, d williams, o withers, m yamada, r youngs. author contributions: cwf designed the study, analysed and interpreted the data, and wrote the initial draft and final version of the paper. at contributed to the design of the study, collected the data and critically assessed the initial draft of the paper. md contributed to the design of the study, collected the data, and critically assessed the initial draft of the paper. mr contributed to the design of the study, interpretation of the results, and critically assessed the initial draft of the paper. all authors approved the final version of the paper. references 1. fuller c, drawer s. the application of risk management in sport. sports med 2004; 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[doi: 10.1007/s40279-0180913-5] [pmid: 29623603] 11. kirkwood br, sterne ja. essential medical statistics. 2nd ed. oxford: wiley-blackwell 2003. 12. fuller cw, taylor ae, brooks jh, et al. changes in the stature, body mass and age of english professional rugby players: a 10year review. j sports sci 2013; 31(7): 795-802. [doi: 10.1080/02640414.2012.753156] [pmid: 23244349] 13. zemski aj, slater gj, broad em. body composition characteristics of elite australian rugby union athletes according to playing position and ethnicity. j sports sci 2015; 33(9): 970-978. [doi: 10.1080/02640414.2014.977937] [pmid: 25553727] 14. fuller cw. assessing the return on investment of injury prevention procedures in professional football. sports med 2019; 49(4): 621-629. [doi: 10.1007/s40279-019-01083-z] [pmid: 30838519] 15. fuller cw, brooks jh, cancea rj, et al. contact events in rugby union and their propensity to cause injury. br j sports med 2007; 41(12): 862-867. 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[doi:10.1249/mss.0b013e3181c07b5b] https://doi.org/10.2165/00007256-200434060-00001 https://doi.org/10.2165/00007256-200434060-00001 https://doi.org/10.1097/jsm.0b013e31805930b0 https://playerwelfare.worldrugby.org/%20?subsection=66 https://playerwelfare.worldrugby.org/%20?subsection=66 original research 1 sajsm vol. 30 no. 1 2018 a comparison of the physical demands of a one-day cricket game and the training sessions of provincial cricket players using global positioning system tracking software z webster, ma (sport, rec and ex science), a l travill, phd department of sport, recreation and exercise science, university of the western cape, cape town, south africa corresponding author: a l travill (atravill@uwc.ac.za) cricket is a multifaceted, highly technical sport, and coaches tend to focus on the improvement of individual skills during the training sessions while little attention is given to the physical demands of the game. however, the sport has evolved over the last few decades and the physical demands in the game have risen considerably, with a clustering of fixtures and many more competitions being played.[1] this has compelled coaches to focus more on the physical demands of the game. in a sport such as cricket, the challenge is even more complex as it consists of different disciplines, each with its own distinct movement patterns, physical and physiological demands.[2] furthermore, there are three major formats of the game, i.e. multi-day games, one-day games (odg) and t20 games. the latter two are shorter formats of the game which include more intense movements and consequently impose dissimilar physical and physiological demands on players.[3,4] training should consequently be specifically geared towards the physical demands of these different formats. in order to do this, sports scientists and coaches require accurate information and an in-depth understanding of the physical demands of the different sub-disciplines and formats of cricket in order to develop and design appropriate training strategies and programmes. in general, there are a wide variety of techniques available to assess and estimate the physiological and physical demands of sports, ranging from simple pen-and-paper methods and video recordings, to sophisticated electronic tracking devices.[5] timemotion analysis using global position analysis (gps) is the most widespread approach for quantifying the physical demands of sports, including cricket.[6,7] heart rate is a physiological variable which is commonly used to determine the internal training load.[8] previous research which reported on heart rate responses to workload, highlights the irregular nature of the types of demand placed on cricketers.[9] information regarding the physical demands of cricket has been mostly obtained from research conducted in simulated settings which, in theory, is not a true reflection of the demands of the real match situation.[10] the game of cricket has been considerably improved mainly through the introduction of injury prevention mechanisms among the players and the enhancement of performances by means of technology and sports sciences.[11] although cricket is one of the world's major team sports, there has been little attention given to the physical demands of the game in research[12] for the different game formats. as previously mentioned, this information has been obtained from research conducted in simulated settings, which is not a true reflection of the real game situation. furthermore, there is a dearth of information on the physical demands of cricket training in particular, compared to that of the match situation. the purpose of this study was therefore to assess and compare the physical demands of an odg and a cricket training session of provincial players across the different sub-disciplines (batting, fast bowling, spin bowling, fielding and wicketkeeping) using gps units. methods study design this is a descriptive and comparative cross-sectional study of the movement patterns of provincial cricket players. background: cricket is a highly technical skills-based game and coaches consequently focus on the improvement of skills during training sessions. however, a certain level of physical fitness is required to execute these skills optimally. coaches tend to give little focused attention to the development of physical fitness during training, which could lead to players being physically unprepared for the demands of a game. objective: the purpose of this study was to assess and compare the physical demands of a one-day cricket game and a training session of provincial cricket players, using global positioning system units. methods: nineteen male provincial cricketers participated in the research. the participants were classified into five subdisciplines, namely, batting, fast bowling, spin bowling, fielding and wicketkeeping. the study employed a descriptive and comparative design as it essentially collected numerical data from global positioning system units to describe and compare the physical demands of a one-day game of cricket and a training session preceding these games. the variables used in the study included total distances travelled in the game which were divided into five movement categories, i.e. walking, jogging, running, striding and sprinting. also included were average and maximum heart rates, number of sprints and average sprint distances. results: there were significant differences across all subdisciplines and movement categories during training and the one-day game for provincial cricket players. batsmen showed the greatest discrepancies between training and the game for all high-intensity movements (p<0.05). conclusion: the findings of this study highlight the different physical and physiological demands placed on players in the various sub-disciplines during training and the one-day game. the current study found the major disparity between training and the one-day game was amongst the batsmen. keywords: high-intensity movements, low-intensity activities, physical exertion, sub-disciplines s afr j sports med 2018;30:1-6. doi: 10.17159/2078-516x/2018/v30i1a5053 http://dx.doi.org/10.17159/2078-516x/2018/v30i1a5053 original research sajsm vol. 30 no. 1 2018 2 participants the sample was purposively selected and consisted of 19 male provincial cricket players. players were classified into the five areas of play, namely: batting (n=6), fast bowling (n=5), spin bowling (n=2), fielding (n=4) and wicketkeeping (n=2) for comparative purposes. in this research, all seam bowlers were classified as fast bowlers. the playing positions are not mutually exclusive as the same player fulfils various roles during the game. data collected for bowlers and batters include the entire time they spent on the playing field. the “fielder” category included players who were not bowling or wicketkeeping during a fielding innings. fielding was not subdivided into a specific fielding position. the data were collected at their home playing ground or regular training facility. ethical clearance the methods and ethics of this research were approved by the biomedical research committee of the university of the western cape. all participants provided written, signed consent to participate in the research. the registration number of the project is 15/6/34. research procedure data were collected during one official provincial odg, as well as during the one training session leading up to the game. the data were then categorised into the five sub-disciplines or areas of play specified. however, bowling was further subdivided into fast bowlers and spin bowlers for comparative purposes. the data reflects the total time the players spent on the field during the entire game or training session. gps units (gp sports, minimaxx v2.0, 10hz sampling rate) were attached to players by means of supporting harnesses for the duration of the game and in the training sessions. recent research found the 10 hz sampling frequency was up to six times more reliable at measuring instantaneous velocity than the five hz units[13]. while research investigating the validity and inter-unit reliability of 10 hz and 15 hz gps units for assessing athlete movement demands found that, in general, the 10 hz gps units measured movement demands with greater validity and inter-unit reliability than the 15 hz units.[14] the unit used in the current study was able to measure maximum speed, average speed, distance travelled, position in the game, maximum heart rate and average heart rate. the units were splash-proof, weighed 110 g and used a rechargeable li-ion battery. the unit included a gps sports analysis system. it was switched on at the commencement of activity and switched off at the end of activity. this was done so that the researcher could avoid readings of inactivity outside of the field of play and those affecting the training and game data. warm-up and cool-down sessions were excluded from the data collection process. the gps system generated real-time data and recorded performance on a movement tracking system. data were downloaded onto a computer for analysis after the training session and match. the variables used in this study were time/duration of the session, total distances travelled, maximum heart rate, average heart rate, number of sprints and average sprint distances. although there were a number of internal indicators of the physiological stress of movement, including metabolic responses and blood lactate concentrations, heart rate measurement emerged as one of the more popular approaches to monitor the internal responses of the physiological demands of cricket[8] which was used in the present study. the distances travelled by the players were divided into five movement categories, namely, standing and walking [0.0 – 2.0 m/s], jogging [2.0 – 3.5 m/s], running [3.5 4.0 m/s], striding [4.0 – 5.0 m/s], and sprinting [>5 m/s]. the movement categories were pre-programmed and are in line with those used by other researchers.[4] once the data were downloaded, it was categorised into these variables for statistical analysis. walking and jogging were considered low-intensity activities, while running, striding and sprinting were categorised as highintensity activities. statistical analysis the statistical analysis was conducted by means of spss v23 software. data are presented as means and standard deviations. a paired samples t-test was used to assess whether there were differences between the physical exertion during training and an odg. a one-way anova was conducted to test for differences between the sub-disciplines (batsmen, fast bowlers, spin bowlers, fielders, and wicketkeepers) in terms of their training loads and match loads. a post hoc tukey test was done to establish which means were significantly different from each other. the level of significance was set at p<0.05. box plots were produced for average and maximum heart rates to illustrate the spread of the scores and the differences between training and game heart rates. effect sizes were calculated to quantify the size of the differences between training and the odg. effect sizes were interpreted using cohen’s guidelines[15] (0.2=small; 0.5=medium; 0.8=large and 1.3=very large). results movement patterns the distances covered by the cricketers during training and the odg are shown in table 1. the lowest distances recorded were for batsmen, with 751 m (116 m) and 1469 m (1057 m) for training and the odg respectively. all the high-intensity movement components for batsmen (running, striding and sprinting) were significantly higher during the game compared to the training session (p<0.05). walking on the field made up 60% of the time for fast bowlers compared to 93% for wicketkeepers. fast bowlers also showed the greatest differences in the distances in training and the odg covered in the low-intensity movement categories. the percentages of the distances covered in the low-intensity movements were 56%, 9% and 3% for walking, jogging and running respectively during training, during an odg the percentages for walking, jogging and running respectively were 68%, 11% and 3%. for the high-intensity movements, striding is closely matched between training (6%) and a game (4%), while sprinting during training is 23% of the distance covered and 13% for a game. the high-intensity movement patterns of fast bowlers did not differ between the odg and training. this shows that physical exertion in terms of original research 3 sajsm vol. 30 no. 1 2018 table 1. mean distances covered by provincial cricket players during a training session and one-day game (odg) per playing position and per movement category variable total distance (m) mean (sd) walking (m) mean (sd) jogging (m) mean (sd) running (m) mean (sd) striding (m) mean (sd) sprinting (m) mean (sd) batsmen training 751 (116) 611 (131) 131 (106) 8 (19)* 0.4 (1)* 0* odg effect size 1469 (1057) 0.9 933 (640) 0.7 169 (116) 0.3 75 (58) 1.2 133 (162) 1.3 159 (150) 1.2 fast bowlers training 2397 (482)* 1374 (290)* 224 (17)* 10 (13) 148 (59) 674 (156) odg effect size 8790 (3832) 1.7 6234 (2886) 1.7 1347 (685) 1.6 143 (45) 1.3 291 (133) 1.1 567 (203) 0.7 spin bowlers training 3008 (81) 2397 (92) 600 (158) 26 (35)* 1 (1)* 0 (0) odg effect size 4353 (2842) 0.7 3025 (1964) 0.5 1083 (801) 0.9 10 (13) 1.6 74 (1) 1.7 26 (29) 1.1 fielders training 1308 (560)* 702 (135)* 395 (396) 65 (75) 120 (190) 26 (16)* odg effect size 5457 (2247) 1.5 4197 (1223) 1.7 855 (640) 0.8 153 (205) 0.6 129 (151) 0.1 115 (62) 1.4 wicketkeepers 3835 (2202) 2840 (1612) 894 (516) 69 (58) 9.3 (51) 3 (3) data expressed as mean (± sd). *denotes significant differences between training and odg distances covered p<0.5. odg, one day game table 2. comparison of distances covered by provincial batsmen, fast bowlers, spin bowlers and fielders during a oneday game variable batsmen mean fast bowlers mean spin bowlers mean fielders mean p-value total distance (m) 1469fb, f 8790bat 4353 5457bat 0.000* walking (m) 933fb, f 6234bat 3025 4197bat 0.000* jogging (m) 169fb 1347bat 1083 855 0.003* running (m) 75 143 10 153 0.146 striding (m) 133 291 74 129 0.050 sprinting (m) 159fb 567bat, sb, f 25fb 115fb 0.000* * the mean difference is significant at the 0.05 level. superscripts identify the significance between the different groups. bat, batsman; fb, fast bowlers; sb, spin bowlers; f, fielders * 0 5 10 15 20 25 batters fast bowlers spin bowlers fielders n u m b e r o f s p r in ts playing positions training odg 0 5 10 15 20 25 30 batters fast bowlers spin bowlers fielders a v e r a g e s p r in t d is ta n c e ( m ) playing positions training odg fig. 2. average sprint distance per playing position during training and the odg. odg, one day game. fig. 1. number of sprints per playing position during training and the odg. * mean difference is significant at the 0.05 level. odg, one day game original research sajsm vol. 30 no. 1 2018 4 movement patterns for provincial fast bowlers during training is closely matched for highand low-intensity movement categories spin bowlers covered more than twice the absolute total distance during the odg (7100 m) in comparison to training (2400 m). similar percentages of distance in all movement categories were covered between training and the odg. the majority of movement for spin bowlers was spent on lowintensity activities during training with 76%, 22% and 1% for walking, jogging and running respectively, while 72%, 20%, and 3% were covered in the same categories during an odg. for high-intensity movements, spin bowlers covered 0.5% and 2% of the distance during striding and sprinting respectively while covering 0.3% and 2% for the same movements during an odg. it can be deduced that physical exertion in terms of movement categories for spin bowlers during training is closely matched to all the movement categories of an odg. effect sizes show that the differences between training and the odg for all sub-disciplines and for all movement categories were between medium and very large, with the majority falling in the very large category. most of the differences between sub-disciplines were recorded for batsmen and fast bowlers (table 2). fast bowlers differed from all other disciplines in terms of the sprint distances covered (p<0.05). figures 1 and 2 summarise the average number of sprints and sprint distances completed by the cricket players per playing position during training compared to the odg. batters completed the biggest number of sprints during the odg; however, this is not matched in their training, where no sprinting distances were recorded. although batsmen perform a greater number of sprints during the game compared to fast bowlers, their runs are shorter on average (12.8 m) and their top speeds slower (24 km/h). batsmen are the only players whose training sprint speeds do not match their game maximum speeds (p<0.05). physiological responses the box plots depict the differences in the median, minimum and maximum heart rates of the cricket players during a training session compared to the odg per subdiscipline (figures 3 and 4). from the box plots, it can be seen that there are two outliers, one for the average heart rate of fast bowlers during training and the second one for the maximum heart rate of fast bowlers also during training. the distributions for some of sub-disciplines for both the average and maximum heart rates are significantly different. higher average heart rates were recorded for all playing positions during the odg compared to the training sessions, except for the fast bowlers. however, only the batsmen had significantly higher average and maximum heart rates (p<0.05). discussion the research in this study found a great discrepancy between fig. 4. maximum heart rate (bpm) comparisons per playing position during training and the odg. open circle indicates an outlier. spin b, spin bowler; fast b, fast bowler; odg, one day game fig. 3. average heart rate (bpm) comparisons per playing position during training and the odg. open circle indicates an outlier; * indicates an extreme outlier. spin b, spin bowler; fast b, fast bowler; odg, one day game original research 5 sajsm vol. 30 no. 1 2018 the movement demands of the odg and the training sessions, especially in the high-intensity categories. the effect sizes showed that most differences in the movement patterns for all playing positons between training and the odg were large or very large. the size differences for four of the six movement categories of fast bowlers were found to be very large, with the remaining two being large and medium respectively. the disparity between training and the game is most pronounced amongst batsmen. it is the only sub-discipline where all high-intensity movement patterns differed significantly between training and the odg. results further showed that the batsmen did no sprinting during training. although high levels of skill are critical to the success of batsmen, they do need to do a significant amount of sprinting between the wickets at relatively high speeds. it is important to note that the sprints by batsmen are performed with protective gear and playing implements, which places additional physical demands on the players. the lower maximum speeds recorded for batsmen could be as a consequence of their protective clothing worn. the mismatch between the movement patterns of batsmen during training and the odg could have serious performance consequences for them given that the estimated distance that can be covered by a batsman who scores 100 runs is 3200 m[1], while batsmen who bat throughout an entire innings can cover as much as 8700 m.[4] the lack of high-intensity training for batsmen suggests that the focus during their training is mainly on skill enhancement.[12] similar to previous research,[16] the total distance covered by batsmen in the current study consisted predominantly of low-intensity activities which did not differ between training and the game. the non-alignment of the physical demands placed on batsmen during training compared to the odg is also reflected in the reported physiological parameters. they are the only players who had significantly higher maximum and average heart rates during the odg (p<.05). their maximum heart rates during the odg ranged between 141 and 206 bt.min-1 (mean 180 bt.min-1) and between 127 and 189 bt.min-1 (mean 162 bt.min-1) during training. their average heart rates also differed between training and the odg, namely, 121 and 151 bt.min-1 respectively. these variances could be as a consequence of pervasive training methods, which may not best emulate the demands of cricket matches. fast bowlers covered the greatest absolute total distances in most movement categories compared to most of the other subdisciplines. they covered the greatest sprinting distances at the highest average speeds. the sprinting demands of their training in terms of high-intensity movement patterns and maximum (193 bt.min-1) and average heart rates (170 bt.min-1) matches the demands of the odg. net-based training adequately simulates the high-intensity movement patterns for fast bowlers. this could be the reason why no differences were found between the high-intensity movements in the training and the odg. these findings are in line with those reported in previous research[17] showing that fast bowlers consistently performed at greater intensities than the other sub-disciplines. spin bowlers performed at a much lower intensity compared to the fast bowlers during both training and the game. the differences can be ascribed to movements associated with the various types of delivery, especially regarding their run-ups. the major discrepancies between training and the game for spin bowlers were recorded mainly in the highintensity movement categories (running and striding). fielders, similar to fast bowlers, covered significantly greater total distances during the game compared to in training. the significant differences recorded for sprinting could be as a result of the increased effort made by fielders to save runs during the game. this also highlights the demand for more high-intensity movements during training for fielders to meet the demands of an odg, a finding supported by previous research.[18] it should be kept in mind that the differences between the distances covered during training and the odg could be ascribed to variations in the duration of training sessions compared to a game. furthermore, various researchers[4,7] agreed that the volume and duration of movement that a player in a particular position undertook depends largely on the game’s circumstances. however, it is important to note that players are prepared to deal with especially the high-intensity movement demands of the game. according to current research[16], high-intensity movements occupy a relatively small percentage of the total distances covered during a game, and could therefore be easily accommodated in the shorter training sessions. cricket, compared to most other field sports, consists mainly of low-intensity activities, such as walking. however, the shorter formats of cricket games do include more frequent highintensity movements for all sub-disciplines.[3] this implies that high-intensity training should constitute the major part of training sessions even for the shorter formats of the game. this is supported by previous research[4] which found that the time spent sprinting per hour is 50-100% more in odg than in multiday cricket and that they further require greater intensity per unit of time. there are two main training formats employed by cricket coaches of which the more common format is net-based training where the focus is skills development, while physiological development is largely coincidental[7,19]. gamebased training, on the other hand, simulates match conditions more closely and allows for significant physiological development.[7,12] conclusion time-motion analysis allows for the quantification of the physical and physiological demands of a cricket training session and the odg for the various sub-disciplines. the findings of this study highlight the distinctive physical and physiological demands placed on players in the different subdisciplines during training and an odg. the current study found that the major disparity between training and an odg was amongst the batsmen. this is valuable information for conditioning coaches in their development of sub-discipline and match-format specific training programmes. cricket training is generally skills and activity-based (batting, bowling, original research sajsm vol. 30 no. 1 2018 6 wicket keeping and fielding) and seldom replicates the game situation. it is recommended that game-based training should form part of the training regimes of teams. the results of the current study adds to the 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[pmid:19565683] 16. duffield r, drinkwater ej. time-motion analysis of test and one-day international cricket centuries, j sports sci 2008;26(5):457-464. [doi:10.1080/02640410701644026] 17. mcnamara dj, gabbett tj, naughton g, et al. training and competition workloads and fatigue responses of elite junior cricket players. int j sports physiol perform 2013;8(5):517-526. [doi: 10.1123/ijspp.8.5.517] 18. rampinini e, alberti g, fiorenza m, et al. accuracy of gps devices for measuring high-intensity running in field-based team sports. int j sports med 2015;36(1):49-53. [doi: 10.1055/s0034-1385866] 19. vickery w, dascombe b, duffield r, et al. battlezone an examination of the physiological responses, movement demands and reproducibility of small-sided cricket games. j sports sci 2013;31(1):77-86. [doi: 10.1080/02640414.2012.720706] https://doi.org/10.1080/026404100446739 javascript:void(0); javascript:void(0); javascript:void(0); https://doi.org/%2010.1016/%20j.jsams.2010.01.005 https://doi.org/10.1123/ijspp.6.3.295 https://doi.org/10.1123/ijspp.6.3.295 https://doi.org/10.1016/%20j.jsams.2006.01.003 http://dx.doi.or/10.1260/1747.9541.%208.3.531 https://doi.org/10.1177%2f1747954117731051 http://dx.doi.org/10.1123/ijspp.2016-0169 https://doi.org/10.1016/j.jsams.2013.10.224 https://doi.org/10.1123/ijspp.8.5.517 https://www.ncbi.nlm.nih.gov/pubmed/25254901 https://www.ncbi.nlm.nih.gov/pubmed/?term=vickery%20w%5bauthor%5d&cauthor=true&cauthor_uid=22963389 https://www.ncbi.nlm.nih.gov/pubmed/?term=dascombe%20b%5bauthor%5d&cauthor=true&cauthor_uid=22963389 https://www.ncbi.nlm.nih.gov/pubmed/?term=duffield%20r%5bauthor%5d&cauthor=true&cauthor_uid=22963389 https://www.ncbi.nlm.nih.gov/pubmed/22963389 https://www.ncbi.nlm.nih.gov/pubmed/22963389 editorial 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license south african journal of sports medicine: 2020 what lies ahead? the start of 2020 provides an opportunity to reflect on 2019 to determine how the south african journal of sports medicine developed. this should be aligned to the journal’s goal to promote research associated with sport and exercise medicine, in particular, research which addresses questions relevant to sport, exercise, nutrition and health in south africa. in 2019, the journal published eight original research papers, two commentaries, one invited review, one case study, two reports and two conference proceedings. although the number of outputs is relatively low, on closer inspection, the majority of outputs have direct relevance to the journal’s target audience in south africa. a journal has to continually find the balance between outputs which are relevant to the target audience and ensuring that these papers are of a high standard. this is a difficult balance to achieve because most authors with high quality work, even with a local relevance, will try and get their work published in high impact international journals. while the south african journal of sports medicine could publish lower quality research papers to keep the number of outputs high, we believe this is not the correct decision. instead our strategic decision is to maintain the quality of the outputs at the expense of quantity. less than 50% of the papers submitted for review are accepted. this means that the journal’s growth, defined by the quantity of outputs, will be slower than desired. growth defined by output quality is more likely to place the south african journal of sports medicine on the trajectory that will result in it getting international scientific indexing (isi) accreditation sooner. this is the desired long-term goal which will enable the journal to become more dominant in this subject field, thereby attracting a greater number of good quality papers. the south african journal of sports medicine is already accredited by south africa’s department of higher education and training which enables researchers at south african institutions to get a research subsidy following publication in the journal. the papers published in the journal are also listed by several electronic databases, a full listing of which can be found on our website. the quality of any journal depends on the quality of the reviewers. in most cases, the reviewers have done their job well and provided good quality, thoughtful reviews. this not only assists the authors of the paper to improve their publications, but also raises the standard of the journal. the work by the reviewers is done anonymously and without pay. for this they are thanked in writing by the journal. we have to compete with other journals for reviewers. a midto high-tier quality scientist may receive several requests a week to review papers from other journals, so we appreciate the reviewers who agree to assist us. we are planning to have a training workshop during the year to train aspiring reviewers and sharpen the skills of those reviewers who have already some experience. the field of exercise and sports medicine continues to evolve. sometimes the questions with regard to the topics of the subject field are answered and at times the topic loses relevance. concussion during sport is an area within sports medicine which has attracted scientists from different disciplines. later this year the 6th international conference on concussion in sport will be held in paris. this is a prestigious conference which defines the current knowledge on sportsrelated concussion and research for the future. the conference on sports-related concussion started in 2001 and meets every four years. it is supported by the following: international olympic committee, fédération internationale de football association (fifa), international federation for equestrian sports, world rugby and the international ice hockey federation. the sport concussion assessment tool (scat) was developed from the conference held in 2005. this tool has become entrenched in sports medicine and is used around the world in a variety of sports. the tool has undergone several revisions to make it a valid and reliable tool and is likely to be tweaked further at this conference. a scientific committee coordinates the programme to ensure the knowledge in the area advances. the expert panel at the conference will develop a further consensus statement on concussion in sport, building on the previous consensus statements which have been published after each conference. [1,2] this document will define the management of athletes following a head injury during sport, using the most up-to-date evidence. the progress the scientists participating in the concussion movement have made shows how a focused, well-directed approach can transform concussion knowledge and, in particular, the management of athletes following a head injury. this is a good model for scientists working in other focused areas. mike lambert editor-in-chief s afr j sports med 2020;32:1. doi: 10.17159/2078-516x/2020/v32i1a7909 references 1. mccrory p, meeuwisse wh, aubry m, et al. consensus statement on concussion in sport: the 4th international conference on concussion in sport held in zurich, november 2012. br j sports med 2013; 47(5): 250–258. [http://doi.org/10.1136/bjsports-2013-092313] 2. mccrory p, meeuwisse w, dvorak j, et al. consensus statement on concussion in sport—the 5th international conference on concussion in sport held in berlin, october 2016. br j sports med 2017; 51(11): 838–847 [http://doi.org/10.1097/00001199199804000-00008] https://journals.assaf.org.za/index.php/sajsm/about http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7909 http://doi.org/10.1097/00001199-199804000-00008 http://doi.org/10.1097/00001199-199804000-00008 https://orcid.org/0000-0001-8979-1504 original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license south african professional super rugby players’ lived experiences of career-related traumatic injuries: a descriptive phenomenological analysis t m hall,1 ma; p j basson,2 phd; j s patricios,3 mbbch ffsem (uk) 1 counselling psychologist, private practice, sea point, western cape, south africa 2 counselling psychologist, lecturer, department of psychology, university of johannesburg, auckland park, johannesburg 3 sport and exercise medicine physician, wits sport and health (wish), faculty of health sciences, university of the witwatersrand, johannesburg corresponding author: t m hall (psychology@trevorhall.co.za) in many instances, professional sport is a lucrative livelihood in which athletes are paid commercially competitive salaries. injuries are costly financially and personally to competitors and their employers, and may impact career longevity. this is particularly relevant to professional sports, such as rugby union (rugby), that require a significant level of physical contact and in which a relatively high number of injuries occur. for example, schwellnus et al.[1] suggested that per season, 55% of super rugby players experience injuries that require more than one week of rest and rehabilitation before they re-enter competition. hence, evidence-based biopsychosocial injury information that can inform effective recovery protocols is sought after within the rugby environment. professional rugby players can be affected physically, psychologically and financially by severe rugby injury (sri).[2] sri is defined by fuller et al.[3] in their consensus statement on injury definitions in rugby union as a career-related injury that requires more than 28 days’ physical recovery.[3] although, historically speaking, research around the effects of sri revolved around physical aspects,[2] a description of the psychological components of rugby career-related stressors have also evolved. for example, nicholls et al.[6] reported that injury risk was the main stressor experienced by professional heineken cup rugby players during the 2004 season. more recently, studies aimed at understanding psychosocial sequelae associated with sri have emerged,[4,5] indicating that these issues can negatively affect both effective physical recovery and playing form.[2,4] arvinen-barrow et al.[2] found that the majority of professional rugby players will experience at least one sri during their careers, and that it is considered a significant stressor. according to these authors, as well as more recent researchers,[7] sri includes negative psychosocial concomitants that can affect the individual across multiple facets of their lifeworld. additionally, the results of research aimed at understanding the negative psychosocial consequences of sri allude to a variety of biopsychosocial experiences that can be considered as traumatic, including the oftentimes stage-wise progression of the traumatic experience.[8] the recognition of an sri experience as being traumatic could assist in the development of integrated, evidence-based and effective sri recovery protocols. a traumatic event includes the ‘exposure to actual or threatened death, serious injury, or sexual violence’.[9] the effect of a traumatic event may incorporate psychological ramifications, such as a sudden sense of helplessness or the loss of control of one’s ability to feel safe or secure within one’s own body and/or the outside world.[10] psychologically, trauma can be viewed as a situation or an event that shatters a person’s basic assumptions about themselves and the world they live in.[11] for the purposes of this research, an sri is considered as a traumatic event, which has threatened the anatomical integrity of a competitor. therefore, a traumatic rugby injury (tri) is an sri that consists of its related physical, psychological, social, financial, and career-impacting background: historically, non-career-ending traumatic rugby injury (tri) has been viewed from a predominantly biological perspective. however, dimensional perspectives, such as the biopsychosocial model, have highlighted the need to incorporate psychosocial understandings of tri into treatment plans. aim: to describe the lived experiences of a cohort of traumatically injured south african super rugby players in order to add to the body of literature on the subject of tri experience. methods: the employment of a qualitative, descriptive phenomenological method was used to achieve the research outcome. discussion: common descriptive themes indicated that tri seems to exist within three stages: the initial, emotional and subsequent reactions to the traumatic injury. sub-themes described within each stage included attempts at remaining positive and appraising the severity of the injury during onset, fear responses and concomitant feelings of loss related to foregone career opportunities during the emotional reactions stage, the employment of coping mechanisms, and relying on specific support structures during subsequent reactions. two novel experiences revealed within this study and not reported in the international literature included the injured players’ reliance on compartmentalisation and positive religious belief structures as coping strategies. all themes were reduced to descriptive phenomenological essences that describe a lifeworld or biopsychosocial experience of tri. conclusion: themes drawn from this study can be applied in the future design and implementation of expanded studies and psychological interventions aimed at assisting traumatically injured rugby players during their recovery process. the identified themes affirm aspects from the international literature while highlighting some uniquely south african outcomes. keywords: trauma, severe injury, descriptive phenomenology, psychology s afr j sports med 2020;32:1-6. doi: 10.17159/2078-516x/2020/v32i1a8622 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8622 https://orcid.org/0000-0002-4547-2971 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0001-7291-0298 original research sajsm vol. 32 no. 1 2020 2 consequences.[3,10] research focused on understanding negative psychosocial experiences related to traumatic sports injuries, including sris, has begun to emerge primarily outside of south africa.[4,5,12,13] studies aimed at understanding the psychosocial consequences of traumatic injuries sustained by athletes have revealed various stages of progression experiences, including an information processing stage, an emotional upheaval stage, and a positive outlook stage of severe injury.[12] traumatic rugby injury experiences a review of the literature from australia and the united kingdom revealed certain negative psychosocial factors experienced by traumatically injured professional rugby players. these include negative opinions of the team environment, increased perceptions of pain, frustration, loss of identity within the team, pressure to play while still being injured, and guilt regarding not being able to contribute to the team.[14] self-doubt and stress (career, medical, financial and social) were suggested as factors associated with tri by arvinen-barrow et al.[2] evans et al.[5] outlined perceptions related to the following associated with tri: 1. a loss of independence 2. increased levels of negative social comparison, 3. unwanted attention, loss of routine, 4. feelings of isolation and boredom, 5. anxiety related to incapacitation, 6. medical diagnostic uncertainty and injury prognosis, 7. disruptions in self-image, fears around weight loss, 8. concerns regarding the risk of re-injury, 9. missed competition opportunities, 10. external and internal pressures to recover 11. future performance anxiety the stigma related to negative perceptions of psychological support regarding both team coaches and administration were factors highlighted by green et al.[15] finally, carson and polman[4] mentioned that professional rugby players who have experienced a tri tend to employ a variety of cognitive coping strategies, specifically cognitive avoidance and blocking during tri recovery. outlined psychosocial consequences of career-related tri, as well as the documented stage-wise progression of the athlete’s injury experience, have been described outside of south africa. the aim of this research was to define the lived experiences of traumatically injured south african super rugby players. methods study design to achieve the aims of this study, the selected qualitative research lens was descriptive phenomenology. descriptive phenomenology aims to provide comprehensive information around specific lived experiences and reduce that information to a description of its essence.[16] a phenomenological essence is what would be uncovered if all layers of description are stripped away and the phenomenon under investigation reveals itself as it would if it could.[16] the phenomenon under investigation in this study is the experience of tri. specific participant biographical and injury information can be relevant in an interpretation of the descriptive themes generated from the research. however, this information is not specifically pertinent to the descriptive phenomenological method. simply put, descriptive essences of professional, career-related tri exist within the experience of the phenomenon regardless of specific pre-existing injury information finally, although qualitative phenomenological findings are not universally generalisable beyond the research sample, significant essences that are revealed are seen as indications of shared human experiences of the phenomenon under investigation.[16] participants three research participants were selected for this descriptive analysis via purposive sampling. the sample size was in accordance with giorgi’s[17] methodological recommendations. participants were south african professional super rugby players contracted by the same franchise to participate in the 2016 super rugby competition and listed as a, b, and c. all three participants were between the ages of 24 and 30 years old, considered old enough to be established within the profession but young enough to expect to continue to play after tri recovery. all three participants were recovering from a tri, as defined by fuller et al.[3] and had undergone surgery as part of their recovery protocol. differences in tri which included type, timing, prognosis and number of previous injuries could have affected the participant-specific findings of this study. however, as this phenomenological study aimed to extract descriptive universal essences of the phenomenon of careerrelated tri (i.e. essences of tri) specific participant injury information was not relevant to this aim. the descriptive phenomenological method relies on the participants’ ability to articulate their experiences of the phenomenon. all participants could adequately communicate in the english language, the first language of the researcher. recruitment ethical clearance to conduct this study was obtained from the university of johannesburg’s human research ethics committee. a professional franchise was approached via the team’s sports physician in order to assist in the recruitment of the research participants. an invitation letter to participate in this research was sent to each potential participant. information covering the objectives of the study, the interview process, and any potential negative outcomes were provided. each participant gave their written informed consent. data collection data were collected via three open-ended interviews that were conducted in a conversational (informal) style. the open-ended interview technique involves the interviewer posing a broad, non-descriptive and non-definitive question regarding the original research 3 sajsm vol. 32 no. 1 2020 phenomenon under review.[16] the same open-ended question posed to each study participant was, ‘please could you describe what you are experiencing as a result of your injury?’. all three interviews were recorded on an audio recorder. the recordings were then transcribed verbatim. descriptive phenomenological analysis descriptive phenomenological research requires that all researcher preconceptions be suspended or bracketed, as they may contaminate interpretations of the participants’ interviews. giorgi’s[17] steps for descriptive phenomenological analysis were employed in the analysis of the transcribed interviews. these steps consisted of the following. 1) each transcribed interview was read as a whole in order to gain a global, holistic understanding of the data.[17] 2) a second reading of the description was undertaken, while experiences of meaning transitions were noted (still in the words of each participant) in order to reduce the descriptions into meaning units. 3) the researcher then transformed the meaning units into descriptions that contained explicit psychological information of importance and value connected to the phenomenon under investigation.[17] 4) the psychological descriptions of the phenomenon under review were reduced further by re-examining and re-organising them in order to come to a synthesis of psychologically-based meaning units.[17] 5) appropriate descriptions of individual experiences were compared and integrated across participants in order to elicit potential commonalities and arrive at a description of general experiences. 6) themes common to at least two of the three interviewees were re-examined, re-organised, and synthesised into overarching descriptive universal essences found in the participants’ experiences.[17] discussion three general experiences of career-related tri comprised of initial, emotional, and subsequent reactions to the traumatic injury were revealed. these findings were described as a stagewise progression of tri experience. findings were aligned with previously described stages of athletic injury rehabilitation, such as 1) the information processing stage, 2) the emotional upheaval stage, and 3) the positive outlook stage.[12] initial reactions to the traumatic injury comprised the participants’ attempts at positivity and their cognitive appraisals of the injury’s severity. emotional reactions to the traumatic injury included participants’ descriptions of confusion around diagnoses, fear reactions (such as fear of surgical procedures and fear of financial losses), and feelings of loss (such as loss of career opportunities, physical fitness, and team connection). finally, subsequent reactions to the traumatic injury involved participants describing their awareness and implementation of adaptive coping mechanisms, including goal directedness, adaptive avoidance, compartmentalisation, visualisations, positive religious belief structures, and the reliance on insider, outsider, and medical team support structures. although three distinct stages of tri experience were described in this text, one could reasonably argue that emotional components exist across all three stages of experience. this aligns with the biopsychosocial model of understanding. however, the initial reactions to tri, as well as the subsequent reactions, were described in terms of purposeful attempts to control experiences rather than spontaneous emotional experiences. initial reactions to the traumatic injury attempts at positivity all participants described a degree of positivity in reaction to the shock of the onset of their injury. mention was made of consciously employing positivity as an initial reaction in order to defend against future-orientated fears. one participant described positivity as having arisen due to his lack of injury experience, his trust in the medical team, and the positive responses of his team mates. a lot of guys have … ops [surgery] done … and all of them, like everyone, is positive …’… you going to be alright, don’t stress, you’re going to do this and this with, doc … you’ll start your rehab in so many weeks and whatever’ this affirms the observation of kruger et al.[18] who noted positivity, together with cognitive self-appraisals, as one of the possible psychological skills that south african rugby players competing at transnational levels appear to have at their disposal. cognitive appraisals of injury severity each participant described the attempts made to assess the severity of their injuries. one participant indicated that he tried to rationalise his injury as part of his endeavours to assess the severity thereof. … there wasn’t a lot of emotion [during his reactions to the traumatic injury] but a lot of trying to rationalise things … i told myself, ‘you know what? it’s [traumatic sri] already happened, where to from here?’… and then … my mind was starting to think like, ‘… sherbet [expression of frustration], i hope this [sri] isn’t bad. i can feel it’. concannon and pringle[12] found in their study that during the initial or information processing stage of the injury, athletes may engage in self-reflection as a way of processing information around the injury, including the extent of physical damage done and the likelihood of returning to competition. emotional reactions to the traumatic injury diagnostic confusion all three participants described an experience of feeling confused related to either misdiagnoses or miscommunication around the original diagnosis. this feeling led to participants describing varying degrees of emotional destabilisation ranging from feeling disappointed to feeling angry. … and all of them [doctors across provincial and national teams] have different opinions of when i’ll be ready, or what was wrong initially, or what is wrong now … it’s challenging having a lot of people speak into your life at the same time about one thing but saying different original research sajsm vol. 32 no. 1 2020 4 things. the experience of confusion and its concomitant challenges has been documented by evans et al.[5] in their research aimed at understanding stressors experienced by injured athletes. these authors suggested that injured athletes experience stress and worry related to confusing injury diagnostic information. fear reactions participants described various fear reactions in response to their traumatic sri which was similar to that found in the literature related to injured elite athletes across several sporting codes.[13] fear around a surgical procedure participants described experiencing fear around the need for a surgical procedure. one individual expressed feeling ‘nervous’ prior to undergoing an exploratory operation. look, going into the [surgical] operation, i was still nervous. fear of financial loss participants expressed fear regarding the potential financial losses due to their tris. one participant mentioned that the potential loss of a future contract would place him in a difficult financial situation. what’s going to happen to my finances? … i think that might be where the fear is coming from … if that contract is taken away from you [me] or you [i’m] not able to play rugby in the next year … i think that’s where the fear would probably creep in. both evans et al.[5] and arvinen-barrow et al.[2] suggested that injured professional rugby players’ feelings of stress often include their perceptions of not being able to cope with financial demands placed on them. feelings of loss interviewees described painful emotional reactions to the realisation of what they had lost in terms of ‘near future’ career opportunities. one such reaction included the following: i had aspirations to play on the end of year tour, last year … and then this was like my goal for the year (crying). ja, (sigh) … i got the opportunity and everything and … missed it this year. i feel like it’s not that i let the opportunity go or whatever but i felt like the opportunity is gone. evans et al.[5] suggested that injured professional rugby players experience stress associated with their realisation of missed career opportunities across the injury onset and the rehabilitation stages of the injury process. subsequent reactions to the traumatic injury adaptive coping mechanisms all three participants described the employment of adaptive coping mechanisms during this stage of their injury trajectory. coping mechanisms that were mentioned by the participants included goal directedness, adaptive avoidance, compartmentalisation, visualisations, and using positive religious belief structures. carson and polman[19] mentioned that elite professional rugby players tend knowingly to employ coping strategies, mechanisms and skills, aimed at managing stressful demands including traumatic injuries. goal directedness participants described directing their consciousness towards using specific recovery and rehabilitation goals, as well as general career goals. one participant mentioned directing his attention to his goal of returning to play rugby, while activities not aligned to that goal were set aside. … you just keep going and the main goal [playing rugby again] remains the main goal … anything that’s not preferable [aligned to recovery] can wait. everything should be focused on me getting back [to competitive play]. carson and polman[4] suggested that effective goal-setting strategies seemed to assist injured professional rugby players in their attempts to return to competitive play. adaptive avoidance interviewees described intentionally avoiding those individuals or groups they thought would distract them from their recovery goals. mention was made of managing fears related to being negatively influenced by family members by avoiding them until a later stage of recovery. … they [his family] might pull my energy in a different direction [from his goal of recovery] and i start to slack in terms of what i’ve set out to do for myself (sigh) … that’s a sacrifice i had to make. adaptive avoidance (including cognitive avoidance and blocking) has been described in the literature by authors such as carson and polman[4] as one such coping mechanism employed by professional rugby players. compartmentalisation participants described compartmentalising their daily activities during their recovery. they mentioned how the separation of rugby and rehabilitation tasks from other life interests assisted them in coping with their sri recovery. rugby is not my life, it’s part of my life … i can go home to my family and, consciously, i disconnect from being a professional rugby player … i’m a father and a husband and through that, through that disconnection, i have peace. specific literature pertaining to the employment of compartmentalisation as a coping mechanism by injured sports people was not found. this finding could also suggest a novel and south african component of tri recovery. visualisations participants mentioned the use of positive visualisation original research 5 sajsm vol. 32 no. 1 2020 techniques to control their thoughts and emotions during their recovery processes. one individual described how visualisation techniques ‘triggered’ him into remaining motivated to play rugby again. i believe that visualising playing in that jersey [team rugby jersey] again really helps me … it’s almost like a trigger to see it [playing again] … it’s easy to say its motivation. it is to an extent but it triggers my mind. carson and polman[19] maintained that use of imagery as a coping strategy has proved to be beneficial in injured rugby players’ recovery processes. positive religious belief structures a reliance on religious belief structures in order to cope with a traumatic rugby injury was described by two participants. one participant mentioned how his practices of faith and prayer assisted him in his belief that he would be able to control the outcomes of his recovery process. i’d go to church and the people would pray for me and it will be the same thing, just speak it [positive recovery] into existence and now i’m sitting here and i’m thinking, ‘flip [colloquial expression used in this case as surprise], i could be back [playing rugby] in six months (laughing)’. no existing literature pertaining to the employment of positive religious belief structures as a coping mechanism regarding injured athletes or rugby players was found. hence, this coping mechanism could be considered a south african component of psychosocial tri recovery, especially if replicated in additional studies across similar contexts. support structures participants described their awareness of how certain support structures, including both insider, outsider, and medical team support, positively assisted them during their respective rehabilitation. williams and appaneal[13] suggested that injured athletes are often influenced, either negatively or positively, by their support structures and that those injured athletes who perceive a lack of social support might experience negative cognitive perceptions in their self-worth and self-confidence. insider support all participants described support received from teammates as being beneficial. one individual communicated how he felt supported by other injured teammates. … having guys that are also injured with you [me] … they also have niggles, they also come there, with doc [biokineticist] and [we] do our stuff together. even though we’re doing completely different things, it’s just lekker [slang expression for ‘pleasant’] having guys that [who] are in a similar scenario as you [me] … having them around was nice. carson and polman[19] suggested that injured professional rugby union players might become motivated to recover via the exposure to positive team support structures. outsider support outsider support was described by interviewees as being helpful to them during their convalescence. one interviewee mentioned his girlfriend as being particularly supportive of him at both physical and emotional levels. my [girlfriend] was also very supportive … i think she wants to try help. she did help me a lot … also, [i] not knowing what to expect [from the surgical procedure], neither did she. williams and appaneal[13] suggested that the availability of social support in the form of relationships both with teammates and family is vital regarding the ability of injured athletes’ to protect themselves from feelings of neglect and abandonment. medical team support participants described themselves as reacting positively to the support that they received from their medical team during the rehabilitation stages of their injury. one participant mentioned the following: he [the biokineticist] just answered all my questions … he’ll be [he was] straight with me … he’ll say my external rotation is looking good [or] he tells me, ‘okay, that’s not good, we can work on that’ … he [the biokineticist] was also just honest with me. he didn’t sugar coat anything. in their 2017 study, carson and polman[4] proposed that an injured professional rugby player’s recovery seemed to be assisted by the support received from the medical team treating him. universal essences common phenomenological essences were divulged by all three participants which included the following: being confronted with both physical and psychological limitations, while intentionally attempting to make meaning out of the tri experience and the recovery process. all three participants attempted to create meaning during their recovery process via the intentional recognition of their physical injury, the experience of emotional reactions, and the deliberate and directional implementation of coping strategies which included the seeking out of social support. limitations as with most qualitative research, results should not be generalised across all rugby playing populations due to small sample sizes, such as in this research study. furthermore, the descriptive phenomenological method does not aim to interpret findings. hence, enquiries regarding how or why descriptions of the tri experience exist were limited in this research. conclusion the occurrence of tri within a sample of professional south african super rugby players revealed a stagewise biopsychosocial experience. this experience was reduced to universal essences, which included a reliance on and original research sajsm vol. 32 no. 1 2020 6 confrontation with both physical and psychological limitations, while intentionally striving towards establishing their significance. as previously discussed, no traumatic event occurs entirely from the physical, psychological, or social point of view. rather, there is an interaction between the three components of the experience. according to this research, there appear to be additional factors unique to the south african experience of tri. the two descriptive phenomenological themes in this study and not found in the international literature are coping strategies of compartmentalisation and the reliance on positive religious belief structures. the fact that two themes, possibly unique to the south african super rugby population, were extracted from this study adds credibility to the idea that the experience of career-related tri is embedded in the biopsychosocial lifeworld of the participant. further investigations regarding how unique experiences of tri can affect recovery protocols across different and larger cohorts will add further value to the subject. furthermore, quantitative studies aimed at understanding what specific experiences positively or negatively influence recovery protocols could assist in the development of specific but malleable psychosocial interventions aimed at tri recovery. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: th: lead author, conception, design, analysis and interpretation. pb: supervisor, co-conception, design and editing. jp: critical revision and editing. references 1. schwellnus mp, thomson a, derman w, et al. more than 50% of players sustained a time-loss injury (>1 day of lost training or playing time) during the 2012 super rugby union tournament: a prospective cohort study of 17 340 playerhours. br j sports med 2014;48(17):1306-1315. [doi:10.1136/bjsports-2014-093745][pmid: 24982503] 2. arvinen-barrow m, massey wv, hemmings b. role of sport medicine professionals in addressing psychosocial aspects of sport-injury rehabilitation: professional athletes’ views. j athl train 2014;49(6):764-772. [doi:10.4085/1062-605049.3.44][pmid: 25243737] 3. fuller cw, molloy mg, bagate c, et al. consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union. br j sports med 2007;41(5): 328-331 [doi:10.1136/bjsm.2006.033282][pmid: 1742684] 4. carson f, polman rc. self-determined motivation in rehabilitating professional rugby union players. bmc sports sci med rehabil 2017;9(2). [doi:10.1186/s13102-016-00656][pmid: 28116102] 5. evans l, wadey r, hanton s, et al. stressors experienced by injured athletes. j sports sci 2012;30(9): 917-927. [doi:10.1080/02640414.2012.682078][pmid: 22551525] 6. nicholls ar, holt nl, polman rc, et al. stressors, coping, and coping effectiveness among professional rugby union players. sport psychol 2006;20(3): 314-329. [doi: 10.1123/tsp.20.3.314] 7. hurley oa. impact of player injuries on teams' mental states, and subsequent performances, at the rugby world cup 2015. front psychol 2016;7:807. [doi:10.3389/fpsyg.2016.00807] [pmid: 27375511] 8. eagle g. an integrative model for brief term intervention in the treatment of psychological trauma. int j psycother 1998;3(2):135-146. available from [https://search.proquest.com/openview/a23dfb9c1b6943289b2 eb95a4bdb3b80/1?pq-origsite=gscholar&cbl=32791] 9. american psychiatric association. diagnostic and statistical manual of mental disorders. s.l.: american psychiatric publishing. 5th ed., 2013. p 271. 10. corbett l, milton m. existential therapy: a useful approach to trauma? couns psychol rev 2011;26(1): 62-74. retrieved from: https://psycnet.apa.org/record/2011-06757-006. 11. janoff-bulman r. assumptive worlds and the stress of traumatic events: applications of the schema construct. soc cogn 1989;7(2):113-136. [doi: 10.1521/soco.1989.7.2.113] 12. concannon m, pringle b. psychology in sports injury rehabilitation. br j nurs 2012;21(8): 484-490. [doi:10.12968/bjon.2012.21.8.484][pmid: 22585077] 13. williams ra, appaneal rn. social support and sport injury. int j athl ther train 2010;15(4): 46-49. [doi: 10.1123/att.15.4.46] 14. cresswell sl, eklund rc. the nature of player burnout in rugby: key characteristics and attributions. j appl sport psychol 2006;18(3): 219-239. [doi:10.1080/10413200600830299] 15. green m, morgan g, manley aj. elite rugby league players’ attitudes towards sport psychology consulting. sepr 2012;8(1); 32-45. [doi: 10.1037/spy0000103] 16. lindegger g. research methods in clinical research. in: terre blanche m, durrheim, k, painter d. research in practice: applied methods for the social sciences. 2nd rev. ed. cape town: uct press; 2006: 455-475. 17. giorgi a. the descriptive phenomenological psychological method. j phenomenol psychol 2012;43(1): 3-12. [doi:10.1163/156916212x632934] 18. kruger p, potgieter j, malan d, et al. prior experience, cognitive perceptions and psychosocial skills of senior south african rugby players. s afr j res sport phys educ 2010;32(1): 69-84. [doi: 10.4314/sajrs.v32i1.54101] 19. carson f, polman rc. the facilitative nature of avoidance coping within sports injury rehabilitation. scand j med sci sports 2010;20(2): 235-240. [doi:10.1111/j.16000838.2009.00890.x][pmid: 19422659] https://doi.org/10.1080/02640414.2012.682078 doi:%2010.1521/soco.1989.7.2.113 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%20%5bdoi sajsm 595 (commentarty).indd commentary 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license ‘make exercise the elixir across an economic divide’: a message to covid-19 decision makers j patricios, 1 mbbch, ffsem (uk); r saggers, 1, 2 mbbch, fc paed (sa); b gelbart, 1, 3 mbbch fcs (ortho), mmed (ortho); j van zuydam, 1 mbbch msc (sports med) 1 wits institute for sport and health (wish), school of therapeutic medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 2 department of paediatrics, school of clinical medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa 3 department of orthopaedics, school of clinical medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: j patricios (jonathan.patricios@wits.ac.za) south africa’s lauded response to the global pandemic was initiated publicly by the launch of its hotline to the national institute of communicable disease (nicd) on 14th february 2020, followed by its first recorded case of covid-19 on the 5th march 2020.[1] discussion demographic and health challenges the country has a demographically heterogeneous population but also a large disparity in resource distribution with a gini coefficient of 63.[2] while some members of the population live in first world conditions with spacious dwellings, private medical insurance and access to a range of technologies, the majority live in informal settlements, which are densely populated, making the spread of infectious disease more probable and physical distancing challenging. moreover, south africa has an hiv prevalence of 20.4% (7.7m people) [3] and approximately 530 000 tuberculosis cases.[4] significantly, rates of obesity and metabolic syndrome are also alarmingly high across both cohorts. [5] lifestyle diseases the published data show that pre-existing conditions, such as obesity, diabetes, hypertension and chronic cardiovascular disease, significantly increase mortality in covid-19 patients. [6,7] just as intensivists know which pre-existing ailments raise a red flag for the covid-19 patient, sport and exercise medicine clinicians appreciate how regular exercise is a most effective intervention across the spectrum of these comorbidities. pandemic predictions initial predictions indicated a potential positive number of south african covid-19 cases in excess of 12 million by 10 april 2020 [8], with a 15% incidence of severe disease and a mortality rate of 2%.[9] a significantly lower disease incidence trajectory was achieved by a 5-week hard lockdown that allowed for only essential services to be open and during which exercise outside of homes was prohibited. not only did economic productivity inevitably decline but so too did levels of physical activity. exercise as the ultimate immune booster the virtues of regular exercise, namely physical, cognitive, and social, have been validated and extolled repeatedly. together with sound nutrition, its role in controlling the metabolic syndrome is critical. less well publicised is the impactful role of exercise on the immune system. acute exercise stimulates the interchange of innate immune system cells between lymphoid tissues and the bloodstream. [10] over time, a summation effect occurs resulting in improved immunosurveillance against pathogens and decreased systemic inflammation. [11] randomised clinical trials have shown how near-daily moderate activity decreases the incidence of upper respiratory tract infections by 40%-50% surpassing the efficacy of most drugs and supplements. [12] importantly, a recent systematic review of the immunology literature has shown that the most vulnerable patients with an adverse outcome after sars-cov-2 infection may benefit most from the immune-regulating effects of regular exercise.[11] these include obese, diabetic, hypertensive and cardiac patients. moreover, regular exercisers have a lower incidence and mortality for influenza and pneumonia. there is also an enhanced response to vaccinations, and immunosenesence (the immune dysregulation associated with aging) is delayed by habitual exercise. [11] exercise needs to be undertaken gradually by those who are unaccustomed to regular exercise and those who have taken a break from training. changes in training load should be in small increments, with data indicating that weekly increments should be <10%. [13, 14] when introduced responsibly, exercise is an immune booster par excellence with a particularly positive effect in those with comorbidities and in age groups commonly associated with poor outcomes to covid-19. exercise should be a key intervention rather than a prohibition in any national pandemic strategy. it is also freely available. exercise and risk mitigation south africa’s initial lockdown directive was to prohibit not only organised sport, but exercise outside of the home, the goal being to prevent the social interaction associated with sport. those with the self-discipline and the means (smartphones, south africa, like other countries around the world, has used a lockdown strategy to address the initial phases of the covid19 epidemic. the significant restrictions on population movement have included initially limiting exercise to the home. there is substantial evidence for the many benefits of exercise. this study specifically emphasises the benefits of exercise to the immune system, particularly for those most vulnerable to the effects of the sars-cov-2 virus and proposes measures to improve access to exercise in a demographically diverse and economically disparate society. keywords: coronavirus, immunity, exercise, metabolic syndrome s afr j sports med 2020; 32:1-2.doi: 10.17159/2078-516x/2020/v32i1a8310 mailto:jonathan.patricios@wits.ac.za http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8310 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0002-1776-1290 https://orcid.org/0000-0001-6593-8049 https://orcid.org/0000-0003-2024-0442 commentary sajsm vol. 32 no. 1 2020 2 wifi and space) were able to make use of a number of online resources, including personal trainers and ’zoom’ classes. a major health insurer (discovery) introduced the concept of a home workout channel, “vitality at home” [15], while a wits institute for sport and health collaboration has produced an online tool (available at https://www.insightfit.com/) to screen athletes for any symptoms of covid-19 before calculating an individualised safe return to training. but what options exist for those in informal dwellings in an over-populated settlement? the first relaxation of lockdown restricted exercise to walking, jogging and cycling for a window of three hours in the early morning within a five km radius of home whilst emphasising physical distancing instructions. this proved difficult as socially-starved active communities often turned out en masse counter to the intention, crowding popular public thoroughfares. an alternative strategy if acknowledgement that the immune-boosting benefits of exercise are substantial is given, these authors strongly suggest prioritising the optimisation of immune health during a viral pandemic where the body’s innate and adaptive immune responses are the ultimate defence against the microbe. a more sophisticated strategy is proposed that sees physical activity prioritised at every stage of risk mitigation against the disease. specifically:  ongoing hygiene measures handwashing, sanitiser use, respiratory etiquette and increased physical distancing (potentially greater than the two metres recommended for static distancing) during exercise remain non-negotiable. the use of masks and buffs when sharing any public space, including during exercise, seems a sensible (if not scientifically-proven) intervention  availing and martialling of public spaces to facilitate exercise with physical distancing under supervised conditions  allowing more extended periods of exercise outside of the home to diminish the number of people exercising at once  permitting participation in those sports that easily facilitate physical distancing, such as golf, singles tennis, surfing, swimming in open water or in large, chlorinated pools with lanes  providing specific guidelines to schools to encourage exercise on school grounds with the return to schools  proceeding with a phased introduction of individual and team sports in controlled environments until herd immunity is achieved or a vaccine becomes available. use the opportunity...and this medicine physical exercise is accessible across ages, economic strata and social divides. facilitating outdoor activity in the context of social lockdown may seem counter-intuitive. however, the overwhelming evidence for the benefits of regular physica l activity on the human immune system, as well its efficacy as an intervention in those most vulnerable, makes it imperative that exercise is prioritised at every level of lockdown risk stratification. a more nuanced and sophisticated strategy by governments will utilise the current trying global health crisis to highlight exercise as the preventative and interventional medicine that it is. conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: all authors contributed to the concept of the commentary and researched specific aspects. jp collated the data, drafted the text and refined the final submission. references 1. mkhize z. first case of covid-19 coronavirus reported in sa. johannesburg: national institute for communicable diseases, 5 march 2020. available from: https://www.nicd.ac.za/first-case-ofcovid-19-coronavirus-reported-in-sa/ (accessed 3 may 2020). 2. world bank.development research group. gini index (world bank estimate) south africa. washington: world bank group, 2019. available from: https://data.worldbank.org/indicator/si.pov.gini?locations=za (accessed 3 may 2020). 3. unaids. south africa . washington: unaids, 2020. available from: https://www.unaids.org/en/regionscountries/countries/ southafrica (accessed 3 may 2020). 4. naidoo p, theron g, rangaka mx, et al. the south african tuberculosis care cascade: estimated losses and methodological challenges. j infect dis 2017;216(supplˍ7):s702-713. [http://dx.doi.org/10.1093/infdis/jix335][pmid: 29117342] 5. shisana o, labadarios d, rehle t, et al. south african national health and nutrition examination survey (sanhanes-1). cape town: hsrc press, 2014: ch 3:72-133. 6. grasselli g, zangrillo a, zanella a, et al. baseline characteristics and outcomes of 1591 patients infected with sars-cov-2 admitted to icus of the lombardy region, italy. jama 2020;323(16):15741581. [http://dx.doi.org/10.1001/jama.2020.5394] [pmid: 32250385] 7. mehra mr, desai ss, kuy s, et al. cardiovascular disease, drug therapy, and mortality in covid-19. n engl j med 1 may 2020;18. [http://dx.doi.org/10.1056/nejmoa2007621] [pmid: 32356626] 8. kings s. 665 to 12-million infected: the possible sa coronavirus numbers. mail & guardian, 12 march 2020. available from: https://mg.co.za/article/2020-03-12-concern-that-hospitals-wontbe-able-to-cope-with-covid-19/ (accessed 6 may 2020). 9. wu z, mcgoogan jm. characteristics of and important lessons from the coronavirus disease 2019 (covid-19) outbreak in china: summary of a report of 72314 cases from the chinese center for disease control and prevention. jama 2020;323(13):1239-1242. [http://dx.doi.org/10.1001/jama.2020.2648] [pmid: 32091533] 10. adams gr, zaldivar fp, nance dm, et al. exercise and leukocyte interchange among central circulation, lung, spleen, and muscle. brain behav immun 2011;25(4):658–666. [https://doi.org/10.1016/j.bbi.2011.01.002] [pmid: 21238578] 11. nieman dc, wentz lm. the compelling link between physical activity and the body’s defense system. j sport health sci 2019;8(3):201-217. [https://doi.org/10.1016/j.jshs.2018.09.009] [pmid: 31193280] 12. nieman dc, nehlsen-cannarella sl, markoff pa, et al. the effects of moderate exercise training on natural killer cells and acute upper respiratory tract infections. int j sports med 1990;11(6):467– 473. [http://doi.org/10.1055/s-2007-1024839] [pmid: 2286486] 13. jones cm, griffiths pc, mellalieu sd. training load and fatigue marker associations with injury and illness: a systematic review of longitudinal studies. sports med 2017:47(5):943-974. [http://doi.org/10.1007/s40279-016-0619-5] [pmid: 27677917] 14. schwellnus m, soligard t, alonso jm, et al. how much is too much? (part 2) international olympic committee consensus statement on load in sport and risk of illness. br j sports med 2016;50(17):1043-1052. [doi.org/10.1136/bjsports-2016-096572] [pmid: 27535991] 15. discovery limited. vitality home-workout channel. johannesburg: discovery limited, 2020. available from: https://www.discovery.co.za/vitality/vitality-home-work-outchannel (accessed 6 may 2020). https://www.insightfit.com/ https://www.nicd.ac.za/first-case-of-covid-19-coronavirus-reported-in-sa/ https://www.nicd.ac.za/first-case-of-covid-19-coronavirus-reported-in-sa/ https://data.worldbank.org/indicator/si.pov.gini?locations=za https://www.unaids.org/en/regionscountries/countries/%20southafrica https://www.unaids.org/en/regionscountries/countries/%20southafrica https://www.ncbi.nlm.nih.gov/pubmed/32250385 https://mg.co.za/article/2020-03-12-concern-that-hospitals-wont-be-able-to-cope-with-covid-19/ https://mg.co.za/article/2020-03-12-concern-that-hospitals-wont-be-able-to-cope-with-covid-19/ https://www.discovery.co.za/vitality/vitality-home-work-out-channel https://www.discovery.co.za/vitality/vitality-home-work-out-channel introduction rugby is a full-contact sport which has one of the highest injury rates when compared with other team sports. 9 although injuries are expected from any high-speed and high-impact situation, steps have been taken to minimise the high injury rates within rugby. law changes, cutting down on foul play, improving protective equipment as well as increasing the emphasis on proper conditioning are but a few of the steps taken with the goal of reducing the risk of injury. due to the increase in injury risk a considerable amount of research has been conducted on the nature and cause of injuries in rugby, and how they can be prevented. nevertheless, there is a need for further examination of specific game events associated with higher injury rates. 9 although a significant amount of research is concerned with the risk of spinal injury associated with playing rugby, 17 further research is required around injuries to the lower back and core. background trends in the nature of injury in rugby have changed since 1995 as a result of numerous modifications to the laws combined with the creation of professionalism within the sport. 9 the changes since 1995 have been associated with some negative consequences such as an increase in injury risk for both professional and amateur games. 38 however, the financial rewards associated with professionalism can in some ways be linked to an increase in participation and hence an increase in the rugby player population. 6 the increase in the number of individuals playing rugby has therefore resulted in an increase in the population at risk of rugby-related injuries. the head, rib cage, pelvis, and spinal column form the central component of the skeleton. one of the primary functions of this central component is to absorb and dissipate forces which act upon the body; this role is mainly fulfilled by the spine and the muscles which support it. an increased possibility of injury occurs if there is a dysfunction in the protective and load-distributing capacity of the spine. this is particularly evident in the lumbar spine, which can be seen as the building block for the low back region. the low back is an integral part of the entire movement chain as it functions as part of commentary boksmart: preventive rehabilitation for rugby injuries to the lower back and core abstract background. the low back is an integral part of the entire movement chain as it functions as part of a complex network of the skeletal, muscular and nervous system. eighty to 90% of acute low back pain episodes dissipate within 8 12 weeks regardless of any intervention, but 5 10% regress into chronic low back pain. as a result of its undistinguished aetiology, the treatment for low back pain remains controversial. treatment options for low back pain include the following: analgesics, muscle relaxants, antidepressants, nonsteroidal anti-inflammatory drugs, epidural steroid injections, manipulation, back schools, electromyographic biofeedback, traction, orthoses, behaviour therapy, transcutaneous electrical nerve stimulation, acupuncture, and exercise therapy. results. therapeutic exercises for low back pain have been shown in 6 different randomised controlled trials to be beneficial in reducing pain by up to 60% and improving functional ability by up to 47%. furthermore, a cochrane review on low back pain found strong evidence that exercise therapy is an effective intervention in the treatment of low back pain. when prescribing exercises for an individual with low back pain the following goals need to be considered: (i) improve performance in endurance activities; (ii) improve muscular strength around the spine; (iii) eliminate any impairments in spinal flexibility; (iv) reduce the intensity of the pain being experienced by the individual; and (v) reduce back pain-related disability. a rugby player will have increased core stability/strength and a reduced risk of injury if the internal support mechanisms of the spine have been conditioned to resist distortion or injury from external forces. not only will improved core correspondence: neil hopkins murphy & hopkins biokineticists vincent pallotti hospital, rehabilitation and hydrotherapy centre dick williamson medical centre, lower ground level pinelands 7405 south africa tel.: +27 (21) 532 3203 e-mail: neilhopkins.sa@gmail.com neil hopkins (bsc(med) (hons) exercise science (biokinetics))1 wayne viljoen (phd)2 1 private biokineticist: murphy & hopkins biokineticists 2 manager: boksmart national rugby safety programme stability benefit players on the field during matches or practices, it will also assist in preventing unnecessary injuries during weight training and pre-season conditioning. conclusion. exercise programmes which combine core stability with general strength training should be prescribed for rugby players to prepare them for the level of impact involved in the game, as well as for sport-related weight training and non-sport-related daily activities. sajsm vol 20 no. 4 2008 95 a complex network of the skeletal, muscular and nervous systems. 40 countless research hours have been spent trying to determine the exact cause of low back pain, but numerous cases of low back pain remain unexplained as a result of the complex relationship between the brain, bones, muscles and ligaments. low back injuries are not a phenomenon exclusive to rugby players or any other athlete population; it is a global phenomenon. this is evident from the large number of low back-related disorders within normal populations. low back pain affects a large number of sedentary individuals and is the greatest cause of absence from work, or loss in work productivity. 47 in south africa, this is evident by the fact that physiotherapists treat at least 6 patients with low back pain per week, 47 with 60 80% of the population experiencing back pain at some time in their life. 46 in the majority of cases the mechanical cause of low back pain will differ between sedentary and athletic populations. normal populations tend to get lifestyleassociated back pain whereas rugby players tend to suffer from back pain which is associated with exercise, rather than the lack thereof. however, the structures affected in the low back are the same in both population groups, as their human anatomy does not differ. eighty to 90% of acute low back pain episodes dissipate within 8 12 weeks regardless of any intervention; 23 however, 5 10% regress into chronic low back pain. 31 used in this sense the term chronic does not refer to the intensity of the pain but rather to the extent of its duration. individuals who suffer from low back pain for longer than 12 weeks are considered to have chronic low back pain. 1 chronic low back pain appears to be caused by a multiple combination of risk factors which vary between individuals. 30 there is a vast amount of literature on low back pain, with over 5 000 published articles, 3 but there are very few studies conducted on chronic low back pain that are randomised or controlled. 22 a considerable amount of the available research has tried to establish whether any functional or anatomical differences exist between individuals who suffer from chronic low back pain and those who do not. 16 current research has also been aimed at determining whether low back pain is the result of suboptimal neuromuscular control under dynamic conditions. 41 the results of the research around the low back have been inconclusive, partly due to the fact that the spine and its associated structures are complex in nature and therefore difficult to study. 41 most common injuries injury to the spine in rugby occurs mainly to the cervical spine; however there is also a risk of injury to the low back and its supporting structures. 17 there are numerous mechanical forces involved in producing spinal injuries and the most common injuries to the spine occur as a result of one, or a number, of these forces acting on the lumbar spine or the surrounding tissue. 36 these forces can be broken down into: flexion forces (forward bending), extension forces (backward bending), rotation forces (twisting), shear forces (one vertebra sliding in relation to another), and compression forces (vertical pressure). 36 it is often the extremes of range or force that result in injury; however, even a relatively small force can result in an injury if the spine is not adequately supported. the most effective way to categorise sport-related injuries to the low back is to break them down into the structures affected. these include: fractures to the spinal column, injury to the interverterbral disk, ligament strain, joint inflammation, and muscular spasm. 10 other less common injuries also occur, which is why an accurate diagnosis is essential before treatment. mechanism of injury the research on the incidence of injury shows that the majority of injuries in rugby occur when tackling or being tackled. 9 tackles have been found to be the rugby event responsible for the greatest number of injuries as they are by far the most common contact event in the game. as a result they account for the greatest cause of all injuries, followed by the ruck/maul. 38 there are various types of tackles, each with their own risk for the player tackling and the player being tackled. dangerous tackles include blind tackles, gang (group) tackles, and spear tackles. blind tackles occur when the player is tackled from behind or from a position outside of their range of vision (in the player’s peripheral vision). 19 there is a higher risk of injury with this kind of tackle as the player is often caught unaware, and is often unprepared for the impact. the tackle with the greatest risk of spinal injury is the spear tackle, which has subsequently been banned from rugby as it constitutes foul play. 38 further studies have also shown that although tackles cause the greatest number of injuries it is collisions which are more likely to result in injury. 18 even though there are fewer collisions during a game, they are more likely to result in an injury than a tackle. 18 the forces involved in scrumming and the positioning of the players have always been a concern when it comes to spinal injuries. 37 however, thanks to a greater awareness of the dangers involved in scrumming, the risk of spinal injury in the scrum has decreased. 20 due to improvements in refereeing and laws governing the scrum, the number of injuries as a result of scrumming has decreased in comparison with the number of injuries sustained during the ruck and maul phases. 38 nevertheless scrums are inherently dangerous because the players are placed into positions that have the potential to compromise the safety of the spine. as a result, scrums carry a much greater risk of injury than tackles. 18 the forces involved in scrumming not only have the potential for severe spinal injuries but they place an increased amount of strain on the low back, especially on the discs between the lumbar vertebrae. the majority of research up until now has focused on the incidence of traumatic injuries to the spine, especially the cervical spine, but there is also a risk of non-traumatic, overuse injuries 17 . research has also indicated that not only do rugby players have a high risk of spinal injury from game-related activities, but as a result of weight-training activities as well. 17 there is no consensus on the most dangerous position in rugby, because certain positions carry different risks for different injuries. it is safe to assume that the positions that carry the greatest risk of injury are those involved with the most contact and the greatest number of tackles, such as the loose forwards and certain players in the backline. some players have a greater risk of injury to the low back as a result of game situations that are unique to their position. players who are involved in a greater number of contact situations will obviously have a greater risk, along with players in dangerous positions in the scrum, such as the front row. one study shows that with regards to low back injuries, hookers and flyhalves have the highest incidence of injuries, hookers and outside centres have the greatest risk of injury, while the greatest severity of injury was experienced by locks and flankers. 8 the injury rate to the low back is the same for forwards and backs; however, the majority of low back-related injuries for forwards occurred because of ruck and maul situations whereas backline players were mainly injured in tackle situations. 8 the severity, however, of low back injuries between forwards and backs differed. low back injuries in backline players, caused by excessive twisting and turning while tackling or being tackled, were more severe and resulted in more time off. 8 96 sajsm vol 20 no. 4 2008 the rate of injury in rugby has been found to be directly proportional to the level of the game but inversely proportional to the age of the player. 6 what this means is that more injuries occur in higher teams (1st team) and older age groups and fewer injuries occur in lower teams (5th team) and junior levels of rugby. it has also been found that rugby matches carry a far greater risk of injury than practices, especially matches played at the start of the season. 11 research has indicated that most injuries occur at the start of the season or during the first few weeks following a break mid-season. 43 a generally accepted principle in the discipline of sports medicine is that the greatest predictor of a future injury is a previous injury. 10 this is an important finding because the return to sport phase following an injury will carry a similar level of risk to the early phases of the rugby season. most injuries result in time off, with injuries caused by tackles resulting in the greatest amount of time off. 8 it is imperative that injured rugby players be fully recovered and conditioned before returning to game situations, in order to avoid further injury, further time off, and possibly a reduction in length of their rugby careers. 35 spinal stability stability of the lumbar spine requires passive stiffness through bone and ligament structures and active stiffness through muscle contraction. 40 the passive structures provide stability through their structural composition and hence cannot produce movement. passive structures such as ligaments are only effective at the end of range to prevent excessive segmental movement of the spine. 40 the active structures provide stability by contracting or tightening and play a predominant role in maintaining lumbar spine stability throughout the entire range of movement. 40 these active structures are made up primarily of muscles located around the lumbar spine, such as the transversus abdominus and multifidus. the abdominal muscles, which are fundamental to the active maintenance of spinal stability, include the internal oblique, external oblique, transversus abdominus, 5 and to some degree rectus abdominus. essentially spinal stability requires the contraction of key muscles, individually as well as in co-operation with each other, to maintain posture and intersegmental control. to visualise this intricate stabilising system, imagine the spine as a tent pole and the muscles as the supporting guy ropes. 2 if the tent pole is placed upright on the ground without any external support it will fall over. the role of the guy ropes is to provide support to the otherwise unstable tent pole. the more guy ropes the more stable the tent pole, just as without the guy ropes the tent pole will fall over. segmental stability between the vertebrae is primarily provided by local muscles which have influence over inter-segmental control due to their attachments on the lumbar spine. 7 behavioural evidence has shown that the transversus abdominus can be classified as one of these local muscles and therefore makes up an important part of the core-stabilising musculature. 24 transversus abdominus has an influence on segmental stability in a general manner, but this stability is not direction specific. 25 this implies that the transversus abdominus plays a role in multidirectional stability and thus protects the spine from forces acting in a multitude of directions. research has shown that transversus abdominus is the first muscle to activate prior to limb movement, but is delayed in individuals with low back pain. 27 the importance of activation prior to movement is that it generates spinal stiffness, and therefore prevents hypermobility. 27 the spinal stabilising system is made up of three subsystems. 40 the three subsystems are made up of the spinal column, which provides intrinsic stability, the muscles which provide dynamic stability, and the neural control unit, which functions to co-ordinate the muscular response. 40 this muscular subsystem has a significant role to play, as correct muscle activation is essential in the maintenance of posture and intersegmental control during movement. 27 the neural control unit determines the requirements for stability and generates the appropriate muscle patterns to provide the required stability. 41 this is important in preparation for predictable forces (i.e. voluntary limb movement), as well as to initiate responses to unexpected perturbations (i.e. external forces which are not under voluntary control). 13 a further mechanism which assists in spinal stability is achieved by increasing the intra-abdominal pressure via the interaction between the muscular and nervous systems. 12 spinal instability by nature the spine is classified as being unstable as a result of its structure. 27 a large number of mechanically related back pain cases may occur as a result of this inherent instability around the lumbar spine. 4 the stability of the lumbar spine is challenged on a day-today basis by a diverse range of external forces and loads acting upon it. 7 these external forces are increased in a contact sport such as rugby. the impact involved with scrumming, tackling, diving, and collisions puts increased strain on the spine and the stabilising structures which support it. spinal instability is classified into two categories: mechanical instability and clinical instability. the inability of the spine to accommodate external forces is termed a mechanical instability whereas clinical instability occurs as a result of pain or inadequate neural stimulation. 41 mechanical stability of the spine is provided by the spinal column itself as well as the surrounding muscles, especially when there are external forces acting on the spine during movement and loading. 41 most cases of back pain occur as a result of excessive and uncontrolled movement of the lumbar spine. under normal conditions stabilising subsystems work in harmony to provide mechanical stability for the spine. 24 however, in the presence of pain, or when there is a dysfunction with the low back, there is a loss in the ability of the stabilising subsystems to fulfil their role. 28 the presence of pain reduces the optimal functioning of the central nervous system and therefore the ability to maintain the muscular component of spinal stability and control. under normal conditions the subsystems work in harmony to provide mechanical stability to the spine; however, with pathology such as in low back pain there is a loss in the ability of these subsystems to fulfil their role. 24 as mentioned, this is especially the case with the neural control unit. the presence of pain reduces the optimal functioning of the neural control unit, more specifically the central nervous system and therefore the ability to maintain the active component of spinal stability. 24 individuals without any dysfunction have been shown to pre-activate their deeper abdominal muscles to aid in spinal stabilisation. 27 however, in attempting to increase the spinal stiffness around the neutral spine, individuals with chronic low back pain have shown a predisposition to increase total trunk muscle activity. 29 these individuals are not successful in their attempt to increase trunk stability at a local level (i.e. through transversus abdominus activation) as they rely mainly on global muscle recruitment (i.e. rectus abdominus activation) for stabilisation rather than more functional synergist patterns of stabilising muscles. 24 this has a negative consequence because when there is an increase in the activity of the global muscle system there is a concomitant decrease in the deeper local muscle system. 24 sajsm vol 20 no.4 2008 97 dynamic control of stability around the spine is achieved through contraction of specific muscles (i.e. the transversus abdominus) prior to movement. 24 this pre-activation controls the positioning of the centre of gravity within the base of support. 27 in healthy, pain-free individuals the transversus abdominus muscle is the first trunk muscle to activate prior to limb movement and, in this capacity, contributes towards enhancing trunk stability. 27 based on the hypothesis that the transversus abdominus contributes to a separate aspect of lumbar stability, it is predicted that the central nervous system may control components of spinal stability independently. 25 rehabilitation of low back pain as a result of its undistinguished aetiology, the treatment for low back pain remains controversial. 34 treatment options for low back pain include the following: analgesics, muscle relaxants, antidepressants, non-steroidal anti-inflammatory drugs, epidural steroid injections, manipulation, back schools, electromyographic biofeedback, traction, orthoses, behaviour therapy, transcutaneous electrical nerve stimulation, acupuncture, and exercise therapy. 49 the prevailing medical approach to the treatment of low back pain appears to consider a return to normal active daily living a more important clinical goal than pain relief. 1 there is no evidence to suggest that regular exercise increases the risk of degeneration or future back pain, and as a result controlled exercise can be seen as being safe for individuals who suffer from low back pain. 42 in fact, a lack of exercise may even play an important role in the onset of low back pain. 15 carefully selected exercises can be useful for reducing back pain intensity and back pain-related disability, and have also been associated with improved functional capacity. 42 therapeutic exercises for low back pain have been shown in 6 different randomised controlled trials to be beneficial in reducing pain by up to 60% and improving functional ability by up to 47%. 3 a cochrane review on low back pain found strong evidence that exercise therapy is an effective intervention in the treatment of low back pain. 49 when prescribing exercises for an individual with low back pain the following goals need to be considered: (i) improve performance in endurance activities; (ii) improve muscular strength around the spine; (iii) eliminate any impairments in spinal flexibility; (iv) reduce the intensity of the pain being experienced by the individual; and (v) reduce back pain-related disability. 42 these goals should be carried out simultaneously, rather than being placed in any particular order with one goal having more status or importance. with any rehabilitation process the key element is individualisation, as each individual is unique and has unique needs when it comes to rehabilitation. this has important implications in the rehabilitation process because no two low back cases are alike and therefore a standardised exercise prescription cannot be given. yet certain exercise modalities are generally prescribed in the literature as being beneficial for a specific population. in the end no exercise modality can lay claim that it is more beneficial to another, as it is what is right for the individual that counts the most. with low back pain there is an increased variability around the nature and degree of the motor control problems. 32 in a clinical situation this variability between individuals means that there needs to be an individualised problemsolving approach to the neuromuscular dysfunction rather than a ‘one-size-fits-all’ approach to prescription. 32 it is important to differentiate between treatment and prevention when considering injuries to the low back. treatment occurs after the injury has happened, while prevention reduces the risk of the injury occurring. it is critical to note that the following section is a guideline to the prevention of low back injuries. it is not possible to use this as a generalised template for treatment because no two injuries are the same. if there is any doubt over a spinal injury it is important to consult with a specialist, as certain injuries to the low back can have serious consequences if not treated appropriately. these guidelines are aimed towards the prevention of injuries rather than the treatment. for the treatment of injuries it is best to seek the guidance of a physiotherapist or biokineticist. the role of exercise (table i) there are currently a wide range of available exercises prescribed for the prevention and treatment of low back-related disorders, despite the fact that many have not been validated or scientifically studied. 1 most studies indicate that physical activity is a valuable therapeutic approach; however, there is no agreement on the specific technique, intensity, or type of exercise. 3 when reviewing the research it is clear that there is no evidence in favour of one particular exercise modality over another due to the contradictory nature of the results. 49 this is an important finding because many rehabilitation programmes claim to be the best method for the treatment and prevention of low back injuries even though there is insufficient evidence to support their superiority. 3 the best rugby-specific protocol for preventing low back injuries should therefore be to find a balance between exercise modalities, and not concentrate on just one particular mode. most rugby players are involved in some form of strength training programme to enhance their sporting performance and reduce the risk of injury. these exercise programmes often involve weight training to facilitate speed, strength, power, endurance, as well as muscular hypertrophy. the spine benefits from this type of training because the weight training indirectly strengthens the local support system. 33 furthermore, there is sufficient scientific evidence to support exercise programmes which combine multiple aspects of fitness including strength training, flexibility and cardiovascular fitness. 3 as a result there is nothing wrong with using general exercise as part of an exercise protocol to prevent spinal injuries. it is not known if core stabilisation exercises are the most appropriate exercises or if other exercises are equal or superior in reversing the motor control of the deep trunk-stabilising muscles. 32 some evidence suggests that general exercise and strength training on its own can be sufficient for conditioning the stabilisers of the low back. 33 this research is controversial because it claimed that there is no benefit in adding exercises that place an emphasis on retraining of the core. the findings were that there was a functional difference in the relative recruitment of the abdominal muscles between general strength exercises, such as weight training, and stabilisation exercises, such as pilates. 14 individuals who had a predisposition for low back-related injuries were found to activate selected abdominal muscles at low levels of their maximum ability, but following a resistance training programme these individuals could recruit a much greater percentage of their maximum. 14 from a clinical point of view this implies that general exercise, if performed correctly, may be sufficient to activate the local stabilising system in parallel with the global mobilising muscles. however, the strength training regimens that rugby players use place most of the emphasis on the global mobilising muscles rather than the local stabilising muscles. the global muscle system (mobilisers) includes the muscles that produce noticeable movement. some of these muscles also have a limited stabilisation role. these muscles are generally larger, stronger and take longer to fatigue. 98 sajsm vol 20 no. 4 2008 the local stabilising system comprises muscles that act at a defined location to limit undesirable movement. in most cases the stabilising muscles are not trained to the same extent as the global system and as a result are often weaker and fatigue easier. recently the term ‘core’ has become very popular in exercise therapy. the core is a collection of muscular structures which form a corset/brace that functions as a support for the spine. 2 in theory it is cylindrical in shape, made up of the pelvic floor at the bottom, the abdominals at the front and sides, the diaphragm at the top, and the spinal muscles at the back. the core functions like an internal weight belt because the muscles involved contract together to increase the internal pressure of the abdomen, and hence the stiffness around the lumbar spine. to visualise the role of the core imagine a soft drink can. when the can is open the thin aluminium sides can be crushed easily. when the can is closed and pressurised it is not possible to distort the shape of the can. in the case of the core, this increase in pressure is associated with an increase in muscle thickness due to muscular contraction, and is not due to the valsalva manoeuvre (breath holding). exercise programmes that address trunk muscle recruitment strategies are recommended for training the local stabilising system, especially if they include the relative activation levels of specific abdominal muscles. 45 core stabilisation is one exercise modality that focuses on the local stabilising musculature such as the transversus table i. research studies using exercise as an intervention effectiveness outcome author groups duration criteria measures outcome hansen et al. dynamic back 4 weeks reduction in pain 0 9 visual interval outcome based on sub(1993) 21 muscle exercises scale for pain groups within the low back pain population conventional physiotherapy placebo koumantakis specific muscle 8 weeks improved vas pain score no differences detected et al. (2005) 33 stabilisation functional ability mcgill pain exercise questionnaire roland-morris both groups improved general disability questionnaire functional ability exercise only tampa scale of kinesiophobia physical exercise alone pain self-efficacy is the determinant for questionnaire improvement, not the pain locus of exercise type control scale o’sullivan specific stabilising 10 weeks reduction in pain vas pain score reduction in pain and et al. (1998) 39 exercise functional disability for the reduction in oswestry low back specific stabilisation group functional disability disability after 30 month follow-up questionnaire general no significant change for the practitioner general practitioner group seferlis intense exercise 6 weeks reduction in pain vas pain score improved global back pain et al. (1998) 44 reduction in functional oswestry low back improved functional disability pain disability ability and performance questionnaire manual therapy 12 months treatment oswestry low back improvements in pain, satisfaction pain disability functional ability, questionnaire impairment, socio economic disability intensive training improvement in all groups in impairment modified borg general practitioner improvement in pain 10-point scale improvement in least satisfaction with functional ability carlsson’s pain general practitioner questionnaire treatment improvement in socio-economic disability sajsm vol 20 no. 4 2008 99 abdominus. core stabilisation is a term that has become synonymous with stabilisiation around the lumbar spine and is often referred to as core stability or core strengthening. in essence core stability is used as a broad term to encompass any exercise which requires muscular control around the lumbar spine to maintain functional stability. 2 in other words, it is the ability of the lumbo-pelvic complex to prevent deformation and to return to equilibrium after perturbation. 50 core stabilisation exercises have been promoted for lumbar stabilisation and for preventing or rehabilitating low back-related injuries because they focus on the activation of key supporting and stabilising muscles. certain key muscles have been highlighted as essential muscles involved in core stability, as their structure, function and location fulfil a supporting role for the spine. researchers have also found that the core muscles are controlled directly by the brain and activate prior to any movement. deep stabilising muscles are therefore fundamental in the central nervous system control of trunk stability and act as the centre of the functional kinetic chain. training the spinal stabilising muscles will therefore help to maintain a healthy, pain-free low back as they provide greater segmental control and support for the spine. training of the transversus abdominus is effective in the management of low back pain, as it has been shown to be the principal abdominal muscle affected. 25 the transversus abdominus has been shown to contract tonically as it produces constant tension that is maintained at a low level. 24 as a result of the loss in tonic function in low back pain, specific retraining is required to regain normal function. it is recommended that this retraining be performed independently of other trunk muscles. 25 simple stabilisation exercises have been shown to be effective in activating the abdominal muscles such as the transversus abdominus.5 isolated activation of the transversus abdominus is achieved by the inward movement of the lower abdominal wall while in the supine position in an abdominal hollowing manoeuvre, 48 as well as by specific respiratory manoeuvres. 26 conclusion a rugby player will have increased core stability/strength and a reduced risk of injury if the internal support mechanisms of the spine have been conditioned to resist distortion or injury from external forces. not only will improved core stability benefit players on the field during matches or practices, it will also assist in preventing unnecessary injuries during weight training and pre-season conditioning. simply adding selected core stability exercises to a rugby player’s exercise routine will reduce the risk of injuries to the low back and core. it is important to clarify that it is insufficient to only train one aspect of the core, as is often the case. there is a great misconception that by performing numerous crunches and sit-ups the core will be strengthened. in fact, the opposite can be true because by overloading one aspect of the stabilising system you leave the other areas vulnerable and weak, which is why an intricate balance of exercises is required to target all muscles involved in spinal stability. if the injury rate to the low back and core is to be reduced, coaches and conditioning experts need to implement the best practice guidelines outlined in this article. the take-home message is that adequate stabilisation of the spine is the key factor in the prevention of injuries to the low back and core. this stabilisation is important to prevent hypermobility and loss of control around the lumbar spine. it is for this reason that exercise programmes that combine core stability with general strength training should be prescribed for rugby players to prepare them for the level of impact involved in the game, as well as for sport-related weight training and non-sporting-related daily activities. acknowledgements the paper was commissioned by the boksmart programme, which is a national programme sponsored by absa and implemented on behalf of the south african rugby union and the chris burger/petro jackson player’s fund. the goal of the programme is to teach safe and effective techniques, which will reduce the incidence and severity of injury, make the game safer for all involved and improve rugby 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the most common interventions. spine 1997; 22: 2128-56. 50. willson jd, dougherty cp, lloyd ireland m, mcclay davis i. core stability and its relationship to lower extreme function and injury. am acad orthop sur 2005; 13: 316-25. sajsm vol 20 no. 4 2008 101 original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license addressing negative psychosocial factors linked to severe injury in professional rugby players: an introduction to a group psychotherapy approach t m hall,1 ma; j a botha,2 phd; j s patricios,3 mbbch ffsem (uk) 1 counselling psychologist, private practice, kenilworth, western cape, south africa 2 clinical psychologist, private practice, netcare waterfalls, johannesburg, south africa 3 sport and exercise medicine physician, wits sport and health (wish), faculty of health sciences, university of the witwatersrand, johannesburg corresponding author: t m hall (psychology@trevorhall.co.za) professional rugby union (rugby) has become a viable means of earning a living for many players. however, club salary caps, as well as international limitations on squad numbers, are escalating the need for administrators to protect existing contracted players from adverse factors associated with the professional game, including injuries and cmd.[1] high rates of severe rugby injury (sri) (i.e. > 28 days recovery) found in professional rugby can be costly to teams and to individual players physically, financially, and psychosocially.[2] a growing body of literature outlines negative psychosocial sequelae of sri that seem to be experienced in a stage-wise progression similar to the effects of a trauma experience.[3,4,5] documented negative psychosocial sequelae of sri include feelings of fear, grief, loss, stress, and trauma reactions,[6,7] as well as the added risk for the onset of cmd (e.g. distress, anxiety, depression, and sleep disturbance).[1] regarding cmd, gouttebarge et al.[1] found that the prevalence of anxiety and depression in the international elite rugby population was slightly higher than in general occupational populations. these authors suggested that severe time-loss musculoskeletal injuries are contributing stressors linked to higher rates of cmd onset. furthermore, it stands to reason that psychosocial sri reactions and the onset of cmd can affect a player’s physical injury recovery, quality of life and his/her ability to recover playing form.[1,6,7,8] recently, multiple researchers have suggested that more needs to be done in both understanding and addressing welldocumented negative psychosocial sequelae of sri that seem to be a common risk factor in the onset of cmd within the professional rugby population.[1,6] a multidimensional approach to sri recovery when attempting to understand sri, the recovery experience, and how best to create effective recovery protocols, it is appropriate to consider multiple dimensions of this experience. chang et al.[9] in their position statement on mental health issues and psychological factors in athletes suggested that severe injuries are a contributing factor to mental health disorders in the elite athlete population. these authors advised that sport physicians, along with other care providers, when medically intervening with elite athletes, should be aware of relevant psychological, cultural, and environmental influences. gouttebarge et al.[1] also suggested that psychological attention should be included in the medical care of professional rugby players. hall[3], drawing from the biopsychosocial model of sports injury rehabilitation processes,[10] suggested that sri affects the individual professional rugby player across biological, psychological and social dimensions of their life-world. the biopsychosocial model of sports injury rehabilitation considers seven dimensional influences: injury characteristics, sociodemographic factors, biological factors, psychological factors, social and contextual factors, intermediate biopsychosocial outcomes, and sports injury rehabilitation outcomes.[10] hence, the design of a psychotherapeutic intervention aimed at lessening the potential harmful effects of sri should consider as many dimensions of the injury experience as possible. for the purposes of this paper, however, focus is drawn to rugby professional socio-cultural and psychosocial developmental factors taken into account in the design of the rmg. socio-cultural factors the professional rugby environment is generally one of routine, background: negative psychosocial sequelae of severe rugby injury (sri) in professional rugby players are well documented. unaddressed, these issues can leave players vulnerable to persistent common mental disorders (cmd) and negatively affect injury recovery processes. objective: to introduce a psychotherapeutic group intervention aimed at addressing negative psychosocial sequelae linked to sri in professional rugby player cohorts. methods: literature aimed at clarifying the potential efficacy of an integrative group therapy model, the recovery mastery group (rmg), is discussed after which component parts of the intervention are presented. case illustration: a case illustration is presented comprising examples of how the rmg framework addressed psychosocial recovery issues in a professional south african rugby team during 2019. conclusion: the proposed recovery mastery group (rmg) is presented as a costand timeeffective psychotherapeutic intervention that integrates well-researched psychotherapeutic techniques. the rmg appears able to address multiple facets of psychosocial injury recovery, while possibly offering protection from the onset of cmd. this introduction to the rmg can be a forerunner of similar research across larger cohorts, in different team sports, to determine wider therapeutic intervention efficacy. keywords: psychosocial sequelae, mental health, rugby, injury s afr j sports med 2020;32:1-7. doi: 10.17159/2078-516x/2020/v32i1a8505 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8505 https://orcid.org/0000-0002-4547-2971 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0003-4472-9963 original research sajsm vol. 32 no. 1 2020 2 rituals and to a degree, tribal behaviour.[11] players live and work within a somewhat closed system that is potentially sceptical of outsiders, such as psychotherapists. a documented lack of psychotherapeutic referral networks, time and financial constraints,[6] and a paucity of psychoeducation around psychosocial expectations of injury recovery,[1,3,6] ongoing negative stigma associated with acknowledging the onset of cmd and seeking out psychotherapeutic assistance[1,6] seem to precipitate professional rugby players’ reliance on insider (e.g. teammates and medical professionals) support structures during sri recovery rather than the seeking out or acceptance of external assistance, such as psychotherapists.[3,6] a psychotherapeutic intervention aimed at lessening psychosocial risk associated with the negative effects of sri should consider the creation of support structures coming from within the rugby environment and hence, possibly minimising risk of stigma towards seeking psychotherapeutic support. psychosocial developmental factors in addition to the abovementioned example of socio-cultural factors that can affect sri recovery protocols, age-related psychosocial developmental factors should also be considered. shinke et al. [8] in their position stand on athlete’s mental health, performance and development suggested that injured elite athletes experience heightened pressure situations during early adulthood. early adulthood is a developmental stage wherein individuals are most vulnerable to the onset of psychopathology.[8,12] furthermore, early adulthood includes individuals seeking out intimacy in both platonic and romantic relationships, the achievement of which can lessen the risk of the development of mental health disorders.[12] it would, therefore, be reasonable to assume that professional rugby players, experiencing sri during the psychosocial stage of early adulthood would benefit from interventions that considered opportunities for the injured player to form both close relationships and networks of support. psychotherapeutic interventions allied to sport rehabilitation processes exist.[10] these interventions include educational interventions, goal setting, imagery for performance, imagery for rehabilitation, self-talk-based interventions, biofeedback, and social support-based interventions.[10] however, it seems as though no psychotherapy intervention currently exists that takes advantage of opportunities presented in team-specific environments for interpersonal learning, relationship building, and real-time skills acquisitions that are documented as being protective factors against the onset of cmd.[13] objective this paper aims to introduce a psychotherapeutic group intervention designed to address negative psychosocial sequelae linked to sri in professional rugby player cohorts, while also lessening risks associated with the onset of cmd. in order to achieve these aims, the components of the group therapy intervention named the recovery mastery group (rmg) will be discussed and outlined as a methods section. following the methods section, a short case illustration describing the implementation of the rmg within a professional south african rugby union team will be presented. as this paper aims to introduce the rmg, the group therapy’s component parts, as well as their reciprocal relationships are the focus of the case illustration. individual group members’ biopsychosocial case histories, injury details, and specific sri reactions are important facets in a discussion around focused therapeutic outcomes; however, they are not the focus of this paper. methods literature supporting the implementation of group therapy as a viable, evidence-based practice in addressing and even redressing clinical and sub-clinical mental disorders in general populations is well established.[13] group therapy processes are often defined by the members that make up the group, as well as the collective aims of the group.[13] furthermore, it is the group itself that enables therapeutic factors – the group therapist often takes up a facilitator role aimed at encouraging interpersonal and relational processes.[13] this section describes the three therapeutic components of the proposed group therapy intervention, and their integration within the professional sri population. the recovery mastery group (rmg) the rmg was designed as a timeand cost-efficient,[13] openended group psychotherapy process. the rmg serves as a purposeful insider, psychosocial, developmentally appropriate support structure. therapeutic time and cost-efficiency are important factors to consider in the professional rugby environment. time is often taken up by a variety of essential daily conditioning, strategy, training, and recovery tasks. furthermore, team budgets do not often include psychotherapeutic concessions. group therapy sessions are frequently regarded as being cost-effective due to the facilitator being able to see many participants at once.[13] players can attend weekly rmg sessions at their specific clubs during days already allocated to recovery protocols. additionally, on-site sessions, consistently facilitated by a team psychologist, might create the perception of the group process as coming from insider support rather than potentially threatening outsider ones. this can reduce issues of stigma associated with psychotherapy, while promoting therapeutic adherence and the greater likelihood of effective recovery outcomes.[14] the rmg employs the integration of yalom’s[13] therapeutic change mechanisms, a stage-wise wits trauma framework that serves as a collection of interchangeable guiding principles of trauma recovery[15], as well as guided imagery techniques that have been documented as being effective in promoting injury recovery, general well-being, and sports performance.[10] regarding integrated psychotherapy, the incorporated framework, change mechanisms, and specific techniques work original research 3 sajsm vol. 32 no. 1 2020 together to affect change,[16] as is discussed in the case illustration. rmg therapeutic factors yalom[13] suggested that the efficacy of group therapy is due to present-focused, ‘here and now’ therapeutic change mechanisms that exist within the process/relational aspects of the group itself. yalom’s change mechanisms include: the instillation of hope, universality, imparting of information, altruism, corrective re-enactment of the primary family group, development of socialising techniques, imitative behaviour, interpersonal learning, group cohesiveness, catharsis, and existential factors.[13] general, positive relational experiences aligned to interpersonal learning, group cohesion, universality, and the instillation of hope can be considered protective factors against the onset of mental health issues during early adulthood.[12] they have also been documented as being supportive elements that might promote injury recovery efficacy in rugby and sporting populations.[6,7] considering the trauma-related effects of severe rugby injury (e.g. fear and stress reactions), the abovementioned group therapy change mechanisms should be experienced and integrated within an interchangeable stage-wise trauma therapy framework. rmg trauma therapy framework a major factor in addressing experiences of both physiological and psychological trauma is how effectively an individual is able to reconstruct idiosyncratic meaning structures that have been shattered by the traumatic event.[15] the rmg incorporates the south african-developed wits trauma model[15] as a framework for both understanding and ‘working with’ sri trauma reactions. the wits trauma model consists of a five-stage interchangeable therapy framework: telling/retelling the trauma story, normalising symptoms, addressing guilt and self-blame, encouraging mastery, and facilitating the creation of meaning. the framework aims at re-attaching meaning to both the traumatic event and the individual’s life, while striving towards trauma mastery.[15] regarding the rmg, the trauma therapy framework is employed as a set of ‘guiding principles’ from which group therapy change mechanisms might operate. for example, an injured player might feel compelled to tell/retell the story of her/his injury onset within the group, thus providing her/him the opportunity to experience change mechanisms, such as catharsis, universality, and ‘real-time’ interpersonal learning. furthermore, the integration of a guided imagery technique at the outset of every session presents the group members with a practical approach to mitigating stress reactions, as well as with a platform from which to share pertinent recovery protocols and experiences. rmg guided imagery techniques originally, the rmg included a mindfulness awareness technique aimed at promoting stress reduction, pain management, and the development of a strong mind-body connection.[17] however, some group participants experienced this technique as being stress-promoting due to them not being able to retain focused awareness on themselves. it was then decided to employ guided imagery techniques, which is more experience-focused rather than awareness-focused. this change is discussed in the case illustration below. the inclusion of guided imagery techniques within the rmg framework aims to address potential negative affective states found within the injured professional rugby player population, while promoting motivation for recovery outcomes.[10] the technique includes individuals being asked to imagine certain scenes and then being guided through a series of visualised experiences. research on the effects of guided imagery and visualisation techniques in competitive sports suggest that these techniques can promote relaxation, lessening of stress and anxiety, bolstered self-confidence, and improved sports performance. regarding, sports injury rehabilitation, guided imagery has been shown to assist in muscle relaxation, the reduction of stress hormones, the promotion of recovery motivation, and coping with pain and negative emotions.[10] in summary, the rmg attempts to integrate yalomian group therapy change mechanisms, the wits trauma model, and guided imagery techniques in order to promote psychosocial sri recovery in both timeand cost-effective ways. case illustration the following section illustrates the implementation of the rmg with a south african professional rugby team during 2019. attention is drawn to examples of how this group’s experiences of sri psychosocial reactions were addressed via the integration of the overarching rmg trauma recovery framework, rmg therapeutic change mechanisms, and guided imagery techniques. group member recruitment eight players were recruited from the team. the ages of the participants ranged from 19 to 32 years old. members included those players who had experienced an sri and who medical personnel, including the team sports physician, perceived as showing concerning psychological and behavioural changes during their recovery. chang et al.[9] suggested that sports physicians and other sports medical personnel are uniquely situated to detect the need for psychological support in the elite athlete population. differences in age, experience, and injury recovery stages promoted a heterogeneous group makeup that encouraged cross-experiential, interpersonal learning.[13] group structure due to the open-ended structure of the group, two newly injured players entered into the rmg during the 12 sessions and one player, who had recovered, exited the group after session 10. each session began with an introduction which included group rules and the necessity for confidentiality. the group then took part in a fiveto seven-minute guided imagery exercise. the group experience was thereafter unstructured until the final five minutes comprising the closing ritual (in this case, selecting two group members who would supply the original research sajsm vol. 32 no. 1 2020 4 rmg with coffee the following week). group sessions were 60 minutes long and facilitated during a time in the training day when no other team activities had been prepared. hence, both newly injured and ‘returning to play’ group members would be able to attend. experiences of rmg therapeutic factors the following case information, including pertinent sri group psychosocial themes and group member feedback, was gleaned from facilitator process notes. presented case information was selected by the authors perceived as being relevant in outlining the intended reciprocal relationship between the aforementioned rmg therapeutic factors. paraphrased vignettes, intended to protect the identities of group members, are employed as examples of group member experiences. themes of negative psychosocial sequelae linked to sri included group members’ experiences of disbelief at the onset of the sri, feelings of isolation, fear related to recovery and future performance, socially avoidant behaviours, experiences of both diminished hope and self-confidence, as well as individual difficulties in understanding emotional reactions to injury. these factors were consistent with those found in the literature exploring psychosocial sequelae of sri.[2,3,4,5,6] examples of how the integration of rmg therapeutic factors, mindfulness and guided imagery techniques, as well as how confrontation and relating in the group process addressed group specific themes of sri reactions, are presented below. integration of rmg therapeutic factors firstly, the rmg afforded group members opportunities to normalise feelings of isolation, fear, and diminished hope by allowing them to recite their experiences in the group setting. the telling and retelling of the trauma experience and the normalisation of psychological trauma symptoms have been documented as being effective therapeutic tools in processing trauma.[15] for example, group member b, disappointed at the timing of his injury (in his first game back after being previously injured), consistently steered the group conversations towards his experience of injury onset. he seemed to need to tell and retell the story of his re-injury experience.  ‘… i mean, it happened … again … i remember when i felt it go – whack – i knew it was gone again … all i could think about was, ‘… not again, not again … what’s my dad going to say? how am i going to go through another six months, sitting at home with my parents?! … i know i’ve said this before, it’s just … you know’ secondly, the rmg appeared to address the aforementioned sri psychosocial themes via the integration of interpersonal learning and experiences of universality: two group therapy change mechanisms that have been documented as being useful in addressing an array of negative psychosocial symptoms, including trauma and existential issues.[13,14] on one occasion, group member c mentioned that he too thought of his mother and sister at the time of his injury and that he would often repeat the injury experience in his mind. the group setting allowed for the telling and retelling of the injury stories, while group members experienced the normalisation of trauma symptoms via group interpersonal learning.  ‘… i remember thinking, … “this could be bad … what’s going to happen now, i’m in my last year of contract and my mother needs the money!” … i mean, i still think about what happened, even though i know i’ll get better, i still go over it in my head … its irritating … maybe its normal … i mean, thinking about what happened all the time’ group member a (an experienced player) commented on the exchange between b and c. he suggested that he too experienced recurring frustrations around how his injury had occurred but he reassured b and c that these thoughts would eventually dissipate and that they would begin to focus on using their recovery processes to become better players, overall.  ‘… its annoying to keep thinking about these things [injury onset] but i promise, eventually, it gets better … eventually you start to think, ‘… this is time i have to make myself better!’ … we hardly get time to improve on things during the season … so you can use this time, now … it gets better, i promise’. group member a had inadvertently instilled hope, outlined a universal theme of shared injury experiences, and presented an opportunity for interpersonal learning. the above interaction took place within the framework of the telling/retelling of the injury/trauma story, normalising trauma symptoms, and developing an opportunity for mastery of the trauma experience. the group structure seemed to create a platform from which injured rmg members could experience connectedness rather than isolation, as well as the instillation of hope for both future recovery and performance – positive psychosocial responses to sri that can promote recovery efficacy.[6,7] this would have been difficult to achieve outside of a group session. during group member feedback sessions, a, b, and c mentioned that the rmg sessions had assisted them in creating experiences of ‘friendship’, ‘connection’, and ‘meaning through learning from each other’. mindfulness and guided imagery techniques a mindfulness technique comprising becoming aware of one’s breath and a gradual, systematic non-judgmental awareness of each major body part[17] was initially employed at the beginning of the first three rmg sessions. some group members suggested that they experienced difficulties in maintaining a detached awareness of their body parts, due to physical pain and the need to perform. group member d indicated that he struggled to maintain an awareness of his injured body part without judging himself in a harsh and angry way. he expressed to the group that he felt like he was not ‘doing it right!’. d seemed to experience behavioural stress in his need to ‘perform’ in the ‘detached’ mindfulness space.  ‘… can you guys do it? … i can’t focus … i keep thinking of my injury, and i’m angry … you say “be aware of your neck” and original research 5 sajsm vol. 32 no. 1 2020 i just go straight to my knee! …, that was hard! …’ group member e, however, declared that he found the mindfulness exercise incredibly relaxing, but, that he had meditated previously. he proposed that those group members who found it difficult to maintain a detached awareness of themselves potentially lacked experience in meditation and that they would eventually learn to feel relaxed if they continued to practice meditation.  ‘i actually feel super relaxed! … i’ve done this before, though … i learnt to meditate a while back when i was looking for things to help me relax … it takes practice though … you’ll get it … the trick is to not try too hard. sounds strange but it’s true …’ due to the discrepancy in expressed experiences related to the mindfulness practice, it was decided to shift from an awareness experience to a guided imagery technique for the next session. the guided imagery exercise comprised the facilitator narrating a ‘mind journey’ during which the group members were asked to participate in specific imagery and ‘feeling’ exercises. guided imagery techniques such as this one are frequently employed to increase feelings of relaxation, and decrease experiences of stress and anxiety.[10] after the application of the guided imagery technique, group member d exclaimed that he felt that the experience was very powerful. he suggested that he preferred this technique to the previous week’s one.  ‘… that was powerful! i literally felt like i was a tree with strong roots!’ according to rmg member feedback sessions, differences exist in how severely injured rugby players experience various mindfulness and guided imagery practices. according to this case illustration, guided imagery techniques were preferred by the group, as a whole, when compared with the mindfulness practice. confrontation and relating in the group process beginning the group sessions with a guided imagery practice often encouraged group discussions around how members experienced this practice. frequently, these discussions would lead to session material and group processes that could be explored. for example, during the abovementioned session when group member d expressed his difficulty in maintaining awareness, the facilitator asked which other group members had similar reactions. the facilitator noticed that group member f, a junior player, looked as if he want to add to the discussion but would then sit back in his chair, letting other members speak. the facilitator brought the group’s attention to f potentially wanting to add something. group member g, a friend of f commented, while laughing and in a ‘bantering’ manner, that f ‘never speaks his mind’.  ‘… f doesn’t say much! he’s quiet, that’s his thing … and he’s a scrumhalf!’ f had struggled during his recovery process to communicate recovery information to the medical team. he would often not say that he was experiencing fatigue or pain. he would then avoid certain conditioning sessions in favour of rest or physiotherapy without communicating his decision to the parties involved. this pattern was negatively affecting his relationships with the medical personnel and the coaches. group member a joined in on the banter and cajoled f into ‘speaking up’.  ‘… the guys are teasing you hey! you better say something … they not going to stop hassling you now!’ f eventually commented that he also struggled with the mindfulness technique. the facilitator asked f what he thought of the banter that was directed towards him. f suggested that he was a junior player and that he wanted to be respectful to the seniors in the team but that the banter was fine.  ‘i don’t want to say too much … i’m a junior and it’s important to be respectful … i don’t mind being teased, its actually nice … it’s nice that we [juniors] can talk like this with guys like a who have been there [experienced players]’ although this group experience was somewhat confrontational for f, he seemed to feel supported by the other ‘bantering’ members. the facilitator used the discussion to broach the topic of communication. group member a reiterated the importance of being able to confront teammates and even coaches, at times. f stated that he struggled to talk to coaches about how his recovery was going for fear of them seeing him as weak or lazy.  ‘… i feel like i’m lucky to be here … if i’m tired or sore, i don’t want the coaches to know … they’ll think that i’m trying to get out of stuff or that i shouldn’t be here [contracted]’ the group discussed f’s assumptions around what would happen if he communicated openly to coaches. there was a consensus that it was vitally important to speak to coaches and other personnel regarding recovery experiences and even when returning to play. the following rmg sessions involved group members continuing to express ‘banter’ towards f. the facilitator noted that f began to engage with the group more than previously. interestingly, during a medical meeting, one of the medical personnel team commented that f had spoken to him about his recovery protocols and that f had asked him if they could change some of the conditioning routines to ones that f felt were more beneficial to him. the abovementioned process seemed to address issues of diminished self-confidence, communication, and avoidant behaviours via real time confrontation within the rmg. group members were able to relate to each other between junior and senior hierarchies, while learning skills that were then applied to situations outside of the group context. the translation of ingroup relational processes to daily life situations is regarded by yalom as an indication of group therapy efficacy.[13] in summary, the implementation of the rmg within this specific population seemed to promote desirable individual experiences of telling and retelling the injury story, the normalisation of trauma symptoms, interpersonal learning, experiences of universality, and the instillation of hope. guided imagery practices reportedly assisted members with stress original research sajsm vol. 32 no. 1 2020 6 reduction, while supportive confrontations and inter-member relating assisted members in learning communication skills. generally, group members reported experiencing increases of general feelings of empowerment by the end of the rmg process. the rmg psychotherapeutic factors mentioned have been proven to mitigate the negative effects of trauma, protect against psychological vulnerability and, in some cases, promote effective injury recovery.[1,3,4,10] limitations this paper is intended to introduce the rmg as a potentially effective group psychotherapeutic intervention aimed at addressing negative psychosocial sequelae linked to sri in professional rugby player cohorts. however, there are various limitations regarding its presentation.  firstly, the case illustration was drawn from the group facilitator’s process notes and contextualised in terms of existing group and individualised psychotherapy interventions. no quantitative data referring to therapeutic efficacy exists.  secondly, individual group member data, including age, injury type, recovery stage, and general biopsychosocial case histories were not included in this paper. general therapeutic outcomes were presented as being allied to overarching rmg processes rather than to specific individual factors.  thirdly, and due to limited individual biopsychosocial data, reasons for the outlined discrepancy between the inclusion of guided imagery practices as opposed to mindfulness techniques is not clear.  finally, interpretations are subjective and, therefore, not necessarily generalisable. future research in light of the outlined limitations of this paper, further research should include both quantitative and qualitative methods that could elucidate which specific rmg factors produce specific outcomes. furthermore, studies focused on the discussed discrepancy between guided imagery practices and mindfulness techniques within the sri population could add to the literature on this topic. finally, research aimed at understanding differences between the effectiveness of ‘insider’ vs ‘outsider’ support structures could yield valuable data for validating rmg processes. conclusion this paper introduced the concept of a timeand cost-effective group psychotherapeutic intervention aimed at addressing negative psychosocial effects of sri and lessening the risk of the onset of cmd in the professional rugby player population. documented negative psychosocial reactions to sri and recently documented levels of cmd within the professional rugby population have highlighted the need for specific ‘insider’, consistent, psychosocial support structures within professional rugby. the rmg takes advantage of the somewhat unique professional rugby environment in order to create an ‘insider’ support structure focused on developmentally appropriate relationship building and interpersonal learning. although more research on the efficacy of specific rmg factors is needed in order to validate the intervention, the authors of this paper would recommend the rmg as an effective therapeutic intervention for this specific population. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: th; lead author, conception, design, analysis, and interpretation. jb; editing and supervision to initial draft. jp; senior author, drafting, critical revision, editing, supervising. references 1. gouttebarge v, hopley p, kerkhoffs g, et al. symptoms of common mental disorders in professional rugby: an international observational descriptive study. int j sports med 2017;38(11):864-870. [doi: 10.1055/s-0043-114010] [pmid: 288956197] 2. schwellnus mp, thomson a, derman w, et al. more than 50% of players sustained a time-loss injury (>1 day of lost training or playing time) during the 2012 super rugby union tournament: a prospective cohort study of 17 340 player-hours. br j sports med 2014;48(17):1306-1315. [doi:10.1136/bjsports2014-093745][pmid: 24982503] 3. hall tm. south african professional super rugby players’ lived experiences of career-related traumatic injuries: a phenomenological analysis (unpublished minor dissertation). auckland park, university of johannesburg, 2018. available from: [http://hdl.handle.net/10210/279170] 4. roy j, mokhtar ah, karim sa, et al. cognitive appraisals and lived experiences during injury rehabilitation: a narrative account within personal and situational backdrop. asian j sports med2015;6(3):e24039. [doi:10.5812/asjsm.24][pmid: 26448849] 5. van der poel j, nel p. (2011). relevance of the kübler-ross model to the post-injury responses of competitive athletes. s afr j res sport ph;2011;33(1):151-164. [doi: 10.4314/sajrs.v33i1.65496] 6. arvinen-barrow m, massey wv, hemmings b. role of sports medicine professionals in addressing psychosocial aspects of sport-injury rehabilitation: professional athletes’ views. j athl train 2014;49(6):764-772. [doi:10.4085/1062-6050-49.3.44] [pmid: 25243737] 7. carson f, polman rc. self-determined motivation in rehabilitating professional rugby union players. bmc sports sci med 2017;9(2):1-11. [doi:10.1186/s13102-016-0065-6] 8. schinke rj, stambulova nb, si g, et al. international society of sport psychology position stand: athlete’s mental health, performance, and development. j sport exerc psychol 2018;16(6):622-639. [doi: 10.1080/1612197x.2017.1295557] 9. chang c, putukian m, aerni g, et al. mental health issues and psychological factors in athletes: detection, management, effect on performance and prevention: american medical society for sports medicine position statement – executive summary. br j sports med 2020;54(4):216-220. [doi:10.1136/bjsports-2019101583][pmid:31810972] 10. santi g, pietrantoni l. psychology of sport injury rehabilitation: a review of models and interventions. j hum sport exerc 2013;8(4):1029-1044. [doi:10.4100/jhse.2013.84.13] 11. hough pa, nel m, de klerk t, et al. roles, rituals and emotional regulation of rugby players at different competitive levels. s afr j occup ther 2019;49(1):51-57. http://hdl.handle.net/10210/279170 doi:%2010.4314/sajrs.v33i1.65496 doi:%2010.4314/sajrs.v33i1.65496 original research 7 sajsm vol. 32 no. 1 2020 [doi: 10.17159/23103833/2019/vol49nla8] 12. robinson oc. emerging adulthood, early adulthood and quarter-life crisis: updating erikson for the twenty-first century. in: z ̌ukauskiene r, ed. emerging adulthood in a european context. new york: routledge, 2015: 17-30. 13. yalom id, leszcz m. the theory and practice of group psychotherapy. 5th ed. new york: basic books, 2005. 14. macnair-semands rr, lese kp. interpersonal problems and the perceptions of therapeutic factors in group therapy. small group res 2000;31(2):158-174. [doi: 10.1177/104649640003100202] 15. eagle g. an integrative model for brief term intervention in the treatment of psychological trauma. ijp 1998;3(2):135-146. available from: [https://search.proquest.com/docview/212044456?pqorigsite=gscholar&fromopenview=true] 16. norcross jc, beutler le. integrative psychotherapies. in: wedding d, corsini rj. eds. current psychotherapies. 9th ed. s.l.: brooks/cole, 2010. 17. kaur h. mindfulness and meditation in sports. ieasrj 2018;3(6):1-2. available from: [http://ieasrj.com/journal/index.php/ieasrj/article/vie w/157] doi:%2010.1177/104649640003100202 doi:%2010.1177/104649640003100202 https://search.proquest.com/docview/212044456?pq-origsite=gscholar&fromopenview=true https://search.proquest.com/docview/212044456?pq-origsite=gscholar&fromopenview=true sajsm vol. 27 no. 2 2015 33 original research background. global positioning system (gps) technology can provide accurate, non-invasive, real-time movement analysis of players participating in team sports. the application of this technology to rugby union will improve training practices by allowing improved understanding of movement characteristics and more individualised programmes. objectives. to characterise the movement and impact patterns of south african professional rugby union players during match play and compare these to previously reported data. methods. nineteen professional rugby players were tracked using gps systems during 24 matches during the 2013 rugby season. players were grouped as (i) backs or forwards and (ii) tight forwards, loose forwards, scrumhalves, inside backs or outside backs. movements were categorised in speed zones corresponding to walking (0 2 m.s-1), jogging (2 4 m.s-1), striding (4 6 m.s-1) and sprinting (>6 m.s-1). walking and jogging were classified as low-intensity and striding and sprinting as high-intensity movement zones. an inbuilt triaxial accelerometer (sampling frequency 100 hz) measured the total impacts >5g and high-intensity impacts >8g. all data were normalised to time on field and reported as mean (standard deviation). results. there was no difference between forwards and backs in relative distance covered. backs reached higher maximum speeds than forwards (backs 8.8 (1.1) v. forwards 7.6 (1.3) m.s-1, effect size (es) 1.0, and outside backs were the fastest positional group (9.4 (0.9) m.s-1, es 0.4 2.2). players in all positions spent the majority of time walking (79 84%). backs covered more distance than forwards in high-intensity speed zones (forwards 11 (5) v. backs 14 (4) m.min-1, es 0.7). tight forwards covered the most distance in low-intensity zones (63 (6) m.min-1, es 0.3 1.7) while scrumhalves ran the most distance in high-intensity zones (20 (5) m.min-1, es 1.2 3.6). highintensity :  low-intensity running ratios ranged from 1:13 (tight forwards) to 1:3 (scrumhalves). loose forwards and inside backs exhibited similar movement patterns. there was no difference in impact variables between forwards and backs. inside backs sustained the least total impacts (6.5 (1.2) >5g.min-1, es 0.9 2.0) and high-intensity impacts (0.7 (0.2) >8g.min-1, es 0.5 1.4). conclusions. there were notable differences in the movement of professional rugby union players in different positions, and effective training programmes should reflect these variations. s afr j sports med 2015;27(2):33-39. doi:10.7196/sajsm.566 movement and impact characteristics of south african professional rugby union players j c tee, msc (exercise science); y coopoo, dphil, facsm department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa corresponding author: j c tee (jasonctee@gmail.com) rugby union is a full contact sport during which players are involved in short-duration, high-intensity efforts, which often involve high-speed collisions, interspersed by low-intensity periods of standing, walking and jogging.[1] playing positions are individually named and reflect distinct roles within the game, but are commonly grouped with other positions with similar attributes to create designations such as ‘forwards ‘ and ‘backs’, and ‘tight-five’, ‘loose forwards’, ‘inside backs’ and ‘outside backs’.[1,2] all players are required to perform core skills such as tackling and rucking during a match, but the physical and skill demands of the playing positions are different.[1] forwards are generally involved in actions to contest for and retain possession of the ball and are exposed to high volumes of physical contact as a result.[1,2] backline players are regularly involved in the execution of tactical movements to gain field position or score and are able to run more freely with less contact involvements.[1,2] to ensure the conditioning and recovery programmes of the players are appropriate, it is essential to have a good understanding of the physical demands placed on players in these different positions.[3] a number of researchers have endeavoured to quantify the physical demands of rugby union through video-based time-motion analysis (tma).[1,2,4-6] these studies all agree that the majority of time is spent engaged in low-intensity activities for all positions, but that the nature of physical exertion differs across position groups. researchers have previously determined that backs spend more time in low-intensity activity than forwards,[6] but also that backs spend more time sprinting than forwards.[1] when divided into four positional groups (front row forwards, back row forwards, inside backs and outside backs), back row forwards were shown to spend the greatest amount of time engaged in high-intensity activity, while inside backs covered the most total distance.[6] rugby union has evolved rapidly owing to intermittent law changes making it necessary to continuously re-evaluate game demands.[7] while video tma has provided a great deal of valuable information to researchers, its practical application is somewhat limited considering the time required for coding movement events and subjectivity in the categorisation of locomotive events.[8] the development of global positioning systems (gps) that provide accurate, non-invasive movement analysis for team sports has reduced the time required for tma.[8] as a result, research has emerged describing the motion characteristics based on gps of a 34 sajsm vol. 27 no. 2 2015 variety of sports including rugby union, rugby sevens, rugby league, australian football league, field hockey and football.[9] to date, only four studies have been published describing the movement characteristics of elite professional rugby union players.[3,10-12] the first two of these, cunniffe et al.[3] and coughlan et al.,[10] used similar methodology: tracking a single forward and a single back during an international rugby union match. the results were similar: players covered >6 500 m in both studies and the backs performed a greater number of high-intensity runs and reached greater maximal speeds than the forwards did. a major limitation of both of these preliminary studies is that they observed only two players on single occasions, and as such it is difficult to generalise this information. reid et al.[12] examined eight players from different positions in a single match and reported a range of relative running distances from 67.0 to 78.2 m.min-1. furthermore, they reported that backs covered the most distance walking, while forwards covered the most distance jogging.[12] cahill et al.[11] provided a comprehensive study that observed players from a variety of english premiership clubs over the course of a season. they showed that although all players covered relatively little distance while sprinting, loose forwards sprinted the most. furthermore it was shown that backs covered greater relative distances than forwards, scrumhalves covered the greatest total distance and tight forwards the least.[11] the validity and reliability of the spi-pro gps unit (gpsports, australia) has been previously established.[8,13] in particular, the validity for speed zones walking (standard error of estimate (see) 1.0% (0.4%)), jogging (see 3.7% (1.4%)) and striding (see 3.0% (1.1%)) is strong.[13] the validity of distance measures in sprint zones (>5 m.s-1) is less accurate (see 10.5% (3.9%)), typically underestimating sprint distance and should be interpreted carefully.[13] gps units have been shown to reliably measure peak velocity (coefficient of variation (cv) 2.3, 90% confidence interval (ci) 2.1 6.6).[8] this indicates that absolute sprint counts may be more accurate as a measure of high speed exertion than high-speed running distance. gps is a powerful tool for analysis of movement characteristics, but is unable to record time or effort spent in static exertions. deutsch et al.[2] reported that forwards spend approximately 10 minutes per match engaged in static, high-contact activities like tackling, scrumming, rucking and mauling. these activities will not be recorded by gps monitoring but make up a significant portion of game exertion. physical contact has been shown to lead to reductions in total, lowintensity and high-intensity running v. non-contact games.[14] in an attempt to quantify these additional loads, manufacturers of gps devices have included a triaxial accelerometer to measure impact forces. the validity of these accelerometer measures has not been established. waldron et al.[15] showed the reliability of accelerometer measures to be disappointing (cv 4.7 5.2%). interpretation of accelerometer data is complicated because acceleration peaks result from a variety of actions including foot strikes, running, jumping, falling, tackling and rucking. researchers have not shown any correlation between high-intensity impacts and collision events like tackles during rugby league matches.[16] despite this, research has shown correlations between high-intensity impacts (>8g) and markers of muscle damage[17], as well as neuromuscular markers of post-match fatigue[16] in rugby league. accelerometer data have not previously been reported in elite rugby union competitions, and may be of some value in terms of quantifying physical impacts sustained and planning recovery strategies. rugby union is thought to display variations in the pace of the game played in different hemispheres as a result of differing playing conditions and styles. this assertion is supported by statistics comparing the six nations and tri nations competitions, the premier international competitions in each hemisphere. analysis of these competitions from 2008 to 2011 indicates that the ball is in play for more time per match in six nations matches (49 v. 45%).[18] the objective of this study was therefore to provide normative data for movement and impact characteristics of player’s participation in south africa (sa)’s elite professional rugby competitions and to compare these data with previous research from other countries. methods participants a prospective, observational, longitudinal design was used to assess the movement and impact characteristics of players from an sa professional rugby union team. players were invited to participate in the study for the duration of the 2013 rugby season; participation was voluntary but endorsed by the management and medical staff of the team. players who volunteered to participate in the study signed informed consent. in total 19 players (mean (standard deviation (sd)) age 26 (2) years; body mass 101.5 (12.2) kg, stature 1.86 (0.07) m) volunteered. the university of johannesburg ethical review board approved the study. player grouping players were grouped according to two different classification systems, neither of which is mutually exclusive, to allow for analysis of different positional attributes. firstly, players were grouped as either forwards (props, locks, hooker, flanks and eighth man) or backs (scrumhalf, flyhalf, centres, wings and fullback). secondly, players were assigned to one of five positional groups: tight forwards (props and locks), loose forwards (hooker, flanks and eighth man), scrumhalf, inside backs (flyhalf and centres) and outside backs (wings and fullback), as previously described.[5,6] data were examined to check the validity of these groupings and were found to be accurate. procedures all matches took place between march and october 2013 during the local rugby season and were part of senior professional domestic competitions. players wore individual spi pro gps units (gpsports, australia) (mass = 76 g; size = 87 × 48 × 20 mm) positioned between the shoulder blades and supported by an elasticised harness worn underneath the playing jersey. the gps unit sampled positioning data at a frequency of 5 hz and contained a triaxial accelerometer that sampled at 100 hz. players were familiarised with the use of the gps units at practice sessions before using them in matches. the strength and conditioning coach of the team assigned and fitted the gps units on match days. there were insufficient units and harnesses for all players to wear at once, so units were rotated among players in each of the five position groups and according to the monitoring needs of the coaching staff. units were switched on before the warm-up, which started ~45 minutes before kick-off, to ensure that the satellite signal was received. sajsm vol. 27 no. 2 2015 35 after each match, the gps data files were downloaded to a personal computer and the data analysed using team ams software version 10 (gpsports, australia). the raw data files were segmented into 1st and 2nd halves, to exclude the time recorded during half time, and then exported to microsoft excel (microsoft corp, usa). 1st and 2nd half data were then combined to determine whole-game exertions. three files were excluded because players hadn’t spent a sufficient amount of time on the field (<30 minutes, which was outside 2 sds from the mean). a total of 102 match participation files from 24 separate matches were analysed in the following positional distribution: forwards (n=53), backs (n=49), tight forwards (n=23), loose forwards (n=30), scrumhalves (n=8), inside backs (n=12) and outside backs (n=29). movement and impact analysis the dependent variables for this study were total distance (m) covered, maximum speed (m.s-1) attained, distance covered in differentiated speed zones (walking, 0 2 m.s-1; jogging, 2 4 m.s-1; striding, 4 6 m.s-1; and sprinting, >6 m.s-1). these speed zones were chosen because they are typical of the locomotive activity profiles of intermittent team sport athletes.[19] data were normalised to the amount of time spent on the field to account for different playing times as a result of player substitutions. this is a departure from the subject-relative velocity measures employed by cahill et al.,[11] but allows for comparison within and between sporting codes. in addition, two broader speed zones (low-intensity running, 0 4 m.s-1 and high-intensity running, >4 m.s-1) were calculated to allow for the calculation of a high:low intensity running ratio. in addition, proportion of time spent in each speed zone was calculated. because peak velocity measurements have been shown to be more accurate than measures of distance covered at high speed,[8,13] sprint and maximal acceleration counts were included to support analysis of high-speed running distance. these are reported as frequencies (1 every n min). a sprint was defined as each time a player reached a speed >6 m.s-1, and a maximal acceleration was defined as any acceleration > 2.75m.s-2. this acceleration corresponds to a change in speed of 10 km.h-1 in a 1 second interval. accelerometer data were recorded as the total number of impacts >5g and total highintensity impacts >8g, and normalised to playing time. time on field statistics are reported to allow for calculation of total work volumes. statistical analysis data were analysed using spss version 21 (ibm, usa) analysis software. shapiro-wilk tests were performed on all dependent variables to test the assumption of normality; the majority of variables (60%) did not satisfy this assumption. data were visually assessed using normal q-q plots and were found to be similarly, and only moderately, skewed. a decision was taken to proceed with parametric tests due to the robustness of the particular tests used in dealing with deviations from normality, particularly in the presence of large sample sizes (>50) and similar sized sample groups. forwards and backs were compared using an independent samples t-test. a levene’s test was applied to the five positional groups to assess homogeneity of variance. the majority of variables were normally distributed and in these cases were assessed by one-way analysis of variance (anova) and tukey’s post hoc test. in cases where data were not normally distributed, a welch robust test for equality of means and games-howell post hoc test were applied to discern differences between groups. descriptive statistics (mean (sd)) were calculated for all variables, and the level of significance was set at p<0.05 for all tests. in addition, due to the practical nature of this study, cohen’s effect size statistic was calculated to determine the practical significance of observed differences. effect sizes (ess) of 0.2, 0.5, 0.8 and 1.2 were considered small, medium, large and very large respectively.[20] results movement analysis analysis of basic movement parameters for forwards and backs and for the five positional groups is presented in table 1. there was no significant difference in the relative distance covered during competitive match play between forwards and backs (forwards 69 (8) v. backs 69 (9) m.min-1). positional group analysis revealed that scrumhalves cover a significantly greater distance during match play than all other positional groups (81 (12) m.min-1, es 0.5 1.4). backs had greater maximum speed compared to forwards (backs 8.8 (1.1) v. forwards 7.6 (1.3) m.s-1, es 1.0). this can be accounted for by the presence of the outside backs in this group who were significantly faster (9.4 (0.9) m.s-1, es 0.4 2.2) than all other positional groups. the relative distances covered by backs and forwards in each of the four speed zones are presented in fig. 1, and a similar analysis by positional group is presented in fig. 2. forwards distinguished themselves by covering significantly more distance while walking (forwards 36 (3) v. backs 32 (5) m.min-1, es 0.9) and jogging (forwards 26 (5) v. backs 20 (5) m.min-1, es 1.3) than backline players, while backs covered twice as much distance as forwards while sprinting (backs 3.4 (2.0) v. forwards 1.4 (1.3) m.min-1, table 1. comparison of basic movement variables for forwards and backs and for the five positional groups during professional rugby union match play forwards backs movement variables, mean (sd) tight forward loose forward total scrumhalf inside back outside back total time on field (min) 72 (24) 67 (25) 69 (24) 58 (16) 82 (22) 82 (22) 78 (22) distance (m.min-1) 70 (7) 68 (8) 69 (8) 81 (12)a,b,d,e 67 (9) 67 (5) 69 (9) maximum speed (m.s-1) 7.1 (1.2) 8.0 (1.2)a 7.6 (1.3)* 8.0 (0.7) 8.0 (0.9) 9.4 (0.9)a,b,c,d 8.8 (1.1) high-intensity:low-intensity running ratio 1:13 1:5 1:8* 1:3a,b,d,e 1:5 1:4 1:4 *forwards significantly different (p<0.05) from backs. a,b,c,d,e significantly different from tight forwards, loose forwards, scrumhalf, inside backs and outside backs, respectively. 36 sajsm vol. 27 no. 2 2015 es  1.2). positional analysis revealed that loose forwards walked the least distance (31 (5)  m.min-1, es 0.6 1.2), which was significantly less than inside and outside backs. tight forwards jogged the most distance (29 (5) m.min-1, es 0.7 2.6), significantly more than loose forwards, inside and outside backs. outside backs jogged the least distance (18 (4)  m.min-1, es 0.8 2.6). there was no difference in distance covered striding between forwards and backs. scrumhalves covered the most distance (16 (5) m.min-1, es 1.4 3.2) striding, significantly more than every other group except loose forwards. the loose forwards also out performed the tight forwards and outside backs in this speed zone (11 (4) m.min-1, es  0.6 1.4). outside backs performed the most sprinting (4 (2) m.min-1, es 0.4 2.5), covering significantly more distance than tight forwards, loose forwards and inside backs in this category. tight forwards performed the least sprinting, covering just 1 (1) m.min-1 (es  .1 3.3) in this speed category. highand low-intensity running the time spent in lowand high-intensity running zones for backs and forwards is shown in fig. 3, and for positional groups in fig. 4. these results were used to calculate average high-intensity:low-intensity running ratios, which are presented in table 1. analysis revealed that forwards cover more distance than backs in low-intensity ranges (forwards 58 (7) v. backs 56 (6) m.min-1, es 0.4), while backs cover more distance in high-intensity ranges (forwards 11 (5) v. backs 14 (4) m.min-1, es 0.7). accordingly, the high-intensity:lowintensity running ratio was approximately 1:8 for forwards and 1:4 for backs. this indicates that forwards cover double the lowintensity distance for each high-intensity run than backs do. tight forwards perform the greatest amount of low-intensity running (63 (6) m.min-1, es 0.3 1.7), significantly more than loose forwards and outside backs. they also perform the least high-intensity running (7 (3) m.min-1, es 1.1 3.6), significantly less than all other position groups. tight forwards thus have the greatest high-intensity:lowintensity running ratio (1:13). scrumhalves perform the most high-intensity running (20 (5) m.min-1, es 1.2 3.6) and the second most low-intensity running (61 (8) m.min-1, es 0.3  1.0). scrumhalves have the smallest highintensity:low-intensity running ratio (1:3). proportion of time spent in speed zones the majority of playing time (79 84%) was spent walking for all positions. backs spent a significantly greater portion of time walking (forwards 80% (7%) v. backs 83% (5%), es 0.6) and sprinting (forwards 0.3% (0.3%) v. backs 0.7% (0.4%), es 1.1) than forwards did (table 2). forwards spent more time jogging than backline players (forwards 17% (6%) v. backs 13% (5%), es 0.7). tight forwards were a unique positional group, spending the most time jogging (18% (6%), es 0.5 1.0), and the least time walking (79% (7%), es 0.3 0.8) and sprinting (0.1% (0.1%), es 1.1 3.6). there was no significant difference between any position groups for time spent striding, but scrumhalves spent the most time in this speed zone (5% (1%), es 0.6 1.2). outside backs spent significantly more time sprinting (0.8% (0.4%), es 0.2 2.3) than tight and loose forwards. sprint and acceleration characteristics analysis of sprint and acceleration frequency is shown in table 3. backs reached sprint forwards backs walking jogging striding sprinting 0 10 20 30 40 36 32 26 20 9 10 1.4 3.4 * * r el at iv e d is ta n ce (m /m in ) * fig. 1. relative distances covered in four speed zones by forwards and backs. (* significant difference (p<0.05).) tight forwards loose forwards walking jogging striding sprinting 0 10r el at iv e d is ta n ce (m /m in ) 20 30 40 scrumhalves inside backs outside backs # # 1 2 3 42§ § § ### 34 31 3636 36 29 24 26 21 18 7 11 16 9 9 0 0 0 § § # # # # # fig. 2. relative distances covered in four speed zones by tight forwards, loose forwards, scrumhalves, inside backs and outside backs. (#, §, θ significant difference from tight forwards, loose forwards, scrumhalves, respectively (p<0.05).) sajsm vol. 27 no. 2 2015 37 velocity twice as often as forwards (backs 1 every 7 (14) minutes v. forwards 1 every 14 (17) minutes, es 1.1). backs also performed maximal accelerations 1.5 times more often than forwards did (backs 1 every 5 (10) minutes v. forwards 1 every 9 (13) minutes, es 1.1). notably, all players were involved in acceleration actions 30 40% more often than they were involved in sprint actions. inside and outside backs were the positions most frequently involved in both sprint and acceleration actions. tight forwards participated the least frequently in sprint and acceleration actions. impact characteristics there was no difference in the total number of impacts (backs 9.5 (3.2) v. forwards 10.0 (3.0) >5g.min-1, es 0.2) or high-intensity impacts (backs 1.1 (0.4) v. forwards 1.1 (0.5) >8g.min-1, es 0.0) between backs and forwards. inside backs experienced significantly less total impacts (6.5 (1.2) >5g. min-1, es 0.4 2.0) than tight forwards, loose forwards and outside backs. inside backs also experienced the fewest high-intensity impacts (0.7 (0.2) >8g.min-1, es 0.5 1.4). though not statistically significant, loose forwards experienced the most total (10.6 (2.3) >5g.min-1, es 0.5 2.0) and highintensity impacts (1.3 (0.7) >8g.min-1, es 0.2 1.0). discussion this analysis of the movement and impact characteristics of players participating in professional rugby union competitions is the first of its kind to be performed in sa. this research provides valuable comparison with research on players from other countries. the first major finding of this research is that there was no significant difference in the distances covered relative to time on field between forwards and backs. this result is in contrast with previous research,[3,10-12] which has reported backs covering a higher amount of relative distance than forwards. notably, these previous studies have also reported higher relative speeds for backs than the present study, while the relative distance covered by forwards was comparable. these differences may reflect differences in ball-inplay time between competitions or differences in playing style of the teams studied. a greater emphasis on forward play could lead to limited opportunities for backline players, while an increased number of kicks could increase backline player involvement. the results of the movement characteristic analysis in this study tend to agree with those that have been previously reported;[2,5,6,11] the game is played mostly at low speed with players spending the majority of their time standing, walking or jogging. notably, the forwards covered more distance in lowintensity movement zones, while backs covered more distance in high-intensity movement zones. this most likely reflects the influence of positional requirements, where forward players typically contest possession of the ball at close quarters, while backs await possession in wider areas giving them more opportunity and space in which to run.[2] positional analysis revealed that scrumhalves covered the most distance overall (81 (12) m.min-1, es 0.5 1.4) and the most distance in highintensity running zones (20 (5) m.min-1, es 1.2 3.6). these results are similar to those of cahill et al.,[11] although they reported a lower overall distance covered (median 0 10 20 30 40 50 60 r el at iv e d is ta n ce (m /m in ) forwards backs 58 56 11 14 * * low intensity high intensity 70 fig. 3. distance covered in high-intensity and low-speed zones by forwards and backs. (* significant difference (p<0.05).) low intensity high intensity 0 10 r el at iv e d is ta n ce (m /m in ) 20 30 40 50 60 tight forwards loose forwards scrumhalves inside backs outside backs # 63 55 61 57 53 0 # 0 0 # # # # 7 13 20 12 13 70 fig. 4. distance covered in high-intensity and low-speed zones by tight forwards, loose forwards, scrumhalves, inside backs and outside backs. (# and θ indicate significant difference from tight forwards and scrumhalves, respectively (p<0.05).) 38 sajsm vol. 27 no. 2 2015 78.5 m.min-1, interquartile range (iqr) 7.2). these results reflect scrumhalves’ unique role in the game where they keep pace with play in order to distribute possession, and as a result are in possession of the ball most often.[2,5,6] outside backs were the most accomplished sprinters, attaining the greatest maximum speed (9.4 (0.9) m.s-1, es 0.4 2.2), covering the most distance sprinting (4 (2) m.min-1, es 0.4 1.2) and performing sprints (1 every 6 minutes) and maximal accelerations (1 every 5 minutes) more often than other positions. outside backs also spent more time walking (84 (5)%, es 0.1 0.8) than other position groups. cahill et al.[11] also reported outside backs attaining the greatest maximum speed (median 8.8 m.s-1, iqr 0.9), and that outside backs spent the most time walking (median 51.9%, iqr 10.3). tight forwards spent more time (18 (6)%, es 0.5 1.0) and covered more distance (29 (5) m.min-1, es 0.7 2.6) jogging than any other positional group. cahill et al.[11] also reported that tight forwards spend the most time jogging (median 49.5%, iqr 7.4). in match play, tight forwards primary responsibility is in contesting and retaining possession,[2] a role that results in a great deal of physical contact in scrums, rucks and mauls. as such, tight forwards may be placed at a disadvantage when it comes to attaining high speeds, due to the highly fatiguing nature of these involvements. johnston et al.[14] have shown that physical contact reduces high-intensity running during game play, and conditioning programmes for tight forwards should reflect this. despite falling into different positional groups (backs and forwards), analysis revealed the movement characteristics of loose forwards and inside backs to be similar. there were no significant differences in distance covered jogging (loose forward 24 (4) v. inside back 21 (4) m.min-1, es 0.8), striding (loose forward 11 (4) v. inside back 9 (3) m.min-1, es 0.6) or sprinting (loose forward 2 (1) v. inside back 2 (2) m.min-1, es 0.2) for these two groups. loose forwards did walk significantly less than inside backs (loose forward 31 (5) v. inside back 36 (4) m.min-1, es 1.2). time spent in various speed zones and overall high-intensity:low-intensity running ratio table 2. comparison of proportion of time spent in the four speed zones for forwards and backs and for the five positional groups during professional rugby union match play forwards backs proportion of time in movement zones,* mean (sd) tight forward loose forward total scrumhalf inside back outside back total % time walking 79 (7)e 80 (6) 80 (7)† 80 (5) 83 (4) 84 (5) 83 (5) % time jogging 18 (6)d,e 15 (5) 17 (6)† 14 (5) 12 (4) 13 (5) 13 (5) % time striding 3 (4) 4 (1) 3 (3) 5 (1) 4 (3) 3 (1) 4 (2) % time sprinting 0.1 (0.1)b,c,e 0.5 (0.3)e 0.3 (0.3)† 0.7 (0.3) 0.5 (0.5) 0.8 (0.4) 0.7 (0.4) *the total proportion time for each position group is 100%; discrepancies are due to rounding where it was felt that percentage fractions were only relevant in the % time sprinting zone. †indicates forwards significantly different (p<0.05) from backs. a,b,c,d,e indicates significantly different from tight forwards, loose forwards, scrumhalf, inside backs and outside backs, respectively. table 3. comparison of sprint and maximal acceleration frequency for forwards and backs and the five positional groups forwards backs sprint variables, mean (sd) tight forward loose forward total scrumhalf inside back outside back total sprint per min (>6 m.s-1) 1 every 33 (33) minb,e 1 every 10 (17) min 1 every 14 (17) min* 1 every 7 (14) min 1 every 9 (11) min 1 every 6 (14) min 1 every 7 (14) min accelerations per min (>2.75 m.s-2) 1 every 14 (25) mine 1 every 7 (13) min 1 every 9 (13) min* 1 every 4 (14) min 1 every 7 (9) min 1 every 5 (11) min 1 every 5 (10) min *indicates forwards significantly different (p<0.05) from backs. a,b,c,d,e indicates significantly different from tight forwards, loose forwards, scrumhalf, inside backs and outside backs, respectively. table 4. comparison of total impact and high-intensity impact frequency for forwards and backs, and for five positional groups forwards backs impact variables, mean (sd) tight forward loose forward total scrumhalf inside back outside back total impacts (>5g.min-1) 9.6 (3.4) 10.6 (2.3) 10.0 (3.0) 9.4 (3.2) 6.5 (1.2)a,b,e 10.9 (2.9) 9.5 (3.2) high-intensity impacts (>8g.min-1) 0.9 (0.4) 1.3 (0.7) 1.1 (0.5) 0.9 (0.3) 0.7 (0.2)e 1.2 (0.4) 1.1 (0.4) *indicates forwards significantly different (p<0.05) from backs. a,b,c,d,e indicates significantly different from tight forwards, loose forwards, scrumhalf, inside backs and outside backs, respectively. sajsm vol. 27 no. 2 2015 39 was the same for loose forwards and inside backs. these results indicate that the typical strategy of grouping forwards and backs during training is most likely wrong. it may be more prudent to group tight forwards, loose forwards and inside backs, scrumhalves, and outside backs for training. scrumhalves have highly unique positional requirements and should have specialised programmes that reflect this. analysis of accelerometer data revealed that there was no difference in the number of total (backs 9.5 (3.2) v. forwards 10.0 (3.0) >5g.min-1, es 0.1) or high-intensity impacts (backs 1.1 (0.4) v. forwards 1.1 (0.5) >8g.min-1, es 0.0) between backs and forwards. it was notable however that loose forwards (1.3 (0.7) >8g.min-1, es  0.2 1.0) and outside backs (1.2 (0.4) >8g.min-1, es 0.2 1.4) were the positions most likely to be involved in high-intensity impacts. these results may reflect the greater speeds that outside backs are capable of, resulting in a preponderance of high-speed collisions. forwards are typically involved in a higher number of tackles and rucks than other positions,[2] which may result in a greater number of highintensity impacts. accelerometer measures have been shown to be reasonably reliable,[15] while validity of these measures is still to be established. they are reported here to provide normative data for practitioners using these gps devices. overall, the results of this research tend to agree with those of cahill et al.’s[11] research into english premiership rugby teams. a notable exception to this is the difference in relative distance covered by backs and forwards found by cahill et al.[11], which was not found here. further comparisons between the two studies are impeded by differences in methodology of measurement. cahill et al.[11] chose to use subject relative speed bands based on percentages of each player’s observed maximum speed during match play. our study chose to use objective speed criteria. generally, the proportion of distance covered and time spent in each speed zone was similar for the two studies, but cahill et al.[11] reported greater absolute values. the authors would speculate that these absolute differences are as a result of differences in ball in play time, but further research is required. study limitation a limitation of this study was that it only examined one team, with multiple measures performed on the same players. cahill et al.[11] were able to collect data from eight different teams. as a result of this, some of the results reflected here will be accounted for by team tactics and prevailing playing conditions. there is scope to extend this type of analysis to more teams and to include measurements of static work such as scrumming and lifting that is not revealed by gps analysis. conclusion this investigation has highlighted the variation in movement patterns in professional rugby union players playing in different positions. coaches and strength and conditioning programme designers should be aware of these variations when planning. training programmes should as far as possible be specialised and reflect the running intensities and frequencies of sprints and acceleration that are present for each positional group during match play. acknowledgements. the players and coaching staff of the golden lions rugby union are thanked for their cooperation in this research project. this project was partially funded by the national research foundation, and thanks go to them for their continued support. references 1. duthie g, pyne d, hooper s. applied physiology and game analysis of rugby union. sports med 2003;33(13):973-991. 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[http://dx.doi.org/10.1007/s40279-013-0069-2] 10. coughlan gf, green bs, pook pt, toolan e, o’connor sp. physical game demands in elite rugby union: a global positioning system analysis and possible implications for rehabilitation. j orthop sports phys ther 2011;41(8):600-605. [http://dx.doi. org/10.2519/jospt.2011.3508] 11. cahill n, lamb k, worsfold p, headey r, murray s. the movement characteristics of english premiership rugby union players. j sports sci 2013;31(3):229-237. [http:// dx.doi.org/10.1080/02640414.2012.727456] 12. reid lc, cowman jr, green bs, coughlan gf. return to play in elite rugby union: application of global positioning system technology in return-to-running programs. j sport rehabil 2013;22(2):122-129. 13. petersen c, pyne d, portus m, dawson b. validity and reliability of gps units to monitor cricket-specific movement patterns. int j sports physiol perform 2009;4(3):381-393. 14. johnston rd, gabbett tj, seibold aj, jenkins dg. influence of physical contact on pacing strategies during game-based activities. int j sports physiol perform 2014;9(5):811-816. [http://dx.doi.org/10.1123/ijspp.2013-0424] 15. waldron m, worsfold p, twist c, lamb k. concurrent validity and test-retest reliability of a global positioning system (gps) and timing gates to assess sprint performance variables. j sports sci 2011;29(15):1613-1619. [http://dx.doi.org/10.10 80/02640414.2011.608703] 16. mclellan cp, lovell di. neuromuscular responses to impact and collision during elite rugby league match play. j strength cond res 2012;26(5):1431-40. [http://dx.doi. org/10.1519/jsc.0b013e318231a627] 17. mclellan cp, lovell di, gass gc. performance analysis of elite rugby league match play using global positioning systems. j strength cond res 2011;25(6):1703-1710. [http://dx.doi.org/10.1519/jsc.0b013e3181ddf678] 18. international rugby board. irb game analysis reports 2011. dublin: international rugby board, 2011. http://www.irbplayerwelfare.com/?documentid=76 (accessed 13 november 2014). 19. dwyer db, gabbett tj. global positioning system data analysis: velocity ranges and a new definition of sprinting for field sport athletes. j strength cond res 2012;26(3):818824. [http://dx.doi.org/10.1519/jsc.0b013e3182276555] 20. hopkins wg, marshall sw, batterham am, hanin j. progressive statistics for studies in sports medicine and exercise science. med sci sports exerc. 2009;41(1):3-13. [http://dx.doi.org/10.1249/mss.0b013e31818cb278] introduction qualitative, in the context of research, refers to ‘quality in the sense of hallmarks, features, character, nuances, complexity, or nature of the phenomenon under study’. 1 qualitative research methods are the strategies used in the process of collecting, organising and interpreting text obtained through observation, or from communication with individuals or groups. 1 qualitative research is used most commonly in the social sciences, such as psychology, sociology and social anthropology, and qualitative research methods are also used frequently in market research. however, the qualitative approach and qualitative methods are now being used more frequently in health sciences research, a field in which the ‘hard sciences’ and statistics have traditionally dominated. the purpose of this article is to clarify the role of qualitative research in exercise science and sports medicine and provide the reader with a basic understanding of qualitative research. where qualitative research is used in exercise science and sports medicine within the fields of exercise science and sports medicine, qualitative research methods are being included more frequently in studies designed to evaluate programmes. for example, programmes that need to be evaluated may have a health promotion focus, such as schooland community-based programmes promoting physical activity, or may be sport related, such as a life skills programme for elite athletes. in programme evaluation qualitative research methods are particularly helpful when evaluating less tangible outcomes that are difficult to quantify, e.g. an evaluation of the participants’ experiences of the programme. if these methods are properly implemented they can provide valuable insight into factors contributing to success and/ or failure of programmes, including both individual and contextual factors, as well as the strengths and weakness of a programme. sometimes studies in exercise science and sports medicine require measurement of behavioural perspectives such as an understanding of individuals’ motivations, attitudes, beliefs and perceptions. these factors are difficult to assess without using qualitative research methods. qualitative methods are also becoming increasingly useful in the investigation of contextual factors that impact on physical activity and sporting performance. collecting qualitative data the main methods of collecting qualitative data are in-depth interviews, focus groups, observation and open-ended questions in questionnaires. an open-ended question requires a response from the participant rather than merely choosing an option from a provided list of options. in-depth interviews can be described as conversations between an interviewer and interviewee, where the interviewer’s main role is to listen carefully to the interviewee and frame questions around the interviewee’s responses. in this context the interviewee is not so much a subject under examination, but more a partner, having an active role in directing the interview discussion and bringing the interviewer to a point of understanding his or her unique perspective. in-depth interviews are generally structured around relatively general, open-ended guide questions. 2 interviews are most useful in studies where it is likely that there will be a range of individual perspectives and experiences. key informant interviews are a type of in-depth interviews. key informants are defined as individuals who are knowledgeable in a particular area, or who hold special status or skills. these types of informants are able to share their knowledge and skills, as well as their unique perspectives, observations and insights to which the commentary role of qualitative research in exercise science and sports medicine abstract qualitative research is featuring more frequently in health sciences research, a field in which the ‘hard sciences’ and statistics have traditionally dominated. for example, within the fields of exercise science and sports medicine, qualitative research methods are included to evaluate intervention programmes. these methods are also being used in studies that require measurement of behavioural perspectives, such as an understanding of individuals’ motivations, attitudes, beliefs and perceptions. qualitative research methods are also becoming increasingly useful in the investigation of contextual factors that impact on physical activity and sporting performance. the purpose of this article is to clarify the role of qualitative research in exercise science and sports medicine and provide the reader with a basic understanding of the basis of qualitative research. qualitative data collection and analysis, sampling strategies in qualitative research, the role of the qualitative researcher, and issues of scientific rigour regarding qualitative research will be addressed. correspondence: catherine e draper uct/mrc research unit for exercise science and sports medicine sports science institute of south africa boundary road newlands 7700 cape town, south africa tel: 27-21-650-4567 fax: 27-21-686-7530 e-mail: catherine.draper@uct.ac.za catherine e draper (ma, phd) uct/mrc research unit for exercise science and sports medicine, sports science institute of south africa, cape town sajsm vol 21 no. 1 2009 27 researcher would otherwise not have access; these help to enrich the understanding of the researcher. 3 a focus group can be defined as a group of individuals, usually no more than 8, who are guided by a group facilitator to engage in a relatively informal discussion that is centred around a specific issue or topic. 4 the facilitator’s role is to pose questions to the group, just as in an in-depth interview, to generate discussion and encourage group members to participate and interact with one another, 4 as well as to listen carefully and learn from the members of the group. 5 focus groups are most useful in studies where it is likely that individuals will share common views or common experiences, such as being in a team together, or participating in the same programme. purposive sampling and role of the researcher one of the foundational aspects of qualitative research is that it aims for information richness 6 and the understanding of social processes. 7 this distinguishes it from quantitative research, which aims for generalisability. therefore, qualitative research requires a different strategy for sampling research participants – purposive sampling. purposive sampling is a type of sampling that selects specific individuals or groups because they match criteria that are necessary for the investigation of whatever is being studied. this approach to sampling allows the researcher to explore particular issues relevant to the research, as well as to include particular key informants who can offer important and distinctive knowledge to the researcher. 3,7 it should however be noted that in qualitative research, even though samples are not randomised, they should represent a range of individuals that would present the diverse views within the population under investigation. in contrast to quantitative researchers, qualitative researchers are seen as research instruments, 3,7-9 as they become part of the research process. 9 therefore, it is highly unlikely that the researcher will be able to take on a completely neutral or objective stance in this process. 8 the qualitative approach holds that the relationship between the researcher and research process should be considered and revealed throughout the process, and that in acknowledging this relationship, bias is not eliminated, but is accounted for. 3,10 this influence of the researcher (his/her background, characteristics and position) on the research process is termed ‘reflexivity’, and is accepted as part of the methodology in qualitative research. qualitative researchers are indeed encouraged to acknowledge its presence. 3,8,10 qualitative data analysis perhaps the most daunting aspect of qualitative research is qualitative data analysis. in essence, the analysis of qualitative data has similarities to statistical analysis of quantitative data, as it also involves a process of coding and categorising data. qualitative data analysis is essentially a process of data reduction in which the researcher selects, focuses, simplifies and categorises data, thereby dividing it into more manageable pieces so that the researcher can interpret the data. 9 this process may be inductive, if patterns, themes and categories are derived from the data itself, or deductive, if categories are introduced either at the start of, or part of the way through the analysis, and data are analysed according to this framework. 3 in terms of the actual process of qualitative data analysis, guidelines and conventions exist that can assist researchers in this process. 3 the method of analysis should be verifiable and carried out systematically, 11 which often makes it time consuming. however, there are computer programmes that have been designed to reduce the time of coding and categorising, although these programmes still require the researcher to do the thinking and to guide the analysis. ‘soft’ science? the main criticism of qualitative research is that it lacks scientific rigour, specifically around issues of validity (i.e. are research findings credible?), reliability (i.e. do research instruments measure what they are supposed to measure?), reproducibility (i.e. can the research be repeated?), and generalisability (i.e. can the findings from a sample be extrapolated to the rest of the population from which the sample is taken?). however, good qualitative researchers will argue that this is not the case and that validity is upheld using multiple research methods called triangulation. 7,8 apart from methodological triangulation, data triangulation can be employed, which uses data from different sources, and possibly from different settings, at different points in time. 8 investigator triangulation involves a team of researchers, and theory triangulation can be adopted where researchers compare the data to a number of hypotheses. 12 triangulation can also refer to the use of qualitative and quantitative methods in the same study, and underlying this is the understanding that quantitative and qualitative research should not compete for superiority, but rather complement each other. summary there are ways in which good qualitative researchers address issues of rigour, and ultimately produce information that can be reported and applied outside of the research setting. this rests on the understanding that qualitative research methods form part of a systematic and reflective process that develops knowledge that can be shared and challenged. 10 it may be said that quantitative research answers the important questions of ‘who?’, ‘what?’, ‘where?’, and ‘when?’ , and qualitative research contributes by helping to answer the ‘why?’ questions. within the field of exercise science and sports medicine, there is not only a plethora of ‘why?’ questions that need answering, but also a vast array of issues and phenomena that are difficult, if not impossible, to quantify. thus, quantitative data can provide a framework or skeleton for understanding something, and qualitative data can fill in the gaps and provide the ‘flesh’. references 1. malterud k. the art and science of clinical knowledge: evidence beyond measures and numbers. lancet 2001;358:397-400. 2. rubin hj, rubin is. qualitative interviewing: the art of hearing data. thousand oaks, calif.: sage; 1995. 3. patton mq. qualitative research and evaluation methods. 3rd ed. thousand oaks, calif.: sage; 2002. 4. wilkinson s. focus group research. in: silverman d, ed. qualitative research: theory, method and practice. london: sage; 1997. p. 177-199. 5. morgan dl. the focus group guidebook. the focus group kit, vol. 1. thousand oaks, calif.: sage; 1998. 6. kuzel aj. sampling in qualitative inquiry. in: crabtree bf, miller wl, eds. doing qualitative research. thousand oaks, calif.: sage, 1992; p.31-44. 7. mays n, pope c. rigour and qualitative research. bmj 1995;311:109112. 8. flick u. an introduction to qualitative research. london: sage; 1998. 9. marshall c, rossman gb. designing qualitative research. 2nd ed. thousand oaks, calif.: sage; 1995. 10. malterud k. qualitative research: standards, challenges, and guidelines. lancet 2001;358:483-488. 11. krueger ra. analyzing and reporting focus group results. the focus group kit, vol. 6. thousand oaks, calif.: sage; p. 1998. 12. seale c. the quality of qualitative research. london: sage; 1999. 28 sajsm vol 21 no. 1 2009 sajsm 595 (commentarty).indd position statement 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license implications of covid-19 for resumption of sport in south africa: a south african sports medicine association (sasma) position statement – part 2 da ramagole,1 mbchb, msc; dc janse van rensburg,1,2 mmed, md; l pillay,1 mbchb, msc; p viviers,3,4,5 mbchb, mmedsc; p zondi,6,7 mbchb, msc, j patricios,8 mbbch ffsem(uk) 1 section sports medicine & sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa 2 medical board member, international netball federation, manchester, uk 3 campus health service, stellenbosch university, south africa 4 institute of sport and exercise medicine, division of orthopaedic surgery, department of surgical sciences, faculty of medicine and health sciences, stellenbosch university, south africa 5 fifa medical centre of excellence, south africa 6 sports science institute of south africa, newlands, south africa 7 south african sports confederation and olympic committee, medical advisory committee 8 wits sport and health (wish), faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: da ramagole (maki.ramagole@up.ac.za) the intense scientific focus and medical scrutiny on the severe acute respiratory syndrome coronavirus 2 (sars-cov-2) pathogen and covid-19 disease have resulted in an exponential increase in evidence-based publications, case studies and reviews.[1,2] this has necessitated regular reappraisal of scientific evidence and best practice recommendations. this paper represents the first reassessment by sasma, and further updates will be forthcoming as new evidence emerges. the lockdown rules were relaxed to level 2 from midnight on 17 august 2020, allowing for more movement and training in small groups without spectators, but with concomitant stringent measures to reduce the spread of sars-cov-2 infections. these measures included regular hand washing, respiratory etiquette, the wearing of masks, and the maintenance of physical (social) distancing. on 16 september 2020, president cyril ramaphosa announced that south africa would further ease restrictions and enter into level 1 lockdown. at the time of the submission of this update, the level 1 regulations and their impact on sport had not yet been gazetted. the purpose of this document is to highlight areas in which there have been developments that may influence the management of athletes returning to sport amidst the ongoing covid-19 pandemic. it is not a detailed clinical review of covid-19 and should be used as supplementary material to inform decision-making. in this document updates in the following clinical areas are provided: ● clinical manifestations and multi-organ involvement ● testing for sars-cov-2 ● prolonged positive real-time polymerase chain reaction (rtpcr) and the role of quantitative real-time polymerase chain reaction (rt-qpcr) in informing return to sports (rtp) ● grading of disease severity, individualised management of infected athletes and graduated return to play guidelines (grtp) ● other considerations: o athletes with disabilities o immunisation o the use of masks during exercise o biologically safe environments (bse) ● sasma guidelines for safe rtp in level 1 lockdown during sars-cov-2 clinical manifestations of illness covid-19 is known for the initial pulmonary manifestations, but research has shown extensive extra-pulmonary involvement including cardiac abnormalities, hepatocellular damage, ocular problems, dermatological manifestations, renal complications, and neurologic problems, amongst others. common extra-pulmonary manifestations of covid-19 include ophthalmic complications, such as conjunctivitis, conjunctival congestion and retinal involvement in some cases.[3] there are also accompanying deficits in both muscle strength and endurance, likely due to the pro-inflammatory effects of the viral infection and the deconditioning that occurs during the convalescent period. [4] the infographic below (fig. 1) shows the multi-organ manifestation of the illness. this multi-organ involvement can be detrimental to athletes the lockdown regulations due to the coronavirus pandemic (covid-19) that broke out towards the end of 2019 and continued to spread throughout most countries in the world had a negative effect on the sporting community. the south african government eased the lockdown rules to level 1 from 21 september 2020. in part 2 of this position statement of the south african sports medicine association (sasma), the authors address the position regarding the safe return to sports for athletes who were infected by the virus. an update on clinical manifestations and multi-organ involvement, testing for severe acute respiratory syndrome coronavirus 2 (sars-cov-2), prolonged positive real time polymerase chain reaction (rtpcr) and the role of quantitative real time polymerase chain reaction (rt-qpcr) in informing return to sports, grading of disease severity, individualised management of infected athletes and graduated return to play guidelines (grtp) is provided. the authors also share thoughts on athletes with disabilities, immunisation, the using of masks during exercise and utilising biologically safe environments (bse). finally the sasma guidelines for safe rtp in level 1 lockdown during sars-cov-2 are introduced. keywords: athlete, prolonged positive test, manifestation s afr j sports med 2020; 32:1-5. doi: 10.17159/2078-516x/2020/v32i1a8986 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8986 https://orcid.org/0000-0001-6682-3438 https://orcid.org/0000-0002-5341-6080 https://orcid.org/0000-0002-8353-3376 https://orcid.org/0000-0003-1058-6992 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0001-6001-5966 position statement sajsm vol. 32 no. 1 2020 2 leading to prolonged illness and a delay in the return to their prior level of performance. multi-organ involvement may manifest despite a relatively benign initial covid-19 presentation and be disclosed by means of exertion. athletes with prolonged illnesses or those who are struggling to progress through a grtp programme must be investigated for extra-pulmonary complications. return to play guidelines should be adapted to accommodate for adequate management of any complications and allow for full recovery before the resumption of vigorous activity. the impact of the pandemic on individual and societal mental wellbeing has been particularly significant. it has also been noted that this pandemic has affected the livelihood of people including healthcare workers regarding issues on income and uncertainties about job security. this can precipitate depression, anxiety, insomnia and other mental health issues in certain individuals.[5] it is therefore recommended that mental health assessments should be part of the holistic approach in the management of this ailment. testing for sars-cov-2 a positive diagnosis is confirmed by the presence of viral rna detected by rt-pcr testing. although this test has typically been conducted on secretions obtained from either a nasopharyngeal or oropharyngeal swab, a recent study has shown that detection of the virus in saliva has a similar sensitivity. in countries where saliva tests are available, individuals who suspect infection or exposure can selfadminister the test, decreasing the burden on testing laboratories, and decreasing the risk of transmitting illness to healthcare workers administering tests. [6] prolonged positive tests in athletes part 1 of the sasma position statement outlines guidelines for monitoring and clinical evaluation, including referral for further cardiology and respiratory investigations.[7] a particular quandary for medical staff relates to prolonged positive tests in athletes who have recovered from illness, are asymptomatic, and are otherwise ready to return to training. a study by carmo et al. suggests that some patients may present with prolonged positive rt-pcr tests after sars-cov-2 infection due to a slower immune response although this has not been associated with severe disease.[8] prolonged positive tests have also been reported in healthcare workers, and this may be attributed to persistent shedding of the virus.[9] in asymptomatic patients with prolonged positive test results, the rt-qpcr, which confirms the quantity of the virus in a swab, offers the potential to assist in deciding whether patients are still infectious or if the amount of the virus detected is meaningful. this is done by reporting the cycle threshold (ct) value, which is inversely proportional to the viral load. emerging research shows that patients with a ct value above 35 do not excre te infectious viral particles and can therefore be de-isolated.[10] further evidence suggests that an increase of approximately 3.3 in ct value equates to a tenfold decr ease in the viral load. used in conjunction with other investigations and a clinical assessment, the ct value may be a helpful tool to inform decisions on rtp in athletes with prolonged positive tests. immunoglobulins detected in serological analysis may be another clinically useful indicator. the presence of immunoglobulin m and g (igm and igg) antibodies can be used to monitor the progression of the disease. igm antibodies are produced early in the infection stage and decline with time, while igg antibodies persist for up to 16 months in previously known sars infections.[1] the presence of igg and low or absent igm can therefore be used as an indicator of past inactive infection. [11] grading of illness severity the canadian olympic and paralympic working committee has published clinical guidelines grading covid -19 into three levels of infection that need to be managed differently: [12] 1. covid-19 positive and asymptomatic. these athletes have mild disease and symptom resolution within 10 days. 2. covid-19 positive and prolonged course. these athletes have regional or systemic symptoms lasting more than 10 fig. 1. extra-pulmonary manifestations of covid-19. (infographic designed by university of pretoria, creative studios, marizanne booyens © 2020) position statement 3 sajsm vol. 32 no. 1 2020 days, or severe symptoms that may require hospitalisation. 3. covid-19 positive with symptoms developing during graduated return to play progression (grtpp). according to these guidelines, individualised management of affected athletes is important and can be stratified as follows: 1. covid-19 positive and asymptomatic or mild localised disease ● self-isolation ● rest and recovery (no exercise) ● de-isolation after 10 days ● a careful history and clinical evaluation by a physician ● based on clinical assessment, and in the presence of preexisting comorbidities, consider blood troponin levels and 12-lead resting electrocardiograph (ecg), inflammatory markers, e.g. creactive protein (crp), full blood count (fbc), troponin, renal assessment and spirometry ● in the absence of comorbidities, athletes may begin a grtpp if they are symptom-free and have not been on any medication for seven days 2. covid-19 positive with prolonged course ● self-isolation ● rest and recovery (no exercise) ● when asymptomatic, full history and medical assessment are required including: o fbc, crp, troponin, creatinine o ecg, echocardiogram o spirometry ● athletes with an abnormal cardiac evaluation should be referred to a cardiologist. the assessment may include effort ecg, echo and cardiac magnetic resonance imaging (mri). ● those with an abnormal spirometry should be referred to a pulmonologist. ● those with no evidence of cardiac or pulmonary involvement can start the grtpp after seven days of being symptom-free and as long as they are not on medication for covid-19-related symptoms. fig. 2. covid-19 graduated return to play for performance athletes: guidance for medical professionals (permission to reuse granted by bmj publishing, bjsm, english institute of sport and sport scotland institute of sport; 03 oct 2020) position statement sajsm vol. 32 no. 1 2020 4 3. the third group is athletes who were covid-19 positive and developed symptoms during the grtpp. these athletes may present with the following symptoms during training: ● elevated resting heart rate ● elevated heart rate at submaximal exertion ● increased shortness of breath (sob) during exertion or increased rating of perceived exertion (rpe) these athletes should not exercise and continue with rest while symptoms persist. they will need re-evaluation and should be assessed by a sports cardiologist who may refer the athlete for a stress ecg and cardiac mri to exclude cardiac oedema[13] before resumption of the grtpp. fig. 2 by elliot et al. [14] gives an example of a grtpp introduced after covid-19 infection. importantly, the grtpp must be done under medical supervision. other considerations athletes with disabilities when planning to resume sport and physical activities, athletes with disabilities should receive extra considerations and precautionary measures. these athletes remain at a higher risk for more severe forms of illness, and considerations for different types of disabilities need to be put in place.[15] custodians of disability sport will need to customise rtp where clinically relevant. immunisation immunisation, as the fastest means of achieving herd immunity, presents the most promising way of returning to sport in a normalised environment. several vaccines are being developed by a number of pharmaceutical companies globally. lurie et al. describe the types of vaccines and different approaches being trialled, specifically: live attenuated, inactivated, replicating or non-replicating viruses, with varying use of dna, rna or protein subunits to develop the vaccine.[16] global collaboration towards developing a vaccine against the sars-cov-2 virus has enabled rapid progress with clinical phase 3 trials underway in the uk, america, brazil and south africa.[17] views on the wearing of masks during exercise the wearing face masks is one of the key strategies to minimise infection. careful consideration should be given to the type of masks used, factoring in comfort, hygiene, level of exertion and underlying comorbidities.[18] cloth masks are generally recommended for exercise as they are easier to breathe through and to keep clean by regular washing.[19] sasma’s position on mask-wearing, particularly where the athletes have not had a recent negative covid-19 pcr test, is stated below: ● masks should be worn by all athletes to and from training and matches, as well as in the changeroom ● where exercise is performed at low to moderate intensities and masks can be tolerated, they should be worn. at high intensities of exercise, where breathing difficulties may occur, athletes may exercise without masks but should attempt to increase physical distancing to a minimum of five m for runners and up to 10 m for cyclists as per a simulation study done by blocken et al.[20] this study also advises on maintaining physical distancing of 1.5 m apart for people who are stationary, and the distance increased to 5-10 m depending on the level of exertion when exercising with a mask is not possible biologically safe environments the premier soccer league (psl) in south africa has implemented bringing teams back in a biologically safe environment (bse) or “bubble”. the bse was achieved in a phased manner. this could only be done once the government approved the application for resumption of training and matches behind closed doors. this phased approach is added as a supplementary document: annexure 1. sasma guidelines for safe rtp in level 1 lockdown during covid-19 and sars-cov-2: ● thorough pre-participation medical and physical screening ● follow guidelines on grtpp for infected athletes ● persistent positive test – request rt-qpcr. this will indicate ct values, and values over 35 are considered less meaningful and unlikely to be infectious ● stringent hand hygiene and avoidance of face touching ● wearing of masks ● frequent cleaning of all equipment ● social distancing at 1.5 m apart for stationary people, and distance increased to 5-10 m depending on the level of exertion without a mask ● sports with no spectators (as per current government guidelines) ● limitation of travelling according to government guidelines conclusion in the absence of herd immunity, covid-19 remains a public health risk in south africa and globally. although encouraged by the declining number of positive tests, everyone should remain vigilant and responsible during the ongoing pandemic. as athletes prepare to return to sport, this must be done cautiously with collaboration between medical and coaching staff. athletes must be cleared to participate after an infection and be gradually assisted to good health and performance. sasma reminds all stakeholders to continue with hand hygiene, respiratory etiquette, physical distancing and importantly, all south africans are encouraged to keep active and healthy during this period. conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. no research ethical approval was needed. approved by: south african sports medicine association (sasma) executive committee author contributions: drafting the paper: da ramagole, dc janse van rensburg, l pillay. content review: p viviers, p zondi, j patricios. references 1. tom mr, mina mj. to interpret the sars-cov-2 test, consider the cycle threshold value. clin infect dis 2020; ciaa619. [doi: 10.1093/cid/ciaa619][pmid: 32435816] 2. hull jh, loosemore m, schwellnus m. respiratory health in athletes: facing the covid-19 challenge. lancet respir med position statement 5 sajsm vol. 32 no. 1 2020 2020;8(6):557-558. [doi: 10.1016/s2213-2600(20)30175-2] [pmid: 32277869] 3. gupta a, madhavan mv, sehgal k, et al. extrapulmonary manifestations of covid-19. nat med 2020;26(7):1017-1032. [doi: 10.1038/s41591-020-0968-3][pmid: 32651579] 4. disser np, de micheli aj, schonk mm, et al. musculoskeletal consequences of covid-19. j bone joint surg am 2020;102(14):1197-1204. [doi: 10.2106/jbjs.20.00847] 5. rajkumar rp. covid-19 and mental health: a review of the existing literature. asian j psychiatr 2020:102066. [doi: 10.1016/j.ajp.2020.102066][pmid: 32302935] 6. wyllie al, fournier j, casanovas-massana a, et al. saliva or nasopharyngeal swab specimens for detection of sars-cov-2. n engl j med 2020;383: 1283-1286. [doi: 10.1056/nejmc2016359] 7. ramagole d, janse van rensburg dc, pillay l, et al. implications of covid-19 for resumption of sport in south africa: a south african sports medicine association (sasma) position statement. s afr j sports med 2020;32(1):1-6. [doi:10.17159/2078516x/2020/v32i1a8454] 8. carmo a, pereira-vaz j, mota v, et al. clearance and persistence of sars-cov-2 rna in patients with covid-19. j med virol 2020;10.1002/jmv.26.26103. [doi:10.1002/ jmv.26103][pmid: 32484958] 9. gombar s, chang m, hogan ca, et al. persistent detection of sars-cov-2 rna in patients and healthcare workers with covid-19. j clin virol 2020:104477. [doi: 10.1016/ j.jcv.2020.104477][pmid: 32505778] 10. la scola b, le bideau m, andreani j, et al. viral rna load as determined by cell culture as a management tool for discharge of sars-cov-2 patients from infectious disease wards. eur j clin microbiol infect dis 2020;39(6):1059-1061. [doi:10.1007/s10096020-03913-9][pmid:322342252] 11. bretscher pa. on the control between cell-mediated, igm and igg immunity. cell immunol 1974;13(2):171-195. [doi:10.1016/0008-8749(74)90237-8] 12. return to health and performance following covid-19 infection: a guideline endorsed by the canadian sport institute (csi) chief medical officers (cmos) canadian olympic committee (coc) cmo et al. version 1: july 27, 2020: 6p. 13. wilson mg, hull jh, rogers j, et al. cardiorespiratory considerations for return-to-play in elite athletes after covid-19 infection: a practical guide for sport and exercise medicine physicians. br j sports med 2020;54: 1157-1161. [doi: 10.1136/bjsports-2020-102710] 14. elliott n, martin r, heron n, et al. infographic. graduated return to play guidance following covid-19 infection. br j sports med 2020;bjsports-2020-102637. [doi:10.1136/bjsports-2020-102637] [pmid: 32571796] 15. dantas mj, dantas tl, júnior jd, et al. covid-19: considerations for the disabled athlete. revista brasileira de fisiologia do exercício 2020;19(2):30-34. [doi:10.33233/ rbfe.v19i2.4023] 16. lurie n, saville m, hatchett r, et al. developing covid-19 vaccines at pandemic speed. n engl j med 2020;382(21):19691973. [doi:10.1056/nejmp2005630][pmid: 32227757] 17. mahase e. covid-19: oxford team begins vaccine trials in brazil and south africa to determine efficacy. bmj; 2020; 369: m2612. [doi: 10.1136/bmj.m2612][pmid: 32601063] 18. epstein d, korytny a, isenberg y, et al. return to training in the covid-19 era: the physiological effects of face masks during exercise. scand j med sci sports 2020; 00: 1-6. [doi: 10.1111/sms.13832] 19. janse van rensburg dc, pillay l, hendricks s,. year of the face mask: do's and dont's during exercise. s afr j sports med 2020;32(1):1-2. [doi: 10.17159/2078-516x/2020/v32i1a8615] 20. blocken b, malizia f, van druenen t, et al. towards aerodynamically equivalent covid19 1.5 m social distancing for walking and running. available at: http://www.urbanphysics.net/social%20distancing%20v20_wh ite_paper.pdf. 2020; 12p. 94 sajsm vol 18 no.1 2006 despite the proliferation of new specialist journals it is becoming increasingly difficult to get research work published. there are a number of reasons for this – perhaps the most obvious is that there are more institutions which specialise in sports medicine and exercise science now than there were 10 years ago. therefore the volume of research has increased precipitously. this means the standard of the journals can be kept at a reasonably high level because there is always a surplus of papers which are submitted for consideration. just as the other journals are raising the bar for the quality of the papers they publish, so is the south african journal of sports medicine doing likewise. this has enabled us to refine our niche area and focus on those papers which are relevant to sports medicine and exercise science in south africa. coupled to this we have also become stricter about publishing research which attempts to determine ‘ethnic differences’ without controlling or accounting for factors such as nutritional status, level of physical activity and socio-economic status between the groups. failing to do this makes the conclusions of any differences in ethnicity irrelevant and incorrect. researchers who use ethnicity as a variable are encouraged to read the excellent article ‘racial profiling in medical research: what are we measuring?’. 1 the south african journal of sports medicine rejects about 50% of the papers submitted because they are either not formatted correctly or do not have a clearly outlined question. another reason for rejecting papers is that the discussion on the data does not devote sufficient attention to the actual data in the study. in an attempt to assist in increasing the ‘hit rate’ of papers getting accepted i thought i would highlight a few simple points which are linked to the ultimate success of the paper getting published. firstly the introduction – this is probably the most difficult section to write as this is the section of the paper that captures the interest of the reader. a well-written introduction should provide sufficient background about why the study was done, and then should explain very clearly the research question. if the introduction is lacking in any of these features, it makes it difficult for the rest of the paper to prove to the reader that the study is worthwhile. next the methods have to be described in sufficient detail so that, if needs be, someone else can repeat the study with the same degree of accuracy. the authors need to find a balance between citing previously published methods and using an original description of the methodology. the next important section is the results section. the creative ability of the researchers comes to the fore in this section as the data need to be displayed clearly and accurately. the authors have to find a balance between presenting the data in the text, figures and tables. figures should be clearly drawn with clearly labelled axes and legends with sufficient detail to enable the figure and legend to ‘stand alone’. several authors make the mistake of discussing their findings in the results section. this is not acceptable and any paper with any discussion in the results section will be sent back for reformatting. the statistics used to analyse the data must be presented clearly. if the author(s) is/are not proficient in statistics then they are encouraged to consult a statistician who can assist in ensuring that the statistics are relevant and applied correctly. in many types of research in exercise science and sports medicine the researchers need to go beyond just presenting their data as being significant, or not, at the 5% level. considering elite performance, in many cases an improvement of 0.5% is regarded as meaningful, yet it will be almost impossible to ever show that this is statistically significant. there are other creative procedures, such as effects sizes and magnitude of differences which allow the data to be interpreted in a more meaningful way. the last section of the paper is the discussion. a good discussion finds a balance between unfolding and interpreting the main findings in the study and relating these findings to other published research, where possible. a good discussion also ensures that the original research question, as outlined in the introduction, was answered effectively. in 2009 the south african journal of sports medicine will be adopting revised guidelines for authors. these will be published on the website (www.sajsm.org.za./index.php/sajsm). in accordance with the new guidelines, the editorial staff is going to be strict about the number of references with each paper. the reason for restricting the number of references is not to curtail information linked to the study, but rather it is a pragmatic decision which relates to the number of pages per edition and cost of publishing the journal. readers of the journal will rightly be unimpressed if a large proportion of the journal is dedicated to references, at the expense of new content. all the people who reviewed papers in 2008 are thanked most sincerely – without exception the standard of the reviews was very high. anyone who has reviewed for a journal knows that it is a thankless job – there is no payment or recognition, and it is just one of those commitments that one is obliged to make as a scientist. having been on the receiving end many times myself, it is never pleasant to have a paper rejected. however, it makes it a bit easier to accept the decision if the standard of the review is high. so to all the reviewers, many thanks, your contribution to the south african journal of sports medicine is greatly appreciated! mike lambert editor-in-chief 1. ncayiyana dj. racial profiling in medical research: what are we measuring? s afr med j 2007; 97: 1225-1226. accepted or rejected? a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial sajsm vol 20 no. 4 2008 94 original research 1 sajsm vol. 30 no. 1 2018 anterior cruciate ligament injuries of the knee: patterns of association between the mechanism of injury and pathology visualised on magnetic resonance imaging g l strauss, mbchb,m.sports.med1,2, d c janse van rensburg, mbchb, msc, mmed, md2, c c grant, phd2, a jansen van rensburg, msc2, m d velleman, m.med rad d, fc rad1,3, l fletcher, phd4 1 department of diagnostic radiology, university of pretoria, pretoria, south africa. 2 section sports medicine, university of pretoria, pretoria, south africa. 3 life groenkloof hospital medical centre, capital radiology and pretoria mr trust, pretoria, south africa. 4 department of statistics, faculty of natural and agricultural sciences, university of pretoria, pretoria, south africa. corresponding author: g l strauss (orgstrauss@yahoo.com) the increase in acl injuries in recent years in athletes as well as in the general population is concerning.[1] although acl injuries are common, the mechanism of injury is still not clearly defined. the acl is one of the most frequently injured of the four knee ligaments. the function of the acl is critical as a stabiliser of the knee joint during movement as well as preventing dislocation. the acl also contributes to the stability of other movements of the knee joint, including angulation and rotation.[2] these functions are performed by the attachment of the acl to the femur at the proximal end and to the tibia at the distal end. the other major ligaments of the knee contributing to movement and stability include the posterior cruciate ligament (pcl) and the medial and lateral collateral ligaments (mcl and lcl) respectively.[2] contact and non-contact sports as well as certain leisure activities, where the knee joint needs to move in different planes, such as with a change of direction, can put stress on the knee joint. holtzhausen et al. found that ligament sprains were the most common injuries during the 2005 super 12 rugby competition with the knee as the second highest injury site.[3] similarly, during the 2007 rugby world cup ligament injuries were one of the most common injuries with knee ligament injuries as the main type of injuries, while during the 2010 women’s rugby world cup, 15% of injuries were of the knee ligament.[4,5] a review of studies investigating the biomechanics of acl injuries revealed that the mechanism of injury is multi-factorial. [numerous studies associated with acl injuries and their mechanisms were identified. evidence regarding plane of injury, supporting sagittal, frontal and/or transverse plane of mechanism was strong throughout. these studies indicated that it is highly probable that acl injuries are more likely to occur during multi-planar rather than single-planar mechanism of injury.[6] this emphasises the need for grading of acl injury. according to published literature, it is clear that sports and activities requiring multi-plane movement of the knee have a higher risk of injury.[6] variations in anatomy and gender may background: anterior cruciate ligament (acl) injuries are common among athletes and the general public. these injuries may lead to significant absence from all activities with associated financial and social burdens for the patient. no definitive association has been described between the mechanism of injury and the pathology to enable the implementation of preventative measures to limit these injuries. aim: to determine whether there is an association between the mechanism of injury and the pathology seen on a magnetic resonance imaging (mri) scan in acl injuries. methods: this was a cross-sectional analytical study. eighty-seven male patients with an acl injury and who had an mri scan of the knee within the last two years participated in this study. participants were contacted to give their informed consent to participate in this study. the mechanism of injury and the pathology seen on the mri scan was noted and categorised into different groups of injuries and associated pathologies. statistical analyses included summaries of the data and a test for the association between the mechanism of injury and the pathology. since there were multiple pathology responses to each mechanism, a modified version of the chi-square test for independence was used. a five percent level of significance was specified. results: mri scans of acl injuries indicated that the mechanism of a solid foot plant with rotation of the knee has a greater tendency to be associated with medial meniscal injuries (77%). there was also a 54% possibility for it to be associated with lateral meniscal injuries. a solid foot plant with a valgus stress on the knee showed a higher incidence of associated medial collateral ligament (mcl) injuries (41%) and femoral bone bruising (62%). these two mechanisms of injury are the most common in acl injuries and contribute to the clinical significance found in this study. the p-value was, however, not statistically significant (p=0.44, chi-square value=20.27, df=45) for any association between the pathology and the mechanism of injury. conclusion: some injury mechanisms causing an acl injury were more common than others and had more associated pathologies. the most common mechanism of injury noted in this study was a solid foot plant with either rotation of the knee or valgus stress on the knee. strengthening the tissue structures involved in those movement patterns causing these mechanisms can possibly limit future acl injuries in athletes and the general public. keywords: knee injury, mechanism, association, pathology, mri scan, prevention s afr j sports med 2018; 30:1-6. doi: 10.17159/2078-516x/2018/v30i1a5265 http://dx.doi.org/10.17159/2078-516x/2018/v30i1a5265 original research sajsm vol. 30 no. 1 2018 2 also contribute to a higher incidence for this type of injury. an understanding of the different factors contributing to these injuries is particularly important in preventing acl injuries.[6] in recent years the method of using magnetic resonance imaging (mri) to grade an acl injury has become popular.[7] this involves the use of a four point scoring system from the mri scans, namely, intact, low-grade partial tear, high-grade partial tear and complete tear. this injury severity classification resulted from comparisons to arthroscopic findings.[7] the aim of this study was to investigate the association between the pathology of acl injuries and the mechanism of injury as seen on an mri scan of the knee. methods this was a cross-sectional analytical study. eighty-seven male patients with an acl injury and who had an mri scan of the knee within a two-year period were voluntarily included in this study. participants were contacted to give informed consent for their information be used in this study. inclusion criteria specified that the patient should have a history of a complete acl tear of the knee, have a clear history of the mechanism of the injury, and that knee surgery was not compulsory. participants were not excluded based on age and fitness levels. female patients and patients who could not recall the exact mechanism of their acl injury were excluded from this study. for this study, an acl injury refers to a complete tear of the acl. the mechanism of injury is the exact manner how the acl was injured using six groups as listed in table 1. contact and non-contact injuries were included. an mri of the knee refers to imaging done on a magnetic resonance imaging scanner. these images were obtained with a 1.5 or 3 tesla mri scanner using a three mm slice thickness and a 0.3 mm gap. the sequences acquired were t2w fat saturated in the axial, coronal and sagittal planes, as well as proton density, sagittal and coronal sequences. the pathology was defined as abnormal findings in and around the knee joint related to the acl injury, using the ten most common groups as listed in table 2. mri scan reports and contact numbers of male patients scanned during a two-year period were obtained. permission to use this data was obtained from the radiology practise. the specific mechanism of injury and management plan of each patient was obtained telephonically. the exact questions asked telephonically were: question 1: how did you injure your knee? question 2: please explain the exact mechanism. the mechanism of injury was not further divided into more specific sub-categories due to the possible difficulty individuals may have in recalling this level of detail of their injury. patient names and data used in this study were anonymous. each patient received an information letter explaining the study and written consent was obtained from each patient to use their injury and mri scan findings. the information letter and informed consent form were emailed to the patient. the specific questions asked telephonically were stipulated in the informed consent form. after signing the information letter and informed consent form in the presence of a witness, the patient scanned the document and emailed it back to the principal investigator. the protocol was submitted to the ethics committee of the university of pretoria and ethical approval was obtained (ref. 375/2017). statistical analysis the data were analysed using the ibm spss statistics program (version 24). results were entered into an excel spread sheet (microsoft 2010), summarised in tables, and graphically displayed with bar charts (i.e. to portray the profiles of the injuries per mechanism). since the data can be regarded as multiple response sets (there are multiple pathology responses per mechanism) the standard chi-square test for independence was unsuitable. a modified version of the chi-square test, namely, a single-by-multiple marginal independence test, using the rao-scott corrected chi-square approximation to the sampling distribution, was used instead.[8,9] a five percent level of significance was specified to test the null hypothesis of independence. results the age of the patients participating in this study ranged from 14 to 67 years, with 31 years being the average age (±13) years. the self-reported level of physical activity, fitness and general conditioning differed between individuals. the mechanism of injury according to the broad groups listed and compared to the observed pathology on the mri scan and patient experience is indicated in table 3 and figure 1 respectively. although the p-value was not statistically significant at 0.44 (chi-square value=20.27, df=45), the results show clinical importance in a number of ways. table 1. mechanism of injury mechanism 1 solid foot plant with rotation of the knee. mechanism 2 solid foot plant with valgus stress on the knee. mechanism 3 twist of the knee without foot plant. mechanism 4 hyperextension injury of the knee. mechanism 5 injury during changing of direction while running or walking mechanism 6 none of the above mentioned specific mechanisms of injury were present. table 2. pathology on the mri scan pathology 1 other associated soft tissue injuries around the knee joint not mentioned below. pathology 2 associated fractures of the bones around the knee joint. pathology 3 complete anterior cruciate ligament tear. pathology 4 medial meniscus injury (including any pathology). pathology 5 lateral meniscus injury (including any pathology). pathology 6 femoral bone bruise. pathology 7 tibial bone bruise. pathology 8 haemarthrosis or knee effusion present. pathology 9 associated mcl injury (including any pathology). pathology 10 associated lcl injury (including any pathology). original research 3 sajsm vol. 30 no. 1 2018 mechanism 1 – a solid foot plant with rotation of the knee had a high percentage of associated medial meniscal (77%) and lateral meniscal injuries (54%). tibial bone bruises (57%) were more common than femoral bone bruises (40%). only 26% had an associated mcl injury and 37% had a haemarthrosis. few had an associated injury of the lcl (11%). associated fractures accounted for a very small percentage of pathology found. the mechanism of solid foot plant (m1 and m2) accounted for 79% of acl injuries. mechanism 2 – a solid foot plant with valgus stress on the knee had the highest percentage of acl injuries associated with bone bruising (femoral 62%, tibial 59%), followed by meniscal injuries (medial 53% and lateral 50%). associated mcl injuries (41%) were more common compared to lcl injuries (3%), and 32% of acl injuries had a haemarthrosis for this mechanism. mechanism 3 no acl injuries were observed where the mechanism of injury related to a twist of the knee without foot plant (m3). mechanism 4 hyperextension injury of the knee indicated a high percentage of associated bone bruising (tibial 71%, femoral 64%) as an associated pathology. more associated medial meniscal injuries (64%) were seen and fewer lateral meniscal injuries (43%). mcl injuries (57%) were far more common than lcl injuries (0%). haemarthrosis accounted for 43% of injuries. table 3. the observed counts of the mechanism of injury (m) versus the pathology (p) identified on the mri scan p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 total no. of patients mechanism other fracture acl medial meniscus lateral meniscus femoral bone bruise tibial bone bruise haemarthroses effusion mcl lcl m1 21 2 35 27 19 14 20 13 9 4 164 35 (40%) m2 17 2 34 18 17 21 20 11 14 1 155 34 (39%) m4 6 2 14 9 6 9 10 6 8 0 70 14 (16%) m5 1 0 2 2 1 1 0 0 1 0 8 2 (2%) m6 2 0 2 2 1 0 0 0 0 0 7 2 (2%) total 47 6 87 58 44 45 50 30 32 5 404 87 data presented as counts or percentage (%). for each mechanism (m1 to m6), there are ten different possible pathology types (p1 to p10). there may be multiple pathology responses per mechanism. acl, anterior cruciate ligament; lcl, lateral collateral ligament; mcl, medial collateral ligament. fig. 1. clustered bar chart of proportion (%) of each mechanism by pathology. there may be multiple pathology responses per mechanism. acl, anterior cruciate ligament; lcl, lateral collateral ligament; mcl, medial collateral ligament. original research sajsm vol. 30 no. 1 2018 4 mechanisms 5 and 6 the less common mechanisms (m5 and m6) of injury had a high percentage of medial meniscal injuries, less lateral meniscal injuries and almost no collateral ligament and bone bruising injuries. related fractures were uncommon for all mechanisms. discussion mechanism 1, a solid foot plant with rotation of the knee, was the most frequent mechanism. this type of injury also has a greater tendency to be associated with medial meniscal injuries (77%) and a 54% possibility of being associated with lateral meniscal injuries. a solid foot plant with a valgus stress on the knee (mechanism 2) was the second most common mechanism. when compared to mechanism 1, a higher incidence of associated mcl injuries (41%) and femoral bone bruising (61%) were reported for mechanism 2. these findings are in line with findings from previous studies.[10] in this study the most common associated pathologies when the acl was injured included medial meniscal, tibial bone bruise, femoral bone bruise and lateral meniscal injuries. previous studies reported mcl injury and haemarthrosis as the most commonly associated pathology.[10] this is not replicated in the current study. mechanisms of acl injury the most common mechanism of injury reported in this study, namely mechanism m1 and m2 (solid foot plant with rotation of the knee, and solid foot plant with valgus stress on the knee, respectively) corresponded well with the findings of boden et al.[11] these researchers reported that significant advances have recently been made in understanding the mechanisms involved in non-contact acl injuries. they found that most acl injuries involve minimal to no contact.[11] recent video analyses demonstrate significant differences in average leg and trunk position during injury compared to those in control subjects. axial compressive forces are a critical component in non-contact acl injuries. above mentioned findings as well as those found in cadaveric and mri studies found this statement to be true.[11] a study by sturnick et al. found that a decreased volume of the medial tibial spine is associated with an increased risk of acl injuries in males only. a similar finding was not observed in females. their analyses of males also revealed that an increased medial tibial spine volume was associated with a decreased risk of acl injury. they found evidence to support the fact that smaller medial spines may provide less resistance to internal rotation and medial translation of the tibia relative to the femur. this could increase the chance of acl sprains and the risk of acl injury.[12] the most common mechanism of injury in this study did involve a solid foot plant with rotation of the knee and valgus stress on the knee, which corresponds well with the findings in the study by sturnick et al., as a more prominent medial tibial spine could prevent the knee from a twist or valgus type injury mechanism.[12] the mechanism of acl injury identified in this study as occurring most frequently is also identified in another published review that found that most acl injuries do not occur solely via sagittal, frontal or transverse plane mechanisms.[13] collectively, the results showed that acl injuries are more likely to occur during multi-planar rather than single-planar mechanisms of injury.[13] a study by yu and garrett on acl injuries in soccer players found that sagittal plane biomechanical factors such as small knee flexion angle, considerable posterior ground reaction force and quadriceps muscle force may be associated with significant quadriceps muscle force, in turn causing substantial anterior draw force at the knee.[14] the study further concluded that a small knee flexion angle is associated with a large patella tendon-tibia shaft angle and acl elevation angle. this would result in excessive acl loading. knee valgus-varus moment and internal-external rotation moment alone are unlikely to result in isolated acl injuries without injuring other knee structures. [14] these results confirmed that the mechanism of acl injury occurs in many planes. a study by fuller et al. (2010) investigated the risk of injury associated with rugby union games played on artificial turf. the results showed that the incidence of acl injuries were nearly four times higher when the game was played on artificial surfaces compared to grass surfaces. this could be due to the different mechanism of foot plant and knee rotation causing the injury.[15] these findings may also link the solid foot plant mechanism (m1 & m2) found in this present study as an important mechanism of injury; however, it needs to be further investigated and confirmed. associated pathology viskontas et al. investigated the correlation between bone bruise patterns and the mechanism of injury in acl ruptures. their results indicated that non-contact knee injury mechanisms appear to cause more severe bone bruising in both the medial and lateral compartments.[10] although bone bruising was not the most common associated pathology found in this present study, it did account for more than 50% of associated injuries found in the most common mechanisms of injury, namely, m1, m2 and m4. prevention of acl injuries to understand the role and place of this present study and to interpret the results and make appropriate recommendations, the philosophy, theories and components of the prevention of acl injuries and sport injuries in general must be considered. a systematic approach to the prevention of sports injuries as shown in figure 2 below has been described by van mechelen et al..[16] fig. 2. model of systematic approach to injury prevention original research 5 sajsm vol. 30 no. 1 2018 this present study could play an important role in establishing the causes of injury and the introduction of preventative measures. research into the prevention of acl injuries is very important and necessary. a study done in the united states found that paediatric patients who returned to sport too early after acl reconstruction surgery had a higher risk for reinjuring the ligament. proper rehabilitation protocols and return-to-sport recommendations should be in place and implemented to prevent this from happening.[17] a study by wellsandt et al. found that limb symmetry indexes can overestimate knee function after acl injury and may be related to secondary acl injury risk. these findings raise concerns as to whether the variety of criteria regarding return-to-sport utilised in current clinical practise is stringent enough to achieve a safe and successful return to sport.[18] this emphasises the need for standardised return-to-play protocols and that more than one factor should be considered when a return-to-play decision is made after acl reconstructive surgery. it is, however, important to understand that the values obtained from testing is not the only indicative factor to consider for functional knee movement, and that other biomechanical factors are also very important in preventing acl injuries. multifaceted programmes supported by videos and/or technical feedback, including eccentric hamstring exercises, would positively modify the biomechanical and/or neuromuscular anterior and/or hamstring injury risk factors.[19] strong evidence the most common mechanisms of injury identified were a solid foot plant with rotation of the knee (m1) and valgus stress on the knee (m2), indicating a solid foot plant as the common denominator. these mechanisms led to more associated pathologies after injury in this study. it is clear from the findings in this study that movement patterns in athletes should change to prevent the foot from being planted flat and solidly during movement so that it prevents the foot from changing its position during the second movement, and knee joint stress with the second movement. this is a convincing reason to improve the strength of the lower leg muscles to help with flexion/extension of the ankle and inversion/eversion of the foot, as well as changing the biomechanics and movement patterns of the lower limbs, in order to assist the altered foot movements needed to prevent injury. the mechanisms of injury where a solid foot plant was not present occurred far less commonly with less associated pathology. this supports the abovementioned recommendation of improving foot plant and position of the foot during activity to prevent acl injury. weaker evidence the fact that no statistically significant evidence of an association between the mechanism of injury and the pathology seen on the mri scans could be found was most likely due to the small sample size and the commensurate lower power of the test in this study?. using a larger sample size and dividing the pathology in even larger similar groups could be considered in future studies. trends this study showed that acl injuries are common in all ages of the population and can occur at different levels of activity. some mechanisms are also indicated as more common than others. attending to and correcting the movement patterns behind these injury mechanisms can assist in preventing acl injuries in the future and limit the burden of these injuries on the professional sportsman and general public. limitations limitations of this study included: 1) recall bias, as some patients could not give an exact description of the mechanism of their injury, 2) the group of patients used was randomly selected and not a homogenous group, 3) there were fairly large age differences in the patients, 4) the level of physical activity and conditioning of patients differed significantly, with some being professional sports people. conclusion although no statistical significant association between the mechanism of injury and pathology as observed on a mri scan could be proven in this study, some clinical relevant observations are reported. this research enables a better understanding of the specific mechanism of acl injuries of the knee with the most common mechanisms of injury, a solid foot plant with either rotation of the knee or valgus stress on the knee. the findings also assist in improving the current knowledge of pathology patterns related to the mechanism of acl injuries. these specific patterns of acl injuries remain essential to the radiologists and sports physicians to document the multi plane movement of the knee which have a higher risk of injury. this awareness is furthermore crucial to the physiotherapist, biokineticist, personal trainer and coach improving movement patterns, implement preventative measures, and apply a pro-active programme specifically for athletes, in order to limit the number of acl injuries. references 1. dodson cc, secrist es, bhat sb, et al. anterior cruciate ligament injuries in national football league athletes from 2010 to 2013: a descriptive epidemiology study. orthop j sports med 2016; 4(3): 2325967116631949. [doi:10.1177/2325967116631949] 2. brukner p, khan k. clinical sports medicine. 3rd ed. mcgrawhill, 2006:472-494. 3. holtzhausen lj, schwellnus mp, jakoet i, et al. the incidence and nature of injuries in south african rugby players in the rugby super 12 competition. s afr med j 2006;96(12): 1260-1265. 4. fuller cw, laborde f, leather rj, et al. international rugby board rugby world cup 2007 injury surveillance study. br j sports med 2008;42(6): 452-459. [doi:10.1136/bjsm.2008.047035] 5. taylor ae, fuller cw, molloy mg. injury surveillance study during the 2010 irb women’s rugby world cup. br j sports med 2011;45(15):1243-1245. [doi: 10.1136/bjsports-2011-090024] 6. quatman ce, quatman-yates cc, hewett te. a ‘plane’ explanation of anterior cruciate ligament injury mechanisms: a systemic review. sports med 2010;40(9):729-746. [doi:10.2165/11534950-000000000-00000] original research sajsm vol. 30 no. 1 2018 6 7. hong sh, choi jy, lee gk, et al. grading of anterior cruciate ligament injury. diagnostic efficacy of oblique coronal magnetic resonance imaging of the knee. j comput assist tomogr 2003;27(5):814-819. [pmid: 14501376] 8. thomas dr, decady yj. testing for association using multiple response survey data: approximate procedures based on the rao-scott approach. int j testing 2004; 4(1): 43-59. [doi: 10.1207/s15327574ijt0401_3] 9. agresti a, liu im. modelling a categorical variable allowing arbitrarily many category choices. biometrics. 1999;55(3):936943. [pmid: 11315032] 10. viskontas dg, giuffre bm, duggal n, et al. bone bruises associated with acl rupture: correlation with injury mechanism. am j sports med 2008;36(5):927-933. [doi: 10.1177/0363546508314791] 11. boden bp, sheehan ft, torg js, et al. noncontact anterior cruciate ligament injuries: mechanisms and risk factors. j am acad orthop surg 2010; 18(9):520-527. [doi:10.5435/00124635201009000-00003] 12. sturnick dr, argentieri ec, vacek pm, et al. a decreased volume of the medial tibial spine is associated with an increased risk of suffering an anterior cruciate ligament injury for males but not females. j orthop res 2014;32(11):1451-1457. [doi: 10.1002/jor.22670] 13. barraza lc, krishna rg, low jh, et al. the biomechanics of acl injury: progresses toward prophylactic strategies. crit rev biochem eng 2013;41(4-5):309-321. [doi:10.1615/critrevbiomedeng.2014010460] 14. yu b, garrett we. mechanism of non-contact acl injuries. br j sports med 2007;41 suppl 1:i47-51. [doi: 10.1136/bjsm.2007.037192] 15. fuller cw, clarke l, molloy mg. risk of injury associated with rugby union played on artificial turf. j sports sci 2010;28(5):563570. [doi: 10.1080/02640411003629681] 16. verhagen ea, van mechelen w, . sport for all, injury prevention for all. br j sports med 2010;44(3):158. [doi: 10.1136/bjsm.2009.066316] 17. dekker tj, godin ja, dale km, et al. return to sport after pediatric anterior cruciate ligament reconstruction and its effect on subsequent anterior cruciate ligament injury. j bone joint surg am 2017;99(11):897-904. [doi: 10.2106/jbjs.16.00758] 18. wellsandt e, failla mj, snyder-mackler l. limb symmetry indexes can overestimate knee function after anterior cruciate ligament injury. j orthop sports phys ther 2017;47(5):334-338. [doi: 10.2519/jospt.2017.7285] 19. monajati a, larumbe-zabala e, goss-sampson m, et al. the effectiveness of injury prevention programs to modify risk factors for non-contact anterior cruciate ligament and hamstring injuries in uninjured team sports athletes: a systemic review. plos one 2016;11(5):e0155272. [doi: 10.1371/journal.pone.0155272] it can be said without doubt that every scientist who has done research and tried to publish a paper in a journal has at some stage been at the receiving end of the peer-review process. there are different forms of peer review associated with publishing research but the most common version is where the editor of the journal chooses reviewers (at least two) who are asked to provide a critique of a paper which has been submitted to the journal. the reviewers are asked to make a recommendation on whether or not the paper should be published. the identity of the authors is not revealed to the reviewers and usually the reviewers are not known to the authors. reviewers are not paid for their efforts despite the process taking several hours. it is an unwritten code that being asked to review a paper is pay-back for the occasions on which one’s own research is reviewed by other unknown scientists. this is the style of review used by the south african journal of sports medicine. not everyone supports peer review as it is currently practised. most of the complaints concern the slow process and the fact that sometimes reviewers might reject a paper because it does not fit into their own research paradigm. furthermore, the process often fails to detect errors in analysis, ethical problems or scientific fraud. 1,2 the system has also been accused of blocking innovation and the promotion of new ideas. 1 the chance of two reviewers of a paper giving identical reports and identifying the same problems with the paper are remote. to counter this problem several reviewers need to be used, but this imposes large time and financial hurdles which most journals find unacceptable. 1 a recent report concluded that improving peer review ‘…depends on making its human aspects more humane. journals need to ask the right reviewers to review the right articles, help them to do it quickly and thoroughly, make them feel happy to sign their reports, thank them, tell them how they did, and encourage wide recognition of what’s too often a thankless task’. 1 high-quality journals address these points and facilitate the reviewing process by having a large database of reviewers with records of which papers they have reviewed, when they last reviewed a paper, an online tracking system, automated reminders and strict deadlines. whilst we do not have a sophisticated online tracking system at the sajsm we do try to enforce strict deadlines for reviewers. however, this process is undergoing change and we hope that by this time next year we will have an online submission with better tracking systems for reviewers. a problem with the smaller specialist journals such as the sajsm is the relatively small pool of potential reviewers. we aim to increase this pool by marketing the journal beyond the confines of the members of the south african sports medicine association and if there is sufficient interest we will have workshops on peer review for interested members who may lack experience in reviewing papers. however, given the acknowledged limitations of peer review it remains the only practical system of quality control presently available. until a better system evolves or is invented we have to accept and embrace the process and make sure that all the factors which facilitate a smooth reviewing process are controlled. mike lambert editor-in-chief 1. groves t. quality and value: how can we get the best out of peer review? nature 2006; 441: xi xi. 2. smith r. peer review: reform or revolution? bmj 1997; 315:759-760. peer review – a part of the process? a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm sajsm vol 18 no. 4 2006 105 editorial pg105.indd 105 11/22/06 12:17:45 pm it is difficult to ignore the media attention and public health messages about the current obesity epidemic and the emphasis to reduce body weight. despite some cynicism about the true status and implications of the obesity epidemic,1 there is no doubt that preventing weight gain can contribute to improving the health of the nation.2 the efficacy of exercise as a means of weight reduction is regularly scrutinised and doubted.3 body weight loss is commonly regarded as the marker of efficacy by researchers, and more typically the perceived measure of success by lay people. any lack of weight loss associated with exercise is often attributed to poor compliance and/or compensation for the acute exercise-induced increase in energy expenditure.4 that is, the net change in exercise-induced energy expenditure is modest and insignificant due to compensatory adjustments in energy intake and a failure to comply fully with the exercise prescription. clearly, if people do not comply with the exercise prescribed (by themselves or others), the expected weight loss will not occur. the success of exercise in promoting weight loss will vary between individuals;5 however, those who lose less weight should not be labelled as failures or be perceived negatively. evidence suggests that individuals have unrealistic weight loss expectations,6 which is indicative of an inappropriate focus on body weight. blair and lamonte suggested that ‘a focus on weight loss is often counterproductive and unsuccessful, and sometimes may even be unnecessary.’7 furthermore, body weight per se might not be the most important risk factor for obesity comorbidities.8-10 it is possible that media attention and the persistent barrage of messages to reduce obesity are to blame for the obsession with the capacity of exercise to produce marked and rapid weight loss. exercise gives rise to a wide range of health benefits, not just weight loss.11 disappointment and low self-esteem associated with poor weight loss could lead to low exercise adherence and a general perception that exercise is futile and not beneficial. this viewpoint is potentially damaging – a more transparent and positive attitude to the health benefits of exercise is required. individuals who drop out of exercise interventions – possibly due to disappointing weight loss – have a history of previous weight loss attempts, and exercise adherence is associated with intrinsic motivation.12,13 unfortunately, focusing on beneficial effects of exercise: shifting the focus from body weight to other markers of health* abstract background: exercise is widely promoted as a method of weight management, while the other health benefits are often ignored. the purpose of this study was to examine whether exercise-induced improvements in health are influenced by changes in body weight. methods: fifty-eight sedentary overweight/obese men and women (bmi 31.8 (sd 4.5) kg/m2) participated in a 12-week supervised aerobic exercise intervention (70% heart rate max, five times a week, 500 kcal per session). body composition, anthropometric parameters, aerobic capacity, blood pressure and acute psychological response to exercise were measured at weeks 0 and 12. results: the mean reduction in body weight was -3.3 (3.63) kg (p<0.01). however, 26 of the 58 participants failed to attain the predicted weight loss estimated from individuals’ exercise-induced energy expenditure. their mean weight loss was only -0.9 (1.8) kg (p<0.01). despite attaining a lower-than-predicted weight reduction, these individuals experienced significant increases in aerobic capacity (6.3 (6.0) ml/kg/min; p<0.01), and a decreased systolic (-6.00 (11.5) mmhg; p<0.05) and diastolic blood pressure (-3.9 (5.8) mmhg; p<0.01), waist circumference (-3.7 (2.7) cm; p<0.01) and resting heart rate (-4.8 (8.9) bpm, p<0.001). in addition, these individuals experienced an acute exercise-induced increase in positive mood. conclusions: these data demonstrate that significant and meaningful health benefits can be achieved even in the presence correspondence to: dr n king, institute of health and biomedical innovation, school of human movement studies, queensland university of technology, brisbane, 4059, qld, australia; n.king@qut.edu.au parts of these data were presented at bases in uk, 2006, and at the 9th ico in australia, 2006. accepted 24 august 2009 published online first 29 september 2009 *this article has been reproduced with permission from the bmj group. it was originally published in the british journal of sports medicine 2009;43:924-927. n a king,1 m hopkins,2 p caudwell,3 r j stubbs,4 j e blundell3 1 institute of health and biomedical innovation, school of human movement studies, queensland university of technology, brisbane, australia 2 department of health and exercise science, trinity and all saints college, leeds, uk 3 biopsychology group, institute of psychological sciences, university of leeds, leeds, uk 4 slimming world, clover nook road, somercotes, alfreton, uk editor`s choice 46 sajsm vol 22 no. 2 2010 of lower-than-expected exercise-induced weight loss. a less successful reduction in body weight does not undermine the beneficial effects of aerobic exercise. from a public health perspective, exercise should be encouraged and the emphasis on weight loss reduced. sajsm vol 22 no. 2 2010 47 exercise-induced changes in body weight undermines the arguably more important health benefits associated with exercise. although there is some debate about the direct association between weight loss per se and health benefits, there is evidence to suggest that reductions of 5 10% in body weight improve some health risk markers.14 for several years steve blair has promoted the idea that fitness is more important than fatness, since there are data to demonstrate that a fat but fit person has fewer health risks than a lean but unfit individual.15 there is a real need to promote physical activity and to prevent it being undervalued by the community and by public health professionals.16 in fact, when sedentary people undertake exercise, the activity provides a massive stimulus with widespread physiological implications. the effect cannot be readily anticipated, but studies have noted considerable diversity in the responses.17,18 in addition, the energy expended in exercise is believed, by some,19 to stimulate compensation so that energy balance is preserved. we have examined these issues under controlled scientific conditions. materials and methods fifty-eight sedentary overweight/obese men (bmi 30.5 (sd 3.3) kg/ m2) and women (bmi 32.6 (4.8) kg/m2) completed a 12-week supervised aerobic exercise programme (70% heart rate max) five times a week in the human appetite research unit at the university of leeds. each exercise session was designed to expend approximately 500 kcal. body composition (air plethysmography – bodpod, concord), anthropometry, aerobic capacity (submaximal vo2max test), blood pressure, resting heart rate and the acute affective response (positive and negative affect scale (panas)20) to exercise were measured at weeks 0 and 12. subjects were instructed not to restrict their energy intake during the study. results when all 58 subjects’ data were pooled, the mean reduction in body weight was -3.3 (3.6) kg (p<0.01). however, there was large interindividual variability (fig. 1). based on empirical evidence,21 the mean weight loss matched the predicted weight loss. further examination of the weight-change data revealed that subjects could be categorised into two groups (responders and non-responders) based solely on their actual initial weight relative to the calculated weight change. calculations were based on the assumed energy costs of 9 540 kcal/ kg and 1 100 kcal/kg of fat mass and fat-free mass respectively.21 the non-responders (n=26) lost less weight than predicted based on their individual total exercise-induced energy expenditure. although statistically significantly lower than baseline (week 0), their mean weight loss was only -0.9 (1.8) kg (p<0.01), compared with the remaining participants (responders) who experienced an average weight loss of -5.2 (3.64) kg (p<0.01). indeed, some of the classified non-responders actually gained weight. therefore, based on body weight alone, exercise could be regarded as ineffective and futile for the non-responders (and even counterproductive for the weight gainers). however, the effectiveness of exercise should not be exclusively judged on changes in body weight because it undermines the other health benefits that are commonly associated with exercise. despite the lower-than-expected weight loss, the non-responders did achieve improvements in health markers. they experienced a significant increase in aerobic capacity (6.3 (6.0) ml/kg/min; p<0.01), reduction in waist circumference (-3.08 (2.66) cm; p<0.01), and decreases in systolic (-6.0 (11.5) mmhg; p<0.05), diastolic blood pressure (-3.9 (5.8) mmhg; p<0.01) and resting heart rate (-4.8 (8.9) bpm; p<0.001) (fig. 2). the reduction in both systolic and diastolic blood pressure was more marked when examining the changes in those individuals who were classed as hypertensive (140/90 mmhg) at baseline. they experienced a significant reduction in systolic (-15 (10.4) mmhg; p<0.0001) and diastolic (-10 (4.6), p<0.0001) blood pressure. in addition to the reduction in health risk markers, the nonresponders experienced an acute improvement in psychological state reflected in the exercise-induced increase in positive mood, which was maintained during the 12 weeks. interestingly, although the difference in weight loss between the groups was statistically significant, there were no statistically significant differences in the health benefits. furthermore, when all subjects’ data were pooled, there was no association between weight loss and improvements in health markers. therefore, the exercise itself, independent of weight loss, made a significant contribution to the health benefits. there were no significant differences between men and women, and the proportion of men in each group was similar (responders=men:women, 9:23, 28% and non-responders=men:women, 10:16, 38%). moreover, these results show that if people fail to lose weight following a recommendation to perform physical activity, it is not necessarily a result of poor compliance. in some individuals who are resistant to weight loss, it will be due to strong physiological compensatory processes. fig. 1. variability in individual changes in body weight (kg) after 12 weeks of monitored exercise. fig. 2. mean reduction in resting heart rate during the 12-week exercise intervention in r and nr. there was a significant main effect of week but no statistically significant main effect of group or group x time interaction. discussion these data demonstrate that significant and meaningful health benefits can be achieved even in the presence of lower-than-expected exercise-induced weight loss. a novel feature of this study is that the exercise intervention was supervised, and each session was monitored and measured directly. therefore, unlike most of the other exercise intervention trials, we can guarantee that the lowerthan-expected weight loss was not due to poor compliance. indeed, the degree of adherence and total exercise energy expenditures did not differ between the two groups. importantly, based on each individual’s predicted weight loss, those who lost less weight than predicted still experienced improvements in other markers of health. it is important to note that these health markers are not overtly accessible to most individuals, whereas other markers such as body weight, perceptions of fitting of clothes and perceived body image are more accessible and transparent. therefore, most individuals are ‘blind’ to the exerciseinduced health improvements. indeed, these data demonstrate that subjects who lost less than the predicted weight still experienced a mean reduction of approximately 3.7 cm in waist circumference. waist circumference is promoted as being more important than bmi at predicting risk of obesity-related disease,22,23 and a better marker of success than bmi in response to exercise.24 the reductions in diastolic and systolic blood pressure in the non-responders were similar to other studies.25 there is a need to increase knowledge and understanding of the health benefits of exercise, and reduce the emphasis on weight loss.11 this agrees with the evidence that cardiorespiratory fitness is a more powerful predictor of risk than body weight.16 in addition, evidence from the finnish diabetes preventions study showed that individuals who did not lose weight but who did increase their physical activity maintained a reduction in the risk of diabetes.26 exercise should be promoted as an optimistic method of improving weight management and overall health by highlighting the importance of using other markers of success. weight loss is not the only benefit of exercise; nor is it the most useful and appropriate marker of health.27 a recent intervention in postmenopausal obese women using low-intensity, low-volume exercise showed improvements in cardiorespiratory fitness with no effect on body weight.28 furthermore, partly due to the culture of focusing on obesity and weight loss, individuals will actively seek opportunities which are specifically targeted to promote weight loss – and exercise is one of those. from a public health perspective, exercise should therefore be encouraged; and even though body weight may not change markedly, or match expectations, lean tissue will be increased (or preserved), and body shape will change (waist circumference). there will also be a lowering of risk factors for comorbidity problems and diabetes. in the present study, the reduction in waist circumference – even in the non-responders – is important, since this variable is a proxy measure of visceral fat which is highly associated with cardiometabolic risk factors.11 it may therefore be important to encourage the replacement of bmi and body weight with waist circumference as a measure of the effectiveness of exercise. within this framework, there is a key role for physicians and health professionals. these professionals (including dietitians) not only can promote physical activity as a contribution to health but also can be instrumental in improving weight management in nonresponders (table i). we have demonstrated that non-responders fail to lose the expected weight because of an increase in appetite reflected in an increased selection of high-fat foods and a decrease in fruit and vegetable consumption29 and because of an increased orexigenic (hunger) response.30 therefore, using dietary behaviour 48 sajsm vol 22 no. 2 2010 table i. mean absolute and percentage changes in anthropometry, body composition and health markers after 12 weeks of monitored exercise in responders (n=32) and non-responders (n=26) variable group absolute change change (%) body mass (kg) responders -5.2 -5.7 non-responders -0.9 -1.0 bmi (kg/m2) responders -1.8 -5.7 non-responders -0.3 -1.0 fat mass (kg) responders -4.9 -15.3 non-responders -1.2 -4.7 body fat (%) responders -3.5 -10.5 non-responders -1.1 -3.7 lean mass (kg) responders -0.3 -0.6 non-responders +0.3 +0.4 waist circumference (cm) responders -6.0 -5.8 non-responders -3.7 -3.7 vo2max (ml/kg/min) responders +9.1 +32.5 non-responders +6.3 +23.0 diastolic blood pressure (mmhg) responders -3.4 -3.7 non-responders -3.9 -4.6 systolic blood pressure (mmhg) responders -2.9 -1.9 non-responders -6.0 -4.3 for both groups, exercise-induced statistically significant changes in all variables; however, none of the differences between the groups were statistically significant. sajsm vol 22 no. 2 2010 49 strategies, dietitians and health professionals could help to counter appetite stimulation in the non-responders and therefore help weight management while preserving all of the health benefits of exercise. in conclusion, these data provide support for the belief that poor weight loss associated with exercise should not undermine its capacity to improve health. health professionals, it can be argued, have a responsibility to promote exercise, publicise the health benefits independent of body weight and, more importantly, shift the focus from changes in body weight to changes in overall physical and psychological well-being. our intervention study has clearly demonstrated that when exercise is carried out, people experience beneficial physiological and psychological effects independent of any effect on body weight. however, the implication of these results for weight management and the obesity epidemic should be interpreted carefully. the results do not mean the exercise is fruitless or ineffective in the battle against obesity. overall, exercise can help to check weight gain, and in some people it is very effective. others need additional help to deal with any compensatory response. funding: this study forms part of a larger project funded by the biotechnology and biological sciences research council (bbs/ b/05079). competing interests: none. ethics approval: ethics approval was provided by university of leeds ethics committee. patient consent: obtained. provenance and peer review: not commissioned; not externally peer reviewed. references 1. campos p, saguy a, ernsberger e, et al. the epidemiology of overweight and obesity: public health crisis or moral panic? int j epidemiol 2005;35:55–60. 2. rigby n. commentary: counterpoint to campos et al. int j epidemiol 2005;35:79–80. 3. garrow js, summerbell cd. meta-analysis: effect of exercise, with or without dieting, on the body composition of overweight subjects. eur j clin nutr 1995;49:1–10. 4. king na, hopkins m, caudwell p, et al. involuntary and voluntary compensatory responses to exercise interventions: barriers to weight loss. obesity 2007;15:1373–83. 5. king na, caudwell p, hopkins m, et al. individual variability following 12 weeks of supervised exercise: identification and characterisation of compensation for exerciseinduced weight loss. int j obes rel met dis 2007;32:177–84. 6. foster gd, wadden ta, vogt ra, et al. what is a reasonable weight loss? patients expectations and evaluations of obesity treatment outcomes. j con clin psych 1997;65:79–85. 7. blair sn, lamonte mj. commentary: current perspectives on obesity and health: black and white, or shades of grey? int j epidemiol 2005;35:69– 72. 8. janssen i, katzmarzyk pt, ross r. waist circumference and not body mass index explains obesity-related health risk. am j clin nutr 2004;79:379–84. 9. poirier p, lemieux i, mauriege p, et al. impact of waist circumference on the relationship between blood pressure and insulin: the quebec health survey. hypertension 2005;45:363–7. 10. janiszewski pm, janssen i, ross r. does waist circumference predict diabetes and cardiovascular disease beyond commonly evaluated cardio metabolic risk factors? diab car 2007;30:3105–9. 11. ross r, janiszewski. is weight loss the optimal target for obesity-related cardiovascular disease risk reduction? can j cardiol 2008;24:25d–31d. 12. teixeira pj, going sb, sardinha lb, et al. a review of psychosocial pretreatment predictors of weight control. obes rev 2005;6:43–65. 13. teixeira pj, going sb, houtkooper lb, et al. exercise motivation, eating, and body image variables as predictors of weight control. med sci sports exerc 2006;38:179–88. 14. van gaal lf, wauters ma, de leeuw ih. the beneficial effects of modest weight loss on cardiovascular risk factors. int j obes rel met dis 1997;21:s5–s9. 15. blair sn, kohl hw 3rd, barlow ce, et al. changes in physical fitness and all-cause mortality. a prospective study of healthy and unhealthy men. jama 1995;273:1093–8. 16. blair sn. physical inactivity: the biggest public health problem of the 21st century. br j sprt med 2009;43:1–2. 17. snyder ka, donnelly je, jabobsen dj, et al. the effects of long-term, moderate intensity, intermittent exercise on aerobic capacity, body composition, blood lipids, insulin and glucose in overweight females. int j obes relat metab disord 1997;21:1180–9. 18. donnelly je, smith bk. is exercise effective for weight loss with ad libitum diet? energy balance, compensation, and gender differences. exerc sport sci rev 2005;33:169–74. 19. mayer j, roy p, mitra kp. relation between caloric intake, body weight, and physical work: studies in an industrial male population in west bengal. am j clin nutr 1956;4:169–74. 20. watson d, clark la, tellegen a. development and validation of brief measures of positive and negative affect: the panas scales. j person soc psychol 1998;54:1063–70. 21. leibel rl, rosenbaum m, hirsch j. changes in energy expenditure resulting from altered body weight. n engl j med 1995;332:621–8. 22. katzmarzyk pt, janssen i, ross r, et al. the importance of waist circumference in the definition of metabolic syndrome: prospective analyses of mortality in men. diab car 2006;29:404–9. 23. klein s, allison db, heymsfield sb, et al. waist circumference and cardio metabolic risk: a consensus statement from shaping america’s health: association for weight management and obesity prevention; naaso, the obesity society; the america society for nutrition; and the american diabetes. diab care 2007;30:1647–52. 24. dekker mj, lee s, hudson r, et al. an exercise intervention without weight loss decreases circulating interleukin-6 in lean and obese men with and without type 2 diabetes mellitus. metab 2007;56:332–8. 25. blumenthal ja, sherwood a, gullette ec, et al. exercise weight loss reduce blood pressure in men with mild hypertension: effects on cardiovascular, metabolic and hemodynamic functioning. arch intern med 2000;160:1947–58. 26. tuomilehto j, lindstrom j, eriksson jg, et al. prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. n engl j med 2001;344:1343–50. 27. janiszewski pm, ross r. physical activity in the treatment of obesity: beyond body weight reduction. appl physiol nutr metab 2007;32:512– 22. 28. church ts, earnest cp, skinner js, et al. effects of different doses of physical activity on cardiorespiratory fitness among sedentary, overweight or obese postmenopausal women with elevated blood pressure: a randomized controlled trial. jama 2007;297:2081–91. 29. caudwell p, hopkins m, king na, et al. exercise alone is not enough; weight loss also needs a healthy (mediterranean) diet. pub health nutr 2009;12:1663–6. 30. king n, caudwell p, hopkins m, et al. dual process action of exercise on appetite control: increase in orexigenic drive but improvement in mealinduced satiety. am j clin nutr 2009;90:921–7. 58 sajsm vol. 27 no. 2 2015 case study the clinical presentation of a missed posterior shoulder dislocation has similarities with an idiopathic frozen shoulder masking proper diagnosis at the time of injury. we report a case of a 48-year-old woman with shoulder pain which demonstrates the importance of correct initial diagnosis and management. s afr j sports med 2015;27(2):58-59. doi:10.7196/sajsm.613 frozen shoulder or missed posterior dislocation? d leijnen,1,2 md, mmed (sports med); j t viljoen,1 bsc (physio), mphil (exercise sci); j h kirby,1 mb chb, msc (sports med); p l viviers,1 mb chb, mmed sc, msc (sports med) 1 campus health service and the centre for human performances sciences, stellenbosch university, stellenbosch, south africa 2 department of physical medicine and rehabilitation, catholic university of leuven, leuven, belgium corresponding author: p l viviers (plv@sun.ac.za) the glenohumeral (gh) joint consists of the humeral head that articulates in the glenoid fossa of the scapula, surrounded by several static and dynamic structures. it is the most mobile joint of the human body which makes it vulnerable to dislocation in all directions. posterior shoulder dislocation (psd) is less common than anterior. the rarity of this pathology together with the restrictions of standard view x-rays often leads to the diagnosis being missed. case report a 48-year-old woman presented with 4 months of spontaneous progressive pain and limited range of motion of the right shoulder. her pain was aggravated by movement and impacts, particularly those activities associated with daily living. she was unable to lie on her right side but did not complain of any pain at night. she had no history of trauma although she recently started experiencing episodes of syncope. further to this, her medical history consisted of hypertension, hypercholesterolaemia, asthma and previous left frozen shoulder. upon clinical examination she held the right upper limb in internal rotation with the elbow in flexed position. there was diffuse, mild tenderness over the anterolateral side of the shoulder. range of motion was limited to 5 degrees of passive and active abduction. external rotation was not possible. other shoulder tests were impossible to implement. x-rays showed normal proportions of the gh joint with the humeral head articulating in the glenoid. on the anterior side of the humeral head a medium sized dent was visible, suggestive of a reverse hill-sachs lesion. the differential diagnosis was an overlooked posterior shoulder dislocation or adhesive capsulitis. discussion psd is a rare entity. incidence is approximately 2 5% of all shoulder dislocations.[1] most often psd is the result of an epileptic seizure. less frequent causes are seizures due to alcoholic withdrawal or other metabolic disorders, electrocution or during a high-energy trauma. in this particular scenario we suspected that psd likely occurred as a result of an episode of syncope. according to the literature, psd is frequently overlooked at the time of injury or may stay clinically undetectable, which makes the real incidence unsure.[2] a missed diagnosis of posterior shoulder dislocation at the time of injury could lead to an incorrect diagnosis of frozen shoulder at a later stage. shoulder stability is provided by static and dynamic structures. posterior static stabilisers of the glenoid are the labrum, the posterior capsule and the posterior band of the inferior gh ligament. dynamic structures are the shoulder girdle muscles and the rotator cuff. traumatic psd occurs when a high axial loading force is applied to the upper extremity in the vulnerable position of internal rotation, adduction and forward elevation. in an involuntary contraction, the strong internal rotators overpower the weak external rotators. the injured extremity is held in internal rotation with the loss of external rotation as the cardinal sign. clough and bale[3] recommend an axillary view of the shoulder if psd is suspected. an axillary view is taken by gentle abduction of the shoulder to 20 30° with the x-ray tube at the level of the hip and the cassette at the shoulder. if a true axillary view cannot be taken, usually because it is too painful for the patient, a velpeau or wallace view (modified axillary views) is advised. psd is regularly accompanied by associated injuries. a fracture of the humeral neck can displace during reduction. the humeral head has a segmental blood supply; if the ascending branch of the arterial humeral circumflex artery is compromised there is a risk for osteonecrosis.[2,4] other possible fractures involve the greater and lesser tuberosities, posterior rim fracture, or combinations thereof. the most important one is probably the pathognomonic lesion in the humeral head, the reverse hill-sachs lesion or encoche fracture. kowalsky and levine[1] describe the significance of the humeral head defect as being threefold: it serves as a propagation point which makes the proximal humerus susceptible to fractures of the anatomic neck, it makes the gh joint susceptible to secondary osteoarthritis, and the size of the impression defect determines the stable arc of curvature of the gh articulation. the size of the humeral head impression also has a critical role in the determination of the optimal treatment strategy, as discussed later. rotator cuff tear injuries are present in 13%.[5] less frequent associated injuries are brachial plexopathy and axillary nerve palsy.[6] to date, because of the lack of high-level evidence, there are no sajsm vol. 27 no. 2 2015 59 definitive management guidelines for psd. an attempt at gentle closed reduction is generally advised if an isolated psd is less than 6 weeks and the humeral head impression is less than 25% of the articular surface. in chronic psd, or if the humeral head impression exceeds 25% of the articular surface, different operative treatment strategies are described, namely the mclaughlin procedure, modified mclaughlin procedure or a rotation osteotomy of the humerus and reconstruction of the humeral head impression with the use of autoor allograft. in large defects exceeding more than 50% of the articular surface of the humeral head or secondary osteoarthritis, an arthroplasty is suggested as being the optimal treatment strategy.[7] owing to the risk of posterior subluxation due to anterior-inferior and subscapularis contractures, an insertion of the prosthesis is made in relatively anteverted orientation, or normal prosthetic retroversion with anterior capsular release. in psd with the rarer complex fractures of the proximal aspect of the humerus, there have been favourable functional results with the use of open relocation, fracture reduction and stabilisation, and adjuvant stabilisation procedure if necessary in 28 cases.[8] in these complex fracture-dislocations, the majority of the functional loss in the long-term was attributable to loss of internal rotation of the shoulder. long-term complications include recurrent instability, osteonecrosis and post-traumatic shoulder stiffness. in a retrospective review of 120 acute, traumatic, isolated posterior gh dislocations robinson et al.[9] found three factors that were significantly associated with an increased risk of recurrent instability: an age <40 years at the time of original dislocation, dislocation during a seizure and the presence of a reverse hill-sachs lesion >1.5 cm3. therefore, if a redislocation occurs, an additional adjunctive stabilisation procedure is recommended. the same study also underscores the risk for post-traumatic shoulder stiffness after reduction in case of postponed diagnosis, which is probably due to peri-articular fibrosis and capsular contractures. conclusion this case report demonstrates the importance of taking a proper medical history to rule out syncope as a possible means of trauma giving rise to psd. also, while posterior dislocation of the shoulder is generally known among sports medicine practitioners, it is often unrecognised which could lead to the incorrect diagnosis of idiopathic frozen shoulder at a later stage. diagnosis is primarily based on initial clinical findings and a high index of suspicion after seizure, electrocution or high-energy trauma. one should be aware of associated injuries, especially humeral neck fractures, before attempts for reduction are made. in chronic cases, differential diagnosis includes idiopathic frozen shoulder and a surgical approach is mainly recommended. post reduction long-term complications involve recurrent instability, osteonecrosis and post-traumatic shoulder stiffness. references 1. kowalsky ms, levine wn. traumatic posterior glenohumeral dislocation: classification, pathoanatomy, diagnosis, and treatment. orthop clin north am 2008;39(4):519-533. [http://dx.doi.org/10.1016/j.ocl.2008.05.008] 2. robinson cm, aderinto j. posterior shoulder dislocations and fracturedislo cations. j b one joint surg am 2005;87(3):639-650. [http://dx.doi. org/10.2106/jbjs.d.02371] 3. clough tm, bale rs. bilateral posterior shoulder dislocation: the importance of the axillary radiographic view. eur j emerg med 2001;8(2):161-163. 4. hersche o, gerber c. iatrogenic displacement of fracture-dislocations of the shoulder: a report of seven cases. j bone joint surg br 1994;76(1):30-33. 5. rouleau dm, hebert-davies j. incidence of associated injury in posterior shoulder dislocation: systematic review of the literature. j orthop trauma 2012;26(4):246-251. [http://dx.doi.org/10.1097/bot.0b013e3182243909] 6. bhatia dn, de beer jf, van rooyen ks, du toit df. the reverse terrible triad of the shoulder: circumferential glenohumeral musculoligamentous disruption and neurologic injury associated with posterior shoulder dislocation. j shoulder elbow surg 2007;16(3):13-17. [http://dx.doi.org/10.1016/j.jse.2006.07.013] 7. rouleau dm, hebert-davies j, robinson cm. acute traumatic posterior shoulder dislocation. j am acad orthop surg 2014;22(3):145-152. [http://dx.doi.org/10.5435/ jaaos-22-03-145] 8. robinson cm, akhtar a, mitchell m, beavis c. complex posterior fracturedislocation of the shoulder: epidemiology, injury patterns, and results of operative treatment. j bone joint surg am 2007;89(7):1454-1466. [http://dx.doi.org/10.2106/ jbjs.f.01214] 9. robinson cm, seah m, akhtar ma. the epidemiology, risk of recurrence, and functional outcome after an acute traumatic posterior dislocation of the shoulder. j bone joint surg am 2011;93(17):1605-1613. [http://dx.doi.org/ 10.2106/ jbjs.j.00973] original research 60 sajsm vol 24 no. 2 2012 introduction in south africa physical inactivity presents a challenge that must be addressed urgently since an excessively high proportion (50%) of south africans are currently living sedentary lives.1 inactivity in adults increases the risk of non-communicable diseases, and because these are chronic diseases of lifestyle they negatively affect quality of life.2,3 for sedentary individuals, participation in moderate-intensity physical activity is advisable because such activity would reduce the risk of coronary heart disease (chd) and have substantial healthrelated fitness benefits; not only those associated with obesity, but also the reduction of blood pressure, improved levels of high-density lipoproteins and the control of blood glucose in overweight people, even without significant weight loss, and a reduction in the risk of colon cancer and, among women, breast cancer.3,4 therefore sedentary adults need to be persuaded to exercise regularly at a moderate intensity.2,5 the challenge however is to overcome barriers related to exercise participation, including lack of compliance, poor weather conditions, time constraints, work obligations, and low levels of motivation, confidence and self-esteem.6 the use of whole body vibration (wbv) as an exercise intervention for health promotion among sedentary adults is increasingly being considered among health professionals because, compared with conventional training methods, it offers a way of training with practical, physical and psychological advantages. wbv is a current neuromuscular training method, which even at a low intensity provokes muscle length changes that stimulate the sensory receptor of the muscle spindle, thereby eliciting a tonic vibratory reflex, which is defined as a sustained contraction of a muscle subjected to vibration. wbv intervention exploits the body’s innate reflex response to disruptions in stability in order to stimulate and enhance muscle strength and performance. practically, wbv training has the advantage of overcoming some of the cited obstacles to exercise because it decreases overall training time and takes place indoors. more importantly, it offers a host of physical benefits such as improved muscular strength, flexibility, range of motion, bone density, and improved blood circulation.7 in addition, wbv heightens confidence, which encourages ongoing participation and programme adherence.2,8 given these advantages, a wbv exercise programme, if individually structured and supervised, provides an attractive mode of training for sedentary individuals. the purpose of this investigation is to determine the effectiveness of wbv training in enhancing the following components of health-related physical fitness in sedentary individuals: body mass, hamstring flexibility, upper-body strength and abdominal and upper-body muscular endurance. methods a quasi-experimental approach using a two-group comparison, pre and post-test design, was utilised to compare the responses of the experimental and control group over a 12-week intervention period for selected health-related physical fitness parameters of measures of body mass, hamstring flexibility, grip strength, and abdominal and upper-body muscle endurance.7 a non-randomised sampling technique8 was used with an equivalent match-pair design to divide the base of volunteers gathered through a combination of accidental and snowball sampling into either the experimental (n=32) or control group (n=30). the match-pair design was used to ensure that the dynamics within the experimental and control groups were uniform prior to the wbv intervention. in order to match individuals, each participant received a composite score after completing the healthrelated physical fitness evaluation at the pre-test. participants with the same or similar composite scores were then allocated to either the experimental or control group. each group therefore resembled aayesha kholvadia, maryna l baard department of human movement science, nelson mandela metropolitan university, port elizabeth aayesha kholvadia, ma human movement science (biokinetics) maryna l baard, dphil corresponding author: m l baard (maryna.baard@nmmu.ac.za). whole body vibration improves body mass, flexibility and strength in previously sedentary adults abstract objectives. this study aimed to determine the effectiveness of whole body vibration (wbv) training for promoting healthrelated physical fitness in sedentary adults. design. a non-randomised sampling technique was used with an equivalent match-pair comparison group, preand posttest design. volunteers were gathered through a combination of accidental and snowball sampling and divided into either the experimental (n=32) or control group (n=30). dependent variables included body mass, hamstring flexibility as measured by the sit-and-reach test, upper-body strength as measured by a grip strength dynamometer, abdominal and upper-body muscular endurance as measured by 1-minute timed sit-up and push-up tests, respectively. the standardised ymca fitness battery was used as the evaluation protocol. the wbv experimental group participated in a progressive 3 times/week training programme for a maximum duration of 30 minutes/session for 12 consecutive weeks. the control group remained sedentary. results. significant improvements in all five of the selected dependent parameters were measured. conclusion. wbv training 3 times weekly for 30 minutes/ session provides an effective method of exercise intervention for health promotion in sedentary adults over a 12-week period. s afr j sm 2012;24(2):60-64. sajsm vol 24 no. 2 2012 61 the other in as many parameters as possible.9,10 the nelson mandela metropolitan university (nmmu) research human ethical committee gave ethical approval. the exercise intervention occurred 3 times a week for 12 consecutive weeks. data-gathering techniques prospective participants were informed of the study by electronic mail, highlighting the rationale of the study and specifying the inclusion criteria as being sedentary for a period of 6 months. exclusion criteria were clearly defined because of the possible contraindications outlined by the power plate® manufacturers. all nmmu staff were invited to participate in the study on a voluntar y basis. table 1 indicates descriptive data about the participants. prior to measurement of the dependent variables, a health risk assessment was done by screening for chd risk factors as measured by the physical activity readiness questionnaire (par-q). this was done to ensure safe participation in the 12week intervention programme. the dependent variables included body mass, hamstring flexibility as measured by the sit-andreach test, upper-body muscle strength as measured by a grip strength dynamometer, and abdominal and upper-body muscle endurance as measured by 1-minute timed sit-up and push-up tests, respectively. the well-known standardised ymca fitness battery2 was used as the evaluation protocol for both the pre-test and post-test assessments for both groups. the following procedure was employed: written consent was obtained from each participant prior to the study; clinical data were gathered; pre-test measurements were applied for the dependent variables; the wbv intervention programme was implemented (or a sedentary lifestyle was maintained for the control group) for a 12week period; the post-test measurement concluded the programme. intervention programme wbv training, in the form of static exercises, was performed on the vibration platform (power plate®) by the experimental group, while the control group remained sedentary throughout the 12week intervention period. the experimental group trained with progressive increments in either the intensity (amplitude of the vibration) or duration resulting in an increase in the total length of the particular exercise session. training intensity was manipulated by either increasing the amplitude of the vibration from low (l) to high (h), or by manipulating the intensity of the training between 30 hz and 50 hz. manipulation of either the total duration of the time spent on the vibration platform or the total duration of the exercise session was used to indicate the training progression. the training frequency was set at three training sessions per week. aforementioned variables in the wbv intervention programme are displayed in table 2. the programme design is based on the guidelines for training principles as prescribed by the american college of sports medicine (acsm).11 statistical analysis the statistica version 9.0 computer processing package (statsoft, inc, tulsa, ok, usa) was used to analyse the data and the level of significance was set at p<0.05. for the comparisons involving the wbv experimental and sedentary control group, descriptive measures of means and standard deviations (sds) were calculated. independent t-tests and χ2 tests were performed to determine statistically significant intergroup differences at the preand post-tests for all selected dependent variables. cohen’s d-values were calculated to express the level of practical significance. the interpretation of cohen’s d-values is as follows: d=0.20, 0.50 and 0.80, respectively, indicate small, medium and large effects in practical significance.10,12 table 1. description of participants experimental group control group number of participants at the beginning of the study, n 42 30 age of participants (range), years 19 52 17 54 gender delineation of participants 21 males, 21 females 15 males, 15 females number of participants at the end of the study, n 32 30 dropout rate, % 24 0 table 2. wbv training variables training intensity training duration training type session (week) amplitude hz per exercise (s) total session duration (h:min:s) type of exercise 1 l 30 30 0:00:10 general: calf raise, lunge, abductor, adductor squeeze, squat upper-body strength: push-up, bicep curl, side raise, tricep pull, tricep dip hamstring flexibility: hamstring stretch, quadriceps stretch, calf stretch core: frontal bridge, side bridge, sit-ups 2 l 30 45 0:12:30 3 l 30 60 0:21:00 4 h 30 45 0:17:15 5 h 30 45 0:17:15 6 h 35 45 0:19:30 7 h 40 45 0:20:30 8 h 50 45 0:20:15 9 h 30 60 0:30:00 10 h 35 60 0:30:00 11 h 40 60 0:30:00 12 h 50 60 0:30:00 62 sajsm vol 24 no. 2 2012 results body mass as shown in table 3, a decrease in body mass (kg) for the experimental group was measured, with a pre-test mean of 74.5 kg and a post-test mean of 73.4 kg. the mean body mass for the control group ranged from 74.6 kg to a post-test value of 74.9 kg. the experimental group showed a decrease of 1.1 kg in the mean body mass whereas the control group showed an increase of 0.3 kg. no statistical significance was achieved as indicated by t=0.10, p<0.05 and χ2=12.23, p<0.05 for this component of body composition. furthermore, moderate practical significance was indicated by cohen’s d=0.60. these results are reflected in table 3. a graphical representation of all five dependent variables based on the rank order of the mean preand post-test differences is displayed in fig. 1. hamstring flexibility as shown in table 3, a significant increase in hamstring flexibility was measured for the experimental group, with a pre-test mean of 22.5 cm and a post-test mean of 27.3 cm. hamstring flexibility for the control group ranged between 27.1 cm and 26.2 cm for both the preand post-test analyses. the mean hamstring flexibility for the experimental group showed a statistically significant increase with t=-5.31, p<0.05 and χ2=23.31, p<0.05 after the 12-week intervention. large practical significance was indicated by cohen’s d=1.35 as shown in table 3. muscle strength grip strength table 3 reflects a significant increase in the grip strength values for the experimental group, with a pre-test mean of 41.0 kgf and a post-test mean of 47.1 kgf. the experimental group showed a mean increase in grip strength by 6.1 kgf whereas the control group showed a mean decrease of 0.4 kgf having a pre-test mean value of 47.8 kgf and a post-test value of 47.3 kgf. grip strength for the experimental group showed a statistically significant increase with t=4.67, p<0.05 and χ2=22.94, p<0.05 after the 12week intervention. large practical significance was indicated by cohen’s d=1.19 as indicated in table 3. muscular endurance abdominal muscular endurance table 3 reflects a significant increase in abdominal muscular endurance for the experimental group, with a pre-test mean of 33 repetitions and a post-test mean of 37 repetitions. abdominal muscular endurance for the control group was 25 repetitions for both the preand post-tests. the mean muscular endurance values for the experimental group showed a statistically significant increase with t=4.12, p<0.05 and χ2=30.06, p<0.05 after the 12-week duration of the study. large practical significance was indicated by cohen’s d=1.0 as shown in table 3. table 3. preand posttest results based on mean differences of the selected five dependent variables for both groups measurement group pre post post-pre difference body mass (kg) control (n=30) 74.6±13.7 74.9±13.8 0.3±1.4 wbv (n=32) 74.5±19.0 73.4±18.4 -1.1±2.7 difference -0.1 1.5 1.4 t-test; p-value effect size -0.02; 0.985 n.a. 0.36; 0.719 n.a. 0.76; 0.507 n.a. hamstring flexibility (cm) control (n=30) 27.15±11.30 26.29±11.16 -0.87±1.84 wbv (n=32) 22.53±11.41 27.32±7.86 4.79±5.56 difference 4.60 -1.10 -5.66 t-test; p-value effect size 1.59; 0.116 n.a. -0.45; 0.652 n.a. -5.31; 0.0001 1.35 large grip strength (kgf ) control (n=30) 47.8±25.2 47.3±23.9 -0.5±6.0 wbv (n=32) 41.0±18.8 47.2±18.7 6.2±5.2 difference 6.8 0.2 -6.6 t-test; p-value effect size 1.21; 0.229 n.a. 0.04; 0.971 n.a. -4.67; 0.0001 1.19 large abdominal muscle endurance (reps) control (n=30) 25±13 25±14 0±2 wbv (n=32) 33±10 37±9 4±7 difference 8 -12 -5 t-test; p-value effect size 0.24; 0.810 n.a. -3.76; 0.000 0.95 large -4.12; 0.0001 1.05 large upper body muscle endurance (reps) control (n=30) 20±13 19±12 -1±2 wbv (n=32) 24±12 33±14 9±7 difference -4 -14 -10 t-test; p-value effect size -1.40; 0.166 n.a. -3.90; 0.000 0.99 large -6.88; 0.000 1.75 large wbv = whole body vibration; n.a. = no effect as p>0.05; reps = repetitions. sajsm vol 24 no. 1 2012 63 upper-body muscular endurance table 3 reflects that upper-body muscular endurance of the experimental group improved as the mean number of push-ups performed increased by 9 repetitions with preand post-test values being recorded as 24 and 33 respectively with t=-6.88, p<0.05 and χ2=29.47, p<0.05 after the 12-week study. conversely, the control group exhibited a decrease of 1 repetition over the entire intervention period. the mean number of push-ups for the pre-test was 20 repetitions for the control group. posttest analysis revealed a range of 1 45 repetitions for the control and 15 72 repetitions for the experimental group. large practical significance was indicated by cohen’s d=1.7. discussion the results indicate a significant improvement in body composition that consisted of a reduction in body mass by 2.7% in a relatively short period of 12 weeks (<6 months). evidence from several metaanalyses13,14 indicates that weight reduction programmes based purely on increasing levels of physical activity alone are not very successful (a typical loss of 0.3 1.3 kg over 16 weeks). the authors conclude that achieving long-term weight loss via exercise alone is rare and, together with updated recommendation for adults,15,16 propose that regular physical activity of moderate intensity for 60 min/day combined with caloric restriction is the most successful long-term weight management strategy.17 it should be noted that the stated optimum training time for a positive consequential effect on body composition is 60 90 min/day. however, this study showed that wbv training provided sufficient levels of exercise for this purpose in 30 min 3x/ week. this decrease in overall training time shows that wbv training is effective in overcoming time constraints as a practical barrier to exercise. the long-term maintenance of weight reduction as a result of wbv training needs to be established. the significant improvement in hamstring flexibility in the experimental group could be explained by two possible mechanisms. firstly, the enhanced local blood flow through the muscles generated additional heat, thereby enhancing muscle elasticity and facilitating an increase in range of motion in the hamstring muscles. the second mechanism proposed is neurophysiological in nature as the vibration training elicited a tonic vibration reflex that activated the muscle spindles and led to the advancement of the stretch-reflex loop.18,19 significant increases in upper-body muscle strength (as measured by grip strength) by using wbv training were in agreement with findings that have previously been reported for training-induced strength gains. muscular strength scores for absolute grip strength increased by 87% over the intervention period as compared with those of their sedentary counterparts.20,21 this substantial increase in muscular strength plays an important role in health promotion, fig. 1. observations of all five selected dependent variables based on ranked differences by group. 64 sajsm vol 24 no. 2 2012 as it is associated with lean muscle mass and may promote better compliance with activities of daily living as laid out in the world health organization’s global strategy on diet, physical activity and health.22-24 it could be argued that wbv training stimulated resting metabolic rate which contributes about 60 70% of daily energy expenditure and increased fat-free mass which is the main contributor to resting metabolism. evidence shows that resistance exercises may produce a moderate increase in fat-free mass and a reduction in cardiovascular disease risk factors for some individuals independent of weight loss.16 the findings regarding abdominal and upper-body muscle endurance are in agreement with previous findings20,21 regarding an improvement in abdominal endurance after a 12-week wbv therapy programme in previously sedentary individuals. delecluse et al.21 reported that vibratory waves irritated the primary endings of the muscle spindle that activated a larger fraction of the motor neuron pool and recruited previously inactive motor units into contraction. this resulted in a more efficient use of the force production potential of the muscle groups involved. this mechanism of motor neuron pool activation was further reinforced during wbv by the recruitment of previously inactive motor neurons, together with their activity synchronisation, and increased discharge of the neural drive, which led to greater improvements in neuromotor control during voluntary muscle contraction as evaluated in the modified sit-up and push-up assessments, respectively. conclusion although the study was conducted on a relatively small sample group over a period of 12 weeks only, it provides useful information that indicates that wbv training appears to be a safe exercise modality when structured and supervised by a health professional to enhance health-related physical fitness in sedentary adults. thus, there is evidence to support the use of wbv training by healthcare professionals and exercise scientists as a means to increase selected health-related physical fitness variables in sedentary individuals. based on these results, it could be concluded that wbv training provides an effective method of exercise intervention to overcome barriers in becoming physically active and for health promotion in previously sedentary individuals. however, further research is needed to determine the long-term effects of wbv as exercise intervention for promoting healthrelated physical fitness in sedentary individuals, together with more direct measures of training adaptation such as heart rate and maximal oxygen uptake (vo2 max). limitations and recommendations for future research there is a need for further investigation into the long-term positive and negative effects of wbv therapy on the health-related components of physical fitness of anthropometrical profile, muscular flexibility, muscular strength, muscular endurance and aerobic capacity. in addition, direct anthropometrical analyses of changes in fat mass and lean muscle mass ratios after using wbv therapy as a training modality need to be addressed. further research is also required in respect of the activation of core musculature during wbv therapy, since lower back pain was identified as a major debilitating factor in the wellness profile of adults during this study. study designs and exercise programme prescriptions should also be implemented to explore and describe the effects of wbv therapy on aerobic capacity. pre-set heart rate requirements should be based on age-adjusted maximal heart rate values to guide the exercise programme design and prescription. acknowledgement. financial assistance was received from the national research foundation (nrf) and the nmmu as a research grant. references 1. statistics south africa: statistical release p0211.2. monthly earnings of south africans, 2010. 2. hoeger wk, hoeger sa. lifetime physical fitness and wellness: a personalised program. 12th ed. stanford: wadsworth cengage learning, 2013. 3. coburn jw, malek mh. nsca’s essentials of personal training. 2nd ed. champaign, il: human kinetics, 2012. 4. blair sn, cheng y, holder js. is physical activity or physical fitness more important in defining health benefits? med sci sports exerc 2001;33:s379-399. 5. physical activity guidelines and introduction. centers for disease control. http://www. cdc.gov/physicalactivity/everyone/guidelines/adults.html (accessed 13 july 2011). 6. rittweger j, beller g, felsenberg d. acute physiological effects of exhaustive whole body vibration exercise in man. clin phys 2000;20:134-142. 7. delecluse c, roelants m, diels r, koninckx e, verschueren s. effects of whole body vibration training on muscle strength and sprint performance in sprint-trained athletes. int j sports med 2004;26:662-668. 8. de vos as, strydom h, fouché cb, delport csl. research at grassroots for the social sciences and human service professions. 3rd ed. pretoria: van schaik, 2009: 140-208. 9. myers j. fundamentals of experimental design. 2nd ed. new york: allyn & bacon, 1998:104-120. 10. thomas jr, nelson jk. research methods in physical activity. 3rd ed. champaign, il: human kinetics; 1996. 11. donnely je, blair sn, jackicic jm. american college of sports medicine position stand. appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. med sci sports exerc 2009;41:459-471. 12. anderson dr, sweeney dj, william ta. modern business statistics with microsoft excel. stanford: cengage learning, 2003. 13. macfarlane dj, thomas gn. exercise and diet in weight management: updating what works. south african journal of sports medicine 2011;23(2):57-61. 14. bull fc, pratt m, shephard rj, lankenau b. implementing national based action on physical activity – challenges for action and opportunities for international collaboration. int j health promot educ 2006;13(2):127-132. 15. wing rr. physical activity in the treatment of adulthood overweight and obesity: current evidence and research issues. med sci sports exerc 1999;31:s547-552. 16. volek js, vanheest jl, forsythe ce. diet and exercise for weight loss: a review of current issues. sports med 2005;35;1-9. 17. jakicic jm, clark k, coleman e. american college of sports medicine position stand. appropriate intervention strategies for weight loss and prevention of weight regain for adults. med sci sports exerc 2001;33:2145-2156. 18. carlsoo s. the effect of vibration on the skeleton, joints and muscles: a review of literature. appl ergon 1982;13:251-258. 19. eklund g, hagbarth ke. normal variability of the tonic vibration reflex in man. exp neurol 1966;16:80-92. 20. delecluse c, roelants m, verschueren s. strength increase after whole body vibration compared with resistance training. med sci sport exerc 2003;35:1033-1041. 21. delecluse c, roelants m, diels r, koninckx e, verschueren s. effects of whole body vibration training on muscle strength and sprint performance in sprint-trained athletes. int j sports med 2006;26:662-668. 22. world health organization. who global strategy on diet, physical activity and health: african regional consultation meeting report. harare, zimbabwe, 18-20 march 2003. 23. world health organization. preventing chronic diseases: a vital investment. geneva. fifty-seventh world health assembly [wha 57.17] held on 24 may 2004. agenda item 12.6 for discussion on ‘global strategy on diet, physical activity and health’, 2004. 24. world health organization. reducing risks, promoting healthy life. the world health report. geneva. fifty-seventh world health assembly [wha 57.17] held on 24 may 2004. agenda item 12.6 for discussion on ‘global strategy on diet, physical activity and health’, 2004. 1. true (a) or false (b) – click on the correct answer: chronic low back pain is uncommon and only affects about 25% of the population. 2. true (a) or false (b) – click on the correct answer: chronic low back pain costs the economy of south africa several billion rand every year. 3. true (a) or false (b) – click on the correct answer: whole body vibration therapy appears to be a safe, rehabilitative exercise modality that improves lower back and hamstring flexibility, increases relative back strength and increases abdominal muscular endurance in patients with chronic low back pain. 4. true (a) or false (b) – click on the correct answer: the actual risk of sustaining a catastrophic injury while playing rugby is low in comparison to other sports (diving and horse-riding) and even everyday activities (driving or walking to work). 5. true (a) or false (b) – click on the correct answer: boksmart was a programme designed by danie craven to improve the tactical acumen of high-level rugby players. 6. true (a) or false (b) – click on the correct answer: in the usa, the obesity prevalence rates (body mass index >30) have increased 10-fold between 1986 and 2000. 7. true (a) or false (b) – click on the correct answer: in the uk, the adult overweight/obesity rates are just over 60%. 8. true (a) or false (b) – click on the correct answer: the long-term success of most weight management programmes has been disappointing, with only 30% of the programmes successfully maintaining a loss >10% of body weight for >5 years. 9. true (a) or false (b) – click on the correct answer: long-term weight loss is difficult to achieve, with most individuals typically regaining 70 80% of their lost weight. 10. true (a) or false (b) – click on the correct answer: enhancing metabolic fitness to control hypertension, dyslipidaemia and hyperglycaemia indirectly lowers the risk of cardiovascular disease. 11. true (a) or false (b) – click on the correct answer: exercise alone is the most effective method for achieving long-term weight loss. 12. true (a) or false (b) – click on the correct answer: the female athlete triad, described in 1992, consists of disordered eating, amenorrhoea, and hypertension. 13. true (a) or false (b) – click on the correct answer: a contemporary description of the female athlete triad defines it as consisting of energy availability, menstrual function and bone mineral density. 14. true (a) or false (b) – click on the correct answer: forty-two per cent of the participants at the most recent summer olympics in beijing (2008) were females. 15. true (a) or false (b) – click on the correct answer: studies show that the per cent of female athletes with low bone mineral density ranged from 0% to 50%. 16. true (a) or false (b) – click on the correct answer: the risk for the components of the female athlete triad increases as the level of competition decreases (i.e. elite athletes, collegiate athletes and recreational athletes). 17. true (a) or false (b) – click on the correct answer: it should be emphasised to athletes that menstrual dysfunction is a normal response to athletic training. 18. true (a) or false (b) – click on the correct answer: cricket bowlers have the highest risk of injury compared to the other cricket players. 19. true (a) or false (b) – click on the correct answer: most of the injuries sustained by cricket players during a season are old recurrent injuries. 20. true (a) or false (b) – click on the correct answer: the risk of developing hypercholesterolaemia and coronary heart disease in females decreases exponentially after menopause. questions june 2011 c p d q u e s t io n n a ir e cpd questionnaires must be completed online via www.cpdjournals.co.za. after submission you can check the answers and print your certificate. questions may be answered up to 6 months after publication of each issue. instructions 1. read the journal. all the answers will be found there. 2. go to www.cpdjournals.co.za to answer questions. accreditation number: mdb001/008/01/2011 (clinical) sajsm original research sajsm vol 24 no. 2 2012 43 introduction south african children are showing trends of obesity and overweight, similar to values reported from high-income countries 15 years ago.1 the decline in overall physical activity (pa) levels has occurred concomitantly with the rising trend of obesity,2 and less than onethird of south african children now participate in sufficient (defined as participation in activities such as soccer, netball, rugby, basketball or running for 20 minutes or more on at least 3 of the 7 days preceding the survey) pa on a weekly basis.3 4 there is an ethnic disparity regarding levels of pa in south african children, with a greater percentage of black youths (37.5%) found to be insufficiently active compared with white youths (29.4%). moreover, less than one-third of 9-year-old black south african children report having structured physical education classes at school.5 this coupled with evidence for declining pa levels with increasing age is concerning.6 accelerometers that measure body movement in terms of acceleration are an objective tool, allowing for the classification of levels of pa and can be used to estimate pa levels over a specified time. accelerometers have been shown to have good correlations with other measures of pa,7 including the gold standards of energy expenditure such as the doubly labelled water method, and are considered to be a valid estimate of overall pa.8 a limitation of accelerometry is its inability to detect the horizontal component of acceleration, meaning that they are not well suited to measuring movements such as weight lifting and standing v. sitting. nonetheless, in children, the actical accelerometer (used in this study) has been shown to be a valid tool for measuring pa, as shown by pfeiffer et al., where actical activity counts were found to be highly correlated with oxygen consumption (vo2). 9,10 physical activity intervention strategies aimed at improving an increasingly sedentary lifestyle need to be developed for south african children. to do this, we need accurate, reliable measurements of pa, which are feasible for use within a south african context. characteristics of physical activity questionnaires (paqs) that favour their use in studies with large sample sizes11,12 include the low cost of producing and administering the questionnaires, the simplicity of administering the questionnaire, their applicability of use in any setting and their validity in terms of measuring activity.13 on the other hand, paqs also have limitations. accurate assessment is reliant on a person’s ability to correctly recall and record their pa undertaken in the preceding period. in addition, there is large variability in the design of paqs and many have been found to have varying rates of validity. international validation studies performed in children and adolescents that have compared paqs with heart rate monitoring, accelerometry and other pa measures have in general shown good validity of paqs.14-17 however, there is a lack of locally validated questionnaires for the purpose of measuring and reporting pa levels in south african children. while there have been studies conducted within african populations which have used international physical activity recall questionnaires (previous day physical activity recall questionnaire (pdpar))18 and heart rate monitoring as an objective comparative measure,19 few studies have actually objectively validated a paq specifically in south african children. criterion validity and test-retest reliability of a physical activity questionnaire in south african primary school-aged children joanne a mcveigh, shane a norris exercise laboratory, school of physiology, and mrc/wits developmental pathways for health research unit, department of paediatrics, school of clinical medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa joanne a mcveigh, phd mrc/wits developmental pathways for health research unit, department of paediatrics, school of clinical medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa shane a norris, phd corresponding author: j a mcveigh (jo-anne.mcveigh@wits.ac.za). abstract objective. we sought to determine the validity, reliability and ranking ability of an interviewer-administered physical activity questionnaire (paq), measuring physical activity (pa) and inactivity history over a 1-week and 1-year period in south african primary school-aged children. methods.criterion validity of the paq was tested against pa movement counts as measured with an actical accelerometer in 30 children. agreement between the two instruments was measured with a weighted kappa statistic. test-retest reliability of the past week and past year paq was also tested. results. a positive, significant (r=0.53, p=0.004) relationship was found between total time spent being physically active as measured by the actical and paq. a similar relationship was found for time spent doing sedentary (r=0.63, p<0.001) and vigorous activities (r=0.47, p<0.001), but not for activities of a moderate intensity (r=0.001, p=0.88). the ability of the paq to correctly categorise children into activity levels was moderate (κ=0.41, p<0.001). the paq was found to be reliable and reproducible with significant (p<0.001) intraclass correlation coefficients for both the past week and past year administrations. conclusion. the interviewer-administered paq is a useful assessment tool in this population of children, as evidenced by its good correlation with actical measurements. the best application of the questionnaire lies in its ability to qualitatively rank subjects according to activity level. s afr j sm 2012;24(2):43-48. 44 sajsm vol 24 no. 2 2012 in the study of mciza and colleagues, the authors made use of an activitygram as their comparative measure against a paq. the authors reported weak but significantly positive associations between the two measures.20 prista and colleagues have recently used accelerometry to objectively measure physical activity levels in children living in rural mozambique.21 to our knowledge, no other study has used actigraphy to validate a paq in south african children. the paq used in the current study is based on questionnaires which have been previously validated.22-24 while construct validity of the paq has been established in large cohorts of south african children,5,25,26 the main aim of our study was to determine criterion validity of the paq. we examined whether a subjective method of estimating pa and inactivity levels in south african children (using an interviewer-administered paq is valid, reliable and useful for classifying children into categories of physical activity (high to low) by comparing it with an objective measure of pa (actical accelerometry). methods subjects data were obtained from a convenience sample of children recruited from an english-speaking public primary school in johannesburg, south africa. thirty black and white children aged between 9 and 11 years of age participated in a 4-day actical and paq-based study. based on previously published correlation coefficients between paqs and actical data which range between 0.16 and 0.58,27,28 we chose a value of 0.55 (moderate strength) and conducted a sample size calculation on statistica v10. it was estimated that a sample size of 30 children was needed at a power of 90% to ascertain a correlation coefficient of this size. children who were unable to participate in pa were excluded from the study. all children and caregivers gave written informed consent. the study was approved by the human ethics committee of the university of the witwatersrand (ethics no: mo50226). anthropometric measures the height of each child, recorded to the nearest millimetre, was measured using a stadiometer (holtain, uk), and weight, recorded to the nearest 100 gram, was measured using a digital scale (dismed, usa). participants were measured with light clothing and no shoes. physical activity questionnaire the paq used in this study is based on questionnaires which have been previously validated.22-24 however, some questions were modified to make them more appropriate to assess the activities of south african children. our questionnaire assessed pa and inactivity over a period of 7 days and over the past year. the questionnaire was intervieweradministered and children were asked questions regarding estimates of time spent doing physical activities over a 1-week and 1-year period. from the questionnaire, we measured the total time spent in all pa in relation to school, sports (at school and outside of school), commuting to and from school and other leisure time activities (including informal activities, sedentary activities such as television watching, etc.) during the week and on the weekend. a total pa score was calculated from the questionnaire: for all subjects, all activities were rated according to their metabolic intensity based on the method of ainsworth et al.29 the metabolic pa score (metpa) was calculated by multiplying the intensity (multiples of basal metabolic rate (metabolic equivalents)) by the duration of the activity (hrs/wk).29 a sum score metpa was calculated as the sum of all metpa scores for each activity. this metpa score is a gross estimate of activity since we did not subtract the resting energy expenditure (one met) from the gross cost of each activity, as has been used previously by haapanen et al.30 objective measure of physical activity: accelerometry in accordance with international best practice guidelines, 7,31 participants wore actical (mini mitter co., inc., bend, or) accelerometers (hereafter referred to as acticals) affixed on their left hip, slightly above the iliac crest, with an elastic belt for 4 consecutive days. acticals were positioned in this way so that acceleration of the displacement of the hip could be measured and so that the actical would also be sensitive to weight-bearing movements. when positioned on the hip, the device is extremely sensitive to vertical movements of the torso. activity was measured in 1-minute epochs (the recommended epoch length32) over a period of 4 days. in this study, 60 1-second values were summed together to generate one resultant raw activity datum (counts) for each 1-minute epoch.12 the child’s age, weight, height and gender were entered into the acticals memory so that total energy expenditure and pa counts could be estimated using the manufacturer’s equation. the actical is activated when the participant’s information is entered into the unit via a computer interface, and inactivated when the information is downloaded to a computer. a new battery was fitted to each actical before activation. children’s physical activities were divided into three categories based on the number of activity counts generated by the actical: sedentary, moderate and vigorous activity. the cut points described by puyau et al. were used.12 sedentary and light activities had activity counts of less than 1 499, moderate activities had counts of between 1  500 and 6 499 and counts greater than 6 500 were classified as vigorous activities. study design data collection took place over a 2-week period, as depicted in fig. 1. the past week paq was administered on the thursday prior to the actical assessment. this questionnaire examined all activity and inactivity that subjects had undertaken in the past 7 days. the past year paq was administered the next day (friday − day 1 of the actical assessment) and examined all activity and inactivity that subjects had undertaken in the past year. the actical assessment period then took place over 4 days, from and including a friday, saturday, sunday and monday, such that data from both weekday and weekend activity were obtained. the data collected from the acticals were then downloaded onto a computer program (actical v2.000.7 by mini mitter co., inc) and comparisons were made with data obtained from the paqs. children were asked to behave as they normally would for the 4 days of the study and to wear the actical at all times except when bathing or showering. all subjects wore their acticals continuously (except during showering or bathing), as evidenced by the continuous data and counts obtained when the data were downloaded. the accelerometers were brought to the child’s classroom and collected again 4 days later. all procedures were explained to study participants in detail; they were shown how to attach the actical to their hips and the paq was interviewer administered on all occasions. the past week paq was administered for a second time 1 week after the first administration (following thursday) in order sajsm vol 24 no. 2 2012 45 to assess whether the week during which subjects wore the actical was representative of a normal active week for the subjects. the past year paq was administered again the next day (friday) to ascertain whether the data obtained on the past year questionnaire were reproducible. data analysis all data were analysed using spss for windows v12.0 (spss inc, chicago, il, usa). data are presented as means (sd) unless otherwise indicated. intra-class correlation coefficients (iccs) (one-way random effects model) were utilised to evaluate the reproducibility of the estimates of pa obtained from the paq questionnaire. pearson product-moment correlations assessed the magnitude of the relationship between actical measurements and those reported by the subjects on the paq. in addition, the level of agreement between the paq and actical measurement for time spent in sedentary and vigorous activity was estimated using bland-altman plots. weighted kappa statistics were used to assess how accurate the paq is at categorising children into various activity levels. the weighted kappa statistic provides a measure of agreement between two scores which classify observations into one of several groups or categories. kappa values were defined as poor (<0.20), fair (0.21 0.40), moderate (0.41 0.60) and good (0.61 1.00).33,34 an alpha of 0.05 was set a priori to determine the level of statistical significance. results sample characteristics thirty children participated in this study and had a mean ± sd age of 10.17±0.80 years. approximately half of the subjects were black (47%) and 60% of the subjects were female. the mean height of the subjects was 139.2±9.0 cm and weight was 35.2±8.4 kg. average activity counts per day was 54 8241±28 933 counts for the weekdays (friday and monday) and 561 569±46 710 counts for the weekend days. although weekend activity counts were slightly higher, there were no significant differences between the two time frames, although it should be noted that the standard deviation was higher for the weekend activity. eight children (27%) accumulated sufficient physical activity (recommended to be 60 minutes of moderate to vigorous pa per day accumulated in 10-minute bouts35) on the days measured. the counts derived from the actical were further divided into percentages of time spent in sedentary and light, moderate or vigorous activity. subjects spent an average of 54±6.1% of their time each day in sedentary activity as measured by the actical (including sleeping). subjects reported spending 58% of their day in sedentary activity according to the paq. this figure comprised 3.83±0.40 hours per day (16% of day) doing sedentary activities and an average of 10.08±1.03 hours per day (42% of day) sleeping. these figures included after school and weekend time spent television watching, reading, drawing, doing homework, time spent on the computer, and sleeping. in this sample of children, light and sedentary activities were defined to be 2.7 mets or less, moderate activity 2.8 5.9 mets and vigorous activity were activities which generated met scores of 6 and above. children estimated spending 18% of their day in moderate activities (according to the paq), whereas actual time spent in moderate activity as measured by accelerometery was 20% of the day. activity that is classified as vigorous on the actical is approximately equivalent to 6 500+ counts per minute.12 subjects spent an average of 13.3±10.2 minutes of their time each day in vigorous activity as measured by the actical. according to the paq, children spent approximately 19.7±17.3 minutes per day in vigorous activities. average energy expenditure as measured by the actical was 1 256±55 cal/day over the 4-day study period. although children had slightly lower average energy expenditure (1 204±54 cal/day) over the weekday period (friday and monday) compared with the weekend period (1 306±57 cal/day saturday and sunday), there was no significant difference between these two time frames in this sample of children. reliability the intra-class correlations of the estimates of the past year’s and week’s pa (vigorous metpa) and inactivity scores (sedentary activity) as measured twice with a one week interval are presented in table 1. the table shows mean ± sd of the average time spent per week being physically active or sedentary. while inter-week variability in pa is expected, it was important to ensure that the week of actical and paq assessment was not different to an average normal week of activity for the subjects. validity an overall significant, positive correlation was observed for total activity counts and total metpa score obtained over the 4-day fig. 1. schematic representation of the study design. table 1. intraclass correlation coefficients (r) comparing two administrations of the paq one week apart (data are means (ci)) 1st administration 2nd administration icc (ci)* past year vigorous activity (hrs/wk) 6.98 (4.26 - 9.714) 6.83 (4.71   8.93) 0.965 (0.926   0.983) past year moderate activity (hrs/wk) 29.71 (24.04 35.38) 33.32 (30.24 36.39) 0.560 (0.002   0.806) past year sedentary activity (hrs/wk) (excl. sleep) 26.49 (20.92 - 32.06) 25.49 (20.49   30.50) 0.975 (0.947   0.988) past week vigorous activity (hrs/wk) 6.76 (4.05   9.47) 7.62 (5.29   9.97) 0.968 (0.933 0.985) past week moderate activity (hrs/wk) 31.41 (25.74 37.08) 35.80 (28.32 43.28) 0.888 (0.710 0.960) past week sedentary activity (hrs/wk) (excl. sleep) 28.98 (23.84   34.11) 25.97 (20.88   31.07) 0.974 (0.946 0.987) *all correlations are significant at p<0.05. 46 sajsm vol 24 no. 2 2012 period (r=0.53, p=0.004) for all children. to determine whether the relationship held true for activities of varying intensities, correlation coefficients were calculated for time spent in sedentary, moderate and vigorous activity as reported by the subjects on the paq (for the same 4-day period as the actical) and as measured by the actical. a large, positive (r=0.63) and significant (p=0.0003) correlation was observed between the average percentage time spent per day in sedentary activities as reported on the paq and the average percentage of time per day spent in sedentary activity as measured by the actical. both measures included time spent asleep. although the means of the paq and actical were similar for activities of moderate intensity, there was no correlation between the two measures for moderate intensity (r=0.001, p=0.88). for activities of a high intensity, a medium, positive (r=0.47) and significant (p=0.011) relationship between the average time spent per day in vigorous activity (metpa score >6) and the percentage of time in activities classified as vigorous by the actical (activity counts >6 500) was observed. to assess agreement between the two measures, bland-altman comparisons on the time spent in sedentary, moderate and vigorous activity were done. figs 2, 3 and 4 show bias and variability between the two methods for low, medium and high intensity activities. the paq demonstrated good agreement with the actical for activities of low intensity. activities of moderate intensity were not well agreed upon by the two measures although similar means were found. despite the moderate correlation observed for activities of a higher intensity, the paq tends to overestimate time spent in vigorous activity (fig. 4). a weighted kappa statistic (which assumes the categories to be ordered) assessed the strength of the paq at placing children into low, moderate or high physical activity groups. the paq has a moderate ability (κ=0.41) to correctly categorise children into physical activity groups. discussion the primary purpose of this exploratory study was to make use of actical accelerometry to determine the validity and reliability of a paq in healthy south african children. we wanted to determine whether an interviewer-administered paq could be used to accurately assess whether a child can be classified as highly, moderately or not very physically active in relation to their peers. the paq demonstrated acceptable levels of reliability and validity when compared with objective data obtained from the actical accelerometer for activities of a low and high intensity, but not for moderate intensity activities. despite the moderate to strong validity coefficients for sedentary and vigorous activities, the objective data obtained from the actical indicate that the paq is better at approximating time spent in sedentary activity and overestimates time spent in vigorous pa. the strength of the paq used in this study is its ability to qualitatively rank subjects from high to low overall categories of pa. the paq has a moderate ability to correctly rank children into varying levels of objectively determined physical activity levels by the actical. although this study provides valuable information which should be taken into account when wanting to quantify levels of physical activity in children, there were limitations to the study. care needs to be taken when using the paq for further research. this study made use of a fairly homogenous small sample of children from one school. this may limit the applicability of the results to the wider population of south african school children. future studies should examine fig. 2. bland altman plot showing agreement and bias between percentages of time spent in sedentary physical activity as reported on the paq and objectively measured sedentary activity using the actical. fig. 3. bland altman plot showing agreement and bias between percentages of time spent in moderate physical activity as reported on the paq and objectively measured sedentary activity using the actical. fig. 4. bland altman plot showing agreement and bias between percentages of time spent in vigorous physical activity as reported on the paq and objectively measured vigorous activity using the actical. sajsm vol 24 no. 2 2012 47 the use of acticals in a wider age and geographical range of south african children. acticals have limited use in measuring activity that is horizontal in nature. activities such as cycling may not have been accurately recorded by the actical. combining the use of acticals with heart rate monitoring will help to overcome this limitation in future studies. a further limitation concerns the assignment of adult met scores to children’s physical activities. however, since there is a paucity of data on the energy costs of children’s activities, ridley and olds conducted an extensive review and concluded that there is sufficient evidence that adult met scores be used to allot energy costs to children as they are currently the best technique available.36 the same authors went on to develop their own compendium of energy expenditure estimates for youth despite reporting that the error associated with using adult met scores for children is very small.37 we have not used this compendium in this study as we had previously used the paq in other studies and wanted to keep the gross met score allocation consistent. the gold standard for measuring energy expenditure in free living humans is the doubly-labelled water technique, which is expensive and has not been used in humans in south africa. additionally many questionnaires are specifically designed for use in developed countries and their transfer to other cultures in developing countries may not always be appropriate.38 using accelerometery to objectively monitor physical activity is a more costly alternative to questionnaires. acticals are an expensive item to purchase, particularly in south africa, and may therefore be suitable for activity monitoring in a small group of children only. the feasibility of using actigraphy in a large cohort of south african children would largely be fund dependent. there are also other less expensive and validated objective tools, such as the kenz lifecorder and pedometers which have been used in studies outside of south africa.39,40 to date only one study has designed and validated a questionnaire specific to a population in africa,41 although the global physical activity questionnaire (gpaq) has been used and validated within an adult south african population and was found to be a reliable questionnaire to use to estimate time spent in occupational, transport and leisure time respectively (r=0.74; r=0.74; r=0.71).42,43 the international physical activity questionnaire (ipaq) has also been shown to be a valid and reliable measure of physical activity in an adult south african population,44 but has not yet been used in children. one other study has reported weak but significant correlations between a paq and activitygram in south african girls.20 it was necessary to identify a suitable paq to be used in a south african context that has the ability to differentiate very active children from inactive children. a wide range of reliability (r=0.51 0.98) and validity (r=0.20 0.88) coefficients between paqs and accelerometry has been reported in the literature,24,45-48 and although these reported ranges are rather wide, the correlations reported in the present study fall well within them and towards the upper end of both ranges. high reproducibility coefficients established that the week in which the paq was administered was representative of an average week for the children. it is also possible that the children gave average answers irrespective of what their actual activity was for that week. acticals are able to discriminate between sedentary, light, moderate and vigorous activity levels.12 in the present study, actical output was considered as an overall measure of activity and as percentages of time spent within ranges of activity levels (sedentary to vigorous). three findings are of importance. firstly, that the paq and the actical are correlated at a low range of activity; secondly, the relationship between the two instruments holds true for activities performed at a high intensity and thirdly that pa as reported on the paq was consistently reported on the weekly and yearly recall of activity by the subjects. importantly however, the paq is not able to accurately discriminate activities of a moderate intensity, possibly due to the nature of the questions asked. the types of activities associated with a moderate intensity met score may be rather variable in a child’s recall of their activity. nonetheless when looking at a child’s overall placement in terms of activity in categorical terms and in relation to their peers, the paq provided valuable data. it is not surprising that although the two instruments were significantly correlated, the correlation was only moderately strong. it is important to note that our paq could result in misclassification of physical activity levels if too narrow a category is used. however, using three or four broader categories ranging from lowto high-activity levels would help prevent incorrect categorisation of children. the paq used in our study is able to differentiate between different intensities of physical activities and is a useful tool for evaluating pa in english-speaking south african children. however, the relationship between the paq and actical assessments of activity is not along the line of identity suggesting that the paq overestimates at high values of pa and possibly underestimates at low values. nevertheless the relationship allows the paq to be used to confidently divide children into categories of activity (high to low). to our knowledge, this is the first study to make use of actical accelerometry in south african children. results from the first south african national youth risk behaviour survey3 showed that less than one-third of south african children met the recommended requirements of physical activity for children.35 subsequent findings presented in the second south african national youth risk behaviour survey show that this number has indeed worsened, with 41.5% of children surveyed attaining insufficient physical activity levels.4 our findings are in agreement with this, with only 27% of our participants engaging in the recommended amount of moderate to vigorous activity on the days measured. it is thus imperative that we begin to take seriously the culture of inactivity that is fast becoming the norm among our south african children. the construct validity of the paq already established5,25,26 is bolstered by the criterion validity findings presented here. the interviewer-administered paq was found to be a valid and reliable assessment tool in this population of children, as evidenced by its overall good correlation with actical measurements. the paq is an easy-to-administer, cost-effective tool that can be used for discriminating more active children from those who are less active. the paq can be used with ease in large samples of children. while absolute metpa scores can be calculated from the questionnaire, the better application of the questionnaire appears to lie in its ability to qualitatively rank subjects according to activity level. acknowledgement. this work was funded by the medical research council (south africa) and the university of the witwatersrand. references 1. armstrong me, lambert mi, sharwood ka, lambert ev. obesity and overweight in south african primary school children – the health of the nation study. s afr med j 2006;96:439-444. 48 sajsm vol 24 no. 2 2012 2. wareham nj, sluijs em, ekelund u. physical activity and obesity prevention: a review of the current evidence. proc nutr soc 2005;64:229-247. 3. reddy sp, panday s, swart d, et al. umthenthe uhlaba usamila – the south african youth risk behaviour survey 2002. cape town: south african medical research council, 2003. 4. reddy sp, james s, sewpaul r, et al. umthente uhlaba usamila – the second south african youth risk behaviour survey 2008.cape town: south african medical research council, 2010. 5. mcveigh ja, norris sa, cameron n, pettifor jm. associations between physical activity and bone mass in black and white south african children at age 9 yr. j appl physiol 2004;97:1006 -1012. 6. mamabolo rl, kruger hs, lennox a, monyeki ma, pienaar ae, underhay c. habitual physical activity and body composition of black township adolescents residing in the north west province, south africa. public health.2007;10:1047-1056. 7. welk gj. principles of design and analyses for the calibration of accelerometry-based activity monitors. med sci sports exerc 2005;31:s501-511. 8. fogelholm m, hiilloskorpi h, laukkanen r, oja p, van marken lichtenbelt w, westerterp k. assessment of energy expenditure in overweight women. med sci sports exerc 1998;30:1191-1197. 9. pfeiffer k, mciver k, dowda m, almeida m, pate r. validation and calibration of the actical accelerometer in preschool children. med sci sports exerc 2006;38:152-157. 10. puyau mr, adolph al, vohra fa, zakeri i, butte nf. prediction of activity energy expenditure using accelerometers in children. med sci sports exerc 2004;36:1625-1631. 11. lamb kl, brode da. leisure-time physical activity as an estimate of physical fitness: a validation study. j clin epidemiol 1991;44:41-52. 12. puyau mr, adolph al, vohra fa, et al. validation and calibration of physical activity monitors in children. obes res 2002;10:150-157. 13. bjornson k. physical activity monitoring in children and youths. pediatr phys ther 2005;17:37-45. 14. aaron dj, kriska am, dearwater sr, cauley ja, metz kf, laporte re. reproducibility and validity of an epidemiologic questionnaire to assess past year physical activity in adolescents. am j epidemiol 1995;142:191-201. 15. sallis jf, prochaska jj, taylor wc. a review of correlates of physical activity of children and adolescents. epidemiology 2000;32:963-975. 16. treuth ms, sherwood ne, butte nf, et al. validity and reliability of activity measures in african-american girls for gems. med sci sports exerc 2003;3:532-539. 17. argiropoulou ec, michalopoulou m, aggeloussis n, avgerinos a. validity and reliability of physical activity measure in greek high school age children. jssm 2004;3:147-159. 18. engelbrecht c, pienaar a, coetzee b. racial background and possible relationships between physical activity and physical fitness of girls: the thusa bana study. south african journal for research in sport, physical education and recreation 2004;26(1): 41-53. 19. prista a, marques a, maia jar. empirical validation of an instrument to measure habitual physical activity in youth from maputo, mozambique. am j hum biol 2000; 12:437-446. 20. mciza z, goedecke j, lambert ev. validity and reliability of a physical activity / inactivity questionnaire in south african primary schoolgirls. s afr j sports med 2007;19:117-124. 21. prista a, nhantumbo l, silvio s, et al. physical activity assessed by accelerometry in rural african school-age children and adolescents. pediatr exerc sci 2009;21(4):384399. 22. gordon-larsen p, mcmurray rg, popkin bm. adolescent physical activity and inactivity vary by ethnicity: the national longitudinal study of adolescent health. j pediatr 1999;135:301-306. 23. pate rr, heath gw, dowda m. associations between physical activity and other health behaviors in a representative sample of us adolescents. am j public health 1996;86:1577-1581. 24. sallis jf. the development of self-administered physical activity surveys for 4th grade students. res q exerc sport 1993;64:25-31. 25. mcveigh ja, norris sa, wet td. the relationship between socio-economic status and physical activity patterns in south african children. acta paediatr 2004;93:982-989. 26. mcveigh ja, norris sa, pettifor jm. bone mass accretion rates in preand earlypubertal south african black and white children in relation to habitual physical activity and dietary calcium intakes. acta paediatr 2007;96:874-880. 27. mackay lm, schofield gm, schluter pj. validation of self-report measures of physical activity: a case study using the new zealand physical activity questionnaire. res q exerc sport 2007;78:189-196. 28. wolin ky, heil dp, askew s, matthews ce. bennett gg. validation of the international physical activity questionnaire-short among blacks. j phys act health. 2008; 5: 746760. 29. ainsworth be, haskell wl, whitt mc, et al. compendium of physical activities: an update of activity codes and met intensities. med sci sports exerc 2000;32:s498-516. 30. haapanen n, miilunpalo s, vuori i, oja p, pasanen m. characteristics of leisure time physical activity associated with decreased risk of premature all-cause and cardiovascular disease mortality in middle-aged men. am j epidemiol 1996;143:870-880. 31. ward ds, evenson kr, vaughn a, rodgers ab, troiano rp. accelerometer use in physical activity: best practices and research recommendations. med sci sports exerc 2005;37:s582-588. 32. chen ky, bassett dr. the technology of accelerometry-based activity monitors: current and future. med sci sports exerc 2005;37:s490-s500. 33. altman d. practical statistics for medical research. london: chapman & hall; 1991. 34. fleiss jl, cohen j. the equivalence of weighted kappa and the intraclass correlation coefficient as measures of reliability. educ psychol meas 1973;33:613-619. 35. strong w, mauna r, blimke c, et al. evidence based physical activity for school aged youth. pediatrics 2005;146:732-737. 36. ridley k, olds ts. assigning energy costs to activities in children: a review and synthesis. med sci sports exerc 2008;40:1439-1446. 37. ridley k, ainsworth be, ts olds. development of a compendium of energy expenditures for youth. int j behav nutr phys act 2008; 5:45. 38. wareham nj. commentary: measuring physical activity in sub-saharan africa. int j epidemiol 2001;30:1369-1370. 39. mcclain jj, sisson,sb. washington tl, craig cl,tudor-locke c. comparison of kenz lifecorder ex and actigraph accelerometers in 10-yr-old children. med sci sports exerc 2007;39(4):630-638. 40. mcnamara zh, taylor sjc. measuring activity levels of young people: the validity of pedometers br med bull 2010;95(1):121-137. 41. sobngwi e, mbanya cn, unwin c, aspray j. development and validation of a questionnaire for the assessment of physical activity in epidemiological studies in subsaharan africa. int j epidemiol 2001;30:1361-1368. 42. armstrong t, bull f. development of the world health organization global physical activity questionnaire (gpaq). j public health.2006;14:66-70. 43. department of health, medical research council, orcmacro. 2007. south africa demographic and health survey 2003. pretoria: department of health. 44. craig cl, marshall al, sjotrom m, et al. international physical activity questionnaire: 12 country reliability and validity. med sci sports exerc 2003;35:1381-1395. 45. trost s, ward d, mcgraw b, pate r. validity of the previous day physical activity recall (rdpar) in fifth-grade children. pediatr exerc sci 1999;11:341-348. 46. sallis jf, strikmiller pk, harsha dw, et al. validation of interviewerand self administered physical activity checklists for fifth grade students. med sci sports exerc 1996;28:840-851. 47. mcmurray rg, ring kb, treuth ms, et al. comparison of two approaches to structured physical activity surveys for adolescents. med sci sports exerc 2004;36:2135-2143. 48. sirard jr, pate rr. physical activity assessment in children and adolescents. sports med 2001;31:439-454. sajsm cover september 2014.indd issn 1015-5163 a peer reviewed publication of the south african sports medicine association www.sajsm.org.za sports medicine the south african journal of volume 26 | number 3 | october 2014 original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the prevalence and severity of lower back pain in south african university rowers l heyneke, bbio; a green, phd department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa corresponding author: l heyneke (heynekelisa@gmail.com) rowing is a physically demanding sport associated with intensive and long-term training programmes.[1] the primary objective of rowing is to propel the boat using an oar as a fixed lever in flat water.[2] rowing is categorised into sculling, where the rower uses two oars, or sweep, where the rower only uses one oar, either on the left or right side.[2] furthermore, rowing can be undertaken individually or in crews of two, four, or eight, with larger crews often having the addition of a coxswain.[2] the rowing stroke consists of a continuous sequence of repetitive movements which is divided into four phases, namely, the catch/preparation, the drive, the finish/release, and the recovery phases.[2] the spine acts as a cantilever during the rowing stroke and has the responsibility of transferring power from the legs and arms to the oar in the water.[3,4] rowers, similar to others participating in competitive sport, have the risk of acute and chronic musculoskeletal injuries.[1,3] the lower back region or the lumbar spine is the most prevalent site of injury in rowers competing at all levels.[1-3,5,6] there are, however, fewer studies available concerning lbp among the university population. it is important to note that university rowing varies in different countries with regards to training intensity and competitive events [11], therefore studies conducted in other countries may not relate to the south african university rowing population. clark et al.[1] investigated south african university rowers. the study focused on multiple injuries sustained throughout a single rowing season, but with a lack of emphasis on lbp, despite the lower back being reported as the most prevalent injury site. previous research found that the prevalence of lbp varies but is significant in university-level rowers.[1,6,8] furthermore, despite the use of different measurement tools, it has been reported that the severity of lbp in rowers is moderate.[1,6,8] there are multiple self-administered lbp questionnaires available for clinical use which assist in determining its severity [9], however, the athletes disability index (adi) questionnaire is developed specifically for athletes to determine the influence of lbp-related disabilities on sport, exercise, and daily activities.[10,11] based on what was illustrated in previous studies,[1,6,8] the primary aim of this study was to determine the prevalence, severity, and debilitating effects of lbp on university-level rowers in south africa. the secondary aim was to establish any differences regarding lbp prevalence and severity between the sexes. methods participants and study design all male and female rowers aged between 18 to 30 years who were rowing for any of the nine south african university rowing clubs at the time of the study were invited to participate in this study. this quantitative cross-sectional study design included 100 rowers (55 females and 45 males; mean age: 21.3 ± 1.7 years; rowing experience: 3.7 ± 1.9 years). the total estimated student rowing population in 2017 was 280. this was based on the number of participants who attended the 2017 university sports of south africa (ussa) sprints national regatta. this sample size had a margin of error of 7.8% with a 95% confidence level. all participants provided their written consent and ethical approval was granted by the faculty’s research ethics committee (rec-516-2020). data collection data were collected using a close-ended self-administered online questionnaire. permission was obtained from rowing club presidents from the respective universities, and thereafter they were asked to distribute the link for the online background: low back pain (lbp) is a condition prevalent among rowers due to the repetitive and physically demanding nature of rowing. information concerning lbp among university-level rowers is, however, outdated and not widely available. objective: to determine the prevalence, severity and disabilities of lbp among university-level rowers in south africa. methods: an online questionnaire, including the athlete disability index (adi) questionnaire, was distributed to nine south african university rowing clubs. one-hundred participants aged between 18 to 30 years completed the online questionnaires. results: eighty-seven rowers admitted to sustaining lbp either at the time of the study or previously in their university rowing career. these rowers (n=87) completed the athlete disability index (adi) questionnaire which provided a moderate lbp disability score (adi score: 8.1±6.0; adi %: 24.7%±18.1). rowers who had been rowing for a longer duration reported a higher severity of lbp (p=0.001). there was no statistically significant difference for lbp prevalence (p=0.584), or severity (p=0.445) between the sexes. a small significant correlation between age and the adi score (r=0.25, p= 0.021) was reported. the high prevalence and moderate severity highlight the significance of lbp among university rowers. conclusion: this study illustrates the prevalence of lbp with moderate severity among university rowers. future research on lbp risk factors and aetiology is recommended to decrease the negative impact of this condition. keywords: rowing, mechanisms of injury, risk factors, sex differences s afr j sports med 2021;33:1-4. doi: 10.17159/2078-516x/2021/v33i1a9323 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9323 https://orcid.org/0000-0002-0275-0070 https://orcid.org/0000-0002-0457-6950 original research sajsm vol. 33 no. 1 2021 2 questionnaire within their structure. the questionnaire consisted of two separate sections. section one captured demographics including age, sex, rowing experience. this section further defined lbp and determined the prevalence of this condition among the participants. if lbp was reported, participants were required to complete section two. section two was the validated adi questionnaire consisting of twelve questions assessing different themes, namely pain, stretching exercises, strengthening exercises, technical skills, sitting, walking, sleeping, range of motion for the back, fear avoidance behaviour, recreational activities, self-care, and sexual activity.[11] this study omitted the question regarding sexual activity. each question in the adi is scored from 0 to 3, with the sum of the scores ranging from 0 to 36. the adi score was converted to a percentage to determine the disability level or severity of lbp for the athlete. the disability severity percentage was defined as 0-20% – minimal, 20-40% – moderate, 40-60% – severe, 60-80% – very high, and 80-100% – sports retirement.[10] statistical analysis the total score for each participant’s adi questionnaire was calculated with microsoft excel, using the definitions described above. thereafter, a descriptive analysis was performed, and data were presented as mean ± standard deviation (sd). inferential statistics were conducted to identify differences (mann-whitney u test) and relationships (spearman’s correlation) between variables. all statistical tests were performed using the statistical package for the social sciences (spss), version 26.0 (ibm inc, chicago, il, usa) at a significance level of p<0.05. effect sizes were calculated using cohen's d and descriptors defined by hopkins[12] were used: trivial – d: 0–0.2, small – d: 0.2–0.6, moderate – d: 0.6–1.2, large – d: 1.2–2.0, very large – d: 2.0–4.0, nearly perfect – d: 4.0–infinity. results demographics a large number (n=87) of the total sample (n=100) reported either previously or currently suffering from lbp. for the further analysis of severity only these individuals (n=87; average age: 21.4 ± 1.7 years; rowing experience: 4.4 ± 1.7 years) will be discussed. prevalence of the total estimated population, 87 rowers (31%) reported lbp either at the time of the study (n=39) or previously in their university rowing career (n=48). there was no significant difference in the age of each group (table) 1. there was a small difference between these two groups in number of years of rowing (p=0.017) (table 1). on average, those who reported lbp at the time of the study had rowed for a longer time than those who reported lbp previously in their university rowing career. additionally, there were no significant differences between the females (n=48) and males (n=39) who reported lbp for age and number of years of rowing (table 2). severity there were no significant differences in the adi score and disability score (%) between those participants experiencing lbp at the time or the study or previously in their university rowing career (table 1). additionally, there were no significant differences in the adi score and disability score (%) between females and males, indicating similar severity between the sexes (table 2). the disability score (%) for these groups is classified as moderately severe.[10] age was significantly correlated to the adi score (r=0.25, p= 0.021) and the disability score (%) (r=0.25, p=0.019). the length of rowing careers yielded no significant relationships with the adi score (%) (r=0.13, p= 0.249) or disability score (%) (r=0.12, p=0.265). discussion this study aimed to establish the prevalence of lbp in south african university rowers, and to investigate the severity among those who reported lbp and its prevalence between the sexes. the results from the current study reported that lbp was prevalent in the south african university rowing population table 1. a comparison of age, rowing experience, athlete disability index scores and percentages between university rowers (n=87) previously or currently suffering from lower back pain previously experienced lbp (n=48) currently experiencing lbp (n=39) p-value effect size (d) effect size age (years) 21.6 ± 1.8 21.3 ± 1.4 0.442 0.19 trivial rowing experience (years) 4.0 ± 1.8 4.8 ± 1.6 0.017* -0.47 small adi score 8.1 ± 7.3 8.1 ± 3.9 0.175 0.00 trivial disability score (%) 24.7 ± 22.1 24.6 ± 11.7 0.196 0.01 trivial data are expressed as mean ± sd. * indicates p< 0.05. effect size descriptors; trivial (d: < 0.2), small (d: 0.2–0.6). adi, athlete disability index; lbp, lower back pain. table 2. a comparison of age, rowing experience, athlete disability index scores and percentages between female and male university rowers (n=87) reporting historical or current lower back pain female (n=48) male (n=39) p-value effect size (d) effect size age (years) 21.7 ± 1.5 21.1 ± 1.8 0.131 0.36 small rowing experience (years) 4.3 ± 1.6 4.4 ± 1.9 0.472 -0.06 trivial adi score 8.3 ± 6.2 7.8 ± 5.7 0.445 0.08 trivial disability score (%) 25.4 ± 18.9 23.7 ± 17.3 0.669 0.09 trivial data are expressed as mean ± sd. * indicates p< 0.05. effect size descriptors; trivial (d: < 0.2), small (d: 0.2–0.6). adi, athlete disability index; lbp, lower back pain. original research 3 sajsm vol. 33 no. 1 2021 with moderate severity. however, the severity was no different between sexes or those currently and previously reporting lbp. finally, age was correlated to the adi score and disability percentage. the prevalence of lbp in this study (31%) is consistent with previous studies.[1,6,8] the highest prevalence of lbp was reported by those rowing for longer than five years (45%), which is in accordance with teitz et al. [6] who found that the number of years’ rowing is associated with lbp in universitylevel rowers. however, the prevalence of lbp in this study (31%) is slightly higher than the 23% of south african university rowers that reported lbp prevalence in the work of clark et al..[1] the contrast of lbp prevalence between the studies can be attributed to the different study periods. that is, clark et al.[1] only studied injuries within a single rowing season, which may have led to the exclusion of previous lbp reports. the current study investigated reports of lbp throughout the rower’s university rowing career, taking into consideration both current and previous reports, which requires that some participants had to rely on memory recall, which may not be an accurate measure of lbp prevalence. therefore, it remains unclear whether the different study durations impacted the findings. additionally, it is also possible that the difference between the samples of the studies may influence the lbp prevalence findings. the sample presented by clark et al.[1] had an average rowing experience of 5.0 ± 3.5 years compared to the rowers from this study who had 3.7 ± 1.9 years of experience. in contrast to this study and that of teitz et al.,[6], clark et al. [1] found that rowers with more experience had lower reports of lbp. furthermore, the participants from the clark et al. [1] study ranged from university-level rowers to international medal winners, compared to the exclusive university sample used in the current study. other studies have shown that national-level rowers’ experience have higher rates of injury than international-level rowers[13], with rowing experience not influencing lbp prevalence in elite-level rowers.[5] these findings may be attributed to the comprehensive health management of elite athletes through resources and support.[13] amateur athletes may not have the same level of medical care readily available and therefore experience a different approach to injury compared to those athletes of a higher level.[13] this study’s combined sample (n=87) reported an average adi disability of 24.7%±18.1%, which is classified as a moderate disability.[10] these findings corresponded with previous studies which similarly reported a moderate severity of lbp in university rowers.[1,6,8] also, previous studies measured the severity of lbp using different tools, namely, time lost from participation[1,6] and the visual analogue scale (vas) pain scale.[8] measuring severity may be subjective, making it challenging for healthcare professionals to monitor a condition accurately.[9] additionally, evaluating severity through metrics, such as time lost from participation, has been found to be a poor indicator of this severity. specifically, time lost from participation does not account for large volumes of cross-training and absence from infrequent rowing competition.[14] furthermore, the vas pain scale has been used to measure subjective characteristics [15], which may contribute to the element of bias when reporting the severity of a condition such as lbp. the use of different scales and methods to measure lbp severity in university-level rowers has presented a challenge when attempting to draw accurate comparisons between the abovementioned studies. the findings from the current study illustrated no sex-related differences in lbp prevalence and severity. this finding is in accordance with previous studies.[3,4,8] the similarities between the sexes may be attributable to consistencies seen in loads on the spine [3], and similar training variables.[5,6] additionally, minimal kinematic differences are noted between the sexes [16], however males do present a spinal flexion angle which is largely ascribed to lbp aetiology.[3,16] it is suggested that the greater muscle strength and larger muscle fibres seen in males[17] may result in their erector spinae muscles overcoming the kinematic difference. although not seen in this study, it is important to highlight the fact that higher rates of lbp in females can be expected due to these athletes having the consequences of the female triad.[18] the female triad can be further compounded by the non-weight-bearing nature of rowing, as weight-bearing activities are proven to increase bone mineral density.[19] from the results of the current study, it remains unclear to which degree sex-specific factors, such as kinematic differences or the female triad, are attributed to lbp. lbp has been described as a pain, discomfort or ache felt in the low back region that presents for more than one week or interrupts at least one training session or competition.[8] in the current study two groups of pain sufferers were categorised and compared. the groups were established based on current or previous experience of lbp. the results indicated that those currently experiencing lbp were not statistically different in terms of age or pain severity scores found in other studies. however, those rowers currently experiencing lbp had a slightly greater rowing experience. as previously reported [2], lbp is a chronic injury with the primary aetiology of repetitive spinal flexion which occurs during the rowing stroke. as such, those currently experiencing lbp may have had greater exposure to spinal flexion. however, more research investigating lbp aetiology and associated risk factors is required. finally, there was a weak relationship between age and lbp severity in this current study, which may suggest that the development of lbp is a function of age. degenerative spinal changes are more prevalent with age.[20] furthermore, it can be speculated that spinal loading combined with the repetitive spinal flexion seen in the rowing stroke may accelerate the degeneration of the vertebral discs.[20] this early degeneration seen in the spine of rowers, combined with the general agerelated vertebral changes, may explain the demonstration of the weak relationship of lbp severity and aging. lbp risk factors were not investigated in this study, therefore certain findings regarding the prevalence and severity of lbp could not be explored further. another limitation is that the rowing level of each participant was not recorded. additionally, it is important to note that the prevalence reported in this current study may be slightly inflated, due to the questionnaire being designed to determine the severity of original research sajsm vol. 33 no. 1 2021 4 lbp. the study’s design may have resulted in fewer unaffected rowers responding to the questionnaire. however, based on the current responses and estimated sample population, the prevalence (31%) is still high, considering the 7.8% margin of error. furthermore, lbp may be a reoccurring injury among rowers [5], thus presenting these findings is important for healthcare professionals and coaches in order to emphasise the necessary precautions to limit lbp. conclusion in conclusion, this study illustrated the prevalence of lbp in the south african university rowing population with moderate severity. the severity was no different between the sexes or those currently and previously reporting lbp. finally, age was correlated to the adi score and disability percentage. this study highlights the importance for further investigation regarding lbp risk factors and potential causes, which may ultimately assist coaches and medical professionals in decreasing injury prevalence and improving the quality of rowing in the south african university population. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: lh: study design, data collection, data and statistical analysis, manuscript draft and corrections (primary author). ag: study design, data and statistical analysis, manuscript review. references 1. clark j, von finckenstein ma, joubert m, et al. a retrospective study of injuries in rowing during a single season. s afr j sports med 2015;27 (suppl):39-39. 2. thornton js, vinther a, wilson f, et al. rowing injuries: an updated review. sports med 2017;47(4):641-661. [doi: 10.1007/s40279-016-0613-y] [pmid: 27577685] 3. hosea tm, hannafin ja. rowing injuries. sports health 2012;4(3):236-245. [doi: 10.1177/194138112442484] [pmid: 23016093] 4. holt pj, bull am, cashman pm, et al. kinematics of spinal motion during prolonged rowing. int j sports med 2003;24(8):597-602. [doi: 10.1055/s-2003-43273] [pmid: 14598197] 5. newlands c, reid d, parmar p. the prevalence, incidence and severity of low back pain among international-level rowers. br j sports med 2015;49(14):951-956. [doi: 10.1136/bjsports-2014-093889] [pmid: 25645115] 6. teitz cc, o'kane j, lind bk, et al. back pain in intercollegiate rowers. am j sports med 2002;30(5):674-679. [doi: 10.1177/03635465020300050701] [pmid: 12239000] 7. world rowing. world rowing university: world rowing 2020. available at: http://www.worldrowing.com/university/ (accessed 27 october 2020). 8. stutchfield bm, coleman s. the relationships between hamstring flexibility, lumbar flexion, and low back pain in rowers. eur j sport sci 2006;6(4):255-260. [doi: 10.1080/17461390601012678] 9. davidson m, keating ja comparison of five low back disability questionnaires: reliability and responsiveness. phys ther 2002;82(1):8-24. [doi:10.1093/ptj/82.1.8] [pmid: 11784274] 10. noormohammadpour, khezri ah, farahbakhsh f, et al. reliability and validity of athletes disability index questionnaire. clin j sport med 2018;28(2):159-167. [doi: 10.1097/jsm.0000000000000414] [pmid: 28107217] 11. zamani e, kordi r, nourian r, et al. low back pain functional disability in athletes; conceptualization and initial development of a questionnaire. asian j sports med 2014;5(4): e24281 [doi; 10.5812/asjsm.24281] [pmid: 25741417] 12. hopkins wg. a new view of statistics. https://complementarytraining.net/wp-content/uploads/2013/ 10/will-hopkins-a-new-view-of-statistics.pdf (accessed 11 february 2021). 13. finlay c, dobbin n, jones g. the epidemiology of injuries in adult amateur rowers: a cross-sectional study. phys ther sport 2020;41:29-33. [doi: 10.1016/j.ptsp.2019.11.001] [pmid: 31715556] 14. wilson f, gissane c, gormley j, et al. a 12-month prospective cohort study of injury in international rowers. br j sports med 2010;44(3):207-214. [doi: 10.1136/bjsm.2008.048561] [pmid: 18718978] 15. ergin m, girisgin sa, dundar zd, et al. is it possible to objectify the visual pain scale? pak j med sci 2015;31(6):15271532. [doi: 10.12669/pjms.316.8269] [pmid: 26870129] 16. ng l, campbell a, burnett a, et al. gender differences in trunk and pelvic kinematics during prolonged ergometer rowing in adolescents. j appl biomech 2013;29(2):180-187. [doi: 10.1123/jab.29.2.180] [pmid: 22814388] 17. miller ae, macdougall jd, tarnopolsky ma, et al. gender differences in strength and muscle fiber characteristics. eur j appl physiol occup physiol 1993;66(3):254-262. [doi: 10.1007/bf00235103] [pmid: 8477683] 18. daniels jm, pontius g, el-amin s, et al. evaluation of low back pain in athletes. sports health 2011;3(4):336-345. [doi:10.1177/1941738111410861] [pmid: 23016026] 19. thein-nissenbaum j, hammer e. treatment strategies for the female triad in the adolescent athlete: current perspectives. open access j sports med 2017; 8:85-95. [doi: 10.2147/oajsp.s100026] [pmid: 28435337] 20. depalma mj, ketchum jm, saullo tr. multivariable analyses of the relationship between age, gender, and body mass index and the source of chronic low back pain. pain med 2012;13(4):498-506. [doi: 10.1111/j.1526-4637.2012.01339.x] [pmid: 22390231] http://www.worldrowing.com/university/ https://complementarytraining.net/wp-content/uploads/2013/ original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license association of the acute:chronic workload ratio and wellness scores in premier league male hockey players g n veiga,1 msc med; g torres,1 phd; i maposa,2 phd 1 centre for exercise science and sports medicine, school of therapeutic sciences, faculty of health science, university of the witwatersrand, johannesburg, south africa 2 division of epidemiology and biostatistics, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: g torres (georgia.torres@wits.ac.za) the primary objective of sports practitioners is to minimise injuries within a team while simultaneously optimising the players’ training load. team sports players are required to maintain the high level of fitness developed during the pre-season training period throughout the competition phase. in addition, players need to recover from training sessions and manage fatigue levels.[1] this fragile balance of training and recovery poses a challenge for sports practitioners therefore athlete monitoring systems are required to be in place. while monitoring workload through the use of objective measures (such as, gps data of distance covered or heart rate) has been extensively used for the workload management of the athlete, subjective measures (such as, session rating of perceived exertion (srpe) and wellness scores (e.g. muscle soreness, fatigue, sleep quality) have only just begun to gain momentum in the world of sports science. the reliability and validity of such measures have been well-documented.[2] the advantage of utilising subjective measures is that they equate to the athlete’s internal load which is specific to each individual athlete. this link between subjective measures and internal load is of importance in training because it tells us how well the athlete is adapting to the training load imposed.[3] the acute:chronic workload ratio (acwr) has been studied extensively over multiple sports disciplines. studies investigating the viability of acwr as a workload management tool have been conducted with australian rules football players[4], rugby players[5], soccer players[6] and gaelic football players[7], but there is a lack of these types of studies for field hockey players. hockey is unique when compared to other sports as it uses rolling substitutions during gameplay. this could affect the viability of acwr as a workload management tool. furthermore, there is a lack of studies investigating the relationship between evidence-based wellness scores and the acwr. the aim of this study was to investigate acwr, training load, and wellness scores in male university field hockey players during an in-season phase of premier league hockey competition. some studies have highlighted that there may be methodological flaws with the acwr method [8;9]. however, the systematic review by maupin et al.[10] concluded that utilising the acwr for external (e.g. total distance) and internal (e.g. heart rate) loads may be related to injury risk. also, using exponentially weighted moving averages to calculate acwr (as used in this study) may potentially result in a more sensitive measure. the review also stated that the methodological problems with the acwr must be addressed before it can be confidently used to mitigate injury risk. a review by gabbett 11] noted that both coupled and uncoupled acwrs have been associated with increased injury risk; however, the author stated that research comparing coupled and uncoupled acwrs for detecting injury risk has yet to be conducted. gabbett[11] also suggested that rather than focusing solely on the acwr, practitioners should account for known moderators of the workload-injury relationship (e.g. age, training and injury history, chronic workload, physical qualities), and the interpretation of internal and external load variables, together with well-being and physical readiness data. therefore, the acwr may be useful in workload management if analysed in conjunction with other factors that influence the workloadinjury relationship, for example, interpreting a spike in acwr in conjunction with the chronic workload and fitness level.[11] this study did not address the debate of the relationship of the acwr to injury risk but only investigated the relationship between the acwr and wellness scores. background: the relationship between acute:chronic workload ratios (acwr) and the incidence of injury, as well as the relationship between subjective wellness scores and training load, is unclear in hockey players. objectives: this study investigated these relationships to determine if the acwr is a useful workload management tool for field hockey players. in addition, the study investigated the association between specific subjective wellness scores (fatigue, sleep quality, general muscle soreness, mood and stress level) and the acute:chronic workload ratio and training load. the study also assessed the association between individual players’ training loads with the self-reported wellness scores. methods: fourteen male field hockey players from the men’s first team at the university of the witwatersrand participated in the study over ten weeks during a premier league competition phase. a google form was completed within thirty minutes of every training session/match. this form consisted of questions that allowed for the calculation of the acwr. results: no incidence of injury was reported during the tenweek period. acwr scores ranged between 0.67 and 1.87. the acwr was associated with general muscle soreness (p = 0.010) and training load was associated with fatigue (p = 0.002), sleep quality (p = 0.05), general muscle soreness (p = 0.004), and mood (p=0.025). conclusion: there may be some merit in the use of subjective wellness measures as workload management tools in field hockey. further research is required to determine if there is an optimal acwr for this sport. keywords: training workload management, training load, session rating of perceived exertion, fatigue, muscle soreness s afr j sports med 2021;33:1-7. doi: 10.17159/2078-516x/2021/v33i1a9244 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9244 https://orcid.org/0000-0002-3448-4096 https://orcid.org/0000-0002-0197-4718 original research sajsm vol. 33 no. 1 2021 2 the objectives of the study were: (i) to describe the acwrs during a premier league men’s field hockey season; (ii) to determine if there was an association between the acwr and subjective, self-reported wellness scores; (iii) to determine if there was an association between training load and selfreported wellness scores of premier league male hockey players. methods participants fourteen male hockey players ranging between the ages of 1924 years, and playing for the first team at the university of the witwatersrand, johannesburg, south africa, participated in this study (mean ± sd; weight = 72.8 ± 8.0 kg, height = 174.7 ± 6.1 cm). the original sample group consisted of the entire men’s first team (twenty-three players); however, those who did not fill out the self-reported wellness and training questionnaires adequately (80% completion rate) were excluded from the study. the completion rate was calculated as the number of sessions reported by a player, divided by the total number of the team’s sessions over the study period. players with completion rates of > 80% were included in the analysis of this study. prior to data collection, the players were required to provide a signed, written informed consent form to partake in this study. ethical considerations ethical clearance was obtained from the human ethics committee of the university of the witwatersrand (protocol number: m190637). anonymity of participants was achieved through the use of codes for each individual. only the head researcher, supervisor and team coaches had access to the players’ identities. the raw data and results were password protected on a shared worksheet only accessible to the head researcher, supervisor, and team coaches. study design this study was a prospective, longitudinal, cohort, correlational study. the google form included an rpe score for the session (srpe) on a scale from 1 to 10 (10 being the maximal exertion and 1 being rest).[12] the type of physical activity completed during the session (training, match, gym or other) and the duration of the session in minutes were also recorded. athletes completed a wellness questionnaire which included five wellness scores (fatigue, sleep quality, general muscle soreness, stress level and mood) on a likert scale from 1 to 5. each player was asked to fill out the section on the google form (sent via a link to their mobile phone) on training duration and srpe at the end of every training/exercise session/match, as part of the team’s monitoring practices. the wellness scores were completed before bedtime every night. this is in line with other studies in which recovery questionnaires have been completed before bedtime.[13] this study’s choice to complete the wellness questionnaire at bedtime was because the study’s questionnaires investigated the effect of an exercise session on exertion and wellness, over the past 24 hours’ exercise sessions and wellness perceptions. quantifying the acwr srpe-based training load was defined as the srpe multiplied by the session’s duration in minutes (arbitrary units x minutes). the measurement of the acwr has been validated as a workload management tool in previous research.[11,12] acute (one week) and chronic (four weeks) workloads were calculated using the exponentially weighted moving average (ewma) model to describe the acwrs of premier league male hockey players. this model places greater emphasis on the athlete’s most recent workload and a decreased weighting on older workload.[14] the ewma model places greater importance on the more recent workouts as they will have a greater effect on current training adaptations when compared to the older workouts. the acwr was then calculated as the ratio of the acute workload calculation divided by the chronic workload calculation. self-reported wellness the general wellbeing of players was quantified by the use of a previously validated wellness questionnaire.[15] players filled in the questionnaire using a 1 to 5 likert scale to rate their fatigue, sleep quality, general muscle soreness, stress level and mood (1 was rated as poor and 5 was rated as very good). a rating of 5 for fatigue or stress, for example, was equated to the least amount of fatigue or stress. the z-scores of the wellness scores were separately calculated and analysed to determine the degree of week-to-week changes in the athletes’ responses [zscore = (current rating – baseline rating)/standard deviation]. statistical analysis data were categorised into weekly blocks from monday to sunday. the dependant variables (acwr and training load) were log-transformed before statistical analysis was undertaken using the mixed-effects model. the mixed-effects model was used to determine the percentage increase/decrease in relation to a unit increase in the independent variable (i.e. wellness scores). the relationship between log-transformed acwr and wellness scores, as well as the relationship between log-transformed training load and wellness scores, was analysed using linear with mixed-effects regression. for an association between individual players’ training load and selfreported wellness scores, the multiple linear regression model was used. data were analysed using stata (v16) statistical software. a p-value less than 0.05 was considered significant. results acwr and training load the acwr of the players during the in-season showed a mean acwr ranging from 0.67 to 1.89 and a mean (±sd) training load (au) ranging from 489 ± 195 to 814 ± 303 (table 1). acwr and wellness scores a linear mixed-effects regression model estimates describing the relationship between the log (acwr) and each of the five wellness score parameters are shown in table 2. acwr was only associated with general muscle soreness (coefficient: 0.183, ci: -0.324, -0.043, p=0.01). a unit increase in general original research 3 sajsm vol. 33 no. 1 2021 muscle soreness showed an 18% decrease in acwr (table 2). this indicated that muscle soreness improved with the players training less. similarly, a unit increase in fatigue showed a 4.1% decrease in acwr (coefficient: -0.041, ci: 0.182, 0.09, p=0.561), and a unit increase in sleep quality showed a 5.7% decrease in acwr (coefficient: -0.057, ci: 0.185, 0.071, p=0.386). a unit increase in mood (i.e. better mood) showed a 4.9% increase in acwr (coefficient: 0.049, ci: -0.89, 0.186, p=0.49) and a unit increase in the stress level (i.e. less stress) resulted in a 3.9% increase in acwr (coefficient: 0.039, ci: -0.085, 0.162, p=0.54) (table 2). an increase in weeks of training showed a reduction for acwr ranging from 2.4%-2.7% every week, controlling for the different parameters (fatigue, sleep quality, general muscle soreness, stress, and mood) (table 2). fig. 1 provides a visual representation of the weekly training load fluctuations and the athletes’ summative wellness score responses. the wellness zscores ranged from 0.30-0.48 and the acwr had minimal to no influence on a cumulative wellness score, only explaining 12% of the variation (fig. 1). training load and wellness scores this linear mixed-effects regression model estimates describing the relationship between the log (training load) and the five wellness score parameters are shown in table 3. the training load was found to be associated with fatigue, sleep quality, general muscle soreness and mood. the wellness questionnaire was based on a likert scale ranging from 1(feeling as bad as possible) to 5 (feeling as good as possible). the number 5 on the linkert scale represented the positive end of the continuum. table 1. acwr, training load and wellness scores over the 10-week period of the study (n=14) week acwr training load (au)* fatigue sleep quality general muscle soreness stress level mood 1 1.89 ± 0.97 771 ± 333 2.9 ± 0.6 2.9 ± 0.6 2.7 ± 0.6 2.9 ± 1.0 3.6 ± 0.4 2 0.86 ± 0.53 506 ± 294 2.8 ± 0.9 2.9 ± 0.9 3.1 ± 0.7 2.5 ± 0.7 3.4 ± 0.4 3 0.68 ± 0.62 741 ± 314 2.6 ± 0.8 3.4 ± 1.1 2.8 ± 0.9 2.4 ± 0.8 3.2 ± 0.8 4 1.01 ± 0.56 724 ± 372 2.7 ± 0.7 3.0 ± 0.8 2.7 ± 0.4 2.6 ± 0.6 3.3 ± 0.6 5 0.99 ± 0.61 644 ± 240 2.6 ± 0.6 2.8 ± 0.9 2.7 ± 0.8 2.7 ± 0.8 3.3 ± 1.0 6 0.67 ± 0.46 489 ± 195 2.6 ± 0.8 3.3 ± 0.9 2.5 ± 0.7 2.8 ± 0.9 3.2 ± 0.8 7 1.01 ± 0.51 710 ± 378 2.8 ± 0.7 3.2 ± 0.9 3.1 ± 0.6 2.5 ± 0.6 2.9 ± 0.9 8 1.14 ± 0.40 592 ± 376 2.7 ± 0.5 2.9 ± 0.8 2.7 ± 0.5 2.4 ± 0.6 3.0 ± 0.7 9 1.12 ± 0.36 814 ± 303 2.8 ± 0.3 3.0 ± 0.7 2.8 ± 0.6 3.0 ± 0.7 3.7 ± 0.7 10 0.94 ± 0.38 597 ± 191 3.0 ± 0.0 2.9 ± 0.7 2.6 ± 0.4 3.4 ± 0.6 3.4 ± 0.3 data are expressed as mean ± sd. *training load = time of session x srpe. acwr, acute:chronic workload ratio; srpe, session rating of perceived exertion. table 2. linear mixed-model parameter estimated and 95% cis for the relationship between acwr and subjective wellness scores (n=14) fixed effect model 1 model 2 model 3 model 4 model 5 p fatigue -0.041 [-0.182, 0.09] 0.56 sleep quality -0.057 [-0.185,0.071] 0.39 general muscle soreness -0.183 [-0.324,-0.043] 0.01* stress level 0.039 [-0.085, 0.162] 0.54 mood 0.049 [-0.089, 0.186] 0.49 week -0.026 [-0.058,0.005] -0.025 [-0.057, 0.007] -0.027 [-0.058, 0.003] -0.026 [-0.058, 0.005] -0.024 [-0.057, 0.007] data are expressed as coefficient estimates [95% confidence interval]. week indicates the change of acwr from one week to the next. * indicates p<0.05. acwr, acute:chronic workload ratio. table 3. linear mixed-model parameter estimated and 95% cis for the relationship between training load and subjective wellness scores (n=14) fixed effect model 1 model 2 model 3 model 4 model 5 p fatigue -0.215 [-0.349, -0.081] 0.00* sleep quality -0.120 [-0.234, 0.0001] 0.05* general muscle soreness -0.201 [-0.340, -0.063] 0.00* stress level -0.109 [-0.226, 0.008] 0.07 mood -0.151 [-0.283, -0.02] 0.03* week -0.021 [-0.060, 0.0167] -0.020 [-0.056, 0.021] -0.021 [-0.060, 0.020] -0.020 [-0.057, 0.018] -0.025 [-0.06, 0.012] data are expressed as coefficient estimates [95% confidence interval]. week indicates the change of training load from one week to the next. * indicates p<0.05. training load = time of session x srpe. original research sajsm vol. 33 no. 1 2021 4 therefore, a positive change for the five wellness scores would be indicated by a unit increase in the wellness score. a unit increase in fatigue (i.e. less fatigue present) showed a 22% decrease in the training load (coefficient: -0.215, ci: 0.349, -0.081, p=0.002). a unit increase in sleep quality (i.e. better sleep quality) showed a 12% decrease in the training load (coefficient: -0.12, ci: -0.234, 0.0001, p=0.05). a unit increase in general muscle soreness (i.e. less muscle soreness) showed a 20% decrease in the training load (coefficient: -0.201, ci: -0.340, -0.063, p=0.004). a unit increase in mood (i.e. better mood) showed a 15% decrease in the training load (coefficient: -0.151, ci: -0.283, -0.02, p=0.025), and a unit increase in the stress level (i.e. less stress) resulted in a 11% decrease in the training load (coefficient: -0.109, ci: -0.226, 0.008, p=0.068) (table 3). a significant association was found between fatigue (p=0.002), sleep quality (p=0.05), general muscle soreness (p=0.004), mood (p=0.025) and the training load (table 3). however, no association was found between the stress level and the training load. an increase in weeks of training showed a 2.0% 2.5% reduction in the training load every week, controlling for each of the five different wellness scores (table 3). fig. 2 provides a visual representation of the weekly training load and the athletes’ summative wellness score responses. the training load had a minimal to no influence on a summative wellness score, which only explains 0.1% of the variation. fig. 3 depicts the weekly percentage changes in the training load, which ranged from a decrease of 34% to an increase of 46%. the training load’s weekly change had a weak influence on the summative wellness scores, equalling only 34% of these changes (fig. 3). table 4 shows the results for the effects of the wellness scores on the training load for each individual player in the study. generally, the training load was lighter with a “better” (higher) wellness score. player 5 had a significant reduction of 20%, and 14% in his training load, with a decrease in fatigue and improved general muscle soreness, respectively. player 9 had a significant reduction in his table 4. regression coefficients (p-values) for wellness scores on log (training load) adjusting for the duration of activity (training/play/gym) and type of session player fatigue sleep quality general muscle soreness stress level mood 1 -0.03 (0.44) -0.001 (0.98) -0.03 (0.30) 0.05 (0.34) 0.04 (0.45) 2 -0.08 (0.30) -0.04 (0.54) -0.06 (0.36) 0.02 (0.78) 0.07 (0.52) 3 -0.02 (0.79) 0.06 (0.24) -0.03 (0.54) 0.04 (0.47) 0.01 (0.86) 4 -0.23 (0.09) 0.18 (0.45) -0.10 (0.33) -0.05 (0.68) omitted 5 -0.20 (0.01*) -0.04 (0.46) -0.14 (0.02*) 0.02 (0.69) -0.06 (0.33) 6 -0.20 (0.12) -0.06 (0.37) -0.12 (0.15) 0.003 (0.97) -0.19 (0.12) 7 omitted -0.04 (0.84) 0.03 (0.82) -0.16 (0.31) omitted 8 0.05 (0.16) 0.03 (0.41) 0.02 (0.74) 0.02 (0.61) 0.05 (0.16) 9 -0.31 (0.01*) -0.27 (0.01*) -0.13 (0.14) -0.12 (0.18) -0.23 (0.11) 10 -0.15 (0.04*) -0.10 (0.13) -0.04 (0.50) 0.11 (0.31) 0.01 (0.93) 11 -0.32 (0.20) -0.29 (0.23) -0.34 (0.13) -0.12 (0.48) -0.23 (0.13) 12 -0.20 (0.15) -0.09 (0.38) -0.13 (0.30) -0.001 (0.99) 0.20 (0.09) 13 -0.20 (0.04*) -0.29 (0.03*) -0.07 (0.48) 0.16 (0.10) -0.33 (0.01*) 14 -0.07 (0.04*) -0.01 (0.85) -0.021 (0.74) -0.03 (0.38) -0.05 (0.27) data are expressed as regression coefficients (p-values). * indicates p<0.05. omitted indicates no variation on the wellness scores across all measured instances. fig. 1. acwr and wellness z-scores over a training cycle of 10 weeks. acwr, acute:chronic workload ratio. fig. 2. training load and wellness z-scores over a training cycle of 10 weeks. training load (au) = srpe x duration of session (in minutes). original research 5 sajsm vol. 33 no. 1 2021 training load of 31% and 27% for a decrease in fatigue and improved sleep quality scores, respectively. players 10 and 14 had significant reductions in their training loads, with a decrease in fatigue. player 13 manifested significant reductions in the training load, with decreases in fatigue, improvement in sleep quality and better mood scores. the average acwr and wellness z-scores [z-score = (current score – average)/standard deviation] per week of all the players are represented in fig.1. the wellness z-score uses the sum of all the individual wellness scores (i.e. fatigue, sleep quality, general muscle soreness and mood). the average training load and wellness z-scores [z-score = (current score – average)/standard deviation] per week of all the players are represented in fig. 2. the wellness z-score uses the sum of all the individual wellness scores (i.e. fatigue, sleep quality, general muscle soreness and mood). the average percentage (%) changes in training load and wellness z-scores [z-score = (current score – average)/standard deviation] per week of all the players are represented in fig. 3. the wellness z-score uses the sum of all the individual wellness scores (i.e. for fatigue, sleep quality, general muscle soreness and mood). discussion this study investigated the relationship between wellness scores (fatigue, sleep quality, general muscle soreness, stress level and mood) and the acwr, as well as between the wellness scores and training load. the average acwr reported for all the players during the study period ranged from 0.67 to 1.89. there were no injuries reported during the study period. it should also be noted that the risk of injury may have been mitigated due to the injury prevention practice of adjusting the player training loads according to their wellness scores. it could also have been due to an optimal level of physical conditioning that had been developed in the pre-season. the acwr range in this study is larger than that reported in other studies. research has proposed a ‘sweet spot’ range for the acwr of 0.8 to 1.3, within which the relative risk of injury is thought to be minimised.[10] in addition, an acwr above 1.5 is considered the ‘danger zone’ for an increased risk of injury within 7-10 days.[12] a study on professional soccer players found this ‘sweet spot’ to be between 1.00 and 1.25[6], while another study showed it to be between 0.85 and 1.35 in elite rugby players[5]. a separate study investigating gaelic football players found the ‘sweet spot’ to be between 1.35 and 1.5[7]. a possible explanation for the reported greater range of the acwr in this study could be due to the different nature of the sport type (field hockey) investigated, and has a wider range. field hockey also utilises the rule of rolling substitutions during matches. these substitutions make it challenging for players to know the exact number of minutes realistically played during the game when reporting it for the calculation of the acwr. owing to the duration of the session being part of the acwr calculation, the acwr may have been skewed because the player did not report the exact duration of the session. however, this would have only applied to matches. the small sample size of the study could also have contributed to this finding. this study found that the acwr was only associated to one of the five subjective wellness score measurements i.e. general muscle soreness. fatigue, sleep quality, mood and stress levels showed no association with the acwr, yet general muscle soreness was significantly associated with acwr (table 2). this suggests that a player reporting more general muscle soreness (i.e. towards the likert scale number of 1), may be related to the weekly increase in workload as measured by the acwr. the training load was found to be significantly associated with more wellness measurements (i.e. fatigue, sleep quality, general muscle soreness and mood), when compared to the acwr. fatigue, sleep quality, general muscle soreness and mood were associated to the training load, but not to stress levels (table 3). this may indicate that an increase in training load is associated with a player reporting increased fatigue levels, increased muscle soreness and which may affect sleep quality. the individual player responses confirmed this association between the training load and wellness scores by indicating that the training load was lighter with a “better” (higher) wellness score and that the players in our study generally had a homogeneous response to higher wellness scores (table 4). team response analysis found no association with stress levels (table 3). this may be because these factors take effect when a player remains in a high stress or low mood level for a substantial time period. however, this was beyond the scope of this study. the association of some of the wellness scores (fatigue, sleep quality, muscle soreness, mood and stress level) to the acwr and the training load, show that subjective wellness scores could be a consideration when prescribing a training load to a field hockey player, as a means of monitoring this player’s response to the proposed training load. furthermore, the differing associations between the two measures (acwr and fig. 3. weekly percentage changes in training load and wellness z-scores over the 10 week training cycle. training load weekly percentage changes = [(current week training load – previous week training load)/ current week training load] x 100. original research sajsm vol. 33 no. 1 2021 6 the training load) and wellness scores may indicate that the two measures could be measuring different aspects of a player’s workload. other studies have also investigated subjective measures (wellness scores) in the context of training, but these measures were collected before the athletes participated in their training session or match. [15-17] these other studies covered australian football or american college football players. they found that pre-training subjective measures may provide useful information to coaches, such as a player’s level of internal load, as well as potentially indicating a player’s readiness to train. in this study; however, wellness scores (and srpes) were reported after a training session or match (before bedtime). research has also found the srpe-based training load to be a good indicator of internal load in soccer [18]. it was theorised to be a good indicator of a player’s capacity before a training session and a key determinant response to training in american college football.[17] govus et al.[17] found a 1-unit increase in muscle soreness (meaning the player was feeling less sore) which was associated with a 4.4% decrease in the srpe-based training load in american college football. this study found the same unit increase in muscle soreness to be associated with a 28% decrease in the srpe-based training load. a difference in risk factors between the two sports and individual athletes, likely due to varied physiological capacities and physical demands of each sport, could explain the disparity between the two results. ihsan et al.[19] investigated male field hockey players and examined the association between some of the wellness measures (fatigue, muscle soreness, mood state and sleep quality) and match running performance over the course of an international field hockey tournament. the results were normalised for playing time, or post-match rpe, or for both playing time and post-match rpe. ihsan et al.’s study found that changes in a player’s running performance were better associated to changes in wellness scores when running performance was normalised for both playing time as well as post-match rpe. such findings support evidence for the use of wellness measures as pre-match tools to assist in managing internal load of hockey players during a tournament.[19] this study however, used post-training/match data collection and could thus not compare research findings. limitations hockey is a sport which utilises rolling substitutions throughout the match. therefore, this may skew the subjective wellness data of players as they are often unsure of how many minutes they have realistically spent playing. this results in possibly skewed acwr measurements and could make it challenging for the workload to be accurately quantified using self-reported measures. even though the entire team (n = 23 men) were originally included in the study, only fourteen were analysed in the final report. this lack of compliance from players is a constant battle for sports practitioners and limits the accuracy, as well as the generalisability, of the results due to the smaller sample group. collaborating with players so that they understand the value of filling out such questionnaires for their performance enhancement is a suggestion to help improve the compliance of players. a longer period of observation would have been optimal to monitor the players’ workloads, including through their pre-season training. pre-season training is notoriously rigorous and intense as the players are required to reach peak physical conditions in time for the season and then to maintain that peak condition throughout the entire season. the process of the players reaching this level of optimal fitness may add a new level of importance to a study such as this one. an additional limitation of this study was that it did not control for recall biases with the wellness questionnaire that was filled out at bedtime, especially the previous night’s sleep quality. the wellness scores were filled out at some stage during the night of the training/match session to ensure that it is in agreement with the completion of the acwr recording that was done post exercise sessions. this study, by investigating, the relationship between acwr and wellness scores, tried to keep the timing of the reporting of these measures as close as possible. research using the total quality recovery scale has shown that reporting measures post 24 hours is still useful. [13,20] study strengths and future directions the strengths of this study include:  the use of the ewma to calculate the acwr not rolling averages, which is statistically a better method. it is also a more sensitive method for identifying changes in the chronic load and adaptation to training load.[14]  with a small sample of players which were included in this study, using the linear mixed-effects method to assess the association between performance indicators (acwr and training load) and wellness score parameters gives strength to the observed results. the mixed-effects methods incorporated both the fixed and random effects and is suitable for follow-up studies with dependent participant measurements.  the study included training sessions and competition in our analysis, which gave a more complete picture of loading, as opposed to analysing only one aspect of workload (e.g. matches). further studies need to be conducted on the association between the acwr and injury risk in outdoor field hockey across a longer duration (ideally including the pre-season training period), in order to formulate a more accurate estimate of the acwr’s ‘sweet spot’. it is suggested that the subjective measures, such as internal load used in this study, are investigated with a larger sample size and in conjunction with external load measures (such as, distance travelled, running speed etc. measured via gps systems) in field hockey. this could allow for more accurate monitoring of a hockey player’s response to the training load and may be used as a predictor for readiness to train. conclusion this study monitored hockey players over the course of a original research 7 sajsm vol. 33 no. 1 2021 season and considered wellness scores in relation to acwrs and the srpe-based training load. associations between certain wellness scores and the acwr (i.e. with general muscle soreness), and the srpe-based training load (i.e. with fatigue, sleep quality, general muscle soreness and mood) were found. therefore, there may be some merit in the use of subjective, individual wellness measures as workload management tools in field hockey. however, when a summative wellness score is used (wellness z-score), acwr and the training load seem to have minimal to no influence on any wellness scores. training load change per week seems to have a weak influence on all wellness scores. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: gt and cv conceptualised the study design and authored the paper. gv collected the data. gt, gv and im analysed and interpreted the data. all authors contributed to the writing of the paper and all approved the final version of the manuscript. references 1. coutts aj, reaburn p. monitoring changes in rugby league players’ perceived stress and recovery during intensified training. percept mot skills 2008;106(3):904–916. 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[doi: 10.1136/bjsports-2016-097017][pmid: 27852586] 10. maupin d, schram b, canetti e, et al. the relationship between acute: chronic workload ratios and injury risk in sports: a systematic review. open access j sports med 2020;11:51–75. [doi: 10.2147/oajsm.s231405][pmid: 3218285] 11. gabbett tj. debunking the myths about training load, injury and performance: empirical evidence, hot topics and recommendations for practitioners. br j sports med 2020;54 (1):58-66. [doi:10.1136/bjsports-2018-099784][pmid: 30366966] 12. gabbett tj. the training-injury prevention paradox: should athletes be training smarter and harder? br j sports med 2016;50(5):273–280. [doi: 10.1136/bjsports-2015-095788][pmid: 26758673] 13. kenttä g, hassmén p. overtraining and recovery a conceptual model. sports med 1998; 26(1):1-16. [doi: 10.2165/00007256199826010-00001][pmid: 9730537] 14. murray nb, gabbett tj, townshend ad, et al. calculating acute:chronic workload ratios using exponentially weighted moving averages provides a more sensitive indicator of injury likelihood than rolling averages. br j sports med 2017;51(9):749– 754. [doi: 10.1136/bjsports-2016-097152][pmid: 28003238] 15. gastin pb, meyer d, robinson d. perceptions of wellness to monitor adaptive responses to training and competition in elite australian football. j strength cond res 2013;27(9):2518–2526. [doi: 10.1519/jsc.0b013e31827fd600][pmid: 23249820] 16. gallo tf, cormack sj, gabbett tj, et al. pre-training perceived wellness impacts training output in australian football players. j sport sci 2016;34(15):1445–1451. [doi: 10.1080/02640414.2015.1119295][pmid: 26637525] 17. govus ad, coutts a, duffield r, et al. relationship between pretraining subjective wellness measures, player load, and rating-of-perceived-exertion training load in american college football. int j sports physiol perform 2018;13(1):95–101. [doi: 10.1123/ijspp.2016-0714][pmid: 28488913] 18. impellizzeri fm, rampinini e, coutts aj, et al. use of rpe-based training load in soccer. med sci sports exerc 2004;36(6):1042– 1047. [doi: 10.1249/01.mss.0000128199.23901.2f][pmid: 15179175] 19. ihsan m, tan f, sahrom s et al. pre-game perceived wellness highly associates with match running performances during an international field hockey tournament. eur j sport sci 2017;17(5):593–602. [doi: 10.1080/17461391.2017.1301559][pmid: 28398168] 20. osiecki r, rubio tb, coelho rl, et al. the total quality recovery scale as a proxy for determining athletes' recovery state after a professional soccer match. j exerc physiol online 2015;18(3):2732. file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.2466/pms.106.3.904-916 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1136/bjsports-2015-094758 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi.org/10.1080/02640410400021278%5d%5bpmid file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1016/j.jsams.2017.05.010 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1016/j.jsams.2017.05.010 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/.%5bdoi:org/10.1136/bjsports-2015-094817 https://doi.org/10.1016/j.jsams.2016.10.014 file:///c:/users/georgiatorres/library/containers/com.apple.mail/data/library/mail%20downloads/d3f66884-de78-4ffa-a08d-6d99b436f04a/%5bdoi;%2010.1123/ijspp.2016-0090 file:///c:/users/georgiatorres/library/containers/com.apple.mail/data/library/mail%20downloads/d3f66884-de78-4ffa-a08d-6d99b436f04a/%5bdoi;%2010.1123/ijspp.2016-0090 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi%2010.1007/s40279-020-01378-6 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1136/bjsports-2016-097017 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.2147/oajsm.s231405 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.2147/oajsm.s231405 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:10.1136/bjsports-2018-099784 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/.%5bdoi:%2010.1136/bjsports-2015-095788 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1136/bjsports-2016-097152 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1080/02640414.2015.1119295 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1123/ijspp.2016-0714 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1123/ijspp.2016-0714 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1249/01.mss.0000128199.23901.2f file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1080/17461391.2017.1301559 68 sajsm vol 19 no. 3 2007 introduction since the early 1980s it has become increasingly common to have psychologists forming a part of the various countries’ medical teams to the olympic games. australia has been one of the most proactive countries in this regard. since sydney 2000 the australians have aspired to having one psychologist per sporting code. 1 to date, south african multicode teams have on four occasions included a psychologist as part of their travelling teams. two of these were to the allafrica games (c gahwiler in 1999, p nel in 2003), and two to the olympic games (j potgieter in 2000 and c gahwiler in 2004). potgieter reported having 21 formal individual consultations and 3 team consultations at the olympic games in sydney 2000 (unpublished manuscript, 2000). in his report he implies this to be a relatively low number of interventions, and cites the lack of opportunities (preolympics) to establish rapport between psychologist and athletes as the main reason. both gahwiler (unpublished manuscript, 1999) and nel (unpublished manuscript, 2003) found that coaches and athletes they had met with prior to the all-africa games were more likely to use their services during the actual event than athletes they had not consulted with before. this is also consistent with the experiences of non-south african psychologists, e.g. bond in australia 1 and mccann in the usa. 2 an opportunity to meet and develop rapport with travelling team members beforehand is therefore vital to maximising the use of sport psychology services at major events. after the sydney olympics, potgieter used a questionnaire to identify the athletes’ perceptions of how well they had been prepared for the games physically, technically and psychologically. athletes felt least prepared psychologically, with only 66% of them reporting adequate preparation on this level. 3 this is relatively low considering that the event is likely to have been at least one of, if not the most important in these athletes’ careers. potgieter recommended that in future provision be made for more extensive psychological preparation prior to the olympics. 3 one of the main difficulties in implementing this approach has been that in the past, the medical teams (including the psychologist) have usually been appointed at quite a late stage. the bulk of the psychological interventions have therefore only occurred at the actual event. ideally, however, psychological preparation should be an ongoing, practical component of all training programmes, 1 so that the psychologist’s role at the actual event is purely one of crisis management and support. another aspect that has largely been ignored in the south african context, is that of psychological support after the event. potgieter reported that 77% of the south african athletes experienced some feelings of depression after the commentary psychological preparation of the 2004 south african olympic team abstract background. the 2004 athens olympics represented the greatest opportunity for psychological preparation yet afforded a multicode south african team. a coordinating psychologist was appointed a year before the event, with access to financial and other resources. aim. the purposes of this paper are fourfold: (i) to describe a 5-stage model used for the psychological preparation of the 2004 south african olympic team; (ii) to report on the athletes and their management teams’ perceptions of its efficacy; (iii) to describe the perceived positive and negative determinants of these same subjects’ state of mind at the olympics; and (iv) to make recommendations for the existing model’s further improvement. results. the psychological preparation was well received, with almost all athletes and coaches requesting an expansion thereof in the future. recommendations are made for the model’s improvement, particularly for its ongoing implementation throughout the 4-year olympic cycle. correspondence: clinton gahwiler unit 16 sports science institute of south africa boundary road newlands 7700 tel: 021-659-5655 fax: 086-624-7988 e-mail: sportpsych@xsinet.co.za clinton gahwiler (ba hons, ma) sport science institute of south africa, newlands, cape town pg68-73indd.indd 68 10/3/07 3:31:48 pm sajsm vol 19 no. 3 2007 69 sydney olympics. 3 mccann has made similar observations over the course of his significant experience with us olympic teams. 2 in a south african context, both potgieter and gahwiler have in the past recommended that opportunities for post-event support be made available to south african teams (unpublished manuscripts). in light of past experiences, the challenge for the 2004 olympics was to implement a more comprehensive psychological preparation programme, specifically allowing more time for developing rapport between psychologist and team members prior to the games, and to provide opportunities for intervention after the games. this paper has four aims: (i) to provide a synopsis of the model employed for the psychological preparation of the south african olympic team to athens 2004; (ii) to report on the perceptions of athletes, team coaches and managers with regard to the efficacy of this model; (iii) to report on athletes’ and management staffs’ own descriptions of their state of mind at the games, together with their perceptions of the main positive and negative influences in this regard; and (iv) to make recommendations for the ongoing improvement of a model for the psychological preparation of south african multicode teams. methods a 5-phase model for the mental preparation of multicoded teams the structured psychological preparation programme began a year before the 2004 athens olympics, with the appointment of a coordinating psychologist by the national olympic committee of south africa (nocsa). while the ideal would be to have an entire 4-year cycle of duty, electing a psychologist a year in advance certainly presented the opportunity for the most comprehensive psychological preparation programme yet of a multicoded south african team. one of the coordinator’s first tasks was to establish a network of psychologists around the country who were able to (regionally) provide psychological services. in phase 1 of the model, these psychologists were invited to attend a 3-day workshop (see below) in order to ensure consistency of message. phase 1: introduction and individual assessments athletes on nocsa’s ‘operation excellence’ programme were invited to attend the pacific institute’s 3-day ‘investment in excellence’ workshop as an introduction to the psychological preparation. during the workshop each athlete also underwent an individual needs analysis with the coordinating psychologist. the aim of this assessment was to identify psychosocial areas, both within and outside of sport, in which the athlete might benefit from some form of psychosocial intervention. this dual focus is consistent with the common sport psychology principle of facilitating not only the performance of the ‘athlete’, but also the wellbeing of the ‘total person’. 1,4 the author’s own experience suggests that it is impossible to maintain the former (i.e. performance) effectively on a sustainable basis without concurrently managing the latter (i.e. wellbeing). phase 2: intervention based on the individual assessments, where appropriate, athletes were referred to a psychologist close to their home for the actual intervention. this not only ensured ease of access, but also some flexibility in allowing athletes to work with consultants with whom they felt most comfortable. there was ongoing contact between the regional and coordinating psychologists in order to ensure continuity and consistency of message. phase 3: monitoring and feedback the only opportunity the coordinating psychologist had personally to follow-up with team members spread around the country, was at the two pre-olympic training camps, when athletes from all the codes were brought to a communal camp for the purposes of training and logistical preparations. the first was held 3 months before, and the second immediately prior to departure for athens. these camps presented an opportunity for the coordinating psychologist to follow-up on athletes with whom an earlier needs analysis had been conducted, and also to meet with those who had not been seen before. during the second of these camps, the psychologist also addressed the entire south african team, which provided a valuable opportunity for an even broader exposure to the squad, including those members who still had not had any form of contact with the psychologist. phase 4: olympic games the coordinating psychologist attended the games as part of the 11-strong medical team. psychological services were made available 24 hours a day. the psychologist’s self-imposed mandate was to make himself as approachable as possible, without imposing. efforts were also made to be as visible as possible (e.g. at meals, and by organising athletes’ ice-baths), so as to increase the likelihood of being around at what has been described as a ‘teachable moment’ (bond: personal communication), in which one has the opportunity to be particularly effective by being on-hand to say the right thing at the right time. in this report these spontaneous miniconsultations are referred to as ‘unscheduled individual consultations’. aside from these obvious roles, the psychologist generally endeavoured to help out wherever appropriate, and also placed a daily inspirational ‘thought for the day’ in each of the athlete blocks. phase 5: post-olympics for the first time, there was a budget for post-olympic psychological intervention. the aim of this was (where needed) to support the re-integration of positive and negative olympic experiences into the athletes’ future lives and competitions. pg68-73indd.indd 69 10/3/07 3:31:49 pm 70 sajsm vol 19 no. 3 2007 on returning to south africa, the coordinating psychologist immediately wrote a letter to each of the athletes. there were three reasons for this letter: (i) to comment briefly on what they could expect to experience emotionally post-olympics; (ii) to remind them of the post-olympics psychological services available to them; and (iii) to provide them with some feedback of the psychology questionnaires. at the same time, a detailed report was sent to nocsa on the overall psychology programme, with recommendations for the future. feedback questionnaires feedback questionnaires were handed out to south african athletes and their management teams over the last 2 days in athens. these included both ‘descriptive’ questions around their mental state at the olympics, and ‘evaluative’ questions around their perceptions of the efficacy of the current psychological preparation programme and how to improve on it. the distracted nature of the last few days in the olympic village made it difficult to get questionnaires completed and returned. in total, 53 questionnaires were received, 45 of which were from athletes, and a further 8 from their coaches and managers. this represents a response rate of 65% among the athletes, and 24% among their coaches and managers. results the feedback questionnaires provided information on the respondents’ perceptions of the 5-phase model described above, as well as of their own state of mind and what influenced them. a synopsis is given below of the most common responses to selected items of the feedback questionnaire. how well prepared were you psychologically? (scored on a scale 1 7, where 1 = not at all well, 7 = extremely well) athlete responses: 5.3 (range 2 7) coach / manager responses: 5.3 (range 3 7) what affected your state of mind positively? – athlete responses having prepared well generally: 8 (18%) psychological preparation / sport psychologist: 7 (16%) the occasion: 6 (13%) good performances and results: 6 (13%) support and efficiency of coach and manager: 5 (11%) support of team mates: 5 (11%) support of family and friends: 5 (11%) what affected your state of mind positively? – coach / manager responses positive attitudes of team and colleagues: 3 (38%) having prepared well generally: 3 (38%) the occasion: 2 (25%) what affected your state of mind negatively? – athlete responses disappointing performances and results: 9 (20%) coach / manager issues: 5 (11%) fellow team members: 4 (9%) external distractions: 4 (9%) what affected your state of mind negatively? – coach / manager responses lack of support from nocsa staff: 3 (38%) unrealistic expectations by athletes: 2 (25%) what was emotionally the most challenging thing for you? – athlete responses disappointing results: 7 (16%) being away from home for so long: 5 (11%) miscellaneous external distractions: 5 (11%) pressure of expectations: 4 (9%) standard of opposition / competition: 4 (9%) enormity of the occasion: 4 (9%) what was emotionally the most challenging thing for you? – coach / manager responses disappointing results: 2 (38%) how clear are you about what you will be focusing on over the next year or two? (scored on a scale 1 5, where 1 = not at all clear, 5 = very clear) athlete responses: 3.2 (range 1 5) coach / manager responses: 4.7 (range 4 5) how can we further improve psychological services? – athlete responses start the process earlier: 5 (11%) the support was good: 4 (9%) need more of it: 4 (9%) need continuity: 2 (4%) how can we further improve psychological services? – coach / manager responses more continuity preand post-olympics: 6 (75%) psychology consultations from the pre-departure camp in pretoria, through to leaving athens at the end of the games, a total of 87 psychological consultations took place. these may be divided into four types: • formal individual consultations (n=30) in which meetings were scheduled at the athlete’s request • unscheduled individual consultations (n=48) which occurred spontaneously at training venues, over meals, on buses, etc. • formal team sessions (n=5) in which the explicit focus was psychological in nature • attendance at general team meetings (at coaches' request), with occasional psychological contributions (n=4). the most common themes of the combined formal and unscheduled individual athlete consultations were general psychological skills training (n=20), pressure of expectations (n=11), and issues with coach or manager (n=10). pg68-73indd.indd 70 10/3/07 3:31:49 pm sajsm vol 19 no. 3 2007 71 the most common themes of the non-athlete individual consultations were feedback on particular athletes (n=10), issues with sa team management / support staff (n=6), and personal emotional support (n=5). the main theme of the team consultations was team dynamics (n=3). discussion phase 1 – introduction and individual assessments all but one of the athletes (who was writing exams at the time) found the 3-day workshop to be both valuable and enjoyable. from the perspective of the coordinating psychologist phase 1 enabled him to establish rapport with a large proportion of the athletes prior to the actual games (including those with whom he was not working directly). this was a critical determinant of the effective use of psychological services at the games. the importance of the workshop is supported by the relatively high number of psychological consultations proportionate to team size at the athens olympics. having said this, another contributing factor may be that south african athletes and coaches in general are becoming more receptive to the importance of psychological preparation. phase 2 – intervention the model of having one psychologist doing the initial assessment, and thereafter coordinating a national network of other (psychology) service providers, ensured both logistical ease as well as the benefits afforded by continuity. phase 3 – monitoring and feedback phase 3 presented a valuable opportunity to follow up on the initial assessments and to further develop relationships with the athletes. in future, this phase should ideally be extended by including more regular interactions between the coordinating psychologist and the regionally based athletes, management staff and psychologists. this would most easily be achieved by having the coordinating psychologist visit each region regularly (e.g. every 6 months during the 4-year olympic cycle). phase 4 – olympic games in the olympic village, the psychologist was provided with a local cellular phone and all team managers were given the number of this phone. unfortunately, due to space restrictions no central room was allocated for psychological consultations. the biggest challenge this presented was that it made the psychological services less visible. on a functional level, however, this was dealt with by using a tv lounge in a nearby residents’ centre for most formal consultations. other consultations were also (albeit somewhat less privately) held in the lounges of the psychologist's or the athletes' flats. despite the good response to the psychology programme, there were still some athletes who might well have benefited from psychological services prior to, and in athens, but who chose not to use them. judging by the feedback forms, there were many factors which negatively influenced the athletes’ state of mind. the influence from these factors might have been minimised or at least better managed with some (or in some cases further) psychological intervention. it is the author’s opinion that further growing the scope of the preolympic interventions would be a positive development. the high demand of psychological skills training in the individual consultations also suggests that athletes should be exposed to this aspect long before actual events. even though this intervention was the most comprehensive to date, there is still a long way to go before a system is in place which by default includes mental training on an ongoing basis. only a tiny minority (perhaps 2 or 3 athletes) actively resisted any form of psychological support. interestingly, these exceptions tended to be athletes whose coaches were cynical about the role of psychology. this underlines the importance of coaches’ education and involvement in the psychological processes prior to the games. the athens olympics reinforced this author’s opinion that coaches and managers appear to be at particularly high risk of burnout at such events. because their attitudes, moods and behaviours have both a direct and indirect impact on the athletes, it is crucial that they get the appropriate support prior to and also at the multicode event. in future olympic cycles, more attention should be paid to preparing coaches and managers psychologically in the build-up to the games. in athens the psychologist dealt with a surprising number of issues relating to the athlete-coach relationship. in almost all such cases the issues could easily have been prevented if the athlete and coach had had more time to build a trusting relationship. most often these cases occurred where individual athletes had been assigned a coach with whom they had never worked with before. the upshot of this is that coach and athlete end up dealing with (normal) relationship-building crises in the cauldron of the olympic games. in other words, at probably the single most important event of their lives they had to deal with issues which really should have been sorted out years before. in light of the high-pressured context these issues were (not surprisingly) amplified in intensity. it is strongly recommended that this should not be allowed to happen again. assuming that the wellbeing and performance of athletes is the main focus, then on selection of the athlete, appointment of support staff that s/he is comfortable with should become an absolute priority. cases in which this is not possible should be handled in a very sensitive manner by administrators, and also be added to the ‘to do’ list of the psychologists well in advance of the actual games. based on the author’s observations, the pressure of expectations remains one of the most significant limiting factors to performance. besides having access to psychological intervention, the athletes’ exposure to comments about competition outcomes (e.g. expected medal count) should pg68-73indd.indd 71 10/3/07 3:31:49 pm 72 sajsm vol 19 no. 3 2007 also be limited as far as possible. there did seem to be a greater awareness of this compared with the build-up to the sydney games in 2000. however, it remains an area that needs more specific and consistent attention. psychologists have a potentially important role in educating politicians, administrators and other non-competing team members on how to motivate and inspire in a way that does not create unnecessary pressure. in theory the quieter time towards the end of the olympic games is an ideal opportunity to have a debriefing session with the athletes. however, it proved difficult to pin down most athletes at this stage of the event, as many were taking the opportunity to leave the olympic village. in retrospect, the importance of this task was perhaps under-estimated. it is recommended that in future all team members be strongly encouraged to undertake a more structured debriefing process before they leave the olympic village. phase 5 – post-olympics many of the athletes were very unclear about their post olympic futures. this uncertainty and lack of goal-focus was presumably central to the (anecdotally) increasingly recognised phenomenon of post-olympic depression. again, this highlights the importance of post-event debriefing sessions. debriefs are equally important for athletes who plan to continue competing after a major event, as their emotional and cognitive responses to the latter inevitably influence their approach to future events. general if no one else has taken on the task, then the psychologist(s) working with future south african olympic teams should, as one of his/her (pre-olympic) tasks, ensure that the south african living quarters in the games village are both comfortable and personalised. it was apparent in athens (both from south african athletes’ comments and from observing other countries’ living quarters) that little things like sun umbrellas in hot spaces, a comfortable communal lounge in which people from all the codes can interact, can do much for overall team morale. a very strong sentiment among the athletes was that decisions which impacted either directly or indirectly on their performances, were sometimes made in ways which prioritised the decision-maker’s needs above those of the athlete. this is in fact a strong theme running throughout south african sport. as support staff to the athletes, non-athlete team members (including coaching, administrative and medical staff) have a responsibility to try and understand the source of these perceptions without immediately condemning them. in other words, we need to start becoming aware not just of what decisions should be made, but also of how these might best be conveyed to the athletes (in order to have the most beneficial effect on the athlete’s wellbeing and performance). in this regard, psychologists can once again add significant value by playing a greater consulting role with support staff prior to the next olympics. finally, a shortcoming of this paper is that it sought feedback only from athletes and their coaching and management staff. medical (11) and nocsa (8) staff would have provided further useful information. conclusion (and future recommendations) the programme for the psychological preparation of the athens 2004 team was the most comprehensive programme yet employed by a multicoded south african team. in short, this model appeared to work very well, and this author believes that if it is used again, it would provide an excellent foundation on which to improve further the psychological preparation of future south african teams. there was an almost unanimous feeling among athletes, coaches and managers that the existing programme should be expanded and be implemented on an ongoing basis, with the next cycle starting immediately post-olympics. in this regard, the biggest failure of south african sport psychology lies not in the levels and areas of its expertise, but in our collective failure to convince the relevant decisionmakers to support and prioritise ongoing psychological support and development programmes. after all, mental skills are no different to technical skills in needing many years to refine. any short-term intervention (either in response to a crisis or otherwise) is automatically limited in efficacy by its inability to reinforce its teachings over time, and throughout the different levels of that sporting code’s participants. were such a comprehensive programme to be implemented by a sporting body, its vision should be to produce athletes who have the psychological skills to go to any event, in any context (including the high-pressure cauldron of the olympic games), and still be able to compete consistently to the peak of their current potential (as determined by age and experience, availability of resources, etc). in other words, regardless of external circumstances and pressures, the athlete should have the ability to perform at his/her potential. the following is a synopsis of what needs to happen for future south african olympic teams to get as close as possible to this ideal state of preparation: • start the next cycle of psychological preparation immediately post-olympics. • continue the existing model of having a coordinating psychologist working with a network of service providers around the country. the coordinator should be part of the medical team to the olympics. • the aims of the programme should be to psychologically educate and support all potential (athlete and non-athlete) members of the south african team. • the coordinating psychologist should do a comprehensive individual needs analysis with all relevant parties. thereafter individuals should be (where necessary and appropriate) referred to a local service provider for intervention. pg68-73indd.indd 72 10/3/07 3:31:49 pm sajsm vol 19 no. 3 2007 73 • the coordinating psychologist should visit each major centre at least twice a year, with a view to establishing and maintaining rapport with athletes, coaches, regional psychologists and other significant parties. • the coordinating psychologist should maintain ongoing contact between visits, e.g. by sending out educational newsletters. • closer to the next olympics, the coordinating psychologist should organise a series of developmental and organisational workshops with all travelling members of the sa team (including athletes, coaches, managers, nocsa administrative staff and medical team). • the coordinating psychologist should ensure that the accommodation of the sa team in the olympic village is personalised, with a view to maximising comfort, functionality and patriotic spirit. • assuming that this model has been effectively implemented, the role of the psychologist at the games should officially only be one of crisis management and support. • ways of contacting the psychologist in the village should be made as clear and as simple as possible. • the psychologist should have unlimited access to all training venues. • a structure should be put in place to ensure a debriefing process for all. acknowledgements with thanks to: nocsa, ernst & young, mary ann dove, all the psychologists throughout south africa who provided services, and the pacific institute. references 1. bond jw. applied sport psychology: philosophy, reflections and experience. international journal of sport psychology 2002; 33 (1): 19-37. 2. mccann sc. doing sport psychology at the really big show. in: anderson, ed. doing sport psychology. champaign, il: human kinetics, 2000: 20921. 3. potgieter jr. lessons from the olympics: participants’ perceptions of the 2000 games. sa journal for research in sport, physical education and recreation 2001; 23, (1): 51-64. 4. ravizza kh. a philosophical construct: a framework for performance enhancement. international journal of sport psychology 2002; 33(1): 4-18. low level laser therapy quanterra, recently replaced by the rikta device with eu and sa registration, heals by using low energy light, infrared and a fixed magnetic field combined to produce a synergistic beam of healing energy. this energy accelerates the healing process, often quite dramatically, having deep and profound effects within the body. treat conditions such as arthritis, rheumatism, wounds, injuries, acne, sinusitis, burns, bronchitis, angina, colitis, leg ulcers, breast pain, back pain, cystitis, some liver disorders, phlebitis, sports injuries, peripheral vascular disease, hypertension, cellulite and many other conditions. using light to heal distributed in south africa by: maxilife (pty) ltd po box 2783, clareinch, 7740, cape town · tel 021-782-5430 fax 021-782-3294 info@maxilife.co.za www.maxilife.co.za· · pg68-73indd.indd 73 10/3/07 3:31:50 pm original research 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license anterior knee pain and its extrinsic risk factors among runners in under-resourced communities in ekurhuleni, gauteng, south africa s h kunene,1,2 msc; s ramklass,2 phd; n p taukobong,3 phd 1physiotherapy department, university of the witwatersrand, johannesburg, south africa 2school of clinical medicine, university of kwazulunatal, durban, south africa 3institutional planning department, sefako makgatho health sciences university, pretoria, south africa corresponding author: s h kunene (siyabonga.kunene@wits.ac.za) anterior knee pain (akp) is the most problematic symptom among many runners worldwide (15-45%), with females, adolescents and young adults being the most affected.[1,2] runners usually describe akp as pain on the anterior aspect of the knee, beneath or around the edges of the patellar. their pain is usually triggered or made worse by running, squatting, going up and down stairs, cycling and jumping activities. anterior knee pain is a consequence of overuse but can also be experienced after an acute and traumatic injury, such as falling on the knee. any activity that requires consistent compression force on the patellofemoral joint may trigger this kind of pain. the cause of akp is usually multifactorial.[3] anterior knee pain has a negative impact on the quality of life (qol) of many athletes. athletes with akp may experience various problems such as physical limitations, emotional and social difficulties which may have a detrimental effect on their well-being and ability to perform optimally.[4] these experiences may also affect athletes’ participation in their rehabilitation programmes and their return to sport. apart from the physical features, anterior knee pain also has nonphysical features which may influence the recovery of patients. theses non-physical characteristics may include psychosocial-, emotional and mental features. a previous study highlighted the negative impact of akp on the qol of runners from underresourced communities, recommending the need to address the non-physical features when formulating strategies to improve qol among the running population with akp.[5] runners can be predisposed to akp through intrinsic and external factors. intrinsic factors may include a weak vastus medialis oblique, tight gastrocnemius-soleus muscle complex, dysfunction of the hip muscles, foot pronation, generalised joint laxity, limb length discrepancy, patellar malalignment and patellar hypermobility.[6] in particular, tight hamstrings and weakness of the iliotibial band and quadriceps, weak hip control muscles and patellar tilt abnormalities were found to be significant when associated with akp in an under-resourced community in south africa.[7] it is therefore critical that the intrinsic risk factors be considered in the management of akp in order to improve management outcomes.[7] establishing extrinsic risk factors is another important component to be considered when dealing with the management of akp. extrinsic factors which are external to the body may include: the action of running, the level of participation (including training and competition), other types of physical activities and the way they are performed, running surfaces, environmental conditions, and the effect of the equipment encountered during physical activities, e.g. air resistance, gravity and ground reaction forces, and shoes.[2] no previous studies have reported on the association between extrinsic risk factors and akp in runners from under-resourced south african communities. south african healthcare is challenged due to the lack of health resources and scarce professional skills.[8] most healthcare facilities in rural or peri-urban communities do not have rehabilitation healthcare professionals, which results in patients not receiving adequate and holistic rehabilitation services. according to these authors’ experience within physiotherapy clinical settings, injuries associated with akp are experienced by many runners from these under-resourced communities, which often results in the end of their running careers due to lack of rehabilitation services. this in turn leads background: various factors predispose athletes to anterior knee pain (akp), making a holistic assessment with rehabilitation inevitable. due to minimal rehabilitation services in under-resourced communities, runners are less likely to report this injury to medical professionals compared to runners in better resourced communities. objective: the purpose of this study was to report on the prevalence of akp among runners in under-resourced communities and to determine the extrinsic risk factors for this injury. methods: this was a cross-sectional study of 347 runners in total. convenience sampling was used to recruit 183 participants aged between 13 and 55 years with no previous history of knee surgeries, traumatic or degenerative knee conditions. questionnaires were used to collect data on the prevalence of akp and extrinsic risk factors. the spss (version 25) was used to analyse the data. data were presented as frequencies and percentages and the results from chi-square and logistic regression tests were provided. results: forty percent (40%) of participants presented with akp, particularly males (n=106, 58%), young runners (n=94, 51%) and those with 3–5 years of running experience (n=57, 31%). anterior knee pain was associated with age (x2=6.484, p=0.039) and running experience (x2=8.39, p=0.04). the following extrinsic risk factors contributed to akp significantly: training load (p=0.04, odds ratio [or]=1.23), warm-up (p=0.04, or=1.57)’ running shoe condition (p=0.04, or=0.14) and running surface (p=0.05, or=1.2). conclusion: a substantial presence of akp and its extrinsic risk factors were found among all participants. these outcomes suggest that extrinsic risk factors should also be considered when managing akp among runners. keywords: patellofemoral pain, predisposing factors, athletes, poor resourced communities s afr j sports med 2019;31:1-6. doi: 10.17159/2078-516x/2019/v31i1a6090 http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6090 https://orcid.org/0000-0002-4880-2120 https://orcid.org/0000-0003-0451-8942 https://orcid.org/0000-0002-1803-4474 original research sajsm vol. 31 no. 1 2019 2 to poor qol for these runners. this study’s objective was therefore to determine the prevalence of akp and its extrinsic risk factors among runners in under-resourced communities in ekurhuleni, gauteng province, south africa. methods the population for this cross-sectional study included 183 out of 347 long-distance recreational runners from six developing clubs in under-resourced, peri-urban communities in ekurhuleni, gauteng province, south africa. the same methodology was used as in the authors’ previous study.[7] these runners were aged between 13 and 55 years with no history of knee surgery, traumatic or degenerative knee conditions. as in a previous study by these authors a convenience sampling method was used.[7] runners were recruited during their training sessions from six different clubs. a raosoft statistical tool was used to calculate the study’s sample size of 183 runners, taking into consideration a 95% confidence level, 5% margin of error and 50% response distribution (http://www.raosoft.com/samplesize.html). participants were recruited during their training sessions at various training grounds in their areas. self-administered questionnaires were used to collect demographic profiles and the presence of akp and extrinsic risk factors, as described in the previous study.[7] demographic data included gender, age, running experience, and height and weight to calculate their body mass index (bmi). a standardised akp questionnaire by kujala and colleagues was utilised to determine the prevalence of akp. it consisted of 13 short questions about the participant’s knee symptoms and functional limitations associated with akp.[9] the tool has a maximum score of 100 which was used to rate all participants’ akp symptoms. a cut-off score of 83 identified participants with akp as recommended by kujala and colleagues. this standardised akp questionnaire has good test-retest reliability and high validity (icc = 0.92).[9,10] the extrinsic risk factor questionnaire was developed by using the current literature available. it was reviewed by five independent experts for content validity. the reviewers included local senior clinicians and researchers in the field of musculoskeletal injuries. following the review process, a pilot study was conducted among the same population (10% of the sample size) to check its validity. no changes or revisions were made to the questionnaire after the pilot study. this study obtained ethical clearance from the biomedical research ethics committee of the university of kwazulu-natal (bfc377/15). before the data were collected, all participants were given leaflets providing details about the study and they were requested to complete consent forms once they agreed to participate in the study. consent was obtained from parents/guardians of participants younger than 18 years. during the data collection, the first author hand-delivered the questionnaires to the participants during their training sessions and collected them immediately after completion. data were captured using microsoft excel first and later imported into spss for analysis. descriptive statistics included the calculation of frequencies and percentages for single variables. inferential statistics included the calculation of the chi-square to determine the association between variables. logistic regression analysis was done to describe data and explain the relationship between akp and various independent variables (risk factors). the level of significance was set at p ≤ 0.05. results all 183 participants completed the questionnaires. anterior knee pain was present among 40% of the participants. participants who scored ≤83 points were considered to have akp, according to the kujala scoring guide [9]. this study was dominated by males (n = 106, 58%), followed by young people (n = 94, 51%) and thereafter participants with 3-5 years of running experience (n = 57, 31%) (table 1). most participants presented with a normal bmi (n = 110, 60%). anterior knee pain was found to be strongly associated with age (2 = 6.48, p = 0.04) followed by the group of young people table 1. demographics profile of runners (n = 183) demographics categories n % gender male female 106 77 58 42 age (years) 13-17 18-35 36-55 51 94 38 28 51 21 running experience <1 year 1–3 years 3–5 years 6–10 years >10 years 20 49 57 37 20 11 27 31 20 11 bmi <18.5 18.5–24.9 25–29.9 >30 28 110 42 3 15 60 23 2 kunene et al.[7] table 2. anterior knee pain (akp) and demographic profile (n = 183) demographics categories akp n (%) chi-square and p-values gender male female 40 (22%) 33 (18%) 2 = 0.49 p = 0.49 age (years) 13–17 18–35 36–55 18 (10%) 33 (18%) 22 (12%) 2 = 6.48 p = 0.04 running experience <1 year 1–3 years 3–5 years 6–10 years >10 years 7 (4.8%) 22 (12%) 19 (10.4%) 12 (6.6%) 13 (7.1%) 2 = 8.39 p = 0.04 bmi <18.5 18.5–24.9 25–29.9 >30 12 (6.6%) 44 (24%) 14 (7.7%) 3 (1.6%) 2 = 5.38 p = 0.15 kunene et al.[7] original research 3 sajsm vol. 31 no. 1 2019 (n = 33, 18%) and, lastly, running experience (2 = 8.39, p = 0.04). participants with 1-3-years of running experience was the most affected group (n = 22, 12%) (table 2). the results in table 3 pertain to the participants’ level of training, competition and skills. most participants were involved in endurance training (n = 167, 91%) which included mostly running. fewer participants included strength (n = 73, 40%) and flexibility (n = 68, 37%) training in their training sessions. most participants (n = 125, 68%) trained twice or more per week completing 16 – 21 km (n =54, 30%) for more than 60 minutes per training session (n = 82, 45%). fifty-nine (32%) participants participated in competitions a few times a year, followed by those who participated in competitions between 1-2 times per month (n = 51, 28%). distances covered by most participants during competition were 33–42 km (n = 42, 23%), 22–32 km (n = 37, 20%), 16-21 km (n = 35, 19%) and 10-15 km (n = 32, 18%) respectively. only 67 (37%) participants always included a warm-up during and following their training, while most participants regularly included a warm-up (n = 111, 61%) during their training and competition. table 4 includes details of the running equipment used for the participants. many participants used running shoes during training and competition (n = 172, 94%) and a few ran barefoot (n = 11, 6%). stability shoes for neutral pronators (n = 102, 56%) were mostly used, followed by cushioning shoes for supinators (n = 20, 11%). approximately half of the participants reported that their shoes were in good condition (n = 90, 61%). fifty-nine (32%) participants reported that their shoes were slightly damaged and worn-out (fair condition). however, thirty-four participants (19%) reported that their shoes were completely damaged or worn-out. only 33 (18%) participants used orthotic inserts and some used arch inserts (n = 11, 6%). about 33 (18%) reported that they used braces and of these, 17 (9%) used knee braces. soft braces were used among the participants who used braces (n = 24, 13%). participants mostly trained (n = 123, 67%) and competed (n = 149, 81%) on concreate or tar surfaces (table 5). most table 3. level of training, competition and skills (n = 183) factors n (%) training methods strength 73(40) endurance 167(91) stretching 68(37) aerobic 47(26) other 24(13) training frequency never 9(5) 1-3 times/month 33(18) once a week 16(9) ≥2 times/week 125(68) training duration 5-10 min 7(4) 11-20 min 5(3) 21-40 min 43(24) 41–60 min 46(25) >60 min 82(45) running distance covered during training ≤5 km 20(11) 10-15 km 50(27) 16–21 km 54(30) 22–32 km 32(18) 33–42 km 25(14) ≥42 km 2(1) race frequency few times a year 59(32) once a month 38(21) 2–3 times/month 51(28) once a week 20(11) ≥2 a week 15(8) running distance covered during competition ≤5 km 11(6) 10-15 km 32(18) 16–21 km 35(19) 22–32 km 37(20) 33–42 km 42(23) ≥42 km 26(14) warmup during training/competition always 65(36) sometimes 111(61) never 7(4) cool-down during training/competition always 67(37) sometimes 97(53) never 19(10) table 4. running equipment (n = 183) factors n (%) use of running shoes yes 172(94) no 11(6) types of shoes used stability 102(56) motor control 7(4) cushioning 20(11) other 43(24) shoe condition good 90(49) fair 59(32) poor 34(19) use of orthotic inserts yes 33(18) no 150(82) type of orthotic inserts used heel 4(2) arch 11(6) ball of foot 7(4) not sure 11(6) use of braces yes 33(18) no 150(82) body part that use braces knee 17(9) ankle 2(1) both 14(8) type of braces soft 23(13) hard 10(6) table 5. running surface and environment (n = 183) factors n (%) training surface grass 17(9) earth 13(7) concrete/tar 123(67) mixed 30(16) competition surface grass 6(3) earth 5(3) concrete/tar 149(81) mixed 23(13) downhill run mostly 39(21) sometimes 132(72) never 12(7) uphill run mostly 38(21) sometimes 145(79) surface condition (training/ competition) dry 104(57) wet 6(3) mixed 73(40) weather conditions (training/ competition) hot 7(4) warm 41(22) cool 37(20) mixed 98(54) original research sajsm vol. 31 no. 1 2019 4 participants sometimes ran downhill (n = 132, 72%) and uphill (n = 145, 79%) that were mostly dry (n = 104, 57%) while others ran on mixed surfaces (sometimes dry and wet) (n = 73, 40%). nearly all of the participants ran in variegated weather conditions (hot, warm or cool) (n = 98, 54%). the binary logistic regression of extrinsic risk factors to akp among the participants is represented in tables 6a and 6b. the model used showed 35% (nagelkerke r2) of the variance in akp and correctly classified 71% of cases. the following factors contributed significantly to akp: training load (p = 0.04, odds ratio = 1.23); warm-up (p = 0.04, odds ratio = 1.57); running shoe condition (p = 0.04, odds ratio = 0.14); downhill run (p = 0.05, odds ratio = 1.20). other factors did not show any significant contribution to akp among participants. discussion this study described the a higher prevalence of akp among this population of runners compared to the global prevalence which is between 15-45% according to cook el al.[1] young and inexperienced runners were more affected compared to the rest of the population. these results were found to be congruent with other studies.[1,11] the causes of akp have been found to be multifactorial. this section will further discuss the extrinsic risk factors presented in the results section above. various factors were described in this study some of which contributed to akp significantly. training load is one of the factors reported in the literature as a contributor to many sports-related injuries including akp.[12] both underloading and overloading can put a runner at risk of injuries and low performance. in this study, participants who trained two or more times a week were less likely to develop akp compared to those who never trained or trained inadequately. this undertraining or lack of training contributed to many of the participants experiencing akp during running races. according to a study by nielson et al., runners who trained for competition regularly were found to be less likely to have running-related injuries than those who did not train.[12] many injuries are as a result of muscle fatigue which may lead to muscle imbalances. therefore, adequate training lowers muscle fatigue thresholds and allow a runner to perform better. training load and fatigue should always be monitored and modified during training and competition so that injury risks can be lowered. overtraining syndrome is a common problem among athletes in general. it consists of “prolonged fatigue and underperformance, following a period of heavy training or competition, lasting at least two weeks.”[13] as much as overtraining is a good technique to improve performance among athletes, it can lead to bodily harm and underperformance, putting strain on the body and supressing the immune system. this may lead to risks of injuries and illnesses. therefore, it is important for runners to avoid overtraining when preparing for their running races. a runner’s fitness levels, body composition, level of running, injury history and age should be considered when determining training loads. new runners tend to do too much too soon. they should rather consider to increase their training load gradually in order to avoid overuse injuries. this study reported that many participants occasionally included warm-up and cool-down sessions during training and competition. however, warm-up and cool-down factors did not show any significant contribution to akp. warm-up is a lowlevel activity which prepares the body for vigorous activity. in table 6a. logistic regression of extrinsic risk factors (n = 183) factors categories p-values odds ratio 95% c.i. running experience <1 year 1 1–3 years 0.65 0.72 0.17 1.02 3–5 years 0.53 1.59 0.38 1.72 6–10 years 0.74 0.78 0.18 1.93 >10 years 0.11 0.26 0.05 1.37 training load never 1 1-3 times/month 0.10 1.22 0.47 1.59 once a week 0.58 1.37 0.04 1.92 ≥2 times/week 0.04* 1.23 0.66 1.29 competition frequency few times a year 1 once a month 0.64 1.46 0.30 1.04 2–3 times/month 0.45 1.66 0.45 1.12 once a week 0.66 0.58 0.05 1.68 ≥2 a week 0.96 0.93 0.05 1.12 training distance ≤5 km 1 10-15 km 0.51 0.37 0.02 1.42 16–21 km 0.85 1.30 0.080 1.94 22–32 km 0.71 0.57 0.030 1.90 33–42 km 0.94 0.87 0.03 1.14 ≥42 km 0.70 0.66 0.02 1.81 competition distance ≤5 km 1 10-15 km 0.09 0.06 0.00 1.54 16–21 km 0.19 0.02 0.00 1.03 22–32 km 0.27 0.14 0.00 1.79 33–42 km 0.22 0.10 0.00 1.77 ≥42 km 0.21 0.11 0.00 1.36 warm-up always 1 sometimes 0.04* 1.57 0.39 1.97 never 0.53 1.15 0.25 1.71 cool-down always 1 sometimes 0.36 0.48 0.10 1.80 never 0.44 1.70 0.21 1.99 running with shoes yes no 0.90 0.74 0.01 1.07 * indicates significant p value < 0.05 original research 5 sajsm vol. 31 no. 1 2019 order to obtain optimal benefits and reduce injury risks, runners should include specific warm-up exercises in their training programmes.[14] a well-structured and targeted warm-up programme will also reduce the risks of akp in runners. a warm-up programme may include 10-15 minutes of low-level physical activities that mimic the main activity (e.g. walking, slow-paced running etc.) and lower limb dynamic stretching and strengthening exercises. a cool-down is also an important part of training and competition, which allows the body to make a smooth transition from the main activity and a state of rest. a cool-down may include the same kind of low-level physical activities as in the warm-up and lower limb static stretching. running shoes is another critical factor that runners and those training them should consider in order to prevent injuries. this study reported that many participants used running shoes, but more than half participants reported that their shoes were not in good condition. runners with poor running shoes were found to be more likely to get akp. a few runners used shoe inserts (mostly foot arch inserts). it is therefore necessary for runners to get assessed for the appropriate footwear for their gait in order to reduce the risks of akp. footwear should be appropriate for the runner’s foot type. saxena and haddad reported that approximately 76% of their study’s participants benefited greatly from orthotics during their akp rehabilitation.[16] orthotics helps to limit the maximum amount of unwanted foot pronation, reduce the speed of internal tibial rotation by reducing the amount of sudden stresses applied to the under surface of the patella. it would be unnecessary for the vastus medialis oblique (vmo) to work so hard in maintaining proper tracking and positioning of the patella.[15] brukner and khan supports the use of soft foot orthoses or rigid orthoses especially if the subtalar joint and tibial rotations are a problem and intervention is required.[2] use of braces is another factor that is considered to be a contributor to the prevention of akp. according to this study very few runners used braces and those who did, used soft knee braces. as much as knee braces are used by athletes to prevent and treat akp, there is lack of evidence on the benefit of their use. for example, there is little evidence in the literature supporting the use of knee orthoses for pain reduction in athletes presenting with akp.[16] further research is necessary on the use of knee orthoses in treating akp. running surface is another risk factor for injuries. most runners in this study ran on hard concrete/tar surfaces, some of which were downhill. running on a hard surface and going downhill were risks for akp. runners should vary the surfaces they run on to prevent akp injuries. varying exercises is another way to limit the risks of akp. for example, they should consider alternating running with biking, swimming etc. thereby exerting less stress on the knees. conclusion this study reported a substantial number of akp injuries, particularly among males, young runners and those with 3-5 years of running experience. various extrinsic risk factors were identified and the following were found to have contributed significantly to akp among this study’s population: training load, shoe condition, running surface especially running downhill on a hard surface. the outcome of this study suggests a need for the development of prevention, treatment and rehabilitation programmes to address the problems described among runners in poorly resourced communities. to overcome the problem of limited healthcare professional services in many communities in south africa, community-based rehabilitation programmes are highly recommended for runners. therefore a further study is needed to develop akp community-based rehabilitation programmes and a framework for its implementation to assist in the problems facing runners in under-resourced communities. table 6b. logistic regression of extrinsic risk factors (n = 183) factors categories p-values odds ratio 95% c.i. shoe condition good 1 fair 0.56 0.30 0.01 – 1.73 poor 0.04* 0.14 0.00 – 1.99 use of orthotic insert yes 1 no 0.10 0.15 0.02 – 1.42 use of braces yes 1 no 0.11 0.66 0.72 – 1.10 training surface grass 1 earth 0.12 0.05 0.00 – 1.06 concrete/tar 0.77 0.72 0.08 – 1.57 mixed 0.10 0.10 0.01 – 1.54 competition surface grass 1 earth 0.29 1.75 0.10 – 1.77 concrete/tar 0.66 2.43 0.05 – 1.12 mixed 0.35 8.68 0.09 – 1.11 running downhill mostly 1 sometimes 0.05* 1.20 0.97 – 1.96 never 0.15 0.30 0.94 – 1.83 running uphill mostly 1 sometimes 0.54 0.32 0.01 – 1.22 never 0.45 0.46 0.00 – 1.48 running surface dry wet 0.79 0.40 0.02 – 1.35 mixed 0.58 1.52 0.35 – 1.58 weather conditions hot 1 warm 0.40 1.25 0.01 – 1.34 cool 0.45 1.82 0.12 – 1.71 mixed 0.27 0.17 0.01 – 1.87 * indicates significant p value < 0.05 original research sajsm vol. 31 no. 1 2019 6 acknowledgements: the authors would like to thank the university of kwazulu-natal and the university of the witwatersrand for their support and providing the necessary resources for this study. central gauteng athletics are thanked for giving permission to the author to conduct this study. the ekurhuleni runners in particular are thanked for their participation. author contributions: s h kunene: conducted the research project and wrote the manuscript. s ramklass and n p taukobong: assisted and supervised the research project and manuscript. references 1. cook c, hegedus e, hawkins r, et al. diagnostic accuracy and association to disability of clinical test findings associated with patellofemoral pain syndrome. physiother can 2010;62(1):17-24. [doi: 10.3138/physio.62.1.17] 2. brukner p, khan k. brukner & khan’s clinical sports medicine: volume 1 injuries. 5th ed. north ryde, n.s.w. mcgraw-hill education australia, 2017:769-804. 3. lankhorst ne, bierma-zeinstra sm, van middelkoop m. risk factors for patellofemoral pain syndrome: a systematic review. j orthop sports phys ther 2012;42(2):81-94. [doi: 10.2519/jospt.2012.3803] 4. cheung rt, zhang z, ngai sp. different relationships between the level of patellofemoral pain and quality of life in professional and amateur athletes. pm. r 2013;5(7):568-572. [doi: 10.1016/j.pmrj.2012.12.007] 5. kunene sh, ramklass s, taukobong np. the impact of anterior knee pain on the quality of life among runners in under-resourced communities in ekurhuleni, gauteng, south africa. sa j sports med 2018;30(1):1-6. [doi: 10.17159/2078516x/2018/v30i1a4947] 6. halabchi f, mazaheri r, seif-barghi t. patellofemoral pain syndrome and modifiable intrinsic risk factors; how to assess and address? asian j sports med 2013;4(2):85-100. [doi: 10.5812/asjsm.34488] 7. kunene sh, ramklass s, taukobong np. anterior knee pain and its intrinsic risk factors among runners in under-resourced communities in ekurhuleni, gauteng. south african journal of physiotherapy 2018;74(1): a452. [https://doi.org/ 10.4102/sajp.v74i1.452] 8. rasool f, both cj. the nature, extent and effect of skills shortages on skills migration in south africa. sa journal of human resource management 2011;9(1), 287; 1-12. [doi: 10.4102/sajhrm.v9i1.287] 9. kujala um, jaakkola lh, koskinen sk, et al. scoring of patellofemoral disorders. arthroscopy 1993; 9(2):159–163. [pmid: 841073] 10. singer b, singer k. anterior knee pain scale. aust j physiother 2009;55(2):140. [doi.org/10.1016/s0004-9514(09)70048-0] 11. boling m, padua d, marshall s, et al. gender differences in the incidence and prevalence of patellofemoral pain syndrome. scand j med sci sports 2010;20(5):725-730. [doi: 10.1111/j.16000838.2009.00996.x] 12. nielson ro, nohr ea, rasmussen et al. classifying runningrelated injuries based upon etiology, with emphases on volume and pace. int j sports phys ther 2013;8(2):172-179. [pmid: 23593555] 13. budgett r. fatigue and underperformance in athletes: the overtraining syndrome. br j sports med 1998;32(2):107-110. [pmid: 9631215] 14. woods k, bishop p, jones e. warm-up and stretching in the prevention of muscular injury. sports med 2007;37(12):10871099. [doi: 10.2165/00007256-200737120-00006] 15. sexena a, haddad j. the effect of foot orthoses on patellofemoral pain syndrome. j am podiatr med assc 2003;93(4):264-271. [doi: 10.7547/87507315-93-4-264] 16. smith to, drew bt, meek th, et al. knee orthoses for treating patellofemoral pain syndrome. cochrane database syst rev 2015;(12):cd010513. [doi:10.1002/1461858. sajsm 595 (commentarty).indd commentary 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license why are there no platypuses at the olympics?: a teleological case for athletes with disorders of sexual development to compete within their sex category n gamble, 1,2 md, ma; m pruski, 3,4 phd, ma 1 university of alberta, faculty of medicine and dentistry, canada 2 london school of tropical medicine and hygiene, university of london, united kingdom 3 critical care science team, oxford road site, manchester university nhs foundation trust, united kingdom 4 school of healthcare science, faculty of science and engineering, manchester metropolitan university, united kingdom corresponding author: n gamble (ngamble@ualberta.ca) the court of arbitration for sport (cas) in may 2019 upheld the international association of athletics federation’s (iaaf) regulation for testosterone testing of athletes with disorders of sexual development (dsd), a ruling later supported by the findings of the swiss supreme court.[1] as a result, a prominent female athlete, caster semenya, will not be allowed to compete unless her testosterone level is brought within typical female levels. the iaaf acknowledged an element of discrimination but held that this was a ‘necessary, reasonable and proportionate means of achieving the legitimate objective of ensuring fair competition in female athletics in certain events.’ similarly, the swiss supreme court found that semenya’s dsd ‘has a direct impact on performance in sport, which could never be achieved by other women,’ [2] despite the lack of extensive studies and the uncertainty of whether elevated endogenous testosterone levels actually do give an unfair competitive advantage in dsd women.[3] this paper will not engage with the specifics of the cas’s ruling or the iaaf’s policy, but will rather employ a teleological construct to examine the legitimacy of a female athlete with dsd competing as a female. similarly, the paper does not address the question of transgenderism in sports, though there certainly may be instances of athletes with dsd who also identify as transgender. these authors are solely concerned with biological sex and not sociological gender. discussion firstly, a conspicuous premise needs justification: the existence of only two sexes. every human organ is oriented towards specific purposes: a heart for pumping blood, eyes for seeing, and lungs for breathing. the sexual arrangement of the human body also has a biological purpose; it is oriented towards human reproduction. however, unlike other human organ systems (e.g. the cardiovascular system), one individual possesses only half of the necessary structures to complete the reproductive system’s function. a female and a male must come together to complete the sexual apparatus. thus a female is one whose body is oriented towards physiological motherhood, while a male is one whose body is oriented towards physiological fatherhood. these definitions are not simplistically reduced to the difference between male and female gonads, producing large and small gametes, respectively, but also by the males and females distinct arrangements to conceive, protect and nourish children. humans cannot reproduce on their own, nor does reproduction require three (or more) unique participants. a species where an individual could reproduce on its own, e.g. earthworm, can be considered to have one sex. if a species evolved which featured the necessary reproductive components divided into three discrete units (with members of this species each possessing one of these units), that species would have three sexes. human sexual organisation, though, is not reducible to gonads, because if gonads are not present in an individual, one can still discern the purpose of that person’s sexual organisation. analogously, manned rockets are designed for spaceflight. by looking at the rocket’s design one can perceive this purpose – even if the rocket’s engines are removed or were never installed. if a car’s engine was bolted onto the rocket, it would still be a rocket and not a car. the rocket may not be capable of spaceflight without properly functioning engines, but its purpose is still space travel, and it is still a rocket. similarly, a person’s sex is an inherent part of that person, even if the gonads are defective or absent – although gonads remain the fundamental means of achieving the purpose of the reproductive system (like the engines of a rocket). some contend that those with dsd belong to a spectrum between male and female.[4] however, owing to the nature of human reproduction, there is no meaningful category that can exist between male and female. [5] moreover all human foetuses begin on a default path to become female, a path that is only diverted if a sufficient biochemical cascade is both transmitted and received properly within the foetus. dsd occurs when this signal is inappropriately transmitted or received (e.g. an xy foetus with complete androgen insensitivity (cais), will in mid-2019, the controversy regarding south african runner caster semenya’s eligibility to participate in competitions against other female runners culminated in a court of arbitration for sport judgement. semenya possessed high endogenous testosterone levels (arguably a performance advantage), secondary to a disorder of sexual development. in this commentary, aristotelean teleology is used to defend the existence of ‘male’ and ‘female’ as discrete categories. it is argued that once the athlete’s sex is established, they should be allowed to compete in the category of their sex without obligatory medical treatment. indeed, other athletes who possess advantageous genetic or phenotypic traits that fall outside of the human norm have been allowed to compete as humans without restraint. in both cases, if an athlete possesses the essential attributes of being a human or being male or female they should be permitted to compete in those respective categories; athletes’ eligibilities should not be based upon accidental attributes. keywords: disorders of sexual differentiation, gender, sports performance, innate advantage s afr j sports med 2020; 32:1-2. doi: 10.17159/2078-516x/2020/v32i1a7918 mailto:ngamble@ualberta.ca http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7918 http://orcid.org/0000-0002-3198-1994 http://orcid.org/0000-0001-7582-1418 commentary sajsm vol. 32 no. 1 2020 2 develop as a female). in dsd cases, discerning whether a baby is male or female can be difficult, but this merely highlights that pathology – not sex – exists on a spectrum, one defined by severity. dsd is no different from any other embryological pathology.[5] no spectrum of orientations exists for the human heart, despite the numerous possible abnormalities (e.g. tetralogy of fallot). rather, there is a spectrum of pathologies that can alter the heart’s ability to fulfil its purpose. the same is true of dsd. suppose a person was born with a chimeric xx and xy genotype, and sufficient xy cells existed in one of the indifferent gonads for that gonad to become a testis. if that testis secreted sufficient testosterone in the crucial sexual differentiation window to orient the baby towards fatherhood and away from the default reproductive system’s path towards motherhood, that individual will be male – even if the other gonad has the xx genotype and became an ovary. on the other hand, an xy individual with cais is a female whose body is organised around motherhood (notwithstanding that she would have non-functioning testicles in her abdomen). embryologically, her body never received the androgen signal necessary to divert her away from the default female path.[5,6] just like the rocket previously mentioned, without the proper engine, her body still possesses and manifests a certain organisational character towards motherhood, even though her defunct gonads (undescended testes) are a male characteristic. her dsd pathology has obstructed the organisational purpose of her reproductive system – i.e. functioning ovaries and uterus – but that purpose is still present. it is evident that lacking an ovary or uterus does not nullify someone’s femaleness; a cancer patient who has undergone hysterosalpingo-oophorectomy is still a woman. although perhaps counter-intuitive, a person’s sex is not defined by gonads, since the absence or removal of gonads (a not uncommon procedure for females) does not annihilate one’s sex. in teleological terms, ovaries or uteruses are accidental (albeit typical) female properties, and testicles are accidental male properties. similar to the hysterosalpingo-oophorectomy case, a soldier whose testicles were destroyed in a bomb blast is still a male even though he can no longer reproduce. the bomb blast and cancer have hindered the reproductive systems from achieving their purpose but have not made the man ‘un-male’ and the woman ‘un-female’. in human sports, aside from athletic prowess (and the possible addition of a specific weight), there are two fundamental entry requirements for participation: the participant must be human and belong to the sex in which they compete. it is vital that an individual’s eligibility to compete is only judged according to these categories. platypuses do not participate in human swimming competitions becaus e they are a different species, defined by different essential characteristics. however, a human swimmer with webbed feet, somewhat resembling those of a platypus, is no less human and more of a platypus because of them. webbed feet are an accidental feature in humans, having no bearing on a human’s essential attributes, and thus should have no bearing on someone’s eligibility to compete as a human. the same is true of sex. if someone is by essence a female, they should not be required to change their accidental features that are intrinsic to them as individuals to compete. there are only two reasonable alternatives, aside from eliminating sex as a category altogether. the first is to devise some complex algorithm to impose a handicap on performance based on genotypic and phenotypic traits. the second is for sports bodies to require corrective steps for every competitively advantageous trait, from webbed toes to gigantism. yet there are no calls for male athletes with advantageous traits, like michael phelps or gheorghe mureșan, to undergo corrective procedures. additionally, doing nothing is often a genuine medical option. perhaps as a solution, every athlete with atypical attributes could be required to receive corrective treatment if that treatment is deemed safer than or as safe as no treatment, as it may be in semenya’s case (despite the dearth of evidence on the trait’s advantageousness),[3] but not in gheorghe mureșan’s case. however, these solutions seem infinitely complicated and only stand to make the process of determining ‘fair play’ hopelessly controversial. sport is not just about who trains harder, although tenacity and perseverance certainly play an integral role. sporting prowess is also critically influenced by a set of genetic traits. how men and women capitalise on or overcome their inborn traits is a significant dynamic of high-performance athletics. in an era that ostensibly celebrates individual differences and fighting stereotypes, it would seem odd to punish athletes for possessing traits that, while arguably advantageous, have no essential bearing on their eligibility to compete. these authors submit that dsd athletes should be allowed to compete within the sex category to which they belong by essence, with whatever advantages or disadvantages they were born with. conclusion since the caf and iaaf judgments did not question semenya’s sex, the proposal of these authors would ensure that she was treated with the same standard as other athletes with intrinsic advantages. conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. acknowledgements: the authors acknowledge joel gamble for his comments on the manuscript. references 1. york g, waldie p. international sports court upholds testosterone testing for women against caster semenya challenge. the globe and mail, 2019. https://www.theglobeandmail.com/world/articlecaster-semenya-loses-her-challenge-of-new-testosterone-rules-for/ (accessed 23 january 2020) 2. mather v, longman j. ruling leaves caster semenya with few good options. the new york times, 2019. https://www.nytimes.com/2019/07/31/sports/caster-semenya.html (accessed 23 january 2020) 3. huang g, basaria s. do anabolic-androgenic steroids have performance-enhancing effects in female athletes? mol cell endocrinol. 2018;464:56–64. [doi.org/10.1016/j.mce.2017.07 .010] [pmid: 28711608] 4. fausto-sterling a. the five sexes: male and female are not enough. the sciences. 1993;33(2):20–24 [doi.org/10.1002/ j.23261951.1993.tb03081.x] 5. gamble nk, pruski m. teleology and defining sex. new bioeth. 2018;24(2):176–189. [doi.org/10.1080/20502877 .2018.1468601] [pmid: 29733759] 6. barrett ke, barman sm, boitano s, et al. ganong’s review of medical physiology. 23rd ed. new york: mcgraw-hill medical; 2010. chap. 22: reproductive development and function of the female reproductive system. http://dx.doi.org/10.1016/j.mce.2017.07.010 https://www.ncbi.nlm.nih.gov/pubmed/28711608 https://doi.org/10.1002/j.2326-1951.1993.tb03081.x https://doi.org/10.1002/j.2326-1951.1993.tb03081.x file:///c:/users/nathangamble/library/messages/attachments/00/00/99936a49-f76f-4641-833c-80d1442dc6fc/%5bdoi.org/10.1080/20502877.2018.1468601 case report 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license if the shoe fits… should you just wear it? a complete calcaneal stress fracture in a female recreational runner j w burger,1,2 mbchb, dmh; r de villiers,3 mbchb, mmed(rad. d); w derman,1,4 mbchb, phd 1 institute of sport and exercise medicine, division of orthopaedic surgery, department of surgical sciences, faculty of medici ne and health sciences, stellenbosch university, south africa 2 department of psychiatry and mental health, faculty of health scie nces, university of cape town, south africa 3 winelands radiology, institute of orthopaedics and rheumatology, stellenbosch university, south africa 4 ioc research centre, south africa corresponding author: j w burger (drjameswburger@gmail.com) case report history a healthy 43-year-old female recreational runner presented to sports practitioners with severe right heel pain. the reported pain was on the lateral side of her foot, radiating up her calf when she walked. there was also mild foot swelling on activity. she was no longer able to run and had consulted multiple practitioners without receiving a diagnosis. she had been running for the past 12 years with no previous history of severe injury. during the preceding six months, she averaged 50-60 km of running per week and had completed 17 races of between five km and 21 km. she had no recent increases in training volume or intensity. on further inquiry, it was revealed that she had recently changed from a traditional cushioned running shoe to a more minimalist type of running shoe. this new, lighter pair of running shoes had a two mm heel-toe drop, with a stack height of 23 mm at the heel. within three weeks of this conversion, she had completed a 21 km and a five km race. the day after completion of the five km race, she struggled to bear weight on her right foot. there was no noteworthy medical, psychiatric, or surgical history and no current menstrual abnormalities. physical examination on examination, she was physically well, with a body mass index of 19.24. there was unilateral, generalised tenderness over her right calcaneus, with no tenderness noted on calf palpation. no further abnormalities were found on physical examination. the initial differential diagnosis included bone stress injury of the calcaneus, plantar fascial injury, nerve entrapment, and retrocalcaneal bursitis. special investigations x-rays of the foot revealed an oblique fracture of the calcaneus, with surrounding sclerosis (fig. 1a). magnetic resonance imaging (mri) of the hind foot was conducted to exclude any other concurrent pathology. the mri showed a linear stir-hypointense line extending from the posterosuperior to the anteroinferior aspect of the calcaneus, indicating a complete fracture of the right calcaneus, with associated bone marrow oedema (fig. 1b). a dexa scan revealed normal bone mineral density (bmd) and blood tests showed that the patient’s vitamin d levels were within the normal range. further tests of liver function, thyroid function, ferritin, and infective markers were all normal. diagnosis and management a final diagnosis of a complete fracture of the right calcaneus was made. initial management consisted of non-weight bearing in a controlled ankle motion walking boot with crutches, followed by partial weight bearing in a controlled ankle motion walking boot. a graded return-to-sport programme was followed successfully without incident. this programme included swimming to maintain cardiorespiratory fitness, with a stepwise addition of more weight-bearing exercise through the use of an elliptical, walking, and ultimately, running. she was running again after four months and completed her first 10 km race six months following her injury. currently, running is her main form of exercise, and she covers 40-50 km per week. she has had no further bone stress injuries after returning to traditional cushioned shoes. discussion bone stress injuries are common sport-related injuries in athletes and can represent up to 20% of injuries that present to shoe choice by runners may follow trends related to purported generalised benefits rather than following an individual riskbenefit analysis. the benefits and risks related to minimalist footwear for running has been a much debated topic. the authors report a case of a complete calcaneal stress fracture in an otherwise healthy female recreational runner in the first three weeks following her conversion from a traditional cushioned running shoe to a minimalist type of running shoe. clinicians should be aware of the potential added bone stress with reduced cushioning and the potential risks in transitioning to new footwear. keywords: bone stress, injury, running, footwear, minimalist s afr j sports med 2020; 32:1-3. doi: 10.17159/2078-516x/2020/v32i1a8522 https://orcid.org/0000-0003-2388-5019 https://orcid.org/0000-0001-6114-126x https://orcid.org/0000-0002-8879-177x http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8522 case report sajsm vol. 32 no. 1 2020 2 sports physicians.[1] these injuries may occur in normal bone in response to excessive loads or repeated load cycles, or in weakened bone as a result of normal loads. with repeated stress and inadequate recovery, local osteoclastic activity exceeds the osteoblastic capacity and subsequent loading causes microfractures in the trabecular bone, before eventually causing breaks in the cortical bone if the stress pattern continues.[1] many bones in the lower limb sustain these injuries and their individual incidence varies according to sport, although the tibia, fibula, and metatarsals are some of the most frequent sites.[1] although bone stress injuries of the calcaneus are welldescribed as a differential of heel pain, this case is unusual as the bone stress injury of the patient’s calcaneus developed into a significant complete facture over a short period of time, and in the absence of any abnormality of bone density or other medical concerns. there are many recognised extrinsic and intrinsic risk factors for a bone stress injury that have been identified, but the exact role that footwear plays in the pathogenesis of these injuries has been contentious.[2] typically, a bone stress injury follows sudden or rapid increases of load stress cycles during weight-bearing training.[1] other recognised risk factors for a bone stress injury include female gender, menstrual dysfunction, low bone mineral density, low caloric intake and, most importantly, combinations of these factors.[1] since the 2000s, there has been an increase in the popularity of minimalist running shoes, owing to the initial hypothesis that they may reduce injury or improve running economy.[3] however, neither traditional cushioned shoes nor minimalist shoes have been shown to reduce overall injury rates.[2] minimalist shoes may merely change the type of injuries that are seen, rather than the overall frequency of injuries. minimalist running shoes aim to mimic the biomechanics of barefoot running, strengthen musculature, and reduce stress on the lower limbs, while still providing protection from the surfaces on which one runs.[3] there is some evidence that minimalist shoes may improve running economy, but these changes come with increased loading of the ankle, achilles tendon, and the metatarsophalangeal joint.[2] it is not yet clear whether this change in running economy is due to nonrearfoot striking or simply the reduced shoe weight.[2,4] the vast majority of runners (between 75-95%) are rear-foot strikers and almost half of recreational runners may continue to rear-foot strike in minimalist shoes.[5] with reduced cushioning at the heel in minimalist shoes, this could potentially place these runners at an increased risk for stress fractures. however, there is currently insufficient evidence to recommend changing a healthy runner’s strike pattern. in fact, it could be potentially harmful to change loading patterns, with limited benefits.[4] it is often in the transition periods between changing shoes or foot-strike where there is the potential for injury.[2,6] conclusion transitioning between shoe types or running form could potentially cause harm to the runner through injury. after 12 years of running without significant injury, this recreational runner developed a bone stress injury in the three weeks following a change in her shoe type, which progressed to a complete fracture of the right calcaneus. clinicians should exercise caution when dealing with uninjured, healthy athletes who wish to change their shoes and should be able to counsel them on the risks and benefits of transitioning. patient consent: the authors would like to thank the athlete for her consent to use her clinical data in this case study. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: jwb; design, writing of manuscript, interpretation of data, critical revision of manuscript content, approval of version to be published. rdv; interpretation of data, critical revision of radiological content, approval of version to be published. wd; conception, design, interpretation of data, critical revision of manuscript content, approval of version to be published. fig. 1a. lateral x-ray showing oblique stress fracture of the calcaneus with surrounding sclerosis. fig. 1b. sagittal stir ankle showing hypointense fracture line with surrounding bone marrow oedema. case report 3 sajsm vol. 32 no. 1 2020 references 1. fredericson m, jennings f, beaulieu c, et al. stress fractures in athletes. top magn reson imaging 2006;17(5):309–325.[ doi:10.1097/rmr.0b013e3180421c8c][pmid: 17414993] 2. sun x, lam w, zhang x, et al. systematic review of the role of footwear constructions in running biomechanics : implications for running-related injury and performance. j sport sci med 2020; 19(1):20–37. available at: https://www.ncbi.nlm.nih.gov/pmc/articles/pmc7039038/[p mid: 32132824] 3. perkins kp, hanney wj, rothschild ce. the risks and benefits of running barefoot or in minimalist shoes: a systematic approach. sports health 2014;6(6):475–480. [doi:10.1177/1941738114546846][pmid: 25364479] 4. anderson lm, bonanno dr, hart hf, et al. what are the benefits and risks associated with changing foot strike pattern during running? a systematic review and meta-analysis of injury, running economy, and biomechanics.sports med 2020;50(5):885-917. [doi:10.1007/s40279-019-01238-y][pmid: 31823338] 5. larson p. comparison of foot strike patterns of barefoot and minimally shod runners in a recreational road race. j sport health sci 2014;3(2):137–142. [doi:10.1016/j.jshs.2014.03.003] 6. ryan m, elashi m, newsham-west r, et al. examining injury risk and pain perception in runners using minimalist footwear. br j sports med 2014;48(16):1257–1262. [doi:10.1136/bjsports-2012-092061]{pmid: 24357642] original research sajsm vol. 24 no. 4 2012 127 commentary the groin, an anatomical region where diagnosis and symptoms are often confusing, may also represent a ‘bermuda triangle’ for clinicians to disappear in vortices of suppositions and assumptions. the wellknown fifa sports physiotherapist, dr mario bizzini, called groin pain ‘the bermuda triangle of sports medicine?’ ‒ with good reason.1 why is there so little international consensus on diagnosis, pathophysiology, investigation and management? is this because the diagnosis is multifactorial and there are 82 differential diagnoses relating to the groin, as well as another 41 related to the hip? it is not simple. in elite sports it is often very difficult for a doctor to diagnose accurately and thus be able to send the player to the relevant specialist who deals only with a specific area. there are anecdotal examples, such as that of a top professional sportsman who has had four different specialist opinions and four different surgical procedures. one needs sound clinical judgement for the overall picture. one of the key points is to understand the entire anatomy and the likely generator of pain. the two joints in the pelvis should be emphasised – the hip joint and the pubic symphysis ‒ which are at the centre of many movements. the term osteitis pubis (op) to describe groin pathology2 is now used with caution, because no clinical parameter develops in isolation.3 also, an mri scan showing bone marrow oedema in the symphysis pubis does not always correlate with the clinical symptoms. this is often the case in professional footballers where asymptomatic op is fairly common. studies suggest that the radiological consequence of bone marrow oedema in sport represents load ‒ nothing more ‒ and is part of mechanotransduction adaptation of the osteocytes in the bone in response to increased activity.4 radiology needs to be balanced with the physical examination to determine the true nature of the findings and at no stage should be used as a definitive diagnosis. garvey et al. state that it is most important to deal firstly with the pubic joint and its relevant attachments, although one should always bear in mind the associated structures around the pelvis and the entire kinetic chain.5 brukner and kahn emphasise that the increased load on the pelvis should be identified and reduced as a matter of course.6 it would be most useful if studies could show whether the increased signal/presence of bone marrow oedema is a precursor to the development of groin pain. an important question is whether clinicians really understand the importance of the adductor muscles. adductor muscle injuries are present in 13 70% of groin injuries. adductor pain without strength loss is commonly associated with a hip condition. adductor longus dysfunction may result in instability and anterior subluxation of the symphysis. both entities are mechanically related and op and adductor dysfunction frequently coexist. adductor strength may be an important objective outcome for prevention and rehabilitation and to assess return-to-play readiness, as well as for identifying and reducing the sources of increased load on the pelvis. it is also important to consider the other anatomical structures around the groin, including the ilio-psoas, ligamentum teres, greater trochanter area, gluteus medius and rectus abdominus.7 these anatomical structures may have to adapt to extraordinary biomechanics around the groin area and need to be addressed in prehabilitation/rehabilitation management. further, the pelvic floor may need to be considered if all other signs of groin pain have been cleared. experienced clinical judgement and clinical reasoning remain a critical element in the diagnostic pathway. there is no ‘one-stop shop’ to diagnose all. although it is generally believed that conservative management should be undertaken before surgery is considered, the time line differs with different specialists. there are some fundamental principles, including maximising the range of motion in the hips, regaining effective muscle strength without stressing the pubic symphysis, facilitating abdominals/ adductors as pubic symphysis stabilisers, and ensuring that a global strengthening programme is undertaken. it is most important to establish a benchmark and progress with objective functional and clinical markers that are monitored on an on-going basis. postoperative rehabilitation programmes varied from 3 to 12 weeks. in surgical management there are most differences of opinion and one should be sceptical of one-size-fits-all operations. there are a number of varied surgical opinions ranging from the time span for conservative treatment prior to surgery to the actual surgical procedure, and to the time line for return to play. with hernias, there is controversy regarding the prevalence of a true hernia. there is currently no consensus as to the ideal operating technique; surgical procedures are continuing to evolve and improve. groin and hip quandaries h millson sports physiotherapy, orchard view, school road, coddenham, suffolk, uk h millson, mphil sports physio, mcsp corresponding author: h millson (helen.millson@iprsgroup.com) there is little consensus on the diagnosis, pathophysiology, investigation and management of groin injuries. a key factor in making the correct diagnosis is to firstly understand the anatomy and likely generators of pain in the region. this requires an understanding of the two joints in the pelvis – the hip joint and the pubic symphysis ‒ which are at the centre of many movements. there are a multitude of varying studies on this topic. however, most importantly, many of the groin/hip pathologies can be averted by thorough and specific prehabilitation, bearing in mind the entire kinetic chain and addressing total function above and below the pelvis. s afr j sm 2012;24(4):127-128. doi:10.7196/sajsm.359 mailto:helen.millson@iprsgroup.com the evolving interventions regarding hip pathology also need to be considered. a combination of hip and pelvic injuries occurs in about 14% of the population and yet the hip has not historically always been considered as part of this aetiology. studies investigating physical tests for hips have been of poor quality, demonstrating a need for further research in this area. negative test results are of more use in ruling out the condition, given the high reported sensitivities of many tests. there are many quandaries pertaining to hip pathology. femoral acetabular impingement exists, but is not necessarily a diagnosis. the surgeon must weigh the risks of performing a potentially unnecessary procedure in an asymptomatic individual with cam morphology against the risks of allowing unchecked progression of the deleterious process. one should also bear in mind that excessive removal of acetabular labrum and ilio-femoral ligament in surgery can be detrimental.8 a most important factor for the clinician is that preliminary studies have demonstrated that having a hip joint restriction precedes the development of chronic groin injury and may be a risk factor for this condition. therefore, it may be most important to maintain range of motion in the management to prevent groin problems. future research is required to determine the extent to which physiotherapy intervention aimed at improving hip kinematics would be effective in treating individuals with labral injuries. in conclusion, it is most important to highlight the difference between an anatomical description and a functional description. further long-term studies are required as well as trials where clinical entities are correlated with systemic investigation, including mri and ultrasonography. so what is the solution to this bermuda triangle quandary? • one needs to assess how the patient’s functional movement influences both the hip and the pubic symphysis. what causes pain and where? try to understand the entire kinetic chain with its related function to the pelvis/groin/hip. then perform relevant clinical tests as well as sports-specific functional tests. clinical reasoning must be at the forefront at all times. • in spite of minimal evidence-based medicine in this regard, it seems that the most pertinent point is that many of the groin/hip pathologies can be averted by thorough and specific prehabilitation, bearing in mind the entire kinetic chain and addressing total function around the pelvis ‒ above and below. references 1. bizzini m. the groin area: the bermuda triangle of sports medicine? br j sports med 2011;45(1):1. [http://dx.doi.org/10.1136/bjsm.2010.081828] 2. verrall gm, henry l, fazzalari nl, slavotinek jp, oakeshott rd. bone biopsy of the parasymphyseal pubic bone region in athletes with chronic groin injury demonstrates new woven bone formation consistent with a diagnosis of pubic bone stress injury. am j sports med 2008;36(12):2425-2431. 3. hölmich p. long-standing groin pain in sportspeople falls into three primary patterns, a ‘clinical entity’ approach: a prospective study of 207 patients. br j sports med 2007;41(4):247-252. 4. paajanen h. ‘sports hernia’ and osteitis pubis in an athlete. duodecim 2009;125(3):261266. 5. garvey jf, read jw, turner a. sportsman hernia: what can we do? hernia 2010;14(1):17-25. 6. brukner p, khan k. clinical sports medicine. 4th ed. australia: mcgraw-hill, 2012. 7. philippon mj, decker mj, giphart je, torry mr, wahoff ms, laprade rf. rehabilitation exercise progression for the gluteus medius muscle with consideration for iliopsoas tendinitis: an in vivo electromyography study. am j sports med 2011;39(8):1777-1785. 8. abellàn j, esparza f, blanco a, et al. radiological evidence of femoroacetabular impingement in asymptomatic athletes. br j sports med 2011;45:333. [http://dx.doi. org/10.1136/bjsm.2011.084038.65] a more comprehensive list of references can be obtained from the author on request. http://dx.doi.org/10.1136/bjsm.2010.081828] http://dx.doi.org/10.1136/bjsm.2011.084038.65] http://dx.doi.org/10.1136/bjsm.2011.084038.65] sajsm vol 18 no.1 2006 3 my attention was drawn to a paper which examined the characteristics of successful journals. 1 in the study, editors of successful journals were interviewed and questioned about their views on factors which had contributed to the success of their respective journals. some of the main points arising from this study are listed below: • active recruitment of high-impact article – editors personally approached leading investigators in different research areas in their quest to attract high-quality papers to their journals. • improving services to authors – editors attempted to attract authors by speeding up the turnaround times and fast-tracking publications which had a particularly high impact. • finding niche areas – editors attempted to make their journal the definitive journal for that particular specialist area. • promoting the journals through media and other forms of communication – this characteristic was supported by a study which showed that research papers from the new england journal of medicine, which were also published and popularised in the new york times, received more scientific citations than articles which did not receive the same treatment. 3 in other words, scientific impact was improved if the work was communicated beyond the regular scientific/ clinical community. what can the south african journal of sports medicine learn from this study? while we are in a completely different league to the heavyweight journals surveyed in the study, 1 there are many practical points from the results of this study which can be considered and implemented. firstly, we need to seek and canvass for articles from top researchers and clinicians rather than waiting for articles to be submitted. at the 2008 south african sports medicine association conference in pretoria some clinicians presented fascinating case studies. most of these presentations have not been converted into publications. the possible reason for this is that the clinicians may not have had much research experience, and feel intimidated about writing the paper. this is something which can be addressed. we will commit to facilitate this process in an attempt to publish cuttingedge applied clinical and performance-related case studies. we already have structures in place to nurture young researchers who are attempting to publish their work and we will attempt to extend this to clinicians who have interesting case studies to report. secondly, we need to improve our communication with our readers, informing them about the upcoming editions and interesting articles they can look forward to reading. soon a mechanism will be in place for better communication between sasma members, so we will be able to piggyback onto this communication structure to inform members about the journal. thirdly, we will also attempt to make the reviewing process as seamless as possible and completed within four weeks. we will attempt to do this without compromising the standard of the review, as a high standard of review is essential for the quality of papers which are published. we have also decided to include a continuing medical education section in the journal, which will serve as an adjunct to the research papers. there are also possibilities about linking this continuing medical education to cpd points. fourthly, we need to develop and define our niche area. our journal needs to become the international mouthpiece for sports medicine and the allied disciplines in south africa. i think we can assume we will have achieved this goal when the south african journal of sports medicine is the first port-of-call for anyone (local or international) seeking information relevant to sports medicine in south africa. the fact that the journal has a regional niche should not be seen as an inferior option and therefore a dumping ground for a paper which has an insufficient quality for being accepted for publication in an international journal with a higher impact factor. rather, our goal should be to publish papers which have not only an international quality, but also a regional interest. indeed, the isi classification now includes a regional section catering for journals with these characteristics. another goal should be to ensure that a high proportion of the papers published are cited by other studies. it is staggering when one considers that between 1900 and 2005, 38 million papers were published in the clinical medicine and public health field. half of these papers were not cited at all by subsequent studies in the field. 2 our goal should be to ensure that any paper published in the south african journal of sports medicine does not become a statistic and is never cited again. these are not unrealistic goals. certainly the points which have been outlined above can be implemented, and there is a very good chance that in so doing the quality of the journal will be increased significantly. mike lambert editor-in-chief 1. chew m, villanueva, van der weydon m. life and times of the impact factor: retrospective analysis of trends for seven medical journals (1994 2005) and their editors’ views. j r soc med 2007; 100: 142-50. 2. garfield e. the history and meaning of the journal impact factor. jama 2006; 295: 90-3. 3. phillis dp, kanter ej, bednarczyk b, tastad pl. importance of the lay press in the transmission of medical knowledge to the scientific community. n engl j med 1991; 325: 1180-83. do we have a niche market? a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial sajsm vol 20 no. 2 2008 39 pg39 .indd 39 8/8/08 11:23:48 am original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license workloads of forward and backline adolescent rugby players: a pilot study d barnard, bsocsc; l pote, phd; c j christie, phd department of human kinetics and ergonomics, rhodes university, grahamstown, south africa corresponding author: c j christie (c.christie@ru.ac.za) rugby has become one of the fastest growing team sports in the world [1,2]. as more players participate and the seasons get longer, more injuries are being reported [1,2]. injuries (excluding catastrophic injuries and concussion) have been linked to overor undertraining [3]. there is a paucity of literature on workloads placed on adolescent rugby players and most of the understanding comes from rugby league [4]. a study on the workload of senior elite level players showed that forwards had a higher workload than backline players [5]. in contrast, phibbs et al. [6] found that in elite adolescent rugby players, backline players had higher workloads than forwards, which was similar in respective years [7,8] and lower than those placed on elite players [5] .this is most likely due to the shorter duration of match play for elite adolescents in the united kingdom which was reported to be a mean of 50 ± 44 minutes [6,7]. this is in contrast to a match duration of 80 minutes at an elite level and within senior south african schoolboy rugby (70 minutes). it must be acknowledged that elite training durations are not publicly available. according to the authors’ knowledge there has also been minimal reported research on practice durations. although the workloads on rugby players is high, priority has been given to the prevention of impact injuries rather than on managing workloads [8]. a combination of measuring internal and external loads is useful as they provide a holistic understanding of what stressors are being placed on the athlete [8]. this holistic understanding optimises training and performance [8]. using the internal, subjective measure of session rating of perceived exertion (srpe) and the external, objective measure of session duration is a very cost-effective method used to monitor an athlete’s load. this is particularly useful in a school setting because these two variables do not require specialised equipment. session rpe is typically measured using the 10point likert scale adapted by forster et al [9]. srpe is both a valid and reliable measurement for monitoring the workloads in athletes [9,10] with an error rate of 4.3% in adolescents [10]. furthermore, it is only as accurate as the player’s understanding of the scale, so adequate explanation and habituation to the scale needs to be provided [10]. the use of srpe and training duration to calculate training load also allows for the calculation of the acute:chronic ratio [3]. this ratio allows the players’ workload to be monitored throughout a season. training load can be both the acute and the chronic load placed on an athlete. acute refers to one training session load or one week’s training load [3]. chronic refers to a longer period encompassing, for example, a twoweek rolling average which is the cumulative load for two weeks of training, while a four-week rolling average is the cumulative of four weeks training [3]. the usual chronic load is a period of four weeks; however, the two-week chronic load can be used as it has been used in the purpose of return-to-play protocols [3]. an optimal acute:chronic ratio is between 0.8 and 1.3 [3] which is referred to as the ‘sweet spot’ which is where injury risk is purported to be at its lowest [3,8,11]. when the ratio is 1.5 or higher it is referred to as the ‘danger zone’ which has a high injury risk [3,11]. when the ratio is below 0.8 the athletes are at a point where they are undertraining, thus leading to a higher risk of injury [3]. recent research has shown that there are conflicting views regarding the acute:chronic ratio and whether or not it is actually a good predictor for injury. a new method uses an exponentially weighted moving average, which places more emphasis on recent workload compared to the whole period’s workload [12]. however, the rolling average method is more appropriate for a school setting as it considers the whole portion of load [3]. it is evident that workload monitoring may be an effective tool to monitor fatigue and injury risk in athletes [8]. however, there are only a few studies which have attempted to measure workloads on adolescent rugby players and none, to theses authors’ knowledge, within a south african context. therefore, the purpose of this study was to determine the workloads placed on adolescent rugby players in the in-season period. this serves as a pilot study to prepare for future studies on this topic. background: there is minimal research on workloads of adolescent rugby players. therefore, the main aim of this study was to determine the workloads placed on a cohort of south african adolescent rugby players (n = 17), during an inseason period. methods: session rpe ratings were collected daily, 30 minutes after the training session concluded, during an 11-week inseason period. the training load was calculated as the session ratings of perceived exertion multiplied by the session’s duration (min). results: the main finding of the study was that the adolescents in this investigation had similar workloads to elite players but higher workloads than other studies on adolescent rugby players. the forwards (3311±939 arbitrary units; au) had a higher workload than backline players (2851±1080 au). there was no difference between forwards and backline players with regards to the acute:chronic workload ratio. conclusion: workloads are high in these adolescent players, particularly in the forwards, and are similar to the workloads of elite level rugby players. keywords: rugby union, session rating of perceived exertion, workload monitoring, ac ratio, cost effectiveness s afr j sports med 2020;32:1-5. doi: 10.17159/2078-516x/2020/v32i1a7427 mailto:c.christie@ru.ac.za http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7427 https://orcid.org/0000-0003-1371-2616 https://orcid.org/0000-0003-0727-0014 https://orcid.org/0000-0002-5608-9943 original research sajsm vol. 32 no. 1 2020 2 methods players in this study a convenience sample from a private school in grahamstown, south africa was used. the sample included seventeen male, first team squad players between the ages of 16 to 19 years (stature: 1.74 m; mass: 77.4 kg). the study was approved by the rhodes university ethical standards committee for research involving human participants (1075008). approval was obtained from the school and written informed consent was obtained from all players over the age of 18 years. written consent was obtained from the parents of those players under the age of 18 years. furthermore, players were also required to provide assent. study design the study was a prospective cohort study which measured match and training load (srpe and session duration) daily, 30 minutes after the end of the training session, over eleven weeks during the in-season period. the in-season period was used for pragmatic reasons, as prior to this, players were on holiday or participating in other sports. although adolescent rugby union players can train all year round, the data collection period in this study was selected to represent the normal south african school rugby competitive season. there was no minimum duration required for training or matches and all were included in the analyses. collection period in-season data were obtained daily during the 11-week period. during this period there was only one other sport that could be played, namely hockey. these workloads were included in the total weekly load for the relevant players. workloads monitored session rpe and duration of the session where used respectively to calculate workload. the rpe scale used was the adapted version by forster et al. [9]. participants were provided with a hard copy of the scale and were required to rate their effort for perceived exertion thirty minutes after the conclusion of the session. this delay was to ensure that the measurement reflected the whole session and not only the intensity of the last activity performed. the duration of the session was timed by the coach, from the moment the warmup started until the cooldown finished. measurements and quantifications session rpe and session duration were used to calculate training or match load as follows [9]: equation 1 training load (tl) = session rating of perceived effort (srpe) x duration of session (minutes) the acute:chronic ratio was calculated by dividing the acute load by the chronic load. in this case the acute workload consisted of one week’s load and the chronic load referred to two weeks of accumulative load. equation 2 acute:chronic (a:c) = acute load / chronic load the two-week rolling average was used to allow for sufficient data points for comparative purposes as the data collection period was only eleven weeks. however, it is noted that the four-week rolling average is the optimal average to use and is a limitation of the current study. procedures there was a four-week habituation period before the start of the study. the participants were habituated to the session rpe scale after every practice or activity completed. the rating took place thirty minutes after the practice or match. time of session was manually recorded by the researcher. the sessions included all the sports players’ participation in and any other training they undertook, which varied from player to player. the focus of this period was to ensure the players understood ratings of perceived effort. thereafter, for the 11-week inseason period, times of their daily match or training sessions and srpe were recorded. statistical analysis all data were entered to a customised spreadsheet (microsoft excel, microsoft, redmond, usa). daily data were summated to provide weekly player match and training loads, as well as to quantify week-by-week changes of acute:chronic workload ratios. analyses were done in r 2.14. [13]. the data were not normally distributed. a kruskal-wallis test and one-way anova were used to compare forwards versus backline players. cohen’s d effect sizes (es) were used to establish the degree of difference between forwards and backline players, as well as between match and practice data. the criteria that were used for interpreting effect size was <0.2 trivial, 0.2-0.6 small, 0.6-1.2 moderate, 1.2-2.0 large, and > 2.0 very large [14]. significance was set at p<0.01. fig. 1. mean  standard deviation overall workloads of forwards and backline players over an 11-week period. * indicates significance (p<0.01). original research 3 sajsm vol. 32 no. 1 2020 results practice duration (86.05  33.54 minutes) was longer than the match duration (75.09  19.90 minutes), with an effect which was small (es=0.35). this was despite the fact that srpe was lower for practices (6.3  1.7 au) compared to matches (7.2  1.6 au), with a small effect (es=0.53). overall, workload for the 11-week period was significantly higher (p<0.01; es=0.86) for the forwards compared to the backline players (fig. 1). in contrast, there was no intra-week difference or differences between positions (fig. 2). the mean workload for backs was 2507  928 au and 3311  939 au for the forwards. the mean workload for all the players was 2851 ± 1080 au. workloads varied weekly for both forwards and backs (fig. 3). the mean acute:chronic ratio for the backs and forwards during the 11-week period was the same at 0.97 (es=0.01) with a standard deviation of  0.21 for the backs and  0.23 for the forwards (fig. 4). week 1 was significantly (p<0.01) higher compared to all the other weeks and thereafter there was no difference (fig. 4). there was a total of 170 observations represented as acute:chronic ratios (fig. 5). there were 20 observations (12%) that were not considered in the ’sweet spot’ (0.8-1.3) [3] and there were only six observations (4%) that were above the ’sweet spot’. therefore, there were 144 observations (85%) in the recommended zone. there were only three players that remained in the ’sweet spot’ throughout the 11-week period. fig. 3. mean ± standard deviation individual weekly acute:chronic ratio differences between forward and backline players. fig. 4. mean ± standard deviation overall acute:chronic ratio between forwards and backline players over an 11-week period. fig. 2. weekly mean ± standard deviation workload (au) differences between forward and backline players. original research sajsm vol. 32 no. 1 2020 4 in summary the forwards had a significantly higher workload than backline players but acute:chronic ratios were similar. discussion the most important finding of this study was that workloads were similar to those placed on elite level players [5,6]. furthermore, and similar to other studies, forwards had higher overall workloads compared to backline players [5]. another important finding was that the mean workload of all players in this study (2851 ± 1080 au) was higher than that of previous studies on adolescent players [6,7]. it should be noted, that the players in the phibbs et al.[6] study, were classified as elite adolescent players who were part of an academy, whereas the players in this and the phibbs et al.[7] study were schoolboys. this is definitely an area that requires further investigation to determine whether rugby players at school level in south africa have higher injury prevalence and whether this could be linked to workloads. or whether countries like the united kingdom could increase workloads to help the body better adapt. this is an interesting debate as it may also be linked to retention into senior level rugby. higher workloads at school level may be a deterrent to continuation into higher levels of rugby. the fact that forwards experience more load than backs is not unexpected as studies on adolescent [8] and adult players respectively [5] have found that forwards are involved in more high intensity activities. this has been directly assessed in elite adult forwards who were reported to have a higher energy expenditure than backline players [5]. forwards are also involved in more static bouts as a result experience higher workload [15]. anecdotally there is the perception that south african rugby favours a more forwards-based game, which relies on the size and power of forwards to drive a game compared to other countries. this may partly explain why forwards in this study had a greater load as this type of strategy is also favoured at the adolescent level. interestingly, other studies at the non-adolescent level have also reported higher workloads in forwards compared to backs [5], which is in contrast to phibbs et al.[6] who reported higher workloads in backline players at the adolescent elite level. this is clearly something that needs to be investigated further. a possible reason for this contrast is that the rugby structures for adolescents in south africa could be different to the structures in other countries. also, the structures for non-elite adolescents may be different to those at an elite level. when looking at overall workload in this study (2850 ± 1080 au), it is higher than reported by phibbs et al. [6,7] (1217 ± 367 au and 1210 ± 571 au respectively). the most likely reason for this is the differences in practice and, particularly, match duration. the players in this study had a longer mean match time (76 vs. 50 minutes) and similar practice time (172 vs. 178 minutes per week) compared to the players in the phibbs et al. study [7] . why this is the case is not known but it is something that needs to be considered and investigated further, as this may be a way in which workloads can be optimised at the adolescent level to ensure that player injuries are minimised. most players were within the ‘sweet spot’ range which is in contrast to the players in the study of phibbs et al.[7]. the findings show that a higher percentage (85%) of observations were in the zone compared to phibbs et al.[7] who had 60% observations in this range. three players in this study remained continuously in the zone, which is in contrast to phibbs et al. [7] who showed that no players were consistently in the zone. compared to phibbs et al. [7] the current study had few players both above (4% vs. 13%) and below (12% vs. 26%) the ’sweet spot’. this suggests the current cohort was optimally managed in terms of workload. it must be noted that there were two participants who had an injury during the 11-week period. the first participant (forward player) had a concussion during a match in week fig. 5. total acute:chronic ratios for individual players over an 11-week period. original research 5 sajsm vol. 32 no. 1 2020 three which then prevented him training in the weeks thereafter. this player thus had very low acute:chronic ratios during weeks four and five respectively (fig. 5). the second participant (backline player) was injured during a hockey match in week seven which prevented him from training during week eight, so he had an acute:chronic ratio of zero in that week (fig. 5). with both players missing practices, it caused a decrease in acute:chronic ratios and these players fell below the ’sweet spot’ (fig. 5). as to be expected, they had a spike in their acute:chronic ratios during weeks six and nine respectively, which was their return-toplay week (fig. 5). conclusion in conclusion, this study found that most players were training within the recommended range [3]. however, their workloads were as high as elite level players and particularly high in the forwards. this is something that needs to be monitored and managed by both coaches and medical teams. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: db and cjc were involved in all stages of the research including conception, design, analysis and interpretation of data, drafting and critical revision for important intellectual content and approval of the version to be published. lp was involved with drafting and critical revision for important intellectual content and approval of the version to be published. references 1. quarrie kl, raftery m, blackie j, et al. managing player load in professional rugby union: a review of current knowledge and practices. br j sports med 2017;51(5):421-427. [https://doi.org/10.1136/bjsports-2016-096191] pmid:27506436] 2. hartwig tb, naughton g, searl j. defining the volume and intensity of sport participation in adolescent rugby union players. int j sport physiol. 2008 mar 1;3(1):94-106. [https://doi.org/10.1123/ijspp.3.1.94] [pmid:19193957] 3. gabbett tj, hulin bt, blanch p,et al. high training workloads alone do not cause sports injuries: how you get there is the real issue. br j sports med 2016, 50(8), 444-445. [https://doi.org/10.1136/bjsports-2015-095567] [pmid:26795610] 4. gabbett tj, domrow n. risk factors for injury in subelite rugby league players. am j sports med 2005 mar;33(3):428-434. [https://doi.org/10.1177/0363546504268407] [pmid:15716260] 5. bradley wj, cavanagh b, douglas w, et al. energy intake and expenditure assessed 'in-season' in an elite european rugby union squad. eur j sport sci 2015;15(6):469-479. [https://doi.org/10.1080/17461391.2015.1042528] [pmid:26055695] 6. phibbs pj, jones b, roe g, et al.. organized chaos in late specialisation team sports: weekly training loads of elite adolescent rugby union players. j strength cond res 2018;32(5):1316-1323. [https://doi.org/10.1519/ jsc.0000000000001965] [pmid:29683915] 7. phibbs pj, jones b, roe g, et al. the organised chaos of english adolescent rugby union: influence of weekly match frequency on the variability of match and training loads. eur j sport sci 2018;18(3):341-348. [https://doi.org/10.1080/17461391.2017.1418026] [pmid:29303682] 8. bourdon pc, cardinale m, murray a, et al. monitoring athlete training loads: consensus statement. int j sport physiol 2017;12(suppl2):s2161-s2170. [https://doi.org/10.1123/ijspp.2017-0208] [pmid:28463642] 9. foster c, florhaug ja, franklin j, et al. a new approach to monitoring exercise training. j strength cond res 2001;15(1):109115. [https://doi.org/10.1519/00124278-200102000-00019] [pmid:11708692] 10. phibbs pj, roe g, jones b, et al. validity of daily and weekly selfreported training load measures in adolescent athletes. j strength cond res 2017;31(4):1121-1126. [https://doi.org/10.1519/ jsc.0000000000001708] [pmid:28328718] 11. windt j, gabbett tj. how do training and competition workloads relate to injury? the workload-injury aetiology model. br j sports med 2017;51(5):428-435. [https://doi.org/10.1136/bjsports-2016096040] [pmid:27418321] 12. murray nb, gabbett tj, townshend ad, et al. calculating acute: chronic workload ratios using exponentially weighted moving averages provides a more sensitive indicator of injury likelihood than rolling averages. br j sports med 2017;51(9):749-754. [https://doi.org/10.1136/bjsports-2016-097152] [pmid:28003238] 13. r core team. r: a language and environment for statistical computing. 20133(1). 14. hopkins wg. how to interpret changes in an athletic performance test. sportscience 2004; 8: 1-7. 15. roberts sp, trewartha g, higgitt rj, el-abd j, stokes ka. the physical demands of elite english rugby union. j sports sci 2008;26(8):825-833.[https://doi.org/10.1080/02640410801942122] [pmid:18569548] file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%20/10.1136/bjsports-2016-096191 doi://10.1123/ijspp.3.1.94: https://doi.org/10.1136/bjsports-2015-095567 https://doi.org/10.1177/0363546504268407 https://doi.org/10.1080/17461391.2015.1042528 https://doi.org/10.1519/%20jsc.0000000000001965 https://doi.org/10.1519/%20jsc.0000000000001965 https://doi.org/10.1080/17461391.2017.1418026 https://doi.org/10.1123/ijspp.2017-0208 https://doi.org/10.1519/00124278-200102000-00019 https://doi.org/10.1519/%20jsc.0000000000001708 https://doi.org/10.1519/%20jsc.0000000000001708 https://doi.org/10.1136/bjsports-2016-096040 https://doi.org/10.1136/bjsports-2016-096040 https://doi.org/10.1136/bjsports-2016-097152 https://doi.org/10.1080/02640410801942122 original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license reliability of the isometric mid-thigh pull peak force in irish schoolboy rugby players d o’dowd hill, bsc; ca lodge, dpt, msc; dt browne, msc healthcore, institute of technology carlow, carlow, ireland corresponding author: d o’dowd hill (diarmuid.odowd-hill@itcarlow.ie) rugby union is an intermittent collision sport, in which maximal muscular strength is of importance.[1] this importance is due to the relationships between increased maximal strength and improvements in both dynamic performance and rugby specific skills, such as jumping, sprinting, scrummaging, tackle success rates, and line break rates.[1, 2] increased maximal strength also has the ability to reduce injury rates and improve psychosocial wellbeing in athletes.[2, 3] the importance of maximal strength in rugby union is not limited to the adult game (>u20). this is apparent when you consider that maximal strength is a distinguishing factor between playing positions, age grades and playing levels in youth rugby union.[4, 5] therefore, one must assume that the monitoring and testing of maximal strength should be a priority when dealing with youth rugby players across the development pathway. maximal strength can be defined as the ability to exert maximal force against an external resistance and requires a maximal voluntary contraction.[6] within youth sports, this has previously been measured through the use of repetition maximum testing, during which a participant is instructed to complete multiple sets of increasing weight for a prescribed number of repetitions per set until failure.[7] more recently, portable force plates and specialist isometric racks have become cheaper and more accessible. this has allowed isometric maximal strength testing to become more common in both practical and academic settings.[8] this is also due to the proposed benefits of increased safety, lack of familiarisation needed, decreased fatigue and high reliability when compared to the more conventional resistance-based lifts, such as, squat, bench press and deadlift.[9-11] the isometric mid-thigh pull (imtp) is an isometric means of testing maximal strength which has previously been shown to be reliable (interclass correlation coefficient (icc) >0.90, coefficient of variation (cv%) <10%) and valid (1rm squat, r=0.86; counter movement jump (cmj), r=0.82) irrespective of previous cohorts used.[11] to date, no studies have investigated the reliability of the imtp pf within grassroots schoolboy rugby union. previous studies investigating imtp pf in rugby union have taken place with older elite cohorts (u16+). [4, 12] the imtp is designed to mimic the second pull of the clean, which is the phase which generates the highest peak force during the movement.[13] there are strong associations between imtp peak force (imtp pf) and other dynamic resistance-based movements, such as the olympic lifts, squats and deadlifts.[9, 11, 14] further evidence of the utility of the imtp pf to rugby is apparent when it’s associations with improved dynamic movements and rugby-specific skills are considered.[1, 11, 15] although most of these studies are limited to adult cohorts, there also exists known links between the imtp pf and dynamic performance for youth, indicating its relevance irrespective of age.[15] the current study aims to investigate the reliability of the imtp pf with respect to irish schoolboy rugby union. the objectives undertaken by this study were to (1) investigate the intra-day reliability of the imtp pf with respect to the three age-grades of irish schoolboy rugby union (2) investigate the inter-day reliability of the imtp pf within irish schoolboy rugby union. methods study design the current study used an observational cross-sectional design. all male rugby players within an irish secondary school, participating in the connacht schools u14, junior and senior competitions were invited to participate. consent was sought from a legal guardian following an open invitation information night. all participants were required to attend the after-school gym session which testing took place. anthropometric measurements of height (cm) and mass (kg) were investigated across the chronological age grades. isometric mid-thigh pull reliability (icc & cv%) was investigated intraand inter-day, background: maximal strength is a key variable within youth rugby union and is therefore of merit when testing and monitoring youth rugby athletes. isometric mid-thigh pull peak force (imtp pf) has been observed to be a reliable, valid, and safe means of assessing maximal strength in previously researched cohorts. currently, there exists a distinct lack of literature with regards to the use of imtp pf with non-elite youth athletes. objectives: (1) investigate the intra-day reliability of the imtp pf with respect to the three age-grades of irish schoolboy rugby union, (2) investigate the inter-day reliability of the imtp pf within irish schoolboy rugby union. methods: the current study utilised self-selected body positions of 84 non-elite schoolboy rugby union athletes (age: 14.7 ±1.7 years; height: 170.6 ±10.3 cm; mass: 63.9 ±14.8 kg). results: imtp pf was observed to be a reliable measure of peak force both interand intra-day (intra-day: coefficient of variation 3.3%; interclass correlation coefficient 0.99; 95% confidence interval 0.99 – 1.00; inter-day: coefficient of variation = 5.1%; interclass correlation coefficient 0.99; 95% confidence interval 0.98 – 1.00). a change of 10.9 kg should be deemed worthwhile when working with irish schoolboy rugby players. conclusion: the imtp pf is a safe and reliable measure of maximal strength in non-elite youth rugby athletes. keywords: team sports, imtp, youth, maximal strength s afr j sports med 2021;33:1-5. doi: 10.17159/2078-516x/2021/v33i1a9433 mailto:diarmuid.odowd-hill@itcarlow.ie http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9433 https://orcid.org/0000-0002-5787-5153 https://orcid.org/0000-0001-5237-2322 https://orcid.org/0000-0001-6050-2916 original research sajsm vol. 33 no. 1 2021 2 with inter-day testing being undertaken by a representative cohort one week after intra-day testing. participants eighty-four participants from the three age-grades (u14; junior, u16; senior, u19) elected to take part in the study and met all the inclusion criteria. ethical approval was granted by the relevant ethics board in accordance with the declaration of helsinki. the participant’s mean chronological age, height and mass were age, 14.7 ±1.7 years; height, 170.6 ±10.3 cm; mass, 63.9 ±14.8 kg. of the 84 participants, 10 participants were retested to allow for inter-day reliability testing (table 1). procedures participants wore normal gym clothing during testing. immediately upon entering the gym, body mass was measured using a portable scale (seca, germany). standing and seated height were then measured using a portable stadiometer (seca, germany). following the anthropometric measurements, a standardised 10 minute dynamic warm-up was completed. isometric mid-thigh pull (imtp) was then measured using a portable force plate (hurlabs, finland). a protocol consisting of three sessions, each one week apart was utilised (figure 1). the first session was a familiarisation session, which consisted of three maximal efforts of the imtp with a three-minute rest period between trials. the second session was the first full testing session and was used to test intra-day reliability. the third session was the second full testing session and was used to test inter-day reliability. during the full testing sessions, two warm-up repetitions were completed at 50% and 75% self-rated intensity respectively, with a three-minute rest period between each warm-up trial. all participants then completed three trials at 100% intensity, with a five minute rest period between each of the three trials. the protocol for the warm-up and testing trials is outlined below (fig. 1). isometric mid-thigh pull peak force (imtp pf) imtp pf has previously been reported as reliable (cv≤4.3%, icc>.92), valid and responsive to resistance training, irrespective of previously tested cohorts.[11] all imtp pf data were collected at 1 000 hz using a portable force plate (force platform fp8 2003, hurlabs, finland), which was placed under a fixed bar. all data were extracted using the corresponding software suite provided with the force plate (hurlabs force platform software suite 2.65.5.6, hurlabs, finland). the force plate was zeroed between all participants. during testing, the participants were asked to selfselect a body position from which they ’felt comfortable to pull as hard as possible’, with the bar being in a fixed position at ’mid-thigh’ (halfway between the patella and iliac crest). the use of a selfselected body position during isometric mid-thigh pull peak force testing has been shown to be reliable (icc=.99), as well as having a small effect (cohen d=.037) when compared to eight other body positions.[10] bar height was visually verified as being acceptable by the lead supervisor. minimal pre-tension was allowed to ensure that there was no slack in the body prior to the initiation of the pull. the participant was then instructed to ’pull as hard and fast as possible’ for five seconds once the verbal cue of ’go!’ was given by the lead examiner. during the trial, the lead examiner verbally counted down the trial time aloud; ’five, four, three, two, one’, before giving acknowledgment of completion of the trial by shouting ’stop’. statistical analysis all descriptive statistics were computed by spss (ibm, v.25, 2017) and microsoft excel (microsoft, 2010) from the data set. all variables were calculated for the overall cohort and with respect to the age-grades. through the use of a kolmogorovsmirnov test the data was deemed to be normally distributed. intraand inter-day random variability was determined using mean coefficients of variation (cv%) and intra-class correlation coefficients (iccs) (2,1) to determine both absolute and relative reliability. acceptable thresholds were determined using a cv of ≤ 10%.[16, 17] ninety-five percent confidence intervals were calculated for all variables. magnitudes of icc were classified according to the following thresholds: 0.9 nearly perfect; 0.7– 0.9, very large; 0.5–0.7, large; 0.3–0.5, moderate; and 0.1–0.3, small.[16] standard error of the mean (sem) and smallest table 1. analysis of cohort intra-day (n) inter-day (n) overall  84 10 u14  29 0 junior (u16) 32 5 senior (u19) 23 5 fig. 1. the protocol for the warm-up and testing trials. session 1: week 1 familiarisation session (n=84) 3 maximum effort trials with 3-minute rest periods session 2: week 2 intra-day testing session (n=84) 50% effort trial with 3-minute rest 75% effort trial with 5-minute rest 3 maximum effort trials with 5-minute rest periods session 3: week 3 inter-day testing session (n=10) 50% effort trial with 3-minute rest 75% effort trial with 5-minute rest 3 maximum effort trials with 5-minute rest periods 10 participants were selected randomly to attend session 3 original research 3 sajsm vol. 33 no. 1 2021 worthwhile change (swc) were also calculated to allow for inferences to be made about the variability and practical application of the imtp pf. results intra-day reliability (table 2 and fig. 2) the imtp pf exhibited a nearly perfect icc across all age-grades for intraday testing (icc ≥ 0.97; 95% ci ≥ 0.94 ≥ 0.98). the cv% was also below the threshold of acceptability for all age-grades (cv% ≤ 3.7%). the imtp pf had a sem of 5.9 kg and a swc of 10.9kg. inter-day reliability (table 3 and fig. 3) the imtp pf exhibited a nearly perfect icc across the two testing sessions (%; icc 0.99; 95% ci 0.98 – 1.00). the cv% was also below the threshold of acceptability for all agegrades (cv% = 5.1%). discussion the current study aimed to investigate the reliability of the imtp pf within irish schoolboy rugby union. while using a self-selected body position, with one familiarisation session, the imtp pf was reliable both intraand inter-day with respect to the irish schoolboy rugby union. reliability with respect to intra-day reliability, the imtp pf for the overall cohort had nearly perfect icc values (icc 0.99; 95% ci 0.99 – 1.00) and had a cv% well below the acceptable threshold (3.3%). this indicates that the imtp pf is a reliable measure when considering the maximal isometric strength of schoolboy rugby players. this is in agreement with previous studies on youth rugby union players, which observed the icc and cv to be 0.97 and 3.5% respectively.[4] although, this study was carried out on elite youth from u16, u18, and u21, it utilised prescribed hip and knee angles. it is therefore promising that the reliability measures of the imtp pf were improved upon slightly when using self-selected knee and hip angles within a younger, non-elite cohort of rugby union players. when compared to intra-day, the inter-day reliability of imtp pf maintained its nearly perfect icc values (icc 0.99; 95% ci 0.98 – 1.00), while cv% increased to 5.1%. although there are no studies assessing the inter-day reliability of the imtp pf in youth rugby players, the current study is in contrast with a study conducted on elite youth footballers with an age of 18.4 years±2 years.[18] musham’s study took four testing sessions to achieve comparable reliability (cv% = 5.8%; icc 0.88; 95% ci 0.77 – 0.94). although comparisons with this study must be done cautiously as limitations may be apparent. during musham’s study, a ’minimum of two trials’ was completed by each participant interspersed by 30-second rest periods between each maximum effort trial. due to this lack of recovery, table 2. intra-day reliability (n=84) trial 1 (kg) trial 2 (kg) trial 3 (kg) cv% icc (95% ci)  overall (n=84) 180.6 ± 54.3 180.5 ± 55.2 178.2 ± 54.1 3.3 0.99 (0.99 – 1.00) u14 (n=29) 133.0 ± 21.9 132.9 ± 24.5 131.6 ± 22.7 3.7 0.97 (0.94 – 0.98) junior (u16) (n=32) 186.6 ± 37.6 187.0 ± 42.3 184.4 ± 42.2 3.0 0.99 (0.98 – 0.99) senior (u19) (n=23) 242.3 ± 36.7 241.4 ± 34.5 238.0 ± 33.6 3.1 0.97 (0.94 – 0.99) data are expressed as mean ± sd unless indicated otherwise. cv%, coefficient of variation; icc, interclass correlation coefficient; ci, confidence interval. fig. 2. comparative intra-day scatterplot for the whole cohort (n=84) with lines of best fit. table 3. inter-day reliability (n=10) trial 1 (kg) trial 2 (kg) trial 3 (kg) trial 4 (kg) trial 5 (kg) trial 6 (kg) cv% icc (95% ci) overall (n=10) 203.4 ± 51.1 200.8 ± 51.7 195.4 ± 41.1 214.5 ± 52.2 202.1 ± 46.5 202.6 ± 49.1 5.1 0.99 (0.98 – 1.00) data are expressed as mean ± sd unless indicated otherwise. cv%, coefficient of variation; icc, interclass correlation coefficient; ci, confidence interval. trial 1 to 3 took place on day 1, while trial 4 to 6 took place on day 2. original research sajsm vol. 33 no. 1 2021 4 fatigue may be a confounding factor when trying to measure reliability for isometric strength protocols.[19] it is therefore surprising that the recommendations arising from musham’s study are that a minimum of four sessions comprising of six trials per session with five minute rest periods are needed to achieve adequate reliability when working with novice athletes.[18] age grade the current study was the first to assess the reliability of individual age grades with respect to the imtp pf. the reliability was high across all three age grades. the junior cohort had the highest reliability (cv% = 3.0%; icc, 95% ci; 0.99, 0.98 – 0.99), followed by seniors (cv% = 3.1%; icc 0.97; 95% ci 0.94 – 0.99), and u14s (cv% = 3.7%; icc 0.97; 95% ci 0.94 – 0.98). both the reliability of the three groups and trend of the junior group being of the highest reliability are in contrast with inferences made in previous studies which cited training age as a confounding factor in the reliability of the imtp pf in youth athletes.[16, 18] limitations the current study only assessed inter-day reliability across two days, with a relatively small cohort. this may limit the ability to test systematic bias across multiple testing dates. the lack of inclusion of u14 participants within the inter-day testing may also be a limitation. practical application with regard to schoolboy rugby players, the imtp pf is a highly reliable measure of maximal strength irrespective of chronological age. this is true for both interand intra-day. the use of a single familiarisation session and self-selected body position is sufficient with respect to reliability and may therefore be utilised when assessing youth athletes. the current study’s results also indicate that a single trial may also be sufficient when measuring peak force. a change of 10.9kg should be deemed worthwhile when working with irish schoolboy rugby players. the adoption of these methods may allow for practitioners to test and monitor large groups of youth rugby athletes in a time-efficient and safe manner. conclusion a single trial of the isometric mid-thigh pull with a selfselected body position is a reliable measure of both intraand inter-day maximal strength in non-elite schoolboy rugby athletes. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: d o’dowd hill contributed to the conception, design, analysis, interpretation of data, drafting, and approval of the version to be published. c lodge and d browne contributed to the conception, critical revision, and approval of the version to be published. references 1. cunningham dj, shearer da, drawer s, et al. relationships between physical qualities and key performance indicators during match-play in senior international rugby union players. plos one 2018;13(9):e0202811. 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[doi: 10.1519/jsc.0000000000002566] [pmid: 29547490] 17. cormack sj, newton ru, mcguigan mr, et al. reliability of measures obtained during single and repeated countermovement jumps. int j sports physiol perform 2008;3(2):131-144. [doi: 10.1123/ijspp.3.2.131] [pmid: 19208922] 18. musham c, fitzpatrick jf. familiarisation and reliability of the isometric mid-thigh pull in elite youth soccer players. sports perf sci reports 2020;;85:1-4. 19. trossman pb, li p-w. the effect of the duration of intertrial rest periods on isometric grip strength performance in young adults. otjr: occupation, participation and health 1989;9(6):362-378. [doi:10.1177/153944928900900604] [pmcid: 22973420] sajsm 551.indd original research sajsm vol. 26 no. 4 2014 115 background. declining levels of physical activity coupled with the rising incidence of childhood obesity in developing countries are of health concern. current daily recommendations for preadolescent children are to accumulate 60 min of moderate physical activity per day. in south africa, physical education forms part of the life skills curriculum, but children have limited school time to engage in physical activity. as many obesogenic behaviours are learnt in childhood and track into adulthood, physical activity should be promoted at a young age and should be a research priority. objectives. to explore and determine the association between body mass index (bmi) and daily physical activity levels as expressed in metabolic equivalent of task (met) in 7 10-year-old children in quintile-5 english-medium primary schools in port elizabeth. methods. a quantitative, descriptive, one-way, cross-sectional design utilising random sampling was used. a once-off survey comprised anthropometric assessment of height and weight of 713 participants. ageand gender-specific prevalence rates of overweight, obesity and underweight were calculated based on the international obesity task force (iotf) cut-off points. one-way analysis of variance (anova) and χ2 tests were performed. a validated once-off interviewer-administered physical activity questionnaire was utilised to determine daily energy costs. results. the bmi of the majority of children fell within the norm and was coupled with high levels of daily physical activity (average of 893 mets). no significant relationship was found for bmi and physical activity (p=0.8). conclusion. daily level of physical activity is not significantly related to bmi in urban children from an economically privileged setting. s afr j sm 2014;26(4):115-118. doi:10.7196/sajsm.551 body mass index and associated physical activity levels in 7 10-year-old children in primary schools in port elizabeth m l baard, dphil; j m mckersie, ma (human movement science (research)) department of human movement science, school of lifestyle sciences, faculty of health sciences, nelson mandela metropolitan university, port elizabeth, south africa corresponding author: m l baard (maryna.baard@nmmu.ac.za) physical inactivity in young children is of concern because of the increasing prevalence of obesity, type 2 diabetes mellitus, cardiovascular disease and lack of fitness, which are precursors of adult chronic disease. [1] excessive adiposity is caused mainly by an imbalance between energy intake and energy expenditure. multiple factors are interrelated and contribute to the complexity of obesogenic behaviour. [2] physical activity improves cardiovascular fitness, body composition, blood lipid levels, and skeletal and psychological health in young children.[3] south africa (sa) has the 4th highest prevalence of physical inactivity in africa when assessed by global surveillance questionnaires. [4] the sa youth risk behaviour survey reported that less than a third of young children surveyed participated in physical activity, and ~42% fell short of the minimum standardised recommendation, [5] and sa children have among the highest prevalences of overweight (preobesity) and obesity globally and in sub-saharan africa. [6] health recommendations for preadolescent children are to accumulate at least 60 min of physical activity daily or to engage daily in moderate to vigorous physical activity for at least 50% of physical education class time in school.[7] currently in sa, due to restructuring of the school curriculum, physical education has lost formal instruction time to the life skills subject. therefore, children have limited opportunity to engage in the recommended daily amount of physical activity in order to benefit from a healthy lifestyle and prevent premature onset of chronic disease. the health of the nation study[8] pleads for the reintroduction of physical education as a separate school subject and reiterates the need for enhancing physical fitness among school children. the prevalence of childhood obesity in developing countries is associated more with children from a higher socioeconomic background than their less economically privileged counterparts.[9] according to rossouw et al.,[6] relevant published studies in higher socioeconomic prepubertal children in sa are scarce, as most researchers have focused on undernutrition in rural areas. it was thus deemed important to explore and determine associated physical activity levels based on recently acquired anthropometric data for 7 10-year-old urban children in financially privileged (quintile 5) english-speaking primary schools, in port elizabeth in the eastern cape province. methods a descriptive, one-way, cross-sectional research design with baseline anthropometric measures of weight and height was used.[10] body mass index (bmi) was calculated for each child. table 1 displays the range of grades, bmi scores and z-scores according to which the children were categorised using the international obesity task force (iotf) method. [11] physical activity was measured using an interviewer-administered physical activity questionnaire (paq) as a validated assessment tool for sa primary-school children.[12] daily physical activity levels were reported with assistance from parents or guardians. the metabolic equivalent of task (met) was used to assess daily energy expenditure during activities.[13] the nelson mandela metropolitan university (nmmu) research ethics committee: human approved the study (h12-hea-hms-002). the nmmu department of education provided a list of all 109 primary schools in port elizabeth, of which 28 were quintile 5 116 sajsm vol. 26 no. 4 2014 english-medium primary schools. randomised sampling was used to select 10 schools from which to sample participants.[10] only four of the principals gave voluntary consent to participate in the study. the target population comprised 713 7 10-year-old children. rationale for inclusion of this age group was that body mass was unlikely to be affected by developmental changes associated with puberty or infancy. demographic data pertaining to age, gender, ethnicity and home language of the children are presented in table 2. for statistical analysis, four of the participants were excluded based on the home language variable, as they fell outside the inclusion criteria for this study. therefore, the total sample population comprised 709 children. a booklet containing the paq and demographic information was given to the children by their teacher, to be completed by parents or guardians a week prior to the scheduled anthropometric assessments. parental informed consent and assent forms for children to be signed prior to voluntary participation were included in the booklet. anthropometric measurements of weight and height were reported in the booklet for every participant. trained postgraduate research assistants did the measurements in private classroom settings and completed assessments within 1 month of appointment times. children were measured according to school grade and gender. assessment methods were explained to the children to familiarise them with the measurements and to reduce any uncertainty or anxiety among them. standardised protocol of the american college of sports medicine[14] was used to do assessments. the anthropometric instruments were calibrated prior to measurement at all four schools. height was measured to the nearest 0.1 cm using a charder hm 200 pw stadiometer (charder medical, taiwan). children stood barefoot in the anatomical zero position, and height was recorded in the midsagittal plane from the soles of the feet to the vertex. a scalemaster jadever model jwi scale 86 (scalemaster, taiwan) was used to measure weight to the nearest 0.01 kg. the children were barefoot and wore minimal clothing. they had to stand still while being measured, with body weight distributed equally between their feet. physical activity was expressed in terms of met to calculate energy spent during activities.[13] met is defined as the ratio of metabolic cost during an activity to a reference metabolic rate of 3.5 ml o2.kg -1.min-1 and is equivalent to 1 kcal.kg-1.h-1 or 4.184 kj.kg-1.h-1.[13] quantitative data analysis was done by means of the statistica version 9.0 computer processing package (statsoft inc., usa).[15] variables of age, gender, bmi (z-scores) and met levels were reported as means and standard deviations (sds). one-way analysis of variance (anova) determined whether statistical differences existed for bmi and met levels. chi-square tests established where these differences existed for the age cohorts and the selected variables. significance was accepted at p<0.05. results height, weight and bmi of the children have been reported and discussed in detail elsewhere.[16] table 3 illustrates descriptive data obtained for bmi and met levels for the total group. descriptive results indicate that 65% of the children were of normal weight, 21% were overweight, 10% were obese and 4% were underweight (fig. 1). the highest prevalence of overweight (25%) was found in children aged 10, and the highest incidence of obesity (13%) was found in 8-year-old children. results analysed for gender effect showed that 19% of the boys were overweight and ~7% were obese, whereas 4% were underweight. in comparison, 23% of girls were overweight, 12% were obese and 5% were underweight. anova indicated a significant difference in bmi iotf z-scores between boys and girls (p<0.05) as reported in detail elsewhere.[16] the normative gender-specific iotf cut-off criteria[11] were used to quantify obesity and overweight rates among participants. these values represent cut-off points chosen as percentiles that match adult cut-offs for bmi values. based on a child’s current bmi and age, their bmi at age 18 years can be predicted. the reference criteria used to categorise the sample population of children is set out in table 4. the average daily energy expenditure of the participants was 881.6 mets. the range was large, as indicated by an sd of 471.6 mets. the relationship between bmi iotf z-score categories and daily met energy expenditure for 7 10-year olds is presented in table 5. the highest energy expenditure and prevalence of overweight (25%) for table 1. iotf bmi criteria[11] grade bmi range at 18 years z-score thinness grade 3 <16 –3 thinness grade 2 16 <17 –2 thinness grade 1 17 <18.5 –1 normal weight 18.5 <25 0 overweight 25 <30 1 obesity ≥30 2 iotf = international obesity task force; bmi = body mass index. table 2. description of participants boys, n girls, n total, n age (years) 7 90 84 174 8 81 86 167 9 109 89 198 10 92 82 174 all groups 372 341 713 ethnicity 713 white 449 black 125 mixed race 91 asian 48 home language 709* english 547 afrikaans 54 isixhosa 108 *missing data for four participants. sajsm vol. 26 no. 4 2014 117 the age groups was found in the 10-year-olds. seven-year-olds expended the least energy and were the least active of all. although 8-yearolds showed the highest obesity incidence, they obtained relatively high met energy expenditures. one-way anova showed no significant relationship between daily physical activity levels and bmi categories for gender for any of the age groups. discussion declining levels of physical activity and subsequent increased sedentariness seem to have become normative lifestyles for many sa children. evidence of physical inactivity in children was found in the follow-up sa national risk behaviour survey, which found that 42% of children had insufficient daily physical activity levels.[5] a study done on a smaller scale reported that only 27% of a total of 30 children met the daily standardised requirements.[12] children of optimal bmi performed the most physical activity daily in the current study. th is fi nding that physical activity is a meaningful contributor to healthy living and weight a with what has been reported in the literature.[3] although pre-obesity was found to be most prevalent in 10-year-olds, they performed the most physical activity daily. th is supports an sa study that found that overweight children do accumulate the required level of daily physical activity. [17] bmi does not account for the increased lean muscle mass associated with growth and physical development in children and could have influenced the overestimation of pre-obesity. th e current study found that 8-year-olds were the most obese, but had relatively high daily energy expenditure. it is informative to realise that obesity is more prevalent among younger children, despite their being physically active. th is contrasts with a study[18] that found insuffi cient levels of physical activity in 7-year-old obese children due to bodily discomfort and a lack of motor skills and self-confidence. it is difficult to identify causal pathways, as factors contributing to obesogenic behav iour in children are complex and interrelated. although this study explored the association of bmi and physical activity as a single aetiological variable, the question is whether overweight and obese children should exceed the standard physical activity recommendation to derive similar benefi ts as their normal-weight counterparts, and whether to argue for weight management similar to adult guidelines. in accordance with the literature, children in the thinness grade 2 category were the least active of all participants, and their insuffi cient physical 0 10 7 8 9 10 20 30 40 50 60 70 80 age (years) pe rc en ta g e (% ) thinness grade 3 thinness grade 2 normal overweight obese thinness grade 1 fig. 1. bmi iotf z-scores and classifi cation of total group according to age. (bmi = body mass index; iotf = international obesity task force.) table 3. descriptive data for bmi and met level of total group variable n mean (sd) bmi (kg/m2) total 713 18.4 (3.2) boys 372 18.0 (2.8) girls 341 18.7 (3.6) bmi (iotf z-score) total 713 0.4 (0.7) boys 372 0.3 (0.7) girls 341 0.4 (0.8) age (years) 713 9.0 (1.1) daily met expenditure 713 881.6 (471.6) bmi = body mass index; met = metabolic equivalent of task; sd = standard deviation; iotf = international obesity task force. table 4. bmi criteria (iotf z-scores) and classifi cation of total group grade bmi range at 18 years z-score n (%) th inness grade 3 <16 –3 1 (0.1) th inness grade 2 16 <17 –2 5 (0.7) th inness grade 1 17 <18.5 –1 24 (3.4) normal weight 18.5 <25 0 464 (65.1) overweight 25 <30 1 149 (20.9) obesity ≥30 2 70 (9.8) all groups 713 (100) bmi = body mass index; iotf = international obesity task force. 118 sajsm vol. 26 no. 4 2014 activity has been ascribed to being sedentary for an average of 4 h per weekday and 6 8 h per day at weekends.[19] the results demonstrated that physical activity and bmi for young urban children from economically privileged primary schools is not significantly related and is in alignment with inconclusive evidence found in the literature.[2] although this study provides valuable information pertaining to the above, certain limitations existed that are inherent to the use of self-administered questionnaires. thus, challenges arose in the measurement of daily physical activity. furthermore, quantification of physical activity by using different instruments, varying from self-report questionnaires and pedometers to accelerometers, impedes comparative studies.[12] most of the relevant studies on children do not differentiate clearly between physical activity, exercise and sport, therefore complicating variables when contrasting evidence. applicability of the results to the broader urban population of young quintile 5 primary-school children in sa should be approached with caution, as the response rate of the principals was low. conclusion childhood overweight and obesity prevalence and lack of physical activity in 7 10-year-olds in financially privileged primary schools in a city in the eastern cape are relatively high. children of optimal weight performed the most daily physical activity. the incidence of pre-obesity is more prevalent in 8-year-olds than in 10-year-olds. when bmi is coupled with energy expenditure, the 8-year-olds engaged in aboveaverage levels of physical activity for the total group. although preobesity was the highest in 10-year-olds, they were the most active on a daily basis. underweight occurrence was extremely low, and children in the low bmi category were the least active of all participants. results did not reveal a significant relationship between daily level of physical activity when expressed as met energy expenditure and bmi. recommendations for future research overall, conflicting results emerged from evidence on the association between bmi and level of physical activity in young urban children from financially advantaged primary schools. the current study did not reveal a relationship between bmi and daily levels of physical activity. the establishment of a universally accepted set of classification criteria and cut-off points for defining overweight and obesity in children needs further exploration. although an internationally accepted valid and reliable paq for south africans was used to assess energy expenditure, more rigorous measures of daily physical activity through actigraphy should be used in future studies. acknowledgement. financial assistance was received from the national research foundation (nrf) and the nmmu as a research grant. references 1. wang y. diet, physical activity, childhood obesity and risk of cardiovascular disease. international congress series 2004;1262:176-179. [http://dx.doi.org/ 10.1016/j. ics.2003.12.018] 2. ortlieb s, schneider g, koletzko s, et al. physical activity and its correlates in children: a cross-sectional study (the giniplus and lisaplus studies). bmc public health 2013;13:349. [http://dx.doi.org/10.1186/1471-2458-13-349] 3. strong wb, malina rm, blimkie cj, et al. evidence based physical activity for schoolage youth. j pediatr 2005;146(6):732-737. [http://dx.doi.org/10.1016/j.jpeds.2005.01.055] 4. lambert ev. physical activity as a global risk factor for non-communicable diseases: time for action, what, why, when, who and how? s afr j sm 2012;24(1):25-26. 5. reddy sp, resnicow k, james s, et al. underweight, overweight and obesity among south african adolescents: results of the 2002 national youth risk behaviour survey. public health nutr 2008;12(2):203-207.[http://dx.doi.org/ 10.1017/ s1368980008002656] 6. rossouw h, grant c, viljoen m. overweight and obesity in children and adolescents: the south african problem. s afr j sci 2012;108(5/6):art.#907. [http://dx.doi.org/10.4102/ sajs.v108i5/6.907] 7. the national institute of child health and human development. study of early child care and youth development network. arch pediatr adolesc med 2003;157(1):185190. 8. armstrong m, lambert e, lambert m. physical fitness of south african primary school children, 6 to 13 years of age: discovery vitality health of the nation study. percept mot skills 2011;113(3):999-1016. [http://dx.doi.org/ 10.2466/06.10.13.pms.113.6.999-1016] 9. kruger r, kruger h, macintyre u. the determinants of overweight and obesity among 10-to15-year-old schoolchildren in the north west province, south africa – the thusa bana study. public health nutr 2006;9(3):351-358. [http://dx.doi.org/10.1079/phn2006849] 10. carter r, lubinsky j, domholdt e. rehabilitation research: principles and applications. 4th ed. usa: elsevier saunders, 2011:56-58. 11. cole t, flegal k, nicholls d, jackson a. body mass index cut offs to define thinness in children and adolescents: international survey. bmj 2007;335(2):194-197. [http:// dx.doi.org/10.1136/bmj.39238.399444.55] 12. mcveigh j, norris s. criterion validity and test-retest reliability of a physical activity questionnaire in south african primary school-aged children. s afr j sm 2012;24(2):43-48. 13. ainsworth b, haskell w, herrmann s, et al. 2011 compendium of physical activities: a second update of codes and met values. med sci sport exerc 2011;43(8):1575-1581. 14. american college of sports medicine. acsms guidelines for exercise testing and prescription. 8th ed. london: lippincott, williams and wilkins, 2010. 15. statsoft. statistica for windows. 8th ed. usa: statsoft, 2008. 16. mckersie j, baard ml. obesity in seven-to-ten-year-old children in urban primary schools in port elizabeth. s afr j sm 2014;26(2):55-58. [http://dx.doi.org/10.7196/sajsm.526] 17. reddy s, panday s, swart, d, et al. umthenthe uhlaba usamila – the south african youth risk behaviour survey, 2008. cape town: south african medical research council, 2010. 18. truter l, pienaar ae, du toit d. relationships between overweight, obesity and physical fitness of nine-to-twelve-year-old south african children. s afr fam pract 2010:52(3):227-233. [http://dx.doi.org/10.1080/20786204.2010.10873979] 19. puckree t, naidoo p, pillay p, naidoo, t. underweight and overweight in primary school children in ethekwini district in kwazulu-natal, south africa. afr j prim health care fam med 2011;3(1):art. 203. [http://dx.doi.org/10.10.4102.phcfm.v3i1.203] table 5. iotf bmi z-scores and daily met expenditure age (years)  thinness grade 2 thinness grade 1 normal overweight obese all groups n mean (sd) n mean (sd) n mean (sd) n mean (sd) n mean (sd) n mean (sd) 7 -  3 795 (494.9) 121 831 (474.8) 35 760 (335.1) 15 665 (254.7) 174 802 (434.9) 8 2 595 (120.9) 8 979 (533.9) 105 870 (562.6) 31 839 (368.3) 21 1 129 (820.2) 167 899 (570.3) 9 1 507 (0) 7 521 (141.9) 129 910 (432.0) 40 799 (344.3) 21 825 (438.1) 198 863 (414.8) 10 2 1 035 (159.8) 6 872 (648.3) 109 963 (437.1) 43 1 000 (409.2) 13 782 (373.6) 173 956 (431.4) iotf = international obesity task force; bmi = body mass index; met = metabolic equivalent of task; sd = standard deviation. sajsm 595 (commentarty).indd commentary 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license swimming during covid-19: operational recommendations and considerations for south african swimming venues l hill, 1, 2 bsc (med)(hons); p t nikolaidis,3 phd; b knechtle, 4,5 md 1 department of exercise science and sports medicine, university of cape town, cape town, south africa 2 division of gastroenterology and nutrition, department of paediatrics, mcmaster university, hamilton, canada 3 school of health and caring sciences, university of west attica, athens, greece 4 institute of primary care, university of zurich, zurich, switzerland 5 medbase st. gallen am vadianplatz, st. gallen, switzerland corresponding author: l hill (hlllee004@myuct.ac.za) the emergence of the novel coronavirus disease 2019 (covid-19) has resulted in restrictive measures, such as generalised lockdown and mandatory quarantine across the world.[1] in response, the government of south africa imposed one of the strictest lockdown measures in order to contain and control the spread of the virus.[2,3] fitness centres, gyms, swimming pools other exercise venues were forced to close as part of the lockdown. [2,4] infectious disease and public health specialists noted that all exercise venues were regarded as extremely high risk for the spreading of the virus. [5]however, as lockdown and several other restrictions began to ease, it is important understand the specific public health issues and preventative measures required to operate and manage swimming facilities.[6] it is still unclear whether possible contamination and transmission of covid-19 can occur in swimming pools due to limited knowledge and the unpredictable behaviour of the virus.[6] swimming is one of the most popular recreational activities in south africa[7] and access to swimming pools, both indoors and outdoors, offers an extraordinary opportunity for the prevention of sedentary and lifestyle-related diseases that may have been induced by the extended lockdown. [5,6] as such, access to safe swimming spaces has an important role to play in facilitating various activities, including adapted physical activity for people of all ages, abilities and socioeconomic backgrounds. [8] the safe reopening of swimming facilities during lockdown and their appropriate management requires the implementation of policies and guidelines to ensure the well-being of the public.[6] the current understanding of covid-19 is continually advancing as research around its prevention and treatment proceeds.[9] however, based on what is already known and working within the current public health guidelines, it is possible to define a framework of risks and outline potential preventive measures for sport. it is important to note that while covid-19 is exceptionally contagious in most enclosed environments, this might not be the case in swimming pools. [10] according to epidemiological data presently available, there have been no reported cases of covid19 from swimming pools or through the use of water. [11] as swimming is such a popular sport, prevention of covid-19 transmission in swimming pools must be examined. although these environments may present a lesser risk of infection that others, caution is still necessary regarding the operation within public health recommendations and guidelines.[12] this includes respecting current regulations and recognising that the understanding of the virus may change rapidly. within this context, the government of south africa already has specific requirements for maintaining swimming facilities regarding hygiene, sanitation, disinfection and good practice. [13] recently, the south african sports medicine association (sasma) released a position statement for the resumption of sport within the country.[3] the statement outlines five guidelines regarded as a minimum to be incorporated into any post-covid-19 return-tosport strategy. these include 1) education, 2) preparing the environment, 3) risk stratification of the specific sport, 4) risk stratification for the participants, and 5) the practical implementation of mitigating measures of different sports.[3] further, swimming south africa has also drafted covid-19 compliance directives [14] which outline the guidelines and recommendations for the return to competitive swimming, training and learning to swim. with these in mind, the potential safety considerations for swimming facilities are as follows: 1. constant monitoring of the epidemiological status locally and countrywide. 2. defining specific risk assessment based on general guidelines for the prevention of covid-19. this includes the facility and building structure, the swimming pool area, as well as the changing rooms and service areas. this is the specific attention paid to the maximum occupancy for minimising transmission and hygiene protocols. 3. acquisition and availability of personal protective equipment for staff, users and guests. this includes adherence to the department of health guidelines [12], including physical distancing, mask mandates and access to soap and hand sanitisers. for persons at the facility who are suspected to have covid-19, a swimming is one of the most popular recreational activities in south africa. since the emergence of the coronavirus disease 2019 (covid-19), south africa imposed one of the strictest lockdown measures to contain and control the spread of the virus. these measures included the closure of gyms, fitness centres and swimming pools across the country. however, as the restrictions begin to ease, it is important to consider how swimming facilities can reopen whilst simultaneously ensuring appropriate measures are in place to reduce covid-19 infections. outlined are recommendations and considerations for swimming facilities in south africa. currently there is no evidence to suggest that covid-19 transmission to humans is possible through water, making swimming one of the safer options for physical activity indoors. however, participation is still not without risk and compliance with government mandates and public health officials take precedent over the recommendations outlined in this article. keywords: swim, pandemic, operations, guidelines, safety s afr j sports med 2020; 32:1-3. doi: 10.17159/2078-516x/2020/v32i1a8993 mailto:hlllee004@myuct.ac.za http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8993 https://orcid.org/0000-0003-2092-318x https://orcid.org/0000-0001-8030-7122 https://orcid.org/0000-0002-2412-9103 commentary sajsm vol. 32 no. 1 2020 2 dedicated isolation room must be made available to allow for further assessment. 4. preparation of a dedicated covid-19 prevention plan which can be used on a daily basis as well as under extraordinary circumstances, such as the management of emergencies. 5. individual facilities should create specific rules and guidelines in accordance with public health recommendations for the prevention of covid-19 transmission. these should be readily available and made visible to users in order to reinforce specific hygiene rules and interpersonal distancing measures. facilities should consider internal penalties for those who do not adhere to the specific rules or regulations. further, facilities should implement mandatory temperature screening and the keeping of visitor logs which include contact details (for contact tracing purposes in the event of potential exposure). 6. facilities should continually develop and appraise their preventative measures through dedicated surveillance and monitoring, in conjunction with staff training. 7. due to the communicable nature of covid-19, it is crucial that facilities determine appropriate measures for first aid and emergency interventions. key operational measures to ensure the safe function of swimming facilities should include those specifically outlined by the department of health [12] and other public health specialists. these measures (see below) are subject to change and largely dependent on the specific facility in question. 1. the organisation of effective access control to the facility, swimming pool area and change rooms for both staff, users, and visitors. although already in place at most facilities, there should effective screening of covid-19 symptoms prior to arrival at the venue and explicit prohibition of those who are likely to have covid-19 symptoms, are awaiting test results for the virus or have recently come into contact with anyone who has tested positive for the virus. 2. this can be done through a self-assessment toolkit. [12] a. common symptoms of covid-19 may include but are not limited to: i. fever ii. chills iii. new or worsening cough iv. shortness of breath v. sore throat vi. difficulty in swallowing vii. decreased or loss of taste or smell viii. unusual or long-lasting headache ix. digestive issues such as nausea/vomiting, diarrhoea, stomach pain x. muscle aches that are unusual or long-lasting xi. extreme tiredness xii. sluggishness or lack of appetite xiii. coordination and balance issues b. considerations if a person falls into specific at-risk groups: i. getting treatment that compromises (weakens) the immune system ii. having a condition that compromises (weakens) the immune system iii. having a chronic (long-lasting) health condition iv. regularly going to a hospital or healthcare facility for treatment c. being in close physical contact with someone who currently has covid-19 (closer than one metre away from the infected person or in contact for more than 15 min, or medium risk >one metre or less than 15 min contact) [15] in the previous 14 days. close physical contact with someone who currently has covid-19 means any of the following: i. being less than two metres away in the same room, workspace, or area ii. living in the same home iii. being in the same classroom 3. within the exercise facility and in the pool, there must be encouragement for interpersonal distancing. this can largely be achieved through scheduled reservations, work shifts, one-way routes, or other means to prevent crowding within shared spaces. in the pool, it is important to limit a single person to a single lane. if not currently present, lane lines should be implemented with sufficient distance between them to maintain interpersonal separation. 4. facilities should strive to assure mandated water quality levels through appropriate disinfection and hygiene requirements. procedures should outline clear minimal requirements, including optimal residual disinfection activity and ph levels. water management should be addressed through local and country-specific by-laws. facilities should have in place effective and up-to-date water safety plans. 5. as covid-19 is currently known to be transmitted through the air, indoor facilities should ensure adequate air quality and microclimates aiming for maximum safety. it is not sufficient to only adhere to the minimum required levels. facilities should consider the best possible methods for achieving air exchange, internal circulation, and ventilation. 6. as recommended by public health officials, facilities should establish routine and appropriate protocols to ensure the sanitation of common areas, changing rooms and the pool area. sanitation should be done on a frequent basis with greater attention paid to high touch areas such as door handles, handrails, and communal waiting areas. sanitation should be conducted within the already available guidelines. disinfection and cleaning protocols must be clearly defined and routinely conducted with periodic inspection to ensure correct execution and effectiveness. 7. facility staff, users, and visitors must acknowledge the assumption of risk when utilising the swimming pool. although the recommendations above may assist in the mitigation of transmission of covid-19, it is essential to understand that no activity is risk-free. therefore, a consent or waiver document should be in place prior to use of the swimming facility. the way forward although the above recommendations may assist with the mitigation of risk associated with a highly communicable infection like covid-19, these recommendations should be commentary 3 sajsm vol. 32 no. 1 2020 considered as an addition to compliance to government and public health mandates. appropriate adherence to the recommendations and bylaws should support efforts to reduce possible viral outbreaks, whilst simultaneously giving the public access to physical activity venues. [5,6] whilst caution is still encouraged, the italian istituto superiore di sanità (national health institute) recently stated that there is no evidence that covid-19 can be spread to humans through the use of swimming pools or whirlpools [6], further supported by the centres for disease control and prevention (cdc). [11] if disinfection with chlorine is done correctly, in conjunction with adequate maintenance, the severe acute respiratory syndrome coronavirus 2 (sars-cov-2) can be inactivated, reducing its infectivity and transmission. [10] previously, sarscov-1 was completely inactivated in wastewaters by chlorine (10 mg/l for 10 minutes with a concentration of free residual chlorine of 0.5 mg/l or with chlorine dioxide 40 mg/l for 30 minutes with a residual free chlorine concentration of 2 .19 mg/l).[10] therefore, swimming may be one of the safer exercise activities the public can undertake as long as strict protocols are observed. nevertheless, independently from whether covid-19 is transmissible or not in water, the recommendations should follow the general guidelines outlined by national and international public health agencies. a swimming pool is not only the water, but also a venue where people aggregate and are in close contact with each other both before and after swimming. moreover, it is important to note that other risks are involved when travelling to facilities i.e. public transportation, which may also increase risk of covid-19 exposure. it is necessary therefore to highlight the guidelines for swimming and pool venues should be done should be done within the context of the general guidelines of resumption of sport in south africa.[3] conclusion finally, the recommendations and considerations outlined within this commentary should assist owners and operators with reopening various facilities around the country. it is suggested that facilities employ a dedicated compliance officer whose sole task is the monitoring, evaluating, and organising the various preventative measures and their implementation. disclaimer this document has been compiled as a guide for the safe return to swimming and should be used only as a guideline and within the greater context of national and international recommendations. it is still the responsibility of organisers, operators, and administrative staff to ensure that facilities for swimming and training are compliant with directives by the who, nicd and doh, and updates should be adhered to in a timeous manner. this document is not a tool to return to sport prematurely but should be used aligned with the statutory guidelines (which may change constantly and differ from area to area). conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: lh conceptualised, designed, drafted, and prepared the above manuscript. ptn and bk critically revised and contributed to the manuscript. references 1. lancet. covid-19: too little, too late? lancet 2020 ;395(10226):755. [doi: 10.1016/s0140=6736(20)30522-5][pmid: 32145772] 2. dyer o. covid-19: africa records over 10 000 cases as lockdowns take hold. bmj 2020;369: m1439. [doi: 10.1136/bmj.m1439][pmid: 32269023] 3. ramagole d, janse van rensburg dc, pillay l, et al. implications of covid-19 for resumption of sport in south africa: a south african sports medicine association (sasma) position statement. sa j sports med 2020;32(1):1–6. [doi: 10.17159/2078-516x/2020/v32i1a8484] 4. carmody s, murray a, borodina m, et al. when can professional sport recommence safely during the covid-19 pandemic? risk assessment and factors to consider. br j sports med 2020;54(16):946–948. [doi: 10.1136/bjsports-2020-102539] [pmid: 32381501] 5. ding d, del pozo cruz b, green ma, et al. is the covid-19 lockdown nudging people to be more active: a big data analysis. br j sports med 2020;54(20):2019–2020. [doi: 10.1136/bjsports-2020-102575] 6. romano spica v, gallè f, baldelli g, et al. swimming pool safety and prevention at the time of covid-19: a consensus document from gsms-siti. ann ig. 2020;32(5):439–448. [doi: 10.7416/ai.2020.2368] [pmid: 32578839] 7. hill l, grand’maison v. swimming, south africa and the olympics: a history of women’s participation. in: olympika: the international journal of olympic studies 2017;26:36–52. available: http: library .oluympic.org 8. chase nl, sui x, blair sn. comparison of the health aspects of swimming with other types of physical activity and sedentary lifestyle habits. int j aquatic res educ 2008;2(2), article 7. [doi: 10.25035/ijare.02.02.07] 9. yang y, xiao z, ye k, et al. sars-cov-2: characteristics and current advances in research. virol j 2020;17: 117. [doi:10.1186/s12985-020-01369-z] 10. la rosa g, bonadonna l, lucentini l, et al. coronavirus in water environments: occurrence, persistence and concentration methods a scoping review. water res 2020;179:115899. [doi:10.1016/j.watres.2020.115899] [pmid: 32361598] 11. centers for disease control and prevention. considerations for public pools, hot tubs, and water playgrounds during covid-19. 2020: cdc 24/7 12. south africa. department of health. corona virus(covid-19) pandemic 2020 [cited 2020 oct 7]. available from: http://www.health.gov.za/index.php/outbreaks/145-coronavirus-outbreak/465-corona-virus-outbreak 13. south africa. occupational health and safety act government gazette 1993; 337 no.14918 [cited 2020 oct 7]. available from: https://www.gov.za/documents/occupational-health-andsafety-act 14. swimming south africa. ssa directive: ensuring a safe aquatic environment and protecting the health of members 2020; ssa covid-19 directive 01 9 june 2020 [cited 2020 oct 9]. available from: http://swimsa.org/about/correspondence/ general-news/directive/view 15. mann rh, clift bc, boykoff j, et al. athletes as community; athletes in community: covid-19, sporting mega-events and athlete health protection. br j sports med 2020;54(18):1071– 1072. [doi:10.1136/bjsports-2020-102433][pmid: 32303522] sajsm 555.indd original research sajsm vol. 26 no. 4 2014 119 background. non-traumatic bicycle injuries are common. however, research available on non-traumatic injuries in amateur cyclists is more than a decade old, and most of the research on this topic has been done in europe and america on professional cyclists in multi-day cycling events. an understanding of the common injuries may lead to appropriate prevention intervention. objective. to determine the incidence of overuse injuries in amateur cyclists preparing for participation in a 1-day cycle challenge. methods. a questionnaire was emailed to participants of the 2012 momentum 94.7 cycle challenge, which amateur participants ≥18 years old were invited to complete. data on demographics, training habits and the participants’ injury profile in the preceding year were collected. results. of the 3 300 respondents, 75% were male and 59% were between 30 and 50 years old. non-traumatic injury, pain or neurological symptoms were reported by 88% of the respondents. the percentages of all respondents who experienced problems in the following anatomical areas were as follows: neck 34%, back 41%, hand/wrist 41%, buttock/perineum 41%, hip 7%, knee 33% and foot/ankle 24%. knee pain was responsible for the need to stop training for the largest percentage of respondents. neurological complaints were common in respondents who experienced neck, back, hand/wrist, buttock/perineum and foot/ankle problems. conclusion. non-traumatic injuries in amateur cyclists are common, with back, hand/wrist and buttock/perineal symptoms the most frequent problems. knee problems caused the greatest need to stop training and seek medical help. s afr j sm 2014;26(4):119-122. doi:10.7196/sajsm.555 non-traumatic injury profile of amateur cyclists a van der walt,1 mb chb; d c janse van rensburg,1 md; l fletcher,2 phd; c c grant,1 phd; a j van der walt,3 fcp (sa) 1 section sports medicine, university of pretoria, south africa 2 department of statistics, university of pretoria, south africa 3 department of internal medicine, university of the witwatersrand, johannesburg, south africa corresponding author: a van der walt (altavanderwalt@me.com) cycling is a popular sport, in which a large number of amateurs now participate in 1-day events. the prevalence of non-traumatic bicycle injuries can be as high as 87%.[1,2] the most common injury sites are the knee, neck/shoulder, back, hand/wrist and buttock/ perineum.[1-10] in professional road cyclists, lower back pain and anterior knee pain are the most prevalent overuse injuries, and knee pain is the most likely cause of time lost.[3] ulnar and median nerve compression appears to be the most common problem in the upper limb.[4-6] one study reported this as an uncommon problem, whereas another study noted that 70% of cyclists experience either motor or sensory symptoms, or both.[3,4] neck and shoulder symptoms are common.[1,2] in a study carried out on a 500-mile, 8-day bicycle tour, 66.4% of the cyclists reported some neck or shoulder symptoms, while significant symptoms were reported by 20.4%.[7] perineal pain, numbness and erectile dysfunction are complications of prolonged saddle pressure.[11] twenty-two per cent of male cyclists reported symptoms arising from the innervation area of the pudendal nerve, and impotence was reported by 13%.[8] much of the current knowledge on overuse cycling injuries comes from cyclists involved in cycle tours ≥5 days, or from professional cyclists attending training camps.[3,4,7,8] research available on the profile of non-traumatic injuries in amateur cyclists is >10 years old. [2,7] south africa hosts two of the world’s largest 1-day cycle challenges, in which most participants are amateurs. knowledge of the nontraumatic injury profile in these participants is relevant in order to develop appropriate prevention intervention. the objective of this study was to determine the incidence of overuse injuries in amateur cyclists preparing for a 1-day cycle challenge. this article describes only the injury profile of the cyclists. methods the momentum 94.7 cycle challenge is a 94.7-km cycle race that takes place in johannesburg. in 2012, 26 331 people entered the event, the vast majority being amateur cyclists. an e-mail was sent out by the momentum 94.7 cycle challenge race organisers 10 days before the 2012 event, explaining the objective of the study and asking all amateur cyclists ≥18 years to complete a questionnaire via a web link. the questionnaire was voluntary and anonymous; participants had the option to start and then quit the questionnaire at any time. only questionnaires completed between the time that the e-mail was sent out and the race day were used. the retrospective questionnaire comprised three parts. the demographic part included general information about the participants that could have affected training and influenced the cyclists’ injury profile. the second part focused on training habits. the final part enquired about non-traumatic injuries sustained (including all musculoskeletal and all neurological concerns participants may have experienced due to cycling in the preceding year), and treatment received and time lost. concerns directly related to falls or accidents were not included. questions design was based on data from the literature regarding cycling injuries. the protocol for this study was approved by both the master of medicine (mmed) committee and the ethics committee at the faculty of health sciences of the university of pretoria. data analysis comprised frequency tables and cross-tabulations to summarise, and χ2 tests were used to evaluate associations. results of the 26 331 cyclists who entered the momentum 94.7 cycle chall enge, 14% (n=3 666) followed the link to the survey and 13% 120 sajsm vol. 26 no. 4 2014 (n=3 300) completed the questionnaire. of the respondents, 75% (n=2 476) were male and 59% (n=1 942) were between 30 and 50 years old (fig. 1). th ese percentages correlated with the general demographics of all participants entering the race. non-traumatic injury, pain or neurological symptoms were reported by 88% (n=2 904) of the respondents. problems reported included the neck (34%, n=1 109), back (41%, n=1 340), hand/wrist (41%, n=1 355), buttock/perineum (41%, n=1 358), hip (7%, n=234), knee (33%, n=1 078) and foot/ankle (24%, n=782). signifi cant association was found between sex and injury incidence (χ2=8.51; df=1; p=0.004). a negative standardised residual (–2.4) indicated that females are more prone to injuries than males, especially of the neck, knee and foot/ankle (fig. 2). no signifi cant association between age and injury susceptibility was found (χ2=8.25; df=5; p=0.14). however, the standardised residual (2.3) of respondents >60 years showed that substantially more were observed in the no-injury category than expected. also, no associations were found between age and any specifi c injuries or combinations of injuries (χ2=663.48; df=610; p= 0.07) (fig. 3). complaint seriousness was assess ed by the percentage of participants who needed to stop training, consult a physiotherapist and/or doctor and/or require surgery (table 1). knee pain was responsible for the largest percentage (17%) of respondents who needed to stop training. few respondents sought help from a doctor and/or physiotherapist. more respondents sought help from a physiotherapist than from a doctor. four per cent of respondents with knee problems required surgery, while <1% of respondents who experienced problems in other anatomical areas needed surgery. forty-nine per cent (n=540) of the 1 109 respon dents who experienced neck pain also exper ien ced neurological symptoms, e.g. numb ness or pins and needles in the hands and arms. in 39% (n=211) of these, the neurological symptoms disappeared immediately aft er cycling. in a further 37% (n=202) they disappeared within 1 h aft er cycling, while 5% (n=25) experienced the symptoms for >1 week aft er cycling. twenty per cent (n=261) of the 1 340 respondents who experienced back pain experienced neurological symptoms, e.g. pins and needles or numbness in their legs. in 34% (n=88) of these, symptoms disappeared immediately aft er cycling. in a further 35% (n=91), the symptoms lasted <1 h aft er cycling, while in 10% (n=26), these symptoms lasted for >1 week. wrist symptoms were reported by 41% (n=1 355) of respondents. of these, 23% (n=307) had pain, 67% (n=909) had pins and needles, 44% (n=595) had loss of sensation and 13% (n=176) had weakness. some respondents had more than one symptom. in 85% female male 21 29 pe rc en ta g e (% ) 0 5 10 15 20 25 18 20 30 39 40 49 50 59 >60 age (years) fig. 1. age and sex distribution of respondents. 50 45 40 pe rc en ta g e (% ) female male 35 30 25 20 15 10 5 0 n b h/w b/p h k f/a injury site fig. 2. percentage of all male v. female respondents that reported pain or other symptoms in the diff erent anatomical areas. (n = neck; b = back; h/w = hand/wrist; b/p = buttock/perineum; h = hip; k = knee; f/a = foot/ankle.) 70 60 50 40 30 20 10 0 18 20 21 29 30 39 40 49 50 59 older than 60 pe rc en ta g e (% ) n b h/w b/p h k f/a injury site fig. 3. percentage of respondents in the different age groups that experienced pain or other symptoms in the diff erent anatomical areas. (n = neck; b = back; h/w = hand/wrist; b/p = buttock/perineum; h = hip; k = knee; f/a = foot/ankle.) sajsm vol. 26 no. 4 2014 121 (n=1 155), these symptoms disappeared within 1 h after cycling. symptoms were experienced in both hands by 64% (n=867) of respondents with wrist concerns, and in 20% (n=271) only in the left hand and 16% (n=217) only in the right hand. of the 1 358 respondents who complained of symptoms in the buttock/perineal area, 53% (n=724) had pain, 49% (n=649) had loss of sensation, 25% (n=339) had pins and needles and 3% (n=40) experienced erectile dysfunction. some experienced more than one symptom. in 70% (n=947), these symp toms disappeared within 1 h of cycling. how ever, erectile dysfunction is a notable exception. only 0.02% (n=40) of males experienced erectile dysfunction, but in 20% (n=8) of these, the problem endured for >1 week. although only 7% (n=234) of respondents experienced hip pain, the symptoms lasted longer than for other injuries. in 18% (n=43), the symptoms lasted >1 week, while another 19% (n=44) had pain for >1 day but <1 week, and 20% (n=46) had pain for >1 h but <1 day. thus, 57% (n=133) had pain enduring for >1 h. knee problems were reported by 33% (n=1 078). of these, 56% (n=600) experienced pain in the anterior area of the knee, 37% (n=398) on the lateral side, 18% (n=179) medially and 6% (n=67) posteriorly. on the questionnaire, respondents could choose more than one anatomical area to indicate where problems were experienced. knee pain lasted >1 week in 14% (n=85) of respondents with anterior knee pain, 19% (n=73) with lateral knee pain, 19% (n=37) with medial knee pain and 15% (n=10) with posterior knee pain. foot and ankle problems were noted by 24% (n=782). of these, 60% (n=469) reported numbness of the foot, 47% (n=366) pins and needles of the foot, 20% (n=155) pain in the foot, 9% (n=68) pain in the ankle, and only 3% (n=23) weakness of the foot. some respondents experienced more than one symptom. in 45% (n=489), the symptoms disappeared immediately after cycling, and in a further 35% (n=381), it disappeared within 1 h after cycling. discussion eighty-eight per cent (n=2 904) of respondents complained of a non-traumatic injury, pain or neurological symptoms. this finding agrees with data that found that non-traumatic injuries in cyclists can be as high as 87%.[1,2] however, not all pain or other symptoms in this study were necessarily related to a nontraumatic cycling injury. an individual history and clinical examination were not carried out. respondents were asked only whether they experienced pain or other symptoms not due to trauma. back pain, hand/wrist problems (pain, numbness or weakness) and buttock/perineal pain or numbness were the most common problems cyclists experienced (41% each). many respondents also experienced neck pain (34%) and knee pain (33%). foot/ankle problems were less common (24%). only 7% experienced hip problems. wilber et al.[2] also made use of a questionnaire to assess overuse injuries in amateur cyclists, and found neck injuries/ complaints to be the most common (49%), followed by knees (42%), groin/buttock (36%), hands (31%) and back (30%). bicycles, cycling gear and emphasis on bike setup have developed since the publication of wilber et al.’s study in 1995, which may account for some of the differences in the results between wilber et al.’s study and the current study. a review article on non-traumatic bicycle injuries found the prevalence of injuries to the knee to be 22 64%, neck 3 49%, hand/wrist 10 70%, buttocks/ perineum 9 61%, back 15 50%, upper leg/hip 2 25%, and lower leg/foot 7 22%.[3] although most of these studies were done on multi-day cycle events, our data fit well with these findings. in evaluating the seriousness of the problem in terms of the need to stop training, knee injuries appeared to be the most serious, with 17% of respondents with knee problems needing to stop training. this finding correlates with research done on professional road cyclists.[3] after knee injuries, in order of decreasing frequency, the need to stop training was highest in hip-related problems (13%), back-related problems (9%), neckrelated problems (5%), foot/ankle-related problems (4%), hand/wrist-related problems (2%) and finally buttock/perineum-related problems (1%). even though buttock/perineal problems had a high incidence (41%) very few needed to stop training. weiss[7] reported knee and neck/shoulder problems the most common areas with symptoms severe enough to stop cycling. hip and knee injuries accounted for the most doctor visits, whereas neck and back injuries had the highest percentage of physiotherapy consultations. knee injuries were responsible for the largest number of cyclists receiving medical treatment in weiss’s study.[7] four per cent of respondents with knee pain required surgery. in all the other anatomical areas, <1% of the respondents who experienced pain needed surgery. no study could be found for comparison with the current study. an association was found between sex and the probability of sustaining an injury in general (p=0.004). however, this association could have been influenced by the large sample size. in the current study, females were more prone to injuries than males. the specific injury profiles showed that females are more inclined to suffer neck, knee and foot/ankle injuries. although wilber et al.[2] found no significant difference between male and female injuries in the various anatomical sites, they reported that female cyclists complained 1.5 times more than male cyclists about neck problems. table 1. respondents’ problems and treatment sought area needed to stop training, n (%) sought help from a doctor and a physiotherapist, n (%) sought help from a doctor, n (%) sought help from a physiotherapist, n (%) needed surgery, n (%) neck 53 (5) 83 (8) 121 (11) 251 (23) 3 (0.3) back 121 (9) 94 (7) 160 (12) 297 (22) 6 (0.4) hand/wrist 24 (2) 18 (1) 50 (4) 47 (4) 5 (0.4) buttock/perineum 43 (1) 6 (0.2) 37 (1) 29 (1) 6 (0.2) hip 31 (13) 22 (9) 39 (17) 50 (21) 1 (0.4) knee 178 (17) 108 (10) 185 (17) 222 (21) 40 (4) foot/ankle 30 (4) 21 (3) 62 (8) 37 (5) 2 (0.3) 122 sajsm vol. 26 no. 4 2014 no statistical association between age and injuries was found. it is, however, noticeable that the 18 20-year age group had a proportionally higher incidence of buttock/perineal, hip and knee problems than other age groups (fig. 3). less than 1% (n=31) of the respondents belonged to this age group; for this reason, this finding is of doubtful significance. no other studies could be found that compared age and cycling injuries. it is interesting that fewer than expected respondents in the ≥60 years age group sustained any injuries. this could possibly be attributed to years of cycling experience, since 55% of this age group had been participating in events for >10 years and a further 24% had been participating in events for 5 10 years. neurological symptoms were common. thirty-seven per cent (n=1 241) of respondents reported neurological symptoms in the wrists and hands. this finding correlates well with wilber et al.’s[2] study, which reported hand symptoms in 31% of recreational cyclists. patterson et al.[4] found neurological symptoms in 70% of cyclists who participated in a 600-km ride. however, participants taking part in a 600-km ride would cycle more kilometres when training than the average amateur cyclist training for a 100-km cycle challenge, which may account for the difference in percentages. nerve conduction studies on cyclists before and after a 6-day bicycle tour found that long-distance cycling may promote physiological changes in the deep branch of the ulnar nerve. long-distance cycling may also exacerbate symptoms of carpal tunnel syndrome.[12] the high prevalence of neurological hand symptoms found in our study indicates that ulnar and median nerve palsy are not only a problem among professional cyclists participating in multi-day cycle events, but are also found in amateur cyclists who participate in 1-day events. slane et al.[13] found that padded gloves and changing hand position can decrease the pressure applied to the ulnar and median nerves. eighty-four per cent (n=655) of respondents with foot/ankle problems had neurological symptoms such as pins and needles, weakness and loss of sensation. wanich et al.[10] reported that increased stiffness of cycling shoes may provide more efficient energy transfer but that it also increases forefoot pressure. of the 1 358 respondents with buttock/ perineal complaints, 62% (n=842) had neurological symptoms. these symptoms abated mostly within 1 h after cycling had stopped, except in the small percentage (0.02%) of males who experienced erectile dysfunction. leibovitch and mor[11] reviewed bicycling-related urogenital disorders and reported erectile dysfunction in 13 24% of cyclists, and urological complaints and nerve entrapment syndromes in 50 91%. our findings differ substantially; perhaps, as a result of underreporting of this sensitive subject in our study. the difference between our findings and those by leibovitch and mor might also be due to the fact that amateur cyclists training for a 1-day event spend a lot less time on a bicycle than professional cyclists and cyclists involved in multi-day events. a selection bias in the article by leibovitch and mor should also be considered, as the focus was on genito-urinary complaints in cyclists. forty-nine per cent (n=540) of the respondents with neck complaints and 20% (n=261) of the respondents who reported back pain also reported neurological symptoms in the arms and legs. manninen and kallinen[14] reported neurological symptoms in the legs associated with lower back pain in 32% of the 92 triathletes who reported lower back pain. no other studies investigating the relationship between neurological symptoms related to neck and back pain in cyclists could be found. this study was based on a retrospective questionnaire, which has the advantage of providing access to a large sample size. however, the study has certain limitations, such as recall bias and volunteer bias. in order to make specific diagnoses, clinical examinations and further investigations would be needed. conclusion non-traumatic injuries, pain not due to trauma and neurological symptoms are common in amateur cyclists training for a 1-day cycle challenge. back pain, hand/wrist symptoms and buttock/perineal pain or numbness were the most common problems cyclists experienced, followed by neck pain, knee pain, foot/ankle problems and, lastly, hip problems. knee pain appears to be the problem of most concern in amateur cyclists. compared with other anatomical areas, a disproportionate number of cyclists with knee problems needed to stop training, visit a doctor and require surgical intervention. neurological symptoms were experienced by a large percentage of respondents who experienced neck and back pain, hand/wrist symptoms and buttock/ perineal symptoms. very little current research is available on non-traumatic injuries in amateur cyclists. the objective of this study was not to identify specific cycling injuries but rather to determine the extent and seriousness of non-traumatic injuries, pain or neurological dysfunction in anatomical areas that are believed to be potential high-risk injury areas in cyclists. the information from this study can therefore be used as a foundation to guide future research to investigate the causes of non-traumatic injuries in cyclists, and may direct interventions that help with the prevention of non-traumatic injuries in cyclists. references 1. dettori nj, norvell dc. non-traumatic bicycle injuries: a review of the literature. sports med 2006;36(1):7-18. [http://dx.doi.org/10.2165/00007256-200636010-00002] 2. wilber ca, holland gj, madison re, loy sf. an epidemiological analysis of overuse injuries among recreational cyclists. int j sports med 1995;16(3):201-206. [http:// dx.doi.org/10.1055/s-2007-972992] 3. clarsen b, krosshaug t, bahr r. overuse injuries in professional road cyclists. am j sports med 2010;38(12):2494-2501. [http://dx.doi.org/10.1177/0363546510376816] 4. patterson jm, jaggars mm, boyer mi. ulnar and median nerve palsy in long-distance cyclists. am j sports med 2003;31(4):585-589. [http://dx.doi.org/10.1177/036354650 30310041801] 5. mellion mb. common cycling injuries: management and prevention. sports med 1991;11(1):52-70. [http://dx.doi.org/10.2165/00007256-199111010-00004] 6. dannenberg al, needle s, mullady d, kolodner kb. predictors of injury among 1 638 riders in a recreational long-distance bicycle tour: cycle across maryland. am j sports med 1996;24(6):747-753. [http://dx.doi.org/10.1177/036354659602400608] 7. weiss bd. non-traumatic injuries in amateur long distance bicyclists. am j sports med 1985;13(3):187-192. 8. anderson kv, bovim g. impotence and nerve entrapment in long distance amateur cyclists. acta neurol scand 1997;95(4):233-240. [http://dx.doi.org/10.1111/j.1600-0404.1997. tb00104.x] 9. cohen gc. cycling injuries. can fam physician 1993;39:628-632. 10. wanich t, hodgkins c, columbier ja, muraski e, kennedy jg. cycling injuries of the lower extremity. j am acad orthop surg 2007;15(12):748-756. 11. leibovitch i, mor y. review. the vicious cycling: bicycling related urogenital disorders. eur urol 2005;47(3):277-286. [http://dx.doi.org/10.1016/j.eururo.2004.10.024] 12. akuthota v, plastaras c, lindberg k, tobey j, press j, garvan c. the effect of long-distance bicycling on ulnar and median nerves: an electrophysiologic evaluation of cyclist palsy. am j sports med 2005;33(8):1224-1230. [http://dx.doi. org/10.1177/0363546505275131] 13. slane j, timmerman m, ploeg hl, thelen dg. the influence of glove and hand position on pressure over the ulnar nerve during cycling. clin biomech (bristol, avon) 2011;26(6):642-648. [http://dx.doi.org/10.1016/j.clinbiomech.2011.03.003] 14. manninen jso, kallinen m. low back pain and other overuse injuries in a group of japanese triathletes. br j sports med 1996;30(2):134-139. [http://dx.doi.org/10.1136/bjsm.30.2.134] sajsm contents.indd the south african journal of sports medicine the editor the south african journal of sports medicine po box 115, newlands, 7725 tel: (021) 650-4558 fax: (021) 686-7530 e-mail: mike.lambert@uct.ac.za article submissions: www.sajsm.org.za the views expressed in individual articles and advertising material are the personal views of the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent of the publishers. plagiarism is defined as the use of another’s work, words or ideas without attribution or permission, and representation of them as one’s own original work. manuscripts containing plagiarism will not be considered for publication in the sajsm. for more information on our plagiarism policy, please visit http://www.sajsm.org.za/index.php/sajsm/about/editorialpolicies editor prof. mike lambert university of cape town editorial board dr kerith aginsky university of the witwatersrand dr theresa burgess university of cape town dr richard de villiers drs van wageningen and partners, somerset west dr lize havemann-nel north west university dr christa janse van rensburg university of pretoria dr louis holtzhausen university of the free state prof. frank marino charles sturt university, australia dr babette pluim royal netherlands lawn tennis association, the netherlands publisher health and medical publishing group 28 main road, rondebosch, 7700 private bag x1, pinelands, 7430 tel: (021) 681-7200 hmpg editor-in-chief janet seggie consulting editor jp de v van niekerk deputy editor bridget farham editorial systems manager melissa raemaekers scientific editor ingrid nye technical editors emma buchanan, paula van der bijl art director brent meder dtp/layout carl sampson production assistant bronlyne granger head of publishing robert arendse head of sales and marketing diane smith | tel: (012) 481-2069 repro & printing creda communications volume 26 | number 3 | october 2014 the south african journal of sports medicine contents editorial 67 healthy active kids south africa: how do we score? m lambert original research 69 radiological changes among artistic gymnasts in gauteng province a geldenhuys-koolen, d constantinou, y coopoo 73 comparison of the e�ect of semi-rigid ankle bracing on performance among injured v. non-injured adolescent female hockey players t j ellapen, n acampora, s dawson, j arling, c van niekerk, h j van heerden 77 steps that count: pedometer-measured physical activity, self reported physical activity and current physical guidelines – how do they relate? j d pillay, t l kolbe-alexander, k i proper, s a tomaz, w van mechelen, e v lambert 81 doping in sport: attitudes, beliefs and knowledge of competitive high school athletes in gauteng province k nolte, b j m steyn, p e krüger, l fletcher review 87 dietary supplements containing prohibited substances: a review (part 2) p van der bijl commentary 91 abrasion injuries on arti�cial turf: a real risk or not? d m twomey, l a petrass, p r fleming case report 93 a case of cyclist’s nodule in a female patient n z makhanya, m velleman, f e suleman 96 cpd questionnaire 1 | p a g e the south african rugby union: sa rugby injury and illness surveillance and prevention project (sariispp) youth week injury surveillance report 2018 2 | p a g e sa rugby injury and illness surveillance and prevention project (sariispp) youth week injury surveillance report 2018 prepared by: lindsay starling with assistance from: clint readhead, wayne viljoen, mike lambert citation: starling, l., readhead, c., viljoen, w. and lambert, m. (2019). the south african rugby union youth weeks injury surveillance report 2018. s afr j sports med 2019;31:1-19. doi: 10.17159/2078-516x/2019/v31i1a6365 definitions .............................................................................................. 3 summary ................................................................................................ 4 injury incidence ...................................................................................... 5 injury incidence trends ........................................................................... 8 u13 craven week ...................................................................................... 8 u16 grant khomo week ............................................................................ 8 u18 academy week................................................................................... 8 u18 craven week ...................................................................................... 8 injury event .......................................................................................... 10 body location ....................................................................................... 13 new vs recurrent ................................................................................. 13 game quarter ...................................................................................... 14 concussion ........................................................................................... 15 references ...................................................................................... 19 http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6365 http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6365 https://orcid.org/0000-0003-1275-6908 https://orcid.org/0000-0002-9432-6153 https://orcid.org/0000-0001-8979-1504 3 | p a g e definitions medical attention injury: the injury definitions were based on the consensus statement of 2007 for injury reporting in rugby union.1 all injuries that were seen by the tournament medical doctors were classified as medical attention injuries, which are defined by the statement as an “injury that results in a player receiving medical attention”.1 time-loss injury: medical attention injuries were further categorised as time-loss injuries, where appropriate, which are defined as “an injury that results in a player being unable to take a full part in future rugby training or match play”.1 injury rate: for this report, an injury rate is the number of injuries expressed per 1000 player exposure hours. this normalised version of the number of injuries facilitates comparison between the youth week tournaments in 2018, previous tournaments and to other international literature. moreover, the injury rate is expressed as a mean with 95% confidence intervals. a 95% confidence interval around a mean value indicates that there is a 95% chance (i.e. very high chance) that the true value falls within this range. in this report, we are using the approach of examining the overlap of the confidence intervals to determine whether the injury incidences are significantly different; if the range of confidence interval values of two comparisons do not overlap, there is a strong chance (95%) that their injury rates are different from each other. we have opted for this method because it is conservative and less likely to produce false positive results.2 new, subsequent and recurrent injuries: in 2018, the first injury a player sustained in the tournament, was defined as a ‘new injury’. any injury that the same player sustained after this initial injury was defined as a ‘subsequent injury´. a ‘recurrent injury’ was any subsequent injury of the same type and to the same site to that which a player had sustained previously. 4 | p a g e summary the boksmart national rugby safety programme has been exploring the injury rates and patterns at the various sa rugby youth weeks since 2011 as part of the sa rugby injury and illness surveillance and prevention project or sariispp. this dataset provides insight into the injury profile of players participating at the youth tournaments, and how the game is changing over time. it also helps to identify any areas of concern that might require further intervention by the governing body to make the game safer. this report focusses on the data from the 2018 boys’ tournaments [u13 craven week (cwu13), u16 grant khomo week (gku16), u18 academy week (awu18) and u18 craven week (cwu18)], but also makes comparisons to data collected annually since 2011. the injury data were recorded by the designated data capture researcher assigned to each medical facility at the youth week tournaments. in cases where more information became available about an injury after the tournament, the injury data were updated to reflect the most accurate information. for the 2018 youth week tournaments, the time-loss injury rates were similar across the tournaments, with the u18 academy week having a slightly higher injury rate than the other tournaments. when combining the injury rates of all tournaments from 2011 – 2018 the u18 craven week had the lowest injury rate of all tournaments. in 2018, injuries most frequently occurred to the ball carrier (i.e. the player being tackled), with the u16 grant khomo week recording the highest injury rates to both the ball carriers and tacklers of all the tournaments. concussions were the most frequent injury diagnosis recorded in 2018 and although not significant, there was a notable decrease in overall concussion incidence between 2017 and 2018. the concussion incidence increased at the u18 academy week and decreased at all the other tournaments. most new injuries were muscle injuries and the incidence of new injuries was significantly higher than recurrent injuries. 5 | p a g e injury incidence eighty-two teams competed in the 2018 youth week tournaments (cwu13 = 18 teams, gku16 = 18 teams, awu18 = 28 teams, cwu18 = 18 teams). there were 236 medical attention injuries during all the tournaments in 2018; thirty four percent of these (n = 81) were time-loss injuries. the combined tournaments’ injury incidence and 95% confidence intervals for all medical attention injuries was 57 injuries (50 to 65)/1000 player hours, and the injury incidence for time-loss injuries was 20 injuries (15 to 24)/1000 player hours. there were no significant differences in the incidence of medical attention or time-loss injuries across the tournaments in 2018 (table 1). table 1: number and incidence (95% ci)/1000 player hours of medical attention and time-loss injuries in the 2018 youth week tournaments. medical attention injuries time-loss injuries number incidence number incidence cwu13 68 76 (58 – 94) 19 21 (12 – 31) gku16 53 65 (48 – 83) 15 19 (9 – 28) awu18 67 46 (35 – 57) 32 22 (14 – 29) cwu18 48 51 (36 – 65) 15 16 (8 – 24) combined total 236 57 (50 – 65) 81 20 (15 – 24) there were also no significant differences in the number of medical attention or time-loss injuries per match across the tournaments. from a practical perspective this translates into each tournament requiring similarly scaled medical resources. more specifically, each tournament ideally requires one medical doctor available on-site, per every match played concurrently (table 2). in 2018 the tournament schedules were structured for the u18 academy week and u18 craven week tournaments to play at the same venue. matches were played concurrently. under these circumstances, two medical doctors are required for sufficient medical support. the u13 craven week and u16 grant khomo week tournaments were also played concurrently at the same venue. on days 1, 3 and 4 of the tournaments there were as many as four matches being played simultaneously, while on day 2 there were a maximum of two matches being played simultaneously. a minimum of one additional medical 6 | p a g e doctor therefore needs to be available on-site on days 1, 3 and 4 of these combined tournaments to provide sufficient medical cover. table 2: number of medical attention and time-loss injuries per match and per hour in the 2018 youth week tournaments. tournament number of matches match duration (mins) medical attention injuries/match time-loss injuries/match medical attention injuries/hour time-loss injuries/hour cwu13 36 50 1.8 0.5 2.3 0.6 gku16 27 60 2.0 0.6 2.0 0.6 awu18 42 70 1.6 0.8 1.4 0.7 cwu18 27 70 1.7 0.6 1.5 0.5 combined tournament average 33 63 1.8 0.6 1.8 0.6 figure 1: injury incidence/1000 player hours and 95% confidence intervals of time-loss injuries for the youth week tournaments from 2011 2018. the dotted line reflects the average incidence for all tournaments over all the included years. 7 | p a g e only time-loss injuries were considered for further analyses. when the data were combined (2011 to 2018) there was a tendency for a slight decrease in injury incidence from u13 to u18, with the incidence tending to be lowest at the u18 craven week tournaments (figure 2). 23,5 22,3 19,6 17,7 0,0 5,0 10,0 15,0 20,0 25,0 30,0 35,0 40,0 45,0 cwu13 gku16 awu18 cwu18in ju ry i n ci d e n ce / 1 0 0 0 h o u rs tournaments time-loss injuires average lower 95%ci upper 95%ci poly. (time-loss injuires average) figure 2: injury incidence/1000 player hours and 95% confidence intervals of the youth week tournaments from 2011 2018. 8 | p a g e injury incidence trends u13 craven week there was an alternating increase-decrease pattern in injury incidence in the u13 craven week between 2011 and 2017. in 2018, however, a decrease in injury incidence was observed for the second consecutive year (figure 3). u16 grant khomo week there was a sizable decrease in injury incidence between 2017 and 2018, with the 2018 injury incidence being the second lowest recorded over the 8 years. the injury incidence decreased for the second consecutive year (figure 3). u18 academy week following a sizable decrease in injury incidence at the academy week between 2016 and 2017, there was a slight increase again in 2018 (figure 3). u18 craven week injury incidence gradually increased each year between 2014 and 2017. although not significant, a notable decrease in incidence was observed in 2018 (figure 3). this was the third lowest injury incidence recorded for this tournament. 9 | p a g e 16,7 27,8 19,4 30,0 18,9 28,9 25,6 21,1 y = -0,4271x2 + 4,2856x + 15,145 0,0 5,0 10,0 15,0 20,0 25,0 30,0 35,0 40,0 45,0 50,0 2011 2012 2013 2014 2015 2016 2017 2018 in ju ry i n ci d e n ce / 1 0 0 0 h o u rs u13 craven week 19,8 24,4 6,7 23,3 22,2 36,7 26,7 18,5 y = -0,2315x2 + 3,1697x + 13,922 0,0 5,0 10,0 15,0 20,0 25,0 30,0 35,0 40,0 45,0 50,0 2011 2012 2013 2014 2015 2016 2017 2018 in ju ry i n ci d e n ce / 1 0 0 0 h o u rs u16 grant khomo week 24,9 13,2 7,6 17,6 25,4 27,8 18,3 21,8 y = 0,2231x2 1,1504x + 19,046 0,0 5,0 10,0 15,0 20,0 25,0 30,0 35,0 40,0 45,0 50,0 2011 2012 2013 2014 2015 2016 2017 2018 in ju ry i n ci d e n ce / 1 0 0 0 h o u rs u18 academy week 28,6 18,7 21,9 6,7 8,6 19,0 21,9 15,9 y = 0,91x2 9,1355x + 35,566 0,0 5,0 10,0 15,0 20,0 25,0 30,0 35,0 40,0 45,0 50,0 2011 2012 2013 2014 2015 2016 2017 2018 in ju ry i n ci d e n ce / 1 0 0 0 h o u rs u18 craven week figure 3: time-loss injury incidence for each youth week tournament, per year, from 2011 2018. 10 | p a g e injury event when all tournaments in 2018 were combined, injuries most frequently occurred to the ball carrier (31%), followed by the tackler (25%). ball carriers had 5 injuries (3 to 7)/1000 player hours and the tacklers had 4 injuries (2 to 6)/1000 player hours. injury incidence to both the tackler and to the ball carrier tended to be highest in the u16 grant khomo week (table 3). when comparing injury rates of ball carriers vs. tacklers across the age-groups, it appears that in 2018, the younger age-groups were more prone to ball carrier injuries than to tackler injuries. figure 4 displays the proportion of injuries resulting from the different injury causing events. there was a reduction in the proportion of injuries arising from performing the tackle over the last three years, and an increase in the proportion of injuries from open play in 2018 compared to 2017. a similar pattern was observed from 2016 to 2017 (figure 4). of the injuries that occurred in open play in 2018; 7 were in contact events (collisions), and 8 were accidental in nature (slipped, side-stepping, landing). there was no one dominant injury type for injuries occurring in open play. table 3: injury incidence (95% ci)/1000 player hours of time-loss injuries to the tackler and ball carrier for the 2018 youth week tournaments. tournament tackler ball carrier cwu13 2 (1 – 5) 4 (0 – 9) gku16 6 (1 – 12) 7 (2 – 13) awu18 4 (1 – 7) 5 (1 – 8) cwu18 3 (0 – 7) 3 (0 – 7) combined total 4 (2 – 6) 5 (3 – 7) 11 | p a g e injury type in the 2018 tournaments the most common injury type was central/peripheral nervous system (cns/pns) injuries, which for all tournaments reflect concussions only (table 4, figure 5). there were no significant differences for any of the tournament x injury comparisons. however, the u18 academy week did seem to have the highest incidence of cns/pns and joint/ligament injuries. table 4: injury incidence (95% ci)/ 1000 player hours of time-loss injuries at the 2018 youth week tournaments grouped as joint/ligament, muscle/tendon and cns/pns injuries. tournament joint/ligament muscle/tendon cns/pns cwu13 1 (0 – 3) 1 (0 – 3) 4 (0 – 9) gku16 1 (0 – 4) 3 (0 – 6) 4 (0 – 8) awu18 7 (3 – 11) 3 (0 – 6) 9 (4 – 14) cwu18 2 (0 – 5) 3 (0 – 7) 3 (0 – 7) combined total 3 (2 – 5) 3 (1 – 4) 6 (3 – 8) figure 4: most common injury causing events in the youth week tournaments from 2011 2018. data label number represents the total number of injuries included in the bar graph) 12 | p a g e figure 5: most common injury types contributing to injury in the youth week tournaments from 2011 2018. (data label number represents the total number of injuries included in the bar graph) 13 | p a g e body location in the 2018 tournaments the most common injury location was the head/face (30%), with 46% of these head/face injuries occurring during the u18 academy week. all the injuries from the 2018 tournaments were grouped according to the four main body location groups (head & neck; trunk; upper body; lower body); head & neck injuries had the highest prevalence (48%) and incidence, 10 injuries (7 to 12)/1000 player hours (table 5). the u13 craven week had the highest tournament incidence of head and neck injuries; 13 injuries (6 to 21)/1000 player hours, but this was not significantly different from the other youth weeks. table 5: proportion (%) and incidence (95% ci)/1000 player hours of time-loss injuries, grouped by body location, in the 2018 youth week tournaments. proportion of injuries (%) incidence (95% ci)/1000 player hours head & neck 48 10 (7 – 12) trunk 2 1 (0 – 1) upper body 19 4 (2 – 6) lower body 27 5 (3 – 8) new vs recurrent the incidence of ‘new’ injuries in 2018 was 14 injuries (11 to 18)/1000 player hours. the ‘recurrent’ injuries were lower at 4 injuries (2 to 6)/1000 player hours. most of the ‘new’ injuries were to the muscle (75%), while most ‘recurrent’ injuries were joint injuries (50%). figure 6 depicts the proportion of ‘new’ and ‘recurrent’ ligament, joint and muscle injuries across the years. there was an increase in the proportion of ‘recurrent’ joint injuries from 2017 (20%) to 2018 (50%), while there was a decrease in the proportion of ‘recurrent’ muscle injuries from 2017 (38%) to 2018 (25%). 14 | p a g e game quarter injury occurrence was fairly evenly spread across the match quarters for the 2018 tournaments, with slightly more injuries occurring in the 3rd quarter (33%); 6 injuries (4 to 8)/1000 player hours. there has been no significant change in the distribution of injuries between quarters across the years (figure 8). figure 8: proportion of injuries occurring each game quarter in the youth week tournaments from 2011 2018. (data label number represents the total number of injuries included in bar graph) figure 6: proportion of new and recurrent ligament, joint and muscle injuries in the youth week tournaments from 2011 – 2018. (data label number represents the total number of injuries included in the bar graph) 15 | p a g e concussion there were 23 concussions in all the tournaments in 2018. this converted to an incidence of 6 injuries (3 to 8)/1000 player hours. the u18 academy week had the highest tournament incidence of concussion, 9 injuries (4 to 14)/1000 player hours. although this was almost 3 times the rate recorded at the u18 craven week tournament, this should be interpreted with caution because of the low numbers and wide confidence intervals (table 6). table 6: number and incidence (95% ci)/1000 player hours of concussions at the 2018 youth week tournaments. tournament number incidence cwu13 4 4 (0 – 9) gku16 3 4 (0 – 8) awu18 13 9 (4 – 14) cwu18 3 3 (0 – 7) combined total 23 6 (3 – 8) in the 2018 tournaments concussions to the tackler (22%) and to the ball carrier (22%) were similar (figure 9). figure 9: proportion of concussions caused by the different injury events at the 2018 youth week tournaments (n = 23 concussions). 16 | p a g e it appears as if there was an initial slight increase in the rate of concussions up to 2016 and then a gradual decrease. this pattern can be attributed to the interaction of several factors including greater awareness, evolving medical protocols and training techniques, and also to improved sensitivity in recognizing concussions (figure 10). figure 10: injury incidence/1000 player hours and 95% confidence intervals of concussions per year at the youth week tournaments from 2011 2018. there was a tendency for the combined concussion incidence (2011 – 2018) to decrease as the age of the players increased (figure 11). this pattern was similar to the pattern of time-loss injuries (figure 2). the changes in the concussion incidence across tournaments over time fluctuated (figure 12). for example, the concussions at the u18 academy week in 2018 increased from 2017, whereas the u18 craven week concussion rate was lower in 2018 compared to 2017. the u18 craven week and u18 academy week run concurrently and have the same medical support staff. this means that the increase in concussions at the u18 academy week in 2018 cannot be attributed to overzealous medical staff. this should be closely monitored in the future. 17 | p a g e 6,7 6,1 6,0 4,9 0,0 2,0 4,0 6,0 8,0 10,0 12,0 14,0 u13 cw u16 gk u18aw u18cw c o n cu ss io n i n ci d e n ce / 1 0 0 0 h o u rs tournaments concussions average lower 95%ci upper 95%ci poly. (concussions average) figure 11: concussion injury rate/1000 player hours and 95% confidence intervals per youth week tournament from 2011 2018. 18 | p a g e -5,0 0,0 5,0 10,0 15,0 20,0 25,0 2011 2012 2013 2014 2015 2016 2017 2018c o n cu ss io n i n ci d e n ce / 1 0 0 0 h o u rs u16 grant khomo week concussions -5,0 0,0 5,0 10,0 15,0 20,0 25,0 2011 2012 2013 2014 2015 2016 2017 2018c o n cu ss io n i n ci d e n ce / 1 0 0 0 h o u rs u18 academy week concussions -5,0 0,0 5,0 10,0 15,0 20,0 25,0 2011 2012 2013 2014 2015 2016 2017 2018c o n cu ss io n i n ci d e n ce / 1 0 0 0 h o u rs u18 craven week concussions -5,0 0,0 5,0 10,0 15,0 20,0 25,0 2011 2012 2013 2014 2015 2016 2017 2018c o n cu ss io n i n ci d e n ce / 1 0 0 0 h o u rs u13 craven week concussions figure 12: concussion incidence for each youth week tournament, per year, from 2011 2018. 19 | p a g e references 1. fuller cw, molloy mg, bagate c, et al. consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union. br j sports med 2007;41(5):328-31. doi: 10.1136/bjsm.2006.033282 [published online first: 2007/04/25] 2. schenker n, gentleman jf. on judging the significance of differences by examining the overlap between confidence intervals. the american statistician 2001;55(3):182-86. doi: 10.1198/000313001317097960 commentary 98 sajsm vol 23 no. 3 2011 introduction with the emergence of robust clinical research during this century and wide acceptance of the principles of evidence-based medicine, clinical case reports have been regarded with ambivalence. 1-3 it can be argued that they offer no credible evidence on the rate of clinical events, and no comparison or control group. furthermore, they are severely limited as a way of understanding risk factors and causes of disease, or efficacy of therapeutic or preventive interventions. despite these arguments clinicians often prefer to learn from case reports and use them as vehicles for continuing medical education. historically, case reports have played an important role in the medical literature, and from the 1940s to the 1970s comprised approximately 13% of articles in leading medical journals. 2 the lancet, new england journal of medicine and annals of internal medicine often publish clinical case reports as letters or even as original articles or through ‘clinical problem solving’ platforms. the british medical journal even has an electronic journal dedicated entirely to clinical case reporting (www.casereports.bmj.com/). there are numerous reasons for the documentation of case reports (table i). a case report can mark the beginning of a case series and eventually lead to an epidemiological study, clinical trials or intervention studies. sometimes case reports are the only source of information on rare or interesting events; indeed, our understanding of hiv disease began with the description of a single case. 4 case reports can entertain and encourage clinicians to think wider and to generate a hypothesis, and are valuable as part of a comprehensive database of other case reports which can be searched when necessary. the opportunity presented by sports and exercise medicine as clinicians involved in sports and exercise medicine, we work in an environment where human physiology (usually described at rest) is subjected to a stressor (exercise or sport), which can often result in injury or an abnormal clinical finding or unmask subtle disease. in addition, the health benefits of regular exercise in preventing disease have been well described. furthermore, regular exercise is increasingly recognised as a potent therapeutic intervention in patients with chronic disease and therefore more people are becoming physically active. sports and exercise medicine is still a relatively new discipline. therefore there are ongoing opportunities for the description of novel clinical entities, diagnostic work-ups and management strategies in all of the abovementioned aspects of the discipline. diagnosis in sports and exercise medicine involves a complex art of recognising patterns of illness and injury ̶ signs and symptoms can vary substantially from case to case. this task is made more difficult by the patient’s subjective description of his or her symptoms and perceived state of health. therefore the clinician’s approach needs to be based on a combination of carefully organised analysis of these signs and symptoms, a theoretical understanding of the basis of pathology, and an understanding of the physiological demands experienced during sport or exercise. the clinician’s thoughts progress through a series of intuitions, each providing a hypothesis, to be improved upon or rejected as determined by confirmatory findings. these findings are often in the form of results from special tests or investigations. hence, the final diagnosis is reliant on clinical experience developed during training and through professional practice. a closer analysis shows that clinical experience is based on the observation of accumulated clinical cases. in all cases, the goal of a case report is to convey a message that interests the readers of the journal and which is useful to everyone, including future patients with the same medical condition. writing a case report for publication writing a good case report is not only the recording and studying of cases of an unusual disease or disorder, but also a reflection of the art of choosing, gathering, structuring and conveying information about relevant clinical cases. it must lead to a better understanding of a given health problem and improved clinical decision making. it should focus on the reduction of information to be gathered rather than the accumulation of large amounts of data. there are excellent reference sources available to assist aspiring authors. 2,5-7 a clinical case report should be structured with the following headings: wayne e derman (mb chb, bsc (med)(hons), phd, facsm, ffims) research unit for exercise science and sports medicine, sports science institute of south africa, cape town correspondence to: wayne derman (wayne.derman@uct.ac.za) clinical case reporting in sports and exercise medicine table i. reasons for documentation of a case report • unusual presentation of unknown aetiology • unusual clinical course • challenging differential diagnosis • mistake in diagnosis or management • diagnostic or therapeutic side-effects • unusual or unexpected effect of treatment • description of novel technology used in diagnosis or management • unusual setting of therapy or care • description of a challenging situation related to medical ethics • single case ‘clinical trial’ • description of a clinical situation which cannot be reproduced for ethical reasons • confirmation of a rare but known entity sajsm vol 23 no. 3 2011 99 title there are typically two types of titles used in clinical case reporting. the first is one that directly informs the reader of the problem and the topic. the second is a ‘catchy’ or symbolic title that has an advertising quality to it, to entice the reader to read the complete case to understand the title. summary while a summary is not required by all medical journals, this section aims to attract the prospective reader and in a brief and organised manner convey the reasons for the report, the background to the problem and the most important highlights and conclusion. introduction the introduction should be brief and include the definition and context of the topic, pose a clinical question or highlight a gap that the case report can fill, and detail the objectives of the report. presentation of the case this section forms the main presentation of the clinical data and describes the triggering factor of the report, clinical findings, diagnostic and therapeutic steps, evolution of the case and expected or unexpected clinical outcomes. various components that may be included in this section of the case report are listed in table ii. consent for publication must be obtained from the patient or, if this is not possible, the next of kin before the case is submitted. discussion and conclusion in this section of the paper, the author has some freedom to analyse the findings of the case, compare the case with other cases of interest reported in the literature, formulate a conclusion and provide a recommendation for future work. the author should also specify the contribution of the case to the existing knowledge and literature. references this section should be kept to a minimum and only the references required for a basic understanding of the message of the case report should be included. there should be at least one reference included that covers the specific problem under study. summary sports and exercise medicine is a relatively new and growing discipline. it is a broad discipline that encompasses a wide area of clinical medicine. the patient population undertaking physical exercise as a lifestyle choice towards good health and longevity is increasing. sports and exercise medicine should therefore provide many interesting cases that could form an important part of the educational evidence into the future. many potential authors in clinical practice are not undertaking academic study or have not registered for higher degrees, yet still have a desire to share interesting clinical experiences with their colleagues. the clinical case report is an ideal format to fulfil this need. therefore, clinicians working in the exciting discipline of sports and exercise medicine are encouraged to contribute to the south african journal of sports medicine and their profession by making themselves familiar with the instructions for authors and writing and submitting their interesting clinical cases. references 1. o’brien pc. the use and misuse of n-of-one studies. int j oral maxillofac impl 1997;12:293. 2. jenicek m. clinical case reporting in evidence based medicine. 2nd ed. london: arnold, 2001. 3. braud w. in support of single-case clinical studies. altern ther health med 1998;4(3):88,119. 4. pneumocystis pneumonia ̶ los angeles. mmwr morb mortal wkly rep 1981;30(21):250-252. 5. charlton bg, walston f. individual case studies in clinical research. j eval clin pract 1998;4(2):147-155. 6. lawrence lw, jarreau pc, zitzmann mb. the use of clinical and management case studies to increase problem solving skills. clin lab sci 2001;14(1):9-12. 7. chopra r, lipman j, murphy tp. case studies in clinical practice development. semin intervent radiol 2005;22(1):56-60. table ii. components of the presentation of the case report • patient identification and characteristics (age, occupation, gender, level of athlete) • main complaint • complaint history and history of possibly related present and past health problems • patient history (medical, surgical, personal health, family, social, occupational, alternative medicine exposure, risk factors) • patient’s views/ideas about their problem, concerns and expectations • physical examination: relevant findings only • special investigations: laboratory, imaging or other technical results • differential and working diagnosis • immediate treatment and treatment plan • prognosis and patient follow-up statements are often made about ‘identifying talent’ as a means of addressing the imbalances in the demographics of the players in the top representative teams. politicians in particular make innuendos about coaches and administrators being selectively biased in their choice of certain players, at the exclusion of other players, hence slowing down transformation. however, what they fail to consider when making these statements is that a coach depends on a winning team for the longevity of his job. therefore it is disingenuous to think that a coach will place his or her job in jeopardy by not selecting the best players who can contribute to a winning team. attributing the lack of transformation to the coaches and administrators is simply a cunning way of taking the focus off the real source of the problem. the real source of the problem has a wider context than merely being the bias of coaches and administrators. the real source of the problem can be attributed directly to the inequities that exist from childhood in different regions of the country. preparation begins at preschool, where the child should have access to healthy adequate nutrition and an opportunity to develop fundamental motor skills. if these basic conditions are not provided the child encounters a hurdle which persists through to adulthood. the talented sports stars who represent our nation do so because they have well-refined skills and have had the opportunity from a very early age to develop and sharpen their skills. the development of motor skills is sequential – if any layer of development is incomplete, the next layer will be affected. there are windows of opportunity in which skills are developed, and if these opportunities are bypassed, the chances of developing them at a later stage are limited. a recent study of the fitness of south african children has shown that children from poorer areas under-perform in tasks of physical performance compared with children from more affluent areas. 1 the differences can be attributed to the smaller size of the children from poor areas as well as underdeveloped motor skills. in this particular study the differences skills were noticeable in grade 1. the most important training ground for skill development occurs at school. until such time as all the schools have similar facilities and opportunities to participate in physical activity, our children will always have a range of developed skills which will persist through to adulthood. suffice to say, it is highly unlikely a talented child coming from a deprived background will ever be able to compete equally with a talented child who has had an opportunity to develop his or her talent fully. there are many studies which demonstrate this. to excel in high-level sport it is essential to implement a longterm athlete development programme. 2 this type of programme considers and caters for the unfolding need to develop skill. a wellconstructed long-term athlete development programme reduces the advantages that early maturation might have, 3 and results in a much larger pool of talented adult players from which the national team can be selected. surely it is time that the political decision-makers faced the facts and addressed the problem of lack of transformation on the sports field by focusing attention on schools and ensuring that facilities in the poor schools are upgraded to match the facilities in the schools from more affluent areas. failure to do so will ensure that the situation we currently have will persist into the next generation. shifting the attention and blame to the coach and sporting federation is a cheap shot which exposes their ignorance and lack of understanding of the principles of talent development. sustainable changes are beyond the influence of the sporting federations, and remain firmly with the government, in particular the departments of education, sport and health. if the long-term athlete development model was understood and embraced by these departments, the concern of having national teams which do not represent the demographics of the general population will be a thing of the past. this brings us to the contents of this edition of the journal. the concept of the long-term athlete development model is discussed with reference to rugby. the procedures adopted in south africa are compared with the procedures of australia and new zealand. in addition the abstracts and posters presented at the 4th clinical sports medicine conference – injury preven tion and protection of the health of the athlete, 13 15 oc tober 2010, cape town, are published in this edition. this edition also includes a paper which shows that the elite athletes drink much less than the recommendations suggest. apart from making this finding this study also shows how important questions can be answered by substituting a large budget with a creative research plan. there is also a practical evidenced-based article on pre-participation screening for rugby players (‘boksmart: pre-participation screening of rugby players by coaches based on internationally accepted medical standards’). this paper was one of the papers commissioned by boksmart. more excellent practical papers on injury prevention, rehabilitation and training for rugby can be found at www.boksmart.com. finally, dr maaki ramagole co-ordinated the development of the sasma position statement on managing athletes with disorders of sexual development (dsd). this document will serve as a guideline for managing disorders of sexual development in future and will avoid a repetition of the unpleasant situation we experienced last year. there are many interesting articles in this edition – we hope you enjoy the read! mike lambert editor-in-chief 1. armstrong me. youth fitness testing in south african primary school children: national normative data, fitness and fatness, and effects of socioeconomic status. phd thesis, university of cape town, 2009. 2. vaeyens r, lenoir m, williams am, philippaerts rm. talent identification and development programmes in sport : current models and future directions. sports med 2008;38(9):703-714. 3. malina rm, brown ew. growth and maturation of football players: implications for selection in youth programs. insight 1998;2(1):27-30. lack of transformation in sport and the long-term athlete development programme a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial 54 sajsm vol 22 no. 3 2010 � sajsm vol 20 no. 1 2008 introduction anterior cruciate ligament (acl) rupture is one of the most common debilitating knee injuries. 36 this knee injury is commonly sustained by individuals participating in sporting activities that require pivoting, jumping and decelerating actions. 6, 36 immediately after an acl injury, the athlete experiences significant functional limitations due to significant swelling and pain. 14,37 athletes are generally eager to return to their usual level of sporting activity and often also experience psychological distress as the recovery process usually lasts for a few months. 18,37 the management of an acl injury may be conservative or surgical. 16,18 however, surgical reconstruction is currently the most common approach in the management of acl injuries. 8,22,41 the functional outcome after surgical reconstruction appears to be more favourable compared with that of non-surgical management approaches. 1 however, despite advances in acl repair after reconstructive surgery to optimise the mechanical stability, functional instability of the knee may still be evident in the post-surgery stage. 2 physical rehabilitation plays an important role in retraining functional stability of the knee joint after knee surgery. 18 it has also been found that functional rehabilitation was the most important positive prognostic factor for predicting early return to sport. 18 physiotherapists have the opportunity to select the most appropriate rehabilitation protocol for the specific acl-injured individual from a range of rehabilitation approaches. prolific review effectiveness of early quadriceps exercises after anterior cruciate ligament reconstruction abstract objective. to systematically review the published information regarding the effectiveness and safety of early post operative quadriceps muscle exercise training on pain, joint laxity, function and range of motion in postoperative anterior cruciate ligament (acl) reconstruction adult patients. data sources. five databases (cinahl, pedro, pubmed, science direct and the cochrane library) were searched for studies published from january 1990 to may 2007. study selection. publications describing research into the effectiveness of early quadriceps exercises after acl reconstruction were included. a total of three eligible articles met the inclusion criteria. data extraction. a review of the three eligible studies was undertaken to describe the key study components. the pedro scale was used to determine the methodological quality of the selected trials and the level of evidence of all the eligible studies was categorised according to the evidence hierarchy by lloyd-smith. 24 relevant data were extracted by the two reviewer groups to reduce bias. data synthesis. due to study heterogeneity a meta-analysis could not be conducted. effect sizes were calculated provided that sufficient data were provided. outcome measures included range of motion (rom), functional performance, pain correspondence: quinette louw division of physiotherapy stellenbosch university p o box 19063 tygerberg 7505 south africa tel: 27 21 938 9300 fax 27 21 931 1252 e-mail: qalouw@sun.ac.za candice permall (bsc physiotherapy) alet van wyk (bsc physiotherapy) anneen van zyl (bsc physiotherapy) tihanna vorster (bsc physiotherapy) quinette louw (bsc, masp, phd) division of physiotherapy, stellenbosch university, south africa and knee laxity. the methodological quality of the studies did not vary considerably across the studies and the average pedro score was 66%. marginal significant differences were noted in knee rom at 1 month postoperatively, pain day 1 postoperatively, knee laxity and subjective evaluation of function at 6 months postoperatively. conclusion. early quadriceps exercises can be performed safely in the first 2 postoperative weeks, but clinically significant gains in rom, function, pain and knee laxity were not evident. further research should include standardised interventions, measurement time frames and outcome measurement tools to allow for a metaanalysis to be conducted. pg4-20.indd 4 4/23/08 11:30:52 am sajsm vol 20 no. 1 2008 � research has been published on rehabilitation protocols after acl reconstruction. 34 published research in the 1980s focused on the effectiveness of electrical stimulation of the quadriceps muscle in the acute postoperative stage to decrease the effect of muscle atrophy and weakness. 28 more recently, the focus of published research has been on accelerated versus non-accelerated rehabilitation programmes, as well as open-kinematic chain versus closed-kinematic chain exercises in early rehabilitation after acl reconstruction. 5,9 anecdotally, it is proposed that accelerated rehabilitation programmes that allow early range of motion (rom), immediate weight-bearing and early return to previous functional level should be advocated as best practice. however, these recommendations for best practice are often based on clinical opinion and not on research evidence. 9 clinical decision-making regarding the most appropriate exercises should be based on research evidence. 9 appropriate neuromuscular function of the quadriceps muscle group is required during static and dynamic function of the lower limb. 27 inadequate quadriceps muscle strength may result in functional instability of the knee joint after acl injury or reconstruction. 21 quadriceps muscle weakness is a common sequel after acl surgery. 40 quadriceps dyskinesia and weakness follow acl injury due to neural and physiological changes such as the loss of acl mechanoreceptor feedback, abnormal gamma loop function of the quadriceps femoris muscle, atrophy of muscle fibres and neural activation deficits. 17,30 to prevent weakness of the quadriceps muscle and knee extension lag, physiotherapists commonly prescribe quadriceps exercises after acl reconstruction as early as possible during the inpatient rehabilitation phase. 34 however, given the high costs of surgery and lengthy rehabilitation, the costeffectiveness of prescribing early quadriceps exercises has been questioned. 34 furthermore, the safety of early quadriceps muscle strengthening after acl reconstruction may also be of concern as postoperative anterior-posterior laxity could compromise the integrity of the acl. 15 quadriceps muscle contraction produces a rotatory component around the knee joint axis, and also creates a translatory component that causes an anterior shear of the tibia on the femur. 20 the acl creates an antagonistic pull to resist this anterior shear produced by the quadriceps contraction and by doing so, provides stability to the knee. 20 there is thus strain on the acl during active quadriceps muscle contraction, mainly in the last 45 degrees of extension, which could compromise the integrity of the graft. 30 the aim of this review was therefore to systematically appraise the effect of early postoperative quadriceps exercise training on pain, joint laxity, rom and function, compared with a rehabilitation programme not allowing early quadriceps exercises or restricting quadriceps exercise training to only isometric quadriceps contractions in postoperative acl reconstruction patients aged between 17 and 44 years. methodology the specific objectives of the review were to: • describe the type of quadriceps exercises implemented in eligible randomised controlled trials • describe the outcome measures used to assess pain, knee joint laxity, rom and function after acl reconstruction • assess the effectiveness and safety of early postoperative quadriceps exercise training on pain, joint laxity, function and rom when compared with a rehabilitation programme not allowing early quadriceps exercises or restricting quadriceps exercise training to only isometric quadriceps contraction in postoperative acl reconstruction patients aged between 17 and 44 years. the following definitions were used in this review: • early quadriceps exercises: any active lower limb activity aimed specifically at contraction of the quadriceps to achieve full-range knee extension and performed within the first 2 weeks or in the in-patient phase after acl reconstructive surgery. 32,34,38 • acl reconstruction: the surgical repair of the acl after complete acl rupture or recurrent ligament injury. 10 all types of grafts including bone-patellar tendon-bone, bone-tendonbone, semitendinosus-hamstring and semitendinosus-gracilis grafts were included in this review. 35 • knee instability: the lack of physiological anterior posterior (a-p) and rotational steadiness of the knee joint. 42 manual clinical tests to evaluate knee instability include the anterior draw, lachman’s and pivot shift tests. 33 the kt-1000 arthrometer is a popular instrument for measuring knee instability. 33 • function: the ability to safely perform weight-bearing activities including gait, stair climbing and pre-injury function. 21,38 shaw et al. described a number of tests used to assess function, including the single and triple hop tests, timed hop tests, vertical jump tests, stairs hopple test and figure eight running. 33 • pain: the experience of knee pain as measured with validated pain scales such as the visual analogue scale (vas). 4 • range of motion (rom): the amount of motion, measured in degrees, available to a joint within the anatomic limits of the joint structure. 20 active and passive range of flexion and extension of the knee can be assessed objectively with a goniometer. 33 search strategy prior to commencing this project, the cochrane library and pedro were searched to ascertain if a similar review had not been published within the past 5 years. the search findings indicated that a similar review had not been published. search strategies were developed for the following computerised bibliographical databases: cinahl, pedro, pubmed, science direct and the cochrane library. these databases were available via the university of stellenbosch library and the world wide web. all databases from january 1990 to may 2007 were searched. each search strategy was developed according to the functions of each database group as follows: • group 1: databases where papers are classified according to their medical subject headings (mesh) and key terms. these databases allow for terms to be combined (pubmed, cinahl, the cochrane library). pg4-20.indd 5 4/23/08 11:30:53 am � sajsm vol 20 no. 1 2008 • group 2: databases where key terms are used to classify papers. these databases have a limited ability to combine key terms (science direct, pedro). a detailed search strategy for each of the selected databases was designed. the key search terms were anterior cruciate ligament, acl, reconstruction, repair, rehabilitation, strengthening, pain, function, exercises. mesh terms were used in pubmed. in addition, a secondary search (pearling) was conducted by screening the reference lists of all potential full-text articles. to ensure that eligible articles not indexed in the electronic databases were not missed, the authors of the eligible articles were contacted via e-mail. eligibility criteria for inclusion this review included primary research randomised-controlled clinical trials with an acceptable methodological quality appraisal score of at least 4 out of 11 on the pedro scale. 7 studies reporting on males and females aged between 17 and 44 years, who underwent unilateral acl reconstruction of either the right or left knee by the use of any type of graft, were considered eligible for this review. the eligible age was determined by skeletal maturity that is present over the age of 16 years. 36 articles reporting on patients with common acl-associated injuries such as medial meniscal injuries were considered eligible since isolated acl injuries are rare and do not replicate the population of acl reconstructions generally managed by physiotherapists. studies reporting on participants who underwent previous acl reconstruction on the reconstructed knee, sustained injury to the contralateral knee or presented with any other rheumatological, neurological, cardiovascular or congenital condition that could affect lower-limb function and result in disability, were excluded from this review as they would not reflect the true outcome of this specific intervention. 36 the interventions of the studies also determined eligibility. studies that included one treatment group who performed early quadriceps exercises within the first 2 weeks postoperatively and a control group who underwent rehabilitation excluding early quadriceps exercise training or only allowing early isometric quadriceps exercise training were considered eligible for this review. eligible studies reporting on the following outcome measures were considered for this review: • active range of flexion and extension of the knee as measured with a goniometer. 33 • pain experienced as measured with the visual analogue scale or other published validated pain scales. 4 • knee stability as measured with the kt-1000 arthrometer or other validated knee-instability scales. 33 • lower-limb function as determined by functional tests including the single and triple hop tests, timed hop tests, vertical jump tests, stairs hopple test, figure eight running and other relevant functional tests. 33 the two reviewer groups screened all hits and selected relevant titles independently. differences between pairs were discussed until consensus was reached and the fifth author was consulted to resolve any disagreements. assessment of methodological quality in order to determine the internal validity of the eligible trials, the pedro scale was used (table i). the pedro scale is commonly used in research to critically evaluate randomised controlled trials. 25 evidence hierarchy the level of evidence of all the studies included in this review was evaluated using the evidence hierarchy by lloyd-smith. 24 • 1a: meta analysis of randomised controlled trials • 1b: one individual randomised controlled study • 2a: one well-designed, non-randomised controlled study • 2b: well-designed quasi-experimental study • 3: non-experimental descriptive studies – comparative/case studies • 4: respectable opinion. study designs fulfilling the ‘1b’ criteria were considered eligible for inclusion. data extraction the four reviewers were divided into two reviewer groups to extract the data. this was done independently by each of the two reviewer groups. the fifth author was consulted to resolve any discrepancies between the two reviewer groups. the following information was extracted: publication date, authors, journal, study design, setting, pedro score, aim, description of participants, type of grafts, author’s conclusion, clinical relevance, number of participants, description of interventions and outcome measures used. data synthesis the three eligible studies presented heterogeneity with respect to the exercise interventions performed, the outcome measurement tools used and the time frames of measurement. therefore it was not possible to perform a meta-analysis. the effect size was calculated with the available data where significant differences between groups were reported by the authors. the effect size represents the clinical magnitude of difference between groups. 29 a greater observed effect represents a larger significant difference. 29 one of the eligible studies, shaw et al. reported sufficient data (mean and sd) to calculate the effect size. 34 results search results the results of the search strategy are presented in a flow chart (fig. 1). three articles were considered eligible – from australia, sweden and germany. 11,15,34 evidence hierarchy the three selected studies were rcts, representing level ‘1b’ evidence according to the grading system of lloyd-smith. 24 methodological quality appraisal there was 100% agreement between the two reviewer groups regarding the methodological score. the average methodological quality score was 66% (table i). pg4-20.indd 6 4/23/08 11:30:54 am sajsm vol 20 no. 1 2008 � table i. summary of the pedro scores pedro criteria shaw isberg friemert et al. 34 et al. 15 et al. 11 eligibility criteria were specified √ √ subjects were randomly allocated to groups √ √ √ allocation was concealed √ √ groups were similar at baseline regarding important prognostic indicators √ √ blinding of all subjects blinding of all therapists who administered the therapy blinding of all assessors who measured at least one key outcome √ measures of at least one key outcome were obtained from more than √ √ √ 85% of the subjects initially allocated to groups subjects for whom outcome measures were available received the √ √ √ treatment or control condition, if not, data for at least one key outcome was analysed by ‘intention to treat’ results of between-group statistical comparisons are reported for at least one key outcome √ √ √ provided both point measures and measures of variability for at least one key outcome √ √ √ total score 8/11 7/11 7/11 table ii. sample descriptions shaw et al. 34 isberg et al. 15 friemert et al. 11 sample size 103 22 60 surgical procedure unilateral arthroscopically unilateral acl unilateral acl assisted acl arthroscopic reconstruction reconstruction reconstruction graft type : graft type: graft type: bone-patellar tendon patellar tendon autograft bone-tendon-bone bone autograft semitendinosus quadrupled semi hamstring graft tendinosus/gracilis autografts age of participants older than 18 yrs median (range): mean age: 28.6 ± 8.8 yrs 21 yrs (17– 41 yrs) mean age: 23 ± 3.6 yrs inclusion criteria all of the above no history of injury or any acl rupture, iiº iiiº other symptoms of mechanical instability or provided informed contralateral knee clinical giving way sign consent age ≤ 35 yrs healthy contralateral leg exclusion criteria previous surgery on multiple knee ligament brace treatment reconstructed knee injuries of ipsilateral knee (except for arthroscopy) additional knee history of previous knee ligament injuries previous acl injury or surgery of reconstruction on either ipsilateral knee contraindications for knee use of devices additional repair of sustained concurrent meniscal tears of limited rom due to surgery injury to contralateral knee ipsilateral knee any knee problems of neurological and vascular received simultaneous contralateral knee problems/ diseases collateral ligament repair post-op infection unlikely to attend follow-up injury to hip and/or ankle pg4-20.indd 7 4/23/08 11:30:55 am 8 sajsm vol 20 no. 1 2008 description of study samples information regarding participants in each study according to the sample size, age, surgical procedure and inclusion and exclusion criteria was tabulated (table ii). sample sizes differed across the three studies and the means sample size was 61. the mean age of the samples in the three studies was comparable and none of the studies included participants older than 41 years of age. according to the inclusion and exclusion criteria, all three studies excluded contralateral knee injuries or multiple ligament injuries of the reconstructed knee. a history of previous knee injury or surgery of the reconstructed knee was excluded for shaw et al. and isberg et al. 15,34 description of exercise interventions the exercise programmes performed by the intervention and control group for each of the three studies are described in table iii. the intervention groups of all three studies performed early quadriceps exercises within the first 2 postoperative weeks. the control groups did not perform early quadriceps exercises except for friemert et al., where only early isometric strengthening exercises were allowed in the first postoperative week. 11 description of the outcome measures the outcomes measures and measurement time frames utilised are summarised in table iv. range of motion was the only outcome measure utilised in three studies. effectiveness of early quadriceps exercises the effectiveness of early quadriceps exercise training is presented according to each outcome measure. table iii. a description and comparison of the specific exercise interventions intervention control group exercises duration of group performed by both interventions groups shaw et al. 34 specific no specific general exercise first 2 quadriceps quadriceps programme postoperative exercises : exercises consisting of: weeks • straight leg • foot and ankle raises exercises • isometric • active assisted quadriceps knee flexion contractions • calf stretches (10 x 3 daily) • passive knee extension • standing posture • gait education • passive knee extension with weight isberg et al. 15 full active and full active and rehabilitation brace first 4 passive knee passive knee and postoperative postoperative extension between extension between rehabilitation weeks 30° and -10° was 30° and -10° was programme allowed, not allowed, immediately immediately postoperatively postoperatively, thus restricting active and passive knee extension friemert et al. 11 continuous active continuous postoperative day 1 7 motion (cam) of passive motion rehabilitation postoperative knee flexion and (cpm) of knee programme, including extension flexion and isometric extension strengthening exercises and partial weight-bearing databases initial hits accepted titles/ abstracts duplicates cinahl n = 52 5 17 pedro n = 350 20 26 pubmed n = 298 21 48 science direct n = 247 15 13 the cocharane collaboration n = 542 59 12 total n = 1 489 119 116 fig. 1. results of the search strategy. excluded article titles n = 1 369 (initial hits – accepted titles) articles excluded as the titles were not relevant to the research question potentially eligible study titles/abstracts: n = 119 excluding abstracts and their duplicates: abstracts were excluded because they either did not meet inclusion/ exclusion criteria or they were duplicates eligible articles: n = 3 fig. 1. results of the search strategy. pg4-20.indd 8 4/23/08 11:30:57 am sajsm vol 20 no. 1 2008 � range of motion shaw et al. measured three ranges over the 6-month follow-up period, namely: active knee flexion, active knee extension and passive knee extension relative to neutral, but the measurement tool was not mentioned. 34 they used mean differences and 95% confidence intervals to determine significant differences between the intervention and control groups. 34 significant between-group differences (table v) in active knee flexion and extension 1 month postoperatively were reported. however, it is notable that the lower 95% confidence intervals for both active knee flexion and extension are only marginally significant as they are close to zero. the effect size for knee flexion was 0.44 (medium effect) and 0.48 (medium effect) for extension 1 month postoperatively. the effect size for active knee flexion in the study by friemert et al. was 0.15 (small effect) at 7 days postoperatively. 11 functional performance shaw et al. objectively evaluated function by means of the functional hop tests consisting of the single-leg-hop and the tripleleg-hop tests (table vi). 34 measurements are given as a percentage difference of the reconstructed leg strength relative to the non-operative leg by shaw et al. and isberg et al. 15,34 shaw et al. assessed function 6 months postoperatively and confidence intervals span zero, indicating no between-group significant differences. 34 isberg et al. objectively evaluated function pre-operatively, at 6 months postoperatively and at 2 years follow-up by means of the single-leg-hop test. 15 no significant differences between the groups were found. the third study by friemert et al. did not report on function objectively. 11 function was subjectively evaluated using outcome measurement scales in two of the studies. 15,34 the lysholm score, tegner score and international knee documentation committee (ikdc) evaluation system were used by isberg et al. 15 these measurements were taken preoperatively and at 2year follow-up. negligible differences were found between the groups at 2 years. shaw et al. used the cincinnati knee rating system (ckrs) for subjective assessment of function. 34 the ckrs is a unique rating system that consists of several subdivisions that provide questionnaires for symptoms, function and occupation. 33 the fig. 2. pain as measured by vas for friemert et al.11 pain lev el : cpm v s cam 1.2 4 1.2 4 3.1 2.9 1.8 1.9 0 1 2 3 4 5 p re -o p d ay 0 po st op d ay 2 po st op d ay 7 po st op tim e point v a s cpm cam fig. 2. pain as measured by vas for friemert et al. 11 table iv. description of outcome measures time of measurement outcome study outcome measure pre-op day 0 day 1 day 2 day 7 2 weeks 1 mnth 3 mnths 6 mnths 2-yrs rom shaw not explicitly √ √ √ √ √ et al. 34 stated isberg standard √ √ √ et al. 15 handheld goniometer friemert not explicitly √ √ et al. 11 stated function shaw single-hop et al. 34 test triple-hop √ test isberg single-hop √ √ √ et al. 15 test pain shaw 10 cm vas √ √ √ √ √ et al. 34 friemert 10 cm vas √ √ √ √ et al. 11 knee shaw kt-1000 √ √ laxity et al. 34 isberg kt-1000 √ √ √ et al. 15 rsa pg4-20.indd 9 4/23/08 11:30:59 am 10 sajsm vol 20 no. 1 2008 measures were taken at 1, 3 and 6 months postoperatively. at 6 months postoperatively, statistically significant differences between the groups were demonstrated for the subdivision ‘problems with sport’. the intervention group had a higher (more favourable) score than the control group for the ‘problems with sport’ category (table vii). however, the 95 % ci spans 0 and the effect size we calculated were 0.33, indicating that the effect of the early quadriceps exercises was small. pain assessment according to shaw et al. there was no statistically significant difference between the groups for pain perception at any follow-up intervals (table viii). 34 however, in the qua driceps exercise group, significantly greater pain with exercise performance was measured on the first post operative day. findings of the studies conducted by friemert et al. did not demonstrate significant differences in preoperative pain measurements on the operative day and on the second and seventh day postoperatively (fig. 2). 11 isberg et al. did not report on pain as an outcome measure. 15 shaw et al. further evaluated pain by means of die ckrs evaluation system. 34 six months postoperatively the intervention group reported significantly higher (more favourable) results for pain calculated under the ckrs subdivision ‘symptoms’ (table ix). however, the lower confidence interval is marginally significant (0.2). the effect size calculated as 0.62, indicating that the early quadriceps exercises had a moderate on pain perception. knee laxity shaw et al. measured a-p laxity by means of the kt1000 using a 15-pound, 20pound and maximal manual test force. 34 measurements, presented in table x, were taken 3 and 6 months postoperatively. a-p side-to-side differences of greater than 3 mm or greater than 5 mm were used as cut-off points during testing as these were seen as indications of abnormal laxity. for each test force, shaw et al. retrieved the number of abnormally t a b l e v . m e a n , s ta n d a rd d e v ia ti o n a n d 9 5 % c o n fi d e n c e i n te rv a ls f o r r o m m e a s u re d i n d e g re e s a c ti v e k n e e fl e x io n a c ti v e k n e e e x te n s io n p a s s iv e k n e e e x te n s io n m e a n ( s d ) m e a n ( s d ) m e a n ( s d ) in te r c o n tr o l m e a n in te rv e n ti o n c o n tr o l m e a n i n te r b = c o n tr o l m e a n v e n ti o n d if fe re n c e d if fe re n c e v e n ti o n d if fe re n c e ( 9 5 % c i) ( 9 5 % c i) ( 9 5 % c i) p re -o p is b e rg e t a l 1 5 n o v a lu e s g iv e n . is b e rg e t a l.1 5 s ta te d t h a t r o m d id n o t d iff e r b e tw e e n t h e g ro u p s. f ri e m e rt e t a l.1 1 1 3 9 .5 ( 1 3 .8 ) 1 3 7 .5 ( 1 6 .4 ) _ _ _ _ d a y 1 s h a w e t a l.3 4 7 3 .8 ( 2 0 .3 ) 7 7 .1 ( 2 1 .6 ) -3 .3 ( -1 1 .5 -2 2 .5 ( 8 ) -2 2 .4 ( 7 .9 ) -0 .1 ( -3 .8 -1 2 .7 ( 6 .4 ) 11 .8 ( 6 .1 ) -0 .9 ( -3 .6 p o st o p t o 4 .9 ) to 3 .6 ) to 1 .8 ) d a y 7 f ri e m e rt e t a l.1 1 1 0 1 ( 1 7 ) 9 5 ( 1 4 ) n o v a lu e s g iv e n b u t f ri e m e rt e t a l.1 1 _ _ p o st o p st a te d t h a t a ll p a tie n ts r e a ch e d f u ll e xt e n si o n a t th is p o in t in t im e . 2 w e e ks s h a w e t a l.3 4 1 0 4 .9 ( 1 5 .3 ) 1 0 1 .8 ( 1 5 ) 3 .1 ( -3 .4 -1 6 .5 ( 6 .1 ) -1 9 .2 ( 6 ) 2 .7 ( -0 .1 9 ( 5 .4 ) -9 ( 5 .6 ) 0 ( -2 .4 p o st o p t o 9 .6 ) to 5 .5 ) t o 2 .4 ) 1 m n th s h a w e t a l.3 4 1 2 8 .2 ( 1 2 .7 )* 1 2 2 .3 ( 1 4 .5 )* 5 .9 ( 0 .1 -1 2 .1 ( 4 .8 ) * -1 4 .8 ( 6 .4 ) * 2 .7 ( 0 .1 -6 .5 ( 4 .2 ) 7 .7 ( 5 ) 1 .2 ( -0 .8 p o st o p t o 1 1 .7 )* to 5 .3 ) t o 3 .2 ) 3 m n th s s h a w e t a l.3 4 1 3 8 .9 ( 8 .1 ) 1 3 9 .9 ( 8 ) 1 ( -4 .5 -7 .4 ( 4 .4 ) -7 .7 ( 4 .5 ) 0 .3 ( -1 .8 -4 .2 ( 3 .7 ) 3 .8 ( 3 .1 ) -0 .4 ( -1 .9 p o st o p t o 2 .5 ) to 2 .4 ) t o 1 .1 ) 6 m n th s is b e rg e t a l.1 5 n o v a lu e s g iv e n . is b e rg e t a l.1 5 s ta te d t h a t r o m d id n o t d iff e r b e tw e e n t h e g ro u p s p o st o p s h a w e t a l.3 4 1 4 1 .6 ( 6 .9 ) 1 4 2 .6 ( 7 .6 ) -1 ( -4 .1 -5 .7 ( 4 .1 ) -4 .9 ( 4 .2 ) 0 .8 ( -2 .7 -3 .1 ( 3 .4 ) 2 .3 ( 3 .2 ) -0 .8 ( 2 .2 t o 2 .1 ) to 1 .1 ) t o 0 .6 ) 2 y rs is b e rg e t a l.1 5 n o v a lu e s g iv e n n o v a lu e s n o s ig n ifi ca n t d iff e re n ce b e tw e e n g ro u p s fo llo w -u p g iv e n w h e n c o m p a ri n g t h e in ta ct a n d r e co n st ru ct e d kn e e f o r e a ch in d iv id u a l p a tie n t _ _ = n o m e a su re m e n t ta ke n . * si g n ifi ca n t d iff e re n ce ( p < 0 .0 5 ). 1 2 8 .2 ( 1 2 .7 )* 1 2 2 .3 ( 1 4 .5 )* 5 .9 ( 0 .1 1 2 .1 ( 4 .8 )* -1 4 .8 ( 6 .4 ) * 2 .7 ( 0 .1 t o 1 1 .7 )* t o 5 .3 )* pg4-20.indd 10 4/23/08 11:31:01 am sajsm vol 20 no. 1 2008 11 lax knees and compared this with the number of subjects measured. 34 the total number of subjects presenting with lax knees were calculated with the available data. the control group demonstrated a significantly greater number of subjects with laxity at each test force 6 months postoperatively. no significant differences were noted 3 months postoperatively. isberg et al. used the kt-1000 and radiostereometric analysis (rsa) to evaluate ap laxity preoperatively, 6 months postoperatively and at 2-year follow-up. 15 no significance between group differences was found at any point of measurement. however, there was a statistically significant reduction in a-p laxity within each group from the pre-operative period until the 2-year follow-up (table xi). discussion this paper reports on the effectiveness of early quadriceps exercise after acl reconstruction and illustrates the sparse literature available to determine the effect of this common physiotherapeutic intervention in this patient intervention. physiotherapists commonly prescribe static isometric quadriceps exercises early postoperatively, with the aim of restoring neuromuscular function of this muscle as soon as possible. 34 however, the findings of this paper demonstrate that this usual practice procedure may not apply to all patients and requires reconsideration. the three eligible papers had common methodological limitations. all three studies have not met the blinding of subjects and therapists criterion. blinding of therapists and patients in exercise intervention studies is impossible in the majority of trials as the therapists and patients can often differentiate between intervention and placebo exercises for a specific patient population. 12 therefore, although there was heterogeneity with respect to sample size, exercise interventions, outcome measurement and data analysis, the methodological quality of the studies is comparable. the methodological quality of the studies was deemed acceptable, evidenced by the critical appraisal findings and therefore the internal validity is considered to be sound. however, since all the trials were conducted at one conveniently selected clinic, the external validity of the studies may be limited. furthermore, only one of the studies indicated that a sample size calculation was conducted. 11 the range of the sample sizes was 22 -103 participants among the three studies and, according to shaw et al., were relatively small when compared with the number of acl reconstructions performed internationally. 34 a larger sample size is likely to be a more accurate representation of a population and will thus produce more recognisable betweengroup statistically significant differences. 29 therefore the power of the remaining two studies has not been indicated, highlighting the limitations with respect to external validity of the findings. the age of participants ranged from 17 to 41 years in the three selected studies. adolescents and young adults who are physically active in sports are usually at an increased risk of an acl injury. 24 therefore the age group of subjects represents the high-risk group for acl injuries. 6,24,36 the descriptions of the samples, however, lack specific information about the level and type of sporting activity, which may reflect different levels of motivation to engage in exercise therapy and return to sporting activity. a few months’ absence from competition and sport may result in detrimental socio-economic consequences for professional athletes, 31 who are usually more motivated to commence their rehabilitation process at an earlier stage compared with recreational athletes or sedentary individuals. it may therefore be important to assess the outcome of this early exercise intervention within patient populations with a specific level of sporting activity as the psychological benefits of early rehabilitation may be advantageous in competitive athletes. the outcomes measurement tools used in the selected studies were valid and reliable. 13,19 the goniometer, kt1000, visual analogue and functional hop tests are valid and reliable outcome measures according to the findings of a published systematic review. 33 according to isberg et al. the radiostereometric analysis (rsa) is a reliable and valid outcome table vi. results of functional tests – a quotation (%) between the intact and the injured knee single-leg-hop triple-leg-hop intervention control mean intervention control mean difference difference (95% ci) (95% ci) pre isberg operative et al.15 82 80 not not median (0-96) (0-96) measured measured (range) 6 mnths shaw et al.34 83.8 (10.1) 81.7 (12.7) 2.1 (-2.8 to 7) 83.7 (11.4) 81.8 (13.6) 1.9 mean (sd) (-3.5 to 7.3) 24 mnths isberg et al.15 97 96 median (86-100) (85-100) not measured not measured (range) table vii. function as measured with ckrs ‘problems with sport’ category (shaw et al.34) intervention control mean mean (sd) mean (sd) difference (95% ci) 1 mnth 40.2 (11.6) 41.6 (11.9) -1.4 (-6.2 to 3.4) post op 3 mnths 55.2 (12.5) 51.2 (12.4) 4 (-1.2 to 9.2) post op 6 mnths post op *p<0.05. 66.4 (14.4)* 61.6 (15.2)* 4.8 (-1.4 to 11)* pg4-20.indd 11 4/23/08 11:31:02 am 12 sajsm vol 20 no. 1 2008 measure. 15 however, differences in outcome measurement time frames and interpretation did not allow for a meta-analysis of the outcome data. shaw et al. recommended that key outcome measures should be used at specific time frames postoperatively, in order to optimise the sensitivity of these measuring tools and thus enhance its validity and reliability. 33 future research in this field should attempt to identify the most appropriate outcome measurement type and measurement time frames after acl reconstruction. appropriate descriptions of the exercise intervention regimens were presented in the selected studies. this is a positive aspect of the reviewed papers, as a clear description of interventions is often lacking in physiotherapeutic trials. poor descriptions of the interventions make it difficult or impossible to apply effective interventions based on robust research evidence. the exercise interventions applied in the papers were mostly representative of usual clinical practice. 32 the findings of this review are therefore relevant to clinicians who prescribe similar exercise regimens as they provide insight into the effect on patient outcomes. table viii. pain as measured with vas (shaw et al. 34 ) pain at rest pain on performing exercise mean mean intervention control difference intervention control difference mean (sd) mean (sd) (95% ci) mean (sd) mean (sd) (95% ci) day 1 3.1(2.2) 2.6(2) 0.5 6.9(2)* 6(2.1)* 0.9 (-0.3 to 1.3) (0.1 to 1.7) * 2 weeks 2.5(1.7) 2.2(1.9) 0.3 5.9(1.9) 5.2(2.1) 0.7 (-0.4 to 1) (-0.1 to 1.5) 1 month 0.9(0.8) 0.9(1.1) 0 3.5(2) 4(2.3) -0.5 (-0.4 to 0.4) (-1.4 to 0.4) 3 months 0.4(0.7) 0.5(0.7) -0.1 3.1(2) 2.8(2.1) 0.3 (-0.4 to 0.2) (-0.6 to 1.2) 6 months 0.3(0.6) 0.3(0.6) 0 2(1.9) 2.1(1.8) -0.1 (-0.3 to 0.3) (-0.9 to 0.7) *significant results (p<0.05). table ix. pain as measured with ckrs (shaw et al.34) mean a b difference mean (sd) mean (sd) (95% ci) 1 mnth 4.9 (1) 4.8 (1) 0.1 post op (-0.3 to 0.5) 3 mnths 6.1 (1.1) 6.2 (1.2) -0.1 post op (-0.6 to 0.4) 6 mnths 7.5 (1.2)* 6.8 (1.1)* 0.7 post op (0.2 to 1.2)* a = intervention group b = control group * significant results. table x. a-p laxity at 6 months (shaw et al. 34 ) kt-1000 a-p laxity a b p test force number of number of subjects with subjects with laxity (n) laxity (n) 15 lb 3 mm 15 lb 5 mm 0 (47) 2 (44) 20 lb 3 mm 10 (47) 13 (44) 0.36 20 lb 5 mm 1 (47) 7 (44) max manual 3 mm 17 (47) 16 (44) 0.99 max manual 5 mm 1 (47) 9 (44) total number of subjects presenting with lax knees a-p laxity: an anterior-posterior side-to-side difference of greater than 3 mm or greater than 5 mm on testing with the kt-1000 arthrometer. * significant difference (p<0.05) a = intervention group b = control group. 3 (47)* 12 (44)* 0.01* 32* 59* table xi. a-p laxity preoperatively, at 6 months and 24 months follow-up (isberg et al. 15 ) rsa kt-1000 intervention control intervention control median (range) median (range) median (range) median (range) in mm in mm in mm in mm preoperative 8.6 (2.3-15.4) 7.2 (2.2-17.4) 2.0 (0-8.0) 4.0 (0-10.10) 6 mnths 3.4 (0.6-11.5) 3.4 (-3.3 to 7.8) 0 (-3.0 to 1.5) 1.5 (0.5 to 4.5) 24 mnths 2.7 (0-10.7) 2.8 (-1.8 to 9.5) 1.0 (-1.5 to 3.5) 0.5 (-1.0 to 4.0) preop v. 24 mnths a-p laxity: an anterior-posterior side-to-side difference of greater than 3 mm or greater than 5 mm on testing with the kt-1000 arthrometer. = significant difference (p<0.05). p=0.005 p=0.005 p=0.0096 p=0.004 pg4-20.indd 12 4/23/08 11:31:03 am sajsm vol 20 no. 1 2008 13 appropriate function of the quadriceps muscle group is important daily and sporting activities. 27 these review findings indicate that no significant difference in functional performance was noted between the intervention and control group 6 months and 24 months postoperatively. objective functional performance was not assessed before 6 months due to precautionary limitations related to the surgery. there was no difference between groups with respect to most of the subjective functional scale findings. however, a significant difference for the ‘problems with sport category’ was reported by shaw et al., but the effect size indicated that the clinical effect was small. 34 the finding indicated that the intervention group experienced significantly more pain when exercising, and this may contribute further to inhibit quadriceps muscle contraction. 3,34 the improvement in muscle function when performing early quadriceps exercises may thus be relatively small and it appears that functional use of the quadriceps muscle performed when the patient’s pain experience is tolerable may be appropriate to produce appropriate strength required for function. a clinical recommendation may thus be that pain may need consideration when prescribing these exercises. shaw et al. reported that the subjects in the intervention group had marginally better improvement in active knee flexion and extension rom, but this was limited to 1 month postoperatively. 34 however, the effect size indicated a medium clinical effect of range of motion at 1 month. according to milne et al. a minimum of at least 90˚ of flexion is required to safely descend stairs and 105˚ to rise from a toilet seat. 26 however, since both groups achieved these functional range requirements, the clinical effect of the range of motion findings by shaw et al. is questionable. 34 there is concern that early quadriceps exercises may result in increased anterior-posterior knee laxity, resulting in damage to the graft. 15 shaw et al. concluded that the prevalence of knee instability 6 months postoperatively was reduced by performing early quadriceps exercises. 34 however, isberg et al. reported no significant difference between groups 6 months postoperatively. 15 shaw et al. incorporated a larger sample size and may be representative of the acl injury population. 29,34 a more notable finding was that a-p laxity was not different between the intervention and control groups in the long term. 34 this may indicate that early quadriceps exercises can be considered safe in this population as they did not compromise stability. limitations in this review, only studies reported in the english language were considered eligible due to time and resource constraints. in the case of uncertainty regarding information presented in the studies, authors were contacted via e-mail. however, if they did not reply, contact was not made telephonically due to resource constraints. heterogeneity of the data of eligible studies did not allow for a meta-analysis to be conducted. conclusion early quadriceps exercises do not compromise the integrity of the graft, as they do not increase ligament laxity. however, it appears that the gains when performing early quadriceps exercises or restricting quadriceps exercise training to only isometric quadriceps exercises with respect to range of motion and function are small or insignificant. further research is required and should include standardised interventions, measurement time frames and outcome measurement tools to allow for meta-analysis of the data. references 1. andersson c, odensten m, good l, gillquist j. surgical or non-surgical treatment of acute rupture of the anterior cruciate ligament. j bone joint surg 1989; 71(7): 965-74. 2. andersson c, odensten m, gillquist j. knee function after surgical or non-surgical treatment of acute rupture of the anterior cruciate ligament: a randomized study with a long-term follow-up period. clin orthop relat res 1991; 264: 255-63. 3. bajaj p, arendt-nielsen l, andersen ok. facilitation and inhibition of withdrawal reflexes following repetitive stimulation: electroand psychophy siological evidence for activation of noxious inhibitory controls in humans. eur j pain 2004; 9 (1): 25-31. 4. beck pr, 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clin biomech 2002;17: 56-63. 22. linko e, harilainen a, malmivaara a, seitsalo s. surgical versus conservative interventions for anterior cruciate ligament ruptures in adult: review. cochrane database syst rev 2005; issue 2 art. no.:cd001356. doi:10.1002/14641858.cd001356.pub3 23. lobbenhoffer p, tscherne h. rupture of the anterior cruciate ligament. current status on treatment. der unfallchirurg 1993; 96(3):150-68. 24. lloyd-smith w. evidence-based practice and occupational therapy. br j occup ther 1997; 60: 474-8. 25. maher cg, sherrington c, herbert r, moseley a, elkins m. reliability of the pedro scale for rating quality of randomized controlled trials. phys ther 2003; 83: 712-21. pg4-20.indd 13 4/23/08 11:31:05 am 1� sajsm vol 20 no. 1 2008 26. milne s, brosseau l, robinson v, et al. continuous passive motion following total knee arthrosplasty (review). cochrane database syst rev 2003; issue 2. art no.: cd004260. doi: 10.1002/14651858.cd 004260. 27. moore kl, dalley af. clinical oriented anatomy, 4th ed. philadelphia: lippincott, williams and wilkins, 1999; 532. 28. morrissey mc, brewster ce, shields cl jr, brown m. the effects of electrical stimulation on the quadriceps during postoperative knee immobilization. am j sports med 1985;13: 40-5. 29. portney lg, watkins mp. foundations of clinical research: applications to practice, 2nd ed. new jersey: prentice-hall, inc., 2000: 35, 402-3. 30. renstrom p, arms sw, stanwyck ts. strain within the anterior cruciate ligament during hamstring and quadriceps activity. am j sports med 1986; 14: 83-7. 31. roi gs, nanni g, tencone f. time to return to professional soccer matches after acl reconstruction. sport sciences for health 2006; 1: 142-5. 32. shaw t, mcevoy m, mcclelland j. an australian survey of in-patient protocols for quadriceps exercises following anterior cruciate ligament reconstruction. j sci med sport 2002; 5: 291-6. 33. shaw t, williams mt, chipchase ls. a user’s guide to outcome measurement following acl reconstruction. phys ther sport 2004; 5: 57-67. 34. shaw t, williams mt, chipchase ls. do early quadriceps exercises affect the outcome of acl reconstruction? a randomised controlled trial. aust j physiother 2005; 51: 9-17. 35. tay gh, warrier sk, marquis g. indirect patella fractures following acl reconstruction: a review. acta orthopaedica 2006; 77: 494-500. 36. trees ah, howe te, dixon j, white l. exercise for treating isolated anterior cruciate ligament injuries in adults. cochrane database syst rev 2005; issue 4. art. no: cd005316. doi: 10.1002/14651858.cd005316. 37. trees ah, howe te, grant m, gray hg. exercise for treating anterior cruciate ligament injuries in combination with collateral ligament and meniscal damag of the knee in adult: review. cochrane database syst rev 2007; issue 3. art no.:cd005961. doi:10.1002/14651858. cd005961. pub2 38. tyler tf, mchugh mp, gleim gw, nicholas sj. the effect of immediate weightbearing after anterior cruciate ligament reconstruction. clin orthop relat res 1998; 357: 141-8. 39. williams gn, barrance pj, snyder-mackler l, buchanan ts. altered quadriceps control in people with anterior cruciate ligament deficiency. med sci sports exerc 2004; 36: 1089-97. 40. williams gn, buchanan ts, barrance pj, axe mj, snyder-mackler l. quadriceps weakness, atrophy and activation failure in predicted noncopers after anterior cruciate ligament injury. am j sport med 2005; 33: 402-7. 41. woo sl, fow rj, sakane m, livesay ga, rudy tw, fu fh. biomechanics of the acl: measurements of in situ force in the acl and knee kinematics. knee 1998; 5: 267-88. 42. yamamoto y, hsu wh, woo sl, van scyoc ah. knee stability and graft function after anterior cruciate ligament reconstruction: a comparison of lateral and anatomical femoral tunnel placement. am j sport med 2004; 32: 1825-32. introduction anterior knee pain is a common condition that affects a wide age range of patients. 5 the condition is often self-limiting, but can take up to 2 years to resolve. 16 it frequently interferes with exeroriginal research article a conservative programme for treatment of anterior knee pain in adolescents abstract objective. the purpose of this study was to determine the effectiveness of a 2½-week conservative rehabilitation programme in addressing anterior knee pain in adolescents. design. subjects were randomly allocated to a control group (n=12) and an experimental group (n=18). the experimental group was subjected to a 2½-week strength, flexibility and neuromuscular rehabilitation programme. both groups were tested before and after the 2½ weeks and the experimental group also 1 month after the post-test. results. the experimental group reported significant (p<0.01) improvement in pain (visual analogue scale), dis ability (patient-specific functional scale) and condition correspondence: professor mf coetsee university of zululand private bag x1001 kwadlangezwa 3886 tel: 27 35 772-6639 e-mail: mcoetsee@absamail.co.za jacqueline phillips (bsc hons biokinetics) marius f coetsee (phd) department of human movement science, university of zululand, kwadlangezwa (scale for change in condition). the experimental group tested significantly (p<0.01) better for strength (quadriceps and hamstrings), flexibility (quadriceps, hamstrings and gastrocnemius) and neuromuscular control (willknox wobble board and bass test of dynamic balance). the control group experienced no improvement in any of the tests. conclusions. the 2½-week rehabilitation programme for addressing anterior knee pain in adolescents proved to be effective. the study demonstrated good retention of improvements and even further improvement after cessation of the programme. advantages are the short duration and the fact that patients are familiarised with a home programme which they are likely to continue with. although not addressed in this study, literature indicates that restoration of neuromuscular control might be the main contributing factor for the success of the programme. pg4-20.indd 14 4/23/08 11:31:06 am original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the isokinetic rugby union physical work evaluation (rupwe) protocol: can rugby union players meet the physical work demands of the game? jt doran,1 msc (sport science), cscs; r naidoo,2 phd (sport science) 1 just kinetics preventive health care provider, station road, carrigans, lifford, co-donegal, f93vya0, republic of ireland 2 discipline of biokinetics, exercise and leisure sciences, college of health sciences, university of kwazulu-natal, south africa corresponding author: jt doran (jean@justkinetics.com) current occupational health and safety legislation requires the professional rugby union to comply with the mandate to protect employees against occupational diseases and injuries due to workplace hazards and risks, including ergonomic/human risk factors.[1] rugby union-related incidence and risk of injury varies from acute catastrophic/traumatic to chronic degenerative, and severity is dependent on playing position, location, magnitude/load and mechanism of injury.[2-13] the incidence of catastrophic spinal injuries and traumatic brain injuries, such as concussion and chronic traumatic encephalopathy, are potentially hazardous to a player’s career and livelihood in rugby union. the performance of the trunk muscles are not only important to athletic performance in rugby union, but in the prevention of catastrophic injuries to the spine and traumatic brain injuries as experienced on head impact at engagement of the scrum, the collapsing or “popping out” of the scrum or tackle.[2] the evaluation of physical performance’s ability against matching imposed physical demands provides a systematic evidence base to assess match readiness and to modify player development pathways to efficient and safe participation in competitive rugby. professional and novice players of rugby union require a high level of skill, physical tolerance and resistance to fatigue to repeatedly, safely and effectively engage in the match.[2] it is important to understand the physical demands of rugby union[2] with its various implications for coaching, sports medicine, vocational training and occupational health and safety. research limitations in measuring magnitude/load include inconsistency in the units of measurement with little or no consensus in conformity, biomechanical studies attempting to reproduce the aggressive and physical nature of rugby union, and failure to match the imposed physical demands.[2-6, 15, 18, 20-23] the function of the trunk muscle extensors and flexors are to perform and maintain the position of the joints or body posture, provide joint stability, body manoeuvring, locomotive movements through isolated or coupled muscle performance, and to protect the spine against lumbar mechanical stress from excessive forces. significant muscle activity is required to constrain spinal motion in an oppressing environment.[3] muscle balance implies a harmony and synergy between different muscles all working towards the common goal of efficient, effective functional movement. the game of rugby union is dynamic and involves players constantly making postural changes in the match to adapt to game situations. this influences the activation patterns of the trunk muscles in various ways and is dependent upon whether the players are positioned upright, crouching or bending forward in a ruck, maul or scrum, tackling, their speed of movement, and gravity. the trunk extensors (te) and trunk flexors (tf) function during scrummaging is to oppose impact forces, sustain forward movement, maintain and adjust body position and prevent excessive forward flexion or extension, where the scrum will either collapse or “pop out”. hendricks[2] identified that between 2008-2012, the scrum phase accounted for 33% of all catastrophic injuries, reporting 58% as occurring on impact at engagement, 37% from a collapsed scrum and 5% from “popping out”. the acute and chronic front row spinal injury burden of the scrum by region is presented as occurring in the background: to protect the lumbar spine from excessive forces, rugby union players need to demonstrate the work ability of the trunk extensors and flexors to meet the physical demands. aim: to measure and evaluate whether rugby union players were able to meet the imposed physical work demand, considering limitations, tolerances and resistance to fatigue, using isokinetic dynamometry for trunk extensors (te) and trunk flexors (tf). methods: fifty-five male players, between the ages of 18 and 23 years, participated in the study. all participants completed a par-q (pre-activity risk) questionnaire before the isokinetic testing. their height was between 1.80 ± 0.67 m and body mass was 86.0 ± 17.5 kg. participants were subjected to a newly designed protocol using the biodex isokinetic system 3 dynamometer, called the rugby union physical work evaluation (rupwe). results: there was a significant difference between the forwards’ trunk extensor peak torque to body weight 488% ± 119% and the trunk flexor peak torque to body weight 289% ± 73%. furthermore, there was a large effect size between trunk extensor and trunk flexor muscle performance for the forwards (d =2.0) and backs (d =1.9) for peak torque to body weight. spearman’s rank-order correlations (rs) showed a moderate negative correlation for the forwards between trunk extensor peak torque to body weight and time to peak torque, (rs = -0.4; p=0.018). there is a strong negative correlation for the backs between trunk extensor peak torque to body weight and time to peak torque, (rs = -0.6; p=0.003). conclusion: the physical work evaluation protocol can be used as a screening tool for rugby players as it measures the extensive mechanical load placed on the lumbar region. this has the potential to evaluate their athletic performance for the demands of tackling and scrumming. keywords: isokinetic, trunk extensors, trunk flexors, mechanical load, spinal injuries s afr j sports med 2021;33:1-7. doi: 10.17159/2078-516x/2021/v33i1a8686 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a8686 https://orcid.org/0000-0001-9367-8299 https://orcid.org/0000-0002-9664-3734 original research sajsm vol. 33 no. 1 2021 2 cervical (41%), thoracic (56%) and lumbar regions (71%).[4] while it is acknowledged that the risk of injury is multifactorial[3,6-8], the biomechanical or ergonomic demands of rugby union are unique and are likely to significantly contribute to the risk of injury and/or the recurrence of injuries.[2] there has been a proportional increase in the severity of injury and days absent or days lost[7,8] experienced in rugby union, particularly in concussion. studies have shown the enormous mechanical loads imposed upon the lumbar region in rugby union[2-5], hence indicating that trunk muscle performance is undeniably important for athletic performance. to the best of the authors’ knowledge, studies show limited consistency across the measures and units of measurement, nor has any study investigated the involvement of both the trunk extensors and flexors in supporting the spine as co-activators and their combined role in muscle performance in rugby union. while the research does present many studies where electromyography (emg) and maximum voluntary contractions (mvc) are used, which are isometric in nature, very few studies are able to demonstrate a practical evaluation that may be reproduced in exercise, monitored consistently, whilst maintaining validity, reliability and repeatability.[26,12,13,19-22] isokinetic exercise and testing is performed at a pre-set fixed speed allowing for the accommodation of resistance that is equal to the effort applied. the set lever arm’s speed allows the dynamometer to measure the torque output by the participant throughout the range of motion (rom). this is unlike manual muscle or isometric testing, which are static tests, and isotonic testing which measures strength at the strongest section of the rom and is also affected by speed of movement. isokinetic testing provides a safe, objective and reliable evidence base for evaluating muscle performance and determining athletic ability.[9-11] few studies address the differences between forwards and backs in the evaluation of trunk strength and biomechanical studies have focused on either the tackle or the scrum.[26,12,13,15,19-22] thus far, the authors believe that no study has addressed the muscle performance requirements of both the trunk extensors and flexors for the task demands of these two very important tasks to the game of rugby union, and their application to both the forwards and backs at engagement on impact collisions. the need exists to provide rugby union with a gold standard for the evaluation of muscle performance of the trunk flexors and extensors as it applies to the game of rugby union in limiting head impact exposure, catastrophic spinal injuries, and traumatic brain injuries, such as concussion. a further limitation is that most studies involve only a few participants and are focused mainly on the front row or forwards using scrum simulators.[5,12,19-22] although some studies attempt to simulate match conditions, they fail to reproduce the load pattern that is as aggressive and physical in nature as a competitive match.[3] ramesh et al. [3] maintain that spinal moments vary across populations and are dependent on the participant and the scrum. based on the corroboration in the various studies, work ability must be established to measure, at least the very minimum of physical demands that are able to be imposed, while also measuring the participants’ performance abilities, tolerances, limitations and resistance to fatigue[2-5]. using a scrum simulator, milburn[12] found that the physical demand of the engagement phase of the scrum is characterised by a large forward force which lasts approximately one second and acts to stop opposing forward motions. this may be followed by a decrease in force due to the compression of the body tissues and reorientation of body positions. high forces/impulses ranging from 3 740 n for novices and 7 980 n for international players were found, proposing that these were due to their pronounced weight and the high speeds involved, and therefore assumed that this is due mainly to the momentum generated by speed of engagement rather than active muscle action on impact. the average forward impulse per scrum event, being opposed on impact, may range between three to five times the average body mass as determined in the milburn[12] study. therefore, to maintain a neutral spine in order to protect the spine from excessive compressive forces and oppose forward momentum on scrum engagement, the physical demand placed on the te and tf would require an instantaneous activation of these muscles, to produce an opposing force equivalent to between three to five times the player’s own body mass which would then need to be sustained. a maximum voluntary contraction relative to body mass is an important indicator of performance ability for the evaluation of te and tf muscle performance during the demand of the scrum.[12] the voluntary muscle contraction of the te and tf would need to demonstrate the minimum ability to meet this physical demand of 300% relative to body mass. a further indicator of te and tf muscle performance[12] is the instantaneous active muscle action measured in the time taken to attain the maximum voluntary contraction, by measuring the rate of force development. the muscle performance of the te and tf would need to demonstrate the minimum ability to meet this physical demand by attaining the maximum voluntary contraction in <1 000 ms. it is important for the te and tf to instantaneously activate to protect the lumbar spine and the rest of the body from these excessive forces experienced on impact collision during the scrum’s engagement and similarly, in contact during the tackle. in a biomechanical study, hendricks[2] determined the energy/work load generated on magnitude of impact by front on tackles as being 902 j – 7 608 j and the side-on tackle being 595 j – 6 209 j on impact. taking into consideration the need to maintain a neutral spine, the high forces and speed on scrum engagement and the subsequent injuries are due to a lack of optimal muscular balance. therefore, an isokinetic protocol, which is speed and posture/position-dependent, will be able to adequately measure muscle performance, postural balance and stability control by dynamically loading the muscles/joints through their functional range. isokinetic testing is able to provide an insightful, objective, evidentiary basis for assessments and therapeutic interventions through these assessments, and reporting and monitoring that is safe, reliable, valid, practical, meaningful and predictive[9-11]. the use of isokinetic testing as a modality in the evaluation of the ability of physical performance against matched physical demands provides a systematic evidence-base to assess match original research 3 sajsm vol. 33 no. 1 2021 readiness and modify player development and rehabilitation pathways. professional and novice rugby players require a high level of skill, physical tolerance and resistance to fatigue to repeatedly, safely and effectively engage in the demands of the match.[2] the need to measure and evaluate whether rugby union players are able to meet the imposed physical work demand, is warranted. therefore, this study aimed to measure and evaluate whether rugby union players were able to meet the game’s imposed physical work demand, considering limitations, tolerances and resistance to fatigue, using isokinetic dynamometry for te and tf. methods study design this study has a descriptive, cross-sectional design. permission to conduct the study was obtained from the sharks rugby academy, kwazulu-natal, south africa, and ethical clearance was granted from the university’s biomedical research ethics committee (bfc337/19). participants the study was conducted at the sharks rugby academy in durban, kwazulu-natal. fifty-five players were voluntarily recruited to participate in the study. all participants adhered to the following inclusion criteria: injury free, with no acute injury to the spine/lower back for the six weeks previous to the study; nonsymptomatic for lower back pain; healthy with no pre-existing chronic diseases, such as diabetes, heart disease, or injuries. players were excluded if they were currently undergoing rehabilitation for any lumbar injury, or were found to be hypertensive. test procedures and protocol an information session was conducted at the sharks rugby academy prior to testing. the study aim and rugby union physical work evaluation (rupwe) protocol setup (fig. 1) were explained in detail to the participants, informing them of all risks and benefits associated with their participation. informed consent was thereafter obtained from all participants. fifty-five participants completed the par-q and were all eligible to participate in the study. thereafter, height and weight were recorded. participants were instructed on the technique required for trunk extension and flexion. prior to beginning the evaluation, isokinetic machine/ familiarisation was conducted. using the biodex isokinetic system 3 and dual position back attachment, each participant performed the exercise in isokinetic mode, testing the lumbar joint performing extension and flexion. contraction type was set as concentric and speed was set at 10 degrees.s-1 for a single bout of repeated trunk extension and flexion, ending once 6 000 joules of work had been completed (fig. 2). instrumentation height was measured in metres (m) using a stadiometer.[14] weight (kg) was measured using a calibrated scale with a beam and moveable weights.14] isokinetic concentric trunk extension and flexion were measured using a biodex system 3 pro isokinetic system (biodex medical systems, inc., new york, usa). the isokinetic system was calibrated before testing. the participants were requested to be seated at 90 degrees and a range of motion for trunk flexion and extension was set at 70 degrees. axis of rotation used the anterior superior iliac spine. results were measured in newton metres (n·m).[10] the biodex isokinetic system 3 pro is a reliable and valid method for measuring muscle torque recorded during isolated joint exercise when angular velocity remains constant.[9] isokinetic dynamometers provide an accommodating resistance equal and opposite to the muscular forces applied for maximum external force output with changing positions of the joint. the data collection was conducted by a biokineticist, trained in using the isokinetic device. the data were collected in a controlled environment, entered directly into the computer and data station of the isokinetic system. data management the forwards were grouped together as playing positions 1-8 and the backs were grouped together as playing positions 9-15. each participant was allocated a unique code. their codes were entered into the isokinetic computer software system prior to the start of the testing protocol. data were then exported into an excel spreadsheet for statistical analysis. statistical analysis all the data were analysed using the statistical package for the social sciences, version 21. data were quantified using descriptive statistics through means and standard deviations, and the distribution comparing the descriptive results used the wilcoxon signed ranks test and a mann-whitney u-test to investigate the differences between extensors and flexors among the forwards and backs. a binomial test was used to fig. 1. the rupwe protocol setup original research sajsm vol. 33 no. 1 2021 4 investigate the proportion to which the extensors and flexors are able to meet the physical demands of the game. additionally, cohen's d was used to describe the standardised mean difference of an effect. a spearman’s rho (rs) correlation analysis was used to investigate the difference between flexors and extensors among forwards and backs. the level of statistical significance was set at p < 0.05. results fifty-five rugby union participants, aged between 18 and 23 years, were tested; 29 (53%) were forwards and 26 (47%) were backs. their mean height was 1.80 ± 0.67 m and mean body mass was 86.0 ± 17.5 kg). the results for the forwards and backs are presented separately to identify and compare the differences in trunk extension and flexion muscle performance between them. the majority of the tests between the forwards and backs yielded significant differences. mean isokinetic differences are presented in table 1. there were no significant differences in the number of repetitions completed (the mean was 16 ± 4 repetitions); in the range of motion (the mean was 71.6 ± 2.1°); or in the agonist/antagonist ratio, (the mean agonist/antagonist ratio was 63% ± 12% for te and tf between the forwards and the backs). additionally, there were no significant differences for acceleration (the mean te acceleration time was 142 ± 159 ms and mean tf acceleration time was 169 ± 188 ms). there was also no significant difference for deceleration time. the mean te deceleration time was 3 039 ± 3 000 ms and mean tf deceleration time was 2273 ± 2 757 ms. using a binomial test, the te demonstrated a significant 96% ability to match the required minimum physical demands, with p < 0.0005 for peak torque to body weight (%) (pt/bw) > 300%. however, the tf muscles showed no significant difference in proportion to the matching ability required to meet the minimum physical demands of pt/bw % > 300%. the tf muscles had a significant 82% ability to match the required minimum physical demands of time to peak torque (tpt) < 1 000 milliseconds (ms), p < 0.0005. there was a moderate negative correlation for the forwards between trunk extensor pt/bw and tpt, ((rs = -0.4), p = 0.02). there was a strong negative correlation for the backs between trunk extensor pt/bw and tpt, ((rs = -0.6), p = 0.003) (table 2). discussion the study investigated whether the isokinetic te and tf protocol of work ability measures and evaluates rugby union players’ ability to meet the physical work demands for tolerances, limitations and resistance to fatigue imposed by the sport. the slow speed of the protocol at 10 degrees.s-1 produces a load pattern that is both physical and aggressive to simulate the nature of a competitive match. a 90° 90° scrum position is adopted, to isolate the te and tf and minimise force coupling in multi-joint muscle activation and to further increase compressive forces the evaluation is conducted in a seated position. the baseline for the protocol development was created by identifying a minimum work load pattern as observed by hendricks[ 2] and used the magnitude of the sidefig. 2. the rupwe protocol original research 5 sajsm vol. 33 no. 1 2021 on tackle to simulate a maximum work load set at 6 000 j. hendricks[ 2] suggests a theoretical model for the relationship between the number of tackles in which a player engages in acute and chronic fatigue, magnitude of impact (energy load), markers of muscle damage (microtrauma) and how this relationship interacts with the tackle injury risk (tolerance overload and reduction) and tackle performance. quarrie and hopkins[13] determined the number of tackles in a match may range from 10 to 35 tackles and may be dependent on playing position. the protocol allowed for repeated postural change for the duration of the evaluation of forward bending and backward extending, producing dynamic muscle activity and placing extensive mechanical load on the lumbar region. the mean performance of the forwards and the backs for the te demonstrated a significant ability to match the imposed physical demands of work ability for pt/bw. this seems to support the results found in cazzola et al.[18] which identify the preactivation of the erector spinae (es) prior to scrum engagement being >25% mvc; however, in the cazzola study the es significantly reduces during the engagement and sustained phase for the crouch-bind-set (cbs) and crouchtouch-set (cts) procedures of scrum engagement. this could support the milburn[12] study, noting muscle tissue compression and reorientation of body position allowing for compensatory muscle activation, such as the eccentric activation of the tf. the mean performance of the tf for the forwards demonstrated a significant inability to match the imposed physical demands for pt/bw. this may indicate a limitation in the tf to tolerate the normal load of excess energy transferred on the impact of engagement in a single contact of concentric muscle activation.[2-6,13,15] the consequence of this finding supports the potential catastrophic injuries sustained on impact of engagement and the collapsing of the scrum as detected in the hendricks[2] study. however, this could more specifically indicate the limitations in the eccentric muscle activation of the tf during compression of the opposing impact on engagement and the downward forces experienced during the sustained push and reorientation of body positions and the effect of gravity. improving the eccentric strength of the tf could assist in preventing the scrum from collapsing and players from developing catastrophic spinal injuries, traumatic brain injuries or sports-related concussion. this te/tf dynamic muscle strength imbalance suggests that there may be a reduced physiological capacity in the function of the tf to harmoniously synchronise with the te to resist distortion of the muscles and joints when experiencing forces of equal or greater magnitudes, such as observed on the impact of the scrum or impact collisions on contact during the tackle.[2-6, 13,15,16,18] muscle balance implies a harmony and synergy between different muscles, all working towards the common goal of efficient, effective functional movement, which would require concentric and eccentric coactivation of the agonist and antagonist during joint movements. isokinetic eccentric exercise is a practical, safe, effective and efficient way to isolate and condition the tf which would improve the muscle performance to provide the necessary dynamic support as required during the scrum. the higher pt/bw observed for the te may be due to the biomechanical linkages in the skeletal system that, through strain transmission, actively engages proportionally more of the myofascial chain.[15] these authors believe that this may also be as a result of motor pathway development patterns that have been established through traditional methods in coaching, strength and conditioning exercises, such as the deadlift, and specificity of training patterns during coaching sessions, e.g. scrummaging against a scrum machine as observed in the differences of the tf between the forwards and the backs. further investigation into the myofascial chains, combined with traditional strength and conditioning exercises and exacerbated by the specificity of set coaching practices, are more likely to explain the effectiveness of pt/bw development in the te as opposed to the tf. therefore, it is reasonable to assume that the volume of strain transmission and cumulative loading of the mechanoreceptors have contributed to the multifactorial physiological adaptation of the te, as observed in the results of this study. the rationale lends itself to a positive adaptation of the physically imposed demands of training observed in the te pt and pt/bw. as the participants of the study were injury-free, the strain table 1. mean trunk extension and flexion isokinetic results between forwards and backs forwards (n=29) backs (n=26) variable trunk extension trunk flexion cohen’s d p value trunk extension trunk flexion cohen’s d p value peak torque (n·m) 452 ± 128 270 ± 128 1.7 < 0.0005 365 ± 72 237 ± 47 2.1 < 0.0005 peak torque to body weight (%) 488 ± 119 289 ± 73 2.0 < 0.0005 487 ± 115 313 ± 61 1.9 < 0.0005 time to peak torque (ms) 1 411 ± 1 525 772 ± 1 325 0.5 < 0.0005 1 518 ± 1 575 560 ± 642 0.8 < 0.0003 work fatigue (%) 18 ± 13 29 ±13 2.7 < 0.0005 16 ± 14 33 ± 12 3.0 < 0.0005 total work (joules) 4 208 ± 211 1 733 ± 198 -0.1 < 0.0005 4 107 ± 269 1 821 ± 281 -0.5 < 0.0005 position of peak torque (°) 82 ± 19 35 ± 16 12.1 < 0.0005 79 ± 19 33 ± 10 8.3 < 0.0005 coefficient of variance (%) 15 ± 8 16 ± 7 -0.9 16 ± 8 19 ± 8 -1.3 0.028 where applicable data are expressed as mean ± sd table 2. spearman’s rho (rs) between peak torque to body weight (%) and time to peak torque (ms) position trunk extension rs p value trunk flexion rs p value forwards (n=29) -0.4 0.018* -0.5 0.013* backs (n=26) -0.6 0.003** -0.3 0.197 * correlation is significant at the 0.05 level (2-tailed) ** correlation is significant at the 0.01 level (2-tailed) original research sajsm vol. 33 no. 1 2021 6 transmission experienced by the tf in both the forwards and the backs seems to indicate that the loads experienced in strength and conditioning training, or during practice sessions, fails to optimally load the tf.[12] the rationale lends itself to a negative adaptation to physically imposed demands during training. it seems that traditional strength and conditioning/coaching methods are ineffective in matching the dynamic strength produced by the te for the tf. the rate of force development in the te muscle activation sequence for both the forwards and the backs is significantly slower when compared with tf muscle activation. there is a significant inability of the te in both the forwards and the backs to meet the required imposed physical demands for work ability for tpt. this inability, as demonstrated, to match the imposed physical demands for tpt, also indicates an inability to rapidly activate the muscle to produce the maximum dynamic force needed to maintain the structural tensegrity required on impact to tolerate the normal load of excess energy transferred on a single contact.[2-6, 15] impact on engagement is dependent on speed and mass; and in rugby union, the magnitude of impact on engagement has been established as being high.[2-6,15] the player's musculoskeletal system must respond rapidly to provide the necessary structural tensegrity to tolerate the impact experienced on contact engagement. in an unpublished study by pennington[24] investigating neck strength and head acceleration in rugby union, the author demonstrated a correlation between neck muscle strength and head acceleration and determined that neck strength significantly slowed down head acceleration on contact in tackle engagements reducing the risk of concussion and traumatic brain injury. similarly, strengthening the te and tf to respond rapidly to produce maximum voluntary contraction on impact may reduce body and head accelerations minimising the risk of developing catastrophic spinal injuries and or traumatic brain injuries, such as concussion. in this study, both the te and tf demonstrated a deceleration time >1 000 ms. the mean te deceleration time was 3 039 ± 3 000 ms and mean tf deceleration time was 2 273 ± 2 757 ms. the inability to rapidly respond to the opposing impact forces may result in destabilising joint mechanics, altered muscle function, and tissue compression to the point of microtrauma, resulting in tissue and/or motor neuron damage.[2-6,15] fig. 3 illustrates a proposed theoretical model of the compounding effect of macroor microtrauma for repetitive collisions on contact. the results maintain the importance of the rate of force development in te muscle activation in supporting and maintaining trunk stability against posterior and coactivation of tf against anterior lumbar mechanical stress perturbations in rugby union players. the results of the slow rate of force development as demonstrated in both the forwards and the backs may be evidence that the te is predominantly tonic in constitution, and the tf may be more phasic in their constitution. regardless, careful manipulation of exercise could result in adaptation to the te motor neuron, or even conversion of fibre type 1 to fibre type 2.[19] isokinetic exercise at high velocity and in both concentric and eccentric muscle activation patterns would condition the te and tf towards an improved rate of force developments and improve the neuromuscular control of these muscles. the literature on the effects of fatigue in rugby performance seem to present conflicting results.[20-23] the rupwe protocol’s results in this study indicate that the tf is significantly more prone to fatigue, as work fatigue is >25% in both the forwards and backs. though the development of muscle fatigue in this study may not be a reflection of how muscle fatigue manifests during rugby, it does demonstrate significant muscle fatigue experienced during the workload as determined to occur in a single side-on tackle. the te may be more tolerant of, and resistant to, fatigue [20-23] than the tf. the relationship between total work for the te and tf could be improved by careful manipulation of exercise and could result in the adaptation to the motor neurons or muscle type conversion.[19] the relationships between the te and tf as investigated in this study should be central when developing training and or rehabilitation programmes for return to play. conclusion the rupwe protocol determines whether the te and tf are able to meet the physical demands imposed on them by rugby union. rugby union can now use the protocol described in this study as a screening tool that has the ability to safely and objectively predict for injury and improve rehabilitation pathways as it measures the extensive mechanical load placed on the lumbar region. the use of the protocol in combination with the eccentric exercise of the tf could reduce the risk of the scrum collapsing, thereby minimising the incidence of head impact exposure which could result in catastrophic spinal injuries and traumatic brain injuries in sports-related concussion. the protocol establishes a baseline of work ability equivalent to the magnitude or load of a single side-on tackle. therefore, it may be used to identify the limitations in tackle performance by reducing tackle injury risk when considering the number of tackles made in a match. thus the protocol may be used for injury prevention and for evaluating athletic fig. 3. theoretical model describing the aetiology of repetitive collisions on contact in rugby union original research 7 sajsm vol. 33 no. 1 2021 performance in rugby union players. the use of isokinetic exercise in conjunction with the rupwe protocol may assist coaches and medical staff in identifying and rectifying loading conditions to optimally rehabilitate and develop load progressions for return to play and athletic performance development pathways. a coordinated approach to strengthen and prepare a team for all possible scenarios is required. conflict of interest and source of funding: the authors declare no conflict of interest with respect to the authorship and/or publication of this article. research reported in this publication was supported by the fogarty international centre (fic), national institutes of health common fund, office of strategic coordination, office of the director (nih/cf/osc/od), office of aids research, office of the director, nih (oar/od/nih), national institute of mental health of the nih (nimh/nih) under award number d43tw010131. the content is solely the responsibility of the authors and does not necessarily represent the official views of the nih. acknowledgements: the authors would like to acknowledge and thank the participants and staff at the sharks rugby academy, in kwazulu-natal, south africa who willingly participated in this study. author contributions: jtd designed the study, collected the data, analysed and interpreted the data, and wrote the initial draft and final version of the paper. rn contributed to the design of the study, analysed and interpreted the data, critically assessed the initial draft of the paper. both authors approved the final version of the paper. references 1. department of labour occupational health and safety act 1993.government gazette, 27 january 2017 no. 40578. 2. hendricks s, 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[http://dx.doi.org/10.17159/2078-516x/2017/ v29i0a1701] 24. pennington t. the effect of neck strength on head acceleration in rugby union players. masters study unpublished. university of swansea 2020. https://doi.org/10.1080/026404100364974 https://doi.org/10.1016/j.jsams.2011.05.006 https://www.ncbi.nlm.nih.gov/pubmed/?term=schwellnus%20mp%5bauthor%5d&cauthor=true&cauthor_uid=24982503 https://www.ncbi.nlm.nih.gov/pubmed/?term=thomson%20a%5bauthor%5d&cauthor=true&cauthor_uid=24982503 https://www.ncbi.nlm.nih.gov/pubmed/?term=derman%20w%5bauthor%5d&cauthor=true&cauthor_uid=24982503 http://dx.doi.org/10.1136/bjsports-2016-096275 https://doi.org/10.1016/j.ptsp.2014.04.004 https://www.sciencedirect.com/science/journal/10506411 https://doi.org/10.1016/j.jelekin.2014.07.006 https://www.sciencedirect.com/science/article/pii/s0949328x14000453#! https://www.sciencedirect.com/science/article/pii/s0949328x14000453#! https://www.sciencedirect.com/science/article/pii/s0949328x14000453#! https://www.researchgate.net/deref/http%3a%2f%2fdx.doi.org%2f10.1016%2fj.orthtr.2014.02.007 https://www.ncbi.nlm.nih.gov/pubmed/2359151 https://www.ncbi.nlm.nih.gov/pubmed/2359151 https://doi.org/10.1080/02640419008732130 https://doi.org/10.1080/02640419008732130 https://doi.org/10.1177/0363546508316768 https://doi.org/10.1519/jsc.0b013e3181635a6a https://doi.org/10.1136/bjsports-2014-094443 https://doi.org/10.1016/j.apmr.2015.07.023 original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license physical fitness and nutritional anthropometric status of children from disadvantaged communities in the nelson mandela bay region d smith,1 ma; l adams,1 ma; r du randt,1 phd; j degen,2 msc; s gall, 2 phd; n joubert,3, 4 ma; i müller,2,3 phd; s nqweniso,1 ma; u pühse,2 phd; p steinmann,3,4 phd; j utzinger,3,4 phd; c walter,1 phd; m gerber,2 phd 1 department of human movement science, nelson mandela university, port elizabeth, south africa 2 department of sport, exercise and health, university of basel, basel, switzerland 3 swiss tropical and public health institute, basel, switzerland 4 university of basel, basel, switzerland corresponding author: d smith (danielle.smith@mandela.ac.za) globally, an estimated 21% of children under five years old were affected by stunting, while 5.6% of children under five years old were overweight in 2019.[1] in south africa, a noticeable shift from undernutrition to overnutrition is evident with the rapid economic development and the apparent nutrition transition.[2] furthermore, it seems that geographic area may be a potential confounder of malnutrition, as different areas may be at different stages of the nutrition transition.[3] findings from the 2012 south african national health and nutrition examination survey (sanhanes-1)[2] show that the prevalence of overweight and obesity is highest in urban formal and informal areas, while rural informal locality had the highest prevalence of undernutrition. the literature further highlights an inverse association between stunting and socio-economic status (ses), according to the study by meko et al.[3] who found stunting to be associated with low ses groups. malnutrition is of particular concern in low-resourced areas where school tuckshops and vendors outside the school premises offer lowcost food items with little nutritional value.[2] both forms of malnutrition have adverse health effects and the implications are both immediate and long-term. children affected by undernutrition are often at higher risk of infectious communicable diseases and are susceptible to physical and cognitive damage that may affect both school and work performance.[1] overweight and obese children are at an increased risk of non-communicable diseases (ncds), such as type 2 diabetes, later in life.[1] malina et al.[4] noted that for children, the functional consequences of malnutrition extend to daily activities, which require movement proficiency. undernourished children have reduced body size and muscle mass resulting in poorer performance in activities that require muscular strength.[4] meanwhile, overnutrition reduces aerobic capacity and decreases performance in weight-bearing activities.[5] a systematic review by ortega et al.[6] provides compelling evidence about cardiorespiratory fitness (crf) and muscular strength as both physical fitness (pf) components may contribute to the improvement of cardiovascular health in young individuals. furthermore, pf is a powerful marker of health in childhood and adolescence and may be a predictor for adult morbidity and mortality.[6] however, as far as can be ascertained, no studies have investigated the pf status of primary schoolchildren from disadvantaged communities in the nelson mandela bay region in south africa. the main purpose of this paper was to assess the pf and nutritional anthropometric status of grade 4 schoolchildren background: information about the relationships between physical fitness, body composition and nutrition has increased in recent years; however, little is known about physical fitness and the coexistence of under-/overnutrition among children living in disadvantaged areas. objectives: to determine the physical fitness status and its association with body composition, growth and selected sociodemographics in primary schoolchildren from disadvantaged communities in the nelson mandela bay region. methods: nine hundred and sixty-five children (49% girls, m=9.5 years) participated in this cross-sectional study. height and weight were measured to establish body mass index, and height-for-age z-scores. physical fitness was assessed using tests from the eurofit physical fitness test battery (flexibility, upper/lower body muscular strength and cardiorespiratory fitness). betweengroup differences and cross-sectional associations were examined with univariate (chi2-tests, analyses of variance) and multivariate methods (mixed linear/logistic regression). results: most children had normal weight (76.7%), while 4.5% were underweight and 18.7% were overweight/obese. underweight children and children with stunted growth (11.5%) had lower average upper body strength (p<0.001). overweight/obese children had lower scores in weight-bearing activities (p<0.001). children with higher socio-economic status were more likely to be overweight and obese (p<0.001). in the multivariate analyses, sex, age, body mass index, and stunting were associated with children’s physical fitness. conclusion: fitness assessments seem to be a relevant measure of the current health status of children in disadvantaged settings. compared to international norms, the children in this study had relatively low scores for both upperand lower body muscular strength. therefore, effective school-based intervention programmes should be developed to improve children’s physical fitness in disadvantaged schools. keywords: south africa, primary schoolchildren, physical fitness, lower socio-economic status, anthropometry s afr j sports med 2020;32:1-8. doi: 10.17159/2078-516x/2020/v32i1a8158 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8158 https://orcid.org/0000-0002-6920-981x https://orcid.org/0000-0002-7374-9034 https://orcid.org/0000-0003-1459-1916 https://orcid.org/0000-0001-6617-4343 https://orcid.org/0000-0002-6397-9979 https://orcid.org/0000-0001-8793-9624 https://orcid.org/0000-0001-6140-8948 https://orcid.org/0000-0002-0644-3609 https://orcid.org/0000-0003-1033-9908 https://orcid.org/0000-0001-6885-0798 https://orcid.org/0000-0003-4800-3019 https://orcid.org/0000-0003-1228-316x https://orcid.org/0000-0001-8422-4105 original research sajsm vol. 32 no. 1 2020 2 from disadvantaged communities in the nelson mandela bay region. moreover, this study’s goal was to determine the association of pf with selected demographics, such as age, sex, and ses. in previous research, pf has been associated with age, gender and ses. [7-8] therefore, this study aimed to determine the association of pf with these selected demographics within this studied population. methods study design data presented here were collected in the framework of the disease, activity and schoolchildren’s health (dash) study.[9] for the purpose of this paper, a cross-sectional analysis was conducted of the baseline data collected between february and march 2015. participants the project information was delivered to 103 quintile three government (public) primary schools situated in historically disadvantaged areas of the nelson mandela bay region of south africa. in south africa, public schools are classified into five quintiles. quintile one is the poorest, while quintile five is the least well-off group.[10] the quintile system is linked to the allocation of funds which is determined by the poverty of the community surrounding the school. eight schools (and 26 classes) were selected, based on the dash study criteria (at least 100 learners in grade 4, geographical location equal number of schools from northern areas and townships, population demographics similar number of xhosa-, afrikaansand english-speaking schoolchildren), and their willingness to participate. consent forms were distributed to 1154 children: 145 parents did not consent, resulting in 1009 study participants. children were informed about the study and provided verbal assent. in total, 965 children met the further inclusion criteria and were considered for the present data analyses. as shown in table 1, the number of missing values varied across the different indicators. in total, 838 children had complete data on all variables that were used in the present paper. ethical considerations the dash study obtained ethical approval from the ethics committee of northwest and central switzerland (eknz; 2014–179), the nelson mandela university research ethics committee (human) (h14-hea-hms-002), the eastern cape department of health and the eastern cape department of education. measures the components measured to address the primary focus of this paper are pf, socio-demographic background, and anthropometry. pf was assessed using the eurofit physical fitness test battery. body weight was measured once to the nearest 0.1 kg (micro t7e electronic platform scale, optima electronics; george, south africa). height was assessed to the nearest 0.1 cm (surgical sa; johannesburg, south africa). body weight and height values were used to calculate body mass index (bmi), in which ageand sexspecific cut-offs were applied to determine the prevalence of underweight and overweight/obesity.[11-12] height values were used to determine height-for-age z-scores (haz) according to the world health organization’s (who) growth standards, and sex-adjusted haz scores were used as an indicator for stunting.[13] crf was assessed using the 20 m shuttle run test, adhering to the protocol by léger.[14] the number of fully completed laps was recorded when the learner failed to reach the 20 m turn-line on two consecutive intervals. the number of laps was used to calculate the estimated vo2max (adjusted for age and sex). upper body muscular strength was measured by the grip strength test using the saehan hydraulic hand dynamometer (msd europe bvba; tisselt, belgium). three alternate trials were recorded using a hand dynamometer and averaged. lower body muscular strength was assessed with the standing broad jump test. the longest of two trial jumps (to the nearest 1 cm) was recorded as the final score. the sit and reach test was used to measure flexibility. the better of two trials (to the nearest 0.1 cm) was recorded as the final score. a detailed description of the procedures can be found in the dash study protocol.[9] to estimate ses, learners completed a 9-item questionnaire pertaining to durable household asset ownership (e.g. refrigerator) and housing characteristics (e.g. number of bedrooms).[15] a score was calculated based on the dichotomised items (0=not available; 1=available).[16] the items were coded and summarised to build an overall index ranging between 0 and 9. the scores (0-7) represent the lower third of all ses scores and scores (8-9) represents the upper two-thirds of the sample. a principal component analysis with varimax rotation showed that all assessed items loaded reasonably well on the underlying factor (all factor loadings higher than 0.33, 43.3% of explained variance). moreover, the internal consistency of the ses index was good (cronbach’s alpha = 0.82). statistical analyses quality control ensured the confidentiality, accuracy and completeness of data. the collected data were double-entered and validated in epidata version 3.1 (epidata association; odense, denmark). descriptive statistics and associations were calculated using spss version 26 (ibm; armonk, usa). to examine differences with regard to age, sex, and ses, a series of univariate analyses of variance (anovas) were carried out, with social and demographic background variables as fixed factors. pf and anthropometric measures as dependent variables. 2-tests were performed to examine whether younger vs. older children, boys vs. girls and children with higher vs. lower ses were over-/underrepresented among children who were classified as underweight, overweight/obese or as being stunted. to examine whether children classified as underweight, normal weight or overweight/obese differ from each other with regard to pf, the authors carried out a further series of anovas. since most children were normal weight and not stunted (see below), welch tests were used to account for unequal group sizes. finally, the same procedures were used to examine differences between children classified as stunted vs. not stunted. bonferroni post-hoc tests were used if more than two groups original research 3 sajsm vol. 32 no. 1 2020 were compared. to interpret effect sizes, cohen’s[17] recommendations were followed: 2  0.01 (small effect), 2  0.059 (moderate effect), 2  0.138 (large effect). finally, to take into account the nested and multivariate nature of the data (students assessed in classes, which are part of schools; interrelatedness between assessed independent variables), mixed linear and mixed logistic regression analyses were performed with random intercepts for school classes. more specifically, sex, age, ses, bmi, and stunting were used to determine the multivariate association with the pf indicators (linear models). moreover, sex, age, ses, and the pf indicators were used to explain the children’s nutritional status and stunting (logistic models). for mixed linear/logistic regression analyses, the unstandardised b coefficients are provided in combination with the 95% confidence intervals (ci). across all analyses, the statistical significance was set at p<0.05. results descriptive statistics for the total sample are presented in table 1. the mean age of the children was 9.5 years (sd=1.0), and the sex distribution was similar (48.4% girls, 51.6% boys). moreover, the study sample was relatively homogeneous with regard to ses. table 1 also shows that the majority of the children had normal weight (76.8%), whereas 4.5% were underweight and 18.7% were categorised as overweight/ table 2. medians and 25th/75th percentiles (quartiles) of grip strength, standing broad jump, flexibility and vo2max for quintile three primary schoolchildren in the nelson mandela bay region grip strength (kg) standing broad jump (cm) flexibility (cm) crf (vo2max, ml-1kg-1min-1) sex age n median quartiles median quartiles median quartiles median quartiles boys 8 38 11.3 10.1; 13.0 130.0 122.0; 136.0 33.3 30.0; 35.6 51.9 49.7; 56.4 9 188 12.0 10.2; 13.8 129.0 116.0; 139.0 29.9 29.9; 34.3 50.3 48.0; 54.9 10 161 13.2 10.8; 14.8 133.5 119.8; 147.0 29.3 25.3; 33.3 51.1 46.3; 53.5 11 78 14.4 11.8; 16.2 134.0 123.5; 149.0 28.8 25.2; 33.6 52.0 47.0; 54.4 12 19 13.5 10.7; 15.2 135.0 119.5; 148.0 27.6 24.0; 31.9 50.5 46.4; 53.7 girls 8 66 10.5 9.2; 12.4 114.5 101.3; 125.0 34.9 30.0; 38.4 47.5 47.5; 49.7 9 244 10.7 10.7; 12.3 117.0 106.0; 128.0 33.1 29.4; 33.1 48.0 45.7; 48.0 10 113 11.7 9.8; 14.3 122.0 109.0; 133.5 33.8 29.4; 37.1 46.3 43.9; 48.7 11 35 12.9 10.9; 14.7 121.0 101.8; 132.5 31.5 27.7; 35.6 44.6 42.1; 47.0 12 9 14.3 12.1; 15.3 120.0 110.5; 127.0 31.6 24.4; 34.3 42.9 38.3; 47.9 table 1. descriptive statistics of all study variables, for the total sample (n=965) of quintile three primary schoolchildren in the nelson mandela bay region social and demographic background n % sex girls 467 48.4 boys 498 51.6 n mean sd min max age (years) 965 9.5 1.0 8.0 15.0 socio-economic status (0-9) 957 7.5 2.1 0.0 9.0 anthropometrics n mean sd min max height (cm) 960 133.2 7.1 109.2 165.3 weight (kg) 960 30.5 7.6 15.8 87.4 bmi (kg/m2) 960 17.0 3.0 11.5 41.7 bmi-for-age n % underweight 43 4.5 normal weight 737 76.8 overweight 125 13.0 obese 55 5.7 anthropometric status n mean sd min max haz 960 -0.8 1.1 -4.7 3.1 stunting n % not stunted 850 88.5 stunted 110 11.5 physical fitness n mean sd min max flexibility (cm) 895 31.3 5.9 9.1 47.6 upper body muscular strength (kg) 895 12.1 3.1 2.8 25.2 lower body muscular strength (cm) 891 123.8 19.7 39.0 181.0 crf (vo2max, ml-1kg-1min-1) 874 49.1 4.3 32.3 61.9 the different number of children per variable are due to different number of missing values for different variables. bmi, body mass index; haz, height for age; crf, cardiorespiratory fitness. original research sajsm vol. 32 no. 1 2020 4 obese. moreover, approximately one in nine children (11.5%) was stunted. table 1 also summarised the mean scores for all fitness indicators, whereas table 2 depicts the 50th percentile (p50) scores and the interquartile ranges per sex and age for all fitness indicators. table 3 summarises the results of the univariate statistical analyses. younger children were more flexible and had higher vo2max values, whereas older children performed significantly better in upperand lower muscular strength tests. a 2-test showed that children with underweight, normal weight and overweight/obesity were similarly distributed among younger and older children. by contrast, older children (19.2%) had a higher risk of being stunted than younger children (5.7%), 2(1,958)=642.1, p<0.001. sex-specific differences became apparent with boys outperforming girls in the vo2max and muscular strength tests. girls presented with significantly higher flexibility and bmi values. a chi2-test, 2(2,958)=6.1, p<0.05 indicated that, compared to boys (15.8%), girls were more likely to be classified as overweight/obese (22.0%). by contrast, no significant sex differences were found for stunting. in terms of ses, children with higher ses had significantly table 3. comparison of physical fitness parameters, based on children’s age, sex and socio-economic status amongst the study population from quintile three primary schools in the nelson mandela bay region age 8-9 years (n=550) 10-15 years (n=415) mean sd mean sd f p 2 flexibility (cm) 31.9 5.7 30.3 6.2 16.3 <0.001 0.018 upper body muscular strength (kg) 11.3 2.8 13.1 3.2 79.9 <0.001 0.082 lower body muscular strength (cm) 120.6 19.0 128.2 19.9 33.4 <0.001 0.036 crf (vo2 max, ml-1kg-1min-1) 49.4 3.9 48.8 4.8 4.2 0.042 0.005 bmi (kg/m2) 17.0 3.0 17.0 3.0 0.0 0.994 0.000 sex boys (n=498) girls (n=467) mean sd mean sd f p 2 flexibility (cm) 29.7 5.8 32.9 5.6 73.5 <0.001 0.076 upper body muscular strength (kg) 12.8 3.1 11.3 2.9 52.1 <0.001 0.055 lower body muscular strength (cm) 130.6 19.1 116.8 17.8 123.3 <0.001 0.122 crf (vo2 max, ml-1kg-1min-1) 50.9 4.4 47.4 3.4 174.6 <0.001 0.167 bmi (kg/m2) 16.8 2.7 17.2 3.3 4.0 0.046 0.004 socio-economic status (ses) lower ses (0-7) (n=317) higher ses (8-9) (n=640) mean sd mean sd f p 2 flexibility (cm) 31.1 5.8 31.4 6.0 0.5 0.502 0.001 upper body muscular strength (kg) 11.4 2.9 12.4 3.1 18.4 <0.001 0.020 lower body muscular strength (cm) 125.0 17.6 123.4 20.7 1.2 0.269 0.001 crf (vo2 max, ml-1kg-1min-1) 49.0 4.4 49.2 4.2 0.5 0.468 0.001 bmi (kg/m2) 16.4 2.7 17.3 3.1 21.2 <0.001 0.022 crf, cardiorespiratory fitness; bmi, body mass index table 4. comparison of fitness parameters among children who are underweight, normal weight and overweight/obese, or stunted versus not stunted, attending quintile three primary schools in the nelson mandela bay region underweight (1) normal weight (2) overweight/ obesity (3) welch-test bonferroni post-hoc comparison mean sd mean sd mean sd f p 2 1-2 1-3 2-3 flexibility (cm) 30.4 5.9 31.1 6.0 32.2 5.8 2.6 0.075 0.006 1.00 0.283 0.115 upper-body muscular strength (kg) 9.8 2.6 11.8 2.9 13.5 3.4 29.2 <0.001 0.065 <0.001 <0.001 <0.001 lower-body muscular strength (cm) 125.5 19.8 126.7 18.6 111.6 19.9 39.3 <0.001 0.089 1.00 <0.001 <0.001 crf (vo2max, ml-1kg-1min-1) 49.1 4.0 49.7 4.3 47.0 3.8 31.6 <0.001 0.060 1.00 0.012 <0.001 not stunted stunted welch-test mean sd mean sd f p 2 flexibility (cm) 31.3 6.0 31.4 5.9 0.0 0.867 0.000 upper-body muscular strength (kg) 12.3 3.1 10.3 2.6 48.9 <0.001 0.041 lower-body muscular strength (cm) 123.8 20.3 123.7 15.4 0.0 0.929 0.000 crf (vo2max, ml-1kg-1min-1) 49.2 4.2 49.0 4.9 0.2 0.615 0.000 crf, cardiorespiratory fitness original research 5 sajsm vol. 32 no. 1 2020 higher upper-body muscle strength and significantly higher bmi values. in line with this, children with higher ses scores were overrepresented among overweight/obese children (22.4%) compared to their peers with lower ses scores (11.4%), 2(2,948)=26.6, p<0.001. by contrast, children with lower ses scores had a higher risk (19.0%) of being stunted, compared to their peers with higher ses scores (7.9%), 2(1,948)=25.5, p<0.001. table 4 shows that children with varying anthropometric nutritional status differed significantly in the muscular strength and crf tests. the highest grip strength was observed in children classified as overweight/obese, whereas underweight children had the lowest grip strength. by contrast, overweight children performed significantly worse than their underweight and normal weight peers in the lower body strength and crf tests. children classified as stunted had significantly lower upper body muscular strength than their non-stunted peers. none of the other fitness indicators differed between stunted and non-stunted children. the findings of the multivariate analyses are summarised in tables 5 and 6. table 5 shows that girls, younger age and being stunted were associated with better flexibility. higher upper body muscular strength was associated with boys, older age, higher bmi and being not stunted. higher scores on lower body muscular strength was associated with boys, older age, lower bmi and being not stunted. finally, higher crf was linked to boys, younger age, and lower bmi. in the multivariate analyses, ses was not associated with any of the fitness indicators. table 6 shows that older children were more likely to be classified as stunted in the multivariate analyses. furthermore, after controlling for all other variables, low scores for upper body muscular strength were significantly associated with stunting, whereas no significant association was found with lower body muscular strength and crf. table 6 further shows that older peers and children with low upper body muscular strength were more likely to be classified as underweight than normal weight. moreover, younger children and children with higher upper body and low lower body muscular strength were more likely to be classified as overweight/obese than normal weight. the same also applied for children with lower vo2max scores. discussion in this study, the authors identified the fitness status of primary schoolchildren, examined the association of pf with selected demographics, and investigated the relationship between pf and anthropometric nutritional status. the key findings are that pf indices are associated with children’s social and demographic background. however, children’s sex and age were more closely associated with their pf than their socioeconomic background. moreover, children with lower upper body muscular strength are more likely to be classified as stunted or underweight, whereas children with high upper body muscular strength, low lower body muscular strength, and lower crf scores are more likely to be classified as overweight/obese. the results of the multivariate analyses show that higher flexibility was associated with stunting; however, these findings differ from those in armstrong et al.[5] who reported table 5. association between physical fitness indices as well as sociodemographic background variables and anthropometric nutritional status among children attending quintile three primary schools in the nelson mandela bay region physical fitness indices flexibility (cm) upper body muscular strength (kg) lower body muscular strength (cm) cfr (vo2max, ml-1kg-1min-1) b estimate (95% ci) p b estimate (95% ci) p b estimate (95% ci) p b estimate (95% ci) p sex girls (reference) — — — — boys -3.02 -3.76; -2.28 <0.001 1.22 0.88; 1.56 <0.001 11.51 9.14; 13.88 <0.001 3.66 3.17; 4.16 <0.001 age (years) -0.57 -0.99; -0.14 <0.001 1.19 1.00; 1.38 <0.001 2.98 1.64; 4.31 <0.001 -0.93 -1.21; -0.65 <0.001 socio-economic status (0-9) -0.09 -0.28; 0.10 0.341 0.08 -0.01; 0.16 0.084 0.27 -0.33; 0.86 0.377 -0.05 -0.18; 0.07 0.429 bmi (kg/m2) 0.01 -0.11; 0.14 0.835 0.33 0.27; 0.39 <0.001 -2.02 -2.42; -1.61 <0.001 -0.45 -0.54; -0.37 <0.001 stunting stunted (reference) — — — — not stunted -1.44 -2.66; -0.22 0.021 1.92 1.36; 2.47 <0.001 5.61 1.70; 9.51 0.005 0.01 -0.80; 0.82 0.976 overall model information corrected model: f(5,873)=17.6, p<0.001 constant term: b=40.1, estimate (95% ci): 35.0; 45.2, t=15.6, p<0.001 corrected model: f(5,873)=81.6, p<0.001 constant term: b=-7.8, estimate (95% ci): -10.1, -5.5 t=-6.7, p<0.001 corrected model: f(5,869)=48.5, p<0.001 constant term: b=116.9, estimate (95% ci): 10.9; 132.8, t=14.4, p<0.001 corrected model: f(5,852)=73.6, p<0.001 constant term: b=64.2, estimate (95% ci): 60.8; 67.5, t=37.7, p<0.001 in the mixed linear regression models, cases were excluded listwise from the analysis if they had missing data in one or several of the covariates or in the dependent variables. therefore, the analyses were based on the following number of students: flexibility: n=879; upper body muscular st rength: n=879; lower body muscular strength: n=875; cardiorespiratory fitness: n=858. b is the adjusted unstandardized estimate of the beta coefficient. estimate (95% ci) is the adjusted unstandardized beta coefficients, 95% confidence interval. all p-values are calculated using mixed linear regression, adjusting for clustering of school classes. cfr, cardiorespiratory fitness; bmi, body mass index original research sajsm vol. 32 no. 1 2020 6 similar sit-and-reach values regardless of nutritional status. using the who classification for stunting (z<-2),[13] children with stunted growth had significantly lower grip strength; the difference was of moderate magnitude (4.2% of explained variance). this may be due to reduced muscle mass, body size and a deficiency in muscle tissue needed to generate force as a result of early undernutrition.[4] similar observations were reported in a south african study covering five provinces (western cape, eastern cape, gauteng, kwazulu-natal and the free state) where stunted children performed worse than normal weight children in four out of five fitness tests.[5] the findings of the multivariate analyses also showed that overweight/obese children presented with significantly higher grip strength values than underweight and normal weight children. this corresponds with the results found in malina et al.[4] who reported higher grip strength scores in overweight/obese children, but when grip strength was expressed per unit body mass, then strength was significantly lower in overweight/obese children in comparison to normal weight and stunted children. this confirms that weight has a strong association with grip strength among children. it may be further deduced that the increased grip strength of children with higher ses may be the result of their higher body mass, and thus also higher (absolute, but not relative) muscle mass, since total strength is associated with body mass.[18] this is reflected in the fact that ses was no longer associated with grip strength in the multivariate analyses. moreover, the univariate analyses in this study identified a nutritional deficiency with ses as children with low ses were at a higher risk of stunting.[3] this is in line with results reported by meko et al.[3] who confirmed that determining factors for stunting are mainly household food insecurity, low parent education and low employment levels. it is, however, noteworthy that the influence of ses was not apparent in the multivariate analyses, after controlling for other socio-demographic factors and pf indices. as expected, overweight/obese children performed significantly worse than their underweight and normal weight peers in weight-bearing activities such as the 20 m shuttle run test. this aligns with previous studies which confirm the relationship between the standing broad jump, the 20 m shuttle run and bmi: a higher proportional body mass is associated with lower performance.[18] this study’s results show significant differences in lower body strength and crf between boys and girls, which may be explained by physiological and anatomical differences. finally, if compared table 6. associations between anthropometric nutritional status as well as socio-demographic background variables and physical fitness indices among children attending quintile three primary schools in the nelson mandela bay region mixed logistic (binary) regression analysis mixed logistic (multinomial) regression analysis stunted vs. not stunted (reference category) underweight vs. normal weight (reference category) overweight/obese vs. normal weight (reference category) b estimate (95% ci) p b estimate (95% ci) p b estimate (95% ci) p sex girls (reference) — — — boys 0.26 -0.35; 0.87 0.405 -0.42 -1.30; 0.47 0.357 0.55 0.04; 1.05 0.034 age (years) 1.37 1.02; 1.72 <0.001 0.74 0.32; 1.15 <0.001 -0.91 -1.22; -0.60 <0.001 socio-economic status (0-9) -0.05 -0.17; 0.56 0.332 -0.07 -0.22; 0.09 0.414 0.07 -0.06; 0.19 0.286 bmi overweight/obese (reference) — — — normal weight 1.55 0.05; 3.04 0.042 — — — — — — underweight 1.56 -0.17; 3.29 0.078 — — — — — — stunting stunted (reference) — — — not stunted — — — -0.25 -1.12; 0.62 0.577 1.20 -0.28; 2.68 0.111 flexibility (cm) 0.08 0.03; 0.13 0.002 -0.02 -0.08; 0.05 0.600 0.04 0.00; 0.08 0.035 upper-body muscular strength (kg) -0.44 -0.56; -0.31 <0.001 -0.37 -0.54; -0.20 <0.001 0.32 0.24; 0.40 <0.001 lower-body muscular strength (cm) -0.01 -0.03; 0.01 0.297 0.01 -0.01; 0.04 0.295 -0.04 -0.05; -0.03 <0.001 crf (vo2max, ml-1kg-1min-1) 0.05 -0.02; 0.11 0.190 0.03 -0.07; 0.12 0.590 -0.21 -0.29; -0.15 <0.001 overall model information corrected model: f(9,820)=9.9, p<0.001 constant term: b=-15.4, estimate (95% ci): -20.6; -10.2, t=-5.8, p<0.001 corrected model: f(16,820)=10.1, p<0.001. normal vs. overweight: constant term: b=-7.6, estimate (95% ci): -14.9; -0.3, t=-2.0, p=0.042. normal vs. overweight: constant term: b=14.6, estimate (95% ci): 9.2; 20.0, t=5.3, p<0.001 in the mixed logistic regression models, cases were excluded listwise from the analysis if they had missing data in one or se veral of the covariates or in the dependent variables. therefore, the analyses were based on the following number of students: stunting: n=838, bmi status: n=838 . b is the adjusted unstandardized estimate of the beta coefficient. estimate (95% ci) are the unstandardized beta coefficients, 95% confidence interval. all p-values are calculated using mixed linear regression, adjusting for clustering of school classes. cfr, cardiorespiratory fitness; bmi, body mass index original research 7 sajsm vol. 32 no. 1 2020 to international norms derived from tests with european[19] and australian children,[20] children of the present sample had lower scores for grip strength and standing broad jump, while flexibility and vo2max scores were seemingly higher. the low scores in the grip strength and broad jump tests are important because muscular strength proved to be an important health indicator in previous research among children, adolescents and adults.[6,21] for instance, the systematic review by volaklis et al.[21] reports on the protective role of muscular strength as a modifiable risk factor, as the literature highlights an inverse relationship between muscular strength with all-cause mortality. therefore, reduced muscular strength performance not only affects functional movement proficiency,[4] but poor muscle strength associated with undernutrition may also increase the risk of metabolic diseases such as lipid disorders and type 2 diabetes.[21] the fact that age and sex were more closely associated with children’s pf than ses may be attributable to the fact that this study’s sample was relatively homogenous in terms of the latter variable. the strengths of this study are the large sample size, the focus on children from disadvantaged schools, and the large battery of standardised and internationally acknowledged tests. the analyses in this study also went beyond testing univariate relationships and accounted for potential confounders and the nested nature of the data. it can also be assumed that multicollinearity was not an issue in the present analyses, as the highest bivariate correlations between dependent variables was only r=0.42, p<0.001 (between vo2max and lower body muscular strength). moreover, all variance inflation factor (vif) scores were low (<1.53). nevertheless, the authors did experience some shortcomings during field testing. for instance, as a self-report measure completed by the children themselves, the ses estimation did have an element of subjectivity. an alternative would have been to assess ses via a parent survey or by using more traditional indicators (such as household income or parental occupation).[22] however, it should be noted that ownership of durable assets, as well as characteristics of housing infrastructure and conditions have been used previously to correctly assess family ses.[15] importantly, previous studies also showed that children’s self-reports can be used to assess wealth, and that such instruments are able to detect health inequalities across a wide range of different indicators.[23] furthermore, it is also important to make reference to the testing conditions (e.g. weather, clothing and footwear worn by the children and ground surfaces at the schools), all of which are considered to be limitations that this study had restricted control over. finally, the focus of this study was on children attending disadvantaged schools. thus, only limited generalisation is possible for children from more advantaged school settings. conclusion fitness assessments seem to be a relevant measure of the current health status of children in disadvantaged settings. compared to international norms, the children from disadvantaged schools of this study had relatively low scores for both upperand lower body muscular strength. therefore, further research and effective school-based intervention programmes should be developed to improve children’s pf in disadvantaged schools. conflict of interest and source of funding: this study was supported by the swiss national science foundation (bern, switzerland; project no. izlsz3 149015) and the national research foundation of south africa africa (pretoria, south africa; project no. 87397) through a swiss-south african joint research project. the funders had no role in the study design, data collection and analysis, decision to publish, or preparation of this manuscript. the authors declare no conflict of interest. author contributions: ds; data collection, conception, design, analysis, and interpretation of data, and writing up the manuscript. la; data collection and critical revision for important intellectual content; approval of the version to be published. rdr; critical revision for important intellectual content; approval of the version to be published. jd; data collection and critical revision for important intellectual content; approval of the version to be published. sg; data collection and critical revision for important intellectual content; approval of the version to be published. nj; data collection and critical revision for important intellectual content; approval of the version to be published. im; conception, and design of the research, data collection, and critical revision for important intellectual content; approval of the version to be published. sn; data collection and critical revision for important intellectual content; approval of the version to be published. up; critical revision for important intellectual content; approval of the version to be published. ps; critical revision for important intellectual content; approval of the version to be published. ju; critical revision for important intellectual content; approval of the version to be published. cw; critical revision for important intellectual content; approval of the version to be published. mg; conception, and design of the research, analysis, and interpretation of data, critical revision for important intellectual content, and approval of the version to be published. references 1. united nations children’s fund (unicef)/world bank group. levels and trends in child malnutrition: key findings of the 2020 edition of the joint child malnutrition estimates. geneva: world health organization, 2020. available at: https://www.who.int/publications/i/item/jme-2020 edition 2. shisana o, labadarios d, rehle t, et al. the south african national health and nutrition examination survey, 2012: sanhanes-1. cape town: hsrc press. 423p. 3. meko ln, slabber-stretch m, walsh cm, et al. school environment, socioeconomic status and weight of children in bloemfontein, south africa. afr j prim health care fam med 2015;7(1):a751. [doi:10.4102/phcfm.v7i1.751][pmid: 26245592] 4. malina rm, reyes mp, tan sk, et al. physical fitness of normal, stunted and overweight children 6–13 years in oaxaca, mexico. eur j of clin nutr 2011;65(7):826-834. [doi:10.1038/ejcn.2011.44][pmid: 21448221] 5. armstrong me, lambert mi, lambert ev. relationships https://www.who.int/publications/i/item/jme-2020 http://dx.doi.org/10.4102/phcfm.v7i1.751 original research sajsm vol. 32 no. 1 2020 8 between different nutritional anthropometric statuses and health-related fitness of south african primary school children. ann hum biol 2017;44(3):208-213. [doi:10.1080/03014460.2016.1224386][pmid: 27546583] 6. ortega fb, ruiz jr, castillo mj, et al. physical fitness in childhood and adolescence: a powerful marker of health. int j obes (london) 2008;32(1):1-11. 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[doi:10.1186/s12889-015-2636-y] 10. south africa. department of education. south africa schools act (84/1996): amended national norms and standards for school funding. government gazette 2006;494 (29179): 1-55 11. cole tj, bellizzi mc, flegal km, et al. establishing a standard definition for child overweight and obesity worldwide: international survey. bmj 2000;320(7244):1240-1243. [doi:10.1136/bmj.320.7244.1240][pmid: 10797032] 12. cole tj, flegal km, nicholls d, et al. body mass index cut offs to define thinness in children and adolescents. bmj 2007; 335(7612):166-167. [doi:10.1136/bmj.39238. 43918.80][pmid: 176556507] 13. de onis m, onyango aw, borghi e,et al. development of a who growth reference for school-aged children and adolescents. bull world health organ 2007; 85(9):660–667. [doi:10.2471/blt.07.043497] [pmid: 18026621] 14. léger la, mercier d, gadoury c, et al. the multistage 20 metre shuttle run test for aerobic fitness. j sports sci 1988;6(2):93–101. [doi:10.1080/02640418808729800] [pmid: 3184250] 15. filmer d, pritchett lh. estimating wealth effects without expenditure data—or tears: an application to educational enrollments in states of india. demography 2001;38(1):115-132. [doi:10.1353/dem.2001.003][pmid: 11227840]] 16. salvini m, gall s, müller i, et al. physical activity and healthrelated quality of life among schoolchildren from disadvantaged neighbourhoods in port elizabeth, south africa. qual life res 2018;27(1):205-216. [doi.10.1007/s11136017-1707-1][pmid: 28965191] 17. cohen j. statistical power analysis for behavioural sciences. 2nd ed. hillsdale, new jersey: lawrence erlbaum associates; 1988. 18. ploegmakers jj, geertzen jh, bulstra s,. grip strength is strongly associated with height, weight and gender in childhood: a cross-sectional study of 2241 children and adolescents providing reference values. j physiother 2013; 59(4): 255-261. [doi: 10.1016/s1836-9553(13)70202-9][pmid: 24287219] 19. tomkinson gr, lang jj, tremblay ms, et al. international normative 20 m shuttle run values from 1 142 026 children and youth representing 50 countries. br j sports med 2017;51(21):1545-1554. [doi:10.1136/bjsports-2016-095987] [pmid:27208067] 20. catley mj, tomkinson gr. normative health-related fitness values for children: analysis of 85347 test results on 9–17-yearold australians since 1985. br j sports med 2013;47(2):98-108. [doi:10.1136/bjsports-2011-090218][pmid: 22021354] 21. volaklis ka, halle m, meisinger c. muscular strength as a strong predictor of mortality: a narrative review. eur j intern med 2015;26(5):303-310. [doi:10.1016/j.ejim.2015.04.013][pmid: 25921473] 22. currie ce, elton ra, todd j, et al. indicators of socioeconomic status for adolescents: the who health behaviour in schoolaged children survey. health educ res 1997;12(3):385-397. [doi:10.1093/her/12.3.385][pmid: 10174221] 23. currie c, molcho m, boyce w, et al. researching health inequalities in adolescents: the development of the health behaviour in school-aged children (hbsc) family affluence scale. soc sci med 2008;66(6):1429-1436. [doi:10.1016/j.socscimed.2007.11.024][pmid: 18179852] http://dx.doi.org/10.1038/sj.ijo.0803774 http://dx.doi.org/10.1080/02640414.2020.1713688 http://dx.doi.org/10.1136/bmj.320.7244.1240 http://dx.doi.org/10.1136/bmj.39238.399444.55 http://dx.doi.org/10.2307/3088292 http://dx.doi.org/10.1007/s11136-017-1707-1 http://dx.doi.org/10.1007/s11136-017-1707-1 http://dx.doi.org/10.1016/j.ejim.2015.04.013 http://dx.doi.org/10.1093/her/12.3.385 http://dx.doi.org/10.1016/j.socscimed.2007.11.024 108 sajsm vol 19 no. 5 2007 introduction chronic obstructive pulmonary disease (copd) is a major cause of disability and premature death and as a result is regarded as global health priority. 7 while the relative contribution of coronary heart disease and stroke towards death is on the decline, mortality from copd is on the increase. 17 this trend has prompted an increase in the number of studies investigating the efficacy of different treatment modalities within pulmonary rehabilitation (pr), and has resulted in the synthesis of a number of consensus statements and clinical guidelines by various associations. pr can be defined as ‘an evidence-based multidisciplinary and comprehensive intervention for patients with chronic respiratory disease who are symptomatic and often have decreased daily life activities. integrated into individualised treatment of the patient, pulmonary rehabilitation is designed to reduce symptoms, optimise functional status, increase participation, and reduce health care costs through stabilising or reversing systemic manifestations of the disease. 37 a number of deleterious effects have been associated with copd and include, among others, social isolation, exercise deconditioning, depression, muscle wasting and impaired health-related quality of life (hrql). 9,55,56 consequently, pr programmes should aim to treat the patient holistically. this invariably means adopting an interdisciplinary approach where various health care professionals address the different components represented in fig. 1. commentary copd: is there evidence to support a role for resistance training in improving measurable health-related quality of life in pulmonary rehabilitation? abstract chronic obstructive pulmonary disease (copd) is one of the leading causes of morbidity and mortality. as such, the disease places a significant burden on health care services. although the pathogenesis of copd is complex, progressive airflow limitation and a chronic inflammatory response are two hallmark characteristics of the disease. in addition, systemic manifestations such as peripheral muscle dysfunction have recently received considerable attention in the literature. pulmonary rehabilitation is an evidence-based multidisciplinary intervention that has been shown to produce clinically relevant outcomes. one important component of rehabilitation is exercise. with the majority of copd patients presenting with muscle weakness and exercise intolerance, the inclusion of resistance training into a pulmonary rehabilitation programme would seem appropriate. compared with other exercise/training modalities only a small number of studies have investigated the effects of resistance training in copd patients. although further research is required to identify the optimal mode, intensity and frequency, it appears that resistance training may prove to be a valuable intervention for copd patients enrolled in pulmonary rehabilitation programmes. correspondence: stuart semple department of sport, rehabilitation and dental sciences tshwane university of technology private bag x680 pretoria 0001 tel: (012) 382-4324 fax: (012) 382-5801 cell: 082 452 4461 e-mail: semplesj@tut.ac.za s j semple, dtech a j mckune, dtech department of sport, rehabilitation and dental sciences, tshwane university of technology, pretoria fig. 1. fundamental components of pulmonary rehabilitation programmes. psychosocial support exercise training patient education physiotherapy pharmacotherapy weight management & nutrition pulmonary rehabilitation  pg108-113.indd 108 1/11/08 11:11:19 am sajsm vol 19 no. 5 2007 109 copd pathophysiology copd is ‘a disease state characterised by airflow limitation that is not fully reversible. the airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases’. 35 noxious stimuli such as viral infections and inhaled irritants, especially cigarette smoking, results in irritation of the respiratory tract mucosa. it has been suggested that this continual irritation induces epithelial injury and thus provides the stimulus for inflammatory infiltrate. 11 dominance of a chronic inflammatory state within the mucosa results in mucus hypersecretion, ciliary dysfunction, oedema and structural changes such as fibrosis and loss of parenchymal integrity. 38,45 the resultant swelling of the mucosa and subsequent narrowing of the lumen result in airflow obstruction and air trapping/hyperinflation. the inhibition of normal gaseous exchange, i.e. impaired lung function, results in hypoxaemia, which in turn induces dyspnoea, a factor that may deter patients from participating in physical activity. 1,10 skeletal muscle dysfunction inflammatory sequelae are central to the pathogenesis of copd, and while it has traditionally been defined as a disease of the airways, significant systemic factors manifest in copd patients, making it a multi-component disease. 60 a common finding in patients suffering from copd is muscle weakness and a reduction in muscle mass. 3,23,45 it appears that lower limb muscles are more affected than those of the upper limbs. 3,23 potential factors contributing to muscle wasting in copd patients are represented in fig. 2. it should be noted that these factors may all contribute in varying degrees towards skeletal muscle dysfunction. the reduction in fat free mass in copd patients may negatively impact on ‘physical function, health status and survival’. 25 recently, muscle dysfunction has received considerable attention within the literature as a hallmark manifestation of copd. skeletal muscle comprises approximately 73% of body mass. 31 in addition to affecting hrql, dysfunction of skeletal muscle has important implications for exercise tolerance and physical rehabilitation. physiological or structural alterations that have been documented in the skeletal muscle of copd patients include: increased proportion of type ii fibres; 47 reductions in myosin heavy chain type i isoforms; 34 reductions in uncoupling protein-3lmrna (protects against mitochondrial damage) and intramyocellular triglyceride in oxidative fibres; 46 reduced vastus lateralis mitochondrial density; 18 reductions in crosssectional area of type iix fibres and increased fibrosis; 19 reductions in oxidative enzymes (correlated with number of type i fibres) and lowered oxidative capacity in type ii fibres; 20 decreased muscle capillarity 26 and reductions in peroxisome proliferator-activated receptors (involved in mitochondrial biogenesis). 43 gosker et al. 21 recently confirmed that the severity of copd is associated with reductions in the proportion of type i fibres. the aforementioned factors together with the finding that lactic acidosis occurs earlier during exercise in copd patients compared with healthy subjects, 33 may partly explain why copd patients fatigue quicker and experience exercise intolerance. this in turn may deter individuals from participating in physical activity and promote physical deconditioning, ultimately fuelling the progression of copd (fig. 3). exercise and pulmonary rehabilitation pulmonary rehabilitation (pr) programmes can improve hrql in copd patients. 12 exercise intervention is arguably one of the most important components of a pr programme. 30,37,44,57,58 exercise intolerance in copd patients cannot be solely attributed to ventilatory limitations. 52 rather, it has been proposed that the limitations are multifactorial and include metabolic and gas exchange abnormalities, peripheral muscle dysfunction, cardiac impairment and exertional symptoms. 39 a number of studies have shown the positive effects that exercise training may exert on a variety of clinical symptoms in copd patients. the mode of exercise most extensively researched has been that of endurance/aerobic type activities. in addition, a substantial number of investigations have been conducted into the effects of inspiratory and expiratory ventilatory training in copd patients. although most copd patients experience muscle weakness, comparatively fewer studies have investigated resistance-training reduced contractile activity (deconditioning) reduced insulin-like growth factor i reduced testosterone increased proinflammatory cytokines reduced dietary energy intake hypoxaemia glucocorticoid therapy muscle wasting insulin resistance  fig. 2. factors involved in muscle wasting in copd (adapted from jagoe and engelen (25) ). pulmonary rehabilitationimmobility increased v requirement physical deconditioning decreased exercise capacity increased breathlessness decreased v requirement physical reconditioning increased exercise capacity decreased breathllessness chronic pulmonary disease e e  fig. 3. cycle of disabling breathlessness, physical inactivity and deconditioning in copd. (from cooper cb. exercise in chronic pulmonary disease: limitations and rehabilitation. med sci sports exerc 2001; 33(7): s643s646, with permission.) pg108-113.indd 109 1/11/08 11:11:21 am 110 sajsm vol 19 no. 5 2007 effects in copd patients as a modality in isolation. to the best of the authors' knowledge table i contains the only studies that have documented the effects of resistance training in copd patients. some of these studies compared a resistance training group versus other interventions. however, the alterations summarised in table i represent the effects of only resistance training and no other combined intervention. copd is not just a disease of the respiratory system. it is now well established that the skeletal muscles of copd patients are both morphologically and functionally different from those of healthy individuals. 19 the extent of the changes is so pronounced that copd has been termed a muscle disease. 57 since exercise intolerance in copd cannot be attributed to ventilatory limitations alone, and skeletal muscle table i. effects of resistance training on selected variables in copd patients reference participants intervention significant alterations (p<0.05) simpson et al. 49 copd patients (n=14, weightlifting 3x/wk for 8 wks 3 x 10 reps; increased patients’ mastery over the mean fev1 39.5% predicted, workload increased from 50% of 1rm demands of daily living. improvements mean age 73 years) in week 1 to 85% of 1rm in week 8; in fatigue and dyspnoea; time to fatigue 1rm re-evaluated every 6 session; during cycling at 80% of maximum single arm curl, leg press and leg extension improved; 1rm improvements in arm curl (33%), leg press (16%) and leg extension (44%) clark et al. 8 copd patients (n=26, dynamic weight training exercises increases in maximum weight lifted mean fev1 76% (n=8). 2x/wk for 12 wks; workload (isotonic) observed for 5 out of the predicted, mean age 51 70% of 1rm for 12 wks; after week 6, 8 exercises; sustained (60s) isokinetic years) 1rm assessed and workload muscle work, endurance work (joules) adjusted to ‘new’ 70%; upper and and maximal tidal volume improved lower body exercises spruit et al. 50 copd patients (n=24, dynamic strengthening exercises increases in knee extension, knee mean fev1 40% (machines & pulleys). 3x/wk for 12 flexion, shoulder abduction, and predicted, mean age 64 wks; initial intensity 70% of 1rm (3 x elbow flexion force; 38% improvement years) 8 reps); weekly ↑ 5% of 1 rm in 6mwd; increased peak watts during an incremental cycling test; improved hrql ortega et al. 40 copd patients (n=17, dynamic strengthening exercises shuttle walking test (m) and endurance mean fev1 40% (‘gymnastics apparatus’) 3x/wk for 12 test (min) improved; strength predicted, mean age 66 wks; 4 x 6-8 reps, 70-85% of 1rm measurements (kg) in chest pull, years) rm testing conducted every 2 butterfly, neck press, leg flexion and wks to adjust workload; upper and leg extension improved; dyspnoea lower body exercises and hrql improved wright et al. 61 copd patients (n=20, upper and lower body dynamic strength/machine cycle ergometry performance mean fev1 54% predicted, exercises 2x/wk for 2wks; 3 x 12 reps (adaptation improved in training group mean age 56 years) phase – submaximal intensity), then 3x/wk (18.7%); improved hrql 2-4 x 10 reps, for 5 wks, then 3/wk 2-4 x 8-10 reps for 5 wks (focus on intensive eccentrics) kongsgaard et al. 29 copd patients (n=6, progressive resistance training 2x/wk adl (walking 400 m, climbing stairs, mean fev1 48% predicted, for 12 wks; 4 x 8 reps (2-3min between sets), carrying 5 kg) improved; self-reported mean age 71 years) 80% of 1rm; leg press, knee extension, health improved, knee extension knee flexion; workload adjusted weekly and trunk flexion strength improved, gait time (30 m) and stair climbing time decreased hoff et al. 24 copd patients (n=6, horizontal leg press, 8 wk (24 sessions); dynamic rate of force development, mean fev1 32% predicted, 4 x 5 reps, 85-90% of 1rm; 2.5 kg progressions 1rm and peak static force improved; mean age 62 years) implemented when subject could mechanical efficiency of cycling perform more than 5 reps (40w) improved by 31%; rpe at 40w reduced; improved fev1 (21%), fvc pg108-113.indd 110 1/11/08 11:11:21 am sajsm vol 19 no. 5 2007 111 dysfunction is a significant component of the disease, it would seem appropriate to incorporate resistance training into a pr programme. resistance training ‘involves the voluntary activation of specific skeletal muscles against some form of external resistance, which is provided by body mass, free weights (barbells and dumbbells), or a variety of exercise modalities (machines, springs, elastic bands, manual resistance etc.)’. 59 the potential benefits of resistance training in apparently healthy individuals have been reviewed by a number of authors, and includes improvements in muscle strength, increases in muscle size (hypertrophy), increases in protein synthesis, reductions in visceral fat, and reductions in risk factors associated with chronic disease such as diabetes, cardiovascular disease, cancer and osteoporosis. 14,59 the latter may prove beneficial for copd patients, as many suffer from co-morbid conditions. it is arguable that any intervention employed within a pr programme should directly or indirectly serve to improve the patient’s quality of life. with this in mind, the question should be asked: do improvements in strength conferred from resistance training translate to improvements in functional capacity in copd patients? there is evidence to support the value of resistance training in reducing functional limitations in healthy individuals. 5 from the randomised controlled studies summarised in table i, it is apparent that strength of specific muscles improved in 6 out of 6 of the studies in which it was measured. in addition, improved activities of daily living, the mastery thereof, and/or hrql were significantly enhanced in 5 of the 7 studies. hrql is most commonly measured using the chronic respiratory disease questionnaire. 22 the questionnaire, which has been validated for use in a clinical setting, measures four categories pertaining to physical and emotional discomfort during normal daily activities. the patient’s responses are scored on a 7-point likert scale for categories of dyspnoea, fatigue, emotional function and mastery. although the interventions among the studies differed, all used patients with copd. it remains to be seen what effect resistance training may have on patients who have other pulmonary conditions/disorders. all the studies implemented the principle of progression and the training intensity was based on nothing ‘lighter’ than 70% of the subject’s one repetition maximum. no authors reported adverse effects of the training despite some interventions being of a high intensity (≥85% of 1rm). improvements in maximal tidal volume and fev1 in the studies by clark et al. 8 and hof et al. 24 respectively, were the only documented changes in pulmonary function parameters. although fev1 is important in the diagnosis of copd, it cannot be reliably correlated with exercise capacity, dsypnea or hrql. 10 thus, the lack of improvements in pulmonary function parameters following resistance training interventions may not be clinically significant. a potential limiting factor in terms of interpreting the efficacy of resistance training in the pr programmes referenced in table i is that there are large discrepancies in the ages of the participants. in addition, the studies fail to indicate what the participant’s level of activity and co-morbid status was before being diagnosed with copd. this implies that the participants utilised in the studies may have shown favourable benefits from the training interventions because they may have been sedentary (or active) for many years prior to their diagnosis. thus, the ‘true’ benefits conferred by the resistance training are difficult to quantify accurately. more studies have been conducted on the effects of endurance training in pr than any other modality. 9 in addition to the studies referenced in table i, a number of researchers have looked at a combination of strength-endurance interventions in copd patients. 2,4,3,28,32 results from these studies do in some instances support a combined programme over endurance or resistance training alone. the reported additive effects of combined interventions (resistance and endurance) in some studies have gained support for its incorporation into rehabilitation programmes. 4,28,37,56 when summarising randomised controlled trials comparing different exercise modes on copd patients, puhan et al. 42 reported that ‘strength exercise led to larger improvements of hrql than endurance exercise’. although only 4 studies (strength v. endurance) were compared for the purposes of the review, the results do highlight the potential therapeutic value of strength/ resistance training. an advantage of resistance training is that it stresses the cardiorespiratory system less when compared with traditional aerobic exercise (cycling, walking, jogging). the reduced metabolic demand of resistance training means lower levels of lactate accumulation and dyspnoea, factors that would encourage patients to adhere to physical training interventions. resistance training and molecular adaptations in skeletal muscle it may be counter-intuitive to recommend resistance training to copd patients due to the shift from a slow to fast twitch phenotype, observed in their skeletal muscle. 21,34,47 a shift in distribution from slow to fast twitch fibres gives rise to altered activities of key oxidative and glycolytic enzymes 62 that may decrease oxidative capacity and increase the risk of developing insulin resistance. 48 whether resistance training exacerbates this phenotype switch, decreasing functional and oxidative capacity further, or maintains the status quo, has not been determined in copd patients. in addition, it was recently hypothesised that resistance training may only induce brief 5’amp-activated protein kinase (ampk) activation (possibly not at all), resulting in limited ampk-dependent adaptations such as mitochondrial biogenesis. 51 with the skeletal muscle of copd patients already exhibiting reduced mitochondrial biogenesis, oxidative enzymes and oxidative capacity, 18,43 the possibility that resistance training may exacerbate this situation requires clarification. in contrast to the above possible detrimental effects of resistance training for copd patients, recent research has shown that acute resistance training promotes skeletal muscle angiogenesis and hence capillarity. 6,16,54 this finding provides support for the use of resistance training in copd patients, who display decreased muscle capillarity. 26 specifically, research has shown that vascular endothelial pg108-113.indd 111 1/11/08 11:11:22 am 112 sajsm vol 19 no. 5 2007 growth factor (vegf) mrna is increased 2.9-fold above rest 24 hours after resistance exercise in young and aged men as determined by pooled mrna microarray analysis. 27 in the most recent study, acute resistance exercise (3 sets of 10 repetitions knee extension at 60 80% of 1 rm, 2 minutes’ rest between each set) significantly increased skeletal muscle (vastus lateralis) vegf mrna and protein, plasma vegf protein and skeletal muscle vegf receptor (kdr and nrp1) mrna in sedentary, young (range 24 32 years of age) individuals (6 men, 1 woman). the authors concluded that early angiogenic signalling for vegf is increased by acute resistance exercise although additional research is required to determine the signal transduction pathways responsible for up-regulating the angiogenesis growth factors and receptors. 16 it remains to be determined whether the increased skeletal muscle angiogenesis/capillarity induced by resistance training in healthy young individuals also occurs in copd patients, who are typically older. in addition, research is also required to determine whether resistance training induced increases in skeletal muscle angiogenesis/ capillarity has any beneficial effect on the functional capacity and hrql of copd patients. anti-inflammatory nature of resistance training? from the above discussion it can be seen that the precise molecular mechanisms in skeletal muscle that may underlie beneficial or detrimental resistance training transfers for pr patients are complex, with many areas requiring further research. an additional area of research that is currently receiving worldwide attention relates to the possible anti-inflammatory effect of exercise. with copd exhibiting a strong inflammatory component, 35 it may just be that exercise serves to attenuate the chronic inflammatory response in these patients. oxidative stress (free radical species) modulates aspects of inflammatory-induced alterations in skeletal muscle function. 53 eight weeks of aerobic exercise (cycle ergometry) 3 times per week for 60 minutes has been shown to reduce exerciseinduced oxidative damage in copd patients. 41 exerciseinduced elevations in cytokines (particularly interleukin-6) have been implicated as potential role players involved in inducing the anti-inflammatory effect associated with exercise. 15 whether resistance training promotes a downregulation in oxidative/inflammatory responses remains to be elucidated. high doses of corticosteroids have been shown to induce skeletal myopathies. 36 if indeed the mechanism by which exercise imparts favourable health benefits is antiinflammatory sequelae, then it may reduce or impact on the patient’s reliance on medications. this in turn could affect hrql as certain medications have undesirable side-effects. conclusion although guidelines have been established, 52 the optimal mode, frequency and intensity of resistance training (especially among differing pulmonary pathologies) still requires further investigation. this is important in order to establish the true efficacy of resistance training for copd patients. this in turn would prevent rehabilitation practitioners from prescribing to or implementing practices that are not supported by evidence. recently, evidence-based clinical guidelines jointly generated by the american college of chest physicians (accp) and the american association of cardiovascular and pulmonary rehabilitation (aacvpr) reject the inclusion of inspiratory training as part of a pr programme based on lack of evidence. 44 this highlights the fact that although papers have been published advocating the use of inspiratory training in copd patients, further research is still required. similarly, further research is still required to show that resistance training may reduce and/or reverse muscle wasting and dysfunction. currently, no studies have been conducted in which muscle biopsies have been performed to determine if cellular/biochemical changes occur as a result of strength training in copd patients. 44 based on the results of studies that have investigated the effects of resistance training on copd patients, it seems that resistance training may indeed contribute favourably to the exercise training component within a pr programme. this ‘sentiment’ is acknowledged by the accp and the aacvpr. although ‘clinicians underestimated the degree to which skeletal muscle weakness contributes to patient morbidity’. 53 it seems that within the literature more and more authors are promoting the inclusion of resistance training within pr programmes. many argue that a combination of endurance and strength training would be most beneficial for the patient. future studies are required to shed light on the extent to which resistance training may impact on functional capacity and hrql in copd patients. in addition, studies are required to investigate the role of resistance training in altering inflammatory responses as well as beneficial or detrimental molecular pathways within the skeletal muscle of 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r, decramer m. chronic obstructive pulmonary disease and chronic heart failure. two muscle diseases? j cardiopulm rehabil 2004; 24: 137-45. 58. troosters t, gosselink r, langer d, decramer m. pulmonary rehabilitation in chronic obstructive pulmonary disease. respir med 2007; 3: 57-64. 59. winett ra, carpinelli rn. potential health-related benefits of resistance training. prev med 2001; 33: 503-13. 60. wouters efm. minimal clinically important differences in copd: body mass index and muscle strength. j chronic obstruc pulm dis 2005; 2: 149-55. 61. wright pr, heck h, langenkamp h, franz kh, weber u. influence of resistance training on pulmonary function and performance measures of patients with copd. pneumologie 2002; 56: 413-7. 62. zierath jr, hawley ja. skeletal muscle fiber type: influence on contractile and metabolic properties. plos biol 2004; 2: 1523-27. pg108-113.indd 113 1/11/08 11:11:24 am original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license understanding the influence of 24-hour movement behaviours on the health and development of preschool children from low-income south african settings: the sunrise pilot study c e draper, 1,2 phd, s a tomaz,2,3 phd, c j cook,1,2 phd, s s jugdav,4 maspr, c ramsammy,4 m psych, s besharati,4 phd, a van heerden,5,1 phd, k vilakazi,5 m soc sci, k cockcroft,4 phd, s j howard,6 phd, a d okely,6 edd 1 south african mrc/wits developmental pathways for health research unit, faculty of health sciences, university of the witwate rsrand, johannesburg, south africa 2 division of exercise science and sports medicine, uct research centre for health through phy sical activity, lifestyle and sport, department of human biology, faculty of health sciences, university of cape town, south africa 3 faculty of health sciences and sport, university of stirling, uk 4 department of psychology, university of the witwatersrand, south africa 5 human sciences research council, south africa 6 early start, faculty of social sciences, university of wollongong, australia corresponding author: c e draper (catherine.draper@wits.ac.za) in 2018, the south african (sa) 24-hour movement guidelines for birth to five years were released.[1] these guidelines recommend that preschool children should, in a day, spend an average of 180 minutes in total physical activity (tpa) which includes 60 minutes of ‘energetic play’ (moderateto vigorous-intensity physical activity, mvpa), engage in less than one hour of screen time, and get 10-13 hours of sleep.[1] these guidelines align with the world health organisation (who),[2] canada, and australia, who all have 24-hour integrated guidelines for young children; and they align with the united kingdom guidelines on physical activity in the early years. development of these guidelines stems from the recognition that movement behaviours play a foundational role in the prevention and management of childhood obesity and noncommunicable diseases, as highlighted by the who ending childhood obesity report, as well as the importance of healthy movement behaviours for optimal development in childhood.[3] the development of global and national guidelines has highlighted the need for appropriate surveillance methods. this led to sunrise – an international study of movement behaviours in the early years (https://sunrise-study.com). south africa was one of the first countries to participate in the sunrise pilot study. the primary aim of the main sunrise study is to determine the proportion of children sampled in participating countries who meet the who global guidelines for physical activity, sedentary behaviour and sleep for children under five years of age. secondary aims are to: (1) determine if proportions differ by sex, urban/rural location or between different levels of human and economic development; and (2) assess associations between movement behaviours and indicators of motor and cognitive development. this paper on the south african sunrise pilot study presents descriptive findings on movement behaviours in preschool children from two low-income settings (rural and urban), and the associations between these movement behaviours, adiposity, motor skills and cognitive development. this paper also comments briefly on the feasibility and acceptability of the sunrise outcome measures. background: the international study of movement behaviours in the early years, sunrise, was initiated to assess the extent to which young children meet movement behaviour guidelines (physical activity, sedentary behaviour, screen time, sleep). objective: the south african sunrise pilot study assessed movement behaviours in preschool children from two low-income settings, and associations between these movement behaviours, adiposity, motor skills and executive function (ef). methods: preschool child/parent pairs (n = 89) were recruited from preschools in urban soweto and rural sweetwaters. height and weight were measured to assess adiposity. physical activity was assessed using accelerometers while sedentary behaviour, screen time and sleep were assessed via parent report. fine and gross motor development were measured using the ages and stages questionnaire-3, and ef was assessed using the early years toolbox. results: the proportion of children meeting the physical activity guideline was 84% , 66% met the sleep guideline ,48% met the screen time guideline , and 26% met all three guidelines. rural children were more active, but spent more time on screens compared to urban children. most children were on track for gross (96%) and fine motor (73%) development, and mean ef scores were in the expected range for all ef measures. ef was negatively associated with screen time, and gross motor skills were positively associated with physical activity. conclusion: the south african sunrise study contributes to the growing literature on 24-hour movement behaviours in sa preschool children, and highlights that these behaviours require attention in this age group. keywords: early childhood development, physical activity, screen time, sleep s afr j sports med 2020;32:1-7. doi: 10.17159/2078-516x/2020/v32i1a8415 mailto:catherine.draper@wits.ac.za https://sunrise-study.com/ http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8415 https://orcid.org/0000-0002-4002-7991 https://orcid.org/0000-0002-7531-3250 https://orcid.org/0000-0002-2885-437x https://orcid.org/0000-0001-9718-8887 https://orcid.org/0000-0003-4822-3054 https://orcid.org/0000-0003-2530-6885 https://orcid.org/0000-0001-7905-9985 https://orcid.org/0000-0002-6166-8050 https://orcid.org/0000-0002-1258-3210 https://orcid.org/0000-0002-1626-8170 https://orcid.org/0000-0003-2836-7982 original research sajsm vol. 32 no. 1 2020 2 methods study settings and recruitment data were collected from two low-income settings in south africa: urban soweto, johannesburg (gauteng), and rural sweetwaters (kwazulu-natal). children and parents (or primary caregivers, n = 89 child/parent pairs) were recruited from four preschools in soweto, and three preschools in sweetwaters. written informed consent was obtained from parents for all children and parents consented to complete the sunrise parent questionnaire. ethical approval for this study was obtained from the human research ethics committee (medical) at the university of the witwatersrand (ref: m180490). measures and procedures all data collection with children took place at the preschools during the preschool day. parent questionnaires were interviewer-administered and completed at a time convenient for parents, either at home or their child’s preschool. data were collected by trained fieldworkers. in sweetwaters, the questionnaire was administered in isizulu and in soweto it was administered in english, with explanation in local languages where necessary. anthropometrics the children’s height and weight were measured using a portable stadiometer (leicester 214 transportable stadiometer; seca, germany) and a calibrated scale (soehnle 7840 mediscale digital, soehnle industrial solutions, germany). all measurements were taken twice, and an average was used for analysis. height and weight were used to calculate the body mass index (bmi). bmi and associated z-scores were computed using the who anthroplus software (http://www.who.int/growthref/tools/en/). international obesity task force cut-offs [4] were applied to bmi scores to classify children as thin, normal weight, overweight, and obese. accelerometry physical activity was measured using hip-worn actigraph gt3x+ accelerometers (actigraph llc, pensacola, fl; usa). the device was set to start recording at midnight on the day of fitting and was collected four days later to ensure 72 continuous hours of wear. actilife v.6 (actilife software; pensacola, fl; usa) was used to download in 15-second epochs, clean and score all accelerometry data. visual inspection was conducted to determine if participants wore the device for a minimum of 24-hours. a predetermined time filter (5 am to 11.30 pm) was applied to all ‘valid’ days to avoid sleeping time being classified as non-wear or sedentary time. only data recorded for each ‘valid’ day were considered for analyses. non-wear time (including daytime naps, and when device was removed for bathing) was defined as 20 minutes or more of consecutive zeroes and was removed.[5] cut points used for light-intensity physical activity (lpa) and moderate to vigorous-intensity physical activity (mvpa) were ≥200 counts.15s-1 and >420 counts.15s-1, respectively.[6-7] duration of time spent in lpa, mvpa and total physical activity (tpa) were determined. motor skills the ages and stages questionnaire-3 (48 months, asq-3), a developmental screening assessment,[8] was used to assess gross motor and fine motor skills. it has a categorical output for each motor skill component (child requires follow-up and further assessment/action, child is developing on schedule but may benefit from extra practice in some of the skills, child is developing on schedule). executive function executive function (ef) is the marker of cognitive development used in sunrise and refers to the cognitive control processes that enable working with mental information (working memory), while resisting distractions and contrary impulses (inhibition) and flexibly (re-) directing attention as needed (shifting).[9] ef in the early years has been found to predict lifelong achievement, health, wealth, quality of life, academic achievement and school readiness.[9] the ipad-based early years toolbox (eyt) was used to assess ef.[10] this is available in five local south african languages (isizulu, sesotho, isixhosa, xitsonga and afrikaans), takes ~20 minutes to complete per child, and includes assessments of working memory, inhibition and shifting. the translated versions have been used previously.[11] an exploratory factor analysis (efa)-derived factor score (ef composite score) was computed for these three eyt tasks so as to not constrain the number of planned analyses, and to more purely index ef (than any single ef measure in isolation). inter-task correlations (coefficients from 0.18 to 0.43) were similar to those previously reported (where, ref?), and efa supported their combination.[10] sunrise parent questionnaire the interviewer-administered sunrise parent questionnaire covered the following in relation to the child, for the previous week: pa (total pa, and moderateto vigorous-intensity pa, mvpa), time spent outside, screen time and use of screens before bedtime, time spent restrained (strapped in and unable to move), time spent sitting, and sleep (typical hours slept, bedtime routine). parents were also asked how they used screens with their child, how often they read to their child, and the highest education level in household. statistical analysis data were analysed using spss statistics for windows (v 25.0). continuous data were presented as mean ± sd if normally distributed or median (interquartile range) if not. to examine differences between boys and girls, and rural and urban, mann-whitney-u tests (for continuous variables) and pearson’s chi2 test (for categorical variables) were performed. to test for associations between variables, spearman’s rank correlation coefficients were calculated. kruskal-wallis tests were conducted to examine differences in bmi-for-age z score (baz), gross motor skills, fine motor skills, and ef (efaderived factor) between children meeting one, two or three http://www.who.int/growthref/tools/en/ original research 3 sajsm vol. 32 no. 1 2020 guidelines. children were classified as meeting pa guidelines if they spent an average of 180 minutes per day in tpa, inclusive of 60 minutes per day of mvpa (objectively measured). they were classified as meeting the screen time guideline if they had less than one hour per day of parentreported screen time, and were getting 10-13 hours of parentreported sleep per 24-hour day. results the final sample used for analysis comprised 88 child/parent pairs (41 girls, 47%;47 boys, 53%; 39 urban soweto, 44%; 49 rural sweetwaters, 56%). table 1 summarises children’s age and anthropometric characteristics. there were no significant differences between boys and girls for age or any anthropometric outcomes (all p > 0.05). the only significant table 1. children’s age and anthropometric characteristics, by sex and setting total (n = 88) boys (n = 47) girls (n = 41) p value‡ rural (n = 49) urban (n = 39) p value§ age (y) 4.5 ± 0.3 4.5 ± 0.4 4.5 ± 0.3 0.964 4.5 ± 0.3 4.5 ± 0.4 0.282 height (cm) 103.5 ± 4.6 103.6 ± 5.1 103.4 ± 4.1 0.802 102.9 ± 4.8 104.3 ± 4.3 0.183 weight (kg) 17.6 ± 3.0 18.6 (15.7–18.9) 17.5 ± 2.6 17.2 (15.8–18.6) 17.6 ± 3.3 16.7 (15.5–18.7) 0.544 17.6 ± 3.1 16.8 (15.6–18.6) 17.5 ± 2.8 17.3 (15.7–18.7) 0.857 bmi (kg.m-2) 16.3 ± 2.2 15.9 (15.2–17.1) 16.3 ± 1.9 16.2 (15.2–17.1) 16.4 ± 2.5 15.7 (15.3–17.1) 0.910 16.6 ± 2.2 16.3 (15.5–17.2) 16.0 ± 2.1 15.4 (14.7–16.9) 0.063 haz -0.65 ± 0.90 -0.69 ± 0.97 -0.61 ± 0.82 0.649 -0.83 ± 1.10 -0.43 ± 0.77 0.038* waz 0.02 ± 1.06 -0.10 (-0.68–0.53) -0.01 ± 1.00 -0.10 (-0.65–0.53) 0.07 ± 1.15 -0.10 (-0.69–0.55) 0.943 0.02 ± 1.06 -0.01 (-0.68–0.47) 0.02 ± 1.08 -0.09 (-0.68–0.54) 0.857 baz 0.65 ± 1.30 0.39 (-0.07–1.27) 0.66 ± 1.22 -0.10 (-0.69–0.55) 0.64 ± 1.39 0.33 (0.05–1.16) 0.757 0.82 ± 1.30 0.67 (0.14–1.34) 0.44 ± 1.27 0.14 (-0.40–1.07) 0.057 data are presented as mean ± sd for normally distributed data; not normally distributed data includes median (25 th–75th percentile) for the total sample. *indicates significance at p < 0.05; ‡p value for comparison by sex; §p value for comparison by setting. bmi, body mass index; haz, height-for-age z score; waz, weight-for-age z score; baz, bmi-for-age z score. table 2. accelerometry, motor skill and executive function results, by sex and setting total (n = 77) boys (n = 40) girls (n = 37) p value‡ rural (n = 43) urban (n = 34) p value§ sb (min/d) 748 ± 83 752 ± 83 745 ± 84 0.743 723 ± 75 782 ± 82 0.001* lpa (min/d) 127 ± 28 124 ± 29 129 ± 28 0.426 140 ± 24 110 ± 25 <0.001* mpa (min/d) 98 ± 30 101 ± 30 95 ± 31 0.434 110 ± 28 83 ± 26 <0.001* vpa (min/d) 30 ± 15 28 (20–39) 32 ± 16 30 (21–42) 27 ± 12 27 (17–34) 0.114 34 ± 16 30 (24–43) 25 ± 11 23 (17–32) 0.008* mvpa (min/d) 128 ± 43 133 ± 44 122 ± 41 0.249 144 ± 42 108 ± 35 <0.001* tpa (min/d) 254 ± 67 257 ± 70 251 ± 65 0.692 283 ± 61 218 ± 56 <0.001* total (n = 88) boys (n = 47) girls (n = 41) p value‡ rural (n = 49) urban (n = 39) p value§ gross motor skills† 56 ± 10 60 (60–60) 56 ± 11 60 (60–60) 56 ± 10 60 (60–60) 0.342 57 ± 12 60 (60–60) 55 ± 8 60 (53–60) <0.001* fine motor skills† 44 ± 16 50 (30–55) 42 ± 16 45 (30–55) 46 ± 16 50 (36–55) 0.166 36 ± 17 40 (20–50) 52 ± 9 55 (50–55) <0.001* working memory† 3.4 ± 2.6 1.3 (0.3–2.0) 3.4 ± 2.8 1.3 (0.0–2.3) 3.5 ± 2.3 1.3 (0.3–2.0) 0.972 2.1 ± 2.4 0.3 (0.0–1.7) 5.0 ± 1.7 2.0 (1.3–2.3) <0.001* inhibition 0.57 ± 0.19 0.57 ± 0.18 0.57 ± 0.20 0.965 0.54 ± 0.15 0.61 ± 0.23 0.089 shifting 2.20 ± 3.47 0.00 (0.00–3.00) 2.19 ± 3.54 0.00 (0.00–3.00) 2.22 ± 3.43 0.00 (0.00–3.00) 0.771 0.37 ± 0.93 0.00 (0.00–0.00) 4.51 ± 4.08 3.00 (0.00–9.00) <0.001* ef composite score† 0.007 ± 1.005 -0.036 (-0.835–0.598) -0.007 ± 1.096 -0.125 (-0.959–0.605) 0.023 ± 0.897 0.081 (-0.723–0.585) 0.636 -0.532 ± 0.683 -0.708 (-1.131–0.017) 0.657 ± 0.949 0.441 (0.046–1.556) <0.001* †n=86; 1 boy & 1 girl refused to complete tests; both from rural setting; data are presented as mean ± sd for normally distributed data; #not normally distributed data includes median (25th–75th percentile); *indicates significance at p <0.001; ‡p value for comparison by sex; §p value for comparison by setting. sb, sedentary behaviour; lpa, light-intensity physical activity; mpa, moderate-intensity physical activity; vpa, vigorous-intensity physical activity; mvpa, moderateto vigorous-intensity physical activity; tpa, total physical activity; ef, executive function; gross and fine motor skills are reported as ages and stages questionnaire-3 scores; working memory, inhibition and shifting are reported as scores on the early years toolbo x tasks. original research sajsm vol. 32 no. 1 2020 4 difference between the urban and rural sub-samples was for height-for-age z score (haz) (p = 0.038). using who cut-offs, 67% of the sample were in the normal range for bmi, 22.7% were identified as being at ‘possible risk of overweight’, and 5.7% and 4.5% were overweight and obese, respectively. using international obesity task force (iotf) cut-offs, 72% of the sample were classified as normal weight, 11% as overweight, 7% as obese, and 10% as thin. table 2 summarises the accelerometry, motor skills and ef results. boys and girls were similar for all pa variables (all p > 0.05). rural children had significantly less sedentary time than urban children (p = 0.001), as well as being more physically active (lpa p < 0.001; mpa p < 0.001; vigorousintensity physical activity (vpa) p = 0.008; mpva p < 0.0005 and tpa p < 0.001). boys and girls were similar for both gross and fine motor skill scores (both p > 0.05), but compared to rural children, urban children had significantly higher fine motor skill scores (p < 0.001). for gross motor skills, 96% of children scored in the highest category (‘developing on schedule’). for fine motor skills, 14% of children scored in the poorest category (‘requires follow-up and further assessment/action’), and 73% in the highest category. for all ef variables, boys and girls were similar (p > 0.05 for all variables). rural children had significantly lower scores compared to urban children for working memory (p < 0.001), shifting (p < 0.001) and the ef composite score (p < 0.001). figure 1 illustrates the number of children meeting the different components of the 24-hour movement guidelines. amongst participants with valid data for all three components (83% of the sample, n = 73), most parents (89%) reported that, in the past week, their child had not been restrained for more than 60 minutes at a time, thus meeting this other component of the sedentary behaviour guideline. when looking at the guidelines separately for the full sample, 65 participants (84% of n = 77 valid) met the pa guideline, 40 (47% of n = 85 valid) met the screen time guideline, and 54 (65% of n = 83 valid) met the sleep guideline. results of the parent questionnaire are presented in table 3. there were no differences between boys and girls for any parent-reported behaviours. parents in the rural setting reported more pa (p < 0.001) energetic play (p = 0.007), screen time (p = 0.002) and time spent sitting (p < 0.001). parentreported screen time practices with the child are shown in figure 2. the percentage of parents who indicated that their child used a screen before bed was 82%, and 49% indicated that there was a screen in the room where the child sleeps. table 3. parent questionnaire results (continuous variables), by sex and setting total (n = 85) boys (n = 45) girls (n = 40) p value‡ rural (n = 48) urban (n = 37) p value§ parent/caregiver age (y)# 35.2 ± 12.5 32.0 (27.0–41.0) 33.2 ± 8.8 37.0 (31.0–48.5) 37.4 ± 15.5 37.0 (29.5–47.3) 0.555 33.8 ± 12.5 30.0 (25.0–39.5) 36.9 ± 12.4 34.0 (28.0–44.5) 0.100 tpa (h/d)# 5.16 ± 2.34 5.0 (3.0–8.0) 4.95 ± 2.24 5.0 (3.0–6.0) 5.39 ± 2.46 5.5 (4.0–8.0) 0.365 6.31 ± 1.79 6.0 (5.0–8.0) 3.66 ± 2.13 4.0 (2.0–5.0) <0.001* energetic play (h/d)# 2.84 ± 2.07 2.0 (1.0–4.0) 2.87 ± 1.94 3.0 (1.0–4.5) 2.80 ± 2.22 2.0 (1.0–4.0) 0.606 3.37 ± 2.14 3.0 (2.0–5.0) 2.16 ± 1.77 2.0 (1.0–3.5) 0.007** screen time (h/d)# 2.10 ± 1.73 1.5 (1.0–3.0) 2.32 ± 2.02 1.5 (1.0–3.0) 1.86 ± 1.32 1.8 (0.9–3.0) 0.568 2.69 ± 1.95 2.75 (1.0–3.8) 1.34 ± 0.97 1.0 (0.6–1.8) 0.002** sleep (h/d)† 10.29 ± 1.70 10.09 ± 1.91 10.52 ± 1.41 0.253 10.08 ± 1.73 10.55 ± 1.65 0.216 time spent sitting (h/d) # 2.10 ± 2.34 1.0 (0.5–3.0) 1.97 ± 2.24 1.0 (0.4–3.0) 2.25 ± 2.47 1.0 (0.5–3.8) 0.497 3.00 ± 2.62 2.25 (0.5–5.0) 0.94 ± 1.17 0.75 (0.33–1.0) <0.001* time spent sitting in a vehicle (weekdays,h/d)# 0.55 ± 1.41 0.0 (0.0–0.5) 0.59 ± 1.58 0.0 (0.0–0.5) 0.51 ± 1.20 0.0 (0.0–0.4) 0.256 0.70 ± 1.78 0.0 (0.0–0.5) 0.36 ± 0.64 0.0 (0.0–0.5) 0.666 time spent sitting in a vehicle (weekends,h/d)# 0.34 ± 0.68 0.0 (0.0–0.42) 0.31 ± 0.61 0.0 (0.0–0.3) 0.38 ± 0.76 0.0 (0.0–0.9) 0.967 0.39 ± 0.76 0.0 (0.0–0.63) 0.28 ± 0.58 0.0 (0.0–0.33) 0.663 †n=83; 2 parents responses excluded; both parents of girls, from the rural setting; all data are presented as mean ± sd for normally distributed data; #not normally distributed data includes median (25th–75th percentile); *indicates significance at p < 0.001; **indicates significance at p < 0.05; ‡p value for comparison by sex; §p value for comparison by setting. tpa, total physical activity. fig. 1. venn diagram illustrating the proportion of children meeting 24-hour movement guideline components (valid n=73) physical activity (≥180min/d, including ≥60min/d mvpa) n=61 (84%) screen time (<1hr/d) n=35 (48%) sleep (10-13 hr/d) n=48 (66%) n=27 (37%) n=24 (33%) n=39 (53%) n=19 (26%) original research 5 sajsm vol. 32 no. 1 2020 approximately half of the parents reported that their child had consistent bedtimes (52% responded ‘yes’) and 70% of parents reported that their child has consistent wake up times. only 10% of parents reported reading to their child every day, and in response to the question: how many days did you or other household members read to this child? 53 parents (60%) reported an average of 3.5±2.3 days. correlation results indicated associations between some variables. ef was negatively associated with baz (rs = -0.31, p = 0.004), gross motor skills (rs = -0.24, p = 0.036), and screen time (rs = -0.31, p = 0.004) and positively associated with fine motor skills (rs = 0.61, p < 0.001). baz was positively associated with tpa (rs = 0.25, p = 0.03) and screen time (rs = 0.22, p = 0.039). gross motor skills were positively associated with both tpa (rs = 0.30, p = 0.010) and mvpa (rs = 0.28, p = 0.019). fine motor skills were negatively associated with tpa (rs = -0.30, p = 0.011). sleep was not associated with any variables. as indicated in table 4, the results of the kruskalwallis test showed no significant differences. however, the mean ranks show that scores are in the expected direction: when two or three guidelines were met, children appeared to have lower baz, better gross motor skills and ef skills compared to children who only met one guideline. regarding the feasibility and acceptability of the sunrise outcome measures, most measures have been used successfully in previous south african studies with this age group, and performed well in this study. these included anthropometric measures, use of the hip-worn actigraph gt3x+ accelerometers, and the eyt. this is not the first study to use the asq-3 in south africa, but it confirmed that it is a feasible and acceptable measure of motor skills in lowincome south african settings. lastly, the sunrise parent questionnaire was feasible and acceptable in these settings, only if it was administered by a fieldworker. parents found it difficult to report on their child’s pa while at preschool, which suggests that parentreported pa levels should be interpreted with caution, and that the sunrise main study in south africa should rely on objectively-measured pa for this age group. discussion the south african sunrise pilot study is the first in the country to include all three movement behaviours, to publish parent-reported screen time in preschool-aged children, and to examine associations between screen time, sleep and other early childhood development outcomes. this study confirms previous findings that overweight and obesity need to be addressed in this age group of south african children, taking into consideration the double burden of overand undernutrition that has been noted in previous national and regional studies.[12-14] in the south african sunrise sample, levels of tpa were lower than in previous studies in this age group from similar settings, although levels of mvpa are comparable, at least in terms of meeting the mvpa guideline.[11,14-15] the difference in tpa is likely due to a higher cut point for lpa used for the sunrise sample, meaning that what had been classified as fig. 2. frequency of parent-reported screen use with the child table 4. mean ranks of children meeting 1, 2, or 3 guidelines, for baz, gross motor skills, fine motor skills and executive function guidelines met 1 (n = 21) mean rank 2 (n = 33) mean rank 3 (n = 19) mean rank χ2 p value baz 37.19 37.77 35.45 0.15 0.929 gross motor skills 35.24 33.63 33.50 0.21 0.895 fine motor skills 33.13 39.36 30.92 2.43 0.297 ef composite score 32.19 37.30 40.06 1.46 0.482 baz, bmi-for-age z score; ef, executive function original research sajsm vol. 32 no. 1 2020 6 lpa in previous studies, is in this study more likely to be classified as sedentary behaviour. although close to twothirds of children in the sunrise sample met the sleep guideline, parent-reported sleep is likely to overestimate actual sleep time. a previous study in soweto that measured sleep objectively in preschool children supports this likely overestimation, since it highlighted late bedtimes and that the majority of children were reliant on daytime naps to meet the guidelines.[14] the sunrise pilot findings regarding the consistency of bedtimes (only 52%) and screen use before bed (82%), included as part of the bedtime routine (60%), add to the need to address sleep behaviour in this age group in lowincome south african settings. less than half of the sample met the screen time guideline, which aligns with the global trend of high proportions of young children exceeding screen time guidelines, including those in lowand middle-income countries. while educating parents about south africa’s guidelines,[1] it is clear from these findings that parents in low-income south african settings need support on parenting strategies that do not involve screens, for example, when needing to calm a child down when upset, and keeping a child busy. given that only 10% of parents reported reading to their child, it is possible that encouraging parents to do this, especially as part of their bedtime routine, could be beneficial for reducing screen time, improving early learning outcomes, and encouraging nurturing interactions between parents and children.[1] the gross motor performance of these children aligns with previous research from low-income south african settings that found preschool children perform well in this domain.[11,16] ef in the south african sunrise sample is also comparable to previous south african studies using the eyt in this age group, which found that children perform within and, in some cases exceed, the normal range for ef, and that urban children have better working memory and shifting than rural children.[11] while possible reasons for better than expected ef have been hypothesised,[11] further research is required to better understand young children’s efs in lowincome south african settings. although there were no significant differences for baz, motor skills and ef for children meeting one, two or three guidelines, correlation results were revealing: children with lower screen time demonstrated better ef, and children who engaged in more pa demonstrated better gross motor skills. however, given the cross-sectional nature of this study, it is possible that these relationships are bidirectional and causality cannot be inferred. associations between baz, ef, tpa and gross motor skills need further investigation using larger samples to better understand the effects of meeting specific combinations of the guidelines. this is the first study to investigate the association between ef and fine motor skills in south african preschool children, and may indicate activities that develop fine motor skills, e.g. playing with blocks, puzzles, colouring in and drawing, are also beneficial for ef. this supports the message of south africa’s guidelines[1] that encourage these activities. the negative association between fine motor skills and tpa could be an indication that pa could be displacing activities for developing fine motor skills, or that children who do not have access to resources for fine motor activities choose active play as an alternative. however, this finding could also be explained by limited variance in tpa within the sample (very few children in the sample were engaging in less than 180 minutes of tpa per day). a larger sample with greater variability could more accurately determine the nature of this relationship. the strengths of this study include the use of wellestablished measures for this age group in low-income south african settings, and the benefit of the collective expertise and experience of the sunrise global leadership group to inform on the study design. the main limitation is the small sample size and that the settings are not nationally representative. however, these sites benefited from the research capacity and existing relationships that helped to facilitate community engagement. when planning for the main south african sunrise study, engagement with the community will form a crucial component of its planning and execution. furthermore, this pilot study provided useful insights into recruitment, data collection ‘trouble-shooting’, and other methodological considerations for the main sunrise study in south africa. although it will not be feasible to recruit a nationally representative sample for the main sunrise study, the sample size will be substantially larger (~1000 child/parent pairs) and more diverse. conclusion the south african sunrise pilot study contributes valuable initial findings to the growing literature on 24-hour movement behaviours in south african preschool children, and highlights that these behaviours require attention in this age group. this is particularly important considering the ubiquity of screens and the internet in many areas of south africa. understanding how movement behaviours are associated with key outcomes in early childhood is vital for setting this country’s children on their best trajectories for health and early learning. conflict of interest: the authors declare that they have no conflict of interest. acknowledgements: the authors would like to thank local field workers, karabo setlhafuno and thobeka mbokazi for their assistance with recruitment and data collection, and the hsrc office in sweetwaters for facilitating community entry in sweetwaters. the authors are also grateful to the preschools, parents/caregivers and children for their cooperation and participation. this study was funded through a grant received from the faculty of health sciences at the university of the witwatersrand. for cjc, the support of the dst-nrf centre for excellence in human development at the university of witwatersrand (johannesburg, south africa) towards this research is hereby acknowledged. sat was supported by the harry crossley foundation while conducting this research. ado is supported by a nhmrc investigator grant (leadership fellowship, level 2). original research 7 sajsm vol. 32 no. 1 2020 author contributions: ado led the conception and design of the study, and critical assessed the paper. ced was involved in the conception and design of the study, was involved in the analysis and interpretation of the results, and wrote the initial draft and final version of the paper. sat, cjc, ssj, cr and kv were involved in data collection. sat and cjc led the analysis of the data. sb, avh, kc and sjh provided supervision of students involved in the project, were involved in the interpretation of the results, and critically assessed the paper. all authors commented on drafts of the paper and approved the final version of the paper. references 1. draper ce, tomaz sa, biersteker l, et al. the south african 24hour movement guidelines for birth to five years: an integration of physical activity, sitting behaviour, screen time and sleep. j phys act health 2020;17(1):109-119. [doi: 10.1123/jpah.20190187] [pmid: 31877557] 2. willumsen j, bull f. development of who guidelines on physical activity, sedentary behavior, and sleep for children less than 5 years of age. j phys act health 2020;17(1):96-100. [doi: 10.1123/jpah.2019-0457] [pmid: 31877559] 3. world health organization. report on the commission on ending childhood obesity: implementation report: executive summary. geneva: world health organization; 2017:. http://www.who.int/end-childhood-obesity/publications/echoreport/en/ 4. cole tj, lobstein t. extended international (iotf) body mass index cut-offs for thinness, overweight and obesity. pediatr obes 2012;7(4):284-294. [doi: 10.1111 /j.2047-6310.2012.00064.x] [pmid:22715120] 5. janssen x, basterfield l, parkinson kn, et al. objective measurement of sedentary behavior: impact of non-wear time rules on changes in sedentary time. bmc public health 2015;15:504. [doi:10.1186/s12889-015-1847-6] [pmid: 26001579] 6. pate rr, o’neill jr, brown wh, et al. prevalence of compliance with a new physical activity guidelines for preschool-age children. child obes 2015;11(4):415-420. [doi: 10.1089/chi.2014.0143] [pmid: 26121562] 7. pate rr, almeida mj, mciver kl, et al. validation and calibration of an accelerometer in preschool children. obesity (silver spring) 2006;14(11):2000-2006. [doi:10.1038/ oby.2006.234] [pmid: 17135617] 8. squires j, bricker d. ages & stages questionnaires®, third edition (asq®-3): a parent-completed child monitoring system. baltimore: paul h. brookes publishing co., inc. 2009. 9. diamond a. executive functions. annu rev psychol 2013;64:135–168. [doi: 10.1146/annurev-psych-113011-143750] [pmid: 23020641] 10. howard sj, melhuish e. an early years toolbox for assessing early executive function, language, self-regulation, and social development: validity, reliability, and preliminary norms. j psychoeduc assess 2017;35(3):255–275. [doi: 10.1177/0734282916633009] [pmid: 28503022] 11. cook cj, howard sj, scerif g, et al. associations of physical activity and gross motor skills with executive function in preschool children from low-income south african settings. dev sci 2019;22(5):e12820. [doi: 10.1111/desc.12820] [pmid: 30801916] 12. south africa. national department of health, statistics south africa, south african medical research council, et al.. south africa demographic and health survey 2016. pretoria: national department of health 2019. available from: https://www.statssa.gov.za/publications/report%2003-00-09/ report%2003-00-092016.pdf (accessed 8 march 2018). 13. draper ce, tomaz sa, hinkley t, et al. cross-sectional associations of physical activity and gross motor proficiency with adiposity in south african children of pre-school age. public health nutr 2019;22(4):614-623. [doi: 10.1017/s1368980018003579] [pmid: 30585555] 14. tomaz sa, prioreschi a, watson ed, et al. body mass index, physical activity, sedentary behavior, sleep, and gross motor skill proficiency in preschool children from a lowto middleincome urban setting. j phys act health 2019;16(7):525-532. [doi: 10.1123/jpah.2018-0133] [pmid: 31154894] 15. tomaz sa, jones ra, hinkley t, et al. objectively measured physical activity in south african children attending preschool and grade r: volume, patterns, and meeting guidelines. pediatr exerc sci 2020; 32(3): 150-156. [doi: 10.1123/pes.2019-0216] 16. tomaz sa, jones ra, hinkley t, et al. gross motor skills of south african preschool-aged children across different income settings. j sci med sport 2019;22(6):689-694. [doi: 10.1016/j.jsams.2018.12.009] [pmid: 30606626] https://www.statssa.gov.za/publications/report%2003-00-09/%20report%2003-00-092016.pdf https://www.statssa.gov.za/publications/report%2003-00-09/%20report%2003-00-092016.pdf original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license nutritional supplements use, cost, source of information, and practices by johannesburg north gym goers y coopoo,1 dphil, facsm; x mccreanor,1 mphil sport science; g gabriels,2 phd 1 department of sport and movement studies, faculty of health science, university of johannesburg, gauteng, south africa 2 department of pharmacy and pharmacology, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: g gabriels (gary.gabriels@gmail.com) in the area of nutritional supplements in general, the earlier work of muller and krawinkel indicates the extent of research that has been undertaken in the area of nutritional supplements.[1] nutritional supplements refer to any product that is generally intended to supplement the diet when taken by mouth as a pill, capsule, tablet, or liquid. the specific definition and categorisation is often grey, thus leading to definition complexity.[2] currently, the use of nutritional supplements is on the increase worldwide, predominantly in western countries, but is also expanding to other parts of the world, including south africa. [1] this is substantiated by the nutritional supplement sales figures for what now is a multibillion dollar global industry [2,3,4] projected in 2015 to be us$ 93.15 billion.[3] the work of starr and others provides evidence that the exposure to nutritional supplements in other parts of the world has been via advertisements, including print and internet advertisements, and infomercials. [5] this pattern is also found in south africa. dodge and jaccard provide links to the various forms of advertising [5] marketing and use of nutritional supplements, showing that exposure at an early age, such as, by adolescents [6], are factors that influence a behavioural intention for steroid users.[5,6] the use of performanceenhancing and/or appearance substances in young adulthood. [2,5,7] is often a gateway to the use of more harmful and illicit substances, to achieve desired outcomes. [7] recent work has also shown that the marketing practices of supplements is often dishonest and that many of the claimed benefits have little or no scientific supporting evidence [7] of product safety and efficacy. approval from regulatory bodies has often not been obtained before marketing the supplements. [2] further, unless the consumer has been found to have a nutrient deficiency, nutritional supplementation consumption may not improve the deficiency but may rather have detrimental effects on the consumer’s health. [2]. in competitive sport, factors such as nutritional supplement consumption, can be a contributory factor in the determination of the results of sporting contests [2]. for the gym user, particularly with endurance exercise training, nutrition plays an important role with regard to performance. [8] in the work by morrison et al. that surveyed persons who exercised regularly at a gym, they showed that a majority of the gym users (85%) took supplements for the purpose that the product is intended and not for any potentially prohibited substances that may be in background: nutritional supplements are defined as any dietary supplement manufactured product that is generally intended to supplement the diet when taken by mouth as a pill, capsule, tablet, or liquid. currently, the use of nutritional supplements is on the increase worldwide, predominantly in western countries but also more recently expanding to other parts of the world for what has become a multibillion-dollar global industry. as a result, consumer demand has caused the increase in the advertising and marketing of these products. this contributes to early exposure to nutritional supplements by potential consumers and is an influencing factor for the use of performance-enhancing and/or appearance substances by adolescents. for the nutritional supplement industry the container is thus the manifestation of innovative ideas for the enterprising business-minded mogul. for the consumer, body image and ideal body discrepancy, and social influences manifest in the belief that the perfection of body development cannot be achieved without the use of nutritional supplements. this makes the consumer a captive audience for the industry and a challenge for the health care provider when suggesting alternatives to nutritional supplements, based on costbenefit, and risk assessment. objective: to determine the association between commercial gym goers and nutritional supplements, in particular the commencement of use, reasons and purpose for use, and the financial and risk implications of use. methods: a self-administered questionnaire based on a cross-sectional quantitative design and systematic convenience sampling was given to the 364 recruited males and female gym goers. results: this study’s finding shows that the main reasons why females attend gyms are for muscle gain (57%), weight loss (48%), staying healthy (47%), and a ‘spiritual motive’ (39%) in males, it is predominantly for muscle gain (54%). protein supplements were the most popular products that were consumed (84%) followed by carbohydrates (72%) and vitamins (71%). it was found that the consumption of nutritional supplements often starts at high school age and continues into adulthood. the analysis shows that natural source protein products are better priced than nutritional supplement products. conclusion: the study shows the importance of educating gym goers, the general public, and the guardians of minors to make a behaviour change towards nutritional supplement consumption. the change should also incorporate a cost-benefit risk assessment which is practical for the consumer when comparing supplement use as alternative sources of protein. keywords: alternative protein, body image, cost, gender, spiritual motives s afr j sports med 2020;32:1-6. doi: 10.17159/2078-516x/2020/v32i1a6771 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a6771 https://orcid.org/0000-0001-7446-9176 https://orcid.org/0000-0001-5148-1607 https://orcid.org/0000-0003-0693-9214 original research sajsm vol. 32 no. 1 2020 2 the supplements. many consumed multivitamins (45%), protein shakes (42%), vitamin c (35%) and vitamin e (23%) at least five times per week. [9] according to fitzgibbon et al. teenagers’ body image discrepancy and social influences were among the reasons for the use of supplements. [10] the use of supplements by female users was based on body dissatisfaction and the aspiration to be thinner. on the other hand, male users indicated that they required the use of supplements in order to develop their muscles. [11] therefore the use of these supplements and their intended value may have shifted in the context of the gym goers’ desires and aspirations by today’s standards. this may indicate that for gym users the ideal body is not achievable unless they use nutritional supplements. [10] the impact of this shift is considered to be a potential health risk to the user due to the non-declaration of all ingredients on the product’s label and the associated lack of warnings and side effects included with product information. [12] in order to provide the gym user with an alternative approach to supplement use [7], the study uses protein requirements to illustrate the cost-benefit and risk assessment of a product. the aim of this study was therefore to assess, in the johannesburg north region of south africa, gym goers’ reasons for going to the gym, the specific nutritional products consumed by these users, and the monthly cost to attain their personal goals and needs. methods participants and study design the study was conducted in the johannesburg north region of south africa at five selected and reputable gyms. the recruitment for this study only focused on adult gym members of 18 years and above. the study’s design was a quantitative cross-sectional design as described by graziano and raulin [13], using a questionnaire that allowed for multiple responses as the data were collected and validated based on a study undertaken by gradidge [14]. the sample size was computed, based on the work of sekaran (1992)[15] the sampling method used was a systematic convenience sampling method consisting of male and female gym goers who attended the gym twice or more times per week as presented in an earlier study by mc creanor et al.,.[16] the questionnaires were personally administered by the researcher and were available to provide clarification to the participants if necessary. the process of recruitment involved a random selection, that is, by asking every third person entering the gym whether they would be willing to volunteer for the study. refusal to participate meant the subsequent person was asked and thereafter the recruitment process reverted again to every third person. in this study, protein supplements are defined as commercially available products marketed by the manufacturers to provide for a claimed human nutritional deficiency. natural source protein is acquired, often as whole food, of plant or animal origin. spiritual motives relate to the feeling or belief that there is a person’s training is not only for the physical aspects derived from training, but that there is also a mental or spiritual feature that is also achieved. in the context of the consumption of nutritional supplements, the theory of attitudes, namely, the functionalist theory by the psychologist daniel katz was used as a guideline in this study. [17] the theory is formulated by its functions, and articulates why people hold on to certain attitudes which may assist them in attaining their basic goals and needs. [17] questionnaire approach and methodology the questionnaire’s content for this study specifically covers, (i) reasons for attending a gym by means of gender, (ii) nutritional supplement consumption by gym users, (iii) age of first consumption of nutritional supplements, (iv) the monthly cost of supplements, and (v) examples of nutritional protein containing supplement products. it covers aspects not previously published by the researchers mc creanor, et al. related to this study. study participants were assured of confidentiality, prior to their providing research consent. the participants’ selfadministered questionnaires were numbered but remained anonymous. the questionnaires were approved by the university of johannesburg, faculty of health sciences research ethics committee (rec-01-144-2015). statistical analysis data for the study were manually transcribed and independently validated using the windows-based microsoft ® office excel 2003 sp 1 (excel © 1985-2003 microsoft corporation). the statistical package for the social sciences (spss inc. version 16) was used to calculate the descriptive and inferential statistics. the respective results are presented as percentages. results the age of the gym goers in the johannesburg north area ranged between 18-49 years (mean 27 years). of the total of 364 table 1. reasons for attending gymnasium by gender (n= 364) male n=205 (56%) female n=159 (44%) sport/exercise type mainly (%) sometimes (%) never (%) mainly (%) sometimes (%) never (%) muscle gain 54 32 14 57 17 26 weight loss 25 50 25 48 32 20 swimming 24 51 25 39 41 20 body conditioning 29 50 21 43 35 22 aerobic exercise 17 53 30 44 34 22 specific training 25 44 32 40 36 24 spiritual motive 24 37 39 39 36 25 staying healthy 28 40 32 47 36 17 cross-fit training 33 39 28 40 32 28 % indicates percentage of respondents. original research 3 sajsm vol. 32 no. 1 2020 participants, 205 (56%) were male and 159 (44%) were female. the main reasons for attending the gyms as presented in table 1 (multiple responses), show that female participants in the study indicated and based on the percentage response was for muscle gain (57%), weight loss (48%), and staying healthy (47%). for the male participants in the study, the main reasons for attending the gym and based on percentage response were for muscle gain (54%), cross-fit training (33%), and body conditioning (29%). further, a larger percentage of male participants in the study who stated, ‘sometimes’ for reasons for attending a gym indicated the need for aerobic exercise (53%), and swimming (51%). table 2 contains information provided by the participants on supplement use. these are protein supplements (84%), carbohydrates (72%), and vitamins (71%). supplements that were consumed to a lesser extent by the study cohort were phedra-cut thermogenic aids (35%), branched-chain amino acids (bcaa) (34%), and l-glutamine (33%). table 3 illustrates the age of the study's participants first use of nutritional supplements. of the cohort (n=216), (60%) (n=130) indicated that they commenced using nutritional supplements between the ages of 13to 18-years-old (high school level), (23%) (n=49) between the ages 10to 12years-old (primary school level), and (17%) (n=37) were over 18-years-old when they joined the gym. of the total of 362 respondents, 48% (n=174) ‘sometime’ read the label’s information, 41% table 2. nutritional supplement consumption by gym users (n = 364) supplement yes (%) no (%) protein supplements (e.g. whey protein) 84 16 carbohydrate supplements (e.g. energade, powerade) 72 28 vitamins (a, b, b12, c, d and e) 71 29 creatine supplements (e.g. creatine monohydrate) 67 33 caffeine (e.g. redbull, guarana) 59 41 fish oil (e.g. omega 3 tablets) 37 63 cla (conjugated linoleic acid) weight loss supplements 36 64 phedracut thermogenic aid 35 65 branched-chain amino acids (bcaa) 34 66 l-glutamine 33 67 % indicates percentage of respondents. table 3. age of first consumption of dietary/nutritional supplements (n = 216) age (years) institution participants (n) participants (%) 10-12 primary school 49 23 13-18 high school 130 60 over 18 when joining gymnasium 37 17 table 4. monthly cost on supplements (n=222) category of spending (rand) participants (n) participants (%) 0 500 54 24 501-1000 58 26 1001-1500 51 23 1501-2000 34 15 20012500 20 9 2501-3000 3 2 >3001 2 1 table 5. examples of nutritional protein containing supplement products and cost retail pharmacy protein source claimed estimate % of protein in product ** cost per 100 gram of product (rand) * estimate cost per 100 gram of protein (rand) biogen pro series bites (code:176972000ea) 27 71 265 real thing pro protein (code: 060822000ea) 95 149 157 usn pure protein nutritional bars (code: 154116003ea) 27 40 147 usn trust protein nutritional bars (code: 187675001ea) 38 50 131 npl 100% whey protein isolate supplement (code: 190883001ea) 83 53 64. evox 100% casein protein supplement (code: 082011000ea) 90 49 54 npl whey protein supplement (code: 176978001ea) 67 32 48 evox synergy whey protein supplement (code: 153794006ea) 77 30 39 primal nutrition whey protein (code: 187183001ea) 65 24 37 evox synergy whey protein cookies (code: 066133000ea) 77 27 35 future life high protein (code: 167580001ea) 30 10 32 biogen pro series nitro protein supplement (code: 105586000ea) 77 32 25 * cost as assessed in february 2018 retail pharmacy (dischem) https://www.dischem.co.za/search/?q=protein+supplements. accessed 24th july 2019. ** https://www.predatornutrition.com/articlesdetail?cid=9-cheap-sources-of-protein https://www.dischem.co.za/search/?q=protein+supplements original research sajsm vol. 32 no. 1 2020 4 (n=149) ‘always’ read the label’s information, and 11% (n=39) ‘never’ read the label’s information for nutritional value, benefits and side effects. table 4 illustrates the monthly spend (in south african rands) on performance-enhancing supplements by the study’s participants. of the study’s participants (n=222), 26% (n=58) indicated that they spent between r500 to r1000 per month on nutritional supplements at the time of the study. twenty-four percent (n=54) spent up to r500, 23% (n=51) spent between r1000 to r1500, 9% (n=20) spent between r2000 to r2500, 2% (n=3) spent between r2500to r3000, and 1% (2) spent than r3000 per month. tables 5 and table 6 respectively provide a comparative illustration of protein-containing dietary/nutritional to that of ‘natural protein source’ products. discussion the study was focussed on assessing johannesburg north gym goers’ reasons for going to the gym, their specific nutritional product consumption, and the monthly cost to attain their personal goals and needs. the demography of the study’s participants ranged between 18-49 years (a mean of 27 years). of the total of 364 participants, 205 (56%) were male and 159 (44%) were female.[16] the study data (table 1) show that females were more ‘certain’ with their reasons for attending the gym, than males based on the sport/exercise type that were provided as options in the questionnaire. the main reasons (table 1) for female participants in the study to attend the gym indicated with ‘certainty’ were for muscle gain (57%) and weight loss (48%). male participants indicated with ‘certainty’ that their reason for attending the gym was for muscle gain (54%). this finding concurs with senekal et al, [7] which indicated that supplement use and exercising by younger men seem to focus on muscle building/strength and fitness. [7, 18] further, this study shows that the female participants (39%) had a ‘spiritual motive’ for attending the gym compared to males who indicated that they ‘never’ had such a purpose. table 2 shows that of the overall cohort of gym patrons, 84% of the participants indicated that they consume protein supplements, followed by carbohydrates (72%), and vitamins (71%). of the supplements that were consumed to a lesser extent by the study’s cohort was phedracut thermogenic aids (35%), branched-chain amino acids (bcaa) (34%), and lglutamine (33%). this study’s findings concur with those of jonvik, et al. [8] which showed an increasing interest in the role of protein ingestion during and after endurance exercise to support physiological training adaptations [8]. the use of protein supplements is an important finding for the overall cohort, and can be associated with the muscle gain requirement as shown in table 1 for both male and female participants. two hundred and nineteen (60%) of the participants indicated that they started using nutritional supplements between 13-18 years (high school), 84 (23%) between 10-12 years (primary school), and 62 (17%) were over 18 years old (table 3). these results indicate how early in life supplements were used and continued into adulthood, concurring with the findings of [2,7] relating to the prevalence of supplement use. [2,7]. this shows the impact and attraction that nutritional supplements have on adolescents. further, as in the work of gabriels et al. [3] it shows that certain products have age restriction consumption on the product’s label, but which may be disregarded by both the consumer and the supplier through ‘aggressive’ marketing practices. [19] as published in a previous work by mc creanor et al. [17] the main sources of information regarding nutritional supplements were the internet (75%), pharmacists (67%) and books (66%). the provision of information on supplements which was least accepted by the respondents was from parents (38%), siblings (37%), physicians (36%), and biokineticists (34%). the study by van der walt and coopoo [20] also identified pharmacists as a main source of this information.[20] contrary to this study’s findings, the research of gabriels and lambert [19] showed that (43%) of their respondents where not influenced by information on nutritional supplements provided by pharmacists, dieticians, nutritionists and doctors. [19] instead, 24% of respondents indicated that they were influenced by information provided by the coach, gym and/or fitness trainer, and fellow athletes. [19] what the various studies show is that information acquisition is changing rapidly. [16,20] this is all the more important for continuous research practice, on how information-gathering occurs to ensure the reliability of information provided in the interest of the well-being of the consumer. out of the total of 362 respondents, 48% (n=174) ‘sometimes’ read the label’s information, 41% (n=149) ‘always’ read the label’s information, and 11% (n=39) ‘never’ read the label’s information for a product’s nutritional value, benefits and side effects. the study by gabriels and lambert [19] showed that with particular emphasis on moderately physically active and table 6. example of ‘natural sources’ of protein containing products (alternative) and cost retail market protein source claimed estimate % of protein in product cost per 100 gram of product (rand) * estimate cost per 100 gram of protein (rand) tofu 8 14 170 nuts 20 30 150 hemp powder 45 61 136 sardines 25 21 84 beef 26 13 51 milk 3.4 2 44 eggs 13 4 34 chicken 31 6 19 peanut butter 25 5 19 beans 21 4 17 * cost as assessed in october 2018 retail market (pick ‘n pay) original research 5 sajsm vol. 32 no. 1 2020 competitive participants, close to 70% of the respondents who purchased supplements were strongly influenced by label’s information, specifically that the product should to be free of banned substances and be of a high quality. [19] whilst this may be true for the particular cohort studied, what is undeclared on the label’s content (e.g. steroids) may be the ‘driver of consumption’, knowingly or unknowingly. [19] this ‘driver of consumption’ will assist in attaining the gym user’s personal goals and needs, which is in line with the functionalist theory of psychologist daniel katz. [17] table 4 illustrates the monthly costs at the time of the study (in south african rands) on performance-enhancing supplements by study participants who attended the johannesburg north gym. of the study’s participants (n=222), 26% (n=58) indicated that they spent between r500-r1000 per month on nutritional supplements at the time of the study. twenty-four percent spent up to r500, 23% spent between r1000-r1500, 9% spent between r2000-r2500, 2% spent between r2500-r3000, and 1% spent more than r3000. thus a sizable proportion based on the first three categories (table 4), account for 73% of the study participants who spent about r1500 or less per month on nutritional supplements. recent evidence suggests that the protein requirements of well-trained endurance athletes, performing at high levels of endurance exercise training may be greater than previously assumed. [8,10] gym users see people with their desired body image and often, without considering the consequences, go to great lengths to achieve these goals. the fear of not being able to achieve the goals contributes to changing their behaviour towards the use of performance-enhancing supplements, even though they are opposed to the idea of taking these supplements. [17] hence, many gym users in this study support this growing market. this is notwithstanding that this behaviour may steer gym users in the wrong direction, as taking these supplements may not necessarily be best for their health and well-being. [17] table 5 and table 6 illustrate the use of protein-containing nutritional and natural source products. natural source protein-containing products, such as chicken, peanut butter, and beans (table 6) are cheaper per 100 grams of protein than the nutritional supplement products (table 5). the work of nowson and o’connell [21] indicates that for a subject weighing 72 kg, the recommended daily allowance (rda) for protein is 58–86 grams per day. [21] to maximise muscle protein accretion with resistance exercise, the daily protein intake should be approximately between 115 -158 grams in order to retain lean body mass during weight loss protein intakes of 167–223 grams have been advocated. [21] based on these respective categories and levels of activity, protein recommendation could be attained cost-effectively (table 6) via non-nutritional supplement products. nowson and o’connell [21] states that additional protein intake is unnecessary if a balanced diet is followed. [21] on the contrary, excessive consumption of protein can produce toxic effects that may lead to health problems, such as kidney disease, water retention and high levels of ketones in the body. this reinforces the work of senekal et al [7] that comment on the wide use of supplements, especially protein, emphasising the need for dissemination of consistent, evidence-based information on supplement recommendations and risks. [7] regarding a shift of protein source from supplements to nonsupplement sources, there can be a change in behaviour according to katz [17], when it no longer assists its function and the individual feels unfulfilled. [17] gym users may thus change their attitude towards nutritional supplements, if they are aware of the health risks involved in consuming these supplements. [2,17] the approach that is suggested for behaviour change is not so much as a result of the change in the information provided but rather by altering a person's primary motivational and personality needs.[17] body image or dysmorphia appears to be a major motivating factor for taking nutritional supplements for the non-sporting gym goer. study limitations the main limitation in all similar studies is poor memory and truthfulness from participants. in the context of this study, there may be possible under/over estimation of the actual amounts spent on nutritional supplements as provided by the study participants. the estimate of protein content in respective products is based on the information assessed from the different sources as presented in table 5 and table 6. conclusion the study of johannesburg north’s gym goers has shown that the gender-specific reasons for attending the gym were for females, muscle gain, weight loss, and staying healthy; while for males it was muscle gain. a further finding was the ‘spiritual motive’ for attending the gym for females, compared to that of males who did not declare such a motive. protein supplements were the most popular of supplements consumed by the participants. the study further shows that a sizeable proportion of participants commenced consumption of nutritional supplements at high school age, with an increasing number starting at primary school level. the main sources of information on nutritional supplements were the internet, pharmacists and books. only forty-one percent of the participants always read the label information. the monthly amount spent on nutritional supplements accounted for by seventy-three percent of participants about r1500 or less. this study’s findings further show that natural whole food sources of protein-containing products are cheaper than other nutritional supplements. it is important to do a costbenefit risk assessment that is practical for the consumer. it is also necessary to check whether any undesirable contaminants are present in the supplement products. it is important to educate gym users, the general public, and the guardians of minors regarding nutritional supplement consumption and their effects. recommendations statutory bodies, such as the south african drug-free sport (saids), should embark and improve on education and awareness campaigns related to nutritional supplements, original research sajsm vol. 32 no. 1 2020 6 based on early age of first consumption as observed in this study. relevant subject matter on the potential harms of nutritional supplement consumption should be included in the school curriculum. improvement of enforcement capacity with respect to the violation of a label provision by manufacturers, distributors and retailers, needs to be accelerated, with concomitant media exposure. gyms should offer educational classes to their patrons that focus on non-supplement-based alternative protein sources, which provide a reduced risk of contamination. future research the findings in this study show that female participants had a ‘spiritual motive’ for attending the gym compared to males. thus exploring via self-administered questionnaire(s) in detail and depth, the link related to this ‘spiritual motive’ and the consumption or non-consumption of nutritional supplements would be useful. in order to get improved information and data on nutritional supplement consumption and the monthly costs, it would be important to gather this information at the point of sale of retail outlets, and make it available to the gym user. knowledge of multiple nutritional consumption/combination categories, as well as genderspecific consumption would expand the relevance of the information from this study. the best approaches to provide knowledge and education pertaining to all aspects of nutritional supplements to younger age groups needs to be determined, as has been observed in this study. conflict of interest: the authors declare that they have no conflict of interest. acknowledgements: gary gabriels is a recipient of research grants from the south african medical research council, the south african national research foundation, and forms part of a research team that receives national institute for humanities and social science support. author contributions: yc contributed to the design of study, interpretation, presentation and editing of paper. xm contributed to the design, data acquisition and analyses. gg contributed to the design, data collection, data acquisition and analyses, interpretation and presentation, the drafting, and the main writing to the paper. references 1. müller o, krawinkel, m. malnutrition and health in developing countries. can medassoc j 2005; 173(3), 279-286. 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[doi:10.1023/b:sers.0000049229.93256.48] 12. dodge tl, jaccard jj. the effect of high school sport participation on the use of performance-enhancing substances in youth adulthood. j adolesc health 2006; 39(3): 367-373. [doi: 10.1016/j.jadohealth.2005.12.025] 13. graziano am, raulin ml. research is a process of inquiry. in: research methods: a process of inquiry, 4th ed 2000; allyn and bacon: 28-53. 14. gradidge pj-l. the use of performance enhancing substances by adolescent male athletes in selected johannesburg boys’ high schools. unpublished master’s thesis. university of witwatersrand, 2010. http://wiredspace.wits.ac.za/hndle/10539/9001 (accessed 15th june 2017) 15. sekaran u. research methods for business: a skill-building approach. 2nd ed. new york: wiley, 1992: 253 16. mc creanor x, coopoo y, gabriels g. attitudes towards nutritional supplement use amongst adult gymnasium users in johannesburg north. s afr j sports med 2017; 29:1-5. [doi: 10.17159/2078-516x/2017/v29i0a1387] 17. katz d. the functional approach to the study of attitudes. public opin q 1960; 24(2),163-204.[ doi:10.1086/266945.] 18. schönfeldt hc, hall n, pretorius b. 12th ifdc 2017 special issue – high protein sports supplements: protein quality and label compliance. j food compost anal2019; 83:103293 [doi.org/10.1016/j.jfca.2019.103293] 19. gabriels g, lambert m. nutritional supplement products: does the label information influence purchasing decisions for the physically active. nutr j 2013; 12:133 [doi:10.1186/14752891-12-133] 20. van der walt v, coopoo y. a survey of the attitudes and knowledge of parents of high school children on the east rand on the usage of nutritional supplements. s afr j sports med 2016; 28: 74-78. [doi:10.17159/2078-516/2016/v28i3a1674] 21. nowson c, o’connell s. protein requirements and recommendations for older people: a review. nutrients 2015, 7(8):6874-6899 [doi: 10.3390/nu7085311] https://doi.org/10.1123/ijsnem.14.4.481 https://doi.org/10.1016/j.jfca.2019.103293 https://doi.org/10.3390/nu7085311 sajsm editorial.indd sajsm vol. 26 no. 3 2014 67 healthy active kids south africa: how do we score? �e healthy active kids south africa (haksa) was initiated in 2007 by prof. vicki lambert of the university of cape town, south africa (sa). �e idea arose a�er she attended an international conference on physical activity and obesity in children in toronto, canada, and witnessed the impact that the release of the healthy active kids canada report card had in that country. on her return, she garnered the support of nine enthusiastic scientists from six tertiary academic institutions in sa, convinced discovery vitality and the sports science institute of sa that it was a worthwhile project to support, and together they produced the �rst haksa report card. although this created media interest, it did not really translate into concerted action. undeterred, the group repeated the exercise in 2010 – this time, there were 18 academics representing 10 institutions and ngos. �e scope was widened to include peer-reviewed literature, dissertations and government reports. �e uptake this time was more promising, and the focus of the report was directed more toward intersectoral policies and programmes to try to e�ect change. in 2014, as part of the global summit on physical activity and children, the team repeated their e�orts, this time with 21 scientists from 15 academic institutions and ngos. �e additional outcomes of the 2014 report included an advocacy document and a peer-reviewed manuscript. �e impact of the report is also going to be evaluated. �ere are many good stories coming out of this initiative. firstly, sa is one of 15 countries around the world that has started evaluating the world in which our youth live. five of the countries are from africa. secondly, it seems that the outcomes of this report have pressed the right buttons, with promising signs that national, regional and local government along with ngos have taken note and are starting to talk about ways in which they can contribute to raise the overall rating (we slid from a c– in 2010 to a d grade in 2014). �e report has also exposed many causes for concern – all the members of the sa sports medicine association (sasma) should take note because many of these areas are covered by the varied scope of practice of sasma members. for example, almost half the children studied are insu�ciently active, getting <1 h/day of physical activity. sedentary behaviour remains a problem, with children spending just under 3 h/day watching television (we are nearly bottom of the list for this category compared with the other 14 countries). overweight and obesity continue to increase, possibly linked to the fact that over two-thirds of adolescents consume fast foods at least three times per week. �ere is also a progressive increase in the consumption of sugarsweetened drinks. however, it is not all doom and gloom. we achieved a high score (b) for the national school nutrition programme, where the reach has improved and more children are bene�tting from the programme. we also scored a b for the category of government strategies and investments, where it is evident that programmes have been developed to increase physical activity among children through various policies and investments. it just may take some time to realise the bene�ts of these investments and programmes. �e report emphasises that much can be done to improve the health and wellbeing of our youth. changes can be implemented at the level of the family, the community in which the child lives and in the school environment. �e report has identi�ed the weaker areas; now it is going to take creative thinking and a willingness to get involved to make a di�erence. every health professional in the country should read the report; there is no doubt that a�er reading it there will be a heightened awareness of the problem areas. �e challenge thereafter is to embrace a problem area and try to make a change – a small change made by everyone will have a much bigger impact than a large change made by a few. �e full report can be viewed on the website of the sports science institute of sa website (http://www.ssisa.com). mike lambert editor-in-chief s afr j sm 2014;26(3):67. doi:10.7196/sajsm.575 editorial 100 sajsm vol 19 no.3 2007 to the editor: we would like to comment on the review article by shuttleworth-edwards et al. 'ethically we can no longer sit on the fence – a neuropsychological perspective on the cerebrally hazardous contact sports', published in the july edition of your journal. overall, this article is well researched and written. however, as well as highlighting a number of important observations made in this article, we would like to emphasise the progress that has been made in developing a communitybased return-to-play concussion programme in south africa, thus illustrating that a high level of care can be sourced for patients with concussion wishing to return safely to collision and contact sports. 1. it must be noted that computerised and detailed neurocognitive assessment has no role to play in the prevention of head injury in sport. athletes participating in contact or collision sports are at risk of head injury and the role of mouthguards and headgear is controversial in head injury prevention. neurocognitive assessment does, however, form a component of the return-to-play management of the injured patient. 2. due to a paucity of clinical signs, concussion management and return to play must focus on the cognitive, emotional and behavioural effects of the injury, emphasising again the significant individual variation to this injury. it is also well illustrated how gender differences too are an important consideration, in addition to underlying genetic factors. we would agree with the authors that attributing the social ills of society to mild traumatic brain injury on a cause and effect basis would not be reasonable. 3. the cognitive reserve theory could be a reasonable way of explaining the individual variant in recovery time after injury. 4. we have refined our clinical approach, based on research and our experience in managing this injury that encompasses individual differences in response to concussion. by focussing on serial symptom analyses, clinical evaluations, neurocognitive testing – both computerised screening and detailed clinical assessments – and then finally an exercise challenge, we believe we would be in the best position to support a decision for the patient to return to sport. the third component of exercise challenge has been very important and provides support for the ‘hypoxic theory’ as detailed by ewing et al. 1 the proposal of informed consent is an excellent one and should be incorporated into any sports education programme and certainly into a return-to-play concussion programme. 5. finally, and most importantly, we wish to illustrate that, as sports physicians who come into contact with mild traumatic brain injury on a weekly and often daily basis, we believe that we are incorporating the latest in international clinical consensus 5-7 together with computerised neurocognitive assessments and individualised returnto-play guidelines in a cost-effective, pragmatic model. in the last 3 years, we have developed a community-based concussion programme, incorporating satellite return-toplay concussion centres, under the banner of the pharos schools concussion programme and sports concussion south africa. 2-4 the programme has a number of equally important foci: • education – this we believe to be key; if the sporting public are aware of the significance of concussion and its potential consequences, we believe the risks to be significantly reduced; to this end, the website www.sportsconcussion. co.za has become the central reference tool aiming at educating the public and medical fraternity alike; in addition we have a concerted programme of lectures to schools and clubs aimed at educating pupils, parents and coaches; a campaign to utilise various media including the press, radio and television is also launched annually at the beginning of the schools’ rugby season; at this stage of the season we would also introduce the concept of computerised neuropsychological testing and stress the significance of obtaining baseline data. • acute management – identifying a concussed player, removing them from the field of play and conducting an initial analysis are important first steps; the pharos programme incorporates this by distributing modified versions of the sports concussion assessment tool (scat) to participating schools; the helpline 084-brain24 launched in conjunction with an emergency service call centre advises as to where to obtain medical assistance and the importance of clinical follow-up. • serial clinical assessment – once a case of concussion has been identified, this is an essential step in determining return to play; players undergo a thorough symptom analysis and trends in symptom resolution are tracked; a neurological assessment including verbal cognitive and balance tests is conducted; finally, if appropriate, computerised neuropsychological tests are conducted and compared with baseline or age-appropriate norms; we concur with the view of the american college of sports medicine that computerised neuropsychological testing is desirable in concussion management rather than essential; 7 moreover, contrary to shuttleworth-edwards and whitefields’ assertion that ‘for best practice in the implementation of return-to-play … decisions… registered psychologists are called for…’, we believe this to be impractical, both due to the scarcity and inaccessibility of such resources and the fact that computerised test batteries are designed for team physicians to implement and integrate into their management protocol of a concussed player. 8 ethically we can no longer sit on the fence? letters to the editor pg100-104.indd 100 10/3/07 3:30:21 pm 100 sajsm vol 19 no.3 2007 sajsm vol 19 no.3 2007 101 • return-to-play – this is conducted in a progressive fashion using graded exercise stress to confirm complete resolution of pathology before full sports participation; again the progress will be individualised and poor prognostic indicators such as previous concussions and co-morbid pathology taken into account. in summary, we acknowledge the impetus that computerised neuropsychological testing has given to sports concussion management and research. realistically and practically though, this can only form one part of a clinically orientated serial assessment of the concussed athlete that takes cognisance of both those that have access to this facility and the many (particularly in south africa) that don’t. as sports physicians we see ourselves as foot soldiers in the educational drive and clinical facilitation process of managing mild traumatic brain injury in sport. we are determined to drive a nationally focussed programme of international calibre. the last thing we will do is sit on the fence. ryan kohler jon patricios sports concussion south africa and pharos schools concussion programme: cape town and johannesburg 1. ewing r, mccarthy d, gronwall d, wrightson p. persisting effects of minor head injury observable during hypoxic stress. j clin neuropsychol 1980; 2: 147-55. 2. kohler r. the management of concussion in rugby football: an update. s afr j sports med 2003; 15(1):16-20. 3. kohler r, jakoet i, mandrja s. south african rugby guidelines on the management of concussion. s afr j sports med 2003; 15(1): 26-28. 4. kohler r. concussion in sport – practical management guidelines for medical practitioners. cme march 2004. 5. aubry m, cantu r, dvorak j, et al. concussion in sport group. summary and agreement statement of the first international conference on concussion in sport, vienna 2001. recommendations for the improvement of safety and health of athletes who may suffer concussive injuries. br j sports med 2002, 36: 6-10. 6. mccrory p, johnston k, meeuwisse w, et al. summary and agreement statement of the second international conference on concussion in sport, prague 2004. br j sports med 2005; 39:196-204. 7. herring s, bergfield ja, boland a, concussion (mild traumatic brain injury) and the team physician – a consensus statement. s afr j sports med 2005, 37 (11):2012-2016. 8. collie a, maruff p. computerised neuropsychological testing. br j sports med 2003; 37: 2-3. to the editor: we appreciate the response of sports physicians kohler and patricios to our review article ‘ethically we can no longer sit on the fence: a neuropsychological perspective on the cerebrally hazardous contact sports.’ 8 they have clearly articulated a position in respect of optimal concussion management that in broad terms is highly commensurate with the recommendations arising out of our review. abreast of our own country-wide initiative, we are strongly supportive of their determination ‘to drive a nationally-focussed programme of international calibre’. indeed we are aware that they are providing a crucial educative role concerning the utility of computerised neuropsychological testing and the importance of obtaining baseline data in the south african sports concussion arena. the last thing they are doing is sitting on the fence. there is, however, a contentious issue raised by these practitioners that warrants further elaboration, and where we consider there has been a level of misrepresentation. kohler et al. state that 'contrary to shuttleworth-edwards and whitefields’ assertion that “for best practice in the implementation of return-to-play … decisions… registered psychologists are called for…”, we believe this to be impractical, both due to the scarcity and inaccessibility of such resources and the fact that computerised test batteries are designed for team physicians to implement and integrate into their management protocol of a concussed player.’ in response to the above we suggest as follows: 1. the manner in which we have been cited implies that registered psychologists are claiming a central role in return-to-play decisions per se, whereas we only claim more specifically to provide an important contribution to the decision via expertise in psychometric testing. we are entirely in agreement that computerised test batteries only form part of a clinically-oriented assessment of the concussed athlete by a medical doctor who makes the overall management recommendation. this is clear if our statement is cited more appropriately in full as follows: ‘for best practice in the implementation of such returnto-play and termination decisions using computerised psychometric instruments, registered psychologists with training in clinical neuropsychology are called for, and have an important complementary role to play’ (p. 37, new emphasis added). 2. in light of the broad infrastructure of our own national sports concussion initiative (nsci), we do not believe that a scarcity of psychological resources for the purposes optimal application of neurocognitive testing in concussion management: a professional dilemma pg100-104.indd 101 10/3/07 3:30:21 pm 102 sajsm vol 19 no.3 2007 of facilitating concussion management can be claimed within the south african context. furthermore we do not consider this to be a sound professional basis on which to argue for failure to employ an appropriate resource. 3. whereas computerised test batteries are certainly designed for team physicians to integrate into their management protocol of concussed athletes, we believe that to suggest that they are also specifically designed for team physicians to implement is highly problematic. this raises a professional dilemma in need of further elaboration, as follows. professional parameters in the implementation of computerised neuropsychological assessment on the one hand there is the argument presented by collie and maruff 2 that has been reiterated in the kohler et al. letter to the editor, in which it is suggested that neuropsychologists are not necessary to interpret the results of automated computerised reports derived in sports concussion context. a core basis for this claim is the rationale that, because exceedingly large numbers of athletes need to be evaluated, it is not practical to involve neuropsychologists exclusively. implicit in this line of reasoning, which, from the professional standpoint, is highly questionable, is that neuropsychologists are in relatively short supply and/or that their services are too expensive and will render this kind of assessment unaffordable. it is of interest that in contravention of this argument, an earlier paper by collie et al. 1 suggests that one of the most attractive features of the computerised cognitive tests in the sports context is that they allow for the possibility of electronic submission of data in a matter of seconds, and hence those data may be collated and interpreted by a deskbound neuropsychologist for immediate interpretation and resubmission back to a trainer or physician at a sporting arena in a matter of minutes. indeed, we are providing concussion management for a leading uk soccer team on this basis! in contrast to those who suggest that computer-based tests circumvent the need for neuropsychologists, others have expressed concern about the potential for misuse of neuropsychological tests with psychometric properties if they become separated from their professional – i.e. neuropsychological – source. 6 it is pointed out that the ease with which computerised tests can be administered, and automatic reports generated, may cause non-psychologists to fall into the trap of construing that the scores derived can be used simplistically as a type of ‘yes’ or ‘no’ litmus paper test for making decisions about the presence or absence of cerebral dysfunction in the individual case, with the potential for misdiagnosis. with this attitude there is a danger of reverting to the dark ages of an early actuarial approach to neuropsychological evaluation that has subsequently been abandoned in favour of a syndrome analysis model of assessment that requires the intricate interpretation of individualised differences in relation to patterns of psychometric test findings. 4,10 assessment in south africa is complicated by the multi-cultural nature of the clientele, and localised research is needed to confirm normative data for use of particular psychometric instruments in this context. 7 cross-cultural effects need to be considered in conjunction with a multitude of other possible contributing factors to variations in cognitive test performance in the cerebrally compromised individual. 9 in our clinical experience in the concussion evaluation area, there are subtleties involved in making sense out of psychometric test scores arising out of serial testing, which make the neurodiagnostic process challenging even for the psychologist with extensive training in psychometrics and expertise in brain-behaviour relations. in accordance with this more circumscribed professional outlook, the necessary role of the psychologist in terms of psychometric test usage is advocated in position statements in both the usa 3 and in south africa. 5 specifically, the health professions council for south africa (hpcsa) has presented its position on the issue as follows: ‘the professional board for psychology is greatly concerned about the growing inappropriate use of psychometric tests…… psychological tests have to be administered, scored, interpreted and reported on by registered persons, who have recognised and appropriate education and training in the field of psychometry’. 5 an exception is not made in respect of computerised psychometric tests, and these require administration and interpretation at the very least under the supervised instruction of the registered psychologist. psychologists with a training in psychometry are the only qualified professionals in a position to evaluate the relative validity of such tests. accordingly, all psychometric tests (including computerised neurocognitive tests) require approval on the basis of an expert review, and formal registration with the hpcsa for their legitimate use in this country. 5 nevertheless, it appears that in a number of instances including the usa and south africa, the computerised neuropsychological evaluation is being conducted by sports medicine clinicians without the involvement of psychologists. where there is a real problem of limited access to specialist services and/or internet facilities, this kind of practice might be professionally defensible. however, we believe that for the most part where this approach is currently being advocated this is probably not the case. the position is made even less acceptable, in terms of what is condoned by the hpcsa, when there is the use of unregistered tests. 5 a concern we have is that these kinds of arguments being advanced by kohler et al. in their letter, are being used spuriously to defend a position which allows medical doctors to perform skills which they are not trained in and which are the province of the specialist traning of psychologists. in the final analysis it is our contention that the need for the neuropsychologist’s contribution in the process needs to be acknowledged and made use of, especially for the interpretation of test data. 3,6 as indicated above, accessibility to specialist involvement of this type is greatly facilitated through internet facilities and can usefully be encouraged. 1 furthermore, with specific reference to the south african context, we would like to highlight the professional dilemma pg100-104.indd 102 10/3/07 3:30:22 pm 102 sajsm vol 19 no.3 2007 pg100-104.indd 103 10/3/07 3:30:22 pm 104 sajsm vol 19 no.3 2007 of failing to comply with the injunctions of the hpcsa (as cited above) 5 in respect of the appropriate approval and implementation of psychometric tests that is considered to be the specialist realm of the registered psychologist. within the current understanding of best practice in the health professions, there is an obligation on practitioners to provide services that stand up to scientific examination in terms of the current literature. especially it is expected that practitioners should operate strictly within the scope of their experience and training. under medicolegal scrutiny, the argument of scarcity of appropriate resources (especially when this is not strictly the case) may not be accepted as a basis for justifying less than optimal parameters for professional practice. ann edwards vicky whitefield national sports concussion initiative (nsci), psychology department, rhodes university, grahamstown notes: in south africa there is no specialist registration for clinical neuropsychology and hence the term ‘neuropsychologist’ in the south african professional setting refers to a registered psychologist who has developed a special interest area and expertise in neuropsychology. the authors are commercially involved in the development of neurocognitive screening as a component of sports concussion management in south africa and britain, using the impact programme in collaboration with the university of pittsburgh medical centre sports concussion programme, usa. the impact programme, available in english and afrikaans, is registered with the hpcsa as an approved test for use by licensed psychologists in this country. 1. collie a, darby d, maruff p. computerised cognitive assessment of athletes with sports related head injury. brit j sports med 2001; 35: 297-302. 2. collie a, maruff p. computerised neuropsychological testing. br j sports med 2003; 37: 2-3. 3. guskiewicz km, bruce de, cantu rc, et al. national athletic trainers’ association position statement: management of sport-related concussion. journal of athletic training 2004; 39: 297. 4. lezak md, howieson db, loring dw. neuropsychological assessment. 4th ed. oxford: oxford university press, 2004. 5. makgoke p. media statement by the health professions council of south africa (hpcsa). south african psychiatry review 2004; 7: 39. 6. shuttleworth-edwards ab, border ma. computer based screening in concussion management: use versus abuse. br j sports med 2002; 36: 473. 7. shuttleworth-edwards ab, kemp r, rust a, muirhead j, hartman n, radloff s. cross-cultural effects on iq test performance: a review and preliminary normative indications on wais-iii test performance. j clin exp neuropsychol 2004; 26: 903-20. 8. shuttleworth-edwards ab, whitefield vj. ethically we can no longer sit on the fence: a neuropsychological perspective on the cerebrally hazardous contact sports. s afr j sports med 2007; 19: 32-8. 9. shuttleworth-jordan ab. age and education effects on brain-damaged subjects: negative findings revisited. clin neuropsychol 1997; 11: 205-9. 10. walsh k. understanding brain damage: a primer of neuropsychological evaluation. 2nd ed. melbourne: churchill livingstone, 1991.        12 th biennial congress of the south african sports medicine association incorporating the 1 st sa rugby medical association diep-in-die-berg, pretoria 14-16 th november 2007 www.sasma.org.za / www.sasma.co.za speakers international and national expert speakers will participate in the meeting. congress committee dr demitri constantinou dr louis holtzhausen prof martin schwellnus dr christa janse van rensburg congress organiser lauren mann tel: 011 717 3372 l cell: 073 886 7970 fax: 0866363166 or 011 717 3379 email: lauren.mann@wits.ac.za congress address sasma c/o centre for exercise science and sports medicine, wits medical school, 7 york road, parktown, 2193, south africa pg100-104.indd 104 10/3/07 3:30:22 pm original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license match loads of university rugby union players between the 2016 and 2018 varsity cup competitions g gordon,1 mphil, h morris-eyton,1 dphil, a kubayi,2 dphil 1 department of sport and movement studies, university of johannesburg, doornfontein campus, south africa 2 department of sport, rehabilitation and dental sciences, faculty of science, tshwane university of technology, pretoria, south africa corresponding author: g gordon (greg4gordon@gmail.com) rugby union has become one of the most exciting and a continuously growing sport around the world.[1] in rugby union, players experience an extensive amount of highintensity running, with bouts of low intensities which occur throughout matches.[2] the game of rugby requires players to be well-conditioned with respect to endurance, speed, agility, power, flexibility and game-specific skills.[3,4] the use of microtechnology, such as global positioning system (gps) devices, has enabled practitioners to quantify the match loads of rugby union players.[5,6] the knowledge gained from this technology allows for detailed position specific movement profiles that could help facilitate optimal player training programmes in match-play preparation. [5,6,7] the characteristics of the in-game demands have been explored generally between the forward and backline players in rugby union.[7] total distance has been reported to be dependent on playing position, with backline players covering greater distance (6471 m) than forwards (5853 m) during matches.[8] in a related study, a detailed analysis of physical demands among professional rugby union players at university level in england was carried out by read et al. [9]. findings showed that forwards and backline players covered total distances of 4683 m and 5889 m, respectively. [9] it was further reported that forwards typically accumulated greater player load and player load (slow) measures than backs. [9] the high volume of these metrics could be due to short burst of directional changes associated with backline players during match-play.[10] differences between positions have also been noted in relation to high-intensity activities during match-play. [10] a systematic review by glassbrook et al. [11] found that backline players covered the greatest relative distance at high speed; however, it was not significantly different to the forwards in the professional rugby league. in contrast, forwards covered significantly less slow-speed distance than the backs. the authors further reported that forwards completed the greatest number of repeated high-intensity efforts (rhie) over a full match than backs.[11] previous studies have found that backline players covered a higher number of sprints and accelerations than forward players.[12,13] despite the physical demands of rugby union players in professional leagues, [7, 11] there is a paucity of information on university players in south africa. with the game of rugby union evolving, it is important for coaches to better understand the physical demands of the modern game to implement more specific training programmes.[4] understanding the physical demands of rugby players during match-play is essential for sports scientists and coaches to develop game-specific conditioning programmes. [11, 14] the aim of this study was to analyse the match loads of rugby union players between the 2016 and 2018 varsity cup competitions. methods research design this study used a longitudinal retrospective quantitative design utilising secondary data. participants the sample consisted of 562 match observations of male university rugby union players from 25 matches in the 2016– 2018 varsity cup tournaments. the players were grouped according to the following playing positions: forwards and backs. ethical clearance was obtained from the university ethics committee (rec-01-159-2018). data collection data were collected by a strength and conditioning coach who used the catapult optimeye x4 microtechnology device which was worn by each player in a tight vest during the matches. the microtechnology device has shown levels of accuracy and reliability for distance and speed measurements during intermittent exercise bouts involving high-intensity actions.[15] background: rugby union is a popular and continuously growing sport globally. with the advance of technology, practices have been implemented to quantify the match running demands of rugby union players. the aim of this study was to analyse the match loads of rugby union players between the 2016 and 2018 varsity cup competitions. methods: the sample consisted of 562 match observations of male university rugby union players competing in the varsity cup tournaments. results: the backline players ran significantly longer total distances (5105 m; p = 0.001; es = 0.49); have greater highspeed running (496 m; p = 0.001; es = 1.03), very high-speed running (260 m; p = 0.001; es = 1.50) and sprint distances (117 m; p = 0.001; es = 1.32) than forward players. backline players also accumulated a high number of metres per minute (238 ± 94; p = 0.001; es = 0.46), total player load (488 ± 203; p = 0.001; es = 0.31), rhie (9 ± 8; p = 0.001; es = 0.75) and number of accelerations (4 ± 5; p = 0.001; es = 0.49). conclusion: these findings may assist coaches to develop player position specific training programmes to meet the physical demands of rugby. keywords: rugby union, match loads, physical demands, position s afr j sports med 2020;32:1-4. doi: 10.17159/2078-516x/2020/v32i1a7949 mailto:greg4gordon@gmail.com http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7949 https://orcid.org/0000-0002-8370-3056 https://orcid.org/0000-0002-2803-6940 original research sajsm vol. 32 no. 1 2020 2 the distances examined are total distances, as well as distances covered in four key velocity bands. these were moderate speed running (7–16 km/h), high-speed running (16–20 km/h), very high-speed running (20–25 km/h) and sprinting distance (>25 km/h). player load expresses arbitrary units of the square root of the sum of the squared instantaneous rates of change in acceleration in each of the three planes of motion and further divided by 100. [15] the difference between player load and player load (slow) is that in the latter, the velocities achieved by the players are less than 2 m.s-1. [9] another metric unit which is widely accepted as a critical variable to consider is rhie. these efforts take place, with minimal recovery (~6 s), during and after tasks such as tackles, rucks, and accelerations during match-play. [14] after every match, the data were exported to a microsoft excel spreadsheet. statistical analysis data were reported as means ± standard deviations. an independent t-test was used to compare differences on match loads between back and forward players. two-way analysis of variance was used to examine the interaction between the year and playing position (backs and forwards) on match running distances of rugby union players. a significance level was set at p<0.05. effect size (es) was also used to assess the magnitude of the differences in the mean scores of variables. es values were interpreted as follows: trivial (<0.20); small (0.20–0.59); moderate (0.60–1.19); large (1.20–2.00); and very large (>2.00).[16] all analyses were conducted using the ibm spss version 25. results table 1 shows the match running loads of rugby players according to playing position. backline players showed significantly higher averages than forward players on the following variables: total distance (5105 ± 2150 m; p = 0.001; es = 0.49, small effect), high-speed running (496 ± 258 m; p = 0.001; es = 1.03, moderate effect), very high-speed running (260 ± 136 m; p = 0.001; es = 1.50, large effect), sprinting distance (117 ± 99 m; p = 0.001; es = 1.32, large effect), metre per minute (238 ± 94; p = 0.00; es = 0.46, small effect), total player load (488 ± 203; p = 0.001; es = 0.31, small effect), rhie (9 ± 8; p = 0.001; es = 0.75, moderate effect) and number of accelerations (4 ± 5; p = 0.001; es = 0.49, small effect). in contrast, forwards had higher player load (slow) (186 ± 86; p = 0.52; es = 0.06, trivial effect) than backline players. table 2 shows the match running demands of rugby union players from 2016 to 2018 varsity cup tournaments. in 2016, forwards ran the highest total distance (4370 ± 2062 m), with the players running less in 2017 (4145 ± 1902 m; es = 0.11, trivial effect) and 2018 (3821 ± 1937 m; es = 0.27, small effect). the backs ran larger total distances in 2017 (5284 ± 1856 m) compared to 2016 (5092 ± 2293 m; es = 0.09, trivial effect) and 2018 (4952 ± 2275 m; es = 0.16, trivial effect). in 2017, the forwards covered more distance in high-speed running (268 ± 176 m) and very high-speed running (87 ± 92 m) than in 2018 (237 ± 185 m; 70 ± 83 m), although trivial effects were observed. discussion the aim of this study was to analyse the match loads of rugby union players between the 2016 and 2018 varsity cup competitions. the findings showed that backline players covered total distances of 5105 m while forwards ran 4097 m table 2. match running demands of rugby players according to year and playing position 2016 2017 2018 variable forwards backs forwards backs forwards backs total distance (m) 4370 ± 2062 5092 ± 2293 4145 ± 1902 5284 ± 1856 3821 ± 1937 4952 ± 2275 moderate-speed running (m) 1776 ± 872 1737 ± 855 1911 ± 890 2026 ± 752 1774 ± 871 1845 ± 854 high-speed running (m) 285 ± 205 498 ± 274 268 ± 176 502 ± 236 237 ± 185 489 ± 265 very high-speed running (m) 102 ± 102 257 ± 144 87 ± 92 258 ± 114 70 ± 83 264 ± 147 sprinting distance (m) 18 ± 31 110 ± 94 22 ± 42 112 ± 78 16 ± 27 127 ± 119 metres per minute 211 ± 94 244 ± 105 197 ± 83 246 ± 82 185 ± 78 226 ± 93 total player load 419 ± 189 467 ± 211 445 ± 204 513 ± 175 414 ± 209 485 ± 219 player load (slow) 195 ± 82 178 ± 78 186 ± 87 187 ± 63 178 ± 89 179 ± 82 rhie 1 ± 2 3 ± 3 2 ± 4 6 ± 6 7 ± 7 16 ± 9 number of accelerations (n) 1 ± 1 1 ± 1 1 ± 3 3 ± 4 5 ± 4 8 ± 5 data expressed as mean ± sd. total player load, player load (slow) and rhie expressed as arbitrary units. rhie, repeated high intensity effort. table 1. overall match running demands of rugby players according to playing position variable forwards mean ± sd backs mean ± sd p-value effect size total distance (m) 4097 ± 1971 5105 ± 2150 0.00* 0.49 (small) moderate speed running (m) 1821 ± 877 1868 ± 828 0.52 0.06 (trivial) high-speed running (m) 262 ± 189 496 ± 258 0.00* 1.03 (moderate) very high-speed running (m) 85 ± 93 260 ± 136 0.00* 1.50 (large) sprinting distance (m) 19 ± 34 117 ± 99 0.00* 1.32 (large) meter per minute (m) 197 ± 85 238 ± 94 0.00* 0.46 (small) total player load 426 ± 201 488 ± 203 0.00* 0.31 (small) player load (slow) 186 ± 86 181 ± 75 0.52 0.06 (trivial) rhie 4 ± 5 9 ± 8 0.00* 0.75 (moderate) number of accelerations (n) 2 ± 3 4 ± 5 0.00* 0.49 (small) *indicates significant at p<0.05. total player load, player load (slow) and rhie expressed as arbitrary units. rhie, repeated high intensity effort. original research 3 sajsm vol. 32 no. 1 2020 during rugby matches. the reason why forwards covered less distance is because of the game dynamics as they are more involved in set pieces and collisions. however, the present results are lower than those of yamamoto et al. [17] who reported that backline players and forwards covered total distances of 6392 m and 5731 m, respectively. the low total distances observed in the current study may be attributed to the fact that the sample consisted of semi-professional rugby union players from the university competition, while that of yamamoto et al. [17] included professional players from the japanese domestic league teams. this supports gabbett et al.,[14] who highlighted that the professional rugby league places considerable physical demands on the aerobic energy system. therefore, the level of competitiveness may differ within teams of elite and less elite players, as well as teams playing in different countries.[3-8, 14] the greater physical demands on backline players in the present study demonstrates that conditioning drills can then be tailored to the specific playing position match demands. [11] backline players covered longer distances at very highspeed levels and with sprinting than forwards, by a large proportion. these findings are in line with those of austin et al. [5] and lacome et al. [13] respectively who reported that forwards run significantly lower total distances during a match. a plausible reason for this finding could be that backline players cover larger distances in matches because they generally run from a deeper position in field than their forward counterparts, thus creating more space for the backline players to gain speed for their runs with the ball in hand. [13] consistent with previous research, [11] the present study suggests that forwards should be prescribed more low intensity activities than backline players but should complete prescribed high speed and sprinting distances. this study also found that backline players had a significantly higher total player load than forwards. a possible explanation for this may be that backs are attributable to both being tackled and having short bursts of changes of direction during matches.[10] it should be noted, however, that the magnitude of the difference in total player load was small between backline players and forwards, demonstrating that there are minor variations in the physical demands of rugby matches at university level. the current study also indicated that forwards had greater player load (slow) than backline players. therefore, it seems that both backline players and forwards accumulate similar loads from low velocity activities such as tackles and physical collisions. [10] this result contrasts with previous research which found that backline players achieved a higher player load (slow) than forwards in new zealand. [10] such discrepancies could be due to different playing tactics or strategies and the physical capacities of players across countries. backline players recorded a significantly higher number of accelerations than the forwards. yamamoto et al. [17] indicated that backline players are more likely to perform intense accelerations than their forward counterparts during the game. it has been previously reported by mclellan,[18] that backline players are found in more space on the outer edges of the field. as a result, they need to accelerate to reach the opposition when carrying the ball, as well as having to sprint when performing kicks and chases.[18] in view of the importance of acceleration in rugby union, the training programmes should consider the differences in the playing positions. sprint training programmes for rugby players should focus on developing acceleration qualities for all playing positions, with the greater emphasis on backline players. preferably, forwards should emphasise acceleration from a standing start, while backline players are needed to effectively change between jogging and sprinting.[19] in the 2016 varsity cup, forwards ran their highest total distance, while running less in the 2017 and 2018 varsity cups respectively. when the point of origin law was introduced in 2016, the teams may have been uncertain how to fully utilise this law to their advantage and therefore this may be a reason as to why the forwards ran their highest distance during matches in 2016.[20] a variation in this law occurred in 2017, which may have influenced the team to change their in-game tactics to use this variation to their benefit. this law was aimed at promoting attacking rugby and ball retention, and therefore players may have had increased possession and opportunities to run further during matches.[20] limitations and future research although this study provided novel information on match running demands of university rugby union players, certain limitations should be noted. the current study consisted of players from one team, which limits the generalisation of findings to the whole population. furthermore, this study did not consider a specific playing position (i.e. front row forwards, back row forwards, inside backs and outside backs), locomotive characteristics (accelerations and decelerations) and situational variables (quality of opponents and match outcome). future studies should also combine gps to match physical demands and technical indicators using video-based performance to provide a comprehensive reflection of the more specific running position profiles of university rugby players. conclusion this study found that backline players significantly covered greater total distances, high-speed running, very high-speed running and sprinting distance than forwards. the backline players also had higher averages on rhie, total player load and number of accelerations than forwards. these results have practical implications for rugby coaches in the development and implementation of individualised training sessions according to playing position. therefore, it is recommended that training for backline players should focus on developing aerobic capacity and sprint training sessions in a match scenario. similarly, low speed running exercises should be recommended for forwards while completing the prescribed high-speed and sprinting distances. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: g gordon collected the data and drafted the manuscript. original research sajsm vol. 32 no. 1 2020 4 h morris-eyton and a kubayi planned the study and contributed to the writing of this manuscript. references 1. world rugby. world rugby year in review 2017. available at: http://publications.worldrugby.org/yearinreview2017/en/1-1 [accessed 10 jul. 2018]. 2. green a, kerr s, olivier b, et al. a simulated rugby match protocol induces physiological fatigue without decreased individual scrummaging performance. s afr j sports med 2017; 29(1):1-6. 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[doi: 10.1519/r-16784.1] [pmid: 16506864] 20. fnb varsity cup. varsity cup south africa, 2018. https://www.varsitycup.co.za/ https://doi.org/10.17159/2078-516x/2017/v29i1a3084 https://doi.org/10.1016/j.jsams.2011.01.003 https://doi.org/10.1016/j.jsams.2011.01.003 https://doi.org/10.1007/s40279-013-0069-2 https://doi.org/10.1080/02640414.2012.727456 https://doi.org/10.3233/ies-2012-0444 https://doi.org/10.1519/jsc.0000000000001600 https://doi.org/10.1519/jsc.0000000000001600 https://doi.org/10.1519/jsc.0000000000002605 https://doi.org/10.1186/s40798-019-0197-9 https://doi.org/10.1519/jsc.0b013e3181a3928b https://doi.org/10.1519/jsc.0b013e3181a3928b https://doi.org/10.1080/02640414.2013.823225 https://doi.org/10.1080/02640414.2013.823225 https://doi.org/10.1016/j.jsams.2011.07.004 https://doi.org/10.1016/j.jsams.2011.07.004 https://hydra.hull.ac.uk/resources/hull:15152 https://doi.org/10.1123/ijspp.1.1.50 https://doi.org/10.1136/bmjsem-2019-000659 https://doi.org/10.4172/2324-9080.1000126 https://doi.org/10.1519/00124278-200602000-00034 sajsm 595 (commentarty).indd commentary 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license ketone body supplement label claims: what supplement has been supplemented? d da costa, hons sports science (biokinetics)1, v bangalee, phd (health science)1, k subban, mbchb2, r naidoo, phd (sports science)1 1 discipline of biokinetics, exercise and leisure sciences, university of kwazulu-natal, college of health sciences, south africa 2 prime human performance institute, 44 isaiah ntshangase road, durban, south africa corresponding author: r naidoo (naidoor3@ukzn.ac.za) participants in recreational and competitive sports are constantly seeking ways to improve their performance. the widespread use of dietary supplements and their associated benefits in sporting performance has always been a topic of interest. many of these products contain ingredients in varied mixtures and quantities. it is well documented that nutrient manipulation[1-3] can increase aerobic exercise performance. traditionally, supplementation focussed on glucose as a fuel source for increasing performance. more recently, awareness has shifted to the role of ketone body supplements to increase performance. ketone bodies can be endogenous where they are produced by the body in the liver, or exogenous, where they are taken in the form of a supplement [4]. ketone body supplements are commonly composed of β-hydroxybutyrate (βhb) combined with a salt, such as potassium, calcium or sodium (naβhb)[4], which are then known as ketone salts. a ketone ester, otherwise known as a ketone monoester, such as (r)-3-hydroxybutyl (r)-3hydroxybutyrate, is salt-free[5] and not commercially available. ketone bodies, namely acetoacetate (acac), acetone, and βhb are lipid-based organic compounds produced by the liver during times of starvation and nutritional manipulation[3], such as a highfat, low-carb (hflc) diet, also known as a ketogenic diet[6]. increasing blood ketone body levels, with accompanying decreases in blood glucose may indicate a state of nutritional ketosis, whereby the body no longer relies on glucose metabolism but rather the metabolism of ketone bodies[2]. following a ketogenic diet is not always easy, hence convenient alternative methods were introduced, such as the consumption of drinks containing exogenous ketone supplements. modern ketone supplement manufacturers claim to cut out this nutritional manipulation period with the ingestion of a supplement containing on average 12g βhb[4]. this amount can be supported by studies[1-3] showing that by ingesting a ketone supplement, can result in ketosis in 30 minutes. theoretically, increasing ketone body production via the decreased availability of glucose in the body, the ketone bodies become the alternative fuel source necessary for the brain and muscles of the body[4]. thus, it is suggested that ketone supplementation has potential positive effects on exercise metabolism and performance in recreational and competitive sportspeople. however, these claims are based on limited studies[1]. a study conducted by clarke et al.[7] found that the ingestion of ketone esters taken in a fasted state showed modest power output improvements in 30 minutes of rowing (averaging ~1% and up to ~2%) in 22 sub-elite male and female athletes. a similar study conducted by cox et al.[8] on 39 endurance athletes showed that the ingestion of ketone esters resulted in decreased lactate production with an average lactate concentration value of ~2-3 mmol (~50%) lower compared to a carbohydrate supplement. this decrease in lactate production could result in an increase in the performance of cyclists[8]. although both studies showed positive reactions to the esters, they are very expensive and not commercially available. furthermore, both studies had small sample sizes. it has been suggested that ketone body metabolism may reduce the use of blood glucose and muscle glycogen, which could be beneficial for long, slow steady-state endurance exercise. although glycogen sparing may be beneficial for endurance in long duration events, such as cycling, there are periods of high intensity where glucose is needed as the primary substrate. this suggests that ketone body supplementation may in fact lower the capacity to sustain high intensity efforts during endurance races. two studies conducted on cyclists have shown that both ketone salts[9] and ketone esters[10] result in a decrease in power output and cadence. furthermore, rodger[3] showed that the ingestion of a ketone body supplement by 12 highly-trained cyclists increased the respiratory exchange ratio (rer) and vo2 values at submaximal levels but failed to increase power output in four minutes of cycling[3]. in addition, short[11] found an increase in cycling performance in 12 recreational athletes following the ingestion of a ketone body supplement containing both βhb and caffeine (caffeine being a known performance enhancer). thus it background: there is a keen interest in performance-enhancing supplementation and the associated benefits, despite reports of incorrect label claims made by manufacturers and the questionable efficacy of the supplements. the use of ketone body supplements as a source of fuel during exercise and sporting performance, in particular, is of interest to sportspeople. by increasing blood ketone body levels, with an accompanying decrease in blood glucose, may indicate a state of nutritional ketosis, whereby the body no longer relies on glucose metabolism but rather the metabolism of ketone bodies. this could be beneficial for long, slow steady-state endurance exercise. discussion: there are numerous ketone body supplements on the market manufactured in south africa and internationally. however, unlike medicines, the sports supplementation industry is poorly regulated. furthermore, ketone body supplementation with regard to its effects on improving exercise and athletic performance is still unconvincing. conclusion: within the ever-changing sports supplementation industry, ketone body supplements are being used despite controversies regarding the accuracy and scientific merit of label claims. the ingredients and their quantities, as well as the performance benefits, need to be objectively validated. keywords: athletic performance, nutritional ketosis, βhydroxybutyrate (βhb) s afr j sports med 2019; 31:1-2.doi: 10.17159/2078-516x/2019/v31i1a6369 mailto:naidoor3@ukzn.ac.za http://dx.doi.org/10.17159/2078-516x/2019/v31i1a6369 https://orcid.org/0000-0002-9664-3734 https://orcid.org/0000-0002-9613-1501 commentary sajsm vol. 31 no. 1 2019 2 could be argued whether it was either the caffeine or the βhb that induced an effect on performance. discussion it is evident that the label claims of ketone body supplements on their effects with regard to exercise and sports performance are unconvincing and unsuccessful when tested in real-life situations[3, 11, 9]. studies on ketone body metabolism during exercise are limited and there is no conclusive evidence supporting this for exercise and athletic performance enhancement[6]. furthermore, particular attention needs to be paid to the ingredients in these supplements and their respective quantities. unlike medication, supplementation is poorly regulated internationally, as premarket approval by bodies such as the food and drug administration (fda) and the south african health products regulatory authority (sahrpa), with a few exceptions, unnecessary. thus the regulation of performance-enhancing supplementation is often entrusted to their distributors and manufacturers to ensure that these products are both safe and effective. sahpra monitors certain but not all performance-enhancing supplements in south africa, leaving the majority of both local and international supplements unregulated [12]. studies conducted on ketone body metabolism have repeatedly stated the adverse effects of ingesting ketone body salts and or esters[4, 6, 10]. some of these effects include gastrointestinal tract discomfort, nausea, diarrhoea and abdominal pain, which may counteract any additional benefits associated with higher doses of these products [3]. a study by veech[5] found that only ketone esters should be used, as increased ketone salts could result in acidosis. another study[4] found that if following the recommended daily serving sizes, the recommended daily allowances of minerals found in most supplements were up to five times higher than necessary, potentially causing metabolic alkalosis, a condition in which the ph of tissue is elevated beyond the normal range [4]. apart from the documented adverse effects, atten tion also needs to be given to the costs of ketone body supplements. pure βhb salts cost approximately $235 (r3370) for 50g. this converts to approximately $67 (r960) per 12g of βhb salts, yet wholesale ketone body supplements containing up to 12g of βhb salts per sachet are being sold for as little as $2.80 (r40) [4]. the mixture of ingredients and related quantities of each ingredient needs to be queried. conclusion as recreational and competitive sportspersons are continually seeking new ways to increase their performance, it is apparent that dietary supplementation is a popular method of choice [1]. despite the negative side effects and the limited evidence based research on exercise and athletic performance, together with inaccurate supplement label claims, ketone body supplements continue to be used among sportspeople. the accuracy and scientific merit of the product label claims are controversial. the ingredients and their quantities, as well as their performance benefits, need to be objectively validated. furthermore, if the composition of the supplement is questionable, then the validity of the research on selected dietary supplements is compromised. funding: research reported in this commentary was supported by the fogarty international center (fic), nationa l institutes of health (nih) common fund, office of strategic coordination, office of the director (cf/osc/od/nih), office of aids research, office of the director (oar/od/nih), national institute of mental health (nimh/nih), award number d43tw010131. the content is solely the responsibility of the authors and does not necessarily represent the official views of the nih. conflicts of interest: the authors declare no conflicts of interest with respect to the authorship and/or publication of this article. author contributions: d da costa was the principal researcher and responsible for the data collection, conceptualisation and drafting of the paper. r naidoo and v bangalee were the project supervisors and provided conceptual input into the research methodology and critical input throughout the writing process. k subban was a collaborator on the research project and provided conceptual input into the research methodology. references 1. cox pj, clarke k. acute nutritional ketosis: implications for exercise performance and metabolism. extrem physiol med 2014;3:17. [doi:. 10.1186/2046-7648-3-17] 2. holdsworth da, cox pj, et al. a ketone ester drink increases postexercise muscle glycogen synthesis in humans. med sci sports exerc 2017:17891795. [doi: 10.1249/mss.0000000000001292] 3. rodger s, plews d, et al. the effects of an oral þ-hydroxybutyrate supplement on exercise metabolism and cycling performance. j sci cycling 2017; 6(1):26-31.[doi: 10.28985/171231.jsc.05] 4. fischer t, och u, et al. effect of a sodium and calcium dl-βhydroxybutyrate salt in healthy adults. j nutr metab 2018;2018:9812806. [doi: 10.1155/2018/9812806] 5. veech rl. ketone ester effects on metabolism and transcription. j lipid res 2014;55(10):2004-2006. [doi: 10.1194/jlr.r046292] 6. pinckaers pj, churchward-venne ta, et al. sports med 2017; 47: 383-391. [doi: 10.1007/s40279-016-0577-y] 7. clarke k, cox p. ketone bodies and ketone body esters for maintaining or improving muscle power output. unpublished observations, 2015. 8. cox p, kirk t, et al. nutritional ketosis alters fuel preference and thereby endurance performance in athletes. cell metab 2016;24(2):256 – 268. [doi: 10.1016/j.cmet.2016.07.010] 9. o’malley t, myette-cote e, et al. nutritional ketone salts increases fat oxidation but impair high-intensity exercise performance in healthy adult males. appl physiol nutr metab 2017. 42(10):1031-1035. [doi: 10.1139/apnm-2016-0641] 10. lecky jj, ross ml, et al. ketone diester ingestion impairs timetrial performance in professional cyclists. front physiol 2017;8:806. [doi: 10.3389/fphys.2017.00806] 11. short j. effects of a ketone/caffeine supplement on cycling and cognitive performance. unpublished thesis, ohio state university, 2017. 12. wallace tc. twenty years of the dietary supplement health and education act – how should dietary supplements be regulated? j nutr. 2015;1 45:1683-1686. [doi: 10.3945/jn.115.211102] original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license does a greater training load increase the risk of injury and illness in ultramarathon runners? : a prospective, descriptive, longitudinal design n craddock,1 bsc (physiotherapy); k buchholtz,2,3 mphil (sports physiotherapy); t l burgess,1,4 phd (exercise science), mhsc (bioethics), bsc (physiotherapy) 1 division of physiotherapy, department of health and rehabilitation sciences, university of cape town, old main building, groo te schuur hospital, anzio road, observatory, cape town, south africa 2 division of exercise science and sports medicine, faculty of health sciences, university of cape town 3 department of physiotherapy, lunex university, luxembourg 4 centre for medical ethics and law, faculty of medicine and health sciences, stellenbosch university, cape town, south africa corresponding author: n craddock (nixcraddock07@gmail.com) endurance running has become increasingly popular over the past three decades due to its numerous health benefits and relative accessibility [1]. in particular, there has been a significant rise in participation in ultramarathon running events. despite the positive benefits of running, endurance running has been associated with an increased risk of developing musculoskeletal injury [2]. this is evidenced by an overall running-related injury incidence rate ranging from between 18% and 92% in ultramarathon runners [3]. in addition to this association with injury, ultramarathon running seems to also influence illness risk. while consistent, moderate-intensity exercise has beneficial effects on general health and immune system function, prolonged highintensity exercise has been shown to impair immune system function and thus increase the risk of acquiring an upper respiratory tract infection [4]. the training load of endurance runners could potentially have a profound effect on the development of both runningrelated injury and illness [5]. training is performed in order to bring about positive physiological adaptations in preparation for an athlete’s sporting endeavour, with the aim of maximising performance. however, it is hypothesised that too great a training load could predispose an athlete to injury and illness. in contrast, too small a training load could possibly lead to inadequate conditioning for the requirements of the sport, and thus result in injury and reduced performance [5]. therefore, finding the optimal training load to maximise performance, whilst minimising injury and illness risk, should be the goal of both coaches and athletes. training load as defined by gabbett is the combination of both the absolute load (internal and external training load) and the relative load (week to month ratio) [5]. the internal load of a training session can be calculated as duration multiplied by rating of perceived exertion (rpe) whilst the external training load refers to distance, duration, intensity and frequency [6]. the acute:chronic workload ratio (acwr) describes the acute load in relation to the chronic load. ‘acute’ is one week in duration and ‘chronic’ can be three to six weeks in duration [5]. acute loading is comparable to a state of fatigue and chronic loading is comparable to a state of fitness. therefore, the ratio tells us how ‘prepared’ the athlete is and the relative risk of injury in the following week. the acwr has been utilised as an outcome measure to monitor an athlete’s training load over time [7]. moderate acwrs combined with a high chronic workload overall have been found to decrease the risk of injury [7]. thus, background: ultramarathon running has become extremely popular over the years. despite the numerous health benefits of running, there are also many negative effects of running, such as increased risk of musculoskeletal injury and illness. monitoring of an athlete’s training load has become extremely important in terms of injury prevention. currently, the relationship between training loads and injury and illness incidence is uncertain. objectives: to determine if there are any associations between injury and illness incidences and training loads among ultramarathon runners in the 12 week period preceding an ultramarathon event and the four week period after the event. methods: this prospective, descriptive, longitudinal study design was conducted in 119 runners who were training for the 2019 two oceans ultramarathon event. data were collected once a week via an online logbook over 16 weeks. training parameters measured included weekly average running distance, average duration, average frequency and average sessional rpe. injury data included injury counts, the structure injured, the main anatomical location and the time-loss as a result of injury. illness data included illness counts, the main illness-related symptoms and the time-loss as a result of illness. results: the overall injury incidence was five per 1000 training hours and the overall illness incidence was 16 per 1000 training days. there was a significant relationship between external training load and injury and illness incidence for those who ran less than 30 km per week. there was also a significant relationship between the acwr (acute chronic workload ratio) and injury incidence when the acwr was >1.5 and for illness incidence when the acwr was <0.5. conclusion: the use of both absolute and relative workloads in the monitoring of an athlete’s training load with the aim of minimising injury and illness risk and maximising performance in ultramarathon runners is recommended. keywords: running-related injuries and illness, acute:chronic workload ratio, exponentially-weighted moving average. s afr j sports med 2020;32:1-6. doi: 10.17159/2078-516x/2020/v32i1a8559 mailto:nixcraddock07@gmail.com http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8559 https://orcid.org/0000-0001-9796-2182 https://orcid.org/0000-0002-1976-345x https://orcid.org/0000-0002-6400-3249 original research sajsm vol. 32 no. 1 2020 2 a higher chronic workload increases the athlete’s injury threshold and therefore serves as a protective factor against injury [5]. an acwr of between 0.8 and 1.3 has been proposed to reduce injury risk in team sport athletes such as rugby, soccer and cricket. if an athlete’s acwr is outside of this proposed ‘sweet spot’, the risk of injury and illness is thought to increase [5]. however, this relationship has not been adequately established in ultramarathon runners. recently, the acwr has been criticised for its mathematical flaws [8]. instead, the use of the exponentially weighted moving averages (ewma) in the calculation of the acwr has been proposed as it appears to be more sensitive in determining spikes in training loads [9]. understanding the relationship between training loads, injury and illness profiles of ultramarathon runners may prove to be beneficial in terms of minimising the risk of injury and illness and maximising performance in these athletes [10]. the authors therefore aim to add to current literature with regard to injury and illness profiles of ultramarathon runners, as well as the use of internal training loads, external training loads and the ewma of the acwr in the monitoring and prevention of injury and illness in endurance runners. methods ethical considerations ethical approval was obtained from the university of cape town, faculty of health sciences human research ethics committee prior to the start of the study. participants this prospective, descriptive, longitudinal study design included 119 ultramarathon runners who qualified for the 2019 two oceans ultramarathon race. those with relevant medical or surgical history that would prevent safe participation were excluded from this study. those who did not complete the informed consent form and those who sustained a running-related injury in the seven day period prior to the start of the study were also excluded. measurement instrumentation physical activity readiness questionnaire the physical activity readiness questionnaire (par-q+) was used to screen participants for any potential underlying medical and surgical conditions that may limit safe participation in physical activity. participants who answered ‘no’ to all initial questions were cleared to take part in the study. participants who answered ‘yes’ to one or more of the initial questions then had to complete the follow-up questions. if they further answered ‘yes’ to one or more of the follow-up questions, participants were excluded from the study and advised to seek medical help [11]. baseline questionnaire a self-developed questionnaire was used to establish participants’ training, injury and illness history. the questionnaire was reviewed by a panel of experts to establish content and construct validity. once the validation process was completed, the feasibility of the questionnaire was assessed through a pilot study of four participants. data from pilot study participants were not included for analysis, as they completed the baseline questionnaire only. training injury and illness logbook participants kept a weekly logbook of their training, injury and health information for the 16-week study period, which comprised 12 weeks before the race and four weeks after the race. training information included average training distance (km.week-1), duration (min.week-1), and frequency (sessions.week-1). participants also recorded average weekly rate of perceived exertion (rpe), using the modified borg scale [12]. participants indicated if they had sustained a runningrelated injury each week. participants who sustained injuries recorded if the injury was new or recurrent, the injury type, as well as the site of pain. time-loss from running was also recorded. participants documented their weekly health status and if they had contracted any new or recurring illnesses. participants who reported an illness were requested to document the associated symptoms, the influence of the illness on their participation in training and any treatment that was received for the illness. the logbook was distributed via email on sunday of each week for 16 weeks which contained a link to surveymonkey for completion. data analysis injury incidence was determined according to the authors’ definition of a running-related injury which was taken from the 2015 consensus statement (a modified delphi approach) [13]. a running-related injury was therefore constituted as; ’runningrelated (training or competition) musculoskeletal pain in the lower limbs that causes a restriction on or stoppage of running (distance, speed, duration, or training) for at least seven days or three consecutive scheduled training sessions, or that requires the runner to consult a physician or other health professional ‘[13]. a new injury was defined as any new area of pain and/or the recurrence of a previous injury with more than a week’s gap in symptoms. a recurring injury was defined as the same injury that the participant had experienced in the previous week. injury proportion was calculated as the number of injured participants divided by the total sample size. injury incidence was calculated as the number of injuries per 1000 hours of training. illness incidence was determined as ’a new or recurring illness incurred during competition or training receiving medical attention, regardless of the consequence with respect to absence from competition or training’ [14]. a new illness was defined as illness-related symptoms that the participant had not experienced in the previous week, whereas a recurring illness pertained to illness-related symptoms that the participant had experienced in the previous week. illness proportion was calculated by dividing the number of ill participants by the total sample size. illness incidence was calculated as the number of ill participants per 1000 training days. original research 3 sajsm vol. 32 no. 1 2020 statistical analysis descriptive characteristics of the study population were described using mean and standard deviation. differences in descriptive data between the groups were assessed using an independent t-test. training parameters during the 16-week study period were described using mean and standard deviation for both the injured and uninjured groups, and the ill and healthy groups. weekly and cumulative absolute and relative training load parameters were described using mean and standard deviation for the two groups. the significant difference in the training parameters between the groups was measured using an independent t-test. pearson’s correlations and odds ratios were used to establish associations between injury, illness, and absolute and relative training load variables. statistical significance was accepted as p < 0.05. results at baseline, there were 75 males and 43 females. after the study was completed, participants were divided into an injured (n=37) and uninjured group (n=82); and an ill (n=79) and a healthy group (n=40), based on individual injury or illness reported during the 16-week study period. the average age of participants was 41± 10 years, the average stature was 174.5 ± 9.4 cm, the average body mass was 71.3 ± 12.6 kg and the average bmi was 23.4 ± 2.3 kg/m2. injury profile the overall injury proportion was 31% and the injury incidence was 5 per 1000 hours of training. the average timeloss from injury was 3 ± 2 missed training sessions. the most commonly injured structure was muscle (37%). the knee was the most common site of pain (19%), followed by the foot (14%), hip (12%) and ankle (12%). illness profile the overall illness proportion was 66% and the illness incidence was 16 per 1000 training days. the average time-loss due to illness was 3 ± 1 training sessions missed. the main illnessrelated symptoms that were reported were congestion (54%) and fatigue (20%). training parameters no significant difference was found between the injured and uninjured group in average cumulative distance and average cumulative duration per week. a significant difference was found between the two groups for average frequency (p=0.0286) and average sessional rpe per week (p=0.0030) (table 1). on average, the uninjured group ran significantly more times per week than the injured group and at a significantly higher intensity. a moderate, significant negative correlation was found between average external training load and injury incidence (r=-0.56; p=0.025). as the external training load decreased the injury incidence increased. no correlation was found between average internal training load and injury incidence. no correlation was found between average external training load and average internal training load and illness incidence. no significant relationships were found for internal training load and injury incidence and internal training load and illness table 1. training parameters (average distance, average duration, average frequency and average session rpe) between the total, uninjured and injured groups over the 16-week study time period total group (n=119) uninjured (n=82) injured (n=37) t-value p-value distance (km.wk-1) 52 ± 38 54 ± 31 44 ± 22 1.74 0.08 duration (min.wk-1) 132 ± 129 126 ± 83 128 ± 88 0.13 0.89 frequency (sessions.week-1) 4 ± 2 4 ± 1 3 ± 1 2.23 0.0286* average session rpe (0-10) 4 ± 2 5 ± 1 4 ± 1 3.07 0.0030** data are expressed as mean ± standard deviation (sd). * indicates p<0.05 significant difference; ** indicates p<0.001 significant difference. rpe, rate of perceived exertion. table 2. odds ratio (95% ci) for risk factors for injury incidence and external training loads external week 1 to 4 (early training) week 5 to 8 (mid training) week 9 to 12 (pre-race) week 13 to 16 (post-race) exposure group (km.wk-1) odds ratio (95% ci) p-value odds ratio (95% ci) p-value odds ratio (95% ci) p-value odds ratio (95% ci) p-value ≥0 <30 1.3 (0.6 2.7) 0.46 9.7 (2.0 46.8) 0.0047** 3.4 (0.9 11.6) 0.05 2.2 (0.2 19.8) 0.49 ≥30 <60 1.0 1.0 1.0 1.0 ≥60 <90 0.6 (0.3 1.4) 0.20 4.5 (0.9 22.6) 0.07 0.8 (0.2 3.2) 0.74 1.5 (0.1 24.7) 0.77 ≥90<120 0.5 (0.1 3.8) 0.48 0.9 (0.0 18.5) 0.93 0.4 (0.0 7.3) 0.52 1.0 (0.0 25.7) 0.99 ≥120 2.2 (0.4 11.1) 0.35 2.9 (0.1 64.3) 0.50 3.3 (0.3 32.5) 0.31 3.8 (0.1 103.5) 0.43 * indicates p<0.05 significant difference; ** indicates p<0.001 significant difference. reference group is ≥30<60 km.wk-1. original research sajsm vol. 32 no. 1 2020 4 incidence for those who ran less than 30 km.wk-1. a significant relationship was found for external training load and injury incidence in weeks five to eight for those who ran less than 30 km.wk-1. (table 2). significant relationships were also found for external training load and illness incidence in weeks five to eight, nine to 12 and 13 to 16 for those who ran less than 30 km.wk-1. (table 3). a significant relationship was found for the acwr and injury incidence in weeks one to four, five to eight and 13 to 16 when the acwr was >1.5 (table 4). a significant relationship was found for the acwr and illness incidence in weeks 13 to 16 when the acwr was <0.05 (table 5). table 3. odds ratio (95% ci) for risk factors for illness incidence and external training loads external week 1 to 4 (early training) week 5 to 8 (mid training) week 9 to 12 (pre-race) week 13 to 16 (post-race) exposure group (km.wk-1) odds ratio (95% ci) p-value odds ratio (95% ci) p-value odds ratio (95% ci) p-value odds ratio (95% ci) p-value ≥0<30 1.6 (0.8 2.9) 0.16 2.3 (1.2 4.6) 0.02* 2.9 (1.3 6.2) 0.01** 5.4 (2.3 12.3) 0.0001** ≥30<60 1.0 1.0 1.0 1.0 ≥60<90 0.5 (0.3 1.2) 0.11 1.0 (0.5 2.1) 0.94 0.8 (0.4 1.9) 0.66 1.1 (0.3 3.5) 0.93 ≥90<120 0.7 (0.2 3.4) 0.69 0.6 (0.22.1) 0.43 0.8 (0.2 3.0) 0.75 1.6 (0.4 6.5) 0.53 ≥120 0.7 (0.1 5.7) 0.73 0.7 (0.1 5.8) 0.74 0.4 (0.0 6.9) 0.52 1.77 (0.2 16.2) 0.61 * indicates p<0.05 significant difference; ** indicates p<0.001 significant difference. reference group is ≥30<60 km.wk-1. table 4. odds ratio (95% ci) for risk factors for injury incidence according to acute:chronic workload ratios (acwrs) external week 1 to 4 (early training) week 5 to 8 (mid training) week 9 to 12 (pre-race) week 13 to 16 (post-race) acwr ratios odds ratio (95% ci) p-value odds ratio (95% ci) p-value odds ratio (95% ci) p-value odds ratio (95% ci) p-value ≥0.0 <0.50 3.1 (0.9 9.8) 0.06 1.0 (0.3 3.9) 0.99 0.4 (0.1 1.8) 0.22 0.7 (0.2 3.2) 0.64 ≥0.5 <1.0 0.9 (0.2 3.5) 0.88 1.4 (0.5 4.3) 0.55 0.4 (0.1 1.5) 0.18 0.9 (0.2 4.2) 0.90 ≥1.0 <1.5 1.0 1.0 1.0 1.0 ≥1.5 <2.0 15.2 (3.9 59.8) 0.0001** 0.9 (0.1 17.2) 0.96 1.9 (0.2 16.2) 0.57 5.7 (1.2 27.5) 0.03* ≥2.0 10.7 (0.4 282.9) 0.16 31.0 (1.8 547.9) 0.02* 6.5 (0.3 171.6) 0.26 34.1 (0.6 1920.1) 0.09 * indicates p<0.05 significant difference; ** indicates p<0.001 significant difference. reference ratio is ≥1.0 < 1.5. table 5. odds ratio (95% ci) for risk factors for illness incidence according to acute:chronic workload ratios (acwrs) external week 1 to 4 (early training) week 5 to 8 (mid training) week 9 to 12 (pre-race) week 13 to 16 (post-race) acwr ratios odds ratio (95% ci) p-value odds ratio (95% ci) p-value odds ratio (95% ci) p-value odds ratio (95% ci) p-value ≥0.0 <0.50 1.5 (0.7 3.4) 0.31 1.8 (0.8 4.1) 0.17 1.3 (0.5 3.7) 0.64 2.1 (1.0 4.3) 0.038* ≥0.5 <1.0 1.1 (0.6 2.0) 0.89 1.0 (0.5 1.9) 0.98 1.6 (0.9 3.1) 0.13 1.6 (0.8 3.2) 0.17 ≥1.0 <1.5 1.0 1.0 1.0 1.0 ≥1.5 <2.0 2.1 (0.6 8.3) 0.27 1.8 (0.5 6.8) 0.39 1.8 (0.4 8.8) 0.47 2.4 (0.8 7.3) 0.13 ≥2.0 6.3 (0.1 324.7) 0.36 1.3 (0.1 27.6) 0.87 8.8 (0.2 455.8) 0.28 7.5 (0.1 388.8) 0.32 * indicates p<0.05 significant difference; ** indicates p<0.001 significant difference. reference ratio is ≥1.0 < 1.5. original research 5 sajsm vol. 32 no. 1 2020 discussion a total of 37 participants among the 119 participants sustained a running-related injury over the 16-week study time period, indicating an incidence proportion of 31%. the overall injury incidence was five per 1000 hours of training. the authors used the 2015 consensus statement which identified runningrelated injuries through a modified delphi approach [12]. a running-related injury was classified according to timeloss (three or more missed training sessions) [12]. according to clarsen and bahr the ‘time-loss’ definition of an injury is both reliable and easy to use amongst coaches and athletes and therefore does not require the expertise of a healthcare professional [15]. however, this definition also has several limitations. many injuries may be missed as athletes often continue to train despite having an injury. often these injuries are not serious enough to warrant stopping training but rather managed through load modification, such as reducing the length or intensity of the exercise session and/or through the use of certain over the counter medications [15]. in this study, the anatomical area most commonly injured was the knee (19%), followed by the foot, hip, ankle and hamstring. results from this study are consistent with many other studies which have reported the lower limb to be the most commonly injured area of the body, more specifically the knee [16]. imbalances in the lower limb may contribute to the development of running-related injuries [17]. the hip serves as a dynamic stabiliser of the lower limb. weakness of the hip stabilisers, such as the hip abductors and hip external rotators, has been found in patients with patellofemoral pain syndrome and iliotibial band friction syndrome [17]. weak hip abductors increase the amount of adduction occurring at the hip which increases the angle of pull on the knee [17]. this is supported by ramskov et al. who found greater hip abductor strength to be associated with less patellofemoral pain [18]. other biomechanical abnormalities that have been associated with an increased risk of knee pain include knee malalignment, excessive pronation and an increased q-angle [18]. a total of 79 participants among the 119 participants sustained an illness over the 16-week study time period, indicating an incidence proportion of 66%. the overall illness incidence in this study was 16 per 1000 training days. findings from this study vary with illness incidences found in other studies which could be due to differences in illness definitions and periods of data collection [14]. the main illness-related symptom reported in this study was congestion (54%). schwellnus et al. found that 50% of illnesses reported by athlete’s effect the respiratory tract [14]. symptoms of an upper respiratory tract infection include a sore throat, congestion and cough [14]. following an acute bout of stress (i.e. an ultramarathon), the immune system is believed to be suppressed [4]. it is during this period of decreased immunity that the risk of sustaining an upper respiratory tract infection increases [4]. a significant negative association was found between external training load and injury (r=-0.56; p=0.025). as the external training load decreased the incidence of injury increased. gabbett found that increasing one’s overall training load improves performance [5]. in individual sports, such as running, an association between higher chronic training loads and improved performance has been established [5]. gabbett and whiteley have suggested that if an athlete is loaded beyond the specific requirements of an event or match (i.e. by increasing their overall chronic load) then their risk of injury can be minimised during these high periods of stress and in turn increase an athlete’s injury threshold [10]. an acwr of 0.8 to 1.3 has been recommended as the ‘sweet spot’ in training load prescription, above and below which the relative risk of injury increases [5]. however, this is not specific to ultramarathon running. a significant relationship was found in these authors’ study when examining the acwr and illness incidence when the acwr was <0.5. these findings indicate that a lower training mileage was associated with an increased risk of illness. however, this was found in weeks 13 to 16 after the ultramarathon event took place. thus, this more likely indicates that participating in an ultramarathon increases the risk of illness post event as opposed to a low training mileage being associated with an increased illness incidence. when the acwr was ≥1.5 in these authors’ study, a significant relationship was found between the acwr and relative injury risk. an acwr of >1.5 is suggestive of a sudden ‘spike’ in an athlete’s training load [5]. it is at this point that the risk of injury in the following week starts to rise. the use of the acwr to monitor these sudden spikes in training load as well as determining the athlete’s overall chronic load on a four weekly basis has proven to be effective [9]. both rolling averages and the exponentially weighted moving average have been used in the calculation of the acwr in literature. the ewma method of calculation gives more weighting to recent training loads towards the end of a four week training block and lesser weighting to older values [9]. it appears to be more sensitive to changes in the chronic load as well as predicting signs of fatigue. it is therefore recommended in the calculation of the acwr [9]. the results from this study add to the current knowledgebase on the use of the acwr in ultramarathon runners specifically. for individual athletes, an acwr of 0.5 to 1.5, using the ewma method of calculation, may be appropriate in terms of minimising the risk of injury and illness in the following week until such time as more research is established. conclusion in conclusion, a lower training load could potentially predispose to running-related injuries or the development of illness. specifically, a weekly mileage of less than 30 km per week may increase the risk of sustaining an injury or illness when training for an ultramarathon event. an acwr greater than 1.5 may increase the risk of injury in the subsequent week of training and an acwr less than 0.5 may increase the risk of illness in the following week. non-gradual changes to a weekly training load, whether increases or decreases, could increase the risk of incurring a running-related injury or illness. maintaining an acwr between 0.5 and 1.5 appears to be original research sajsm vol. 32 no. 1 2020 6 optimal in minimising the risk of sustaining a running-related injury or illness. these authors recommend the use of both absolute (internal and external) and relative workloads (ewma of the acwr) in the monitoring of an athlete’s training load with the aim of minimising injury and illness risk and maximising performance in ultramarathon runners. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. acknowledgements: the authors thank stuart buchanan for his help with the statistics as well as the study participants for their contribution to this study. author contributions: nc; 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[doi: 10.7205/milmed-d-1500143][pmid: 27244060] file:///c:/doi:%2010.1135/bjsm.2006.033548 doi:10.1249/jsr.0b013e3182913c98 doi:%2010.2165/11631170-000000000-00000 doi:%2010.2165/11631170-000000000-00000 doi:%2010.1136/bjsports-2015-095788 doi:%2010.2165/11317780-000000000-00000 doi:%2010.2165/11317780-000000000-00000 doi:%2010.1136/bjsports-2015-094817 doi:%2010.1136/bjsports-2015-094817 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:10.1136/bjsports-2016-096589%5d%5bpmid file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1123/ijspp.2016-0321 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi.org/10.2519/jospt.2015.5741 doi:%2010.1136/bjsports-2016-096583 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/doi.org/10.1136/bjsports-2013-093297 https://doi.org/10.1371/journal.pone.0114937 https://doi.org/10.1371/journal.pone.0114937 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1177/1941738109334272 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1177/1941738109334272 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.7205/milmed-d-15-00143 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.7205/milmed-d-15-00143 114 sajsm vol 19 no. 5 2007 what is lactic acid? complaints of legs feeling tired towards the end of a hard run and sore, stiff muscles the day after a race or hard training session have for many years been blamed on the presence of lactic acid in the muscles. briefly, lactic acid, or lactate, is one of two possible products produced by alternative reactions in the glycolytic pathway. 1 the other product, pyruvate, is produced predominantly in the slow-twitch muscle fibres, whereas the poor blood supply and lower mitochondrial content of the fast-twitch muscle fibres favours lactate production. 1 at physiological ph, lactic acid is present in its de-protonated form, lactate. thus, lactate production, and the assumed concomitant release of a hydrogen ion, has long been accepted as the cause of exercise-induced metabolic acidosis. 1,4 the increase in blood lactate that occurs during intense exercise formed one of the landmark discoveries of early exercise scientists. unfortunately, the limited knowledge and resources of the time lead to this phenomenon being somewhat misinterpreted and the resulting ‘red herrings’ continue to hamper many exercise physiologists decades later. history lactic acid was first discovered in a sample of sour milk by swedish chemist carl wilhelm scheele in 1780. 2 although initially greeted with scepticism, the existence of lactic acid was confirmed by 1810, having been isolated from sources including fresh milk, ox meat and blood. 2 a strong connection between lactic acid production and fermentation reactions was duly observed and lactic acid was commonly used to acidify foods and beverages as a form of preservative. 2 the link between lactic acid and exercise may be largely attributed to the pioneering work of otto meyerhof and archibald v hill, who, in the early 1920s, studied the breakdown of carbohydrates in skeletal muscle. meyerhof was particularly interested in the glycolytic pathway and was the first scientist to detail several of the reactions that occurred. he observed that lactic acid was produced from glycolysis when oxygen was absent and it was this discovery that added anaerobiosis (the absence of oxygen) to the existing link between lactic acid, fermentation and acidosis. 3,4 this association between lactic acid, acidosis and anaerobiosis became relevant to exercise when hill was able to quantify the amount of energy transferred when glucose was converted to lactate. his findings led him to propose that the energy of this reaction was enough to power muscle contraction. 3,4 furthermore, hill speculated that lactate production was initiated (i) when oxygen supply to the muscle was inadequate or (ii) when the energy demands of exercise commentary sporting myths: the real role of lactate during exercise abstract background. lactate or, as it was customarily known, ‘lactic acid’ was one of the first molecules to attract the attention of early exercise scientists, mainly because blood lactate concentration could be measured and was shown to increase with increasing exercise intensity. this connection resulted in lactate being associated with numerous other events associated with high-intensity exercise including muscle cramps, fatigue, acidosis and post-exercise muscle soreness. nobel prize-winning research by av hill and otto meyerhof provided a rational explanation linking lactate to anaerobiosis and acidosis, which resulted in this relationship being widely accepted as fact. it was only following isotopic tracer studies of george brooks and others that the true role of lactate during rest and exercise was revealed. conclusions. lactate is now acknowledged as an important intermediate of carbohydrate metabolism, taken up from the blood by tissues such as skeletal and cardiac muscle as a substrate for oxidation. furthermore, lactate formation consumes a proton, thereby buffering against muscle acidosis. for this reason, lactate production forms an essential aid to endurance performance rather than a hindrance. correspondence: theresa mann mrc/uct research unit for exercise science and sports medicine po box 115 newlands 7725 cape town tel: (021) 650-4569 fax: (021) 686-7530 e-mail: mnnthe005@uct.ac.za t mann (bsc (med)(hon) exercise science mrc/uct research unit for exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town pg114-116.indd 114 1/11/08 12:22:16 pm sajsm vol 19 no. 5 2007 115 exceeded what could be supplied using oxygen-dependent metabolism. either of these conditions would necessitate an increase in anaerobic metabolism. thus there appeared to be both evidence and rational explanation for the relationship between anaerobiosis, lactic acid production and acidosis. the fact that meyerhof and hill went on to share a nobel prize for their findings in 1922 lead to these explanations being accepted as fact for a long period to come. enduring misconceptions the relationship between inadequate oxygen supply to the muscles and excessive lactic acid production was assumed to be irrefutable and, in the same way, an increase in blood lactate was blamed for other events associated with highintensity exercise. these included muscle cramps, fatigue, post-exercise muscle soreness and even the formation of scar tissue. scientists were able to further explain the lactate accumulation supposedly responsible for these adverse events by measuring blood lactate at various exercise intensities. they observed that blood lactate concentration only began to increase at a particular point, later described as the ‘anaerobic threshold’. the anaerobic threshold, also known as the ‘lactate threshold’, referred to an exercise intensity at which blood lactate steadily increased above the stable concentration observed at lower workloads. this was taken to represent the point at which oxygen supply to the muscle could not meet the demand placed on aerobic metabolism, forcing a switch to anaerobic metabolism to sustain muscle contractions. furthermore, it was initially believed that lactate could not be easily removed from the muscle and that some lactate remained behind in the muscle after exercise, resulting in pain and stiffness within a few hours. discovery of lactate shuttles the concept of the ‘anaerobic threshold’, although still popular today among certain coaches and exercise scientists, was disproved less than a decade after its inception by george brooks and his colleagues at the university of california (see review paper 5 ). through the infusion of radio-labelled carbon isotopes, incorporated into special ‘tracer’ lactate molecules, brooks was able to track the transport of lactate within the body and also how it was metabolised. his revolutionary finding was that skeletal muscle is a major site of lactate oxidation as well as of lactate production. 5 special membrane proteins termed monocarboxylate transporters allow lactate to be transferred from its primary site of production in the fast-twitch glycolytic muscle fibres to the slow-twitch oxidative muscle fibres. 5 at this point, lactate can be reconverted to pyruvate and used as a substrate for aerobic respiration. the movement of lactate from its site of production to a site where it could be oxidised was dubbed lactate ‘shuttling’ and it is estimated that 75 80% of lactate produced during exercise is oxidised using this mechanism. 5 lactate can be shuttled between fibres of the same muscle or released into the blood for uptake by tissues, including active and inactive muscle, the liver and the heart. 5 skeletal muscles may continually release lactate into the blood stream without any noticeable change in blood lactate concentration. this is because the lactate is removed from the blood by other tissues, including the heart, muscle and liver, at a similar rate. lactate that is not oxidised directly may be converted to glucose or to glycogen. 5 thus, in contrast to its previous reputation as being a dead-end metabolic waste product with destructive consequences, lactate is in fact a valuable distributor of carbohydrate potential energy within and between muscles. with the evidence that lactate is continuously removed from the blood as well as being added to it, it becomes apparent that blood lactate concentration is not a good indicator of how much lactate is being produced by the muscles. currently there is no convincing evidence that muscles ever become ‘anaerobic’ during exercise. 5 moreover, lactate formation has been shown to occur at rest and throughout exercise but is masked by the fact that an increase in lactate release into the blood usually initiates an increase in lactate removal. 5 it is only at the exercise intensity previously termed the ‘anaerobic threshold’ that lactate release into the blood exceeds the rate at which it can be taken up by other tissues, causing the blood concentration to increase. this mismatch between lactate release and uptake occurs as a result of the increased rate of carbohydrate metabolism required to power high-intensity exercise. is lactate accumulation bad? the long-standing association between lactate and anaerobiosis in the muscles appears largely unfounded; nevertheless, allegations of acidosis and muscle soreness following lactate accumulation in the muscle continue to persist. to dispense with the latter, even before the discovery of the lactate shuttling systems, scientists had determined that blood and muscle lactate concentrations return to resting levels within an hour of the exercise session. it is therefore highly unlikely for lactate to cause the pain and stiffness that develops only 12 24 hours after exercise. 6 interestingly, postexercise massage, which may alleviate muscle discomfort, has no effect on blood lactate concentration. there is some evidence that lactate may even be beneficial for muscle recovery by serving as a substrate for glycogen re-synthesis. 4 post-exercise muscle soreness is now largely accepted to be as a result of mechanical damage to the muscle and the associated inflammation. 5 disproving the link between lactate accumulation and acidosis is a somewhat more complex affair. innumerable investigations have shown an inextricable link between increased lactate concentration and decreased blood and muscle ph 7 – long believed to result from the dissociation of protons associated with lactic acid. only recently was this relationship shown to be a correlation only and not a pg114-116.indd 115 1/11/08 12:22:16 pm 116 sajsm vol 19 no. 5 2007 cause-and-effect. rather, it is proposed that rapid turnover of atp, and not increased lactate production, is ultimately responsible for the accumulation of protons at high exercise intensity. 4 ironically, lactate is believed to resist rather than precipitate a fall in ph as formation of lactate from muscle glycogen actually consumes two protons. 4 so is lactate accumulation bad from a muscle function perspective? the evidence is that lactate accumulation is not indicative of anaerobiosis, nor is it the cause of acidosis or post-exercise muscle soreness. to the contrary, lactate is particularly important for (i) the regeneration of the electron carrier, nad + (ii) as a primary precursor for gluconeogenesis and (iii) as distributor of carbohydrate potential energy. thus it appears that lactate accumulation is not inherently bad, indeed, it may even be argued as something of an advantage. references 1. brooks g, fahey t, baldwin k. glycogenolysis and glycolysis in muscle: the cellular degradation of sugar and carbohydrate to pyruvate and lactate. in: exercise physiology: human bioenergetics and its applications, 4th ed. new york: mcgraw hill, 2005: 59-93. 2. holten c, muller a, rehbinder d. lactic acid: property and chemistry of lactic acid and derivatives. germany: verlag chemie, 1971. 3. hill a, long c, lupton h. muscular exercise, lactic acid and the supply and utilization of oxygen. proc r soc lond b biol sci 1924; 16: 84-137. 4. robergs r, ghiasvand f, parker d. biochemistry of exercise-induced metabolic acidosis. am j physiol regul integr comp physiol 2004; 287: r502-r516. 5. brooks g. intraand extra-cellular lactate shuttles. med sci sports exerc 2000; 32(4): 790-9. 6. macintyre d, reid w, mckensie d. delayed muscle soreness. the inflammatory response to muscle injury and its clinical implications. sports med 1995; 20:24-40. 7. sahlin k, harris r, nylind b, hultman e. lactate content and ph in muscle samples obtained after dynamic exercise. pflugers arch 1976; 367:143-9. pg114-116.indd 116 1/11/08 12:22:22 pm sajsm vol 18 no.1 2006 3 the south african sports medicine association (sasma) is undergoing a renaissance with a realignment of their vision and a drive to boost membership. the necessity of having a strong sports medicine association is probably more important now than ever before. the sad deterioration of the standard of sport in south africa and the attempt by some politicians and administrators to hijack sport to fulfill their own agendas is at a critical level. the contribution of sasma to ensure that the situation does not spiral out of control needs to be clarified. among the many goals of sasma, perhaps one of the most important is to provide a vehicle for continuing education so that the members are able to maintain a high level of service provision to patients, athletes and coaches. this high level of service needs to adhere to the principles of best practice. this is perhaps easier said than done. for starters, what constitutes best practice when dealing with high-performance elite teams? this question was raised and discussed on numerous occasions at the recent sports medicine conference in cape town. while there was general agreement that the term ‘best practice’ described a procedure or method that consistently resulted in the desired response, there was less agreement on how this could be achieved. some delegates put forward the view that best practice was synonymous with the concept of evidence-based practice, which in turn strives to apply information gained from scientific experimentation. most trained scientists would concur with this view, while at the same time expressing concern that the scientific process needs to be interpreted and applied accurately. failing this, the system crumbles. while in a clinical setting the inappropriate use of various medical treatments may have life-threatening consequences, the same does not apply to the application of various modalities for training and recovery in sport. therefore there is less scrutiny of these methods and a general muddling of what is based on the personal experience of a practitioner versus what can be considered best practice as a result of supporting scientific evidence. consider the practice of recovery after training and competition – inadequate recovery is listed as one of the major obstacles in attaining optimal performance. 2 while many researchers have attempted to define the ideal recovery strategy, 1 the research on recovery strategies is limited for the following reasons: (i) often untrained people are exposed to a gruelling exercise protocol and then studied with the expectation that they will respond similarly to elite athletes – we know this is not the case; (ii) the protocols used to induce fatigue are not sufficiently specific to the demands of a sport; and (iii) the markers of recovery used in research (i.e. creatine kinase activity in the blood, pain, performance) are not necessarily valid markers of recovery. furthermore, the types of experiments which have a high believability factor are the randomised double-blind placebocontrolled trials. unfortunately these trials are almost impossible to conduct with elite professional athletes. for these reasons the body of scientific information which can be applied to the management of athletes and players after training and competition is limited. this has led to the support staff placing a greater emphasis on personal preferences and experiences of their colleagues when deciding on best practice principles. under these circumstances there is no alternative. however, there should be extra vigilance when these practices are used. consider for example the use of cold-water immersion of players after training and competition. this practice is based in the theory that inflammation which occurs after hard training and competition is a negative biological consequence and therefore should be prevented – while this logic may be correct when used to treat injured muscle and soft tissue in the acute phase of injury, does it really apply to training-induced stress? a recently published study would suggest not. 3 this study examined the training-induced adaptations in a group of subjects who had their trained limbs exposed to cold-water immersion after every training session – surprisingly, this treatment reduced the training-induced adaptations, leading the authors to conclude that the muscle hyperthermia associated with training, and which is blocked by exposure to cold-water immersion, is an important biological stimulus for inducing training adaptations. this is just an example of how treatments may be misused in the absence of good convincing data. it is unlikely that this will change in the foreseeable future. therefore there is no simple solution other than encouraging practitioners and service providers working with sports participants to have open minds and communicate with colleagues, be alert for dogmatic viewpoints, and be aware of pseudo-science being used to promote extreme viewpoints. sasma can assist in this ongoing education role providing the regions become strong and vibrant. mike lambert editor-in-chief 1. barnett a. using recovery modalities between training sessions in elite athletes: does it help? sports med 2006; 36: 781-96. 2. smith dj. a framework for understanding the training process leading to elite performance. sports med 2003; 33: 1103-26. 3. yamane m, teruya h, nakano m, ogai r, ohnishi n, kosaka m. postexercise leg and forearm flexor muscle cooling in humans attenuates endurance and resistance training effects on muscle performance and on circulatory adaptation. eur j appl physiol 2006; 96: 572-80. best practice in high-performance sport a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm editorial sajsm vol 20 no. 3 2008 63 editorial.indd 63 10/17/08 11:14:15 am original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the effects of a four weeks combined resistance training programme on cricket bowling velocity r maker, mtech; ms taliep, phd department of sport management, cape peninsula university of technology, cape town, south africa corresponding author: ms taliep (talieps@cput.ac.za) the ability to generate high ball speeds has advantages in many reactive ball sports as it gives the opposition less time to respond. in cricket bowling, for example, faster deliveries reduce the batter’s decision-making and execution time of the stroke and increases the chance of the batter being beaten for pace.[1] surprisingly, there have been few studies investigating the effects of resistance training on ball release velocity in cricket.[2-4] furthermore, to our knowledge, there have been no studies demonstrating a meaningful increase (>5 km·h-¹) in ball release velocity (defined as the peak speed between ball release and ball bounce) in cricket pace bowlers following resistance training. in cricket, fast bowling has been related to both upper body and lower body neuromuscular performance.[5-6] higher shoulder extension strength was significantly positively correlated to ball release velocity,[5] while neuromuscular performance produced in the lower limbs were associated with increased ball release velocities.[7] during the bowling stride, large ground reaction forces have to be absorbed at front foot landing and powerful deliveries can be generated through leg extension, hip rotation, trunk flexion and shoulder rotation.[8] these studies collectively suggest that resistance training would be beneficial for improving ball release velocity. resistance training can broadly be categorised into three types: general, special and specific resistance training. general resistance training, which typically includes the use of free weights, weighted machines, bodyweight exercises and elastic tubing are designed to increase overall strength, and has significantly improved ball release velocity in baseball.[9] similarly, special resistance training, which is designed to develop power using explosive exercises, such as ballistic and plyometric exercises, has also been shown to improve throwing release velocity in the sport.[9] specific resistance training provides a training stimulus that mimics the body’s motions and bioenergetic systems that are used in an actual game setting.[10] the use of weighted implement training is a popular example and has shown to improve throwing velocity in baseball.[11] the theory behind the principles of overweight and underweight training can be derived from the force-velocity curve of movement, where resistance training occurs in the motion of the action performed. training with overweight balls is based on the principle of an overload of force (enhancing strength), whereas training with underweighted balls is based on the principle of an overload of velocity (enhancing speed).[10] two cricket bowling studies have investigated the use of specific resistance training on ball release velocity.[3-4] neither of these studies has shown a meaningful increase in ball release velocity. a meaningful increase is defined as the minimum worthwhile velocity of 5 km·h-¹, which is associated with the smallest change a top order senior club level batter would notice.[3] the combination of general, special and specific resistance (combined) would potentially produce better results. thus a combination of resistance training appears to improve a wider variety of athletic performance.[12] in cricket bowling, a combined resistance training programme was investigated on recreational bowlers over eight weeks.[2] the results revealed a 3 km·h-¹ increase in ball release velocity; however, there was also a significant decrease in bowling accuracy. bowling accuracy can be defined as the ability of a bowler to hit a predetermined vertical target, placed at the position of the cricket stumps.[2,13] cricket pace bowling performance is dependent on both speed and accuracy. despite the increase in ball release velocity, it would not relate to improved all-round bowling performance because of the loss of bowling accuracy. the decline in bowling accuracy could be due to the relative high mass of the heavier ball used during training (60% and background: despite the importance of resistance training for cricket pace bowlers, there is limited research displaying meaningful improvements in ball release velocity following resistance training. objectives: the study aimed at investigating the effects of a four weeks combined resistance training programme on ball release velocity in club cricket pace bowlers. methods: eighteen adult male club level pace bowlers were allocated into a combined resistance training (crt) group or a traditional cricket training (tr) group. the crt group (n=9) performed two training sessions a week for four weeks, consisting of a combination of core and lower body strength exercises, plyometric exercises, and weighted implement training. the tr group (n=9) did no resistance training and only bowled with regular weighted cricket balls. pretesting/post-testing variables were ball release velocity, bowling accuracy, and upper and lower body neuromuscular performance. results: the crt group significantly increased their ball release velocity by six percent (5.1 km·h-¹), effect size (es) =0.65, p<0.001) after four weeks of training, while there was no significant difference in the tr group (0.00 km·h-¹, es=0.0, p=0.674). there was no statistically significant difference in the bowling accuracy and lower body neuromuscular performance for both groups and the upper body neuromuscular performance for the crt group. conclusion: this study provides evidence of a combined resistance training programme that can be used to improve bowling velocity in cricket pace bowlers. this increase in ball velocity was not related to any of the neuromuscular performance variables measured. keywords: sport performance, weighted implement, neuromuscular performance, strength, speed s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a9002 mailto:talieps@cput.ac.za http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9002 https://orcid.org/0000-0003-3926-4700 https://orcid.org/0000-0001-9084-3148 original research sajsm vol. 33 no. 1 2021 2 92% respectively). when weighted balls are too heavy, it can negatively affect bowling accuracy and disrupt the bowling pattern.[4] this leads to inconsistent delivery release points and decreased bowling accuracy. if this is the case, it might be corrected by using underweight alongside overweight balls or decreasing the mass of the overweight balls utilised. at the elite level, cricket players have access to physical trainers and physical training resources, and their time can be dedicated to performance enhancement. however, at an amateur (recreational) club level, this will probably not be the case. recreational players are less likely to have the time available to do extra training at a gym because they may have a full-time job or are full time students, perhaps even with family responsibilities. others may have the financial resources to join a gym. therefore, to optimise training for amateur club players, utilising an effective resistance training programme that is cost effective in conjunction with their regular net practice sessions would be ideal. for this reason, combined resistance training could potentially produce the best results in the shortest period. previous pace bowling research using a combined resistance training programme showed a small increase in ball release velocity accompanied by a decrease in accuracy.[2] furthermore, the weighted implement training used in this study did not incorporate underweight balls. we therefore hypothesised that by utilising a combined resistance training and including relatively low to moderate over-and underweighted implements, it would increase the ball release velocity without affecting bowling accuracy, compared to participants that only perform traditional cricket training. methods participants eighteen male, club level (1st and 2nd division) cricketers were recruited for the study (table 1). all the participants had been injury-free for at least one month prior to the start of the study. a quasi-experimental design was employed. the participants were divided into a combined resistance training (crt) group (n=9) and a traditional cricket training (tr) (n=9) group. selection of players into the crt group was based on the coaches’ and players’ willingness to allow the training to occur in conjunction with their regular training. furthermore, the tr and crt groups were recruited such that no two players from different groups would see the other train. written informed consent was obtained from all participants prior to commencement of the study. the study had been approved by the authors’ institutional ethics review board (no. 2016fbrec359). the four-week programme consisted of a combination of general, special (table 2), and specific resistance training (table 3). the training programme coincided with the players’ regular cricket net training, which occurred twice a week. the weighted implement bowling occurred first, and thereafter, the general and special resistance training was completed. training sessions were separated by approximately 48 hours between sessions. general and special resistance exercises were based on prescribed exercises for cricketers and in line with strength and conditioning needs and training recommendations for pace bowlers.[14-15] the sport-specific bowling protocol utilised overweight, underweight and regular weighted cricket balls (specific resistance) (table 3). all overweight and underweight balls were professionally manufactured and cost the same as a regular weighted ball. participants in the tr group only bowled with regular weighted cricket balls (bowled the same number of balls as the crt group) and were instructed not to perform any resistance training during the four weeks of the study. the ball sequence, mass and number of balls bowled per session is presented in table 3. all participants played and bowled in one match per week (on a saturday) during the trial period. the bowling volume during matches was not controlled. measures the testing variables were ball release velocity, accuracy, and upper and lower body neuromuscular performance. participants were tested at baseline after the second and fourth week of training. the participants trained on tuesday and thursday afternoons and played matches on saturdays. testing either took place on a wednesday or monday afternoon, allowing a recovery period prior to testing. before each testing session, participants were required to complete a warm-up. the warm-up started with 20 m shuttle runs of progressive intensity and was followed by both dynamic and static stretching. the warm-up was individualised (each participant performed their own exercises that they usually perform prior to competition) but was standardised within participants between testing sessions. after this general warm-up, the participants bowled several deliveries beginning with light-intensity and progressing to high-intensity. the testing started once the players were satisfied that they were appropriately warmed up. participants were instructed to bowl six good-length deliveries (where the ball lands approximately 5 m from the batting crease) at their fastest speed while aiming to hit the top table 1. participant characteristics and testing variables at baseline crt group (n = 9) tr group (n = 9) p – value participant characteristics height (m) 1.78 ± 0.1 1.73 ± 0.1 0.231 mass (kg) 73.0 ± 8.3 77.0 ± 21.4 0.605 age (years) 22.6 ± 5.1 28.3 ± 7.7 0.078 resistance training experience (years) 0.8 ± 1.1 3.3 ± 4.6 0.131 pace bowling experience (years) 10.3 ± 5.5 12.0 ± 5.2 0.518 testing variables ball velocity (km.h-1) bowling accuracy (points) throw distance (m) jump height (cm) 91 ± 7 36 ± 15 5.4 ± 0.5 0.58 ± 0.1 87 ± 8 31 ± 26 4.9 ± 0.8 0.49 ± 0.1 0.301 0.628 0.141 0.105 data are expressed as mean ± sd. crt, combined resistance training group; tr, traditional cricket training group. original research 3 sajsm vol. 33 no. 1 2021 of the off stump after the bounce. however, no formal rating of perceived exertion was measured. the ball release velocity was measured using the stalker pro ii radar gun, which was placed on a tripod at the end of the participant’s run-up, behind the stumps. there is a maximum estimated error of 0.4% in ball release velocity when the radar gun is positioned behind the stumps (stalker pro ii; usa). the mean ball release velocity of six deliveries was recorded. bowling accuracy was measured using a vertical target grid system.[2,13] points were awarded according to where the target was hit, with a maximum of 100 points for a delivery hitting the equivalent of the top of the offstump. locations further away from the target received less points. the location of where the ball contacted the target grid was recorded with a high-speed video camera at 210 frames per second (casio exilim ex-fh20). bowling accuracy was calculated as the mean points of the six bowled with a regular weighted ball (156 g). upper body neuromuscular performance was measured using the seated medicine ball throw test. seated participants were instructed to push a 3 kg medicine ball from the chest up at approximately a 45° angle as forcefully as possible. no countermovement was allowed. participants were permitted three warm-up throws. the furthest distance of three attempts was recorded. lower body neuromuscular performance was measured by a countermovement jump test. the countermovement jump was conducted using the vertec jump (usa; california). participants were allowed three warm-up throws. thereafter, the highest of the three jumps was used for analysis. to increase adherence to the training protocol, the players’ coaches were familiarised with the exercises and the training protocol to assist and monitor the players. the investigator randomly visited the training sessions to further monitor the training. an attendance adherence of 96% was reported. statistical analysis statistical power for ball release velocity was conducted through a general linear model, repeated-measures analysis of variance, within-between factors (f test). a minimum of 18 participants were required for this study (nine per group). the alpha error probability was set to 0.05 and the power (1-β error probability) was 0.96 for the two groups with three repeated measurements (baseline, two weeks and four weeks). all data were first checked for normality (shapirowilk test), kurtosis, and skewness. all variables were approximately normally distributed. an independent samples t-test was conducted to ascertain if there were any between-group differences in participant characteristics at the pre-test period. the measurements of the crt and tr groups were compared using a general linear model, repeated measures (within-subjects) and the confidence interval were adjusted using the bonferroni correction. effect sizes (es) were reported by the hedge’s g statistic. the precision of mean differences was expressed with 95% confidence limits (95% cls). qualitative descriptors of standardised es using hedge’s g were assessed using the criteria: trivial, less than 0.2, small 0.2–0.49, moderate 0.5–0.79, and large 0.8. correlation between ball release velocity and the other testing variables were pooled for both groups and reported using the pearson r statistic. statistical significance for all tests was considered when p<0.05. results there were no significant differences in the participant characteristics between groups at baseline (table 1). the mean ball release velocity differed significantly after four weeks of training [f (2, 7) =51.5, p<0.001]. the ball release velocity increased in the crt group by an average of 4.2 km·h-¹ (95% [1.6, 6.7], es=0.52, p=0.003) after two weeks and a total increase of 6% (5.1 km·h-¹, 95% [3.7, 6.6], es=0.68, p<0.001) after four weeks of training (fig. 1a). this increase in ball release velocity was outside of the error measurement for the radar gun, thus table 2. summary of the four-week general and specific resistance training programme. sets were separated by 1 minute week exercise name type of resistance training reps x sets bodyweight squats general 10 x 2 bilateral hip raises general 10 x 2 bodyweight split squats general 6 x 2 1-2 chest passes special 6 x 2 recoiled overhead slams special 6 x 2 standing side tosses special 6 x 2 recoiled rotational shot puts special 6 x 2 bodyweight squats general 12 x 2 bodyweight split squats general 8 x 2 bilateral hip raises general 12 x 2 3-4 chest passes special 8 x 2 recoiled overhead slams special 8 x 2 hop back and throws special 8 x 2 step behind and throws special 8 x 2 table 3. ball mass and bowling sequence for the crt and tr group week ball sequence and mass (crt) ball sequence and mass (tr) balls bowled per session for each group 1-2 4 x 156 g (0%) 8 x 172 g (10%) 8 x 140 g (-10%) 4 x 156 g (0%) 4 x 156 g (0%) 8 x 156 g (0%) 8 x 156 g (0%) 4 x 156 g (0%) 24 (4 overs) 3-4 5 x 156 g (0%) 10 x 179 g (15%) 10 x 133 g (-15%) 5 x 156 g (0%) 5 x 156 g (0%) 10 x 156 g (0%) 10 x 156 g (0%) 5 x 156 g (0%) 30 (5 overs) overweight and underweight balls were rounded off to the nearest gram. ball mass above or below the normal mass are indicated as a percentage. crt, combined resistance training group; tr, traditional cricket training group. original research sajsm vol. 33 no. 1 2021 4 representing a true change in velocity by the bowlers. there was no significant difference in ball release velocity between two weeks and four weeks of training (0.97 km·h-¹, 95% [-1.4, 3.3], es=0.12, p=0.756) (fig.1a). there were no significant differences in the ball release velocity in the tr group across the four weeks [f (2, 7) =0.42, es=0.0, p=0.674] (fig. 1a). there was no significant difference between accuracy across the four weeks for both the crt [f (2, 7) =0.72, es=0.22 p=0.520] and tr groups [f (2, 7) =0.35, es=0.32, p=0.718] (fig. 1b). there was a non-significant increase in the throw distance across the four weeks [f (2, 7) = 2.2, es=0.36, p=0.179] in the crt group (fig. 1c). the tr group showed a significant increase in the throw distance across the four weeks ([f (2, 7) = 7.6, p=0.018]. the mean throw distance significantly increased between baseline and two weeks (0.24 m, 95% [0.02, 0.46], es=0.32, p=0.032) and between baseline and four weeks (0.33 m, 95% [0.08, 0.59], es=0.40, p=0.013) (fig. 1c). there was no significant difference in jump height across the four weeks for both the crt [f (2, 7) =0.42, es=0.15, p=0.762] and tr groups [f (2, 7) = 1.5, es=0.25, p=0.287] (fig. 1d). there was a statistically significant positive correlation between the countermovement jump height and ball release velocity (r=0.681, p=0.003). there was no statistically significant correlation between ball release velocity and medicine ball throw distance (r=0.238, p=0.342) or bowling accuracy (r=-0.400, p=0.100). discussion this study supports the hypothesis that a combined resistance training programme would increase ball release velocity in recreational cricket pace bowlers without a statistically significant decrease in bowling accuracy. in comparison with previous resistance training studies in other sports[9,11], the fig. 1. the change in ball release velocity (a), bowling accuracy (b), medicine ball throw distance (c) and countermovement jump height (d) for the crt and tr groups across the four weeks. crt, combined resistance training group represented by black bars; tr, traditional cricket training group represented by grey bars. a b d c original research 5 sajsm vol. 33 no. 1 2021 significant 6% increase in ball release velocity in four weeks is one of the largest increases in ball release velocity reported for such a short period of time, even when training recreational (club) participants. the non-statistically significant difference in both upper and lower body neuromuscular performance within the crt group suggests that the observed increase in the ball release velocity in the crt group was likely because of the weighted implement training. the advantage of performing weighted implement training is that it is a cricket bowling-specific method and optimises the full arm swing characteristic of cricket pace bowling; and strength gains are in accordance with the bowling movement. the increase in ball release velocity is likely due to a development of power in the arm, and shoulder complex and occurs through similar neural recruitment patterns during the bowling motion. the percentage weighted implements used in this study (10 -15%) appears to be beneficial to increase ball release velocity. previous cricket studies that have failed to show a meaningful increase in ball release velocity in cricket could be related to the percentage weighted implements used.[2-4] the weighted implement used in these studies may either have been too low (3% to 16%) over a 10-week period [3] or too high (46% to 137%) [4] and (60% to 92%) [2] over an 8-week period. there were non-significant variations in the mean age between the crt and the tr groups. the effect of age is unlikely to influence the trial results because resistance training responses have been found to be similar for adults irrespective of their age.[16] the crt group also had a nonsignificant lower resistance training age compared the tr group. these participants would potentially respond quickly to resistance training. however, previous studies that used relatively inexperienced resistance training participants[2] or untrained participants[9] reported small increases (3.7% and 1.7% respectively) in ball release velocity. the increase in the ball release velocity observed in the crt group was not at the expense of accuracy, which is a scenario frequently experienced in other studies of this nature.[2-3] the speed and accuracy relationship are of the utmost importance as a delivery with high velocity has little value if it is delivered with poor accuracy. therefore, the improvement in ball release velocity would positively affect its members’ bowling performance. previous studies reported a decrease in bowling accuracy.[2-3] the reason for the decrease in bowling accuracy by petersen et al.[3] could be related to the use of a target zone on a pitch. this system does not take the line of the delivery into account, rendering the validity of the accuracy measure open to question. the reason for the decrease in accuracy in the study by feros et al.[2] could be the large weighted implements used which could affect the bowling pattern, leading to inconsistent delivery release points and poorer bowling accuracy.[2,4] there was no significant increase in upper neuromuscular performance following training. these findings are similar to those of feros et al.[6] who found that the increase in ball release velocity was not associated with an increase in one rm pull up strength in cricket pace bowling. furthermore, the authors observed a weak correlation between the medicine ball toss distance and ball release velocity. feros et al.[6] similarly found a non-significant correlation between upper body neuromuscular performance and ball release velocity. both the crt and the tr groups showed an increase in throw distance after four weeks; however, only the tr was statistically significant (p=0.179 and p=0.032 respectively). furthermore, the magnitude of the effects was small for both the crt and tr groups (effect size of 0.36 and 0.40 respectively). the most likely explanation for this is that there was a learning effect. beckham et al.[17] discusses the importance of familiarisation for the seated medicine ball throw and highlights that several throws are required prior to testing. in this present study, participants were only allowed three warmup attempts prior to performing the test. the crt group and tr group increased by 29 cm and 24 cm respectively after two weeks. these authors therefore suggest that the increase in throwing distance is as a result of familiarisation to the test. the limitation of this testing protocol is that the throw scores were not monitored to determine if it was stabilised prior to testing. lower body neuromuscular performance did not significantly change across the intervention period. these results are similar to handball that reported no statistical significant change in lower body neuromuscular performance measured by the countermovement jump test, despite there being a significant statistical increase in throwing ball release velocity.[18] there was; however, a significant positive correlation between the countermovement jump height and the ball release velocity, indicating that the test utilised can be used as measure of neuromuscular performance associated with pace ball release velocity. previous research differed on the relationship between the countermovement jump test and ball release velocity. pyne et al.[7] found a significant positive correlation, while feros et al.[6] found a poor non-significant correlation. limitations there are a few limitations to consider with regard to the findings of this study. the limitation of combined resistance training is that there are a few independent variables that could have contributed to the increase in ball release velocity. despite our speculation that the weighted implement training largely contributed to the increase in ball release velocity, the exact contribution of the general, special and specific resistance training is unknown. a further limitation is that the trial was performed in-season and the influence of technical coaching on bowling biomechanics was not controlled for. biomechanical factors have been associated with pace bowling [19]; however, the influence of biomechanical training on ball release velocity still needs to be confirmed, particularly over a short period of four weeks. although all the participants reported that they played and bowled in matches during the study’s trial period, the volume of this bowling could not be controlled for due to the competitive nature of the game. it is; however, unlikely that if there were differences in the bowling volume that it would contribute to increased ball speeds because the participants were bowling with regular weighted balls and the magnitude of the difference would be relatively small compared to other studies where volume influenced ball release velocity.[20] original research sajsm vol. 33 no. 1 2021 6 another limitation is that the total training load between the crt and tr groups was not controlled for which could result in metabolic adaptations in the crt group. this study did not measure the batter’s perception of the bowler’s performance and therefore the practical application remains in question. future studies should investigate if a meaningful increase in ball release velocity is related to increased perceived difficulty in the batter’s response or a decrease in batting performance. conclusion this study provides evidence that the use of combined resistance training improved ball release velocity without having a detrimental effect on the bowling accuracy of club level pace bowlers. the training programme provides coaches and trainers with a cost-effective (only requirement is weighted balls and a 3 kg medicine ball) and time-efficient (can be incorporated with regularly net practice) solution to improve fast bowling performance at a club level. we recommend that approximately 40 balls per week be delivered with 10-15% weighted implement to improve fast bowling speed. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors would like thank dr corrie uys for her assistance in this project. author contributions: all authors were involved in conception, design, analysis and interpretation of data, drafting or critical revision for important intellectual content and approval of the version to be published. references 1. regan d. visual factors in hitting and catching. j sports sci 1997;15(6):533-558. [doi: 10.1080/026404197366985][pmid: 9486432] 2. feros sa, young wb, oʼbrien bj. efficacy of combined general, special, and specific resistance training on pace bowling skill in club-standard cricketers. j strength cond res 2020;34(9): 2596-2607. [doi:10.1519/jsc.0000000000002940] [pmid: 30741863] 3. petersen cj, wilson bd, hopkins wg. effects of modifiedimplement training on fast bowling in cricket. j sports sci 2004;22(11-12):1035–1039. [doi:10.1080/02640410410001729973] [pmid: 15801497] 4. wickington kl, linthorne np. effect of ball weight on speed, accuracy and mechanics in cricket fast bowling. mdpi sports 2017;5: 18. [doi:10.3390/sports5010018] 5. wormgoor s, harden l, mckinon w. anthropometric, biomechanical, and isokinetic strength predictors of ball release speed in high-performance cricket fast bowlers. j sports sci 2010;28(9):957-965. [doi:10.1080/02640411003774537][pmid: 20552518] 6. feros sa, young wb, oʼbrien bj. relationship between selected physical qualities, bowling kinematics, and pace bowling skill in club-standard cricketers. j strength cond res 2019;33(10):2812-2825. [doi:10.1519/jsc.0000000000002587] [pmid: 29702520] 7. pyne db, duthie gm, saunders pu, et al. anthropometric and strength correlates of fast bowling speed in junior and senior cricketers. j strength cond res 2006;20(3):620-626. [doi:10.1519/r-18315.1][pmid: 16937976] 8. johnstone ja, mitchell ac, hughes g, et al. the athletic profile of fast bowling in cricket: a review. j strength cond res 2014;28(5):1465-1473. [doi:10.1519/jsc.0b013e3182a20f8c] [pmid: 23897016] 9. escamilla rf, ionno m, demahy ms, et al. comparison of three baseball-specific 6-week training programs on throwing velocity in high school baseball players. j strength cond res 2012;26(7):1767-1781. [doi: 10.1519/jsc.0b013e3182578301] [pmid: 22549085] 10. van den tillar r. effect of different training programs on the velocity of overarm throwing: a brief review. j strength cond res 2004;18(2): 388–396. [doi:10.1519/r-12792.1][pmid: 15142008] 11. o’connell me, lindley ke, scheffey jo, et al. weighted baseball training affects arm speed without increasing elbow and shoulder joint kinetics. sportrxiv 2021. [doi:10.31236/osf.io/pzh8a] 12. harris gr, stone mh, bryant hs, et al. short-term performance effects of high power, high force, or combined weight-training methods. j strength cond res 2000;14(1):14-20. [doi:10.1519/00124278.200002000-00003] 13. phillips e, portus m, davids k, et al. performance accuracy and functional variability in elite and developing fast bowlers. j sci med sport 2012;15(2):182-188. [doi:10.1016/j.jsams.2011.07.006] pmid: 21907618] 14. cricket fitness n.d. cricket fitness: cricket fitness strength program: fitness level 1 routine http://www.cricketlab.co/ cricket-fitness-strength-program.html (accessed september 30, 2017) 15. mukandi i, turner a, scott p, et al. strength and conditioning for cricket fast bowlers. strength cond j 2014;36(6):96-106. [doi:10.1519/ssc.0000000000000099] 16. ahtianen jp, walker s, peltonen h, et al. heterogeneity in resistance training-induced muscle strength and mass responses in men and women of different ages. age (dordr) 2016:38(1):10. [doi: 10.1007/s11357-015-9870-1] [pmid: 26767377] 17. beckam g, lish s, keebler l, et al. the reliability of the seated medicine ball throw for distance. j phys act res 2019;4(2):131136 [doi:10.12691/jpar-4-2-9] 18. gorostiaga em, izquierdo m, iturralde p, et al. effects of heavy resistance training on maximal and explosive force production, endurance and serum hormones in adolescent handball players. eur j appl physiol occup physiol 1999;80(5):485–493. [doi:10.1007/s004210050622][pmid: 10502084] 19. portus mr, mason br, elliott bc, et al. technique factors related to ball release speed and trunk injuries in high performance cricket fast bowlers. sports biomech 2004; 3(2):263-83. [doi:10.1080/14763140408522845] 20. hermassi s, van den tillar r, khalifa r, et al. comparison of in-season-specific resistance vs. a regular throwing training program on throwing velocity, anthropometry, and power performance in elite handball players. j strength cond res 2015; 29(8): 2105–2114. [doi: 10.1519/jsc.0000000000000855] http://www.cricketlab.co/%20cricket-fitness-strength-program.html http://www.cricketlab.co/%20cricket-fitness-strength-program.html original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license accelerometery vs. video-derived stroke parameters in high-level swimmers c musson,1 ma; m kramer,2 phd 1 human movement science department, nelson mandela university, gqeberha, south africa 2 physical activity, sport and recreation (phasrec) unit, human movement sciences department, north-west university, potchefstroom, south africa corresponding author: c musson (courtney.musson@mandela.ac.za) optimal performance across sporting codes is typically based on the careful interplay between the athlete’s biomechanical, physiological and psychological factors on the one hand, and economic and social factors on the other.[1,2] for a bilateral and cyclical sport such as swimming, the most important parameter governing performance would be the optimisation of swimming velocity to complete a given race distance in the fastest time possible.[1] although the factors affecting swimming velocity are multifactorial (e.g. energetics, index of coordination, arm span, motivation, etc.), the maximisation of swim velocity is mostly dependent on the relationship between stroke length (sl) and stroke rate (sr).[1,3,4] both sl and sr are highly variable and are, in part, contingent on the stroke style utilised, namely freestyle, breaststroke, backstroke or butterfly.[3] it is traditionally the role of the coaches to keep a careful account of each of the parameters mentioned to improve the performance of their swimmers more effectively. for most coaches such a task is increasingly difficult and can often be imprecise due to the technical aspects that must be accounted for. the difficulty of the task may be compounded by the number of athletes each coach must deal with at any time.[5] the aforementioned challenges have created opportunities for the use of alternative technologies which may aid coaches in their tasks. such technologies include heart rate monitors, inertial measurement units, and accelerometers which can keep account of factors such as physiological effort and various swim kinematics.[6] accelerometers in particular have proven to be beneficial in swimming stroke and turning analyses, automatic stroke phase recognition[7] and performance feature extractions (e.g. stroke length).[8] therefore the use of accelerometery appears to be a viable and potentially low-cost option for providing coaches with technical support. despite this, there is currently limited research on: (i) the validity of accelerometers across different accelerometer types, and (ii) the utility of accelerometers to differentiate different stroke styles in highlevel swimmers. the objectives of the present study were therefore two-fold: (i) to determine the validity of parameters derived from a commercially available accelerometer compared to parameters derived from video analysis, and (ii) to identify kinematic differences in stroke styles using accelerometer-derived data in high-level swimmers. methods study design this study used a one-group posttest-only design. the rationale for such a design was that the principle parameters of interest were related to the validity of the accelerometers across different swim strokes and swim distances. participants a total of 12 south african national level swimmers from different swim clubs volunteered for this study. to be included, swimmers must have represented at a national level (e.g. junior nationals, youth nationals, youth elite or senior national level), and have been free of injury prior to testing. based on the latter criterion, the sample group was comprised of five male (age: 22.2 ± 2.6 years; height: 1.84 ± 0.08 m; weight: 76.2 ± 3.6 kg; national swim experience: 6.1 ± 3.0 years) and seven female (age: 20.7 ± 2.1 years; height: 1.68 ± 0.08 cm; weight: 62.0 ± 6.3 kg; national swim experience: 7.1 ± 2.5 years) swimmers. this study was conducted according to the guidelines of the declaration of helsinki and all procedures were approved by the institutional research ethics committee (h18-hea-hms007). all swimmers were required to provide written informed background: swimming is a multifaceted sport with nuanced performance parameters that tend to vary according to the swimmer’s stroke style. the extraction and analyses of swim parameters, such as lap time (lt), stroke length (sl), stroke rate (sr) and velocity are time-consuming. this may be eased and to some extent automated by the use of cost-effective triaxial accelerometers. objectives: to determine the validity of tri-axial accelerometers across all four stroke styles, and to investigate kinematic differences in stroke styles using accelerometerbased data. methods: twelve elite swimmers were recruited for the study. the group consisted of five male (age: 22.2 ± 2.6 years; height: 1.84 ± 0.08 m; weight: 76.2 ± 3.6 kg) and seven female (age: 20.7 ± 2.1 years; height: 1.68 ± 0.08 cm; weight: 62.0 ± 6.3 kg) swimmers. results: there was a small but significant bias for accelerometery data compared to video data across most parameters and stroke styles except for stroke length and stroke count (p > 0.05). however, accelerometery-derived sr, sl and velocity can be considered practically useful based on the training requirements of coaches. parameters derived from video analysis compared to accelerometery were highly correlated (r > 0.91) and therefore consistent regardless of the method of analysis. conclusion: although slight differences were present between the video and accelerometer data, these differences were not practically meaningful. keywords: accelerometers, elite swimmers, kinematics, video analysis s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a9483 mailto:courtney.musson@mandela.ac.za http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9483 https://orcid.org/0000-0002-0875-6190 https://orcid.org/0000-0003-2237-7549 original research sajsm vol. 33 no. 1 2021 2 consent after having received all necessary instructions related to the study. instructions to participants included: (i) no consumption of alcohol or caffeine 48 hours prior to testing, (ii) avoiding strenuous exercise 48 hours prior to testing, and (iii) arriving for testing well hydrated, but two to three hours postprandial. data collection participants visited the testing facility on two separate occasions during their pre-season training period. the first visit was for completing informed consent forms and familiarisation with the equipment setup. the second visit, separated from the first by 24-48 hours was used for recording: (i) anthropometric data, such as height (m), weight (kg) and arm span (m), and (ii) the swim assessment which consisted of a 4 x 50 m individual medley (im) completed in a 25 m indoor pool (water temperature: 25-27oc). the im consists of the consecutive completion of all four swimming strokes in a pre-specified order, namely butterfly, backstroke, breaststroke and freestyle. prior to testing, participants were fitted with two tri-axial accelerometers (geneactiv, activeinsights, uk; sampling at 100 hz) worn on the left wrist and strapped to the upper back of the torso, as well as a heart rate monitor (polar h7, kempele, finland). once fitted, participants were instructed to complete a self-paced warm-up lasting five minutes, followed by a five minute cooldown period to have physiological values return to baseline. for the im, all participants completed all four strokes, regardless of stroke specialisation. participants were also instructed to swim at a slow to medium pace as they were video recorded with a custommade two-camera-trolley system that allowed for video recording from below (gopro 4, gopro inc., san mateo, california, united states) and perpendicular to (sony cybershot dsc-rx10 mk iii, sony electronics inc., new york, united states) the line of travel. both video cameras recorded at 100 hz which allowed for 1:1 synchronisation with the triaxial accelerometers. parameter calculations accelerometer data were downloaded and exported for analysis in originpro (originlab, version 2019b, usa), where data were filtered using a low-pass fourth order, zero-lag butterworth filter with a cut-off frequency of four-six hz. depending on the stroke, two different axes were used to extract the kinematic parameters, dictated by the primary plane of movement used by the swimmer during the execution of the stroke. for the freestyle and backstroke, the z-axis from the wrist accelerometer provided information related to stroke count, whereas the xand z-axes from the trunk accelerometer provided information related to lap times (see fig. 1). conversely, for the breaststroke and butterfly, the y-axis from the wrist accelerometer provided information related to stroke count, whereas the xand y-axes provided information related to lap times. for video data, the completed lap times were recorded as the duration from the start signal to when the hand touched the wall at the end of the final stroke. for accelerometer data, the completed lap times were derived from the y-axis of the chest unit, where there was a deviation away from 1g (start), and when the acceleration would return to 1g; which would occur when the torso was upright (see green plot in fig. 1). the relevant peaks and troughs from the accelerometers were analysed using specialised peak-finding algorithms (originpro, originlab, version 2019b, usa) which could then be used to table 1. descriptive statistics of accelerometer-derived and video-derived kinematic parameters for all swim strokes parameter freestyle butterfly breaststroke backstroke accel video accel video accel video accel video stroke count (n) 18.17 ± 3.9 18.00 ± 3.93 22.75 ± 4.69 22.92 ± 4.46 19.50 ± 5.30 19.17 ± 5.67 16.92 ± 3.12 16.83 ± 2.76 stroke length (m.stroke-1) 2.89 ± 0.60 2.90 ± 0.58 2.30 ± 0.49 2.29 ± 0.48 2.78 ± 0.78 2.78 ± 0.80 3.09 ± 0.58 3.06 ± 0.48 stroke rate (stroke.s-1) 0.37 ± 0.09 0.39 ± 0.09 0.47 ± 0.10 0.50 ± 0.10 0.37 ± 0.08 0.38 ± 0.09 0.33 ± 0.07 0.34 ± 0.06 velocity (m.s-1) 1.03 ± 0.07 1.08 ± 0.07 1.04 ± 0.09 1.10 ± 0.10 0.96 ± 0.08 1.01 ± 0.09 0.99 ± 0.08 1.02 ± 0.10 lap time (s/25 m) 24.44 ± 1.56 23.18 ± 1.46 24.29 ± 2.22 22.76 ± 2.05 26.40 ± 2.30 24.84 ± 2.23 25.46 ± 1.92 24.29 ± 2.12 data are expressed as mean ± sd. accel, accelerometer. fig. 1. tri-axial accelerometer data from the wrist and trunk of a representative athlete for the 50 m (2 x 25 m) backstroke component during the individual medley (im). original research 3 sajsm vol. 33 no. 1 2021 calculate parameters such as sr, average sl and average swim velocity. comparisons between the videoand accelerometer data could then be made. parameters were calculated using the following equations which would be applied to both videoand accelerometerderived parameters: average swim velocity (m/s) = distance (m) / lap time (s) [1] average stroke rate (stroke/s) = number of strokes (n) / lap time (s) [2] stroke length (m/stroke) = average swim velocity (m/s) / sr (stroke/s) [3] statistical analysis all data are presented as means ± standard deviation (sd) unless otherwise stated. data were assessed for normality using the shapirowilk test with the level of significance set at 0.05. for the first objective, a blandaltman analysis was performed to determine the bias and limits of agreement (la), with 95% confidence intervals (ci95%), between the video (criterion) and accelerometer (alternative) parameters (i.e. lap time, sl, sr, velocity and stroke count). a correlation analysis was used to show the magnitude and direction between accelerometerand video-derived parameters and the relationship between these parameters where the absolute value of the correlation coefficient was interpreted as follows: trivial: < 0.10, small: < 0.30, moderate: < 0.50, large: < 0.70, very large: < 0.90, almost perfect: ≤ 1.00.[9] for the second objective, the two one-sided t-test (tost) analysis for paired data was used to assess whether fig. 2. correlation matrix of kinematic parameters across all stroke styles. a, accelerometer; v, video; sl, stroke length; sr, stroke rate; vel, velocity; lt, lap time, sc, stroke count. upper triangular portion shows the confidence magnitude and direction of the relationship (* denotes statistical significance). lower triangular portion shows the correlation coefficients. table 2. summary of bland-altman statistics between the accelerometerand video-derived kinematic parameters for all stroke styles parameter bias estimate [ci95] lower la [ci95] upper la [ci95] p-value freestyle velocity (m.s-1) -0.05 [-0.07, -0.02] -0.13 [-0.18, -0.08] 0.04 [-0.01, 0.09] 0.005* stroke length (m.stroke-1) -0.01 [-0.12, 0.09] -0.35 [-0.54, -0.16] 0.32 [0.13, 0.51] 0.778 stroke rate (strokes.s-1) -0.01 [-0.03, -0.00] -0.05 [-0.08, -0.03] 0.03 [0.01, 0.05] 0.083 lap time (s) 1.26 [0.69, 1.84] -0.51 [-1.51, 0.50] 3.03 [2.02, 4.04] <0.001* stroke count (n) 0.17 [-0.36, 0.70] -1.47 [-2.40, -0.54] 1.80 [0.87, 2.74] 0.504 butterfly velocity (m.s-1) -0.06 [-0.09, -0.04] -0.14 [-0.19, -0.10] 0.02 [-0.03, 0.06] <0.001* stroke length (m.stroke-1) 0.01 [-0.03, 0.05] -0.11 [-0.18, -0.04] 0.13 [0.06, 0.19] 0.674 stroke rate (strokes.s-1) -0.03 [-0.04, -0.01] -0.07 [-0.10, -0.05] 0.02 [0.01, 0.04] 0.002* lap time (s) 1.53 [1.09, 2.00] 0.19 [-0.56, 0.95] 2.86 [2.10, 3.61] <0.001* stroke count (n) 0.17 [-0.41, 0.08] -0.93 [-1.37, -0.49] 0.60 [0.16, 1.03] 0.166 breaststroke velocity (m.s-1) -0.06 [-0.07, -0.05] -0.10 [-0.13, -0.08] -0.02 [-0.04, 0.01] <0.001* stroke length (m.stroke-1) -0.01 [-0.08, 0.07] -0.24 [-0.38, -0.12] 0.23 [0.10, 0.37] 0.870 stroke rate (stroke.s-1) -0.02 [-0.03, -0.00] -0.05 [-0.08, -0.03] 0.02 [0.00, 0.04] 0.018* lap time (s) 1.56 [1.28, 1.85] 0.68 [0.18, 1.18] 2.45 [1.94, 2.95] <0.001* stroke count (n) 0.33 [-0.08, 0.75] -0.94 [-1.67, -0.22] 1.61 [0.88, 2.34] 0.104 backstroke velocity (m.s-1) -0.03 [-0.06, -0.01] -0.11 [-0.16, -0.67] 0.05 [0.00, 0.09] 0.019* stroke length (m.stroke-1) 0.03 [-0.06, 0.13] -0.26 [-0.43, -0.09] 0.33 [0.16, 0.50] 0.458 stroke rate (strokes.s-1) -0.01 [-0.02, 0.00] -0.04 [-0.06, -0.03] 0.02 [0.00, 0.04] 0.047* lap time (s) 1.17 [0.61, 1.73] -0.57 [-1.56, 0.42] 2.93 [1.91, 3.89] <0.001* stroke count (n) 0.08 [-0.34, 0.51] -0.12 [-1.97, -0.48] 1.39 [0.65, 2.14] 0.674 * indicates significance (p<0.05); ci95, 95% confidence interval; la, limits of agreement. original research sajsm vol. 33 no. 1 2021 4 differences between accelerometer-derived vs. video-derived parameters were statistically equivalent and therefore practically meaningful. equivalence bounds were based on raw scores, with uncertainty in the point estimates for the mean difference being presented as 90% confidence intervals (two-sided test). [10] through careful discussion with coaches, the equivalence bounds were set at a given deviation from zero: velocity = ± 0.10 m.s-1 (i.e. within ~ 0.5 km.hr-1), sr = ± 0.04 strokes.s-1 (i.e. within ~ 2-3 strokes.min-1 [or ~ 0.03-0.05 strokes.s-1]), sl = ± 0.02 m.stroke-1 (~ 20 cm.stroke-1, being essentially equivalent to ~ 1 hand span), lt = ± 1.50 s. the statistical analyses were completed using microsoft excel (microsoft corporation, usa) and originpro (originlab, version 2019b, usa). results the summary statistics (m ± sd) of key swim parameters for each of the four different stroke styles derived from both accelerometers and video analysis are presented in table 1. the correlations between accelerometer-derived and videoderived parameters are shown in figure 2. the parameters of interest were pooled for all stroke styles to provide an overview of the magnitude and direction of the relationship between accelerometer and video data. irrespective of stroke style, there was evidence of statistically significant bias (i.e. mean difference away from zero) between accelerometervs. video-derived parameters for average swim velocity (n=48, bias = -0.05 m.s-1, ci95 [-0.06, -0.04], p < 0.001), sr (n=48, bias = -0.02 str.s-1, ci95 [-0.02, -0.01], p < 0.001), and lt (n=48, bias = -1.38 s, ci95 [1.16, 1.60], p < 0.001) (see table 2 for individual stroke style data). across all styles, no statistically significant differences were evident for sl (n=48, bias = 0.00 m.str-1, ci95 [-0.03, 0.04], p = 0.795) or stroke count (n=48, bias = 0.10, ci95 [-0.09, 0.30], p = 0.280). the discrepancies between videoand accelerometer data for the first three parameters are thought to be due to errors from the accelerometer data with regards to the identification of the turning points for each lap within the im. such errors would affect the calculated lap durations which in turn would affect calculations such as the average swim velocity and sr. based on the equivalence bounds set by the coaches, it is clear that the differences between videoand accelerometer parameters fell well within the equivalence bounds for swimming velocity, sr and sl (see fig. 3, panels a-c). the lt however would be significantly over-predicted by the accelerometers compared to the video data (see panel d, fig. 3). since accurate accelerometer-based lt identification was based on an upright torso at the end of a lap, any delay in getting the torso upright would lead to an overestimation in lt compared to video analyses. fig. 3. tost results showing the mean difference (mdiff) with ci90 error bars between accelerometer and video parameters for velocity (panel a), stroke rate (sr: panel b), stroke length (sl: panel c) and lap time (panel d). the predetermined region of equivalence is shown in grey, with the lower and upper bounds being shown by dotted vertical lines. the zero line is shown by the solid vertical line. original research 5 sajsm vol. 33 no. 1 2021 discussion the main finding of the present study was that although the accelerometer-derived parameters showed statistically significant bias compared to video-derived parameters, the primary variables of interest (i.e. sl, sr, and velocity) were well within the confidence bounds of what would be considered practically meaningful. furthermore, the authors have provided an overview of the kinematic parameters of all four stroke styles for high-level swimmers and how these compare when derived from either accelerometeror videobased analyses. although statistically significant, bias between videoand accelerometer data were present, implying that the accelerometers may not be considered a ‘true’ surrogate for video data. the data derived from these units are still considered practically useful for coaching and training purposes. the accelerometers used in the present study also show potential utility for monitoring swimming performance for multiple athletes during training across all stroke styles. while certain commercially available activity monitors include the capability to detect stroke events, these are typically limited to only a few strokes and show similar errors to those observed in the present study[11], thereby potentially motivating the use for more specialised accelerometery devices. the automated monitoring of swim training is considered an important component of performance improvement. as the training season progresses, swimmers usually experience changes in stroke length, enhanced stroke efficiency, as well as decreased lap times.[3] fluctuations in key performance parameters would require the regular, repeated monitoring and analysis by coaches, which would be considerably more difficult and time-consuming with larger athlete cohorts.[12] video analysis is typically an attractive option; however, a key disadvantage of quantitative video analysis relates to the time taken to manually digitise footage (e.g. 7-27 hours depending on athlete count and analysis complexity), which is often coupled with a higher probability for introducing human error.[12,14] although automation of the digitisation process is continuously evolving, it requires the procurement of multiple cameras, sophisticated software and placement of key anatomical markers, the combination of which would disproportionately increase costs, decrease viability and may inadvertently affect the swimmers’ kinematics.[12] the use of affordable technologies, such as tri-axial accelerometers (~r 3000), may be a considerable benefit in monitoring training progression that would also substantially decrease analysis time and enhance the reliability of athlete feedback.[5,12,13] the present study has shown that accelerometer data is not only a viable alternative, but also highly correlated with video data (r >0.91). the accuracy of the results obtained here are on a par with those of other studies, even though the sample investigated was different.[12,13] furthermore, key kinematic parameters evaluated in the present study, such as swim velocity, sr, and sl, are practically equivalent between both methods of analysis which enhances the real-world utility of such devices. although accelerometery undoubtedly shows promise as a measurement and analysis tool, certain factors, such as qualitative technical aspects, cannot yet be derived from accelerometery alone. until such a time that the nuanced details of the swim stroke can be parameterised with accelerometery using more powerful and versatile algorithms, it is highly probable that video analysis, although cumbersome, will continue to remain a central component of a holistic swimming analysis. a logical next step would be to evaluate: (i) whether the accelerometers and algorithms used in the present would apply beyond the distances and athletic cohort used in the present study, (ii) differences across different swimming speed profiles (i.e. long, slow distance vs. sprint swimming), and (iii) differences in stroke technique within a given swim stroke. the evaluation of longer distances is primarily limited by the video technology as this would need to be available for data validation. [6,14] in their study, ganzevles et al.[13] found that the 1200 m distance yielded reliable and accurate results although the accurate detection of finishing time was still problematic. similarly, changes in the acceleration profile of the wrist, considered a proxy for swimming intensity, would change the parameter extraction and may therefore change the accuracy of the algorithm for detecting key aspects of a stroke.[6] in the present study a slow stroke rate was purposefully utilised due to the complexities of the data collection process. ganzevles et al.[13]; however, noted that higher stroke rates tend to lead to a greater spread in the accelerometer data which may be attributed to a greater number of irregularities in the stroke rhythm. finally, although each stroke exhibits similarities in the acceleration profile across athletes, it is important to note that athletes do exhibit subtle differences in stroke phase durations and hand/wrist placement during a given stroke.[15] such differences may introduce subtle nuances in the acceleration profile that may affect the accuracy of timing information derived from accelerometers. future research should therefore focus on specific feature extraction within the acceleration profile and track this across a swimming season and see whether the acceleration profile is sensitive to the effects of an intervention. limitations several limitations were present in this study. the overall swim velocity was restricted to ensure that two-dimensional video data could adequately capture the full stroke profile of the swimmer. longer swim distances were omitted as the validity of the accelerometers across stroke styles was unknown; therefore, whether the data transfers to longer swim distances is presently not verified. the sample used in the present study was homogenous (i.e. elite), therefore whether kinematic parameters can be easily identified for non-elite and/or recreational swimmers is presently unknown on the basis that stroke kinematics may be more varied. future research should investigate whether accelerometery could be used to extract more nuanced features related to stroke mechanics, such as in-sweep, out-sweep and recovery times to provide even more useful information for the coach. a further limitation relates to the fact that these authors generalised the equivalence bounds across all swim strokes to original research sajsm vol. 33 no. 1 2021 6 assess the practical utility of the accelerometers as a whole; and they do acknowledge that the bounds for each parameter may change depending on the stroke style and this should be considered in future. finally, all analyses in the present study were post hoc, and therefore future research should investigate whether instantaneous data streaming would be possible, as this may be more meaningful for the coach and/or athlete by providing immediate, rather than delayed, feedback. conclusion accelerometers are a meaningful tool for monitoring swimming kinematics across different stroke styles. although slight differences were present between video and accelerometer data, they were not practically meaningful. the accelerometers used in the present study therefore show promise as a training monitoring tool on the basis that they are affordable, show high correlation and practical equivalence for key parameters, such as swimming velocity, sr, sl and sc. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the researchers would like to thank all the athletes for their whole-hearted participation and effort throughout the study. they would also like to thank emma thomas, josh du preez and david-john lilford for their help during the data collection process. author contributions: cm conceived the study. cm and mk conducted the study, gathered and analysed the data, and wrote the manuscript. references 1. figueiredo p, pendergast dr, vilas-boas jp, et al. interplay of biomechanical, energetic, coordinative, and muscular factors in a 200 m front crawl swim. biomed res int 2013;6:1–12. 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[http://dx.doi.org/10.3390/ s150511363] [pmid: 26007718] original research 1 sajsm vol. 29 2017 a 12-week primary prevention programme and its effect on health outcomes (the sweet hearts biokinetics pilot study) r w evans,1mphil; d j hume,1phd; m h noorbhai,2phd; hg l rauch,1phd; n van der schyff,3md; e v lambert,1phd 1division of exercise science and sports medicine, department of human biology, faculty of health sciences, university of cape town, newlands, 7725, south africa 2department of sport management, faculty of business and management sciences, cape peninsula university of technology, mowbray, 7925, south africa 3victoria hospital, alphen road, wynberg, 7780, cape town, south africa corresponding author: rw evans (robertevanssa@gmail.com) non-communicable diseases (ncds) are noninfectious, chronic conditions that are typically lifestyle-related, and are generally treatable via health promotion and structured behaviour modification.[1] ncds typically progress at a slow rate and include (but are not limited to) cardiovascular disease, various types of cancer, chronic respiratory diseases, metabolic dysfunction, and type 2 diabetes mellitus. the predominant causes of mortality globally are from ncds.[2] physical inactivity is recognised internationally as a major independent and modifiable risk factor contributing to the worldwide rise in ncds. currently more than 50% of adults within south africa are physically inactive.[2] based on the south african demographic and health survey (sadhs) data collected in 1998, bradshaw et al. identified that an alarming number of ncds are attributable to physical inactivity among south africans.[1] for example, in this country, physical inactivity is implicated in 30% of patients with ischaemic heart disease and in 20% of those presenting with type 2 diabetes mellitus. the south african summit on the prevention and control of ncds, held in 2011, reached a formal consensus identifying the need for an intensified national plan stressing prevention, early detection, behavioural change and the nationwide treatment of ncds. emerging from this meeting, the strategic plan for the prevention and control of non-communicable diseases 20132017 developed by the south african department of health (doh) outlines three main public health strategies: 1) prevent ncds and promote health and wellness at population, community and individual levels; 2) improve control of ncds through the strengthening and reform of health systems; and 3) the monitoring of ncds and their main risk factors, as well as conducting innovative research.[2] in order to assist with the attainment of the doh’s goals, a 12-week pilot biokinetics primary prevention programme the sweet hearts study was initiated. the problem of physical inactivity is further compounded by the fact that half or less of individuals fail to adhere to exercise programmes over the long-term or before significant health benefits can be realised.[3] notably, evidence suggests that people from low-income groups, such as those reliant on the public health sector, are more difficult to identify and successfully recruit for guided lifestyle modification.[3] examples of non-adherence are well documented by scarinci et al. [4] where 45% of participants were lost to follow-up. as such, strategies to promote adherence must be incorporated into the initial design of physical activity interventions if they are to have a meaningful impact on the people they serve. numerous lifestyle modification programmes negate the social, political, cultural and economic forces that shape individual choices in their daily lives. a potential solution for this is the social-ecological model, which incorporates several lateral influences and acknowledges the value and complexities of creating an environment which promotes physical activity.[5] the social-ecological model was thus implemented during the conceptualisation and execution of this project, the findings of background: the prevalence of non-communicable diseases (ncds) and physical inactivity are concerning within the south african population. to address these concerns, the ‘strategic plan for prevention and control of ncds 2013-2017’ was developed. in response to this plan, a 12-week pilot biokinetics community health programme, sweet hearts, was initiated. methods: this study is a prospective pilot study evaluating the feasibility and effectiveness of the intervention. twentyfive individuals participated in the intervention. ten participants performed a battery of physiological tests pre and post intervention and 5 participants completed an email-based survey post intervention. the setting of the study was tramway football club, southfield, cape town, south africa. the sweet hearts intervention was designed to promote physical activity and healthy nutritional habits in those who participated. a total of 27 exercise sessions consisting of cardiovascular, resistance and flexibility training were conducted. brief-behavioural counselling was integrated into exercise sessions. results: the intervention group had a high attrition rate with >50% of participants not presenting for post-intervention testing. results were evident despite a limited sample size. there were significant improvements in health outcome measures among participants who did attend all testing sessions. these improvements included: an increase in global physical activity questionnaire (gpaq) score (p = 0.03), 12minute walk distance (p = 0.01), sit-to-stand test repetitions (p = 0.001), and a decrease in waist circumference (p = 0.01). improvements were also noted in self-reported eating restraint (p = 0.03). five main themes were structured into post intervention surveys: 1) enjoyment of the intervention, 2) benefits of the intervention, 3) obstacles affecting adherence, 4) future improvements to the intervention, and 5) state of non-communicable diseases in south africa. conclusion: the results of the sweet hearts intervention demonstrate the difficulty and importance of maintaining adherence to a community health intervention. the favourable results of the small sample size demonstrate the potential benefit of biokinetics-based programmes in the public health sector; and provide proof of concept for the dedication of resources towards health promotion within a community setting. keywords: non-communicable diseases, physical inactivity, public health, community intervention, adherence s afr j sports med 2017;29:1-7. doi: 10.17159/2078-516x/2017/v29i0a1346 mailto:robertevanssa@gmail.com http://dx.doi.org/10.17159/2078-516x/2017/v29i0a1346 original research sajsm vol. 29 2017 2 which are discussed in this context. in the present study, a pilot physical activity-based community health intervention programme was implemented. the intervention was developed as a response to the call by evans et al. [6] for the inclusion of biokinetics into the south african public health system and furthermore, to act upon the recommendations set out in the strategic plan for the prevention and control of ncds 2013-2017. the primary goals of the intervention were to (a) increase the physical activity levels of participants and (b) promote improved lifestyle choices including healthy eating and stress reduction. in addition, participants completed a post-intervention survey to capture qualitative data so as to elucidate subjective experiences throughout the intervention. methods study design in this prospective pilot study, participants were enrolled in a 12-week physical activity-based programme. they were assessed at baseline and at the end of the 12-week programme. the testing protocol included health screening, aerobic and muscular endurance, various health-related questionnaires and a semi-structured survey retrospectively evaluating the subjective experiences of the programme. the study was conducted with approval from the faculty of health sciences human research ethics committee (hrec ref 214:2012; 467:2015), university of cape town, south africa. tramway football club in southfield, cape town, served as the venue for the study. southfield is one of cape town’s southern suburbs. ncds account for a total of 31% of yearsof-life-lost in the southern suburb’s populations.[7] the large prevalence of ncds in these populations made it an appropriate setting for a community lifestyle intervention. participants twenty-five participants (22 females, 3 males) were recruited from the community into the 12-week intervention via radio announcements, flyers and emails. participants were excluded on the grounds of orthopaedic injury presentation, or possessing ≥ two risk factors* based on the american college of sports medicine (acsm) risk stratification categories for cardiovascular disease.[8] measurements testing was conducted by qualified and intern biokineticists with the assistance of the biokinetic humanitarian project (bhp).[9] questionnaires on the first day of testing, participants completed an informed consent form and acsm pre-participation * a review of risk assessment and physical activity clearance by thomas et al. [16] provides evidence that ordinarily ‘high-risk’ individuals (≥ 2 acsm risk factors) who are medically stable, partake in physical activity, and have adequate physical ability, should participate in medically-supervised physical activity interventions of low-to-moderate risk. based on these recommendations, the on-site questionnaire designed to identify any factors that indicate a risk of participation in exercise. participants then completed self-report questionnaires1** designed to measure their subjectively quantified physical activity level (global physical activity questionnaire), demographics, eating habits (threefactor eating questionnaire), tobacco use and resilience (cdrisc). the three-factor eating questionnaire (tfeq) is a 51item survey that measures three dimensions of human eating behaviour: cognitive eating restraint (the tendency to restrict food intake to control body weight), disinhibition (a sporadic loss of dietary control in the form of increased frequency and/or volume of food intake), and hunger (a measure of whether appetite primarily drives food intake, and the extent to which the individual engages in emotional eating). higher scores indicate greater degrees of cognitive restraint, uncontrolled eating, or hunger. the tfeq and its modified versions have been shown to be valid measures of these habitual eating behaviours in healthy populations.[10] brief behavioural counselling was performed with participants to establish individualised and achievable goals whilst participating in the intervention. qualitative measurements were conducted upon completion of the 12-week programme which involved a self-developed open-ended survey. this structure was used to ensure all pertinent topics were covered, whilst also further allowing the participant to discuss a wide range of issues. a purposive sampling technique was used to select participants for the email-based survey. of the total of ten participants who completed the intervention, five agreed to complete the survey. anthropometry and health screening participants’ stature (seca stadiometer, seca, usa), body mass (clover scale, model tcs-a300, south africa), waist circumference (standard non-elastic tape measure), blood pressure (manual), blood glucose (accu-chek, roche diagnostics, usa), resting heart rate (manual) and the thickness of seven skinfolds (harpenden caliper, holtain ltd, bryberian, crymmych, pembrokeshire) were then measured. aerobic capacity and muscular endurance participants then performed a one-minute lower body muscle endurance test and a 12-minute walking test[11] where they were encouraged to walk as far as possible in 12 minutes. the lower body muscle endurance test involved sitting to standing from a chair as many times as possible in 60 seconds. this testing protocol was also repeated after the 12-week intervention. intervention a total of 27 exercise sessions, 60 minutes in duration, were conducted during the 12-week intervention. sessions were held on monday and wednesday evenings. all sessions were medical doctor assessed those who still wished to participate but would ordinarily be excluded according to the acsm criteria. participants were included if it was deemed the benefits they stood to gain from the study outweighed the risks of participation. no adverse events occurred during the course of the intervention. ** references pertaining to questionnaires used are available on request from the corresponding author. original research 3 sajsm vol. 29 2017 planned and conducted by intern biokineticists completing their final year of practical training and were supervised by two qualified biokineticists. each session progressed from low to moderate intensity (approximately 40-70% vo2max) and contained a combination of strength, cardiovascular and flexibility training. exercises were conducted on an open field and basic equipment, such as cones, skipping ropes, elastic resistance bands and medicine balls, were used. examples of exercises prescribed included push-ups, squats, elastic rows, pelvic bridges, repeat sprints, agility drills, medicine ball throws, hamstring stretches etc. brief behavioural counselling was conducted during warm up and cool-down periods. the counselling addressed pertinent lifestyle issues, such as physical inactivity, smoking and eating behaviours. intern biokineticists were trained in basic life support and a medical doctor was either on-site or on emergency call. statistical analysis the statistica 12 software package was used for all analyses. quantitative analysis was performed on the ten participants completing the intervention while qualitative analysis was performed on the five participants who agreed to partake in the survey. a goodness-of-fit model was used to confirm that data were parametric. descriptive statistics were performed and reported as means ± standard deviations. inferential statistics (student t-tests) were utilised to detect differences between participants at baseline and post-intervention. the alpha level was set at p < 0.05. survey results were manually colour-coded for content in order to determine common themes. results quantitative results twenty-five individuals were initially enrolled in the study with an average attendance of 56% across all sessions. of these, ten participants (all females) made themselves available for post-testing with an average attendance of 72% (table 1); a minimum attendance rate of 60% was required to be included in the final analysis. variables at baseline were equivalent in those presenting for post-testing versus those who did not; except for a significantly higher resting heart rate (p = 0.01) and significantly lower resting breathing rate (p = 0.04) in those who could not attend the post-testing session. significant changes occurred in the following basic physiological variables (p ≤ 0.05): an increase in the global physical activity questionnaire (gpaq) score from 689 ± 791 to 2760 ± 2523 met-minutes/week (t(8) = 2.57, p = 0.03), an increase in 12-minute walk distance from 1360 ± 353 to 1565 ± 220 meters (t(9) = 3.15, p = 0.01), an increase in the number of sitto-stands from 35.8 ± 6.3 to 42.5 ± 3.4 repetitions (t(9) = 4.61, p = 0.001), and a decrease in waist circumference from 85.9 ± 15.4 to 80.8 ± 11.4cm (t(9) = -3.2, p = 0.01). a summary of changes in basic physiological variables is contained in table 2 below. scores on the three-factor eating questionnaire showed favourable changes across dietary restraint, disinhibition and hunger scores (table 3). however, only the increase in restraint reached a level of significance (t(9) = 2.51, p = 0.03). qualitative results five primary themes were structured into the survey: 1) enjoyment of the intervention 2) benefits of the intervention 3) obstacles affecting adherence 4) future improvements to the intervention 5) state of ncds in south africa. quotations to support the analysis are identified by a code, indicating their source respondent (rd). enjoyment of the intervention respondents identified fun and pleasure whilst being physically active as major motivators for continued adherence table 2. basic physiological changes over 12-week intervention period variables baseline (n = 10) postintervention (n = 10) p body mass index (kg/m2) 29.4 ± 8.5 29 ± 8.6 0.26 body fat (%) 34 ± 4 35 ± 4. 0.53 waist circumference (cm) 85.9 ± 15.4 80.8 ± 11.4 0.01** systolic blood pressure (mmhg) 117 ± 8 105 ± 37 0.31 diastolic blood pressure (mmhg) 76 ± 8 78 ± 10 0.49 resting heart rate (beats.min-1) 80 ± 16 77 ± 11 0.30 blood glucose (m.mol.l-1) 5.4 ± 0.9 5.3 ± 0.38 0.69 gpaq score (met-minutes/week) 689 ± 791 2760 ± 2523 0.03* 12-minute walk test (m) 1360 ± 353 1565 ± 220 0.01** sit-to-stand test (repetitions) 36 ± 6 43 ± 3 0.001** cd-risc score 73.8 ± 10.6 75 ± 8.2 0.66 values reported as mean ± sd * significant differences between baseline and post-intervention (p < 0.05); ** significant differences between baseline and post-intervention (p < 0.02) . table 1. general characteristics of participants variables value (n = 10) age (years) 33 ± 11.5 height (cm) body mass index (kg/m2) 162.3 ± 5.5 29.4 ± 8.5 income group* 5.3 ± 2.2 smokers (%) 40% medical aid members (%) 60% values reported as mean ± sd * income groups: 1 = no income; 2 = r1-r2499; 3 = r2500-r4999; 4 = r5000-r7499; 5 = r7500-r9999; 6 = r10 000-r15000; 7 = r15000 or more table 3. three-factor eating questionnaire changes over 12-week intervention period variables baseline (n = 10) postintervention (n = 10) p dietary restraint (score) 7.2 ± 5.2 9.9 ± 5.9 0.03* disinhibition (score) 7.6 ± 4 5.7 ± 3.1 0.15 hunger (score) 5.7 ± 4 4.5 ± 3.4 0.31 values reported as mean ± sd * significant differences between baseline and post-intervention (p < 0.05); original research sajsm vol. 29 2017 4 to the intervention. exercise sessions were light-hearted, with camaraderie between participants. variation in exercise drills ensured that participants were not partaking in monotonous activities. “i love exercising, so this was my main motivation. (rd1)” “i enjoyed the varied nature of workouts; i was never bored. (rd2)” group dynamics played an important role in the success of the intervention. participants enrolled as strangers but formed friendships during the intervention. the group setting allowed participants to work at their own pace whilst still being encouraged to challenge themselves. a family (mother and two daughters) was able to spend more time together as a result of participating in the intervention. “i felt encouraged, supported and motivated by other participants and so worked harder than i might otherwise have in a solo endeavour; like gym (rd2)” “i love exercising! my mom and my sister don’t. glad we found something that they would enjoy as well. (rd3)” “i felt the …… group dynamic, which i knew i would be more accountable for and to, were draw cards. (rd2)” respondents discussed the satisfaction they gained from challenging themselves. muscle aches in the days after training were not seen as negative but rather a sign that they had sufficiently worked the body and overcame perceptions of fatigue. “most people don’t enjoy the muscle pains after a good workout. i do. just like the saying goes, ’no pain, no gain!’ (rd3)” the intervention was considered convenient for participants. the times of training were well suited and coincided with some of the participants’ children’s soccer practices. “i couldn’t drop my son off [at soccer practice] and not attend a session! (rd4)” benefits of the intervention respondents mentioned the physiological changes brought about by an increase in physical activity. the changes discussed include an increase in fitness, muscle tone, decreased body mass, increased awareness of dietary intake and assistance with injuries. “i not only lost weight, but i gained muscle and became more fit. and eating unhealthy didn’t feel right anymore, so we just didn’t (rd4)” the structured, scientific focus of the intervention assisted participants in establishing safe exercise routines. the intervention also taught participants the value of becoming more responsible for their own health. “establishing the routine also helped me to become more accountable to myself by requiring me to proactively set up boundaries: my family and employer knew that on the days and during the time of training i was not available, which freed me up to concentrate on my fitness goals. (rd2)” “i learnt the correct way to do actual exercises to prevent injuries. (rd4)” the difficulties of exercise sessions were tailored to each individual. instructors were flexible in their exercise prescription, whilst providing encouragement or empathy when appropriate. “the positive feedback from trainers was also a plus there was always encouragement to work beyond perceived limitations but empathy when any of us were genuinely taking strain. (rd2)” obstacles affecting adherence the intervention was conducted throughout the cape town winter (cold and rainy months) and hence poor weather was an obstacle to participation. only one exercise session was officially cancelled due to heavy rain; however, cold and wet weather did affect adherence. “it was difficult to motivate myself to train when it was wet and rainy. (rd5)” family and work commitments reduced the time available to respondents to participate in the intervention. four of the five participants surveyed had children and four of the five were employed. “only difficulty with attending sessions was when they clashed with scheduled meetings at work. (rd5)” “i have a spouse and 4 kids. (rd4)” the state of non-communicable diseases (ncds) in south africa respondents from this study were generally aware of the negative impact that ncds such as obesity, diabetes and heart disease have on the country. a career-focused instead of a health-focused society that promotes the consumption of fast food was acknowledged. these societal influences, combined with modern technology that diminishes habitual physical activity levels, were seen to be one of the factors fuelling the rapid rise in ncds. “in my extended family we're constantly griping about how although we're relatively intelligent and enjoy successful careers, we can't shake off the weight and all of the lifestyle related diseases that are attendant to it. (rd2)” the study’s respondents no longer regarded access to equipment as a barrier to physical activity. the intervention was able to conduct a wide variety of exercise drills with minimal equipment. participants also identified that changing one’s lifestyle is not a solitary effort but that support from peers is crucial in modifying dietary and activity behaviours. “i was struck by how few resources we needed for the programme. we are socialised to believe that in the absence of contraptions and equipment we are unable to exercise. so the greatest benefit of having access to a biokineticist would be learning how to effectively and naturally get one's heart rate up and muscles working. (rd2)” “the fact that someone was actually waiting for me is what got me there (rd3)” poor education and low socio-economic status were mentioned as factors associated with the rise in ncds. it was perceived that many individuals in south africa have little knowledge about the importance of exercise or nutrition and their effect on health. with poor awareness of the problem at hand and insufficient income to make healthy lifestyle choices, it is likely the burden of ncds will continue to rise. “more focus needs to be placed on areas where knowledge and original research 5 sajsm vol. 29 2017 information about health, exercise and diet are not freely available. (rd3)” discussion quantitative the aim of this study was to (a) increase the physical activity levels of participants and (b) promote improved lifestyle choices, including healthy eating and stress reduction. over the duration of the 12-week intervention, the primary findings of the study were in the following physiological variables (p ≤ 0.05): an increase in the global physical activity questionnaire (gpaq) scores, self-reported eating restraints, 12-minute walks, sit-to-stand tests and a decrease in waist circumference. poor adherence and the resulting low sample size means no solid conclusions can be drawn from these results. it is also important to consider that a social desirability bias may have influenced the self-report measures. despite these limitations, these findings may, however, assist in generating hypotheses for future research. with the addition of two regular physical activity sessions per week, participants who were largely sedentary at baseline increased their physical activity levels (gpaq score) during the intervention. aerobic capacity and lower body muscular endurance, measured through the 12-minute walk and sit-tostand tests respectively, also significantly increased during the intervention. koster et al. 12] examined the association between waist circumference and mortality among 154 776 men and 90 757 women in the nih-aarp diet and health study. in comparison to participants with a normal bmi and waist circumference, those in the normal bmi group with a large waist circumference (men > 102 cm; women > 88 cm) had an approximately 20% higher mortality risk. this finding supports the fact that an elevated waist circumference is an independent risk factor for all-cause mortality. a statistically significant average decrease of five cm in participants’ waist circumference may confer health benefits and lower the risk of all-cause mortality. within this study, participants’ level of restraint regarding eating behaviours improved on the three-factor eating questionnaire. in a cross-sectional study of 529 middle-aged adults and 358 teenagers and young adults, cognitive restraint was positively associated in eating healthy food groups, such as green vegetables, and negatively associated with french fries (chips) and sugar.[10] therefore the increase in cognitive restraint observed over the course of the intervention may have resulted in improved dietary choices amongst participants. qualitative adherence the subjective experience of participants has been captured in the qualitative results section above. the following qualitative discussion will focus upon adherence, as it is a crucial component contributing to the success of a community-health intervention.[3] community-health interventions assist in promoting healthy behaviours; however, they are only effective if adhered to. modern environmental and personal circumstances often obstruct healthy lifestyle choices. determinants of adherence to a community-health intervention are complex. under the paradigm of the social ecological model, these determinants are a product of both personal and environmental characteristics.[5] personal characteristics personal characteristics include factors such as motivation, current health, desired appearance, enjoyment, social interaction, stress relief, challenge, skill development, achievement and personal satisfaction. respondents saw improvements in personal benefits from attending the exercise sessions. these subjective benefits included increased fitness, healthier eating habits and improved body composition. no personal characteristics were seen as barriers to participation as the participants surveyed had positive attitudes towards physical activity. this finding is supported by mccready and long [13] who found that participants with a more positive attitude toward exercising to reduce stress and tension, tended to have a higher attendance percentage. throughout the duration of the intervention, participants steadily progressed in the difficulty of the exercises performed, thus increasing their self-efficacy with regard to physical activity. previous research has demonstrated that with continued exercise participation, self-efficacy increases and adherence increases concurrently.[14] a prior history of physical activity is also beneficial as it positively influences physical activity behaviour during an intervention by promoting and shaping self-efficacy for exercise.[14] social environmental characteristics social environmental characteristics include factors such as demographics, work and family commitments, education and exercise group dynamics. behaviour change can only occur when both the individual and their social environment support that change. social support within a group exercise setting increases adherence to physical activity due to the ‘bonding’ experience of setting and reaching goals together.[14] for many of the participants, being part of a group was integral to their adherence and the camaraderie with fellow participants helped them maintain their physical activity levels. although time availability is a personal resource, lack of time is typically attributed to external factors.[15] family and work commitments are often prioritised over one’s own health, leading to reductions in physical activity. this is supported by white et al. [14] who demonstrated that becoming a parent is associated with reductions in physical activity for mothers. time availability was the greatest obstacle to adherence during this intervention. many participants prioritised other daily tasks over their participation. participants gained the most enjoyment from the social environmental characteristics of the intervention. these characteristics included the positive group dynamics, convenient location and time as well as the structured scientific approach. poor weather was the only environmental constraint mentioned in the surveys. in future interventions, this barrier can be addressed by acquiring the use of an indoor facility. reflexivity reflexivity refers to the recognition of the influence a researcher original research sajsm vol. 29 2017 6 brings to the research process. as researchers within the physical activity and public health fields, the investigator’s involvement in this study is unlikely to be bias-free. researchers actively conducted the 12-week intervention and developed friendships with participants. as the research team wanted the intervention to succeed, survey questions may have been framed in a more positive light. respondents offered little criticism about the intervention, likely to maintain social desirability. if an independent researcher had conducted the surveys, the results may have been different. participants saw the researchers as a source of knowledge to guide them on their journey of behaviour change with regard to physical activity and well-being. this dynamic made certain aspects of the survey process challenging as some of the respondents felt that they were ‘not qualified’ enough to answer the questions and criticise aspects of the intervention. the dynamic between researcher and participant did, however, contribute to the success of the intervention. the participants did not consider the researcher as superior to them and actively engaged with them on an individual basis. this type of attention is key to the success of a lifestyle intervention.[3] practical application to date, the profession of biokinetics has been confined to the private health sector. a major component of a biokineticist’s training involves using exercise modalities in the prevention and treatment of ncds, such as obesity, type 2 diabetes and heart disease. these skills are urgently required within the public health sector to slow the devastating impact of ncds on this country’s communities and economy. many biokineticists are denied internship positions due to the lack of capacity within the private health sector. the utilisation of both intern and qualified biokineticists in the public health sector provides a cost-effective approach to combat an increasingly sedentary south african lifestyle. the lifestyle intervention model used in this study is easily reproducible and demonstrates the potential for a wide array of positive effects on its participants; hence future research should expand upon this. study limitations it is important to note that this intervention was a pilot study, the main purpose of which was to facilitate future research. although the study demonstrated favourable results, the inferences that can be made with the small sample size, lack of a control group and predominately self-report measures are limited. the sweet hearts programme was organised and conducted by a single postgraduate student. no funding for the running costs of the intervention was received, which mirrors somewhat the lack of financial support and human capital available in combating the rise of ncds through physical activity and health education in south africa. the aim of the qualitative component of the study was to understand the social dynamics of the intervention, not generalisability. the researchers used a purposive sampling technique to recruit respondents, thus bias was introduced, as not all participants could be contacted and surveyed. the researchers acknowledge that their findings did not represent the views of participants who were not interviewed. social desirability may have also resulted in respondents favouring positive feedback whilst avoiding that which criticised the intervention. conclusion this pilot study examined the effect of a 12-week biokinetics primary prevention programme on health outcome measures. a total of 27 exercise sessions, combined with nutritional and healthy lifestyle advice, were conducted. the intervention experienced a high attrition rate with >50% of participants not presenting for post-intervention testing. despite this limitation and the small sample size (n = 10), the intervention showed significant improvements in health outcome measures amongst participants (p ≤ 0.05). these improvements included: an increased global physical activity questionnaire (gpaq) score, a 12-minute walk distance, sit-to-stand test repetitions, and a decrease in waist circumference. improvements were also noted in cognitive restraint with regards to eating behaviour. the qualitative surveys conducted (n = 5) offer valuable insight into the issue of adherence and how to improve the sweet hearts intervention. potential improvements include the use of an indoor venue, an increase from two to three sessions per week, inclusion of midway assessments, more detailed dietary guidance and greater diversity in the demographics of participants. the results of the sweet hearts intervention demonstrate the difficulty and importance of maintaining adherence to a community health intervention programme. the favourable results of the small sample size demonstrate the potential benefit of biokinetics-based programmes in the public health sector; and provide proof of concept for the dedication of resources towards health promotion within a community setting. acknowledgements: scholarships for the postgraduate student who conducted this study were received from the university of cape town (uct) and the national research foundation (nrf). the authors wish to thank the biokinetic humanitarian project (bhp), victoria hospital wynberg, tramway football club, and biokineticists devon coetzee, samantha jones and megan grobler for their assistance in conducting this project. references 1. bradshaw d, norman r, pieterse d, et al. estimating the burden of disease attributable to diabetes in south africa in 2000. s afr med j 2007;97 (8pt2): 700-706. 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[pmid: 24893527] 8. american college of sports medicine. acsm’s guidelines for exercise testing and prescription, 7th ed, baltimore, md: lippincott williams & wilkins, 2006. 9. noorbhai mh. a public health approach to increase physical activity and health education : the biokinetic humanitarian project. afr j phys heal educ recreat danc 2013;19:993–998. 10. de lauzon b, romon m, deschamps v, et al. the three-factor eating questionnaire-r18 is able to distinguish among different eating patterns in a general population. j nutr 2004;134:2372–2380. [pmid:15333731] 11. cooper kh. a means of assessing maximal oxygen intake: corrolation between field and treadmill testing. jama 1968;203(3):201-204. [pmid: 5694044] 12. koster a, leitzmann mf, schatzkin a, et al. waist circumference and mortality. am j epidemiol 2008;167:1465– 1475. [.doi:10.1093/aje/kwn079] 13. mccready ml, long bc. locus of control, attitudes toward physical activity , and exercise adherence. j sport psychol 1985;7:346–359. [https:// doi.org/10.1123/jsp.7.4.346] 14. white jl, ransdell lb, vener j, et al. factors related to physical activity adherence in women: review and suggestions for future research. women health 2005;41:123–148. [doi:10.1300/j013v41n04 07] 15. cobb-clark da, kassenboehmer sc, schurer s. healthy habits: the connection between diet, exercise, and locus of control. j econ behav organ 2014;98:1–28. [doi.org/10. 1016/j.jebo.2013.10.011] 16. thomas sg, goodman jm, burr jf. evidence-based risk assessment and recommendations for physical activity clearance: established cardiovascular disease. appl physiol nutr metab 2011;36:s190–213. [doi: 10.1139/h11-050] commercial companies in the health and fitness industry often misuse ‘science’ in an attempt to gain credibility so that they can sell more products and make more money. a product supported by ‘science’ creates the impression that it is a worthy product. as laypeople are generally poorly educated on the role of science in health and fitness, they are often influenced by the many adverts that take advantage of this. for example, some companies market their products using terms such as ‘doctors agree …, experts have shown…’, or have adverts with pictures of learned-looking people wearing white lab coats next to their product. other marketing material proudly claims that the product ‘...has been tested at a south african university’. while this statement may be true it lacks any sense with regard to supporting the efficacy of the product. one can do an experiment on the ergogenic effects of a piece of coal and honestly claim that it has been ‘tested’, even if it has absolutely no positive ergogenic effect. proving efficacy, validity, repeatability and potential side-effects of a product is another matter entirely. these are characteristics that have to be identified before legitimate claims can be made, and it may take several years of experimentation to accumulate the knowledge. strategies for misusing ‘science’, such as those outlined above, are successful in south africa largely because of the stance of the advertising standards authority (asa) which seems to prioritise legal matters over scientific facts and is too easily influenced by pseudo-science. 1 this has made ‘south africa a great place for pedlars of snake-oils, slimming aids and unproved “therapies”’. 1 the first step in changing this paradigm is to educate the public on the role of science in developing knowledge. the scientific process begins with research that attempts to answer a question. in sports medicine the question is often identified by the coach, trainer or players. sometimes physiotherapists formulate a question and sometimes a doctor identifies a relevant question for which there is no immediate answer. the point is that it does not matter where the question originates. a good research study is one that has a clearly identified question that is relevant. ernest rutherford, a pioneering nuclear physicist who won the nobel prize for his work has been quoted as saying ‘a theory that you can’t explain to a bartender is probably no damn good’ (quoted in francis collins, the language of god, 2006:60). this same logic can be applied to simplifying questions around which research studies are designed. a clear, relevant question initiates a process of designing a study that attempts to answer the question. factors such as type of subjects, adequate control, and sample size to make the data interpretable and representative have to be considered. well-designed studies that consider these points have a high ‘believability’ factor and contribute towards providing an answer to the question around which the study was designed. the process does not end there. after implementing the study plan the researchers still have to prepare the manuscript and subject it to peer review in an attempt to get it published. this is not an easy task. most of the top international journals have rejection rates of around 70%. in an analysis of research papers published in 6 leading basic science journals (approximately 25 000 papers), only 2% of the studies contained some information that had the potential to make a significant contribution to clinical application. 2 the rate of transfer of knowledge from research into practice is low. this can be illustrated in the acquisition of the practical knowledge on carbohydrate ingestion during exercise. in the last 30 years 1 103 studies have investigated carbohydrate ingestion and exercise (accessed from pubmed using the keywords ‘carbohydrate’, ‘ingestion’ and ‘exercise’). the collective knowledge from all these studies can be reduced to about 10 practical points. there are many other examples of routine practices in sports medicine which have evolved from systematic research. the following are thanked for reviewing manuscripts submitted to the sajsm during 2006. all these reviewers have made a significant contribution to the peer-review process which is the core to developing knowledge. this is the first of 4 issues of the sajsm for 2007. i trust that you will enjoy reading it and that the papers published in this issue will contribute in some way to the promotion of sports medicine in an evidence-based way! mike lambert editor-in-chief 1. welz m, ed. fat chancers. noseweek 2007; 89: 18-21. 2. bishop db, burnett a, farrow d, gabbett, t, newton, r. sport science roundtable: does sports-science research influence practice? international journal of physiology and performance 2006; 1(2): 161-8. the misuse of science a topic which is receiving much publicity as i write is the banning of 5 skinny models from participating in the madrid fashion week. madrid’s regional government imposed the rules ‘to protect the models as well as teenagers who may develop anorexia as they try to copy underweight catwalk stars’. 1 they used a body mass index of 18 as their cutoff value. the ‘anti-thin’ move has been criticised in paris and new york, two of the world’s leading fashion centres. however, in italy the move was supported by the mayor who intimated that she would like to apply the same rulings when the fashion show moves to milan. the motive for imposing the ban is noble, as the ‘skinny trend’ is not showing signs of abating. a recent report by the british medical association identifies a link between the images of ‘abnormally thin’ models that dominate television and magazines, and the increase in cases of anorexia nervosa and bulimia. 2 the incidence of anorexia is at an all-time high with predictions of 0 5% of all females having eating disorders. while eating disorders were previously usually regarded as a female syndrome, the situation is changing with a steady increase in the number of men being diagnosed with eating disorders. a recent estimate predicts that of the 60 000 people with eating disorders in the uk, 10% are male. 2 this trend can most likely be explained by the contemporary lean, hungry look of male stars. to get a snapshot view of changing body beautiful images of different eras one only has to compare the ‘hunks’ of the 1960’s movies (i.e. sean connery as james bond) to modern day hunks to see how the masculine image has changed. marilyn monroe, with her curvy body shape in the 1950s would probably be regarded as too fat for a leading role 50 years later. while the organisers of the fashion shows should be complimented for taking a bold stand against their skinny, unhealthy-looking models, they can be criticised for the way in which they have gone about it. using a body mass index of 18 as a cut-off value is inappropriate and may penalise some models who live normal healthy lives. instead of this approach the organisers should establish a structure that evaluates the health status of the models including their eating, sleeping and substance abuse habits and make decisions accordingly. the information on how to do this is available; it just needs to be applied. this third issue of the journal for 2006 has 4 interesting papers. the first paper by professor mars and colleagues examines the cooling of skin, subcutaneous fat and muscle with an icepack, at rest and after short-duration exhaustive exercise. this study produced some interesting results with important clinical applications. the next paper by ian cook examines the accuracy of different types of pedometers. it is well known that people who use pedometers are encouraged to be more physically active, so therefore there is great value in making pedometers available to the general public. however, the enthusiasm to make and distribute pedometers has exceeded the concern about their accuracy. this study addresses this point with a comprehensive research design. the results make a valuable contribution to the literature. the third paper, by dr mchardy and colleagues from macquarie injury management group, macquarie university, sydney, australia, is a clinician’s perspective of the modern and classic golf swing. this paper is relevant to sports physicians, biokineticists and physiotherapists and provides a clear analysis of the different types of golf swing and their possible link to injury, particularly lower back pain. finally the paper by dr draper and her colleagues describes the state of the fitness industry in south africa. this comprehensive study gathered data from 442 facilities around the country. the data provide an important benchmark for the state of the industry and will make a significant contribution to the development of perceived weaknesses in the industry. mike lambert editor-in-chief 1. milan fashionistas fear spanish skinny model ban. news.yahoo.com/s/ nm/20060914/od_nm/italy_models_dc (accessed 18 september 2006) 2. the changing shape of the model. news.bbc.co.uk/1/hi/uk/769460.stm (accessed 18 september 2006) skinny fashion – a role for sports medicine? sajsm vol 18 no. 3 2006 57 editorial pg57.indd 57 9/21/06 12:15:22 pm sajsm vol 19 no. 1 2007 1 editorial aginsky k de beer j de milander l de villiers r dugas j durandt j gay j gray a havemann l johnston r keet j kohler r lambert v manjra s mckune a meurer b micklesfield l potter p raine r reid s saunders c smith c smith j stretch r swart j viljoen w wright z pg1.indd 1 4/4/07 9:52:46 am original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license limb length discrepancy and gait parameters of amateur football players in lagos state, nigeria a k akodu, phd; o a akindele, bsc department of physiotherapy, college of medicine, university of lagos, nigeria corresponding author: a k akodu (aakodu@unilag.edu.ng) playing football rigorously while growing up may lead to the appearance and development of a real limb length discrepancy (lld). [1]more precisely, the observations designate that growth is slower in the lower limb used to kick the ball and may lead to lld. the weight of the ball and an intensive careful play regimen may be aggravating factors.[1] abnormalities in gait pattern can be a consequence of limb length discrepancy of two cm or more, resulting in an increase in muscle activity, heart rate and oxygen consumption.[2]disparity in limb length is usually connected to the development of gait abnormalities which can result in degenerative arthritis of the lower extremity and lumbar spine.[3] a gait cycle can be defined as a time interval between the heel strike of an extremity and when the same heel contacts the ground again.[4]during locomotion, the gait cycle of a healthy individual is high but the gait of an unhealthy individual displays deviation from its normal cycle.[5] the more time a person spends training, the more probable their gait will be less periodic and less harmonic.[6] this can be explained by the fact that training beyond a critical level could lead to musculoskeletal reconstruction that has not been recognised by the locomotor centres in the neural network, resulting in a gait that is less well-controlled.[6] amateur football is a compound sport and its performance is based on physical, physiological and psychological aspects. due to the paucity of data on limb length discrepancy and gait parameters of amateur football players in the environment, this study was conducted to determine the correlation between the aforementioned variables in amateur football players in lagos state, nigeria. methods this cross-sectional survey was carried out between may and october 2019. the study involved 89 amateur football players recruited from six football teams in different stadia in lagos state and used a non-probability sampling technique (purposive sampling technique).this sampling technique also used in the study of sajjan,[7] was adopted because of the small sample that exists among the registered amateur football clubs involved in this study. only registered amateur football players were included in the study. the football players who had stopped playing football but who participated in other sports and had a previous or current sport injury were excluded. before conducting this research, written permission was obtained from the health research and ethics committee of the college of medicine at the university of lagos (approval number: cmul/hrec/06/19/551). the reason for the study was clearly explained to the participants. they were also assured of the privacy of their responses. each participant gave written informed consent before the start of the study. assessment of limb length discrepancy the tape measurement method (tmm) was used for measuring limb length discrepancy. this was undertaken using two examiners and had an intraclass correlation coefficient (icc) of 0.922 and 0.990 with an excellent intra-rater agreement of 0.990 and 0.985 respectively. [8] the pelvis was aligned against the back of the plinth, and the distance between the medial malleoli of each tibia was measured.[1] using a tape measure, the researcher assessed the distance between the anterior superior iliac spine to the medial malleolus (real length) of the leg and from the umbilicus to the lateral malleolus (apparent length) of the leg. a comparison of both sides was done.[9] a limb length discrepancy (lld) of 1.1 cm and above was classified as abnormal. assessment of gait parameters gait parameters were measured by covering a 10 m walkway with white cardboard. participants placed both feet in a tray of talcum powder. they were then instructed to walk normally along the pathway, starting with the right foot. the researcher advised the participants to look ahead and continue the same walking pace until the end of the cardboard [10]. an assessment of distance parameters (step and stride length) was done with a metal ruler and recorded in centimetres. the step length was assessed as a line at right angles to the heel’s reference points and its intersection with the ipsilateral line of progression. stride length was assessed as the spatial distance between the heel’s reference points of one foot on the ipsilateral background: football is a widely played sport globally. limb length discrepancies have been found to be common among football players and these may lead to abnormal gait. objectives: the purpose of this study was to determine the relationship between limb length discrepancy (lld) and gait parameters of amateur football players in lagos state, nigeria. methods: eighty-nine amateur football players participated in the cross-sectional study. they were recruited from different stadia in lagos state. limb length and gait parameters were measured using tape and footprint measurements. results: the prevalence of real limb length discrepancy among the participants was 75% (n = 67). the results of this study showed that the right leg was the shorter leg in 60% (n = 53) of the participants. there was no significant correlation between gait parameters and limb length measurement. conclusion: although limb length discrepancy is common among amateur football players in lagos state, the relationship between limb length and gait parameters is weak. keywords: athletes, real leg length, step length, spatial distance s afr j sports med 2020;32:1-3. doi: 10.17159/2078-516x/2020/v32i1a8029 mailto:aakodu@unilag.edu.ng http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8029 https://orcid.org/0000-0003-0262-6376 https://orcid.org/0000-0002-0968-5929 original research sajsm vol. 32 no. 1 2020 2 side. the base of the gait was measured as the spatial distance between the heel’s reference points and the opposite ipsilateral line of progression measured in centimetres [1]. the gait was assessed by only one examiner. however, other examiners found the technique to be reliable, as evidenced by pearson's r correlation coefficients ranging from 0.92 to a perfect correlation of 1.00 [11]. statistical analysis the data were analysed using ibm spss (statistics for windows, version 25.0. armonk, ny: ibm corp) and summarised using the descriptive statistics of mean, standard deviation, frequency and percentage. pearson’s correlation for parametric variables was used to determine correlation between lld and gait parameters. the authors accepted an alpha level of 0.05. results the participants were between the ages of 14 and 31 years, with a mean age of 22 ± 3 years. the mean body mass index (bmi) of the participants was 21.5 ± 1.5 kg/m2 (table1). the mean values of the right real limb length and left apparent limb length were 96.5 ± 4.0 cm, and 102.3 ± 8.4cm respectively (table 2). twenty-five percent of the participants (n = 22) had normal limb length. in 41% of the participants (n =36) the right leg was longer than the left leg (table 2). the mean of the step length, stride length and the base of support of the participants was 36.3 ± 10.9 cm, 84.4 ± 18.8 cm and 15.6 ± 6.6 cm respectively (table 2). the correlation between limb length measurement and the physical properties of the participants are shown in table 3. there was a significant but weak positive correlation (r =0.23, p=0.03) between age and right real limb length. all limb length measurements had a significant positive correlation with height. there was a significant moderate positive correlation between height and right real limb length(r = 0.41, p=0.001) and height and apparent limb length (r = 0.51, p=0.001) (table 3). there was a significant moderate positive correlation between weight and real limb length measurement (right) (r = 0.41, p=0.001). there were no significant correlations of any of the limb length measurements and gait parameters (table 4). discussion this study was undertaken because the literature on the leg length discrepancy and gait in amateur football players is sparse. the authors have shown that 75% of the participants had limb length discrepancies, with 59% having a shorter right leg. the shorter limb is often the kicking leg [1]. the walking pattern of athletes was no different to that of non-athletes, as seen in subjects used in the study by leroy et al.[12]. however, there may be differences depending on the sport played. .for example, the step length has been found to vary among football players, and playing football indicates differences in the table 1. physical characteristics of the participants (n=89) characteristic frequency (n) percentage (%) age groups (years) <20 24 27 21-25 58 65 26-30 5 6 31-35 2 2 mean 22 ± 3 height (m) 1.40-1.50 1 1 1.51-1.60 2 2 1.61-1.70 20 23 1.71-1.80 66 74 mean 1.74 ± 0.06 weight (kg) 51-55 3 3 56-60 10 11 61-65 30 34 66-70 37 42 71-75 9 10 mean 65.2 ± 1.5 body mass index (kg/𝐦𝟐) under 18.50 1 1 18.50-24.90 86 97 25.00 – 29.90 2 2 mean 21.5 ± 1.5 data are expressed as a frequency of the total participants per characteristic. where applicable data are expressed as mean ± sd. body mass index (bmi) range; underweight (< 18.5 kg/m2), normal weight (18.5 to 24.9 kg/m2), overweight (25.0 to 29.9 kg/m2). table 2. gait parameters and limb length measurement of the participants (n= 89) variables mean ± sd frequency (n) percentage (%) gait parameters step length (cm) 36.3 ± 10.9 stride length (cm) 84.4 ± 18.8 base of support (cm) 15.6 ± 6.6 limb length measurements real limb length right (cm) 96.5 ± 4.0 real limb length left (cm) 97.5 ± 6.6 normal real limb length difference 22 25 abnormal real limb length difference 67 75 apparent limb length right (cm) 100.9 ± 4.3 apparent limb length left (cm) 102.3 ± 8.4 normal apparent limb length difference 15 17 abnormal apparent limb length difference 74 83 longer limb right leg 36 41 left leg 53 59 data are expressed as a frequency of the total participants per variable group or expressed as mean ± sd. an apparent or real limb length difference of < 1.1 cm was classified as normal; a difference ≥ 1.1 cm was classified as abnormal. original research 3 sajsm vol. 32 no. 1 2020 locomotion pattern between the right and left lower limbs.[12]this study has confirmed this since there was no relationship between the limb length and gait parameters. a previous study showed that playing football intensively before or during the period of growth may encourage the appearance of a real limb length discrepancy. [1] more precisely, growth is slowed in the lower limb used to kick the football which may lead to a leg length discrepancy of up to 17 mm.[1]among players who began their football career before the age of 13 years, 96% had the kicking leg as the shorter limb. this pattern was observed in only 53% of the players who started playing football later. [1] conclusion based on the results of this study, it can be concluded that there was high prevalence of the real limb length discrepancy among the participants. it is recommended that amateur football players with limb length discrepancy should be encouraged to train specifically and use proper footwear to prevent poor gait parameters. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. acknowledgements: the authors appreciate the involvement of the participants in this study. author contributions: conceptualisation, aa; methodology, aa; investigation, oa; writingoriginal draft, aa; writing-review and editing, aa; resources, all authors; supervision, aa. references 1. guer j-l, blanchard s, harnagea mc, et al. does intensive soccer playing during the growth period lead to leg length discrepancies? sports med int open 2017; 1(5): e183–e187 [doi:10.1055/s-0043-117600] [pmid: 30539105] 2. thakral r, johnson aj, specht sc, et al. limb-length discrepancy after total hip arthroplasty: novel treatment and proposed algorithm for care. orthopedics 2014; 37(2): 101-106.[doi: 10.3928/01477447-20140124-06][pmid: 24679191] 3. moseley cf. leg length discrepancy. in: morrissy rt, weinstein sl, eds. lovell and winter’s pediatric orthopedics. 6th ed. philadelphia, pa: lippincott williams & wilkins 2006: 1213-1256 4. kharb a, saini v, jain yk, et al. a review of gait cycle and its parameters. ijcem 2011; 13: 2230-7893 5. crane bt, demer jl. effects of vestibular and cerebellar deficits on gaze and torso stability during ambulation. otolaryngol head neck surg 2000; 123 (1 pt 1): 22-29. [doi:.10.1067/mhn.2000.105923] [pmid: 10889475] 6. tsivgoulis sd, pajagelopoulos pj, efstathopoulos n, et al. accelerometry for evaluation of gait pattern in healthy soccer athletes. int j med res 2009; 37: 1672-1700. [doi:. 10.1177/147323000903700604] 7. sajjan m. mental toughness among athletes: a comparative study. ijar 2018; 6(2): 157-161 8. neelly k, wallmann hw, backus cj. validity of measuring leg length with a tape measure compared to a computed tomography scan. physiother theory pract. 2013; 29(6): 487492. [doi:10.3109/09593985.2012.755589][pmid: 232899961] 9. clark cr, herbert hd, schoch ep, et al. leg-length discrepancy after total hip arthroplasty. j am acad orthop surg 2006; 14(1): 38-45. [doi: 10.5435/00124635-200601000000007][pmid: 16394166] 10. wilkinson mj, menz hb. the measurement of gait parameters from footprints. the foot 1997; 7(1):19-23 [doi: 10.1016/s09582592(97)90005-5] 11. taranto j, taranto mj, bryant a, et al. angle of gait: a comparative reliability study using footprints and the emedsf. the foot 2005; 15(1): 7-13. [doi: 10.1016/j.foot. 2004.05.002] 12. leroy d, polin d, tourny-chollet c, et al. spatial and temporal gait variable differences between basketball, swimming and soccer players. int j sports med 2000; 21(3): 158-162. [doi.org/10.1055/s-2000-9467][pmid: 10834345] table 3. correlation between limb length measurement and anthropometric variables of the participants (n=89) real length right real length left apparent length right apparent length left age (years) r 0.23 -0.06 0.08 -0.07 95% ci 0.02 to 0.42 -0.15 to 0.26 -0.13 to 0.28 -1.14 to 0.27 p value 0.03* 0.58 0.48 0.52 height (m) r 0.41 0.22 0.51 0.23 95% ci 0.22 to 0.57 0.01 to 0.41 0.34 to 0.65 0.02 to 0.42 p value 0.001* 0.04* 0.001* 0.03* weight (kg) r 0.41 0.26 0.37 0.17 95% ci 0.22 to 0.57 0.05 to 0.44 0.18 to 0.54 -0.04 to 0.37 p value 0.001* 0.01* 0.001* 0.12 bmi (kg/𝐦𝟐) r 0.01 0.05 -0.14 -0.06 95% ci -0.20 to 0.22 -0.16 to 0.26 -0.07 to 0.34 -0.15 to 0.26 p value 0.91 0.63 0.18 0.56 * significant at p<0.05. r, pearson correlation coefficient; ci, confidence interval; bmi, body mass index table 4. correlation between limb length measurement and gait parameters of the participants (n=89) real length right real length left apparent length right apparent length left step length (cm) r -0.09 -0.14 0.06 -0.07 95% ci -0.29 to 0.12 -0.34 to 0.07 -0.15 to 0.26 -0.27 to 0.14 p value 0.38 0.20 0.60 0.51 stride length (cm) r 0.05 -0.08 0.02 0.04 95% ci -0.16 to 0.26 -0.28 to 0.13 -0.19 to 0.23 -0.17 to 0.25 p value 0.65 0.49 0.85 0.73 base of support (cm) r -0.11 -0.15 -0.07 -0.03 95% ci -0.31 to 0.10 -0.35 to 0.06 -0.27 to 0.14 -0.24 to 0.18 p value 0.32 0.15 0.54 0.78 r, pearson correlation coefficient; ci, confidence interval file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1055/s-0043-117600 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.3928/01477447-20140124-06 doi:.10.1067/mhn.2000.105923 file:///c:/users/yvonne/downloads/%5bdoi:.%2010.1177/147323000903700604 doi:10.3109/09593985.2012.755589 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1016/s0958-2592(97)90005-5 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1016/s0958-2592(97)90005-5 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi.org/10.1055/s-2000-9467 sajsm 595 (commentarty).indd position statement 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license implications of covid-19 for resumption of sport in south africa: a south african sports medicine association (sasma) position statement – part 1 da ramagole,1 mbchb, msc; dc janse van rensburg,1,2 mmed, md; l pillay,1 mbchb, msc; p viviers,3,4,5 mbchb, mmedsc; p zondi,6,7 mbchb, msc, j patricios,8 mbbch, mmedsci 1 section sports medicine & sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa 2 medical board member, international netball federation, manchester, uk 3 campus health service, stellenbosch university, south africa 4 institute of sport and exercise medicine, division of orthopaedic surgery, department of surgical sciences, faculty of medicine and health sciences, stellenbosch university, south africa 5 fifa medical centre of excellence, south africa 6 sports science institute of south africa, newlands, south africa 7 south african sports confederation and olympic committee, medical advisory committee 8 wits institute for sport and health (wish), faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: da ramagole (maki.ramagole@up.ac.za) south africa, like many other countries, is grappling with the various implications of the coronavirus disease 2019 (covid-19) pandemic. the pandemic has had a significant effect on individuals, businesses, and society at large. sport was not spared from the impact with the cessation of all professional and non-professional sport. all recreational parks and fitness centres were closed. south africans participating in many codes of amateur and elite sport had scheduled events cancelled or postponed and their ability to train was limited. government imposed a lockdown period to control and slow down the spread of infection, strongly advocating for preventative measures, including physical distancing and hand sanitising, emphasising that no specific treatment or vaccine is available. the initial ‘hard’ level 5 lockdown was supposed to be for three weeks, but was subsequently increased by two more weeks to further contain the spread of the virus and to give the relevant authorities time to coordinate a national and subnational response. a risk-adjusted approach was thereafter adopted, implementing various levels of societal reintegration to progressively return the country to normality while trying to mitigate the spread of disease. carmody et al., describe similar periods of lockdown and what these measures aim to achieve when facing a novel pathogen and pandemic for which most were unprepared.[1] the south african sports medicine association (sasma) has written a position statement on guidelines for the safe return to sports for athletes, based on literature from experts in various fields. this is intended as a guide, and should be used in conjunction with medical practitioners’ clinical evaluation of athletes and local government guidelines. reducing transmission globally, governments have restricted activities to minimise human-to-human transmission of the virus. this activity restriction is aimed at buying time and allowing for international collaboration between governments and local authorities while strategising to allocate medical resources to counter the pandemic. in this period three pillars of the strategy have been identified, namely.[1] 1. testing: suspected cases should be tested where possible, but this has to be done where it is clinically appropriate and preventative strategies should be in place. [1] 2. contact tracing: measures should be in place to follow-up on all confirmed cases of covid-19 and all contacts traced to identify and stop transmission. [1] 3. treatment: all cases should be managed effectively, and governments should be equipped to provide adequate numbers of hospital beds, intensive care unit (icu) capacity, ventilators and healthcare professionals. [1] organised events five key questions address risk factors when allowing organised events. these are highlighted by the world health organisation (who) and have been incorporated into a risk assessment tool developed to guide event organisers in mitigating the spread of covid-19.[2] the questions are as the significant impact of the coronavirus disease 2019 (covid19) pandemic has extended to sport with the cessation of nearly all professional and non-professional events globally. recreational parks and fitness centres have also closed. a challenge remains to get athletes back to participation in the safest way, balancing the protection of their health while curbing the societal transmission of the virus. with this position statement, the south african sports medicine association (sasma) aims to guide return-to-sport as safely as possible, in an evidence-based manner, given that covid-19 is a new illness and new information from experts in various fields continues to emerge. clinical considerations are briefly described, focusing on a return-to-sport strategy, including education, preparation of the environment, risk stratification of sports and participants, and the practical implementation of these guidelines. the management of the potentially exposed or infected athlete is further highlighted. it is important that persons charged with managing athletes’ return-to-sport in any environment must be up-to-date with local and international trends, transmission rates, regulations and sport-specific rule changes that might develop as sport resumes. additionally, such information should be applied in a sports-specific manner, considering individual athlete’s and team needs and be consistent with national legislation. keywords: return to play, coronavirus, pandemic s afr j sports med 2020; 32:1-6. doi: 10.17159/2078-516x/2020/v32i1a8454 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8454 https://orcid.org/0000-0001-6682-3438 https://orcid.org/0000-0002-5341-6080 https://orcid.org/0000-0002-8353-3376 https://orcid.org/0000-0003-1058-6992 https://orcid.org/0000-0002-6829-4098 https://orcid.org/0000-0001-6001-5966 position statement sajsm vol. 32 no. 1 2020 2 follows:  is there documented active local transmission of covid19 (community spread) in the country that will be hosting the events?  are there multiple venues, cities or countries hosting the event, or is it held in a single venue?  are the participants and spectators also from other international destinations? do those countries have documented local transmission of covid-19 which is still active i.e. documented community spread?  are most of the participants or spectators expected to be high-risk for becoming infected and developing severe covid-19 disease? this category includes people over 65 years of age or people with underlying chronic medical conditions.  does the event involve contact or non-contact sports (where contact sports are considered a higher risk for transmission of covid-19)? one method of mass gathering risk stratification is colour coding, as proposed by carmody et al[1] (table1). clinical considerations the clinical presentation of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) differs in individuals, ranging from mild to severe.[3] cardiorespiratory complications respiratory system illnesses are a major characteristic of the disease and in athletes it may result in a significant loss of training time, so requires special mention. [4] there is also an increased risk of cardiac complications in patients with a history of viral infection.[5] persons with influenza infections have a higher incidence of cardiovascular complications, like myocarditis, heart failure and acute myocardial infarction, in comparison to non-infected individuals.[6] athletes who have had a febrile viral infection, including sars-cov-2, are at risk of developing cardiovascular complications, as shown by elevated troponin levels in affected individuals. [7] athletes should avoid competitive sports for three to six months if they sustain a myocarditis,[4] and a risk stratified return-to-sport paradigm should be implemented.[6] guidance on return to sport for these athletes should include a cardiology review supported by an ecg, echocardiogram, and a slow gradual retraining and return to sports programme.[7] this gradual retraining and loading is also necessary for the prevention of injuries and acute illnesses, and to maintain the psychological wellbeing of athletes.[8] mental health this “cool off” period will negatively affect the recreational and professional athlete’s level of conditioning and ability to qualify and compete. forced training restriction is also associated with alterations in mood and feelings of depression in athletes, and has been described in approximately 50% of athletes during south africa’s lockdown. [9] mental fatigue due to the lockdown will thus need to be addressed to help them deal with this pandemic and the consequences of training restrictions.[10] exercise and immune function it has been widely publicised that exercise helps to improve the immune system and that during lockdown exercise should be continued as advised by the who, but the greatest responsibility is to limit the exposure to and spread of covid 19.[11] it is recognised that moderate levels of activity are required to assist in improving immunity, and that people who are physically active are likely to have a less severe form of illness and may recover earlier than those who are less active. [11] athletes should be cautioned to avoid marked changes in load table 1. risk stratification guide copyright approval from bjsm and carmody et al.[1] position statement 3 sajsm vol. 32 no. 1 2020 and high-intensity bouts of exercise as this may reduce immunity. these high-intensity activities are described as ‘activities performed by highly athletic individuals’. [11] in addition, with the approaching winter in south africa, it is advisable to have a flu vaccine. this does not protect against covid-19 but may reduce the burden of illness during the vulnerable winter months.[12] body composition and diet although many athletes may continue to exercise under lockdown (64%),[9] a change in training habits and reduction in training load may have resulted in changes in body composition. there is a concern that athletes will have deconditioned and may succumb to injuries should they return to full activity prematurely or in an uncontrolled manner. dietary habits and nutrition may also be impacted negatively.[9] the importance of balanced nutrition, good hydration, adequate vitamin d and continuing to exercise under lockdown has been emphasised.[10] considering all of the aforementioned factors, a return -tosports strategy has to be structured safely and plans should include a staged increase in exercise levels. return-to-sport several international and south african associations have presented plans on restarting competitive sport postlockdown. these include specific clinical work-ups for the participating athletes.[7,13] both the athletes and administrators need to be aware of how to return to sport as safely as possible. the who has published a guideline ‘mass gathering mitigation checklist for covid-19: addendum for sporting events’ with a checklist of measures that have been implemented to reduce the risk of transmission. [2] based on the scoring system of 0 to 6, where 0 is a negligible risk, and 6 is a very high risk, event organisers can then classify the risk level, formulate a risk-appropriate return-to-play strategy, and gauge their preparedness. this complete risk evaluation can be found in the separate supplementary document. the australian institute of sports released a detailed white paper on exercise loading after reduced exercise which can be used as a guide to protect against injuries. this paper recommends that the length of reduced exercise and the percentage of exercise reduction should be used to determine the period it will need to return to the previous level of conditioning.[14] the south african sports confederation and olympic committee (sascoc) released a media statement wherein they stated that they cannot dictate to federations how to phase in their return-to-sport strategies. instead, they advised that each federation’s medical team, in conjunction with other medical authorities, should make use of all available knowledge and resources to formulate a sport-specific plan on how to safely resume sporting activities.[15] in compliance with the government’s risk-adjusted strategy to reduce coronavirus transmission risk and address the need for a phased return-to-sport, a stepwise return to normality has been recommended.[1] these levels of alert have also been adopted by the wits institute of sport (wish) on risk assessment and return-to-sport[16] (table 2). as the risk-adjusted levels become more lenient, the ideal is to achieve a return-to-sport participation whilst protecting athletes and others from infection. it is important to note that all guidelines should be in tandem with government protocols presented by the national institute of communicable diseases table 2. alert levels on risk assessment and return-to-sport alert level environment modifications examples 5 exercise in home environment only no use of public gyms exercise alone exercise with asymptomatic family members only stretch and strengthen routines · yoga, pilates · home-based online classes · home treadmill, stationary cycle and rower 4 exercise in suburbs, open spaces and nearby sports fields no group exercising · increase social distancing to at least six metres · strict hygiene practices (nose-blowing, coughing, spitting) · exercise alongside each other or staggered instead of behind each other jogging, cycling, multiple sprints · individual sports-specific skills training · single tennis games 3 exercise at training grounds avoid public transport to and from training and wear a cloth mask when travelling · no team travel · coaching and support staff to wear cloth masks · disinfecting equipment before and after use · no on-site team or group meetings · maintain social distancing at six metres minimum for all exercises · exercise alongside or staggered to each other instead of behind each other · no sharing of water bottles · shower at home · no spectators at training sport-specific fitness · sports-specific skills training with limited equipment e.g. soccer and hockey drills, netball/basketball skills, cricket batting and bowling 2 exercise at training grounds with full equipment train in small groups (maximum five at a time maintaining two metres social distancing during sessions) · no team meetings · shower at home · no spectators non-contact soccer and rugby drills · hockey, netball and basketball team drills · squash games 1 full training and competition limit team meetings · no spectators matches and games · no spectators adapted from and copyright granted by bjsm and carmody et al.[1] position statement sajsm vol. 32 no. 1 2020 4 (nicd) and the department of health (doh). sasma guidelines the south african sports medicine association (sasma) recommends that, as a minimum, the following be incorporated into any post-covid-19 return-to-sport strategy: 1. education 2. preparing the environment 3. risk stratifying the sport 4. risk stratifying the participants 5. practical implementation of mitigating measures of different sports 1. education  ensuring that there is continuous education of athletes and staff regarding physical distancing, hand hygiene, respiratory etiquette and mask-wearing.  displaying posters around training areas and change rooms reminding everyone about the aforementioned issues.  forbidding team handshakes or contact celebrations.  appointing a health officer to ensure compliance with all these aspects.  educating athletes regarding temporary rule changes that may be adopted by sporting bodies, both local and international (e.g. no spitting on fields or not using saliva to shine cricket balls). 2. preparing the environment  ensuring that there is sufficient access to “non-touch” soap dispensing and running water as a minimum. alternatively, 70% alcohol-based sanitiser must be provided.  cleaning thoroughly and regularly with appropriate products of all contact surfaces (0.5% sodium hypochlorite) before and after sports participation.  ensuring closed areas are ventilated, physical distancing (at least two meters) of an athlete not participating is enforced and face masks are worn (e.g. change rooms during halftime).  washing of kit by the player themselves as per guidelines (in water of at least 60 degrees celsius where possible).  allocating a dedicated room in case temporary isolation is required. 3. risk stratifying the sport  stratifying individual sports with no physical contact as low risk (e.g. singles tennis and golf) while classifying contact and collision sports (team or individual, such as football and rugby) as high risk.  considering the number of essential persons required at the event, as well as spectators, media and non-essential staff in the risk strategy.  accounting for the ventilation of the playing area where unventilated areas will be considered as higher risk while those held outdoors will be considered as lower risk. 4. risk stratifying the participants  daily screening, aligned to the recommendations of the doh, using an app or paper-based questions to identify symptomatic individuals prior to arriving at training sessions.  the taking of temperatures daily when entering the sporting environment.[2]  identifying and preventing the attendance and participation of higher-risk participants (those older than 60 years and those with comorbid diseases). 5. practical implementation of guidelines  initially forbidding the gathering of any groups during events (no parents etc., only officials and competing individuals).  in lockdown level 3, minister nkosazana dlamini zuma indicated that more time will be allowed for exercise as long as it is well organised with the observation of social distancing and healthy practices. non-contact sports may resume without spectators.[17]  recommending outlines on when not to come to training and what the reporting lines are e.g. coach, manager, and health authorities.  avoiding public transport to get to training/matches.  detailing and availing an action plan in the case of a suspicious case (including targeted tracing) – this may need medical guidance (even remotely).  considering the higher risk of injury in the return-to-sport strategy.[18,19] sasma acknowledges that several federations in south africa have drafted sports-specific guidelines for the potentially exposed and the infected athlete. based on international guidelines, sasma recommends the following approach: 1. all athletes:  ensuring physical, psychological and competitive equity to athletes to allow them time to return to their previous level of fitness before major events are rescheduled.[20]  upholding the principles of social distancing and hand hygiene.[7] 2. athletes that were exposed to individuals who were affected by covid-19:  those at high risk (were closer than one metre to the infected person or in contact for more than 15 min), and medium risk (>one metre or less than 15 min contact),[21] need to follow the guidelines for self-quarantine, namely 14 days whilst monitoring for symptoms of covid-19.  alerting their medical provider if they have symptoms in order to undergo further investigations, including a polymerase chain reaction (pcr) test.[22]  if testing is positive, following the “infected person protocol” as dictated by the doh and nicd.[23]  if they display no symptoms during these 14 days, they may follow a guided return to sport, ensuring load is started at low intensity and progressed. 3. athletes who were infected and tested positive:  these athletes need to avoid exercise for the recommended seven to ten days after cessation of symptoms (approximately 21 days from onset of symptoms).[9]  they must follow doh/nicd isolation protocols.[23]  they should be monitored daily if they are self-isolating. any worsening of symptoms should be reported to the dedicated health officer.  there is no disease-specific treatment to be prescribed for position statement 5 sajsm vol. 32 no. 1 2020 covid-19; symptomatic treatment is advised. 4. following 14 days of isolation or recovering from the disease:  it is recommended that these athletes have 2 covid-19 tests at least 48 hours apart that are negative.  in any event, clinical monitoring, inflammatory markers and cardiovascular monitoring should be implemented.[24]  ensure cardiac screening, which should include a resting and effort ecg, and cardiac echo.[25] the stress ecg must only be done ≥ seven days after the mandatory 14 days isolation and at least seven to ten days after symptom resolution.  a cardiologist should clear the athlete before commencing exercise due to the possibility of developing a viral myocarditis. 5. positive tests after the mandatory isolation period:  the above protocol implies a mandatory 21 day period of stand down before an athlete can resume training after a positive test. this can last up to three months or however long it takes until symptoms resolve and the clearance protocol is complete.  it is recommended that in these cases[26], the same protocol must be followed as in point 4.  the return-to-sport approach must be more cautious in these cases.[7,27]  these athletes, upon return to training, must be screened daily as per usual.  any recurrence of symptoms must be addressed accordingly and urgently. 6. other medical conditions:  because covid-19 has poorer outcomes in cases with comorbidities, such as diabetes mellitus, cardiac disease, hypertension and cancer[27,28], any such existing conditions must be appropriately treated. conclusion in conclusion, it is important that persons charged with managing athletes’ return-to-sport in any environment must be up-to-date with local and international trends, transmission rates, regulations and sport-specific rule changes that might develop as sport resumes. additionally, such information should be applied in a sports-specific manner, considering individual athlete’s and team needs and be consistent with national legislation. disclaimers: this document has been compiled as a guide for safe retur n to sports, and should be used as such. it is still the responsibility of organisers to ensure that facilities for training are compliant with directives by who, nicd and doh, and updates should be adhered to. please use the information for its intended use, i.e. as a guide to assist in sport resumption. this document is not a tool to return to sport prematurely, but should be used aligned with the statutory guidelines (which may change constantly and differ from area to area). conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. approved by: south african sports medicine association (sasma) executive committee author contributions: drafting the paper: da ramagole, dc janse van rensburg, l pillay. content review: p viviers, p zondi, j patricios. references 1. carmody s, murray a, borodina m, et al. when can professional sport recommence safely during the covid-19 pandemic? risk assessment and factors to consider. br j sports med. published online ahead of print: 07 may 2020. [doi.: 10.1136/bjsports-2020102539] [pmid: 32381501] 2. world health organization. guidance for the use of the who mass gatherings sports: addendum risk assessment tools in the context of covid-19. who global; 30 apr 2020. available from: https://www.who.int/publications/m/item/guidance-for-the-useof-the-who-mass-gatherings-sports-addendum-risk-assessmenttools-in-the-context-of-covid-19 3. filatov a, sharma p, hindi f, et al. neurological complications of coronavirus disease (covid-19): encephalopathy. cureus 2020;12(3):e7352. [doi:10.7759/cureus.7352] [pmid: 32328364] 4. hull jh, loosemore m, schwellnus m. respiratory health in athletes: facing the covid-19 challenge. lancet respir med 2020; 8(6): 557-558. [doi: 10.1016/s2213-2600(20)30175-2] [pmid: 32277869] 5. xiong ty, redwood s, prendergast b, et al. coronaviruses and the cardiovascular system: acute and long-term implications. eur heart j 2020;41(19):1798-1800. 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(part 2) international olympic committee consensus statement on load in sport and risk of illness. br j sports med 2016;50(17):1043-1052. [doi: 10.1136/bjsports-2016-096572] [pmid: 27535991] 10. pillay l, janse van rensburg dc, jansen van rensburg a, et al. nowhere to hide: the significant impact of coronavirus disease 2019 (covid-19) measures on elite and semi-elite south african athletes. j sci med sport 2020;s1440-2440(20)30602-2. [doi:10.1016/j.jsams.2020.05.016] [pmid: 32448749] 11. jukic i, calleja-gonzález j, cos f, et al. strategies and solutions for team sports athletes in isolation due to covid-19. sports (basel) 2020;8(4):56. [doi: 10.3390/sports8040056] [pmid: 32344657] 12. simpson rj, katsanis e. the immunological case for staying active during the covid-19 pandemic. brain behav immun 2020:s08891591(20)30573-30580. 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[doi:10.1001/jamacardio.2020.2136] [pmid: 32402054] 15. ais. prescription of training load in relation to loading and unloading phases of training. 2015. australian institute of sport. available from: https://rowingaustralia.com.au/wpcontent/uploads/2015/02/ais-whitepaper-on-load.pdf. 16. sascoc cannot prescribe to federations when to resume sporting activities. media release, 2020. available from: https://www.sascoc.co.za/2020/05/17/sascoc-cannot-prescribe-tofederations-when-to-resume-sporting-activities/ 17. wits institute for sport and health (wish). wish covid-19 and sport guidelines risk reduction and stratification for sports and exercise 2020. wits university. 2020. available from: https://www.wits.ac.za/media/wits-university/students/witssport/documents/wish%20covid19%20and%20sport%20guidelines.pdf. 18. summary of level 3 lockdown regulations. media release, 2020. available from: https://sacoronavirus.co.za/2020/05/28/summaryof-level-3-regulations/ 19. myer gd, faigenbaum ad, cherny ce, et al. did the nfl lockout expose the achilles heel of competitive sports? j orthop sports phys ther 2011;41(10):702‐705. 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[doi:10.1177/1941738120918876] [pmid: 32250193] 26. nieß a, bloch w, friedmann-bette b, et al. recommendations for exercise testing in sports medicine during the current pandemic situation (sars-cov-2/covid-19). german journal of sports medicine 2020; 71(5): e1-e2 [doi.org/10.5960/dzsm.2020.438] 27. kang y-j. south korea’s covid-19 infection status: from the perspective of re-positive after viral clearance by negative testing. disaster med public health prep, 2020.1-3. published online ahead of print. [doi:10.1017/dmp.2020.168] [pmid: 32438941] 28. jordan re, adab p, cheng kk. covid-19: risk factors for severe disease and death. bmj 2020;368:m1198. [doi:10.1136/bmj.m1198] [pmid: 32217618] 29. gémes k, talbäck m, modig k, et al. burden and prevalence of prognostic factors for severe covid-19 disease in sweden. eur j epidemiol 2020;35(5):401–409. [doi: 10.1007/s10654-020-00646-z] [pmid: 32424571] https://rowingaustralia.com.au/wp-content/uploads/2015/02/ais-whitepaper-on-load.pdf https://rowingaustralia.com.au/wp-content/uploads/2015/02/ais-whitepaper-on-load.pdf https://www.wits.ac.za/media/wits-university/students/wits-sport/documents/wish%20covid-19%20and%20sport%20guidelines.pdf https://www.wits.ac.za/media/wits-university/students/wits-sport/documents/wish%20covid-19%20and%20sport%20guidelines.pdf https://www.wits.ac.za/media/wits-university/students/wits-sport/documents/wish%20covid-19%20and%20sport%20guidelines.pdf original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the physical attributes of sub-elite rugby union referees of inland provinces in south africa c le roux, ba honours (sport science); a lombard, msc; a green, phd department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa corresponding author: c le roux (conradlr89@gmail.com) rugby union is contested by two teams, each consisting of 15 players. the objective of the game is to outscore the opponent by means of tries, penalties and conversions. the laws of the game are interpreted and applied by an onfield referee and two assistant referees.[1] the on-field referee is primarily responsible for officiating the entirety of match play, including player behaviour, imposing penalties and adjudicating the competition; whilst the touch judges and assistant referees assist with matters relating to the side-lines, in-goal play, including attempted goal kicks and reporting foul play.[2] the panel of referees can be expanded for higher competitive level matches to include fourth and fifth assistant referees who regulate match substitutions and other duties.[3] the on-field referees are required to keep up with play and to position themselves in favourable positions to make appropriate decisions. as such, they must attain similar movements and velocities to the rugby players. rugby players cover on average 5 800 m during a game, interspersed between bouts of various velocities and intensities. this indicates that for 80 minutes the players require a variety of aerobic and anaerobic capacities.[4-8] moreover, player demands include physical collisions and largely static efforts, such as rucking and scrummaging.[9] however, unlike the players, referees are not required to participate in physical contests, but are required to maintain similar physical efforts to the players. referees play a pivotal role in match progression and outcome. they need to interpret a massive amount of information to make fast, clear and correct decisions about the game.[5] a referee needs to manage a game in a unique environment, influenced by the quality of the game, the attitude of the players and spectators, while ensuring peak physical performance. the referee undertakes highintensity running in open play and must be visible, without interfering with a team’s progress.[7] once open play has stopped (tackle, ruck, maul), the referee will need to slow down and be in a position to make an appropriate call. it is therefore essential that they are able to slow down and change direction to where they can optimally locate the ball. the total average distance covered by referees during a rugby match is usually 6 400 m.[3] of the total distance, approximately 881 s is spent standing still, 736 s walking, 346 s jogging, 139 s sprinting and lastly, 372 s spent moving laterally.[6] referees covered the majority of the distance at velocities of between 0.51–2.00 m.s-1 and 2.01–4.00 m.s-1 [3], interspersed with efforts at higher velocities, thus demonstrating the intermittent nature of the required movement patterns during the game.[6] cunningham et al. reported that there are no significant differences in the running performances for referees from the first half to the second half , although the first 10 minutes consisted of the most intense work of all the 10 minute periods in the game.[11] bester and colleagues[8] reported that referees had an average heart rate of 186.5 beats per min with an eight percent difference in heart rate between the two halves. these findings indicate that rugby refereeing is highly intense, placing high demands on a referee’s aerobic and anaerobic energy systems.[12] thus for 80 minutes a referee will need good aerobic capacity and the ability to stay mentally focused for that duration of time to make accurate decisions. however, the physical demands of players and referees during a game may not be equal, and different physical and physiological parameters are required. furthermore, these differences between players and referees may require different training requirements. this study aims to establish the physical attributes of sub-elite rugby referees, highlighting the physical preparation that the referee goes through to meet the demands of the game and their anthropometric values. methods this was a descriptive cross-sectional study determining the physical attributes of sub-elite referees. sub-elite referees were defined as referees who adjudicate amateur level rugby and do not serve on the south african referee union panel. three background: the purpose of the on-field referee is to implement the laws of the game. for the referee to do this successfully, he is required to keep up with the pace of play. objectives: the aim of this study was to determine the physical attributes of sub-elite rugby union referees of inland provinces in south africa. methods: a total of 82 referees (age: 26.5 ± 6.4 years; stature: 177.3 ± 6.8 cm; body mass: 79.1 ± 14.7 kg) were assessed with a reliable testing battery. results: the participants showed a refined aerobic capacity (vo2max: 61.8 ± 11.0 ml·min-1·kg-1) and good agility (illinois agility test: 17.2 ± 3.8 s). a two-way unbalanced anova was performed for all referees’ attributes between qualification levels (levels 1-4) and union affiliations (three unions) at a significance level of p<0.05. the results yielded significant differences across the three unions in age (p=0.002), yo-yo distance (p=0.0001), aerobic capacity (p=0.0001), plank time (p=0.0001) and agility (p=0.027). similarly, differences were reported across the four qualifications in aerobic capacity (p=0.0001) and agility (p=0.037). conclusion: these differences may be due to the diverse training programmes offered by the various unions. additionally, an increased level of physical fitness may occur when progressing up the qualification levels. keywords: field testing, match officials, performance, morphology s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a8835 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a8835 https://orcid.org/0000-0003-3969-1411 https://orcid.org/0000-0002-2434-5818 https://orcid.org/0000-0002-0275-0070 original research sajsm vol. 33 no. 1 2021 2 unions were selected for this study based on their proximity to the research institution. two major rugby unions from gauteng and one from the north west province were selected. a sample of 82 referees from three unions (age: 26.5 ± 6.4 years; stature: 177.3 ± 6.8 cm; body mass: 79.1 ± 14.7 kg and body fat percentage: 10.9 ± 3.2%) with an average of 2.8 ± 1.7 years’ experience volunteered and signed the informed consent form to participate in this study. all ethical procedures were reviewed and approved by the faculty of health sciences ethics committee (rec -01-153-2017), university of johannesburg. procedure body mass and stature were assessed with an electronic scale (813 seca, hamburg germany) and stadiometer (213 seca, hamburg germany). body fat percentage (harpenden sussex, england) was calculated using the sum of six skinfolds method as proposed by davies et al.[9] flexibility was assessed by means of a standard sit-and-reach box[10] to the nearest millimetre. aerobic capacity was estimated using the yo-yo intermittent recovery test[11] and agility by means of the illinois agility test.[12] upper body muscle endurance was assessed using the one minute push-up test[10] and the plank hold for the same time.[13] the standing long jump test[14] (or broad jump test) was used to estimate lower limb muscular power. all procedures were conducted in a single training session at the rugby union’s training facilities. this testing protocol has many similarities to the boksmart study ensuring that it relates to the demands of south african rugby.[14] data analysis the sample was divided into the three unions and the respective qualification levels. qualification levels are ranked from one to four, with one being the highest amateur referee ranking level. the higher qualified referees have completed more world rugby officiating courses. due to upper body injuries on the day of testing, the sample sizes for the various tests had some discrepancies in the number of referees participating statistical analysis data are presented as mean ± standard deviation. the shapiro-wilk test was performed on each variable to determine their distributions. an unbalanced two-way anova (qualification level x union affiliation) was conducted for each variable across the affiliated unions and qualification levels, followed by bonferroni post hoc tests. all statistical analyses were performed using spss 24 (ibm), and significance was defined at a level of p < 0.05. results anthropometric and physical performance tests for the 82 rugby referees are reported in table 1. for age, a large significant interaction (p=0.0001) was identified between the referees’ qualification level and union affiliation (table 2). in addition, significant differences were noted between referee affiliations (unions) for age (p=0.002), yo-yo distance (p=0.0001), estimated vo2max (p=0.0001), plank time (p=0.0001), but not in their qualification level (age: p=0.131; yo-yo distance: p=0.087; estimated vo2max: p=0.106; plank time: p=0.389). referees affiliated with union 1 were older than those affiliated with union 2 (p=0.01) but not union 3 (p=1.00). of the three unions, referees affiliated with union 2 covered the lowest distance in the yo-yo intermittent recovery test (p=0.0001) and subsequently had the lowest estimated vo2max (p=0.0001). regarding plank performance, referees associated with union 2 recorded the lowest times compared to those related to union 1 (p=0.0001) and union 3 (p=0.0001). the results from the two-way anova (table 2) indicated a significant interaction for the time taken to complete the illinois agility test by referees between their qualification and union (p=0.029). additionally, there were significant differences in the illinois agility test’s completion times between unions (p=0.027) and qualification (p=0.037). referees affiliated with union 1 outperformed referees affiliated with union 2 (p=0.006). furthermore, referees with qualification level 1 outperformed those with qualification level 3 in the illinois agility test (p=0.035). no further differences were noted between the affiliated unions or qualification levels in the illinois agility test (table 2). lastly, there were no significant differences for height (p=0.778), weight (p=0.150), body fat percentage (p=0.164), sit-and-reach (p= 0.828), push-up (p= 0.045) and the broad jump (p=0.425) (table 2). discussion the study aimed to establish the physical attributes and performance parameters of sub-elite rugby referees of inland provinces in south africa. a sample group of 82 referees were tested and subsequently divided into registered unions and qualification levels to investigate any potential differences. with regard to the unions and qualifications, there were differences in age, aerobic capacity, agility, and muscle endurance. referees are required to keep up with play to determine the outcome of the game and make important decisions about what they see in front of them during the game. therefore, one would expect referees to have similar in-game demands as players. in table 1. anthropometric and physical performance characteristics of 82 rugby union referees characteristic mean ± sd height (cm) 177.3 ± 6.8 body mass (kg) 79.1 ± 14.7 body fat (%) 10.9 ± 3.2 sit and reach (cm) 30.8 ± 9.5 yo-yo intermittent recovery test (m) 2910 ± 750 estimated vo2max (ml/kg/min) 61.8 ± 11.0 illinois agility test (s) 17.2 ± 3.8 push-ups (repetitions) 39 ± 6 plank (s) 145 ± 40 standing broad jump (m) 2.1 ± 0.3 original research 3 sajsm vol. 33 no. 1 2021 sdsdsds table 2. anthropometric and physical performance characteristics of 82 rugby union referees compared across union affiliation and qualification level characteristic qualification level union 1 union 2 union 3 total for qualification levels age (years) †*# 1 27.2 ± 6.3 26.6 ± 5.3 26.5 ± 2.8 26.6 ± 5.3 2 28.7 ± 4.8 28.3 ± 7.5 28.6 ± 5.4 3 24.2 ± 9.4 22.4 ± 5.5 23.3 ± 7.4 4 40.0 ± 0.0 19.7 ± 3.0 24.2 ± 9.3 total for unions 27.7 ± 7.0 23.7 ± 5.4 26.5 ± 2.8 26.1 ± 6.2 height (cm) 1 178.6 ± 5.7 177.7 ± 8.4 175.2 ± 5.3 177.7 ± 6.4 2 175.4 ± 7.1 180.2 ± 6.7 177.0 ± 7.0 3 176.4 ± 8.8 174.5 ± 6.6 175.5 ± 7.4 4 173.5 ± 6.0 178.8 ± 7.3 177.6 ± 7.0 total for unions 177.5 ± 6.3 177.7 ± 7.4 175.2 ± 5.3 177.3 ± 6.6 weight (kg) 1 80.1 ± 9.9 81.5 ± 10.0 78.2 ± 11.0 80.1 ± 10.0 2 79.3 ± 13.8 82.1 ± 3.9 80.2 ± 11.2 3 72.8 ± 12.8 79.9 ± 15.9 76.4 ± 14.1 4 67.1 ± 7.7 83.4 ± 22.9 79.7 ± 21.3 total for unions 78.3 ± 11.1 81.8 ± 14.3 78.2 ± 11.0 79.6 ± 12.3 body fat (%) 1 10.6 ± 3.6 10.9 ± 1.9 10.6 ± 2.8 10.7 ± 3.0 2 14.0 ± 5.3 10.3 ± 1.3 12.7 ± 4.6 3 9.0 ± 2.3 9.7 ± 2.8 9.3 ± 2.4 4 12.3 ± 3.4 9.6 ± 1.7 10.2 ± 2.2 total for unions 11.0 ± 3.9 10.2 ± 1.9 10.6 ± 2.8 10.7 ± 3.2 sit and reach (cm) 1 31.6 ± 10.6 29.0 ± 11.7 32.4 ± 8.2 31.1 ± 10.3 2 29.9 ± 7.8 22.7 ± 3.2 27.5 ± 7.3 3 30.1 ± 7.8 34.4 ± 9.0 32.3 ± 8.2 4 27.0 ± 4.2 30.9 ± 6.5 30.0 ± 6.1 total for unions 30.9 ± 9.5 29.8 ± 9.6 32.4 ± 8.2 30.7 ± 9.3 yo-yo intermittent recovery test (m) # 1 3372 ± 385 2285 ± 724 3470 ± 158 3115 ± 671 2 3103 ± 504 1873 ± 689 2693 ± 810 3 3408 ± 254 2168 ± 569 2788 ± 774 4 2440 ± 198 2123 ± 689 2193 ± 617 total for unions 3285 ± 435 2176 ± 659 3470 ± 158 2910 ± 750 estimated vo2max ml·min-1·kg-1 # level 1 68.3 ± 4.9 52.2 ± 10.2 71.6 ± 4.1 64.9 ± 9.9 level 2 64.8 ± 6.5 46.4 ± 9.9 58.7 ± 11.7 level 3 68.8 ± 3.2 50.7 ± 8.1 59.8 ± 11.2 level 4 56.0 ± 2.8 49.9 ± 9.5 51.3 ± 8.7 total for unions 67.2 ± 5.6 50.7 ± 9.3 71.6 ± 4.1 illinois agility test (s) †*# level 1 16.0 ± 0.9 17.5 ± 1.3 16.8 ± 0.6 16.6 ± 1.1 level 2 16.5 ± 1.1 16.6 ± 0.6 16.5 ± 0.9 level 3 15.8 ± 1.2 24.3 ± 13.8 20.1 ± 10.3 level 4 17.6 ± 0.4 18.4 ± 2.0 18.2 ± 1.7 total for unions 16.2 ± 1.0 18.9 ± 6.2 16.8 ± 0.6 17.2 ± 4.0 push-up (reps) level 1 38 ± 15 46 ± 16 49 ± 10 42 ± 15 level 2 28 ± 17 50 ± 5 35 ± 17 level 3 42 ± 20 31 ± 15 37 ± 1 level 4 22 ± 6 35 ± 15 33 ± 15 total for unions 36 ± 16 41 ± 16 49 ± 10 39 ± 16 plank (s) # level 1 159 ± 30 123 ± 32 180 ± 0 155 ± 33 level 2 125 ± 43 140 ± 45 130 ± 42 level 3 177 ± 6 106 ± 41 141 ± 47 level 4 147 ± 47 110 ± 51 119 ± 50 total for unions 156 ± 34 119 ± 40.0 180 ± 0 146 ± 40 broad jump (m) level 1 2.2± 0.3 2.1 ± 0.4 2.0 ± 0.2 2.1 ± 0.3 level 2 2.0 ± 0.2 2.2 ± 0.2 2.1 ± 0.2 level 3 2.2 ± 0.2 2.0 ± 0.3 2.1 ± 0.2 level 4 1.8 ± 0.1 2.1 ± 0.3 2.0 ± 0.3 total for unions 2.1 ± 0.3 2.1 ± 0.3 2.0 ± 0.2 2.1 ± 0.3 data are expressed as mean ± sd. † interaction between qualification levels and union affiliations (p<0.0001); * significance difference across qualification levels (p<0.05); # significant difference across unions (p<0.05) original research sajsm vol. 33 no. 1 2021 4 comparison to rugby union referees, rugby players run 500 m less per game than rugby union referees.[4] rugby players averaged 1 506 m in the yo-yo intermittent recovery test compared to the rugby referees who averaged 2 910 m.[15] however, one component exclusive to players is that of frequent collisions[16] rugby players are about 18 kg heavier and 19 cm taller than most referees.[9] over recent years, rugby players have become heavier and taller, possibly indicating the importance of collisions and physical contact in modern rugby.[11,17] however, the requirements of refereeing versus playing are vastly different. as such, comparisons will be conducted with non-contact football codes. interestingly, when comparing rugby union referees with football referees, football referees run 4 000 m more per game.[18] this could be due to the time differences between the football codes, field dimensions and different running patterns required. it is noted that football referees are about seven kg lighter and have about two percent less body fat[19] than the rugby union referees presented in the current study. lastly, elite rugby union referees covered on average 8 030 m[7] per game which is significantly more than the sub-elite referees.[3] this could be attributed to the playing levels and physical condition differences between the referees. a reduced mass and body fat percentage may be advantageous, allowing referees to effectively cover greater distances. indeed, elite referees have been reported to have similar body masses (83.4 kg) and body fat percentages (11.6%), compared to those reported in the current study.[8] additionally, the difference in anthropometrics between referees in both codes may be due to many of the referees being ex-players. irrespective of the in-game demands, referees require refined physical and physiological attributes to perform. rugby referees will have repeated efforts of running bursts with times to rest during the stoppages in games.[4] therefore, the yo-yo intermittent recovery test is an appropriate test for rugby referees as it closely matches the running demands of the game.[15] rugby referees in this study averaged 2 910 m in the yo-yo intermittent recovery test, which is the same distance as that for football referees.[20] the yo-yo intermittent recovery test can be used to estimate the participant’s vo2max. the total sample estimated vo2max was 61.8 ml·min-1·kg-1 compared to the soccer referees’ 50.2 ml·min-1·kg-1 on the treadmill and 48.6 ml·min-1·kg-1 during the field tests.[21] this substantial difference could be due to the two different test protocols used to determine the vo2max. the two protocols used were the yo-yo intermittent recovery test estimation versus direct lab measurements on the treadmill.[21] the ability to rapidly accelerate, decelerate and change direction is essential for the referees to keep up with the demands of the game. if referees are competent with these skills they will be in a better position to adjudicate the game optimally. when comparing rugby and football referees, they performed the same, namely, 17.2 seconds to complete the illinois agility test.[22] a standing broad jump can be used to estimate lower limb power. professional football referees outperformed rugby referees in the current study by 10% in the standing broad jump. those football referees were professional referees[19] which could be the main reason for the difference in performance, as the rugby sample group are amateurs. differences across teams, leagues and playing levels in players and referees is well documented.[23] the current study investigated these differences by dividing the whole sample into three groups, based on their affiliated unions. there are marked differences in how the game is played at international level between northern hemisphere and southern hemisphere countries.[24] likewise, differences can be seen in the same sporting code but playing in different leagues.[25] a similar difference can be expected inter-provincially and between different unions in the same country. several physical performances were reported to be different across the three unions namely, the yo-yo intermittent recovery test, estimated vo2max, the illinois agility test, and the muscle endurance tests. these differences between unions could be due to union training preferences, education, and the overall level of the game being played in that union. specifically, referees from union 2 were the youngest, which could be due to the fact that they come from a university town and had just started their refereeing career. union 2 also covered the least distance in the yo-yo intermittent recovery test thus resulting in the worst score on the estimated vo2max. lastly, union 2 also performed worst in the plank hold test compared to the other two unions. as previously mentioned, union 2 was the youngest of the unions resulting in less experience, a younger training age, and the lowest understanding of what is expected from them physically. referees should be assessed numerous times during a year to give them an appropriate level of competency and to monitor their physical fitness levels. level 1 referees are more highly qualified compared to those in level 4. the more highly qualified referees completed more courses such as the world rugby level 2 officiating course and performed better on the yearly written and fitness exams. it would seem as though unions have a large influence over the physical abilities of referees. that is, the results from the current study indicated many differences in the physical capabilities with the yo-yo intermittent recovery test, the illinois agility test and plank hold tests. these differences could indicate the different unions’ implementation of training protocols, testing and physical preparedness for referees. additionally, the intensity of matches at the various union levels may be different, depending on the leagues in which they compete. a similar trend is seen with athletes across various codes.[26] it is widely reported that physical performances increase with an athlete’s playing level.[27] thus, the data reported in the current study show that qualification levels in rugby referees are analogous with an athlete’s playing level. the more experienced referees all had the highest qualification levels. these referees performed the best in the illinois agility test, indicating that the ability to change direction is critically important. this could mean that the referees’ qualification levels and experience may provide them with greater physical preparation for games, as they are more aware of the matches’ demands. however, further detailed investigations are required. ‘ original research 5 sajsm vol. 33 no. 1 2021 conclusion for referees to keep up with the demands of the game, they require high aerobic capacity, muscular endurance and strength. if the referee can refine these physical attributes, they can position themselves better leading to more accurate decisions in the game. this will ensure that it is played fairly, and make it enjoyable for all. there are many differences between the unions related to the parameters tested in this study. thus the different standards between the unions, may be due to the incompatible education or training programmes offered by the unions. an improved level of fitness should occur when progressing up the qualification levels similar to the changes seen in the players, but more research is required on this. practical applications rugby referees should follow a high-intensity intermittent interval training programme similar to that followed by the rugby players (without the contact components). additionally, components of speed and agility training should be incorporated into their training programmes. national and international bodies are encouraged to create a standardised protocol to test the physical abilities and readiness of referees. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: clr: study design, data collection, data and statistical analysis, manuscript draft and corrections (primary author). al: study design, data collection, data analysis, manuscript review. ag: study design, data and 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[doi: 10.5114/biolsport.2019.88755] [pmid: 319380003] file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1123/ijspp.2013-0270 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1123/ijspp.2013-0270 https://doi.org/10.1080/02640414.2013.773401 https://dx.doi.org/10.5114%2fbiolsport.2019.88755 original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license evolving injury profiles amid advancing sport: musculoskeletal injuries in ringball players j d pillay,1 phd; j wiggill,2 mtech; b n mkhwanazi,3 phd 1 department of basic medical sciences, faculty of health sciences, durban university of technology, south africa 2 department of chiropractic, faculty of health sciences, durban university of technology, south africa 3 school of agricultural, earth & environmental sciences, university of kwazulu-natal, private bag x101 scottsville, south africa corresponding author: b n mkhwanazi (mkhwanazib@ukzn.ac.za) ringball, formerly known as ’korfball’, is a noncontact, family-orientated team sport played by both males and females, comprised of elements from netball and basketball. in 1902, a dutch primary school teacher developed the sport,[1] then called korfball. the reason for the creation of korfball was to encourage both males and females to participate in the sport on an equal basis.[1] between 1907 and 1916, korfball was played under the south african basketball union and introduced into afrikaans-speaking schools. korfball was then made a provincial sport that became nationally and internationally recognised. there are currently approximately 2 500 players in south africa from all nine provinces who compete against each other annually.[2] in 2007, the name was changed to ’ringball’ and in 2010 the international ringball federation was formed, which introduced ringball to the world.[2] ringball consists of passing the ball between players with the intention of scoring a goal by shooting it into a basket above the ground, each one of which is situated on either side of the court, as in basketball and netball.[3] these sports have different game rules and court types.[4] for example, ringball has nine players while netball and basketball have seven and five players respectively. in netball, the player receiving the ball, must come to an immediate stop and stay on the same foot on which he/she landed and play the ball without moving this foot.[5] the gameplay of basketball is a continuous flow of running and walking while dribbling the ball in motion.[6] in ringball, once the ball is received, the player is allowed to take an extra two to three steps before stopping, reducing the sudden force on the knee, foot and ankle.[7] these differences can be important in the type and extent of injuries sustained as a result of changes in the flow of motion. another difference relates to shooting for a goal. in ringball, when a shooter wants to shoot for a goal he/she must be positioned outside the goal area or half circle. the elbow must be slightly flexed below the shoulder and the forearm and hand facing laterally upwards towards the head whilst holding the ball with both hands. the shooter throws the ball with both hands in an underhand motion (from below upwards) towards the head so as to allow for the rotation of the ball towards the goal’s ring. the ball must leave the goal shooter’s hand below the shoulder and must enter the goal net from above.[7] in both basketball and netball, when standing/jumping to throw the ball to the goal net, the shooting elbow is in full flexion with the forearm pronated towards the net. the ball then leaves the hand which is in full flexion.[5, 6] in basketball, any player can score points by throwing the ball through the hoop whether they are inside or outside of the half circle.[6] the further away from the hoop the player is when he/she releases the ball, the greater the number of points that can be scored.[6] differences in basketball and netball often present with contrasting associated injuries that commonly occur.[8] there is a great similarity in the injuries between the sports, but there are also differences between the most common and least common injuries.[8] the most common injuries reported in basketball are foot/ankle and knee injuries, which make up 40% and 15% of all injuries, respectively.[9] the most common injuries reported in netball are ankle injuries, which make up 38% of injuries and knee injuries making up 29% of all injuries.[10] the least common injuries found in basketball are background: ringball, a sport historically derived from conventional basketball and netball, demonstrates the evolution of traditional sport. the variations between these sports may predispose players to different risk factors and consequent injuries and their impact, yet they are usually considered comparably. objective: to determine the prevalence of musculoskeletal injuries and to profile injuries based on location, severity, and mechanisms of occurrence. a further objective was to compare the injuries sustained in ringball with that of basketball and netball. methods: a questionnaire-based study, administered to 110 ringball players in kwazulu-natal, south africa, was applied. data were described and compared using frequencies/ percentages for categorical variables. results: seventy-six ringball players completed the questionnaire (69% response rate). the prevalence of at least one injury during/after the last or current season was 80% (n=61). the most commonly reported injury was to the foot/ankle (36%; n=33) followed by the knee (29%; n=27) and wrist (9%; n=8). the most common mechanisms of injury reported were landing (15%; n=9), jumping (9%; n=5), goal shooting (7%; n=4), defending (7%; n=4) and collision (7%; n=4). discussion: ringball shares similar injuries to that of basketball/netball, with foot/ankle injuries being the most prevalent. the prevalence of other injuries in ringball differed from basketball/netball, suggesting variations between these sports as a contributor to the injuries described. conclusion: the evolution of sport and the modifications in rules/techniques may create a nuanced injury profile to those commonly identified. the combination of a sport’s uniqueness/modification and its similarities to other sports warrants the need for more tailored approaches to injury prevention and a platform for future research. keywords: risk factors, prevalence, mechanism of injury s afr j sports med 2020;32:1-6. doi: 10.17159/2078-516x/2020/v32i1a8166 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8166 https://orcid.org/0000-0003-1181-3587 https://orcid.org/0000-0001-8502-8878 https://orcid.org/0000-0003-2504-6286 original research sajsm vol. 32 no. 1 2020 2 face/head/neck (14%), hand/arm (10%) and the upper leg/thigh and hip (8%).[9] the least common injuries found in netball are the leg (7%), hand and wrist (7%), shoulder (6%), back (5%), thigh (3%), neck, head, chest (3%) and elbow/arm (3%).[10] whilst there is similarity in the two sports, differences appear between them in terms of the most common and the least common injuries. as expected, ringball may also show differences, and despite being played for approximately 100 years, there is limited information on the injuries sustained in this sport.[2] the aim of this study was therefore to determine the prevalence of musculoskeletal injuries in ringball players and to profile the different types of musculoskeletal injuries based on location and severity, as well as the mechanisms of injury in the sport. the research undertaken further compares injuries in ringball to those found in basketball and netball given that ringball is derived from both sports. by documenting the risk factors and injuries sustained in terms of location, severity and mechanisms/aetiology of injury, primary measures can be applied to reduce injury occurrence and help manage injuries. such measures may support the development of guidelines and protocols for sport-specific injury prevention and management. methods study design a questionnaire-based cross-sectional approach was used in this study. population size and participant recruitment participants were recruited from six registered ringball clubs in kwazulu-natal (kzn). there were approximately 152 ringball players from 16 teams, all over the age of 16 years. if the participants were under the age of 18 years, the parents or legal guardians completed the parental informed consent, accompanied by an informed permission for minors. the sample size that was required for adequate statistical power was determined to be 110, of which a 70% response rate would obtain appropriate generalisability. ethical approval was granted by the institutional research ethics committee (irec 35/18) at the durban university of technology. gatekeeper permission was obtained from the president of the kzn ringball federation. informed consent was obtained from all participants. measurement tools this consisted of a self-administered questionnaire which was adapted and contextualised from a validated questionnaire titled: ‘a profile of soccer injuries in selected league amateur indoor and outdoor soccer players in the greater durban area’.[11] a focus group reviewed the modified questionnaire that was subsequently piloted, with relevant modifications made before it was administered to the participants. data reduction and analysis a microsoft excel spreadsheet was used to capture the data, and then ibm spss version 25 was used to analyse the data. a descriptive analysis was undertaken to highlight demographics, frequencies and percentages in the case of categorical variables for the prevalence of the injury, mechanism of the injury, and the location and severity of the injury. results of the 110 questionnaires administered, 76 were completed, from 31 (41%) male and 45 (59%) female respondents. this resulted in a response rate of 69%. the mean age reported in males was 29.911.3 years and in females was 31.912.6 years. the prevalence of musculoskeletal injury all the ringball players who participated in this research study had played at least one season/year of ringball. the prevalence of experiencing an injury over the last and/or current season was 80% (n=61), with some participants reporting more than one injury: 43% reported one injury,13% reported two injuries, 11% reported three injuries, 4% reported four injuries and 9% reported more than four injuries sustained (fig. 1). location of injury of the 93 reported injuries among 61 participants, the most common locations of injuries were the foot/ankle (36%), the knee (29%) and the wrist (9%), respectively. the least common locations of injuries were the head/neck, forearm and genitals at 1% each. mechanisms of injury table 1 shows the mechanisms of injury for the first reported injury. the results revealed that the most common mechanisms were incorrect landing 15% (n=9), jumping 9% (n=5), goal shooting 7% (n=4), defending 7% (n=4), collisions 7% (n=4); and other mechanisms 7% (n=4). severity of injury severity was estimated by using the number of training sessions or matches missed due to the injury as a proxy. table 2 shows the extent of the severity of the injuries by considering the number of sessions that were missed. of the 61 participants who experienced at least one injury, 59 responded to the question on the number of training sessions missed. hence some participants may have been injured as a result of training sessions missed but did not answer this question. fifty-eight players reported on the number of competitive matches missed due to their first injury. of the 58 players, 10% (n=6) reported missing one competitive match, 16% (n=9) two matches, 12% (n=7) three matches, 5% (n=3) four matches and 24% (n=14) more than four competitive matches. another estimate that was used as a proxy to determine the injury severity was the number of days that were missed due to an injury. table 3 shows the extent of the severity of the injuries by taking into account the number of days that were missed in each case. the number of days that the players were unavailable for training and competitive matches for their reported injury was highlighted. a total of 56 participants reported the number of days they original research 3 sajsm vol. 32 no. 1 2020 were unavailable for training. out of the 56 participants, 23% (n=13) did not miss a training session, 14% (n=8) were unavailable for one to three days, 16% (n=9) were unavailable for four to seven days, 16% (n=9) were unavailable for one to two weeks, 9% (n=5) were unavailable for three to four weeks, and 21% (n=12) were unavailable for more than one month. there were 52 participants who reported the number of days they were unavailable for competitive matches for their first reported injury. of the 52 participants, 29% (n=15) did not miss a competitive match, 8% (n=4) were unavailable for one to three days, 15% (n=8) were unavailable for four to seven days, 19% (n=10) were unavailable for one to two weeks, 8% (n=4) were unavailable for three weeks, and 21% (n=11) were unavailable for more than one month. discussion the prevalence of injury in ringball compared to basketball and netball the prevalence of injury in this study with regard to at least one injury over the last/current season was 80% (n=61) (fig. 1). there were 93 reported injuries amongst 61 injured participants (table 2) of which the most common locations of injuries were the foot/ankle at 36%, followed by the knee at 29% and wrist 9%, respectively. studies conducted by pillay and frantz and ferreira and spamer on netball revealed the prevalence of injuries to the foot/ankle as 38% and 39% respectively.[10, 12] additionally, the injury prevalence to the knee was 27% and 28%, respectively. these studies revealed similar results to this present study of the most common areas of injuries. hampton also reported that the foot/ankle (64%) and knee (15%) were mostly injured while reporting prevalence rates that were markedly different.[13] mckay et al. also reported the ankle (30%) as the most commonly injured area in netball; however, the study reported the hand (21%) as the second most commonly injured area and the knee (18%) as the third most commonly injured area.[8] the studies conducted by andreoli et al. and borowski et al. reporting on injuries sustained in basketball were similar regarding the types of most commonly occurring injuries but varied with respect to the prevalence rates.[8, 9, 14]. the studies demonstrated foot/ankle injuries at a prevalence of 22% and 40%, respectively, and the prevalence of knee injuries at 18% and 15%, respectively. a significant association between injury and not warming up before training (p=0.013) and competitive matches (p=0.044) was found. several studies have demonstrated the benefit of warming up prior to sport participation in reducing injury.[15-17] the limited exposure to warming up in this sample group may have been a contributing factor to the higher injury prevalence observed. this study therefore highlights that coaches and players should pay special attention to warming up before competitive matches and training sessions as a simple and cost-effective strategy that may reduce injury. the mechanisms of injuries the results of this study showed incorrect landing (15%) to be table 1. mechanisms of injury for first reported injury (n=59) mechanism of injury count (n) percentage (%) landing: competitive 9 15 jumping: competitive 5 9 collision: competitive 4 7 defending competitive 4 7 goal shooting: competitive 4 7 other: competitive 4 7 ball throw: competitive 3 5 running/short sprints: competitive 2 3 turning: competitive 2 3 defending: training 2 3 jumping: training 2 3 goal shooting: competitive and training 2 3 landing: competitive and training 2 3 running/short sprints: competitive and training 2 3 running and turning: competitive 2 3 landing and jumping 2 3 landing: training 1 2 defending: competitive and training 1 2 goal shooting: training 1 2 goal shooting: competitive and training 1 2 ball throw and goal shooting 1 2 landing and running/short sprints: competitive and training 1 2 ball throw training, collision training, defending competitive, goal shooting competitive, jumping training, landing training, overexertion competitive and running/short sprints competitive 1 2 collision competitive, jumping competitive and running/ short sprints 1 2 total 59 100 fig. 1. number of injuries sustained in ringball players (n=61) 0 1 2 3 4 >4 0 10 20 30 40 50 number of injuries p e rc e n ta g e original research sajsm vol. 32 no. 1 2020 4 the most common mechanism of injury and jumping (9%) to be the second most common mechanism of injury. basketball can be a more physical game on the court compared to netball and ringball, which provides a possible explanation as to why some of the results may differ, particularly the regard to defensive rebounding. pillay and frantz, hopper et al., and mckay et al., all reported similar results to this present study.[8, 10, 18] the studies reported that landing incorrectly was one of the most common mechanisms of injury. in addition, hopper et al. and mckay et al. both reported that contact with another player (collision) was also one of the commonly reported mechanisms of injury.[8, 18] the similarities of injuries can be explained by the general gameplay that involves repetitive jumping, landing and sudden sprints in basketball, netball and ringball. in order to implement the most effective preventative measures, investigating the exact cause of each player’s pain/injury is necessary. this may require the use of three-dimensional kinematic data, in addition to pain prevalence data related to injury location as highlighted by goosey-tolfrey et al.[19] in obtaining three-dimensional kinematic data, goosey-tolfrey et al. revealed that some players generated greater angular velocity of the wrist at the release of the free throw, whilst others generated greater shoulder flexion angular velocity at the release of the free throw.[19] whilst these findings were related to wheelchair basketball players, the findings concluded that different kinematic strategies may be the basis of the prevalence of pain and injury in sport. it is also important for both coaches and practitioners to identify and address biomechanical errors or deficiencies among athletes to ensure a full recovery or prevent injury.[19] re-examining game technique and rules may also be relevant. severity of injuries a total of 9% of participants (n=5) were unavailable for training for three to four weeks, 21% (n=12) were unavailable for more than one month, 8% (n=4) were unavailable for competitive matches for three to four weeks and 21% (n=11) were unavailable for more than one month. dick et al. reported that 18% of the participants were restricted from activity, i.e. both competitive matches and practices, for more than ten days.[20] this comparison is somewhat different from these authors reporting approach as there is overlap between days and weeks compared between these studies.[20] a further explanation for this difference may be due to the study period and amount of injuries reported.[20] dick et al. performed their study over a 16-year period, hence providing more longitudinal data, whilst the current study was conducted over a three to four month period reporting cross-sectional data. notwithstanding this, these authors’ study table 3. number of days that participants were unavailable during training sessions and competitive matches (n=52) number of days/weeks unavailable none 1-3 days 4-7 days 1-2 weeks 3-4 weeks >1 month number of days unavailable for training due to first injury n 13 8 9 9 5 12 % 23 14 16 16 9 21 number of days unavailable for training due to second injury n 9 0 2 6 3 2 % 41 0 9 27 14 9 number of days unavailable for training due to third injury n 2 0 0 1 1 1 % 40 0 0 20 20 20 number of days unavailable for competitive matches due to first injury n 15 4 8 10 4 11 % 29 8 15 19 8 21 number of days unavailable for competitive matches due to second injury n 6 1 1 6 2 2 % 33 6 6 33 11 11 number of days unavailable for competitive matches due to third injury n 2 0 0 1 1 1 % 40 0 0 20 20 20 n, number of participants; %, percentage of training or match days unavailable table 2. number of training sessions and competitive matches missed in the last season as a result of injury (n=59) number of sessions missed 0 1 2 3 4 >4 training sessions missed last season as a result of first injury n 21 8 9 4 4 13 % 36 14 15 7 7 22 training sessions missed last season as a result of second injury n 11 1 2 2 3 3 % 50 5 9 9 14 14 training sessions missed last season as a result of third injury n 4 1 1 0 0 0 % 67 17 17 0 0 0 competitive matches missed last season as a result of first injury n 19 6 9 7 3 14 % 33 10 16 12 5 24 competitive matches missed last season as a result of second injury n 9 2 3 7 1 2 % 38 8 13 29 4 8 competitive matches missed last season as a result of third injury n 4 0 1 0 0 0 % 80 0 20 0 0 0 n, number of participants; %, percentage of training or match sessions missed original research 5 sajsm vol. 32 no. 1 2020 indicates a need for possible modification of training regimes or protective support during sport performance. for example, sitler et al. reported in their study conducted on united states military academy cadet basketball players that ankle injuries were remarkably reduced by ankle stabilisers.[21] baker proposed that bracing the knee to prevent injury provided little knee joint ligament protection, although the ankle, thumb and elbow joints can be stabilised adequately.[22] barret et al. showed significant differences between ankle sprains and highversus low-top shoes.[23] key findings  a prevalence of at least one injury in ringball players was 80%. the possibility of having a second injury was 33% and a third injury was 9%.  the most common locations injured were the foot/ankle (36%), knee (29%) and wrist (7%).  the main mechanism of injury for the first injury was incorrect landing at 15%, jumping 9%, goal shooting 7%, defending 7%, collision 7% and other mechanisms 7%. strengths of the study according to these authors’ knowledge, this is the first study on the epidemiology of musculoskeletal injuries in ringball players. the study is also the first in south africa to obtain prevalence data of musculoskeletal injuries in ringball. limitations and recommendations the study was limited to one province in south africa and may not be representative of the entire country. external physical factors, such as the court surfaces, individual factors, such as body mass index, as well as environmental factors, such as the season of the year, should be considered as part of the analyses/associations drawn. a larger population size should be included in future studies of the epidemiology of musculoskeletal injuries of ringball players in kwazulu-natal or a study on the ringball players of all provinces in south africa. studies should also investigate the court surfaces and consequent incidences of injuries sustained. more attention could be placed on the knowledge that the ringball players have of healthcare professionals and the role they play with regard to injuries, and the most effective treatment protocols for their injuries. analyses of body composition and other individual measures can be assessed to determine possible associations. conclusion constant evolution of sport, through modifications in applied rules and techniques, as well as through the advent of new sports developing from existing ones, can create a more nuanced injury profile to those commonly identified. the discourse between a sport’s uniqueness/modification and its similarities to other sports warrants the need for a more tailored approach to injury prevention and, as such, an important platform for further research. by documenting the risk factors and injuries sustained in terms of location, severity, mechanism of injury etc., can prevent/reduce further injuries from occurring and better managing these injuries through tailored guidelines and protocols for injury prevention and management specific to the sport. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. acknowledgements: the authors would like to thank mr johan wiggle for assisting with the data collection. author contributions: jd pillay and bn mkhwanazi contributed to the design, preparation and finalisation of the manuscript. j wiggill contributed to the paper by way of his research project, the reporting of which formed the basis from which the manuscript was developed. references 1. summerfield k, white a. 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[doi.org/10.1136/bjsm.2005. 018697] [pmid:15911608] 18. hopper dm, hopper jl, elliott bc. do selected kinanthropometric and performance variables predict injuries in female netball players? j sports sci 1995;13(3):213222. [doi.org/10.1080/02640419508732230] [pmid:7563288] 19. goosey-tolfrey v, butterworth d, morriss c. free throw shooting technique of male wheelchair basketball players. adapt phys activ q 2002;19(2):238-250. [doi.org/10.1123/ apaq.19.2.238] [pmid:28195768] 20. dick r, hertel j, agel j, et al. descriptive epidemiology of collegiate men's basketball injuries: national collegiate athletic association injury surveillance system, 1988-1989 through 2003-2004. j athl train 2007;42(2):194-201. [pmid:17710167] 21. sitler m, ryan j, wheeler b, et al. the efficacy of a semirigid ankle stabilizer to reduce acute ankle injuries in basketball. a randomized clinical study at west point. am j sports med 1994;22(4):454-461. 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[doi.org/10.1177/036354659302100416] [pmid: 8368420] south afr ic an jou r n al of sports medicine sportgeneeskunde j o u r n a l o f t h e s. a . s p o r t s m e d i c i n e a s s o c i a t i o n t y d s k r i f v a n d i e s. a. s p o r t g e n e e s k u n d e v e r e n i g i n g volum e 6 number 4 aug/sept 1991 contents editorial comment drugs in sport erythropoietin .................... 3 overview a philosophy for the treatment of acl instability ......................................................... 4 physiology the achilles tendon: a pilot study to investigate the relationship between calf size and strength and achilles tendon thickness ........................ 11 physiology notes notes on the physiology of muscle contraction .................................................... 18 nutrition methods that can be used for the determining of food intake.................................................... 22 physiotherapy the physiotherapy assessment and treatment of a tennis elbow.................................................... 25 news sasma news ............................................. industry news ............................................. 27 28 national advisory board editor in chief: clive noble associate editors: p rof td noakes dawie van velden advisory board: traumatology: etienne hugo physiotherapy: joyce morton nutrition: mieke faber biokinetics: martin schwellnuss epidemiology: derek yach radiology: john straughan physical education: hannes botha internal medicine: francois r etief international advisory board lyle j micheli associate clinical professor o f orthopaedic surgery boston, usa chester r kyle research director, sports equipment research associates california, usa p rof h c wildor hollmann president des deutschen sportarrtebundes koln, west germany howard j green professor, department o f kinesiology ontario, canada george a brooks professor, department o f physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke associate professor, biology department, university o f colorado colorado, usa graham n smith p hysiologist glasgow, scotland photographs counesty o f the image bank jo u r n a l o f t h e s o u t h a fr ic a n spo rts m e d ic in e a ssocia tion 269 w e s t a v e n u e h e n n o p s m e r e v e r w o e r d b u r g , 0157 t he jo u rn al o f the sa s p o rts m edicine a ssociation is p u b lish ed by m e d p h arm p ublications, 3rd f lo o r n oodhulpliga c e n tre , 204b h f v erw oerd d riv e, r a n d b u rg 2 1 9 4 . po box 1004, c ram er view 2060. t el: (011) 7 8 7 -4 9 8 1 /9 . t he v iew s expressed in th is pub licatio n a re those o f the author* and not necessarily those o f the p ublishers. p r in t e d b y t h e n a t a l w i t n e s s p r in t i n g a n d p u b lis h i n g c o m p a n y ( p t y ) l i d r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the c o m p le te o n e -a -d a y multivitamin an d mineral s u p p le m e n t emvit'keeps you <v>»w * d k o r m o a f t i i m d o d n v 7 c o /1 c u / a n h w m n / \ ^ o i a a a a «madaus pharmaceuticals (pty) ltd. p.o. box 76246, wendywood 2144 keep aheqd w fttf reparil g • ■ g2367 (act 1c 100g contains: aescin 1,0g; aescin sodium poiysulphate (heparinoid) 1,0g; diethylamine salicylate 5,0g. qet up qn4 go with magnesif * s/24/192 cfvmagnesium 1 aspartate hcl 1 229,6mg t f ttr> for magnesium deficiency r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial d r u g s in s p o r t e r y t h r o p o ie t in it is not to have taken part but to win at all costs has become the dictum in sport through­ out the world. unfortunately, to achieve this wining goal, both fair means and foul have been used. fair means excellent training methods, proper diet, proper rest, good psychological motivation, etc. foul in most situations means drugs. in order to keep competition fair, drug testing to prevent athletes from using substances which may be helpful, has becom e the order o f the day. unfortunately the last o f banned substances has become as long as your arm. this has made it both difficult for the athlete as well as his doctor. well known cough mixtures for exam ple are banned sub­ stances. it is therefore im portant for the "clean" sportsman to go to a doctor who is knowledgable about these banned substances. the main problem however, is the sports­ man who is taking drugs to enhance per­ formance. there is a war going on between the crooked athletes and the administrating doctors. w hereas most substances are detectable in the urine within a variable time following intake, there are some drugs which because they are natural to the body are impossible to detect as such except that their levels may be abnorm al. testosterone is one o f these sub­ stances which acts as an anabolic steroid. the anabolic steroids are especially used in strength athletics where anaerobic activity is required. they also play a role in endurance athletics. in endurance athletes the aim is to get as much oxygen as possible to the involved muscles. this essentially means an increase in red blood cells to carry more oxygen to the rest o f the body. physiologically this can be done by attitude training, where low oxygen levels in the atm osphere stimulate the production o f red blood cells. blood doping is a technique which has recently been used. h ere the athlete trans­ fuses him self with his own blood stored some tim e earlier. this is o f course "foul play". m ore recently (1986) synthetic erythro­ poietin has been formulated and used by athletes. erythropoietin is a substance nor­ mally produced by the kidneys which is responsible for the formulation o f red blood cells. it is called epo and is able to raise the haematocrit significantly. it clearly increases the oxygen carrying capacity o f the blood. the problem is it is undetectable in the patient and thus escapes routing detection. the major problem however, is that it causes an increase in blood viscosity which in turn may cause vascular sludging and pos­ sible vascular occlusion. it has been shown to cause an 8% im prove­ ment in maximal aerobic capacity, better than the 5% achieved by blood doping. its effect is also immediate and lasts for 120 days (blood doping 10-15 days). there is a possibility that epo has been the reason for the deaths o f 18 cyclists from holland and belgium since 1987. it is a frightening thought that with increased availability, the death rate may increase in endurance athletes. epo has a very positive role in medicine. it does wonders for the anaem ia o f renal failure and can cause a significant haemato­ crit rise in these patients. these people are not in danger o f sludging, however, which is the real danger with athletes. it is produced in california under the trade name epogen and is banned by the inter­ national olympic committee. it has been used in europe for the last few years and is apparently available on the black market in the usa. it is undetectable and even so only stays in the body for about 24 hours. it has been called "go juice" by those who use it. the tragedy is that despite negative pub­ licity athletes will still use it in the hope o f winning. it looks like we have another problem on our hands! d r clive noble mbbchb, fcs (sa) editor-in-chief -------------------------------------------------- 3 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) overview a philosophy for the treatment of acl instability pj erasmus, parow natural history o f acl deficient knee mcdaniel (corr 172 1983, pg 158-163) evaluated 49 patients, on the average 14 years, after the rupture o f the acl and found the following: weakness 55% giving way 73% 8% once a month or more 30% once a year or more meniscectomy 6 8 % had one or both removed osteoarthritis 10% frank 3 0 % joint space narrowing found that the patient at risk was the: heavy weight varus deformity bony lateral ligament instability meniscectomy weak hamstrings m ary lynch (corr 172 1983 pg 148-154) found that jo in t stability in all planes and, particularly in nearly full extension, is an inte­ gral function o f the intact meniscus. when the integrity o f the meniscus is compromised by associated ligament instability or partial or total removal, these functions are altered. u lti­ mately, failure o f the meniscus leads to pro­ gressive joint degeneration. 261 patients with acl tears were evaluated. there was a 98% chance o f a meniscal tear in untreated acl tears within one year o f injury. the incidence was decreased to 48 % by primary reconstruction. bilateral meniscectomies in­ creased the anterior instability 18 times. after partial or total meniscectomy there was a 22% greater incidence o f fairbank's changes than in the control group and 2 times greater incidence than in the mensical sutured group. there was no better joint surface preservation with partial than with total meniscectomy. recent work by freddi fu e ta l (57th meeting aaos) suggests the following: • total meniscectomy results in a 235% increase in contact stresses. • contact stresses after partial menis­ cectomy increase to the proportion o f the meniscus removed. • removal o f the posterior horn leads to stresses o f nearly the same degree as of total meniscectomy especially with the knee in flexion. mechanism of degeneration in acl deficient knee dejour (fjos vol 1 no 2 1987, pg 85-97) evaluated 214 patients with acl deficient knees, on average 13 years after their original injury and suggests the following mechanism for degeneration secondary to a acl insuffi­ ciency. found that with a deficient acl there is at least 6 mm anterior displacement o f the tibia on the femur in the one legged stance and that this leads to an increased load on especially the posterior aspect o f the medial tibial plateau. after a medial meniscectomy the anterior displacement o f the tibia increases to at least 12 mm which results in an even bigger load on the posterior aspect o f the tibia. in addition, the absence o f the medial meniscus increases the load o f the whole medial compartment by at least 30%. 4 --------------------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) overview recurrent antero lateral sub­ luxation (pivot shift) leads to me niscal tears and stress fractures o f the articular surface o f the femoral condyles and is often the reason for the sportsman seeking medical advice as it interferes with his sporting ability and leads to a symptomatic painful knee. dejour however, believes that it is rather the chronic anterior dis­ placement (lachman), which is increased by the loss o f the medial meniscus, than the antero lateral subluxation (pivot shift) which causes medial compartment os­ teoarthritis. this means that if the antero lateral subluxation (pivot shift) is eliminated without elim i­ nating the anterior displacement (lachman) the patient will be able to go back to sport but the progres­ sive medial compartment osteo­ arthritis will not be halted. the overload on the posterior aspect o f the medial plateau results in a distinct radiological medial compartment osteo arthritis con­ sisting of: • osteophytes in the inter condy­ lar notch; • osteophytes on the posterior aspect o f the medial tibial pla­ teau; • narrowing o f the medial joint lips; • posterior subluxation o f the medial femoral condyle seen on a lateral standing view. in treating the acl deficient knee our aim should be: 1. saving the menisci; 2. eliminating the anterior dis­ placement; 3. eliminating the antero lateral subluxation. in s o f t ti s s u e i n j u r i e s .. . froben1 0 0 h e l p s r e s t o r e e a r l y p a t i e n t m o b ility # convenient 15 tablet, 5 day action pack # suitable for competitive sportsmen and women # effectively relieves pain # effectively relieves swelling # peripheral action avoids injury abuse in sport rx froben 100 t.d.s. also available in suppositories. boots wsp pharmaceuticals(pty) ltd 4 0 electron avenue, isando 16 0 0 your gam e plan against pain give them a sporting chance again st pain r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) overview t h e p a t ie n t a t r is k considering what has already been said about the natural history o f the acl deficient knee and the mechanism o f medial compartment osteo arthritis it seems that the following patients are especially at risk and should be treated surgically: • young active sportsmen; • heavily build patients; • already established meniscal injury; • varus deformity this deformity can either be o f bony origin or can be secondary to lateral ligamentous laxity. what should be reconstructed? it is clear that both the pivot shift and the lachman signs should be eliminated by surgery if we wish to obtain a longterm satisfactory result. jakob (jbjs vol 69b no 1 1987, pg 294 299) suggests grading the pivot shift, and this can be used as a guide to which surgical proce­ dure should be perform ed. (see table 1). i would not suggest a specific procedure for repairing this instability but i am just mention­ ing a few o f the more common procedures. lateral extra articular ilio tibial bank (m clntosh/lem aire/a ndrew s/ muller) can be used or possibly biceps tendon. table 1 grade 1: pivot shift + int rotation neutral lateral extra ext rotation 1 lachman < 9 mm articular repair grade 2: pivot shift + int rotation lateral extra + neutral articular repair ext rotation plus central lachman 10-15 mm repair grade 3: pivot shift + ant rotation lateral extra + neutral articular repair + ext rotation central repair lachman > 15 mm medial extra articular repair table 2 tissues available strength (n) width(mm) anterior cruciate ligament 1 7 2 5 ± 2 6 9 n.a. bone-patellar tendon-bone central 1/3 2 9 0 0 ± 2 6 0 1 3 ,8 ± 1 ,4 medial 1/3 2 7 3 4 ± 2 9 8 1 4 ,9 ± 1,1 semitendonosus 1 2 1 6 ± 50 fascia lata ( 15 mm) fascia lata (45 mm) 6 2 8 1 8 0 0 ± 35 1 5 ,6 ± 0 ,8 gracilis 8 3 8 ± 3 0 quadriceps-patellar retina culum-patellar tendon, central 2 6 6 ± 7 4 1 6 ,3 ± 3 ,5 meniscus less commonly used t h e fo llo w in g are th e norm al loads in daily activities: a ctivity m aximum force (n) activity m aximum force (n) level walking 2 1 0 ascending ramp 107 ascending stairs 6 7 descending ramp 4 8 5 descending stairs 133 jogging 6 3 0 sitting and rising 1 73 jolting 7 0 0 6 ------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) over view give them a sporting chance again st pain w l m ust not use a technique that will in any way com prom ise the lateral stabilising structures as that will increase the load on the medial compartment. intra articular autogenous table 2 indicates tissue available for autoge-nous grafts and with it their strength in newtons are given. this is data from noyes et al. it should be noted that they do not state what part o f the fascia lata was tested, the distal part o f the fascia lata is much stronger than the proximal part and it would be important to know which part they tested to make a reasonable assessment on the use o f fascia lata or otherwise. it seems that only the patellar tendon (jones/ erikson/ clancy) and the semitendonosus is o f ade­ quate strength. a wide strip o f ilio tibial band or fascia lata might be strong enough but as it com pro­ mises the lateral stabilising struc­ tures, it should probably only be used in rare cases. it should be noted that auto grafts are free grafts which under­ go necrosis, vascular invasion and cellular proliferation. there i s bone to bone healing in cases where bone-patellar tendon-bonegrafts are used. homogenous (allografts) at the moment there is a great interest in this tissue, and the fol­ lowing is a basic summary o f the present situation. the following tissue can be used: • bone/patellar tendon/bone • fascia lata • achilles tendon in s o f t ti s s u e i n j u r i e s .. . froben 1 0 0 h e l p s r e s t o r e e a r l y p a t i e n t m o b ility # convenient 15 tablet, 5 day action pack # suitable for competitive sportsmen and women # effectively relieves pain # effectively relieves swelling # peripheral action avoids injury abuse in sport rx froben 100 t.d.s. also available in suppositories. froben 100 15 ta b le ts k boots ' pharmaceuticals (pty1 ltd 4 0 electron avenue, isondo 16 0 0 your game plan against pain flu rbi pro fen 1 00 m g r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) overview • bone/anterior cruciate/bone stringent donor criteria is necessary to avoid disease transmission such as aids, hepatitis, etc. g rafts can be harvested clean which then need sterilisation by either: • ethylene oxide which tends to cause a synovitis in the joint; or • irradiation, which causes a decrease in the strength. when fresh frozen and then irradiated (2mrad) there is a 25% loss o f strength. when freeze dried and irradiated there is a 75% loss o f strength. g rafts can also be harvested sterile which do not need any further treatment. preservation can either be done by deep freezing (below -70° c) or by freeze-drying. no rejection o f allografts has been reported and they seem to heal and incorporate in the same way as autografts. it seems that if it is possible to obtain tissue that has met with stringent donor criteria and has been harvested sterily and deep freezed, it might be the tissue o f choice to use. on the other hand if the tissue available has been gassed, irradiated or freeze-dried it seems to be o f inferior quality and should not be used. heterogenous/prosthetic materials the problems with prosthetic ligaments as well as augmentation devices can be summarised as follows: • weak ingrowth o f biological tissue in areas o f fixation; • release o f worn particles leading to tissue reaction both intra articularly and in areas o f fixation; and • fatigue and failure with long-term use. as a result o f these mentioned problems the present indication for prosthetic ligaments are only in salvage surgery. as regards augmentation devices there is no conclusive proof that they in fact give superior results to autogenous grafts used without any augmentation and cases have been described where debris from these devices has resulted in intra as well as extra articular tissue reactions. the following few articles make interesting reading: 1. poly propoline lad roth ajsm 16, 3, pg 301-305, 1985. 2. poli ethyline edwald corr 115, pg 213 219, 1976. 3. carbon fibre parsons corr 196, pg 71-76, 1985. 4. prosthetic synovitis kaufman j rheun 12, pg 1066-1074, 1985. 5. arthritis in artificial ligaments kline ajsm 17: 717, 1989. medial extra articular reefing postero medial capsule (houston) or an advancement semi membranosus tendon (tril lat), this seems to be preferable as it is not influenced by the isometric points, which are very difficult to determ ine on the medial side. operative requisites having decided who should be treated and what should be repaired there are certain technical requirements which must be met for a success­ ful reconstruction. proper graft selection strength the graft should be at least as strong or stronger than the acl. from the work o f noyes it seems that o f the autogenous tissue it is only the patellar tendon, a doubled semitendonosus and a wide strip o f fascia lata that can be used for acl reconstruction. joint acceptability this is especially important when using pros­ thetic ligaments o r homogenous, heterogenous grafts. cases o f reactive synovitis to these types 8 ------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) overview g ive them a sporting chance again st pain o f ligaments have been described and it is possible that, in the future, we will see more o f this problem. longterm survival it is important that the recon­ structed ligament should have a reasonable functional survival period. isometric placement definition o f isometry a graft is isometric if it is so posi­ tioned that is maintains constant length and tension throughout passive knee motion. intra articular (odenstein jb js 67a, pg 257-262, 1985) femur. 15 mm ( ± 3 ) anterior from over the top. tibia: 23 mm ( + 4) posterior from the menisco capsular junction angle: with the knee flexed 90° the angle between the femoral shaft and acl is 28 ( ± 4). it seems from the most recent work o f henning and m uller that the anterior edge o f the acl repre­ sents the isometric points. an­ terior from this on the tibia results in tightness in extension and pos­ terior in tightness in flexion. a nterior from this in the femur results in tightness in flexion and posterior in tightness in extension. extra articular (krackow a/sa/ 11, 5, pg 293-302, 1983) lateral femur, best position is ju st proxi­ mal and posterior from the origin o f the lateral ligament on the lateral femoral condyle. tibia: best position specifically in combination with the mentioned femoral sight, is just anterior from g urdey's tubercle. in s o f t ti s s u e i n j u r i e s .. . froben loo h e l p s r e s t o r e e a r l y p a t i e n t m o b ility # convenient 15 tablet, 5 day action pack # suitable for competitive sportsmen and women # effectively relieves pain # effectively relieves swelling # peripheral action avoids injury abuse in sport rx froben loot.d.s. also available in suppositories. b o o t s p h a r m a c e u t ic a l s(pt yl ltd 4 0 electron avenue, isando 1 6 0 0 your gam e plan against pain fl ur bi pr of en 10 0m g r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) overview medial to my knowledge no specific work has been done on the isometric points on the medial side of the tibia/fem ur. we however, know that they would lie on burm ester's curve and has been well described in m uller's book on the knee. {"the knee form, function, ligament recon­ struction" springer verlag 1983). in practice this means that a graft should be so positioned that after placement, the knee should be able to move passively through a full range o f movement without undue laxity or tensioning developing in the graft. the best way to attain this is to test the isometry o f the proposed point o f implantation o f the graft before finally fixing it and then once it has been fixed to again check for tensioning and full range o f movement. fixation fixation should be o f such a nature that imme­ diate guarded post operative mobilisation is possible. it seems that fixation to a bony point is preferable to ligamentous fixation. the ideal is a bone to bone fixation as is achieved with patellar tendon grafts. non absorbable materi­ als should be used and there should be no undue compression o f the ligamentous parts o f the graft as this will lead to pressure necrosis and rupture o f the graft. at present it seems that the best way of fixating bone-tendon-bone grafts is by the so called interference screw method as has origi­ nally been described by lambert, or by interface fixation where the bony part o f the graft is bigger than the hole in which it is fixated. in tendon grafts it seems that the best fixation is obtained by using unabsorbable sutures and a so-called "whip" stitch. this can be tied either through bone holes or over a screw or staple. tensioning correct tensioning is im portant to prevent lax grafts which will lead to instability or tight grafts which will either rupture or lead to a permanent jo in t contracture. a tensiometer is o f use but even more practical is to put the joint through a full range of motion after the graft has been fixed and at the same time to test the stability. minimal iatrogenic joint damage the more surgical damage done to the joint and the ligamentous structures the more post operative swelling, scarring and osteo arthritis will result. using the arthroscope, meticulous tissue plane dissection, meticulous tissue re­ apposition and hemosthasis all contribute to lessening the surgical damage. post operative requisites early mobilization decreases disuse effect, lessens capsular con tractu res, m aintains articular cartilage nutrition and allows early controlled forces on the graft which has a positive effect on collagen healing. it is clear that wherever possible, one should strive to start mobilising the joint as soon as possible. in studies o 'b rien, wong and friedrich came to the following conclusion: "immediate full ac­ tive motion, quadriceps and hamstring exer­ cises may produce insignificant and safe loads on an isometric acl reconstruction". to achieve this one has to fulfil the already men­ tioned criteria of: • proper graft selection; • isometric placement; • adequate internal fixation; and • correct tensioning. rehabilitation program m e it is essential to have a carefully planned post operative rehabilitation programme. it should be started immediately post operatively and be continued over an approxim ate 9 month period. there should be good liaison between the surgeon, physiotherapist and biokinetist. □ 10 --------------------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiology the achilles tendon: a pilot study to investigate the relationship between calf size and strength and achilles tendon thickness j mitchell, j bowles, n green and d wolff a b str a c t in order to establish normal data for calf size and strength and achilles tendon thickness, 19 young, healthy and physically active males, aged between 18 and 25 years, and with a mean body mass o f 75,2 + 6,1 kg and a mean height o f 1,81 ± 0,04 m, were selected as subjects for this study. c alf size was found to be 36,9 ± 2 , 0 cms (mean ± standard deviation), and calf strength 43 ± 14 kg for 10rm and 67 ± 20 kg for 1rm. achilles tendon thickness was 2,53 ± 0,30 cms (mean ± standard deviation) at the calcaneal insertion, 1,87 ± 0,21 cms at 4 cms above the calcaneus and 2,79 ± 0,33 cms at the musculo­ tendinous junction. the achilles tendon thickness at the calcaneal insertion was significantly sm aller than at the musculo-tendinous junction (t = 2,58; p < 0,01) and greater than at 4 cms above the calcaneus (t = 5,42; p < 0,001). t here was a significant correlation between calf size and strength (r = 0,66), but no significant correlation between calf size and achilles tendon thickness, o r between calf strength and achilles tendon thickness. it is suggested that a large, strong calf and a thin achilles tendon may be predisposing factors for achilles tendon rupture. jeanette m itchell department o f physiotherapy university o f the witwatersrand m edical school 7 york road parktown johannesburg 2193 in t r o d u c t io n there has been an increase in the incidence o f rupture o f the achilles tendon in recent years, which may be associated with the increasing emphasis on sport.1,2 it has been reported that 83,3 % o f cases o f achilles tendon rupture1 occur at the intermediate part o f the tendon (three to five centim etres1 or two to six centimetres3 above the calcaneus), which suggests that this part o f the tendon is the narrowest and therefore the weakest part. furtherm ore, it seems likely that if an individ­ ual has a large calf or a strong calf, and a thin achilles ten­ don, rupture at the narrowest part o f the tendon could occur. no normal values for calf size and strength and for achilles tendon thickness are reported in the current litera­ ture. therefore, this study was designed to establish some nor­ mal data and to determine w hether there is a relationship --------------------------------------- 11 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) • relieves pain • reduces inflammati • restores mobility pan a m ; r m * tu o c s t o{j traum * l e n n o n ^ ^ l l m n i quality medicine you can afford to t (s3) panamor8 -25 enteric c o a te d table t contcrining 25mg dictofenac socfium. reg.no. r/3.1 /49 fs3l pan amor6 at-50 enteric c o a te d table t containing 50mg dictofenac sodium. reg. no. r/3.1/50 [s3] ranamor° -75 iryection. each 3rrrf am poule contains 75mg dictofenac sodtum with 4% v /v benzyl alcohol as preservative. reg. no. 75 m g/3m l ampoules w/3.1/52r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiology between size and strength o f the c alf and achilles tendon thickness. m aterials and methods sample questionnaires were distributed to second-year male medical students at the university o f the w itwatersrand to select ap­ propriate subjects. from this population, 50 male students were found to be suitable in that they had no history o f any ankle injuries, particularly achilles tendon rupture or tendinitis, and were physically active. nineteen o f these students consented to the measurement procedure. the final sample thus consisted o f 19 young, healthy, active males between the ages o f 18 and 25 years, with an average height o f 1,81 ± 0,04 metres (n = 17) and an average body mass o f 75,2 ± 6 , 1 kilograms (n = 17). m ethods of m easurem ent c alf size c alf circum ference was taken as a measure o f calf size. each calf o f each subject was meas­ ured while the subject was seated, with the hip, knee and ankle joints at an angle o f ap­ proxim ately 90 degrees. the broadest circum ference o f the c alf was measured using a standard measuring tape, cali­ brated in centimetres. c alf strength each calf was measured for strength using a standard gymnasium straight-leg-calf induced-heel-raising-resistance apparatus (calf-raising ma­ chine). m easurements were made on each subject in the standing position, with one leg then the other leg straight and weight-bearing, so that each calf was measured separately. a warm-up exercise o f 10 sub maximal heel-raises followed by a one-m inute calf-stretch was given before the tests. a rest period o f two minutes was allowed between the tests. the testing procedure involved, firstly, the 10rm (ten repeti­ tion maximum o r the greatest weight that can be lifted ten times at a normal speed without fatigue o r discom fort) being measured for each calf. sec­ ondly, the 1rm (one repetition maximum o r the greatest weight that can be lifted once at a normal speed without dis­ com fort o r fatigue) was meas­ ured for each calf. achilles tendon thickness the achilles tendon thickness was measured at three points: • at the insertion o f the ten­ don into the calcaneus (ta,); • at a point four centimetres above the calcaneus (ta2); • at the musculo-tendinous junction (ta3). v ernier callipers, calibrated in millimetres, were used, and the subject was seated with the hip, knee and ankle joints at an angle o f approxim ately 90 degrees, the feet supported on a stool. table 1: m ean values of variables (mean ± standard deviation: n = 19) variables left leg right leg both legs p cs 3 6 ,8 ± 2 ,0 cms 3 6 ,9 ± 2 ,0 cms 3 6 ,9 ± 2 ,0 cms ns 10rm 43 ± 14 kg 43 ± 14 kg 43 ± 14 kg ns 1rm 67 ± 20 kg 67 ± 2 0 kg 67 ± 2 0 kg ns ta, 2 ,5 4 ± 0 ,3 0 cms 2 ,5 3 ± 0 ,3 3 cms 2 ,5 3 ± 0 ,3 0 cms ns ta? 1,87 ± 0 ,2 7 cms 1,88 ± 0 ,1 8 cms 1,87 ± 0,21 cms ns ta , 2 ,8 0 ± 0,31 cms 2 ,7 8 ± 0 ,3 8 cms 2 ,7 9 ± 0 ,3 3 cms ns cs = calf size ns = non-significant rm = repetition maximum (calf strength) ta, = achilles tendon thickness at calcaneal insertion ta j = achilles tendon thickness at point 4cm above calcaneus ta a = achilles tendon thickness at musculo-tendinous junction ---------------------------------------------------13 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiology table 2: tests for significance (t tests; n = 19) variables t p 10rm/1rm 4 ,0 9 < 0 ,0 0 1 cs/ta, 7 0 ,4 0 < 0 ,0 0 1 c s / t a 2 6 9 ,6 9 < 0 ,0 0 1 csyta3 6 8 ,0 0 < 0 ,0 0 1 t a ,/t a 2 5 ,42 < 0 ,0 0 1 t a , / t a 3 2 ,5 8 < 0 ,0 0 1 t a 2/ t a 3 5 ,7 0 < 0 ,0 0 1 cs = calf size ns = non-significant rm = repetition maximum (calf strength) ta, = achilles tendon thick­ ness at calcaneal inser­ tion ta 2 = achilles tendon thick­ ness at point 4cm above calcaneus ta3 = achilles tendon thick­ ness at musculo tendinousjunction all measurements were made by the same researchers, to eliminate any inter-rater vari­ ance. results difference between legs on statistical analysis o f the data, it was found that there was no significant difference between the left and the right legs for any o f the m easure­ ments (table 1). c alf size and strength and achilles tendon thickness table 1 shows the mean values for calf size and strength (10rm and 1rm) and for the achilles tendon thickness at the three points o f measurement (the calcaneal insertion; 4 cms table 3: tests for correlation (pearson’ s correlation (r); n = 19) variables r r2 p cs/10rm 0 ,6 6 0 ,4 4 < 0 ,0 1 cs/1rm 0 ,6 6 0 ,4 4 < 0 ,0 1 cs/ta, 0 ,3 0 0 ,0 9 ns c s / t a 2 0 ,3 0 0 ,0 9 ns c s /t a 3 0 ,3 7 0 ,1 4 ns 1orm/ta, 0 ,1 4 0 ,0 2 ns 1orm/ta 0 ,2 4 0 ,0 6 ns 10rm /ta3 -0,2 3 0 ,0 5 ns 1rm/ta, 0,21 0 ,0 4 ns 1 r m / t a 2 0 ,3 0 0 ,0 9 ns 1 r m /t a 3 -0,17 0 ,0 3 ns ta 1/ta 2 0 ,1 6 0 ,0 3 ns ta 1/ta 3 0 ,5 5 0 ,3 0 < 0 ,0 5 t a 2/t a 3 0 ,1 6 0,03 ns body mass 0 ,7 6 0 ,5 8 < 0 ,0 0 1 body mass/1 orm 0 ,7 9 0 ,6 2 < 0 ,0 0 1 body mass/1 rm 0 ,6 6 0 ,4 4 < 0 ,0 1 cs = ns = rm = ta, = t a 2 = t a , = calf size non-significant repetition maximum (calf strength) achilles tendon thickness at calcaneal insertion achilles tendon thickness at point 4 cm above calcaneus achilles tendon thickness at musculo-tendinous junction above the calcaneus, and the musculo-tendinous junction), for the left leg, the right leg and both legs. as expected, the 1rm calf strength was significantly greater than the 10rm strength (table 2). table 2 shows too that the thickness o f the achil­ les tendon varies significantly along its length. at the cal­ caneal insertion, the achilles tendon is thicker than at its in­ termediate part and thinner than at the musculo-tendinous junction. at the musculo­ tendinous junction, the achil­ les tendon is thicker than at its intermediate part (table 1). correlations between calf size, strength and achilles tendon thickness table 3 shows that there is a good correlation between the size and strength o f the calf for both the 10rm and the 1rm. however, table 3 shows too that there is no significant cor­ relation between calf size and achilles tendon thickness at the calcaneal insertion, at the mus­ culo-tendinous junction and at the point 4 cms above the cal­ caneus. there is also no sig­ nificant correlation between calf strength and the achilles tendon thickness at the calca­ neal insertion; at the musculo­ tendinous junction, or at the intermediate part o f the achil­ les tendon (table 3). table 3 shows too that although there is a significant correlation between the achilles tendon thicknesses at the calcaneus and the musculo-tendinous junction, there is no such correlation between either o f these measurements and that at the interme-diate part o f the 14 -------------------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiology tendon. a significant correla­ tion exists between body mass and calf size and strength (table 3), but no such correla­ tion was shown between height and these variables. discussion it is reasonable to suppose that the achilles tendon thickness is related to calf size and strength, and that these variables are re­ lated to an individual's height and body mass. furtherm ore, physiological hypertrophy o f the calf muscles in proportion to physiological needs should produce an increase in the strength o f the calf muscles and hypertrophy o f their ten­ don. the data from this study confirm that the first o f these suppositions is correct. c alf size and strength are signifi­ cantly correlated and are corre­ lated, in turn, with body mass. however, no significant cor­ relation was found between calf size or strength and height. this correlation with body mass is weak, however, with changes in body mass explain­ ing only approximately 50% o f the change in calf size and strength. t h erefo re, other factors such as non-physio logical exercise, for example, must contribute to the variance in calf size and strength. m ore im portantly, the data from this study show that calf size and strength are not asso-ciated with changes in a chilles tendon thickness. m oreover, the thickness o f the achilles tendon varies along its length, with the intermedi­ ate part being the thinnest. these results show that it is possible for an individual to develop a large, strong calf w ith o u t d e v e lo p in g an appropriately thick achilles tendon. this combination o f a strong calf and a thin achilles tendon could result, therefore, in a rupture o f the achilles tendon, at its thinnest, inter­ mediate part, especially if the tendon is placed under ab­ normal tension. conclusions this study has shown that height and body mass do not explain all the changes in calf size and strength. similarly, a significant relationship be­ tween calf size and strength and achilles tendon thickness does not exist in the normal, healthy, physically active young male. furtherm ore, the thickness o f the a chilles tendon varies. therefore, the presence o f a thin achilles tendon and a strong calf muscle may be considered as a predic­ tive factor o f achilles tendon rupture, and such trauma is most likely to occur at the thin­ nest, intermediate part o f the tendon. acknow ledgements this study was approved by the committee for research on human subjects (protocol no. 12/2/90). r e f e r e n c e s 1. j o z s a l , k v istm , b alintb j, reffy a, jarvinen m , letho m and b arzo m. t h e role o f the recreational sport activity in a chilles tendon rupture. a m er j sports m e d , 1989; 17(3): 338-342. 2. n o b lec . t h e p fizer m anual o f sports injuries. vol 1. 1989. p fizer l abora­ tories (pty) l td, sandton. 3. t he lancet. l ancet, 1989; 1: 1427 1428. n [s3j v/3 .1/62, v /3.1/238 w .f.i. h/34/128 tilcotil® components: tenoxicam 20 mg indications: s ym p to m atic treatment of the follow ing painful inflam m atory and degenerative d iso rd ers of the m u scu loskele tal system : rheum atoid arthritis; osteoarthritis; a n ky lo sin g sp o n d y litis; extra a rticular d iso rd e rs, e .g . tendinitis, b u rsitis, periarthritis, gouty arthritis (for tablets). dosage: 20 m g once daily at the sam e time each day. the parenteral form is used for one or two d a ys. for treatment initiation in acute gouty arthritis 40 mg (2 tablets) once daily for two d ays followed by 20 m g once daily for a further five d a ys is recom m ended. contra-indications: known h yp ersen sitivity to the d ru g. patients in w hom salicy la tes or other nonsteroidal anti­ inflam m atory d ru g s (n s a id s ) induce sym p to m s of asthm a, rhinitis or urticaria. patients who are su ffe rin g or have suffered from severe d ise a se s of the upper gastrointestinal tract, in clu d in g ga stritis, ga stric and duodenal ulcer. before anaesthesia or su rg e ry , ‘t il c o t il ’ should not be given to patients at risk of kidney failure, or to patients with in cre ase d risk of bleeding. co n cu rren t treatment with sa licy la te s or other n s a id s sh o u ld be avoided. p re g n a n cy and lactation. precautions: sim u lta n e o u s treatment with a n ticoagu lan ts and/or oral an tidiab etics should be avoided u n le ss the patient can be c lo se ly m onitored. renal function (b u n , creatinine, developm ent of oedem a, w eight g ain , e tc.) should be m onitored, when givin g a n s a id to the elderly or to patients with co n d itio n s that could increase their risk of developing renal failure. packs: t ab lets 20 m g: 1 0 's, 3 0 ’s. vial p ack containing 1 vial active su b sta n ce and 1 am p oule water for injection. --------------------------------------------------15 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) w h e n y o u r p a t i e n t ’s in p a in, y o u r first res p o n s ib ility is t o ta k e a w a y t h a t p a in. q u i c k l y . effectively. b ut d o in g so c ould lead to unacceptable gastro­ intestinal sid e effects a n d c o m b i n a t i o n th e r a p y . b u t n o w , ten ye a rs o f precisely ta r g e te d m o le c u la r research have p r o d u c e d a h ig h ly effective, n o n a c id ic a n t i i n f l a m m a t o r y . relifen. e a c h t a b le t is m a d e o f 500 m g n a b u m e t o n e , a n o n s t e r o i d a l a n ti in f la m m a to p r o v e n in n u m e r o u s d o u b l e blind studies to b effective as o t h e r b e n c h m a r k n s a i d s . yet its r o u t e o f a c tion is tota lly different. relifen is a n o n a c i d ic p r o d r u g . in the s t o m a c h , it is relatively inactive. it is a b s o r b e d f r o m t h e d u o d e n u m , in to t h e p o r ta l b l o o d sup fina lly, in the liver, it is m e ta b o lis e d i n to a p o i n h i b i t o r o f p r o s t a g la n d i n synthesis. r e f e r p a c k a g e i n s e r t f o r full p r e s c r i b i n g i n f o r m a t i o n . f u r t h e r i n f o r m a t i o n is a v a i l a b l e f r o m o u r m e d i c a l d e p a r t m e n t . s m i t h k l i n e b c c c h a m p h a r m a c e u t i c a l s p o b o x 3 4 7 be r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) relieving his pain is pretty sporting of you, old chap. but do you have to get him high on acid? t h e active m e t a b o li te p e n e tr a t e s t h e sy n o v ia l fluid to reach the inflam ed site, givin g effective relief °f s y m p t o m s . e x c r e t io n is b y t h e k id n e y s , so g a s tr o ■ntestinal d a m a g e t h r o u g h biliary re c irc u l a t i o n and reflux is unlikely. f o r effective relief f ro m pain and inflam m ation, with less c h a n c e o f g a s tr o -i n t e s t in a l d i s c o m f o r t , y o u now have an ideal choice. relifen. rolifc, a n d t h e sb l o ^ o a r c t r a d e m a r k s . r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) f h y s e o l o g y n o t e s notes on the physiology of muscle contraction m frescura muscle can be categorised into three types: skeletal (some­ tim es known as striated muscle on account o f its striated appearance under the light microscope), cardiac and smooth. in this series o f articles, we will be addressing the fundamental question o f how a muscle contracts with reference to skeletal muscle only. we shall commence with an outline o f some o f the gross mechanical properties o f this type o f muscle and then, in order to understand the physiological basis o f muscle contraction we shall progress to a description o f events at the cellular level. skeletal muscle makes up the great mass o f somatic musculature. characteristically, it contracts and fatigues rapidly, does not normally contract without nervous stimulation and is generally under voluntary control. when an individual chooses to flex a m frescura m rc p o box 70 tygerburg 7505 muscle, an electrical signal is transmitted from the brain to the muscle via the nervous system. the membrane sur­ rounding individual muscle cells has electrical properties such that a potential difference exists across this membrane o f magnitude about -90 mv at rest. the potential difference is maintained by a characteris­ tic distribution o f ions. when the electrical signal or nerve impulse arrives at the muscle membrane, there is a transitory reversal o f potential which is the cue for the mechanical event o f muscle contraction. although the mechanical event does not normally occur with­ out the preceding electrical event, the two are physiologi­ cally distinguished. the man­ ner in which mechanical con­ traction is coupled to electrical stimulation is a very involved subject, best dealt with as a separate issue. for the mo­ ment, let's consider some o f the mechanical properties o f muscle that have been investi­ gated by physiologists. contraction physiologists know that if a sufficiently strong single elec­ trical shock is administered to a muscle, the muscle responds with a quick sharp contraction or twitch (figure 1a). if elec­ trical stimulation is admini­ stered in the form o f two shocks in succession, two twitches occur. however, if the time interval between twitches is gradually shor­ tened, the twitches begin to fuse or summate (figure ib). the summated response from two shocks delivered in quick succession gives rise to a smooth contraction o f larger and longer duration than that o f a single twitch (figure 1c). going a step further, if a series o f shocks o f sufficiently high frequency is delivered, the muscle will maintain its con­ traction which is technically known as a tetanus (figure 1d-f). a lower frequency o f stimulation allows the indi­ vidual twitches to be distin­ guished (figure id). n ow in the human body, muscles nor­ mally contract tetanically, i.e. are stimulated by a train o f electric shocks (impulses) from the nervous system delivered at a frequency o f about 15 to 30 shocks per sec­ ond. the contraction lasts just as long as the train o f electrical impulses are fired and that depends on you. by a volun­ tary decision in the brain to 18 ---------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiology notes figure 1: representation o f tracings obtained from stim ulating a skeletal muscle. tim e scale of electrical stimuli show n along horizontal axis. intensity of figure 1 a: a tw itch response from a single stimulus. figure 1c: as for b but w ith a shorter interval between stimuli showing fusion of response (summa­ tion). figure 1e: as for d but w ith shorter intervals between stimuli showing a sustained contraction. muscle contraction show n along vertical axis. figure 1b: the response from tw o stimuli in succes­ sion. figure 1 d: response from a train of electrical stimuli. figure 1f: as for e but with a shorter interval between stimuli leading to a smooth tetanus. ---------------------------------------19 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiology notes figure 2: diagrams to illustrate m otor units w ithin each of tw o muscles. figure 2a: each motor unit consists of a motor neuron and tw o muscle fibres. figure 2b: each motor unit consists of a motor neuron and five muscle fibres. in reality, the number of fibres associated with each motor unit would be larger but is reduced in the diagram for simplicity. stop the muscle contracting, the train o f electrical impulses is "switched o f f . fatigue what happens if the train o f electrical shocks inducing a contraction persists? a tetanic contraction cannot go on in­ definitely and if stimulation continues for long periods, the muscular response declines and eventually disappears altogether. the muscle be­ comes fatigued. there are several factors that bring this about, one o f which is exhaustion o f energy reserves within the muscle. this leads to a build up o f lactic acid which is toxic to the muscle tissue. fortunately, w e experience this in terms o f pain in our muscles after pro­ longed muscle exercise and so our brain tells us to "stop" contracting the muscle, i.e. "switch o f f the train o f electri­ cal impulses. control o f total m uscle tension and fatigue the greater the frequency o f stimulation the greater the intensity o f the mechanical response until a frequency is reached beyond which the response no longer increases (figure if). this is the grea­ test tension the muscle can develop. the total tension a muscle can develop depends upon two factors: • the amount o f tension developed by each con­ tracting fibre in a muscle; and • the number o f muscle fibres stimulated in the contract­ ing muscle at any given time. the first o f these factors de­ pends on the frequency with which each fibre is stimulated, leading to summation and tetanus. it also depends on some aspects o f the struc­ ture and dimensions o f the components o f a muscle fibre which we will consider at a later date. the second o f these factors can also vary in two ways depending on the number o f motor neurons activated and the number o f muscle fibres associated with each o f them. look at figure 2a and b. a single motor neuron stimulates a specific number o f muscle fibres. this arrangement, namely, a motor neuron and the fibres it innervates, is called a motor unit which may be small or large depending on the number o f fibres associated with the neuron (two and five respectively in figures 1a and ib). a muscle is composed o f many such units. as the num20 ---------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physhology notes ber o f motor units receiving electrical stimulation goes up, so does the intensity o f the contraction. in addition, the number o f muscle fibres asso­ ciated with a single motor unit varies considerably in dif­ ferent types o f muscle. in muscles such as those o f the hand and eye, which are able to produce very delicate move­ ments, the size o f the individ­ ual motor units is small (in an eye muscle, one motor neuron innervates about ten muscles fibres only). by contrast, in the more coarsely controlled muscles o f the back and legs, each motor unit contains hun­ dreds o f muscle fibres (a single motor unit in the large gastrocnemius calf muscle contains closer to one thou­ sand seven hundred muscle fibres). if a muscle fibre is composed o f small motor units, the total tension produced by the muscle can be increased in small steps by the recruit­ ment o f additional motor units, whereas if the motor units are large, a greater jump in tension occurs as each addi­ tional motor unit is recruited. muscles with small motor units then, allow finer control o f muscle tension. and the total tension a muscle deve­ lops can vary according to the number o f fibres associated with each motor unit. an interesting way o f over­ coming the fatigue that might result from prolonged continu­ ous activity in some muscles is for motor neurons to fire synchronously. thus, some motor units may be active while other motor units are momen­ tarily inactive or, if you like, resting. in muscles which are active for long periods o f time, e.g . postural muscles which support the weight o f the body, this synchronous activity helps prevent fatigue while main­ taining an almost constant tension. in the next article we shall look at the ultrastructure and explore some o f the events involved in muscle contraction at the level o f an individual muscle fibre. □ i c a t i o n f o ra p p r e s e a r c h grant to p ro m o te k n o w le d g e a b o u t th e role o f sugar in h e a lth a n d nutrition, th e south a fric a n sugar a ssociation looks to th e s cie n tific c o m m u n ity for re lia b le a n d u p -to -d a te in fo rm atio n. as p a rt o f this process, it supports scie n tific rese arch p ro je cts d e s ig n e d to c la rify issues w h ic h arise in this p u b lic terrain. the sugar a ssociation a c ts o n th e re c o m m e n d a tio n s o f a research a dvisor a n d advisory panel. priorirties for rese arch fu n d in g b y th e a ssociation are; 1. physical w ork, exercise or sport in relatio n to diet. 2. o be sity a n d th e c o m p a ra tiv e role o f d iffe re n t d ie ta ry fa c to rs a n d forms o f exercise. 3. causes o f d e n ta l caries a n d p e rio d o n ta l disease. 4. diet in re la tio n to d ia b e te s mellitus. 5. h yp erlipidae m ias in relatio n to diet. 6. g ly c a tio n o f proteins. proposals in a n y o n e o f the se priorirty fields will b e giv e n c o n sid e ra tio n . the research grants a re a w a rd e d o n a 2 ye a rly basis. c o n tin u a tio n o f th e g ra n t for th e s e c o n d y e a r o f study is d e p e n d e n t o n progress m a d e , as assessed b y th e advisory panel from a re p o rt su b m itte d fo r this purpose. instructions for proposal preparations: in o rd e r to a llo w fo r a p ro p e r e v a lu a tio n o f proposals b y reviewers, th e fo llo w in g items should b e in c lu d e d : 1. o n e p a g e a b s tra c t o f th e p ro p o sa l p ro je c t (200-w ord m a xim u m ) 2. short d e scrip tio n o f b a c k g ro u n d fo r p ro p o s e d p ro je c t research, 3. s o c c in c t s ta te m e n t o f p ro je c t ob je ctives, 4. short d e scrip tio n o f m e th o d s to b e used in pursuing ob je ctive s. 5. c le a ra n c e fo r th e research fro m a n a n im a l or h um an review c o m m itte e if a p p lic a b le . 6. c u rriculum v ita e a n d list o f full-len gth p u b lic a tio n s o v e r th e last six years. 7. d e ta ile d b u d g e t (to in c lu d e th e p ro p o s e d b u d g e t for th e first a n d s e c o n d years o f study). note: no funds a re p ro v id e d fo r m a jo r e q u ip m e n t (unit c o s t g re a te r th a n r2 000) o r tra v e l costs. the d e a d lin e fo r proposals to b e s u b m itte d is 15 n o v e m b e r 1991. a p p lic a tio n form s a re a v a ila b le from a n d , w h e n c o m p le te d , should b e re tu rn e d to: the nutritionist .the south a fric a n sugar a ssociation, po box 374, durban 4000. tel: (031) 305 6161. n e ithe r la te a p p lic a tio n s nor a p p lic a tio n s re c e iv e d b y fa csim ile will b e a c c e p te d . sugar association -------------------------------------- 21 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) n u t r i t i o n methods that can be used for the determining of food intake mieke faber there are at present various methods for the measurement o f the dietary intake o f indi­ viduals and groups. there is no best method for all study purposes. each method has advantages and disadvantages. in general, methods can be divided into 2 basic categories. one category records data at the time o f eating. the second category collects data about the diet in the immediate, re­ cent or distant past.1 the selection o f the method for a dietary survey depends on: • objectives o f the study, e.g. the degree o f accuracy needed and the type o f data needed. • the study population, e.g. the sample size, the co­ operation and ability o f the subjects and the con­ straints on time. • the expertise available, e.g. the skill o f the inter­ viewer. mieke faber research institute f o r nutritional d iseases m edical research council tygerberg • the resources available, e.g. finances.2 the likely response rate and the accuracy o f the method is also important.3 generally, the more accurate the method, the greater the cost, the greater the degree o f respondent co­ operation that is required and the lower the response rate.3 dietary records of present food intake in this method, the respondent keeps a record o f all food and drink consumed. the portion sizes are either weighed, measured or estimated.4 for this method the respondents must be literate, physically able to write, and motivated to keep a detailed diary.5 the advan­ tage o f this method is that it does not rely on memory. it can also provide detailed food and food pattern information. it must however, be kept in mind that there is a decline in the accuracy in recording after a few consecutive days. an­ other disadvantage is that the fact that he must record every­ thing that he consumes might intentionally or unintentionally influence and alter the respon­ dent's dietary intake.6 for example, a respondent might choose to order a sandwich at lunch instead o f choosing a dozen or so items from a salad bar, because the former would be easier to record.7 the seven-day dietary record is impractical for epidemiologic studies since it demands a high degree o f cooperation on the part o f the subjects.4 the dietary record can either be a weighed record or an estimated record. when keeping a weighed record, the respondents weigh and record the food immediately before eating and after the meal the leftovers are weighed. this is thought to be the most accurate method. it requires a higher degree o f cooperation from the respondents than some other methods and this is likely to affect the response.1 with an estimated record the food eaten is recorded in household measures such as spoons and cups. it is simpler and less de­ manding for the respondents than the weighing method. there is less interference with usual dietary practices if the food need not to be weighed. estimated records are poten­ tially well suited for collecting cross-section al d a ta ,1 e s ­ pecially if it is kept in mind that the weighed method and the estimated method gave similar assessments o f mean protein and energy intake.5 in order to classify the nu­ trients into the top or bottom 22 ---------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nujtmmon thirds at 80 per cent reliability it was indicated that for sugar and carbohydrates 2 to 3 days o f record keeping are long enough, whereas for dietary cholesterol and p/s ratio much longer surveys o f 2 to 3 weeks are needed. for most o f the other nutrients a week's sur­ vey appears to be enough.8 it would appear that the period for measuring habitual intake should be 7 days.9 in order to monitor lipid and energy in­ take, 7 consecutive days o f food recording were consid­ ered the minimum requirement for a 95% confidence lim it.10 dietary intake indicated that a one week record was as rep­ resentative as any other week during a 28-day study.11 it can be questioned whether a period longer than seven days should be used since it was found that the validity o f the 7-day dietary record declined during the last few days o f the record period. moreover, respondents keep­ ing records for longer periods tend to be more motivated and better educated than those who drop out.12 thus, i f the recording period is too long, the final sample may not be representative o f the group it is intended to reflect. recall of intake in the past 24-hour recall the respondent is asked to re­ call his intake in the last 24 hours or for the preceding day. food quantities are usually assessed by the use o f house­ hold measures, food models or photographs. the interviewer should be trained in the art o f questioning.1 the main disit should always be kept in mind that each method has its short­ comings. the method most suitable f o r the purpose o f the study should be used. advantages o f this method is its reliance on memory,3 and the fact that due to day to day variation it can only be used for groups.1 when using the 24-hour recall method, some respondents overesti­ mate their usual intake and some underestimate it.5 this method may also be subject to the "flat slope" syndrome. this means that it may overesti­ mate the intakes o f those re­ spondents with a low intake and underestimate the intakes o f those with a high intake.12 this could be o f particular con­ cern in athletes, as different groups o f athletes may have either habitually low or high levels o f food intake.7 the 24 hour recall has been directly validated by comparing re­ called intakes with intakes that were previously observed and unobtrusively recorded by the investigators. mean intakes estimated from these two methods were similar for the group as a whole, indicating that the 24-hour recall is valid for assessing intakes o f groups.12 the 24-hour recall is less costly and less demanding on the subject. the main advantages o f this method is that it is quick and simple to perform and it places a minimal burden on the respondent leading to a high response rate.1 it can yield good infor­ mation about the average dietary intake o f a large popu­ lation, but it is unsatisfactory on the individual level.213 however, it can be used to determine the nutrient intake o f an individual provided that multiple recalls, spaced over a considerable time period, are obtained. the average o f the multiple days may give a good indication o f the individuals in­ take.6 in as early as 1952 young et a l has stated that when an estimate o f the mean intake o f large groups (n > 50) is desired and when some errors o f 10 per cent can be tolerated, the shorter 24-hour recall method can be used in the place o f the more time-con­ suming seven day record. this would mean a saving in time, both in collection o f data and its calculation and analysis. less participants time and co ­ operation is needed, resulting in the possibility o f a more r ep resen ta tiv e p op ulation sample.14 the 24-hour recall can be administered by interview or per telephone. when the 24 hour recall was administered per telephone, it was found that this method produced accep­ table estimates o f the means and distributions o f nutrient intakes among groups o f indi­ viduals. the telephonic 24 hour recall can markedly re­ duce the cost, time, logistical and personnel constraints associated with nutrition sur­ v ey s.15 according to gam et al. (1978) if a cut-off point is used to ascertain the percentage o f subjects at nutritional risk, a -------------------------------------- 23 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m jtm mon higher proportion o f individu­ als will be classified as being at risk using a 1-day nutrient intake as compared to seven days. although 1-day dietary intake methods may be used with confidence in determining the mean intake o f a large enough sample, 1-day dietary intake methods are inappro­ priate in ranking individuals, or in estimating the proportion o f individuals at nutritional risk.16 diet history this method assesses the usual intake over a period o f time such as the past year. as opposed to the food frequency method, portion sizes o f all the foods are given and this method determines the whole diet and not only a few nutri­ ents.6 the diet history method yields higher values than the seven day record413 as well as the 24-hour recall.13 this method gives information on the diet over a long period o f time. the main disadvantage is that it relies on the respon­ dents memory. it also concen­ trates on regular patterns so that irregularities are easily underestimated.1 it also re­ quires that subjects be aware o f their food intake and have well defined eating patterns.7 food frequency questionnaires in this method, the respondent is presented with a list o f foods and asked how often he eats them.6 for estimating usual food intake o f a group, the frequency method appears to be highly successful. this method is however, not recom­ mended to estimate the precise nutrient intake o f individuals.17 this method is cheap and simple.1 analyzing the collected data after the food intake has been determined, it must be con­ verted into nutrient intake. although this can be done by hand, this is a very cumber­ some method. nowadays, nutrient analysis is usually done by computer. for this purpose, various computer programmes are available, either for the pc or for the mainframe. before the food can be analysed, all food con­ sumed must be converted to grammes. there is a south african manual available that assists with the conversion o f food items from household measures to grammes.18 after the food items are converted to grammes, it is analysed by computer in order to obtain the different nutrients. in summary it can be said that when doing a dietary study, it should always be kept in mind that each method has its shortcomings. the method most suitable for the purpose o f the study should be used. references 1. cameron me and van staverenw a. m anual on methodology fo r fo o d consumption studies, 1988. oxford university press: oxford. 2. karkeck jm . improving the use o f dietary survey methodology. j am diet assoc, 1987; 87: 869-871. 3. fehily a m . epidemiology for nutri­ tionist: 4 survey methods. hum nutr: a ppl nutr, 1983; 37a: 419 425. 4. block g. a review o f validation o f dietary assessment methods. am j epidmiol, 1982; 115: 492-505. 5. todd ks, hudes m and calloway dh. food intake measurement: problems and approaches. am j clin nutr, 1983; 37: 139-146. 6. block g. human dietary assess­ ment: methods and issues. prev med, 1989; 18: 653-660. 7. barr si. women, nutrition and exer­ cise: a review o f athletes ’ intake and a discussion o f energy balance in active wom en. prog food nutr sci, 1987; 11: 307-361. 8. m arr jw and heady ja. within and between-person variation in dietary surveys: number o f days needed to classify individuals. hum nutr: a ppl nutr, 1986; 40a: 347 364. 9. acheson kj, campbell it, edholm og, m iller ds and stock mj. the measurement o f food and energy intake in man an elevation o f some techniques. am j clin nutr, 1980; 33: 1147-1154. 10. jackson b, dujovne ca, decoursey s, beyer p, brown ef and has sanein k. methods to assess relative reliability o f diet records: minimum records for monitoring lipid and caloric intake. j am diet assoc, 1986; 86 : 1531-1535. 11. st jeor st, guthrie ha and jones mb. variability in nutrient intake in a 28-day period. a m j d iet assoc, 1983; 83: 155-162. 12. gersovitz m, madden jp an d wright hs. validity o f the 24-hour recall and seven-day record for group comparisons. am j diet assoc, 1978; 73: 48-55. 13. karvetti r and knuts l. validity o f the 24-hour dietary recall. j am diet assoc, 1985; 85: 1437-1442. 14. young cm , hagan gc, tucker re and foster w d. a comparison o f dietary study methods. dietary his­ tory vs seven-day record vs 24-hour recall. j am diet assoc, 1952; 28: 218-221. 15. posner bm, borman cl, morgan jl , borden ws and ohls jc. the validity o f a telephone-administered 24-hour dietary recall methodology. am j clin nutr, 1982; 36: 546-553. 16. gam s m , larking fa and cole pe. t he real problem with 1-day diet records. am j clin nutr, 1978; 31: 1114-1116. 17. mullen bj, krantzler n j, grivetti le, schutz h and meiselman hl. validity o f a food frequency ques­ tionnaire for the determination o f individual food intake. am j clin nutr, 1984; 39: 136-143. 18. langenhoven m l, conradie pj, gouws e , wolmarans p and van eck m. nr1nd food quantities man­ ual, 1986. south african medical research council, parow. □ 24 ---------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy the physiotherapy assessment and treatment of a tennis elbow joyce morton with wimbledon only recently over, it seems an appropriate time to discuss the physiotherapy ap-proach to a lesion o f the extensors carpi radialis longus and brevis. a tennis player will usually give a history o f a typical over­ use injury. as with all teno periosteal lesions, the older the player, the more prone he is to injury. the injury is caused by faulty stroke technique, too heavy a racquet or too tightly strung a racquet, or an incor­ rect size o f the racquet grip. the result is that the extensor muscles o f the forearm are loaded with a weight which is too heavy for them, they are unable to cope with the stress and micro-trauma takes place. as the player continues to play tennis, any attempted healing by the body breaks down and more micro-trauma takes place. eventually the pain is so severe that the player is often no longer able to grip his racquet, let along play a shot. on examination, the diag­ nosis is confirmed by keeping the elbow extended and ex­ tending the wrist against re­ sistance. pain is felt at the elbow, but may refer along the back o f the forearm as far as the wrist and dorsum o f the hand, or the pain may even refer up the arm. there are three sites which can be the cause o f the pain at the elbow, the most common being the tenoperiosteal origin on the lateral epicondyle. it is this lesion which often responds to a steroid injection and also often responds to physiother­ apy techniques. at least in this case it is comforting to know that if one avenue o f treatment fails, there is another avenue to follow. the physiotherapist treats the injury as follows: after palpating for the pain­ ful area she massages the site with deep transverse frictions using her thumb. this tech­ nique divized by the late dr james cyriax is without doubt one o f the most successful techniques that we use for soft tissue injuries. to begin with, the patient will find the massage exquisitely . painful but as the minutes go by the area becomes numb. dr cyriax advocates that this massage is continued for 15 minutes. it is extremely tiring work for the physiotherapist and i must add that her thumb too becomes numb! s om e p h ysioth erap ists follow this by placing the arm in internal rotation, the fore­ arm in pronation, the elbow in a few degrees o f flexion and the wrist in full flexion. keeping the wrist fully flexed, the physiotherapist snaps the elbow into full extension. this technique is called a mills manipulation. as only a small section o f the tenoperiostial junction is affected, the aim o f the physio­ therapy treatment is to pull apart the two surfaces joined by the painful scar so that the rest o f the tendon may take the strain instead. after a time new fibrous tissue is laid down which is not under tension. the new scar is malleable and pain free when the patient uses his extensors. even mr gd mait­ land, whose teachings most south african physiotherapist follow, agrees that this is the only way to treat a tennis elbow if it is a true tennis elbow. if however there is an elbow joint component and this usually occurs i f the injury has been chronic, then the joint is treated using the techniques that mr maitland advocates and the tenoperiosteal junction is trea­ ted using the techniques ad­ vocated by dr cyriax. the other two sites are ---------------------------------------25 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy either at the body o f the tendon over the head o f the radius or at the origin o f the extensor carpi radialis longus at the supra­ condylar ridge. these two sites respond to m assage swiftly. the bellies o f the extensor muscles may also be injured at the level o f the neck o f the radius. the area is palpated by squeezing the bellies be­ tween finger and thumb, not by pressing the bellies against the radius as this is normally tender and would give a false diagnosis. m assage does not really help with this injury but a steroid injection does. the mistake that a player now makes is that because it is now symptom free he rushes back to tennis. the muscle has been injured, thus it is weak­ ened. as with all muscle in­ juries, one does not return to sport until the muscle is strengthened. a program m e o f graded exercises is given starting with isometric trai­ ning. as there is no movement o f the jo in t only the muscle is being loaded. the exercise is done at each 20 degrees star­ ting from full flexion o f the elbow to full extension. each contraction is held for 10 sec­ onds. pain is the guiding factor as one does not want to start the whole cycle again by cau­ sing m icro-traum a. the patient progresses to lifting a very light load. a m uscle's strength is built up if that muscle is exercised until it is tired. research in the last 18 months has shown that it is the eccentric movement which is the key to strengthening. this means that the weight must be lowered against gravity whilst using the extensors. if the player sits with his wrist extended over the edge o f a table, he can extend and flex his wrist whilst holding the weight. he will then be doing both concentric and eccentric strengthening. the load is increased guided by the fact that there is no pain. stretching o f the muscles once they are warm, must not be forgotten. the muscles run over two joints, therefore to stretch them, the elbow is extended, the wrist flexed and the forearm pronated. the stretch is held for 30 seconds and then during a further 30 seconds slightly more stretch is achieved due to the inverse stretch reflex. when the player returns to his game, it is advisable that he wears a tennis elbow brace o r a heat retainer. heat retain­ ers are becoming more and more popular in this country as they not only keep the area very warm but also act as a proprioceptive stimulus. □ first analgesia is produced by deep massage. m ill's manipulation may succeed at the epicondyle should injection fa il, but the procedure is valueless unless the patient's wrist is fix e d in fu lle st flexion throughout. 2 6 ----------------------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) news sasma news/sasgv nuus een van die hoofdoelstellings v an d ie s u id a f r ik a a n s e sportgeneeskunde vereniging is om wetenskaplike navorsing op die gebied van sport­ geneeskunde aan te moedig en te publiseer tot voordeel van ons lede en ander persone wat gemoeid is met die versorging en afrigting van sportlui. ten einde ons in staat te stel om hierdie oogm erk te bereik, is daar op die vorige uitvoerende komiteevergadering van die sasgv besluit om die stan daard van ons tydskrif nog verder te verhoog ten einde meer plaaslike en oorsese navorsers aan te moedig om in die joem aal te publiseer. die eerste stap in hierdie rigting is reeds geneem met die aanstelling van die inter nasionale adviserende raad wat saamgestel is uit verskeie sportwetenskaplikes wereld wyd wat ingewillig het om jaarliks 'n bydrae te maak deur artikels aan te bied vir pub likasie, asook om artikels te beoordeel vir publikasie. die feit dat ons tydskrif goedge keur is vir subsidie aan univer s ite ite v ir g e p u b lis e e r d e navorsingsartikels is 'n be langrike motivering vir plaas­ like navorsers wat verbonde is aan tersiere navorsingsen onderrig-instellings. w e have also decided to increase the num ber o f pages in our journal, to accommodate more lengthy articles. in the past the ever increasing esca­ lating cost o f printing and paper was a major constraint in achieving this ideal. w e hope to overcome this hurdle by increasing our a ssociation's membership as well as sub­ scribers to our journal. the association is in great debt to all publishers and advertisers that have made our journal financially viable over the past few years. in turn, we believe that the increased readership o f the journal will be to the benefit o f the advertisers and sport in south africa. by attracting articles from abroad, the journal will also become an international forum for scientists to disseminate research findings m ore widely. south africa has a major role to play in establishing sound principles in the medical care o f our athletes, both in south africa as well as the whole african continent. a reputable journal in this context will be instrumental in achieving our goal. o ur journal is already distributed to the international advisory board, and hopefully we will attract subscribers from overseas. south africa ranks high in the world in the field o f medicine, and sports medicine is no exception. in­ deed, we have something to say! education in sports m edicine and research in the sports sciences are already firmly established in our coun­ try, and there are indications that m ore universities in south africa will establish sports m edicine educational program m es in the near future. m et die verhoging van die wetenskaplike standaard van ons jo em aal, beoog ons nie om ons joem aal se aantreklike voorkom s te verloor nie. dit is ons voom em e om 'n gesonde balans te handhaaf tussen hoogs wetenskaplike en teg nologiese artikels en meer inform ele oorsigartikels wat verstaanbaar is vir 'n groot sektor van ons nie-mediese leserspubliek. dus sal ek voortgaan om die joem aal in volkleur te publiseer. die gewilde kort kolomme insake fisioterapie, voeding en far m akologie, gaan uitgebrei word om ook 'n gereelde sportfisiologie bydrae in te sluit. h ierdie waardevolle bydraes vervul 'n groot leemte in ons opvoedkundige pro­ gram m e wat wetenskaplike feite op verstaanbare wyse oordra aan al ons lesers. dit word geskryf deur kundiges in die onderskeie velde, en ons is hulle baie dank verskuldig vir hierdie groot opoffering wat hulle maak om ten spyte van 'n baie druk professionele pro­ gram nog 'n bydrae te maak tot die suid-afrikaanse sport­ geneeskunde tydskrif. the editorial board o f the south african sports m edicine journal invites our readers and scientists in all related medical fields to submit articles to the e d ito r, d r c live n oble, m edpharm publications, po box 1004, cramerview 2060, or the associate editors: p ro f --------------------------------------------------27 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) news best sports medicine graduate post-graduate students of the n ew sports medicine course at the university of cape t o w n td noakes, sports science centre, university o f cape town, medical school, obser­ vatory 7925, o r d r dp van velden, department o f family m edicine, po box 19063, tygerburg 7505. we envisage that the south african sports m edicine as­ sociation will have to play an increasingly important role in p reparing o u r athletes to participate internationally. we also have to prepare prim ary care physicians to act as team doctors for travelling south african teams to important international sporting contests. sports m edicine has become so specialized, that the days are limited for individual doctors to care for athletes w ith o u t a d e q u a te s p o rts medical training. o ur athletes deserve to be cared for by competent physicians with specialized knowledge in their specific sport. doctors also need to be trained in all aspects o f doping control, and must be adequately equipped to advise athletes on the use and abuse o f medicines in sport. informed doctors will stimulate the trust o f the athletes to reveal their confidential medical problems without the fear that the doctor will break confidentiality by disclosing information without their prior consent. it is in the interest o f all athletes to have access to the best possible medical care, and not to be exploited by scien­ tists, doctors o r coaches. through our journal we wish to keep our sportsmen informed on the new developm ents in the sports m edicine field to help them in a scientific way to m aintain their com petitive edge. □ -------------------------the sports arena is becoming more and more sophisticated and with this, unfortunately, sports injuries are on the in­ crease. to keep abreast o f these developments, the uni­ versity o f cape town has in­ troduced a new post graduate course in sports medicine for medical practitioners. extending over two years, the new course includes regular lectures, workshops, clinical case discussions and sports medicine clinics. a comprehensive research pro­ ject must also be completed. the top student who will graduate with the new ly d e v e lo p e d p o s tg r a d u a te sports m edicine degree from the university o f cape town, will win a prestigious medal and accompanying cash prize as a result o f an annual sponsorship that has been announced by boots pharm a­ ceuticals. this announcement was made at the recent sports m edicine congress at sun city with the aim o f promoting continuing medical education. "we believe sports medicine is a growing science and o f im ­ portance in south africa due to the varied types o f sports injuries that people encoun­ ter," the product manager o f froben said. the accompanying cash prize is granted to the top student to present him /her findings at an overseas con­ gress with the aim o f gaining better exposure and knowledge o f current developments. the first students will g r a d u a te w ith a bsc (m ed)(hons) sports medicine degree at the end o f 1991. -------------- □ -----------------28 — ■ ■ ■ ■ sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nuus female athletes health risks m ale and female athletes generally develop sim ilar training related injuries but despite the equality o f the sexes, women are more prone to horm one and diet-related complications. in her paper on problems o f high p e rfo rm a n c e fem ale athletes presented at the iv south african sports m edicine association congress in sun city in april, guest speaker professor m oira o 'b rien o f dublin, said that a detailed record o f the athlete's men­ strual cycle was vital to pre­ vent the onset o f musculoskel­ etal problems. these problems are more common in female athletes who are amenorrheic. skeletal problems are also associated commonly with late menarche, particularly in single sided sports such as tennis and top level swimming. p ro f o 'brien who is the director o f the human per­ formance laboratory at trinity college, said amenorrhoea should be investigated as osteoporosis could occur due to deficient oestrogen production, even in 20 year old female athletes. "if the low levels o f oestrogen are untreated, it will increase the risk o f fractures and osteoporosis at the meno­ pause", she said. p ro f o 'brien suggests that female athletes who develop recurrent shin splints o r stress fra c tu re s sh o u ld h av e a biomechanical assessment as well as a full horm one profile, a dietary analysis, and bone mineral density assessed. she pointed out that while moderate exercise protected women against osteoporosis, excessive exercise might cause the condition. amenorrheic athletes who are hypoestrogenic develop reduced bone mass. p ro f o 'brien said the mean bone density in amenorrheic runners aged 25, was compa­ rable to that o f women aged 50. "if not treated, they are guar­ anteed stress fractures at the menopause", she warned. thrombophob gel “high heparin content” in a clear non-greasy gel brings immediate tissue penetration alleviates pain, bruising and promotes tissue healing. p e r loog h e p a n n 20 000 iu h e x a c h io ro p h e n e o.ig tan laboratories t of tan limited arks street, >, pretoria. licence of nordmark arzneimittel germany. gel: |st] g 1635 (act 101/1965) full details on composition, indications, contra-indicatior side effects and precautions are available on request. ---------------------------------------------------29 sportsgeneeskunde vol. 6 no. 4r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) news osteoporosis is associated with the age o f onset o f train­ ing, intensity and volume o f training, duration o f participa­ tion in training, the type o f sport, diet and stress. in his paper on osteoporosis in exercise, witwatersrand orthopaedic registrar dr robert van der plank, warned that exercise induced amenorrhoea could be fatal. "a woman who exercises to this level loses all the protec­ tive effects o f her own oestro gens and she loses bone at the same rate as a woman who has been oopharectomised", dr van der plank said. where other injuries are concerned, injuries to the ligaments o f the ankle and knee joints are most common in female athletes. the most frequent injuries in high performance athletes can be attributed to overuse, doing too much too quickly, accord­ ing to prof o ’brien. dietary problems occur more frequently in female widespread ignorance about sport drug rules amongst doc­ tors, pharmacists and athletes alike was highlighted at a major sports medicine congress and a number o f legal implications for doctors who did not play by the rules were identified. it became clear from a num­ ber o f speakers at the iv south african sports m edicine association congress in sun city in april that doctors who prescribed drugs banned in athletes, particularly in the so-called feminine sports such as gymnastics and synchroni­ sed swimming. professor o'brien said eat­ ing disorders occurred in 20% o f athletes in sports where leanness was emphasised. in a recent english survey, 40% o f synchronised swimmers were found to be below the recommended level o f nutri­ ents. female athletes are also more likely to be iron deficient. editor's note new on the market is the lunar dpx, a highly efficient dual photon bone densitometer. it is one o f the world's most advanced scan­ ners providing an accurate and precise measurement o f bone mass which leads to the detection o f osteoporosis both early and advanced stages. for more information, please telephone omnimed at (o il) 833-6250. sport could face legal action if the athlete is suspended from competing after positive dop­ ing tests. in his talk on doctors, drugs and sport, dr joe skowno, medical adviser to the iron man triathlon in johannes­ burg, said that doctors could play an important role in ruining a top sportsman's career. "thoughtless prescribing for a minor illness during competitions may be the death knell o f an athlete's career," he said. dr skowno warned that with the onset o f international competition and the increasing number o f sportsmen turning professional, any medical blun­ der would not be taken lightly. doctors who prescribe anabolic steroids to athletes can also be held liable for any serious medical side-effects as it is illegal to prescribe steroids to enhance performance. dr skowno said one o f the reasons for the widespread ignorance o f sport drug rules was the lack o f an up to date and concise list o f banned or ac­ ceptable drugs in sport. two commercial publications will be made available towards the end o f the year with guidelines on drug prescribing in sport. b esid e s acqu irin g the necessary knowledge o f ac­ ceptable drugs in sport, dr skowno feels that the doctor should also play an active role in preventing the use o f ster­ oids and stimulants by athletes. dr tim noakes, who suc­ ceeds dr dawie van velden as president o f the sports medicine association, said doctors, pharmacists and ath­ letes needed to know which drugs were acceptable in sport. "in south africa, 50% o f the athletes caught taking ban­ ned substances took the drugs out o f ignorance for incidental colds and flu. these drugs are often acquired over the counter and not prescribed by a doc­ tor," prof noakes said. he also felt that doctors should discourage athletes from using drugs in sports, par­ ticularly since there was no proof that agents other than doping in sport widespread ignorance amongst doctors 30 --------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m j u s steroids could enhance sport­ ing performance. prof noakes singled out the lack o f a unified approach to the control o f drugs in sport in south africa as one o f the key problems. he said it was cur­ rently up to the administrators o f the various sports to decide how vigorously they wanted to pursue the issue. "the uncertainty o f the fu­ ture structure o f sporting bod­ ies in the new south africa makes it very difficult to draw up policies on testing for drugs. many current structures will no longer exist and no one knows who should be talking to whom," prof noakes said. cost is another factor preventing blanket testing in south africa. "ideally tests for steroid abuse should be done throughout the year. this has proved to be effective in brit­ ain, but has pushed up the cost o f testing," prof noajces said. southern transvaal branch of sasma up and running dr joe skowno was recently elected as the chairman o f the southern transvaal branch o f the sasma. one o f the objectives o f the group will be to establish a roster o f emergency sports care personnel in the southern transvaal. the branch plans to train doctors, physio­ therapists, etc., to deal with any emergency that might be encountered during a sporting activity. the idea is to supple­ ment existin g first aid services currently available at m ost large sporting occasions, and not to replace them. any people interested in adding their names to the roster are please to contact dr skowno, po box 68958, bryanston 2021. nabumetone: providing effective, safe therapy for the treatment of sports injuries nabumetone is an effective, well tolerated treatment for sports injuries with comparable or better clinical trial results than it's major competitors. several studies have com­ pared the efficacy and toler­ ance o f nabumetone in this indication with those o f its major competitors. a com­ parative study with naproxen found that nabumetone-treated patients had a better resolu­ tion o f injury swelling, al­ though there was no signifi­ cant difference in overall out­ come between patient groups in this study. another com­ parison between these two drugs found better results in the nabumetone group in terms o f anti-inflammatory action and pain relief. comparative studies with ibuprofen have also found similar or better efficacy with nabumetone. soluble aspirin has been found to be both less effective and less w ell tolerated than nabumetone in patients with sports injuries. in a double blind compara­ tive study, a 2 g initial loading dose o f nabumetone followed by a 1 g at night for seven days was compared with an 800 mg loading dose o f ibuprofen followed by a 400 mg four times daily dose for seven days. ~ one hundred and sixty seven patients were admitted to the study, o f whom 85 patients received nabumetone and 82 patients received ibuprofen. twelve patients withdrew from the study, eight from the nabumetone group and four in the ibuprofen group. patient withdrawals from the n ab u m eton e-treate group were due to lack o f efficacy (1 patients), non-compliance/ lost to follow-up (2 patients), and recovery prior to comple­ tion (5 patients). for the ibuprofen treated group, the withdrawals were due to lack o f efficacy (1 patient), loss to follow-up (1 patient), and re­ covery prior to completion (2 patients). all these patients were included in the efficacy analysis and the results at their last assessment were taken as the final assessment. both treatment groups showed a very highly statisti­ cally significant improvement ( p > 0,001) for all parameters at both the interm ediate and final assessment points. there were no statistically significant differences be­ tween treatment groups for the change in pain, swelling or limitation o f function. nabu­ metone however, was found to cause less adverse reaction (3,7%) vs ibuprofen (6,7%). the most common adverse rea ctio n s recorded w ere ------------------------------------- 31 sportsgeneeskunde vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) news gastrointestinal side effects 2,3% for nabumetone and 4,3% for ibuprofen. in a review o f 986 sports injury patients treated in seven centres o f the uk in both open and comparative studies it was concluded that nabume­ tone is an appropriate choice for the treatm ent o f sports injuries because it combines good clinical efficacy with a low incidence o f side effects e sp e c ially g a stro in te stin a l reactions. references available on request. new africa mercy flight service in response to the growing num ber o f south africans travelling on business or holidaying in africa, europ assistance has launched a new mercy flight service called medstar. "last year we handled 411 emergency repatriation cases from africa, transporting sick and injured individuals by charter lear je t, and we expect the number o f cases to double in the next 18 months", says m unro deysel, gm o f europ assistance. few south africans, used to the first world medical facili­ ties here, are aware o f the lack o f medical care available to them while travelling in a third w orld environment, o r con­ scious o f the risk they are ex­ posed to. almost all african countries suffer from a lack o f foreign exchange and medical skills. qualified doctors are few and overworked, medicine is in short supply and medical equipment is often broken or unavailable. the threat o f contracting diseases like aids is increased by the widespread re-use o f disposable needles. "our advice to fellow south africans who become sick or injured while travelling in africa, is to seek repatriation back to sa as soon as pos­ sible". the new m edstar service is available on request and oper­ ates 24 hours a day from the johannesburg based operations room manned by qualified icu nurses and paramedics. the service is backed by 27 years o f specialised aviation experience, specialist sa doc­ tors on 24 hour standby, and over r2 million worth o f miniaturised hi-tech aviation medical equipment. europ assistance is the la r g e s t tra v e l a s s is ta n c e organisation in the world, operating in 211 countries with full representation in 52 african states. the company can be con­ tacted on (o il) 838-6311. -------------- □ ■ [s3] v/3.1/62, v /3.1/238 w .f.i. h/34/128 tilcotil® com ponents: tenoxicam 20 mg indications: sym p to m atic treatment of the follow ing painful inflam m atory and degenerative d iso rd ers of the m u scu loskeletal system : rheumatoid arthritis: osteoarthritis; a n kylo sin g sp o n d ylitis; extra articular d iso rd e rs, e .g . tendinitis, b u rsitis, periarthritis, gouty arthritis (fo r tablets). dosage: 20 m g once daily at the sam e time each day. the parenteral form is used for one or two d a ys. for treatment initiation in acute gouty arthritis 4 0 m g (2 tablets) once daily for two d ays followed by 20 mg once daily for a further five d ays is recom m ended. contra-indications: known h yp ersen sitivity to the drug. patients in w hom salicy la te s or other nonsteroidal anti­ inflam m atory d ru g s (n s a id s ) induce s ym p to m s of asthm a, rhinitis or urticaria. patients who are suffering or have suffered from severe d ise a se s of the upper gastrointestinal tract, including ga stritis, g a stric and duodenal ulcer. before anaesthesia or su rg e ry , 't il c o t il ' sh ou ld not be given to patients at risk of kidney failure, or to patients with increased risk of bleeding. concurrent treatm ent with salicyla tes or other n s a id s should be avoided. p re gn a n cy and lactation. precautions: sim u lta n e o u s treatm ent with anticoagu lan ts and/or oral antidiabetics should be avoided u n le ss the patient can be clo se ly m onitored. renal function (b u n , creatinine, developm ent of oedem a, weight gain , e tc.) should be m onitored, when givin g a n s a id to the elderly or to patients with conditio ns that could increase their risk of developing renal failure. packs: tab lets 20 m g: 10 ’s, 3 0 ’s. vial pack containing 1 vial active su b stan ce and 1 am poule water for injection. 3 2 -------------------------------------------sports medicine vol. 6 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license an evaluation of bicycle-specific agility and reaction times in mountain bikers and road cyclists k buchholtz,1,2 mphil sports physiotherapy, t l burgess,3,4 phd exercise science, mhsc bioethics, bsc physiotherapy 1 department of physiotherapy, lunex university, luxembourg 2 division of exercise science and sports medicine, faculty of health sciences, university of cape town 3 division of physiotherapy, faculty of health sciences, university of cape town 4 centre for medical ethics and law, faculty of medicine and health sciences, stellenbosch university, cape town, south africa corresponding author: k buchholtz (kim.buchholtz@lunexuniversity.net) cycling is a popular recreational and competitive sport for people of all ages and has seen increases in participation worldwide. johnson et al. identified an 11% increase in the cycling population of australia from 2001 to 2007, and similar general trends have been observed in the united states of america and europe [1]. in south africa, there are over 16 000 members registered with the pedal power association, an association for recreational cyclists. there are many health benefits to cycling whether as a sport for leisure, or as a means of transport. these benefits include improved cardiovascular endurance, greater muscle fitness, improved bone health, prevention of weight gain, and a lower risk of heart disease, stroke and high blood pressure [2]. despite all these benefits, cycling poses an injury risk due to its physical nature and exposure to external factors such as vehicles and obstacles [3]. aleman and meyers estimate that 85% of cyclists are injured during the cycling season in both mountain and road cycling [4]. the most common mechanisms of acute injury in mountain biking are falls related to a loss of control of the bicycle, while road cyclists report collisions with other vehicles and bicycles [1,4]. cycling takes place in dynamic environments, thus there are several factors which are related to the risk of injury. excessive fatigue, low level of cycling experience, inappropriate or improperly adjusted equipment, terrain, and conditioning and fitness levels are all factors that may increase a cyclist's injury risk [4]. one of these factors is reaction time (rt) [1]. johnson et al. found a significant association between cyclist rt, a post-event (post-collision or near collision with car) manoeuver, and the severity of this incident between cyclists and car drivers [1]. there are multiple types of rt, including simple, choice and discrimination. simple rt is a single response to a single stimulus, and choice rt is a correct response to multiple random stimuli [5]. discriminatory or recognition rt is a correct response to multiple stimuli after determining whether a response is appropriate [5]. reaction time is affected by age, sex, physical activity and fatigue [6]. previous studies have investigated the associations between reaction time and other variables during sport. moradi and esmaeilzadeh assessed speed, agility and reaction time and found that agility in schoolboys correlates with quicker rt [7]. intensity of the physical activity or the level of cognitive ‘arousal’ has also been linked to a faster rt [5]. skilled sportspersons have better cognitive function and quicker rt during submaximal physical activity [8]. however, there is limited literature on reaction time and agility in cycling specifically, which warrants further investigation. the aim of this study was to evaluate bicycle-specific agility and reaction times in mountain bikers and road cyclists at different intensities of cycling. methods study design this is a descriptive cross-sectional study. participants thirty-five healthy male and female mountain bikers and road cyclists aged 18 to 69 years, who cycled a minimum of four background: cycling is a popular recreational and competitive sport with many health benefits but also significant risks, with 85% of recreational cyclists reporting an injury each season. the most common mechanism of injury is through a loss of control of the bicycle, and collisions with other objects. reaction time and agility in cyclists may contribute to the ability to control a bicycle. objectives: to evaluate bicycle-specific agility and reaction time in cyclists. methods: the study was a cross-sectional observational study. thirty-five cyclists (27 males, eight females) participated in this study. participants attended a single testing session where they completed a bicycle-specific agility test, and online simple and choice reaction time testing while cycling at three different exercise intensities. results: there was a significant difference in agility between males and females (p=0.01). there was also a significant difference in choice reaction time between cycling at ‘light’ and ‘very hard’ intensities (p=0.004), and a significant positive relationship between agility and simple reaction time at a ‘hard’ intensity. discussion: choice reaction time improved at ‘very hard’ cycling intensity, supporting the theory that increased exercise intensity improves cognitive arousal. this reaction time may be essential as a means to avoid collisions and falls from bicycles. bicycle-specific agility appears to be related to simple reaction time, but there are no existing validated bicycle-specific agility tests available. the value of the tests undertaken by the authors needs to be assessed further. conclusion: choice reaction time was significantly decreased in high intensity cycling compared to cycling at low intensities. further prospective studies are needed to establish links between reaction times and bicycle-specific agility. keywords: exercise intensity, performance, bicycling s afr j sports med 2020;32:1-5. doi: 10.17159/2078-516x/2020/v32i1a8576 mailto:kim.buchholtz@lunex-%20university.net http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8576 https://orcid.org/0000-0001-9796-2182 https://orcid.org/0000-0002-1976-345x original research sajsm vol. 32 no. 1 2020 2 hours per week over the past six months were recruited for this study. participants were excluded if they reported any musculoskeletal injury in the six weeks prior to the study, or if they were considered to be high risk for physical activity on the physical activity readiness questionnaire (par-q) [9]. ethical considerations this study was approved by the human research ethics committee of the faculty of health sciences, university of cape town (hrec ref: 210/2017). the study adhered to the ethical principles outlined by the declaration of helsinki (fortaleza, brazil, 2013). procedure participants attended a single testing session at the sports science institute of south africa, cape town. prior to inclusion in the study, they completed an informed consent form and the par-q to assess for risk of adverse effects from physical activity [9]. once accepted into the study, the participants completed a self-developed questionnaire to assess their demographic and training history. the questionnaire was assessed before use in this study by a panel of experts for construct and content validity. visual acuity was screened using a snellen visual acuity chart to ensure sufficient vision to complete the testing. body mass (kg), stature (m) and waist circumference (cm) were recorded, and body mass index (bmi) was calculated as kg/m2. a modified illinois agility test (iat) was used to assess bicycle-specific agility (fig. 1) [10]. participants were instructed to cycle around cones on the floor as laid out in fig. 1, as quickly as possible. the time was recorded in seconds. the test was terminated if participants stopped at any point during the test to regain balance, or if they placed a foot on the ground. participants were allowed two practice runs of the test to ensure familiarity with the test. participants completed the test three times, and the fastest time was recorded for analysis. reaction time was assessed at different intensities of exercise using a protocol previously described by delignières et al. [8]. the reaction time tests were conducted using an online programme (eyegym) created by dr sherylle calder to measure simple rt (srt) and choice rt (crt) through visual stimuli [11]. in these tests, participants responded to an image appearing on a screen (fig. 2). in the simple reaction time task, the participant responded as quickly as possible to a single item appearing on the screen. for choice reaction time, the participant would have multiple images on the screen but responded only to a single image, ignoring all the others. the reliability and validity of this online programme has not been previously established but is similar to the study by delignières et al. who used joysticks to react to a stimulus on a computer screen [8]. reaction time was assessed with participants cycling on a wattbike (wattbike ltd, nottingham, united kingdom) stationary trainer. the wattbike was set up based on each individual participant’s height and comfort. a laptop was placed at eye level in front of the wattbike and a keyboard placed on the handlebars. participants were instructed to cycle at three different intensities using the modified borg scale to determine the intensities. participants warmed up for five minutes at an rpe of six (‘very, very light’ intensity). simple rt and crt were assessed at rpe levels of 11 (‘fairly light’), 15 (‘hard’) and 18 (‘very hard’). participants cycled at each level for 10 minutes. simple rt and crt were assessed for five minutes into each level of intensity. participants completed three srt and crt tests at each intensity, and the fastest srt and crt were recorded. cadence and wattage were monitored during the test as an indication of effort between stages, but not used in analysis as the wattbikes were not regularly calibrated. statistical analysis descriptive statistical analyses were performed on the anthropometric data. shapiro-wilkes tests were performed for normality. agility and reaction time results were found to be not normally distributed, and non-parametric tests were performed on these variables. t-tests were performed to assess differences between descriptive characteristics in male and female groups. mann-whitney u tests were performed to assess the difference between agility and reaction between male and female cyclists. kruskal-wallis tests were performed to assess differences between the road cycling, mountain biking and both groups. no post-hoc tests were performed as there were no significant results. a friedman’s anova was performed with wilcoxon signed rank test to determine the difference between rt at different intensities of cycling. fig. 1. modified illinois agility test (adapted from raya et al, 2013) [10] fig. 2. screenshot of the reaction time programme original research 3 sajsm vol. 32 no. 1 2020 associations between variables were assessed using a spearman’s correlational analysis. statistical significance was accepted as p < 0.05. results thirty-five participants completed the testing protocol. their descriptive characteristics are reported in table 1. body mass, stature and waist circumference were significantly greater in male participants (p<0.05). the mean years cycled was 21±13 years. the average distance cycled per week was 150±109 km. eight participants were road cyclists (23%), two participants were mountain bikers (6%) and 21 participants cycled in both disciplines (60%). four participants did not complete the questionnaire section on the cycling discipline. individual results for simple and choice reaction time at light, hard and very hard intensities for males and females are presented in fig. 3. there were no significant differences in srt or crt between sexes (table 2). there was a significant difference in agility between males and females (u=46.0, p=0.01) (table 2). there were no significant differences in srt at different intensities of cycling for all participants (table 3); however, there was a significant difference between crt at different intensities (anova chi-sq=10.93, p=0.004). with the use of post-hoc testing, this difference was identified between crt at ‘light’ intensity and ‘very hard’ intensity (z=3.23, p=0.004), but not between ‘light’ and ‘hard’, or ‘hard’ and ‘very hard’ intensities. table 1. descriptive characteristics of male and female participants variable male (n=27) female (n=8) t-value p-value age (years) 44.3±16.8 43.1±14.2 0.16 0.875 body mass (kg) 81.5±14.8 61.4±14.3 3.32 0.0002* stature (cm) 177.5±7.0 163.4±7.3 4.95 0.0002* body mass index (kg/m2) 25.7±3.9 22.9±4.3 1.75 0.089 waist circumference (cm) 87.4±10.1 74.4±8.7 3.20 0.004* data are expressed as mean ± sd. * indicates p<0.05. table 2. results of a mann-whitney u test comparing agility and reaction time scores between male and female participants variable group n median (iqr) sum of u-value p-value agility male 27 29.2 (27.2-32.1) 425 46.0 0.01* female 8 33.7 (32.1-37.0) 206 simple reaction: light intensity male 27 0.37 (0.36-0.40) 451 72.5 0.16 female 8 0.42 (0.37-0.45) 180 simple reaction: hard intensity male 27 0.39 (0.36-0.41) 463 84.5 0.37 female 8 0.42 (0.37-0.44) 168 simple reaction: very hard intensity male 27 0.37 (0.36-0.43) 470 92.0 0.54 female 8 0.41 (0.36-0.45) 160 choice reaction: light intensity male 27 0.47 (0.46-0.52) 477 98.5 0.72 female 8 0.48 (0.46-0.54) 154 choice reaction: hard intensity male 27 0.48 (0.44-0.51) 488 106.5 0.96 female 8 0.48 (0.45-0.51) 143 choice reaction: very hard intensity male 27 0.45 (0.41-0.51) 497 97.0 0.68 female 8 0.44 (0.41-0.50) 133 data are presented as median (interquartile range). * indicates p<0.05. fig. 3. individual results of simple and choice reaction time at light, hard and very hard intensities in males and females original research sajsm vol. 32 no. 1 2020 4 there was significant, but weak positive correlation between bicycle-specific agility and srt at a ‘hard intensity’ (r=0.38, p=0.026). there were no other significant relationships between rt and agility (table 4). discussion sex-related differences in bicycle-specific agility scores were consistent with findings observed using standard illinois agility tests in other studies [12]. agility is a complex task incorporating acceleration, deceleration, change of direction and decision-making [13]. reasons for sex-related differences may include greater muscle mass, greater aerobic capacity and higher anaerobic thresholds as a consequence of genetic and hormonal differences [14]. in this study, the authors did not observe any sex-related differences in srt and crt contrary to the findings in multiple studies as reported by kosinsky [5]. this is most likely due to the small number of females in the study. the authors identified a significant reduction in crt at ‘very high’ levels of cycling intensity compared to ‘light’ intensity. reaction time has been found to improve with intermediate levels of arousal, and to be lower when either too relaxed or too tense in other studies [5]. submaximal levels of physical activity create the optimal arousal levels required for maximal cognitive functioning and potentially, rt [15]. previous research has demonstrated improvements in choice rt for up to eight minutes after exercise [5]. this study identified significant positive relationships between bicycle-specific agility and str at a ‘hard’ intensity. this is supported by moradi and esmaeilzadeh who found significant associations between running agility and srt [7]. bicycle-specific agility differs in that it has an additional piece of equipment with different capabilities in terms of change of direction and which has not as yet been investigated as a valid clinical assessment. limitations during testing, it was noted that the keyboards used for rt testing lacked the sensitivity needed in fast physical testing. the same keyboards were used throughout the study, which may have provided limited potential equipment bias. thus, the results may not be as accurate as required to adequately assess reaction time. the reaction time tests have not been previously validated, and this should be a priority in further research using these tests. the small participant groups when analysing results between males and females and between the types of cycling may have limited the statistical power in these results. conclusion choice rt was significantly improved in response to high intensity cycling compared to the low intensities. quicker srt was related to faster bicycle-specific agility performance. further prospective studies are needed to establish links between reaction times, bicycle-specific agility and control of the bicycle in cyclists. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. acknowledgements: the authors would like to acknowledge the contribution of the undergraduate researchers involved in collecting the data used in this study, namely, louise hichens, sikhonangenkosi (s’kho) ngcobo and samantha rule. author contributions: kb conceived the idea, analysed the data and wrote the final manuscript. tb conceived the idea, assisted with data analysis and reviewing of the manuscript. both authors reviewed the final manuscript before submission. references 1. johnson m, charlton j, oxley j, et al. naturalistic cycling study: identifying risk factors for on-road commuter cyclists. ann adv automot med 2010;54:275–283. 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[doi: 10.2165/11319640-000000000-00000] [pmid: 20020788] table 3. relationship between simple and choice reaction time at light, hard and very hard intensities, with post hoc testing friedman’s anova dunn’s post hoc friedman statistic p-value light vs. hard (z-value) p-value light vs. very hard (z-value) p-value hard vs. very hard (z-value) p-value srt 1.44 0.488 crt 10.93 0.004 1.434 0.455 3.227 0.0038* 1.793 0.219 * indicates p<0.05. srt, simple reaction time; crt, choice reaction time. table 4. correlations between agility and simple and choice reaction time at light, hard and very hard intensities variable r-value p-value simple reaction: light intensity -0.06 0.748 simple reaction: hard intensity 0.38 0.026* simple reaction: very hard intensity 0.31 0.067 choice reaction: light intensity 0.13 0.456 choice reaction: hard intensity 0.33 0.055 choice reaction: very hard intensity 0.27 0.123 * indicates p<0.05. original research 5 sajsm vol. 32 no. 1 2020 5. kosinsky rj. a literature review on reaction time. clemson university, 2013; 4p. available from: https://img.sauf.ca/pictures/2015-0609/a78f336ed69f1bee126e609a30d8349d.pdf 6. ashnagar z, shadmehr a, jalaei s. the effects of acute bout of cycling on auditory & visual reaction times. j bodyw mov ther 2015;19(2):268–272. 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[http://doi.org/10.4314/ajpherd.v15i1.44637] 12. mujika i, santisteban j, impellizzeri fm, et al. fitness determinants of success in men’s and women’s football. j sport sci 2009;27(2):107-114. [http://doi.org/10.1080/02640410802428071] [pmid: 19058090] 13. simonek j, horicka p, hianik j. differences in pre-planned agility and reactive agility performance in sport games. acta gymnica 2016;46(2):68–73. [http://doi.org/10.5507/ag.2016.006] 14. maldonado-martín s, mujika i, padilla s. physiological variables to use in the gender comparison in highly trained runners. j sports med phys fitness 2004;44(1):8–14. [pmid: 15181384] 15. ozyemisci-taskiran o, gunendi z, bolukbasi n, et al.. the effect of a single session submaximal aerobic exercise on premotor fraction of reaction time: an electromyographic study. clin biomech(bristol, avon 2008;23(2):231–235. [doi; 10.1016/j.clinbiomech.2007.08.027] [pmid: 17961893] 16. carmont mr. mountain biking injuries: a review. br med bull2008;85(1):101–112. [doi: 10.1093/bmb/ldn009] [pmid18296453] https://www.researchgate.net/deref/http%3a%2f%2fdx.doi.org%2f10.4314%2fajpherd.v15i1.44637?_sg%5b0%5d=867ommessxkvu1n5nssebvx1n4uunqju9-ltikihhzjen3xqco5u9qzxktzyvlyzwlba-3oiaidewkfoxg_sl_sjcq.piutypsoxia_b-leuqz9zzykwmdfrvmkvr0istdjdlrjqzhxfihhxm_l4ieud3lq9nllyvzz2sqgtuj_l5shag s o u th a f r ic a n jo u r n a l o f ports medicine vol 4 no 4 n o vem b er 1997 mcjgnesft* the first solution for magnesium deficienciesre pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) t o fissr»k l the edge improve bodywork t j r v w v • > * > m w j s t x & j > the multivitamin with extra magnesium that helps the body work. i' madaus pharmaceuticals (pty) ltd reg no.. 77/00174/07 cnr. 16th road & 2nd stieoi halfway house 1685 g n e -a -d a y m ultivitamin and mineral supplement ~ j 0 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial sport psychology special edition it is an cxcittng propsect that this edition o f sajsm is entirely devoted to sports psychology. it marks another m ilestone in sport psychology's developm ent in our country. since south a frica ’s re-entry to international sport, there has been growing interest in the d iscipline by athletes, coa ch es, sports adm inistrators and the m edia alike. judging by the enthusiasm shown by students, there is a sim ilar k eenness to meet the consequent dem ands. w hile this b o d e s well for the future o f south african sport psycholog)', there arc many organisational issues within the d iscipline w hich still need to be a dd ressed. one thing is clear however: a m id st all the academ ic and professional deba tes there is no doubt that the b urgeon ­ ing interest has d evelop ed in response to a need the need to understand and control the diverse influences which p sychological factors have on sports perform ance and the general w ell-being o f athletes. the varied nature o f this need is reflected in the diverse topics and styles evident in this edition. pat scott provid es a theoretical overview o f how p h ysiological and p sychological factors interact to make pain a com plex and often m isunderstood phenom enon. a nderson, bassson, g eils and farman’s article on personality style, m ood states and negative a dd iction , is representative o f a b ody o f research w hich has been included under botli sport and health psychology. it focu ses on the w ell-being o f the general population rather than sim ply the p er­ formance o f elite athletes. in contrast to the theoretical and em pirical based em phasis o f the previous articles, clive b asson ’s case-study p rovides readers with an insight into applied sport psychology. it is a source o f practical ideas for the practition­ er and athlete. finally, o livier looks at p hysiological, kinem atic and p sychological d ifferen ces betw een overground and treadm ill running. w hile psycholog)' is not the main em ph asis, the paper clearly d em onstrates the relevance o f sport p sycholog)' to the other sports s cien ces viz. adding a new dim ension ( in this case the influence o f cognitive appraisal ) to our undertsanding o f con cepts, lessen s the variance w hich is unaccounted for in scien tific research. in light o f the above, sport p svch olog)’ expands sports s cie n ce ’s know ledge of, and ability' to contribute towards the w ell-being and perform ance o f atld etes. should the traditional term “ sh rin k ” then not rather be replaced with “ expander” ... ?! clinton gahwiler guest editor rep̂ nicgel on-the-spot pain relief. [st| reparil®-gel 100 g contains: aescin 1.0 g; diethylamine salicylate 5.0 g. reg. no. g/13.9/2367. byk madaus (pty) ltd. reg. no. 82/11215/07. 2nd road (enr 16th road). randjespark. midrand 1685. sports medicine november 1997 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the s o it ii african journal of sports medicine volume 4 number 4 november 1997 editors p roft d noakes d r mp schivellnits editorial board dr m e moo i la d r p de jager dr j skowno d r p schwartz p ro f r stretch d r c de ridder p r o fb c andrew s dr e w derman mr r h farman dr m mars d r c a noble international a dvisory board lyle j micheli associate clinical professor o f o rthopaedic surgery boston, usa chester r kyle research director, sports equipment research associates california, usa p r o fh c wildor hollmann president d es deutschen sportarztebiuides kohi, west germany h oward j green professor, department o f kinesiology ontario, canada g eorge a brooks professor, department o f physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke associate professor, biology department, university o f c olorado colorado, usa graham n smith physiologist glasgow, scotland contents guest editorial sport psychology c gahwiller concepts in pain mechanisms and management pa scott personality style and mood states associated with a negative addiction to running sj anderson, cj basson, c geils, r farman psychological preparation for a low intensity marathon squash event cj basson 6 12 psychological, kinematic and psychophysical differences between overground and treadmill running 17 s olivier the editor the south african journal o f sports medicine po box 115, newlands 7725 production andrew thomas publishing glenbarr publishers ee private bag x i 4 parklands 2196 tel: (o il) 442-9759 fax: (o il) 880-7898 advertising marika de waal/andrew thomas reproduction output reproduction printing ince the views expressed in individual articles are the personal views o f the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent o f the publishers. 2 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) concepts in pain mechanisms and management pa scott department of human movement studies, rhodes university abstract the challenge to understand the som ewhat nebulous concept o f pain has been around since a ristotle classi­ fied it as the "passion o f the soul", and most a thletes will have experienced pain to a lesser or grea ter degree at som etim e in their career. although there is a clear physiological com ponent as the body responds to som e noxious stimuli, as soon as the pain sensation is ‘felt' it becom es a personalised experience affected by a multitude o f psychosocial fa c ­ tors. the interaction between physiological and psycho­ logical factors results in pain being a com plex multi dimensional phenomenon which is not easily under­ stood. introduction most p eople will experience pain at som e stage hi (heir lives, but no sp ecific group is more likely to experience pain than athletes. c lich es like “ no pain, 110 gain” and “ pain is temporary, pride is forever” arc part o f a drive to push to, and beyon d, a th letes’ phys­ ical lim its. pain has been iden tified as an integral part o f the ath letic experien ce and the phenom enon o f pain is therefore o f great relevance to all involved in sporting activities. john heil o f the united states, p robably one o f the m ost prolific w riters on the psy­ ch ologica l a sp ects o f sport injuries, has identified pain as a “ com p lex m idtidim ensional p hen om en on ” w hich con stitutes an everpresent challenge to the athlete '. the exp erience o f pain a ssociated with phys­ ical perform ance falls into three broad categories: pain as a residt o f traiunatic injury; paul as the result o f excessive physical d em ands; pain suffered during the rehabilitative period as the residt o f one o f the above. as athletes arc pushed to their physical lim its their b o d ie s are under continual stress, the residt being that fatigue, d iscom fort and ‘ real pain’ are c o m ­ mon experien ces. thus an understanding o f the c o n ­ cep t o f pain and its p ossible effects on perform ance warrants system atic investigation. insight into the theoretical background o f the com plexity o f the p h e ­ nomenon o f pain sh oid d help in understanding why athletes respond so differently to painful experiences. concept of pain it is interesting to note that aristotle is reported to have cla ssified pain as the ’’passion o f the sou l” ; som e d efin ed pain as an unpleasant subjective exp e­ rience familiar to everyone, w hile heil* iden tifies pain as “ ... a com p lex biop sych ological p h en om en on ” . the vast array o f d efinition s o f pain, together with varying exp erien ces o f pain, give rise to the question as to w hether pain is a physiological or psychological phenom enon. address for corespondence department of human movement studies rhodes university grahamstown t h e identification o f ‘pain nerves’ in the 19th ce n ­ tury led to the classification o f pain as a sensation and a recognition o f pain as a com p lex p ercept; a c o m ­ bination o f sensation, and affect, not just a sim ple sen sory ex p erien ce m ed ia ted through p eriph eral pathways alone: merskv’ wrote that, “ pain is a m ix­ ture o f sensation and em otion ” . in oth er w ords pain is neither a purely physiological nor purely p sych o­ logical phenom enon, but rather a com p lex interaction o f both dim ensions. however, to gain a full understanding o f this ch a l­ lenging concept it is necessary to first d iscu ss the physiological com pon en ts in isolation before a d d re s s ­ ing the psychological factors to be con sid ered , and finally take an overview’ o f the interaction o f the two. p hysiological factors or the n ociceptive system h eip d escrib es the nociceptive system as a su b-divi­ sion o f the central nervous system w hich together with chem ica l m ed iators is responsible for the sensa­ tion and transm ission o f pain. pain is triggered by the activation o f two identifi­ able types o f receptors, viz the inechanorecep tors and the polym odal n ociceptors. the inechanoreceptors respond to m echanical stim uli (ic external physical p ressure) while the polym odal receptors respond to therm al and chem ica l stiim di and generally have a slow er and longer lasting transm ission, in which the receptors continue to fire for a time after the ce s s a ­ tion o f the pain provoking stim ulus. having been transduced to neural energy,these im pulses then travel along the afferent pathways o f lhc peripheral nerves to the dorsal horn o f the spinal cord w hich, accord in g to h c il’, functions as a sensory nerve “ sw itching station” . here pain, together with other sensory stim uli from the periphery, converge upon com m on sensory neural pathways ascending to the brain. t his is a very sim ilar con cep t to the “ gate co n ­ tr o l” theory w here m elzack and wall*, p rop osed that processin g cen tres within the spinal cord may cith er decrease or increase the intensity’ o f pain as a neuio electrical phenom enon w hich results in the p ercep ­ tion o f relatively lesser or greater pain than that ini­ tially induced. in oth er w ords the pain stim uli are som eh ow m odidated en route to h igher cortical c e n ­ tres. the final p erception o f pain is based upon the sum m ation o f inputs from several areas o f the brain including those responsible for m em ory and em otion. h eip goes on to report that as a con seq uen ce o f this input from various areas o f pain, even at the stage o f initial aw areness, the p erception o f pain gam s som e o f its m eaning from prior experience together with the present state o f m ind o f the athlete. once the experience o f pain has registered, the brain sets o f f a cascade o f electroch em ica l events within the n ociceptive system , and this heightened activity within the neurochem ical system s o f the body will have a d ir e ct influence on the su bsequ en t response to any pain-inducing stim uli. sports medicine november 1997 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) figure 1: a schematic representation o f the multidimen­ sional factors which contribute to the personalised experi­ ence o f pain. (adapted from scott and munton, 1995). however, although pain is recognised as being a physio­ logical response, the intensity o f that response is a p h e­ nomenological experience in that it is very specific to the individual and is greatly influenced by psychological fac­ tors. skulety13 pointed out that while numerous physio­ logical factors give rise to the sensory phenom enon o f pain, psychological components influence the individ­ ual’s reaction to the pain. norris' supports this argument by stating that th e actual ‘feeling’ or being aware o f pain stimuli is about th e same for everyone, but acknowledges that the overall pain experience varies greatly from indi­ vidual to individual. psychological factors heil3 reports that the instant the individual perceives the pain it becom es predominantly a psychological p h e­ nomenon; stating that perception sets o ff a psychologi­ cally driven chain o f reactive events, all o f which result in a personalised response to the pain. fine 1 writes o f pain being a ‘private’ experience and it is a well known fact that people respond very idiosyncratically in pa in (til situ­ ations. the m ost basic reasoning behind this is human variability not only in the innate physical and mental make-up o f individuals, but also their past experience, the present situation in w hich the pain is experienced, and finally a cognitive and affective analysis o f how the pain situation could affect future performances. acknowledging the uniqueness o f individuals, many researches have focused specifically on the personality o f individuals and their response to pain. petrie10 identified different ‘types’ o f people and their response to the expe­ rience o f pain. there are the “ augmentors” w ho appear to exacerbate the intensity o f pain while “ reducers” are those who do not appear to “ feel” pain as much as oth­ ers. others have em phasised the cultural influences and argue that the importance o f the social com ponent in the response to pain has led to the characterisation o f pain as a biopsychosocial phenomenon. the main point here is the importance to recognise the network causality: an athlete’s response to pain will in all probability not depend on any one particular facet, but rather on the interaction o f several personal (both physical and emotional) and social factors. the resulting individual perception o f the pain will clearly affect one’s personal response to the situation. melzack and wall5 in their classic paper on the sub­ ject, talk o f pain as being biologically based with psycho­ logical dimensions. clearly the primary factor must b e physiological in that the noxious stimuli are detected by the sensory pain receptors. however, the affective com ­ ponent is the basis o f the emotional response o f the indi­ vidual, and finally there is the cognitive com ponent which will draw on personal appraisal o f the entire am bi­ ence at the time o f the in jury. pain threshold and pain tolerance t he actual experience o f pain can b e expressed in t wo distinct forms, viz the threshold o f pain and pain tolerance. the threshold o f pain is the level o f stimulus above which pain will b e experienced11 and is an unlearnt, innate physiological response; ie it involves the stimula­ tion o f th e specialised pain receptors and many are now o f the opinion that this pain threshold is very similar for everyone. on the other hand pain tolerance is the indi­ vidual’s endurance o f the pain and is very m uch more a learnt response affected by various psychological factors, specifically the present situation: therefore the tolerance o f pain varies greatly between people. clearly a person’s ability to tolerate pain is extremely important in m ost sporting environments, particularly in endurance type activities. morgan8 reported that the ability to perform successfully in a marathon is governed by the individ­ ual's physiological capacity together with a willingness and capability to endure extreme discom fort and pain. whitmarsh and alderm an15 propose that athletes with higher pain tolerance are likely to perform better than those with low pain tolerance; and heil4 proposes that many o f the greatest sports victories are played out in a field o f pain and injury. another useful conceptual dichotom y in the phenom ­ enon o f pain is that o f acute and chronic pain. simply put the former is short term or im m ediate pain, and the lat­ ter is long lasting pain. but is the temporal factor the only difference? acute pain is generally experienced at the time o f the onset o f trauma. frymoyer and waddell2 state that acute pain usually bears a relatively straight forward relation­ ship to the external cause, the intensify o f the stimulus and tissue damage. they report that acute pain is gener­ ally proportional to the physical finding and usually has a specific location and is easily identifiable. while the dominant com ponent o f acute pain is physical, it is gen­ erally accompanied by the affective state o f anxiety as the athlete worries about the severity o f the in jury this is in contrast to chronic pain which appears to b e more diffuse in nature and is far m ore complex. chronic pain tends to cause continual debilitating discomfort and b ecom e increasingly disassociated from the physical problems; becom ing m ore increasingly associated with emotional distress, depression and a failure to cope. as pain continues, the individual b ecom es preoccupied with the pain and interpersonal functioning is adversely affected. this is com monly m anifested as anger, hostili­ ty and even withdrawal from social contacts. frymoyer and waddle3 warn that chronic pain may b ecom e a pro­ gressively self-sustaining condition, eventually becom ing more psychological than physical. this argument is sup­ ported by heil4, who points out that pain becom es chron­ ic when complaints o f pain b ecom e a way o f expressing distress and when inconsistencies in painful behaviour are noted. assessm ent o f pain due to the com plex and highly subjective nature o f pain it is difficult to gain a tangible, objective assessment o f the amount o f pain being experienced b y the individual. t he sim ple self-report scale o f “ 0 to 10” (see figure 2) is 4 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) versatile and allows pain to b e assessed across a variety o f situations, and is accepted as a valid indicator o f pain intensity. with regular use o f the scale one can gain m ea­ sures o f ‘average training pain’ and ‘worst injury pain’, and so identify specific factors or situations that lead to an increase or decrease in pain. according to heil3 this line o f enquiry and attempt to quantify the level o f pain will in tim e provide insight into the physical challenges the athlete faces in training, com peting and rehabilita­ tion; the training and rehabilitating are o f particular importance as they give one a perspective o f the athlete’s coping mechanism s and how effectively these are work­ ing. pain perceptio n 0. normal 1. 2. uncomfortable 3. 4. very uncomfortable 5. 6. painful 7. 8. very painful 9. 10. extremely painful figure 2: the pain scale. pain management it is not the focus o f this paper to discuss the surgical or pharmacological measures which may b e necessary to repair damaged tissue, but rather the focus is on the per­ sonal management o f pain; in other words the psychologi­ cal coping strategies. weinstein14 wrote o f pain as having a unique unpleasant affective quality, and in order to cope with this experience an athlete has to mobilise special resources. it should b e noted that the experience o f pain is a warning signal and it is important to realise that ‘pain’ is real to the sufferer; no matter how minor the injury appears to be, i f an athlete complains about pain it is indicative that something is wrong. millar7 argues that all pain is felt in the mind even the pain o f a sprained ankle. psychological problems asso­ ciated with the experiences o f pain will hinder athletic per­ formance and should not b e taken lightly. athletes com ­ plaining o f pain must be listened to and appropriate steps must b e taken. there is a need to assess both the physical area as will as possible underlying factors. heil3 proposed a “pain-report attentional matrix” wherein cognisance must b e taken o f the sporting activity, the cause o f the pain, plus the individual. in his conceptual schem e he identifies four broad classes o f pain coping methods. these are defined by whether the athlete “ focuses on” or “ focuses away” from the pain and the activity simultaneously, or, whether there is a separation o f attention between the activity and the pain. the coping strategy selected will depend on the individual, the situation, the activity and the interaction o f these components. a t the tim e o f the occurrence o f an injury the athlete experiences pain, fear and anxiety'. an injured athlete is likely to b ecom e lost in emotional and irrational think­ ing. it is therefore essential to create a sense o f calmness and security by firstly identifying th e site, cause and extent o f injury; then shifting focus from the pain to thoughts o f injury management, rehabilitation and posi­ tive outcome. explain the mechanism s o f injury and the treatment thereof, establish a rehabilitation programme, identifying pain as a routine aspect o f rehabilitation. in other words acknowledge the problem and direct atten­ tion to the solution, keeping the athlete realistically aware o f the situation and involved in the rehabilitative routine. t he emphasis should b e on a safe and speedy return to action. it is also important to help the athlete differentiate between “ acceptable or routine pain” and “ dangerous pain” . the former must b e seen and accepted as ‘normal’ in the training, competing or rehabilitation programme and something which can and must b e tolerated to a cer­ tain degree, while “ dangerous pain” must b e recognised as such and appropriate steps taken to eliminate the cause. conclusion pain is clearly a com plex multi-dimensional phenom e­ non incorporating sensory, affective and cognitive com po­ nents and it is only with a greater understanding o f the general concept plus the individuality o f response to pain that one will b e better able to assist athletes to cope with pain. references 1. fine p g (1 9 9 3 ). the biology o f pain. in j heih psychology o f sport injury. champaign. human kinetics publishers, pp 269-280. 2. frymoyer j w and waddle g (1 9 9 1 ). a cu te and chronic pain in m h pope, gbj andersson, j w frym oyer and d b chaffin ( e d s ) . occupational low back pain assessment, treatment and prevention. st.louis: m oskey year book, pp 71-94. ( 3. heil j (1 9 9 3 ). psychology o f sport injury. champaign, il. human kinetics publication. 4. heil j (1 9 9 5 ). sports medicine injury checklist. sports medicine update, 10(3):16-19. o. melzack r and wall p d (1 9 6 5 ). pain mechanisms: a new theory. science, 150:971-979. 6. mersky h (1 9 7 3 ). the perception and measurement o f pain. journal o f psychosom atic research, 17:251-255. 7. millar a p (1 9 9 5 ). the psychology o f sport. sports medicine update, 10(3):13-15. 8. morgan w p (1 9 8 1 ). psycho-physiology o f s e lf awareness during vigor­ ous physical activity. research quarterly for exercise and sport, 52(3)-.385-427. 9. norris cm (1 9 9 3 ). sports injuries: diagnosis and management fo r phys­ iotherapists. london. butterworth-heinemann. 10. petrie a (1 9 6 7 ). individuality in pain and suffering. chicago: the university o f chicago press. 11. scott pa and mackenzie b (1 9 9 2 ). pain and how workers handle it. safety management, 1(3):1 4-16 . 12. scott pa and munton l (1 9 9 5 ). a th letes’ perception o f pain. paper pre­ sented at 6th south african sports medicine a ssociation congress. durban south africa. 13. skulety fm (1 9 8 4 ). the management o f the chronic pain patient: clini­ cal considerations. j oumal o f orthopaedic and sports physical therapy, 5 ( 6 ) -.305-307. 14. weinstein j (1 9 9 1 ). neurophysiology o f pain. in tg mayer, v mcx>ney and r j gatchel (e d s ): contemporary conservative care fo r painful spinal disorders. philadelphia: lea and febiger, p p 67-73. lo . whitmarsh b g and alderman r b (1 9 9 3 ). the role o f psychological skills training in increasing athletic pain tolerance. the sport psychologist, 7:388-399. q sports medicine november 1997 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) personality style and mood states associated with a negative addiction to running sj anderson msc (clin psych) (natal) cj basson bed. (unisa), ued (natal), ma (psych) (natal). c geils ba (hons), and r farman bphil med (birmingham) abstract personality subtypes and mood states were investigated in addicted and non-addicted runners (n = 4 9 ), and con­ trasted with a control group o f non-exercisers (n = 3 4 ). runners were assigned to a non-addicted and addicted group on the basis o f hailey and b ailey’s negative addiction scale, and all study participants were then asked to complete a biographical questionnaire, the profile o f mood states (poms) and millon clinical multiaxial inventory (m cm i). results revealed a group difference on the vigor subscale o f the poms, while the total mood disturbance score discriminated the non-addicted runners and the non-exercisers. although a trend towards dis­ turbed mood was evident for the addicted runners, this failed to reach statistical significance. the mcmi revealed a number o f group differences in personality subtypes (avoidant, dependent, and schizotypal), as well as for more transient clinical symptomatology (anxiety and d ysthym ia). taken together, the results suggest that high addiction to running is associated with discrete personality and mood profiles that may contribute to diminished health benefits o f running and exercise. the study findings are dis­ cussed with reference to personality theory, and implica­ tions for further research in this area. introduction it is well known that som e athletes engage in intermit­ tent and moderate running, whereas others run with per­ sistent and stubborn regularity. for the latter, running becom es an activity o f central importance in their lives to the exclusion o f all other recreational activity, suggestive o f the properties o f addiction. sachs and pargman,'1 define exercise addiction as: psychological a nd/or physiological dependence upon a regular regimen o f physical activity. additionally exer cise addiction is characterized by recognizable with­ drawal symptoms when the need to exercise remains unfulfilled after 24 36 hours. these withdrawal symp­ toms may encompass both psychological and physio­ logical factors, including feelings o f irritability, tension, guilt, uneasiness, bloatedness, muscle twitching and discomfort (p. 143). various terms are used in the literature to describe this phenomenon, including running addiction, obligatory run­ ning, running dependence, and compulsive running. the origins o f the term running/exercise addiction date back to the late 1960s,2 and have resulted in a distinction being a dd ress for c orrespondence: sj anderson, departm ent o f psychology, university o f natal (pmb), p bag x 01 , scottsville, 3209. tel: (03 31 ) 260-5372 email: andersons@psy.unp.ac.za m ade between positive and negative addiction. this development resulted from a need to emphasise the detri­ mental physical and psychological effects resulting from a dependence on running. the transition from positive to negative addiction has been linked to a time dimension,319 and is described by sachs2 as resulting from running shift­ ing from being an important but well considered aspect o f the runner’s existence, to one that controls the runner's life. the major result is that choices in other important areas o f the individual’s life are eliminated and /o r reduced.' such runners were found to adhere to a regular pattern o f running behaviour and maintain it despite debilitating pain, injuries and medical advice, and in pref­ erence to social, familial or professional responsibilities.2 noakes and colleagues, and d e coverley veale cite cases o f runners with diagnosed myocardial infarction, who ignored severe symptoms while running, and as a result died from myocardial infarcts during marathon events.”0 a further refinement following on the observed relation­ ship between exercise addiction and anorexia nervosa, has been introduced by veale' who distinguishes between primary and secondary exercise addiction. the latter he sees as suggestive o f d ie presence o f an eating disorder, whereas the former he suggests not being related to any discrete mental disorder. etiological explanations have included both physiolog­ ical and psychological perspectives. the former proposes that increases in levels o f plasma b-endorphin released into the central nervous system in response to the stress o f exercise, with subsequent m ood enhancing and anal­ gesic effects, are responsible for the development o f addiction;” 10 however, the findings are equivocal.0 what has not been established, is why only some individuals becom e addicted to running. psychological investigations into the personality characteristics associated with run­ ning and running addiction in general have been conduct ed.2~ 2sai recent overviews o f the relationship between sport and personality have sketched the long history o f dispositional approaches to the study o f this relation sliip.30,3132 this trend has been questioned and the use o f more interactional paradigms has been strongly advocat­ ed.*131 cox is more optimistic especially if use is m ade o f relevant theory as well as multivariate statistical m ethod­ ology such as regression analyses."' most studies have made use o f inventories such as the 16pf, the minnesota multiphasic personality inventory7 (mmpi), the eysenck personality questionnaire (epi) and the profile o f mood states (poms) to measure personality7 dimensions, but few' have used the theoretical underpinnings o f the ques­ tionnaire to inform their research questions.30 31 h vealey, in her review7, concludes that regardless o f the fact that there is evidence to suggest that runners’ personalities are characterised by introversion, stability, low7 anxiety, self-sufficiency, high self-esteem and imaginativeness, no prototypical athletic personality7 type has yet b een defined.31 6 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:andersons@psy.unp.ac.za with regard to personality and addiction, steinberg and sykes" cite pargman and balter’s review o f the liter­ ature, suggesting that there may b e underlying similari­ ties in the psychological profile o f addicts generally. the idea o f an addictive personality' type has, however, not received much support from current research. nonetheless, researchers continue to investigate the per­ sonality profile o f the addicted exerciser, and more par­ ticularly the runner. 11 27 28 a specific personality' attribute aasociated with addic­ tion, and suggested to b e com mon to addicted exercisers and anorexics, is the obsessive-compulsive and anxious constellation.12 3 compulsive individuals may b e attracted to running as a coping st rategy for stress because o f the repetitive routinized nature o f the activity and its capacity' to facilitate control over mood states as well as physical appearance and functioning.7 although some research supports a higher incidence o f obsessive-compulsive fea­ tures and anxiety' in addicted runners, other evidence sug­ gests that runners present with diverse personality traits without significant pathology.301331 blumenthal, o toole and chang found that addicted runners scored within d ie normal range on the mmpi, and in addition found that even the m ost severely addicted runners did not exhibit significant psychopathology as measured by the mmpi.13 they argued that a disease model o f the addicted runner w'as misleading and unnecessarily pejorative. yates, shisslak, allander and crago found the obligatory and non-obligatory runners in their study to have more simi­ larities than differences, although obligatory runners tended to prefer social isolation.29 others have found male obligator}7 runners to b e more motivated by achievement and a need for recognition.2” thus som e trends have emerged in recent research although no theoretical con­ ceptualisation o f personality or running addiction has informed these studies. a further area o f interest to the present study is the rel­ atively well established finding that exercise results in an increase in positive m ood states and a decrease in nega­ tive m ood states (e.g. anxiety and depression), and that physical exercise is associated with positive nioocl.h lsln:11 chan and grossman17 cite morgan and pollock as noting that, compared to non-exercisers, runners w'ere found to be lower in depression, fatigue, confusion, and tension as measured by' the poms, and hypothesized that these mood differences w'ere a positive consequence o f running. millon2'’ cites morgan as finding similar evidence, and naming this constellation o f scores the ‘iceberg profile’ by virtue o f it’s visual graphic configuration. this finding may also indicate that individuals with more positive mood characteristics choose to exercise, and that addicted run­ ners d o not derive the positive mood benefits from run­ ning. purpose of the study in view' o f the uncertain findings in the literature 011 the relationship between personality and mood states and running addiction, this study aimed to examine whether negatively addicted runners are characterized by a com ­ pulsive personality' style (as measured on the compulsive scale o f the mcmi). furthermore it was proposed to examine w'hether there are any other personality differ­ ences that distinguish negatively addicted runners from non-addicted runners, and whether addicted runners tended to demonstrate greater mood disturbance 011 the poms. further investigation into these variables could shed light 011 management and intervention programmes lor use by clinicians, coaches, and athletes. theodore mulon’s biosocial learning theory' o f person­ ality w'as used to conceptualise personality functioning.2420 personality is defined by millon as: a d istinctive configuration o f interlocking perceptions, feelings, thoughts and beha\iors that provide a tem ­ plate and disposition for maintaining psychic viability and stability (p. 643).2,1 pathology is viewed as occupying the extreme end o f a continuum o f normal behaviour, and differentiated by the following three features: functional inflexibility and rigid­ ity; a tendency' to foster vicious or self defeating circles o f behaviour; and tenuous structural stability under condi­ tions of stress.20 each personality scale is thus construct­ ed on the basis o f a personality prototype rather than a syndrome or type against which individuals are compared for their closeness o f fit.2' each prototype is m ade up o f a small and distinctive group o f primary' attributes that persist over time” (p. 673), that are utilised by the indi­ vidual to ensure predictability, viability, and control in adaptive contexts. these prototypes have been opera­ tionalized in the millon clinical multiaxial inventory (mcmi) and its revisions (mcmt-ii and mcmi-iii). methodology subjects an opportunity sample was secured from a list o f m em ­ bers o f a university athletics club and a list o f those run­ ners from tlie club who had com pleted the comrades marathon in that year. the remaining runners were drawn from two running clubs in kwazulu-natal on the basis of their commitment to a regular running pro­ gramme. the final sample consisted o f 49 runners (33 males and 16 females), ranging in age from 19 to 63 ( = 25.84 years). a comparison group o f 34 non-exercisers (14 males and 20 lemales) was selected by opportunity sampling, from a university staff/student population. they ranged in age from 19 to 50 ( = 2 3 .2 years). they were selected on the basis that they d id not participate in regular exercise (i.e. two or more times a week). exercise was either sporadic and/or primarily o f a low intensity, e.g. casual walking or yogax the runners were assigned to one o f three groups on the basis o f their scores on the hailey and bailey negative addiction scale (see results section).13 x instruments information questionnaire this instrument included biographical information and questions relating to the different types o f exercise the subjects typically engaged in, the intensity' frequency, duration o f such exercise, and motives for exercising. the negative addiction scale the negative addiction scale (nas) was designed by hailey and bailey111 to objectively quantify' the psychologi­ cal aspects o f morgan’s concept o f ‘negative addiction’. it is a 14-item questionnaire that yields a single addiction score ranging from 0 (low) to 14 (high). furst and g em ion e1 found that although the maximum score on this scale is 14, the m ost highly addicted runners in their study had a mean addiction score o f 6.38. no research has sports medicine november 1997 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) been done to identify the point on this scale at which the onset o f addiction to running occurs. ’ t he psychometric properties o f this scale (ie. validity and reliability) are not mentioned, but it was, however, the m ost available scale at the time o f the research. thornton and scottr have sub­ sequently used this scale with some success. profile o f mood states (pom s) t he poms-’ was designed to measure transient and fluc­ tuating m ood states,10 although it is regarded by some researchers,3132 as a dispositional measure rather than a state measure o f personality. the scale is noted by morris32 as having been extensively used in at least 12 studies suc­ cessfully distinguishing levels and types o f athletic per­ formance. it has 65 items that consist o f adjectives describing various feelings and moods, each o f which is rated on a 5-point intensity scale. the results yield six dimensions o f mood: tension/anxiety; depression/dejec­ tion; anger/hostility; vigor/activity; fatigue/inertia; confu­ sion/bewilderment. vigor is subtracted from the total o f the other five m ood states to provide a total mood disturbance score, with a high score indicating poor adjustment. this total m ood disturbance score is highly reliable because o f the inter-correlations among the six primary poms factors, and reliability o f the scales ranges from 0.65 to 0.90.23 miuon clinical multiajdal inventory (mcmi) t he mcmf4 consists o f 175 items, from w h i c h 20 scales are derived. scales 1 8 reflect the persistent, ingrained, enduring and pervasive personality characteristics or ‘per­ sonality style’ o f an individual. scales s, c, and p reflect a greater level o f pathology in the p e r s o n a l i t y pattern, while scales a through pp are clinical syndrome dimensions that reflect current symptom states o f a transient nature (i.e. symptoms that fluctuate over time in response to the impact o f stressful situations). these latter symptoms typ­ ically exacerbate the basic personality style. test-retest reliability indicates that the overall stabili­ ty o f the mcmi scales is reasonable, with an average around 0.80 for both the personality patterns and the pathological personality scales.24 stability for the clinical syndromes, which are more transient and will inevitably fluctuate, is lower at 0.65.24 concurrent validity was sup­ ported by correlational data between the mcmi scales and three comparable diagnostic inventories, including them m pi. b a s e r a t e scores provide uniform cutting lines: the br75 cutting line is drawn to identify the presence o f a trait or disorder. the br85 cutting line represents the most prominent s\ndronie(s). results (a ) negative addiction administration o f the nas to the runners revealed a wide spread o f scores (range 1-13; = 3,82, sd = 2.45). following the findings o f hailey and bailey, the runners were assigned to one o f three groups on the basis o f their level o f negative addiction on the nas (see table 1). the high addiction subgroup comprised 11 runners (6 male, 5 female) scoring 6 or more on the nas (hailey and bailey note that the mean addiction score for the m ost highly addicted runners in their sample was 6.38; sd = 2.61). t he low7 addiction subgroup consisted o f a group o f seven male and three female runners, with negative addiction scores o f 4 and 5. t he non-addicted subgroup (21 male, 6 female) w ere identified on the basis o f their nas scores between 1 and 3. a median split technique o f the negative addiction scale scores (median = 3) supported this group­ ing. table i. sub-groupings o f runners on the negative a ddiction scale (n 4 9) subgroup n mean sd range h igh a ddiction 11 6.36 1.27 6-13 low7 addiction 10 4.10 0.32 4-5 n on-addicted 28 2.21 0.75 1-3 a series o f one-way anovas failed to reveal any group dif­ ferences between the high and moderate addicted run­ ners on any o f the variables, and so these two groups were collapsed into a single group (addicted runners; = 3.80; sd = 2.46) for the remainder o f d ie statistical analysis. ( b ) mood states t h e results for the three groups on the profile o f mood states (poms) are summarized in table ii (groups col­ lapsed for sex) and figure 1. table ii. poms raw7 scores (and sds) for the a dd icted and n on-a ddicted runners, and the non-exercisers. scale addicted non-addicted non-exercisers runners runners tension 9.90 (6.08) 7.78 (4.17) 10.12 (5.48) depression 8.90 (7.61) 5.15 (4.26) 10.57 (9.68)* anger 8.65 (7.47) 5.07 (3.80) 10.57 (9.68)* vigor 21.00 (4.88) 30.96 (3.03) 14.24 (5.90)** fatigue 7.20 (5.84) 4.81 (4.10) 8.91 (5.43)* contusion 7.80 (6.01) 6.07 (3.35) 8.36 (5.17) tmd 21.15 (25.01) 7.93 (14.56) 33.59 (28.36)* significant group difference *p <.05; **p <.001 tmd = total mood disturbance a significant difference between the non-exercisers and non-addicted runners, emerged on the anger (f = 3.53, p < 0.05), depression (f = 3.76, p < 0.05), fatigue (f = 4.73, p < 0.05) and total m ood disturbance (f = 8.8 1, p < .00 1) scores o f the poms (scheffe’ post-hoc, p < .05). the vigor subscale also revealed a significant difference (f = 18.76, p < 0.001), between the runners as a w7hole, and the non-exercisers (scheffe post-hoc). in order to assess the clinical significance of the poms scores, the groups were compared for the presence o f scores (excluding vigor), above the clinical cut-off point o f t > 60. results revealed a significant group differences using chi-squared (f = 9.16, p < 0.02), with the non-addicted runners showing less overall emotional disturbance than the non-exercis­ ers. t he poms vigor scale w7as examined separately (it is the only positive mood state), and show7ed that the non­ exercisers reported less vigour than the addicted and non-addicted runners (f = 13)21, p < 0.001). since the scoring o f the poms is not adjusted for sex, investigation o f potential gender differences was m ade using a two-way anova (group by sex); however, this failed to reveal any 8 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table iii. mcmi base rate (br) means and sds for the addicted and noil-addicted rnniiers, and tlie non-exercisers. personality patterns addicted lion-addicted scale runners runners non-exercisers schizoid (1) avoidant (2) dependent (3) histrionic (4) narcissistic (5) antisocial (6) compulsive (7) passive39.29 (25.53) 40.80 (21.31) 68.52(23.41) 66.71 (20.46) 63.52 (13.71) 56.76 (20.67) 65.71 (17.34) 26.25 (17.05) 23.54 (19.12) 50.14 (28.24) 73.04 (15.69) 70.79 (15.37) 62.00 (20.66) 64.50 ( 9.30) 33.85 (23.28) 28.71 (21.60)* 48.97 (26.56)* 74.26 (24.86) 69.56 (20.83) 58.24 (20.01) 64.06 (11.38) aggressive (8) schizotypal (s) borderline (c) paranoid (p) 36.42 (24:42) 56.48 (10.03) 57.52 (16.17) 60.38 (17.85) 30.75 (14.20) 40.39 (20.30) 46.75 (18.54) 63.43 (13.15) 39.53 (21.21) 44.71 (17.56)** 54.91 (19.22) 56.85 (19.46) clinical syndromes anxiety (a) somatoform (ii) hypomanic (n) dysthymic (d) alcohol abuse (b) drug abuse (t) psychotic thinking (ss) psychotic depression (cc) psychotic delusions (pp) 74,67 (15.28) 73.33 (14.94) 47.95 (30.60) 64.52 (15:33) 46.57 (19.64) 56.00 (18.69) 51.38 (9.98) 41.33 (17.27) 52.76 (18.48) 59.93 (21.67) 68.44 (21.82)* 65.32 (17.57) 68.12 (14.62) 50.79 (21.38) 46.85 (28.50) 49.39 (18.72) 62.15 (21.02)** 47.29 (13.03) 47.03 (21.07) 61.79 (14.31) 56.06 (24.31) 41.46 (21.73) 44.24 (17.86) 34.82 (15.89) 40.47 (18.85) 49.89 (20.21) 47.29 (22.24) profile differences between males and females. ( c ) personality and psychopathology group data for the mcmi basic personality profiles and clinical symptom scales are shown in table iii and figure 2. a series o f one-way anovas revealed significant group differences for two o f the personality scales (avoidant, dependent, and schizotypal), as well as for two o f the clin­ ical syndrome scales (anxiety and dysthymia). post-hoc group comparisons (scheffe, p < .05) showed that the addicted runners differed significantly from the non-addicted runners on the avoidant (f = 4.29, p < .05), schizotypal (f = 5.56, p < 0.05), and anxiety (f = 3.27, p < 0.05) scales, whereas the scores o f the dysthymic scale showed that the non-addicted runners were less depressed than both the addicted runners mid non-exer­ cisers (f = 4.92, p < 0.01). in order to ch eck for the pres­ ence o f clinical pathology on the mcmi, subject profiles addicted ----------non-addicted non-exercisers figure 1. poms scores for addicted and non-addicted runners, and non-exercisers. were examined for the presence o f personality and symp­ tom dimension scores at or above the clinical cut-off base rate o f br75. although there were a number o f individ­ ual cases in which d ie cut-offs were exceeded, diere were no overall group differences suggestive o f pathology for the clinical syndromes (f = 3.75, p < 0.20); pathological personality scales o f schizotypal, borderline and paranoid (f = 1.09, p < 0.20); or the basic personality scales (/■’ = 3.86, p < 0. 1 0) using chi-squared. to further investigate personality differences between groups, one-way (group) and two-way (group by sex) aiyova’s were run using the mcmi scales that were sug­ gested in a four fold factor matrix by millon.24 significant group (f = 4.12, p < 0.05) differences emerged for factor 1 with a post hoc schelfe (p < 0.05) analysis indicating that the addicted runners were more emotionally labile and depressed than the non-addicted runners. factor 1 is described by millon24 as “ depressed and labile emotional­ ity expressed in affective moodiness and neurotic com ­ plaints” (p. 49). the scales with maximal positive load­ ings (> 0.80), on diis factor were borderline, dysthymia, anxiety, psychotic depression, passive aggressive and histrionic. the avoidant, schizotypal, hypomanic and psychotic thinking scales loaded between 0.40 and 0.80. the compulsive scale loaded significandy negatively on factor 1 (-0.747). group by sex (f = 2.644, p = 0.077), and group (f= 2.963, p = 0.057), differences approached sigsignificant group difference *(p<.05) **(p <.01) 80 70. 8 60. 8 5010 mcmi scales ----------addicted -----------non-addicted ............ non-exercisers figure 2. mcmi scores fo r the a d dicted and non a ddicted runners, and non-exercisers, a nificance on factor 3. the addicted male runners tended to be more asocial and avoidant, and low on sociability and self confidence. factor 3 is described by millon-’ as a “ core pattern o f schizoid behavioural detachment and thought sports medicine november 1997 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) with positive loadings on scliizoid, avoidant and psychot­ ic thinking” (p. 50). sex differences approached signifi­ cance (f = 3.681, p = 0.059) on factor 4, with females showing a trend o f greater social restraint than d ie male runners. there were no significant group or group by sex differences on factor 2, (this factor is related to paranoid diinking and behaviour with associated grandiosity and suspiciousness). the addicted runners thus tend to be emotionally labile, and this is associated, particularly in the male runners, with low sociability and low s e lf confi­ dence. in order to identify which mcmi personality scales b est predicted group membership for addicted and non addicted runners, a discriminant function analysis (dfa) was performed. this was preceded by a factor analysis (n = 49) in which four factors were extracted (varimax rota­ tion); these were: factor 1 somatization (0.92), dependent (0.84), borderline (0.76), anxiety (0.75), and antisocial (-0.79); factor 2 drug abuse (0.87), alcohol abuse (0.82), hypomania (0.73), passive-aggressive (0.70), histrionic, and compulsive (-0.71); factor 3 schizoid (0.88), avoidant (0.79), schizotypal (0.72), psychotic thinking (0.66), and histrionic (-0.62); while factor 4 was comprised o f psychotic delusions (0.97) and paranoid (0.68). an insufficient number o f variables left in the correlation matrix excluded d ie identification o f any further factors. three o f these factors (namely factors 1, 3 and 4), suc­ cessfully discriminated the addicted and non-addicted runners (respective wilks’ lambda were: .84 for factor 3 (p < 0.005); 0.80 for factor 1 (p < 0.006); and 0.78 for factor 4 (p < 0.009). canonical discriminant function c o ­ efficients were 0.417, 0.901 and -0.44 for d ie respective factors f 1, f3 and f4. t he results o f the dfa found that these factors were successful in classifying 76.2% o f die addicted runners and 71.4% o f the non-addicted runnel's. t he overall correct classification was 73.47%. a stepwise multiple regression analysis was also per­ formed wil.li scores from d ie nas as d ie dependent vari­ able,. the first predicted variable was duration o f exercise, which accounted for 21% o f die nas variance (f = 11.4, p < 0.01). witii the addition o f d ie schizotypal personality subscale from die mcmi, diis percentage increased to 31% (f = 9.3, p < 0.001). finally, d ie addition o f a tiiird predictor, namely sex, accounted for 40% o f the overall variance o f d ie nas scores (f = 8.8, p < 0.001). finally, in order to identify which variables b est pre­ dicted schizotypal personality, an additional stepwise multiple regression analysis was performed on d ie data. on the first step, the total mood disturbance score (poms) emerged as d ie significant variable, accounting for 16% o f the variance (f = 7.9, p < 0.01). the second variable (duration o f exercise) accounted for a further 9% (total variance 24%; f = 6.5, p < 0.0 1). finally, intensity o f exercise (questionairre data) contributed a further 11 % (total 3 5%; f = 7.2, p < 0.00 1). the 0.05 limits were reached following tiiis last extracted variable. discussion the identification o f addicted versus non-addicted run­ ners using an arbitrarily-detennined cutoff point on the nas wras d ie source o f some concern to d ie researchers. however, a median split o f 3 in the current study suggest­ ed that the cut-off point used by hailey and bailey10 was compatible widi our own findings, and represents a useful clinical guideline. we would support a view' tiiat further psychometric research is desirable to fully explore d ie validity o f nas cut-off points. t he m ost prominent feature o f the poms was d ie ‘ice­ berg profile’ that distinguished the two running groups (high and low addiction) from the non-exercisers (see fig. 1). this finding is consistent with previous research diat has found that exercising individuals are characterised by higher levels o f energy (vigor) and lower levels o f em o­ tionality dian non-exercisers.1823 the other poms findings (i.e. total mood disturbance score, anger, and fatigue) also appear to suggest tiiat running is associated with emotional well-being; however, analysis o f non-significant trends in the data suggest that this benefit is maximal for d ie non-addicted runners. it should b e pointed out that considerable overlap exists in the total m ood disturbance scores for the addicted and non-addicted runners, as well as for the addicted runners and non-exercisers (see table id. the mcmi results lend themselves to useful clinical interpretation. while the results revealed few7 significant overall group differences, the finding tiiat d ie addicted runners w'ere significantly different from both the non addicted runners and non-exercisers on the dysthymic scale provides further support for the idea that non addicted running either promotes positive mood states, or reduces depressed mood. in terms o f personality profiles, our results suggest that running addiction is correlated witii specific personality dispositions, in particular, die schizotypal personality. this refers to a constellation o f personality dispositions characterized primarily by social detaclunent, a preference for privacy and isolation, and d ie display o f unobtrusive aloofness associated with a ten­ dency towards behavioural eccentricities and low7 self esteem. in addition, there was evidence o f a wrealter correlation between running addiction and avoidant and dependent personality patterns. the avoidant pattern has similari­ ties with d ie schizotypal disposition in that it is also char­ acterised by social detachment, but witii greater emotion­ al lability, tension, and anger. o f interest to d ie overall aim o f diis study wras the finding tiiat ruiming addiction is not represented by a personality profile that features prominent compulsive dispositions. this dissociation between what on the surface might appear to be com pul­ sive behaviour (i.e. running addiction), and compulsive personality traits, can be interpreted witii reference to millon’s theory' o f personality as operationalized in the mcmi. to this extent, addicted running appears to be more closely associated with general, rigid, inflexible per­ sonality patterns o f a schizotypal and avoidant nature, in which emotionality has higher prominence than d ie com ­ pulsive personality disposition which millon describes as being characterised by restrained emotionality. t he sig­ nificant negative correlations (from -.17 to -.38), between the compulsive sub-scale on the mcmi and all o f the poms subscales, supports this observation. a further point worth noting concerns d ie largely nega­ tive correlations (from a non-significant -0.03 to a signifi­ cant -0.27), between m ost o f the mcmi clinical scales and the vigor subscale o f the poms. this relationship con­ firms the com m on sense expectation that increased feel­ ings o f energy and w'ell-being would be incompatible widi psychological symptomatology in runners. this is partic­ ularly so in relation to the dysthymia sub-scale, w'here the relationship is significantly negative (r = -0.27, p < 0.01). other comparisons between the two clinical instruments used in this study are suggestive o f an association between 10 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) negative m ood state (as measured by the poms), and a tendency towards specific types o f personality disposi­ tions. for example, our results suggest negative correla­ tions between the total m ood disturbance score and the compulsive personality subtype (-0.31), and high positive correlations (p < 0.001) with avoidant (0.41), passive aggressive (0.55), schizotypal (0.34), and borderline (0.49). somewhat weaker correlations characterized the relationship betw een total m ood disturbance and schizoid (0.28) and narcissistic (-0.28) personality sub types. in relation to prerious research documenting the rela lionsliip between running addiction and personality,1328,29 there is some concordance with the yates et al. study that found obligatory runners to prefer social isolation.29 however, blumentlial et al. found no significant differ­ ences between addicted and non-addicted runners using d ie mmpi, and they caution against pathologizing running addiction.™ the findings o f the present study cannot b e directly compared to die blmnenthal study as the theo­ retical lmderpinnings o f the mmpi and d ie mcmi are somewhat different. the rational for the mcmi is a theo­ ry o f personality, whereas the mmpi is based on a theory o f psychopathology. furthermore, millon describes per­ sonality traits as dispositions, and views his sub-types as prototypes against which persons are compared for their closeness o f fit; this has important implicat ions for inter­ pretation o f findings such as ours.20 27 millon stresses t hat the personality dispositions o f the person approximate the prototype to a greater or lesser degree, rather than being classified into discrete, pathological categories. to this extent, we would concur with blumentlial and colleagues, that a rigid categorisation o f atliletes into personality and psycliopadiological subtypes is misleading and undeserv­ ing. specifically, researchers need to contextualize their results and interpretations with reference to the theoreti­ cal underpinnings o f the instruments used. such an approach, would hopefully lead to increased understand­ ing o f the dynamic psychological processes underlying run­ ning addiction. in terms o f our suggestions for further research, d ie extent to wliich our findings are generalizable to other sports w ould be an important extension. further studies on d ie utility and reliability o f the nas also seem wrar ranted, given that parameters o f running addiction (e.g. stage-like process) have not yet been sufficiently opera­ tionalised, despite pioneering attempts in this regard.2 9,15'-22 li view* o f die criticisms directed at personality trait r e s e a r c h , d i e use o f more interactional and idio grapliic research designs, in an attempt to examine the relationsliip between personality and running more specif­ ically, needs to b e implemented. furthermore multi-dis­ ciplinary and multivariate statistical procedures that include biophysical, psychological and sport skill vari­ ables;^ may b e useful in furthering the knowledge base in this important area o f sport psychology. references /. coen sp &. ogles bm (1 9 9 3 ). psychological characteristics o f the oblig­ atory runner: a critical examination o f the a norexia analogue hypothesis. journal o f sport and exercise psychology, 15,338-854. 2. sachs ml (1 9 8 1 ). running addiction. in m sacks & m sachs (e d s.), psychology o f running, pp. 116-125. champaign hi: human kinetics. 3. veals d (1 9 9 5 ). does primary exercise dependence really exist? in j annett, b cripps, and h steinberg (e d s.), exercise addiction: motivation for participation in sport and exercise. london: bps. 4. sachs m l & p a rg m a n d (1 9 7 9 ). running addiction: a depth interview examination. journal o f sport behaviour, 2, 143-155. 5. colt ewd, dunner dl.,.ilau k & fieve r r (1 9 8 1 ). in m sacks & m sachs (ecls.), psychology o f running, pp. 234-245 champaign iu: human kinetics. 6. de coverley veale d m w (1 9 8 7 ). exercise dependence. british journal o f addiction. 82. 735-740. 7. sacks m h (1 9 8 1 ). running addiction. a clinical report. in m sacks & m sachs (e d s.), psychology o f running pp. 127-129.champaign hi: human kinetics. 8. biddle s i l l &. mutrie n. (1 9 9 1 ). psycholo<jy o f physiccd a ctivity and exercise. london: springer-verlag. 9. furst dm &. germone k (1 9 9 3 ). negative addiction in male and female runners and exercisers. perceptual and m otor skilis. 77, 192-194. 10. kremer jm d & scully d m (1 9 9 5 ). psychology in sport. i^ondon: taylor francis. 11. steinl?erg 11 & sykes ea (1 9 8 5 ). introduction to symposium on endor­ phins and behavioural processes: review o f literature on endorphins and exercise. pharmacology. biochetnisiry and behaviour, 3, 857-862. 12. sours j a (1 9 8 1 ). running, anorexia nervosa and perfection. in m sacks & m sachs (e d s.), psychology o f running pp. 80-89. champaign iii: human kinetics. 13. blumentlial ja, o ’toole lc & chang jl (1 9 8 4 ). is running an ana­ logue o f anorexia nervosa? journal o f the a m erican medical association, 252, pp 520-523. 14. marcus b ii, b<x:k bc. pinto bm & clark mm. (1 9 9 6 ). exercise initi­ ation. adoption and maintenance. in van raalte & b\v brewer ( e d s). exploring sport and exercise psychouygij, washington: apa . pp 133-158. 15. sime w (1 9 9 6 ). guidelines for the clinical applications o f exercise ther apy for mental health. in jl van raalte & b w brewer (e ds). exploriiuj sport and exercise psychology. washington: a pa . pp 159 186. 16. c ox r (1 9 9 4 ). sport p sych ology: c oncepts and applications. maddison brown & benchmark. 17. chan cs & grossman iiy (1 9 8 8 ). psycfuaogical effects o f running loss on consistent runners. perceptual and m otor skills, 66, 875-883. 18. gondola jc & tuckman b w (1 9 8 2 ). psychological mood sta te in ‘average’ marathon runners. perceptual and motor skills, 55, 1295 1300. 19. hailey hj & bailey la (1 9 8 2 ). negative addiction in runners: a quan­ titative approach. journal o f sport behaviour. 5, 150-154. 20. biddle stii & fox k r (1 9 8 9 ). exercise and health psychology: emenfing relationships. british journal o f medical psychology, 62, 205-216. 3 / . rudy kb & estofc pj (19.90). running addiction and dyadic adjust­ ment. research in nurving and health. 13, 219-225. 22. 'thornton e w &. scott se (1 9 9 5 ). motivation in the committed runner: correlations between self-report scales and behaviour. health promotion international, 10, 177-184. 23. mcnair dm, lorr m & dropplenuin lf (1 9 9 2 ). edits manual for the profile ofm otxl states. s<ui diego. califomuv edits/ educationfd and industrial testing service. 24. millon t (e d .) (1 9 7 3 ). 'theories <if psychopathology and personality. 2nd ed. philadelphia' wb saunders. 25. millon t (1 9 7 7 ). millon clinical multiaxud inventory manual (3rd e d). u.s.a.: interjjretive scoring systems. 26. millon t ( 1986a). a theoretical derivation o f pathologic<dpersonalities. in t millon. & gl klerman contem porary d irections in psychojxithology. new york: 'ihe guilford press. 27. millon t (1 9 8 6 b ). personality prototypes and their diagnostic criteria. in t millon. & gl klerman. contem porary d irections in psychopathology. new york: the guilford press. 28. ogles bm. masters ks &: richardson sa (1 9 9 5 ). obligatory running and gender: a n analysis o f participative motives and training hai>its. international journal o f sport psychology. 26, 233-248. 29. hites a . shisslack cm, a llenderj & crago m (1 9 9 2 ). comparing oblig­ atory to nonobligatory runners. psychosomatics. 33, 180-189. 30. fields kb, delaney m &. hinkle js. (1 9 9 0 ). a prospective study o f type a ijehiavior and running injuries. journal o f family practice, 30, 425-429. 31. van der auweele y, de cuyfjer b, van mele v & rzewricke r (1 9 9 3 ). elite performance and f?ersonality: from description and prediction to diagnosis and intervention. in rn singer, m murphy & l k tennant, (e d s.). handbook o f research on sjx>rt psycholo<jy. new york: mcmillan. 32. ve(dey rs (1 9 9 2 ). personality and sport: a comprehensive review. in ts horn (e d .), a dvances in sjx>rt psychology. champaigns. hi: human kinetics. 33. morris t (1 9 9 5 ). p sychohgiad characteristics and sports behaviour. in t morris & j summers, sports psychology. theory, application and issues. brisbane: john wiley & sons. 34. regnier g. s<dmela j, &. russell s i (1 9 9 3 ). talent detection and devel­ opment in sport. in rn singer, m murphy & lk tennant, (e ds.). handbook o f research on sport psychology. new tor/c: mcmillan. q sports medicine november 1997 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychological preparation for a low intensity marothon squash event c j b asson, ma, bed, ued, departm ent o f psychology, university o f natal, pietermaritzburg. abstract this ca se study describes the psychological preparation and intervention in a low intensity marathon event. a successful attem pt was made on a world squash p la y­ ing marathon record, and although the players were assisted by other professionals, it was decided to report the contribution o f the psychological intervention. a holistic approach based on the individual needs o f the players was designed, and the particular use and appli­ cation o f relaxation, imagery and re-interpretation o f stimuli and responses is described. the application o f various p sy ch o lo g ica l interven tion tech niques is described in relation to their use to manage monotony, sensory habituation and sensory distortions, sleep and rest deprivation and team building. the aim o f the case study is to provide practitioners with som e guidelines fo r intervention in similar sporting events. introduction increasingly, sports scientists have recognised the im portant role that psychology can play in th e p rep a ­ ra tion for low in tensity m a ra th on events. investigations into th e motivation o f m arathon run­ n e r s 1, ch a n g es o f m ood states during and after m arathon events,2'34 and th e effects o f marathon events on sleep cy cles,5 have recently b e e n reported in th e literature. t h is paper d escrib es selected p sy ch o ­ logical approaches u sed to prepare and support two elite squash players in th eir attem pt to establish a w orld record attem pt o f 134 hours, in a squash marathon in august 1995. in addition to describing the psych ological preparation, the article stresses the im portance o f a m ulti-professional approach to p rep a ­ ration and support. c onceptualising the intervention a pp roa ch it is im perative th at in a m arathon event such as this, th e p sychological input n eed s to b e app roa ch ed in a m ulti-professional team context.07 in addition to the clinical psychologist, the following professionals were involved with assisting in th e preparation for, as well as assistance (luring th e event: a b iok in eticist and exercise specialist; a sports physician, a team o f p h y s­ iotherapists; and a dietician. a lthough th e main focus o f th is article is on the psychological intervention, this in no way detracts from the significance o f th e con tri­ b utions o f the oth er d isciplines. it was agreed b y the participating p rofessionals that this particular aspect o f th e program m e sh ould b e reported in greater detail. g uiding princip les for th e intervention w ere based on th e following behaviours that have b e e n foim d to contribute to enhanced perform ance8: “ intentionality, clear focus, total absorption in the task, effortless con ­ centration, feelings o f the b o d y p erform ing on it’s own w ith out fatigue, loss o f fear, and certainty o f s u cce s s .” hardy8 also m entions the su ccess o f program m es that train sport persons in th e use o f m eta-cognitive skills, to assist th e athlete in greater s e lf regulation o f a ffec­ tive, motivational and fatigue states in com petition. a d d ition a l th eoretica l su pp ort for guiding th e ch o ice o f intervention strategies was taken from richard lazarus’s10 adaptational m odel o f em otions, and steven a pter’s reversal theory. 1112 t h e value o f a cognitive-relational-m otivational approach to inter­ vention10, lies in th e fact that it em p hasises th e active role o f adaptive p rob lem solving in explaining e m o ­ tional responses to particular environmental contexts. a pter’s reversal t heory,1112 was used to understand and plan for maintaining m otivation in the event. t he concepts, telic and paratelic m etam otivational states, are used by a pter to refer to p olarised states o f m o ti­ vational arousal betw een w h ich an individual can shift. when in a telic state th e individual is goal d irected , serious m in ded and pi an fill, and attem pts to avoid arousal. w hereas in th e paratelic state high arousal and im m ediate pleasure relating to th e activi­ ty are evident, as are spontaneity and playfulness. a ccord ing to kerr,12 an attitude o f playfulness would engender natural curiosity, spontaneity and creativity in approaching such an arduous event, and thus enhance th e enjoym ent o f the activity in itself. on the other hand telic states would assist in the m ore seri­ ous m inded planning and goal d irected p rob lem solv­ ing n ecessary at tim es w hen future perspectives were necessary. in ord er to endure live days o f continuous play with sustained m otivation and interest in d ie activity, th e players n eed ed to b e assisted to vary their m otivational state betw een telic and paratelic states on a regular basis. t h e way in w h ich arousal could b e m anipulated to enhance m otivation and perform ance, was b a sed on k err’s 11 technique o f meta-m otivational reversal. by this h e m eans that unpleasandy low or high arousal can b e re-interpreted to th e sports p e r ­ son, in ord er to change the direction o f the arousal. t his is sim ilar to the techn iqu e o f reframing u sed in fam ily therapy.14 furthermore th e related techniques o f associative and dissociative m ental strategies inves­ tigated by s chom er,15 w ere also utilised. in summary, the aim o f the intervention was to p ro­ vide th e players with individualised psychological preparation and support in conjunction w idi a m ulti­ p rofessional team as w ell as a student support team. t h e prim ary focus b ein g on the training o f m eta-cog­ nitive skills, and relaxation techn iqu es with associat­ ed m ental im agery p rocedures. m ost important, was to develop an overall attitude o f playfulness towards th e planning of, preparation for and participation in the event. the players t h e participants in th e m arathon event w ere two male students studying on th e pieterm aritzburg cam pus o f the university o f natal, aged 2 4 (player 1), and 20 years (player 2). player 1 is currently a p hd student and player 2 an undergraduate student. b oth players 12 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) con sid er them selves to be ranked in th e top 1-3 % o f the squash players in the natal m idlands region, and player 1 has represented natal, and could b e regard ­ ed as being in the top 5-8 % players in th e province. both players w ere highly m otivated and goal ori­ ented, with low overt anxiety levels throughout the preparation and perform ance phases. t hey had both previously participated in m arathon events, player 1 as a runner, and player 2 as a ca n oeist and in th e m il­ itary. sum m ary o f c onsultations with the players a sum m ary o f th e psychological intervention with the players p rior to and during the event follows: in preparation: 1. five interviews o f approxim ately 1 '/a hours were con d u cted with the players, starting 12 w eeks p rior to th e event. 2. two w eeks p rior to the event, a trial gam e o f 6 hours o f play was arranged on th e advice o f th e bio kineticist. the p sych ologist attended for an hour session, and in th is tim e h e assisted the players to play “ m in d lessly” using relaxation techniques and gu id ed imagery. 3. a group m eeting o f 1 hour was arranged with the student support team. 4. a follow -up session was con d u cted with b oth play­ ers. during the event: twenty consultations o f 10-20 m inutes w ere held with the players on court while they w ere playing or rest­ ing, or during physiotherapy and or m ed ical sessions. t h ese consultations were usually con d u cted 4 tim es per day at 0 8:00, 12:00, 17:00, and 20:00. during this tim e the author rated the players on six, 5 p oin t likert type scales for affective valence, level o f anxiety, goal directed n ess, reported fatigue, level o f reported relaxation, and width o f attention. the selection o f specific skills in the initial consultation w ith b oth players th e p r o ­ p osed event was analysed with regard to the types o f dem ands that it would m ake on them . t h e following areas em erged as focuses for psychological interven­ tion: 1. the p ossibility o f com p rom ised m otivation result­ ing from sensory habituation, m onotony and b o r e ­ d om as a consequence o f th e red uction in novel sensory input during th e m arathon event. 2. a ttending to fatigue and pain emanating from th e repetitive use o f the sam e m uscles, tendons and jo in ts over an extended p eriod o f tim e. 3. m anagem ent o f sleep and rest deprivation d ue to th e requirem ents o f the record attempt. two hours o f rest a day, and 90 secon d s rest betw een each gam e were prescribed. 4. t h e n ecessity o f developing co-operative interac­ tion and mutual support between the two players over an exten d ed tim e period. 5. t h e developm ent o f effective com m unication with and betw een the m em bers o f th e m ulti-profession­ al and student support team s. 6. a ccom m odating th e role o f spectator behaviour in th e perform ance. after this initial consultation with the players, and consideration o f relevant literature,'*'8131510 th e follow ­ ing skills w ere id en tified as bein g im portant in addressing th e p rob lem s iden tified above: g oal-setting and planning mental im agery a rousal control attention control attitude and problem reframing creative prob lem solving inform ation that h ad b een obtained from the players’ consultations with th e m ed ical and param edical team, was integrated into each psychological consultation session w henever it was appropriate. for instance, the inform ation on d iet was u sed in planning rein ­ forcem ent sch ed ules, while the inform ation on p ossi­ b le m edical p rob lem s and muscular p rob lem s was d is ­ cu s s e d releva n t to rela xation and imagery. furtherm ore, inform ation from discussions that the players had had with the student support team, was u sed to plan creative solutions to potential sensory habituation and b ored om problem s. table 1, p rovides a b r ie f summary o f th e content o f th e preparation sessions with th e players and their student support team. table 1. __________ summary o f preparation consultations session no focus 1 initial interview: origin o f the idea; motives; intrinsic and extrinsic motivation; response to failure and success; goaldirectdness; skill level; interpersonal perceptions and supportiveness. 2 start with the training in relaxation tech­ niques using jacobson’s technique o f pro­ gressive relaxation.include guided imagery. practice emphasised 1-2 x daily preferably before sleep. 3 continue with relaxation training. introduce autogenic training very successfully for both. assistance in goal setting short, medium and long term. also assist in looking for rewards. 4continue witii relaxation training and auto­ genic training. talk briefly about their pre­ paredness and the arrangements with the support team. introduce creative problem solving for control o f monotony, and encour­ age attitude o f playfulness. 5 full session on relaxation training. goal set­ ting reassessed. 6 6 hour trial game. support on court by trans­ ferring relaxation techniques and guided imagery to in vivo experience. 7 meet with student support group. spell out the possible effects o f the marathon, as well as the importance o f the novel stimuli with­ out coaxing and demanding performance. 8 follow-up meeting with the two players to evaluate the experience and the impact o f ______________ the event. sports medicine november 1997 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m entel preparation and intervention with the players t h e abovem entioned five target areas w ere selected as foci in the intervention program m e. each area will be d iscu ssed in relation to th e preparation phase, and to th e sessions oil court respectively. 1. m o n o to n y /b o re d o m /s e n s o ry habituation 1.1 in a low intensity marathon event in excess o f 130 hours, th ere is a h igh probability that m onotony and sensory habituation w ould result from repetitive play in th e insular environm ent o f a squash court. apart from physical fatigue, th is asp ect was regarded as one o f the focal areas to attend to in th e mental prepara­ tion o f th e players, as well as for orientation o f th e stu­ dent support team . in ord er to a dd ress th is problem , planning was d one around introducing novel and var­ ied sensory stim uli on and o f f court. in addition, the players w ere trained to utilise their paratelic states to develop an attitude o f playfulness and creative p rob ­ lem m anagem ent tow ards the attem pt.12 t his was done b y exploring ways in w h ich they cou ld focus on a spects o f th e event that wotdd have intrinsic enjoy­ m ent for them. in addition, they w ere counselled to sh ift attention to pleasurable activities i f and w h e n they found them selves p reoccu p ied with goal ach ieve­ m ent activities only. in prepa ra tion: variations o f auditory, visual and ta c­ tile stim uli w ere planned to ensu re that the p o ss ib ili­ ty o f sensory habituation would b e red u ced . to m ain­ tain an elem ent o f surprise and novelty, som e o f these variations w ere known to th e players and others were not. s om e exam ples were: painting th e court green, to introduce novelty and to red u ce eye strain; using vary­ ing typ es o f m u s ic and te lev ision p rog ra m m es throughout th e event, arranging to play against social and sporting celeb rities; playing against squash d evel­ opm ent team s and sch oolb oy teams; playing on an adjoining court; taking h ot and co ld show ers; focusing on th e tactile experience o f physiotherapy; changing cloth es and footwear; walking on varying surface tex­ tures, etc. in planning th is aspect, the players were encouraged to participate actively in finding creative and novel experiences that would in som e way engage their hum our and attention. t h is was in line w ith the playfulness referred to b y kerr.12 t h e student support team played a significant role in preparing for this aspect o f the event,, particularly with regard to p lan­ ning novel events and food rewards. on c ourt: relaxation techniques and gu id ed im agery w ere used to p rovid e th e players with skills to “ esca p e” from the court using p ositive imagery. meta m otivational reversals w ere introduced to reinterpret out o f the ordinary arousal states associated w ith p e r­ ceptual distortions or em otional irritations occurring due to fatigue or sensory habituation. an exam ple o f this was when one o f th e players experienced visual distortions o f th e lines on th e front and s id e walls o f th e court. t h e players and the support team had been advised that sensory p henom enon such as th is could occur. h e was assisted to exaggerate th e distortions thereby heightening attentiveness to the stim uli and in so doing red u ce the distortions. on the 4th day, th e sam e player com plained o f the irritating and m on oto­ nous sound o f the b all hitting th e wall. using a sim i­ lar principle as above, h e was encouraged to try to observe the b all closely to d iscover any patterns that it m ade on th e wall when hit. h is creativity lead him to discover, to h is surprise, that th e ball had a s h a d ­ ow and that h e cou ld p red ict th e vector and trajectory o f th e b a ll d epending on th e sh ots h e was playing. a novel visual stim ulus had assisted him to defocus from th e habituated auditory stim ulus. players were also taught to vary th e p ace o f the gam e w hile in a relaxed state, w hich entailed su dd en shifts from slow m in dless play to rapid, h ard hitting play. 1.2 goal setting and rewards. during th e preparation phase, the players w ere assist­ ed in setting short, m edium and lon g term goals, that w ere consistent with their p erceived n eed s and p e r­ sonal preferences. t h ey ch ose food, physiotherapy, and m onitoring o f their heart rate and b ody m ass at th ree-h ou rly intervals as s p e c ific rew ards. t h e record s o f m ass and pulse rate w ere displayed in graphic form at th e entrance to th e court, along with th e full dietary sh eet for the five days. t h is not only acted as a reward and m otivation for th e players, but also as a focus o f interest for the support team and spectators. 1.3 use o f crow d support. t h e court that was u sed was n ot glass-backed, thus lim iting th e novelty o f crow d m ovem ent as a stim ulus, to an upstairs gallery only. it was imperative to ensure that crow d support in th e gallery was consistent and varied, and that it was u sed creatively b y the players to red u ce bored om . t his was an extrem ely important aspect contributing to the continued motivation for the players throughout the entire five days o f the event. t h e support team arranged a w ide variety o f social events at th e venue to ensure a continuous flow o f crow d support, especially in th e early and late evenings. i 2. physical and mental fatigue and pain t here was a d istinct probability that pain, fatigue and overuse injuries could interfere with motivation and perform ance over a five day game. in add ition to the com petent m ed ical and physiotherapy planning and support, psychological techn iqu es to manage th ese eventualities w ere introduced. t h e cognitive-behavioural literatures,1" and the lit­ erature on psychological aspects o f sport injury,10 point to the use of, am ongst others, relaxation techniques, imagery' m anipulation and acknow ledging the painful experience and relabelling it. in preparation: t h e players w ere trained in the use o f progressive relaxation techniques using a m od ified jacobson approach, w h ich was later com bin ed with s ch u ltz’s autogenic training.16 d eep breathing was used as a major facilitator o f th e relaxation training, as this technique is a ccessed with m inim al effort w hile playing. s m ith 17 also maintains that it is easier for sport person s to learn relaxation skills than cogn i­ tive control skills. t h e d ecision to u se both tech ­ niques was inform ed by th e different response that th e two players h ad to relaxation and breathing te c h ­ niques. player 1 found th e active m od e o f progressive relaxation m ore suitable, w hereas, player 2 preferred the passive m od e o f autogenic training and breathing. 14 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) in addition to th e relaxation techniques, im agery rehearsal and gu id ed im agery w ere used to cop e with b ored om and any stress that a ccrued due to fatigue or injury on court: to further enhance the effectiveness o f relaxation and gu ided imagery, the players were gu id ­ ed in in vivo practice o f th ese skills during the trial play o f 6 hours. t h is was done to encourage states o f deep relaxation, and to defocus from the conscious m otor action o f play. t h is encouraged autom atic “ m in d ­ le ss ” play as a m eans o f maintaining motivation when pain and b ored om w ere encountered. relaxation and im agery were thus u sed w hile the players were in a telic state in w hich low arousal is view ed as m otivat­ ing.1' b rief sessions o f this form o f intervention were done on ce a day during the attempt under the supervi­ sion o f th e p sychologist. t h e players were also encour­ aged to use this activity at tim es when they felt it was necessary to alter their motivational states. t h e play­ ers reported using their own creative variations o f this technique, often m im icking th e tone o f voice o f the p sy ­ ch ologist as an aid in the process. 3. s le e p /r e s t deprivation in terms o f th e rules o f th e attempt, th e players w ere allow ed 2 hours o f sleep per day and 9 0 secon d s o f rest b etw een each gam e. c am p b ell20, p oin ts out that restricted sleep has m inimal effects on physical p e r ­ form ance, although craig and c ooper21, suggest that this effect is m od era ted b y high motivational levels. in preparation: relaxation techniques w ere used to ensure that th e players fell asleep rapidly, and enjoyed a d eep sleep in th e two hours available. t h e players were encouraged to practice relaxation tw ice daily in the th ree m onths p rior to increase th e efficiency o f their response to relaxation instructions. sleeping arrangements w ere w ell planned to ensure consistency in the tim ing and th e place o f rest. on court: relaxation techniques w ere used to ensure that th e players cou ld “ re s t” w h ile playing, as w ell as to encourage autom atic ( “ m in d less” ) playing. they were also encouraged to use th e relaxation techniques during th e sh ort rest p eriod s between gam es, w hen eating and w hen receiving physiotherapy. 4. interpersonal co-op era tion /t eam building in p rep a tion : during th e consultations in the prepara­ tion phase, th e players were assisted to clarify their own personal goals and m otives for th e attempt. t h ey also d iscu ssed and clarified their expectations o f one another, as well as their characteristic responses to failure, success, pain and b ored om . t hey w ere encour­ aged to personally resp ond to this inform ation in ord er that no “ h id d e n agendas” sh ou ld interfere with p e r ­ form ance and coping. furtherm ore, this cou ld lead to greater understanding, and pred ictability o f their part­ ner’s, and th eir own m otives and behaviour during the course o f play. on c ourt: during th e consultations on court, the p sy­ ch ologist was alert to any interpersonal tensions that may b e present. i f so, they were a dd ressed and dealt with using appropriate supportive and interpretative psychotherapeutic techniques. t h is was particularly necessary with player 2, w h o on th e fourth day o f the event b eca m e irritable, was withdrawing and found the crow d support too dem anding for him . short s e s ­ sions o f crisis style counselling to locate th e focus o f the problem as w ell as a cognitive refram ing o f h is relationship with th e crow d, and accessing h is well d eveloped ways o f cop ing w ere sufficient to shift the player to a m ore positive state. h e perceived .the crow d as expecting h im to p e r­ form for them , as he saw th em having com e esp ecia l­ ly to see him play. in refraining the problem , h e was offered an interpretation that th e crow d cotdd b e v ic­ ariously experiencing h is pain and suffering to assess w h eth er they them selves w otdd b e able to deal with it. t h e analogy o f spectator behaviour at an a ccident scene was used to h ig h ligh t the com parison. a r e d e ­ fined im age o f him b ein g th e suffering hero for the sake o f th e crow d was sufficient to engage the player in adopting a m ore p ositive attitude to th e crow d, as w ell as placing less pressure on h im se lf to perform . 5. support fo r the m ulti-professional and student support team one o f th e m ost significant aspects o f preparation and perform ance was to ensure that the team o f student helpers were well inform ed o f the p ossible psychologi­ cal effects o f the m arathon attempt. t h e team was briefed as to how to plan novel and interesting stimuli to ensure the m aintenance o f motivation. t hey were advised on the m eth od s to use in motivating the play­ ers that would b e beneficial to them. during the event the p sych ologist consulted with the m em bers o f the student support team to assess w hether any support was necessary for them . w hile the players were receiv­ ing physiotherapy or m ed ical attention, the p sych olo­ gist was available for consultation with the p rofession­ als to assist them in dealing with any psychological consequences o f fatigue and injury. t his was particu­ larly necessary on the day that player 1 n eeded exten­ sive m edical treatm ent due to diarrhea and dehydra­ tion. d iscussion t h e two players w ere successful in playing b eyond the 133 hour lim it to a new tim e o f 1 34 hours. in the absence o f any preand post-event evaluations, the d iscu ssion w ill focus on observations b y th e author, as well as on th e follow -up interview w ith th e players, w ith regard to the p ossib le effects o f th e intervention on th e success o f th e m arathon attempt. from observation o f th e players as w ell as from their own reports it was evident that the extent and intensity o f crow d and student team support was instrum ental in providing a context th at was both sup­ portive, distracting and stim ulating. t h is factor appeared to have h ad an influence on levels o f arousal and m otivation, as well as on sustained goal d ir e cte d ness. t h e players reported that th e gam es o f squash played with celeb rities and in particular, a group o f schoolboys, had a very positive influence on m otiva­ tion and levels o f fatigue. t his may b e interpreted in th e ligh t o f k err’s 11 view on th e reinterpretation o f arousal states to enhance motivation and novelty. b oth players reported that the relaxation and gu id ­ e d im agery techn iqu es had had a positive influence on their perform ance. in addition, the on-court sessions with the p sych ologist w ere found to b e supportive, and enhancing and maintaining motivation and focus. t he learnt ability o f the players to engage in “ m in d less” playing, and to literally distract them selves b y “ going sports medicine november 1997 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) o f f the court in our m in d s” , was o f b enefit in com ba t­ ting fatigue and b ored om . both players reported that their explicit k now ledge o f each oth er’s goals and m otives, as well as th e form o f anticipated support from their partner, assisted in m aintaining goal d irected n ess and motivation. t h is was particularly evident on day 2 w hen player 1 d evelop ed chron ic diarrhoea and had to b e given m edical attention, and th e support o f player 2 was vital in maintaining a c o m ­ m itm ent to th e com pletion o f th e event. in th e latter stages o f th e event it b eca m e evident that player 2 was relying on player 1 to maintain h is ord erly playfulness and passion, and fla y e r 1 d ep en d ed on th e inner c e n ­ tredness o f player 2. in resp ect o f th e effects o f sleep reduction on the perform ance o f th e players, they rep orted that this was n ot a major debilitating factor. t h e literature on th e effects on perform ance,52021 suggest that high motivational states m ilitate against the effects o f sleep reduction and deprivation. in th e light o f the generally high levels o f goal d irected n ess o f the p lay­ ers th is may w ell have played som e role in m aintain­ ing perform ance. t h ere was, however, evidence o f som e m otor effects in that player 1 reported early m orning b ody trem ors that disappeared after about 20 to 30 m inutes o f waking. t h e on set o f sleep was g en ­ erally reported to b e rapid, except for th e first night w here levels o f cognitive arousal from th e m assive crowd support interfered with initial sleep, bu t did not recur on subsequent nights. p ost event sleep pat­ terns rapidly returned to normal within two days o f th e event. b oth players reported perceptual distur­ b a n ces on th e 3 (1 civs following the com pletion o f the event, in th e form o f exaggerated sense o f acceleration w h en driving a m otor vehicle, in th e p resen ce o f actu­ al slowing o f th e vehicle, i.e. th e}' b oth experienced travelling very fast w hen in actual fact they w ere d ri­ ving very slowly. in addition b o th reported h eig h t­ en ed internal proprioceptive sensation. this may b e evidence o f a response to sensory sound habituation, th a t d oes have an effect on kinesis. b oth players had ex p e rie n ce d th e e ffe c ts o f marathon events in canoeing and running, and had sets o f m em ories to retrieve for personal evaluation and p red iction o f th e effects o f the event. t heir co n ­ sistently high m otivational levels and goal d ir e cte d ­ ness were also p ossib le contributors to the su ccess o f th e intervention and th e m arath on event. t h eir observed response to fatigue and pain was invariably characterised b y continued goal d irected n ess and p o s ­ itive affect. c onclusion from this ca se stud}' it appears that th e areas o f im portance in preparing marathon athletes are th e m anagem ent o f sensory' habituation, fatigue and pain, th e relationship betw een team m em bers and the im portance o f crow d support. in particular, p sy ch olo­ gists need to attend to varying sensory stim uli as a m eans o f reducing th e dem otivating effects o f sensory habituation in marathon events. furtherm ore it wotdd appear that teaching athletes to vary their motivational state betw een goal d irected n ess and playfulness, m ay have th e effect o f sustaining interest over an extend ed p eriod o f tim e. t h e use o f relaxation teclin iques and im agery w ere found to b e b eneficial to sustained m otivation and perform ance, and was useful in varying and shifting attention when necessary. w hat was im portant was the continued supportiveness o f a clinician to facilitate th e ongoing use o f learnt c o p ­ ing strategies, and to assist players in managing p sy ­ chological states associated w ith sensory habituation. apart from th e success o f th e event, p sychologists can use th ese events to investigate th e dem ands that such an event will make on human p sychological adapta­ tion. it wotdd have b een o f value to have con d u cted m ore rigorous assessm ents o f perceptual, m otor and n eu rop sy ch ologica l and em otional-cognitivem otiva tional functioning during th e course o f th e event as was d one b y other researchers in th e fie ld .1 2 3 45 references 1. m asters ks & o gles bm. a n investigation o f the different m otiva­ tions o f m arathon runners. journal o f sport behavior. 1 8 ( 1 ) . 1990. 69-79. 2. schomer h h & d une tt. e m otional transitions o f novice runners during a 7 m onth m arathon training program m e. international journal o f sport p sychology. 2 5 ( 2 ) . 1994. 176-186. 3. tharion. wj., strowman. sr.. &. r auch,. tm. profile and changes in m oods o f ultram araihoners. journal o f sport and e xercise p sych ology. 1 0 ( 2 ) . 1988, 229-235. 4. d oucham ps-r iboux f. h ein z j k & d oucham ps j. a ro u sa l as a tridim ensional variable: a n explora tory stu dy o f behavioural changes in rowers follow ing a marathon race. international journal o f sport psychology. 2 0 ( 1 ) . 1989, 31-41. 5. edinger, jd.. marsh, gr. mccall. & erwin, c w d a ytim e functioning and nightim e sleep before, during, and after a 146 hour tennis m atch. sleep. 1 3 (-1 6 ), 1990. 526-532. 6. b akker, f.c.. w h itin g ti.t.a., & van den brug, ii. sport p sych ology: c oncepts and a pplications. new york: john wiley & sons. 1990 7. turnbull. r.. c oetzee, d., & me donald, t. r ugby fitness testing and training. pieterm aritzburg: city printing works, 1995. 8. hardy, l. sport psychology. in: colman, a .m ., & b eaum ont, j.g ., (e d s .), p sych ology survey, 1989. pp 211-231. 9. c ratty. is. p sych olog y in c ontem porary sport. 2nd ed. englewood cliffs, new j ersey: p rentice hall, 1973. 10. lazarus, r. s. e m otion and a da pta tion. new york: oxford university press. 1991. 11. kerr, j .h . a n x ie ty , a ro u sa l and s port p erform an ce: a n a pp lica tion o f r eversal theory. in : h a ck fort. d ., &. spielberger. c.d. (e d s) a n x ie ty in s ports: a n international p erspective. new york: h em isphere publishing corporation, 1989, pp 137-152. 12. kerr, j.h . sport: work or play. in: kerr. j.h ., & a pter, m. j. ( e ds) a dult p la y a m sterd a m : sw ets & zeitlitiger, 1991, p p 43-53. 13. jennings. k .e . mind in sport. k enw yn: juta, 1993. 14. ivey, a .e ., ivey, m.b.. &. simek-morgan. l. counselling and psuchotherapu: a multicultural perspective. 3rd ed. b oston : allitn b acon. 1993. 15. schomer. ii. m ental strategies and the p erception o f effort o f m arathon runners. interna tiona l journal o f sport p sych ology. 17.41-59, 1986. 16. bird, a .m .. &. cripe. b .k ., p sych ology and sport behavior. st l ouis: times mirror/mosby, 1986. 17. smith, r.e. a th le tic stress and b urnou t: conceptual m odels and intervention strategies. in: h ackfort. d., & spielberger, c. d. a n x ie ty in sports: a n intern a tion a l p erspective, n ew york. h em isphere publishing corporation. 1989, p p 183-202. 18. m asters, j. c., burish, t. g., hollon s. d ., & rimm. d. c. b ehavior therapy. new york: ifa rcou rt b race javonovich, publishers, 1989. 19. [ieil. j. p sych olog y o f sport injury, champaign. iii. : human k inetics, 1993. 20. campbell, s.s. e ffects o f sleep and c ircadian r h yth m s on performance. in: smith. a.p., & jones. d .m .(e d s), h and book o f hum an perform ance. vol 3. london: a ca d em ic press, 1992, pp. 195-216. 21. craig, a ., & cooper, r.e. s ym ptom s o f a c u te and chronic fatigue. in: smith, a.p., & jones, d .m .(e d s ), h andbook o f human perform ance, vol 3, london: a ca dem ic p ress, 1992, p p 289-339. □ 16 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiological, kinematic & psychophysical differences between overground and treadmill running s olivier, dept of human movement science, university of zululand. a b s t r a c t in order to simulate overground walking and running, the motordriven treadmill is only used in physiological, kinematic and psychophysical studies o f human emo­ tion. primarily because o f the convenience and control that it offers, the■ treadmill has played an important role in the development o f sports scien ce. and allied disci­ plines. however, the results o f studies utilising the tread­ mill can only he extrapolated to overground situations if there are no dem onstrable, significant differences between the two modes o f locomotion. this paper serves to examine the literature in order to clarify the issues involved fo r researchers. the review indicates that while the treadmill is a convenient tool to assess responses to physical work, som e caution should be applied when extrapolating certain kinds o f data obtained under cer­ tain kinds o f conditions. these might include kinematic variables at speeds in excess o f 5 m .s 1, using a treadmill fo r shoe or orthotic assessment, and fo r obtaining p sy ­ chophysical measures, which depend to som e degree on cognitive appraisal. when workloads are matched, it seem s that measures o f oxygen consumption are equiva­ lent fo r the two conditions. finally, researchers need to consider the issue o f sufficient habituation to treadmill locomotion, as this may reduce possible differences when comparing the two modes o f locomotion. in conclusion, the treadmill is a valuable tool in research investigating responses to physical work. much o f this research is how­ ever concerned with extrapolation to “real world” envi­ ronments, and researchers should be aware o f possible differences between the two modes o f locomotion under certain conditions. introduction the vast majority o f research investigating physiologi­ cal, kinematic and psychophysical responses to work appears to have been conducted in the som ewhat arti­ ficial am bience o f the laboratory. more specifically, the motordriven treadm ill is frequent ly used in biom echan­ ical and exercise physiology studies o f locomotion, as well as for training and rehabilitation purposes. t he treadmill offers man}" advantages to studies in human locomotion, mainly because o f th e control and conve­ nience it offers, particularly when doing tests that require maximal effort. using the treadmill, a familiar human m ovem ent can b e varied in intensity w hile the subject perform s in close proximity to m etabolic and cardiorespiratory recording instrum ents.12 3 a s a result, the treadm ill has played a very' important role in the study o f human movement. t h e treadm ill is often used to sim ulate overground walking and running, b ut the literature indicates a w ide address for correspondence: private bag x 10 01 , kwadlangezwa, 3886, south africa. telephone: 0351 939 16 (work & fax), 9 21963 (a /h ), 082 4525761 e-mail: solivier@pan.uzulu.ac.za difference o f opinion about the validity o f the extrapo­ lation o f treadmill information to the overground envi­ ronm ent or vice-versa4. wall and charteris2 state that even though differences between the two conditions may exist, these are probably outweighed by the conve­ nience offered by the treadmill. i f however, significant differences d o exist betw een the two m od es o f locom o­ tion, the extrapolation o f information from one environ­ m ent to th e other cou ld involve inherent inaccuracies. therefore, it is important to examine, the results o f specific studies before the results o f treadm ill studies can b e generalised to d ie field. k inematic factors initially it was thought that through a basic analysis o f fundamental m echanics, the results o f treadm ill stud­ ies could be directly applied to the overground situa­ tion. that is, in a system involving m ovem ent relative to a surface, there is no difference whether a person moves over th e surface or whether the surface moves beneath the person (except for the effects o f air resis­ tance). several investigators have however found differ­ ences in the kinematics between treadmill and over­ ground locom otion.1,50 nelson et al.1 hypothesised that meaningful differences would b e observed betw een the two conditions, indicating that different m echanics are utilised when running on the treadm ill than w hen run­ ning overground under similar conditions o f slope and speed. performance conditions for the two running sur­ faces were duplicated, and there were no differences between the m atched velocities. a t 6.4 m .s ', longer stride lengths and lower stride rates were observed for treadm ill running. t h e treadmill condition produced greater tim es o f support and corresponding decreases for non-support (table i). table i: mean results for stride length (m ), stride rate (strides.s '), support and non-support (s); for horizontal running at 6 .4 m .s 1. (table from data presented by nelson et al. 1972) stride stride support non-support length rate overground 1.92 3.32 .162 .14 treadmill 2.01* 3.1 5* .1 75* 1.43 ‘ significant (p<.01) although horizontal velocity was m atched for d ie two conditions, vertical velocity was greater for the tread­ m ill condition, indicating that running on a stationary surface requires greater vertical velocity than running on a treadmill. t h e authors concluded that the differ­ ence in velocity was m ost likely due to the acceleration deceleration pattern in overground running w hich develops during th e driving phase (acceleration) and during the touchdown and recovery phases (decelera­ tion). t hey further report that two interrelated running sports medicine november 1997 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:solivier@pan.uzulu.ac.za m odifications occur on t he treadmill. t h e runner’s foot is placed further in front o f th e centre o f gravity, and the moving b elt returns the foot beneath the runner. in overground running this would lead to a retardation of velocity. all this increases duration o f the support phase and decreases that o f th e airborne phase at a given velocity. in order for an adequate stride rate to b e maintained however, th e runner m ust com plete the recovery and touchdown phases m ore rapidly. given the variability' in vertical velocity, it was con ­ clu ded that the work done would b e greater for over­ ground than treadmill running, and that there were sig­ nificant biom echanical differences betw een overground and treadm ill running, b ut that this was particularly so in th e case o f tem poral variables. however, whether the d ifferences observed in this study are o f practical im port is still an unresolved question. elliott and blanksby5 found kinematic differences between the two conditions, but also only at higher velocities (4.82 6.2 m .s 1). for b oth m ales and females during treadmill running, stride length d ecreased and stride rate increased, w hile the period o f non-support was signifi­ cantly less. although the results o f th ese two studies were contradictory7 in that at a com m on velocity ath­ letes m odified their running style in different ways, b oth investigators indicate that at a velocity o f approxi­ mately' 5 m .s 1 or faster on the treadmill, m odifications in locom otion are likely' to occur, and th is should b e taken into account when extrapolating data to field sit­ uations. nigg et al° attem pted to determ ine w hether a tread­ mill can validly b e used as an instrument to simulate the kinem atics o f human locom otion (luring overground running. specifically', leg kinematics were quantified for treadm ill running by varying the treadmill gradient, the running velocity, the shoe, and the experience with treadmill running and were com pared with th e corre­ sponding values for overground running. they found that m ost o f th e lower extremity' kinem atic variables show ed inconsistent trends for individual subjects, with the differences being substantial. contrary' to expectations, they found that an increase in running speed tended to decrease the kinematic differences, and that a larger, more powerful treadm ill increased the differences. it must however b e rem em bered that th e number o f subjects used to assess these questions was sm all (n=22) and the variance associated with the variables was quite high. in stressing the importance o f treadmill habituation b efore extrapolating to over­ ground conditions, and noting particular adaptations to treadm ill locom otion, th e authors concluded that indi­ vidual assessm ents o f running kinem atics on a tread­ m ill for sh oe or orthotic assessm ent may possibly lead to inadequate conclusions about overground running. physiological factors frishberg8 exam ined selected kinematic variables dur­ ing overground and treadm ill sprinting to determ ine possible physiological differences, as well as differ­ ences in running technique due to altered kinematic variables. h e found that 0 2 debt for th e overground condition was 36% greater than for the treadm ill run­ ning condition. pugh7 has proposed that at running velocities above 6 m .s 1, air resistance m ight b e respon­ sible for such differences. t h e reported 36% increase in 0 2 d ebt however, far exceeds other reports o f the p er­ centage cost o f air resistance to energy' expenditure, and as such the large difference cannot b e accounted for purely by' the air resistance factor. frishberg’s3 k ine­ m atic analy'sis revealed a p ossible standardisation o f running form during treadm ill locom otion, and h e con ­ cluded that h is data suggested that overground and treadmill locom otion at high sprinting speeds are bio mechanically different, and that this resulted in the significant difference in oo debt. h e hypothesised that the moving treadmill b e lt reduces th e energy require­ ments o f locom otion by' moving the supporting foot and lower leg backward, which may contribute to the observed greater range o f angular m otion displayed by the lower leg, as well as the reduced angular m otion o f the thigh during the support phase. t h ese changes, he concluded, would probably result in a reduced w ork­ load for the hip musculature, thus requiring less ener­ gy expenditure for the treadm ill running condition. thus, according to this study', treadm ill sprinting is not as phy'siologically stressful as overground running. m eth od olog ica l p rob lem s w ith speed -m atch in g betw een the two sprinting conditions however indicate that f rish bergv results should b e interpreted with caution. the validity o f using 0 2 d ebt to m easure total energy' expenditure is also questionable. furthermore, the velocity differences between h is and other studies makes com parison difficult. mcmiken and danieis" measured v 0 2, in a discrete series o f three speeds and at maximal effort during treadm ill and track running. t h e aerobic requirement differences were evaluated, and none o f the differences were foim d to b e significant. t h e authors concluded that i f real aerobic differences d o exist between the two conditions, then they are probably very' small. they con ­ clu ded that treadm ill determinations o f oo uptake may b e validly extrapolated to track running in calm air. however, the running speed o f subjects in this study' never exceeded 4.3 m .s 1, and differences may' occur at higher velocities. in support o f these results, bassett et al!) state that there is general agreement that the oxy­ gen dem and o f level running is similar for both the treadmill and overground situations at speeds under 4.5 m .s 1. as stated earlier, pugh7 reported a greater energy' cost for track running, but this was attributed to the effects o f air resistance rather than to fundamental differences in the m echanics o f overground and tread­ mill locom otion. t h e question o f w hether real aerobic differences d o exist between th e conditions remains unanswered, but at present the treadm ill appears to b e a valid instrument for th e estim ation o f oxygen uptake when the data are to b e applied to track running in calm air at running speeds b elow 4.5 m .s 1. m ost o f the above studies were, however, conducted on level surfaces, and the issue o f grade locom otion is an ergonom ic problem that is far from resolved10. a ccording to acsm 11 prediction formulae, the energy' cost for overground running is greater than for running on the treadmill. a t a speed o f 3.3 m .s 1 and at 7.5% grade, th e difference would amount to 10.25 m l.kg-1 min-1. conversely, van lngen schenau'* used a theoreti­ cal physics approach and concluded that there should b e no d ifferen ces betw een th e m eta b olic energy requirements o f inclined treadm ill running and over­ ground hill running. i f differences do exist, van lngen schenau4 feels that they can b e attributed to visual, and to a lesser extent, auditory' factors. bassett et al!) report date which support th ese assumptions. at 0% and 5.7% grades, no significant d iffe re n ce s w ere ob served between overground and treadmill running. t h ese con ­ clusions are supported by the research o f olivier and s cott12 (table ii), who found no differences in v 0 2 for a grade running task on the treadm ill and overground. minute ventilation (ve) and psychophysical differences between the two conditions were attributed to cognitive 18 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) appraisal o f the particular work task. visual informa­ tion may b e important in maintaining equilibrium and stability, w hile the am bience o f the treadmill and labo­ ratory could prove to b e an extremely stressfid environ­ ment for a subject. these factors together with wand resistance could cause differences betw een the two sit­ uations, but it appears that measurements o f voo obtained during level and inclined treadmill are valid when applied to the overground situation. psychophysical factors with regard to possible psychophysical differences, an examination o f several studies indirectly related to the problem wall b e useful. utilising a parallel-processing perspective, pennebaker and lightner1-' dem onstrated that during exercise, external cues (e.g. terrain) do com pete w'ith internal cues e.g. ventilation) specifi­ cally, despite no differences in fatigue ratings, subjects w êre found to run faster on a cross-country course than on a track. a s fatigue reports were com parable for the two courses, it w'as hypothesised that shifting attention to external cues led to dim inished responsivity to inter­ nal states.14 put another wav, as subjects were focusing on external cues to a high degree on the cross-country course, their processing o f internal sensations w'as restricted.1" an investigation by stones1" provides som e support for the limited capacity position described by r ejeski.17 stones10 states that physiological control sys­ tems undoubtedly contribute to judgem ent o f pace and fatigue, and it w'ould b e surprising i f the visual system d id not contribute also, at least to pace judgem ent. consequently, h is research w'as designed to increase the dem and on a runner’s visual system by restricting field o f vision through the use o f specialised goggles. attenuated visual input resulted in: a) enhancem ent o f perceived pace relative to actual pace, b ) lessening o f fatigue relative to actual pace, and c) slowing o f actual pace. t h ese findings make it apparent that the visual system , in addition to other physiological control sys­ tems, contributes to various aspects o f th e running experience. t h is raises an interesting question w'ith regard to running environment and fatigue perception; namely, m ight parallel observations b e obtained under conditions w'here visual input was not attenuated artifi­ cially'? in other w'ords, would runners on a treadmill report different perceptions o f fatigue than w'hen run­ ning outdoors at a similar p a ce? it is w'orth noting that under conditions o f unrestricted vision, the visual field is filled both with near and far objects. for a person in m otion, th e corresponding retinal projections wall th erefore b e associated writh varying d eg rees o f change.10 t h is may not b e the case for treadm ill run­ ning. stones16 thus found that visual impairment and the subsequent vigilance required for m ovem ent result­ ed in reduced aw'areness o f fatigue-relevant physiologi­ cal information. thus, according to this particular investigation, it w'oidd appear that w'hat is available in perception can b e b locked from consciousness by flood­ ing the lines o f conummication wath distracting stimuli. birk and b irk‘“ contend that the use o f eatings o f perceived exertion (rpe), estim ated during exercise testing, to control intensity during training by repro­ duction o f similar efforts, may b e inappropriate. they feel that environment influences would render direct perceptual translations from the laboratory' to the field invalid. jackson et al19 have dem onstrated that the physiological and psychological correlates o f exercise perform ance are different in a field setting than in the laboratory'. on the other hand, ratings o f perceived exertion w'ere not affected by auditory input such as m usic and m echanical noise, e.g. treadmill operation.-0 it is w'orth noting that studies o f til l is nature are d iffi­ cult to control, and may not validly discrim inate between d ie effects o f physiological and psychological stress indicators, as has b een inferred.20 nevertheless, in the field, w'here a myriad o f social physiological forces impinge on the performer, the role o f physiologi­ cal feedback to rpe may well be reduced. the potential role d iat motivational and informational factors may play in the subjective assessm ent o f physical w'ork is d iu s increased.14 this is supported by olivier & scott12 (table ii), w'ho investigated physiological (hr, v 0 2, ve), perceptual (rpe ) and attitudinal (sem antic differential) responses to identically m atched w'ork loads (70% o f voo max) under treadm ill and overground conditions. there w'ere no differences in v 0 2 and hr responses, w'hereas ve and rpe responses w'ere signif­ icantly elevated for the treadmill condition, and atti­ tudes w'ere m ore favourable tow'ards the overground condition. in support o f d ie literature cited above, the audiors concluded that d ie differences w'ere, at least in part, due to the perceptual and cognitive interpretatable ii: mean physiological, rpe and attitudinal responses to uphill (5.72% ) overground and treadm ill nm ning at 2.94 m .s-1. (table from data presented by olivier & scott, 1993). variable overground treadmill physiological h r (b .m in 1) 157 156 v 0 2 (ml.kg ‘ .ruin1) 47.59 48.45 ve ( l . mi u 1) 69.05 75.13* rpe local 11.07 11.96* central 10.86 11.36 overall 10.89 11.82* attitudes evaluation 26.53 16.73* potency' 16.64 13.91 activity 18.27 16.81 overall 61.46 46.82* ‘ significant (p<.05) tions o f d ie particular characteristics inherent in the two environments. treadmill accom m odation treadm ill accom m odation has been defined as the state obtained w'hen a subject has had sufficient training on the treadm ill, such that no significant wathin-day or between day kinem atic or temporal differences are evi­ dent from stride-to-stride. t h e p rocess involves the gradual establishm ent o f a stable and essentially nor­ mal gait showong no significant variations in averaged kinematic patterns from stride-to-stride or trial-to-trial over days or w'eeks. a ccom m odation is contingent upon initial adjustment and subsequent long-term condition­ ing.21 wall and charteris21 have dem onstrated that d ie kinematics o f treadmill locom otion alter as the novice learns how' to w'alk on th e moving b elt surface. although accom m odation to the surface may initially b e rapid, ldnem atic changes continue tow'ards a stable gait pat­ tern w'ith distributed practice over a period o f 1 horn-.2 sports medicine november 1997 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) these authors have also suggested that there may b e m etabolic correlates o f these progressive changes, and that changes in skill level may result in a lowering o f the energy cost o f gait as th e novice becom es an accom ­ p lish ed treadmill walker. furthermore, they recom ­ m end that when studies to investigate (lie subtle differ­ ences between overground and treadm ill locom otion are contem plated, it would b e inappropriate to em ploy sub­ je cts habituated for anything less than 1 hour, in sever­ al distributed practice sessions, and that m easure­ m ents should not b e taken daring d ie first 2 minutes o f performance. s ch ielr2 states that the actual tim e required before the individual feels com fortable with d ie treadmill seem s to d epend on factors such as lengdi o f tim e into th e treadm ill run and overground running experience, w hile van lngeii schenau4 feels that psychological fac­ tors such as apprehension may retard accom m odation. therefore when d ie treadmill is used to derive cardio­ vascular measures in order to assign a subject’s work­ load to the overground situation, it is important to expose the subject to an adequate amount, o f treadmill locom otion,22 otherw ise inaccurate or m isleading infor m adon may result. investigating d ie problem o f treadm ill accom m oda­ tion, schleb22 found that significant between-day kine­ matic adjustments were m ade by novice treadmill run­ ners, but only betw een days 1-2 o f a 10-day (15 min per day) training programme. further, significant within day adjustments were only evident between m inutes 1 & 8 on any day’s run, and not after minute 8. within day differences were not found beyond d ie third day, indi­ cating fairly rapid accom m odation to treadmill locom o­ tion. from this he concluded tiiat one 15 mill training ses­ sion is inadequate for a novice treadmill subject to accom m odate fully, but tiiat after th e 8th min o f a sec­ ond habituation session a subject should be accom m o­ dated to the treadmill. wall & charteris22 however sug­ gest that where measurements are to b e m ade o f gait patterns for th e purpose o f application to overground situations, subjects should be previously habituated in distributed practice sessions for 1 hr, and no m easure­ m ents should b e m ade within th e first 2 min o f perfor­ mance. further, in studies investigating subtle differ­ ences betw een treadm ill and overground conditions, it is inappropriateto utilise subjects habituated for any­ thing less than 1 hr in several distributed .practice ses­ sions. however, when fine measures o f gait are not co l­ lected, random speed and grade habituation o f 10 min should suffice.2 conclusion in conclusion, the treadmill is a convenient tool to assess responses to physical work. in terms o f its prac­ tical application as a research tool, it is widely used to extrapolate to overground locom otion contexts. the research reviewed above however indicates that som e caution should b e applied when extrapolating certain kinds o f data obtained under certain kinds o f con d i­ tions. t hese m ight include kinematic variables at run­ ning speeds in excess o f 5 m .s 1, using a treadmill for sh oe or orthotic assessment, and psychophysical m ea­ sures such as rpe and attitudinal responses, which d epend to som e degree on cognitive appraisal. there seem s to b e general agreement that m easures o f oxygen consumption are equivalent for both conditions when workloads are m atched. sufficient habituation to tread­ m ill locom otion on the part o f research participants may reduce the kinematic and psychophysical differences betw een the two conditions, with a consequent increase in the validity o f applying the data to field situations. references 1. nelson rc, dillman cj, lagasse p & brlcket p (1972) biomechanics o f overground versus treadmill running. medicine & science in sports 4 ( 4 ) , 233-240. 2. wall jc & charteris j (1981) a kinematic study o f long­ term habituation to treadmill walking. ergonomics 2 4 (7 ), 531-542. 3. frishberg ba (1983) an analysis o f overground and tread­ mill sprinting. medicine & science in sports & exercise 1 5 (6 ), 478-485. 4. van lngen schenau gj (1980) some fundamental aspects o f the biomechanics o f overground versus treadmill locomo­ tion. medicine & science in sports & exercise 1 2 (4 ), 257 261. 5. elliott bc & blankshy b a (1 976) a cinematographic analysis o f overground and treadmill running by males and females. medicine & science in sports 8 ( 2 ) , 84-87. 6. nigg bm, de boer r w & fisher v (1995) a kinematic comparison o f overground and treadmill running. medicine & science in sports & exercise 2 7 (1 ), 98-105. 7. pugh lgce (1971) the influence o f wind resistance in run­ ning and walking and the mechanical efficiency o f work against horizontal or vertical forces. journal o f physiology 213, 255-276. 8. mcmiken df & daniels jt (1 976) aerobic requirements and maximum aerobic power in treadmill and track run­ ning. medicine & science in sports 8 ( 8 ) , 14-17. 9. bassett dr, giese md, nagle fj, ward a, raab dm & balke b (1 985) aerobic requirements o f overground versus treadmill running. medicine & science in sports & exercise 1 7 (4 ), 477-481. 10. charteris j (1986) pedestrian adaptations to differences in the slopes o f walking surfaces. proceedings o f the second annual conference o f the ergonomics society o f southern africa, university o f cape town. 11. american college o f sports medicine (1980) guidelines for exercise testing and prescription. 2nd edition, lea & febiger, philadelphia. 12. olivier s & scott pa (1993) physiological, perceptual and attitudinal responses to identically matched workloads in field and laboratory testing conditions. s71 journal for research in sport, physical education &recreation 1 6 (1 ), 63-72. 13. pennebaker j w & lightner jm (1980) competition o f internal and external information in an exercise setting. journal o f personality & social psychology 39, 165-174. 14. rejeski wj (1981) the perception o f exertion: a social psy chophysiological integration. journal o f sport psychology 198 1 (4 ), 305-320. 15. hardy cj, hall eg & presthoklt p h (1986) the media tional role o f social influence in the perception o f exertion. journal o f sport psychology 8, 88-104. 16. stones a (1980) running under conditions o f visual input attenuation. international journal o f sport psychology 1 1 (3 ), 172-179. 17. rejeski wj (1985) perceived exertion: an active or passive process? journal o f sport psychology 1985, (7 ), 371-378. 18. birk tj & birk ca (1987) use o f ratings o f perceived exer­ tion for exercise prescription. sports medicine 4, 1 -8. 19. jackson a , dishman rk, la croix s, patton r & weinberg r (1981) the heart rate, perceived exertion and pace o f a 1.5 mile run. medicine & science in sports & exercise 13, 224-228. 20. carton rl & rhodes ec (1 985) a critical review o f the lit­ erature on ratings scales for perceived exertion. sports medicine 2, 198-222. 21. wall jc & charteris j (1 980) the process o f habituation to treadmill walking at different velocities. ergonomics 2 3 (5 ) , 425-435. 22. schieb d a (1986) kinematic accommodation o f novice treadmill runners. research quarterly for exercise & sport, 5 7 (1 ), 1 -7. 23. charteris j (1 9 8 7 ) personal communication. rhodes university, grahamstown, south africa. i i 20 sports medicine november 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license ‘i’m doing it for myself’: using a smartphone-based exercise service during the covid-19 lockdown in the faculty of health sciences, university of the witwatersrand, south africa g torres, phd; n neophytou, msc med; p fourie, bhsc (hons), x buntting, bhsc (hons); d constantinou, mbbch, msc med, mphil (fims); pj-l gradidge, phd centre for exercise science and sports medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: g torres (georgia.torres@wits.ac.za) the benefits of physical activity (pa) in general, in confinement and during pandemics, has previously been reported and is still relevant during the current wave of the global coronavirus 2019 (sars cov-2) (covid-19) pandemic.[1] south africa’s response to the pandemic was rapid and stringent, limiting national economic activity and movement of people. this approach was supported nationally and was particularly important as the health sector prepared for the upswing of the disease’s presence in central ‘hot-spots’, such as city centres and environments with populations living in crowded settings. sports participation, access to gyms and fitness facilities were prohibited during the lockdown, resulting in limited options for pa and exercise, and therefore concerns regarding rising inactivity levels. emerging evidence; nevertheless, advocated for continued pa to maintain optimal cardiometabolic and immune health during the pandemic,[2] while other data support obtaining sufficient pa to prevent poor disease outcomes in those individuals contracting covid-19, compared with that of matched sedentary patients.[3] homebased exercise for cardiac rehabilitation and maintaining health is now a focused area which was promoted before countries introduced lockdowns.[4] smartphone pa mobile apps and activity trackers have been used pre-covid and their applicability during the covid-19 pandemic is self-evident. sensors in smartphones and activity trackers enable users to easily access pa programmes and monitor physical activity levels remotely via automated and continuous self-monitoring and feedback. a recent metaanalysis investigated the effect of activity trackers and mobile apps with the features mentioned above in increasing physical activity in healthy adults (18–65 years old).[5] the meta-analysis found that mobile app and tracker users were more active than control groups by an average of 1 850 additional steps per day. the interventions reviewed in the meta-analysis included a variety of smartphone apps and activity trackers, as well as other components of engagement, such as emails, human involvement via phone calls or face-to-face meetings, and text messaging. furthermore, interventions studied included different behaviour change techniques (e.g. ‘feedback and monitoring;’ ‘rewards and threats’). importantly, the metaanalysis highlighted that the apps and trackers that were complemented by human personalisation or text-messaging were significantly more effective. the offer of the smart-phone pa application (in circulation since 2008) was based on the quick implementation of the lockdown and the immediate need for staff members to have background: sufficient physical activity (pa) lowers poor health outcomes, with data showing these protective effects in populations under varying levels of lockdown during the covid-19 pandemic. the advent of online pa programmes has created novel opportunities to offset the deleterious effects of inactivity. however, data are limited and the readiness and acceptance of such technology is unknown. these authors nevertheless noted an opportunity to investigate this approach based on promising emerging data at the time of the hard lockdown in south africa. objective: this exploratory study investigated the engagement and perceptions of a smartphone application to promote health and fitness in a sample of employees at a south african university. methods: employed members of staff (n=15) of the university of the witwatersrand were recruited through email invitation during the hard level 5 covid-19 lockdown in 2020. individualised home-based pa programmes were prescribed through a mobile application for a period of eight weeks. researchers qualified in biokinetics provided online supervision of the exercise sessions during the intervention. participants were asked to complete a self-reported questionnaire about their use of the application. thematic analysis was used to understand these responses. results: lack of motivation was perceived to have a negative effect on participation in the online pa programme. only one participant reported using the mobile application consistently during the study period, while half of the participants reported having trouble with the usage of the application. the participants frequently mentioned the need for technical support and further engagement from the clinicians supervising the pa programme to ensure use and progression. staff identified issues with connectivity and already having too many phone applications (apps) amongst the reasons for the technical difficulties. conclusion: this study demonstrates the challenges and potential for the uptake of online pa interventions during covid-19 and, despite its small sample size, the data provide important lessons learned that will be used as information in further investigations. keywords: physical activity, home-based exercise, compliance s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a9053 mailto:georgia.torres@wits.ac.za http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9053 https://orcid.org/0000-0002-0197-4718 https://orcid.org/0000-0002-3363-7695 https://orcid.org/0000-0002-0085-2970 https://orcid.org/0000-0002-4060-6811 https://orcid.org/0000-0002-0050-3201 https://orcid.org/0000-0001-5225-1184 original research sajsm vol. 33 no. 1 2021 2 an option of exercising during this period. the intention of this study was to offer a mobile app that could be used to access pa home-based programmes and learn this information from the users of the smartphone application. methods participants the wits metro wellness gym (wmwg) at the centre for exercise science and sports medicine, university of the witwatersrand (wits), in the city of johannesburg, offers sports medicine and exercise science services to employees of the faculty of health sciences and the general community. current facility members and faculty staff were offered a pa solution when the facility closed and the covid-19 lockdown began in south africa. procedures ethical clearance for the study was received from the wits human research ethics committee (medical) (certificate m200843). the targeted population was invited via email to download the mobile application. the application offered a daily ‘workout of the day (for home)’ of easy, medium, or high intensity levels. the mobile application was connected to a cloud platform that allowed biokineticist staff to assign, record and track pa. participants could also connect a third-party device (e.g. wearable fitness devices) to the application and record all activity/exercise. biokinetics staff could connect with the members weekly via the ‘coach’ section on the mobile application that facilitates messaging between the health professional and participant. the biokineticist was able to track pa levels on the online platform and send ‘nudges’ and ‘cues’ to participants. this could only be done with participants who engaged with and downloaded the mobile application. therefore, not all participants were ‘coached’ during this study intervention. questionnaire a questionnaire link was sent to participants for completion and to provide data to understand the use of the technology. self-reported pa levels were calculated using a physical activity index (pai). the pai is a non-exercise equation[6] consisting of three components: frequency, amount, and intensity of pa. the product of the variables categorises pa as (i) low, (ii) moderate or (iii) high. statistical analysis descriptive statistics were conducted for the quantitative portion of the analysis and reported as mean (+sd), or median (interquartile range (iqr)) for skewed data. statistica version 13.5 (tibco, usa) was used to perform the quantitative analysis. thematic analysis was conducted manually to determine the themes for the qualitative component. the themes with participant responses were reported verbatim. two of the researchers (pjg and gt) determined the themes and reached consensus. results one hundred and fifty-six individuals downloaded the mobile application although not all continued engaging with the app. only fifteen participants completed the questionnaire, with a median age of 49 (59) years, mean weight (±sd) of 72.4 ± 15.4 kg, and 67% (n=10) were females and 33% (n=5) were males. a single participant (n=1, 6.7%) reported using the mobile application regularly during the hard lockdown, while 47% (n=7) did not. twenty percent (n=3) reported the application as being user-friendly while 20% reported difficulty in using the technology. a similar pattern was observed for the remainder of questions, with some participants commenting about receiving inadequate technical support (n=3, 20%). pa activity levels during the first two weeks of lockdown were similar to those before lockdown (n=12, 80%) and the levels during weeks three to five of lockdown were similar to those before and during lockdown (n=11, 73%). pa levels during weeks six to eight of lockdown were similar to those before and during lockdown (n=12, 80%), and finally, pa activity levels increased progressively during the lockdown (n=9, 60%). the same number of participants agreed and disagreed (i.e. 13% for each) that the exercises were updated and they progressed throughout the lockdown. only one participant showed data on the cloud-based platform of tracking and recording of workouts via the mobile application. thus, no analysis was performed on this data. through thematic analysis of open-ended questions, the following four themes emerged from the participants’ responses on engagement with the mobile application: motivation, support, usability and technical. the verbatim quotes accompanying the themes can be found in the text in italics. sixty-nine responses were observed. motivation most of the responses were linked to the motivation theme (33/68). slightly over a third (12/32, 38%) responded to having been motivated to engage in pa through the mobile application.  ‘new workouts were available daily’  ‘yes. made a schedule’  ‘home exercises’  ‘it helped to establish motivation’  ‘as no one else in my family does physical exercise, it was hard to do it on my own, while they watch, but i realised later that i’m doing it for myself, and no one else’  ‘it helped to have been able to start walking outside again’  ‘have some home workout equipment’ in contrast, more participants (21/32, 66%) responded that they were not stimulated to exercise during the lockdown.  ‘no. no one to train with and enjoy equipment’  ‘lack of motivation and equipment’  ‘the cold and lack of motivation’  ‘gym being closed’  ‘missed the engagement with others’  ‘appreciate the initiative, but it’s not for me’ original research 3 sajsm vol. 33 no. 1 2021  ‘i haven’t really had the motivation’  ‘boredom, used to regularly attend gym’ support some participants reported that there was insufficient support to assist them with physical activity during the lockdown (4/68).  ‘was not given to me’  ‘never used prefer free flowing exercises’  ‘not preferable to me’  ‘i could not find videos on the app relevant to my gym plan’ usability twelve of the responses corresponded to the usability of the mobile application. fifty percent (6/12) stated that the application was user-friendly.  ‘the app made it easier for programs to do’  ‘easy to use’  ‘it’s good’ the other half of the responses were aligned with not engaging and with difficulty in using the application (6/12).  ‘haven’t been using the app, therefore i cannot offer a response’  ‘needs to be more flexible/user-friendly’  i did not use the app as i struggled to set it up’ technical a fifth (14/68, 21%) of the responses concerned the technical or preference aspect of the application, suggesting the need for technical support.  ‘does not link to discovery (reward medical health scheme)’  ‘phone/data issues’  ‘not tech savvy’  ‘between insurance companies, banking, email, fitness trackers, social media and other important apps, it is not practical to download yet another one’  ‘it takes up space on my phone and i am not interested’  ‘prefer my regular apps’ other responses were also considered valuable in understanding participant usage of the application, but were not placed into themes (5/68).  ‘other commitments’  ‘injury’  ‘to some extent. i had an arthroscopy eight weeks into lockdown and am now recovering’ discussion this study found that the uptake and engagement with the pa app, even though considered user-friendly, was low, with only 6.7% stating that they used the mobile application. the low adherence to pa smartphone applications has been confirmed. [7,8] mollee et al. reported 74 % of health app users stopped using an app within ten times of use, and 26 % of health apps were used only once after being downloaded. [8] a review by yanga et al. aimed to synthesise the factors influencing pa mobile application adherence and to identify directions for future research in this area.[7] the evidence indicated that 89 distinct factors influenced pa app adherence. these factors were classified into three categories: personal factors (user-related), technology features (app-related) and contextual factors (environmental-related). subcategories for personal factors included demographic and socioeconomic factors (e.g. age, gender), psychological factors (e.g. attitude toward the app-based pa intervention) and health-related factors (e.g. stress, depression). others were predefined goals (e.g. a goal to quit smoking) and benefits sought (e.g. hedonic motivation). subcategories for technology features were user experience (e.g. perceived playfulness) and functions (e.g. pa tracking). contextual subcategories were related to the technical context (e.g. concerns about data privacy) and social context (e.g. community of users). studies assessing the causality between factors and pa app adherence are rare. understanding the factors that influence pa app adherence provide guidance for app-delivered pa interventions and could explain the results of this study. table 1 highlights some factors that could explain the low app adherence of this study. many of the participants in this study reported decreased levels of pa when compared to the pre-lockdown period. as with the findings in this study, other studies have also shown a decrease in pa in adults because of lockdowns.[9, 10] ding et al.[11] found that in developed countries, community interest in exercise surged immediately following the lockdown, peaked within the first two weeks, then declined but remained at a higher level than before the lockdown. this indicated that despite challenges to an active lifestyle, the covid-19 lockdown may have led to increases in population-level interest in pa. it is important to acknowledge though that the interest in exercise may not translate into behavioural change. only 20% of the participants in this study found the mobile application beneficial with respect to exercising during lockdown. technical issues, support and motivation were cited as reasons for not using the technology. one cannot differentiate the underlying reasons for lack of motivation or assign this to the app use or any other reasons. further, these authors cannot determine whether the opportunity to use the app had any influence on the number of reasons given. the availability of exercise programmes on the mobile application was cited as a reason for those using the technology, suggesting that there was a benefit for some participants. as mentioned. table 1 highlights some factors that could explain the low adherence and engagement with the pa app used in this study, based on available research. the researchers of this study are not aware of other studies that have investigated the use of mobile application technology and pa levels during the lockdown phase of the covid-19 pandemic. this study indicates that technology alone may not be sufficient to influence pa levels during a lockdown, but it appears to have some value. individuals using such technology appear to need the motivation and support of a health and fitness professional, or a place where exercise can be undertaken to maintain pa levels. original research sajsm vol. 33 no. 1 2021 4 personal factors included demographic and table 1. factors influencing physical activity (pa) app adherence in relation to results of this study factors* comments applicable to this study’s results personal factors demographic and socio-economic age research has indicated that older individuals had higher adherence. gender males have shown higher app adherence than females. income having higher income was associated with higher adherence. this study could not account for this factor. household type living with single parents has been associated with lower adherence. this study did not have access to household type information. psychological factors positive attitude toward the intervention a positive attitude increased adherence. attitude towards to the offer of the intervention was not assessed. instrumental attitude app adherence increases if the person believes that it is smart to use the app and be physically active. this was not assessed in the study. experiential attitude app adherence increases if the person believes the app is fun and the advantages outweigh the disadvantages. this was not assessed in the study. attitudes towards health and fitness this factor may be associated with app adherence but these attitudes were not investigated in the study. not liking aspects of the app the participants of this study did not report not liking any aspects of the app. thus, this factor was unlikely to be associated with the low adherence to the pa app intervention of this study. health-related factors self-rating general health positively associated with adherence. not applicable to this study’s results. regular app use prior positively associated with adherence. not applicable to this study’s results. depressive symptoms negatively associated with adherence. depression levels were not measured in this study. depressive symptoms though have been associated with lockdown and may have contributed to the low app adherence of this study. concern about health positively associated with adherence. not applicable to this study’s results. smoker status positively associated with adherence. not applicable to this study’s results. pre-defined goals goal to quit smoking lack of this goal was associated with higher adherence. this study did not investigate participants’ goals. benefits sought personal benefits positive associations have been found with this factor and app adherence. this factor was not assessed in this study. hedonic motivations positive associations have been found with this factor and app adherence. this study’s questionnaire did not address this factor. epistemic benefits positive associations have been found with this factor and app adherence. not applicable to explaining this study’s results. social integrative benefits (-) positive associations have been found with this factor and app adherence. this factor was mentioned in the participants’ responses. app-related motives positive associations have been found with this factor and app adherence. not applicable to this study. technology features user experience perceived playfulness the study did not assess this feature. effort expectancy the study did not assess this feature. lack of interest (-) participants did cite this factor as a reason for not engaging. time cost (-) participants did cite this factor as a reason for not engaging. self-efficacy the study did not assess this feature. ease of use (-) some participants did have difficulty using the app. accurate consistent data this is a feature of the app used in the intervention. pleasurable workouts participants did find the workouts in the app used in the study, beneficial. experience the experience of the app was not interrogated. original research 5 sajsm vol. 33 no. 1 2021 lessons learned the following considerations are possible for such a pa app service to be undertaken based on the factors that influence pa app adherence:  making a pa application freely available does not ensure that individuals will engage with the technology.  a better understanding is needed from the personal, technology and contextual characteristics of the participants with whom the pa app intervention is implemented. it is recommended that an initial (even virtual) meeting with a health and fitness professional is used to gather this information.  the motivations of and the benefits sought by the participants also need to be understood when implementing a pa app intervention.  the coaching process needs to be set up as part of the intervention. personalised health-specific text messaging and a pa target/goal setting should accompany a pa app intervention. the intervention should also involve the coach sending frequent goal setting text message reminders.  the intervention design needs to consider a team-based approach.  attitudes of participants towards the pa app intervention (experiential and instrumental) and towards health and fitness should be assessed prior to offering the intervention.  there may also be a need for developing a user’s positive attitude towards the pa app and informing them of the benefits they can derive from its use as part of the intervention.  factors under technology features are useful for pa app developers or pa intervention designers. limitations  tracking on the application is dependent on participants submitting pa exercises performed. participants may have exercised but did not record sessions.  connection to a gps/heart rate device would give the most accurate, objective recording of activity data. this was not possible to do within the constraints of this study.  a minimal number of participants engaged with the mobile application and thus most participants were not “coached” or “nudged” for a response to their app. the important effect of pa behaviour modification could thus not be applied or assessed.  the small number of participants in the study. conclusion this study demonstrated that reported pa levels decreased during the hard lockdown and offering clients a web-based pa table 1. factors influencing physical activity (pa) app adherence in relation to results of this study (continued) technology features functions pa tracking this was a feature of the app used in the intervention. pa goal/target setting this was a feature of the app used in the intervention. progress monitoring this was a feature of the app used in the intervention. visual/auditory cues the app used in this intervention had these as part of the technology. game-like rewards (-) some participants did report the lack of rewards as a reason for not using the app. coaching features (-) coaching support was positively associated with app adherence. this factor was mentioned by the participants. the pa app used in this intervention had coaching features but they were not used. social support the research was equivocal with regards to this factor. personalisation this feature was available on the app used in the study. prompting by the app (-) this was not available with the app used in the study and may have contributed to the low adherence goal-setting text message reminders (-) the app used in the study had the ability to do this via the coach application, but it was not implemented in the study. gamification not available on the app used in the study. push notifications containing a tailored health message (-) this was not available with the app used in the study and may have contributed to the low adherence customisation of exercise this feature was available on the app used in the study. contextual factors technical context data privacy this was not cited as negative factor by the participant of the study. technical problems (-) this was a negative factor reported by some participants. social context community of users not applicable to this study. team condition (-) this factor has been cited as having a causal relationship. our intervention did not have a team component set-up. * factors were taken from yang et al. [7] (-); may have contributed to the lack of adherence to the pa app intervention. original research sajsm vol. 33 no. 1 2021 6 tracking and optimising technology must be supplemented with further coach-client interaction to ensure effective maintenance of pa and exercise at home or during a lockdown. the study’s findings demonstrate that the participants seek further guidance with pa guidelines and support with using the technology, indicating opportunities for evidence-based counsel and supervision by appropriately qualified healthcare professionals. given that the emerging evidence demonstrates an upsurge of psychological stressors during the covid-19 pandemic[12], the authors recommend urgent pa rehabilitation and intervention to address mental health concerns in survivors of the disease and populations at risk. further research is required to determine the most effective exercise regimens for individuals during lockdowns or for home-based programmes. conflict of interest and source of funding: the authors declare that they have no conflict of interest. pjg is supported in part by the south african nrf through grant number 113366. any opinion, finding and conclusion or recommendation expressed in this material is that of the author(s) and the nrf does not accept any liability in this regard. acknowledgements: the authors acknowledge the participants involved in the study. author contributions: gt, nn, dc and pjg conceptualised the study design and authored the paper. xb and pf collected the data. gt and pjg analysed and interpreted the data. all authors approved the final version of the manuscript. references 1. simpson rj. exercise, immunity and the covid-19 pandemic. available from: https://www.acsm.org/blogdetail/acsm-blog/2020/03/30/exercise-immunity-covid-19pandemic. cited 19 october 2020. 2. chowdhury r, van daalen kr, franco oh. cardiometabolic health: key in reducing adverse covid-19 outcomes. glob heart 2020;15(1):58. [https://doi.org/10.5334/gh.879] 3. chen p, mao l, nassis gp, et al. coronavirus disease (covid-19): the need to maintain regular physical activity while taking precautions. j sport health sci 2020;9(2):103-104. [https://doi.org/10.1016/j.jshs.2020.02.001][pmid: 32099716] 4. thomas r, beatty al, beckie tm, et al. home-based cardiac rehabilitation: a scientific statement from the american association of cardiovascular and pulmonary rehabilitation, the american heart association, and the american college of cardiology. circulation 2019; 140(1): e69-e89. [https://doi.org/10.1161/cir.0000000000000663][pmid: 31082266] 5. laranjo l, ding d, heleno b, et al. do smartphone applications and activity trackers increase physical activity in adults? systematic review, meta-analysis and metaregression. br j sports med 2021; 55(8): 422-432. [https://doi: 10.1136/bjsports2020-102892] [pmid: 33355160] 6. kurtze n, rangul v, hustvedt b-e, et al. reliability and validity of self-reported physical activity in the nordtrøndelag health study: hunt 1. scand j public health 2008;36(1):52-61. [https://doi.org/10.1177/1403494807085373] [pmid: 18426785] 7. yang x, ma l, zhao x, et al. factors influencing user’s adherence to physical activity applications: a scoping literature review and future directions. int j med inform 2020;134:104039. [https://doi.org/10.1016/j.ijmedinf.2019. 104039] [pmid: 318650054] 8. mollee js, middelweerd a, te velde sj, et al. evaluation of a personalized coaching system for physical activity: user appreciation and adherence. in: pervasivehealth '17: proceedings of the 11th eai international conference on pervasive computing technologies for healthcare may 2017: 315–324. [https://doi.org/10.1145/3154862.3154933] 9. ammar a, brach m, trabelsi k, h c. effects of covid-19 home confinement on eating behaviour and physical activity: results of the eclb-covid19 international online survey. nutrients 2020;12(6):1583. [https://doi.org/10.3390/nu12061583] [pmid: 32481594] 10. giustino v, parroco am, gennaro a, et al. physical activity levels and related energy expenditure during covid-19 quarantine among the sicilian active population: a crosssectional online survey study. sustainability 2020;12(11):4356. [https://doi.org/10.3390/su12114356] 11. ding d, del pozo cruz b, green ma, et al. is the covid-19 lockdown nudging people to be more active: a big data analysis. br j sports med 2020; 54(20): 1183-1184. [http://dx.doi.org/10.1136/bjsports-2020-102575][pmid: 32605932] 12. the intersection of covid-19 and mental health. lancet infect dis 2020;20(11):1217. [https://doi.org/10.1016/s1473-3099(20) 30797-0] [pmid: 33038942] https://www.acsm.org/blog-detail/acsm-blog/2020/03/30/exercise-immunity-covid-19-pandemic https://www.acsm.org/blog-detail/acsm-blog/2020/03/30/exercise-immunity-covid-19-pandemic https://www.acsm.org/blog-detail/acsm-blog/2020/03/30/exercise-immunity-covid-19-pandemic https://doi.org/10.1177%2f1403494807085373 https://dl.acm.org/doi/proceedings/10.1145/3154862 https://dl.acm.org/doi/proceedings/10.1145/3154862 https://dl.acm.org/doi/proceedings/10.1145/3154862 https://doi.org/10.3390/nu12061583 https://doi.org/10.3390/su12114356 http://dx.doi.org/10.1136/bjsports-2020-102575 original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license injury prevention knowledge, beliefs, and practices among women’s football teams in south africa u bakare,1 msc; b olivier, 1,2 phd; c brandt, 1,2 phd; l godlwana,1 phd 1 department of physiotherapy, school of therapeutic sciences, faculty of health sciences, university of the witwatersrand, johannesburg, south africa. 2 wits sport & health (wish) research group, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: u bakare (ummubakare@gmail.com) football is the world’s most popular sport, with an estimated 300 million registered players globally.[1] regardless of the level of professionalism, football-related injuries are common. also, irrespective of gender, the most common injuries reported in football are knee, hamstring, groin and ankle injuries.[2, 3]apart from the common injuries associated with men’s and women’s football, there are also other specific injuries, such as anterior cruciate ligament (acl) injuries, that are sustained mainly by women.[2] owing to the increased qangle and increased joint laxity arising from their particular hormone status and waist-hip ratio,.[2] women have been found to be at higher risk of presenting with acl injuries. the estimate of 30 million women players across the globe is an indication of the significance of their participation in football. as reported by the fédération internationale de football association (fifa), about 4.8 million women are registered by national federations worldwide. [4] the women’s football survey of 2014 shows that the confederation of african football (caf) comprises 1 255 400 members and these numbers have been projected to continue to rise.[4] in an annual european study of the professional women’s league in germany, 246 injuries were reported, thus accounting for an injury rate of 3.3 per 1 000 hours (games: 18.5 per 1 000 hours; practice: 1.4 per 1 000 hours).[5] injury prevention at any level in football is of utmost importance given the challenges of reduced performance, adverse financial impact, team success and the long-term health of the players.[6] structured generalised warm-up programmes have been shown to prevent common injuries in football [7] although injury prevention programmes (ipps) are highly effective in structured randomised control trials (rcts) and prospective controlled studies, this does not guarantee their effectiveness in the realworld context of implementation.[7] in addition to the knowledge of the various ipps, their permutations and strategies, a better understanding of the implementation context is important for success in this regard in the real world.[7] injury prevention in sports holistically entails using structured interventions and a multidisciplinary approach to improve the intrinsic and extrinsic risk components to optimise performance and protect the health of players.[8] some of these intrinsic factors include flexibility, endurance, strength, agility, coordination, and balance, while extrinsic factors include the kits of the players, the available equipment and training surfaces, weather conditions, and the rules of the game. prevention strategies are comprised of but are not limited to interventions that involve training and prehabilitation. both include neuromuscular exercises for warm-ups and cooldowns, flexibility, agility, strength, and conditioning. other considerations include hydration, nutrition, and psychotherapy.[8, 9] compared to other sports, football is a vigorous sporting activity, with a relatively high incidence of injury, so that preventative programmes to reduce the number of injuries, background: numerous factors account for injury prevention or lack thereof in any team setting. with the increasing burden of injuries in women’s football, and limited human resources accessible in sub-saharan africa, it is important to investigate the ways in which standardised injury prevention practices can be achieved. objectives: the study aimed to evaluate injury prevention knowledge, beliefs, and practices in women’s football teams in the university sport south africa (ussa) football league in gauteng province, south africa. methods: a cross-sectional self-administered survey was conducted among women’s football teams registered to participate in the ussa football league in south africa’s gauteng province. results: a total of 107 respondents participated in the study, which included both players (n=98; 92%) and their support staff (n=9; 9%). the median (interquartile range) age of the participants was 22 (20-25) years. in the population sampled, 36% of the participants perceived that they had adequate knowledge of injury prevention practices in football, while others felt they had limited knowledge of the basic injury prevention programmes (ipps). the results also indicated that the injury prevention practices of coaches (93%) and their beliefs in this regard (70%) are sufficient for achieving the basic injury prevention goals. most of the respondents (89%) indicated that a medical support system is important in attaining the goals of injury prevention. conclusion: members of women’s teams in the ussa football league have recognised limited knowledge about the basic ipps, while they do employ some of the basic injury prevention practices in football. these practices could be influenced by the beliefs of the coaches and the players, and most of them believe that ipps are important. it is essential as key stakeholders that coaches' and players' education and knowledge of injury prevention strategies should be considered as an integral part of the process to succeed. it should be strongly highlighted and implemented, thus augmenting the credibility, trust and compliance for ipps in the sport. keywords: fifa 11+, soccer, female, sport, implementation s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a9505 about:blank http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9505 https://orcid.org/0000-0002-8445-1348 https://orcid.org/0000-0002-4526-753x https://orcid.org/0000-0001-9287-8301 https://orcid.org/0000-0002-4112-0901 original research sajsm vol. 33 no. 1 2021 2 limit early retirement, and provide a healthy and safe environment for players, are highly recommended.[10] based on the current literature, the fifa 11+ comprehensive warmup programme is a leading ipp which has been proven in scientific studies to significantly mitigate the burden of injuries and reduce time-loss in football.[11] previous studies were carried out mainly in settings associated with superior human and infrastructural resources, and the results are therefore not comparable to those in sub-saharan africa generally.[12-14] the fifa 11+ programme was first implemented on a large scale in a women’s football population in norway.[14] thereafter, the programme was implemented and tested on mainly male football populations in countries such as the netherlands, [15] nigeria, [16]usa [13] and australia..[12] there is generally a dearth of knowledge on injury prevention, injury prevention practices and implementation studies on the african continent. in 2014, in their research conducted in canada, mckay et al. concluded that gaps in injury knowledge and beliefs differ for coaches and players.[17] a paradigm shift in the realm of injury prevention in football and other sports now manifests as a global phenomenon that has made a substantial positive public health impact in that it reduces the burden of injuries, thereby optimising performance and subsequently translates into team success. to understand the existing body of knowledge and practices of injury prevention, it is important to identify the core components if the relevant implementation strategies are to succeed. each environment and each demographic is unique, considering the existing parameters that could promote compliance in attaining the injury prevention goals, which require access to the current baseline knowledge and the practices that can be accessed.[18] to enhance the ultimate impact of team ball sport exercise-based ipps, the future reporting of exercise-based ipp trials must clearly address all aspects of programme delivery, as outlined by the reach effectiveness adoption implementation maintenance (reaim) framework.[18] apart from the implementation of a comprehensive ipp, some basic injury prevention principles, such as warm-ups, stretching, cool-downs and jogging, are also beneficial in reducing injuries in football. women’s football is currently in a developing phase, and there have recently been reports of local professional leagues gathering momentum in south africa. with limited resources and access to healthcare facilities proving to be expensive, injury prevention strategies will help to lighten some of the burdens associated with participation in football. the aim of our study was to evaluate the knowledge, beliefs and practices pertaining to injury prevention among members of women’s football teams in the ussa football league in gauteng province, south africa. methods study design and setting this study is a cross-sectional survey of injury prevention knowledge and practices among women’s football teams in the ussa football league in gauteng province, south africa. participants all women’s teams and their support staff, consisting mainly of head coaches, assistant coaches, team managers and occasional medical staff in the ussa football league in gauteng, were invited to participate. the ussa football league is a competitive football competition consisting of university teams playing in a league format. ten women’s football teams were eligible to participate in this study, consisting of an estimated population of 180 players and 20 coaches and support staff. all participants who gave their written informed consent were eligible to participate. ethical consideration the university of the witwatersrand human research ethics committee (medical) approved the study (m161146). permission was granted by the ussa football league and all the participating football team managers. all participants read, understood, and signed a written informed consent form. questionnaire the self-administered questionnaire was adapted from a study by mckay et al. [17] the questions included the domains of sociodemographic attributes, playing and training characteristics, injury prevention practices, other injury prevention aspects and associated beliefs. the questionnaire was structured to include a dichotomous ‘yes’ and ‘no’ two-point scale, while a fivetable 1. socio-demographic characteristics of the participants (n=107) characteristics n (%) gender female 102 (95) male 5 (5) designation assistant coach 4 (4) head coach 3 (3) player 98 (92) team manager 2 (2) team north west-vaal 15 (14) sefako makgatho university 9 (8) tswane university of technology 8 (8) university of johannesburg 22 (21) university of pretoria 24 (22) vaal university of technology 9 (8) wits university 20 (19) player position (n=98)* defender 41 (42) goalkeeper 11 (11) midfielder 21 (21) striker 25 (26) *player position is number of players, less number of support staff. original research 3 sajsm vol. 33 no. 1 2021 point likert scale was used to measure agreement across the extremes of ‘strongly agree‘ to ‘strongly disagree’. the questionnaire was validated for content and face validity with sports medicine experts and was piloted with an amateur male football team that did not form part of the study. procedure a total of 10 teams regularly participates in the ussa football league, and of the ten teams, seven teams consented to participate in the study. informed consent was sought from the individual players and support staff, and the questionnaire was administered at the respective practice venues for each of the teams. data were collected through site visits to training sessions between july 2017 and march 2018. appointments were scheduled with the respective team managements for the researcher to administer the questionnaires. statistical analysis data analysis was performed using the ibm spss 25.0® programme. the shapiro-wilk test was used to determine the normal distribution of the continuous data i.e. age and years of experience. descriptive statistics of the median and interquartile range (iqr) were used to summarise the continuous data, as these data were not normally distributed. the interquartile range was presented as the difference between the 75th and 25th percentiles.[19] percentages and frequencies were used to summarise the categorical variables. missing data were regarded as missing. results the estimated population size was initially envisaged to be 200 participants, but only 54% (n=107) eventually participated in the study. the median (iqr) age and years of experience of all the participants was found to be 22 (20-25) years and 36 (12-48) months, respectively. the median (iqr) ages of the players and support staff were 22 (20-24) years and 32 (25-39) years, respectively. the socio-demographic characteristics of the participants are outlined in table 1. of the 107 participants, 36% (n=38) reported they perceived that they had an adequate knowledge of injury prevention. it was also shown that 76% (n=81) of the participants were engaged in football ipp at the time of the research, with the following injury prevention practices being relevant: warmups (95%), stretching (90%), cool-downs (80%) and jogging (81%). most of the participants (67%) generally engage in injury prevention practices daily and 87% reported carrying out injury prevention practices during matches and team training sessions (70%). only 25% of the respondents indicated that they had heard about the fifa 11+ ipp, while the majority (83%) stated that they would be willing to adopt it if they were to gain access to detailed information on the programme (table 2). in table 3, most participants (87%) strongly agreed that ipps are important, and 66% believed that medical support is important in achieving injury prevention goals. most of the participants (65%) also strongly agreed that their coach’s table 2. injury prevention knowledge and practices (n=107) questions n (%) do you engage in any football injury prevention practices? (yes) 81 (76) type of injury prevent practices* warm-ups 77 (95) stretching 73 (90) cool-downs 65 (80) jogging 66 (81) did you receive any training in the injury prevention practices that you are currently engaged in? * (yes) 59 (72) how many times do you engage in the injury prevention practices that you use? * daily 54 (67) weekly 17 (21) monthly 10 (12) frequency per week∞ once 24 (30) twice 26 (32) thrice 11 (14) other 18 (22) when do you carry out ipps? * match days 7 (9) training 17 (21) both 57 (70) during which training session do you carry out ipp? * self-training 11 (14) team training 60 (74) both 10 (12) are your injury prevention choices based on your personal beliefs about preventing injury? † (yes) 35(33) do you think that the injury prevention practices that you engage in are based on scientific research? † (yes) 56 (52) do you think that you would be willing to adopt a different injury prevention strategy from that which you are already engaged in? † (yes) 64 (60) do you think that your knowledge about injury prevention in soccer is adequate? † (yes) 38 (36) do you think that you are effectively applying this knowledge as a football player/coach? † (yes) 65 (61 do you think that your current injury prevention strategy works? † (yes) 52 (49) have you heard about the fifa 11+ football ipp? † (yes) 26 (25) are you interested in adopting the fifa 11+ football ipp? † (yes) 89 (83) *; n=81, percentage based on participants that answered ‘yes’ to the preceding question “do you engage in any football injury prevention?”. ∞; n=79, missing data, less participants who did not complete the question in the self-administered questionnaire. †; n=107, percentage based on the total number of participants. original research sajsm vol. 33 no. 1 2021 4 prevention practices are sufficient for attaining injury prevention goals. a considerable number of the participants reported ‘don’t know’ in the following instances: african beliefs significantly affect injury prevention practices (41%), and the coach’s beliefs are important in achieving injury prevention goals (18%). it was also shown that the majority (66%) of the respondents indicated that a medical support system is important in achieving the injury prevention goals (table 3). discussion knowledge of injury prevention practices in our study, only 36% of the participants reported that they perceived themselves as having adequate knowledge of basic injury prevention practices in football. other studies on injury prevention have reported similar results.[17, 20] in the research conducted in canada by mckay et al.[17] they showed a dearth in the perception of knowledge and beliefs in young amateur female soccer players, emphasising effective prevention strategies and injury risk factors, but with significant differences in feedback from coaches and players. a study conducted in nigeria among a youth football league reported that most players fall within the poor and fair knowledge categories.[20] another study in south africa, which evaluated the coach’s knowledge, attitude, and perceptions regarding injury prevention among amateur footballers, showed that knowledge perception about injury prevention in coaches is limited.[21] this indicates that knowledge may still be a challenge irrespective of geographical location. however, in a study by geertsema et al.[22] conducted to evaluate knowledge, beliefs and strategies in a cohort of players at the fifa women’s world cup, concluded that elite female footballers reported awareness of the level of risk and the types of injuries in women’s football. the authors also suggested that players hold positive attitudes towards injury prevention. the good knowledge score demonstrated in the study by geertsema et al.[22] might be because the study was conducted amongst elite female footballers who have access to better economic resources and support staff. the perceptions of knowledge concerning football injury prevention reported in our study are in tandem with those recorded in some previous studies.[20, 23] in the south african context, this might be because the participants are primarily students and amateur players. in addition, there is limited infrastructural and financial support in the growing women’s football league in south africa.[24] a systematic review conducted by al attar et al.[11] concluded that adequate knowledge about injury prevention in football reduces the incidence of injury and improves performance. studies that have implemented exercise-based ipps in sports have recorded a significant reduction in injury incidence.[25] therefore, it is imperative that adopting and implementing a standard ipp needs to take into account and include the improvement of the knowledge base of the programme by educating the players and coaches about injury prevention practices and injury risk factors. thus, adequate education in injury prevention strategies directed at all role players, particularly the coaches, is paramount.[25] injury prevention practices employed by members of women’s football teams the common injury prevention practices reported by participants include warm-ups, cool-downs, jogging, and table 3. injury prevention beliefs (n=107) beliefs strongly agree agree don’t know disagree strongly disagree 1 injury prevention practices are important in football. 93(87) 9(8) 1(1) 2(2) 2(2) 2 a medical support system is important in achieving the goals of injury prevention. 71(66) 24(22) 7(7) 3(3) 2(2) 3 the coach’s injury prevention practices are sufficient for achieving injury prevention goals. 70(65) 29(27) 6(6) 2(2) 4 the player’s knowledge is important in achieving injury prevention goals. 67(63) 31(29) 5(5) 2(2) 2(2) 5 identifying injury risk factors and modifying them contributes to achieving injury prevention goals. 62(58) 33(31) 11(10) 1(1) 6 it is key to work as a team to achieve the goals of injury prevention.* 67(63) 36(34) 2(2) 1(1) 7 injury prevention is directly related to team success. 59(55) 35(33) 11(10) 1(1) 1(1) 8 compliance to an ipp is important in achieving its set goals. 59(55) 40(37) 6(6) 1(1) 1(1) 9 the coach’s beliefs are important in achieving injury prevention goals.* 37(35) 37(35) 19(18) 8(8) 5(5) 10 the fifa 11+ football ipp is important in achieving injury prevention goals.* 73(69) 31(29) 2(2) 11 an implementation guide is important in achieving injury prevention goals.* 56(53) 38(36) 11(11) 12 african beliefs significantly affect injury prevention practices.* 26(25) 20(19) 44(42) 9(9) 6(6) 13 injury prevention practices enhance performance optimisation.* 56(54) 31(30) 17(16) data displayed as n (%). * indicates missing data (q6, q7 and q 10: n=106); (q11 and q12: n=105); q13: n=104) – less participants who did not complete the question in the self-administered questionnaire. original research 5 sajsm vol. 33 no. 1 2021 stretching. these injury prevention practices have also been reported in the literature to reduce the incidence of footballrelated injuries.[2, 11] however, a more comprehensive warmup protocol that encompasses all these components has been developed and its efficacy has been proven in several studies.[11] warms-ups physically prepare athletes for the competition, and influence their mental state of mind, which is crucial to optimising performance. a well-designed warmup programme will achieve physiological responses in the cardiovascular, musculoskeletal, respiratory, nervous, and metabolic systems.[26] these responses include a raised tissue temperature, increased circulation to working muscles, and enhanced oxygen supply from the oxy-haemoglobin and myoglobin breakdown. cool-downs are the first step in the recovery process, the gradual tapering down of activities from an intense session of exercise, and the commencement of a ‘reverse phase’ of the warm-up process. a cool-down is effectively the tapering-off phase at the end of explosive physical activity and is typically at low intensity.[26] another key component is stretching, which may be static or dynamic. stretching aims to return muscles that have typically been shortened because of contractions during explosive sporting activity back to their resting length or their pre-activity state.[26] although it is important to note that these injury prevention practices are helpful in isolation, each component combined with the others will constitute a concerted effort towards achieving the injury prevention goals. very few of the participants in our study were aware of the fifa 11+, which is a comprehensive injury prevention programme, but the majority were keen to learn more about it and adopt it. beliefs about injury prevention from our results, coaches and players believe ipps work, and that they would be willing to adopt them. it has been shown that the coach plays the most important role in adopting and implementing injury prevention practices.[25] the majority of the participants identified that their coach’s beliefs are important in achieving injury prevention goals, and they believe that compliance is a key component of ipps. interestingly, in our study, the participants expressed that their coach’s ipp strategy is adequate even though only 36% reported that their particular knowledge about injury prevention in football is based on their own perceptions. this is not surprising, as often in sports, the relationship between the coach and the player follows a one-directional pattern where the coach is considered as the mentor, leader and guide in the career of the players.[25] in addition, the majority of the coaches are males, and the female-male dynamic element in sports usually influences the communication strategy and interpretation.[27] when a coach is keen on a programme, he/she will tend to influence the team’s knowledge and training regarding injury prevention, hence achieving the injury prevention goals. professional women’s football in south africa is in the developmental stage, with the amateur leagues showing considerable improvement in terms of personnel and infrastructure.[24] currently, because of limited personnel, the coach plays multiple roles in managing the team by providing medical support, leading the strength and conditioning programmes, and the injury prevention practices. this study also shows the lack of adequate medical personnel available on the team’s support staff, which might be largely due to the economic circumstances of the team. therefore, it is pertinent that for the successful implementation of an ipp strategy in a lowto middle-income setting in countries such as south africa, the coach will play a pivotal and integral role in the implementation plan, adoption, compliance, and overall implementation of such a programme. limitations this study was limited to women’s football teams in the ussa football league in gauteng province; therefore, the findings should not be generalised to other populations, sports, and demographics. the questionnaire used in this study was selfadministered and is based on the individual perceptions of participants and therefore might be subject to bias. recommendations the potential burden of injuries will continue to grow within the current environment and the increasing participatory numbers in women’s football in south africa. to mitigate this burden of injuries associated with football participation, it would be pertinent to incorporate evidence-based ipps to achieve the desired goals of injury prevention. there needs to be a paradigm shift to the effect that the adoption and implementation of holistic injury prevention practices would reduce the incidence of injury and improve the performance of the players and the overall achievements of their teams. as key stakeholders, coaches’ and players’ education and knowledge of injury prevention strategies should be considered an integral part of the process to succeed, strongly highlighted and implemented, thus augmenting the credibility, trust, and compliance for ipps in the sport. proper understanding might lead to a simple screening process that would be meaningful for ipps. it is also important to ensure that medical support should be an integral part of the process of achieving the injury prevention goals. therefore, as recommended by the re-aim framework for implementation, it is important to be purposeful and devise an implementation strategy for ipps. conclusion most members of women’s football teams perceived their level of knowledge as inadequate. although the respondents engage in various injury prevention practices, such as warm-ups, stretching, cool-downs and jogging, very few are aware of the fifa 11+ football ipp. most players and coaches believe that ipps are essential, which are crucial first steps towards developing and implementing injury prevention awareness programmes. conflict of interest and source of funding: the authors declare no conflict of interest. the study was funded by the university of the witwatersrand financial aid programme and the frc original research sajsm vol. 33 no. 1 2021 6 grant from the faculty of health sciences, university of the witwatersrand, johannesburg, south africa. acknowledgements: we would like to acknowledge the ussa football league and the women’s teams of all the participating universities in gauteng province, south africa. author contributions: all the authors were involved in the conceptualisation and the design of this study, the analysis, and interpretation of the data, the drafting of and/or the critical revision of the important intellectual content incorporated in the study, and the approval of the version to be published. the study constitutes part of candidate ub doctoral research, and bo, cb and lg were the supervisors on the project. references 1. dvorak j. keynote address. football medicine: the landscape. isokinetic medical group, xxiv international conference on sports rehabilitation and traumatology, 11-12 april 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[doi:10.1136/bjsports-2014-093543][pmid: 24928848] 18. o’brien j, finch cf. a systematic review of core implementation components in team ball sport injury prevention trials. inj prev 2014;20(5):357-362.[doi:10.1136/injuryprev-2013-041087][pmid: 24706721] 19. han j, kamber m, pei j. data mining concepts and techniques. 3rd ed. amsterdam: the morgan kaufmann publishers, 2012, chapter 2, getting to know your data: 39-82. 20. owoeye o, akinbo s, olawale o, et al. injury prevention in football: knowledge and behaviour of players and availability of medical care in a nigerian youth football league. s afr j sports med 2013;25(3):77-80. [doi:10.17159/2413-3108/2013/v25i3a361] 21. mtshali s, myezwa h, mbambo-kekana n, et al. coaches’ knowledge, attitude and perception towards injury prevention among amateur footballers. physiotherapy 2015;101 supplement 1:e1054. [doi:10.1016/j.physio.2015.03.1934] 22. geertsema c, geertsema l, farooq a, et al. injury prevention knowledge, beliefs and strategies in elite female footballers at the fifa women’s world cup, france, 2019. br j sports med 2021 epub ahead of print.[doi:10.1136/bjsports-2020-103131][pmid: 33397672] 23. barron mj, powell jw, ewing me, et al. first aid and injury prevention knowledge of youth basketball, football, and soccer coaches. int j coach sc 2009;3(5): 55-67 24. motshoene p. the rise of women’s football in south africa. available from: her football hub, 22 aug 2020. [https://herfootballhub.com/rise-of-womens-football-southafrica/] 25. o’brien j, hägglund m, bizzini m. implementing injury prevention: the rocky road from rct to real-world injury reduction. aspetar sports med j 2018;7(16):70-76. 26. hedrick a. exercise physiology: physiological responses to warm-up. strength cond j 1992;14(5):25-27. [doi:10.1519/07440049(1992)014<0025:prtwu>2.3.co;2] 27. murray p, lord r, lorimer r. the influence of gender on perceptions of coaches’ relationships with their athletes: a novel video-based methodology. the sport journal 2018; 22. https://resources.fifa.com/image/upload/fifa-womens-football-survey-2522649.pdf?cloudid=emtgxvp0ibnebltlvi3b https://resources.fifa.com/image/upload/fifa-womens-football-survey-2522649.pdf?cloudid=emtgxvp0ibnebltlvi3b https://resources.fifa.com/image/upload/fifa-womens-football-survey-2522649.pdf?cloudid=emtgxvp0ibnebltlvi3b file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1136/bjsports-2013-092215 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1136/bjsports-2013-092215 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1136/bjsm.2008.056069 doi:%2010.1177/28.suppl_5.s-3 doi:%2010.1177/28.suppl_5.s-3 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1136/bjsm.36.5.354 https://doi.org/10.1177/1747954117707482 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1177/0363546515602009 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1136/bmj.a2469 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1136/bjsports-2012-091277 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1136/bjsports-2012-091277 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1136/bjsports-2014-093543 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/10.1136/injuryprev-2013-041087 https://doi.org/10.17159/2413-3108/2013/v25i3a361 https://doi.org/10.1016/j.physio.2015.03.1934 doi:%2010.1136/bjsports-2020-103131 https://herfootballhub.com/rise-of-womens-football-south-africa/ https://herfootballhub.com/rise-of-womens-football-south-africa/ https://doi.org/10.1519/0744-0049%281992%29014%3c0025%3aprtwu%3e2.3.co%3b2 https://doi.org/10.1519/0744-0049%281992%29014%3c0025%3aprtwu%3e2.3.co%3b2 editorial nineteen ninety five will be remembered as the year in which south african sport finally emerged from isolation to regain international respect. the victory o f the springbok team in the rugby world cup final on saturday june 24th restored an uncertain national sporting pride and was, just perhaps, the greatest single achievement in the history o f south african sport. correctly, much has been made o f the importance o f that victory for the unifi­ cation o f our fledging nation. but for sport and especially the sports sciences and sports medicine, the long-term effects o f that victory hold equivalent potential. indeed that single victory may yet revolutionize south african sport and help to propel it, at first grudgingly and reluc­ tantly, into the 21st century. too little has been made o f the significant contribution made by members o f our association to that historic vic­ tory. in a soon-to-be released book analysing the basis for the south african victory, former springbok rugby captain and 1995 world cup manager, monie du plessis, pays spe­ cial tribute to the medical team that supported the springboks team physician dr frans verster, team phys­ iotherapist evan speechley and applied kinesiologist ron holder. in the developing tradition o f south african sports medicine teams, this group “ gave unselfishly o f their time and expertise, sparing nothing in the support o f their team” . to their contribution and example must be added those o f the large number o f physiotherapists, bio kineticians, psychologists, doctors, sports scientists and other colleagues who week after week during an increas­ ingly long winter season, have ministered to the medical, mental, spiritual and psychological well-being and have maintained and improved the physical condition o f all our provincial rugby stars, who are the fountainhead on which the success o f our national rugby team was based. by helping to make that victory a reality', the abiding con­ tribution o f those colleagues will be to hasten the accep­ tance o f sports medicine and the sports sciences as a cru­ cial component o f international sporting success by both the general public and those less innovative sports admin­ istrators. indeed since the rugby world cup victory, the united cricket board o f south africa has increased the number o f sports medicine professionals, contracted on either a partor full-time basis from 2 (physiotherapist and exercise specialist) to 5 (dietician, podiatrist and psy­ chologist). a visiting sports orthopaedic surgeon who works with a number o f professional teams in the southern united states, remarked recently that sports medicine in this country stands on the brink o f a revolution s i m i l a r to that which launched sports medicine in the united states 25 years ago. and the common ingredient is a compelling national interest in sport and the growth o f professional sport. what south africa has, in addition, is the desire o f at least three sports (rugby, cricket and to a lesser extent, soccer) to be the leading south african sport and com pet­ itive with the best in the world. sue]) desire will engender a healthy rivalry between those sports as each pushes the other to be more creative and innovative in the quest to capture the imagination o f the south african public. such rivalry promises much to those professions and profes• sionals who can assist in the achievement o f the ultimate goals o f those sports. and few professions have more to offer than sports medicine and the sports sciences. so we stand at the start o f what will prove to be the most exciting period ever in south african sport. we must grab the opportunities that present themselves and so insure the future o f both sport and our profession in the new nation. and, just perhaps, the very7 future o f the nation itself. to make the most o f those opportunities we must continue to increase our professionalism in both our sci­ entific research and in the service that we provide to our athletes. surprisingly, this journal will continue to be one crucial measure o f how far we are progressing. it will tell us whether we are achieving world class standards in both those areas. it will also measure the extent to which we have overcome the greatest threats to our future success which are to allay historical divisions and suspicions and to join all those involved in sports medicine and the sports sciences into one unified body with a common goal o f ser­ vice (above self) in the interests o f south african sport and all her athletes. when we can finally harness the abilities o f all our professionals in sports medicine and the sports sciences to that common goal, only then wall we be able to call ourselves and our .journal, world-class. this issue o f the journal covers two areas o f importance to our fixture capacity to serve south african sport. dr john hawley contributes 2 articles on applied physiol­ ogy'. in “ powder systems: implications for high-intensity swim training” , he reviews the contribution o f the differ­ ent metabolic systems to the energy used during exercise o f different durations and dispels som e o f the myths on which current swimming training regimes are based. this information is o f value in the education both o f ourselves but also o f our swim coaches, some o f whom might per­ haps question whether their current training programmes provide the optimal physiological stimuli necessary' to develop superior swimming performance. for example, he makes the point that “ it is difficult to understand how training for such prolonged periods at speeds which are „ markedly slower than planned race pace, prepares the swimmer for supra-maximal competitive efforts” . his second article provides state-of-the-art training guide­ lines for endurance performance. he makes the valuable point that “ ... during the past century, exercise physiolo­ gists can claim to have had only' a very limited impact on the training practices o f successful athletes w'ith the empirical field-based observations precipitating the majority o f breakthroughs in the training patterns o f top sports persons” . south african scientists should respond to this challenge by making their own contributions to this knowledge. both articles show how' a knowledge o f exercise physiolo­ gy aids in the development o f correct training methods. i f we are to improve the performances o f our athletes in international competition, w'e also need more informa( continued on p a g e 12) sports medicine september 1995 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) u s t w h a t a t h l e t e s w o u l d e x p e c t f r o m a c o m p a n y c o m m i t t e d t o s p o r t . smith1* nephew f o r f u r t h e r leadership in worldwide healthcare i n f o r m a t i o n c o n t a c t t r o y b i n g h a m o n ( 0 3 1 ) 7 0 1 5 2 4 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m i ; s o i ti i .u r k a x j o i k y w. o r sports medicine volume 2 number 4 november 1995 editors p roft d noakes d r mp schwellnus editorial board dr m e moolla dr p de jager d r j s k o w n o d r p schwartz p rof r stretch d r c de ridder p r o f b c andrews dr e w derman mr r h farman dr r h mars d r c a noble international advisory b oard lyle j micheli a ssociate clinical professor o f o rthopaedic surgery boston, usa chester r k yle r esearch director, sports equipment research associates california, usa p ro f h c wildor hollmann president des deutschen sportarztebundes koln, west germany howard j green professor, departm ent o f kinesiology’ ontario, canada george a brooks professor, department o f physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke a ssociate professor, biolog)' department, university o f colorado colorado, usa graham n smith physiologist glasgow, scotland contents editorial td noakes 1 power systems: implications for high-intensity swim training ja hawley 4 state-of-the-art training guidelines for endurance performance ja hawley 7 instructions for authors 13 the metabolic demand of portage in kayak marathons m mars 15 die invloed van oefening op depressie: ’n meta-analise e pretorius jc jansen van rijssen jm van zyl 20 product news 24 the editor the south african journal of sports medicine po b ox 115, newlands 7725 production andrew thomas publishing glenbarr publishers cc private bag x i 4 parklaiids 2196 tel: (oil) 442-9759 fax: (oil) 880-7898 advertising marika de waal/andrew thomas reproduction output reproduction printing hortors cover sponsored by ciba-geigy the views expressed in individual articles are the personal views o f the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent o f the publishers. i sports medicine november 1995reprod uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) power systems: implications for high-intensity swim training ja hawley, phd, facsm introduction many coaches steadfastly believe that im provem ents in perform ance are directly related to th e volum e o f work p erform ed during training, and that a swim mer can only reach h e r /h is full potential b y undertaking extrem ely lon g and arduous training sessions. c om petitive sw im m ers, for exam ple, often train between two and four hours each day swim ming up to 20,000 m etres, with an energy expenditure exceeding 4 ,50 0 kcal/day. a s the majority o f com petitive swim ­ ming events last less than five minutes, it is difficult to understand how training for such prolonged p eriods at speeds which are m arkedly slower than planned race pace prepares th e swim m er for supra maximal com pet­ itive efforts (costill et al 1991). a swim mer’s speed and ability to resist fatigue during training and com petition depend on th e m uscles ability to produce m echanical w ork (force) from the break­ down o f stored chem ical energy (mainly carbohydrate and fat). this article d escribes the different m etabolic pow er systems that provide the energy for muscular contraction, examines th e contribution o f these systems to th e energy requirem ents o f maximal exercise, and details the b e st type o f workouts to train those systems. power systems when describing the physiological entities that pro­ duce the energy required to sustain all cellular p rocess­ es, including muscular contraction, m ost texts o f exer­ cise physiology, and alm ost all coaching manuals, use th e term “ energy system s” . however, as th e primary function o f such systems is to produce powder for exer­ cise, such term inology seem s inappropriate: it would seem conceptually m ore correct to call them pow7er sys­ tem s (hawley & h opkins, 1995). t he distinction betw een energy and powder systems is not merely semantic: th e output o f a physiological sys­ tem should b e quantified as the pow er that can b e p ro­ duced, and not m erely the amount o f energy potential­ ly available for muscular work. o bese individuals, for example, have vast reserv es o f energy stored in the form o f fat, but are not renowned for their ability to sus­ tain high power outputs! the body has four distinct power systems it can use to supply energy for exercise: two anaerobic (oxygen-inde­ pendent), and two aerobic. the nam es o f the power sys­ tem s represent descriptive summaries o f the com plex address for correspondence: dr ja hawley mrc/uct bioenergetics o f exercise research unit sports science institute o f s/1 box 115 newlands 7725 tel: (021) 686-7330 fax: (0 2 1 ) 686-7530 email: jhawley @ sports. uct. ac.za biochem ical pathways each uses to produce e n e r g y for muscular contraction. t hese systems are considered distinct by exercise scientists because (1) they have sub­ stantial!}7 different biochem ical pathways, (2) their rela­ tive contributions to d ie e n e r g y required for exercise depends on the intensity (speed) and duration o f an event, and (3) these contributions can b e m odified by appropriate training and dietary7 interventions. it should b e noted that for m ost olympic swimming events, tw7o, or at the very m ost three power systems are utilised. the atp-cp (phosphagen) system t h e phosphagen system uses adenosine triphosphate (atp) and creatine phosphate (cp) stored within the m uscle to provide energy for maximal bouts o f strength and speed that last for up to six secon d s (gaitanos, et al 1993). atp and cp are stored at the contractile site o f the m uscle, malting this anaerobic power system the m ost readily available for use during high-intensity ex­ ercise. t h e amount o f atp and cp stored within skele­ tal m uscle is, how7ever, quite low7 and the phosphagen system can only power bursts o f maximal exercise for very short periods. indeed, after only a few7 seconds o f exhaustive work, the power p roduced by the atp-cp system decays, so that after six seconds it provides only h a lf o f th e total energy requirements o f exercise (figure 1). t h e atp-cp pow7er system would b e used for the start and the initial seconds o f a 50 m sprint. the anaerobic (oxygen-independent) glycolytic system this system derives its name from the biochem ical path­ way that produces energy from the breakdown o f carbo­ hydrates without the use o f oxygen. t h is pow7er system is rapidly activated at the onset o f intense work, so that even during a six second maximal sprint, th e contribu­ tion to the total energy requirem ents o f exercise from anaerobic glycolysis reaches alm ost 50% (figure 1). in a sprint event lasting approximately 30 seconds, the con ­ tribution from anaerobic glycolysis to the total energy requirements o f exercise increases to 60% (m edbo and tabata 1989) (figure 1). a s would b e expected, the longer the exercise duration (or the slower th e swim speed ), the sm aller is the contribution to m uscle m eta­ bolism from th e anaerobic glycolytic system. thus, after a maximal effort lasting one minute, anaerobic energy release has decreased to 50% o f overall metabolism , and after two minutes o f high-intensity work, to around 35% (m edbo and tabata 1989) (figure 1). associated with the anaerobic release o f energy from carbohydrate is the production o f lactic acid by the working muscles. therefore, wrorkouts that develop the sw im m er’s ability to produce and tolerate high concentrations o f lactate are essential for th e successful sprinter. the aerobic glycolytic and aerobic lipolytic power systems t h e two aerobic pow er systems are nam ed for th e fact tli at they generate energy for m uscle contraction from the breakdown o f carbohydrate and fats in th e presence 4 sports medicine november 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) figure 1. the contributions o f the different exercise. power systems to the total energy requirements o f maximal event m ajor pow er duration system s utilised < 6 sec phosphagen < 30 sec phosphagen anaerobic glycolytic main fuel substrates atp-cp atp-cp muscle glycogen <15 m in a erobic glycolytic >15 m in a erobic glycolytic a erobic lipolytic m uscle glycogen blood glucose m uscle glycogen blood glucose intra & extra-muscular fat u l s ? ex,erc'se ls,ins longer than two m in­ utes and up to three hours is pow ered predom inantly by the aerobic glycolytic system. for longer, less intense exercise, and all ultra-endurance swim ming events the n s s f o f t h via aerobic upolytte system provides m ost of th e energy for m uscle m etabolism. note that fat ca”n° i oxidised hi the presence o f oxygen i l ie duration o f maximal exercise for which equal con ­ tributions to energy m etabolism are m ade by the aerobic glycolytic and aerobic lipolytic power systems is probably (ihnviey & h <>r>k " ^ 1995). during such prolonged endurance events, the use o f fat relative to cars increases as the intensity ol exercise decreases cbroofe and mercier, 1994). although botli carbohydrates and fats are likely to b e used as fuels by th e m uscle dur m g prolonged endurance training, com petitive swim stored ' n !)0were< alm° f d elusively by carbohydrate, stored m th e m uscle as glycogen (costill et al, 1988). implications f o r t r a in i n g c() tinhi!h'rlins a year' r.ound '■raini" g programme for d ie r ? w,nlnlei; l he specibc physiological demands anrvr s six'cl:dit>’ event(s) should be identified and a -e'th ' ? in: ng t<:cl,ni(jues em ployed that will en p ^-fo™ 5 are critical determinants o f illlvs i f “ kc| ^ s h o u l d always b e rem em bered that the u he s s n :l; a,ptati0ns ! ° " 'aining closely related a" d m od e o f gaining perform ed m g epeated days o f exercise. since there is little training objective and b est type o f workouts development o f explosive pow er sprint starts strength training (3 sets o f <4repetitions @ 95% o f 1rm) maximal sprints « 2 5 m ) with com plete recovery lactate tolerance hirt o ” airs peuu,,ns (<3° s£c) wiul lon« (3-5 m in) rest strength training (3 sets o f <8 repetitions @ 85% o f 1rm) d evelopm ent o f aerobic p ow er repetitions (1-5 min) with snort « 6 0 sec) rest intervals d evelopm ent o f aerobic endurance long repetitions (>5 min) with short « 6 0 sec) rest aeixrtyc ' continuous shim m ing at b e st steady-state cross-tram m g effect irom one pow er systems to anoth1 ° ne type o f exercise to another, workouts s lould b e structured to develop those power systems required for the swim mers speciality events (table 1). utilised"?! v u 111116 c0urse ° f , he p °wer systems utilised d im n g high-m tensily swim ming events cou­ p led with the need for specificity in lining should assist coaches in assessing w hether their current train­ ing regunens provide the optimal physiological stimuli necessary for superior swimming performance. references 1. brooks g a m mercier. the balance o f carbohydrate and lipid utilization during exercise: the cross-over’ concept j a v n l physiol. 7 6 :2 8 5 3 -2 2 6 1 , 1994. ‘ pp '■ d z s l n i t mg/ ch n, j p kirwan et al ejfkcts ° f repeated days oj intensified trainmg on muscle glycogen and swim, r i‘t t r nt cemecl sci sp°hs e x ™ so; “ 3. costill dl, thomas r. robergs r a et al. adaptations to m t /t t t gcj ° williams’ l h -boobis et al. human muscle ° " z t z 'n l w ° u ° pkit a e r ° btc ^ c° 1̂ ™ d aerobic lipolytic power system : a new paradigm with implications 2 4 0 ^ 2 5 a w 9 s and lluraendurance evelu*sports med 19: 6. m e d b o j i , tabata i. relative importance o f aerobic and anaerobic energy release during short-lasting exhaustinn bicycle exercise. j a pp l physiol 67 : 1881-1886, 1989. □ 4. sports medicine november 1995 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) accusporl is the first truly p orta ble m eter fo r m easuring lactote levels on the spot ■ affordable convenience at its best! accusport weighs o mere 12 0 g , it's a cinch to use, and the vital inform ation displayed could result in a pb. by measuring heart rate and lactate levels during exercise you can monitor degrees of exertion, optimise health benefits, maximise endurance and avoid over exertion. . trainers and sports group leaders know that customized training improves individual performance. . high-performance athletes and health-conscious sports people need to have personol control over their training. ■ physicians, physiotherapists and biokineticists in rehabilitation can provide greater safety in sport. 0 heart rale m time of day with d aily alarm 0 calendar • stopwatch with 3 0 lap time memoi y 0 target lap time 0 time spent & average hr recordings, within, above & below target zone • heort rote memory with 256 memory recordings 0 event markers 0 kcalaries burnt 0 water resistant • bike adapter included to these products, a wide range of heart rate monitors is available 0 heart rate • 12 or 24 haur time o f day • stopwatch • heart rate recording with selectable sampling intervals • -recall recorded heart rate • high & law heart rate lim it alarms • target zone indication • water resistant adapter included heartsafe excludes: time of day c a r d i 0 5 p * r t / i c c u s r t r r h e a r t r a t e m o n i t o r s o r m ore info rm atio n or the sto ckis n e a r e s t y o u , c a l l b i o m a r o l l f r e e : 0 8 0 0 2 2 4 6 8 on the s p a t / r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) state of the art training guidelines for endurance performance ja hawley, phd, facsm introduction and background the purpose o f this article is (1) to identify the physio­ logical factors associated with successful endurance perform ance and (2) provide training guidelines and specific workouts for athletes com peting in strenuous events such as cycling (40 kin time-trial and over), d is­ tance running (5 1cm and longer), the standard-distanee triatldon, and distance-swimming races. wherever p o s ­ sible scientific studies have been cited to support the physiological rationale underlying specific training principles. in addition the practical experience o f the author as a competitive athlete, coach and exercise physiologist involved in the testing, monitoring and prescription o f training to elite atjdctes in several con­ tinents during the past decade has been drawn on. it shoidd be noted at the outset that despite their best efforts, it has proved extremely difficult for sports scientists to manipulate the training regimens o f elite endurance athletes for the purpose o f scient ific inquiry. thus, during the past century, exercise physiologists can claim to have had only a very limited impact on the training practices o f sueecsslid athletes, with the em pi­ rical field-based observations o f coa ch es precipitating die majority ofbreakthroughs in the training patterns o f top sportspcisons (wells and pate 1988). nevertheless, many scientific investigations have consistently identi­ fied the physiological variables that are positively relat­ ed to successful endurance performance, 'fh ese variables are defined and briefly discussed, f l i c extent to which these and other factors are “ trainable” as opposed to genetically determ ined is a topic o f considerable debate (bouchard ct al. 1992). the reader is referred to the excellent reviews o f h olloszy et al. (1977) and saltin (1969) for more detaded discussions o f the physiologi­ cal adaptations to chronic endurance training. physiological factors relafed to successful endurance performance 1. maximal oxygen uptake maximal oxygen uptake (vo^. j is the greatest rate at which oxygen can be consiuned by an athlete during exer­ cise and, under steady-state conditions, is a reflection o f an individuals maximum rate o f aerobic energy utilisation (ast-iund and rodahl 1977; costill 1986; rowell 1986; sal­ tin and astrand 1967; wihnore 1984). studies performed over (illy years ago established dial oxygen uptake (vos) increased with running (h erbst 1928; ldjestrand and stenstroni 1920b) and swim ming speed (ldjestrand and stenstroni 1920a) and that the fastest athletes had die liighcst oxygen uptakes (herbst 1928; robinson et al. 1937). ( h e r the next fifty years credibdity was given to the b e lie f that vo*,,,,̂ was a good predictor o f athletic po­ tential in endurance sports (costill and winrow 1970a; costdl et al. 1973; davies and thom pson 1979; leary and wyndham 1965; wyndham e ta l. 1969). judging by the frequency with which the topic is discussed amongst athletes and coaches, it woidd still appear that the vast majority o f runners, cyclists and triathlctes implicitly believe that the v q .„» is d ie single best predictor o f atldctic potential in all endurance events (noakes 1988). although voi>m„» is a satisfactory' predictor o f endu­ rance performance in a heterogeneous group o f athletes (costdl et al. 1973; farred et al. 1979), individuals with similar vo-„„lx values can differ markedly in perfor­ mance velocity (costdl and winrow 1970b; coyle et al. 1988; daniels 1985; londeree 1986; noakes 1988). tabll 1; maximttm oxygen uptake values for som e elite endurance runners athlete vo,.., best perform ance reference (m l/k g /m in ) said aouita 83.0 12:58,39 (5 000 m) zur m egede and hymans (1991) .tolui walker 82.0 3 :49.08 (1 m ile) agnew (1976) steve scott 80.1 3:47.69 (1 m de) conlev et al (1984) sebastian coc 77.0 3:47.33 (1 mile) zur m egede and hvinans (1991) greta waitz 73.5 2h:24 .54 (marathon) peronnet and thibaidt (1989) peter snell 72.3 3:54.10 (1 m de) carter et al (1967) fraidt shorter 71.3 2h:10.30 (marathon) pollock (1977) willie mtolo 70.3 2h:08 .15 (marathon) noakes et al (1990) derek clayton 69.7 2h:08 .34 (marathon) costill et al (1971) address for correspondence: dr ja hawley mrc/uct bioenergetics o f exercise research unit sports science institute o f b ox 115 newlancls 7725 tel: (0 2 1 ) 686-7330 fax: (0 2 1 ) 686-7530 email: jh aw ley @ sports. uct. ac.za w hile vo,,.,,* in elite male m iddle and long-distance nuniers typically range from 75 to 85 m l/k g /m in , widi extreme values equal to or exceeding 90 n d /k g /m in (bergli 1978; conley et al. 1984; costill 1986; daniels 1974; martin ct al. 1986; pollock 1977; saltin and astrand 1967), such high values are probably not as critical for athletes participating in prolonged endu­ rance events which last 60 lnin or longer (table 1). 2. fractional utilisation o f oxygen uptake fractional utilisation refers to the percentage o f an ath­ letes vo_>„„,, that can be utilised at a specified speed or sports medicine november 1995 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) workrate (i.e. race pace). top marathon runners (i.e. sub 2 hr 20 min) can sustain ~86% o f voa,,,,,* lor the duration o f a race (costill 1972), whereas slower run­ ners (i.e. 2 hr 45 min up to 3 hr) can sustain only 75 76% o f their voa,„u* for th e sam e distance (farrell et al. 1979; wells et al. 1981). in cycling, despite similar vo-, , values (i.e. 69 m l/m in /k g ), elite national class riders are able to sustain 90% o fv o a„ for th e duration o f a 40 km time-trial com pared to 86% for good provin­ cial (state) riders (coyle et al. 1991). t h is greater frac­ tional utilisation of' vo-,,,,, perm its the elite cyclists to rid e considerably faster over 40 km com pared to the good riders (53 :54 min versus 60:00 min, respectively). although the physiological basis for th is endurance capability is not clearly understood (peronnet and thi bault 1989), it w ould appear that the fraction o f v q w that an athlete can sustain for prolonged p eriods is re­ lated to the accumulation o f lactic acid in th e active m uscles (costill et al. 1973; farrell et al. 1979; lafon taine et al. 1981; sjodin and jacobs 1981). in endu­ rance-trained athletes, for example, there is litd e or no increase in b lood (and presum able m uscle) lactate con ­ centration until an exercise intensity that elicits 70-85% o f v q w (costill 1986; costill 1970; farrell et al. 1979). 3. p e a k s u s ta in e d p o w e r o u tp u t recently, both sports physiologists (hawley and noakes 1992; hawley et al. 1992; morgan et al. 1989; noakes et al. 1990; scrim geour et al. 1986) and coa ch es (helle m ens 1993) have recognised th e im portance o f peak sustained power output as a predictor o f endurance p er­ formance. in runners, fo r example, th e peak treadm ill velocity d ia t an athlete can achieve during a maximal test lias been found to b e as good a predictor o f endurance perform ance as any physiological variable currently measured (morgan et al. 1989; noakes e t al. 1990). it has b een p roposed that th e factors which determ ine peak sustained m uscle pow er production in short duration, high-intensity events like running the 800-1,500 m m ight also determ ine perform ance in m ore prolonged endurance events, lik e th e marathon (noakes 1991). t his would explain th e field-based observations o f coaches like arthur lydiard (lydiard and gilm our 1978) and gordon pirie (pirie 1961), w ho claim that th ose distance runners who are th e fastest over th e shortest distances will also b e th e fastest over longer distances (noakes 1991). in cycling, th e peak sustained pow er output mea­ sured during an incremental cycle test to exhaustion has been shown to b e a valid predictor of perform ance during a 20 km time-trial (hawley and noakes 1992). in this regard, coyle et al. (1991) have observed that elite cyclists (m ean tim e o f 53:54 m in tor 40 km ) can sustain average pow er outputs o f 346 watts (w) for one hr, with d ie b est cyclists (51 m in for 40 km ) able to sus­ tain a power output o f 376 w/hr. 4 . f a tig u e r e s is ta n c e fatigue resistance is th e ability o f an athlete to resist fatigue (i.e. sustain a high power outp ut/speed ) during prolonged exercise, and is related to the contractile properties o f skeletal m uscle. a major adaptation to chronic endurance training is that th e skeletal m uscles involved in th e activity are m ore fatigue resistant than prior to training (fitts 1977). ind eed, a recent study from this laboratory has shown that th e superior p er­ formances o f elite black runners in events from 3,000 m up to the marathon are, in part, due to their superior resistan ce to fatigue com pared to w h ite runners (coetzer et al. 1993). it may well b e that an important com ponent o f training (and tapering) is to directly alter skeletal m uscle contractility (i.e. m uscle power) as orig­ inally proposed by noakes (1988). 5. t h e a n a e ro b ic "l a c t a t e ” th resh o ld t h e speed o f m ovem ent at w hich a specific b lood lac tate concentration (usually 4 m m ol/l ) is observed. lactate threshold m erely reflects the highest exercise intensity that an athlete can sustain for an extended period without amounts o f lactate accumulating that are limiting for perform ance (wells and pate 1988). a lthough there exists m uch debate as to the term inol­ ogy describing th e kinetics o f lactate accumulation dur­ ing steady-state exercise (brooks 1985; jacobs 1986), there is, regardless o f how it is m easured and defined, a close relationship betw een lactate threshold and en­ durance perform ance (coyle et al. 1988, 1991: sjodin and svedenhag 1985). in running, for example, endu­ rance training increases the speed at the lactate tum point and this change correlates closely with actual im ­ provem ents in running perform ance (tanaka et al. 1984). it is, however, unlikely7 that there is any relation­ ship between the lactate threshold and a heart-rate d e ­ flection point (kuipers et al. 1988; r ibeiro et ^ 1985), as was originally p roposed b y conconni et al. (1982). 6. e c o n o m y o f m o tio n economy o f m otion is th e cost (i.e. oxygen uptake) re­ quired to produce a specific workrate or speed o f move­ ment. t he best endurance athletes are usually th e m ost efficient (conley and krahenbuhl 1980; daniels 1974; noakes 1988). better econom y (i.e. a lower oxygen cost) is advantageous during endurance exercise as it is asso­ ciated with a slower rate o f energy utilisation (i.e. m us­ cle glycogen). i f fatigue during prolonged endurance events is associated with th e depletion of b od y fuel stores, then the more efficient athlete will b e able to cover a greater distance on the sam e amount o f fuel (noakes 1991). several studies suggest that, for running at least, a major benefit o f the high (i.e. greater than 120 km ) weekly training distances that elite athletes maintain is a p rogressive increase in running efficien cy (scrim geour et al. 1986; sjodin and svendenhag 198o). with prolonged endurance training (i.e. 3-4 years expe­ rience) runners also tend to decrease the length o f their stride at a given velocity, w ith a concom itant increase in stride frequency (nelson and gregor 1986). elite run­ ners also appear to ch ose an optimal stride length at w hich they are m ost efficient (i.e. at which th e oxygen cost is th e least) and when forced to take either longer or shorter strides for the sam e running velocity they require an increased oxygen uptake, thus becom ing less efficient (cavanagli and williams 1982). analogous to the long-slow distance training o f run­ ners top cyclists cover many' m iles, albeit at relatively7 fast speeds, at a high cadence (90-120 revolutions/ min) in a low gear ratio in order to develop a sm ooth efficient leg stroke at speed (i.e. spinning). o f interest here are the results o f a recent study by coyle et al. (1992) that showed that among a group o f well-trained cyclists, cycling econom y at submaxiinal workrates d if­ fered by as m uch as 15%. such differences in efficiency were not due to differences in cycling technique but, instead, related to the number o f slow-twitch (type i) m uscle fibres in the quadriceps m uscles o f the cyclists; th ose subjects with a high percentage o f type i m uscle fibres were m ore efficient (i.e. required less oxygen) to work at either 50% o f 70% ofvo»„,„ than subjects with a low7 percentage o f slow-lwitch fibres (coyle et al. 1992). 8 sports medicine november 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) in swimming, tlie distance covered with each stroke has been shown to be an excellent predictor o f p erfor­ m ance for both sprint and distance events (costill et al. 1985; hawley et al. 1992). for a given speed, a swim ­ m er who has the greatest stroke-distance is assum ed to have the m ost efficient technique (costill et al. 1985). such a technique is assumed to b e a direct con se­ quence o f the enormous distances covered by m ost swim mers during training. 7. fuel utilisation at high workrates (sp eed s) there is a greater reliance on carbohydrate than lipid substrate (b ock et al. 1928). highly-trained endurance athletes can m ake greater use o f fat as a fuel for energy provision during high-in tensity submaximal exercise than less trained individu­ als, thereby conserving m uscle and liver glycogen stores. however, the w hole concept o f training longer and fur­ ther to increase the muscles ability to utilise fat remains contentious. for example, i f an athlete trains m ore than 60 m in /da y there is little additional enhancem ent o f the m uscles ability to utilise fat as a fuel in preference to carbohydrate (coyle ef, personal com munication). in summary, the principal physiological requirements o f an endurance a th lete wishing to com pete at a high level during prolonged exercise are: (1) a high but not phenomena] y( ) (2) the ability7 to utilise a high p er­ centage o f voa„„ for sustained periods, (3) the ability to sustain high pow er outputs and resist muscular fatigue during prolonged exercise, (4) a high pow er output (or speed ) at the lactate threshold, (5) an efficient te ch ­ nique, and (6) the ability to utilise fat as a fuel during sustained exercise at high workrates. training techni­ ques to prom ote these physiological adaptations will now b e discussed . t r a in i n g t e c h n iq u e s f o r s u c c e s s f u l endurance performance since world war ii the training practices o f elite endu­ rance athletes have passed through several identifiable and distinct phases. t h ese stages can usually b e asso­ ciated with influential coaches o f the tim e (i.e. franz stampfl, percy cerruty and arthur lydiard in running; forbes carlile and jam es councilman in swimming; cyrile guimard and e ddie borysewicz in cycling), each o f whom has been credited with the development o f a num­ ber o f leading athletes. a s a result, there currently exists a multitude o f diverse training techniques for d ie perfor­ mance o f prolonged exercise. elaborate training systems based on multiply macro and m icro cycles with specific attention to the periodisation o f training have been p ro ­ posed. however, such program mes are often theoreti­ cally based, lack scientific validity, and are o f little prac­ tical value for the majority o f coaches and athletes who m ust often train all year round to com pete successfully on an international level (h opkins 1993; horwill 1992). a com m on trend in many endurance sports has been or coach es and athletes to adopt and im plem ent the prevailing training regimens o f current w7orld-class per oriners in their discipline. w hile such a practice has obvious drawbacks and typically results in th e downfall ot many a prom ising athlete, this m ethod may, occa ­ sionally, contribute to th e unprecedented success o f an individual. in this regard, it is generally assum ed by many coaches and athletes that improvements in p er­ formance are directly related to the amount o f work perform ed during training, and that an athlete can only reach his or her full potential by undertaking extrem e jy long and intense training (costill et al. 1991). a l­ though the volume o f exercise is among th e variables known to determ ine the degree o f adaptation to train­ ing (davies and knibbs 1971; faria 1970; fox et al 1973, 1975; shephard 1968), there is now evidence, at least for swim mers, that such extensive training may not necessarily enhance performance (costill et al. 1991). intuitively th e perfect training program m e for endu­ rance perform ance should include elem ents o f all the training techniques currently practiced by todays suc­ cessful performers. how7ever, m ost o f the key facets that constitute the generic core o f a year-round training p ro­ gramm e for the endurance athlete can b e divided into ju st three main phases: (1) b ase or foundation training, ) transition training, and (3) speed or power training, incorporating a taper phase before a major com petitive peak. during each phase o f training primary emphasis is given to the development o f one (or more) specific physi­ ological objectives (i.e. the developm ent o f fatigue resis­ tance, or th e im provem ent o f econom y o f motion etc.). 1. base/foundation training performed during th e winter or th e non-competitive period o f an athletes m acrocycle, the primary em phasis of this phase o f training is the establishm ent o f a sound aerobic foundation on which to base subsequent (m ore intense) training (lem ond and g ordis 1990; lydiard and g ilm ore 1978, 1983; wells and pate 1988). t h e physiological benefits ascribed to b a s e / foundation training include enhancem ent o f myocardial function (clausen 1977) and oxygen transport (ekblom 1969), an increase in b lood volume (convertino et al. 1980),' enhancem ent o f m itochondrial and oxidative capacity o f skeletal m uscles (fink et al. 1977; kiessling et al. 1971; saltin 1969) and improved fat m obilisation and utilisation (g ollnick 1985). in the base/foundation phase o f training, the overall training quotient (i.e. duration x intensity x frequency) is kept well below7 that threshold tjiat would over­ extend the athlete and lead to signs o f over-reaching staleness and fatigue (carlile 1964; councilman 1968’; hopkins 1993). base training is typically perform ed at intensities ranging from 65-70% o f v 0 2n,„ (70-80% o f maximum heart-rate) for a minimum o f 30 min up to several hr duration each day, with a frequency o f b e ­ tween 7-12 session s/w eek, for as long as possible (i.e. 3-4 m onths) depending on the tim e lag after th e ath­ letes last com petitive phase. w hether base training in the high volumes currently undertaken by elite runners (140-160 k m /w eek), cyclists (500-800 k m /w eek ) and swim mers (50-60 k m /w eek ) is essential to elite perfor­ m ance has not been systematically determ ined. in this respect, it is difficult to explain how7 training up to 4 h r/d a y at speeds which are m arkedly slower than planned com petition pace can possibly prepare the elite swim mer for races which typically last less than 15 min. research is needed to establish whether base training per se results in better endurance perfor­ mances com pared to w7hen the athlete trains at an intensity (or effort) that is m ore specific to th e athletes specialist event from the outset o f a training cycle (h opkins 1993). w hether base/foundation training has any benefit to athletes w hose speciality event has no aerobic com ponent remains speculative. s. transition training t h e second phase o f training w'hose prim e objective is to expose the various physiological pow er systems to sustained exercise at an intensity (or effort) w hich cor­ responds to the athletes highest current steady-state pace. t h e physiological and perform ance enhancing b e ­ sports medicine november 1995 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nefits ascribed to transition training include enhance­ ment o f lac talc kinetics (macrae ct al. 1998; tanaka et al. 1984) and stimulation o f the specific neurological patterns o f muscle fibre recruitment needed during a race (costill 1986; lemond and c ord is 1990). intermittent (or interval) training has been the corner­ stone o f swim training for many decades (carlile 1964; daniels and scardina 1984), although it was not until the 1960’s that the first s p o ils scientists began to study the effects o f different combinations o f work and recovery on physiological system s (astrand et al. 1960; christen­ sen et al. 1960). transition training can be perform ed as continuous steady-state exercise or intermittent work bouts with short rest intervals (brooks and fahey 1985; costill 1986). the intensity o f this phase o f training should correspond to ~85% o f vo<„k« or 90-95% o f the athletes maximal heart-rate, d ie so called aerobic anaerobic th resh old ” (lemond and g ordis 1990), or the athletes b est current race-pace for either a 10 km (running) a flat 40 km time-trial (cycling/triathlon) or 1,500 in (swimming). although exercise prescription based on blood lactate concentrations has becom e pop­ ular with swim mers and more recently cyclists for d e ­ termining the effort o f transition training, there is little scientific evidence to support such practices. an example o f a transition session for a runner or cyclist woidd incor­ porate a thorough 30 min warm-up, followed by 6-8 re­ petitions each o f 5 min duration at the athletes best current race pace for their event, with a maxinumi of 60 sec active recovery (i.e. jogging or low gear spinning). there is no need to measure d ie precise distance covered dur­ ing each work bout; as an athlete gets fitter die)' will merely cover more distance in a given time. transition training should b e perform ed twice a week for the four weeks im m ediately following the base phase. in a dd i­ tion several time-trials over distances less than die ath­ lete’s planned com petitive event may b e undertaken during this time. the athlete should aim to com plete such trials at a pre-planned pace or effort, at close to projected race pace, but not necessarily all-out. 3. speed/power tra ining the final phase o f training which is designed to expose the various physiological systems to maximal or supia maximal exercise at a speed (or efforts) wiiicli are fastei than planned race-pace. s p eed /p ow er training em ploys relatively high intensity work bouts widi long rest periods (coe and miller 1981; moorcroft and temple 1984). the overall volume o f training is low' during this final phase. an example o f such a session for a runner or eve list would involve an extended warm-up, followed by 6-8 re­ petitions o f up to 90 seconds duration with a com plete (i.e. 5 min) active recover)' (i.e. jogging or low' gear spin­ ning) between repetitions. heart-rate monitoring is not a valid technique for determ ining the intensity o f s p e e d / i lower workouts; often an athlete will attain a higher heart-rate (and blood lactate concentration) after the exercise bout. s p eed /p ow er training should be per­ form ed up to three tim es/w eek during the final 21 days before a major com petition. in d ie final 7-10 days im­ mediately prior to an important race, the training load is gradually reduced to nearly zero. as has teen previous­ vouarenssiqq diclophenoc s o d iu m 1 0 0 m g m/3.1/63 ly stressed (h opkins 1993), the lower overall workloads in this phase o f training are achieved by reducing the volume and frequency o f training and not the intensity, b id eed , a recent study (s h cp lcy et al. 1992) found that m iddle-distance runners significantly improved their performance times by sharply reducing then' training volume while maintaining or slightly increasing their training intensity' seven days before a race. this method o f taper was superior to b o d i a reduction in training intensity, and total rest (i.e. no running at all) in the w eek prior to com petition (s h cp lcy et al. 1992). practical research is needed in most endurance sports to determ ine the optimal com binations o f reductions in volume and intensity that will subsequently result in the greatest improvements in performance. when planning a year-round program me for the endurance athlete, the specific physiological dem ands o f the event should be identified and appropriate train­ ing techniques em ployed that will enhance those (ac­ tors that are critical determinants o f performance. it should always be rem em bered that the physiological adaptations to training are closely related to the speed, distance and m ode o f training perform ed d ining repeat­ ed days o f exercise. since there is litde cross-training effect from one type o f exercise to another (costill 1986; wells and pate 1988), workouts should be structiued to develop only the power system s required for the ath­ letes speciality event (h opkins 1993). finally, endurance training is not, and will never be, a purely scientific endeavour. current knowledge ol training practices has evolved mainly through the expe­ riences of many coach es and their charges and not usu­ ally because o f any scientific breakthroughs arising from laboratory-based investigations by sp o ils scien­ tists with top atldetes. future innovations in training techniques, improvements in atldetic performance, and breakthroughs in applied exercise science will onlj be accom plished as a result o f closer working relation­ ships between athletes, coa ch es and sports scientists who possess a com prehensive and practically based knowledge o f specialised events. references 1. agnew i (1976) kiwis can fly. markelforce ltd.. auckland, pp. 187. 2. astrand 1. astrand po, christensen eh. hedman it. (i9 6 0 ) intermittent muscular work. a d a physiologica scandinavia 48: 448-453. 3. astrand po. rodahl k (1977) textbook of work physiology. second edition. mcoraw hill. new york. 4. berqh v. thornstensson a. sjodin b. hullen b. piehl k, karlsson j (1978) maximal oxygen uptake and muscle fiber types in trained and untrained humans. medicine and science in sport 10: 151-154. 5. bock /ik vancaulaert c, dill db. lolling a. hurxthal l (1 928) studies in muscular activity iv. journal of physiology 66: 162-174. 6. bouchard c„ dionne ft. simoneau ja. boulay mr (199-.) genetics o f aerobic and anaerobic performances. exercise and sport sciences reviews 20: 27-58. 7. brooks ga (1985) anaerobic threshold: review o f the con­ cept ami directions for future research. medicine and science in sports and exercise 17: 22-31. 8. brooks ga. fahey td (1985) evercise physiology. human 10 sports medicine november 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) bioenergetics and its applications. macmillan publishing company. new york-. 9. carlile f (1964) athletes aiul adaptation to stress. in: wilt f (editor). run. run. run. track and field news. los altos. california. 10. carter jel. kasch fw. boyer jl. phillips \vii. ross wd (1967) structural and functional assessments o f a champion runner peter snell. research quarterly 38: 355-365. 11. cavanagh pr, williams kr (1982) the effect o f stride length variation on oxygen uptake during distance running. medicine and science in sjiorts and exercise 14: 30-35. 12. christensen eh. hedman r, saltin b (i9 6 0 ) intermittent and continuous running. acta phi/sioldgica scandinavia 50 269-286. 13. (jansen j/' (19/7) effect of physical training on cardiovas­ cular adjustments to exercise in man. physiology reviews 57:779-815. ' 14. coe s. miller d (1981) running free. sidgwick and jackson. london. 15. coetzer p. noakes td. sanders b. lambert ml. bosch ,1.y. ii iggins t. dennis sc (1993). superior fatigue resistance o f elite black south african runners. journal o f applied physiology (in press). 16. conconi f. ferrare m. ziglio pc,. droghetti p, codeca l (1982) determination o f the anaerobic threshold by a non invasive field lest in runners. journal o f applied phusioloau _ 52: 869-873. 1/. 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(..ostill dl (1 9 8 6 ) inside running. basics o f sports physiology. benchmark press inc.. indianapolis. 24. costill dl. branham g. eddy d. sparks k (1971) determinants of marathon running success. internationale _ zeitschrift fur angewandte physiologic 29: 249-254. 25. costill dl. kovaleski j. porter i). fielding ra. king d (1985) energy expenditure during front crawl swimming: predicting success in middle-distance events. international journal o f sports medicine 6: 266-270. 26. costill dl. thomas r. robergs ra. pascoe d. lambert c. barrs. fink wj (1991) adaptations to swimming training: influence o f training volume. medicine and science in sports _ and exercise 23: 371-377. ~/. costill dl. thomason h. roberts e (1973) fractional utili­ sation of the aerobic capacity during distance running. medicine and science in sport 5: 248-252. 28. (.ostill dl. winrow e (1970a) a comparison o f two middle aged ultramarathon runners. research quarterly for exercise and sport 41: 135-139. ~0. coslill dl. winrow e (1 9 /ob) maximum oxygen uptake among marathon runners. archives o f physical medicine and rehai>ilita(ion 51: 317-320. 30. coyle ee coggan a r. hopper mk. wallers tj (1988) determinants o f endurance in well-trained cyclists. journal o f applied physiology 64: 2622-2630. 31. coyle ef. feltner me. kautz sa. hamilton mt. montain sj. baylor am. abraham ld, petrek gw (1991) physiological and biomechanical factors associated with elite endurance cycling performance. medicine and science in sports and evercise 23: 93-107. 32. coyle ef. sidossis ls. horowitz jf. beltzjd (1992) cycling efficiency is related to the percentage o f type i muscle fibers. medicine and science in sports and exercise 24: 782-788. 33. daniels j (1974) physiological characteristics o f champion male athletes. research quarterly 45: 342-348. 34. daniels jt (1985) j physiologist’s view o f running economy. _ medicine and science in sports and exercise 17: 332-338. 35. daniels j. scardina n (1984) interval training ami perfor­ mance. sports medicine 1: 327-334. 36. davies (,. knibbs a (1971) the training stimulus: the effects of intensity, duration and frequency o f effort on maximum aerobic power output. internationalle anyew physiologic 29: 29 )̂~30o. 37. davies ctm, thompson mw (1979) aerobic performance o f female marathon and male ultramarathon athletes. european journal o f applied physiology 41: 233-245. 38. ekblom b (1969) effects of physical training on the oxygen transport system in man. acta pliysiologica scandinavia 328 (supplement) 11-45. 39. faria i (1970) cardiovascular response to exercise as influ­ enced by training o f various intensities. research quarterly 41: 44-50. 11 40. farrell pa. wilmore jh. coyle ef. billing je, costill dl (1979) plasma lactate accumulation and distance running peiformance. medicine and science in sport 11: 338-344. 41. fink wj. costill dl, pollock ml (1977) submaximal and maximal working capacities o f elite distance runners. pari ii. muscle fiber composition and enzyme activities. in: milvy p (editor). the marathon: physiological. epidemiological, and psychological studies. anna/s of the new york academy o f sciences. volume 301, pp. 323-327. 42. fitts rj1 (1977) the effects o f exercise-training on the devel­ opment o f fatigue. in: milvy p (editor). the marathon: physiological. epidemiological, and psychological studies. annals of the new york academy o f sciences. volume 301 pp. 424-430. 43. fox el. bartells c. billings c. mathews d. bason r. webb iv (1973) intensity and distance of interval training pro­ grams and changes in aerobic power. medicine and science in sports 5: 18-22. 44. fox el. bartells c. billings ce. obrien r. bason r, mathews dk (1975) frequency and duration o f interval training programs and changes in aerobic power. journal o f applied physiology 38: 481-484. 45. gollitick pd (1985) metabolism o f substrates: energy sub­ strate metabolism during exercise and as modified by train­ ing. federation proceedings 44: 353-357. 46. ilawley j a, noakes td (1992) peak power output predicts maximal oxygen uptake and performance lime in trained cyclists. european journal o f applied physiology 65: 79-83. 47. hawley ja. williams mm. vickovic mm. harulcock pj (1992) muscle power predicts freestyle swimming perfor­ mance. british journal o f sports medicine 26: 151-155. 48. hellemans j (1993) triathlon. a complete guide for training and racing. reed books. birkenhead, auckland. 49. herbst r (1928) der gastoff'wescliel als mab der koq>er lichen leistung/cihigkeit. deutsches archives fur klunical medizine 162: 33-50. 50. holloszy jo, rennie mj, hickson rc. conlee rk, iiugberg jm (1977) physiological consequences o f the biochemical adaptations to endurance exercise. in: milvy p (editor). the marathon: physiological. epidemiological, and psychological studies. annals o f the new york academu o f sciences. volume 301. pp. 440-450. 51. hopkins wg (1993) new guidelines for hard training. the new zealand coach 2: 16-20. 52. horwill f (1992) periodisation plausible or piffle? modern athlete and coach 30: 11-13. 53. jacobs i (1986) blood lactate: implications for training and sports performance. sports medicine 3: 10-25. 54. kiessling kh. piehl k, lundquisl cg (1971) effect o f phys­ ical training on ullrastructural features in human skeletal muscle. muscle meudyolism during exercise. plenum press. new york. pp. 97-101. 55. kuipers h, keizer ha, de vries t. van rijthoven p wijts m (1988) comparison o f heart rate as a non-invasive determi­ nant o f anaerobic threshold with the lactate threshold when cycling. european journal o f applied physiology 58: 303 306. sports medicine november 1995 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 56. lafontaine tp, londeree br , spath w k (1 9 8 1 ) the maxi mal steady-state versus selected. running events. medicine and science in sports and exercise 13: 190-192. 57. leary wp, w yndham ch (1 9 6 5 ) the capacity for maximum physical effort o f caucasian and bantu athletes o f interna­ tional class. south african medical journal 3 9 : 651-655. 58.lem ond g, gordis k (1 9 9 0 ) greg lemonds complete book o f bicycling. perigee books, putman publishing company, new york. 59. liljestrand g, stenstrom n (19 20 a ) studien uber die physi­ ologies des schwimmens. scandinavian archives for physiology 39 : 1-63. 60. liljestrand o, stenstrom n (19 20 b ) respirationsversuche beim gehenm laufen, skiand• schlittschuhlaufen. scandinavian archives for physiology 39 : 167-206. 61. londeree b r (1 9 8 6 ) the use o f laboratory test results with long distance runners. sports medicine 3 : 201-213. 62. lydiard a , gilmore g (1 9 7 8 ) running the lydiard way. world publications, mountain view, california. 6 3 .lydiard a , gilmore g (1 9 8 3 ). running with lydiard. plodder and stoughton, auckland. 64. macrae hsh, dennis sc, bosch a n , noakes td (1 9 9 2 ) effects o f training on lactate production and removal during progressive exercise in humans. journal of applied physiology 72: 1649-1656. ^ 65. martin d e , vroon dh, may df, pilbeam sp (1 9 8 6 ) physiological changes in elite male distance runners training. physician and sportsmedicine 14: 152-171. 66. morgan dm, baldini fd. martin pe, kohrt w m (1 9 8 9 ) ten kilometer performance and predicted velocity at vosmax among well-trained male runners. medicine and science in sports and exercise 21 : 78-83. 67. moorcroft d , temple c (1 9 8 4 ) running commentary. stanley paul, london. 68. nelson rc, gregor rj (1 9 7 6 ) biomechanics o f distance run­ ning: a longitudinal study. research quarterly 47 : 417-428. 69. noakes td (1 9 8 8 ) implications o f exercise testing for pre­ diction o f athletic performance: a contemporary perspective. medicine and science in sports and exercise 20 : 319-330. 70. noakes td (1 9 9 1 ) lore o f running, third edition. leisure press, champaign, illinois. 71 .noakes td, myburgh k h , schall r (1 9 9 0 ) peak treadmill running velocity during the \ ■ test predicts running per­ formance. journal o f sports science 8 : 35-40. 72. peronnet f, thibault g (1 9 8 9 ) mathematical analysis of running performance and world records. journal of applied physiology 67: 453-465. 73 .pine g (1 9 6 1 ) running wild. w h allen, london. 74.pollock m l (1 9 7 7 ) submaximal and maximal working capacity o f elite distance runners. cardiorespiratory aspects. in: milvy p (e ditor). the long distance runner. a definitive study, new york academ y o f sciences, urizen books, new york, pp. 60-71. 75 ribeiro jp. fielding r a , hughes v. black a , bochese ma, knuttgen h g (1 9 8 5 ) heart rate break point may coincide with the anaerobic and not the aerobic threshold. international journal of sports medicine 6: 220-224. 76. robinson s, edwards ht, dill d b (1 9 3 7 ) new records in human power. science 85 : 409-410. 77 .rowell l b (1 9 8 6 ) human circulation regulation during physical stress. oxford university press, new york. 78. sciltin b (1 9 6 9 ) physiological effects o f physical condition­ ing. medicine and science in sports 1: 50-56. 79. saltin b, astrand p o (1 9 6 7 ) maximal oxygen uptake in athletes. journal o f applied physiology 23 : 353-358. 80. scrimgeour a g , noakes td, a dam s b, myburgh k (1 9 8 6 ) the influence o f weekly training distance on fractional uti­ lization o f maximum aerobic capacity in marathon and ultra marathon runners. european journal o f applied physiology 55 : 202-209. 81. shephard r (1 9 6 8 ) intensity, duration and frequency oj exercise as determinants o f the response to a training regi­ men. internationalle angew physiologie 26 : 272-278. 82. sjodin b, jacobs i (1 9 8 1 ) onset o f blood lactate accumula­ tion and marathon running performance. international journal o f sports medicine 2: 23-26. 83. sjodin b, svedenhag j (1 9 8 5 ) applied physiology of marathon running. sports medicine 2: 83-99. 84. shepley b, macdougall jd, cipriano n, sutton jr, tamopolsky m a, coates g (1 9 9 2 ) physiological effects o f tapering in highly trained athletes. journal o f applied physiology 72: 706-711. 85. tanaka k , matsuura y (1 9 8 4 ) marathon performance, anaerobic threshold, and onset o f blood lactate accumulation. journal o f applied physiology 57: 640-643. 86. wells cl, ilecht lh, krahenbuhl gs (1 9 8 1 ) physical char­ acteristics and oxygen utilization o f male and female marathon runners. research quarterly for exercise and sport 52 : 281-285. 87. wells cl, pate rr (1 9 8 8 ) training for performance of pro­ longed exercise. in: lamb dr, murray r (e d ito r s), perspectives in exercise science and sports medicine volume 1. prolonged exercise, benchmark press, indianapolis, pp. 3 5 7 -3 9 1 .' 88. wilmore j h (1 9 8 4 ) the assessment of and variation in aer­ obic power in world class athletes as related to specific sports. a merican journal of sports medicine 12: 1 2 0 -1 2 /. 89. wyndham cii, strydom nb, van rensburg a j , benade a js (1 9 6 9 ) physiological requirements for world-class perfor­ mances in endurance running. s o u t h african medical journal 4 3 :9 9 6 -1 0 0 2 . 90. zur megede and hym ans r (1 9 9 1 ) progression o f world b e st performances and official i a a f world records. international athletic foundation, monaco, pp. 1-705. □ ( continued from page 1) tion, not only o f human exercise physiology but also the specific requirements o f different sports. dr maurice mars, him self an international athlete and regular com ­ petitor in the ‘duzi and other canoe marathons, has researched the energy cost o f portaging the canoe on either the preferred or the weaker shoulder. he shows, not unexpectedly, that portaging the canoe substantially increases the energy cost o f running but that the increase is greater when the weaker shoulder is used because there is less control o f the movement o f the canoe. he concludes that canoeists need to train for portaging and provides a simple calculation to assist canoeists in calcu­ lating the running speed they should choose when portaging. his elegant study shows how practical ques­ tion are open to scientific solution to the benefit o f the athletes in that particular sport. to promote physical activity and sport, we must also research the possible health benefits o f regular physical activity. three colleagues from the university o f the orange free state have provided a valuable metanalysis review o f the effects o f exercise on depression. their analysis suggests that exercise has a significant effect in reducing depression and that this effect is independent o f age and health status. this information is particularly valuable for although we usually prescribe exercise for its physical benefits, it may well b e that the greater value of regular physical activity may b e pn our moods and em o­ tions. i trust that this issue o f the journal will inspire you fur­ ther in your personal contribution to south african sports medicine and sports science. the 1999 rugby world cup is just more than 3 years aw'ay. how' wall each o f us con­ tribute to insure that the william webb ellis trophy stays in south africa in the first decade o f the next millennium? professor tim noakes professor in the liberty life chair o f exercise and sports science 12 sports medicine november 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) south african journal o f sports medicine instructions for authors material submitted for publication in the sajsm is accepted on condition that it has not been published elsewhere. the management reserves the copyright o f the material pub­ lished. all authors must give consent to publication, and the sajsm does not hold itself 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" ft f* r e g ^ f f i w o ? s d b o f d t m l s i droad), randjespark, midrand 1685 ’ ' " r e p a ril'-g e l 100 g contains: a escin 1,0 g; d ie th yla m in e sa licylate 5,0 g. reg. no. g /1 3 .9/2367[o-j r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the metabolic demand of portage in kayak marathons m mars summary portage forms an integral part o f som e long distance kayak races. the metalmlic demands o f portaging a sin­ gle person racing kayak were investigated in 15 subjects who regularly participated in kayak marathons. subjects completed 6 minute treadmill runs at 8 km/hr and at ??'/> gradient, both unloaded and carrying a 14.1kg kayak. during the portage run, the kayak was transferred from one shoulder to the other after 3 minutes. kaycikers are shown to have a preferred shoulder with which they are more efficient at portage. in comparison with running in the unloaded state, portage o f a kayak o f this mass on the preferred shoulder increases mean oxygen uptake by. 4 47 ± 151 ml.min1 and mean heart rate by 15.4 beats/min. on the weaker shoulder, significantly greater increases o f both oxygen uptake 590 ± 139ml.min' (p < 0 .0 1 ) and heart rate 20.5 beats/min (p < 0 .0 5 ) occur. the increase in oxygen uptake on the weaker shoulder is ascribed to lack o f stability o f the kaycik dur­ ing portage and consequent loss o f running efficiency caused by balancing manoeuvres. . 1 .s few kayakers include portage in their training programme, a simple method o f estim ating optimal p orta ge p ace is proposed. introduction portage is ail integral part o f long distance canoe and kayak racing. it is defined as, “ the earn ing o f boats or goods between two na\igablc waters” .' while portage is usually undertaken over short distances to avoid a dan­ gerous or non navigable part o f a river, an overland route cutting across an oxbow may be quicker than staying in the water and paddling. portage therefore becom es part o f race strategy in som e long distance river races. one such race is the msinduzi canoe marathon. this annual 3 day event from pietcrm aritzbiug to durban on approximately 130 km o f the msinduzi and mgeni rivers in kwazulu natal, south africa, attracts over a 1 000 com petitors. the tide o f d ie race is misleading as fibreglass racing kayaks and not canoes are used, and because o f various gorges, waterfalls, and oxbows in the river, several sections o f the race are overland, with portages o f up to 10 km being encountered.' the ratio o f paddling to numing is determ ined by the canoeists’ relative skills and the level o f the water. in years o f drought, low water rules allow com petitors to portage alm ost two thirds o f the course. t h e energy dem ands o f portage have not been estab­ lished. it has been shown that the energy requirement o f moving a known mass over a fixed distance is not con­ stant, and is dependent on the method o f c a r r ia g e ."5 carrying a single person racing kayak on the shoulder address for correspondence d r m a u rice m ars department o f physiology university o f natal medical school b ox 17039 congella 4013 south africa while on d ie run requires learned skills o f balance, as one arm is removed from the normal numing action and is used to steady the kayak. this may further increase energy e x p e n d i t u r e , hi addition, most canoeists appear to have a dominant shoulder on which they prefer to portage. this preference inav be due to shoulder asym­ metry, and be simply a matter o f com fort, or if may be the result o f a difference in efficiency o f carriage b e ­ tween shoulders. despite favouring one shoulder for portage, the kayak is usually transferred from shoulder to shoulder every two to three minutes on long portages. while portage potentially forms a major component o f the race, training for portage is largely empirical. a 15 time winner o f the event proposes two training pro­ gram m es lor portage. for the com petitive p ad d lcr/run ­ ner aiming at winning the race, it is suggested that run­ ning with the canoe shoidd be included as part o f the numing training, and should start 3-4 m ondis before the race. t he numing programme outlined for the aver­ age competitor, however, makes no mention o f portage. ' it is estim ated that 95% o f p ad dlcrs follow uiis sec­ ond option and do not run with a boat on their shoulder in training. a reason for this, is that it is hazardous to run with a 5.2m kavak on one’s shoulder on urban roads. the problem encountered by tliis group is esti­ mation o f the optimal pace at which to jiortage during the race. the aims o f this study were to investigate the energy expenditure o f portage, to determine whcuicr d ie energy requirements o f portage are constant on either shoulder and to propose a sim ple means o f predicting a suitable race portage pace, based on pre-race numing training. method fifteen m ales w ho rcgularlv com p ete in kayak marathons, vohuiteercd to take part in this study which was p erform ed 6 w eek s prior to the msinduzi marathon. all tests were perform ed in d ie morning and no exercise had been undertaken prior to testing. each subject gave informed consent and com pleted a ques­ tionnaire detailing his kayaking experience ineluding the number o f seasons o f com petitive participation, his natal canoe union grading and the number o f msinduzi marathons entered. their com petitive numing experi­ ence and active participation in o d ie r sports was also recorded. subjects nominated their preferred shoulder o f portage before testing. the subjects were exercised on a m otorised tread­ mill im der each o f the following four conditions. 1. running for 6 minutes at 8 k m /h r at a 3% gradient. 2. running for 6 minutes at 8 k in /h r at a 3% gradient wearing a backpack loaded to 14.1 kg with sand bags. 3. riuuiing for 6 minutes at 8 k m /h r at a 3% gradient carrying a single person racing kayak weigliing 14.1 kg. the kayak was first carried on die right shoulder and after diree minutes, transferred to die left shoulder. 4. running to exhaustion on a fixed speed, increasing gradient protocol. each exercise protocol was followed by a 10 minute recovery period with d ie subject seated oil a chair on sports medicine november 1995 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) th e treadmill. a balanced order experimental design was used in w hich 8 subjects wore the backpack first and 8 subjects carried the kayak first. oxygen consumption (voa) was record ed throughout th e four exercise protocols and rest periods and was m easured using open circuit com puterised spirometry, (oxycongamma, myjnhardt). calibrations were per­ formed before ea ch 'test. t h e average readings o f the last 30 seconds o f each exercise protocol were used for analysis. h eart rate was recorded using a beckman electrocardiograph coupled to the oxycon. all tests were carried out in an ambient temperature o f 22-24°c. t h e treadm ill speed o f 8 k m /h r was ch osen after d is­ cussion with the subjects, following a pre-test familiari­ sation practice run. there was consensus that 8 k m /h r at a slight incline, represented a com fortable portage pace, and that it was probably close to the average pace maintained by the subjects on a long portage. statistical analysis was by analysis o 1 variance, duncan’s m ultiple range analysis, and paired t-test, where appropriate, with significance taken at the 9 5 /o probability level. descriptive statistics are presented as m eans and one standard deviation. results t h e average age o f the subjects was 31.5 ± 7 . 3 years, range 21-42 years. canoeing experience ranged from 3 to 15 years averaging 8 ± 3.5 years, with an average o f 6 com pleted msinduzi marathons. there were 3 a grade paddles, 9 b grade and 3 c grade paddlers. g rading is based on the ratio o f the com petitors finish­ ing tim e to that o f th e race winner. t h e a grade, co m ­ prises those w ho finish within th e winner’s tim e plus 10%, b grade, is betw een 111% and 125% ol the win­ ner’s time, and c grade, between 126% and 140% o f the winner’s time. all but one o f the subjects was involved in som e form o f regular running training, and only one subject included portage in his training. twelve subjects indicated that they preferred to portage on their right shoulder. o f these, 10 subjects were right hand dominant. the remaining three sub­ je cts were left hand dom inant and preferred their left shoulder for portage. t h e mean vo,... was 4 218 ± 3 3 3 m l.m in ', range 3 51 3-45 86 m l.m in 1 or 55.7 ± 5.4 m l.k g 1 .m in 1 (45-64 m l.k g'.m in ’), with a mean m aximum heart rate o f 188 ± 11.2 beats per minute. oxygen consum ption ex­ p ressed in absolute terms and as a percentage o f maxi­ mum, and heart rate under the different exercise con ­ ditions, is shown in table 1. carriage o f th e additional mass o f 14. l k g resulted in increases in oxygen consum ption of 4 34 ± 154 m l.m in 1 with the backpack and 4 46 ± 150 m l.m in 1 and 590 ± 138 m l.m in 1 with th e kayak on the preferred and weak­ er shoulder respectively. statistically significant differ­ ences in oxygen consum ption (p < 0.01) and pulse rate (p < 0.05) were noted when comparing shoulders during kayak portage. t he differences in oxygen consumption and pulse rate between carriage ol the backpack and portage on the preferred shoulder were not significant. w hen divided according to their canoe union grading b a se d on race perform ances, a grade subjects had a sig­ nificantly higher vo*,,,,, (62.6 ± 5.0 m l.m in 1.k g ') than those in b (55.0 ± 5.4 m l.m in '.k g ') p < 0.05, and c grade (50.9 ± 10.8 m l.m in 1.k g ') p < 0.05. they p er­ form ed at a significantly lower percentage o f their max­ im um oxygen consumption, than their b and c grade counterparts, in b oth the loaded and unloaded states, p < 0.01 (table 2). running unloaded, th e percentage o f voa,,,,,, utilised d id not differ significantly between b and c grades. u nder load however, c graders used a significantly greater percentage o f their v( ) ■: x than b grade subjects p < 0.05. comparing shoulders, th e increase in oxygen uptake expressed as a %vol!,„„x required for portage on the t a b l e 1. o x v q e n c o n s u m p tio n in m l a n d a s a p e r c e n t a g e o f v o s ^ , a n d p u l s e r a te in b e a ts p e r m in ute, w h ile ru n n in g in th e u n lo a d ed s t a t e a n d w ith t h e b a c k p a c k o r k a y a k a r e e x p r e s s e d a s m e a n s a n d o n e s ta n d a r d d e v ia tio n ( n = 1 5 ) . t h e in c r e a s e in b o th o x y g e n c o n s u m p tio n a n d h e a r t r a te w a s s ig n ific a n tly h ia h er w ith v o r ta a e o n th e w e a k e r s h o u ld e r th a n o n th e p r e fe r r e d s h o u ld e r p < o .o o . v 0 2„ „ m l.m in' %voa.,..« max h eart rate running unloaded running with backpack kayak (preferred shoulder) kayak (weaker shoulder) 2 537 ± 229 2 9 7 1 ± 185 2 984 ± 201 3 1 2 8 ± 236 60.6 ± 7.4% 70.9 ± 6.5% 71.2 ± 7.7% 74.7 ± 8.5% 137.5 ± 11.2 150.2 ± 11.2 152.9 ± 13.1 158.2 ± 13.1 table 2 . aqe, v o and oxygen consumption as a percentage o f vosma,, according to grading o f paddlers based on their performances in races, expressed as mean and one standard deviation. the a grade paddlers have a significantly higher v 'o a„„ than the other grades (p < 0 .0 5 ), and pê orr^ rat/ ŝ f ct '^ lower percentage o f their v o ^ in both the loaded and unloaded states (p < 0.01) . under l° a f ’ ^ e c arade noddies use a siqnificantly greater percentage o f their vu-,™ than b grade paddlers (p < 0.05). a grade (n = 3) b grade (n = 9) c grade (n = 3) all ( 1 1 = 15) a ge (years) voa,,,̂ (m l.m in 1) voa,,,,,, (m l.k g '.m in 1) voa as % o f vozmm unloaded backpack kayak (preferred) kayak (weak) 25.7 ± 9.3 4 4 22 ± 356 6 2.9 ± 3.5 5 0.3 ± 7.4% 61.4 ± 5.0% 60.8 ± 8.5% 63.2 ± 5,8% 30.6 ± 8.9 4 2 7 1 ± 399 55.0 ± 5.4 62.0 ± 7.4% 7 1.5 ± 5.4% 71.7 ± 4.6% 74.7 ± 6.2% 40.0 ± 3.5 31.5 ± 7.3 3 8 55 ± 5 4 2 4 218 ± 333 51.0 ± 10.8 55.8 ± 5.5 66.4 ± 6.9% 60.6 ± 7.2 78.3 ± 8.1% 70.8 ± 6.6 80.2 ± 15.1% 71.2 ± 7.5 85.9 ± 13.2% 74.6 ± 8.7 16 sports medicine november 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) weaker shoulder was significantly greater within the b and c grades p < 0.05 and approached significance in the a grade p = 0.057. within each grade, there was no d ifference in oxygen consumption when carrying the backpack or portaging on the preferred shoulder. discussion the changes in oxygen uptake and heart rate w hile run­ ning with the backpack, are shown to b e similar to those observed for portage o f a kayak on th e preferred shoulder which on average required an increase in oxv gen consumption o f 10% o f voa™, and a 13-15 beat per minute increase in heart rate. t he similarity in the m eta bolic requirem ents o f b ackpack carriage and portage on th e p referred sh ou ld er suggests that removal o f one arm from the normal running style d oes not on its own significantly influence energy consum p­ tion under these conditions o f loading. t h e dem ands o f portage differed significantly b e ­ tween shoidders, with portage raising heart rate on average 15 beats per minute on the preferred shoulder and 20 beats per minute on the weaker shoulder. the difference may be explained by a description o f the changes in portage technique that occurred in all sub­ jects. on the preferred shoulder the kayak appeared to b e “ lo ck e d ” on th e shoulder. during th e run, the kayak did not bounce, and it’s longitudinal axis remained rel­ atively constant with minimal vertical or horizontal drift. t h e free arm assumed an apparently normal p osi­ tion during d ie run. on the weaker shoulder, the kayak was less firmly positioned on d ie shoulder. bounce on the shoulder was obvious, being both heard and seen. t h e kayak tended to oscillate from sid e to sid e on it’s long axis, and the free arm was used in a circum duction m otion with the shoidder abducted ± 40°-60°. stride length and width usually shortened and widened. it w’ould appear that th e increase in m etabolic rate was due to primarily to corrective balancing manoeuvres. t h e percentage increase in oxygen uptake on the weaker shoidder is similar to th e findings o f legg et al who investigated th e energy requirem ents o f backpack loading and bilateral shoulder carriage. both heart rate and oxygen uptake were significantly higher for bilater­ al shoulder carriage, which was attributed to the raised position o f the arms causing an extra strain on the car­ diovascular system, increased muscular activity o f (lie shoulders and arms, and use o f th e muscles o f the upper b ody to com pensate for lateral bending o f the trunk during load carriage.3 as m ight be expected in an endurance sport, d ie grading based on race perform ance relates to maximal oxygen uptake, with the different grades each reflecting a 10% difference in relative oxygen consumption during portage at a set pace. the experimental portage pace o f 8 km /hr, although chosen by consensus o f the subjects, resulted in the c graders perform ing at 86% vo-w. one subject required 94% v02„u« for carriage on liis weaker shoulder, a level that exceeded his ventilator}' thresh­ old. how' can d ie data obtained in this study be used to assist those who d o not include portage in their train­ ing, to select an appropriate race portage p a ce? based on th e information that portage o f an average mass sin­ gle kayak will increase heart rate by approximately 15 20 beats p er minute, the following sim ple rule o f thum b is proposed. it is suggested that com petitors obtain their heart rate at the end of an 8 to 10 km time trial or hard train ing run. on a subsequent training run, they should monitor their pulse rates at slower running speeds, until they find the pace which maintains the heart rate &t 15-20 beats per minute below their heart rate obtained at the end o f th e tim e trial. this should rep­ resent the appropriate race portage pace. it is not advo­ cated that subsequent running training be undertaken at portage pace, but rather that the com petitor learns to gauge the difference between training pace and portage pace. an alternative wrould b e to carry7 a w'eighted back­ pack on training runs. for th ose wiio use portage in their training, perfor­ m ance m ight b e improved by improving the stability7 o f the kayak on th e weaker shoulder, thereby reducing unnecessary energy expenditure. although regular training o f portage is both difficult and hazardous in urban areas it should logically be included in training program mes as a sport specific task, to im prove learned m otor skills and to provide correct m uscle loading at race pace. references 1. the oxford reference dictionary. e d j m hawkins, clarendon press oxford, 1986: p650. 2. pennefather r. canoeing in south africa. southern, 1991: p i 02. 3. legg sj, ratnsey t, knowles dj. the metabolic cost o f back­ pack and shoulder carriage. ergonomics 19 92 : 3 5 : 1063 1068. 4. d atta sr and ramanathan nl. ergonomics comparison o f seven modes o f carrying load on a horizontal plane. ergonomics, 19 71 ; 14: 269-278. 5. kram r. carrying loads with springy poles. j a ppl phus 1 9 9 1 ;7 1 :1 1 1 9 -1 1 2 2 . n sports medicine november 1995 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) verw nr g 2 9 6 3 <a c t /w e t 101’ 19f‘ celestone® § soluspan® 5 ml sterile multiple dose vial j.i 5 r«tnojv«wtw g : > (act/we<101.19«!>l6 celestone' ■ < soluspan’’ lic 1 ml ampoule, noi reg. no celestone* soluspan* 2 ml sterile multip1 dose vial s c h e r a g (pty) limited r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) g l e n b a r r pecialist publication so u t h a f h il a x to u r x a l i lf sports medicine v o lf n o i j u n t m b free to medical doctors contact: glenbarr publishers 25 bompas road, dunkeld west, 2196. tel: (011) 442-9759 fax: (011) 880-7898r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) die invloed van oefening op depressie: ’n meta-analise e pretorius departement menslike bewegingsktmde jc jansen van rijssen universiteit van die oranje-vrystaat jm van zyl departement wiskundige statistiek universiteit van die oranje-vrystaat abstract a meta-analysis was done on the existing literature regarding the influence o f exercise on depression. the results o f 4 0 studies, with a total o f 3 225 experimental subjects were coded by means o f 12 research questions. the effect sizes were calculated and the statistical signif­ icance o f the results was tested by means o f an a n o v a analysis. a mean o f 94 effect sizes were found with a z value o f -6,736. this indicates a highly significant (p < 0 ,0 0 1 ) reduction in depression with exercise. i t was also found that neither gender nor the health status nor age play any role in the effect o f exercise on depression. inleiding d epressie kan vandag m et reg besk ou w ord as ’n wesenlike p robleem in d ie sanielewing en wel om die volgende redes: • d it is ’n geson dh eidsp rob leem vanwee d ie hoe voorkomssyfer daarvan.1 • dit is ook ’n sosio-ekonom iese probleem vanwee behandelingsm etodes wat hoofsaaklik bestaan uit m edikasie, psigoterapie eii hospitalisasie o f ’n koin binasie van al drie. dit bring ’n ekonom iese las m ee en dikwels o ok d ie onttnekking uit d ie gem eenskap en werksom standighede wat verlies aan manure beteken ." d epressie is so algem een dat 15% tot 20% van alle vol wassenes op enige tydstip sim ptom e van depressie ondervind. by minstens 12% sal d epressie op een o f ander tydstip in hulle lewens so em stig wees dat behandeling nodig sal wees, i erwyl volgens skatting dit vir 75% van h ierd ie groep nodig sal w ees om in psigia triese hospitale opgeneem te w ord.1 d ie waarde van oefening as m etod e in d ie kliniese evaluering, voorkom ing en rehabilitering van siektetoe stande, het eers gedurende die sesligerjare vanuit d ie verskillende navorsingsvelde aandag verkry.' d it was egter eers in die laaste twee d ekad es dat navorsers belangstelling begin toon het in d ie psigologiese effek van oefening en veral d ie invloed daarvan op d epressie.' d ie invloed wat oefening op depressie het, w ord al m eer en m eer deur navorsers in verskeie vakdissiplines in die soeklig geplaas. d ie bevindinge wat deur verskil len d e navorsers in d ie 1 iterat uur opgeteken is, is egter dikwels nie versoenbaar nie. in som inige van d ie studies word aangetoon dat oefenin g w el ’n antid epressiew e invloed h e t.24" 67 h ierdie invloed kan selfs op indirekte wyse m eehelp tot d ie vermindering van depressie. daar word bew eer dat oefening soos d ra f ook as psigoterapie gebraik sou kon word in d ie behandeling van depressie.6 h ierdie outeur m otiveer sy stelling soos volg: d ra f los n ie die persoon se eksistensiele problem e op nie, maar dit bied wel tydelike verligting wat aan d ie persoon d ie geleenth eid b ie d om sy problem e op te los (soortgelyk aan ’n aspirien vir d ie verligting van hoofpyn). a nder studies toon geen b eteken isvolle invloed van oefening op depressie aan m e.8'9 h ierdie teenstrydigheid in navors ingsresultate kan w aarskynlik aan tw ee oorsake toegeskryf word: • oefening word nie d uidelik gekwalifiseer en gekwan tifiseer nie. • heelwat navorsers gebruik d ie tradisionele verhal ende m etode van navorsing wat som s lei tot subjek tiewe interpretasies en alleidings. d ie b ree d oel van hierdie studie was om, m et behulp van meta-analise, ’n d eeglik verantwoorde statistiese integrering van resente navorsingsresultate oor die invloed van oefening op depressie te maak. om verder d ie rol wat sekere geidentifiseerde veranderlikes m et betrekking tot d ie invloed van oefening op depressie speel, na te gaan. meta-analise meta-analise h et ’n kwantitatiewe aanslag op navorsing en maak gebruik van ’n,verskeiflenlieid statistiese teg n ieke vir die selektering, klassifisering en samevatting van inligting wat verkry is uit verskeie em piriese stud­ ies. daar bestaan ’n h ele aantal tegnieke wat algemeen aanvaar word en waarmee verskillende tipes statistiese gegewens vanuit verskillende em piriese on dersoeke na een maatstaf, die sogenaam de effekgrootte (effect size), herlei kan word. d ie m etode wat gebruik word in die berekening van d ie effekgrootte, is aflianklik van die tipe statistiek soos gerapporteer in elke studie wat by d ie meta-analise betrek word. tegniese problem e word som s ondervind in die samevoeging van resultate van eksperim entele studies. d ie red e hiervoor kan moont lik w ees dat statistiese toetse nie altyd d ie sterkte van d ie verwantskap o f d ie effek van belang aantoon nie en daarom beveel navorsers10'1112 aan dat resultate gekom bineer m oet word, m et aanduiding van effekgrootte. in hierdie studie is van verskillende out.eurs" se for m ules gebruik gem aak om d ie effekgrootte te bereken. beskrywende statistiek word gebruik om d ie navors­ ingsresultate te kondenseer, op te som en vereenvoudig tot ’n enkele resultaat. metode ’n literatuursoektog is geloods m et behulp van geiden­ tifiseerde sleutelw oorde (oefening/exercise; fik s h e id / physical fitness; draf/jog; d epressie/depression ; ge m oed /m ood ; angs/anxiety) wat m et behulp van reke naarsoektogte op d ie volgende databasisse, t’sychoinfo en m esh gemaak is. tydens d ie voorondersoek is ’n kodeervorm ontwikkel en verfyn; dit vorm d ie sleutel tot sukses in meta-analise. in die verwerking van die algehele data is d ie z-toets gebruik om vas te stel o f die totale g em id d eld e effekgrootte van depressie beteke20 sports medicine november 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nisvol verskil van nul. a s ’n gem id d eld e effekgrootte in hierdie studie betekenisvol verskil van mil, word d ie nulhipotese van geen effek verwerp. ’n waarskynlik heidspeil van (p < 0,05) is gebruik om te bepaal o f d ie analise statistics betekenisvol is, al dan nie. d ie veranderlikes word m et behulp van beskry wende statistiek weergegee in d ie vorm van tabelle vir die versk illen de kategoriee van d ie gean aliseerde veranderlikes en sluit d ie volgende in: d ie aantal efiek groottes in d ie onderskeie kategoriee, d ie gem id deld en standaardaiwyking van d ie betrokke effekgroottes, asook d ie z-waardes onderskeidelik. d ie pearson-pro dukm om entkorrelasie, asook eenrigting ano\a’s is gebruik in d ie verwerking van gegewens. resultate ’n totaal van 40 studies is gebruik om 94 effekgroottes van depressie te bereken. d ie totale aantal proefper sone wat betrek is, is 3 225 (eksperim entele, kontrole en vergelykende groepe). d ie beskrywende statistiek m et betrekking tot d ie invloed van oefening op d epressie word in tabel 1 aangedui. d ie gem id deld van d ie 9 4 effekgrootte oor die invloed van oefening op depressie is -0,5907, m et ’n z waarde van -6,736, wat h oogs betekenisvol (p < 0,001) is en aandui dat die eksperim entele groep wat oefening gedoen het, betekenisvol van d ie kontrolegroep verskil en ’n laer gem id d eld e depressietelling het. u it d ie resu 1 tate kan dus gekonstateer word dat oefening ’n verlagende invloed op depressie het. h ierdie resultaat korreleer m et d ie van vorige navorsers2131415'61718 dat oefening ’n antidepressiewe effek het. daar bestaan ook ’n negatiew e k orrelasie (r = -0,6672) tussen depressie en iik sheid wat h oogs betekenisvol is (p < 0,01). ’n negatiewe korrelasie dui daarop dat namate die proefpersone fikser gew ord het, hulle m inder d ep ressief was. om te bepaal watter proelpersoon-pop ulasie die m eeste baat gevind h et b y oefening in die verlaging van depressie, is vier veranderlikes aange spreek, naam lik ouderdom , geslag, gesondheidstoes tand en d ie depressie van d ie proelpersone. tabel 1 beskrywende statistiek van depressie ten opsigte van die totale groep totale groep aantal effek­ x sigma z-waarde groottes totale data 94 -0,5907 0,8502 -6,736* * p < 0,001 ouderdom ouderdom skategoriee is ingesluit om dat b aie van d ie gek od eerd e studies m e d ie gem id d eld e ouderdom van proelpersone aangegee h et nie, maar tog genoegsam e inligting verskaf h et om d ie proelpersone volgens oud erdom m e in d ie verskillende kategoriee te kon verdeel. die ouderdom skategoriee wat gebruik is, is kinders (jonger as 18jaar), jon k (tussen 18 and 25 jaar) en mid deljarig (26 jaar en ouer). statistiek m et betrekking tot die invloed van oefening op depressie b y d ie verskil­ len d e ou d erd om sk a tegoriee, w ord in ta bel 2 weergegee. d ie m eerderheid van effekgroottes is verkry van d ie jong ouderdom skategorie 18 tot 25 jaar (48,9%) en die iniddeljarige groep wat vir d ie d oel van h ierdie ontled ins gestrek h et van 26 jaar en ouer (46,7%). d ie eenrigting anova vir d ie vergelyking van d ie gem id d eld e efifekgrootte van oefening op depressie tussen d ie verskillende ouderdom skategoriee, was nie betekenisvol nie (f9,89 = 0,8505; p = 0,4307). die z-waardes in t’abel 2 toon dat ’n hoogs betekenis volle verlaging van depressie deur oefening (p < 0,001) by al d ie ouderdom skategoriee gevind is. daar was egter net vier effekgroottes by kinders (jonger as 18 jaar), wat d it m oeilik maak om d ie verskillende groepe m et mekaar te vergelyk. daar is ook ’n negatiewe kor­ relasie tussen d ie verskillende ouderdom skategoriee en d ie effekgroottes vir depressie (r = -0,1068) gevind, m aar d it was n ie betek en isvol nie. d ie fe it dat depressie deur m idd el van oefening b y alle ouderdom s groepe verlaag word, word ondersteun deur d ie studie van m cdonald en h odgdon .19 t a b e l 2 beskrywende statistiek van depressie ten opsigte van ouderdomskategoriee ouderdomsgroep aantal effek­ groottes x sigma z-waarde kinders 4 -0,6510 0,2587 -5,033* jonk 45 -0,4658 0,6412 -4,873* m iddeljarig 43 -0,7032 1,0632 -4,337* totaal 92 -0,5848 0,8582 -6,536* | * p < 0,001 geslag geslag as veranderlike is in berekening gebring om te bepaal o f daar ’n verskil is in d ie invloed van oefening op depressie by mans en dames. som m ige van d ie gekod eerd e studies het in gebreke gebly om aan te toon wat d ie geslag van d ie proelpersone is en in daardie geval is d ie proelpersone gekodeer as manlik/vroulik. in tabel 3 word d ie resultate verstrek. allioewel d ie vrouens (z = -5,130; p < 0,001) b eter as d ie mans (z = -1,986; p < 0,05) gerespondeer het, toon d ie eenrigting a n o w dat daar geen betekenisvolle ver­ skil tussen d ie drie groepe is nie (fg g 1 = 0,3493; p = 0,7061). d it dien verm eld te word d a l slegs 19 effekg­ roottes (20,2% van d ie totaal) vanuit manlike proelper­ sone verkry is, wat m oontlik d ie vergelyking van resul­ tate tussen d ie groepe kan beinvloed. d ie d erd e kate gorie van m a n lik /vrou lik dui ook op d ie a ntid e­ pressiewe invloed wat oefening op b eid e geslagte het (z-waarde = -5,236; p < 0,001). h ierdie resultate word ondersteun deur verskeie navorsers.2019 t a b e l 3 beskrywende statistiek van depressie en geslag geslag aantal effek­ groottes x sigma z-waarde manlik 19 -0,5999 1,3170 -1,986* vroulik 39 -0,5091 0,6197 -5,130** m anlik/ vroulik 36 -0,6742 0,7726 -5,236** totaal 94 -0,5907 0,8502 -6,736* * p < 0,05 | ** p < 0,001 sports medicine november 1995 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) gcsondhcidstoestaiul die gesondheidstoestand van die proefpcrsone is in twee katcgoriee vercleel, naainlik oenskynlik gesondc persone (dit wil sc persone met geen g eiioleeid c psigologiese o f patologicsc ioeslande ol b cid e nie) en ongesondc persone (dil wil se persone met g cn otccid e en gediagnoseerde ldagtes, pstgologics of patologies van aard). h ierdie resukate word in tabel 4 wcergcgec. bcide die gesondc en ongesondc proefpcrsone se depressie het bctekciiisvol verlaag (p < 0,001). die ongesondc groep se z-w aanlc (-4,977; p < 0,001) is die klcinstc, niaar geen bednidende vcrskil tnsscn die twee groepe is met bclnilp van die cciirigung anova gevind nie (f^ g o = 0,2731; p = 0,6025). uit (lie b csliid cruig van die gck ond ensecrd c katc goriec van gesondc versus ongesondc proefpcrsone, blvk (lit dat ook by gesondc persone depressie deur oefening verlaag kan word. soim nigc studies en oorsi gartikcls nit die literatuiir bcw cer dat oefening net ’ii invloed liet op persone wat reeds d e p re ss icf i s ." ’'" 1 h ierdie meta-analise dni daarop dat depressie ook by oenskynlik gesondc persone bctekciiisvol deur oefening verlaag kan word. h ierdie ajlciding word ondcrstcun deur folkins en north. tabel 4 beskr\a\teni)e statistiek van depressie ten opsigte van oenskynlik gesonde teenoor ongesoivde proefpersonii gesondlieids toestand aantal eltck groottes sigma z-waardc g esond 54 -0,5511 0,8783 -4.611* ongesond 40 -0,6442 0,8186 -4,977* totaal 94 -0,5907 0,8502 -6,736* * [> < 0,001 bespreking daar bestaan verskeie psigologiese teoriec cn bcnader ings ten o])sigtc van genioedsverstcnrings. ten einde n verklariiig tc b ied \'ir die antideprcssiewc working van oefening word die verskillende teoriec, wat die oorsake van depressie p robecr vcrklaar, korlliks niteengesit. • n curofisiologicsc faktorc wat predisponcrciid lot depressie optrec, is n nnwe cn intcressan tc navor singsveld waaruit die biogenc-aniicne-, hormoon wanbalanscn clel<trolie 1 1 i i pot c s c s hulle ontstaan gcliad het. aanhangers vail hierdie sienings is oortn "ig daai*van dat die basiese oorsaak van gemoeds\'c r steurings in die sentralc seniiw cestelscl gelee is.' ~ allioewel die p rcsicsc nem ofisiologiese mcganismes wat m eebring dat oefening ii verlagende invloed op depressie het, nog nie b o alle twyfel vasgcstel is nie. het navorsers soos taylor et al.m bevind dat oefening verantwoordclik is vir ’n verhoogde sinaptiese vrys tclling van byvoorbceld katesjolamicnc in die lig gaam. kateslojamienc is ’n groep vtui oordragstowwe wat deur neurone in n sinaps viygcstcl word en wat ii rol in die gelciding van senuwee-inipulsc specl. aanslnilcnd hicrby kan melding gemaak word van die studies van e beil cl a l.’1' en post ct a l.'1 wat bevind het dat die aniicnc-nictabolietvlaklte by indi \iduc verhoog na blootstelling aim verhoogde fisieke aktiwitcit. die verhoogde sim patiesc aktiwiteit wat voorkom tydcns oefening, kan n verklariiig bied vii‘ die antideprcssicw e werking van oefening. • die algcm ccnste oorsaak van depressie is waarskui lik g c ic c in stressors wat die lewe v a n individue van dag lot (lag b cinvlocd. hier word gcdinlc aan aspek te soos die dood mui ’n naby familielid, huwclik sproblcm c, probleme by die werk, linansielc prob lcnic. verhoogde vcrantwoordclildiede en eisc wat aan ’ n persoon gcstcl word, ensovoorts. navorsing het nie alleen uiigcwys dal (lcprcssiew e persone wel aan oom iatigc strcs blootgcstcl is nie, maar ook die m oontlildieid dat stressors op (lie langc duur vcran dcringc in die inipulsgcleidlng van ecu neiuon na die volgende tot gevolg kan lie, wat dtm weer n 1 0 i in die ontstaan van g cm ocd sversteu riiig s s p e c l . d i e oiibouende rol wat oefening bv individue m et ’ n hoe stresvlak kan spcel, is deur verskeie navorsers aangedui. hoc fikser ’n persoon is, hoc goner kan die sistem c in die liggaam na uonnaal tcn igk ccr na 'n strcsvolle gebeurtenis.'"' \'erhoogdc acrobicse flk shcid het n buifereffek op die mate waartoc die lig­ gaam op strcsvolle situasies rcagccr.'" die negaticwe effek wat strcsvolle lcwens-crvarings op gcson dheid het, verniindcr as die oefeningsvlakke verhoog word.*1 die ontspannende invloed vtui oefening (weg van lw ellen d e veranuvoordelikhede), vennindering in liggamnsmassa, locnamc in qkshcid, buitelu grekreasie, sosiale intcraksic en bemccsteringsid< scs het ook ’n positiewe effek .'' • i til die psigodinaniicsc teoric blyk dit dat oefening wel n bydrae kan lewer tot die verbctering van die gcnioedstem m ing van individue deur die fasilitcring van iiisiif by n persoon van hom sclf, asook deur die ont\vild<eling v:ui self-dissipline en ’n b eg iip rail per soonlilie beperkings."’ 18'' • volgens die gedragsteoric vind verbctering vtui die geiiioedstcm ining van indi\i(lne d e m n iid dcl van oefening plaas en wel om die volgende redes: oefening het ’ n injierentc en vei'wonve versterk ingswaarde vir die individu. oefening kan die vlalt van gedragsafliaiddikc posi tiewe vcrstcrking by die individu verhoog. oefening kan die eiewaarde van ’n individu verbe tcr deur die individu se ervaring van fisieke vcrbc teilng en moontlike preslasic wat bercik kan word. die verbctering in die eiewaarde en fisieke voorvouaren 7 5 a m p o u l e s diclophenac sod iu m 7 5 m g / 3 ml w m fa m . oxoi 0, /ii 22 sports medicine november 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) kom s van die individu gee weer aiudeiding tot b e ter sosiale vaardigheid. • die kognitiewe teorie verldaar die invloed van oefen­ ing op depressie soos volg: oefening kan ’n persoon se negatiewe gedagtes oor h om self en die wereld tydelik verbreek. die bewuswording van snkses deur die bem eestering van oefenaktiwiteitc, kan lei tot selfaanvaarding.111s:’2 uit voorafgaande is dit duidelik dat ’ 11 verklaring vir die antidepressiewe werking van oefening nie voor die hand liggend is nie. tot tyd en wyl die oorsake van die depressie nie duidelik is nie, kan die terapenticse we rising nie onomwonde verldaar word nie. sa m e v a tte v g vanuit die lncla-analitiese ondersoek dui die oorkoepc lende resultate sterk op die positiewe invloed wat oefening op die verlaging van depressie het. ten opsigte van die veranderlikes ouderdom , geslag en gesondhei dstoestand is die volgende gevind: • die ouderdom skategorie kinders (jonger as 18 jaar) het die grootste verlaging in depressie getoon. • geen versko in geslag is gevind nie. • ongesonde pcrsone het beter residtate as oenkvnlik gesonde persone gelewer. oefening as behandelingsinetode het dus beslis ’n p osi­ tiewe invloed op d ie verlaging van d ep ressie. ‘ n multidissiplinere spanbenadering van kim diges oor vakdissiplinere grense heen word gevolglik bepleit ten einde 11 incer omvattende en effektiewe sti'ategie van behandeling aan depressiewe pasiente te kan voorsien. b r o n n e l y s 1. fennel mj. 1989 depression. in k hairston. pm salkovskis. j kirk cv dm clcirk ( eds. j . cognitive behaviour therapy for psychiatric problems: a practical guide. oxford: oxford university press: 169-234. 2. mart insert ew. 1990. benefits o f exercise for the treatment o f depression. sports medicine. 9 ( 6 ) : 380-389. 3. mellerowicz h & smodlaka l .y. 1981. ergometry: basics o f medical exercise testing. munich: urban & schicanenberg. 4. brown rs. ramirez de & taubjm. 1978. the prescription o f exercise for depression. the physician and sports medicine. 6(12):34-45. 5. doyneej, chambless dl& beutler le. 1983. aerobic exer­ cise as a treatment for depression in women. behavior therapy. 14 (3):434-440. 6. greist jh. 1977. run to reality. milwaukee: bulfin. 7. cueist jh. klein mh. eischens rr. fciris j. gurman a s & morgan wp. 1979. running us treatment for depression. comprehensive psychiatry. 20:41-54. s. morgan w’p, roberts ja, brand fr & feinerman ad. 1970. psychological effect o f chronic physical activity. medicine and science in si>ort. 2 4 ( 4 ) :2 13-217. 9. perri s & tempter 1)1. 1985. the effects o f an aerobic exer­ cise program on psychological variables in older adults. international journal of aging and human development, 2 0 ( 3 ) : 167-173. 10. cohen p. 1977. statistical power analysis for the behavioral sciences. (revised 3rd.) new york: academic press. 11. glass g v, mcgrair b & smith ml. 1981. meta-analysis in social research. (3rd ed.) beverly hills. california: sage publications. 12. woll fm. 1986. meta-analysis quantitative methods for research synthesis. beverly hills. california: sage publications. (serie: quantitative applications in the social sciences). 13. lolkins (11 & sime we. 1981. physical fitness training and mental health. american psychologist. 36(4)-.373-389. 14. mart insen ew. 1987. the role o f aerobic exercise in the treat­ ment o f depression. stress medicine. 3:93-100. 15. morgan wp 1969. physical fitness and emotional health: a review. american correctional therapy journal. 23:124-127. 16. ransford cp. 1982. a role o f amines in the antidepressant effect of exercise: -1 review. medicine and science in sport and exercise, 14( 1 ):1-10. 17. sachs ml. 1982. exercise and running: effects on anxiety, depression, and psychology. humanistic education and development. 21 (2):51-57. 18. taylor cb, sallis jf& needle r. 1985. the relation o f phys­ ical activity and exercise to mental health. public health reports, 1 0 0 (2 ): 195-202. 19. mcdonald dg & hodgdon ja. 1991. psychological effects of aerobic fitness training research and theory. new york: springerverlag. 20. north tc. mccullagh p & tran zi : 1990. effect o f exercise on depression. exercise and sports sciences reviews. 18■ 379-414. 21. simons aj), epstein lh. mcgowan cr. kupfer dj & robertson rj. 1985. exercise as a treatment for depression: an update. clinical psychology review. 5:553-568. 22. folk ins cit, lynch s & gardner mm. 1972, psychological fitness as a function o f physical fitness. archives o f physical medicine and rehal>ilitation. 53:503-508. 23. louw da & van jaarsveld pe. 1990. psigologiese perspek tiewe vir algemene praktisyns: gem oedsverstewinqs. geneesktinde, 3 2 (4):3-9. 24. schuyler i). 1974. the depressive spectrum. new york: jason aronson. 25. whybrow pc. aklskal hs & mckinney wt. 1984. mood dis­ orders: toward a new psychobiology. new york: plenum press. 26. ebert mh. past rm & goodwin fk. 1972. effects o f physi­ cal activity on urinary mhpg excretion in depressed patients. ixincet, 2:766. 27. post rm. kotin j, goodwin fk & gordon ek. 1973. psychomotor activity cin<l cerebrospinal fluid amine metabo­ lites in affective illness. american journal o f psuchiatru 130:67-72. 28. coleman jc. butcher jn & carson rc. 1980. abnormal psychology and modern life (6tli ed.). umdon: scott, foresmtin &. company. 29. hatfieui 31) & landers dm. 1987. psychophysiology in exercise and sport research: an overview. exercise and sport sciences reviews, 15:351-387. 30. crews dj & landers dm. 1087. a. meta-analytical review of aerobic fitness and reactivity to psychosocial stressors. medicine and science in sports and exercise. 1 9( 5) : 1114. 31. mellion mb. 1985. exercise therapy for anxiety and depres­ sion. postgraduate medicine, 77(3) , part 1:59-66. 32. weinstein ws & meyers aw. 1983. running as a treatment for depression: is it worth it? journal o f sport psychology, 5:288-301. " i—i vouanenls t a b l e t s diciophenac s o d iu m 7 5 mg y/3.1/346 o x o j 1/94 wilsinach 93062s e sports medicine november 1995 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) product news boots healthcare south africa commitment to sports medicine as manufacturers and marketers o f th e well known anti-inflammatory agents, brufen, froben and transact lvrboots has over the years developed and maintained a high profile in sports m edicine. m ore recently boots h ealthcare south africa (bhsa) reconfirm ed their continued com m itm ent to the s ci­ ence o f sports m edicine with th e announcem ent o f a r30,000 grant to the university o f cape town sports m edicine department. t h e objective o f this grant, w hich will b e paid over 3 years, is to provide funding for a num ber o f resea rch p rojects related to sports m edicine. t h ese projects are integrated into th e cur­ riculum for the two year p ost graduate sports m edicine course offered b y the uct sports m edicine depart­ ment, as such there is also an indirect benefit to stu­ dents w hich will enhance the study o f sports m edicine. t his grant also heralds boots revitalised interest in sports m edicine with th e launch o f transactm, the first ever nsaid in a patch formulation to b e intro­ duced in south africa. t h e unique features o f trans actur render it ideal for the' treatment o f a w ide range o f m usculoskeletal conditions associated with com m on sports injuries. bhsa’s involvement with sports m edicine and parti­ cularly uct sports medicine department, however, dates b a ck a fewr years and includes lw t > other com mitm ents. the b est student award for the uct postgraduate sports m edicine diplom a was introduced som e th re e / four vears ago as an incentive for students. t h is award is in th e form o f a travel grant to th e value o f r 5 000 to enable the winner to attend an international event o f own choice. in addition b oots healthcare also sponsors the annual b oots g old award in conjunction with th e south african sports m edicine association. this award, a kruger rand, is for th e b e st free paper presented at the annual sasma congress and was introduced 8 years ago. the objective being to provide recognition for out­ standing effort in the field o f sports m edicine. the 1995 b oots g old award went to dr. c jander o f the uct student health department in mowbray. bhsa remains com m itted to continued medical education and the developm ent o f h ealthcare services in south africa to m eet th e challenges that lay ahead and to ensure the b est p ossible standard o f healthcare for all th e p eople o f south africa. □ the fight against athlete’s foot ing o f non absorbent nylon socks and stockings also aid in prom oting fungal growth o f the feet. in som e instances alkaline soaps alter th e horny layer malting it m ore perm eable for th e fungi. with active participation in sports it has b een found that sportsm en and women are also very prone to fungal infections. swimming in particular creates favourable conditions, as prolonged and repeated contact with water m odifies the natural skin resistance allowing firngi to enter the layers o f skin. t h ose young men and women w ho are doing military service are highly susceptible to contracting this d is­ ease. t h e wearing o f boots, sharing o f dorm itories and com munal showers, and physical effort all assist in the contraction o f this disease. treatment o f athlete’s foot treatment o f fungi o f th e feet generally depends on the fungal species whether the 5r are local, occasionally gen­ eralised or m ixed in nature. successful results have been found following short periods o f treatment with pevaryl. pevaryl cream is sim ple to use as it is rubbed gently on the affected areas and between the toes morning and evening. t he cream contains e conazole nitrate w hich kills fungi. to com bat remaining fungi w hich may b e living in the sh oes and which may cause re-infection, it is important to apply pevaryl powder to the shoes prophylactically. to either prevent or stop a thlete’s foot it is advised that a person wears natural fibre socks, dry's well between the toes and wears open sh oes when possible. avoid d irect contact with wet floor areas in com m on ablution facilities b y wearing thongs. f o r and behalf o f r oche products ( p ty) ltd for more information p lease contact wayne vander wagen at ( o i l ) 442-3815 or 442-9561. a thlete’s foot or (m edically speaking) m ycoses o f the feet is a phenom enon that occurs uniformly throughout th e world, although it has been found that the inci­ dence o f a thletes foot m ay b e higher in the industrial­ ized countries. it is an easily treated com m on infection w hich affects mainly adult m ales and females. (h ow­ ever statistics show a slightly higher incidence in men.) what is athlete’s foot t h e definition describes it as a d isease that is caused by fungi derm atophytes, yeasts and m oulds wiiich infect th e areas between and under the toes and the soles o f feet. what athlete’s foot looks like t h e m ost com m on form starts with reddening and scal­ ing betw een the 4th and 5th toes. however, it may appear dry and scaly, m oist, or in th e form o f blisters on the undersurface o f the foot. t h e wet form is characterized by th e eruption o f small pus filled blisters which often m erge to form larg­ er blisters. after 3-4 days they are either scratched open or burst. new blisters form on th e periphery and are extremely inflamed. t h e dry form appears in the form o f isolated blisters below th e skin surface. t h ese blisters dry leaving small bare surfaces wh ich can b ecom e painful crevices. in all cases it is extremely itchy. i f not treated promptly, th e skin may tear and it could b ecom e infect­ ed with bacteria. t h is condition is difficult, to treat and m akes walking a painful exercise. the factors aiding athlete’s foot sweating is th e contributing factor towards prom oting this disease. t h e sweat provokes a break down o f the h om y layer allowing the ftmgi to penetrate into the d eeper layers o f the skin. summer heat and th e wear24 sports medicine november 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license objective sleep patterns and validity of self-reported sleep monitoring across different playing levels in rugby union c leduc,1 msc; j tee,1,2 phd; p phibbs,1,3 phd; d read,1 phd; c ramirez,1,4 md, msc; t sawczuk,1 phd; d weaving, 1,8 phd; b jones, 1,5,6,7,8 phd 1 carnegie applied rugby research (carr) centre, institute for sport, physical activity and leisure, carnegie school of sport, leeds beckett university, leeds, united kingdom 2 department of sport studies, faculty of applied sciences, durban university of technology, south africa. 3 leinster rugby, belfield, dublin, republic of ireland. 4 yorkshire carnegie rugby union football club, leeds, uk 5 england performance unit, the rugby football league, leeds, uk 6 school of science and technology, university of new england, armidale, nsw, australia. 7 division of exercise science and sports medicine, department of human biology, faculty of health sciences, the university of cape town and the sports science institute of south africa, cape town, south africa 8 leeds rhinos rugby league club, leeds, uk corresponding author: c leduc (c.leduc@leedsbeckett.ac.uk) despite the apparent importance of sleep for athletes, growing evidence highlights that elite rugby union players experience poor sleep quality and quantity.[1] the poor sleep experienced by rugby players is of concern given the potential association between low sleep quantity, recovery, injury and performance. to date, most sleep research in rugby union populations has focused on senior players, and there is a lack of research investigating sleep among adolescent players. adolescent players are an important population to investigate because they are at a sensitive stage of development. the stressrecovery balance of adolescent athletes is affected by educational (e.g. academic examinations), maturational (e.g. hormonal changes) and social (e.g. pressure to succeed, relationships and peer pressure) demands alongside their sporting requirements.[2] in addition to the unique loads and stresses that adolescent athletes are subjected to, adolescence results in a natural shift to a later chronotype (i.e. diurnal phase preferences) where (given the opportunity) adolescents tend to stay up later at night and sleep later in the morning.[3] typically, academic and training schedules do not accommodate this later chronotype which may lead to accumulated sleep debt.[4] therefore, ensuring optimal sleep habits should be a concern for all professionals working with young athletes, however, at present, normative sleep data for adolescent rugby union players is scarce. undertaking sleep research in sport is challenging. the majority of sleep research in sport has made use of either objective wristwatch actigraphy monitors or subjective selfreported questionnaires. [5,6] actigraphic methods are appealing due to their concurrence with gold standard polysomnography coupled with ease of implementation. however, actigraphy is not an option in many environments due to the cost of the devices or lack of staff with the necessary skills and time for analysis. in addition, actigraphic monitoring protocols are reliant on player compliance and do not always provide an objective measure of sleep quality. as viable alternative to actigraphy, self-reported sleep questionnaires are low cost and can provide reliable estimates of sleep duration and subjective quality over a longitudinal period. for example, caia et al.[7] showed that in professional rugby league players, information on sleep duration could be obtained by self-reported measures, but that players background: growing evidence highlights that elite rugby union players experience poor sleep quality and quantity which can be detrimental for performance. objectives: this study aimed to i) compare objective sleep measures of rugby union players between age categories over a one week period, and ii) compare self-reported measures of sleep to wristwatch actigraphy as the criterion. methods: two hundred and fifty-three nights of sleep were recorded from 38 players representing four different age groups (i.e. under 16, under 18, senior academy, elite senior) in a professional rugby union club in the united kingdom (uk). linear mixed models and magnitude-based decisions were used for analysis. results: the analysis of sleep schedules showed that u16 players went to bed and woke up later than their older counterparts (small differences). in general, players obtained seven hours of sleep per night, with trivial or unclear differences between age groups. the validity analysis highlighted a large relationship between objective and subjective sleep measures for bedtime (r = 0.56 [0.48 to 0.63]), and get up time (r = 0.70 [0.63 to 0.75]). a large standardised typical error (1.50 [1.23 to 1.88]) was observed for total sleep time. conclusion: this study highlights that differences exist in sleep schedules between rugby union players in different age categories that should be considered when planning training. additionally, self-reported measures overestimated sleep parameters. coaches should consider these results to optimise sleep habits of their players and should be careful with self-reported sleep measures. keywords: sport, training load, recovery, fatigue s afr j sports med 2020;32:1-6. doi: 10.17159/2078-516x/2020/v32i1a8456 mailto:c.leduc@leedsbeckett.ac.uk http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8456 https://orcid.org/0000-0002-7275-2928 https://orcid.org/0000-0002-8054-546x https://orcid.org/0000-0001-6367-0261 https://orcid.org/0000-0003-1605-3484 https://orcid.org/0000-0001-5929-0426 https://orcid.org/0000-0002-4348-9681 https://orcid.org/0000-0002-4274-6236 https://orcid.org/0000-0003-4243-132x original research sajsm vol. 32 no. 1 2020 2 overestimated their sleep by 20 min compared to wrist watch actigraphy. the practicality of this method could be extended if the level of agreement of other measures, such as sleep schedule (bedtime and wake-up time) and other derived sleep quality indicators were known. this information would be useful for sport science practitioners who want to monitor sleep on a daily basis with a minimum of constraint for the players, and with a good level of validity. therefore, the aims of this study were to investigate and report the habitual sleep patterns of rugby union players, and how they differ between age groups. secondly, the agreement between a sleep diary and actigraphic measurement was examined. the authors hypothesise that differences in sleep exist between playing levels in rugby union and self-reported sleep data do not reflect objective sleep measures. methods participants thirty-eight male rugby union players from a professional club in the united kingdom were recruited for the study. nine under u16 (86.1±24.0 kg, 177.9±7.1 cm, 15.7±0.5 years), eleven u18 (88.2±17.1 kg, 182.6±5.9 cm, 17.5±0.7 years), eight senior academy (sa) (94.7±13.8 kg, 184.7±9.0 cm, 19.4±0.5 years) and nine elite senior (se) (106.3±12.0kg, 186.8±10.0cm, 26.2±2.8 years) players participated in this study. participants were divided in four categories based on their current team. participants in the u16 age group were 14 to 16 years old, u18 were 16 to 18 years old, and sa players were 18 to 23 years old. all of the players older than 23 years and playing at the fulltime professional level were deemed elite senior. participants provided informed consent prior to the study. ethics approval was granted by the university’s ethics board and the recommendations of the declaration of helsinki were respected. procedure actigraphic sleep assessment was performed on a daily basis to measure sleep quality and quantity across four different age groups (i.e. u16, u18, sa and elite senior) for a duration of one week per participant, between july and september 2018. this period corresponded to academic holidays in the uk for u16, u18 and sa players, ensuring that the sleep patterns observed were self-selected and not the result of academic schedules. the training schedule for each playing group is displayed in fig. 1. additionally, participants were asked to complete a sleep diary every morning over the same period, as described by carney et al. [8] sleep assessment participants were allocated an actiwatch motionwatch 8 (cambridge neurotechnology ltd., cambridge, uk) which was worn on the non-dominant wrist. players were instructed to activate the watch by pressing a button before they attempt to sleep, and again after they wake up in the morning. a total of 253 nights were recorded. the sleep variables are presented in table 1 based on similar methodology used elsewhere (https://pubmed.ncbi.nlm.nih. gov/30789579/). table 1. definitions of each sleep variable from the wristwatch actigraphy sleep variables (units) definition bed time (hh:mm) estimated clock time at which the player attempts to sleep (press the button marker) fall asleep time (hh:mm) estimated clock time at which the player fell asleep wake time (hh:mm) estimated clock time at which the player woke up get up time (hh:mm) estimated clock time at which the player stop sleeping (press the button marker) time in bed (hh:mm) time between bed time and get up time sleep onset latency (hh:mm) time between bed time and sleep onset total sleep time (hh:mm) time spent asleep determined from sleep onset to wake up time, minus any wake time wake time after sleep onset (waso) (hh:mm) the total time spent in wake according to the epoch-by-epoch wake/sleep categorization sleep efficiency (%) percentage of total sleep time in relation to timein-bed fragmentation index (%) sum of the mobile time (%) and the immobile bouts ≤1 min fig. 1. training schedule for each playing level. for es and sa gym sessions started at 09:00 and 10:00 for a duration of 60 min while field sessions started at 14:00 and 15:00 respectively. for u18 and u16 gym and field sessions started at 18:00 and 19:00 respectively. sa and es stand for senior academy and elite senior respectively original research 3 sajsm vol. 32 no. 1 2020 sleep patterns were assessed using the consensus sleep diary proposed by carney and colleagues.[8] participants were asked to complete the diary each morning on a customised mobile application (google form, google, usa). sleep schedule, total sleep time, sleep efficiency and subjective sleep quality were the variables used. ratings were recorded in terms of subjective sleep quality using a 5-point likert scale, where one corresponds to ‘very good’ and five equals ‘very poor'. statistical analyses sleep patterns data were investigated using linear mixed models with the playing level as fixed effect and player identity as random effect. differences between age groups were then assessed with the least squares method test. all the analyses described above were performed with r studio (version 1.1.442, r foundation for statistical computing). in an attempt to assess the practical difference of playing level, further analysis was conducted using magnitude-based decisions (mbd). effect sizes and 90% confidence limits (90% cl) were quantified to indicate the practical meaningfulness of the differences in mean values.[9] effect size magnitudes were classified as trivial (<0.2), small (>0.2-0.6), moderate (>0.6-1.2), large (>1.2-2.0) and very large (>2.0-4.0). quantitative changes of greater or smaller changes in sleep parameters were assessed qualitatively as follows: <1%, almost certainly not; 1–5%, very unlikely; 5–25%, probably not; 25–75%, possibly; 75–95%, likely; 95–99.5%, very likely; >99.5%, almost certainly. regarding validity analysis, 52 nights were excluded due to the absence of diary responses. in total, 201 nights were analysed. sleep diary and actigraphy were used as criteria for sleep schedule and sleep quantity respectively. subjective sleep quality was compared with the fragmentation index and sleep efficiency. the relationship between actigraphy and sleep diary was first examined using a linear mixed model due to the non-independency and repeated measure nature of the data. the sleep schedule, as well as subjective quality validity, were assessed with the self-reported measure as fixed effect, while the sleep duration model was constructed with the wristwatch variables as the fixed effect. to assess the level of agreement, the t statistic obtained from the mixed model was then derived to an r value with 90% confidence intervals (ci). if the 90% ci overlapped positive (0.1) and negative (-0.1) trivial values, the magnitude was deemed unclear. clear correlations were interpreted as follows: trivial (0.0 to 0.1), small (>0.1 to 0.3), moderate (>0.3 to 0.5), large (>0.5 to 0.7), very large (>0.7 to 0.9) and nearly perfect (>0.9 to 0.1). further analysis was then conducted in order to obtain mean bias (90% ci), typical error of the estimate (tee and 90% ci) using a specifically designed spreadsheet.[10] the intercept, as well as the coefficient of the fixed effect, were used to provide a correction equation. results the descriptive values of sleep are presented in table 2. differences between age groups in terms of sleep schedule are shown in fig. 2. for sleep quantity, possibly to likely trivial differences were observed between elite senior and u16 (0.04 [-0.13 to 0.21]), u18 (-0.05 [-0.24 to 0.14]) and sa (0.11 [-0.22 to 0.45]) players, while other comparisons were deemed unclear. a possibly lower sleep quality was observed for sa players compared to u18 (-0.28 [0.24 to 0.14]). other results were deemed unclear. regarding the fragmentation index, likely to very likely trivial differences were observed between elite senior, u16 (0.03 [-0.11 to 0.18]) and u18 (-0.05 [-0.29 to 0.19]). a possibly trivial difference was found between u16 and sa (0.18 [-0.15 to 0.51]) for the same variable. other comparisons were deemed unclear. likely better sleep efficiency was found for sa compared with elite senior players (0.49 [0.10 to 0.88]). other comparisons with elite senior players were deemed unclear. possibly to likely worse subjective sleep quality was observed for elite senior players when compared with u16 (0.24 [0.06 to 0.42]) and sa (0.39 [-0.01 to 0.79]) players. validity analysis correlations are presented with 90% ci. the results showed a large relationship for bedtime (0.56 [0.48 to 0.63]), and get up time (0.70 [0.63 to 0.75]), with a mean bias of 50.59 min (57.09 to 44.09) and 18.38 min (-9.53 to 27.23) respectively. the correlations for time in bed (0.57 [0.49 to 0.64]) and total sleep time (0.57 [0.49 to 0.64]) also showed a large relationship. associated mean bias was 87.34 min (79.54 to 95.13) for total sleep time and 77.75 min (69.19 to 86.30) for time in bed. sleep quality indicators, such as sleep efficiency (0.07 [-0.05 to 0.18]) and the fragmentation index (0.13 [0.01 to 0.24]) showed a small relationship with self-reported sleep quality. standardised mean bias and typical errors of estimate and calibration equation are presented in table 3. table 2. sleep characteristics for the different playing level fall asleep time (hh:mm) wake up time (hh:mm) time in bed (hh:mm) total sleep time (hh:mm) wake time after sleep onset (waso) (hh:mm) fragmentation index (%) sleep efficiency (%) sleep latency (hh:mm) subjective sleep quality (au) under 16 00:28±01:13 08:28±01:30 08:16±01:46 07:07±01:46 00:53±00:25 29±9 86±5 00:14±00:17 1.91±0.81 under 18 00:11±00:59 08:28±01:07 08:38±01:14 07:22±01:05 00:55±00:28 31±10 86±7 00:18±00:31 2.41±0.84 senior academy 23:46±00:56 07:51±01:17 08:26±01:07 07:07±01:03 00:58±00:26 32±9 85±7 00:17±00:25 1.97±0.94 elite senior 23:16±00:56 07:10±00:59 08:07±00:59 07:07±00:59 00:47±00:17 31±10 88±5 00:10±00:14 2.53±0.72 data are presented as mean ± sd. original research sajsm vol. 32 no. 1 2020 4 discussion the main aims of this study were to i) compare sleep patterns between different age categories of rugby union players and ii) assess the agreement between a sleep diary and actigraphic measures. the current data showed 1) small differences in the sleep schedule between age group categories while total sleep time was consistent across age groups, and 2) the validity analysis highlighted a large typical error and mean bias between self-reported and actigraphy measures. practitioners should consider these apparent differences in sleep when scheduling training for the different age groups to avoid sleep restrictions. in addition, current study findings suggest precautions should be taken when using subjective questionnaires to report sleep measures. this study suggests differences in the sleep schedule between playing level with elite senior players, falling asleep and waking up earlier than all other age groups. caia et al.[11] found similar small to moderate differences between elite senior and junior rugby league players. it is not surprising to observe similar differences in the current study, as later sleep patterns are observed among an adolescent population.[3] sleep timing is driven by an internal circadian system, a homeostatic drive for sleep and external factors.[3] during adolescence, both internal components (circadian rhythms and homeostatic sleep pressure) change, explaining partially why u16 players slept later than their older counterparts. additionally, these results can also be explained by psychosocial factors, such as immaturity, social opportunity and independence.[10] the impact of social opportunities on sleep is corroborated by the fact that this study was performed during a holiday period for u16 and u18 players, whilst senior academy and elite senior team players were training on a daily basis. this period has been chosen because it allows for the capture of the self-selected patterns of sleep and the avoidance of the effect of the school schedule on sleep patterns. nevertheless, future studies should investigate sleep patterns when adolescent athletes have educational commitments in order to assess the effect of combined academic and training schedules. the differences in sleep schedules should be considered by coaches scheduling early training sessions. early training is common practice for athletes despite a lack of scientific evidence.[13] in support of altering training schedules, early training sessions have been found to restrict sleep and affect performance.[13] based on this study’s results, when allowed to self-select their sleep schedule, adolescent players woke up at 08:28±01:30 and as such, training should be avoided during this time. such a scheduling would enable the players to obtain sufficient sleep on a night-to-night basis. despite constraints related to congested schedules, staff should consider the time between awakening and the first training session in order to optimise sleep and performance.[14] this is the first study to analyse sleep patterns between several age categories in rugby union players. the present results showed only trivial or unclear differences in sleep quantity between age groups. on the whole, the study’s participants achieved the minimum recommended seven hours sleep per night. it should be noted, however, that numerous experts have indicated that athletes may require greater quantities of sleep in order to maintain high levels of performance.[15] young adults, and young athletes particularly, should aim to achieve nine hours of sleep per night regularly,[4] indicating that further efforts may be required to improve sleep habits in the u16 and u18 age groups. athletes can be supported in their need to accumulate fig. 2. comparison between categories regarding sleep schedule. *, possibly; **, likely; ***, very likely change/difference between categories. greys zone stands for trivial. sa and es stand for senior academy and elite senior respectively. the first playing level mentioned on the x axis designates the order of the comparison (e.g. es vs. sa: elite senior slept earlier compared to senior academy original research 5 sajsm vol. 32 no. 1 2020 additional sleep through sleep extension strategies. it has been demonstrated that when players had the opportunity to extend sleep, it was beneficial for markers of subjective recovery during a training camp.[16] as such, practitioners should consider these results in order to ensure players obtain sufficient sleep quantity. the findings from the current cohort demonstrate why it is important to monitor sleep in professional and developmental sports settings. indeed, across the observational period, 14% of the sample experienced at least one night of sleep below the recommended minimum of seven hours. while those recommendations remain debated, monitoring sleep assisted staff to be aware of these poor sleep episodes and to adjust training if necessary, and highlighting the practical usefulness of such approaches. while actigraphic measures are more accessible than polysomnography, it can still be difficult to use such devices on a daily basis, particularly within academy settings, due to human resources and the skills involved by using such devices. therefore, an agreement analysis was performed in order to assess the validity of self-reported and objective sleep measure. despite a strong relationship (0.57 [0.49 to 0.64]) observed between both measures of total sleep time, players tended to overestimate their sleep by approximately 01:30 hours, leading to large standardised typical errors. such differences might be explained by the fact that total sleep time derived from actigraphy withdraws all the awakenings period that occur during the night, suggesting wrist watch actigraphy is a more sensitive method to capture the real sleep duration among this population. another factor which could explain these results is the heterogeneity of the population age (range from 16 to 33 years old). this could also explain why trivial and small relationships with sleep efficiency and the fragmentation index were observed. such a result is not surprising as sleep quality encompasses different sleep dimensions (e.g. issues related to sleep latency, sleepiness, awakenings) which are difficult to summarise within the two objectives.[7] while similar results were found for sleep efficiency by caia et al.[7] among rugby league players, this is the first study to compare the fragmentation index and sleep quality. when assessed with actigraphy, sleep fragmentation may refer to the amount of movement or restlessness in a sleep period. such indicators may be helpful in obtaining further insights into sleep quality, which remains difficult using actigraphy. further comparisons with polysomnography are warranted to confirm the potential use of the fragmentation index as a sleep quality indicator. while practitioners should consider this inherent error when interpreting the self-reported measure, it is also important to consider the daily constraint that is characteristic to a team sports environment, particularly at the academy level. indeed, the time, cost and expertise required to collect and analyse actigraphy is an important consideration when working in a fast-paced environment like a team sports club. based on the present results, the use of actigraphy is encouraged if the actual environment is able to provide human resources fully dedicated to sleep assessment. on the other hand, the use of self-reported measures could be used but practitioners must be table 3. validity analyses between wristwatch actigraphy and the sleep diary variables means bias (90% ci) standardised means bias (90% ci) tee (90% ci) standardised tee (90% ci) coefficient of correlation (90% ci) correction equation bed time (min) 50.59 (57.09 to 44.09) 0.89 (0.78 to 1.01) moderate 46.10 (42.62 to 50.26) 1.38 (1.15 to 1.71) large 0.56 (0.48 to 0.63) y=562.90+x*0,6245 get up time (min) 18.38 (-9.53 to 27.23) -0.32 (-0.48 to -0.17) small 63.52 (58.73 to 69.25) 1.12 (0.95 to 1.35) large 0.70 (0.63 to 0.75) y=80.97+x*0.8037 time in bed (min) 77.75 (69.19 to 86.30) 1.19 (1.06 to 1.33) large 63.91 (59.08 to 69.67) 1.46 (1.20 to 1.83) large 0.57 (0.49 to 0.64) y=275.19+x*0.60463 total sleep time (min) 87.34 (79.54 to 95.13) 1.34 (1.22 to 1.46) large 54.98 (50.83 to 59.94) 1.50 (1.23 to 1.88) large 0.57 (0.49 to 0.64) y=228.19+x*0.67238 sleep efficiency (%) 3.52 (2.60 to 4.44) 0.05 (0.04 to 0.07) trivial 5.83 (5.39 to 6.35) 3.85 (2.62 to 7.10) very large 0.22 (0.11 to 0.33) y=67.47+x*0.26034 sleep quality vs sleep efficiency — — — — 0.07 (-0.05 to 0.18) — sleep quality vs fragmentation index — — — — 0.13 (0.01 to 0.24) — effect size magnitudes were classified as trivial (<0.2), small (>0.2-0.6), moderate (>0.6-1.2), large (>1.2-2.0) and very large (>2.0-4.0). tee, typical errors of estimate. original research sajsm vol. 32 no. 1 2020 6 aware of the potential bias around using such variables. correction equations provided in the current study should help practitioners to enhance the accuracy of their sleep data following self-reported measures. indeed, since short sleep duration has been shown to be related with injury risk,[4] such measures can help practitioners to optimise a player’s safety on a daily basis to align with their fast-paced environment. limitations despite the meaningful findings found in this study, a number of limitations exist. the elite senior team performed the study during in season compared to the other teams who were in preseason. secondly, subgroup analysis, considering a wider range of variables (e.g. travel, match location, match and training timing, social stressors) could be useful in order to perform validity analysis per age group but it is also necessary to understand the differences in sleep patterns. moreover, the present study was performed in a single club and the conclusions may be specific to this context. consequently, the generalisation of the present findings remains limited. finally, a potential limitation of this and other sleep studies is the absence of a specific small worthwhile change for sleep variables. future studies in this area should consider calculating such values in order to improve decision-making as well as statistical analysis. conclusion this study showed differences in sleep schedules which have to be considered when early morning sessions are performed within the adolescent categories. additionally, low sleep quality and quantity were observed without differences between categories. such results should be considered in order to avoid chronic sleep restrictions which may be of consequence regarding recovery and injury risk. consequently, it is important to monitor sleep in order to make sure that athletes obtain a sufficient amount of sleep. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. author contributions: lc; conception and design of the research, data collection, data analysis writing up the manuscript. jt; conception and design of the research, critical revision for important intellectual content; approval of the version to be published. pp; conception and design of the research, data collection, approval of the version to be published. dr; conception and design of the research, data collection, approval of the version to be published. cr; conception and design of the research, data collection, approval of the version to be published. ts; data analysis, approval of the version to be published. dw; critical revision for important intellectual content; approval of the version to be published. bj; conception and design of the research, critical revision for important intellectual content; approval of the version to be published. references 1. swinbourne r, gill n, vaile j, et al. prevalence of poor sleep quality, sleepiness and obstructive sleep apnoea risk factors in athletes. eur j sport sci 2016;16(7):850–858. 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[doi: 10.3109/07420528.2015.1118384] [pmid: 26730643] sajsm 595 (commentarty).indd short report 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license year of the face mask: do`s and don’ts during exercise dc janse van rensburg, 1, 2 md, mmed, l pillay, 1 msc (med sports medicine), mbchb, s hendricks, 3, 4 phd, bsc (hons), ja hamuy blanco,1 mbbch, da (sa) 1 section sports medicine & sport exercise medicine lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa 2 international netball federation, manchester, uk medical board member, uk 3 division of exercise science and sports medicine (essm), department of human biology, faculty of health sciences, university of cape town 4 carnegie applied rugby research (carr) centre, institute for sport, physical activity and leisure, leeds beckett university, leeds, united kingdom corresponding author: dc janse van rensburg (christa.jansevanrensburg@up.ac.za) the coronavirus disease 2019 (covid-19) is a worldwide pandemic. the lockdown levels were recently changed in south africa and the period for outdoor exercises, such as cycling and jogging, is presently from 4 am to 9 pm. exercise is currently restricted to not more than four people together. even so, people choosing to exercise still have the potential of exposure to covid-19containing droplets from those around them. while exercising, one must observe the behaviour of others in order to protect oneself, especially from those exercising nearby, to ultimately stop the spread of the virus. to safeguard the health of all, the key steps to prevent the spread of the disease include the frequent washing of hands with soap, social distancing and covering the face with a mask/buff to limit virus-laden droplets being transmitted. indeed, the government has imposed regulations about wearing masks in public spaces. guidelines from the national institute for communicable diseases (nicd) and the department of health (doh) refer to general public health with nothing specifically related to exercise. no real evidence exists for the prevention of covid-19 during exercise and most of the recommendations to date are deductions from other areas of study, specifying how these can be clinically and practically applied. discussion how do these protective behaviours impact exercise? • covid-19 disease is a highly transmissible and pathogenic viral infection caused by the severe acute respiratory syndrome coronavirus 2 (sars-cov-2). human-to-human spreading of the virus occurs when one comes into contact with an infected person, mainly via small respiratory droplets or aerosols passed on through coughing, sneezing or even exhaling. these droplets can enter the lungs via inhalation through the nose or mouth. [1] • during aerobic exercise, the rate and depth of breathing increases to ensure that more oxygen is absorbed into the blood and carbon dioxide is removed. because covid-19 penetrates the lungs via inhalation through the nose or mouth, it is necessary to be extra careful during exercise. how humans interact during activities such as running is also worth considering. using wind tunnel computer imaging, a recent simulation study by blocken et al. (2020) from the eindhoven university of technology showed that the potential aerodynamic effect of respiratory droplet transfer is greatest when running in a straight line with one person following behind another. in this case, it is the person directly behind the others who is the most exposed.[2] while this was a simulation study, the authors suggested: (1) running side by side with a two metre distance between runners; however, this is virtually impossible on public roads; (2) running at least five metres (cycling 10 metres) behind the person in front– which may become a problem if there are many people nearby; (3) running with a mask or buff on as this will reduce the droplets that are aerolised by the virus; and (4) staggered running/cycling especially when passing someone. can one run with a mask and if so, which kind of mask is best?* this is most definitely possible. selecting a face mask becomes a balancing act between maintaining comfort, breathability and concerns about infection control. • cloth face masks or ‘buffs’ made of cotton material are best. in a recent publication, greenhalgh et al. (2020) reported that using cloth face masks help to prevent droplets from being transmitted, thereby limiting community spread.[3] the mask is meant to protect the individual . even a dual layer buff will be suitable and enable one to breathe while exercising. the middle layer (in three layer masks) is often made from synthetic materials which may make masks hotter and harder to breathe through. • theoretically, moisture-wicking material will be more comfortable (i.e. more breathable), but at the cost of less effective containment of droplets due to the tiny spaces in the fabric that allow moisture removal. moisture -wicking depends on capillary action, namely the movement of a liquid (in this case, exhaled breath) through the small spaces within the fabric. the job of the moisture -wicking fabric is to rapidly move ’liquid’ to the outer surface of the fabric and to dry quickly to prevent saturation of the fabric. most moisture-wicking fabrics are synthetic, e.g. polyester and nylon. • it is preferable to use a cloth mask with a maximum of two layers. if the seal is too tight around the sides of the face there will be less movement of air. the covid-19 pandemic causes widespread anxiety and uncertainty regarding disease transmission. in many countries people are obliged to wear a face mask in public spaces. individuals involved in sports participation at any level need to make informed decisions on wearing a face mask during exercise. currently there is no scientific evidence on what to advise regarding the safety of wearing a face mask during exercise, or what type of mask to use. this short report aims to answer these questions in a structured and practical way. keywords: covid-19, masks, exercise, physical activity, corona virus, prevention, health s afr j sports med 2020; 32:1-2. doi: 10.17159/2078-516x/2020/v32i1a8615 mailto:christa.jansevanrensburg@up.ac.za http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8615 https://orcid.org/0000-0002-8353-3376 https://orcid.org/0000-0003-1058-6992 https://orcid.org/0000-0002-3416-6266 https://orcid.org/0000-0002-8035-1438 short report sajsm vol. 32 no. 1 2020 2 • as previously mentioned, buffs are usually made from synthetic, lightweight material designed to reduce heat build-up. they are also open at the bottom, allowing for better air flow. this can be good from a comfort point of view, but is perhaps less effective for infection control. • vented masks, if fitted correctly, have a one-way valve that protects the wearer by allowing for easier exhalation, the reduction of the build-up of carbon dioxide, and the prevention of humidity. the problem is that it only filters inhaled breath and not exhaled breath. although a vented mask is more comfortable for the wearer, it, unfortunately, does not contain the droplets. • there is a worldwide shortage of personal protective equipment for healthcare workers and others on the frontline. respirator masks such as the ffp1, ffp2 and n95 should be reserved for that purpose, and for use in the other specific working environments that require them. the general public should be using cloth face masks. *specific to south african regulations: rsa recommended guidelines: fabric face masks manufactured by south africa’s clothing and textile manufacturing industry for general public use. 9 april 2020 https://www.nicd.ac.za/wpcontent/uploads/2020/04/rsa_recommended-guidelines-formasks_summary_final09.04.2020_for_distribution.pdf taking care of the cloth mask • wash the mask regularly with soap and water. • dry the mask thoroughly and then preferably iron it. is it dangerous to exercise with a cloth mask? • if a mask is not cleaned regularly, it may be contaminated with the novel coronavirus and also other viruses or bacteria. always have an extra mask at hand while the other is being washed and dried. • proper handling of the mask is vital. never touch the exposed front of the mask as this is where the highest concentration of potential viruses and bacteria can be found. • a mask must be breathable. this is subject to the thickness of the material and the tightness of the seal on the face. a mask theoretically increases the breathing effort and causes an accumulation of co2. • the more breathable the material, the less likely it is for co2 to accumulate. when running it is necessary to breathe in oxygen and breathe out carbon dioxide without carbon dioxide accumulating, which could cause fainting. • cloth masks or buffs are likely to get wet during exercise, due to the accumulation of moisture from exhaled breath. breathing through damp cloth is more strenuous. this can be more of an issue in hot and humid conditions, so anticipate this and act accordingly. consider taking a second mask/buff during an exercise session to change into once the original one is saturated with moisture. however, this can also be tricky as one should try to touch one’s face as little as possible • if medical conditions exist, such as obstructive lung disease, bullous lung disease, other lung diseases or heart diseases, it will be best to get a doctor's opinion before running with a mask as this may worsen any medical condition.[4-6] is it possible to exercise at any intensity with a cloth mask? it will be possible to exercise easily with a mask while doing low-intensity exercise. however, with moderate/high-intensity exercise, it may become difficult to exercise with a mask and could pose dangers as mentioned above. exercising at moderate or high intensities, may bring on the abovementioned medical risks. if the intention is to exercise at these intensities, it should be done outside at home and not wearing a mask. however, this will require specific clearance from the government at level 3 of the risk-adjusted approach of lockdown. important reminders  there is unfortunately an inverse relationship between protection and breathability with regards to the wearing of masks while exercising.  it is important not to exercise at all when feeling ill. consult with a doctor, get treated accordingly, and obtain their medical permission to exercise. if attempting to exercise with ’flu’ symptoms, there is a potential that this viral infection may affect the heart, causing myocarditis (infection/inflammation of the heart muscle) that may lead to sudden cardiac death. since the novel coronavirus is new, not much is understood about it yet and it must be assumed that the same problems can occur as when exercising with ‘flu’. conflicts of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. references 1. shereen ma, khan s, kazmi a, et al. covid-19 infection: origin, transmission, and characteristics of human coronaviruses. j adv res. 2020; 24: 91-98. doi: [doi; 10.1016/j.jare.2020.03.005] 2. blocken b, malizia f, van druenen t, et al. towards aerodynamically equivalent covid-19 1.5 m social distancing for walking and running. 2020: 12p. [http://www.urbanphysics.net/covid19.html] 3. greenhalgh t, schmid mb, czypionka t, et al. face masks for the public during the covid-19 crisis. bmj 2020; 369:m1435. [doi: 10.1136/bmj.m1435] [pmid: 32273267] 4. person e, lemercier c, royer a, et al. effect of a surgical mask on six minute walking distance (article in french). rev mal respir 2018; 35(3):264-268. [doi: 10.1016/j.rmr.2017.01.010] [pmid: 29395560] 5. motoyama yl, joel gb, pereira pe, et al. airflow-restricting mask reduces acute performance in resistance exercise. sports(basel) 2016; 4(4):46. [doi: 10.3390/sports4040046][pmid: 29910294] 6. andre tl, gann jj, hwang ps, et al. restrictive breathing mask reduces repetitions to failure during a session of lower-body resistance exercise. j strength cond res 2018; 32(8):2103-2108. [doi: 10.1519/jsc.0000000000002648] [pmid: 29847532] further reading https://blogs.bmj.com/bjsm/2020/06/12/should-people-wear-a-face-maskduring-exercise-what-should-clinicians-advise/ https://www.nicd.ac.za/wp-content/uploads/2020/04/rsa_recommended-guidelines-for-masks_summary_final09.04.2020_for_distribution.pdf https://www.nicd.ac.za/wp-content/uploads/2020/04/rsa_recommended-guidelines-for-masks_summary_final09.04.2020_for_distribution.pdf https://www.nicd.ac.za/wp-content/uploads/2020/04/rsa_recommended-guidelines-for-masks_summary_final09.04.2020_for_distribution.pdf http://www.urbanphysics.net/covid19.html https://blogs.bmj.com/bjsm/2020/06/12/should-people-wear-a-face-mask-during-exercise-what-should-clinicians-advise/ https://blogs.bmj.com/bjsm/2020/06/12/should-people-wear-a-face-mask-during-exercise-what-should-clinicians-advise/ south a f r ic a n jo u r n a l of sports medicine sportgeneeskunde jo u r n a l of t h e s.a. sports m e d icin e association t y d s k r if van die s.a. sportgeneeskunde-vereniging n a tio n a l a dvisory b o ard e d ito r in c hief: --------- v o l u m e 7________ n u m b er 4 s e p t /o c t 1992 clive noble a ssociate e d ito rs: p ro f td noakes dawie van velden a dvisory b o ard : traumatology: etienne hugo physiotherapy: joyce morton nutrition: mieke faber biokinetics: martin schwellnuss epidemiology: derek yach radiology: alan scher pharmacology: john straughan physical education: hannes botha internal medicine: francois relief in te rn a tio n a l a dvisory b o ard lyle j micheli associate clinical professor of orthopaedic surgery boston, usa chester r kyle research director, sports equipment research associates california, usa p rof hc wildor hollmann prasident des deutschen sportarztebundes koln, west germany howard j green professor, department of kinesiology ontario, canada george a brooks professor, department of physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke associate professor, biology department, university of colorado colorado, usa graham n smith physiologist glasgow, scotland contents r e p o rt fro m th e e d ito r olympic games barcelona 1992: medical report and recom m endations.............................. 2 soft tissue in ju ries diagnosis and treatment o f long head o f biceps tendinitis in sportsmen a goldberg and ca s m i th ...................................................................... 6 hockey hockey injuries in high school first team schoolgirl players o f the southern transvaal and griqualand west m petrick, kf laubscher, em peters ....................................... 9 phy sio th erap y comrades marathon 1992 j m o r to n ............. 17 c rick et cricket injuries o f the south african team at the world cup and in the caribbean: the physiotherapy perspective craig smith ........ 20 jo u r n a l o f t h e so uth a frica n sports m e d ic in e associa tion 2 6 9 w e s t a v e n u e h e n n o p s m e r e v e r w o e r d b u r g , 0 1 5 7 photographs counesry o f the image bank t h e j o u rn a l o f the s a s p o rts m e d ic in e a s s o c ia lio n is p u b lis h e d b y m e d p h a r m p u b lic a tio n s , 3 rd f lo o r n o o d h u lp lig a c e n tre , 2 0 4 b h f v e rw o e r d d riv e , r a n d b u r g 2 1 9 4 . p o b o x 1 0 0 4 , c ra m e r v i e w 2 0 6 0 . t e l: (0 1 1 ) 7 8 7 4 9 8 1 /9 . t h e v ie w s e x p re s s e d in th is p u b lic a tio n a re th o s e o f t h e a u th o rs a n d n o t n e c e s s a rily th o s e o f th e p u b lis h e rs . primed by t he natal witness priming and publishing company (ply) lid r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) report from the editor olympic games barcelona 1992 medical report and recommendations clive n oble introduction i was appointed to be team doctor by the president o f nocsa, m r sam ramsamy on 24 june 1992, 26 days before departure to the olympic games. recommendations the c h ie f team d octor should be appointed a t the end o f the previous olympic games. it would be preferable f o r this doctor to have attended the previous olympic games as he would have a better understanding o f the structure and requirements o f the olympic m edical team. the doctor should also become a member o f the international olympic medical officers and attend their meetings. h e/she should aim f o r closer liaison with the african group o f olympic m edical offi­ cers. h e/she should become a m ember o f the d oping control committee o f nocsa and attend international meetings to increase knowledge. the c h ief team d octor should help in the selection o f the rest o f the m edical team. i was the only doctor appointed and no physio­ therapist or masseurs were to accompany the team. the io c is apparently going to prescribe m inim al standards on the size o f the medical team. in consultation with the canadian m edical team they advised that it was better to take physiotherapists who can do massage rather than pure masseurs. the president had arranged for the australian physiotherapists to help with any injuries which may occur; they were adjacent to the s a team in the olympic village. i f the team is large enough, team doctors and physios should accompany the larger teams, e.g. soccer and athletics to their training and competition venues. a doctor/ physiotherapist should accompany any team which lives away fro m the olympic village. i f possible, a doctor should accompany the team f o r the more violent sports boxing and wrestling. the reason for this small medical team was due to the fact that the late entrance o f the team to the games had restricted the number o f persons involved in the olympic village and the presi­ dent had, in my opinion, correctly decided to send more competitors than officials. the team consisted o f approximately 96 athletes and 24 officials. there were also 25 disadvan­ taged black sportsmen and officials who had fx accreditation and lived ± 100 km from barce­ lona. they had the use o f the olympic village but could not sleep in the village. there were approximately 25% black and coloured com­ petitors in the team. in order to increase the size and quality o f sports medicine vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) report from the editor the team, a massive restructuring programme o f sport in south africa is needed. it is important to increase the num ber o f disadvantaged sportsmen in the team . to do this it is essential initially to work at the strengths o f these athletes. therefore, sports such as athletics, soccer and boxing should be given priority. adequate fa cilities are essential, e.g. olympic tracks, gymnasiums and soccer fie ld s in all m ajor black areas. coaches should be imported with the aim o f teaching our coaches but also helping to polish our distinguished athletes. more use o f sports science is essential. i was invited to participate in an investigative panel to assess the factors in cheryl roberts' stimulant drug taking case. two major factors emerged: (a) the test was incorrectly done in that the question regarding the taking o f medication had not been asked and (b) the form was incor­ rectly planned. an anti-doping committee should be re­ sponsible f o r educating both athletes and officials. it should also be responsible f o r a program m e o f random and routine testing to be carried out on all top athletes. the fo rm s and methods o f testing should be standardised and be brought up to inter­ national standards. p r e -g a m e a ssessm e n t one week before departure, the team assembled at the jan smuts sun hotel. h ere they were tested for banned substances. although the respective sports organisations were informed in m ay by means o f an ioc circular concerning banned substances, a number o f the olympic competitors had taken banned substances. a ll athletes should be tested f o r drugs before departure as was done. they should be knowledgable as regards doping before­ hand. they were also forbidden from swimming in the sea because o f pollution and the danger o f gastro-intestinal infection. a f u l l investigation m ust be done into the site o f the next olympics, i.e. atlanta, as re­ gards temperature, humidity, altitude and any other fa cto rs that could affect the ath­ letes. this should be done as soon as possible so that training program m es can be m odified to improve performance, e.g. the marathon runners trained in the wrong conditions f o r barcelona. a large p art o f their training should have been done in barcelona or i f this was not possible running on a treadmill in correctly heated rooms with high humidity to improve acclimatisa­ tion. the athletes were apparently tested prior to this at the university o f pretoria. these tests were for physical fitness. sports scientists should p la y a fundam ental role in preparing the team f o r olympic competition. careful monitoring o f the team is essential. coaches should be taught m ore about the scientific assessment o f f i t ­ ness and should liaise closely with sports scientists. the team left on 20 july on a direct night flight from johannesburg. the team travelled in economy class. d ay time flg ith s i f possible would be helpful to the athletes. an extra p erio d o f time should be made available f o r "jet la g ". for long flig h ts, e.g. atlanta, 1 would recommend the use o f "sleeping p ills " f o r those who request them i f there is a night flight. the team arrived 5 'h days before the opening ceremony. a period o f acclimatisation and adaptation, as was done in barcelona, is recommended. the team was advised that in barcelona they o l y m p ic a l v il l a g e were not to drink tap water, even to clean their teeth with tap water, because o f the danger o f in the olympic village, there was an abundance infection. o f food'and water obtainable 24 hours a day. -----------=--------------------------------------------------------------------- 3 sportgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) report from the editor soft drinks were also readily available. weight control, e.g. daily weighing is rec­ om m ended with suitable dietary restrictions in cases o f weight alteration. a thorough knowledge o f diet control and correct eating by a dietician is fu n d a ­ m ental to all coaches. this should be done through the individual unions but should be m onitored by nocsa to assess that all sports associations comply. until competitions began, training continued at venues in and around barcelona. i f at all possible team and individual coaches should be given adequate accreditation in order to allow them to accompany the p a r­ ticipants to all venues and to the olympic village. these coaches should have (a) knowledge o f dietetics and (b) knowledge o f massage. one o f the teams rowing was not living in the olympic village and had no organised medical cover. teams not living in the village should have their own m edical team with them. barcelona in july/a ugust has a high temperature and high humidity. a f u l l investigation must be done into the site o f the next olympics, as discussed previ­ ously. medical a num ber o f athletes arrived at the olympical village with upper respiratory tract infections. even on the plane, 3 competitors had to be treated for 'flu and two for nausea and vomit ting. the basic medical requirements o f a team o f a sim ilar size should be a minimum o f 3 doctors: * a sports medicine specialist; • two general practitioners with sports medicine background; 4 ■ ■ -̂--------sports medicine vol. 7 no. 4 • three physiotherapists who would also do massage. sixty two cases were treated in the 3 weeks i was with the team 32 with injuries and 30 with illness. seven cases were from the disad­ vantaged team and 6 cases were officials. adequate medication to cover all m ajor and minor medical problems is necessary. equip­ m ent to handle medical emergencies, e.g. heart attacks, should also be available. only one case o f illness (l udw ig's angina) from one o f the disadvantaged group required admission to hospital. the doctors m ust immediately assess the medical fa cilities available at the olympic village and sports venues. nine cases were referred to the australians for physiotherapy. unfortunately massage was not available from the australians as their masseurs were already overburdened with work. i therefore took over the role o f masseur and did 11 cases. the athletics teams brought in an american chiro­ practor who did approximately 8 cases, most o f them from the athletics team. the massage was not for medical treatment, but for the feeling o f general well-being that it gives. the swimming coach also gave massage to the swimmers. see recommendations f o r the basic medical requirements o f a team o f a sim ilar size, as discussed previously. medical committees i attended: • the general meeting o f team doctors at the olympic village. this consisted o f an instruc­ tional talk covering all aspects o f medical treatment and drug testing at the olympic games. it is important that all m edical personnel attend all m edical meetings at the time o f the olympic games. this helps to keep abreast r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) report from the editor o f the latest developments. • an instructional tour o f the polyclinic in the village as regards all its facilities. polyclinic and drug testing tours are essential. • a tour o f the drug testing facility in barcelona. • a meeting o f the international olympic medical officers association, under the secre tary-generalship o f m ike iraqui o f the united king­ dom. i was granted mem ber­ ship to this organisation whose aim is to increase knowledge o f olympic sports medicine. membership o f the iomoa is important. • a meeting o f the african olympic team doctors under the chairmanship o f prof. constant roux from the ivory coast. • a number o f meetings with the australian and canadian medical groups concerning the size and structure o f fu­ ture medical teams from south africa. closer liaison with the a f­ rican m edical group is es­ sential in order to increase contact with our african colleagues. d r clive noble, mbbchb fcs (sa) editor-in-chief subscription to sports medicine dear doctor, the characteristic that distinguishes a professional from an educated person is the professional person's desire and responsibility to stay abreast o f the development o f his or her field o f expertise. the halflife o f our professional knowledge is about 3 years, and for this reason it is vitally important to continuously refresh and supplement our knowledge. sports m edicine, the official mouthpiece o f the sa sports medicine association, has over the years become a treasured source o f knowledge for the health care profes­ sional in the sports medicine arena. the journal features not only original research papers and articles by leading special­ ists in sports medicine, but also current news and relevant abstracts. your subscription to sports m edicine is an investment in your future o f the health care profession. we count on your continued support. name: address: code: tel: enclosed please find my cheque/postal order payable to sasma for: • r75 for full m em bership to sasma (this includes receiving sports m edicine free o f charge). • r75 for associate m em bership to sasma (this includes receiving sports m edicine free o f charge). • r50 for student m em bership to sasma (this includes receiving sports m edicine free o f charge). • r27,50 + vat (r30,25) for subscription to sports medicine. j i___________________________________________________________________ i sportgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) soft tissue injuries diagnosis and treatment of long head of biceps tendinitis in sportsmen a goldberg and c a smith key words: soft tissue injury, long head o f biceps tendinitis, deep transverse frictio n s, rehabilitation programme. abstract soft tissue injuries o f the shoulder jo in t in sportsmen are common. a condition that seems to be infrequently diagnosed by medical practitioners (yet well recognised by physiotherapists) is that o f long head o f biceps tendinitis. the signs knd symptoms for this extremely common condition are presented. treatm ent is by deep transverse frictions (dtf) and response to treatm ent is uniform ly good. introduction soft tissue injuries o f the shoulder jo in t are common among both the sporting and non-sporting public. such in­ juries in sportsmen are usually due to an overuse nature as in a goldberg, bsc (physiotherapy). post graduate student, department o f anatomy and cell biology, uct. ca smith, bsc (physiotherapy), bsc (hons) sports science. uct sports injuries clinic. "throwers shoulder" o r "swim­ mers shoulder" but may also be due to sudden exertional force as in weight-lifting. the main soft tissue inju­ ries o f the shoulder affecting the sportsman are collectively grouped and generally known as the "rotator cuff impinge­ ment syndrome". this refers to a number o f clinical entities, the most common o f which is supraspinatus tendinitis, but also includes infraspinatus and subscapularis tendinitis. the well known "painful arc" sign is normally present (pain is experienced between 70 and 120 degrees when the arm is actively abducted') and the impingement sign may also be positive (passive flexion o f the arm to 90 degrees and then medial rotation o f the shoulder p ro d u c e s th e sy m p to m s). continued impingement may lead to degeneration o f the rotator cuff tendons and pos­ sible rupture o f the cuff. h ow ever, injury to the shoulder is not only confined to the above structures but also commonly involves the long head o f biceps tendon. this structure is a common source o f shoulder pain in sportsmen, yet is often overlooked by clinicians. the reason for this is that the signs and symptoms associated with this lesion of­ ten match those o f rotator cuff injuries, and it has thus become fashionable to lump such inju­ ries under this diagnosis. this brief paper thus dis­ cusses the clinical condition o f long head o f biceps tendinitis with the intent o f bringing it to 6 --------------------------------------------------------------------------sports medicine vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) soft tissue injuries the attention o f diagnostic cli­ nicians. anatomy the long head o f biceps tendon attaches superiorly to the su praglenoid tubercle o f the scapula and lies within the cupsule o f the shoulder joint. it glides over the head o f the humerus and leaves the jo in t in the bicipital groove which is bordered by the greater and lesser tuberosities at the proxim al end o f the humerus. above the humeral head, the c o r a c o a c r o m ia l lig a m e n t forms an arch over the shoulder jo in t to joining the coracoid and acromion processes to each other. underneath the acromion lies the sub-acromial bursa which lies over the supra spinatus tendon and the intra articular portion o f the long head o f biceps tendon. with abduction, elevation and exter­ nal rotation o f the arm , im ­ pingement o f these structures may occur. signs and symptoms long head o f biceps tendinitis is known to occur in baseball pitchers, canoeists, swimmers, weight-lifters, javelin-throw ers, golfers, volleyball and ten­ nis players and is thus recogni­ sed as the most common cause of anterior shoulder pain.2 even so, this condition is seldom diagnosed by medical practi­ tioners when referring these patients for physiotherapy. the traditional diagnoses in­ clude impingement syndrome, painful arc syndrome and rota­ tor cu ff tendinitis which are uninform ative and non-specific regarding the injured structure. the reason for infrequent diagnoses o f this condition is unclear as it is well recognised by physiotherapists. the con­ dition may occur on its own or simultaneously with a supras pinatus lesion, and thus pres­ ents with signs o f a painful arc and impingement syndrome. biceps tendinitis may either present in the acute or chronic form. the acute patient nor­ mally complains o f pain in the shoulder caused by a specific action, such as baseball pitching o r spiking in volleyball, and may also have associated weakness when attempting to play. the patient with the chronic form may have the symptoms for some months, only seeking treatment when his pain becomes severe enough to limit his playing. the injury is often worse in the beginning o f the season becoming easier as the season progresses yet still remaining a chronic, nag­ ging ache whenever the patient plays. several tests are available to the clinician to confirm the diagnosis. the most common ones are as follows: ^ yergason’s test the affected arm is held with the elbow flexed at 90 degrees and against the chest. the patient is then told to rotate the arm out­ wards, bend the elbow and supinate the forearm while the exam iner resists these movements at the elbow and forearm. downward traction must also be ap­ plied to the elbow. the exam iner palpates the bi­ ceps tendon in the bicipital groove in order to detect subluxation o f the tendon. pain is reproduced by either subluxation o f the tendon o r due to the tendinitis injury itself. it must be stressed that y ergason’s test is prim ar­ ily used to detect insta­ bility o f the tendon in the bicipital g ro o v e.1 j impingement sign ^ the well documented im­ pingement sign may be present if either the supra spinatus or biceps tendons are being pinched under the coraco-acrom ial arch during active flexion. pain localised to the area o f the coraco-acrom ial arch is indicative o f impingement.1 in order to differentiate the tw o, the patient with biceps tendinitis will dem­ onstrate tenderness over the bicipital groove with palpation. 1 resisted test resisting elbow flexion may produce pain, but in order to clarify the affected structure, pain with resis­ ted supination o f the pronated forearm with the elbow flexed to 90 degrees would positively indicate biceps tendinitis. crepitus may be felt if there is tenosynovitis o f the tendon in the groove. i f the above tests are negative, one should not rule out the diagnosis. in chronic cases, palpation may be the only posi­ tive sign which can be elicited. tenderness should be sought along the length o f the tendon -------------------------------------------------------------------------------— 7 sportsgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) soft tissue injuries from the bicipital groove to the proxim al portion o f the muscle. the m id-part o f the tendon is usually at fault.3 t r e a t m e n t treatm ent o f biceps tendinitis is by way o f d tf o f twenty minutes duration on alternative days3 or 5 to 10 minutes dura­ tion on consecutive days. the bicipital groove is easily pal­ pated with the arm in some degree o f external rotation.4 this is also the position recom mbnded for perform ing d tf. the d tf act by breaking down the adhesions within the ten­ don and its sheath similarly as it does for muscle injuries.5 other physiotherapeutic mo­ dalities which can be used in­ clude ultrasound and laser therapy. steroid infiltration is not required as full recovery is to be expected if the correct site(s) is treated effectively with frictions. usually three to four sessions suffice although chronic cases may require up to eight treatments until complete recovery is achieved. a rehabilitation program m e in v o lv in g stre tch in g and strengthening must also be in­ corporated once the acute phase is over. stretching the tendon must be done before and after exercise with the arm in 90 degrees o f shoulder abduction and external rotation, with the forearm pronated and the el­ bow extended. the shoulder is then extended and slightly more o r less abduction can be applied to get the best stretch. the patient can also be taught to stretch the tendon by holding the arm out in this position but having the hand and wrist sup­ ported against a wall or door frame. the body is then used to apply further stretch to the ten­ don. the double handed method with the uninjured arm used to help stretch the tendon in extension behind the back is also useful. the patient must then be given resisted exercises to strengthen the muscle and tendon, especially in the posi­ tion which stresses the tendon most, i.e. full shoulder eleva­ tion for volleyball players and abduction, external rotation and extension for baseball pitchers. these activities need to be slowly retrained in order to completely rehabilitate the patient. c o n c l u s io n tendinitis o f the long head o f biceps is a common cause of shoulder pain yet is infrequently diagnosed by referring medical practitioners. the signs o f pathology are a positive yer­ gason’s test while a positive impingement sign with tender­ ness localised over the bicipital groove provide extra confirm a­ tion o f the diagnosis. treat­ ment is normally by way o f dtf applied to the affected area. recovery is good in most, if not all cases. c a se r e p o r t a young male, aged 23 years and a keen sportsman, repor­ ted for treatment for his right shoulder which he injured while playing baseball. a recurring injury which had troubled him at the beginning o f the previous two seasons, it hurt him most when he pitched the ball. when he presented for treatment, the pain had been present for two weeks and had progressed to the point where he could no longer pitch the ball without severe shoulder pain. he had recently begun a weights pro­ gram m e and felt that this could also have contributed towards the injury. on examination o f his shoulder, he had full range o f active and passive movements, the pain only being elicited at the end o f range o f lateral rota­ tion and elevation through abduction. he experienced dif­ fuse release pain in the shoul­ der when resisting abduction in the neutral position. all other resisted tests were pain free. palpation o f the should did not produce a specific site o f pain although there was some ten­ derness in the region o f the long head o f biceps tendon. the differential diagnoses con­ sidered w ere sub-acrom ial bursitis and biceps tendinitis. h e was initially treated for the bursitis for two sessions with laser, ultrasound, inter­ ferential and m obilisation therapy, which had little last­ ing effect as he still had pain when pitching the ball. reas­ sessing the shoulder, it was decided to treat the biceps ten­ don as this reproduced the pain most clearly with palpation and had since become painful when resisting elbow flexion. the treatm ent was thus changed to d tf o f the tendon in the bicipi­ tal groove with ultrasound and laser therapy. following a fur­ ther two sessions he could p itc h p a in f r e e and w as summarily discharged from treatment. references on request. 8 ---------------------------------------------------------------------------sports medicine vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) hockey hockey injuries in high school first team schoolgirl players of the southern transvaal and griqualand west m petrick, kf laubscher, em peters i key words: running head, hockey injury in high school first team players. ! abstract ;. questionnaires were sent to the first team players and coaches of the seven best hockey schools | in the griqualand west and southern transvaal regions during the 1990 south african | schools hockey season. fifty percent of the players (n = 157) had sustained injuries as a re | suit of hockey during their hockey careers. the most prevalent injuries were ankle injuries ; (27%), knee injuries (15%) and lower leg overuse injuries (8,5%). i f : of all the injuries sustained during their hockey careers, in southern transvaal knee inju i ries were the most common (19,6%), followed by ankle injuries (17,9%) and injuries to the face and head (8,9%). ankle injuries were the most common in griqualand west (33,3%), followed by overuse injuries of the lower leg (12%) and knee (10,7%) and thigh muscle (8%) injuries. although the coaches were well-trained and took precautions attempting to prevent the ! development of overuse injuries in their players, a discrepancy existed between the injuries ; reported by the coaches and players. the coaches report a much lower incidence of injuries i amongst their players in the 1990 season than the players do. i m petrick, bsc (physiotherapy). department o f physiotherapy, university o f the witwatersrand, johannesburg. kf laubscher, bsc (physiother­ apy)division o f physical education, university o f the witwatersrand, johannesburg. em peters, msc (med). division o f physical education, university o f the witwatersrand, johannesburg. introduction in a study reported by van heerden (1 9 9 1)1 an injury rate o f 4,8% was found amongst prim ary school girl hockey players during a two week hockey competition. four of the five recorded injuries oc­ curred due to high velocity impact, while one player sus­ tained a calf muscle tear. however, little is available on common hockey injuries am on­ gst adolescent and adult hockey players. in a preliminary study undertaken by klemp and jordaan (1989)2 it was found that shin splints was highly preva­ lent among a select group of high school hockey players. this prompted the authors to undertake a broader survey of the incidence o f hockey inju­ ries am ongst female hockey players in south africa. the objective o f this study therefore was to obtain a pre­ liminary profile o f injuries which are prevalent in first team female hockey players at high school hockey level in the southern transvaal and g ri­ qualand w est regions. ---------------------------------------------------------------------------------- 9 sportgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) hockey t able 1: players' problems with feet, knees, back, legs and hips pr o bl e m a rea d esc r ipt io n in cidenc e n* % feet flat feet painful feel, foot cram ps, plantar 11 7 fasciitis, callouses, blisters 13 9 total 24 16 k nees painful knee 13 9 w eak knee 3 2 o ther 5 3 total 21 14 b ack l ow back pain 9 6 t orn back m uscles/back injury 3 2 o ther 6 4 total 18 12 l eg s shin splints/com partm ent syndrom e 5 3 w eak/injured ankles 3 2 t ight ham strings 16 10 m uscle soreness after playing 5 3 total 29 18 h ip painful/clicking hip 2 1 total 2 1 * n = n u m b er o f players method questionnaires were sent to the first team hockey players o f the top seven schools o f both gri qualand w est and southern transvaal schools’ hockey league (n = 157). the ques­ tionnaires sought information on aspects such as a history o f orthopaedic problems, involve­ ment in other sports, hockey training (including training methods, playing surfaces, shoe wear) and a hockey injury pro­ file. the coaches o f each o f the teams (n = 12) also received a questionnaire requesting details regarding their coaching tech­ niques or programmes and were asked to keep an attendance register o f their players for both practices and matches. they were also asked to record any hockey injuries their players sustained during the 1990 hockey season. all question­ naires were completed during august and september 1990. statistical analysis f o r discrete variables, groups were compared using the chi square test to analyse contin­ gency tables where the samples sizes and expected frequencies were adequate. w here sample sizes and expected frequencies were too small, f ish er’s exact test was employed in the case o f 2 x 2 tables. for continuous variables, groups were compared using either student’s t-test, taking into account whether the vari­ ances o f the groups were equal or not. w here appropriate, the m ann-w hitney test was used. in all cases, the level o f confi­ dence was set at 0,05. results players seventy five southern transvaal and 81 griqualand w est first team hockey players completed the players’ questionnaire. the mean age was 16 ( + 1,06) years. these players were healthy, active individuals, most o f whom (93%) participated in other sports apart from hockey. their level o f hockey partici­ pation was high, with 45% playing at a provincial level and 40% playing club hockey. the players had been mem­ bers o f the first school hockey team for a mean duration o f 1,8 ( ± 1,08) years. details o f problems the pla­ yers experienced with their feet, knees, backs, legs and hips are given in table 1. from this it is apparent that tight hamstrings, painful knees and feet were the most commonly found ailments. the players participated in a total o f 22 different types o f sport apart from hockey. o f the sum m er sports, swimming was the most popular (27%). tennis was the next popular (16,6% ), followed by jogging (10,6% ), squash (10,6% ) and athletics (10,6% ). o f the win­ ter sports, jogging was the most popular (18% ), followed by tennis (15,5% ) and squash (12,9% ). the majority o f players 10 ------------------------------------------------------------------------------sports medicine vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) hookey table 2: activities included in a hockey practice a ctivity % p la y e rs d u ra tio n (m inutes) sprinting 82 5 jogg ing 92 10 a com bination o f sprinting and jo g g in g 97 15 s tickw ork 97 20 d ribbling 96 15 s tretching 97 before training 10 after training 5 o th e r a ctiv ities m e n tio n e d by p la y e rs h ockey techniques 29 15 p ractice matches 27 15 g am e tactics 21 15 g oal shooting 15 10 table 3: club and indoor participation in the southern transvaal (n = 75) and griqualand west (n = 82) % p la y in g c lu b hockey % p la y in g in d o o r hockey at school at a club st sw st gw st gw 47,3 31,7 67,6 46,2 19,7 36 st = southern t ran sv aal gw = g riqualand w est (62%) played hockey more than three times a week and a typical practice session was considered to be longer than 60 minutes by 73% o f the sample while 82 % o f the players con­ sidered a typical match to be 30 minutes or less each way. ac­ tivities included in a hockey practice and the mean time spent on each are listed in table 2. all the respondents reported warming up before a hockey match and acknowledged the necessity of a warm up. the pre-season fitness level appeared not to matter greatly to the players, as 11 % reported never getting fit before a season, 56% sometimes getting fit and only 33% always getting fit before the hockey season started. the mean time spent w ar­ ming up before a match was 20 minutes. this included stretch­ ing (36,5 % o f players mention­ ing this), followed by hockey techniques involving stickwork (26,6% ). jogging was men­ tioned by 23,6% o f the players, while 11,9% mentioned sprint­ ing o r a jog-sprint combination as part o f the warm-up. the shoes most frequently worn for playing hockey were hockey boots (85% ). other shoes worn included "tackies" (6 %), j ogging shoes (12 %) and shoes with arch supports (11%). seventy three percent o f the players wore the same shoes for practices and matches. tw enty percent wore "tackies" for the practices and hockey boots for matches. hockey was most frequently played on grass (97% ). o ther surfaces sometimes played on included synthetic surfaces and soil. fifty percent o f the players had sustained injuries as a re­ sult o f hockey during their hockey careers. the total number o f injuries recorded was 130, 75 (58%) o f which oc­ curred in the 1990 hockey sea­ son. the most frequent injury was an ankle injury (27% ), fol­ lowed by 15 % o f knee injuries and 8,5% o f low er leg pain. facial injuries were reported by 7,6% and quadriceps inju­ ries by 7% . o ther injuries mentioned included back inju­ ries (5% ), thumb and finger injuries (4% ), whilst shoulder and foot injuries each totalled 3%. when com paring southern transvaal and griqualand west first team hockey players, it was evident that significantly m ore first team southern transvaal school hockey play­ ers played club hockey than g riq u a la n d w est p lay ers (p = 0,048) (table 3). f ur­ ther, more southern transvaal than griqualand w est players played indoor hockey at school (p = 0,008), whereas more griqualand west players played indoor hockey at a club (p = 0,028). both groups o f players started training before the start o f the season. the differences in time spent on activities during a hockey practice are given in table 4. before a hockey match, g ri­ qualand w est warm up for longer (25 min) than southern transvaal (20 min) (p = 0,027). no significant difference was found in the activities o f the continued on pg 14 ---------------------------------------------------------------------------------- 11 sportgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) [s3) r elifen 500 tablets 500 mg n ab u m eto n e. reg no r / 3 . 1/265 w h e n y o u r p a t i e n t ’s in p a in , y o u r first r e s p o n s ib ility is t o t a k e a w a y t h a t pa in. q u i c k l y . effectively. b u t d o in g so could lead to unacceptable g a stro­ intestinal side effects a n d c o m b i n a t i o n th e r a p y . b u t n o w , ten ye a rs o f p rec is ely targ e te d m o le c u la r rese a rc h have p r o d u c e d a h i g h ly effective, n o n a c i d ic a n t i i n f l a m m a t o r y . relifen. e a c h tab le t is m a d e o f 500 m g n a b u m e t o n e , a n o n s t e r o i d a l a n t i i n f l a m m a t o r y , p r o v e n in n u m e r o u s d o u b l e b lin d s tu d ie s to be as effective as o t h e r b e n c h m a r k n s a i d s . yet its r o u t e o f a c tio n is t o ta lly different. relifen is a n o n a c i d ic p r o d r u g . in the s t o m a c h , it is relatively inactive. i t is a b s o r b e d f r o m t h e d u o d e n u m , i n to t h e p o r ta l b l o o d s u p p ly . fina lly, in t h e liver, it is m e t a b o li s e d in to a p o t e n t i n h i b i t o r o f p r o s t a g l a n d i n synthesis. r e f e r p a c k a g e i n s e r t f o r f u l l p r e s c r i b i n g i n f o r m a t i o n . f u r t h e r i n f o r m a t i o n is a v a i l a b l e f r o m o u r m e d i c a l d e p a r t m e n t . s m i t h k l i n e b e e c h a m p h a r m a c e u t i c a l s p o b o x 3 4 7 b c r g v l e i 2 0 ^ * r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) relieving his pain is pretty sporting of you, old chap. but do you have to get him high on acid? i rt '' * t h e active m e t a b o li te p e n e tr a t e s t h e s y n o v ia l fluid to reach t h e in fla m e d site, giving effective relief °f s y m p t o m s . e x c r e t io n is b y t h e k id n e y s , so g a s tr o ‘ntestinal d a m a g e t h r o u g h biliary re c irc u l a t i o n a n d reflux is unlikely. f o r effective relief f r o m pain and inflam m ation, with less c h a n c e o f g a s tr o i n t e s t in a l d i s c o m f o r t , y o u now have an ideal c hoice. relifen. ^clifen an d th e s b lo g o a re tra d e m a rk s . o g il v y & m a t h e r , r ig h t f o r d s e a r l e -t r ip p & m a k in 5 4 9 8 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) hockey table 4: differences in time spent on activities during a hockey practice a ctivity s o u th e r n t ra n s v a a l g riq u a la n d w est p -v alu e d ribbling 20 min. * 10 min. 0,000 stretching (before training) m ean tim e = 5-10 min. distribution = 0 > 1 5 min. mean tim e = 5-10 min. distribution = 0 1 5 mi n 0,013 stretching (after training) < 5 min. > 5 min. 0,023 * m in. = m inutes table 5: differences in injury patterns between southern transvaal and griqualand west i n ju r y s o u th e r n t ra n s v a a l g riq u a la n d w est incidence incidence n* % n* % k nee injuries 11 19,6 8 10,7 a nkle injuries 10 17,9 25 33,3 injuries to face and head 5 8,9 5 6,7 t high m uscle injury 3 5,4 6 8 l o w er leg overuse 2 3 ,6 9 12 injuries o th er injuries ** 25 4 4,6 53 29,3 n = num ber o f players t h e category "other in ju ries” com prises 21 additional types o f injuries, each having been sustained by a sm all num ber o f players. players included in their warm up. a significant difference (p = 0,005) was found in the type o f shoes worn for hockey. jogging shoes were worn by 4% o f the southern transvaal players, while 19% o f the g ri­ qualand west players wore them. significantly more south­ ern transvaal players (95%) wore hockey boots when com ­ pared to griqualand west pla­ yers (75%) (p = 0,001). south­ ern transvaal players appeared to have played hockey on synthetic surfaces m ore fre­ quently than griqualand west players. forty percent o f southern transvaal players and only 25 % o f griqualand west played on synthetic surfaces (p = 0,044). the griqualand w est play­ ers played more frequently on soil than southern transvaal. only 13% o f the southern transvaal players played on soil, while 50% o f the griqua­ land west players played on soil (p = 0,000). however, when players were asked to list all injuries ever sustained during previous hockey seasons, including 1990, no significant differences were found in the number o f injuries per injured player. there was a difference in the injury pat­ tern between southern trans­ vaal and griqualand west (table 5). both groups o f hockey players recorded the highest amount o f injuries for the first 6 months o f that cur­ rent year (1990), followed by 1989 and the second half o f the year 1990 up to the date o f completion o f the questionnaire. no significant difference was found between southern trans­ vaal and griqualand west in the incidence o f lower leg over­ use injuries in the 1990 hockey season (25,33% o f southern transvaal vs. 29,27% o f gri­ qualand west players). coaches tw elve choaches, two o f which were male and equally repre­ senting the southern transvaal and griqualand w est, com ­ pleted the questionnaire. eighty three percent o f the coaches had completed hockey instruc­ to rs’ courses and examinations, with 55 % o f the coaches hav­ ing had more than 10 years o f coaching experience and 83% having played at provincial or international level. all coaches reported inclu­ ding pre-season training in the hockey training program m e o f their players. in all cases this pre-season programme included stickwork and stretching, while most (75% , n = 9) included combinations o f sprinting and jogging. the mean frequency o f re­ ported pre-season training was twice a week, increasing to twice or three times a week during the season. pre-season prac­ tice sessions mostly lasted between 45-60 minutes while sessions increased to 60-90 minutes during the season. the main differences in the 14 ------------------------------------------------------------------------------sports medicine vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) hockey program m es before and during the season were that endurance training was allocated 10-15 minutes pre-season while only given 10 minutes in season. stickword received more at­ tention in the season (20 min­ utes per session) than in the pre-season period (15-20 min­ utes a session). all coaches emphasised a stretching pro­ gram m e and taught their play­ ers to stretch before training and matches. the coaches, how­ ever, maintained that most players did not stretch after training o r matches. the coaches expressed the opinion that it was necessary for the players to wear hockey boots and reported that both practices and matches were gen­ erally played on grass surfaces. according to the reports o f the coaches, 30 injuries were sustained as a result o f which a total o f 67 practices and 22 matches were missed during the 1990 hockey season. the most frequent injuries reported by the coaches in the 1990 sea­ son were lower leg overuse injuries (13 players = 43% ), followed by the knee (6 players = 20%) and ankle injuries (5 players = 17%). two players had lower back problems while one -player each had a wrist, hip, nose or thumb in­ ju ry . hockey practices were mostly missed due to knee in­ juries, followed by lower leg overuse injuries and ankle inju­ ries. m atches were mostly missed due to knee injuries and lower leg overuse injuries. only 54% o f the coaches (n = 12) emphasised strapping after injury, while 64 % were in favour o f physiotherapy. most did not emphasise strength training and proprioceptive ex­ ercises. other post injury reha­ bilitation measures mentioned by the coaches were cool-down stretches after practices or matches, rest, and rubbing in some ointment. discussion the most significant finding o f this study was that half o f the players had sustained injuries as a result o f hockey ever since they had started playing the sport. this can be considered a high injury rate and the need for education on hockey inju­ ries is self-evident. a further important finding o f this study was that ankle, knee and lower leg overuse injuries were the most com ­ monly reported by the players (n = 157). this correlates with the most commonly found run­ ning injuries which are o f the ankle and knee.3'5 from the findings o f this study it would thus appear that education will have to be geared towards these injuries and their aetiology. firstly, the high incidence o f ankle injuries can be attri­ buted to the sudden stop-start actions and changes o f direc­ tion needed in hockey which place strain on the ankle liga­ ments. according to verow6 the use o f shoes with studs on artificial surfaces increases the instability o f the ankle and therefore the risk o f ankle inju­ ries. when wearing hockey boots while playing on grass, the foot may move inside the shoe for any twisting move­ ment since the shoe is anchored on the ground. more ankle injuries occurred amongst the griqualand west players when compared to the southern transvaal players. this could be due to their harder playing surfaces and the greater length o f time the gri­ qualand w est players spent on soil. in addition, the fact that the griqualand west players did not wear hockey boots to the same extent as the southern transvaal players could have placed the griqualand west players at a higher risk o f ankle injury. the hockey boot has greater mobility on soil than on an artificial surface or grass, leading to less strain on the ankle. this explains the differ­ ence in our findings, when compared to those o f v erow .6 secondly, knee ligament injuries may result from a rotatory force on a flexed knee, which can occur due to quick changes o f direction or a knock on the flexed knee. wearing studded shoes, more movement will occur at the knee during quick changes o f direction since the shoe cannot move on the playing surface. sustained positions o f knee flexion such as required in hockey, pose much strain on the patello femoral jo in t and may give rise to anterior knee pain. the greater incidence o f knee injuries am ongst southern transvaal players may thus be attributed to the fact that south­ ern transvaal players wear hockey boots m ore frequently. thirdly, although direct blows to the shin occur in hockey, doing too much, too soon and too hard all play a role in the incidence o f intrinsic or overuse injuries o f the lower leg7 among hockey players. the frequent changes o f direction and jarring on the lower leg also increase the risk o f overuse injuries. ---------------------------------------------------------------------------------- 15 sportgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) hockey when recording all injuries sustained during their hockey careers, more griqualand west than southern transvaal players indicated lower leg overuse injuries. the hard ground in the griqualand west region and the fact that the griqualand west players play more often on soil than their southern transvaal counterparts, may have increased their risk o f low er leg overuse injuries. in addition to these major sets o f aetiological factors re­ sulting in injuries o f the ankle, knee and lower leg in hockey, verow6associates injuries with playing position. he reports that injuries found in goal­ keepers included direct trauma from sticks and the ball, head injury, loss o f a testicle, rotator cuff strain (d.t. falling on the outstretched hand), olecranon and trochanteric bursitis from landing on these parts. on the other hand, outfield -p lay ers were reported having suffered lacerations around the head, muscle injuries and strains to the lower back and upper leg areas due to running or twisting in a stooped position. further, he points out that synthetic surfaces give rise to more grazes and the use o f studs on these surfaces increases the instabil­ ity o f the ankle. as a whole, the coaches were well qualified and had extensive hockey coaching experience. coaching methods such as pre­ season training o f shorter dura­ tion than the training in season and the emphasis on pre-season endurance training tend to re­ duce the risk o f overuse injury. however, it is o f concern that the coaches mentioned the fact that hockey players do not appreciate the importance o f post-m atch/practice stretch­ ing. the introduction o f greater emphasis on this aspect o f in­ ju ry prevention is thus advo­ cated in the training o f hockey players and their coaches. the unanimous opinion ex­ pressed by the coaches that players should wear special hockey shoes is o f interest. this observation is in keeping with the rationale that hockey boots facilitate the quick change o f direction and acceleration and deceleration which are com ­ mon in the game o f hockey and thereby reduce the stress on the lower leg muscles with con­ comitant reduction in muscle injuries o f the lower leg, par­ ticularly when, as reported, this is prim arily being played on grass. the coaches report a much lower incidence o f injuries amongst their players in the 1990 season than the players do (coaches report a total o f 30 and players a total o f 75 inju­ ries). it therefore appears that coaches are not always aware o f the inj uries sustained by their players and are therefore not in the position to make the necessary modifications to the training programmes o f these players. this may lead to a worsening o f existing injuries. in order to prevent injuries and to aid rapid recovery from injuries, it is essential that there should be good communication between players and coaches. coaches need to be aware o f their players’ injuries in order to modify their training pro­ grammes or to be able to advise them to seek medical attention. conclusion we thus conclude from this prelim inary survey o f high school hockey players that greater awareness and educa­ tion o f the hockey fraternity in terms o f factors predisposing to hockey injury is essential, if the high incidence o f injury re ­ ported in this study is to be reduced. as has occurred in so many o f the more frequently researched sports, awareness of the aetiology o f injury is a first step towards taking precautions to prevent the occurrence o f intrinsic or overuse injury. with regard to the discrep­ ancies which existed between the injuries reported by the coaches and players, this can be attributed to the fact that coaches are not always aware o f the injuries sustained by their players and therefore not in the position to make the necessary modification to the training program m es o f these players. this curcumstance increases the risk o f injury. good com m uni­ cation and trust between play­ ers and coaches are essential and a deliberate attempt to achieve this, needs to be made. acknowledgements the authors are indebted to the following persons for their assistance and would like to express their gratitude to karen rosen-allan, sandra jordaan, the d epartm ent o f biostatistics o f the csir, as well as all the participating coaches and play­ ers. financial assistance for this project was provided by the snaar viljoen grant, u niver­ sity o f the w itwatersrand. references on request. 16 ------------------------------------------------------------------------------sports medicine vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy comrades marathon 1992 at the comrades m arathon up run this year, 9 elastoplast sta­ tions were manned by 120 physiotherapists under the ban­ ner o f the natal sports interest group o f the south african society o f physiotherapy. these helpers consisted o f practising natal physiotherapists, physio­ therapy students from the uni­ versity o f durban-w estville, final year physiotherapy stu­ dents from wits university and two physiotherapists from northern transvaal. as usual we were sponsored by smith and nephew whose employees led by dave dunn, worked unstintingly to make the day a success. they supplied all the necessary medical parapher­ nalia to make the runners life easier and, as in the past, they donated literally miles o f strap­ ping. this year, approximately 45 helpers were on hand to record the injuries o f the runners treated at the stations. at my station, most o f these helpers were doctors. the data is now being analyzed. again, as in the past, neither the physiotherapists nor smith and nephew received any ac­ knowledgement. w e were ignored by the media and even though we asked that the tv cameras focus on the physioth­ erapists at work, we were passed over. at a pre-smith and nephew lunch party, where i, on behalf o f all the physiotherapists, was thanked for the outstanding joyce morton w ork we do, a prominent "running" doctor was overheard telling a novice that at all costs, never stop at a physiotherapy station, but to just keep going and run through her problem! working in the red cross tent in pietermaritzburg, i asked my patient, who had been ad­ mitted for other reasons, whether the bandage on his knee had been o f any help. he explained to me that he had been doing too much hill work and that he had developed an iliotibial band friction syn­ drome. hoping that it would not be aggravated by the long run, he entered the race but by the time he reached inchanga, he realized that he could not continue without help. he stopped at an elasoplast station where he was strapped and given some advice. he told me that without the strapping, he would never have finished. the patient lying in the next stretcher, who was a doctor, proceeded to give my patient a lecture about the fact that an itb is a friction syndrome and that the physiotherapist’s judge­ ment in strapping the knee, was completely incorrect. as the doctor’s own judgem ent was so bad that he had landed up in the tent with excruciating cramps, i thought it was not really the time to argue with him. physiotherapists do know the pathology o f an itb and other running problems. we deal with them every day of our working lives. but even in medicine there is a word called "empiricism" and if that strap­ ping helped that runner to achieve his goal, even though the "book" says it was wrong, must we deny him his moment o f glory? every year we are inundated with thanks from runners who state categorically that they would never heave reached the finish without the help o f the physiotherapists. the physio­ therapists hear these thanks, but no one else does. the natal technicon re­ search d epartm ent, who is handling our data, will be look­ ing for the runners who stopped at m ore than one station. ques­ tionnaires will be sent to them asking them whether they did complete the race and whether subjectively, they felt that they were helped by the physiother­ apists. does it matter that much if their answers are subjective? the comrades m arathon is a fun race for thousands o f runners and even more specta­ tors. on the day, the physio­ therapists and their helpers give o f their time voluntarily. smith and nephew spend literally thousands o f rands on the event, as a fight to the physiothera­ py profession and to the run­ ners. surely this is an ideal opportunity to show the public what the medical profession can do for them? surely this is not the time for our medical colleagues to criticise us, espe­ cially without giving us the right to reply? ---------------------------------------------------------------------------------- 17 sportgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) proline supports w ith th re e years design d e ­ v e lo p m e n t and sales behind th e m , th e e ng in e erin g and m a rk e tin g s t a f f a t proline s u p p o rts k n o w th e y have a s u c c e s s fu l range of p ro d u c ts to c o v e r m o s t a p p lic a tio n s in the lim b s u p p o rt and d e fe n c e m a rk e t w ith so m e e x c itin g a d ­ d itio n s on th e w a y . t h e m a rk e t a t p re se n t is s p lit in to th r e e d is t in c t categories, the firs t is the basic use o f s u p p o rts as an e ffe c ­ tiv e m e a ns o f d e fe n c e a g a in s t in ju ry d urin g rig o ro u s s p o rtin g a c tiv itie s . u n fo rtu n a te ly th is represents the sm allest aspect o f th e m a rk e t because s p o rts m en and w o m e n alike o nly begin to th in k a b o u t p re v e n ­ tio n a fte r the dam age is done. s e c o n d is th e s itu a tio n w h e re people w e a r s u p p o rts to p ro te c t the in ju rie s th e y have re ce ive d during s p o rt. t h ird is th e v e ry u n fo r tu ­ nate p o s itio n w h e re s u p p o rts are w o rn long a fte r people have s to p p e d c o m p e tin g , b ut have to w e a r a s u p p o rt to enable th e m s e lv e s to lead a n o rm a l life . m o s t o f the se ca ses are v e ry sad e s p e c ia lly w h e n you co n s id e r th a t a lo t o f th e p ro b le m s co uld have been a vo id e d if som e fo rm o f protection had been envisaged. o f co u rse m o s t o f th e s u p ­ p o rts have o n ly re c e n tly been m ade a va ila ble due to the n e w hi-tech m aterials necessary fo r th e ir c o n s tru c tio n . the o b v io u s c o n c lu s io n is th a t p ro b le m s in th e se co n d and th ird s e c to r are s till lik e ly to e x is t u nless th e a d v a n ta g e s o f s u p p o rts are fu lly e xplaine d to and a c c e p te d by p a r tic i­ p an ts o f all s p o rts w h e re lim b in ju rie s are a p o s s ib ility . in v e ry m a n y sp ecialize d s p o rts th e use o f p ro te c to rs and b o d y a rm o u r is an e x ­ p e cte d and a c c e p te d p a rt o f pinto hinged knee support th e p a rtic ip a n ts a tire . t h e re ­ fo re it is n o t u n a c c e p ta b le fo r lim b s u p p o rts o f all ty p e s to be used as an e ffe c tiv e m eans o f p ro te c tio n by c o m p e tito rs in a w id e v a rie ty o f s p o rts . so fa r o n ly s p o rtin g p ro blem s have been d e a lt w ith , b u t proline s u p p o rts are e q u a lly s u ita b le fo r use by s u ffe re rs of m any co nd itio n s associated w ith lim b s and th e lo w e r b ack fro m dam ag e d te n d o n s and lig a m e n ts to som e a rth ritic a il­ m e n ts. proline m ake s u p p o rts to s u it v e ry m a n y d iffe r e n t a p p li­ c a tio n s and a g re a t deal of c o n s id e ra tio n is a lw a y s d i­ re cte d to th e area o f user co m fort. each model has been d esigned to do a p a rtic u la r job b u t also to be w o rn fo r long periods. the supports and their applications wrist & ankle these s u p p o rts reduce the w a rm -u p tim e th e re fo re m a k ­ ing th e te n d o n s m ore e la s tic and less like ly to s u ffe r d a m ­ age. t h e y also im p ro v e c irc u ­ la tio n b e lo w the s kin also around and into the ankle, w rist k n u c k le and fin g e r jo in ts th e re b y re d u cin g th e possib lity o f c ra m p as w e ll as p ro v id ­ ing p o s itiv e s u p p o rt to o v e r­ s tre sse d or d am ag e d w ris ts and a n kle s. t h e y are ideal fo r speeding up joint recovery after p la s te r c a s ts h ave been re ­ m o ve d fo llo w in g te n d o n or bone dam ag e . elbow e lb ow s u p p o rts do b a sica lly th e sam e th in g as ankle and w r is t, b u t w ith m ore e m p h a ­ sis on m u scle s u p p o rt and th e rm a l d e fe n c e fo r o v e r­ stressed tendons th a t give rise to p ro b le m s c o m m o n ly k n o w n as "te n n is e lb o w ” . thigh & calf the th ig h and c a lf are su p ­ ports providing d ire ct pressure fo r m u scle a s s is ta n c e and e x c e lle n t th e rm a l b e n e fits to speed up th e n a tu ra l repair o f to rn m u scle tissu e . knee knee s u p p o rts are th e m o s t _________ _______ j 18 ---------------------------------------------------------------------------sports medicine vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) c o m p lic a te d , th e y are a v a il­ able in tw o d is tin c t v a ria tio n s : hinged and n o n -h in g e d . n o n -h in g e d are neoprene sle e ves w ith or w ith o u t s tra p s . b oth ty p e s o ffe r v e ry good m u s c u la r s u p ­ p o rt and s ta b ility . the s tra p p e d v a rie ty o ffe r in ­ s ta n tly va ria b le te n s io n to lo w e r thigh and upper calf. the sleeve m a te ria l on all knee supports provides the same benefits as described for calf and thigh supports. h inged knee types are very s o p h is tic a te d . t h e y p ro ­ vid e im m e n se p ro te c tio n and are a va ila ble in t w o d e sig n s, n a m e ly th e tw o stra p (" p in to ") or th e m ore ro b u s t fo u r stra p (" m u s ­ ta n g "). t he a s s is ta n c e p ro v i­ ded fro m a hinged su p p o rt is q u ite re m a rka b le . be­ cause o f its m e ch a n ica l s tre n g th , it p ro vid e s th e knee jo in t w ith a big b oo st to its p o w e r to re s is t the u n n a tu ra l m o v e m e n t of h y p e r-e x te n s io n , tw is tin g diamond body belt and la teral m o v e m e n t th e re b y a ffo rd in g e n o r­ m ous p ro te c tio n a g a in st firs t tim e in ju ry as w e ll as d e fe n d in g dam aged knee jo in ts fro m fu rth e r a g g ra ­ v a tio n . a p o in t w o rth n o tin g is th a t proline hinges are user frie n d ly and in th e e v e n t o f e x tre m e pressure th e y b ecom e s a c rific ia l. t h e y are also hand fin ish e d fo r tifie d n ylo n (n o t steel) and are generally accepted fo r use in c o n ta c t s p o rts , b ecause o f th e ir p a te n t th re e piece s a fe ty design, a t th e d is c re tio n o f the v a rio u s g o v e rn in g bodies and re fe re e s , e tc . b ody belt the u niqu e s u p p o rt o ffe re d by th e p roline b o d y b e lt has be­ co m e fu lly re co g n ize d by s p o rts m e n and w o m e n and b a ck s u ffe re rs a like , m aking th is la te s t e d itio n to th e pro­ line range a b e st seller in its fie ld . r etaining th e sam e fo r­ w a rd th in k in g and e m p lo yin g double th ic k n e s s neoprene, its th e use o f t w o re m o va b le c e n tra l pads th a t m a ke s th is b e lt tru ly a d ju s ta b le to su it the unique shape or p ro b le m s of th e p a rtic u la r w e a re r. the biggest com plim ent has c o m e fro m people w h o have s u ffe re d fo r m a n y years w ith b a ck pain and n o w fin d tr e ­ m e n d o u s re lie f w ith a proline b elt. a ll proline p ro d u c ts provide a va lu a b le degree o f im p a c t p ro te c tio n . m tc ro c e llu lo r c losed cell c e n te ro l lining fo r ro p id w o rm -u p p e rio d s o n d e x tro shock a b s o rb in g p ro te c tio n n y lo n o u te r sleeve o p e n a re o ossists p otello s u p p o rt g e n u in e 'v e lc ro ' b ra cin g straps edges b o u n d f o r c o m fo rt 'skin f rie n d ly ' n ylo n in n e r lin in g s culptured shope fo the re o r o f sleeve p re v e n ts c h o fin g pivot blades m o n u fo c tu re d fro m hi-stress fo r tifie d nylon p r o v id in g e x c e lle n t lo te ro l o n d o rs io n o l s ta b ility p otent " e o r l y lock a n ti h yp e re x te n s io n buffers b u ffe rlin k g u id e p lo te w ith fo ld b o ck fe o tu re to p re v e n t h in g e b a r p ro tru s io n th ro u g h sleeve hinged knee supports: new im proved design for greater com fort "proline supports" available from aj oates engineering & marketing positive protection from positive thinking c o n ta ct tel: ( 0 1 1 ) 6 1 6 6 4 1 7 fax: (0 1 1 ) 6 1 6 -1 1 2 7 all hours -------------------------------------------------------------------------------------19 sportsgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket cricket injuries of the south african team at the world cup and in the caribbean: the physiotherapy perspective craig smith keywords: cricket, international tours, injuries, physiotherapy. abstract this paper discusses the injuries which were encountered during the two tours by the south african cricket team to the world cup and the caribbean islands. the anatomical site most at risk was the lower limb and the structures most commonly injured were the bones/joints and the muscles. fielding, batting and bowling all contributed towards injury. further investigation into this subject should include intrinsic and extrinsic causes, the structures most at risk and injury side dominance. in t r o d u c t io n recently, the literature has demonstrated a growing inter­ est in the subject o f cricket in­ juries, especially those associ­ ated with tours to and from this craig smith, bsc physiotherapy, bsc (med) (hons) sports science. physiotherapist, south african team. sports injuries clinic, university o f cape town. co u n try .1,2,3 it is this stimu­ lated interest and approach to the subject that will soon begin to reveal new evidence regar­ ding injuries encountered un­ der these circumstances. the fruits o f this w ork will become evident when the results are translated to the actual play and begin to show on the field in the form o f a decrease in the incidence o f injury. the purpose o f this paper is thus to report on the injuries which were encountered at the world cup tournament and during the subsequent tour to the caribbean where a series o f matches were played against the w est indies team. t h e w o r l d c u p n in eteen squad m em bers made up the south african contingent, being comprised o f 14 team players, 2 players to gain experience and help with practices and a coach, physio­ therapist and team manager. the squad was away for two months and played a total o f 6 w arm -up games and 9 world cup matches. training ses­ sions were held on non-match 20 ------------------------------------------------------------------------------sports medicine vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cmicket days which incorporated a warm-up routine, batting and bowling in the nets and fielding practice. w arm -up stretching and technique practice was also done on match days. injuries and treatment all 16 players received treat­ ment. there were a total o f 56 separate injuries with the most commonly affected area being the thigh. the most common cause o f injury was fielding with batting, bowling and gen ral running also contributing. the muscular structures were affected most, followed by in­ jury to the bones/joints and the tendons. ligamentous and cartilaginous structures were least affected. one player was treated for 6 injuries, four play­ ers for 5 injuries, three players for 4 injuries, two players for 3 injuries and six players for 2 injuries. only one player was severely injured warranting his exclusion from team selection for a match. an account of some o f the commonly experi­ enced injuries and their treat­ ments are briefly discussed. head and neck one player suffered with chronic cervical facet joint syndrome for which he received spinal mobilisation treatment and trigger point acupressure to relieve the associated muscle tension. spine and trunk there were a total o f 7 injuries involving the thoracic and lumbar spines, although none serious. two players suffered injury to their iliolum bar liga­ ments which responded well to spinal mobilisation treatment. one o f the bowlers complained o f chronic lumbar stiffness and pain. he had a history o f mild scheurm ann’s disease with a slight scoliosis and marked quadratus lumborum spasm. a nother player developed "rib tip", a stress injury involv­ ing the teno-osseus attachment between the stomach muscle and the rib cage. a potentially serious and debilitating injury among fast bowlers, it did not hinder him too much and actually got better as the tour progressed with cross-friction, ultrasound and laser therapy. finally, one player strained his external oblique abdominal muscle while batting. he was treated with cross-frictions and ultrasound and the area was strapped to assist him in the next match. upper limb an all-rounder suffered with a chronic shoulder impingement syndrome which would flare up after he had done much bowling or throwing. this would then affect the rest of his shoulder complex leading to infraspinatus and trapezius muscle spasm requiring mo­ bilisation and massage treat­ ment. four elbow injuries oc­ curred in the first week as a result o f the players having to adapt to the large australian fields by throwing the ball far distances. these "sprained" elbows healed quickly after 2 to 3 days o f treatment. three players injured the soft tissues overlying the meta­ carpophalangeal (mcp) joints. the wicket keeper brusied the second m cp joint o f his right hand by constantly having to catch the ball during practices and matches. initial x-rays ruled out a fracture and a cortisone injection was given to relieve the pain and swelling and he continued playing with extra padding inside his gloves. the reserve keeper also injured his left hand in the same manner, yet his injury was not as severe. another player bruised his fifth m cp joint o f his left hand from constant fielding o f the ball. lastly, one player developed tendinitis o f his extensor pol licis longus tendon in the right wrist. this responded well to cross-friction treatment, laser and ultrasound. o f the four finger injuries, the most serious was that o f the captain who was hit with the ball on his left thumb nail. the pain and swelling persisted for a couple o f days regardless of continual puncturing o f the nail to help it drain and only a week later when the nail came off, was he provided with some relief from the painful syndrome. lower limb four players bruised the front o f their thigh as a result of being hit with the ball through their protective padding. one player strained his quadriceps muscle while 4 others reported mild pain and stiffness in their hamstrings which were treated on a precautionary basis. a fifth player slgithly strained his right hamstring during one of the matches and came o ff the field temporarily for treatment and strapping support. h e was later treated with vigorous cross-frictions, ice and ultra­ sound and two days later played again without further worry. one player tore his left adduc­ tor longus muscle two weeks before the team left and re­ ceived extensive treatment to ---------------------------------------------------------------------------------- 21 sportgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket enable him to recover in time. d uring the tour his groin often became stiff and painful and required occasional massage and ultrasound treatment. h ow ­ ever, during the final game, he subsequently strained the right groin while fielding and could not continue playing. another player had pain on the outside o f his left knee, diagnosed as a lateral meniscal cyst, which was aggravated when bowling. on examining his bowling action and infor­ ming him to place his front foot in a m ore straightened posi­ tion, his symptoms cleared up shortly. (however, it is thought that this change may have brought about a new injury to his ankle). two others had in­ juries involving their iliotibial bands which did not completely clear up and required on-going maintenance treatment during the tour. lastly, another deve­ loped popliteus tendinitis early on which responded well to treatment. injuries to the lower leg in­ cluded two calf muscle strains, two achilles tendon strains, and mild shinsoreness (tibial stress syndrome) in one o f the fast bowlers. the serious calf muscle strain occurred while the player was batting and un­ fortunately he could not come o ff the field immediately. he was treated extensively there­ after, yet unfortunately had to miss the next match as his in­ ju ry had not healed sufficiently and the risk o f further injury with im portant matches loom ­ ing was too great. the wicket keeper developed a secondary achilles tendon strain as a result o f his sprained lateral ankle ligaments. m ore so, his injury was also aggravated by the prolonged crouched position he had to field in and he only just recovered before the first match began. the shinsoreness was managed with ice, ultrasound and shock absorbing inner soles. two ankle sprains occurred in non-cricket related incidents, and recovered following ice, cross-frictions and ultrasound therapy. lastly, an all-rounder injured his left tibialis pos­ terior tendon about half way through the tour. he became aware o f pain next to his left medial malleolus during foot strike o f his bowling action. initially it was thought that he had a posterior talar impinge­ ment injury (talar spur) and x-rays revealed the presence o f an enlarged os trigonum. he was given a cortisone injection into the area and rested. however, the symptoms only got worse when he played again and the pain spread to the achilles tendon. on returning home, inflammatory exudate in the region o f the tibialis pos­ terior tendon was evident with an mri scan. the caribbean tour the team o f 14 cricketers which toured the caribbean islands played three 1-day interna­ tionals and one 5-day test match against the west indies team. the team followed the usual exercise procedures while on tour and three o f the players had minor injuries carried over from the previous world cup tour. a total o f 15 injuries were reported with only 11 players requiring treatment. one player had 3 injuries, two players had 2 injuries while the other eight players each had 1 injury. the most commonly injured structures were the bones/joints followed by mus­ cular injuries. the causes o f injury were evently spread among batting (3), bowling (4) and fielding (5). head and neck one player sustained a subluxed facet jo in t to his cervical spine during the 5-day test match when he ducked out o f the way o f a rising ball while batting. he had to continue batting for an hour before he could receive treatm ent in the form o f heat, a manipulation, ultrasound and a muscle relaxant. this enabled him to continue in less discom­ fort and he later responded well to further treatment with spinal mobilisations. spine and trunk two bowlers were treated for chronic lumbar pain and stiff­ ness. another bow ler injured his right costochondral jo in t o f the fourth rib. he had collided with another player’s head while body-surfing and when he had to bowl two days later, he broke down in his third over complaining of severe chest pain with breathing and much diffi­ culty bowling. he immedi­ ately came o ff the field to apply ice to the chest and went for x-rays which excluded a cracked rib. his chest was largely swollen, yet following five days rest and treatment with ice, laser and ultrasound 4 times daily coupled with anti­ inflammatory medication, his injury healed to the point where he played the test match with supportive strapping, yet no recurrence o f the painful symp­ toms. 22 ■ — — — sports medicine vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket table 1: anatomical injury profile world cup west indies anatom ical site head and neck 5% 13% 3 2 upper limbs 27% 27% shoulder 2 1 elbow 4 — wrist/hand 4 1 fingers 4 2 trunk and spine 18% 27% chest/abdomen 3 1 spine 7 3 lower limb 50% 33% hip 1 — thigh 13 2 knee 5 2 lower leg 5 — ankle 4 — foot/toes 1 total 56 15 in ju re d s tructures bones/joints 16 9 muscles 23 3 tendons 11 1 ligaments 4 — cartilage 1 1 soft tissue 1 1 total 56 15 upper limb one player suffered a haema toma injury to his right wrist whereby on attempting to catch a batsman out he was struck on the volar surface causing a blood vessel to burst, with immediate swelling into the area. this had apparently occurred on a previous occasion and applying ice and a compression bandage to the wrist reduced the swel­ ling and he could continue play­ ing. another player dislocated his distal interphalangeal joint o f his right middle finger but this was easily reduced and treatment ensured he could play the test match 2 days later. lower limb one player strained his rectus femoris muscle which hampered him for the first half o f the tour as he could not rest it suffi­ ciently . another bowler mildly strained his right groin towards the end o f the tour yet could continue playing. a third p re­ sented with symptoms o f a mild synovial plica syndrome in­ volving his right knee. he had a history o f previous injury to the knee which required a menisectomy a few years back. the knee responded well to mobilisations, ultrasound and laser therapy. the last two injuries were both as a result o f players being hit with the ball causing moderate periosteal and soft tissue bruising to the knee and dorsum o f the foot respectively. discussion the injuries associated with the south african cricket team ’s tour to the w orld cup and west indies have been presented. this paper adds to the already present and growing amount o f data reported in the literature on this subject. tables 1 and 2 give an account o f the anatomi­ cal injury profiles and the phys­ iotherapy treatments given. the incidence o f injury as­ sociated with the w orld cup tour was 3,5 per player while that o f the caribbean 1 injury per player. these figures sup­ port m orton’s3 hypothesis that the injuries encountered on cricket tours may be propor­ tional to the length o f the tour. h er results demon stated an injury incidence o f ju st 1 per player for a squad o f 17 players with a total o f 22 injuries. al­ though the number o f injuries seem to increase with the length o f the tour, a more true per­ spective o f the incidence may be found when the total number is compared to the number o f players injured. this then ad­ justs the caribbean tour inci­ dence to 1,4 and the natal tour to 1,7 per player. applying the same adjustment to the tour o f india' also results in an inci---------------------------------------------------------------------------------- 23 sportgeneeskunde vol. 7 no. 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket t able 2: physiotherapy treatment modalities world cup west indies players 16 14 players treated 16 11 treatments given 232 85 t re atm en t m odalities electrical interferential 16 3 ultrasound 176 60 lasesr 85 42 total 111 105 manual mobilisations peripheral 20 23 spinal 23 17 massage non-specific 17 6 frictions 85 13 acupressure 13 18 t otal 158 77 ice 81 40 strapping 29 10 stretching exercises 15 injections 4 total 129 50 total treatment modalities 564 232 t able 3: causes of injury world cup west indies batting 14 3 bowling 11 4 fielding 15 5 running (not during cricket) 11 1 other 5 2 total 56 15 dence increase from 1 to 1,8 per player. the lower limb was found to be the commonest area injured on the two tours (50% and 33% ), followed by the upper limbs (27% and 27%), the trunk and spine (18% and 27% ) and then the head and neck (5% and 13%). on both tours, fiel­ ding accounted for most o f the injuries (20), followed by bat­ ting (17), bowling (15), non­ cricket relating running (12) and other causes (7). (see table 3). in conclusion, it can be said that despite detailed prepara­ tion and precautionary meas­ ures, injuries will almost cer­ tainly result from the normal nature o f the game and circum ­ stances which cannot always be completely controlled. there­ fore, it is clear that a continued awareness and vested interest in this field can only be height­ ened by reporting this data, which will hopefully lead to further insight into the manage­ ment and treatm ent o f cricket injuries and a reduction in the incidence o f these injuries in the future. areas which may warrant further investigation include the incidence o f injury related to intrinsic and extrinsic causes, identifying the high-risk struc­ tures associated with tours o f varying lengths and injury side dominance among batsmen and bowlers. effective measures to lim it injury in the form o f spe­ cialised training programmes, regular stretching plus prom pt treatm ent will continue to bene­ fit not only touring cricket teams but other tours o f this nature and assist our cricketers in the international competitive arena. refe r e n c e s 1. smith ca. c ricket injuries w hile on to u r w ith the south a frican team in india. sa j o u rn a l o f s ports m edi­ cine, 1992; 7(1): 4-8. 2. smith c a . sports injuries encoun­ tered on a five w eek international cricket tour. sa j o u rn a l o f sports m edicine, 1990; 6(1): 10-15. 3. m orton j. c ricket injuries o f the northamptonshire county cricket team during a 15 day to u r o f n atal. s/1 jo u rn a l o f sports m edicine, 1992; 7(2): 18-20. 24 ------------------------------------------------------------------------------sports medicine vol. 7 no. 4r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license strategies used by professional rugby union clubs to manage players for artificial turf exposure c d mckay,1 phd(kinesiology); m j cross,1,2 phd (health); s p t kemp,3,4 mbbs (medicine), msc (sports medicine); k a stokes,1,3 phd(exercise physiology) 1 department for health, university of bath, claverton down, bath, ba2 7ay, uk 2 premiership rugby, regal house, 70 london road, twickenham, tw1 3qs, uk 3 rugby football union, rugby house, twickenham stadium, 200 whitton road, twickenham, tw2 7ba, uk 4 faculty of epidemiology and population health, london school of hygiene and tropical medicine, keppel street, london, wc1e 7h t, uk corresponding author: c d mckay (c.d.mckay@bath.ac.uk) artificial turf is increasingly being used on rugby union pitches, both for training and competition. yet, despite growing popularity and governing body regulations on minimum pitch standards, there is concern about its potential to increase injury risk. two systematic reviews examining injury risk across football codes (football, american football, rugby union) found comparable injury rates between turf types, aside from a slightly increased risk of anterior cruciate ligament (acl) injury on artificial turf in american football[1,2]. although one study in football has suggested that teams regularly training on artificial turf have higher rates of acute training and overuse injury than clubs with natural grass home pitches[3], shifting between these two different surface types appears to have no effect on injury rates in this population[4]. in rugby union, fuller et al.[5] examined match injuries in six elite men’s teams in hong kong over two seasons and reported no differences in incidence between surface types aside from a small, but not statistically significant increase in acl injury risk (n=6; rate ratio=3.82; p=0.222). another study comparing single season injury characteristics between two professional teams, one with world rugby third generation certified artificial turf and the other with natural grass, found no difference in acute injury incidence between surfaces; however, overuse injuries appeared more likely on the artificial pitch during matches and in training[6]. williams et al.[7] conducted a small prospective cohort study in the highest level of professional rugby in england (premiership) and, in a sample based on a single pitch, found no clear differences in injury incidence, severity, or burden between surface types. notably, a prospective cohort study of two professional clubs (n=157 players) over three seasons demonstrated no overall difference in injury risk between grass (81.9 injuries/1000 match-hours, 95% ci: 72.2-92.5) and artificial surfaces (80.2 injuries/1000 match-hours, 95% ci: 69.9-91.7), but distinct injury patterns emerged (e.g. greater risk of foot injury on artificial turf)[8]. these findings are partially supported by ongoing injury surveillance across the premiership, where two of 12 clubs currently have artificial surfaces at their match venues. this long-term surveillance programme has shown that injury severity, and consequently burden, may be increased on artificial surfaces (5 year burden = 3015 days absence/1000 match-hours, 95% ci: 2768-3285) when compared to grass (2433 days absence/1000 match-hours, 95% ci: 23422527), largely driven by more severe hamstring, foot and toe injuries[9]. these results align with anecdotal accounts from the rugby community, where there are persistent concerns that artificial surfaces may be riskier[10]. altogether, this conflicting evidence base suggests that either artificial turf does not background: the use of artificial turf on rugby pitches is increasingly commonplace but there is limited evidence around its effects on injury, recovery, and performance. it is unclear whether this uncertainty influences player management strategies in professional clubs. objectives: to understand how professional rugby union clubs in england approach player management for artificial turf, to explore how the beliefs of medical and strength/conditioning staff influence these decisions, and to determine whether differences exist between clubs with different levels of exposure to artificial surfaces. methods: the study was a cross-sectional mixed methods study. twenty-three medical and strength/conditioning staff members from 12 english premiership rugby union clubs completed two bespoke questionnaires and participated in a semi-structured interview. results: two-thirds of the participants described formal club-level approaches to artificial turf. all participants from lowexposure clubs (<50% training and match time on artificial pitches) reported adjusting player recovery strategies following games on artificial turf to mitigate elevated muscle soreness and fatigue. clubs with artificial surfaces at their home venues were less likely to adapt recovery than clubs with natural turf pitches. regardless of exposure participants believed switching between surface types was a risk factor for injury. medics reported that acute injuries associated with artificial turf exposure typically occurred at the foot or ankle, whereas abrasions and overuse injuries were more common and often affected the knees, hips and lower back. players with compromised joints were less likely to be selected for matches on artificial surfaces. conclusion: player management around artificial turf is a focus for staff at professional rugby union clubs. club practices vary by exposure and may consequently influence injury risk estimates. keywords: rugby, football wounds, injuries, risk factors, environment, decision-making s afr j sports med 2020;32:1-7. doi: 10.17159/2078-516x/2020/v32i1a8276 mailto:c.d.mckay@bath.ac.uk http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8276 https://orcid.org/0000-0001-7664-3211 https://orcid.org/0000-0002-3250-2713 https://orcid.org/0000-0002-5049-2838 original research sajsm vol. 32 no. 1 2020 2 significantly increase injury incidence and there are misconceptions about its safety, or that players are being proactively managed to minimise their risk exposure, therefore affecting injury risk estimates. there is some evidence that coaches may have more positive opinions of safety on artificial turf than athletes[11], which likely has implications for player exposure to these surfaces during training and competition. in elite sport, medical and strength and conditioning (s&c) staff contribute significantly to these decisions as well but their beliefs and how greatly they influence practice are largely unknown. therefore, the primary purpose of this study was to understand how professional rugby union clubs approach player management for artificial turf. secondary objectives were to explore how the beliefs of medical and s&c staff influence these decisions, and to determine whether differences exist between clubs with different levels of exposure to artificial surfaces. methods this was a pragmatic, cross-sectional mixed methods study conducted from december 2016 – april 2017. it followed a concurrent triangulation strategy whereby quantitative and qualitative data were collected at the same time to permit comparison between the results obtained from each element[13]. this approach was selected to promote credibility by producing substantiated findings, and to shorten the data collection period within a congested professional sport setting. data collection occurred during a site visit to each of the 12 english premiership rugby clubs, during which eligible participants provided consent prior to completing two study questionnaires and a semi-structured interview. ethical approval was granted by the research ethics approval committee for health at the university of bath (ep 15/16 255). heads of medical services and heads strength & conditioning (s&c) coaches from each club were purposively targeted for recruitment as they would be best placed to comment on club-level approaches to player management; however, to promote equitable opportunity to take part in the research, all staff in the medical services and s&c departments were invited to participate. eligibility criteria were: (1) a member of the medical or s&c department at a premiership club; (2) directly involved in player management; (3) conversant in english. clubs were contacted directly via email and/or telephone (author mc) to initiate recruitment. a 12-item demographic questionnaire was used to collect participant characteristics (i.e. club role and professional experience level). a 15-item ‘general practices’ questionnaire captured current club practices and practitioner beliefs about injury risk on artificial turf using tick boxes and 7-point likert scales. both questionnaires were created for this study (author cm) based on instruments used to capture behaviours and beliefs in previous sports research[12]. these were face validated by the authorship team prior to use (supplementary online content). one researcher (cm) developed an interview topic guide to steer the interview dialogue, whilst allowing participants to say as much as they wished (supplementary content). this focused on practices related to player management in the week leading up to, during, and in the week following a match played on artificial turf, and reflections on how/why these practices differed from those employed for natural grass. interviews were conducted one-on-one for participants from 10 clubs. for the other two clubs, changes to the team’s schedule for the day meant that the heads of medical services and s&c had to be interviewed together (e.g. two-on-one). interviews were audio recorded for transcription and lasted 15-35 minutes. quantitative analysis was conducted using stata [statacorp version 13, 2013]. artificial turf exposure was arbitrarily dichotomised to preserve club confidentiality: clubs were classified as ’low exposure’ if they spent less than 50% of their combined training and match time on artificial turf, or ’high exposure’ if ≥50%. differences in questionnaire responses between respondents from highversus low-exposure clubs were assessed descriptively, given the exploratory nature of the research questions and the limited validation of the questionnaires. a single investigator (cm), who is an experienced sport injury researcher but has no background in rugby union or any personal relationships with the clubs participating in the study, transcribed interview recordings verbatim and led the analysis process. participants reviewed their transcripts to ensure accuracy (e.g. verification) before data were organised in nvivo [qsr international pty ltd. version 11, 2015]. thematic analysis followed the steps outlined by braun and clarke[14]: transcripts were read several times for familiarisation and inductive semantic coding was used to identify patterns in the data. higher order themes were developed iteratively, following a recursive process of reviewing and defining emerging concepts[13]. to enhance rigour and trustworthiness, a second researcher (mc) independently coded 10% of the data to facilitate comparisons between coders, and all themes were reviewed for coherence. quantitative and qualitative data were integrated at the point of interpretation, allowing the authors to note areas of convergence within the findings to strengthen the knowledge claims of the study whilst exploring any lack of convergence that emerged (e.g. triangulation)[13]. results questionnaire outcomes participant characteristics are presented in table 1. all 12 premiership clubs were represented, including 13 medical staff (12 heads of medical services and one match-day doctor) and 10 head s&c coaches. eighteen questionnaires were completed (78%), representing 11 clubs. two head s&c coaches declined participation because of competing time commitments, and five questionnaires were not returned for undisclosed reasons. three clubs had artificial match pitches and 10 clubs had regular access to artificial training pitches. eleven respondents (61%) reported club-level plans for managing players for artificial turf. six (33%) indicated that surface type influenced player selection for matches at their club. participants from high-exposure clubs did not report managing players any original research 3 sajsm vol. 32 no. 1 2020 differently during training (3/6 respondents) than those from low-exposure clubs (10/12 respondents). they were less likely to modify player management during match play (0/6 vs. 5/12), or to adjust recovery following artificial turf exposure (2/6 vs. 9/12). questionnaire responses are summarised in figures 1 and 2. twelve participants (67%) thought clubs with regular artificial turf exposure had a competitive advantage, but only for matches played on artificial surfaces. most participants table 1. participant characteristics participant characteristics (n=23) median (range) age (years) 36 (31-57) experience in current role (years) 4 (1-13) tenure at current club (years) 2 (1-5) previous clubs (total number)* 1 (0-5) employment in professional rugby (years) 8 (1-18) * includes all previous professional/international clubs where the participant was previously employed, including those based in the uk and abroad. fig. 1. number of respondents reporting specific current practices with respect to artificial turf fig. 2. number of respondents endorsing reasons players might be managed differently with respect to artificial turf original research sajsm vol. 32 no. 1 2020 4 believed that, compared to natural grass, injury risk on artificial turf was slightly higher (median score 5/7, range 37). personal concern about managing players for artificial turf varied widely (median score 5/7, range 1-7). interview results from the interviews, three higher order themes emerged: (1) perceptions of surface qualities and characteristics, (2) player interactions with artificial turf, and (3) player management approaches for artificial turf. each theme comprised several sub-themes that reflected varied experiences across clubs and the professional opinions of individual participants (table 2; full thematic tree in supplementary content). in the first theme, perceptions of surface qualities and characteristics, participants shared their positive and negative opinions about various features of artificial turf and discussed its benefits and drawbacks in the professional rugby union context. in particular, they spoke about the polarising nature of artificial turf and concerns they had about switching between surface types in terms of injury risk and competitive (dis)advantages. theme two was player interactions with artificial turf, which highlighted athlete perceptions and preferences regarding surface types, and how these can influence complex individual and club-level decision-making around issues, such as player selection. finally, the theme of player management approaches for artificial turf included participants’ explanations of how surface type affects game preparation and recovery practices as part of their day-to-day roles at their clubs. this theme brought to light how uncertainties about training adaptations and injury risk can create challenges in daily decision-making for practitioners. perceptions of surface qualities in terms of perceptions of surface qualities and characteristics, opinions about artificial turf were polarised, ranging from extremely positive to extremely negative. those from clubs with artificial turf home match venues were complimentary, as were participants from some other clubs that used artificial turf training pitches. they cited the turf’s resilience to poor weather conditions, consistency when practicing technical skills, and cleanliness compared to grass pitches. participants also identified the potential for faster gameplay: ‘from the gps data we tend to see higher max velocity speeds… we do find that the metres/minute goes up.’ those who disliked artificial turf primarily raised concerns over increased injury risk, particularly when transitioning between surface types: ‘it’s not great, in my opinion, to be going from soft pitch to hard pitch, soft pitch to hard pitch. that’s when we tend to find we get guys pulling up with tight achilles, tight hamstrings, groin tightness...’ more than half of the participants (including those with and without artificial turf home venues) thought high-exposure clubs held a competitive advantage due to tactical experience and player adaptation to the training stimulus of the pitch. the remaining participants thought there was no advantage, indicating that grass pitches offered a challenge to clubs accustomed to artificial surfaces: ‘they play on artificial turf every other week so they have an advantage in terms of being used to the way the ball bounces, the feel of the field, 50% of the time. but they also have a disadvantage 50% of the time when they go away and play on other surfaces.’ player interactions with artificial turf with respect to player interactions with artificial turf, participants said that players tend to either love it or hate it. staff from high-exposure clubs suggested that after some initial hesitation, most players had grown to enjoy artificial turf because of an increased speed of play, greater surface consistency, and the cleanliness of the field. low-exposure clubs reported more variability in player perceptions, particularly amongst those with a history of injury: ‘if you’ve previously been hurt on an artificial pitch, then you blame the artificial pitch… you don’t hear anyone going, ‘i’ve been injured on grass, i don’t want to play on grass ever again, i’m just going to play on an artificial pitch.’ but you hear people that get hurt on an artificial pitch, and they’re straightaway going, ‘it’s the pitch, it’s the pitch.’ there was also discussion about players who had been advised not to play on artificial turf for medical reasons, with some participants indicating that this could affect player selection: ‘so, if we’re looking to sign somebody [and we have] an [artificial] training facility… i mean, if this player cannot train on that surface, and we’re saying he definitively cannot, then he cannot be here. so it does start to influence who you recruit into your organization.’ player management approaches when discussing player management approaches for artificial turf, several participants referenced formal management plans at their club, although these were more common amongst lowexposure clubs. they typically involved aspects of adjusted training, but the most common concern to emerge was uncertainty over periodisation and whether match preparation needed to be changed. amongst low-exposure clubs, half table 2. list of themes and subthemes themes subthemes perceptions of surface qualities and characteristics artificial turf polarises people transitioning between surface types is a problem some pitches are maintained better than others it may (or may not) give a competitive advantage player interactions with artificial turf players love it or hate it increased speed of play means better performance the surface type we train on might affect player selection player management approaches for artificial turf formal management plans at the club match preparation may (or may not) be adjusted recovery strategies may (or may not) be tailored is there a relationship between artificial turf and injury? challenges in daily decision-making original research 5 sajsm vol. 32 no. 1 2020 elected to train on artificial turf leading into games on that surface, whilst the others continued training on grass: ‘do you accumulate familiarity on it, or do you do nothing so you’re not accumulating work and just take your hit at the weekend? i’m not sure if we’re doing the right thing or not.’ most clubs adjusted recovery protocols following games on artificial pitches. several relied on markers of fatigue and training load to guide the extent of that adjustment on a per player basis alongside general squad-level training reductions up to 48 hours postgame. participants identified increased muscle soreness and fatigue as the chief complaints associated with artificial turf. these were attributed either to unfavourable interactions between studded footwear and the turf, increased ground reaction forces or the increased speed and intensity of gameplay. high-exposure clubs indicated that following an initial adaptation period, players no longer reported soreness or fatigue related to the turf. some clubs reported that training on soft, wet pitches resulted in more muscle soreness and fatigue, which was alleviated by training on artificial pitches. many participants wondered whether there is a strong relationship between artificial turf and injury. around half of them believed that artificial surfaces do contribute to injury risk, although some thought this was primarily applicable to players with a history of injury: ‘so we think, with a certain player group, we’ve got a good correlation that if we expose them to artificial turf, training or playing, that the likelihood of them getting injured is quite high.’ participants reported turf-related injuries including abrasions, ankle injuries (particularly syndesmosis sprains), tendinopathy, and lumbopelvic pain, though artificial turf was most commonly linked with overuse injuries. concern was expressed for players with a history of soft tissue injury, lower extremity tendinopathy, or joint compromise (e.g. previous injury resulting in a reduced capacity to accommodate training and playing load). most clubs took precautions against exposing affected players to high loads on artificial surfaces and often incorporated more intense recovery periods following exposure. considerable discussion focused on managing injured players through rehabilitation. with allowances for injury type, some medical staff favoured performing rehabilitation on artificial turf, believing it provides a consistent, clean surface for safety and re-acclimatises players to high training loads. others routinely avoided artificial turf exposure because of a perceived increase in re-injury risk. surface type also had the potential to influence return-to-sport decisions: ‘i have made clear recommendation to delay a return-to-play of a recovering athlete because of the surface they were returning to.’ overall, the interviews highlighted several challenges around developing management strategies, including tactical aspects (i.e. understanding how surface properties affect ball behaviour) and logistical issues (i.e. accessing artificial surfaces for training). participants spoke about how these concerns presented challenges to their daily decision-making, the most salient of which was balancing player welfare and performance within a context of competing priorities: ‘…at the end of the day, they are there to do a job, so we’ve still got to protect them from a medical point of view but, you know, we want to give the player the best opportunity to get on the field.’ participants also identified four areas where additional research was needed to inform their practice: periodising training on artificial turf, injury risk, long-term player health, and appropriate footwear choices for artificial surfaces. discussion this study is the first to show that surface type is sufficiently influential to warrant pre-planned player management strategies in premiership rugby, but most clubs had formal approaches based on medical and coach experience rather than evidence. the common belief was that switching between surfaces caused more fatigue and injury problems than consistently training on one surface type; however, not all reported practices aligned with this belief. high-exposure clubs trained predominantly on artificial turf because they believed it minimised training load changes and provided necessary environmental consistency for tactical development. it is unclear whether this provided physiological adaptations to artificial turf exposure, but staff at these clubs had lower perceptions of turf-related injury risk than their low-exposure counterparts and reported that players at their clubs made fewer fatigue-related complaints. conversely, half of the lowexposure clubs trained on artificial pitches prior to games on that surface (to gain tactical familiarity) and the other half trained on grass (to minimise fatigue) in the preceding week. both of these approaches enforce surface switching either in the week leading into or during a match, which is incongruent with reported injury risk concerns. notably, these participants all expressed uncertainty about which approach was best and identified this as a priority area for research. all participants from low-exposure clubs reported adjusting recovery following matches on artificial turf to account for elevated muscle soreness and fatigue. a study in professional football (n=13) found that a one-off exercise bout on artificial turf did not induce greater fatigue or delay physical recovery compared to natural grass amongst those who regularly played on artificial surfaces[15]. similarly, fletcher et al.16] found no difference in sustained muscle soreness between surface types in rugby league. these findings contradict evidence from england’s premiership; however, where williams et al.[7] measured slightly but consistently elevated self-reported muscle soreness in the four days following matches played on artificial pitches. although this study’s findings are based on complaints made to medics/coaches rather than measuring player perceptions directly, participants speculated that higher speeds of gameplay on artificial turf may account for the soreness that they observed in their teams. there is some evidence showing decreased initial acceleration contact times and shorter contact times during cutting manoeuvres on artificial surfaces compared to grass, which may be perceived as “faster gameplay”;[10] however, further investigation into the original research sajsm vol. 32 no. 1 2020 6 success of altered recovery paradigms is warranted to determine whether these practices reduce perceived fatigue/soreness or indeed promote positive physiological adaptations. team medics reported that acute injuries associated with artificial turf exposure typically occurred at the foot or ankle, whereas abrasions and overuse injuries were more common and often affected the knees, hips and lower back. this is consistent with injury surveillance outcomes in this population[8,9] but the interviews highlighted particular concerns around the management of players with a history of joint compromise or tendinopathy. although research into human-surface interactions on various surface types is emerging, practitioners are largely reliant on experience and athletes’ self-reported symptoms to guide management strategies. importantly, the interview responses confirmed that ’high risk’ players are often prophylactically managed to reduce artificial turf exposure and this may influence subsequent injury risk estimates. participants also suggested that turf type could affect returnto-play decisions and player selection. recently, a small study (n = 30) investigated athlete’s perceptions toward artificial turf and found that artificial turf has greater acceptability amongst professional rugby players than footballers[10]. the present study has confirmed that there are mixed perceptions amongst medical and s&c staff as well which, when combined with player beliefs about safety and performance, have the potential to affect artificial turf exposure. players who are prevented from returning from injury onto an artificial surface (or refuse to) could record a week or more of additional time loss, depending on how ’return-to-sport’ is defined and captured, leading to significantly overestimated injury severity and burden in large scale surveillance studies. overall, the mixed-methods design of the present study was a strength-based approach in providing insight into the rationale supporting current player management practices. however, due to the study’s cross-sectional nature, practice changes through the season were unaccounted for. moreover, the questionnaires were not fully validated prior to use and practitioner beliefs about injury risk may therefore have been underor over-reported due to response bias or measurement error. as the study was limited to medical and s&c staff, the results may not capture other club-level decisions that could affect injury risk and thus the authors’ understanding may be incomplete. this study’s participant sample is also unlikely to be representative of all rugby union clubs or individual practitioners working in professional rugby union, as these settings and roles are heterogeneous and constantly evolving. yet, this has provided a first insight into the predominant concerns of support staff at professional rugby clubs with respect to player management for different surface types and provides direction for future research. conclusion player management approaches with respect to artificial turf in english professional rugby union are widely varied and largely experiential. most significantly, there is evidence that players are in some cases being proactively managed to minimise artificial turf exposure, therefore potentially affecting injury risk and severity estimates. this has meaningful implications for injury surveillance strategies, medical and performance programmes, and player welfare initiatives. conflict of interest and source of funding: this study was jointly funded by the rugby football union (rfu), the rugby players association (rpa) and premiership rugby. mc is the research and rugby development manager at premiership rugby. sk is the medical services director at the rugby football union (rfu). author contributions: cdm, sk and kas contributed to the inception and design of the study. cdm and mc led the analysis and interpretation of the data. mc assisted with participant recruitment and writing the manuscript. sk assisted with writing the manuscript. all authors participated in drafting and critical revision of the manuscript and approved the final version for publication. references 1. balazs gc, pavey gj, brelin am, et al. risk of anterior cruciate ligament injury in athletes on synthetic playing surfaces: a systematic review. am j sports med 2015;43(7):1798-1804. 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[doi: 10.1136/bjsports-2014093543] [pmid: 24928848] 13. creswell jw. research design: qualitative, quantitative, and mixed methods approaches. 2nd ed. sage publications, inc: london, 2003:208-225. 14. braun v, clarke v. using thematic analysis in psychology. qual res psychol 2006;3(2):77-101. [doi: 10.1191/ 1478088706qp063oa] 15. nédélec m, mccall a, carling c, et al. physical performance and subjective ratings after a soccer-specific exercise simulation: comparison of natural grass versus artificial turf. j sports sci 2013;31(5):529-536. [doi: 10.1080/ 02640414.2012.738923][pmid: 23121440] 16. fletcher bd, twist c, haigh jd, et al.. season-long increases in perceived muscle soreness in professional rugby league players: role of player position, match characteristics and playing surface. j sports sci 2016;34(11):1067-1072. [doi: 10.1080/02640414.2015.1088166][pmid: 26368285] original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license effect of the 90-second ‘gear’ exercise programme on cardiometabolic risk factors in persons with an elevated risk of cardiovascular disease n rugbeer,1,2 bspsc (hons), mspsc; d constantinou,2 mbbch, mphil; g torres,2 msc med, phd 1 department of sport, rehabilitation and dental sciences, tshwane university of technology, pretoria, south africa 2 centre for exercise science and sports, school of therapeutic sciences, faculty of health sciences university of the witwatersrand, johannesburg, south africa corresponding author: n rugbeer (rugbeern@tut.ac.za) cardiovascular disease (cvd) is the leading cause of mortality worldwide. sedentary behaviour alters metabolic and cardiovascular biomarkers and increases the risk of cardiometabolic diseases. [1] exercise is a critical factor to improve cardiometabolic health. health benefits are associated with following at least 150 minutes of moderate physical activity or 75 minutes of vigorous physical activity per week.[2] furthermore, the prevention of weight gain is prominent when physical activity is performed at ≥ three metabolic equivalents for >150 minutes per week.[3] however, the optimal duration and intensity of exercise required to improve cardiometabolic health warrants further investigation in the current day and age of limited time and escalating work and family commitments. high-intensity interval training (hiit) has recently gained popularity as a time-efficient exercise intervention aimed at improving cardiometabolic health in different population groups. a randomised controlled trial reported that hiit (9x4 minute intervals at ∼90% peak oxygen consumption with three minutes rest) was superior at improving insulin sensitivity compared with moderate-intensity continuous exercise (mice) in overweight women.[4] a contemporary meta-analysis showed that hiit provided similar benefits to those undertaking mice for improving body composition and total cholesterol in overweight or obese adults.[5] thus research seems inconsistent concerning the optimal duration, intensity and type of exercise aimed at improving cardiometabolic health in overweight or obese adults. a meta-review of 33 systematic reviews reported that hiit improved some inflammatory markers, cardiac and vascular functions, blood glucose, glycaemic control, cardiorespiratory fitness, heart rate, weight and percentage body fat variables.[6] however, traditional hiit with repeated sprints may result in undue stress on the cardiovascular system.[7] a close investigation of high-intensity training reveals that it is not a time-efficient intervention considering the repeated highintensity bouts followed by rest intervals during the exercise session.[8] a brief bout of exercise during different periods of the day will drastically minimise the time commitment of training.[8] mind-body exercise interventions improve general mental and physical health due to the direct influence of the nervous system on immune and endocrine functions.[9] the ‘gear’ exercise programme uses visualisation to enable participants to cognitively construct the increase and decrease of gears in a car to represent an increase and decrease in speed and intensity before and during the exercise session. the ‘gear’ exercise programme is new and this is the first study to test the principles of this exercise programme. therefore, the current study aimed to investigate the effect of the novel ‘gear’ exercise programme on cardiometabolic risk factors in persons with an elevated risk of cardiovascular disease. background: high-intensity interval training has recently gained popularity at improving cardiometabolic health. however, a close investigation of high-intensity interval training reveals that the exercise duration is similar to moderate-intensity continuous exercise. objective: to compare the effect of the time-efficient ‘gear’ exercise programmes to traditional exercise on cardiometabolic risk factors in persons with an elevated risk of cardiovascular disease. methods: the study implemented a six-week, randomised controlled trial. the variables were low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, total cholesterol, glycated haemoglobin (hba1c), blood pressure and body composition. forty-eight participants completed the study. participants were randomly assigned to either the ‘gear’ exercise programme repeated at different times during the day (gep-dt): cycled for 90 seconds, repeated three times/day, for three days/week (n = 12); ‘gear’ exercise programme at one point in time (gep-ot): cycled for 90 seconds followed by 4 minutes and 30 seconds rest, repeated three times at one point in time, for three days/week (n = 14); 30 minutes of moderate-intensity continuous cycling repeated three days/week at 55-69% hrmax (n = 11); and the controls, who were encouraged not to exercise (n = 11). results: the 90-second gep-dt intervention reduced hba1c post six-weeks of training (md = ­0.1±0.4, % δ = -1.3%, d = ˗0.70). the gep-ot group decreased blood triglycerides with a large effect size (md = ­0.6±1.3, % δ = ˗31.9%, d = ˗0.83). conclusion: the novel 90-second ‘gear’ exercise programme moderately reduced hba1c and the 18-minute gep-ot lowered blood triglycerides. ‘gear’ exercise programmes will encourage future research in persons with non-communicable diseases, and it should be considered as a public health initiative to promote exercise in clinical, home and work environments. keywords: lipids, glycaemia, health promotion, cardiovascular health, public health s afr j sports med 2021;33:1-8. doi: 10.17159/2078-516x/2021/v33i1a8894 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a8894 https://orcid.org/0000-0002-3363-7695 https://orcid.org/0000-0003-4437-7240 https://orcid.org/0000-0002-0197-4718 original research sajsm vol. 33 no. 1 2021 2 methods study design the study implemented a randomised controlled pre-test and post-test exercise intervention study design. ethical considerations the study was conducted in accordance with the declaration of helsinki. ethical clearance was obtained from the university of the witwatersrand’s human research ethics committee (medical) (m170239) and tshwane university of technology’s research ethics committee (rec/2016/10/005). population/unit of analysis and sampling strategy staff from the university were invited to participate in the study voluntarily. participants were screened using a questionnaire to ensure that they met the inclusion criteria of the study. participants were included in the study if they were between 30 and 49 years old and had two or more risk factors for cvd, such as physical inactivity, were overweight or obese, elevated blood pressure and elevated lipid profile. the participants should not have had any signs and symptoms of cvd, such as chest pain, dyspnoea, syncope, orthopnoea, tachycardia, known heart murmurs and unusual fatigue with activities of daily living. a physician medically cleared the participants for participation in the study. using simple random sampling, participants were assigned to the following groups: ‘gear’ exercise programme repeated at different times during the day (gep-dt): cycled for 90 seconds, repeated three times/day, for three days/week (n = 12); ‘gear’ exercise programme at one point in time (gep-ot): cycled for 90 seconds followed by 4 minutes and 30 seconds rest, repeated three times at one point in time, for three days/week (n = 14); 30 minutes of moderate-intensity continuous cycling repeated three days/week at 55-69% hrmax (n = 11); and the controls, who were encouraged not to exercise (n = 11). few participants were unable to participate in the follow-up assessments due to work commitments, family responsibilities and orthopaedic injuries not related to the exercise interventions (fig.1). fortyeight participants completed the study (gep-dt = 14; gep-ot = 12; mice = 11; ctrl = 11). the exercise programmes did not result in adverse events (fig. 1). lipid profile a fasting lipid profile was measured using the cardiochek® pa metre (polymer technology systems, indianapolis, united states of america). the test was conducted after the participants had adhered to an eight-hour overnight fast and was performed according to standard manufacturer procedures. the a1cnow®+ (polymer technology systems, indianapolis, united states of america) was used to measure glycated haemoglobin (hba1c) using the standard manufacturer recommended procedure. blood pressure an appropriately sized blood pressure cuff (gold series ds66 trigger aneroids, welch allyn, united states) was used on the non-dominant arm to measure blood pressure using standardised techniques. blood pressure was measured twice on the non-dominate arm and the average measurement was documented. body composition international standards for anthropometric assessment (isak) guidelines were used to measure height (seca 213, hamburg, germany), body mass to the nearest 0.1 kg (tanita digital scale, model hd-319, tanita corporation, tokyo, japan), fig. 1. consort diagram. gep-ot, ‘gear’ exercise programme at one point in time; gep-dt, ‘gear’ exercise programme repeated at different times during the day; mice, moderate-intensity continuous exercise; ctrl, control group original research 3 sajsm vol. 33 no. 1 2021 body mass index, skinfolds (harpenden skinfold calliper, baty international, west sussex, united kingdom), and waist and hip circumferences. exercise programmes blood pressure and heart rate were documented before the commencement of the exercise session. the exercise session was conducted three times/week for six weeks on alternate days of the week. the mode of exercise was stationary cycling on a wattbike with the air resistance set at 1 to facilitate cycling speed (wattbike pro, woodway, germany). dietary and fluid intake were not controlled. the researcher (biokineticist) supervised all exercise sessions. the new proposed gep-dt and gep-ot integrates and stimulates the function of the mind and body during the exercise session using visualisation. the gep-dt commenced with a visualisation process. a car analogy was used to explain the exercise intervention. the participants were encouraged to visualise the increase and decrease of gears in a car to represent the increase and decrease of speed and intensity in the exercise intervention respectively. the speed and intensity at the different gears were mentally constructed. the gears remained constant on the bike. the participants increased the gears mindfully, relevant to their perceived increase in speed and intensity, which was self-paced, enabling them to be in control of the exercise session. once the visualisation process was completed, the participants commenced the gep-dt with a 30 second warmup (self-paced visualisation gear 2). participants then increased the intensity gradually over 30 seconds using the visualisation technique (visualisation gear 3 = 10 seconds, visualisation gear 4 = 10 seconds and visualisation gear 5 = 10 seconds). after reaching peak self-paced speed at visualisation gear 5, the participants reduced the speed by decreasing the intensity every 10 seconds for 30 seconds (visualisation gear 4 = 10 seconds, visualisation gear 3 = 10 seconds and visualisation gear 2 = 10 seconds). hence, participants geared up and down in a self-controlled manner, which acted as a stimulus for them to be mindful of the exercise session. the total duration of the gep-dt per session was 90 seconds. this exercise intervention was repeated three times a day, with a total time commitment of 4 minutes and 30 seconds per day (fig. 2). the gep-ot was similar to the gep-dt protocol; however, participants repeated three repetitions of the intervention at one point in time with a rest period of 4 minutes and 30 seconds per repetition. therefore, the total duration of the gep-ot was 18 minutes per session (fig. 2). participants in the mice group performed moderate-intensity continuous cycling for a total duration of 30 minutes at 55–69% of hrmax. the participants in the control group (ctrl) did not exercise and continued with their daily administrative and household tasks, which were low-intensity activities (<3 metabolic equivalents) (fig. 2). a demonstration of the ‘gear’ exercise programme can be viewed on the following link https://www.youtube.com/watch?v=kabkrg9ex94 statistical analysis data were analysed using spss statistics for windows, version 23.0 (spss inc., chicago, ill., usa). the study was powered to detect between-group differences using g*power version 3 (≥10 participants per group with an acquired physiological effect size of 0.25 at 𝛼 = 0.05). normality of data was analysed using the shapiro-wilk test, histograms and q-q plots. non-normal variables were log-transformed and thereafter the variables were included in the analysis. univariate analysis was conducted to determine baseline differences in age, fitness level and body weight between the subject groups. a paired samples t-test was used to determine intra-group differences in the fig. 2. exercise programmes. gep-ot, ‘gear’ exercise programme at one point in time; gep-dt, ‘gear’ exercise programme repeated at different times during the day; mice, moderate-intensity continuous exercise; ctrl, control group https://www.youtube.com/watch?v=kabkrg9ex94 original research sajsm vol. 33 no. 1 2021 4 exercise interventions. the repeated measures analysis of variance (anova) was used to compare intergroup differences. if interaction effects were observed, the bonferroni post hoc test was used to compare treatment effects between the various groups. effect size (d) was calculated to determine the clinical significance between the exercise groups and the control group. the effect size was classified according to small effect size (d ≥ 0.20), moderate effect size (d ≥ 0.5) and large effect size (d ≥ 0.8), respectively. the effect size was accepted as a true effect if the effect size confidence intervals did not cross both the positive and negative 0.20 thresholds. the effect size was considered to be unclear if this occurred. the level of significance was set at p<0.05. results the mean age of participants in the training groups was gepot = 37 years, gep-dt = 39 years, mice = 40 years and ctrl = 38 years. more women than men participated in the study. there was no significant difference of age, fitness level and body mass between the subject groups at baseline (table 1). the gep-dt group had the highest adherence rate (87%) and the shortest significant exercise time commitment of 4 minutes and 30 seconds compared with the gep-ot (18 minutes) and the mice group (30 minutes). there was a significant difference in kilocalories in all the exercise groups. the average kilocalorie expenditure in the mice group was 16 times that of the gep-dt. there was a significant difference in peak heart rate, average power, peak power, average power/body mass, peak power/body mass and cadence between the gepdt vs mice and the gep-ot vs mice. the gep-ot (129±13 bpm) had the highest peak exercise heart rate compared to mice and gep-dt groups. moreover, the gep-dt (110±9 bpm) had the highest average exercise heart rate compared to the other groups (table 2). there was a significant decrease in the mean diastolic blood pressure within the mice group (p = 0.01). the systolic blood pressure and body composition variables were insignificant with the subject groups (p>0.05) (table 3). there was a significant increase in glycated haemoglobin within the mice group (p = 0.01). the other metabolic variables showed insignificant differences within the subject groups (p>0.05) (table 4). the mice group demonstrated a large effect size for diastolic blood pressure when compared to the ctrl group, which showed a true large meaningful reduction in diastolic blood pressure post-training (md = -5.4±3.8, % δ = -6.8%, d = -0.81, d (95% ci): -1.68, 0.06). this group demonstrated a large effect size for percentage body fat compared to the ctrl group, which showed a true large meaningful reduction in percentage body fat post-training (md = ­0.7±2.1, % δ = -2.5, d = ˗0.83, d (95% ci): -1.70, 0.04) (table 5). table 1. demographic profile of participants variable gep-ot (n=14) gep-dt (n=12) mice (n=11) ctrl (n=11) p-value the ratio of women to men 11/3 12/0 8/3 9/2 n/a age (years) 37 ± 5 39 ± 7 40 ± 6 38 ± 5 0.68 body mass (kg) 79.9 ± 11.9 85.1 ± 23.4 83.2 ± 14.7 84.6 ± 17.9 0.87 vo2peak (ml·min-1·kg-1) 11.7 ± 3.8 11.7 ± 3.5 12.3 ± 4.1 10.1 ± 3.3 0.56 data are presented as mean ± standard deviation. n, number; n/a, not applicable; gep-ot, ‘gear’ exercise programme at one point in time; gep-dt, ‘gear’ exercise programme at different times during the day; mice, moderate-intensity continuous exercise; ctrl, control group; vo2peak, peak oxygen consumption; p-value, probability value table 2. training data of participants in the exercise intervention groups training variables gep-ot (n=14) gep-dt (n=12) mice (n=11) p-value adherence (%) 82 87 77 n/a time commitment (minutes) 18 4.5 30 0.001*#& average heart rate (bpm) 109 ± 10 110 ± 9 109 ± 5 0.24 average heart rate expressed as % of max heart rate 60 ± 5 61 ± 4 61 ± 3 0.35 peak heart rate (bpm) 129 ± 13 127 ± 12 120 ± 6 0.001*# peak heart rate expressed as % of max heart rate 71 ± 7 70 ± 6 67 ± 3 0.001*# average power (w) 62 ± 33 58 ± 23 31 ± 15 0.001*# peak power (w) 127 ± 68 117 ± 56 52 ± 28 0.001*# average power/body mass (w.kg-1) 0.76 ± 0.37 0.76 ± 0.55 0.38 ± 0.20 0.001*# peak power/body mass (w.kg-1) 1.58 ± 0.80 1.54 ± 0.88 0.62 ± 0.29 0.001*# kilocalories (kcal) 66.2 ± 9.5 9.3 ± 2.1 148.0 ± 27.5 0.001*#& cadence (rpm) 57 ± 13 54 ± 8 44 ± 10 0.001*# peak cadence (rpm) 75 ± 17 73 ± 8 52 ± 11 0.001*# data are presented as mean ± standard deviation. %, percentage; bpm, beats per minute; w, watts; w.kg1,watts/kilograms; kcal, kilocalories; rpm, revolutions per minute; gep-ot, ‘gear’ exercise programme at one point in time; gep-dt, ‘gear’ exercise programme repeated at different times during the day; mice, moderateintensity continuous exercise; na, not applicable; p-value, probability value. * significant difference between mice vs gep-dt (p<0.01). # significant difference between mice vs gep-ot (p<0.01). & significant difference between gep-ot vs gep-dt (p<0.01) original research 5 sajsm vol. 33 no. 1 2021 although the mice group showed a moderate effect size for body mass and body mass index, the confidence intervals crossed the lower positive threshold (0.20); therefore, the effect is unclear for body mass and body mass index in the mice group (table 5). furthermore, the effect is unclear for percentage body fat and body mass index in the gep-dt group (table 5). the 90-second gep-dt intervention reduced glycated haemoglobin post six weeks of training with a moderate effect size compared to the ctrl group, which showed a true moderate meaningful reduction in glycated haemoglobin post-training (md = -0.1±0.4, % δ = -1.3%, d = ˗0.70, d (95% ci): -1.55, 0.14) (table 6). this group demonstrated a large effect size for lowdensity lipoprotein cholesterol/high-density lipoprotein cholesterol, which showed a true large meaningful increase in low-density lipoprotein cholesterol/high-density lipoprotein cholesterol posttraining (md = 0.2±0.6, % δ = 8.2, d = 0.89, d (95% ci): table 3. intra-group comparisons of blood pressure and body composition measurements across the subject groups variables gep-ot (n=14) gep-dt (n=12) mice (n=11) ctrl (n=11) systolic bp (mmhg) pre-test 113.0 ± 13.1 111.0 ± 13.6 113.0 ± 12.0 110.0 ± 13.0 post-test 110.9 ± 11.5 108.0 ± 8.30 108.7 ± 12.3 105.2 ± 10.5 p-value 0.38 0.37 0.16 0.07 diastolic bp (mmhg) pre-test 79.1 ± 5.98 78.4 ± 7.33 80.0 ± 9.48 78.73 ± 6.50 post-test 77.3 ± 7.91 78.0 ± 6.38 74.6 ± 9.59 77.36 ± 6.86 p-value 0.34 0.84 0.00a 0.46 body mass (kg) pre-test 79.9 ± 12.0 85.1 ± 23.4 83.2 ± 14.7 84.6 ± 18.0 post-test 80.2 ± 11.6 85.6 ± 23.8 83.2 ± 14.2 85.5 ± 18.4 p-value 0.68 0.31 1.00 0.20 bmi (kg/m2) pre-test 29.5 ± 4.71 32.2 ± 9.80 31.0 ± 5.44 31.3 ± 5.09 post-test 29.8 ± 4.86 32.2 ± 9.59 31.0 ± 5.51 31.8 ± 5.52 p-value 0.31 0.93 0.99 0.08 waist circumference (cm) pre-test 90.6 ± 8.97 89.8 ± 19.1 93.7 ± 11.8 97.1 ± 12.8 post-test 88.4 ± 9.39 91.3 ± 14.4 91.5 ± 10.4 95.3 ± 10.9 p value 0.12 0.57 0.28 0.23 body fat (%) pre-test 27.3 ± 7.10 28.9 ± 6.21 27.9 ± 6.41 28.0 ± 4.93 post-test 27.7 ± 6.37 28.7 ± 5.48 27.2 ± 5.57 29.3 ± 6.65 p-value 0.65 0.78 0.28 0.14 data are presented as mean ± standard deviation. a, intra-group significance p<0.05; gep-ot, ‘gear’ exercise programme at one point in time; gep-dt, ‘gear’ exercise programme at different times during the day; mice, moderate-intensity continuous exercise; ctrl, control group; bp, blood pressure; bmi, body mass index table 4. intra-group comparisons of metabolic markers across the subject groups variables gep-ot gep-dt mice crtl total cholesterol (mmol/l) n 14 12 11 11 pre-test 3.91 ± 0.91 4.17 ± 0.89 4.46 ± 1.08 4.23 ± 1.00 post-test 3.86 ± 0.75 4.12 ± 1.20 4.33 ± 0.94 4.32 ± 1.04 p-value 0.88 0.78 0.43 0.76 hdl-c (mmol/l) n 14 12 11 11 pre-test 1.24 ± 0.35 1.26 ± 0.27 1.40 ± 0.37 1.15 ± 0.21 post-test 1.38 ± 0.36 1.27 ± 0.31 1.48 ± 0.49 1.23 ± 0.24 p-value 0.08 0.74 0.24 0.15 ldl-c (mmol/l) n 11 9 9 10 pre-test 2.03 ± 0.84 2.15 ± 0.0.55 2.31 ± 0.82 2.58 ± 0.82 post-test 1.91 ± 0.77 2.38 ± 1.10 2.13 ± 0.66 2.45 ± 0.85 p-value 0.69 0.42 0.41 0.60 triglycerides (mmol/l) n 14 12 9 10 pre-test 1.85 ± 1.38 1.84 ± 0.89 1.24 ± 0.59 1.37 ± 0.48 post-test 1.26 ± 0.49 2.04 ± 1.39 1.23 ± 0.49 1.72 ± 0.85 p-value 0.15 0.70 0.98 0.19 tc/hdl-c n 14 12 11 11 pre-test 3.37 ± 1.23 3.39 ± 0.84 3.32 ± 0.91 3.81 ± 1.12 post-test 2.94 ± 0.79 3.32 ± 0.96 3.13 ± 0.94 3.58 ± 1.05 p-value 0.10 0.46 0.20 0.10 ldl-c/hdl-c n 11 9 9 10 pre-test 1.82 ± 0.97 1.84 ± 0.55 1.86 ± 0.79 2.36 ± 0.88 post-test 1.57 ± 0.74 1.99 ± 0.83 1.68 ± 0.86 2.02 ± 0.81 p-value 0.43 0.49 0.36 0.06 non-hdl-c (mmol/l) n 14 12 11 11 pre-test 2.67 ± 0.91 2.90 ± 0.81 3.06 ± 1.02 3.09 ± 0.99 post-test 2.48 ± 0.73 2.85 ± 1.10 2.85 ± 0.87 3.02 ± 1.06 p-value 0.47 0.75 0.15 0.82 fasting glucose (mmol/l) n 14 12 11 11 pre-test 5.07 ± 0.60 4.86 ± 0.60 5.16 ± 0.76 5.02 ± 0.43 post-test 4.92 ± 0.48 4.89 ± 0.54 5.28 ± 0.46 5.05 ± 0.34 p-value 0.27 0.84 0.55 0.76 hba1c (%) n 14 12 11 11 pre-test 5.90 ± 0.40 6.02 ± 0.34 5.78 ± 0.28 5.93 ± 0.31 post-test 6.01 ± 0.46 5.94 ± 0.36 5.97 ± 0.26 6.10 ± 0.44 p-value 0.26 0.49 0.00a 0.12 data are presented as mean ± standard deviation. a, intra-group significance p<0.05; n, number of participants; gep-ot, ‘gear’ exercise programme at one point in time; gepdt, ‘gear’ exercise programme at different times during the day; mice, moderateintensity continuous exercise; ctrl, control group; hdl-c, high-density lipoprotein cholesterol; ldl-c, low-density lipoprotein cholesterol; tc/hdl-c, total cholesterol/high-density lipoprotein cholesterol; ldl-c/hdl-c, low-density lipoprotein cholesterol/high-density lipoprotein cholesterol; non-hdl-c, non-high-density lipoprotein cholesterol; hba1c, glycated haemoglobin original research sajsm vol. 33 no. 1 2021 6 -0.05, 1.84) (table 6). the gep-ot group demonstrated a decrease in triglycerides post-training with a large effect size when compared to the ctrl group, which showed a true large meaningful reduction in triglycerides post training (md = ­0.6±1.3, % δ = ˗31.9%, d = ˗0.83, d (95% ci): -1.68, 0.01) (table 6). although the mice group showed a moderate effect size for triglycerides, the confidence intervals crossed the lower positive threshold (0.20); therefore, the effect is unclear for triglycerides in the mice group (table 6). analysis of covariance showed no significant group x time interactions on blood pressure, body composition and metabolic markers post six weeks of exercise in persons with an elevated risk of cardiovascular disease (p>0.05) (tables 5 and 6). discussion the primary finding of the study was that the 90-second gep-dt intervention moderately decreased hba1c in comparison to the ctrl group. the participants in the gep-dt significantly expended fewer calories compared to the other exercise groups, which suggests that the benefits derived from the gep-dt intervention are less reliant on calories expended during the exercise session. there was no significant difference in age, fitness level and body mass between the groups at baseline, which did not influence the effect of the exercise interventions. glycated haemoglobin is the gold standard to measure glycaemic control,[10] and an absolute change of 1% reduction in hba1c is associated with 37% reduction in microvascular complications, 21% reduction in diabetesrelated mortality and 14% of myocardial infarction.[11] furthermore, an absolute decrease of ≥0.3% in hba1c is considered a clinically meaningful value by the european medicine agencies.[12] the study showed a clinically significant moderate effect at a comparatively lower absolute change of 0.1%. however, this was achieved at a lower exercise volume compared to traditional models of training. diet could have influenced the hba1c result because the study did not control the carbohydrate intake. a systematic review and meta-analysis investigating the effects of familiar mice and hiit protocols revealed no significant differences in lipid profiles between the groups.[13] the current study concurs with the finding of this review; however, the novel finding is that the new gep-ot lowered triglyceride levels in persons with an elevated risk of cardiovascular disease with a large effect size irrespective of the insignificant probability value between the respective groups due to the small sample size. non-high-density lipoprotein cholesterol and elevated triglycerides are crucial mediators for residual atherosclerotic cardiovascular disease risk.[14] thus, the gep-ot group demonstrated a large decrease in effect size for triglycerides post six weeks of training, which provides an atheroprotective and cardioprotective effect in persons with an elevated risk of cardiovascular disease. although the 90-second gep-dt raised the lowdensity lipoprotein cholesterol/high-density lipoprotein cholesterol, a study indicated that enhancing the function rather than increasing the levels of high-density lipoprotein cholesterol is associated with a clinical effect in lowering the risk of cvd.[15] moderate-intensity continuous exercise significantly decreased diastolic blood pressure (dbp). an international korean longitudinal study revealed a j-shaped relationship relevant to dbp in the general population.[16] the korean study suggested that the general population is at risk of all-cause mortality with a dbp of <60 mmhg.[16] the reason for this finding is that coronary perfusion occurs during diastole. table 5. inter-group comparisons of blood pressure and body composition measurements across the subject groups variables gep-ot gep-dt mice crtl p-value (gxt) systolic bp (mmhg) δ score -2.1 ± 8.9 -3.0 ± 11.2 -4.3 ± 9.4 -4.8 ± 8.0 0.89 % δ -1.9 -2.7 -3.8 -4.4 d (95% c.i.) 0.32 (-0.48, 1.11) 0.18 (-0.64, 1.00) 0.06 (-0.78, 0.89) n/a diastolic bp (mmhg) δ score -1.8 ± 6.7 -0.4 ± 6.9 -5.4 ± 3.8 ˗1.4 ± 5.9 0.24 % δ -2.3 -0.5 -6.8 -1.7 d (95% c.i.) ˗0.07 (-0.86, 0.72) 0.15 (-0.67, 0.97) ˗0.81c (-1.68, 0.06) n/a body mass (kg) δ score 0.3 ± 2.5 0.5 ± 1.7 0.0 ± 1.5 0.9 ± 2.0 0.86 % δ 0.4 0.6 0.0 1.1 d (95% c.i.) -0.26 (-1.05, 0.53) -0.22 (-1.04, 0.60) -0.51 (-1.36, 0.34) n/a bmi (kg/m2) δ score 0.3 ± 1.1 0.0 ± 0.9 0.0 ± 0.6 0.5 ± 0.9 0.49 % δ 1.0 0.0 0.0 1.6 d (95% c.i.) -0.20 (-0.99, 0.60) 0.56 (-1.39, 0.28) -0.65 (-1.51, 0.20) n/a waist circumference (cm) δ score -2.2 ± 5.1 1.5 ± 8.4 -2.2 ± 6.6 -1.8 ± 4.7 0.42 % δ -2.4 1.7 -2.4 -1.9 d (95% c.i.) ˗0.08 (-0.87, 0.71) 0.48 (-0.35, 1.31) ˗0.07 (-0.91, 0.77) n/a body fat (%) δ score 0.4 ± 2.7 -0.2 ± 2.8 -0.7 ± 2.1 1.3 ± 2.7 0.31 % δ 1.5 -0.7 -2.5 4.6 d (95% c.i.) -0.33 (-1.13, 0.46) ˗0.55 (-1.38, 0.29) ˗0.83 c (-1.70, 0.04) n/a δ score, mean difference ± standard deviation of mean difference (absolute change score); % δ, relative percent change from baseline (relative change score); p-value (gxt), the interaction probability value between the subject groups and time from the repeated measures analysis of variance; d (95% c.i.), effect size (95% confidence interval of effect size); c, large effect size (compared to the control group); n/a, not applicable; gep-ot, ‘gear’ exercise programme at one point in time; gep-dt, ‘gear’ exercise programme at different times during the day; mice, moderate-intensity continuous exercise; ctrl, control group; bp, blood pressure; bmi, body mass index original research 7 sajsm vol. 33 no. 1 2021 coronary blood flow to the myocardium is hindered when dbp is <60 mmhg. moderate-intensity continuous exercise decreased dbp in the current study; however, the participants’ mean dbp postexercise was >60 mmhg, which had a cardioprotective effect in this group of participants. mice reduced % body fat with a large effect size. this finding concurs with a pilot randomised controlled trial showing a reduced body fat and body weight after engaging in light-intensity training. [17] moderate-intensity continuous exercise releases non-esterified fatty acids and oxidises free fatty acids. this increases the capacity of the muscle to take up non-esterified fatty acids by enhancing the requirement and number of capillaries, which stimulates the mobilisation of abdominal adipose tissue non-esterified fatty acids and decreases the risk of cardiovascular disease. [18] limitations more women than men participated in this study, and the study did not account for the potential effect of the different phases of the menstrual cycle. the study also did not control nutrition status. the control group’s activities were selfreported and not objectively measured. moreover, the study had a small sample size because it was powered from traditional highintensity programmes. conclusion the novel 90-second ‘gear’ exercise programme moderately reduced hba1c and the 18minute gep-ot lowered blood triglycerides. moderate-intensity continuous exercise decreased diastolic blood pressure and % body fat. the ‘gear’ exercise programmes will encourage future research in persons with non-communicable diseases and should be considered as a public health initiative to promote exercise in clinical, home and work environments. table 6. inter-group comparisons of metabolic markers across the subject groups variables gep-ot gep-dt mice crtl p-value (txg) total cholesterol (mmol/l) δ score -0.1 ± 1.0 -0.1 ± 0.6 -0.1 ± 0.5 0.1 ± 1.0 0.94 % δ -1.3 -1.2 -2.9 2.1 d (95% c.i.) ˗0.14 (-0.93, 0.65) ˗0.17 (-0.99, 0.65) ˗0.28 (-1.12, 0.56) n/a hdl-c (mmol/l) δ score 0.1 ± 0.3 0.0 ± 0.1 0.1 ± 0.2 0.1 ± 0.2 0.28 % δ 11. 0.8 5.7 7.0 d (95% c.i.) 0.23 (-0.56, 1.02) -0.43 (-1.26, 0.40) 0.00 (-0.84, 0.84) n/a ldl-c (mmol/l) δ score -0.1 ± 1.1 0.2 ± 0.8 -0.2 ± 0.6 -0.1 ± 0.8 0.69 % δ -5.9 10.7 -7.8 -5.0 d (95% c.i.) 0.01 (-0.85, 0.87) 0.45 (-0.46, 1.36) ˗0.07 (-0.97, 0.83) n/a triglycerides (mmol/l) δ score -0.6 ± 1.3 0.2 ± 1.6 ˗0.0 ± 0.6 0.4 ± 0.8 0.44 % δ ˗31.9 10.9 ˗0.8 25.5 d (95% c.i.) ˗0.83c (-1.68, 0.01) -0.11 (-0.95, 0.73) ˗0.50 (-1.42, 0.41) n/a tc/hdlc δ score -0.4 ± 0.9 -0.1 ± 0.3 -0.2 ± 0.5 ˗0.2 ± 0.4 0.63 % δ -12.8 -2.1 -5.7 -6.04 d (95% c.i.) ˗0.28 (-1.07, 0.52) 0.43 (-0.40, 1.26) 0.09 (-0.75, 0.92) n/a ldl-c/hdl-c δ score -0.3 ± 1.0 0.2 ± 0.6 -0.2 ± 0.5 -0.3 ± 0.5 0.73 % δ -13.7 8.2 -9.7 -14.4 d (95% c.i.) 0.11 (-0.74, 0.97) 0.89 c (-0.05, 1.84) 0.32 (-0.59, 1.23) n/a non-hdl-c (mmol/l) δ score -0.2 ± 0.9 -0.1 ± 0.6 -0.2 ± 0.5 -0.1 ± 0.9 0.99 % δ ˗7.1 ˗1.7 -6.9 -2.3 d (95% c.i.) ˗0.13 (-0.92, 0.66) 0.03 (-0.79, 0.85) ˗0.19 (-1.03, 0.65) n/a fasting glucose (mmol/l) δ score -0.2 ± 0.5 0.0 ± 0.4 0.1 ± 0.7 0.0 ± 0.3 0.55 % δ -3. 0.6 2.3 0.6 d (95% c.i.) ˗0.42 (-1.22, 0.37) 0.00 (-0.82, 0.82) 0.18 (-0.66, 1.01) n/a hba1c (%) δ score 0.1 ± 0.4 ˗0.1 ± 0.4 0.2 ± 0.1 0.2 ± 0.3 0.18 % δ 1.9 -1.3 3.3 2.9 d (95% c.i.) -0.17 (-0.96, 0.62) ˗0.70b (-1.55, 0.14) 0.09 (-0.75, 0.93) n/a δ score, mean difference ± standard deviation of mean difference (absolute change score); % δ, relative percent change from baseline (relative change score); p-value (gxt), the interaction probability value between the subject groups and time from the repeated measures analysis of variance; d (95% c.i.), effect size (95% confidence interval of effect size); b, moderate effect size (compared to the control group); c, large effect size (compared to the control group); n/a, not applicable; gep-ot, ‘gear’ exercise programme at one point in time; gep-dt, ‘gear’ exercise programme at different times during the day; mice, moderate-intensity continuous exercise; ctrl, control group; hdl-c, high-density lipoprotein cholesterol; ldl-c, low-density lipoprotein cholesterol; tc/hdl-c, total cholesterol/high-density lipoprotein cholesterol; ldl-c/hdl-c, low-density lipoprotein cholesterol/high-density lipoprotein cholesterol; non-hdl-c, non-high-density lipoprotein cholesterol; hba1c, glycated haemoglobin original research sajsm vol. 33 no. 1 2021 8 conflict of interest and source of funding: the authors declare that they have no conflict of interest. this work is based on the research supported in part by the tshwane university of technology (tut), south africa, through the department of higher education and training research development grant. acknowledgements: the authors appreciate the time and effort of all participants who took part in the study. the authors would like to acknowledge the assistance of dr lichaba for medically screening the participants, dr ajith for postgraduate support and dr maposa for statistical advice. professor mckune is thanked for advice on effect size calculations. the authors’ thanks are extended to pentasystems (pty) ltd for servicing and calibrating the wattbike pro. the authors are grateful to tshwane university of technology (tut), south africa, through the department of higher education and training research development for funding the research study. author contributions: nr was the primary researcher. all authors were involved in the study design and review process. references 1. thosar ss, bielko sl, mather kj, et al. effect of prolonged sitting and breaks in sitting time on endothelial function. med sci sports exerc 2015;47(4):843-849. [doi:10.1249/mss.0000000000000479][pmid: 25137367] 2. bouchard c, blair sn, katzmarzyk pt. less sitting, more physical activity, or higher fitness? mayo clin proc 2015;90(11):1533-1540. [doi:10.1016/j.mayocp.2015.08.005] [pmid: 26422244] 3. jakicic jm, powell ke, campbell ww, et al. physical activity and the prevention of weight gain in adults: a systematic review. med sci sports exerc 2019;51(6):1262-1269. [doi:10.1249/mss.0000000000001938]pmid: 31095083] 4. sun s, zhang h, kong z, et al. twelve weeks of low volume sprint interval training improves cardio-metabolic health outcomes in overweight females. j sports sci 2019;37(11):12571264. [doi:10.1080/02640414.2018.1554615][pmid: 30563431] 5. su l, fu j, sun s, et al. effects of hiit and mict on cardiovascular risk factors in adults with overweight and/or obesity: a meta-analysis. plos one 2019;14(1):e0210644. 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[doi:10.7326/0003-4819-147-6-200709180-00005][pmid: 17876019] 12. committee for medicinal products for human use, european medicines agency guideline on clinical investigation of medicinal products in the treatment or prevention of diabetes mellitus: draft 1,. 2012. cpmp/ewp/1080/00 rev.1. available: https://www.ema.europa.eu/en/documents/scientific-guideline/ guideline-clinical-investigation-medicinal-products-treatmentprevention-diabetes-mellitus-revision_en.pdf [accessed 18 october 2020]. 13. batacan rb jr, duncan mj, dalbo vj, et al. effects of highintensity interval training on cardiometabolic health: a systematic review and meta-analysis of intervention studies. br j sports med 2017;51(6):494-503. [doi:10.1136/bjsports-2015-095841] [pmid: 27797726] 14. ganda op, bhatt dl, mason rp, et al. unmet need for adjunctive dyslipidemia therapy in hypertriglyceridemia management. j am coll cardiol 2018;72(3):330-343. [doi:10.1016/j.jacc.2018.04.061] [pmid: 29935936] 15. ikenaga m, higaki y, saku k, et al. high-density lipoprotein mimetics: a therapeutic tool for atherosclerotic diseases. j atheroscler thromb 2016;23:385-394. [doi:10.5551/jat.33720] [pmid: 26830201] 16. kimm h, mok y, lee sj, et al. the j-curve between diastolic blood pressure and risk of all-cause and cardiovascular death. korean circ j 2018;48(1):36-47. [doi:10.4070/kcj.2017.0036] [pmid: 29322696] 17. chiu ch, ko mc, wu ls et al. benefits of different intensity of aerobic exercise in modulating body composition among obese young adults: a pilot randomized controlled trial. health qual life outcomes 2017;15(1):168. [doi: 10.1186/s12955-017-0743-4] [pmid: 28836987] 18. van hall g. the physiological regulation of skeletal muscle fatty acid supply and oxidation during moderate-intensity exercise. sports med 2015;45(1) suppl 1(suppl 1):s23-s32. [doi: 10.1007/s40279-015-0394-8] [pmid: 26553490] https://www.ema.europa.eu/en/documents/scientific-guideline/ volume 8 • number 1 • march 2001 the south african journal of sports medicine the official publication of the south african sports medicine association r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial exercise science and sports medicine resource centre ■ the contents o f the first edi­ tion o f the s outh a frica n jo u rn a l o f sports medicine for 2 0 0 1 reflect the m ulti-dis­ c ip lin a ry nature o f sports m e dicine. the stu d y by nurok and colleagues on the a th le tic a b ility o f young kenyan athletes reaches the conclusion that the superior running a b ility o f the k enyans can perhaps be explained by specific inheri­ ted characteristics. however, it is a difficult theory to prove and it is going to take m any more studies in disciplines rang­ ing from sociology to m olecular biology and genetics before we can conclude with confidence th a t factors governing suc­ cess in athletics are inherited. the study by w eston and her colleagues on heart rate as a m arker o f exercise intensity during m ini-tram poline exer­ cise contributes to the knowledge in the field o f applied exer­ cise physiology. t his study show s th a t the oxygen consum ption/heart rate relationship during m ini-tram poline exercise is not always linear. clearly, under these conditions heart rate is not an accurate m arker o f exercise intensity and therefore should be used with caution in prescribing exer­ cise. this study once again exposes the predicam ent that we have in the fields of sports m edicine and exercise physiolo­ gy. for exam ple, on the one hand we have devices fo r m ea­ suring heart rate which are highly sophisticated and can m easure heart rate under free living conditions with a high degree o f accuracy. furthermore, the heart rate data can be stored for several days before being transferred to a com ­ puter fo r analysis. on the other hand we have an emerging understanding of how heart rate changes during exercise under various conditions. we know that factors such as environm ental tem perature, state o f hydration, mode of exer­ cise, duration o f exercise and com petition all have a signifi­ cant effect on the heart rate/exercise intensity relationship. more recently it was shown that as physical fitness increases, maxim um heart rate decreases (zavorsky g s. evidence and possible m echanism s o f a ltered heart rate w ith endurance training and tapering. sports med 2000; 2 9 : 13 26.) this finding has important im plications in the health industry w here exercise participants are encouraged to monitor their training intensity according to their heart rate expressed as a percentage of maxim um heart rate. clearly if the decrease in m aximum heart rate with increasing fitness is not taken into account, then the relative intensity o f the training sessions will becom e harder and harder as fitness improves. in sum ­ mary, the study by w eston and her colleagues is important in that it contributes to narrowing the large gap between the technical capabilities of heart rate m onitors and the under­ standing of how heart rate responds to exercise. this gap has to be narrowed even further before heart rate monitors can be used to their full potential. the study by marino and booth addresses the question of w hether precooling before endurance exercise in moderate and high environm ental tem peratures has any ergogenic effect. research into this area is fascinating fo r two reasons. firstly, the underlying physiological mechanism s o f the 'pre­ cooling’ effect are not fully understood. secondly, the applied spin-offs of this research may result in m arathon race organ­ isers moving their jacuzzis to the start of the race rather than the end! the article on the popliteal vascular entrapm ent syn­ drome describes a possible cause of leg pain in young ath­ letes. this article points out that the syndrom e is more prevalent than previously believed and that a late diagnosis can have serious consequences for the patient. in contrast, an early diagnosis and surgical correction result in prompt and lasting relief of the symptoms. this article will surely contribute significantly to more clinicians making the correct diagnosis of the condition thus sparing their patients much discomfort, frustration and expense. identifying the com petitive edge in sport is always a pop­ ular topic. therefore the article on creatine supplem entation will be interesting fo r a wide range of readers. although the study in this journal focussed prim arily on the perform ance related effects, the side-effects that a large proportion o f the subjects experienced in this study should not go unnoticed. in summary, this edition of the journal should have something of interest to cater for the needs of all the health professionals and scientists who belong to a m ulti-discipli­ nary sports medicine association. this journal is a vehicle for new ideas in sports m edicine. you are encouraged to read it, enjoy it and hopefully learn som ething which can be used to improve perform ance and reduce the risk o f injury! mike lam bert e ditor-in-c hief sports medicine march 2001 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the south african journal of sports medicine volume 8 • number 1 • march 2001 edito r-in -c hief p rof m lam bert u niversity of c ape town senio r associate editor prof m mars u niversity o f natal edito rial board prof v coopoo university o f durban w estville dr k m yburgh university of stellenbosch p ro ft d noakes u niversity o f c ape town prof g rogers u niversity o f w itw atersrand p rof k vaughan u niversity o f c ape town pro du ctio n editor julia casciola sa medical association pro jects ma na ger w ayne press sa medical association pro du ctio n manager anne collins sa medical association pub lishing s a m edical association health and m edical publishing group 14 c entral square, pinelands 7405 private bag x1, pinelands 7430 tel (021) 531-3081, fax (021) 531-4126 repro & printing ince (pty) ltd contents editorial m lambert original research articles cardiovascular responses to self-paced running in warm humid conditions following whole-body precooling................ 3 f e marino, j booth does heart rate adequately reflect exercise intensity during mini-trampoline exercise?...................................................... 9 a r weston, a khan, m mars clustering of athletic ability in male kalenjin scholars......... 14 m nurok, a g morris, c o’connell, t d noakes popliteal vascular entrapment syndrome — a cause of leg pain to be considered in young athletes....................... 18 l j levien creatine supplementation and exercise performance in rugby players........................................................................ 26 r m n kohler letters to the editor drug-free sport..................................................................... 31 d bradbury, sa institute for drug-free sport early postural correction.......................................................32 a wenham instructions to contributors............................................ 33 the editor the s o u th a fric a n j o u r n a l o f s p o rts m e d ic in e p o b ox 115 n e w la n d s 7725 tel: 021 6 50 4561 fax: 021 6 8 6 7530 the views expressed in individual articles are the personal views of the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced w ithout the written consent o f the publishers. 2 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cardiovascular responses to self-paced running in warm humid conditions following whole-body precooling original research article frank e m arino1 (phd) john booth2 (phd) 'human movement studies unit and human performance laboratory, charles sturt university, bathurst, australia d e p a rtm e n t o f biomedical sciences, university o f wollongong, wollongong, australia abstract o bjective. this study exam ined the extent to w hich an ' attenuated cardiovascular strain during prolonged exer­ cise follow ing precooling m ight be attributed to changes in either plasma or blood volum e. design. seven subjects perform ed a 30-m inute self paced treadm ill run in w arm (32°c) humid (60% rela. tive hum idity) conditions following w hole-body precooling (pc) or no precooling (control (con)) in a , counterbalanced fashion. all subjects w ere m oderately , trained and had a mean peak pulm onary uptake ; ( v 0 2peak) o f 60.3 ± 2.4 m l/kg/m in/. blood sam ples w ere ; collected pre and post-exercise fo r the determ ination o f j haem oglobin (hb) and hem atocrit (hct). heart rate (hr), rectal tem perature (tre) and m ean skin tem pera­ ture (tsk) w ere monitored continuously during exercise. total body sweating (l/h) w as calculated from changes in nude body mass and corrected for fluid ingestion. results. the distance covered at the end o f con was 6 912 ± 345 m and increased following precooling to 7 263 + 389 m (p < 0.01). on com pletion o f the run con tre increased to 39.4 ± 0.4°c, w hile pc tre increased to 38.8 ± 0.4°c (p < 0.03). the end o f exer­ cise tsk w as 34.5 ± 0.6°c and 35.6 ± 0.5°c (p < 0.01) for pc and con, respectively. the hr response w as low er (p < 0.05) for pc a t 5 m inutes of exercise but not 1 fo r the rem ainder o f the run. the changes in hb and hct resulted in percentage changes in plasma volum e correspondence: frank e marino human perform ance laboratory human m ovem ent studies unit charles s turt university bathurst nsw, 2795 australia tel: 61 2 63 384268 fax: 61 2 63 384065 e-mail: fm arino@ csu.edu.au . (% apv) o f -6 .9 ± 3.6 fo r con and 3 . 0 ± 5.4 fo r pc, and percentage changes in blood volume (% abv) of -3 .4 ± 1.2 fo r con and -1 .8 ± 4.1 for pc; these ; changes w ere not significantly different between condi­ tions. conclusions. although the subjects significantly increased their perform ance in warm humid conditions following precooling w ith an attenuated cardiovascular 1 strain, it is unlikely that changes in either plasma or i blood volum e contributed to the attenuated cardiovas­ cular strain. introduction w hen exercise is performed in a hot environm ent a severe strain on the cardiovascular system is observed . 1 this strain is usually reflected by the changes in heart rate (hr), stroke volum e (sv) and cardiac output (q ) . 1 753 these cardiovascu­ lar dynam ics change in order that a finite q satisfies the m etabolic dem ands o f the w orking muscle and that the skin is highly perfused in order fo r the body to deal with the accu­ mulating body heat. moreover, during exercise in the heat cardiovascular drift is exacerbated due to a substantially reduced cardiac filling and sv which require a higher hr in order to m aintain q. progressive dehydration as a consequence o f exercise, particularly in the heat, can have a significant effect on the cardiovascular system resulting in haemoconcentration and a reduction in blood volum e (bv ) . 8 a reduced bv has been shown to com prom ise the cutaneous circulation ,5 w hich dim inishes convective heat transfer from the body core to the skin. h aem oconcentration resulting from running exercise is w idely reported .10 however, variable responses have been shown w here some subjects displayed transient haem ocon­ centration w h ile others displayed tra n sie n t haem odilu tio n .3,1720 n evertheless, fortney e f a/.6 have shown that during 30 minutes o f exercise at 60% o f m aximum aerobic power, a 10% reduction in bv resulted in significantly greater heat storage and core tem perature (tc) w ith substantially reduced sv and q and an elevated hr compared with indi­ viduals w ith a m aintained bv. moreover, it is generally accepted that a greater loss o f plasma volum e (pv) is asso­ sports medicine march 2001 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:fmarino@csu.edu.au ciated with greater increases in tc, tachycardia and hypoten­ sion during exercise heat stress .14 this is particularly im por­ tant as a reduced pv has been shown to limit exercise in concert with decreased plasma osmolality, skin blood flow and sweating ra te .1924 in addition, sv is low er and hr higher in the early stages of exercise when pv is reduced following hypohydration .2227 therefore, m inim ising the therm al strain during exercise in the heat is extrem ely important for attenuating a d e crem ent in exercise perform ance and increasing the safety of exercise under more extrem e condi­ tions. several studies 12 1526 have shown the precooling strategy to be beneficial in enhancing endurance perform ance during moderate and high environm ental tem peratures. generally, these studies show cardiovascular and therm oregulatory strain to be reduced substantially during exercise following precooling. however, it is still unclear w hether precooling reduces cardiovascular strain during exercise heat stress as a consequence o f an attenuated reduction in either pv or bv. therefore, this study examined to w hat extent prolonged exercise perform ance m ight be im proved-following precool­ ing and w hether that im provem ent m ight be in part due to an attenuated cardiovascular strain. materials and methods •the therm oregulatory and perform ance aspects o f this study have been published in a com panion paper.2 subjects and experim ental design seven subjects (five men and tw o w om en) volunteered for the study. all w ere com petitive runners and apparently in good health as reported by a health history questionnaire and an exercise stress test. none of the subjects reported heat exposure within the preceding 2 months of the study. the mean (± sd) fo r age, mass, height, body surface area, peak pulm onary uptake ( v 0 2peak) and m axim um hr w ere 25 ± 4.5 years, 66.2 ± 9.5 kg, 171.0 + 8 . 8 cm, 1.76 ± 0.15 m2, 63.5 + 2.6 ml/kg/min, and 188 ± 7 beats/min, respectively. the experim ent w as approved by the ethics in human research com m ittee of charles sturt u niversity and all subjects gave w ritten inform ed consent. all participants refrained from vigorous exercise, caffeine and alcohol ingestion for at least 24 hours before reporting to the laboratory. during the initial visit the subjects w ere fam il­ iarised with treadm ill running, anthropom etric m easurem ents w ere recorded and a maximal incremental treadm ill test to exhaustion w as undertaken. v 0 2peak w as defined as the highest v 0 2 (m l/kg/m in) attained over a 1-m inute period.' the first subject w as random ly assigned to either a run in the heat (control (con)) or a run in the heat following w hole-body precooling (pc). all subsequent subjects were assigned in a counterbalanced fashion. the am bient tem ­ perature (ta) and relative hum idity (rh) w ere set at 32°c and 60% , respectively. testing was scheduled a t least 3 7 days apart but at the sam e tim e of day so th a t circadian variation could be minimised. on the day of testing participants reported to the laboratory and rested quietly for approxi­ m ately 2 0 minutes, after which a pre-exercise blood sample w as drawn and nude body mass measured. a rectal probe w as inserted and hr transm itter and skin therm istors secured. subjects then either com m enced their perfor­ mance run or were immersed in a w ater bath for w hole-body precooling as previously described .16 during the run sub­ je cts ingested a controlled volum e of distilled w ater in an attem pt to control for a progressive dehydration effect. once the run w as com pleted a post-exercise blood sam ple was drawn, subjects w ere tow elled dry and nude body mass was re-measured. precooling manouvre the method of w hole-body cooling has been previously described . 16 briefly, however, subjects reclined in a water bath to the level of the neck. the initial w ater tem perature was set at 28 29°c. a fter an accom m odation period water was siphoned and replaced with cold w ater (approxim ately 13°c) until w ater tem perature reached 23 24°c. the immersion protocol lasted fo r 60 minutes or until continuous shivering w as observed. o nce subjects left the w ater bath they were towelled dry, prepared for exercise, and com ­ menced running within 3 minutes. perform ance run the subjects ran on a motorised treadm ill. the speed was set by the experim enter to the nearest 0.5 km/h and increased or decreased on dem and through previously rehearsed signals. the aim of the test was for subjects to run as great a distance as possible w ithin the allotted 30 m in­ utes. on com pletion of the run the total distance travelled was recorded. during and following the run participants were not given any feedback regarding their performance other than the self-selection of running speed. therm oregulatory m easurem ents and calculations rectal tem perature ( t j was monitored and measured with a 12-gauge rectal th e rm is to r (m on-a-therm , m a llin ckro d t medical inc., st. louis, mo) inserted 10 cm beyond the anal sphincter. skin tem perature (tsk) w as measured at four sites (chest, arm, thigh and calf) with therm istors (427 series, yellow springs instrument, oh) secured with transpore tape. all therm istors were connected to an eight-channel telether­ m om eter (zentem p 5000, zencor, australia). temperatures w ere monitored continuously and recorded pre-exercise and at the end o f exercise. mean skin tem perature (tsk) w as cal­ culated using the area weighted form ula25: tsk = 0.3 ( t ^ + tarm) + 0.2 (t,high + tleg). heat storage (s) w as calculated from tsk and tre using the formula15: s = 0.97 . m . a tb. a ^ , where tb = (tre .,0.65) + (tsk . 0.35), 0.97 is specific heat of body tis­ sue (w/kg), m is body mass (kg) and ao"1 is surface area (m2). body mass, fluid intake and total body sweating c hange in nude body mass was measured to the nearest 10 g on an electronic precision balance (hw 100kai, gec, avery ltd., australia). before com m encing the performance run a drink bottle w as filled w ith a known quantity of distilled 4 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) w ater (range 500 600 m l) so that subjects could drink ad libitum. in the subsequent trial subjects w ere only perm itted to drink a sim ilar volum e of w ater to that consum ed during the initial trial. a t the end of the trial the rem aining w ater vol­ ume w as subtracted from the initial w ater volum e and recorded. this value was also used to adjust the nude body m ass measurem ent. w ater volum e w as m easured to the nearest 1 ml using a graduated 1 0 0 ml cylinder. heart rate hr w as m onitored continuously and recorded pre-exercise, at 5-m inute intervals during exercise and a t the end of exer­ cise using a sports tester (polar electro, oy, finland). blood sampling, analysis and calculations pre and post-exercise blood sam ples w ere drawn from a superficial vein on the dorsal aspect o f the hand using a 2 1 gauge needle. the pre-exercise blood draw was obtained w hile subjects w ere seated. the post-exercise blood sam ­ ple was obtained within 2 m inutes of com pletion of exercise. in all cases the blood sam ples w ere collected while the sub­ je c t rem ained seated. blood w as collected in vacutainers containing edta for determ ination of haem oglobin (hb) and haem atocrit (hct). h aem atological variables w ere quantified using the c oulter principle with a c oulter ster analyser. the percentage changes in blood volum e (% abv) and plas­ ma volum e (%apv) w ere calculated using the following equations4: %abv = (h b,/h b 2 1 ) x 100 (equation 1); and % apv = (((hb,)x (1 hct2)/ (hb2) x (1 hct,)) 1 ) x 100 (equation 2); w here hb, and hct, are pre-exercise values and hb2 and hct2 are post-exercise values. 1 i statistics statistical analyses w ere perform ed using an spss for w indows (release 7.5.1) softw are package (spss inc., 1996). descriptive statistics were generated fo r all variables. s tudent’s paired f-tests w ere used to com pare pre and post­ exercise m easurem ents for w ithin treatm ents and between conditions. continuous m easurem ents such as hr w ere analysed using analysis of variance (anova) for repeated m easures on time. w hen significant main effects w ere detected tukey's hsd (honestly significant difference) post hoc procedure was employed to locate the source of signifi­ cance. statistical significance was set at p < 0.05. values are reported as mean + standard deviation (± sd). results running performance the distance covered at the end o f con w as 6 912 ± 345 m. this result was significantly im proved following precooling to 7 263 ± 389 m (p < 0.01). the running speeds at each 5 minute interval are shown in fig. 1. the running speeds w ere only different at 30 m inutes w hen subjects w ere able to accelerate from 14.6 km/h in con to 16.8 km/h (p < 0.03) in pc. although the running speeds w ere only different at 30 minutes, participants w ere able to maintain a higher average 19 11 t fm e (m /n ) fig. 1. mean heart rate response and running speeds at pre exercise (0 minutes), 5-minute intervals and end-exercise (30 minutes) for control and precool conditions. *p < 0.05 com­ pared with precool. running speed throughout pc at 15.1 + 1.5 km/h compared with 14.3 ± 1.5 km/h (p < 0.01) for con. therm oregulatory responses w hile the pre-exercise tre fo r con was 37.4 + 0.1 °c, w hole body precooling reduced pre-exercise tra from 37.3 ± 0.1 °c to 36.6 ± 0.6°c (p < 0.0001) so th a t precooled subjects start­ ed the exercise bout with a significantly reduced t,e. on com pletion o f the run con tre increased to 39.4 ± 0.4°c, while during pc tre increased to 38.8 ± 0.4°c (p < 0.03, fig. 2). precooling reduced the pre-exercise tsk from 34.1 ± 0.20°c to 28.8 ± 1.6°c (p < 0.0001), w hile the pre-exercise tsk for con was 34.4 + 0.28°c. the end of exercise tsk was 34.5 ± 0,6°c and 35.6 + 0.5°c (p < 0.01) for pc and con, respectively (fig. 2). the end o f exercise heat storage increased from 62.8 ± 12 w /m 2 fo r con to 124 ± 23 w /m 2 for pc (p < 0.05). body mass and total body sweating responses the pre-exercise values fo r nude body m ass w ere 63.8 + 3,1 kg and 63.9 ± 3 .1 kg (p = 0.34) for con and pc, respec­ tively. the end o f exercise body mass was adjusted for w ater ingestion and was 63.0 ± 3.0 kg fo r con and 63.1 ± 2.9 kg (p = 0.76) for pc. the change in body m ass for both trials w as 0 . 8 kg am ounting to an equal and total body sweating of 1 . 6 l/h. sports medicine march 2001 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 40 35 measurement time fig. 2. mean changes in rectal and mean skin temperatures at pre-exercise and end-exercise.*p < 0.01 compared with precool condition. preversus end-exercise values are all significantly different. heart rate response the hrs at 5-m inute intervals are shown in fig. 1. resting hr following w hole-body precooling was reduced from 75 ± 3 beats/min to 62 ± 4 beats/m in (p < 0.05). the hr at 5 m in­ utes was significantly (p < 0.05) lower a t 158 ± 10 for pc com pared with 166 ± 10 beats/m in for con, after which it w as not different fo r the rem ainder o f the run between con­ ditions. the end-exercise hrs w ere sim ilar for con (189 ± 4 beats/min) and pc (190 ± 4 beats/min). haem atological responses the hb and hct values are given in table i. pre-exercise hb values w ere sim ilar fo r both con and pc. on com pletion o f the run, hb concentrations w ere not significantly altered. the pre-exercise h ct values w ere also sim ilar for both trials. however, the end-exercise con hct increased significantly from 45 + 0.03% to 47 ± 0.03% (p = 0.006) com pared with 46 + 0.04% for pc. the percentage changes in bv and pv are given in table ii. the changes in hb concentration and hct did not significantly alter the % apv or % abv for either experim ental condition. tab le 1. mean (± sd) haem oglobin and haem atocrit values fo r pre and post-exercise (n = 7) con pc prep ost­ prep o st­ exerc ise exercise exercise exercise hb (g/dl) 15.3 ± 1 .2 15.8 ±1 .2 15.3 ± 1.5 15.6 ± 1.4 hct (%) 45 ± 0.03 4 7 ± 0.03* 46 ± 0.04 47 ± 0,04 ' p = 0 .0 0 6 com pared with c o n value. c o n = control trial, p c precooling trial. * table h. percentage changes fo r blood (bv) and plasm a volum e (pv) %abv (con) %abv (pc) %apv (con) %apv (pc) mean 3 . 4 -1 .8 6 . 9 3 .0 ±s d 1.2 4.1 3,6 5.4 c o n = control trial; p c = precool trial, % a = percentage change. discussion previous precooling studies have shown th a t endurance exercise either at a fixed % vozmax or during either self-paced running or cycling im proves exercise perform ance in m oder­ ate and warm , humid conditions .2 12,526 although traditional­ ly e n durance pe rfo rm a n ce has been evaluated using protocols at a fixed w orkload to exhaustion, it is now appar­ ent th a t the reliability of such protocols is questionable .18 in addition, it is now thought that self-paced or stochastic pro­ tocols are able to give a better representation of perfor­ m ance e n h a n ce m e n t b e cause o f p o te n tia lly hig h er reliability." therefore, in the present study a self-paced pro­ tocol was used in order to evaluate better the m agnitude of im provem ent in running perform ance, thereby evaluating the practical application of precooling. previous precooling studies21215 indicate th a t therm oregu­ latory and cardiovascular strain are attenuated as a result of the precooling manouvre. however, none of these studies report or exam ine to w hat extent the attenuated cardiovas­ cular strain following precooling is influenced by changes in bv or pv. the effects o f sm all alterations in bv and pv on circulatory dynam ics during exercise in a hot environm ent can be critical to perform ance. the dem ands placed on the circulatory system during exercise in the heat are partly due to an increased blood flow to the skin to facilitate the dissi­ pation o f heat. additionally, fluid is lost from the vascular com partm ent, w hich further com prom ises cardiac fillin g .21 in the present study, exercise endurance was enhanced following w hole-body precooling. this im provem ent was accom panied by a reduced therm oregulatory and cardiovas­ cular strain. the attenuated therm oregulatory strain result­ ing from precooling has been previously dealt w ith .1,12 briefly, however, it is clear th a t precooling enhances the capacity to store heat m ainly as a result o f the large reduction in skin tem perature .12 a larger capacity to store heat, coupled with the capacity for higher exercise intensity, would enable sub­ je cts to com plete more work. in fact, the subjects maintained a higher average running speed throughout the run following pc, and it was evident that the m ajority of gains in perfor­ 6 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mance w ere a result o f increasing running velocity toward the end o f the trial (25 30 m inutes). during the early stages o f exercise (0 5 minutes) hr w as significantly lower, after which it was not different. however, the observation that hr was not different between conditions for the rem ainder of the run ( 1 0 3 0 min) indicates that subjects w ere able to run at a higher intensity with a sim ilar hr, as evidenced by the higher average running speed and significantly greater dis­ tance achieved by the precooled subjects in the allotted 30 minutes. however, the end o f exercise hr was sim ilar for both conditions. it rem ains unclear w hy hr would be similar at the end o f exercise given the reduced therm oregulatory strain, increased capacity for heat storage and higher work output fo r subjects following precooling. this result indicates that subjects perform ed to their m axim um physiological capacity. it is also possible that subjects adopted a pacing strategy that was consistent with reduced cardiovascular and therm oregulatory demands. for instance, it has been suggested that during self-paced exercise, subjects are able to take advantage o f pacing rather than perform ing to an im posed o r fixed external w orkload which would allow the individual to com plete the activity with an attenuated physio­ lo g ica l stra in and reduce the likelihood o f prem ature fatigue . 13 during prolonged exercise in the heat, haem oconcentra­ tion can result as a consequence o f progressive dehydration9 and can ultim ately lead to a reduced bv com prom ising skin blood flow and reducing the am ount of convective heat trans­ fer from body core to skin. in the present study the % abv was -3 .4 % for con compared w ith 1 . 8 % for pc, although these values w ere not significantly different. the non-signif icant apv of -6 .9 % for con com pared with -3 .0 % for pc, indicates that precooling had very little effect on pv. as can be seen from table i, the percentage changes in pv are mainly a result o f the discrete change in hct, particularly for con w here the post-exercise hct was significantly elevated com pared with pc. this sm all change in hct was unable to augm ent significantly the %apv for con. fortney et al.6 have shown that a 10% reduction in bv can substantially increase the heat storage and tc during 30 m in­ utes o f cycling exercise at 60% v 0 2max in tfl of 35°c. our results show that bv was relatively unaffected as a result of exercise in the heat either with or w ithout w hole-body pre­ cooling. hence, it is difficult to attribute the attenuated car­ diovascular strain to either changes in bv or pv. there are several reasons why we do not find a significant attenuation in reductions o f either bv or pv. for instance, during both con and pc trials subjects ingested sim ilar volum es o f w ater w hich may have prevented a large, and gradual dehy­ dration. also, w hile adjusting the change in post-exercise body m ass for fluid intake, it was apparent that total body sw eating was sim ilar for both trials. however, what is not readily apparent is the greater absolute w ork rate of the sub­ je cts during pc compared with con. hence, although w ater ingestion was similar, the sw eat rate during pc was relative to the increased intensity of exercise. this indicates that car­ diovascular strain during exercise w as attenuated m ainly as a result o f a significantly reduced tsk possibly alleviating the need to increase cutaneous circulation for increased con­ vective heat transfer. o ther possible reasons for a reduced cardiovascular strain and increased perform ance following precooling m ight be an increased ru nning econom y. although not measured in the present study, oxygen con­ sum ption was m easured in tw o other sim ilar studies.212 in both these studies oxygen consumption, w as sim ilar for con­ trol and precooled subjects, and given the increased exer­ cise intensity either by higher running speeds2 or cycling speeds12 for a sim ilar m etabolic cost, it is quite possible that econom y of running in the present study w as increased fol­ lowing precooling. another difficulty relating to studies quantifying bv and pv changes during exercise is the possible effect of posture. it has long been recognised that posture has a confounding effect on bv.5 for instance, pre-exercise blood samples taken while seated may indeed result in different bv calcula­ tions if a subsequent sam ple is taken w hile standing.4 for this reason the blood sam ples w ere taken while subjects w ere seated during both pre and post-exercise. conclusion in conclusion, the results o f this study indicate that whole body precooling does not induce haem atological changes that could account in a significant w ay for an attenuated car­ diovascular strain during prolonged running exercise in warm, humid conditions. a lthough the benefits of precooling can in part be attributed to attenuated therm oregulatory and cardiovascular strain, it seems that the attenuated cardio­ vascular strain is prim arily a result of a reduced tc and tsk reducing the need for increased cutaneous circulation. r e f e r e n c e s 1. adams wc, fox rh, fry j, macdonald ic. thermoregulation during marathon running in cool, moderate, and hot environments. j a ppl physiol 1975; 38: 1030-7. 2. booth j, marino f, ward jj. improved running performance in hot humid conditions following precooling. m ed s ci sports exerc 1997; 2 9 : 943-9. 3. diaz fj, brandsford dr, kobayashi k, horvath sm, mcmurray rg. plasma volume changes during rest and exercise in different postures in a hot humid environment. j a ppl physiol 1979; 4 7 : 798-803. 4. dill db, costill dl. calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. j appl physiol 1974; 37: 247-8. 5. fawcett jk, wynn v. effects of posture on plasma volume and some blood constituents. j clin pathol 1960; 13: 304-10. 6. fortney sm, nadel er, wenger cb, bove jr. effect of acute alterations of blood volume on circulatory performance in humans. j appl physiol 1981; 50: 292-8. 7. galloway sdr, maughan rj. effects of ambient temperature on the capacity to perform prolonged cycle exercise in man. med sci sports exerc 1997; 29: 1240-9. 8. gonzalez-alonso j, mora-rodr(guez r, below pr, coyle ef. dehydration markedly impairs cardiovascular function in hyperthermic endurance ath­ letes during exercise. j a ppl physiol 1997; 82: 1229-36. 9. harrison mh, edwards rj, leitch dr. effect of exercise and thermal stress on plasma volume. j appl physiol 1975; 39: 925-31. 10. harrison m. effects of thermal stress and exercise on blood volume in humans. physiol rev 1986; 65:149-209. 11. jeukendrup a, saris hm, brauns f, kester adm. a new validated endurance performance test. med sci sports exerc 1996; 28: 266-70 12. kay d, taaffe dr, marino fe. the effect of whole-body precooling and heat storage during self-paced cycling performance in warm humid condi­ tions. j sports sci 1999; 18: 937-44. 13. kay d, marino fe, cannon j, st clair-gibson a, lambert ml, noakes td. evidence for neuromuscular fatigue during high intensity cycling in warm humid conditions. e ur j a ppl physiol (in press). 14. kenney wl, johnson jm. control of skin blood flow during exercise. med sci sports exerc 1992; 24: 303-12. 15. lee dt, haymes em. exercise duration and thermoregulatory responses after whole-body precooling. j a ppl physiol 1995; 79 : 1971-6. sports medicine march 2001 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 16. marino f, booth j. whole-body cooling by immersion in water at moderate temperatures. j s ci m ed sport 1998; 1(2): 12-21. 17. maron mb, horvath sm, wilkerson je. acute blood chemical alterations in response to marathon running. e u r j a ppl physiol 1975; 34: 173-181. 18. mclellan tm, cheung ss, jacobs i. variability of time to exhaustion dur­ ing submaximal exercise. can j a ppl physiol 1995; 20: 39-51. 19. montain sj, coyle ef. fluid ingestion during exercise increases skin blood flow independent of increases in blood volume. j appl physiol 1992; 73: 903-10. 20. myhre lg, hartung gh, tucker dm. plasma volume and blood metabo­ lites in middle-aged runners during a warm weather marathon. e ur j appl physiol 1982; 48: 237-40. 21. nadel er, cafarelli e, roberts mf, wenger cb. circulatory regulation dur­ ing exercise in different ambient temperatures. j appl physiol 1979; 46: 430-7. 22. nadel er, fortney sm, wenger cb. effect of hydration state on circula­ tory and thermal regulation. j appl physiol 1980; 4fj: 715-21. 23. nielsen b, hales jrs, strange s, christensen nj, warberg j, saltin b. human circulatory and thermoregulatory adaptations with heat acclama­ tion and exercise in a hot, dry environment. j physiol 1993; 460: 467-85. 24. nose h, mack gw, shi x, morimoto k, nadel er. effect of saline infusion during exercise on thermal and circulatory regulations. j appl physiol 1990; 69: 609-16. 25. ramanathan ln. a new weighting system for mean surface temperature of the human body. j appl physiol 1964; 19: 531-3. 26. schmidt v, briick k. effect of a precooling maneuver on body temperature and exercise performance. j appl physiol 1981; 50 : 772-8. 27. senay lc jun. temperature regulation and hypohydration: a singular view. j a ppl physiol 1979; 47 : 1-7. now more important than ever! can you take it? do you know? drugsportfolio 2000 for sport in south africa 2/e compiled and edited by marlize smuts, m pharm published by infosource cc foreword by sam ramsamy, president of nocsa an essential working reference of up-to-date inform ation on prohibited and permitted substances for sportsm en in south africa. “i found it to be complete, easily accessible and user friendly and it quickly provides the answers to the questions asked of me.’’ prof. wayne derman, president of the sa sports medicine association what does this publication contain? explanatory notes; anti-doping information, the international olympic committee anti-doping code, 1 january 2000; accredited laboratories; doping general information; 13 steps in drug testing; listing of prohibited, restricted and permitted drugs; pharmacological classification of prohibited and permitted substances; pharmaceutical and health companies. who should have this reference work? all medical practitioners, pharmacists, sports administration institutions, coaches, relevant libraries and research institutions. order information [ ] cd-rom, june 2000, isbn 1-919770-19-4 price r185.00 (incl. vat) carriage r17.50 for 1st copy, r3.00 for each additional copy. [ ] paper, july 2000, isbn 1-919770-20-8 price r215.00 (incl. vat) carriage r22.00 for 1st book, r5.00 for each additional copy. [ ] combo: cd-rom + paper, price r277.50 (incl. vat) carriage r25.00 for 1st book & cd-rom, r5.00 for each additional set. orders: south african medical association, private bag x1, pinelands 7430. tel (021) 531-3081, fax: (021) 531-4126 e-mail: jstrydom@samedical.org prepayment by cheque or visa/mastercard required. local stock. 8 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:jstrydom@samedical.org original research article does heart rate adequately reflect exercise intensity during mini-trampoline exercise? adele r w eston (phd) anw ar khan (mmedsc) maurice mars (mb chb) department of physiology, nelson r mandela medical school, university of natal, durban abstract objectives. quantification o f exercise intensity for exer­ cise prescription on the m ini-tram poline is difficult, as the relationship between heart rate (hr) and oxygen con­ sum ption ( v 0 2) during m ini-tram poline exercise is not clear. the aim s o f this study w ere to elucidate the rela­ tionship between hr and v 0 2 during mini-tram poline exercise, and to com pare this with the equivalent rela­ tionship obtained during treadm ill running over a com ­ parable range of hrs. r design. fifteen male subjects aged 1 7 2 4 years jogged on a m ini-tram poline at cadences o f 1 0 0 , 1 2 0 , 160 and 2 0 0 steps/min w ith a 15 cm leg lift, and at a fu r­ th e r w orkload o f 120 steps/m in w ith 90° hip flexion. a fter a 90-m inute rest period, five subm axim a] treadm ill w ork­ loads w ere selected fo r each subject to give a sim ilar range o f hrs to those achieved on the mini-tram poline. following the fifth w orkload on the treadm ill, subjects continued to exhaustion fo r determ ination o f peak v 0 2. main outcom e measures. v 0 2, hr, minute ventilation, tidal volume, and breathing frequency before and during exercise. results. v 0 2 relative to hr w as significantly lower dur­ ing exercise on the m ini-tram poline (p < 0.001). hrs obtained during m ini-tram poline exercise overestim ated v 0 2 by up to 450 ml/min when com pared with treadm ill exercise at the sam e hr. the relationship between v 0 2 (m l/m in) and hr (beats/min) on the treadm ill w as linear: v 0 2 = 19.99 x hr 1 046 (r2 = 0.97), while the relationcorrespon dence: p rofessor m mars d epartm ent o f physiology nelson r m andela medical school u niversity o f natal private bag 7 congella, 4013 kwazulu-natal tel: 031 260 4364 fax: 031 260 4455 e-mail: m ars@ m ed.und.ac.za ship between v 0 2 and hr fo r tram poline exercise . showed a pronounced elevation in hr before any elej , vation in v 0 2. the mean v 0 2 w hile stepping at 120 steps/min with a leg lift o f 90° hip flexion w as signifif cantly higher than w ith a leg lift o f 15 cm (2.10 l/min v. : 1.97 l/min, p < 0.001), ; conclusions. these results suggest that the use o f hr , as a sim ple m onitor o f exercise intensity and the use o f j step frequency as the method o f changing exercise j ! in te n sity durin g m in i-tra m p o lin e jo g g in g should be } , viewed w ith caution'. . introduction running or bouncing pn a m ini-tram poline or ‘rebounder’ has been advocated as a sim ple m eans o f achieving aerobic fit­ ness and w eight lo ss . '2 the m ini-tram poline is relatively inexpensive, small, portable, and offers the benefit o f a low im pact w orkout in a confined space. it is therefore suitable fo r home exercise. despite the m ini-tram poline having been developed in 1938 and patented in 1975, the physiological response to rebounding rem ains unclear and very little has been published to support the claim s o f improved cardiovas­ cular fitness and w eight loss.9 exercise prescription fo r im provem ent o f cardiovascular fitness requires quantification of the intensity o f the exercise performed. exercise energy costs on the m ini-tram poline reported in five studies2'46910 show a variation o f 279% . this indicates that a range o f exercise intensities can be obtained on the m ini-tram poline .9 m ethods o f changing the intensity of m ini-tram poline running or bouncing include changing the fo o t strike frequency ,59 the height o f leg lift12 and the addition o f sim ultaneous ‘pum ping’ o f hand-held w eights. 10 heart rate (hr) has been proposed as a m eans of quantifying exercise intensity on the rebounder, 12 and has been used in training studies .34 target hrs of 70 85% o f age-predicted maximal hr (h r max) are said to be required to achieve aerobic train­ ing using the m ini-tram poline . 12 w hile the oxygen consum ption (v 0 2) to hr relationship (v 0 2/hr) fo r treadm ill running is w ell established, it is not well defined fo r exercise on the mini-tram poline. it is con­ ceivable that exercise involving spring-assisted vertical movem ent may alter venous return and stroke volum e and thereby affect the v 0 2/h r relationship. bhattacharya e t a!.' reported a linear v 0 2/h r relationship w ith tw o-footed bounc­ sports medicine march 2001 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:mars@med.und.ac.za ing on a ‘regular size ’ trampoline at foot-lift heights o f 18 1 0 0 cm, with no difference between tram poline and tread­ m ill-derived v 0 2/h r relationships.1 at any given hr, the average v 0 2 on the tram poline was, however, not signifi­ cantly low er than the treadmill-derived v 0 2. gerberich e f a/ . 5 measured the relationship between v 0 2 and hr during m ini-tram poline and treadm ill jogging in a group of occupationally sedentary women. a 17% increase in hr with a 14% increase in v 0 2 was reported over a range o f stepping frequencies from 105 ste p s/m in to .2 0 5 steps/min on the mini-tram poline. at rebound jogging cadences o f 105 165 steps/min, v 0 2 (ml/min) was unchanged, w hile hr rose from 156 to 170 beats/min. this unusual observation was not elaborated upon. in addition, at any given hr the average v 0 2 obtained on the trampoline w as also low er than that obtained on the treadmill. these findings have not been confirm ed, nor have the ventilatory responses to different stepping frequencies been reported. data on energy expenditure during m ini-tram poline use, w hich would be useful for optimising exercise prescription for w eight loss, are also limited. reported v 0 2 varies from 1 7 4 0 m l/kg/m in .2610 this broad range is probably a reflec­ tion o f the variation in m ini-tram poline technique, particularly with regard to stepping frequency and leg-lift height. a limited num ber o f training studies using rebounding exercise have been completed investigating cardiovascular improvem ents and w eight loss. some report a significant im provem ent in v 0 2max,411-13 while one showed no significant im provem ent.3 d escriptions o f m ini-tram poline protocols used in these studies are scanty and certainly not standard­ ised between studies with regard to step frequency and step height. step frequency has varied considerably and leg-lift h eight is fre q u e n tly unspecified. som e studies have involved ‘rebound aerobics’ rather than jo g g in g .11 the aims of this study w ere to investigate the v 0 2/h r relationship over a sim ilar range of hrs on both the m ini­ tram poline and the treadm ill and to investigate concurrently the effect of step frequency and leg-lift height on hr, v 0 2 and ventilatory param eters while exercising on the m ini­ tram poline. methods subjects eighteen m ale subjects aged 17 24 years w ere recruited for this study. all w ere healthy and active, with a considerable range in the level of daily activity within the group. one sub­ je c t experienced cram p of the hip flexors during the trial and was unable to com plete the testing protocol. hr data were incom plete fo r tw o subjects and their results w ere excluded, leaving 15 subjects for analysis. informed written consent' was obtained from all subjects and the study was conducted with the approval o f the ethics and research com m ittee of the faculty o f medicine, university o f natal. procedures all subjects w ere fam iliarised with both m ini-tram poline and treadm ill jogging before testing. prior to the com m encem ent o f testing, the subjects’ height and w eight w ere measured, and a medical history obtained. a multi-gtage submaximal exercise protocol was then com pleted on the mini-tram po line. this was followed by a m ulti-stage subm axim al exercise protocol on the treadmill, w hich was then extended to elicit a maximal response. it w as not possible to random ise the order o f the two tests as the treadm ill w orkloads for each subject were assigned according to the range o f hrs achieved during the m ini-tram poline protocol and because of the maximal nature of the treadm ill protocol. the subjects performed a five-stage subm axim al protocol on the m ini-tram poline at stepping frequencies from 1 0 0 to 200 steps/m in (table i). the duration o f the first workload was 5 minutes, with subsequent w orkloads lasting 3 min­ utes. there was a 1-minute rest interval between each o f the first four w orkloads and a 5-m inute rest interval before the final workload. step frequency was tim ed to a metronome. a step height o f 15 cm w as used for the first four stages and w as closely monitored by a designated observer using mea­ sured vertical markers. leg lift fo r the fifth stage required subjects to flex their hips to 90° during each stride. the step frequency o f 1 2 0 steps/min chosen fo r com parison o f leg-lift heights w as based on katch e f a/.’s6 observation that a step frequency o f approxim ately 1 2 0 steps/m in w as the most com m on naturally selected frequency when m ini-tram poline jogging. tab le i. five stage m ini-tram poline protocol s tep pin g freq uen cy (step s/m in)* s tep h e igh t (cm ) duration (m in) 100 15 5 120 15 3 160 15 3 200 15 3 120 90° to vertical 3 * e ac h foot strike equals one step, t t h e subject's hip is flexed to 90°. subjects then rested fo r 90 minutes before undertaking the treadm ill protocol (pow erjog eg10). during this tim e sub­ je cts were allowed to drink water. mean resting hr after 90 minutes o f rest w as no different to that before the m ini-tram poline protocol. w orkloads w ere of the same duration and w ith the sam e rest intervals as during the m ini-tram poline exercise. w orkloads w ere individually assigned according to the range of hrs achieved by each subject during the m ini­ tram poline exercise protocol, with knowledge o f their tread­ mill hr response from the fam iliarisation session. the first tw o w orkloads w ere at w alking speeds, with the remaining three at running pace with increases in speed and slope between w orkloads. a fter the fifth workload, slope and speed were increased every minute until the subject could no longer continue. in all instances, the hr at the point of exhaustion was more than 90% o f the predicted hrmax for age and in all but two cases, the respiratory exchange ratio (rer) was greater than 1.05. the gas exchange analysis was performed using open circuit spirom etry (oxycon gamma, m ijnardt) calibrated for gas concentrations and volum e before every testing session. 10 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) throughout both mini-tram poline and treadmill exercise, m inute ventilation (ve), v 0 2 and rer w ere measured con­ tinuously. hr w as measured every 5 seconds throughout exercise using telem etry (polar sport tester hr monitor). all values reported are those averaged over the last 30 seconds o f the workload. energy expenditure, based on the thermal equivalent o f oxygen adjusted for the rer, was calculated at each w o rklo a d .7 a dditional investigations in five subjects confirmed that subm axim al m ini-tram poline exercise followed by 90 minutes o f rest did not influence v 0 2 or hr response during the treadm ill protocol. statistical analysis data are presented as mean and one standard deviation (sd). the effect of w orkload and mode o f exercise (mini­ tram poline v. treadm ill) on v 0 2 with regard to hr was deter­ mined by tw o-w ay analysis o f variance with repeated m easures. the effect o f m ini-tram poline stepping cadence on respiratory responses was determ ined using a one-way analysis o f variance (anova). comparison o f leg-lift height w as carried out using the s tu d e n t's paired f-test. correlations between variables utilised pearson’s correlation coefficient. significance was set at p < 0.05. results the subjects’ age, mass, height and v 0 2max are shown in table ii. m ean hr and v 0 2 for each subm axim al workload during m ini-tram poline and treadm ill exercise and the maximal data from the treadm ill exercise test to exhaustion are presented in table iii. there w as an increase in both v 0 2 and hr with increased stepping frequency ( 1 0 0 2 0 0 steps/min) on the mini-trampoline and with increased workload on the treadmill. table ii. subjects’ characteristics ( n = 15) c h a rac teristic . m ean range age (yrs) 20.9 (1.8) 1 7 2 4 mass (kg) 63.6 (4.7) 58.2 73.8 height (cm) 170.9 (3.7) 1 6 2 .5 176.7 v 0 2ma, (ml/kg/min) 52.3 (5.9) 40.9 59.6 v 0 2ma, (l/min) 3.32 (0.42) 2.55 3.83 in order to compare v 0 2 relative to hr during the two modes o f exercise, the oxygen pulse (v 0 2 per heart beat) was examined. for ease of comparison, treadm ill v 0 2 values were modelled for the exact hrs obtained during mini-tram poline exercise, using the treadmill v 0 2/h r relationship derived from the treadmill linear regression equation in fig. 1 . the differences in voa and oxygen pulse between trampoline and treadmill exercise at any given hr are shown in table iv. h r (b e a t s / m in ) fig. 1. relationship between hr and oxygen consumption on treadmill and on the mini-trampoline at stepping frequencies o f 100, 120, 160 and 200 steps/min and 200 steps/min with 90° hip flexion. the regression equation for treadmill data is v 0 2 (ml/min) = 19.99 x h r 1 046. two-way anova indicated a significant effect of mode of exercise on the oxygen pulse, with a low er result during trampoline exercise (p < 0.001). thus at any given hr, v 0 2 was higher on the treadmill than on the mini-trampoline. the magnitude of the difference is shown in table iv. although there was no significant interaction effect of mode o f exercise and increasing exercise workload on oxygen pulse (p = 0.08), the data displayed in fig. 1 reflect the trend toward a different slope of the v q 2 v. hr relation­ ship. during treadm ill exercise, hr and v 0 2 both increased from workload 1 through to m aximum workload, resulting in a linear relationship (v 0 2 (ml/min) = 19.99 x hr (beats/min) 1 046, r2 = 0.97). during m ini-tram poline exercise, hr was increased with each increase in stepping frequency, while v 0 2 only increased significantly when the step frequency was raised to 200 steps/min (p < 0.01). this was an unex­ table iii. heart rate and oxygen consumption during mini-trampoline and treadmill exercise, expressed as mean and 1 sd m in i-tram po line treadm ill heart rate < o heart rate < o steps/min . ( beats/minutes) (l/min) stage (beats/min) (l/min) 100 134 (19), 1 .5 7 (0 .3 6 ) 1 143 (14) 1.81 (0.16) 120 147 (17) 1.53 (0.32) 2 153 (16) 1.9 7 (0 .1 8 ) 160 153(19) 1.56 (0.25) 3 160 (17) 2.17 (0.23) 200 166 (-19) 2.00 (0.29) 4 169(17) 2.41 (0.19) 120/90° 1 7 3 (1 5 ) ' 2.14 (0.27) 5 180 (15) 2.50 (0.18) max 201 (6) 3.32 (0.42) sports medicine march 2001 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ta b le iv. com parison o f mean oxygen consum ption and oxygen pulse at hrs obtained during tram poline exercise. the m ean treadm ill oxygen consum ption is calculated from the regression equation derived in fig. 1 , and th e mean treadm ill oxygen pulse is calculated from the m odelled treadm ill oxygen consum ption hr tram p o lin e (b eats/m in) v o z tram p o lin e (ml/m in) v o 2 tread m ill (m l/m in) d ifference (m l/m in) . 0 2 pulse tram po line (m l/b eat) 0 2 pulse tread m il (m l/b eat) d ifference (m l/b eat) 134 1 5 7 0 1 6 3 4 64 11.72 1 2 .1 9 • 0 .4 8 1 4 7 1 5 3 0 1 8 9 4 3 6 4 10.41 1 2 .8 8 2 .4 7 1 5 3 1 5 6 0 2 0 1 4 4 5 4 1 0 .2 0 1 3 .1 6 2 .9 7 1 66 2 0 00 2 2 7 4 2 7 4 1 2 .0 5 1 3 .7 0 1 .6 5 1 7 3 2 140 2 4 1 4 2 7 4 1 2 .3 7 1 3 :9 5 1 ,5 8 pected finding and more interm ediate stepping frequencies are required in order to describe the curve with precision. the mean hr and v 0 2 obtained at a step frequency of 120 steps/min with the hips flexed to 90° on the m ini-tram poline was significantly greater than with a fo o t lift of 15 cm (p < 0.001) (table iii). the mean energy expenditures a t the different step frequencies are shown in fig. 2. .? 12 1 ik 120 140 160 200 120/90 s teps/m in fig. 2. energy expenditure a t the different stepping frequencies expressed as mean and one standard deviation. the ventilatory changes during m ini-tram poline jogging are shown in table v. w ith increasing step frequency on the m ini-tram poline, v e and respiratory rate increased signifi­ cantly (p < 0.001), in a fashion best described by a third order polynom ial, although m ore points are required to describe this relationship with precision. in contrast, tidal volum e w as not significantly increased over the range of step frequencies used in this study despite the increase in v e, w hich m ust therefore be accounted fo r primarily by the increases in breathing frequency (p < 0.001). a t 120 steps/m in with higher leg lift, the respiratory rate w as less than at 200 steps/min, despite the 120 steps/min with 90° hip flexion workload provoking a higher v e and v 0 2. the relationship between % h r max and % v 0 2max differs between the tw o exercise m odalities. w hen exercising on the tram poline, a higher percentage o f h r ^ i s required to achieve a % v 0 2max com parable with that achieved on the treadm ill. for example, 75% h r max represents 60% v 0 2max during treadm ill exercise, w hile during m ini-tram poline exer­ cise, 75% h r max equates to only 47% v 0 2max(fig. 3). the percentage of hrmax utilised by individuals when exercising on the m ini-tram poline at step frequencies of 1 2 0 steps/min and 160 steps/min show s a w eak relationship with individu­ a ls ’ v o 2m0x (table vi). % hrmax fig. 3. the relationship between %hrmax and % v 0 2m3x on tread­ mill and on the mini-trampoline. table v. ventilatory results during m ini-tram poline exercise expressed as m ean and 1 so s tep s/m in v e (l/m in) vt(i) f (b reath s/m in) s tep s/b reath v6/v02 1 00 3 2 .6 (9 .3 ) 0 .9 7 (0 .3 0 ) ' 33.1 (1 0 .4 ) 3 .0 2 0 .8 1 20 3 8 .4 (1 1 .1 ) 0 .9 9 (0 .2 7 ) 3 8 .0 (1 2 .7 ) 3 .2 25.1 160 4 0 .0 (8 .6 ) 1 .0 0 (0 .2 7 ) 4 0 .0 (1 2 .4 ) 4 .0 2 5 .6 2 0 0 5 2 .7 (1 2 .7 ) 1 .1 7 ( 0 . 3 3 ) 4 5 .6 (1 6 .8 ) 4 ,4 2 6 .4 1 2 0 /9 0 ° 5 4 .4 (9 .4 ) 1 .3 2 ( 0 . 3 0 ) 4 2 .1 (1 3 .2 ) 2 .9 2 5 .2 v6 = minute ventilatory volume; vt = tidsi volume; f = respiratory rate; ve/v 0 2 = oxygen equiavalent. 12 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table vi. correlation o f the percentage o f hrmax with the perecntage v 0 2max achieved on the mini-trampoline %hrmax at 100 steps/min r = 0.42, ns %hrmax at 120 steps/min r = 0.58, p < 0.05 %hrmax at 160 steps/min r = 0.55, p < 0.05 %hrmax at 200 steps/min r = 0.31, ns %hrmax at 120/90° steps/min r = 0.10, ns n s = not significant. discussion in a review o f rebounding exercise and cardiorespiratory fit­ ness, sm ith and bishop m ade the following assertion, ‘o bviously the rate at w hich a subject jogs on a rebounder will influence the energy cost’ .9 in the present study, at a foot lift o f 15 cm, an increase in the jogging rate did not, however, provoke an increase in v 0 2 or energy expenditure except at the highest step frequency o f 2 0 0 steps/min. as the m ini-tram poline is a popular exercise m odality in the home, w here the sim plest objective m easure o f exercise intensity is hr, a knowledge o f the v 0 2/h r relationship is important. v 0 2 w as consistently low er during exercise on the m ini-tram poline when com pared with treadm ill exercise at a com parable hr. in addition, the v 0 2/h r relationship observed while jogging on the m ini-tram poline w as non­ linear, w ith the hr relative to the m easured v 0 2 being dis­ proportionately high at stepping frequencies of 1 0 0 , 1 2 0 and 160 steps/m in. as no m easurem ents w ere taken between 160 and 2 0 0 steps/min, it is not possible to clarify the point or nature of the inflection in the v 0 2/h r curve. this finding partially supports the findings o f g erberich et al.’s study5 o f untrained w om en, w hich did not illustrate a significant increase in v 0 2 even at the higher workloads. the cause o f the increasing hr w ith an unchanging v 0 2 is unclear. if the constant v 0 2 reflects a constant cardiac out­ put, then the increase in hr may be explained by a reduc­ tion in stroke volume secondary to possible changes in venous return. venous return may be altered by vertical m ovem ent and reduced calf muscle pump activity or breath­ ing pattern relative to vertical m ovem ent. this response requires further investigation. the v 0 2 and associated energy expenditure observed in the current study fell within the range o f values reported in previous studies .610 a t the low er three stepping frequencies, v 0 2 w as below that recom m ended fo r im provem ent in car­ diovascular fitness .8 even at a stepping frequency as high as 160 steps/m in, the mean v 0 2 o f 1.56 l/min (24.5 m l/kg/min), represented 47% of v 0 2max with a range o f 27% v 0 2max 6 8 % v 0 2max. this exercise intensity is unlikely to result in signifi­ cant im provem ents in cardiovascular fitness, nor is it likely to be associated with substantial w eight loss. use o f hr target zones fo r training has become popular, and 70% hrmax is often quoted as the threshold level above w hich aerobic training effects will occur. extrapolation o f data from the m ini-tram poline and treadm ill % hrmax/% v 0 2max curves indicate that a level o f v 0 2 com parable with that achieved at 70% hrmax on the treadm ill is achieved at approxim ately 80% hrmax on the mini-tram poline. hrs in excess o f 80% hrmax w ere only achieved at a step frequen­ cy of 200 steps/min with a 15 cm lift, and at 120 steps/min with 90° hip flexion. the height o f leg lift significantly affects v 0 2, and at 120 steps/min an increase in the leg lift from 15 cm fo o t lift to 90° o f hip flexion resulted in an increase in the v 0 2 o f 41 % (p < 0.001). this is in contrast to an increase in v 0 2 o f only 3% when stepping frequency w as increased from 120 to 160 steps/min. a significant 31% increase in v 0 2 was obtained when stepping frequency was increased to 200 steps/min (p < 0.001), but this stepping frequency requires consider­ able co-ordination and motivation from the subjects. studies investigating the use o f hand-held w eights while mini-tram polining have reported an increase in energy expenditure of a sim ilar degree, dependent upon the w eight and the ‘pump­ ing’ height. increasing the height of leg lift m ay be a suitable and sim pler alternative to the addition o f hand-held w eights.'0 energy utilisation at hr zones com m only associated with training and aerobic weight reduction programmes is low er in tram poline jogging than in treadm ill running and may be insufficient to achieve the desired effect. the use o f hr as a sim ple m onitor of exercise intensity and the use of step frequency as the method o f changing exercise intensity during m in i-tram poline jo g g in g should be view ed with caution. further studies o f w ays to increase exercise intensity and v 0 2 using the m ini-tram poline are required, and the cause o f the reduction in v 0 2 relative to hr in tram poline jogging w arrants further investigation. traditional target hr zones need to be reassessed fo r use with m ini-tram poline jogging. r e f e r e n c e s 1. bhattacharya a, shvartz e, mccuthcheon ep, greenleaf je. body accel­ eration distribution and 0 2 uptake in humans during running and jumping. j appi physiol 1980; 49: 881-7. 2. cooter gr, tinklepaugh p. physiological response to exercise on a ‘rebounder’. southern c hapter o f the american college o f sports medicine selected research abstracts 1983: 38. 3. evans bw, clairborne jm, thomas s. changes in aerobic capacity and body composition subsequent to an eight week rebounding running pro­ gram. med sci sports exerc 1984; 16: 104. 4. gerberich sg, bishop pa, leon as. the effects of rebound exercise upon physical fitness, body composition, and blood lipids. med sci sports exerc 1983; 15: 90. 5. gerberich sg, leon as, mcnally c, serfas r, edin j. analysis of the acute physiologic effects of minitrampoline rebounding exercise. journal o f cardiovascular rehabilitation 1990; 10: 395-400. 6. katch vl, villanacci jf, sady sp. energy cost of rebound running. res q exerc sport 1981; 52: 269-72. 7. mcardle wd, katch fi, katch vl. measurement of human energy expen­ diture. in: exercise physiology. 3rd ed. philadelphia: lea and febiger, 1991: 145-57. 8. shephard rj. aerobic fitness and health. champaign: human kinetics, champaine 1994; 208. 9. smith jf, bishop pa. rebounding exercise. are the training effects suffi­ cient for cardiorespiratory fitness. sports med 1988; 5: 6-10. 10. smith jf, bishop pa, ellis l, conerly md, mansfield er. exercise intensi­ ty increased by addition of handheld weights to rebounding exercise. j cardiopulm rehabii 1995; 15: 34-8. 11. tomassoni tl, blanchard ma, goldfarb ah. effects of rebound exercise training program on aerobic capacity and body composition. the physician in sportsmedicine 1985; 11: 111-15. 12. walker m. jumping fo r health: a guide to rebounding aerobics. new york: avery publication group, 1989: 10-28. 13. w hite jr. changes following ten weeks of exercise using a minitrampo­ line in overweight women. med sci sports exerc 1980; 2: 103. sports medicine march 2001 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research article clustering of athletic ability in male kalenjin scholars m nurok (mb chb) a g morris2 (phd) c o ’connell3 (ba) t d noakes1 (mb chb, md, facsm) . 'mrc/uct research unit for exercise science and sports medicine, university of cape town and sports science institute of south africa, newlands, cape town de p a rtm e n t of anatomy and cell biology, university of cape town 3former headmaster, st patrick’s school,. iten, kenya i abstract ! aim . the present study aim ed to establish any biologi ( cal or socio-cultural differences between a group o f run j ners and non-runners attending high school in the heart j o f kenya’s kalenjin-speaking region, f m ethods. a case-controlled dem ographic and anthropo j m etric study w as perform ed on schoolchildren at st i patricks school, kenya. two sam ple groups w ere used. ! the first group consisted o f pupils w ho participated in athletics, and the second group consisted o f pupils who did not. results. eighteen o f the runners had a t least one first j degree relative involved in com petitive running, while of | the non-runners, tw o had a first-degree relative running competitively. runners tended to be heavier and taller i than non-runners and jum ped significantly further in the ! standing long jum p test. i conclusions. these data could support the hypothesis ; that among the kalenjin kenyan tribe, there exists on a , hereditary basis specific lineages with superior running { ability. alternatively, the social-cultural hypothesis that a j proven fam ily history of running ability encourages | potential adolescent runners to follow the fam ilial exam ; pie may also be supported by these findings. introduction there is substantial speculation th a t specific biologically defined populations have genotypes th a t enable them to succeed in given athletic events at a rate disproportional to those w ithout the speculated genotype .4 areas o f focus correspondence: t d noakes sports science institute o f south africa po box 115, newlands, 7725 tel: 021 650 4557 fax: 021 6 8 6 7530 e-mail: td n o akes@ spo r ts.uc t.ac.za include the com petitive successes o f w est african sprinters and east african long distance runners,2,811 and elite black male south african long distance runners .313-14 a previous study3 showed that elite black male south african long dis­ tance runners dem onstrated ‘superior fatigue resistance' to their non-black counterparts. this finding could explain why 90% o f the top positions in south african road races from 5 to 56 km are filled by black athletes,3 w ho com prom ise less than 20% o f the south african running population. as early as 1944, the south african scientist ernst jokl5 speculated that: ‘serious consideration should be given to the hypothe­ sis that the negro muscle — in contrast to the muscles o f whites — is a superior m achine, producing from a given am ount of fuel more energy and less heat'. in recent years kenyan runners have dom inated long and middle distance running events .6912 kenya’s more than 40 indigenous languages, which correspond closely with ethnic groups or tribes, are commonly classified as bantu, nilotic or cushitic. approximately three-quarters of kenya’s international runners come from a nilotic group known as the kalenjin, who comprise about 11% o f the kenyan population.715 manners6 has suggested th a t the conventional explana­ tions for the extraordinary com petitive success o f kenyan runners — living at 2 0 0 0 m altitudes, enjoying the ideal cli­ mate o f the kenyan highlands, subsisting on a high carbo­ hydrate diet, using walking o r running as a principal mode o f tra n sp o rta tio n and stro n g ly m otivated by the m aterial rew ards available to successful runners — do not adequate­ ly explain the concentration of running success am ong the kalenjin. he invokes the possibility of genetic predisposition to running ability based on a collection o f case studies and the hypothesis that custom s peculiar to the kalenjin people may have acted as selective pressures tow ards such genet­ ic ability. these include cattle raiding, w hich called fo r long treks w here speed and endurance w ere essential, and which was rewarded by increased ability to pay fo r brides. if this hypothesis is correct and the relevant custom s have been practised fo r m any centuries, one w ould expect running abil­ ity to be distributed throughout the kalenjin population, as indeed m anners6 and his inform ants believe. however, based on the high degree o f biological relations among inter­ nationally successful kalenjin runners, there is also the sug­ gestion that even within the kalenjin and perhaps other kenyan populations, specific lineages with superior running ability may exist. 14 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:tdnoakes@sports.uct.ac.za eldoret is the second largest town in the rift valley province. n ear eldoret lies iten, hom e o f st p atrick’s school, w hich has, over the years, produced a disproportionate num­ ber o f elite kenyan runners.12 st p atrick’s has developed a lim ited policy o f preferentially adm itting athletically talented pupils w hose academ ic standard may otherwise have pre­ cluded their entrance into the school. the present study aimed to establish w hether there w ere any biological or socio-cultural differences between a group o f runners and non-runners, all o f w hom attend st patrick's school in the heart o f kenya’s r ift valley province. material and methods the case-control study w as conducted at st p atrick’s school, iten, kenya. the form er headm aster and running coach at the school and coach to a num ber o f other elite kenyan athletes (c o ’c), adm inistered a standard question­ naire to 50 male students at the school between the ages o f 15 and 21 years. two sample groups w ere used. the first (n = 25) w as com posed o f pupils w ho participated voluntar­ ily in athletics as an extra-curricular activity. the second sam ple (n = 25) consisted o f pupils w ho did not participate in athletics. all these boys w ere born and grew up in kenya's rift valley. the questionnaire detailed: (/) dem o­ graphy, including questions regarding parents’ highest level o f education; (ii) w hether there w ere any first-degree rela­ tives who participated in com petitive running and at w hat level; (iii) tribal background dating back to m aternal and paternal grandparents; and (iv) w hat students planned to do after leaving school. a standing long jum p test was also adm inistered to all participants. the test required both feet to be flat on the ground, shoulder width apart, toes ju st behind the line, knees at 120°, and arms to the sides. a counter m ovem ent o f the arm s was allow ed im m ediately before the jum p. the jum p was measured to w here the heels landed. three opportunities were given, and the best result was recorded. additionally, pupils w ere weighed to the nearest kilogram , and height was m easured to the nearest centim etre. this inform ation was used to calculate the body mass index (bmi) (kg/m 2). a standard chi-square analysis w as perform ed to assess the significance o f differences betw een variables in the two groups for each o f the following: related running relatives, tribal background, level o f parental education, and intention to pursue fu rth e r'e d u ca tio n . a student’s (-test w as per­ form ed to assess the significance o f differences between bmis of runners and non-runners, long jum p differences, height and w eight differences, age differences, and differ­ ences between centim etres jum ped per kilogram o f body weight. results o f the 25 runners, 23 could confidently trace their origins to kalenjin o r one o f the kalenjin sub-tribes, bilaterally for two generations. twenty-one o f the non-runners could do like­ wise. there was no significant difference between the tribal background o f runners and non-runners. o f the runners, 16 had at least one parent with post-prim ary school education, w hile 19 o f the non-runners had a t least one parent with post-prim ary school education. this difference w as not significant (table i). eighteen o f the runners had a t least one first-degree relative involved in com petitive running. these 18 included 4 international, 4 national, 2 provincial, 5 district and 1 zonal runner(s). o f the non-runners, 2 had at least one first degree relative running competitively, 1 at provincial level and 1 at district level. this difference w as significant (p < 0.001, table i). ten runners intended to seek post-secondary school edu­ cation, while 24 non-runners had a sim ilar intention. this dif­ ference w as significant (p < 0.001, table i). o f the 15 runners who did not intend to seek such education, 6 hoped to become professional athletes, and 9 hoped to seek em ploym ent. w hen the 6 intending to becom e professional athletes w ere rem oved from the group, leaving 10 o f 19 run­ ners intending to pursue post-secondary education, the num ber w as still significantly (p < 0.001, table i) less than the 24 of 25 non-runners intending to pursue such education. w hen the runner sam ple w as broken down into runners com peting at provincial level and above and those com pet­ ing below this level, 4 o f the 11 runners com peting at the higher level intended to pursue a career in athletics com ­ pared with 2 o f the 1 2 runners competing at the lower level. this difference was not significant. table i. socio-cultural com parison between runners and non-runners attending st patrick’s school, iten, kenya c ate g o ry value) r un ners (n) n on -runn ers (n) s ig n ifica n ce (pexclusively kalenjin background over 23125 21/25 ns two generations one or more first-degree relatives 18/25 2/25 < 0.001 running competitively one or more parents with post-primary 16/25 19/25 ns school education intention to seek post-secondary education 10/25 24/25 < 0.001 intention to seek post-secondary 10/19 24/25 < 0.001 education, excluding subjects intending to become professional athletes sports medicine march 2001 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table ii. anthropometrical data (mean (sd)) for runners and non-runners m easu rem en t r unners n on -runn ers s ig n ificance (p-value) age (years) 17.6 (1.114) 16.8(1.218) < 0.05 height (m) 1.74 (0.06) 1.65 (0.08) < 0.001 weight (kg) 57.9 (5.29) 52.5 (8.27) < 0.05 body mass index (kg/m2) 19.06 (1.28) 19.09 (2.21) ns best standing long jump (m) 2.29 (0.21) 1.90 (0.21) < 0.001 long jump/weight (cm/kg) 3.97 (0.39) 3.71 (0.78) ns table ii lists the anthropom etrical data of runners and non-runners and their standing long jum p perform ance. the tw o groups w ere not ideally m atched as runners w ere signif­ icantly older, heavier and taller, but bmis w ere not different between the tw o groups. runners also dem onstrated less variation in body mass than the non-runners. runners jum ped significantly further in the standing long jum p, but this difference disappeared when results w ere corrected for differences in body mass. discussion the finding that the tribal backgrounds of runners and non­ runners w ere not significantly different suggests that both sam ples w ere indeed from one population. accordingly, the most notable finding of this study was that the schoolboy run­ ners had an overw helm ing preponderance of first-degree rel­ atives also involved in com petitive running. in contrast, only 2 (8 %) o f the schoolboy non-runners had a close relative participating in com petitive running. st p atrick’s longstanding reputation for producing out­ standing runners, m any o f whom have achieved internation­ al success, has made it the institution of choice in the rift valley province for boys who have serious running am bi­ tions. in view of this, the marked difference in the figures for relatives involved in com petitive running suggests one o f two possible interpretations. it can be argued6 that the difference results from fam ily differences in role m odels and encour­ agem ent — boys encouraged to run by other runners in the im m ediate fam ily are more likely to seek education at st p atrick’s and to participate in athletics after joining the school. or, alternatively, perhaps instead of or in addition to these social effects, the data offer strong support fo r the initial hypothesis that among the kalenjin there exists on an hereditary basis specific lineages with superior running abil­ ity. it should be noted that athletics at st p atrick’s is open to all scholars, and the rewards earned by successful runners, nam ely opportunities to travel and possible scholarships to am erican colleges or professional running careers, are fam iliar to every boy in the school. yet the school’s runners com e predom inantly from fam ilies whose mem bers include other com petitive athletes. however, there are important lim itations to this study that need to be recognised. first, neither of the tw o sam ple populations w as ran­ dom ised, nor w ere the tw o sam ples well m atched for age. second, the reliability of the measuring instrum ents is not known. finally, we failed to establish w hat percentage o f the runner sam ple w as attending the school as a result of st patrick’s preferential adm issions policy. in view of these considerations, these results should be considered provisional pending a sim ilar study conducted by researchers using larger random ised age-m atched samples and certified measuring equipm ent, taking into account the num ber o f preferentially adm itted athletes. if the present results are confirm ed, a further study would be needed to test the hypothesis that lineages with superior running abili­ ty exist on a biological basis. this study would need to per­ form physiological tests on the younger siblings of fam ilies with and w ithout histories o f athletic excellence before the siblings had started running, and therefore before they had experienced a training effect. surprisingly, the bmis o f the tw o groups w ere essentially identical. as the teenage years are the m ost m etabolically expensive of an individual's life, and as running would add a further m etabolic stress, one w ould expect the runners to have lower bmis. this is especially true for kenyans in iten who m ust subsist, for econom ic reasons, on a high-bulk, low caloric rural d ie t.12 it may be that the runners sim ply ate more than the non-runners, as food at st p atrick’s is not strictly rationed and the kilojoule intake of the populations was not m onitored. alternatively, the runners’ m etabolic rates may have adapted to higher energy dem ands and a relative caloric deficiency. r unners w ere taller and heavier than non-runners. this could be because runners w ere older, although growth velocity generally declines in the late te e n s .10 alternatively, runners m ight com prise a separate population within the kalenjin-speaking people or they may indeed have enjoyed better than average nutritional circum stances. the significantly better perform ance of the runners in the long jum p may be explained by their greater height and pre­ sumed greater stride length. an alternate explanation would be th a t the runners w ere more powerful, again either on a genetic basis or as a result of their training. the finding that a disproportionate num ber of athletes com peting at provincial level and above intended to pursue a career in athletics suggests that running perform ance may influence career choice. the know ledge that close relatives pursued a running career w ould probably act as the spur to start running. however, new runners must also be aware of the large num ber o f kalenjin runners w ho do not achieve international success or for whom international success does not guarantee long-term financial security.1612 this explanation, however, does not tell us w hy runners not planning to pursue a career in athletics do not intend to pursue post-secondary school education. this is especially surprising since the educational levels of the parents of the runners and non-runners w ere similar, and the non-runners 1 6 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) overw helm ingly intended to pursue such education. this finding m ay be an artefact o f st patrick’s preferential adm is­ sions policy, in that a disproportionate num ber o f the running subjects m ay have demonstrated low er academ ic capacity from the start. alternatively, running perform ance could be a better predictor o f career choice in iten than the level o f parental education. in summary, if the localisation o f athletic talent in circum ­ scribed areas o f the rift valley o f kenya1 is due to the bio­ logical pressure o f a high altitude rural lifestyle, then one w ould expect running ability to be distributed throughout the population resident in that area. but this study seems to identify a group o f runners from the sam e population as their non-running counterparts with sim ilar opportunity to partici­ pate in running at school, but with a marked difference in the num ber o f biological first-degree relatives who are com peti­ tive athletes, with sim ilar bmis despite presum ed increased energy expenditure from participating in running, and with sim ilar role m odels in term s o f level o f parental education, yet dissim ilar goals in term s o f education. the argum ent for a biological basis for this finding is sug­ gested by the strong fam ilial links, presum ed more efficient m etabolism , superior relative absolute long jum p ability, and sim ilar parental role models in a population that is otherwise identical. alternatively, an equally convincing socio-cultural expla­ nation can be made by arguing that a proven fam ily history o f running ability encourages potential adolescent runners to follow the fam ilial example, especially as the prospect o f financial success for children born in a poor rural com m unity will be a profound motivator. further, it is possible that lin­ eages w ith superior running ability, if they do indeed exist, may have been formed through a culture o f running. until very recently, social pressures governing mate selection cannot have related directly to com petitive running which has assum ed social significance in kenya in the last 50 years. but success in the possibly related enterprise o f cattle raiding has long been a significant factor in mate selection6 and could have resulted in the observed concen­ trations o f ability. this study was funded by the medical research council and the harry crossley staff research fund of the university of cape town. the authors thank the participants and members of staff at st patrick’s school in iten who made this study possible. informed interpretation of the findings would not have been pos­ sible without liberal access to mr john manners’s encyclopaedic knowledge and intimate understanding of kenya, her people and her runners. his gracious assistance with the preparation and refinement o f the final manuscript is gratefully acknowl­ edged. r e f e r e n c e s 1. bale j, sang j. kenyan running. london: frank cass, 1996. 2. burfoota . white men can’t run. runners world 1992, aug: 89-97. 3. coetzer p, noakes td, sanders b, et al. superior fatigue resistance of elite black south african distance runners. j appl physiol 1993; 75: 1822-7. 4. himes jh. racial variation in physique and body composition. canadian journal o f sports science 1988; 13: 117-26. 5. jokl e. physiological data showing that standards of physical efficiency and of heat resistance of african natives are high. clinical proceedings 1944; 4 : 355-76. 6. manners j. kenya’s running tribe. the sports historian 1997; 19(2): 14 27. also available at htto://www.umist.ac.uk/umist sport/2 art2/htm, 1997. 7. national census data. daily nation (nairobi). 12 march 1994: 3. 8. noakes td. why do africans run so swiftly? a research challenge for african scientists. south african journal o f science 1998; 9 4 : 531-5 9. noakes td. lore o f running. 3rd ed. cape town: oxford university, press, 1992. 10. rudolph mr. rudolph's pediatrics. 20th ed. engelwood cliffs, calif.: prentice hall international, 1996. 11. saltin b, kim ck, terrados n, larsen h, svedenhag j, rolf cj. morphology, enzyme activities and buffer capacity in leg muscles of kenyan and scandinavian runners. scand j med sci sports 1995; 5: 222 30 12. tanser t. train hard, win easy. the kenyan way. mountain view, california: tafnews press, 1997. 13. weston ar, karamizrak o, smith a, noakes td, myburgh kh. african runners exhibit a greater fatigue resistance, lower lactate accumulation, and higher oxidative enzyme activity. j appl physiol 1999; 86: 915-23 14. weston ar, mbambo z, myburgh kh. running economy of african and caucasian distance runners. med sci sports exerc 2000; 32: 1130-4 15. winkler em, sokal rr. a phenetic classification of kenyan tribes and subtribes. hum biol 1987; 59(1): 121;45. sports medicine march 2001 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) http://www.umist.ac.uk/umist original research article popliteal vascular entrapment syndrome — a cause of leg pain to be considered in young athletes lewis j levien (mb bch, fcs(sa), phd, facs) milpark hospital, parktown, johannesburg abstract objective. to provide an explanation for the sym ptom s e xp erienced by, and clinical approach to patients presenting with fo o t and calf pain or paraesthesiae brought on by exercise when such sym ptom s are due to popliteal vascular entrapm ent. design. in this study the clinical features of 93 instances o f popliteal vascular entrapm ent occurring in 51 patients over an 11-year period are presented. in addition, the em bryology of the popliteal artery is reviewed and its rel­ evance to the developm ent o f popliteal entrapm ent explained. setting. the study w as conducted in a single m ajor vascular surgical centre in the johannesburg area, and the cases w ere drawn from all the vascular surgeons practising at that centre. interventions. in patients suspected o f suffering from popliteal vascular entrapm ent, the diagnosis w as confirmed angiographically. patients were subjected to release of the entrapment mechanism if the underlying artery had not yet undergone occlusion, or to replacement o f the popliteal artery if the artery w as occluded. m ain outcom e m easu res. the d ia g no sis was confirm ed by the operative findings, and the adequacy o f treatm ent w as determ ined by the e xtent of relief of sym ptom s and return to sporting activities postopera tively. results. bilateral popliteal entrapm ent w as found in 42 o f 51 patients. the m ean age at the time o f presentation w as 34.9 years (sd 11.6 years). c laudication was the m ost frequent presenting sym ptom (75 of 8 8 limbs). types i, ii, iii and iv popliteal entrapm ent w ere found in 61 limbs (15 arteries occluded), w hile 32 limbs (3 occlu­ sions) presented w ith a ‘functional' popliteal artery entrapm ent (apparent absence o f a developm ental anatom ical abnorm ality). o f 18 lim bs w ith severe ischaem ia and associated occlusion of the popliteal artery, 15 underwent, bypass grafting with reversed saphenous vein grafts. all replacem ent vein grafts rem ained patent during follow-up (m edian 4.2 years, range 1 1 1 years). one patient was treated with vein patch angioplasty w hich re-occluded w ithin 6 months and required vein graft replacement. c onclusions. the popliteal entrapm ent syndrom e is much more prevalent than has form erly been appreciat­ ed. failure to appreciate the diagnosis w hen the patient presents with early sym ptom s usually results in progres­ sion o f the pathology o f the entrapm ent to the point w here degenerative changes in the entrapped vessel culm inate in occlusion and throm bosis. correct diag­ nosis and surgical intervention before the developm ent o f throm bosis at the site o f the entrapm ent results in prom pt and lasting relief o f sym ptom s, and has the additional m ajor benefit o f preventing further degenera­ tion of the involved artery. on the basis o f observations made in this series and in the surgical literature, surgical correction is advised in all cases of types i, ii, iii, and iv entrapm ent at time o f diagnosis to avoid occlusion as a result o f continued arterial w all degeneration. on the other hand, in those patients presenting with sym ptom atic ‘functional’ entrap­ ment, surgery is only advised if the sym ptom s are typi­ cal and severe, since up to 50% o f the normal population dem onstrate transient popliteal artery compression with extrem es o f plantaror dorsiflexion. . on the basis o f the severe histological changes found in those popliteal arteries th a t have undergone occlusion at the tim e o f presentation, it is advised that the popliteal artery should be com pletely replaced, ideally by a vein graft, w hen significant degeneration or occlusion of the popliteal artery is noted at the tim e o f operation. correspondence: d r lewis j levien po box 2738 houghton 2041 tel: 011-726 6789 fax: 011-726 7775 e-mail: ljlevien@ iafrica.com introduction the young athletic individual who presents with sym ptom s of leg and foot pain on exercise presents a problem in diag­ nosis and m anagem ent for the clinician. full and correct evaluation and investigation o f these patients usually per­ mits an accurate diagnosis to be m ade, ' 5 resulting in correct m anagem ent and consequent alleviation o f symptoms. in the young athlete presenting with typical claudication-like sym ptom s o f the calf and foot, popliteal vascular entrapm ent 18 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:ljlevien@iafrica.com is an im portant and reversible cause o f leg pain and paraes thesiae, and m ay be the u n d e rlyin g cause o f the claudication sym ptom s in up to 60% o f cases5160 in som e series. unlike most other com m on causes o f leg pain, popliteal vascular entrapm ent, if not correctly diagnosed and m anaged, m ay well result in occlusion of the popliteal artery w ith the developm ent o f an ischaem ic threat to the lim b .5164 it is therefore im portant fo r all health professionals who deal with patients presenting with leg pain on exercise, to have a good appreciation o f the m anifestations and natural history o f the popliteal vascular entrapm ent syndrom e. failure to make the diagnosis when the condition is the cause o f the presenting sym ptom s may result in the condition progressing to popliteal artery occlusion and even to the developm ent of critical ischaem ia o f the leg. on the other hand, correctly diagnosed and treated, the long-term prognosis is good, with the m ajority o f individuals returning to their norm al sporting activities .51 first described by a m edical student73 in 1879 following dissection o f an am putated leg, popliteal artery entrapm ent syndrom e was considered by early authors to be a rare phe­ nomenon. a fter hamming41 described the first clinical case in 1958, v a rio u s isolated case re p o rts w e re p u b ­ lis h e d .1'3'12-13'20'26'28'33'35'42'44̂ ^^^ in the m id-1960s the term ‘popliteal artery entrapm ent syndrom e’ w as introduced811 to describe the condition. servello71 first drew attention to the reduction in palpable distal pulses frequently observed when patients with this condition perform ed forced plantaro r dor siflexion. biem ans and van b ockel,7 in an extensive review of the literature in 1977, focused attention on the clinical syn­ drom e o f popliteal vascular entrapm ent. early authors believed the popliteal artery entrapm ent syndrom e to be rare ,71217192236374752647274 but it has becom e apparent that the condition is considerably m ore comm on than previously appreciated .8 17-192229-31,35,,5,',7'ss's1's2s;,,ss w hile the incidence of the condition in the general population is not known, bouhoutsos and d askalakis ,8 in the first large series o f cases described, reported an incidence o f 0.165% in young m ales entering the g reek military service. in a post­ m ortem study gibson e t a / .37 found a prevalence o f 3.5%. unfortunately, a substantial proportion o f normal individuals will com press or occlude their popliteal artery with forced plantarflexion or dorsiflexion and will have no sym ptom s, a phenom enon that has precluded the use o f non-invasive tests or duplex d oppler being used as a potential screening tool fo r accurately evaluating the true occurrence o f popliteal artery entrapm ent syndrom e in the asym ptom atic general population .2j4'2127'65r7 the entrapm ent m echanism s has been docum ented to in vo lve the p o p litea l vein in up to o n e -th ird o f cases .7 1936374z-6375 the bilateral occurrence o f the condition was at first assum ed to be rare, but recent literature indicates a high prevalence o f bilateral d isease .12 17 22 28 3764 popliteal artery entrapm ent syndrom e has been reported to occur in m ore than one individual in a fam ily .72 classification and embryology e arly attem pts to classify the various types of popliteal artery entrapm ent syndrom e w ere based on the anatom y observed at operation .847 better appreciation o f the em bryology o f the leg arterial supply, and how the developm ent m ay vary resulting in different types o f vascular entrapm ent, led to a more rational classification based on the developm ental anatomy, with five types of popliteal artery entrapm ent syn­ drom e 6164 currently described. embryology during developm ent in the human, with limb bud rotation m edially and extension of the knee, the medial head o f the gastrocnem ius muscle migrates from its original lateral posi­ tion616 and moves across the popliteal fossa. w ith further developm ent the definitive attachm ent o f the medial head of the gastrocnem ius muscle is to the posterior surface o f the medial fem oral condyle. the embryological popliteal artery in the developing limb bud is the continuation o f the primitive axial or ischiadic artery.6970 the proxim al portion o f the adult popliteal artery develops from the fem oral artery’ 6 by fusion of the develop­ ing fem oral arterial plexus and the axial popliteal artery. the mid-portion of the definitive popliteal artery is directly derived from the rem nant of the axial artery. the prim itive distal popliteal axial artery, lying deep to the form ing popliteus muscle, disappears at about the 2 0 2 2 mm stage o f the embryo, while the definitive distal popliteal artery forms superficial to the popliteus muscle by the fusion o f two new vessels (the new ly anterior and posterior tibial vessels) after the medial head o f the gastronem ius has migrated m edially across the popliteal fossa. during the developm ent of the popliteal fossa, the medial head o f the gastrocnem ius there­ fore m igrates through the popliteal fossa a t about the same time as this rearrangem ent o f the arterial structures.16 classification of popliteal vascular entrap­ ment syndrome if the definitive distal popliteal artery form s before the m igra­ tion o f the medial head, the newly form ed popliteal artery may be sw ept m edially w ith the definitive artery now lying medial to the norm ally placed medial head o f the gastroc­ nemius muscle. this results in the type i popliteal entrap­ ment with a marked medial deviation o f the popliteal artery in the popliteal fossa, both anatom ically and on angiography, as depicted in fig. 1 (type i). c om pression o f the artery then results from pressure by the gastrocnem ius tendon. a lternatively, a p re m a tu re ly form ed d e fin itive distal popliteal artery m ay arrest the medial migration o f the m edi­ al head, resulting in a type ii entrapm ent with the medial head of the gastrocnem ius now more laterally placed than normal. in the type ii entrapm ent, the popliteal artery is m edi­ ally displaced to a lesser degree, and lies deep and medial to the m edial head o f the gastrocnem ius muscle, which attaches more laterally on the medial fem oral condyle or intercondylar area. the artery therefore lies on the medial aspect of, and is entrapped by, the abnormally placed medial head o f the gastrocnemius as demonstrated in fig. 1 (type ii). should m esoderm al rem nants of the migrating medial head persist posterior to the popliteal artery, or should the sports medicine march 2001 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) type i type ii clinical picture popliteal artery medial head o f gastrocnemius muscle a ccessary slip o f gastrocnem ius muscle medial head o f gastrocnemius muscle’ compressed p o p liteal artery popliteus muscle type iii type iv fig. 1. classification o f types o f popliteal artery entrapment syndrome. artery develop w ithin the migrating muscle mass, a type iii popliteal entrapm ent m ay result. here the entrapm ent m ech­ anism is form ed either by fibrous and tendinous bands derived from the rem nants o f the migrating medial head, or more com m only by an abnorm al slip of mature skeletal mus­ cle. these abnorm al additional slips o f muscle tissue may arise from either the medial or lateral fem oral condyles (fig. 1 (type iii)). the definitive popliteal artery may even pass between a double origin o f the medial head o f the gas­ trocnem ius. if the axial artery persists as the definitive distal popliteal artery, it will lie in the prim itive position, deep to the popliteus muscle or fibrous bands ,'10 resulting in a type iv entrapm ent (fig. 1 (type iv)). w hen any type o f entrapm ent m echanism includes or sur­ rounds the popliteal vein as well as the artery, rich ef a /.63 64 have termed this a type v entrapm ent.7,3642 50 a ny of the types of entrapm ent (with the possible exception of type i), may include the tibial nerves resulting in neurological paraesthe siae in addition to claudication as the presenting sym ptom . 15 a type of popliteal artery entrapm ent occurs in the appar­ ent absence of an anatom ical abnormality, termed ‘function­ a l’ entrapm ent.27,65 77 the exact nature of the entrapm ent mechanism rem ains uncertain, but it has been postulated th a t a hypertrophic medial head o f the gastrocnem ius im pinges on the medial and posterior aspect o f the popliteal artery.’ 4,65 up to half o f apparently norm al asym ptom atic indi­ viduals m ay display the phenom enon o f reduced o r abol­ ished p o p litea l a rte ry blood flo w w ith e xtre m e s o f plantarflexion or dorsiflexion against resistance .214 6577 such com pression o f the popliteal artery in the absence of sym p­ tom s should not be regarded as pathological, but when clas­ sica l sym p to m s are a sso cia te d w ith the clinical dem onstration o f functional popliteal vascular entrapm ent syndrom e, the condition probably requires treatm ent. it has been proposed that this ‘functional’ type of popliteal entrap­ m ent be term ed type v i.51 o ccasionally popliteal artery entrapm ent syndrom e may be acquired following vascular surgical reconstruction for fem oropopliteal arterial disease .611 the clinical diagnosis of popliteal artery entrapm ent relies on recognition o f the clinical picture o f calf or foot claudication occurring w ith exercise in the young and often athletic indi­ vidual, som etim es accom panied by paraesthesiae of the fo o t.25,12’5,1863 the syndrom e was previously thought to be more com m on in males. often the initial sym ptom s are precipitated by an episode o f intense physical activity o f the low er limbs, e.g. running a m arathon. s ym ptom s may include cram ping in the calf and foot, coldness, blanching, paraesthesiae and num bness. som e patients m ay present with an aneurysm o f the popliteal artery. any popliteal artery aneurysm in a young patient w ithout a history o f risk factors should suggest the presence o f popliteal vascular entrap­ m ent syndrom e. the ankle pulses are norm al at rest if occlusion has not taken place. untreated, the com pression m echanism fre­ quently results in deterioration of the popliteal artery with the passage o f time resulting in eventual occlusion 13,23 and the absence o f normal ankle pulses. sudden onset o f severe disabling claudication and absent ankle pulses, usually in the absence of risk factors predisposing the individual to ather­ oma, characterise those patients in whom occlusion o f the popliteal artery has taken place due to popliteal entrapm ent. these patients may present with rest pain or ischaem ic ulcers, although the developm ent o f critical ischaem ia with occlusion o f the popliteal artery is rare .51 distal em boli19303768 m ay result consequent on focal throm bus form ation 2 33 a t the site o f entrapm ent or from popliteal aneurysm fo rm a ­ tion 61939,5164 secondary to the entrapment. in pa tie n ts w h o p re se n t w ith classical sym ptom s as described above, the presence of normal pulses at rest w hich dim inish or disappear with forced plantarflexion or dorsiflexion, is diagnostic. a bsent pulses in a young athletic individual w ho presents with claudication should always be considered to be due to popliteal vascular entrapm ent syndrom e unless other pathology is demonstrated. diagnostic modalities the diagnosis o f popliteal artery entrapm ent syndrom e may be confirm ed by d oppler ankle pressures ,8,22,43,5864 pulse volum e recordings, 18 duplex d oppler,24 222354 com puterised axial s c a n n in g ,5966 79 m a g n e tic re sonance (m r) im ag jng m,32,57,77 anc| angiography. all of these m odalities rely on the dem onstration o f popliteal artery com pression with reduced or abolished popliteal artery blood flow occurring w ith forced active plantarflexion or dosiflexion of the foot against resistance. however, the m ost w idely used diagnos­ tic modality continues to be contrast angiography (fig. 2a-d), particularly in order to plan surgery when degeneration, aneurysm or occlusion o f the popliteal artery is suspect ecj 31,38.61 clinical evaluation, non-invasive tests, and angiography all require forced active plantarflexion o r dorsi­ flexion o f the foot against resistance, with the knee fully extended, in order to dem onstrate the abnorm ality if the artery has not yet undergone degenerative changes .27,77 20 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) patients and methods this study presents 51 patients (93 limbs) treated for popliteal artery entrapm ent syndrom e from january 1988 to d ecem ber 1998. all these patients presented with claudica­ tion-like sym ptom s o f the legs causing severe and debilitat­ ing sym ptom s. all patients w ere subjected to clinical evaluation follow ed by d oppler ankle/brachial pressure index m easurem ent and duplex d oppler o f the popliteal artery at rest. patients w ith norm al distal pulses were screened using both popliteal artery duplex d oppler and ankle d oppler recording during active plantarand dorsiflexion against resistance. w here these tests were found to be positive, with reduced or abolished popliteal o r distal flow w ith this m anoeuvre, and in all patients w ith absent ankle pulses or abnorm al d oppler findings at rest, the patients w ere sub­ jected to conventional contrast arteriography, both in the resting and in the forced plantarflexion and dorsiflexion posi­ tions, fo r confirm ation o f the diagnosis. o nly patients with unequivocal evidence o f popliteal artery entrapm ent, either on angiography or at operation, were included in this study. patients w ere not included if their sym ptom s w ere not typical o f popliteal artery entrapm ent syndrom e, and no patient was included in the study on the basis o f positive non-invasive tests alone in the absence o f severe sym ptom s th a t interfered with norm al sporting activi­ ties. results n inety-three instances o f popliteal vascular entrapm ent in 51 individual patients w ere included in this study over an 11 ye a r period dating from january 1988 to d ecem ber 1998. the type o f entrapm ent, presenting features and treatm ent are sum m arised in tables i iv. in 42 patients the sym ptom s and entrapm ent w ere pre­ sent bilaterally, and in 9 patients the condition w as either totally asym ptom atic or not present in the contralateral leg. the mean age o f all the patients w as 34.9 (range 16 55) years. there w ere 58 affected lim bs in male patients (mean age 36.4, range 1 6 5 5 years), and 35 affected lim bs in fem ales (mean age 32.0, range 16 52 years). in 75 lim bs angiographical exam ination confirm ed the presence o f popliteal artery entrapm ent syndrom e and dem onstrated a healthy and patent popliteal artery. in all 75 limbs, the entrapm ent mechanism was released at opera­ tion, usually by m yotom y o f the medial head o f the gastro­ cnem ius m uscle o r abnorm al muscle slips or tendinous bands responsible for the entrapm ent m echanism , and a healthy popliteal artery was confirm ed on exam ination at surgery. all patients treated in this m anner have retained healthy and patent popliteal arteries on follow-up (m edian follow-up 4.7 years, range 1 1 1 years). alm ost without exception, those patients who had previously been com ­ pelled to stop their sporting activities because o f the sym p­ tom s o f popliteal artery entrapm ent, w ere able to resume normal sporting activities following their postoperative recov­ ery. in 2 patients angiography suggested m oderate 'func­ tional' popliteal artery entrapm ent syndrom e bilaterally with a long, diffuse narrowing o f the popliteal artery on plantarflex­ ion, but an otherw ise angiograhically norm al artery at rest. both patients experienced resolution o f their sym ptom s w hen they elected to discontinue their extrem e physical activity, and they rem ain well and asym ptom atic with normal popliteal arteries on duplex d oppler scan after 2 and 3 years’ follow-up respectively. eighteen limbs dem onstrated occlusion o f the popliteal artery o r distal embolisation due to aneurysm al change at the entrapm ent site (13 in males, mean age 33.9 years, sd 11.6 years; and 5 in fem ales, mean age 35.4 years, sd 14.5 table i. presenting features o f 93 lim bs with popliteal artery entrapm ent syndrom e type i ii iii iv fu nction al o r ty p e vi total total in series 5 12 36 8 32 93 o cclusion with seve re ischaem ia 4 5 3 3 3 18 e ntrapm ent cau sin g typical claudication sym ptom s 1 7 33 5 29 75 venous entrap m ent 1 3 6 0 0 10 table ii. a nalysis o f treatm ent o f different types of popliteal entrapm ent syndrom e type 1 ii iii iv fu nction al o r ty p e vi total total 5 12 36 8 32 93 o cclusion 4 5 3 3 3 18 m yo tom y and vein graft 3 4 3 3 3 16 m yotom y only 1 7 33 5 25 71 n o op eration 1 1 0 0 4 6 sports medicine march 2001 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table iii. demographics of 51 patients (93 limbs) presenting with popliteal artery entrapment syndrome 9 5 lim bs in 51 patients m ean age o f 51 patients 34.89 yrs (sd 11.62) 9 unilateral 42 bilateral males females total lim bs 58 35 a ge (yrs) 36.46 32.03 s tandard devia tion (yrs) 11.32 11.46 r ange (yrs) 1 6 5 5 16 52 years). fifteen limbs w ere treated by replacem ent of the occluded segm ent o f the popliteal artery with reversed saphenous vein grafts. e ight instances o f aneurysm s change w ere noted in this group of patients, all associated with type i iv entrapm ents. all 15 remain well and patent on follow -up (median follow-up 4.8 years, range 1 11 years), with 14 o f the 15 returning to norm al sporting activities. one patient required am putation for advanced ischaem ic change at the time o f original presentation, and 1 patient was treat­ ed conservatively because of extensive distal throm bosis of the infragenicular vessels. both o f these patients were found to have hypercoaguable states. no other patients in this series w ho u n d e rw e n t o cclusion developed critical ischaemia. discussion with a greater awareness of popliteal artery entrapm ent syn­ drome we are observing an increase in the frequency of this diagnosis in young adults presenting to the sports medicine specialist.9'0'25,1655 better evaluation of the problem of the ath­ lete with calf p ain'5'485376 by sports m edicine specialists, and improved investigation and screening o f these cases has improved the diagnostic yield in the young patient with unex­ plained calf pain. more than half the patients under the age of 50 years presenting with claudication sym ptom s o f the low er limbs in this and other series were subsequently dem onstrated to have popliteal artery entrapm ent syndrom e as a cause of their sym ptom s.4251 most early reports o f popliteal artery entrapm ent syn­ drom e described patients who had progressed to total occlu­ sion of the artery. the natural history o f the popliteal artery with unrelieved com pression was docum ented to be an aggressive one, and on this basis surgery was advised in all patients with a confirm ed diagnosis.31 the description of pro­ gressive fibrosis of the entrapped vessel wall leading to aneurysm form ation and throm bosis1 15 19 24 64 supports this recom m endation. as the pathology progresses with time, progressive fibrosis and destruction o f the arterial wall occurs,51 first in the arterial adventitia (stage i), then in the media (stage ii), and finally in the intima (stage iii). the im plication is that the degree o f arterial degeneration observed when throm bosis has occurred is so severe that the arterial wall cannot be salvaged. this explains the poor m edium -term patency results obtained after popliteal artery occlusion treated with a lesser procedure such as throm bol­ ysis, angioplasty or throm bectom y with patching. on the other hand, excellent long-term patency is reported after aneurysm repair or occlusion treated by saphenous vein graft. this argues strongly in favour of com plete replacem ent of the popliteal artery, preferably by saphenous vein, when significant degeneration o f the artery or aneurysm formation is noted either on pre-operative angiography, or at the time of operation. although the data in this study dem onstrate no significant difference between the age of those patients presenting with popliteal artery occlusion and those in whom a myotomy only was required, the youngest patients in the series were in most cases athletes with type i or ii entrapm ents, or with tight localised tendinous bands of the type iii and iv entrap­ ments who had undergone popliteal artery occlusion. the patients presenting with occlusion at an older age invariably had m uscular entrapm ent m echanism s of type iii or type vi. this finding suggests that the rate of arterial wall degenera­ tion in popliteal artery entrapm ent syndrom e may depend on the degree of com pression and the m agnitude o f the forces exerted on the popliteal artery by the com pression m echa­ nism. tab le iv. l im b s w ith se ve re is c h a e m ic s y m p to m s d ue to p o p lite a l a rte ry o c c lu s io n c a u se d b y p o p lite a l a rte ry e n tra p m e n t s y n d ro m e presenting with severe ischaemia male female n um b er of lim bs 13 5 a ge of patients (yrs) 33.87 35.40 s tandard deviation (yrs) 11.60 14.49 most cases of type i and ii entrapm ent are easy to diag­ nose on angiography and other imaging modalities. in addi­ tion, the more localised types o f entrapm ent seen with type iii and iv, are in our experience frequently distinguishable from the more diffuse narrowing of the artery found at angiography with the ‘functional’ or type vi entrapment. on the basis o f these observations, it is strongly advised that surgical correction be offered in all cases of type i iv at the time of diagnosis,31 w ithout waiting until arterial degeneration has resulted. the demonstration that the popliteal artery will undergo some transitory com pression or even tem porary occlusion with extrem es of plantarflexion or dorsiflexion in up to half of the normal population, cannot be ignored. the simple dem onstration o f popliteal artery com pression in such stress positions cannot justify operation in patients with otherwise normal anatom y and m inor or no sym ptom s.14-2778 on the other hand, we have in the present series docum ented three popliteal arteries that have undergone occlusion in two patients with a ‘functional’ or type vi sym ptom atic entrap22 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ment, and apparently normal anatomy. the dem onstration that a functional popliteal artery entrapm ent syndrom e may progress to occlusion with the histological picture o f chronic com pression,51 with the degeneration not due to antheroma, justifies a more aggressive surgical approach to sym pto­ matic patients who are dem onstrated to have a functional or type vi entrapm ent. until further research elucidates the clin­ ical significance and natural history o f degeneration of the popliteal artery in the functional type o f entrapm ent in both the asym ptom atic and sym ptom atic patient, the correct m an­ agem ent of this condition must remain controversial. the various m anifestations and types o f popliteal artery entrapm ent syndrom e are much more prevalent than origi­ nally appreciated. this diagnosis should be considered in any patient under the age o f 50 years presenting with typical calf and foot claudication sym ptom s on exercise, particularly if the sym ptom s occur in an athletic individual and partic­ ularly if the normal risk factors for atherom a are absent. the finding o f an isolated popliteal artery aneurysm or isolated popliteal artery occlusion in the young physically active indi­ vidual w ithout evidence o f system ic disease should be con­ sidered to be due to popliteal artery entrapm ent syndrom e unless proven otherwise. the evidence suggests that all patients in whom the type i iv entrapm ent is diagnosed before occlusion o f the artery should receive surgical release o f the entrapm ent m echanism prior to deterioration o f the popliteal artery by repetitive com pression. on the other hand, only patients with a significant and typical history of 2b. a lo c a lis e d e n tra pm e nt o f the arte ry w ith p la n ta rfle x io n due to a lo c a lis e d m u s c u la r ba nd ca u sin g a type iii entrapm ent. fig. 2. some exam ples o f a n g io g ra p h y o f the p o p lite a l artery e n tra pm e nt syndrom e. 2a. a m ed ia l de via tio n o f the arte ry at re s t du e to a type iii a d d itio n a l m u s c u la r head ca u sin g the entrapm ent. 2c. l o ca lise d p o p lite a l arte ry aneurysm fo rm a tio n due to p o p lite a l arte ry e n tra pm e nt syndrom e. sports medicine march 2001 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 2d. the lo n g e r sm o o th e n tra pm e nt often seen w ith the ‘fu n c ­ tio n a l’ o r type vi entrapm ent. sym ptom s should be offered surgical treatm ent for the func­ tional or type vi popliteal artery entrapm ent. once the popliteal artery has undergone occlusion, the evidence sug­ gests that the artery is beyond repair, and it is recom m end­ ed that the artery be replaced, preferably by saphenous vein graft, to ensure optimum long-term popliteal artery patency in these often young and physically active individuals. r e f e r e n c e s 1. abbott wm, darling rc. axillary 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ellingson w, et al. popliteal artery entrapment syndrome. jama 1964; 208: 692-3. 76. turnipseed w, detmer de, gridley f. chronic compartment syndrome. am j surg 1989; 210: 557-63. 77. turnipseed wd, pozniak m. popliteal entrapment as a result of neurovas­ cular compression by the soleus and plantaris muscles. j i/asc surg 1992; 15: 285-94. 78. verhoeven elg, lucarotti me, campbell wb. vanishing popliteal entrap­ ment. e ur j vase endovasc surg 1995; 9: 944-6. 79. williams lr, flinn wr, mccarthy wj, ef al. popliteal artery entrapment: diagnosis by computed tomography. j vase surg 1986; 3: 360-3. sports medicine march 2001 25 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research article creatine supplementation and exercise performance in rugby players r m n kohler (mb chb) south african sports science institute, cape town abstract objective. to determ ine w hether creatine supplem enta­ tion im proves exercise perform ance in rugby players. . setting. buffalo park, east london. subjects. twenty-five club rugby players, after com ple­ tion o f pre-season training. design. field study. seventeen rugby players volun­ teered for the creatine group and 8 rugby players volun­ teered for the control group. the creatine group ingested a creatine m onohydrate supplem ent. the players inges­ ted 20 g of creatine per day for 5 days as a loading dose, followed by a m aintenance dose o f 5 g of creatine per day fo r 79 days. the control group ingested no supple­ ments. subjects had baseline m easurem ents taken before starting creatine supplem entation. players' body mass in kg, 50 m isolated sprint time, and the num ber of sit-ups and push-ups each in 30 seconds, w ere m ea­ sured. the final m easurem ents w ere taken 84 days after starting creatine supplem entation. only players who com pleted the study were analysed. results. fourteen rugby players from the creatine group and 7 rugby players from the control group com ­ pleted the study. the age o f the players in the creatine and control groups was 25.2 ± 3.9 versus 21.3 ± 3.3 years respectively. body mass did not change signifi­ cantly in either group. the body mass changed from 88.8 ± 16.0 to 86.6 ± 14.0 kg in the creatine group and from 87.8 ± 9.9 kg to 87.0 ± 9.7 kg in the control group. isolated sprint perform ance improved significantly in the creatine group from 8.3 ± 0.6 s to 7.9 ± 0.5 s (p < 0.05) sprint perform ance did not change significantly in the control group: 8.4 ± 0.4 s to 8.5 ± 1 . 1 s. the num ber of correspondence: dr ryan kohler 1 rhodesview sawkins road rondebosch c ape town 7700 tel: 082 784 5737 (cell) fax: 021 683 5434 e-mail: ryank@ yebo.co.za push-ups and sit-ups in 30 s increased significantly in the creatine group from 34.7 ± 8.6 to 45.2 ± 6.3 (p < 0.05). and from 30.0 ± 5.9 to 35.0 ± 4.7 (p < 0.05) respectively. in the control group, the num ber of push­ ups did not change significantly: 33.1 ± 9.9 to 33.4 ± 8.5. the num ber of sit-ups increased from 27.3 ± 3.2 to 29.2 ± 2.5. forty-tw o per cent o f the players in the creatine group experienced side-effects when ingesting creatine, compared with the control group w hich had no side effects. conclusion. a fter 84 days o f creatine supplem entation, body mass did not change significantly, but isolated sprint perform ance and the num ber o f push-ups and sit ups performed by the rugby players in the creatine group increased significantly. a large proportion of the rugby players experienced side-effects w hen ingesting crea­ tine monohydrate. introduction creatine supplem ents are being ingested by athletes at all levels of sporting com petition. the use o f creatine is further popularised when anecdotal inform ation of o lym pic athletes reportedly using creatine as a supplem ent are reported in the press.2 athletes perceive that creatine may enhance their specific sports performance. it is estim ated that adenosine triphosphate (atp) and phosphocreatine (per) can sustain very high-intensity exer­ cise for approxim ately 10 seconds.3 theoretically, creatine supplem entation could increase intram uscular per concen­ tration and subsequent atp form ation, prolonging the dura­ tion o f high-intensity physical activity and pow er output.818 overall, creatine supplem entation could be o f benefit to the athlete. o f the many studies published on creatine, many, but far from all, show an im provem ent in perform ance.911 the most convincing evidence for an ergogenic effect is seen in activ­ ities requiring isotonic strength and those that involve repet­ itive bouts of high-intensity. exercise interspersed with short rest periods.34 most of these studies w ere performed under laboratory conditions. there are few studies on the effects of creatine supplem entation on perform ance in the field and during com petitive events. one o f the purported effects of creatine supplem entation is an increase in body mass, particularly muscle m ass.31'33 this may occur in a num ber o f w ays. c reatine, being osmot ically active, could cause an intracellular fluid shift, thereby 26 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:ryank@yebo.co.za increasing intracellular w ater and body mass. it has been suggested that increased cellular hydration and/or increased per may also stim ulate protein synthesis and decrease pro­ tein degradation.2231'33 this effect, however, may not be directly due to increased intracellar pcr or hydration, but due to som e other factor that creatine is affecting. o f the approx­ im ately 20 studies on the effect o f long-term creatine sup­ plem entation on body mass, about 80% show body mass gains.34 the best gains w ere seen in those athletes under­ going resistance training.34 according to available literature, isolated sprint running perform ance in athletes after creatine supplem entation is either im proved26,30 or unaffected.232527'28therefore, the ability o f creatine to improve isolated sprint running performance rem ains controversial. creatine supplem entation may improve high-intensity, short-duration (< 30 s) exercise tasks, as demonstrated in another field study6 where a continuous jum p test fo r 45 s show ed that subjects supplem enting with creatine showed an increase in w ork output during the first 30 s o f the task. accordingly, the aim o f this study w as to determine, in a. field design, w hether creatine supplem entation over 84 days, increased body mass, im proved isolated 50 m sprint perform ance and im proved short-duration high-intensity exercise, as measured by the num ber o f push-ups and sit-ups performed in 30 s each. methods research methods t w e n ty-five rugby players v o lu n te e re d fo r the study. seventeen rugby players volunteered fo r exercise testing w ith creatine supplem entation and form ed the creatine group. these players w ere given 500 g o f creatine m onohy­ drate o f the sam e brand. eight players volunteered fo r exer­ cise testing only and form ed the control group. all players gave inform ed verbal consent to participate in the study and agreed to adhere to the conditions thereof. none of the play­ ers in the creatine group had ingested a creatine m onohy­ drate supplem ent in the previous 3 months. this would be sufficient tim e fo r creatine levels to return to baseline should any player have previously ingested creatine m onohy­ drate. 17,21 none of the players w as vegetarian. this is rele­ vant as vegetarians have virtually no dietary intake of creatine and rely on creatine synthesis in the liver, pancreas and kidneys.11 vegetarians have been shown to have lower plasma creatine levels.10 this does not necessarily mean decreased tissue creatine content.19 theoretically, muscle per levels could be low er in vegetarians. it has been shown that individuals with a 'lo w e r muscle per can have a greater increase in muscle per with creatine supplem entation;14,19 raising the question of greater perform ance benefit.12 all 25 rugby players had com pleted the sam e organised pre-season training and w ere match fit and ready to play their first match. the training schedule fo r the duration o f the study (and fo r the season) fo r all the players w as as follows: practice sessions took place on tuesdays and thursdays, circuit training on m ondays in the gym, and matches on saturdays. exercise at practices involved running and skills training, and in the gym exercise involved using light w eights fo r 15 20 repetitions. baseline testing was performed on all players directly before creatine supplem entation. exercise testing was con­ ducted again after 84 days of creatine supplem entation. param eters to be tested were: body mass in kg, 50 m sprint time, the num ber o f push-ups in 30s and the num ber o f sit ups in 30 s (as a m easure o f short-duration high-intensity exercise). body fat percentage was not measured. environm ental testing conditions w ere consistent. data collection took place in the early evening before rugby prac­ tice. dry, w indless conditions prevailed and the sam e strip of dry grass was used on each occasion. the players were tested barefoot in order to standardise footwear. w hen per­ forming push-ups, the tester placed a fist on the ground to ensure a full range of movem ent. touching the te ste r’s fist with the chest yielded a count. the p la ye r’s feet w ere anchored during the sit-up test and a full range o f m ovem ent w as achieved by the player’s back touching the te ste r’s fist on the ground behind him. three minutes elapsed between the push-up and the sit-up test. creatine and control subjects w ere tested in the evening on the same day. the creatine used in the study w as creatine m onohydrate w ith a percentage purity o f 99.6% gravim etric. the dosing regimen fo r the creatine subjects consisted o f a loading dose o f 20 g/day divided into four daily doses and consum ed over 5 days. this w as followed by a m aintenance dose o f 5 g/day fo r the 79 days. research has shown that creatine uptake into skeletal muscle is enhanced during creatine supplem en­ tation if the creatine is consum ed together with a carbohy­ drate.1620 players w ere instructed to consum e the prescribed creatine am ount mixed with 250 ml o f grape juice, which am ounts to 30 g o f carbohydrate, to optim ise creatine uptake into skeletal muscle.313,16,20 players w ere given 500 g o f crea­ tine fo r the study period accom panied by written instructions concerning dose and frequency o f cre a tin e ingestion. creatine consum ption started imm ediately after baseline testing and continued fo r an 84-day period. players in the creatine group consum ed no other nutritional supplem ents. at the end o f the study period o f 84 days, 14 rugby play­ ers in the creatine group, and 7 rugby players in the placebo group had all their m easurem ents taken and successfully completed the study. two players in the creatine group w ith­ drew because o f w ork com m itm ents, w hile 1 player from each group w ithdrew because of injury. the 14 rugby play­ ers in the creatine group answered a questionnaire that eval­ uated the subjective effects o f creatine supplem entation. statistical methods only the data fo r those players w ho com pleted the study w ere analysed. the analysis o f each group w as done as fo l­ lows: m easurem ents recorded before starting creatine sup­ plementation w ere considered as ‘pre’ creatine effect, and the m easurem ents recorded after 84 days of creatine sup­ plementation as ‘post’ creatine effect. this design allowed for the use o f the dependent f-test or its non-param etric equivalent, the w ilcoxon m atched pairs test, to analyse the relationship between the preand post-creatine results in each group separately. as none o f the variables o r the dif­ sports medicine march 2001 27 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ference o f the relevant variables w ere norm ally distributed, the w ilcoxon m atched pairs procedure w as used. due to the non-norm ality of the data, the mann-w hitney u-test was used to exam ine any relationship and com pare the creatine and control groups. results are expressed as the mean ± standard deviation (sd). the statistical significance was accepted when p < 0.05. results body mass and physical performance in the creatine group, the average body mass decreased from 88.8 ± 16.0 kg to 86.6 ±14. 1 kg and w as not significant. the 50 m isolated sprint speed decreased from 8.3 ± 0.6 s to 7.9 ± 0.5 s (p < 0.05). the num ber o f push-ups per 30 s increased from 34.7 ± 8.6 to 45.2 ± 6.3 (p < 0.05) and the num ber of sit-ups increased from 30.0 ± 5.9 to 35.0 ± 4.7 (p < 0.05) (table i). comparison of the creatine and control groups the 14 rugby players in the creatine group w ere significantly older than the 7 players in the control group (25.2 ± 3.9 v. 21.3 ± 3.3 years, p < 0.05). the players in the creatine group com pleted more push-ups per 30 s at the final test compared with the players in the control group (45.2 ± 6.3 v. 33.4 ± 8.5, p < 0.05). the players in the creatine group com pleted more sit-ups per 30 s at the final test com pared with the players in the control group (35.0 ± 4.7 v. 29.2 ± 2.5, p < 0.05). there w ere no other significant differences between the creatine and control groups. results of the questionnaire o f the 14 rugby players supplem enting with creatine, 42% reported side-effects while ingesting creatine (table ii). there w ere no reported sym ptom s in the control group. these reported side-effects involved the gastro-intestinal tract (4 players), the m usculoskeletal system (1 player) and the cardiovascular system (1 player). these side-effects occurred in different players. the reported gastro-intestinal side-effects w ere experienced during the 5-day loading phase o f creatine supplem entation. the side-effects were diarrhoea, with 1 player reporting colic. one player reported cram ping o f the m uscles in his thighs. one player described increased thirst, a dry mouth and having to pass urine less frequently, indicating possible dehydration. this effect was reported sporadically during the creatine supplem entation period. all 14 rugby players reported that they felt they had an increase in strength, stam ina, recovery tim e and perfor­ mance, with about half o f the subjects experiencing these effects as early as 14 days after starting creatine supple­ mentation. ■ all 14 rugby players considered creatine to be a safe product and would purchase it as an ergogenic aid. the players who decided not to supplement with creatine did so because they believed that it would not improve their performance. discussion isolated sprint perform ance over 50 m showed a significant im provem ent in the creatine group o f rugby players. the increased per stores in the creatine group means that there w ould be more pcr to break down before fatigue starts to set in.815 more atp could be available to enhance muscle con­ traction, and possibly account for the im provem ent in isol­ ated sprint perform ance in the creatine group. these findings are consistent with studies in the literature that used sim ilar sprint distances to test the athletes.2630 the im prove­ ments in perform ance w ere significant in these studies and ranged from 1 to 2%. sprint distances in the studies that did not show an im provem ent in isolated sprint perform ance table i. com parison o f the preand post-test values (mean ± sd) in the creatine and control groups c reatin e (n = 14) c on trol (n = 7) m easu rem en ts pre post pre post body mass (kg) 88.8 ± 16 86.6 ± 14.1 87.8 ± 9.9 87.0 ± 9.7 50 m sprint(s) 8.3 ±0 .6 7.9 ± 0.5 8.4 ± 0.4 8.5 ±1.1 push-ups in 30s 34.7 ± 8.6 45.2 ±6.3 33.1 ± 9.9 33.4 ± 8.5 sit-ups in 30s 30.0 ± 5.9 35.0 ±4.7 27.3 ± 3.2 29.2 ±2.5 table ii. s ide-effects am ong rugby players (n = 14) ingesting creatine system s ide-effects n um ber p ercen tag e gastro-intestinal diarrhoea 3 21 colic 1 7 musculoskeletal cramping 1 7 cardiovascular dehydration 1 7 6 42 28 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) w ere longer and ranged from 60 m to 150 m.2830 the m ajor finding in this study w as a significant im prove­ m ent in the num ber o f sit-ups and push-ups among players in the creatine group compared w ith the control group. supplem enting with creatine assum edly increased muscle per stores in m ost subjects in the creatine group.815 in this study, players in the creatine group w ere able to increase their pow er output during the 30 s duration o f the push-up and sit-up test and delay the onset o f fatigue. however, the study w as non-blinded, and the possibility of the placebo effect does exist in order to account for these significant find­ ings. most studies show that total body mass increases with creatine supplem entation.4,5,7'13'24 this occurs within 5 days during the loading phase and continues during the m ainte­ nance phase.24 initially this is due to w ater retention, and later, with continued creatine supplem entation, possibly to increased m y o fib rilla r protein syn th e s is .21 t his study revealed that the body mass o f players did not change significantly w ith creatine supplem entation. this is not consistent with the data from the questionnaire, which revealed that 65% o f players supplem enting with creatine felt that their body mass had increased and that there w as a change in their physical profile. there may have been a change in their ratio o f fat-free mass to .body mass. dietary factors and calorie intake could also have affected the body mass m easurem ent. one o f the ‘expected’ outcom es o f this study w as that creatine supplem entation would increase body mass. however, this did not happen and the reasons fo r this ergogenic effect w ithout an increase in body mass need to be examined in further studies. the only docum ented side-effect from clinical research studies is that o f w eight gain.31'33 u ndocum ented side-effects o f creatine supplem entation have appeared in lay publica­ tions and in the m edia.1 these include gastro-intestinal dis­ tress, muscle cram ping/m uscle injury and dehydration. the speculated m echanism of stom ach upset is that the m axim um absorption rate o f creatine in the intestine may be exceeded. creatine in the intestine draws w ater into the intestine and could cause loose stools and diarrhoea.34 one could hypothesise that supplem enting w ith large doses of creatine (> 35 g/day) may cause gastro-intestinal symptoms. in this study, it was interesting that players in the creatine group who developed stom ach upset did so during the 5-day loading phase. the most com m only reported anecdotal side-effect is that o f muscle cram ping.129 only 1 player out of 14 reported this effect in this study. it is thought that this muscle dysfunction may be related to electrolyte imbalances in the muscle cell.29 these anecdotal side-effects have been refuted in certain scientific studies.24 despite the reports on side-effects, all subjects supple­ menting with creatine felt that creatine w as a safe product and would purchase creatine as an ergogenic aid. in summary, this study showed that creatine supplem en­ tation significantly im proved isolated sprint perform ance and the num ber of sit-ups and push-ups rugby players could per­ form. c ontrary to results from other studies, body mass did not change significantly. a large proportion o f the players reported experiencing side-effects when ingesting creatine. however, the rugby players did not interpret this as a cause fo r concern and would purchase creatine m onohydrate as an ergogenic aid. thanks to mr j baxter, department of statistics, rhodes university, grahamstown, for statistical analysis of the data. r e f e r e n c e s 1. armour s. creatine: no scare just yet. usa today, 24 april 1998. 2. associated press. creatine naturally boosts performance. 9 may 1993. in: williams mh, kreider rb, branch jd. creatine the power supplement. human kinetics books, 1999. 3. balsom p, soderlund k, ekblom b. creatine in humans with special refer­ ence to creatine supplementation. sports med 1994; 18: 268-80. 4. balsom p, soderlund k, sjodin b, ekblom b. skeletal muscle metabolism during short duration high-intensity exercise: influence of creatine supple­ mentation. acta physiol scand 1995; 154: 303-10. 5. barnett c, hinds m, jenkins dg. effects of creatine supplementation on multiple sprint cycle performance. australian journal o f science and medicine in sports 1996; 28: 35-9. 6. bosco c, tihanyi j, pucsk j. effect of oral creatine supplementation on jumping and running performance. in tj sports med 1997; 18: 369-72. 7. burke l . the complete south african guide to sports nutrition. cape town: oxford university press, 1998: 138-140, 236. 8. casey a, constantin-teodosiu d, howell s, hultman e, greenhaff pl. creatine ingestion favourably affects performance and muscle metabolism during maximal exercise in humans. am j physiol 1996; 271: e31-7. 9. clark jf. creatine and phosphocreatine: a review of their use in exercise and sport. journal o f athletic training 1997; 32: 45-50. 10. delanghe j, de slypere jp, de buyzere m, robbrecht j, wieme r, vermeulen a. normal reference values for creatine, creatinine and carni­ tine are lower in vegetarians. clin chem 1989; 35: 1802-3. 11. derman w, schwellnus m. creatine supplementation in sport. modern medicine 1998; 23: 42-4. 12. ekblom b. effects of creatine supplementation on performance. am j sports med 1996; 24 : s38-9. 13. engelhardt m, neumann g, berbalk a, reuter i. creatine supplementation in endurance sports. med sci sports exerc 1998; 30 : 1123-9. 14. gonzalez de suso jm, prat ja. dietary supplementation using orally taken creatine monohydrate in humans. car news 1994; 6: 4-9. 15. gordon a, hultman e, kaijser l. creatine supplementation in chronic heart failure increases skeletal muscle creatine phosphate and muscle performance. cardiovasc res 1995; 30 : 413-38. 16. green al, hultman e, macdonald ia, sewell da, g reenhaff pl. carbohydrate feeding augments skeletal muscle creatine accumulation during creatine supplementation in. humans. am j physiol 1996; 271: e821-6. 17. greenhaff pl. creatine supplementation and implications for exercise per­ formance and guidelines for creatine supplementation. advances in training and nutrition for endurance sports 1997; 30: 8-11. 18. greenhaff pl, bodin k, soderlund k, hultman e. effect of oral creatine supplementation on muscle phosphocreatine resynthesis. am j physiol 1994; 266: e725-30. 19. harris rc, soderlund k, hultman e. elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation. clin sci 1992; 83: 367-74. 20. haughland rb, chang dt. insulin effects on creatine transport in skeletal muscle. proc soc exp biol med 1975; 148: 1-4. 21. hultman e, soderlund k, timmons ja, cederblad g, greenhaff pl. muscle creatine loading in men. j appl physiol 1996; 81 : 232-7. 22. ingwall js. creatine and the control of muscle-specific protein synthesis in cardiac and skeletal muscle. circ res 1976; 38: 115-23. 23. javierre c, lizarraga ma, ventura jl, garrido e, segura r. creatine sup­ plementation does not improve physical performance in a 150 m race. revista espanola de fisiologia 1997; 53: 343-8. 24. kreider r, ferreira m, wilson m, et al. effects of creatine supplementation on body consumption, strength and sprint performance. med sci sports exerc 1998; 30: 73-82. 25. lefavi rg, mcmillan jl, kahn pj, crosby jf, digioacchino rf, streater ja. effects of creatine monohydrate on performance of collegiate baseball and basketball players (abstract). journal o f strength and conditioning research 1998; 12: 275. sports medicine march 2001 29 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 26. noonan d, berg k, latin rw, wagner jc, reimers k. effects of varying dosages of oral creatine relative to fat free body mass on strength and body composition. journal o f strength and conditioning research 1998; 12: 104-8. 27. peyrebrune mc, nevill me, donaldson fj, cosford dj. the effects o f oral creatine supplementation on performance in single and repeated sprint swimming. j sports sci 1998; 16: 271-9. 28. redondo dr, dowling ea, graham bl, almada al, williams mh. the effects of oral creatine monohydrate supplementation on running velocity. int j sport n utr 1996; 6: 213-21. 29. strauss g, mihoces g. jury still out on creatine use (news). usa today. 4 june 1998. 30. stout jr, echerson j, noonan d, moore g, cullen d. effects of creatine supplementation on exercise performance and fat-free weight in football players during training. nutritional research 1999; 19: 217-25. 31. volek js, boetes m, bush ja, putukian m, sebastionelli wj, kaemer wj! response of testosterone and cortisol concentrations to high-intensity resistance exercise following creatine supplementation. journal o f strength and conditioning research 1997a; 11: 182-7. 32. volek js, kraemer wj. creatine supplementation: its effect on human muscular performance and body composition. journal o f strength and conditioning research 1996; 10: 200-10. 33. volek js, kraemer wj, bush ja, et al. creatine supplementation enhances muscular performance during high-intensity resistance exer­ cise. j am diet assoc 1997b; 97: 765-70. 34. williams mh, kreider rb, branch jd. creatine the power supplement. human kinetics books, 1999. sports medicine in primary care rob johnson sports medicine in primary care provides an easy-to-read refer­ ence for the primary care physician who treats common musculo­ skeletal and sports medicine problems. written by expert clinicians that practice both primary care and sports medicine, this resource contains invaluable information for the non-sports medicine trained physician. features ■ includes only those topics that are most commonly encoun­ tered in the primary care office. ■ the format for musculoskeletal and medical problems is the same from chapter to chapter, helping readers to easily find a specific topic or answer a specific question. ■ summary sites, illustrations, and decision protocols make criti­ cal information easy-to-find. ■ excellent chapter on preparticipation evaluation is included. ■ presents return to activity guidelines. contents: 1. the essential points of the musculoskeletal exam: the focused injury history, the focused musculoskeletal exam 2. preparticipation evaluation, youth and adolescent: history, youth and adolescent: physical exam, adult, 3. the exercise prescrip­ tion: youth and adolescent, adult, 4. principles of training 5. ad­ vising the athlete on nutrition, 6. office based rehabilitation, 7. return to play, 8. the use of nonsteroidal anti-inflammatory drugs and analgesics, 9. office evaluation of minimal brain injury, 10. neck and cervical spine injury, 11. the upper extremity, 12. sports injuries to the lower extremity, 13. back injuries in athletes, 14. chest injury, 15. gastrointestinal problems and abdominal trauma in sports, 16. genitourinary problems, 17. special issues of the young and adolescent athlete 18. special issues of the woman athlete, 19. the mature athlete'20. risk of exercise, 21. the ath­ lete with medical problems, the hypersensitive athlete, the asth­ matic/allergic athlete, caring for the diabetic athlete, the athlete with heart disease, the athlete with chronic obstructive pulmo­ nary disease, seizure disorders and athletes, the role of exer­ cise and athletes in anxiety and depression, the athlete with infectious disease, 22. injection techniques. sept 2000, hardback, 384 pp, 108 ilius., wbs, r550 clinical decision making in sports medicine dinesh kumbhare and john basmajian as more therapies and technologies have developed in the area of sports medicine, the need has grown for scientific evidence and critical appraisal of the effectiveness of specific treatment meth­ ods. this informative text fills this gap by offering discussions on evidence-based sports rehabilitation through a comprehensive and contemporary examination of the subject. it is divided into the fol­ lowing sections: basic considerations which includes cardiovascular considera­ tions, nutritional strategies, dehydration, inflammation, and psy­ chological, sociological and physiological factors in sport therapeutics which covers physiotherapy, chiropractic and al­ ternative treatment approaches special considerations which covers pregnancy, the mature ath­ lete and the paediatric athlete neuromuscular considerations which includes epilepsy, concus­ sion, neuropsychology and neuromuscular conditions regional considerations which covers the shoulder, hand and wrist, lower back, hip and knee, and the ankle. features ■ the focus on evidence-based practice gives practitioners a firm basis for decision making. ■ comprehensively examines clinical decision making in all fac­ ets of sports medicine ■ covers special topics such as neurological issues, arthritis, pregnancy and paediatrics, which are not typically addressed by sports medicine texts ■ the chapter on the aging athlete reflects the current trend toward athletic activity throughout the lifespan ■ applies many of the authors’ principles on decision making in rehabilitation to sports medicine. july 2000, hardback, 432 pp, 55 illus., cl, r499 orders the south african medical association, private bag x1, pinelands 7430. tel (021) 531-3081, fax (021) 531-4126. e-mail: jstrydom@samedical.org prepayment required but not actioned until order despatched. please allow 6-8 weeks for delivery. 30 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:jstrydom@samedical.org letter to the editor drug-free sport to the editor: the south african institute for drug-free s port has noted with surprise and concern the conclusions o f the research article in the n ovem ber edition o f the south african journal o f sports m edicine entitled ‘substance abuse and knowledge thereof am ong elite south african athletes’.1 the use o f drugs to enhance athletic perform ance is against the rules laid down by the governing bodies o f most recognised sports w orldw ide, and elite athletes, particularly those com peting at international level, have an obligation to fam iliarise them selves and com ply with the policies and reg­ ulations o f their governing bodies regarding drugs and sport. relevant inform ation on prohibited and permitted drugs in sport is available from a variety o f sources. most sports fed­ erations are updated annually with the ioc list o f permitted and banned substances in sport, n ocsa produces an excellent booklet which it distributes free o f charge com pris­ ing an alphabetical and therapeutical list o f prohibited, restricted and perm itted drugs in sport, and inform ation can be accessed from the internet, the sa institute fo r drug free s port hotline (021 448 3888, 9.00 a.m. 1.00 p.m. weekdays) and the institute’s website, www.drugfreesport.org.za ignorance of the issues surrounding doping can also no longer be used as an excuse by doctors and pharm acists. it is im portant that they equip them selves with salient inform a­ tion in order to avoid the possibility o f recom m ending or pre­ scribing the use o f prohibited substances to patients involved in com petitive sport. doping substances and m ethods are prohibited in sport fo r various reasons, most notably: (i) their perform ance enhancing effects which contravene the ethics of sport and underm ine the principles o f fair participation; (ii) the harm which they may cause to a com petitor’s health; and (hi) the legal im plications o f using certain substances, such as ana­ bolic androgenic steroids, a schedule v drug. the institute conducts a com prehensive national drug te stin g p rogram m e in a cco rd a n ce w ith international standards fo r doping control (last year 1 600 sportsm en and w om en from 41 sporting disciplines w ere tested both in and out o f competition, and this will be increased to 1 700 tests across 49 sporting disciplines during the current year). the institute has over 50 independent doping control officers nationally, w ho undergo strin g e n t annual training and refresher courses, and in line with international practice, out o f com petition testing will be increased substantially in future. education and the provision o f inform ation are also key elem ents in any national anti-doping strategy. athletes and coaches need to be inform ed o f their obligations under the drug-testing policy o f their sport. school program m es are needed to raise awareness of the issues surrounding doping and drugs in sport and to influence attitudes tow ards health­ ier behaviour. the medical and pharm aceutical professions must be kept inform ed and updated on prohibited and per­ mitted substances and the risks associated with the use of those substances both on and off the playing field. the institute tries to reach all these target markets through a variety o f education and aw areness cam paigns, sem inars, lectures, w orkshops and the distribution o f prom o­ tional and educational material. this year the education pro­ gram m e has been extended to target schoolchildren, as research has produced some disturbing statistics regarding steroid abuse. south africa enjoys considerable status internationally in the field of anti-doping, and is at the forefront o f the latest antidoping strategies and testing m ethods. the institute is am ong a handful o f international anti-doping agencies preparing fo r iso 9002 accreditation this year, and south africa has one of only 27 io c-accredited laboratories w orld­ wide. the institute is represented at m eetings o f the monitoring group on anti doping at the council o f europe; minister n balfour, the m inister o f sport, serves on the executive board of the world anti doping agency (wada); and the c hairm an o f the board o f saids, dr ismail jakoet, was selected as a w ada anti-doping m onitor at the sydney olympics. s port is an im portant part of the south african w ay o f life, and our sporting achievements are a source o f great national pride. doping violates the integrity of sport, carries serious health risks fo r individuals, and prom otes the notion that dis­ honesty can be rewarded. as custodian o f south a frica’s anti-doping programme, the south african institute for d rug-free sport, created by an a ct o f parliam ent in 1977 as an initiative of s port and recreation south africa, is com m itted to prom oting drug-free sport and ethical sporting practices in this country. enquiries: tel. 021 683 7129 / fax 021 683 7274 / email: drugfree@ iafrica.com daphne bradbury general m anager south a frican institute fo r d rug-free sport 1. coopoo y, jakoet j. substance abuse and knowledge thereof among elite south african athletes. south african journal o f sports medicine 2000; 7: 10-13. sports medicine march 2001 31 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) http://www.drugfreesport.org.za mailto:drugfree@iafrica.com letter to the editor early postural correction to the editor: may i draw your attention to the opinion of renowned doctors in the field of sports m edicine, namely that the aetiology o f the m ajority o f sports injuries concerns w idespread postural faults in w eight-bearing joints. w hat is little known, however, is the discovery by neumann-neurode at the turn of the last century that babies like to practise effective rem edial exercises in adult hands, with better and quicker results than are obtained with older children o f any age. since postural faults are frequently inherited, it is not sur­ prising that they are usually noticeable in infancy. the m ed­ ical value of early rem edial exercise is backed up by the positive research results o f p rofessor j trueta1 at the nuffield centre o f orthopaedic surgery in oxford. he proved that infantile partially ossified bones respond more strongly to the stim ulus of exercise and becom e thicker, longer and stronger in less tim e than older ossified bones. that infants have greater capacity for growth, regenera­ tion and adaptation is already com m on medical knowledge and points to the advantage and need to recognise and cor­ rect postural faults in babyhood (club feet and dislocated hips are w ell-know n examples). such corrections are one im portant form o f preventing com m on postural injuries in later years. at present it is im possible to m easure a baby’s postural changes accurately enough fo r research. a t the sam e time the need fo r tim ely correction is so great and the technique o f baby exercise is w ell-enough docum ented that the subject o f o rth o p a e d ia tric m u sculoskeletal correction has now becom e a postgraduate physiotherapy subject in ongoing university courses. i am not alone in thinking th a t early pos­ tural correction will become generally accepted as one means o f preventing comm on sports injuries. for more inform ation contact: agnes w enham (mcsp), tel: (011) 788-5028; or colleen westgate (bsc physio), tel: (011) 787-7293. a gnes w enham parktow n north johannesburg 1. trueta j. r ehabilitation — past and future. british journal o f physiotherapy 1963; nov: 348-50. exercise testing and interpretation a practical approach christopher cooper and thomas storer this book provides a practical and systematic approach to the acquisition, interpretation, and reporting of physiologic responses to exercise. pulmonologists, cardiologists, and sports physicians, as well as respiratory therapists and other allied health profes­ sionals will find this book an indispensable resource when learn­ ing to select proper instruments, identify the most appropriate test protocols, and integrate and interpret physiologic response vari­ ables. the final chapter presents clinical cases to illuminate useful strategies for exercise testing and interpretation. useful appendi­ ces offer laboratory forms, algorithms and calculations, as well as answers to faqs. a glossary of terms, symbols, and definitions is also included. exercise testing and interpretation: a practical ap­ proach offers clearly defined responses (both normal and abnor­ mal) to over thirty performance variables including aerobic, car­ diovascular, ventilatory, and gas-exchange variables. practical, portable, and easy-to-read, this essential guidebook can be used as a complement to more detailed books on the topic, or stand on its own. may 2001, cambridge university press, 246 x 189 mm, 310 pp, 92 line diagrams, 7 half-tones, 67 tables, r450 benefits and hazards of exercise edited by domhnall macauley this internationally contributed book addresses the important issues relating to the long-term benefits and hazards of exercise in the healthy and those with specific chronic condi­ tions. backed up by useful summary boxes and mcqs which add a cme element, this is a comprehensive discussion of an important and current topic in sports medicine. contents: the optimal type of physical activity to enhance health; systematic reviews of physical activity promotion; exercise and psychological well being; exercise and hyperten­ sion; exercise and diabetes; viral illness and sport; sudden death and cardiovascular disease in young athletes; exercise and the older woman; the effect of exercise on reproductive function in male endurance athletes. 1999, bmj, 216 x 138 mm, 284 pp, paperback, r490 orders south a frican medical a ssociation private bag x1, pinelands 7430. tel (021) 531-3081, fax: (021) 531-4126 e-mail: jstrydom @ sam edical.org prepaym ent by cheque or visa/m astercard required. please allow 6-8 w eeks fo r delivery. 32 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:jstrydom@samedical.org instructions to contributors south african journal of sports medicine scope. the south african journal o f sports medicine is an international, refereed journal published for professionals with a primary interest in sports medicine and exercise science prac­ tice. the journal publishes original research and reviews cover­ ing diagnostics, therapeutics and rehabilitation in healthy and physically challenged individuals of all ages and levels of sport and exercise participation. original manuscripts, i.e. those that have not been published elsewhere except in abstract form, will be accepted from all countries and subject to peer review by the editors and editorial board. the south african journal o f sports medicine invites articles for submission from the areas of: (1) diagnosis, treatment, and, rehabilitation of sportand exercise related injuries, (2) medical illnesses induced by or exacerbated by exercise, (3) the relationship between exercise and health, including exercise physiology, (4) the medical care of physically active individuals, (5) sports psychology, (6) sports nutrition, and (7) biomechanics related to sport. articles are invited from with­ in the following categories: original research: clinical research and basic science articles that are clinically relevant. brief reports: clinical studies that are limited in depth or scope but with important findings to report. case reports: reports of clinical observations that have been carefully documented are particularly instructive. additional manuscripts may be submitted, after consulting with the editor-in-chief, in the following categories: letters to the editor: lead editorials: these are short syntheses of data and current thought on topical issues in the field of sports medicine. review articles: these should be concise, in-depth, and well referenced; they should use the principles of critical appraisal (evidence-based medicine). position statements: these succinct but comprehensive documents are typically prepared by a recognised society for the purpose of providing clinical guidelines in important areas of sports medicine. form of manuscript. send manuscripts to professor mike lambert, sports science institute of south africa, p o box 115, newlands, cape town, 8000, tel: (021) 650 4558, fax (021) 686 7530. three copies of each manuscript must be submitted, in english in triple-spaced, typewritten form with a 5 cm (2 inch) left margin. pages should be numbered from the title page. the text of the manuscript should be in the following sequence: structured abstract (including key words), introduction, methods, results, discussion, conclusions, acknowledge­ ments, references, tables, and figure legends. for clarity, sub­ headings are recommended wherever appropriate. in the case of research articles, a short section in the discussion or conclusion should summarise the clinical relevance of the research. the author should retain a copy for reference, as manuscripts are not routinely returned. the title page of each manuscript should include only the article title, the author’s full names (first name, middle initial, last name), academic degrees and affiliations, the name, address, telephone and e-mail numbers of the person to whom proofs and reprint requests should be addressed, necessary footnotes to these items, and a running title not exceeding 45 letters and spaces. indicate specific institutional affiliations of each author. please list degrees or their equivalents. information concerning sources of financial support should be placed in the acknowledgement section. the page following the title page should include a structured abstract prepared according to the detailed instructions listed below. up to six key words should be included at the end of the structured abstract. in the case of research studies, a single statement summarising the clinical relevance should be included. case report. case reports considered for publication must meet the following criteria. they must: 1) report a new syndrome, injury, or medical condition, 2) report a new test or diagnostic technique or method, or 3) draw attention to important clinical complications or problems associated with a common condition. the format of a case report is different from other submitted manuscripts. the differences are as follows; 1) the case must have at least one and a maximum of two figures. 2) the report will be published without an abstract. 3) a maximum of 10 references will be accepted. 4) the subheadings to be used are: introduction, one or two sentences case report(s) discussion 5) the total length of the manuscript must not exceed two type­ set pages (or approximately six typed, double-spaced manu­ script pages) and the editor(s) reserve the right to shorten a manuscript to fit the space requirements. generally speaking, two figures plus references will limit the maximum text to approx­ imately 1 000 words. instructions for structured abstracts. articles containing orig­ inal data concerning the course (prognosis), cause (aetiology), diagnosis, treatment, prevention, or economic analysis of a clin­ ical disorder or an intervention to improve the quality of health care must include a structured abstract of no longer than 250 words using the following headings and information; objective. state the main question or objective of the study and the major hypothesis tested, if any. design. describe the design of the study indicating, as appro­ priate, use of randomisation, blinding, criterion standards for diagnostic tests, temporal direction (retrospective or prospec­ tive), and so on. setting. indicate the study setting, including the level of clin­ ical care (for example, primary or tertiary; private practice or institutional). interventions. describe essential features of any interven­ tions, including their method and duration of administration. main outcome measure(s). the primary study outcome measures should be indicated as planned before data collection began. if the hypothesis being reported was formulated during or after data collection, this fact should be clearly stated. results. describe measurements that are not evident from the nature of the main results and indicate any blinding. if pos­ sible, the results should be accompanied by confidence intervals (most often 95% interval) and the exact level of statistical signif­ icance. for comparative studies confidence intervals should relate to the differences between groups. absolute values should be indicated when risk changes or effect sizes are given. conclusions. state only those conclusions of the study that are directly supported by data, along with their clinical applica­ tion (avoiding over-generalisation) or whether additional study is required before the information should be used in usual clinical settings. equal emphasis must be given to positive and negative findings of equal scientific merit. abstracts for review articles should have the following head­ ings and information: objectives. state the primary objective of the review article. data sources. describe the data sources that were searched, including dates, terms, and constraints. study selection. identify the number of studies reviewed and the criteria used for their selection. data extraction. summarise guidelines used for abstract­ ing data and how they were applied. sports medicine march 2001 33 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) data synthesis. state the main results of the review and the methods used to obtain these results. conclusions. state primary conclusions and their clinical applications, avoiding over-generalisation. suggest areas for additional research if needed. for more detailed information and examples of structured abstracts, please contact the editor-in-chief directly. three copies of original tables, illustrations, and photos must accompany the manuscripts. tables should be typed neatly, each on a separate sheet, with title above and any notes below. explain all abbreviations. do not give the same information in tables and figures. each table should be accompanied by an explicit, detailed legend. illustrations should be submitted unmounted, identified on the back with the author’s name and figure number, and the top plainly marked. if any tables or illustrations submitted have been published elsewhere, written consent to republication should be obtained by the author from the copyright holder and the author(s). graphs and drawings should be 12 x 18” (approximately) glossy prints and should be of professional quality. x-rays or clinical photographs. remove all markings from x-rays before photographing (such as patient’s initials, dates, degree markings). any arrows or lettering must be applied with a professional product. these identifying marks should be large enough to be seen when the photo is reduced. sequences of radiographs should be of the same magnification. the subject should be centred in clinical photographs. crop out extraneous material and background. each figure should have a separate, detailed, fully explicit legend; all sections of the fig­ ure and all abbreviations and symbols used should be clearly defined. colour illustrations will be charged to the authors. details of style. drug names: use generic names only on referring to drugs, followed in parentheses after first mention by a commonly used variant generic. abbreviations. follow the cbe style manual (available from the council of biology editors, 9650 rockville pike, bethesda, maryland 20814, usa) or other standard sources. for abbreviations of journal names, refer to list o f journals indexed in index medicus (available from the superintendent of documents, us government printing office, washington, dc 20402, usa, dhew publication no. (nih) 83 267; issn 0093-3821). references. references are to be numbered alphabetically and cited in text by number. the reference section should be typed double-spaced at the end of the text, following the sample formats given below. journal titles should be abbreviated according to the abbre­ viations approved by index medicus. all single word journal titles should be spelled out. complete information should be given for each reference, including titles of journal articles, names of all authors and editors, and inclusive pagination. it is the author’s responsibility to verify references from the original sources. journal article 1. stratford pw, miserfi d, ogilvie r, binkley j, wuori j. assessing the responsiveness of five kt1000 knee arthrom eter measures used to evaluate anterior laxity at the knee joint. clin j sport med 1991; 1l: 225-8. book 2. antonaccio mj. cardiovascular pharmacology. new york: raven press, 1990. chapter in a book 3. mcginty jb. ligament, bone, and nerve complications. in: sprague nf, iii, ed. complications in arthroscopy. new ' york: raven press, 1989: 87-106. proofs and reprints. proofs must be returned within 3 days of receipt; late return may cause a delay in publication of an article. please check text, tables, legends, and references carefully. to expedite publication, page proofs rather than galleys will be sent to the author, and it may therefore be necessary to charge for alterations other than correction of printing errors. copyright. copyright on all published articles will be held by the publisher. in view of the present copyright law, it is neces­ sary that each co-author of a submitted manuscript sign a state­ ment expressly transferring copyright in the event the paper is published in the journal. a copyright transfer form will be sent to the corresponding author by the office of the editor-in-chief when receipt of a manuscript is acknowledged. instructions for electronic manuscript submission. once the paper has been accepted for publication you will be required to submit an electronic version which matches the accepted paper version. the preferred storage medium is a 31/2 inch disk in an ms-dos compatible format. files should be submitted in one of the following standard word processing formats: microsoft word (preferred), wordperfect, wordstar, or xy-write. each submitted disk must be clearly labelled with the name of the author, item title, journal title, type of equipment used to generate the disk, word processing program (including version number), and file names used. the file submitted on disk must be the final corrected version of the manuscript and must agree with the final accepted version of the submitted paper manu­ script. the disk submitted should contain only the final version of the manuscript. please follow the general instructions on style/arrangement and, in particular, the reference style as given in ‘instructions to authors’. note, however, that while the paper version of the manuscript must be presented in the traditional triple spaced format, the electronic version must be typeset and should not contain any extraneous formatting instructions. for example: use hard car­ riage returns only at the end of paragraphs and display lines (e.g. titles, subheadings). please observe the following conventions concerning dashes: use a single hyphen with a space before it for a minus sign, use a double hyphen (with space before and after) to indi­ cate a ‘long dash’ in text, and a triple hyphen (with no extra space) to indicate a range of numbers (e.g. ‘23— 45’). illustrations and tables will be handled conventionally. however, figure and table legends should be included at the end of the electronic file. non-standard characters (greek letters, mathematical sym­ bols, etc.) should be coded consistently throughout the text. please make a list of such characters and provide a listing of the codes used. 34 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasma’s 9th biennial congress, 6 8 september 2001 9th biennial congress of the south african sports medicine association urgent c all for papers please don'ltorget that w you would like to pre«nl a paper aim® conference. ihe»e ne§d to be wttti us by ihe and of may 3001 form* tor paper* wgi be tent to you wmi ttw regulation totmi wttfch wll be wim you dwrtty. ttnmb muii be lerrt to dr chrttfa janie van rensburg on tax number (012) 386 9901 or u ro ile d to i a*rwcton*<.co.ia sasma immbsfs r1,135.00* non-m«mbere r 1,400.00 * remember mat it only c o iij r220 per annum to |o<n sasma. included in thfe price are all tt» promotion* of member* and iervlo©», a * web a*, the academic expawre. it ti certainly worth the money. application term* can be obtained from sasma head office tel: (012)3869901 or attvnasvelv (012) 362 0712 foe (012) 386 9901 9th biennial congress of the south african sports medicine association early biro special offeri book and pay before 30 june 2001 and only pay r1,06011 sports medicine march 2001 35 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) south african spor s medicine association suid afrikaanse sportgeneeskundige vereening post net suite 226 private bag x 15 menlo park 0102 president sasma dr phiida de jager 1253 south street hatfield pretoria 0083 tel: 012-362 1119 fax: 012-362 0909 e-mail: pdjager@mweb.co.za manco dr philda de jager president 012 362 1119 dr mike marshall 031 303 3894 dr demitri constantinou 011 485 3790 exco members n gauteng jacquie mccord 012 346 6909 c gauteng dr d constantinou 011 485 3601 midlands dr hendrik uys 033 345 0475 natal dr mike marshall 031 303 3874 border dr kevin fricker 043 726 4119 e cape richard stretch 041 504 2584 w province dr jason suter 021 659 5645 free state dr nicolas theron 051 401 2530 nw province dr paul dijkstra 018 294 5159 physiotherapists joyce morton 083 289 7051 biokinetici prof yoga coopoo 083 661 6777 psychologists prof justice potgieter 021 808 4915 nutrition jane downs 082 889 0025 podiatry mr dennis rehbock 082 414 1248 sport science prof m lambert 083 823 4161 secretary: sasma jolene smit postnet suite 226 private bag x15 menlo park 0102 tel: 012-362 1119 fax: 012-362 0909 e-mail: sasma@xsinet.co.za 36 sports medicine march 2001 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:pdjager@mweb.co.za mailto:sasma@xsinet.co.za editorial this edition^ofthe south african journal of sports medicine is devoted to the biennial sasma conference. its contents consists of over 65 abstracts that represent the free communications that have been presented at the conference. publication of all the free communications in this journal is a fs fs m a l a k ’ a r weu as 016 south sp°rts medicine associationvbabjvla). a number of important points come to mind. sasma r is fs the las est im;nber of£ree communications yet presented at a s ^ s m jn6icates ^ s° uth afhcan sp°rts scientists and sports medicine practitioners are willing and able to conduct and present there lesearch. for any growing organization this surely is a healthy sign that t liere is interest and ability despite many constraints, including financial sup­ port for research which unfortunately seems to dwindle. secondly, the journal was in a position to publish the proceedings for the first time. tins means that a research abstract can now be referenced in a scienc t x e i^ ̂ w01 “ “ d * thirdly tribute must be paid to the investigations who will present their research findmgs at the conference for their high quality research. it is encouraging to page through the abstracts and come across many high quali­ ty research projects that surely will stand their ground in any international meeting. many of these studies document novel concepts, treatment modali­ ties and scientific findings. my congratulations to all those who spent endless hours in laboratories and clinics. tins effort must rate as one of the best ways to promote this country to the somewhat 15 international scientists who will attend the conference i am indeed proud to be a member of sasma, and one of the many south african sports medicine practitioners. dr m p schwellnus co-editor: south african journal of sports medicine reô njcgel on-th^spot-paln relief sports medicine september 1996 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) hi-tech therapy for supporting occupational and physiotherapy k in e-tec h multi fu n ction com puterised rehabilitation unit. the m ost effective lo w er extrem ity rehabilitative, sirejigine.u ns and stretching tool on the market! 1. 2 . 3. 4. 5. over 90% of all back injuries occur at the base of the spine. most back supports ride up leaving the base of the spine unsupported. saunders supports won’t ride up and provide continual back support where it s rea y needed most. fir amnnh the nelvis as well as the lower back. * — johannesburg: tel. (o il) 706-7420/1 cape town: c ell. (083) 653-2221 £ £ j -| y e r f l p y durban: tel. (031) 21 7797 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) t in ; soi til african j o u m v l of sports medicine volume 4 number 1 march 1997 editors proj'td n oa k es dr m p schu'ellnus editorial board d r m e moolla d r p de jciger dr ,j s kow no d r p schw artz p r o f r stretch d r c de ridder p r o f b ( 'a n d r e w s d r e u’ derm an mr r 11 far man dr r h mars d r c a noble international advisory board l yle </ m icheli associate clinical professor of orthopaedic surgcrv boston, i sa c h ester r k yle research director, spoils equipment research associates california, i sa p r o f h c wildor hollmunn president des dcnlschen sportarztebiuidcs kolu, west germany h ow ard j green professor, department of kinesiology ontario, canada g eorye a b rooks professor, department of physical education california, usa neil f gordon director, exercise physiology texas, usa edm und r b urke associate professor, biology department, university of colorado colorado, usa g raham n smith physiologist glasgow, scotland contents abstracts submitted for presentation titlepresenting author 1. basson cj 2. beira b 3. boston v 4. branileld as 5. buntnian a 6. carter r 7. chantler i 8. coleman k 9. coleman k 10. cook i 11. coopoo y 12. crons l 13. derman ew 14. derman ew 15. derman ew 16. du plessis a personality and mood states in addicted an noil addicted runners and non-exercisers sternocleidomastoid muscle: mimic of migraine type headaches, dizziness and neurological fallout in post traumatic athletes applied kinesiology for sportsmen are asthmatics fit to scuba dive? inti-avascular dehydration and changes in blood pressure seen during ultradistanee marathon running model for the prediction of optimal st roke mechanisms in swimmers cardiac drift during incremental rowing tests exercise tolerance and skeletal muscle function in patients with carcinoma: effects of exercise training? exercise intolerance and skeletal muscle (sm) abnormalities in patients with chronic obstructive ainvays disease (coad) endurance ratios and total work: are diey valid measures of fatigue resistance? physiological profiles and the establishment of norms for under 21 provincial rugby players in natal. the effect of scheuermann's disease on the total body biomeehanics medication use and abuse prior to international soccer competition comparative effects of zopiclonc and loprazolam 011 hand-eye co-ordination and physical performance in athletes the effects of accbutelol 011 cxercise tolerance, skeletal muscle recruitment and fuel substrate utilisation during exercise of varying intensities knowledge attitude, and nutrient intake of elite six>rtsmen and women (19-25 years old) in potchefstroom continued on page 4 the editor the south african journal of sports medicine po box 115, newlands 7725 production' andrew thomas publishing glcnbarr publishers tv private bag x i 4 parklands 2196 tel: (o il) 442-9759 fax: (011) 880-7898 advertising m arika <lc w a u l/a m lrew t h o m a s reproduction output r e p r o d u ctio n printing h o n o r s on-the-spot-dpin relief the views expressed in individual articles arc the personal views of the authors and are not necessarily shared by the editors, lhc advertisers or the publishers. no articles may be reproduced without the written consent of the publishers. sports medicine march 1997 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 17. du plooy w 18. du toit e 19. du toit e 20. foreman s 21. futre-peters e 22. govender s 23. hattingh jhb 24. hattingh jhb 25. hawley j 26. heystek mj 27. himer m 28. holtzhausen lm 29. holtzhausen lm 30. holtzhausen lm 31. hughes g 32. hughes g 33. hulse b 34. hulse b 35. khan a 36. kiessig m 37. kotras h 38. lambert m 39. lategan l 40. lawther b 41. macfarlane fyv 42. mars m 43. mars s 44. matseke kop 45. moller f 46. nicol j 47. nicol j 48. noakes td 49. olivier s 50. oosthuyse t 51. ramathesele jr 52. scheepers k 53. schwellnus m 54. schwellnus m 55. sibbald h 56. st clair gibson a 57. st clair gibson a 58. stretch r 59. terblanche e 60. terblanche s 61. van heerden j 62. van heerden j 63. viljoen d 64. viljoen d 65. viranna n 66. weston a the carnitine status of athletes preparing for an ultra-marathon of 90km , ' the force absorption and rebound characteristics of cricket batting pads the effect of a low intensity aerobic exercise program on patients using antidepressants pollution, water contact and “dusi-guts” , , , . , low post-race markers of lipid peroxidation in ultramarathon runners with high anti-oxidant status effects of high intensity exercise on lymphocyte dna and plasma vitamin c a conservative approach of grade ii and iii lateral ligament ankle injuries delayed m uscle soreness in sprint athletes . . effect of carbohydrate supplementation on muscle glycogen content and utilisation during one hour cycling performance profile of injuries at the duzi canoe race the response of heart rate and blood lactate concentration to continuos increments 1 running speed. annual incidence and risk factors for rock climbing injuries in south africa anatomical distribution and nature of rock climbing injuries hi south africa electromyographic analysis of upper limb musculature during rock climbing the effect of a static stretch duration and frequency on hamstring musculotendinous the effect of a single static stretching session on hamstring musculotendinous flexibility over effects of sustained high intensity interval training (hit) on exercise performance, skeletal muscle and cardiac function in cardiac rehabilitation patients integrated electromyographic (iemg) activity and cardiovascular response in patients with lower back pain (lbp): effect of sleep surface , metabolic cost of trampoline exercise in relation to treadmill exercise at comparable heart fusafimgine reduces svmptoms of urti in runners after a 56km race the effectiveness of a mental skills training program for eastern province academy cricketers the prevalence of anabolic steroid use in adolescents in south africa isokinetic strength training of the quadri-ceps femoris by means of electrical stimulation the energy cost of running in filed hockey is greater when dribbling a ball mood and performance of cricketers during an international tour community based cardiac rehabilitation programmes a pilot project infra-red laser: an in vitro dosimetry study the risk of human immunodeficiency virus (hiv) transmission in boxing the effect of low-dosage, long-term creatine monohydrate supplementation on the performance of cyclists electromyography and serum electrolytes during recovery from exercise associated muscle cramping . . , serum electrolyte concentration and hydration status in runners with exercise associated muscle cramping pseudoephedrine is without ergogenic effects during prolonged exercise institutional review boards and scientific progress rate of plasma lactate clearance during passive recovery from high intensity exercise the epidemiology of injuries in south african senior school soccer players the effect of endurance training on hypothalamic 5-hydroxytryptamine (5-ht) receptor function . . . abnormal patters of knee medio-lateral deviation are associated with patellofemoral pam m cyclists correcting lower limb kinematics decreases patellofemoral pain ui cyclists post match ecg changes in veteran squash players is it a problem? cardiac performance in veteran squash players and runners during a routine stress ecg, squash and running . energy expenditure of a non-contact boxing training session compared to submaxunat treadmill training the heart rate response of cricket umpires to on-field events an analysis of the hh-vog relationship during free-range exercise in the laboratory effect of prophylactic dose of flurbiprofen on muscle damage and cardiovascular variables during submaximal exercise morphology and intrinsic injury risk in schoolboy rugby muscular “fitness” and intrinsic injury risk in schoolboy rugby the effect of urti on exercise performance in distance runners the treatment of plantar fasciitis and achilles tendonitis by maintaining ankle dorsiflexion using a night splint recovery techniques: a comparison of rest, stretching and massage skeletal muscle enzyme activities in african distance runners 4 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 1 personality and mood states in addicted and non-addicted runners and non-exercisers cj basson, sj anderson, k geils, r farman. university o f natal, psychology department, pietermaritzburg, south africa. the research aimed to examine differences in personality and mood states in groups o f negatively addicted and non-addicted marathon runners, using nonexercisers as a control group. opportunity sampling was used to select 49 regular marathon runners, and 34 non-exercisers. runners were assigned to a non-addicted and addicted group based on their scores on the negative addiction scale o f hailey and bailey. all subjects were required to complete a biographical questionnaire, the poms and the mcmi. data was analysed using anova, and discriminant function analysis. the results indicated the following: the poms vigour sub-scale (a measure o f energy and positive affect), revealed a group difference, with non­ exercisers d isplaying less vigour than the two exercise groups. global mood was found to be more disturbed for the non­ exercisers than for the non-addicted runners. although negatively addicted runners suggested a trend towards higher mood disturbance, this failed to reach statistical significance. the scores on the mcmi revealed group differences for a number o f personality dimensions (avoidant, dependent and schizotypal), as well as for clinical symptom dimensions (anxiety and dysthymia). taken together the results suggest that runners with high negative addiction to running may manifest a tendency towards discrete personality trait pathology that may contribute to their not having the positive mood benefits o f running and exercise. implications for intervention in sport psychology aimed at modifying and accommodating such personality' traits are discussed, as are suggestions for more refined research in the area o f negative running addiction. 2 sternocleidomastoid muscle: mimic of migraine type headaches, dizziness and neurological fallout in post traumatic athletes dr brad beira m. tech: chiropractic in the absence o f hard neurological and orthopaedic findings in patients who present will] migraine type headaches with associated visual disturbances, nausea and dizziness following a fall o f any sporting nature, the reader is well advised to palpate the sternocleidomastoid muscle (scm) for myofascial trigger points. the scm has both a sternal and clavicular division. pain referred from active trigger points in the sternal division may radiate downwards over the upper part o f the sternum. homolateral distribution arching over the cheek, into the maxilla, over the supraorbital ridge and deep within the orbit originate from the midbelly o f this division. discomfort inav be experienced into the external auditor}' meatus on the ipsilateral side. the quality of this pain is described as a deep ache. retropharyngeal pain may also be reported. trigger points in the upper poil ion o f the sternal division refer pain into the occipital ridge behind the ear, to the vertex o f the scalp with associated scalp tenderness. in addition to the nociceptive stimuli, excessive lacnmation, reddening o f the conjunctiva, apparent ptosis with normal papillary size and react ivity and visual disturbances occur on the homolateral side as a result o f autonomic reactivity o f tliis muscle division. visual disturbances include not only blurring but also dimming o f perceived light intensity and sometimes maxillary sinus congestion. myofascial trigger points in die mid level o f the clavicular division refer pain that extends across the forehead to the other side. the upper part o f this division refers pain deep into the homolateral ear and the posterior auricular region. poorly localized pain may be experienced in the ipsilateral molar and cheek. spatial disorientation, postural dizziness and less often vertigo result from proprioceptive myofascial feedback in this division. syncope following sudden turning o f tire head lnay result. disequilibrium may occur separately from or be associated wit h the postural dizziness. sudden falls or ataxia may result. nausea is common but vomiting is infrequent. trigger point examination including methods o f palpation may be «>vered. interventive measures include ischaemic compression, jce and stretch techniques, intramuscular injection. the indications and contraindications o f each technique may be covered. exercises, both in treatment rooms and at home, postural modifications and activity stress.procedures to conclude. 3 applied kinesiology for sportsmen v boston, johannesburg south africa my goal was to find the best techniques for both patient and practitioner in the treatment and prevention o f sport’s injuries. i used applied kinesiology (ak) to achieve this goal. ak is the most holistic system o f healing i have come across, as it com ­ bines the energy balancing methods o f chinese medicine (acupuncture or acupressure), with the structural balancing methods o f osteopathy and chiropractic, plus some spe­ cialised techniques o f its own. also included is cranial osteopathy because the brain is attached to the sacrum via the dura mater. ak is the science o f muscle testing to give die practitioner feedback o f what corrective m ediods are required to the patient. muscle testing again confirms the success or failure o f the technique just applied. this is because each of our muscles are connected to an organ and hence one o f the 14 acupuncture meridians. thus every muscle in the body can be accessed via the acupuncture meridians and odier specialised techniques. this is also true for ligaments, tendons and bones. i have been using the above techniques for a year and have found that i am much more successful hi treating injuries than previously widi conventional techniques. also the injuries don’t re-occur as with previous methods. proof o f this is the fact that previously, trigger points would come back, but now after eliminating them in conjunction with die above methods they don’t. in conclusion both my patients and i have found the above m ediods superior to conventional methods used by me previously, as we have had quicker, more permanent results, and the treatment are not at all painful, unlike some conventional mediods. also, some injuries only respond to the above methods and it is the only system that could clear reac­ tivity. (reactivity is the phenomena o f a tight muscle “bully­ ing” a week muscle thus preventing d ie weak muscle from strengthening. this is spectacular to witness). other advan­ tages are no equipment needed and ak is not restricted to injuries only-it can be used for any medical and emotional problem with out side effects; or just to balance up an athlete for optimum performance. 4 are asthmatics fit to scuba dive? dr as branfield general practice randburg r.s.a to propose that under certain clearly defined criteria (i.e. effective treatment and control o f exercise induced asdima), well controlled asthmatics can dive. to present an approach to recognizing asthma, assessing its severity', and providing effective treatment specifically in divers, both novice and expe­ rienced. to present m ediodology and a clinical approach cur rentfy used in south africa as well as d ie wu\ asthmatic divers or potential divers are approached in other countries. to pre­ sent clear and concise recommendations and a clinical approach to both the novice divers with asthma and experi­ enced divers with asdima. to present acceptable treatment (both acute and preventative) for asthma in a hyperbaric envi­ ronment. to present international standards and approaches to asdima aud diving.in conclusion, d ie key to assessing the asthmatic diver is to exclude exercise or cold air induced bron chospasm and not simply excluding air trapping. a fall in mid expiratory' flow within lialf-an-hour o f stopping exercise is a more sensitive indicator o f asthma than a fall in peak expira­ tory flow or forced expiratory volume in one second, although the forced expiratory volume on one second is a more practical parameter to measure. asthmatic divers should have an annu­ al diving medical that must include adequate pre and post strenuous exercise pulmonary function test. only inhaled cor­ ticosteroids (rather than the less practical sodium cromogly cate) cau be used long term preventative medication in asth m adc divers. asthmatic divers should be encouraged to main­ tain adequate levels o f fitness, warned that asthma may be induced under water and told to avoid pliysicallv demanding dives. sports medicine march 1997 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 5 intravascular dehydration and changes in blood pressure seen during ultradistance marathon running aj bimtman, r carter and g mitchell. department ofphysiology, university o f the witwatersraud, medical school, johannesburg, south africa exercise associated collapse (eac) is caused by post-exercise hypotension. the hypotension is traditionally thought to result from either intravascular voliune depletion or venous pooling. to assess these possibilities s male athletes (age 41 + 7; mean ± sd) were evaluated before and alter an ultradistance marathon for changes in blood and plasma volumes and changes in systolic blood pressuic (si3p), diastolic blood pressure (dbp) and mean arterial pressure (map). change in blood and plasma volume was estimated using changes in haematocrit and haemoglobin concentration. sdp, dbp and map were significantly lower after the race compared to pre-race values (131.3 ± 10,5 vs 106,4 ± 12,2 mmhg, 75,3 ± 7.4 mmhg vs 62,8 ± 11,2 mmhg and 91,8 ± 6,8 mmhg vs 76,6 ± 9,6 mmhg; p<0.05). neither plasma volume nor blood volume was significantly changed (plasma volume increased by 1,4 ± 12,8%; blood volume decreased by 1,9 ± 3,98%). mean cell voliune was significantly decreased (88 ± 2,5 fl vs 87,1 ± 2,3 11; p< 0.05), indicating an intra-cellular to extra­ cellular volume shift. total body water (tbw), body mass and bodv mass index (bmi) were all significantly lower after the race. serum osmolality remained unchanged. there were no statistically significant correlations between changes in plasma volume or in blood volume, and changes in bloocl pressure. this study indicates that athletes who collapse at the end o f ultraendurance races do so as a result of post­ exercise hypotension secondary to venous pooling, and not as a result o f intravascular volume depletion. 7 cardiac i) rut during incremental rowing tests i chan tier and r carter. department o f physiology', university o f the witwatersrand, johannesburg, south africa traditionally, laboratory' rowing tests utilise incremental protocols with workloads varying between 1 and 8 minutes. the heart rates achieved in the tests are used to provide training guidelines for the athletes. inaccuracy in determining training heart rate zones may arise i( insufficient time elapses during each step for a physiological plateau to be attained. thirteen elite rowers (ten males and three females) underwent an incremental test on a concept ii ergometer at 4 different workloads (low intensity, low-moderate intensity, moderate intensity and high intensity). each workload lasted 6 minutes and heart rate was recorded throughout the 3 minute and 6 minute heart rates were significantly different at all 4 exercise intensities (p< 0.05). there was no significant increase in heart rate from the fourth to the sixth minute during the low and high intensity workloads (p< 0.05), suggesting that the heart rate may be approaching a physiological plateau. subsequently, 5 elite rowers (4 males and 1 female) underwent an incremental rowing test on a concept 11 ergometer at 3 stages of moderate to high intensity work, each workload lasting (or 8 minutes. significant differences between the heart rates at 3 minutes mid at 6 minutes, and between heart rates at 3 minutes and at 8 minutes were confirmed (p<0.05). however, for each o( the 3 worldoads, no significant difference was found between heart rates at 6 minutes and at 8 minutes (p< o.oo). this study has confirmed the phenomenon o f cardiac drill during steady state rowing tests lasting between 3 and 6 minutes. however, no significant further drift in heart rate occurs between the 6th and 8th minutes o f an 8-minute stage, indicating a physiological plateau. 6 model for the prediction of optimal stroke mechanics in swimmers dr r oderick carter. department o f physiology; university o f the witwatersrand, johamiesburg, south africa the speed o f forward propulsion in any medium is determined by the |:>roduct o f strok e/stride frequency (sf) and stroke/stride length (sl). sf and sl are inversely related. individual swimmers attain optimal swimming speed through unique combinations ol sf and sl, dependent on both physical mid physiological factors. most swimmers select this combination subconsciously. it may b e advantageous for both training and competition to be able to determine the optimal combination o f sf and sl for an individual swimmer. a mathematical model is proposed in which the results of sim ple field tests may be used to predict the ideal combination o f sf and sl which result in peak swimming speed (pss). maximum ef fort sprints at variable sls and sfs are timed over a known distance. a regression equation is determined for the sf:sl relationship (the “ performance line” ) describing the swimmers unique biom echanical characteristics. a line ol equal gradient (the peak performance line” ) is constructed through the data point with the greatest positive deviation from the “ performance line . differentiation o f the equation defining the area o f a rectangle subtending the “ peak performance line’ to maximise the area o f the rectangle yields the individual swimmer’s pss, and hence the optimal combination o f sf and sl. the proposed model may be o f value in providing swimmers with guidelines for determining their unique optimal stroke mechanics. 8 exercise tolerance and skeletal muscle function in patients with carcinoma: effects of exercise training kl coleman; m emms; td noakes; a smith; ew dennan uct, spoi-ts scicnce institute o f sa, cape town, south africa tli is studv examined changcs in exercise performance and skeletal muscle (sm) structiue and function in 6 patients with carcinoma (ca) following a 12wk training programme, imme diatclv after completion o f chemotherapy treatment. prior to, and after the 12wk training programme patients tuidenvent i) graded exercise to exhaustion on a cycle ergometer for deter­ mination o f peak oxygen consumption (v02 peak) and peak work load (wlpeak) ii) isometric and isokinetic tests of sm strength and endurance iii) sm biopsies for light mid electi on microscopy analysis. results were compared with those obtained from a sedentary', age and gender matched control group (c) tested on initiation o f the study. before training, v02 peak (24.24 ± 2.39 vs 33.02 ± 4.47 m l/0 2/kg/m in; p<0.05) was lower in patients with cancer (ca) when compared with c. however wlpeak (147.50 ± 21.33 vs 185 ± 28.25 \v, p=ns) was not significantly different between groups. peak torque generated in the quadriceps (pktq) corrected for lean thigh volume (ltv) (44.28 ± 4.45 vs 44.88 ± 5.24 nm/l; p=ns) and total power (tp) in a 60 second isometric test o f sm endurance (25.67 + 3.61 vs 40.45 + w/l; p=ns) were not significantly dif­ ferent between groups, however i t tended to be lower in the patients with ca (p=0.08). sm biopsies performed on the ca group did not show significant structural abnonnalities and therefore were not repeated after training. after training, patients with ca decreased their resting heart rate (80.50 ± 4.31 vs 72.67 ± 4.31 b/m hi; p=0.05) and increased their v02 peak (24.24 ± 2.62 vs 28.43 ± 1.88m l/02/k g/m in ) so that dif­ ferences between ca and c were no longer apparent. patients with ca improved wlpeak achieved (147.50 ± 23.37 vs 190.83 ± 27.82 w; p<0.05) and tended to improve tp (25.67 ± 3.96 vs 32.45 ± 4.21 w/l; p = 0.08) after training. the results o f this study suggest that patients with ca have only mildly impaired exercise tolerance and sm structure and function compared to c, these patients show significant physiological improvements after a 12wk training programme, despite recent high dosages o f chemotherapeutic agents. 6 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 9 exercise intolerance and skeletal muscle (sm) abnormalities in patients with chronic obstructive airways disease (coad) kl coleman, r raine; m emms, c st claire-smith, td noakes & ew derman uct, sports science institute ol south africa, cape town, south africa patients with coad commonly experience fatigue and exercise intolerance which is thought to be clue to pulmonaiy factors. however, few studies describe both the structural and function­ al status of sm in patients with coad. this study examines 10 patients with moderate to severe coad and 6 sedentary, healthy control subjects (c) underwent i) graded exercise test to exhaus­ tion for determination o f peak oxygen consumption (v02 peak), peak work load (wlpeak) and peak ventilation (vepeak); ii) iso­ kinetic tests o f sm strength and endurance and ii) sm biopsy for determination o f skeletal muscle structure. vo., peak (18.0 + 1.59 vs 25,40 + 1.15 ml/oo/lcg/min; p<0.05), wlpeak (88.56 ± 21.57 vs 214.17 ± 30.47 w; p<0.001), vepeak (43.95 + 5.40 vs 74.44 ± 8.22 l; p<0.001) and total work performed by the quadriceps 'muscle (twq) in a 60 sec isokinetic test (2113.08 + 376.48 vs 378o.86 ± 364.19 i: ] i< o.ooo) were all lowrer in patients with coad. furthermore, vepeak and peak blood lac­ tate (5.29 ± 1.25 vs 10.71 ± 0.35 p<0.001) w7ere lower in patients with coad when compared with c. peak torque achieved dur­ ing a 30 second isometric test w'as not different between groups (169.92 ± 31.82 vs 217.75 ± 24.17 nm; p=ns) before or after cor­ rection for lean thigh volume (ltv) however, when twq was cor­ rected for ltv values tended to be different between groups (766.73 ± 101.24 vs 978.80 ± 114.78 j/l; p=ns). profound his­ tological and ultrastructural abnormalities were found in all sm biopsies from patients with coad. abnormalities included: type h fibre atrophy, type n fibre predominance, type i fibre hyper­ trophy, necrotic fibres and diffuse mitochondrial abnormalities. these data support the hypothesis that (i) severe sm structural abnormalities are present in patients with coad (ii) functional abnormalities are present in tests o f sm endurance in patients with coad and (iii) these sm structural and junctional abnor­ malities may play a role in exercise intolerance in patients with coad. 11 physiological profiles and the establishment of no r ms for under provincial rugby players in natal coopoo y and govender an. university o f durban-westville, durban, south africa this study obtained data on fitness profiles o f under 21 provincial rugbv players in order that normative tables could be compiled for the forwards, backs and the combined team. the study also provided an insight into the fitness demands of' under 21 provincial rugby players on the basis o f the two major playing units in a rugby game, the forwards and the backs! it further established physiological readiness for senior rugby. the test battery evaluated body composition, flexibility, explosive strength, dynamic strength, cardio-respiratory endurance,anaerobic capacity and agility at the beginning o f a regular season. data from 112 players were categorised in three groups: forwards (57), backs' (55) and the combined team (112) and were statistically analysed. means and standard deviations were computed for all tests. the t-test was applied to the means o f both the forwards and backs for each test to establish the differences. normative tables were established for the forwards, backs and the combined team. in the assessment o f the fitness demands o f the under 21 provincial rugby player, no significant differences were found between backs and forwards, except for percent body fat, lean body mass and grip strength (p<0.05). the fitness demands for backs and forwards appeared to be uniform, suggesting that a single set o f fitness norms will suffice for the whole team. the comparison o f the two sets o f norms for three similar tests indicated that the under 21 provincial norms compare favourably with senior norms. the implications o f the findings on a descriptive basis indicated that d ie under 21 provincial player is physiologically ready to participate at senior level. with careful guidance and mentoring, and o f course, effective training, the potential for participation at national level is evident. 10 endurance ratios and total work: are they valid measures of fatigue resistance? ian cook. university o f the north, sovenga, south africa the puiposc o f tiiis investigation was to evaluate popular methods for determining in \ivo skeletal muscle (quadriceps) concentric fatigue resistance (fr) on an isokinetic dynamometer. the study was divided into two parts. part 1: the records o f one hundred and four patients (82 m, 22 f) were analysed retrospectively. /ml patients had been tested on a cybex 340 dynamometer. the protocol included 4 serial repetitions at 6 0 ’/,, and 20 serial repetitions at 180/s, for unilateral knee ext/flex. only the results o f the tuiinvolved limbs were analysed. patients were placed into four categories: team sports (n = 21); endurance sports (n = 25); strength/sprint sports (n = 10); and non-participants (n = 33). the dependant variable being total work performed in the 20 repetitions (tw20). ptq (n.m) 6 0 /, (p60), ftq (n.m) 1 8 0 /, (p180) correlated significantly (p<0.01) in all groups (0.6244-0.8763 and 0.8836-0.9448 respectively). endurance ratio (er) did not correlate significantly (p>0.05) in any group (-0.0008-0.3919). multiple linear regression (mlr) for pooled data found sample 1 and 2 explained 98.70% o f the variation in tw20. part 2: fourteen patients (7 m, 7 f) were recruited and tested according to the above protocol and an additional protocol10 sets o f l5 repetitions @ 180’/,, with 5 seconds between sets. a logarithmic function | joules = a + b.log (set number)] was used to obtain a fr measure (b; gradient) and strength measure (a; v-intercept). b and a correlated significantly (p<0.01) with p60 (0.9513 and 0./303, respectively). identical correlational patterns as for the retrospective analysis were found. mlr found p180, and sample 2 (joules) explained 99.47% o f the variation in tw20. furthermore, b and a explained 92.79% o f the. variation in tw20. total w'ork for 100 repetitions could be predicted by b and a (99.27%). these data suggest firstly that the popular measure of fr, er, is not a valid measure. secondly, the total work performed in 20-100 repetitious, by itself, is not a measure of fatigue resistance. thirdly, the use o f correct terminology' is advocated. 12 the effect of scheuermann’s disease on the total body biomechanics l crous. department o f physiotherapy, university o f stellenbosch, p 0 box 19063, tygerberg, 7505 during my research to determine w'hether palpation is useful in diagnosing sch euermami’s disease, i realised the devastating effects o f this disease. early recognition and diagnosis is therefore absolutely imperative in order to limit and/or treat the effects it has on the biomechanics o f the body. the pathology o f scheuermann's includes hvpornobility o f 3 to 5 consecutive vertebrae o f the thoracic and/or thoraco-lumbar spine. the wedge shape o f the vertebrae and the resultant kyphosis are clearly visible on x-ray. iliis paper will discuss the consequences o f scheuermann’s disease on the body’s biomechanics. this wedge-shaped, hypomobile area in the thoracic spine results in changes o f the head-on-neck and neck-on-thorax positions resulting in the following problems: tempero-mandibidar dysfunction, headaches and atrophy o f the deep neck flexors. the kyphosis leads to weakness o f the scapular muscles and hvpornobility o f the glenohumeral joint. full range of movement at the glenohumeral joint requires normal mobility o f the thoracic vertebrae. the kyphosis displaces the glenoid which results in glenohumeral joint dysfunction. the above plays an important role in the impingement syndrome with instabilities o f the glenohumeral joint. the centre o f gravity is displaced more anteriorly as a result of the kyphosis, which affects one’s balance in an upright position. disturbance o f balance leads to a decrease in proprioception. in conclusion, it is therefore essential to diagnose scheuermann’s disease as early as possible in order to maintain optimum functional biomechanics o f the body. sports medicine march 1997 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 13 medication use and abuse prior to international soccer competition. ew dennan, h alii, n bengu, w otto, p schwartz, kop matseke & mp schwellnus. university o f cape town & sport science institute o f south africa. despite publicity o f the side effects and possible dangers o f var­ ious medications on the athlete during prolonged vigorous exer­ cise, it is believed that medications are still widely prescribed immediately prior to sporting events. flie purpose o f this study was to determine the patterns o f prescribing medications by team physicians during the 1996 african cup o f nations .soccer tournament. as part o f the fifa & ioc drug testing procedure, the team physicians o f the 15 teams were asked to complete a questionnaire prior to each match. each o f the 16 squad mem­ bers was listed and any prescribed medication or supplement ingested, injected or taken per rectum in the 72 hr period pre­ ceding the match was declared by the physician. 32 matches involving 544 player/match exposures occurred during the tour­ nament. non-steroidal anti-inflammatory medications (nsalds) were the most commonly prescribed medications with 31% o f players having ingested these agents in the period prior to the match. o f the nsalds diclofenac was the most common (19%), followed by ibuprofen (5.6%), indomethacin (3.3%), piroxicarn (2.7%) & aspirin (0.7%). 11% o f players ingest­ ed paracetamol and 2% ingested, polycomponent analgesic preparations in the pre match period. 3.8% o f players were ingesting antibiotic medications. vitamin and mineral supple­ mentation was also very common with 30% o f players ingesting a multivitamin, 11.7% ingesting creatine, 4% ingesting magne­ sium supplementation, 5.8% ingesting inosine, 3% ingesting guarana,l% ingesting alpha-keto glutamate, 0.7% ingesting iron supplementation, & 0.2% chromium picolonate. other medica­ tions declared included nasal decongestants (1.8%), anti-diar­ rhoea medication (1.3%), laxatives (0.4%), anti-histaminics (0.4%) and hydrocortisone cream (0.4%). at four occasions diclofenac and paracetamol was prescribed for the entire squad twice daily, for the three day period between matches. at seven occasions more than one nsaid was prescribed for a player. these results suggest i) prescribing habits vary greatly prior to competition; ii) nsald and analgesic use/abuse is very common during international soccer competition. as these medications are not without significant side effects, improved dissemination o f knowledge regarding the use o f these agents should be directed at both the team physicians and players. 1 4 comparative effects of zopiclone and loprazolam on hand-eye co-ordination & physical performance in athletes. l grobelar, m schw ellnus, c trichard, s calder, t d noakes & ew d erm an*. uct dept, o f s p ort s cien ce & s p ort science institute o f south africa. b enzodiazepines are com m only used by athletes, due to frequent international travel, p re-com p etition anxiety and insomnia. however, little is known about tlieir effects oil exercise perform ance. in dou ble b lin d , p lacebo (p ) con trolled , cross-over trial, tile effects o f z opiclone (z ) and lop ra zolam (l) on p hysical p erform an ce in 12 active individuals w ere studied. subjects ingested eith er i1, z (/.5 in g ) or l at 22 h 0 0 on three occasions w ith a one w k w ashout p eriod betw een trials. eye-liand co-ordin ation tests (a ccuvision 1000), a 30m sprint test, a t-test and a graded exercise test to exhaustion w as p e rfo rm e d 10 hrs after ad m in­ istration. t h ere was a significantly greater hangover e ffe ct 10 hours after ingestion of' l (8 /1 1 subjects) than after ingestion o f z (3 /1 1 ; p < 0 .001 ). subjects w ere significantly m ore alert after ingestion o f p (9 /1 1 ) and z (9 /1 1 subjects) than after l (4 /1 1 subjects; p < 0 .001 ). t he 30m sprint tim e, tim e to com p lete a t-test and th e peals oxygen uptake during graded increm entaf exercise to exhaustion w ere not different foliow ing ingestion o f p, z, and l. however, b o th th e num ber o f correct resp onses during th e accuvision 1000 te st (8 7 ± 1 0 ; 8 7 ± / ; 80 ±18 : p vs z vs l), and th e tim e to fatigue during graded exercise (7 0 5 ± 5 4 ; 68 0±3 8; 669±'50; sec p vs z vs l) tended to decrease follow ing ingestion o f l com p ared to z and p t h e tim e to com p iete a turntable test te n d e d to b e increased follow in g ingestion o f both l and z com p ared to p th esc results suggest: (i) ingestion o f l le a d s to hangover effects .10 hrs aftei ingestion. ingestion o f z however, is w ithout th ese effects: (ii) athletes experien ce significantly greater alertness follow ing ingestion o f z c o m ­ pared witli i,: (iii) w hilst exercise p erform an ce follow in g ingestion o f eith er z or l was n ot significantly altered, tim e to fatigue during incre­ m ental exercise and th e num ber o f co rre ct resp onses during visual m otor tests tend ixrwards im pairm ent follow ing ingestion o f l com pared w ith z and p; (iv) h and-eye c oord ination how ever, ten d s to be im paired follow in g ingestion o f both l and z. 15 the effects of acebutelol on exercise tolerance, skeletal muscle recruitment and fuel substrate utilization during exercise of varying intensities ew derman*, m zambrasis, ja hawley, s dennis, a sinclair-gibson, & td noakes. university o f cape town & sport science institute o f south africa. previous research has indicated that ingestion o f beta-block ers adversely affect the exercise performance tolerance of physically active hypertensive patients. it has been postulated that this effect is due to altered metabolic response to pro­ longed submaximal exercise. the effects o f acebutelol (a), a betal-selective blocker with intrinsic s3tiipathomimetic prop­ erties, on exercise tolerance, skeletal muscle function and metabolism during prolonged exercise are unknown. in a dou­ ble blind placebo (p) controlled trial, we determined the effects o f a (400 mg daily for 7 days) in 7 healthy volunteers on i) cardiorespiratory, ii) plasma lactate (la], glucose [g], and free fatty acid concentrations [ffa] and iii) skeletal mus­ cle electromyographic activity (emg) during incremental sub maximal exercise at 30, 50, and 70% o f their relative peak power output (ppo) at .15, 30, and 45 minutes respectively. thereafter workload was increased every minute by 15 watts to exhaustion to measure ppo. during submaximal exercise, subjects showed significant differences in heart rate (hr) and systolic blood pressure (sbp) (p < 0,01; a vs p). following ingestion o f p, subjects achieved significantly (p<0,05) higher ppo in contrast to a. [la] concentrations between treatments were not different, however lower concentrations o f [g], (p < 0.01) (3,3 ± 0.2 vs. 4.5 ± 0,2 mmol/1) ŵ ere found at rest and during exercise, [ffa] concentrations at rest, 12 min; and 21 inin were similarly lower following ingestion o f a (p < 0 .0 5 ; vs p). no significant difference was found in total carbohydrate (cho) oxidation, glucose oxidation, and estimated muscle glycogen. changes between treatments were observed in rate o f perceived exertion and integrated emg activity after 30 minutes o f submaximal exercise. these findings suggest that i) a is effective in decreasing sbp and h r during submaximal exercise, ii) exercise tolerance is decreased following ingestion o f a, iii) [g] and [tea] are low er during exercise following ingestion o f a, iv) emg and rpe are increased during exercise following ingestion o f a. however, cho oxidation during exer­ cise is unaltered following ingestion o f a. 16 knowledge attitude, and nufrlent intake of elite sportsmen and -women (19-25 years old) in potchefstroom anna du plessis, pu for che, potchelstroom, rsa. little is knowti about knowledge, attitude and nutrient intakes o f south african sportsmen and woman, while nutrient supplementation usage is suspected to b e high. in a cross sectional study including 143 subjects, knowledge and attitude were investigated by means o f validated questionnaires. nutrient intakes w'ere measured by means of a validated food frequency questionnaire. nutritional status was determined by the physical activity index as ŵ ell as anthropometric measurements. a pilot study (n=10) was conducted to determine the reliability o f all instruments used. the results indicated that 80% o f the subjects reflected inadequate diet-related knowledge; only 3.5% subjects reflected a positive attitude towards sports nutrition while the rest showed a highly positive attitude tow-ards supplementation. most o f the subjects did not meet their recommended diet allowances. tlieir nutrient intakes wrere characterized by elevated protein, fat and cholesterol intakes, as we 11 as inadequate carbohydrate intakes. this dietary pattern was related to inadequate micronutrient intakes. anthropometric deviations from published normal ranges occurred more frequently among male sports participants. therefore, this study indicated that elite young sportsmen and women manifested inadequate nutritional status based on inadequate knowledge and negative attitudes towards sports nutrition. the prominent “ compensatory” role ol supplements, underlined the highly underutilized role o f dietitians and the high risk o f suboptimal performance and health hazards, even among elite sportsmen and women in this study. 8 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 17 the carnitine status of athletes preparing for an ultramarathon of 90 km du plooy wj, kahler cp, ‘ kennedy r. departments o f pharmacology and *iiunian nutrition, medunsa, soutli africa. carnitine supplementation before or during exercise failed to show any improvement in exercise performance in humans. a deficiency (48%) in rats did not affect their exercise performance. although data is available for normal subjects and resting athletes none is available for athletes training for a running endurance event o f 90 km. the aim o f this study was to assess the carnitine status o f such athletes over a 45-week period. pen athletes volunteered for the assessment. a group o f 10 sedentary individuals served as controls. blood samples for total carnitine, acyl carnitine, free carnitine, cholesterol, triglycerides and theological parameters were collected every 8 weeks up to 2 weeks prior to the event. body mass index and percentage body fat were also measured. questionnaires reflecting medication, disease and training were collated weekly. the percentage body fat o f two athletes with the highest kilometre training distance decreased with 12 and 13% respectively. the bound carnitine (acyl carnitine fraction) remained constant in the control group. in the training group the acyl carnitine levels increased steadily from baseline 12,48 ± 3,68,(im to reach a maximum o f 23,01 ± 0,01 p,m (p< 0,001) at week 30 and thereafter decreased to 16,53 ± 3,16 |j.m, 2 weeks before the event, with a corresponding decrease in free carnitine from 46,82 ± 10,49 at baseline to 39,28 ± 4,82 at the interval ol biggest change. the decrease in free carnitine and increase in acyl carnitine reflect the demands on the metabolic system to transport acyl groups formed during p-oxidation. it is concluded that monitoring carnitine levels could be used to ascertain the demands on acyl transport during p-oxidalion, but it is unclear which degree o f carnitine deficiency would impede endurance performance. 18 the force absorption and rebound characteristics of cricket batting pads de du toit*, r stretch** and t edwards* * department o f human movement science, university7 o f port elizabeth, * * sport bureau, university o f port elizabeth impact injuries in cricket, although not reaching alarming proportions, are on the increase. the cricket player needs maximum protection against impact injuries from the ball when batting, while still maintaining mobility and reducing die risk ol being dismissed, particularly to bat-pad decisions. a study was conducted to compare the efficiency to absorb impact forces, as well as the rebound characteristics o f four types o f cricket batting pads (pi, p2, p3 and p4) at four impact velocities: slow-medium (s i), fast-medium (s2), fast (s3) and express (s4). the impact forces were measured using the drop test (nigg 1990) where a weighted ball was dropped vertically onto the surface o f the batting pads with the vertical forces measured by a kistler piezoelectric multicomponent force platform type 9281 a l l . the rebound characteristics were determined by measuring the horizontal distance (ni) the ball reboimded o ff the pad when delivered from a bowling machine at the four velocities. a two-way analysis o f variance, with iukey’s method o f multiple comparison, was used to test for significant differences (p<0.05) between the pads at the four impact velocities. when evaluating the impact forces it was foimd that pi provided significantly less protection than all the other pads at the four velocities with the exception of similar results to p4 at s2. further, at si and s3, p2 was significantly better than p3 and p4 and p2 was significantly better than p4. at s2, p2 was significantly better than p2 and p3, while p3 was significantly better than p4. at s4, p2 and p3 showed similar results which were, significantly better than p4. when comparing the rebound characteristics, the results showed significantly smaller rebound distance for pi at all the velocities. the differences in the force absorption and rebound characteristics were as a result o f the differences in the structure and composition of the protective part o f the batting pads. the results show an inverse correlation between the ability to absorb force and the rebound distance after the ball has struck the pads, something that the manufacturers need to address. 19 the effect of a lo w intensity aerobic exercise program on patients using antidepressants de du toit*, s roux** and n hurr** * department o f human movement science, university of port elizabeth ** department o f biochemistry, university of port elizabeth determining the effectiveness o f aerobic exercise in the control of the adipose tissue of subjects utilizing antidepressant medication is due to the common complaint o f undesired mass gain caused by pharmacological treatment for major affective disorders (garland remick and zis, 1988, russ and ackerman, 1988; rang and dale’ 1991 and stimmel, 1992). the aerobic exercise program for the subject on antidepressant medication must be manageable with regards to intensity, frequency, and duration as exceeding the capabilities of die subjects is a certain path to nonadherence (brownell, 1984). factors such as insulin, cholesterol levels and metabolic rate which effect body composition were taken into consideration, while the skinfold, circumference and mass measurements were monitored to determine the effectiveness of aerobic exercise. the intensity o f the exercise program was determined according to the workload corresponding to a respiratory quotient o f just below 0.85. the duration o f the aerobic exercise session was 35 minutes and performed 3 times per week over a period o f 12 weeks. the heart rate decreased consistently (p<0,05), while the blood pressure remained relatively stable. the mean insulin levels of the experimental group decreased though insignificandy 30 minutes after glucose ingestion over the 12 weeks, but the corresponding insulin levels of the control group increased. all the patients exhibit higher than normal "total cholesterol and ldl levels. the study was o f benefit since the exercise group had a mean loss o f 0.086 mmol/1 for cholesterol and 0.007 mmol/1 for ldl while the non-exercise group had a mean increase o f 0.940 mmol/1 cholesterol and 0.64mmol/l ldl. over 12 weeks the control group displayed a constant increase in skinfolds for the triceps, subscapula and medial calf. this emphasizes that the mass gain is an increase in adipose tissue. the non-exercising group also showed an increase o f 4.26cm around the waist over this period. the waist-to-hip ratio increased consistently from 0.94 to 0.97 in the non-exercising group while the waist-to-hip ratio for the exercising group remained constant. this emphasizes the positive effects o f low intensity aerobic exercise for patients utilising antidepressants. 20 pollution, water contact and “ dusi guts” foreman s and mars m. dept, o f physiology, university o f natal medical school, durban, south africa. the msindusi canoe marathon has always been associated with post race illness, “dusi guts” . severe flooding in pietermaritzburg in die week preceding the 1996 race raised faecal coliform counts in the river to high levels. there appeared to be a higher than usual incidence o f race associated illness and infection. the aims o f this study were to determine the incidence of illness and infection, the relationsliip o f water contact with illness, and to provide guidelines for participants o f future dusi’s raced in flood years. four weeks after the race, a questionnaire was sent to all competitors (n = 1302). 652 participants replied (50.1%), o f whom 46% were ill at some stage during or after the race with diarrhoea (149) and infected wounds (113) being most common. 20% o f all respondents required treatment by a doctor. there was no difference in the incidence o f illness or infection between those who fell out o f their canoes during the race and those who did not, nor was there a relationship between the number o f times a paddler fell out and subsequent illness. relative canoeing experience and competitive grading were also not related to illness. while the a grade paddlers fell out significantly less often than the e grade paddlers (p< 0.0001) there was no difference in the incidence o f illness in the grades. the faeeal coliform levels on the race days were up to 30 times higher than the level deemed high risk, in south africa and 150 higher than the levels set by the european economic community. e. coli counts repeated at the same sites during the race showed large daily variation. the accepted maximum illness index for recreational use o f water in the usa is set at 8 illnesses per 1000 swimmers. for this race the index was 460/1000 participants, and 606/1000 competitors who fell out during the race. in summary, in flood years, there is an almost 50% chance o f suffering some form o f illness when participating in dusi and a 20% chance of requiring medical treatment. the pollutant and washing out effect of rain during the race makes pre-race prediction o f pollution levels very difficult. further studies are required to compare these findings with non flood year races. sports medicine march 1997 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 21 low post-race markers of lipid peroxidation in ultramarathon runners with high anti­ oxidant status. em futre-peters*, rd anderson**, ajtheron**, to noakes. ‘ division o f physical education, university of witwatersrand, johannesburg “ institute for pathology, department o f immunology', university o f pretoria ***mrc bioenergetics o f exercise unit in the sport science institute' o f south africa, medical school, university' o f cape tow'll previous studies conducted by our group have show'll a significantly reduced post-race infection incidence following supplementation with anti-oxidant nutrients during the three weeks prior to participation in the 90km comrades marathon. ten successful participants (9 men, 1 woman. x age: 43.4+9.44 yrs) in the 1996 comrades marathon were monitored 18hrs before and within 1 hour following completion of the 90 km running event in order to establish their post-race anti-oxidant status and relate this to markers o f immediate post-race free radical production and die incidence o f infection symptoms occuring during the post­ race fortnight. tweutv-four hour pre-race dietary' recalls and analyses of intake nutritional supplements revealed a mean total dailv vit c intake of430(±378.4)mg on the day preceding the race, while plasma vit c levels rose significantly (p>0.05) from 16.5 (±3.9) pre-race to 21.9 (±5.0)ug.in]1 |mist:-race. pre-race plasma vit e levels (x=8.89 ±1.3)ng.ml1 failed to show' a consistent rise or fall following completion o f die 90 ion event, w hereas pre-race beta carotene levels (x=241.6±78.5ng.ml') dropped significantly (p>0.05) to 231.1 (± 82.8)mg.ml'. despite mi absolute post-race ueutrophilia (x=86.3%) in each o f the subjects, quantification o f lipid peroxide levels by colorimetric measurement of methylene blue in serum samples revealed littie evidence o f the accumulation of tree radicals post exercise. this marker of lipid peroxidation rates did not rise significantiy (p>0.05). the significant, but small rises in c-reactive protein (from 1.3±2.4 mg.l'1 pre-race to 3.4± 2.2m g.l' post race) indicate lesser inflammatory response than previously reported in die literature. only one subject reported symptoms o f upper respiratory' tract infection during the post-race fortnight. this study' reveals a possible protective effect of high pre-race plasma anti-oxidant status against previously reported free radical damage following participation in prolonged competitive running events. 22 effect’s of high intensity exercise on lymphocyte dna and plasma vitamin c. govender sn, bux s, weston a, chuturgoon a, and mars m. department o f physiology', faculty o f mediciue, university of natal, durbau, south africa hartmann et ah recently described a chance observation of dna strand breaks in lymphocytes following short duration, high intensity exercisc to exhaustion in 1 of 3 subjects of differing fitness levels. if tiiis is a consistent finding in trained individuals it mav provide further insight into changes in immune status with overtraining. the aim of this study was to determine die relative frequency o f dna strand breaks in lymphocytes in trained individuals following a single bout of exercise to exhaustion, and to examine associated changes in plasma vitamin c concentration. eleven subjects in regular training were subjected to a ramped treadmill run to exhaustion. they were asked not to exercisc for 48 hours preceding the test and for 48 hours after the test. venous blood samples were collected before and immediately after exercisc, and 24 hours mid 48 hours after exercisc. vitamin c concentration w'as determined by the 2,4 dinitrophenylhydrazine mediod while the single cell gel electrophoresis (scge) assay was carried out on all blood samples to determine dna strand breaks. immediate post exercise samples showed dna damage in lymphocytes of all subjects as evidenced by fluorescent strands of dna outside die cell. no dna strand breaks were observed in subsequent samples. in the pre-exercise sample, dna was visualised as a central core whereas in all samples taken after exercise, dna was found located around the periphery, or confincd to one pole o f the cell. vitamin c levels showed a non significant decrease immediately after exercise which returned to baseline levels after 48 hours. this did no coirelate with dna damage. in summary' exhaustive high intensity' exercise produced changes in dna in lymphocytes lasting 48 hours in all subjects. the different pattern o f dna distribution observed in lymphocytes following exercise has not previously been reported. further studies are required to determine the fate o f the lymphocytes, do they die or do they undergo a reparative process, and is this damage the same in all lymphocyte subsets? 23 a conservative approach of grade h & iii 1ateral ligament ankle injuries. jhb hattingh, dr jj hugo. potchefstroom, s.a. research project over a three year period was done oil grades ii and iii lateral ligament injuries o f the ankle. the aim o f the study was to establish a standardized, dynamic, conservative multi-disciplinary rehabilitation regime. the program followed consisted o f standard treatment and covered the phases from die onset o f the injury until the pat ient returned to competitive sport. the study included 216 patients, 156 male and 60 female, o f ages varying between 16 and 40 years with d ie mean age 22,7" years. sports background: hockey, rugby, squash, netball, cricket, track and field. criteria of acceptance: first injury', no fractures, brustrom grades 11-111, intact inferior tibiofibular joint, medial ligament intact, injury' seen by die medical team-within 48 hours. after thorough initial examination the aim during the first 48 hours was to address swelling, immobilize the ankle and relieve pain. rehabilitation by means o f bodi physiotherapy and bioltinetics w'as divided into a six week period. the treatment w'as divided in three phases for bodi physiotherapy and bioltinetics. during the first phase w'e mainly addressed swelling, pain and activity. in the second phase die emphasis was on mobility. the aim o f third phase was to clear die injured joint and to prepare d ie patient to return to competitive sport. at d ie end o f die third .phase the patient had to pass a sport-specific fitness test. during the study the following complications one noted: 11 gutter syndromes and lour medial tarsal svndroutcs. ten weeks post-injury the patients underwent a final examination where six patients still complained o f pain 111 the ankle during exercise. they were all referred to an orthopaedic surgeon mid eventually all underwent ankle orthroscopy. o f the six, four were diagnosed as suffering from medial tarsal syndromes and two from gutter syndromes. the most important outcome ol tiiis study' wras d ie fact that 97.2% o f die patients returned to competitive sport after six weeks. 24 delayed muscle soreness in sprint athletes jhb hattingh. university o f pretoria, pu for che in diis study the appearance o f delayed muscle soreness w as determined after repetitive sprint events in male and female athletes. 'hie effect o f post-exercise sports massage on die athletes’ lower limbs was also evaluated. kinesiology studies w ere done on day 1 and 5 after the events by making use o f die “ akron” isokinetic apparatus as well as die busco padana to evaluate torque, explosive power and reaction time. flexibility studies were also done with the stretch apparatus. delayed muscle soreness wras established in a mild form, but only in specific muscle groups, namely the prime movers in sprint running. sports massage w'as advantageous, but also more to the prime movers. the massage technique as applied ill this studv seem s to be advantageous to sprint athletes in improving their performance. 10 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 25 effect of carbohydrate supplementation on muscle glycogen content and ui'ilisation during one hour cycling performance john a hawley, garry s palmer, steven c dennis and timothy d noakes. mrc/uct bioenergetics o f exercise research unit, department o f physiology, university o f cape town medical school, south africa. this study compared the effects o f supplementing the normal diets ol 6 trained cyclists with additional carbohydrate (cho) 011 muscle glycogen utilisation during a 1 li cycle time-trial (tt). using a random crossover design, subjects consumed either their normal diet (norm) for 3 d (426 ± 137 g«d 1 cho [5.9 ± 1.4 g«kg ' bodymass, bm]) or additional cho (supp) to increase tlieir intake to 661 ± 76 g»cl ‘ [9.3 ± 0.7 g*kg 1 bm|. supp elevated muscle glycogen content from 459 ± 83 to 565 ± 62 mmol*kg 1 d.w. (p<0.05). however, despite the increased pre-exercise muscle glycogen stores, there was 110 difference in the distance cycled during the tt (40.41 ± 1.44 vs. 40.18 ± 1.76 kin«h ' for norm and supp respectively). during norm, muscle glycogen declined from 459 ± 83 to 175 ± 64 m m ol»kg‘ d.w., whereas with supp the corresponding values were 565 ± 62 and 292 ± 113 nmiol»kg 1 d.w. accordingly, both muscle glycogen utilisation (277 ± 64 vs. 273 ± 114 mniol.«kg ' d.w.) and total cho oxidation (169 ± 20 vs. 165 ± 30g*60 min 1 for norm and supp respectively) were similar. the results o f this study show that when well-trained subjects increase (lie cho content ol their diet for 3 d from 6 to 9 g*kg 1 b.m. there is only a modest increase in muscle glycogen content. as supplementary clio did not improve tt performance, we conductc that cho loading has 110 benefit to performance for athletes who compcte in intense, continuous events lasting i h. furthermore, the substantial muscle cho reserves at the termination ol exercise indicate that muscle glycogen depletion does not determine fatigue at this exercise intensity and duration. 27 the response of heart rate and blood lactate concentration to continttm^ increments in running speed ui jb m hirner, t trowbridge. sheffield university sheffield, england j’ the relationship betw een heart rate and blood lactate concentration in response to incremental increases in running speed, was determined in 10 elite endurance runners. starting at 16.5km /hr or 17.5km /hr the athletes ran continuously until exhausted, 011 a treadmill increasing the speed even' 400 meters by 0.5km /hr to reach a sub maximal speed,depending on ability'. heart rate was recorded every' 15 seconds with a polar 3000 sport tester. blood was taken for lactate analysis alter the athletes had been running at each speed for 60 seconds. all the athletes showed a linear increase in heart rate with increases in running speed. no heart rate deflection point was identified for any athlete. the coefficients o f determination, rr, ranged from (0.81-0.98). the lactate concentration increased as a quadratic function with increase in running speed. no lactate balance point was identified for any athlete. the coefficients o f determination, i~, for the 10 runners ranged from (0.90-0.98). these results were used to link heart rate and lactate through a simple quadratic equation. lactate = a(heart rate)2 +b(heart rate) + c, where a, b and c are constants which vary from athlete to athlete. a simple analysis o f variance showed that the lactate and heart rate relationship can be reliably reproduced using this protocol. 26 profile of injuries at the duzi canoe race dr mj heystek, rek kirkby. department o f family medicine, university' o f pretoria. the duzi canoe race is a three day endurance event over 120 km. the medical support consisted o f a medical tent at the end o f each stage and 3 field stations 011 the route next to the river. the main objective o f this study was to describe the type of injuries sustained by the participants during this event. a prospective descriptive study was undertaken at the 1997 duzi. each participant who reported to the-medical tent or field station were included in this study. over the 3 days 220 participants were treated, 128 the first day, 74 the second day and only 18 011 the last day. the most frequent encountered problems were: 1) abrasions on the hands, arms and legs (n = 55) 2) muscle spasms o f the neck, shoulders and back (n = 44) 3) tendinitis (n = 14) 4) cramps 11 = 13) 5) ankle ligament injuries (n = 11). the most serious injuries were a suspected ankle fracture and a big laceration over the popliteal area. the treatment most frequently used were 1) massage o f painful muscles (66) and 2) cleaning o f wounds/abrasions. over the 3 days 4 partieip;mts were treated for heat exhaustion and dehydration and 1 for heatstress (temp = 38.5’c). the only explanation for the 128 participants treated on the first dav was that 011 the lirst day the temperature was 35‘c, (lie second day was overcast and rainy and the last day partially overcast. 28 annual incidence and risk factors for rock climbing injuries in south africa holtzhausen l-m, pam ' c, constant d, schwellnus m. university o f cape town medical school, south africa. the aim ol this study is to determine [lie composition o f the climbing population in south africa, the prevalence o f injury' amongst this population and some o f the possible risk factors for injury'. data collection, by means o f a self-administered questionnaire, addressed the clim bers’ personal details, grade/experience o f climbing; the hours o f climbing done; climbing style/technique; training sessions; and warm-up and stretch activities. climbers also reported on any injuries sustained during the period january 1992 to december 1992 that could be attributed to tlieir cliinbiiig.two hundred and seven climbers (male 87.4% and female 12.6%) responded (response rate 21%). the annual incidence o f injury was 4 1 ,7%.bivaiiate analysis o f injured climbers (1) versus non injured clim bers (n) indicated a significant difference (pco.os) in those who climb at grades >26 (1 = 8, n = 21 climbers); climb more flays per month ((1 = 9, n = 6 days); climb more hours per day on weekdays (1 = 2, n = 1 hrs); do more hard rock (sport) climbing (1 = 50, n = 32%); do more overhang climbing (1 = 31, n = 18%); do more hours per month 011 formal training (i = 18, n = 11 hrs); do more outdoor training on rock (1 = 31, n = 11%); and spend more time 011 warm-up (1 = 7, n = 4 min) and stretching exercises (1 = 8, n = 4 min). discriminant analysis identified four variables that could distinguish between the injured and noil injured groups: grade o f climbing < 20 (wilkes’ \ = 0.847, p = 0.0000), formal training 011 outdoor rock face (wilkes’ \ = 0.783, p = 0.0000), days per month spent climbing (wilkes’ x = 0.744, p = 0.0000), and percent o f time spent 011 hard rock (sport) climbing (wilkes’ \ = 0.721, p = 0.0000). these lour variables correctly classified climbers as having sustained injuries in 72.8% o f cases. in conclusion we have found the annual incidence o f south african climbing injuries to be 41.7% a figure in keeping with other highly competitive sports. more experienced climbers, climbing at higher grades, more often per week and per month, 011 more off-the-vertical, overhanging outdoor rock walls are more likely to sustain injur)'. sports medicine march 1997 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 29 anatomical distribution and nature of rock climbing injuries in south africa hohzhausen l-m, parry c, schwellnus m. university ol cape town medical school, sovitli africa. the aim o f this study was to investigate the anatomical distribution, nature, mechanism and severity o( injuries in rock climbers. questionnaires were mailed to eighty-five climbers who had indicated in an initial survey that they had sustained injuries attributable to a climbing activity. fifty-one climbers (60%) reported on a total ol 85 injuries. the anatomical distribution o f these injuries was as follows: digits (42%); elbow (11%); shoulder and ankle (7% each); arm, foot and back (4.7% each); forearm (3.5%); vertebral column, pelvis, thigh, knee, wrist and hand (2.4% each). the nature o f these injviries was o f sudden onset in 60% of cases and of gradual onset in 40% o f cases. very few sudden onset injuries represented fractures (8%) or dislocations (5.5%). these bony injuries were sustained during falls from the climbing surface. the majority o f injuries were reported as muscle strains and tears, ligament sprains, and tendonitis. sixty' seven percent of climbers with sudden injury' indicated that a specific climbing move could explain the mechanism o f injury'. severity ol these injuries, as assessed by climbing day's lost, averaged 52 days (std = 84, range = 0 400 days). we conclude diat injuries sustained whilst climbing affect mainly the upper limb (73%) with d ie digits (42%) and the elbow (11%) predominating. they are more likely to be acute than chronic injviries and more commonly involve sofl tissues than bones. in most cases o f sudden onset injury, the mechanism o f injury can be explained by a specific climbing manoeuvre. the range of injury severity is very wide with most injuries averaging 7 weeks in lost climbing days. this figure is in keeping with time to healing for most soft tissue injuries. 30 electromyographic analysis of upper limb musculature during rock climbing ilollzliauseii l-m, o’shaughnessy k, bridger b and schwellnus m. university o f cape town medical school, south africa. the aim o f this study was to determine the electromyographic activity profiles o f six forearm muscles commonly used during sport rock climbing. six intei-mediate (>grade 20) male climbers volunteered for die study. two indoor artificial climbing w'alls were erected one oil the vertical and one angled at 30' o ff the vertical. climbers were tested oil the two w'alls using four different handhold types most commonly used by climbers : an open grip, cling (crimp) grip, two-finger pocket grip and an undercling grip. electromyographic (emg) data were recorded during a 30 second period using an em8 emg unit linked to a personal computer with custom written software. two groups o f three muscles each w'ere chosen for analysis: group 1 = brachialis (b), 11 ex or digitorum superficialis (fds) and pronator quadratus (pq); group 2 = flexor carpi ulneris.(fcu), brachioradialis (br) and extensor digitorum (ed).tlie table below summarizes the emg results o b t a i n e d : vertical wall musclc o|>cti crimp pocket undcrcling overhang wall open crimp |kk.:kel undcrcling. b 71 ±36 61 ±30 71±33 66± 39 28±17 57±22 69+30 51±36 pq 59±34 53±40 71 ±37 58±40 46±31 41 ±31 34±29 54±35 eds 51±31 54±29 75±36 57±20 41 ±17 56±25 8o±30 52±23 fcu 82±23 82±20 47±30 45±30 66±22 80±16 59±34 +is br 47+33 46±35 66±24 65±23 41±32 50±29 68±38 58±12 ed 59±37 57±34 41±30 44±21 50±38 50±31 3!+1% 11±11 31 the effect of static stretch duration and frequency on hamstring musculotendinous flexibility g hughes, m schwellnus facsm, university ol cape tow'll medical school a study was undertaken to investigate the effect o f different durations and frequencies o f static stretch on hamstring musculotendinous flexibility. ten subjects were studied under two conditions with one limb having the experimental stretch procedure performed on it, while the opposite limb acted as the control. the duration o f static stretch was determined by comparing die effect ol 10, 20, 30, 60, 90, 120 and 240 second duration stretches on hip joint range o f motion (rom). the end point o f rom was determined using a previously validated technique which defines die end point by a sudden increase in surface emg activity. the number o f stretch repetitions (frequency) w'as determined by comparing d ie effect of 1, 2, 3, 4, 5, 7 and 9 repetitions o f a 30 second stretch each on hipjoint rom. a significant (p<0.01) increase in hip flexion rom from baseline (measured 5’ ) was documented after all the durations o f stretch except in the 10 second static stretch duration (0.9 ± 2.8'). no significant differences (p>0.05) were observed between the 30, 60, and 90 seconds durations, but these durations resulted in significantiy (p<0.05) larger increases in rom than the 120 and 240 second durations. a significantly (p < 0 .0 1 ) larger increase in rom was observed alter 2 repetitions (9.8 + 2.3') compared vvitii 1 repetition (6.5 + 2.0‘ ). a significantiy (p<0.01) larger increase was also observed with 3 repetitions (12.8 + 1.8') compared with 2 repetitions (9.8 + 2.3'). there were no differences (p>0.05) between 3, 4, 5, 7 and 9 repetitions. in conclusion, these studies indicate that the ideal static stretch session consists o f a stretch o f 30 to 90 seconds duration, repeated more tiian 3 times. multiple linear regression analysis was done to determine w'hedier or not significant relationships existed between the grip type and level of muscle activity and the type of wall (overhang or vertical) that was climbed, hi die first analysis climber 1 on wall 1 (vertical) using muscle 1 (brachialis) on grip 1 (open grip) w'as established as the constant dependent variable. the four independent variables were: w'all (2 levels); climber (6 levels); muscle (6 levels) and grip type (4 levels). the four variables, without any interaction terms included, accounted for 28% (r=0.53) o f the variance o f the dependent variable (f=7.57, df=14 and 287, p<0.001). when the climber muscle interaction (25 terms) was added to the model, 46% (r=0.678) o f die variance o f the dependent variable could be accounted for (f= 5.44, df=39 and 287, p<0.001). this suggests that differences in technique between different climbers are possible even when the same grip is used. when muscle-grip interaction (54 parameters) was also added to the model, 56% (r=0.749) o f the variance o f the dependent variable could be accounted for (f=5.44, df=39 and 287, p<= 0.001). the interaction between muscle and w'all made no meaningful improvement to the model. in conclusion, high levels of electrical activity were found in d ie forearm muscles under all conditions tested. the regression analysis revealed that forearm muscle emg in rock climbing is influenced by the type o f grip used, the muscle being sampled, die individual climber and the wall. 12 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 32 the effect of a single static stretciiing session on hamstring musculotendinous flexibility over 24 hours g flughes, m schwellnus facsm, university ol cape row'll medical school the aim o f this study was to determine the retention of increased range o f motion (rom) over 24 hours after a single static stretching session o f 30 seconds duration and repeated 3 times. hip joint rom (in degrees), using surface emg activity to determine the end-point, was measured before die stretching session, immediately after the stretching session, and at 1, 2, 3, 4, 5, 6, 12 and 24 hours after the stretching session. analysis o f results showed a significant difference (p<0.05) between the pre-stretch rom (92 ± 12‘) immediately after (106 ± 12") and at 1 (105 ± 12‘), 2 (104 ± 13‘), 3 (104 ± 11 ) and 4 hours (103 ± 11') post stretch. a significant difference (p<0.05) was also found between the immediate post stretch rom (106 ± 12‘) and the 12 (94 ± 12‘) and 24 hours (93 ± 12‘ ) post stretch measurements. these findings indicate that increased rom after the optimum static stretching session was retained for only 4 to 6 hours. in conclusion, this study indicates that after a static stretch session (30 seconds x 3 repetitions) the increased rom is retained for up to 6 hours only. stretching programs, using the static stretching technique, should therefore be modified so that stretching sessions are conducted 3 to 4 times per day. 33 effects of sustained high intensity interval training (hit) on exercise performance, skeletal muscle and cardiac function in cardiac rehabilitation patients bl hulse, ew derman, ev lambert, & td noakes. uct bioenergetics o f exercise research unit, sport science institute o f south africa, cape town. this study compared the effects o f the addition o f a 10 wk hit program o f cycle ergometer training @ 80-90% v0aillllx (hit; n=9), to continued conventional aerobic exercise @ 50-70% v02_ (cont; 11=8) on maximal (max) and submaximal (smx) exercise performance, skeletal muscle strength and resting cardiac function, in 17 aerobically trained patients participating in a cardiac rehabilitation program. before and after intervention both groups performed: i)graded exercise to exhaustion, for determination o f v02ranx and peak power output (ppo); ii) a six minute walk test (6wt) for distance covered; iii) tests o f isometric and isokinetic skeletal muscle function (smf) & iv) echocardiography for determination o f ejection fraction (ef) and left vent ricular mass (lvm). at baseline, all parameters were similar between hit and cont groups. after intervention, ppo increased by 17% (130 ± 12 vs 156 ± 12 w; [mean ± sem i, p <0.005) in the hit group but was unchanged in die cont' group (140 ± 14 vs 136 ± 14 w). similarly v0o„lax increased by 18% after hit (24.5 ± 1.9 vs 29.7 ± 1.9; uilo^kg m in 1; p<0.05) iu the fi1t group but was unchanged in the cont group (23.3 ± 2 vs. 24.2 ± 2.3 mlos kg min '). distance covered in the 6wt increased after hit (11%; 635 ± 27 vs. 713 ± 27 ni; p<0.01), but was unchanged in the cont group (584 ± 45 vs. 577 ± 28 m). ef, lvm and smf did not change in either hit or cont groups. these results suggest that hit resulted in improved max and smx exercise performance, which could not be attributed to enhanced resting cardiac function or smf. these adaptations exceed those seen in the healthy athletic population performing hit. 34 integrated electromyographic ofm f", activity and cardiovascular response mv patients with lower back pain (lbp)efffct n p sleep surface. bl hulse, a st clair gibson, td noakes & ew derman. uct bioenergetics o f exercise research unit, s)x>rts science institute o f south africa, cape town. we have recently show'll that patients with chronic lbp have decreased iemg activity o f the erector spinae muscles, hnver heart rates (iir) & increased perception o f comfort (roc) when lying on a locally designed, triple density, contoured, lumber body support (lbs) compared with a regular flat sur­ face mattress (cm). in order to determine a mechanism for these effects, we studied patients with lbp after an acute, ran­ dom order, 30 min exposure to 4 sleep surfaces: lbs, cm, a low density, flat, egg box foam mattress (ebm) and a polystyrene shape mould (pm), identical to the shape o f the lbs. patients ware divided into 2 groups: i) lbs, ebm & cm (n=10) & ii) lbs, pm & cm (n=10). each patient acted as h is/her own control. recordings o f iemg activity', hr & roc were measured at 5 min intervals for each patient. at baseline, patients w'ere included only if deep palpation o f the erector spinae musculature clicited pain. after acute exposure to the lbs, average hr i by 13 b/m in over d ie 30 min period (58.72 ± 3.87; b/m in; p<0.05), but was unchanged for the ebm and cm groups (62.83 ± 4.02; b/m in) & (62.89 ± 3.78; b/m in). average roc reported after acute exposure to the lbs wras sig­ nificantly improved (1.86 ± 0.33; p<0.05), compared to roc after exposure to the ebm (4.22 ± 0.43) & cm (4.6 ± 1.67). average iemg measurements w'ere significantlv reduced oil the lbs (3.88 ± 0.76; niv; p<0.05) compared to die cm (13.81 ± 2.16; niv) and ebm (16.44 ± 2.86; mv). ii) in die second group, hr 4significantly after exposure to d ie lbs, (60 ± 2.3; b/min; p<0.001), while there was no significant change for pm (66 ± 2.9; b/m in) & cm (68.15 ± 2.97: b/m in). roc was sig nificandv improved on the lbs (1.83 ± 0.18, p<0.01) vs pm (5.6 ± 0.78) & cm (4..1.3 ± o.o6). average iemg measurements w'ere signilicandy reduced on die lbs (3.83 ± 0.72; niv; p<0.05) vs cm (14.35 ± 5.66; niv) & pm (27.6 ± 9.24; mv)! these residts suggest that patients with lbp have i iemg & h r measurements & improved roc wiien lying on a lbs com ­ p ared w idi a cm; ebm and pm. these findings indicate that die effect o f die lbs is likely due to a combination o f both its density' and contour features. 35 metabolic cost of trampoline exercise in relation t o treadmill e xercise at comparable h e a r t rates a klian, a k weston, m mars, d epartm ent o f physiology, university of natal m cd ical s chool, durban. south africa exercising 011 th e mini-lraiiipolinc lias b e co m e increasingly popular particularly in the hom e environment.. however quantification o f exercise intensity is difficult. one p ossible m ethod would b e the use o f heart rate bu t the relationship betw een heart rate (h r ) and oxygen consum ption (vo») during m ini-tram poline exercise is not clear. t h erefore the aim ol the current study was to elucidate the relationship betw een h r and v 0 2 during m ini-tram poline exercise and to com pare the sam e relationship during treadm ill running over a com parable range ol heart rates. a 11 additional aim was to investigate the c f f e c t o f d ie h eigh t o f leg lift at a given; com m only used step rate. subjects (n =1 7) were m ale cage range 18-30) and all had undertaken a fam iliarisation session prior to com p letin g th e test. w orldoads 011 the tram poline were 100, 120, 160 and 200 s t e p s / m in with a 15cm leg lift and a final w orkload at 120 stcp s/m in with a 9 0 ‘ leg lift, with pace maintained by m etronom e. 1 lie first w orldoad was m aintained for 5 m ins and all subsequent w orkloads for 3 m ins, will] recordings m ade for analyses in th e last 30 sec ol caeli w orldoad. five treadm ill w orkloads were selected for each subject to give a sim ilar range o f heart rates to those achieved 011 the niini-trainpoliiie. im m ediately after the 5th w orkload 011 the treadm ill, subjects continued to exhaustion for determ ination o f p eak v 0 2. t h e relationship betw een v 0 2 and mr 011 tiie treadm ill was linear as d escribed elsew h ere, with tlic equation voo=20.2hr 1070, whilst, the equation o f th e relationship betw een v o , and h r for tram poline exercise was exponent.ial (vo..=441 c " " |,imi') show ing a p ronounced elevation iu h [{prior to an elevation in vo-,. t he m ean v 0 2 w h ilst stepping at 120 ste p s/m in with a leg lift o f 90" was significantly high er than with a leg lift o f 15 cm (2 .1 0 1/inin vs 1.97 1/min, p< 0.001). t h e results o f this study indicate the heart rate is not mi accurate m eth od o f m onitoring c x cr c is c intensity during tram poline e x ercise and that the degree o f leg lift is crucial in prescribin g exercise intensity' during such exercise. sports medicine march 1997 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 36 fusafungine reduces symptoms of upper respiratory tract infections (urtd in runners after a 56km race m schweuiws facsm, m kiessig, w demiaii facsm, t noakes facsm. university o f cape town,'south africa. the effect o f fusifungine, a topical anti-infjammatoty/anti bacterial nasal/oral sprav, 011 the incidence ol symptoms of upper respiratory7 tract infections (urtd in the 9 days following, a £>61011 running lt o ii was studied. male runners (n=96) with a 42km tune of <3hrs, with no history of allergy, and with daily intakes of ■0 < looomg-vitamin c, ii) < 18mg beta carotene, and hi) < 400 lu vitamin e were recruited. prior to the race, subjects were instructed on the proper use o f the medication (4 spray's into each nostril and the throat 4. times daily) and then randomly allocated to either a group receiving fusafimgine (f:n=48) or a placebo ( p :n = 48) in a double blind manner. subjects completed a daily logbook detailing symptoms [runny nose (rn), b l « * ecl nosf all nasal symptoms (n = rn+bn), sore throat (si ), and all urt symptoms (urts = rn+bn+st), in die 2 day's before die race, the first 3 days after, and die 4-9 days after d ie race. au the symptomatic subjects underwent medical evaluation. throat swabs and viral gargles for culture were taken. no athlete widi symptoms had a positive bacterial or viral c u l t u r e . the incidence bn kn n st ur r s f p f p fp f p f p d ay -2 to -1 day 0 to 3 day 4 to 9 to 6 i t t t t t s r 17 6 15 11 3 15 8 19 9+ 17 23 23 21 ' 12 14 22 15 21 17 21 17* 28 33 40 27 inere was a ciecreuweu uiciu*,au ̂ \./»j — ©---r(f=1.7%; p=40%: *:p<0.05) in the period day 0-3 after die race, widi a ’ tendency for the nasal symptoms to be lower (f=9%; p=23%:+:p=0.08) in die same period. in summary' post-race urts are not o f infective origin (viral or bacterial) and tiieir incidence can be reduced by a topical anti-inflammatory' agent. hence post­ race urts are likely the result o f an inflammatoiy and not an infective process. supported by servier laboratories sa (ply) ltd. 37 the effectiveness of a mental skills training programme for eastern province academy cricketers h kotras*, l slogrove* *, g robertson* and r stretch * department o f psy chology, university o f port elizabedi, soutii africa * ‘ department of human movement studies, university o f port elizabeth, south africa ** ‘ sport bureau, university o f p o r t elizabeth, soudi africa a major doctrine of sport psychology' is that sport performance is strongly determined bv mental skills. this study evaluated die effectiveness o f a mental skills training programme on the sell reported ‘knowledge of’, ‘importance placed on’ and ‘use ol six mental skills: goal-setting, concentration and attention, arousal and anxiety control, visualization and imagery', confidence, and pre-, duringand post-game activities, i.e., ideal performance state (ips), in a sample of male cricket academy players (11 = 14). selected non-academy players formed a comparison group (n 12). the academy players participated in a six-week mental skills training programme, which involved one ol die six mental skills each week. during each session the particular skill was defined and explained, as w'ere the principles and implementation that applies to that specific mental skill, followed by a practical exercise, where the players were guided tlirough die application of the skill. the players also completed assessments belore and after die programme. the comparison group members did not participate in die programme, but also completed assessments on two separate occasions. overall, the results suggest that the programme was instrumental in changing the ‘knowledge ol ratings most consistentiy across die mental skills, but was less consistent in changing die cricketers’ ‘importance placed on’ and ‘use o f’ ratings. knowing more about: the mental skills and even acknowledging dieir importance in cricket, may not necessary be sufficient in order to lead to enhancement in performance. therefore, cricketers need to be encouraged to practice using and improving dieir mental skills consistentiy and regularly. it may' prove beneficial to integrate die mental skills witii the physical and technical practice, in order to increase the ‘use o f mental skills in cricket perfoimance. the comparison group did not show any significant increase in any' o f die ratings for any' ol the mental skills, wliicli suggests that it was die programme that was instrumental in changing certain ratings. 38 the prevalence of anabolic steroid use in adolescents in south africa mi lambert, m schwellnus, s tidestad. university o f cape town medical school twenty-six schools were randomly selected 1 rom all the schools in 2 geographical regions (a and b). a questionnaire was administered to 2912 adolescents (17-19 years) from these schools to determine the prevalence ol anabolic steroid (as) use and to test their knowledge on as (assessed by a score obtained in response to 8 questions on as). complete data were obtained from 2836 (97.4%) adolescents in the 2 regions (a, n=1361; b, 11=1475). the prevalence o f as use in all the adolescents was 1.4%. the prevalence o f use was higher in region b (2.2%) compared to region a (0.6%) (p<0.005) and in boys (2.8%) compared to girls (0.07%)(p<0.001). when the group was subdivided, d ie highest prevalence o f as use occurred in bovs who competed in d ie first team (3.8%). the score (maximum o f 8) obtained by all sports participants in the knowledge lest (mean ± sd) was low (2.7 ± 1.6). the score was higher in bovs (2.9 + 1.6) than gills (2.3 ± 1.5) (p<0.0o) and sports participants (2.7 ± 1.6) compared to non-participants (2.2 ± 1.6) (p<0.01). in conclusion, this study highlights the problem o f as use in schoolboy's, show's regional differences in as use and a poor knowledge o f as in all the groups. 39 isokinetic strength training of the quadriceps femoris by means of electrical stimulation it , lategan l, loots j m, lourens a, van wyk gj, cilliers pj. biokinetics department, 1 military hospital soudi african medical sendees, pretoria, south africa the primary aim o f the study was to investigate the strengdiening o f die quadriceps femoris muscle group by means o f an isokinetic nmes training programme. 21 subjects, wdtii an average age ol 22.55 y'ears, participated in the study'. a cvbex 340 dynamometer w'as used to measure extension torque at o'.s'1 (60" knee flexion), 60, 180 and 240 .s'1 before and after the nmes training period consisting o f 10 sessions. the subjects were divided into groups: group a (who received isokinetic nmes training) and group c (who served as a control group). in addition, each individual had a designated “ treatment” and “ control” leg; the “ control” leg served as an extra control for determining the effect o f the isokinetic nmes training programme. independent and dependent t tests revealed that 10 sessions o f isokinetic nmes training o f die quadriceps femoris, resulted in statistically significant knee extension torque improvements in group a (for die treatment leg), ato-.s'1 (18.2%), 6 0 \ s’ (20.7%), 180\s' (17.4%), and 240 . s 1 (13.2%), respectively. however, group as control leg also showed statistically significant improvements o f 2.6 and 2.0% at 0 and 60".s\ respectively. additionally, group c s “ treatment” leg showed a significant (p<0.05) improvement in the post-treatment condition o f 6.2%, even though it received 110 nmes treatment. i11 the present study, a safe metiiod ol isokinetic nmes was developed which proved to be viable as a strength training modality for the quadriceps femoris muscle group. the isokinetic nmes training programme at 60\sj resulted in significant improvements in both isometric and isokinetic knee extension torque (p<0.05). 14 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 40 the energy cost of running in field hockey is greater when dribbling a ball b lawther and r carter, department o f physiology, centre for the study o f exercise, nutrition and muscle science, university o f the witwatersrand, medical school, johannesburg, south africa the physiological demands o f field hockey, which employs a unique posture while playing die ball, have mainly been inferred from studying athletes running in the upright posture. in this study, resting pulmonary function was assessed in both die upright and the semi-crouched dribbling posture in eleven male and ten female elite field hockey players. in addition, the players completed a 4 minute run 011 the treadmill at 10,12 and 14 km/hr for the men, and 8, 10 and 12 km/hr ibr the women, whilst both dribbling a 1 >all at the end of a hockey stick and during normal running. the metabolic and ventilatory responses to normal running and to dribbling a hockey ball in the semi-crouched position were evaluated in order to establish the additional physiological strain imposed by this compromised posture. the semi-crouched posture significantiy reduced resting pulmonary' function in both die men and the women (ivc 6.0 ±0 1 .2 vs 6.3 ± 1.21 hi males, and 4.1 ± 0.6 to 4.2 ± 0.6 in females; pef 11.1 ± 2.2 vs 11.8 ± 2 .7 1/s in males, and 8.7 ± 1.7 vs 9.1 + 1.6 1/s in females; p<0.05). dribbling increased energy expenditure above levels observed in normal running, for bodi the men and women at each speed (e.g. 52.2 ± 1.9 to 47.6 ± 2.3 1111. kg .n 1 i 11 in males, and 43.9 ± 2.0 vs 39.8 ± 2.3 ml.kg'.min1 in females at die high speed; p<0.001). heart rate was significandy higher while dribbling at each speed (e.g. 190 ± 6 vs 177 ± 7 beats/min in males, and 189 ± 11 to 178 ± 12 beats/min in females, at the high speed; p<0.001). minute ventilation was significantly higher while dribbling relative to orthodox running at each speed (e.g. 150 ± 25 vs 107 ± 15 1/min in males, and 109 ± 14 vs 82 ± 13 1/niin in females, at die high speed; p<0.001). tliis studv has shown that die compromise in pulmonary function detected in the dribbling posture at rest does not impair the physiological performance of hockey players executing dribbling skills on the treadmill. furthermore, running in the dribbling posture is far more physiologically cosdy dian is orthodox running. the additional strain diat the players experience hi diis peculiar posture must be incorporated in predictions of the energy cost of competitive match-play hockey. 41 mood, and performance of cricketers during an international tour pw macfarlane, university o f cape town, cape town, south africa. objectives: an attempt was made to determine whedier die mood state o f cricketers and the team as a whole could contribute to the extremely variable performance which was noted on previous occasions. methods: a modified questionnaire based 011 die profile o f mood states (poms) was administered by interview wadi each player individually 011 most mornings o f a six-week cricket tour. categories assessed were anxiety, confusion, depression, fatigue, vigour, relaxation, soreness, homesickness, boredom and frustration. results: anxiety scores showed short-term trends and were match-related. higher scores were associated widi better performance. confusion scores appeared to reflect die state o f leadership and success on tour, radier dian predict performance. depression scores were also more a result of events dian a predictor. fatigue was also related to match history. vigour did not mirror fatigue, but was low 011 rest days. relaxation scores were higher during rest periods, but also at the end o f one match when performance was lower. soreness scores did not increase during the tour, but individual variation was evident, d u e ,usually to injury. flomesick scores showed a rising trend, exacerbated 011 the rest days. boredom was lowest at the beginning and highest on rest'days. some individual frustration scores were very' high at certain times, and the team score was high during a period o f poor performance and prior to another period of |m>or performance. conclusions: teams touring abroad cac.e stresses diat are different from what diey and their management are used to at home. this study highlights some o f the general problems such as rest days and motivation which can be taken into account when planning tours in general. certain scores o f mood relate more to die result o f events, and need to be taken into account in managing team morale and strategy on a particular tour. other scores may' predict performance and give early warning o f a dip in form. 42 community based cardiac rehabilitation programmes a pilot project. n mars m, modiilal b* and stubbs j*. south african association of cardiovascular rehabilitation and heart foundation of southern africa*. in die south african indian population over 45 years o f age approximately 50% o f deaths “ from all causes” are due to diseases o f the circulatory system. i11 a large random survey of durban s hidian population, 48% of people over die age o f 15 years were found to have ecg changes. coronary heart disease accounts for 24% o f all deaths in the medical wards o f one of durban’s major hospitals. with increasing intervention surgery and angioplasty' there are a large number of patients who are candidates for cardiac rehabilitation programmes. a review of the rehabilitation programmes hi the durban functional region revealed that diere are about 35 indians attending. analysis of the reasons for the low attendance, revealed die following factors: lack of knowledge o f the medical practitioners o f the benefits o f rehabilitation and o f the sendees available, piaetidoners fear o f “ losing’ the patient, family'pressure 011 the patient to not exercise as it is considered dangerous, inappropriate siting and timing of rehabilitation programmes, and the fear o f losing disability grants if rehabilitated. with this in mind, discussions were initiated with the local community leaders in phoenix. after initial scepticism, a partnership was entered whereby die community would provide facilities, and volunteers to run a tertiary rehabilitation programme. the local doctor’s guild was invited to participate, and although supportive of the idea, tiiey did not offer tiieir time. the volunteers underwent training in cpr, exercise prescription and monitoring, and programme management. general community interest was raised by phone in programmes 011 the community radio, radio lotus, and equipment was donated bv the public. the service is free, and tiiere is no budget. all incidental costs such as printing etc have been borne by donation from the local community. the programme has been running for 3 months and is growing. there are requests from other indian communities to start similar projects in their areas, and project committees are being established. 43 infra-red laser: an in vitro dosimetry study mars s, cliulurgoon a and mars m. dept, o f physiology', university'of natal medical school, durban, soutii africa. low intensity' laser tiierapy is a popular treatment modality used to enhance wotuid healing. a commonly used commercially available low intensity infra-red laser is the superluminous diode based gallium aluminium arsenide laser, 830nm. there is however little scientific evidence to support bodi its efficacy and optimal dosage. the literature on die use o f laser is confounded by a lack o f standardisation o f terminology witii respect to dosage which has been expressed hi terms of power, power density or energy' density'. there are few dosimetry' studies using infra-red laser directly on fibroblasts. the aim o f this pilot study was to investigate the effect o f different doses o f infra-red laser 011 fibroblast activity in cell culture. human fibroblasts were cultured, and confluent fibroblast cells were trypsiuized and resuspended in culture medium to give a measured cel1 count o f 11 x 10* cells/ml. 100ml o f cell suspension and 200inl o f culture medium were titrated into each well of a 96 well microtiter plate. the plate was then incubated 37'c until confluent. ten o f die twelve eight well channels were irradiated on three consecutive days at energy densities o f 0.2, 0.4, 0.6, 0,8, 1, .1.5, 2.3, 3, 4 and 5 j.cm 3. each well was irradiated individually. the two end channels of eight wells each were not irradiated and served as controls. on the day after die last treatment, cell viability was measured using the mtt assay, which is an indicator of mitochondrial enzyme activity'. the optical density o f each well was measured spectrophotometrically at a wavelengdi o f 595 mil witii a reference wavelength o f 630nm. analysis o f variance showed a significant difference between fibroblast activity at different doses (p=0.004). post hoc testing revealed significant differences between die controls and diose cells treated widi the low dose 0.4 j.cm and die highest dose 5 j.cm 3. previous studies have not used doses as low as 0.4 j.cmand increased activity at tiiis dose is a novel finding. the increased activity' at 5 j .c m 3 is hi keeping with other dosimetry studies. the information gained in this study on dose efficacy w ill be used to evaluate a new in vitro model o f wound healing. sports medicine march 1997 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 44 the risk of human immunodeficiency virus (i i i v ) transmission in boxing kop m a t s e k e , m p s c h w e l l n u s , s p o i l s medicine, d e p a r t m e n t o f physiology, u n iv e r s it y o l c a p e town hiv disease is a fatal disease that can be transmitted through contact with blood or blood products. sports participants that engage in contact sports such as boxing, are therefore at risk to acquire the condition. in boxing, the precise risk o f transmis­ sion has not been documented. the risk o f transmission o f fhv in boxing is dependent upon the following four factors: i) die seroprevalence o f hiv infection in boxers, ii) the risk ol an open bleeding wound in a boxing bout, iii) the risk o f contact between the boxers, and iv) the risk o f transmission of.the virus when bleeding wounds make contact. the aim ol this study was to determine the risk o f transmission o f hiv during a boxing bout. assuming that the risk o f contact between two boxers is 100%, and that the risk o f transmitting the vims when open bleeding wounds make contact is 5% (similar to that o f a needlcstick injury), two studies were designed to firstly determine the sero­ prevalence o f hiv in professional boxers in south africa, and secondly to calculate the incidence o f open bleeding wounds in professional bouts in south africa. the nature o f the bleeding wounds was also studied, as well as current precautions that boxers and support staff in and around the ring take. in the first study, medical records, in particular the htv status, in the year alter compulsory hiv testing was introduced at routine annual medical examination, were obtained from all the professional boxers in south africa (with approval o f the sa boxing board of control). a total o f 925 boxers were registered, and the hiv pos­ itive prevalence rate was 9%. in the second study, video clips of 30 professional boxing bouts were studied. during each bout, the following data were obtained: the presence o f an open bleed­ ing wound, die type and site o f injury, die amount o f bleeding, contamination bv the blood, and d ie action taken by cornermen. in 14 out o f 30 bouts, an open bleeding wound was sustained by a boxer (46.7%). /ml the injuries were in the face/head (100%), and most injuries were lacerations (54%), followed by contusions (21%), abrasions (6.5%) and otiiers (18.5%). the amount o f bleeding was classified as mostly present but not flowing (46%), followed by fast flowing and dripping off (25%), slow flowing and not dripping (20%), and no bleeding visible (9%). the blood con­ taminated the following: boxing gloves (31%), towels (26%), skin (19%), ring or railing (10%), cornermen (8%), and referee (3%). actions taken by cornermen were attempts to stop bleeding (40%), washing with water (27%), wiping but no attempt to stop bleeding (25%), and no action (8%). the risk o f hiv transmis­ sion in south african boxers during one bout was therefore cal­ culated as follows: seroprevalence (0.09) x the risk of an open bleeding wound (0.467) x the risk ol contact (.1) x risk of viial transmission between wounds (0,05) = 0.0021 (1 in 476 bouts). professional boxing in south africa therefore carries a signifi­ cant risk o f hiv transmission. preventative measures to decrease the risk oi l l iv transmission should include education o f boxers and support staff, reducing the risk ol contamination, and appropriate action of contaminated material. 4 5 imf, effect of low -dosage, long-term c reatin e m onohydrate supplementation on t h e performance of cyclists france m oilcr, wayne v iljocn, pauline nicmvoudt, j a cq u cs rossomv, d epartm ent sport s ciences, technikon pretoria, pretoria, south africa previous studies on creatine m onohydratc concentrated on the effect o f high-dosage, short-term supplementation on athletic perform ance. t his study exam ined th e effect ofloxv-dosage (3 g /d a v ), long-term (12 w eeks) creatine luonohvdrate supplem entation on b lo o d lactate accumulation, pow er output mid fatigue. eleven well-trained m ale cyclists perform ed repeated bou ts o f th e 30-second wingate anaerobic test. finger-sample m easurem ents for b lood lactate w ere taken at rest and alter each o f the three bou ts o f maximal cy clc ergometry. peak power output, average pow er output, total work and pow cr-drop w ere com puted. no significant d ifferences were reported for average power output and total work after th e adm inistration period. creatine supplem entation led to a significant decrease in pow er-drop during all d iree exercise bou ts (pj ̂ = 0,003: p2 0,009: p3 = 0 ,0 2 8 ) and a significant decrease (p = 0,0 0 9 ) in blood lactate accumulation. a significant increase (p = 0,0 9) in mean pow er output w'as recorded during th e last 15 secon d s o f the exercise bouts. we therefore concluded that for well trained cyclists perform ing repeated bouts o f maximal exercise, low dosage loiig-tcm t crcatin c m onoli\diate supplem entation significantly d ccrca se d fatigue and b lo o d lactate accumulation. funding: p pl. (ptv) ltd. 4 6 electromyography and serum electrolytes during recovery from e x e r c is e a s so c iat e d muscle cramping (eamc). j nicol, m p s chw ellnus, t d noakes, m r c /u c t bionergctics o f e xercisc r esearch unit univ. of c ape town, rsa. t h e anil o f this study was to relate baseline integrated surfacc clectrom vograpliic (biem g) activity mid serum electrolyte concentrauons (sec) to clinical recovery in runners with eamc. subjects were runners presenting with acute severe (unable to walk) eamc after a 06 lan race (e, n =11). controls for d ie sec (cl, n = 11) were runners m atched for age, gender and linishing tim e who com pleted the o 6kni race without eamc. controls for the biemg (c2, n = 7) were runners with no eamc after a 35 km run. biemg was recorded i) in the affected muscle (quadriceps (q), gastrocnemius (g )) of the subjects in the e group on adm ission o'o) and after recovery (60 minutes later) (t60) during periods w hen th e runners w ere not experiencing a spontaneous m uscle contraction (biemg) and ii) in the c2 group in the q an d g m uscles attci the 35 km run (to) and 60 m inutes later (t60). emg data w ere expressed as % change in biemg f l o to t60). t he % decrease (mean (sd )) 0 0 vs 'w 0 ) in biemg for the e group (52 (2 5)) was significantly greater (p <0.05) than the c2 group (12 (47)). t he results o f blood sam ples collected for measuring sec (m niol/1) on admission (to) and 60 minutes later f 160) in d ie e and c groups are dcp icted in table 1. table 1 : serum electrolyte concentrations ((m ean (so)) during recovery from eamc na+(minol/l) ka+(nimol/l) ca++(minol/l) mg++(nmiol/l) la : c l group to: e group 1 6 0: c l group 160: e group 142(3) 142(2) 141(3)** 140(3) 4 .7 (0 .4 ) 4 .3 (0 .5 )* 4 .4 (0 .0 5 )* * 4 .2 (0 .4 ) 2 .3(0.1) 2 .3 (0 .1 ) 2.1 (0.3 ) 2 .2(0.1 ) 0 .7(0.1) 0.7(0.1) 0 .7(0.1) 0.8( 0.1 ) * p<0.05, e vs c l group at to: **p < 0 .05, to vs t 60 for c l group til esc' results indicate that i) runners with eamc have greater biemg activity than control runners during the next race period ii) d ecreases in biemg activity are associated with recovery from eamc, iii) there is no relationship between sec and cither recovery from eamc o f biemg and iv) that differences ill serum k+ and n+ between e and c l are not o f clinical significance. supported by the sports m edicine research fund o f the university o f cape town. 4 7 serum electrolyte concentrations and hydration status in runners with exercise associated muscle cramping (eamc) j n icol, m p s ch w e lln u s, t d n oak es, s p orts m e d icin e , m r c /u c t b ion erg ctics o f e xercise r csearcli unit university o f c ape town, rsa. t he aim o f this study was to determ ine w hether acute eamc in distance limners is related to changes in scrum electrolyte concentrations (sec) and hvdration status (fis). a coh ort o f runners (n=44) participating in a 5 6 kni race all w idi a history o f eamc were recruited. body weight was measured and blood sam ples for blood glucose (bg), sec, serum osmolalitv (o sm ), haemoglobin and hacm atociit w ere collcctcd from all the limners 30 mill before the race (tb) and im mediately oil completion o f the race (to). samples for sec and osm were also collcctcd 60 lnin f ! 6 0 ) after the race. t he cohort was divided into a group o f runners (c, n=21) who suffered from eamc during the race, and a group with no eamc (n, 11=23). bodi groups had similar [(m ean (s d )j age (years) [n:42(8), c :37(8)l, pre-race bw (kg) [n :73(8). c :7 8 (ll)l,' and race finishing tim es (m ill) [n:304(36), c:309(41).|. runners with eamc were treated onlv with rest, passive stretching and oral fluids,and all had recovered by 'w0. sec (m m ol/1) b gom nol/l), osm (m osni/1) and hydration status (calculated as % change in bw (% bwc) and % changc in piasnia volume (%pvc) w'cre com pared in the c and n groups using anova g ab le 1). table 1. b lood glucose and scrum electrolytes in th e n and c group at tb, to and t60. bg \ra+ k+ ca++ mg++ osm ta:n 6 .1 ( 1 .1 ) 13 9(2) 4 .4 (0 .4 ) 2 .2(0.1 ) 0.8(0.1 ) 282(4) tb:c 6 .3(3.1) 139(2) 4 .5 (0 .4 ) 2 .2(0.1 ) 0.8(0.1 ) 28 4(5) ta2:n 6 .5(2.0) 14 2(2) 4 .7 (0 .5 ) 2 .3(0.1) 0.7(0.1) 28 4(10 ) ta:c 6 .8( 1 .9) 14 0(3) 4 .9 (0 .6) 2 .3(0.2) 0.7(0.1) 28 0(16 ) t60:n 6.5 (1.0 ) 142(2) 4 .6 (0 .5 ) 2 .2( 0.2) 0.7(0.1) 183(8) t 60:c 6 .3(1.0) 140(2) 4 .7 (0 .5 ) 2 .2( 0.3) 0.8(0.1 ) 28 4(7) t here were no significant differences in the sec, bg, osm and iis between th e c (% bwc: 2.9 (1.3), %pvc: 0.2 (6 .3 )) and the n (%bwc : 3 .6 (1.2), % pvc : 0.7 (8.6)) group. t he results o f this study refute the hypothesis that eamc is associated with changes in sec and hs. supported by the sports m cd icin c research fund o f the university' o f cape town. 16 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 48 psetjdoephedrine is without ergogenic effects during prolonged exercise h gillies, we demian, td noakes*, p smith, a evans, g gabriels. university o f cape town medical school. this study was designed to measure whether a single dose o f 120 mg pseudoephedrine ingested 120 minutes before exercise influences performance during 1 hour o f high intensity exercise. the effects of exercise on urinary excretion o f the drug were also studied. ten healthy male cyclists were tested on two occasions, separated by at least 7 days, using a randomly .assigned, double-blind, placebo controlled, crossover design. exercise performance was tested during a 40 tan trial on laboratory cycle ergometer and skeletal muscle function was measured during isometric contractions. on a third occasion, subjects ingested 120 mg pseudoephedrine but did not exercise (control = c). pseudoephedrine did not influence either time trial performance (58.1 ± 1 .4 vs 58.7 ± 1.0 mill; mean ± sem: drug (d) vs placebo (p) or isometric muscle function. urinary pseudoephedrine concentrations (114.3 ± 27,2 vs 35.4 ± 13.1 ug/ml; p < 0.5) were significantly increased one hour after exercise (d vs c). peak plasma pseudoephedrine concentrations (p < 0.05) but not time taken to reach peak plasma concentrations nor the area under the plasma pseudoephedrine concentration vs time curve was significantly increased in the total group with exercise (d vs c). in three subjects, plasma pseudoephedrine concentrations were not influenced by exercise. only these subjects showed increased urinary pseudoephedrine excretion during exercise. we conclude that, a single therapeutic dose o f pseudoephedrine did not have a measurable ergogenic effect during high intensity exercise o f 1 hour duration. but plasma drug concentrations and urinary excretion were altered by exercise. these findings have practical relevance to doping control ivgu la i ions in international sporting competitions. 50 rate of pi asm a lactate clearance during passive recovery from high intensity e x p o s e tanya oosthuyse and roderick carter, department o f physiology, university o f the witwatersrand johannesburg, south africa. an athlete’s ability to repeatedly perform at high intensities during intermittent exercise could b e related to accelerated plasma lactate removal during the recovery phase. we determined the rate o f plasma lactate disappearance during passive recovery after an incremental exercise test to exhaustion on a bicycle ergometer in live trained and five untrained male subjects. venous blood samples were taken during exercise and recover)' at set intervals for the analysis o f plasma lactate concentration. the endurance fitness of the subjects was characterised from die work load at the lactate turn point (lip) and classified as maximum turn point power out (mtp) in wkff '. the mean mtp o f the trained group was 3.92 ± 1.8 w k g1 and 2 .1 ± 0.51 \y. kg for the untrained subjects. from the exponential curve of percentage ol peak plasma lactatc vs time during passive recovery we determined die rate o f lactate clearance at 5min, lomin and at die equivalent lactate concentration to diat found at the lte we also determined the time taken to clear 30% and 50% o f peak lactate concentrations, and die time to return to ltp concentration in recover)'. using spearman rank correlation, no significant relationships were demonstrated between the recovery parameters measured from die curve and endurance fitness (rs, spanning an interval of -0.042 to -0.31). our study shows that, after exercise at equivalent relative maximal work loads, trained subjects do not have an improved ability to remove plasma lactate during passive recovery. we propose that this physiological response may be a consequence o f the decrease in blood and muscle pi i and die rise in circulating catecholamine concentration during high intensity' exercise. also, d ie low muscular energy demand during passive recover)' decreases to drive to remove lactate for use as a fuel substrate. many studies have shown that training enhances the rate o f lactate removal. however, we found diat training confers no adv antage to the rate of lactate removal while recovering passively from exhaustive 49 institutional review boards and scientific progress steve olivier. university o f ziduland, kwadlangezwa, soudi africa. research into the limits o f human performance has become a growth industry, and critical to investigators is a readily available supply o f subjects. however, history attests that free scientific inquiry and social stability have often been at odds. particularly when research (and the freedom to conduct it) impinges on the perceived rights o f individuals or groups, a sense o f alarm grows even iu societies that have traditionally given free rein to such activities. as a result, there have been, and continue to be, numerous demands for the regulation o f research with injurious or invasive potential. growing acceptance of ethical principles such as autonomy, as well as public reaction to past abuses, has led to die establishment o f institutional review boards (irbs). this paper examines the structure, function, and effectiveness o f irbs, and specifically focuses on the notion that the institutionalisation o f these committees has created a growing bureaucracy that retards scientific progress bv reducing creative nonconformity. the paper evaluates the argument that not only is ethical review endangering valuable research oil human beings, but that it is also endangering the very ethic that is needed to govern such research. future strategies and possible solutions are explored, and the paper concludes that die imperfections o f the concept shoidd not lead to the ethical review process being discarded. 51 the epidemiology of injuries in south african senior school soccer players j ramatliesele, mp scliwelhius, sports medicine, department o f physiology, university o f cape town tlie auii of this study was to document the epidemiology of injuries sustained by soutii african senior school soccer players. subjects for the study were selected from all die senior schools (n=20) in tembisa (gauteng, soutii africa). a cohort o f 227 senior school soccer players, representing all die players in die tembisa schools, was followed over one playing season. all prac­ tice and match hours were recorded and specific injury report forms w'ere completed by all the coaches. all injured plavers were then referred to the principle investigator (jr) for detailed examination to document injuries. factors such as pre-season training, warm-up, stretching, playing surface, environmental factors, and the use o f protective equipment was also recorded, hi this study, 63% of all the players sustained an injur)' during die season (seasonal incidence). the overall incidence of injuries was 9.04/1000 hours o f play. the incidence of injuries in match­ es was. 274 times higher than hi practices. more dian half (57%) o f the injuries were classified as moderate severity. the highest incidence of injury per player position was in goalkeepers (13.7/1000 horn’s play). the low'er extremity accounted for most injuries (88.8%), widi the ankle (42.4%) and the loiee (27.1%) mostly affected. the type o f injur)' was mostly a ligamentous sprain (68%), followed by musculotendinous strains (15.8%). tliere were only two joint dislocations, and no fractures. all die participants in this study played on grav'd pitches and on no occasion a first aid kit was available. the majority of players were not aware o f appropriate stretching, warm-up, and strap­ ping techniques that can be used to prevent injuries. none o f die players engaged in any form o f pre-season training. in only two of the schools (10%) the soccer coaches had any formal training with coaching certification. although the injury rate in senior school soccer players in tiiis study is only slightiy higher dian that reported by others, it is clear that scientifically based mea­ sures o f in jury prevention (pre-season training, warm-up, stretch­ ing, and stra|>ping) need to be implemented in these schools. in addition, proper sports and first-aid facilities should be provid­ ed , and coaches should receive formal training. sports medicine march 1997 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 52 the effect of endurance training on hypothalamic 5-hydroxytryptamine (5-ht) receptor function k scheepers, m lambert, j du buisson, t noakes and w dermaii, university o f cape town and sports science institute o f south africa. previous studies indicate that the serotonergic nervous system plays an inhibitory role in the central control o f fatigue during prolonged exercise. researchers have also demonstrated a down-regulation o f 5-ht receptor function in elite endurance trained subjects, compared to sedentary controls. this study examines the effect o f endurance exercise training on 5-ht receptor function in 7 recreational athletes (t) who underwent training and improved their 5 km time, and 6 sedentary' controls (c). prior to, and after a 5 month exercise training programme, subjects underwent a 12 hour fast and baseline blood sample w as drawn for determination o f serum prolactin concentration [pr]. subjects then ingested 60mg o f buspirone, a partial 5-ht la receptor agonist. serial blood samples for [pr] were drawn every' 30 minutes for a period o f 4 hours. the [pr] response to buspirone challenge was determined, thus providing an indication ol' 5-ht receptor sensitivity. average auc [pr] concentration before training were similar in t compared to c (915±316 vs 700±258 iu.min/l). after training [pr] in the t group tended to increase to 1141.6±316 iu.min/l (p<0.1) hi contrast to [pr] in c w'hich remained the same (748+117 lu.min/l). peak [pr] concentration w'as higher in t than in c both before (742.2±409 iu.m in/l vs 535.8±289.9 iu.min/l) and after (842.6±439 iu.m in/l vs 504.5±87.4 iu/1) the intervention. conclusion: this study shows i) there is a trend tow'ards an up-regulation o f hypothalamic 5-ht receptor function after training in recreational endtuance athletes; ii) differences seem to occur in the response o f the serotonergic svstem to endurance training in elite, com pared with recreational athletes. 53 abnormal patterns of knee medio-lateral deviation (mld) are associated with patellofemoral pain (pfp) in cyclists j milligan, m schw'ellnus facsm, td noakes facsm. sports medicine, uct the aetiology o f pfp in cyclists is not w'ell understood. the aim o f this study was to document the relationship betw'een pfp and abnormal patterns o f knee movement during cy cling. eighteen cyclists w'ere recruited and eight (e,n=8) fulfilled the diagnostic criteria for pfp in 12 knees (bilateral pain in 4 subjects) (kp,n=12). tw elve controls (c,n=12) w'ere pain free in 24 knees (kc,n=24). subjects in the e and c groups had similar age (vears) [mean (sd)j [e,27(9)); c, 29(9)], height (cm) [e, 179(8); c,184(5)], and body weight (kg) ie,75(9); c,80(5)]. using high speed two-dimensional video analysis, reflective markers placed on the knees o f all the subjects w'ere filmed during cycling (>20 revs). subjects used tlieir own cycling shoes and bicycles w'hich w'ere mounted on rollers. the movement o f the reflective markers was plotted on a screen, digitised and measured. the patterns oi knee movement [normal linear (nl), deviated oval (do), deviated figure o f eight (df), deviated combined (do+df)] and the average medio-lateral deviation (mld) o f the knees was recorded. prior to the study, the repeatability o f this technique w'as established (r=0.93). the frequency o f patterns o f knee deviation in the kp and kc groups is depicted in table 1. table 1: frequency o f patterns o f deviation o f tlie k nee in the kp and d ie kc knees nl do+df do df kp (n=12) 0 /1 2 * 1 2 /1 2 * 8 /1 2 * 4 /1 2 kc (n=24) 1 7 /2 4 7 /2 4 6 /2 4 1 /2 4 *: significantly d ifferent between kp and kc (p ,0.0 0 1 ) the mt p [mean (sd)1 (mm) o f the kp [14(5)] was greater than in the kc group [8(3)] (p<0.001). this study show's that pfp in cyclists is associated with non-linear patterns o f knee movement and excessive mld o f the knee. correcting uon linear patterns and decreasing the mld may be important in the management o f pfp in cyclists. supported by tlie sports medicine research fimd o f the university' o f cape tow'n. 54 correcting lower limb kinematics decreases patellofemoral pain (pfp) in cyclists e van zyl, m schw'ellnus facsm, td noakes facsm. university' o f cape town. in cyclists with pi'i! abnormal oval (o) or figure-of-8 (f) patterns of knee movement during d ie downstroke in cycling resulting in excessive medio-lateral deviation (mld), have previously been documented using 2d video analysis. using 5 different methods [5mm medial forefoot w'edge (mw), 5mm lateral forefoot w'edge (lw), 5' internal foot rotation (ir), 5" external foot rotation (er), a raised saddle (rs=110% previous height)], correction of abnormal knee movement (mld> 10mm) w'as tested in 15 cy'clists (32 ± 9 y'ears, mean ± sd) (0=12; f=9). a significant reduction in mld (mm; mean ± sd) wras achieved-by' mw (18 ± 8; p<0.0001) and rs (19 ± 9; p<0.0005) but not by lw, ir, or er. once corrected to tlie most linear pattern using the niost effective method o f correction (lowest mld), all 15 cyclists performed a 30m in (3x10niin) cycling test at predetermined w'ork loads (125w, 180w, 200w) after 3 training periods (t1 = 4 w'eeks training with no correction, t2 = 4 w'eeks training w'ith correction, t3= 4 w'eeks training with correction removed). during each test, pain experienced w'as plotted every minute using a visual analogue scale (vas: 0-10; 0 = no pain, 10= unbearable pain). total pain (tp) (pain units) was calculated as the area under the pain vs time graph. tp (mean ± sd) was decreased after the t2 period (19 ± 23), compared to after tlie t1 (42±40) or the t3 (34 ± 42) period (p<0.0004). cyclists also recorded daily pain (vas: 0-10) during training in each 4 w'eek period (t l, t2, and t3). pain/training ride/day (ppd) was calculated for tt, t2, and t3. ppd (mean ± sd) w'as decreased during t2 (1.4 ± 1.2), compared to t l (3.0 ± 1.7) or t3 (2.2 ± 1.5)(p<0.002). in conclusion, i) cyclists with pfp exhibiting excessive mld o f the downstroke can be corrected to a more linear pattern using minor biomechanical modification, and ii) once corrected, pfp during cycling decreases. supported by the sports medicine research fund o f the university o f cape tow'n. 55 post match ecg changes in veteran squash players is it a problem? sibbald h, weston a, naidoo dp, and mars m. depts. o f physiology', and medicine, university' o f natal medical school, durban, soutii africa. veteran’s squash has a large following in south africa. participation in high intensity' sports by competitors over tlie age o f 45 years is considered potentially hazardous, and squash is considered to have a relatively high risk o f associated sudden death during or following play'. in a study by' northcote, 7/21 subjects in a group aged 23 43 y'ears, showed significant electrocardiograph (ecg) changes in the hotu after play. the aim o f this pilot study was to determine the frequency o f post match ecg changes in squash players over the age o f 45 years, who participate in league squash. eighteen volunteers were studied. their ages ranged from 45 to 54 (mean 49 ± 3 yrs). resting ecg’s were obtained before play'. during match play, heart rate was recorded using heart rate monitors. on completion o f the match, subjects w'ere immediately fitted w'ith holter monitors and their ecg’s recorded for the hour after play. the data .from the holter monitors were downloaded by an independent technician and read by a cardiologist, blinded to the study. the matches were play ed at an average o f 87% o f predicted maximum heart rate (p1mhr), w'ith an average o f 44 % o f match play occurring at above 90 % o f pmhr. tlie mean maximal heart rate achieved dtuing play' w'as 169 ± 14 b/m in (99% o f pmhr). anova show'ed no difference between intensity o f games, there w'as how'ever a significant difference betw'een the hardest and the easiest game. (p< 0.0001) no abnormalities w'ere noted in the resting or post match ecg’s. this study confirms that veteran squash play'ers play' at a high intensity. tlie failure to demonstrate post game ecg changes may be due to the sample size, but it may' also suggest that those who continue to participate actively' in veteran’s squash have selected themselves out as a relatively low' risk group on the basis of having had no warning symptoms o f cardiac problems. further studies are required to compare exercise stress test ecg’s w'ith post match ecg changes. 18 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 56 cardiac performance in veteran squash players and runners during a routine stress ecg, squash and running a st clair gibson, j perold, ga watermeyer, ja hawley, mi lambert, td noakes. exercise science unit, university o f cape town, cape town, sa. the aim o f the study was to assess the relationship between cardiovascular performance in a routine stress ecg and during field testing in veteran squash players and runners. ten veteran league squash players (lsp), 10 social squash players (ssp), 10 league runners (lr), 10 social runners (sr) and 10 sedentary individuals (sed) were recruited for the study. ah subjects filled in a lifestyle questionnaire, underwent a complete medical examination and performed a routine stress electrocardiogram (ecg). the sport playing groups subsequently underwent heart rate monitoring during their specific sport activity on two separate occasions. there were no differences in age, stature and medical history between the groups. the sed group had a significantly higher percentage body fat (p < 0.05), mass (p < 0.01) and resting heart rate (p < 0.01) than the lr group. although there were no significant differences between the mean heart rate attained during the field test and the maximal heart rate attained during the ecg test, a highly significant difference occurred between the maximal heart rate attained in the field and maximal heart rate attained during the ecg test for all groups (p <0.01). the maximal heart rate during routine exercise is significantly higher than that attained dtuing a routine stress-ecg test. this finding was not sport specific or related to level o f competitiveness o f sports participants. caution thus should be exercised when advising patients to exercise freely on the basis o f a routine stress-ecg. 57 the energy expenditure of a non-contact boxing training session compared to submaxtmal treadmill running a st clair gibson, b bellinger, a oelofse, r oelofse, mi lambert. uct exercise science unit, university o f cape town, cape town, sa the aim o f this study was to determine the energy expenditure o f a one hour non-contact boxing training session and to compare these results to the energy expenditure o f a more conventional recreational activity such as running. eight healthy males, accustomed to non-contact boxing training, were recruited for the study. subjects underwent 3 tests; (i) a boxing training session in (lie laboratory during which energy' expenditure was m easured continuously using indirect calorimetry' (boxl), (ii) a boxing training session in a boxing studio during which heart rate was measured continuously' (boxs), and (iii) an incremental running test on the treadmill during which energy' expenditure was measured continuously. the energy expenditure during 60 minutes o f boxl ranged between 2519 and 3079 k j (2821 ±190 k j). seven o f the 8 subjects had higher heart rates during boxl compared to boxs, suggesting that the subjects exercised at a slightly' higher intensity during boxl, possibly because o f the “ one oil one” supervision. the average running speed on the treadmill at which the subjects had a similar energy expenditure was 9.2±0.8km .hr1. 58 the heart rate response of crickft umptwpq to on-field events ^ r,stretch*, j tyler** and s bassett*** * sport bureau, university' o f port elizabeth ** department o f statistics, university' o f fort hare *** department o f human movement studies, university' o f fort hare this study assessed die differences between the heart rate responses, recorded every 15 seconds, o f 6 provincial and 4 international umpires to on-field events during limited-overs cricket matches. specific on-field events including appeals, the umpires resulting decisions and any' other tasks the umpire had to make such as calling a no-ball or a wide, w'ere recorded. the results show'ed that the international umpires (iu) rated the on­ field decisions as less stressliil than the provincial umpires (fu), who showed a far greater variance with regard to lbw, catch, run-out and wide-balf decisions. tachycardia occurred before the match resulting in a high mean (±sd) heart rate (iu 102.0 ± 13.9 beats m i n p u 97.5 ± 11.1 beats m in1), corresponding to approximately 60% o f estimated maximal heart rate. similar mean heart rates for the first innings (iu. -101.5 ±12.5 beats min pu 99.7 ± 13.5 beats m in') and second innings (iu 99.5 ± 8.9 beats m in 1; pu 100.2 ± 10.1 beats m in') w'ere found. differences (d = -0.7 beats m in') betw'een the heart rate o f iu and pu prior to the match (102.0 ± 13.9 beats m in') and the first session (101.3 ±12.0 beats m in1) o f the first innings w'as significantly less (p < 0.05) than the corresponding difference (d = 7.5 beats m ill1) prior to (95.3 ± 10.7 beats min'1) and during the first session (102.8 ± 9.9 beats min'1) o f the second innings. a significant difference (iu-d = 0.0 beats m ill‘; pu d = -6.0 beats m in1; p < 0.05) occurred between the difference between the mean heart rate for the second (iu 97.0 ± 6-7 beats m i n p u 101.2 ± 9.2 beats min ‘) and the third (iu 97.0 ± 5.2 beats min ■; pu 95.2 ± 11.4 beats min'1) sessions o f the second innings, illustrating greater variation for the inexperienced umpires. the pu show'ed greater, although non-significant, variations to an appeal at the time o f the decision, 15s post decision and 30s post decision, with both tachycardia and bradycardia occurring. heart rate data o f an iu during an international hat-trick (three wickets in three balls) show'ed anticipatory tachycardia. it can be concluded that the heart rate response o f the umpires to on-field events indicate that they are under tremendous psychological pressure, with international umpires, although umpiring at a higher level, better able to handle these pressures. 59 an analysis of the hr-vo,, relationship during free-range exercise in the laboratory. e terblanche and ja wessels. department o f medical physiology, university o f stellenbosch, po box 19063, tygerberg, cape town. laboratory estimates of heart rate are often used bv coaches and athletes to identify' field training intensities. this approach, how'ever, assumes that the relationship between heart rate (hr) and oxygen consumption (v02) remains constant under all conditions. it has been shown that representation o f fiefd performances during laboratory testing cannot necessarily depend on this assumption, simply because the mode o f exercise appear to be the same.1 it was the aim o f this study to determine the hr v0o relationship for different modes o f free-range cycling in the laboratory. fifteen cyclists (fit and unfit) between the ages of 18 and 26 volunteered to participate in the study. they' performed a 30 km time trial (tt) on a computer controlled cycle ergometer, using a laboratory' simulation o f field cycling. during this test the cyclist could select and change (lie gear ratio and pedal frequency at will. both hr and v0o w'ere monitored continuously' and diese results w'ere compared to the cyclist’s physiological responses during a progressive, incremental exercise test to exhaustion. although there was a linear relationship betw'een hr and v02 during simulated field cycling and the maximal exercise test, there were significant differences in the intercepts (102 ± sem 6.6 b/m in vs 66 ± sem 3.7 b/min; p = 0.009) and slopes (0.02 ± sem 0.002 re 0.03 ± sem 0.003; p = 0.01) o f die 30 km tt and progressive, incremental exercise tests. these results indicate that standard laboratory exercise tests underestimate the “ normal w'orking limits” o f cyclists during free-range cycling and that extrapolation of laboratory results to field exercise should be done with caution. (1 ) kenny gp et al. a comparative analysis o f physiological resjx>nses at submaximal workloads during different laboratory simulations o f field cycling. eur j appl phys 1995; 71: 409 415. sports medicine march 1997 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 60 effect of prophylactic dose of flurbiprofen on muscle damage and cardiovascular variables during submaximal exercise. terblanche s, noakes td and lambert ml bioenergetics o f exercise research unit, sport science institute o f south africa, cape town, south africa. aim: to determine the effect of an prophylactic dose of flurbiprofen on muscfe damage, soreness and cardiovascular variables during submaximal exercise in recreational athletes. methods: 19 male recreational athletes (age 28 ± 12 years; x ± sd) were recruited for the study. subjects underwent a v0onlax and peak treadmill running speed (ptrs) test three days before the first submaximal test and 72 hours after tlie induction o f delayed onset o f muscle soreness (doms). twelve hours before the submaximal test and every 12 hours thereafter until the end o f the experiment, the subjects placed patches with 40mg o f flurbiprofen (transact; n = 10), or identical patches without drug (placebo; n = 9), on tlieir quadriceps muscles. subjects ran for 15 minutes at 75% ptrs during which cardiovascular variables were measured and blood was collected. thereafter doms was induced by a series o f eccentric muscle contractions. the submaximal test was repeated 24 and 48 hours after doms was induced. results: pain, assessed subjectively, increased similarly in both groups. pain, measured with a pressure probe, was significantly higher in placebo than transact at 24 and 48 hours after the induction of doms (p < 0.03). blood ck activity increased similarly in both groups (p < 0.05). wcc (p < 0.03), neutrophil % (p<0.04) and lymphocyte % (p < 0.03) were significantly increased in tlie placebo group, 2.5 hours after doms. blood lactate concentration was significantly higher in placebo after the 15 minutes submaximal test compared to transact, even before the induction o f doms (p < 0.05). serum cortisol concentration was not different throughout the experiment. tlie relative perceived exertion (rpe) during tlie submaximal test was higher in the placebo group after 48 hours (2.0 ± 1.8 vs 1.0 ± 1.3; p < 0.05). the average heart rate increased significantly more in the placebo group during the submaximal test compared to the transact group (5.1 ± .7 vs 0.3 ± 2.3 beats.m in1; p < 0.(in). neither v02„„„ nor ptrs differed between groups through the experiment. conclusions: these data show that prophylactic treatment with transact before tlie induction o f muscle damage reduces the severity o f doms. we want to thank boots pharmaceuticals for their financial assistance. 61 morphology and intrinsic injury risk in schoolboy rugby hj van heerden, department human movement science, university o f zululand, rsa thus far epidem iological research has exposed typical extrinsic injury risks o f rugby. however, well controlled studies on potential risks that are intrinsic to the individual have been absent. this study thus focussed on morphology as an intrinsic aetiological risk factor in schoolboy rugliv injuries. a well defined population o f high school rugby players (n=105) aged 13-17 years were monitored utilizing a prospective injury surveillance design with an injur)' being defined as either requiring medical referral or causing a loss ol at least seven days from participation. risk factors were subsequently identified by anova, contrasting preparticipation morphological profiles o f in jured players with those o f tlie non­ injured controls. results for injured vs lion-injured players indicated a significantly (p<0,05) greater stature (176,8 ± 8,6 vs 172,0 ± 8,7 cm); body mass (69,7 ± 11,3 vs 63,9 ± 12,6 kg); lean body mass (60,0 ± 9,7 vs 52,3 ± 9,6 kg); and a lower body fat (13,9 ± 3,1 vs 17,9 ± 6,6%), respectively. individual somatotype component variations in endomorphy (2,4 ± 0,9 vs 2,9 ± 1,5); mesomorphy (4,8 ± 1,0 vs 4,9 ± 1,2); and ectomorphy (3,2 ± 1,0 vs 3,2 ± 1,4) did not differ significantly (p>0,05). iii conclusion the data suggests that morphological superiority among high school rugby players appears to predispose rather than preclude from injury' whilst somatotype is independent from injury' risk. 62 muscular “ fitness” and intrinsic injury risk in schoolboy rugby ej van heerden, department human movement science, university o f zululand, rsa. thus far epidem iological research has exposed typical extrinsic injury risks o f rugby. however, well controlled studies on potentitd risks that are intrinsic to the individual have been absent. this study thus focused on musculoskeletal “ fitness” as an intrinsic aetiological risk factor in schoolboy rugby injuries. a well-delined population o f high school rugby players (n.105) aged 13-17 years were monitored utilizing a prospective injury surveillance design with ail injury being defined as either requiring medical referral or causing a loss o f at least seven days from participation. risk factors were subsequently identified by anova, contrasting preparticipation musculoskeletal fitness profiles o f injured players with those o f tlie non-injured controls. results for injured vs non-injured players indicated a significantly (p<0,05) greater mean grip strength (70,5 ± 8,5 vs 64,9 ± 9,9 kg/kg:p<0,01); muscle power (15,3 ± 1,0 vs .1.4,3 ± 1,4w/ltg:p<0,001); and running agility (6,9 ± 0,4 vs 7,1 ± 0,4 sec:p<0,001). gross range o f motion variations in the shoulders (2,4 ± 0,3 vs 2,5 ± 0,3) did not differ significantly (p>0,05), but gross low-back/hamstring flexibility scores (3,5 ± 1,2 vs 2,9 ± 1,1) were significantly higher (p<0,05) among the exposed (injured) group. in conclusion tlie data suggests that superior musculoskeletal fitness among high school rugby players appears to predispose rather than preclude from injury. 63 the effect of upper respiratory t r a c t infection (urti) on exercise performance in distance runners d viljoen*, mp schw'ellnus facsm*, td noakes facsm*, m coetzee#. * sports m edicine, department o f physiology, university o f cape town, ♦department o f human movement sciencc, university o f zululand. runners suffering from urti who return to full activity after the post infection period frequently complain o f a decrease in performance. there are no scientific data to indicate whether i) there is a true decrease in performance, or ii) if such a decrease in performance is due to the effects of detraining or the infection. the aim o f this study was to determine the effects o f urti on exercise performance during recovery in distance runners. five distance runners were studied over four months. at the time o f recruitment, all runners underwent a medical assessment and baseline tests consisting of: i) run­ ning performance (voo peak in m l/kg/m in), ii) total treadmill time (mill), iii) quadriceps muscle strength (peak torque iu nm) and iv) quadriceps muscle endurance (total work, joules) were performed. all the subjects continued tlieir normal train­ ing program until thev developed an urti which was diag­ nosed clinically using a grading system (0 to +++) for symp­ toms (sore throat, headache, blocked nose, painful chest, cough, sore eyes, muscle pains) and signs (temperature, con­ junctivitis, pharyngitis, rhinitis, otitis media, rlionchii, wheeze). treatment consisted only o f medication for sympto­ matic relief. the runners were followed up regularly until recovery (defined as free from any symptoms or signs o f urti). recover)' time was variable (min=5 days, max=13 days, mean=7.8). following sickness (s), all tlie performance tests were repeated on days 0 (so), 2 (s2), 4 (s4), and 6 (s6). runners returned to normal training for 4 months after which they underwent a period o f voluntary detraining (d) for the same period as the urti. performance testing was repeated on days 0 (do), 2 (d2), 4 (d4) and 6 (d6). all parameters were compared during s and d days. there was a significantly lower voo peak (m l/ltg/inin) [mean(sd)] [so=53(8), do=59(7).| (p=0.026), and longer treadmill time (min) [so=5.2(2.5), do=6.8(2.2)] (p=0.03) at so compared to do. there was a sig­ nificantly lower v 0 2 peak [s2=54(7)), d2=58(7)j (p=0.04) at s2 compared to d2. there was no significant difference in muscle strength, or endurance at any time in s and d. in con­ clusion, runners recovering from urti appear to have a decrease in running performance but not muscle strength or muscle endurance which is not only due to detraining. however, this additional effect is temporary and lasts for 2-4 days after clinical symptoms have disappeared. 20 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 64. the treatment of plantar faschtis and achilles tendonitis by maintaining ankle dorstft exton using a night splint da viljoen, bsc, mbchb, da. richards bay, soulh africa. plantar fasciitis and achilles tendonitis are the most prevalent of lower limb injuries experienced by runners, and are notoriously resistant to conventional forms if treatment. an orthotie device which maintains ankle dorsiflexion and thus tension within the plantar fascii or achilles tendon (hiring sleep is thought to promote tissue healing at a functional length. the purpose o f this study was to optimise the design o f a locally' manufactured anterior fitting orthotie device and to determine the efficacy o f its use in treatment o f these chronic repetitive strain injuries. the optimum angles o f the device, were found to be 20" dorsiflexion and 15" forefoot valgus. distance runners with plantar fasciitis (n=19) and achilles tendonitis (n=f 5) o f grade 3 or 4 severity of, on average, 16 months duration were admitted to the study. all had received various forms o f medication, physiotherapy or both during this time. file control groups, who had lower limb injuries o f equal duration and severity were treated with a placebo orthotie and non-steroidal anti-inflammatory drugs (nsaids). for the 14 day study period the subjects were required to wear the orthotie during the night, to refrain from training and the use o f any other therapy. on days 0, 7 and 14 die severity o f pain experienced on arising was recorded on a scale o f 1 to 10. the presence o f pain on palpation and the extent o f tissue swelling were determined by the researcher on the same davs. the results show that in both groups who used the night splint, there was a significant reduction (p< 0.001) in the pain experienced on arising on both days 7 and 14. moreover, 36.8% o f those with plantar fasciitis and 49.7% with achilles tendonitis were able to walk pain free by day 14. however, most still experienced pain on palpation o f the injured site and more than half o f those with achilles tendonitis continued to exhibit marked tissue swelling on day 14. in both control groups there was no decrease in the degree o f pain experienced on rising, nor in the presence o f pain on palpation, by the end o f the study period. the results suggest that the use o f an anterior fitting night splint significantly aids recovery from chronic repetitive strain injuries o f the lower limb. 65 recovery techniques: a comparison of rest, stretching and massage. viranna n and mars m. dept, o f physiology, university o f natal medical school, durban, south africa. rapid and adequate recovery from exercise facilitates subsequent performance and reduces the associated symptoms o f tiredness, fatigue and lethargy. this study compares the effects o f three recover)' techniques, rest, stretching and massage in delaying fatigue during repeated bouts o f dynamic exercise, and investigates the relative effects o f rest, massage and stretching on delayed onset muscle soreness. method: 18 male subjects were randomly allocated to one o f six groups. subjects performed 5 repetitions o f as many heel raises as possible in 45 seconds. each repetition was followed by a recovery' technique used for the three minutes between repetitions. this was repeated weekly, until each group had had all three recovery' techniques. a fatigue index was calculated from the decline in the number o f repetitions from stage 1 to 5 and this was expressed as a percentage. muscle soreness ratings were assessed at 12 36 hours after each session. an orthogonal 6 x 3 latin square design was used to take into account possible training effect and the possible influence on the outcome o f the sequence in which the recovery techniques were used. results: based on the fatigue index, significantly more fatigue was shown when rest was the recover)' technique (p< 0.0001). there was no difference noted between stretching and massage. massage however associated with significantly less muscle soreness than stretching (p < 0.000 1). conclusions: rest was shown to be the least effective recover)' technique. while massage and stretching were shown to be equally beneficial in reducing fatigue, massage may be superior to stretching, as it is associated with less muscle soreness than stretching. further studies are required to confirm these observations using different m odes and intensities o f exercise. 66 skeletal muscle enzyme activities in african distance runners weston ar, karamizrak o, durandt j, smith a, noakes td, myburgli kii, department o f physiology, university of cape town, south africa. african athletes dominate distance running internationally and in south africa but to date only one study has investigated t he skeletal muscle enzyme profile in these. the aim o f the current study was to measure enzyme activity in the vastus lateralis muscle o f african 10 km runners in comparison to caucasian 10 km runners and sedentary controls. all subjects were seasoned runners (age range 18 35 yrs). 5 african and 7 caucasians consented to undergo two exercise tests and a muscle biopsy. runners completed a v02milx incremental treadmill test and on a separate day a fatigue resistance running test at four sequential high intensity workloads. on a separate day a muscle biopsy was performed. one portion was immediately frozen in liquid no for later enzyme assay's and the other embedded for later histochemistry. citrate synthase (cs) and phospliofruetokinase (pfk) were assayed in duplicate spectrophotometrically in all subjects, whilst 3-hydroxyl-coa dehydrogenase (3-had) hexokinase (hk) and carnitine palmityl transferase (cpt) were assayed in 7 subjects when sufficient tissue allowed. routine liistochemistry was undertaken to determine skeletal muscle fibre type. african runners were able to exercise for 21% longer at the same percentage o f their peak treadmill speed (p< 0.01). at submaximal worldoads, die african runners had a lower [lactate] and this was related to time to fatigue (r = -0. 63, p < 0. 05). cs activity was liigher in die african runners (27.9 ± 7.2 re 18.6 ± 2.1 inmol/g ww/min, p < 0.01) and limners were liigher than sedentary controls. 3-had activity was also higher in the africans (23.9 ± 4.7 vs 15.5 ± 5.1 nimol/g ww/min). pfk, hk and cpt were not different. cs activity was correlated with time to fatigue during die high intensity running test (r = 0.70, p< 0.05) and [lactate] during the running test (r = -0.73, p <0.01). the findings o f the current study suggest diat the african distance runners studied had advantageous skeletal muscle enzyme activities for endurance performance, and diat this activity is related to accumulation o f lactate in the plasma and dieir subsequent ability to sustain exercise at a high relative intensity. the origin o f tiiis advantageous enzyme profile is not elucidated. sports medicine march 1997 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) references a lii 11 13 j\nderson r 21 a n d erso n sj 1 b c o n sta n ce 2 8 b a s s e tt s 5 8 b a s so n ( j i beira b 2 b ellin ger b 5 7 b en gu x 13 b o sto n v 3 b ranfield a s 4 bridgev b 3 0 b n ntm an a j 5 b u x s 2 2 c p arry 2 8 .2 9 ('a id er s 14 c arter r 5 .6 .7 a 0 .5 0 ('h a n tler i 7 c h utu rgoon yl 2 2 .4 3 c olem an k l 8 ,9 coolc i 10 c ron s l 12 d en n is s 14. 2 5 d erm an e h ' <s\ 9. 13. 14. 15. 33. 34. 3(1 48. 5 2 d a b a isso n j 5 2 d u p lessis a 16 d t t p lo o y w.i 17 du randt j du toil 18. 19 etltrards t 18 e m m s m 8. 9 e van s a 4 8 farman r 1 forem an s 2 0 g abriels g 48 g eils i< i g o v en d er /4 a r 11 g o r e n d e r s.\ 2 2 g robelar l 14 iiattin e,b j ii 23. 24 h a w le y .i a 14. 25. 5(i lle g s t e k m,j 2 0 h irner m 2 7 llo llz h a its e n l 28. 29. 3 0 h u g h es ii 31. 3 2 h ugo j j 2 3 h ulse bl 33. 3 4 ilu rr x 19 lu th ier c p 17 k a ra n iir a k ( ) k en n ed y r 17 k han ,4 3 5 k iessiti m 3 6 k ir k b y r f 2 6 k o tr a s ii 3 7 lam bert e\’ 3 3 lam bert m i 38. 52. 56. 57. 6 0 l ategan l 3 9 l a irther b 4 0 l o o t s jm 3 9 lottrens . 1 3 9 m a cfarlane p\y 41 m ars m 20. 22. 3 5 . 42. 43. 55. 65 m ars s 4 3 m a ts e k e k o i > 13. 44 milligan j 5 3 m itchell g 5 m oller f 4 5 m othilal b 3 6 x a id o o d p 5 5 x ieo l j 46. 4 7 x ieuivoudt p 45 x o a k e s td 8. 9. 14. 21. 25. 33. 3 4 . 36. 46. 47. 48. 52. 53. 54. 56. 60. 6 6 o 's b a u g b n essy k 3 0 o elo fse r 5 7 o livier s 49 o o s lb u g s e t 5 0 o tto h' 13 palm er g 2 5 peroul j 5 6 p e ters e m 21 r aine r 9 k am atliesele j r 51 r o b ertso n g 3 7 r o sso tn r j 45 r o u x s 19 s ch eep ers k 5 2 schw artz p 13 schw ellnus m p 13. 14. 28. 29. 30. 31. 32. 36. 38. 44. 46. 47. 51. 53. 54. 6 3 sibbakl h 5 5 slogrove l 3 7 smith 8 sm ith i> 4 8 st clair g ibson . 1 14. 34. 56. 5 7 st claire sm ith o’ 9 s tretch r 18. 37. 5 8 stubbs j 3 6 terblancbe e 5 9 t erblanche s 6 0 theron a t 21 t itlesla d s 3 8 tow bridge t 2 7 trichard c 14 t y le r ,i 5 8 i an h eerden iij til. 6 2 van wgk g j 3 9 i an zyl e 54 i iljoen d 63. 64 viljoen iv 45 i iranna x 6 5 w aterm eyer g a 5 6 w essels j a 5 9 w eston a 22. 35. 55. 6 6 z am brasis m 14 22 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) msaiwajwi cm vs ba tired of hotels? in the heart o f camps bay this beautiful villa invites you to share its panoramic sea & mountain views. treat yourself & your overseas visitors to the privilege & luxury o f this outstanding villa in an exceptionally quiet street above the bay hotel. sundowners can be waiting on ice for your arrival. simply relax and enjoy watching the sun setting over the sea. introduce your visitors to a traditional south african braai or order the menu o f your choice to be delivered to you at msangasanga. special corporate offer upstairs & downstairs each w ith o w n lounge, dining room + kitchen downstairs: 2 bedroom s (both en suite) sleeps 4 • r800 pd. upstairs: 3 bedroom s (3 baths 2 en suite) sleeps 6 • r1200 pd. or 5 bedrooms (5 baths 4 en suite) • r2000 pd. • villa serviced daily • secure parking for 4 cars • phone + fax facilities • braai facilities • swimming pool • laundry service • 10 min to waterfront • catering services available • close to beach, shops & theatre for further information: tel: 27 (0)11 442-9759 • fax: 27 (0)11 880-7898 i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapists converge on cape town cape town will host two important international congresses during april 1997. the first is the international congress of the south african society of physiotherapy, from 31 march to 3 april, and the second is the congress of the international private practitioners’ association. the ippa is a division of the world confederation for physical therapy. more than 300 physiotherapists will attend tlie sasp congress, coming from countries as far afield as finland, america, zimbabwe, canada and australia. several countries in europe are represent­ ed. contributors from fourteen countries will present papers on physiotherapy research. community physiotherapy services are strongly represented in research papers by the 43 south african contributors, which also cover a wide variety of interests ranging from fetal movement studies to the causes of falling in the elderly. cape town is a fitting venue for the congresses, as the south african society of physiotherapy (sasp) has its origins hi a group who met in cape town in 1921 to form an association. the sasp itself was established in 1925 and is a fotmder member of the world confederation for physical therapy. cape town is bidding to host the 14th congress of the world confederation in 2003. the theme of the congress is physiotherapy in progress and the main fields covered are education, research, quality assurance, community physiotherapy, neurological rehabilitation and orthopaedic manipulative therapy. tlie organisers have been fortunate in attracting five internationally renowned keynote speakers. david butler of the university of south australia will speak in the field of orthopaedic manipulative therapy, which relates to conditions of the vertebral column and joints. patricia davies, the author of several well-lmown books, is the guest speaker on neurological reha­ bilitation. professor ruth grant, of the university of south australia, and professor katherine shepard of temple university, philadelphia, will speak on key issues in education and research respectively. the royal netherlands association for physiotherapy has sponsored the fifth keynote speaker, joost van eijkeren, as part of a twinning programme between themselves and the sasp which is committed to promoting quality assurance programmes in physiotherapy. for further information please contact sally elliott: tel: (0 2 1 ) 406-6381 fax: (0 2 1 ) 44 8-62 63 email: sally ©medicine, uct. ac.za 24 sports medicine march 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license analysis of goalkeepers’ game performances at the 2016 european football championships a kubayi, dphil (sport science) department of sport, rehabilitation and dental sciences, faculty of science, tshwane university of technology, pretoria, south africa corresponding author: a kubayi (kubayina@tut.ac.za) the primary function of a soccer goalkeeper is to defend his/her goal, while the secondary role is to initiate attack through ball distribution.[1,2] one of the greatest challenges a goalkeeper faces is that one mistake can cost the team its success. almost every situation in which the goalkeeper is called into play is a high-pressure event, as it may potentially be a losing or winning situation in the match.[1] thus, a goalkeeper needs to possess a unique physical and technical profile, and it is likely that further details about their match-play and training demands would benefit practitioners seeking to optimise a training prescription for this playing population.[2] over the last decade, technological developments have seen the implementation of increasingly advanced video and motion analysis systems for collecting data on the physical and technical demands of soccer players.[3] a number of studies has predominately focused on investigating the running demands of outfield players,[2-4] with players covering total distances of 8−12 km during a soccer game.[5] conversely, limited research has analysed the physical demands of soccer goalkeepers. a review by white et al.[2] demonstrated that goalkeepers cover total distances of four to six km during a match and appear not to experience between-half reductions in physical performance as the match progresses. in addition to the reduced distances covered by goalkeepers, research has also found that the majority of this distance is covered at low-intensity levels, such as walking or jogging.[6] with respect to comparisons between players, it has been found that goalkeepers performing at an international tournament spend approximately 98% of the game in the lowintensity threshold, compared to outfield players who spend approximately 83% of their time in this intensity zone.[7] furthermore, goalkeepers in the english premier league were found to only spend 1% of their time in high-speed running (i.e. between 19.9 and 25.2 km/h), which was accounted for by approximately 10 high-speed runs and two sprints of less than 10 metres (>25.2 km/h) per match.[6] while goalkeepers may only perform two short sprints per match, these actions could represent important phases of play directly related to key situations that can influence the score and outcome of the match.[2] despite there being few studies on the physical demands of goalkeepers in soccer matches,2,6 there is little information on the technical performance of goalkeepers during match-play. it is essential to consider the technical aspects of the goalkeepers [4,6] because this information can better predict successful team performance in soccer compared to purely physical parameters.[8] therefore, research on both physical and technical performances of goalkeepers could assist soccer coaches to better understand their specific match-related activities and training programmes can be modified appropriately.[3,4] the purpose of this investigation was to analyse the game performance profiles of goalkeepers at the european football championships. methods match sample and data collection a total of 30 goalkeepers from 15 games played during the 2016 european football championships were analysed using the instat® video tracking system (https://instatsport.com/ football). match activities were recorded using two video cameras installed on tripods set at the end of each stand. video recordings from each camera fully covered separate halves of the field. the reliability of the instat® tracking system has been demonstrated in previous research.[9] ethical clearance was received from the author’s institutional ethics committee. physical and technical indicators physical indicators of goalkeepers were categorised as follows: (a) walking (0–7 km/h), (b) jogging (7.1–14.5 km/h), (c) running (14.6–20 km/h), (d) high-speed running (20.1–25 km/h) and (e) sprinting (>25 km/h). high-intensity activity was defined as background: despite a substantial body of literature on the physical and technical demands of outfield players in football, there is little information regarding the performance of goalkeepers. objective: the aim of this study was to analyse the game performance profiles of goalkeepers at the 2016 european football championships. methods: a total of 30 goalkeepers from 15 games played during the 2016 european football championships were analysed using the instat® video tracking system. results: the results showed that goalkeepers covered a mean total distance of 4819 m, ranging from 4036 m to 6640 m. overall, 68% of distance travelled was attributed to walking, whereas 0.8% was due to high-intensity activities. the goalkeepers of teams that lost matches covered significantly (p < 0.05) longer distances while sprinting than those of teams that drew or won the matches. goalkeepers of teams that drew significantly (p < 0.05) had a greater number of passes than those goalkeepers of teams that won or lost. conclusion: the current results have implications for soccer coaches to structure training sessions and tactical strategies for goalkeepers. the ability of goalkeepers to meet the physical and technical demands of a match could directly influence the successful execution of skills and the outcome of the competition. keywords: physical performance, distance, technical skills, matches s afr j sports med 2020;32:1-4. doi: 10.17159/2078-516x/2020/v32i1a8283 https://instatsport.com/%20football https://instatsport.com/%20football http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8283 https://orcid.org/0000-0002-8370-3056 original research sajsm vol. 32 no. 1 2020 2 high-speed running and sprinting (>20.1 km/h). distances in attack and defence were calculated according to whether the goalkeeper was in possession of the ball or not. all distances in various categories were combined to calculate the total distance covered. the technical indicators included variables such as save (the goalkeeper prevents the ball from entering the goal with any part of his body), pass (an intentional played ball from the goalkeeper to his teammate, including ball throwing from the hand), pass accuracy (%) (a ratio calculated from successful passes divided by all passes), aerial duels won (%) (two players competing for a ball in the air – for it to be an aerial duel, both players must jump and challenge each other in the air and have both feet off the ground), tackle (act of gaining possession from an opposition player who is in possession of the ball), lost ball (the goalkeeper lost ball possession due to a mistake/ poor control, including turnovers, dispossession, and unsuccessful passes), ball recovery (the event given at the start of a goalkeeper’s recovery of ball possession from opponents from open play), foul drawn (where the goalkeeper is fouled by an opponent), and yellow-card (where the goalkeeper is booked by the referee due to illegal actions).[4,10] statistical analysis data were reported as means ± standard deviations. oneway analysis of variance was used to examine differences on the physical and technical parameters of goalkeepers based on match outcomes (i.e. win, lose or draw). in addition, if the f-ratio was significant at p≤0.05, then tukey’s hsd post hoc analysis was conducted. the effect size (es) was used to determine the magnitudes of the studied variables. es was grouped as follows: trivial (<0.20), small (0.20–0.59), moderate (0.60–1.19), large (1.20–2.00), and very large (>2.00). [11] all analyses were computed using the ibm statistical package for the social sciences (spss), version 25.0. results table 1 presents descriptive characteristics of distances covered at different intensities by goalkeepers. the mean total distance covered by goalkeepers was 4819 m (range = 4036 m to 6640 m). walking accounted for 68% of distance travelled during matches, with only 0.8% of distance covered spent in high-intensity activities, such as high-speed running and sprinting. there were minimal differences in the distances covered during the first half (2412 ± 281 m) and second half (2408 ± 323 m) of matches, with trivial effect (es = 0.01). goalkeepers covered longer distances during attacking phases of play (1660 ± 463 m), compared with defending (1569 ± 436 m) phases (es = 0.20, small effect). table 1. the mean distances (m) covered by goalkeepers during a match relative to the different intensities, game period and phases of play (n=30) mean standard deviation minimum maximum total distance (m) 4819 580 4036 6640 walking 3277 367 2590 3990 jogging 1272 395 744 2127 running 230 108 81 569 high-speed running 39 28 11 113 sprinting 2.2 6.5 0 30 first half 2412 281 2048 3080 second half 2408 323 1971 3560 in defence 1569 436 881 2645 in attack 1660 463 874 2767 m, metres table 2. physical and technical indicators of goalkeepers according to the match outcome (n=30) win lose draw significance (p-value) physical indicators total distance (m) 4808 ± 433 4787 ± 771 4880 ± 522 0.94 walking (m) 3247 ± 448 3267 ± 292 3333 ± 380 0.88 jogging (m) 1304 ± 285 1241 ± 448 1272 ± 491 0.94 running (m) 231 ± 83 231 ± 135 226 ± 112 0.99 high-speed running (m) 27 ± 16 43 ± 32 49 ± 31 0.20 sprinting (m) 0.0 ± 0.0 6.0 ± 9.9# 0.0 ± 0.0 0.04* in defence (m) 1480 ± 423 1432 ± 354 1880 ± 447 0.06 in attack (m) 1518 ± 305 1591 ± 529 1953 ± 466 0.10 technical indicators save (n) 4.6 ± 2.5 3.8 ± 1.7 2.9 ± 2.0 0.21 pass (n) 29 ± 9 28 ± 8 40 ± 9# 0.01* pass accuracy (%) 87 ± 4 88 ± 9 89 ± 6 0.83 aerial duel won (%) 64 ± 51 18 ± 41 13 ± 35 0.21 tackle (n) 0.09 ± 0.30 0.18 ± 0.40 0 ± 0 0.45 lost ball (n) 3.3 ± 1.4 2.9 ± 2.8 3.3 ± 2.0 0.90 ball recovery (n) 5.6 ± 2.0 5.5 ± 3.0 6.6 ± 4.0 0.68 foul drawn (n) 0.09 ± 0.30 0.18 ± 0.40 0.25 ± 0.46 0.68 yellow card (n) 0.09 ± 0.30 0 ± 0 0 ± 0 0.44 data are expressed as mean ± standard deviation. *significant at p<0.05; #significantly higher than other teams at p<0.05. m, metres; %, percentage; n, number original research 3 sajsm vol. 32 no. 1 2020 table 2 shows distances covered by goalkeepers at different intensities, as well as technical indicators based on match outcome. goalkeepers of teams that lost covered significantly greater distances while sprinting (6.0 ± 9.9 m) compared with those of teams that drew or won games (f [2, 27] = 3.48, p = 0.05). post hoc comparisons showed that the mean score for a sprinting distance of goalkeepers of teams that lost was significantly higher than for teams that won or drew. goalkeepers of teams that drew covered greater distances associated with walking (3333 ± 380 m) and high-speed running (49 ± 31 m). goalkeepers of the teams that won covered longer distances when defending (1480 ± 422 m), while those of teams that lost (1591 ± 529 m) or drew (1953 ± 466 m) covered greater distances associated with attacking phases. with regard to the technical variables, a statistically significant difference was observed on passes (f [2, 27] = 4.61, p = .01). the post hoc comparisons showed that the mean score of the passes for the goalkeepers of teams that drew (40 ± 9) was significantly different from those of teams that won (29 ± 8, es = 1.21, large effect) or lost (28 ± 8, es = 1.45, large effect). goalkeepers of teams that won had a higher number of aerial duels won, albeit not significant, than those of teams that lost (es = 1.71, large effect). discussion the aim of this study was to analyse the game performance profiles of goalkeepers at the 2016 european football championships. regarding physical parameters, goalkeepers covered an average total distance of 4819 m during a match. this result is lower than that of previous findings, which reported that goalkeepers covered a total distance of 5611 m during match-play.[6] the current study demonstrated that there are minimal differences between the halves of the game in terms of the distance covered by goalkeepers. this observation is consistent with that of di salvo et al.[6] who found that the physical performance for goalkeepers is mirrored across the two halves. regardless of variations between studies, these distances represent about 50% of those covered by outfield players and may explain why no betweenhalf declines in total distance have been observed within any intensity threshold for international goalkeepers.[2] as indicated in previous studies,[2,6] goalkeepers walked for 68% of the total match duration and spent only 0.8% of the match in high-intensity activities. this finding suggests that as goalkeepers work in a limited space (i.e. in the defensive penalty area), it may be difficult for them to display a large number of high-intensity actions during a match.[6] despite their low high-intensity running distances, this may, however, represent actions which can have a direct influence on the outcome of a match,[2] and therefore coaches should design training sessions involving high-intensity, game-specific activities. regarding running performance and match outcome, the finding that the goalkeepers of the teams that lost covered significantly greater distances in sprinting compared to the goalkeepers of the teams which won or drew, could be explained by the fact that they may push forward when losing, thus reaching their maximal physical capacity in the hope of potentially drawing or winning the game.[12] the present data further showed that goalkeepers of teams that drew covered a greater distance in the defending phases of play than those of the teams that lost or won. from a defensive perspective, this finding could be associated to the fact that teams that draw may adopt a more defensive strategy to ensure that they do not concede and potentially lose the game. in this context, players may adopt a ball retention strategy,[13] which could result in higher distance covered when defending during a match. maintaining possession of the ball is one of the most physically demanding playing styles because, if executed appropriately, players (including goalkeepers) may have to expend more energy during a match.[14] furthermore, the goalkeepers of teams that drew or won had a greater number of passes than those of teams that lost. in modern soccer, goalkeepers need to be proficient in their ball control skills, such as passing, so that without the option to use their hands, back-passes from teammates are secured to better deal with opponent pressure.[15] goalkeepers of teams that won had a higher number of successful aerial duels, with a large magnitude, compared to the goalkeepers of teams that lost or drew. liu et al.[10] reported that teams which are effective in dealing with aerial duels are more likely to dominate both the attacking and defending phases, eventually leading to a match win. conclusion this study suggests that goalkeepers perform most match activities at a low intensity, with only a small proportion of actions executed at high-intensity. goalkeepers of teams that lost covered significantly greater distances while sprinting compared to those of the teams that drew or won. the goalkeepers of teams that won had a higher number of ball recoveries than those of teams that lost and won. therefore, the results of this study are important for soccer coaches in designing training programmes for goalkeepers so that they can meet the physical and technical demands of a game which could directly influence the competition’s outcome. conflicts of interest and source of funding: the author declares that they have no conflict of interest and no source of funding. references 1. seaton m, campos j. distribution competence of a football clubs goalkeepers. int j perform anal sport 2011; 11(2):314324. [doi: 10.1080/24748668.2011.11868551] 2. white a, hills sp, cooke cb, et al. match-play and performance test responses of soccer goalkeepers: a review of current literature. sports med 2018; 48(11): 2497-2516. [doi: 10.1007/s40279-018-0977-2] [pmid: 30144021] 3. spalding j. technical and physical match demands of a ncaa division i soccer goalkeeper. master’s thesis. paper 3176. east tennessee state university, united states of america, 2017. https://dc.etsu.edu/etd/3176. 4. liu h, gómez má, lago-peñas c. match performance profiles of goalkeepers of elite football teams. int j sports sci coach 2015; 10(4): 669-682. [doi:10.1260/1747-9541.10.4.669] original research sajsm vol. 32 no. 1 2020 4 5. kubayi a. evaluation of match-running distances covered by soccer players during the uefa euro 2016. s afr j sports med 2019; 31(1): 1-4. [doi: 10.17159/2078516x/2019/v31i1a6127] 6. di salvo v, benito pj, calderón fj, et al. activity profile of elite goalkeepers during football match-play. j sport med phys fitness 2008; 48(4): 443-446. [pmid: 18997646] 7. clemente fm, couceiro ms, martins fm, et al. activity profiles of soccer players during the 2010 world cup. j hum kinet 2013; 38: 201-211. [doi:10.2478/hukin-2013-0060] [pmid24235995] 8. rampinini e, impellizzeri fm, castagna c, et al. technical performance during soccer matches of the italian serie a league: effect of fatigue and competitive level. j sci med sport 2009; 12(1): 227-233. [doi: 10.1016/j.jsams.2007.10.002] [pmid:18083631] 9. dmitriy a, mike n, ilya v, et al. validation and precision analysis of instat fitness system. instat 2013; 1-14. 10. liu h, hopkins wg, gómez ma. modelling relationships between match events and match outcome in elite football. eur j sport sci 2016; 16(5): 516-525. [doi: 10.1080/17461391.2015.1042527] [pmid: 26190577] 11. batterham am, hopkins wg. making meaningful inferences about magnitudes. int j sports physiol perform 2006; 1(1): 5057. [doi: 10.1123/ijspp.1.1.50 ] [pmid: 19114737] 12. castellano j, blanco-villaseñor a, alvarez d. contextual variables and time-motion analysis in soccer. int j sports med 2011; 32(6): 415-421. [doi.org/10.1055/s-0031-1271771] [pmid 21590641] 13. bloomfield jr, polman rc, o’donoghue pg. effects of scoreline on intensity of play in midfield and forward players in the fa premier league. j sports sci 2005; 23(2): 192-193. 14. kubayi a, toriola a, paul y. the effects of ball-possession status on technical and physical indicators at the 2016 european football championship. med dello sport 2018; 71(4): 533-539. [doi: 10.23736/50025-7826.18.03396-3] 15. carling c, williams am, reilly t. the handbook of soccer match analysis: a systematic approach to improving performance. london: routledge, 2005, pg 94. https://doi.org/10.2478/hukin-2013-0060 https://doi.org/10.2478/hukin-2013-0060 https://doi.org/10.1016/j.jsams.2007.10.002 https://doi.org/10.1016/j.jsams.2007.10.002 https://doi.org/10.1080/17461391.2015.1042527 https://doi.org/10.1080/17461391.2015.1042527 https://doi.org/10.1123/ijspp.1.1.50 https://doi.org/10.1055/s-0031-1271771 original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license training and match load in professional rugby union: do contextual factors influence the training week? sw west,1,2 phd; s williams,1 phd; p tierney,3 msc; t batchelor,4 msc; mj cross,5 phd; spt kemp,6,7 mbbs, msc; ka stokes,1,6 phd 1 department for health, university of bath, bath, uk 2sport injury prevention research centre, faculty of kinesiology, university of calgary, calgary, canada 3 the football association, burton-on-trent, uk 4 harlequins rugby union, twickenham, uk 5 premier rugby limited, twickenham, uk 6 rugby football union, twickenham, uk. 7 london school of hygiene and tropical medicine, uk corresponding author: sw west (stephen.west@ucalgary.ca) training for sport is the process of applying stressors to the body to improve physical and tactical capacity and sporting performance.[1, 2] training loads are prescribed with the aim of inducing physiological change and must be applied periodically to align with the individual needs of the athlete, the tactical requirements, and the competitive demands of the sport. when preparing for the demands of rugby union, a multifaceted programme must be used, given the broad range of physical and technical attributes required.[3] such a programme typically includes components of rugby skills (full, semiand non-contact), as well as conditioning strategies.[4] athlete load monitoring has become a regular part of most professional sporting environments, with measures of both external and internal load typically used to determine the ‘dose-response’ relationship to training and matches.[4, 5] in rugby union, a broad range of measures are used, including session rating of perceived exertion (srpe) and global positioning systems (gps).[6] on average, premiership rugby players in england undertake 6 hrs 48 min (95% cis: 6 hrs 30 mins 7 hrs 4 mins) of training each week [7]; however, how this volume is distributed across the training week, and the types of training undertaken are not well described. in football, the distribution of load across the week demonstrates that matches represent the highest ‘dose’, with the load declining in the three days prior to each fixture.[8] the periodisation of weekly training in rugby union is likely to be similar; however, studies of this type in rugby union are scarce. further to this, studies in other sports outlining the weekly training structure often include just one team and therefore represent the preparation strategies of just that one team[8, 9], meaning generalisability to the wider playing population is low. the lack of published data in this area is likely due to the reluctance of elite teams to publish data to retain a competitive advantage.[8] while training load is individually prescribed and specific to the timing of the match, a number of contextual factors may also play a role in the prescription of training throughout a week. these contextual factors include the standard of the opposition, the result in the previous fixture, match location and competition type.[10] in rugby union, one further contextual factor that has been reported is that of surface type [11], with several professional teams reporting an alteration to match preparation based on playing on artificial surfaces compared with natural grass. given the potential influence of these factors on training, this study aims (i) to describe the weekly structure of training using both internal and external measures of training load, and (ii) to investigate the association between contextual factors and weekly training load in a cohort of english professional rugby union clubs. methods participants during the 2017/18 season, 397 players consented to partake in this study from six english premiership teams (the highest level of rugby union in england). the participants were provided with information regarding the study before signing individual consent forms as approved by the research ethics approval committee for health at the university of bath (ref: 15/16 252). background: rugby union demands a multifaceted approach to training, given the multiple physical and technical attributes required to play the sport. objectives: the aim of this study is to describe the distribution of training throughout the week and investigate how this may be influenced by match-related factors. methods: training load data (session rating of perceived exertion [srpe], total distance and high-speed running [hsr]) were collected from six professional english rugby teams during the 2017/18 season. five contextual factors were also recorded including: standard of opposition, competition type, result of previous fixture, surface type, and match venue. results: the day prior to matches demonstrated the lowest training load (101 au (95% cis: 0-216 au) , 1 047 m (95% cis:1 128-1 686 m) and 59 m (95% cis: 0-343 m), respectively), while four days prior to the match demonstrated the highest training load (464 au (95% cis: 350-578), 2 983 m (95% cis: 2 704-3 262m) and 234m (95% cis: 0-477m), respectively). of the five contextual factors, competition type was the only variable that demonstrated greater than trivial findings, with training before european fixtures the lowest stimulus across the four different competition types. standard of opposition, previous result, surface type and venue had only trivial effects on training load (effect sizes = -0.13 to 0.15). conclusion: future studies should outline the distribution of other training metrics, including contact and collision training. this study provides a multi-club evaluation that demonstrates the variety of loading strategies prior to competitive match play and highlights competition type as the most influential contextual factor impacting the average training load. keywords: athlete management, training load, athlete, injury prevention, performance s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a9509 mailto:stephen.west@ucalgary.ca http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9509 https://orcid.org/0000-0003-1460-0085 https://orcid.org/0000-0001-5800-7000 https://orcid.org/0000-0002-6216-9368 https://orcid.org/0000-0002-3250-2713 https://orcid.org/0000-0002-5049-2838 original research sajsm vol. 33 no. 1 2021 2 procedures for each of the 397 players in the study, daily training load data were recorded by sport science/ conditioning staff at each club. these data were collected as per normal daily monitoring practices. following an initial pilot study to select common variables[6], two measures were selected to be included as external load markers (high-speed running (hsr) and total distance), as well as one internal load measure, session rating of perceived exertion (srpe)[12]. the clubs included in the study were taken from a wider population of twelve teams across the competition and were selected because they used hsr and total distance derived from the same gps provider (catapult, catapult sports, australia). of the teams included in the study, two did not consistently collect srpe data on match days and one did not consistently collect total distance data. this meant they were excluded from the analysis for each of those respective variables as the inconsistent collection of data rendered the data unsuitable for inclusion in this study. only clubs using relative hsr (thresholds defined by a percentage of each individual player’s maximum velocity) were included in the final analysis (due to difficulty comparing relative and absolute values); however, given the desire to not impose timeconsuming data collection procedures on the club staff, each club’s own definition of high-speed running was used. this meant a range of thresholds for high-speed running were used, (>60% vmax for two clubs, >70% vmax for one club, and 40-70% of vmax for the final club). the use of differing hsr thresholds across teams did not impact on the main research objectives, as the statistical analyses assessed the influence of contextual factors and weekly periodisation within teams/players. statistical analysis data were recorded for all match and training days and only the data of players who participated in that week’s match were included in the analysis of the team’s preparation for that game. to identify underlying associations between the training load variables, a pearson product-moment correlation was calculated between srpe/total distance, srpe/hsr and total distance/hsr. correlation coefficients were interpreted using the following classification (0.9 to 1.00: very high, 0.70 to 0.90: high, 0.50 to 0.70: moderate, 0.30 to 0.50: low, .00 to 0.30: negligible) [13]. average training load values for match day (md) and each day prior (md-1, md-2, md-3, md-4, md-5) were calculated for srpe, total distance and hsr variables for all players included in the fixture for that week. to understand potential contextual factors that may have influenced the weekly prescription of training load in this sample, several other factors were included: opposition final season ranking (proxy measure for opposition standard), competition (premiership, friendly, european, national cup), result of previous fixture (win/loss/draw), surface type in next match (artificial turf or natural grass), and venue for the game (home/away). linear mixed models were used to assess the differences between each preparation day on the respective training load metrics. each of the contextual variables were included as fixed effects, with random effects included for each player within their respective teams. analyses were undertaken using the lme4 package[14] in rstudio (rstudio, inc. version 1.1.463). estimated marginal means (emms) were calculated alongside corresponding 95% confidence intervals for each respective variable of interest, with differences assessed using effect sizes, confidence intervals and p-values using the emmeans package[15]. effect sizes were interpreted using cohen’s effect sizes (<0.2: trivial, 0.2 0.5: small, 0.5-0.8: medium, >0.8: large [16]). results over the study period, 128 332 days of training were recorded (excluding days off) across the six teams involved in the study. on examination of the training load variables, srpe and total distance variables were deemed to have a moderate correlation (r =0.66 (95% cis: 0.65-0.67)), srpe and hsr a weak correlation (r =0.32 (95% cis: 0.30-0.34)) and total distance and hsr a moderate correlation (r = 0.62 (95% cis: 0.61-0.63)). weekly distribution of training load across all training load metrics (srpe, total distance and hsr), the match day represented the highest average per player with a mean of 513 au (95% cis: 398-629 au), 4 209 m (95% cis: 3 929-4 488 m) and 390 m (95% cis: 146-633 m), respectively (table 1). match-day-1 (md-1) represented the lowest training load of the five days preparation for games (101 au (95% cis: 0-216 au), 1 047 m (95% cis: 1 128-1 686 m) and 99 m (95% cis: 0-343 m), respectively, while the day with the highest load outside of the match exposure was md-4 (464 au (95% cis: 350-578 au), 2 983 m (95% cis: 2 704-3 262 m) and 234 m (95% cis: 0-477 m) respectively shown in table 1). modelling the differences between match day exposure and each respective training day demonstrated large differences, with the exception of md-4 which showed trivial differences between match day and training for srpe and medium differences for total distance and hsr. the biggest differences were seen between match day and md-1 across all variables (effect sizes: srpe: 1.37, total distance: 1.42 and hsr 1.12 respectively, shown in table 2). standard of opposition using a team who finished 1st or 2nd during the season (high standard of opposition) as the reference group, only trivial effects on srpe training load were seen in the days prior to a match (see table s2). similarly, for both the total distance and hsr, only trivial effects were found based on standard of opposition (see tables s3/s4). competition type european fixtures were used as the reference category for comparisons between competition types. for srpe, trivial differences were found between european, national cup and premiership fixtures. however, small negative effects were seen between european fixtures and friendlies (es = -0.30, 95% cis: -0.36 to -0.25, p<0.001) with players undertaking an average of 245 au of training load per day on european weeks compared with 337 au during the weeks of friendly games (see original research 3 sajsm vol. 33 no. 1 2021 tables s1/s2). for total distance, european fixtures demonstrated the lowest daily averages across all competition types (1 881 m), with small significant effects seen when compared to national cup and premiership fixtures (es = 0.27 for both comparisons) but only trivial effects when compared with friendlies (see tables s1/s3/s4). high-speed running demonstrated only trivial changes based on competition type. follow-up analysis demonstrated that premiership games had the highest match load for srpe (median: 560 au, iqr: 300-720 au), national cup games demonstrated the highest median total distance covered in a game (median: 4 519 m, iqr: 2 304-6 355 m) and premiership games demonstrated the highest median hsr distances (median: 240 m, iqr: 96-541 m: see table s5). previous result, surface type, and venue the outcome of the previous game (win or loss) demonstrated only trivial effects on training load in the subsequent week across all training load measures (see tables s2/s3/s4). the surface type on which the upcoming game would be played (natural grass or artificial turf) demonstrated only trivial effects on the training load in the preceding week across all training load measures (see tables s2/s3/s4). finally, the location of the upcoming game (home vs. away) demonstrated only trivial effects on training load across all three training load variables (see tables s2/s3/s4). discussion this study is the first to objectively examine the distribution of training across a week in professional rugby union. the match day itself demonstrated the highest average load, while four days prior to the match (md-4) demonstrated the greatest training stimulus, based on the srpe, total distance, and hsr metrics. the day with the lowest training exposure and therefore the day with the largest effect size compared with match days was the day before a game (md-1: effect sizes 1.121.42). when examining training prior to different competition types, european fixtures demonstrated lower average training loads for srpe compared to friendlies and lower total distance values compared with premiership and national cup fixtures. of the other remaining contextual factors considered, none demonstrated more than trivial changes in the average load per player in the days prior to a match. what is the structure of a training week? it has been previously shown that professional rugby players train an average of 6 h 48 min (95% cis: 6 h 30 min 7 h 4 min) per week.[7] while this is useful for understanding weekly volume, it is imperative to understand the intensity and how table 1. mean (95% cis) player training load distribution across a week md-5 md-4 md-3 md-2 md-1 md session rating of perceived exertion (au) 185 (71-300) 464 (350-578) 160 (46-275) 241 (127-355) 101 (0-216) 513 (398-629) total distance (metres) 1 298 (1 019-1 577) 2 983 (2 704-3 262) 1 226 (947-1 505) 1 995 (1 716-2 274) 1 407 (1 128-1686) 4 209 (3 929-4 488) high-speed running (metres) 142 (0-385) 234 (0-477) 108 (0-351) 155 (0-399) 59 (0-343) 390 (146-633) md, match day; md-1, 1 day prior to match; md-2; 2 days prior to match; md-3, 3 days prior to match; md-4, 4 days prior to match; md-5, 5 days prior to match table 2. effect size (95% cis), p-value, and effect size interpretation of modelled difference between match day and each respective training day measure md to md-5 md to md-4 md to md-3 md to md-2 md to md-1 session rating of perceived exertion (au) effect size 1.09 (1.03-1.14) 0.16 (0.11-0.22) 1.17 (1.12-1.23) 0.90 (0.85-0.96) 1.37 (1.31-1.42) p-value <0.001 <0.001 <0.001 <0.001 <0.001 effect size interpretation large small large large large total distance (metres) effect size 1.48 (1.44-1.52) 0.62 (0.58-0.66) 1.52 (1.48-1.56) 1.13 (1.09-1.17) 1.42 (1.38-1.46) p-value <0.001 <0.001 <0.001 <0.001 <0.001 effect size interpretation large moderate large large large high-speed running (metres) effect size 0.95 (0.91-1.00) 0.60 (0.55-0.64) 1.09 (1.04-1.13) 0.90 (0.85-0.94) 1.12 (1.07-1.16) p-value <0.001 <0.001 <0.001 <0.001 <0.001 effect size interpretation large moderate large large large md, match day; md-1, 1 day prior to match; md-2; 2 days prior to match; md-3, 3 days prior to match; md-4, 4 days prior to match; md-5, 5 days prior to match original research sajsm vol. 33 no. 1 2021 4 training is distributed throughout the week. the training structure of a professional rugby union team has previously been shown for the five days prior to competitive matchplay[9]; however, only weekly totals of training load for srpe and gps metrics were presented, meaning that the distribution of load within the individual sessions was not clear. the current study builds on the available research to demonstrate the typical distribution of training throughout the week. given the highly attritional nature of professional rugby union, the frequency of matches is typically limited to one per week, usually with a minimum of a five-day turnaround between games. this study has shown that the greatest training stimulus in preparation for games is that of md-4, which had an average srpe of 464au (350-578), average total distance of 2 983 m (2 704-3 262) and average hsr of 234 m (0-477) per athlete. unsurprisingly, the day prior to a game (md-1) had the lowest training stimulus. this reduced load on md-1 aligns with evidence in rugby union, as well as football, reporting a decline in training load in the days prior to matches[8, 9]. is the weekly structure between teams similar? fig. 1 demonstrates the differences between clubs in their approach to the weekly distribution of load and highlights the fig. 1. club by club median player training load distribution across a week. a) session rating of perceived exertion (srpe) load b) total distance (td) derived from global positioning system (gps) c) high-speed running (hsr) derived from gps. each bar represents a different club. md: match day, md-1: 1 day prior to match, md-2: 2days prior to match, md-3: 3days prior to match, md-4: 4days prior to match, md-5: 5days prior to match. a) only four clubs provided suitable data for srpe and to avoid inflated or deflated scores, two clubs were removed from this analysis. b) one club provided unsuitable data and was removed from the td analysis. c) two clubs provided unsuitable data and were removed from the hsr analysis. medians include all players involved in matches in that week (irrespective of whether they partook in every session). original research 5 sajsm vol. 33 no. 1 2021 importance of including multiple teams in descriptive studies of this type. this is required to adequately portray the different conditioning strategies employed by staff and highlights the lack of a ‘one size fits all’ approach. largely, the structure of the training week was similar between clubs, with some clubs employing a slightly different structure, electing to take rest days on different days. previous studies have generally been limited to a single club, giving rise to the potential for club specific practices to influence the weekly structure.[8, 9] this study included data from six teams across the same league and therefore decreases the likelihood of the results to be representative of just one club. one of the most substantial differences between clubs is that of the values associated with high-speed running. however, as outlined previously, this study used a hsr defined by each club, which included a range of values, for example, one club defining hsr as 40-70% vmax, compared with others which included >70% vmax. the influence of contextual factors on training load despite both empirical evidence in football[10] and anecdotal evidence in rugby union in this study, contextual factors, including standard of opposition, previous result, surface type and venue, had only trivial effects on the training load of players. of the included contextual factors, only the competition type demonstrated an effect, with european fixtures being preceded by the lowest average training loads per player per day for srpe, total distance and hsr. as friendly fixtures are largely reserved for the pre-season period, the finding linked to srpe is unsurprising, given that it has been previously shown that during the pre-season period, training volume is higher than in-season (9 h per week vs, 6 h 6 min per week).[7] with the pre-season period designed to prepare players for the season, weekly training volumes will often be higher to improve fitness, giving rise to the higher srpe load. given the difference between the european fixtures and friendlies this was greater for srpe and not total distance and hsr metrics, suggesting that either a greater amount of gym-based training is undertaken during the preseason or the internal load produced by the external load is higher in pre-season due to lower fitness levels.[7] for both of the gps-based running metrics, significantly lower training was shown to be undertaken in the weeks prior to european fixtures compared with that of the premiership and national cup fixtures, which suggests a tapering strategy prior to important european fixtures. however, it is important to consider that in some cases, (when the outcome of a group in the competition is already decided), games become less important and therefore teams may use these weeks as an opportunity for lower training loads in anticipation of future fixtures. which is the most physically demanding competition and why do external and internal loads not match up? while not a primary aim of this study, the disparity between subjective internal load (srpe) and objective external load is particularly interesting. the wide interquartile range suggests a broad spectrum of values are likely and the median values demonstrate that, based on srpe and hsr, premiership fixtures provide the highest match load stimulus. however, based on total distance, national cup fixtures represent the highest match load stimulus. as the leading national and international competitions, it would be expected that the premiership and european cup would elicit the highest match loads and, therefore, the finding that the national cup represented the highest total distance load was surprising. however, it is possible that the the weekly competition may influence squad selection and game-related factors that may be associated with increased ball in play time, greater time spent in offense vs. defence, and other patterns of play. further work to understand why these differences occur would help to differentiate between match demands and their association with competition type. compared with data from a similar cohort, the total distance values associated with match play (median: 4 483 m, iqr:2 069-6 478) were lower than those previously reported (5 581 m ± 692 for forwards, 6 127 m ± 724 for backs).[17] however, roberts et al.[17] normalised their data to 80 minutes of play per position, whereas in the context of this study, the data showed the average distance covered per player that partook in the game for any period of time, which explains the difference in the total distance covered. limitations a significant limitation of this study is the exclusion of collision-based metrics. collision is a significant component of both training and match physical stimulus and therefore its omission is important to recognise. however, given the pilot work that was undertaken in advance of this study, the methods and consistency with which collision is collected across clubs was not considered sufficient to make broader conclusions than on a club-by-club basis.[6] secondly, the present study reported match data as the average value per player involved in the game for any period of time and therefore, includes players who had only played for short periods of time, as well as full matches. in addition, as this was a multi-club study where each club used the available technology in different ways, which led to differences in not only the definitions used in the hsr variables but also some clubs data being unusable due to certain metrics not being collected on certain days (e.g. srpe on a match day). while this is a limitation of the study, given the multi-club nature and the desire to represent the data as used in daily practice, these methods were used and accounted for in any analysis through the use of generalised linear mixed models, including random effects for each player within their club. conclusion this study outlines the training distribution of teams in preparation for professional rugby union matches. strengthened by the inclusion of data from multiple clubs, the generalisability of the data to other professional rugby environments is useful. as per other team sports, daily training load in the day preceding a match exposure is lowest across the week, with md-4 demonstrating the highest training stimulus for running and perceived exertion, recognising that contact original research sajsm vol. 33 no. 1 2021 6 demand will likely differ substantially. there is a need for further investigation into the distribution of collision and contact training throughout the week, but this study provides an overview of weekly preparation for competitive professional rugby union. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: conception and design of the study was led by swe, swi, mjc, sptk and kas, analysis was undertaken by swe, swi and kas and the interpretation of data was undertaken by all authors on the study, with critical practical insights from pt and tb. drafting of the manuscript was led by swe, swi and kas with critical revision for important intellectual content from all authors. approval of the final version of the manuscript was received from all authors. references 1. meeusen r, duclos m, foster c, et al. prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the european college of sport science and the american college of sports medicine. med sci sports exerc 2013;45(1):186-205. [doi: 10. 1249/mss.0b013e318279a10a] [pmid: 23247672] 2. soligard t, schwellnus m, alonso jm, et al. how much is too much? (part 1) international olympic committee consensus statement on load in sport and risk of injury. br j sports med 2016;50(17):1030-1041. [doi: 10.1136/bjsports-2016-096581] [pmid: 27535989] 3. tee jc, lambert mi, coopoo y. gps comparison of training activities and game demands in professional rugby union. int j sports sci coach 2016;11(2):200-211. [doi:10.1177/ 1747954116637153] 4. west sw, clubb j, torres-ronda l, et al. more than a metric: how training load is used in elite sport for athlete management. int j sports med 2021; 42(4): 300-306. [doi: 10.1055/a-12688791][pmid: 33075832] 5. impellizzeri fm, marcora sm, coutts aj. internal and external training load: 15 years on. int j sports physiol perform 2019;14(2):270-273. [doi: 10.1123/ijspp.2018-0935] [pmid: 30614348] 6. west sw, williams s, kemp sp, et al. athlete monitoring in rugby union: is heterogeneity in data capture holding us back? sports(basel) 2019; 7(5): 98. [doi: 10.3390/sports7050098] [pmid: 31035621] 7. west sw, williams s, kemp spt, et al. patterns of training volume and injury risk in elite rugby union: an analysis of 1.5 million hours of training exposure over eleven seasons. j sports sci 2019; 38(3): 238-247. [doi: 10.1080/02640414.2019.1692415] [pmid:31755824] 8. kelly dm, strudwick aj, atkinson g, et al. quantification of training and match-load distribution across a season in elite english premier league soccer players. sci med football. 2020;4(1):59-67. [doi: 10.1080/24733938.2019.1651934] 9. bradley wj, cavanagh b, douglas w, et al. energy intake and expenditure assessed 'in-season' in elite european rugby union squad. eur j sports sci 2015;15(6):469-479. [doi: 10.1080/17461391.2015.1042528] [pmid: 26055695] 10. rago v, rebelo a, krustrup p, et al. contextual variables and training load throughout a competitive period in a top-level male soccer team. j strength cond res 2019. [.doi: 10.1519/jsc.0000000000003258][pmid: 31453936] 11. mckay cd, cross m, kemp s, et al. strategies used by professional rugby union clubs to manage players for artificial turf exposure. s afr j sports med 2020;32(1):1-7. [doi: 10.17159/2078-516x/2020/v32i1a8276] 12. foster c, florhaug ja, franklin j, et al. a new approach to monitoring exercise training. j strength cond res 2001;15(1):109115. [doi: 10.1519/00124278-200102000-00019] [pmid: 117086927] 13. hinkle de, wiersmaw, jurs sg. applied statistics for the behavioural sciences. 5th ed. boston: houghton mifflin; 2002. 14. bates d, maechler m, bolker b, et al. package "lme4". in: bolker b, editor. cran; 2018. (please check this reference – there is something incorrect in the way you have set it out. please also provide a web reference showing source.) 15. lenth rv, buerkner p, herve m, et al. cran – package emeans (r-project.org) estimated marginal means, aka least-squares means. 2021 [cited; available from: https://cran.rproject.org/web/packages/emmeans/index.html] 16. cohen j. statistical power analysis for the behavioural sciences. 2nd ed. new york: routledge 1988. pp. 284-287. [doi: 10.4324/9980203771587] available at: https://www.taylorfrancis.com/books/mono/10.4324/9780203771 587/statistical-power-analysis-behavioral-sciences-jacob-cohen 17. roberts sp, trewartha g, higgitt rj, et al. the physical demands of elite english rugby union. j sports sci 2008;26(8):825-833. [doi: 10.1080/02640410801942122] [pmid: 18569548] file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.%20%201249/ file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1136/bjsports-2016-096581 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:10.1177/1747954116637153 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:10.1177/1747954116637153 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1055/a-1268-8791 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1055/a-1268-8791 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1123/ijspp.2018-0935 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.3390/sports7050098 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1080/02640414.2019.1692415 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/%5bdoi:%2010.1080/24733938.2019.1651934 doi:%2010.1080/17461391.2015.1042528 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/.doi:%2010.1519/jsc.0000000000003258 doi:%2010.17159/2078-516x/2020/v32i1a8276 doi:%2010.17159/2078-516x/2020/v32i1a8276 doi:%2010.1519/00124278-200102000-00019 https://cran.r-project.org/web/packages/emmeans/index.html https://cran.r-project.org/web/packages/emmeans/index.html doi:%2010.1080/02640410801942122 doi:%2010.1080/02640410801942122 sajsm 595 (commentarty).indd commentary 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license changing player behaviour in sport during the covid-19 pandemic: shake on it? j mckenna,1 phd; s h backhouse,1 phd; g phillips,2,3 mbchb; b jones,1,2,4,5,6 phd 1 carnegie applied rugby research (carr) centre, carnegie school of sport, leeds beckett university, leeds, uk 2 england performance unit, the rugby football league, leeds, uk 3 hull kingston rovers, hull, uk 4 leeds rhinos rugby league club, leeds, uk 5 division of exercise science and sports medicine, department of human biology, faculty of health sciences, the university of cape town and the sports science institute of south africa, cape town, south africa 6 school of science and technology, university of new england, armidale, nsw, australia. corresponding author: b jones (b.jones@leedsbeckett.ac.uk) following the return to professional sports, it must be noted that risks remain. regardless of the sport, managing the transmission of sars-cov-2 is challenging. unlike national basketball association (nba) players, who completed their 2020 championship under quarantine in disneyland, athletes and club officials from most sports come to training and competition from local communities with distinctive risk profiles. these athletes are required to follow government and national governing body (ngb) guidelines, while attempting to compete as normal. in rugby league, despite the introduction of rule changes and risk mitigation strategies,[1] covid-19 outbreaks have occurred.[2] what is the best way to go about planning the successful management of covid-19 transmission through scheduled behaviour change? as behaviour is key to preventing infection and improving outcomes, its management is crucial.[3] with covid-19, many behaviours and effective actions should be guided by behavioural science frameworks. one such framework, the capability, opportunity and motivation-behaviour (com-b) model,[4] recognises that behaviour (b) emerges from the interaction between an individual’s capability (c), opportunity (o), and motivation (m) for engaging in a specific behaviour. this model provides a guide for what needs adjustment for an effective behaviour change intervention. this model has been used within elite level sport to further understand the adherence to nutritional guidelines[5] and help rugby league players achieve performance goals.[6] a popular aphorism holds that 100% is easier than 98%. sarscov-2 transmission thrives in groups where too many people live at the 98% level. this underlines the importance of designing systems and processes that reflect how players and coaches prefer to close that 2% gap. while simply accepting the 2% gap seems irrational, it is often predictable.[7] for example, it may seem irrational for drivers to routinely turn down the radio to either reverse or to look for specific road signs. yet without realising why, drivers do reduce the sound distraction as this helps to manage the momentary, easily overlooked but potentially lethal costs associated with loss of attention or attention-switching. in rugby league, one challenge within the specific match day context is the post-match handshake or hug, which is a nonessential player-to-player interaction. [1] in this current scenario, it is likely that the personalities associated with the playing context are different to those of training. this puts a new and powerful meaning to the idea of game face, namely, it alters players’ responsiveness to what works on non-match days. indeed, as evidence of their conscientiousness, players may have made substantial investments in refining the routines they believe work and may be resistant to change. they will need support to change because many are likely to feel that change will activate the worries of the neurotic tendencies that may accompany their game face. match days represent micro-moments (opportunity) when all the benefits arising from self-regulation (capability) and defaults (motivation) of non-match days, can lose their influence. emphasising the com of match days may help to take the 2% out of the rugby league system, with examples illustrated in fig. 1. focusing on post-match handshaking and hugging, new postmatch routines at the final whistle will be important to embed the new practices into the sport’ new normal. developing a nd practicing fun, easy and new ways to show respect for opponents and for the game itself, may enhance players’ motivation for change. a complementary approach based on opportunity could change the defaults so that teams enter and leave the pitch individually rather than side by side. this contrasts with existing behaviour for example, at the final whistle, after a hard-fought match, the close proximity of the players may represent an automatic and unhelpful trigger for ubiquitous and habitual handshaking and hugs. to enhance motivation, new rewards and incentives may need to be considered for teams upholding the new defaults. of course, all this presupposes that infection rates arise within the context of player-to-player contact. another complexity lies in how to prevent the virus from entering clubs. to prevent the spread of infection during matches and training activities is a major challenge facing all sports returning from the enforced covid-19 shutdown. during training and matches, rugby league players make contact with others which can result in sars-cov-2 virus transmission. while these interactions characterise the appeal of the game, a number of them can be avoided, including shaking hands and conversing after the match. this paper presents a framework underpinned by behavioural science (capability, opportunity, motivation and behaviour model, com-b) to support stakeholders in helping players adopt new social distance norms and behaviours. this framework helps to ensure the players have the capability, opportunity, and motivation to adopt new covid-19 risk minimising behaviours, which they will need to commit to 100%. keywords: rugby, virus illness s afr j sports med 2020; 32:1-2. doi: 10.17159/2078-516x/2020/v32i1a8967 mailto:b.jones@leedsbeckett.ac.uk http://dx.doi.org/10.17159/2078-516x/2020/v32i1a8967 https://orcid.org/0000-0002-4810-5173 https://orcid.org/0000-0001-6779-3939 https://orcid.org/0000-0003-0947-0677 https://orcid.org/0000-0002-4274-6236 commentary sajsm vol. 32 no. 1 2020 2 herein lies part of the explanation for the nba adopting a ‘closed camp’ approach. their quarantine approach, beyond the 113-page rule book distributed to players before the season resumed, activated the power of physical opportunity via environmental restructuring i.e. they used default effects to minimise the risk of the 2% occurring. at the completion of the 2020 nba championships, in quarantine no positive covid-19 tests were recorded, while one player lost his contract for breaking quarantine rules. for the nba, their new default meant that all concerned accepted strict accountability, which is all about motivation. no one was allowed the luxury of debating or challenging their personal and collective accountability because this closes that all important 2% gap. for rugby league and other sports not in disneyland, providing alternative safe practices that players and staff can enact through focussing on their capability, opportunity and motivation, is critical for supporting effective behaviour change that will limit the potential for high risk sars-cov-2 transmission situations. conflicts of interest and source of funding: bj and gp are employed by the rugby football league in a consultancy capacity, although this is not seen as a competing interest. the authors declare no sources of funding. acknowledgements: the authors would like to acknowledge the input of dr sergio lara-bercial, kacy mackreth and dr sarah whitehead for comments on the initial content. references 1. jones b, phillips g, kemp s, et al. a team sport risk exposure framework to support the return to sport. available at: blogs.bmj.com/bjsm/2020/07/01/a-team-sport-risk-exposureframework-to-support-the-return-to-sport/accessed 9 september 2020. 2. hull fc: 12 covid-19 positive tests among players and staff at super league club. available at: bbc.co.uk/sport/rugbyleague/53791886 accessed 9 september 2020. 3. chater a, arden m, armitage c, et al. behavioural science and disease prevention: psychological guidance. available at: uobrep.openrepository.com/handlet/10547/623940 4. michie s, van stralen mm, west r. the behaviour change wheel: a new method for characterising and designing behaviour change interventions. implement sci 2011; 6: 42. [doi.org/10.1186/1748-5908-6-42][pmid: 21513547] 5. bentley mr, mitchell n, backhouse sh. sports nutrition interventions: a systematic review of behavioural strategies used to promote dietary behaviour change in athletes. appetite 2020; 150: 104645. [doi.org/10.1016/j.appet.2020. 104645] [pmid: 32112958] 6. costello n, mckenna j, sutton l, et al. using contemporary behavior change science to design and implement an effective nutritional intervention within professional rugby league. int j sport nutr exerc metab 2018; 28(5): 553–557. [doi.org/10.1123/ijsnem.2017-0298][pmid: 29345174] 7. ariely d. predictably irrational, revised and expanded edition: the hidden forces that shape our decisions. revised and expanded ed. edition. new york, ny: harper perennial, 2010. fig. 1. addressing the capability, opportunity and motivation of rugby league players and support personnel to influence covid-19 positive behaviours, adapted from michie et al. [4] http://dx.doi.org/10.1123/ijsnem.2017-0298 sports medicine sportgeneeskunde jo u r n a l o f th e s.a. sports m edicine association tydskr1f van die s.a. sportgeneeskunde-veren1ginc. september 1989 volume 4/number 1 injuries in first-class c ricketan analysis c atastrophic rugby injuries psychological factors in sports injuries r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) new ybltanen emulgel. llie unique gel/cream combination r to beat pain and inflammation, w ^ s o o t h i n g e m u l s i o n c r e u m f o r t h e p e n e t r a t i v e effect o f r u b b i n g i n . .. • "emulgel keeps you in action. it is the ideal anti-inflammatory treatment for the relief o f localised inflammation and pain in sports injuries due to sprains, strains and bruises. • 'e m u lg e l’s unique combination of cream and gel allows for the penetrative effect of rubbing in, while the gel forms a layer to al persistent penetration. • "emulgel’s deep-penetrating action confines itself to the local problem, giving relief, with minimum likelihood of side-effects. • ‘ emulgel provides on-the-spot, convenient medication. • from ciba-geigy. leaders in transdermal therapy. c o o l i n g g e l f o r m s ;t l a y e r f o r g r a d u a l p e n e t r a t i o n v oo aren e r n it e e l u t t r a m a n !>fcp hena: dejbytorrrrxxirn l.tog/ioog v o lla n e n e m u l g e l beat the paiagothe distance. n o w a v a i l a b l e a t y o u r p h a r m a c y w i t h o u t p r e s c r i p t i o n . c ib a -g e ig y d'clophenac diethylammonium 1,16 a/100 g r 3 g . n 0 . u / 3 .1 / 7 7 \aal <sfnach r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) c o n t e n t s t y d s k r if v a n d ie s.a.jo u r n a l o f th e s.a. sports medicin e / sportgeneeskunde a s s o c ia t io n v e r e n ig in g v o l u m e 4 n u m b e r 1 s e p t e m b e r 1989 e d ito r in c h ie f: d r c n o b le a/i 8 b c ii, f c s (s a ) a s s o c ia te e d ito rs: p r o f t n on kes. m b c lib .m d d r d mi'ie van v eh len m b cub (s lc ll) m prnx m ed (p re to ria ) a d v is o r y b o a rd : m edicine: d r i cohen m b chb d.obst rcog o r th o p a e d ic tra u m a to lo g y : d r p f irer b s e (e n g )m b b c h ( w i ls ) m m e d (o r th o ) < w its) b rig e h u g o m b c h b , m m e d (c h ir ) ■ o rth o p a e d ics: d r 1c lifttin m b b c h , f r c s (e d in ) c a rd io lo g y : c ol d p m y b u r g h s m m b c lib f a c c p h ysical e d u ca tio n : p r o f h a n n es b o th a d phil (p ln/s ed) g y n a e co lo g y : d r la c k a d n o m b bcii ( w its) m d (m ed ) d ip o & g (w its) c o n t en t s e d itorial co m m e n t n e c k injuries in r u g b y ................................................. 2 s a s m a n ew s n e w s a s m a l o g o ......................................................... 3 c rick e t in ju ries injuries to sou th afr ic an c ricke ter s p laying at firs t-c lass l e v e l ....................................... 4 f isio lo g ie die fisi ologi es e v o o r d e le van o p w a r m i n g en a f k o e l i n g ........................................... 6 f a rm a k o lo g ie m id d e l s in s p o r t .............................................................. 9 n ew p ro d u ct v o lt a r en su p p o s it o r ie s 1 2 , 5 m g ................................ 10 r u g b y in ju ries c a ta s tr o p h ic injuries o f the sp in al c o r d ......................................................................... 11 p sy ch o lo g y p sy ch olo gica l fa ctors and sp ort s i n j u r i e s ........... 13 letters to the e d ito r........................................................ ...........16 d iet t h e ath le te and his diet in g e n e r a l ................... ...........17 u ltram an r o u n d u p 1 9 8 9 .............................................. 18 m a f r i c a n s p o r t s m e d i c i n e p ictu re s c o u rte s y of p h oto file/im age b ank sasgv sasma p u b l is h e d b y t l ie so u a ss o c ia t io n h a i'f i el d ko r u m w e st hv>7 a r c a d ia st r e f t h a t f ie l d p r e t o r ia , 0 0 8 3 t h e jo u rn a l oi t h e s a s p o r ts m e d ic in e a s s o c ia tio n »s e x c lu s iv e ly sp o n s o re d b y c ib a g e ig y (p ly ) l td. t h e jo u r n a l )> p ro d u c e d b v c o m m e d ic n , p o box 3 9 0 9 , r a n d b u rg , 2 1 2 5 .t h e vie w s e x p re s s e d in th is p u b lica tio n a re th o s e o t the a u th o rs an d not n e c e s sa rily th os e o f th e s p o n s o r s o r p u b lish ers ctsa m • <r s p o r t g e n e e s k u n d e v o l 4. n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports medicine editorial n eck in juries in rug by r u g b y has b ee n des cribed as a co llis ion sport, and as su ch inju rie s ar e inevitable. w h e n se r io us injuries o cc u r fre qu en tly th e n o n e has to look to ch a n g in g the rules to d im in is h the incidence o f these injuries. n e ck inju ries b e c a u s e of their p o ­ tentially ca ta s tr o p h ic co n s e q u e n c e s h a v e been featured p ro m in en tl y in the m edica l an d lay litera­ ture. t h e in te rn at iona l r u g b y b o a rd , th r ou gh their m edica l c o m m i tt e e h a v e been act iv e in this regard. t h e y ha ve penalis ed the high tackle and ha ve tried to tight en up on the s c r u m m i n g rules. u n fo rt u n a te ly this so far has not resulted in a re du ct io n in ser ious nec k injuries. prof.a.t. s c h e r 's statistics fro m the c a p e area h a v e revealed an inc re as ed in cid e n ce of neck injuries largely in sc ho ol boys. t h is m e a n s that at sc h o o lb o y level the n ew laws are not a d e q u a te or ar e not b ei n g en fo rc ed properly. in the s c ru m the forc es on the a d o le s ce n t n ec k are too gre at es p ec ia ll y w h e n the s c r u m co llaps es. it is therefo re im p era tiv e to re d u ce the forc es in the sc ru m and the d a n g e r of the s c r u m c ollap si ng . a n u m b e r of so lu ti o n s h a v e bee n su gg es ted b ut m a n y o f these are h ig h ly technical such as the re lationsh ip of the hips to the s h o u ld e r s an d the d e g r e e of w h e e li n g of the scrum. su re ly a r e du ct ion in th e n u m b e r o f playe rs s c r u m m i n g at sc ho ol level is the an sw er . r e d u c in g the p u sh in g for w a rd s to three or m a x im u m five, will a ch iev e both be tter stability in the s c r u m and r e d u ce the forces in the scrum. if 5 m en ar e used , the se co n d row of for w a rd s sho uld be in the flan k and not the lock p ositio n w h ic h will fu r­ ther add to the stability. o n c e m a turi ty is reached the eigh t m a n s c ru m can ag ain be used. as re ga rd s the high tackle, the law s sh oul d be better en fo rc e d and bet te r tackl ing te ch n iq ue s sh oul d be taught . n e c k s tre n g th e n i n g exe rc is es sh oul d be c o m ­ pu lso ry at all s c ho o ls w h e r e ru gb y is played. f in ally a re gis ter of neck inju rie s sh oul d be kept in sou th afr ic a and the statistics m a d e pu blic at the end o f each se as on . l e t 's m a k e r u g b y s a f e r — p le a s e ! dr. c liv e n o b le m b b c h , f c s (sa) e d it o r -in -c h ie f sam sa new s / sasg v nuus it is w ith g re a t p le a su re that w e can a n n o u n ce that w e are n ow in a p osition w h ere w e can co n tin u e to p u b lish o u r jo u rn a l, b rin g in g you m an y in te re stin g and in fo rm a tiv e a rticles. h o w e v e r, due to the h e a v y fin a n cia l co m m it­ m en t to p u b lish a jo u rn a l of this fo rm a t, w e w ill in the fu tu re h ave to sen d the jo u rn a l o n ly to su b scrib e rs and m e m b e rs of the s a m s a at a sm all fee. d e ta ils w ill be an n o u n ce d sh o rtly . d ie sa s p o rtg e n e e sk u n d ig e v e re n ig in g h et h om o ok b e y w e ro m 'n o o rs p ro n k lik e w ap en te o n tw e rp en u sien die resu lta te van die g o e d g e k e u rd e em b le e m reed s in h ie rd ie u itg aw e. h ierd ie em b leem is h e ra ld ie s b eter o n tw e rp as die v o rig e een en lui sp re e k w o o rd e lik 'n n u w e era in v ir o n s v e re n ig in g . o n s h oop om ons d ie n ste aan ons led e nog v e rd e r u it te b rei en o n tv a n g g ra a g v o o rste lle of k ritie k in h ie rd ie v e rb a n d . d a a r w ord re e d s b ep lan v ir 'n s p o rtg e n e e s k u n d ig e o p le id in g sk u r su s ty d en s 27-29 ju n ie 1 9 9 0 in p ort e lizab eth . n e w s a m s a l o g o t h e h a n d so m e n ew s a m s a logo a p ­ p ears fo r the first tim e in this issue of s p o rts m e d icin e . m e m b e rs w ill su rely a g ree that it m eets all the crite ria of a w e ll-d e sig n e d logo: it is a d y n a m ic g ra p h ic, w ith a high level of e n erg y as b efits the top ic it is to co n v ey . the m e d ica l a sp e ct in te g ra te s co m fo rta b ly in the d e sig n so that all in all w e h ave a m o d e rn d esig n that w e can live and g ro w w ith in the years to co m e. d r. d a w ie van v eld en m b , c h b , m .p rax. s a s g v s a s m a s p o r t s m e d ic in e . v o l 4. n o 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket injuries injuries to south african cricketers playing at first-class level r ic h a r d a s t r e t c h : d e p a r t m e n t o f h u m a n m o v e m e n t st u d ie s , u n i v e r s i t y o f f o r t h a r e a b s t r a c t kei/worils: in ju rie s , cricket t h e p u rp ose o f this in v e stig a tio n w as to d e te rm in e the m ost co m m o n crick e t in ju ries and to m ak e re c o m m e n d a tio n s in an a tte m p t to red u ce the n u m b e r of in ju ries. t h e su rv ey p o p u la tio n co n sisted of 92 p lay ers w ho had p lay ed first class crick et d u rin g the 1 9 8 7 /8 8 seaso n . o ne h u n d re d and n in e ty -th re e se rio u s and 73 less se rio u s crick et in ju ries, w hich had o ccu rred th ro u g h o u t these p lay ers' ca re e rs, w ere re co rd e d . t w e n ty p ercen t o f the se rio u s in ju ries w ere to the h ead , n eck and face, 32% to the u p p e r lim b s, 18% to the b ack and tru n k , and 30% to the lo w er lim b s. t h e in ju ries w ere p rim arily im p act in ju rie s as a resu lt of b ein g h it by the ball e ith e r w h ile b attin g o r fie ld in g , stress in ju ries as a resu lt of rep e titiv e m o v e m e n ts fo r a p ro lo n g e d len g th of tim e, and m u scle and lig a m e n t in ju rie s n o rm ally asso ciated w ith field sp o rts. r e co m m e n d a tio n s re g a rd in g the use of e q u ip m e n t, tra in in g and p ra ctisin g for crick e t w ere m ade in an a tte m p t to red u ce the risk of in ju ries. in t r o d u c t io n ese ar ch into cricket, a c o n ­ s e r v a t i v e a n d t r a d i t i o n a l sport, has been neglected. h o w ev e r, the s o u th african c r ic ke t un ion and the form scaffc rick et c oach in g acad ­ emy have recently established a cricket research centre. this resea rch cen tr e will no d o ub t co n tri b u te to the e v o l u ­ tion of cricket from a traditional art to a blend of art and science. th e introduction of vast s u m s of money, m o re fixtures, esp ec ially lim it ed -over s m atches, and the in creas e in the n u m ­ ber of fast b o w le r s on pi tches pre ­ pared for them, has placed ad ditional stresse s and strains on the m o d ern cricketer. besides sound technical skills, these cric ke ters need to po ss ess a high a u t h o r ' s a d d r e s s : r . a . s t r e t c h 1 0 3 q u e e n s r o a d k i n g w i l l i a m ' s t o w n 5 6 0 0 a ck n o w l e d g e m e n t s : t he a u t h o r w o u l d like to a c k n o w le d g e the as si st a nc e received from the r e s e a r c h d e p a r t m e n t o f the f o r m s c a f f c r i c k e t c o a c h i n g a c a d e m y f o r this project. level of fitness thus m a k in g them s u s ­ cept ible to the traditional direct inj u­ ries of being st ruck by the ball, indirect in ju ri es su ch as m u s cle tears and r u p t u r e s , a n d o v er -u se injuries as a result of re­ p e titiv e t r a in in g for a sp o rt that is bec om ing more ex­ plosive in nature. injuries to first class cric ke ters in a u s ­ tralia w as found to b e 1 per 30 ma n ho urs played. ’ a si gn ifi ca nt increase th e british sport c o u n c i l 12 s u r ­ veyed 213 te am s in n o r th er n e n g ­ land an d recorded 251 in ju riesd uri n g a season. th e y estimated the risk of injuries to the cr ic ke t pl ayers to be 2,6 per 10 000 m an hours played. h o w e v e r , th e s e fig ures exc lu ded injuries th ough t to be trivial, as well as m a n y ch ron ic ov eru s e injuries. t h e rate of all s p o r t c e n e e s k u n d e v o l 4. n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket injuries in o v er -u s e injuries in y o u n g children, esp ec ially in the ar eas o f stress frac­ tures and g ro w th car tilage injuries was found. a c c o r d in g to these a u th o rs the p ri m a ry areas of co n c ern , particularly to the y ou n g fast b o w le rs , is d a m a g e to the g ro w th car tilage o f the k ne e and traction ap o p h y s is , as well as c o m ­ p re ss iv e stress to the artic ul ar su rface cartilag e of the f e m u r a n d talus. t w e n t y f iv e pe rce nt of injuries o ccur to the head , face and nec k with c o n t u ­ sions, lacerations and nose bleeds being the m o st co m m o n . : se v en cases of c o n c us s io n w er e repo rte d in players w h o were st ruck by the ball. eye injuries in cr ic ke t w ere reported as long a g o as the b e g in n in g of the c e n tu r y .4 t w o , out of a total o f fifteen, cas es o f ocu lar injuries were reported to h a v e been cau se d by cricket balls. d a m b r a i n 5 repo rte d two cases of c h r o n i c g la u c o m a seco n d ar y to trauma, out of a total of 18 as so ciate d with cricket, w hile 4% o f 184 cases and sev en p erc en t of 65 cas es o f o cu la r c o n c u s ­ sion injuries in s p o r t s m e n w e re re ­ po rted o f five cas es of eye injuries repo rte d, four resulted w hile batting. o f these b atting injuries, three w er e as a result of the ball def le ct in g off the top ed g e o f the bat w hile hoo kin g and strik ing the ey e on the side of the d o m in a n t hand. fin g er s w er e found to be the most v u ln er a b le site for inju­ ries th e s e inju rie s consi sted pri­ m a ri ly o f fractures , dislo ca tions and con tusi on s su stai ne d whil e batting and fielding. t h e d a n g e r of a fracture, as a r e s u l t o f being struc k by the ball, to the distal third of the uln a r of the top hand w h e n batting w as also indicat ed, but no cases of this inju ry w er e reported " t h r o w e r 's s h o u l d e r " w h ic h is caused by d eg en e r a ti o n and in fla m m a to ry ch a n g es or partial an d c o m p le te ru p­ tures of the rotator cuff, usually m uscl e of the bi ce p s ten don, is rega rd ed as a c o m m o n cricket in ju ry .11’ t h e case of a y ou n g fast b o w le r w ho dev e lo pe d acu te p n e u m o m e d i a s ti n u m and bilateral p n e u m o th o r a c e s whil e practising fast b o w li n g was r e p o r t e d 1', w h il e sp o n d y lo ly s is w as found to be co m m o n in a u stra lia n fast b o w le r s p l a y i n g first class c r i c k e t t h i s injury is d u e to a stress fracture that occ ur s to the parts inter ar ti cu la n s on the side o pp o si te the bo w li n g a rm as a re sult of the ro tat ion an d ex te nsi on of the back w h e n b o w li n g fast. pain occ ur s in the lo w er lu m b a r region or is localized in o n e side of the spine, s o m e t im e s r a d i­ ating to the b u tt o c ks or leg after c o n ­ tinuo us stress to the back. se riou s injuries, m a inly to the lo w er b ack of a n u m b e r of elite and ju n io r fast b o w le rs w e re found l2. c or r ig a n c' reported that m u s cle tears of the a b d o m e n o c ­ cu rr ed in fast bow lers, w hile b a ts m en suffered rib fractures and soft tissue injuries, esp ec ially to the u p p e r leg, a b d o m e n and testicles. m a n y injuries o cc ur in the low er limbs d u e to im p ac t from the ball, stress inju rie s a s s o cia te d w it h re p et it iv e m o v em e n ts and other injuries normally asso ciate d with field sports. t w en ty five percent of injuries o cc u r to the lo w er limbs with the m ajo rity being s trains and sprains. fast b o w le rs are particularly likely to suffer from muscle tears, especiall y o f the hip flexor, the a d d u c to r lo n g us o f the leg and the re ctus fem ori s m u s cles c' ui. c o r r ig a n c| is of the con ten ti o n that stress fr ac ­ tures are c o m m o n in fast b o w le r s and occ ur primarily in the metatar sal bones, the fibula and tibia. f u rth erm o r e talotibial ex osto ses, p at el la r te n d o n i­ tis, bruised heels and 'shin splints' o cc u r as a result o f o v eru s e an d are m o r e c o m m o n to w a r d s the en d of the s ea s on l). t h e pu rp ose of this in v estig at ion was to d e t e rm in e the m ost c o m m o n cr ic ke t injuries and to m a k e r e co m m e n d a t io n s in an a tt em p t to r e d u ce the risk of injury. m e t h o d s postal qu es tio n n a ir e s w er e se n t to 154 cric ke ters w h o had played in the 198 7 / 8 8 c u r r ie c u p an d cas tle bowl co m p et it io n s. n i n ety -tw o q u e s t io n ­ n a ir e s (6 0 % ) w e r e r e tu r n e d . t h e injuries re co rd ed w er e not restricted to th ose received d ur ing that season, but w e r e all the injuries r ece iv ed while p la yin g cl ub an d pr o v in ci al cricket. f or the p u rp o se of this su rv ey injuries w ere g ro upe d a cc o rd in g to two c lassi­ fications. t h e less ser ious inju rie s were those that did not p re v en t the player from practising or training for the game, w hile the ser io us inju rie s w er e those that pr event ed the p la ye r from pra c­ tising or training for a d ay or more. t h e injuries w er e furth er d iv id ed into injuries in four regions of the body: the head, neck and face; the u p p er limbs; the ba ck and trunk; and the lo w e r limbs. t h e sa m p l e statistical a n a l y s i s sy s te m (sas) w as used to co m p u te the data and to p e rfo r m cross tabulat ion s. t h e sm al l s a m p le size did not a llo w for furt her statistical an alysis. r e s u l t s n i n e t e e n of the cric ke ters in this in v es­ tigation had pl ayed cricket at in tern a ­ tional level, w hile the highest level the o ther 73 pl ay ers had p la ye d at was provi nci al level. t h e y had a m e a n age o f 27,0 years, a n d a m e a n bo d y m as s of 82 kg and a m e a n statur e of 1,82 meters. t h e s e val ues w ere si m ila r to tho se m e a s u re d in an a n th r o p o m e tr ic st u d y on south af ric an first-class cr ic k ­ eters l3. t h e r e s p o n d e n ts co nsiste d of 31 b a ts ­ m e n , 36 a ll -r oun der s, 16 b o w le r s and nine w ic ke tke ep ers . d u ri n g the off­ s ea s on 30% o f the re s p o n d e n ts spent no ti m ep ra ct isin g or training forcricket, w hile 47% s pe nt b etw ee n o n e and four hours per w ee k training and p ra ctis­ ing for the va ri ou s a spects of the gam e. d uri n g the p re -s easo n period, 70% of the r e s p o n d e n ts s pe nt b e t w e e n three a n d eight hours a w ee k pra cti si n g and training specifi cal ly for cricket. d ur­ ing the s ea s on , 50 % of the re sp o n de n ts sp en t b etw ee n se v en and ten hours per w ee k prac tising and training for cric ket, w hile a furt her 27% sp e n t more than ten hours per w ee k practising and training. s p o r t s m e d ic in e . v o l 4. n o 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket injuries o n e hundre d an d nin ety -t h re e serious a n d 73 less ser ious cricket inju rie s w ere recorded. o f the se r ious inju rie s 20% were to the head, 32% to the u pp er limbs, 18% to the b a c k an d tr un k and 30% to the low er limbs. s e v en ty -fo u r percent of these injuries occurred during matches, 21 % d urin g practices and 5% occ urred d ur ing b o th m a t ch e s and practices. f o r ty -tw o perc en t of the ser ious injuries o ccurred w h il e b a t­ ting, 33% whil e b o w li n g, 19%. while fielding and 5% w h il e either w a r m in g up or training. o f the less serious injuries 16% w ere to the head , 43% to the u p p er limbs, 14% to the b a c k and trunk and 27% to the low er limbs. h ea d n e c k a n d f a c ia l in ju r ie s o f the 38 head injuries s u s ­ tained, 66% occ urred while the b a ts m en w ere w e a r ­ ing no h el m et and 24% while the b a ts m en were w ea ri n g hel mets with v' su st ainin g 24 injuries. n i n e t e e n in ju ­ ries w er e su stai ne d w hile c a tch in g or fielding the ball and one w hile w a r m ­ ing up for a match. t h e s e results su p p o rt the fin dings of o ther re s ea rc h ers w h o found that fin­ g er injuries were the m ost c o m m o n cr ic ke t in ju r ie s .izv) b a c k a n d t r u n k in ­ ju r ie s t w e n t y f i v e (7 1 % ) e a r p i e c e s o n l y . t h ir ty -o n e (81%) of the hea d in ju ries were as a result of either being struck by the ball w hile a tt e m p tin g to hook, by the ball deflecting off the top edge of the bat on to the head w hile pl ayi ng a horizontal bat stroke, or as a result of being struc k by the ball rearing off the pitch. th e s e head injuries su staine d while batting inclu ded tw o c o n c u s ­ sions, eight br o k en nose an d ch eek bo ne s, and 21 lacerations, re qui ring stitches, ar oun d the eyes, m o u t h an d chin. t h e top and m iddle o rd er b a ts m en su st ai ned m o re im p ac t injuries to the he ad (24) than the low er ord er b a ts m e n (11). u p p e r lim b in ju r ie s o f the 62 u pp er li m b injuries nine cases of sh o uld er injuries w ere recorded w'ith four of these su staine d w h il e b o w li n g and five w h il efie ld in g . t h e pha la nge s, metacarpal and lower arm injuries made up 50 (81%) of the u p per li m b injuries. t hir ty of these w ere ca u s ed while ba tting with the top and m id d le ord er o f v t h e 3 5 b ac k an d trunk injuries w ere to the lo w e r and m i d d l e back. t h e s e w er e m a inly m usc le , li ga­ m e nt and te n d on injuries. t w e n t y three of these were su st ain ed whil e b o w li n g or as a result of the repetitive m o v e m e n t s of bo w li n g m a n y overs. l o w e r l im b in ju r ie s t h e 5 8 lo w er lim b injuries c o n si st e d of injuries to the b ones of the foot (11), a n kl e lig a m en t (11), m u s cles of the lo w er leg ( 5 ) , knee car tilage (6), q u a d ­ riceps an d h a m s tr in g m u s cles (10) and the groin (13). t w e n t y tw o (38%) low er lim b injuries w ere either as a result of c o n tin u a l b o w li n g or ca u s ed by b o w l ­ ers tr a m p in g in the ro ugh foot m a rk s on the pitch in their deliv e ry stride and fol low through. t en (17%) lo w er limb inju rie s su sta ined w er e m u sc le and li gam en t injuries ca u se d whil e b a ts m e n w ere r u nning b etw ee n the wickets. l ess s e r io u s in ju r ie s t h e less se rio us injuries co n si st ed of 30 (41 %) im pact injuries, 21 (29)% stress injuries from re peated actions and 22 (30%) injuries norm ally associated with field sports. t h e im p ac t injuries were as a result of b ein g st ruck by the ball on the hand and for ea rm ( 1 9 ) , head (10) and foot (1) t h e o ther injuries were m a inly m u sc le and li gam en t strains to the neck, bac k and trunk ( 1 3 ) , s h o u l d e r and elbow, (11) gro in (4) and ham st rin g (8) and three m ino r cases of shin splints. d is c u s s io n t h e top o rd er b a ts m en face the fast b o w le rs at the b eg in n in g of the innin gs w hen the b o w le rs are rested. d u rin g the early part o f the inni ngs the ball an d w icket possess m o r e b o u n c e and tend to fa v ou r the bo w le rs m a k in g the b a ts m e n m ore su sc ep ti b le to im pa ct injuries, e s p e ­ cially to the head , h a n d s and forearms. specialist b o w le r s w er e found to s u s ­ tain m o r e hand injuries w hile batting, than the specialist ba tsmen even though the y spent less time batting \ th ey co n ten d ed that the b o w le rs w er e not as skilled at b atting and did not p o s ­ sess the reactions and te ch n iq ue re­ qu ired to deal with fast b ow lin g. o n e factor that m ay ha ve resulted in the d if fer ence in these fin dings is that the a u stra lian pi tches are traditio nally faster and m o r e b o u n c y than those in s o u th africa thus m a k in g it m o r e d if ­ ficult for the less skilled b a ts m en to play fast b ow lin g. t h e ability to ru n with the pads on and the skill o f r u n n in g b etw ee n the w ic k ­ ets is not oft en practised by cr icketers. m o r e atten tion sh oul d be placed on this as pe ct, by inc lu ding it as part of the fitness train ing , in an a tt em p t to el im in a te a n y u nn e ce ss a ry injuries su stai ne d w hile r u n n in g betw ee n the w ickets. at front-foot im pa ct , the fast b o w le r 's (c on tin u ed on p ag e 19 . . . ) s p o r t c e n e e s k u n d e v o l 4. n r 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) fisiologie die fisiologiese voordele verbonde aan opwarming en afkoeling dr p e k ruger in l e id in g indien ons v a n d a g 'n g es p re k sal voer o o r d ie b e g i n s e l s v an o e f e n p r o g ra m v o ors kri ft e, sal alle afrigters met g esag d a a r o o r kan praat en kan getuig dat hulle o e f e n p r o g r a m m e een of meer van hierdie b eg in se ls insluit. wa n n eer ons eg te r o o r o p w a r m in g en fle ksitei tso efe ning praat, d an sal die m e es te van ons er ken dat hierdie ged ee lte van ons v o o r b ere id in g nie sy r e gm a tig ep lek in ons o efen p r og ra m m e en v o o rb er e id in g s fa s es in n e em nie. da ar word slegs 'n pa a r m in n te vo or en mi skein na die oef en in g, d us die a fsk eep tyd jie s,aa n hierdie gedeelte van o n s in oefe ning b estee terwyl dit in werklikh eid 'n integrate dee l van ons v o o rb ere id in g m o et u itm aa k. laat ons dan nou baie v lu gtig kyk na wat die v o o r d e l e v a n o p w a r m i n g en fle ksi te it so efe n in g e is en ho e dit kan bydr a tot v er b eterd e prestasie. f u n k s ie s v a n o p w a r m in g 1 v e r b e t e r d e p r e s t a s ie in d ie rustende liggaam is die blo ed vloei na die spiere relatief laag as g ev olg van die va so ko nstrik tiew e toestand van die klein bloedva te . so o s wat die in tensiteitvan 'n a k ti w it e it v er h o o g word, p e k ruger d ep artem ent m enslike b ew eg in g sk u n d e, u n iversiteit van pretoria so v a so d il a te er die b lo e d v a te en m e er bloe d vloei na die spiere. t y d e n s rus vloei 15-20% van die k ard iale uitset (q) na die spiere. t y d e n s oef en in g van 10-12 m in u te v e r h oo g die bloed vloei na 70-90% van die q. 'n sp ier kan dan o o k s l e g s sy m a k s im a l e p resta sie le w er w a n n e e r al sy b lo e d v a te o o p is (p e te r­ so n en r en st rom 1986 p 87; sh ar key , 1985 p 21). d ieb ela ngrikste fis iologieseaanpassing in die liggaam a s gev olg van op w arm ing is eg ter 'n v erhog ing in lig g a a m s tem peratuur. die vo o rd ee l van 'n hoe li g g a a m s t e m p e r a tu u r en veral spier t e m p e r a t u u r , le d a a r i n d a t d ie m e t a b o l i e s e p r o s e s s e t e m p e r a tu ur a fh a n k li kis. v i r e l k e g r a a d s t y g i n g in lig g a a m s tem p e r a tu u r , styg die en s i e m a t i e s e a k tiw i te it , en d us die m e ta b o li es e reaksies in die sel geas s o s ie er me t die en e rg ie si st e m e, die s o g e n a a m d e q |() o f t e w el d ie m e t a b o l i e s e r e a k s i e t y d ,m e t 13%. daar vind dus 'n v in n ige r en m e e r volle dig e d is so si as ie van o , plaas va nuit die h em o g lo b ien en m io g lo b ien na die weefsel w a a rd e u r die s u urs to fv o o r s ien ing ty den s die o efen in g ve rbet er word die o k s ih em o g lo b ie n -d is s o s ia s ie k u rw e v er sk u if d us na regs. o p hierd ie m a n ie r v er h o o g die sp o rt m an se fisieke w e r k s v e r m o e (prestasie) o m d a t m e er o , b e s k ik b a a r is en daa r 'n a f n a m e is in die w ee rs ta n d van die p u lm o n e r e bloedvloei . so vr oeg as in 1947 het h o en ljimggren b ew y s dat na 'n b eh o o rl ik e o p w a r m in g w as die ver b et er in g in die 100m tyd 3 4 % (0,50,6 sek), die 40 0 m tyd 3-6% (1,5-3,0 sek) en d i e 8 0 0 m tyd 2,5-5,0% (4-6 sek). so o r tg e l y k e resultate is by s w e m ge vind (astrand en r od ah l, 1977, p 562; roy en irvin, 1983, p 39; fox en mathews, 1981, p 271; bro oks en fahe y, 1985, p 22; klafs en a rn h e im , 1981, p 98). u i t b o g e n o e m d e figure kan b a i e d u i d e lik w a a r g e n e e m word hoe die mak si m ale, su urs to fv e r b r u ik ( v o , . ), die h a rt fre k w e n s ie (hf), die la k taatk on s e n t r a s i e en q |{l ty d en s m a k s im a l e o efen in g direk ve rb and hou met die sp iert em p e ra tu u r. h o e h oer die s p i e r t e m p e r a tu u r was, ho e h oer w as die v o , en hf. d aar is eg te r ook b e w y s dat by 'n re k ta a lt em p e r a tu u r van m e e r as 40"c was d a a r 'n a fn a m e in die v o , a lh o e w el die arb eidstv d bv die h oogs te s p i e r t e m p e r a tu u r nie to e ge n eem het nie, was die lak taat ko n s en tr a s ie aa n s ie n li k laer. v er d e r blyk dit dat 'n to e n a m e van 1 0 ° c in s p i e r t e m p e r a t u u r d ie m e t a b o l i e s e reaksiety d ( q l0)v er dubb el en dat die k u r w e in die fisiologiese o m v a n g baie sk erp stvg (broo ks en fahe y, 1985, p21; fox en m a th e w s , 1981, p p2 71272). daar is v er der a a n ge to o n d a t d e u r die s p ie r g r o e p e v o o r 'n k r a ga ktiwiteit te oorlaai, dit tot 'n ver b et er in g in p r e s ta ­ sie lei. daar word v er m oed dat daa r 'n v e r h o o g d e vlak van p ri kk el in g van die m o to r e e n h e d e is wat o p g e ro e p word o m die v e r h o o g d e ar b e id sl a s te hanteer. hie r die m o to r e e n h e d e word dan oorg ed ra na die w erk li kh e id sp re s tasie me t 'n g e v o lg li ke to e n a m e in die s p o r t m a n se fisieke w erk sv er m oe . (kl afs en a rn h e im , 1981, p98). 2 k o o r d in a s ie o p w a r m i n g v er oo r s a a k 'n to e n a m e in s p i e r t e m p e r a tu u r met 'n gev o lg li ke v er b et er in g in k oordinasie. die re de is d at die s e n u w e e -i m p u l s e vi nn iger o ' s p o r t s m e d ic in e . v o l 4. n o 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) fisiologie b e w e e g b y h o e r t e m p e r a t u u r e n d a a r o m m oet die s p o r t m a n sy sp iert em p e ra tuur gee le veer hou om s o d o e n d e sy kon tra ksi es p oed en k oo rd in a si e te ver hoog ( astran d en r od ah l, 1977, p 562; pet erson en r en st r om 1986, p 87). met a n d er w o o r d e ,d a a r is 'n to e n a m e in die te m po van die n e u r o m u s k u le r e tr a n s m is s i e s ( o o r s e n d in g s ) en die o p r o ep van spierv ate, s o w el as die a k t i v e r i n g v a n d i e " n e u ­ ro m u s k u le re g e h e u e " vir die spe sif ie ke b e w e g i n g s wat nodig is vir die item (r oy en irvin, 1983, p 39). v er d e r ve r be ter o p w a n n i n g die sp o rtm a n se k oo rd in a s ie d eu r die o n tw ik k eli n g van die s p o r t­ man s e k in e s te tie s e g ew a a rw o r din g en vestig so 'n n e u r o ­ m u sk u le re pa tro on van presta sie. dit help d a n die s p o rt m a n om te bep aa l w a n n e e r hy 'n toestand van g er eed h ei d bereik het hy se g e w o o n lik " e k voel nou r e g " (klafs en a r n h e im , 1981, p 98. 3 v o o r k o m in g v a n b e s e r in g s p r o g r e s s ie w e o p w a r m in g lei tot 'n m erk b are a fnam e in d i e risiko vir bes eri ngs. dit v o o r k o m e n / o f ver m ind e r die s p a n n in g in, en die sk eu r van die sp ie rv ese ls v a n a f hulle tendi neuse aa n h eg ti n gs. dit vind g e w o o n ­ lik in die an ta g o n is plaas. die on ve r m o e van die an ta g o n is o m vinnig te verslap, plus die g ro ot kontrak tiele krag van die agonis, plaas die a n ta g o n is o n d e r g e w e ld ig e sp an n in g wat kan ve r oo rs a a k dat die spi er ve se ls s owel as die te n d o n a a n h e g tin g s kan skeur. d eu r m iddel van o p w a r m in g w o r d d i e l i g a m e n t e e n a n d e r k olla g en e u s e w eefse l g es tr ek o m so 'n g ro ter m ate van tleksiteit te v er se k er (pe terso n en r en st r om , 1986, 87; klafs en a rn h e im , 1981, p 98). barnard et al. het a b n o r m a l e ekg p at ro ne gevin d in 70% va n 44 nor m a a l w e g a s i m p t o m a t i e s e pr o b a n te tydens u it p u tte n d e o efen in g toe ge en v o o r a f o p w a r m in g g ed o en w as nie. t o e 'n 2 m in u u t o p w a r m in g (dr af op die plek) die o efen in g v o o r a fg eg a a n het, w a s al die p r o b a n t e se e k g pat rone n o rm a a l (a stran d en rodah l, 1977, p 5 6 3 ) . h ie r die v er sk ynse l word t o e g e s k r y f a a n 'n o n v o l d o e n d e b l o e d to e v o e r na die hart. (fox en m a th e w s , 1981, p 272). 4 p s ig o l o g ie s e v o o r b e r e id in g o p w a r m i n g dra by tot die v er w y d er ing van li gg aa m lik e s p a n n in g voor w e d y w e rin g . s p a n n in g is m e er op m e r k s a a m v oor w e d y w e r in g wat deu r o p w a r m in g v er m in d er word en tot 'n g ro te r m at e van o n ts p a n n in g lei. m e t o d e v a n o p w a r m in g ( o p w a r m in g s p r o g r a m ) o p w arm in g kan in tw ee ka teg oriee in g ed eel w ord , nan in iik: (i) a lg cm en e o f n ie-v erw an te op w a n n in g dit b eh e ls die a lg e m e n e o p w a r m in g va n die ligg aam en sluit in ak tiw iteite soos liggies d r a f en fle ksiteitsoefen inge; (ii) sp esifiek e o f v erw an te op w arm in g sluit in a ktiw iteite w a t so o rtg ely k is aan die wat in die v aa rd ig hei d van die item g eb ru ik word (klafs en a rn h e im , 1981, p98). 'n g e k o m b in e e r d e o p w a r m i n g s p r o ­ g ra m wat s a a m g es tel is uit ver ske ie n av o r s in g s tu k k e sal as volg daaruit sien: (i) fleksiteitso efen in g e m a t ig e e n b e p er kt e st re k kin g van spiere en spier g r o ep e van die hele ligg aa m en die w at g eb r u ik gaan word in die ak tiw iteit: (ii) stad ig e d ra foefen in g e beg in sta dig en v e r m e e r d e r g ele idelik die intensiteit, die o efen in g m o et aan sw et in g v er o o r s a a k en die liggaam s t em p e ra tu u r la a ts ty g ,b y v o o r b ee ld te m p o lo p e ; (iii) fle k siteitso efen in g s s ta dige en volle dig e st re k kin g van d ie spiere, s p ie r g ro e p e en g ew ri g te wat spesi fiek vir die va a rd igh eid / a ktiw it eit b en o d ig word; (iv) s p o r t s p e s i f i e k e o p w a r m in g s a k t iw it e it e b e s t a a n u it v a a r d i g h e i d s d r i l o e f e n i n g e w a t d ie ak tiw it eit e van die sp ort it em ins luit, bv hek kied ri lo efe n in ge. b e­ gin w ee r een s teen 'n m a tig e in ten ­ siteit en v e r m e e r d e r die intensiteit soos wa t hy voel sy li g g a a m s t e m p e r a tu u r styg en sy k a rd io v a s ku le re stelsels versnel. v oor beeld: bofbal d oen goeie, v e ld w e r k , k o l fw e r k en v a n g w e r k . h ierd ie tipe van oefen in g e het 'n tw eele d ig e doel: a) so rg d a t die s p i e r t e m p e r a tu u r en b loe d v lo ei o p ti m aal is in die s p i­ er e wat direk d e u r die s p o rtm a n g eb r u ik g a a n w ord , en b) vo o rs ie n 'n o p w a r m in g vir die h a n d -t o too g k oo rd in a si e en a n ­ d e r n e u ro m u s k u le r e m e g a n is m e wat d ir e k b etr o k k e is by die item (fox en m a th e w s , 1981, p 272; roy en irvin, 1983, pp 39-40; klafs en a r n h e im , pp 98-99). na die o p w a r m in g m o et 'n d ro e t h e m p a a n g e t r e k word om te voorkom s p o r t g e n e e s k u n d e v o l 4. n r 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) f © l c m l o l d at die spiere te g ou afkoel as gevolg v an sw eetverd am p in g. die positiew e voo rd ele v a n o p w a rm in g begin gou om te v erm in d er en die ideale tyd sver loop tussen die o p w arm in g en die a a n v a n g van die item m oet nie langer as 10-15 m in ute w ees nie (peterson en r en strom , 1986, p 88). tydsduur van opwarming die intensitiet en d u u r v an op w arm in g w ord bepaal d e u r die item en die fiks heidstatus van die sp o rtm an . 'n op w a rm in g sp ro g ra m w a t geskik is vir 'n g oed gekon d ision eerd e sp o rtm an sal versek er 'n sw ak gekondisioneerde sp o rtm an uitput. sp o rtm an aan tree vir sy item m o et hy sy sw eetp ak uittrek. by veld item s in atletiek m o e t die atleet w e e r sy sw eet­ pak aan trek na voltooiing v a n sy p oging, en indien hy te lank m o et w ag vir sy volgen d e p oging m o et h y ligte op w arm in gsoefen in ge tussen sy pogings u itv oer (klafs en a rm h eim , 1981 p 99). die ru sp erio d e tussen die opw arm in g en die item m oet h oo gsten s 15 m inute w ees, w an t na 45 m in ute is die v oo rd e lige invloed van die o p w arm in g gekan seleer en het die sp iertem p era­ tu u r teru ggek eer, na die pre op w arm in gsvlak k e (a stran d en ro dahl, 1977, p 563). tyd en s die item . baie atlete vind die u itv oerin g v an veral die strekoefen inge b aie ontsp an n en d (r oy en irvin, 1983, ; p 4 0 ; p eterson en r enstrom , 1986, p 88). v olgens fox en m athew s (1 981, p 273) is afkoeling absoluut noodsaaklik w eens die volgen d e tw ee fisiologiese redes: (i) die bloed en spierlaktaatvlakke d aal vin n iger tyd en s 'n arbeidsherstel as tyd en s 'n ru sh erstel; en (ii) m atig e oefening hou die sp ierp om p aan die g an g , dit voo rk om o p d am m in g van bloed in die ekstrem iteite en v erm in d er so die g e v a a r v a n floutes e n / o f duiseligheid n a oefening. source of graphs: brooks en fahey, 1985 fox en mathews, 1981 v e r w y s in g s a s t r a n d , p .o ., r o d a h l , k. t e x tb o o k o f w o rk p h y s io lo g y , (2 e u itg a w e ), n e w y o rk : m c g ra w -h ill b o o k c o., 1987. b r o o k s , g .a ., f a h e y , t .d . e x e rc is e p h y s io lo g y : h u m a n bio e n e rg e tic s an d its a p p lic a tio n s, l o n d o n : m a c m illa n p u b lis h in g c o ., 1985. f o x ,e .l . m a t f ie w s , d .k . t h e p h y s io lo g ic a l b a s is o f p h ysical e d u c a tio n an d a th le tic s. (3 e u itg a w e ), n ew y o rk : s a u n d e rs c o lle g e p u b lis h in g , 1981. k l a f s , c .e ., a r n h e im , d .d . m o d e rn p rin c ip le s o f a th le tic s t r a in in g , (5 c u itg a w e ), s t l o u is: c v m o s b y c o ., 1981. p e l e r s o n ,l ., r e n st r d m , p. s p o r ts in ju rie s, jo h a n n e s b u rg : j u ta an d c o. l td ., 1986. r o y ,s .a .,lr v l n ,r . s p o rts m e d ic in e , n e w j e r s e y : p re n tice -f la l) in c., 1983. s h a r k e y , b .j. p h y s io lo g y o f f itn es s, (2 e u itw a g e ), illin o is: h u m a n k in e tic s p u b]., 1984. die m eeste n av o rsers beveel 'n op w arm ingsperiode v an 15-30 m inute aan teen 'n relatiew e h oe tem p o v an ener gieverbruik (3,0 tot 3 ,4 liter 0 2/m i n of teen 'n h ard lo o p sp oed v a n 12-14 k m /h ). die d u u r en intensiteit van die o p ­ w a rm in g m oet ook aan g ep as w ord by die o m g e w in g ste m p e ra tu u r en klere drag. h oe h oer die o m g ew in g s­ te m p eratu u r is en hoe g roter die hoe veelheid klere w a t ged ra w o rd , hoe g o u er w ord die v erlan g d e lig gaam s­ tem p eratu u r v an 38,5°c bereik (spi­ ertem p eratu u r 39°c of h oer). dus 'n stygin g v a n o n g e v e e r 2°c w o rd v er lang (a stran d en r odahl, 1977, p 563; r oy en irvin, 1983, p 39; kalfs en a rnheim , 1981, p98). o p koel dae m oet die opw arm in gstyd v erlen g w o rd en m oet die o p w arm in g in 'n sw eet­ pak ged o en w ord . e ers w an n eer die h uidiglik glo baie sp ortlu i n og dat op w a rm in g hulle sal u itp u t, m a a r uit die v o o rafg aan d e bespreking is dit duidelik d at die sp o rtm an sy prestasie kan verb eter indien by korrek en o o r d e e l k u n d i g o p w a r m . 'n o p w arm in g sp erio d e van 15 m in ute w ord aan b eveel vir hoerskoolatlete. afkoeling die sportaktiw iteit m o et gevo lg w ord d e u r 'n afkoelperiode v an 3-5 m inute w a a r t y d e n s l a k t a a t ' en a n d e r m etaboliese p rodu k te uit die spiere en weefsel v e rw y d e r w ord o m spier styfheid en sp ierp yn te v erm in d er. strekoefeninge en liggies d raf m aak deel u it van h ierdie p ro g ra m . v erd er gee dit die sp o rtm an geleentheid om kalm en ru stig te w o rd (fisies en psi gologies na die afskeiding van groo t hoeveelhed e epinefrien (adrenalien) q ^ s p 0 r t s m e d i c i n e . v 0 l 4 . n 0 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) middels in sport: resultate v er k r y tyd en s die sa sen io r a tletiek k a m pio n sk a ppe van 1988 en 1989 p j v a n d e r m erw e p h .d ., n at. sci. o p s o m m in g siftingsm etodes w aarin g asch ro m a tografie en g a sch ro m a to g ra fie / m assa sp ek trom etrie gebruik i s , is u itg evo er op 124 u rienm on sters w at tyd en s die sa senior a tletiekbyeenkom ste van 1988 en 1989 v ersam el is in 'n poging o m die gebruik v an v erb od e m iddels aan te toon. m iddels w a t d e u r die internasionale o lim p iese-k om itee as v erb od e verk laar is, is in 4% v an die u rienm on sters aan getoon . die resul tate toon duidelik d at atlete onw etend m ed isyne gebruik w at v erb od e m id dels b evat of m iddels b evat w a t hulle prestasie nadelig kan beinvloed. in l e id in g die eerste toetse vir die gebruik van verb od e m iddels d eu r atlete in suid a frik a is ty d e n s d ie sa s e n io r a tletiekbyeenkom s v an 1983 gedoen toe 10 0 u rien m on sters v e rsa m e l en g eanaliseer is.1 sedertdien w as die gebruik van v erb od e m id d els in sp ort in 'n poging o m p restasie te verb eter verskeie kere die o n d e rw e rp v an w ye nuusdekking gew ees. h ierdie verslag handel o o r die resul tate w a t v erk ry is d e u r die analise v an 124 u rienm on sters w a t tydens d ie s a senior atletiekkam pioenskappe van 1988 en 1989 v ersam el is. m a t e r ia a l e n m e t o d e in die tw ee jaar is 124 u rienm on sters v ersam el al die m ed aljew en n ers van 1988, 'n totaal v a n 95, en al die atlete w at eersteplekke behaal het in 1989, 'n totaal van 29. h ierd ie u rienm on sters is geanaliseer d e u r tw ee siftin gp rosed u res: m etod e a vir die teenw oord igh eid van stim u lasie en a n d e r b asiese verbindings m et behulp v a n g asch ro m atro g rafie (gc) en m etod e b vir die teenw oord igh eid v a n anaboliese steroiede m et behulp v a n g a s c h r o m a t o g r a f i e / m a s s a sp ek trom etrie (g c /m s ). alle ver bindings w a t d eu r m etod e a aangetoon is, is bevestig m et g c /m s . r e s u l t a t e e n b e s p r e k in g in 1988 w as d a a r 29 (30,5% ) u rien m on ­ sters w a t v reem d e verbindings b evat het teen o o r die 8 (27,6% ) in 1989. tabel i toon die verbindings w a tg e iden tifseer is m et gc en g c /m s vol g ens m eto d e a. m etod e b het geen anaboliese ste ro ie d a a n g e to o n nie. die 39 v erbindings w a t in 1988 geidentifiseer is het in slegs 29 uri­ e n m o n s te r s v o o r gekom en die 11 verbindings w a t in 1989 geidentifiseer is het in 8 u rienm on sters v o o rg e k o m w a t aan dui d at so m m ige uri­ en m onsters m eer as een verb in d in g b evat het. die v erb od e m id dels w a t in 7 u ri­ e n m o n s te r s v o o r ­ gekom het w as f e n k a m f a m i e n en m e t a b o l i e t ( l ) , f e n ie lp ro p a n o la m ie n (3),k od eien (2)en efed rien (3). die konsen tra sie sv a n e fe d rie n in die 2 u rienm on sters w as eg ter te laag om as 'n positiew e resul taat b eskou te w o rd (volgens intern asion ale bepaling). a n tih istam iene, w at som s saam m et ander verbindings soos efedrien, kafeien en antibiotika in dieselfde u rienm on ­ sters v o o rg ek o m het, w as in 11 m o n sters teen w o ord in g. h oew el antihistam iene nie v erb od e m iddels is nie gee dit o n gew enste new e-ef fekte so o sslap erigh eid , duiseligheid, sp iersw ak h eid , v erlaag d e konsen tr a s ie v e r m o e en g e b re k aan koordinasie, alm al w a t die prestasie v a n atlete n ad elig kan beinvloed. kafeien w o rd as 'n v erb od e stim ulant beskou as dit in konsentrasies h oer as 12 n g / m l in die urien voorkom . d aar w as 10 u rienm on sters w at 'n kafeienkonsentrasie tussen 5 en 12 (j.g/m l (hoogste 10,5 (j.g/ml) gehad het. h ierd ie vlak kan nie maklik v e rb in d in g s g e id e n tifise e r d eu r g a sc h ro m a to g ra fie en g a sc h ro m a to g ra fie /m a s sa s p e k tro m e tr ie verbinding frekwensie 1988 1989 o ksatom ied flu o xatien en m etaboliet o rfen ad rien d oksilam ien p irim etam ien fenielprop an olam ien fenfram ien en m etaboliet k odeien f enk am fam ien en m etaboliet d iklofenac 2 t rim etop rim 2 e fed rien 2 c hlorokien en m etaboliet 3 c hlof enir arm en en m etab oliet 7 n ikotien 7 kafeien (hoer as u g / m l ) 7 v erap am il en m etaboliete_______ 0 1 to ta l 39 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) farmakologie v s * / # > & * ^ ' v / v < / . y* b er eik w o rd d e u r die n o r m a le in ­ n a m e van a ll ed a a g s e kaf eien -b ev at tende d ra n ke s o o s koffie, tee en coc a cola nie2-3 en dit w ee r s p ie el die ge w il d h e id van k a fe ie n -b e v a tt e n d e ton ik u m s o n d er o n s atlete. na d ee glik e b e s tu d e r in g van al die g e g e w e n s is sleg s 3 u r ie n m o n s ters (3,2%) in 1988 en 2 ur ie nm on st er s (6,9%) in 1989 as po si ti e w e resul tat e gerap porteer ; 'n g e m i d d e ld va n 4%. s a m e v a t t in g h o e w e l slegs 4% van die v er s a m eld e u r ie n m o n s t e r s v er b o d e m id d e ls bev at h et w a t as po si ti ef g er a p p o r tee r is, w a s d a a r 'n g r o o t aan ta l m onsters w a t a n d er v er b in d in g s be v a t het w a t hoofs a a k li k a f k o m s t ig is v a n a f m e d i s y n es w a t vir g riep en v er k o u e ge b ru ik wor d. h ier d ie si tuas ie is nie t y d e n s a n d e r s a s e n i o r a t le ti e k b y e e n k m o m s t e w a a r b y se d ert 1983 getoets is, o p g e m e r k nie. veral d ie g eb r u ik v an a n ti h is ta m ie n e w ek k o m m e r . d ie op lossm g van d ie p robleem le veral in d ie volg en d e: 1. g e n e e s h e r e m o et b e w u s w ee s d a a r v a n d a t s o m m ig e griep-, v e r k o u e e n h o e s p r e p a r a t e v er b o d e m id d e ls be v a t en d us nie deu r s p o r t m a n n e g eb r u ik m a g word k or t v oor o f ty d en s b y e e n s k o m s te nie. d ok te r s m o e t nie su lke m e d i s y n e a a n d e e l n e m e r s v o o rs kryf n ie o m d a t die ve rto o n v an 'n v o o r s k r if nie die s k uldigh e id van 'n atlee t o p h ef nie. 2. d ie o n us rus in die finale instans ie no g b y die s p o r t m a n o m se ker te m a a k dat hy nie o n w e te n d enige m e d i s y n e g eb r u ik wat v er b od e m id d e ls of a n d e r m id d e ls w a t sy pre stas ie s k an b en a d e el, b e v a t nie. d a n k b e t u ig in g s die skryw er w il graag sy opregte dank betuig aan m ej h sl k ruger vir haar bydrae tot die analise van die urienm onsters asook aan die suid-afrikaanse a m ateur a tletiekunie vir hulle sam ew erkin g. f o r t h e v e r y o l d a n d t h e v e r y y o u n g : n e w v o l t a r e n 1 2 ,5 m g s u p p o s it o r ie s . c ib a g e ig y ar e pleased to a n n o u n c e the in tro d uc ti on of v o lt a ren s u p p o s i­ tories 1 2 ,5 m g a n d 25mg . in te nd ed pr im ari ly for y o u n g chi ldren and the elderly the n ew d o s a g e for m will c o m p le m e n t the loomg s tre ngth o f v o lt a r en supp osit orie s. t h e s u p p o s it o r y d o s a g e for m offers pro v en a n ti -i n fla m m a to r y , an alges ic an d an ti p y re tic prope rtie s w ith s e v ­ eral benefits: g u a ra n te e d d osage. c o m p li a n c e is en s u re d an d the co rrec t d o s e is a d m in is te red . r a p id se ru m levels. w h e n g iven rec tally, p e a k levels are ac h iev e d wit hin o n e hour. s h o rt h a lf-life . a llo w s d o s a g e fle xi­ bility. t h e s u p p o s it o ry is ide all y su ited for p o st -o pe ra ti v e p a in a n d in fla m m ation. detai ls from c ib a g e i g y (o il) 9 2 9 -2 2 3 7 literatuur ver wysin gs 1. h u n d t h k l , v a n d e r m e r w e p] e n v a n v e l d e n d p ( 1 9 8 4 ) d r u g s i n s p o r t : a r e p o r t o f l a b o r a t o r y i n v e s t i g a t i o n i n t o t h e p r e v a l e n c e o f t h e i r u s e i n s o u t h a f r i c a . s . a f r . m e d . j . , 6 6 , 8 7 8 8 8 . 2 . v a n d e r m e r w e p j , m u l l e r f o e n m u l l e r f . ( 1 9 8 8 ) c a f f e i n e i n s p o r t : a n i n v e s t i g a t i o n i n t o t h e u r i n a r y e x c r e t i o n o f c a f f e i n e in h e a l t h y v o l u n t e e r s a f t e r i n t a k e o f c o m ­ m o n c a f f e i n e c o n t a i n i n g b e v e r a g e s . s . a f r . m e d . j . , 7 4 , 1 6 3 1 6 4 . 3 . s e i f a r t h f , v a n v e l d e n d p , e s t e r h u i z e n m , p a r k i n d p , v a n j a a r s v e l d p p . ( 1 9 8 7 ) k o n s e n t r a s i e s v a n k a f f e i e n i n u r i e n : r i g l y n e v i r d i e a t l e e t . s a s p o r t g e n e e s k u n d e t y d s k r i f , 2 , 1 2 1 4 . c) s p o r t s m e d i c i n e . v o l 4. n o 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) rugby-serious injuries catastrophic rugby injuries of the spinal cord: an increasing problem a lan t. s ch er, m .b ., c h .b ., d .m .r .d . in t r o d u c t io n in 2 pr ev io u s p a p e r s 1:2 , i have rep orte d on 50 pa tients a d m it te d to the spin al c o rd inj ur y c en tr e at c o n r a d i e h o sp ita l in c a p e t o w n from 1964 to 1980, with para lysi s d u e to r u g b y injuries to the ce rv ica l spinal cord. since the first pa pe r, p u blish ed in 1976 1 there has b ee n co n si d er ab le d isc uss io n as re ga rd s r e d u cin g the in cid e n ce of these ser ious injuries and va ri ou s ch a n g es to the rule s ha ve been int roduc ed. in an at tem p t to ascert ain w h e t h e r fo llo w in g on these rule ch a n g es , there h as bee n any d ec r ea s e in the in cid e n ce of, or ch an g e in the m e c h a n is m of, these injuries, an a naly sis of the case histories and the r a d io g ra p h s of all r u g b y players a d m it te d to the s pin al c ord injury c en tr e d ur in g the 7 y e a r p erio d 1981 to 198 7 has b ee n m ad e. f in d in g s a total of 38 pl ay ers w ith cervical spinal cord injury ei ther p e r m a n e n t or te m p o ra ry , w er e identified. nine (24%) o f the pl aye rs w e r e 17 years of ag e or u n d e r at the time o f injury. t h e dis tr ibution o f the levels o f inj ury are s h o w n in t ab le i. n o t a b le is the high p e rce n ta g e (32%) of pl a ye rs w h o su stai ne d inju ry at the c 4 / c 5 level. a lan t. scher, m .b ., c h.b ., d .m .r .d . d ep artm en t o f r ad iolog y t y g erb erg h osp ital an d u n iversity o f s tellen bosch p .o .b ox 63 t y g e r b e r g 7505 t w o pl ay ers w e re inju red at the c2 level a n d 10 players s h o w e d no ev i­ d en c e of or th o p a e d ic inju ry on x-ray ex a m in a ti on . t h e m a jo ri ty of injuries w e re su s ta ine d eithe r in the s c ru m (39%) or d urin g tackles (42%) as s h o w n in t a b le ii. th is is in k eep in g with the f in d in g s in p re v io u s an aly ses. u a w id e s p e c t ru m of o r th o p a e d ic injuries w er e su st ain ed , b u t the m a jo r it y of p lay ers (66%) su st ain ed their injuries as a resul t o f p u re flexion violen ce or a c o m b in a tio n of flexion an d rotation. n o t a b le w a s the high n u m b e r of fle x­ ion d is clo ca ti o n s su sta ined co n se quen t u p o n co lla pse of the scrum. fifteen (39%) of the pl ay ers w er e in ­ jure d in scrum s. th is figu re co rrelates w'ell with the 40% in cidence of sc ru m inju ries n ote d in m y pre v io u s a n a ly ­ ses 1,2 an d also w ith in te rn ational ex p e r ie n ce .3-4 t h ir te en of the 15 p l a y ­ ers w ere in ju re d as a re sul t o f co llaps e o f the s c r u m , the m a jo ri ty o f these b ei n g pl aye rs in the front ro w , either p ro p s or h ooke rs . o n e p la ye r w as injured by c r a sh in g of the tw o p acks of f o r w a r d s w ith the injured p la ye r b e i n g ca u g h t u np re p a r ed . p ic c o u rte sy o f sa sp o rts illu strated s p o r t g e n e e s k u n d e v o l 4 . n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) six p layers su stain ed com plete, p erm an en t q u ad rep leg ia. the m ajor­ ity of o rth o p aed ic injuries sustained (table iii) w e re a n terio r d isloca­ tions, either bilateral o r unilateral. t a c k le in ju ries. sixteen (42% ) of p layers w ere injured d u rin g a tackle (table ii). the n eu ro ­ logical deficit w as less severe and only 4 p layers sustained co m p lete p a ­ ralysis. the sp e ctru m of orth o p aed ic injury (table iii) v aried con sid erab ly from the injuries sustained d u e to scru m m in g. this w id er variation of o rth o p aed ic injury and lesser degree of n eu rological deficit is in keeping w ith the m o re v aried m echanism . o ne p lay er w as injured as a result of a double tackle. o f p articu lar note and cau se for co n cern , is the observation that 6 p lay ers w ere injured as a result of a high tackle aro u n d the neck. the overall p ercen tage of injuries sustained in tackles has increased w hich is in keeping w ith the findings of silver 5 in ju rie s su stain ed in ru ck s an d m au ls. o nly 4 (10% ) of the p lay ers w ere injured in these ph ases of the gam e. this low p e rce n ta g e is som ew h at su rp risin g, as in a p rev io u s an aly ­ sis2a 20% incidence w as record ed . silver, rep o rtin g on 63 p layers in­ s p o r t s m e d i c i n e . v o l 4. n o 1 jured in e n glan d , co m m en ts on an increase in the p e rce n ta g e of p layers injured in ru ck s an d m au ls.5 the reason for this significant d ecrease in the p ercen tage of p lay ers injured in ru ck s and m auls is n o t clear. c o n c l u s io n d uring the p eriod 1 964 to 1980, 50 ru g b y p lay ers w ith cervical spinal cord injury w ere ad m itted to the spi"... the in cid en ce o f ru g b y spinal cord in ju ries in the c a p e p ro v in ce has not decreased " nal c ord injury c en tre a t c on rad ie h osp ital,2 an a v e ra g e of 3 p lay ers a year. d uring the p eriod u n d er rev iew in the p resen t p ap er (1981 to 1987) 38 p lay ers w ere ad m itted , an a v e ra g e of 5 ,4 p lay ers a year. this ind icates that d espite increased public a w aren ess of serious ru gby spinal injuries and considerable am en d m en ts to the rules, the incidence of ru g b y spinal cord injuries in the c ap e p ro vin ce has not d ecreased . silver an d g ill6 co m m en t on the gratifyin g d ecrease of serious cervical spinal cord injuries in ru g b y p lay ers in the u n ited k in gd om , w ales an d n e w z ealan d , but n ote that the only co u n try w h ere there h as n ot been a d e crease in the incidence is south a frica. a s co m m e n te d on in p r e v i o u s p a ­ p e rs,1,2 an d also in re p o rts from o v e r­ seas 4, flexion re ­ m ains the m o st im ­ p ortan t m echan ism of injury. the tw o p h ases of the g am e w h ere m ost serious injuries o ccu r are a gain identified to be the scru m and the tackle. fou l p lay w as re ­ sponsible for a sig­ nificant n u m b er of injuries. a p art from the single instance, w h e re a p la y e r w a s injured b y cra sh ­ ing of the scru m , a disturbin g n u m ­ ber of p lay ers w ere injured by the high tackle. d espite p rev io u s co m ­ m en t on the d a n g e r of this illegal play-7 no d ecrease in these avoid able injuries has taken place. r e f e r e n c e s 1. s c h e r a t . r u g b y in ju ries to th e c e rv ic a l spin al c o r d . s a fr m ed j 1 9 7 7 ; 5 1 : 4 7 3 -4 7 5 2. s ch e r a t . r u g b y in juries of th e sp in e a n d sp in a l c o rd . c lin s p o rts m ed 1 9 8 7 ; 6 (1 ): 8 7 9 9 .1 2 . 3. b u r ry h c , g o w la n d h . c e rv ic a l in ju ry in fo o tb a ll a n e w z e a la n d s u r v e y . br.j s p o rts m e d 1 9 8 1 ; 15: 5 6 -6 0 . 4. w illia m s p a n d m ck ib bin b. u n sta b le c e r v i­ ca l sp in e in juries in ru g b y a 2 0 -y e a r re v ie w . in ju ry 1 9 8 7 ; 1 8 (5 ): 3 2 9 -3 3 2 . 5. s ilv e r jr , injuries of th e sp in e s u s ta in e d in r u g b y . b r.m e d j 1 9 8 4 ; 2 8 8 : 3 7 -4 3 . 6. s ilver jr, gill s. inju ries of th e s p in e su sta in e d d u rin g ru g b y . s p o rts m ed . 1 9 8 8 ; 5: 3 2 8 -3 3 4 . 7. s c h e r a t . t h e h igh r u g b y tack le a c o n tin u in g m e n a c e . s a fr s p o rts m ed 1 9 8 1 ; 1 1 : 3. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychosocial factors and sports injuries andre moller department of psychology, university of stellenbosch d uring the p ast tw o d e ca d e s there has been a g row in g a w aren ess of the asso ­ ciation betw een p sy ch o lo gical factors and sp o rts p erform an ce. in p articu lar the effectiveness of v a rio u s p sy ch o ­ logical techniques and p ro ce d u re s in im p rov in g p erfo rm an ce w a s exten ­ sively research ed . h o w e v e r, a rev iew of the literature rev ealed that v e ry little system atic research has been d on e on the possible relationship betw een p sy ­ ch ological factors and sp o rts injuries. the genesis of injury is con sid ered a co m p lex, m ultifactorial p ro cess. the only p sy ch o lo gical v ariab le studied in this regard is stress. findings by holmes & r ahe (1967) that the o nset of illness is significantly associated w ith an in­ creased p ercep tion of stressful life events, w as exp an d ed into the field of life stresses and athletic injuries by b ram w ell, m asu d a, w a g n e r & h olm es (1975). their stu d y sh o w ed that an injured g ro u p of football p lay ers had a significant h igher life stress level than the non-injured g rou p . t h ey divided p lay ers into low -risk, m od erate-risk and high-risk g rou p s on the basis of low , m o d e ra te and high life c h ange units. in the low -risk g ro u p 30 p e r­ cen t of the p lay ers suffered injuries. in the m o d erate-risk g ro u p 5 0 p ercen t of the p lay ers suffered injuries, w hile in the high-risk g ro u p 73 p e rce n t of the p layers suffered m ajor tim e loss in­ juries. sim ilar results w ere rep o rted by sara son, joh nson & siegel (1978). c od din gton & troxell (1980) co n d u cted a sim ilar stu d y on high school football p layers. they found significant differ­ ences b etw een the injured an d n on ­ injured athletes for the facto rs of fam ­ ily events an d object loss. six p layers re p o rte d d iv o rce of their p aren ts, and four p lay ers re p o rte d d eath of a p a r­ ent. the research ers co n clu d ed that the risk of injuries for these p layers w as five tim es g re a te r than for those rep o rtin g no su ch loss. in a recent study, m ay, veach, southard & h e rrin g (1985) studied n in ety-seven elite m ale and fem ale athletes (biath­ lon, ra c e w alk in g, figu re skating, gym nastics and basketball). their study again d em o n strated that "th e a m o u n t of life ch an ge is an im p ortan t force in an in d ivid u al's life w hich m a y influ­ ence the onset of injury" (p.177). a th letes, especially those e xp eri­ encing high life ch an g es w hich can lead to considerable an xiety reg ard in g p erfo rm an ce, ended u p actu ally e x p e ­ riencing problem s. a s w ou ld be exp e cte d , these individuals had se v ­ eral health problem s w hich are co m ­ m o n ly related to stress, su ch as h ead ­ aches, d igestive tract d isturban ces, an xiety an d substance use. the a u th o rs con sid ered the u se of n on ­ p rescrib ed m ed icatio n by these athletes as of p articu lar interest. they arg u e d that these individuals w ho exp erien ced high d egrees of ch an ge w ere so anxious that they avoided going to the a p p rop riate health ca re p ra cti­ tioner. this self-m edication leads to m o re p roblem s, and therefore, their health an d p erfo rm an ce d eterio rated even m o re. a n o th er interesting find­ ing of this stu d y is that the you n ger, d evelo p m en tal athlete tend ed to be m o re v ulnerable to life stresses. it m ay w ell be that the y o u n g e r, d ev elo p m en ­ tal athlete h as n ot yet learn ed the p sy ­ ch ological cop in g skills o r the p sy ch o ­ logical p rep aratio n skills to be as effi­ cient o r con sisten t as the elite athlete. a ccord in g to these researchers the effect of life ch an g e and the ensuing stress m a y be to h in d er co n cen tration on en viro n m en tal cu es that a re crucial a n d /o r to block p reviou sly learned ad ap tiv e resp o n ses w hen difficult and potentially d am ag in g situations are recog n ized . a cco rd in g to n iedeffer (1981) this also explains w h y som e athletes n ever seem to re co v e r co m p letely from an injury. this failure is often seen in the case of knee injury. w h at h as h ap p en ed for the injured athlete is that the pain and a n xiety g en erated by the injury (fears of future injuries) result in his being m o re atten tiv e an d sensitive to this area. a tten tion is d istracted from the u su al cu es to w hich the athlete a t­ tends. h e begins to look for som eon e com in g from the side instead of ru n ­ ning w ith the sam e relaxed feelings he had p rior to the injury. p erfo rm an ce is inhibited by the attentional d istrac­ tions. in ad d ition , m u scle tension increases th ro u g h bracing an d a desire to p ro te ct the knee. a s a result, flexi­ bility on the playing field is red u ced ev en th ou gh it isn 't red u ced in the lab or test situation. g iven these ch an ges the athlete d oesn 't p erfo rm as well and increases the likelihood of fu ture injuries b ecau se of the re d u ction in flexibility (p l4 8 ). t hese results on stress an d injury co n trad ict the co m m o n m y th that a c­ cidents o ccu r as a n atu ral p ro cess of a sp o rt o r are the p hysical h a z a rd s of a p articu lar activity. these stu d ies su g ­ gest that one co m p o n en t of injury and illness is an en viron m en tal or p sy ch o ­ logical factor. the con seq u en ce of this finding is that the b ehavioral co m p o ­ nent is poten tially preventab le (m ay et al., 1985, p. 178). s p o r t g e n e e s k u n d e v o l 4. n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychology w h a t are the p sy ch ologic al c o n s e ­ q u en c es or c o n c o m it a n t s of injury and how is future p e r fo r m a n c e influenced by pr ev io u s inj ury? ag ain , very little r esearch has been d on e on this issue. acco rd ing to rotella (1985) the research by kiib lerr os s (1969) on the stages of death and d yin g offers the best c o n ­ ceptual fr a m ew o r k within which to un d ers ta n d the p sy ch ologic al c o n s e ­ q u en c es of ath letic injury. acco rd in g to this model , a loss (e.g. death of a loved one, d iv o rc e, a m p u ta tio n , etc.) is an ex tre m e ly stres sful expe rience w h ic h will trig ger typical p h y s io lo g i­ cal and psy chological responses. sports injuries, a cc o rd in g to this theory, also co n st it ute a loss, i.e. loss of the ability to prac tise and perfo rm . injured a th letes w oul d th e r ef o r e p ro g r es s throu gh sim ilar and p re d ic ta bl es ta ges . th is re sp onse pattern is typified by the fol low ing em otio n a l co m p on e n ts : a pro tection a gain st the negativ e e m o ­ tions a c c o m p a n y i n g injury and may h a m p e r the pro ce ss of a c c ep ta n ce and reco very. sho ul d the inju ry persist, m o m e n t a r y isolation and lone liness m ay follow. as they b e c o m e a w are of the ex ten t of the injury they a d v a n c e thr ou gh the fol low ing stag e which is typified by an ge r and ag gressio n (p. 276). a n g e r a n d a g g r e s s io n t h e a th le te b ec o m es irritated with h im s elf and directs his irritability a gain st family, friends or p eop le who w a n t to help. he m a y protest ag ain st o r resist treatment. h e m a y b la m e an o p p o n e n t for a g gr e s s iv e play or h im ­ self for insufficient p re pa ra tion. often it is expressed in m o re su btle ways an d thus is less o b v io u s, e.g. th ou gh ts like " w h y did this h a p p e n to m e ? " occur. d e n ia l b a r g a in in g a c co r d in g to rotella (1985) it is n o r ­ mal for a th ­ letes, imrne■ d i a t e l y f o l ­ lo w ing an in­ ju r y , to re ­ spond by stat­ ing that there is no dam ag e, it is less e x ­ tensive than o r i g i n a l l y thou ght , or it will pro ba bly be bette r to­ m o rr o w . it m a y be m a n i­ f e s t e d in k e e p i n g an in ju r y fro m t h e c o a c h , m i n i m i s i n g the severity of an injury or r e f u s i n g to see a p h y s i­ cian. denial also serv es as t h e next stage is hera lded w he n the a th le te b eg ins to bargain, e.g. " o k , i'm injured but 1 m u st be able to play in time for the pl ayo ffs ". a c co r d in g to rotella (1985) this stage is typified by a true se ns e of loss. th e a th le te o bse rv es a leg in a cas t o r an arm in a sling and he is well a w a r e that the injured lim b is the d if fer ence betw ee n obs er v ing action from the sidelin es and p e r fo r m ­ ing in the com p etitio n. id ent ity has been lost and a perception is formed that the loss m a y also be the te a m 's loss (p. 276). d e p r e s s io n a n d g u il t t h e athlete m ay ex p e r ie n ce a d ee p em p ty feeling, ev en with o ut bu rs ts o f crying. fe el ings o f d e s p a ir ma y su rf ac e (e.g. "i will nev er be ab le to p e r fo r m eff ec tiv ely a g a i n " , or " 1 m ay n e v e r c o m e back to full strength ag ain"), a c c o m p a n ie d by neg ative self esteem and phy sical s y m p to m s su ch as re st­ lessness, n au s ea , loss of ap pe tite, poor sleep, etc. fee lin g s of guilt are c o m ­ mo n (e.g. "1 ha ve let my coac he s, t e a m ­ m ate s, friend d o w n by gett ing s p o r t s m e d ic in e . v o l 4. n o 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychology n ext up in sports m ed icin e in ju re d ") and m a y even aris e from his a g gre s s iv e feelings or feeling s of jea l­ ousy (envies o ther heal thy athletes). a n x i e t y it m a y arise from th ou gh ts like " w h a t is g oin g to h a pp en to me n o w ? " "how' am 1 goin g to c o p e ? " " w h a t ar e my ch a n c e s ? " or m a y be d ue to a feeling of loss of control ove r his em otions. a n x ie ty is co nsi der ed a c o m m o n c o n ­ s e q u e n ce of injury. a c c o r d in g to ro tella (1985) an xie ty related to an injury ma y lead to reinjury, injury to an other part of the b o d y due to forcing the recently injured limb, a te m po ra ry p e r fo r m a n c e d ec r e m e n t d u e to lo w ­ ered co n fid e n ce and p e r m a n e n t loss of c o n fid e n ce and ab ility to p e r fo rm (p. 273). it is also often hyp oth es iz ed that " i n ju r y p ro n e " athletics m ay be a m o n g the m o r e an x io us and in s e cu re c o m ­ petitors, but ex cep t for a few studies there is little corr ob o ra tio n of this re la­ tionsh ip (cratty, 1983). m o re research needs to be d o n e d ea lin g with this int ric ate int eraction betw een injury and anxiety. th e s e em o tio n a l c o m p o n e n ts are not co n st a n t and a lw a y s present: it can a p p e a r in any order, with v a ry in g in­ tensity and im p o rt a n c e for different persons. h o w ev e r , a k n o w l e d g e of these factors is im po rta nt, b ec a use it will en a b le the coach or trainer, the ph ysician a nd o th e r p ers ons atten d in g to the injured athlete to bette r u n d e r ­ stand his re actions and im p r o v e the qu ality of their care. in co n c lu si o n , injuries in all sp ort s are inc reasing d es p ite te ch no logic al a d ­ va nce s in safety e q u i p m e n t (b r a m w ell et al., 1975). h o w ev e r, a revie w of the li terature reveal s that the re lationsh ip be tw ee n ps ych ologic al factors and spo rts inju ries as well as the p s y c h o ­ logical rehabilitation of the injured athlete are rather neg lected areas in research. i m p or ta n t qu es tio n s re m ain u n a n ­ sw er ed , e.g.: ap ar t from stress, do o ther p sy ch olog ic al va riable s such as self es te em , co n cen tr a ti on , att ent ion, co pin g skills, etc. con trib u te to injury? w h y d o ce rtain athle te s see m to be m o re pr o n e to injury than others? w h y do so m e in d iv id u als nev er see m to reco ve r co m p le tely from an injury? w h a t are the p sy ch olog ic al c o n s e ­ q u en c es of injury and ho w can they be dealt wit h? it is ev id en t that in future, cl ose r re­ search atte ntion will have to be given to the role of p sy ch olog ic al factors in sports injuries. existing findings, h ow ev er , su gg es t that those involved in the training and care of athletes must be a w a r e of em o tio n a l c o n d i ­ tions that m a y con trib u te to injury, and thereby assist in re du ci n g the p sy ch o lo g ic a l risk c o m p o n e n t and in ­ jury rate. t e a m ph ysicians, trainers and c o a c h es m u st also pay clo se a tt e n ­ tion to the p sy ch o lo g ic al re habil itation of the injured athlete. t h a t the b o d y is re ady to return to co m p eti ti o n d oes not im p ly that the mind is also p re ­ pared. failu re to attend to the p s y c h o ­ logical co n s e q u e n c e s of inju ry m ay increas e the risk of rein jury and a d e t e ­ rioration of pe rfo rm ance. references b r a m w e l l , s . , m a s u d a , m . , w a g n e r , n . & h o l m e s , t ( 1 9 7 5 ) . p s y c h o s o c i a l ( a c t o r s i n a t h l e t i c i n j u r i e s , l o n r n a l o f h u m a n s t r e s s , 1, 6-211. c o d d i n g t o n , r . & t r o x e l l , j ( 1 9 8 0 ) . t h e e t t e c t s o f e m o t i o n a l f a c t o r s o n f o o t b a l l i n j u r y r a t e s , lo u r n a l o l h u m a n s t r e s s , 4 , 2 5 . c r a t t v , b.|. ( 1 9 8 3 ) . p s y c h o l o g y i n c o n t e m p o r a r y s p o r t ( 2 n d e d . ) . n e w j e r s e y : p r e n t i c e h a l l . h o l m e s , t & r a h e , t . ( 1 9 7 6 ) . t h e s o c i a l r e a d j u s t ­ m e n t r a t i n g s c a l e . j o u r n a l o f p s y c h o s o m a t i c r e s e a r c h . h , 2 1 3 2 1 8 . k u b l e r r o s s , e. ( 1 9 6 9 ) . o n d e a t h a n d d y i n g . n e w y o r k : m a c m i l l a n . m a y j . r . , v e a c h , t . l . , s o u t h a r d , s . w . & h e r r i n g , v i . w . ( 1 9 8 5 ) . in n . k . b u t t s , t . t . g u s h i k e n & b. z a r i n ( e d s . ) j h e e l i t e a t h l e t e . n e w y o r k : s p e c ­ t r u m p u b l i s h e r s . n i d e f f e r , r . m . ( 1 9 8 1 ) . t h e e t h i c s a n d p r a c t i c e o f a p p l i e d s p o r t p s y c h o l o g y n e w y o r k : m o n v e m e n t p u b l i c a t i o n s . r o t e l l a , r. j. ( 1 9 8 5 ) . t h e p s y c h o l o g i c a l c a r e o f t h e i n j u r e d a t h l e t e . in l . k . b u n k e r , r. j . r o t e l l a & a . s . r e i l l y ( e d s . ) s p o r t p s y c h o l o g y . c h a r l o t t e s v i l l e : d e p t , o f h e a l t h a n d p h y s i c a l e d u c a t i o n . s a r a s o n , j . g . , j o h n s o n , j . h . & s i e g e l , j . vi . ( 1 9 7 8 ) . a s s e s s i n g t h e i m p a c t o f l i f e c h a n g e s : d e v e l o p t h e next issu e of s p orts m ed icin e w ill co n tain , am o n g st o th ers, the fo llo w in g a rticles: s p orts in ju ries: su rvey at bureau f or studen ts healt h -u n iv er sity of the ofs. e p rinsloo. s w im m in g : e p i d e m i o l o g i c a l s t u d y of failure to co m p le t e a long d is ta n ce swim. d erek yach. s tren g th f itn ess: a b iom e ch a n ica l a pp r oa ch m el siff. p h y s io th e ra p y : s o c c e r : w a r m i n g u p and st retc hin g. g ary jacobsen . n u tritio n : e ner gy v al ue of food m ie k e faber. g en eral: a cut e ca u li flo w er ear. jd a b ekker. c o n g re sse s: r ep o rt -b a c k on sp orts m e d i ­ cine con gre ss . p l u s : d e ta ils o f "b e st a rticle " c o m p e titio n . s p o r t g e n e e s k u n d e v o l 4. n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) letters to the editor injury rehabilitation with machines. d ear sir, i w ou ld like to co m m en t on the article by m .c. siff "in ju ry rehabilitation w ith m ach in es" in the v olu m e 3 n o. 2 1988 issue in w hich he d iscu sses the u se of m achin es in rehabilitation. t h ere is definitely no one typ e of exercise m achin e that can offer all the best available form s of m u scle w ork. a s w e know , all m u scle w ork is highly specific to the sp ortin g activity of that p articu lar athlete. w h e n discussing rehabilitation the isokinetic ap p aratu s offers y ou a g re a t sp ectru m of reh a­ bilitation variables ab ove pulleys, p ro ­ p riocep tive n e u ro m u scu la r facilita­ tion (p .n .f.) an d n o rm al strength m achines. i h av e w ork ed w ith this equipm ent and h ave found it to be excep tion ally helpful in the acu te rehabilitation p h ase of the p o st­ o p erative patient. p .n .f . is v e ry effec­ tive bu t in m a n y cases the patients are far too stron g for the p h ysiotherapist. u su ally the p h ysio th erap ist is too fatigued to be of a n y effect, an d there­ fore can n o t g iv e the patien t a reason ­ able exercise session, unless the patien t is excep tion ally w eak. this equ ip m en t also offers the athlete d irect v isu al feedback w hich helps to m otivate the patient. a n im p ortan t asp ect of early isokinetic rehabilita­ tion in certain p o st operative co n d i­ tions e.g. k en n ed y l.a .d . re co n stru c­ tion of the an terio r cru ciate ligam ent. in su ch cases the knee joint m u st not be load ed in full extension for a p p ro x i­ m ately 6 m onths. this can be co n ­ trolled e xtrem ely safely for the full rehabilitation p eriod allow in g the p atien t to load the relevan t thigh m u s­ cu latu re w ith ou t d a n g e r of o v e rlo a d ­ ing the reconstruction. a n acu te m edial collateral ligam ent m u st n ot be loaded in full extension either, these athletes can u n d e rg o extensive q u ad ricep s a t­ rop hy. w ith early con trolled stren g th ­ ening y ou can lim it load ing of the involved ligam en t w hile v e ry effec­ tively m aintaining an d even im p rov ­ ing the q u ad ricep s stren g th for early retu rn to play. a n o th er good exam p le is an a cu te ankle sp rain w hich can be actively rehabilitated in n on -w eight b earing doin g inversion and eversion ran ges of m o vem en t, strictly co n trol­ ling the inversion so as n ot to o v erlo ad the healing lateral stru ctu res. in m an y soft tissue injuries it is u nw ise to initially load d am ag ed stru ctu res eccentrically. this can a g g ra v a te the healing p ro cess e.g. m u scle tissue. c o n ce n trics/iso k in e tic loading is p re ­ ferred before p ro gressin g onto eccen ­ tric load ing, w hich 1 a g ree is extrem ely im p ortan t. o nce the athlete is reh a­ bilitated to a painfree full ra n g e of m o v e m e n t he is able to be tested . this helps to m otivate the p atien t into c o ­ op eratin g w ith fu rth er rehabilitation w hich is norm ally a big problem . m any a p atien t is extrem ely cau tiou s and an xio u s in the early stag es of rehabili­ tation. isokinetic ap p a ra tu s helps them to build u p this confidence initially. c onfidence is not easily gained w hen a p atien t is handling a pulley w h ich he d oes n ot control. if he exp eriences p a in h e c a n d ro p th e w eight and dam age him self further. the isokinetic ap p a ra tu s offers a w ell con trolled en viro n m en t for rehabilita­ tion and this can be u sed as a fo u n d a­ tion for stren gth en ing before p ro g re ss­ ing the patien t onto oth er exercise m achin es and m uscle w ork m odali­ ties. the best rehabilitation environm ent for an y athlete is one w hich offers isokinetic, eccen trics, v ariab le isoton­ ics an d pulleys. d iagonal p attern s are also im p ortan t. m ost im p ortan t o f all is th a t the patien t should be intro­ d u ce d back to extensive functional activities, before retu rn in g to his sp ort­ ing activities. y o u rs faithfully, iv a n l evm ran d (b.sc (p h ysioth erap y) (w its) b.sc (m ed. h ons) in sport science (u .c .t ) d ear sir, the n eed in the p rivate secto r to establish a south african r esu scitation c en tre h as been evident for so m e time. initiated by the red c ross (east c ape r egion) and w ith the assistance of dr m ark h arries w ho w as instrum ental in establishing the u k c ouncil, the sou th a frican c en tre has n o w been es­ tablished. the c ou n cil w ou ld like to invite other interested p erson s to join an d becom e involved in the w ork of resco. the c ouncil will p ro m o te uniform ­ ity an d stan d ard isation in c p r tech­ n iq u e s /m e th o d s in all areas ranging from basic to a d v a n ce d life support. a p p lication form s are available from the s ecretary, r esu scitation council of south a frica, p .o .b ox 4 9 2 , p ort eliza­ beth, 6 0 0 0 . y o u rs faithfully, c .a .s cales (m rs.) p p j.a .s trom b eck m b.ch.b. c h airm an . ^ s p o r t s m e d i c i n e . v o l 4. n o 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the athlete and his diet in general mieke faber, rind, sa medical research council. here are m an y superstitions about the v ario u s foods ath ­ letes should eat ( an d avoid ) to im p rove their perform ance. h ow ever, it is know n that the nutritional req u irem en ts of athletes are based on the sam e fundam ental principles that govern the nutrition of h u ­ m an beings in general. it should be kept in m ind that a nutritionally well b alanced diet could aid the athletes p e r­ form ance and m an ipu lation of the diet m ay even im p rove his p erform an ce. g ood e a t­ ing habits entail know ing h ow to com pile the diet from the various foods available. the following guidelines should be kept in m ind: * in a w eight stable p erso n of ideal w eight the en erg y intake should equal the en ergy exp en d itu re. this will re­ sult in the bod y w eight rem aining m ore or less stable. * less than 30% of the en erg y intake should be supplied by fat. s atu rated fat (m ainly anim al fat) should n ot su p p ly m o re than 10% of the total en erg y intake. * betw een 10-15 % of the en erg y should be sup p lied by protein, 1-1,5g p ro ­ te in /k g b od y w eigh t should be suffi­ cient for m o st athletes. * a p p ro x im a te ly 55-58% of the en ergy sh ou ld be su p p lied by carb o h yd rates, m ainly in the form of co m p lex carb o ­ h yd rates. it should be kept in m ind that alth o u g h su g ar is a con cen trated form of en erg y, it d oes not su p p ly any nutrients oth er than en ergy. if m o st of the carb o h yd rates in the diet are supplied b y su g ar, the athlete is a t risk of d evelo p ­ ing vitam in and m in­ eral deficiencies. * provided that a well b a la n c e d d ie t is c o n s u m e d , u n d e r m o st circu m stan ces there is no need for additional v itam in an d m ineral su p ­ plem entation . w hen selecting the food intake, it should be kept in m in d that none of the ord i­ n a ry foods are of special v alu e or con train d icated in athletic p erfo rm an ce. ( f ) letters to the editor (continued from p l6 ) dear sir, applied kinesiology w ith reference to dr. k ro m h ou t's let­ ter in the june 1988 issue elaborating on the m erits of a p p lied k inesiology, i wish to co m m en t as follow s: 1a pplied k inesiology can n o t be re­ ferred to as 'h ig h ly accu ra te '. the basis of this sy stem is the d iagn osis of p hysiological im balance by m anual estim ation of the stren g th of certain indicator m uscles. t h ou gh this m ay suggest som e im balance, a cc u ra cy can be achieved only by m ean s of suitable in stru m en tatio n such as a d y n a m o m e ­ ter, force plate or strain guage. m o re­ o ver, m an u al isom etric testing can p ro d u ce m easurable fatigue in the m u scles of the p atien t and the p ra cti­ tioner, so the test p ro to co l itself can in tro d u ce im balance! 2. the basis of the system need s to be carefully evaluated, since perfect m uscle b alan ce is u n p hysiological. the h u ­ m an b od y is asy m m etric in stru ctu re and function, even in elite athletes. in b iom echan ical research i h ave p e r­ form ed on w eightlifters, not a single subject has d isp layed sy m m e try of m u scle stren gth , y et each one has been th o ro u gh ly healthy. 3. d r.k rom h ou t points o ut co rrectly that an th ro p om etric or radiological techniques m easu re stru ctu ral differ­ ences u n related to functional im bal­ ance. both ch iro p ra cto rs and o rth o ­ p aed ic specialists should m ake use of ap p a ra tu s w hich can assess the func­ tional ch aracteristics of the sp o rtsm an d u rin g actual sp o rtin g m ovem en ts. 4. m uscle b alan ce is altered both after stren u ou s exercise o r p rolon ged in ac­ tivity, a situ ation w hich can introd uce seriou s u n certain ty into applied kine siological testing. a pplied k inesiology requires m ore extensive stu d y and better ap p lica­ tion. y o u rs faithfully, m.c.siff. ph.d. c om m u n ication studies division, u n iversity of the w itw atersran d . s p o r t g e n e e s k u n d e v o l 4. n r / r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ultraman voltaren ultraman 1989 emulgel round-up for the second year in succession, nic bester walked away with the top laurels in the 1 9 8 8 / 8 9 voltaren emulgel ultraman competition. bester's winnings totalled r16 000 and other medalists shared r14 000. there were cash prizes of r2 000 for the first ultraman to finish each event. for a time it looked as though danny biggs might maintain his early lead as he was still well ahead after the μ id mar mile and the two oceans. an exciting contest was settled on the last event of the ultraman calendar — the comrades marathon. bester's fourth place enabled him to wipe out biggs' 6 point lead and win by a further 8 points. a p p l i c a t i o n f o r research grant to promote knowledge about the role of sugar in health and nutrition, the south african sugar association looks to the scientific community for reliable and up-to-date information. as part of this process, it supports scientific research projects designed to clarify issues which arise in this public terrain the sugar association acts on the recommendations of a research adviser and advisory panel. priorities for research funding by the association are: 1. physical work, exercise or sport in relation to diet. 2. obesity and the comparative role of different dietary factors and forms of exercise. 3. hyperlipidaemias in relation to diet. 4. causes of dental caries and periodontal disease. 5. causes of diabetes mellitus and its management. 6. dietary influences on brain function. proposals in any one of these priority fields will be given consideration. the research grants are awarded on a 2 yearly basis. continuation of the grant for the second year of study is dependent on progress made, as assessed by the advisory panel from a report submitted for this purpose. instructions or proposal preparations: in order to allow for a proper evaluation of proposals by reviewers, the following items should be included: 1. one page abstract of the proposed project (200-word maximum). 2. short description of background for proposed research. 3. succinct statement of project objectives. 4. short description of methods to be used in pursuing objectives. 5. human subject assurance, if applicable. 6. curriculum vitae and list of full-length publications over last six years. 7. detailed budget (to include the proposed budget for the first and second years of study). note: no funds are provided for major equipment (unit cost greater than r2 000) or travel costs. the deadline for proposals to be submitted is 15 november 1989. application forms are available from and, when completed, should be returned to: the nutritionist, the south african sugar association po box 374 durban 4000 tel. (031)3056161 sugar association sports medicine. vol 4. no 1 the women's race was totally dominated by sally bantock. t h i s former provincial hockey player scored 375 points, no less than 200 points ahead of the second lady, sandra eardley. sally was placed 14th o v e r a l l in the voltaren emulgel ultraman competition. the veterans was a close run thing with wilmot finishing on 442, less than 20 points ahead winners all! pictured above are the overall of max botha ivinners in the three ultraman categories. nic bester (men), sally bantock (women) and wilmot (jf (veterans) picture courtesy of sports international cricket injuries (. . . continued from page 5) (text continues on following page) acute and chronic injuries sustained in first-class cricket during batting (n=81) phalyngeal fractures (25) muscle tears (1) — rib fractures/contusions (z lower arm contusion (4) back strains (3) groin strains (2) quadriceps tears (2) hamstring tears (2) knee ligament tears (2) calf strains (2) ~~~ ankle ligament tears (2) foot fractures/contusions (4) during bowling (n=64) elbow strains (1) shoulder strains (4) pinched nerve (6) back strains (22) abdominal muscle strains (3) groin strains (8) quadriceps tears (2) hamstring tears (3, knee ligament tears (2) ankle ligament tears (6) foot stress fractures/ contusions (4) during training and warming up (n=ll) facial lacerations (3) back strains (2) phalangeal fractures (1) groin strains (1) hamstring tears (1) ankle ligament tears (1 foot contusions (2) facial laceration (1) elbow strains (2) shoulder strains (5! phalangeal fractures (19! groin strains (2) hamstring tears (z knee liment tears a n k l e ^ l i g ment tea: foot contu" sions (1) f r during fielding (n=37) total injuries sustained n=193 sportgeneeskunde vol 4. nr 1 φ cricket injuries t a b l e i: s e r i o u s a n d l e s s s e r i o u s i n j u r i e s s u s t a i n e d w h i l e p l a y i n g c r i c k e t s e r io u s in ju r ie s less se r io u s bat b o w l field o t h e r t o t a l 7< t o ta l ( lead , n eck and facial in juries 31 3 1 3 38 20 12 10 u p p er limb injuries 30 5 2 6 1 b2 32 31 43 back and trunk injuries 5 28 2 3 5 18 10 14 l o w er lim b injuries 15 28 10 5 58 30 20 27 t otal injuries 8j 64 37 11 193 73 7, 42 33 19 b 100 100 b o d y has to a b s o r b a vertical force 4,1 ti m es gre ate r tha n the bo d y w ei gh t and a ho rizontal d ec el er a tio n force 1,6 times his b o d y weight. ,4j5 t h e s e authors found that these im p act forces, in a s so ci ation w ith the lateral flexion, ex ten si on , ro tat ion and c o m ­ p re ssion of the vertebral c o lu m n d u r ­ ing delivery, to be the re aso n for the increas e in ba ck injuries in fast b o w l ­ ers. a front-on a ct ion woul d m a k e the b o w le r m o re su sc ep ti b le to injuries than o n e w h o b o w ls with a side-on act ion all o w in g him to s u m m a te his b o d y forces m o r e efficiently thus p r o ­ ducin g m a x im a l ball veloci ty with m in im a l strain to his b o d y s t r u c ­ tures l6. in a st ud y on the fitness of cric ke ter s 17 it was found that cric ke ters had an a b o v e a v er a ge level of fitness, with the ex c ep tio n of b a c k and h a m stri n g flexi­ bility. no si gn if ic an t dif fer ences in the v a ri ou s c o m p o n e n t s of fitness w ere found w hen b a ts m en , b ow le rs , all r o un d e rs and w ic ke tke ep e rs were co m p a r ed . t h e b ow le rs , w h o need to po ss ess stren gth in the hips, ba ck and s h o uld er s, sh o w ed the lowest score for s tre ngth and m u s cu la r e n d u r a n ce o f the a rm s and s h o u l d e r s . 15 th is lack o f s tre ngth and flexibility in the back and h am st ri n g s, co u ld be o n e of the m ai n ca u se s of bac k injuries in b o w l ­ ers. by follo w ing a s pe ci alized train­ ing p r o g r a m m e aim ed at d ev e lo p in g an a p p r o p r ia te level of fitness specific to the task to be p e r fo rm e d in a match, unnecessary injuries could b e a v o i d e d . lv c o n c l u s io n s t h e f ollow in g r e c o m m e n d a t io n s are m a d e in an a tt em p t to p re ve n t serious injuries taking place, as well as to try to redu ce the n o r m a l injuries a s s o ci­ ated with field sports: * c o n s id era tio n m a y h a v e to be m a d e to m a k e the w ea ri n g of helmets, pa rt ic ul ar ly those with a full visor, c o m p u l s o r y , * b a ts m en need to practise on pitches that ar e si m ilar to those they are likely to e n c o u n t e r in a match, * b o w le rs need to d e v e lo p leg, back and tr unk s tre ngth and flexibility, * b o w le rs should e n su re that the boots worn are ab le to a b s o r b the tr e m e n ­ d o us forces g en er a te d at front-foot im p ac t in the d el ivery stride, * cap tain s and c o a c h es sh o uld avoid o v e r b o w l i n g their fast bow le rs, pa rt ic ula rl y at the b eg in n in g of the s ea s on , * b o w le r s and c o a c h e s need to place special em p h a s is on te ch n iqu e in an a tt e m p t to d e v e lo p a s ide-on b o w l ­ ing action, * all cr ic kete r s need to fol low p er­ so nalized training p r o g ra m m e s ca ter in g for their sp ecific nee d s and their s p eci alis ati on in the team. t h e g am e o f crick e t is d e m a n d in g m o re p h y sica l o u tp u t from the p la y ­ ers w ho ca n n o t affo rd to su ffe r u n ­ n ecessary inju ries, p articu larly at vital sta g e s of the seaso n . a t all levels the a stu te coach and p lay er m u st e n su re th at u n n e ce ssa ry in ju rie s are n ot a c o n trib u tin g facto r in a te a m 's failu re to reach its p o ten tial. rei-erlnces i w e ig h tm a n , d an d b ro w n e , r.c. in ju rie s in e le v e n '•elected spor(>. b ritish jo u rn a l o f s p o r ts m e d ic in e , 1971, 2 , 27. 2. t e m p le , r. c ric k et in ju rie s: fast p itc h e s c h a n g e th e g e n lle m a n 's s p o r t , t h e p h v s ic ia n a m .1 s p o rts m e d ic in e , 1 9 8 2 .1 0 (6 ) ism 92. 3 p a y n e , w .r ., i lo v , g ., l a u s se n , s.p . an d c a rls o n j.s. w h a t res e a rc h te lls th e c ric k e t c o a c h . s p o r ts c o a c h , 1487, 10(4) 17-22. 4. o g ilv ie , f m . o n o n e ol th e res u lts ol’ c o n c u s s io n in ju rie s o f th e e v e ( " h o l e s " <il th e m a c u la ) t r a n s a p lith a lm o l s o c u .k . f a l l ) ,2 0 ,2 0 2 -2 29 3 d 'a m b ro in , a. t ra u m a tic m o n o c u la r c h ro n ic g la u c o m a , t r a n s o p h th a lm o l so e. a u st., 194 5 , 5 ,1 1 6 1 2 0 . 6 . l ille w o o d , k .r. blu n t o c u la r tra u m a a n d h v p h a e m a , a u s tra lia n jo u r n a l o l o p h th a lm o l, 1982, 10, 2b3-2hh. 7 jo n e s , n .p . a n d t u lin , a b s e v e re e v e in ju rie s in c r ic k e t, b ritish jo u r n a l ot s p o r ts m ed ic in e , 1986. 2 0 ,(4 ), 178-174 8. w illia m s . i.g .p . jo in t in ju rie s, in-1 c o h e n , c .k b eaten and d m itc h e ll (e d ito rs ). t h e s o u th a frican t e x tb o o k o l sp orl> m e d ic in e , u n iv e r s ity o f w it u a t e r s r a n d , lo h a n n e s b u r g 1979. 9. c o r r i g a n , a .b . c ric k e t in ju rie s, a u s tr a lia n f am ilv i mu sic ia n 1984, !> (8 ), 53s-5t>2. it' c o k o n , j.h .c . an d a rm o u r, w .j. s p o r ts in ju rie s an d th eir tre a tm e n t, s ta n lev paul a n d c o, l o n d o n , 197^. 1 i. c le m e n ts , m .r . an d h a m ilto n d .v . p n e u m o m e d ia s tin u m as a c o m p lic a tio n o t fast b o w l in i; in c r ic k e t. p o s tg ra d u a te m ed ic a l jo u r n a l, 1982, 5 8 , 4 35. 12. f o s te r, d ., e llio tt, b. g ra v , s ., an d h er/ b erg , l. g u id e lin e s fo r th e fast b o w le r, s p o r ts c o a c h . 1984. 7(4> 4 7 -4 8 13 . s tr e tc h . r. a. a n th ro p o m e tr ic p r o file o l lir s l-c la s s c r ic k e te r s , s .a . jo u rn a l lor r e s e a rc h in s p o r t, p h v sica ) e d u c a tio n a n d r e c r e a t io n , 1987, 1 0 (1 ), 6 3 -7 6 . 14. e llio tt, b .c . a n d f o s te r, d .h . a b io m e c h a m c a l a n a ly s is ol th e iro n l-o n an d s id e o n fa st b o w lin g te c h n iq u e s . jo u rn a l ol h u m a n m o v e m e n t s tu d ie s , 1984, 10, 83 -9 4 15. e llio tt, b .c . f o s te r, d .h . an d g r a v , s b io m e c lia n ic a l an d p h y s ica l f a c t o r s in f lu e n c in g fast b o w lin g , a u s tr a lia n j o u r ­ nal o f s c ie n c e a n d m ed ic in e in s p o rt. 1986, 1 8 ( 1 ) 16-21. 16. f o s te r, d. in ju ry a n d its p re v e n tio n in fast b o w lin g , p ro c e e d m g s o f a .s .m .f . a n n u a l sc ie n ti tic c o n fe re n c e , p erth a u s tr a lia , 1984. (7 . s tr e tc h , r.a . an d b u y s, f.|. p h v sica l f itn es s p ro file o t so u th a frica n u n iv e rs itie s c ric k e te rs , u n p u b lish ed p a p e r, 1987. r e d d ic k , t plav c ric k et th e right w a y . s e v e n s e a s p u b lic a tio n s c a p e t o w n , 1979. d a v is, k. t ra in in g p rin cip le s r ela te d to c ric k e t, c o a c h , 1984, 8 (3 ), 2 3 -2 5 sport* $ s p o r t s m e d ic in e . v o l 4. n o i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) review 1 sajsm vol. 31 no. 1 2019 creative commons attribution 4.0 (cc by 4.0) international license a review of the biomechanical determinants of rugby scrummaging performance a green,1,2 phd (physiology); y coopoo,1 dphil (biokinetics), facsm; j tee,3,4 phd (sports science), cscs; w mckinon,2 phd (physiology) 1 department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa 2 movement physiology laboratory, school of physiology, faculty of health sciences, university of the witwatersrand, south africa 3 department of sport studies, faculty of applied sciences, durban university of technology, south africa 4 carnegie applied rugby research (carr) centre, institute for sport, physical activity and leisure, carnegie school of sport, leeds beckett university, leeds, united kingdom corresponding author: a green (andrewcraiggreen@gmail.com) in rugby union, a scrum is awarded when a team knocks-on the ball, or to restart play in situations where the ball has become unplayable.[1] a scrum is a contest between eight players (forwards) from opposing sides who are bound together and push in a coordinated strength contest for possession of the ball. scrums are composed of eight players from opposing sides interlocked in a distinctive formation. players are arranged into three rows: front row (loose-head prop, hooker and tight-head prop); second row (two locks); and the back row (two flanks and an eighth man). props bind to the hooker by gripping tightly onto the waistband, while the hooker will clasp the props around the shoulders by gripping onto the jersey below the shoulder blades. the second row links together shoulder to shoulder binding to the front row by lodging their heads into the gap between the hips of adjoining prop and hooker. back row players will bind onto the second row players. specifically, flanks will attach themselves to the locks and place a shoulder to push onto the prop on their side of the scrum (either looseor tight-head). the eighthman will bind between the hips of the second row players and maintain a forward push. a scrum will commence when the team has assumed their formation and front row players from the opposing sides interlock in a forceful, yet controlled manner. typical scrum durations are approximately 3 ± 1.4 seconds[2], with 20-30 scrums occurring per game.[2-4] effective scrummaging is a key determinant of team performance. scrum dominance provides a platform for launching attacking play and allows for the disruption of an opponent’s attacking play. as a result of safety concerns, scrumming is highly regulated[5] and frequently penalised by referees.[6] teams with dominant scrums are awarded more scrum-related penalties[7], allowing them the opportunity to score points and gain territory. historically, scrum involvement resulted in a number of catastrophic neck and spinal injuries.[5,8] in response, world rugby has made changes to the rules governing scrums and particularly, the methods of front row engagement.[9,10] while these changes have been effective,[8] scrum laws continue to evolve. coaches need to have a clear understanding of the determinants of effective scrumming to allow them to coach effectually and adapt these appropriately in response to the frequent rule changes. the purpose of this brief review is to identify, explain and expand on the literature focussing on scrummaging force generation in order to illustrate the current scientific understanding of scrummaging performance. the intention of this review is to better isolate key performance factors which may facilitate future research and produce more successful yet safer scrummaging performance training programmes. kinetics scrum kinetics have been used as the major objective scientific measure of scrummaging performance. various methods have been employed to quantify this which include: instrumented scrum machines[11-16], force platforms[17], and shoulder mounted pressure transducers.[18-20] background: the scrum is a physical contest unique to the game of rugby union, important for determining match outcomes. objective: this review will describe the current understanding of the kinetic and kinematic determinants of successful scrum performance to support coaching interventions and inform on future research. methods: literature review. results: individual and combined scrumming forces increase with playing level but there is no concurrent increase in body mass or player strength. there is very little variation in individual kinematics between individuals and across levels of play, suggesting that there are limited possible techniques for successful scrummaging. live scrum contests are dynamic and require constant adjustments to body positions in response to increased compressive force and exaggerated lateral and vertical force components. skilled performers are able to exert high levels of horizontal force while maintaining effective body positions within this dynamic environment. conclusion: success in scrummaging depends on the optimisation of joint angles and force production at the individual level, and the coordination of effort at a team level. the analysis presented here demonstrates that producing large scrum-specific forces and achieving the optimal ‘body shape’ are essential for successful scrum performance. keywords: scrummage, force, kinematics, kinetics, muscular strength s afr j sports med 2019;31:1-8. doi: 10.17159/2078-516x/2019/v31i1a7521 mailto:andrewcraiggreen@gmail.com http://dx.doi.org/10.17159/2078-516x/2019/v31i1a7521 https://orcid.org/0000-0001-5148-1607 https://orcid.org/0000-0002-7275-2928 https://orcid.org/0000-0002-0275-0070 https://orcid.org/0000-0002-4673-8145 review sajsm vol. 31 no. 1 2019 2 force components the force exerted in the scrum is composed of compressive, lateral and vertical forces.[10,16,21,22] the lateral forces have been found to be directed towards the tighthead prop (right)[10] and attributed to the wheeling of the scrum.[16,20] vertical or shear force has, in turn, been associated with scrum collapses and front row players coming out of formation.[10,19,20] even though lateral and vertical forces contribute to scrum contest outcomes, the compressive force (i.e. forward pushing force) is of most interest to investigators and coaches due to its obvious performance implications. the compressive, vertical and lateral forces present during scrumming are the result of the kinetic capabilities of the team’s scrum as a unit, which are comprised of the distinct individual kinetic capabilities of each player. however, combined pack kinetics do not equal the sum of individual kinetics due to the compression of soft tissue and the cancellation of interactions between players within the scrum pack.[14,15] individual force contributions scrum contests are usually won by packs with larger combined compressive forces.[23] assessments of team scrummaging have identified the contribution of various playing positions in terms of the total scrummaging forces. interestingly, the front rows contribute the most force, namely between 42% 46%, and locks generate between 21% 37%, respectively. on the other hand, the loose forwards contribute the least of between 21% and 30% of the total scrummaging force.[14,24] although the different playing positions in the scrum contribute varying magnitudes of force, they may tend to use the directional components of these forces to varying degrees. for example, in addition to the 21% 30% contribution to total scrum force, loose forwards also assist the tight five players by improving scrum stability.[14,16,20] du toit et al.[14] showed that the largest lateral force application angles were produced by tight-head flankers. therefore, flankers act as a wedge which assists in developing larger compressive forces and maintaining the forward direction of their props, which may be displaced by the second row’s (locks) force application angles.[14,25] force magnitudes measured from individual studies vary greatly (table 1). variations are due to measurements at different points in time, levels of playing proficiency of the study’s participants (both in terms of playing position and level of competition) and surfaces. despite this, the individual peak force of scrummaging may exceed 3000 n in idealised indoor settings, yet it is slightly lower than 2500 n on natural turf (although the latter have only been assessed in sub-elite players). peak forces may be a result of the engagement force, which is significantly larger than the sustained force.[10,18,21,22] thus a peak force may not truly reflect an individual’s ability to exert a similar magnitude during the sustain phase of the game. new scrum laws have had a considerable effect on scrummaging kinetics where bind and set phases attempt to make the engagement safer by reducing the collision between table 1. individual scrummaging force magnitudes, playing levels and ground compositions from recent publications study individual force magnitude (n) body mass (kg) playing level measurement of maximal force ground composition quarrie and wilson [15] 1370 ± 280 96.9 ± 9.8 premier club peak synthetic matting hot et al. [26] 1466 ± 244 96.9 ± 10.1 club elite ns ns wu et al. [13] 1171 ± 277* 85.5 ± 9.61 national peak indoor sharp et al. [17] 4493 ± 151 112.1 ± 6.5 professional peak synthetic matting sharp et al. [17] 3091 ± 653 101.4 ± 9.3 senior amateur peak synthetic matting sharp et al. [17] 3362 ± 788 99.1 ± 6.0 junior amateur peak synthetic matting mensaert et al. [27] 3205 ± 3093 ns junior amateur peak indoor mensaert et al. [27] 3076 ± 1014 ns senior amateur peak indoor mensaert et al. [27] 5010 ± 1195 ns professional peak indoor cazzola et al. [19] 2800 ± ns 102.4 ± 15.0 university 1st xv peak indoor morel et al. [28] 1609 ± ns 90.9 ± 9.8 elite u-23 mean sustained over 5 seconds synthetic track green et al. [11] 2254 ± 649 101.0 ± 14.1 club amateur/university peak natural turf morel and hautier [29] 1741 ± 207 103.3 ± 11.8 elite u-23 peak during engagement phase artificial turf green et al. [23] 2274 ± 636 99.0 ± 18.2 club amateur/university peak natural turf green et al. [30] 2458 ± 455 103.0 ± 12.1 club amateur/university peak natural turf green et al. [31] 1720 ± 363 106.2 ± 13.3 university 1st xv peak indoor bayne and kat [32] 2290 ± 410 100.7 ± 15.0 club amateur/university mean sustained resultant force over 9.5 seconds natural turf sprinting blocks data are expressed as mean ± sd ns, not specified within text; n, newton; * calculated from percentage of average body mass and converted to force. review 3 sajsm vol. 31 no. 1 2019 the front rows.[6,9] additionally, the new laws prevent teams from pushing before the ball is fed into the scrum. however, from a kinetic perspective, this procedure complicates the contest since an initial low-level contest is introduced prior to the dynamic one. this means that the scrum must remain steady and the packs must exert a certain level of force to keep the scrum stationary. once the ball has been fed into the scrum, teams can actively compete for the ball, which should result in a second force peak. therefore, a team that can sustain a larger force magnitude during the steady state and actively generate a ‘second shove’ once the ball is fed, may achieve better scrum outcomes than the previous isolated engagement or sustained forces under the older rules. there are numerous difficulties comparing combined pack scrummaging forces across multiple studies. the first issue is the change in scrummaging rules, which have reduced the engagement force.[18] however, data presented by preatoni et al.[10], and cazzola et al.[19] illustrate that the sustained compressive force remains unchanged regardless of the engagement procedure. therefore, table 2 reports the sustained compressive forces for pack scrummaging. a second concern is the devices used to measure the compressive force. most studies have used static instrumented scrum machines; however, du toit et al.[20] and cazzola et al.[19] used shoulder mounted pressure sensitive pads during live scrums. based on these various collection methods, a large range of force values are reported in this review. specifically, the large discrepancies between data reported by preatoni et al.[10] and cazzola et al.[19] may be indicative of the methodologies employed. static instrumented scrum machines are less likely to overestimate forces due to their rigidity. however, while shoulder mounted force sensors may underestimate force magnitudes due to tissue artefacts between the opposing front rows, they give a better description of live scrum contests.[18] front row binding involves the interlocking of two rows of three players each where their heads will be positioned between two opposing players. due to the binding offset, loose-head props will only have one contact point (the shoulder of their opposing tight head prop) which allows a greater range of motion and the possibility of generating larger lateral and vertical forces. additionally, front rows experience a larger force on their shoulders when scrummaging as a pack compared to individually, which can be attributed to the summation of force from the locks and loose forwards respectively.[20] despite variations in rules and force measurement techniques, scrummaging force magnitude has been found to increase with the playing level[10,33], which may result from increasing player mass and strength. however, no correlation between either body mass or strength measures and maximal horizontal scrummaging forces in professional players exists.[17] players of similar body mass and strength must therefore be using different scrummaging techniques to achieve their maximal scrummaging forces.[10,17] these technical parameters may be based on movement (kinematic) strategies[10,34] or achieved through the coordination of exerted forces within the scrum.[20] kinematics features of an ideal scrum position were introduced by milburn[24] who suggested that the head, including the neck, trunk and legs all be aligned parallel to the direction of the intended force. additionally, it was suggested that a greater angle (sagittal plane view) between the trunk and legs (hip angle) results in a larger force.[24] most studies have, however, been descriptive in nature. the following section summarises the findings of these studies, with a kinematic description of the scrum sequence spanning the preparation, engagement, steady state (pre-ball feed) and contest (post-ball feed) phases. preparation phase the scrum engagement sequence begins with the players in a crouched position. during the preparation phase, prior to the two front rows engaging, players bind to their opponents by gripping onto their jerseys. front row players are instructed to have their shoulders above their hips (when viewed in the sagittal plane) to prevent the scrums from collapsing resulting in their trunks being slightly above the parallel relative to the ground.[19,24,34] in this preparation phase, the players have their feet firmly on the ground with a large degree of flexion at the hips and knees. wider foot stances may influence the generation of scrummaging forces.[30] foot orientation may be slightly everted to allow for a larger ground contact area relative to the direction of the imparted force. most forwards will adopt a parallel foot stance on set-up, prior to the scrum contest; however, a minor offset between the feet may be present.[13,32] of importance is that sayers[34] showed while starting positions may differ, body positions upon engagement are similar. therefore, the preparation phase of scrummaging may only be a result of player preference and their ability to maintain balance prior to scrum engagement.[17] engagement phase on the call of “set”, front row players rapidly extend their hips and knees[34] and in a controlled manner and make impact with their opponents. it is during the engagement phase that the generation of maximal compression force is usually exerted.[19,21] combined vertical force components are initially directed downwards but continually shifts upwards as scrummaging duration continues.[10] the kinetics of the scrum therefore, closely represent the kinematic changes which occur.[30] du toit et al.[14] stated that the front row requires vertical stability before being able to apply force. furthermore, du toit et al.[14] suggested that the front row make a deliberate effort to scrum higher up to prevent the scrum from potentially collapsing. it can be presumed that starting at a lower, more flexed position could be beneficial as the player could produce greater upward force through the extension of their hips and knees.[30] the sustained force phase follows the engagement phase.[10] forces during the sustained phase fluctuate around a constant magnitude which is lower than the force produced during the engagement phase.[10] of importance is that the sustained force review sajsm vol. 31 no. 1 2019 4 phase as measured on scrummaging ergometers may not reflect the dynamic nature of a live scrum contest. in line with the most recent definitions of the law, the sustained phase is divided into steady-state (during which force magnitudes are maintained) and the contest phase (once the ball enters the scrum tunnel and players are required to strike or contest for the ball). the latter phase is yet to be replicated on a scrum machine or kinematically evaluated during live scrummaging. the steady state phase (pre-ball feed) the steady state phase, which occurs on immovable scrummaging machines, reflects the sustained force period with the players remaining in a largely isometric position. during the sustained phase, the lower limbs exhibit a large degree of extension[13,15,30,31,34], and the trunk will gradually rise above the horizontal position.[18,19] this movement and body position may result in players ‘overextending’ which could cause the scrum to collapse. statistically significant relationships have been presented between the extensions of the hip (r=-0.47), knee (r=-0.51) and the ankle (r=-0.70) and the individual scrummaging forces.[13] bayne and kat[32] inferred correlations for ankle dorsiflexion (r=0.12), trunk extension (r= 0.32) knee (r= -0.63) and hip flexions (r= -0.74) angles and the compression force. other researchers have failed to show relationships between kinematics and scrummaging performance.[15,30] collectively, these findings do not provide conclusive relationships between force development and scrummaging body positions. methodological differences, players’ skill levels and ecological constraints may further compound the difficulties in finding distinct movement patterns related to scrummaging force development. table 3 collates joint angles from various individual scrummaging assessments at maximal sustained force. the similarities in the individual kinematics reported in this review suggest that there are limited techniques to scrummaging. further evidence suggests that proficient players adopt a similar body position over the scrum’s duration[34] with little axial skeleton movement variability.[35] thus it is possible that the body position optimal for force production is fundamentally safe and effective.[8] finally, an effective scrummaging position may require obtaining individualised optimal length-tension relationships in the primary muscles rather than attaining particular joint angles. further research into the relative contributions of different muscles, muscle coordination and individualised force-tension relationships of major muscle groups to the overall force generation may deepen the understanding of muscle force production during scrummaging. with regard to the effects of feet positioning adopted during the preparations phase, no significant difference in the exerted forces were reported irrespective of the feet’s positions.[13] however, a double peak force pattern is exhibited in the crossfeet position, compared to the single peak in the parallel feet position. an offset foot stance could result in larger lateral forces on the side of the lead leg diminishing the total compressive force of the scrum[32] and may cause the scrum to wheel. additionally, these increased lateral forces may cause excessive spinal rotation experienced by the individual players, as the hip may act as a pivot around which the axial rotation of the trunk can occur. the contest phase (post-ball feed) the findings above focussed on static body positions during individual player scrummaging. however, the scrum is dynamic and requires adjustments in body positions resulting table 2. pack playing levels, weights and sustained compressive forces during team scrummaging study playing level pack weight (n) sustained compressive force (n) milburn [16] high school 5588 3370 university 6726 4160 quarrie and wilson [15] premier rugby 7570 ± 350 7234 ± 726* du toit et al. [14] high school ns 6848 ± 1140 du toit et al. [20] high school 6406 ± 235 6146 ± 1337 preatoni et al. [10] (crouch touch set call) school 6685 ± 637 4900 ± 1300 women 6326 ± 257 4800 ± 500 academy 7771 ± 197 5900 ± 800 community 8262 ± 325 5800 ± 400 elite 8523 ± 143 8000 ± 700 international 8749 ± 165 8300 ± 1000 cazzola et al. [19] (crouch touch set call) elite 8378 ± 275 3800 ± 1200 cazzola et al. [19] (prebind) elite 8379 ± 275 3800 ± 1400 data are expressed as mean ± sd ns, not specified within text; n, newton; *authors state that packs were able to exert 66% of the peak impact force during active scrummaging (sustained force) table 3. kinematics of individual scrummaging attempts at maximal sustained force study sample size hip (°) knee (°) ankle (°) quarrie and wilson [16] 56 123 ± 24 107 ± 13 78 ± 11 wu et al. [13]* 10 121 ± 7 101 ± 18 62 ± 16 mensaert et al. [27] 28 162 ± 73 101 ± 40 85 ± 25 green et al. [30] 25 114 ± 17 144 ± 16 73 ± 16 green et al. [31] 12 103 ± 33 124 ± 16 89 ± 18 bayne and kat [32]* 29 126 ± 17 129 ± 14 89 ± 7 data are expressed as mean ± sd *feet in the parallel position. hip and knee angles have been adjusted to report the degree of extension (full extension denoted by 180°) review 5 sajsm vol. 31 no. 1 2019 from the scrum contest. measuring kinetics during live scrum contests is difficult, as the motion is dynamic, and the scrum cannot realistically be contested against an immovable object. similar to scrum machine kinetics, shoulder mounted force sensitive devices recorded significantly lower sustained forces during a live scrum in comparison to the live engagement.[20] however, greater fluctuations in the force may exist. during a scrum contest, players attempt to step forward. this will produce surges in the compressive force and exaggerate the lateral and vertical force components.[32] further confounding the issue is when a player strikes for the ball as stipulated by the law, they will remove one foot from the ground. this action will cause a reduction in the force magnitude. therefore, in order to maintain the opposing pack force, the scrum pack will have to increase their individual force contributions. this highlights another gap in the understanding of scrummaging performance. scrum contest complications kinematic analysis of scrummaging poses numerous difficulties. from a data collection perspective, it is easier to collect scrum kinematics on individual players compared to an entire pack. one solution may be to use wearable inertial sensors[36] or modern video technology that does not require surface markers. kinematic analysis is limited by its predominant use of scrummaging force as a performance index. the analysis is further limited by testing against an immovable object where an individual player can only perform isometric exertions. furthermore, contest phases cannot be emulated against an immovable ergometer. while this method is ultimately the gold standard for measuring scrummaging forces, more representative methods are required to measure pack power, forces and velocities. despite these shortcomings, the measurement of technical variables identified through kinematic analysis may assist in training drills and aid in the development of good techniques.[35] relationships between the generation of scrummaging forces and specific body (or joint) positions may, however, be difficult to reveal. it is possible that the ability of the muscles to generate torque around these joints may provide additional insight into force generation and performance in the scrum. electromyography the generation of scrummaging force during the engagement sequence is a result of muscular contraction. the majority of muscles investigated in scrummaging studies are predominately those acting on the back, hips, knees and ankles.[17,37-39] as scrummaging is a measure of strength, standardised amplitudes should be related to its performance. however, sharp et al.[17] reported no significant correlations between emg activation levels and scrummaging forces. a possible reason for this lack of relationship could be as a result of the players adopting similar positions and reduced movement, and emg variability during machine scrummaging.[37,38] additionally, stronger players may require less muscle activation to produce similar force.[37] the activation patterns of muscle prior to and during the engagement sequence may reveal important muscular contributions to force generation. the following section briefly identifies maximal activations at specific time-points before the nature of muscle activity over the entire scrum effort duration is described. prior to scrum engagement, the gastrocnemius muscle is largely activated and the vastus lateralis reaches maximal activation, as the knees are rapidly extended.[17,37] back musculature, such as the erector spinae, are largely activated in the preparation phase.[17,38,39] the large muscle activation of the erector spinae sequence can be attributed to the crouched position of the player prior to engagement.[17,39] cazzola et al.[39] suggested that the muscles of the back and neck are primed prior to scrum engagement which could increase joint stiffness of the back and neck. although the increased joint stiffness may adequately stabilise the trunk to assist in the transmission of forces, it may be insufficient to prevent injury. this premise is supported by the highly active erector spinae group during sustained force scrummaging.[17,38,39] assessment of the proximal muscles, particularly those of the back and the abdomen, reveal that the abdominal muscles are not significantly activated[38] over the entire duration. additionally, there is minimal activation of the biceps femoris over the entire scrummaging sequence compared to the rectus femoris and vastus lateralis respectively.[17,38] more distally, the gastrocnemius experiences large activation patterns throughout the scrummaging sequence.[38] an electromyographical assessment obtained during machine scrummaging is not representative of those obtained during live scrums, even though kinetics and kinematic parameters are closely related.[38,39] the dynamic nature of live scrummaging requires more reactive muscle activity. before being able to effectively apply force, the front row needs to establish stability in order to allow the forces generated by the rest of their pack to be effectively transmitted through the scrum onto their opponents. this is confirmed by large erector spinae muscle activity of front row players reported during live scrums.[39] muscular strength and power by definition, muscular strength is the ability to exert force on an external object[40], and therefore strength is essential for scrum performance. scrum forces and player strength increase at the higher levels of the game.[41,42] despite this, so far researchers have failed to demonstrate meaningful relationships between strength measures and scrum force production. logically, the largely isometric action of scrum contest suggests that multi-joint isometric strength measurements would be the best indicators of individual scrum force production. however, quarrie and wilson[15] failed to show a relationship between scrum force and strength in a modified isometric mid-thigh pull. similarly, no relationship has been demonstrated between vertical jump heights and scrummaging force production.[15,30,43,44] however, quarrie and wilson[15] reported weak relationships (r= 0.39-0.41) between individual scrum force and maximal isokinetic knee extension torque at two velocities, while sharp et al.[17] showed no difference in isokinetic tests across playing levels. individual review sajsm vol. 31 no. 1 2019 6 scrummaging force is a strength measure, but meaningful associations with other more traditional strength measures have yet to be clearly established. combined pack mass, strength and power on a population level, body mass and strength are closely related.[45] therefore, it is not surprising that researchers have shown significant relationships between scrum force and combined pack mass.[10,13-16,20,24,30] in the only study to have considered a combined power metric, green et al.[23] demonstrated that winning scrums also had significantly higher combined vertical jump heights. however, du toit et al.[20] reported that while a significant relationship exists between pack mass and combined engagement force, no relationship exists between sustained scrummaging force and pack mass. in this case, fat mass may be a confounder. the reason for this being that while additional fat mass may contribute to engagement momentum, it cannot assist in generating any sustained scrummaging force. additionally, preatoni et al.[10] reported that increases in the compressive force magnitudes in various playing levels were not dependent on pack mass. finally, green et al.[23] reported no association between combined pack mass and the outcome of numerous scrum contests. therefore, it is likely that team scrum performance results from the force production, and technique and timing capabilities of the players rather than combined player mass.[10,15,20,24] however, at an age-group level or non-elite level, a difference in mass may be the determining factor to scrum success. the role of fatigue scrum performance appears to be largely unaffected by the fatigue levels of the players. scrum force production has been shown to be reduced after repeated scrum efforts interspersed by 20 second rest periods[28] but was unchanged when the rest periods were increased to 30 seconds[29], following a rugbyspecific fatigue intervention[31], and repeated sprint activity.[28,46] similarly, scrum kinematics were also unaffected by fatigue.[31] two explanations for this are that fatigue interventions employed in research have been insufficient to induce specific fatigue, or that rugby players develop the ability to maintain a competitive scrummaging force and body positioning under fatigue conditions [31]. scrum tactics: exploiting technical performances despite the emphasis on scrum force and body position in this review, in game settings scrum outcomes are also affected by tactics. during scrum contests, players may employ coached techniques that reduce their opponent’s ability to scrum effectively. ideally, front row players should contest directly against their opposite number, that is, the loose-head prop should push against the opposing tight-head prop. however, players frequently change height and angles at which they push to unsettle their opponent. as an example, loose-head props may attempt to “get underneath” their opposing tighthead prop with the aim to push them up and in towards their hooker rather than directly backwards. while illegal, these subtle variations in scrummaging technique are notoriously difficult on which to make a formal judgement.[7] other tactics employed include the deliberate wheeling of the scrum[14], facilitated by teams deliberately changing their foot position.[32] defending teams have also been known to wait for the attacking team to hook the ball (necessitating one player taking a foot off the ground), to produce a coordinated shove thereby taking advantage of this moment of instability. while it is likely that the scrum with the greater force production capacity will still dominate these contests, the skill required for players to maintain force production dynamically adjusting to this highly variable system should not be underestimated. conclusion the scrum contest is one of the quintessential parts of a rugby game. success here depends on the optimisation of joint angles and force production at the individual level, and coordination of effort at a team level. analysis presented here demonstrates that producing large scrum-specific forces and achieving the optimal ‘body shape’ are essential for scrum performance. clear relationships 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[http://dx.doi.org/10.1016/j.jsams.2009.04.004] [pmid: 19560972] https://doi.org/10.1016/j.jsams.2017.09.323 https://doi.org/10.1080/14763141.2018.1452972 https://doi.org/10.1519/jsc.0b013e318241382a https://doi.org/10.2165/00007256-200333130-00003 https://doi.org/10.1152/jappl.1991.71.2.644 https://doi.org/10.1016/j.jsams.2009.04.004 original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license comparing critical speed modelling approaches and exploring relationships with match-play variables in elite male youth soccer players kc liu,1 bsc; j sheard,1 bsc; t frixou,1 bsc; p milton,1 bsc; e prato luna,1 bsc; e piatrikova,1 phd; s williams,1 phd; j parr,2 phd; g roe,3 phd; m kramer,4 phd 1 department of health, university of bath, bath, uk 2 manchester united football club, manchester, uk 3 bath rugby, bath, uk 4 physical activity, sport, and recreation (phasrec) unit, north-west university, potchefstroom, south africa corresponding author: kc liu (kachun.liu@gmail.com) first interpreted by hill in 1925, the concept of critical power (cp) is mathematically described as the hyperbolic relationship between an individual’s sustainable power output during exercise and time to exhaustion.[1] cp is defined as the horizontal asymptote of power output on a power-time curve, below which exercise can be sustained for an extended (theoretically unlimited; in practice 20-60 mins) period of time.[2] exercise at or above cp; however, draws upon the individual’s additionally available work capacity represented by w′ (expressed in kj), the magnitude of which is finite and its depletion predictable.[2] in sports, such as cycling and rowing, three-point models from fixed-distance time trials are traditionally used to map an athlete’s power-time relationship.[3] however, conducting multiple tests is timeconsuming, labour-intensive, and aversive for the participants. this has been addressed through the development of a three minute all-out test (3mt) that provides valid and reliable estimates of cp and w′ as a single maximal test for both power and speed-based sports.[2,4] the average power output in the last 30 seconds of the 3mt was shown to decline to a relatively steady level that was almost identical to cp.[5] based on the linearisations of the power-time relationship,[6] the derived equation is expressed as: 𝑊′ = 150𝑠(p150s − cp) where p150s is the average power output across the first 150 seconds. this relationship also exists in running, where the terms critical speed (cs) and d-prime (d′) are used instead.[2] research on collegiate female distance runners has also shown that the 3mt is equally effective for measurements of cs and d′,[5] but there was a lack of interchangeability of results from a linear 3mt to an intermittent repeated-sprint based scenario. although the average running speed for repeated sprints is lower, there is a higher energy cost of accelerations from intermittent running,[7] where oxygen consumption (v ̇o2) requirements increase in proportion to speed and turn frequency.[8] nevertheless, recent evidence has shown that the 3mt can be modified to a shuttle run protocol that is equally valid to continuous running models. a length of 30 m allowed enough time to build up to near-maximal speeds, but was short enough to allow for a considerable number of turns.[9] in a recent study on team sport athletes, a novel biexponential model has emerged as another method of quantifying elements of the running 3mt, showing very strong and fit aspects to the data (r = 0.91-0.97) and high levels of agreement for estimates of cs and d′ against a graded exercise test.[10] for the shuttle-run 3mt, there are two methods of biexponential modelling that can be used to estimate the measures: an average speed method (bi-expaverage) that calculates cs using average speed per shuttle; and a maximum speed method (bi-expmax-speed) that uses peak shuttle speeds only. the bi-exponential model also reported additional physiological parameters of interest that can be obtained from the data (fig. 1), including smax (maximum speed of the trial), tmax (time to smax), τd (time constant reflecting rate of speed decline towards cs), and ad (amplitude of decline from smax to background: a novel bi-exponential method has emerged to estimate critical speed (cs) and d-prime (d′) from a 3-min allout test (3mt). objectives: to compare cs analysis methods to determine whether parameter estimations were interchangeable. reference values and relationships with key soccer matchplay variables were explored. methods: thirteen elite male youth (14-15 years old) players completed a 30 m shuttle run 3mt to estimate cs, d′, rate of speed decline time constant, maximal speed (smax), time to smax (tmax), and fatigue index (fi), using the traditional method and bi-exponential model on average (bi-expaverage) and max speed settings (bi-expmax-speed). high-speed running (hsr) and sprinting distances and counts, and the number of accelerations were collected from two matches. magnitudebased inferences (p < 0.05) with smallest worthwhile change of 0.2 effect sizes were used to analyse differences. pearson’s and spearman’s correlation coefficients were used to measure associations between cs model variables and match-play parameters. results: there were significant differences between the traditional method and both bi-exponential models for cs and d′, as well as between the bi-exponential models for all variables except tmax. using the bi-expaverage model, strong correlations (r = 0.70-0.73; p < 0.05) were observed for d′ and fi with the number of standardised and individualised hsrs, respectively. with the bi-expmax-speed model, there were strong correlations (r/ρ = 0.64-0.68; p < 0.05) between d′ and the number of standardised hsrs and sprints, and the number of individualised sprints. conclusion: there is a lack of interchangeability between analysis methods. it appears that d′ and fi from the biexponential models could be associated with high-intensity actions in soccer match-play. keywords: bi-exponential, critical power, reference, performance s afr j sports med 2021;33:1-6. doi: 10.17159/2078-516x/2021/v33i1a9738 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9738 https://orcid.org/0000-0002-2535-6498 https://orcid.org/0000-0002-1539-5610 https://orcid.org/0000-0003-2237-7549 https://orcid.org/0000-0003-3251-8990 https://orcid.org/0000-0001-7735-2977 https://orcid.org/0000-0003-1428-9282 https://orcid.org/0000-0003-1460-0085 original research sajsm vol. 33 no. 1 2021 2 cs). since ad effectively describes a reserve for speeds above cs, it was used to derive a fatigue index (fi), defined as the speed reserve as a percentage of smax.[10] it was suggested that smaller fi values represented lower levels of fatigability, thus a disposition to endurance exercise.[10] due to the novelty of the bi-exponential model, comparisons with existing shuttle running evidence have not yet been established, and so the interchangeability of results between methods is currently unclear. although research on cs has mainly been applied to soccer[6,11] and rugby,[4,8] to date only one study has explored the use of the cs concept to the classification of match running performance.[12] to our knowledge, there are currently no studies that have examined the relationship between cs parameters (as derived from the 3mt) and key match-play physical performance variables in team sports. therefore, the three-fold objective of this study was to provide specific insights based on a soccer population. the first objective was to compare cs parameters obtained using different models from the shuttle running 3mt, when compared between the traditional, bi-expaverage, and biexpmax-speed analysis methods. the second objective was to establish reference values from all three analysis methods. the final objective was exploratory, namely to provide novel insight into possible relationships between cs parameters and key match-play variables. methods participants thirteen competitive, elite youth male soccer players (age 15.2±0.2 years, height 171.3±7.0 cm, weight 59.0±7.8 kg) from an english premier league academy were recruited. pacing was detected in the 3mt time trial from one player and so his data were excluded, resulting in a total of twelve players. testing occurred around the middle of the season, and all participants were engaged in training, as well as strength and conditioning programmes, at the time. as all athletes were under the age of 16 years old, written informed consent was given by their parents or guardians along with written informed assent from the athletes, and approved by the university of bath research ethics approval committee for health in accordance with the declaration of helsinki. protocol the current study is of a cross-sectional observational nature. the participants underwent two shuttle-run 3mt trials in the evening under dry weather conditions on a grass surface. the trials were separated by 72 hours to allow for sufficient recovery, and the participants did not take part in any matches for at least 48 hours prior to each trial. the first trial was used as a familiarisation part of the trial, with the second acting as the main trial for data collection. the protocols consisted of continuous maximal effort, namely, 30 m shuttle sprints for a duration of 185 seconds, without any indication of time remaining throughout to prevent pacing. the trials were conducted at the beginning of training after a regular warm-up to prevent fatigue from influencing the results. an extra five seconds were added to ensure that the three minutes of data were available for all participants. participants also completed two 80-minute matches with a 15-minute break between halves, 48-60 hours prior to each trial. data from the trials and matches were collected using an 18 hz global positioning system’s (gps) units (apex pro series, statsports, county down, northern ireland), positioned between the participants’ scapulae in a tight-fitted vest. the accompanying software was used for data extraction. for the 3mts, instantaneous speed (m·s-1) was obtained for every time point. the data were processed using the traditional method and the bi-exponential models in an excel spreadsheet[10] to calculate cs, d′, smax, tmax, τd, and ad, based on methods presented in other published literature.[5,10] match-play variables were obtained for the final 15 minutes of each half only, as the disparity between physical capabilities is more likely to be differentiated when fatigue starts to influence output.[13] the metrics obtained were high-speed running (hsr; ≥5.5 m·s-1) and sprinting (≥7.0 m·s-1) distances, and number of accelerations (≥2.0 m·s-2). a python script (connor, 2020) was also employed to obtain the number of hsr and sprinting counts based on the standardised thresholds, as well as hsr and sprinting distances and counts based on individualised thresholds. each player’s cs and smax were used as their individualised hsr and sprinting thresholds respectively, which were repeated for all three analysis methods. dwell time was set at 0.5 seconds for an action count to register. each half of the matches was treated separately, and only data from players who started the half were included to ensure playing time leading up to the last 15 minutes was equal. data from five players who participated in both match fixtures fig. 1. example of a speed-time graph of a running 3-minute all-out test analysed using the bi-exponential model. the highlighted shuttle demonstrates the difference between max and average (avg) speeds used for modelling. cs, critical speed; d’, d-prime original research 3 sajsm vol. 33 no. 1 2021 were averaged prior to inclusion in the final analysis. statistical analysis normality of all data were assessed with the shapiro-wilk test. to answer the first objective, we utilised magnitudebased inferences (mbi) with a 95% confidence level, alphalevel of p = 0.05, and smallest worthwhile change of 0.2 for cohen’s d effect sizes (es) to evaluate the differences between variables estimated from the traditional and bi-exponential methods. es values were interpreted using the following scale: d < 0.2, trivial; < 0.6, small; < 1.2, moderate; < 2.0, large; < 4.0, very large; and ≥ 4.0, extremely large.[14] for the second objective, reference values were calculated using averages (i.e. mean ± standard deviation) for all three methods. finally, in alignment with the third objective, we used pearson’s or spearman’s correlation coefficients to explore relationships between physiological variables from the 3mt shuttle-run test and match-play metrics. the correlation test was chosen based on the normality of each dataset. specifically, cs was analysed against distance measures, d′ against action counts, and fi against all metrics. correlation values were interpreted using the following scale: r/ρ < 0.2, very weak; < 0.4, weak; < 0.6, moderate; < 0.8, strong, and ≥ 0.8, very strong. results comparison between methods of analysis the differences in chosen cs variables between methods of analysis are reported with cohen’s d and derived mbis in tables 1, 2, and 3, along with raw values and es interpretations. table 1. comparisons of variables between traditional method and bi-expaverage model variable meandiff p-value cohen’s d 95% ci effect size interpretation mbi cs (m·s-1) -0.07 0.02 -0.42 -0.76, -0.08 small likely negative d’ (m) 67.84 < 0.01 4.16 3.41, 4.91 almost certain most likely positive bi-expaverage, average speed bi-exponential; meandiff, mean of bi-expaverage model – mean of traditional method; cs, critical speed; d’, d-prime; ci, confidence intervals; mbi, magnitude-based inferences. negative mbi denotes a larger value in the traditional method. table 2. comparisons of variables between traditional method and bi-expmax-speed model variable meandiff p-value cohen’s d 95% ci effect size interpretation mbi cs (m·s-1) 0.71 < 0.01 3.85 3.46, 4.25 very large most likely positive d’ (m) -13.58 0.03 -0.86 -1.61, -0.11 moderate very likely negative bi-expmax-speed, max speed bi-exponential; meandiff , mean of bi-expmax-speed model – mean of traditional method.; cs, critical speed; d’, d-prime; ci, confidence intervals; mbi, magnitude-based inferences. negative mbi denotes a larger value in the traditional method. table 3. comparisons of variables between bi-expaverage and bi-expmax-speed models variable meandiff p-value cohen’s d 95% ci effect size interpretation mbi cs (m·s-1) 0.78 < 0.01 4.41 4.10 to 4.71 extremely large most likely positive d’ (m) -81.41 < 0.01 -7.06 -7.41 to -6.71 extremely large most likely negative τd (s) -3.88 0.09 -0.39 -0.86 to 0.07 small likely negative tmax (s) -0.24 0.42 -0.12 -0.45 to 0.20 trivial possibly trivial smax (m·s-1) 1.74 < 0.01 6.87 6.20 to 7.55 extremely large most likely positive fi (%) 6.8 < 0.01 1.41 1.09 to 1.74 large most likely positive bi-expaverage, average speed bi-exponential; bi-expmax-speed, max speed bi-exponential; meandiff, mean of bi-expmax-speed – bi-expaverage model.; cs, critical speed; d’, d-prime; τd, time constant reflecting rate of speed decline towards cs; tmax, time to smax; smax, maximum speed; fi, fatigue index; ci, confidence intervals; mbi, magnitude-based inferences. negative mbi denotes a larger value in the traditional method. table 4. reference values of traditional method, bi-expaverage, and bi-expmax-speed models variable traditional method bi-expaverage model bi-expmax-speed model mean sd 95% ci mean sd 95% ci mean sd 95% ci cs (m·s-1) 3.42 0.17 3.31 to 3.51 3.35 0.15 3.27 to 3.44 4.13 0.20 4.01 to 4.24 d’ (m) 58.82 19.52 47.77 to 69.86 126.65 12.29 119.70 to 133.61 45.24 10.71 39.18 to 51.30 τd (s) 37.99 9.97 32.35 to 43.63 34.11 9.69 28.63 to 39.59 tmax (s) 4.70 2.00 3.57 to 5.83 4.46 1.86 3.41 to 5.51 smax (m·s-1) 5.00 0.11 4.94 to 5.06 6.74 0.34 6.54 to 6.93 fi (%) 39.0 5.1 36.1 to 41.9 45.8 4.6 43.2 to 48.4 bi-expaverage, average speed bi-exponential; bi-expmax-speed, max speed bi-exponential; cs, critical speed; d’, d-prime; τd, time constant reflecting rate of speed decline towards cs; tmax, time to smax; smax, maximum speed; fi, fatigue index; ci, confidence intervals; mbi, magnitude-based inferences. negative mbi denotes a larger value in the traditional method. original research sajsm vol. 33 no. 1 2021 4 there were statistically significant differences in all variables between the traditional method and both bi-exponential models. comparisons between the two bi-exponential models also found statistically significant differences in all variables except for tmax. reference values reference values are represented by squad averages in table 4, along with standard deviations and 95% confidence intervals. results from all three methods of calculations are shown separately. relationships between key variables exploratory correlations between cs, d′, fi, and key matchplay variables from the last 15-minute periods of each half are shown in tables 5, 6, and 7. no statistically significant correlations were found between cs and distances covered above high-intensity running-speed thresholds. d′ derived from both bi-exponential models showed strong correlations to the number of standardised hsr efforts. similarly, strong relationships were found between d′ from the bi-expmax-speed model and both the number of standardised and individualised sprinting efforts. finally, fi from the biexpaverage model also exhibited a strong correlation to the number of individualised hsr actions. discussion the key results of this study are threefold. firstly, comparisons between the three calculation methods show that there are small to extremely large differences in all values, with the exception of tmax being possibly trivial. next, reference values were presented for all variables for a male elite youth soccer population. finally, strong correlations were found between bi-exponential d′, fi, and certain measures of hsr efforts. the differences in cs values between the bi-exponential and traditional methods can be attributed to the fact that the biexponential models detect when shuttle speeds level off, instead of calculating from a standardised final 30 seconds. indeed, the 0.71 m·s-1 larger cs from the bi-expmax-speed model versus the traditional method can be explained by the model’s use of only shuttle peak speeds, thus excluding the periods of lower velocity during accelerations and decelerations. for d′ from the bi-expaverage and bi-expmax-speed models, the 67.84 m larger and 13.58 m smaller mean, respectively, can be explained by the bi-exponential models calculating the area under the curve rather than averaging the speed from the initial 150 seconds. due to the larger cs from the bi-expmax-speed model, the lower d′ values are in line with the well-established inverse relationship between the two parameters.[2,3] as cs is higher for the same individual maximal oxygen uptake (v̇o2max), the range of available work capacity above the threshold is accordingly reduced. the larger smax and fi averages from the bi-expmax-speed compared with the bi-expaverage model were also to be expected, due to the nature of the speed values and the calculation formulas used. this is supported by a study that found larger speed decrements when max speed is higher[15] suggesting a lower level of endurance that can be represented by the larger fi values seen. although parameter differences between models may appear to be purely semantic, it is important to remember that cs and d’ have been successfully used in individualised training prescription.[5] therefore, the magnitude of cs and d’ derived table 5. correlation coefficients between critical speed and match-play distance measures method std. hsr ind. hsr std. sprint ind. sprint traditional 0.37 0.04 0.05 bi-expaverage 0.25 0.11 0.04 0.17 bi-expmax-speed 0.32 -0.19 0.10 0.15 bi-expaverage, average speed bi-exponential; bi-expmax-speed, max speed bi-exponential; ind, individualised; std. hsr, standardised high-speed running (≥ 5.5 m·s-1); std. sprint, standardised sprint (≥ 7.0 m·s-1); *p < 0.05. table 6. correlation coefficients between d’ and match-play action count measures method no. of std. hsr no. of ind. hsr no. of std. sprint no. of ind. sprint traditional -0.19 0.14 0.14 bi-expaverage 0.73* 0.52 0.36 -0.33 bi-expmax-speed 0.68* 0.34 0.64* 0.64* bi-expaverage, average speed bi-exponential; bi-expmax-speed, max speed bi-exponential; ind, individualised; std. hsr, standardised high-speed running (≥ 5.5 m·s-1); std. sprint, standardised sprint (≥ 7.0 m·s-1); *p < 0.05. table 7. correlation coefficients between fatigue index (fi) and match-play key variables of interest method std. hsr ind. hsr std. sprint ind. sprint no. of std. hsr no. of ind. hsr no. of std. sprint no. of ind. sprint no. of accelerations bi-expaverage 0.12 0.02 0.28 0.06 0.56 0.70* 0.50 -0.24 < 0.01 bi-expmax-speed 0.29 0.11 0.52 -0.11 0.52 0.59 0.57 0.57 -0.09 bi-expaverage, average speed bi-exponential; bi-expmax-speed, max speed bi-exponential; ind, individualised; std. hsr, standardised high-speed running (≥ 5.5 m·s-1); std. sprint, standardised sprint (≥ 7.0 m·s-1); *p < 0.05. original research 5 sajsm vol. 33 no. 1 2021 from a model can have significant influences in time-toexhaustion efforts, as well as performance and training success at the individual level. the present study therefore highlights the meaningful differences in parameter estimates, and future research should therefore investigate which model provides more useful shuttle-based cs and d’ parameters for training prescription. together, the present data implies that results obtained from different calculation methods cannot be interpreted interchangeably, especially for measures of cs, d′, smax, and fi. sports science practitioners and researchers should only make comparisons for data derived from the same calculation method, otherwise conclusions will be erroneous and inaccurately reflect the nature of any physiological differences within individuals and between groups. based on the importance of accelerations and decelerations to physical performance in soccer[16], the use of the traditional method or bi-expaverage model may be more appropriate for training prescriptions to be able to mimic match-play demands. on the other hand, the bi-expmax-speed model could serve better for longitudinal monitoring purposes, as its focus on shuttle peaks may allow for the capture of loads above speed thresholds with larger physiological impacts. as it had been shown that shuttle-run 3mts of varying distances produces differences in measures,[8,11] future research should investigate comparisons using different shuttle lengths that are more suitable to other team sports to determine whether similar discrepancies between the analysis methods exist. reference data were presented in this study for an elite male u16 soccer population. aside from the well-established cs and d′ metrics, additional physiological parameters introduced by the bi-exponential models were also reported. as τd is the time constant reflecting the rate of speed decline, higher values can possibly represent a better speed endurance ability in maintaining speeds above cs. lower values of tmax can suggest a greater accelerating capability to reach top speed within 30 m, represented by a higher smax. finally, fi can be used as a measure of fatigability, with a lower value suggesting a propensity for higher endurance capacity.[10] these qualities are critical to performance in not only soccer, but also across a variety of intermittent sports. a recent quasi meta-analysis on field sports athletes based on the traditional method found a mean cs of around 3.5 m·s1 and d′ of around 225 m.[17] although cs is comparable to the mean of 3.42 m·s-1 in this study, d′ was much larger than the 58.82 m from our population. however, a key point to consider is that the average participant age from the four studies included ranged from 19-24 years. the difference in maturation status in comparison to u16 players might explain at least some of the discrepancies. three of the studies used varying shuttle distances ranging from 20-50 m, and one in fact conducted a linear 3mt instead, whilst two included female participants. as a result, comparisons drawn between studies cannot be conclusive, as research has shown that measure outcomes are specific to 3mt protocols,[8] and gender differences were not addressed. lastly, the exploratory correlations examined provide an insight into possible relationships between measures of the cs concept and key match-play variables. several statistically significant associations, which could be considered strong based on the correlation coefficients, were found between biexponential d′, fi, and measures of hsr and sprint counts. since d′ and fi represent work capacity and fatigability respectively, positive associations with high-intensity actions in latter stages of each half can be deemed reasonable. these ideas are in line with research that found negative effects of fatigue on high-intensity activity in the latter stages of halves,[13] which can in turn suggest that larger physiological capacities allow for more pronounced physical performance capabilities. no significant relationships were found with the other variables explored. neither bi-exponential models seemed to show stronger links than the other. the small number of effects observed can be attributed to several limitations within this study, mainly the limited sample size of participants. there was also a lack of consideration for match status during the 15minute periods, as being in a winning, drawing, or losing position can affect motivation to engage in high-intensity activity.[18] the team’s tactical approaches and prior success,[19] quality of opposition, as well as each individual’s status (e.g. recovery and wellness) may also affect physical output. it is hoped that the results of the present study may provide impetus for future research pertaining to the relationship between parameters derived from the 3mt and actual matchplay as such information is currently lacking. conclusion in conclusion, the analysis of shuttle-run 3mts using the traditional method and bi-exponential models produced significantly different values for all but one metric calculated. therefore, results are not interchangeable and researchers must interpret data from existing literature with some caution. the male youth soccer reference values provided may guide practitioners in fitness diagnostics, performance evaluation, and training prescriptions. exploratory correlations found between key variables suggest possible relationships exist between bi-exponential d′, fi, and high-intensity running actions in match-play. this proposes applicability to the appraisal of a player’s ability to perform actions that can affect match outcomes. finally, results and ideas presented in this study warrant more extensive research, and scope for future investigations have been discussed. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors would like to thank mark connor for his assistance with data processing for this study. author contributions: all authors were involved in the study design, data acquisition and analysis, drafting and reviewing process, and the final publication approval. references 1. hill dw. the critical power concept a review. sports med 1993; 16(4): 237-254. [doi: 10.2165/00007256-19931604000003][pmid: 8248682] original research sajsm vol. 33 no. 1 2021 6 2. jones am, vanhatalo a. the 'critical power' concept: applications to sports performance with a focus on intermittent high-intensity exercise. sports med 2017; 47(suppl 1): 65-78. [doi: 10.1007/s40279-017-0688-0][pmid: 28332113] 3. vanhatalo a, jones am, burnley m. application of critical power in sport. int j sports physiol perform 2011; 6(1): 128136. [doi: 10.1123/ijspp.6.1.128][pmid: 21487156] 4. kramer m, clark ie, jamnick n, et al. normative data for critical speed and d′ for high-level male rugby players. j strength cond res 2018; 32(3): 783-789. [doi: 10.1519/jsc.0000000000001880][pmid: 28542091] 5. pettitt rw, jamnick n, clark ie. 3-min all-out exercise test for running. int j sports med 2012; 33(6): 426-431. [doi: 10.1055/s0031-1299749][pmid: 22422309] 6. clark ie, west bm, reynolds sk, et al. applying the critical velocity model for an off-season interval training program. j strength cond res 2013; 27(12): 3335-3341. [doi: 10.1519/jsc.0b013e31828f9d87][pmid: 23478481] 7. polglaze t, hogan c, dawson b, et al. classification of intensity in team sport activity. med sci sports exerc 2018; 50(7): 1487-1494. [doi: 10.1249/mss.0000000000001575] [pmid: 29432324] 8. kramer m, watson m, du randt r, et al. critical speed as a measure of aerobic fitness for male rugby union players. int j sports physiol perform 2019; 14(4): 518-524. [doi: 10.1123/ijspp.2018-0411][pmid: 30300035] 9. saari a, dicks nd, hartman me, et al. validation of the 3minute all-out exercise test for shuttle running prescription. j strength cond res 2019; 33(6): 1678-1684. [doi: 10.1519/jsc.0000000000002120][pmid: 28723814] 10. kramer m, du randt r, watson m, et al. bi-exponential modeling derives novel parameters for the critical speed concept. physiol rep 2019; 7(4): e13993. [doi: 10.14814/phy2.13993][pmid: 30784213] 11. kramer m, du randt r, watson m, et al. oxygen uptake kinetics and speed-time correlates of modified 3-minute all-out shuttle running in soccer players. plos one 2018; 13(8): e0201389. [doi: 10.1371/journal.pone.0201389][pmid: 30130362] 12. lord c, blazevich a, abbiss cr, et al. comparing maximal mean and critical speed and metabolic powers in elite and subelite soccer. int j sports med 2020; 41(4): 219-226. [doi: 10.1055/a-1065-2100][pmid: 31968382] 13. mohr m, krustrup p, bangsbo j. fatigue in soccer: a brief review. j sports sci 2005; 23(6): 593-599. [doi: 10.1080/02640410400021286][pmid: 16195008] 14. hopkins wg, marshall sw, batterham am, et al. progressive statistics for studies in sports medicine and exercise science. med sci sports exerc 2009; 41(1): 3-13. [doi: 10.1249/mss.0b013e31818cb278][pmid: 19092709] 15. buchheit m, bishop d, haydar b, et al. physiological responses to shuttle repeated-sprint running. int j sports med 2020; 31(6): 402-409. [doi: 10.1055/s-0030-1249620][pmid: 20422503] 16. akenhead r, hayes pr, thompson kg, et al. diminutions of acceleration and deceleration output during professional football match play. j sci med sport 2013; 16(6): 556-561. [doi: 10.1016/j.jsams.2012.12.005][pmid: 23333009] 17. kramer m, thomas ej, pettitt rw. critical speed and finite distance capacity: norms for athletic and non-athletic groups. eur j appl physiol 2020; 120(4): 861-872. [doi: 10.1007/s00421020-04325-5][pmid: 32086601] 18. redwood-brown a, o'donoghue pg, robinson g, et al. the effect of score-line on work-rate in english fa premier league soccer. int j perform anal sport 2012; 12(2): 258-271. [doi: 10.1080/24748668.2016.11868938] 19. di salvo v, gregson w, atkinson g, et al. analysis of high intensity activity in premier league soccer. int j sports med 2009; 30(3): 205-212. [doi: 10.1055/s-0028-1105950][pmid: 19214939] editorial the 1970’s were a pivotal time for sports medicine. for reasons that are still unclear, long distance, especially marathon running suddenly developed as a popular recreational activity for many thirtysome thing’s who had not previously considered themselves to be particularly athletic. the result was that the numbers o f entrants in road races such as the new york and london marathons and our own comrades marathon, suddenly jumped from a few hundred to tens o f thousands. whilst this passion for marathon running has dissipated somewhat in the last 5 years, its influence is still felt with the growth in participation in diverse recreational activities including aerobics and other gymnasium activities, cycling, walking and hiking, and water sports. but perhaps the greater contribution ol the 1970’s to sports medicine was the acceptance o f podiatry as a crucial component in injury treatment and prevention especially in mechanically repetitive sports like running. prior to the 1970’s, the management o f these injuries followed a traditional approach that focused exclusively on the site o f injury. no attention was given to an understanding o f why the injury hap­ pened in the first place. as a result, the majority o f injured runners in those years soon became ex­ runners. fortunately the skills o f an evolving profession in north america soon began to seek answers in an unusual direction. these podiatrists spearheaded by d r richard schuster in new york and drs john pagliano and steve subotnick in california, inspired a revolution in our understanding o f how these injuries occurred. their genius was to suggest that identifiable and correctable abnormalities in the lower limb could explain why these injuries were resistant to our conventional treatments which failed to acknowledge their importance. in this edition o f the journal, guest editor dennis rehbock and his colleagues address these issues in the first edition o f our journal ever to be dedicated exclusively to podiatry. we are also privileged to include a paper from one o f these inspirational podiatrists d r john pagliano who describes his with management o f the iliotibial band friction syndrome, perhaps one o f the running injuries that is most resistant to therapy. his ideas will be o f value to all who struggle with this injury. recently a local cape newspaper carried the interesting opinion o f a leading politician who was dissatisfied with what he saw as the fragmentation o f medical services. his specific complaint was that prior to and following major hip surgery, he had not been referred for a programme o f exercise rehabilitation. yet when, on his own initiative, he had availed himself o f this treatment, he had experienced substantial benefit. whv, he wanted to know, was such referral not routine? sports medicine is leading the way in showing that sportsmen and women, regardless o f their ability, benefit most from a multi disciplinary approach, involving experts from a wide range o f fields. it is a pleasure for this multidisciplinary journal, to provide our podiatric colleagues with the appropriate forum to display their expertise. professor tim noakes editor sports medicine june 1997 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) guest editorial dennis rehbock guest editor t h is issue o f the jo u rn a l is d evoted to podiatrie s p o ils m edicine. it gives me g reat pleasure to be the guest editor o f th is issue o f the sou th african jo iu n a l o f s p o rts m edicine. in so u th a frica we are a very sm all group o f p o d iatrists w ith an interest in sports m edicine and podiatrie sports m edicine. cxufield o f interest h as developed over many years, based 011 a m erican podiatrie sports m edicine and our own experiences. throu gh personal contacts, increasing involvement in treating sports injuries, and more recently the presentation o f podiatrie p ap ers at so u th african s p o rts m edicine association ( s a s m a ) c o n gresses, we arc being recognised for oiurole in the m anagem ent o f injured sportsm en and women. with the m odern m u lti-d isciplinary approach to the managem ent o f sportsm en and women, the importance o f biom echanical an alysis and treatm ent o f the feet and lower limb becom es vital for im proved perform ance and injury prevention and treatm ent. mr b ernhard zip fcl d escrib e s how forefoot varus, a common foot type, can influence su b talar joint pronation. t h is foot type c a u se s com pensatory ovcrpronation in the foot and may need b io m cchanical correction. b ernhard z ip fcl is program m e le a d e r o f the podiatry departm en t o f the t cch n ikon w itw atcrsran d and a p ractisin g p odiatrist in the west rand. mimike e ls p ro vid es us with a review o f sc sa m o id itis o f the first m etatarsal. a11 increase in the w eight b earing b allistic types o f sport h as resulted in this injury becom ing more common. mike e ls is a lecturer at the p o d iatry d ep artm en t o f the t cchnikon w itw atcrsran d and a practisin g p o d iatrist in albcrton. ah’ darryl coh en d e sc rib e s the effect o f excessive pronation o f the foot 011 patcllofcm oral pain syndrom e. t h is h ig h ligh ts the role o f the podiatrist in the treatm ent o f patcllofcm oral pain syndrom e bv m eans o f biom cch anical an alysis and the prescription o fo rth o tic therapy. darryl cohen is a practisin g p o diatrist in jo h a n n e sb in g . in this jo u rn a l i have included som e work by dr jo h n pagliano. d r pagliano is a very old friend and colleague from long b each california in the united s ta te s o f am erica. h e is a practisin g podiatrist in a m e rica with a great interest in podiatrie s p o ils m edicine. dr pagliano p resented a paper and a clinical workshop at the 1995 s a s m a c on gress in d iubau. mr p h ilip c a rste n s looks at a podiatrie approach to sonic cycling injm ies. t h is is a sport that is not often associated with foot and lower limb injiuies. philip c arsten s is a p ractisin g p odiatrist in c ap e town. a s sp o rts p o d ia trists we are being called upon to take otu place in the field o f sp orts m edicine. oiu recognition by the sports m edicine fraternity and the south african s p o rts m edicine a ssociation will urge 11s to new h eig h ts o f excellence in our field o f podiatrie sports m edicine. q reoprilvgel on-the spot-pain relief 2 sports medicine june 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the s o i’tii african jol'ryye of sports medicine vo l i tver 4 number 2 jihve 1997 editors i’rof td noakes contents j)r m p scliwellniis editorial 1 editorial board td noakes d r m e mnnlla d r p de jayer guest editorial 2 dr ,j skotvno d rehbock dr p schwartz p ro f k stretch d r ( ' de iiidder pro/ 1 > ( ' andrews forefoot varus and it’s influence on 4 subtalar joint pronation dr e it derman b zipfel mr r i i farman a review of sesamoiditis of the firsti)r r ii mars 6 dr ( ' a noble metatarsal m els international advisory board l ijle ,! micheli associate clinical professor o f orthopacd ic sn rgc ry excessive pronation as an etiology in patellofemoral pain syndrome 7 boston, usa d cohen chester r kyle research director, sports equipment research associates iliotibial band svndrome (itbs) in 9 california, usa * lon£ distance runners pro/’i k ' wildor hollmann prasident dcs deutschcn j w pagliano sportarztcbundcs kohl, west germany a podiatric approach to common lower 12 howard j green professor, department o f extremity injuries in cycling kinesiology ontario, canada pa carstens george /i brooks professor, department o f physical education california, usa neil f gordon director, exercise physiology texas, usa edmund k burke associate professor, biology department, university of colorado colorado, usa graham x smith physiologist glasgow, scotland t h e e d ito r t h e so u th african jo u rn a l o f s p o rts m edicine p o b o x 115. new latuls 7725 production andrew thomas pu b lish in g g len barr publishers cc private bug x14 parkliinds 21ik) tel: ( o i l ) 442-9759 fax: (0 1 1 ) 880-7898 ad vertising marika de waal/andivw thomas reproduction ( ) n ( i> n i r e ] i r o d i h ’ t i o n pr in tin g 1 iortors rep^rijcgel on-the-spot-paln relief the views expressed in individual articles arc the personal views of the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent of the publishers. sports medicine june 1997 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) forefoot varus and it’s influence on subtalar joint pronation bernhard zipfel nhd pod(sa), nhd ps ed(sa) introduction forefoot vams is a well recognised loot type and the measurement o f the forefoot angle eonipared lo tire rearfoot is commonly referred to in podiatrie literature. different disciplines appear to have differing opinions on the definition o f forefoot varus and its role in caus­ ing lower limb pathology which may lead to a lack o f understanding o f the etiology o f many lower limb injuries especially in long distance runners. forefoot varus was first defined by root et al.' as an inverted position o f the forefoot in relationship to the rearfoot. this is a frontal plane deformity and can be readily seen from the posterior view o f the foot by creating a line perpendicular to the bisection of the calcaneus which represents the transverse plane o f the rearfoot. this line is then compared to the plantar surface o f the metatarsals and any angulation between the two lines determines the degree o f forefoot varus present .this comparison is made with the subtalar joint in neutral and the forefoot (midtarsal joint) fully pronated. the etiology of forefoot varus is thought to be a delayed derotation o f the head and neck o f the talus and decreases from 5 degrees (below 5 years) to 2 degrees in the adult according to tax (1965).;u excessive angu­ lation o f the forefoot in relation to the rearfoot com­ monly results in compensatory subtalar joint overpro nation and may result in lower limb injuries especially in long distance runners.’ neutral position and the recognition o f forefoot varus during the stance phase o f the gait cycle, the subtalar joint moves through the motions o f pronation and supination in order that the foot may act as a mobile adapter (pronation) dining the contact and midstance phase and a rigid lever (supination) dining the propid sive phase. the primary reasons for these motions is to make the foot function more efficiently and thereby reduce the incidence o f injury’.*'’ the foot strikes the ground in a supinatcd position, moves into a pronated position in order lo absorb shock and resupinates in order to propel the body forward.' in order for the sub­ talar joint to move from a supinatcd position into a pronated position it must go through a neutral position in which the joint is neither pronated nor supinatcd. this occurs shortly after heel strike and just before heel lift. at the point before heel lift the foot is still flat on the groimd with the body weight peqiendicular to the foot. the groimd reaction forces load the lateral side o f the forefoot, dorsiflexing the fifth metatarsal head and fully pronating the midtarsal joint1'" into a position perpendicular with the posterior bisection of the calcaneus. this occurs because the natural noil weightbearing position o f the forefoot is slightly invert­ ed and the evcrsion range o f motion is usually available to a llo w th e fo refo o t lo a d ap t to th e w eiglil b ea rin g position . at th is c ritic a l point d u rin g the stance ph ase the su b talar joint, is n eutral and the m id ta rsa l jo in t fid lv p ron a ted so that the foot is n e ith e r p ron a ted nor su pin atcd. root ct al.' stated that the foot, at lliis p oin t in the g a it cy c le is in it ’s m ost functional p o sition and th at th e tim in g o f th is neutral p o sitio n is essen tia l in d e te rm in in g th e c o n e d am ount o f supination for e f f i ­ cien t prop u lsion and to e -o fl.’ ' w ern iek an d i.anger'* d e fin e d su b talar joint n eu tral as th e p alp ation of th e h e a d o f th e ta in s a tta in in g o s s e o u s co n g ru e n c y b e tw e e n th e h ead o f th e talus and th e n avicu lar bone. the la tera l s id e o f th e fo o t is lo a d ed to resista n ce so llial lhe m id ta rsa l jo in t is fully p ro n a te d .' by m an ip u ­ lating th e fo o t in to th is p o sition (figiue 1), th e critica l point just b e fo re h eel lift can be s im u la ted and any b io ­ m ech a n ica l a b n o rm a litie s seen. observations are best don e w ith lhe patient pron e (figiue 2). figure 1. neutral position. note position o f hands. figure 2. the classic position for observing forefoot varus. striclly speaking, forefoot varus is an osseous frontal plane deformity,'1 but an element o f soft tissue involve­ ment may be present,' especially in children’ "’ which 4 sports medicine june 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) is indicated by reduced niidtarsal joint range o f motion. this is difficult to determine, as niidtarsal joint range o f motion lias 110 fixed parameters. the soft tissue component o f forefoot invert us is referred to as forefoot supinatus. the use o f these terms is purely academic, as the resulting compensa­ tion is the same regardless o f the etiology causing the forefoot to be inverted. the compensatory mechanisms o f forefoot varus forefoot varus compensates by subtalar joint prona­ t i o n . j o n e s and todd'slated that a greater than 4 degree forefoot varus will cause niaximiun evcrsion o f the calcaneus provided that the evcrsion range o f motion is available at the subtalar joint (figiue 3). the residting compensatory pronation has been recognised in the beginning walker4" and subotnicks identified that forefoot compensatory pronation results in many problems o f the medial aspect o f the foot, ankle and leg and may result in lumbar lordoses caus­ ing back pain. i11 short, compensatory ovcrpronation may be responsible for almost any common running injiu v o f the lower extremity. figure 3. forefoot varus in neutral non-weightbearing position and compensated weightbearing position. should t he evcrsion range o f motion not be avai lable in the subtalar joint, the joint will maximally evert and this is known as part ial compensation.” an example of this could be that there is a forefoot varus o f 10 degrees, but the eversion range o f motion at the subta­ lar joint is only 5 degrees and the joint can thus only compensate 5 degrees for the 10 degree forefoot varus. in the rare event o f there being no evcrsion range o f motion available in the subtalar joint, then the forefoot varus wotdd remain lmconipensatcd and the foot would function in a snpinated position. when full compensa­ tion takes place and the foot remains pronated before and after heel lift, the foot does not adequately resupinate for propulsion and toe off. this residts in instability o f the foot and that is transferred into the leg with the potential for causing a number o f foot and lower limb injuries. should partial or no compensation take place, then the subtalar joint will attempt to evert at the calcaneus, and unable to do so adequately, result in unnatural stresses being applied to the joint and surrounding tissue. the measurement o f forefoot varus philips'1' put emphasis on the measurement o f forefoot varus in orthotie manufacture. yale” referred to the forefoot measuring device. spencer'’ and seibcf described the use o f both the forefoot measuring device and the tractograph in measuring forefoot varus. these measurements are difficult and poor residts are obtained."’ c)mjcjn 1 ic 11 (199o)" suggested that there is poor inter-examiner reliability using the forefoot measuring device and it can be presumed that similar devices currently in use do not consistently pro­ duce the same results as they work 011 the same prin­ ciple. much has been said about the degree o f forefoot varus producing compensatory pronation41' " and sur­ gical evaluation was described by mcglamry et al" but there has been a failiue to determine the repeatability' and reproducibility o f forefoot varus measurements. the classical instruments used for the measure­ ment o f forefoot varus are the forefoot measuring device, which is difficult to use and gives poor mea siuenicnt"’ and the tractograph or goniometer which is easier to use than the forefoot measuring device.1 both methods require the forefoot to be compared to the posterior calcaneal bisection, which is technically to achieve consistently.17 literature quantifies forefool varus in terms o f degrees, but fails to explain exactly how these measurements were taken nor does it con­ sider the accuracy o f standard methods o f measure­ ment. conclusion forefoot varus is an extremely common foot-type and is responsible for compensatory overpronation in a large percentage o f distance nmncrs resulting in many o f the common running injuries. by understanding the bio mechanics o f forefoot van is, the etiology o f pronation and subsequently the resulting injury can be diagnosed and treated. although this foot type is difficult, if not impossible to measure, the most common method of ‘measurement’ is to subjectively estimate the degree of deformity, which appears to be adequate in the author’s opinion for clinical purposes. the harmful effects o f subtalar compensation can be reduced by modifying the socldiner innersole o f the running shoe with a forefoot medial wedge made o f eva or similar material. in some cases it may be necessary' to make a neutral orthosis with forefoot medial postmg depend­ ing 011 the amount o f control required. in both cases the ground is in effect brought up to the forefoot, instead o f the forefoot rolling down onto the ground forcing the subtalar joint to compensate by pronating. many common running injuries can be adequately man­ aged by limiting the compensatory effects o f forefoot varus. references 1. root ml. orien \vp, weed j ii. normal and abnormal function o f the foot. los angeles: clinical biomechanics corporation. 1997:46. 80. 173. 297. 329. 2. grumbine na . the varus components o f the forefoot in flat foot deformities. j.a.p.m .a. 1987: 77(1): 14 20. 3. seibel mo. foot function, a programmed text. baltimore: continued on page 11 sports medicine june 1997 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a review of sesamoiditis of the first metatarsal michael els n h d p o d (sa) intr od uction sesamoids can become tender and painful and so too the associated structures and joint complex can be affected, this is loosely termed as sesamoiditis. commonly known as the tibial and fibial sesamoids they lie in the tendon slips o f the flexor hallucis brevis tendon and underlie the first metatarsal head. these two bones have the function o f elevating the first metatarsal head, to disperse impact forces, protect the flexor hallucis longus tendon, reducing friction and allowing the first metatarsal to glide posteriorly during the propulsive phase o f gait.7 sesamoiditis is a pain syndrome becoming more common due to the increase in popularity o f sports.2 though the condition can be found in patients of any age or activity level and may present with symptoms of sudden onset, acute or chronic duration and with or without a history o f associated trauma or systemic disease. the condition can be classified as either congenital, anatomical, arthritic, infectious, systemic or ischaemic. etiology the most common cause o f sesamoiditis is repetitive microtrauma from jumping sports,2,4 such as basket­ ball, netball and in cricket bowlers, where as much as fifty percent o f the individuals weight is transmitted through the first metatarsalphalangeal apparatus. sesamoiditis is also seen in women due to wearing o f high heeled shoes which force the first metatarsal to be vertical, placing the hallux in extension which in turn fixes the medial and lateral sesamoid bases under the metatarsal.7 biomechanical derangement o f the lower limb, such as rigid planterflexed first raj’, a forefoot valgus or a foot wit h a marked talar declination angle seem to be pre­ disposed to sesamoiditis. typically a sesamoidal fracture is transverse or com­ municated and one or both sesamoids are involved." it is more common for the tibial sesamoids to be frac­ tured because o f the increased load in closed kinetic chain o f gait. these injuries should be differentiated from congenital bipartite, tripartite sesamoids which result from the incomplete coalition o f the primary ossification centres.4 '1 clinical features a localized pain on the affected sesamoid is usually’ described, aggravated by weightbearing and isolated on deep and firm palpation.3 pain could be either post traumatic or o f insidious onset. active or passive dor siflexion and planteflexion elicit pain. localized signs o f inflammation may or may not occur in the surround­ ing first metatarsaphalangeal joint. in insidious sesamoiditis the appearance o f adventitious bursitis and or hyperkeratosis underneath the first metatar sophal angeal joint.'1 there are many’ conditions which cause a simdar metatarsalgia and may be local or systemic in nature. osteochondritis or treve’s disease is avascular necro­ sis o f sesamoids showing both lytic and scleritic changes with fragmentation occurring.14 radiographic changes are not always seen with sesamoiditis and requires observation for differential diagnosis. occasionally’ sesamoiditis can produce a positive bone scan. differential diagnosis from osteo­ chondritis, fracture, infection, neuritis o f the medial plantar nerve, or bursitis. management initial treatment involves the need to relive the pressure o ff the sesamoid bone. a cushion pad with an aperture over the sesamoids and strapping o f the hallux in a planter flexed position in order to relax the tendons containing the sesamoids.3 icing, prescription o f analgesics and advice on rest and appropriate footwear. the injection o f local anaesthetic and anti­ inflammatory cortisone derivatives are o f help.4 the prescription o f a custom made innersole with a single wing plantar metatarsal pad or where required for more biomechanical correction a “ u” out slieaffer plate ortliotic to compensate for a first metatarsal equi nus.47 a plaster cast may be used to immobilize and decrease weightbearing o f the first metatarsopha­ langeal joint i f initial padding fads to reduce the symp­ toms. i f conscientious conservative treatment does not help, surgical removal may' be required. this is accom­ plished by an incision at the medial planter aspect of the metatarsal head with care taken to avoid the planter m edial nerve, a dorsal intermetatarsal approach to reach the lateral sesamoid may also be taken.s removal however results in a change o f biome­ chanics to a certain degree and the risks invalidating the function o f the short flexors which may lead to subsequent deformities. references 1. burquist th. im aging o f sport injuries. aspen 1992. 113. 2. ellis j. feet first, runners world. vol 5:2 (f eb ru a ry ): 26 1997. 3. ilela l b, wilson d. the foot. vol 2 churchill livingston 1988: 166-182. 4. jahss m. disorders o f the foot. vol 2 wb saunders 1991:134-151. 5. levy a l , iletherington jv. principals and practice of podiatrie medicine. mosby 1991,88-93. 6. noble c. the pfizer manual o f sports injuries. vol 1 medical tribune 28. 7. yale i. podiatrie medicine. 2nd ed. williams and wilkins 1974:112-115. □ 6 sports medicine june 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) excessive pronation as an etiology in patellofemoral pain syndrome darryl cohen n h d pod(sa ) patellofemoral pain is a common condition facing prac­ titioners. whilst the condition is common, it is a d iffi­ cult condition to treat, and there is no clearly defined management protocol. there are many beliefs about the cause o f patellofemoral pain, and generally it is accepted to be a condition occurring due to maltrack ing o f d ie patella. anatomy o f die patellofemoral join t in order to have a good understanding o f patellofemoral syndrome, it is vital that the anatomy o f the joint is well understood. the patellofemoral joint comprises the articulation between the femur and the patella. the patella surface o f the femur (fig 1) is situated at the anterior aspect o f the condyles o f d ie femur. it extends proximally more on the lateral side, the prox­ imal border being oblique, runs distally and medially, and is separated by the tibial surfaces by two faint grooves crossing the condyles obliquely. where d ie medial groove ceases, the patella surface continues to die lateral part o f the medial condyle as a semdunar area adjoining the anterior region o f the intercondylar fossa, this area articulates with the medial vertical facet o f the patella in lull flexion.4 surface sub-cutaneously is separated from the skin by a prepatella bursa, and is covered by an expansion from d ie tendon o f quadriceps femoris, which blends superficially with fibres o f the patella ligament.4 the posterior surface o f the patella has a proximal smooth, oval, articular area, crossed by a smooth ver­ tical ridge which fits the groove on the femoral patella surface and divides the patella into a medial and larg­ er lateral facet. both the ridge and flanking are natu­ rally protected by articular cartilage. a narrow strip, proximally broader, is marked o ff medially from the medial facet, which makes contact with the femoral condyle in extreme flexion. distal to the apex is a roughened area at the attachment o f the infrapatella tendon and proximal to this the area between the roughened apex and t he articular surface is covered bv an infrapetella fat pad. th e thick superior border as an attacliment for the rectus femoris and vastus inter medius slopes down and forward, except near the pos­ terior margin. the medial and lateral borders are thin­ ner and converge distally forming the attachments for the expansions o f the tendons o f vastus medialis and lateralis. near the superolateral angle is a shallow, cir­ cular depression for a distinct attachment o f the ten­ don o f vastus lateralis.4 p a te lla r s u rfa c e figure 1. the knee joint showing the patella surface:' (coetzee 1987) the patella is the largest sesamoid bone in the body, and its main biomechanical function is to increase the effective lever arm o f the quadriceps. this bone also centralizes die divergent forces o f the quadriceps into one tendon, namely the patella tendon, thus helping to provide stabdity to d ie knee joint." the patella is shaped like an inverted triangle (fig 2), with rounded sides. the base (proximal end) gives attachment to die quadriceps femoris muscles, and its apex (distal end) gives attachment to d ie patella liga­ ment and in turn to d ie tibial tuberosity." the anterior figure 2. a nterior and posterior views o f the patella ( gray 1989) gait as an etiology in patellofemoral pain a long distance runner's feet make contact with the groimd approximately five thousand times in an hour’s run, and thus it is vital that both their feet and lower extremities are functioning at their best.1 gait can be divided into two phases; the stance phase and the swing phase. the stance phase is fur­ ther divided into heel strike, and mid-stance and toe off. as the foot strikes the ground on its lateral aspect, d ie knee is in frill extension (fig 3), the femur and dbia sports medicine june 1997 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) are externally rotated but in the process o f internally rotating through to a quarter of die midstance phase, and the knee join t begins to move into flexion. thereafter the femur and tibia begin to externally rotate for die rest o f the stance phase.*’ as the knee joint flex­ es the compressive force o f the patellofenioral joint increases; diis may help to understand why the pain is often present when a patient rises from sitting, climbs stairs or is sitting with the knee flexed ( ‘cinema sign’).7 with the above in mind, it becomes easy to understand that if the foot pronates excessively beyond 25% o f stance phase, the tibia and femur are still internally rotated when they should be externally rotating. thus with the excessive pronation comes excessive internal rotation o f the tibia and femur, an increase in the ent­ angle. and therefore maltracking o f the patella1 (fig 4). this excessive internal rotation also causes an abnormal pull o f the quadriceps on the patella. this usually occurs as the knee flexes and the patellofemoral joint is expe­ riencing increasing compression forces. since with excessive pronation, the origin and insertion o f the quadriceps are situated lateral to the patella, the quadri­ ceps tend to pull the patella in a lateral direction.1 figure 4. the change in the q-angle in relation to the position o f the foot. illustrative case study to indicate the typical patient with this condition and the response to therapy. subject: 23 year old female presented with bilater­ al patellofemoral pain, brought on by aer­ obics. th e clarke’s test was positive and crepitus was evident and the patient was experiencing the ‘cinema sign’ . there was a quadriceps imbalance between vastus lateralis and vastus medialis. she was not responding to the mccomiel taping and exercise programme, a usually successful therapy. foot biomechanics showed a fore­ foot invertus and hyperniobility in both feet. gait examination revealed excessive sub-talar joint pronation, beyond 25% of the stance phase.the weightbearing foot as view ed on a podiascope was very planoid. treatm ent: semi-flexible moulded sports orthotics were manufactured. th ese comprised 2mm polypropylene vacume moulded to a plaster cast for specificity, with forefoot and rearfoot medial posting o f a firm eva, and an arch filler o f low density eva for cushioning. th e patient was advised on easing into the orthotics. result: within three weeks the patient was completely asymptomatic. when trying without the orthotics, the symptoms ini mediately returned. conclusion th e exact cause o f patellofemoral pain may not have been accurately identified, perhaps because there is no single cause. it is therefore vital unit, all possible eti­ ologies are considered, including quadriceps imbal­ ance which has proven to be quite successful when treated, using taping and exercise therapy by a quali­ fied physiotherapist. from the above it is also clear that in the complete treatment o f patellofemoral pain it is important to ensure that patients have had a frdl biomechanical gait assessment, and any gait abnor­ malities corrected. rcfcrcncgs 1. burchbinder mr, napora nj, biggs ew. (1 9 7 9 ) the relationship o f abnorm al pronation to chonromalacia o f the patella in distance runners. journal o f the american podiatry association 1979 vol. 69 no. 2. 2. coetzee t (1 9 8 7 ). drennan’s numan osteology qth erf. maskew m iller longman. 3. donatelli r (1 9 9 0 ). biomechanics o f the foot and ankle. philadelphia. f a davis. 4. gray’s anatomy. edited by williams pl, warwick r, dyson m, and bannister lh . thirty seventh edition (1 9 8 9 ). churchill livingston. 5. inman vt, ralston h j and todd f. (1 9 8 1 ). human walking. baltim ore williams and williams. 6. ilungerford d s and barry m. (1 9 7 9 ). biomechanics o f the patellofemoral joint. clinical orthopaedics and related research n o .244 o ct 1979. 7. noakes t. (1 9 9 2 ) lore o f running. 3rd edition. oxford university press. 8. whittle mw. (1 9 9 1 ). g ait analysis. oxford butterworth heinemann. d figure 3. position o f the knee throughout the gait cycle (w h ittle 1991) 8 sports medicine june 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) iliotibial band syndrome (itbs) in long distance runners john w pagliano dpm, ms ab s tr a c t t h is painful condition on the lateral side o f the knee was diagnosed in 4.9% o f 4,198 long distance run­ ners treated for lower extrem ity musculoskeletal complaints. many o f these runners related a sign ifi­ cant change in th eir running habits, i.e., changes in distance, speed, terrain, surface and/or training shoes prior to the onset o f their symptoms. th e mean age for athletes examined was 34.5 years for m ales and 32.6 years for females. females were found to be disproportionately high in itb s when compared to other running injuries. surprisingly, itb s cases are reliably ligh ter than other categories treated for lower extrem ity injuries. d espite the la t­ eral knee pain m ost runners were able to continue running but had their workouts and distance com ­ promised. t h ere did not appear to be any relation between itb s and valgus or varus foot types. our original study showed a correla tion between varus knee alignment and itbs. i t was rarely seen in a valgus position. once present, the symptoms often persisted from two to six months. a ll o f the runners in our series w ere treated by non-surgical measures including rest, reduction in running, anti-inflammatory m ed­ ication, local steroid injections, new shoe gear and/or orthoses. shoes did not seem to be a contributing factor but we feel the use of a well-cushioned training fla t with a good heel counter is essential for controlling this problem. iliotib ial band syndrome (it b s ) is one o f the more common injuries among long distance runners. w ith the advent o f jogging and com petitive running over the past several years this syndrome has becom e more w idely recognized. 1-340-7-8!) ilio tib ia l band syndrome has been classified as an overuse injury developed by rep etitive movement o f the ili­ otibial band as it slides over the prominent margin o f the lateral femoral condyle as the knee flexes and extends.27 it occurs in approximately 5% o f all run­ ners treated for musculoskeletal complaints. t h e iliotib ial band its e lf is a thickened strip o f fascia lata that extends from the iliac crest to the lateral tib ia l tu b ercle (g e rd y ’s tu b ercle ) and receives part o f the insertion o f the tensor fascia lata and gluteus maxitnus. with flexion the tensor facia lata pulls the band anteriorly and with extension the gluteus maximus shifts the band posteriorly.2 a t the ltnee join t the band acts as a stabilizing ligam ent between the femoral condyle and the tibia. evans believes that because it crosses two joints its effect on the knee varies according to the position o f the hip. to achieve maximum stability in standing the it b locks the ltnee into extension and con­ tributes to pelvic slouch by its action on the hip. evans also believes the it b enables us to rest w hile standing and that it appeared phylogenetically with the developm ent o f upright posture. as the knee flexes and extends during athletic activity, the iliotibial band rubs over the lateral fem oral condyle and an inflammatory condition is produced. t h e pain is usually localized above the knee join t but can extend up the lateral side o f the leg. orava,4 in cadaver dissection, has found a reddish brown bursal thickening under th e itb in the vicin­ ity o f the fem oral condyle. h e states that this con­ dition is the result o f the iliotib ial band rubbing over the femoral condyle. i f one we re to walk s tiff legged, the condition would not be as pronounced as th e band no longer rubs over th e epicondvle. running, clim bing stairs and deep squats aggravates the condition. our original study o f 84 patients with iliotibial band syndrome showed that the age ranges from 15 to 63 years o f age with a m edian age o f 33.9. o f those, 56% were men and 44% w ere women. th is contrasts with our original prediction o f 70% male and 30% female. we feel that there is a greater than expected number o f women with itbs and is th ere­ fore a gender-related running injury. o f those 83 patients seen with itbs, 32 (33%) had right knee involvement, 38 (46%) had left knee involvement, 13 (16%) had bilateral involvement and one case was not recorded. th is shows a higher than predicted value for the left knee. we had expected only 32% to have left knee involvement and 31% to have bilateral involve­ ment. i t is difficu lt to draw a conclusion on this ev i­ dence. a ll o f the runners examined wore shoes that were designed for running. ten differen t brands were worn and 90% wore one pair o f socks. clinical histories revealed that the majority o f the patients with itb s ran less than 62 ion per w eek (table 1) and had running between one and five years with an equal number over five years. (table 2) m ore injured runners w ith itbs than control run­ ners with other injuries ran between 32-621tm. table 1 proportions o f runners with itbs or with after injuries who ran different distances km % control group per week with itbs with (%) other running injuries 1-32 38 45 32-62 48 34 63-94 14 14 95-126 4 5 127+ 1 2 sports medicine june 1997 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table 2 running experience o f runners with itbs experience level proportion o f runners (%) less than 3 months 3-6 months 6 months to 1 year 1-5 years 5 years+ most limners failed to seek medical care until the severity^ o f the pain had reached levels where their workouts would be compromised or terminated due to increased pain levels. (table 3) symptoms often persisted two to six months but some runners ran with the condition for more than two years. usually, once the condition was corrected, it very rarely returned under careful athletic guidelines. examination o f training records indicated that the pain was aggravated by repetitive movements such as running, climbing stairs and squatting. the patients could generally walk for long distances but were lim it­ ed in their running activities. diagnosis was somewhat complicated but usually confirmed by tenderness elicited by palpation o f the area o f the lateral femoral epicondjle. usually the popliteal tendon, lateral collateral ligament, anterior lateral fat pad, lateral joint line and patellar tendon were not tender to palpation. joint masses and cystic masses were ruled out. clinical examination revealed that the patient could jog in place and hop without significant discomfort. there was no ligamentous laxity and anterior drawer, pivot shift or jerk tests, and mcmurray’s test were also negative. renee’s “ creak” sign was also absent while palpating the lateral aspect o f the knee. in most cases tliere was a neutral knee alignment or varus knee alignment. very few had a genu valgum deformity'. in our initial study’ we found that the longitudinal arch structure was normal in the majority o f runners while nine had pes planus deformities and 11 had high arches. seven o f the 48 original study patients were wearing orthoses, four rigid and three flexible, before the onset o f symptoms. x-rays usually showed no degenerative changes or prominent ridges. in examining training programs9 we found that most patients had made a significant change in their run­ ning schedule, either in time or distance. the addition o f interval work was also reported. the addition of hilly terrain was also implicated and a lew patients stated that they had changed from a soft running surface to a hard running surface when the symptoms appeared. treatment included reduction o f distance and speed. we wished to treat most oi our athletes i>y noil surgical methods and rest was our treatment, o f choice. we advocated the application o f moist heat on a daily basis. the use o f a pro knee sleeve appeared to stabi­ lize the outer knee area and to provide heat to the knee area. this also limited the athlete in squatting and stair climbing activity. a local steroid injection was o f help in some cases. th e patients were allowed to return to running on an asymptomatic basis with the addition o f proper training shoes and a softer running surface such as packed grass or dirt. no single treatment seemed better than others. we used a “ mixed bag” o f treatments to m eet the patients’ desires and patience. orava recommends the use ol topical vasodilatory agents but these were not used in our population. noble, described a surgical technique used in nine o f his 220 patients who did not respond to conservative treatment." h e transversely split the posterior 2.0 cm o f the iliotibial band at d ie area o f the lateral femoral epicondyle so that a portion.of the band was not taut at 30 degrees o f flexion. h e did not believe in excision o f the prominent ridge. only two runners in our series did not respond to conservative treatment but surgery' was not elected in these patients. the higher degree o f left knee injury may indicate tli at. running on a sloped terrain or on the crown o f the road mav cause some friction on the knee rather than on a flat surface. the syndrome was usually seen in ectomorphs and mesomorphs and was generally absent in endomorphic populations. this may be due to the higher percentage o f fat deposited around the knee area. it was more common in those running between 20 and 40 miles per week and in those who had increased their mileage and speed prior to onset o f symptoms. increasing the mileage was the most often noted change. obviously, one has to run a certain distance in order to incite and sustain an inflammation reaction o f the lateral femoral epicondyle. most could run with pain, but they usually ran fewer hills and reduced both mileage and speed. as in most studies, there are probably a great number o f subclinical cases in which the patients adjust their own schedule without seeldng medical advice, and the condition may spontaneously improve. a specific brand o f shoes could not be implicated in causing symptoms. but three patients did note a recent change in shoes and an additional three described running on vvom-out shoes. one patient did not experi­ ence symptoms until he began adding glue to the bottom o f his shoes. (the role o f footwear may be a contributing factor in certain cases but in our sampling this was not apparent.) it does not appear that foot structure is a significant contributing factor. a cavus foot may result in a more varus stress on the knee but this is speculative. some patients could participate asymptomatically in other 4 2 16 38 40 table 3 severity o f pain at time o f seeking medical care in runners with itbs severity' o f pain proportion o f runners (%) pain only after running pain before, during and after run­ 8 ning 23 workout compromised by pain 52 unable to work out 17 10 sports medicine june 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports, i.e., racquetball, softball and basketball without pain. the}experienced pain only with sus­ tained running and constant repetitive knee move­ ment. the differential diagnoses should include tom lateral meniscus, capsular and ligamentous tears and avulsions, discoid meniscus, pseudogout and chondromalacia patella or popliteal tendinitis. synovial plications in our experience have not been symptomatic on the lateral side o f the knee with running. th e long-term prognosis for iliotibial band syndrome appears to be good, although some patients had recurrent symptoms i f they did not follow proper guidelines. although there are many types o f treatment for itbs, we have broken our treatment regime into the following: 1) rest 2) physical therapy modalities 3) anti-inflammatory medications 4) local steroid injections 5) foot orthoses 6) knee stabilizer 7) topical vasodilatory' agents (orva) 8) training flats 9) asymptomatic exercise 10) surgical physical therapy modalities were prescribed on an every-other-day basis or three times weekly. moist heat was applied on a daily basis either at the physical therapy facility or at home. this was applied with a moist pack or whirlpool, 110 degrees for 20 minutes. th e purpose o f the moist heat is to reduce pain, reduce spasm, increase blood flow, reduce joint stiffness and to increase collagen extensibility. electrical stimulation or h-wave is used to reduce muscle atrophy, reduce spasm, reduce edema and reduce pain. therapeutic measures also include soft tissue mobilization to include massage or musculofascial release. stretching may include proprioceptive neurofacilita tion and passive massage. perhaps the most effective is ultrasound, applied directly at 7.5 watts/cm2 for seven minutes. the use o f a good, stable training shoe on a level surface is recommended. shoe selection w ill be discussed in the oral presentation. i recommend the use o f a good warmup prior to the running workout. this may include a one-half mile walk. ice may be applied briefly after the workout. references 1. renne j. the iliotibia l band friction syndrome. j bone join t surg 57:1110-1111, december 1975. 2. kaplan fb. the iliotibial tract: clinical and morphological significance. j. bone joint surg. 40:817-832, july 1958. 3. evans r the postural-function o f the iliotibial tract. ann coll surg engl 61:271-280. july 1979. 4. orava s. the iliotibia l tract friction syndrome in athletes an uncommon exertion syndrome on the lateral side o f the knee. br. j sports med 12:69-73, june 1978. 5. smillie is: injuries o f the knee joint, ed 4 london, churchill livingstone, 1973, pp. 357. 6. noble ca. the treatment o f iliotibial hand friction syndrome. br. j sports med: 13:51-54, june 1979. 7. pagliano jw. a clinical study o f 3000 long distance runners, american college o f sports medicine, annual meeting, san diego, ca, 1984. colloquin presentation. 8. brody d. c ib a , volume 32, november 1980. 9. sutker a n . jackson dw, pagliano jw: iliotibial band syndrome in distance runners. physician and sports medicine 9:69-73, october 1981, mcgraw-hill, inc.ends □ continued from page 5 williams and wilkins, 1988: 166 179, 226 227. 4. tax iir . podopediatrics. baltimore, williams and wilkins, 1988: 166179, 226 227. 5. subotnick si. sports medicine o f the lower extremity. new york, churchill livingston, 1989: 167 168. 6. mcglamry ed, banks a s. downey ms. comprehensive textbook o f fo o t surgery. vol. 1 2nd ed., baltim ore, williams and wilkins, 1992: 776, 821. 7. r oot ml, orien wf, weed j ii. biomechanical examination o f the fo ot. los angeles, clinical biom echanics corporation. 1971: 72. 8. werniclc j, langer s. a practical manual fo r a basic approach to biomechanics. new york, langer acrylic labo­ ratory. 1971: 10-20. 9. jahss m il. disorders o f the fo ot. vol. 1. 2nd ed. philadelphia, wb saunders company. 1991: 472 474. 10. thomson p. introduction to podopaediatrics. london, wb saunders company. 1993: 56, 206. 11. boyed pm , neale d, rendall g. the adult foot. in: neale d. ed. common fo o t disorders. 4th ed. london, churchill livingston. 1994: 54, 58. 12. jones u , todd wf. abnormal biomechanics o f flatfoot deformities and related theories o f biomechanical develop­ ment. clinics in podiatrie medicine and surgery. vol. 6 .(3 ). 1989: 517. 13. philps jw. the functional foot orthosis. 2nd. ed. singapore, churchill livingston. 1995: 8, 9. 14. yale i. podiatrie medicine. 2nd ed. baltimore, williams and wilkins. 1980: 280. 15. spencer a m . practical podiatrie orthopedic procedures. ohio, ohio college o f podiatrie medicine. 1978: 54. 16. o ’donnell m a. a prevalence study of f orefoot varus, fore­ foot valgus, rearfoot varus and rearfoot valgus in six to eight year old children. fv international congress o f podia­ try, london, may 1995. 17. menz h b . clinical hindfoot measurement: a critical review o f the literature. the foot. vol. 5 (1 ). 1995:59,62. □ sports medicine june 1997 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a podiatric approach to common lower extremity injuries in cycling philip a carstens (nd. p o d s.a.) the modem day podiatrists importance and input to cycling is not a superficial interest, but it becomes a sci­ ence to improve performance, prevention and treat injuries, correct techniques and to give a vital service to research and data on this neglected but growing field of sports medicine, especially in tiiis current competitive and professional sports era. the most important feature o f a bicycle is how it fits the rider.” performance, comfort and the risk of injury can be affected by variations, some­ times as little as 5mm in the riding position. the gener­ al belief is that cycling is a harmless, innocuous and low impact activity. bicycliug is actually a very popular aero­ bic exercise that can be harmful i f not done properly with the correct equipment, settings and under supervision. cycling is a favourite prescription for the rehabilitation o f certain post-surgical conditions when the patient is not able to do other exercises. it can however lead to overuse injuries o f the lower extremities (including the lower back) due to improper settings, biomechanical malalign­ ments and wrong riding techniques. when treating a patient with an injury caused by cycling, it is important to determine whether it is the patient’s primary sport and what type o f cycling is exer­ cised, e.g. mountain biking, racing, track, touring, train er(rehab.) or triathlete biking. some key questions are: 1. what type o f cycling is exercised? (to determine equipment and terrain) 2. a t what rate do you pedal? (ideally between 70-110 r.p.m.) 3. what type o f shoe is used? (cycling shoes are cur rentiy categorised into cleated, clip’s, mountain bike and touring, although several o f the categories may overlap.) 4. do you use cleats, toe clips or clipless pedals and what type? (this determines what position the foot is kept in) 5. do you know your knee position on your bicycle at 3/6’0 clock respectively? (it shows quicldv i f the seat height or position must be adjusted) before you can proceed to making any diagnosis and pre­ scribe treatment you must have knowledge of the follow ing:1. the anatomy o f cycling a general description of the anatomy involved is a basis for understanding the general injuries and the prevention o f these injuries. the anatomy mainly involved is the muscles and joints o f the neck, back, arms, pelvis,legs and feet. this varies in degree from regions during specific move­ ments. the quadricep and gastroc-soleus muscles are o f the main power suppliers and the knee and subta­ lar joints are o f the most importance, their strength and flexibility can prevent knee and lower leg injuries.5 (fig 1) aspect. 2. cycling biomechanics during a pedal cycle, the foot moves from top dead centre (tdc=0) to bottom dead centre (bdc=180) and proximally back to tdc. as with the closed kinetic chain gait cycle, a change in a joint angle gene rally affects the joints distal and proximal to it because o f the ground foot-leg-thigh linkage. cycling has the same chain, except the foot is fixed on the pedal, and there is no heel contact. minimal metatarsophalangeal joint motion is allowed because the rigid cycling shoe is fixed to the pedal. a remarkabfe difference between gait and cycling occurs in the phase where maxi­ mum pronation corresponds respectively to a dorsi flexed and plantarflexed ankle. as the foot enters the power phase o f the pedalling stroke, the ankle plantarflexes, the knee extends and the tibia medially rotates. this everts the calcaneus, pronates the subtalar joint and unlocks the mid tarsal joint. 3. proper settings o f a bicycle machines such as the elite (fig 2), the fit kit, and serotta size cycle, and specialised computer programmes such as probike fit can be used. in practise it is mainly done manually the vital factors in sizing are saddle height (fig 3), the length o f the top tube, amount of seat post exposed when saddle height is correct, the clearance between your crotch and the top tube. relative to height, women generally have shorter torsos than do men. sizing a woman’s bike by inseam length and seat tube size can often result in too long a top tube. the best is to have a longer seat post and smaller bike frame. childrens fit­ ting is done by wheel sizing. these factors will vary slightly depending on the cycling activity and the patient’s physique. physical examination 1. standard biomechanical assessment, checking head, shoulders, torso, pelvis, hips, knees and feet positions, 12 sports medicine june 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) motions, lengths and alignments.'4 doing measure­ ments to determine any degree o f abnormality, in particular genu varum or valgum, external or internal tibial torsion.(fig 4a & 4b) 2. on bilte, riding assessment it is advisable to use a video camera for playback i f you are not familialwith cycling bio mechanics and also to compare alter settings and adjust­ ments have been made. place the patient on a trainer using his own bicycle and marking die tibial tubercle clearly with a blight coloured koki pen. video shooting must be done from the front, sides and rear. the patient should cycle ± 2min. at between 70-110 rpm pedal cadence oil a high gear. from the front the ftnees should move straight up and down." as die foot pronates, the knee often moves medi­ ally towards the top tube during die power phase, and lat­ erally during pull up. from the rear the legs should move straight up and down with both feet fixed on the jjedals with minimal in-out toe movement and die buttocks must stay in the same seat position with no rocking of die hips.7 from the side with the foot in die top dead centre posi­ tion, die ltnee ideally is flexed approximately 100 to 110 degrees and the ankle is slightly dorsiflexed or 0 degrees. the ball o f the foot should be on the axis o f die pedal when the loot is in the 3 o’clock position with the ltnee in a plum line position to it (fig 5). once die foot reaches bot­ tom dead centre die knee ideally is extended to about 160 165 degrees, the ankle is maximally plantarilexed and the foot in supination. determine i f any abnormality can be detected and if; adjust die settings accordingly. common injuries many biomechanical problems can lead to injuries, even with the bicycle properly positioned. most lower extremi­ ty injuries occur during the powder phase when die foot moves from top dead centre to 120 degrees, vvidi the peak­ ing o f force at 90 degrees. simple strains o f the dioracic paravertebral muscles or lumbosacral paravertebral muscles can often be alleviated by shifting position, moving the seat forward (or back­ ward) on its mount or varying the lengdi o f the handlebar stem. the lower back is also at risk o f pain due to the bent over position. knee pain is the most common injury in cyclists.'1 i t is usually caused by chondromalacia patellae, but can include patellar tendinitis, bursitis, and nivotendinitis quadriceps (where it inserts into die superior aspect o f the patella.)8 (fig 6) the quadriceps provides die power in cycling and also the area most often injured in a bicycle crash usually with contusions. these injuries should be treated with ice, massage and immobilisation o f muscle action to prevent myositis ossificans. often the rider is to blame for the ltnee pain in that the seat is too high or low. i f too low7, the ltnee flexed too much at die area o f most force in the down stroke, generating excessive pressure across die patellofemoral joint.' from lull extension to lull flexion o f the knee the patella glides caudally ± 7cm on the femoral conchies. both die medial and lateral lascets of the femur articulate with the patella from full extension to 90 degrees o f flexion. beyond 90 degrees o f flexion die patella rotates externally, and onlv medial femoral facet articulates with the patella. a t full flexion the patella sinks into the intercondylar groove.(fig 7a & 7b) sizing frame: adjustable for p r o p o r t io n a l tu b e le n g th s .# figure 2>. example of the e lite size cycle. sports medicine june 1997 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cleat placement can also put cxcess strain 011 the knee. cleats lha( are adjusted too far outwards cause prcssiu'c placement on the outside o f the knee and loo much inwards 011 the inside o f the knee. shoes should be adjusted such that the metatarsal heads (wider part o f the loot) are placed directly over the pedal spindle, (women need a little more inward tilt to account for wider hips.) knee pain can also be caused by pushing gears that are high. when cranking along slowly in a high gear, at low cadence the rider is getting more force across the patellar femoral joint. pronation can lead to pain, mostly in elite riders or riders cycling in sneakers or running type shoes, allowing more subtalar joint motion because of the lack o f rigidity. this can lead to knee and other pronatorv type injuries like posterior tib ial tendinitis, plantar fascitis, bursitis neuroma type and soft tissue pressure injuries, including toenail problems. orthotics can be used to correct these problems," but arc different to running type orthotics because they do not fit well in the shoes and there is no heclstrike or stance phase in cycling. riuining type orthotics arc designed to work during heel strike and toc-off. good results can be achieved with a variation o f forefoot wedging or cleat adjustment in cyclists. some canting can be done lmdcrncath the cleat, although with some newer pedal systems it becomes impossible. orthotie control must be applied to the forefoot, even in the absence o f a measurable forefoot deformity. orlhotics must be very specific for sports that require no or little metatarsophalangeal motion such as cycling, skiing or skating.7 preferably the forefoot posting must be placed cxtrinsically and is extended beyond the metatarsal heads to the sulcus o f the toes. this will give good forefoot control. a dense rubber material can be used for (he posting and the orthot.ie must fit prop­ erly in the shoe. i f the shoe becomes too narrow the patient might have to change to a different shoe. it is important that the amoiml o f forefoot posting equals the amount o f posting that would normally have been used in the rearfoot, plus the ainoiuit that is required in the forefoot. a biopedal can also be used to correct various discrepancies.7 the gastrocnemius solcus muscle is another power source. tears will result in pain upon plantar flexion o f the foot. (fig 8) cyclists with achilles tendonitis must avoid [lulling up dm ing the passive phase. ii severe, apply r.i.c.e. and physical therapy. to prevent one can wedge the heel; stretching exercises; strapping and the use o f anti inflammatorics." complete rupture rarely occms during cycling. traumatic injuries knowledge o f first aid is required and proper woimd cleaning techniques must be applied. numbness is a common complaint affecting the hands, feet, genitals and buttocks area. numbness to the genitals and hands is very common and is referred to as cyclist’s palsy. the cause for affecting the genitals is compression o f the pudenal nerve. the saddle type; height; position and tilt must be checked and correct­ ed. padded cycling pants must be worn. numbness in hands and feet can be due to cold and exposure or too narrow and tightly fitting shoes; toe clips; gloves or too light a grip. treatment involves changing to the right shoe size, gloves, and keeping the hands and feet warm. regular movement o f the lingers and toes will allow for increased circulation. c o n tin u e d on p a g e 10 figure 5. k n e e p o s itio n o v e r ped a l spindle, w ith cra n k a t 3 o ’ clock. figure 6. types o f e x tra -a rtic u la r in/luinm ation sites o f the knee. figure 8. in/lamed a c h ille s tendon. 14 sports medicine june 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) glenbarr pecialist publication so u t h a fr ic a n j o u r n a l of sp o r t s medicine vdi 3 no 2 july 1996 o p ^ t t q j glenbarr publishers private bag x14, parklands 2121. tel: (011) 442-9759 fax: (011) 880-7898 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) enrollment form i am interested in attending the first south african podiatry congress on october 4, 1997, at the volkswagen conference centre, midrand. first name: surname: ... title: ......... address:.... code: .. fax: .tel: .................... if you wish to present a paper, please send your resume and presentation to the s.a.p.a. executive p.o. box 1011 rosettenville 2130 to arrive not later than september 1, 1997. assisted travel for accepted papers. cost s.a.p.a. member non-s.a.p.a. members receipt given on request. only cheques or postal orders. all payments to be made to podiatry association. i enclose my cheque of r ........................... post to. mckenzie dickerson int. p.o. box 53101 troyeville 2139 tel: (011) 402-3240 • fax: (011) 402-0164 final programme will be posted to all dele­ gates august/september. r100,00 r140,00 the s.a. continued from page 14 references , 1. ronald l. valmassy. clinical biomechamcs o f the lower extremities. mosby, 1996: 453-454. 2 margareta nordin, victor h. frankcl. basic biomeehanics of lhe musculoskeletal system. 2nd edition: lea & felnger, 3 j e ffi-e ^ m . robbins. clinical handbook o f podiatrie medicine. volume 1. ohio college o f podiatnc medicine, 1983: 16-37. , , , 4. sheldon langer, justin wernick. a practical manual fo r a basic approach to foot biomechanics. the langer foundation for biomechanics and sports medicine research, 1990: 6-8. the south african podiatry association the first south african podiatry congress o ctober 4, 1997 volkswagen conference centre m idrand 08:00 18:00 o v e r 20 s u pplier exhibits fo r the p odiatry profession refreshments & 4 -course lu n c h best paper award congress organized by mckenzie dickerson international 6. 8. 9. stanley hoppenfeld. physical examination o f the spine and extremities. appleton-century-crofts, 1976:176. steven i sidyotnick. sports medicine o f the lower extremity. churchill livingstone, 1989: 314. 638-639, 643-644. ayne furman. lower extremity overuse injuries in cyclists. foot & leg fiinction. volume 2 no. 2, june 1990: 1-4. sandra adams eisele. a precise approach to anterior knee pain. the physician and sportsmedicine. volume 1j, j\o.b, june 1991:128-137. richard bailantine, richard grant. richard s ultimate bicy­ cle book. dorling kindersley, 1992 :20-21,116,162-163. david. m.brody. running injuries. clinical symposia. ciba. volume 32, no. 4. 1980. 21. , 11. bob prichard. screen test. bicycling. 136-13j. u 10 16 sports medicine june 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial ln this issue we focus on issues encountered by teams travelling to compete overseas in international competi­ tion. dr wavnc diesel, chief physiotherapist for the south african olympic team at the 1996 olympic games at atlanta an event which lie describes as the greatest experience of his life and one that he woidd highly recom­ mend to anyone has kindly co-ordinated contributions form physiotherapy colleagues who work with our national cricket and soccer teams. together with his own contribution these articles provide an interesting insight into the role of the physiotherapists who travel with national teams. this issue is rounded off with contributions from judith johnson, a dietician in private practice who discusses: nutritional challenges for olympic athletes and by professor tom redly and his colleagues who discuss jet lag. professor reilly from liverpool is one of the leading authorities on jet lag and the co-author of the definitive book on the topic. his contribution explains the physiological basis for this complex condition and provides prac­ tical ways in which the negative effects of this condition on athletic performance, might be reduced. travelling with international teams is perhaps the greatest challenge to any professional involved in sports medicine and sports scienccs. hopefully, the expertise shared in this issue of the journal will further enhance the quality of services we can provide to our teams travelling to international competitions. professor tim noakes editor my thanks to the editors of the south african journal of sports medicine for affording me the honour to be guest editor of this issue of your journal. i would like to introduce this issue by paying special tribute to all my colleagues who have worked tirelessly, and often very much behind the scenes to entrench the role o f the physiotherapist in sports medicine. the fruits of our efforts can be seen from the fact whereas no physiotherapists travelled with our team to the 1992 barcelona olympic games, a contingent o f 5 south african physiotherapists was present at the atlanta games. this change has occurred because of calls by both the athletes themselves as well as the sports administrators to include physiotherapists in the team. clearly the athletes and administrators would not have requested our presence had it not been for the excellent work done by our profession in the handling of sports injuries at all levels, including those that occur to our elite athletes. working and travelling with sports teams appears both glamorous and a wonderful way to see the world. the physiotherapists who have contributed to this edition have all toured extensively with the most prominent of our national sports teams. in our articles we share our views on some of the pro’s and cons of travelling with our respective national teams. craig smith was perhaps the first south african physiotherapist to work with a national team. he was appointed to the national cricket team for their first tour to india in 1991; he has been a consistent and important member of that team ever since. david becker and steve felsher have worked with our soccer world cup hopefuls, the bafana bafana for some years and will likely have the experience of their lives at the world cup in france in 1998. i, on the other hand had the huge honour of heading up the physiotherapy teams to the 1995 all african games as well as the 1996 olympic games. having read these articles i can certainly relate to both the rigors and delights of travelling with a sports team as their physiotherapist. a message to those physiotherapists contemplating getting involved with a sports team: “ should you be given the opportunity to become involved, grab it with both hands. don’t seek the limelight and your rewards will come from the appreciation and performances o f the team. and perhaps most importantly, do it because you enjoy it!” gel n relief wayne diesel guest e ditor sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ■ m e t a m a x a complete metabolic system for all applications portable v 0 2 max the metamax ergospirome try system makes it possible to test a person in places where it was until now, impossible. at 1,8 kilograms using a specially designed backpack the metamax can be carried by persons to obtain measurements under real conditions. data can be transmitted to a pc via telemetry or stored for further analysis in its data logger. it can of course also be used stationary in a lab. exercise testing the metamax system allows you to measure simultane­ ously all cardiac and pul­ monary data. including o2 consumption, co2 output, temperature and pressure, ecg, heartrate, spirometry, blood pressure, skin temper­ ature and calorimetry. advanced software running under microsoft windows displays the captured data graphically and numerically and allows for personalised reports. hilhorst instruments cc phone 021 524 806 e-mail,: hilhorst@iafrica.com we also supply: woodway treadmills, lode ergometers, cardio perfect ecg systems r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:hilhorst@iafrica.com .......................................... ..... v o l u m e 4 editors p ro f td noakes d r m p schivellnus editorial board d r m e moolla dr p de jager d r j skowno dr p schwartz p ro f r stretch d r c de ridder p ro f b c andrews d r e w derman m r r h farman dr r h mars d r c a noble international advisory board lyle j micheli associate clinical professor of orthopaedic surgery boston, usa chester r kyle research director, sports equipment research associates california, usa p ro f h c wildor hollmann president des deutschen sportarztebundes kohi, west germany howard j green professor, department of kinesiology ontario, canada george a brooks professor, department of physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke associate professor, biology department, university of colorado colorado, usa graham n smith physiologist glasgow, scodand num ber 3 septrmrfp 1 9 9 7 contents editorial w diesel travel and body clock disturbances j waterhouse, t reiuy, g atkinson travelling with teams w diesel 10 the sa cricket team the physiotherapists 14 viewpoint c smith physiotherapy in south african soccer d becker, s felsher 18 nutritional challenges for olympic athletes 20 a review article j johnson hie editor the soutfi african journal of sports medicine p o b o x 115, new lands 7725 production andrew thomas pu b lish in g glenbarr publishers cc private bag x i 4 parklands 2196 tel: (o i l ) 442-9759 f ; l x : ( o i l ) 880-7898 a d v e r t i s i n g marika de waal/andrew thomas reproduction output reproduction pr in tin g ince o n t h ^ n relief editors, the advertisers or the pubhsheis “ t " 0t necessarij>' shared by die ----------------------------------------‘_________________ • reproduced without the written consent of the publishers. sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) travel and body clock disturbances j. waterhouse, x. reilly and g. atkinson r _ . , t. » t t t t school o f h um an sciences, liverpool john moores university, liverpool, u k is explained. introduction competitive sport is now recognized on a global scale and people at many levels, from the olympic games’ athlete to the recreational runner, have the opportuni­ ty of competing abroad. travelling to strange places for purposes of competing in sport might seem attractive; in reality it makes great demands on team managers, coaches, and athletes, irrespective of a trip abroad for a single competition or preparations for a prolonged tour. problems are encountered as a result ot crossmg time zones which are very different in nature from the ‘travel-fatigue’ after flying north or south, or after long journeys in cars or buses. regular walks on the plane, some stretching and static exercises will all help in minimizing this form of fatigue during this latter type of journey, and a refreshing shower or a good night’s sleep will be totally restorative. this is not the case after quickly crossing time zones, either coast to coast in australia or north america, across europe or asia, or trans-oceanic flights. then the problem is longer lasting and called ‘jet-lag’ . it has been described recently by reilly et al.1 it is based upon abnormal tim­ ing of circadian rhythms, described extensively by minors & waterhouse,2 the importance of these to ath­ letes being reviewed by atkinson & r eilly3 the present review concentrates also on counter measures that can be used to minimize the detrimental effects of jet-lag. the problem time zones because the earth is spinning on its axis, for anybody standing on the earth’s surface the sun rises in the east and sets in the west and is at its highest point in the sky at noon by local time. these events must occur in the uk after they have taken place in countries to the east and before they have taken place in countries to the west. in order to resolve this problem, the world has been divided into 24 time zones centred around greenwich and separated by lines of longitude 15 apart. these time zones determine the relationship b e t w e e n greenwich mean time (gmt) and local time, those to the east of the uk being advanced and those address correspondence to: g. atkinson phd, school of human science, liverpool john moores university, mountford building, bvrom street, liverpool l3 3af, uk. tel: +44 151 231 2376; fax: +44 151 298 1261 to the west being delayed. consequently, at the same moment it might be mid-day in the uk but, by local time, 16h00 hours in afghanistan, 21h00 hours in japan, 07h00 hours in new york and 03h00 hours in los angeles. travelling to the east, therefore, means you ‘lose time’ (in the sense that part of the day appears to have been lost), and to the west that you gain it (in the sense that you can relive some hours). for the seafarer or passenger on a cruise liner the biological implications of time zones are not very important. the rate of travel and of crossing time zones is slow enough to be accommodated easily sailing to new york, for example, entails putting the clock back 1 or 2 hours per day; in effect the traveller who stays up late may have a lie in and still be on schedule by changing to local time. jet-lag by contrast, problems arise when you cross several time zones in a short space of time. jet travellers suf­ fer from a combination of symptoms, collectively known as ‘jet-lag’. the symptoms vary between indi­ viduals in details o f their nature and severity, but include some or all of those s h o w n in box 1. jet-lag is accompanied by a general malaise, a sense of feeling and acting ‘below par’ . this is especially important in athletes who generally want to maintain their training habits or continue a systematic build-up for a forthcoming contest. r only a few studies have dealt specifically with sports performance after time zone transitions. | studies upon rugby players and american footballers j indicate a poorer performance in the days immediatej ly after the flight, particularly if the match was played i during the night in the visitors’ home time zone. such effects are important for serious competitors and agree with results from closely controlled laboratory simula­ tions of time-zone transitions. these simulations and , field studies show that there is a loss of sleep and a general decline in motivation and physical and mental , performance in particular, the normal daytime peaks i are blunted. the severity of jet-lag symptoms is greater after eastward compared to westward flights, the syndrome affects the old rather more than the young, and depends on the number of time zones crossed rather than the distance travelled. as a rough guide, jet-lag lasts, in days, up to the number of time zones crossed after an eastward flight and about half of the number after a westward flight. the severity of the symptoms may be related to menstrual cycle phase. disruptions of the menstrual 4 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cycle in female travellers have been linked to distur­ bances in melatonin secretion. higher melatonin levels in the scandinavian winter compared with summer values have an inhibiting effect on lutenizing hormone. as a consequence, ovulation might not occur during that cycle.' the extent to which the menstrual distur­ bances accompanying travelling across multiple time zones in themselves alter athletic performance is uncertain. as well as time-zone transitions, there are other changes that are associated with a long-haul flight, amongst which are: 1. a change o f customs, including food 2. the personal discomfort associated with travel 3. the loss of sleep caused by the flight schedule 4. anxiety owing to the sports meeting in the new time zone. box. symptoms associated with the phenomenon o f jet-lag fatigue during the new daytime, and yet inability to sleep at night. decreased mental performance, particularly i f vigi­ lance is required. decreased physical performance, particularly with regard to events that require stamina or precise movement. a loss of appetite, coupled with indigestion and even nausea. increased irritability, headaches, mental confusion and disorientation. these factors contribute to the general disruption, but most are essentially over within 48 hours. by con­ trast, jet-lag can last for 5 days or longer. additional reasons why the above factors are not a sufficient explanation of jet-lag are: a. the problems arise also when returning home. b. the problems do not arise when flying a long way south but without crossing many time zones, from london to lagos (nigeria) for example. c. the problems do not depend much upon whether it is a day or night flight, i.e. the amount of sleep lost during the flight. d. the problems depend far more upon time zone changes rather than culture changes (compare flights from the uk to new zealand and central africa, for example; jet-lag is far worse after the former flight). e. the problems can be reproduced in laboratory based experiments. in this case, none of the other factors applies; the only change is in the local time. these findings, particularly (e), and all other stud­ ies on circadian rhythms, confirm the view that jet-lag is a function of the abnormal relationship between the new local time and body time. such problems will per­ sist until the individual has synchronized fully to the new time zone. the body clock a large amount o f experimental data12 indicates that humans possess a ‘body clock’, located in the ase o f the brain. this is responsible for adjusting our physiology and biochemistry to the normal pat­ tern ol daytime activity and nocturnal sleep and recovery. the clock achieves this by exerting effects throughout the body via controlling the nervous sys­ tem, hormones and body temperature. as a result of its actions, the body clock causes mental and phys­ ical performance, alertness and motivation to be high in the daytime, and it facilitates getting to sleep and remaining asleep during the night by reducing most neural activity, body temperature and adrenaline secretion. importantly, it also helps to prepare for sleep at night and activity during the daytime by initiating the changes in physiology and biochem istry an hour or so beforehand. this drowsiness is promoted in the evening before sleep onset, and adrenaline and body temperature rise in the morning before waking up. three properties o f the clock are important. first, it is an inexact timekeeper, tending to run slow with a period greater than 24 hours (this is why we tend to go to bed later and have a lie-in in the mornings at weekends and during holidays). second, and related to this, it is normally adjusted to an exact 24-hour period by several rhythms in the environment. in humans in industrialized soci­ eties these rhythms are much influenced by social norms and include light/dark, feeding/fasting, social interaction, mental and physical activities. the third property of the body clock that is impor­ tant is that it is slow to adjust to changes in our lifestyle. this resistance to change is normally ben­ eficial, since it means that the body clock does not adjust inappropriately. for example, i f we go to the cinema in the daytime, the clock does not adjust to the ‘night’ nor does it adjust to the ‘day’ i f we get up to have a snack at night. this inertia o f the body clock, which is beneficial in these circumstances, is inappropriate after a time-zone transition. there will be a mismatching between body time and local time as illustrated for a subject who has just flown eight time zones to the east (table 1) and this is the origin o f jet-lag. table 1 mismatching between local and body times immediately after a flight from uk to hong kong new local time requirement body time desire 0800 hours waking 2400 hour going to sleep 1600 hours peak activity 0800 hours beginning to wake 2400 hours retiring 1600 hours peak activity when the circadian rhythms o f body tempera­ ture, physical and mental performance are consid­ ered, then they show this effect clearly.8 thus, in the above example o f an eastward flight across eight time zones, minimum body temperature tends to fall near midday local time and the maximum body temperature during the night (instead o f nor­ mal times of 05h00 and 20h00 hours, respectively). as a consequence o f the links between temperature, sleep and mental performance, sleep will be d iffi­ cult to achieve and maintain at the new night-time and the fatigue that w ill result w ill give rise to neg­ ative feelings, including irritability and headache. sports medicine september 1997 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mental and physical performance and mood will deteriorate not only because they are talcing place at times too far removed from the circadian peak, but also because the subject is imable to sleep prop­ erly. differences between flights accepting this desynchrony between body time and local time as the main cause o f the problems, and knowing some o f the properties of the body’s timing system, we can understand why jet-lag is worse after an eastward flight. adjustment to a westward flight requires individ­ uals to go to bed and wake up later, and their body clock to delay; by contrast, adjustment to an east­ ward flight requires going to bed and rising earlier, and advancing the body clock. going to bed earlier than is habitual is not likely to be conducive to get­ ting a good sleep. circulating adrenaline levels and body temperature are too high and the individual lias not been awake long enough to become tired. the resulting poor sleep is inadequate prepara­ tion for the next full day and the problem is made worse by the fact that by the time the body is ready to sleep the new local time indicates that is time to get up for the next day! by contrast, after a west­ ward flight the increase in time spent awake before the new bedtime will tend to promote sleep and to offset the fact that it is being attempted when the body temperature and plasma adrenaline levels are rising. more sleep is obtained after a westward than an eastward flight, therefore, even though it still tends to finish too soon. in addition, the body clock can delay more easily than advance, probably because it tends to run slow unless adjusted each day (see above). as a result, eastward flights, which require the clock to advance, are associated with a longer resynchro­ nization time than the ones to the west but crossing the same number o f time zones. also, after a flight to the antipodes, where the time shift approaches 12 hours, adjustment is almost invariably by delay o f the body clock. advice from the above, it must be clear that a full training schedule and peak athletic performance require adjustment to the new time zone. in addition, the problems can be reduced by suitable planning before the flight and actions during it. before the flight i f it is possible to do so, flights should be sched­ uled so that athletes arrive well in advance o f com­ petition. one day for each time zone crossed does leave a margin o f safety, even for competitors trav­ elling eastward. attempts to find the most convenient travel schedules are encouraged. consider departure from regional airports if appropriate and also alternative carriers. an individual’s routines prior to depar­ ture, on the plane and after arrival can be planned once the itinerary is established. in consequence the trial and error element in coping with jet-lag will be reduced. in the week prior to departure it may be possible to adjust the time o f rising and going to bed, the adjustment depending on the direction o f flight. a change o f more than 2 hours is unlikely to be pro­ ductive since this would interfere with the pattern of social and domestic engagements during the day and clashes with time cues from the environment, for example light. the advantage o f this solution is that it enables the traveller not only to retain some semblance of normality dining the days just before the journey but also enables the focusing o f thoughts on the process o f adjustment to the new time zone. in con­ nection with this, altering training times for a few days prior to travel to take into consideration the time o f competition in another time zone is known to be beneficial.'’ during the flight once flight times are known, a routine on the plane may be planned. in daytime flights it will be neces­ sary to stay awake, keep mentally active and per­ haps watch the in-flight movie. on long-haul flights that entail travelling during the night it will be nec­ essary to get some sleep on the plane. the timing of this may be decided in advance and some meals on board can be missed. transit or transfer episodes en route should also be taken into consideration. it is advisable to set one’s watch to local time at the next point o f landing, once on board the plane; in a single-haul flight this would be the local time o f the country o f destination. this helps the traveller to ‘ tune into’ the new local time straighl-away and to adjust behaviour accordingly. in order to compensate for the dry air on board flight, copious rehvdration is advised. fruit juices are best; fizzy drinks should be avoided. alcohol should not be taken, since it acts as a diuretic caus­ ing loss o f fluid. caffeine (in coffee) also stimulates water loss and its arousal effect on the central ner­ vous system means it should not be taken i f sleep is desired. one suggestion has been that the last meal prior to the time allotted for sleep should be high in carbohydrates and low in protein in order to induce drowsiness (this is because carbohydrates provide the substrate for serotonin, a neurotrans­ mitter which regulates sleep). this same line o f reasoning indicates that caffeine and a low-earbo hydrate high-protein breakfast would help raise the level o f arousal and prevent a relapse into sleep. athletes may feel s tiff or cramped because of their restrained posture on board flight. they can perform static exercises for arms, trunk or legs whilst in their seats. also, they can walk down the aisle of the plane frequently and do flexibility or stretching exercises occasionally at the back o f (he plane. this will also serve to remind the athletes that the primary purpose o f the trip is for sport and not tourism. british sports teams travelling to australia have used sleeping pills to induce sleep whilst on board. although drugs, such as benzodiazepines, are effec­ tive in getting people to sleep, they do not guaran­ tee a prolonged period asleep. besides, they have not been satisfactorily tested for subsequent resid­ ual effects on motor performances such as sports skills. studies on british olympic athletes travel­ ling to training camps in florida (a 5-hour time zone transition) have failed to show any beneficial effects o f benzodiazepines on jet-lag.1 a prolonged nap at the time the individual feels drowsy (presumably at the time that he or she would have been asleep in the time zone departed from) is to be avoided it simply anchors the rhythms at their former phases and so resists the 6 sports medicine september 199j r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ' m u z a m m" g "kmn a<!a'ni' poin md ^ e n i e n t non-slicky, non-greasy formulation û ith no residue. lng sensation on skin, with a pleasant menthol aroma.1 boots h e a l t h c a r e 40 electron avenue, isando 1600 ■n .he 0, flu.fa,p,o,fn murt>lpr0,gn u1.) transact t n i m e got acute pain and inflammation covered. flurbiprofen 40 tng r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) adjustment to the new time zone.10 immediately after the flight in the days immediately after a flight across sever­ al time zones, when the body clock is not adjusted to the new local time, there will be a window o f time during the day when the period o f high arousal associated with the time zone just left overlaps with the arousal high point at the new local time. this window may be predicted in advance and should be utilized for timing of training practices in the first few days of'arriving. observations on footballers travelling eastward from the u k to oceania (australia, new zealand and papua new guinea) indicate that late-morning training sessions suited players best over the first days, however." since such a time corresponds to night in u k time, this indicates that other factors, such as absence of fatigue, are important also. the comments (above) relating to the use of hyp­ notics and naps will apply also to the first days in the new time zone. other drugs that act as central nervous system stimulants might be useful. thus, caffeine (in coffee) and theophylline (in tea) can increase alertness. promoting adjustment the major concern, however, is to promote adjust­ ment o f the body clock. several methods have been suggested, differing in their feasibility and in the extent to which they might have side-effects that adversely affect athletic performance. the three main suggestions are as follows: the timing and composition of meals it has been argued that high-protein breakfasts pro­ mote alertness and that high-carbohydrate evening meals (vegetables, potatoes, rice, bread, pasta, desserts, etc.) promote sleep.12 the theoretical grounds for this include the effects upon plasma amino acids that such meals would have and, thence, the uptake o f the amino acids into the brain, their incorporation into neurotransmitters, and the release o f the neurotransmitters. high-pro­ tein meals (meat, cheese, eggs, etc.) undoubtedly raise plasma tyrosine, but whether this promotes the release o f catecholamines by the activating sys­ tems o f the brain, and so promote alertness, is less clear. similarly, high-carbohydrate meals promote the concentration o f plasma tryptophan, but whether this stimulates the raphe nucleus and sleep is also uncertain.1’ there is evidence that electroencephalographic waves show some changes in athletes on a carbohydrate-only diet, but effects on the quality o f sleep have not been demonstrated. the method was promoted in the usa under the title ‘president reagan’s anti-jet-lag d iet’ . scientific tests o f the efficacy o f the diet are few and poorly designed. even so, a variant o f this pro­ posal has been marketed. it consists o f two types of pills, one to be taken in the morning and the othei. in the evening. each pill is a mixture o f substances, the morning p ill containing tyrosine and the:. evening one, tryptophan. the accompanying litera^fg j ture does not enable a judgement to be made on the-;i scientific evaluation o f these preparations. besides, tryptophan achieved bad publicity in the early 1990s owing to impurities found in commercially available products and its use is no longer recom­ mended. melatonin capsules in normal circumstances melatonin from the pineal gland is secreted into the blood stream between about 21h00 and 07h00 hours. it can be regarded as a ‘ dark pulse’ or ‘internal time cue’ . several studies have shown that melatonin capsules taken in the evening by local time in the new zone reduce the symptoms of ‘jet-lag’ .14 this is an important finding, but there are some caveats. 1. jet-lag, as defined in these studies, has concen­ trated on subjective symptoms; we do not know if there would also be improvements in mental and physical performance, and in motivation to train hard or even i f there would be further decrements. 2. it is not clear i f melatonin produced its effect by promoting adjustment of the body clock or by some other means (increasing a sense o f wellbe­ ing or the ability to sleep, for example). recent work suggests that melatonin should adjust the body clock, but this requires careful timing of ingestion according to whether you wish to advance or delay the clock.1s thus, melatonin taken in the evening (on body tim e) will advance the body clock and in the morning will delay it. 3. melatonin is only just becoming commercially available (largely in the usa) and the results from many clinical trials are still awaited. in summary, more information is required before melatonin can be recommended. bright light exposure and physical activity bright light (that is, o f an intensity found naturally but not normally indoors) can adjust the body clock. the timing o f exposure is crucially important1017 and is the opposite o f that for melatonin ingestion; thus, bright light in the morning (05h00-llh00 hours) on body time advances the clock and bright light in the evening (21h00-03h00 hours) on body time delays it. as part o f this treatment, there are also times when light should be avoided (those times which produce a shift o f the body clock in a direction oppo­ site to that desired). table 2 gives times when light should be sought or avoided after different time zone transitions; the timing w ill vary as the body clock adjusts. table 2 the use of bright light to adjust the body clock after time zone transitions bad local times good local times for exposure to for exposure to bright light bright light time zones to the west 4 h 0100-0700* 1700-2300t 8 h 2100-0300* 1300-1900f 12 h , 1700-2300* 0900-1500t . time zones to the east 4 h 0100-0700t 0900-1500* 8 h 0500-1100f 1300-1900* 10-12 h treat this as 12-14 hours to the west * will advance the body clock; t w ill delay tlie body clock; note that this is because the body clock adjusts to delays more easily than advances. 8 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) even though ‘bright light’ is o f an intensity nor­ mally not achieved in domestic or interior lighting, light boxes and visors are now available commer­ cially that produce a light source o f sufficient inten­ sity. light visors, in particular, might prove a useful addition to one’s luggage. since outdoor lighting is the obvious choice, it would be natural, therefore, to consider training outdoors that is jogging, a brisk walk, a swim or a game o f tennis, for example when light is required, and to relax indoors when it should be avoided. this raises the question whether physical exercise and inactivity can, in some way, add to the effects o f light and dark, respectively. current evidence is not conclusive. for the first few days in the new time zone, train­ ing sessions should not be all-out efforts. skills requiring fine co-ordination are likely to be impaired and this might lead to accidents or injuries if, for example, games players conducted sessions with the ball too strenuously. where a series o f tournament engagements is scheduled, it is useful to have at least one friendly match during the initial period, that is before the end o f the first week in the overseas country. subject to these caveats, exercise for athletes is recommended also since it helps them psychologically in their prepara­ tions for competition. in practice, therefore, to combine exposure to bright light and exercise, and to combine dim light and relaxation, would seem practicable. however, there is very little evidence to suggest that exercise by itse lf will alter the speed o f adjustment o f the body clock. to a large extent it might be considered that to adjust as fully as possible to the lifestyle and habits in the new time zone would be the best advice. this is not always the case in the first day or so after the flight. consider a westward flight through eight timezones. to delay the clock requires bright light at 21h00-03h00 hours body time and its avoidance at 05h00-llh00 hours. by new local time, this becomes equal to 13h00-19h00 hours for bright light and 21h00-03h00 hours for dim light (see table 2). it can be seen that natural daylight and night would provide this. consider, by contrast, a flight to the east through eight time zones. now light is required 05h00llhoo hours body time (13h00-19h00 hours local tim e) and should be avoided 21h00-03h00 hours body time (05h00 llhoo hours local time). that is, morning light for the first day or so would be unhelpful and tend to make the clock adjust in the wrong direction (though afternoon and evening light are fine). the timing o f exposure to bright light is critical on the first days after the flight. after a couple o f days, when partial adjustment has occurred, it is then advised to adjust the timing o f the light exposure towards that o f the local inhabitants, so that the visitors’ habits become fully synchronized with those o f the locals. conclusion by preparing for time-zone transitions and the dis­ turbances they impose on the body’s rhythms, the severity o f jet-lag symptoms can be reduced. there has been little success in attempting to predict good and poor adapters to long-haul flights. athletes are generally better than non-athletes in coping with jet-lag and they tend not to suffer as much. the fact that an individual escapes lightly from symptoms on one occasion is no guarantee that he or she will do so again on the next visit. the disturbances in men­ tal performance and cognitive functions have conse­ quences not only for sports performers but also for management and medical staff travelling with the team, who by no means have immunity against jet lag symptoms. an awareness o f the dynamic biolog­ ical adjustments that the body is making means that the adverse effects and discomfort associated with jet-lag can be countered to some degree. it is important to allow time for the slow adjustment o f the body clock, and to be patient whilst this process is taking place. until it has, performance will be poorer and will seem harder to achieve. adherence to the advice above will minimize these frustra­ tions. references 1. r e illy t, a tk in s o n g, waterhouse j. b io lo g ica l rhythms and exercise. o xford: o xford university press. 1997. 2. m inors ds. waterhouse jm . c ircadian rhythms and the human. b ris to l: j oh n wright. 1981. 3. a tk in s o n g, r e illy t. c ircadian va ria tion sports performance. sports med 1996; s i : 292-304. 4. o c onnor p j , m organ ik a th le tic perform ance follow in g rapid traversal o f m u ltip le time-zones. sports m ed 1990: 10: 20-30. 5. r eilly t. h u m a n circadian rhythms and exercise. c rit rev biom ed e n g 1990; 18: 165-180. 6. shephard r . sleep, biorhythm s and human performance. sports med 1994; 1: 11-37. 7. k a rm a m. l a itin en j, p a rtin en m, savanto s. the effect o f fo u r day round trip flig h ts over 10 tim e zones on the circa d ia n varia­ tio n o f salivary m elatonin and co rtiso l in a ir-tim e flig h t a tte n ­ dants. e rg on om ics 1994; 37: 1479-1489. 8. wegmann 11. k le in k . j e t-la g and aircrew scheduling. in : folkard s, m onk t. eds. hours o f work. chichester: joh n wiley 1985: 263-276. 9. jehue r , street d , h uizenga r. effect o f tim e zone and gam e tim e changes in team perform ance: n a tio n a l f oo tb a ll league. med sci sports exerc 1993; 25: 127-131. 10. m inors ds. waterhouse jm . a n ch o r sleep as a synchroniser o f abnorm al routines. in te rn a tio n a l j o u rn a l o f c hronobiology 1981, 7: 165-188. 11. r e illy t, m e llor s. j e t-la g in student rugby league players f o l­ lowing a non-m axim al tim e-zone shift. in : r e illy t. lees a, d avid s k , m urphy w, eds. science and football. london: e & f n spon. 1988, 249-256. 12. graeber r . sing 11. cuthbert b. the im pact o f transm eridian flig h t on deploying soldiers. in : johnson l, tepas d , colquhoun p. eds. b iolo g ica l rhythms, sleep and shift work. lancaster: m t p press 1981; 513-537. 13. leathw ood p. circadian rhythms o f plasm a am ino acids, brain neurotransm itters and behaviour. in : a re n d t j. m inors d, waterhouse j. eds. b io log ica l rhythms in clin ica l practice. b ris to l: j oh n w right 1989; 136-159. 14. a re n d t j, a ld house m, e n glish j, m arks v, f o lk a rd s. some effects o f je t-la g and th eir a lle via tio n by m elatonin. ergonom ics ■ 1987; 30: 1379-1393. 15. lewy a , a h m e d s, jackson j. la th am r. sack r . m elatonin shifts human circa d ia n rhythms according to a phase response curve. c hronobiol in t 1992; 9: 380-392. 16. czeisler c, k rona u er r , a lla n j. b rig h t lig h t in d u ction o f strong (ty p e 0 ) resetting o f the human circadian peacemaker. science 1989: 244: 1328-1333. 17. m inors d, waterhouse j, w irz-justice a . a human phase response curve to light. n eurosci l e tt 1991; 133: 36-40. □ r eprinted with perm ission, sports exercise and in ju ry (1 1 9 7 ) 3, sports medicine september 1997 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) travelling with teams w diesel introduction the purpose of this article is to highlight some impor­ tant and practical hints on ‘qualities’ of the individual physiotherapist, appropriate equipment, daily rou­ tines, and remuneration. the views expressed in this article arc entirely my own and do not necessarily reflect the views of either my colleagues or profession­ al bodies to which i belong. the ‘ideal’ physiotherapist not everybody is suited to travelling with sports teams. certain physiotherapists may prefer the relative ‘com­ fort’ of their practices were everything is at thendis­ posal and help is close at hand. other physiothera­ pists, myself included, enjoy the challenge of travelling and having to make spontaneous decisions. one thing, however, is certain that the glamour associated with travelling with a national sports team is short-lived. this type of work is certainly not for the feint-hearted or oversensitive. recall the press coverage the medical team received in atlanta, if you need any convincing. it has been said, and written, that the best a medical team can hope for is not to get mentioned during a tour! physiotherapy, like any other medical profession, has its specialities. the treatment of sports injuries is constantly evolving and physiotherapists need to con­ stantly keep up to date with new trends. it is about time that physiotherapists ‘specialised’ in the treat­ ment of sports injuries were recognised as such. perhaps a nationally accepted accreditation pro­ gramme is the solution. i will cover this area at the end of the article. having now travelled with several different sports code, i have come to the conclusion that there are cer­ tain physiotherapeutic techniques or skills which are essential. perhaps one of the most important skills is massage. irrespective of what team i have travelled with, the majority o f my ’treatment’ time is spent mas­ saging. massaging may be requested by the sport per­ son for general relaxation; pre-event stimulation; post event muscular stiffness; and even during an event. if done correctly certain massage teclmiques can also be used to effectively treat some chronic soft tissue injuries i.e. deep transverse friction’s, deep longitudi­ nal massage, myofascial release and trigger points. the way in which a pre-event [stimulatory! massage is given varies between sports. apart from focusing on different muscle groups, the medium through which the individual is massaged may also change. on the one extreme i have used ‘foul-smelling’ oil (arnica, tiger balm, nutmeg) on hockey players who swear by its ‘magic’, whereas many swimmers simply will not allow you to use any oil or powder whatsoever. swimmers prefer to be massaged over loose fitting clothing. the reason for this, according to the swimmers, is so that their ability to ’feel’ the water is not affected after hav­ ing ‘shaved’. manual therapy, involving maitland techniques which includes joint manipulation, rales as a close sec­ ond to massage as far as taking up treatment time goes. manipulative therapy, assuming it is done at the appropriate time and for the right reason, can and does lead to remarkable reduction in symptoms. a third vital skill necessary is stretching. knowing when, and how, to use the various stretching techniques, such as pnf; neural; static; and dynamic, is important. travelling with multi-code sports teams e.g. olympics, challenges the physiotherapists knowledge o f stretch­ ing since each code requires a unique series of stretch­ es. just as training is sports-specific so is stretching. electrotherapy, despite its proven effects in treat­ ment of soft tissue injuries such as those commonly encountered in sport, does not feature as prominently as ‘hands-on’ techniques. this is mainly because it. is simply not practical to travel with much more than a simple combination (ultrasound and interferential) unit. acupuncture, 0 1 1 the other hand is rapidly becom­ ing more and more popular in the treatment of spoils injuries. this, i am sure will feature prominently in future tours because of its obvious case of transport and popularity amongst sports persons. part and parcel of travelling with sports teams is allowing injured athletes to continue to participate. clearly the extent of the injury will determine whether or not an injured athlete may or may not participate. however, the decision is not always an easy one. hence, the athlete and physiotherapist may have to rely quite heavily on strapping to see them through the next match or event. as in the case of stretching, each sports codc has its preferences when it comes to strap­ ping. a gynmast’s ankle cannot be strapped the same way as you would strap a rugby player’s ankle. the gymnast needs to be able to point her toes and walk on a narrow beam thus heavy strapping would obviously be inappropriate. extended tours, anything longer than 0 1 1 c week, will at some stage require the physiotherapist to imple­ ment rehabilitation programmes for the injured ath­ letes. almost without exception the physiotherapist ‘inherits’ a wide range of chronic low level injuries. this means that even before the tour has started some of the athletes will have an injury of soils. in these instances the physiotherapist must continue with an existing programme or even be required to initiate one. thus a sound knowledge o f strength training and phys­ ical rehabilitation principles will also be o f great bene­ fit to the physiotherapist. in cases where the tour may last several weeks even non-injured athletes will derive benefit from strength training. often this is done in conjunction with the coach or fitness trainer. the physiotherapist should also be able to treat minor medical problems such as abrasions, blisters etc. as well as the more major problems such as frac­ tures, dislocations, and spinal injuries. tliis knowledge is perhaps more important for physiotherapists who 10 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a very one fe e ls pain at some time . r o b e f t . i o o • s i g n i f i c a n t a n a l g e s i c , a n t i i n f l a m m a t o r y a n d a n t i p y r e t i c a c t i o n . • r a p i d t h e r a p e u t i c r e s p o n s e e n s u r e d ' . • a v a i l a b l e in a c t i o n p a c k 1 5 ’s a n d s u p p o s i t o r i e s 12 ’s. 3 flurbiprofen loomg « x . ♦ rabbi* i(k) mp. <u|)po«iu»rics kh) mg. basf pharma r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) travel with the less ‘professional’ teams since the med­ ical support is often limited to a physiotherapist only. apart from these above mentioned skills the phys­ iotherapist may also be approached for advice on other medically-related topics. international travel brings several problems to the fore, such as acclimatisation and strange eating habits. advice on how best to accli ̂ matise, to time changes, humidity and temperature changes as well as what food stuffs to avoid and when to eat may also be requested from time to time. young inexperienced athletes who may not have travelled abroad or been away from home for such long periods struggle to remain focused throughout the tour. because of the close personal relationship and trust that often develops between athlete and physio­ therapist, we are often the first to pick up such prob­ lems. providing the necessary psychological support may end up as the responsibilityof the physiothera­ pist. again, the ideal situation would be to have a sports psychologist present. however, unfortunately this is all too seldom the case. warm-ups and cool downs may be taken by either the coach, fitness trainer, captain or as in the case of the national men’s hockey team the physiotherapist. thus, without trying to promote, physiotherapy too much at the expense of other professions, a physio­ therapist travelling with a sports team may have to take on the roles of masseur, chiropractor, first-aider, fitness trainer, exercise physiologist, nutritionist, psjr chologist, and even manager!!. in the ideal situation sports teams should travel with a specialist from each field, however whenever this is not possible the phys­ iotherapist is likely to be called upon to perform the necessary functions. several characteristics or personality traits which may facilitate the working relationship between the physio, the sports person, and the rest of the manage­ ment include: flexibility this refers to the physiotherapist’s flexibility in terms of treatment approach. anybody who has worked on athletes, soon comes to realise that athletes are very aware of the latest treatment techniques and also what works best for them. by acknowledging that there are many different ways to sort out an injury the physio­ therapist is well advised to, at least initially, use the treatment the athlete is most comfortable with. the quickest way to lose credibility with a sports person is to ‘force’ them to accept another form of treatment and then for things to go wrong, even if their drop in per­ formance, or recurrence of symptoms, has nothing to do with your treatment. once you have gained the con­ fidence o f the individual you may consider changing treatment. perhaps the physiotherapist may even learn something new in the process! another area which requires a degree of flexibility is the working environment. single hotel rooms, or sharing a room with the doctor, or even another sports person, often leads to working under very cramped conditions. the ‘hours’ which you work are also extremely flexible and need to be worked around the teams schedules. physically fit the physically demanding nature of the work, as well as the visual impressions made by the sports person of the physiotherapist, mean that by being physically fit the physiotherapist is able to cope with the work load and enhance their credibility. to the sports person it indicates that you -have some understanding of the demands and requirements of their sport. i f you are called upon to devise a ‘fitness’ test it is imperative that you understand the particular physical require­ ments of the sport as well as the individual’s role with­ in the sport. by being physically fit you are more like­ ly to appreciate these needs. equipment carting heavy, and often very bulky, equipment hall­ way around the world is not my idea of fan. thus the physiotherapist must consider very carefully and decide between what is ‘essential’ and what would be nice to have. the most important single piece of equip­ ment is a plinth. it must be portable, reasonably solid (a compromise needs to be made between weight and strength of the plinth), have a breathing hole, and have a strong protective cover. treating on a hotel bed not only compromises the effectiveness of your treat­ ment but also spells disaster for your back, the approximate weight of a plinth is 18 kg’s (your baggage limit is only about 20 kg’s!). the next essential piece of physio equipment is a portable combination umt. this s h o u ld ideally be bat­ tery operated and fit into a small bag or case. the two modalities which must be available are ultrasound and interferential. be aware of the power supply of the country you are visiting as this w ill determine whether or not you require to take a transformer along with you. international plugs are also different so make sure you take the right adapters with you. the average weight of such units, including bag and accessories, may be 8 10 kg’s (your total weight is now in the region of 30 kg’s and you have not started packing your bag yet). there are several essential consumables which must be included in you r kit. these are massage oil, strapping, rubber tubing for strength training, acupuncture needles, and a rudimentary first-aid kit. just how rudimentary your first-aid kit is will depend upon the presence of a doctor on the team as well as the country you will be visiting. the weight of these essential consumables can vary' from as little as 5 kg’s up to 15 kg’s. there is another ‘essential’ piece of equipment that i will not travel without, my laptop computer. the ben­ efits, certainly in my case, definitely outweigh (excuse the pun) the disadvantages. by being able to enter my treatments on a daily basis i am now able to produce a complete medical report at the end o f the tour. the amount of time and effort i save by not having to do a report when i return home is immeasurable. having a modem and e-mail means i can communicate with my family and practice on a regular basis and a lot more cheaply. hopefully all touring teams will travel with a laptop which can be programmed to capture data to benefit future teams and provide an ongoing medical file for oiir sports persons. it is not uncommon for me to arrive at the airport with baggage which weighs in the region of 40 to 50 kg’s! maybe this is the most important reason of all as to why you should be physically fit. daily routine each team or group of athletes will have their own times when they will train and when they compete. 12 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the temperature of the country may influence the time of day when the athletes can exercise. working out treatment times is much harder for individual sports; such as swimming compared to team sports such as hockey. for individual sports you sit with a problem of having some athletes competing and others not. the difficult}7 is in not being able to be at the event for the competitors and at the hotel for those not competing at the same time. generally speaking, you can be assured that you will be working most o f the day and often well into the night. the reason is simply because when the athlete is competing you need to be present and when the athlete is ‘resting’ you are treating them. teams from countries like australia and holland are fully aware of these demands, and for this reason often trav­ el with more than one physiotherapist plus a masseur. returning from trips such as the olympics, 6 weeks away from home, often leaves the physiotherapists drained of energy. being away from you r practice for that period of tune means yon cannot afford to take any more time off. perhaps if we received adequate remu­ neration things would be different. however, let me assure you that this is not the case. this brings us to my next topic. remuneration this is a thorny issue which i feel needs some urgent attention. the effort, responsibility, as well as direct and indirect income lost through being away on tour deserves appropriate compensation. one problem is the lack o f an appropriate fee structure. the current, physiotherapy (private practitioners association) guidelines recommend somewhere in the region of r 2000.00 per day. to the best of my knowledge not even physiotherapists who travel with our ‘professional’ sports teams receive this amount. certainly, physio­ therapists travelling with ‘minor’ sports codes are lucky to receive anything at all. another problem is that physiotherapists, myself included, have literally jumped at the opportunity to be linked to a national team. with the dramatic increase in sports tours it is becoming increasingly difficult to be awav from your practice for a huge portion of the year and also finding suitably qualified physiotherapists to travel. this leads to a high turnover of physiotherapists working for a specific code, which in turn effects the continuity of treatment. this may be another motivating factor for the implementation o f an accreditation process to help formulate policy decisions. implications to your practice the decision to travel with sports teams also has direct implications for your practice. these include :a) employing sufficiently well qualified physiothera­ pists to run things in your absence b) disruptions in the treatment of some of your clientele. this can be particularly distressing to a competitive athlete whom you are treating c) cost and risk of employing a locum d) loss of income you ordinarily would have generated e) no remuneration for time lost organising equip­ ment, etc, before the tour despite these draw backs i believe my ‘travelling with teams’ has enriched me both as an individual and physiotherapist. the people you meet and the places you visit make it all seem worthwhile. i t is also a very' effective waj7 in which we can promote ourselves and tlie wonderful profession o f physiotherapy. □ letters to the editor r e a d e r s ’ le t t e r s c o n ce rn in g a r tic le s in the jo u r n a l a re in v ite d , fo r c o n s id e r a tio n fo r p u b lic a tio n . p le a s e p o s t to : t h e e d ito r, s .a . j o u rn a l o f s p o rts m e d ic in e , p o b o x 115, n ew la n d s, 7725. spo rts m e d ic in e septem ber 1997 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the sa cricket team the physiotherapist’s viewpoint c smith, physiotherapist, s a cricket team introduction since south africa’s re-introduction into the world sporting arena in 1991, we have seen most of our sport­ ing teams compete on the international stage. this has incorporated 2 cricket world cups, 2 olympic games, the hockey world cup, winning the 1995 rugby world cup and 1996 african nations cup o f football, to men­ tion but a few. not only have these achievements had a positive and rewarding effect on our sportsmen and women and the people of our country who support them, but also the so-called “backroom team” of the sports medicine fraternity (doctors, physiotherapists, masseurs, nutri­ tionists and exercise specialists) who have becomc an integral part of keeping our teams fit and healthy and striving for their winning ways. befoi'e 1991, the “back­ room team” had very little experience in managing international sportsmen and women, let alone touring the w’orld with our sports teams, simply because of our nation’s inactivity in international competition. however, this has now all changed and hardly a week goes by without a rugby, football, cricket or ath­ letic event occurring where our teams and individuals challenge for the highest honours. thus there are now those physios and doctors who find themselves in the enviable position of being able to share their experi­ ence and knowledge of working in this type of environ­ ment over the last 5 or 6 years. this article will hope­ fully do just that; shed some light on the workings of the physiotherapist with the south african cricket team over the past 6 years. touring preparations being involved with a sports team such as the sa cricket team, which now' travels around the country and the world for about 8 to 10 months of the year, brings about a whole new work environment for the physiotherapist. the comforts of a private practice are very few. each new' hotel room doubles as the travel­ ling surgery, and gets set-up with a portable massage bed, electrotherapy equipment and a cricket coffin full of strappings,braces, medications, cryotherapy, protec­ tive and rehabilitation equipment and other odds and ends which may be required. it is important if you are going to be touring for longer than 6 weeks to take along extra consumables and items which you may not be able to get in the country you are touring. these include ultrasound gel, anti-inflammatory gel (w'hich i used coupled together with the u/s gel), massage oils, sunscreen creams, specific strappings and dressings, joint guards and braces, insect repellant, superglue, international plug adapters, a neck collar, shock absorbing materials (sor bothanc or poron), extra acupuncture needles and alco­ hol swabs, cliniband and tubigrip, finger splints, scis­ sors and scalpal blades, coolant “ magic” spray, batter­ ies or batter}' charger, heel raises and arch supports, pencil torch, and an alarm clock (so you don’t miss the bus and get heavily fined). the medical bag, which is normally handled by the doctor when accompanjing a tour but w'hich may have to be stocked and carried by the physiotherapist if no doctor is present, should contain the following essen­ tial medicines. .analgesics (paracetamol), nsaids, antibiotics (should a doctor w'ant to prescribe a course), antacids, antidiarrhoeals, throat lozenges, antihistamines (the non-drow'sv type), eye and ear drops, topical creams (antifungal, antibiotic, corticos­ teroid, anti-inflammatory, antihistamine), vitamin b 12 injeetibles,supplements (magnesium, calcium), cough syrup and swabs. dressings such as flcxipore to treat grass bums shoidd also be included. work environment once on tour, the room service staff in die hotels get to know' very quickly w'hich room is the treatment room with the endless requests for ice. (iradually, the play­ ers stream in and out of the travelling surgery until we check out and move onto the next hotel, w'here the same procedure begins. the type of work on tour is not strictly confined to pure physiotherapy treatment. one has to be flexible and prepared to help out in numerous other ways, so as to blend in with the activities of the team. for exam­ ple. wc can be busy up to 7 days a week with practice and match days and thus it is almost expected of the physiotherapist to get involved and assist wherever possible. for example, throwing to the batters in the nets, catching the return throw's from the fielders for the coach during fielding drills (this may lead to a major baseball catcher contract), acting as “wicket­ keeper” to the bowlers when the)' practice bowling on the middle strip, and generally helping out wherever possible. this aside the physiotherapist then normally retreats to lire hotel with the team where the real physiol herapy work starts. in these instances, there may not be many acute injuries to care for, and thus most of the work done is of a maintenance nature, for example mobilising chronic stiff backs, massages, rehab maintenance and then visiting cricket’s equiva­ lent. of the 19th hole, the hotel team room for a chat and a sample of the local beverage. when travelling around the world, one has to rely heavily on facilities of the host country. work condi­ tions and medical facilities vary greatly around the world amongst the cricket playing countries. many of the stadia on the asian sub-continent do not have an adequate medical facility. the medical/physiotherapy room is often converted from the cleaner's old storage room next to the dressing room and the massage couch looks more akin to the stadium manager’s derelict bed which he’s just replaced. thus, there are times w'hen the physiotherapist has to set up shop inside the dressing room, placing the plinth in the smallest place of available space and w'orking in and amongst the players. there has even been an occasion in pakistan 14 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) c e l e s t o n e putti ng c o r t i c o s t e r o i d p o w e r r e s p o n s i b l y in y o u r h a n d s c e le s to n e d e liv e rs a n t iin f la m m a t o r y and i m m u n o s u p p r e s s a n t e f f i c a c y to tr e a t a wide spectrum of corticosteroid-responsive c o n d ition s . c e le s t o n e s o lu s p a n is the o n ly tool you n e e d to s a f e l y p r o v i d e t h e t h e r a p e u t i c benefits of a solution and a su sp en s io n in on e in je c t i o n . fo r r a p id a b s o r p t io n and s u s t a i n e d a c t i v i t y in m u s c u l o s k e l e t a l , re spiratory and derm atolo gical conditions. rapid and sustained localised control of inflammation flc re ix l a aivltion ai schering-plough ipiyj ud(applktmll m electron avenue isando woo usa co reg t o 0s1k x 7iq? r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) when the dressing room was so small for the 15 play­ ers that we placed the treatment table on the patio out­ side the dressing room and i did my work in full view of the crowd outside. some o f the grounds do not pos­ sess a massage table and you may have to transport the portable massage couch from the hotel to the ground each day and then back to the hotel for any treatment work to be done in the evenings. however, this is not the case everywhere through india and pakistan. in calcutta at the famous eden gardens, a ground with a crowd capacity in excess of 100 000 people, the facilities have been upgraded con­ siderably. there is a separate and quite modem med­ ical room inside the dressing room and even a small x ray suite upstairs in the pavilion with a radiographer on stand bj7 if required. when south africa played their first test match there at the end of 1996, we utilised these facilities three times for 3 separate hand and fin­ ger injuries. the work load o f the physiotherapist varies from time to time during a tour. there may be days where you’re treating 75% of the players and at other times as few as 10%. most of the work is done either before or after the game or during the batting innings, as you don’t get the opportunity to work on the players while they7 are fielding. a typical scenario for the physiotherapist on a match day would be to have breakfast and leave for the ground at least 2 hours before start of play. the team would start their warm-up drills about 90 minutes before play starts and include a few team games and running to increase the body temperature, stretches, fielding exercises, and then practising specific skills such as catching, throwing, bowling and batting. any strapping or wound dressing is thus done before the warm-up commences. the preparation for a day-night game is slightly dif­ ferent. the mornings are often spent treating the play­ ers and preparing them for the game (massage, mobil­ isation, strapping) before we head off to the ground around midday for lunch. thereafter, the programme for the warm-up and pre-match preparation is much the same as for a clay game. special considerations the sporting or competitive edge is an analogy which is used to describe various methods of preparation or training which separates a winning team from the minor placers. in the sa cricket camp, that exact mind set exists; among the players, managerial staff and the administrators. the team makes use of “ specialists” in each field to hone and train the skills and habits which may help the cricketers achieve the edge over their competitors. we use a dietician to advise on meal preparation and to educate the players regarding the kinds of food­ stuffs which are best suited to providing sufficient energy to play the game effectively. we have a full-time trainer/biokineticist who supervises the players' train ing programmes and who takes the physical training sessions wit 1 i the team. a podiatrist looks after the players footwear and also provides specialised orthotics where these maybe needed. the players’ fit­ ness levels are evaluated twice a year and neurophysi ological as well as optical testing procedures are also performed. air travel on long tours can be problematic. when crossing time zones, w'atches are placed onto the future time as soon as we board the plane. the players are discouraged from drinking alcohol on board because of the effects of dehydration. after a long flight or a day’s travel with flight connections, we try fit in a loosening session in the afternoon to stretch the hamstrings and iliopsoas muscles which become shortened during long periods of sitting on an aero­ plane. types o f injuries the majority of injuries we experience with the sa cricket team are either of an acute traumatic (76%) or chronic overuse (24%) nature. the common acute bowl­ ing injuries which occur include ankle sprains, side strains (a strained abdominal muscle at the point of insertion onto the 12th rib), hamstring muscle strains and more rarely the spinal stress fracture, which tends to come on slowly but can occur as an acute traumatic injury. chronic bowling injuries manifest more in the form of a posterior talar impingement syndrome, patel­ la tendinitis, symptoms pertaining to meniscal wear and tear or lower backache o f a discal nature. batting injuries mostly occur as a result of being hit by the ball causing severe bruising or a haematoma. the areas often involved are the thigh, arm, hand, foot or chest regions. batsmen regularly get hit on the hand and fingers which either bruise the interphalangeal joints or fracture the metacarpals or phalanges. simple transverse or chip fractures recover within 3 to 4 weeks but intra-articular joint fractures may need to be surgi­ cally repaired. also be aware of an avulsion fracture of the extensor pollicis tendon attachment to the base of the distal phalanx of the bottom-hand thumb which occurs when the ball strikes the thumb and forces the d ip joint into hyper-flexion. a blow to the foot or toe can fracture the tarsal or metatarsal bones but commonly, bleeding underneath the toe-nail is all that occurs. this is best managed with immediate draining by drilling a few holes through the toe-nail to release the blood underneath. injuries to the face and head are also common amongst batsmen, even though they generally wear protective head ware. a glancing blow7 off the helmet doesn’t cause much damage. however, there have been 3 separate head injuries which occurred in different ways even though the players were wearing helmets. one player fractured his medial orbit when the ball struck the player on the eye due to the gap between the helmet and the grill being large enough for the ball to penetrate. a second facial injury occurred when the ball struck the grill and pushed it back onto the bats­ man’s cheek fracturing his zygomatic arch. thirdly, another player was struck straight onto the helmet, which caused severe concussion. the helmet cracked from the blow7 of the ball, thus doing its job and was therefore replaced. acute fielding injuries take the form of shoulder sprains (landing on the shoulder while diving for the ball), hamstring tears and bruised hands (palmar sur­ face) or dislocated fingers. traumatic injuries aside, fielding injuries generally occur as a result of the field­ er being inactive for a period of time when the ball does not come to them and then having to sprint off to field the ball once they have become “ cold” . we try to combat this by7 educating our players to keep active and loose in the field with regular stretching and loos16 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) erring exercises. the common chronic fielding injuries involve shoulder pain with throwing due to rotator cuff or long head of biceps tendon strain or minor anterior instability of the shoulder. on analysing the general injury statistics associated with the sa cricket team, some interesting facts emerge. the area of the body most frequently injured is the thigh (21%), followed by the knee (13%) and then the thoraco-lumbar spine (12%). the calf and shin, cervical spine, the fingers and the ankle seem to receive less trauma, but still do present a risk area for cricket injuries. i f we look at which structures are most at risk of injury, we find the following; the skeletal system (the bone and joints) comprise 31 % of injured structures, followed by the muscles 26% and tendons 18%. the most common injuries receiving treatment are thus bone bruising/fractures and joint sprains, by mus­ cle and tendon strains, soft tissue bruising/ haematomas and then ligament sprains or tears. when analysing injury types, acute injuries appear to be more common than chronic injuries and extrinsic factors seem to lead to more injuries than intrinsic fac­ tors. injuries are more likely to occur during matches than practices. however, adding those injuries which occur during practices with chronic recurring or long­ term ailments appear to equal the number o f injuries which occur during matches. there does not seem to be a significantly greater number of all general injuries caused by batting, bowl­ ing or fielding. however, if vve analyse the number of serious injures which may have ruled some players out of a single or multiple number o f games or an entire tour, then it appears that bowling would be the most injurious type of play and lead to the most wear and tear or attrition among international cricketers. out of 62 major injuries, bowling caused 33 of these injuries (53%), followed by 19 as a result of batting (31%) and 15 fielding injuries (24%). the bowling injuries seem to be confined to the lower limbs or lumbar spine whereas the batting injuries to the hands and fingers and fielding a combination of leg muscle strains and hand or finger fractures. nearly three times as many cricket injuries occur as a result of and during the 1-day internationals than compared with the 5-day test match. furthermore, for every one 1-day match day, at least 3 injuries occur whereas the number of injuries occurring during the 5 day game seem to be equal to the number o f playing days. this merely indicates the greater intensity and the increased risk of injury of the one-day game com­ pared to the 5-day test matches and indicates the need for a rotational system of players, especially the bowlers to reduce their wear and tear and minimise the risk o f injury during the normally congested one day match programmes. i f we look at the length of the tours and compare this to the number of injuries, then we find a trend showing that tours of a longer duration with a greater number of match days are likely to result in a greater number o f injuries. physiotherapy treatment tips on tour o v e r the years i ’ve found in my experience that the fol­ lowing methods of treatment have been effective in the management of the following conditions. acute soft tissue bruises/haematomas treat immedi­ ately with an ice pack (10 minutes) followed by low dosed pulsed ultrasound (5 to 8 minutes) every 2 hours. this helps to get the bruising to dissipate quickly and prevents the formation of a hard contusion with adherence or stiffness in or around the muscle belly. finger bruises treat immediately by immersing the finger into a glass with iced water every 2 hours. twenty four hours later begin hot and cold treatment also every 2 hours to reduce the swelling. grass bums/skin grazes wash immediately after play and then apply either a tegaderm or flexipore dressing with tubigrip to keep it in place. change the dressing when it leaks exudate or if it comes off. never apply mercurochrome to a graze as this only forms a scab over the wound which comes off if the player slides over the ground on the grazed area again. the tega­ derm or flexipore dressing allows the graze to heal from within because of the good oxygen perfusion through the dressing. full recovery normally takes 7 to 10 days. bruising/bleeding under the toe/or linger nail imme­ diately drill 2 to 3 holes into the nail bed in the area of the bleeding to drain the blood and exudate. use either a syringe needle or a paper clip which has been heated up and is pushed through the nail. this must be done every hour to completely drain the fluid and relieve pain from pressure build-up under the nail. apply a betadine dressing over the nail to prevent infection. muscle strains apply ice as soon as possible. remember that rehab must be action specific ie. if it is a bowler with a tom hamstring, then his injury must be rehabbed and strengthened in the final stages with the bowling action whereas a fielder with a tom hamstring from fielding must include the same fielding drills in his final rehab stages. □ spo rts m e d ic in e septem ber 1997 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy in south african soccer d becker and s felsher introduction soccer is the most popular sport in south africa and world-wide. there are approximately 40 million organ­ ised players and between 100-150 million participants in total. as the popularity of football has grown, foot­ ball injuries have become the object of increasing med­ ical attention. south african soccer is now starting to show signs of development. the national team winning the africa cup of nations in january 1996, and recently the national under 20 side reaching the finals of the african youth championships thereby qualifying for the youth world cup in malaysia. there are currently 4 active national teams: bafana bafana, the olympic under 23 team, the under 20 team and the under 17 national team. the latter is selected from an annual u17 youth regional tourna­ ment, as is the u20 national team. the u23 team is selected from the u17/u20 teams as well as from an u19 talent identification programme which takes place annually. bafana bafana is selected from the professional ranks as well as from the junior teams. our involvement with the national teams began in 1994. we are involved on a consultancy basis which means that during national team activity, we are with the team full-time, that is, we camp with the team usu­ ally 1 week prior to a match. when the teams are not active, we then operate out of our private practice in durban. functions as a physiotherapist for home and away games as the physiotherapist, it is very important to be aware of the activities o f die players both around the country as well as abroad. it is imperative that you are informed of, or enquire about injuries sustained prior to a camp as well as having a knowledge of fitness lev­ els of all squad members. the dietary education of the players is vitally important. it is our responsibility prior to the camp to ensure all fluid and food requirements are taken care of. the food types and quantity thereof are worked out in accordance with the fixtures as well as the training schedule for the week. the selection o f these food types needs careful attention as they must include food groups that players are used to and at the same time being nutritional in content and not too high in fat. interestingly enough, we discovered that some junior team members complain o f cramps and diarrhoea when exposed to food groups which are not normally in their daily dietary regime. what we now do is give the players a questionnaire thereby avoiding any problems. they say “ old habits die hard” . well, this cer­ tainly pertains to the attitudes of some players and coaches alike when it comes to the pre-match meals. clive barker, coach of the bafana bafana, will be the first to admit that the favourite “ steak, eggs and chips” recipe still would top his list of old habits had he not been told better by the sports science institute of south africa recently. on arrival, all players who have “minor knocks and bruises” are medically screened. at senior level, play­ ers are weighed and records from camp to camp are monitored. once the musculoskeletal screening has been completed, the day to day routine is as follows: 7.30 8.30 8.30 9.30 10.00 12.00 12.00 1.30 1.45 3.30 4.00 5.30 7.00 8.00 8.30 11.00 breakfast treatment/ massage/strapping training (we are responsible for the warm-up and stretching of the players) lunch treatment/massage training (the senior team usually utilises one of the health & racquet clubs for their 2nd training session of the day). dinner treatment/massage on match day, the pre-match meal is arranged 4 hours prior to the kick-off. before and after the meal, players filter in and out of the physio room looking for “ touch ups” , massages and strapping amongst others. generally, we have learnt from travelling into africa, that prior knowledge of medical services avail­ able at the stadium must be acquired. this will include ambulance services, stretchers, medical evac­ uation and the distance to the nearest trauma outpa­ tient unit. it is not uncommon in some african coun­ tries to find none of the above mentioned amenities available. during the game, we are involved with field injury management and here it is important that one’s prac­ tical knowledge of emergency first aid is of a very high standard. we have learnt not to “ball watch” during a game as off-the-ball tackles and mechanisms of injury might be missed. when the senior team has played in front of 80 000 ecstatic fans, trying to get information out of a player on the field is almost impossible due to the noise levels. once the game is completed we are involved with post-match injury management which will include diagnosis and immediate treatment. communication with club management and medical personnel is important once the player returns to his club. africa cup of nations 1996 winning the africa cup of nations (acon) in january 1996 was certainly the proudest moment for sa foot­ ball. interestingly, there were few injuries in a compe­ tition that was extremely physically demanding. at the time, steve flesher was involved in the acon medical committee in co-ordinating the physiotherapy services 18 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) at all the venues. during the tournament, it became quite a difficult task to keep players and technical teams stimulated through 4 weeks of competition. the health & racquet club provided a good outlet as well as indoor soccer/basketball/volleyball etc. the hotel also provid­ ed pool tables, darts, table tennis as well as board games to keep players occupied at night. it was also our role to educate players in the month preceding the tournament on banned substances. lists were provided to players and they were told to consult the medical team before taking medicines. current status of medical/physiothera­ p y services in sa football the formation of the south african football medical association (safma) a few years ago as the official sports medicine body controlling activities in sa foot­ ball has not proved to be a great practical success. when formed, no physiotherapists or emergency first aid personnel were included. consequently, medical structures that would benefit sa football remain to be developed fully. the current medical/physiotherapy set-up in the professional soccer league (psl) of sa football is almost non-existent. only a few psl clubs have part time physiotherapists and doctors. the rest of the clubs have no medical personnel at all. the set-up in the amateur ranks and junior ranks is even worse. this is of great concern as players at all levels will be affect­ ed by injury at some stage. south african players, coaches and administrators need to be educated on injuries, fitness, nutrition and many other aspects relating to their physical well being. sports science institute of south africa the senior national team and the u20 team have recently been tested at the sports institute. the test­ ing oi these squads has been instrumental in making coaches as well as players aware of the importance of both the mental and physical components needed to be a top class footballer. testing like this should pro­ vide us with valuable data and certainly with the junior teams being tested, help us develop our footballing youth into world champions. the two days at the sports institute was a great learning experience for all concerned. in conclusion, we are both privileged to be part of the national team set-up. working in front of 100 000 ecstatic sa supporters has to be the thrill of a life­ time. let’s hope the next thrill will be in france in the 1998 world cup. □ sports medicine september 1997 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutritional challenges for olympie athletes a review article j johnson (rd)(sa) bsc (uct) grad dip ther diet(uct) introduction south africa has shorn that its recent re-emergence into world sporting events has not gone unnoticed and our athletes are proving to be highly competitive. with exercise science and research playing a major role, our athletes should be assured of the best training and preparation needed to optimise performance. athletes are continually seeking to gain a competitive edge either through scientific or other means, one of which is nutrition. because eating habits take a lifetime to develop, it takes dedication and determination to con­ tinue with the dietary changes necessary to ensure optimal performance. many athletes prefer the tablet form of nutritional advantages rather than having to manipulate daily food choices in order to follow a prop­ er well balanced meal plan. goal setting achieving this well balanced meal plan is not as easy as is seems. elite athletes can no longer follow a stan­ dard high carbohydrate (cho), low fat diet. instead each sport now has specific guidelines and recommen­ dations for nutritional practices that need to be con­ sidered and it is up to the athlete to follow these through. every elite athlete should have his/her own individual nutritional goals that he/she is working towards. this can only be established once an appro­ priate performance body composition goal has been set. body composition when interpreted correctly, is an effective tool for performance appraisal. it is well known that there is a positive correlation between; i) absolute fat free mass and performance in object pro­ jection sports; ii) relative fat free mass and perfor­ mance in body projection sports; and a negative corre­ lation between fat mass and performance in body pro­ jection sports. but there is the mistaken belief that if performance improves with a slight weight loss then there will automatically be more improvement with further weight loss.' this can lead to athletes striving for unrealistic body fat levels particularly when event selection depends on body composition. it should be noted that fatigue, reduction in performance and men­ strual irregularities could all be consequences o f keep­ ing body fat levels too low1 particularly when there is associated loss of muscle mass. the most appropriate and practical method for determining body composition is the use of skinfold measurements. unlike body weight or the body mass index (bmi) (wt/ht2) which do not take changes in the relative contributions of muscle and adipose tissue into account2, skinfold measurements can be used on their own without any predictions of body fat levels being made. according to johnson,'* the sum o f skinfolds should be taken as an absolute measurement and not converted into percentage body fat using various equa­ tions as there are too many inaccuracies and individual variations in non-fat tissue density are not taken into consideration. a key factor for olympic athletes is to be aware of measurements taken by inexperienced per­ sonal particularly if they are being followed longitudi­ nally. human error and differences between individu­ als can occur making interpretation of minor changes in readings inappropriate. it is also important for ath­ letes not to set a particular skinfold sum as a goal but rather to set a ‘range’ which would then be more achievable.4 one method presently being adopted by sports scientists in south africa is the measuring of 7 skinfold sites for females and 8 sites for males and comparing them to the norms for age and sex and is based on the o-scale physique assessment system. further information on sport specific skinfold mea­ surements can be obtained from telford.4 energy balance one of the most difficult challenges facing any elite athlete is getting enough kilojoules in each day. with so many hours of the day taken up in training or other preparation, athletes have to be particular with their food selection and timing. they cannot rely on take away foods, but should plan ahead and arrange their own portable food and drink so as to be able to eat whilst travelling or resting, thereby utilising their time efficiently. in weight class sports, athletes have to be a lot more particular about food choices. they need to establish a balance between meeting the energy demands of training and meeting their correct body weight and body composition goals. very often too lit­ tle energy is consumed which results in fatigue, lethar­ gy and reduced performance during training and com­ petition. establishing the optimum amount of energy needed for an individual is not easy. requirements vary' from day to day depending on overall training and intensity, therefore precise figures are impossible. predictions can be made using tables and equations based on rest­ ing metabolic rate, growth and amount of work done. the schofield equation6, see table 1, when used in combination with estimates of energy costs of activities (kilojoules/minute) is sufficiently accurate for everyday use/ there are also numerous computer packages available that estimate the energy needs of athletes using similar techniques. close monitoring of body composition and body weight wall determine whether energy balance is being achieved. the right combination gaining that winning edge also depends on ensuring the correct nutrient proportions of the total energy7 intake. the nh&mrc (national health and medical research council) recommendations that a healthy diet consists of 50-60% carbohydrate, 15-20% protein and 30% fat cannot be used in all high performance sports. there are now numerous studies available illus­ trating the importance of a high cho diet in muscle glycogen metabolism in endurance sports.”'10 recent 20 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) evidence suggests that the high strength, explosive sports also require glycogen as the primary energy source. but it is not appropriate for all athletes to simply strive for a diet containing 60% cho. it is more impor­ tant to ascertain the absolute amount of cho intake in grams per day. this is best illustrated by the following example. a light-weight runner of 42kg may be taking a diet containing 60% cho which is only 225g cho, insufficient to replenish glycogen stores. costill recom­ mends 7 logcho/kg/d, depending on the intensity and duration of exercise.9 this recommendation dictates an intake of 500 800g/d which is an enormous dietary challenge in itseli'. because o f this, some of the required cho (about 30%) should come from foods or fluids with a high glycaemic index, allowing less bulk and faster absorption. in the case of athletes trying to ‘make weight’ or on weight control programs, their cho intakes need not be compromised. it is the total energy that needs to be reduced through protein and fats. this is because the cho taken in is almost entirely used in glycogen syn­ thesis or is oxidised. only i f the cho intake is so excessive that glycogen saturation occurs and if cho cannot be oxidized for energy generation will the excess be converted into fat.12 this de novo lipogenesis prevents the increase of body fat stores despite the high cho intakes (500g) o f some individuals. what is sometimes misunderstood by athletes when changing to a high cho diet is that there is increased glycogen storage and a concurrent increase in the uptake of water. glycogen is stored with about 2-4 times its weight in water.13 the use of skinfold measurements can reassure the athlete that fat mass is not being gamed. the role that protein has played in various sports has also been studied. according to lemon, there are increased protein needs particularly during strength training but only up to 1.2 1.7g/kg/d.b table 2 sum­ marises the recommended protein requirements of various athletes.11 in practice it is not always necessary or appropriate to ‘protein count’ every day. the protein requirements o f most sports will usually be met by an increase in the total food intake. new developments fats as an energy source because of the important role carbohydrates have played in enhancing muscle glycogen stores, the intake of fats have always been kept to a minimum. excess fat intake increases adipose tissue and can take up valu­ able dietary7 ldlojoule allowance that would otherwise be used for carbohydrates. in contrast to this there is now some interesting work being done on the effect of dietary fat on endurance exercise. it is thought that just as depleted muscle glycogen stores can reduce performance, so can depleted muscle triglyceride(tg) stores. these muscle tg stores maintain the muscle free fatty acid ( i'fa) pool that can be used as an ener­ gy substrate during endurance exercise particularly in a trained athlete. training enhances the utilisation of fats during exercise through increased muscle lipid oxidation.1415 according to newsholme10, both carbohy­ drates and fats are available as fuel sources simulta­ neously, with cho being more important initially and fat metabolism becoming important as glycogen stores are reduced. it is not only the presence but also the type of fat in the diet that is receiving attention. studies have exam­ ined the effect of medium chain triglycerides (mct) on exercise as they are believed to metabolise into the ffa pool more efficiently, thereby enhancing endurance performance in trained individuals. the greatest improvements have been found when mct’s are used in combination with cho.17 table 1 schofield equation for estimating metabolic rate in mj/d hi adults and children over 10 years of age. age equation men ' 1 0-18 (0.074 x wt) + 2.754 = bmr 1 8-30 (0.063 x wt) + 2.896 3 0 -6 0 (0.048 x wt) + 3.653 over 60 (0.049 x wt) + 2.459 women 10 18 (0.056 x wt) + 2.898 18 30 (0.062 x wt) + 2.036 30 60 (0.034 x wt) + 3.538 over 60 (0.038 x wt) + 2.755 table 2 suggested protein requirements o f various groups o f athletes general sports activity 1 g protein /kg body weight strength-training athletes (aim for the high end of the range during muscle gain periods) 1.2 1.5 g protein /kg body weight endurance training athletes (aim for the high end of the range for very prolonged strenuous training) 1.2 1.6 g protein /kg body weight adolescent and growing athletes 2.0 g protein /kg body weight pregnant athletes extra 10 g protein per day in trimester two and three breast-feeding athletes extra 20 g protein /day sports medicine september 1997 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutritional supplements one of the more controversial challenges for olympic athletes is the use of nutritional enhancers or supple­ ments. almost every south african athlete is taking some supplement or another and in the experience of the author, most take far in excess o f the recommended dietary allowances (rda). there is increasing evidence that antioxidant vitamins and min­ erals may offer protection against the potentially dam­ aging free radicals that are generated dining exercise.'" consequently, athletes arc taking these nutrients as a precautionary measure. however, they should be encouraged to take foods that are nutrient dense and well balanced instead of general vitamin and mineral supplementation. it should be noted that indiscrimi­ nate use of mineral supplementation can have adverse health effects such as gastro-intestinal disturbances."’ because of the high demands of exercise on the body, it is becoming more apparent that high performance athletes should be recognised as a nutritionally ‘at risk’ group. another controversial nutritional enhancer receiving much attention is creatine, especially as it is not on the international olympic committee (ioc) list of banned substances. it plays a role in skeletal muscle metabo­ lism particularly in high intensity, intermittent exer­ cise. creatine can be obtained from foods (meat,fish) or produced endogenously in the liver, kidney and pan­ creas.'1’ in the muscle it is found w’ith a high energy phosphate bond phospho creatine(pcr), or in its free form. in brief, high intensity exercise such as sprints in swimming, cycling or running, the availability of pcr within the muscle may be the limiting factor in perfor­ mance. it is thought that depiction in pcr may causc a reduction in the rate of adenosine triphosphate (atp) resvnthesis at the required rate. supplementation with oral creatine may thus increase the available pcr.21 it is also a ph buffer and resists the acidosis consequence of high intensity exercisc. creatine supplementation is being used by some of our olympic athletes and its efficacy has recently been established in the field. (carter r, “ personal commu­ nications” ). there are however, too few conclusive stud­ ies available demonstrating significant increases in performance to warrant recommendation. summary an olympic athlete faces many challenges in his/her quest for success. deciding on what, when and how much to eat is just one of them. athletes are constant­ ly faced with new dietary products, new food recom­ mendations and conflicting advice. sorting through the information is a difficult task. there is no substitute for hard w’ork, scientific preparation and a well balanced eating plan. references 1. w ilm ore jfi. b ody weight standards and a th le tic perfor­ mance. jn : b row nell k d , r odin j, w ilm ore j h . eating. body weight and perform ance in athletes: lea & febiger. ph iiadelph ia. 1992:315-329. 2. ross vvd. crawford sm. k e rr d a . ward r. bailey d a . m irw ald r m . r ela tion sh ip o f the body mass index with skinfolds. girth and bone breadths in canadian men and women aged 20-70 nears. a m j phus a n th ro p o l 1988: 77:169-73. 3. johnson fe. r ela tion sh ip between body com position and anthropom etry. h um an b io 1982: 5:221-5. 4. k e rr d a . body com p osition in athletes. sport h ealth 1993: 1 1 (1 ): 35-37.' 5. telford rj). egerton wj. h ahn a g , p a n g pm . skinfold measures and weight c o n tro l in elite athletes. excel 1988: 5:21-24. 6. warwick p\i. p re d ic tin g food energy requirem ents from estim ates o f energy expenditure. a u s t j n u tr d ie t 1989: (4 6 ) suppl. 7. b u rk e l. the c o m p le te g u id e to f oo d fo r s p orts perform ance: a llen & unwin p ty ltd, 1992: 33. 8. lem on p w r . effect o f exercise on protein requirements. j sports s ci 1991a: 9 (s p e c ia l is su e ): 53-70. 9. c ostill d l . carbohydrates fo r exercise: dietary demands for op tim a l performance. in t j sports med 1988: 9: 1-18. 10. coyle ef, coggan .1 r. effectiveness o f carbohydrate feeding in delaying fatigue d uring prolonged exercise. sports med 1984: i: 446-58. 11. b u rk e l. the c om p lete g u id e to f ood f o r s p orts perform ance: a lle n & unwin p ty ltd. 1992: 35. 12. acheson k j, schuty. y, bessard t, a n a nth a ram an k. flatt jp. jequ ier e. glycogen storage capa city and de novo lipo genesis during massive carbohydrate overfeeding in man. a m j clin n u tr 1988: 48: 240-7. 13. olsson k e . saltin b. variations in to ta l body w ater with muscle glycogen changes in man. a c ta physiol scand 1970: 80: 11-18. 14. m u oio d m . leddy j j , h orvath p j . aw ad /l b . pendergast d r . effect o f dietary fat on m etabolic adjustm ents to m ax­ im a l vo., and endurance in runners. med s ci sj>orts exerc 1994: 26: ( 1 ) 81-88. 15. r o b erts k m . n ob le e g . hayden d b . t a y lo r aw. lipoprotein lipase a ctiv ity in skeletal muscle and adipose tissue o f m arathon runners a fter sim ple and com plex ca r­ bohydrate rich diets. e u r j a p p l physiol 1988: s7: 75-80. 16. new sholm e e a . c on trol o f m etabolism and the in tergration o f fuel supply for the m arathon runner. in : k n uttgen h g. vogel j a . poortm a n s j r (e d s ) b iochem istry o f exercise. hum an k in etics publishers inc. cham paign. 1983: 144 150. 17. van zy l cg, lam bert ev. hawley j a . noakes t d . dennis sc. effects o f m edium chain triglyceride ingestion on fuel m etabolism and cycling performance. j a r 1 9 9 6 :8 0 (6 ) -.2217-2225. 18. k a n te r mm. w illiam s m h . a n tioxid en ts. c a rnitin e and choline as pu ta tive ergogenic aids. in t j sj>orls n u tr 1995: 5: s120-31. 19. lukaski hc. m icron u trien ts (m agnesium , zinc and cop­ p er) : a r e m ineral supplem ents needed fo r a th letes? in t j s ports n u tr 1995: suppl ( 5 ) : s74-83. 20. balsom p d . soderlund k . e k b lom b. creatine in humans with special reference to creatine supplem entation. sports med 1994; 18 ( 4 ) : 268-280. 21. g reenh a ff p l . creatine and its applica tion (ts an e rgogenic a id . in t j sports n u tr 1995: suppl ( 5 ) : s 10 0 -1 10. cd 22 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) g len barr pecialist publication glenbarr publishers private bag x14, parklands 2121. tel: (011) 442-9759 fax: (011) 880-7898 south african journal of sports medicine vol a nd c july ib m s 0 / > f r , r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) enrollment form i am interested in attending the first south african podiatry c ongress on o ctober 4, 1997, at the volkswagen conference centre, midrand. first name: ............................................... surname: .................................................... title: ............................................................. ad d r e s s :....................................................... ................................. code: ........................ tel: ........................... fax: .......................... if you wish to present a paper, please send your resume and presentation to the s.a.p.a. executive p.o. box 1011 rosettenville 2130 to arrive not later than september 1, 1997. assisted travel for accepted papers. cost s.a.ra. member r100,00 non-s.a.p.a. members r140,00 receipt given on request. only cheques or postal orders. all paym ents to be made to the s.a. podiatry association. i enclose my cheque of r ............................. post to: mckenzie dickerson int. p.o. box 53101 troyeville 2139 tel: (011) 402-3240 • fax: (011) 402-0164 final programme will be posted to all dele­ gates august/september. the south african podiatry association the first south african podiatry congress october 4, 1997 volkswagen conference centre m id rand 08:00 18:00 o v e r 20 supplier exhibits for the podiatry profession refreshments & 4-course lu n c h best paper award congress organized by m ckenzie dickerson international 24 sports medicine september 1997 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) oas/to / cmps ba tired of hotels? in the heart o f camps bay this beautiful villa invites you to share its panoramic sea & mountain views. treat yourself & your overseas visitors to the privilese & lu xury o f this outstanding villa in an exceptionally quiet street above the bay hotel. outstanding villa in an s5 an b0 wa'tin? ° n ic0 for your arrival simply relax and enj°v watching the sun setting over h j r s r ' .uce y0ur vlsltors t0 a trad,tional south african braai or order the menu o f your choice to be delivered to you at msangasanga. y special corporate offer upstairs & downstairs each w ith ow n lounge, dining room + kitchen downstairs: 2 bedroom s (b o th en suite) sleeps 4 • r800 pd. upstairs: 3 bedroom s (3 baths 2 en suite) sleeps 6 • r1200 pd. or 5 bedrooms (5 baths 4 en suite) • r2000 pd. • villa serviced daily • braai facilities • 10 min to waterfront secure parking for 4 cars swimming pool catering services available • phone + fax facilities • laundry service • close to beach, shops & theatre for further information: tel: 27 (0)11 442-9759 • fax: 27 (0)11 880-7898 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasma print ready file 1 sasma abstracts oral presentations index title name surname abstract title o01 ms sarah arnold unilateral transtibial amputees display asymmetry in muscle activity and ground reaction force during sit-tostand-to–sit o02 ms marelise badenhorst players’ experiences of the immediate management of rugby-related acute spinal cord injury in south africa o03 ms marelise badenhorst mental health profiles of para-athletes in south africa o04 mr getachew basha determinants of physical activity participation in ethiopian people with disabilities. o05 dr jill borresen prevalence of lifestyle-related risk factors for noncommunicable diseases in 1st year university medical students: preliminary data from the help-health study o06 ms micaela brown hamstring/quadriceps ratio and hip abduction strength imbalances in amateur rugby union players with or without previous injuries o07 dr james brown the silver lining of the high rate of concussions in stellenbosch koshuis rugby competition o08 mrs susan crumpton the development of the maroon health passport: a novel medical platform to identify lifestyle-related alerts in the staff and student population of stellenbosch university o09 mr eprem tamrat desalegn incidence and etiology of volleyball injuries in ethiopia: a search for amhara regional state clubs and young players. o10 mr adiele dube physical activity practice among undergraduate students in the faculty of health sciences o11 mrs kirsty elliott does maturation phase affect physical performance and anthropometry in girls? o12 mr robert evans improvements in cardiovascular efficiency over 24weeks of rehabilitation using robotic locomotor training in persons with spinal cord injury (sci). o13 ms tanya green weekly and seasonal patterns of daily wellness monitoring of the 2019 varsity cup winners o14 dr lara grobler health perception of students from the maroon health passport at stellenbosch university: results from the sf36 questionnaire o15 mr handré hay there is a high incidence of exercise associated muscle cramping (eamc) in “comrades” runners a safer study in 84 117 race starters 2 o16 dr martin heine cardiac rehabilitation delivery in africa o17 mr nceba hene more than 70% of employees in a south african financial institution have modifiable risk factors for noncommunicable disease (ncd) – project sway o18 ms nicole hinze unilateral transtibial amputees are most satisfied with a prosthesis that utilise a novel linkage system: a randomised controlled trial o19 mr charl janse van rensburg is the risk of injury in a super rugby season increased by injury in the preceding season? o20 mrs audrey jansen van rensburg measures to reduce illness burden during the super rugby tournament should focus on preventing infective respiratory tract illness – a prospective study involving 103979 player days o21 ms esme jordaan there is a non-linear relationship between total annual training distance and overuse injuries in cyclists: a crosssectional study in 21617 recreational cyclists o22 ms aayesha kholvadia exercise and laser therapy for knee osteoarthritis: a survey to understand the knowledge and attitudes of medical and allied health practitioners o23 ms lize kroon a history of multiple chronic diseases is associated with muscle strain injuries in runners: a cross-sectional safer study in 76654 runners o24 ms therese leahy injury surveillance in school rugby union in ireland o25 mrs desiree maartens physical activity and risk factors for chronic noncommunicable disease in relation to disease severity in patients with ms – a cross sectional survey o26 mrs sweetness jabulile makamubeteck influence of an exercise program on perceptions and knowledge of modifiable risk factors for non-communicable diseases o27 dr habib noorbhai the batting backlift technique in cricket: what is the consensus at all skill levels? o28 dr sibusiso ntuli ligament injuries occur in every match during the super rugby tournament (2013 2016) o29 mrs charne scott performance and anthropometrical differences between sexes at the onset of puberty o30 dr nicola sewry there is a high rate of medical encounters (1 in 50 runners) during the 90km “comrades” ultra-distance race a safer study in 84 117 ultramarathon runners o31 mr sean surmon perceptions of training load and wellness monitoring of stellenbosch university high performance student-athletes o32 ms sonja swanevelder are training/running history, chronic diseases and medication use risk factors for injury prone runners? a safer study in 75421 race entrants o33 dr jason tee pacing characteristics of whole and part-game players in professional rugby union 3 o34 dr jason tee operationalising professional expertise: effective injury prevention by a multidisciplinary team working in professional rugby o35 prof johan van heerden profile of participants in the 19th world transplant games o36 dr riaan van tonder presenting features of female collegiate sports related concussion: a descriptive analysis o37 ms tamrin veldsman the relationship between physical activity and left carotid intima-media thickness among educators in south africa: the sabpa study o38 dr candace vermaak health promotion in individuals with spinal cord injuries: what is standing in the way of enhancing physical activity? o39 mr carel viljoen acute injury-related medical encounters (mes) are 3.9 times more common than illness-related mes in mass community-based trail running events: safer study in 2428 race starters o40 mr carel viljoen over 14% trail runners report an overuse injury in a 12month period, mostly affecting the knee and anterior thigh: a safer study in 2824 race entrants o41 mr carel viljoen exercise associated muscle cramp (eamc) is almost twice as common among 21.1km compared to 56km runners – a safer study in 76654 runners o42 mr jonah young a history of multiple chronic diseases is associated with achilles tendon injuries in runners: a cross-sectional safer study in 76654 runners clinical case presentations index title name surname abstract title c01 mrs emmari carstens an integrated approach to longstanding lateral foot pain in tri-athlete c02 ms tanya green a multistructural knee injury in a female field hockey player c03 dr melissa janse van vuren case report: an unexpected cause of leg pain in a 42 year old endurance runner c04 dr willanie sadie persistent pain following ankle sprain: an unusual presentation of an osteoid osteoma c05 dr craig thompson case report: a complicated shoulder dislocation in a young university rugby player 4 poster presentations no name surname abstract title p01 nicolaas abel an investigation of the knowledge of south african high school rugby coaches on concussion and the return-to-play protocol with the aid of a validated questionnaire p02 marius bester changes in heart rate variability while exercising in humid and high temperatures p03 christo bisschoff the influence of match characteristics on post-match heart rate variability of male badminton players p04 jill borresen 66% of 1st year university medical students report low habitual physical activity levels p05 adele broodryk the psycho-hormonal effects of aerobic fatigue on collegiate female soccer players p06 robyn burrows the effect of sports massage on lactic acid clearance during recovery from anaerobic exercise. p07 tanya camacho comparative upper-quarter posture analysis of female adolescent freestyle swimmers and non-swimmers p08 isaac chauke dermatological conditions in recreational athletes participating in a mass community-based running event p09 ben coetzee relationships between inand post-match heart rate recovery and heart rate variability of african badminton players p10 steve den hollander proficient tackle and ruck technique in rugby: a review p11 camille du plessis head and neck injuries sustained during the super rugby tournament: a prospective study involving 6520 player hours p12 adiele dube work-related barriers encountered by the football medical team in eswatini p13 robert evans blood pressure responses over 24-weeks using robotic locomotor training and activity-based training in persons sci. p14 daniel garnett injury and illness epidemiology surveillance at the indian ocean island games 2019 p15 philippe gradidge a description of cardiovascular disease risk factors in a sample of factory workers in johannesburg p16 philippe gradidge the ukumela impilo study to interrupt sedentary behavior and improve cardiovascular health p17 henriëtte hammill the effects of foam rolling and stretching as recovery tools on power output, mood state, muscle stiffness, and muscle pain p18 martin heine “i am active and healthy, so i don’t need to make lifestyle changes!” a short report of clinical markers of “risk” for ncd’s versus health and physical activity perceptions in a low-resourced setting. p19 shona hendricks eccentric knee flexor and hip abduction and adduction strength in professional male footballers p20 neil isaacs the kinetics and kinematics of the rotary backlift p21 neil isaacs the kinetics and kinematics of the rotary downswing in batting 5 p22 christa janse van rensburg exercise may decrease syncope secondary to postural change in females with ra: pilot study p23 aayesha kholvadia exploring the efficacy of low level laser therapy and exercise for knee osteoarthritis p24 dimitrje kovac altered thoracic spine kinematics as a potential cause of low back pain in rotational-sport athletes: a case study p25 lovemore kunorozva a five year clinical audit of concussive injuries in collegiate male rugby playersa stellenbosch university experience p26 dominique leibbrandt creating an evidence-based decision-making algorithm for the individualised and holistic management patellofemoral pain p27 warren lucas experiences of young south african gymnasts, parents and coaches about the health benefits of sport participation p28 fhulufhelo madzhiga the epidemiology of iliotibial band friction syndrome (itbfs), and risk factors associated with itbfs, in 21.1km and 56km distance runners p29 rowena naidoo the development of the c.r.e.s.t anti-doping intervention p30 wei qian the inherent dilemma and optimization path of the development of chinese sports industry p31 hashendra ramjee the epidemiology of muscle and tendon injuries during the super rugby tournament (2013 to 2015) p32 nicola sewry race distance, history of chronic disease and analgesic / antiinflammatory medication use are risk factors associated with overuse injuries in trail runners: a safer study in 2824 entrants p33 claire shackleton the effect of robotic walking and activity-based rehabilitation on secondary complications in individuals with spinal cord injury p34 org strauss the association between the mechanism of injury and the visual mri athology of acl injuries p35 johan van heerden work and family support among participants in the world transplant games p36 harry van wyk prevalence and type of injuries in south african trail runners 6 oral presentations o01: unilateral transtibial amputees display asymmetry in muscle activity and ground reaction force during sit-to-stand-to-sit sarah arnolda, lara groblera, wayne dermanb,c, phoebe runcimana, suzanne ferreiraa a department of sport science, faculty of medicine and health sciences, stellenbosch university, south africa, b institute of sport and exercise medicine (isem), division of orthopaedic surgery, faculty of medicine and health sciences, stellenbosch, south africa, c ioc research center, south africa presenting author email: sarnold@sun.ac.za background: the sit-to-stand (sist) and stand-to-sit (stsi) movements are repetitive daily activities which include loading of the hip, knee and ankle joints on each occasion. it is hypothesized that in amputees, compensation due to asymmetrical movements, can lead to joint overloading. this study aimed to describe the muscle activation levels and symmetry of vertical ground reaction force (vgrf) during the sist and stsi movements in unilateral transtibial amputees (utta). method: a total number of 25 participants were recruited for the studying, consisting of 12 utta and 13 controls. participants made use of their own prosthesis that they were familiar and comfortable with. surface electromyography (emg) and vgrf were recorded during ten continuous sit-to-stand-to-sit repetitions. results: muscle activation was significantly greater for utta lumbar erector spinae muscles (15.98±5.93%, p<0.05) during the sist and tibialis anterior (17.14±12.09%, p<0.05) during sist and stsi in comparison to the controls while affected side vastus lateralis activation was significantly lower (3.09±2.46%, p<0.05) than the unaffected and control sides. significantly higher vgrf was observed on the unaffected side (69.90±5.77 n.kg-1) of the utta compared to the affected (52.29±5.45 n.kg-1) and control sides (p<0.05). conclusions: lower muscle activation of the vastus lateralis and lower vgrf on the affected side could be an indication of poor knee control or the inability of the utta to load the prosthesis during the sist and stsi. this indicates the possible presence of a combination of muscle weakness and lack of confidence in the use of the prosthesis. the asymmetrical movement pattern may place the amputee at increased risk for joint degeneration (osteoarthritis) over time. it would be suggested that specific rehabilitation once an amputee receives their prosthesis be followed to help reduce this risk. keywords: amputee, sit-to-stand, stand-to-sit, muscle activity, asymmetry 7 o02: players’ experiences of the immediate management of rugby-related acute spinal cord injury in south africa marelise badenhorst1,2,3,4 evert verhagen1,2 mike lambert1,2 willem van mechelen1,2 james brown3,4 1division of exercise science and sports medicine, department of human biology, university of cape town, cape town, south africa 2amsterdam collaboration on health and safety in sports, department of public and occupational health and amsterdam public health research institute, amsterdam umc, vrije university amsterdam, the netherlands 3institute of sport and exercise medicine (isem), division of orthopaedic surgery, department of surgical sciences, faculty of medicine and health sciences, stellenbosch university 4international olympic committee (ioc) research centre, south africa presenting author e-mail address: mbadenhorst@sun.ac.za introduction: the optimal management of rugby-related spinal cord injuries (scis) is challenging developing country with socio-economic and healthcare inequities and a detailed understanding of the different barriers and facilitators to optimal care is needed. the aim of this study was to describe the perception of players, regarding factors related to the optimal immediate management of a catastrophic injury, in the periods before and after the implementation of the national rugby safety programme, boksmart. methods: the entire known population (n=113) of players who had sustained a rugby-related sci in south africa in the period of 1968-2015, as recorded in the boksmart/chris burger petro jackson players fund database (cbpjpf), formed the population of the study. ninety players agreed to participate and were included in the broader study. from these 90 semi-structured interviews, stratified purposive sampling was used to select interviews from players from a variety of socio-economic status and geographical areas for inclusion in this study. the final sample consisted of forty-eight (n=48) participants. results: prominent barriers in the period prior to the implementation of boksmart, such as inadequate equipment and the quality of first aid care appeared to have improved in the postboksmart period. however, the most frequently reported barriers, in the periods before and after the boksmart, were transportation delays after injury and admission to appropriate medical facilities. barriers were more prevalent in rural and lower socio-economic areas. conclusion: these barriers can be improved by applying an appropriate action plan and determining the correct lines of communication to emergency medical services, all of which are described within the mandatory boksmart course. the current findings should assist boksmart to focus their resources on strategies that ensure the dissemination of knowledge into practices on field. these findings may help shape education, awareness and future policy around the immediate management of rugby-related scis. 8 o03: mental health profiles of para athletes in south africa. marelise badenhorst1,2 phoebe runciman1,2,3 james brown1,2 lara grobler3 wayne derman1,2. 1institute of sport and exercise medicine (isem), division of orthopaedic surgery, department of surgical sciences, faculty of medicine and health sciences, stellenbosch university, cape town, south africa 2international olympic committee (ioc) research centre, south africa 3 department of sport science, faculty of education, stellenbosch university, cape town, south africa presenting author e-mail address: mbadenhorst@sun.ac.za introduction: a comprehensive understanding of para athlete health should include aspects such as mental health. however, there is a paucity of research investigating the mental health profiles of athletes with impairments in south africa, as well as globally. methods: data were collected during the 2019 national championships for athletes with impairments, which included athletes from provincial to international levels. mental health was measured with the trait component of the state/trait anxiety inventory (stai) and the kessler psychological distress scale (k-10). in both scales, lower scores indicate better mental health. on completion of the questionnaires, all athletes were given information of mental health support services. between-group differences were analysed using the mann-whitney u test or one-way anova. results: a total of 124 athletes, with a mean age of 26.7 (±9.2) years, were included in the study. the mean score for the stai was 39.2 (±9.3) units. a quarter (25.4%) of all athletes scored 45 and above, in line with scores of patients with a psychological / psychiatric diagnosis. there was a significant difference in stai scores between females (35.9±8.7) and males (40.3 ±9.3; p=0.02), and between married (32.6±8.9) and single (40.2±8.9; p=0.002) athletes. the mean score of the k-10 questionnaire was 20.4 (±6.4) units, with no significant difference between genders. k-10 scores were significantly higher in single than in married athletes (u =415.5; p =0.002). using a cut off score of ≥28 and ≥16 on the k-10, 12.2 % and 76.4 % of athletes had symptoms of distress, respectively. neither scale was associated with level of competition, sport code or impairment type. the k-10 and stai scores were highly correlated (r=0.64, p<0.001). conclusion: the study found high rates of psychological distress among athletes with impairments. these findings demonstrate a need to understand and identify possible mechanisms affecting mental health in this population. 9 o04: determinants of physical activity participation in ethiopian people with disabilities getachew kinati basha, 1, 2 johan van heerden 2 1 university of wollega, ethiopia, 2 department of biokinetics, exercise and leisure science, university of kwazulu-natal, south africa presenting author e-mail address: vanheerdenj@ukzn.ac.za introduction: encouraging physical activity participation is a public health imperative for all individuals but more so for those with a disability. hence, it is important that stakeholders have knowledge of potential facilitators and barriers for physical activity participation, in specific population settings. the purpose of this study was to determine the key facilitators and barriers and to physical activity participation and their-related factors among people with vision and limb disabilities in ethiopia. methods: a descriptive questionnaire survey was done among individuals (n=334) with visual and limb impairment, aged between 15 and 50 years age, of both genders living in urban and suburban areas of ethiopia. multiple linear regression modelling was performed to identify key facilitators and barriers to physical activity and a pearson chi-square test was subsequently done to establish associations between related demographic variables and the individual items of identified facilitators and barriers. results: time constraint and engagement was identified as a significant (p≤ 0.05) key barrier and facilitator, respectively for physical activity participation. not being able to find the time to be physically active was associated with the female gender (38.1%; p≤0.05), the age category of 31-40 years (52.6%; p≤0.05), a diploma qualification (52.6%; p≤0.05) and aetiology of disability (50.0%; p≤0.05). engagement factors were weight-loss associated with females (71.7%; p≤0.05), while weight maintenance, wanting to be physically fit and enjoying the challenge was associated (p≤0.001) with all age groups and levels of education. weight maintenance was also associated with both disability type (p≤0.05) and cause of disability (p≤0.05), while the latter was likewise associated (p≤0.05) with enjoying the challenge. the modelling process showed that negating “time constraint” as a barrier to increasing physical activity participation would be more effective than facilitating “engagement” as a motivator for participation. conclusions: ethiopian stakeholders responsible for an action plan informing an awareness campaign to increase physical activity among people with limb and vision disability should primarily focus on educating individuals and employers to manage and decrease time constraints as a major barrier to physical activity participation 10 o05: prevalence of lifestyle-related risk factors for non-communicable diseases in 1st year university medical students: preliminary data from the help-health study jill borresen1, martin schwellnus1, martin bac2, debashis basu3, gerda gericke4, amanda talma2, paola wood5, kim nolte5, tanya camacho5, marianne schwellnus6 1sport, exercise medicine and lifestyle institute (semli), university of pretoria, south africa 2department of family medicine, university of pretoria, south africa 3school of health systems and public health, university of pretoria, south africa 4department of human nutrition, university of pretoria, south africa 5division of biokinetics and sport science, university of pretoria, south africa 6school of medicine, university of pretoria, south africa presenting author e-mail address: jill.borresen@up.ac.za introduction: with the prevalence of non-communicable disease (ncds) increasing, the majority of patients seen by healthcare professionals will be those with ncds and associated risk factors. the health behaviours of healthcare professionals influence their counselling practices, their credibility in delivering lifestyle-related messages, and their success in guiding behaviours in patients; yet little is published on healthcare professionals and students. the who identifies physical inactivity, unhealthy diet, harmful use of alcohol and tobacco use as key behaviours to address. this study explores the prevalence of these risk factors in 1st year medical students. methods: this is a cross-sectional, observational study in 284 consenting 1st year mbchb and bachelor of clinical medicine practice (bcmp) students at the university of pretoria (96 male, 188 female, mean age 19.9±2.7 years). the rapid eating assessment for patients (reap), frequency intensity time (fit) index of kasari, a subset of questions from global adult tobacco survey (gats), and the alcohol use disorders identification test (audit) were administered using smartabase (fusion sport ptyltd). outcome variables included prevalence (%) of low physical activity, low fruit and vegetable intake, smoking, and excessive alcohol consumption. chi square statistical test was performed to ascertain differences between male and female participants. results: 66% reported engaging in low levels of habitual physical activity (males 61%, females 68%; not significantly different (ns)); 34% usually/often eat less than 2-3 fruits (males 40%, females 31%; ns) and 31% usually/often eat less than 3-4 vegetables a day (males 28%, females 32%; ns). 8% report smoking (males 13%, females 6%; p=0.045) and 12% reflect harmful alcohol use (males 20%, females 8%; p=0.006). conclusions: these are preliminary data aimed at identifying lifestyle-related risk factors that should be addressed; thereby contributing to developing and implementing the healthy lifestyle programme for healthcare professionals (help-health). 11 o06: hamstring/quadriceps ratio and hip abduction strength imbalances in amateur rugby union players with or without previous injuries micaela brown, lyle kearns, andre pienaar, rowena naidoo discipline of biokinetics, exercise and leisure sciences, university of kwa-zulu natal, westville campus, south africa presenting author email address: micaelaashleybrown@gmail.com introduction: hamstring/quadriceps ratio (h/q) and hip abduction strength are important for performance and injury prevention in amateur rugby players. the strength relationship and balance of co-activation between the flexor, extensor and abductor muscles are important in articular stabilisation, efficacy of movement and the prevention of injuries. this study aimed to measure the h/q strength ratios and its relationship to hip abduction strength of the dominant and non-dominant leg; as well as to determine if there was a relationship between strength imbalances and previous lower limb injuries. methods: this descriptive, correlational design study, comprised sharks academy rugby players, in kwazulu-natal. fifty-nine players between the ages of 18 to 23 years, participated in this study. all participants completed an injury prevalence questionnaire and anthropometric (height and weight) measurements were taken. knee flexion, knee extension and hip abduction were measured using the pressure air feedback (pab®) system. descriptive (means and standard deviations) and inferential (t-tests and pearson correlation) statistics were used. (p≤0.05) results: a positive correlation between h/q ratio and hip abduction strength was found. no significant strength differences between dominant and non-dominant legs, as well as no correlation between the strength ratios and previous injuries were found. the players h/q ratio was sufficient to meet the minimal standards, however hip abduction strength was weak. conclusions: although the history of lower limb injuries did not correlate with current strength ratios, the data recorded identified the player’s strengths and weaknesses. this data is useful to improve lower limb strength monitoring. the findings highlight the importance to monitor lower limb strength and to help improve conditioning and rehabilitation programmes for the amateur rugby players. 12 o07: the silver lining of the high rate of concussions in stellenbosch koshuis rugby competition james craig brown 1,2, lindsay toyah starling1,2, keith stokes 3,4, pierre viviers 1,2, esme jordaan 2,5,6, sean surmon 1,2,7, elton wayne derman 1,2 presenting author email address: jamesbrown06@gmail.com 1 institute of sport and exercise medicine, division of orthopaedics, department of surgical sciences, stellenbosch university, cape town, south africa 2 ioc research centre, south africa 3 department for health, university of bath, bath, united kingdom 4 rugby football union, twickenham, united kingdom 5 biostatistics unit, medical research council, cape town, south africa 6 statistics and population studies department, university of the western cape, cape town, south africa 7 maties sport, stellenbosch university, stellenbosch, south africa introduction: collision sports, such as rugby union (‘rugby’) have a particularly high risk of injury. despite non-professional rugby players comprising the majority of the world’s playing population, there is relatively little research in this population. stellenbosch rugby football club (‘maties’), the official rugby club of stellenbosch university, represents one of the world’s largest non-professional rugby clubs, making this an ideal cohort for community level injury surveillance. the aim of this study was to describe the incidence and events associated with concussion in this cohort. methods: baseline demographics were obtained on the 807 male student rugby non-professional players who registered for the ten-week long 2018 season, which comprised 101 matches and 2 915 of exposure hours. all match-related injuries were captured by the medical staff of stellenbosch campus health service on an electronic form developed from the consensus statement for injury recording in rugby. results: the average age, height and weight of this cohort was 20±2 years, 182±7 cm and 88±14 kg, respectively. overall, there were 89 time-loss injuries, which equated to an injury rate of 31 per 1000 match hours (95% confidence intervals [cis]: 24-37), or about one injury per match. the most common injury diagnosis was “concussion” (n=27 out of 90 injuries, 30%), at a rate of 9 per 1000 match hours (95% cis: 6-12). the three most common mechanisms of concussion in the present study were performing a tackle (33%), accidental collision (30%) and being tackled (11%). conclusion: concussion was the most common injury in this population, at a rate that was six times higher than a comparable cohort in the uk. this might be explained by the training and vigilance of the club’s first aiders observing all matches for concussion. future studies should try to explain this high rate and subsequently reduce these concussions. 13 o08: the development of the maroon health passport: a novel medical platform to identify lifestyle-related alerts in the staff and student population of stellenbosch university s crumpton: institute of sport and exercise medicine, stellenbosch university, cape town, south africa; campus health service, stellenbosch university, south africa. p viviers: institute of sport and exercise medicine, stellenbosch university, south africa; campus health service, stellenbosch university, south africa. lara grobler: institute of sport and exercise medicine, stellenbosch university, south africa. w derman: institute of sport and exercise medicine, stellenbosch university, cape town, south africa; ioc research center, south africa. purpose:chronic non-communicable disease constitutes a rapidly escalating health burden in the south african population, thus there is a growing need to identify risk profiles in the young population to be able to modify these profiles with appropriate interventions. to determine the feasibility of implementation and ascertain risk profiles in young students, the maroon (maties risk of non-communicable disease) health passport was developed to collect self-reported data. methods:a pilot study was conducted on 600 staff and students from stellenbosch university to assess the feasibility of the data collection tool, and to determine its ability to identify lifestylerelated risk behaviours and medical conditions. the maroon health passport survey was created on an electronic platform, redcap® and comprises three sections: (1) demographics, (2) lifestyle behavioural factors, and (3) medical history. a selection of previously validated questionnaires was included in this survey. the link to the survey was distributed to the pilot sample via email for completion. results: 381 of 600 participants (64%) accessed the survey, with 234 completing the full survey (61.4% completion rate). 60% of participants were female, and 40% male. the average age was 28 years old (± 10 years; minimum age 18, maximum age 60). 64.2% of participants were students, with 79.7% being undergraduate and 20.3% postgraduate students. the staff participants (33.8%) were classified as academic staff (8.1%) or professional support staff (91.9%). both lifestyle-related risk behaviours and medical conditions or risks were identified in 54.6% of participants. 15% of participants had only lifestyle-related risk behaviours, whereas 1.3% had only medical conditions or risks. there were no risks identified in 29.1% of the participants. reasons for non-completion of the survey were identified and the tool amended accordingly. important data were determined regarding incentivising participants. conclusion:the results of this study suggest that the maroon health passport is able to effectively identify risk profiles in staff and students. this pilot study has also allowed for effective alteration of the survey and to understand factors relating to survey completion. 14 o09: incidence and etiology of volleyball injuries in ethiopia: a search for amhara regional state clubs and young players. et desalegn, phd candidate1, h j van heerden, dphil2 1. university of gondar, college of natural and computational sciences, department of sport science, gondar, ethiopia. email: ephrem123@gmail.com 2. university of kwazulu-natal, school of health sciences, department of biokinetics, exercise and leisure science, academic leader: research, south africa, durban. email: vanheerdenj@ukzn.ac.za introduction: in recent years in ethiopia, there is an increment of the number of participants in volleyball sport under clubs, projects and recreational programs. however, athletes are highly vulnerable for injuries because of a lack of protective equipment, suitable playing areas, medical facilities, efficient injury surveillance systems and skilled manpower (coaches).the aim of this study was to examine the incidence and mechanisms of acute and overuse volleyball injuries in ethiopia and to describe factors associated with injuries. methods: the injury incidence rate, severity, diagnosis and anatomical location of the injuries that occurred during practice and competition in a full season of 40 weeks were recorded prospectively on a weekly basis during the period 2015/16. a total of 323 volleyball players (168 female and 155 male) from amhara regional state clubs and youth teams were participated in the study. all players responded to a questionnaire on demographic variables (only at baseline), sports participation, use of preventive measures, and previous injuries and conducted baseline functional tests (balance, power and flexibility). volleyball exposure during training and matches was recorded for each individual player by the coach on a weekly exposure form. in the case of an injury triage nurses interviewed the injured player and recorded it on an injury registration form on a weekly basis. results: in the current study, the overall mean age of the players was 15.97 ± 2.94 years for men and 15.86 ± 2.33 years for women. in terms of team type, the age of youth players was 15.42 ± 1.92 years for females and 14.85 ± 1.05 years for males, and club players was 18.54 ± 2.81 years for females and 21.54 ± 2.98 years for male players. during the period of the study (10 months) the total sample (n=323) reported 188 injuries. it is notable that, injury rate in relation to age, the 323 players were divided into three age-related groups. of the 131 youth and club injured players, 118 (62.77%) players aged 14-16 years, 65 (34.57%) players aged 17-25 and 5 (2.66%) players aged more than 25. the injury rate in the age range of 14-16 players was statistically different in comparison to the injury rate to the other age groups (χ2=5.89, p≤0.05). both youth and club players, reported 188 injuries during a total exposure time 50 379 player-hours, comprising 43 566 hours of training (7 715 hours for club and 35 851 hours for youth players) and 6 813 hours of match play (1 004.5 hours for club and 5 808.5 hours for youth players). the overall injury incidence was 3.73 injuries/1000 player-hours, with 4.31 injuries/1000 playerhours for males and 3.26 injuries/1000 player-hours for females. regarding team type, 7.1 injuries/1000 player-hours was for club players and 3.02 injuries/1000 player-hours for youths. during match play the injury incidence was 27.59 per 1000 player-hours and 4.31 per 1000 player-hours throughout training periods. the rate of injury in game sessions was statistically different in comparison to training injury rate (χ2=16.1,p≤0.05). the result also revealed the rate of injury in game session was significantly different in club and youth players (χ2=9.14,p≤0.005) but there were no differences in relation to gender in both game and training sessions. during the season 167 (88.83%) were acute injuries and 21(11.17%) overuse syndromes. according to 15 physician diagnosis, the most common injury was the fingers (55 cases, 29.25%), followed by ankle (35 cases, 18.61%), knee (33 cases, 17.55%). significant difference was obtained between the anatomical parts (p≤0.05) and gender (p≤0.005). the severity of injuries was shown in terms of absence from competition or training after the injury. the rate of mild injuries was 53.19 % (100 cases), that of moderate injuries was 36.70 % (69 cases), and that of major injuries was 10.11 % (19 cases) (significant difference between them, χ2=35.18, p≤0.05). statistical differences between severities of injury in relation to gender was observed (female χ2=18.6,p≤0.05 and male χ2=17.19,p≤0.05). regarding the factors of injury, 57.45% (108 cases) was due to poor technique, 14.89% (28 cases) because of incorrect sprawls, 7.98% (15 cases) caused by stepping on others’ feet and 8.51% (16 cases) as a result of fatigue and significal difference was obtained between the factors of injuries (p≤0.05) but not gender (p>0.05). conclusions: this is the first large scale study of its kind in ethiopia and has established the epidemiology of injury related to volleyball. overall, the findings of this study revealed that the frequency of injury was high (58.2%) in the 2015/16 season of volleyball played. in this study male players were more injured than females 51.6% (97/188) and 48.4 % (91/188) respectively. but significant difference was not found between gender (p>0.05). interms of team type significantly youth players 126 (67.02%) were more injured than elites 62 (32.98%) (p≤ 0.05). injuries in both groups gender and team type were much more likely to occur in games than in practice. but, significance difference was found only between club and youth players (p=0.05). finger (29.25%), ankle (18.62%) and knee (17.55%) were the most frequent injured anatomical parts and significant difference was found between the overall anatomical sites (p≤0.05). sprain was clearly the most common injury in volleyball which accounted nearly about one third 31.38% (59/188) of all injuries with an incidence of 1.17 per 1000 player-hours followed by dislocation and laceration 21.27% (40/188) with an incidence of 0.79 per 1000 player-hours each and statistically significant between the type of injuries diagnosed (p≤0.05) but no significant difference between male and female players (p>0.05). in this prospective study, 10.64% (20 cases) left/right front and 11.7% (22 cases) back line club players and 19.68% (37 cases) back court and 17.55% (33 cases) center young players were vulnerable to injuries due to poor technique 57.45% (108 cases), incorrect sprawl 14.89% (28 cases), fatigue 8.5% (16 cases) and steps on other’s feet 7.98% (15 cases) during the execution of blocking, setting a ball for spikers and receiving first ball. statistically, significant difference was not obtained between players court position (p>0.05). in relation to degree of severity, more than half 53.19 % (100 cases) injuries were mild severe, 36.7% (69 cases) moderate and 10.1% (19 cases) were major severe. in this regard significance difference was found (p≤0.05). recommendations: in order to prevent players from musculoskeletal injuries, specific warming up, strength, proprioceptive, plyometric, balance and flexibility exercises for the muscles and joints of the upper and lower extremities of players should be incorporated in the training sessions. in addition, players should use preventive equipment during training and match periods. moreover, continuous injury surveillance and intervention is needed. 16 o10: physical activity practice pattern among undergraduate students in the faculty of health sciences adiele dube¹, morgan p. gundani² ¹department of health education, southern africa nazarene university, eswatini ² department sports science & coaching, national university of science & technology, zimbabwe presenting author e-mail address: dubea2567@gmail.com introduction: globally, research has revealed serious risks associated with physical inactivity can which include cause deaths worldwide; coronary heart diseases, diabetes, and colon or breast cancer. this study sought to compare the pattern of physical activity practice, benefits and perceived barriers of physical activity among first year and final year undergraduate students. methods: a cross-sectional study was conducted from the southern africa nazarene university’s faculty of health sciences. a total of 480 students were drawn from the 4 departments; nursing and midwifery, medical laboratory sciences and pharmacy. physical activity was measured using the international physical activity questionnaire (ipaq). descriptive statistics and bivariate analysis; pearson chi-square test, fisher exact test were employed for data analysis using spss v23.0. results: sedentarism were predominantly affecting females in the 4th years compared to their 1st year counterparts (p= 0.001). more than 15% of the male students from 1st and 4th years were physically inactive. time limitation and lack of accessible and suitable sporting facilities were identified by both classes as the most barriers to physical activity (p= 0.001). 83% of the participants stated that physical activity promotes and maintains health. the results showed the correlation between physical activity and sitting time (p = 0.001). conclusion: the main risk groups for physical inactivity were female students. the university should incorporate active physical health lifestyle in the curriculum in order to increase levels of physical activity during medical school training. 17 o11: does maturation phase affect physical performance and anthropometry in girls? kirsty elliott 1,2, james clark 1,2, charné scott 1,3, cassidy grobler 3, mariska fisher 3, charl janse van rensburg 4 1sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, 2division of biokinetics and sports science, department of physiology, university of pretoria, 3department of sport and leisure studies, university of pretoria, 4biostatistics unit, south african medical research council presenting author e-mail address: kirsty.elliott@semli.co.za introduction: there is limited research on how maturation during stages of puberty affects anthropometry and physical performance in active females. therefore, the aim of the study is to compare anthropometric measures and physical performance in active females at different maturation stages during puberty. methods:118, physically active females (age: 11.9 ± 0.8 yrs.), were classified into 3 groups according to maturity status (mirwald equation): pre-peak height velocity (pre-phv; n=37), peak height velocity (phv; n=52) and post-peak height velocity (post-phv; n=29). chronological age, anthropometry (height, weight, body fat %, bmi (body mass index), arm span, seated height) and performance tests (grip strength, vertical jump, prone bridge, modified sit and reach) were compared between the groups, using a one-way anova. results: significant (p=0.05) between-group differences were found for chronological age (prephv 11.05 ± 0.52; phv 11.90 ± 0.50; post-phv 12.79 ± 0.41 yrs.) and all anthropometric measures (height, weight, body fat %, arm span and seated height) except for bmi (prephv=17.6 ± 2.7; phv group=19.0 ± 2.4; phv=19.02 ± 2.4; post-phv=21.0 ± 2.8; p=0.0001) for performance tests: absolute isometric handgrip strength was significant between maturation groups, (pre-phv: 18.20 ± 3.96 right,17.00 ± 3.80 left; post-phv: 28.05 ± 5.79 right, 25.76 ± 5.32 left (kg)(p=0.0001)), but strength relative to body weight was not significant (r: p=0.2933 and l: p=0.4611) conclusions: the main finding is that, as females mature during the stages of puberty, there are anthropometric changes (larger body size), but not concomitant changes in physical performance. therefore, practitioners could group pubertal girls of similar body size together to compete and train with one another in activities that don't require absolute strength. 18 o12: improvements in cardiovascular efficiency over 24-weeks of rehabilitation using robotic locomotor training in persons with spinal cord injury (sci). robert evans1, claire shackleton1, sacha west 2, laurie rauch1, wayne derman3,4, yumna albertus1 1 division of exercise science and sports medicine, department of human biology, faculty of health science, university of cape town, cape town, western cape, south africa 2 department of sports management, cape peninsula university of technology, cape town, western cape, south africa 3 institute of sport and exercise medicine, division of orthopaedic surgery, faculty of medicine and health sciences, university of stellenbosch, cape town, south africa. 4 ioc research centre, south africa presenting author e-mail address: robertevanssa@gmail.com research objective: evaluate changes in cardiovascular efficiency and walking economy during robotic locomotor training over a 24-week intervention in persons with sci. design: single group, repeated measures design. setting: therapy & beyond rehabilitation centre walking with brandon foundation participants: volunteer sample of 8 participants, aged 19 – 60 years, with chronic (>1 year) traumatic motor incomplete sci (c1-c8; asia c-d). interventions: the rlt intervention involved 60-minute sessions, three times per week, over 24-weeks. rlt exclusively used the ekso gt exoskeleton. main outcome measures: heart rate hr (beats/min), six-minute walk test – 6mwt (m) and total heart beat index – thbi (beats/m). results: mean hr whilst performing the 6mwt did not vary significantly over the course of the intervention. the distance walked during the 6mwt increased significantly from baseline (68.3 ± 11.3m) to 6-weeks (83.5 ± 8.1m), 12-weeks (98.3 ± 7.5m) and 24-weeks (109.9 ± 19.7m) (p < 0.05). the increased distance walked at 6-weeks with a hr comparable to baseline values, resulted in an improvement in the thbi from 11.1 ± 2.6 at baseline to 7.5 ± 2.8 beats/m walked at 6-weeks (p < 0.05). this improved efficiency of walking stabilised and was maintained from 6 to 24-weeks. conclusions: after 6-weeks of rlt, participants were able to walk greater distances during a 6mwt without increasing their heart rates from baseline values, resulting in a lower thbi. improved walking efficiency can be attributed to two factors, firstly an improved economy of walking via a learning effect with the exoskeleton and secondly improved cardiovascular fitness due to the aerobic training involved. 19 o13: weekly and seasonal patterns of daily wellness monitoring of the 2019 varsity cup winners lindsay starling1, 2, esme jordaan2, 3, 4, tanya green1, 2, 5, pierre viviers1, 2, 5; wayne derman 1, 2; james c brown1, 2 1. institute of sport and exercise medicine, division of orthopaedics, department of surgical sciences, stellenbosch university, cape town, south africa 2. ioc research centre, south africa 3. biostatistics unit, medical research council, cape town, south africa 4. statistics and population studies department, university of the western cape, cape town, south africa 5. campus health service, stellenbosch university, south africa introduction: athlete monitoring is particularly important in university student-athletes who have academic stressors additional to their training. the stellenbosch rugby football club (maties) team take part in a prestigious university competition, the varsity cup, between the start of february and mid-april of each year. the varsity cup competition consists of matches every monday night and thus teams have fairly consistent weekly training and travel plans. thus, the aim of this study was to assess if the team displayed similar weekly patterns in their wellness measurements over the period of the competition. methods:during the 71 days of varsity cup, the 43 squad members to respond daily on a 5point likert scale for sleep quality, overall stress levels, recovery, body soreness, readiness to train. the patterns in the individual responses for the stressors versus time were inspected, smoothing the data using nonparametric penalized b-splines. subsequently, the data was grouped into days of the week and generalized linear modelling compared the daily averages for each stressor, incorporating a correlation for the players. overall and pairwise test results were provided. results and conclusion:overall, 74% of all possible daily responses were completed by the squad. for all stressors (sleep quality, recovery, body soreness, readiness to train) except overall stress levels, there was an overall difference in mean scores for the weekdays (p<0.001). specifically, most of the average scores for monday and sundays were significantly higher compared to the other days of the week (p<0.05), indicating a clear weekly pattern. there was no weekly pattern for overall stress, but the fitted spline indicated a pattern over the season. in conclusion, these descriptive analyses indicate that monitoring of sleep quality, recovery, body soreness, readiness to train might be sensitive to within-week changes, but that overall stress might be more useful indication of response over the entire competition period. 20 o14: health perception of students from the maroon health passport at stellenbosch university: results from the sf36 questionnaire lara grobler1, pierre l, viviers1,2, wayne e derman1 1institute of sport and exercise medicine, stellenbosch university, south africa; ioc research center, south africa. 2campus health service, stellenbosch university, south africa presenting author e-mail address: lgrobler@sun.ac.za purpose: it is prudent that the ncds and lifestyle risks in the south african student population be described, in order for targeted intervention to be timeously implemented. the aim of the current study was to investigate the perceived wellbeing of a sample of the stellenbosch student population by means of the sf36 short questionnaire. methods: this study forms part of the maroon health passport, which constitutes a larger and more complete survey covering demographics, lifestyle and behavioural factors and medical history. the survey was distributed to students on stellenbosch university campus between october 2018 and july 2019. students completed the survey on an electronic platform, redcap. scores range between 0 and 100 with higher scores indicating better perception of health better scores. sub-categories physical functioning, social functioning, role limitations (physical problems), role limitations (emotional problems), mental health, energy/vitality, pain and general health perception was calculated from the results. results: the survey was completed by 174 students (77 men and 97 women) with a mean age of 21 years (range: 18 years to 29 years). overall the men and women scored similarly in all sections of the sf36. the lowest average score was found for energy/fatigue levels (women = 50±17, men = 59 ± 14), whereas the highest score was found for physical function (women = 95±14, men = 94 ± 19). discussion: the findings of this study suggest i) the general well-being of the student population is described as “good” and is similar to that described for an age matched population previously described. and ii) low scores for sections relating to energy/fatigue, role limitations due to emotional health, and mental health is of concern and should be addressed in future interventions. 21 o15: incidence of exercise associated muscle cramping (eamc) in “comrades” runners a safer study in 84 117 race starters handre hay 1, nicola sewry 1,2, carel viljoen 3, jeremy boulter 4, martin schwellnus 1,2 1 sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa, 2 international olympic committee (ioc) research centre, south africa, 3 sport, exercise medicine and lifestyle institute (semli) and department of physiotherapy, faculty of health sciences, university of pretoria, south africa, 4 medical director, comrades marathon presenting author e-mail address: carel.viljoen@up.ac.za introduction: exercise associated muscle cramping (eamc) is a common clinical syndrome that requires medical attention during and after endurance running events. the incidence of eamc during the 90km “comrades” marathon has not been reported. the aim of this study was to document the incidence of eamc in runners participating in the “comrades” ultramarathon race (2014–2018). methods: a retrospective clinical audit, involving 84 117 race starters, was conducted from data collected during the 90km “comrades” ultramarathon race in south africa. medical encounters (mes) (moderate and serious life-threatening), were collected by medical doctors during and immediately after the event. data were retrospectively coded using the 2019 consensus statement definitions. the main outcome variables were: overall crude incidence rate (ir per 1 000 starters; 95% cis) for eamc, and prevalence (as a % runners with eamc) of symptoms of more severe eamc. results: the overall ir of eamc over the five year period was 3.1 (95% ci: 2.7 3.5) (n=259) (1 in 322 race starters). the crude ir varied by year, with the lowest ir reported in 2015 (ir=1.7; 95% ci: 1.1 – 2.3) and the highest reported in 2017 (ir=4.7; 95% ci: 3.7 5.7). the incidence of more severe eamc over the five years was 1.7 (95%ci: 1.4 2.0). the three most common presenting symptoms of more severe eamc (n=144) were associated nausea/vomiting (66%), fatigue/exhaustion (36%) and dizziness (13%). conclusions: the incidence of more severe eamc in runners participating in the 90km “comrades” ultramarathon (90km, ir=1.7), is double that compared to data from the 21.1km and 56km two oceans races (ir=0.91). factors associated with this high incidence require investigation, so that prevention strategies can be designed and implemented to manage the risk of eamc in “comrades” runners. 22 o16: cardiac rehabilitation delivery in africa martin heine1,2,3, karam turk-adawi4, marta supervia5, wayne derman1,3, pamela naidoo7,8,9, sherry grace10 1 institute of sport and exercise medicine, faculty of medicine and health sciences, stellenbosch university 2 division of physiotherapy, faculty of medicine and health sciences, stellenbosch university 3 ioc research centre, cape town, south africa 4 qatar university, doha, qatar 5 gregorio marañón health research institute, gregorio marañón general university hospital, madrid, spain 6 division of preventive cardiology, department of cardiovascular medicine, mayo clinic, rochester, usa 7 heart and stroke foundation, cape town, south africa 8 african heart network, cape town, south africa 9 department of psychiatry, faculty of health and medicine, stellenbosch university, cape town, south africa 10 york university; university health network, toronto, ontario, canada presenting author e-mail address: mheine@sun.ac.za introduction: the burden of non-communicable diseases (ncds), and cardiovascular disease (cvd) specifically, is growing exponentially in africa, at a rate exceeding that globally. cardiac rehabilitation (cr) is an established model of care designed to mitigate the burden of ncds, and cvd specifically. robust evidence from predominantly high-income countries demonstrates that cr is associated with a reduction in rates of cardiovascular mortality (by 26%) and rehospitalisation (by 18%), as well as increases in quality of life, while being cost effective. methods: availability, capacity and characteristics of cr services around the globe were evaluated through a first-ever international survey. where available, champions from each country with cr were enlisted to identify the number of programmes, and also to administer an online survey of these programmes, which assessed both patient capacity and programme characteristics. cr density was computed using global burden of disease study estimates for annual ischemic heart disease (ihd) prevalence, to characterise the number of cr spots available per patient in need per year. results: a total of 32 cr programmes were identified across 8/47 (17%) african countries (the lowest proportion of all who regions). raw unmet need ihd alone (considering zero availability in countries without cr) for africa was 1 383 858 spots. eighty percent of african programmes fulfilled the 20 structure and process indicators (e.g. assessment of risk factors) which were assessed in the survey. conclusions: these findings, particularly in the context of the projected accelerated increase in incidence of ncds in africa demonstrate cr capacity must be augmented massively. given the realities of the african context (e.g. lack of trained healthcare professionals, limited resources, geographical challenges, multi-faceted and complex burden of disease), how to do this feasibly remains to be determined. 23 o17: more than 70% of employees in a south african financial institution have modifiable risk factors for non-communicable disease (ncd) – project sway nceba hene 1, martin schwellnus 2,3 , paola wood 1 1 sport, exercise medicine and lifestyle institute (semli) and division of biokinetics and sports science, department of physiology, faculty of health sciences, university of pretoria, south africa 2 sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, south africa 3 international olympic committee (ioc) research centre, south africa presenting author e-mail address: ncebahene@hotmail.com purpose: non-communicable diseases (ncds) currently accounts for most deaths in south africa (55% of all deaths). understanding the prevalence of modifiable risk factors for ncds in a sub-population is vital to guide the planning of any future intervention programme to reduce the risk of ncd. the aim of this study was to determine the prevalence of modifiable ncd risk factors in employees of a privately funded health insurer in the financial sector in order to plan and implement a social media based ncd intervention programme (project sway). methods: in this descriptive observational cross-sectional analysis, data from 10655 employees (38.3% male; 61.7% female: mean age ± sd = 48.1 ± 11.5 yrs) were analysed. ncd risk factor data were obtained from health risk assessments that included self-reported questionnaire (demographics, medical history, physical activity and current smoking status) and clinical measures (height, mass, bmi, total cholesterol, random glucose, and resting blood pressure). the main outcome measure is the prevalence of ncd risk factors (% of employees). results: the prevalence of modifiable ncd risk factors were: consumption of <3 fruit / vegetable portions/day (88.7%); inadequate physical activity (75.9%; employees performing <150 minutes of moderate-intensity physical activity/week); bmi >25 (71.4%; overweight =33.8%, obese=36.8%); raised resting systolic (34.3%; >130 mmhg) and diastolic (52.1%; >90mmhg) blood pressure; cigarette smoking (18%) and raised total cholesterol (14%; >5.2 mmol/l). the prevalence of these risk factors was similar for males and females. conclusion: poor nutritional habits, inadequate physical activity and overweight/obesity are the principal modifiable ncd risk factors (>70% of the studied population). a planned social media based ncd intervention programme (project sway) to reduce lifestyle risk factors in this population should mainly target these three modifiable ncd risk factors. key words: non-communicable diseases, modifiable risk factors, bmi, physical activity, chronic disease, modifiable risk factors 24 o18: unilateral transtibial amputees are most satisfied with a prosthesis that utilises a novel linkage system: a randomised controlled trial nicole hinze 1, elton wayne derman 1, phoebe runciman 2 1 institute of sport and exercise medicine, department of orthopaedics, stellenbosch university, 2 institute of sport and exercise medicine, department of sport science, stellenbosch university presenting author e-mail address: nickyhinze@gmail.com objectives: this study describes the subjective ratings of prosthesis satisfaction and daily fatigue in a group of south african unilateral transtibial amputees (uttas) using a conventional solid-ankle cushioned-heel (sach) foot, a vari-flex energy storage and return (esar) foot and a novel linkage system pro-flex esar foot. methods: twenty uttas performed a standardized protocol using a different foot prosthesis every two weeks, in a double-blind, randomised cross-over order. after two weeks of acclimatisation, the participants completed the trinity amputation and prosthesis experience scales revised (tapes-r) and patient-reported outcome measurement information system (promis) questionnaires, which are validated, and use a seven-day recall period. the tapes-r questionnaire measures the subjective experience of wearing a particular prosthesis. the multiitem promis questionnaire measures the participants’ fatigue and subsequent effects on everyday living. results: the uttas in this study wore each prosthesis for 13 ± 3 hours per day. the uttas rated the novel pro-flex as significantly more comfortable (p = 0.031), useful (p = 0.00027) reliable (p = 0.0096) and satisfactory (p = 0.00013) compared to the sach, with also a higher rating in comfort (p = 0.55), usefulness (p = 0.51) and reliability (p = 0.68) than the vari-flex foot. uttas reported experiencing more fatigue which interferes with social activities (p = 0.034), task completion (p = 0.03), task initiation (p = 0.041) and self-efficacy (p = 0.029) whilst using the sach, compared to the vari-flex. however, uttas wearing the pro-flex reported an overall higher fatigue (p = 0.89) than when wearing the vari-flex. conclusion: the current study shows that uttas prefer the novel pro-flex foot over the variflex and sach (p < 0.05) foot. however, it is interesting to note that the pro-flex caused more fatigue in daily life than the vari-flex, which may be as a result of the increased energy required to control the more deformable pro-flex foot, due to the novel foot/ankle linkage system. more research is required to investigate this relationship. 25 o19: is the risk of injury in a super rugby season increased by injury in the preceding season? charl janse van rensburg 4, nicola sewry 1,2, martin p. schwellnus 1,2, 3, esme jordaan 4,5 1 sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, pretoria, south africa, 2 international olympic committee (ioc) research centre, south africa, 3 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa, 4 biostatistics unit, medical research council, parow, south africa, 5 statistics and population studies department, university of the western cape presenting author e-mail address: charl.jansevanrensburg@mrc.ac.za introduction: rugby union is a contact sport resulting in injuries, which may increase the risk of future injury. this study aimed to investigate whether a player who sustained an injury in a previous season, had a higher risk of sustaining an injury in the following season. methods: a prospective observational study in 686 elite south african rugby player seasons in the super rugby tournament (2014 2016). team physicians daily reported injuries sustained during match and training throughout the tournament (58 789 player-hours). to indicate the playing characteristics in the previous season 2 variables were coded to indicate if the player (1) played (pps), (2) was injured (ips) in the previous season. the model included season, pps, ips, season*ips, match and training hours for both previous and current season, and lastly position played in current season (forward/back). the incidence rates (ir; 95%ci) are reported for the ips groups (ips positive and ips negative). results: out of the 102 (2014), 109 (2015) and 109 (2016) with injuries in the current season, 40 (39%), 46 (42%) and 41 (38%) also sustained injuries in the previous season. the ir for the ips positive and negative groups were 10.7 (8.6–13.2) and 9.4 (8.2–10.8), which did not differ significantly. there was not a significant difference between the irs for forwards and backs, however the ir increased significantly for an increase in total match hours in current season, and decreased significantly for an increase in total training hours in current season (p<0.0001). player hours in previous season is marginally significant (p=0.041). the ips*season interaction was significant (p=0.021), with a significant difference only between 2014 and 2016 (p=0.006). conclusion: after adjusting for various factors, whether a player had previous injury did not increase their injury incidence rate for the current season. however, player load both in current and previous season may be important predictors. further investigation is required. 26 o20: measures to reduce illness burden during the super rugby tournament should focus on preventing infective respiratory tract illness – a prospective study involving 103979 player days audrey jansen van rensburg1, martin p schwellnus1,2,3, dina c (christa) janse van rensburg1, esme jordaan4,5, charl janse van rensburg4 presenting author e-mail address: audrey.jansenvanrensburg@up.ac.za 1 sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 2 international olympic committee (ioc) research centre, south africa 3 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa 4 biostatistics unit, medical research council, parow, south africa 5 statistics and population studies department, university of the western cape introduction: respiratory tract illness (rti) accounts for most medical consultations in elite athletes, but details of the type, clinical diagnoses and severity are lacking. this study aims to describe the incidence, diagnoses (clinical, specific) and illness burden of rti in rugby players during the annual super rugby tournament. methods: elite rugby players (n=1141) from 5 south african teams were followed over the 16week competition period for each year 2013-2017 (103979 player days). team physicians daily completed an illness log, with squad size and rti details: clinical diagnoses (infective/noninfective), specific diagnoses, and training/match days lost to rti. incidence rates (ir) (per 1000 player days; 95%ci) of rti (all, infective, non-infective) and specific diagnosis, illness burden (ib) (days lost/1000 player days) and days lost per single illness (days; 95%ci) were reported. results: rti accounted for 67.7% of all illness. the ir of infective rti (2.6; 2.3-3.0), was higher than non-infective rti (0.4; 0.3-0.6) (p<0.001). specific diagnoses was: 1) infective rti acute upper rti (2.0; 1.8-2.3; 45.4%), influenza (0.2; 0.1-0.3; 4.5%), acute lower rti (0.1; 0.1-0.2; 2.6%); 2) non-infective rti allergic rhinitis (0.2; 0.1-0.3; 3.6%), allergic sinusitis (0.2; 0.1-0.2; 3.4%). the ib of infective rti (3.3; 2.9-3.6), was significantly higher than non-infective rti (0.9; 0.7-1.1) (p<0.05). the ib for specific infective rti was highest for acute infective upper rti (2.0; 1.8-2.3), followed by influenza (0.4; 0.3-0.6), and acute infective lower rti (0.4; 0.3-0.5). days lost per single illness was highest for pneumonia (15.0; 8.4-24.7), acute infective lower rti (3.2; 2.2-4.4) and influenza (2.1; 1.52.8). conclusion: infective rti accounted for >58% of all illness, mostly presenting as acute infective upper rti (45.4%) resulting in the highest ib. however, days lost per single illness was highest for pneumonia and acute infective lower rti. measures to reduce the ib of rti should focus on preventing infective rti. 27 o21: there is a non-linear relationship between total annual training distance and overuse injuries in cyclists: a cross-sectional study in 21617 recreational cyclists esmè jordaan 1, martin schwellnus 2, fc du toit 3, jannelene killops 2 1biostatistics unit, south african medical research council; statistics and population studies, university of the western cape 2sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria; international olympic committee (ioc) research centre, south africa 3sport, exercise medicine and lifestyle institute (semli) and division of biokinetics and sports science, department of physiology, faculty of health sciences, university of pretoria, south africa presenting author e-mail address: esme.jordaan@mrc.ac.za introduction: training load is a risk factor associated with overuse injuries, but training load and overuse injuries in cyclists has not been well investigated. the aim of this analysis was to explore the relationship between annual self-reported training distance and overuse injuries in recreational cyclists participating in a mass community-based cycling event. methods: this cross-sectional study included data from the pre-screening medical questionnaire completed by 21 617 consenting race entrants for the 2016 cape town cycle tour, including demographics (age, sex), training variables the last 12 months (km/week, frequency of training per week, training speed), and overuse injuries in the past 12 months. 615 cyclists reported 644 overuse injuries. using the training data variables, an estimated total training distance (ttd) in the past 12 months (km) was calculated (reported weekly average distance x 52 weeks). the relationship between ttd (km) and injury rate (ir: % cyclists with overuse injury) was explored using non-parametric penalized b-spline curves and the generalized linear model. results: the overall overuse incidence rate was 2.8 (95%ci: 2.6-3.1). the average ttd was »5 000km per year. there was a significant non-linear relationship between ttd and overuse ir (p<0.01), with a relatively low ir (<3%) at ttd below 5 200km/year, a steady increase in ir up to a peak ir (4%) at ttd of 14 000km/year, and a decrease in ir at ttd > 16 600km/yr. there is a consistently higher ir for females compared to males over the range of ttd (p=0.012). there is a consistently higher ir for older cyclists (older than 50 years) compared to younger cyclists (50 years and younger) over the range of ttd (p=0.0003). conclusions: these results indicate that an increase in ttd increases the overuse injury rate, but after a point, the rate decreases as ttd increases. further investigations should be performed to investigate the reason for the eventual decrease in the injury rate. 28 o22: exercise and laser therapy for knee osteoarthritis: a survey to understand the knowledge and attitudes of medical and allied health practitioners a kholvadia, bhms, hms (hons), ma (hms); d constantinou, mbbch, bsc(med)hons, msc med, mphil, ffims, facsm; p j-l gradidge, b sp sc, b sp sc (hons), msc med, phd centre for exercise science and sports medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: a kholvadia (a.kholvadia@gmail.com) background: there is evidence on the use of modalities such as exercise and low level laser therapy (lllt) for the management of knee osteoarthritis (koa), and medical and allied practitioners play a vital role in prescribing these various modes of management. the purpose of this study was to assess the prescribing tendencies, attitudes and beliefs of south african medical and allied practitioners on five modes of modes of koa management. methods: a convenience sample of 413 medical and allied practitioners, including general practitioners (n=110), specialist practitioners (n=117), allied practitioners (n=158) and natural/ homeopathic practitioners (n=28) participated in this survey method descriptive study. a validated questionnaire was distributed electronically to a data base of practitioners with a 57.12% completion rate after six months of regular contact. descriptive statistics and frequency tables were calculated. the pearson’s chi square statistic was used for testing the relationship between deemed efficacy and deemed compliance of the pharmaceuticals, surgical interventions, homeopathic intervention, exercise therapy and lllt. all statistical significance as set at p<0.05. results: the highest percentage of practitioners recommending pharmaceutical or physical exercise therapy. however practitioners viewed the deemed efficacy of pharmacological interventions greater than that of exercise therapy and this trend was followed for deemed compliance of the two modes of therapy. practitioners (36%) recommended pharmacotherapy with significant efficacy (p = 0.001) and compliance (p = 0.000). however awareness of lllt as a management tool showed significant efficacy (p = 0.000) and compliance (p = 0.000) despite being recommended by <2% of respondents as a management tool. conclusion: although medical and allied practitioners were positive towards the use of exercise in the management of koa, their prescription tendencies did not always align with the deemed efficacy due to the effect of deemed compliance. therefore the dissemination of results warrants the gap between educating practitioners on various modes in the management of koa that addresses the structural, functional aspects of the disorder together with improved efficacy and compliance 29 o23: a history of multiple chronic diseases is associated with muscle strain injuries in runners: a cross-sectional safer study in 76654 runners lize kroon 1, martin schwellnus 2,3,4, paola wood 1, sonja swanevelder 5, esme jordaan,5,6 kim nolte 1 1 sport, exercise medicine and lifestyle institute (semli) and division of biokinetics and sports science, department of physiology, faculty of health sciences, university of pretoria, south africa 2 sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa 3 international olympic committee (ioc) research centre, south africa 4 emeritus professor, faculty of health sciences, university of cape town, south africa 5 biostatistics unit, south african medical research council 6 statistics and population studies department, university of the western cape purpose: the purpose was to determine risk factors associated with msi in recreational runners participating in a mass community-based running event 2012-2015 two oceans marathon. methods: online pre-race data from 76654 consenting runners (60.7 % for 21.1 km, 39.4% for 56 km) were analysed, using a cross-sectional observational study design. risk factors associated with msi were explored using multi-variate analyses reporting a prevalence ratio (pr) and level of significance (p≤0.05): runner demographics, race distance, training/racing history, medication use, symptoms, history and risk factors of existing chronic disease. results: a total of 2093 (3.34%) entrants reported msi. when comparing race entrants who reported a msi to those who did not, older age (>31yrs)(p<0.0001), male sex (pr=1.27; p<0.0001), and longer race distance (56km vs. 21.1km)(pr=2.09; p<0.0001) were associated with a higher prevalence of msi. independent risk factors associated with msi (adjusted pr for race distance, sex and age) were: increased years of recreational running (p<0.0001), history of cardiovascular disease (cvd) (pr =1.40; p=0.0011), symptoms of cvd (pr =1.49; p=0.0016), chronic gastrointestinal tract disease (pr =1.60; p<0.0001), respiratory disease (pr =1.48; p<0.0001), haemoglobin immune disease (pr=1.50; p=0.0166), allergies (pr =1.80; p<0.0001), prescribed chronic medication use (pr= 1.14; p=0.0424) and history of use of analgesic/antiinflammatory medication use (pr =4.55; p<0.0001). conclusion: risk factors that should be considered when implementing prevention programs are age, race distance and male sex as well as years participation in endurance running events, medication use and a history and symptoms for chronic disease. future research must focus on these novel independent risk factors. key words: muscle strain injury, recreational running injuries, chronic disease, medication use, intrinsic risk factors 30 o24: injury surveillance in school rugby union in ireland therese m. leahy1, ian c. kenny1,2, mark j. campbell1,3 giles d. warrington1,2, roisin cahalan2,4, andrew j. harrison1, mark lyons1, liam g. glynn5, thomas m. comyns1,2 1 department of physical education and sport sciences, university of limerick, limerick, ireland 2 health research institute, university of limerick, limerick, ireland 3 lero, the irish software research centre, university of limerick, limerick, ireland 4 school of allied health, university of limerick, limerick, ireland 5 graduate entry medical school, university of limerick, limerick, ireland presenting author e-mail address: therese.leahy@ul.ie introduction: rugby union has increased in popularity among children and adolescents in recent years. school rugby in particular often represents a development pathway into elite academy and club rugby. rugby is a physically demanding sport and evaluating the injury risk in school players is paramount to player welfare and safety. injury risk within the school cohort remains unclear which is largely due to wide variations in study methodologies and surveillance practices. methods: the irish rugby injury surveillance (iris) project developed a rugby specific webbased surveillance system (irisweb). injury data were collected from 11 elite senior (senior cup) school teams across one season using the irisweb system. injury recorders inputted data for 305 male players aged 17-19 years for 95 matches (70mins duration). results: the overall match time-loss incidence rate was 67.8/1,000 player hours. the most common injuries were ankle ligament sprains (17%; 11.4/1,000 player hours), shoulder subluxations/dislocations (11%; 7.2/1,000 player hours) and concussion (10%; 6.6/1,000 player hours). the shoulder was the most commonly injured body location (26%; 17.4/1000 player hours). the majority of injuries occurred during the tackle event (56%), with more injuries resulting from tackling than being tackled. sprains were the most common injury type. in school rugby the blindside flanker suffered the most injuries (14%). most injuries occurred during the third quarter of the match. conclusion: the incidence rates reported here are higher than previously reported (leahy et al., 2019) for school rugby and adult amateur rugby (yeomans et al., 2018), however, are lower than those reported for the professional game (williams et al., 2013). compared to adult amateur rates and locations, schools can seek to protect younger players in target ways. when added to pooled data from future seasons of iris injury surveillance, this information aims to enhance the health and welfare of rugby union players across the irish school game and beyond by providing information on injury patterns that can impact on governing policy regarding injury prevention measures. references: leahy tm, kenny ic, campbell mj, warrington gd, cahalan r, harrison aj, lyons m, glynn lg, comyns tm. injury surveillance in school rugby: a systematic review of injury epidemiology & surveillance practices. physical therapy in sport. 2019;38:170-8. williams, s., trewartha, g., simon, k., et al. (2013). a meta-analysis of injuries in senior men's professional rugby union. sports medicine, 43(10), 1043e1055. yeomans, c., kenny, ian c., cahalan, r., warrington, g. d., harrison, a. j., hayes, k., et al. (2018). the incidence of injury in amateur male rugby union: a systematic review and meta-analysis. sports medicine, 48(4), 837e848. 31 o25: physical activity and risk factors for chronic non-communicable disease in relation to disease severity in patients with multiple sclerosis – a cross sectional survey desiree maartens1, wayne derman md phd1, susan hanekom pt phd2, martin heine phd1,2 1 institute of sports and exercise medicine, faculty of health and medicine, stellenbosch university, cape town, south africa. 2 department of physiotherapy, faculty of health and medicine, stellenbosch university, cape town, south africa presenting author e-mail address: ddmaartens@gmail.com introduction: due to the improved medical management of patients with ms (pwms) there has been an increased interest in secondary prevention of chronic comorbidity. it can be hypothesized that with increasing disease severity, pwms are less likely to engage in physically activity thereby are predisposed for factors for comorbidity and specifically chronic noncommunicable diseases of lifestyle. methods: the first ever national survey including outcomes on health status, physical activity, and societal participation of patients with ms in south africa was conducted through the national ms society. self-reported risk factors including body mass index (bmi; underweight, normal, overweight, obesity i iii), presence of high blood pressure and high cholesterol, were compared using descriptive statistics across levels of disability (patient determined disease steps [pdds]; mild, moderate, severe) and physical activity (international physical activity questionnaire [ipaq]; inactive, minimally-active, and health-enhancing active). results: 122 of 1 000 (12.2%) completed the survey (age=47.4±9.7yr, male (%) =14, disease duration=10.7±9.1yr). patients with moderate ms reported a significant (chi-square<.05) higher presence of high blood pressure (37%), and high cholesterol (37%) relative to patients with mild ms (12 and 14%). independent of disease severity, >68% of pwms were either overweight or obese. patients with severe ms reported the highest bmis (obese class i 27%, class ii 14% and class iii 9%). five percent of pwms are health-enhancing active, 31% minimally active and 64% inactive. there was a trend (p=.06) towards lower levels of physical activity in patients with moderate ms (inactive=77%, minimally-active=23%). conclusion: patients with ms are generally inactive independent of disease severity. the presence of self-reported risk factors significantly increased with disease severity, and are indicative of a higher risk for chronic non-communicable disease across the lifespan. 32 o26: influence of an exercise program on perceptions and knowledge of modifiable risk factors for non-communicable diseases sweetness j. makamu-beteck 1, sarah j. moss 1, lainie cameron 1,2, francois g. watson 3 1physical activity, sport and recreation, north-west university, potchefstroom, 2 school of health and wellbeing, university of southern queensland, 3numiq focus area, north-west university, potchefstroom presenting author e-mail address: sweetness.beteck@gmail.com background: health behaviours are embedded in knowledge, attitudes, and beliefs about illness and health. facilitators and barriers need to be understood to promote healthy behaviours. in this study, we explored the influence of an exercise intervention on the perception and knowledge of modifiable risk factors for non-communicable diseases among black women. methods: we used a convergent parallel mixed-method design. qualitative and quantitative data were collected at baseline (n=95), 12-weeks (n=55), and 24-weeks post-intervention (n=44) from black african females aged 28 to 78 years. heart disease and physical activity knowledge surveys were completed at these three time points. measures of modifiable risk factors for ncds, namely body fat percentage, body mass index, blood pressure, peripheral blood glucose, serum cholesterol, and objective physical activity for seven consecutive days, were collected. a subgroup of 25 women participated in focus group discussions exploring their knowledge and perceptions of modifiable risk factors for non-communicable diseases. participants received a progressive, supervised exercise intervention once per week for 60 minutes during the intervention of 24-weeks. results: the findings indicate that 12-weeks of exercise intervention significantly decrease the systolic blood pressure from 142 to 134 mmhg (p < 0.001); increased physical activity level from 1.4 to 1.6 (p<0.001), physical activity knowledge (8.8 to 9.4; p<0.001) and knowledge of heart disease (11 to 14; p<0.001). bmi decreased significantly from baseline (32 kg/m2) to 12weeks (31 kg/m2; p = 0.02) of intervention. physical activity level, physical activity knowledge, heart disease knowledge, sbp and bmi remained unchanged from 12to 24-weeks of exercise intervention. an adapted health belief model was used to interpret the qualitative findings. health exposures and cultural traditions influenced the perceptions of the participants. increased physical activity levels were driven by motivation from others and experiencing health improvements. conclusions: supervised exercise has shown to positively influence black african females’ healthy behaviours through a deeper understanding of cultural perceptions of modifiable risk factors for non-communicable diseases. structural knowledge of physical activity was not increased by the 24-week supervised exercise, although bp was significantly reduced. 33 o27: the batting backlift technique in cricket: what is the consensus at all skill levels? habib noorbhai1 1department of sport and movement studies, faculty of health sciences, university of johannesburg, johannesburg, south africa e-mail address: habibn@uj.ac.za introduction: the batting technique in cricket consists of various elements such as the grip, stance, backlift, downswing, impact with the ball and follow through. whilst there has been an extensive amount of research into these batting elements, there is not an adequate amount of research specifically on the backlift technique. we aimed to investigate and provide a scientific understanding of the batting backlift technique (bbt) in cricket at the various skill levels. aims: we aimed to investigate the bbt of the most successful batsmen (n = 65) in the last 120 years; players in the indian premier league (ipl) (n = 30); semi-professional, professional and international cricketers (n = 155) from south africa and the united kingdom; and coached and uncoached cricketers (uc) (n = 80). methods: biomechanical and video analyses were performed on all participant groups. classifiers were utilised to identify the batting backlift technique type (bbtt) employed by all batsmen. all statistics and wagon wheels (scoring areas of the batsmen on a cricket field) were sourced online. a pearson’s chi-squared test, student t-test and t-test were performed in this study. all analyses were performed using r (r core team, 2014) at a significance level of α = 0.05. results: it was found that successful batsmen over the last 120 years did not conform to the current cricket coaching method that advocates a straight batting backlift technique (sbbt). instead, 77% of successful batsmen and 90% of ipl batsmen employed a lateral batting backlift technique (lbbt) in which they lifted their bats in the direction of second slip or beyond with the bat face towards the off-side. using this technique, both the toe of the bat and face of the bat points directly towards the off-side (usually between slips and point). the number of players using the lbbt was significantly greater than those using the sbbt (χ2 = 19.2, df = 1, p 0.001). given these findings, we were curious to determine whether this finding was similar at other levels of cricket. it was found that a lbbt is more prevalent at the highest levels of the professional game and a likely contributor factor for successful batting at the highest level (p0.05). we then proceeded to investigate the bbt amongst the lower levels of cricket (junior and adolescent cricketers). it was found that more than 70% of uc adopted a lbbt, whereas more than 70% of coached cricketers adopted the sbbt. discussion and conclusions: the lbbt is a likely contributing factor to successful batsmanship at all levels of cricket ability (junior cricketers, adolescent cricketers, semi professional cricketers, professional cricketers, international cricketers and former elite/successful cricketers). early coaching emphasising the sbbt (one of the basic fundamentals of batting coaching) could be less favourable to the long-term success of young cricketers. coaching a lbbt to young batsman may be challenging and, therefore, a coaching cricket bat has been developed and has shown to be a promising training aid for coaching the lbbt to young cricketers. the findings and elements represented in this paper are not generalisable to both men and women’s cricket, and further research should be conducted to reach the consensus of the backlift in women’s cricket. 34 o28: ligament injuries occur in every match during the super rugby tournament (2013 2016) sibusiso ntuli1, a jansen van rensburg1, martin p. schwellnus1,2,3, dina c (christa) janse van rensburg1, charl janse van rensburg4, esme jordaan4,5 presenting author e-mail address: sbu.ghost@gmail.com 1 sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 2 international olympic committee (ioc) research centre, south africa 3 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa 4 biostatistics unit, medical research council, parow, south africa 5 statistics and population studies department, university of the western cape introduction: rugby union is a contact sport resulting in injuries, mostly to the soft tissues (muscle-tendon and ligaments). there are limited data on the incidence, specific anatomical area affected, severity and mechanisms of ligament injuries in rugby union. this study aimed to determine the incidence rate (all, match and training; specific anatomical area), overall severity and general mechanism of ligament injuries amongst elite rugby players. methods: a prospective observational study in 866 elite south african rugby players participating in the super rugby tournament (2013-2016). team physicians daily reported injuries sustained during match and training throughout the tournament (76301 player-hours, 6520 match player-hours, 69781 training player-hours). overall injury rates (ir per 1000 playerhours: 95%ci), ir by anatomical area, severity grade (% moderate/severe: >8 days lost), and mechanism (% contact vs. non-contact) of ligament injuries are reported. results: 257 ligament time-loss injuries were recorded (84.1% during matches, 15.9% during training) with an overall ir of 3.4 (3.0-3.8). ligament ir was significantly higher during matches (33.1; 28.9-37.9) vs. training (0.6; 0.4-0.8) (p<0.001). the ir of match ligament injuries was significantly higher in the lower limb (18.7; 15.5-22.3) vs. the upper limb (9.8; 7.6-12.5) (p<0.05). specific ligament ir, within main anatomical areas, was highest in the ankle (0.88; 0.68-1.12) and knee (0.86; 0.67-1.10), followed by the shoulder/clavicle (0.59; 0.43-0.79). a total of 44.8% ligament injuries were classified as moderate/severe (>8 days lost), and contact (80.8%) rather than non-contact (19.2%) (p<0.001) was the general mechanism of ligament injuries. conclusion: during the super rugby tournament, >1 ligament injury will occur in every match played by two teams. the most common ligament injuries occur in the lower limb (ankle and knee region) and shoulder/clavicle. in 45% of cases, the player will not be available for training/match for at least 8 days. this information can positively influence prevention programs. 35 o29: performance and anthropometrical differences between sexes at the onset of puberty charné scott 1, kirsty elliott 1,2, james clark 1,2, cassidy grobler 3, mariska fisher 3, charl janse van rensburg 4 1sport, exercise medicine and lifestyle institute (semli) and division of biokinetics and sports, 2science, department of physiology, faculty of health sciences, university of pretoria, 3department of sport and leisure studies, university of pretoria, 4biostatistics unit, south african medical research council presenting author e-mail address: charne.scott@semli.co.za introduction: understanding anthropometric and physical performance capability between youths of similar maturational status (pre-pubertal) but in different sexes, is needed to guide professionals in the prescription of exercise and sport. the aim of this study was to compare anthropometric and physical performance parameters in pre-pubertal (pre-peak height velocity; pre-phv) girls and boys. methods: 62 active youths (age = 11.7 ± 1.0 yrs.; females = 37, males = 25), were classified as pre-phv, according to maturity status (mirwald equation). anthropometric measures (height, weight, body fat percentage, arm span, leg length, seated height) and physical performance tests (grip strength, vertical jump, prone bridge, modified sit and reach) were compared between girls and boys with the same maturity status. results: chronological age and anthropometric measures (height, weight, absolute arm span, absolute and relative seated height and absolute and relative leg length) were significantly higher in boys compared to girls (p=0.05), but body fat percentage was not different between girls and boys. within the performance tests 1) boys scored significantly higher in absolute grip strength (r, p=0.00; l, p=0.00) absolute vertical jump height (p=0.008), and relative grip strength (kg/kg; mean ± sd)(left) (boys = 0.52 ± 0.12; girls = 0.45 ± 0.09; p=0.018), 2) girls scored significantly better than boys in absolute modified sit-and-reach test (p=0.05), and relative to stature (boys = 0.19 ± 0.03; girls = 0.24 ± 0.07; (cm/cm) p=0.01), and 3) there was no significant between-sex difference in relative vertical jump height (p=0.07) and absolute prone bridge time to exhaustion (p=0.29). conclusions: in absolute performance measures there were significant differences between prepubertal boys and girls, and therefore, prescription of exercise and sport should be tailored accordingly. 36 o30: there is a high rate of medical encounters (1 in 50 runners) during the 90km “comrades” ultra-distance race a safer study in 84 117 ultramarathon runners nicola sewry 1,2, jeremy boulter 3, martin schwellnus 1,2 1 sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa, 2 international olympic committee (ioc) research centre, south africa, 3 medical director, comrades marathon presenting author e-mail address: nicolasewry@hotmail.com introduction: the 90km “comrades” ultramarathon is a popular annual event but there are limited data on medical encounters during this race. the purpose of this study was to determine the incidence rate of medical encounters (both illness and injuries) over multiple years during the 90km “comrades” ultramarathon. methods: a retrospective clinical audit during the “comrades” ultramarathon (2014–2018) was conducted, and involved 84 117 race starters. medical encounter (mes) (moderate and serious life-threatening) data were collected over the years by medical doctors during and immediately after the event. data were retrospectively coded using the 2019 international consensus definitions for mes. incidence rate (ir: per 1000 race starters) for all mes, illness related mes, injury-related mes and organspecific illness-related mes were reported. results: the overall ir for mes over the five years was 21.0 (95%ci: 20.0–22.0) per 1000 starters (n=1 768). the ir for illness-related mes (20.2; 95%ci: 19.3–21.2) was significantly higher than injury-related mes (0.8; 95%ci: 0.6–1.0). the ir for serious life-threatening mes was 1.9 (95%ci: 1.6–2.2) (1 in 526 starters). the highest ir, by affected organ systems for illness-related mes, were: fluid and electrolyte (10.5; 95%ci: 9.8–11.2), central nervous system (4.0; 95%ci: 3.5–4.4), gastrointestinal (2.8; 95%ci: 2.4–3.1) and cardiovascular (1.2; 95%ci: 1.0–1.5). conclusions: the ir (per 1000 starters) of mes during the comrades marathon (21) is much higher compared to other endurance running events in south africa (ir=5 in 21.1km two oceans and ir=13 in 56km two oceans). risk factors associated with this high incidence require investigation so that interventions can be developed and implemented to improve safety of the participants’. 37 031: perceptions of training load and wellness monitoring of stellenbosch university high performance student-athletes sean surmon 1,2,3, lindsay starling 1,2, grant van velden 3, wayne derman 1,2, james c brown 1,2 1 institute of sport and exercise medicine, division of orthopaedics, department of surgical sciences, stellenbosch university, cape town, south africa 2 ioc research centre, south africa 3 maties sport, stellenbosch university, stellenbosch, south africa introduction: the effective monitoring of athletes can assist in optimising their performance. this monitoring is particularly important in university student-athletes who have academic stressors additional to their training. the stellenbosch university (maties) high performance programme manages the top student-athletes and have implemented a training load and wellness monitoring system to assist with this. the aim of this study was to investigate student-athletes’ perceptions of this monitoring system and identify potential barriers to their adherence to the programme. method: an internal survey was sent to all maties high performance athletes (n=156) across six sporting codes. four of this survey’s questions were based upon a study conducted in nine elite u.k. athletes and two additional questions were specific to the maties high performance context. results were presented as frequencies on the original likert scale. results: ninety-six % of athletes (n=149) answered this survey. half (50%, n=74) of all athletes agreed that they received sufficient feedback from the data that they entered. almost half (46%, n=69) agreed that sufficient action was taken by their strength and conditioning trainers when they indicated a meaningful change in their monitoring scores. almost all (97%, n=144) athletes agreed that they responded honestly to training monitoring questions. about two-thirds (67%, n=100) of athletes agreed that training monitoring and feedback helped to optimise their training performances. conclusion: overall, the maties high performance student-athletes were substantially more positive about training monitoring than the elite uk athletes. this positivity bodes well for the maties high performance programme, but also highlights the importance of regular feedback to these student-athletes. 38 o32: are training/running history, chronic diseases and medication use risk factors for injury prone runners? a safer study in 75 421 race entrants sonja swanevelder 1, nicola sewry 2,3, martin schwellnus 2,3,4, esme jordaan 1,5 1 biostatistics unit, south african medical research council, south africa, 2 sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa, 3 international olympic committee (ioc) research centre, south africa, 4 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa, 5 statistics and population studies department, university of the western cape presenting author e-mail address: sonja.swanevelder@mrc.ac.za introduction: chronic injuries are common in recreational runners, and often interfere with training and competition. the aim of this study was to investigate risk factors associated with being “injury prone” in entrants for a mass community-based running event. methods: data from an online pre-race medical screening questionnaire (75 421 consenting entrants) were analysed, using a cross-sectional observational study design. injury prone had 3 categories: 1) “none” (never injured) 2) “fairly” (less years injured than years entered), 3) “very” (always injured when entering). risk factor categories (demographic info, running/training history, history of existing chronic diseases and medication use) were explored for being a “low” injury prone (lip) runner by using an ordinal multinomial regression, reporting probabilities and odds ratios (or) (with 95% cis). significance was at the 5% level. results: females, younger runners, 21.1 km (compared to 56 km) runners and runners with a higher body mass index (bmi) were associated with being a lip runner. running/training history, chronic diseases and medication risk factors were adjusted for gender, race distance and age category. individual risk factors that were subsequently significantly associated (p<0.0001) with being a lip runner were:1) certain running/training history variables, 2) analgesic/antiinflammatory (aaim) medication use (or=0.24), gastrointestinal disease (or=0.39), symptoms for cardiovascular disease (cvd) (or=0.41), haematological/immune disease (or=0.47), nervous/psychiatric disease (or=0.48), allergies (or=0.49), respiratory disease (or=0.50), kidney/bladder disease (or=0.52), history of cvd (or=0.52), prescribed chronic medication use (or=0.56), risk factors for cvd (or=0.57), metabolic disease (or=0.65) and cancer (or=0.85). further analyses include a final multiple ordinal multinomial regression model. conclusions: the most significant risk factors for runners not to be a lip runner included aaim medication, gastrointestinal disease, symptoms of cvd and an immune disease. these and some of the other risk factors should be further investigated for specific chronic injuries. 39 o33: pacing characteristics of whole and part-game players in professional rugby union jason tee1,2 yoga coopoo3 and mike lambert4 1. department of sport studies, faculty of applied sciences, durban university of technology, south africa. 2. carnegie applied rugby research (carr) centre, institute for sport, physical activity and leisure, leeds beckett university, leeds, united kingdom. 3. department of sport and movement studies, faculty of health sciences, university of johannesburg, south africa. 4. division of exercise science and sports medicine, department of human biology, university of cape town, cape town, south africa. presenting author e-mail address: jasont@dut.ac.za introduction: contemporary theories on players’ intensity distribution in team sports suggest they regulate their outputs using pacing strategies. there is currently limited information on the effect of bout duration on pacing and movement patterns in rugby union match play. this study investigated the effect of different bout duration types (whole game, starter or finisher) on movement patterns of professional rugby union players within different position groups (forwards and backs). methods: global positioning system (gps) and accelerometer data were collected from 100 professional match participations to determine temporal effects on movement patterns. results: for forwards, finishers (players who entered the game as substitutes) demonstrated significantly greater high-speed running distance (% difference, ± 90%ci; magnitude based inference and effect size) (­ 55, ±17%; very likely large) and acceleration frequency (­ 78, ±59%; very likely large). backs demonstrated no significant bout effects, but starters (players who started the game and were later substituted) tended (p = 0.07) to display greater high speed running distance than whole game players (+27, ±21%; es = likely medium). forwards displayed “slow-positive” pacing strategies regardless of bout type, while backs displayed “flat” pacing strategies. conclusions: forwards and backs adopt different pacing strategies regardless of bout type, with forwards demonstrating progressively greater performance decrements over the course of the match. these findings reflect differing physical demands, notably contact and running loads, of players in different positions. 40 o34: effective working processes employed by a multidisciplinary team to reduce injury outcomes in a professional rugby league academy. jason tee1,2 and fieke rongen2 1. department of sport studies, faculty of applied sciences, durban university of technology, south africa. 2. carnegie applied rugby research (carr) centre, institute for sport, physical activity and leisure, leeds beckett university, leeds, united kingdom. presenting author e-mail address: jasont@dut.ac.za introduction: in professional team sport managing injury risk depends on the effective collaboration of technical/tactical coaches, strength and conditioning coaches, sports medicine practitioners and sport scientists within a multidisciplinary team (mdt), yet to date no research has examined how these professionals might co-ordinate their efforts. the aim of this research is to examine the processes and interactions utilized by a demonstrably effective mdt. methods: this research utilised a mixed methods design incorporating both quantitative and qualitative research methods. the efficacy of the mdt was established by quantifying the injury burden of the team across two seasons. semi-structured interviews were conducted with all mdt members at the end of the second season, to determine each individual’s role within the injury prevention process and how these were co-ordinated between disciplines. interviews were thematically analysed to provide insight into the approach adopted by the mdt. results: the mdt achieved a 41% reduction in team injury burden during the second season in question (first season 3 450 vs. second season 1428 days/1 000 hours). thematic analysis identified three key constructs that contributed to the mdt’s success; 1) shared values, 2) expertise and 3) the effective operationalization of underpinning values and expertise. shared values expressed by the mdt members included doing what is best for players, rather than for the team, and shared responsibility for injury prevention. all mdt members were experts in their own fields but identified that they had to learn how to be effective within the environment and required skill in building interpersonal relationships. the operationalisation of these principals took place through iterative plan-do-review cycles underpinned by sophisticated data collection and monitoring and the provision of time and resource to complete these operations. conclusion: this research offers insights into “how” effective mdt’s work to achieve injury reduction, and the models and processes presented will inform practice for other mdt’s working in sport. 41 o35: profile of participants in the 19th world transplant games johan van heerden, nicole forman, hayley freimond, sinothando mbanjwa department of biokinetics, exercise and leisure science, university of kwazulu-natal, south africa presenting author e-mail address: vanheerdenj@ukzn.ac.za introduction: the world transplant games (wtg) started in 1978 and are run every two years but research related to the event is limited. accordingly, the purpose of this study was to analyse the profile of participants in the 19th world transplant games held in durban, south africa. methods: the design comprised a questionnaire survey among participants (males and females) participating in the wtg. statistical analysis included chi-square analysis and t-tests to distinguish statistical differences between sub-sets of responses with alpha set at p<0.05. results: the mean age of respondents (n=60) was 39.51± 13.59 years with most falling into the category of 18-29 years (32.8%) and 50-59 years (29.5%) with the majority (p<0.05) being male (74%) compared to female (26%). the most common organ received (p<0.05), was a kidney (51.50%) followed by the heart (15.20%) and the liver (10.60%). the organ was generally received within the first 5 years of requiring a transplant (32.8%) and in most cases the time waited to receive the organ ranged between 0-6 months (35.1%) and between 7-24 months (35.1%). the majority (p<0.05) returned to physical activity within 6 months of receiving the organ (71%) and had been physically active for 9 years or more (73%; p<0.05). the majority (68%; p<0.05) were participating in the games for the third time or more and the activity most commonly participated in was athletics (31.10%) followed by swimming (24.40%) and racquet sports (22.2%). participants rated (scored out of 10) their mean health condition better (p<0.05) after transplant (8.3 ± 1.9) than before (4.6 ± 2.9) as well as their physical ability being greater (p<0.05) after transplant (8.2 ± 1.5) than before (4.9 ± 3.0). conclusions: this study found that organ transplant improved participant’s perceived health and physical ability and demonstrates that organ transplant recipients can be rehabilitated successfully to lead normal lives and compete athletically. 42 o36: presenting features of female collegiate sports related concussion: a descriptive analysis r. van tonder1,3, l. kunorozva1,3, p. l. viviers1,2,3, j.c. brown1,3 and e. w. derman1,3 1institute of sport and exercise medicine, division of orthopaedics, faculty of health sciences, stellenbosch university, stellenbosch, south africa 2campus health service, stellenbosch university, stellenbosch, south africa 3ioc research centre, south africa background: concussion is increasingly being recognised as an important sports related injury, especially in collision and contact sports. it constitutes a public health concern, given the large population at risk. the injury burden associated with concussion is high. evidence suggests that females are at increased risk for src and have higher symptom burden before and after injury. aims: the purpose of this study was to describe presenting features of female sports related concussion (src) at a collegiate campus-based health service. methods: a retrospective cohort analysis of females presenting with src during the period 2012 – 2018 was performed. concussion evaluation included the use of the sports concussion assessment tool (scat) versions 3 and / or 5. the scat questionnaire is focused inter alia on the self-reporting of symptom severity based on a scale of 0 – 6, where 0 indicates the absence of a symptom and 6 indicates the highest severity. there are 22 symptoms with a maximum possible severity score of 132. results: 43 (29%) females with src were identified, with a mean age of 23.2 (mean ± sd; 23.2 ± 3.1). field hockey accounted for the largest number of srcs, (21; 49%). the 3 most frequently reported symptoms were headache (85%), feeling slowed down (83%) and pressure in head (83%). the 3 symptoms with highest average severity score were headache (2.95), feeling slowed down (2.93) and fatigue / low energy (2.88). a history of prior concussion (n = 13) or anxiety and / or depression (n = 8) lead to higher average total severity scores of 51 (vs 39.8) and 62.9 (vs 38.6) respectively. conclusion: symptoms with the highest burden were headache and feeling slowed down. the average total symptom severity score appears to be higher in those with at least 1 previous concussion or a history of anxiety and / or depression. 43 o37: the relationship between physical activity and left carotid intima-media thickness among educators in south africa: the sabpa study tamrin veldsman1 (m.sc.), mariette swanepoel1 (ph.d), andries monyeki1 (ph.d), sanette brits2 (ph.d), leoné malan2 (ph.d) 1physical activity, sport and recreation research focus area (phasrec), faculty of health sciences, north-west university, potchefstroom, south africa 2hypertension in africa research team (hart), school for physiology, nutrition and consumer sciences, north-west university (potchefstroom campus) presenting author e-mail address: tamrin.veldsman@nwu.ac.za introduction: obesity and physical inactivity are associated with cardiovascular disease (cvd). the relationship between objectively measured physical activity (pa) and left carotid intimamedia thickness (l-cimt) (carotid atherosclerosis marker) has sparsely been investigated. the aim of the study was to determine the relationship between pa status and l-cimt among educators in south africa. methods: the cross-sectional study design was done on 216 urban-dwelling south african educators (x̅ 49.67±8.44 years) from the sympathetic activity and ambulatory blood pressure in africans (sabpa) cohort study. a sonosite micromaxx ultrasound system measured l-cimt and actiheart determined consecutive seven days pa. data were analysed by means of descriptive statistics, independent t-tests, chi-square and one way anova. the relationship between activity energy expenditure (aee) and l-cimt according to pa categories was analysed using a spearman and partial correlations. results: more than a third of the participants were overweight and obese, and being more pronounced in the sedentary and light activity pa groups. middle adulthood, showed a significantly higher mean (0.73±0.14 mm) (p>0.001) l-cimt compared to young adulthood (0.64±0.16 mm). aee was negatively associated with l-cimt in the light intensity pa group (r=-0.02; p=0.84). a significant positive relationship was found between aee and l-cimt (r=0.69; p=0.001) in the moderate to high pa group. when partial correlation was calculated between aee and l-cimt (controlled for age, body mass index and waist circumference), respective significant positive relationships (r =0.48, p=0.05; r=0.99, p=0.001; r=0.53, p=0.02) in the overweight and obese middle adult age group, were observed. conclusions: participation in light intensity pa may be effective in the reduction of l-cimt. the observed prevalence of overweight and obesity might have contributed to the positive relationship between aee and l-cimt. given the health implication of these findings to cvd, urgent strategic physical activity intervention studies are recommended to improve the situation. 44 o38: health promotion in individuals with spinal cord injuries: what is standing in the way of enhancing physical activity? candace vermaak1, suzanne ferreira2, elmarie terblanche1 1department of sport science, faculty of medicine and health sciences, stellenbosch university. 2institute of sport and exercise medicine, faculty of medicine and health sciences, stellenbosch university presenting author e-mail address: candacev@sun.ac.za introduction: barriers to physical activity are universal, however, in a developing country and in individuals with a spinal cord injury (iwsci) these barriers are often exacerbated and multiple. whereas, facilitators are crucial in promoting and sustaining physical activity (pa) behaviour. thus, the aim of the study was to determine the barriers and facilitators to pa for iwsci within the cape metropole. method: a mixed-method research design was used. a self-developed questionnaire was used to gather the information regarding the barriers and facilitators to pa. the barriers and facilitators were themed according to the theory of planned behaviour into personal, social, environmental and program/policy. fifty seven iwsci (men: n =49; women: n = 8) completed the questionnaire. results: environmental barriers were most prevalent (40%) and included limited facilities and transport, as well as difficulties related to the weather. program barriers (33%) included lack of trained volunteers and appropriate programs, while personal barriers (20%) included injury level and secondary conditions. the social barriers accounted for 7% and included lack of information received from therapists regarding physical activity. the facilitators identified included enjoyment, a desire to be physically active (personal 44%), family support, support from peers with disabilities (social 26%), accessibility and the facility being a safe location (environmental 17%), skilled staff and better quality programs (program/policy 13%). conclusion: it is evident that iwsci face various obstacles in being physically active, which ultimately obstructs the journey to health and wellness. if health and wellness is not achieved, quality of life is affected and it can lead to many other co-morbidities and even early mortality. the findings demonstrates the importance of identifying and the removal of such barriers to promote and foster effective interventions for an active and healthy lifestyle for iwsci. 45 o39: acute injury medical encounters (mes) are 3.9 times more common than illness mes in mass community-based trail running events: safer study in 2428 race starters carel viljoen1, nicola sewry2,3, martin schwellnus3,4,5, dina c (christa) janse van rensburg4, sonja swanevelder6, esme jordaan6,7 1 sport, exercise medicine and lifestyle institute (semli) and department of physiotherapy, faculty of health sciences, university of pretoria, south africa 2 sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa 3 international olympic committee (ioc) research centre, south africa 4 sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, south africa 5 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa 6 biostatistics unit, south african medical research council 7 statistics and population studies department, university of the western cape, south africa presenting author e-mail address: carel.viljoen@up.ac.za introduction: trail running is characterized by “off-road” running on uneven and varying running surfaces perhaps predisposing runners to more acute injuries during races compared with road running. the aim of this study was to describe the epidemiology of race-day injury-related vs. illness-related medical encounters (mes) during a mass community-based trail running event over 3 years. methods: in this retrospective clinical audit in 2428 race starters during the 2012-2014 two oceans trail runs (10km and 22km), injury-and illness-related mes, defined as at least of moderate severity (2019 consensus statement), were recorded by race medical staff. crude incidence rate (ir per 1000 starters; 95%ci’s) of mes (all, injury-related and illness-related) and the ir of specific injuries (anatomical region) and illnesses (organ systems affected) were reported. results: 44 mes were reported in 2428 race starters with an overall ir of 18.1 (12.8-23.5). the ir for all injury-related mes was significantly higher than all illness-related mes [14.4 (9.619.2) vs. 3.7 (95%ci;1.3-6.1)]. the highest injury-related ir (ir;95%ci) in specific anatomical regions was the knee (4.5;1.9-7.2), followed by the ankle (2.1;0.3-3.9). lacerations/abrasions (ir=8.2,95%ci;4.6-11.8), and ligament sprains (ir=2.1;0.3-3.9) were the most common tissue type injured. all ligament sprains were in the ankle. exercise associated postural hypotension (ir=1.6;0.0-3.3) was the most common illness-related me. conclusion: at the two oceans trail running races, acute injury-related medical encounters (mes) are 3.9 times more common than illness-related mes. in addition, the ir of overall mes in the trail running races are higher than in the 21.1km (ir=5.1) and 56km (ir=13.0) road running events. finally, there is a particularly high ir of acute ankle ligament sprains in trail running. these findings are important for trail running race organizers and supporting medical teams to prepare for race day, and to develop prevention programs for mes. 46 o40: over 14% trail runners report an overuse injury in a 12-month period, mostly affecting the knee and anterior thigh: a safer study in 2824 race entrants carel viljoen1, nicola sewry2,3, martin schwellnus3,4,5, dina c (christa) janse van rensburg4, sonja swanevelder6, esme jordaan6,7 1 sport, exercise medicine and lifestyle institute (semli) and department of physiotherapy, faculty of health sciences, university of pretoria, south africa 2 sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa 3 international olympic committee (ioc) research centre, south africa 4 sport, exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, south africa 5 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa 6 biostatistics unit, south african medical research council 7 statistics and population studies department, university of the western cape, south afria presenting author email address: carel.viljoen@up.ac.za introduction: trail running differs from road running because of uneven and varying running surfaces, larger changes in altitude and large elevation gains/losses. injury patterns in trail running may differ from road running, but this has not been well studied. the aim was to determine the epidemiology (annual incidence) and nature of self-reported overuse/chronic injuries among trail runners (10km and 22km) participating in a mass community-based trail running events over a 4-year period. methods: a retrospective descriptive cross-sectional study was performed using data collected from a pre-race medical screening questionnaire completed by 2824 consenting entrants (79.6% of all participants) during the 10km and 22km two oceans trail runs (2012-2015). selfreported injury history, in the previous 12 months included data on anatomical site, tissue type, specific diagnosis and injury severity grade. main outcome variables were retrospective annual incidence (%runners:95% ci) and frequency (%) of injury characteristics by anatomical site, tissue type, specific running injury, and injury severity grade (1-4). results: 406 injuries in total were reported (12 participants reporting 2 injuries) with a retrospective annual incidence of 14.4% (95% ci;13.0–15.8). most commonly injured anatomical site were the knee (25.2%), anterior thigh (10.0%), shin/lower leg (8.4%) and ankle (8.4%). common injuries by tissue type were muscle (30.3%) and tendon (28.9%). the most common specific running injuries were iliotibial band syndrome (itbs) (20.0%), achilles tendon (8.6%) and hamstring injuries (7.9%). over 50% of the injuries were of grades 3 and 4 severity. conclusion: 14.4% trail runners report an injury in a 12-month period, most commonly affecting the knee and anterior thigh. over 50% of injuries were severe enough to affect training or racing. risk factors associated with injuries in trail runners need to be determined, in order to design and implement prevention strategies. 47 o41: exercise associated muscle cramp (eamc) is almost twice as common among 21.1km compared to 56km runners – a safer study in 76654 runners izaan de jager, bphys,1, martin schwellnus, mbbch, msc, md,2,3,4, carel viljoen, msc,1, elzette korkie, phd,1, sonja swanevelder, msc,5, esme jordaan, msc,5,6 1 sport, exercise medicine and lifestyle institute (semli) and department of physiotherapy, faculty of health sciences, university of pretoria, south africa 2 sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa 3 international olympic committee (ioc) research centre, south africa 4 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa 5 biostatistics unit, south african medical research council 6 statistics and population studies department, university of the western cape, south africa presenting author e-mail address: carel.viljoen@up.ac.za introduction: exercise associated muscle cramps (eamc) among distance runners has not been well studied. therefore, this study aimed to describe the epidemiology, clinical characteristics and severity of eamc in distance runners, and compare these characteristics between the 21.1km and 56km runners. methods: 76654 consenting runners completed an online pre-race medical screening questionnaire as part of the 2012-2015 two oceans race entry process (21.1km=47069; 56km=29585). the main outcome variables (adjusted for age and gender) are: lifetime prevalence, clinical characteristics (main muscle groups affected, timing of occurrence during a race, eamc severity, complex forms of eamc, and treatment of eamc) in all runners and sub-groups (21.1km vs. 56km) (%; 95%ci). results: the lifetime prevalence of eamc of all runners was 12.8% (12.6-13.1), and this was significantly higher in 21.1km (16.0%; 15.5-16.5) vs. 56km runners (8.8%; 8.5-9.1) (p=0.0001). the main anatomical regions affected by eamc in all entrants and in 21.1km and 56km runners were the calf (all=53.1%; 52.1-54.2), hamstrings (all=20.9%; 20.0-21.7) and quadriceps muscles (all=16.3%; 15.5-17.1). the majority of eamc occurred in the fourth quarter of a race (all=46.4%; 45.4-47.5, 56km=35.1%; 33.6-36.6, 21.1km=47.2%; 45.6-48.9) followed by after the race (all=22.3%; 21.4-23.2, 56km = 29.5%; 28.1-31.1: 21.1km = 18.6%; 17.5-19.8). the severity of eamc was classified by all runners as mild (65.2%; 64.2-66.2) followed by moderate (29.9%; 29.0-30.9). complex severe eamc (6.3%; 5.8-6.8), whole body cramping eamc (3.7%; 3.4-4.2) and eamc associated with dark urine (2.6%; 2.3-3.0) were reported. all runners indicated that stretching relieved an acute cramp most successfully (70.2%; 69.2-71.1), followed by rest (37.9%; 36.9-38.9) and massage (37.9%; 37.0-39.0). conclusion: about 12.8% of recreational runners report ever suffering from eamc and this was significantly higher in 21.1km sub-group (16.0%), compared to 56km runners (8.8%). most eamc in distance runners occurs in the calf and thigh muscles, presenting later 4th quarter and post-race. 48 o42: a history of multiple chronic diseases is associated with achilles tendon injuries in runners: a cross-sectional safer study in 76654 runners jonah young 1, martin schwellnus 2,3,4, kim nolte 1, sonja swanevelder 5, esme jordaan,5,6 paola wood 1 1 sport, exercise medicine and lifestyle institute (semli) and division of biokinetics and sports science, department of physiology, faculty of health sciences, university of pretoria, south africa 2 sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa 3 international olympic committee (ioc) research centre, south africa 4 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa 5 biostatistics unit, south african medical research council 6 statistics and population studies department, university of the western cape presenting author e-mail address: jonahyoung94@gmail.com purpose: achilles tendon injuries (ati) in runners is associated with multiple risk factors, with recent data showing a possible association between ati and chronic metabolic disease. the aim of this study was to determine whether chronic disease, in addition to previously reported risk factors, is associated with ati in the two oceans marathon runners (2012-2015). methods: online pre-race medical screening questionnaire data from 76654 consenting race entrants (71.8% of all entrants) were analysed, using a cross-sectional observational study design. a total of 739 (1.2%) entrants reported an ati. the following categories of risk factors associated with ati were explored using multi-variate analyses, reporting prevalence ratios (pr): race distance (21.1 km vs. 56 km), runner demographics, training/racing history, history of existing chronic disease, and medication use. results: when comparing race entrants who reported an ati to those who did not older age (>31yrs)(p<0.0001), male sex (pr=1.76; p<0.0001), and longer race distance (56km vs. 21.1km)(pr=2.06; p<0.0001) were associated with a higher prevalence of ati. independent risk factors associated with ati (adjusted pr for race distance, sex and age) were: increased years of recreational running (p<0.0001), risk factors for cardiovascular disease (cvd) (pr =1.77; p<0.0001), history of chronic gastrointestinal tract (git) disease (pr =2.06; p=0.0155), respiratory disease (pr =1.66; p<0.0001), nervous system/psychiatric disease (pr =1.56; p<0.0001), allergies (pr =1.89; p<0.0001) and history of use of analgesic/anti-inflammatory medication use (pr =4.83; p<0.0001). conclusion: the main findings of this study apart from age, race distance and male sex are that novel independent risk factors associated with ati include years of being a recreational runner, risk factors for cvd, history of respiratory or git or nervous system/psychiatric disease, allergy and analgesic/anti-inflammatory medication. these should be considered when implementing prevention programs and planning effective race medical support systems whilst future studies should focus on a establishing a causal relationship. key words: achilles tendon, overuse running injuries, chronic disease, medication use, intrinsic risk factors 49 clinical case presentations c01: sudden onset lateral foot pain in a tri-athlete emmari carstens (bsc physiotherapy), susan crumpton (bsc (med)(hons) exercise science (biokinetics), mba),dr pl viviers (mbchb, mmedsc, msc sport med, facsm) 1. institute of sport and exercise medicine, stellenbosch university, south africa 2. ioc research centre, cape town, south africa 3. campus health services, stellenbosch university, south africa history: a healthy 22-year-old male presented to the sports clinic complaining of lateral left sided foot pain. he was in training for a half iron-man event and had countless failed attempts at conservative management over the past 4 months. the pain started gradually within 2 running sessions with no clear mechanism of injury. initially he consulted his family physician who suspected a stress fracture and referred him for x-rays, which came back clear. he was management non-weightbearing in a moonboot for 3 weeks. after 3 weeks, he was still symptomatic and consulted a foot and ankle specialist. his findings were tenderness of the peroneus longus tendon and groove. he was referred for a mri that also came back clear. his advice was to see a biokineticist for rehabilitation. static and dynamic loading patterns were done by a podiatrist thereafter, who found cavo-varus feet and calcaneus hypermobility. he advised orthotics to help with load distribution. he continued managing his foot with orthotics and rehabilitation, which focused on improving foot contact and loading during running and general hip muscle recruitment. after 4 weeks of rehabilitation, he started with gradual return to running and again experienced pain after 1km. he presented to the sports clinic, were findings were no swelling or bruising, hypomobility of sij with hip movements on the left and severe gluteus medius spasm. the hypothesis was a glut medius triggerpoint referring laterally into the foot and he was referred to physiotherapy. previous relevant history includes episodes of recurring itb syndrome in the past 3 years and one episode of patella tendinopathy and patella femoral pain syndrome, all on the left side. normal medical and family history and didn’t use any medication to manage his symptoms. physical findings:generally healthy and active individual with presentation at the physiotherapy clinic, he had no pain with any functional testing of the lower limb and was able to jog and sprint pain free for about 50m. with hip flexion in standing, the sij on the left was not moving inferiorly. with palpation of the lumbar area he had tightness of quadratus lumborum and stiffness of levels l3-s1 centrally and unilaterally to the spine, left more than right. at the foot, had tenderness of the plantar fascia and hypermobility of the calcaneus on the left compared to the right. he also had mid-foot stiffness, specifically with pronation and inversion of the forefoot compared to the right. differential diagnosis:functional foot pain due to loading on the lateral part of the foot • biomechanical discrepency secondary to soft tissue tightness • midfoot joint stiffness which doesn’t allow for normal biomechanical movement when running hypothesis: biomechanical discrepancy due to soft tissue tightness of the gluteus medius and foot immobility leading to increased load on the lateral side of the foot. management : • specific soft tissue mobilisations of the quadratus lumborum and gluteus medius • mobilisation of the lower back t12-s1 centrally and unilaterally 50 • dry needling of the gluteus medius • midfoot and forefoot mobilisation • strapping to support calcaneus during running outcome: after 2 physiotherapy sessions, patient was able to run more then 2km painfree and after the 3rd session, was able to complete the half iron man 21 km symptom free. he returned to previous level of activity after his 3rd session. 51 c02: a multistructural knee injury in a female field hockey player tanya green (bsc physiotherapy) 1, 2, 3; susan crumpton bsc med hons exercise science (biokinetics) 1. 2, mba; dr pl viviers (mbchb, mmedsc, msc sport med, facsm) 1, 2, 3; prof wayne derman mbchb bsc (med) (hons), phd, ffims 1, 2 1institute of sport and exercise medicine, stellenbosch university, cape town, south africa 2ioc research centre, cape town, south africa 3campus health services, stellenbosch university, cape town, south africa history:a 20-year-old female field hockey player presented with a painful knee post sustaining a multistructural acute right knee injury after colliding with an opposition. the mechanism was a twist with hyperextension, no pop or tearing sound reported. she experienced immediate pain and was unable to bear weight, which forced her to discontinue playing. immediate fieldside management included ice, compression and immobilisation. the tournament physician examined her and made the diagnosis of lateral collateral ligament sprain (lcl) with lateral posterior meniscus injury, and referred her for further investigation when she returns home. on the first day after injury, the injured knee was swollen, painful and she was unable to straighten the leg. upon returning home a sports physician was consulted who requested an mri investigation and orthopaedic surgeon’s opinion. the clinical findings of the orthopaedics’ examination noted a small effusion, limited range of motion and tested positive for partial posterior collateral ligament (pcl) instability. the mri confirmed a partial thickness tear of the pcl, bone contusion or impaction fracture of the anterolateral tibial condyles, associated meniscal contusion or flap tear of the anterior horn of the lateral meniscus. conservative management was opted, which included immobilization in a brace and referred for physiotherapy. medical and family history were normal and the athlete was not on chronic medication or using any supplements. previous sport related injuries includes right hamstring strain (june 2017), concussion (august 2017) and left sided lumbar-sacral back pain (earlier in the year) which all resolved. physical findings:generally healthy and physically active female field hockey player. initially presenting at the physiotherapy clinic partial weight bearing (pwb) on crutches and immobilised in a pcl brace limited to 90° of knee flexion, with a moderate effusion. her passive range of motion was limited to 0-80° at this point she experienced pain and stiffness with both movements. pain ranging from 5-8/10 at worst on numeric pain rating scale (nprs). quadriceps lag of -15° due to stiffness and pain inhibition. pain and tenderness on palpation anterolateral over the lateral joint line, distal insertion itb and anterior knee soft tissue structures (due to the effusion), overall tightness of quadriceps and hamstrings. differential diagnosis/ hypothesis:lateral collateral ligament injury; anterior cruciate ligament injury; posterior cruciate ligament injury; lateral meniscus injury/ contusion; posterior lateral corner injury, bone contusion of femoral or tibial condyles, and associated lateral and posterior soft tissue injuries. final/ working diagnosis: partial pcl tear, bone contusion of anterolateral tibial condyle with a small impaction fracture and contusion of the anterior horn of the lateral meniscus. management and treatment outcomes:immobilization partial weight bearing on crutches and in pcl brace for 4 weeks guided by orthopaedic surgeon only to mobilise for knee flexion up to 90° with anterior tibial translation at all times 52 • physical therapy: manual therapy including soft tissue and joint mobilisation, electrotherapy modalities, taping, activation and strengthening of vastus medialis oblique, quadriceps and gluteal complex. • gradual mobilisation to full weight bearing • currently busy with rehabilitation under supervision of a biokineticist, focussing on sport-specific strengthening and proprioceptive training • aim to full integration to training and return to sport after 4 months 53 c03: an unexpected cause of leg pain in a 42 year old endurance runner melissa janse van vuren institute of sport and exercise medicine, stellenbosch university, south africa, ioc research centre south africa presenting author email address: jvvuren.m@gmail.com history: a 42 year-old long-distance runner presented to the sports medicine clinic two weeks after having successfully completed the two oceans marathon complaining of left calf pain. the onset of the pain occurred the day after the ultra-marathon but within a short period the pain was present after walking short distances. the pain was claudicant in nature with accompanying foot paraesthesia and leg weakness. rest pain was absent. other than a history of treatment naive hypercholesterolaemia and previous kidney stones, the patient was fit, and well, a non-smoker with some symptoms of atopy but no other symptoms of claudication or angina. there was no other relevant medical or family history. physical examination: • a normal general examination and vital signs. • there was no obvious swelling, discoloration or evidence of tissue loss of the lower limbs. • the left limb was slightly cooler to touch with a prolonged capillary refill time. • further examination of his pulses, his upper limb pulses were symmetrical and equal but on examination of his lower limbs his left femoral pulse was slightly diminished, with a soft bruit. the left popliteal and dorsalis pedis pulses were absent. • he was unable to run, with a claudication distance of 100 meter. • no left foot pulses felt post exercise or heard on office doppler examination. differential results: clinical evaluation strongly indicated a vascular cause of this presentation and the patient was urgently referred to a vascular surgeon for further evaluation. 1. clotting factor pathology 2. arterial dissection 3. atherosclerotic disease 4. vasculitis test results: duplex doppler was performed but slightly obscured by bowel gas, yet aorta and proximal common iliac seemed to be patent. the distal common iliac and proximal external iliac could not be visualized, but the distal external iliac and common femoral vessels were patent with biphasic flow. angiogram performed of the external iliac artery, demonstrated a string-like appearance pathognomonic of fibromuscular dysplasia. a full visceral angiogram revealed no involvement of the visceral vessels. the distal angiogram was normal. working diagnosis: fibromuscular dysplasia of the external iliac artery treatment and outcomes: 1. arteriotomy and thrombectomy was performed on the superficial femoral artery and the long saphenous vein was harvested and used as a venous patch. 2. 4 hours post-op review revealed a well perfused limb with good dorsalis pedis pulse. the patient was placed on xarelto for anticoagulation. 3. the patient was treated with initial rest with gentle mobilization and attention to maintaining range of motion. 4. a return to sport programme was then successfully instituted. 54 c04: persistent pain following ankle sprain: an unusual presentation of an osteoid osteoma dr wm sadie & prof ew derman institute of sport and exercise medicine, stellenbosch university, south africa; ioc research centre, south africa presenting author e-mail address: 11167688@sun.ac.za history: a 19-year-old female hockey athlete presented with an 18-month history of right sided ankle pain following a suspected ankle sprain whilst playing hockey. she was referred to the clinic by a physiotherapist who noted lateral ankle swelling and pain out of relation to the injury. furthermore, she was not responding to physiotherapy treatment. she had also been to consult an orthopaedic surgeon who had assessed her ankle as having a peroneus brevis tendinopathy, and an anomalous insertion of the peroneus tendon. these abnormalities had been reported at point of care ultrasound scanning. this condition was managed by corticosteroid injection which temporarily relieved the pain. after the pain returned a high volume injection was given in the painful area without any effect. further specific history, general medical and surgical history was not contributory; except for night pain, and response of pain to nsaids, which she had been ingesting for the previous year. previous orthopaedic history revealed some previous lower back pain relieved by physiotherapy. physical examination:physical examination revealed some discomfort of the right ankle when bearing weight and jumping. there was visible swelling over the medial malleolus. range of motion was normal. there was extreme tenderness of the lateral malleolus and pitting oedema present on palpation. differential diagnosis:complicated ankle sprain with missed fracture fracture with mal/non-union, or bone stress injury occult osteochondral lesion peroneus tendon injury complex regional pain syndrome osteoid osteoma special investigations:blood labs – within normal range x-ray of the ankle revealed cortical thickening with irregular margins of the distal fibular and associated soft tissue swelling. no nidus was identified on x-ray. mri routine sagittal, axial and coronal studies with additional fat saturation sequences. 1.5 tesla body scanner and ct scan were performed. these investigations revealed extensive bone marrow edema of the distal fibula with associated nidus. there was also significant surrounding sclerosis as well as periosteal new bone formation seen with extensive surrounding soft tissue edema. the features were compatible with an osteoid osteoma. final diagnosis: osteoid osteoma of the right distal fibula. treatment and outcomes:the patient was referred for radio-ablation which was successfully performed and a return to sport programme followed. the patient continues to recover well. osteoid osteoma is a rare cause of ankle pain. the purpose of this case study is to highlight to healthcare providers to be aware of rare causes of chronic persistent pain in the athlete who does not respond to the expected course of recovery. 55 c05: case report: a complicated shoulder dislocation in a collegiate rugby player dr craig thompson1,2,3 (mbchb, mphil sports med, uct); dr pl viviers1,2,3 (mbchb, mmedsc, msc sport med, facsm); prof wayne derman1,2,3 (mbchb, bsc (med)(hons), phd, facsm, ffims. 1. campus health service, stellenbosch university, cape town, south africa 2. institute of sport and exercise medicine, stellenbosch university, cape town, south africa 3. ioc research centre, cape town, south africa. history: a 23-year-old male collegiate rugby player injured his left shoulder whilst playing in a rugby union match. he was tackled and landed on the pitch on an overstretched left arm (shoulder abducted and flexed at point of contact with the pitch), whilst carrying the ball at speed. he had had no history of previous shoulder injuries. physical examination: clinical signs with the on-field medical assessment showed that the player supported his left arm in an abducted and a forward flexed position. an empty defect was palpable below the left acromion and the humeral head was palpable in the left anterior axillary area. neurovascular status in the left arm was intact. the player was removed permanently from the field of play. evaluation in the medical room by the match day doctor confirmed an anterior left glenohumeral dislocation, which was relocated without effort. post-reduction neuro-vascular status of the injured limb remained intact. whilst in the medical room, a spontaneous recurring left shoulder dislocation occurred, which was again reduced without effort and with no change in the limb neurovascular status post-reduction. differential diagnoses: 1. isolated anterior glenohumeral dislocation 2. humeral or clavicular fracture, with shoulder dislocation 3. rotator cuff or other ligamentous injury, with shoulder dislocation 4. bony bankart lesion, with shoulder dislocation 5. hill-sachs lesion, with shoulder dislocation. test results: x-ray (left shoulder): successful reduction of humeral head. no other bony abnormalities (including hill-sachs or bony bankart lesions) could be demonstrated. non-specific mineralization was noted in relation to the supraspinatus tendon, a possible avulsion fracture. no humeral fractures were noted. mri (left shoulder): humeral avulsion of the gleno-humeral ligament (hagl injury), with retraction was demonstrated. full-thickness tear of supraspinatus tendon, with minimal retraction. articular surface tear of subscapularis tendon. gleno-humeral joint effusion. slap lesion (biceps anchor). muscle oedema (subscapularis and infraspinatus muscles) working diagnosis: acute antero-inferior left shoulder dislocation, complicated by hagl lesion and multiple rotator cuff tears. treatment and outcomes: 56 1. referral – orthopaedic surgeon for surgical management through an open procedure. 2. post-operative physiotherapy rehabilitation: • mobilization and range of motion complete mobility achieved after 14 weeks • strengthening commenced after full mobility 3. final outcome – the athlete is still busy with a shoulder strengthening rehabilitation program. he remains asymptomatic and functional but does not yet meet criteria for return-to-play. 57 poster presentations p01: an investigation of the knowledge of south african high school rugby coaches on concussion and the return to play protocol nc abel, cc grant, dc janse van rensburg. section sport medicine, faculty of health sciences, university of pretoria, south africa, presenting author e-mail address: nicoabel@icloud.com introduction: concussion is a complex pathophysiological process affecting the brain. the coach plays a pivotal role in the management of the concussed player. assessing the knowledge of the high school rugby coaches in south-africa may enable future education on the subject to focus on areas where knowledge is lacking. methods: a cross-sectional, descriptive study design was used with the aid of a validated questionnaire. first team rugby coaches of south african high schools were asked to complete questionnaire. relationships between total scores for different demographic groupings were established using non-parametric techniques due to the presence of small and uneven sample sizes of the groups. results: symptom recognition score of 78% and general concussion knowledge score of 80% compare well with international study results. maddock question knowledge score of 26% and return-to-play knowledge score of 62% were not adequate. educational programs (boksmart) is the most popular source of knowledge followed by healthcare providers. choice. boksmart accredited coaches did significantly better than the non–accredited coaches in the total score knowledge score (p=0.041). large category school coaches scored better in general concussion knowledge compared to small school coaches (p=0.0084). a significant difference was observed between the different coach age groups with the 35-44 year group indicating the best scores. less than 3 years in coaching and the least qualified coaches scored worse than the other groups. conclusions: south african high school rugby coaches do not have sufficient knowledge to manage the return-to-play of concussed players adequately. boksmart accreditation, the size of the school and the age group of the coaches were identified as predictors for superior knowledge. coaches at small schools were identified as a possible group with inferior knowledge of concussion. 58 p02: changes in heart rate variability while exercising in humid and high temperatures m bester 1, cc grant 1, p becker 2, dc janse van rensburg1. 1section sports medicine, faculty of health sciences, university of pretoria, south africa. 2 faculty of health sciences, university of pretoria, south africa. presenting author e-mail address: docmbester@gmail.com introduction: during competition in hot environments, endurance athletes often exercise/compete at intensities that stress their cardiovascular system. the primary aim of the study was to quantify the effect of increased core temperature (while exercising in a hot and humid environment) on autonomic cardiac control and to determine if heart rate variability (hrv) indicators may be indicative of a rise in core temperature. methods: the study was conducted in a climatic chamber where healthy male volunteers (n=14) exercised in a hot and humid environment for 120 minutes while core temperatures increased from normal, 37°c, to 39°c. rr interval data was continuously sampled for 120 minutes and compared with recorded baseline values (sampled during exercise in the same environment at normal core temperature: 37°c). results: increases in core temperature were accompanied with a rise in hr (84 bpm to 124 bpm, p=0.0034) which was largely due to vagal withdrawal and an overall decrease in all hrv indicator values: a)time domain indicators (mean rr: 663.64 to 502.86, p=0.0034; stdrr: 26.45 to 18.46, p=0.031; rmssd: 22.83 to 11.07, p=0.03; pnn50: 4.63 to 1.12, p=0.02), b) frequency domain indicators (lfms2: 437.86 to 141.50, p=0.011; hfms2: 197.29 to 45.89, p=0.0085) and c) non-linear hrv indicators (sd1: 16.34 to 8.09, p=0.036; sd2: 64.03 to 22.44, p=0.0099). however, indicators of autonomic balance all showed non-significant changes: lfnu: p=0.504; hfnu: p=0.517and lf/hf: p=0.395. indicators of complexity and selfsimilarity gave heterogeneous results (sampen and dfa). from the exploratory regression analyses, it was observed that mnrr (r²=0.463), mnhr (r²=0.59) and dfaα1 (r²=0.350) show the most promise with regards to hrv indicators that could act as predictive indicators of elevated core temperature. conclusion: quantification of hrv indicators in young and healthy athletes indicated that increases in core temperature, during exercise, decreased all variability measures while maintaining autonomic balance. furthermore, hrv indicators such as mnrr, mnhr and dfaα1 may have potential to indicate a rise in core temperature as there is a clear association between core temperature and these hrv indicators. 59 p03: the influence of match characteristics on post-match heart rate variability of male badminton players h, pienaar; b coetzee; ca bisschoff physical activity, sport and recreation research focus area, faculty of health sciences, northwest university, potchefstroom campus, potchefstroom, south africa introduction: the purpose of this study was to investigate the influence of match characteristics on the post-match heart rate variability (hrv) of male badminton players. methods: 22 male, african, singles badminton players (age: 23.3 ± 3.9 years) participated in the study. during 46 national and international matches players were fitted with a fix polar heart rate transmitter belt and a minimaxx global positional system (gps) unit to record variations in beat to beat (r-r) intervals for 60 seconds directly after play had stopped (post-match) and court movements during matches. results: moderate significant, inverse spearman’s rank correlations (p ≤ 0.1) were found between peak very-low frequency power (vlfp), distance covered, and time spent in the low intensity (liz) (rs = -0.42; rs = -0.33) and medium (rs = -0.41; rs = -0.41) intensity (miz) zones, respectively as well as between peak low frequency power (lfp) and time spent in the high intensity zone (hiz) during matches (rs = -0.33). peak high-frequency power (hfp) showed a moderate significant inverse correlation with absolute and relative heart rate (hr) in the liz (rs = -0.44) and a moderate significant positive correlation with the absolute and relative hr in the hiz (rs = 0.40). lastly, moderate significant inverse correlations were also observed between liz and miz total player load and vlfp, respectively (rs = -0.41; rs = -0.38). conclusions: therefore, match characteristics can significantly influence the post-match hrv of male badminton players, although the direction and nature of the influence are not in line with what previous research indicate. 60 p04: 66% of 1st year university medical students report low habitual physical activity levels jill borresen1, martin schwellnus1, paola wood2, kim nolte2, tanya camacho2, martin bac3, debashis basu4, gerda gericke5, amanda talma3, marianne schwellnus6 1sport, exercise medicine and lifestyle institute (semli), university of pretoria, south africa 2division of biokinetics and sport science, university of pretoria, south africa 3department of family medicine, university of pretoria, south africa 4school of health systems and public health, university of pretoria, south africa 5department of human nutrition, university of pretoria, south africa 6school of medicine, university of pretoria, south africa presenting author e-mail address: jill.borresen@up.ac.za introduction: physical inactivity is the number one cause of most chronic diseases, and the largest health gains are achieved with increasing habitual physical activity. exercise prescription is therefore an important part of patient counselling for healthcare professionals. research suggests that doctors who engage in aerobic exercise are more likely to ask and advise their patients on physical activity. and medical students that engage in strenuous exercise perceive exercise counselling as highly relevant to future clinical practice. therefore the physical activity habits of healthcare professionals is important, yet little has been published. methods: this cross-sectional, observational study involved 281 consenting 1st year mbchb and bachelor of clinical medicine practice (bcmp) students at university of pretoria (100 male, 181 female, mean age 19.9±2.7 years). the total score from the frequency intensity time index of kasari was used to classify current physical activity levels into low, moderate and high. outcome variables included prevalence of physical activity levels and frequency of cardiorespiratory, strength and flexibility exercise. chi square statistical test was performed to discern differences between male and female participants. results: 66% reported low levels of habitual physical activity (males 61%, females 68%; not significantly different (ns)), 16% report moderate levels (males 17%, females 16%; ns) and 19% report high levels of physical activity (males 22%, females 17%; ns). approximately 70% of students report doing fewer than 3 days per week of cardiorespiratory exercise. 77% do <3 days per week of strength-related exercises and 86% do less than 3 days per week of flexibility exercise. conclusions: the majority of 1st year medical students in this study report engaging in low levels of physical activity. these preliminary data form part of research identifying lifestylerelated risk factors that should be addressed, thereby informing the development and implementation of the healthy lifestyle programme for healthcare professionals (helphealth). 61 p05: the psycho-hormonal effects of aerobic fatigue on collegiate female soccer players adele broodryk,1 cindy pienaar,1 david edwards2 and martinique sparks1 1physical activity, sport and recreation research focus area, faculty of health sciences, north-west university, potchefstroom, south-africa; 2psychology department, university of zululand, private bag x1001, kwadlangezwa, 3886, south africa. presenting author email address: adele.broodryk@nwu.ac.za introduction: up to 95% of a soccer match entails aerobic actions that may cause fatigue. little is known about the effects of fatigue on the hormonal and psychological states of female players. methods: cortisol values (saliva sample), state anxiety (spielberger state-trait anxiety inventory) and mood scores [incredibly short profile of mood states (isp), comprising six subscales and total mood disturbances (tmd)] of 43 female players (aged 22.0 ± 2.7 years) were taken immediately prior to, and 15 minutes after, an aerobic fatiguing test (aft: yo-yo intermittent recovery test). results: cortisol increased (d = 0.7, p = 0.007) and isp–confusion and isp–vigour decreased (d = 0.5, p = 0.01 – 0.02). at pre-aft, a slight positive relationship between cortisol and anxiety-absence (r = 0.3, p = 0.05) was seen. tmd consistently demonstrated a strong relationship with all ispand anxiety scores (r > 0.4, p < 0.01). post-aft results demonstrated a positive relationship between cortisol and bla(r = 0.3, p = 0.04), isp–anger with hrmax (r = 0.3, p = 0.03), yyir-level and isp-fatigue (r = 0.4, p = 0.04), and rpe with isp–vigour (r = -0.4, p = 0.008) and isp-fatigue (r = 0.3, p = 0.05). conclusions: fatigue caused by prolonged activity may be a greater physiological than psychological stressor, though both may affect soccer performance. we recommend training players to increase their aerobic capacity to ensure maximal quality match-time before fatigue and its subsequent adverse physiological and psychological effects set in. 62 p06: effect of sports massage on lactic acid clearance during recovery from anaerobic exercise. robyn burrows1, grant de wet1, susan h bassett1 1department of sport, recreation and exercise science, university of the western cape, cape town, south africa presenting author e-mail address: robyntoniburrows@gmail.com & 2grant7@gmail.com introduction: research on the use of massage to enhance recovery has produced ambiguous findings in recent years. athletes and physiotherapists typically believe that massage can aid recovery, but there is insufficient scientific evidence to support this thinking. during recovery after exercise, the body must restore the energy substrates it has used, remove metabolic waste products and repair the body’s tissues. therefore, increased blood flow during recovery from high intensity exercise is important as it allows for the efficient transport of lactic acid from within the muscle via the blood to the heart. this allows the heart enzymes to convert lactic acid to pyruvate for further energy metabolism in the body. therefore the aim of this study was to ascertain whether sports massage is an effective treatment modality for the clearance of lactic acid during recovery in university sports people. methods: twenty healthy university hockey and cricket players (aged 20-26 years) participated in the study. a 30s wingate anaerobic test was conducted to ensure high levels of blood lactic acid was generated. the resistance of the cycle ergometer during the test was calculated as 0.75% of body weight. participants warmed up on the monark® stationary bicycle at 60 rpm for 2 minutes (with intermittent bursts of rapid pedalling), followed by a 30 s rest, after which the wingate test commenced. blood lactic acid levels were measured immediately post-exercise, 2 minutes after active recovery was completed, and at 5 and 10 minutes into the massage and passive recovery interventions. statistical analysis was conducted using descriptive statistics in the form of means and standard deviations in order to describe the data. the dependent variables were compared between the two groups using an independent t-test. the level of significance was set at p<0.05. results: no significant differences were noted between the various lactic acid test phases, however, the massage group displayed a 0.9% decrease in blood lactic acid concentration from 2 minutes of active recovery to 5 minutes into the massage intervention and, similarly, the passive recovery group also showed a decrease of 0.8% in blood lactic acid concentrations during this period. from 5-10 minutes of recovery intervention, the massage group had a 1.1% decrease in blood lactic acid levels whereas the passive recovery group showed a 1% increase. both groups showed a similar overall decline in blood lactic acid concentrations throughout the 10 minutes of the recovery interventions. conclusion: although no significant differences were observed in blood lactic acid concentrations after high intensity exercise following 10 minutes of leg massage or supine passive recovery with legs elevated, blood lactic acid reduced at a faster rate during passive recovery than massage. this is only an indication of muscle lactic acid and massage may be flushing the muscles of lactic acid more effectively, hence the higher blood lactic acid concentrations compared with active recovery. therefore it can be concluded that either recovery modality could be considered to be effective for clearing blood lactic acid following high intensity anaerobic exercise. 63 p07: comparative upper-quarter posture analysis of female adolescent freestyle swimmers and non-swimmers carolin-mari botha1, francè rossouw1 & tanya c. ds. camacho1 department of physiology, division of biokinetics & sport science, university of pretoria, pretoria, south africa presenting author e-mail address: tanya.camacho@up.ac.za introduction: the recurrent and demanding upper-quarter limb movement patterns imposed by freestyle swimming, may lead to adaptive muscle length and tension changes, predisposing adolescents swimmers to postural malalignment, pain and injury. the study aimed to record and quantify the static upper-quarter postural alignment of competitive female adolescent freestyle swimmers, and to compare their results to their non-swimming peers and to normative values. methods: the evaluation group (eval) consisted of 35 competitive swimmers (age: 15±3 y; stature: 166.5±9.9 cm; body mass: 65.5±7.7 kg) and the control group (con) of 36 peers (age: 15±3 y; stature: 164.2±6.7 cm; body mass: 62.1±9.1 kg). sagittal posture was assessed by photographic posture analysis. median ± interquartile range and inter-group differences were calculated utilising stata 13 software. results: analysis showed significant differences (p = 0.00) between groups for all variables, with eval demonstrating restricted median scores for head-tilt angle (-8.7°), cervical angle (13.3°), and protractionand retraction angle (-24°) and a higher score for thoracic angle (+7.4°), when compared to con. furthermore, the median scores of eval deviated from accepted normative values for head-tilt angle (-4.6°), cervical angle (-16.5°), protractionand retraction angle (-15°) and thoracic angle (+21.2°). therefore, eval demonstrated all measurement deviations indicative of risk for forward head with rounded shoulder postural malalignment. however, two median scores demonstrated by con also deviated from the norm indicating a risk for forward head (cervical angle -3.2°) and mid-thoracic kyphotic posture (thoracic angle +13.8°). conclusions: adolescents risk developing upper-quarter postural malalignment possibly from poor postural habits. in this group of participants, however, the risk for postural malalignment and its associated risk for future pain and injury, may have been exacerbated by years of freestyle swim training. 64 p08: dermatological conditions in recreational athletes participating in a mass community-based running event i h chauke 1, m schwellnus1,2,3, cc grant 1, d a ramagole 1, s swanevelder 4, e jordaan 4,5. 1sport, exercise medicine and lifestyle institute (semli) & section sports medicine, faculty of health sciences, university of pretoria, south africa, 2international olympic committee (ioc) research centre, pretoria, south africa, 3faculty of health sciences (emeritus professor), university of cape town, south africa, 4biostatistics unit, south african medical research council, cape town, south africa, 5statistics and population studies department, university of the western cape, south africa. presenting author e-mail address: rina.grant@up.ac.za introduction: dermatological conditions experienced by runners are recognized to be of increasing significance because of high incidence rates noted at running events. it is therefore important to investigate the incidence rates and associated risk factors to implement preventative measures. the aim of this study was to determine the incidence of, and risk factors associated with dermatological complications in the two ocean’s half marathon (21.1km) and ultramarathon (56km) runners. methods: dermatological complications (defined as any runner with a skin complication during the race, requiring assessment by a clinician) were recorded over an 8-year period during the two-ocean marathon race event (2008 2015). a total of 153 206 runners (92 038 males and 61 168 females) participated. results: dermatological complications had an average incidence of 1.34/1000 race starters for all runners (95% ci: 1.10-1.63). the incidence for the 21.1km marathon were 1.2/1000 race starters (95% ci: 0.95-1.60) while the incidence for the 56km marathon averaged 1.51/1000 race starters (95% ci: 1.13-2.02). the highest incidence recorded was in the 56km race participants (2013) was 3.40/1000 race starters (95% ci: 2.38-4.86). the 21.1 km runners showed the highest incidence in 2014 (1.95/1000 race starters, 95% ci: 1.32-2.88). multivariable risk factor analysis indicated that the specific year of observation was a significant risk factor in the half marathon (p=0.014) and in the ultra marathon (p<0.0001). this may indicate a link with environmental conditions. the multivariable analysis furthermore indicated that for the half marathon, older age (51+years), (p=0.017) and for the ultra marathon experience were significant risk factors (p=0.014). conclusion: prevention strategies to reduce the risk of dermatological complications should focus on older participants, inexperienced ultra marathon runners and developing management strategies to negate the effect of adverse environmental conditions. 65 p09: relationships between inand post-match heart rate recovery and heart rate variability of african badminton players ben coetzee1 1physical activity, sport and recreation focus area (phasrec), faculty of health sciences, north-west university, potchefstroom campus, potchefstroom, south africa presenting author e-mail address: ben.coetzeee@nwu.ac.za introduction: the purpose of the study was to determine relationships between inand postmatch heart rate variability (hrv) and heart rate recovery (hrr) of male, african, singles badminton players. methods: twenty-two male, african, singles badminton players (age: 23.3 ± 3.9 years) participated in the study. fix polar hr transmitter belts were used to record variations in beatto-beat (r-r) intervals for rest periods between sets (in-match) and for 60 seconds directly after play had stopped (post-match) for 46 matches. absolute and relative hrr were also calculated at 60 seconds post-set or -match. results: cluster analyses reduced hrv-related variables and hrr were entered into forward stepwise multiple regression analyses. the level of significance was set at p≤0.05. natural logarithmic transformation of the square root of the mean squared differences between successive r-r intervals (ln-rmssd: beta=0.57, p=0.08) and the very low band peak frequencies in hertz (peak vlf hz: beta=-0.44, p=0.033) acted as significant predictors of both inand post-match hrr. the high band peak frequencies in hertz (peak hf hz: beta=-0.83, p=0.000) and the natural logarithmic transformation of high frequency relative power expressed as normalised units (ln-hfnu: beta=1.28, p=0.01) were also identified as significant predictors of inand post-match hrr, respectively. conclusions: most of the parasympathetic nervous system-related hrv parameters are significantly associated with changes in hrr during and after badminton matches, although the direction of relationships are not always accurate. therefore, the assumption that specific hrv-related variables always reflect activity of certain branches of the autonomic nervous system may be inaccurate. 66 p10: tackle and ruck technical proficiency in rugby union and rugby league: a review steve den hollander 1-3, chanda ponce 1, mike lambert 1-2, ben jones 1, 4-8, sharief hendricks 1-2, 4 1division of exercise science and sports medicine, department of human biology, faculty of health sciences, the university of cape town and the sports science institute of south africa, cape town, south africa; 2health through physical activity, lifestyle and sport research centre (hpals), faculty of health sciences, the university of cape town, south africa; 3western province rugby academy, cape town, south africa; 4carnegie applied rugby research (carr) centre, institute for sport, physical activity and leisure, leeds beckett university, leeds, uk; 5yorkshire carnegie rugby union football club, leeds, uk; 6 leeds rhinos rugby league club, leeds, uk; 7england performance unit, the rugby football league, leeds, uk; 8school of science and technology, university of new england, nsw, australia. presenting author e-mail address: steve_dh1989@hotmail.com introduction: research on tackle and ruck technique proficiency has been shown to improve performance and reduce injury risks in rugby union (ru) and rugby league (rl). one of the main aims of this research is to provide coaches with information to inform practice. with that said, a complete review of the research on tackle and ruck contact technique to date has not been consolidated and synthesised in manner for rugby stakeholders to assimilate. therefore, the purpose of this review was to consolidate and synthesise ru and rl studies on tackle and ruck contact technique for rugby stakeholders. methods: three electronic databases were searched for peer reviewed research studies which analysed any technical movement pattern of a player in the tackle, ball-carry into contact, or ruck. forty-one papers were identified (19 in rl and 22 in ru). results: research in rl primarily focussed on identifying factors that impact tackling ability. leaner, fitter players, with greater lower body strength, tended to have more proficient tackle technique. experience and level of play were positively associated with tackling ability. research in ru focussed on identifying tackle and ruck techniques associated with performance measures and injury outcomes. eleven tackle techniques and five ball-carrier techniques were associated with both performance measures and injury outcomes. only one study analysed ruck technique in ru, related to injury outcomes, and further research identifying safe and effective ruck technique is recommended. conclusions: the findings of ru research support national injury prevention programmes that advocate that safe contact technique is also effective technique. research in rl highlight the importance of developing tackle technique and physical qualities to allow players to allow players to progress to higher levels. further research describing the relationship between tackle technique and performance measures and injury outcomes in ru and research identifying factors associated with tackle and ruck proficiency in ru is recommended. 67 p11: head and neck injuries sustained during the super rugby tournament: a prospective study involving 69 781 training player-hours and 6 520 match player-hours c du plessis1, cc grant 1, m schwellnus1,2,3, a jansen van rensburg1, c janse van rensburg4, e jordaan5,6. 1sport, exercise medicine and lifestyle institute (semli) & section sports medicine, faculty of health sciences, university of pretoria, south africa, 2international olympic committee (ioc) research centre, pretoria, south africa, 3faculty of health sciences (emeritus professor), university of cape town, south africa, 4biostatistics unit, south african medical research council, pretoria, south africa, 5biostatistics unit, south african medical research council, cape town, south africa. 6statistics and population studies department, university of the western cape, south africa. presenting author e-mail address: rina.grant@up.ac.za introduction: professional rugby union is a high-intensity collision sport and is known to have a high risk of head and neck injury (hni). the aim of this study was to determine the incidence rate of hni during the 2013 2016 super rugby tournaments, and identify the associated injury risk factors. methods: all elite male south african rugby players (n=868) that participated during the 2013 2016 annual super rugby competition were included. injury and exposure (days) data (training and match) was collected daily by each team physician, through a secure, web-based electronic platform. results: thirteen point three percent of players sustained hni during the 4 year period of the tournament, with an overall incidence rate (ir/1000 player-hours; 95% ci) of 1.5 (1.2-1.8). match hni were significantly higher (16.4; 13.4-19.8) compared with training hni (0.1; 0.00.2). the head/face region was more commonly injured (70.4%) than the neck/cervical spine area (29.6%) for all injuries, as well as during match play for both areas: 72% vs. 28% respectively. the majority of injuries were of minimal or mild severity (>57.4%). moderate and severe injuries accounted for 35.7% and 7.0% of all injuries, respectively. in the head/neck region, match injury to the brain/cns (53%) were nearly four times higher than injury to muscle/tendons (14%), joint/ligaments (9%), and skin or bone (11% each). tackling was indicated as the main mechanism of injury in concussion injuries (52%), brain/cns (50%) and head/neck (44%) injuries, followed by being tackled (25%, 24% and 19% respectively) and collision (14%, 15% and 13% respectively). front line players had a higher incidence of overall hni (front line=1.7; 1.3-2.1: backline= 0.3; 0.9-1.7) and match hni (front line=18.7; 14.4-23.8: backline = 13.8; 9.9-18.7). conclusion: the overall incidence of hni in super rugby is 1.5/1000 hours play with a 10 times higher incidence during matches (16.4). most hni are to the brain/cns and occur as a result of tackling or being tackled. front line players are at a higher risk compared to backline players. risk management structures need to be developed to reduce the risk of hni in super rugby. 68 p12: work-related barriers encountered by football medical team in eswatini adiele dube¹ and chantell gouws² ¹department of health education, southern africa nazarene university, eswatini ²department human movement science, university of zululand, south africa presenting author e-mail address: adieledube@yahoo.com introduction: football is among the most reported sport to incur a high rate of soft and hard tissue injuries in the world and eswatini, in particular. the country has suffered deaths of junior and senior football players in the past two seasons consecutively. research has shown that there is a high turnover of football team medical team in the country. therefore, the current study aims to investigate work-related barriers encountered by the team medical team in the kingdom of eswatini. methods: twenty eight football team medics were purposively recruited to participate in this study. data was collected through interviews and focus groups on the perceived hindrances to medical team management. cronbach’s-alpha method was used and it yielded a reliability coefficient of 0.83. results: it was identified that there was lack of support for team medics for premier, super and promotional leagues, unfair treatment to medics in terms of contractual system, inadequate salary/incentives, unfavorable working conditions, inadequate resources and pressure for players to return to play (from technical and management staff) as major barriers to effective job satisfaction for team medics. lack of opportunities for promotion, lack of time, and family commitments were reported as the least barriers encountered by medics. conclusion: it is recommended that the eswatini football association, through the national sports medicine executive committee should consider these findings and develop remedial measures to improve the challenges team medics are facing. the association should also ensure that there is encouragement of more female team medics in the game of football. 69 p13: blood pressure responses over 24-weeks of rehabilitation using robotic locomotor training and activity-based training in persons with spinal cord injury (sci). robert evans1, claire shackleton1, sacha west 2, laurie rauch1, wayne derman3,4, yumna albertus1 1 division of exercise science and sports medicine, department of human biology, faculty of health science, university of cape town, cape town, western cape, south africa 2 department of sports management, cape peninsula university of technology, cape town, western cape, south africa 3 institute of sport and exercise medicine, division of orthopaedic surgery, faculty of medicine and health sciences, university of stellenbosch, cape town, south africa. 4 ioc research centre, south africa presenting author e-mail address: robertevanssa@gmail.com research objective: evaluate the effect of robotic locomotor training (rlt) compared to activity-based training (abt) on blood pressure responses in persons with sci. design: randomized controlled trial. setting: therapy & beyond rehabilitation centre walking with brandon foundation. participants: volunteer sample of 16 participants, aged 19 – 60 years, with chronic (>1 year) traumatic motor incomplete sci (c1-c8; asia c-d) were randomized into rlt (n=8) and abt (n=8) groups. interventions: the rlt and abt interventions involved 60-minute sessions, three times per week, over 24-weeks. rlt exclusively used the ekso gt exoskeleton. abt involved resistance, cardiovascular and flexibility training. main outcome measures: brachial and ankle blood pressure. short-term results: supine diastolic bp was well-regulated at 6-weeks in the rlt group whilst it significantly lowered in the abt group (mean difference = 7.13mmhg; 95% ci, 0.42-13.83; p = 0.03). doppler ankle bp showed a significant increase after exercise in the rlt group at 4-weeks (mean increase = 19.31mmhg; 95% ci, 4.35-34.28; p = 0.003). long-term results: post-exercise diastolic bp was reduced in the abt group at 20-weeks (mean difference = 13.13mmhg; 95% ci, 0.01 – 26.24; p = 0.04). post-exercise doppler ankle bp significantly increased in the abt group at 16-weeks (mean increase = 19.56mmhg; 95% ci, 4.60-34.53; p = 0.002). conclusions: rlt and abt demonstrated positive effects on peripheral circulatory function, however these benefits occurred at different time points. rlt showed changes in bp within 6 weeks, whereas abt showed changes in bp later during the intervention period (16-24 weeks). long-term benefits of abt may be attributed to the unique resistance training component of the intervention. 70 p14: the epidemiology of injury and illness of athletes at the indian ocean island games 2019 daniel garnett1, adisha bholah2, yannick d’hotman2, krsnamoortee sunassee2, jon patricios3, benita olivier 4, saul cobbing1 1 physiotherapy department, college of health sciences, university of kwazulu natal, 2 comité d’organisation de la 10ème edition des jeux des iles de l’océan indien (coji 2019), mauritius, 3 the wits initiative for sport and health, faculty of health sciences, university of the witwatersrand 4 physiotherapy department, faculty of health sciences, university of the witswatersrand. presenting author e-mail address: danielphysio@gmail.com introduction: the 10th indian ocean island games (ioig) was held in mauritius from the 19 to 28 july 2019, this multi-sport event occurs every four years with athletes from seven islands of the indian ocean. this study to establish the extent of injury and illness of participating athletes was the first in the games’ 40-year history. methods: this prospective cohort study recorded athlete injury and illness data by medical personnel from the visiting islands and the host country during 14 sporting codes at 16 venues. the injury and illness reporting form was adapted from versions used at recent olympic games. results: in total, 1521 athletes (531 women and 990 men) reported 160 injuries and 85 illnesses. the age of patients ranged from 10 to 59 years (mean: 25.21 years). an injury incidence of 12% and illness incidence of 6% were recorded. the highest number of injuries was documented in football (24%) and basketball (14%). men suffered the majority of injuries (79% vs 21%), with most injuries occurring during matches/heats compared with training (57% vs 43%). the lower limb (63%) was most frequently injured with the most common sites being the thigh (20%), knee (18%) and calf (11%). joint sprains were the most common type of injury (27%), followed by muscle strains (20%). the highest number of injuries was sustained from contact with other athletes (28%). the highest incidence of illness occurred in athletes participating in athletics (21%) and volleyball (15%) and men reported more illness than women (57% vs 43%). the majority of all illnesses affected the respiratory system (67%) and infection was the most common cause of illness (84%). conclusion: at least 12% of all athletes sustained an injury and 6% sustained an illness during the games. analyses of illness risk factors and injury mechanisms is essential to direct future athlete welfare policies. 71 p15: a description of cardiovascular disease risk factors in a sample of factory workers in johannesburg dr philippe gradidge centre for exercise science and sports medicine, university of the witwatersrand philippe.gradidge@wits.ac.za the aim of this cross-sectional study was to describe the cardiovascular disease risk factors of a sample of factory workers in johannesburg, south africa. a sample of 145 employees out of a potential 220 volunteered to participate. point-of-care glucose, total cholesterol, blood pressure, and anthropometry were collected. sociodemographic information, self-reported sleep, physical activity, and mental health were determined using questionnaires. descriptive analyses were used to compare male and females participants. females were younger in age, had higher body mass indices, but showed lower cardiovascular risk than males (p0.005 for these measures). hypertension and depression were noted in ~30% of males and females, with high levels of stress in the study population. a high proportion of both males and females were current smokers and consumed alcohol regularly. the consumption of fruits and vegetables were relatively high in the sample, and most perceived themselves as physically active. in conclusion, this descriptive study has shown that the presence of cardiovascular diseases risk factors are high in active factory workers, despite adherence to protective behaviours. 72 p16:the ukumela impilo study to interrupt sedentary behavior and improve cardiovascular health dr philippe gradidge centre for exercise science and sports medicine, university of the witwatersrand philippe.gradidge@wits.ac.za the study aims to understand and address the sedentary behaviour and correlates of cardiometabolic diseases in a sample of office based workers. the ukumela impilo study is a randomised controlled trial based in at a company in johannesburg. phase one of the study aims to understand the sedentary behaviour and correlates of cardiometabolic diseases in a sample of office based workers. the sample will then be randomly assigned into one of two potential intervention groups and a control group, including a standing desk group, a group receiving health messages, and the control group. in phase two, follow-up testing will take place post-12-week intervention to determine the changes in sedentary behaviour and cardiometabolic diseases. focus groups will be conducted in phase 3 of the study to determine the experiences of the sample engaged in the two intervention groups. the purpose of this paper is to describe the development of a conceptual model to test the efficacy of the two interventions in the office-based workers. in conclusion, the researchers, in consultation with stakeholders, will formulate a sustainable model for addressing extended sitting in office-based workers. 73 p17: the effects of foam rolling and stretching as recovery tools on power output, mood state, muscle stiffness, and muscle pain claassens m1, hammill hv2 1. department of biokinetics, university of zululand, south africa 2. school for human movement sciences, north-west university, potchefstroom campus, south africa (phasrec) presenting author e-mail address: henriëtte v. hammill; 1278221@nwu.ac.za. introduction: recreational sportsmen strive to improve performance while increasing their training load. muscle pain and -stiffness can occur after an increase in exercise intensity and volume, after eccentric muscle contraction. when recreational sportsmen persevere in training whilst experiencing muscle pain, poor coordination and mood state can be experienced; which can lead to a reduction in muscle strength. methods that have been used to decrease muscle pain, such as massage and vibration therapy are expensive and impractical. this study aims to discover an inexpensive recovery tool that decreases muscle pain and -stiffness whilst simultaneously improving muscle strength and mood state. foam rolling (fr) and static stretching (ss) are considered possible suitable recovery tools. methods: sixty-seven (n=67) healthy, recreational sportsmen were recruited from sport clubs in kwa-zulu natal to voluntarily participate. participants were divided into: the fr group (n=23), the ss group (n=25) and a control group (n=19). power output [maximum voluntary concentric (mvc)] and mood state [profile of mood status (poms)] were measured on all participants at baseline, after which muscle pain and -stiffness were induced (through eccentric hamstring exercise session). power output and mood state were then measured 48 hours post eccentric exercise session. following these measurements the fr and the ss groups commenced with a three-day intervention, performing either fr or ss on the hamstring. the control group performed no intervention. muscle pain and -stiffness were measured on all participants at baseline, three times a day for two days post intervention. mood state was measured 24 hours and 48 hours after the eccentric exercise. an analysis of variance (anova) was conducted with a significance level of ≤0.05. results: both fr and ss significantly reduce eccentrically induced hamstring muscle pain (p<0.05). no statistical difference in muscle stiffness between groups was recorded. the fr group’s muscle stiffness is continuously lower than that of the ss and control group. in all groups, vigour, a component of mood state, decreased over the course of the intervention. while this means that a decrease in performance can be expected, no significant decrease was found between groups. this can be due to numerous external stress factors experienced by each participant during the day. the fr group reveals a strength output loss (p<0.31), whereas the control group (p<0.000) and the ss group (p<0.002) reveals a more significant strength output loss. evidence suggests that using fr compared to ss as a recovery tool will be of greater benefit as concerns the improvement of strength output. recreational sportsmen can thus strive to achieve optimal performance whilst continuously increasing training. conclusions: fr and ss are safe, practical, and inexpensive tools that can assist in decreasing muscle pain after a strenuous bout of eccentric exercise. although ss is historically a widely used recovery tool, it may not be the best tool for the improvement of performance. only fr was shown to prevent strength loss and improve muscle stiffness as compared to ss and control group. 74 p18: “i am active and healthy, so i don’t need to make lifestyle changes!” a short report of clinical markers of “risk” for ncd’s versus health and physical activity perceptions in a low-resourced setting.” brittany fell1,2,3, ashleigh robinson1,2,3, susan hanekom2, wayne derman1,3, martin heine1,2,3 1 institute of sport and exercise medicine, faculty of medicine and health sciences, stellenbosch university 2 division of physiotherapy, faculty of medicine and health sciences, stellenbosch university 3 ioc research centre, cape town, south africa presenting author e-mail address: brittany@sun.ac.za introduction: it is important to understand how to facilitate behaviour change in the context of healthy lifestyle, where gratification is often delayed and not directly noticeable, to prevent and manage ncd risk factors. the objective of this cross-sectional and pragmatic study was to determine clinical markers of ncd risk in a low-resourced and socio-economic challenging neighbourhood, and to determine the association between key commonly measured health parameters with self-reported levels of physical activity and perceived health. methods: bishop lavis (cape town, south africa) is a low-resourced and socio-economic challenging neighbourhood. all participants of the annual bishop lavis health festival (friday 19th of october 2018) were requested to complete a fully anonymous “health passport”, which included gender, age, smoking, alcohol, drug-use, work status, medical insurance, and selfreported presence of non-communicable disease (i.e. cancer, cardiovascular disease, respiratory disease or diabetes). perceived levels of current physical activity and perception of health were recorded using a simple likert scale ranging from 1 (unhealthy; inactive) to 5 (very healthy, very active). results: out of the 104 participants, 63% presented with blood pressure recordings indicative of hypertension. a majority of the participants (58.1%) could be categorised as obese (class i–iii). non-fasting blood glucose concentrations could be considered normal in most participants (81.6%). participants reported on average a 4.1 (±1.0) in terms of engaging in habitual physical activity, and 4.0 (±1.1) in terms of health on a 5-point likert scale. only the bivariate association between systolic blood pressure and reported physical activity was found significant (p<0.05). conclusions: this pragmatic study exemplifies that these participants, living in a challenging socio-economic context, portrait a clinical risk profile in line with that for the development and presence of ncd. however, these risks did not reflect in point-estimates of perceived physical activity and health. 75 p19: performance and anthropometrical differences between sexes at the onset of puberty charné scott1, kirsty elliott1,2, james clark1,2, cassidy grobler3, mariska fisher3, charl janse van rensburg4 1sport, exercise medicine and lifestyle institute (semli) and division of biokinetics and sports, 2science, department of physiology, faculty of health sciences, university of pretoria, 3department of sport and leisure studies, university of pretoria, 4biostatistics unit, south african medical research council presenting author e-mail address: charne.scott@semli.co.za introduction: understanding anthropometric and physical performance capability between youths of similar maturational status (pre-pubertal) but in different sexes, is needed to guide professionals in the prescription of exercise and sport. the aim of this study was to compare anthropometric and physical performance parameters in pre-pubertal (pre-peak height velocity; pre-phv) girls and boys. methods: 62 active youths (age = 11.7 ± 1.0 yrs.; females = 37, males = 25), were classified as pre-phv, according to maturity status (mirwald equation). anthropometric measures (height, weight, body fat percentage, arm span, leg length, seated height) and physical performance tests (grip strength, vertical jump, prone bridge, modified sit and reach) were compared between girls and boys with the same maturity status. results: chronological age and anthropometric measures (height, weight, absolute arm span, absolute and relative seated height and absolute and relative leg length) were significantly higher in boys compared to girls (p=0.05), but body fat percentage was not different between girls and boys. within the performance tests 1) boys scored significantly higher in absolute grip strength (r, p=0.00; l, p=0.00) absolute vertical jump height (p=0.008), and relative grip strength (kg/kg; mean ± sd)(left) (boys = 0.52 ± 0.12; girls = 0.45 ± 0.09; p=0.018), 2) girls scored significantly better than boys in absolute modified sit-and-reach test (p=0.05), and relative to stature (boys = 0.19 ± 0.03; girls = 0.24 ± 0.07; (cm/cm) p=0.01), and 3) there was no significant between-sex difference in relative vertical jump height (p=0.07) and absolute prone bridge time to exhaustion (p=0.29). conclusions: in absolute performance measures there were significant differences between prepubertal boys and girls, and therefore, prescription of exercise and sport should be tailored accordingly. 76 p20: the kinetics and kinematics of the rotary backlift neil isaacs dr.isaacs@ballitomedical.co.za private general practice, ballito, south africa background: video analysis has revolutionized coaching with slow motion replays now becoming available to anyone with cell phone capability of 200 frames per second. the era of pre and post video analysis has closely coincided with increased interest in the rotary batting technique with highlighted findings of a more lateral backlift. aims: a review of the backlift by slow motion video analysis of don bradman and modern top international ranked players to obtain aspects of the rotary batting technique with regard to functional anatomy related to rotations around the long axis of the limbs, trunk and bat with comparison to traditional coaching. methods: this is a descriptive observational study. slow-motion videos of footage of don bradman and replays of top international batsman were reviewed by taping the slow-motion videos of the backlift in turn with the slow-motion function of an apple iphone7. results: backlift loop divided into stages: stage 1: the backlift of don bradman involved flexion of the elbows from pointing the face of the bat to midwicket in the stance, to lifting the bat horizontally pointing to gully by extending the shoulders and flexing the elbows till the bat was in the same horizontal plane of the elbows. stage 2: the front shoulder internally rotates, using the back hand as a fulcrum, the bat lifts into a vertical position as the back wrist cocks (radial deviation), the back shoulder extends with the back forearm still directed towards cover. the backlift may end in stage 2 or continue to any point at the end of stage 3. stage 3: abduction of the back shoulder elevates the hands and forearm to the level of the back shoulder with the bat still vertical, maintaining the forearm and bat face directed to point, the back forearm supinates, keeping the bat vertical. from the stance to the top of the backlift, the edges of the bat were directed in the plane of the pitch. external rotation of the front hip may initiate rotation and closing of the hips and shoulders. discussion and conclusions: during stage 1, the centre of mass (com) shifts towards gully. preparation for the stride starts during stage1.moment of inertia (moi) of the arms and bat is reduced by extension of the back shoulder and flexion of the elbow. at the end of all stages, the hands are further to the off side compared to traditional coaching, allowing flexibility. forward strides keep the bat close to the com, optionally moving the hands forwards upwards and backwards in a semicircle, aiding propulsion in the direction of the stride. similarly, backward strides rotate the hands backwards and upwards. sideways movement to the off side is aided by flexing the back shoulder and flexion or extension enables flexibility of the vertical pendulum line of the downswing. traditional coaching and studies reveal an increased moi, the elbow above the back hand and the back shoulder internally rotated to form a figure 6 with the arms at the end of the backlift. 77 p21: the kinetics and kinematics of the rotary downswing in batting neil isaacs dr.isaacs@ballitomedical.co.za private general practice, ballito, south africa background: research on cricket batting is limited with mainly descriptive studies. findings of a more lateral backlift in the best players of the last century against traditional coaching of a straighter backlift towards the stumps raises the question as to the reason why. aims: a review of the downswing by slow motion video analysis of don bradman and modern top international ranked players to obtain aspects of the rotary batting technique around the long axis of the limbs and trunk and related functional anatomy to improve the velocity of the bat (performance) compared to traditional coaching. methods: this is a descriptive observational study. slow motion videos of footage of don bradman and replays of top international batsman were reviewed by taping the slow-motion videos of the downswing in turn with the slow-motion function of an apple iphone7. results: downswing stages: stage 1: the back hip horizontally abducts while flexed up to 90 degrees, after the pelvis closed and the back hip adducted with a varus or neutral back knee in the rotary backlift, opening the pelvis. shoulders close, back shoulder externally rotates and adducts the elbow to the waist. back forearm supinates and wrist extends obtaining the bat in the direction of the pendulum swing until the bat is horizontal. stage 2: back hip externally rotates while the shoulders open towards direction of shot, after xfactor stretch, passively externally rotating the back shoulder. the back elbow remains close to the waist, forearm supinated and wrist extended. double pendulum formed by front arm and bat is released as late as possible. bat face is directed to point in stage 1 and 2 in vertical pendulum shots. stage 3: active internal rotation of back upper arm occurs immediately before impact, after horizontal adduction accelerates the back upper arm, still externally rotated, into the scapula plane. pronation of the back forearm, flexion and ulnar deviation of wrist occurs through impact. front foot and back foot are in the direction of the shot in front and back foot vertical pendulum shots respectively. discussion and conclusions: stretch reflexes of the back hip, trunk and back shoulder add power to the shot. at impact the hips and shoulders are open compared to shoulders rotating vertically in traditional coaching. back upper arm moves from external rotation to internal rotation compared to being internally rotated from top of backswing to impact in traditional coaching. “o” grip noted increases moment of inertia around back upper arm and with opening of the shoulders, concern of deviation off the line of the downswing to the off side in vertical pendulum shots and above the horizontal pendulum in cross bat shots is allayed. lateral flexion occurs at the lumbar spine to increase the thoracohumeral angle closer to 90 degrees increasing the bat velocity. impact is away from the front foot in front foot drives and back foot in backfoot drives. 78 p22: exercise may decrease syncope secondary to postural change in females with rheumatoid arthritis: pilot study dina c (christa) janse van rensburg1, ja ker2, cc grant1, l fletcher3 1 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 2 internal medicine, faculty of health sciences, university of pretoria, south africa 3 department of statistics, faculty of natural and agricultural sciences, university of pretoria, pretoria, south africa. presenting author e-mail address: christa.jansevanrensburg@up.ac.za introduction: the autonomic nervous system (ans) regulates heart rate via sympathetic and parasympathetic influences. rheumatoid arthritis (ra) patients suffer from autonomic dysfunction, which may consequently lead to syncope with possible falls after posture change i.e. rising from supine to standing position. previous research has shown general ans improvement after exercise, but not in specific relation with posture change. the aim of this study was to determine the effect of exercise on posture change (supine to standing) in females with ra as measured by short-term heart rate variability (ans function). methods: patients with confirmed ra were randomly selected to a control(rac) or exercise group (rae). rae group (n=19) trained 2-3 times/ week under supervision. rac group (n=18) continued their current sedentary lifestyle. the medium intensity exercise programme lasted 12 weeks. no medication change was allowed during this time. ans function and balance were determined by quantification of the inter-beat interval variability, with the polar 810i heart rate monitor system. frequency domain analyses were used for quantification: lf (ms²) – mainly sympathetic influence; hf (ms²) – parasympathetic influence; and lf/hf – autonomic balance. results: the two groups’ baseline demographic data (age, sex, disease activity, disease duration) matched. comparing preto post posture change intervention (i.e. standing value minus supine value), all frequency domain parameters changed as anticipated (i.e. vagal withdrawal and increased sympathetic influence) for the rae group. the rac group’s measurements deteriorated: lf (ms²): rae -1.03 to 22.03 (stronger sympathetic influence); rac 43.45 to 31.21 (weaker sympathetic influence); hf (ms²): rae -24.03 to -33.34 (better vagal withdrawal); rac -191.7 to -114.1 (less vagal withdrawal); lf/hf: rae 10.57 to 15.04; rac 2.9 to 7.6. conclusion: preliminary results indicate that exercise may indeed improve autonomic function in ra patients, in such a way that posture change will not be an added burden for falls in an already otherwise compromised population. 79 p23: exploring the efficacy of low-level laser therapy and exercise for knee osteoarthritis a kholvadia, bhms, hms (hons), ma (hms); d constantinou, mbbch, bsc(med)hons, msc med, mphil, ffims, facsm; p j-l gradidge, b sp sc, b sp sc (hons), msc med, phd background: knee osteoarthritis (koa) is a prevalent, chronic disorder with excessive functional, social and economic burdens. the goal of treatment is to alleviate the symptoms and slow the progression. documenting the effects of exercise and lllt as co-modalities in the management of koa allows practitioners to implement this management tool as part of koa rehabilitation, resulting in the earlier discharge from a supervised rehabilitation setting. objective: the purpose of this study was to determine the effect of low-level laser therapy (lllt) in the treatment of knee osteoarthritis (koa). a randomised controlled trial (rct) was conducted on 111 participants (aged between 40-75 years) diagnosed with koa. participants were randomised into an exercise (n=39), lllt (n=40), or a combined exercise-lllt (n=32) group. methods: the western ontario and mcmaster universities osteoarthritis index (womac) scale was used to assess pain and functionality. knee range of motion was assessed using a goniometer, and the one-minute timed sit–to-stand test measured physical functionality at four time points: (t1) baseline, (t2) post 12-session intervention, (t3) one-month post intervention and (t4) three-month’s post intervention. knee circumference was measured using a measuring tape. results: womac pain and functionality scale and knee circumference scores decreased in all three groups (p<0.05), but the combined exercise-lllt group demonstrated better outcomes than the lllt or exercise alone groups respectively. the combined exercise-lllt group showed better acute and long-term benefits with participants experiencing a 3.5 centimetre decrease in knee circumference, 24 point improvement in the womac pain and functionality scale, and a four repetition increase in physical functionality. conclusion: the findings suggest that lllt is a viable tool for managing koa when used in conjunction with physical exercise. keywords: photobiomodulation, physical therapy, degenerative joint disease 80 p24: altered thoracic spine kinematics as a potential cause of low back pain in rotationalsport athletes: a case study dimitrije kovac1, ranel venter2 1 fitness medico, belgrade, serbia, 2 department of sport science, stellenbosch university, south africa presenting author e-mail address: dmtrjkovac888@gmail.com introduction: it has been proposed that an excessive, compensatory, motions of the lumbar vertebrae, often caused by limited mobility of the thoracic vertebral segments, can induce low back pain (lbp). such altered kinematics in rotational sports (i.e. tennis, golf and baseball), may explain the high prevalence of low back pain in this athletic population. methods: we report the case of an 18-years old male tennis player (height 180cm, weight 69 kg, right-handed) with lbp affecting sport performance. the patient reported a six-month lasting lbp which compelled him to stop training and playing matches several times. he was treated with different modalities of electrotherapy, ultrasound, manual mobilization and manipulation to the lumbar spine, massage and stretching with only temporary relief of symptoms. he was not able to compete on his previous level without symptoms. magnetic resonance imaging (mri) of the lumbar spines showed no pathological signs. a functional examination with the seated rotation test (bar in front of body) was done. the patient was seated, with hips and knees flexed to 90° and a foam roller placed between the knees to minimize motion of the lower extremities and lumbar spine during thoracic rotation. a 100 cm-iong, 2-cm-diameter wooden stick, placed on chest, was used to standardize the position of the upper extremity. the patient was then asked to rotate his trunk to each side. a 0-3 grading scale from the nine test screening battery firstly described by frohm et al. (2012) was used. if the stick did not reach patient’s knee on both sides, a score of 1 was given bilaterally. if the bar was in line with the knee, the score for that side would be 2. if the bar was in line with the ball the score of 3 would be given. high intertester (0.87) and intratester (0.87) reliability was previously reported for the test. two exercises („rib-grab rotation“, „t-spine rotation with reach“) that focused specifically on thoracic spinal rotation were added to his regular strength and conditioning programme. the exercises were done bilaterally with 3 sets of 6 repetitions. stabilization of the lumbar spine was emphasized during thoracic rotations. during the intervention period the player was allowed participate in some tennis sessions without provoking symptoms. results and conclusion: following the six-week intervention period, a significant improvement in thoracic spine rotation was noted with a score of 3 for both sides on the seated rotation test. the patient also reported significant reduction in pain and he was able to return to high level of training and competition. six months later, the patient maintained the same level of thoracic spine rotation and reported a complete reduction in symptoms. 81 p25: a five year clinical audit of concussive injuries in collegiate male rugby playersa stellenbosch university experience. l. kunorozva1,3, j. c. brown1,3, p. l. viviers2,3 and e. w. derman1,3 1institute of sport and exercise medicine, division of orthopaedics, faculty of health sciences, stellenbosch university, stellenbosch, south africa 2campus health service, stellenbosch university, stellenbosch, south africa 3ioc research centre, south africa presenting author email address: 23484608@sun.ac.za background: sports-related concussion (src) is a common injury occurring mostly in contact sports. more specifically, src is a salient health concern for male collegiate rugby athletes because at least one concussion is reported in every two games. thus, a regular clinical audit of concussive head injuries is warranted in order to provide objective data pertaining to the injury so that pattern recognition can be studied. aims: the purpose of this study was to clinically analyze and report on the concussion rate and symptom patterns from concussive head injuries in collegiate male rugby players for the period 2013-2018. methods: a retrospective analysis of head injuries in a cohort of stellenbosch university collegiate male rugby players (n=367), age (mean±sd; 24.6±4.3), height (mean±sd; 1.83±0.07), weight (mean±sd; 90.7±14.4) and bmi (mean±sd; 26.5±5.7). each of the players with a suspected concussion returned for a clinical assessment performed using the sports concussion assessment tool (scat)-3 (n=252) and/or scat-5 (n=45). the scat questionnaire evaluates both cognitive and physical symptoms based on a scale of 0-6, where 0 indicates the absence of symptoms, while 6 indicates the highest severity. the symptoms and symptom scores are added to give a symptom (of 22) and severity (of 132) scores, respectively. results: the concussion incidence rate was 7.3% of total registered athletes per year representing 87 concussions per year. of the reported symptoms, headaches (57.1%) and pressure in head (55.8%) were the most frequently reported with sadness (12.7%) the least reported. the third scat mean symptom (3.2/22) and severity (5.7/132) scores were comparable to the sixth scat mean symptom (2.3/22) and severity (2.5/132) scores post injury. thirty percent of the 434 head injuries had no scat information. conclusion: the results of this study indicate i) on average 87 concussions per year were treated by the medical staff; ii) headache and pressure in head are the most common presenting symptoms associated with concussion in collegiate rugby players and iii) these findings provide valuable information for planning purposes as well as players education. 82 p26: creating an evidence-based decision-making algorithm for the individualised and holistic management patellofemoral pain. dr dominique leibbrandt, prof quinette louw division of physiotherapy, department of health and rehabilitation sciences, stellenbosch university presenting author e-mail address: domleibbrandt@gmail.com introduction: patellofemoral pain (pfp) is a multifactorial condition with unknown aetiology. recent studies have suggested that there are subgroups of individuals with pfp who present differently and respond differently to treatment. therefore, the purpose of this presentation is to use the best available evidence on risk factors for patellofemoral pain to create a holistic decision-making clinical algorithm that provides recommendations for the most important components to consider for the individualised management of the condition. methods: a search was conducted in pubmed, scopus and science direct for all systematic reviews investigating risk factors or contributing factors for patellofemoral pain. using these reviews, the different categories of risk factors were identified, and the factors supported by the evidence were extracted. this was then used to create an algorithm for clinicians to use to screen for risk factors that they should consider first in treatment. the algorithm also includes treatment options that can be used to address the specific factors that individuals with pfp may present with. this algorithm can be used as a guideline to assist clinicians with treatment planning and individualised management. results and conclusion: six systematic reviews were included. the risk factors associated with pfp include biomechanical risk factors during walking, running and squatting; muscle strength; body mass index and psychological risk factors. sub-groups of subjects with patellofemoral pain include adults, females, military recruits, recreational runners and adolescents. an individualised approach to assessment and treatment is needed for the management of pfp. treatment recommendations should consider different subgroups of individuals with pfp as the risk factors are different amongst sub-groups. future research should incorporate expert opinion of clinicians for the management of pfp as this will improve our understanding of what works and unable us to identify factors that could be important but aren’t currently identified due to a lack of evidence 83 p27: experiences of young south african gymnasts, parents and coaches about the health benefits of sport participation lucas, wc1,2, titus, s3 and young, mem1 1department of sport, recreation and exercise science, university of the western cape, cape town, south africa. 2alcohol, tobacco and other drugs research unit, south african medical research council, cape town, south africa. e-mail: warren.lucas@mrc.ac.za 3interdisciplinary teaching and learning unit, school of public health, university of the western cape, cape town, south africa. introduction: gymnastics, as a physical activity, presents young people with opportunities to learn physical skills, improve eye-hand coordination, develop gross and fine motor skills, and socially develop through engagement with other young people. an understanding of aerobic and anaerobic physical activities is important to enhance young people’s physical, emotional, cognitive and social development. methods: this study investigated the perceptions of a purposively sampled group of young people in the western cape of south africa about the health benefits of gymnastics participation, and reported findings from the perspectives of registered competitive gymnasts, gymnastics coaches, and parents of gymnasts (total n=34), with specific reference to the domains of physical, cognitive and socio-emotional development. a qualitative approach based on the process-person-context-time (ppct) concept, adapted from the bioecological model, was used as the theoretical framework to underpin, analyze and interpret findings of the study. four key informant interviews were conducted with four coaches, and five focus group discussions were held with gymnasts, parents of gymnasts and gymnastics coaches. results: thematic analysis of the participants’ responses indicated the following themes as health benefits and opportunities for children’s development through gymnastics participation: socio-emotional development with respect to positive attitude shifts, respect of peers and coaches, and physical development concerning musculoskeletal growth. conclusion: development of strength and flexibility were also found to be positive contributors to child development. additionally, improvements in cognition which could positively influence children’s academic achievement and the learning of new movement skills, were also attributed to gymnastics participation. the implications of the findings for children’s holistic development was discussed. keywords: gymnastics, parents, coaches, sport participation, physical, cognitive and socioemotional benefits. 84 p28: the epidemiology of iliotibial band friction syndrome (itbfs), and risk factors associated with itbfs, in 21.1km and 56km distance runners fhulufhelo madzhiga1, a jansen van rensburg1, martin p. schwellnus1,2, dina c (christa) janse van rensburg1, sonja swanevelder4, esme jordaan4,5 presenting author e-mail address: madzhigaf@mweb.co.za 1 sport exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 2 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa 3 international olympic committee (ioc) research centre, south africa 4 biostatistics unit, medical research council, parow, south africa 5 statistics and population studies department, university of the western cape introduction: iliotibial band friction syndrome (itbfs) is the most common overuse injury affecting the lateral aspect of the knee in distance runners. novel factors such as medical conditions and medication use are related to other overuse injuries in runners, however, there is limited data on their link to itbfs. the aim of this study was to identify the risk factors associated with itbfs in distance runners. methods: participants (n=12 659) in the two oceans races (21.1km, and 56km) completed a pre‐race medical history screening tool including: training, cardiovascular disease (cvd), risk factors for, and symptoms of cvd, history of diseases affecting major organ systems, cancer, allergies, medication use, and running injury. runners were grouped as having a past history of itbfs (hitbfs group n=509) and a control group (n=12 150). results: independent risk factors associated with a higher risk of a history of iliotibial band friction syndrome (hitbfs) compared to runners with no history of these factors were as follows: any risk factors for cvd (pr=1.5; p=0.0002); any respiratory disease (pr=1.5; p=0.0004); any endocrine disease (pr=1.7;p=0.012); any git disease (pr=2.7; p<0.0001); any nervous system psychiatric disease (pr=1.8; p=0.005); a history of any allergies (pr=1.7; p<0.0001); the use of any analgesic anti‐inflammatory medication (aaim) during a race or in the week before a race (pr=5.8; p<0.0001) and intermediate category of runners (pr=1.4; 95%ci: 1.1‐ 1.8). conclusion: novel independent risk factors associated with itbfs in long distance runners were participation in running for <3 years, being an average runner, having any risk factor for cvd, having a history of disease (i.e. respiratory, endocrine, git, central nervous system cns), allergies and the use of aaim medication a week prior to the race. future longitudinal research is needed to assess the cause effect of these risk factors during distance running and for developing preventative strategies. 85 p29: the development of the c.r.e.s.t anti-doping protocol thanujj kisten, rowena naidoo discipline of biokinetics, exercise and leisure sciences, university of kwa-zulu natal, westville campus, south africa presenting author email address: travinok@gmail.com introduction: the purpose of this study is to develop an anti-doping protocol to promote positive behaviour change in u-17 soccer players. the protocol is guided by the chaos theory. this theory provides a valid framework when studying behaviour change. the theory purports that behaviour change occurs in quantum leaps and is not in a linear, deterministic process. hence, the development of the protocol required different components to allow for different starting points. methods: this study employed a qualitative research approach with focus group discussions. experts in the field of sport psychology, physics, value-based education, anti-doping education and sports science were identified to contribute in the development of the protocol. knowledge from the various experts were integrated, together with literature in the field of anti-doping protocols/interventions, were used to develop the anti-doping protocol. results: the following five components for an anti-doping protocol were developed; coping techniques (c), relaxation techniques (r), education (e), skills (s), training (t) c.r.e.s.t. each component comprised the following activities; coping (various activities were recommended, specifically activities that involved humour), relaxation (breathing exercises, yoga and imagery), education (the south african institute for drug-free sports (saids) educational material, skills (sport specific skills), and training (physical fitness activities). each c.r.e.s.t session will be 60 minutes with approximately 12 minutes per component. each of these components are independent, but inter-dependent on one another. conclusions: in order to determine whether the protocol has an impact on behaviour change, it will be tested in future intervention studies. to test the validity of the chaos theory, the c.r.e.s.t protocol will be implemented, beginning at the various starting points, i.e. with a different component. this anti-doping protocol will be the first of its kind. additionally, the use of the chaos theory is an innovative, yet complex method to promote behaviour, but since behaviour change is a complex process, this theory deems appropriate. 86 p30: research on the supply of public sports service in chinese sports parks wei qian college of physical education, soochow university, 2. no.50 donghuan road,suz hou215021, jiangsu province, p.rchina. 1241802748@qq.com purpose: sports park is a kind of modern city park combining sports functions. it integrates sports and fitness venues and ecological environment to create healthy, athletic and recreational park green space. china now has a sports population of 300 million, and there is a great demand for sports. as the carrier of public sports services, sports park provides venues, facilities and services for citizens' sports. this paper takes the public sports service in chinese sports parks as the research object, studies the supply problem existing in the public sports service, hopes to promote the efficiency of public services in sports parks, improve the participation of citizens in sports, provide suggestions for the future development of chinese sports parks. methods: this paper uses literature, questionnaire, interview and case study. relevant literature was retrieved through cnkj, china sports information network and other information platforms. three sports parks were randomly selected for case study. field interviews were conducted with park managers. questionnaires were made and distributed to 300 citizens who participated in exercise in sports parks to investigate the supply subjects, supply financing, service types and supply management of sports parks. results: the service items in the sports park are mainly outdoor fitness track and traditional ball games, with a single form. lack of indoor stadiums and recreational sports. the capital supply for park construction and development is mainly from the government, the financing channels are single. the park has a low timeliness in the maintenance and protection of the site facilities, and lacks solutions to sudden injury accidents. there is no sports guidance service and no sports guidance staff in the park. sports activities held in the park are insufficient in number and small in scale. insufficient publicity for the park, lacking of publicity on the internet and television. conclusion: the public sports service supply of china's sports parks is single in content, lacking of venues and facilities, no special guidance personnel and insufficient publicity. 87 p31: the epidemiology of muscle and tendon injuries during the super rugby tournament (2013 to 2015) hashendra ramjee1, a jansen van rensburg1, martin p. schwellnus1,2,3, dina c (christa) janse van rensburg1, charl janse van rensburg4, esme jordaan4,5 presenting author e-mail address: h_ramjee@yahoo.com 1 sport exercise medicine and lifestyle institute (semli) and section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 2 emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa 3 international olympic committee (ioc) research centre, south africa 4 biostatistics unit, medical research council, parow, south africa 5 statistics and population studies department, university of the western cape introduction: rugby union is a high-intensity, contact sport and is therefore associated with significant injuries. muscle and tendon injuries form a major proportion of these injuries. the aim of this study was to determine the epidemiology of muscle / musculotendinous (m/mt) injuries amongst elite rugby players over a three-year period (2013 2015) of the annual super rugby tournament. methods: elite male south african rugby players (n= 594) that participated in the annual super rugby competition, for a period of 3 years. data collected daily by each team physician during the tournament period, included injuries sustained in training or match-play. results: a total of 51 952 player-hours were monitored over the 3 year period (4 620 match player-hours; 47 333 training player-hours). in total 578 injuries were documented, of which 278 were m/mt injuries (48%) sustained during this period. m/mt injuries accounted for the majority of tissue-type injuries overall, and were more frequent during match-play (ir 51.9/1000 match player-hours (95% ci 45.6 59.0) compared to training, over the 3 years of the tournament. the incidence rate of m/mt injuries during match-play for 2013 (68.4/1000 playerhours; 95% ci 55.9 82.9) was significantly higher (p<0.05) than in 2014 (35.8/1000 playerhours; 95% ci 26.8 46.8) and 2015 (51.2/1000 player-hours; 95% ci 40.8 63.5). the most common anatomical site for m/mt injuries is the lower limb, with the mechanism of m/mt injury mostly contact related (tackle). m/mt injury incidence rate is also greater in back player positions when compared to forward positions. severity of m/mt injuries from a ‘time-loss’ perspective were mostly minimal (2-3 days). conclusion: the results of this study confirm that m/mt injuries form a significant part of the injury burden in south african teams during the annual super rugby tournament. most m/mt injuries occur during match-play. 88 p32: race distance, history of chronic disease and allergies are risk factors associated with overuse injuries in trail runners: a safer study in 2824 entrants nicola sewry1,2, carel viljoen 3, martin schwellnus 1,2,4, sonja swanevelder 5, esme jordaan 5,6 1sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa, 2international olympic committee (ioc) research centre, south africa, 3sport, exercise medicine and lifestyle institute (semli) and department of physiotherapy, faculty of health sciences, university of pretoria, south africa, 4emeritus professor of sport and exercise medicine, faculty of health sciences, university of cape town, south africa, 5biostatistics unit, south african medical research council, 6statistics and population studies department, university of the western cape, south africa presenting author e-mail address: nicolasewry@hotmail.com introduction: trail runners are an emerging and growing population in the running community, but there are minimal data on the epidemiology and risk factors associated with overuse injuries. the purpose of this study is to determine the risk factors associated with overuse injuries in shorter distance trail runners entering a mass community-based trail running event over a 4-year period. methods: in this cross sectional study, 2824 consenting race entrants from the two oceans trail runs (2012-2015, 10km and 22km) completed an online pre-race medical screening questionnaire. entrants were grouped as having a past (in last 12 months) history of an overuse injury (n=383, with 395 injuries) and a non-injured control group (n=2441) 8 entrants were excluded, based on missing data. the following risk factors associated with injuries investigated were: demographics, running training/racing history, history of main categories of chronic disease, regular use of medications. a multi-variate model was adjusted for age and gender, and prevalence ratios (pr) and p-values are reported. results: sex, age categories or training / racing history were not related to overuse injury risk. independent risk factors that were associated with a higher pr of previous injury were: 1) longer trail run distance (short vs long, pr=0.6; p<0.001), risk factors for cvd (yes vs no, pr=1.6; p=0.0001), history of allergies (yes vs no, pr=1.8; p<0.0001). conclusions: we show that longer race distance, a history of chronic disease and allergies are independent risk factors associated with self-reported overuse injuries in trail runners. these risk factors can influence future injury prevention and management strategies. 89 p33: the effect of robotic walking and activity-based rehabilitation on secondary complications in individuals with spinal cord injury claire shackleton1, robert evans1, sacha west 2; wayne derman3 and yumna albertus1 1division of exercise science and sports medicine, department of human biology, faculty of health science, university of cape town, cape town, western cape, south africa 2department of sports management, cape peninsula university of technology, cape town, western cape, south africa presenting author email address: claireshackleton13@gmail.com introduction: individuals with spinal cord injuries (sci) are at high risk for a multitude of secondary health complications. gold standard activity-based training (abt) and novel robotic locomotor training (rlt) show promising results for reducing secondary complications. however, there is a need for increased evidence through large-scale trials. we thus aimed to evaluate the effects of rlt and abt on secondary complications in individuals with sci. methods: sixteen participants aged 19 – 60 years (mean ± sd: 38.4±14.3), with chronic (>1 year) traumatic motor incomplete sci (c1-c8; asia c-d) were randomized into two intervention groups; rlt and abt groups (control). each intervention involved 60-minute sessions, 3x per week, over 24-weeks. rlt involved solely walking in the ekso bionic suit. abt involved a variety of physical exercises with regular weight bearing in the standing position. outcome measures included pain and spasticity, bladder and bowel function, and quality of life (qol). statistical analysis included repeated measures analysis of variance. a p-value of < 0.05 was considered as statistically significant. results: pain interference with mood (mean difference = -1.56; 95% ci [-2.92 to -0.20]) and day-to-day activities (mean difference = -2.18; 95% ci, [-4.06 to -0.30]) increased across the interventions (p = 0.014). no change in number of pain areas or the intensity of that pain. the shoulder was the most frequent area of pain complaint, followed by the neck and lower back. no changes in total spasticity or bladder and bowel were reported. qol increased (mean difference 3.68; 95% ci, [-6.21 to -1.15]) across the intervention for both groups (p = 0.003). conclusion: although the interventions did not show positive effects on pain and spasticity, qol improved across the 24-weeks for both groups. thus, the long-term psychological benefit of these rehabilitation interventions is promising. 90 p34: the association between the mechanism of injury and the visual mri pathology of acl injuries org strauss1, dina c (christa) janse van rensburg2, mark velleman3, lizelle fletcher4, audrey jansen van rensburg2, catharina c. grant2 presenting author e-mail address: orgstrauss@yahoo.com 1 diagnostic radiology, university of pretoria, south africa; 2 section sports medicine, faculty of health sciences, university of pretoria, pretoria, south africa 3 little company of mary medical centre, pretoria, south africa 4 department of statistics, faculty of natural and agricultural sciences, university of pretoria, pretoria, south africa. introduction: anterior cruciate ligament (acl) injuries are common among athletes and the general public, and may lead to significant absence from activity with an associated financial and social burden. no definitive association has been described between mechanism of injury and pathology, to implement preventative measures to limit these injuries. the aim of this study was to determine whether an association between the mechanism of injury and pathology seen on a magnetic resonance imaging (mri) scan in acl injuries, exists. methods: a cross-sectional analytical study of 87 male patients with acl injury, who had an mri knee scan within the last two years. participants were contacted for consent. the mechanism of injury and pathology seen on the mri scan was noted and categorised into different injury and associated pathology groups. results: mri scans of acl injuries indicated the mechanism of a solid foot plant with rotation of the knee has a greater tendency to be associated with medial meniscal injuries (77%), and also a 54% possibility to be associated with lateral meniscal injuries. a solid foot plant with a valgus stress on the knee showed a higher incidence of associated medial collateral ligaments (mcl) injuries (41%) and femoral bone bruising (62 %). these two mechanisms of injury are the most common in acl injuries and contribute to the clinical significance found. results was however not statistically significant (p=0.44, chi-square value=20.27, df=45) for any association between pathology and mechanism of injury. conclusion: some injury mechanisms causing acl injury were more common than others and also had more associated pathology. the most common mechanism of injury noted is a solid foot plant with either rotation of the knee or valgus stress on the knee. strengthening tissue structures involved in those movement patterns that cause these mechanisms can possibly limit acl injuries in athletes and the general public. 91 p35: work and family support among participants in the world transplant games prof johan van heerden university of kwazulu-natal purpose: to conduct an analysis of work and family support systems among participants in the transplant games. methods: the design comprised an analytical survey among participants (n=60) taking part in the 19th world transplant games, held in durban, south africa. work and family support were measured respectively, using the modified work apgar (adaptation, partnership, growth, affection, resolve) and the smilkstein’s family system apgar questionnaires. results and conclusion: there was a greater prevalence of liver and kidney transplants than any other organ. apgar scores showed high functionality. females were more functional with regards to work and family support (p>0.05). kidney transplant recipients had greater functionality in the work place; however, liver transplant recipients had a greater functionality with regards to family support (p<0.05). participants waiting more than two years for a transplant showed greater functionality with regards to work and family support (p>0.05). in conclusion this study provides additional information with regards to work and family support systems and their functionality among transplant recipients who are physically active. 92 p36: prevalence and type of injuries in south african trail runners harry van wyk, steyn swart, and susan h bassett department of sport, recreation and exercise science, university of the western cape, cape town, south africa introduction: trail running is becoming an ever more popular sport worldwide with the trail running population having more than doubled since 2006. more and more people are moving from the monotonous and repetitive running nature of road running to the trails. with the popularity of trail running increasing, so are the number of injuries being reported. injuries range from acute to chronic and include muscular, skeletal, ligamentous and tendinous. the amount of time an athlete cannot train or compete due to injury depends on its severity. this study aims to investigate the prevalence and type of injuries of trail runners in south african trail runners aged between 19-40 years. methods: this study will employ a descriptive, survey research design involving the use of a questionnaire sent to various trail running groups or clubs, which will be used to collect specific data from the runners. the sample will include male and female trail runners from the ages of 19-40 years from both recreational to elite level, who have at least 2 years of running experience. an information sheet, explaining the study and what the participant will be asked to do, will be sent via email to various trail running groups and clubs across the country to distribute to their members. participation will be purely voluntary and a link will be provided, via the running club, to the google form questionnaire. by completing the questionnaire, consent will be implied. the sample size is dependent on the amount of respondents. descriptive statistics will be utilized to analyse the data. in doing so, the type of injury and prevalence thereof will be established. results: this study data has not be collected yet, but we aim to do this by september this year, so the study will be complete in time for presentation at the conference in october. case report 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license changes in cardiorespiratory fitness and cardiovascular health in the workplace: a case study g torres, b phys ed, bspsc (hons), msc med, phd ,cscs; pj gradidge, bspsc, bspsc (hons), msc med, phd; d constantinou, mbbch, bsc(med)hons, msc med, mphil, ffims, facsm centre for exercise science and sports medicine, faculty of health sciences, university of the witwatersrand, johannesburg, south africa corresponding author: g torres (georgia.torres@wits.ac.za) workplace wellness programmes have been given increasing attention as a means to improve employee health and lower health costs [1]. most wellness programmes measure and report on cardiovascular (cv) risk factors, such as nutrition, smoking cessation, weight loss, and stress management. cardiorespiratory fitness (crf), an indicator of physical health-related fitness, has been identified as an independent predictor of cv and all-cause mortality and is also the risk factor with the highest percentage to all-cause deaths when compared to other traditional risk factors [2]. however, crf is not measured or tracked for change during workplace wellness programmes, suggesting that employers are not completely aware of the employee’s cv health. employers therefore need to be made aware of the cardioprotective benefits of physical activity and the importance of including crf measurement in workplace wellness programmes. this case study demonstrates the effectiveness of a supervised and monitored exercise intervention programme on crf, cv health and medical health claims of a high-risk employee of a corporate company. case report history a 49-year-old male employee presented with hypertension, obesity and depression. table 1 outlines the baseline data of the participant. he was on anti-hypertensive and antidepression medications and had been sedentary (not engaged in moderate-vigorous intensity physical activity for at least three days/week for three months). he decided to join an exercise facility at work to improve his health. physical examination an initial assessment included pre-participation exercise safety screening and the determination of cv risk factors using the diagnostic criteria published by the american college of sports medicine (acsm) [3]. height (cm) and mass (kg) were measured using the detecto stadiometer (usa) and tanita body composition scale (bf-350, tokyo) respectively. the body mass index (bmi) was calculated in kg.m2. blood pressure (mmhg) was measured three times, consecutively, in a seated, rested position with a rossmax international (taiwan) electronic blood pressure cuff, using a standardised method. the average of the two latter measures was used. waist circumference (cm) was measured at the greatest abdominal circumference between the lowest rib and the iliac crests. point-of-care fasting, full lipogram and blood glucose tests were conducted using standardised protocols. crf was measured as vo2peak using the technogym® (tg) submaximal test on a tg treadmill. this test estimates maximal oxygen consumption (vo2peak) using the linear relationship between heart rate and vo2 max without subjecting the individual to high levels of physical stress. during the tg submaximal exercise testing, predetermined workloads are used to elicit a steady state of exertion (plateau in heart rate and vo2). the steady state heart rate at each workload is then calculated and extrapolated to the vo2 at the age-predicted maximal heart rate. this test is a double stage submaximal test and its validity and reliability has been documented [4]. medical health claims were provided by the participant for three months before, during and after the exercise intervention programme. intervention the exercise intervention programme was administered in the exercise facility and was part of a corporate wellness programme at the participant’s workplace. the participant was assigned an individualised 12-week exercise programme, designed on the mywellness® technogym® cloud platform, background: cardiorespiratory fitness (crf) is an independent predictor of cardiovascular (cv) and all-cause mortality, contributing a higher proportion of cv risk compared to other traditionally recognised risk factors. however, crf is not included in usual workplace wellness protocols and, as such, employers are not aware of the importance of this factor. aim: the aim of this case study was to explore the effect of a 12-week exercise intervention programme on crf, cv health and medical health claims in a male participant who was employed by a corporate company with existing chronic diseases. findings: health outcome measures improved after the 12-week exercise intervention programme. crf showed the greatest improvement and medical health claims were lowered during the three-month post-intervention period. implications: crf should be included as a health outcome measure in worksite wellness programmes and monitored. keywords: cardiopulmonary fitness, exercise interventions, medical health claims, corporate wellness s afr j sports med 2020; 32:1-4. doi: 10.17159/2078-516x/2020/v32i1a7638 https://orcid.org/0000-0002-0197-4718 https://orcid.org/0000-0001-5225-1184 https://orcid.org/0000-0002-3363-7695 http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7638 case report sajsm vol. 32 no. 1 2020 2 and based on the american college of sports medicine’s (acsm) guidelines for exercise testing and prescription regarding hypertension [3]. the participant could access the programme on the mobile application of the mywellness® technogym® cloud. the online cloud platform allows for realtime exercise data to be collected from the exercise equipment and third-party connected devices. thus all exercise/physical activity data (in and outside the exercise facility) of the participant were collected during the intervention period. a biokineticist (exercise rehabilitation specialist) supervised these individual exercise sessions and monitored any physiological changes using the tg mywellness® cloud. the exercise programme was adjusted according to the participant’s blood pressure, heart rate and adaptation to the exercise routine. each contact session was also used to motivate the participant. the assigned weekly exercise volume was used as the intervention’s primary goal. the biokineticist provided verbal motivation to the participant on achieving this goal and attending the sessions. after the 12-week postassessment, the biokineticist discussed the results and health outcomes with the participant. fig. 1. medical health claims per week. the data are presented from november, week one 2017 to july, week one 2018. the exercise intervention took place between weeks 12 and 24. 0 4 8 12 16 20 24 28 32 36 40 0 1000 2000 3000 4000 weeks exercise intervention nov 2017 july 2018 m e d ic a l h e a lt h c la im s p e r w e e k ( r a n d ) table 1. changes in physical characteristics and physiological and cardiometabolic parameters parameters baseline follow-up % change absolute change age (yrs) 49 49 0 0 resting heart rate (bt.min-1) 85 78 -8 -7 height (cm) 174 174 0 0 weight (kg) 99 100 1 +0.8 bmi (kg.m2) 32.7 33 1 +0.3 waist circumference (cm) 111 110 -1 -1 systolic blood pressure (mmhg) 149 139 -7 -10 diastolic blood pressure (mmhg) 108 99 -8 -9 total cholesterol (mmol.l-1) 2.59 2.73 5 +0.14 low density lipoproteins (mmol.l-1) 1.05 0.98 -7 -0.07 triglycerides (mmol.l-1) 3.31 2.18 -34 -1.13 high density lipoproteins (mmol.l-1) 0.88 1 14 +0.12 glucose (mmol.l-1) 4.3 4.5 5 +0.2 peak vo2 (ml.kg-1min-1) 25.2 42.3 68 +17.1 weekly physical activity level (kcal.kg-1wk-1) 0 19.4 n/a +19.4 cardiovascular (cv) risk factors* age 1 1++ family 1 1++ smoking 0 0++ inactivity 1 0† hypertension 1 1++ dyslipidaemia 1 0† obesity 1 1++ prediabetes 0 0++ total number of cv risk factors 6 4 *0, cv risk factor absent; *1, cv risk factor present; †, cv risk factor improved; ++, cv risk factor did not change. bmi= weight (kg)/height2 (m) case report 3 sajsm vol. 32 no. 1 2020 results and outcomes the measurements of resting heart rate, waist circumference, systolic and diastolic blood pressures, and peak vo2 improved at follow-up (table 1). weight and bmi increased slightly. triglycerides, low-density lipoprotein cholesterol, and highdensity lipoprotein cholesterol improved post-intervention, while total cholesterol and blood glucose increased slightly and remained within healthy ranges. the number of cv risk factors decreased from six at baseline to four at follow-up. it should be noted that of the six modifiable risk factors (smoking, inactivity, hypertension, dyslipidaemia, obesity, prediabetes), the number halved from four to two. total medical health claims for the three months preintervention equalled r7 199 (zar). this value went up to r9 076 during the intervention and then was reduced to r4 558, three-months post-intervention (fig. 1). the total medical health costs were reduced by 37% from preintervention to three-months post-intervention. a more comprehensive account of medical healthcare costs was not provided. discussion the exercise intervention programme improved the health outcomes of this participant and reduced the number of cv risk factors (table 1). weight and bmi did not improve; however, waist circumference decreased slightly. the improvement in high-density lipoprotein cholesterol is encouraging as this is a negative cv risk factor that is beneficial to cv health. the greatest change occurred with crf (vo2 peak) that improved by 68%, despite no weight loss. the health outcomes of this case study agree with other published research of workplace wellness programmes [1]. these studies though have not reported on changes in crf. crf has been identified as an independent predictor of cv and all-cause mortality. this is also the risk factor that attributes the highest percentage to all-cause deaths when compared to other traditional risk factors [2]. furthermore, the american heart association recently proposed a case for crf as a clinical vital sign [5]. therefore, workplace wellness programmes should place an importance on measuring, tracking and improving crf via exercise interventions. as previously mentioned, in this case study there was an improvement in crf following supervised exercise intervention. there is also a lack in research accurately reporting on the specifics of the exercise prescription used in exercise interventions (e.g. exercise intensity or weekly volume) within corporate wellness programmes and especially for the treatment and prevention of chronic diseases. this case study focused on monitoring and recording the participant’s exercise and physical activity sessions. the participant expended an average weekly exercise volume of 19 kcal.kg1week-1 during the intervention phase. this volume agrees with the recommended dose from the current physical activity guidelines. ding et al. [6] also showed the importance of targeting sedentary behaviour within the spectrum of lifestyle risk behaviours in reducing all-cause mortality. crf is a simple method for monitoring the transition from a state of being sedentary to becoming completely aligned with the target of 150 moderate-vigorous physical activity minutes per week for the prevention of cv disease. an interesting finding in this case-study is that the medical health claims increased during the intervention period and reduced in the post-intervention period to levels below those of the pre-intervention period. this finding could be confounded by other factors, such as change in medical claim behaviour during the fiscal year, or expenses unrelated to the presenting chronic condition and would require further investigation. nevertheless, the data suggest a spillover effect of exercise to lower healthcare claims following supervised exercise. in addition, the participant decided to continue being physically active despite exiting the supervised exercise intervention(data on the mywellness® technogym® cloud platform confirmed this). the intervention programme may have played a role in motivating the employee to continue being physically active. the motivational aspect of an exercise intervention programme is noteworthy. a limitation of the case study is the restricted data on specific healthcare claims and the pattern of claims prior to entry into the exercise intervention programme. further research is needed using randomised control trials to determine the longitudinal patterns of healthcare claims and other outcomes, such as illness-related absenteeism, in employed individuals with single and multiple chronic conditions. conclusion this exercise intervention programme had beneficial effects on the crf, health and medical health claims profile of the employee. the greatest change occurred in crf, supporting the need for including the assessment and monitoring of this factor in corporate wellness programmes. author contributions gt: conception, design, analysis, interpretation of data and writing of paper. pg: critical revision of manuscript content, writing of manuscript and approval of the version to be published. dc: critical revision of manuscript content, writing of manuscript and approval of the version to be published. references 1. lutz n, taeymans j, ballmer c, et al. cost-effectiveness and costbenefit of worksite health promotion programmes in europe: a systematic review. eur j public health 2019; 29(3):540-546. [doi:10.1093/eurpub/cky269] 2. myers j, mcauley p, lavie cj, et al. physical activity and cardiorespiratory fitness as major markers of cardiovascular risk: their independent and interwoven importance to health status. prog cardiovasc dis 2014; 57(4):306-314. [doi: 10.1016/j.pcad.2014.09.011] 3. acsm’s guidelines for exercise testing and prescription. 10th ed., 2016. philadelphia, wouters kluwer. chapter 2; 48, chapter 10. 4. cecchinelli f, senni s, paolo b. physical assessment with technogym fitness equipment. technogym medical-scientific research department. the 15th sports medicine balkan congress, medicina sportiva 2008; 14. case report sajsm vol. 32 no. 1 2020 4 5. ross r, blair sn, arena r, et al. importance of assessing cardiorespiratory fitness in clinical practice: a case for fitness as a clinical vital sign. a scientific statement from the american heart association. circulation 2016; 134(24) :e653–e699.[ doi:10.1161/cir.0000000000000461] 6. ding d, rogers k, van der ploeg h, et al. traditional and emerging lifestyle risk behaviors and all-cause mortality in middle-aged and older adults: evidence from a large population based australian cohort. plos med 2015; 12(12): e1001917. [doi:10.1371/journal.pmed.1001917] j o u r n a l o f t h e s a s p o r t s m e d i c i n e a s s o c i a t i o n 51*01375 itjied ic in ie 5p o r tg i= m = l= 5 k u n d i t y d s k r i f v a n di e s a s p o n e e s k u n d e v e r e n i g i n g •aerobic dance •thought strategies • osteochondritis dissecans • physiotherapy— runners r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) reg. h o j h r. tv5 1 / 2 5 5 w e v a c t 101/1965) in sports in ju ry__ and trauma. ■ clinically well to le ra te d , geigy u c a l l y e f f e c t i v e , n oldtffelmc uiitm 51 ag voltaren gt 50 geigy coated tablets) nts treated worldwide* •statistics o n filer ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) journal of the s. a sports medicine association tydskrif van dies a sportoeneeskundeverenioino editorial comment plaster casting or not? interview comrades — adequate medical care? feature thought strategies of long distance runners pensees some sporting reflections feature aerobic dance injuries ultraman ultraman peaks sasma update sasma news book review drugs and performance in sports physiotherapy column management of long distance runners by physiotherapy review osteochondritis dissecans news editor in chief dr c noble mb bch,fcs(sa) associate editors proftnoakesmbchb.md dr dawie van velden mb chb (stell), m prax med(pretoria) advisory board medicine: dr i cohen mb chb d obst, rcoc orthopaedic traumatology: dr p firer bsc (eng) mb bch (wits) m med (orthoxwits) bric e hugo mb chb, mmed (chir) orthopaedics dr jc usdin mb bch, frcs (edin) cardiology: col dp myburch sm mb chb, facc physical education: hannes botha d phil (phys ed) gynaecology: dr jack adno m b bch (wits) m d (med) dip o&g (wits) front cover. transparency courtesy o f colour library. the journal o f the sa sports medicine association is exclusively sponsored by ciba-geigy (pty) ltd. the journal is produced by commedica po box 3909, rand burg 2125. the views expressed in this publication are those of the authors and not necessarily those of the sponsors or publishers. v s p o rtb e s e rin g s en s p o rt in ju ry an d k a rd io re h a t> ilfta s« 1 c a rd ia c r e h a b ilita tio n p ro g ra m p ro g ra m m e 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 'editorial comment\ plaster casting or not? clive noble mb chb. fcs (sa) laster of paris casting has for many years been syn­ onymous with orthopaed­ ics there was even a say ing usedbythejuniordoctors "when in doubt put it in plaster" certainly today plaster casting isstill an essentialpartoffracturetreatments.lt hasalso been used in a variety of ligamen­ tous injuries all degrees of ligamentous instability have been treated by cast im­ mobilisation. the twojoints particularly involved have been the knee and ankle. the period of immobilisation varied from a few days to many weeks in the light of re­ cent investiga­ tions one has to decide whether plastercastingis really necessary inall ligamentous injuries. there is even a strong opi­ nion that it may bedetrimentalin some cases. as long agoas1966 it was shown that ap proxim ately 80% of ankled ligament injuries got better no m a tte r what form of treat­ ment was given. practical experience has shown us that movements of an injured joint that has been immobilised inacastwilltakeabout twice as long to recoverasan injured joint that has not been immobilised. even today many doctors still immobilise a knee withahaemathrosis. by doing this significant internal derangement may bemissed.thismay lead to failure of ade­ quate and correct treatment. as an ex ampleanavulsed fragment which could have been accurately replaced now smoothsoff and this becomes impossi­ ble. similarly badly torn ligaments which required surgery may be left in a weak­ ened state. contributingfactortothedevelopment of osteoarthritis on the longer side. other workers have not been in agreement hult4 investigating swedish factory wor­ kers found no differences in theincidence of leg length discrepancy in workers com­ plaining of backache. fisk & biagent5 also found thata moderatedegreeof leg length discrepancy played little if any part inthein cidence of backache. in runners leg length discrepancy of even minor nature has been blamed for inju­ ry of back, hip and leg. none of these in­ vestigations had a real scientific basis. subotnich6 has stated that a 1/a inch leg length discrepancy in a runner is more liabletocause injury than a v leg length discrepancyinanon active person. cross'7 investigation of a group of mara­ thon runners found that 49% had leg length discrepancy of 5mm or more. he concluded that his study provided no justification for the routine use of lifts (in theshoe) to equalise smaller amounts of leg length discre­ pancy in runners. he also concluded that runners with struc­ tural discrepancies of 1cm and more can function quite handsomely without any need forequali sation of leg lengths. we obviously need more knowledge wouldn't this be an excellent project for astudent/physiotherapist/doctor?^ references 1. rush w.a, steiner h a , am j. roentgen ra ad ther., 5 6 : 616-6231946. 2. nicholspj.r. brmed. j 1:1863-69 1960 3 cofton j.p trueman ge. canadian medical alloc j. 1 0 4 : 791-799 1971 4. hult l. acta orthop. scand. 24: 30-31 1954 5. fisk j.w. biagent m.c. nz med. j. 8 1 : 477-4801975 6. subotnik sj. ortho soortsphys ther. 3 : 11-161981 7. cross r.h. am j. of sp. med. 1 1 : 121-123 1983. n 0 1,198£1m arch 1988 vo l 3, besides stiffness of the joint resultant muscle weakness may preventthe player from rapidly returning to his sport. re­ injury if he returns to sport too soon, may also occur. there is a growing tendency to only use plastercastingtofracturesandaftersur gery. rapid rehabilitation using physio­ therapy and an intensive exercise pro­ gramme would appear to be the treat­ ment of choice in most sports injuries. leg length discrepencies in the last editorial i mentioned a kinesthesiologist who told most of his patients they had a leg length discrepan­ cy and proceeded to treat them with a yellow page insert in theirshoes. i believe it is more important to assess scientifical­ ly if a leg length discrepancy has sig­ nificance in causing injury especially in marathon runners. in 1946 rush & stainer1 found a higher in cidenceof back pain in army recruits with leg length discrepancy. nichols2 in 1960 found that 22% of airmen complaining of lower back pain had a leg length dis­ crepancy of 12,5mm or more, compared to 7% in a control group. crofton and trueman5 felt that a leg length discre­ pancy v2 inch to 1 inch (2.54cm) was a 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) interview, comrades adequate medical care? ntroduction: s the medical care at the comrades marathon good enough? this has been worrying many runners as well as their doctors for some tim e to answer this query we put a number of questions to dr j. codlonton. vo l 3, n 0 1,1988 d rnoble how many runners do you anticipate taking part in comrades this year dr codlonton it is unlikely to be in excess o f 12 000 runners. d rnoble we believe that an analysis of the collapsed athletes was started in the medical tent last year. what is the objective behind this research? dr codlonton in fact we have been monitoring many parameters over the past 10 years. our main objectives are to attem pt to: * improve the quality o f medical care at the end o f the comrades marathon * provide runners with feedback about problems which occur during the race which would help them to decrease the magnitude o f their problems. drnoble what werethe most common problems encountered in the medical tent last year? dr codlonton the most common problems encoun­ tered are related to dehydration and to heat-stress injury amongst a host o f many other minor injuries. drnoble. what causes these problems? dr codlonton these problems are caused by runners whoarejustuninformedasregardslong distance running and have as a result poor drinking habits: eg. drinking too late drinking too little drinking the wrong kind o f fluids they don't take cognisance o f adverse warning signs o f distress. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) "once again it is up to the runner to determine his own capabilities. possibly the running clubs could encourage their runners to have e.c.c:sdone." which can be obtained from running magazines and running clubs. comrades organisers however will endeavourtocommunicateinformation acquired over the years which would benefit the runners in anyway by way o f articles in jou rn a ls and lectures throughout the country. dr noble do you think that more stringent q u alifyin g regulations should be introduced? drgocjlonton from a medical point o f view, i do think thatmorestringentstandardsshouldbe introduced. it is my belief that many o f the runners have not learn t to run longer distances. more longer distanced races should beintroducedinthiscountry and should be made part o f the qualifying regulations for the comrades drnoble it is suggested that runners could be tested if they were unsureoftheirfitness will this ever take place? drg odlonton unlikely— not by comrades. once again itisuptotherunnertodeterminehisown capabilities. possibly the running clubs could encourage their runners to have ec.cs done. once over the age o f 30 and especially over the age o f 50. dr noble should theorganisershavethepowerto take runners out of the race who are obviously in no fit state to continue? d rc odlonton i would say definitely "yes", but it is not likely that anyone would ever have the authority to do so. drnoble if the ambient temperatures and humidity are too high, should the race not be postponed for one day? d rc odlonton a definite no — i t would be an impossibility to get everyone back again the following day drnoble shouldn't different coloured flags be instituted to warn runners of prevailing heat conditions eg. red flag signifying dangerously hot weather? d rc odlonton yes: a heat-stress m o n itorin g thermometer has been used in thelast three comrades with colour coding warnings. drnoble what contingency plans do you have this year should the number of runners requiring medical attention increase, especially over the 'busy period? drc odlonton we intend to increase the number o f medical staff available proportionate to the number o f entrants for comrades for 1988. secondly the inclement weather may be the cause of many of these problems. drnoble what should runners be doing to avoid these problems? d rc odlonton self education is the most important factor in counter-acting problems a runnershouldhaveknowledgeofhisown capabilities heshould have knowledgeof how much to drink and when. he should take cognisance o f adverse warning signs within himself. he should take cognisance o f the prevailing weather conditions. drnoble how many runners required medical attention in 1987? what percentage was this of the total comrades runners? d rc od lonton 555 runners collapsed in a serious condition in 1987 i.e. were on drips — ±4,8% o f the total number o f runners who participated. drnoble were there adequate medical facilities and medical staff to cope with these runners? d rc odlonton generally, yes, except for a busy stretch when a large concentration o f runners collapsed in a short period o f time ie. at a rate o f one runner every 11 seconds. these runners were how ever all attended to eventually drnoble will comrades organisers launch an education programme at any stage? d rc odlonton it is unlikely as this does not fall within the framework o f the comrades organisers. it is the duty o f the runners themselves to acquire the necessary knowledge, r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) feature thought strategies of long­ distance runners dr hein helco schomer. ba(hons) ma phd lecturer in the department of psychology and guest lecturer in the bsc(med) (hons) sport science course, department of physiology medical school, university of cape town, south africa. r a bstract this study involved the recording o f beginner average and superior marathoner thought ver__________ baiizationsduringtraining sessions o f diverse intensities, the development o f a func­ tional classification system o f the run­ ners' thoughts within the broad associa­ tion/dissociation framework, and the content analysis o f the recorded thought texts the results indicated that proportional increases in the amount o f associative thinkingarerelatedlinearlytoincreases in perceived training intensities, this rela­ tionship holding for all groups o f marathoners. the qualitative differ­ ences within the associative thought patterns o f the superior marathoners, and the im plica tions for op timal psycho­ logical prepara tion in regard to cognitive strategiesduringtrainingarediscussed. introduction sport psychologists have recently begun to focus on the cognitive processes of athletes,speculatingonhowthequality orquantity of theirthoughtsmight con­ tribute to theirexcellent performances. conclusions drawn so far have been clouded over by rather unsystematic ac­ counts of subjective experiences and views. research into the mental strategies adopted by long-distance runners to cope with the immense effort involved incompleting a marathon hastill now re­ lied entirely on preor post-event ques­ tionnaire data (morgan & pollock, 1977; freischlag, 1981; summers, sargent, lev­ ey &murray, 1982; okwumabua, meyers, schleser & cooke, 1983; weinberg, smith, jackson & could, 1984.) nowhere before has the continuous th o u g h t flow o f runners been documented. the aim of this investiga­ tion was to record and analyze instan taneousthought processes of marathon runners during the full length of their training runs and to set up a functional classification system that cou id be used for future manipulations of runners' thoughts. according to morgan and pollock'sd977) associative/dissociative mental strategy classificationwhichhasformedthebasis of most research into the cognitive ac­ tivities of marathoners during long­ distance racing and training, elite marathoners associate, effectively read­ ing their body and modulating pace ac­ cordingly, whereas non-elite runnersdis sociate from any painful, sensory cues. however, as runners have to expose themselves to successive approxima tionsof their relative physiological toler­ ance in order to procure aerobic condi­ tioning (ryder, carr & herget, 1976), as­ sociative cognitive strategiesarenot per­ ceived by the author to be exclusively practised by elite long-distance runners. it is hypothesized that an increase in as sociativethinkingisdirectly related toan increase in training intensity regardless of the running statusof the athlete it is further hypothesized that there will be qualitative differences within the as­ sociative cognitive strategy displayed by marathon runnersof differing running status. method subjects the novice group was made up of 12 highly unfit individuals who had volun­ teered to participates a 7-month moni­ tored training programme leading up to their first marathon. the 10 subjects in the average group had a minimum ex­ perience of two completed marathons and race times between 3 and 4 hours for males and v h and 41/2 hours for females the superior group consisted of 9 high­ ly competitive marathon runners with race times below 3 hours for males and below 31/2 hours for females six of these runners were rated aselite south african marathoners with race times of 2:17,2:17 and 2:23forthemales,and 242,2:52and 2:56 for the females. apparatus a light-weight micro-cassette recorder was carried by the subjects in a specially designed belt around their waist. the borg scale (borg, 1978) enabled the m a r c h 1988 v o l 3, n o 1,1988 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) marathoners to rate theirtraining inten­ sity afteracognitivestrategy recording. procedure subjects were instructed to speak whatever came to their minds during training runs and could utter their thoughts in sentences, phrasesor words strict confidentiality wasassu red. after a cognitive strategy recording the run­ ners were asked to ratetheir level of per ceivedtraining intensity withthehelpof theborg scale. onaverage, every individu­ al carried the recording apparatus four times, the first two recordingsgenerally being regarded as familiarization trials. the transcribed recordings, which omit­ ted the identity of the runner as well as the declared training intensity, weresur veyed for recurrent thoughts on task related and task-unrelated material. ten themecategories were proposed — (1) feelings and affects: thoughts on general sensations of the body, like feel­ ings of vitality or fatigue, with no men­ tion of specific body parts, (2) body monitoring: thoughts with specific men­ tion of anatomy or body physiology, like breathing rhythm and heart beat, (3) command and instruction: emphatic self-regulatory instructions to whole body or specific body parts, (4) pace monitoring: verbalized feedback on cur­ rent running performance with respect totime,distance,andspeedofpacing,(5) environmental feedback: thoughts about the weather, temperature, and noise levels etc, (6) reflective activity: thoughts on pastandfutureissues relat­ ed to training and racing experiences, (7) personal problem solving: issues of an in trapersonaland interpersonal nature in­ cluding reflective introspection and be­ lief system evaluation,(8) work: thoughts spent onjob.workand careeropportuni ties, (9)course information.descriptions about scenery that are of no conse­ quence to pace, (10) talk and conversa­ tional chatter directspeech with other runners, and unintelligible or inconse­ quential, extraneous chit-chat. the most concise intelligible cognitive ex­ pression (sentenceorphrase)that could be understood when isolated was de­ fined as the recording unit and was enumerated by asinglecognitivestrate­ gy category abbreviation. a frequency count of the category abb reviations in a completely content analyzed text was then transformed into percentages of occurrence and raw data tables were compiled. results a kruskal-wallisone-wayanalysisof var­ iance was executed on the associative thoughtcategory data. an insignificant statistical difference was recorded (h=4,581; df = 2; p > 0,05), i.e. thesuperi ormarathonersdid not manifesta preva­ lence for the associative cognitive strate­ gy. a multiple regression model was used in the analysis of the proportions of ac­ tivity time assigned to categories of ac­ tivity. the overall pattern emerging across the analysis was that association gave remarkably strong linear correla­ tions in all analyses within and across the groups of subjects. the analysis showed acleartendency in theratingsof training intensity to be related linearly to the thecorrelationcoefficients lend strong support to the authors contention that regardless of the marathoners running status a high training effort can only be achievedandmaintainedsafelyandeffi ciently by adopting a predominantly as­ sociative cog n iti ve strategy. these find­ ings do not agree with morgan and pol­ lock's (1977) original investigation in specified a c tiv ity com ponent proportions discussion proportional increasesintheamount of associativecognitivestrategygohandin hand with increasesinresultanttraining run effort ratings this relationship holds within and across all the groups of marathoners. theapparentstrengths of which it was concluded that elite marathoners adopted the associative c og n itive s tra te g y due to th e ir phenomenal physical condition, whereas non-world class runners preferred to dis­ sociate from the painful sensorv feed­ back received from their bodies during a race. the hypothesized qualitative differences within associative thinking in relationto march 1988 vo l 3, no 1,1988 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) training intensity are evident as follows: body monitoring showsa substantial ef­ fect on perceived training intensity from an average marathonerstatus upwards, while the role of the general affective feedback diminishes in its relation to per­ ceived training intensity at a high run­ ning status. this statistically significant differenceisthemostdistinctivecharacaccordingly. no "altered states of consciousness" or "runner's high" were reported in thecog nitive strategy recordings, which sup­ ports thesimilarfinding by sacks, milvy, perry and sherman (1981). runners' dis­ sociative thinking appeared goal directed and intentional. the research project concentrated excluof thinking (gilhooly, 1982), thinking is seen as the manipulation of symbols both within working memory and be­ tween long-term and working memon/. the manipulations are understood to conform to rules stored in long-term memory rules selected from long-term memorydependonwhichgoalsarecur rentandonthecontentsoftheworking memon/. this i m plies that the psycholog­ ical side of a runner is as accessible to training as the physiological side as effort ratings advanced, sentence structures and narrations became rudimentary and unadorned. ericsson and simon (1980) stated that the most important condition under which ver­ balization can be expected to be an ac­ curate account of cognitive activity is that the verbal report has to be made concu rrently with the task-related men­ tal activity. according to them,only infor­ mation in focal attention, that is informa­ tion in the w orking m em ory, is "verbalizable". cognitive strategy training, guiding the runner to assimilate, or in thecase of the superiorrunnerfoster.theexactingbody monitoring technique is expected to yield a substantial improvement in the athlete's capacity to heighten his/her training intensity without the risk of in­ jury, and in the long-term enhance his/her aerobic conditioning and race times however, it must be emphasized that psychological training can only be seen to complement the marathoner's present physical capabilities association when practised at high training intensi­ ties may be seen to "fine-tune" physical aptitude by allowing physical skills to be exhibited and extended optimally. references borg,gd978) simple rating methods forestimation o f perceived exertion. in g borg (ed.), physical work and e ffo rt (pp 3947) oxford pergamon press ericsson, k a & simon, h a (1980). verbal reports as data psychological review, 87,215-251 freischlag, i (1981) selected psycho-social charac­ teristics o f marathoners international journal o f sport psychology. 12,282-288 ci i hooly, kj (1982) thinking directed, undirected and creative london academic press morgan, w p (april 1978) the mind o f the marathoner. psychology today, pp 3849 morgan, w.p & pollock, m.l (1977) psychologiccharac terization of theelite distance runner annalsofthe n y academ y o f sciences, 301, 382403 okwum abua.tm , meyers, aw., schleser, r & cooke, c i, (1983) cognitive strategies and running perfor­ mance — an explorative study cognitive therapy and research. 7, 363-369. ryder, h.w, carr, h j. & herget, p (1976) fu ture perfor­ mance in footracing scientific american, 234, 109-119 sacks,m.h,milvy,p,perry,sw & sherman, lr (1981) mental status and psychological coping during a 100 mile race in m.h sacks & m.l sacks (edsj, psychology o f running (pp 166-175) champaign, il human kinetics summers, ±1, sargent, gi, levey, a i & murray, k.d (1982) middle-aged non-elite marathon runners a profile perceptual and motorskills, 54,963-969 weinberg, rs,sm ith,!, jackson, a & gould, d (1984) effect o f association, dissociation and positive self talk strategies on endurance perform ance psycho­ m o to r learning. 9,25-32 m a r c h 1988 v o l 3, n o 1,1988 teristicofthesuperiorrunners'thought profile — specificity through thorough skill practice morgan (1978) suggested that average runners employ dissociation to negoti­ ate a temporary pain zone marathoners in this study preferred to deal with pain or discomfort associatively by talking about the symptoms, instructing them­ selves to relax and by adjusting pace sively on the recording of cognitive strategies during training runs as it is in the training phase thatan athlete has to approximateandconstantlytesthis/her potential for the real event(ryder et al., 1976). experienced runners pointed out that there is very little room for innova­ tion and implementation of untried ideasduringa race itisof interestto note thataccording totheserial modal model 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) some sporting reflections professor t im noakes mb chb md or as long as i can remem­ ber, sport has been an im­ portant component of my life. one of my earliest sporting recollections as an eight or nine year old, was sharing the national humiliationofdevastatingdefeatatthe hands of the touring australian crick­ eters. rugby entered my consciousness at a somewhat later stage, with the visit of the 1960 all blacks and the springbok tour to britain the following year, in or­ der to follow the latter tour and not withoutsome risk, ismuggledasmall ra­ dio into boarding school. like most youngsters with an insecure ego, l recog­ nized that international rugby was war, and that our national superiority was conf i rmed by thesuccess of those south african teams. today i frequently run, swim or cycle with the local survivors of those springbok teams; they remain as heroic to me today as did their exploits heard on that small radio by an impres sionableyouth nearly three decadesago. my own sporting talents were, at best, lit­ tle betterthan average; i represented the higher cricket and rugby teams at my schoolsbutwent nofurther. in reflection, i preferred the cut, the thrust, and the tactics of rugby; crick­ et i found less appeal­ ing because of the prolonged periods of tedium spent fielding or waiting to bat. i never learned to ac­ cept those passive hours when one was unable to influence materially the out­ come of the game the greatest change in my sporting life came at the end of 1964. beginning inthe early 'sixties, two renegade californians, 'grubby' clark and hobie alter, began ex­ periments aimed at producing a lig h t­ weight material to replace the balsa wood then used inthe manufacture of surf­ boards. to prevent de­ tection by others working on the same project,clarkand alter were forced to work at night in their and othergarages spread across southern california. finally, by theend of the 'fifties, they perfected the first polyurethane foam blanks from which lightweight surfboards could be made. thefirstconsignmentofclarkblanksar ri ved in cape town probably in late 1962 i j j~ '■ ■ -. forshaping by alter'slocal alter ego, john whitmore. by 1964, whitmore surf­ boards made of clark foam were prized asmuchbythelocalsurfinggremmiesas areporsches by today's yuppies. surfing had become the major recreational ac­ tivity for the non-aligned renegades at many cape town high schools. amongst the small group of mavericks with whom isurfed.threesubsequently became international rugby players; another, the classical high school 'failure', has since received the state president's award on two occassions — the first for braver/; thesecond received last yearfor being south africa's top exporter; two others have achieved financial success in top management positions; theseventh married my professor of surgery's march 1988 vo l 3, n 0 1,1988 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) daughter, and the eighth overcame a heroin addiction, probably the second greatest danger faced by a surfer; second only toan encounter with a great white. i have always wondered whethersurfing attracts the more creative, less subser­ vient mindsandwhetherthat is why it is oftenconsideredasubversive activity, as it was by some of my teachers in the en­ lightened'sixties. the important lesson i learned insurfing and from dai ly contact with that group of free-thinkers, was that i preferred an individual sport to team sports. i disco­ vered that the individual sport allowed me to study myself in a way not possible in any other activity that i had ex­ perienced either then or have ex­ perienced subsequently. after school and two years spent in the army and overseas, i started rowing and running. asdescribed in loreof running, these sports taught me that my perso­ nality profile is that of thesecretive, am­ bivalent, inquisitive ectomorph. ilearned too that my body needed regularatten tionandthatwithproperpreparationit could beaskedtodothingsthat my logi­ cal mind would consider impossible thus i learned the dangers of setting goals that were too low, and of the need to acii,the important lesson i learned in surfing and from dally contact with that group o f free­ thinkers, was that i preferred an individual sport to team sports. i discovered that the individual sport allowed me to study myself in a way not possible in any other activity that i had experienced either then o r have experienced n subsequently." deck hands". i have often wondered why somanyofmycolleaguesareconvinced that individually they each represent one-half of the total universal comple­ ment of geniuses. i learned tootheimportanceof honesty; in individual sports there is no one to blame but yourself. finally running gave me the time neces­ sary for the mental solitude to be crea­ tive, to write a book on running, to plan and developa research programme, and toponderthespiritualcomponentoflife more recently but especially after the publication of the lore, my sporting goalshavealtereddramatically.no longer do i consider it necessary to run in com­ petition to discoverthe optimum train­ ing methods, orthefluidsthatshould be drunk before and during competition, or the effects of different diets on perfor­ mance. these questions must now be answered more definitively by others in thelaboratory.mycompetitiveenergies that l previously lavished on sport must now be directed to academic goals, to produce good students and good research. i have learned that the measure of one's academic contribution, at least at my non-genius level, is not one's writ ingsorone's research, butone'sstudents m a r c h 1988 v o l 3, n o 1,1988 whose giftsare greater. in the immortal words of one university chancellor — "there are at any one time, only one or two supremely intelligent human beings aliveontheearth.therestofus,yaleand stanford graduates included, are only so i now believe that i have run hard enough for long enough. itistimeto accept the limita­ tions of age and to choose the easier sporting path; the path of sport for health, not peak sporting p erfor­ mance. so l have learned to cycle and to swim, activi­ ties which are less demanding thanis running on the ag­ ing musculo-skele tal system but which are equally taxing on the heart, the lungs and the metabol­ ism. sport then has given me a hobby andaprofession.lt has been my most diligent and de­ manding teacher you may under­ stand why i con­ sider sport to be such an important human activity and why i believe that as doctors we must ensureourowncontri bution to the promotion of sport by striv­ ing to provide, as an absolute minimum, optimum medical care to the sporting community. cept noth i ng less than my a bsolute best. next i discovered my physical limitations asanathleteand learned that weall have both intellectual and physical limitations that must be faced and accepted with humility and without malice to those 9r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) aerobic dance injuries based on talk given by d r . gordon ir v in g at the t r a u m a 87 s y m p o s iu m organised by the red cross society in port elizabeth on 27.11.87. t oo many the term aerobics conjures up an image of a jane fonda-like figure dressed in leopard leotard with matching leg warm­ ers and lipstick. although such individuals certainly are found in aerobic dance classes around the country, the average exer­ ciser is far removed physically from this lithe, fit stereotype. however, nomatter what physique the exerciser has, the mental self-image the aerobic dancer conjuresupofhimorherselfmaybe oneofatarzan-likeora victoria principal-like figure. in the attempt to become like their idols, the dancer may go to great lengths, exer cisingsixormorehoursa week, whilst starving on the latest fad diet. this combination of fre­ quent high intensity, sometimes incorrectly performed exercise, togetherwith diets low in essential minerals and i i in the attempt to become like their idols, the dancer may go to great lengths, exercising six o r more hours a week, whilst starving on themm latest fad diet calories creates a variety of injuries. the principle causes of aerobic injuries are: 1. overuse— repetitive stress of soft tis­ sues and bone creates microtrauma which, if insufficient time is given for recovery may pre­ cipitate mu­ scle tears, tendonitis, orstressfractures repeated movements which stress ana­ tomically malalignedjointsmay causese vere irritation necessitating a long layoff. one way of self monitoring and avoiding some of the overuse problems is to use what i call, the educated thumb tech­ nique: pressure of the thumb orfingers down the medial and posterial medial aspect of the tibia may reveal a tender­ ness, duetoeitherperiostitisorstressof the cancellous bone. this is commonly referred to as shinsplintsandiscaused by excessive rotational and compressive forces acting around the tibia. if this medial tibial stress syndrome is getting worse, indicated by an increased tender­ ness on tibial pressure, the individual should reducethe high impactjumping and running part of the aerobic class. non-weight bearing exercises such as cy clingorswimmingshouldbesubstituted until theshin isfeeling less 'delicate: when the tibia is no longerfeeling excessively 'delicate' full aerobic classes can be re­ sumed. such self monitoring together with relative rest could save the par­ ticipant much future suffering and perhaps extensive and usually totally unnecessary tests and treatments. 2. muscle imbalancesand inflexibil­ ity — women as a group are far more flexiblethanmen.thiscreatesproblems in programme design and injuries the hyper-flexible female tends to have an march 1988 vo l 3, n 0 1,1988 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) increased incidence of joint discomfort when joints are taken beyond their nor­ mal range of movementduringstretch ing. the more inflexible males tend to have a higher incidence of acute and chronic muscle strains the regularjog ger with his inflexible calves and ham­ strings has an increased predisposition to tears when stressing them in the un familiaraction of aerobic dance routines 3. im proper training— whilst various organisations are attempting to address the problem of inadequate instructor training, there is still a woeful lack of knowledge, or poor utilisation of knowledge, by many instructors the poli­ cy of some gyms to designate a promis­ ing club member as an instructor and, with the minimum or no training, place him onthe podium can causenumerous problems many exercises appear to be designed because it gives the feeling of fatigueorstressin certain portionsof the instructor's or instructress's anatomy. these'designerexercises'are given with scant regard forthe impossible contor tionsand abnormal joint positions that otherlessflexibleorfit members of the class have to get into. 4. poor technique — exercises which are safe when done with control may be­ come damaging when incorrectly or rapidly performed. the lower back is oftenthefirstto complain asfacetjoints and soft tissue structures are placed un derstressexerciseswhichcausetheback to arch while attempting to strengthen theabdominalmusclesare 'killers' asfar asthelumbarspine is concerned. i i exercises which cause the back to arch while attempting to strengthen the abdominal muscles are killers 'as for as the lumbar spine is concerned. ’ repetitive flexion and rotation exercises done at high speed for long periods of time, load and unload the spinal strucm ar ch 1988 vo l 3, n 0 1,1988 tures and also cause pain and damage 5. hardsurfacesand im proper foot­ w e a r— whereas few would argue that bare concrete floors probably create more orthopaedic stresses, there is no good evidence that wooden or sprung wooden floors or a mat on a concrete floor are any different regarding the numberortype of injuries (garrick et al 1986). there is also controversy about the correct type of footwear, a recent survey showing running shoes to be perhaps more effective than aerobic shoes in preventing injuries. the instructor's problems the instructor whilst usually a caring type individual has certain constraints when structuring classes. these con­ straints include: 1. set time — in 30-45 minutes the in­ s t r u c t o r s togivea'good class'. a'good class' often means a combination of pools of sweat accompanied by groans from lactate induced, local muscle ex­ haustion. run over time and there are moans as the next class isdelayed. finish before time and there are moans that peoplearenotgettingtheir moneys worth, irrespective of the workload completed within that time 2. different ages, abilities and sexes o f participants — cateri ng fo r classes of both sexes, whose ages may vary i from teens to elderly, with fit . inesslevelsfromtotallyunfitto i j l fitcreatesalmostinsurmount / //able difficulties go too slow or / / / toofastandmoansaresureto followandadissatisfied client is not good publicity for thegym. 3. lack o f knowledge— both practical and theo­ retical knowledge may be unattainable or costly for the indivi­ dual instructor. as yet in south africa there are no mandatory re11r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) quirementsforanytype of aerobic dance qualification. until the general public become aware of the existence or meaning of such training certificates the onus on education will rest squarely on the con­ science or ability of the instructororgym owner. some proposed solutions 1. instructor training — vital to the safe run­ ning of aclass should bea well informed, caring indi­ vidual. the instructors knowledgeshould not only include howtoexercise cor­ rectly but also basic dietary principles to inform and edu catetheanorexicpersonalities found at any gym. (fig 8). 2. an additional instructor— an extrainstructorshouldbe present at all classes to correct alignment faultsintheparticipantsorchangeexer ciseswhilsttheyareexercising. in particu­ lar, abdominal exercises should be perfor­ med with the low backflaton the ground. performingfullsit-upsallows theilio-psoas muscle to act as a lever at its origin on the lowerlumbarvertebrathisplaces excessive strainson both thefacetjointsand soft tis­ sue of the spine and may cause back pain. at thesame timea full sit-up does not have any more training effect forthe abdominal muscles than asimpleshoulderraiseto30 degrees (fig 9) or a twist cu rl (fig 10). 3. grading of classes— classesshould be graded into beginners, intermediate and advanced. thisgrading should allow participants togoupordown depending on ability or injury. a.participantwlonitoring— selfmon itoringtechniquessuchas the'educa­ ted thumb' (see earlier) and teaching people how to taketheirpulsesareim portant tech­ niques which should be taught. monitoring the pulse rate ensures' that an adequate level of activity is maintained during theaerobicphase of aclassandalsoenablestheparticipantto pick up irregularities of the heart rate if thenumberofectopics(extra beats) oc­ curs more frequently than six per minute, medical advice should besought. s.programmedesign— aclassshould f i t be well thought out and preferably choreo­ graphed prior to performance movements should be sequenced so muscles don't suffer imbalances and jointsattain a wide rangeof motion. if us­ ing handorwristweights0,5-1kg should be themaximum used. ankle weightsare potentially dangerousandshould not be used. low impact aerobics (where one footisalwayskeptonthegroundtotryto decrease stresses caused by repetitive jumps) should be used for low fitness or injury susceptiblegroups. repetition of exercises enables the participant to de­ velop a sense of what the exercise cor­ re ctly perform ed feels like. the programme design will obviously be in­ fluenced by all the factors previously mentioned. if there are three points i would encourage an in­ structor to commit to mem­ ory, these would be: 1.the body isaslowacco m odatortostress— one should not cater for the fittest individual in the class but bring every­ body gradually up to a standard of acceptable fitness. 2. rest may be a four letter w ord , but rela­ tive rest is im portant— most injuries improve by avoiding the stressful exer­ cise which precipitated it and substituting another ex­ ercise for the time being. 3.painisyourfriend-pain should always be regarded as a reminderthatthe body is being damaged and itshould betreated with respect, not ignored. the above suggested solutions have several draw backs which can be sum­ marised in three words, expense, ex­ pense and more expense. a t present south africansenjoy exceptionally cheap aerobic dance classes and there are few regulations limiting the giving of such classes so the cost of education, extra in­ structors and individualising program­ mes becomes prohibitive for the gym owner. it is therefore unlikely that the type of injury seen in ourclinics will alter significantly in the nearfuture aerobic dance classes have enriched the quality of life of thousandsof south afri cansand there is no reason todoubt they will continue to do so. however it is the responsibility of all those who take such classes to ensu re the exercises are done correctly and safely. education of both in­ structor and pupil would do much to decrease the problems and increase the pleasure of this important form of exercise. iwouldliketothankthe back school (pty) ltd for use of their illus­ trations in this article r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ultraman peaks d he ultraman series re­ ached a point of high drama during the iron man triathlon in feb­ ruary when pretoria's nic bester excelled to gain an overall lead in the competition. but fortune failed to smile on his pretoria club-mate piet mare, who fell out of the multi-event competition when he retired in great pain from iron man with 18km to go in the marathon. mare, who was in ultraman contention among the top 10, spent the night in hospital because of problems with his kidneys. he has been advised to stay away from any form of physical exer­ cise for at least two months. this has come as a bitter blow for the talented triathlete, who has a string of iron man gold medals to his name it means that he will not receive his r2 000 prize money for winning the vasbyt 160km cycle tour, which was one of four compulsory events in the series the other three are the hansa duzi canoe marathon, the iron man and the comrades marathon at the end of may. the four voluntary events are the jse 50km, the midmar mile swim, the argus cycle tour (this saturday) and the two oceans marathon over easter. mare's demise means that natal's keith ellerker, who finished on his rear wheel at the vasbyt, will be awarded the r2 000 for first ultraman home in the ride. bester, meanwhile, continues to as­ tound with his uncanny all-round ability. he claimed fourth position in the iron man, which took in a 20km canoe at hartebeespoort dam, a 96km cycle and a standard marathon to sandton (42,2km). bester came out of the water among the top 20 canoeists, then powered his way through the field to voortrek kerhoogte in the cycling, which he fol­ lowed up with a superb 2hr 56min marathon to claim fourth behind rock ey montgomery, henk watermeyer and gerhard uys. the midmar mile earlier saw george janos move up to third position and duzi king graeme pope-elis slip down to 6th in the top 10 ratings but a mighty effort by "the pope" in iron man, saw him shoot straight back up to 3rd in the ultraman after a 6th at iron man. janos hung in grimly to claim 8th at iron man and now lies fourth overall in ultra man. the victoria lake club triathlete is de­ termined to creep up in the ratings in march when he tackles the argus cycle tour in cape town. janos' cycling has improved dramatical­ ly this year and he should get away from the pope in the cape mountains, along with bester. then the dice will be on for second and third spots in the final run-in to the ultraman competition when the field takes on the two oceans 56km road race with the grand finale, the com­ rades marathon. for further information, please contact tracey mawer of sports international at (011) 883-3333. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ' ‘v v 4¥ a \ u r n urlia/c sasma news sasgvnuus he south african sports medicine association recognized the need for scientific information and training methods for the very popular long distance running events, notably the world known comrades marathon, and devoted the forthcoming sports medicine congress to the various medi­ cal and physiological aspects of running. the growing popularity of this sport alarmed the medical community be­ cause the facilities to treat the vast num­ bers of casualtiesarenot always optimal. itisalsoimpossibletoruleoutallcasesof possible myocardial infarctions, and it is expected that some cardiac emergen­ cies might occur. dehydration, heat dis­ orders, and overhyd ration aretheother problems that have to be taken care of. dr. d.p. va n velden most of the medical and physiological problems of running can be prevented. the varioustopics presented by experts in theirspecificfields will inform the ath­ letes, theircoachesandtheorganizersof the possible hazards that might occur detailsofthecongressaretobefoundin the journal, or may be obtained from: margaret simpson continuing medical education university of natal ro. b o x 17039 concella4013 tel: (031) 254211 or dr. r. rathgeber, tel: (031) 561-1777 in die tydskrif verskyn daar ook instruk sies vir skrywers vir artikels wat aange bied word vir publikasie in die suid afrikaansesportgeneeskunde tydskrif. dit dien ook vermeld te word dat artikels wat gepubliseer word in die suid afrikaansesportgeneeskundetydskrif, kwalifiseer vir subsidiedoeleindes van navorsingsuitsetteviruniversiteitesoos omskryf indie nasop02-014(87/07)vers lag. ons hoop dat dit akademiese geneeshere sal motiveer om the pub liseer in ons tydskrif insake onderwerpe rakende sportgeneeskunde. op hierdie wyse sal dit die standaard van die in houdelike van ons tydskrif kan verhoog, sodat die publikasie van groter nut kan wees virdiegene wat belangstel in hierdie terrein. ons poog ook om die artikels so tort as moontlik te hou, want ‘n besige al gemene praktisyn het net nie tyd om languitgerekteartikelsteassimileernie. dit is een van die hoofdoel witte van die sportgeneeskunde vereniging om sy lesers op hoogte te hou van belangrike mediese en fisiologiese aspekte van sportbeoefening. kommentaar en bydraessal verwelkom word. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) w o k reviewm _ drugs and performance in sports b y richard h. strauss, m.d., wb saunders company. 1987 pp 221. r f the numerous books on sports medicine that ap­ pear daily on the market, this book can be considered asoneofthemost useful guides on the effect of drugs and performance aids on athletic achievement for the practising physician, in the era where so many patientsondrugs take part in some form of exer­ cise or even competitive sport, doctors shou i d be awa re of the i n fluenceofthevariousprescribed medications on exercise perfor­ mance. even healthy peoplecon sult their doctors on various aspects of ergogenic aids in sport, as well asnutrition, dietary supplements and fluid and elec­ trolyte replacement in sport. doctors treating competitive athletesshould'also be aware of chemical substances that are banned during athletic com peti­ tion,and prescribeasafealterna tive, oradvise his patientson the adverse effects of doping in sport. this book evaluates the use of pharmacological, biological and psychological methods thatare used in attempts to improve sports performance, including i discussions of harmful side ef­ fects and how common thera­ peutic drugs can affect athletic prowess the topics covered in­ clude objective information on nutrition, oxygen transport enhance­ ment, anabolic steroids, stimulants and depressants,drug testing, psychological aidsand therapeutic drugs in sport and exercise. the contributors are all well known experts in thefield of clinical and sports medicine, and the text is clearly directed to the medical profession and sport scientists, although coaches, sportsmen and sports administrators would also find this book very informatoarch 1988 v o l 3, n 0 1,1988 ' 'it win answer ali the questions on which drugs— if any— enhance or impair performance ’ in south africa, drug use by ath­ letes is frequently in the news, anditisimportantforphysicians and other health professionals to have ready access to themedical andscientificinformation about such use thefirst section of the book deals with drugs and their perceived or real enhancement of athletic performance, and the second section discusses the ef­ fects of therapeuticdrugson ac­ tive individuals — especially on their musculoskeletal and cardi­ ovascular systems. ifound this book very applicable to the south african situation, and would recommend it to any doctor who cares for athletes and patients with a keen interest in exercise. it will answer all the questions on which drugs — if any— enhanceor impair perfor­ mance, whether there are any harmful side effects and what the ethical implications are. reviewer: drd. van velden c linical s p o rts m ed icine by robert c cantu 1984230 ppcolliermacmillan clinical sports medicine pub­ lished by the collier macmillan press, toronto, canada is edited by robertc cantu m.d. it isa book containing selected papers presented atthe annual meeting of the new england chapter of the american college of sport medicinein 1982. each chapter is written by a different author which gives much individuality. unfortunately the extreme variation in subject material means that the book lacks cohesion. the section on han­ dicapped sports is unusual and most interesting. this is not a book for the casual sports medicinedoctorbutismeantfortheen thusiastorthedoctorwithaspecialised interest. reviewer drc. noble mbbch fcs(sa) r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) aqua aerobics is safer erobicsisanexcellentform of exercise and is very popular. however, it is not suitable foreveryoneand recently an alarming number of in jurieshascometothefore with this in mind, and having discussed with medical and paramedical profes­ sionals, the attributes of water therapy, physical sports instructor, tommy rashed has developed aqua aerobic exercises. tommy told medical observer that the concept involves a carefully co-ordinated exercise routine carried out in a swim­ ming pool. "the water adds exertion to the exercises, butatthesam etimesupportsthebody and relieves the joints of unnecessary pressure and possible injury" as a physical sports instructor, which in­ cluded scuba diving, tommy rashed who trained and qualified in israel and now lives near pretoria has observed with in­ terest the overwhelming popularity of these aqua aerobic exercises which he has introduced at the hoogland health hydro. 'a wide variety of people are now hap­ pily participating in exercise "thisincludesallagegroups, both young and old, as well as people of all fitness levels. "some people;' said tommy, "were soover weightthattheycouldnotpreviouslyex ercise, but much to their astonishment are now fully participating in aqua aero­ bic exercises." people whoarenowenjoying this include those who had not previously partaken of exercise because of certain injuries sustained eitherf rom other formsof ex­ ercise or sport or because of medical problems. explainedtommy:"withaquaaerobicex ercisealltheobjectivesofregularexercis ing are not only achieved, but are en­ hanced by the fact that the water is work­ ing directly onto the skin, muscles and cellulite giving obvious beneficial results "we believe this to be an up and coming trend in popularexercising, not only for people already participating in exercise, v w m p e n fo in sports injury and trauma. didophenac sodium 50 mg (entericcoated tablets) reg. ho. k/5.1/255 (w et/a ct 101/1965) c ib a -g e ig y (pty) ltd p .o . b o x 92 isond o 1 6 0 0 f o r full p re s crib in g n fo rm o tio n p leose re fe r to the m .d.r. but alsoina large numberof people who have previously been excluded from ex­ ercising due to injuries and medical problems." due to theoverwhelming demand, tom­ my rashed hascompleted an audiotape cassetteoftheseexercises, which ismade pleasurable, too, becauseofthetranquil background music. m arch 1988 vo l 3, n 0 1,1988 these tapes can be obtainedby writing to tommy rashed atthefollowing address: p. 0. box 34203, erasmia 0023. the price of the tape "aqua aerobic exercises" is r18,00 plus postage and packing. a c k n o w le d g e m e n t: the medical observer — oct 1987 16r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 'herafy. management of long­ distance runners by physiotherapy by cary m . sobel bsc. (physiotherapy) rand. to the numberof years of running experi­ ence, the finishing times he wishes to , achieve, and hisprevioushistoryof injuries, .. has a bearing on the approach to both in\ 4 *severity&typeof injury the physiotherapist assesses the extent of the injury, and modifies ma r c h 1988 vol 3, n 0 1,1988 ecause of the popularity of long-distance running in this country, the doctor is increasingly being faced w ith injured runners. often the runner is ad­ vised by a doctorto lay-off foran extended period toallowan injury to recover whilethis advice will benefit the patient, 'rest is a dreaded 4-letter word to most runners the demands that are placed on the runner to consistently cover mile­ ages as high as 50-120kmsper week in preparation for the comrades marathon, make the runner re­ luctant to stop running even fora very short period. sports physiotherapy, which today offers a dynamic and aggressive approach, en­ ables runners to continue their training without too long an interruption. no longer is physiother­ apy a palleative applica­ tion of heat and mas­ sage, but rather a holistic approach to effective injury management. *cause of injury each running injury has an identifiableandtreatablecause, and unless that cause isisolated and treated, a complete cure will not result. this cause may take the form of biomechanical abnormality, incor­ rect training methods, incorrect orcollapsed shoes, over-useorover loading. explanation of the mecha­ nism of the injury to the runner will educatehimregardingtherootofthe problem and equip him to avoid re­ currences the runner's training programme |§| accordingly the runner can usually continue f running but only to the point where he actually starts to feel discomfort. a more severe case may ne­ cessitate only a few days rest if treatment is administe­ red promptly an accurate assessment of how long a runner needs tobe'offtheroad'isimpor tant as the runner will be more agreeable to curtail all running if he knows that this isa temporary measure for a pre-determined num­ b erof days absolute rest is prescribed only in thecase of astress frac­ ture, tendonitis with crepitus, or a severe muscle rupture * assessment of the runner fheassessmentoftherunnerasto r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) jury and patient. the beginner, still undergoing musculo­ skeletal adaptation in his first 9-18 months typically picks up injuries such as iliotibial band friction syndrome, 'run­ ner's knee; and shinsplints. the more seasoned runner incorporat­ ing speed, hills, and higher mileages into his training programme, would tend to pick up injuries such as chronic ham­ string and calf muscle tears. theinjuredbeginnermayonlybeableto run for 15 minutes before the pain be­ comes severe enough to stop running; whereas the seasoned runner may be able to runan’e a s y^ k m marathon with a 'niggling' hamstring injury. * activity during recovery the runner, if made to rest completely while injured, will becomecardiovascular ly unfit as well aslosingmusculo-skeletal conditioning. an alternative sport which will not aggravate the injury should be prescribed forthe injured runnerduring recovery. dependingon thetype of injury, theru n ner may be able to partake in cycling, swimming, or canoeing. stretching and strengthening exercises not affecting the injured site, must not be neglected during recovery. *correct shoe prescription the assessment of the patients feet while standing barefoot, running gait with and without shoes, and the wear pattern of existing shoes playsan impor­ tant part in theoveralltreatmentof the runner. thisassessmentwillestablish the type of foot of the runner (high-arched, normal,orflat-foot); whether he has the correctshoetosuithisfoot,andthecon ditionof the shoe based on these examinations, a correct shoe prescription may be made. inserts forth e runner's shoe may help the con­ dition in the early stages for example, heel raises may be recom­ mended forcalf strain and achilles tendo­ nitis lateral wedges for iliotibial band fric­ tion syndrome, and medial wedges for 'runner's knee'. used asa temporary measure toalleviate symptoms, the runner can be 'weaned' o ff these supportsas healing takes place in the event of recurrence of the injury, these supports could become a perma­ nent solution. correct training programme most injuries in distance runners are chronic overuse injuriescaused by doing to o much, too fast, too soon'. therunner'strainingprogrammeshould be carefully examined and broken down into the5 different variables which must be modified in the event of injury. these are the frequency of runs per week, total weekly distance, pace of run­ ning, running surface and gradient. a gradual progression of the different variables and the continual monitoring of how the runner is coping forms the basis of a good training programme. * deeptransverse frictions thistechniqueasdescribedbycyriaxhas become the treatment of choice for both acute and chronic injuries. adapted tothesiteandstageof the inju­ ry, deep transverse friction is used for muscle, ligament and tendon injuries i i cause of injury each running injury has an identifiable and treatable cause, and unless that cause is isolated and treated, a complete cure will not re su lt" cross friction massage, according to cyri ax, must begivensufficiently deeply and vigorously across the affected fibres to the correct spot with sufficient sweep. with deep transverse friction, rapid results are seen after only a few treat­ ment sessions. corrective stretching exercises stretching is a very useful means of in­ jury prevention and of promoting heal­ ing of an injury. training causes muscles to become inflexibleandshort,andthe very act of run­ ning produces relative muscle im­ balances which can result in injury. gentle stretching during the repair phase of an injury will tend to remodel thefibresofamuscleorligamenttearin the direction of loading. stretchingshould bedoneslowly with no bouncing, taken to the point of slightdis comfortand held for 15-30 seconds. * strengthening exercises strengthening exercises play an impor­ tant role in preventing muscle im­ balances. exercises can also be used to correct patella 'maltracking'— for exam­ ple, in'runner's knee: corrective strengthening exercises to an injured structure will promote adequate and complete healing. *anti-infi_ammatory modalities the sports physiotherapist is equipped with modern machines which are excel­ lent modalities for the reduction of in­ flammation, pain relief, and the promo­ tion of healing. modern equipment includes interferen­ tial therapy, didynamic current, cura pulse and the conventional ultra-sonic. *"self"-treatment active participation by the patient apply­ ing self-treatment at home, not only ac­ celerates the healing process but also has a psychological benefit as the patient feelsthatheisdoingsomething positive towards his own recovery. thephysiotherapistshouldexplainhow to make and apply an effective ice-pack, which can be applied for 20-30 minutes 2-3timesdaily.stretching&strengtheningexercisesathomeshouldbeactively encouraged. *return to running as it isimpossibleto know howthe injury will respond in the initial stages, a trial period is essential when attempting to return to running. a fla t grass field is optimal as this allows for minimal stress and ample cushioning. the runnershould run completely'pain free' on alternate days building up at 5 minute increments from 15 minutes to 50 minutes. if, however, pain develops running should be stopped immediately. with this holistic approach to both inju ryand patient, the physiotherapist plays an invaluable part ingettingthepatient onto th e road' to re c o v e ry .^ references 1. cyriax, j. (1977) textbook o f orthopaedic medicine 9th ed itio n baillieretindall, london 2 8-35 2. noakes,t.d.d985)/.ore o f running, oxford univer­ sity press (publishers) cape town. 325-396. l.5obe\.<m.stretchingandtheiongdistancerunner s a runner nov1984 (12-13). m arch 1988 vol 3, n 0 1,1983 18r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) osteochondritis dissecans clive noble m b c h b . f c s (s a ) n 1887, exa ctly one hundred years ago, f. konig presented a paper about loose bodies in joints.1 he concluded thatthere were three causes for loose bod­ ies in ajoint. 1. severe trauma causing a breaking o ff of apart of thejoint 2. lesser trauma which might con­ tuse the bone giving rise to necrosis which then might separate 3. minimal trauma where some predis­ posing factor would appear to cause the separation. notmuchhascha nged in 100 years it is now believed th a t the third category is due to an ossification defect in adoles­ cence.2 in old age vascular insuffi­ ciency may cause o s t e o n e c r o s i s with loose body formation. it may wellbethattheos sification defect found in adoles­ cence may also be associated with vascular insuffi­ ciency as smillie5 has suggested. not all anomalous ossification centres tres become osteo­ chondritis disse­ cans. recent work using bone scanning with technetum 99 has shown that osteochondritis disse­ cans can be separated from anomalous ossification centres. va riabledegreesof trauma will to tally dis ruptthevascularsupply giving rise to the classical features of osteochondritis dessicans. it would appearthatinsportsmen these cond cause is possibly more common ow­ ing totheconsiderabledirector indirect violence which occurs in sport. osteochondritis dessicans may occur in anyjoint but is more commonly found in the knee and to a lesser extent in the ankle. in the knee the most common site is on thelateral sideofthemedial femoral con­ dyle and to a lesser extent on the inferi­ or surfacesofthefemoral condyles. the patella israrely damaged. in the anklethe tw o sites are anterolateral and posteromedial on thedom eof the talus. the fragment loosens from the underly­ ing bone but may remain in situ. here it may reunite with the rest of the boneor develop what could bedescribed as non­ union and fail to unite. this fragment then usually displaces and becomes a loose body in the joint. partial attach­ ment may also occur. if th e f ragmentremainsin situ knee pain and swelling usually occur. if the frag­ ment displaces — catching and locking with episodes of instability mayoccur as well. radiologically the subchondral bone separatesfromthefemoral condyle by a clear curved line. the bone is not usually sclerotic initially. if displacementoccurs a loose body may be seen radiologically. bone scanning is useful for separating os teochondritisdessicansfrom anomalous ossification centres and also to assess healing. in the acute stage a fracture line may be visualised in 24 hours. this line usually re­ mains very clearfortwotothree months. with healing, thefracture line gradually disappears. treatment it has been fou nd that most cases underthe ageof 14 years will heal if they are rested from physical activities this rest may be on ly rest from sport but in some cases the useofacaliperand crutcheshasbeen found tobe neces­ sary. in cases over the ageof i4years be­ cause of the relati­ vely poorresultsof conservative treat­ ment, surgery is often indicated. excision of the fr­ agment in a non weightbearingsit uation or internal fixationofthefrag ment which has not been displaced is required. loose bodies should be removed. osteo cartilaginousbone grafting may be required if a large defect is present in th e w eight bearing area. unfortunately caseswhere there is a large defect in the weight bearing area often develop severe osteoarthritis of the involved compart­ ment. references " 1. konig f. (1887) uber freiekorper in den gelenken dtsch z klen cher. 2 7 p 90-109 2. barrie hj. (1987) osteochondritis dessicans 1887-1987 j.bjs 69b 5 p. 693-695. 3. smillie is (1960) osteochondritis dessicans: loose bodies injoints: etiology, pathology & treatment. pub e&slivingstone march 1988 vol 3, n 0 1,1988 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nb: please fill in the reply paid card if you haven't done so already. sports miedicini spcrtgienisiiskundi ■ . . . . . ~ -s . • ‘ . -,.s! ... . . »>— 0 « 4 tm m m o n > m 'w m a *^ucrr*ni*»**-i»ooa«vn wpnn* *• n x r ^ k ' n i ^ m i n o n m n o o r lalunmffioutomanmmrkmpomwqnkraowora. sports proceeding book please note if you were a registered delegate atthesecond sports medicine congress during 1987, the cost for the proceedings was included in your regis­ tration fee intheeventthatyou havenot yet received your copy, please contact medical tribune at (011) 803-4745. doc­ tors whodidnotattendthe congress can obtain proceedings from medical trib­ une at a cost of r20,00. suid-afrikaanse sportgeneeskunde vereniging application form aansoekvorm full m em b er/v o ile lid r 25 s tu d e n t m e m b er/s tu d en te*lid r5 south african sports m edicine association h um an m o v e m e n t a nd leisure a t im e o f c ha nge 29 ju n e — 1 julyl9 8 8 civic centre, klerksdorp presented by the south african association fo r sport science, physical education and recreation in collaboration w ith the city council of klerksdorp biennial national congress international symposium on research in sports science, movement education, recreation and tourism and exercise science procrammethemes sports science the nature of sports science sports science at the service of sports practice needs of sports practice as priority in research report on research movement education view of the future of education view of the future of training movement education in practice research in movement education recreation and tourism planning of sports and recreation centres parks and playing areas crisis management and communication research needs and advantages the future of tourism and legal limitations research in the black market report on research exercise science exercise programme leadership and planning the fitness industry in perspective biokinetics, science of the future? myths and misconceptions report on research forfurtherinformation please con tact: the director, saassper, hatfield forum west, second floor, 1067arcadia street, hatfield pretoria 0083 tel: (012)43-5594/5/6 logo design competition sports m e d ic in e 5pcrtgienieie5kundie m arch 1988 v o l 3, n 0 1,1988 tel no/tel n r ................ m a s a no/m vsa n r ................ fuft m em ber medics* oraesitioterrew+io are members ol m a s.a. voile lid: k ‘fi ;•>itf 0f*ic!i£.yv'-s w ilt iodo vdilsi.*» m.v.s.a •: student m em ber m ■ di s n id e r ie s clinical years studente-lede: m ediate •r'hi:'>‘i '-''ess jare adpi-caiioaaformefnbershtools a s m ashouiade&entio 'n o .u’ d y $ -a s m a . nal'itj.u foru,ti wttsf, 1067a rcadus ljt1*)' p r e io a rc-bl cdeques *o accompsnvme-nbersrup form the sasma logo is due for a revamp! readers of the sports medicine are en­ couraged to try their hand at design­ ing a new and exciting logo for sasma. a prize of r200 and a mystery gift is in the offering for the best design. send in your colour artwork together with your name, address and telephone number to: sasma c/0 sports medicine p 0 box 3909 randburg 2125 closing date: 15 june 1988 1st southern african conference on suicidology theme: evaluation, treatment, prediction and prevention. 2nd/3rd september 1988 elangeni hotel durban contact people: scientific programme: professor l. schlebusch, head; sub department of medically applied psy­ chology, department of psychiatry: faculty of medicine, university of na­ tal, durban. p.o. box 17039, congella, 4013. tel: (031) 254211 x 324. organizational aspects: mrs. margaret simpson, department of continuing medical education, p.o. box 17039, congella, 4013. tel: (031) 25-4211 x 327. 20r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sou th afr ic an jo u r n a l of sports medicine sportgeneeskunde j o u r n a l of the s .a . s p o r t s m e d ic in e a s s o c ia t io n t y d s k r i f v a n die s.a. sportgeneeskunde-verenjgin g v o lu m e 6 num ber 1 march 1991 contents e d ito r in c h ie f: c liv e n ob le a sso c ia te e d ito rs : p roft d n oakes d a w ie v a n velden a d v i s o r y b o a rd : t ra u m a to lo g y : e tienne h u go p h y s io th e r a p y : j o y c e m orton n u tr itio n : m iek e f aber b io k in e tic s: m artin s ch w elln u ss e p id e m io lo g y : d erek yach r a d io lo g y : alan s cb er p h a rm a c o lo g y : j o h n s tra u gh a n p h y sica l e d u c a tio n : h a n nes b otha in te rn a l m e d icin e: f rancois r e ti e f editorial c om m ent the use of anabolic-androgenic steroids in sport ...................................................... .............. 2 physiotherapy and the sa sport medicine association .................................................. ........... 3 rugby the role of a system of two referees in the prevention of rugby injuries ......................... 4 physiological profile of the senior south african rugby player ............................................. 7 cricket ' sports injuries encountered on a five week international cricket tour .............................. 10 physiotherapy update the physiotherapy treatment of a hamstring tendon injury ..................................................... 16 exercise-related injuries the prevention of exercise-related injuries among south african army re c ru its: a re v ie w n utrition fat in the diet 17 21 photographs courtesy o f h h o fm e isic r a n d c best s a s g v s a s m a p u b l i s h e d b y t h e s o u t h a f r i c a n s p o r t s m e d i c i n e a s s o c i a t i o n h a t f i e l d f o r u m w e s t 1067 a r c a d i a s t r e e t h a t f i e l d p r e t o r i a , 00 8 3 t h e jo u r n a l o f th e sa s p o r is m e d ic in e a s s o c ia tio n is p u b lis h e d b y m e d p h a r m pu blicai io n s, 3 rd f lo o r n o o d h u lp lig a c e n t r e , 2 0 4 b h f v e rw o e rd d r iv e , r a n d b u r g 2 1 9 4 . t e l: (0 1 1 ) 7 8 7 -4 9 8 1 /9 . t h e vie w s e x p r e s s e d in ih is p u b lic a tio n a r e th o s e o f th e a u t h o r s a n d n o t n e c e s s a r ily th o s e o f th e p u b lis h e r s . p rim e d b v t h e n i u l w im c w p r im in g and p u b lis h in g c o m p a n y (p iv j l id s p o r t s g e n e e s k u n d e vol. 6 n r . 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) our concern on the use of anabolic -androgenic steroids in sport a n ab o lic stero ids w ere sup p o sed ly used b y the g erm ans d u rin g w orld w ar ii to increase aggressiveness and, sub ­ seq u en tly to that war, the soviets began using them in athletes in the late 1940’s. the u n ited states started using them in the e a r ly 1950’s. subsequently, the first syn th etic stero id , d ian ab o l (m ethandrostenolone) w as developed. t he m ost abused categ o ry of drugs to d a y is the group o f d rugs kn o w n as an ab o lic-an d ro gen ic steroids. a n a­ b o lic stero ids are d erivatio n s of the m ale horm one tes­ tosterone, and are used for recuperation for b o d y b u ild ­ ing. t he an ab o lic effect im plies the a b ility to prom ote tissue gro w th and/or repair. the androgenic effect im ­ p lies the a b ility to produce m ale seco nd ary sex character­ istics, ju st as does testosterone. the anabolic effect of these steroids does increase lean b o d y m ass and reduces the p ercentage o f b o d y fat if th ey are used in conjunction w ith con ven tio n al m ethods of stren gth train in g and b o d y b u ild in g . a d eq u ate caloric and d ie ta ry in tak e is necessary. the an ticatab o lic effect is one of great interest because the athlete can recover q u ic k ly from a hard w o rk o u t and train lo n ger and harder. a re w e m issing som e of the ben­ eficial m edical effects ? f rom a m edical p erspective, these drugs are seldom prescribed because of the rather serious and cum bersom e adverse effects such as acne, overaggressiveness, gyn o co m astic, te sticu la r atrophy, liv er dysfu n ctio n , tum ors, ch o lestero l changes and h yp erten sio n in m ales, increases in facial and b o d y hair, deepening o f the voice, en large­ m ent o f the clito ris, sh rin k in g o f breast size and irreg u lar m en stru al cycles in fem ales, and acne, v iriliz atio n and prem atu re clo sure of the gro w th plates in adolescents. a s gevolg van die erns van die probleem , het die suid a frikaan se sportgeneesku nde v ereniging dit n o dig ge vind om ’n sterk standpunt in te neem teen die m isb ru ik van anaboliese stero'iede in sport. o ns is van m ening dat baie m eer gedoen m oet w o rd om jo n g mense op te voed insake die n ad elige effekte van hierdie m iddels. g eko n tro leerd e n avo rsin g op h ierd ie terrein is beperk, daar is in der w aarh eid slegs enkele sterfgevalle aangete ken in die literatu ur. d it b rin g mee dat sportgeneeskun diges se k re d ietw aa rd ig h eid in tw y fe l getrek w o rd . d ie feit is egter d at navo rsin g op anaboliese stero'iede in sulke hoe d o serin gs nie to egelaat sal w o rd nie, en gevo lgtrek kings m oet gem aak w o rd op anekdotiese gevalle van steroied m isb ru ik . d it is te verstane dat atlete u it vrees v ir d issip lin ere optrede teen h u lle, nie genee is om v ry w illig lik na vore te kom om oor gevolge te rapporteer nie. o p grond van ’n uitgeb reide lite ratu u ro o rsig , erken die su id -a frik aan se sportgeneeskunde v ereniging dat die anaboliese stero'iede w el sp ierk rag en spierm assa kan verb eter o n d er sekere om standighede, en dat daar ernstige n ew e-effekte mag voorkom in m ans, vrouens en adolessente. d ie veren igin g stem saam dat anaboliese stero'iedgebruik teen die reels van regverdige m ededing in g in sport is, en dat daar streng opgetree m oet w ord teen atlete w at h ierd ie m iddels m isb ru ik om hulle sport prestasies te verbeter. d ie su id -a frik aan se sportgeneeskunde v ereniging beveel v erd er aan dat atlete beter opgevoed m oet w ord en d at m eer navo rsin g ge'inisieer w o rd insake anaboliese stero ied m isb ru ik . ’n n asionale toetsprogram m oet in w e rk in g gestel w o rd w at deur alle sportliggam e onder s k r y f w o rd . d ie m ediese geb ru ik van h ierdie m iddels m oet h ero o rw eeg w o rd , en daar m oet streng opgetree w o rd teen die verskaffers van hierdie potensieel skade lik e m iddels in sup ra-terap eutiese doserings. d ie standpunt van ons v ereniging is niks nuuts nie in die b y b e l w o rd daar in 2 t im o tius 2:5 die volgende w aarh eid k w y tg e r a a k : “’n a tleet w at aan ’n w e d stry d deelneem , kan die p rys w en slegs as h y volgens die reels m eeding. ” su m m ary and conclusions d oping in sports has a negative effect on sports in the; w id est sense of the w o rd and should be com batted on the b asis of ethical and m edical aspects. h ow ever, in com ­ b attin g d o p in g one should never lose sight of hum an d ig ­ nity. t his calls for a d iscrim in ato ry approach in w hich do p in g co n tro l should never be a p urpose in itself, but sh o uld be regarded as a p rotection of sports and its athletes. d r dp van velden m b c h b , m prax m ed a ssociate e ditor/m ede r ed ak teu r 2 sports medicine vol. 6 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy and the sa sports medicine association in 1980, the south a frican a ssociation for p h ysical e ducation and r ecreatio n (n o w kn o w n as the southern a frican f ed eratio n for m ovem ent and l eisure sciences) o rgan ized a conference in p ort e lizabeth. d rs tim n o akes and d aw ie van velden w ere requested to arrange a sym p o siu m as p art of the conference w hich w o u ld b rin g to geth er representatives of m edical and allied p ro ­ fessions w h o w ere involved in health prom otion and p h ysical a c tiv ity and w ere u sin g p h ysical exercise as a treatm en t m odality. o n the 20th j u n e 1980, d r t im n o akes w ro te a letter to the p resid en t o f the south a frican so ciety of p h y sio ­ therapy, m rs m o lly levy, inv itin g nom inations for p h ysio th erap ists to speak at the sym p o sium . h e also o u tlin ed the three fold objectives of the m eet­ in g : i 1. to define the specific role of each group in the p ro ­ m otion o f south a fric a ’s health th ro ugh p h ysical ac­ tiv ity and the treatm ent o f disease; 2. to define the specific areas that each of these groups covered in the p ro visio n of health care to south a fri­ cans w h o w e re p h y sic a lly active eith er in sports or recreatio n ; 3. to prom ote co llab o ratio n and to co-ordinate the w o rk done b y these gro up s through the form ation of a m u lti-d isc ip lin a ry f ederation or a ssociation for r ecreatio n al and sports sciences and sports m edicin e. d r n o akes ended his lette r w ith the fo llo w in g p ara­ grap h : “we g e n u in e ly feel that this m eeting w ill provide a re a lly im p o rtan t chance for everyo n e interested in rec­ reatio nal h ealth , to get to geth er and delineate th eir co l­ lective roles. we cannot em phasize stro n g ly enough how im p o rtan t w e feel y o u r co n trib utio n to this sym posium and to o u r p roposed f ederation w ill b e ”. a s a resu lt of d r n o a k e s’ inv itation , m rs m o ira van o o rd t and m iss s a lly e ager presented papers relating to p h ysio th erap y, w h ile i w as asked to represent the south a frican s o ciety of p h ysio th erap y. i k n e w that this in itial m eetin g of d isciplines w as of great im portance to p h ysio th erap ists in south a frica. we w ere b eing given the o p p o rtu n ity to develop alongside the m edical profession in the service of sport, sportsm en and sports m edicin e in this country. i k n ew , too, the tre­ m endous co n trib u tio n s w h ich p h ysio th erap ists could m ake in the field. i hoped that from this early s y m ­ posium a perm anent association w o u ld be form ed. i still have a co p y of p ro f n o a k es’ letter and can re­ view w ith real satisfaction, the gro w th of the south a fri­ can sports m edicin e a sso ciatio n (sa sm a ) and the gro w th of the relatio n sh ip betw een the a ssociation and the p h y sio th e ra p y profession. m a n y p roblem s w ere experienced in those early years but u n d er the rig h t leadership the sports m edicine a s­ so ciatio n grew from strength to strength and is to d a y a th riv in g association. it w as a m om entous occasion w hen, at the a g m o f sa sm a in d urban in 1988, the consti­ tutio n w as altered to a llo w p h ysio th erap ists and biokine ticians to becom e associate m em bers. a representative from each group w as asked to serve on the executive com m ittee. m em bers of these diverse groups w hich no w m ake up the a sso ciatio n , are able to share their know ledge th ro u gh the s ou th a frican j o u r n a l o f sports m ed icin e. it is to me a p riv ilege to be given the o p p o rtu n ity to p ro ­ m ote, th ro ugh this jo u rn al, the role of the p h y sio ­ th erap ist in sports m edicin e. p h ysio th erap y encom ­ passes a w id e scope, from the treatm ent o f the acute in ju r y to the final m edical rehabilitation of the sports­ m an so that he m ight re tu rn to his sport. t he profession of p h ysio th erap y has com e a long w ay and to d a y w e are seen to be am ongst the leaders o f sports m edicine in south a frica. it is thanks to the enthusiasm of leaders such as d r d aw ie van v elden, p resident of sa sm a , b rig. e ttiene h u go , past president of sa sm a , m r c liv e n o b le, e ditor of the sports m edicine jo u rn al and p ro f t im n o akes, p resident elect of sasma. that w e are w h ere w e are today, and w e thank them . t hus at the end o f a decade of the gro w th of sa sm a , i can lo o k back and feel p ro ud that i w as present at its b irth. m rs j o yce m orton south a frican s o ciety of p h y sio th erap y r ep resen tative: sa sports m edicine a ssociation sportsgeneeskunde vol. 6 nr. 1 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the role of a system of two referees in the prevention of rugby injuries jr potgieter, jh blaauw and jh malan in the qu est for the prev en tio n of in ju ­ ries in ru g b y the referee has often been m entioned to geth er w ith the coach and m edical and p aram ed ical personnel as h aving an im p o rtan t role to play. h e is expected to a p p ly the law s co rrectly and fa irly w h ile also m ain tain in g the d iscip lin e n ecessary to curb foul play. in term s of in ju rie s, the referee is ex­ pected to fulfil a p reventative function. in spite of the co m p lexity of the gam e ru g b y and the dissatisfactio n w ith referees, w e p ersist w ith the use of one referee. t h is is in co n trast to m ost other team sports. o b servation o f the use o f tw o re­ ferees in ru g b y m atches at the u n iv er­ sity o f stellenbosch led those involved w ith the gam e to becom e convinced of the benefits of such a system . it w as ar­ gued, am ongst o th er advantages, that the use of tw o referees w o u ld resu lt in a d ecrease in foul play. h ow ever, there w as no o bjective p ro o f that such a s y s ­ tem w o u ld be effective. protagonists based th eir su p p o rt o f the system on com m on sense and in tu itio n . there w ere also in d iv id u als and groups w ho w ere not in favour of such an in n o ­ vation. it is again st this background that an em p irical inv estigatio n w as deem ed necessary. j r p otgieter, j h b la a u w a n d j h m alan i n stitu te o f s port a n d m o v e m en t s tudies u n iversity o f s tellen b o sch t he in cid en ce o f p e n a ltie s f o r f o u l p l a y w a s lo w e r in the ca se o f m a tch es h a n d led by tw o referees. t w e n ty five first league m atches p la yed in the second sem ester of 1990 at the u n iv e rsity o f stellenbosch w ere ra n d o m ly m o nitored. seven hostel m atches are u s u a lly p la yed on a f rid ay afternoon. f o r the p urpose o f this in ­ vestigatio n , four o f these m atches w ere co n tro lled b y a single referee and three b y tw o referees. a p ool of 12 first league referees w as used in the in v esti­ g ation. t h e y w ere appointed for all the m atches p rio r to the begin n in g of the semester. o w in g to w ith d raw als due to illness and o th er com m itm ents, altern a­ tive referees had to be used on som e oc­ casions. t he referees w ere not inform ed about the purpose of the investigation but w ere to ld th e y should experim ent w ith refin in g the system of double re­ fereeing. t h is, how ever, did not w o rk because the referees soon becam e aw are that th eir gam es w ere being m onitored for the p urpose o f co m p arin g the tw o system s. students in th eir final y e a r of hum an m ovem ent stud ies w ere used on a v o l­ u n ta ry basis to m o n ito r the m atches. b ecause it involved a fair am ount of com m itm ent, o n ly a few students w ere used. t w o students w ere assigned to each m atch, one being so le ly reponsible for reco rd in g and p la y in g tim e w h ile the o th er recorded all the o th er in fo r­ m ation. a s o n ly trained students w ere inv olved in th is in v estigatio n , sub sti­ tutes co uld n o t be used w h en som e of these studen ts w ere un availab le due to illn ess or o th er com m itm ents. t his had an adverse effect on the num ber of m atches recorded. t he students received verb al as w ell as w ritten instru ctio ns regard in g the re­ c o rd in g p ro ced ures. a fte r these had been discussed w ith them , th ey o b ­ served a video re co rd in g of a p rovincial ru g b y m atch. t he tape w as stopped at v ario u s stages to m ake sure that the stu ­ dents un dersto o d the pro cedure. the use o f the d ata sheet w as tested b y the m ain au th o r on three occasions before it w as finalised. selected resu lts are presented in table 1. the incidence o f penalties for foul p la y w as lo w e r in the case of m atches handled b y tw o referees. a l­ though this difference w as not stat­ is tic a lly sign ifican t (t = 0 ,4 6 2 ; p > 0,05) note sh o uld be taken o f the sm all num ­ ber of p enalties aw ard ed . h ow ever, it m u st be pointed o ut that the durations of these gam es w as 60 m inutes only. t he absence o f statistical difference is d icussed at the end o f the paper. q u estio n n aires w ere d istrib u ted am ong coaches, first league p layers, first league referees and supporters (p referab ly com m ittee m em bers o f the hostel club s). r espondents had to in d i­ cate th eir preference for a system of single referees o r tw o referees. in an open ended qu estio n th ey had to p ro ­ pose p ossible advantages and d isad van ­ tages o f a system o f do ub le refereeing. 4 --------------------------------------------------------------------------------sports medicine vol. 6 no. i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) space w as also p ro vid ed fo r an y general com m ents. the results are presented in table 2. it can be co n clud ed that a great m a­ jo r ity of p la y e rs, coaches and su p p o rt­ ers w ere in favour of the system of do ub le refereeing. f o u r of the 12 first league referees ind icated th at w ith re­ gard to p ersonal en jo ym en t and satis­ faction, th ey w o u ld p refer han dlin g m atches as a sin gle referee. h ow ever, all the referees are o f the opinion that the system o f do ub le refereeing w o u ld be in the best interest of the gam e. a ll tw elve referees w ere, therefore, in fa­ v o u r o f the system o f tw o referees. t he p erceived advantages of a s y s ­ tem of do ub le refereeing are presented in table 3. it is sign ificant to note that a to tal o f 90 respondents o ut o f a possible 135 stated that a system o f do ub le re­ fereeing w o u ld decrease the incidence o f foul play. a ll the r e fe re e s are o f the opin ion that the system o f d ou b le re fe re e in g w o u ld be in the b est in terest t a b le 1 : comparison between matches handled by a single referee and matches handled by two referees s in g le re fe re e n = 1 3 tw o re fe re e s n = 1 2 m (sd) m (sd) penalties for playing ball on the ground, obstruction and high tackles players in coolbox players sent off 2 (2,1) 0,07 0 1,6 (1,4) 0 0 t ab le 2: preferences for a referees system of single or two in fa v o u r a g a in s t total referees coaches players supporters 12 3 87(85%) 16 0 0 17(15%) 0 12 3 104 16 total 118 17 135 o f the g a m e. o p p o sitio n to the system of tw o re­ ferees are u sa lly based on the fo llo w in g argu m en ts: • too m uch w h istle w o u ld lead to an increase in stoppages and w ill nega­ tiv e ly affect the flo w o f the gam e. • r eferees w o u ld get in the w a y of p la yers. a lth o u gh the o n ly statistical difference betw een the tw o system s w as found in the n u m b er o f p enalties aw arded for off-side at the lin e-o u ts (t = 2 ,4 4 ; p < 0 ,0 5 ), there w as no evidence to su p p o rt the above argum ents. t he fact that tw o referees have been used over the past three seasons at the u n iv e rsity o f stellenbosch could have co n trib u ted to the absence of statistical t ab le 3 : perceived advantages of a system of two referees decrease in the incidence of foul play (90) infringements identified more effectively (50) better control of the game (36) greater impartiality and objective decision making (24) more flowing rugby (14) deliberate infringements prevented (14) off-side law applied more effectively (9) decreased incidence of injuries (5) improved standard of refereeing (3) referee less in way of players (1) referee less involved with spectators (1) creates a feeling of trust between referee and players (1) differences. p la y e rs -m a y have becom e accustom ed to the system and p layed the gam e in a m ore discip lin ed m anner regard less o f w h eth er the m atch was co n tro lled b y one referee or tw o re­ ferees. a case in p o int is the fact that the inciden ce o f foul p la y has decreased d ra m a tic a lly over the past tw o years. the num b er o f first league matches p layed in the hostel league is approxi------------------------------------------------------------------------------------------- 5 sportsgeneeskunde vol. 6 nr. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m a te ly 100 per season. in the 1989 sea­ son not a single case of foul p la y w as re­ po rted to this com m ittee. t he law s of the hostel league do not allo w the re­ feree an option and m ake it m an d ato ry for him to o rder a p la y e r from the field if he k ick s, tram ples or hits an appo nent, regard less o f the seriousness of such action, m ak in g this absence o f d is­ c ip lin a ry actions even m ore rem arka­ ble. t his w as c e rta in ly not the case a few seasons ago. w h ile the stystem has been func­ tio n in g for three y e a rs at the u n iv ersity of stellen b o sch , it is still in its infancy. the p o ssib ilitie s, however, have not been exploited and a great deal of refinem ent is still needed. a t this stage the system is not b eing used v e ry econ­ o m ic a lly since the d ivisio n of lab o u r be­ tw een the tw o referees is not being u til­ ised to the full. to date the system has functioned m o stly w ith both referees d ou b le r e fe r e e in g w ill d ecrea se the n u m b er o f in ju r ies th at a re a resu lt o f f o u l play. k eep in g the p la y b etw een them and m ore o r less lo o k in g at the sam e action from differen t angles o r view points w ith a lim ited divisio n o f labour. it is envisaged th at o th er m odels could be experim ented w ith , such as a system sim ila r to that used in b asketball. o ne of the local referees, for exam ple, handled a to u gh n o n -u n iv e rsity m atch w ith a co lleague in a n eigh b o u rin g town and reported that w hen tem pers began to flare one referee to o k control and handled the m atch in the no rm al w a y as a sin gle referee. h is colleague w as now co m p letely free to “lo o k for the tr o u b le ”. h e w as n o t concerned w ith the tech n ical aspects of the gam e b ut fo­ cussed his to tal attention on one specific aspect, n am ely the cause of the tro u b le. in fact, he id en tified the cu l­ p rit, o rdered him off the field and the gam e proceeded in an o rd e rly fashion. t h is in cid en t is an exam ple o f the p o ssi­ bilities in such a system . it w o u ld be naive to believe that do ub le refereein g is go ing to solve all pro b lem s and w ill c e rta in ly not prevent all ty p e s o f in ju ries. h ow ever, it is our firm b elief th at it w ill at least decrease the n u m b er o f in ju ries that are the re­ su lt o f foul play. t his b elief is based on com m on sense and on the subjective and o b jective o bservations m ade over the p ast three years. la wo reliable specialists infrared lasers al 609/4 easy handling and exceptionally effective! the modulation is carried out by the polyfrequency spec­ trum, which contains all frequencies up to 50 000 hz. the uncomplicated technology m akes this a softlaser for every kind o f treatment. a l 605/4 and a l 606/4 pre-programmed frequencies fo r the specialist! two sofitlasers are available for the classical ear acupuncture according to dr. n ogier: a l 605/4 containing the original n ogierfrequencies; al606/4 has been equipped with the augmented n ogier frequencies. the frequencies in both units can be varied by 30 %. al 607/4 high-tech fo r the professional medical practitioner this softlaser offers an unmodulated permanent beam (d) as w ell as the polyfrequency spectrum (p) up to 50 000 hz. a dditionally, every frequency between 0.1 and 9999 hz can be selected in the sinewave position (s ), w hich is assisted by a built-in crystal-controlled synthesizer. contact shirley godley at: la w o cc po box 95 noordhoek 7985 cape town tel (021) 89-2500 the concept o f la ser (light am plification by stimulated emission o f radiation) w as first discovered by albert einstein in 1916, but it w as not until 1950 that downs and shylaw first worked on e instein's theory to produce a crude form of laser which culminated in the building o f aproper one by meimon in 1960. the devices constructed today are sophisticated masterpieces o f m eim on's original and consti­ tutes the most exciting aid in medical and veterinary sciences today. lasers fall into two categories nam ely hot lasers used in surgery and cold lasers used in m uscular-skeletal problems, ie. h elium , neon and g allium a lum inium arsenide d iox­ ide. the lawo infrared laser is not only used extensively in beauty treatment, but also b y dentists, practitioners o f acu­ puncture, race horse breeders and physiotherapists, medical doctors and farmers. m ore in form ation ab ou t th e lawo l aser ca n b e ob ta in ed f r o m s hirley g odley, m a n a gin g d ir e c t o r o f lawo g eratebau in south a frica at telep h o n e (021) 89-2500 o r fa x (021) 89-1251. the laser is an anti-inflam m atory, decongestant, aseptic, plairiless red healing ligh t, portable and needs no direct power supply. human treatment bones, muscles, jo in ts, nerves, wounds, pain therapy, skin problems. 6 --------------------------------------------------------------------------------sports medicine vol. 6 no. i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiological profile of the senior south african rugby player jg barnard and ff coetzee i n t r o d u c t io n t he status of elitism in ru g b y is d eter­ m ined b y the standards achieved d u rin g the p artic ip atio n in the specific com pe­ titio n season, alth o ugh certain norm s of basic fitness com ponents could be use­ ful to reflect the status of the player. d u rin g the last decade standards have been raised in in tern atio n al sports w h ich necessitate a greater un d erstan d ­ ing o f the attrib u tes re q u ired to p ro ­ duce o u tstan d in g perform ance. a fu r­ th er scien tific tech n ique that can be of assistance in p la y e r developm ent is th a t o f p ro filin g . c u rre n tly m a n y detailed p h y sio lo g i­ cal p ro files exist o f athletes w h o p a rtic i­ pate in a w id e v a rie ty o f sp o rtin g activ­ ities. a lth o u g h ru g b y is o u r n atio nal sp o rt, a dearth o f inform ation exists w ith respect to the p h ysio lo g ical ch aracteristics o f south a frican ru g b y p la y e rs. c o m p ariso n s o f test scores b y an y p la y e r w ith d ata from a n orm ative base elite p la y e rs enable strengths and w e a k ­ nesses to be id en tified . selections and pro gram m es sh o uld then be structured th at tak e in d iv id u al p la y e rs ch aracteris­ tics into co n sideratio n . j g b a rn a rd a n d ff c o etz ee d ep a rtm en t o f p a ra m ed ica l s cien ces t echn ik on ofs p r iv a te b ag x20539 b lo e m fo n te in 9300. p u r p o s e o f t h e st u d y t he aim o f this stu d y is to b u ild up a n orm ative d ata base w h ich should be used for p ro filin g p u rposes. p r o c e d u r e s subjects t his stu d y w as conducted over a period o f five ru g b y seasons (1981 1986). o ne h u n d red and seven sen io r p la yers (54 fo rw ard s and 53 backs) w ere se­ lected for this p ro ject represen tin g the best and second best team (c u rrie c u p w in n ers and ru n n er-u p ) for th at p a r­ tic u la r season. methods a u n iversal test b attery w as therefore developed w ith respect to the anthro p o m etrical, p h y sio lo g ic a l and m o to r ch aracteristics. t his test b atte ry com ­ p risin g sop h isticated electro n ic eq u ip ­ m ent w as designed and tested for re li­ a b ility and v a lid ity .4 w ith in 10 d ays after the c u rrie c u p final the w in n in g team w as tested. the p ro ced u re w as as fo llo w s: to register the nam e, age and p erform ance h isto ry of the p la y e r ; to d eterm ine standing h eig h t; b o d y m ass; v ital cap ac ity and forced e x p ira to ry volum e in one sec­ o n d ; an th ro p o m etrical m easurem ents for the determ in atio n of so m atotypes by the h e a th -c a rte r2 m ethod as w e ll as relative b o d y fat3; isom etric strength (grip and b ack ); iso kin etic strength (quadriceps/ham strings, b i­ ceps/triceps); sp rin t (electro n ical tim ­ ing o f 5 in term itten t m eter distances to a to tal of 23 m ); h o rizo n tal p o w er; o b liq u e step sp rin t (vertical disp lace­ m e n t); v ertical p o w e r; hip fle x ib ility (h a m strin g s); target th ro w in g (hand e y e co o rd in atio n ); e q u ilib riu m (stabi lo m ete r); p la te tap p in g (h o rizo n tal arm m ovem ent) and endurance ( v 0 2nux p re ­ d icted b y the in d irect 12 m in c oopers m ethod). t he final test b attery catered for 8 an thro p o m etrical m easurem ents, 3 p h y sio lo g ic al m easurem ents and 12 m o to r function tests. the average values o f the m easured , as w ell as the calculated variab les are given in table 1. results and discussions d etails o f the p h y sio lo g ic al, anthropo­ m etric and m o to r function test results are p resen ted in table 1 w ith means o f standard deviatio n s for the forw ards and b ack -lin e groups. body composition f o rw ard s differed sig n ific a n tly (p < 0,05) from backs in that th e y w ere taller (189 cm vs 177 cm ), h eav ier (101 k g vs 79 k g), had h ig h e r relative b o d y fat (15% vs 9 % ) and greater lean b o d y mass (86 kg vs 71 kg). a s w o u ld be expected, these fin d in gs are because o f the differ­ ent specific resp o n sib ilities required of the tw o groups in th eir respective p la y ­ in g p o sitions. b o d y m ass is v e ry im p o rtan t to for­ w ard s in the set scrum s, m auls and ru cks. the h eavier the p ack of fo r­ w ard s, the greater w ill be the inertia, m om ent o f in e rtia, the s ta b ility o f the scrum and the m om entum (provided th at speed is not n eg ativ ely affected). t his supports the need for evaluation o f b o d y ty p e and p o sitio n al sta b ility of the fo rw ards. id e a lly a fro n t-ro w forw ard sh o uld be stro n g ly b u ilt, p a rtic u la rly in the back, shoulders and neck. ------------------------------------------------------------------------------------------- 7 sportsgeneeskunde vol. 6 nr. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r u g b y table 1: profile of the south african rugby player variable (units) rugby: forwards (n = 54) rugby: backs (n = 53) x s x s age (years) 23,9 3,1 23,6 2,7 mass (kg) 101,2 13,3 78,8 7,9 height (cm) 188,8 7,3 176,9 6,4 area (m2) 2,436 0,185 2,089 0,142 vital capacity (1) 6,8 0,7 5,7 0,9 vc/fev,(%) 84,0 5,8 83,7 7,3 body density 1,068 0,014 1,078 0,008 body fat (siri) 15,0 6,8 9,2 3,1 endomorphy(cor) 2,8 1,12 2,1 0,61 mesomorphy 6,6 1,1 6,0 0,9 ectomorphy 3,4 1,3 2,3 0,6 grip strength (kg) 76,7 10,9 67,9 8,8 back strength (kg) 217,1 30,9 185,5 34,1 knee extension (kg.m) 29,7 5,9 27,7 6,2 knee flexion (kg.m) 19,3 3,3 16,4 3,5 elbow flexion (kg.m) 5,8 1,0 4,6 0,8 elbow extension (kg.m) 8,0 1,8 6,8 1,3 sprint 0-23 m(s) 3,6 0,1 3,4 0,1 margaria 0-2 m (s) 1,4 0,2 1,4 0,1 sit & reach (cm) 6,9 9,1 9,6 8,8 accuracy (15) 5,4 0,3 5,9 0,4 balance (s) 14,2 0,2 13,9 0,2 tap test (s) 8,4 0,2 8,3 0,1 cooper (ml.kg1.m in1) 51,2 0,7 53,9 0,6 where n = number x = mean s = standard deviation the higher relative body fat of the fo rw ard s m a y be an advantage because it acts as a buffer d u rin g b o d y contact, w h ile the fo rw ard s are subjected to far m ore b o d y contact than the back-line p la yers. h ow ever, the negative co rre­ lation betw een b o d y fat and m otor fitness test scores are also v e ry im p o rt­ ant. b o d y contact is a significant aspect of rugby. r e la tiv e ly large b o d y size is im p o rtan t, though m ore im portant for som e positions than others. the large b o d y size o f the p la y e r is a d efinite asset w hen co n sid erin g b o d y m om entum and b o d y contact, provided that the higher relative b o d y fat does not in ter­ fere w ith velo city to the extent that it ad versely affects m om entum . a ge t he average age (23,8 y rs) of the group was o ld e r than m ost o th er national or p rovincial team s. as in other sports, it n a tu ra lly takes tim e for p layers to de­ velop th eir m axim al po ten tial. because of th eir increased v u ln e ra b ility to in ju ry through lack o f strength and/or inex­ perience y o u n g p la yers (un d er the age of 21 y e a rs) should be pro h ib ited from p la y in g ru g b y at senior level. m u s c u la r s t r e n g t h a n d p o w er s ign ifican t differences betw een for­ w ards and backs w ere found for the peak v o litio n al handgrips strength, and back strength (as there is a relationship betw een b o d y size and strength). g rip strength is v ery im p o rtan t to ru g b y p layers (backs and fo rw ards) w ho need it w hen b inding in the scrum s, rucks and m auls o r w hen han dlin g the ball. back strength is a n ecessity for the ru gb y forw ards in the scrum s, rucks and m auls. n o sign ifican t differences w ere found betw een the absolute knee flexion and extension po w er as dem on­ strated b y th e c y b e x . f le x ib ility a sit and reach test w as used to assess ham strin g m uscle group and low er back flexib ility. d ata differed sig n i­ fican tly betw een the tw o groups. an adequate level of fle x ib ility is im portant w hen forced to stretch and to prevent in ju ries to m uscles and associated tis­ sue. a n a e ro b ic p o w e r n o sign ificant difference w as found be­ tw een the tw o groups for the 23 m etre sp rin t or the m a rg aria test. as the m ar garia test w as sim ilar in both groups the d ifference in p o w er scores w as caused b y the differences in b o d y w eigh t. d e­ spite th eir greater w eigh t, the forw ards w ere able to run as fast as the backs, w hich d em onstrates th eir leg power. a ero b ic c a p a c ity the aerobic cap acity tests includes v 0 2 m„ values derived from the 12 m in ­ ute c o o p er test. the v 0 2max values of this stu d y (m ean 52,5 m l. kg ', m in '1) are sim ila r to those of the b ritish ru gb y p la y e rs .4 values reported for other sa e lite in term itten t-sp o rt athletes in d i­ cated (table 2) that professional soccer, squash and field h o ck ey p layers exhibit greater aerobic cap ac ity than the ru gb y p la yers. d o c h erty5 has p ostulated that the aerobic versus anaerobic en ergy de­ m ands of a ru g b y p la y e r gam e v ary be­ tw een 85% and 15% and depend upon the p la y in g po sitio n . p layers spend ap­ p ro x im a tely 85% o f their tim e in low in ten sity ac tiv ity and 6% of the 15% (intense a c itiv ity ) is related to running and 9% to activ itities such as com peting for the ball ta ck lin g and p ushing. this indicates that the gam e is m ore an aer­ obic than aero b ic, sugg estin g the need for a greater em phasis on anaerobic fitness train in g. a cco rd in g to these authors train in g should focus on d evel­ o ping the p o w er of this m etabolic path8 -----------------------------sports medicine vol. 6 no. i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r u g b y table 2: body composition and v 0 2max: a comparison between the sa senior rubgy player and data for sa elite athletes in other intermittent activity sports study age (yrs) height (cm) weight (kg) body fat (%) vo2m„ (m l.kg’ .mirr1) sa rugby 23,8 188,2 90,2 12,5 52,5 n=107 hockey6 21,5 178,4 72,0 9,9 54,1 n= 28 squash6 25,7 179,4 75,3 8,6 58,8 n= 18 soccer6 21,8 174,8 72,0 9,2 55,2 n= 36 w a y since o n ly a few activites seem to extend b eyo n d a 10 second duration . t he ratio of p la y in g tim e and recovery tim e should be considered because their inten sity o f effort is esp ecially d e­ pendent on the a b ility to recover from anaerobic d u rin g the aerobic recovery phase. a erobic co n d itio n in g should therefore be em phasized. m u lt iv a r ia t e a n a ly s is a m u ltiv ariate an alysis used to com pute the findings of 725 m ales particip atin g in 28 categories represented b y 20 sports in south a frica sum m arize the fo llo w in g results that are im portant for ru g b y : the ru g b y -fo rw ard s scored the best in elbow flexion and backstrength the poorest in v 0 2m„ and relative k neeflexion and extensions and the highest in m esom orphy. c o n c lu s io n t his paper dem onstrates the use of ac­ tual p rofiles stru ctu red from m o rpho­ logical, m o to r fitness and p h ysio lo gical d ata in assisting the coach, selector or the ru g b y p la y e r to im prove the latte rs’ p la y in g ability. it should be em phasised that the authors do not believe in a single en tity o f p h y s ic a l fit n e ss. r u gb y d e­ m ands a different co m bination of func­ tio n al capacities and therefore, the fitness of an in d iv id u al must be specific to the p artic u lar task in h a n d .5 these norm s can be used to predict, w ith in lim its, aptitude for p artic i­ pation and to reflect shortcom ings in specific fitness com ponents, as w ell as im provem ent, th ro ugh specific training program m es. r efer enc es 1. d e s p ir e ’s m , b a rn a rd j g , g e ld e rb lo m ij a n d f e r r e ir a s. s p e s if ie k e m o to rie s e en fik s h e id s k o m p o n e n te b y s p o r tlu i. sa t y d s k n f v i r n a v o rsin g in s p o rt, l ig g a a m h k e o p v o e d k u n d e en o n s tp a n n in g , 3(1): 7 1-8 8 , 1980. 2. heath bh and c a rte r je l . a m odified so m a to typ e m ethod. a m j p h y s a n th r o p , 2 7 : 5 7 -7 4 , 1967. 3. siri w e . b o d y co m p o stio n fro m spaces and density, d o n n e r l ab o rato ry, medical p h y s ­ ics (u n iv e rity o f c alifo rn ia), 1956. 4. w illiam s c , reid r and c au tts r. o b s e r­ vation o f the aerobic p o w e r o f un iversity ru g b y p la y e r and p rofession al soccer player. b n tj s p o r ts m ed : 7: 3 9 0 3 9 1 , 1973. 5. d o c h e rty d , w enger h a and n eary p. t im e-m o tio n analysis related to the pysio logical dem ands o f rugby. j o u r n a l o f h u ­ m a n m o v e m e n t s tu d ie s, 1 4 : 2 6 9 2 77, 1988. 6. d e sp ire ’s m . n ation al research project n o 1. the q u an tificatio n o f variables c o n trib ­ uting to p erform an ce in top s p o rt in the r sa . u o f s , b lo em fo n tein , 1988. a . \ w la < > ---------------------------------- 9 sportsceneeskunde vol. 6 nr. i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports injuries encountered o n a five week international cricket tour ca smith a b s t r a c t ... .......... " ........... " ........ ~ ~ ' ......... ..... ’ ’ ] ! ' i i i k e y w o r d s : c rick et, i n ter n a tio n a l tour, co m m o n in juries, p h y sio th e ra p y i j i i the injuries incurred by 16 international cricketers while on a 5 week to u r have been recorded. the physiotherapy treatm ent fo r these injuries has also been briefly noted. the purpose o f this article is to make | ’ the medical team m anaging a cricket team (or any tou rin g sports team) m ore aw are o f the type and extent o f | com m on injuries to be expected on a tour. it was concluded th at it is im p ortan t to th o ro u g h ly screen each | player before undertaking an y tours o f this n ature to identify either present o r past injuries. therefore, a i i treatm ent/training program m e fo r the players, w ith the aim of minimising the possibility o f re -in ju ry while ! on tour, can be advised. j in tr o d u c tio n t here is a con siderable am ount of lite r­ ature discussin g the com m on injuries associated w ith different elite sp o rts­ m en and th eir sp o rtin g a c t i v i t i e s . 4 h ow ever, the lite ratu re p ertain in g to the ty p e and extent of in ju ries incurred w ith sports team s w hen on to u r is sc a rc e .5 m o re specifically, although a fair am ount of p u b lish ed research on c rick et as a sport does e x ist,6’7,8’9’10 there is little evidence d escrib in g the injuries w h ich can be expected w ith a to urin g intern atio n a] c ric k e t team. t herefore, the aim o f this stu d y w as to h ig h ligh t the com m on in ju ries associated w ith an ca s m ith bsc p h y sio th era p y bsc (h ons) s ports s cien c e u ct/mrc b io e n e r g e tic s o f exercise r esea rch unit u c t m ed ica l s ch o o l o b s e r v a to r y c ape town. in tern atio n al cricket team w h ile on tour, and thus assist w ith the p la y e r’s p rep aratio n for future such tours. b a c k g r o u n d sixteen in tern atio n al cricketers visited south a frica on a 5 w eek tour, w hich included 1 five d a y test m atch, 4 one d a y intern atio n als and 3 three d a y p re ­ lim in a ry m atches again st provincial team s in south a frica. p rio r to d ep artin g from th eir hom e country, each p la y e r u n d erw en t a p h y sic al fitness exam ination. the exam in atio n consisted of m uscle po w er testing on a cyb ex , m easurem ent of o x­ y g e n u p tak e w h ile p ed allin g on a cycle ergo m eter and an increm ental running speed test on a tread m ill. each p la y e r w as also exam ined b y a p h y sio ­ th erap ist, and in som e cases an o rth o ­ p aedic p h ysicia n . u n fo rtu n ately, the testing w as done too close to the tim e of d ep artu re, and the p la y e rs never had sufficient tim e to im prove the areas of fitness in w h ich th ey w ere considered w eak . the c ric k e te rs’ o w n dom estic season ended in septem ber 1989 and to u r took place four m onths later in j a n u a r y 1990. the off-season b reak m eant that p la y e rs w h o did not m ain tain a reason­ able stan dard of fitness over this period did n o t start th e to u r in th e p h ysical co n d itio n th ey w o u ld have been in, had the to u r been clo ser to the end of th eir p la y in g season. a lth o u gh this could have co n trib u ted to som e p la yers in c u r­ rin g in ju ries e a rly on in the to u r w hen th e y w ere still not fu lly fit and con­ d itio n ed , it c o u ld also have w o rk ed in the team ’s favo u r b y assisting some p la y e rs to reco ver from a n y in ju ry of the p rev io u s season. exercise a n d tr a in in g regimen a fter arriv in g and before com m encing w ith the first m atch, the team had 6 d ay s t o a cclim a tis e t h e m s e lv e s t o the su rro u n d in g co n d itio n s, to increase th eir suppleness and flexib ility, th eir gen eral level of fitness and im prove th eir crick etin g sk ills, ie. b attin g, b o w l­ ing and field in g. from the b eginning, em phasis w as placed on stretching and w arm in g-u p e x e r c is e s b e f o r e th e p r a c ­ 10 --------------------------------------------------------------------------------sports medicine vol. 6 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) tise sessions and m atches, w ith the aim of keep in g the in ju ries on to u r to a m in ­ im um . p ractise sessions d u rin g the first w eek n o rm ally lasted b etw een 2 to 3 h o urs, som etim es tw ice daily. the ses­ sions started w ith a slo w w arm -u p jo g of 2 to 3 laps aro u n d the p la y in g field. t his w as then fo llo w ed b y stretching exercises fo r about 20 m inutes (the b i­ ceps, tricep s, d elto id s, trap ezii and la tissim us d o rsi, qu ad ricep s, h am strings, g lu te ii, thigh abductors and adductors, the calf and abd o m in al m uscles). m o ­ b ility exercises fo r the sh o u ld er and hip jo in ts as w e ll as the entire spinal colum n w ere also perform ed. stren gth en in g exercises, m a in ly for the leg, ab do m in al and sh o u ld er girdle m uscles w ere then done. these in ­ cluded sit-u p s, leg th ro w -d o w n s, leg a n ti-g ra v ity exercises and press-ups. short sprints and m edium distance runs at 50 and 75% of m axim um w ere also perform ed. t he p layers then w en t to the nets to im prove th eir b atting and b o w lin g sk ills and finished off w ith field in g practise. u n d e r l y in g in ju r i e s o n a r r iv a l several p la y e rs arrived w ith u n d erlyin g in ju ries. som e in ju ries w ere a resu lt of the p revious crick etin g season and others w ere of a m ore chronic lo n g ­ stan d in g n ature. a lth o u gh som e of the in ju ries w ere not as a d irect cause of the tour, th e y w ere aggravated b y the to u r’s inten se p ro gram m e, and thus w a r­ ranted treatm en t. f u rth erm o re, som e u n d e rly in g co nditions w h ich w ere re­ po rted rem ained asym p to m atic th ro u gh o u t the d u ratio n of the to ur and n ever req u ired treatm ent. a ll the u n d e rly in g in ju ries w ere assessed and repo rted b y the p h ysio th erap ist w ho had screened the p la yers p rio r to th eir dep artu re and w ere w ritten up in a short report for each player. some p la y ­ ers w h o had m ore serious in ju ries w ere also exam ined b y an orth o p aedic su r­ geon. o ne p la y e r had had a rig h t knee ar­ th ro sco p y in 1989 for an osteochondral lesio n , and had recovered from this over the off-season. h ow ever, the in ­ ju r y w as re-aggravated in his first m atch, w h ich resulted in a syn o v itis. a fu rth er tw o w eeks of rest and treatm ent w as n ecessary before he could resum e p la yin g . a n o th er p la y e r w as found to have “gross degeneration of the left h ip ” on x -r a y coupled w ith a slig h t fixed flexion d efo rm ity and restricted abduction and m edial and lateral ro tatio n . these signs w ere not o v e rly relevan t, and the p la y e r o n ly dem o n strated m oderate in fle x ib il­ it y at the hips w ith stretch in g exercises. h e n ever com plained of pain o r d is­ com fort d u rin g exercise and w as able to p la y in all the gam es for w hich he w as selected. a n o th er p la y e r com plained of lu m ­ bar backache and stiffness. h is m edical report attrib u ted this to the presence of a 6th lu m b ar verteb ra w ith conse­ q u en tial loss of the no rm al lord o tic curve. m o b ility and stretch in g exercises fo r the th o raco lu m b ar region w ere given to the p la y e r to ensure he re­ m ained asym p to m atic. o ne of the b o w lers presented w ith a m in o r facet jo in t neck in ju ry w hich re­ covered w ith in the first w eek fo llo w in g m o b ilisatio n treatm ent. a n o th er p la y e r arrived w ith a h is to ry of a chronic righ t achilles ten d in itis. r e g u lar stretching helped keep the co n ditio n pain free u n ­ til the last w eek of the tour, but then team selection rath er than the in ju ry p revented the p la y e r p la yin g . l astly, one of the b o w lers had an asy m p to m atic un stab le osteitis pubis w h ich revealed a 1,5cm depression of the left p ubic ram i. h e insisted that it never tro u b led him w hen he bow led, and this rem ained tru e for the d u ration of the tour. in ju r i e s a n d p h y s io t h e r a p y t r e a t m e n t a to tal num b er of 40 separate injuries w ere recorded on the to u r (table 1). t here w ere 8 m uscle in ju ries, 6 inv olv­ ing tendons, 5 ligam en ts sprains, 14 af­ fecting eith er bone or jo in t stru ctu res, 3 to n eu ral tissues, 3 to soft tissues and 1 o th er in ju r y in v o lv in g none o f the above structures. t here w e re 24 m in o r and 16 m ajor in ju ries. m in o r in ju ries w ere con­ sid ered to be those w h ich to o k 3 treat­ m ents or less to recover and w hich did not rule a p la y e r out from team selec­ tion. m ajo r in ju ries w ere those w hich w arran ted m ore than 3 treatm ents and m igh t have prevented a p la y e r from p la y in g . a ll 16 in d iv id u als w ere treated w ith 166 treatm en t sessions in to tal given, at an average of 10,4 sessions per player. treatm ent m o d alities included electro­ th erap y ap paratus (in terferen tial, u ltra­ sound and laser), m anual p h ysio ­ th erap y techniques (m o b ilisatio n s, m assage, exercises and tap in g p ro ­ cedures) and lastly, ice. in to tal, 405 treatm ent m o d alities w ere used in the 166 attendances, at an average of 2,5 m o dalities p er session. the m ost com ­ m on m o d a lity w as u ltraso u n d , fo l­ lo w ed b y m assage, laser, m o b ilisations, ice, in terferen tial, strap p in g and exer­ cises being used least. muscle injuries t w o p la yers w ere treated w ith deep m assage fo r m uscle scarrin g and m ech­ anical tension in th eir sh o ulder girdle regio n . t hree p layers strained their quadricep s m uscle, tw o of them being m ild grade one strains w h ich responded to transverse friction treatm ent, the th ird tak in g slig h tly longer to heal as the p la y e r had p rev io u sly torn the m us­ cle. t w o h am strin g inju ries w ere in ­ cu rred , both the result o f old injuries being re-aggravated . since the one p la y e r filled a k e y position (w icket keep in g) w hich kept p u ttin g strain on the m uscle and p layed in all the m atches, he did not have adequate tim e to rest and thus the in ju ry never healed com pletely. the o th er ham strin g in ju ry o n ly presented to w ards the end of the to u r and d id not lim it the p layer to m u ch extent. both w ere treated w ith cross friction m assage, ice, straigh t-leg raise stretching, ultraso un d and laser therapy. the last in ju ry w as a m inor strain o f the calf m uscle w h ich re­ sponded to 2 treatm ent sessions of transverse frictions and ultraso un d. tendon injuries t he com m onest tendon injuries on t h e . to u r w ere fo u r groin strains, all of ------------------------------------------------------------------------------------— 11 sportsgeneeskunde vol. 6 nr. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) [s3] r elifen 500 tablets 500 m g n abu m eto ne. r eg . no . r /3.1/265. n ab u m eto n e. s m ith k line b eecham p h arm aceu ticals p o b ox 347 b ergvlci 2012 w hen y o u r p a tien t’s in pain, y o u r first resp o n sib ility is to take a w a y that pain. q u ic k ly . e ffectively. but doing so could lead to unacceptable gastro­ intestinal side effects and com binatio n th erap y. b ut n o w , ten years of p recisely targeted m o lecular research have produced a h ig h ly effective, no n-acidic an ti-in flam m ato ry. r elifen. each tablet is m ade of 500 m g nabum etone, a n o n-steroidal an ti-in flam m ato ry, proven in num erous double blind studies to be as effective as o th er benchm ark n sa id s. yet its route o f action is to tally different. r elifen is a n o n-acidic p ro -d ru g. in the sto m ach , it is relativ ely inactive. it is absorbed from the duo den um , into the p o rtal blood su p p ly. f in a lly, in the liver, it is m etabolised into a potent in h ib ito r of prostaglandin synthesis. r efer p ackage in sert for fu ll p rescrib in g in fo rm atio n . f u rth e r in fo rm atio n is a v ailab le from o u r m e d ical d epartm ent. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) relieving his pain is pretty sporting of you, old chap. but do you have to get him high on acid? the active m etabolite penetrates the syn o v ial fluid to reach the inflam ed site, givin g effective relief of sym p tom s. e xcretion is b y the k id n ey s, so gastro ­ in testinal dam age th ro ugh b ilia ry recirculatio n and reflux is u n lik e ly . for effective relief from pain and inflam m ation, w ith less chance of g astro -in testin al d isco m fo rt, y o u now have an ideal choice. r elifen. relifen and the sb logo arc trad em ark s. p h a / og il vy & m at h er , ri gh tf or d se ar le -t ri pp & m ak in 34 9 83 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ; table 1: in tern atio n al touring c ric k e t injuries 1990. ; i n ju r y s ta tis tic s m uscles 8 tendons 6 , l igam en ts 5 i b ones/joints 14 i n e u ral t issues 3 j soft t issues 3 i o th er 1 ! t otal 40 p h y s io th e r a p y t re a tm e n t in d iv id u als treated 16 t reatm ents given 166 i treatm ent m o d alities e lectro th erap y: in terferential 21 u ltraso u n d 99 l aser 61 t otal 181 m a n u al: m o b ilizatio n s v ertebral 27 p erip h eral 33 t otal 60 m assage specific 78 n o n -sp ecific 5 t otal 83 specific exercises 14 strap p in g 16 ice 51 t o tal t re a tm e n t m o d a litie s 405 16 p la yers received 405 treatm en t m o dalities, average 25,3 405 m o d alities in 166 treatm en t sessions, average 2,4. w h ich involved the adducto r longus tend o n o n th e left leg close to the ischial tu b e ro sity insertio n . t w o occurred e a rly on in the to u r and responded w ell to treatm en t w ith transverse frictions, u ltraso u n d and laser w h ile th e' other tw o occurred in the final w eek and had not fu lly healed b y the tim e the tour w as over. o ne p la y e r had a sm all gan ­ glion of his ab d ucto r p ollicis brevis ten­ don o f th e e ig h t w rist. it to o k 5 s e s s io n s of laser and ultraso u n d th erap y coupled w ith an ti-in flam m ato ry m edication to relieve the pain. l astly, one p la yer p resented w ith a grade one supraspina tus tend o n itis. t w o treatm ent sessions w ith frictio n m assage and laser cured this injury. l ig a m e n t in ju rie s t w o p la y e rs com plained o f pain in the area of the soft ligam entous tissues su r­ ro u n d in g the sac ro iliac jo in t. o th er l i ­ gam entous in ju ries included the ante­ rio r ta lar fib u lar ligam ent and nearb y extensor retin acu lu m , the m edial co r­ o n ary ligam en t of the knee jo in t and the co raco clavicu lar ligam en t of the sh o ul­ der. f rictio n m assage com bined w ith u ltraso u n d and laser w ere used in no m ore than 3 sessions to treat each of these injuries. b o n e/ jo in t i n ju rie s t hese w ere the m ost com m on injures observed on the to u r (table 1). f irstly, n ig g lin g in ju ries to the sp in al colum n o ccurred at three lev els; cervical and th o racic facet jo in t in ju ries in tw o p la y e r and lu m b ar facet jo in t pain and stiffness inv olvin g four others. the sp i­ nal in ju ries responded w ell to m o b ilisa­ tion and in terferen tial therapy. o n e o f th e c o m m o n e s t in ju ries in crick et, those in v o lvin g the fingers, w ere seen in three p la y e rs . a dislocated d istal interp h alan geal jo in t (d ip) of the little fin ger w as im m e d iately reduced and req u ired 5 d ay s rest and padded strap p in g u n til the p la y e r co uld p la y again. a n o th er p la y e r w as h it w ith the ball on the end of the little fin ger re su lt­ ing in an im p actio n in ju ry to the d ip jo in t and lateral d isplacem ent of the te r­ m in al phalan x, confirm ed b y x -r a y an alysis. t he jo in t w as padded, strap p ed and im m o b ilised . a local an aesthetic injectio n w as adm inistered after the p la y e r insisted on retu rn in g to the field. a h airlin e fracture of the m id d le phalanx of the rig h t index finger occurred in the th ird player. the finger w as im m m o b ilised and w e ll padded, but never healed in tim e and prevented the p la y e r from p la y in g again on the tour. t w o elb o w in ju ries w ere also o b ­ served ; firstly, n o n -lo calised p ain in the olecranon region w h ere the involved stru ctu re co u ld not be c le a rly identified responded w e ll to m o b ilisatio n treat­ m ent, and secondly, a cap su litis w h ich presen ted w ith lim ited jo in t m ovem ent, pain and effusion. t h is w as treated s y m p to m a tic a lly to reduce the pain and sw e llin g and the effusion w as to be as­ p irated if it h ad n o t settled dow n once the p la y e r had retu rn ed hom e. t w o su b p erio steal h aem atom as w ere the re su lt of tw o p la yers being struck b y the b all, one on the rad iu s and the 14 --------------------------------------------------------------------------------sports medicine vol. 6 no. i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) other on the tib ia. the sw ellin g in the forearm occurred in conduction w ith tendon crep itu s in the com m on exten­ so r d igito ru m tendons. t reatm ent con­ sisted of ice and ultraso u n d therapy. l astly, an u n d e rly in g o steochondral knee in ju ry w as re-aggrav ated on to u r and also p resen ted w ith a m ild effusion. the p la y e r needed tw o w eeks in itial rest and treatm en t before p la y in g again, and then fu rth er d a ily sym p to m atic treatm ent w ith in terferen tial th erap y and ice to reduce the sw e llin g and pain and enable him to p la y the o n e-d ay m atches. n eural injuries t hree in ju ries presen tin g w ith neural tissue signs and sym p to m s occurred in conjunction w ith or fo llo w in g o th er in ­ juries. these com prised of adverse m echanical tension and friction s y n ­ drom e o f the sciatic nerve in the lo w er buttock in tw o p la y e rs and an adherent lum bar nerve ro o t in the lu m b ar spine of another. t h ey w ere treated b y m o b i­ lising and stretch in g the n eu ral and co n ­ nective tissue elem ents. soft tissue injuries t w o p la y e rs developed soft tissue in ju ­ ries as a resu lt of b eing stru ck w ith the cricket ball. o ne p la y e r developed a para-n asal h aem ato m a on the side of the nose, and the o th er p la y e r developed a contusion on the calf. a n o th er p la y e r also had in term itten t pain in the gluteal region sim ila r to that of a g lu teal b u rsi­ tis. treatm ent w as confined to laser and ultraso un d therapy, but did not provide com plete relief of the sym ptom s. o th er injuries a su b u n gu al infection developed in a bowler, p a r tly from friction ru b b in g of the p la yers boot again st the toenail of the great toe. t he p la y e r m ade the necessary su rgical adjustm ents to his bo w lin g shoes and com bined w ith re l­ evant an tib io tic therapy, the infection had cleared up w ith in a w eek . c o n c l u sio n the in ju ries associated w ith 5 w eek in­ tern atio n al c ric k e t to u r have been presented. the p h ysio th erap y treat­ m ent w h ich w as adm inistered is d is­ cussed. t he n um ber of in ju ries encountered (40) m igh t be co n sidered high w ith re­ spect to the to u r’s d u ra tio n of 35 d ays. even so, 20% of these w ere as a result of re-aggrav ated in ju ries from the p re­ vious crick et season. t herefore, the 4 m onth b reak in b etw een the season and the to u r co uld have been b etter utilised to prepare the in d iv id u al p la y e rs, by gettin g them fit and therefore p rev en t­ ing an y recurrance of troublesom e in ju ­ ries. the to u r’s intense pro gram m e of 16 m atch d ay s and 14 practice d ay s m ight have co n trib u ted to a larg er volum e of in ju ries. t h is w as th o u gh t to have been prevented to som e extent b y the v ig o r­ ous stretch in g and w arm in g -u p ro u ­ tines w h ich preceded each practise ses­ sion and m atch day. the financial operation of a surgery can be a headache of major proportions. and to keep things from tailing apart you need more than a bookkeeper and a p.c. — with all the compromises inherent in generalised business software. you need a customised, single or multi-user system from noridata. not just because its more cost-effective than ordinary p.c.’s — but because its hardware and software are tailored specifically for your practice whether r efer en c es 1. j o h a n s s o n c . in ju rie s in eiite orienteers, a m ] s p o r ts m e d 19 8 6 , 14(5), 4 1 0 4 1 5 . 2. k e lle r c s. the m edical aspects o f soccer in­ ju r y ep id em io lo g y, a m j sports m e d 19 8 7, 15(3), 2 3 0 -2 3 7 . 3. sm ith f h . ice h o c k e y in juries, a m j sports m e d 19 8 7, 15 (1), 3 0 -4 0 . 4. l o w d o n b w . in ju ries to in tern atio n al com ­ petitive su rfb o ard rid ers, j sports m e d p hys f itness 1 9 8 7 ,2 7 ( 1 ) , 5 7 -6 3 . 5. w att j , b o tto m ly m b , and read m tf. o ly m p ic athletics m edical experience, seoul person al view s, b r j sports m e d 19 8 9, 2 3(2), 7 6 -7 9 . 6 . p ayn e w r , h o y g , and c la rs o n j s . w h a t research tells the cricket coach, sports coach 1 9 8 7 , 1 0 ( 4 ) , 17 -22 . 7. e llio tt b c , and f o ster d h . a biom echan i­ cal analysis o f the fro n t-o n and side-on b o w lin g techniques, j o u r n a l o f h u m a n m o v e m e n t s tu d ie s 1 9 8 4 , 10, 8 3 -9 4 . 8. lillee d k . ‘the a r t o f fast b o w lin g ’ c o l­ lins publishing c o m p a n y 19 7 7 , s y d n e y 9. e llio tt b c , f o ste r d h and g r a y s. b iom e­ chanical and p hysical f actors influencing fast b o w lin g , a u stra lia n j o u r n a l o f science a n d m e d ic in e in s p o rt 1 9 8 6 , 18 (1), 1 6 -2 1 . f o rw a rd g r . in d o o r crick et in ju ries, m e d j a u s t r m s , 1 4 8 (1 1 ) , 5 6 0 -5 6 1 . large or small — specialised, prescribing or dispensing. supported by a nearby practice management professional who has a world of experience in integrating computers with the medical profession. computers that are compatible with other systems and expandable in the future without changing software. for the name of that practice management professional (we have over 50 country-wide) call us at (011) 484-4392 now. just a 15 minute no obligation demonstration will show you how easy it is to manage your practice painlessly. medsolve south a frica's m ost used medical practice m anagem ent system . . . . . , a n d winner o f the c.s.a. 1990 silver aw ard f o r an exceptional established south a frican product. n o r id a ta d i v i s i o n o f n o r i s t a n l i m i t e d p o box 31469 braamfontein 2017 cure the biggest problem in practice management. sportsgeneeskunde vol. 6 nr. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) p h y s io t h e r a p y u p d a t e the physiotherapy treatment of a hamstring tendon injury in t h e p a s t f e w y e a r s p h y s i o t h e r a p i s t s h a v e n o t i c e d an in c re a s e in t h e n u m b e r o f p a t i e n t s c o m p l a i n i n g o f p a i n , “ h i g h u p , at t h e t o p o f m y leg u n d e r m y b u t ­ t o c k , an d w h e n i ’m r u n n i n g , i feel th a t if i p u t m y f i n g e r i n t o t h e p a in , it w i l l h e l p , b u t it d o e s n o t ”. t w o d i f f e r e n t age g r o u p s c o m p l a i n o f t h e p r o b l e m . t h e f i r s t is t h e g r o u p o f s c h o o l c h i l d r e n w h o p a r t i c i p a t e in p r o ­ v i n c i a l a th le ti cs . t h e y ar e o f t e n h u r d l ­ ers a n d s o m e t i m e s s p r i n t e r s w h o h a v e l o n g h o u r s o f t r a i n i n g . a s can be e x ­ p e c t e d , t h e m o r e c o m m o n age g r o u p w i t h m i n o r d e g e n e r a t i o n o f t e n d o n s d u e t o age, is th e g r o u p b e t w e e n 4 5 an d 5 5 y e a r s . t h e s e p a t i e n t s ar e u s u a l l y l o n g di s t a n c e r u n n e r s . t h e s c h o o l c h i l d p r e s e n t s a h i s t o r y o f an a cu te i n j u r y , u s u a l l y c a u s e d b y i n ­ a d e q u a t e o r i n c o r r e c t w a r m u p m e t h ­ o d s . t h e r e a s u d d e n o v e r l o a d o f the h a m s t r i n g m u s c l e , cr e a te s i m m e d i a t e p a i n in t h e a re a o f th e isc hia l tu b e r o s i t y . t h e o l d e r age g r o u p has a d i f f e r e n t h i s t o r y o f p a i n o c c u r r i n g g r a d u a l l y o v e r a l o n g p e r i o d o f r o a d r u n n i n g . b e c a u s e t h e p a i n m a y ra d i a t e d o w n t h e b a c k o f th e leg m a n i f e s t i n g in th e s i d e r m a t o m e , t h e p h y s i o t h e r a p i s t , d u r ­ ing h e r e x a m i n a t i o n , a l w a y s d i f f e r e n ­ tiates b e t w e e n an l5 /s 1 p r o b l e m an d a h a m s t r i n g i n j u r y . t h e n e r v e i n n e r v a t i o n o f t h e h a m s t r i n g s is s i . to d i f f e r e n t i a t e , o n e asks t h e p a t i e n t t o t o u c h his t o e s w h i l e k e e p i n g his k n e e s e x t e n d e d a n d f l e x i n g his hips. t h i s m o v e m e n t str es s e s t h e s t r u c t u r e s o f t h e l u m b a r s p in e . if t h e p a t i e n t r e ­ p e a t s th is m o v e m e n t w i t h his l u m b a r s p i n e e i t h e r f l a t t e n e d o r in a l o r d o t i c p o s i t i o n , t h e h a m s t r i n g m u s c l e is s t r e t c h e d . t h e r e ar e o f c o u r s e m a n y o t h e r e x a m i n a t i o n m o v e m e n t s w h i c h the p h y s i o t h e r a p i s t asks t h e p a t i e n t t o p e r ­ f o r m in o r d e r t o r e p r o d u c e t h e pai n. r e s i s t e d f l e x i o n o f th e k n e e s h o u l d r e ­ p r o d u c e t h e p a i n at t h e site o f th e h a m ­ s t r i n g t e n d o n , b u t d u e to t h e s t r u c t u r e a n d s i z e o f t h e m u s c l e an d t e n d o n , it d o e s n o t a l w a y s d o so. o n c e t h e p h y s i o t h e r a p i s t has d i a g ­ n o s e d t h a t t h e p r o b l e m is a h a m s t r i n g t e n d o n i n j u r y , t h e n th e t e n d o n is p a l ­ p a t e d a n d t r e a t e d w i t h t r a n s v e r s e f r i c ­ ti o n s . t h i s is a d e e p m a ss a g e w i t h the f o r c e at r i g h t an g le s t o t h e t e n d o n . it is a v e r y t i r i n g t r e a t m e n t f o r t h e p h y s i o ­ t h e r a p i s t a n d e v e n th e p a t i e n t u s u a l l y s y m p a t h i s e s . d i f f e r e n t el e c tr i c a l m o ­ da l i ti e s s u c h as u l t r a s o u n d an d l a z e r are a ls o u s e d in o r d e r to d e c r e a s e the i n ­ f l a m m a t i o n a n d e n c o u r a g e h ea li ng . in re s i s t a n t ca ses , if p h y s i o t h e r a p y d o es n o t i m p r o v e t h e c o n d i t i o n th e i n f i l t r a ­ t i o n o f t h e a re a w i t h a s t e r o i d i n j e c t i o n is the n e x t s te p o f f e r e d . t h e p h y s i o t h e r a p i s t d o e s n o t a l l o w t h e p a t i e n t t o p a r t i c i p a t e in s p o r t un ti l h e is p a i n f r e e a n d his h a m s t r i n g h a s r e ­ t u r n e d t o its o r i g i n a l s t r e n g t h , p o w e r a n d fl e x i b i l i ty . if a v a i la b l e , t h e p a t i e n t is t e s t e d o n an i s o k i n e t i c te s t i n g m a c h i n e in o r d e r t o a s c e r ta i n his q u a d r i ­ c e p s / h a m s t r i n g r a t i o s a n d p o w e r . h e is t h e n g i v e n a p r o g r a m m e o f i s o m e t r i c o r g y m n a s i u m e x e rc i s e s in o r d e r t o c o r r e c t his d e f i c ie n c i e s . t h e i s o k i n e t i c m a c h i n e its e lf , can be u s e d as a r e h a b i l i t a t i o n m a c h i n e as w e l l as a te s t i n g m a c h in e . o n c e he r e t u r n s t o his s p o r t , he can p r o t e c t t h e t e n d o n b y us in g a t h e r m a l s u p p o r t . t h e s e s u p p o r t s ar e m a d e f r o m a n y l o n n e o p r e n e an d ar e s i m i l a r t o a w e t s u i t m a t e r i a l , b u t ar e th in ne r. t h e y re t a i n t h e b o d y ’s n a t u r a l h ea t, e n s u r i n g a g o o d b l o o d s u p p l y t o t h e area. m o r e a n d m o r e t o p s p o r t s m e n are u s i n g these s u p p o r t s w h i c h ar e m a n u f a c t u r e d in s o u t h a f r i c a . t h e s p o r t s m a n w e a r s it b o t h w h i l e h e is p r a c t i c i n g a n d w h i l e he is p l a y i n g his s p o r t . it is a v e r y c h e a p a n d e f f e c t i v e f o r m o f p r o t e c t i o n f o l l o w ­ ing an i n j u r y a n d is a ls o a p r e v e n t a t i v e m e a s u r e . 16 -----------------------------sports medicine vol. 6 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) e x e r c is e -r e l a t e d in j u r ie s the prevention of exercise-related injuries among south african army recruits: a review h j v a n heerden in t r o d u c t io n t h e h i g h in c i d e n c e o f e x e r c i s e r e l a t e d i n j u r i e s , p r i m a r i l y in th e f o r m o f o v e r ­ use s y n d r o m e s t o th e l o w e r e x t r e m i t i e s , is a u n i v e r s a l p r o b l e m a m o n g r e c r u i t s b e i n g s u b j e c t e d t o an i n t e n s i v e p h y s i c a l c o n d i t i o n i n g p r o g r a m m e (ba sic t r a i n ­ ing) o n e n t e r i n g t h e m i l i t a r y s e r v i c e . 1'3 in this r e s p e c t a v a r y i n g i n c i d e n c e has b ee n r e p o r t e d , w i t h a m e r i c a n a r m y 1 an d m a r i n e 2 r e c r u i t s s u f f e r i n g a 2 6 % an d 3 7 % ra te o f i n j u r y r e s p e c t i v e l y , a n d th e n e w z e a l a n d 3 a r m e d f o r c e s d o c u ­ m e n t i n g an e x t r e m e 6 5 , 4 % in c i d e n c e o f “w o r k r e l a t e d ” in j u r i e s . t h e p o s s i b i l i t y t h a t a s i m i l a r s i t u a t i o n m a y e xi s t in the s o u t h a f r i c a n d e f e n c e f o r c e ( s a d f ) w a s f i r s t s u s p e c t e d b y c i l l i e r s an d g o r ­ d o n , 4 w h o s u g g e s t e d t h a t t h e e f f i c a c y o f t he s a d f ba si c t r a i n i n g c e n t r e s m a y be l i m i te d d u e t o th e p a r t i c u l a r l y i n j u r io u s , n a t u r e o f t h e p h y s i c a l t r a i n i n g e m ­ p l o y e d . s u b s e q u e n t l y , g o r d o n 5 c r i t i c a l l y e v a l u a t e d t h e s o u t h a f r i c a n a r m y p h y s i c a l t r a i n i n g p r o g r a m m e in t e r m s o f fi t n e s s a t t a i n e d a n d i n j u r i e s s u s ­ ta in ed . r e s u l t s p u b l i s h e d f r o m this r e ­ s e ar c h r e v e a l e d u n s a t i s f a c t o r y gains in h ] van h eerden m a (biokinetics) d epartm ent o f h u m a n m ovem ent science university o f zululand private bag x i 001 k w adlangezw a 3886 e n d u r a n c e f i t n e s s , 6 an d c o n f i r m e d the a f o r e m e n t i o n e d h y p o t h e s e i s b y n o t i n g a 3 7 , 9 % i n c i d e n c e o f e x e r t i o n r e l a t e d i n j u r i e s t o r e c r u i t s d u r i n g basic t r a i n ­ i n g . 7 th e a e t io l o g y a n d p r e v e n t io n o f o v e r u s e in ju r ie s in r e v i e w o f t h e p o s s i b l e caus es o f o v e r ­ u se i n j u r i e s t o t h e l o w e r e x t r e m i t i e s , n u m e r o u s r e s e a r c h e r s 812 h a v e i d e n ­ t i fi e d c e r t a i n c o m m o n f a c t o r s t h a t s h o u l d be c o n s i d e r e d w h e n d e v i s i n g a p r e v e n t a t i v e s tr a te g y . a c c o r d i n g the r e n s t r o m a n d j o h n s o n , 13 th e s e f a c t o r s c an b e cl a s s i fi e d i n t o th e f o l l o w i n g i n ­ t r i n s i c a n d e x t r i n s i c c a t e g o r i e s : in trin s ic fa cto rs e x trin sic facto rs p o o r p h y s i c a l fi tn e s s t ra in i n g su rf a c e s p r e v i o u s i n j u r y t r a i n i n g m e t h o d s e x c e s s i v e b o d y ma ss f o o t w e a r p h y s i c a l a b n o r m a l i t i e s ---------------------------------- 17 sportsgeneeskunde vol. 6 nr. i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a n y of the above m entioned intrin sic risk factors m a y be observed in the new m ilita ry recru it. a s a resu lt, strict co m ­ p u lso ry m edical exam ination and sub­ sequ ent graded health classification of recruits p rio r to the start o f basic train ­ ing, should p la y a m ajo r role in id en ti­ fy in g and p ro tectin g those w ith an in ­ herent or acquired pred isp o sitio n to in ju ry .2 t raining surface is another varied and com plex factor affecting in ju rie s ,14 and one that is difficult to stan dardize in and around basic train in g centres. t he association of the rem aining id en t­ ified extrinsic factors ie. train in g m eth o d s8,9,14 and fo o tw e a r10,12 w ith overuse in ju ry, has received p ro m in en t focus in the lite r a tu r e .1517 t he reason for this being th eir frequen t im p licatio n and perhaps m ore im p o rtan tly, p a rtic u la rly from a m ilita ry p erspective, th eir am e­ n a b ility to m an ip u latio n for the p u r­ pose o f p rev en tin g in ju r ie s .18 a cco rd in gly, since g o rd o n s’ in itial exposition o f the p ro b lem atic high in c i­ dence of overuse in ju ries in the s a d f ,5’7 tw o m ajo r intervention strate­ gies have been considered, n am ely a re­ vision o f the south a frican a rm y p h ysical train in g p rogram m e and the m an ip u latio n o f m ilita ry footwear. w h ile the possib le corresp o n din g salu ­ ta ry effects on the p h y sic al fitness o f re­ cru its are c u rre n tly under in v esti­ g a tio n ,19 the im p lem en tatio n of these prev en tative m easures and th eir in flu ­ ence on the incidence of in ju ry, m erits fu rth er discussion. t r a in in g m e t h o d s p rio r to 1986, south a frican a rm y re­ cruits u n d erw en t a basic 10-w eek p erio d of pro gressive p h ysical con­ d itio n in g co n sistin g o f four phases o f increasin g in te n sity .20 f o llo w in g the re­ alisatio n o f the in ju rio u s nature o f this p rogram m e how ever, a revised cyclic pro gressive p h ysical train in g p ro ­ gram m e21"23 w as im plem ented, w hich stip u lated that activities such as ru n ­ n in g, ju m p in g , route-m arches and d rill-tra in in g be lim ited to the absolute m in im um d u rin g ev ery th ird w eek of train in g. t his n ew p rogram m e was la rg e ly based on the p io n eering research o f s c u lly and b esterm an 24 in the u nited states a rm y, con cern in g the successful m an ip u latio n o f basic train in g p ro ­ gram m es as p ro p h ylactic m easure against the risk o f overuse in ju ries, and stress fractures in p articular, am ong re­ cruits. f o o t w e a r r e g u l a t io n s the extrinsic aetio lo gical relationship betw een m ilita ry fo o tw ear and the risk of exertio n -related inju ries to the low er extrem ities am ong re cru its25"27 has been h ig h ligh ted . a s a resu lt, glo bal attem pts to m a n ip u late fo o tw ear have been con­ ducted in three spheres. f irstly the type o f co m b at b oot w o rn has been changed, alb eit u n su ccessfu lly.2 a ltern ativ e ap­ proaches w hich have how ever, proved to be successful in red u cin g injuries, are: • the alteratio n of w ear regu latio n of b o o ts;3 and • the p lacin g of the sho ck-ab so rbin g inn erso les insid e b o o ts.29'31 a ll three o f these approaches have been considered and experim ented w ith by the south a frican a rm y ,21'22 and c u r­ re n tly all ru n n in g activities d u rin g o r­ ganised p h ysical train in g p erio d s is c ar­ ried o ut in ru n n in g shoes w ith adequate sh o ck -ab so rb in g p ro p erties, and not in boots o r “ta k k ie s ” as w as the case in the p a st.21 f u rth erm o re, van h eerden e t a l,n and s ch w elln u s33 have re cen tly re­ p o rted the sign ificant reduction of overuse in ju ries am ong south a frican a rm y recruits b y the inco rp o ratio n of sh o ck -ab so rb in g innersoles w ith in com bat boots, thus m o tivatin g the possib le m a n d ato ry app licatio n o f this preventive m easure in the n ear future. a p p r a is a l o f p r e v e n t a t iv e m e a s u r e s in a retrospective attem pt to appraise the p o ssib le p ro p h y lac tic effect of these interventio n strategies em p lo yed b y the sa d f , the inciden ce o f exertio n -re­ lated in ju ries am ong recruits as re­ p orted b y the stu d y o f g ordon e t af carried o ut in 1982, can be com pared w ith another recent in v estigatio n 28'32 conducted five years later, after the in ­ tro d u ctio n o f the p re v io u sly discussed p reventative m easures. in these studies, a un ifo rm research p ro to co l was used con cern in g the d efinition and classifica­ tion o f in ju ry , as w ell as the m ethod of data co llectio n , thus allo w in g for a fa­ vo u rab le com parison. a s reflected in table 1, both traum atic and overuse in ­ ju rie s, interp reted as b eing sustained in the presence or absence o f a sudden p re c ip itatin g event respectively, show ed a su b stan tial reduction from 1982 as opposed to 1987, in c o n trib u t­ in g to a total recru it in ju r y incidence of 37 ,9 % (p re-in terv en tio n ) versus 17,1% (p o st-in terv en tio n ). t he incidence of o veruse in ju ries, as d istrub ted over vario us an ato m ical sites of the lo w e r ex­ trem ities (f igu re 1), has h ow ever not altered m uch. t ab le 1: r ecru it type/ year in ju ry incidence and 1982+ 1987* i n ju r y ty p e % % traum atic 7,5 1,1 o veruse 32,4 16,0 stress fractures (4,1) (0,4) t o ta l 37,9 17,1 * g o rd o n 7 *van h eerd en e t a l . 32 % in ju ry incidence expressed as a percentage o f i the to ta l n u m b er o f recruits observed in stu d y ' () d enotes a subset o f in ju ry type c o n c l u s io n it has been su gg ested 17 that the m ilita ry is an id eal m ilieu in w hich to conduct ep id em io lo gical research due to its con­ trolled n ature. a p ractical problem is, h ow ever, encountered w ith recruits w h o serve as subjects leavin g the service on com pletion of th eir period of co n s­ crip tio n . a s a resu lt, lo n g itu d in al data repo rtin g in ju ry rates from indep en ­ d ent stu d ies, as in this case, precludes 18 --------------------------------------------------------------------------------sports medicine vol. 6 no. i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) figure 1: in c id e n c e o f o v e r u s e in j u r y (% ) thigh foot heel ankle achilles lower leg knee anatomical site ■ 1982 u s 1987 an absolute com parative in terp re­ ta tio n .34 n o tw ith stan d in g this lim i­ tation, the observed data leads one to deduce that the in tro d u ctio n of the re­ vised south a frican a rm y p h ysical train in g p ro gram m e and acco m p an yin g adapted fo o tw ear regu latio n s, has b rought about a viable decrease in the risk o f exertio n -related in ju ries. a s a consequence, the efficacy of the sa d f basic train in g centres should be en­ hanced b y the dim inish ed loss of tra in ­ ing tim e and co rresp o n d in g cost of m edical care, w h ile recruits m ay derive the op tim um co n d itio n in g benefits presented d u rin g basic m ilita ry train ­ ing. r e f e r e n c e s 1. k o w a l d. n atu re and causes o f injuries in w o m en resulting fro m an endurance training p rogram m e. a m ] s p o rts m e d 1 9 8 0 ; 8 : 2 6 4 -2 6 9 . 2. bensel c k . t he effects o f tropical leather com bat boots on lo w e r ex trem ity d isorders am ong m arin e c o rp s recruits. c loth in g , e q uip m en t and m aterials e ngineering l ab ­ o ra to ry , n atick a r m y labs. technical r e­ p o rt n o . 7 6 -4 9 -c e m e l , 19 7 6. 3. sta c y r j, h u n g erfo rd r l . a m ethod to r e ­ duce w o rk -re la te d in juries d u ring basic train ing in the n e w zealand a rm y . m ilit m e d 1 9 8 4 ; 1 4 9 :3 1 8 3 2 0 . 4. c illie rs j f , g o rd o n n f. e ffect o f the sou th a fric a n a r m y ph ysical training in stru c to r cou rse on p h ysical w o r k capacity. s a j r e ­ search s p o rt, p h ysical e d ucation and r ecre­ ation 1 9 8 3 ; 6 (i) ; 3 5 -4 2 . 5. g o rd o n n f. e valuation o f the sou th a f r i ­ can a r m y p h ysical tra in in g p ro g ra m m e: f it­ ness attained and in juries sustained. u n p u b ­ lished p h d (m ed) thesis. u n iv e rsity o f the w itw a ters ra n d , 1985. 6. g o rd o n n f , van r en sb u rg j p , m oolm an j , k ru g e r pe, r ussell h m s , g ro b le r h c , c illie rs j f . the sou th a fric a n defence f orce ph ysical training p rog ram m e: part 1. e ffect o f one years m ilita ry training on en­ durance fitness. s a f r m e d ] 1 9 8 6 ; 6 9 ; 477 482. 7. g o rd o n n f , h ugo ep, c illie rs j f . the sou th a fric a n d efence f o rce ph ysical train ­ ing p ro g ram m e: p art 1 1 1 . e xertion -related in ju ries sustained at an s a d f basic training cen tre. s a f r m e d ] 1 9 8 6 ; 6 9 : 4 9 1 4 9 4 . 8. ja m es sl , bates bt, o stern ig l r . injuries to run ners. a m j sports m e d 1 9 7 8 ; 6 :4 0 5 0 . 9. m ck en zie d c , c lem en t d b , taunton je . r u n n in g shoes, o rth o tics and in jures. sports m e d 1 9 8 5 ; 2 :3 3 4 3 4 7 . 10 . n oak es t d. l o re o f r unning. c ape t ow n: o x fo rd u n iv e rsity press, 19 8 5. 1 1 . s p e rry n p n . s p o rt and m edicine. l o n d on : b u tte rw o rth s, 19 8 5 . 12. n igg b m . biom echanics, load analysis and sp o rts injuries in the lo w e r exrem ities. sports m e d 1 9 8 5 ; 2 :3 6 7 3 7 9 . the views a n d opinions exp ressed a n d the findings co n tain ed in this p a p e r a re those o f the au th o r a n d sho uld not b e con strued a s a n o f­ ficial south african d e fe n c e force position, policy o r decision, unless so des ig n ate d b y o th e r official docum entation. ‘tilc0til’ roche components: tenoxicam indications: s ym p tom atic treatm ent of the following painful inflam m ato ry and degenerative disorders of the musculoskeletal system: rheum atoid arthritis; osteoarthritis; ankylosing spondylitis; extra articular disorders, e .g . tendinitis, bursitis, periarthritis, gouty arthritis (fo r tablets). dosage: 20 mg once daily at the same time each day. the parenteral fo rm is used fo r one or two days. for treatm ent initiation in acute gouty arthritis 4 0 mg (2 tablets) once daily fo r two days followed by 20 mg once daily fo r a fu rther five days is recom m ended. contra-indications: known hypersensitivity to the drug. patients in w hom salicylates or other nonsteroidal anti­ inflam m atory drugs (n s a id s) induce sym ptom s o f asthm a, rhinitis or urticaria. patients who are suffering o r have suffered from severe diseases of the upper gastrointestinal tract, including gastritis, gastric and duodenal ulcer. before anaesthesia or surgery, ‘t il c 0 t il ’ should not be given to patients at risk of kidney failu re, or to patients with increased risk of bleeding. concurrent treatm ent with salicylates or other nsaids should be avoided. pregnancy and lactation. precautions: sim ultaneous treatm ent with anticoagulants an d /o r oral antidiabetics should be avoided unless the patient can be closely m onitored. renal function (b u n, creatinine, developm ent of oedem a, w eight gain, e tc .) should be m onitored, when giving a nsaid to the elderly o r to patients with conditions that could increase their risk of developing renal failure. packs: tablets 20 mg: 1 0 ’s, 3 0 ’s. vial pack containing 1 vial active substance and 1 am poule w ater for injection. sportsgeneeskunde vol. 6 nr. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) at the first sign of arthritic symptoms make d e f ia m 600 mg oxaprozin your choice because of its effective anti-inflammatory action deflam* 600mg improves patient’s mobility. deflam* 600mg is well accepted by patients. deflam* 600mg ensures patient compliance. d eflam * 600mg, is contra-indicated in patients in w hom acetylsalicylic acid or other nonsteroidal anti-inflam m atory medicines induce the syndrom e of asthma, rhinitis, nasal polyps urticaria, angioedema, and bronchospasm . this m edicine is not recom m ended for patients with an activ^ peptic ulcer, for use in children and patients who are hypersensitive tc oxaprozin. peptic ulceration and gastro-intestinal bleeding have been reported in patients receiving oxaprozin. use with caution in patients with intrinsic coagulation defects or sever* trauma, and in patients undergoing surgery. also use with caution in patients with com prom ised cardiac, hepatic, and/or renal function, hypertension, or other conditions predisposinc to fluid retention. elevated liver function tests m ay occur in rare instances. renal function param eters m ay be elevated, although the risk of dim inished renal function develops mosi often in patients with com prom ised renal blood flow. patients who develop visual com plaints during treatm ent should have an ophthalm ologic evaluation. ▲ »kr®med fu" prescribin9 in,° rm at' ° n available on request from: -registered trademark a k r o m e d pro ducts (pty) limited, po box 42, electron ave, isando, 1600. tel: (011) 974-8631 reg. no. r/3 . 1/ 1zs co. reg. 05/13586/07 def. d/f 5690/912/bsr. times enlarged r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) n u t r i t i o n fat in the diet m ieke f a b er in g e n e r a l, fats m a y be d e f i n e d as a g r o u p o f o r g a n i c s u b s t a n c e s w h i c h are g r e a s y t o t o u c h , i n s o l u b l e in w a t e r and are s o l u b l e in a l c o h o l o r ether. c h e m i ­ c a l l y s p e a k i n g fats a re o r g a n i c c o m ­ p o u n d s o f c a r b o n , h y d r o g e n a n d o x y ­ gen. t h e fats in f o o d ar e c a ll e d t r i g l y c e ­ ri de s ( n e u t r a l fats ). t r i g l y c e r i d e s a re e s ­ ters o f g l y c e r o l ( t h e w a t e r s o l u b l e c o m ­ p o n e n t ) a n d f a t t y a cid s w h i c h a re th e basic c o m p o n e n t s o f t r i g l y c e r i d e s . m o s t f a t t y acids in f o o d s are s tr a i g h t, e v e n n u m b e r e d c a r b o n c h a in s , c o n t a i n i n g as f e w as 4 o r as m a n y as 2 4 c a r b o n a t o m s . s h o r t c h a in f a t t y acids c o n t a i n 4 t o 6 c a r b o n a t o m s , m e d i u m ch a i n f a t t y a ci ds c o n t a i n 8 t o 1 2 c a r b o n a t o m s , a n d l o n g c h a i n f a t t y acids m o r e th a n 1 2 c a r b o n a t o m s . f a t t y acids can be d i v i d e d i n t o s a t u r a t e d f a t t y acids, m o n o u n s a t u r a t e d f a t t y a cid s a n d p o l y ­ u n s a t u r a t e d f a t t y ac ids. t h e s tat e o f s a t u r a t i o n r e s u l t s f r o m t h e r a t i o n o f h y ­ d r o g e n a t o m s t o c a r b o n a t o m s in t h e basic c a r b o n c h a i n w h i c h f o r m s th e i n ­ d i v i d u a l f a t t y acid . a f a t t y acid in w h i c h all o f t h e c a r b o n a t o m s in th e ch a in h a v e t w o h y d r o g e n a t o m s a t ­ t a c h e d t o it is s a t u r a t e d . in u n s a t u r a t e d f a t t y a ci ds a d o u b l e b o n d is f o r m e d b e ­ t w e e n t h e t w o a d j o i n i n g c a r b o n a t o m s o f w h i c h h y d r o g e n a t o m s a re m is si n g. m o n o u n s a t u r a t e d f a t t y a cid s h a v e o n l y o n e s u c h d o u b l e b o n d a l o n g t h e c a r b o n cha in. if t w o o r m o r e d o u b l e b o n d s o c ­ c u r a l o n g t h e c a r b o n c h a i n o f t h e f a t t y m ieke faber research institute fo r n ational diseases medical research council acid, it is c a ll e d a p o l y u n s a t u r a t e d f a t t y acid. a f a t t y ac id t h a t c a n n o t be m a n u f a c ­ t u r e d b y t h e b o d y an d m u s t t h e r e f o r e be o b t a i n e d f r o m th e d i e t is k n o w n as an e s s e n ti a l f a t t y acid ( e f a ) . l i n o l e i c ac id is t h e m a j o r e f a in t h e die t. t w o t o 3 % o f t h e e n e r g y i n t a k e s h o u l d be p r o v i d e d b y e f a , ie. a b o u t 2 t o 5 g r a m p e r d a y o f l i n o l e i c acid f o r an a d u l t. t w o to th ree p e r c e n t o f the e n e r g y intake s h o u l d be p r o v i d e d by e s sen tia l f a tt y a cid s t h e d e g r e e o f u n s a t u r a t i o n in a n y fat p l a y s an i m p o r t a n t r o l e in d e t e r m i n i n g its p h y s i c a l n a t u r e . fat s c o n s i s t i n g o f p r e d o m i n a n t l y s a t u r a t e d f a t t y acids c o n t a i n i n g m o r e t h a n 1 4 c a r b o n a t o m s a re s o l i d at r o o m t e m p e r a t u r e , w h i l e t h o s e w i t h a h ig h p r o p o r t i o n o f u n s a t u ­ r a t e d f a t t y a cid s as w e l l as t h o s e c o n ­ t a i n i n g 1 2 c a r b o n a t o m s o r less are u s u a l l y l i q u i d at r o o m t e m p e r a t u r e a n d d o n o t s o l i d i f y e v e n at l o w t e m p e r a ­ t u r e s . v e g e t a b l e an d m a r i n e o i l ca n be h a r d e n e d a n d t u r n e d i n t o s o l i d fa ts b y h y d r o g e n a t i o n , a p r o c e s s in w h i c h u n ­ s a t u r a t e d f a t t y ac ids a r e c o n v e r t e d to s a t u r a t e d f a t t y acids b y t h e i n t r o d u c ­ t i o n o f h y d r o g e n i n t o t h e a v a i la b l e d o u b l e b o n d s o f u n s a t u r a t e d f a t t y ac id s. t h is e n a b l e s t h e m a n u f a c t u r i n g o f m a r g a r i n e . in t h e m a n u f a c t u r i n g o f v e g e t a b l e s h o r t e n i n g s a n d m a r g a r i n e s , s o m e , b u t n o t all, o f t h e d o u b l e b o n d s are h y d r o g e n a t e d . w h e t h e r f a t t y ac id is s a t u r a t e d o r u n s a t u r a t e d d e t e r m i n e s t h e e f f e c t o f th e fa t o n p l a s m a li p i d l e ve l s. w h i l e s a t u ­ ra t e d fa t ra ise s p l a s m a c h o l e s t e r o l , p o l y u n s a t u r a t e d fa t t e n d s to l o w e r it. a n y f a t t y acid w h i c h c o n t a i n s a d o u b l e b o n d ca n ex i s t in e i t h e r o f t w o g e o m e t r i c a l l y i s o m e r i c f o r m s . t h e y can be e i t h e r in t h e cis f o r m o r in th e tr a n s f o r m . in t h e cis f o r m t h e m o l e c u l e fo l d s b a c k u p o n i t s e l f at ea ch d o u b l e b o n d . in t h e tr a n s f o r m th e m o l e c u l e e x te n d s t o its m a x i m u m l e n g t h . t h e n a t u r a l u n ­ s a t u r a t e d f a t t y acids in f o o d e x i s t in th e cis f o r m . d u r i n g t h e h y d r o g e n a t i o n s o m e o f t h e f a t t y a cid s a re c h a n g e d f r o m t h e cis t o t h e t r a n s f o r m s , b u t b o t h f o r m s a re u t i l i z e d b y th e b o d y . trans i s o m e r s o f p o l y u n s a t u r a t e d acids d o n o t h a v e e s s e n t ia l f a t t y ac id a c t i v i t y an d l a c k t h e a b i l i t y p o s s e s s e d b y cis i s o m e r s o f l o w e r i n g t h e l e v e l o f l i p o p r o t e i n s in p l a s m a . fats ar e m i x t u r e s o f d i f f e r e n t t r i g l y ­ c e r i d e s . fat s in f o o d c o n t a i n m i x t u r e s o f s h o r t a n d l o n g c h a i n f a t t y acids a n d o f s a t u r a t e d a n d u n s a t u r a t e d f a t t y acids. n o n a t u r a l fa t is m a d e u p c o m p l e t e l y o f e i t h e r s a t u r a t e d o r u n s a t u r a t e d f a t t y ac ids. a n i m a l fats c o n t a i n m a i n l y s a t u ­ r a t e d f a t t y ac ids. m o s t p l a n t fats c o n ­ ta in p r e d o m i n a n t l y p o l y u n s a t u r a t e d f a t t y ac ids. c o c o n u t o il is an e x c e p t i o n in t h a t it is a p l a n t fat m o s t l y m a d e u p o f s h o r t c h a i n s a t u r a t e d f a t t y acids. a n o t h e r e x c e p t i o n is o l i v e oil w h i c h is ri c h in m o n o u n s a t u r a t e d f a t t y acids. fats s u c h as bu tte r, m a r g a r i n e , la rd a n d o i l s a re k n o w n as v i s i b l e fats. t h is is, h o w e v e r , n o t t h e o n l y s o u r c e o f fat in t h e d i et . t h e f a t p r e s e n t in f o o d s s u c h as in m e a t , w h o l e m i l k , egg y o l k , a v o ­ c a d o a n d n u t s a re k n o w n as i n v i s i b l e fat o r s o m e t i m e s a ls o c a lle d h i d d e n fat. t h e p r i m a r y f u n c t i o n o f fa t in th e h u m a n d i e t is t o s u p p l y th e b o d y ’s m o s t c o n c e n t r a t e d s o u r c e o f e n e r g y . o n e sportsgeneeskunde vol. 6 nr. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ^uraotnoim gram o f fat su p p lied 9 kcal. (p rotein and carb o h yd rates p ro vid e 4kcal/gram ). b ecause of the high en erg y d en sity of fat, high fat diets are alm o st alw a y s also high in en ergy so, except in the p h y si­ c a lly active, lead to obesity. fat also p la y s a role in the sa tie ty value of food. m eals that are m oderate in fat content also have a g reater satie ty value than those that are lo w in fat. a n o th er func­ tion o f fat in the diet is as a carrier of fat-so lu b le vitam in s n am ely vitam ins a , d , e a n d k . t he am ount of fat in the diet varies greatly. in m ost pro sp ero us countries fat u s u a lly co n trib u tes 35 to 45% of the to tal energy. in som e p o o r countries the figu re is 15% o r even lower. it is dif­ fic u lt to state a m in im um requirem en t i t is also recom m en d ed that the intake o f sa tu ra ted f a t sh o u ld be d ecrea se to less than 10% o f the en erg y intake. for fat in tak e. because there is a co rre­ lation betw een fat in tak e and p lasm a ch o lestero l levels and since elevated p lasm a ch o lestero l levels are associated w ith an increased risk o f co ro n ary ar­ te ry disease it is recom m ended that fat sh o uld not exceed 30% of the to tal d a­ ily en ergy in tak e. w hen fat intake is v e ry lo w (10% of to tal e n erg y) the v o l­ u m e of food that should be taken to m eet en erg y needs m ight becom e a p ro b lem , eg. in ch ild ren w h o are active and therefore have a high en ergy need, b ut w ith a sm all cap acity for food. it is also recom m ended that the intake of satu rated fat sh o uld be decreased to less than 10% of the en erg y intake. the use o f p o ly u n satu rate d fat should be in ­ creased to 10% of en ergy intake. this co uld be achieved b y su b stitu tin g the use of anim al pro d ucts w ith p lan t fats. the am ount of fat in loog edible food as w ell as the am ount of fat per p o rtio n of different types of food is listed in the table below . g ram s o f fat per loogm edible food as well as grams fat per po rtio n size food fat per loog p ortion size fat per portion food fat per loog p ortion size fat per portion sugar 0 1 teaspoon 0 cake 1 5 , 7 50g 7,85 vegetable 0-1 1/2 cup 0-1 doughnuts 15, 8 one 7,9 fruit 0-1 one 0-1 ice cream 16 ,0 1 scoop 6,4 rice 0,1 1/2 cup 0, 06 french fries 1 6 , 6 loog 1 6, 6 skim milk 0,2 250ml 0,5 cheese spread 2 1 , 2 log 2 , 1 2 breakfast cereal 0 , 3 3 , 4 1/2 cup 0 , 1 0 , 7 feta cheese 2 1 , 3 30g 6, 3 9 pasta 0, 4 1/2 cup 0,3 samosa 2 5 , 7 one small 10 ,7 9 dried beans, cooked 0,5 1/2 cup 0,5 fatt y p o rk 2 7 , 2 90g 2 4, 48 wh ite fish, eg. stock fish 0,8 90g 0,72 p o lo n y 2 8, 3 1 thin slice 4,53 haddock 0, 9 90g 0,8 1 fa tty mut to n 29 , 0 90g 26, 1 sole 0, 9 90g 0,81 fa tty beef 29 ,1 90g 2 6 , 1 9 2 % milk 1.9 250 ml 4,75 frank furte r 29 ,2 one 17,5 2 mussels 2 , 0 60g 1,2 chocolate 30,3 50g 1 5 , 1 5 oysters 2,2 60 g 1,3 2 niknaks 3 1 , 3 40g 12,52 white bread 2, 5 1 slice 0, 75 cheddar cheese 33,1 30g 9,93 w h o le milk 3,3 250m l 8,25 cream cheese 34 , 9 1 tablespoon 13,9 6 w h ol ew he a t bread 3,4 1 slice 1,02 wh ippin g cream 37 ,0 1 ta bl esp oon 1 1 , 1 medium fat fish, eg. snoek 3,7 90g 3,33 po tat o chips 40,3 10 nuts 9, 28 l o w fat cottage cheese 4,5 60g 2 , 7 peanuts 49 ,2 30g 14,7 6 trou t 4,5 90g 4,05 bacon 49,2 1 rasher 4,92 lean beef 6,1 90g 5, 49 sun fl o we r seeds 4 9 , 6 1 tablespoon 7,44 chicken, w h i th o u t skin 6 , 7 90g 6,03 peanut butter 5 1 , 1 log 5 , 1 1 eggs 11 , 2 one 5,6 mayonnaise 53,5 1 tablespoon 12,31 lean m utt on 12,3 ' 90g 1 1 , 0 7 walnuts 6 1 , 9 10 halves 1 8 , 5 7 chicken, w it h skin 12 ,6 90g 11 ,3 4 ha zel nut s 6 2 , 6 10 nuts 6, 26 fatty fish, eg. butterfish 13 ,0 90g 1 1 , 7 0 coco nut 64 , 5 1 tablespoon 7,74 lean p o rk 15, 3 90 g 1 3 , 7 7 brazil nuts 66 , 2 10 nuts 19 ,8 6 avocado 15,3 30g 4, 5 9 margarine 8 1 , 0 1 teaspoon 4, 05 cheese sauce 15 ,4 1 tablespoon 3,85 butter 8 1 , 0 1 teaspoon 4,05 pancake 15, 5 one 10,85 oil 100 5,0 22 --------------------------------------------------------------------------------sports medicine vol. 6 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) harvard expert on sports injuries in children for sports medicine congress at sun city big injuries to small athletes are frequently seen in clinical practice and are o f great concern to both the medical and sporting com munities. l y le j m icheli, clinical professor o f orthopaedic surgery at harvard medical school and consultant to the boston children's hospital and the boston back centre w ill be participating in this year's sports m edicine congress to b e held at sun city from 24-27 april 1991. particularly w ell known for his contributions to the treatment o f spinal injuries, including the hip and pelvis, p rof m icheli has developed a special interest in strength for children to prevent sports related injuries. other overseas guests at the congress which focuses on prevention and rehabilitation o f sports injuries include w ell known physiologist, barbara drinkwater, cardiac exercise specialist p rof ralph paffenbarger and cardiac rehabilitation practitioner, d r neil gordon. prof drinkwater's research has concentrated on the female athlete, particularly with regard to the problem o f osteoporosis and maximizing bone mass in the premenopausal years. the them es o ft h e congress include rehabilitation o f sports injuries, sport sp ecific rehabilitation o f specific rehabilitation and the role o f exercise in the rehabilitation o f various medical and psychological disorders. these include psychiatric disorders, organ transplantation, obesity, arthritis, hypokinetic disorders, physical disability and cardiovascular aspects. registration forms are available from the congress secretariat, sports m edicine a ssociation c ongress, po box 13206, c lubview , 0 0 1 4 or phone riekie labuschagne at (012) 6 6 3 -3290. sports medicine congress 24-27 april 1991 nb: please do not send any money now preliminary registration form i wish to: a) attend the congress yes/no b) present a paper on one o f the following topics: 1).......... 2) ........... yes/no c) present a poster on one o f the following topics: yes/no 1)....................................................................................... 2) ....................................................................................................... d) attend a workshop on one o f the following topics: (specify) yes/no 1). 2). 3). 4). 5). e) present a workshop/s on the follow ing nam e: .................................................................. initials: ......................................... title: postal address: ...................................... code: tel (w ): ......................................... (h): signature: .............................................. date: .............................................. please forward this registration form to the fo llo w ­ ing address: congress secretariat sports medicine association po box 13 2 0 6 clubview 00 14 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) )©mtdhi mirncaim sp©et§ medncnnn© association!! >md=afrikaans© spojrtgemeestoime-veireifiiigiifiig a s p e c ia lis i g r o u p o f ih e m a s a ( i n c o r p o r a te d a s s o c ia tio n not fo r gain ) ’n s p e s ia le g r o e p v an d ie m v s a (in g e ly f d e v e r e n ig in g s o n d e r w in s b e ja g ) dear doctor, po box 13206 clubview 0014 february 1990 the characteristic that distinguishes a professional from an educated person is the professional person's desire and responsibility to stay abreast of the developments of his or her field of expertise. the halflife of our professional knowledge is about 3 years, and for this reason it is vitally.important to continuously refresh and supplement our knowledge. sports medicine, the official mouthpiece of the sa sports medicine association, has over the years become a treasured source of knowledge for the health care professional in the sports medicine arena. the journal features not only original research papers and articles by leading specialists in sports medicine, but also current news and relevant abstracts. the publishing of sports medicine has been taken overby medpharm publications. the journal will be published quarterly namely, february, may, august and november. due to the present rate of inflation sasma are no longer able to distribute sports medicine free of charge and have reluctantly introduced a subscription fee of r20,00 per annum (members of sasma will continue to receive the publication free of charge). in addition to managing costs, this will enable the editorial board maintain a high quality editorial content and render a more effective service to you, the health care professional. your subscription to sports medicine is an investment in your future and the future of the health care profession. we count on your continued support. regards, clive noble editor sports medicine x ----------------------------------------------------------------------------------------------------------------------------------------------------------name: .............................................................................................................................................. address: .......................................................................................................................................... code: ................................................................. tel: ................................................................. enclosed please find my cheque/postal order payable to sasmafor: o r30for full membership* to sasma (this includes receiving sports medicine free of charge) o r25 for associate membership** to sasma (this includes receiving sports medicine free of charge) o r25 for student membership*** to sasma (this includes receiving sports medicine free of charge o r20 + gst (r22,60) for subscription to sports medicine mote * full membership: medical practitioner who is a member of masa ** associate membership: members of supplementary health service professions, registered with the samdc and who are members of their own professional associations *** student membership: medical students who are in their clinical years r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports medicine sportgeneeskunde jo u r n a l of t h e s.a. spo rts m e d ic in e associatio n ty d sk r if v a n die s.a. sportgeneeskunde-vereniging issn 1015/5163 vol 5/no 1 february 1990 price r5.00 + gst the influence o f a shock-absorbing innersole on the incidence o f exertion-related injuries energy value o f food d ie waarde van pre-seisoensevaluering en post traumatiese fisieke rehabilitasie r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) beat the pain.go the distance. c i b a — g e i g y ddophenac diethylammonium 1,16 g/100 g f e g . n o . u / 3 . 1 / 7 7 w i l s e n a c h * 8 8 i > new \bltaien emulgel.the unique gel cream combination to beat pain and inflammation. • e m u l g e l k e e p s you in actio n . it is th e ideal a n t i i n f l a m m a t o r y t r e a t m e n t fo r the relief o f localised i n f la m m a ti o n a n d pain in s p o r ts inju ri es d u e to s p ra i n s , str ai n s a n d bruises. • ' e m u l g e l ’s u n iq u e c o m b i n a t i o n o f c r e a m a n d gel allow s for the p e n e t r a t i v e effect o f r u b b i n g in, whil e the gel fo rm s a lay er to al p e rs i st e n t p e n e t r a t i o n . • e m u l g e l ’s d e e p p e n e t r a t i n g ac tio n c o n fi n e s itself to t h e local p r o b l e m , giving relief, wi th m i n i m u m lik eliho o d o f sidecffect s. • ' e m u l g e l p ro v id e s o n t h e s p o t , c o n v e n i e n t m e d i c a t i o n . • f r o m c ib a-g eig y . l e a d e r s in t r a n s d e r m a l th e ra p y . s o o t h i n g e m u l s i o n creati f o r t h e p e n e t r a t i v e effec o f r u b b i n g in c o o l i n g g e l f o r m s a la y e r l o r g r a d u a l p e n e t r a t k votiaren n o w a v a i l a b l e a l y o u r p h a r m a c y w i t h o u t p r e s c r i p t i o n . emulgel r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports medicine sportgeneeskunde j o u r n a l o f t h e s.a. s p o r t s m e d i c i n e a s s o c ia t io n t y d s k r i f van d ie s.a. s p o r t g e n e e s k u n d e -v e r e n ig in g v o l u m e s n u m b e r 1 f e b r u a r y 1989 e d ito r in c h ief: d r c n o ble m b b c h , f c s ( s a ) a ss o c ia te e d ito rs: p r o ft n o a k e s , m b c h b , m d d r d a w ic v a n vclden m b c h b (s tell) m p ra x m e d (pretoria) a dvisory b oard : m e d i c i n e : d r i cohen m b c h b , d .o b si. r c o g o r t h o p a e d i c t r a u m a t o l o g y : d r p f irer b s c (eng) , m b b c h ( w i t s ) ,m m e d (ortho) (w a s) b n g e h u g o m b c h b ,m m c d ( c h ir ) o r t h o p a e d i c s : d r j c usdin m b b c h , f r c s (e d in ) c a r d i o l o g y : c o l d p m y burgh s m m b c h b f a c c p h y s i c a l e d u c a t i o n : p r o f h an nes b o th a d p h il (p h y s e d) g y n a e c o l o g y : d r j a c k a d n o m b b c h (w its ), m d (m e d ), d i p o & g ( w hs) contents editorial comment ............. 3 preventative sports m edicine t he influence of a shock-absorbing innersole on the incidence o f exertion-related inj uries ..................... ............. 4 nutrition 10 sportbeserings d ie waarde van pre-seisoensevaluering en 12 sports physiology an evaluation o f hamstring/quadricep strength ratios in elite long distance runners and 16 pictures courtesy o f photofile/1 mage b a n kp u b l i s h e d b y t h e s o u t h a f r i c a n s p o r t s m e d i c i n e a s s o c i a t i o n h a t f i e l d f o r u m w e s t 1067 a r c a d ia s t r e e t h a t f i e l d p r e t o r i a . 0 0 8 3 t h e j o u rn a l o f t h e sa s p o n s m e d i c in e a s s o c ia tio n is p u b li s h e d b y m e d p h a r m p u b l ic a ii o n s , 3 rd f lo o r n o o d h u l p l ig a c e n t r e , 2 04 b h f v e rw o e rd d r i v e , r a n d b u r g 2 1 9 4 . t el: (0 1 1 ) 7 8 7 -4 9 8 1 /9 . t h e v ie w s e x p r e s s e d in t h is p u b li c a t io n a r e t h o s e o f t h e a u t h o r s a n d n o t n e c e s s a r i ly th o s e o f t h e p u b li s h e rs . p r in te d b y t h c n a ia l w itn e s s p r im in g and p u b lis h in g c o m p a n y ( p t ' ) l td s p o r t g e n e e s k u n d e vol s. n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) van bencard s3 relifen 500 mg per tablet reg nr r/3.1/265 oorrelifen 500 i die anti-inflammatoriese middel ^ wat beweeglikheid verbeter bemarkdeur bencard afdeling van rbeege nc h ^ 0 3 9 h6 8 ^ a c e u tic a ls (e d m s > b p k posbus 347. bergvlei 2012 rellfen 500 en die bencard logo is handelsmerke jndikasies.rumatoiede a rtritis en osteoartntis/artrose. newe-effekte en spesiafe voorsorgmaatreelss a t m e s 9e'yktydl9e t0ed'emn9 van sulf“ m en h,dantoiene pept,ese u,kusn ^ ede verdere inligting is van die mediese departement verkrygbaar. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) e d it o r ia l sports medicine in south africa t h e sp o rts m e d i c i n e a sso ci at ion o f s o u th africa ( s . a . s . m . a . ) is only six yea rs old . t h o s e o f us w h o w ere involved in its f o u n d a t i o n k n o w that it to o k as m a n y years before s . a . s . m . a . ’s fo u n d a ti o n to finally start an association. n o w al m o st six years later o n e m u s t look at w h at we h av e ac h iev ed a n d a t t e m p t to assess o u r fu ture. w h e n we first b eg an w e s ta rte d as a g r o u p o f d o cto rs u n d e r th e au sp ic e s o f t h e s o u t h a fr ica n m ed ic a l a sso ci­ ation. t h i s m e a n s th a t o n ly m e m b e r s o f the m e dical p r o ­ fession ar e allowe d to vo te b u t affiliate m e m b e r s ca n be co -o p te d o n to the as s ociation. t h e s e affiliate m e m b e r s m u s t be p eo p le o f s t a n d i n g in s p o r ts s ci en ce , e.g . s p orts p h y s i o th e r a p is t s . as on ly a small n u m b e r o f d o c to rs have a special intere st in s p o r t s m e d i c i n e this m e a n s th a t o u r association will always r e m a i n s m a l l . t h e r e are h o w e v e r a n u m b e r o f ways that we can ch an g e this sit u at io n . f irs tly w e can e d u c a t e m o r e d o c to rs so that a g re a t e r g en era l in te re st in s p o r ts m e d i c i n e can be s t i m u ­ lated. t h i s can be d o n e in a n u m b e r o f ways. t h i s jou rn al is a m a jo r asset in this re g a r d . by p u b l i s h i n g in te re stin g articles m o r e a n d m o r e d o c to rs m a y b e c o m e intere st ed a n d join o u r asso cia tio n. l e c t u r i n g a n d co n g re sse s by s p orts m e d i c i n e sp ec ia lis ts m a y also h e lp in this re g ar d . u n f o r t u n a t e l y c a p e t o w n u n iv e r s i t y hav e th e only fa­ cility u n d e r g u i d a n c e o f p r o f ess o r t i m n o a k e s th a t has a d ir e c t i n v o l v e m e n t with s p o r t s scien ce. o t h e r u niversities re q u i r e s im i la r e s t a b li s h m e n t s . at g ra s s ro o ts level s p o r ts m e d ic in e s h o u l d be t a u g h t to u n d e r g r a d u a t e s tu d e n t s . at p re s e n t i k n o w o f no s u ch te a c h in g . w i t h le isure tim e in ­ cre asing m o r e a n d m o r e p eo p le ar e ta k in g p a rt in spor t a n d th e re fo re s p o r ts m e d i c i n e will b e c o m e pro g re ssi v el y m o re i m p o r t a n t . f in ally o n e m u s t c o n s id e r a s p o r ts m e d i c i n e association that will i n c lu d e all i n t e re st e d p a rt ie s a n d n o t just d o c ­ tors. in th e u . s . a the a m e r ic a n college o f sp o rt s m e d ic i n e fulfills this role. h e r e c o a c h e s , t r a i n e r s , p h y s i o ­ t h e ra p is t s , d ie ti c ia n s , d o c t o r s , etc. all m a y b elo n g to this asso ci at ion. po ssibly ev en two ass ociatio ns m a y be feas­ ible. it is i m p e ra t i v e th a t in this nex t d e c a d e l ead ing u p to the yea r 2000 s p o r ts m e d i c i n e a n d its associatio n s h o u l d go fro m s t r e n g t h to s tr e n g t h . dr. clive n o b l e m b b c h , f c s ( s a ) e d it o r i n c h i e f l * * . *m c o h s p o r t g e n e e s k u n d e vol 5. n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) preventative sports medicine the influence of a shock-absorbing innersole on the incidence of exertion-related injuries sustained by military recruits hj van heerden, pe kruger, nf gordon, jf cilliers, ad hales, ar oberholzer abstract k eyw o rd s: shock-absorbing innersole, exertion-related injuries, m ilitary recruits t he aim o f this study was to determine the influence o f a shock-absorbing innersole on the incidence o f exertion-related injuries, of the lower extremities, among recruits during basic training in the south african army. injuries were classified according to the presence (group 1) or absence (group 2) o f an obvious precipitating event, which allowed for the respective interpretation o f a traumatic or overuse injury. group 1 injury incidence (g l) was lower than the group 2-injury incidence (g2) for both the standard boot (st ) and the shock-absorbing boot (so) (st-g1 = l,l% v s g 2 = 16,0%;so-g1 = 1,0%v s g2 = 9,8%), indicating a predominance o f overuse injuries. t he variation in gl-injury incidence per boot type was negligible and insignificant ( p > 0 ,l) . t he difference between the stg2 and sog2 injury incidence was significant (p=s0,05), as was the case for total recruit injury incidence (s t = 17,l% v ss o = 10,8%) but to a lesser degree (p < 0,1). t he so thus provided significantly better protection against the risk o f exertion-related injuries. t his was especially the case in respect o f overuse injuries o f the lower extremities during basic training. t his observation was attributable to the effective functioning of the shock-absorbing innersole within the boot. h j van h eerden, m a b iokinetics, 1 m ilita r y h ospital b io kin etics centre p e kruger, p h . d u niversity o f pretoria n f g ordon, m b b c h , p h . d . , 1 m ilita ry h o spital b io kin etic s centre j f cilliers, p h . d . , 1 m ilita r y h o spital b iokinetics centre a d h a les, b a (h ons) p h y s e d , 1 m ilita r y h o sp ita l b io kin etics centre a r oberholzer, n a t d ip chir, p odiatry d epartm ent, 1 m ilita r y h o sp ita l a uthors address: h j van h eerden d epartm ent o f h u m a n m o ve m e n t science, u niversity o f z u lu la n d p riva te b a g x i 0 0 1 , k w a d l a n g e z wa 3886 t h e s t r e n u o u s d e m a n d s pla ced on the m u s cu l o s k e l e t a l s t r u c t u r e o f m ilita ry r e ­ c ru its u n d e r g o i n g t h e i r initial p e r i o d of int en sive t r a i n i n g a n d p h ys ic al c o n ­ d it i o n i n g (bas ic tra i n i n g ) ca n at tim es be excessive. t h i s o b s e r v a ti o n is reflected b y t h e hig h in c id e n c e o f inju ry, p r i m a r ­ ily to the low er e x t r e m i t ie s , th a t have b e e n r e p o r t e d for b o th fore ig n f o r c e s , 1'3 a n d the s o u t h a fr ican a r m y . 4 b e n s e l 1 a n d k o w a l 2 n o te d a 3 7 % a n d 2 6 % in j u r y rate for a m e r ic a n m a r i n e s a n d a r m y r e ­ cru i ts respectively, w h il e stacy a n d h u n g e r f o r d 3 r e c o r d e d an a l a rm in g 6 5 ,4 % i n c id e n c e o f “w o r k r e l a t e d ” i n j u ­ ries a m o n g n e w z e a l a n d a r m y re cr u its . in the s o u t h a frican a rm y , g o r d o n et al4 d o c u m e n t e d a 3 7 , 9 % in c id e n c e o f ex e rt i o n -r e la te d in j u ri e s s u s t a i n e d by r ecr u its d u r i n g basic tra i n i n g . t h e tra n s it i o n fro m civilian fo otw ear to m ilita ry fo o tw e ar has b e e n im p lic a te d by v a ri o u s r e s e a r c h e rs as an i m p o r t a n t factor in c o n t r i b u t i n g to th e in c id e n c e o f e x e r t i o n r e la te d in j u r i e s , o f th e low er e x t r e m i t ie s , a m o n g r e c r u i t s . 5'7 t h e fact tha t civilian fo o tw e ar c o n s t r u c t e d fro m m a te ria ls th a t ar e lig h t e r a n d hav e b e t te r s h o c k a b s o r p t i o n q u ali tie s t h a n m ilita ry footwear, m a y h av e an influ en ce o n the a m o u n t o f str es s i n c u r r e d by i n d i v id u a l s e n g a g e d in t r a i n i n g . 8 as a r e s u lt t h e re has b e e n g r o w i n g s u p p o r t for the use of ath le tic fo o tw e ar s u c h as r u n n i n g sh oe s, for ph ysical c o n d it i o n i n g by m a n y mili­ tary u n i t s . 7'9,l0'n w h il s t this a p p r o a c h has b e e n a c c e p te d a n d i n t r o d u c e d in the s o u th a fr ic an a r m y , 12 s o m e foreig n c o m m a n d e r s h a v e c o u n t e r e d this a d v o ­ cacy, by r e a s o n i n g t h a t since the so ld ier fights in the b o o t , he s h o u l d t ra i n in the b o o t . " as a f u r t h e r p r o p h y l a x i s , at ten 4 ---------------------------------------------------------s p o r t s m e d i c i n e vol 5. no i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) preventative sports medicine tion h as b e e n focu sed on th e m o d i fi ­ cation o f th e m ilita ry b o o t as a n o t h e r me an s o f d e c re a s i n g t h e in c id e n c e o f in ju r v a m o n g r e c r u i t s . , i !s1013 in o r d e r to inv es tiga te t h e effect of such a p r e v e n t iv e m e a s u r e , a s t u d y was c o n d u c te d to d e t e r m i n e the influ en ce of two d iffe re n t b o ot t y p e s , on th e inc i­ d en ce o f e x e rt i o n -r e la te d i n ju ries o f the lower ex t re m i t ie s a m o n g r e c r u i t s d u r i n g basic t r a i n i n g in the s o u t h a fr ic an army. subjects a n d m eth o ds in this s t u d y n a t io n a l s e r v ic e m e n th a t p re s e n t e d th e m s e l v e s for t h e f e b r u a r y 1987 in ta k e at a s o u th a fr ican a r m y b a ­ sic t r a i n i n g c e n t r e s erv ed as s u b j e c t s . all s ubjec ts u n d e r w e n t a c o m p r e h e n s i v e medica l e x a m in a t i o n b efo re c o m m e n c ­ ing w i th basic t r a i n i n g a n d on ly tho se tha t w e re classified as m e d i c a l l y fit, w e re c o n s id e re d for th e study. ini tially a total of 750 s u b j e c t s fo rm e d th e s a m p l e , b u t p ri m a ri l y as a re su lt o f t ra n s fe rs to o t h e r u n it s , 280 s u b jects w e re w i t h d r a w n w ith in the d u r a t i o n o f t h e study. t h e s u b j e c t ’s av er ag e age w as 19,8 years. b e­ fore t h e start o f th e p ro je c t all su bjects were i n f o r m e d a b o u t t h e p u r p o s e o f the stu d y a n d th e p r o c e d u r e t h a t was to be followed. t h e s u b jects w e re iss u ed r a n d o m l y wi th o n e o f t h e tw o typ es o f b o o t s , until an e x p e r i m e n t a l g r o u p o f 250 a n d one co n tr ol g r o u p o f 500 s u b j e c t s was fo rm e d . d u r i n g t h e iss u ein g p r o c e d u r e recr u its h a d t h e ir feet m e a s u r e d by m e m b e r s o f t h e s o u th a fr ican b u re a u o f s t a n d a r d s on a m e a s u r i n g devic e d e ­ sign ed specifically for th e m i l i ta ry last a cc o rd in g to t h e m o n d o p o i n t sy st em . a n y f u r t h e r p r o b l e m s w e re re s o lve d by the p e rs o n a l a t t e n ti o n o f a p o d i a t ris t . figure 1: t h e s t a n d a r d l eath er bo ot typ e figure 2: t h e s h o c k a b s o r b i n g in n er so le description of the d iffe r e n t boot types (a s docum ented by the s o u th a frica n b ureau o f s ta n d a r d s ).14 standard boot type t h e c u r r e n t s t a n d a r d issue le a t h e r bo ot o f t he s o u t h africa n a rm y, is k n o w n as the “v as b yt” b o ot. t h i s b o o t is refe rred to as t h e s t a n d a r d bo ot (s t ) in this s t u d y a n d was w o r n b y t h e c o n tr ol g r o u p ( f ig u r e 1). sorbothane boot type t h e e x p e r i m e n t a l bo ot t h e n is r e fe rre d to as t h e s o r b o t h a n e bo ot (s o) in this study. t h i s bo ot was identical to the s t a n d a r d b o o t , e x cep t for th e i n c lu s io n o f a s h o c k a b s o r b i n g in n er so le. t h e i n ­ nerso le was sp eci ally d e s ig n e d a n d p r o ­ d u c e d fr o m a m a te ria l k n o w n as s o r b o ­ tha ne . s o r b o t h a n e is the t ra d e n a m e for a ty p e o f visco-elast ic p o l y m e r wi th specific p r o p e r t i e s well k n o w n for its u n i q u e c u s h i o n i n g a n d s h o c k a b s o rb ing c a p a b i li t i e s . 16'20 a n e x a m in a t i o n ol the i nn erso le reveals a b u i l d u p in the two m a in a rch es o f t h e f o o t : s p o r t g e n e e s k u n d e vol 5. n r i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) preventative sports medicine • the m edial l o n g i tu d i n a l a r c h ( m l ); a n d • the t ra n s v e rs e m e ta ta rs a l a r c h (t m ) . t h e in n e r s o l e p r o c e e d s fr o m the heel o f t h e foot to just p o s t e ri o r o f t h e m e ta ta rs al h e a d s ( f i g u r e 2). the basic t r a in in g programme wee ks a n d wa s o f a cy clic-p ro gress iv e n a t u r e . 12 all ex erci ses w e re p e r f o r m e d str ictly a c c o r d i n g to p r e s c r i p t i o n . 21 d u r i n g all o rg a n is e d p h ys ic al train in g p e ri o d s r u n n i n g s h oe s are w o r n a n d not boots o r “ t a k k i e s ”. research protocol f o r t h e p u r p o s e s o f this s t u d y th e s am e pro to co l was followed as wa s u s e d by t h e g r o u p 1-injury i n c id e n c e (i.e. i n ­ jur y in t h e p r e s e n c e o f an o b v i o u s s u d ­ d e n p r e c i p it a t i n g ev en t) wa s low er th a n th e g r o u p 2 i n j u r y in c id e n c e (i.e. i n ju ry in t h e a b s e n c e o f an o b v i o u s s u d d e n p re c i p it a t i n g ev en t) for b o th t h e s t a n ­ d a r d (s t) a n d t h e s o r b o t h a n e (so) boot ty p es ( s t = 1,1% vs 16,0%; s o = 1,0% vs 9 , 8 % ). t h e d if feren ces in the g r o u p 1-injury in c id e n c e b e tw een the tw o bo ot t yp es ( s t = 1,1% vs s o = 1,0%) was n eg ligible a n d insig nifican t ( p > 0 ,1 ). t h e v a ria tio n in th e g r o u p 2 -i n j u ry in c id e n c e s h o w e d a significan t d if fe re n ce ( s t = 1 6,0% vs so = 9 ,8 % ; p=s0,05), as was t h e case for th e total r e c r u i t i n j u r y in c id e n c e ( s t = 1 7,1% vs so = 10,8%) b u t to a lesser d eg ree ( p < 0 , l ) . anatomical sites of injury per boot type g r o u p 1-i n ju ri es w e re s u s t a i n e d at on ly t h r e e an a t o m i c a l sites, n a m e ly th e an k le (s t = 3 3 ,3 % ), k n e e (s t = 6 6 ,7 % ; so g o r d o n el a l ,4 as r e g a rd s t h e defin ition o f an injury, classification o f injuri es a n d th e m e t h o d o f data c o l l e c t i o n . results recruit injury incidence and type of injury per boot type (table 1) t h e basic t r a i n i n g p r o g r a m m e was p e r ­ f o rm e d o v er a 10 w eek p e r i o d . d u r i n g p ract ic al t r a i n i n g re c r u i t s w ere s u b ­ jected to p h ys ic al c o n d i t i o n i n g follow ­ ing activities: • m ilita ry d rill ; • field t r a i n i n g ; a n d • p hys ic al tra i n i n g . drill tra in in g t o o k pla ce for o n e or m o r e p e ri o d s o f 40-55 m i n u t e s each p e r day. d u r i n g field t r a i n i n g re c r u i t s c o m ­ ple te d s t r e n u o u s nav ig atio na l a n d ro u te m a r c h e s o f 10-20 k m . in a c c o rd a n c e with fo o tw e ar re g u l a ti o n s re c r u i t s w o re boots t h r o u g h o u t dri ll a n d field t r a i n ­ ing. t h e p hys ic al t r a i n i n g p r o g r a m m e was followed for at least 4 p e r i o d s o f 40 m i n ­ utes eac h p e r w e e k o v e r t h e full 10 table 1: t he recruit injury incidence and type o f injury per boot type type boot type significance of by injury standard sorbothane fisher’s (n = 275) (n = 195) exact test n % n % group 1 3 1,1 2 1,0 n s group 2 44 16,0 19 9,8 p=s0,05 total 47 17,1 21 10,8 p<0,1 n = n o. o f in ju red recruits n = n o. o f re cru its p e r boot type s p o r t s m e d i c i n e vol s. n o i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nothing will give you i more x jm a t o l o g y u l t t o e s h m e n freedomtowalk,jump,runandwork 88/4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) preventative sports medicine = 33 ,3% ) a n d t hig h (s o = 6 6 ,7% ). g r o u p 2 -in ju ries ( f i g u r e 3) p ri m a ri l y affected t h e k n e e ( s t = 3 2 ,6% ; so = 3 8 ,1% ), low er leg ( s t a n d s o = 28 ,6% ) a n d achilles t e n d o n ( s t = 16,3%; so = 14,3%) for b o t h boot t yp es w h ile the re m a i n i n g an a t o m i c a l sites, n a m e ly the foot, heel, an k le a n d th ig h followed in f r e q u e n c y w i th a lower i n c id en ce. loss of basic-training time per boot type t h e dif fe re n ce in t h e total i n c id e n c e o f tra in in g d ay s lost as a re su lt o f exercise relat ed inju ri es p e r boot ty p e was n eg li ­ gibl e ( s t = 2 , 8 % ; s o = 2 ,2 % ). t h e i n ­ ci d en ce o f t r a i n i n g d ay s lost d u e to g r o u p 1-i n ju ri es was n o ta b l y less t h a n that for g r o u p 2 -in ju ries for b o th boot typ es ( s t = 8 , 2 % vs 9 1 , 8 % ; so = 6 , 3 % vs 93 ,7% ). f i g u r e 4 reflects the i n c i ­ d e n c e o f tra i n i n g d a y s lost d u e to g r o u p 2-inju ries p e r bo ot t y p e at the var io us a n ato m ical sites. d isc u ssio n t h e vast m a jo ri t y o f exer ci sere late d i n ­ ju rie s i n c u r r e d by re c r u i t s in this s tu d y w e r e inflicted in the a b s e n c e o f an o b ­ v ious s u d d e n p r e c i p it a t i n g even t a n d c a n , for p ract ic al p u r p o s e s , be re g a rd e d as o v e ru s e inju ri es. t h i s fin ding is in a c c o r d a n c e w i th th a t o f g o r d o n et al4 for s o u th a fr ic an a r m y re cr uits . in this s tu d y th e s o fared significantly b e tte r t h a n the s t ( s t = 16,0% vs so = 9 , 8 % ; p=£ 0 ,0 5) as re g a rd s t h e in c i­ d e n c e o f o v e ru s e inju ri es ( g r o u p 2). a n u m b e r o f re s e a r c h e r s 22 24 r e g a rd an ac­ c u m u l a t i o n o f m i c r o t r a u m a d u r i n g ste ­ r e o t y p e d , cyclic activities s u ch as r u n ­ n in g as a m a jo r etiological factor in the in c id e n c e o f o v e ru s e in ju ri es , whil e o th e r s 25 27 su gg es t tha t a lack o f shock a b s o r b ti o n in tra i n i n g fo otw ear a c c e n ­ tu a te s thi s p r o b l e m . t h e effective f u n c ­ t io n i n g o f t h e s h o c k a b s o r b i n g s o r b o ­ t h a n e in n e r so le in t h e so as o p p o s e d to the s t in this study, t h u s e n co u ra g es s u p p o r t for t h e a b o v e o p i n i o n s . 22 77 t h e an a to m ic a l d is t r i b u t i o n o f g r o u p 2-i nju ri es in this s t u d y s h o w s sim ila ri­ ties w i th b o th civili an28'31 a n d mili ta ry 2-4'7 p o p u l a t i o n s w h e r e the k n e e , incidence of training-days lost (%) 50 4 0 30 20 10 standard boot v / a sorbothane boot thigh foot heel ankle achilles lower leg knee anatomical site figure 4: a n a t o m i c a l d is t r i b u t i o n o f tra i n i n g days lost d u e to g r o u p 2 in j u ri e s p e r bo ot typ e s p o r t s m e d i c i n e vol s. n o 1 thigh foot heel ankle achilles lower leg knee anatomical site figure 3: a n a t o m i c a l d i s t r i b u t i o n o f g r o u p 2-inju ri es p er bo ot typ e incidence of injury (%) standard boot v '/ a sorbothane boot r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) preventative sports medicine lower leg a n d achilles t e n d o n suffered the h ig h es t i n c id e n c e o f o v e r u s e injury, c o m p a r e d to o t h e r an a t o m i c a l sites o f the lower e x trem itie s. a l t h o u g h the so s h o w e d low e r overall o v e ru s e in ju ry in­ c id en ce t h a n the s t , it d id ho w ev er have a h ig h e r in c id e n c e o f g r o u p 2-knee inju ri es t h a n the s t ( s t = 3 2 ,6 % vs so = 3 8,1% ). t h i s co u ld p oss ib ly b e at­ t r i b u t e d to t h e d es ig n o f t h e so inn er sole ( f i g u r e 2), w h e r e t h e b u i l d u p o f the m e d ial l o n g itu d in a l a r c h may have c au s ed an al ter ed foot po si tio n in a r e ­ crui t w ith n o foot a b n o r m a l i t y . 34 such an i n d u c e d an a to m ic a l m a la li g n m e n t co u ld have p r e d i s p o s e d th e w e a r e r to in ju ry in t h e area o f the k n e e . 26-3233 w h i l e th e k n e e s u s t a i n e d the hig hes t g r o u p 2 i n j u r y i n c id en ce for b o th boot typ es in this s t u d y ( f i g u r e 3), low er leg inju ri es ca u s e d t h e gre a te s t loss o f t r a i n ­ ing d ay s ( f i g u r e 4). t h i s o b se rv a ti o n i m p lie s that o v e ru s e o f the lower leg w ere o f a m o r e serious n a t u r e t h a n kn ee injuries . t h i s findin g is in a g re e m e n t w ith a p re v i o u s s tu d y 4 a m o n g so u th a f­ rican a r m y recruits. o n ly a few stu d ies hav e b e e n p u b ­ lis hed th a t specifically c o n c e n t r a t e on i m p r o v i n g the s h o c k a b s o r b i n g c a p a ­ bilities o f t h e c o m b a t b o o t , in an a t ­ t e m p t to re d u c e the in c id e n c e o f inju ry a m o n g re c r u i t s d u r i n g basic t r a i n ­ i n g . 81013 in m a k i n g a b io m e c h a n i c a l c o m p a r i s o n b e t w e e n r u n n i n g shoes a n d c o m b a t b o o ts , d e m o y a 10 f o u n d tha t ca­ d ets w e a ri n g c o m b a t b o ots ex p e ri e n c e d m a x i m u m vertical fo rce re a d i n g s o f o v e r 3 tim es b o d y w e i g h t , w h ile th e use o f i ns erts (s ar an ) w i th i n the bo ot s ig n i­ ficantly i m p r o v e d the c u s h io n i n g re ­ sp o n s e to im p a c t . m i l g r o m et a ln c o n ­ d u c t e d a s t u d y to ev alu ate th e effect o f a s h o c k a b s o r b i n g o rt h o t i c ( p p t l a n g e r ) on t h e i n c id e n c e o f stress fra c tu re s in m ilita ry re c r u i t s . t h e i r fi n din g s s h ow ed tha t the co n c e p t o f o rt h o t i c p ro p h y la x is significantly low ered t h e in c id e n c e o f femoral str es s frac tu re s w h ic h th e y c o n ­ s id e r e d to be pote n tiall y the m o s t d a n g ­ e r o u s ; d u e to th e ir t e n d e n c y to b e “ si­ l e n t ” for long p e ri o d s a n d t h e ir risk to ev olve int o d is p laced stress f r a c t u r e s . 13 f o r th e p u r p o s e o f d e t e r m i n i n g w h e t h e r fe w er inju ri es w o u ld o ccu r f ro m u sing c u s h i o n e d inner sole s (s p e n c o a n d p o r o n ) , s m i th et ap m o d ­ ified th e b o ot u s ed for all tra i n i n g and m a r c h i n g by t h e u n it e d states coast g u a r d . t h e i r fin dings s h o w e d th a t the c o n tr ol g r o u p has th e hig h es t i n j u ry i n ­ cid e n c e (6 2 ,5 % ) d u r i n g basic t r a i n i n g , 9 fo llowed b y the p o r o n a n d sp en co 10 g r o u p s w i th 2 6 % a n d 14,2% r e s p e c ­ tively, w h il e th e overall co m f o r t o f the bo ot was also e n h a n c e d wi th the use o f th e s h o c k a b s o r b i n g inn er so le s. co nclusion t h e re su lts o f o u r a n d t h e a b o v e s t u d ­ ies810-13 in d i c a t e th a t an i m p r o v e m e n t in the s h o c k a b s o r b i n g cap ab ili ties o f the c o m b a t b o ot is r e q u i r e d , if t h e hig h i n ­ c id en ce o f i n j u r y a m o n g r ecr u its d u r i n g basic t r a i n i n g 1'4 is to b e r e d u c e d . a l­ t h o u g h d if fe re n ce s in re search p ro to co ls a n d the m a te ri al u sed in th e se s tud jes8.io,i3 d isqual ifies an a c c u r a te c o m ­ pa rison w ith each o t h e r a n d with th e re ­ sults o f this stud y, a m e a s u r e o f c o rr elation can b e d e d u c e d . i n this a n d the s tu d ies o f d e m o y a , 10 m i l g r o m et a ln a n d s m i th et a l,g the m o d ificatio n o f pla cing s h o c k a b s o r b i n g in n er so les w ith in c o m b a t b o o t s , r es u lte d in a lower in c id e n c e o f injury, c o m p a r e d to the s t a n d a r d c o m b a t b o o t, c o n fi rm i n g the su ccess o f this p r o p h y l a c t i c a p ­ p roac h. r e f e r e n c e s 1. b e n s e l c k . t h e e f f ec t s o f t r o p i c a l a n d l e a t h e r c o m b a t b o o t s o n l o w e r e x t r e m i t y d i s ­ o r d e r s a m o n g m a r i n e c o r p s r e c r u i t s . c l o t h ­ i n g , e q u i p m e n t a n d m a t e r i a l s e n g i n e e r i n g l a b o r a t o r y , n a t i c k a r m y l a b s . t e c h n i c a l r e p o r t n o . 7 6 4 9 c e m e l , 1976. 2. k o w a l d . n a t u r e a n d c a u s e s o f i n j u r i e s in w o m e n r e s u l t i n g f r o m a n e n d u r a n c e t r a i n i n g p r o g r a m . a m j sp orts m e d 19 80 ; 8: 2 6 5 269. 3. s t a c y r j , h u n g e r f o r d r l . a m e t h o d t o r e ­ d u c e w o r k r e l a t e d i n j u r i e s d u r i n g b a s i c r e ­ c r u i t t r a i n i n g in t h e n e w z e a l a n d a r m y . m i li tm e d 19 84 ; 149: 3 1 8 3 2 0 . 4. g o r d o n n f , h u g o e p , c i l l i e r s j f . t h e s o u t h a f r i c a n d e f e n c e f o r c e p h y s i c a l t r a i n ­ i n g p r o g r a m m e . p a r t i i i . e x e r t i o n r e l a t e d i n j u r i e s s u s t a i n e d at a n s a d f b a s i c t r a i n i n g c e n t r e . 5 a f r m e d j 1986; 69: 4 9 1 4 9 4 . 5. b l a c k j r . s t r e s s f r a c t u r e o f t h e fo ot in fe m a l e s o l d i e r s : a t w o y e a r s u r v e y . m i li i m e d 1 9 8 2 ; 1 4 7 : 8 6 1 8 6 2 . 6. j a g o d a d . f r i c t i o n b l i s t e r p r e v e n t i o n s t u d y in a p o p u l a t i o n o f m a r i n e s . m ilil m e d 1981; 146:42. 7. r e i n k e r k a , o z b u r n e s. c o m p a r i s o n o f m a l e a n d f e m a l e o r t h o p a e d i c p a t h o l o g y in b a s i c t r a i n i n g . m ilil m e d 19 79 ; 144: 53 25 3 6 . s m i t h w , w a l t e r j , b a i l e y m . e f f e c t s o f i n ­ s ol e s i n c o a s t g u a r d b a s i c t r a i n i n g f oo twe ar . j a p a 1 9 8 5 ; 7 5 : 6 4 4 6 4 7 . c a v a n a g h p . the r u n n in g s h o e b o o k . c a l i ­ f o r n i a : a n d e r s o n w o r l d , 1980. d e m o y a r g . a b i o m e c h a n i c a l c o m p a r i s o n o f t h e r u n n i n g s h o e a n d t h e c o m b a t b o o t . m i li tm e d 1 9 8 2 ; 147: 3 8 0 3 8 3 . j o n e s b h . o v e r u s e i n j u r i e s o f t h e l o w e r e x ­ t r e m i t i e s a s s o c i a t e d w i t h m a r c h i n g , j o g g i n g , a n d r u n n i n g : a r e v i e w . m i l i t m e d 1983; 148: 7 8 3 7 8 7 . 12. s o u t h a f r i c a n a r m y o r d e r : p h y s i c a l t r a i n ­ i n g in t h e s a a r m y . g s 1 / 1 03 /8 7. 1987. 13. m i l g r o m c , g i l a d i m , k a s h t a n h , et al. a p r o s p e c t i v e s t u d y o f t h e ef fect o f a s h o c k a b s o r b i n g o r t h o t i c d e v i c e o n t h e i n c i d e n c e o f s t r e s s f r a c t u r e s i n m i l i t a r y r e c r u i t s . fool & a n k l e m s ; 6 : 1 01 10 4 . 14. s o u t h a f r i c a n b u r e a u o f s t a n d a r d s tes t r e ­ p o r t : d i f f e r e n t t y p e s o f b o o t s i s s u e d f o r a w e a r t ria l d u r i n g d e c e m b e r 1984. r e p o r t n o . c a b 4 6 1 / 6 2 1 3 0 , p r e t o r i a 1 98 5 ; 1-3. 15. j a h n w t . v i s c o e l a s t i c o r t h o t i c s : s o r b o ­ t h a n e u . j f o s p t 19 83 ; 5: 174. 16. h i l e s m . s o r b o t h a n e : a v i s c o e l a s t i c p o l y ­ m er . a u r o r a , o h i o : i . e . m . o r t h o p a e d i c s , 1983. 17. h o w g a t e p g . t h e b a s i c d y n a m i c s o f s o r b o ­ t h a n e . s o r b o t h a n e c o n g r e s s , m a y , 1984. s o r b o t h a n e m a n u f a c t u r e r e s r e f e r e n c e l i­ b r a r y , 1 9 8 4 ; 2 3 . 18. j o h n s o n g r . engineering in m edicine. 1986; 1 5 : 1 1 7 1 2 2 . 19. c i n a t s j , r e i d d c , h a d d o w j b . a b i o m e ­ c h a n i c a l e v a l u a t i o n o f s o r b o t h a n e . c lin or thop 1 9 8 7 ; 2 2 2 : 2 8 1 2 8 8 . 20. b u r t o n r d , g r e y p j . e n e r g y d i s s i p a t i o n u s ­ i n g n o v e l p o l y u r e t h a n e s . i n t e r n a t i o n a l c o n ­ f e r e n c e “ p o l y m e r s in d e f e n c e ”, m a r c h 1987. s o r b o t h a n e m a n u f a c t u r e r s r e f e r e n c e l i br a r y , 1 9 8 7 ; 4 . 21. p h y s i c a l t r a i n i n g f o r m a l e m e m b e r s o f sa a r m y . d e s c r i p t i v e p h o t o a l b u m . s a a r m y h e a d q u a r t e r s : 1 m i l i t a r y p r i n t i n g u n i t , 1985. 2 2. p e t e r s o n l , r e n s t r o m p. s p o r t i n j u r i e s . t h e i r p r e v e n t i o n a n d t r e a t m e n t . j o h a n n e s ­ b u r g : j u t a a n d c o m p a n y , 1986. 2 3. s p e r r y n p n . s p o r t s a n d m e d i c i n e . l o n d o n : b u t t e r w o r t h s , 1985. 24. s m i t h n j , s t a n i t s k i c l . s p o r t s m e d i c i n e . a p r a c t i c a l g u i d e . p h i l a d e l p h i a : w b s a u n ­ d e r s , 1987. 2 5. n o a k e s t . l o r e o f r u n n i n g . c a p e t o w n : o x f o r d u n i v e r s i t y p r e s s , 1985. 26. m c k e n z i e d c , c l e m e n t d b , t a u n t o n j e . r u n n i n g s h o e s , o r t h o t i c s a n d i n j u r i e s . s p o r is m e d 1 9 8 5 ; 2 : 3 3 4 3 4 7 . 2 7 . n i g g b m . biom echanics o f r u n n in g shoes. c h a m p a i g n : h u m a n k i n e t i c s , 1986. 28. j a m e s s l , b a t e s b t , o s t e r n i g l r . i n j u r i e s t o r u n n e r s . a m j s p o rts m e d 197 8; 6: 4 0 5 0 . 29. k r i s s o f f w b , g e r r i s w d . r u n n e r ’s i n j u ­ ri es . p h y ss p o rlsm e d 1979; 7: 5 5 6 4. 30. c l e m e n t d b , t a u n t o n j e , s m a r t g w , m c n i c o l k l . a s u r v e y o f o v e r u s e r u n n i n g i n j u ­ ri es . p h y ss p o rlsm e d 1980 ; 9: 4 7 58 . 31 m a u g h a n r j , m i l l e r j d b . i n c i d e n c e o f t r a i n i n g r e l a t e d i n j u r i e s a m o n g m a r a t h o n r u n n e r s . b r j s p o r i s m e d 19 81 ; 17: 1 6 216 5. 32. l u t t e r l d . f o o t r e l a t e d k n e e p r o b l e m s in t h e l o n g d i s t a n c e r u n n e r . f oot & a n k le 198 0; 1: 113 -1 1 6. 33. s u b o t n i c k s i. f o o t o r t h o s e s : a n u p d a t e . p h yss p o rlsm ed 19 8 3; 11: 10 31 09 . --------------------------------------------------------------- 9s p o r t g e n e e s k u n d e vol 5. n r i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition energy value of food m faber energyintake t h e m a in d if feren ce b e t w e e n the a t h ­ letes die t a n d t h e die t o f th e g en eral p o p u l a t io n can be f o u n d in the level o f en e rg y int ak e. e n e r g y r e q u i r e m e n t s o f the at h le te d e p e n d no t on ly on the type o f ex ercise, b u t also on t h e tim e u sed p e r f o r m i n g the activity. in o t h e r w o r d s , the en e rg y r e q u i r e m e n t s m a y v ar y over tim e a c c o rd i n g to t h e p hys ic al train in g p r o g r a m m e o f th e ath le te . to m a in t a i n good p e r f o r m a n c e , the e n e r g y inta ke m u s t e q u al t h e e n e r g y e x p e n d i t u r e . t h i s will re su lt in t h e b o d y w eig h t r e ­ m a in i n g m o re o r less sta ble. t h e b o d y weig ht o f an at h le te can be an in d icatio n w h e t h e r he is c o n s u m i n g sufficient e n ­ ergy. e n e r g y i m b a l a n c e will be e v ide nt by ch an g es in b o d y w eig ht. if en erg y im b a l a n c e o c c u r s , t h e in d i v id u a l will eithe r lose or gain w eig ht. i f th e en erg y c o n te n t o f th e food in g es ted is less th an the en e rg y o u t p u t , i.e. if t h e en e rg y bal ­ an ce is n e g a tiv e , e n d o g e n o u s stores n a m e ly g ly co g en , fat a n d b o d y p ro te in are utilised a n d the i n d iv id u a l loses wei ght . if the e n e r g y v al ue o f the food intak e exce eds e n e r g y e x p e n d i t u r e , the b ala nce is po sitive a n d e n e r g y is store d as a d ip o s e tis sue a n d the in d iv id u al g ai ns w ei g ht. e a c h k il o g ra m o f ad ipo s e tissue (fat) r e p r e s e n t s th e sto ra ge o f m ie k e f aber research in stitu te fo r n u tn d o n a l disease m ed ica l research council, t y g e r b e r g . a b o u t 7000 kcal (2 9 3 00 k j) . i f th e a t h ­ lete is o v e rw e ig h t a n d s h o u l d lose w e i g h t , a ste ad y w e i g h t loss o f 0,5 to 1,0 kg p e r w e e k is r e c o m m e n d e d . to achieve this wei g ht loss, the e n e r g y d e ­ ficit s h o u l d be b e t w e e n 3500 a n d 7000 kcal( 14650 a n d 29300 k j ) per w ee k. where does th e energy in the diet come from? t h e en e rg y value o f t h e diet is ex p res s ed in e ith e r calories (kcal) o r kilojoules ( k j ) . o n e kcal e q u als 4 , 1 8 6 k j . t h e e n ­ erg y v al ue o f dif fe re n t food i te m s is d e ­ t e r m i n e d by t h e c a r b o h y d r a t e , p ro te in a n d fat c o n te n t o f food. a lcoho l m a y also c o n t r i b u t e to the e n e r g y c o n te n t o f t h e d i e t . 1 g c a r b o h y d r a t e s u p p l i e s 4 kcal( 17 k j ) 1 g p ro te in s u p p l i e s 4 kcal( 17 k j ) 1 g fat su p p lies 9 kcal(37 k j ) 1 g alcohol su p p lies 7 kcal (29 k j ) a calo rie is a calo rie, w h e t h e r it co m e s fr o m c a r b o h y d r a t e , p r o te in o r fat. m o s t o r d i n a r y foods are c o m b i n a t i o n s o f p r o ­ tein, c a r b o h y d r a t e , fat, a n d it also c o n ­ tains v a ria b le a m o u n t s o f w a t e r (s o m e as h ig h as 9 0 % ). it also c o n ta in s v it a m in s a n d m in era ls . f o o d s th a t hav e a hig h w a t e r c o n t e n t , s u c h as fruit a n d ve g­ et ab les, h av e small q u a n t i t i e s o f p r o ­ te in, c a r b o h y d r a t e s a n d fat a n d are th e re fo re relativ ely low in calories. f o o d s w h i c h c o n ta in little or no water, eg s u g a r (with p le n t y c a r b o h y d r a t e s ) , oil a n d fats (with p le n t y fat) ar e loaded with energy. a g re at d is a d v a n t a g e o f m a n y o f the e n e r g y loa de d foo ds is that th e y often p ro v id e little m o r e t h a n e n ­ ergy. a n i m b a l a n c e b e t w e e n th e en erg y intak e a n d n u t r i e n t in t a k e is th e re fo re the result. t h e fact th a t food co n ta in s w ater can lead to m a n y m i s c o n c e p t io n s c o n c e r n i n g t h e energy, p r o te in a n d c a r b o h y d r a t e c o n te n t o f food. f o r e x a m p l e , m e at is k n o w n as a hig h p r o ­ tein food. t h i s d o es n o t m e a n th a t 30 g o f m e at eq u als 30 g o f p r o te in . in fact, 30 g m e at s u p p l i e s on the a v era g e on ly 7 g p r o te in a n d 5 g fat. t h e r e m a i n i n g 18 g (60 %) is m o s t ly water, w h ic h s u p ­ plies no energy. e v en w h e n all t h e vis­ ible fat is re m o v e d fro m m e a t , it still co n ta in s v a ria b le p r o p o r t i o n s o f inv is ­ ible fat w h ic h are closely as sociated w i th o th e r c o n s t i t u e n t s in an e m u l s i o n or as p a rt o f th e tissue. w h e n p l a n n i n g an ea tin g p a t t e r n , e n e r g y in ta k e is no t the on ly d e t e r m i n i n g factor. f a c to r s s u c h as p ro te in n e e d s , v it a m in a n d m in era l re ­ q u i r e m e n t s a n d ad v e rs e effects o f high fat i ntak es s h o u l d also be t ak en into c o n s id e ra ti o n . a b a l a n c e d die t, c o m p o s e d o f t h e t h r e e m a c r o n u t r i e n t s ( c a r b o h y d r a t e s , p r o te in a n d fat) p lu s vi­ t a m i n s a n d m i n e r a l s , is n eces s ary for p r o p e r n u tr i t io n . it is q u it e p o ss ib le to c o n s u m e a d e q u a t e a m o u n t s o f energy, b u t b ecau s e o f p o o r food ch o ic es, be m a l n o u r i s h e d d u e to ce rt ai n n u t r i e n t deficiencies. it m u s t be k e p t in m i n d that fats a n d s u g a r do no t c o n ta in p r o ­ tein a n d m i n e ra l s . w h e n t h e y c o n s ti t u t e a large p r o p o r t i o n o f t h e total e n e r g y i n ­ tak e, t h e re is a d a n g e r th a t o t h e r n u t r i ­ ent n e e d s will not be m e t. a s s u m i n g tha t en e rg y n e e d s ar e m e t , t h e follo wi ng en e rg y d i s t r i b u t i o n is r e c o m m e n d e d : • at least 5 5 % o f the e n e r g y s h o u l d be s u p p l i e d by c a r b o h y d r a t e s ; • 12-15% o f th e en e rg y s h o u l d be s u p ­ plied by p r o te in ; 10 ---------------------------------------------------------s p o r t s m e d i c i n e vols. n o 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition • fat s h o u l d n o t ex ce ed 3 0 % o f the t o ­ tal e n e r g y int ak e. t h e q u a n t i t y o f food is defi n it el y no i n ­ dication o f e n e r g y intak e. to inc re as e the b u lk o f th e d ie t, foods w i th a low er en erg y d e n s it y (fe wer k c a l / 100 g) ca n be c o n s u m e d . a n e x a m p l e o f a food ite m with a low en e rg y d e n s it y is an ap p le (58 k c a l / 1 oog) c o m p a r e d to ch oco la tes wh ic h has a hig h e n e r g y d e n s it y (520 k c a l / 1 oog). t h e g re a te s t pitfall in en e rg y int ake is the fats o n e is not a w a r e o f (in ­ visible fats), s u c h as fat in fri ed fo ods, me lted b u t t e r in ho t v e g e t a b le s , cre a m in s o up s a n d s au ces , salad d r e s s in g s a n d rich b a k e d p r o d u c ts . f o o d s ca n be g r o u p e d t o g e t h e r a cc o rd in g to t h e i r c a r b o h y d r a t e , p r o ­ tein a n d fat co n te n t . e a c h g r o u p c o n ­ tains foods th a t ar e m o r e o r less alike. t h e a v era g e m a c r o n u t r i e n t c o n te n t for these g r o u p s are s u m m a r i s e d in th e fol­ lowing table. t h i s tab le can be u sed as a guid el ine in p l a n n i n g t h e d aily en e rg y intake. table 1: kcal a n d m a c r o n u t r i e n t c o n te n t o f foods q u a n tity c h o (g) p ro te in (g) f a t (g) e nergy (kcal) s tarch/bread 30g b read or 125 m l cereal or 125 m l pasta* or 125 m l grain* o r 125 m l rice* 15 3 trace 80 lean m eat 90 g • 21 9 165 m edium -fat m eal 90 g 21 15 225 h igh-fat meal 90 g 21 24 300 vegetables 125 m l cooked or 250 m l raw 5 2 25 f ru it 125 m l fresh fruit o r 125 m l juice or 62 m l d ried fruii 15 60 skim m ilk 250 m l 12 8 trace 90 low-fat m ilk 250 m l 12 8 5 120 w hole m ilk 250 m l 12 8 8 150 fai 5 g 1 teaspoon • 5 45 * cooked values s p o r t g e n e e s k u n d e vol s. n r i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) die waarde van pre-seisoensevaluering en post traumatiese fisieke rehabilitasie ddj malan in leid ing d ie afgelope dekade is die sportwereld en deelname aan fisieke aktiwiteit ge kenmerk deur die “fitness boom ” wat voorgekom het. n ie alleen het die nuwe bedrywe tot stand laat kom nie, maar ook ’n deels onverwagte uitdaging aan die sportgeneeskundige professie gestel. d ie voorkoms van beserings tydens deelname aan sport en fisieke aktiwiteite het weens die deelnemerstal bykans maandeliks toegeneem . gepaardgande hiermee is die sport geneeskundiges en lateraan ook die oe fenkundiges met ’n andersoortige bena dering ten opsigte van die beoordeling en behandeling van beserings tydens deelname gekonfronteer. gedurende die sestigeren sewentigerjare het die klem hoofsaaklik geval op die diagnose en behandeling van akute beserings, ter wyl die analise van die voorkom ende as pekte weinig aandag geniet het (stanish, 1984:1). hierdie aanvanklike gebrek en eensydige benadering het egter bygedra tot die meer professionele spanbenader ing in die voorkom ende en rehabilite rende fases van sportbeserings. op verskeie terreine van sport en fisieke ak­ tiwiteit is doelgerigte opleidingspak kette ter verbetering van afrigters en programleiers se basiese kennis oor oe fenkundige aspekte tydens deelnam e, daargestel. binne ’n bestek van sowat 5 jaar het daar veral op die terrein van die oefenkundige aspekte, ’n meer bewuste en kundige benadering voorgekom . d it is egter ook waar dat die gevare verd r d d j malan instituut v ir biokinetika departement menslike bewegingskunde p u v ir c h o s p o r t s m e d i c i n e v o l 5. n o i bonde aan oefenprogram voorskrif deur verskeie aanbieders geignoreer word weens die gebrek aan opleiding, met ’n gevolglike hoe insidensie van beserings wat by diesulke persone se groepe voor kom. d ieselfde tendens word volgens stanish (1984:1) ook in kanada aange tref, waar daar selfs meer aandag aan opleiding gegee word. selfs op skool vlak word daar tans ’n voorkomende benadering tot fisieke aktiwiteitsdeel name gevolg. ’n verdere uitvloeisel van hierdie toe nem ende probleem waarmee sportge neeskundiges en oefenkundiges worstel, is die daarstelling van semi naargeleenthede waar kundiges ge dagtes kan uitruil en kennis oor die voorkoming en behandeling van beser­ ings kan oordra. d ink maar net in hier­ die geval aan die totstandkom ing van ons eie sportgeneeskundige vereniging, asook die werksaamhede van savslor (suid-afrikaanse vereniging vir sportwetenskap liggaamlike op voedkunde en rekreasiekunde) op die terreine van o efenkunde en biokinetika in die geval van laasgenoemde organisa sie. in m eeste opsigte is die dienste van die multidissiplinere span op die ge sondheidsorg van die deelnem ers inge stel. beserings in sport en fisieke aktiwiteit toon groot w isseling. kontaksport is al gem een bekend vir die hoe insidensie van beserings, maar niemand het ge dagte gehad dat die deelnam e aan aero biese dansoefeninge so ’n magdom be­ serings tot gevolg sal he nie. wat in hierdie twee uiterstes van aktiwiteite veral opvallend is, is dat die voorkoms van dieselfde tipe besering, aan totaal verskillende oorsake toegeskryf kan word. so byvoorbeeld kan ’n swak fisieke spiervermoe in die geval van die rugbyspeler aanleiding gegee het tot die besering, terwyl onkundigheid oor programuitvoering in die geval van die aerobiese dans deelnem er as oorsaak voorgehou kan word. daar is bereken dat gedurende 1983 sowat 20% van die amerikaanse be volking aan hardloopaktiwiteite deelge neem het (stanish, 1984:1). ’n verdere 10% het aan ’n verskeidenheid ander sport en fisieke aktiwiteite deelgeneem wat potensieel tot beserings kon aan­ leiding gee. d it mag dalk die indruk van ’n baie gesonde gem eenskap gee, wat wel ook waar is, maar weens die toe name is beseringsinsidensie blyk dit eerder ’n “beseerde” gesonde gem een­ skap te wees. op geen w yse is m edici in staat om bo-en-behalwe hul normale be­ handeling van siektetoestande ook nog met die behandeling van beserings ty­ dens fisieke aktiwiteit vol ten hou nie. o p een o f ander wyse genoodsaak dit ’n profilaktiese benadering. d eelnam e aan sport en selfs fisieke aktiwiteite in die algem een kan soms bom enslike eise aan die fisieke vermoe van die liggaam stel. d it het daartoe by­ gedra dat die voorbereiding van veral sportlui meer gesofistikeerd en gespe sialiseerd geraak het, vanwee die meer wetenskaplike benadering van afrigters. d it is oor die afgelope 40 jaar sterk aan gespoor en ondersteun deur ’n “navor singsontploffing” op die terrein van die sportgeneeskunde. ten spyte van die meer wetenskaplike benadering van sportafrigting, is dit by­ kans onm oontlik om die sportdeel nemer se “spook” ’n sportbesering tydens deelnam e weg te hou. ongeag na watter sportsoort gekyk w ord, bly die traumatiese ervaring van ’n besering die grootste terugslag wat ’n deelnem er kan ervaar. suid-afrika gaan deels nog gebuk onder afrigters/programleiers wat nie vatbaar vir “inm enging” is nie en so doende hulself as alwetend beskou. sor ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) danige benadering weerspieel ’n gebrek aan kundigheid en stel h u lself en onge lukkig ook die sportlui aan gebrekkige vordering en ander problem e bloot. d ie teenoorgestelde is egter ook waar. d ie afrigter/programleier beskou hulself as spesialiste op hul terrein, maar ag dit nodig om ander ondersteunende kun diges te nader ter w ille van die voordele daarvan aan die deelnem ers. sodanige wisselwerking is ’n direkte aankno pingspunt tot die profilaktiese benade­ ring tot beserings tydens deelnam e aan sport en fisieke aktiwiteit. pre-seisoense valuerin g verskeie wetenskaplikes (o.a. h unter et al., 1979:205; n o b le , 1980:12; watson, 1981:47 & rice, 1984:192) maak m eld­ ing van die verskeidenheid van wyses waardeur beserings tydens deelname voorkom kan word. voorstelle in hier die verband het gewissel van wetenskap like opleiding van afrigters/program leiers tot verandering aan die reels van die spel. een van die uitstaande faktore wat in die navorsing na vore gekom het, is die eenstem m igheid oor die belang rikheid en waarde van pre-seisoenseva luering. n ie alien word dit as ’n voorko mende maatreel gestel nie, maar hou dit ook bepaalde voordele in indien die deelnemer later beseer sou raak. appen en duncan (1986:232) ver klaar dat pre-seisoensevaluering a riglyn gebruik kan word om die deelnem er se gereedheid vir deelnam e aan ’n bepaalde sport te kan bepaal. h ieruit kan afgelei word dat die deelnem er se fisieke toe rusting net so belangrik is as die toerus ting waarmee die aktiwiteit beoefen m oetword. pre-seisoensevaluering dien ook as metode waardeur “swak skakels” in die fisieke m ondering van deelnem ers ge identifiseer kan word. sodoende kan daar dan met die korrekte inoefen ingsm etodes, ’n regstelling van die te kortkominge gemaak w ord, waardeur die m oontlike oorsaak van beserings verminder kan word. watson (1981:417) beklem toon die voorafbepaling van sportdeelnem ers se fisieke toestand. in hul navorsing is 0/15 en 0/16 rugbyspelers aan ’n fisieke pre seisoensevaluering onderwerp. sy be vinding was dat die deelnem ers se krag, grootte en sukses tydens deelnam e nie as waarborg moet dien vir die afwesig heid van fisieke tekortkom inge nie. d ie navorsing het duidelik gedui op die noodsaaklikheid van preseisoenseva luering reeds op jong ouderdom , ten einde individuele verskille te kan aandui asook om op daardie ouderdom reeds fisieke tekortkom inge te kan regstel. watson (1981:421) beklem toon die noodsaaklikheid na evalueringsm etodes wat vinnig en effektief deur afrigters/ programleirs uitgevoer kan word. rice (1984:192) m eld dat aanbevelings deur die sportgeneeskundiges en sportvere nigings in die v .s .a . daarop is om alle deelnem ers aan sport op hoerskool vlak, jaarliks aan ’n pre-seisoensevaluer­ ing bloot te stel. in hul ondersoek is vasgestel dat 70% van die persone wat na ’n jaar ge-herevalueer is, bepaalde diskwalifiserende probleme vertoon het, waarvan 55% een o f ander vorm van m uskulo-skeletale o f ortopediese probleem was. strydom (1985:7) verwys ook na die neiging dat afrigters meer spesifiek is in hul voorbereidingsm etodes van sport­ lui. t w ee provinsiale rugbyspanne het in 1984 ’n poging aangewend om hul spelers aan pre-seisoensevaluering te onderwerp. weens die belangrikheid van die kom petisie en die gesindheid van die spelers is die navorsing nie na wense voltooi nie, en is daar nog w einig inligting hieroor beskikbaar. n avorsing deur die instituut van sportnavorsing en -o pleiding het in 1985 resultate verkry wat dui op die afname van fisieke vermoe namate die seisoen verloop het. sonder preseisoensevaluering sou soda­ nige afleiding nie gemaak kon word nie. uit gesprekke met m edici en ortope diste het dit geblyk dat preseisoense­ valuering van groot waarde is in die diagnose van ’n beseerde deelnemer. d it is egter nie haalbaar om sodanige evalu ering op elke deelnem er toe te pas nie, maar kan dit aanvanklik veral op deel­ nemers van hoe standaard toegepas word ten einde ’n verwysingsraamwerk daar te stel. op verskeie geleenthede is die opm erking al gemaak dat die evalu ering van ’n besering meer doeltreffend sou gewees het indien die resultaat van ’n preseisoensevaluering bekend was. so byvoorbeeld word, waar m oontlik, by 1 mil. hospitaal ’n pre-operatiewe evaluering gedoen van pasiente met ’n besering, ten einde fisieke rehabilitasie meer doeltreffend te kan maak. d ie noodsaaklikheid van pre-seisoen­ sevaluering blyk duidelik uit die boge noem de argumente en resultate. ter op som ming kan die waarde van sodanige evaluering net weer kortliks aangestip word. • d it dien as m etode waardeur fisieke tekortkom inge waargeneem kan word; • identifisering en rem ediering van “swak plekke” kan daartoe bydra dat die voorkoms van beserings verm in­ der kan word; • d it stel die afrigter/programleier in staat om meer doelgerig met die inoefeningsprogram te handel; • d it dien as wyse waardeur delnem ers op individuele grondslag beoor deel kan word en programvoorskrif daarvolgens kan geskied; • d it dien as basis waarteen opvolge valuerings vergelyk kan word; en • tydens rehabilitasie dien dit as norm waaraan die herstelproses meer objektief beoordeel kan word. post-traum atiese fisieke rehabilitasie dit is nie die oogm erk van hierdie lesing om verdiep te raak in die rehabilitasie prosedures en resultate van ’n enkele o f wye verskeidenheid van muskulo-skele tale problem e nie. d ie doel is meer op die waarde wat post-traumatiese fisieke rehabilitasie vir sportlui in die algemeen in h o u ,u it te lig. soos in die geval van ’n multidissipli nere spanbenadering in die voorkoming van beserings, behoort dieselfde weg ook opgegaan te word in die rehabilita­ sie van ’n beseerde deelnemer. d ie om vang van deelnam e, die toename in be seringsinsidensie en die kom pleksiteit van rehabilitasie na die besering ge noodsaak sodanige benadering. verskeie sentra in ons land kan as dui delike voorbeeld van die suksesvolle samewerking van m edici, fisioterapeute en biokinetici in die rehabilitasie van be seerdes voorgehou word, ’n praktiese voorbeeld van spanwerk in hierdie vers p o r t g e n e e s k u n d e v o l s . n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sportbeserings b an d ka n in d ie re h a b i l i t a s i e s e n t r u m by i mil. h o s p . gesie n w o r d . d i e s p an be haal u it s t e k e n d e res u lta te m e t beseerd e p asie nte wat m u s k u lo s k e l e t a le b e s e r ­ ings o p g e d o e n het. t y d e n s ’n p e r s o o n l i k e b es o ek aan die vsa is gev in d d a t so o r tg ely k e d ie ns te aa n ver skei e s p o r t k l u b s en p ri v a a tp ra k tyke g el ew er w o r d . dit is nie v r e e m d o m o.a. by va n die a m e r ik a a n s e v o e tb a l s p a n n e so ’n s p o r t g e n e e s k u n dig e s p a n aan te t r e f nie. ten voile toe g e ru s te r e h a b i li t a s ie k a m e r s w a a r ak u te en finale fase fisieke re h ab ili tas ie uitge v o er w o r d , is aa n die o r d e van die die dag. die w a a r d e va n re h ab ili tasie vir h ie rd ie s p o r t s p a n n e m o e t gelees w o rd in d ie effektiwiteit w a a r m e e r die sp elers tot die spel t e ru g g e p l a a s w o r d , ’n alge m e n e u i t d r u k k i n g is d at die sp ele r in ’n b e t e r to e stan d aan die s p an t e r u g b e s o r g w o rd as w aarin hy was v o o r d ie b e s e r ­ ing. e en van die h o o f d o elste lli ngs van r e ­ habili tasie is o m die p ers o o n se funsio nele v e rm o e te h er stel. in d ie geval van profe ssionel e s p o r t d e e l n e m e r s , is s o d a ­ nige doelstel lin g nie v o ld o e n d e nie. d a a r w o rd vereis dat die d e e l n e m e r so gou as m o o n t li k tot d ie spel m o et te rugkeer. die psigologie se i m p a k van so 'n eis kan eg ter s o m s g r o t e r s k a d e aa n ri g as d ie insid en sie van die b e s e ri n g self. effe ktie we reh ab ili tasie k a n s o m s ’n ty d r o w e n d e p ro s es wees w a a r t y d e n s die d e e l n e m e r som s nie g e d u l d het o m voile fu nsionel e v e r m o e te h e r w i n nie. d a a r is gevalle in d ie vs a o p g e t e k e n w aar sp elers v o orge ge e het d at h u ll e ten voile herstel h e t , m a a r o n d e r s o e k e a a n g e d u i het dat fu n k s i o n e l e v e r m o e n o g nie ten voile h e rw i n is nie. d o e l g e rig t e post t ra u m a t i e s e re h a b ili ta s ie k a n in so m mi ge opsi g te h ie rd ie soor t van pro ble em o o r b r u g en d ie s p e le r in die spel te ru g ge plaas s o n d e r verlies aan fisieke verm oe . die w a a r d e v a n p o s t t r a u m a ti e s e fisieke re h ab ili tas ie le o p g e t e k e n in die su ks es se wat m e t s o d a n i g e p r o g r a m m e behaal is. die in t e ra k s i e tu s s e n d ie reha b il i t a s i e p ro g ra m e n die k o r r e k t e d ia g ­ nose van d ie b e s e ri n g e n / o f d ie ge sla ag dh eid van die c h i ru rg ie s e p r o s e d u r e ka n in ’n g ro o t m a te die suks es van fisieke re h ab ili tas ie bepaal . fi siek e re h ab ili tas ie w o rd s o m s ook ge b r u i k o m d ie g e s la a g d h e i d v an die oper asie in die her stel v an fu n k s i o n e l e v e r ­ m o e te b e o o rd eel. o n g e a g na w a ite r k an t van die skaal g e k y k w o r d , het n a ­ v o rs in g die w a a r d e v an finale fase fisieke rehab ili ta sie l a n k gel ed e reed s bev estig . ver d ik el al (1 967) en w oo el al. (1979) het a a n g e t o o n dat g e d u r e n d e s u b m a k s i m a l e iso k in et ies e w e e rs t a n d s in o e fe n i n g , v e r s t e r k in g van l ig am en te en te n d o n s k a n v o o r k o m . ter o n d e r s t e u n i n g h ie rv a n het z u k e r m a n et al. (1969) en t i p t o n et al. (1970) vroee ree ds b ev in d dat w e e r s t a n d s o e f e n m g die b r e e k k r a g en k r a g d r a v e r m o e van li­ g a m e n t e ka n v e rh o o g . s o d o e n d e ka n g e g r a d e e r d e p r o g r e s s i e w e w e e r s t a n d s o ef en inge va n s u b m a k s i m a l e tot maksi m a le inten site it as s t i m u l u s vir groei en v e r s t e r k in g van d ie l ig am en te d ie n. h i e ru it k an afgelei w o r d dat in gevalle m e t lig a m e n tl a k s i te i t , r e k o n s t r u k s i e en t e n d o n s k e u r i n g s , effe ktie we fu n k s i o ­ nele h erstel d e u r finale fase fisieke r e h a ­ bilitasie bew erk s te ll ig k a n w o rd . da vie s (1 9 8 5:2 2 4 -2 2 8 ) het a a n g e t o o n dat p e r s o n e met patella s u b l u k s a s i e na slegs 6 w ek e va n iso k in eti ese w e e rs t a n d sin o efe n in g ’n m e r k b a r e v e r b e t e r i n g in k ra g l e w e ri n g o n d e r v i n d het. in hie rd ie stu d ie is a a n g e t o o n dat a b n o r m a l i te it e in die k r a g l e w e r i n g s k u r w e , wat t ip e re n d van h ie r d ie p r o b l e e m is, m e t fisieke r e ­ habili tasie v e r w y d e r k an w o r d . die s tu d i e het o o k a a n g e t o o n dat v e r b e t e r ­ ing in d ie sta bilit ei t van die q u a d r i c e p s m e g a n i s m e en k r a g l e w e r i n g , in ’n g ro ot m a te k an k o m p e n s e e r vir d ie s u b ­ luksasie van die p at el la. o o k in d ie geval van c h o n d r o m a l a c i a pat el lae en patello fem o ra le p y n is g e v in d dat fisieke r e h a ­ bilitasie ’n eff ektie w e v e r m i n d e r i n g en selfs v e r d w v n i n g v an p y n k an teweeg b ri n g (d a v i e s , 1985:237). da vie s (1985) het o o k g ev in d dat p e r ­ so ne m e t a n t e r i o r k r u i s l i g a m e n t r e k o n ­ s tr u k s i e , m e t a a n v a n g v an p o s t t r a u m a tiese re h ab ili tas ie s te ed s soveel as 4 0 % verlies v an k r a g l e w e r i n g het. d o e l g e ­ ri gte fisieke r e h a b i li t a s ie k an h ie rd ie v e r s w a k k in g eg ter b i n n e e n k ele w eke verwyder. f is iek e re h a b i li t a s ie sal egte r nie net die pas ie nt se s p i e r k r a g va n die b e s e e rd e b ee n n o r m a l i s e e r n ie , m a a r oo k t e g e l y k e rt y d v e r s t e r k i n g van die ge r e k o n s t r u e e r d e l i g a m e n t laat pla asvin d . die w a a r d e va n p o s t t r a u m a ti e s e fisieke re h ab ili tas ie w o r d o o k in ’n on v a t te n d e o n d e r s o e k d e u r cilliers (1985) a a n g e d u i. in h ie rd ie n a v o rs in g me t o o rl o g s b e s e e rd e s is a a n g e t o o n d at selfs in ’n wy e s p e k t r u m van b es erin g s e n pa to lo g ie s/ o rt o pe diese t o e s t a n d e , finale fase fisieke reh abili ta sie o p ’n w y e ter rei n van w a a r d e k an wees. dit herstel nie net die f u n k sio n e le v e r m o e van die p as ie nt nie, m a a r lewer o o k ’n b y d r a e in die v e r h o g in g van die i n d i v id u se self beeld , selfv ertro u e en psigiese inge s te ld h eid ten opsi g te van s y /h aar situa sie. ter o p s o m m i n g ka n d ie g ed ag te van “ ’n b e t e r e i n d p r o d u k ” na fisieke r e h a b i l ­ itasie as k e r n g e d a g t e v o o r g e h o u w o rd . d e u r die res u lta te va n g e re h a b i li t e e rd e d e e l n e m e r s aan a n d e r b e s e e rd e sp ortl u i te to o n , sal die w a a r d e va n h ie rd ie be lan gr ike fase in die b e h a n d e l i n g van die p ers o o n inslag v in d. b ib l io g r a f ie 1. a p p e n l e n d u n c a n p w . 19b6. s t r e n g t h r e ­ l a t i o n s h i p o f t h e k n e e m u s c u l a t u r e : ef fe ct o f g r a v i t y a n d s p o r t . j o rth en sp o rts p hvs ther, 7/5: 2 3 2 2 3 5 . 2. c i l l i e r s j f 1985. d i e b y d r a e v a n g e p r o g r a m m e e r d e i n o e f e n i n g in d i e n a m e d i e s e f isi eke r e h a b i l i t a s i e v a n b e s e e r d e s ui t d i e mi l i te r e o p e r a s i o n e l e g e b i e d . geklassifiseerde p ro efskrif, p u v i r c h o , p o t c h e f s i r o o m . 3. d a v i e s g j . 1985. a c o m p e n d i u m o f i s ok i n e t i c s in c l i n i c a l u s a g e . 2 n d e d . w i s c o n s i n , u s a . 5 5 2 p . 4. h u n t e r s , c a i n t e e n h e n r y l 197 9. p r e ­ s e a s o n i s o k i n e t i c k n e e e v a l u a t i o n i n p r o ­ f e ss io n al f o o t b a l l a t h l e t e s . athletic training, w i n t e r , p . 2 0 5 2 0 6 . 5. n o b l e c . 198 0. p r e v e n t i o n o f r u g b y i n j u r i e s . s a j o u r n a l o f sp o rts m e d icin e . 9: 12-14. 6. r i c e s g . 1984. p r e p a r t i c i p a t i o n e v a l u a t i o n o f r e t u r n i n g h i g h s c h o o l a t h l e t e s ( a b s t r a c t ) . ai c d s c is p o r ts en e xercise, 16/2: 192. 7 s t a n i s h w d . 1984. o v e r u s e i n i u r i e s in a t h ­ let es: a p e r s p e c t i v e . m e d s e t sp o rts en e xe r­ cise, 16/1: 1-7 8. s t r y d o m g l . 1985. d i e v o o r b e r e i d i n g v a n d i e s p o r t m a n t e r v o o r k o m i n g v a n s p o r t b e s e r i n g s . voordrag: sponbescringsim po sium , p o t c h e f s i r o o m . 8 p . 9. t i p t o n c m . et al. 1970. i n f l u e n c e o f e x e r c i s e o n s t r e n g t h o f m e d i a l c o l l a t e r a l l i g a m e n t o f d o g s . a m e r'j p h y sio l. 2 18: 8 9 4 9 0 2 . 10. v e r d i c a . et al. 1967. t h e e ffe ct o f t r a i n i n g o n l h e t e n s i l e s t r e n g t h o f i s o l a t e d r a b b i t t e n ­ d o n s . s c a n d j p lus r econst s u rg , 1. 141 147. 11. w a t s o n a w s . 1981. f a c t o r s p r e d i s p o s i n g to s p o r t s m i u r y in s c h o o l b o v r u g b y p l a y e r s . j s p o r is m e d , 2 1 : 4 1 7 4 2 2 . 12. w o o s. l v . et al. 1979. l o n g t e r m e x e r c i s e e f f e c t s o n t h e b i o c h e m i c a l a n d s t r u c t u r a l p r o p e r t i e s o f s w i n e t e n d o n s . transactions o f the 25th a n n m eeting, o rth. research s o c, 4: 23. 13. z u c k e r m a n j . et al. 1969. e f f e c t s o f e x e r c i s e o n k n e e l i g a m e n t s e p a r a t i o n f o r c e i n r a t s . j a p p lp h y sio l, 2 6: 7 1 6 7 1 9 . 14 ----------------------------------------------------------s p o r t s m e d i c i n e vol5. n o i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) q o ---pan amor' 25 erdenc coaled tablet containing 25mg diclolenac sodium t l j rey no r/3 1'49 o o ---panamor' at 50 entenc coaled tahtet containing 50mg dciolenac sodium --------reg no ri3 1/50 panamor' 75 injection each 3m f ampoule contains 75mg diclofenac sooium with 4% v/v banzy alcohol as preservative reg no w/3 1/52 is your patient being held prisoner to pain and immobility? there is a release... diclofenac a non-stcroidal anti-inflammatory . relieves pain . reduces inflammat . restores mobility . reduces the cost o trauma therapy ‘*tv a v a ila b le now in. three panamor? ~ 2 5 tabijsy^y panam or**1 a t ^ g j m t e panamor® 7 5 in j e c t ^ m release from inflammatory pain gray indepenr ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports injuries an evaluation of hamstring/quadricep strength ratios in elite long distance runners and sprinters l d avim es and i levinrad abstract k eyw o rd s: h am string/quadriceps strength ratios, normative, endurance runners, sprinters, cybex the purpose o f this study was to investigate hamstring/quadricep strength ratios in long distance runners and sprinters. hamstring/quadriceps strength ratios were obtained in twenty five elite long distance runners and twenty one sprinters at a testing speed o f 60 degrees/sec on the cybex ii. hamstrings were found to be 62% and 59% o f quadriceps in sprinters and long distance runners respectively. sprinters generated significantly greater knee flexor and extensor muscle torque than long distance runners for both legs even when strength was expressed relative to body weight. n o significant difference in strength between the dominant and nondominant legs was observed in sprinters. dominant knee flexors were significantly stronger than nondominant flexors in long distance runners. the study established normative data on hamstring/quadriceps strength ratios in the two types o f running discipline. t he ratio may provide a guide for prophylactic measures athletes can follow for safe participation in sprinting or running. in tr o d u c t io n i s o kinet ic s t r e n g t h t es ti n g can be u s e d to id e ntify m u s c l e s t r e n g t h i m b a l a n c e o r w eak n ess. t h e flex o r/ e xten s o r s tr e n g t h b alan ce is i m p o r t a n t in th e s ta biliz atio n o f t h e k n e e a n d m a y b e a factor in k n e e joint i n ju ry s h o u l d th e rat io be a b n o r lee d avim es d epartm ent o f p h y s io th e r a p y 1 a n d physiology2 u niversity o fw itzua tersra n d m ed ica l school johannesburg iv a n l e vin ra d 104 h ig h la n ds n o r th m ed ica l centre h ighlands n o r th johannesburg mal. t h u s m u s c l e s o r join ts m a y be m o r e p r o n e to i n j u r y if th e ag o n is t a n d a n tag on is t differ signific an tly in s tr e n g t h . e s t a b l i s h m e n t o f n o r m a l k n e e flexor/exten sor rat ios m a y be a n eces s ­ ary p ro p h y l a c t i c m e a s u r e ag ai n st injury. it m a y b e p o ss ib le to id e ntify an a b n o r ­ mal ratio early a n d this ca n b e u sed as a w a r n i n g sign to p r e v e n t injury. h o w ­ ever, it is no t clear at this stage wh at c o n s ti tu te s a n o r m a l a n d a b n o r m a l ratio. i f re search is to b e d o n e on i d e n t i ­ fying a b n o r m a l ra tios t h e n it is essential to es tab li sh a n o r m a l ratio. in a d d i t i o n , in r e h a b i li t a t io n o f an i n ­ j u r e d k n e e , p ro g re s s is u s u a ll y assessed by a c o m p a r i s o n o f s t r e n g t h o f the i n ­ j u r e d k n e e w ith t h e n o n i n j u r e d c o n t r a ­ lateral k n ee. h o w e v e r, in bilateral kn ee inju ri es it is no t k n o w n at w h a t p o in t the p a t ie n t is r e h a b i li t a t e d a n d a c o m p a r i ­ son o f th e k n e e s t r e n g t h s will not allow a d e t e r m i n a t i o n o f re a s o n a b l e r e h a b i li ­ ta tio n goals. it is t h e re fo re i m p o r t a n t to k n o w w h a t n o r m a l rat ios a re befo re r e ­ t u r n i n g to s p o r ti n g activities. c a m p b e l l a n d g l e n n 3 c o n c l u d e d t h a t a t t e n ti o n s h o u l d b e d ir e c t e d to t h e h a m s t r i n g / q u a d r i c e p s t r e n g t h rat io in re h a b i l i ­ tat ion o f th e k n ee. g oslin g 13 et al c o n ­ t e n d e d tha t k n e e r e h a b i li t a t io n is not c o m p l e t e u n le s s ex ten sio n :f le x io n was 2 : 1. n o r m a t i v e data m a y d if fe r in p eo p le inv o lv ed in dif fe re n t s p o r ts since th e re are specific skills r e q u i r e d in d if ferent s p o r ts a n d specific t o r q u e str esses an at h le te is r e q u i r e d to e n d u r e . 10 t h e r e m a y be a m i n i m u m h a m s t r i n g / q u a d r i ­ cep s tr e n g t h rat io an a th le te s h o u l d ach iev e in o r d e r to safely p a r t ic ip a t e in a specific s p o r t. t h e r e f o r e it m a y be nec es sar y to test h a m s t r i n g / q u a d r i c e p s tr e n g t h rat ios in d if fe re n t sp o r ts . t h i s s t u d y inv es tigate s s t r e n g t h ra tios in r u n ­ ners. a rev ie w o f t h e lit e r a t u r e has i n d i ­ cat ed th a t no n o r m a t i v e data for h a m ­ s t r i n g / q u a d r i c e p s s t r e n g t h rat ios are av ailable for long d is tan ce r u n n e r s a n d 16 ---------------------------------------------------------s p o r t s m e d i c i n e vol 5. n o i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports injuries s printer s. t h e p u r p o s e o f this s t u d y was to establish n o r m a t i v e h a m s t r i n g / q u a d ­ riceps s t r e n g t h rati os in lo n g d is tan ce r u n n e rs a n d s p r in t e r s . in a d d i t i o n , the knee flexors a n d e x t e n s o rs o f lon g d i s ­ tance r u n n e r s a n d s p r i n t e r s will b e c o m ­ p ared . t h e d o m i n a n t leg s t r e n g t h will be c o m p a r e d w i th t h e n o n d o m i n a n t leg in each g r o u p o f su bjects. m e t h o d selection o f subjects t w e n ty five lo n g d is t a n c e r u n n e r s (m a ra t h o n r u n n e r s o r h a l f m a r a t h o n ru n n ers ) a n d t w e n ty t h r e e s p r i n t e r s ages 17-32 years s e rv e d as s u b j e c t s in the study. t h e pro to co l was p as sed by th e c o m ­ mittee for r e s e a r c h on h u m a n s u b ­ jects. testing d evice t h e c y b e x ii was u sed as th e testi n g d e ­ vice to d e t e r m i n e s t r e n g t h d e v e l o p e d by the lim b d u r i n g k n e e flexion a n d e x t e n ­ sion (c yb ex d i v i s i o n , l u m e x i n c . , bay shore, n . y . ) . t h e d y n a m o m e t e r was cal ibrate d a c c o r d i n g to the p r o c e d u r e suggested by the c y b e x m a n u fa c tu re r. t h e cy b ex a p p a r a t u s m e a s u r e s kn ee flexion a n d e x t e n si o n at a p re s e t sp eed . d u r i n g co n v e n ti o n a l exer ci se e n e r g y is mainl y d is s i p a te d w ith acc ele ra tio n s in the exercise. t h e c y b e x m e c h a n ic a ll y p re v en ts this d is s ip ati o n o f e n e r g y a n d conver ts it to a resisti ng force w h ic h is p ro p o r ti o n al to t h e m u s c u l a r force. experimental procedure g ravitational e ffec t torque (g e t ) t h e g ra v ita ti o n al effect t o r q u e is the torqu e re s u l ti n g fro m t h e effect o f the gravity on th e c o m b i n e d w e i g h t o f the leg a n d th e d y n a m o m e t e r a r m . g e t w as d e t e r m i n e d in o r d e r to as­ certain c o rre c tl y th e relative s t r e n g t h o f the an t a g o n i s ts in v er se ly affecte d by gravity. g e t in ftlbs was o b ta i n e d b y loc king the su bjects k n e e i n t o full ex ten sio n a n d the n i n s t r u c t in g h im to relax his q u a d r i ­ ceps m u s c le . t h i s was re p e a t e d again such tha t a c o n s is t e n t v al ue was o b ­ tained. test on the c ybex after adequate w arm up t h e test wa s p e r f o r m e d at 60 d e g re e s / sec to d e t e r m i n e s t r e n g t h o f t h e h a m ­ strings a n d q u a d r i c e p s as in d i v id u a l m u scles a n d as a ratio. analysis o f v ari ance tests w e r e u sed to c o m p a r e r u n n e r s w i th re sp ec t to age, m a ss , h a m s t r i n g / q u a d r i c e p s ratios a n d flexion a n d e x t e n si o n e x p re s s e d relat ive to b o d y w eig ht. analysis o f cov ari an ce tests w ere u s ed to c o m p e n s a t e for th e effect o f mass in flexion a n d ex ten sio n . d o m i ­ n a n c e was c o m p a r e d w ith n o n d o m i ­ n an ce by a p airw is e c o m p a r i s o n o f m e an s. a lin ea r re g res s io n an alysis was c o m p l e t e d for h a m s t r i n g a n d q u a d r i ­ ceps m u s c l e t o r q u e v ers u s total b o d y wei ght . p e a rs o n c o rr e la ti o n s w e re ca l­ cu lat ed on e ac h vari able. results physical c h a ra c te r is t ic s o f t h e su bjects are p r e s e n t e d in t ab le 1. t h e r e w ere sig­ nificant d iffe re n ces in w eig h t b e tw een s p rin t e rs a n d long d is t a n c e r u n n e r s . t h e m e a n s a n d s t a n d a r d d evia tio ns for p e a k h a m s t r i n g a n d q u a d r i c e p s t o r ­ q u e for left a n d rig ht legs ar e p r e s e n t e d in table 2. t h e q u a d r i c e p s possessed h ig h e r m e a n p e a k t o r q u e va lues th an t he h a m s t r i n g s in b o th g r o u p s o f s u b ­ jects. d iff ere n ces in h a m s t r i n g a n d q u a d r i c e p m e a n t o r q u e b e t w e e n s p r i n t ­ ers a n d long d is t a n c e r u n n e r s w e r e a n a ­ lysed. s p r i n t e r s were f o u n d to p r o d u c e sign ificantly g r e a t e r m e a n peak h a m ­ s tr in g a n d q u a d r i c e p s t o r q u e t h a n long d is tan ce r u n n e r s . peak flexor a n d e x t e n ­ sor t o r q u e e x p re s s e d relativ e to bo dy w ei ght was s ig n if ic an tly g r e a t e r in s p rin t e rs th a n in long d is t a n c e r u n n e r s (table 2). table 3 s h o w s the m e a n s a n d s ta n ­ d a rd d e v ia ti o n s for t h e h a m s t r i n g / q u a d ­ ricep s s t r e n g t h rat ios in b o th g ro u p s . t h e rig h t h a m s t r i n g / q u a d r i c e p rat io did not differ signific an tly in th e two g ro u p s . t h e left h a m s t r i n g / q u a d r i c e p ratio wa s significantly h i g h e r in s p r i n t ­ ers t h a n in lon g d is t a n c e r u n n e r s (p < 0,05). t h e m e a n s a n d s t a n d a r d d e v ia ti o n s o f p eak t o r q u e v al ues for the d o m i n a n t a n d n o n d o m i n a n t q u a d r i c e p s a n d h a m table 1: m e a n s a n d s t a n d a r d d ev ia ti o n s for ag e, w eig h t a n d p e r f o r m a n c e in long d is t a n c e r u n n e r s a n d s p rin t e rs . age (years) weight (kg) best performance long 26,24±0.70 66,90+10 42km : 158 min distance 21km: 74 min runners sprinters 22,00±0,90 70,82± 1,84 200m :21,8±0,15sec 100m: 10,7±0,05sec table 2: m e a n s ( ± s d ) o f p e a k t o r q u e (ft lbs) a n d p e a k t o r q u e / k g b o d y w eig h t for q u a d r i c e p s a n d h a m s t r i n g s o f ri g h t a n d left legs group muscle group peak torque (ftlbs) right leg left leg peak torque/kg (ft lbs/kg) right leg left leg sprinters (n = 21) long dist runners (n = 25 quadriceps hamstrings quadriceps hamstrings 170,24±7.10 106.33±4.50 139.64±3.26 85.4 ±2.26 169.71 ±6.74 105.57±4.98 140.12±3.82 80.00±2.81 2.4±0.07 1.49+0.04 2.08±0.05 1.28±0.03 2.40±0.08 1,48±0.05 2.11 ±0.06 120±0.04 s p o r t g e n e e s k u n d e v o l 5 . n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports physiology strings m u s c l e g r o u p s ar e p r e s e n t e d in table 4. n o significan t dif fe re nce s in p e a k t o r q u e o f the h a m s t r i n g s a n d q u a ­ d ri c e p s a n d t h e re fo re in s tr e n g t h rat ios (table 5) b e t w e e n t h e d o m i n a n t a n d n o n d o m i n a n t leg for s p r in t e r s were fo u n d . in lo n g d is t a n c e r u n n e r s , the d o m i n a n t h a m s t r i n g s w ere significantly s tr o n g e r t h a n t h e n o n d o m i n a n t h a m ­ str ings b u t t h e q u a d r i c e p s did not differ significantly. t h i s r es u lte d in t h e d o m i ­ n a n t leg c re a ti n g a significantly h ig h e r fl ex or/e xten sor rat io, c o m p a r e d w ith t he no n d o m i n a n t leg (table 5) in lon g dis tan ce r u n n e r s . t h e re la t io n s h ip o f total b o d y w eig ht to rig ht a n d left q u a d r i c e p s m u s c l e t o r ­ q u e in s p r in t e r s w as sign ificant (r = 0,7 7 an d r = 0 .6 0 re sp ec tively ). t h e r e was a significant co rre l a t i o n b e t w e e n rig ht a n d left h a m s t r i n g t o r q u e a n d bo dy we ig ht in s p r in t e r s (r = 0.7 5 ; r = 0.60). in lon g d is tan ce r u n n e r s , a significan t co rrelation o f b o d y w eig h t a n d p ea k h a m s t r i n g m u s cle t o r q u e on the rig ht leg was fo u n d (r = 0.63). n o r o t h e r sig­ nificant c o rre la tio n s o f m u s c l e t o r q u e w ith b o d y w eig h t w e re f o u n d in long d is tan ce r u n n e r s . h a m s t r i n g / q u a d r i c e p s m u scl e s tr e n g t h rati os w ere not significant co r­ relat ed w ith b o d y weig ht in eithe r g r o u p s o f r u n n e r s (p < 0.05). d isc u ssio n t h e at h le te s u sed in this s t u d y were tested d u r i n g the c o m p e t i ti v e p e ri o d of the r u n n i n g season. t h e y w e re well t ra ine d a n d in ex cel lent p h ys ic al c o n ­ d iti on wi th no k n e e c o n d it i o n o r thigh m u s cle s tr ain for at least a 3 m o n t h pe ri o d p r i o r to the study. t h e i r i n ju ry h is to ry in d ic a te d a low in c id e n c e o f i n ­ ju ry o v er th e past y ear a n d no p a r t ic i ­ p a n ts h ad a n y m u s c l e i m b a l a n c e p r e d i s ­ posi n g t h e m to injury. isokinetic strength n o significan t age re lat ed d iffe re n ces in isokin etic s t r e n g t h w ere f o u n d fro m an analysis o f v arian ce test in e i t h e r g r o u p s o f su bjects. t h i s is in c o n tr a s t to o t h e r inv es tiga to rs w h o hav e f o u n d significant increases in h a m s t r i n g a n d q u a d r i c e p s m u s cle s t r e n g t h w i th in c re as in g ag e _ 10.21.23.24.29 h o w ev er, this m a y have b ee n the re s u lt o f d if fe re n t age ran ges. m u r r a y (26), for e x a m p l e , fo u n d y o u n g e r m e n (age 20-35 years) to be sig ­ nificantly s tr o n g e r th a n o l d e r m e n (45 65 y ea rs ), however, q u a d r i c e p s m u s cle s tr e n g t h was as sesse d isometrically, no t isokinetically. s p r i n t e r s h ad signific an tly s tr o n g e r q u a d r i c e p s a n d h a m s t r i n g s t h a n long dis tan ce r u n n e r s . t h e m e a n p e a k t o r ­ q u e values o f t h e q u a d r i c e p s a n d h a m ­ str in g s in lon g d is t a n c e r u n n e r s (13 9 .6 4 ± 3.26 a n d 85.4 ± 2 .2 6 ftlbs o r 189.35 ± 4.4 2 a n d 115.80 ± 3.0 7 n m ) is s im i ­ lar to tha t f o u n d by m o r r i s (25) el a l in d is tan ce r u n n e r s te sted at the same s pee d (i.e. 132.6 ± 16.59 a n d 86.7 ± 12.91 ftlbs o r 179.81 ± 2 2 .5 0 a n d 117.57 ± 17.51 n m ) . gi lli am 10 el al r e ­ p o rte d sim ila r q u a d r i c e p s a n d h a m ­ str in g s t o r q u e va lues in football lin e m e n to tho se va lues o b ta i n e d b y s p r i n t e r s in this study. t h e dif fe re n ce in s tr e n g t h o b s e rv e d in s p r i n t e r s a n d long dis tan ce r u n n e r s te sted at the s am e s p e e d m a y be rel at ed to m u s c l e fibre co m p o s i ti o n . s tu d ie s have s h o w n a p r e d o m i n a n c e o f slow tw it ch m u s c l e fibres o f e n d u r a n c e a thle tes a n d a h ig h p r o p o r t i o n o f fast table 3: m e a n s ( ± s d ) o f the h a m s t r i n g / q u a d r i c e p s rat io for left a n d rig h t legs group ratio of mean right leg peak torque left leg sprinters 62.91 ± 1.68 62.14 ± 1.68 long dist 61.32 ± 1.37 57.28 ± 1.42 runners table 4: m e a n s ( ± s d ) o f t h e d o m i n a n t a n d n o n d o m i n a n t h a m s t r i n g a n d q u a d r ic e p s group muscle peak torque (ft lbs) group dominant leg non dominant leg sprinters quadriceps 171.33+6.78 163.62±7.05 hamstrings 107.33±4.43 104.5715.00 long dist quadriceps 140,32±3.44 139.44± 3.66runners hamstrings 85.56±2.32 79.80±2.71 table 5: m e a n s (± sd ) o f the h a m s t r i n g / q u a d r i c e p s ratio for the d o m i n a n t a n d n o n d o m i n a n t legs group ratio of peak torque (hamstring/quadriceps) dominant leg non dominant leg sprinters 62.99 ± 1.66 62.05 ± 1.70 long dist 61.16 ± 1.34 5 7 . 4 4 + 1.47runners 8 6 % o f s p r i n t e r s a r e r i g h t l eg d o m i n a n t , 1 4 % a r e lef t l e g d o m i n a n t , 8 4 % o f l o n g d i s t a n c e r u n n e r s a r e r i g h t leg d o m i n a n t , 1 6 % a r e left l e g d o m i n a n t . s p o r t s m e d i c i n e vol 5. n o i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports physiology twitch m u s c l e fibres in s p r in t a t h ­ letes.561:34 fa st tw it ch fibres are i m ­ port ant for force o u t p u t d u r i n g fast c o n ­ tractions w h ic h are r e q u i r e d for s p r i n t i n g . 34 h o w ev er, t h o r s t e n s o n 34 et al fo und t h a t h ig h t o r q u e values w ere a t ­ tained by track at h le te s w i th a low p r o ­ p o rt io n o f fast t w it c h fi b re s, a n d thu s there is no co n clusiv e e v i d e n c e that p e r ­ fo rm an ce can be p r e d i c te d on th e d i s t r i ­ b u ti o n o f fibres in the m u s cles . hamstring/quadriceps strength ratios values o b ta i n e d for h a m s t r i n g / q u a d r i ­ ceps s tr e n g t h ratios have b e e n re p o rt e d in the l i t e r a t u r e . 27 t h e rat ios o b t a i n e d in this s tu d y ag ree w i th t ho s e r e p o r t e d by o th er a u t h o r s . h o l m e s ' 2 et al fo u n d flexor/e xten so r rat ios o f 0 .5 8 in male high school s tu d e n t s for t h e d o m i n a n t leg. in a s tu d y o f h ig h sch ool football pla ye rs , ratios o f 0 .5 6 at 54 d eg re es /sec were o b t a i n e d . 29 m o r r i s 25 et al fo u n d h a m s t r i n g / q u a d r i c e p s s t r e n g t h rat ios in collegiate m i d d l e d is tan ce r u n n e r s to be similar at low sp eed s (0. 63 at 30 d e ­ grees/sec a n d 0.65 at 60 d egre es /s ec ). s c u d d e r 31 r e p o r t e d h a m s t r i n g s to be 60% o f q u a d r i c e p s irre s p e c t iv e o f the speed o f testin g. it has b e e n su gg es ted that k e e p i n g the t o r q u e o u t p u t o f the h a m s t r i n g s 6 0 % o f the q u a d r i c e p s m i n i ­ mizes the e x t r a o r d i n a r y a m o u n t s o f stress on the k n ee. g osli n a n d c h a r te r is 13 su gg es ted a d ev ia ti o n in the h a m s t r i n g / q u a d r i c e p s s t r e n g t h ratio fro m 1 : 2.25 w o u ld in c re as e the risk o f injury. h o w ev er, the s t u d y i n c lu d e d male a n d fem ale n o n ath le tes. s tu d ie s w h ic h hav e s h o w n a dif fe re n t s tr e n g t h rat io h av e in v o lv ed d if ferent p o p u l a t io n s . w y a t t 35 r e p o r t e d h ig h e r ratios for m e n th a n for w o m e n te sted at 60 d eg re es /sec . e a rl ie r s tu d i e s r e p o r t e d ratios o f 0 . 5 , h o w e v e r t h e s u b jects o f s uch s tu d i e s did n o t inv olv e a t h l e t e s . 17,22 g i ll i a m 10 et al f o u n d football pla yers to have a flex o r/ e xten so r s t r e n g t h ratio o f 0 . 6 . t h u s it w o u ld a p p e a r t h a t flexor/ ex ten so r s t r e n g t h rat ios m a y be specific for dif fe re n t s p o r ts o r for d if fe re n t lev­ els o f skill r e q u i r e d in s p o r t. rati o s o f 0.62 for s p r in t e r s a n d 0 .5 9 for lon g d i s ­ tance r u n n e r s m a y in d icate a n o r m a l fl exor/exten sor b a la n c e for t h e se a t h ­ letes. f u t u r e re s e a r c h s h o u l d be c o n ­ d u c te d on at h le te s in dif fe re n t s p orts . body weight and peak m uscle torque output a re l a t io n s h ip b e t w e e n total b o d y wei ght a n d p e a k q u a d r i c e p s a n d h a m ­ str in g m u s c l e t o r q u e o u t p u t has b ee n p rev iou s ly d e m o n s t r a t e d . 10’29-118 t h e data fro m the p r e s e n t s t u d y also p r o ­ d u c e d signific an t co rre l a t i o n s b e t w e e n peak q u a d r i c e p s a n d h a m s t r i n g s tr e n g t h an d b o d y w eig h t for s p r i n t e r s a n d b e ­ tw een rig ht h a m s t r i n g s for lon g d is tan ce ru n n e r s . w h e n t o r q u e values w ere e x ­ p re s s e d relat ive to b o d y w e i g h t , s p r i n t ­ ers s h o w e d significantly h ig h e r peak q u a d r i c e p s a n d h a m s t r i n g s t r e n g t h values t h a n long d is t a n c e r u n n e r s . t h i s finding c o n t r a d i c t s t h a t o f h o u s h 19 w h o fo u n d little d if fe re n ces in s t r e n g t h b e ­ tw ee n fem ale track a n d field at h le te s w h e n flexor a n d e x t e n s o r t o r q u e was ex ­ p re s s ed relat ive to b o d y w eig ht. s i m i ­ larly no d if fe re n ce in s t r e n g t h b e t w e e n m a le a n d fem al e al p in e sk ie rs was fo u n d w h e n s t r e n g t h was e x p r e s s e d relat ive to lean b o d y w e i g h t . 15 t h e dif fe re n ces in s t r e n g t h b etw een the tw o g r o u p s o f r u n n e r s , h av in g s ta n ­ d a r d i z e d s t r e n g t h rel at ive to b o d y w e i g h t , m a y b e d u e to fa ct o rs o t h e r th a n wei ght d if fe re n ces s u c h as d if fe re n ce s in trainin g . w h e r e a s s p r i n t e r s e m p h a s i z e s t r e n g t h , s p e e d a n d p o w e r t ra i n i n g , long d is tan ce r u n n e r s c o n c e n t r a t e m o re on e n d u r a n c e t r a i n i n g w i th o n ly som e s t r e n g t h tra i n i n g . in a d d i t i o n , a train in g h is to ry o b ta i n e d fro m t h e r u n n e r s i n d i ­ cat ed th a t 8 6 % o f s p r i n t e r s p art ic ip a t e d in wei g ht tra i n i n g 2-3 t im e s a w eek w h ereas on ly 2 0 % o f long d is tan ce r u n ­ n ers too k p art in w eig h t tra i n i n g . t h u s ap art fro m the d iffe ri n g t r a i n i n g re g im es in the two t yp es o f a t h le te s , a s p rin t e rs t h u s p a r t ic ip a t e d in isoto nic s tr e n g t h tra in in g w h ic h re s u l ts in m u s c l e h y p e r ­ trophy. ----------------------------------------------------------------19s p o r t g e n e e s k u n d e vol 5. n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports physiology dominant and n on dominant leg strength t h e long d is t a n c e r u n n e r s d o m i n a n t a n d n o n d o m i n a n t h a m s t r i n g m u s c l e s tr e n g t h d if fered s ig n if ic an tly r e s u lti n g in d is s i m i l a r s t r e n g t h ratios . a l th o u g h n o d if fe re n ce b e t w e e n t h e d o m i n a n t a n d n o n d o m i n a n t q u a d r i c e p s o r h a m s t r i n g m u s c l e s t r e n g t h was f o u n d in s p r i n t e r s , st aff ord 32 et a l f o u n d d if fe re n ces in q u a d r i c e p s m u s c l e s t r e n g t h in football pla yers w h o h a v e s im i la r s t r e n g t h to the s p r i n t i n g p o p u l a t io n . a l t h o u g h the p r e s e n t s t u d y d id no t find t h is , q u a d r i ­ ceps m a y pla y a m o r e i m p o r t a n t ro le in the tra i n i n g activiti es o f s p r i n t i n g r e ­ lated s p o r ts w h e re a s t h e h a m s t r i n g s m a y play a m o r e i m p o r t a n t ro le in lon g d i s ­ t an ce r u n n i n g . it m a y b e s u g g es ted tha t m o r e e m p h a s i s s h o u l d be g iv en o n c o n ­ d it i o n i n g the n o n d o m i n a n t h a m s t r i n g s in long d is t a n c e r u n n e r s , however, th e re is no c o n clus iv e e v i d e n c e o f this. t h e re su lts o b t a i n e d in a c o m p a r is o n o f left a n d ri g h t legs a n d o f d o m i n a n t a n d n o n d o m i n a n t legs i n d icate the left h a m s t r i n g s a n d n o n d o m i n a n t h a m ­ str in g s o f lo n g d is t a n c e r u n n e r s to be sign ificantly w e a k e r t h a n th e rig ht a n d d o m i n a n t h a m s t r i n g s . t h e s im ila r it y in t hese re su lts is p r o b a b l y t h e result o f t h e re b eing an 8 6 % ri g h t leg d o m i n a n c e in long d is t a n c e r u n n e r s . conclusions t h i s s t u d y d e m o n s t r a t e d th e following: • h a m s t r i n g s are a p p r o x i m a t e l y 6 0 % o f q u a d r i c e p s t o r q u e at a s p e e d o f 60 d eg re es /s ec in r u n n e r s . • significant d iffe re n ces in q u a d r i c e p s a n d h a m s t r i n g s m u s c l e s t r e n g t h b e ­ tw ee n s p r i n t e r s a n d lon g d is t a n c e ru n n e r s . • significant c o rre l a t i o n b e t w e e n b o d y we ig ht a n d p e a k q u a d r i c e p s a n d h a m s t r i n g m u s c l e t o r q u e in s p r i n t ­ ers. • significa nt d if feren ces in d o m i n a n t a n d n o n d o m i n a n t q u a d r i c e p s a n d h a m s t r i n g m u s c l e s t r e n g t h in long d is t a n c e r u n n e r s b u t n o t in s p r i n t ­ ers. • n o significant age related effect on pe a k m u s c u l a r t o r q u e . r e f e r e n c e s 1. a g r e j c : h a m s t r i n g i n j u r i e s . p r o p o s e d ae t i o l o gi ca l f a c t o r s , p r e v e n t i o n a n d t r e a t m e n t . sp orts m edicine, 2: p p 21 3 3 , 1985. 2. a n i a n s s o n a , g r i m b y g , r u n d g r e n a: i s o ­ m e t r i c a n d i s o k i n e t i c q u a d r i c e p s m u s c l e s t r e n g t h in 7 0 y e a r o l d m e n a n d w o m e n . s c a n d j r e h a b m e d , 12: p p 1 6 1 1 6 8 , 1980. 3. c a m p b e l l d e , g l e n n w : r e h a b i l i t a t i o n o f k n e e f l e x o r a n d k n e e e x t e n s o r m u s c l e s t r e n g t h i n p a t i e n t s w i t h m e n i s e c i o m i e s , li­ g a m e n t o u s r e p a i r s a n d c h o n d i r o m a l a c i d . p hysical t h e ra p y ,6 2 : p p 10 -1 5, j a n 1982. 4. c o n t a i n s r , w i l l i a m s a k : i s o k i n e t i c q u 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ilita tio n , 5 6: p p 1 5 2 1 5 5 , a p r i l 1975. 29. p a r k e r m g , r u h l i n g r o , h o l t d , b a u m a n e , d r a y n a m : d e s c r i p t i v e a n a l y s i s o f q u a d ­ r i c e p s a n d h a m s t r i n g s m u s c l e t o r q u e in h i g h s c h o o l f o o t b a l l p l a y e r s . j o u r n a l o f o r­ thopaedic a n d sp orts p hysica l therap y, 5: p p 2 6 , 1 9 8 3 . 3 0 r i c h a r d s c l : d y n a m i c s t r e n g t h c h a r a c t e r i s ­ ti cs d u r i n g i s o k i n e t i c k n e e m o v e m e n t s in h e a l t h y w o m e n . physical therap y, 61: p p 6 8 7 3 , 1 9 8 0 . 31. s c u d d e r g n : t o r q u e c u r v e s p r o d u c e d at t h e k n e e d u r i n g i s o m e t r i c i s o k i n e t i c e x e r c i s e s . p hysical t h erap y, 6 1 : p p 6 8 7 3 , 1980. 32. s t a f f o r d m g , g r a n d wa: h a m s t r i n g / q u a d ­ r i c e p s r a i i o s in c o l l e g e f o o t b a l l p l a y e r s : a h i g h v e l o c i t y e v a l u a t i o n . a m erican j o u rn a l o f sp orts m e dicine, 12: p p 2 0 9 2 1 1 . m a y 1984. 33. t h i s t l e h g : i s o k i n e t i c c o n t r a c t i o n : a n e w c o n c e p t o f r e s i s t i v e e x e r c i s e . a rchives o f p hysica l m edicine a n d r eh a b ilita tio n , 48: p p 2 7 9 2 8 2 , j u n e 1967. 34. t h o r s i e n s s o n a , l a r s s o n l , t e s c h p , k a r l s s o n j: m u s c l e s t r e n g t h a n d f i b r e c o m p o ­ s i t i o n in a t h l e t e s a n d s e d e n t a r y m e n . m edicine a n d science in sp o rts, 9: p p 2 6 3 0 , 1977. 35. w y a t l m p : c o m p a r i s o n o f q u a d r i c e p s a n d h a m s t r i n g s t o r q u e v a l u e s d u r i n g i s o k i n e t i c e x e r c i s e . p h ysica l therapy: p 9 3 2 , a b s t r a c t . 20 ----------------------------------------------------------s p o r t s m e d i c i n e vol s. n o i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) will give yen ŝ swl mofc freedom to walk, jump, run and work 15amps south african journal of sports medicine sportgeneeskunde j o u r n a l o f t h e s.a. s p o r t s m e d i c i n e a ss oc i a t i o n t y d s k r i f van d i e s.a. s p or t ge n e e sk u n de v e r e ni g i ng v o l l ' m e s n u m b e r 2 may 1990 e ditor in c hief: d r c noble m b b c h , f c s 's a ) a s so c ia te editors: p ro f t n o a k es. m b c h b , m d d r d ozvievan v e ld c n m b c h b (s ie u )m p ra x m e d (p retoria i a d visory board: medicine: d r i cohen m b c h b , d .o b s t, r c o c o rt h o p a e d i c traumatology: d r p f ir e r b s c (e n g ) . m b bc h < w in ), m m e d (o n h o ) < wits) brig e hugo m b c h b , m m e d (c h it) orth opa edi cs: d r j c usdin m b b c h , f r c s (edin) cardiology: col d p m yburgh s m m b chb f a c c physical education: p ro f hannes botha d p h il i p hys ed) gynaecology: d r j ack a dno m b bch (w its) , m d (m ed), d ip o & g (w its) sa s g v s a s m a contents editorial comment causation o f injury ................................................. 3 preventative sports medicine altitude fails to increase susceptibility o f ultramarathon runners to post-race upper respiratory tract infections .................................... 4 rugby injuries rugby injuries o f the cervical spine and spinal cord — has the situation improved? ......... 9 sport injuries a survey o f all sport injuries .................................. 16 sports medicine physical examination o f the ankle and the foot 20 p u b l i s h e d by t h e s o u t h a f r ic a n s p o r t s m e d i c i n e a s s o c i a t io n h a t f i e l d f o r u m w e s t 1067 a r c a d i a s t r e e t h a t f i e l d p r e t o r i a . 00 8 3 p icturei courtesy o f p hotofilejim age b o n k t h e lo tir n a l o f ih e sa s p o m m e d ic in e a s s o c ia tio n is p u b lis h e d b y m c d p h a r m p u b lic a tio n s . 3 rd f lo o r n o o d h u lp lig a c e n tr e . 20 4 b h f v e rw o e rd d r iv e . r a n d b u r g 21 9 4 tel ( 0 1 1 j 7 8 7 -4 9 8 1 /9 t h e v iew s e x p r e s s e d in th is p u b lic a tio n a r e i h o s c o f th e a u th o r s a n d n o t n e c e s s a r ily th o s e o f th e p u b lis h e rs p rim e d b v t h e n a t a l w itn ess p rin t in g m d p u b lish in g c o m p jin ( p i v ) ltd ------------------------------------- 1 s p o r t g e n e e s k u n d e v o l 5. n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial there is a popular belief in the medical world today that a fatigued individual is more susceptible to disease than a non­ fatigued individual. from the clinical perspective, the effect of exercise on the immune system remains an enigma. that exercise has both immunostimulatory and immunosuppressive effects has been acknowledged for at least the last cen­ tury. over the last decade in particular, substantial evi­ dence from both laboratory-based investigations into specific aspects of immune functioning and epidemiolog­ ical studies of athletic populations supports this dualis tic relationship. athletes, coaches and sports doctors believe, with some justification, that sportspeople are more suscepti­ ble to certain illnesses during intense training and major competition. this is obviously a problem both in terms of their ability to compete, but there are also long term effects on training and health to consider. somewhat paradoxically, there is the common perception that those who exercise regularly are less susceptible to certain ill­ nesses, such as the common cold. while neither of these observations has been rigor­ ously assessed at an epidemiological level, the evidence would point to a dual effect o f exercise: intense exercise increases illness susceptibility while moderate exercise does the opposite. nieman2 has depicted this relation­ ship as a ‘j ” shaped curve. moderate regular exercise can reduce urti risk to below that of sedentary7 popula­ tion. however, beyond a point specific to each individual, the risk o f infection rises exponentially with an increase in exercise frequency, duration and intensity. the exact mechanisms of this immunosuppression are far from understood. the human immune system is highly complex and precisely ordered. it comprises cells, hormones and soluble immunomodulators that inhabit the bone, marrow, lymphoid tissues and ducts and peripheral circulation. because o f the number and com­ plexity of its interactions with other body systems, it is almost impossible to delineate, isolate or ascribe a spe­ cific function to any single pathway or mechanism. moreover, although significant exercise-induced immune alterations can be demonstrated in in vivo assay systems, there are presently no in vitro studies to c o n f i r m that these changes are biologically meaningful. nevertheless, highly trained and competitive athletes in a variety of sport disciplines, do appear to be at risk of developing an infection, particularly those of the upper respiratory tract (urtis). edith peters, author o f two papers in this edition, was the first south african researcher together with (eric bateman) to attempt to quantify rates of post-race illness in ultramarathon run­ ners/’ they confirmed that those athletes who ran the faster times, and trained the highest mileages were more likely than the slower, less well trained runners and the sedentary control subjects to develop urtis. subsequent studies on comrades runners have not entirely supported the ides that it is the more competi­ tive athlete who is more likely to develop post-race urti. ms peters reviews both her own work and that of other exercise immunologists in this publication. ever since linus pauling published his treatise on vit­ amin c and the common cold, this anti-oxidant has enjoyed good press. however, for once there is some fact behind the hype. peters and her colleagues at wits have shown that vitamin c supplementation, even more so than the other anti-oxidants (beta-carotene, \itamin e), oppenheimer and spaeth, 192 2 1 reduced the incidence of urtis in ultradistance nmners in the two week period after the comrades marathon. interest in the immune response to exercise has arisen for reasons other than those related to sports. one is the possible clinical implications. for example, could exercise play a role in the prevention and treatment of certain illnesses such as cancer and acquired immunod­ eficiency syndrome (aids) ? epidemiological evidence certainly suggests an association between regular physi­ cal activity and a lower incidence of certain cancers. animal studies have shown exercise training to enhance resistance to experimentally induced tumour growth. exercise is currently used as an adjunctive therapy to counteract die physically debilitating effects of the illness and treatment, and to improve (lie patients’ physical and psychological state. however, as the immune system plays a fundamental role in the progression of cancer and aids, the interactive effect of exercise on the immune system could itself prove to be therapeutically useful. although there is only one documented case o f h iv transmission as a result of participation in contact sport, athletes engaging in high risk behaviour are at the same risk of infection as non-sports persons. this means that the hiv epidemic will eventually affect physically active people. dr martin schwellnus discusses the effect hiv disease has on the ability to perform exercise, and what role exercise has on disease progression. despite a lack of epidemiological data from which to calculate the risk of h iv transmission during sports participation, dr schwellnus addresses the concerns of sports administra­ tors and participants with regard to this emotive subject. in reading these reviews it may occur to you that in trying to quantify and explain the effect that exercise has on immune functioning, scientists have overlooked a fun­ damental factor: the mind. although the concept of psy choneuroimmunology, (the interaction between the neu­ roendocrine and immune systems) is alluded to in the more recent studies, there is as yet no data to back up the theory'. exercise may be immunostimulatory7 because it reduces negative affective states, increases the release of endogenous opiates and reduces hpac activation. on the contrary, hard training and competition is immuno­ suppressive, because it serv es as an additional stressor to an already overloaded system. thus the sportsperson who is most likely to develop a urti is not the elite athlete w hose entire lifestyle and infrastructure is geared around his or her training. it is the individual who, on top of professional, domestic and social responsibilities, attempts to withstand the same training load as the top class athlete. dealing with their urti’s is going to require more than just judicious doses of vitamin c. references 1. oppenheimer eh, spaeth ra. the relation between fatigue and the susceptibility o f rats towards a toxin and an infection. a m j hygiene 1922;2:51-66. 2. nieman dc. exercise, upper respiratory tract infection and the immune system. med sci sports exer 1994;26:128-139. 3. peters em, bateman ed. respiratory tract infections: an epi­ demiological survey. s afr med j 1983;64:582-584. dr lindsay weight sports medicine march 1996 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) • for muscular pain • effective pain relief • site specific • non-staining • non-greasy reparil-gel relieves m uscular pain. • t ' t . madaus pharmaceuticals (pty) l t d “ f y i * 5-5 reg. no.: 77/00174/07 2nd road (cnr 16th road), randjespark, midrand 1685 hi] r epa ril-g e l 100 g contains: aescin 1,0 g; diethylamine salicylate 5,0 g. reg. no. g/13.9/2367 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m i : s o r m a f r k a x .k h r x a t , o r sports medicine volume 3__________ number 1_______ march 1996 e d itor prof td noakes dr mp schwellnus editorial board dr m e maolla dr p de jager dr j skowno dr p schwartz p rofr stretch dr c de ridder prof b c andrews dr e \v dermun mr r h farman prof m mars dr c a noble international advisory boar< lyle j micheli associate clinical professor i oithopaedic surgery boston, usa chester r kyle research director, sports equipment research associi california, usa p rof iic wildor hollmann president des deutschen sport iirztebimdes koln, west gcnnany howard j green professor, department of kinesiology ontario, canada george a brooks professor, department of physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke associate professor, biology department, university of colorado colorado. usa graham n smith physiologist glasgow, scotland the views expressed in individual articles are the personal view's of the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent of the publishers. 1 [>f itcs contents editorial l weight exercise and the immune system: a review l weight exercise and upper respiratory tract infections: a review e m peters iiiv infection in sport: a review of current issues m p schwellnus vit c as effective as combinations of anti-oxidant nutrients in reducing symptoms of upper respiratory tract infection in ultramarathon runners e m peters et al a social cognitive perspective on promotive and preventive health behaviour in post apartheid south africa i miller 9 16 23 29 the editor the south african journal of sports medicine po box 115, newlands 7725 production andrew thomas publishing glenbarr publishers cc private bag x14 parklaiids 2196 tel: ( oi l ) 442-9759 fax: ( oi l ) 880-7898 advertising marike de waal/andrew thomas reproduction output reproductions printing horlors cover sponsored by ciba-geigv sports medicine march 1996 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) exercise and the immune system: a review dr l w eig h t phd (uct) exactly how and why the immune system is challenged by exercise has been the subject of a concerted research effort over the last decade. what has emerged is a highly inconsistent puzzle, because of the extreme com­ plexity of the immune system and the barely quantifi­ able factors that influence it. further disparity is caused by the large variation in the age, gender and fit­ ness levels of the subjects, the extent or lack o f training, the duration and type o f exercise protocol and the tim ­ ing and frequency o f sampling. h ost defence parame­ ters measured in these studies range from simple determination of leukocyte counts to sophisticated eval­ uations of lymphocyte subsets and functions. large variations in the reliability of both in vivo and in vit ro assay techniques further compromise die reliability of studies in this field.1 although diere are few data on the effects of exercise 0 1 1 die immune system as a whole, there is a great deal of information on the influence it has on individual com­ ponents thereof. these studies form the basis o f diis review. exercise and leukocytes perhaps the best documented effect of exercise on die host defence system is an acute and immediate leuko cytosis, the magnitude of which is directly related to the intensity and duration o f work, and inversely pro­ portional to fitness level (for review, see mccarthy and dale2). the increase in leukocyte number, which can be up to four times the resting level, is predominantly due to increases in neutrophil and, to a lesser extent, lym­ phocyte counts, although monocyte numbers also increase. at die end of exercise lasting up to 3 0 minutes, the leukocyte count usually falls to normal levels within 103 0 minutes. lymphocyte counts drop 3 0-50% below pre-exercise levels, remaining low for 3 -6 hours. eosinophils also vacate the blood in large numbers while basophils tire largely unaffected:' after sustained exercise lasting 2 -3 hours, leukocyte counts may still be elevated for up to 2 4 hours. during very prolonged exercise (1 6 -2 4 hours), baseline levels may be reached even before the end o f exercise.4 moderate intensity7 exercise induces a much less pronounced leukocytosis, lymphocytosis, neutrophilia and lymphocytopenia.'" there appears to be no effect of training on resting leukocyte numbers, with virtually all papers reporting clinically normal values.2 some investigators have correspondence: dr lindsay weight dept physiology uct medical shool observatory 7925 tel: (021) 406-6400 fax: (021) 477-669 weight@ .physio .uct. ac. za reported that training blunts the leukocytosis o f exer­ cise while others have not.7-8 leukocyte function and exercise exercise produces a decrease in neutrophil adherence and bactericidal capacity in conditioned athletes but not untrained subjects. conversely, phagocytic activity is improved in untrained men but not athletes.9 it is tempting to speculate that the leukocytosis of exercise could protect athletes from bacterial infection. however this is unlikely as the response is so acute and transient and there is no evidence that regular exercise produces long-term adaptation in leukocyte numbers, mobilisation or function. the mechanisms of exercise leukocytosis at rest, more than half o f the body’s mature leukocytes are sequestered in the lungs, liver and spleen. an increase in cardiac output and perfusion of the microvasculature, as well as adrenergic-receptor m edi­ ated changes in the interaction between leukocytes and endothelial cells of the capillaries would mobilise this pool of marginal cells into the blood stream .1011 epinephrine is a potent beta-adrenergic agonist, and high intensity exercise is known to induce a rapid increase in the density of betas adrenoreceptors.12 cortisol, while inducing a strong and sustained neu trophila, also inhibits the entry of lymphocytes into the circulation and facilitates their egress from the blood into other lymphoid compartments.13 accordingly, this post-exercise leukocytosis is predominantly a neu­ trophilia with a c o n c u r r e n t lymphopenia. immature leukocytes may also be released from the bone marrow. hemoconcentration effects are minimal. the mechanisms o f exercise leukocytosis therefore involve a redistribution of existing cells, rather than synt hesis of new cells. mccarthy and dale’s2 model of exercise leukocytosis is based on the differential activ­ ity of catecholamines and cortisol. blood concentra­ tions of epinephrine and cortisol rise when exercise intensity exceed 60% of voa max. epinephrine effects circulating leukocyte numbers during brief (<1 hr) exer­ cise, while cortisol only comes into play after two to three hours exercise and during recovery. there is a high correlation between serum cortisol .levels and total white cell count post-exercise.1410 in fact, belgian researchers have proposed that the 3h post-exercise neutrophil-to-lymphocyte ratio is a reliable index of exercise-induced stress in race horses because of its high correlation with post-exercise plasma cortisol con­ centrations.10 between 3 -4 hours, the total number of leukocytes in the vascular compartment seem s to reach a plateau, representing a temporary homeostatic read­ justment to the prevailing higher plasma cortisol con­ centration.2 exercise and lymphocytes resting lymphocyte numbers are usually normal in ath­ letes.2 a lymphocjtosis, proportional to exercise inten­ sity and fitness level occurs during and immediately after exercise of as little as 10 minutes to several hours 4 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) duration. return to baseline levels follows a similar tiine-sequence to that o f the leukocytes, but lym pho­ cytes numbers may drop to below pre-exercise levels during recovery. the various lymphocyte subsets appear to respond differently to exercise. this is partly explained by their complexity and the techniques used to measure them. what has been consistently demonstrated is that there is a proportionally greater increase in b cells, natural killer (nk) cells and monocytes than in t cells. the t:b ratio decreases, although there does not appear to be a significant change in the t helper:'!' suppressor ratio. most of these changes are transient and exercise train­ ing has no long-term effect on lymphocyte distribution.17 cannon18 argues that these acute and transient effects are often attributable to circadian rhythms or hemo concentration effects. studies claiming post-exercise ‘ immunosuppression’ rarely include measurements from non-exercising time controls, which may well exhibit a similar pattern o f leukocyte distribution due simply to circadian variation. effects of exercise on lymphocyte function determination of the proliferative response (blastogen esis) of human lymphocytes upon stimulation with mitogens in vitro is a well-established test to evaluate tlie functional capacity o f t lymphocytes. exhaustive exercise suppresses mitogen-stimulated proliferation of separated mononuclear cells by 50%, while short to moderate exercise has little or no effect.19 the decrease in mitogenic response is probably due to the relative decrease in t cells compared to nk cells in the post­ exercise in vitro assay sample. that is, there is a small­ er percentage of cells that respond to mitogens, due to the differential changes in circulating lymphocyte num­ bers.3 both cortisol and epinephrine inhibit mitogen induced lymphocyte proliferation directly and indirect­ ly via their effects on interleukin-2 production." this may explain the reduction in lymphocyte proliferation after high but not moderate intensity exercise. training may attenuate this suppression.™ mechanisms oflymphocvte activation evidence from canine but not human studies is that exercise stimulates lymph flow from skeletal muscle and that this ‘tissue pump’ delivers large numbers of lymphocytes to the circulation, as does an increased perfusion o f the lung.11 epinephrine promotes exercise lymphocytosis, while cortisol exerts a limiting effect. exercise and innate immunity the principle components o f innate immunity are struc­ tural and chemical barriers that limit entry into the host. this first line o f defence is augmented by phago­ cytic cells that kill foreign micro-organisms and release soluble factors that initiate the immune response. phagocytic functions increase, decrease or remain unchanged, depending on the type, of exercise and the source o f cells.21 macrophage activity appears to be enhanced by exercise, and there is a suggestion that exercise may enhance macrophage secretion o f tumour necrosis factor (tnf) that inhibits tumour growth. neutrophil activation and microbicidal activity is either enhanced or michanged by exercise,020 and appears to be lower in trained athletes than non ath­ letes.20 moderate exercise is associated with a pro­ longed improvement in the killing capacity of neu­ trophils, while exhaustive exercise may have the oppo­ site effect. both complement and c-reactive protein (crp) levels tend to be lower in athletes than non-ath­ letes, but increase after prolonged exercise.u-23 while the lower resting acute phase protein concentrations may represent adjustments to chronic training-induced inflammation the implications of these changes for resistance to infection is tin known.'1 exercise and humoral (anti-body mediated) immunity' the b lymphocytes, when exposed to a specific antigen and/or in co-operation with macrophages, t lympho­ cytes and their soluble products, replicate and mature into plasma cells. these synthesise, and secrete five classes o f antibodies, the immunoglobulins igg, igm, iga, igg and igd, which react with, and lead to the destruction o f the antigen. resistance to infection is due in part to the presence of sufficient levels o f serum and secretory immunoglobulins, especially the antigen specific igg and iga. a pool o f antigen-specific lym­ phocytes forms the basis o f long-term immunity for an individual. exercise and the immunoglobulins most researchers have reported trained athletes to have resting serum immunoglobulin (ig) levels within the normal reference range and similar to those of sedentary controls.1424 intense exercise during regular training does not appear to alter serum ig levels, although some elite athletes may experience low levels during the competitive season.2520 serum ig changes following less than 401tm of running are generally minor, but can be depressed for up to two days after completion o f a run longer than 40km . prolonged endurance exercise has been associated with low sali­ vary iga levels.2' in contrast, moderate exercise training mav even improve ig levels.27 secretary iga is a glue-like substance o f the mucosal barrier that has anti-body activity against certain virus­ es, bacteria and common allergens. exercise-induced decreases (within the clinically normal range) in sali­ vary and nasal wash iga levels have been reported in a variety o f competitive atliletes inducing nordic skiers 2h, cyclists2”, swimmers30, runners", hockey and squash players and kayakers.32 the intensity of the exercise session and the psychological stress o f competition pro­ foundly affect salivary iga concentrations.21 these depressed ig levels are implicated in increased susceptibility to bacterial and viral infections following prolonged exercise. simon1 argues however tliat exercise-induced alterations in secretory antibod­ ies levels are not likely to be functionally significant, as they are so transient. h e points out that the majority of the 1 in 6 5 0 adults who are entirely deficient in iga are healthy and do not experience an mcreased incidence of infection. exercise and immunoglobulin function hi general, following acute prolonged exercise or sever­ al weeks o f heavy exercise training, in vivo and in vitro antibody production, at least in animal models remains unaltered.2”-33 whether in vitro ig synthesis is an accu­ rate reflection o f that occurring in vivo is however debatable. helper t lymphocytes are essential for b cell differentiation and antibody synthesis. as there is a temporary reduction in the t helper ratio after exer­ cise, the in vitro reduction in ig synthesis could simply reflect the change in lymphocyte subsets at the time of sampling. sports medicine march 1996 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) exercise training may also enhance specific antibody formation in response to immunologic challenge. for example, higher titres of serum ig specific to injected tetanus toxoid was observed in males completing a 42km marathon compared to controls. this occurred despite a significant decrease in mitogen-stimulated t cell transformation.7 however the sample size in this experiment was very small (4 runners, 59 controls). trained mice immunised with injected salmonella typhi produced markedly higher specific antibody than did the non-exercising controls.34 mechanisms of exercise-induced immunoglobulin redistribution plasma volume changes explain most o f the acute exer cise-related increases in immunoglobulins, together with an increase in ig-containing ly m p h flow into the vascular compartment/'''’ however, over the long term, baseline ig production does not appear to be affected by exercise, as evidenced by generally normal resting ig levels in athletes (green et al. 1981). there is as yet no explanation for the higher specific antibody response observed after acute exercise and training, although this may represent an enhanced capacity o f the immune system to respond to antigenic challenge.21 exercise and the cytokines monocytes and macrophages exert a pervasive influence on host defences by secreting cytokines, which play a central role in initiating and regulating (lie immune response. principally, these proteins stimulate the cells mediating specific immunity and also induce a wide array of non-specific host defence adaptations.18 there are few published studies on the effects o f exercise on these intracellular messengers. interleukin-1 (il-1) is a protein with pleitropic effects, produced by mononuclear cells in response to endotoxin, immune complexes, phagocytosis and other stimuli such as exercise. interleukin-1 and interleukin 6 (il-6) levels and activity has been reported to increase during or in the recovery period after exer­ cise,15-36'37 and to be higher in endurance athletes at rest compared to non-athletes.38 these observations o f exercise-induced increases in il-1 provide a potentially important link between exer­ cise and host defence mechanisms. firstly, il-1 m edi­ ates the acute phase response to infection and inflam­ mation by, among other things, producing a leukocyto­ sis. it is reasonable to speculate that il-1 exerts a sim ­ ilar effect during exercise. secondly, il-1 increases the activity of both b and t lymphocytes. however, whether this is related to changes in immune functioning has not been established. it is possible that the immun odepressive effects of il-1 are countered by a decrease in the th:ts ratio or other factors that oppose il-1.30 interleukin-2 (il-2) levels in plasma and in vitro il 2 production are reduced following brief maximal exer­ cise3”, possibly because of a shift in the th:ts ratio and the ability o f the lymphocytes to respond to a immuno­ genic challenge. il-2 production following prolonged exercise has not been measured.'1 il-6 release is dependent on il-1, and it is suggested that there is a co-ordinated release of il-1, il-6 and crp during or after exercise, w7hich may be related to muscle damage and proteolysis, or a general inflammatory response.15 38 both interferon (ifn) levels and activity increase tran­ siently after one hour moderate exercise.4" although ifn exhibits anti-viral activity, stimulating cytotoxic cells and inhibiting viral replication the transient and minor fluctuations measured post exercise are not like­ ly to have any biological significance.1 likewise, tumour necrosis factor (tnf) levels are moderately elevated post-exercise in trained and untrained individuals41, but the functional significance is unknown.21 levels o f all cytokines studied to date appear to be within clinically normal ranges, even when elevated after exercise.41 it is impossible to determine the effects on immune functioning of an exercise-induced change in a single cytokine. biological activity of any cytokine depends on a complex network o f interactions, and cytokines may behave differently in vivo compared to in vitro. exercise and cytotoxic cells cytotoxic (killing) activity is exhibited by several types o f immune cells, in particular cytotoxic t lymphocytes, natural killer (nk) cells and monocytes/macrophages. the effects of exercise on cytotoxic cells, particularly n k cells, is currently the focus of much research inter­ est. exercise appears to influence host resistance to both cancer and viral infections, due to its effect on the cytokines involved in resistance to tumour growth and viral infection. exercise and nk cells n k cells, which comprise about 15% of lymphocytes recognise and kill viral ly infected cells, certain tumour cells and some micro-organisms without prior expo­ sure. they also exhibit spontaneous cytolytic activity. total n k activity is generally increased during and immediately after brief, prolonged, moderate and intense exercise, and contributes substantially to the overall lymphocytosis (for review see mackinnon).42 nk cells are selectively recruited into the circulation early in exercise. nk cells have a greater density of betas adrenergic receptors than do other lymphocytes, which explains why circulating levels increase dramatically after high intensity exercise w'hen epinephrine concen­ trations are high.12 possibly epinephrine, il-1, ifn, tnf and b-endorphin act synergistically to augment nk activity during exercise. immediately following exercise the cytotoxic capaci­ ty o f the blood is markedly improved (by 40-100% )w, but the effect is transient. one to two hours after maximal or prolonged exercise, n k activity is low, due to cortisol mediated decrease in total circulating numbers and the inhibitory influence o f prostaglandins firom activated monocytes and neutrophils.44 nieman3 argues that per cell, n k cytotoxic activity is actually increased after high but not moderate intensity exercise. there are simply less nk cells around, due to post-exercise egress to peripheral tissues. however, even this is a transito­ ry effect, as baseline n k activity is restored around 6 hours post-exercise.4'1 resting nk activity in athletes may be slightly elevated compared to non-athletes, but within the normal range.45 exercise and non-specific host defence mechanisms anatomical and physiological barriers form the first line o f defence against infection, by preventing penetra­ tion o f micro-organisms firom the environment and the cutaneous and mucosal surfaces of the body into vul­ nerable body tissues. examples of these non-immuno logical mechanisms are the skin' and mucous m em ­ branes, the cough and gag reflexes, gastric acidity and intestinal motility. the stress of exercise has a negligible effect on non6 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) specific defence mechanisms. strenuous exercise and sports can result in trauma that disrupts the integrity of the cutaneous barrier to infection, but this is not usual­ ly a clinically important problem. maceration through perspiration can predispose to annoying superficial fun­ gal infections such as athletes foot.1 exercise and the acute phase response the acute phase response involves the complement sys­ tem , neutrophils, macrophages, various cytokines and acute phase proteins acting together to clear damaged tissue and initiate repair and regrowth.“ lymphocytes, neutrophils and macrophages are attracted to the injured muscle cells where they variously phagocytize tissue debris and release soluble products such as cytokines which mediate the inflammatory response ,:l during this process, m acrophages produce prostaglandin ea which suppresses nk cell activity. there is speculation that when muscle damage is severe, the immune system , partly disabled by prostaglandin is unable to perform its other host defence duties. that this renders the individual sus­ ceptible to opportunistic infection has yet to be sub­ stantiated by objective measurement.3 the immune response to chronic exercise several studies have made cross-sectional comparisons o f the immune systems of athletes and non-athletes,2445 or followed immune parameters in sedentary' individu­ als undergoing exercise training.17 most of these stud­ ies have failed to demonstrate any important effects of regular exercise training 0 11 circulating concentrations of total leukocytes or lymphocytes or their various sub­ populations. generally, trained athletes have resting serum immunoglobulin levels within the normal refer­ ence range and similar to those of sedentary' controls .27 longitudinal studies o f collegiate teams over a compet­ itive season show decrements in specific immune para­ meters, which coidd however be simply due to estab­ lished seasonal variations in immune function.50 however, the question o f whether the exercise-induced transitory insults to leukocyte functioning are related to illness susceptibility is still open to speculation.21 long term leukocyte function is relatively unaffected and mitogen-stimulated lymphocyte proliferation is not altered by exercise training in young adults.47 suppression o f lymphocyte function has been reported in exhaustively trained athletes48 and neutrophil-killing activity was foimd to be lower in elite athletes com­ pared with untrained controls.22 in contrast, n k cell activity is improved with exercise training.45-43 nevertheless, results from animal studies consistently show that chronic exertion is related to negative changes in immune functioning/'^2 towards an integrated model o f the immune response to exercise there are no data on the effects of exercise 0 1 1 the immune system as a whole, and no models that can fully explain the complex interaction o f the physiologi­ cal responses to exercise and how these influence immune function. while individual models may vary' in complexity, all have neuroendocrine factors playing a pivotal role. psychoneuroimnnmology (pni) or behavioural immunology is an emerging field that is concerned with the study of the relationships among psychological vari­ ables (such as stressors or affective states such as anx­ iety and depression), the nervous system and the immune system. it is generally accepted that there is a two-way communication between the neuroendocrine and immune systems. exercise, as a form o f physical stress can be consid­ ered one of the many lifestyle factors such as diet, sleep or work stress that influence the immune system. in addition, exercise training may reduce negative affec­ tive states, increase the release o f endogenous opiates, reduce hpac activation and enhance immunity.53 many hormones capable o f immunomodulation are released during exercise, and affected by. training. smith and weidemann51 propose that moderate exer­ cise increases the release of immunostimulatory hor­ mones, such as growth hormone, prolactin and b endor­ phin, as well as cytokines such as il-2 and tnf. immonosuppressive hormones such as cortisol and cat­ echolamines are generated during intense exercise. the latter would provide some explanation for the anec­ dotal evidence o f increased rates o f infection in elite athletes at times o f intense physical and emotional stress such as occurs during major competitions. pedersen and ullum52 propose an ‘open window’ hypothesis. during moderate and severe exercise, immune system functioning is enhanced, but followed by a period o f im num o-depression post-exercise. during this ‘ open window’ period, microbacterial agents may invade the host, and infection be estab­ lished. they suggest that regular moderate exercise may enhance immune functioning, thereby protecting the individual even after a severe exercise bout. exercise, stress and illness can be viewed as three points on a triangle. each has independent effects on the immune system, while being mutually interactive.54 for every individual, there is an optimal level o f regu­ lar physical activity' conducive to illness resistance.54 references 1. simon hb. exercise and immune function. in: ader r, cohen f, eds. psychoneuroimmunology. 2nd ed. new york: academic press, 1991. 2. mccarthy da, dale mm. the leukocytosis o f exercise: a review and model. sports med 1988; 6: 333-363. 3. nieman dc. exercise, upper respiratory tract infection, and the immune system. med sci sport exer 1994; 26: 128-139. 4. galun e, burstein r, a ssia e, tur-kaspa i, rosenblum j, epstein y. changes o f white cell count during prolonged exer­ cise. int j sports med 1987; 8: 253-255. 5. nieman dc, nehlsen-cannarella sl, donohue km, douglas bw, chritton dbw, haddock bl, stout rw, lee jw. the effects o f acute moderate exercise on leukocyte and lympho­ cyte subpopulations. med sci sport exer 1991; 23: 578-585. 6. busse w\v, andersen cl, ilanson pg, folts jd. the effect o f exercise on the granulocyte response to isoproterenol in the trained athlete and unconditioned individual. j allergy clin immunol 1980; 65: 358-364. 7. eskolaj, ruuslcanen o, soppi e, viljanen mk, jarvinen m, toivonen h, kouvalainen k. effect o f sport stress on lympho­ cyte transformation and antibody formation. clin exp immunol 1978; 32: 339-345. 8. soppi e, vatjo p, eskola j, laitinen la. effect o f strenuous physical stress on circulating lymphocyte number and junction before and after training. j clin lab immunol 1982; 8: 43-46. 9. lewicki r, tchorzewski h, denys a, kowalska m, golinslca m. effect o f physical exercise on some ;xirameters o f immunity in conditioned sportsmen. int j sports med 1987; 8: 309-314. sports medicine march 1996 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 10. ahlborg b, ahlborg g. exercise leukocytosis with and without beta-adrenergic blockade. a cta med scand 1970; 187: 241-246. 11. muir al, cruz a , martin ba, thmmasen h, belzberg a. hogg jc. leukocyte kinetics in the human lung: role o f exercise and catecholamines. j appl physiol 1984; 57: 711-719. 12. murray dr, irwin m, rearden ca, ziegler m, motidsky ii. maisel a s. sympathetic and immune interactions daring dynamic exercise: mediation via a beta-adrenergic-dependent mechanism. circulation 1992: 86: 203-213. 13. cupps tr, fauci as. corticosteroid-mediated immuno-reg ulation in man. immunol rev 1982; 65: 133-155. 14. nieman dc, berk ls, simpson-westerberg m, arabatzis k, youngberg s, tan sa, lee jw, eby wc. effects of long endarance running on immune system parameters and lympho­ cyte function in experienced marathoners. int j sports med 1989; 10: 317-323. 15. weight lm, alexander d, jacobs p. strenuous exercise: analagous to the acute phase response ? clin sci 1991; 81: 679 683. 16. linden a, a rt t, am ory ii, massart am, burvenich c, lekeux p. quantitative huffy coat analysis related to adreno­ cortical function in horses during a three day event competition. zentralbl veterinarmed 1991; 38: 376-382. 17. nehlsen-cannarella sl, nieman dc, balk-lamberton aj, markoff pa, chritton dbw, gusewitch g, lee jw. the effect o f moderate exercise training on the immune response. med sci sport exer 1991; 23: 64-70. 18. cannon jg. exercise and resistance to infection. med sci sport exer 1993; 74: 973-981. 19. hoffman-goetz l, keir r, thorne me, houston c. chronic exercise in mice depresses t lymphocyte mitogenesis in vitro. clin exp immunol 1986; 66: 551-557. 20. hoffman-goetz l, thorne rj, houston me. splenic immune responses following treadmill exercise in man. can j physiol pharmacol 1988; 66: 1415-1419. 21. mackinnon lii. exercise and immunology. champaign, il: human kinetics books, 1992. 22. smith ja, telford rd, mason ib, weidemann mj. exercise, training and neutrophil microbicidal activity. int j sports med 1990; 11: 179-187. 23. dufaux b, order u, geyer h, hollmann w. c-reactive pro­ tein serum concentrations in well-trained athletes. int j sport med 1984; 5: 102-106. 24. green rl, kaplan ss, rabin bs. stanitski cl, zdziarski u. immune function in marathon runners. ann allergy 1981; 47: 73-75. 25. kassil gn, levando va, suzdal’nitskii rs, pershin bb, k u z’min sn. neuro-humoral regulation o f immune homeostasis during culaptation to extreme stresses using modern sport as a model. sport train med rehab 1988; 1: 61-65. 26. wit b. immunological response o f regularly trained ath­ letes. biol sport 1984; 1: 221-235. 27. nieman dc, nehlsen-cannarella sl. the effects o f acute and chronic exercise on immunoglobulins. sports med 1991; 11: 183-201. 28. tomasi tb, trudeau fb, czerwinski d, erredge s. immune parameters in athletes before and after strenuous exercise. j clin immunol 1982; 2: 173-178. 29. mackinnon lt, chick tw, van a s a , tomasi tb. d ecreased secretory immunoglobulins following intense endurance exercise. sport train med rehab 1989; 1: 209-218. 30. tharp gd, barnes mw. reduction o f saliva immunoglobu­ lin levels by swim training. e urj appl physiol 1990; 60: 61-64. 31. muns g, liesen h, riedel ii, bergmann k-ch. influence o f long-distance running on iga in nasal secretion and saliva. deutsche zeit fur sportmed 1989: 40: 63-65. 32. mackinnon lt, ginn e, seymour g. effects o f exercise dur­ ing sports training and competition on salivary iga levels. behaviour and immunity proceedings o f the 1990 australian behavioural immunology group scientific meeting. boca raton fl: crc press, 1992. 33. k east d, cameron k, morton a r . exercise and the immune response. sports med 1988; 5: 248-267. 34. liu yg, wang sy. the enhancing effect o f exercise on the production o f antibody to salmonella typhi in mice. immunol lett 1986/87 14: 117-120. 35. wetts cl, stern jr, hecht lh. hematological changes fol­ lowing a marathon race in male and female runners. eur j appl physiol 1982; 48: 41-49. 36. cannon jg, evans wj, hughes va, meredith cn, dinarello ca. physiological mechanisms contributing to increased interleukin-1 secretion. j appl physiol 1986; 61: 1869-1874. 37. cannon jg, kluger mj. endogenous pyrogen activity in human plasma after exercise. science 1983; 220: 617-619. 38. evans wj, meredith cn, cannon jg, dinarello ca, frontera wr, hughes va, jones bh, knuttgen hg. metabolic changes following eccentric exercise in trained and untrained men. j appl physiol 1986; 61: 1864-1868. 39. lewicki r, tchorzewski h, majewska e, nowak z, baj z. effect o f maximal physical exercise on t-lymphocyte subpopula­ tions and on interleukin-1 (il-1) and interleukin-2 (il-2) pro­ duction in vitro. int j sports med 1988; 9: 114-117. 40. viti a , muscettola m, paulesu l, bocci v, almi a. effect o f exercise on plasma inteferon levels. j appl physiol 1985: 59: 426-428. 41. espersen gt, elbaelc a, aernst e, toft e, kaalund s, jersild c, grunnet n. effect o f exercise on cytokines and lymphocyte sub-populations in human peripheral blood. apmis 1990; 98: 395-400. 42. mackinnon lt. exercise and natural killer cells: what is the relationship ? sports med 1989; 7: 141-149. 43. mackinnon lt, chick tw, van a s a , tomasi tb. effects o f prolonged intense exercise on natural killer cell number and function. in dotson co, humphrey jh, eds. exercise physiology: current selected research. new york: ams press, 1988; vol 3: 77-89. 44. pedersen bk, tvede n, hansen fr, andersen v, bendix t, bendixen g, et cd. modulation o f natural killer cell activity in peripheral blood by physical exercise. scand j immunol 1988; 27: 673-678. 45. pedersen bk, tvede n, chrisensen ld, klarlund k, kragbak s, iialkjaer-kristensen j. natural killer cell activity in peripheral blood o f trained and untrained persons. int j sports med 1989; 10: 129-131. 46. kushner i. the phenomenon o f the acute phase response. ann ny a cad sci 1982; 389: 39-48. 47. macneil b, hoffman-goetz l, kendall a, houston am, arumugam y. lymphocyte proliferation responses after exercise in men: fitness, intensity and duration effects. j appl physiol 1991; 70: 179-185. 48. fry rw, morton ar, garcia-webb p. biologic response to overload training in endurance sports. eur j appl physiol 1992; 64: 335-344. 49. nieman dc, tan sa, lee wj, berk ls. complement and immunoglobulin levels in athletes and sedentary controls. int j sports med 1989; 10: 124-128. 50. levi fa, canon c, touitou y, reinberg a, mathe g. seasonal modulation o f the circadian time structure o f circulat­ ing t and natural killer lymphocyte subsets from healthy sub­ jects. j clin invest 1988; 81: 407-413. 51. smith ja, weidemann mj. the exercise an immunity para­ dox: a neuroendocrine/ cytokine hypothesis. med sci res 1990; 18:749-753. 52. pedersen bk, ullum h. nk cell response to physical activ­ ity: a possible mechanism o f action. med sci sport exer 1994; 26: 140-146. 53. laperriere a , ironson g, antoni mh, schneiderman n, klima n, fletcher ma. exercise and psychoneuroimmunology. med sci sport exer 1994; 26: 182-190. 54. mackinnon lt. current challenges and future expecta­ tions in exercise' immunology: back to the future. med sci sport exer 1994; 26: 191-194. □ 8 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) exercise and upper respiratory tract infections: a review em peters msc(med) abstract despite equivocal findings in early laboratory and long­ itudinal studies investigating the relationship between exercise and infection risk, recent carefully controlled work appears to point towards a paradoxical response of the host defence and immune systems to endurance exercise; whereas long-term regular training is thought to stimulate these systems, acute exposure to exhaus­ tive endurance exercise has been associated wiitli tran­ sient suppression thereof. several studies have con­ firmed that athletes are more susceptible to upper res­ piratory tract infection (urti) symptoms following par­ ticipation in competitive marathon and ultramarathon running events, while others have produced evidence of a protective effect and lower incidences of urti symp­ tom s following prolonged endurance training pro­ grammes. nieman (1993) proposes a “j ” shaped rela­ tionship between urti risk and exercise intensity, whereas pederson and ullman (1994) describe an “ open window” period during which the athlete is most vulnerable to infection. how is the athlete best man­ aged (hiring periods o f heavy training and competition? what influences the size o f the “ open window” and urti risk? these are some o f the questions to be addressed in this paper..... introduction upper respiratory tract infection (urti) frequently results in inopportune disruption o f the t r a i n i n g pro­ grammes o f serious athletes. in 1 9 7 5 ryan et al1 reached the conclusion that “upper respiratory illness causes more disability among athletes than all other diseases combined.” this was confirmed by berglund and hemmingsson2 who reported that infectious dis­ eases, of which urti was the most common, was the main medical reason for absence from training in elite skiers monitored over a 12 month period [figure 1], regular prolonged exercise, is however, generally recognised as a therapeutic modality providing numer­ ous health benefits; cardiovascular, respiratory and metabolic adaptations have indeed been linked to longevity.'* many also believe that regular aerobic exer­ cise training improves their resistance to infection and anecdotal reports of fewer colds and urti infections in well-conditioned athletes abound.4 correspondence: edith m peters, division of physical education, university of the witwatersrand, private bag 3, wits 2050, johannesburg, south africa. studies investigating urti incidence in sportsper sons reveal a paradoxical response. on the one hand, a high level o f physical conditioning has, in few carefully controlled recent studies, provided evidence o f a lower incidence o f infection symptoms which is possibly asso­ ciated with chronic immunomodulation and an increased resistance to infection.5" ’7 8 on the other hand, overtraining and the combined psycho-physical stress of competitive endurance events and acute bouts of exhaustive endurance exercise have been linked to an increased incidence of urti symptoms possibly associ­ ated with transient suppression o f host and immune defences.910'1112 o veru se injuries iiihiii acu te injuries u r t i s 3 o th er infectious diseases o th e r causes figure 1: urti, the main medical reason for absence from training in elite swedish cross country skiers. data adapted from berglund and hemmingsson.' nieman13 has graphically depicted the relationship between exercise and urti incidence in a “j ” shaped model proposing that a moderate and regular exercise load can reduce urti risk to below that found in seden­ tary population, whereas a high volume and intensity of exercise can increase urti risk to almost double that found in the sedentary population [figure 2]. it is thus the purpose of this review to provide a brief overview o f the epidemiological and laboratory evidence which is currently available in support of this dual response and to provide practical guidelines to die ath­ lete, coach and medical practitioner regarding the pro­ phylactic management o f die athlete during periods of increased susceptibility to infection and treatment of the athlete once urti has set in. chronic training and urti infection risk a number of longitudinal studies have been designed specifically to consider the chronic effects of repeated bouts of exercise (ie training and racing) on the inci­ dence of urti. while linde14 found that on average elite danish orienteers experienced 2 ,5 infectious episodes (lasting for more than three days) during a one-year period as opposed to 1 ,7 in non-athletic con­ trols and a higher average duration o f symptoms, health et al1", examining the illness patterns of a cohort of 53 0 male and female runners over a period of 12 sports medicine march 1996 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) regular competition inactivity training overtraining high i moderate urti risk \ j lowi i i i i low moderate high intensity and volume of exercise figure 2 : “j ” shaped model o f relationship between ranging amounts o f exercise and risk o f urti. this model suggests that moderate exercise may lower risk o f respiratory infection below that evidenced in sedentary individuals while excessive amounts may increase, the risk. adapted with permission from nieman.''' months, found that the average number o f self-reported illness patterns per runner per year was only 1.2 and suggested that chronic high mileage training may pose as great a risk of an infectious episode as racing.1" a rel­ atively low incidence o f urti symptoms was confirmed by berglund and hemmingsson2 who reported an aver­ age o f 1 ,5 and 1 ,8 8 urti infections per year in groups o f swedish national team [n=36] and elite college [n = 1 3 6] cross country skiers. t h is study further revealed the incidence of urti symptoms to be great­ est in the winter months. osterback and qyamberg10, surveying the incidence o f respiratory infections in 12yr old children participating in swimming, ice-hockey and gymnastics on a regular basis, however, found no differ­ ences in infection rates when these children were com­ pared to an age-matched control group. schouten et al17 studied the relationship between the incidence and duration of urti symptoms (over a 6 month period) and level of sport activity in 9 2 men and 1 0 7 women participating in the amsterdam growth and health study and found statistically negative corre­ lation between the incidence of urti symptoms and the level of sport activity in the women only. variance in the findings of these longitudinal studies could well be attributed to disparity in the quality, quantity and frequency of the training completed by the subjects studied. more recent randomized, well-con­ trolled studies on circulating immune system variables and incidence o f urti symptoms, however, may sup­ port the common belief that a moderate level of physi­ cal training may lower infection risk. nieman et al(i 7 performed two tightly controlled con­ secutive studies which investigated the effect of endurance training on the incidence of urti sympto­ matology. firstly, in a randomised controlled study of 3 6 women (mean age 3 6 years) five 4 5 min sessions, wk 1 of brisk walking at 60% heart-rate reserve resulted in a significant reduction in urti symptomatology with less than 50% the number o f (lays with symptoms in the walkers than in the sedentary control group over the 15 week period7 [figure 3]. in a later study urti sympto­ matology in a group of highly conditioned elderly female subjects who exercised moderately each day for about 1,5 hr | n=12| was compared to a group exercising for 4 0 min 5 times per week [n=14] and control group who only participated in calisthenic exercises [n=16] over a 12 wk period.7 the lowest incidence (8%) o f urti was reported in the highly-conditioned group who exer­ cised daily, followed by the next lowest incidence in the group which trained at a moderate intensity 5d.w k' over the 12 wk period [figure 4], a s the highly-condi tioned distance runners trained more frequently than the lower-distance runners (4 .6 vs 2 .7 sessions per week), frequency of exercise was suggested as a factor which may improve immunosurveillance.7 number of symptom days/incident j p < 0,05 ____ i (1990) exercise group nonexercise group figure 3: mean number o f symptom days per ur ti inci­ dent in exercise and non-exercise groups during a 15 wk study period. adapted with permission from nieman et al." ‘ % in c id e n c e of u r t i 3 0 s y m p to m a to lo g y c h i-s q u a re = 6.3 6 , p = 0 ,0 4 2 ■ ■ ■sssr b— w a lk in g s e d e n ta ry g ro u p g ro u p figure 4 : incidence o f ur ti ( expressed as a percentage o f the group) during a 12 wk study period in highly con­ ditioned, walking and sedentary control groups women (n = 4 2 ). adapted with permission from nieman et al.7 10 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mackinnon and hooper’ examining secretory iga response to various exercise conditions, support these find­ ings showing evidence of a cumulative effect of intense daily exercise on local mucosal resistance against pathogenic organisms causing urti. a group of well trained australian swimmers presented with significantly higher secretory iga levels than “stale” , overtrained swim­ mers over a 6 month session, hi contrast, previous studies have shown that salivary iga levels are depressed in elite well trained athletes'8 "1 and linked these to an increased risk of infection in elite athletes.19 these data may, howev­ er, also point to an endurance training threshold above which urti risk is increased supporting the “j ” shaped model proposed by nieman.13 acute effects of competitive pro­ longed exercise on urti risk a number o f epidemiological surveys performed locally and abroad in the last 12 years suggest that athletes engaging in marathon mid ultramarathon type events are at increased risk for urti during the two-week post race period the first preliminary investigation was conducted by peters and bateman20 at the 1 9 8 2 two-oceans ultramarathon (5 6 km) in cape town. a simple epi­ demiological survey on 1 50 successful finishers in this race, and their age-matched non-running controls who resided in the same households, revealed that whereas a mere 15.3% of the non-running controls reported urti symptoms during the two-week post-race period, thirty-three percent o f the runners completing the race reported urti symptoms during this same period [figure 5]. the incidence o f urti symptoms was high­ est in the fastest runners (p > 0 .0 1 ) and 47% o f those completing the 5 6 km race in less than 4 hrs reported post-race urti symptoms. sore throats and nasal symptoms were the most prevalent with more than 80% of the symptoms reported lasting more than 4 days. the finding o f a significantly higher incidence of urti symptoms among runners during the post-race period was confirmed by peters in 1 9 8 9 21 when the study was repeated at tlie milo korkie marathon , a 56 km race taking place between johannesburg and pretoria [figure 5|. nasal symptoms and sore throats were once again the m ost prevalent o f self-reported symptoms during the two-week post-race period and 39% of symptoms lasted more than 7 days. in this stud}7, it was the runners in the low pre-race training status group who had the highest incidence o f post-race infection. to date, an increased incidence o f post-race urti symptoms has, however, only been reported following events falling into the marathon and ultramarathon cat­ egories. a two-mont h investigation conducted into the preand post-event incidence of urti in a group o f 27 3 participants in 5 ,1 0 and 20 km events in california22 revealed no increase in urti incidence in the runners during the 7-d post race period when compared to the incidence in the week prior to the race. although the urti incidence was highest (33.3% ; p = 0 .0 9 2 ) in run­ ners completing less than 25 km.wk'1 in training, a correlation between pre-race training distance mid fin­ ishing tim es in the race was not found. a s intensity of training is also an important factor in the preparation for these shorter events, weekly training distance may not provide an accurate reflection of pre-race training status in participants in shorter races. runners controls (nonmnners) figure 5: the incidence o f u rti symptoms during the post-race fortnight in runners completing 5 6 km ultramarathon at sea level and moderate altitude and matched sedentary controls. data from peters and an investigation into the urti symptom incidence in 2311 participants before and after the los angeles marathon(lam)i! revealed an increase in odds ratio of infectious episodes (ie) with an increase in pre-race training distance (km .w k1) (p = 0.04). reported inci­ dence o f illness was highest in those runners who com­ pleted >97kni,wk l while training in preparation for the event. o f the 1 8 2 8 lam competitors without infectious episodes (ie) before the race, 12.9% reported ie during the week following lam vs 2.2% in controls (well trained non-participating runners). these researchers concluded that runners may experience increased odds for ie during heavy training or following a marathon race. more recent nutritional intervention studies per­ formed by peters et al2425-20 on participants in the 9 0 ism comrades marathon, also confirm these findings of greater incidence o f infection in the runners during the post-race fortnight. o f interest are the observations, that in the case of the 9 0 km ultramarathon, both con­ ditions of “ under-” and “ overtraining” appeared to pre­ dispose to higher post race urti risk. 242s2li recent hypotheses supported by laboratory findings the paradoxical response to exercise a perspective which explains the dual, paradoxical response to exercise is provided by sm ith and weiderman27 who propose that while moderate exercise activates the immunostimulatory release of growth hor­ mone, prolactin mid cytokines into the circulation resulting in both neutrophilia and increased neu­ trophilic activity27,28, during very exhaustive prolonged exercise, the immunosuppressive arm of the pituitary adrenal axis is activated with subsequent release of acth and cortisol and suppression o f the activity of the polymorphonuclear neutrophils(pmns.)27 a further explanation o f the exercise paradox is con­ tained in the theory that initial pro-oxidative effect on pmn function becomes i m m u n o s u p p r e s s i v e as exercise is prolonged and microbicidal reactive oxygen species produced by the pmns have an auto-oxidative effect reducing the “killing capacity” of the pmns.20 this was recently confirmed in a study conducted on the nasal sports medicine march 1996 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) lavage of runners completing a 20 lan event.'” although the total number of pmns rose, percentage active phagocytes and munber o f ingested microorganisms were reduced/*1 further smith et al29, comparing neutrophil oxygena tive activity in elite trained australian cyclists to that in untrained subjects, showed that endurance training decreases the auto-oxidative phagocytic activity in the pmns. further evidence of reduced oxidative act ivity in trained individuals has most recently been reported by pyne et al31 who in a study conducted on elite swimmers over a 6 month period showed that (i) elite swimmers undertaking intensive training have a significantly lower neutrophil oxidative activity at rest than do age and sex-matched sedentary individuals and (ii) aspects o f oxidative activity in swimmers are further sup­ pressed during periods of strenuous training. in this study the extent o f the suppression did, however, not appealto be of clinical significance as no significant dif­ ference was reported in urti incidence between swim­ mers and sedentary individuals.31 increased post-event susceptibility to urti consistent evidence exists of increased post-race urti symptomo] ology in runners competing intensively in events o f the marathon-ultramarathon category. many existing laboratory findings also appear to lend support to these epidemiological findings and, in particular, the recent hypothesis of pederson and ullman32 that the during first few hours following strenuous exertion, an “ open window” exists. this danish group contend that previously reported reversal of the exercise-induced increment in leucocyte number,33-34'35-3g'37 commonly referred to as a “biphasic” response”, contributes, together with the post-exercise decrease in nk cell number3238, complement39 and mucosal iga levels’’, to transient immunosuppression during this open window period [figure 6]. pederson and ullman suggest that, at this time, the athlete is most vulnerable to infection; microbacterial agents can invade the host and infec­ tions are easily established [figure 6]. according to the findings of nieman91335 the phase o f transitory immuno­ suppression lasts between 6 and 2 0 hours post-exer­ cise.35 figure 6: the open-window hypothesis o f pederson and ullman:12 severe exercise is followed by a period o f tran­ sitory immunodepression during which the athlete pos­ sesses an increased susceptibility to infection. adapted from pederson and ullman.12 management of the athlete ... practi­ cal guidelines for athlete, coach and clinician advice for the athlete in possession o f urti symptoms the effects o f systemic infections oil impairing muscle and circulator}^ function and reducing physical work capacity are well established.™ nieman9 thus proposes that if an athlete experiences sudden and unexpected deterioration in performance during training or compe­ tition, viral infection should be suspected. w hile fitzgerald41 warns that exercising during the incubation period may worsen the illness, participation during the presence of systemic infection is generally regarded as counterproductive resulting in both poor performance and a prolongation o f the recovery period.12 in view of the additional risk o f myocarditis, a recognized, although rare cause o f death in exercising individuals possessing influenza virus42, athletes‘with constitution­ al symptoms of infection should not be expected to par­ ticipate in competition; even strenuous training should be discouraged in the presence of fever, myalgia, swollen lymph glands, extreme tiredness or other symptoms which are suggestive o f systemic infection.12 two to four weeks should probably be allowed before resuming hard training.9 however, in the case o f mild common cold with no constitutional symptoms, complete interruption of exercise schedules is not generally required and mild exercise does not appear to be contraindicated. in fact, som e individuals report relief o f symptoms, probably, according to sim on12, because o f the increased mucous flow associated with exercise. sim on12 recom m ends gentle stretching sessions, permitting ordinary daily activities to the limit of tolerance with a programme of graded aerobic exercise and reassurance on resumption o f training. m ost clinical authorities in this area12*' recommend that regular training may be safely resumed a few days after the resolution of symptoms and warn that adm o­ nitions for prolonged bed rest are responsible for deconditioning which can give rise to protracted fatigue even after infection has subsided. eichner43 recommends a “neck-check” . h e suggests that if the athlete has “below-tlie-neck” symptoms such as aching muscles, a hacking cough, vomiting or diarrhoea, all training should be halted; in the case o f “ above-the-neck” symptoms including stuffy or runny nose, sneezing or a scratchy throat, he recommends that at hletes “ go ahead and plough cautiously” through their scheduled work-out. “ if, after 10 minutes, your head is clear and you feel better, you can speed up and finish your workout. if, instead, your head pounds and you feel like you are running through water, stop, go home and rest!” , advises eichner. in terms o f the use o f cold remedies, caution is advised. most south africans recall the unfortunate controversy surrounding the stripping of the title from comrades gold-medallist, chari matheus, in 1992. m ost cold rem edies do contain sympathominetric agents which are on the list o f banned substances. disqualification o f athletes from high-level competitive events is thus often a possibility when cold remedies are being used. 12 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the advisability athletes using anti-biotics when con­ tracting an apparently severe local bacterial infection, is an area which does not yet appear to have been investi­ gated. whereas this would no doubt assist in early com­ bating o f the infectious microorganisms and prevent extension of nasal infections into the lower respiratory tract and ears, hence resulting in a shortening o f the lay-off period, anecdotal reports o f transitory periods of general weakness and lethargy resulting from anti-biot­ ic ingestion, do abound. a t this stage it would appear that athlete and clinician would need to weigh up the advantages of a greater possibility o f overcoming the infection sooner against the transitory period o f reduced performance which may result from the intake o f anti-biotics. a s large individual differences in response to administration o f anti-biotics may also exist, well controlled clinical studies are needed in this area. prophylactic measures (1) avoidance o f exposure to infectious agents since endurance exercise is associated with muscle cell damage and an increased intake o f potential pathogens through increased ventilator}7 flow rates, weidnerw sug­ gests that particularly during the winter months, expo­ sure to the cold virus in crowded dormitories, class­ rooms, and gymnasiums perhaps accounts for the high incidence o f colds during the cooler months. he further recommends “careful handwashing, avoidance o f skin to-skin contact or contact with contaminated tissues, sporting equipment, and appliances.” (2) immunization o f athletes a t present, the evidence regarding effectiveness of the immunization of athletes against influenza appears to be anecdotal and variant; successful in some individu­ als, but bringing on flulike symptoms in others. melman43 reports the use o f the anti-viral agents aman­ tadine hydrochloride and rimantadine hydrochloride which are both effective against influenza a as a pro­ phylactic measure among the group when the first ath­ letes develop flulike symptoms. this may be particular­ ly helpful for athletes who play winter sports as close contact among teammates can result in rapid spread of influenza and thus disrupt the whole season.13 (3) enhanced intake o f vitamin c recent placebo-controlled studies perform ed on com rades athletes'"'20 have provided evidence of decreased incidences o f urti symptoms dining the post-race “open window” period following three weeks o f supplementation with vitamin c, and beta carotene vitamin c and e combinations. in both studies a total daily intake o f approx l g vit c a day resulted in a sig­ nificantly lower incidence o f urti symptoms during the t wo-week post-race period w7hen compared to the inci­ dence in runners receiving placebo’s. we hypothesised that phagocytic production o f reactive oxygen species (ros) during prolonged exercise suppressed neu tophilic function and that the anti-oxidant properties of vitamin c contributed to a neutralization o f the ros, lifting the transient post-race immunosuppression. although these hypotheses are supported by laboratory work on patients possessing auto-immune respiratory disorders and a link between plasma vitamin c levels and neutrophilic activity has been established, it does require further verification on athletes participating in ultradistance events. a t this stage, anecdotal reports of many coaches w7ho find it o f benefit to increase vitamin c intake o f athletes in heavy training, particularly dur­ ing the whiter months, do abound. a s vitamin c is w7ater-soluble and no negative side-effects have been documented at these levels, an enhanced vitamin c intake is not contra-indicated as a prophylactic mea­ sure. (4) training progression careful attention should be paid by coaches to slow7 pro­ gression in training intensity and duration and the avoidance o f overtrained conditions and the resultant immunocompromising effects thereof.*’ coaches report that more frequent, less intense sessions, have been shown to be more effective in building resistance to infection than very heavy training sessions at less fre­ quent intervals. a s evidence in this field is largely anec­ dotal, w7ell controlled studies are, how7ever, required. conclusion although many findings in this field remain inconclu­ sive, current evidence would appear to suggest that w7hile exercise provides favourable physical and psycho­ logical stress, a therapeutic and immunostimulatory effect is obtained. it would seem that once exercise is too intense, frequent and/or long in dmation, particu­ larly w7hen coupled w7ith exposure to pathogenic microorganisms, the favourable stress situation devel­ ops into one of distress and a concomitant increment in susceptibility to infections, results. greater aw7areness o f the predisposing factors can assist coach, athlete and clinician in lessening the onslaught and reducing the length o f the lay-off period when the athlete is exposed to a high bacteriological/virological count. references: 1. ryan aj, dnlrymple b, dull b, kaden u'.s, lerman sj. round table, respiratory tract infections in sports. phijs sport med 1975;3:29-42, 1975. 2. berglund b, hemmingsson p: infectious disease in elite cross country skiers: a one-year incidence study. clin sports med 1990;2:19-23. 3. paffenberger rs, hyde rt, wing al, hsieh cc: physical activity, all cause mortality and longevity o f college alumni. new engl j med 1986;314:65-613. 4. nash iil. can exercise make us immune to disease? phys sports med 1986;14:25-253. 5. mackinnon lt, hooper s. mucosal (secretory) immune system responses to exercise o f varying intensity and during overtraining. int j sports med 1994;15:s179-183. 6. nieman dc, nehlsen-cannarella sl, markoff pa, balk lamherton h, yang ii, chritton dbw, lee jw, arabatzis k. the effects of moderate exercise training on natural killer cells and upper respiratory tract infections. int j sports med 1990;11:467-473. 7. nieman dc, henson da, gusewitch g, warren bj, dotson rc, butterworth de, nelson-cannarella sa. physical activity and immune function in elderly women. med sc sports exerc 1993;25:823-831. sports medicine march 1996 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 8. crist dm. mackinnon lt, thompson rf. alterbom ha, egan pa. physical exercise increases cellular mediated cytotox­ icity in elderly women. gerontology 1989;35:66-71. 9. nieman dc. exercise. infection and immunity. int j sports med 15:1994;s131-140. 10. shephard rj. shek pn. a thletic competition and susceptibility to infection. clin j sports med 1993:3:75-77. 11. shephard rj. verde tj, thomas so, shek p. physical a ctivity and the immune system. can j sports sci 1991:16:163-185. 12. simon hb. exercise and infection. phys sportsmed 1987;15:135-141. 13. nieman dc. exercise, upper respiratory infections and the immune system. med sci sports exerc 1994:26:128-139. 14. linde f. running and upper respiratory tract infections. scand j sport sc 1987;20-23. 15. heath g iv’ ford es, craven te. macera ca. jackson kl. pate rr : exercise and the incidence o f upper respiratory trad infections. med sci sports exerc 23:152-157. 16. osterback l. qvarnberg y : a prospective study o f respiratory infections in 12-years-old children actively engaged in sports. acta physiol scand 1987:76:944-949. 17. schouten ik7. vershuur p. kemper iicg : habitual physi­ cal activity, strenuous exercise, and salivary immunoglobin a levels in young adults : the amsterdam growth and health study. ini j sports med 1988;9:289-293. 18. tomasi tb, trudeau fb, czerwinski d, erredge s : immune parameters in athletes before and after strenuous exercise. j. clin immunol 1982:2:173-178. 19. von weiss m. fuhrmansky j. lulay r. weiker ii : haufigkeil unci ursache von immunoglohinmangel bei sportlern. dtsch 'a. sportsmeclizin 1985:36:146-153. 20. peters em : altitude fails to increase susceptibility o f ultra marathon runners to infections. s afr j sp med 1990;5: 4-8. 21. peters em, bateman ed : ultramarathon running and upper respiratory tract infections. s afr med j 1983;64:582 584. 22. nieman dc, johansen lm, lee j w : infectious episodes in runners before and after a road race. j sports med phys fitness 1989:29:289-296. 23. nieman dc, johansen lm. lee jw. arahatzis k : infectious episodes in runners before and after the los angeles marathon. 1990: j sports med phys fitness 30: 316-328. 24. peters em. cambell a, pawley l : vitamin a fails to increase resistance to upper respiratory infection in distance runners. 1992:s afr j sports med 7: 3-7. 25. peters em. goet /sche jm. grobbelaar b, noakes td : vitamin c supplementation reduces the incidence o f post-race symptoms o f upper respiratory trad infection in ultradistance runners. am j cl nutr 1993:57:170-174. 26. peters em, goetzschejm, joseph le, noakes td: anti-oxi­ dant nutrient supplementation and symptoms o f upper respiratory tract infections in endurance runners (a b stra ct). med sci sports exerc 1994:26:s218. 27. smith jw. weiderman mj : the exercise and immunity paradox: a neuroendocrine/cytokine hypothesis. medical science research 1990:18:749-753. 28. anderson r. the activated neutrophil formidable forces unleashed. s afr med j 1995;85:124-127. 29. smith j. telford rl). mason ib, weiderman mj. exercise, training and neutrophil microbicidal activity. int j sports med 1990:11:179-187. 30. muns g : effect o f long distance running on polymorphonuclear neutrophil function o f the upper airways. 1993: int j sports med. 15: 96-99. 31. pyne da. baker ms, flicker pa, mcdonald 11/1, telford rd. weiderman mj : effects o f an intensive i2-ivk training pro­ gram hi/ elite swimmers on neutrophil oxidative activity. med sci sports exerc 1995:27(4) -.536-542. 32. pederson bk, ullman h : nk response to physical activity: possible mechanisms o f action. med sci sports exerc 1994;26:140-146. 33. berk ls. nieman dc. youngberg m’s. arabatzis k, simpson-westerberg, tan s/1. eby wc : the effect o f long endurance running on natural killer cells in marathoners. med sci sports exerc 1990:21:207-202. 34. macarthy da, dale mm : the leucocytosis o f exercise. sports med 1988:6:333-363. 35. nieman i)c, berk ls. simpson-westerberg m. arabatzis k, youngberg s. tan s/4. lc'e jw. eby wc : effects o f long endurance running on immune system parameters and lymphocyte in experienced marathoners. int j sports med 1989:10:317-323. 36. gabriel hl, schwartz p, kindermann w. differential mobil­ isation o f leukocyte and lymphocyte subpopulations into the cir­ culation during endurance exercise. eur j apppl physiol 1992:65:529-534. 37. nelson-cannarella sl. nieman dc, balk-lumberton aj, markoff pa, chritton db. gusewilch g. lee jw : the effects o f moderate exercise training on immune response. med sci sports exerc 1991:23:04-70. 38. mackinnon lt : exercise and natural killer cells. what is the relationship? sports med 7:141-149,1989. 39. nieman dc. tan s/4. lee jw, berk ls : complement and immunoglobin levels in athletes and sedentary controls. int j sports med 1980:10:124-128. 40. friman g, wright je, ilback ng. does fever or myalgia indicate reduced physical performance capacity in viral infec­ tions? acta med scand 1985:217:353-361. 41. fitzgerald l : overtraining increases the susceptibility to infection. int j sports med 1991:12.s5-s8. 42. phillips m, robinowitz m, iliggins jr, et a l : sudden car­ diac death in air force recruits. a 20-year review. jama 1986:256:2693-2696. 43. eichner re : infection, immunity and exercise. what to tell patients? phys sports med 1993:21:125-135. 44. weidner to : reporting behaviours and activity levels o f intercollegiate athletes with an url. med sci s/xirls exerc 1994:26:22-26. 45. mellman ml), schelkun pii : immunization strategies for active adults. phys spoils med 1994:22:91-102. u sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) glenbarr pecialist publication free doctors contact: glenbarr publishers 25 bompas road, dunkeld west, 2196. tel: (011) 442-9759 fax: (011) 880-7898 to medical r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) hiv infection in sport: a review of current issues m. p. schwellnus (mbbch, msc(med) sports science, m d, facsm) abstract regular participation in physical activity is well recog­ nized as an important preventative health measure. in contrast, in the last decade, human immunodeficiency virus (hiv) infection has become a major global public health threat. the impact o f h iv infection is likely to have a major effect on the south african population as a whole, including the sporting population. in this arti­ cle issues relating to h iv infection and participation in physical activity are reviewed. these issues include the risk of h iv transmission during sports participation, the effects of h iv infection 0 1 1 exercise performance and the effects of regular exercise on the clinical out­ come of h iv infection. in addition practical guidelines are offered to i) decrease the risk of h iv transmission during spoils participation, and ii) to ensure safe par­ ticipation in physical activity for patients with docu­ mented h iv disease. introduction the health benefits o f regular participation in p h y s ic a l activity are well established (astrand 1992). regular physical exercise is an essential component of a healthy lifestyle. public awareness about the health benefits of regular exercise has resulted in an increase in the num­ ber of participants in all types o f sport (contact and non­ contact sport). it is estimated that more than 4.3% of the south african population regularly participate in sport (hsrc 1982). recent surveys indicate that the m ost popular sport in south africa is soccer followed in popularity by racquet ball sports, athletics and tennis (cosas, 1990). in contrast to positive lifestyle changes such as regular exercise, the h iv pandemic has in recent years become a major global as well as south african public health threat (ijsselmuiden et al, 1988a, schall 1990, schoub et al 1990). the acquired immune deficiency syndrome (aids) was first recognized as a clinical entity by the centers for disease control (cdc) in 1981 with the description o f 5 cases o f pneumocystis carinii infection and 26 cases correspondence: dr. m. p schwellnus sports medicine mrc/uct bioenergetics of exercise research unit department of physiology university of cape town medical school p o box 115 newlands cape town 7725 rep. of south africa tel: (021) 686 7330 fax: (021) 686 7530 o f kaposi’s sarcoma in homosexual males (m mwr 1981a, m m w r 1981b). the first cases o f aid s in south africa were described one year iater (ras et af 1982). the transmission (friediand et al 1987, lifson 1988), clinical features (sher 1 988), epidemiology (moodie 1988a), serology (moodie 1988b), and mortality associ­ ated with human immunodeficiency virus (hiv) infec­ tion have been well described. although there is con­ siderable debate on the precise impact of the h iv epi­ demic on the south african society (schall 1 990), it seem s certain this disease will have a considerable effect on the health o f the south african population, including the sporting population. the association bet ween physical activity and htv infection can there­ fore not be ignored. specific issues that need to be con­ sidered are the risk of h iv transmission (luring sports participation, the effect of h iv infection on sports per­ formance and the effects of regular physical act ivity on the clinical outcome of h iv infection. the aim o f this article is i) to review' the current: knowledge on the risk o f h iv transmission during sports participation, ii) to establish guidelines to reduce the possible risk o f hiv transmission during sports participation, iii) to review7 the effects o f h iv infection 0 1 1 exercise performance and iv) to review the effects of regular physical activity on the outcome of h iv infection. the risk o f h iv transmission during sports participation since its discovery in 1983, the human immunodefi­ ciency virus (hiv) has been isolated in blood, semen, cervical secretions, lymphocytes, serum, plasma, cere­ brospinal fluid, tears, saliva, urine, breast-milk and alvoelar fluid of infected subjects (friediand et al 1987, ziegler et al 1986). however, the transmission o f the virus from one individual to another has only been linked directly to blood, semen and cervical secretions with likely transmission occurring through breast-feed­ ing (lifson 1988). the primary routes o f transmission are therefore by sexual contact with an infected person, parenteral exposure to infected blood or blood products and perinatally from an infected mot her to her child. prior to 1 989, there has been 11 0 documentation of h iv infection occurring as a result of participation in sports. how7ever, the theoretical possibility7 of h iv transmission through open bleeding wounds in contact sports has been recognized by sports physicians (alcena 1988, loveday 1989). the first case of possible h iv transmission as a result of sports participation w7as pub­ lished in 1 9 9 0 (torre et al 1990). this involved an italian soccer player in whom h iv seroconversion w7as documented weeks after a traumatic incident during a soccer match. during the soccer match the player col­ lided with another player w7ho w7as later documented as being h iv seropositive. both players sustained open bleeding w7ounds resulting in possible mixing of blood. there w7as no indication that the player may have been infected through any other route of hiv transmission. the authors concluded that this was the first case of 16 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) h iv transmission which occurred directly as a result of sports participation (torre et al 1990). although this case report has been criticized on epidemiological grotmds (goldsmith 1 992), it nevertheless has clear implications for the risk o f h iv transmission during sports participation. in particular, those sportspeople that participate in contact sports such as boxing, wrestling, rugby and soccer are potentially at risk. it must be emphasized that to date no cases of hiv transmission have been recorded in either the sporting or the non-sporting population through contact with saliva, social contact or sharing facilities such as living space, toilets, bathrooms, eating and cooking facilities (loveday 1989). it must also be borne in.mind that the risk of h iv infection in sportspeople is the same as that in the general population if there is a history o f engag­ ing in well established high risk behaviors for h iv transmission (table 1). table 1 : high risk behaviour for h i v transmission anal sexual intercourse with or without the use of a condom sexual intercourse wit h multiple partners or with one person who has sexual intercourse with multi­ ple partners (eg. prostitutes) vaginal or anal sexual intercourse with someone who uses intravenous drugs or engages in anal sex­ ual intercourse the sharing o f needles, razors, toothbrushes or any instrument that may cause bleeding (including mouthguards) sexual intercourse with an h iv infected person especially if a condom is not used the use o f drugs or excessive alcohol may result in participation in the above mentioned behavior patterns although there is documentation o f only' a single pos­ sible case o f h iv disease as a result o f sports participa­ tion in contact sports, there is a need to establish clear guidelines for the prevention o f htv transmission din ­ ing sports participation. as early as 1 9 8 9 the international sports m edicine federation (fim s), together with the world health organization, pub­ lished guidelines for the prevention of h iv transmis­ sion during contact sport (who position statement 1989). subsequently, other organizations such as the australian sports medicine federation (sheridan, 1 992), the american academy o f pediatrics (american academy o f pediatrics, 1 9 91), and m ost recently, the national football league in the usa (brown et al 1994) have published similar guidelines. in south africa, to date only the south african football medical association (safma) have published an official posi­ tion statement on h iv disease in sport. the question that is foremost in the minds of sports administrators and participants, is what is the risk of h iv transmission in sport. in answer to this, tliere are no epidemiological data available to date to calculate the risk of h iv transmission during sports participa­ tion. at best, a theoretical risk o f transmission in a sport can be calculated by7 considering the following variables (sheridan, 1992): the estimated carrier rate of h iv in the sports parthe estimated chance o f an open bleeding wound in a sports participant (incidence o f open bleeding woimds) the estimated chance of two players with open bleed­ ing woiuids making contact that could result in blood to abrasion or blood to mucous membrane exposure (incidence of physical contact between two partic­ ipants) (lie estimated chance o f transmission of the virus when infected blood makes contact with an open bleeding wound (estimated to be 0.3-0.5% which is similar to that calculated for a needlestick injury) i f all the above data are available for a particular sport, the estimated risk of h iv transmission can be calculat­ ed (table 2). at present, accurate data are only avail­ able for one sport, american football (calabrese 1993). in american football the risk o f h iv transmission in a game has been calculated as 0 .0 0 0 0 0 0 0 1 0 4 . this can be translated to approximately one player becoming infect­ ed per 10 0 million games. clearly, this is a very low risk and is probably the reason why there is no widespread documentation o f hiv infection in american football players. table 2: calculation o f the theoretical risk of h iv transmission in sport risk = seroprevalence o f h iv (%) x risk of open bleeding wound (%) x risk o f contact with a bleeding player (%) x 0 .0 3 * *: estimated to be similar to the risk o f seroconver­ sion after a needlestick injury ticipants (% participants that are h iv positive) however, it must be pointed out that the seropreva­ lence in american football players was estimated to be 0.5%, and that both the risk o f an open bleeding wound (0.9%) and the risk of contact between players (7.7%) were low. these estimates will differ between different populations (higher seroprevalence) and sports (higher risks o f bleeding and player contact). for instance, in a boxing light of 12 rounds, the risk o f an open bleeding wound is approximately 33%, and the risk of contact is probably 100%. the risk o f seroconversion after contact between two boxers may also be higher than that o f a needlestick injury for at least two reasons. blood may be forced into the wound by the nature o f the blow, and contact may be repetitive. finally, if the seroprevalence o f h iv in boxers is high, the risk of transmission in box ing may be much higher than that reported for american football. there is thus a need to obtain accu­ rate research data on the incidence and nature o f open bleeding wound injuries as well as the risk o f contact between play7ers if more accurate assessments on die risk of h iv transmission during sports are to be made. despite the lack of accurate scientific data, the pre­ vention of h iv disease in sportspeople has to be addressed by establishing clear guidelines for sports participants, administrators and medical personnel involved in sport. a number of practical recommenda­ tions can be made to decrease d ie risk o f h iv trans­ mission in sport. these are summarized in table 3. sports medicine march 1996 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table 3: guidelines for the prevention o f hiv transmission in sports a. general guidelines: t he following general guidelines are suggested to reduce the risk of transmission o f h iv in sport: in general the risk of hiv transmission as a result of sports participation is very low the risk is higher in contact sports where there is a risk of transmission through contamination of open lesions, wounds or mucous membranes o f a noil-infected individual with infected blood or blood products at present there is no risk o f transmission from saliva, sweat, tears, urine, respiratory droplets, hand-shakmg, swimming pool water, communal bath water, toilets, food or drinking water b. specific guidelines for sportspeople: the following are specific guidelines for the individual sportsperson to reduce the risk o f h iv transmission during sports: a sportsperson who engages in high risk behavior (table 1) is advised to seek medical attention regarding poss ^ r t ̂ s r a ^ w i l i i known h iv infection should seek medical and legal counselling before considering further participation in sport in order to assess risks to their own health as well as the theoretical risk of h iv trans­ mission to other sportspeople , . . . . , . sportspeople with known h iv infection should inform medical personnel of then condition if they sustain an open wound or skin lesions during sports participation so that these can be managed appropriately c. specific guidelines for sports administrators: sports administrators, including coaches and managers have special opportunities for meaningful education of sportspeople with respect to h iv disease. they should encourage sportspeople to seek medical counselling where appropriate. finally, they also have an important role in ensuring that adequate medical care is available for th en sportspeople. d. specific guidelines for medical personnel attending to sportspeople: guidelines for medical personnel in preventing h iv disease in sportspeople are: in general the guidelines for management o f hiv-positive patients that have been published in a policy state­ ment by the college of medicine of south africa can be applied by medical persomiel that attend to sports­ people with suspected h iv disease (policy statement, 1991) . , , r ,, . , , all open skin lesions sustained during sports participation shoidd be treated appropriately before allowing the sportsperson to return to the playing field the following treatment of open skin lesions is recommended: immediate cleaning o f the wound with a suitable antiseptic such as hypochloride (bleach, milton), 4/o gluteraldehyde (cidex), organic iodines or 70% alcohol (ethyl alcohol, isopropyl alcohol) the open wound should be covered securely so that there is no risk o f exposure to blood or blood products prior to returning to the playing field it is recommended that all first aiders and medical persomiel attending to sportspeople with open wound lesions wear protective gloves to decrease the risk o f h iv transmission to themselves and other sportspersons 18 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the effects o f hiv infection on exercise performance the h iv epidemic will inevitably affect physically active people. this would include people that are phys­ ically active in sports (recreational or competitive) as well as manual laborers. two o f the questions that will arise as a result o f h iv infection in physically active individuals are i) whether h iv disease affects the indi­ viduals ability to perform physical work and ii) whether regular physical work has a beneficial or perhaps a detrimental effect on the outcome o f the disease? these two questions have important implications for the sportsperson as well as advice regarding the occu­ pation o f an infected individual. there is very7 little information available in the m ed­ ical literature on the effect of iiiv infection on the abil­ ity to perform physical work. indeed to date only a few studies have addressed this issue, hi one study exer­ cise performance was investigated in 32 patients with a clinical diagnosis o f a id s (johnson et al 1 9 8 9 ). patients with documented aid s and complaining of dyspnea on exertion were enrolled in the study and their exercise performance was compared to a group of age, height and weight matched normals. h iv infected patients with evidence o f pulmonary infection, athero­ sclerotic heart disease, asthma, pre-existing pulmonary disease or other significant complicating medical disor­ ders were excluded from the study the exercise test to which patients and control sub­ jects were subjected consisted of an incremental exer­ cise test to exhaustion during which cardiorespiratory variables were measured. arterial oxygen saturation was measured by finger oximetry. spirometry was done before and immediately after the exercise test. the results of this study were that the patients with docu­ mented a id s exercised to a significantly lower work­ load than controls, had a lower maximum oxygen uptake (vo2 max) than controls (not statistically signif­ icant), had similar maximal heart rates as controls, had a lower “ ventilatory anaerobic threshold” than controls, and did not have bronchospasm post-exercise. nine subjects achieved an oxygen consumption (vo2) less than 81% o f the predicted whereas none o f the con­ trols exhibited this. the authors concluded that some aid s patients have impaired exercise performance and this was attributed to a central (cardiac) limitation. the possibility7 o f a direct effect of the h iv infection or its complications on muscle function was not considered. in another study exercise testing was included as part of a clinical trial evaluating the effectiveness of cor­ ticosteroids on pneumocystis carinii pneumonia in aid s patients (montaner et al 1990). in this study aid s patients with pneumocystis pneumonia were ran­ domly allocated to either an experimental (receiving corticosteroids) or a control (receiving placebo) group and then monitored for 4 weeks. a maximal incremen­ tal exercise test was performed on days 0, 3, 7, 14 and 30. effort tolerance was very poor in both groups on day 0. after treatment the exercise tolerance improved sev­ enfold in the treatment group whereas it remained the same in the control group. this positive effect was attributed to the prevention of early clinical deteriora­ tion by the administration of corticosteroids in the treatment group. it is obvious that this study was not primarily aimed at investigating effort tolerance in these patients. however, the results do indicate that table 4: summary of clinical trials: htv infection and exercise patients exercise program m e characteristics outcome (exercise group) reference frequency intensity duration period type h i v +ve (n=21) 2/week ? 1 hr 8 wks various sports games reduced anxiety/ depression cd4 count cd4-cd8 ratio schlenzig et al, 1989 asymptomatic h iv +ve (n=16) 3/week 70-80% o f h r max 4 5 min 10 wks cycle ergometer internal type training reduced anxiety/ depression non significant decline in nk trend for increase in cd4 count laperriere et al, 1991 h i v +ve (n=37) 3/week 60-80% 'of h r reserve (20 miris) 1 hr 12 wks cycle ergometer strength/ flexibility training improved muscle strength and endurance no change in lymphocyte rigsby et al,1992 sports medicine march 1996 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physical work is severely impaired in a id s patients with associated pneumocystis infection and that this can be improved by appropriate therapy. the effects of regular exercise training on patients who were seropositive for the hiv but who were other­ wise asymptomatic, have also been documented. in one study 4 5 male volunteers who were allocated randomly' to an exercise and a counselling group (rigsby et al, 1992). the groups were well matched according to m od­ ified walter reed criteria. the patients in the training group underwent exercise training consisting o f cycling, weight-training and flexibility exercises for 12 weeks. exercise testing and immunological parameters were assessed before and after the training period. one of the significant findings o f the study was that the trained group showed evidence of adaptation to exer­ cise. this study therefore indicated that 12 weeks exer­ cise training in h iv seropositive patients can result in improved physical work capacity. in summary, patients with aid s appear to have impaired physical work capacity, the precise mecha­ nism of which is not clear. asymptomatic patients with h iv disease appear to respond well to exercise training. the effects of regular physical activity on the out­ come o f hiv infection it is well recognized that an acute bout o f physical exer­ cise, as well as exercise training, has significant but variable effects on a number of immunological parame­ ters (keast et al, 1988, mccarthy et al, 1988, nehlsen cannarella et al, 1 991, nieman et al 1 989, nieman et al 1991, oshida et al, 1988, ricken et al, 1990). an acute bout of exercise will result in a leucocytosis, the magni­ tude o f which is related to the intensity o f exercise, the duration o f exercise and the state of exercise training o f the athlete (mccarthy et al, 1988). the nature o f the leucocytosis is variable and can either be a predominant neutrophilia or a predominant lymphocytosis. furthermore, changes in lymphocyte subsets can also occur in response to an acute bout of exercise (oshida et al, 1988). it has been documented that there is an increase in the absolute cell numbers o f all lymphocyte subsets, but that the increase is greater in b cells com­ pared to t cell subsets; thereby decreasing the t cell to b cell ratio (keast et al, 1 988, mccarthy et al, 1988). it has also been demonstrated that a greater increase occurs in t 8 compared to t 4 cells during exercise; thereby decreasing the t 4 /t 8 ratio (mccarthy et al, 1988). hi addition, total l y m p h o c y t e proliferation to antigens and mitogens is typically reduced in response to exercise (keast et al, 1988). the response of t lymphocytes to an acute bout of exercise has clear implications for individuals infected by the hiv. o f particular importance is the effect of exercise and exercise training on t cell counts and the c d 4 /c d 8 ratio. to date there are no published studies on the possible association between a programme of regular physical activity and the long term clinical out­ come of h iv infection. however, it has been suggested by long term aid s sufferers that regular exercise con­ tributed to their longevity (solomon et al 1987). in recent years, several groups of investigators have been concerned with and have published data on the effects of exercise on the clinical course of h iv infected individuals. the results o f three well controlled ran­ domized clinical trials on the influence of regular exer­ cise training on immunological and psychological para­ meters in h iv positive patients are presented in table 4. hi one of the earliest reports from the university of miami, the beneficial effects o f regular exercise training on c d 4 cells o f hiv-infected individuals has been doc­ umented. hi tliis stud}', 10 weeks of exercise training at moderate intensity (< 80% o f maximal heart rate), for 4 5 minutes three times a week resulted in an increase in c d 4 cells (laperriere, 1 9 91). in another aspect o f the stud}', high risk individuals who were regular exer­ cisers, showed less anxiety and depression after receiv­ ing the news that they were h iv seropositive. exercise appeared to provide a “buffer” to the psychological sequelae of a powerful acute stressor in these patients. the findings from the group at the university of miami have the following possible practical applications: i) that exercise can play a beneficial role in the pre-hiv test counselling of potentially infected patients, and ii) that regular, moderate intensity exercise can play a role in the management of early, asymptomatic individuals with h iv infection (calabrese et al 1993). recently, specific recommendations on the role o f regular exer­ cise in the management o f patients with h iv disease have been made. these are summarized hi table 5. summary regular participation in physical activity is advocated as an important preventative health measure. however, the global pandemic of h iv infection is likely to influ­ ence physically active individuals. the association between h iv infection and physical activity therefore requires attention. in this review the risk of h iv trans­ mission during sport and physical activity, the effects of table 5: recommendations for exercise in patients with hiv infection a. general before initiating any type o f exercise-training, all iilv infected individuals regardless of age or stage of disease should: have a complete physical examination discuss exercise plans with a physician or exercise specialist comply with acsm testing and prescription guidelines.' b. healthy asymptomatic hiv seropositive unrestricted exercise activity continue competition avoid overtraining c. aids-related complex continue exercise training on symptom listed basis avoid strenuous exercise reduce or curtail exercise during acute illness. d. diagnosed aids remain physically active continue exercise training on symptom limited basis avoid strenuous exercise reduce or curtail exercise during acute illness 20 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) h i v in fe ctio n on e x e r c is e p e rfo rm a n ce , and th e e ffe c ts o f regu lar p h y sica l activity on th e o u tco m e o f h iv in fection w as d is cu s s e d . references: alcena v: boxing and the transmission o f iiiv new york slate j med 1988; july: 392. american a cadem y o f pediatrics: human immunodeficiency virus i acquired immunodeficiency syndrome (a id s) virusj in the athletic setting. pediatrics 1991; 8 8 (3 ) 640-641. astrand po: why exercise? med sci sports exerc 1992; 24 640-641. australian sports medicine federation: infectious disease policy. sports medicine news (suppl to sport health) 1992; 1 0 (1 ): 8-9. brown jr, phillips ry, brown cl, et al: hiv/aids poli­ cies and sports; the national football league. med sci sports exerc 1994; 2 6 (4 ) : 403-407. calabrese l, laperriere a : human immunodeficiency virus infection, exercise and athletics. sports med 1993a; 1 5 (1 ): 613. calabrese l: h iv infection, exercise and athletics. invited paper at the 40th annual meeting o f the american college o f sports medicine, june 2-5, 1993. friediand gh, klein rs: transmission o f the human immunodeficiency virus. new engl j med 1987; 317: 1125 1135. goldsmith mf: when sports and iiiv share the bill, smart money goes on common sense medical news and perspectives. jama 1992; 277: 10-13. human sciences research council on sports participation in south africa 1982 ijsselmuiden cb, steinberg mh, padayachee gn et al: a id s and south africa towards a comprehensive strategy. part 1. the workl-wicle experience. samj 1988a, 73: 455-460. johnson ,ie, anders gt, blanton hm et al: exercise dys­ function in patients seropositive for the human immunodeficien­ cy virus. american review o f respiratory disease 1990; 141: 618-622. keast, d, cameron k, morton a r : exercise and the immune response. sports med 1988; 5: 248-267. laperriere a , fletcher ma, klimcis n, et al: aerobic exer cise training in an aids risk group. int j sports med 1991; 12: s53-s57. laperriere a , o ’hearn p, ironson g, et al: exercise and immune function in healthy h iv antibody negative and positive gay males. proc ninth ann scientific sessions o f soc behavioral med, boston, march 27-30, pp 28, 1988. lifson a r : d o alternate modes for transmission o f human immunodeficiency virus exist? a review. jam a 1988; 259 (9 ) ■ 1353-1356. loveday c: iiiv disease in sport. medicine, sport and the law chapter 5 pp 81-86. 1989. mccarthy da, dale mm: the leucocytosis o f exercise. a review and model. sports med 1988; 6: 333-363. mmwr: pneumocystis pneumonia los angeles mmwr 1981a; 30: 250-252. mmwr: kaposi s sarcoma and pneumocystis pneumonia among homosexual men new york city and california mmwr 1981b; 30: 505-308. montanerjsg, lawson lm, levitt n el al: corticosteroids pre­ vent early deterioration in patients with moderately severe pneit mocystis carinii pneumonia and the acquired immunodeficiency syndrome (aid s). annals o f internal medicine 1990; 113-14-20 moodie jw: serology o f aids. s/1 j o f continuing medical education 1988b; 6: 58-67. moodie jw: the aids epidemic. .s/1 j o f continuing medical education 1988a; 6: 37-46. nehlsen-cannaretla sl, nieman dc, balk-lamberton aj, et al: the effects of moderate exercise training on immune response. med sci sports exerc 1991; 2 3 ( 1 ) : 64-70. nieman dc, berk ls, simpson-westerherg m, et al: effects o f long-endurance running on immune system parameters and lym­ phocyte function in experienced marathoners. int j sports med 1989; 1 0 (5 ) : 317-323. nieman dc, nehlsen-cannarella sl, donohue km, et al: the effects of acute moderate exercise on leukocyte and lymphocyte subpopulations. med sci sports exerc 1991; 2 3 ( 5 ) : 578-585. oshida y, yamanouchi k, hayamizu s, el al: effect o f acute physical exercise on lymphocyte subpopulations in trained and untrained subjects. int j sports med 1988; 9 ( 2 ( : 137-140. policy statement from the college o f medicine o f south africa. management o f hiv-positive patients. samj 1991; 79 688-690. position statement: world health organization (w h o ), world federation of sports medicine (fim s): consensus state­ ment on a id s and sports. br j sports med 1989; 23 ( 2 ) : 132. ras gj, simpson iw, anderson r, et al: acquired immun­ odeficiency syndrome: a. report o f two south african cases. samj 1983; 64: 140-142. ricken kii, rieder t, ilauck g, et al: changes in lymphocyte subpopulations after prolonged exercise. int j sports med 1990' 1 1 (2 ): 132-135. schall r : on the maximum size of the a id s epidemic among the heterosexual black population in south africa. samj 1990 78: 507-510. schoub bd, smith .1 a. johnson s, et al: considerations on the further expansion o f the aids epidemic in south africa: 1990. samj 1990; 77: 613-618. sher r: a id s clinical diagnosis and treatment. .s71 j ofcme 1988; 6: 31-36. sheridan jw: blood-borne infections in sport. sports medicine news (supplement to sports health) 1992; 1 0 (1 ): 2-7. solomon gf, tomoshok la: a pscychoneuroimmunologic perspective on aids research: questions, preliminary findings and suggestions. j appl soc psychology 1987; 17: 286-308. torre d, sampietro c, ferraro g et al: transmission ofh iv 1 infection via sports injury. lancet 1990; 335: 1105. ziegler jb, cooper da, johnson ro, et al: post natal trans­ mission o f aids associated retrovirus from mother to infant. lancet 1985; i; 896-898. [f] sports medicine march 1996 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) readership survey if yo u wish to continue receivin g this jou rn al, free of ch a rg e , p le a s e fill in the form b elow and return it to: glenbarr publishers cc private bag x i 4 parklands 2121 name:............................................................................................................................... address:........................................................................................................................... code:.............. speciality 22 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) vitamin c as effective as combinations of anti-oxidant nutrients in reducing symptoms of upper respiratory tract infection in ultramarathon runners. peters, em* m.sc.(med) goetzsche, jm* b. physjjd joseph, le* m.ed. noakes, td**(m bbch, md, facsm) abstract the effect o f anti-oxidant supplementation on the inci­ dence of symptoms of upper-respiratory-tract infection (urti) was determined during the fortnight following the 1 9 9 3 com rades marathon (90k m ). runners (n =178) and sedentary matched controls (n=162) were randomly divided into groups receiving 500m g vit c (c; n=86), 500m g vit c and 4 0 0 1u vit e (ce; n =90) or 300iu vit e, 300m g vit c and 18m g beta carotene (ceb; n=73) or placebo (p; n =93) daily for 21 days prior to participation in the ultramarathon. total pre-race dietary vitamin and mineral intakes and post-race self reported urti symptoms were recorded in all subjects (n=340). the incidence o f the urti symptoms in p run­ ners (40.4% ) was significantly higher (p<0.05) than that in c (15,9% ) and ceb (20,0% ) runners, and also greater than that in matched, non-running controls receiving placebo (24,4% ). the group o f runners reporting the lowest incidence of urti symptoms during the post­ race period, had the lowest mean age and the highest (i) total mean daily vit c intake (1 0 0 4 mg); (ii) pre-race training status and (iii) percentage of black runners. this study suggests that vitamin c alone is as effec­ tive as combinations o f beta carotene, vitamin e and vitamin c in reducing the incidence of post-race urti symptoms and that age, training status and genetic make-up also may influence the susceptibility to the development of urti symptoms in ultramarathon runners. key words: anti-oxidant vitamins, upper respiratory tract infections, ultramarathon runners. * division of physical education, university of the witwatersrand, johannesburg, south africa. * * mrc bioenergetics of exercise research unit in the sport science institute of south africa, medical school, university of cape town, south africa. correspondence: edith peters division of physical education, university o f the witwatersrand, johannesburs, 2001, south africa. tel: (011) 7 1 6 -5 7 1 8 introduction two separate epidemiological surveys performed on ultradistance runners1 ~ have reported an increased inci­ dence of symptoms of upper respirator}' tract (urti) following participation in ultrainarathon events. a sub­ sequent study5 found that daily administration of 600m g vitamin c for three weeks prior to the 90km comrades marathon, resulted in a significantly lower (p<0.05) incidence of symptoms o f infection in runners during the fortnight after the race, compared to runners ingesting placebo. this was attributed to the anti-oxi­ dant properties of vitamin c, which suggests that ath­ letes participating in prolonged exercise have an increased daily vitamin c requirement. ' . evidence from more recent studies45 is that the anti­ oxidant nutrients may be more effective when used in combination. the aim of this study was therefore to compare the efficacy o f supplementation with combina­ tions of vitamin e, vitamin c and beta carotene and vitamin c alone in reducing the incidence o f post race urti in ultra marathon runners. method the protocol was approved by the committee for research on human subjects o f the university o f the witwatersrand. two hundred and twenty entrants for the 1993 comrades marathon volunteered to partici­ pate in the study. each runner was matched (n=220) with a control of similar age who resided with the run­ ner, but did not participate in running regularly. a dou­ ble-blind, placebo-controlled study design was used in which the runners, in addition to their matched, non running controls, were randomly divided into four groups. each group received either anti-oxidant supple­ ments or placebos for three weeks prior to the race. the pre-race training status, state of health and dietary vit­ amin and mineral intake o f athletes and their age matched controls was recorded by means of a question­ naire which each runner and control subject completed prior to the race. demographic data including running distance per week, average running speed, number of weeks spent training and the number o f other ultrama­ rathons in which the athlete had recently participated were also recorded, h i addition, the pre-race incidence of self-reported symptoms o f urti was documented. runners with a history7of sinusitis, hay-fever or both were excluded. each runner and matched control (n=55) was required to take three tablets o f similar appearance daily. these contained either 500m g vit c (c), 500m g vit c & 400iu vit e (ce), 300m g vit c & 300iu vit e, 18 mg beta sports medicine march 1996 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) carotene (ceb) or lactose as placebo (p). the total daily vitamin a, c and e intakes including that derived from any additional vitamin and mineral used by the athlete of all subjects was determined by using the dietary manager computer programme (program management, randburg, south africa). for the purpose o f this study, the total vitamin a, c & e intake of each subject was thus calculated from the sum of the (i) daily dietary intake, (ii) additional supple­ ments used and (iii) the anti-oxidant supplements given to the subjects. two weeks after the race all runners and controls who had originally volunteered to participate in the study were telephonically interviewed and questioned regarding: (i) whether the prescription of supplements had been adhered to or not; (ii) the race distance cov­ ered and the time taken by each athlete to complete this distance; (iii) the incidence and duration of symp­ toms of urti. the number and duration o f self-report­ ed symptoms including sneezing, running nose, sore throat, cough and fever were documented. all reports of trivial symptoms were excluded by including in the final analysis only reports of single urti symptoms which lasted >1 (lay or a combination o f at least 2 urti symp­ toms each o f which lasted < i day. the training status ratio of each runner was calculat­ ed from the following formula: weekly training distance (km) • no o) weeks spent in training average speed at which those kilometres were covered as in our previous study®, runners who reported a ratio of > 4 5 0 fell into the high-training status category, whereas those with a ratio < 3 0 0 were classified in the low training status category. statistics a chi-square statistic was used to establish whether the incidence o f symptoms o f urti was significantly differ­ ent between the four groups o f runners and controls. multivariate analysis of variance and several one-way analyses of variance were used to analyze the signifi­ cance o f the difference between the four groups in terms of age, vitamin c, e and beta carotene intake and training status ratio. for all statistical analyses the statgraphics and excel computer software programs were used and the level of significance were set at 0.0 5 . results o f the initial 22 0 runners and matched controls, 178 runners (23 female; 155 male) and 162 (116 female ; 4 6 male) controls compiled fully with the requirements of the study. reasons for exclusion from the study includ­ ed a prev ious history o f allergic rhinitis, failure to take the prescribed medications, failure to complete at least 6 0 km of the race and inability to establish contact with the subjects after the race. the size, gender distribution and mean age o f the 4 groups o f runners and their matched controls is given in table 1. among the runners who ranged in age from 19 to 6 5 years, 4 6 were < 30 y old, 119 were aged between 31 and 50 y and 13 were > 5 0 y in age. although the two groups with the highest incidence o f reports o f urti possessed the highest mean age, this was not signifi­ cantly different from the mean age o f the groups with lower incidence of infection (p>0.05). table 1: the size, gender distribution and age (+ /sd) o f the 4 study groups (n=340) mean experimental runners controls group (n 178) (n = 162) n age n age m f (years) m f (years) group c 44 34,3 41 33,1 36 8 (5,2) 11 30 (9,5) group ce 47 37,6 43 33,7 41 6 (8,4) 11 32 (9,2) group ceb 40 35,1 33 29,7 36 4 • (10,0) 8 25 (11,9) group p 47 39,2 45 32,8 42 5 (9,5) 16 29 (11,8) the total mean vitamin a, e and c intakes of the run­ ners in each o f the four groups is shown in table 2. the highest total mean intake of vitamin c was reported in group c, whereas the p group reported a mean intake of 585m g o f vitamin c. groups ce & ceb also reported high mean intakes o f this vitamin. group ceb was the only group with a vitamin a intake which exceeded the rd a for sedentary individuals'', whereas group ceb was the only group which exceeded the rda0 of vitamin e for sedentary7 individuals. the group with the lowest incidence of infection (c) reported a total mean vitamin c intake of 1004m g. t a b le 2: the mean vitamin a , c and e intakes o f the runners ( n=l 78) in the 4 groups. group c group ce group ceb group p food vit a (iu) 3170 4405 3915 3110 sources vit c (mg) 72 93 95 80 vit e (iu) 25 22 26 18 additional vit a (iu) 1446 1737 2348 2992 supplements vit c (mg) 432 305 271 505 vit e (iu) 12 22 8 43 anti-oxidant vit a (iu) . 30 000 supplements vit c (mg) 500 500 300 provided vit e (iu) 400 300 total vit a (iu) 4616 6142 36 263 6102 vit c (mg) 1004 893 665 585 vit e (iu) 37 444 334 61 24 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the incidence of symptoms o f urti in the runners and controls are given in figure 1. the difference between the incidence of symptoms o f infection in die runners ingesting placebo (40.4% ) and their sedentary, matched controls (2 4 .4 % ) was not significantly different (x 2= 1 .9 9 ; p = 0.16). the lowest incidence of infection amongst the runners (15.9% ) was reported in group c. this was significantly different (x 2= 5 .5 4 ; p < 0 .0 5 ) from the incidence o f urti symptoms in group p a 20% inci­ dence o f infection was reported hi group ceb. the inci­ dence o f symptoms of urti in group ce was also sig­ nificantly lower than in group p (x 2 = 6 .2 4 ; p > 0.05). the incidence o f symptoms o f infection in group ce (25.6%>) was not significantly different (p > 0 .0 5 ) than the incidence in group p (40.4% ). the incidence, nature and mean duration o f the symptoms o f urti among nmners and control subjects is presented in table 3. the m ost common urti symp­ toms reported by runners in the 4 groups were nasal (n = 35). included in this category were reports of running noses and sneezing. symptoms lasting more than 7 days occurred in 20 cases (nasal), 13 cases (sore throat) and 12 cases (coughing). twelve o f the runners reported fever in conjunction with their urti symptoms. only 24,2% o f the reported runners symptoms lasting 1-3 days. the mean duration o f symptoms in die runners was not significantly different from the mean duration o f symptoms in the control subjects (p > 0.0 5 ). although the mean duration of symptoms was higher in runners on placebo than in runners who received the different combinations o f anti-oxidants, this difference was not statistically significant (p > 0.05). table 3: incidence, nature and duration o f post­ race symptoms of urti among runners and control subjects. experimental group 0/o mean (± sd) n symptomatic trarning status ratio group c group ce group ceb group p 42 20,2* 311 (±150)** 47 25.8 274 (±127) 40 16,7* 328 (±166)** 47 40,4 236 (±111) * p < 0 .0 5 vs group p ** p <0.01 vs group p the incidence o f infection in the low, medium and high training status groups is shown in figure 2. those n m ­ ners who reported a low pre-race training status (<250) group reported the highest incidence o f infection symp­ toms. this finding was confirmed when the incidence o f post-race urti symptoms was related to the mean training status o f die 4 groups o f nmners (table 4). the two groups with an incidence o f urti symptoms of more than 25%, reported the lowest mean training sta­ tus. the difference between the training status of groups c and ceb (possessing the lowest incidence of infection) and groups ce and p (possessing the highest figure 1: incidence o f symptoms o f urti in runners (n = 178) and controls (n post race period. 162) during the 14 day runners (n = 178) (x* = 8,20; p < 0,05) 60 50 (0 o ■<d. 5 * 40 cn o 30 o 20 10 60 5040 30 20 10 15.9%* i 25.5% 1 20.0% 40.4% controls (n = 162) (xz = 3,01; p > 0,05) 12.2% i 23.3% i 15.1% 24.4% group c group ce group ceb group p group c group ce group ceb group p symptomatic asymptomatic * significantly different from group p (p<0,05) sports medicine march 1996 25 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) figure 2: the incidence o f post-race urti symptoms in low, medium and high training status groups (n=176) n u m b er 50 — o f s u b je c ts 25 — 31,1% \ \ \ \ v 24,6% \ \ \ | \ \ ] sym ptom atic □ n on-sym ptom atlc x2 = 2,21 p > 0,05 17,2%. <300 300-450 >450 low med high training status ratio incidence of infection) was highly significant (p > 0.01). when the incidence o f urti symptoms were related to weekly training distance completed in preparation for the race, this trend was confirmed. once again, the run­ ners who had done the least pre-race training, reported the highest incidence of urti symptoms. a total o f 16 black runners participated in the study. none of these athletes reported symptoms of urti. when excluding the black runners from their respective groups, the percentage incidence o f infection symptoms in the respective groups was 2 5 ,7(c); 4 1 ,3(f); 26,7(c e) and 2 3 (ceb). the difference between the three groups receiving additional anti-oxidant supplementation was not significant (p > 0.0 5 ). despite a substantial differ­ ence in percentage incidence in the placebo group and the groups receiving anti-oxidant supplementation, this difference was no longer significant ( p > 0.05). no relationship between running time and incidence o f urti symptoms in the four groups was found in this study. although the incidence was highest (35,5%) in those runners who took >10hrs to complete the race, this incidence was not significantly greater than the incidence in groups taking 7 -8 hrs (23.5% ) and 8 -9 hrs (27,8% ) to finish the race. discussion the data obtained in this study confirms our previous findings12 8,7 o f a greater incidence o f post-race symp­ tom s of infection in ultramarathon runners compared to sedentary controls (figure 2). the comparatively lower general incidence of symptoms in this study than in our previous study1 must be seen in the light of the fact that (i) in this study, reports o f symptoms lasting one day or only part thereof were not included in the final calcula­ tion and (ii) prevailing virological or bacteriological counts may have varied greatly at the time that these two separate studies were undertaken. this study confirms previous findings3 that daily intake o f an excess of l g of vit c is effective in lowering the incidence of symptoms of urti during the post­ race period. although the incidence o f symptoms of urti was substantially lower in all three groups o f run­ ners receiving anti-oxidant supplementation than in the group o f runners receiving placebos, no correlation was obtained between the total amount of anti-oxidant nutrients ingested and the incidence o f symptoms of urti. rather, it was the group with the highest total daily intake of vit c which had the lowest incidence o f urti symptoms. several factors could account for this. table 4: the mean training status ratio and incidence o f post race urti symptoms in the 4 groups of runners (n=176) __________ _______ ____________ experimental group p ost race symptoms nasal symptoms sore throat cough fever and urt symptoms total symptomatic * * mean duration o f symptoms a : runners group c group ce group ceb group p (n=44) (n=47) (n=40) (n=47) 11 duration n duration n duration n duration 5,3 10 5,8 5,8 9,0 9 4,7 2 3,0 2 . 12 7,0 1,8 7 5 4 4 8 7,6 14 5,8 12 4,5 4,: 4,3 8 5 19 6 i 7,8 6,4 5,8 5,6 b : controls group c group ce group ceb group p (n=41) (n=43) (n=33) (n=45) n duration 11 duration 11 duration n duration 7,0 7,8 9.6 14.6 8 22,8 8 9,3 8 11,1 2 11 9,4 17,5 15,2 0 3 1 6 5 3.2 11 7,8 1.3 8 8,1 77,0 0,0 4 11 2,3 10,3 2,0 6,9 nasal symptoms include runny nose and sneezing. ** no. of persons in the group who presented with 1 or more symptoms lastmg_ 1 day or 2 more symptoms lasting < 1 day duration = mean no. of days 26 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) vitamin c is regarded as a first line anti-oxidant in the defence against phagocytederived reactive oxi­ dants8010. these immunosuppressive free radicals are known to be autotoxic, causing inhibition o f chemo taxis, phagocytosis, the proliferation o f t-lymphocytes and b -lymphocytes as well as the cytotoxic activity o f natural killer cells 111213. evidence is mounting in favour o f vitamin cmediated neutralization o f these reactive oxidants8910. the relatively smaller protective effect of vitamin e and beta carotene supplementation may, be partially attributable to the slow elevation in plasma vitamin e and beta carotene levels15 and the fact that a 21 day supplementation period is too short to elevate plasma levels to reach protective levels. secondly, variance in age14, training status15, environmental training condi­ tions'", and genetic make-up between the groups stud­ ied, may have obscured the effect of the other anti-oxi­ dant nutrients. a s in our previous study3, age does not appear to have played a significant role in the risk o f infection. training status, however, appeared to be an important factor. the highest incidence of symptoms o f urti was found in those runners who fell into the low training status category (figure 2). further confirmation o f a possible beneficial effect o f training is found when examining the mean training status o f the four groups. it was found that the two groups possessing the high­ est training status had the lowest incidences o f infec­ tion symptoms (table 4). these findings were further supported when the incidence o f urti symptoms was analysed as a function o f weekly training distance. two factors m ight support, this finding. first, endurance training results in a lower catecholamine levels at a given exercise workload. this is potentially important as catecholamines affect free radical produc­ tion16. second, endurance training increases concentra­ tions o f endogenous antioxidant enzymes in skeletal muscle15. that endurance training exerts a protective effect on oxidative stress thus warrants further investi­ gation in humans. the finding that black runners who participated in this study did not develop infection symptoms, also requires further investigation. this difference might be explained by chance; socio-economic or hereditary fac­ tors may also have played a role. to conclude, the findings o f this study appear to indicate that large intakes o f vitamin c alone olooomg) are more effective than combinations of vitamin e, vitamin c and beta carotene in lowering the incidence of urti in ultradistance runners. this study, however, also indicates that besides vitamin c inges­ tion, training load and ethnic background, are impor­ tant variables which may influence the susceptibility to infection in ultramarathon runners. references 1. peters em. ultramarathon running fails to increase sus­ ceptibility o f ultramarathon runners to infections. s. afr. j. sports. med. 1990;5:4-8. 2. peters em, bateman ed. ultramarathon running and upper respiratory tract infections. s. afr. med. j. 1983;64:582 584, 3. peters em, goetzske jm, grobbelaar b, noakes td : vitamin c supplementation reduces the incidence o f post-race symptoms o f upper respiratory tract infections in ultradistance runners. a m j clin nutr, 1993:57:170-174. 4. packer je, slater tf, wilson ri.. direct observation o f a free radical interaction between vitamin e. and vitamin c nature. 1979;278:737-738. 5. sharma mk, buettner gr. interaction o f vitamin c and vitamin e during free radical stress in plasm a: an esr study. free rad biol & med 1993;14:649-653. 6. committee on dietary allowances, food and nutrition board, national research council. recommended dietary allowances. 10th edition, washington dc : national academic press, 1989. 7. peters em. cambell a , pawley l. vitamin a fails to increase resistance to upper respiratory infection in distance runners. s. afr. j. sports med. 1992;7:3-7. 8. bendich a , machlin lj. burton gw, wayner ddm. the anti-oxidant role o f vitamin c. adv free radical biol med. 1986;2:419-444. irt'i b, england l, am es bn. a scorbate is an outstanding anti-oxidant in human blood plasma. proc nat acad sci 1989;86:6377-6381. 10. anderson r, smit mj, joone gk, van staden am. vitamin c and cellular immune functions: protection against hypochlorus dehydrogenase and atp generation in human leukocytes as a possible mechanism o f ascorbate immunostimu lation. a nn n.y. acad. sci. 1982;587:34-48. 11. anderson r. phagocyte-derived reactive oxidants as medi­ ators o f inflammation-related tissue damaqe. s. afr j sri 1991;87:594-596. 12. babior bm. oxidants from phagocytes: agents o f defence and destruction. blood 1984;64:959-964. 13. herbaczynska-cedro k, wartanowicz m, panceczenko k resowska b, cedro k, klosiewicz-wasek b, wasek w: inhibitory effect of vitamins c and e on the free radical produc­ tion in human polymorphonuclear leukocytes. europ j clin invest. 1994;24:316-319. 14. ji ii/, mitchell ew, thomas dp. the effect o f exercise train­ ing on anti-oxidant and metabolic function in senescent rat skeletal muscle. gerontology. 1991;37:317-325. 15. machlin u , bendich a : free radical tissue damage: pro tective r°t(‘ ° f anti-oxidant nutrients fasebj. 1981;51:44116. fridowich i, freeman b. anti-oxidant defence in the lunq ann rev physiol 1986;48:693-792. 17. weiss sj. tissue destruction by neutrophils. new enal j med 1989;320:365-376. 18. viru a . hormones in muscular activity. boca raton fi : crc press, 1985. ' r~i sports medicine march 1996 27 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) south african journal o f sports medicine instructions for authors material submitted for publication in the sajsm is accepted on condition that it has not been published elsewhere. the management reserves the copyright of the material pub­ lished. all authors must give consent to publication, and the sajsm does not hold itself responsible for statements made by contributors. short items are more likely to appeal to our readers, and therefore to be accepted for publication, than very long ones. original articles of 3 000 words or less, with up to six tables or illustrations, should normally report observations or research of relevance to sports medicine or related area. short reports of 1 000 words or less, with one table or illus­ tration and no more than five references, include case reports, side-effects of drugs and brief or negative research findings. review articles, except those written by invitation, will not be accepted. authors may request that an article be considered for rapid publication; such articles should be of unusual importance. letters to the editor intended for the correspondence col­ umn should be marked “for publication” . letters longer than 400 words maybe returned for shortening, and only one illus­ tration or table will be permitted. manuscript preparation 1. copies should be neatly typewritten, with double spacing and wide margins. word processors may be used, provid­ ed the typeface is clear and legible, and the perforated margins have been removed. the manuscript must be submitted in triplicate and include the original; carbon or photocopies alone are not acceptable. a further copy of the manuscript should be retained by the author. 2. each article should be accompanied by a structured abstract consisting of the following sections: objectives, design, setting, subject, outcome measures, results and conclusions. the abstract should not exceed 250 words (50 w'ords for short reports). 3. refer to articles in recent issues of the samj for guid­ ance on the presentation of headings and subheadings. 4. all abbreviations should be spelt out w h e n first used in the text and thereafter used consistently. 5. scientific measurements should be expressed in si units throughout, with two exceptions: blood pressure should be given in mmhg and haemoglobin values in g/dl. 6. if in doubt, refer to “uniform requirements for manu­ scripts submitted to biomedical journals (br med j 1991; 302: 338-341). illustrations 1. figures consist of all material which cannot be set in type, such as photographs and line drawings. 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consult the list of journals indexed in index medicus for these details. names and initials of all authors should be given unless there are more than six, in. which case the first six names should be given fol­ lowed by “et al”. first and last page numbers should be given. journal references should appear thus: a. peter s. acute hamstring injuries. am j sports med 1994; 12(7): 395-400. book references should be set out as follows: a. williams g. textbook of sports medicine. 2nd edition: buttenvorth, 1989: 101-104. b. vandermere p, russel p biomechanics of the hip joint. in: nordien pe. jeffcoat a, eds, clinical biomechanics. philadelphia: wb saunders, 1990: 472-479. 4. “unpublished observations” and “personal communica­ tions” may be cited in the text, but not in the reference list. manuscripts accepted but not yet published can be included as references followed by “(in press)” . galley proofs will be forwarded to the author in good time before publication. proofs not returned within 48 hours will be regarded as approved. bear in mind that alterations to typeset articles are costly and may be charged to the authors. change of address. the editorial department should be notified of any address changes so that proofs and invoices may be mailed without delay. all manuscripts and correspondence should be addressed to: the editor, south african journal of sports medicine, po box 115, newlands,7725. 28 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a social cognitive perspective on promotive and preventive health behaviour in post-apartheid south africa i miller abstract non-communicable diseases or chronic diseases of lifestyle are on the increase amongst all south african population groups. there are, however, disparities in the health profile of black and white communities which can be attributed to the discriminatory health care services of the apartheid era. sport and exercise scientists who strive to enhance health and prevent disease and injury by facilitating participation in physi­ cal activity and sport, should therefore endeavour to address these imbalances. however, their efforts to promote health and fitness amongst all communities should be guided by an understanding of the social, psychological, political and cultural factors which could foster hypokinetic lifestyles or deter participation in health-related physical activity. albert bandura’s social-cognitive theory is therefore used to explain and predict health behaviour in the south african context. it is further advocated that research in the sport and exercise domain shoidd be re-orientated to develop a knowledge base which could guide the design and implementation of effective community-based, health related physical activity programmes in post-apartheid sou til africa. introduction professionals and academics concerned with the pro­ motion of health and fitness through sport, physical exercise and recreation, could be regarded as promo­ tive and preventive health care workers. as such, they should be concerned about indications that non-com­ municable diseases or chronic diseases of lifestyle are on the increase amongst all population groups in south africa. as far back as 1988, life-style related diseases already accounted for 24,5% of all deaths reported in south africa. research conducted in 19 9 2 revealed that 55% o f the population within the 1 5 -6 4 age group were in need of life-style modification and that 16,5% received medical treatment for preventable hyperlipi daemia and hypertension (in that particular year),1 in addition to the physical diseases referred to above, it can also be expected that the mental health of south african citizens has been affected by the political turmoil which has prevailed in south africa over the past few decades. (van rensburg and benatar 1 9 9 3 )' correspondence: i. miller department of human movement studies, university of the western cape, e bag x 17 belville 7535 tel: (021) 959-2350 ascertained that high profiles of stress, trauma, power­ lessness and instability exist in non-white communities. they further cautioned that south africans have inter­ nalised apartheid to the extent that it influences their “psychic make-up and self-image,... minds and emo­ tions,... attitudes and behaviour patterns” .' it can therefore be presumed that south africans’ perceptions of themselves, as well as their views of themselves in relation to society, have been influenced in a positive or negative manner by their socio-political experiences, and that this has ultimately impacted on the psycho­ logical (and general) health and social well-being o f our nation. the health problems cited above can certainly be addressed by human movement specialists (sport and exercise scientists, biokineticians, physical educators, recreation officers) by means of health-related physical activity programmes or rehabilitative movement thera­ py. sufficient evidence exists to verify' that regular phys­ ical activity can bring about: * modifications in blood fat profiles and associated reductions in obesity: * reductions in blood pressure for moderately hyper­ tensive individuals; * reductions in coronary heart disease (chd); * organic changes in the lungs and resultant increases in respiratory efficiency; * reductions in low back pain and postural defects; * preservation of joint and muscle function; * reductions in constipation through improved effi­ ciency o f the digestive system; * promotion of bone health and consequent reductions in fractures and osteoporosis in later life; * reductions in anxiety and depression; * reductions of the adaptations to psychological stress; * improvement of sleeping habits; * and enhancement of self-im age and self confidence.3 8 admittedly, improvement of health cannot be attrib­ uted to regular exercise alone and the positive impact of exercise alluded to above may be limited to specific populations under specific conditions. however, while the rehabilitative and curative value of exercise is acknowledged and advocated, it is regrettable that the preventive potential of regular physical activity is not promoted amongst all sectors of the south african com­ munity. x 9 observed that good health has been deemed more important for whites than for blacks and that a lack of interest in the health status of black patients has been deem ed more important for whites than for blacks and that a lack of interest in the health status of black patients has been discernible to date. although this observation refers to the discriminatory7 provision of curative health care, the lack of sport, gymnasium and recreation facilities in black communities suggests that similar inconsistencies exist with regard to health sports mbdicine march 1996 29 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) t h e h ealth plan p ro p o s e d by the a lriean national c on g ress a d v oca tes a “ re d ress of the negative e ffe c ts ol a p a rth eid h ealth ca re s e r v ic e s ’ . h ow ever, the top ics lu n lcr d iscu ssio n at the 1994 c o n g re ss o l th e s outh a frican f ederation for m ovem ent and l cis iu e s cie n ce s in d ica tes that th is d is cip lin e has not re-orientated it s e lf to the n e e d s o f the “ n ew ” south a frica. instead, it a ffirm s the e m p h a s is w h ich h um an m ov em en t s cien tists place on u n d ersta n d in g the ca p a city and p e r ­ form an ce ol a relatively sm all percen ta g e ol the c o m uuuiitv w h o m aintain active lifestyles anti w h o p a rtici­ pate in e lite , c o m p e titiv e s p o il. t h e valuable co n tr ib u ­ tion o f sport s cie n ce , e xercise s cien ce and b io k in e tics in th is regard, e sp e cia lly in view o f s ou th a frica ’s re entry into the international sport arena, is not c o n te s t­ ed. h ow ever, it can b e q u e stio n e d w h e th e r the d e b il i­ tating socia l, p olitica l, e c o n o m ic and nutritional va ri­ a b les w h ich im pact 011 th e m otor d ev elop m en t and ph ysical p erform a n ce ol the m ajority ol s ou th a fricans, d o c s not warrant m ore attention. m oreover, th is d is c i­ pline sh o u ld be c o n ce rn e d w ith the factors w h ich lo stcr h yp ok in etic lifesty les and d e te r h e a lth -se e k in g b e h a v ­ iour. a social-cognitive analysis ot health behaviour t h e w orld h ealth o rganization (w h o ) d e fin e d health a s an in teg ra ted , m u ltifa ce te d p h e n o m e n o n w h ich e n c o m p a s s e s p h y sica l, p sy ch o lo g ica l ;uid socia l well bein g. s c h lc b u s c h 11 co n cu rre d that age, gen d er, p s y c h o ­ logical status, socio-cu ltu ra l and p olitica l e x p e rie n ce s, ed u ca tio n , religion , the m ed ia , netw ork s w h ich exist in society, a s well as p erson al b e lie fs , valu es and attitu d es c o u ld in flu en ce h e a lth beh avioiu '. h ea lth w o rk e rs sh o u ld th erefore a ck n ow led g e that in d iv id u a ls ’ p e r c e p ­ tions o f h ea lth and h ealth care w ill be in llu cn ccd by the recip roca l in teraction b e tw e e n th eir behavioiu-, internal m ak e-u p and the external environm ent w ith in w h ich they fu n ction .'' t h e socia l-cog n itiv e th eory p ro p o s e d by b andura c o u ld be used to account for the variability and c o n s is ­ tency w h ich exist w ith regard to p rom otiv e health b e h a v io u r in g en era l, and particip a tion in regular p h y s­ ical activity in particular. t he th eory p ostu la te s that ... b eh a v iou r is in flu en ced by th ree self-re g u la to r}’ m e c h a ­ n ism s op era tin g in c o n c e it: p erce iv e d se lf-clfie a cy for o u tco m e attainm ent, o u tcom e e x p ecta tion s, and p e r s o n ­ al g o a l-se ttin g ” . 1:1 it is su g g ested that p e r c e p tio n s about the o u tco m e o f the beh a v iou r (eg. m on etary rew ard, socia l approval, se lf-sa tisfa ction or h ealth b e n e fits ) will in flu ence d e c is io n s abou t p a rticip a tion in p h ysica l activity. sim ilarly, in d iv id u a ls’ b e lie fs of se lf-cffica cy (sk ills, in form ation and a bility) serve as an internal or personal form o f behavioiucon trol w h ich d e term in e involvem ent w ith p h ysical activity.1'* t h e notion that h ea lth behavioiuis in flu en ced by person al p e r c e p tio n s and b e lie fs, is fu rth er d e m o n ­ strated by th e “ lo c u s -o f-c o n lr o l” th eory d e lin e a te d by lau . ‘4 h e co n te n d e d that in d iv id u a ls w h o b eliev e that they have 110 o r little con trol o v er th e negative situation in w h ich th ey find th e m s e lv e s , m ay d e m o n s tr a te “ le a rn e d h e lp le s s n e s s ” . sim ilarly, som e in d ivid uals, the so -ca lle d internals, may p erceiv e th e ir cireiun s ta n ccs and e x p e rie n ce s to b e a c o n s e q u e n ce o f th eir own a ction s and w ill th erefore b e lie v e that they can con trol it, w h e re a s o th e rs, the s o -c a lle d extern als, will regard even ts in th e ir lives to b e u nrelated to th eir a ction s and th erefore b eyon d c o n tr o l.14 t h e fact that a p a rth eid legislation h a s in flu enced the en viron m en t in w h ich t in * ) ungium univeriol oppi'culion tinaa ocwporij 15a & 30g prophylactic tinea cofporis tinea pedis i. 051. b’msaauguh 19951 2. n0t1 jun* ts>95 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) p e o p le lived, th e job s and level o f ed u ca tio n th ey o b ta in ed and h ealth care w h ich they re ceiv ed , m ay in deed have ca u sed disa d va n ta ged in d ivid u als 10 b eliev e that th eir quality o f life cannot be im p roved th rou gh th e ir own efforts. in d iv id u a ls w h o a ssu m e i hat they have little or 110 con trol over th e ir living en viron m en t or that they lack the n ecessa ry sk ills and k n ow led g e (s e lf-c flic a c v ) to im prove th e ir health may (lm s be d is in clin e d to (rv. ll is 1101 su rp risin g that th ese in d ivid u a ls (ex tern a ls) ex p e rie n ce ill-h ea lth as m ore d e b ilita tin g and strcssfid than internals w h o b elieve that they etui con trol th eir h e a lt h .14 h ow ever, p ro p o n e n ls o f em a n cip a tory health e d u c a ­ t i o n ''" ' ca u tion ed dial m ovem en t s p e c ia lis ts n eed lo m ove b ey on d th e in d iv id u a listic p e rce p tio n o f h ealth b eh a v iou r w h ich ciu re n tly c h a r a c te r is e s h ea lth -rela ted p h ysical activity p rog ra m m es. 1( is in d e e d s iin p lis (ic to view health beh a v iou r a s a m atter o f individual re s p o n ­ sib ility and con trol only, without a ck n o w le d g in g the im pact ol (lie socia l and en viron m en tal variables cited above. t h is redu ction ist id e o lo g y sh o u ld be rejected as it cou ld p rolifera te stereoty p in g o f in d ivid u a ls w h o arc unable to m od ify th eir h ealth risk bcluivioiuas w eak, lazy, lacking w ill-pow er, se lf-d is c ip lin e or m otiv a tio n .is a cco rd in g to b andura’s socia l-co g n itiv e theory, social or en viron m en tal factors su ch as s o c io -e c o n o m ic c ir ­ cu m sta n ce s and so cia l rela tio n sh ip s interact in a r e c ip ­ rocal m an n er w ith p sy ch o lo g ica l traits su ch as attitu de and m o tiv a tio n . s im ila rly , a c t io n s an d c o g n it io n s (b e lie fs ) are interactive b eh a viou ra l variables. it can th e re fo re be d e d u c e d that th e so cia l netw ork s w h ich exist w ithin a com m u n ity can a lso in flu ence the h ealth s e e k in g beh a v iou r o f an in d ividual. g c c r t s c n 17 and r itte r1'' rem in d e d us that the so c io -c id tiu a l p e rce p tio n s about h ealth w h ich a rc d e m o n s tra te d by significant o th e rs in the social n etw ork, may p ersu a d e or d issu a d e an in dividual to adopt h e a lth -p ro m o tin g bchaviom \ t he d y n a m ics w ith in the g rou p as w ell as the in d iv id u a ls’ position with the grou p (su p e rio r o r in ferior) will o f cou rse a lso plav a role. r itte r 1" rep orted that " ... a lack of ties may itscll be a sou rec of stre ss, cre a te d bv not having su fficien t socia l tics to p rov id e for intim acy, o r a se n se of b e lon g in g , and the op p ortu n ity to p rov id e as w ell as receive n u rliira u cc'’ . t h e s e p sy ch o lo g ica l factors arc lik ely to im pact negatively 011 tlie h e a lth -se e k in g b eh a v iou r ol m ost s e cto rs o f the b la ck com m u n ity w h o d o not have a c c e s s to ad eq u a te gym n asiu m , recreation and sp orts fa cilities w ithin th eir resid en tia l areas and su b seq u en tly p articipate in le ss su p p ortive socia l n et­ w ork s ou tsid e th eir co m m m iitics. b andura h y p o th e s iz e d that b e h a v io u r co u ld b e a cq u ired by o b se rv in g role m o d e ls . h ow ever, w hite south .vfricans g en erally d om in a te the fitness, r e c r e ­ ation and sport d o m a in s mid b la ck s w h o have been c o n ­ d itio n e d to p c r c e iv c th e m se lv e s as an in ferior race, may find it d ifficu lt to identify w ith o r em u la te w h ite role m o d e ls . n egative se lf-e ffica cy th ou g h ts may in fact d i s ­ cou rage b la ck s from en gagin g in a ctiv ities w h ich have tradition ally b een p ra ctised by w h ite s, re g a rd le s s o f its h ealth p ro m o tiv c poten tial. a lie n 1-' intim ated that low se lf-e ffica cy can be b o o s te d by p erson al p erform a n ce a cco m p lish m e n t or p ositive v ica rio u s e x p e rie n ce s, p a r­ ticularly w hen the in h ib ited b eh a v iou rs arc p erform ed by in d ivid u a ls w h o e x p e rie n ce d sim ila r fears and s e lf­ d oubt. w ankel1" a lso o b s e rv e d that feelin g s o f c o m p e ­ tence, c h o ic e an d p e rce iv e d co n tro l tran slates into enjoym ent and intrinsic m otivation and that th is in tim i co u ld foster e x e rcis e a d h e r e n c e , positive adjustm ent and overall w ell-bein g. t h e critica l con trib u tion o f sport d e v elop m en t p ro g ra m m e s in th is regard is obviou s, but th e need to p ro m o te a b r o a d e r range o f p h ysical a ctiv i­ ties am on gst co m m u n itie s w h o are not involved with m ainstream sport (eg. o ld e r ad u lts) sh o u ld not be d is ­ rega rd ed . s o c io -e c o n o m ic c ir c u m s ta n c e s la rg ely d e te r m in e w h e th e r p e o p le have a c c e s s to h ea lth care fa cilities and s e rv ice s and w h e th e r they will b e m otivated to adopt h e a lth -se e k in g behaviour. m aslow ’s h iera rch y o f n e e d s’4 p ostu la tes that th e b eh a v iou r o f in d iv id u a ls is d e t e r ­ m in ed by th eir n e e d s w h ich in turn a rc d e fin e d by b e lie fs. it can b e a s s u m e d that th e beh a v iou r o f in d i­ vid u a ls w h o have a low s o c io -e c o n o m ic statu s w ill, to a large extent, be in flu en ced by p h y sio lo g ica l and safety n e e d s. m ore affluent in d ivid u als w h o arc able to fulfill b a sic n e e d s su ch as nutrition and safety, will prob a b ly b e driven by e ste e m and self-a ctu a liza tion n eed s. a siu vey c o n d u cte d in 1 989"' revealed that 52,7% o f a fricans, 28,1% o f c o lo u re d s, 10,7% o f in dian s and f,6 % o f w h ites live b e lo w the so -ca lle d b re a d lin e . it can th e re ­ fore be a ssu m ed that a sm a ller percen ta g e o f the b lack com m u n ity will be en cou raged to pa rticip a te in ph vsical activity in o r d e r to look or feel g o o d , w h ile it appears to be a m ajor incentive am ongst w h ite s or m ore affluent in dividuals. d u da and a llis o ir " ex p re sse d co n ce rn about the lack o f cross-cu ltu ra l mial vsis in e xcreisc and s p o il s cie n ce . t h e y c a u tio n e d that d iffe r e n c e s w h ich m av exist betw een w h ite s mid b la c k s with regard to the p e r fo r ­ m ance and p refe re n ce o f p h ysical activity cm inot n e c e s ­ sarily b e attrib u ted to b io lo g ica l and p h ysica l c h a r a c ­ teristics as th ese exp la n a tion s d o not account for intcr an d -in tragrou p d iffe re n ce s. in stea d , they p ro p o s e d that e x e rcise s cie n tists s lio id d analyse the im pact o f s o c io ­ logical p r o c e s s e s s u ch as socia liza tion d iffe r e n c e s and stereotypica l rein forcem ent o f certain s k ills and b e h a v ­ iour, as w ell as p sy ch o lo g ica l p r o c e s s e s su ch as m otiva­ tion, e x p e cta tio n s or p e rce iv e d ability, from a c r o s s -c u l­ tural p ersp e ctive . t h e ir su g g estion that th e e x e rcise fraternity only a ck n o w le d g e s the cu ltu re of w h ite m ain ­ stream p a rticip a n ts is su p p orted by c o lq id io u n 15 w h o o b se rv e d that the m e d ia p r o m o te s w estern values w h ich a ssocia te m e s o m o r p h ic im a g es w ith a c h ie v e ­ m en t, d y n a m ism , d is c ip lin e , con form ity , efficien cy , “ m a id in e s s ” and fem ininity; e cto m o rp h y with w ea k ­ n ess, m alad ju stm en t, u c m o tic is m , an ti-social te n d e n ­ c ie s , im a ttra ctiven css and co ld n e s s ; and e n d o m o rp h y w ith laziness, in efficien cy, s e lf-in d u lg e n ce , u n h e a lth i­ n ess and im attractiven css. it s h o u ld b e a ck n ow led g ed that th e se p e rce p tio n s are not n ecessa rily su p p orted bv all cultural g rou p s, and th at som e co n u n iu iitics may be less in spired to ch a n g e th eir life-styles in o r d e r to attain th e p re su m e d id ea l im ages o f h ealth and attrac­ tiveness. w om en are apparently very su sce p tib le to p ressu re from s o c ie ty and th e m e d ia to en n d a te im a g e s o f the ideal w om an w h o is d e p ic te d a s th in , active and fit. t h ey are th e re fo re c o e r c e d to re d u ce w eigh t, often lea d in g to bu lim ia and anorexia nervosa. t h e im pact o f g e n d e r stereotypin g is a lso d e m o n stra te d in o th er a sp e cts o f health behaviour. t h e fact that m ost s o c i­ e tie s frow n upon w om en w h o abu se a lco h o l or sm ok e, and g en erally a sso cia te th ese b eh a v iou rs w ith “ m a n li­ n e s s ” , m ay accou n t for the h ig h e r in cid e n ce o f th ese risk-taking b eh a v iou rs am on gst m en. h ow ever, m en arc m ore likely to engage in ph ysical and recreational activ­ sports medicine march 1996 31 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ity due to the fact that they generally have less child­ care or domestic responsibilities.21 women nevertheless demonstrate more concern about health as they are generally responsible for the health care of the family. they are also more dependent on medical care due to their complex and demanding reproductive functions. duncan, duncan and mcauley22 identified that social integration or network support appears to enhance exercise compliance amongst men, while attachment and emotional support as well as reassurance of worth motivate women to persist with exercise. it could be expected that individuals’ level of educa­ tion will impact on their health behaviour. however, bailey and macphee23 observed that people who have the necessary knowledge about the repercussions of health-risk behaviour will not necessarily be dissuaded from engaging in it. according to the so-called health belief model, people will only be prepared to modify their lifestyles if they perceive themselves to be at risk. the self-regulation model contends that individuals’ responses are determined by their understanding and personal experience ol health problems. these reasons were nevertheless found to be poor motivators to exer­ cise, and it is believed that knowledge of the positive outcomes of regular physical activity, rather than infor­ mation about future health risks, may be greater incen­ tives to exercise. t h is observation concurs with bandura’s social cognitive theory which hypothesizes that “ ... the perception that physical activity will lead to a valued outcome will motivate individuals to partici­ pate” .13 in conclusion, exercise scientists are urged to adopt a multi-factorial and trans-cultural orientation to pro­ motive health care. schlebusch’s 11 admonition that health-risk behaviour and unhealthy lifestyles are almost intractable in developing communities and that concentrated efforts are required to facilitate change, should serve as a challenge for exercise scientists who wish to contribute to the reconstruction and develop­ ment o f their communities. a t issue is the accommodation of health profession­ al roles and the structure of the health care system to a h a nging knowledge base that incorporates culture and social process as important influences upon health behaviour.24 t he social-cognitive theory outlined in this paper is not the only framework which can be used to analyze human thoughts and actions, but it can nevertheless serve as a useful guide to predict variations and consis­ tencies regarding participation in health-promotive physical activity in post-apartheid south africa. however, additional research on the impact of the aforementioned variables is essential to ensure that physical activity programmes which are aimed at com ­ munity-based health promotion are relevant and sus­ tainable. references 1. steyn, k , fourie, j. & bradshaw, d. (1992). the impact o f chronic diseases o f lifestyle and their major risk factors on mor­ tality in south africa. south african medical journal, vol 82, october: 227-231. 2. van rensburg, h.c.j. & x, s.r. (1993). the legacy o f apartheid in health and health care. south african journal o f sociology, vol 24 ( 4 ) : 99-111. 3. sallis, j.f. & mckenzie, t.l. (1991). physical education’s role in public health. research quarterly for exercise and sport, vol 62 ( 2 ) : 124-137. 4. corbin, d.e., metal-corbin, j. & biddle, s. (1 9 8 9 ). educating children about a geing and lifetime health related fitness. 5. mullen, k.d., gold r.s., belcastro, p.a. & mcdermot, r.j. (1990). connections for health (2nd e d .). dubuque, ia : wm.c. brown. british journal o f physical education, winter: 191-194. 6. bruhn, j.g. (1988). lifestyle and health behaviour. in gochman, d.s. (e d), health behaviour emerging research perspectives. london: plenum press. 7. miller, d.k. & allen, t.e. (1979). fitness: a lifetime commitment. minnesota: burgess publishers. 8. dinliman, g.b. & greenberg, j.s. (1983). health through discovery (2nd e d .). london: addison-wesley. 9. x, s.r. (1991). medicine and health care in south africa five years later. new england journal o f medicine, 3 2 5 (1 ): 30-36. 10. african national congress (1994). a national health plan for south africa. lesotho: bahr mapping and printing. 11. shlebusch, l. (1993). the management o f health risk behaviour. continuing medical education, vol 11 ( 9 ) : 1645 1652. 12. allen, b.p. (1994). personality theories. london: allyn and bacon. 13. dzewaltowski, d .a.; noble, j.m. & shaw, j.m. (1990). physical a ctivity participation: social cognitive theory versus the theories o f reasoned a ction and planned behaviour. journal o f sport and exercise psychology, 12: 388 405. 14. lau, r.r. (1988). beliefs about control and health behaviour. in gochman, d.s. (e d .), health behaviour emerging research perspectives, gochman. london: plenum press. 15. colquhoun, d. (1 9 8 9 ). health related fitness and individualism: continuing the debate. british journal o f physical education, autumn: 118-122. 16. fawcett, t. (1991). physical education and health where are we: now? the bulletin o f physical education, vol 27 ( 3 ) : 17 20 . 17. geertsen, r. (1988). social group characteristics and health behaviour. in gochman, d.s. (e d), health behaviour emerging research perspectives. london: plenum press. 18. ritter, c. (1 9 8 8 ). social supports, social networks, and health behaviour. in gochman, d.s. (e d .), health behaviour emerging research perspectives. london: plenum press. 19. wankel, l.m. (1993). the importance o f enjoyment to adherence and psychological benefits from physical activity. international journal o f sport psychology, 24: 151-169. 20. duda, j.l. & allison, m.t. (1990). cross-cultural analysis in exercise and sport psychology: a void in the field. journal o f sport and exercise psychology, 12: 144-131. 21. waldron, i. (1988). gender and health related behaviour. in gochman, d.s. (e d .), health behaviour emerging research perspectives. london: plenum press. 22. duncan, t.e.; duncan, s.c. & mcauley, e. (1993). the role o f gender-specific provisions o f social relations in adherence to a prescribed exercise regimen. journal o f sport and exercise psychology, 15: 220-231. 23. bailey, c.i.a. & macphee, s.j. (1 9 8 9 ). community health related fitness testing and promoting activity: the north staffordshire experience. british journal o f physical education, summer: 68-70. 24. weidman, h.h. (1988). a transcultural perspective on health behaviour. in gochman, d.s. (e d.), health behaviour emerging research perspectives. plenum press. | | 32 sports medicine march 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) guest editorial a n apparent a nom aly is that a m edical curriculum can b e considered com p lete even if it pays only passing reference to the largest organ in the human body, skele­ tal m uscle which can com prise up to 25 kg in the aver­ a g e male. skeletal m uscle, it would seem , lacks the rom antic charism a o f that far m o re puny (less than 5 0 0 g) organ, the heart. yet the established, indeed re­ vered specialities o f cardiology and cardiac surgery and a thriving industry in cardiovascular m edicin es attest to the far greater im portance hum ans and the m edical profession attach to their hearts. physiotherapists, neu­ rologists and specialists in physical m ed icin e are perhaps the sole m edical practitioners for w h om dis­ orders o f skeletal m uscles are o f m o re than passing in­ terest. but if much o f m ed icin e has yet to em brace the sig­ nificance o f such a w eigh ty organ, powerful forces at its fringes will ultim ately influence that indifference. in­ d eed the sin gle m ost im portant factor in fluencing the cinderella status o f skeletal m uscle in the m edical cur­ riculum has been the growth o f the exercise sciences. it is perhaps obvious that those w ho would study the human in m otion should begin to cham pion the study o f the organ o f m ovem ent. but even am ongst the exercise scientists there are still those w ho are reluctant to believe the im portance o f the skeletal muscles in exercise and sport. s o a popu­ lar view is that exercise perform ance esp ecially during high intensity exercise o f short duration is lim ited by the capacity o f the heart to provide an adequate o xy­ gen supply to the large m uscle mass that is activated during this type o f exercise. if this is true, the main e f­ fect o f physical training we are led to believe must be to develop so-called “cardiovascular fitness” . yet there are solid argum ents that question the scientific validi­ ty o f the pioneerin g studies on which this concept is based.1 furtherm ore the factor that best identifies success­ ful endurance athletes is the ability specifically o f their skeletal muscle to resist the developm ent o f fatigue dur­ ing p rolon g ed exercise.2 in these athletes it is their muscles, not their hearts, that determ in e their success. then perhaps m ost challenging is the new paradigm which su ggests that the exercise tolerance o f persons with advanced heart disease is lim ited by an associat­ ed m yopathy (o f chronic disease), rather than by the severely im paired function o f their diseased hearts.3 a s a result, exercise training which im proves skeletal m uscle function, can enhance exercise capacity and re­ duce exercise-related sym ptom s even in persons with advanced heart disease, even heart failure.4 with such advances it is perhaps appropriate that the review section o f the first issue o f our re-launched jour­ nal should focus attention on skeletal m uscle and e x ­ ercise. t h e aim has been to review various aspects o f skeletal m uscle function that will be o f interest to the different disciplines that com prise the m em bership o f the south african sports m ed icine association. in the article devoted to the basic sciences, dr kathryn myburgh phd, w ho has recently com pleted her post-doctoral studies in the m uscle research laborato­ ry o f dr r oger cooke in san francisco, carefully reviews the historical developm ent, still less than 50 years old, o f the b iochem ical and structural studies that have laid the foundation o f the m odern understanding o f how m uscles contract. s he next discusses the different con­ tractile properties including force production and resis­ tance to fatigue o f the separate m uscle fibres and ex­ plains how the different (iso)form s o f the contractile pro­ teins can explain s o m e o f these functional differen ces she concludes that training and other interventions alter not on ly m uscle fibre size, their m itochondrial en­ zym e content and their substrate utilization patterns but also the m ix o f the different contractile protein isoforms com prising the different fibres. s h e wonders whether sporting success m ight b e linked to specific m olecular com binations in the different skeletal m uscle fibres. in­ d eed on e must ask whether one sp ecific com bination o f skeletal m uscle contractile protein isoforms explains the success o f the sprinters o f west african origin and another, different com bination the exceptional fatigue resistance o f the east african distance runners? c lear­ ly if we are to honour our continent and its peoples, those questions must b e tackled and answered by a fri­ can scientists. perhaps dr myburgh’s article will have served its purpose if it were to encourage o n e young scientist to ch ose a career that will address these ques­ tions. t h e dynam ic disorders o f skeletal muscle provide an intriguing insight into the interface between the basic and the clinical sciences. th ese extrem ely rare condi­ tions which produce sym ptom s only during exercise are o f interest to clinicians who must consider them in the differential diagnosis o f conditions causing exercise related sym ptom s. for the basic scientist, patients with these conditions provide a unique m odel for the study o f the biochem ical changes causing (prem ature) fatigue during exercise. t h e surprising finding is that fatigue in patients with m ca rdle’s syndrom e occurs, as expect­ ed, without changes in blood lactate levels or blood ph but, m ore interestingly, without a large reduction in m uscle a t p concentrations sa journal of sports medicine september 1994 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) g u e s t editorial o n e explanation for this finding is that skeletal mus­ cle function during exercise is regulated to prevent a reduction in m uscle a t p content sufficiently large to produce m uscle rigor. this postulate holds that under any condition in which the rate o f m uscle a t p produc­ tion is approaching so m e m axim u m value, the rate o f muscle a t p use is reduced by regulatory processes that reduce the force and frequency o f m uscle fibre contrac­ tion (thereby reducing the rate o f atp use). thus in this model, fatigue o f skeletal muscle during exercise is con­ ceived as a regulatory process which links skeletal mus­ cle contractile function to the rate o f a tp production (perhaps through changes in the levels o f m etabolites o f a tp breakdown including pi and a d p ) specifically to prevent the d evelop m en t o f m uscle rigor. a n other interesting finding is that patients with mc a rd le’s syndrom e exhibit an excessive rise in cardiac output, m uscle b lo od flow and ventilation during exer­ cise. this is because o f a large fall in peripheral vascu­ lar resistance caused by excessive vasodilation in the active skeletal muscles. m etabolic interventions that reduce m uscle a d p and pi concentrations during exer­ cise reduce the vasodilation, the skeletal m uscle blood flow and ventilation. interestingly the m etabolic disord­ er c o m m on to all form s o f m uscle disease is that mus­ cle a d p and pi levels rise m ore rapidly than normal during exercise; conversely highly trained muscle is able to resist this change until very high intensities o f exer­ cise are reached. hence these studies provide intriguing evidence for m etabolic factors in skeletal m uscle that influence the cardiovascular and respiratory response to exercise and the onset o f subjective sym ptom s o f fatigue. in the section dealin g with clinical aspects o f skele­ tal muscle, dr m ike lam bert and professor steven den­ nis review perhaps the m ost co m m on skeletal muscle ailm ent in the exercising population, what is popular called m uscle stiffness but w hich now enjoys the m ore elaborate official title o f d elayed o nset m uscle s ore­ ness (dom s). in this review we learn that d o m s is not due to lac­ tate accum ulation and retention in the previously ac­ tive muscles. this is perhaps on e o f the com m on est m isconception in the general sporting population. rather d o m s is due to tissue d am age from which there is a delayed recovery; dam age is especially likely after eccentric exercise, a finding well-known to runners in the “down” com rades marathon. each step on the long downhill section from k lo o f to the finish in durban places a large eccentric load on the runner’s quadriceps muscles. a n d the results are very apparent the follow ­ ing day. readers o f this article will now b e able to give a detailed scientific explanation to help their runners through their post-race misery. practical inform ation provided by these authros is that neither anti-inflam m atory m edications nor rest m ake any real difference to the rate o f recovery from doms. but training reduces the amount o f muscle stiff­ ness sym ptom s during a subsequent bout o f similar e x­ ercise. th is effect m ay last for w eeks to months. t h e wish o f the authors is that we have been able to convey som e o f the excitem ent and enthusiasm we feel in our studies o f skeletal m uscle in active persons and the relevance that such studies have for the exer­ cise sciences and for clinical sports m edicine. lastly we would h op e that, perhaps, we have been able to convince you that, in exercise and sport, the heart o f the m atter is skeletal msucle. references 1. noakes td. implications o f exercise for prediction o f athletic per­ formance: a contemporary perspective. m ed sci sports exerc 20: 319-330, 1988. 2. coetzer p, noakes td, sanders b, lambert ml, bosch afi, wig­ gins t and dennis sc. superior fatigue resistance of elite black south african distance runners. j appl physiol 75: 1822-1827, 1993. 3. minotti jr, christoph i, oka r, weiner mw, wells l and massie bm. impaired skeletal muscle function in patients with congestive heart failure. relationship to systemic exercise performance. j clin inuest 88: 2077-2082, 1991. 4. sulliuan mj, higginbotham m b and cobb fr. exercise training in patients with severe left uentricular dysfunction. circulation 78: 506-515, 1988. professor tim noakes guest editor 2 sa journal of sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the south african journal of sports medicine guest editor prof t d noakes university of cape town editorial board dr m p schwellrtus university of cape town dr m e moolla private practitioner durban dr a venter private practitioner bloemfontein dr p de jager private practitioner pretoria dr j skouuno private practitioner johannesburg dr i surve private practitioner cape town dr p schwartz private practitioner port elizabeth prof g strydom potchefstroom university prof r stretch university of fort hare mrs j morton private physiotherapist durban mr d rehbock podiatrist johannesburg international advisory board lyle j micheli associate clinical professor of orthopaedic surgery boston, usa chester r kyle research director, sports equipment research associates california, usa prof hc wildor hollmann president des deutschen sportsrztebundes koln, west germany howard j green professor, department of kinesiology ontario, canada george a brooks professor, department of physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke associate professor, biology d e p a rtm e n t, university of colorado colorado, usa graham n smith physiologist glasgow, scotland volum e 1 num ber 1 september 1994 contents editorial td noakes 1 forthcoming conferences 5 the dynamic disorders of skeletal muscle metabolism with special reference to exercise td noakes 6 muscle proteins and the contractile properties of muscle fibres kh myburgh 11 delayed — onset — muscle — soreness ml lambert and sc dennis 18 advances in sports equipment technology that enhance performance cr kyle 21 die effek van ’n stresweerbaarheidsprogram op valskermspringers d scheepers en j potgieter 30 the editor the sooth african journal of sports medicine p o box 38567, pinelands 7430 prod uction advertising andrew t hom as marika de waal/andrew thom as pub lish ing r eprod uction qlenbarr publishers cc output reproduction dunkeld 2196 printing tel: (011) 442-9759 hortors fax: ( o i l ) 880-7898 cover sponsored by ciba-geigy t h e view s expressed in individual articles are the personal view s o f the authors and are not necessarily shared by the editors, the advertisers or the publishers. n o articles m ay b e reproduced without the written consent o f the publishers. sa journal o f sports medicine september 1994 3 r ep ro du ce 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drawings should b e on white board, arranged to conserve vertical space. w here possible, lettering on figures should b e d on e by m eans o f a stencil, bearing in m ind that reduction to 75 m m for a sin­ g le colum n or 155 m m for d ou ble colum n should not render letering illegible. explanations should be included int he len gen d and are redundant on the figure itself. 4. figure numbers should b e clearly m arked on the back o f prints, and the top o f the illustration should b e indicated. 5. w here identification o f a patient is possible from a photograph the author must subm it a consent to publication signed by the patient, or by the parent or guardian in the case o f a minor. 6. if any tables or illustrations submitted have been pub­ lished elsewhere written consent to republication should be obtained by the author from the copyright holder and the au th ors). 7. a lim ited num ber o f illustrations is allow ed free at the discretion o f the editor. r eferences 1. references should be inserted in the text as superior numbers, and should be listed at the end o f the arti­ cle in numerical order. d o not list them alphabeti­ cally. 2. it is the author’s responsibility to verify references from the original sources. 3. references should be set out in the vancouver style, and only approved abbreviations o f journal titles should b e used; consult the list o f journals indexed in index m edicus for these details. n am es and ini­ tials o f all authors should be given unless there are m ore than six, in which case the first six nam es should b e given follow ed by “et al” . first and last p a g e numbers should b e given. journal references should appear thus: a. peter s. acute ham string injuries a m j sports m ed 1994; 12(7): 395-400. b ook references should be s et out as follow s: a. w illiam s g. textbook o f sports m edicine. 2nd edi­ tion: butterworth, 1989: 101-104. b. vanderm ere p, russel p. biom echanics o f the hip joint. in: n ord ien pe. jeffcoat a, e d s clinical bi­ o m ech a n ic s philadelphia: w b saun ders 1990: 472-479. 4. “ unpublished observations” and “ personal com m u ­ nications” m ay b e cited in the text, but not in the reference list. manuscripts accepted but not yet pub­ lished can b e included as references follow ed by “(in press)” . galley proofs will b e forwarded to the author in g o o d tim e before publication. proofs not returned within 48 hours will b e regarded as approved. bear in m ind that alterations to typeset articles are costly and m ay be charged to the authors change o f address t h e editorial departm ent should b e n otified o f any address changes so that proofs and invoices m ay be m ailed without delay. a ll manuscripts and correspondence should b e ad­ dressed to: t h e editor, south a frican journal o f sports m edicine, p o b ox 38567, p in eland s 7430. 4 sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) forthcoming conferences national a ugust 22-26, 1994. s o u t h e r n a f r ic a n n u tr i­ t io n congress, royal hotel, d urban . focus will b e on diseases o f over and undernutrition and life­ style, the role o f nutrition in phc, nutritions and food policy, the sensory aspects o f fo o d and how it relates to the practice o f nutrition and dietetics and the food industry, nutrition education and sports nutrition. for further details please contact: m s carol herbert; con­ gress co-ordinating com m ittee, p o box 1209, durban, 4000. fax: (031) 304-9652. august, 1994. 40th s a o a a n n u a l congress, pretoria. guest speakers: dr allan e gross, toronto, canada; dr r w bucholz, university o f texas, usa. con­ tact: dr l van wyk, 404 m u elm ed m edical centre, 577 pretorius street, arcadia, pretoria, 0083. tel: (012) 341-7573. o ctob er 3-4, 1994. w o r k s h o p o n com puter b a s e d e x e rc ise fo r t e a c h in g physiology, a n d : o cto b er 5-7, 1994. 2 2 n d a n n u a l c o n g r e ss o n t h e ph y sio lo g ic a l s o c ie t y o f s o u t h e r n a f r ic a , ste lle n b o s c h . for further details please contact: dr a w van rijswijk, d epartm ent o f human and a n im al physiology, university o f stellenbosch, 7600. o ctob er 5-7, 1994. sc ie n tific c o n g r e s s o f so uth a f r ic a n a s s o c ia t io n for lab o r a to r y a n im a l s c ie n c e (s a a l a s ), jo h an n e sb u r g . t h e transnet conference centre, esselen park near jan sm uts airport. contact: miss m oniqu e d e villiers, n a ­ tional institute for virology, private b ag x4, s andring­ ham, 2131. tel: (011) 882-9910. fax (011) 882-0596. n o vem b er 27-30, 1994. t h e s o u t h e r n a f r ic a c a r d ia c s o c ie t y 19th b ie n n ia l congress. education building, university o f c ape town. contact: mrs s ally elliott, postgraduate m edical centre, u c t m ed school, observatory, 7925. tel: (021) 406-6381. fax: (021) 448-6263. march 22-24, 1995. sixth so uth a f r ic a n spo rts m ed icine a s s o c ia t io n congress, elangen1 h o t e l durban. contact mrs miriam tennant, sports medicine, u c t m edical school, observatory, 7925. tel: (021) 406-6504. fax: (021) 47-7669. international august 10-14, 1994. c o m m o n w e alth g a m e s 1994, in t e r n a t io n a l sc ie n tific congress, u n iv e r ­ sity o f victoria, bc, c a n a d a . contact: c om m on ­ wealth g am es international s cien ce congress, confer­ ence services, division o f university extension, univer­ sity o f victoria, p o box 3030, victoria bc, canada v8w 3n6. fax: 604 721 8774. august 17-19, 1994. 7th in t e r n a t io n a l c o n ­ g ress o n o b e sity — s a t e llit e sym posium , quebec, c a n a d a . contact exercise and o besity sat­ ellite, c/-angelo tremblay, physical activity sciences la­ boratory, peps, university laval, ste-foy, quebec, cana­ da g1k 7p4. tel: 418 656 7294. fax: 418 656 3020. august 29-03 sept, 1994. t h e c e n t e n n ia l olym ­ pic congress, paris, f r a n c e contact internation­ al o lym p ic c om m ittee, chateau d e vidy, ch-1007 lausanne, switzerland. tel: 41 21 621 6111. fax 41 21 621 6216. s ep tem b er 10-16, 1994. 25th f1ms w o r ld c o n ­ gress o f s p o r t s m edicine, athens, greece. abstracts should be submitted before january 31, 1994. for further details contact: o rganization idea, 24 vou lis street, 10563, athens, greece. tel: 32 42 045, 32 42 529. fax: 32 21 023. s ep tem b er 16-18, 1994. o r th o p ae d ic medicine. a n in tr o d u c to r y c o u rse o n d ia g n o s is a n d in je c tio n tec h niques, s a n luis obispo , ca, usa. for further details contact: t h o m a d orm an md, attention: shirley hulin, 171 north santa rosa street, s te a, san luis obispo, ca93405-1322, usa. o ctob er 3-8, 1994. a u s t r a l ia n spo r ts m ed icine fe d eratio n — in t e r n a t io n a l c o n f e r e n c e in s c ie n c e a n d m e d ic in e in sport, brisbane, au str alia. contact australian sports m edicine fede­ ration limited, p o b ox 897, belconnen a c t 2616, aus­ tralia. tel: 06 251 6944. fax: 06 253 1489. a pril 5-7, 1995. c o n f e r e n c e o n n u tr itio n a n d ph ysic al activity, t o o ptim ize pe r f o r m a n c e a n d w ell-being. t h e ritz-carlton, buckhead, atlan­ ta, georgia, usa. contact: m s lili c merritt, internation­ al life s cien ce institute, 1126 sixteenth street, nw, washington, dc 20036, usa. tel: 202 659 0074. fax: 202 659 3859. may 23-27, 1995. 10th in te r n a tio n a l sym posium o n a d a p t e d physical activity. contact 10th isa pa secretariat, t h e n orw egian university o f sport and physical education, d epartm ent o f information, post boks 40, kringsja, n-0807, oslo, norway. s ep tem b er 14-17, 1995. t h e xith f in a w orld spo r ts m ed ic in e congress. athens hilton hotel, greece. contact: public relations center, halen haly vides, foz m ichalaropoulou street, 115-28 athens, greece. tel: (301) 775 6336 — 777 1056. fax: (301) 771 1289. □ sa journal of sports medicine september 1994 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the dynamic disorders of skeletal muscle metabolism with special reference to exercise td noakes mb chb md facsm introduction most o f the skeletal m uscle disorders encountered in clinical m edicine are o f a sufficiently severe nature that they cause such weakness that participation in physical activity is not possible. these degenerative or myopathic disorders cause progressive m uscle weakness and atrophy usually leadin g to death at a relatively young age. however there are a group o f skeletal m uscle disord­ ers which cause sym ptom s only during exercise. these are known as the dynam ic m uscle disorders and are com patible with an unaltered life expectancy. t h ey are o f special interest to sports scientists as the b io ch em i­ cal abnorm alities present in these conditions allow in­ sights into m etab olic factors in skeletal m uscle which influence cardiovascular function during exercise, and to sports physicians because these conditions need to be considered in the differential diagnosis o f exercise induced syndromes. in addition, the clinical syndrom es o f malignant hyperpyrexia, exercise-induced heatstroke and rhabdom yolysis which acute renal failure are prob­ ably inter-related and m ay be caused by o n e or m ore o f the d ynam ic disorders o f skeletal m u scle m eta b o­ lism, perhaps as yet undefined. this review will em phasize esp ecially the dynam ic skeletal m uscle disorders that cause sym ptom s during exercise. n o attention is paid to the degenerative skele­ tal muscle disorders that cause sym ptom s at rest these conditions are well described in conventional m edical texts and are o f no special interest to sports practition­ ers. it should be em phasized that the dynam ic disord­ ers o f skeletal m uscle m etabolism are exceedingly un­ com m on. t h e intellectual interest they evoke is quite out o f proportion to their clinical importance. clinical presentation t h e dynam ic disorders o f skeletal m uscle m etabolism are characterized by the follow ing features: first, there are no sym ptom s at rest. in par­ ticular, muscle weakness, a characteristic feature o f the atrophic and destructive m yopathies, is absent. second, the diagnostic feature is the early on ­ set o f fiatigue — easy fiatigueability — during exliberty life chair o f exercise and sports science and m r c / u c t bioenergetics o f exercise research unit department of physiology university o f cape town medical school observatory south africa ercise, even when the exercise is o f a m ild in­ tensity. third, the cardiorespiratory response to exer­ cise is abnorm al with an elevated heart rate, cardiac output and m inute ventilation. fourth, there m ay b e rhabdom yolysis with m yoglobinuria. if severe, this m ay lead to acute renal failure. classification th ere are four subgroups in this category: — defects o f carbohydrate metabolism, the classic form o f which is m ca rd le’s syndrom e. — d efects o f lipid m etabolism . — d efects o f m itochondrial function. — d efects o f adenine n ucleotide m etabolism . mcardle’s syndrome in this condition which has its onset early in life, either late childhood or early adulthood, the patient has se­ vere exercise intolerance (m ca rdle, 1951). th ere is the onset o f m uscle pain and contractures during m ore vigorou s exercise. t h e contractures are electrically si­ lent unlike nocturnal cramps in which there is increased electrical activity. if the exercise is continued, the con ­ tractures m ay lead to ischaem ic d a m a g e o f the m us­ cle leading to m yoglobinuria with possible renal dam age. in less severe cases, there m ay also be m us­ cle swelling and soreness, follow ed after exercise by elevated serum en zym e activities and m yoglobinuria, on occasion. but if the exercise is continued at low intensity, the patient experiences a “ second w ind” in which the pain dim inishes so that he o r she is able to continue exer­ cising albeit at a relative low exercise intensity. factors that exp ed ite the onset o f the second w ind include e x ­ ercising in warm w eather and the avoidance o f a high carbohydrate m eal shortly before exercise. factors that aggravate the sym ptom s are obviously the reverse — exercising in the cold and eating a high carbohydrate m eal shortly before exercise. carbohydrate ingestion causes serum-free fatty acid concentrations to fall there­ by lim iting the availability o f this alternate fuel for the exercising muscles. factors which reduce skeletal mus­ cle b lo od flo w also delay or prevent the onset o f the second wind. t h e biochem ical hallm ark o f the condition is the failure o f the exercising m uscles to produce appropri­ ate am ounts o f lactate during vigorou s or ischaem ic exercise. m ca rd le (1951) recogn ized the sim ilarity b e ­ tween this clinical picture and the develop m en t o f con6 sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) muscle metabolism tractures without lactate production by m uscles p o i­ soned with the glycolytic inhibitor iodoacetate. he con­ cluded that patients with this syndrom e must be suffer­ ing from an enzym atic defect in the gly co g en oly tic or glycolytic pathways. indeed, the absence o f on e or m ore o f the follow ing en zym es have been described in pa­ tients w ith the sym ptom com p lex described by mcar dle: g ly co g en phosphorylase, g ly c o g e n phosphorylase b kinase, phosphofructokinase, phosphoglycerate kinase, ph osphoglycerate mutase and lactate dehydro­ genase. a ll these enzym e defects reduce the ability o f the cell to produce atp by oxygen-independent pathways. this is confirm ed by the low levels o f gly colytic interm edi­ ates and pyruvate m easured by m uscle biopsy during exercise in these patients (k on o et al 1984; wahren et al 1973). in addition, there is an inability to produce pyruvate at a sufficiently fast rate to fuel oxidative m etabolism (lew is and haller, 1986). patients with gly co gen phosphorylase deficien cy are able to oxidize glucose and free fatty acids for en erg y whereas those with en zym e deficiencies below phosphorylase can o x ­ idize only free fatty acids as interruption o f the g ly c o ­ lytic pathway prevents the c om plete m etabolism o f glu­ cose — > pyruvate — > acetyl c o a for further oxida­ tion in the krebs cycle. thus whereas the provision o f glucose by infusion will increase the exercise tolerance o f patients with a pure phosphorylase deficiency, such infusions will have no effect on those with en zym e defects in the gly colytic pathway. t h e result o f this inability to supply adequate sub­ strate to the krebs cy cle for oxidative m etabolism is that, during exercise, there is an abnorm ally large decrease in m uscle pc r concentrations and m uscle ph and a large increase in m uscle pi concentrations. w hen stimulated electrically, the muscles o f patients with this syndrom e also lose their action potentials, pos­ sibly su ggestin g that glycolytically-produced a t p m ay be required for m aintaining the excitability o f m e m ­ branes esp ecially the sarcolem m a and ttubules. disturbances o f oxygen transport and cardiac function in patients with m ca rdle’s syndrom e oxygen transport and utilization m cardle’s syndrom e had been used as a m odel to study the m etab olic factors in the active skeletal m uscle that influence cardiovascular function (lew is and haller, 1986; lewis et al 1991). it is found that the m axim um oxy gen consum ption (v 0 2 max) o f patients with m ca rdle’s syndrom e is about 18 ml 0 2 k g -1 v iin -1 o r roughly half that found in nor­ mal patients. t h e reduced v 0 2max is not due to re­ duced m uscle mass and is thus distinct from the low vo2 max observed in patients with prim ary m uscle dis­ eases such as muscular dystrophy in which there is m uscle wasting. t h e low v 0 2max o f patients with m ca rd le’s syn­ drom e has been related to the abnorm ally slow rate o f substrate flux through the krebs cycle and the electron transport chain. t h e inability to fuel the krebs cycle with pyruvate causes the krebs cycle to b e c o m e “ run down” . thus the rate o f form ation o f m itochondrial reducing equivalents (n ad h and fadh2) will ultimately lim it the rates o f oxidative phosphorylation and there­ fore the v 0 2max. although w hole body v 0 2 is norm al at rest in these patients, at any given w orkload total b o d y v 0 2 is greater than normal. this is explained by an increased oxygen consum ption o f the cardiac and respiratory m uscles due to an excessive tachycardia and elevation o f systolic b lo od pressure and a greater than normal pulm onary ventilation. respiratory exchange ratios dur­ ing exercise are also abnorm ally low indicating an in­ creased reliance on fat as the m ajor m etabolic fuel for exercise. t h e v 0 2 max o f patients with m ca rd le’s syndrom e is increased by intravenous glucose or lactate infusions. even then, blood lactate concentrations d o not increase indicating that a m ajor reason for the reduced w ork ca­ pacity o f these patients is a lack o f oxidizable substrate, esp ecially pyruvate, to fuel the krebs cycle. this also indicates that b lood glu cose cannot fully substitute for m uscle g ly cogen as an oxidative substrate in short-term heavy exercise. sim ilarly an elevation o f serum -free fatty acid con ­ centrations also increases v 0 2 max by the order o f 18-25%. thus a lim itation in the availability o f free fat­ ty acids also contributes to the low v 0 2max o f these patients. cardiovascular function patients with m cardle’s syndrom e show an hyperkinetic circulatory response to exercise. t h is hyperkinetic cir­ culatory response is not due to cardiac or vascular dis­ ease; cardiac m uscle is spared in m ca rdle’s disease b e ­ cause o f the presence o f cardiac specific glycogen phos­ phorylase isoenzymes. there is also no evidence for ab­ norm al g ly c o g e n ph osphorylase activity in vascular sm ooth muscle. t h e elevated cardiac output during subm axim al e x ­ ercise is b elieved to result from excessive vasodilata­ tion in the active m uscles possibly related to the large fell in intramuscular pc r and the excessive rise in pi concentrations this hyperkinetic circulation is partial­ ly norm alized during the infusion o f free fatty acids or during exercise when serum -free fatty acid concentra­ tions are elevated this finding links m echanism s regu­ lating system ic h aem odynam ics and local vasodilata­ tion with the availability o f oxidizable substate to the contracting muscles. hence it is not only the availabili­ ty o f o xygen that controls peripheral vascular function. glucose infusion sim ultaneously decreases both the cardiac output and the extent o f the d ecline in pcr and the rise in pi concentrations during exercise in these patients. this indicates that there is probably a recipro­ cal relationship between skeletal m uscle blood flow and cellular atp/adp.pi ratios (the phosphorylation poten­ tial). this su ggests that the crucial m etab olic conse­ quence o f m ca rdle’s disease is an abnorm ally large d e ­ cline in this ratio in m uscle during exercise. t h e exact vasodilator substances acting in m ca rdle’s syndrom e are not known but increased concentrations o f lactate and hydrogen ions, o r a low arterial p 0 2 o r increased p c 0 2 have all been excluded as n on e is d if­ sa journal of sports medicine september 1994 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) muscle metabolism ferent from values m easued in norm al persons. thus the likely vasodilators are phosphate, potassium and adenosine, the latter derived from amp. o f these, intra­ muscular phosphate concentrations are known to in­ crease steep ly in these patients during exercise and there is also increased potassium release by muscle. either or both could b e im portant vasodilators in this disease. alternatively, these m etabolites m ay stimulate skeletal m uscle (g roup 111 and iv) afferents which then induce the excessive cardiovascular response during ac­ tivity (lew is et al 1991). in contrast, during static exercise, patients with m c­ a rd le’s syndrom e do not show the expected increase in m uscle sym pathetic nerve activity. thus, in normal m uscle this reflex is probably activated by increased rates o f glyco gen olysis with a fall in m uscle ph (pryor et al 1990). patients with m ca rd le’s syndrom e also show an ab­ normal increase in am m onia production by muscle, fur­ ther indicating/increased a m p production with conse­ quent deam ination to am m on ia and imp. glucose in­ fusion also reduces the production o f am m onia; thus a reduction o f am m on ia production m ay also b e a fac­ tor reducing the abnorm al cardiac output in these pa­ tients. biochemical features o f fatigue in mcardle’s syndrome t h e outstanding observation in these patients is that despite the lim ited capacity o f phosphorylase deficient m uscle to resynthesize atp, little o r no decline in mus­ cle a t p concentrations has been observed during fatigueing exercise in m cardle’s patients. however there is an abnorm ally large accum ulation o f pi and proba­ b ly o f a d p and a m p and these could contribute to fa­ tigue by inhibition o f intracellular processes involved in muscle contraction. glucose infusion reduces the ex ­ tent to which pi concentrations rise and increases re­ sistance to fatigue. this indicates a m etabolic shift from the creatine kinase (equation 1, below ) and myokinase a m p deam inase coupled reactions (equation 2, below) in which there is net accum ulation o f phosphate, to those o f oxidative phosphorylation and glycolysis in which both a d p and pi are used to resynthesize a tp (lew is and haller, 1986). equation 1 t h e creatine kinase reaction a t p > a d p + pi a d p + pcr > a t p + cr net: pcr > pi + cr equation 2 t h e m yokinase-am p deam inase reaction 2 a t p > 2 a d p + 2pi 2 a d p > a m p + atp a m p > nh 3 + imp net: a tp > 2pi + nh3 + im p thus the abnorm ally large rises in intramuscular pi con­ centrations during exercise in these patients indicates their reliance on the creatine kinase and the myokinase a m p deam inase cou pled reactions to regenerate a t p (equations 1 and 2) rather than o n oxidative m etab o­ lism. t h e detrim ental result is the accum ulation o f in­ creased intracellular pi concentrations which im pair m uscle contraction and cause fatigue. th ere is also evid ence that the rate o f a t p turnover is reduced during fatigue in m ca rd le’s patients indicat­ ing product inhibition o f the rate o f atp hydrolysis this m echanism is thought to explain exercise-induced fa­ tigue also in healthy persons. a decline in skeletal m uscle excitation shown by a fall in the m uscle action potential is also found in these patients. th is could be the result o f product inhibition o f the m em brane na + /k + atpase reaction which can be relieved by the rem oval o f phosphate via gly co gen o l­ ysis in norm al but not in phosphorylase deficient m us­ cle. lewis and haller (1986) conclude that events which limit a tp synthesis in m cardle’s patients also limit atp hydrolysis, thereby slow ing a tp turnover and prevent­ ing m uscle rigor from developing, analogous to the sit­ uation that develops in norm al m uscle during exhaus­ tive, m axim al exercise. thus the bioch em ical basis for fatigue in skeletal m uscle in both norm al and diseased m uscle m ay be quite similar. th ere are two oth er interesting features o f this con ­ dition. first, patients with m ca rd le’s syndrom e show a “ ventilation turnpoint” during exercise indicating that this phenom enon, also known as the “anaerobic thresh­ o ld ” , has no relationship to lactate production by the skeletal muscles. second, patients with m ca rdle’s syndrom e also show a post-exercise o xy g en debt (excess post-exercise o xy­ gen consum ption — epo c). traditional theories have su ggested that the e p o c is due to an excess oxygen consum ption required during the post-exercise recov­ ery period to oxidize the lactate produced during the precedin g exercise. t h e presence o f this ph enom enon in these patients indicates that this cannot b e the cor­ rect explanation. lactate transporter defect fishbein (1986) has recently d escribed the first case o f an intriguing and possibly not uncom m on m uscle dis­ order in which there is an absence o f the lactate trans­ porter in both skeletal m uscle and red b lood cells. th e lactate transporter is b elieved to be a m em bran e pro­ tein that co-transports a lactate anion and a proton e x ­ ternally without a requirem ent for atp. t h e transporter is thought to b e responsible for 9 0 % o f lactate efflux from these cells. its activity is sensitive to the ph gra­ dient across the cell m em brane and increases markedly as the intracellular ph falls (fishbein, 1986). t h e patient described by fishbein was a 26 year old m ilitary drill instructor w ho was investigated for chest pain and coincidentally found to have m arkedly elevat­ ed serum c k activities (up to 13,700 10 — norm al up to 2 00 10) on several occasions. exercise tests revealed that the patient showed elevated b lo o d lactate concen­ trations after exercise and was therefore not suffering from m ca rd le’s syndrom e. however the rate at which his blood lactate concentrations returned to the normal resting levels after exercise was profoundly delayed. laboratory studies confirm ed that the rate o f lactate 8 sa journal o p sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) muscle metabolism release from the patient’s red b lo o d cells was also se­ verely abnorm al. w hilst the patient had no sym ptom s directly attri­ butable to this condition, fishbein suggests that e x ­ trem e exercise in such patients could lead to rhabdo­ m yolysis d ue to their inability to d ecrease intracellular acidosis sufficiently rapidly during and after exercise. th e condition m ay also explain the frequently unex­ plained fin din g o f chronically elevated serum c k ac­ tivities and attacks o f rhabdom yolysis in s o m e appar­ ently healthy individuals. defects of lipid metabolism th e classic disorder o f lipid m etabolism is that due to the absence o f the e n zy m e carnitine palmityltransfer ase (c p t ) in skeletal m uscle. this en zym e is essential for the transport o f lon g chain fatty acids across the in­ ner m itochondrial m em brane for their further m etabo­ lism by beta-oxidation with the production o f acetyl co a which enters the krebs cycle. to date there have been approxim ately 25 subjects with this condition reported in the literature. two have been fem ales. th e inheritance o f the condition is autosomal recessive (an gelini et al 1981). a related condition is m uscle carnitine deficiency. carnitine is also essential for the transport o f fatty acids across the m itochondrial m em brane. carnitine is pro­ duced in the liver and transported to m uscle via b lood from where it is actively absorbed. carnitine deficiency m ay therefore result from the failure o f carnitine syn­ thesis by the liver or b e due to the failure o f carnitine uptake by the muscles. treatm ent with carnitine helps those patients who d o not produce carnitine. m uscle c p t exists in two different form s on the in­ ner (cpt-11) and outer (cpt-1) m itochondrial m em branes it is a deficien cy o f cpt-11 which causes this syndrom e (trevisan et al 1987). sym p tom s o f c p t d eficien cy usually b eg in late in childhood o r in early adulthood. a s in m ca rd le’s syn­ drom e, there are no abn orm alities at rest but fasting m ay cause serum c k activities to rise m arkedly (car­ roll et al 1979). patients are usually able to perform vigorou s exer­ cise without com plications and their vo z max values and cardiovascular function during exercise are normal (lewis et al 1991). this finding indicates the importance o f normal carbohydrate m etabolism for m axim um exer­ cise and for the norm al cardiovascular response to e x ­ ercise. however m uscle tenderness, pain and sw elling m ay occur after very p rolo n ged exercise. cramps m ay also b e a feature o f the condition (b y e and kan, 1988). more gen eralized m uscle sw elling m ay occur when exercise follows a bout o f p rolo n g ed fasting o r after a period on a low carbohydrate, high fat diet. muscle pain and swell­ ing are accom panied by very m arked elevations in se­ rum enzym e activities and in myoglobinuria. there may also be acute renal failure. patients with this condition are dependent on carbo­ hydrate to provide their en ergy requirements during ex­ ercise. thus they bum carbohydrates m ore rapidly than usual during exercise and m ay d evelop rh abdom yoly­ sis when m uscle g ly co gen d ep letion occurs. prevention o f com plications is therefore through the prescription o f a high carbohydrate diet to maintain muscle and liver gly co gen concentrations. t h e condition can be diagn osed with m uscle biopsy which confirm s the absence o f c p t activity. lipid-filled vacuoles m ay be shown predom inantly in type 1 fibres; they are esp ecially m arked in the form o f this con d i­ tion which results from carnitine deficien cy (b y e and kan, 1988). defects of mitochondrial function syndromes associated with excessive lactate formation in these patients there are deficien cies in o n e or m ore o f the enzym es o f the electron transport chain; in som e patients no defect has yet been identified. th e effect o f these abnorm alities is to reduce the capacity for o x ­ idative a t p production and therefore to increase reli­ ance on glycolytic a tp production with increased rates o f lactate and pyruvate production and the associated severe m etab olic a cid osis t h e clinical features com m on to all these conditions are extrem e exercise intolerance associated with early fatigue, m u scle weakness and dyspnoea. t h e patients respond to acute exercise as if they were extrem ely un­ fit. s o m e patients have high resting b lood lactate con ­ centrations; however in all, there is a steep increase in b lo od lactate concentrations at very low levels o f exer­ cise. in co m m on with patients with m ca rd le’s syndrom e these patients also show very low v 0 2max values and an abnorm al cardiovascular response to m ild exercise including a disproportionate cardiac output, tachycardia and ventilation for the appropriate m etabolic rate (haller et al 1989). t h e m etab olic basis for this is presum ably the sam e as that in m ca rd le’s syndrom e, that is in­ creased intramuscular pi concentrations due to an ab­ normal reliance on the creatine kinase and myokinase a m p deam inase cou pled reactions to regenerate a tp in muscles which have an impaired capacity to produce a t p by oxidative m etabolism . th e inheritance o f these conditions is unique because the m itochondrial d n a , which c od es for the 13 protein com pon ents o f the electron transport chain, is trans­ m itted exclusively by the m oth er (jones and round, 1990). th is su ggests that the m o th er m ay have an in­ ordinate influence on the child’s ability to produce a tp by oxidative pathways (and therefore to becom e a cham ­ pion athlete?). defects of adenine nucleotide metabolism myoadenylate deamine deficiency (md) th e enzyme m yoadenylate deam inase (m d ) hydrolyzes the breakdown o f a m p (produced by the m yokinase re­ action) to am m on ia and im p (e quation 2). a bsen ce o f this en zym e is on e o f the com m on est o f the known m uscle en zym e defects and exists in two form s — the prim ary type which is inherited as a com p lete gen e block in an autosom al recessive pattern and the secon­ dary type which results from m uscle d a m a g e due to other diseases (fishbein, 1985). sa journal of sports medicine september 1994 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) muscle metabolism the enzyme defect is believed by some to explain cramping and exercise intolerance in some individuals, usually in adult to middle-age (fishbein, 1985). larger studies, however, have failed to shown any association between symptoms and this enzyme defect (mercelis et al 1987). it may be that this is an enzyme defect still searching for a disease! references angelini c, fneddo l, banistella p, et al. carnitine palmityl tranferase deficiency: clinical variability, carrier detection and autosomal reces siue inheritance. neurology 31: 883-886, 1981. ^ bye ame, kan ae. cramps following exercise. aust paediatr j 24 258-259, 1988. carroll je, devito dc, brooks mh, planer gj, hagberg jh. fasting as a provocative test in neuromuscular disease. metabolism 28: 683-687, 1979. fishbein wn. lactate transporter defect: a new disease of muscle. science 234: 1254-1256, 1986. fishbein wn. myoadenylate deaminase deficiency: inherited and ac­ quired forms. btochem med 33: 158-169, 1985. haller rg, lewis sf, estabrook rw, dimauro s, servidei s, foster dw. exercise intolerance, lactic acidosis, and abnormal cardiopulmo­ nary regulation in exercise associated with adult skeletal muscle cytochrome oxidase deficiency. j clin invest 84: 155-161, 1989. jones da, round jm. skeletal muscle in health and disease. man­ chester university press, 1990. kono n, mineso i, sumi s, shimizu t, kang j, nonaka k, tarui s. metabolic basis of improved exercise tolerance: muscle phosphory­ lase deficiency after glucagon administration. neurology 34: 1471-1476, 1984. lewis sf, haller rg. the pathophysiology of mcardle's disease: clues to regulation in exercise and fatigue. j app physiol 61: 391-401, 1986. lewis sf, vora s, haller rg. abnormal oxidative metabolism and o transport in muscle phosphofructokinase deficiency. jappl physiol 71: 391-398, 1991. mcardle b. myopathy due to a defect in muscle glycogen breakdown. clin sci 10: 13-33, 1951. mercelis r, martin jj, de barsy t, van den berghe g. myoadenylate deaminase deficiency: absence of correlation with exercise intoler­ ance in 452 muscle biopsies. j neurol 234: 385-389, 1987. pryor sl, lewis sf, haller rg, et al. impairment of sympathetic acti­ vation during static exercise in patients with muscle phosphory­ lase deficiency (mcardle's disease). j clin invest 85: 1444-1449, 1990. trevisan cp, isaya g and angelini c. exercise-induced recurrent myo­ globinuria: defective activity of inner carnitine palmitoyltransferase in muscle mitochondria of two patients. neurology 37: 1184-1188, 1987. wahren j, felig p, havel rj, jorfeldt l, pernow b, saltin b. amino acid metabolism in mcardle's syndrome. n engl j med 288: 774-777, 1973. □ letters to the editor readers’ letters concerning articles in the journal are invited, and will be forwarded to our editors for consideration for publication. please post to: glenbarr publishers c.c. 25 — bom pas road dunkeld 2 1 9 6 w i1 5 e n a c h 9 3 0 6 2 5 e ®|vouanents tabl ets diclophenac sodium 7 5 mg m m v* geigy 10 sa journal o f sports medicine september 1994re pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) muscle proteins and the contractile properties of muscle fibres kathryn h myburgh phd introduction muscles are machines which provide the power that is the basis for all vertebrate movement. the mechanical properties o f an active muscle are dependent on many factors such as the shape and size o f the whole mus­ cle, its fibre type, fibre size and length, and the angle o f the fibre-tendon attachment, as well as a variety of neural factors including cortical drive and m otor unit recruitment patterns. however, the force originates at the molecular level from the interaction o f the major muscle proteins, actin and myosin, in the presence of atp and ca + + . this review will outline some o f the major discoveries which led to the theories of the mechanism o f force production at this level in skeletal muscle, including the roles played by atp and ca + + , and the relationship between force and velocity. it will then discuss factors within a single muscle fibre which influence these contractile properties and which are of particular relevan ce to ex ercise scientists. i. the mechanism of force production our current understanding o f the mechanism o f force production is based in large part on 3 discoveries made in the 1950’s at that time the band-like structure of muscle was already well described even at the level of the sarcomere, but the function o f the bands was not known. two important discoveries linking the structure of the sarcomere to its function were (i) that the pattern of the bands is caused by thick and thin filaments1 and (ii) that in those bands where the two types o f fila­ ments overlap, they also interact at regular intervals by means o f bridges.2 the third discovery, which was made at the same time by two different investigators and was published in the same edition o f the presti­ gious journal nature, was that the filaments themselves do not shorten during contraction. instead, they appear to slide between one another so that the amount by which they overlap increases during active shortening in a contracting muscle.34 these results led to the for­ mulation o f the sliding filament theory o f cross-bridge interaction during muscle contraction.5 huxley pro­ posed that force was produced by each projection from the myosin thick filament as it attached to the actin fila­ ment and that the force was related to the kinetic ener­ gy available in the cross-bridge before attachment.5 more than a decade later following many more mechan­ ical experiments performed at faster time resolutions and employing very accurate, quick changes in ten­ sion6 or length,7 huxley and simmons8 formulated a mrc/c1ct bioenergetics o f exercise research unit (jct medical school observatory 7925 second proposal for the mechanism o f force generation by the actomyosin cross-bridge. in the second model, it was proposed that force is generated shortly after at­ tachment as the cross-bridge changes to a more sta­ ble configuration (see fig. 1: 3a and 3b). this hypothe­ sis requires that the attached cross-bridges exist in two or more configurations (see fig. 1: 1, 3a and 3b) and that the head can rotate from a 9 0 ° angle to a 45° an­ gle (fig. 1: 3a to 3b). indeed, a 4 5 ° orientation o f the cross-bridges had already been shown in electron micrographs o f rigor muscle,9 and there was no rea­ son to believe that the cross-bridge could not rotate through that orientation during a contractile cycle. m a-m figure 1. a schematic representation o f a t p hydrolysis, release o f the products o f atp hydrolysis and actomyosin interaction during the contractile cycle. abbreviations: a = actin; m = myosin; a -m = actomyosin complex; atp = adenosine triphosphate; a d p = adenosine diphos­ phate; pi = inorganic phosphate. steps: 1 cross-bridge attachment; 2 = phosphate release; 3a and 3b con­ figurational changes; 4 = a d p release; 5 = a tp bind­ ing; 6 = cross-bridge detachment; 7 = a t p hydrolysis. ii. the role of atp in the cross-bridge t^cle while physiologists and physicists were piecing toge­ ther the structural and mechanical data, biochemists were actively investigating the kinetics o f atp hydroly­ sis by an atpase enzyme which is part o f the myosin molecule. it had already been discovered in 1939 that the major muscle protein complex, actin-myosin, (also termed actomyosin), catalysed the hydrolysis o f atp.10 it was not until 1971 that a scheme was presented by lymn and taylor11 which integrated the steps in the chemical splitting o f atp to ad p and pi, with a cycli­ cal attachment and detachment o f actin and myosin. sa journal of sports medicine september 1994 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) muscle fibres in short, a t p hydrolysis occurs before m yosin attaches to actin (f ig. 1: 7), this is follow ed by attachm ent and form ation o f the actom yosin-ad p-pi com p lex (fig. 1: 1). a fter release o f the hydrolysis products, pi and a d p (fig. 1: 2 and 4), actin and m yosin rem ain associated (fig. 1: a-m), probably with the cross-bridge head at an angle o f 45°. actin and myosin dissociate with the bind­ ing o f a t p to m yosin (fig. 1: 5 and 6), and once again, a t p hydrolysis occurs in the detach ed state (fig. 1: 7). it on ly b ecam e apparent later that pi is released in a separate step before the release o f a d p 12 and that the actomyosin-adp-pi com plex (fig. 1: 1) is relatively weak and produces less force than th e subsequent strong binding actom yosin-ad p co m p lex (fig. 1: 3 b ).13 iii. the role of ca++ in the cross-bridge cycle biochem ical studies o f actomyosin-atp hydrolysis done in solution have highligh ted different properties o f the m yosin-atpase enzym e. for exam ple, unlike whole muscle which requires both a tp and c a++ to contract, a mixture o f purified m yosin and purified actin can hy­ drolyse a t p without the presence o f c a ++ in the so­ lution.14 this indicated the presence o f an additional protein, or proteins, that could inhibit the cross-bridge cycle unless calcium was present to rem ove that inhibi­ tory action. th ese proteins were identified as tropom yo­ sin and the troponin -com plex1516 and b ecam e known as regulatory proteins. a very important early discovery which m ade it possible to define the role o f c a ++ on actual force production in the cross-bridge cycle, was the developm ent o f the so-called “skinned” fibre. by in­ cubating a m uscle fibre in a solution containing 50% glycerol, the m em brane is m ad e perm eab le to ions, sm all m olecu les and even larger m olecules.17 t h e ini­ tiation o f contraction in the skinned fibre is no longer dependent on m em brane depolarisation, but is under control o f the investigator, and is achieved by the addi­ tion o f calcium to the solution bathing the fibre. it was later discovered that the level o f force production, meas­ ured by a force transducer to which on e end o f the skinned fibre is attached, could be varied by varying the concentration o f free calcium .18 t h e characteristic relationship betw een force and calcium ion concentra­ tion (see fig. 2 ) shows that force is n eglig ib le at pca 6 (= 1 0 -6 m c a ++) and m axim al around pca 4 (= 1 0 ~ 4 m c a ++). t h e sigm oid al shape o f the curve indicates that few cross-bridges attach initially, but that there is a large coop erative action betw een adjacent myosin binding sites on actin, so that force increases steeply from approxim ately pca 5.5. iv. the force-velocity relationship w hen a skinned fibre is attached to a force transducer on one side and a very rapid servo-controlled m otor arm on the other, it is possible to vary the tension in the fibre by varing the position o f the m otor arm and hence the length o f the fibre. t h e shortening velo city can be determ ined at specific fractions o f the m axim um ten­ sion by several load clam ps in which the tension in the fibre is released to specified levels o f subm axim al ten­ sion and the velocity o f tension redevelopm ent is m eas­ ured. t h e data can b e fitted to the hill equ ation 19 and the maximal velocity o f shortening (vmax) is calculated p c a figure 2. the characteristic relationship between force and calcium ion concentration. abbreviation: pca = negative log of calcium concentration in moles e.g. pca 6 = 70~6 m c a +*. from an extrapolation o f the data to 0 load/0 a cha­ racteristic hyperbolic curve is obtained (see fig. 3) showing how the velo city o f contraction is m axim al when the load (p) is equal to 0, and slows down as p increases until the velo city is 0 at m axim al load (po). a t this point, no shortening occurs and po is analogous to m axim u m isom etric force. ti -o force (p/po) figure 3. the characteristic relationship between force and velocity o f contraction. abbreviations: p = force; po = maximum force. v. the effect of muscle fibre type on the mechanics of contraction v.i the characteristics of the basic fibre types t h e basic characteristics o f the contractile cycle d e ­ scribed a bove apply to all m uscles with the banded sar­ com ere structure. but, in 1873 the french physiologist, 12 sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) muscle fibres ranvier, noted that red and white skeletal m uscles have different contractile properties: red m uscles contract slowly, w hile white m uscles contract and relax rapid­ ly.21 this apparently sim p le observation set the stage for num erous physiological, biochem ical and h istolog­ ical studies which aim ed to defin e the properties o f different m ucles and m uscle fibre types. in mammals, w hole m uscles are generally com posed o f various fibre types. th is h eterogen eity com plicates research studies, but allows for a great deal o f physio­ logical variation. fortunately, in sm aller m am m als such as mice, rats and cats, the soleus is com p osed alm ost entirely o f red m uscle fibres and the extensor digito rum longus o f white fibres. th is m ade it quite sim ple for electrophysiological studies to determ ine clear differ­ ences betw eent those m u scle groups in the properties o f a single twitch contraction and led to general accep­ tance o f the term s slow-twitch and fast-twitch fibres.22 a t around the sam e tim e biochem ical studies showed that the myosin from fast-twitch fibres hydrolysed a tp much faster than did the myosin from slow-twitch mus­ cle23 and histochem ists were able to differentiate b e­ tween different myosin atpase types (isozym es) due to their differing susceptibility to losing their enzym atic activity at different ph’s.24 (s ee table 1). a n o th e r ap­ proach was to differentiate betw een the fibre types by determ ining either their resistance to fatigue during im ­ posed stim ulation,25 the num ber o f m itochondria pre­ sent and the oxidative en zym e capacity,26’27 or the g ly ­ cogen co n ten t28 in these ways it was m ade possible to draw up a table o f basic fibre typ e classifications (see table 1). interestingly, it was found that all the m uscle fibres activated by the sam e m o to r unit fit into the sam e his tochem ically determ in ed classification o f fibre type.25 however, the follow ing question arises: can the contrac­ tile characteristics o f each fibre type b e ascribed to a com bination o f the neural activation process and the m etabolic characteristics, or d o the contractile proteins them selves also exert an independent influence? t h e single skinned m uscle fibre is the perfect exp erim en ­ tal m o d el to answer this question since, as m entioned before, the activation is controlled by the investigator. t h e follow ing paragraphs will consider whether fibre type affects peak isom etric force production, velocity o f contraction and the force-pca curve irrespective o f neural control. v.ii contractile properties o f the basic fibre ty p e s early experim ents on a large range o f muscle types and sizes showed that the m axim al force was related to the cross-sectional area o f the m uscle.29 fibre diam eters o f single m uscles fibres can vary up to 10-fold. t h ere­ fore, measurements o f force or tension must be correct­ ed for cross-sectional area, before differences inherent in the m uscle proteins can be discovered. early reports found that there w ere no differences in the m axim al force (po) when expressed relative to the cross-sectional area o f slowor fast-twitch m uscles30 o r fibres dissect­ ed from purely slow-, or purely fast-twitch m uscles31 (see fig. 3: both type 1 and 11 have the sam e po). in skinned fibres the data on m axim al values o f force per unit o f cross-sectional area in different fibre types are ta b l e i basic s keletal m u scle fibre ty p e classification s skeletal muscle fibre types n om enclature type 1 11a iib slow fast oxidativefast oxidative gly co lytic glycolytic s o f o g fg characteristics: colour red red white twitch slow fast fast a tpase activity low high high lost at ph 9.4-10.4 4.4-4.6 4.4 g lycogen content low high high fatigue resistance high high high oxidative capacity high high low not consistent and range from indicating no significant difference,32 to higher values in slow-twitch fibres,33 or higher values in fast-twitch fibres.34 data from human biopsy sam ples w ere in agreem en t with the latter fin d­ ings.35 t h ese discrepancies are m ost likely due to difficulties in the m easurem ent o f the cross-sectional areas o f sin gle fibres. t h e fibre diam eter is not always consistent a lon g the length o f a fib re which has been attached to a force transducer and a sm all error in the m easurem ent o f d iam eter is m ag n ified in the calcula­ tion o f cross-sectional area. however, further technical advances have reopened this question and it is currently under investigation in several laboratories. a lth ou gh the issue o f m axim al force production by different fibre types is not resolved, it is currently ac­ cepted that there are m ost likely no differences between fibre types o f healthy m uscle and this observation is explained by assuming that the num ber o f cross-bridges per unit area o f m uscle is consistent36 and that the force per cross-bridge is the same. a s m entioned in sec­ tion 1, cross-bridges can b e in either a weak, low force (actom yosin-ad p-pi) (see fig. 1: 1) or a strong, high force (actom yosin-ad p) state (see fig. 1: 3b). t h e rela­ tive proportion o f each state could therefore also in­ fluence force production. recent m echanical data sug­ gest that during a m axim al isom etric contraction in a previously rested muscle, the m ajority o f the cross bridges are in the strong-binding state.37 but when m uscle is fatigued and the intracellular pi concentra­ tion is high, m ore cross-bridges are in the weak-binding state and force can be reduced by as much as 3 0 % .20 a lthou gh peak isom etric force is apparently sim ilar in both fibre types, the force develop ed at subm axim al c a ++ concentrations is different for fastand slow twitch fibres o f the rat.33’38 slow-twitch fibres could produce low levels o f force at significantly lower con ­ centrations o f c a++ than fast-twitch fibres. however, a steeper slope o f the force-pca curve in fast-twitch fibres indicate that once the c a ++ concentration threshold for force developm ent has been reached the fast-twitch fibres develop peak force at a faster rate. t h ese obser­ vations can b e attributed to differences in the calcium sensitivity o f different isoform s o f the regulating prosa journal of sports medicine september 1994 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) tein, troponin.38-39 it is interesting to note that the myo­ sin and troponin isoforms change after complete inac­ tivity and weightlessness induced by hind limb susperv sion in a rat model and revert to faster isoforms. indicates that even adult muscle proteins are continu­ ously regulated to adapt to environmental changes as mentioned before, the broad division of fibres into fastand slow-twitch types is based on their speed contraction. maximal shortening velocity (vmax) can be as much as 6-fold higher in fast glycolytic fibres com ­ pared with slow oxidative fibres, while the fast, oxida­ tive fibres have a vmax only 3-fold higher (see fig. 3 ) 33 in addition, the shape o f the force-velocity curve is more concave for slow-twitch fibres than fast-twi ch fibres indicating that even at a specific fraction of the maximal force, the velocity is slower in the slow-twitch fibres.34 since the fibres are already fully activated, these differences are unrelated to ca + + concentration or ca++ sensitivity and can therefore be ascribed to the contractile proteins themselves. v.iii further division o f fibre type based on contractile protein subunits . e v e n though the classification of fibre types in table i is not simple, for a number of r e a s o n s there are not sufficient categories to take into account all the differ ences that are now a p p a r e n t b e t w e e n m u s c ^ ir e s instance, a type i1c fibre, which can be placed between type 11a and i1b in characteristics was identified in 1970.24 within a decade, improvements in histoch ical techniques suggested that there were also another muscle fibres two distinct subtypes of fast-twitch fibres named iiac and 11ab.41 also, comparisons o f biochemical and tochemical classification has shown that types ua and ub fibres do not always c o r r e s p o n d to the fog and l-<j s * n * further suggesting that the basrc f.bre classification scheme in table 1 is too simplistic. this diversity is perhaps not surprising, when one considers that the myosin molecule is a la^9e “ ^ p0 molecule with several subunits, any of which may oc­ cur in slightly different forms (isoforms). two heavy poly_ peptide chains form the thick filament or backbone of myosin and also extend into the neck region and the globular heads which together form t h e cross^bndges between the myosin backbone and the actin fila­ ment 43 the portions o f the two heavy chains which make up the head region contain the myosin atpase enzyme subunit. the two heads each also contain two different light polypeptide chains so that the entire myosin molecule has 6 subunits.43 staron and pette have done several elegant experiments w h i c h combmed histochemical atpase staining followed by micro­ dissection o f each o f the various fibre types into smal pieces which were then analysed biochemically by gel electrophoresis for the presence of different myosin heavy chain isoforms.44-45 these studies showed that there are three different myosin heavy chain isoforms which are named type 1, type haandtype nbsm cethey correlate with histochemically identified type i, type 11a and type ub fibres. type iiab fibres, which ^ ^ c o n ­ tinuum of atpase staining intensities between type 1ia and ub, contained both type ita and type lib myosin r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) heavy chains45 the presence of both types of fast myosin heavy chains has also been shown by several other groups in rat and human muscle.4647 it has re­ cently suggested that the type iiab fibres can be broken down into type uab (containing predominantly type ila heavy chains), type iiab (containing 50-50 type 11a and b heavy chains) or type ilab (containing predominant­ ly type lib heavy chains).48 for the exercise scientist an important question arises at this point: are these more subtle histochemi cal and biochemical differences really functionally sig­ nificant? v.iv relationships betw een contractile properties and contractile protein subunits reiser et al49 tested the relationship between myosin heavy chain composition and maximal shortening velo­ city in rabbit soleus the majority of the soleus fibres contained only the slow heavy chain isoforms and con­ tracted with a low vmax. a few fibres which had signi­ ficantly higher vmax values had differing proportions o f slow and fast myosin heavy chain isoforms, and the greater the proportion o f the fast isofbrm, the higher the vmax values obtained. this study did not subdi­ vide the fast myosin heavy chain into the ila and lib iso­ forms. however, recently a rat study which combined mechanical measurements with immunocytochemical staining with 6 different myosin heavy chain antibodies, identified type i, type iia and type iib fibres as well as another fibre type which they named type iix (see ta­ ble ii).34 as expected, type i fibres had significantly slower maximal shortening velocity than any o f the fast fibre typ es based on average values type iib were the fastest and significantly faster than either type iix or type i1a. the range o f vmax values for type iia, iib and iix fibres overlapped considerably, and the authors sug­ gested that differences in the isoforms of the myosin light chain subunits could be responsible for additional regulation o f the maximal velocity of contraction. in­ deed, greaser et al39 had previously shown in rabbit plantaris (mixed fibre type composition), that myosin light chain composition significantly influenced the vmax of the fast fibres in short, all the slow velocity fibres contained only slow isoforms o f light chain; the fibres in the group with highest velocities contained only fast isoforms o f both heavy and light chains; the group with intermediate velocities had various com bi­ nations o f fast and slow isoforms of both heavy and light chains. v.v contractile protein subunits in human skeletal m uscle another important issue from the point o f view o f the exercise physiologist, is whether the findings in animal studies are relevant to human muscle. as noted earlier, rat muscle contains an extra distinctive fast fibre, name­ ly the type iix,34 which is not present in either rabbit or human muscle. but histochemical and biochemical studies on human muscle biopsy samples have shown heterogeneity within the broad classifications o f fibre types biopsies obtained from the vastus lateralis of healthy men showed that the slow-twitch fibres con­ tained only slow myosin heavy chains but light chains of both the slow and fast isoforms, although the slow muscle fibres leader of the p a c k when you need pain-killing power to get there first. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) isoform s predom inated (see table 11).50 furthermore, the histologically classified fast typ e 11a fibres (shown in the rat to have intermediate m axim al shortening velo­ cities34) contained predom in antly a different light chain isoform than did the fast type 11b fibres (as was also found in the rat). th ese histochem ical and bioche­ mical results are also very sim ilar to those found in the study o f the rabbit plantaris a m uscle o f m ixed fibre type.39 a lth ou gh wada et al50 did not do m echanical m easurem ents on their human m uscle fibres, one would expect that their contractile properties would also dem onstrate the continuum o f shortening velocities correlating with the bioch em ical com position o f the myosin m o lecu le subunits which was shown in the anim al studies. table ii heterogeneity of skeletal muscle typed by histological methods or by biochemical analysis of contractile protein composition skeletal muscle fibre divisions histological typing: slow-twitch: fast-twitch: 1, 1c ha, 11ac, 11c, iiab, 11x* 11b b iochem ical typing: — m yosin heavy chain 1 ha, 11au (mhc): hab, 11x*, 11b — m yosin light chain mostly: mostly: (m lc): is, 2s if, 2f, 3 f also: lf-3 f also: is, 2s * rat muscle only __________________ vi. current research issues it is therefore apparent that m u scle contractile protein com position is even m ore h eterogeneou s than was pre­ viously believed. t h e cause o f this heterogen eity is alm ost certainly a com bination o f both gen etic and en­ vironm ental factors t h e relative im portance o f each of these m echanisms is a current issue in the field o f skele­ tal m uscle research, and there is no doubt that interest­ ing inform ation will soon b ec om e available. another is­ sue currently under investigation is the effect o f train­ ing on m uscle histology and m uscle contractile protein isoform s a recent human study reported the c o m p o ­ sition o f a biopsy o f the vastus lateralis o f a highly strength-trained wom an.52 in addition to the usual type 1,11a, and ub fib re s there was a distinctly different set o f c-fibres which com prised 15% o f the total num ber o f fib re s t h e biochem ical data revealed that even the c-fibres had sub-types (1c, 11c and uac) which could be distinguished by the ratios betw een the different iso form s o f myosin heavy and light chains which they con­ tained. t h e authors suggested that these fibres were either specifically adapted and existed as a distinct population o f fibres in highly trained muscle, or they were in the process o f bein g transform ed from fast to slow fibre types. in a rat study, w here the plantaris was overloaded by surgical rem oval o f the m edial gastroc­ nem ius and the s o le u s d iffee et al52 showed that the myosin heavy chain com position changed from pre­ dom inantly fast to about 2 5 % slow isoforms. t h e e f­ fects o f m ore dynam ic exercise on contractile protein isoform com position has not yet been investigated. vii. implications for sport variability in athletic potential between individuals can, at least in part, be traced to h eterogen eity o f the con tractile proteins th e m selv es t h e adaptations o f skele­ tal muscle to exercise training include m ore than hyper­ trophy, im proved resistance to fatigue and ch anges in en zym e activity and substrate utilisation. it is as yet unknown exactly how different types and quantities of training influence the contractile protein com position and to what extent their m echanics can b e changed. however, these issues provide a ch allenge to research­ ers in this area. conclusion t h e diversity o f m am m alian skeletal m uscle is due in part to both obvious as well as m ore subtle m olecular differences in the contractile proteins t h ese are charac terisable histochem ically and b ioch em ically and there is abundant evidence that these differences influence the m echanics o f contraction o f the individual muscle fib res it is appropriate to m ention again that we have not even considered differences which exist in the ar­ chitecture o f the w h o le m uscle or the activation o f the m otor units w e have also paid little attention to the enzym atic and substrate content o f the m uscle fibres, except as these directly influence their histochem ical classification. nevertheless this paper has described the m olecular basis o f m uscle contractile protein hetero­ g en eity and its functional consequences (see table 111 for summary). given all these c om p lexities it is not sur­ prising that quantitative differences exist in the m us­ cular capacity o f athletes particularly elite a thletes and we suggest that these differences can be traced to the contractile proteins them selves. in addition, with this inform ation at hand, it is now possible to investigate m ore system atically the adaptation o f m uscle proteins to environmental influences such as increased or altered exercise training re gim e n s table iii: a summary of mechanical and biochemical properties of skeletal muscle fibres • m axim al force production is related to cross sectional area in intact m uscle as well as in sin­ g le fibres in vitro • m axim al shortening velocity can be as much as 6-fold higher in fast gly colytic fibres com pared with slow oxidative fibres • myosin is a large m o lecu le with 6 subunits, all o f which m ay occur in different isoform s • t h e m yosin heavy chain isofbrm regulates m ax­ imal velocity o f contraction • th e m yosin light chain isoform is responsible for additional regulation o f the m axim al velocity o f contraction • myosin isoform s ch an ge after inactivity indicat­ ing that adult m uscle fibres adapt to environm en­ tal influences sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) muscle fibres references 1. huxley he. electron microscope studies of the organisation o f the filaments in striated muscle. biochimica et biophysica acta 1953 12: 387-394. 2. huxley he. the double array o f filaments in cross-striated mus­ cle. j biophys biochem cytol 1957; 3: 631-648. 3. huxley af, niedergerke r. interference microscopy o f living mus­ cle fibres. nature, lond 1954; 173: 971-973. 4. huxley he, hanson j. changes in the cross-striations o f muscle during contraction and stretch and their structural interpretation nature, lond 1954; 173: 973-976. 5. huxley af. muscle structure and theories o f contraction prog bi­ ophys chem 1957; 7: 255-318. 6. civan mm, podolsky 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eisenberg e, greene l. the relation o f muscle biochemistry to mus­ cle physiology. ann rev physiol 1980; 42: 293-309. 15. ebashi s, kodama a. interaction o f troponin with f-actin in the presence o f tropomyosin. j biochem tokyo 1966; 59: 425-426. 16. greaser ml, gergely j. reconstitution o f troponin activity from three troponin components. j biol chem 1971; 246: 4226-4233. 17. szent-gyorgyi a. free-energy relations and contractions o f ac, tomyosin. biol bull woods hole mass 1949; 96: 140-161. i ' 18. heilman dc, podalsky rj. force measurement in skinned mus­ cle fibres. j physiol lond 1969; 200: 807-819. / 19. hill av. the heat o f shortening and the dynamic constants o f mus­ cle. proc royal soc lond (b ) 1938; 126: 136-195. 20. cooke r, franks k, luciani gb, pate e. the inhibition o f rabbit skeletal muscle contraction by hydrogen ions and phosphate j physiol lond 1987; 395: 77-97. 21. ranvier ml. proprietes et structures differentes des muscles rouge et des muscles wanes, chez les lapins et chez les raies. com ptes rendus des academie de sciences 1873; 77: 1030-1034. 22. close rl. dynamic properties o f mammalian skeletal muscles physiol rev 1972; 52: 129-197. f 23. bamny m. atpase activity of myosin correlated with speed of mus cle shortening. j gen physiol 1967; 50: 197-218. x v <7 n < t 24. brooke mh, kaiser kk. three myosin adenosine triphosphatase systems: the nature o f their p h lability and sulphydryl dependence j hlstochem cytochem 1970; 18: 670-672. 25. burke re, levine ew, tsairis p, zajae fe. physiological types of histochemical profiles in motor units of the cat gastrocnemius j physiol lond 1973; 234: 723-748. 26. noyikoff ab, shin w-j, drucker j. mitochondrial localization of oxidative enzymes: staining results with two tetrazolium salts j biophys biochem cytol 1961; 9: 47-61. 27. peter jb, barnard rj, edgerton vr, gillespie ca, stempel ke. metabolic profiles o f three fiber types o f skeletal muscle in guinea pigs and rabbits. biochemistry 1972; 11: 2627-2633. l’ ku3etber9 £ histochemical composition, distribution of fibres and fatigability o f single motor units. anterior tibialis mus j q the ra t j neurol neurosurg psychiatry 1968; 31: 424-433. l nowlt° n <~*<~' hines hm. the effects o f growth and atrophy upon the strength of skeletal muscle. a m j physiol 1 9 3 9 /4 0 ; 128: 521-525. 30. close rl. properties of motor units in fast and slow skeletal mus­ cle o f the rat. j physiol 1967; 193: 45-55. 31. sexton aw, gersten jw. isometric tension differences in fibers of red and white muscles. science 1967; 157: 199-202. 32. donaldson skb, hermansen l. differential direct effects of h * on ca2* -activated tension generation o f skinned fibers from the soleus, cardiac, and adductor magnus muscles of rabbits. pfluaers arch 1978; 376: 55-65. 33. gardetto pr, schluter jm, fitts rh. contractile function o f single fibers after hindlimb suspension. j a ppl phusiol 1989■ 66 2739-2749. 34. bottinelli r, schiafftno s, reggiani c. force-velocity relations and myosin heavy chain iso form composition o f skinned fibres from rat skeletal muscle. j physiol, lond 1991; 437: 655-672. 35. fitts rh, costill dl, gardetto pr. effects o f swim exercise train­ ing on human muscle fiber function. j appl physiol 198966 465-4 75. fitts rh, mcdonald ks, schluter jm. the determinants o f skele­ tal muscle force and power: their adaptability with changes in ac­ tivity pattern. j biomech 1991; 24(suppl 1): 111-122. 37. metzger jm, m oss rl. p h modulation o f the kinetics o f a ca* * -sensitive cross-bridge state transition in mammalian single skeletal muscle fibers. j physiol, lond 1990; 428: 7551-7564. 38. metzger jm, m oss rl. greater h * ion-induced depression o f ten­ sion and velocity in single skinned fibers of rat fast versus slow muscles. j physiol, lond 1987; 393: 727-742. 39. greaser ml, m oss rl, reiser pj. variations in contractile proper­ ties of rabbit single muscle fibres in relation to troponin t isoforms and myosin light chains. j physiol 1988; 406: 85-98. 40. campione m, ausoni s, guezennec, schiafftno s. myosin and troponin changes in rat soleus muscle after hindlimb suspension j appl physiol 1993; 74(3): 1156-1160. 41. ingjer f. effects of endurance training on muscle fibre atpase ac­ tivity, capillary supply and mitochondrial content in man. j phusiol 1979; 294: 419-432. 42. greene hj. muscle power: recruitment, metabolism and fatigue. in human muscle power (eds. nl jones, n mccartney and a j mccomas). champaign, illinois: human kinetics, pp 65-79, 1986. 43. cooke r. the mechanism o f muscle contraction. c r c crit rev biochem 1986; 21: 53-118. ^ 44. staron sr, pette d. correlation o ss ^ ^ tttx y o ^ s ^ ^ t p ^ a se ac­ tivity and myosin heavy chain composition in rabbit muscle fibres. histochemistry 1986; 86: 19-23. 45. staron sr, pette d. the multiplicity o f combinations of myosin light chains and heavy chains in histochemically typed single fibies. rabbit tibialis anterior muscle. biochem j 1987; 243: 695-699. 46. danieli-betto d, zerbato e, betto r. type i, ila and lib myosin heavy chain electrophorectic analysis o f rat fibres. biochem biophys res commun 1986; 138: 981-987. 4 7. biral d, betto r, danieli-betto d, saluiati g. myosin heavy chain composition o f single fibres from normal human muscle. biochem j 1988; 250: 307-308. 48. staron rs. correlation between myofibrillar atpase activity and myosin heavy chain composition in single human fibers. histochemistry 1991; 96: 21-24. 49. reiser pj, m oss rl, giulian gg, greaser ml. shortening veloci­ ty in single fibres from adult rabbit soleus muscles is correlated with myosin heavy chain composition. j biol chem 1985■ 260 9077-9080. 50. wada m, katsuta s, doi t, funo s. favourable associations be­ tween myosin heavy-chain and light-chain isoforms in human skeletal muscle. pflugers arch 1990; 416(6): 689-693. 51. staron rs, hikida rs. histochemical, biochemical and ultrastruc tural analyses o f single human muscle fibers, with special refer­ ence to the c-fiber population. j histochem cytochem 1992 40(4): 563-568. 52. diffee gm, mccue s, larosa a, herrick re, baldwin km. inter­ actions o f various mechanical activity models in regulation o f m y­ osin healvy chain isoform expression. j appl phusiol 1993■ 74(5)■ 2517-2522. sa journal of sports medicine september 1994 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) delayed-onset-muscle-soreness m l l a m b e rt and s c d en n is introduction muscle soreness that occurs during intense exercise is most often caused by muscular compression o f capil­ laries and hence an inadequate blood flow within the contracting muscle. the resulting accumulation of pro­ tons, phosphate ions and nucleotides arising from in­ adequate removal o f the products o f energy production, all stimulate pain receptors in the muscle (jones and round 1990). once the exercise is terminated, this acute muscle soreness subsides rapidly. teleologically, it may be argued that such pain occurs as a “ back-up” to the rapid fatigue that prevents the muscles from becom ­ ing irreparably damaged by critically depleting the energy stores that are vital for muscle relaxation. another form o f muscle soreness occurs several hours after the end o f exercise. this condition is charac­ terised by discomfort or pain in skeletal muscle with even modest muscular exertion. the pain is first evi­ dent several hours after the cessation of exercise, peaks 24-72 hours later and subsides after 5 to 7 days the pain is elicted when the muscle is pressed, contracted or stretched. the pain, in contrast to the acute pain that occurs during exercise, is known as delayed-onset muscle-soreness (doms). although doms can be caused by stretching a muscle and by isometric and concentric muscle contractions, it occurs most com ­ monly after eccentric contractions when muscles are used in a breaking motion (ebberling and clarkson, 1989). theories of doms several theories have been proposed to explain doms. the two most common theories are the metabolite ac­ cumulation theory and the muscle damage theory. (1) m etabolite accum ulation theory for d o m s although no longer supported by any scientific evi­ dence, the metabolite accumulation theory is still often used as an explanation for doms by m a n y coaches. this theory erroneously relates doms to the increased blood and muscle lactate levels that occur during high intensity exercise. however, neither muscle nor blood lactate concentrations remain elevated for more than 15-30 minutes post-exercise and return to pre-exercise concentrations within 60 minutes (oyono-enguelle et al, 1989). furthermore, doms is more severe after ec­ centric exercise, even though there is less blood lactate accumulation with this type of exercise. in addition, se­ vere doms may occur after stretching a muscle, despite the feet that blood lactate levels do not increase. a final address for correspondence mike lambert, phd , mrc/c1ct bioenergetics o f exercise research unit, department o f physiology, uc t medical school, observatory 7925 point is that mcardle's patients, who lack the enzyme glycogen phosphorylase and are therefore unable to break down glycogen to lactate during exercise, do not show an increase in blood lactate concentrations while exercising, and yet may still experience severe domb. (2) tissue damage th eory for d o m s h a m c the more scientifically plausible theory is that doms is caused by tissue damage. the following observations support o f this theory: (a) muscles with doms have microscopically identifiable disruptions o f myofibrils and streaming o f the z-lines, a common non­ specific finding in many muscular diseases (friden, 1984). (b) doms causes an increased leakage into the blood o f intramuscular enzymes such as creatine kinase (ck) and lactate dehydroge­ nase, (ldh) (clarkson et al, 1992). (c) doms is associated with the excretion of high concentrations o f 3-methylhistidine in the urine which is a non-metabolizable am i­ no acid found in the actin protein of the mus cle thin filaments (d) after exercise causing doms there are high concentrations of c-reactive protein in the blood which indicate tissue dam age (stra chan et al, 1984), and (e) following a marathon race, runner’s leg mus­ cles have intraand extra cellular oedema with endothelial injury, and dilation and dis­ ruption o f the t-tubules. there is also focal disruption o f the mitochondria (warhol et al 1985). in a rat experiment armstrong et al (1983) showed that monocytes, macro phages, satellite cells and fibroblasts were present in the muscle 1 to 2 days after se­ vere exercise which also suggest severe mus­ cle damage. furthermore, warhol et al (1985) showed that 12 weeks after a marathon, many muscle fibres had central nuclei and satellite cells indicating that the previously damaged fibres had reg enerated why does eccentric exercise cause doms? the contrast between eccentric and concentric muscle contractions in terms o f causing doms was shown clearly by asmussen (1956) in an experiment in which subjects raised a weight with one arm, and lowered it with the other. the subjects claimed that raising the weight (concentric contraction) often exhausted the muscle, whereas lowering the weight (eccentric contrac­ tion) felt easier. nevertheless, the muscles involved in the eccentric contractions were more painful several days later. this can be explained because eccentric mus18 sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) doms cle contractions lowering a load have less electrom yo­ graphic activity (emg) compared to concentric contrac­ tions raising the same load (newham et al, 1983). a lower emg activity indicates that less fibres are recruit­ ed to move the same weight and so during eccentric contractions each fibre undergoes more strain and hence is more prone to mechanical disruption (lieber and friden, 1988). muscle damage and pain during doms mechanical disruption o f the muscle fibre affects the structural and functional proteins and the connective tissue network (lieber and friden, 1988), causing a de­ crease in maximal force production (clarkson and tremblay, 1988) which may remain impaired for 3 weeks (newham et al, 1987). within a few hours there is a significant elevation in circulating neutrophils (smith et al, 1989) which infiltrate the site o f injury (kuipers et al, 1983). the pain in the muscles at this stage is possibly due to a disruption o f the connective tissue and to the dam age in the muscle itself (jones et al, 1987). v during exercise which causes doms it appears that the weak or more susceptible fibres are damaged to a greater extent (newham et al, 1987). if the damaged fibres are not repaired within a day the entire fibre or a segment o f the fibre degenerates as macrophages in­ filtrate and remove the cellular debris. at this stage there is an increase in serum prostaglandin e2 (pge ) concentrations (bansil et al, 1985; smith, 1991). pge2 decreases the threshold o f the pain receptors in the muscle (smith, 1991). the delayed muscular pain may in part be due to inflammation that occurs several hours after the activity (smith, 1991). during this period the size o f the damaged muscle may increase by 5-10% (jones and round, 1990). most o f this swelling can be attributed to oedema. this produces a significant in­ crease in intramuscular pressure at rest (newham and jones, 1985). small movements or palpitations may fur­ ther increase the intramuscular pressure, which pro­ vides a stimulus for the pain receptors already sensi­ tized by the pge2. this pain, however, is not reduced by anti-inflammatory drugs (donnelly et al, 1988; jones and round, 1990). the potential benefits of the delayed pain are not clear. whereas it can be argued that acute pain has a protective role by preventing further muscle contractions that may cause damage, doms does not rail into this category because o f its delayed response. physiological consequences of doms (a ) a ccum ulation o f calcium in the sarcoplasm one to two days after exercise causing muscle damage, the affected muscles shorten, and remain shortened for about 5 days (jones et al, 1987; cleak and eston, 1992) this excessive contraction at rest is thought to occur as a result o f an influx o f ca++ into the sarcoplasm either through the c a++ channels or through physical disruption o f the cell membrane (cullen and fulthorpe, 1975). it is also possible that the damaged connective tissue network is involved in causing the muscle to shorten (jones et al, 1987). the stiffness and shorten­ ing develop before the delayed pain which suggests that they are not causally related. continuously higher than normal resting levels of ca++ in the sarcoplasm are sequestered by the mito­ chondria. ca++ uptake into mitochondria occurs at the expense o f atp production and in extreme cases com­ promises the extent to which cytoplasmic ca++ con­ centrations can be controlled. uncontrolled rises in cyto­ plasmic ca++ concentrations activate a c a^ -d ep en ­ dent proteolytic enzyme which preferentially degrades z-discs, troponin and tropomyosin. a c a++-activated phosphoiipase also destroys cell and other membranes (jones and round, 1990). it is not known whether phos pholipase activity promotes ck release or whether the release o f ck occurs earlier as a result o f the mechani­ cal damage. (b ) elevated plasm a c k activity the mechanism causing increased plasma ck activity is not entirely understood. it appears to be exercise de­ pendent since downhill running causes plasma ck ac­ tivity to increase 3-6 hours after the bout, peaking 18-24 hours later, whereas local eccentric exercise causes plas­ ma ck activity to increase after 48 hours and to peak at about 7 days post-exercise (clarkson and tremblay, 1988). the delayed appearance o f ck activity in the plasma is thought to be due to the slow increase in membrane permeability (newham et al, 1987). it has also been suggested that the delayed ck response might also be due to the diffusion and mixing within the lymphatic system that clears the ck from the ex­ tracellular space (jones and round, 1990). because there is large variability in plasma ck ac­ tivity increases following exercise, which is not depen­ dent on age, fitness or degree o f soreness (noakes 1987), elevated blood ck activity cannot be used as a clinical test to quantify the degree o f muscle damage, el vouaren s moo ~ " ^fimple^begimen ^ fo p h e n o c sodium 1 0 0 mg m/3̂ (30[oxo] l/m sa journal of sports medicine september 1994 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) doms especially as the tim e course o f the elevation o f plas­ m a c k a ctivity is dissociated from both p a in a n d m us­ cle function im pairm ent (n ew ham et al, 1987). training response to doms t h e m uscles m ay adapt to d o m s for several w eeks a f­ ter a single bout o f eccentric exercise. this is suggested by the lower plasm a c k activity in response to a subse­ quent exercise bout, even though the pain rating is simi­ lar. th ere are 3 possibilities to explain this p h en om e­ non (n ew h am et al, 1987); (1) there is a change in m o to r unit recruitment pattern, (2 ) there is s o m e intrinsic adaptation in the mus­ cle fibre, or (3 ) fibres nearing the end o f their growth, o r a sm all part o f a weakened fibre are destroyed at the first exposure. a t this stage it seem s that the latter 2 points are the m ore likely explanations because the emg pattern does not ch an ge with training, su ggestin g that m uscle re­ cruitm ent is unaltered. th ere is also evid ence f° r con­ nective tissue involvem ent in the adaptation to doms. o ne possible explanation may b e that the first exposure to unfamiliar exercise causes m ain ly m uscle tissue dis­ ruption, but that as the m uscle becom es trained the d o m s is attributed m o re to connective tissue disrup­ tion. treatment for doms presently the treatm ent for d o m s can on ly b e pre­ scribed based on em pirical observations. th ere is d e ­ bate whether to rest com pletely until the pain subsides o r w hether to continue exercising, albeit at a low in­ tensity. sherm an et al (1984) did not find a difference in the recovery rate after a m arathon betw een a group o f runners w ho rested com pared to a grou p w ho con­ tinued to train. also, since both m od es o f treatm ent are co m m o n ly practised b y sports participants, it can be assum ed that neither m eth od is overtly superior to the other. a lthou gh static stretching exercises have been pro­ posed as a m o d e o f treatm ent for doms, (d e vries, 1966) this theory has not been tested adequately. in­ tuitively it appears that if the m uscles are d a m a g ed in the acute phase o f doms, then stretching the m uscle m ay be counter-productive. summary exercise, particularly exercise involving eccentric mus­ cle contractions, causes delayed m uscle pain with peak soreness occurring about 24 hours after the activity an continuing for up to a week. m uscle contractile func­ tion m ay b e im paired for several w eeks after the dam age. t h ere is m uch evidence to show that m uscle fibres with delayed-onset-muscle-soreness are damaged. these fibres do, however, repair and b ecom e m ore resis­ tant to d a m a g e in subsequent bouts o f exercise. a l ­ though elevated plasm a creatine kinase activity is as­ sociated with m uscle dam age, it cannot b e used to quantitatively assess the amount o f muscle dam age due to a large intra-subject variation and the variation due to the type of exercise activity. a nti-inflan^atoiy m edi­ cation d oes not reduce the severity ot doms. t h ere is no difference in recovery tim e when subjects have c o m ­ p lete rest com pared to when they exercise m oderately. references armstrong rb, r w ogiluie and j a schwane. ew rcbeinduced injury to rat skeletal muscle. j appl physiol. 54. 80-91, asmussen e. observations on experimental muscle soreness. acta rheum. scand. 2: 109-116, 1956. bansil ck, g c wilson and m h stone. role o f prostaglandins e a n d f2 alpha in exercise-induced delayed muscle soreness. med sa sports and exerc. 17:276, 1985. clarkson p m and 1 tremblay. rapid adaptation to exercise-induced muscle damage. j appl physiol. 65: 1-6, 1988. clarkson pm, k nosaka and b braun. muscle function after exercise induced muscle damage and rapid adaptation. m ed sci sports and exerc. 24: 512-520, 1992. cleak m j and r g easton. muscle soreness, swelling, stiffness and strength loss after intense eccentric exercise. br j sports med. 26: 267-272, 1992. n t cullen m j and jj fulthorpe. stages in fibre breakdown in duchenne muscular dystrophy. j neurol sci. 24: 179-200, ^ 7 5 . de vries ha. quantitative electromyographic investigation o f the muscte spasm theory o f muscle pain. a m j phys med 45:119-134 1966. donnelly ae, k mccormick, rj maughan, ph whiting and p m clark­ son. effects of a non-steroidal anti-inflammatory drug on delayed onset muscle soreness and indices o f damage. brit j sports med 22: 35-38, 1988. . . . , . . . friden j. muscle soreness after exercise: implications o f morphologi­ cal changes. int j sports med. 5: 57-66, 1984. jones da, d j newham, j m round and sej tolfree. experimental human muscle damage: morphological changes in relation to other indices of damage. j physiol. 375: 435-448, 1986. jones da, d j newham and p m clarkson. skeletal muscle stiffness and pain following eccentric exercise o f the elbow flexors. pain. 30, 233-242, 1987. jones d a and j m round. skeletal muscle in health and disease. man­ chester uniuersity press, 1990. kuipers h, j drnkker, p m frederik, p geurten and g v kranenburg. muscle degeneration after exercise in rats. int j sports med. 4: 45-51, 1983. , , lieber rl and j friden. selective damage o f fast g ly c o ly tic muscle fibres with eccentric contraction o f the rabbit tibialis anterior. acta physiol scand. 133: 587-588, 1988. newham dj, d a jones and rht edwards. large delayed plasma crea­ tine kinase changes after stepping exercise. muscle nerve. 6: 380-385, 1983. . newham d j and d a jones. intra-muscular pressure m the painful hu­ man biceps. clin sci. 69: 27p, 1985. newham cj, d a jones and p m clarkson. repeated high force ec­ centric exercise: effects on muscle pain and damage. j appl physiol 63: 1381-1386, 1987. noakes td. effects of exercise on serum enzyme activities in humans. sports med. 4: 245-267, 1987. . u c j oyono-enguelie s, m gartner, j marbach, a heitz, c ott and h freund comparison o f arterial and venous blood lactate kinetics after short exercise. int j sports med. 10: 16-24, j989 . sherman wm, l e armstrong, tm murray, f c hagcrman, dl costiu, r c stamn, jl ivy. effect of a 42.2km footrace and subsequent rest or exercise on muscular strength and work capacity. j appl physiol 57: 1668-1673, 1984. smith ll. acute inflammation: the underlying mechanism in delayed onset muscle soreness? m ed sci sports exerc. 23: 542-551, 1991. smith ll, m mccammon, s smith, m chamness and k obnen. white blood cell response to uphill walking and downhillpgging at similar metabolic loads. eur j appl physiol 58: 833-837, 1989. stmchan af, td noakes, g kotzenberg, a e nel, f c de b eer.c reac­ tive protein concentrations during long-distance running. bnt med j 289: 1249-1251, 1984. warhol mj, a j siegel, wj evans and lm silverman. skeletal injury and repair in marathon runners after competition. a m j path 118: 331-339, 1985. u sa journal of sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) advances in sports equipment technology that enhance performance chester r kyle ph d introduction m odern equipm ent has revolutionized m any sports, leading to m ajor im provem ents in performance, radical changes in technique, an increase in the sport’s popu­ larity o r safety, o r in so m e cases a com p lete ch ange in the structure o f the sport. it is the purpose o f this presentation to show the im portance o f equipm ent technology in m odern o lym pic sports and the com peti­ tive advantage that can b e gain ed by equ ipm ent im ­ provement. w henever there is an athletic com petition, there is an automatic conflict between those w ho m ake the con­ test rules and those w ho try to interpret the rules to their own advantage. in sports that use high tech n olo­ gy, it is even m ore com plex. t h e rule makers would like to ensure a fair contest betw een athletes and not have their sport d egen erate into a co m petition to see who can design the best equipm ent. on the oth er hand, manufacturers and designers will try to find ways o f stretching o r interpreting the rules so that equipm ent im provem ents m ight g iv e their athletes an “ unfair” ad­ vantage. for this reason, athletic governin g b od ies fre­ quently rule against equipm ent im provem ent and in ef­ fect freeze the sport in a tim e capsule. a n exam ple is the racing bicycle which rem ained basically un­ changed for about 100 years, (it has undergone rapid change recently). obviously, a certain am ount o f standardization in equ ipm ent is necessary. l o g ica lly a contest should be between athletes and not between equipm ent designers however, m any tim es there are g o o d reasons for allow ­ in g eq u ip m e n t innovation. changes will often im prove athletic performance and m ake a com petition safer bet­ ter equipm ent can g iv e the athlete a lo n g er co m p e ti­ tive life. for exam ple m odern m aterials in running shoes absorb shock and help prevent injury. in co m b i­ nation with resilient track and field surfaces there is no doubt that they also im prove perform ance. n the united states sporting go od s manufacture and sale is a 3 0 billion dollar per year business th ere is a great deal o f com petition a m o n g manufacturers to ave winning athletes use their equ ipm ent and there ,s a 9 reat deal o f pressure upon the sports rules c o m ­ m ittees by the equ ipm en t manufacturers to perm it in­ novation in order to stim ulate sales o f new equipm ent m the huge sporting g o o d s market. th ere is also pres­ sure from the athletes and coaches to perm it use o f the est equ ipm ent available. th ese forces have m uch the sam e effect as lobbying in governm ent. w ith pressure adjunct professor o f mechanical engineering ^m om ia state universitu, long beach 953 9 yy. old stage rd. weed, c a 96094 usa o f this sort on rules c o m m itte e s there will always be s o m e d e g re e o f continual change in sports equipm ent this cycle o f ch an ge creates p roblem s o f m ajor p ro­ portions. a new p iece o f equ ipm en t previously unde­ fined within the rules gives an athlete an obvious ad­ vantage. t h e sport’s rules co m m ittee passes a regula­ tion to control the new innovation. designers find a looph ole in the new regulations and design equipm ent to evade the rule which leads to new revisions and rules this adversarial ballet continues o n and on. it can be a distinct disadvantage to a country that d o es not have the tech n o lo gy to produce its own sports equipm ent. such countries must rely upon the open m arket which m ay b e several generation s behind. however, in general, designing equipm ent to the very lim it and even beyond the rules has a healthy, stimulat­ ing and beneficial effect on s p o rts w ithout such ac­ tivity, for example, skis would still be m ade o f wood with leather straps and the pleasure o f skiing with confidence and skill w ould be d en ied to m illions o f skiers high tech sports a 1984 report o f the cisoc s ports equipm ent and t ech n olo gy c om m ittee classifies the o ly m p ic sports as either high, m edium or low technology. s e e table in each o f the high tech sports the o u tcom e o f the event dep end s heavily upon the type o f equipm ent used. e quipm ent design changes can often result in m ajor im provem ents in athletic perform ance. a n aver­ a g e athlete could conceivably defeat a world class per­ form er by using illegal equ ipm ent for instance, in arch­ ery, m o d em com pound bows and lon g radius sights are forbidden since they would radically im prove scores com pared to the m o re traditional b o w s if equipm ent designers are see k in g to g e t m easurable results they would d o well to concentrate on the high tech sports m edium tech sports, dep end som ewhat on equipment, however athletic skill for outweighs equipm ent technol­ ogy. in low tech sports, any equ ipm ent is so standar­ dized that it has alm ost no influence on the outcom e o f the event. track and field is a sport that spans all three c a teg o rie s equipment changes that have revolutionized sports: track and field the bole vault until the 1950’s, p ole vaulters used b a m b oo p oles and vaulted into a sawdust pit and th e runways were o f cinders or dirt. m odern pits are now m ade o f d eep ab sorbant foam and the runways are o f a shock absorbant synthetic material that gives better traction. it would be inconceivable for a m odern vaulter to ju m p as high as 6 m etres and land in a sawdust pit without injury. th e sa journal o f sports medicine september 1994 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports equipment ta b l e 1 o lym p ic s p o rts where equipm ent tech n o lo gy influences perform ance high ar c h e r y b iath lo n b o b sle d d in g tech c a n o e in g / kayaking cycling lu g e m o d e r n pe n ta th lo n r o w i n g s h o o t i n g skiing yachting medium fe n c in g field h o c k e y ice h o c k e y tech figure sk atin g r o ller sk a tin g s p e e d s k a tin g t e n n is low b a s e b a l l b a s k e t b a l l boxing tech diving equest1an g ym n a st ic s ju d o f o o t b a l l s o f t b a l l sw im m in g synchro. swimming t a b l e t e n n is t e a m h a n d b a l l v o l l e y b a l l w ater po l e w e ig h tliftin g w restlin g h ig h , m e d iu m a n d tr a c k a n d field lo w t e c h , c o m b in e d m ost spectacular im provem ent, however, has been in the poles. using a b am b oo pole, cornelius warmerdam held the record for nearly 18 years at 4.72 meters, from 1942 to 1961. a slight im provem ent cam e with the in­ troduction o f steel and alum inium poles in the 1950’s although they did not im prove the record significantly. in the early 1950’s, herb jencks, a manufacturer o f fiberglass fishing p o les in southern california m ade a new m o d el d eep sea tuna p ole for com m ercial fisher­ men. t h e p o le was about 3 m eters long and 3 cm in diameter. jen ck’s son was a 45 kilo junior high-school polevaulter. a s a lark, he and s o m e o f his friends took one o f the fishing poles, used w ooden plugs for pole tips and tried polevaulting with the tuna pole. they prom ptly bettered their best heigh t by several inches com pared to the b a m b o o or steel poles they had been using. jencks began building poles for local high school vaulters and later for all com ers as they b ecam e m ore popular. figu re 1 shows what happened to the pole vault record after introduction o f the fiberglass pole. the record went from 4.7 m eters to over 5.2 m eters in just four years, from 1961 to 1965, after rem aining stagnant for the previous 18 years at present the record is about 6.1 meters. th e reason com posite poles are superior is that ener­ g y m ay b e stored in the p ole when it flexes, allowing the vaulter to hit the vault box m uch faster w ithout un­ due shock.2 th e p o le bends to o n e side, so that the vaulter m ay swing straight through. a t the top o f the swing, the stored en ergy in the p o le is returned, cata­ pulting the vaulter over the ban poles are wrapped so that they have a soft side and will bend preferentially in one direction — this side is m arked on each pole. m odern p o les are m ade o f carbon and glass laminate. the pole used by the present world record holder serge bubka w eighs only 2.6 kg and is 5.25 m eters long (about .75m shorter than his record height)! poles are specifically design ed for the w eight and skill o f the vaulter. bubka’s p o le is manufactured by gill sports o f (jrbana, illinois. probably the m ost fam ous incident involving a co m ­ posite p o le was when us vaulter bob s eagren had his carbon p o le outlawed at the last m inute by officials at the 1972 o ly m p ic s t h ey ruled that the p o le had not figure 1 w o r ld p o l e vault rec o rd s 1900-1984. sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports eqcjipmeni 1 s t 2 a ^ ? : comp ° s* e poles bend and store energy on the upswing, and release t h s e n e z z %theu1̂ £ % v op' fcu*w/»fe<2 g hhu f 5 spc«fc utf/iouf undue shock. the pole bends to the side to let the vaulter s z s j t ? ce " * h n t u c o t f z n s fibreglass and carbon poles in 1961, the pole vault record has increased over 1.5 metres. figure sa j o (jrnal o f sports medicine september 1994 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports equipment been on the m arket for sufficient tim e to perm it every­ on e to have the chance to purchase one. he was forced to vault with a borrowed p o le and won the silver m edal although he was the w orld record holder. a t present a vaulter m ay use any p o le design as lo n g as it is co m ­ m ercially available at least six m onths b efore the o ly m ­ pic g a m e s o n e unforeseen side-effect o f high tech n o logy in the polevault is that p o les are so expensive (about $300 $450 cis) that their cost elim inates m any o f the deve­ lopin g countries from co m p etin g in the event. a dent or mar in the surface can cause a p o le to shatter. e x­ trem e care must be taken to protect the p ole or a go od vaulter can g o through several poles in a season. t h e introduction o f the foam pit is often overlooked when considering p o le vault and high jum p records. th is m ade it safe for ju m pers to fall from great heights safely even if they landed incorrectly. a ls o runway sur­ faces have been specially design ed to giv e the right spring and traction to match the stride frequency o f the ju m p ers m odern shoes give better traction and resili­ ence. t h e com bination is a very high-tech system which perm itted the vault record to increase m ore in 30 years than it had in the previous 65 years since the b eg in ­ ning o f the sport. t h e high ju m p record also increased 15% in the sam e tim e period. part o f this was no doubt due to changes in technique and training, but the m ajor im ­ provem ent was due to equipm ent technology. a sid e from im provem ents in shoes and the take o ff surface, the fosbury flop would be im possible without the foam pit. jum pers could only land a few tim es in sawdust without spending the rest o f their life in a w heel chair. the javelin, discus and hammer like the p o le vault, the javelin record didn’t change m uch during the 1930’s and 1940’s. in the late 4 0 ’s, a stanford javelin thrower, bud held, was discouraged at the high cost o f h ollow w ooden swedish ja velin s t h e w ooden javelins o f the tim e were very fragile and bad luck m ight cause several to break in a week. t h ey were also hard or im possible to repair. he asked his brother dick held, an electrical engineer and contractor, to build a javelin for him that wouldn’t break. dick m ad e one o f aluminium that was an im m ediate success using the new javelins, bud w on the n c a a cham pionship three tim es and the a a u m e et several tim e s w hen he im ­ proved his distance by about 7 meters, the held javelin attracted international attention. w ithin a few months, d ick held was designing and building javelins full-time. he is still in business at o re go n track equipm ent, eu­ gene, o re g o n and has design ed the javelins that have set m ost o f the recent w orld record s t h e brilliant innovation introduced by held cam e when he realized that with javelin flight as with any other flight, aerodynam ics was critical. he built his jave­ lins to take advantage o f aerodynam ic lift like a w ing and he stream lined their shape so that they w ere far m o re efficient. unlike conventional javelins, the held javelin barely landed point down if thrown properly. it kept a positive angle o f attack during its flig h t if thrown in a vacuum for m axim u m distance, a m odern javelin would not travel as far, about 18% less than in air. t h e held javelins were term ed “ unstable” since they did not align them selves with the flight path like an arrow, but continually changed their angle o f attack during flight. by 1986, the javelin w orld record was 104,8 meters, a distance so far that javelins w ere som etim es landing on the track, an obvious danger to the com petitors s ee figure 3. a new javelin design was m andated by the governing b o d y that ch anged the center o f gravity and shape o f the javelin so that it w ould not have as much aerodynam ic lift. t h e w orld record im m ediately fell to 84.7 m eters — it has since risen to 90.98 meters, about 15 m eters short o f the old record. a m o n g other things, the regulations sp ecify the dim ensions and w eight dis­ tribution o f the new javelin and that they must be m ade o f a sin gle material. javelins have been ruled illegal several tim es in the past three years for violatin g these ru les o n e recent w orld record was voided because it was determ ined the com petitor had used an aluminium javelin stiffened with com p osite m aterials which changed the launch and flight characteristics o n e recent d evelop m en t in javelin tech n o lo gy is the work o f m ont hubbard o f the university o f california 3h3'loin\ . joh.bom (900 i9io 1920 1930 1940 19s0 l%0 1970 1900 1900 figure 3 javelin: olym pic w in n in g d istan c es a n d w o r ld records. 24 sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports equipment at davis.345 using an interactive com puter and a high speed d igitized v id e o cam era (200 fram es per second), hubbard has built a device that will measure the launch characteristics o f the javelin including velocity, launch angle, angle o f attack and angular velocity. using co m ­ puter simulation, hubbard has been able to successfully predict the optim um launch conditions that will pro­ duce m axim um distance. t h e javelin thrower is a ble to instantaneously com pare his actual throw with the ideal throw and to correct technique to achieve lon ger dis­ tances w orld class javelin throwers can launch the jave­ lin at about 30 meters per second. hubbard, using wind tunnel data, has shown that at this velocity, the old held javelin should be thrown with a 5.9 d eg ree initial angle o f attack, a launch a n gle o f about 30 degrees and a slight n egative pitching angular rotation o f 9.2 d egrees per second. t h e m axim um distance is very sensitive to errors in pitch angular velocity (twist). if an error o f a few d eg ree s per second is m ade, the javelin could fall 20 m eters short even when thrown with the sam e ve ­ locity. in other words, the “ lucky” throw was a real fac tor with the o ld javelin. a n analysis o f form er w orld re cord holder tom petranoff showed that his record launch conditions with the old javelin alm ost identical ly m atched hubbard’s predictions. for the new javelin, the release conditions are quite different.6 a lthou gh the launch an gle is the sam e at 30 degrees, the ideal pitch rotation is nose upward at three d egrees per second w hile the angle o f attack is a n egative two d e g r e e s t h e new javelin is much less sensitive, so the lucky throw is not such a factor in elite com petition. probably the next m ajor im provem ent in the javelin will be to increase its stiffness. vibrations decrease the efficien cy o f the throw. this brings up a point that when new equipm ent and techniques are introduced, careful analysis by biomech anicists and scientists can help im prove perform ance still further. c lose ties betw een athletes, coaches, train­ ers and sports scientists has b ec om e essential for suc­ cess. like the javelin, the discus also has the potential of flying much further in air than in a vacuum due to its airfoil shape (about 11% further). w hen the wind blows from the right direction, the discus throwers are ecstatic since a proper wind lifts the discus and carries it further. t h e stronger the wind the better. contrary to logic, it is a quartering head wind that is best; it corrects the ten­ dency o f the discus to tip over and follow a curved path. figure 4 shows the progress o f discus o lym p ic records unlike the p o le vault and javelin, the shape o f the dis­ cus has been fixed rigidly for a lo n g tim e and distance im provem ents have m ostly been due to better tech ­ nique and training. this is shown by the uniform rise in the distance versus tim e curve in figure 4. one major change has been m ade recently; the discus weight has been concentrated alm ost entirely in the rim, m aking the discus m o re stable in flight and easier to throw at higher v e lo c itie s t h e b o d y is m a d e o f kevlar or sheet aluminium, which w eighs very little as com pared to the rim. this high-tech discus is expensive and is only used in com petition since it can be easily dam aged. even with the hammer, aerodynam ics can play a part. in the early 1980’s the east g erm ans manufactured a hollow bron ze h am m er ball filled with mercury. since the ball had a sm aller diameter, it had less air resistance and flew further. t h e rules co m m ittee solved this pro­ blem by specifyin g a m inim um diam eter for the ball, thus m akin g the m aterial irrelevant. fast running tracks, tuned tracks and sh oes igor garrow, a us inventor, has recently obtained a pa­ tent on a tuned running shoe that he claim s will con ­ serve 7 0 % o f the im pact energy now lost when the foot contacts the ground. t h e shoe utilizes light efficient car­ bon springs in the heel and sole to absorb the shock o f im pact and later returns the en ergy when the foot leaves the ground. in theory this should work, however the spring would have to be tuned to the stride frequen­ cy, w eigh t and running technique o f each athlete to be effective without altering the runner’s m otion patterns figure 4 discus: olym pic w in n in g d istan c es 1900-1990. sa journal of sports medicine september 1994 25 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports equipment and hindering perform ance. in 1977, a group o f harvard scientists were asked to help design a new indoor track; in their studies, they predict that if the com pliance (springiness) o f the track were tuned to the runner, that running tim es should im ­ prove from 2 to 3 % when com pared to a hard track surface. in observations o f com parative running tim es on the harvard track and at other tracks, this was proven. o n e o f the last real frontiers to be explored in events involving running or jum ping, is to theoretical­ ly and experim en tally design the surface to suit the event (i.e. the long ju m p triple ju m p p o le vault, high ju m p and track running events). each event and dis­ tance would thus use a different surface, and even have variations in material at different locations (such as the long jum p take o ff area). this o f course would be tim e consum ing and expensive, however the results should be worth the effort. other sports rowing, canoeing, kayaking in 1982 the cis o ly m p ic c om m ittee created the elite a thlete program to im prove the chances o f cis athletes in the o lym p ic g am es by trying to develop better equipm ent, training techniques, coaching and support. o n e o f the outgrowths o f this program was the design o f new rowing shells, canoes and kayaks. ted van dus en, president o f the com posite engineering inc. o f con­ cord, massachusetts w h o is an o cean e n gin eer and a form er cis elite rower, has design ed and built a fleet o f carbon/kevlar boats for the us team s.9 using shapes derived from com puter m od els and re­ fined in tow tank tests, van dusen’s field experim ents and com petition results have proven the value o f his boats. us rowing, canoe and kayak teams have m edaled in both the 1988 and 1992 olympics. besides improved shape to lower wave and friction drag, van dusen has developed light weight com posite wing-shaped paddles and oars which are m ore efficient in producing propul­ sion. c om p osite oars and paddles, w eigh about half what traditional w ood en ones do. a n o ih e r o f van dus­ en’s innovations is the aerodynam ic rig ger for rowing shells. instead o f a conventional round tubing fram e­ work, the riggers are airfoil shaped, m aking them both lighter and stronger than conventional riggers. in addi­ tion they have a m uch lower air drag. although air drag is on ly 12 percent o f the total drag o f a rowing shell, races are often won b y fractions o f seconds and any im ­ provem ent could b e the w inning m argin. o n e interest­ ing sideligh t o f van dusen’s com puter studies showed that for m axim u m speed, the length and shape o f a boat should be m atched to the w eight o f the crew. van dusen has therefore built special boats for the w om en’s team s since their w eight is much less than a typical m en’s crew. simulators o n e rapidly grow in g field is the design o f sports sim u­ lators to give the athlete a chance for a realistic work out in a laboratory environment. with the advent o f fast computers, with crisp graphics displays, athletes are able to ga u ge their perform ance in real tim e and thus use bio-feedback to improve. several new devices have recently been built in the united states. a stationary paired oar rowing simula tor that displays force and power during a row ing cycle for both rowers, allows athletes, coaches and trainers to m ore accurately g a u ge training status and ability. a t the us o lym p ic training center, an instrumented swim flum e allows swim m ers to be vid eo taped in place for analysis o f their technique. a light nylon line fed from an instrumented reel, is attached to the swimm er and gives instantaneous velocity. pressure pads on the sw im m er’s palm s provide a m easure o f the thrust force per stroke. b iom echanical studies are under way that should identify efficien t sw im m ing m otions and allow swim m ers to refine their technique. a new table tennis robot has recently been dem on strated that can fire balls to any point on the table with variable velo cities up to 160 kph and with adjustable spin up to 6 000 rpm. it can be program m ed to simu late the serve and returns o f any player from average to an elite world cham pion. t h e inventor o f the robot. waquidi f alicoff o f the l o g ic handle o f ashland, o re gon, has im proved his standing in us table tennis by 200 places since he started training with the simulator it allows a player to practise against w orld class com petition at any time. probably the m ost spectacular o f the current simu lators is a project o f m ont hubbard o f the university o f california, davis. m ont and his students have ob tained the digital coordinates o f several o f the world cup and o lym p ic bobsled runs. t h e coordinates are used as input into a real tim e com puter m o d el o f bob sled dynam ics.10 using an actual bobsled, they have fitted hydraulic actuators that tilt the sled to sim ulate m otion, allow ing the driver to practise sled runs down the track of their ch oice without leavin g the laboratory. t h ey can follow any arbitrary path they choose. a silicon graph ics com puter and display m on itor allows the driver to steer using the standard bobsled steering linkage and pull handles. a t the finish, the com puter gives both the tim e and top speed o f the run and plots a red line along the course showing the path as well as a green line showing the fastest run. by repeating the program , the driver can com pare each trial with the fastest path and try different strategies to im prove the time. t h e colour com puter display is am azingly convincing, it includes shadowing, a horizon that tilts as the sled travels up and down the banks and realistic m otion as indicated by the texture and shadows speedin g by the sled. since actual ice tim e is very expensive, the bobsled sim ula­ tor allows the driver to b ec om e fam iliar with a course before actually m aking live runs. t h e ob ject o f any sim ulator is to reproduce reality accurately enough to m ake any training experience on the sim ulator as valuable as the real thing. in this age o f electronics it is a fertile field for developm ent. prob­ ably the easiest sport to sim ulate is cycling. a n e le c ­ tronically controlled ergo m eter can realistically sim u­ late any course in the world. a powerful fan is required to provide equivalent cooling for the rider. performance on a cycling ergom eter has been shown to correlate well 26 sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports equipment with actual road or track perform ance.11 athletic clothing well design ed athletic cloth in g can im prove perfor­ m ance in ways that are not always obvious. dr susan watkins a lon g with her textiles and apparels d epart­ m ent students at cornell university have designed an award winning protective uniform for fem ale hockey players.12 previously w om en were forced to wear uni­ form s m ade for m ale players, and the protection was dangerously inadequate since nothing fitted properly. d esigned specifically for the fem ale form, the new uni­ form is lighter, m ore flexible, the padding rem ains in place in com petition and the special protective padding is placed where needed. t h e lighter, well fitting, and m ore flex ib le clothin g allows the players to accelerate faster and to m ove with increased fluidity, therefore im ­ proving their gam e. t h e freed o m from bruises and in­ jury, assured by the efficien t padding, allows the ath­ letes to play with m ore confidence. t h e sam e approach taken by dr watkins could b e applied to field hockey or any oth er contact sport where protective cloth in g is used. light weight, flex ib ility and better protection should be the goals o f such a design program. in cycling, speed skating, skiing, the bobsled, the luge, and even in track and field, cloth in g is im portant for another reason — aerodynam ic drag. l o ose fitting clothing has a much higher wind resistance at the high speeds o f these sports. t igh t fitting, wrinkle-free suits that cover the entire b ody like a second skin have been used to substantially lower the wind resistance. w ind tunnel tests indicate that even in running, wind resis­ tance is significant, see table 2.1314 t h e tests in table 2 were perform ed on a manikin, fixed in a running pos­ ture.15 b y changing the clo th in g or hair fashion, large differences in wind resistance have been recorded. a m athem atical m o d el shows that even a 2 % reduction in wind resistance can have dramatic results on running perform ance, see table 3. t h e lead generated by a 2 % reduction in air drag varies from 0.1 m eters in the 100 m eter dash to 35 m eters in the marathon. in 1987, 1 designed a prototype skin suit for the us o lym p ic track team that included a h o o d 'to cover up the runners hair. this was worn by r oger k in gd om in winning the 1988 o lym p ic gold m edal in the 110 m eter t a b l e iii a dvantage in running due to a 2 % decrease in wind resistance distance lead t im e d ifference (m etres) (m eters) (s e c o n d s ) 100 0.1 0.01 200 0.3 0.03 400 0.9 0.10 800 1.3 0.17 1 500 2.0 0.29 5 000 5.8 0.90 10 000 9.2 1.55 marathon 35.4 6.44 (42 195 m ) kyle cr, athletic clothing, scientific american, march 1986, 254: 3: 104-110. hurdles. however in the 4 x 1 0 0 m relay, the second us team was allowed to race in the preliminaries and failed to qualify when on e o f the runners passed the baton over the line. t h e team com plained that the hood m uf­ fled the audible commands. however the relay team had not tried the suits b efore the o lym pics. th is under­ scores the importance o f thoroughly practising with any equipm ent you intend to use b efore com petition. b e ­ cause o f the bad experience, the h ood ed suits have not been used since, however, skin suits are now com m on in track and field. even in sw im m ing, clothing can lower drag. t h e us team has been experim en ting with slick full body suits for m ale swimmers. in theory they could have a lower drag than human skin. a n oth er im portant factor in clothin g is heat reflec­ tivity. larry bergland o f the cornell john b pierce foun­ dation has shown that reflective clothing im proves heat dissipation from an athlete exercising in direct sunshine, as com pared to bare skin.14 a t high noon, the b ody can absorb as much as 100 watts in radiant en ergy from the sun. this added heat load must b e carried away through sweating, thus adding to dehydration. reflec­ tive clothing can decrease this water loss, keep the body cooler and therefore lower the heart rate and increase endurance. th e best cloth in g b ergland tested had an aluminized reflective coating, but lighter colours proved to b e better than dark. bergland highly recom m ended that the n ew zealand all-blacks ch ange their colours. j o k in g aside, in hot clim ates, special heat reflective clothin g that efficien tly wicks m oisture away from the skin can definitely im prove perform ance in endurance events. cycling historically, european manufacturers have always pro­ vided bicycles for the us c ycling team s because euro­ pean racing equ ipm ent was superior. in 1984, for the first time, the us o lym p ic cycling team used their own cycling equ ipm ent with spectacular results. t h e last o lym p ic cyclin g m edal the us had won was a bronze in the road race in 1912. in 1984, they won nine, in­ cluding two g o ld medals. t a b l e ii clothin g wind tunnel tests t y p e o f c lo t h in g drag (g ) change in wind resistance ( % ) h air tests n o hair 1.50 0.0 l on g s m o oth hair 1.52 + 1.5% short curly hair 1.556 + 3 .9 % m edium wavy hair 1.56 + 4 .2 % clothing tests tight lycra track suit 1.50 0.0 m edium track suit 1.53 + 2.1 % large track suit 1.57 + 5 .1% tests at california institute of technology, c r kyle, 1986. sa journal of sports medicine september 1994 27 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports equipment starting in 1982, under the usoc elite athlete pro­ gram, at the request o f dr edmund burke, then tech­ nical director o f the (jscf, i organized a group o f 20 people to design and test cycling equipment the group included dr paul maccready, paul van valkenburgh, don guichard, dr allan a bbott jack lambie, jim gor­ don and bruce longson. we designed and built a com­ pletely integrated aerodynamic cycling system includ­ ing clothing, helmets, shoe covers, disk wheels, an aero tubing funny bike, aero shifters, disk sprockets, aero cranks, and clip on pedals the wheel size o f the bikes varied with the event in the team pursuit we used two 24 inch wheels so that the teams could draft closer for lower air drag. we performed hundreds o f full scale wind tunnel tests at texas a&m and cal tech that verified that our system had a much lower air drag than con­ ventional racing bicycles the cis olym pic bike frames were made by huffy based on our prototypes the other equipment was manufactured by our group our tests showed that the equipment was seconds to minutes faster in the olympic cycling events experience proved us right.1718 figure 5. wind tunnel testing o f bicycles lead to the de­ velopment o f the time trial funny bike in 1984. the photo shows the texas a& m wind tunnel, and the bicycle that was used to set the world am ateur hour record (john frey usa, 49.946 km; oct, 10, 1991). since 1984, every important time trial record in the world has been broken using variations o f the “funny bike” . in 1986 and 1987 don guichard and i built a monocoque carbon funny bike for the dupont compa­ ny which was intended for use by the cis team in the 1988 o lym pics it had the lowest air drag o f any bike we ever measured in the wind tunnel. however when ed burke took our plans to the technical commission o f the uci, they rejected the bike as illegal and immedi­ ately passed a set o f rules restricting tubing size and mandating a triangular frame. this assured that our du­ pont bike could not be used. we abandoned the project in 1991 the (jci unaccountably changed their racing regulations making monocoque composite bikes legal. mike burrows o f england along with lotus ltd, de­ signed and built a bike very similar to ours (but much improved) on which chris boardman set a new world record in the 4 000 meter pursuit, winning the event by several seconds burrows had been working on com­ posite monocoque bikes since 1982 and neatly took advantage o f the rule revision with brilliant results as i mentioned in the beginning o f this paper, rule changes continually occur, usually as a result o f political pres­ sure o f one sort or another. when changes do happen, it pays to rapidly take advantage o f them as burrows did. r e f e r e n c e s a dvan ces in s p orts equipm ent techn ology that enhance perform ance 1. sports equipment / technology, problems and programs. report o f the cis olympic committee sports equipment and technolo­ gy committee, december 5-7, 1984, colorado springs, colora­ do, (isa, p. 7. 2. hubbard m. “dynamics of the. pole vault". j. biomechanics, v13, no. 11, 1980, pp 965-976. 3. hubbard m and hj rust "javelin dynamics with measured lift, drag and pitching moment". asmej. applied mechanics.' v51, no. 2, pp 406-409, 1984. 4. hubbard m and hj rust “simulation of javelin flight using ex­ perimental aerodynamic data". j. biomechanics. ' v17, no. 10 pp 769-776, october 1984. 5. hubbard m. "optimum javelin trajectories". j. biomechanics.’ v17, no. 10 pp 777-787, october 1984. 6. hubbard m. "the flight of the javelin". in a special adversiting section, "the technology of winning", in scientific american fol­ lowing p. 60. scientific american, september 1988, p. t20-t21. 7. fmhlich c ''aerodynamic effects on discus flight". personal com­ munication with cliff frohlich, university of texas, marine science institute, galveston, texas. 8. mcmahon ta and pr greene. "fast running tracks". scientific american, v239, december 1978, pp 147-157. 9. van dusen es. "racing shells, canoes and kayaks". same ad­ vertising section as in ref. 6. scientific american, sept. 1988, p. 76-77. 10. hubbard m, m kalla y and p rowhanl ‘three dimensional bobsled turning dynamics". international journal of sport biomechan­ ics. v5, pp 222-237, 1989. 11. kyle cr and vj caiozzo. "experiments in human ergometry as applied to the design of human powered vehicles". international journal of sports biomechanics. v2, pp 6-19, 1986. 12. watkins s. “a protective uniform for female hockey players". a cornell university student team report, winner of the 1992 usoc sports equipment and technology committee student design contest presented at the setc quadrennial conference novem­ ber 20-23, 1992, colorado springs, colorado. 13. kyle cr and vj caiozzo. "the effect o f athletic clothing aero­ dynamics upon running speed'. medicine and science in sports and exercise. vl8, no. 5, 1986, pp509-515. 14. kyle cr. "athletic clothing". scientific american, v. 254, no. 3, pp 104-110, 1986. 15. kyle cr. "the wind resistance of racing bicycles, cyclists and athletic clothing. report to the usoc sports equipment and tech­ nology committee. march 10, 1987. 16. bergland l, "evaporative weight loss as a measure of absorbed radiation in the human". 8th conference of biometeorology and aerobiology, american meteorological society, boston ma, 1987. 17. kyle cr and er burke. "improving the racing bicycle". mechan­ ical engineering. vl09, no.6, pp 35-45, 1984. 18. kyle cr. “wind tunnel tests of aero bicycles". cycling science, v3 no. 3, sept/dec 1991, pp 57-61. • these papers are available through the author, mont hubbard, mechanical engineering department, university of california, davis, california 95616, tel. (916) 752-6450. 28 sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) readership survey if you wish to continue receiving this journal, free of charge, please fill in the form below and return it to: glenbarr publishers cc private bag x14 parklands 2121 nam e:............................................................................................................... address:................................................... c o d e:.............. speciality: s a j o u r n a l o f spo r ts m ed ic in e s e pte m b e r 1994 29 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) die effek van ’n stresweerbaarheidsprogram op valskermspringers dawie scheepers en justus potgieter summary a stress management programme for skydivers was de­ veloped from available literature. a n experimental group (n =1 8 ) and control group (n =18) were used to evaluate an eight-week programme. preand post-experimental psychological and physiological data proved the pro­ gramme to be effective according to a variety o f criteria. inleiding stres kan ’n beduidende invloed o p sportprestasie uit oefen en in ’n sportsoort soos valskerm spring kan dit een van die belangrikste sielkundige p rob le m e wees w aarm ee die d ee ln em er te doen kry. talle valskerm ­ springers m et g o e ie potensiaal tree v ro e g uit, dikwels om dat hulle nie geleer het o m stres te hanteer nie. daar is o o k valskerm springers wat as g e v o lg van stres nooit w erklik doeltreffend kan konsentreer o p hul spronge en form asies nie. fenz en jones (1972) se navorsing dui daarop dat stres wat in vaiskermspring ervaar word, n ie net opjos en verdwyn nie, m aar deur die springer beh eer m oet word. fenz (1973) haal en kele studies aan wat daarop dui dat d ie kwessie van streshantering in valskerm ­ spring vaag en indirek aangespreek word. verder wys brewer en shillinglaw (1992) daarop dat d ie literatuur wat handel o o r sportsielkundige dienste gew oonlik ver wys na intervensies o p ’n individuele basis en dat daar ’n b eh oefte is aan navorsing o o r die geskiktheid van sielkundige ondersteuning in groepsverband. d ie hui d ig e ondersoek het in hierdie b eh o efte p rob eer vol doen. die prim ere probleem wat hierdie ondersoek aan­ gespreek het, was d ie daarstelling en evaluering van 'n stresweerbaarheidsprogram spesifiek vir 'n groe p val­ skermspringers, maar wat o o k vir ander sportsoorte van nut kan wees. ’n belangrike faktor by die ontwerp van ’n sielkundige program is die praktiese toepasbaarheid daarvan op die teikengroep. d ie opsteller van so ’n program beh oort dus benewens sy sielkundige bevoegdheid o o k genoeg sam e praktiese ervaring in valskerm spring te he. die hoofnavorser het aan hierdie vereistes voldoen. streekproef ses-en-dertig aktiewe valskerm springers in die weste like provinsie en boland is by hierdie eksperim ent be trek. d ie ervaringsvlakke van die springers het gewisdepartement menslike bewegingskunde (jniversiteit van stellenbosch stellenbosch 7600 south africa sel van drie tot 1 720 spronge. hierdie g ro e p is in ’n eksperim en tele g roe p (n = 1 8 ) en ’n kon trolegroep (n = 18) verdeel. o m praktiese redes is die verdeling gedoen op die basis van klublidmaatskap. s leg s die eksperi­ m entele g ro e p het tussen die tw ee evaluasiesessies ’n stresweeerbaarheidsprogram gevolg. die stresweerbaarheidsprogram d ie intervensieprogram het oor ’n periode van agt weke gestrek en word kortliks bespreek. tydens d ie eerste sessie word p sig om etriese evalue­ ring gedoen. toetslin ge voltooi die ipat-angsskaal as o o k ’n biografiese vraelys. die sport competion anxiety test (s c a t ) (martens, 1977) ’n sportspesifieke meetin strument wat uit 15 stellings bestaan en trek-angs bin ne sportsituasies bepaal, is o o k voltooi. b eid e groep e is o pgelei om hul harttempo te monitor. toe hierdie stu die uitgevoer is was daar nie tegn ologiese middels, soos b yvoorb eeld polshorlosies, g ered elik beskikbaar om harttem po o p ’n gerieflik e en ek on om iese m anier te m on itor nie. harttem po is g e n ee m op die o g g e n d van hul sprang, tydens die opstygfase en wanneer die vlieg tuig sy h oo gste h o o g te bereik. in sessie twee tree die intervensieprogram in werking m et ’n bespreking van rasionele em otiewe terapie (ret) (ellis, 1974). d ie gron dslag van hierdie benadering is dat sielkundige p rob le m e grootlik s die g e v o lg is van irrasionele denke. d ie m ens kan h om self van baie on gelu k k igh eid bevry as hy leer o m irrasionele denke te elim in eer en logies en rasioneel te dink. d ie basis van hierdie sielkundige intervensie is dus o m die valskerm springer te leer o m rasioneel te dink. d ie ret-sessies is spesifiek van toepassing o p valskerm spring gem aak. in hierdie sessie m aak die springers o o k kennis m et progressiew e ontspanning. d ie tradisionele tegniek word effens gew ysig o m aan te pas by d ie beknopte ruimte binne die vliegtuig. aan d ie einde van d ie ses­ sie, aso ok na aflo op van elk van die daaropvolgende sessies, kry die springers tuiswerkopdragte. sessie drie word w eer eens in gelei m et ret. die in houd van d ie vo rig e sessie word hersien waarna die springers se tuiswerk o o r ret en progressiewe ontspan­ ning gekontroleer en bespreek word. irrasionele gedag tes wat a lgem een vo ork o m word bespreek. d ie sprin­ gers word daarop gew ys dat irrasionele opvattings wat em osion ele problem e veroorsaak deur vorige ervarings (kondisionering) m aar veral as g e v o lg van sosiale leer ontstaan. d ie belangrikste kategories waaronder hier­ die irrasionele ge d a gtes m anifesteer sluit onder ande re in absolutistiese denke, katastrofering, negatiewe self beoordeling, o n g eld ige gevolgtrekkings, swart/wit den­ ke, en “ek-kan-dit-nie-verdra-nie” denke. die sessie word, 30 sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) stres soos d ie v o rig e sessie, afgesluit m et ’n vo lle d ig e oefe ning van progressiewe ontspanning en ’n ret-tuiswerk opdrag asook ’n opdrag o m progressiewe ontspanning m et behulp van ’n geskrew e uiteensetting van die pro sedure daagliks tuis te oefen. sessie vier begin m et hersiening van v o rig e werk. daar word seker ge m a a k dat die springers d ie kriteria van rasionele opvattings ken en dat alm al ’n paar voor b eeld e m et betrekking tot die abc-analise van em o sies n eergeskryf het. d ie sessie word afgesluit m et pro­ gressiewe ontspanning, m aar sonder die spanningsfa se. d ie d o el van hierdie ontspanningsprosedure is om d ie springer m e er su ggereerbaar te m aak vir die daar op vo lgen d e beeldingsoefening. in sessie v y f word r e t bespreek waarna progressiewe ontspanning en outosu ggestie as ontspanningstegnie ke g e o e fe n word. sessie ses word m et re t b egin waarna progressiewe ontspanning, outosuggestie-ontspanning en beeldin g geoefen word. realistiese b eeldin g van die valskermsp ring in die bep aalde form asies wat g e d oe n gaan word, word geoefen. in hierdie stadium word springers gehelp o m in rasionele term e aan valskerm spring te dink son­ der o m byvoorbeeld te verabsoluteer o f te katastrofeer. dit is belangrik dat hulle hierdie prosedures so veel m oontlik oefen aangesien dit is hoe hulle sal m oet dink wanneer hulle spring. die springers word aanbeveel om o f progressiew e ontspanning, outosuggestie-ontspan ning o f ’n kom binasie van die tw ee tegnieke te gebruik wanneer die vliegtuig besig is o m tot o p hoogte te klim. d ie springer m o e t tydens hierdie fase kan ontspan ter wyl hy die sprang wat vo orle in detail beeld. sessie sewe word gew y aan ontspanning en beelding. daarna w ord die hele proses van rasionele denke her sien in die vorm van ’n lesing en ’n groepbespreking. tydens sessie agt word p sigom etriese evaluering ( scat en ipat) g e d o e n asook bep alin g van harttem ­ po. springers word o o k gevra o m d ie a fg e lo p e stres w eerbaarheidsprogram te evalueer. resultate in die voortoets is m et die uitsondering van d ie scat tellings g e e n verskille tussen die eksperim en tele en kontrolegroep gevind nie. o p grand van die feit dat daar wel een veranderlike was waar d ie twee groep e van mekaar verskil het, is daar in die statistiese verwerking van die data ’n on tledin g ge d o e n van d ie relatiewe verskille tussen die vooren na-toetse binne die twee groepe. die m ate waarin die veranderlikes binne een g ro e p toeof afgeneem het, is vergely k m et die h oeveelh eid veran dering wat binne d ie ander groe p plaasgevind het. d ie resultate (sien tabel 1) dui daarop dat beide die psigom etriese en fisio lo g iese veranderlikes by die e k ­ sperimentele groep ’n verbetering geto on het, terwyl die kon trolegroep se tellings konstant ge b ly o f sells ver sleg het. in die geval van die ipat-veranderlike (angs) het die kon­ trolegroep se telling toegen eem terwyl die eksperim en­ tele groe p se telling nie beduidend verander het nie. d ie toenam e in die angstelling van die kontrolegroep kan nie verklaar w ord nie, maar het m oon tlik te m ake m et n verh ogin g in stres in die alledaagse lewe van die toetslinge. d ie g e m id d e ld e scat-telling (kom petisie-angs) van die eksperim en tele g ro e p het ’n beduidende afnam e geto o n na a flo o p van d ie stresweerbaarheidsprogram . d ie kontrolegroep se telling, daarenteen, het redelik konstant gebly. wat d ie harttem po betref, het die eksperim entele groep beduidende afnam es g e to o n by al drie m etings (o g g e n d van sprang, opstygfase en wanneer die v lie g ­ tuig sy h oo gste punt bereik het). d ie kontrolegroep se gem id d eld e tellings het konstant gebly, m aar in die g e ­ val van die opstygfase het dit selfs verhoog. a s g e v o lg van ’n ge b rek aan narvorsingspubfikasies hieroor kon hierdie bevindinge o n gelu k k ig nie m et an der navorsingsresultate vergelyk w ord nie. subjektiewe evaluering deur proefpersone springers is gevra o f hulle steeds d eel van d ie program sou wou gew ees het as hulle v o ora f gew eet het wat die program behels. van die agtien proefperson e het elf aangedui dat hulle “ beslis” daaraan sou d ee lg en eem het, terwyl die res (7 ) aangedui het dat hulle wel aan die program sou d e e lg e n e e m het. verder het ses per sone aangedui dat die program “ beslis n od ig” was, ter­ wyl n ege persone van m ening was dit dit “ n o d ig ” was. drie persone was onseker. sewe toetslinge het aange­ dui dat hulle "gew eld ig baie” baat daarby gevind het, t a b e l 1 ’n v ergelyking van vooren n atoets-g em idd eldes eksperim entele q roep (n==18) k ontrolegroep (n = 18) v oortoets n atoets t v oortoets n atoets t ipat 31.28 27.39 1.84 26.67 30.89 6 . 3 1 * * * s c a t 22.28 19.78 3 .1 0 * * 18.44 18.50 0 . 0 8 h a r t t e m p o o g g e n d 79.33 76.44 2.8 2 * 80.39 82.00 1 .7 1 o pstyg 96.61 90.56 4 .6 4 * * * 93.00 95.33 2 . 1 7 * h o og 101.50 96.78 3 .1 9 ** 102.11 104.89 1 . 8 3 * p < .05 * * p < .001 * * * p < .0001 sa journal of sports medicine september 1994 31 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) stres tien persone “ redelik baie” en een persoon het “gemid deld” baat gevind. die respondente is versoek om aan te dui by watter aspekte van die program hulle die meeste baat gevind het. vyftien persone het aangedui dat die rasioneel emotiewe terapie vir hulle die nuttigste was twee per­ sone het progressiewe ontspanning as die waardevolste aspek beskou. a gt persone het outosuggestie as die swakste gedeelte van die program geevalueer terwyl se we persone beelding as die aspek beskou het waarby hulle die minste gebaat het. drie persone het aange­ dui dat die progressiewe ontspanning die minste nut gehad het. die lae waarde wat aan progressiewe ont spanning toegeken is, is verrassend aangesien hierdie tegniek in talle programme van hierdie aard buite die sportarena ingesluit word. hoewel die response van die toetslinge uiteraard sub jektief is en nie statistics bevestig kan word nie, is dit nogtans belangrik om na hul subjektiewe ervarings te kyk. die meeste proefpersone (10) wat die program g e ­ volg het, het aangedui dat hulle na afloop van die pro gram stres beter kon kanteer as voor die aanvang van die program. daarteenoor het die meeste toetslinge (11) in die kontrolegroep aangedui dat hulle dieselfde ma­ te van stres as tevore ervaar het. daar het dus nie ’n verbetering ingetree met betrekking tot hul subjektiewe vermoe om stres te hanteer nie. dit impliseer egter nie dat hierdie groep persone tekortkominge met betrek king tot streshantering gehad het nie. slot op grond van die die objektiewe data en subjektiewe beoordeling van die proefpersone kan daar aanvaar word dat hierdie stresweerbaarheidsprogram suksesvol was in terme van streshantering vir die groep valskerm­ springers. hoewel dit nie impliseer dat hul prestasies noodwendig verbeter het nie, onderstreep dit nogtans die nut van sportsielkundige ondersteuning by die voor bereiding van sportlui. v e r w y s in g s brewer bw & shiiiinglaw r (1992). evaluation of a psychological skills training workshop for male intercollegiate lacrosse players. the sport psychologist, 6, 139-147. ellis a (1976). humanistic psychotherapy. the rational-emotive ap­ proach. new york: mcgraw hill. fenz wd (1973). stress and its mastery: predicting from laboratory to real life. canadian journal of behavioral science, 5, 332-346. fenz wd & jones gb (1972). individual differences in physiological arousal and performance in sport parachutists. psychosomatic medicine, 34, 1-8. fenz wd & jones gb (1974). cardiac conditioning in reaction time task and heart rate control during real life stress. journal of psy­ chosomatic research, 18, 199-203. martens r (1977). sport competition anxiety test champaign il: hu­ man kinetics. rowel fm & vemerjp (1982). anxiety and performance relationships in first-time parachutists. journal of sport psychology, 4, 184-188. roginska w (1969). a psychological analysis of parachuting. prezegtad psychologiczy, 18. 33-50. cd voltaren gt: diclophenac sodium 5 0 mg 32 sa journal o f sports medicine september 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) case report 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license a “scattered” scat in a football goalkeeper: a case report s bosch,1,3,4,5 md, m med (sports med); pl viviers,1, 2, 3,4 mbchb, m med sc, msc (sports med), facsm; r de villiers,6 mbchb, mmed (rad. d); w derman,1,2,3 mbchb, bsc (med) (hon), phd, ffims, facsm 1 institute of sport and exercise medicine, division of orthopaedics, faculty of medicine and health sciences, stellenbosch university, south africa 2 ioc research centre, cape town, south africa 3 fifa medical centre of excellence, stellenbosch university, south africa 4 campus health service, stellenbosch university, south africa 5 catholic university of leuven, department of physical medicine and rehabilitation, leuven, belgium 6 winelands radiology, institute of orthopaedics and rheumatology, stellenbosch, south africa corresponding author: p l viviers (plviviers@sun.ac.za) case report a 20 year old male football goalkeeper sustained a traumatic head injury due to a collision with another player while reaching for the ball. upon impact, he was elbowed on the right mastoid and collapsed, but got up immediately after the incident. he felt disoriented and confused and was unable to prevent a goal from being scored seconds after the impact. he was subsequently removed from the field of play. there was no loss of consciousness at any time. during the sideline evaluation, he complained of dizziness, blurred vision and amnesia. the player was then referred to an accident and emergency department, closest to the field of play, for further evaluation by a physician. at the time of admission, symptoms of a painful and stiff neck had developed, as well as a feeling of pins and needles in the right hand, which was aggravated by movement. following a clinical examination, an x-ray of the cervical spine was performed, which showed no abnormalities. a further clinical examination revealed no other neurological signs or symptoms. the patient was admitted overnight for observation. the following day, he was discharged as no deterioration in the clinical picture was noted. he was prescribed pain medication (paracetamol) when necessary, provided with a soft collar and an information leaflet requesting him to seek medical attention if his symptoms deteriorated. five days after the initial trauma, the patient was evaluated by a physiotherapist and where he requested removal of the soft collar. however, clinical examination revealed a sensory loss at the c4-c5 dermatome of the right arm. the patient was then referred to a sports physician, who confirmed the findings of the physiotherapist. further examination using the sideline concussion assessment tool (scat) was performed. symptoms noted included headache, difficulty concentrating, drowsiness, difficulty getting to sleep, balance disturbance, feelings of irritablity, nervousness, slowed down movement and feelings of fogginess, and body numbness, which totalled a score of 10. subsequently, a neuropsychological (np) online examination (cogsport®) was performed, which resulted in a total score of 462 out of a possible 600, indicating an abnormality of neuropsychological functioning. due to the ongoing neurological symptoms in the right arm, a magnetic resonance imaging (mri) of the cervical spine was requested, which showed a mild chronic bulge of the disc on the right c6c7 level. unfortunately, the patient did not comply with the arranged follow-up visit and only presented again at the clinic on day seventeen after injury. at this visit, he presented with symptoms of headache, vomiting, dizziness, sleepiness and a sensitivity to light. a c4-c5 dermatome sensory loss was still present in the right arm. furthermore, weakness of handgrip strength and shoulder movement were also noted. there were still no clinical signs of raised intracranial pressure or structural intracranial pathology, specifically a fundoscopical examination was considered normal. the scat score was once again 10. a repeat online neuropsychological examination was conducted, which showed deterioration in test results (scoring 427 out of 600). the abnormal pattern of persisting symptoms raised suspicion for undiagnosed intracranial pathology, and therefore an immediate referral to a neurosurgeon was made. the neurosurgical evaluation revealed a distressed and uncomfortable patient, clutching his neck and occipital region, background: in an acute field-side setting, it is often challenging to differentiate benign sports-related concussion (src) from potential, more sinister, intracranial pathology. moreover, recovery in the ensuing days and weeks is often complex as the resolution of classical signs and symptoms does not always follow a standard pattern. aim: to highlight the value of a structured and repeated thorough clinical assessment approach toward src, particularly as atypical and unexpected sequences in patient recovery patterns may require further specialist referral and intervention. findings: a football goalkeeper sustained a concussion in which symptoms failed to resolve as expected. deterioration in his clinical condition led to an eventual diagnosis of chiari malformation (type i), which required surgical intervention. implications: non-typical recovery patterns of concussion may be indicative of increased severity when considered retrospectively. however, clinicians should not discount the possibility of underlying conditions. keywords: concussion, soccer, sports-related head injury s afr j sports med 2020; 32:1-3. doi: 10.17159/2078-516x/2020/v32i1a7737 mailto:plviviers@sun.ac.za https://orcid.org/0000-0002-6728-0663 https://orcid.org/0000-0001-6682-3438 https://orcid.org/0000-0001-6114-126x https://orcid.org/0000-0002-8879-177x http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7737 case report sajsm vol. 32 no. 1 2020 2 with some non-dermatomal sensory loss bilaterally in the upper limbs. an initial suspicion of transverse sinus thrombosis was raised. it should be noted that the patient’s family confirmed a long history of recurrent, severe headaches suffered by this patient as a minor. the mri of the brain (fig. 1) revealed low-lying cerebellar tonsils, with no hydrocephalus or syringomyelia. a diagnosis of a chiari malformation, type 1 (cm-i), was made. immediate decompression surgery was performed by means of an enlargement of the foramen magnum and partial c1 laminectomy, followed by duraplasty. after a period of physical and cognitive rehabilitation, the patient resumed activities of daily living and completed his academic studies at university the following year. furthermore, there was an uncomplicated course of events post-surgery. discussion in the acute setting, it can often be a challenge to differentiate src from potential life-threatening intracranial pathology, such as an intracranial haemorrhage or cerebellar herniation with compression of the tonsils due to a cm-i. the berlin consensus statement on concussion states that in a src “…the impairment of neurological function resolves spontaneously and completely”.[1] this case illustrates the importance of a structured and repeated clinical assessment (including a thorough history, clinical examination and special investigations) where the scat and np tests play an integral part in the monitoring of the athlete’s recovery and resolution of signs and symptoms over time. in this case, a deterioration of initial symptoms was noticed, as well as the onset of new symptoms, with an accompanying, unexpected deterioration of scat and np testing results. this deviation in the expected pattern of resolution of symptoms led to the suspicion of further pathology. eventually, a diagnosis of a cm-i, where classification is based on severity[2], was made and the patient was managed accordingly. the prevalence of a cm-i in the normal population varies from 0.2% to 3.6%.[3] in this condition, the pathophysiological mechanisms of altered cerebrospinal fluid flow create a negative downward pressure gradient across the craniocervical junction, and, if combined with raised intracranial pressure, the presenting clinical symptoms may vary and might be persistent.[4] although most people with the cm-i condition remain asymptomatic, acute symptoms may develop either spontaneously or after trauma.[5] in a study by yarbrough et al. which investigated the acute onset of neurological symptoms in children with cm-i, half of all cases described were following minor head trauma. one of these cases was a football player who developed a paresthesia of the arm after a blow to the head during a flag football game.[5] the safety of sports participation in patients with asymptomatic cm-i, especially in contact or collision sports, is still debated, considering the incidence of concussion in male football players is relatively low (1.08 concussions per 1000 athlete exposures, where one exposure is considered a single practice or game).[6] a study by meehan et al. describing 147 athletes with cm-i from different sporting codes who were followed over time, reported that not one sustained a catastrophic injury over the 3 year period.[7] similarly, a study by strahle et al., which evaluated 503 cm-i patients (of which 328 participated in sports) over a 46 month period, reported no serious or catastrophic neurological injuries in the entire cohort.[8] thus it appears that the condition is benign without the presence of an inciting event. although literature on this topic is limited, most authors suggest a case-by-case evaluation, with permission to take part in contact sports, following counselling from a neurosurgeon on the possible risks. conclusion this case report illustrates the importance of a structured clinical follow-up of concussion in sports. it is important for medical staff to recognise sequential patterns in developing symptoms which could indicate possible intracranial pathology. the use of the scat and importance of np testing in the sequential follow-ups raised suspicion of a complicated process of recovery from src in this particular case. whilst this patient presented with evolving symptomatology and eventually required surgical intervention, literature suggests that overall sports participation in patients with asymptomatic cm-i is a low risk for morbidity and mortality, even for contact and collision sports, including football. author contributions: sb: conception, design, analysis and interpretation of data, drafting for important intellectual content, approval for publication of this version. pv: conception, design and interpretation of data, critical revision for important intellectual content and approval for the version to be published. rdv: interpretation of data, critical revision of the radiology content and approval for the version to be published. wd: design, interpretation of data, critical revision for important intellectual content, and approval of the version to be published. references 1. mccrory p, meeuwisse w, dvořák j, et al. consensus fig. 1. mri of the brain (day 17) case report 3 sajsm vol. 32 no. 1 2020 statement on concussion in sport-the 5th international conference on concussion in sport held in berlin, october 2016. br j sports med 2017; 51(11):838-847. [http://dx.doi.org/10.1136/bjsports-2017-097699] [pmid: 28446457] 2. horn sr, shepard n, vasquez-montes d, et al. chiari malformation clusters describe differing presence of concurrent anomalies based on chiari type. j clin neurosci. 2018; 58:165171. [https://doi.org/10.1016/j.jocn.2018.06.045] [pmid: 30279122] 3. kahn en, muraszko km, maher co. prevalence of chiari i malformation and syringomyelia. neurosurg clin n am. 2015; 26(4):501-507. [https://doi.org/10.1016/j.nec.2015.06.006] [pmid: 26408058] 4. doberstein ca, torabi r, klinge pm. current concepts in the pathogenesis, diagnosis, and management of type i chiari malformations. r i med j (2013). 2017; 100(6):47-49. [pmid: 28564670] 5. yarbrough ck, powers ak, park ts, et al. patients with chiari malformation type i presenting with acute neurological deficits: case series. j neurosurg pediatr 2011; 7(3):244-247. [doi: 10.3171/2010.11.peds1097] [pmid: 21361761] 6. maher me, hutchison m, cusimano m, et al. concussions and heading in soccer: a review of the evidence of incidence, mechanisms, biomarkers and neurocognitive outcomes. brain inj 2014; 28(3):271-285. [doi: 10.3109/02699052.2013.865269] [pmid: 24475745] 7. meehan wp 3rd, jordaan m, prabhu sp, et al. risk of athletes with chiari malformations suffering catastrophic injuries during sports participation is low. clin j sport med 2015; 25(2):133-137. [doi: 10.1097/jsm.0000000000000107] [pmid: 24905537] 8. strahle j, geh n, selzer bj, et al. sports participation with chiari i malformation. j neurosurg pediatr 2016; 17(4):403409. [doi: 10.3171/2015.8.peds15188] [pmid: 26636249] original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license the business management training needs of south african biokineticists to ensure business sustainability mj lumb, mphil; k marais, mba school of management, iie’s varsity college, belmont office park, belmont rd, rondebosch, cape town, 7700, western cape, south africa corresponding author: mj lumb (michaeljameslumb@gmail.com) the profession of biokinetics is a specialised discipline in exercise therapy. the name is derived from two greek words: bio’ meaning life and ‘kinesis’ meaning movement. therefore, biokinetics means ‘life through movement’. [4] the healthcare industry currently finds itself undergoing rapid changes that are leading to an ever more competitive environment. professionals are continuously challenged with balancing the concepts of business management, knowledge development and business sustainability with patient quality of life while trying to maintain ethical integrity. [1,5,6,7,8] business management training needs for health and medical professionals are essential as many practitioners may find themselves in leadership and managerial positions within practices and multidisciplinary medical centres.[1] by upskilling medical and health professionals with business knowledge it may lead to an increase in local entrepreneurship which could benefit a struggling economy such as south africa. it may also lead to the reduction of professionals seeking work overseas if more local work opportunities are available.[5,9] to our knowledge, few studies around the world have determined the business management training needs of health and medical professionals and no study of this sort has been performed on south african biokineticists. similar studies have been performed on other health and medical professions around the world and in south africa. [1,5,6,7] these studies have displayed a need for a more in-depth approach to teaching business concepts to professionals such as chiropractors and audiologists. [1,5] table 1 tabulates the high to very high needs for south african biokineticists, south african audiologists and north american chiropractors [1,5]. the results of the above three studies are not directly comparable due to the current study using a 5-point likertscale (very low, low, moderate, high and very high) compared to the 4-point likert-scale used in the audiologist and chiropractic studies (very low, low, high, very high). however, the ranking of importance for the business management fields can be compared [1,5]. the question now arises whether there is sufficient business management training for biokineticists which equips them to run a successful and sustainable business. background: business management training is essential for success in the modern era. health and medical professionals are exposed to knowledge that allows them to treat pathologies. however, their training does not prepare them to manage their practices as businesses and in a sustainable, effective, and efficient manner. objectives: to investigate the business management training needs of registered south african biokineticists. methods: a quantitative and descriptive research design was used. sixty-nine registered biokineticists answered the emailed survey. the survey was sent out on two separate days, two weeks apart. participants could only answer the survey once. the survey was sent out by the biokinetics association of south africa (basa). the sample in this study consisted of both male and female participants who graduated between the years of 1985-2019. the survey consisted of demographic questions about their study methods. it also included a 5-point likert scale where a score of 1 indicated an exceptionally low need and a score of 5 indicated a very high need for corresponding business processes. the business processes included accounting, business sustainability, corporate social responsibility, ethics, financial management, human resource management, leadership and managerial decision-making, marketing, operational management, and strategic management. a final open-ended question on what other business management training the participant needed was asked at the end of the survey. results: combined high to very high needs (x≥4 on the likert scale) for the business management processes explored were: accounting: 28%, business sustainability: 33%, corporate social responsibility: 23%, ethics: 55%, financial management: 35%, human resource management: 29%, leadership and managerial decision-making: 43%, marketing: 41%, operational management: 39%, and strategic management: 33%. seventy-one percent of the participants who took part in the study suggested that they needed other business management training needs, providing suggestions in the final question. of the 71% of participants who answered this question, the most important requests identified included information technology (17%), taxrelated management and knowledge (19%) and medical aid training for icd-10 coding (13%). the other 51% of the participants that answered the final question provided suggestions that could be categorised into the areas of business already reported on in the likert scale. sixty-nine out of a possible ±1600 registered biokineticists who were basa members completed the survey. this represents a response rate of about 4%. conclusion: business management training needs exist for south african biokineticists. by addressing these needs, it may lead to improvements in overall patient care, practice management and small business growth which in return can lead to the socioeconomic stimulation of the country. keywords: administration, education, health professionals, knowledge, practice management, skills s afr j sports med 2021;33:1-5. doi: 10.17159/2078-516x/2021/v33i1a9220 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9220 https://orcid.org/0000-0001-7685-5003 https://orcid.org/0000-0002-4605-2530 original research sajsm vol. 33 no. 1 2021 2 methods study design a quantitative and descriptive research design was conducted with the use of an online-based survey. the survey was distributed via email by the biokinetics association of south africa (basa) to registered biokineticists. the first email was sent on the 11th of june 2020 and the second email was sent on the 17th of june 2020. participants were limited to one opportunity to answer the survey. the study was terminated on the 24th of june 2020. the study protocol was approved by the campus research postgraduate studies committee at the cape town iee’s varsity college campus. fig. 1 is a schematic illustration of the research design that was followed in the study. the population used in this study were south african biokineticists who were members of the biokinetics association of south africa (basa). a non-randomised convenience sampling method was implemented. participants had to be fully registered with the hpcsa and members of basa. intern biokineticists were excluded from the study. prospective participants were emailed an information letter and a link to the online-based survey. informed consent was built into the online survey. the survey could not be completed unless informed consent was given. potential participants had to read the information letter and agree to the study by initialising a required question: “do you consent to partake in the following study? if so, please type in your initials below (information & consent form above)”. if this question was not completed, the potential participant would not be able to proceed further with the survey. a sample of 69 individuals was included in descriptive reporting. the participants were taken from a wide graduation period. they were grouped according to the graduation period as detailed in table 2. ‘graduation period’ is defined as the time in which a participant graduated with their biokinetics degree. the year 2020 was not included as students still needed to complete a year of internship to fully qualify. study procedure participants were emailed an information letter which provided the details of the study and a link to the online-based survey. the online-based survey was designed by consulting previous literature and studies that explored similar needs amongst north american chiropractors and south african audiologists.[1,5] data collection methods the data collection method used in this study was an onlinebased survey that was sent to basa registered biokineticists via email. the survey was sent as a link to possible respondents who had to read the attached information letter and the consent form. the survey was created with microsoft forms. [11] respondents had to follow the instructions and answer the questions that followed. this type of data collection method was ideal for the current circumstances of practising social distancing due to covid-19. the method was also cost-effective for the researcher and it allowed the respondents to complete the survey in their own time. the first email was sent out on the 11th june 2020. a reminder email was sent out to on the 17th june 2020. the study was closed on the 24th june, which was two weeks after the initial email was sent. a coding technique was implemented to filter out participants who responded more than once. data collection tool the survey that was sent to basa registered biokineticists included questions about their graduation period. a 5-point likert scale was used for responses to questions on business training where 1 was very low, 2 was low, 3 was moderate, 4 was high and 5 was very high. there was an open-ended final question on any other business knowledge training. before sending out the survey, a pilot survey was conducted with multiple different professionals. this was done to receive a broad spectrum of feedback in order to eliminate as many errors as possible. the data collection tool was designed by consulting previous studies that explored similar topics in the medical field.[1,5,6] all survey questions were compulsory and none could be left unanswered. glossary accounting: the business process that is concerned and focused on managing, recording, reporting, and analysing financial transactions of an organisation [1]. business sustainability: the business process that concerns itself with the impact the organisation has on internal and external stakeholders. it is comprised of three main elements including social, environmental, and economic [2]. corporate social responsibility: the business process that is concerned with integrating business, social and environmental factors from the strategic level to all levels of the organisation so to achieve a sustainable future for present and future stakeholders [2]. ethics: the business process that concerns itself with ethical decision making and what is considered the correct thing to do at a given point in time. it takes into consideration contracts, laws, and regulations that govern and guide an organisation [1]. financial management: the business process that is focused on acquiring, investing, and managing all the resources of an organisation including tangible and non-tangible assets [1]. human resources management: the business process that is focused on the management of people within the organisation and the acquisition of new talent. it is also focused on developing and acquiring knowledge for the organisation, hiring, and firing employees and the development and implementation of the organisation's culture [1]. leadership and managerial decision-making: can be described as a complex ever evolving social theory where one or more influential people empower and guide skilled individuals towards achieving a common shared goal [3]. marketing: the business process that is focused on defining and selecting potential target markets. it is also concerned with the management of the product/service, pricing, and communication [1]. operational management: the business field focused on managing the processes that produce and distribute a service or product to the organisation's target market [1]. strategic management: the business process that is focused on identifying and navigating an organisation towards meeting its goals and objectives [1]. original research 3 sajsm vol. 33 no. 1 2021 statistical analysis the level of confidence for the research was set at 95% (p≤0.05). the research made use of descriptive statistics and measures of central tendencies, including means and standard deviations. it also included frequencies and ranking of the results. the data were analysed in microsoft excel with the use of its built-in data analysis addon pack. ranking is the sum of high and very high percentages. rank 1 is the highest knowledge need amongst south african biokineticists. equal high to very high knowledge needs were given equivalent ranking. results the distribution for the needs of the following business concepts is detailed in table 3. the final open-ended question asked if there were other business management training needs that were not mentioned in the survey or could not be categorised with the already mentioned business processes. the answers were examined by the researcher and categorised into three main categories: technology management (n=8, 17%), tax management (n=9, 19%), and icd/medical aid training (n=6, 13%). discussion the current study explored the business knowledge training needs for basaregistered biokineticists. even though the data presented was only descriptive, it provides insight into areas where the profession needs guidance and further education. this study can be used as a pilot for future studies that explore similar table 1. comparison of business knowledge training needs across studies business knowledge business knowledge training needs for south african biokineticists required practice management knowledge for south african audiologists [5] business training and education needs of north american chiropractors [1] need high and very high high and very high high and very high accounting 28 (8) 92 (3) 79 (6) business sustainability 33 (6) n/a n/a corporate social responsibility 23 (9) n/a n/a ethics 55 (1) 95 (2) 81 (5) financial management 35 (5) 92 (4) 83 (3) human resource management 29 (7) 89 (7) 89 (1) leadership 43 (2) 90 (6) 70 (7) marketing 41 (3) 96 (1) 82 (4) operational management 39 (4) 90 (6) 62 (8) strategic management 33 (6) 92 (5) 86 (2) data are displayed as percentage % (ranking) fig. 1. research design (adapted prisma flow diagram) (moher, liberati, tetzlaff, altman & the prisma group, 2009) [10] original research sajsm vol. 33 no. 1 2021 4 topics, as well as for the future development of the biokinetics curriculum. the importance of a successful medical, health and fitness industry in south africa cannot be underestimated as a driver for social and economic development.[12] an improvement in and development of the managerial skills of the practitioners may make them better suited to implement successful business strategies in addressing the burden of disease that impacts a developing country like south africa .[12] furthermore, the study may assist practitioners to have a more impactful and successful outcome when addressing the needs of the population if the limited scope and quality of management they are taught is addressed.[12] in accordance with previous studies, the survey was designed to determine the current needs of south african biokineticists across a broad spectrum of business processes.[1,5,6,7,8] the study included two newer schools of thought within the business environment, namely corporate social responsibility and business sustainability which are critical to the success of any modern business.[13] also, these two concepts were not explored in previous studies.[1,5,6,7] without a thorough understanding of these concepts, the practitioner may end up neglecting fundamental stakeholders and within their business itself.[13] by exposing health and medical professionals to concepts such as business sustainability and corporate social responsibility, practitioners can better position themselves to assist the country in addressing the initiatives of encouraging physical activity and healthy lifestyles.[12] it can also provide unique opportunities for practitioners to involve themselves in advising and managing government initiatives that are aimed at addressing chronic and lifestyle diseases, the type of facilities that are required, and the direction in which the industry should go.[12] biokineticists have a unique opportunity to evolve the profession and address the above-mentioned gaps in the market. large market demands are present in south africa for biokineticists; however, to successfully access these market demands the correct business knowledge, training and skills are required. [14,15] biokineticists are left with limited career choices within south africa, often finding themselves working for, or opening, private practices [14]. the prospect of succeeding with these options are slim in south africa, where the small business failure rate is between 70-80% [15]. limitations numerous limitations are present in the current study, such as the small sample size, non-randomised sampling implementation, the short duration of the study and the use of an online-based survey, which tends to have low response rates. however, this was the most suitable method due to the regulations in place to limit the spread of covid-19. the current study did not differentiate between practitioners that worked for practices, managed a practice, owned a practice, or were academics involved in research. furthermore, the study only included basa members which could have led to the omission of practitioners only registered with the hpcsa. in future studies, researchers should attempt to conduct randomised sampling and to apply inferential statistics and inferences from the sample to the population. furthermore, it will be useful if future studies implement a mixedmethods data collection technique to gain more insight into the type of training and knowledge needed by practitioners. the inclusion of biokineticists not registered with basa is also recommended. future studies should explore associations between variables, including where practitioners graduated from and the business knowledge needs required, as well as the year in which they graduated. furthermore, future studies table 2. graduation period count (n) graduation period (years) count of graduation period (n) before 1980 0 1985-1989 1 1990-1994 2 1995-1999 2 2000-2004 15 2005-2009 14 2010-2014 14 2015-2019 21 total count (n) 69 table 3. distribution and ranking of business knowledge training needs amongst south african biokineticists, rated on a 5-point likert scale. likert scale rating business knowledge need very low (1) low (2) moderate (3) high (4) very high (5) ranking ethics 7 (5) 12 (8) 26 (18) 30 (21) 25(17) 1 leadership and managerial decisionmaking 9 (6) 22 (15) 26 (18) 30 (21) 13 (9) 2 marketing 6 (4) 17 (12) 36 (25) 29 (20) 12 (8) 3 operational management 10 (7) 19 (13) 32 (22) 25 (17) 15 (10) 4 financial management 3 (2) 36 (25) 26 (18) 25 (17) 10 (7) 5 strategic management 10 (7) 33 (23) 23 (16) 25 (17) 9 (6) 6* business sustainability 12 (8) 22 (15) 33 (23) 25 (17) 9 (6) 6* human resource management 12 (8) 26 (18) 33 (23) 25 (17) 4 (3) 7 accounting 19 (13) 19 (13) 35 (24) 23 (16) 4 (3) 8 corporate social responsibility 15 (10) 23 (16) 39 (27) 17 (12) 6 (4) 9 data are displayed as percentage % (n). ranking is the sum of high and very high percentages.* tied rankings between strategic management and business sustainability. original research 5 sajsm vol. 33 no. 1 2021 should perform in-depth analyses of the current biokinetics curriculum to determine what business skills are being taught. conclusion identifying and addressing shortfalls in business knowledge training for healthcare professionals, such as biokineticists, may lead to improvements in overall patient care and practice management. this may result in the growth of small practices, becoming sustainable and successful in a modern business environment.[14,15] furthermore, by addressing the abovementioned gaps in education and knowledge, biokineticists may have an opportunity to evolve and implement themselves in addressing the larger socioeconomic and health-related issues. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. acknowledgements: the authors wish to thank the participants for their contribution to the study. author contributions: mjl was the primary researcher. all the authors were involved in the study’s design, implementation, and review process. references 1. henson s, pressley m, korfmann s. business training and education needs of chiropractors. j chiropr educ 2008; 22(2):145-151. [doi: 10.7899/1042-5055-22.2.145][pmid: 19043535] 2. agudelo m, jóhannsdóttir l, davidsdóttir b. a literature review of the history and evolution of corporate social responsibility. int j corp soc responsib 2019; 4(1): 1-23. [https://doi.org/10.1186/s40991-018-0039-y] 3. winston e, patterson k. an integrative definition of leadership. ijl s 2006;1 6-66. 4. ellapen tj, strydom gl, swanepoel m, et al. biokinetics: a south african health profession evolving from physical education and sport, sport and exercise science, matjaz merc. intechopen 2018;16-27 [doi:10.5772/intechopen.73126] [https://www.intechopen.com/books/sport-and-exercisescience/biokinetics-a-south-african-health-profession-evolvingfrom-physical-education-and-sport] 5. breytenbach d, kritzinger a, soer m. audiology practice management in south africa: what audiologists know and what they should know. sa j commun disord 2015; 62(1):114. [doi: 10.4102/sajcd. v62i1.114][pmid: 26809158] 6. crow sm, hartman sj, brockmann en, et al.. the educational needs of healthcare managers and executives in the key strategic areas of healthcare. hosp top 2002; 80(3): 16-20. [doi: 10.1080/00185860209597998][pmid: 12471880] 7. henson s, burke d, crow s et al. legal and regulatory education and training needs in the healthcare industry. jonas healthc law ethics regul 2005;7(4): 114-118. [doi: 10.1097/00128488-200510000-00007][pmid:16331074] 8. kennet pa, henson sw, crow sm et al. key tasks in healthcare marketing: assessing the importance and current level of knowledge. j health hum serv adm 2005; 27(4): 414-427. [pmid:16318012] 9. mlambo vh, adetiba tc. effects of brain drain on the south african health sector, analysis of the dynamics of its push factors. j econ behav stud 2017; 9(4): 62-72. [doi:10.22610/jebs. v9i4.1822] 10. moher d, liberati a, tetzlaff j, et al.. preferred reporting items for systematic reviews and meta-analyses: the prisma statement. plos med 2009; 6(7): e1000097. [doi:10.1371/journal. pmed1000097][pmid: 19621072] 11. microsoft corporation, 2020. microsoft forms, available at: https://www.microsoft.com/en-za/microsoft-365/onlinesurveys-polls-quizzes. 12. draper e, grobler l, killian g, et al. an inventory of the south african fitness industry. sa j sports med 2006; 18(3): 93-104. [doi: doi: 10.17159/2078-516x/2006/v18i3a240] 13. d’amato a, henderson s, florence s. corporate social responsibility and sustainable businessa guide to leadership tasks and functions. greensboro, nc: centre for creative leadership 2009, 1-91. 14. moss sj, lubbe ms. the potential market demand for biokinetics in the private healthcare sector of south africa. sa j sports med 2011; 23(1): 14-19. [doi: 10.17159/2078-516x/2011/v23i1a365] 15. fatoki o. the causes of the failure of new small and medium enterprises in south africa. mediterr j soc sci 2014; 5(20): 922927. [doi: 10.5901/mjss. 2014.v5n20p922] https://doi.org/10.1186/s40991-018-0039-y volume 6 • number 1 • july 1999 the south african journal of sports medicine the official publication of the south african sports medicine association r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ahead in cox-2 selectivity with a 3 j/eak tkackrecokd. i i ii ii i ■ o n c e d a i l y w o e / e inflammatory pain relief and mobility in any body's language. boehrinaer ^oplicant details: ingelheim pharmaceuticals (ptyi ltd. co. beg no 6&/o8610/o7 "™“ j | r l(_ _ | h q i r | t 407 pine avenue. randburg; tel (011) 886-1075; fax <cn 11 787 ■57tjt5/b0g 520s i n g e i n e i m jgejmotke 7.5 mg tablet each tablet contains 7.5 mg metoxicam beg no 39/3 1/421 407 pine avenue, sandburg: tel (011) 886-1075: fax (01i i t87-3766/b8g 5205 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) exercise science and e ditorial a few weeks ago i received a late night telephone call from a distraught father of an adolescent elite athlete who had been informed 3 days before the call to me that his son had tested positive for a stimulant at a national sports com peti­ tion. the stimulant was one that is commonly found in medication used to treat upper respiratory tract infections. this young athlete, who is not yet o f legal age, complained ol' upper respiratory tract symptoms a few days before a national competition and went to see a specialist for treatment. his main concern was not to let down his team during the forthcoming competition. trusting the treating doctor, he took whatever medication was required to get well before competing. a few days later he tested positive for the stimulant. this young athlete now l'accs a hearing, and if found guilty his team, whom he did not want to let down, may lose its medal. the long-term consequences on this young superstar’s ath­ letic career, and more importantly the psychological trauma on this child, cannot be quantified at this stage. it is sad that an incident such as this still occurs in a country that prides itself on its professional approach to sport. o f particular concern is the fact that this young ath­ lete was not aware o f substances that are banned in his sport, and secondly that he put his trust in a specialist doctor for treatment o f an illness a few days before a national event. at what age should an athlete be expected to lake full responsibility for not taking a banned substance? who takes responsibility for such a young athlete? these circum stances once again emphasise the important role that medical staff play in the sports medical care o f athletes at this level. surely the time has come for the care o f athletes to be placed in the hands o f well-trained, professional medical staff who are able to deal with and advise athletes on issues such as doping in sport. this incident is a classical case o f ‘accidental dop­ ing’ . it illustrates clearly that not enough is being done to educate medical staff, coaches and athletes at all levels, but particularly young athletes, on the issues surrounding doping in sport. i would like to see the authorities responsible for drug testing allocate more time and financial resources to educating athletes as well as medical staff in order to prevent a repeat o f this unfortunate incident. a vigorous information campaign among athletes prior to participating in events where drug testing is likely to take place is required. coaches and parents (in the case o f minors) should be well informed by the authorities before sports events or outsports medicine resource centre of-competition testing campaigns are undertaken. it is also important that medical personnel who treat ath­ letes are fully aware o f the rules and regulations per­ taining to drug use in sports. sports medicine, as a discipline, has evolved at an incredibly fast rate over the last decade. the core body o f knowledge in this field has increased to such an extent that there is even discussion about sub-special­ isation within sports medicine. in south africa, the interest in postgraduate training courses in spoils medicine has paralleled this growth, and it is not inconceivable that sports medicine will be a registered specialty in south africa within the next 3 years. professional athletes require professionals to care for them. currently medical doctors with a postgraduate sports medicine qualification are not recognised for their important and responsible role. often this lack of professional recognition is not only from colleagues, but also from sports authorities; consequently sports medicine professionals in south africa are not remu­ nerated adequately for their services. the professional risk that a doctor takes in caring for a professional ath­ lete is substantial and is probably as high, if not high­ er, than the professional risk that an obstetrician is exposed to in performing a delivery. the south african journal o f sports medicine is an important tool for continued medical education. this first edition o f the journal for 1999, although slightly delayed due to the fact that we had to find a new pub­ lisher, contains valuable information on a number o f topics in sports medicine. the position statement pub­ lished by the international sports medicine federation on diabetes mellitus and exercise will be o f value to any professional who cares for athletes with diabetes mel­ litus. this edition also contains a number o f research articles pertaining to sports performance, and there are two papers that focus on heart rate responses dur­ ing running and cricket. on behalf o f the editorial board i would like to thank the south african medical association's publica­ tion division for their willingness to assist us in the publication o f this journal. i am convinced that their involvement will add considerable value to the journal, and we look forward to a long-term relationship with them. martin p schwellnus editor-in-chief sports medicine july 1999 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the south african journal of sports medicine volume 6 • number 1 • july 1999 editor-in-chief p r o f m p s c h w e lln u s u n iv ersity o f c a p e t ow n s e n i o r a s s o c ia t e e d it o r s p r o f m m a rs u n iv ersity o f n atal d r m l a m b e r t u n iv e rsity o f c a p e t ow n n e w s e d it o r d r p m a cf a rla n e g e n e r a l p r a ctitio n e r, c a p e t ow n e d i t o r i a l b o a r d p r o f y c o o p o o u n iv e rs ity o f d u r b a n w estviu e d r k m y b u rg h u n iv e rs ity o f s t e lle n b o s c h p r o f t d n o a k e s u n iv ersity o f c a p e t ow n p r o f g r o g e r s u n iv e rs ity o f w itw a te rsra n d p r o f k v aug han u n iv e rs ity o f c a p e t ow n a d v e r t is in g s a m e d ic a l a s s o c ia tio n t e c h n ic a l e d i t o r j u lia c a s c io la s a m e d ic a l a s s o c ia tio n production w ayne p r e s s s a m e d ic a l a s s o c ia tio n d e s ig n & l a y o u t n ik k i s e a r le s a m e d ic a l a s s o c ia tio n p u b l is h in g s a m e d ic a l a s s o c ia tio n h e a lth a n d m e d ic a l p u b lis h in g g r o u p 1 4 c e n tra l s q u a r e , p in e la n d s 7 4 0 5 p riv a te b a g x i , p in e la n d s 7 4 3 0 t e l ( 0 2 1 ) 5 3 1 -3 0 8 1 , fa x ( 0 2 1 ) 5 3 1 -4 1 2 6 r e p r o & p r in t in g in c e c a p e contents editorial j mp schwellnus review article j.............................................................. the pathophysiology of compartment syndromes: microcirculatory compromise as a cause of exercise induced limb pain gp hadley, m mars | original research articles i..................................... a quantification of competition-induced increase in heart rate during 10, 21 and 42 km races wm tucker, td noakes, mi lambert improved time-trial performance after tapering in well-trained cyclists a bosch, a thomas, td noakes heart rate response of young cricket fast bowlers while bowling a six-over spell r a stretch, m i lambert .6 i clinical case report ..................................... the consequences of the female athlete triad in a mature woman runner: a case report i k micklesfield, kjl myburgh .20 position statement .23 diabetes mellitus and exercise international sports medicine federation (fims) the ioc olympic prize .25 the editor the south african journal o f sports medicine po b ox 115 newlands 7725 tel: 021 686 7330 fax: 021 686 7530 articles m ay b e rep rodu ced w ith ou t th e w ritten con sen t o f th e publishers. 2 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) review article the pathophysiology o f compartment syndromes: microcirculatory compromise as a cause o f exercise-induced limb pain gp hadley1 (frcs) m mars2 (mb chb) 1 d e p a r tm e n t o f p a e d ia tr ic s u rgery, u n iv e rsity o f n atal m e d ic a l s c h o o l, d u r b a n 2 d e p a r tm e n t o f p h y siolog y , u n iv e rsity o f n atal m e d ic a l s c h o o l, d u r b a n abstract this paper summarises the pathophysiology o f raised intracompartmental pressure (tcp) and its effects on capillary and hence nutrient blood flow. the important relationship o f icp to mean arterial pressure and diastolic pressure is discussed, as are , the principles o f diagnosis and management o f raised ice in order to reduce morbidity there is a need to raise awareness o f the consequences o f raised icp, and to make a diagnosis o f raised icp rather than wait for the functional impairment o f a compartment syndrome to occur. introduction the purpose o f this contribution is to introduce the concept o f tissue pressure within a closed compart­ ment, to review the basic physiology o f capillary blood flow and to relate these to the events that may lead to exercise-induced limb pain o f vascular origin. there; are two interrelated concepts, namely those o f increased tissue pressure and reduced inflow pressure; although discussed as separate issues, these in fact usually occur synchronously in practice. the apparent paradox o f cell death and gangrene occurring in a limb in which bounding pulses can be felt, is emphasised. the effects o f an increase in tissue pressure and arterial stenosis on capillary flow are dis­ cussed. arterial disease, particularly stenosis, is often bought o f as the prerogative o f the elderly, but recent^orrespondence: 'rofessor gp hadley >epartment o f paediatric surgery university o f natal medical school rivate bag 7 ongella 4013 pi: 031 260 4227 j x : 031 260 4572 -mail: hadley@med.und.ac.za ly the recognition o f entrapments, injuries and congen­ ital abnormalities has increased awareness o f stenoses in young active individuals. raised compartment pres­ sures and compartment syndromes occur in a myriad o f clinical situations and awareness is essential for diag­ n o s i s . 1'4 -7 -9 1 2 . ^ , 1 7 2 0 ,2 2 ,2 5 2 7 ,2 9 no practitioner can afford to be unaware o f the concepts involved. pathophysiology arterial stenosis any lesion occupying space in a vessel will alter the dynamics o f blood flowing past the lesion. the energy wasted in turbulent flow causes a loss in potential ener­ gy that is measured as a fall in blood pressure distal to the stenotic lesion. this reduction in blood pressure results in a reduction in the pressure at the arteriolar end o f the capillary bed and therefore relative hypo­ perfusion o f the exercising muscle distal to the stenosis.24 during exercise there is an increased demand for oxygen that is normally met by increased muscle blood flow. i f this cannot be achieved because there is a prob­ lem with inflow, then claudication may result. further, as muscle volume increases during exercise and is con­ tained within a relatively inelastic osseofascial com ­ partment, there is a tendency for the compartment pressure to rise. the relationship between inflow pres­ sure and tissue pressure is critical in determining the adequacy o f tissue perfusion and cellular oxygenation. compartment syndrome matsen16 has defined a compartment syndrome as damage to the cells caused by increased tissue pres­ sure within a compartment, resulting in loss o f func­ tion. we do not want to wait for loss o f function before recognising and treating changes in tissue pressure, and it is our aim to diagnose an increasing compart­ ment pressure and institute treatment before a com ­ partment syndrome occurs.14 increased tissue pressure in itself is not diagnostic o f inadequate cell nutrition, rather it is tissue pressure relative to the inflow pres­ sure that is crucial.828 inflow pressure to a muscle group can b e low, even in the presence o f systemic hypertension, i f there is a lesion in the axial artery that causes a loss o f pressure. aorts medicine july 1999 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:hadley@med.und.ac.za muscle nutrient blood flow and the effects of stenosis and raised intracompartment pressure any fluid, including blood, wall only flow along an energy gradient. to all intents and purposes this means a pressure gradient. although there are some situations where blood will move against an apparent pressure gradient (for example, when standing the blood pressure in the foot will be higher than the pres­ sure in the aorta), the kinetic and potential energy of the blood is sufficient to overcome this.24 therefore for the purposes o f this discussion, in order for blood to circulate throughout the body there must be a gradual fall in blood pressure from the left ventricle, through the capillary beds and the venous system, to the right ventricle. the left ventricular pressure is reflected in the systolic blood pressure. the diastolic pressure reflects the peripheral resistance. it is convenient to think in terms o f the mean arterial pressure (map), which is an expression o f the effective pressure generat­ ed by pulsatile flow. it is calculated as the diastolic pressure plus one-third o f the pulse pressure. blood pressure is affected by the stroke volume, i.e. the amount o f blood that must b e moved, and the peripheral vascular resistance against which the blood must b e pumped. as peripheral vascular resistance increases, the blood pressure must increase to main­ tain the same flow. i f the blood pressure cannot be increased then flow must fall. at a micro-circulatory level the same principles hold. the driving force, or inflow' pressure to the cap­ illary bed, must b e lower than the systemic blood pres­ sure, but is derived from it. regional inflow pressure may b e reduced by a systemic hypotension or by the presence o f a proximal stenotic lesion. the resistance to flow at this level is determined by the calibre and length o f the capillaries and the pressure gradient across the capillary b ed .24 as capillaries are a single cell thick and have little inherent strength, their diam­ eter is governed by the tissue pressure around them.2 in addition to these factors the function o f the capillary is to allow nutrients, including oxygen, to diffuse into the cells. for this to occur, starling’s hypothesis sug­ gests that fluid leaves the arterial end o f the capillary and fluid is returned at the venous end. this is again, like all fluid shifts, a pressure-depen­ dent process, with the driving forces being the arterio­ lar capillary pressure and the osmotic pressure o f the interstitial fluid, and the opposing forces being the tis­ sue pressure and the oncotic pressure that tends to keep fluid within the vessel.24 anything that disturbs this balance wall interfere with cell nutrition. therefore reducing the perfusion pres­ sure by either lowering arteriolar pressure or increasing venular pressure, will tend to reduce flow. increasing the tissue pressure or lowering capillary pressure wall therefore secondarily affect oxygen delivery'. increasing tissue pressure will also tend to cause collapse o f the vessel, a tendency that is minimised by a reflex increase in venous pressure.3 while keeping the vessel open this also has the effect o f reducing the pressure gradient and thereby reducing flow". obviously this will b e maximal in situations where there is no flow. no flowr will occur when the pressure gradient is reduced to zero. in fact flow' ceases before this when the pressure difference is so low that the thickness o f the blood becom es an important factor. the rheologi cal features o f blood are affected by many factors, including cell count and protein content, and in many clinical situations reducing the haem atocrit will improve oxygen delivery' to the tissues by improving the flow'.24 any tendency to an increase in tissue pressure is usually accommodated by' increase in volume o f the tis­ sue, or swelling. compromise o f capillary blood flow' only occurs in those anatomical areas w'here swelling is not possible, or can only occur to a limited extent. a prime example is the intracranial haematoma that in the adult cannot be accommodated by increasing the volume o f the skull, so pressure in the head rises. similarly, any increase in pressure within an osseo-fas cial compartment cannot b e accommodated by increas­ ing the volume o f the compartment, consequently compartmental pressure will rise. in fact within any fascial space there is potential for a harmful increase in pressure, and the importance o f micro-compartments, such as within the epineurium, should not be forgot­ ten.23 as the microcirculatory pressures are much low'er than pressures in the axial vessels, it is possible, in fact usual, to have normal axial artery pulses despite com ­ plete cessation o f flow in the capillary b eds.13 this is an important concept — the muscles o f a leg may b e gan­ grenous in the presence o f arterial pulses. time is also an important parameter. the tolerance o f tissue to ischaemia is varied, wdth neuronal tissue being most sensitive.2,5 in clinical practice, therefore, early' signs o f ischaemia are often neuronal, such as paraesthesia or anaesthesia. in summary, the pressure gradient across a capillary' b e d is small, much less than mean arterial pressure, but derived from it. i f the system ic pressure is low' ered, then the pressure gradient across the capillary bed wi 11 be low'ered. capillary blood flow will stop w'hen tissue pressure exceeds or comes close to arteri­ olar inflow' pressure. at this stage the axial artery puls­ es wall still be clearly palpable. when capillary blood flow' stops, cell death will ensue within a short time period that is dependent on the type o f tissue involved, but w'hich is shortest in neural tissue. management management can b e aimed at either elevating the per­ fusion pressure by resuscitating the individual, or at reducing the tissue pressure by' decompression o f the compartment, or both. definitive management o f an arterial lesion by resection, bypass or disobliteration may be necessary for ultimate resolution o f the prob­ lem. 4 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) assessment may be clinically difficult. particularly troublesome are children in whom it is difficult to elic­ it clinical signs or in whom co-operation is a problem. in patients with spinal injuries, be they traumatic or iatrogenic injuries such as those resulting from epidur­ al anaesthesia, signs may be difficult to elicit. when the limb is encased in plaster, examination may be lim ­ ited.21 for these reasons invasive compartment pres­ sure monitoring is advised; the techniques and indices for intervention wi 11 be discussed by other authors. management is usually described in terms o f surgi­ cal decompression, but a lot can be done while waiting for surgery, which may occasionally obviate the need for an operation. this has been aptly described as ‘first aid for hypoxic cells’ . all circumferential dress­ ings should be removed, the limb should be kept at heart height as elevation decreases the arterial perfu­ sion pressure, the patient should be resuscitated with crystalloid to restore volume and reduce haematocrit, and maximum oxygenation should be assured.13 1 compartment pressure can b e measured serially dur­ ing these manoeuvres and compared with map we believe that in children fasciotomy should b e consid­ ered when compartmental pressure reaches map 3 0 mmhg, and in adults when it reaches diastolic 20 mm h g.14 time is o f the essence and such patients should be regarded as true surgical emergencies. r e f e r e n c e s 1. anglen j. baiiovetz j. compartment syndrome in the well leg resulting from fracture-table positioning. clin orthon 1994301 239-42. 2. ashton h. the effect o f increased tissue pressure on blood flow clin orthop 1975; 113: 15-26. 3. belcaro g, vasdekis s, nicolaides an. evaluation o f skin blood flow and venoarteriolar response in patients with diabetes and periph­ eral vascular disease by laser doppler flowmeti-v. anqioloqu 1989 4 0 :95 3 -7 . ' 4. block it, dobo s, kirton oc. compartment syndrome in the criti­ cally injured following massive resuscitation: case reports j trauma 1995; 39: 787-91. 5. brotman s, browner bd, cox ef. mas trousers improperly applied ) causing a compartment syndrome in 1 owcr -cxtre mi tv trauma. j trauma 1982; 22: 598-9. 6. brown rl, greenhalgh dg, kagan rj, warden gd. 'hie adequacy of limb escharotomies-fasciotoinies after referral to a maior bum ecnter. j trauma 1994; 37: 916-20. 7. handler eg. superficial compartment syndrome o f the foot after infiltration o f intravenous fluid. arch phils med rehabil 1990 71(1): 58-9. 8. ileppenstall rb, sapega a a, lzant t, fallon r, shenton d, park ys, chance b. compartment syndrome: a quantitative study o f high energy phosphorus compounds using 31p-magnetic resonimce spec­ troscopy. j trauma 1989; 29: 1113-9. 9. janzing ii, broos i! ronmcas e compartment syndrome as com ­ plication of skin traction, in children with femoral fractures a cta chir belg 1996; 96(3):135-7. 10. manoli a 2nd, fakhouri a, j, weber tg. concurrent compartment syndromes o f the foot and leg. foot ankle int 1993; 14: 339-442. 11. mars m. hand’s up? a preliminary' study on the effect o f post-oper­ ative hand elevation. j hand surg 1988; 13b: 430-3. 12. mars m, brock-utnc jg. the effect o f tourniquet release on intra compartmcntal pressure in the bandaged and unbandaged limb j hand surg |br] 1991; 16: 318-22. 13. mars m, hadley ge raised mtracompartmental pressure and com ­ partment syndromes. injury 1998; 29: 403-11. 14. mars m, hadley ge raised compartmental pressure in children: a basis for management. injury 1998; 29(3):183-5. 15. mars m. tladlcy gp, aitehison jm. direct mtracompartmental pres­ sure measurement in the management o f snakebites in children s afr med j 1991; 80: 227-8. 16. matsen fa 3rd. compartmental syndrome. an unified concept clin orlhop 1975; 113: 8-14. 17. minkowitz b, busch mt. supracondylar humerus fractures. current trends £uid controversies (review). orthop clin north am 199425 581-94. 18. naito m, ogata k. acute volar compartment syndrome during skele­ tal traction in distal radius fracture. a case report. clin orthon 1989; 241: 234-7. 19. perry mo, thaler er, shires gt. management o f arterial injuries ann surg .1971; 173: 403-8. 20. pinltowski j i ,, weiner ds. complications in proximal tibial osteotomies in children with presentation o f technique. j pediatr orthop 1995; 15: 307-12. 2 1 -price c, ribciro j, kinnebrew t. compartment syndromes associ­ ated with postoperative epidural analgesia. a case repoit. j bone joint surg am 1996; 78: 597-9. 22. qvist .1, pcterfreiuid ra, perlmutter gs. transient compartment syndrome o f the forearm after attempted radial artcrv cannulation a neslh analg 1996; 83(1): 183-5. 23. rydevik b, lundborg g, bagge u. effects o f graded compression on intrancural bloodflow. j hand surg 1981; 6(1): 3-12. 24. sumner' ds. essential haemodynamic principles. in: rutherford rb, ed. vascular surgery. 4th ed. philadelphia: wb saunders 1995:18-44. 25. sundararuj gd, mani k management ofvolkmann’s ischaemic con­ tracture o f the upper limb. j hand surg [br.l 1985; 10: 401-3. 26. sutin km, longaker mt, wahiander s, kasabian ak, capau em, acute biceps compartment syndrome associated with the use o f a noninvasive blood pressure monitor. anesth analg 1996; 83: .1345-6. 27. tomctta p 3rd, templeman d. compartment syndrome associated with tibial fracture. in: american academy o f orthopaedic surgeons, ed. instr course lect 1997; 46: 303-8. 28. whitesides te, haney tc, jmorimoto iv, harada 11. tissue pressure measurements as a determinant for the need o f fasciotomv. clin orlhop 1975; 113: 43-51. 29wright r, reynolds sl, i\acli islicim b. compartment svnclromc secondary to prolonged mtraosseous infusion. pediatr emern care 1994; 10: 157-9. □ sports medicine july 1999 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a quantification o f competition-induced increase in heart rate during 10, 21 and 4-2 km races original research article wm tucker (bsc (med) (hons) exercise science) td noakes (mb chb, md, facsm) mi lambert (phd) m r c /u c t b io e n e r g e t ic s o f e x e r c is e r e s e a r c h u nit, d e p a r tm e n t o f p h y siolog y , u n iv e rs ity o l c a p e lo\vn m e d ic a l s c h o o l, s p o r ts s c ie n c e in stitu te o f s o u th a fr ic a abstract objective. our previous study has shown that, at any running speed, heart rates (hrs) are higher during competition than during training. the aim o f this study was to determine whether this com petition-induced increase in h r (hrjjfi) was affect­ ed by race intensity or perceived effort (luring the race. design. male runners training at least 60 km /wk underwent a maximal oxygen consum ption ( v u test 4 days before a 10 km (n = 6), 21 lan (n = 6) or 42 km (n = 5) race. two days before the race, subjects underwent a track test to determme the relationship between running speed and h r under non-competitive conditions (r = 0.98 ± 0.01). results. the average h r during the 10, 21 and 42 km races were 163 + 13, 166 ± 10 and 156 ± 6 beats/m in respectively, representing 90 ± 5, 93 ± 4 and 84 ± 4% o f laboratory-derived maximum h r (h r ,„j (p > 0.05). the subjects ran the 10, 21, and 42 km races at 74 ± 5, 75 ± 4 and 64 ± 7% o f peak treadmill running speed. the tlr(nn for the 10, 21 and 42 km races were 20 + 7, 15 + 7 and 19 ± 13 beats/m in respectively. the subjects’ perception o f fatigue measured after the track test and after each race were not different. conclusions. hrs during competition are higher than hrs at the same speed in a non-competitive situation. this hrtllft is independent o f racing speed and cannot be explained by the perceived fatigue measured immediately after the race. in conclusion, hr measured during competitive exercise is not an accurate measure o f exercise intensity. correspondence: ml lambert mrc/uct bioenergetics o f exercise research unit sports science institute o f south africa po box 115 newlands 7725 tel: 021 686 7330 fax: 021 686 7530 e-mail: mlambert@sports.uct.ac.za introduction in a previous study it was found that runners’ heart rates (hrs) in 10 and 21 1cm competitive races were higher than their h rs at similar running speeds d in ­ ing training (hr^n)-14 this study raised two issues. firstly, h r monitors are used widely by athletes during competition. many o f these athletes measure their firs during competi­ tion in order to select an appropriate exercise intensity for that event. but the athlete will run slower than expected during a race should a racing target h r be calculated on a h r determined during training. indeed, this very effect and its negative consequences on competitive athletes has already been documented in the lay press." secondly, several factors including work load,1 time o f day,11 state o f fitness,4 dehydration,7 plasma vol­ um e,12 duration o f exercise6 and temperature” 10 may affect h r during exercise. however the mechanism causing the hr,ui1 is not known. nor has the extent o f the hr,,a-,been quantified. a b etter understanding o f this phenomenon has practical application for com pet­ itive athletes and will contribute to a better under­ standing o f the physiological mechanisms that affect h r during competition. accordingly, the aims o f this study w e r e to deter­ mine the itr,liir in runners in competitive races over v a r y i n g race distances and to determine whether this increase in competition hr was affected by race inten­ sity or perceived effort before and during the race. methods subjects the study was approved by the ethics and research committee o f the university7 o f cape town. eight long­ distance runners who were training at least 60 km /w k were recruited for each o f 3 races (10 km, 21 km and 42 km). informed consent was obtained from all sub­ jects once the testing protocols had been explained. study design subjects were familiarised with all testing equipment • in the orientation phase o f this stud}’. thereafter 4 days before the race each subject underwent a maxi­ mum running test on a treadmill during which maxi­ 6 sports medicine juey 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:mlambert@sports.uct.ac.za mum oxygen consumption (v 02max) and maximum hr (hrm,,,) were determined. two days before the race subjects ran on an indoor track to determine their hwrunning speed relationship in non-competitive cir­ cumstances. all laboratory and field tests were con­ ducted between 5:30 and 8:00 a.m. to coincide approximately with the time o f day during which the races were to be held. during each race runners wore h r monitors (vantage xl, polar electro oy, kempele, finland) that recorded hrs continuously and split times for each kilometre. these data were then retrieved from the h r receiver after the race via an interface to a com ­ puter (polar electro oy, kempele, finland). following each laboratory field test and race the perceived level o f fatigue o f each subject was also evaluated. treadmill test after a 5-minute warm-up, subjects started running on the treadmill at 12 k m /h. the treadmill speed was increased by 0.5 k m /h every 30 seconds. the test was terminated when the subject was unable to maintain the speed o f the treadmill belt. each subject breathed through a rubber mask that covered his nose and mouth. the expired air was directed to 0 2 and c 0 2 analysers (oxyconsigma, mijnhart, netherlands) for the measurement o f oxygen consumption (v 02), carbon dioxide production (c 0 2) and respiratory exchange ratio (rer). the highest v 0 2 measured during the test was recorded as the v 0 2max. the equipment was calibrated before each test with a hans rudolph 3 litre syringe and a standard gas o f known concentration. h r was recorded throughout the test using a vantage xl h r monitor. track test after a standard warm-up, subjects ran 1 000 m at a submaximal pace on an indoor tartan track. the start­ ing pace was calculated to be 10 s/km slower than the subject’s current 5 km racing pace. each subject kept his running speed constant by pacing him self with a researcher who blew-a whistle at regular intervals coin­ ciding with the time the subject should have been at respective 100 m marks on the track. after a rest period o f 2 minutes, the subject ran another 1 000 m, this time 10 seconds faster. this pattern was repeated until the subjects were unable to maintain the required running pace. the subjects usually completed 5 or 6 km before the onset o f fatigue. after the test each sub­ je ct s average h r for the last 60 seconds o f each kilo­ metre, and the average running speed for each kilometre, were calculated. then the line o f best fit between hr and running speed was calculated using a linear regression analysis. the ambient temperature during the test was between 19 and sox. race subjects wore h r monitors while competing in 10, 21 or 42 km races. subjects were instructed to record the time splits for each kilometre by pressing the appro piiate button on the h r monitor receiver. the h r was recorded every 5 seconds during the 10 and 21 km races and every 15 seconds for the 42 km race. the average h r and average running speed were calculat­ ed for each kilometre during the race. the temperature for the duration o f the 10 km race was 19°c, between 16 and 19°c for the 21 km race and 20 °c at the end o f the 42 km race. measure of fatigue the subject’s perception o f fatigue was evaluated after each indoor running test and race according to the rose/n oakes running fatigue scale (0 = sluggish, exhausted, unable to run — 10 = best ever).8 body composition subject’s percentage body fat was predicted using the dumin and womersley anthropometric technique.3 statistics descriptive statistics are presented as the mean ± the standard deviation (mean ± sd). a line o f best fit was calculated between hr and running speed in the field test. the pearson’s correlation coefficient was calculat­ ed between these variables. the equation established for the relationship between h r and running speed for each subject was used to calculate his predicted hr based on the racing running speed. the difference between the subject’s h r measured in the race and the hr predicted from the regression equation was deter­ mined using a paired t-test. a spearman’s ranked test was used to determine relationships between the fatigue scores and hr(|ifi. statistical significance was accepted when p < 0.05. results hr data were available for 6 subjects for the 10 and 21 km races and for 5 subjects for the 42 km race. the other subjects had poor fir recordings during the races as a result o f malfunctioning h r monitors, and were excluded from further analysis. general characteristics and laboratory data o f the subjects participating in each race are shown in table i. the relationship between h r and running speed determined in the field test under non-competitive table i. general characteristics and laboratory data o f subjects participating in the 10, 21 and 42 km races (values expressed as mean ± sd) variables 10 k m 21 kin 4 2 kmll (jv = 6 ) cv= 5 ) age (years) 3 6 .8 ± 4 .8 3 6.0 ± 4.3 3 6.2 ± 4 .9 m ass (kg) 7 5.8 ± 13.9 7 5 .5 ± 13.0 6 9 .0 ± 12.9 stature (cm ) 1 7 7 .8 ± 9 .6 17 8 .7 ± 9 .5 17 2 .4 ± 8.0 p er ce n t fat 14.5 ± 4 .4 1 5 .9 ± 4 .6 1 2 .9 ± 4 . 0 v o a (m l o v k g /m in ) 5 3 .6 ± 8.1 5 3 .7 ± 8.1 5 3 .8 ± 10.5 hrfuax (b e a ts /m in )) 182 ± 8 181 ± 10 181 ± 7 it r s (k m /h ) 18.8 ± 1.3 1 8 .4 ± 1.3 18.9 ± 1.7 rer 1.05 + 0.05 1.05 ± 0.05 1.09 ± 0.06 f i r s p ea k treadm ill running sp e e d ; r e r = respira tory exchange ratio. sports medicine july 1999 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) conditions was r = 0.98 ± 0.01. (mean ± sd). the average running times for the 10, 21 and 42 km races were 43:25 ± 5:15, 92:48 ± 7:51 and 212:03 ± 24:55 (min:s). the subjects’ personal best times for the 10, 21 and 42 km were 40:31 ± 4:21; 89:42 ± 10:6 and 190:27 ± 33:43 min:s respectively. therefore, dur­ ing the 10, 21, and 42 km races in this study the sub­ jects ran 7, 3 and 10% slower than their personal best times for the same distances. the average hrs mea­ sured during all three races, and the average hrs pre­ dicted at the same running speeds on the basis o f measurements taken during the indoor testing, are shown in table ii. table i i . average measured and predicted hrs for the subjects in the 10, 21 and 42 km races (values expressed as mean ± sd) variables 10km 2 1 k m 4 2 km ( n = 6 ) (at = 6 ) ( n = 5) average m easu red h r (b e a ts/m in ) 16 3 ± 13 1 66 ± 10 156 ± 6 p redicted h r (bea ts/m iii) 1 4 3 ± 22* 151 ± 13* 137 ± 17* 11r:; | {1 leal s in in) 20 ± 7 15 ± 7 19 ± 13 % h r,llix 90 ± 5 9 3 ± 4 8 6 ± 4 % ptrs 74 ± 5 * 75 ± 4 * 6 4 ± 7 * p < 0 .0 3 p r e d ic te d h r v . average m easu red h r in 10, 21, ’ p < 0 .0 1 %ptrs 10 k in v. % ptrs 4 2 kin. ' p < 0 .0 5 %ftrs si k in v. %ptrs 42 km . ptrs p ea k trea d m ill running sp eed . and 4 2 km raees. the hrs measured and predicted for each subject in the 10, 21 and 42 km races are shown in figs 1, 2 and 3 respectively. the hrs measured during the races 150 100 5 0 0 200 150 (1 ) (2 ) t v ^ 'sv ^ s' s y a >v. ............................... (3) 7 14 21 28 3 5 42 km (4) (5), 7 14 21 2 8 3 5 42 km f ig. 1. h e a r ts r a te s o f th e s u b je c ts ( n = 6 ) m e a su red d uring th e 1 0 km r a c e a r e sh o w n a s 0 . e a c h s u b je c t ’s h e a r t r a te p r e ­ d ic te d fr o m th e s a m e ru nn in g s p e e d in n o n -co m p etitiv e con di to n s is s h o w n as o • f ig. 2 . h e a r t s r a te s o f th e s u b je c ts ( n = 6 ) m e a su red d uring th e 2 1 km r a c e a r e sh o w n as # . e a c h s u b je c t ’s h e a r t r a te p r e ­ d ic te d fr o m th e s a m e ru n n in g s p e e d in n o n -co m p etitiv e con d i to n s is sh o w n a s o ■ f ig. 3. h e a r ts r a te s o f th e s u b je c ts ( n = 6 ) m e a su red d uring th e 4 2 km r a c e a r e sh o w n a s 0 . e a c h s u b je c t's h e a r t r a te p r e ­ d ic te d fr o m th e s a m e ru n n in g s p e e d in n o n -co m p etitiv e con di to n s is sh o w n a s (j • were consistently higher than the hrs predicted from the running speeds during the races in all the subjects (p < 0.03).' the fatigue scores, according to the rose/noakes scale, after the races and track test are shown in table iii. there was no difference in these fatigue scores measured after the track test or after each race. the 8 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) discussion table iii. fatigue scores according to the rose/n oakes scale after the track test and each race (values expressed as mean ± sd) variables race track test 10 k m (n = 6) 6 .2 ± 1.7 7 .2 ± 1.7 21 km (n = 6) 6 .8 ± 2.5 6 .7 ± 2.5 4 2 km gv = 5) 7.0 + 1.7 6 .0 ± 2.5 level o f fatigue after each race, as measured by this questionnaire, did not explain iir li(r (r = 0.01, p = 0.96). the magnitude o f iiruir was not explained by the subjects’ v 0 2max (r = 0.44, p = 0.08), perception o f fatigue after the race (r = -0 .0 2 , p = 0.93), running speed during the race (r = 0.17, p = 0.51), or running s intensity' (%mr,ii1lx) during the race (r = -0 .0 1 , p = 0.97). the graph o f racing speed versus %hrillax and racing speed versus tlrtlin are shown in fig. 4. there were weak relationships between the laborat ory measures o f peak treadmill running speed (ptrs) and hr|lfr (r = 0.51 and p = 0.04), and h r nax achieved during the treadmill test and h r ^ (r = 0.64, p = 0.006). 100 95 x co (z 90 i 85 80 0 0 30 r 25 jc e 20 ; w *30) q 15 : ~o cl 10 ri • 10 km o 21 km a 42 km 200 250 racing speed (m/min) 300 fig. 4. g ra p h s o f ra cin g s p e e d (m / m in ) v. %>i1 r,„,lr a n d i i k diir (b e a ts / m in ) d uring 1 0 ( n = 6 ) , 2 1 ( n = 6 ) a n d 4 2 km ( n = 5 ) ra ces. the major finding o f this study was that h r measured during races o f varying distances was consistently higher than the h r elicited at similar running speeds in non-competitive situations. this finding supports an earlier study done in this laboratory.14 the mechanism for the hr(hfr is not known and cannot b e ascribed to the perception o f effort as the fatigue scores were sim­ ilar after the non-competitive field test and after the races. the next important finding was that the running intensity, as predicted as a %hrmax, was not different between the 10, 21 and 42 km races (table ii) although there was a significant difference in the sub­ jects’ running speed (expressed as a percentage o f ptrs) (table ii). this suggests that under competitive racing conditions the h r expressed as a percentage o f h r na.x, is not an accurate marker o f exercise intensity. this is in contrast to a non-competitive situation where hr as a measure o f exercise intensity accurately reflects increases in running speed (r = 0.98). it should b e noted that the subjects ran 3 10% below their best times for the various race distances in this study. it is therefore tempting to conclude that the results could even underestimate the real extent o f itr,ii(t in elite athletes. had the subjects been racing with the intention o f trying to better their personal best times, then it is possible that the hr,]nr could have been greater. the regulation o f h r during exercise is complex913 and it is beyond the scope o f this study to explain the mechanism causing iir(lin. it can, however, be con­ cluded that the hrs during competition are higher than the hrs at the same running speed in non-com petitive situations. in addition, this h r liff cannot be accounted for by the subjects’ perception o f fatigue measured after the race or running speed or running intensity during the race (fig. 4). although there were weak relationships between the laboratory measures o f ptrs and iir(un (r = 0.51) and hr,llax achieved during the treadmill test and hr,nn (r = 0.64), these relation­ ships lacked the power needed to predict accurately hr|ifr from laboratory measurements conducted before the race. in summary, h r measured during competitive exer­ cise is not an accurate measure o f exercise intensity'. the study was supported by polar electro oy, kempele, finland, the medical research council of south africa and the nellie atkinson and harry crossley research funds of the university of cape town. r e f e r e n c e s 1. arts fjp, kuipers h. the relation between power output, oxygen uptake and heart rate in male athletes. int j sports med 1994; 15: 228-31. 2. claremont ad, nagel f, reddan wd, brooks ga. comparison of metabolic, temperature, heart rate and ventilatory responses to exercise at extreme ambient temperature (0 and 35°c). med sci sporls exerc 1975; 7: 150-4. continued on p a g e 1 9 sports medicine july 1999 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research article improved time-trial performance after tapering in well-trained cyclists a bosch’ (bsc, ma, phd) a thomas2 (ba, bsc (med)(hons) sports science) td noakes8 (mb chb, md, facsm) 'l ib e r ty l ife c h a ir o f e x e r c is e a n d s p o r ts s c ie n c e a n d m r c /u c t b io e n e r g e tic s o f e x e r c is e r e s e a r c h u nit, d e p a r tm e n t o f p h y siolog y , u n iv e rs ity o f c a p e t ow n m e d ic a l s c h o o l “ 3m r c /u c t b io e n e r g e tic s o f e x e r c is e r e s e a r c h u n it, d e p a r tm e n t o f p h y siolog y , u n iv e rs ity o f c a p e tow n m e d ic a l s c h o o l abstract objective. the purpose o f this study was to deter­ mine whether cycling performance improved dur­ ing a 14-day taper, the tim e course o f any improvement, and the possible physiological rea­ sons for any change in performance. design. twenty trained male cyclists (> 250 km /wk) were randomly assigned either to a control group that continued training as usual, or to a reduced-training (tapering) group. groups were further randomly subdivided and then pair m atched into a time-trial group (5 controls and 5 experimental subjects) who completed four 20 km time-trials on days 0, 4, 8 and 14 o f the tapering programme, or a laboratory test group that per­ formed a variety o f laboratory tests instead o f the time-trials. on the same days the remaining sub­ jects participated in ’ a laboratory-based trial in which maximum oxygen consumption, peak power output (ppo) and peak post-exercise blood lactate concentrations, anaerobic power and resting mus­ cle glycogen concentrations were measured. setting. trials were conducted in an exercise labo­ ratory and at a cycling track. interventions. experimental subjects reduced their training frequency to 66% and their weekly training duration to 60% o f normal. training intensity in both experimental and control groups was main­ tained. main outcome measure(s). performance would be improved after tapering in both time trial and labcorrespondence: professor td noakes mrc/uct bioenergetics o f exercise research unit sports science institute o f south africa boundary .road newlands 7700 tel: 021 686 7330 fax: 021 686 7530 e-mail: tdnoakes@sports.uct.ac.za oratory subjects, with the physiological parameters measured in the latter group providing a physio­ logical explanation for the improved performance. results. time-trial performance became slower in the control subjects from day 0 (28.3 ± 0.3 min) to day 14 (29.3 ± 0.2 min), but became significantly faster (p < 0.05) in the reduced training (taper) group from day 0 to day 8 (29.5 28.7 ± 0.8 min) and from day 8 to day 14 (28.7 28.5 min). similarly, ppo increased significantly with reduced training from day 0 (382 ± 32 watts (w)) to day 14 (404 ± 34 w; p < 0.05), but did not change in the control group. no other measured physiological variable changed significantly. conclusions. similar to previous reports, these data demonstrate that a 14-day period o f reduced train­ ing can improve exercise performance, both in field tests and in laboratory tests, in cyclists who habit­ ually train 250 km or more per week. eight to 14' days o f reduced training were required for time trial performance to be optimal. however, the mechanism for this effect was not identified by the measured physiological variables. introductioii athletes frequently reduce their training load imm edi­ ately before major competition or after a competitive season in order to allow recovery from the fatigue asso­ ciated with racing and heavy daily training.710 recent findings show that a number o f physiological and performance adaptations can be maintained even when training volume and frequency are reduced,91013 provided that the usual exercise intensity is main­ tained.9 however, many athletes fear that any reduc­ tion in training volume for more than a few days will inevitably lead to a dramatic fall in fitness and impaired racing performance. studies o f reduced training have been done on run­ ners,1011 swimmers*0 and cyclists.14 the aim o f the pre­ sent study was to determine the effect o f a period o f reduced training on the exercise performance o f cyclists using both a field and laboratory test to evalu­ ate performance changes and provide possible physio­ 10 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:tdnoakes@sports.uct.ac.za logical mechanisms that might explain the findings. these tests included measures o f neuromuscular mechanisms in addition to conventional measures o f aerobic and oxygen independent ‘ fitness’ . it was hypothesised that whatever mechanisms may be responsible for improvement in performance after tapering would apply equally whether the cyclist was endeavouring to improve performance in the laboratory or on the track. materials and methods twenty well-trained male cyclists volunteered to par­ ticipate in this study, which was approved by the research and ethics committee o f the faculty of medicine o f the university o f cape town medical school. all signed informed consent and were free to withdraw from the trial at any time. entrance to the study was limited to cyclists who had consistently trained more than 250 km /w k throughout the year for at least the last year. this included racing and inter­ val training. before the study subjects were asked to record a 2-week training schedule in order to deter­ mine their training volumes, frequencies and intensi­ ties. typically, training consisted o f one training session o f approximately 100 km on the weekend, with five other training sessions o f approximately 60-minute duration during the week. most training was done at moderate intensity (based on subject heart rate and rating o f perceived exertion), with approximately one ride per week o f high intensity. subjects were randomly assigned to control and experimental groups. control subjects continued their usual training programme, whereas the experimental subjects followed a 14-day taper regimen during which training frequency was reduced to 66% and training duration to 60% o f their normal training schedules. however previously documented training intensity was maintained throughout the study. training was reduced in a single step rather than a graded reduc­ tion. whereas it has been suggested that a graded reduction m aybe advantageous over a step reduction,12 this applies to swimmers, not runners. runners may need a greater reduction in training than is suggested in the studies cited by houmard and johns.12 the con­ trol and experimental (reduced-training) groups were then further subdivided into laboratory and field groups, and then pair-matched. on the day before a test each subject performed a training session stan­ dardised according to previous training documented in his training log book. after familiarisation with the procedures, cyclists in the two field groups performed four 20 km time-trials on an outdoor cycle track on days 0, 4, 8 and 14 o f the study. time-trials were conducted individually to pre­ vent drafting. the control subjects were used to control for the influence o f environmental factors, especially differences in wind speed and temperature. matched subjects from both the control and experimental groups performed the time-trial on the same day and at the same time o f day to avoid any diurnal variation in performance measures, on the subject’s own bike, and wearing the same type o f clothing. subjects in the laboratory group were tested on days 0, 4, 8 and 14 for a number o f physiological parame­ ters, described subsequently. before the start o f the performance trials all sub­ jects were weighed and their per cent body fat was cal­ culated from biceps, triceps, subscapular and supra-iliac skinfold measurements using a skinfold caliper (holtan ltd., crymych, uk) according to the equations o f dumin and wormersly6 as described by brozek et al." subjects in the laboratory trial reported to the labo­ ratory on days 0, 4, 8 and 14 for the performance o f a wingate anaerobic test (wt) on a mechanically-braked monark 818 cycle ergometer (varberg, sweden) that was calibrated by means o f a weighted torque balance attached to the crank. the ergometer was modified with toe straps, adjustable racing handlebars and sad­ dle, and interfaced with an apple he microcomputer. the same seat height was used for each individual dur­ ing each test. sample periods o f 0.5 seconds enabled calculation o f peak power (wt-pp), taken as the high­ est average power for any 5-second period during the test and the mean power (mp) that was sustained throughout the test. after a 5-minute warm up at a load and speed select­ ed by the cyclist, subjects began pedalling at minimal resistance and gradually increased the cadence to 115 120 rev/min. when this cadence was attained, the full load (0.075 kp/kg body weight) was applied by an investigator and the computer programme was activat­ ed.7 subjects were instructed to remain seated and were verbally encouraged to maintain maximal pedal rates throughout the test, i.e. to perform ‘all out’ from the start. blood lactate concentrations were deter­ mined spectrophotometrically from venous blood (1 ml samples) drawn immediately on completion o f the wingate test and then at 1-minute intervals for 5 min­ utes via a cannula placed in an antecubital forearm vein before testing commenced. after a 10-minute rest period, testing was conducted for determination o f maximum isometric tension, max­ imum speed o f contraction (vmax) and total work done on the same monark bicycle ergometer as for the wingate test. from rest, with the pedal 10° above the horizontal, a countdown o f 3 seconds was given to the subject who subsequently pedalled as quickly as possi­ ble for 5 seconds at randomly chosen resistance set­ tings o f 3 kp (29.4 n), 5 kp (49 n), 2 kp (19.6 n), 7 kp (6 8 .6 .n), 4 kp (39.2 n) and 6 kp (58.8 n).15 rest periods o f at least 2 minutes were allowed between each exercise bout. the theoretical power output at zero load (po) was calculated from the zero point o f the graph o f power output versus resistance, vmax from a graph o f velocity versus resistance and total work done from the area under the power/resistance graph. after another 30-minute rest period, subjects per­ formed maximal progressive exercise to exhaustion on an electrom echanically braked cycle ergometer sports medicine july 1999 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) (excalibur, lode, groningen, the netherlands). for measurement o f peak power output (ppo) and maximum oxygen consum ption (v 0 2max), air was inspired from a hans rudolph 2 700 one-way valve (hans rudolph inc., kansas city, kansas, usa) con­ nected to a mijnhardt dry gas meter. a nose clip pre­ vented nasal breathing. expired air was passed through a 15 1 baffled mixing chamber from which con­ tinuous sampling occurred by ametek n-22m oxygen and cd-3a carbon dioxide gas analysers (thermox instruments, pittsburgh,. pa). before each test, the gas meter was calibrated with a hans rudolph 3 1 s y r i n g e and the analysers were calibrated with air and a 4% co.,: 1 6 % 02:80% n2 mixture. the cumulative value for each minute o f the test for ventilation (vi), oxygen con­ sumption (vos), carbon dioxide production (vc02), and respiratory exchange ratio (rer) were printed "out at the end o f the test using standard formulae for calcu­ lations. subjects first pedalled at a workload o f 3.33 watts (w )/kg for 6 minutes, during which time submaximal v 0 2 was measured. blood was drawn from a forearm vein through a stopcock for subsequent measurement o f blood lactate concentrations. ratings o f perceived exertion (rpl) were recorded at regular intervals dur­ ing the exercise bout using the 1 10 point borg scale. heart rate was recorded on a lohmeier m607 monitor (munich, west germany). on completion o f the sub maximal test, the workload was increased by 50 w for 150 seconds. thereafter the workload was increased by 25 w every 150 seconds until the subject voluntari­ ly terminated the test. venous blood was again drawn immediately via the indwelling cannula on completion o f the test and then at 1-minute intervals for 5 minutes for subsequent determination o f blood lactate concen­ trations. peak workload was calculated using the formula: peak workload (w) = final workload (w) +(t/150 x 25),7 where t is time in seconds o f the final workload com ­ pleted. this battery o f tests could lead to fatigue, with one test possibly affecting a subsequent test. however, this was consistent each time that testing was done and would affect all subjects. post-exercise muscle samples were obtained at the end o f the trial from the right vastus lateralis o f each cyclist, using the needle-biopsy technique as described by bergstrom.1 the sample was immediately frozen in liquid nitrogen and stored at -8 0 °c for subsequent determination o f muscle glycogen content according to the method o f lowry and passonneau.13 statistical analyses statistical significances o f changes over time and between groups were assessed by means o f a two-way analysis o f variance (anova) for repeated measures. when a significant f-ratio (p < 0.05) was found, a scheffe test was used for p ost hoc analysis. where necessary, between-group differences were measured with a student’s unpaired m.est. a value o f p < 0.05 was regarded as significant. table i. physical characteristics before a reduced training protocol laboratory groups field groups r educedr educedtraining c ontrol training c ontrol group group grou p group a ge (yrs) 22.6 21.2 26.0 21.3 ± 2.6 ± 1.2 ± 2.9 ± 0 .4 m ass ckg) 75.2 74.7 73.9 71.2 ± 5 . 4 ± 4 . 3 ± 2 . 3 ' ± 2.7 b ody fat con ten t % 9.9 10.5 11.6 10.8 ± 0 . 8 ± 0 . 8 ± 1.1 ± 1.0 peak pow er output (w ) 382.8 37 4 .6 _ _ ± 32.3 • ± 19.1 m axim um oxygen consum ption (l/m in ) 4.5 4.7 . _ ± 0 . 2 ± 0 . 2 values are m eans ± s d ( x = 5 in each sub-group). results subjects’ physical characteristics are shown in table i. subjects in the laboratory group had high v 02nlax values (4.6 ± 0.2 l/min; mean ± sd) and reached high ppo (394 ± 27 w). subjects in the time-trial group did not do v 0 2max or ppo tests as the only point o f interest was whether their time-trial performance improved or not. there were no significant differences in age, mass or per cent body fat between the laboratory and field groups or in v 0 2max and ppo in the control and reduced-training subjects in the laboratory group. changes in 20 km time-trial performance in the field group are shown in fig. 1. performance for both control and reduced-training (taper) groups were con­ stant for days 0 and 4 o f the trial. thereafter perfor­ mance in the control group was significantly impaired on days 8 and 14, whereas performance in the reduced training group improved significantly by day 14. similarly, ppo measured during the v 0 2max test (voa-ppo) increased steadily in the reduced training 30 25 □ control d reduced training i i i j 14 time (days) f ig. i. t w en ty km tim e-tria l p e r fo r m a n c e (m i n ) in c y c lis ts in co n tr o l a n d red u ce d -tra in in g g r o u p s on d a y s 0, 4. 8, a n d 1 4 . t im e-trial p e r fo r m a n c e im p r o v e d s ig n ifica n tly in th e red u ced tra in in g g r o u p on d a y 1 4 b u t w a s im p a ired on d a y s 8 a n d 1 4 in th e c o n tr o l g r o u p . v alues a r e m e a n s ± s d . * s ig n ifica n t ( p < 0 . 0 5 ) im p r o v e m e n t fro m d a y 0. 12 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) q control □ reduced training 450 l t i 350 : 0 | 300 1 co<d cl 0 4 8 14 time (days) fiq. 2 . p e a k p o w e r o u tp u t ( p p o ) ( w ) in c y c lis ts in co n tr o l a n d red u ced -tra in in g g r o u p s o n d a y s 0, 4 , 8 a n d 1 4 . p p o w a s u n c h a n g ed in th e c o n tr o l g r o u p b u t in c r e a s e d sig n ifica n t­ ly o n d a y 1 4 in th e r e d u c e d tra in in g g r o u p . v a lu es a r e m e a n s ± s d . *s ig n ifica n t im p r o v e m e n t from d a y 0. group in the laboratory study (fig. 2). peak power out­ put was significantly higher in the reduced training group on day 14 than on day 0 (fig2). in contrast, v 0 2-pp0 was unchanged in the control group. per cent changes in vog-ppo and time-trial perfor­ mance in the diflerent groups are listed in table ii. time-trial performance improved by 2.8 ± 3.9% in the reduced-training field group but fell by 3.5 ± 4.8% in the respective control group. as a result, the perfor­ mance difference between the groups changed by 6.3%. v 0 2max, blood lactate concentration at v 0 2max, mus­ cle glycogen content and submaximal oxygen consump­ tion, heart rate, blood lactate concentrations and ratings o f perceived exertion were not different between reduced training and control subjects in the laboratory group on any o f the test days (table iii). i nor were there inter-group differences in peak power, table el per cent change in ppo and in time-trial performance in control and reduced-training groups from the start o f tapering (day 0) to days 4, 8, and 14 o f the reduced training period r e d u ce d training c on trol tim e-trial tim e-trial ppo p erform ance pp o perform ance days 0 4 3.6 0.5 4.5 1.4 ± 10.2 ± 5.0 ± 8 . 4 ± 3 . 4 days 0 8 3.3 2.0* ' 1 .4 3 . 1 ± 11.7 ± 2 . 9 ± 11.4 ± 7 . 3 days 0 14 5.6* 2.8* 1 .2 3 . 5 * ± 9.2 ± 3 .9 ± 8 . 5 ± 4.8 * significantly d ifleren t from the p e r cent ch an ge b e tw e e n day 0 and day 4 (p < 0.0 5 ). values ore m eans ± sd , n = 5 in ea ch sub-group. a p ositive value in d ica tes an im p rov ed p erform an ce, a negative value in d ica te s . a red u ction in perform an ce. mean power, fatigue index or blood lactate concentra­ tions measured after the wingate test (table iv) or in maximum isometric tension, maximum speed o f con­ traction, or total work (table v). table iiicardiorespiratory and metabolic mea­ sures in the reduced training and control groups in the laboratory trial days 0 4 8 14 m axim um oxygen r t 4 .5 4 .5 4 .5 4 .6 consum ption + 0.2 ' ± 0 . 2 ± 0.3 ± 0.2 (1/m in) ct 4 .7 4.6 4.2 4 .3 ± 0.2 ± 0.2 ± 0 . 1 ± 0.2 m u scle glycogen r t 82.6 7 9 .5 9 5 .9 8 3.7 concentrations ± 7 . 8 ± 3.2 ± 13.5 ± 13.2 (m m o l/k g w et ct 101.57 5 .3 87.5 100.6 w eight) ± 16.9 ± 6 .0 ± 5 . 6 ± 6 . 2 submaxim al r t 3.3 3.2 3.2 3.2 vos (1/m in) ± 0.2 ± 0.2 ± 0.2 ± 0.2 ct 3 .3 3.3 3.4 3.3 ± 0 .3 ± 0.1 ± 0.2 ± 0.2 subm axim al rt 16 8 .4 . 161.2 164.2 162.2 h e a rt rate ± 10.4 ± 8.2 + 10.8 ± 10.1 (b e a ts/m in ) ct 166.41 15 6 .4 1 60.8 157.4 ± 1.4 ± 4 . 7 ± 3.2 ± 4 .7 submaxim al r t 4.1 3.7 3 .7 3.3 b lo o d lactate ± 0 .7 ± 0 .7 ± 0.6 ± 0.6 concentrations ct 4 .4 3.4 3.1 3 .5 (m m ol) ± 0 .5 ± 0 .7 ± 0 . 9 ± 1.1 subm axim al r t 1.5 1.3 1.5 1.0 ratings o f ± 0 .4 ± 0 . 3 ± 0 . 4 ± 0 . 2 perceived ct 1 .9 1.9 1.0 1.4 exertion ± 0.7 ± 0.6 ± 0 .7 ± 0.5 (units) values are m ea n s ± sd ; a7 = 5 in ea ch group. r t = re d u ce d training group; c t = control group. table iv. skeletal muscle power output during the wingate test and peak blood lactate concentrations in reduced training and control groups in the laboratory trial days 0 4 8 14 peak r t 1 01 4 .0 1 0 8 4 .4 1 102.4 1 06 0 .8 pow er (watts) ± 2 7 .6 ± 3 6 .1 ± 3 2 .3 + 6 0 .5 ct 1 02 4 .5 1 131.0 1 140.0 1 04 6 .3 ± 20.9 ± 5 6 .8 ± 37.9 ± 4 1 .6 mean r t 7 0 8 .5 6 9 8 .0 735.5 7 2 7 .9 pow er (watts) ± 4 4 .8 ± 28.8 ± 2 7 .9 + 32.4 ct 7 3 6 .0 7 1 8 .7 72 3 .0 6 9 8 .9 ± 4 4 .5 ± 31.0 ± 3 8 .3 ± 30.2 b lo o d r t 10.5 1 3.8 12.7. 13.7 lactate ± 2.0 ± 1.8 ± 1.5 ± 1.2 concentrations ct 10.2 10.7 10.3 10.9 (m m ol/1) ± 1.2 ± 1.4 ± 1.1 + 1.0 values are m eans ± s d ; n = 5 in e a ch group. r t = r e d u c e d train ing group; c t = co n trol group. sports medicine july 1999 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table v. measures o f skeletal muscle contractile function in reduced-training and control groups in the laboratory trial days 0 4 8 1 4 p o (watts) r t 172 18 6 161 176 ± 10 ± 1 0 ± 9 ± 16 ct 168 18 4 170 136 ± 3 ± 22 ± 5 ± 3 2 v m« (m /s ) r t 16.0 16.0 17.0 16.0 ± 0.6 ± 0.5 ± 1.3 ± 0 . 5 ct 16.7 1 6 .8 16.7 13.5 ± 0 . 6 ± 0 .4 ± 0 . 5 ± 3.0 values are m ea n s ± sd ; n 5 in e a c h group. r t = r e d u c e d training group; c t = con trol group. discussion the important finding o f this study was that cycling performance in a field time-trial improved significant­ ly by 2.8% in a reduced-training group over the 14 days o f the study, whereas performance becam e significant­ ly (3.5%) slower in a control group that continued their usual training during the same period (fig. 1). this decline in performance is difficult to explain, but may have been due to boredom o f the subjects with the test­ ing regimen as it also occurred in the laboratory control group, whereas the experimental groups may have remained motivated since they seemed to know intu­ itively that they had performed better or worse than in their previous test. alternatively the longer period o f normal training load may have resulted in fatigue in the control subjects. ppo (table ii) but not vogmax (table iii) also increased by 5.6% in the experimental group during this period, but was unchanged in the control group (fig. 2). surprisingly, there were no other changes that might explain the superior time-trial performance or the increased v 02-pp0 o f the reduced training sub­ jects. muscle glycogen content, measures o f submaxi mal performance including heart rate, voa, blood lactate concentrations and ratings o f perceived exertion were not different between reduced training and con­ trol groups in the laboratory trial, nor did they change during the duration o f the experimental period. similar results were found for measures o f explosive muscle function measured with either the wingate test or the isometric muscle function testing. the improved time-trial performance after a period o f reduced training in the well-trained cyclists in hi is study could not be explained by changes in physiologi­ cal variables measured during submaximal cycling or in short duration tests o f skeletal muscle function. previously, shepley et al.m have shown increased cit­ rate synthase activity, increased blood volume and an increase in muscle strength after a period o f reduced training during which intensity was kept high. changes in ppo were in the same direction as those o f the time-trial performance (table ii). in a study by costill et al.s improvements in perfor­ mance in swimmers after reduced training were attri­ buted to gains in muscular power. in the present study, improvements in both time-trial performance and ppo (muscular power) were found, but the underlying physiological determinant o f this change was not eluci­ dated. a similar conclusion was reached by martin et al. |jl who studied changes in cycling performance and isokinetic skeletal muscle function in a group o f colle­ giate cyclists during 6 weeks o f high-intensity aerobic interval training, followed by a 2-week taper in which training intensity and volume were reduced substan­ tially. both interval training and the taper produced increases in cycling performance (15% and 8%, respec­ tively) and in isokinetic skeletal muscle function; but the time course o f the changes was different. in par­ ticular, cycling performance was greatest after the first week o f the taper, whereas isokinetic skeletal muscle function continued to increase throughout the 2-week taper. martin et al.1* concluded that these findings were consistent with data which show that gains in muscle strength are not tightly linked to changes in performance with reduced training, and hence are not the sole determinant o f changes in performance follow­ ing a period o f tapering or reduced training. the lack o f a significant change in v 0 2max alter 2 weeks o f reduced training in the current study, despite increases in both ppo and performance, is surprising since an increase in ppo (presumably as a result o f a period o f recovery from hard training) is often accom­ panied by an increase in v 0 2tllax, because more work can be performed. however, an unchanged v 0 2tllax after a reduction in training has also been shown in the stud­ ies o f bryntesson and sinning3 and hickson and rosenkoetter.8 in both studies v 0 2max values were unchanged during 15 weeks’ training at 33% o f the nor­ mal training volume. these results and those o f the present study confirm the finding that v 0 2max can be maintained despite a large decrease in training load. since no significant differences were found in any o f ' the physiological variables measured in this study, including voa, rpe, heart rate during submaximal exercise, resting muscle glycogen, post-exercise blood lactate concentrations, or in measures o f in vivo skele­ tal muscle function, it would seem that these variables are not important in mediating performance changes with reduced training. alternatively, current methods are not sufficiently sensitive to identify small changes that produce measurable changes in cycling perfor­ mance. in conclusion, this study shows that the perfor­ mance o f endurance-trained cyclists, like that o f swim­ mers45 and runners,1011 improves after a short period when training volume is reduced by 40% and training frequency by 34% while training intensity is main­ tained. references on p a g e 2 2 14 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research article heart rate response of young cricket fast bowlers while bowling a six-over spell ra stretch1 (dfhil) mi lambert2 (phd) 's n o r t b u reau, u n iv ersity o f p o r t e liz a b e th 2m r c /u c t b io e n e r g e tic s o f e x e r c is e r e s e a r c h u n it, s p o r ts s c ie n c e in stitu te o f s o u th a frica , c a p e tow n abstract objective. to determine whether fatigue, mea­ sured as a percentage o f maximum heart rate (% hrmax), occurred during a six-over bowling spell in fast bowlers. design. twenty-one young elite or potentially elite fast bowlers (junior group n = 11; senior group n = 10) were recruited for the study. the bowler’s heart rate was recorded during a six-over bowling spell in a turf cricket net. the accuracy o f each delivery was recorded, and various anthropometric and flexibil­ ity data relevant to the physical demands o f bow l­ ing were also collected. results. the junior (11.6 13.3 years) and senior (17.7 21.5 years) groups had similar run-up lengths o f 15.9 ± 2.0 m and 15.2 ± 2.8 m, respec­ tively. there were no differences between the groups for active and rest time during each over. no changes in the active/rest ratio occurred during the course o f the experiment in either group. the average exercise intensity during the six-over spell was the same for juniors (77 ± 5% and seniors (77 ± 4% hr,,,.,,). there were no differences between the dominant and non-dominant arm girths in the juniors, in contrast to the senior group who had a significantly greater dominant arm girth compared with their non-dominant arm girth (p < 0.0003). conclusion. there was no evidence in this study to limit the number o f balls bowled by young fast bowlers to 36 or less, at least based on exercise intensity during bowling. future studies need to address biomechanical factors during bowling that may predispose the bowlers to in jury. correspondence: dr richard stretch sport bureau university o f port elizabeth po box 1600 port elizabeth 6000 tel: 041 504 2584 . fax: 041 532 605 introduction cricket is a sport that has a ‘m oderate’ injury risk.21 numerous studies indicate that the incidence o f injuries in cricket players is increasing rapidly.2-4-7 in part, the physical demands on cricketers would seem to be increasing. this is because in addition to technical skill, the m odem cricketer must possess a high level o f fitness, making him susceptible to injuries caused by repetitive training. forty-six per cent and 47% o f the schoolboy injuries occurred during matches and practices respectively, and occurred fairly regularly throughout the season, with a slight increase during the early and latter part o f the season.20 the other injuries (7%) occurred during other nonspecific exercise training. it is known that over-use injuries are more common towards the end o f the season.2 of particular relevance is the finding that many more ‘adult-type’ injuries are occurring in young cricketers, with bowling being the major cause o f these injuries. forty-seven per cent o f the injuries sustained by young cricketers occurred to fast bowlers.20 this was greater than in club and provincial cricket (42%).19 injuries were predominantly to the lower back and included muscle tears, especially o f the hip flexors, adductor longus and rectus femoris muscles. studies have also shown that the lower backs o f fast bowlers are particularly prone to injury, with the common injuries being stress fractures to the third, fourth and fifth lumbar vertebrae (11% in young australian fast bowlers8), spondylosis (50% in australian fast bowlers16), pedicle sclerosis, disc degeneration and bulging (21% o f western australian players assessed4). damage to the epiphyses around the knee, traction apophysis, and compressive stress to the articular car­ tilage o f the femur and talus were also common in young australian fast bowlers. thirty-eight per cent o f the bowlers suffered one disabling injury during a sin­ gle season, with stress fractures o f the lumbar and/or sacral vertebrae (11%), and soft-tissue injuries to the back (27%) causing them to miss at least one match.7 the high incidence o f back injuries in young fast bowlers is not the result o f a single aetiological factor, but rather a combination o f factors that may predispose these players to injuries. these factors included inher­ ent physical and physiological factors such as postural defects, high physical demands, specific biomechanical demands o f different bowling techniques, an escalation in training frequency and the duration o f bowling spells sports medicine july 1999 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) in both practices and matches.1' 84' 5'71011 ''*■ 20 in order to address the problem o f over-use injuries in fast bowlers, guidelines were drawn up for use in australian cricket in 1989.5 in match play these guide­ lines varied from a limit o f two spells o f 4 or 6 overs for under-12 and under-16 bowlers respectively, to three spells o f 6 or 8 overs for under-19 and senior bowlers respectively. according to the guidelines each spell was to b e followed by a 1-hour break for all age groups. in addition, guidelines were developed for the quanti­ ty and quality o f bowling to b e carried out in practices. other countries, including south africa, have either accepted these guidelines with or without modifica­ tions, without necessarily legislating that these guide­ lines b e enforced. but these guidelines have not been evaluated under m o d e m playing conditions. furthermore, little performance analysis has been done on cricketers. consequently the energetics o f fast bowling in cricket is not well understood and as a result players and coaches base their training and coaching on beliefs, hunches, trial and error, and the practice o f successful players. studies on the energy demands o f cricket players have shown that bowling in the nets and in a match have an energy cost o f 33.5 k j/m in and 22.0 k j/m in , respectively.6 the values for batting and fielding were found to b e even lower than those for bowling in a match. the estimated gross energy cost o f bowling in a test match was 8.85 k j / m 2/m in ,6 while the energy expenditure o f young slow bowlers was 7.5 kj/m in.15 the reason for these values being much lower than the values for the bowlers in the study by fletcher6 is p os­ sibly because they were based on a number o f assump­ tions with regard to run-up length. it is evident that the incidence o f cricket injuries, particularly over-use injuries in young fast bowlers, is a growing problem that will continue to escalate unless preventive steps are introduced. data are lacking on the physical demands o f bowling. the present study was conducted to determine the exercise intensity, based on heart rate, o f young elite cricket fast to m edi­ um-fast bowlers, with the aim o f determining whether there is cumulative fatigue measured as heart rate drift during a 6-over bowling spell. these data will contribute to the establishment o f recommendations on the maximum number o f consecutive overs a young fast bowler should b e allowed to bowl. together with providing a greater understanding o f the physical demands o f fast bowling, this study will provide coach es and fast bowlers with a better rationale for their training programmes. methods twenty-one young elite or potentially elite fast bowlers who were invited to participate in specialised training by the eastern province cricket board were selected for the study. these bowlers were divided into a junior group (n = 11), with the bowlers all under 14 years o f age, and a senior group gy = 10), with the players all aged between 17 and 22 years o f age. the following anthropometric data were collected according to the descriptions o f ross and marfell jones:17 mass (kg), stature (cm), biceps, triceps, sub­ scapular, supra-iliac, abdominal, front thigh and medial calf skinfolds (mm) and right and left relaxed arm girth (cm). body fat content was estimated as the sum o f the seven skinfold measurements. the follow­ ing tests were used to measure the flexibility o f the subjects:13 1. shoulder and wrist flexibility were assessed with the subject assuming a face-down position. the subject held a ruler with the arms straight and shoulder-width apart. the subject raised the ruler horizontally as high as possible while keeping his chin on the floor and elbows straight. the tester measured with a metre stick to the top centre level o f the ruler. the tester used the metre stick to measure the subject’s arm length from the acromial process to the tip o f the m id­ dle finger. the best o f three lifts was subtracted from the arm length to derive the score. the closer the arm lift gets to arm length, the better the score. 2. back and hamstring flexibility were tested using the modified sit-and-reach test. the subjects removed their shoes and sat with their knees fully extended and feet shoulder width apart, placed against a 30 cm box. a ruler was positioned and held so that the ‘zero’ end o f the ruler touched the extended fingers o f the sub­ ject. the subject reached forward, palms down, along the measuring ruler four times and held the maximum reach on the fourth trial for 1 second. the score was recorded as the furthest point reached on the fourth trial. 3. trunk and neck flexibility were assessed with the subject lying face down with his hands at the small o f his back and an assistant holding his hips down. the subject raised upward, extending the trunk and neck as high as possible with the neck in the neutral position, and held the position for 3 seconds. the tester mea­ sured the highest point reached by the tip o f the sub­ je ct’s nose. the distance between the tip o f the nose and the seat o f the subject’s chair was measured to give his trunk and neck length. the best score o f three lifts was subtracted from the trunk and neck length to give the score. the lower the score the better the flexibility. thereafter the subjects were, allowed to warm up before starting the bowling trial. in order to simulate match conditions the bowler had to bowl at a batsman. after each delivery a trained observer gave a rating ( 1 5 ) for the line (the direction o f the ball in relation to the batsman) and length (the proximity o f where the ball bounced in relation to the batsman) o f the delivery. the subjects worked in pairs, with one subject bowling and the other subject simulating fielding during the over. this subject simulated fielding on the boundary by walking in with the bowler for each delivery. a ball was also thrown for him to field and return during the over. after the completion o f an over the subjects swapped position. this continued until both bowlers had each bowled 6 overs. the subject’s heart rate (hr) was recorded continu­ 16 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ously for the 6-over bowling spell in a turf cricket net by means o f short-range telemetry using the polar sport tester (polar electro, finland). the h r monitor was placed on the subject before he commenced his warm-up routine. the recording o f the h r began just before each subject’s 6-over bowling spell. the receivers were programmed to measure and store the h r readings every 5 seconds. the start o f the collection o f the h r data was syn­ c h r o n i s e d with a stop watch in order to relate the hr to specific events during the data collection phase. these included the start and completion o f each over, the start o f the run-up, the completion o f the follow through, when the ball was fielded and any other tasks that the bowler performed. at the end o f the testing session these data were downloaded into a computer using an interface and software purchased from the manufacturers (polar electro, finland). each subject’s exercise intensity was calculated for each over and expressed as the average hr as a per­ centage o f the subjects maximum h r (% hr,,,.^). the subject’s maximum h r was determined in a field test immediately after the bowling experiment. subjects were required to ran 400 m at approximately 80% effort. following a short rest subjects were instructed to run 800 m at maximal effort. the highest h r elicit­ ed during the test was defined' as the maximal hr.12 s tatistical analysis a l l values are expressed as mean and standard devia­ tion (sd). a student’s t-tesl was used to determine differences between the two groups o f fast bowlers. a paired t-tesl was used to determine differences, within a group. an analysis o f variance with repeated mea­ sures was used to determine differences over time. statistical significance was accepted for p values less than 0.05. results the average temperature during the testing period, recorded at the port elizabeth meteorological office, was 22.3°c (ranging from 17.5°c to 22.8 c ) , with a wind speed o f 18 knots (36 k m /h ) blowing across the run-up. the general characteristics o f the subjects are table i. general characteristics of the junior (n = 11) and senior subjects (n = 10) j un ior s en ior variables age (years) mass (leg) stature (cm) sum of 7 skinfolds (m m ) dominant arm girth (cm) __ -r non-dominant arm girth (cm ) 22.0 d om inan t arm v. n on -dom in an t arm p < 0 .0 0 0 3 (seniors). all t h e variables o f th e juniors a re significantly low er th an th ose o f t h e seniors ( p < 0.00 0 0 1 ). m ean sd m ean sd 12.7 0.5 19.0 1.4 4 5 .6 5.2 78.0 10.6 158.3 5 .8 184.9 5.3 57.4 13.2 76.8. 21.6 2 2 .4 1.2 29.3 2 .8 ’ 2 2.0 1.5 2 8 .4 2.8 shown in table i. the ages o f the junior group ranged from 11.6 to 13.3 years and the seniors from 17.7 to 21.5 years. the majority o f the group were right hand­ ed (juniors 8 /1 1 , seniors 9/10). there were no differ­ ences between the dominant and non-dominant arm girths in the juniors. in contrast, the arm girth o f the dominant arm was 0.89 cm ± 0.50 cm greater than the non-dominant arm (p < 0.0003) in the senior group. table ii. flexibility characteristics of the junior ( n = 11) and senior subjects ( n = 10) jun iors s eniors variables m ean sd m ean sd s h ould er and wrist 33.5 11.7 41.1 11.9 flexibility (cm ) b ack and ham string 44.5 4 .5 47.1 10.4 flexibility7 (cm ) trunk and n e ck flexibility 16.2 8 .0 30.6 8 .9 ' (cm ) * s ignificant d ifferen ce (p < 0.0 0 1 ). the flexibility measurements are shown in table ii. the shoulder and wrist, and back and hamstring flexi­ bility were similar between groups. however, the junior subjects were significantly (p < 0.001) more flexible in the trunk and neck flexibility test than the senior sub­ jects (16.8 ± 8.0 v. 30.6 ± 8.9 cm). the length o f the run-up to the bowling crease was similar in each group (15.9 ± 2,0 v. 15.2 ± 2.8 m) (juniors v. seniors). the active and rest time comprising each o f the 6 overs bowled in the study are shown in table iii. there was no difference between groups for active and rest time. furthermore, there were no changes in the active/rest ratio during the course o f the experiment in either group. table hi. the active and rest time (seconds) dur­ ing each of the 6 overs of the junior ( n = 11) and senior (tv = 10) subjects juniors s eniors variables m ean sd mean sd over 1 work (s) 156 31 150 19 r est (s) 2 54 75 246 26 work: rest 0.6 4 0.26 0.61 0.08 over 2 work (s) 143 24 152 20 r est (s) 2 29 47 238 41 work: rest 0.6 4 0.10 0.65 0.10 over 3 w ork (s) 153 46 152 20 r est (s) 2 26 50 25 4 32 work: rest 0.6 8 0.17 0.60 0.10 over 4 work (s) 150 38 152 23 r e st (s) 2 2 0 34 2 26 23 work: rest 0 .6 9 0.19 0.68 0 .1 2 over 5 w ork (s) 146 18 156 21 r e s t (s) 21 9 24 225 22 work: rest 0.67 0.07 0.70 0.13 over 6 w ork (s) 143 21 156 22 sports medicine july 1999 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) minutes f ig . 1 . a ty p ic a l h e a r t r a te r e s p o n s e d u rin g th e 6 -o v er trial. table iv. the average h r (beats/m in) and exer­ cise intensity (%iir,n.„) for each o f the 6 overs for the junior (iv = 11) and senior ov = 10) subjects. junior's seniors variables m ean sd m ean sd over 1 average h r 153 16 149 11 % h r,11;1x 74 8 75 5 over 2 average h r 157 13 152 10 % hrmax 76 6 76 5 over 3 average h r 159 12 153 10 % h r „l;lx 77 5 77 5 over 4 average h r 160 12 155 10 7 8 5 78 4 over 5 average h r 161 12 155 10 79 5 78 4 over 6 average h r 162 11 156 .10 79 5 78 4 average average h r 159 12 153 10 % hrmax 7 7 5 77 4 a typical h r response o f a subject during the 6-over trial is shown in fig. 1. the average h r and exercise intensity (expressed as % ilr,,,. )̂ for each o f the 6 overs is shown in table iv the maximum h r determined in the field test was higher (p < 0.01) for juniors (206 ± 5 beats/m in) than for seniors (199 ± 7 beats/min). however, throughout the 6 overs the average h r and % hr,rlax were similar between groups and did not change as the experiment progressed. the rating score for each o f the 36 deliveries (6 overs) for the junior and senior players are shown in fig. 2. there were no differences between groups or over the course o f the 36 deliveries. discussion the primary finding o f this study was that the exercise intensity o f the junior and senior fast bowlers was sim­ ilar, showing no indication o f cumulative fatigue as the bowling spell progressed. in addition, the accuracy o f each delivery did not change in either group over the 36 balls. therefore, based on exercise intensity and s e n io rs balls f ig . 2. r a tin g s c o r e f o r e a c h o f th e d eliv erie s o f th e 6 o v e r s f o r th e ju n i o r ( n = 1 1 ) a n d s e n io r ( n = 1 0 ) su b jects. accuracy o f each delivery, there is no reason to suggest that there was any acute fatigue affecting bowling per­ formance after 36 deliveries. the dominant arm girth o f the senior players was greater than their non-dominant arm girth, which was in contrast to the junior players who had similar dom ­ inant and non-dominant arm girths. the hypertrophy o f the dominant arm can possibly be attributed to the physical demands o f the bowling action. another study18 on cricket bowlers showed that calf girth mea­ surements were greater in the leg opposite the bowling arm o f each player. this leg is used as an effective lever during the bowling action.18 the hypertrophy o f the bowling arm and the decreased flexibility o f the trunk and neck in the senior players in this study, supported by the findings o f stretch,18 suggests that the bowling action places stresses on the body that result in asym­ metrical adaptations. although it is tempting to con­ clude that these asymmetrical adaptations place the bowler at risk o f injury, this wall have to b e determined in future studies. in summary, there are no grounds (based on the pos­ sibility o f fatigue-induced injury) for restricting the number o f consecutive overs bowled to less than 6. however this study supports the concept o f limiting the number o f overs to 6 as it shows , that there is no associated fatigue. the decreased flexibility o f the 18 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) trunk and neck and the increase in dominant arm girth in the older bowlers suggests that adaptations, possi­ bly as a consequence o f the repetitive loading during the bowling action, take place. whether these adapta­ tions increase the bowler’s risk o f injury remains to be determined. further studies o f bowlers bowling more than 6 overs need to be conducted in order to deter­ mine whether acute fatigue is measurable using the techniques in this study. furthermore, studies need to be conducted to investigate biomechanical aspects o f bowling to determine whether any limits need to be placed on bowling at practices and during matches, with the overall aim o f reducing the risk o f injuries associated with bowling. r e f e r e n c e s 1 clements mr, hamilton dv pneumomediastinum as a complica­ tion o f fast bowling in cricket. postgrad med j 1982; 58: 435. . 2 corrigan ab. cricket injuries. a ust fam physician 1984; 13: 558 62. 3. crisp ta. cricket injuries. sports therapy 1990; 1(1): 22 3. 4 elliott b, hardcastle ph, burnett af, foster dh. the influence o f fast bowling and physical factors on radiologic features in high per­ formance young fast bowlers. sports medicine, training, and rehabilitation 1992; 3: 113 30. 5. elliott b, foster d, blanksby b. send the stumps flying: the science o f fast bowling. perth, australia: university o f western australia press, 1989. 6. fletcher jg. calories and crickct. lancet 1955; 1: 1165-6. 7. foster d, elliott b, ackland t, fitch k. back injuries to fast bowlers in cricket: a prospective study. b r j sports med 1989, 23(3): 150-4. 8. foster d, john d, elliott b, ackland t, fitch k back injuries to fast bowlers in cricket: a prospective study. b r j sports med 1989; 23(3): 150 4. 9. foster d. management — how to get the best out o f your cricket team. sports coach 1978; 2(4): 40-7. 10. hardcastle i’ annear i’ foster dh, chakera, tm, mccormick c, khangure m, burnett. a. spinal abnormalities in young fast bowlers. j bone joint surg b r 1992; 74-b: 421 5. 11. hardcastle p lumbar pain in fast bowlers. a ust fam physician 1991; 20: 943 51. 12. ingjcr f. factors influencing assessment o f maximal heart rate. scand j med sci sports 1991; 1: 134 40. 13. johnson bl, nelson jk. practical measurements for evaluation in physical education. 4th ed. minneapolis, minn: burgess publish­ ing, 1986. 14. mason br, weissensteiner jr, spence pr. development o f a model for fast bowling in cricket. excel 1989; 6: 2 12. 15. passmore r, dumin jvga. human energy expenditure. physiol rev 1955; 35: 801. 16. pavue wr, hoy g, laussen sî carlson js. what research tells the cricket coach. sports coach 1987; 10(4): 17 22. 17. ross wd, marfell-jones mj. kin anthropometry. in: macdougall jd, wegcr ha, green, hj, eds. physiology testing for high performance athletes. 2nd ed. champaign, 111.: human kinetics books, 1991. 18. stretch ra. anthropometric profile and body composition changes in first-class cricketers. south african journal for research in sport, physical education and recreation 1991; 14(2): 57-64. 19. stretch ra. the incidence and nature o f injuries in first-league and provincial cricketers. s afr med j 1993; 83: 339 42. 20. stretch ra. 'hie incidence and nature o f injuries in schoolboy crick etcrs. s a fr med j 1995; 85:1182-4. 21. weigh tman d. browne rc. injuries in eleven selected sports. br j sports med 1971; 2: 27. □ from p a g e 9 3. dumin jvga, womcrslev j. body fat assessed from the total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. br j nutr 1974; 32: 77-97. 4. gisolfi c y cohen js. relationships among training, heat acclima­ tion, and heat tolerance in men and women: the controversy revis­ ited. med sci sports exerc 1979; 11: 56-9. 5. green m. hearts, you lose! runners world (south african edition) 1994; july/august: 52. 6. mognoni p| sirtori md, lorenzelli f, cerretelli p physiological responses during prolonged exercise at the power output corre­ sponding to the blood lactate threshold. eur j a ppl phusiol 1990; 60: 239-43. /. montain sj, coyle ef. the influence o f graded dehydration on hyperthermia and cardiovascular drift during exercise. j appl phys 1992; 73: 1340-50. 8. noakes td. lore o f runninq. cape town: oxford university press, 1992. 9. o’leary ds. 1*ir control during exercise by baroreceptors and skeletal muscle affcrents. med sci sports exerc 1996; 28: 210-17. 10. potteigcr ja, weber sf. rating o f perceived exertion and hr as indicators o f exercise intensity in different environmental tempera­ tures. med sci sports exerc 1994; 26: 791-6. 11. reilly t, robinson g, minors ds. some circulatory responses to exercise at different times o f the day. med sci sports exerc 1984; 16: 471-8. 12. richardson rs, verstraete d, johnson sc, luetkemeier mj, stray gundersen j. evidence o f a secondary hypervolemia in trained man following acute high intensity’ exercise. int j sports med 1996; 17: 243-7. 13. rowell, lb. reflex control o f circulation during exercise. int j sports med 1992; 13: s25-s27. 14. sellev ea, kolbe t, van zyl cg, noakes td, lambert mi. running intensity as determined by heart rate is the same in fast and slow runners in both the 10 and 21 km races. j sport sci 1995;-13: 405 10. □ sports medicine july 1999 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) clinical case report the consequences o f the female athlete triad in a mature woman runner: a case report lk micklesfield1 (msc) k11 myburgh2 (phd) 1 m r c /u c t b io e n e r g e t ic s o f e x e r c is e r e s e a r c h u n it, u n iv e rsity o f c a p e tow n , s p o r ts s c ie n c e in stitu te o f s o u th a frica , n ew la n d s; d e p a r t m e n t o f h u m a n a n d a n im a l p h y siolog y , u n iv ersity o f s t e lle n b o s c h , w c a pe introduction the female athlete triad is a triad o f disorders observed in adolescent and adult female athletes and includes disordered eating, amenorrhoea and osteo­ porosis,11 the severity o f which is determined primari­ ly by prior menstrual history." it is not restricted to elite athletes but includes also physically active girls and women participating in a wide variety o f sports. it has recently been shown510 that i f regular menses are resumed there is an initial increase in bone mineral density (bmd);2'4 7 however even after several years it is still significantly lower than in women who menstruate regularly, and our previous study10 suggests that in women over 30 years o f age there is little chance o f sig­ nificant increase in bmd. case report a 29-year-old female runner was investigated at base­ line, 1 year after sh e had started training for marathons, and again 3 years later. she participated in a 56 km ultramarathon three times in the period between the two tests, and her best time was 4 hours and 42 minutes. her exercise schedule consisted o f running five times a week for approximately an hour at a time. when training for a marathon competition her weekly running distance was 75 95 km. she also par­ ticipated in aerobic dance exercise four times a week and circuit weight training three times a week. she did not change her training significantly between tests 1 and 2. information such as age at menarche, the estimated number o f periods every year since menarche, the use o f oral contraceptives, fertility7 drugs or hormone injec­ tions, parity and total months o f breast-feeding, was collected and used to calculate a modified menstrual history index (mhi).1’ she had started menstruating at the age o f 14 years. correspondence: lisa micklesfield sports science institute o f south africa po box 115 newlands 7725 tel: 021 686 7330 fax: 021 686 7530 e-mail: lisam@sports.uct.ac.za at baseline she was amenorrhoeic and had experi­ enced on average 2 periodsper year for the preceding 3 years. before that she had been either oligomenor rhoeic (3 years) or amenorrhoeic (6 years) since the age o f 18. her mhi at baseline was 6.50 periods/year. her menstrual irregularity before baseline coincided with a rapid loss o f weight — 38 kg in 21 weeks, achieved through dieting. she was 170 cm tall and had a body mass o f 58 kg (her lowest weight as an adult) at baseline and 60 kg at follow-up. the most she had ever weighed as an adult was 96 kg (body mass index (bmi) = 33.2 k g /m 2) a year and a half before baseline. at baseline her per cent body fat was 32%, but it had dropped to 26% at follow-up. lean body mass had increased from 68% to 74% in this time, probably as a result o f the inclusion o f more weight training in her exercise routine. mhi had also increased to 9.25 at follow-up due to the regulation o f her menstrual cycle. she has two children aged 12 and 8 years and had breast-fed for a total o f 5 years. she had taken oral contraceptives for only 2 years after giving birth to her second child. previous dairy product intake was reported as the estimated number o f portions consumed per week dur­ ing four stages o f life. one portion was equivalent to one cup o f milk, 175 ml o f yoghurt, a rounded scoop o f ice-cream, a 250 g tub o f cottage cheese, or a cheese meal or sandwich. as a child her dairy intake consist­ ed o f canned m ilk diluted with water. she consumed an estimated 10 portions o f dairy per week during her junior school years, 21 portions/week during high school, and since leaving school between 2 and 4 por­ tions/w eek until after baseline, when her intake increased. calcium intake at test 1 was 708 mg and at test 2, 548 mg. total energy intake was 4 492 kj/day at test 1, and 3 940 k j/day at test 2, constituting 48% and 43% o f the recommended daily allowance (rda) for adult women. she took no dietary supplements or reg­ ular medication except for treatment for insomnia, for w hich condition she was using flunitrazepam crohypnol, roche). a hologic qdr-1000 (version 4.20) dual-energy radiograph bone densitometer was used to measure bmd o f the lumbar spine (ls) and left proximal femur (f). the repeatability7 o f this method has been described previously.1" ls bmd was 0.796 g /cm 2 at baseline, increasing to 0.893 g /cm 2 at follow-up, an annual increase o f 4% (fig. 1), but a total o f 12% in 3 years. the t-score for the second scan was -1.40 while 20 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:lisam@sports.uct.ac.za lum bar spine reference database reqion rate of change ±s d % ±% c hange sd l 1 l 4 +0.0318 0.0042 +3.99 0.52 fig. 1. l u m b a r sp in e b m d o f th e s u b je c t in this c a s e r e p o r t is in d ica ted rela tiv e to a r e fe r e n c e d a ta b a s e b y tw o c r o s s e s c o rre sp o n d in g to a g e 2 9 . 6 a n d 3 2 . 7 y e a r s . t h e ta b le indi­ c a te s th a t th e p e r c e n t a g e in c r e a s e o f b m d w a s 3 .9 9 % / yea r. the z-score was -1.37 (reference curve for american females, hologic qdr-1000, october 1984). bmd o f li was just below the fracture threshold o f 0.827 g /c n r and l 4 showed significant osteopenia. f bmd was normal at baseline and follow-up (1.030 g /cm 2 and 1.122 g /cm 2 respectively). the t-score for the second scan was +1.13, while the z-score was +1.16 (reference curve for american females, national health and nutritional examination survey (nhanes) update). bmd o f the femoral neck was 0.934 g /cm 2 at test 1 and 0.978 g/cm 2 at test 2. since the first scan, all areas in the left hip had increased in bmd. the annualised changes were: neck o f the femur: +1.53% per year, greater trochanter: +3.41% per year, inter-trochanteric space: +2.67% per year and the total proximal femur: +2.92% per year. all the areas o f the hip had a positive t-score at the second test. discussion the annualised changes in bmd o f this subject were substantial despite her age. this provides further evi­ dence o f the positive effect o f the resumption o f regu­ lar menses on bmd in a subject wit h a severe history ol menstrual irregularity combined with a bad profile o f other risk factors for osteoporosis. however, bmd o f the lumbar spine, which is predominantly trabecular bone and therefore more sensitive to hormonal changes, was still significantly lower than that o f age matched normals (86%) at test 2. a follow-up investi­ gation is necessary to see whether bmd will continue to increase or whether, as found by keen and drmkwater5 and micklesfield et al.,'° it will eventually plateau before reaching the level o f age-matched nor­ mals. in this case low lumbar spine bmd had a multifac­ torial origin, including lifelong lower-than-recommerid ed calcium intake, extreme weight loss (though no clinical treatment for an eating disorder) and a sub­ stantial history o f amenorrhoea and oligomenorrhoea, even before starting to run later in life. her menstrual irregularity was associated at times with breast-feed­ ing, extreme weight loss or training for an ultrama­ rathon. at baseline, the subject was informed o f the status o f her bone health and advised o f the lifestyle factors that contributed to this. she desisted irom fur­ ther weight loss and decreased year-round running training, although not when training for an ultra­ marathon (approximately 6 months per year). her menses regularised spontaneously within 1 year o f test 1. coinciding with the removal o f an ovarian cyst. regular menses probably exerted a large influence on the gain in bmd in the subsequent 3 years. however, regular weight training may also have contributed. heinrich et al:' have suggested that weight training may be a better stimulus for improving bone status than running. the subject was 32 years o f age at test 2. although several studies would predict that by this age peak bone mass would already be achieved,1,8 other studies would infer that bone mass could increase up to the age o f 34 years.6 i f lumbar spine bmd continued to increase at the present rate, i.e. 4%/year, this subject would reach the mean level o f ‘young normals’ in another 4 years. however, our other longitudinal data10 indicate a < 1%/year increase in previously irregularly menstruating women with a mean age o f 36.1 ± 5.05 years. these subjects had already menstruated regu­ larly for an average o f 11.7 ± 7.9 years, and were on average older than this subject. it is not known whether the better rate o f improvement o f bmd in this subject was related to age, severity o f previous irregu­ larity at baseline, or weight training, and whether improvement will continue at the same rate or slow down. conclusion this case illustrates that a large initial increase in lum­ bar spine bmd with the resumption o f menses is pos­ sible even at a relatively older age than previously reported. the detrimental effect o f menstrual irregu­ larity on bmd is not restricted to the very lean, elite athlete, but should be o f concern to runners o f any standard, particularly those with multiple risk factors for osteoporosis such as those in this case study. r e f e r e n c e s 1 armamento-villareal r, villareal dt, aviolo lv, civitelli r. estrogen status and heredity are major determinants o f pre­ menopausal bone mass. j clin invest 1992; 90: 2464-71. 2. drinkwater bl, nilson k, ott s, chesmit ch 111. bone mineral densitv after resumption o f menses in amenorrheic athletes. jama 1986; 256: 380-2. 3. heinrich ch, going sb, pamenter rw. perry cd, boyden tw, lohman tg. bone mineral content o f cyclically menstruating female resistance and endurance trained athletes. med sci sports exerc 1990; 22: 558-63. sports medicine july 1999 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 4. jomiavithula s, warren mi; f o x rp lazaro mi. bone density is ■ compromised in amenorrheic women despite return o f mensesa 2 year study. obslel gynecol 1993; 81: 669-74. 5. keen ad driiikwater bl. irreversible bone loss in former amen orrheic atliletes. osteoporos int 1997; 7: 311-5. 6. krolner b, nielsen sp bone mineral content o f the lumbar spine in normal and osteoporotic women: cross-sectional and longitudinal studies. clin sci 1982; 63: 329-36. 7. lindberg js, powell m, hunt m, dueey de, wade ce. increased vertebral bone mineral in response to reduced exercise in amenor­ rheic runners. west j med 1987; 146: 39-43. 8. lloyd t, myers c, buchanan jr, demers lm .' collegiate women athletes with irregular menses during adolescence have decreased bone density. obslel gynecol 1988; 72: 639-42. 9. micldcsfleld lk, lambert ev, fataar ab, noakes td, mvburgh kh one mineral densityin mature, premenopausal ultramarathon runners. med sci sports exerc 1995: 27: 688-96. 10. micklesfield lk, reyneke l, fataar ab, mvburgh kii. long-term restoration of bone mineral density is inadequate in premenopausal " ’“ " f i 1 q p n ° r inenstrual irregularity. clin j sporl med 19988loo-loo. ’ ’ h . yeager kk, agostini r, nattiv a, drinkwater bl. the female athlete iriad: disordered eating, amenorrhoea, osteoporosis. med sci sports exerc 1993; 25: 775-7. q from p a g e 14 r e f e r e n c e s 11 ?q «|s j ' f luscie aectto1^ in man. scand j clin lab invest 1v04; b&: suppl, 1-110. 2. brozek j, grande f, anderson jt, keys a. densitomctric analysis a t mi?0cslt,0n ncoe' isi0n qf some quantitative assumptions.ann ny a cad sci 1963; 110: 113-40. 3.bryntesson ^ sinning we. the effects o f training frequencies on -!% ael t o f cardiovascular fitness. med sci sports exerc 1973: 4 ' wj’ hargreaves king ds, thomas r, fielding r. metabolic characteristics o f skeletal muscle during detraining from competitive swimming. med sci sports exerc 1985a; 17: 339 •to. r>. costill dl, king ds, thomas r, hargreaves m. effects o f reduced anting on muscular power in swimmers. physician and sportsmedicine 198ob; 13: 94-101. 6. dumin jvga, wonnersly j. body fat assessed from the total bodv density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16-73 years. br j nutr 1974; 32: 7. hawley ja, noakes td. peak power output predicts maximal oxygen uptake and performance time in trained cyclists. ear j appl physiol 1992; go: 79-83. 8. hickson rc, roscnkoctter ma. reduced training frequencies and uicreased aerobic power. med sci sports exerc l y o l ; ±o: 13-o. 9. hickson rc, foster c, pollock ml, galassi tm, rich s. reduced training intensities and loss o f aerobic power, endurance, and car­ diac growdi. j appl physiol 1985; 58: 493-9. 10. houmard ja, costill dl, mitchell jb, park sh, fink wj, bums jm. testosterone, cortisol, and creatine kinase levels in male dis­ tance runners during reduced training. int j sports med 1990a; 11: 11. houmard ja costill dl, mitchell jb, park sii, hickner rc roemmich ja. reduced training maintains performance in dis­ tance runners. int j sports med 1990b; 11: 46-52. 12 houmard ja, johns ra. effects o f taper on swim performance (review). sports med 1994; 17: 224-32. 13. lowryoh passoimcau jv a flexible system o f enzymatic analysis. new york: academic publishers, 1972. 14. martin dt, scifres jc, zimmerman sd, wilkinson jg. effects of mterval tu n in g and a taper oil cycling performance and isokinetic leg strengdi. int j sports med 1994; 15: 485-91. 15. nadeau m, cuerrier j-l! brassard a. the bicycle ergometer for 19838-p4 l 6r testillg' canadian journal applied o f sports science 16' m!tpr }\ b’ ^ !ic° ougaj1 j ° . cipriano n, sutton jr, tamopolsky mâ coates g. physiological effects o f tapering in liighlv trained athletes. j appl physiol 1993; 72(2): 706-11. ' g 22 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) position statement position statement: diabetes mellitus and exercise international sports medicine federation (fim s) the following statement was approved by the fims executive committee, 26 october 1996 introduction diabetes mellitus is a common metabolic disease char •icterized by insulin insufficiency resulting in impaired ability to transport glucose across the cell membrane for its subsequent oxidation. also, muscle and liver glycogen re synthesis, triglyceride synthesis in adipose cells, inhibition o f their breakdown (antilipolytic effect), as well as protein synthesis and storage (ana­ bolic effects) are being impaired. insulin insufficiency thus leads to metabolic disturbances leading to such common symptoms as fatigue, weakness, weight loss, hunger, overeating, polyuria, and signs o f glycosuria, and ketosis. though being clinically silent for many years, dia­ betes mellitus often leads to serious pathological com ­ plications o f various organ systems (eyes, kidneys, peripheral nerves, coronary and peripheral arteries) which may substantially impair quality o f life and reduce life expectancy. there are two distinct forms o f diabetes, termed insulin dependent diabetes mellitus (iddm) and non insulin dependent diabetes mellitus (niddm). iddm is an auto-immune disease hi which the body attacks and ultimately destroys insulin producing pan­ creatic beta-cells. in addition to a genetic component, evidence supports a viral infection triggering an auto­ immune process either due to similarities with beta cell protein or sensitization to destructed beta-cells. the key pathogenetic factor o f niddm is relative insufficiency o f insulin due to insulin resistance and/or defective insulin secretion. insulin resistance is often ■ associated with hypertension, lipid disturbances, and obesity. apart from genetic dispositions, diet and obe­ sity, animal experiments as well as epidemiological data suggest that a lack o f physical activity may also contribute to a relative deficiency o f insulin. diabetes may be precipitated by, or a similar syn­ drome brought about by endocrine disorders (e.g., hypercorticosteroidism, acromegaly, hyperthyroidism, pheochroniocytoma), drugs (e.g., glucocorticoids, thy­ roid hormones, contraceptives, thiazides), and pancre­ atic or liver disease. rationale for exercise in prevention and therapy due to an insulin-like effect on muscle contraction (an increase o f membrane permeability to glucose) exercise has a potential to increase insulin sensitivity, lower blood glucose and increase its utilization. improved glu­ cose tolerance positively influences the glycemic profile that can be detected by lower concentration o f glycosy ated hemoglobin. a better glycemic profile may post­ pone and reduce the risk o f late complication. since this effect is rather short-lived, regular frequent exer­ cise sessions are needed to maintain such a benefit. also reducing body fat due to the increased energy expended and its effect on the basal metabolic rate may indirectly but significantly decrease insulin resis­ tance. in addition to obesity, exercise has the potential to favourably alter other risk factors o f cardiovascular dis­ ease, namely elevated blood lipids and hypertension. in this way an already increased risk o f coronary heart disease (3 times higher than general population) may be reduced. last but not least, exercise may reduce psychologi­ cal stress, positively influence a feeling o f well being, and improve quality o f life. exercise guidelines clearance by a knowledgeable physician is recom­ m ended prior to the initiation o f an exercise program. in addition to a general assessment, screening should include an exercise stress test to detect latent cardio­ vascular disease. requisites include an absence o f ketoacidosis and glycemia under 300 mg %. when late complications are evident., such as hypertension or renal impairment, the risks and benefits should care­ fully be considered. during the initial stages o f an exercise program, close medical supervision which includes blood glu­ cose monitoring is strongly recommended in order to adjust diet and medication (insulin or pad doses) to the exercise altered metabolic situation. modes of exercise aerobic activities carried out at moderate intensity such as brisk walking, cycling, jogging, running, or cross country skiing are preferred m odes o f exercise. since the majority o f diabetics are obese, non weight bearing exercise like cycling and swimming may pose less stress on the locomotor system and contribute to better compliance. general daily activities o f a habitu­ al nature are encouraged in addition to the exercise sessions. in the past, resistance exercise has not been recom­ mended because o f the potential for a dangerous increase in blood pressure, especially in those with vas­ cular complications. recent findings indicate that appropriate forms o f resistance exercise are safe and may potentiate the positive effects o f aerobic exercise. a circuit training approach aimed at all major muscle groups is recommended. the resistance should allow 10 to 12 comfortable repetitions. sports medicine july 1999 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) intensity o f exercise t h e exercise intensity should be between 50 and 70% ° f v 0 2maxh igher intensities excessively activate the sym pathoadrenal system with subsequent increase o f glycemia. with caution, heart rate can be used as an indicator o f intensity, bi patients with autonom ic neu­ ropathy, heart rate may not accurately reflect exercise intensity. as an alternative, perceived exertion o f mets (m etabolic equivalents) should be used for the exercise prescription. duration of exercise exercise sessions between 20 and 60 minutes are recom m ended. less than 20 minutes yields litd e car­ diovascular benefit, longer exercise tends to increase the risk o f hypoglycemia. frequency of exercise daily exercise is suggested because such an approach enables easier insulin adjustment and d iet planning. a more realistic and practical goal may be 4 to 6 sessions a week. practical remarks • patients should be educated about the effects and potential risks o f exercise, namely hypoglycemia. • the participants should wear identification indicat­ ing their diabetic condition and should exercise with a know ledgeable partner in case o f hypo­ glycem ia including loss o f consciousness. • when possible exercise should b e p erform ed at the sam e convenient time with sim ilar intensity and duration. • because o f the pro insulin effect o f exercise, insulin d epend ent dia betics should reduce insulin d oses by 20% or adequately increase food intake upon initiat­ ing an exercise program. • to avoid hypoglycem ia a small carbohydrate snack should be eaten 3 0 minutes prior to exercise. during more prolonged activity a 10 g carbohydrate snack (fruit, fruit ju ice, or soft drink) should be ingested for each 30 m inutes o f exercise. • pay careful attention to the feet ol the exercising diabetic patient. loss o f sensation due to neuropa­ thy a n d /o r im paired peripheral circulation increas­ es the risk o f injuries. g ood footwear and careful foot hygiene are essential to avoid injuries like ca l­ luses, corns and blisters that may lead to serious com plications. • warm up and cool down periods should be an inte­ gral part o f an exercise program. suggested reading c hish olm d.i. d iabetes m cuilus. in: b loom field j . i'rickcr pa, fitcli kb. (ed s). textbook o f science and medicine in sports. blackwell s cience i.id., oxford, pp. 560. 1992. w allbcrg-h cnriksson ii. e xercise and diabetes m ellitus. exer sport rev. 20, 33 9-36 8, 1992. s ciin ck lcr sh, r udcrm an mb. exercise and m d d m . d iabetes care 13, 78 5-789, 1990. t h is statem ent was prepared for the fims scientific c om m ission by a ssoc. prof. dusan hamar, md, phd, r esearch institute o f sports sciences, bratislava, slovakia. [n ote: t h is statement may be reproduced and disu-ibutcd with the sole requirem ent that it be id cn liiicd clearly as a position statement o f (lie lntcmauonal federation o f sports m cdiciiic.j 24 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ioc olympic prize i ; m k ) a i : i » m (g) parke davis ioc olympic prize b y beiino m nigg the idea of the ioc olym pic prize m ovem ent nncl m obility are am ong the m ost precious aspects o f human life. imagine a person who cannot move! a person who cannot play g o lf with m en d s, cannot go for a hike with family or friends, or cannot visit the next-door neighbours for a chat. mobility' and movem ent arc extrem ely important for the quality o f life o f humans. w ithout the ability' to move, life can be v e r y difficult. movement is important in all situations of life, from ch ild h ood to old age to high perform ance atliletics. mobility and movement are equally important for children, adolescents, athletes and the elderly. a young child learns to move and engraves movement patterns into the motor control system. if these pat­ terns are correct, early degenerative disease such as osteoarthritis may be avoided. adolescent girls and boys strengthen their muscles, bones, ligaments and tendons by providing the neces­ sary stimuli during movement, exercise and sport. bone formation in girls, for instance, is maximal during this time and a ‘bone bank’ may be established due to appropriate sport activities, reducing the risk o f osteo­ porosis. athletes expose their bodies to high and repetitive loading situations. this loading may cause damage to the body. however damage can be avoided if training and equipment are well controlled. elderly people want to enjoy their retirement age by being physically active, playing games, and spending time with their grandchildren. to d o so, they need to be m obile. consequently, understanding the factors influencing m obility and m ovem ent and the resultant loading o f the hiunan body is important. scicntific research studying m ovem ent, exercise and sport can contribute substantially to the im proved understanding o f m obili­ ty and movement. with the increased life expectancy o f humans, such research is growing in importance. t h e activities o f the international o lym pic com m ittee (ioc) centre around all aspects o f m ove­ ment, exercise and sport. the ioc is interested in high perform ance sport, physical activities for children, a d o ­ lescents, adults and the elderly, exercise and sport in developing countries, his ton ' o f exercise and sport, health and w ell-being due to physical activity and sport, and many other facets o f movem ent, exercise and sport. the ioc m edical com m ission was and is often in the lim elight because o f athlete doping cases. however, the ioc m edical c om m ission has many other less well known activities. t hanks to the initiative of its chairman, prince .alexandre de m erode, the ioc medical com m ission has many groups that con cen ­ trate on th e p ositive aspects o f movem ent, exer­ cise and sport. li 1987, one such group, the s u b com m ission for b io ­ m echanics and physiology, w anted to som eh ow ac laiowledge the importance o f science related to m ove­ ment, exercise and sport. the d iscussions o f the subcom m ission for b iom e­ ch a n ics and physiology prince alexandre de merode, resulted in two major prochairman o f the je c t p rop osa ls. first, to ioc medical commission esta b lish an ioc w orld congress for sciences related to movement, exercise, and sport; and second, to establish a highly prestigious prize for science related to m ovem ent, exercise and sport, namely the ioc olympic prize. u nder the le a d e rs h ip and g u id a n ce o f prince alexandre de m erode, chairman o f the ioc m edical com m ission, selected m em bers o f this subcom m ission went to work to develop the two ideas. dr charles dillm an p rovid ed le a d e rs h ip for the ioc w orld c ongress and acts as scientific chair o f all ioc world congresses. dr benno m nigg provided leadership for the ioc olympic prize and acts as the chair o f the selection c om m ittee for the ioc olympic prize. t h e first ioc world congress was organised by dr charles dillman in 1989 in c olorado springs. the developm ent o f the ioc olympic prize took longer to arrange, since a sponsor had to b e found. the initial contact with parke-davis, a warner-lambert division, s p o r t s m e d ic in e j u l y 1 9 9 9 2 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) was established in 1992 following unsuccessful initial contacts and discussions with several other world leading companies. after several meetings between representatives o f parke-davis (mr wayne dickerson) and the ioc m edical com mission (drs patrick schamasch, richard nelson, charles dillman, and benno m nigg), an agreement between parke-da\is (lodewijk de vink, president and coo o f warner lambert) and the ioc medical commission (prince alexandre de merode) was signed and announced dur­ ing the 1994 olympic winter games in lilfehammer. currently, parke-davis is the exclusive sponsor o f the ioc olympic prize and all other functions o f the ioc medical commission which relate to movement, exer­ cise and sport sciences (mess). the ioc olympic prize is awarded each olympic game year. the ioc olympic prize is an exciting development for the field o f sciences related to movement, exercise and sport (mess) and for anyone who loves and sup­ ports mobility and longevity. the ioc olympic prize the ioc olympic prize honours important findings resulting from outstanding basic an d /or applied research related to human movement, exercise and/or sport. these findings must represent a significant inno­ vation, contribute to the betterment o f humankind, and have significant impact upon science, health and/or society. the ioc olympic prize con­ sists o f • a gold medal • a diploma o f excellence • a cash award o f sus 500 000 the ioc olympic prize is awarded for work in four areas o f science: medical, biological, physical, and psy­ chological. examples o f research to be considered include: (a) the understanding o f the healthy develop­ ment o f the human body and its main components, (b) the effect o f exercise on health, wellness and qual­ ity o f life, (c) the prevention o f injuries in movement, exercise and sport, and (d) the improvement and optim isation o f physical perform ance through enhanced understanding of the functioning o f the human body in all age groups. the winner is announced during a banquet in new' york approximately 6 to 8 weeks before the start o f the olympic summer or winter games. the gold medal is awarded during the opening ceremony o f the ioc session before the games. effects of the ioc olympic prize the ioc olympic prize was initially (for 1996 and 1998) usg 250 000, but will be usg 500 000 for the year 2000. this substantial sum, the public announce­ ment o f the winner, and the award ceremony have sub­ stantial influence on the development of sciences dealing with movement, exercise and sport. specifically, the ioc olympic prize: • improves the recognition for research on movement, exercise and sport • attracts established scientists to study these impor­ tant questions. • attracts brilliant young scientists into the study of movement and mobility. the first winners the first prize, the 1996 ioc olympic prize, was awarded to: dr j erem y n morris and dr ralph s paffenbarger jr for their pioneering studies demonstrating how' exer­ cise reduces the risk o f heart disease. the research findings of drs morris and paffenbarger changed the practice o f medicine and inspired the fitness revolu­ tion. the ground-breaking work o f these two leading epidemiologists has brought respect to research in the area o f health and fitness and inspired additional stud­ ies that have contributed enormously to establishing the relationship between physical activity and a reduc­ tion in the incidence o f coronary heart disease. dr morris was the first epidemiologist to offer scien­ tific support for the (at that time revolutionary) hypothesis that regular physical activity reduces the risk o f coronary' heart disease. dr paffenbarger was the first to study risk factors and life habits o f male graduates o f the university o f 1 pennsylvania and harvard university. he found that physical activity is a relevant factor in reducing the risk o f hypertension, non-insulin-dependent diabetes, some forms o f cancer, and premature death in general. the winners of the first ioc olympic prize, drs morris (left) and paffenbarger (middle), with the winner of the second loc-olymplc prize, dr woo (right). /o c o i y ^ c 2 6 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the second prize, the 1998 ioc olympic prize, was awarded to: savio ly woo, phd for his pioneering contributions to the understanding o f the properties o f connective tissues, the effects of exercise on tissue properties, and the possibilities for repair o f injured tissues. his work had a significant effect on basic research in this area as well as on the medical treatment o f ligament injuries, injuries that occur frequently in physical activities. a large number of individuals benefited directly from his research. a more detailed description o f the research work of these prize winners will be presented in one o f the next publications on the ioc olympic prize. t i m e t a b l e for ti1e ioc olym pic prize 2000 1 • december 1998 meeting: selection committee in lausanne. finalising the format for nominations for the 2000 prize. • march to jime 1999 information on nomination procedure published in scientific journals and newsletters. • september 1, 1999 deadline for submission o f nomination packages to the headquarters o f the ioc medical conunission in lausanne, switzerland. • a u g u s t 2 0 0 0 announcement o f winner during a special ioc olympic prize function in new york. • september 2000 medal ceremony during the opening ceremony of the ioc session in sydnev, australia. a d d it io n a l in f o r m a t io n additional information concerning the ioc olympic prize can be found at the ioc olympic prize web site http://www.olympic.org/fam ily/ioc/medical/ olyprize l_e.html the parke-davis ioc olympic prize web site http://www.parke-davis.com/version_4/iocprize.html further information can be received from: benno m nigg, dsc (nat) chair: selection committee, ioc olympic prize: human performance laboratory the university o f calgary calgary, alberta, canada, t2n 1n4 fax: 403-284-3553 e-mail: uheinz@ucalgary.ca ioc world congress on sport sciences bv charles j dillman in 1988, the ioc m edical c om m ission d ecid ed to develop a series o f world congresses on the scientific aspects o f sport that would further the growth o f this young scientific field. the first congress was con d u ct­ ed in c olorado springs in 1989, with subsequent p ro­ gram m es being organised in barcelona (2 ) 1991, atlanta (3) 1995, and m onaco (4) 1997. t he purpose o f the world congress is to p rorid e a forum for leading scientists to exchange ideas about c i u t e n t research and to dissem inate new information about human perform ance to practitioners who are involved in developing athletes for international and olympic com petitions. t he field of sport scien ces is segm ented into four subdisciplines, namely m edical, biological, physical and psychological sciences. t he next program m e, the fifth ioc world congress for the science o f movement, exercise, and sport, will be held in sydney, australia, from october 31 to november 5 in 1999. fifth ioc world congress kni>0*ki> b\ © p a r k e d a v i s fifth ioc world congress for the science of movement, exercise, and sport endowed by parke-davis in conjunction with the australian conference of science and medicine in sport 31 october 5 november, 1999 sydney convention and exhibition centre, sydney, australia the ioc world congress will combine the very best in science and medicine related to move­ ment, exercise and sport with the warmth and hospitality of sydney — the host city of the 2000 olympic and paralympic games. sports medicine july 1999 2 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) http://www.olympic.org/family/ioc/medical/ http://www.parke-davis.com/version_4/iocprize.html mailto:uheinz@ucalgary.ca the international olympic committee’s medical commission, the sydney organising committee for the olympic games, and sports medicine australia invite you to attend this spe­ cial congress. under the theme of ‘the science and medicine of skilled performance: optimisation, injury prevention and rehabilitation’, the world’s lead­ ing exercise and sport scientists and practitioners wall present their research — theoretical, applied and clinical — in a spectacular setting, namely the sydney convention centre in beautiful darling harbour. further highlights include the opening ceremony/cocktail party, congress dinner, olympic venue tour, sports afternoon, and optional tours in and around sydney. the congress also offers a unique opportunity for sport and team healthcare professionals to meet representatives of socog’s medical and doping control programmes to discuss planning for the sydney 2000 olympic and paralympic games. programme highlights professor savio woo, phd, from the muscle research centre, university of pittsburgh and wanner of the prestigious ioc olympic prize, wall give the opening presentation at the congress. keynote and invited speakers professor ed coyle, usa professor bente pedersen, denmark professor cy frank, canada professor richard lieber, usa professor joachim mester, germany dr jos de koning, netherlands professor simon gandevia, australia professor lew hardy, uk symposia articular cartilage repair keeping people physically active (1): motivation through the lifespan strategies to enhance fatigue resistance research on muscle mechanics ethics in sport women in the olympic games clinical and physiotherapy symposia workshops application of muscle mechanics in sport keeping people physically active (2): public health programmes supplements to enhance performance: the evi­ dence? biomechanics feedback for the elite athlete workshops in sports medicine, sports physiother­ apy, sports podiatry and sports dietetics. free papers oral, video and poster presentations in the disci­ plines of medical, biological, physical & behav­ ioural sport sciences parke-davis symposium the cardiovascular dysmetabolic syndrome: diabetes/insulin resistance, hypertension and hyperlipidaemia taking place on sunday 31 october will be of particular interest to internists and general practitioners. important dates abstract application forms & abstracts due by 15 may 1999 early bird registration closes 30 june 1999 accommodation bookings by 17 sept 1999 further information on congress congress secretariat, sports medicine australia po box 897 belconnen act 2616 australia ph.+6126251 6944 fax: +6126253 1489 e-mail: smanat@sma.org.au visit the official sydney 2000 olympic games web site: http: / / www. sydney. olympic. or g / 28 sports medicine july 1999 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:smanat@sma.org.au s o u t h a f r ic a n j o u r n a l o fsports medicine sportgeneeskunde journal of the s.a. sports medicine association tydskrif van die s.a. sportgeneeskunde-vereniging v o l u m e 5 n u m b e r 2 m a y 1990 editor in c hief: d rc noble m b bch. fcs(sa) associate editors: proftsnakes, m b clib, \1d d> dati’ii'iun velden m b chb tsit’ll) m prax medl pretoria) advisory board: medicine: dr i cohen m b c hb , d . obst. r c o g orthopaedic traumaiologv: o r p fire) bs c (eng). m b bch? wits). m med(onho) 'wits) bug e hugo m b c hb , mmcd<chir> orihopaedics: d r j c usdin m b b c h, f r c s (edin) cardiology: col d p my burgh sm m b chb fa cc physical educaiion: prof hannes botha d phil (phys ed) gynaecology: dr jack adno m b bch (wits), m d (med) , dip o (s’ g (wits) s a s g v s a s m a contents editorial comment c ausation of injury ................................................... 3 preventative sports medicine a ltitude fails to increase susceptibility o f ultram arathon runners to post-race upper respiratory tract infections ...................................... 4 rugby injuries r ugby injuries of the cervical spine and spinal cord — has the situation im proved? ........... 9 sport injuries a survey of all sport injuries ..................................... 16 sports medicine physical exam ination of the ankle and the foot ...... 20 p u b l is h e d by t h e s o u t h a f r ic a n spo rt s m e d ic in e a ss o c ia t io n h a t f ie l d f o r u m w est 1067 a r c a d ia st r e e t h a t f ie l d p r e t o r ia . 0083 p ic tu re> courtesy o f p h o to file /im a g e b a n k the journal of the sa s p o m medicine association is published bv medpharm publicauons. 3rd floor n’oodhulpliga centre. 204b h f verwoerd drive, randburg2194 tel (011; 787-4981/9 the views expressed in this pubhcauon are those o( ihe authors and not necessarilv those of the publishers p r im e d b v t h e n a t a l w itn ess p r im in g hi id p u b lish in g c o m p a n y (p i v) ltd sportgeneeskunde vol 5. nr 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a non-steroidal anti-inflammatory . relieves pain . reduces inflammat . restores mobility . reduces the cost o) trauma therapy available now in three rfos; pan a m o r ' 25 tablets panamor^ at 50 tabl] and in tro d u cin g pan amor* 75 in i£ c t l€ release from inflammatory pain l e n n o n . w l im it e d icr ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) e d it o r ia l causation of injury one of the major roles a sports medicine doctor plays is advising on prevention of injury. to understand how in­ jury can be prevented one must understand how injury is caused. except for the overuse injuries which to a large extent occur in endurance sports most injuries are due to over­ loading of a body part. this may be due to intrinsic fac­ tors e.g. contraction or stretching of a muscle beyond which that muscle cannot adapt. the second factor is extrinsic which means that an ex­ ternal force is applied to a body part which cannot with­ stand it. tearing of knee ligaments following a rugby tackle is a good example of this. the overloading may be singular or repetitive, in the latter giving rise to chronic injuries such as tennis elbow. thus there are two basic factors in the causation of in­ jury • the force; • the adaptability of the body to resist the force. let us consider the second factor first. a large number of variables are associated with ones abil­ ity to adapt to force. age in youth the epiphyses are more liable to intrinsic over­ loading than any other part of the muscle-skeletal system. severe disease of the heel (9-12 years), osgood-schlatter disease of the upper tibial tuberosity, (13-15 years) and apophyseal avulsion injuries of the pelvis (16-18 years) are common growth injuries. from 18 years to 30 years the epiphyses are usually fused and muscle tears are more common. after 30 years of age injuries to tendons are more common as these be­ come progressively weaker with ageing. extrinsic forces are much more variable injuries occur­ ring to all tissues depending on the site of application. muscles tend to protect other tissues. in adolescence muscles are relatively weak and protection of the spine may be inadequate resulting in spinal injuries. in older athletes there is progressive deterioration of tissue with a loss of tissue elasticity. over loading forces are more likely to result in injury to weakened tissue. ligamentous laxity this is somewhat controversial but it would appear that people with lax ligaments are more likely to injure liga­ ments resulting in dislocations. palettar subluxation and dislocations are typical examples of this where minimal violence may cause injury. fitness good fitness implies that the sportsman has adapted to the stresses that the specific forces have placed on his body. fitness is specific; a long distance runner will re­ quire muscle endurance and a weight-lifter muscle strength. to obtain fitness progressive loading is manda­ tory. failure of adaptation occurs when the training pro­ gramme has been too rapid. if the forces are too great no amount of fitness will prevent injury. warm up an adequate warm-up means that the tissues have not been put into the functional mode i.e. sudden overload­ ing is liable to cause injury. at least one degree increase in body temperature and a full range of joint movements are the m inim um requirements. technique incorrect technique causes overloading and is a major source of injury. force if the force exceeds the maximum loading a tissue can tol­ erate tearing will occur no matter how great the fitness of the athlete. thus in a sport like rugby a tackle of excessive force will cause injury. if the tackle is high or late, injury is more likely to occur. excessive forces in rugby may occur in a number of situations. the scrum, especially the loose scrum, and the tackle are the two danger areas. in conclusion before one can offer advice on prevention of injuries it is essential to understand all the factors which cause injury. dr. clive noble m bb ch, fcs(sa) editor-in-chief ----------------------------------------------------------------------------------------------------------------3 sportsgeneeskunde vol. 5 nr. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) p r e v e n t a t iv e s p o r t s m e d ic in e altitude fails to increase susceptibility of ultramarathon runners to post-race upper respiratory tract infections distance runners are more pre-disposed to urt infections than non-runners e m p eters introduction reduced host resistance to infection fol­ lowing participation in an ultramara­ thon event, has been attributed to dam­ age to the local mucosal membranes of the upper respiratory tract (urt). physical properties of the mucous mem­ branes have been reported to change and to result in impaired lymphocyte, neutrophil and macrophage function (solomon and armkraut, 1981). it was hypothesized that the amount of damage to the mucous membranes should be greater at altitude due to: • the reduced relative humidity and greater “dryness” of the air inhaled by runners; and • the increased pulmonary ventilation at a given running speed. this study compared the percentage incidence of u rt infections following a 56 km ultramarathon run in pretoria edith m peters m sc(m ed) in sport science, u c t division o f physical education west campus university o f the witwatersrand p o wits 2050 (reported relative humidity: 52%; alti­ tude ±160m) to the incidence obtained amongst runners who had completed a 56 km at sea level (reported relative humidity: 79%) in cape town (peters and bateman, 1983). method the officially recorded maximum and m inim um temperature and relative hu­ midity readings in cape town on 10 april 1982 were obtained from the weather bureau in pretoria. questionnaires were completed by ±130 entrants for the milo korkie ultramarathon, a 56 km race from pretoria (±1600 m above sea level) to johannesburg (1800 m above sea level) during the seven days prior to the race. information requested included run­ ning history, state of health and training record prior to participation in the race. each athlete nominated a control of similar age and with whom they resided or were in frequent contact before the race. two weeks after the race, 116 runners were questioned with regard to u rt symptoms experienced during the post­ race period and their running perform­ ance in the 56 km race. the incidence of symptoms among the control group during this period was also recorded. data with regard to environmental conditions on the day of the race were obtained from the weather bureau in pretoria (table 1). statistical analysis of the results in­ cluded the use of chi-square analysis and calculation of co-efficients of corre­ lation. results o f the 117 subjects who were ques­ tioned, 106 (90,6%) were male and 11 (9,5%) were female. five (4,3%) of the subjects were less than 25 years old; 84 (72,4%) were aged between 25 and 40 years and 28 (23,9%) were over the age of 40. thirty-one (28,7%) of the 108 sub­ jects who completed the race reported non-allergy derived u rt symptoms during the two weeks following the race as compared to 14 (12,9%) among the control group. this is a significantly higher percentage incidence (x2=22,8; p<0,005). only seven (23%) of the symptomatic runners were matched with symptomatic controls. seven of the runners remained symptom-free de­ spite being in contact with a symptoma­ tic control. the greatest majority (57%) of the to­ tal sample of runners who completed the race (n=108) had completed less than 85 km.wk-1 in training. thirty-five percent of this subsample who had com­ pleted less than 85 k m .w k 1 became symptomatic. only eight percent of the symptomatic group (n=108) had completed more than 120 km .wk'1 in 4 --------------------------------------------------------------------------------------------------sports m e d ic in e vol. 5 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) p r e v e n t a t iv e s p o r t s m e d ic in e table 1: environmental conditions at the time of 56 km races in cape town (sea level) and pretoria (moderate altitude) venues of relative maximum minimum mean 56 km races humidity temp. temp. temp. pretoria 52% 25°c 14,8°c 20°c cape town 87% 24°c 14,0°c 16°c table 2: incidence of u r t symptoms amongst runners and their matched controls (n = 108) asymptomatic symptomatic control control symptomatic runners 24 7 asymptomatic runners 68 7 table 3: time taken to complete the race in symptomatic and asymptomatic groups time taken to complete race <4h30 4h30-5h00 5h00-5h30 5h30-6h00 >6h00 symptomatic subjects 7 10 6 6 2 asymptomatic subjects 15 18 22 18 2 percentage symptomatic 31,8 35,6 21,4 25 50 n 22 28 28 24 4 table 4: nature and duration of symptoms (n=46) c ld a y 13 days 47 days > 7 days total -r unning nose 2 5 2 6 15 sneezing 3 4 7 sinusitis 2 1 1 4 nasal 4 9 2 11 26 sore throat 9 2 3 14 cough 1 1 2 4 fever — — 2 2 total number of symptoms 4 19 5 18 46 training. only 12 of the 108 who finished the race, did not compete at maximal effort, indicating dissatisfaction with the times in which they completed the race. o f the 31 runners who completed the race and developed u rt symptoms there­ after, 29 (94%) indicated that they were satisfied with their performance in the event. the greatest number of symptomatic runners (n=10) finished the race be­ tween 4h30 and 5 hours. however, of the total subsample which finished the race in less than 5 hours (n=50) 34 per­ cent (17) were symptomatic (table 2). w ith increasing time taken to complete the race, the percentage symptomatic decreased to a 24 percent incidence amongst the group completing the 56 km between 5h30 and 6 hours. it in­ creased again in the sample taking more than 6 hours to complete the race (n=28). the most prevalent symptoms after the race were nasal (57%) followed by sore throats (30%). thirty-nine percent of the symptoms lasted for more than seven days and only two reported fever accompanying the u rt symptoms. four (9%) of the symptoms reported were trivial lasting less than one day. eleven (33,3%) of the symptomatic sub­ jects treated their symptoms with vari­ ous cold cures and/or anti-pyretics, whereas one subject reported taking anti-biotics. in an attempt to include only patients who presented with symptoms of an in­ fective origin, persons with a recent his­ tory of allergic rhinitis (n=5) were ex­ cluded. as sinusitis is usually infective in origin, this was included in the nasal symptoms category and was not isolated as a separate category. lower respira­ tory tract conditions (e.g. bronchial, tracheal) were not included in this sur­ vey. discussion this epidemiological study confirms previous findings of a significantly higher incidence of u rt infections amongst runners than their matched controls following participation in an --------------------------------------------------------------------------------------------------------------- 5 sportsgeneeskunde vol. 5 nr. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) p r e v e n t a t iv e s p o r t s m e d ic in e ultradistance marathon event (peters and bateman, 1983; douglas and han­ son, 1978). the higher incidence of u r t symptoms amongst runners fol­ lowing participation in ultradistance running events has been attributed to: • the impairment of host resistance to infection resulting from the pro­ longed stress; and/or • local damage to the mucosal surfaces resulting from their drying and cool­ ing during mouthbreathing (peters and bateman, 1983). in this study, the exposure to moder­ ate altitude with the concomitant in­ crease in pulmonary ventilation, higher ■ mean temperature and greater dryness of the air (table 1) did not result in an increased incidence of u r t infections among a sample of runners who com­ pleted a 56 km race when compared to the incidence among a similar sample who ran a race of the same length at sea level. these results thus appear to indi­ cate greater contribution of impaired systemic immune mechanisms than re­ duced local mucosal function to the re­ duced resistance to infection experi­ enced by the athletes. it is well documented that the physio­ logical and biomechanical stress of exer­ cise results in elevated blood catechola­ mine and corticosteroid levels, which, in turn, influence immuno-competence. adrenaline concentrations in the blood have been reported to rise as much as 8 times during prolonged exercise (galbo el al, 1977) thereby possessing substan­ tial potential to modulate immune func­ tion. elevated adrenaline levels are known to reduce the number and func­ tion of circulating lymphocytes, result­ ing in both lymphocytosis and neutro­ philia (gary el al, 1983). suppression of immune function has also been reported following elevation of blood cortisol levels (solomon and armkraut, 1981) and manifests with: n = 1 41 n u m b e r of s u b je c ts n = 1 41 n = 1 08 s y m p t o m a t ic a l a lt it u d e ( 1800m ) | s y m t o m a i t c a t s e a le v e l r u n n e rs c o n tro ls (non ru n n e rs ) f ig u r e 1. a c o m p a ris o n of the in c id e n c e of u r t s y m p to m s a m o n g s t ru n n e rs a nd c o n tro ls at m o d e ra te a ltitu d e f 1 8 0 0 m ) a nd sea level. n =60 45 40 35 05 o cd s ' 30 o) "o s 25 n e3 2 20 10 n=37 a s y m p to m a tic s ym p to m a tic <85 n=9 1 1 1 f l p < 0 . 0 0 5 86-120 >120 f ig u re t rain ing d ista n c e (k m .w k '1) 2: u r t s ym p to m s and tra in in g d is ta n c e p rio r to c o m p e tin g • selective depletion of t lymphocytes and reduced t cell cytotoxicity (mc­ carthy and dale, 1988); • macrophage receptor is the blockage andchemotaxis (lewicki et al, 1987); • reduced distribution and activity of natural killer (nk) cells. (mackin­ non, 1989). eskola ei al (1976) have reported re­ duced lymphocytosis at the end of marathon races while edwards et al (1984) reported significant changes in the b cell/t cell lymphocyte ratio. re­ cently, research workers have been able to discriminate changes in the subsets of t lymphocyte compartment showing a reduction in the helper to suppressor ratio following exercise (berk et al, 6 --------------------------------------------------------------------------------------------------sports m e d ic in e vol. 5 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) pr e v e n t a t iv e s p o r t s m e d i c i n e n a tu re o f s y m p to m s | [ n a s a l j 2 s o re th ro a t | h c o u g h n d f e v e r d u ra tio n o f s y m p to m s f ig u r e 3: n a tu re a n d d u r a tio n o f s y m p to m s c o l d a ir d r y a ir h y p e r v e n t il a t io n m o u t h b r e a t h in g d rying nf m n c n s a l s e c re tio n s • | e ffe c tiv e n e s s o f m u c o c ilia r y c le a r a n c e m e c h a n is m in n o s e a n d b ro n c h ii • | q u a lity + e f fe c tiv e n e s s o f s e c re te d a n tib o d ie s (ig a 's ) e n z y m e s ( ly s o z y m e s ,la c to fe r in , p e ro x id a s e in tr a b r o n c h ia l m a c r o p h a g e s f ig u re 4 ' l o c a l d a m a g e re s u ltin g in im p a ir m e n t o f im m u n e fu n c tio n . 1985). further, neutrophilia (petrova et a l, 1983) eosinophilia and eosinpenia (keast et al, 1988) have been recorded following exercise. a recent study by lewicki et al (1987) suggests that non-specific immunity may be the greatest contributor to in­ creased susceptibility of suppression of resistance to infection. this is sup­ ported by the studies of tomasi el al (1982) tested eight nationally ranked nordic skiers before and after comple­ tion of a 50 km race. when compared to a control group, lower levels of salivary iga were found in the skiers before the race and antibody levels dropped even lower during the race. petrova el al (1983) produced evidence of reduction of both serum and secretory immuno globin which was related to increasing intensity of exercise workload. smith et al (1988) have described that with greater oxygen turn-over during exercise, greater production of oxygen derived free radicals can play a substan­ tial role in depressing immune function. it is therefore possible that the athlete who is deficient in the anti-oxidant vita­ mins (c, e and a) may have a greater susceptibility to infection than the run­ ner who possesses more positive vita­ min status. this is a factor which we are at present investigating and which may well have increased the results of this and previous epidermiological surveys. this study showed that the less trained runners, i.e. runners who have completed less than 84 km .w k'1, had the highest incidence of infection. it is poss­ ible that the combination of little train­ ing with less oxygen radicals available to activate the neutrophils (less respiratory burst) and the greater degree of acute stress experienced by the unadapted or­ ganism with greater impairment of host resistance to infection, may have con­ tributed to this result. it was not poss­ ible to address the “overtraining” phenomenon as so few of our sample had been completing more than 160 km.wk'1 in training and no record was kept of the intensity of the training. as found in our previous study, there was a high incidence of infection (± 32%) 'amongst the faster athletes. those athletes who completed the race in less than 5 hours had encountered a greater stress situation than the slower athletes. on the other end of the spec­ trum, the athletes who were on the road for more than 6 hours, also showed a greater incidence of infection. it ap­ pears that prolonging the stress situ­ ation may also result in greater impair­ ment of host resistance to infection. three factors thus point to decreased general host resistance to infection and not local mucosal being the primary cause of the increased incidence among ultra-distance runners. firstly, despite the environmental conditions being more conductive to local mucosal dam----------------------------------------------------------------------------------------------------------------7 sportsgeneeskunde vol. 5 nr. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) p r e v e n t a t iv e s p o r t s m e d ic in e age than in our previous study, this was not reflected by a greater incidence of infection. secondly, the greater stress experienced by the less trained athletes correlated with a higher incidence of in­ fection and thirdly, the fact that in both studies, it has been in the faster group of athletes who also experienced greater impairment of their immune response at systemic level, that the greater incidence of infections was recorded. it is however, incumbent upon re­ searchers to continue with biochemical investigation into the exact mechanisms underlying this apparent reduced resist­ ance to infections following prolonged exercise. a ckn ow ledgem en t: the fourth year biokinetics students (1989) o f the d iv ­ ision o f physical education at the uni­ versity o f the witwatersrand, are thanked fo r their assistance in collecting the data obtained fo r this publication. r e f e r e n c e s 1. berk ls, tan sa, n iem an d c , eby w c : the suppressive effect o f siress from acuie exhaustive exercise on t lymphocyte helper/ suppressor cell ratio in athletes and non­ athletes. abstract. medicine and science in sports and exercise, 17: 706(1985). 2. crary b, hauser sl , borysenko m , k utz i, hoban c: epinephine-induced changes in the distribution of lymphocyte subsets in the peripheral blood o f hum ans. journal of im ­ munology, 131: 1178-1181,(1983). 3. douglas d j and hanson pj: upper respira­ tory infections in the conditioned athlete. medicines and science in spons and exer­ cise, 10: 55(1978). 4. edwards a j, bacon r h , elms c a , veradi r , felder m : changes in the populations of lymphoid cells in humarr peripheral blood following physical exercise. clinical and ex­ perimental immunology, 58: 420-427 (1984). 5. eskola j, ruuskanen 0 , soppi e, viljanen m k , jarvinen m : effect of sport stress on lymphocyte transformation and anti-body formation. clinical and experimental im­ munology, 3: 339-345 (1978). 6. galbo h , christensen n j, horbst jj: glucose-induced decrease in glycogon and epinephrine responses to exercise in man. journal of applied physiology, 42: 525-530 (1977). 7. keast d , cameron k . and morton a r: exercise and the im m une response. sports medicine, 5: 248-267(1988). 8. lewicki r , tchorzewski h , denys a , golinska a: effects of physical exercise on some parameters o f im m unity in con­ ditioned sportsmen. international journal of sports medicine, 8: 309-314 (1987). 9. m ack innon lt: exercise and natural killer cells. w hat is the relationship? sports medicine, 7:141-149(1989). 10. m ccarthy d a and dale m m : the leuco cytosis of exercise. a review and model. sports medicine, 6: 333-363 (1988). 11. nicholl pj, w illiam s bt: medical problems before and after a popular marathon. british medical journal, 285, (1982). 12. peters e m , bateman ed : ultramarathon running and upper respiratory tract infec­ tions, 5/4 medical journal, 64: 1 582-584, (october 1983). 13. solomon g f , armkraut aa: psycho neuro-endocrinological effects in im m une response, annual review microbiology, 35: 178-179,(1981). 14. smith ja , telford r d , hahn a g , mason ib , weideman m j: training, oxygen radi­ cals and the im m une response, excel, 4: 3-6, (1988). 15. tomasi t b, trudeau fb, czerwinski d , erredge s: im m une parameters in athletes before and after strenuous exercise. journal of clinical immunology, 2: 173-178 (1982). l-carnitine one vital ingredient guarantees your formula's success. because lonza guarantees its purity. l-carnitine is the naturally-occurring energy source necessary in increased amounts during strenuous physical activity; as a supplement, it replenishes the system w ith nutrients essential for endurance and stamina. in constant demand locally and abroad , l-carnitine is produced by lonza to exacting standards o f research and development. supported locally by lewis & everitt, it is now rea dily available. in your next a p plica tion , trust l-carnitine. g uaranteed at least 99% pure for perfectly reliable results. nature's nutrition. pure and simple. lewis & everitt a a n a n glo alpha industrial m inerals o peration r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r u g b y i n j u r i e s rugby injuries of the cervical spine and spinal cord has the situation improved? at s ch er abstract paralysis due to injury of the cervical spinal cord in rugby players, is a subject of great concern. since the publication of previous reports on these injuries, considerable attention has been paid to amending the rules governing rugby and improving the standard of refereeing. in an attempt to assess whether these measures have reduced the incidence of injury or altered the type of injury sustained, an analysis of injured rugby players admitted to the spinal cord injury centre at conradie hospital during the period 1981 to 1987 has been made. results of this study indicate that there has been no decrease in the incidence of these serious injuries. the scrum and tackle remain the most important cause of injury. flexion violence applied to the head and neck is still the major injuring force. foul play, in particular the high tackle remains an important and avoidable cause of injury. a new finding is the identification of a group of rugby players who have sustained temporary paralysis without evidence of orthopaedic injury. introduction in 2 previous papers1,2 i have reported on patients admitted to the spinal cord injury centre at conradie hospital in cape town who have sustained para­ lysis due to rugby injuries to the cervical spinal cord. these reports dealt with a total of 50 players admitted during the period 1964 to 1980. in a series of papers, i identified the important phases of the game responsible for the majority of injuries, specifically the tight scrum,1 the tackle,3 rucks and mauls.4 a t scher m b c h b d m r d department o f radiology tygerberg hospital and university o f stellenbosch p o b ox 63 t y g e r b e r g 7505 ----------------------------------------------------------------------------------------------------------------9 sportsgeneeskunde vol. 5 nr. 2 since the first paper,1 published in 1976 there has been much discussion as regards reducing the incidence of these serious injuries and various changes to the rules have been introduced. in an attempt to ascertain whether there has been a decrease in the inci­ dence of, or change in the mechanism of, these injuries following on changes in the rules, an analysis of rugby players admitted to the spinal cord injury centre with injuries of the cervical spi­ nal cord during the 7 year period 1981 to 1987 has been made. method and materials the case histories and radiographs of all patients admitted during the period 1981 to 1987 with spinal cord injury due to rugby, have been analyzed. specific attention has been paid to the circum­ stances of injury, orthopaedic injuries as reflected on x-ray and the neurological deficit present on clinical examination. the cases were subdivided into groups according to the phase of the game dur­ ing which the injuries were sustained. these cases were further subdivided into groups using the admission radiographs of the cervical spine as indi­ cators of the mechanism of injury. results a total of 38 players with cervical spinal cord injury either permanent or tem­ porary, have been identified. age of patients the age distribution is shown in table i. nine (24%) of the players were 17 years of age or under at the time of in­ jury. orthopaedic levels of injury table 2 shows the distribution of the levels of injury. noteable is the high percentage (32%) of players who sustain injury at the c4/c5 level. two players injured at the c2 level and 10 players r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r u g b y in j u r ie s table 1: age distribution age no. of players age no. of players 14 1 15 1 16 3 17 4 18 — 19 3 20 — 21 1 22 4 23 5 24 3 25 2 26 1 27 2 28 1 29 1 30 1 31 3 32 — 33 34 — 35 — 36 r ~ 37 — 38 — 39 1 40 — 41 42 ip total: 38 table 2: orthopaedic levels of injury level number level number c2 2 c2/3 _ c3 c3/4 1 c4 1 c4/5 12 c5 2 c5/6 5 c6 3 c6/7 2 c7 c7/t1 no. orthopaedic injury: 10 table 3: phases of the game in which injury occurred no. % scrums 15 39% tackles: (a) tackier 3 i 42% (b) tackled 13 j rucks/mauls 4 10% collision 1 2,6% unknown 2 5% table 4: degree of paralysis due to injury in different phases of the game incomplete complete scrum 9 6 tackle 12 4 ruck 3 1 other 1 1 collision 1 showed no evidence of orthopaedic in­ jury on x-ray examination. this is in contrast to the large series reported by silver5 in which no high cervical spinal injuries were found nor any case re­ ported without evidence of injury on x-ray. phases of the game in which injury occurred (table 3) the majority of injuries were sustained either in the scrum (39%) or during tackles (42%). this is in keeping with the findings in previous analysis.1,2 degree of paralysis due to injury in different phases of the game (table 4) it can be seen in table 4 that the major­ ity of players (61%) sustained incom­ plete paralysis. 39% of players were completely paralysed. notable is the high incidence of scrum injuries amongst this group. type of orthopaedic injuries sustained in different phases of the game (table 5) reference to the table shows that there is a wide spectrum of orthopaedic inju­ ries. notable is the high number of flexion-dislocations sustained conse­ quent upon collapse of the scrum. mechanism of injury as reflected on admission radiograph (table 6) reference to the table shows that flexion was the most frequent important injury force. twenty-five players (66%) sus­ tained their injuries as a result of pure flexion violence or a combination of flexion and rotation. discussion comments on players injured in scrums fifteen (39%) players were injured in scrums. this figure correlates well with the 40% incidence of scrum injuries noted in my previous analyses1,2 and also with international experience. burry and gowland6 reporting on a series of new zealand rugby players with cervical spinal cord injuries, noted a 35% incidence of scrum injuries. w il­ liams and mackibben7 in a similar analy­ sis in wales reported a 44% incidence. thirteen of the 15 players were in­ jured as a result of collapse of the scrum. one player was injured by crash­ ing of the two packs of forwards with the injured player being caught un­ aware. details of the position of all the players injured are not available, but the majority of scrum injuries involved players in the front row, either props or hookers. (figure 1) as shown in pre­ vious studies,12 scrum injuries often re­ sult in severe neurological deficit. six of the players sustained complete, perma­ nent quadriplegia. analysis of the type of orthopaedic injury sustained in the scrum, table 5, reveals that the majority of injuries were anterior dislocations, either bilateral or unilateral. this is in keeping with the findings in the pre­ vious study.1 the common mechanism of injury is flexion trauma as the major­ ity force with a rotational component in those cases with unilateral facet disloca­ tion. in cervical spinal cord injury due to causes other than rugby, the percent­ age of patients with bilateral locking of facets is much lower. in a series of 335 unselected cervical spinal cord injuries, only 15,5% (52) cases of bilateral lock­ ing of facets were recorded.8 the mech­ anism of these injuries was for some time, controversial. roaf,9 using cadaveric spines, was unable to produce dislocation unaccompanied by fracture by hyperflexion alone and found that some degree of rotation must also be present. this was not in keeping with clinical observations, in particular as re­ gards scrum injuries. clear histories were obtainable from players in the front row who stated that as the scrum collapsed, their foreheads struck the ground and while the rest of the pack kept on pushing, their necks were pro­ gressively flexed and paralysis suddenly ensued. in 1978 bauze and ardran,10 in an experimental study showed that pure dislocation unaccompanied by fracture 1 0 --------------------------------------------------------------------------------------------------sports m e d ic in e vol. 5 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) from bencard n a b u m e to n ethe anti-inflammatory that improves functional mobility t ^ marketed by bencard division of beecham pharmace beg. no, 74/03968/07 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r u g b y in j u r ie s table 5: t ype of orthopaedic injury sustained in different phases of the game b.l.f u.l.f. subluxation “tear drop” fracture compression fracture hangman’s fracture no orthopaedic injury scrum 7 3 2 _ _ _ 5 tackle _ 2 — 1 3 2 6 ruck 1 2 1 — — — other 2 1 table 6: classification of cases in relation to mechanism of injury as reflected on radiological examination flexion subluxation dislocation with bilateral locking 3 of facets 10 wedge fracture 3 “tear-drop” fracture 2 flexion/rotation unilateral locking of facets 7 vertical compression “burst” fracture hyperextension avulsion fracture of the vertebral body fractures of the spinous processes and laminae — posterior vertebral displacement fracture dislocation haemorrhage into the retrotracheal soft — tissue hyperextension injury in the elderly — without radiographic evidence 1 hangman’s fracture 2 no orthopaedic injury 10 could occur with flexion force. w ith the neck slightly flexed, and the vertex fixed on the ground, the normal cervical lor­ dosis is lost and the spine straightened. in this position, the force is transmitted down the long axis of the spine. when the force exceeds the energy-absorbing capacities of the involved structures, far less force is required to dislocate the vertebrae and dislocation can occur without fracture. comment on tackle injuries sixteen (42%) of players were injured during a tackle. three players were in­ jured attempting to tackle an opponent, while the remaining 13 were tackled. neurological deficit was less severe and only 4 players sustained complete paralysis. the spectrum of orthopaedic injury is shown in table v and varies considerably from the orthopaedic inju­ ries due to scrumming. noteable are the large group of players who showed no orthopaedic injury on x-ray and also the two players with high (c2) fractures. the wider variation of orthopaedic in­ jury and lesser degrees of neurological deficit in tackle injuries as compared to scrums is in keeping with the more var­ ied mechanism. nevertheless, reference to table vi shows that flexion injuries predominate. in these cases the element of restraint of the vertex is often absent and the amount of damage to the spinal cord often less severe. one player was injured as a result of a double tackle. (figure 2) six players were injured as a result of high tackles around the neck. the mechanism of injury in double tackles11 and high tackles12 has been ana­ lyzed in previous studies. the overall percentage of injuries sustained in tackles has increased, which is in keeping with the findings of silver.5 o f particular note and cause for concern, is the finding that 6 players were injured by a high tackle. in silver’s series,5 only one is recorded as having been injured due to a high tackle. silver also reported 4 players injured as a re­ sult of double tackles. comment on injuries sustained in rucks and mauls only 4 (10%) of the players were injured in these phases of the game. one player reported that he was injured while try­ ing to break loose, 2 players jumped on him and while he was lying on the ground trampled and kicked him. the other players appear to have been in­ jured by players falling on top of them while they were lying on the ground. there is a surprising discrepancy be­ tween the figures found in the survey of silver5 and ours in this respect. he re­ cords a marked increase in the number of players injured in these phases of the game. a similar finding has been made in the 20 year survey of cervical spinal injuries in wales.7 the reason for this marked decrease in the percentage of players injured in rucks and mauls is not clear. 12 --------------------------------------------------------------------------------------------------sports m e d ic in e vol. 5 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r u g b y in j u r ie s figure 1: anterior dislocation at the c4/c5 level with unilateral facet disloca­ tion. this player was a 14 year old hooker who sustained complete quadriplegia and died some weeks after injury. players with spinal cord injury without radiological evidence of orthopaedic injury five of these players were injured in tackles and the rest in collapsing scrums. although spinal cord injury without evidence of orthopaedic injury x-ray is found commonly in patients admitted to spinal cord injury units, these are generally elderly patients with spondylosis. the observation of this large group of young rugby players suf­ fering this type of injury is new and has not been recorded in other surveys. a recent paper has however reported on similar findings in rugby players and is the subject of another paper in prepar­ ation. conclusion during the period 1964 to 1980, 50 rugby players with cervical spinal cord injury were admitted to the spinal cord figure 2: typical double tackle with one player attempting to grasp of the tackled player. figure 3: frustrated opponents applying force to the neck while trying to gain possession of the ball. _________________________________________________________________________________________________________________________________________ 13 sportsgeneeskunde vol. 5 nr. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r u g b y in j u r ie s injury centre at conradie hospital,2 an average of 3 players a year. during the period under review in the present paper (1981 to 1987) 38 players were ad­ mitted, an average of 5,4 players a year. this indicates that despite increased public awareness of serious rugby spinal injuries and considerable amendments to the rules, the incidence of rugby spi­ nal cord injuries in the cape province has not decreased. silver and g ill14 comment on the gratifying decrease of serious cervical spinal cord injuries in rugby players in the united kingdom, wales and new zealand, but note that the only country where there has not been a decrease in the incidence is south africa. as commented on in previous papers, 1,2 and also in reports from over­ seas,7 flexion remains the most import­ ant mechanism of injury (figure 3). the two phases of the game where most serious injuries occur are again ident­ ified to be the scrum and the tackle. in the scrum, flexion usually combined with restraint of the vertex or combined with rotation produces most injuries. the mechanism of injuries in tackles is more varied, but flexion violence again predominates. foul play was responsible for a signi­ ficant number of injuries. apart from the single instance, where a player was injured by crashing of the scrum, a dis­ turbing number of players were injured by the high tackle. despite previous comment on the danger of this illegal play,12 no decrease in these avoidable in­ juries appears to have taken place. r e f e r e n c e s 1. scher at. rugby injuries to ihe cervical spi­ nal cord. 5 a frm edj 1977; 51: 473-475. 2. scher at. rugby injuries of the spine and spinal cord. clin sports med 1987; 6(1): 87 99,12. 3. scher at. the high rugby tackle an avoi­ dable cause o f cervical spinal injury? 5 afr medj 1978;53;1015-1018. 4. scher at. rugby injuries to the cervical spine sustained during rucks and mauls. 5 a frm edj 1983;64: 592-595. 5. silver jr . injuries of the spine sustained in rugby. b rm e d j 1984; 288: 37-43. 6. burry h c , gowland h . cervical injury in football a new zealand survey. br j sports med 1981; 15: 56-60. 7. w illiam s p and m c k ib b in b. unstable cervi­ cal spine injuries in rugby a 20-year review. injury 1987; 18(5): 319-332. 8. braakman r , penning l. injuries of the cer­ vical spine. excerpta medica. amsterdam 1971. 9. roaf r. a study o f the mechanics o f spinal injuries. j bone j l surg 1960; 42b (4): 810 823. 10. bauze r j, ardan g m . experimental pro­ duction o f forward dislocation in the hum an cervical spine. j b o nejt surg 1978; 60b (2): 239-245. 11. scher at. the “double tackle” another cause of serious cervical spinal injury in rugby players. 5 afr med j 1983; 64: 595 596. 12. scher at. the high rugby tackle a con­ tinuing menace. 5 afr sports med 1981; 11: 3. 13. torg js, pavlov h , genuario se et al. neurapraxia o f the cervical spinal cord with transient quadriplegia. j bone j l surg 1986; 68 a (9): 1354-1370. 14. silver j r , g ill s. injuries o f the spine sus­ tained during rugby. sports med 1988; 5: 328-334. aer linc us fglnavs ts 14 sports m e d ic in e vol. 5 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) will give youi more le n t e r k m m d taotets k & t / 2 5 3 | | ip re c n b in g inlormaiion consuii mor freedom to walk, jump, run and work r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s p o r t in j u r ie s a survey of all sport injuries examined at the bureau for student health of the university of the orange free state during the period january 1985 december 1985 ea m prinsloo aim the incidence of sport injuries was ex­ amined. the type of injury sustained in various sport events was examined. special attention was given to rugby and athletic injuries. the study was done to determine the need for sport medicine education in south africa. m e t h o d s the clinical records of the doctors and orthopedic surgeons were used. all per­ sons included in the study were sports­ men of the university of the orange free state who sustained injuries during the period january 1985 december 1985. attention was given to the type of sport, type of injury, level of compe­ tition, recurrent injuries, referral to or­ thopedic surgeons, sex of sportsmen and special investigations done. r e s u l t s (table 1) there was a total of 438 injuries; 5% of consultations in 1985. there were 145 referrals to ortho­ pedic surgeons. table 1: injuries in various sporting events sport number % rugby 246 56,2 athletics 60 13,7 hockey 23 5,3 marathon 19 4,3 netball 14 3,2 soccer 12 2,7 squash 9 2,0 gymnastics 8 1,8 j udo/boxing/karate 8 1,8 cricket 7 1,6 jogging 7 1,6 swimming/diving 5 1,1 volleyball 4 0,9 tennis 4 0,9 water-skiing 3 0,7 weightlifting 3 0,7 cycling 1 0,2 biathlon 1 0,2 parachuting 1 0,2 rowing 1 0,2 tug at the rope 1 0,2 fencing 1 0,2 total 438 100% d r e a m prinsloo r u g b y in ju r ie s (graph 1) 193 injuries were sustained during hos­ tel league: 25 at club level, 25 at provin­ cial level, 1 springbok player. the high incidence at hostel level may be due to different factors. more players participate at this level. the players are usually not very fit. players play in unusual positions. the motive to win is very high in hostel league. a> ■o® 3 m _ 5 8 8 gf l w o ^ c ™ graph 1: rugby injuries 60 graph 2: (rugby) injuries per month 1 6 --------------------------------------------------------------------------------------------------sports m e d ic in e vol. 5 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s p o r t in j u r ie s causes of injuries graph 2 indicates the number of inju­ ries per month. 24% (58/246) were re­ current injuries. rugby players tend to play with injuries. the doctor should put the health of his patient first and stand up to coaches who want to force injured players to play. the player, team doctor and coach should work together as a team. they should have confidence in the doctor and he has to show enough interest and knowledge of the game. knee injuries (graph 3) 24% (59/246) were knee injuries. posterior cruciate ligament medial kapsular ligament tear posterior oblique ligament partial tear medial collateral ligamenl examination see figures 1-7. c £ to © h 1 o o-e <d c © e « & 2 ffl ® e 2 <o ? s q co cm .bd c e 9fc © (0 fo c <d w .51 § ^ -o3 — o) ^ w ij » 8 f ,g 1 i ® « a ® 1 1 i i 8 s i i * 0) posterior view right knee figure 1:1+ medial instability knee in full extension posterior view right knee figure 2:3+ medial instability knee in full extension tear anterior and posterior graph 3: knee injuries medial view right knee figure 3:1 + medial instability knee 30 flexion tear medial kapsular ligament tear anterior cruciate ligament tear posterior oblique ligament tear medial collateral ligament medial view right knee figure 4:3+ medial instability knee 30 flexion tear medial collateral ligament tear medial kapsular ligament tear anterior cruciate ligament (not shown) tear posterior oblique ligament sportsgeneeskunde vol. 5 nr. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s p o r t in j u r ie s referrals 42 knee injuries were referred to ortho­ pedic surgeons. 27 patients were oper­ ated upon. 10 medial menisectomy 5 lateral menisectomy 7 anterior cruciate reconstruction 1 lateral collateral tear 1 iliotibial band 2 arthroscopy for loose fragment knee post-operative physiotherapy plays an important part in treatment. ankle injuries 39 ankle injuries 32 lateral ligament injuries 9 medial ligament injuries 2 lateral malleolar fractures treatment most grade ii + injuries are put in plas­ ter of pans. physiotherapeutic rehabili­ tation after removal of plaster of paris. gravity sign figure 7: posterior cruciate ligament tear (posterior instability) popliteustendon iliotibial band arcuate ligament partial tear lateral collateral ligament tom lateral capsular structure posterior view right knee figure 5: lateral instability with knee in full extension (2+) figure 6 lateral view right knee (1 + instability knee 30 flexion) lateral view right knee (3 + instability) 18 sports m e d ic in e vol. 5 no. 2 tear arcuate ligament tear popliteal ligament tear lateral collateral ligament tear lateral capsular ligament popliteustendon tearpopliteus tendon tear lateral collateral ligament tear arcuate ligament tear lateral capsule tear iliotibial band r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s p o r t in j u r ie s table 2: marathon injuries injury n um ber % stress fracture 6 31,6 iliotibial band 5 26,3 achillestendonitis 4 21,0 “shins” 2 10,5 sports anemia 1 5,3 chondromalasia 1 5,3 total 19 100% table 3: type of athletic injury injury no. % hamstring 14 23,3 knee 11 18,3 chondromalasie (5) bursa (3) osteochondritis dissecans (1) anterior cruciate ligament (1) tibiofibular ligament (1) “shins” 6 10,0 iliotibial band 4 6,7 adductor hip 4 6,7 ankle 4 6,'/ ligament (3) osteofyte (u back 3 5,0 foot 3 5,0 stress fracture 3 5,0 quadriceps 2 3,3 calf 2 3,3 hand/elbow 2 3,3 achillestendonitis 1 1,7 compartment syndrome 1 1,7 total 60 100% table4: injuries in various items item number % middle/longdistance 22 36,7 longjump 12 20,0 sprints 12 20,0 javelin 6 10,0 high jump 4 6,7 steeplechase 2 3,3 hurdles 1 1,7 shotput 1 1,7 table 5: injuries in track events item injury number sprints hamstring 6 quadriceps 2 knee/bursa 2 back 1 “shins” 1 middle/long hamstring 4 distance iliotibial band 4 knee 4 “shins” 3 stress fracture 2 calf 1 back 1 compartment sindrome 1 ankle ligament 1 gout 1 steeplechase chondromalasia 1 adductor hip 1 shoulder injury total of 33 injuries: 15 acromioclavicular ligament tears 5 sternoclavicular injuries 6 rotator cuff injuries 5 anterior dislocations 2 capsular injuries neck injuries only 9 injuries: 8 soft tissue 1 cervical disk athletic injuries analysis 60 athletic injuries 19 marathon injuries (seetable 2) anatomical analysis see table 3. type o f injury in various items see table 4, 5 and 6. stress fractures tibiotalor pinching. conclusion there is much room for research into sport injuries and there is a need for post-graduate education in sport medicine in south africa. there should be better co-operation between sportman, coach and team physician. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s p o r t s m e d ic in e physical examination of the ankle and foot r f s p en cer introduction adequate physical examination of any part of the musculoskeletal system should be preceded, whenever possible, by comprehensive history and general examination. one must bear in mind that pain is often caused by compensa­ tory stresses in response to malaligne ment.1 it is therefore essential, when as­ sessing an ankle or foot problem, to exclude the possibility of pathology in the spine, hip or knee. routine physical examination should follow traditional guidelines. these can be summarised under the following headings: • look • feel • move • test stability the process of looking should com­ mence as early as possible and should embrace all aspects of the athlete’s gen­ eral demeanour and gait. it should then focus on the limb in question and assess discrepancies of contour, difference in girth when comparing left and right, and the posture when standing observed from both front and back. at this stage it may be appropriate to ask the patient r f spencer f r c s , f c s (sa ) orth senior lecturer in orthopaedic surgery u niversity o f n a ta l m edical school p o b ox 17039 congella4013 n atal, south africa. to stand on tiptoe to assess possible problems in the tendo-achilles mech­ anism. one should then proceed to look at the particular area in question, paying attention to previous scars, sinuses and areas of erythema or bruising. palpation can then be carried out for differences in skin temperature, areas of tenderness, and prominent bony landmarks. d ur­ ing the palpation process the foot may be gently moved both passively and ac­ tively to assess crepitus within the ten­ don sheaths and joints. particular atten­ tion should then be paid to localized areas of tenderness. movements should be assessed both actively and passively. active movements should be assessed first in order to delineate the range of relatively painfree movement. passive movements may then be carried out to assess the range more fully. once again, crepitus both in the joints and tendon sheaths should be noted. finally, stabil­ ity may be tested. it is important when assessing the medial and lateral ligamen­ tous structures of the ankle to hold the heel and not the forefoot when doing this. varus and valgus stresses can be applied to assess any possible instability. at this stage special investigation appro­ priate to the diagnosis may be required. tendo achilles pathology the patient with an achilles tendon problem may have difficulty standing on tiptoe and contracting the calf mus­ cles. more than one pathology may be present in this region2. the mesotenon may be diffusely inflamed and tender and give rise to clearly visible swelling in the region when viewed from behind and compared with the other side. this condition is referred to as achilles peri tendonitis. at the same time, or in isolation, either of the bursae in the region may be inflamed. there is a bursa deep to the achilles tendon and one superficial to it. the latter may become inflamed as a result of wearing tight running shoes. focal areas of mucoid degeneration or partial rupture of the tendo-achilles may be assessed by palpation. where a complete rupture has occurred the patient will commonly complain of a sudden pain in the region not unlike the feeling of having been kicked in the back of the heel. the most useful test for assessing this situation is the thompson’s (or simmonds’) test. this is best performed with the patient prone with the feet overhanging the end of the examination couch. it may immediately become obvious that there is a gap in the tendinous mechanism. the foot on the affected side does not naturally assume a slight equinus position. the diagnosis is confirmed by squeezing the calf muscles on both sides. on the af­ fected side the foot will not move into a position of plantar flexion, whereas it will do so on the unaffected side. it is pertinent to note that the patient may be able to actively plantar flex the foot in the presence of a complete rupture of the tendon. other tendons in the region of the ankle joint may become affected by in­ flammatory processes and tenosynovi­ tis. similarly, the peroneal tendons may be subject to subluxation and disloca­ tion. 2 0 --------------------------------------------------------------------------------------------------sports m e d ic in e vol. s no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s p o r t s m e d ic in e sever s disease this condition frequently affects young and adolescent athletic individuals, and gives rise to pain and local tenderness in the region of the insertion of the tendo achilles into the calcaneus. the con­ dition may be a traction apophysitis of the tendon insertion. the radiological features include flattening and sclerosis of the posterior calcaneal apophysis. nerve entrapment syndromes two nerve entrapment syndromes may become troublesome to the athlete. the superficial peroneal nerve emerges from the deep fascia on the anterolateral aspect of the leg. it may become constricted when it passes through the fascia giving rise to pain on the dorso­ lateral aspect of the foot and over it’s site of emergence. similarly, the poste­ rior tibial nerve may be constricted within the flexor retinaculum on the posteromedial aspect of the ankle. this gives rise to pain and paraesthesiae on the plantar and medial aspects of the foot. palpation may reveal tenderness and sometimes a positive tinel sign over the area of constriction. the diagnosis may be confirmed by inflating a blood pressure cuff over the calf to a pressure between the systolic and diastolic levels for a minute or so, thus providing the onset of typical symptoms. fractures and sprains of the ankle the typical fractures and fracture dislo­ cations around the ankle joint are exten­ sively covered in standard text books. the clinical findings are usually quite characteristic with extensive ecchy moses, crepitus and severe bony tender­ ness in the region. attention must be paid to the neurovascular status of the foot. sprains may involve either the medial or lateral structures at the ankle joint. the internal or medial type of strain is less common and involves the super­ ficial part of the deltoid ligament. this is most easily assessed by examining the patient from behind and comparing the two sides, a clear swelling being visible over and inferior to the medial malleo­ lus on the affected side. on the lateral side, the ligament is divided into three parts; the anterior and posterior talo­ fibular and the calcaneofibular liga­ ments. frequently, only the anterior talo-fibular ligament is damaged giving rise to the common “sprained ankle”. in this condition swelling over and antero­ lateral to the lateral mallolus is visible and pain is elicited by inverting the foot. however in more severe injuries all three bands may be ruptured giving rise to possible instability. an injury of this kind is thought by many to be an indi­ cation for surgical treatment. the diag­ nosis is best made by taking stress views in both the ap and lateral projections. the ap stress view is obtained by ap­ plying a varus strain to the heel while taking the film. instability is demon­ strated by an opening of the lateral as­ pect of the ankle mortice. (figure 1). lateral medial figure 1: diagram of ap varus stress xray showing lateral instability and talar tilt. figure 2: diagram of lateral “anterior drawer”. xray showing anterior subluxation of the talus. anterior posterior -----------------------------------------------------------------------------------------------------------------21 sportsgeneeskunde vol. 5 nr. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s p o r t s m e d ic in e the lateral view, or so called anterior drawer test, is best obtained by placing the patient’s heel on a sandbag and pushing downwards on the tibia. if in­ stability exists, the tallus can be seen to subluxate forward in the ankle mortise. (figure 2). some surgeons believe that the ap views should be augmented us­ ing an arthrogram, which will show dye leaking extensively into the lateral soft tissues. it should be remembered that follow­ ing rupture of the lateral ligamentous structures, whether these have been managed by operative or non-operative means, the normal proprioceptive structures within the ligament have been damaged. therefore, although no residual instability may be demon­ strable clinically, the patient may com­ plain of a feeling of instability on the lateral side. this condition is referred to as “stable instability”. other conditions giving rise to instability loose bodies within the ankle joint are occasionally a cause of instability. these may arise from anterior traction spurs in the so called “footballer’s ankle”, or from osteochondritic fragments which have become detached. the most com­ mon cause of the latter is the condition of osteochondritis dissecans, which fre­ quently affects the superior weight bear­ ing surface of the talus. another lesser known condition is the so called menis coid lesion. this consists of a synovial and fibrous frond of tissue which grows into the ankle mortice as a result of re­ peated trauma to the area. it may impinge between the weight bearing surfaces and give rise to symp­ toms. degenerative disorders “footballer’s ankle” may affect the younger patient, giving rise to traction spurs from the capsule and decreased joint space with sclerosis, stiffness and pain. in older athletes, post traumatic osteoarthritis becomes a factor to con­ sider. the patient will complain of mechanical pain, clinical examination may reveal diffuse synovial swelling, tender osteophytes, and the range of motion may be decreased. the radio­ logical findings are characteristic. foot pronation this may give rise to considerable pain and disability in the runner. several conditions may predispose to the devel­ opment of the pronated foot.3 • joint laxity • heet valgus • genuvarus • tight tendo-achilles • subtalar varus • forefoot supination it is worth re-iterating the importance of assessing the whole limb before con­ centrating on the foot problem. exam­ ine the running shoes for uneven wear and observe the patient from behind, as the position of the heels can only be ac­ curately assessed from this view. congenital abnormalities a number of congenital anomalies within the foot may be important to the athlete. perhaps the most common of these is the condition of metatarsus pri­ mus varus which has a strong hereditary influence and may rise to hallux valgus. assessory ossicles may also occur. the “os trigonum” is a frequently found radiological anomaly. most common in causing clinical symptoms is the so called “os naviculare” on the dorsome dial aspect of the foot. this is simply an accessory navicular bone. tarsal coalition is an unusual but im ­ portant cause of pain in the adolescent. this gives rise to “peroneal spastic flat foot”. in this condition the patient com­ plains of pain on the posterolateral as­ pect of the ankle with exercise. this pain is related to the peroneal tendons which on clinical examination appear to be tender and the muscles in spasm. the medial arch of the foot is frequently dropped, hence the “flat foot” descrip­ tion. it is important to take adequate xrays, including harris oblique views of both heels in order to establish the possible presence of a tarsal coalition. ct scanning may also be helpful. iselin’s disease this condition, which affects the ado­ lescent, is another example of a chronic traction injury. in this instance, this involves the insertion of the peroneus brevus tendon into the base of the 5th metatarsal. local tenderness may be elected in this area and radiological fea­ tures usually consist of a presence of a small flake of bone displaced from the apophysis, near the insertion of the ten­ don. stress fractures nearly 50% of stress fractures which oc­ cur in athletes involve the foot.4 the important clinical features con­ sist of gradually increasing and chronic pain which eventually make it imposs­ ible to continue with athletic activity. local tenderness is invariably present, and the radiological features in­ clude a periosteal reaction, and some­ times a fracture line. it is important to differentiate these conditions from malignancies, and therefore a precise history is essential. in the case of the “jones fracture”, which occurs about 2cms from the base of the 5th metatarsal the injury consists of a traction type of stress fracture, rather than one due to repeated compressive loading. this in­ jury should be differentiated from the avulsion fracture of the base of the 5th metatarsal, as the treatment is quite dif­ ferent and the prognosis without bone grafting much worse in the case of the jones fracture. fractures and dislocations of the foot these may follow many patterns, the clinical history and examination usually being revealing. the important feature is the development of considerable swelling within the first 24-48 hours. common areas of involvement in­ clude the subaltar joint, the talonavicu­ lar and calcaneocuboid joints (the so-called chopart dislocation) and the tarsometatarsal joint (lisfranc disloca­ tion). deformity may be obvious on clinical examination. the metatarsal bones may be fractured as a result of 2 2 ___________________________________________________________ sports m e d ic in e vol. 5 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 1 »•" d e ta ils of c o m p o s itio n , in d ic a tio n s c o n tra in d ic a tio n s , s id e e ffe c ts . d o s a g e a n d p re c a u tio n s a r e *-lable o n r e q u e s t fro m r o c h e p r o d u c t s (p t y ) l t d . p o b o * 4 5 8 9 j o h a n n e s b u r g 2 0 0 0 . a d l.n e s 2 2 1 0 20 mg tertojtjcam v 3 1 tilcqftll 20 "s'! fooche ® tilcotil 20 mg each pacjt. ccŝajin$ pius 1 ™ -h m 'm l as solvent b a t o n 2 s c k e e p o u t o f r e a c h o f c h i l d r e n | s3] reg. nos. vials: v/3. 1/238: h/34/128 tilcotil = trademark oncetilcotil tenoxicam 20m g nonsteroidal anti-inflammatory drug rapid anti­ inflammatory & analgesic action for the treatment of sports injuries t h e first i.v. and i.m. 20m g once daily parenteral administration for abridged product information please see page 24. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s p o r t s m e d ic in e ‘tilcotil’ roche components: t e no xica m indications: s y m p to m a tic tre a tm e n t o f the fo llo w in g p a in fu l in fla m m a to ry and d e g en erative d is o rd e rs o f the m u s c u lo s k e le ta l system : rh e u m a to id a rth ritis ; o s te o a rth ritis ; a n k y lo s in g s p o n d y litis ; e xtra a rtic u la r d is o rd e rs , e .g . te n d in itis , b u rs itis , p e ria rth ritis , g o u ty a rth ritis (fo r ta b le ts ). d osage: 2 0 m g once d a ily at the sam e tim e each day. the p are n te ra l fo rm is used fo r one o r tw o d ays. for tre a tm e n t in itia tio n in acute g o u ty a rth ritis 4 0 m g (2 ta b le ts ) once d aily fo r tw o days fo llo w e d by 20 m g once d a ily fo r a fu rth e r five days is re c o m m e n d e d . c o n tra-in d icatio n s: k no w n h y p e rs e n s itiv ity to the d ru g . p atients in w h o m s a lic y la te s o r o th e r n o n s te ro id a l a n ti­ in fla m m a to ry d ru g s (n s a id s) in d u ce s y m p to m s o f a sth m a , r h in itis o r u rtic a ria . p atients w ho are s u ffe rin g o r have s u ffe re d fro m severe diseases o f the u p p e r g a s tro in te s tin a l tra c t, in c lu d in g g a s tritis , g a s tric and duo de na l u lc e r. b efore a na esthe sia o r s u rg e ry , ‘ t il c o t il ’ s h o u ld n o t be g ive n to p a tie n ts at ris k o f kidn ey fa ilu re , o r t o p a tie n ts w ith increased ris k o f b le e din g. c o n c u rre n t tre a tm e n t w ith s a lic y la te s o r o th e r n said s s h o u ld be a vo id e d . p re g n a n c y and la c ta tio n . p recautions: s im u lta n e o u s tre a tm e n t w ith a n tic o a g u la n ts a n d /o r oral a n tid ia b e tic s s h o u ld be avo ide d u n le ss the p a tie n t can be c lo s e ly m o n ito re d . renal fu n c tio n (b u n , c re a tin in e , d e v e lo p m e n t o f o ed em a , w e ig h t g ain , e tc .) s h o u ld be m o n ito re d , w he n g iv in g a nsaid to the e ld e rly o r to p a tie n ts w ith c o n d itio n s th a t c o u ld increa se th e ir ris k of d e v e lo p in g renal fa ilu re . packs: t a ble ts 20 m g : 10 ’s, 3 0 ’ s. v ial pack c o n ta in in g 1 vial active su b s ta n c e and 1 a m p o u le w a te r fo r in je c tio n . crushing injuries. in all cases, early diagnosis is import­ ant in order to allow treatment (includ­ ing early reduction of any dislocation) to begin. osteochondroses these have been described involving many of the tarsal and metatarsal bones. the most commonly observed exam­ ples include kohler’s disease of the navicular and frieberg’s infraction of the head of the 2nd metatarsal. re­ peated trauma has been thought to be an important aetiological factor, but this is not certain. localised tenderness will be present and may sometimes suggest a stress fracture. however, the radiologi­ cal features are characteristic. the areas affected become flattened and sclerotic. neuromas morton’s neuroma, usually in the third interdigital cleft on the plantar aspect of the foot, is the most common condition of this kind to affect the athlete. how­ ever, a less frequent condition known as joplin’s neuroma may involve the cuta­ neous nerve on the dorsal aspect of the hallux. this is frequently due to re­ peated trauma from tight running shoes. local exquisite tenderness is characteristic of these conditions. in the case of the morton’s neuroma trans­ verse compression of the metatarsal heads may elicit pain on clinical examin­ ation. in addition there may be paras thesiae distal in the area of supply, and a local positive tinel sign. hallux valgus hallux valgus is a problem which more often affects the female runner. the aetiological factors include the wearing of tight fashionable shoes and the inher­ ited condition of metatarsus primus varus. clinical examination frequently reveals a tender bunion overlying the head of the 1st metatarsal with the well known lateral angulation of the hallux. the sesamoids may become involved and be locally tender on the plantar aspect. hallux rigidus this commonly affects long distance runners and is a condition of degenera­ tive arthritis of the 1st metatarso­ phalangeal joint. the history is import­ ant in that the patient will complain bitterly of pain and stiffness in the joint. local tenderness may be present. the range of movement is grossly decreased and is painful. the xray findings are those of a degenerative arthritis of the joint. other causes of forefoot pain the sesamoid bones may become in­ flammed or fractured in the absence of other surrounding pathology. they are, on occasion, subject to stress fracture. however, the simple verruca vulgaris may give rise to pain and local tender­ ness in the plantar skin and should be considered. it is worth remembering that ingrow­ ing toenails and athletes foot are not un­ common in runners and may be difficult to treat. summary the above account of the physical examination of the foot and ankle is by no means comprehensive with respect to all the conditions which may be found. however the problems which commonly affect the athlete have been detailed. it is most important to re­ iterate that full assessment of the patient is necessary in all cases, and that mala­ lignment problems may give rise to ankle and foot pain. references 1. maron b r . “orthopaedic aspects o f sports m edicine” in sports medicine, appenzeller o , and atkinson r. ed. urban and schwar zenberg, ballimore-munich, 1983. 2. schepsis a a and leach r e . “surgical m an­ agement o f achilles tendinitis”. the american journal of spons medicine vol 15(4), 308-315,1987. 3. noble ca. “excessive distances are major causes o f injury”. sa sports medicine, no 3, 4-5,1978. 4. maiheson g o , clement d b , mckenzie d c . “stress fractures in athletes. a study of 320 cases”. the american journal of sports medicine. vol 15(1). 46-58,1987. 24 --------------------------------------------------------------------------------------------------sports m e d ic in e vol. 5 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) south african journal of s p o r t s m e d ic in e s p o r t g e n e e s k u n d e jo u r n a l o f t h e s.a. spo r t s m e d ic in e a sso c ia t io n t y d s k r if van d ie s.a. s p o r t g en ee sk u n d e -v e r e n ig in g n a tio n a l a d v iso ry b oard e d ito r in c hief: clive noble a sso cia te e d ito rs: p r o f td noakes d aw ie van velden a d v iso ry b oard: t r a u m a to lo g y : etienne hugo p h y s io th e r a p y : joyce morton n u tr itio n : m ieke faber b io k in e tic s : m artin schwellnuss e p id e m io lo g y : d erek yach r a d io lo g y : alan scher p h a rm a c o lo g y : john straughan p h y s ic a l e d u c a tio n : hannes botha in te rn a l m e d ic in e : francois r e lie f in tern a tio n a l a d v iso ry b oard lyle j m icheli a s s o c ia te c lin ic a l p r o f e s s o r o f o r th o p a e d ic s u rg e r y chester r kyle r e a s e a rc h d ir e c t o r , s p o rts e q u ip m e n t r e s e a rc h a s s o c ia te s p r o f h c w ildor hollm ann p r e s id e n t d e s d e u ts c h e n s p o rta rz te b u n d e s howard j green p r o f e s s o r , d e p a r tm e n t o f k in e s io lo g y george a brooks p r o f e s s o r , d e p a r tm e n t o f p h y s ic a l e d u c a tio n neil f gordon d ir e c to r , e x e r c is e p h y s io lo g y edm und r burke a s s o c ia te p r o f e s s o r , u n iv e r s ity o f c o lo r a d o volum e 6 number 2 april/m ay 1991 contents editorial comment progress in sports medicine .................................. 3 sports injuries tendinitis ...................................................................... 4 rugby dislocation o f the cervical spine in a rugby player due to "crashing" o f the s c r u m .................................. 8 nutrition iron status and athletic perform ance ..................... 10 physiotherapy update the physiotherapy management o f chronic muscle tears o f the calf in long distance runners ................ 14 conceptions/m isconceptions in sports m edicine types o f muscle contraction as biomechanical c o n c e p ts ............................................... .......................... 16 drugs in focus spare your joints ........................................................ 20 abstracts abstracts from the clinical journal o f sports medicine the official journal o f the canadian academy o f sports journal .................................. 21 anabolic steroids masa takes stand against dispensing o f anabolic steroids ......................................................................... 23 sasgv j s a s m a p u b l is h e d by t h e s o u t h a f r ic a n p h o tographs co u rtesy o f the im a g e bank spo r ts m e d ic in e a sso c ia tio n h a t f ie l d f o r u m w est 1067 a rc a d ia s t r e e t h a t f ie l d p r e to r ia , 0083 t h e jo u rn a l o f the sa sports m edicine a ssociation is p ublished by m e d p h arm publications, 3rd f loor n oodhulpliga c e n tre, 204b h f v erw oerd d rive, r a ndburg 2 1 9 4 . t el: ( o il) 7 8 7 -4 9 8 1 /9 . t he view s e x pressed in this publication are those o f the authors and not n ecessary those o f the p ublishers. p r i n t e d b y t h e n a t a l w i t n e s s p r i n t i n g a n d p u b l i s h i n g ( o n i p a n y ( p i y ) l t d r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ^iffiflyoospor ib ifonazole 1r/13.9.2/204 solution ir /1 3.9.2/203 cream bayer-miles no matter what the life style, mycospor provides the patient with powerful penetration and long lasting action. due to its lipophilic properties, it offers up to 72 hours1 of activity with a single application once daily mycospor offers powerful symptomatic relief and reduces the duration of treatment making it highly economical. long lasting penetrating power. 1. sanchez, j. l. et al “ clinical management of tinea corporis/cruris and tinea (pityriasis) versicolor: two to three-week treatment with bifonazole 1 % solution” . advances in therapy. vol. 3. no. 5. september/october 1986.272-280. bayer-miles, 27 wrench rd, isand01600. reg. no. 53/00355/0 the real test of an antifungal must be its efficacy in conditions that create the infection in the first place r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial progress in sports medicine since i first became interested in sports m edicine 30 years ago, many changes have taken place. in my main field o f interest, i.e. traum a­ tology the changes have been remarkable. take the tom meniscus for example. as a registrar we were taught to do a total menis­ cectomy as the only proper method o f treat­ ing a tom meniscus. numerous papers since then have shown that this form o f treatment greatly increased the incidence o f osteo arth-ritis and has led to many an old sports­ man being crippled and even requiring knee replacement. the present technique o f arth­ roscopic partial meniscectomy has greatly reduced the degree o f osteoarthritis and more recently the repair o f peripheral tears o f menisci has resulted in the restoration of normal articular archi-tecture. in the old days a patient was immobilised following this procedure for two to three weeks and was kept in hospital for at least 10 days. today the usual treatment is early mobilisation and a day in hospital. the operation is even being done on an outpatient basis. m any sportsmen are back at sport within 10 days. rehabilitation in those days consisted of straight leg raising exercises and then active mobilisation following cast removal. now early rehabilitation using isokinetic and other techniques only allows return to activity when 90% o f strength has been achieved. this has led to a remarkable reduction in reinjury. the anterior cruciate ligament injuries in the past were often neglected because o f the poor results o f prim ary repair. this neglect led to meniscal injury and progressive ar-ticular cartilage degeneration leading to early osteoarthritis. modern techniques with isometric positioning o f the reconstruc­ ted ligament has greatly improved the results in cases o f chronic instability. the use o f artificial ligaments has not been clarified but in chronic instability may be a valuable adjunct in salvage cases, i.e. cases where all other techniques have failed. added to this, the understanding o f initial degeneration in transplanted tendon used in the reconstruction has made the scientific rehabilitation o f these knees far safer. assessment o f tendon strength has also helped in replacing o f the damaged anterior cruciate ligament. isometric placement has been improved by the use o f suitable jig s and other similar instruments, a great improvem ent on the "eye-balling" technique o f yesteryear. in acute disruptions o f the anterior cruciate ligament, besides adequate repair, augmen­ tation with a tendon or artificial ligament have greatly improved results. in collateral ligament injuries o f the knee immobilization in plaster casts has greatly restored rehabilitation and return to active sport. m odem techniques using early physiotherapy and strenuous strength exercise program m es as well as support with side-splint braces in the more severe cases have resulted in early, improved healing and return to sport. a sim ilar situation has occurred in ankle ligament injuries where splinting with such splints as an "aircast" brace have allowed the player more rapid mobilisation but in many cases have protec-ted the player dur­ ing play without radically impeding his ability. in these days o f professional sport these improvements have saved players large amounts o f money. a similar situation can be found in all aspects o f sports medicine. h owever in many fields we still have a long way to go. in traumatology the answers to such prob­ lems as "shin splints", and osteitis pubis in runners and other sportsmen are lacking. the prevention and treatm ent o f degen­ erate joint disease in the older sportsman is an example o f another area o f difficulty. i hope i'm around in 30 years time to see the future im provements in sports medicine. d r clive noble mbbch, fcs (sa) editor-in-chief ---------------------------------------- 3 sportgeneeskunde vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports injuries tendinitis clive noble tendinitis is a "scrapheap" di­ agnosis in sportsmen. it is a di­ agnosis in many ways which is similar to "having a virus" in general medicine, sometimes correct but very often wrong. tendinitis certainly does oc­ cur, in fact it is the commonest overload injury in the older athlete. as its name implies, tendinitis affects tendons. any tendon in the body may be in­ volved. the "itis" part o f its name is only partially correct. inflammation is a minor part o f the pathology and its function is most likely reparative. cel­ lular trauma is the major pa­ thology. this, in the chronic case, causes secondary cellular degeneration which in turn causes inflammatory cell re­ pair. this tendon trauma is caused by cellular overloading which may be the result o f a singular large overload result­ ing in rupture or repetitive minor overloading resulting in microtearing and secondary degeneration. it is far more common in the older athlete where the tendon progressively weakens with age. in youth tendinitis is extremely rare as here the growth areas or apo­ physes are the weakest link in the musculo-skeletal chain. thus in the 9-12 age group traumatic calcaneal apophysitis (severs disease) is the most common site o f overloading. in the 13-15 age group trau­ matic upper tibial apophysitis becomes more common. this is usually called osgood sch latters disease named after the men who described it independ­ ently in 1903. in the 16-17 age group the pelvis apophyses become the weakest area. here, a number o f sites are involved depending on the overloaded muscular group. usually by the age o f 18 most o f the growth points are fused to the main body o f the bone but in the iliac crest region they may stay open as late as 22 years o f age. after the age o f 18, muscle is more likely to be overloaded causing muscle fibre rupture which may be either partial or complete. from the a g e o f 3 0 , tendon w eakn ess causes the tendon to becom e the fo re ru n n e r in the injury stakes. the affected muscles are usu­ ally those crossing two joints such as the hamstring and quad­ riceps. muscle rupture on overloading diminishes stead­ ily after the age o f 30 years with the exception o f the calf muscles which may rupture well into middle age. from the age o f 30, tendon weakness causes the tendon to become the forerunner in the injury stakes. thus tendon in­ jury is a problem o f the ageing athlete. tendon consists mainly o f collagen and elastin fibres. in the relaxed position it is wavy in appearance but on loading can stretch to approximately 4% o f its total length. on further loading rupturing o f the tendon fibres occurs. micro­ scopically collagen fibres have a helical pattern and are joined together by cross linkages. the cross linkages are not well developed giving the tendon more plasticity. as ageing occurs these cross linkages are better developed resulting in more rigidity o f tendon tissue. on overloading the cross link­ ages are the first to rupture and then the collagen fibres them­ selves. elastin fibres rupture last. if the overload is severe, all fibres will tear resulting in rup­ turing o f the tendon itself. if overloading is not as great, microscopic tearing o f the fibres will occur. repair in the mi­ crotorn tendon is poor largely due to the relative avascularity and low basal metabolic rate o f tendon tissue. this most likely accounts for the long duration symptoms in the area o f great­ est avascularity, eg. + / 5 cm above the heel in tendo-achilles tendinitis. the other site which is extremely common is the osseo-tendinous junction, eg. tennis elbow. this is most likely a functionally weak area 4 ------------------------------------sports medicine vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports injuries and is more liable to overload­ ing. with ageing tendon also undergoes a number o f bio­ mechanical changes and a sig­ nificant reduction in water content. it is interesting to note that similar changes occur in inactive tendon. it would ap­ pear that ageing and inactivity are inter-related and it also accounts for the significant in­ jury rate occurring in the age­ ing athlete who commences activity after a long period o f sedentary behaviour. sym ptom s m icrotearing pain is the most common symp­ tom wliich occurs usually on loading the tendon. in the early stages pain may occur at the be­ ginning o f activity but once the tendon inversion "warms up" pain often disappears. in the more severe cases no loading is possible owing to the severity o f the pain, eg. a player has to give up tennis. stiffness if the limb has been kept in one position for a long period of time, movement may be diffi­ cult owing to pain and stiffness but usually on movement the pain rapidly disappears. in chronic cases actual limitation o f joint movement may also be found. when pain occurs it will often radiate into the muscle which is loading the tendon, eg. down the forearm in tennis elbow and occasion­ ally even up the arm. signs two basic signs are important: • tenderness is present on palpation and may be ex­ tremely severe. • production o f pain on stressing the muscle at­ tached to the tendon. this stress test is positive in all cases o f tendinitis, eg. in tennis elbow this may be achieved by asking the patient to extend his elbow fully and to strongly dorsi flex his wrist. then by ap­ plying flexor pressure to the extended wrist, pain will occur in the region o f the elbow. the severity o f this pain is to a large extent dependent on the severity o f the degeneration o f tendinitis. in mild cases the patient will complain o f pain but will be able to withstand normal forces on the el­ bow. in cases with moder­ ate pain the wrist will gradu­ ally give way owing to the severity o f the pain. in severe cases, immediately thepatient will be unable to withstand the pressure exerted on the wrist. if rupturing has occurred a defect o f variable extent may be found in the ten­ don. in a total rupture marked weakness o f the muscle will be found and in the achilles tendon rupture, compression o f the calf muscle will not result in the normal movement o f the foot in the relaxed posi­ tion. in recent ruptures it may be difficult to palpate the defect owing to the amount o f swelling and bleeding and in chronic ruptures this may also be difficult owing to the scar tissue formation which has occurred between the ruptured area. how­ ever, marked weakness will still be the order o f the day. differential diagnosis pain may occur in tendons as a result o f friction between the tendon and its surrounding tis­ sue. in some areas where there is a distinct sheath, this is termed tenosynovitis. in other areas where there is no distinct sheath, paratendinitis occurs. the exact relationship between ten osyn ovitis/p araten din itis and tendon degeneration is not clear. in runners for example, paratendinitis is com m on without any form o f tendinitis being present either macro or microscopically. in some ar­ eas, eg. bicipital groove o f the humerus, tendon degeneration is often accompanied by a teno­ synovitis. this may even lead to rupturing o f the tendon pos­ sibly due to the damage o f its blood supply. treatm ent tendinitis is an extremely dif­ ficult condition ot treat. thus prevention is most important. loading must be progressive with overloading either acutely or chronically being avoided at all costs. strengthening exer­ cises may well be beneficial in avoiding these injuries. bi­ om echanical abnorm alities should be corrected eg. orthot ics o f anti-pronation shoes should be used in cases o f achilles tendinitis and tibialis posterior tendinitis. orthotics also appear to be helpful in cases o f patella tendinitis or if there is excessive patellar mobility in association with -------------------------------------------5 sportsgeneeskunde vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports injuries pronation. when injuries occur the principles are to treat the cause and to treat the result. thus the cause is by and large overload­ ing, a reduction o f the loading is extremely important. jar­ ring appears to be a major fea­ ture and therefore in severe cases all jarring should be avoided, eg. a runner should change to cycling while w ait­ ing for healing to take place. in the less severe cases reduction o f loading factors i.e. hill run­ ning and street running, should be done. loading may also be reduced by the use o f bi­ omechanical devices which take pressure o ff the damaged tendon while allowing the the financial operation of a surgery can be a headache of major proportions. and to keep things from falling apart you need more than a bookkeeper and a p.c. — with all the compromises inherent in generalised business software. you need a customised, single or multi-user system from noridata not just because its more cost-effective than ordinary p c ' s — but because its hardware and software are tailored specifically for your practice whether player to continue with sport, eg. tennis elbow guard which acts as a counterforce brace taking some o f the load off the tendon during loading activi­ ties such as tennis. in the severe cases, however, these do not appear to have any great value. elevation o f the heel in the case o f achilles tendinitis appears to similarly reduce the loading. treatment o f the results is extremely difficult as inflam­ mation plays a minor role in tendinitis. non-steroidal anti­ inflammatories do, however, appear to be effective espe­ cially in the minor cases. this would most likely be due to the analgesic properties. large or small — specialised prescribing or dispensing. supported by a nearby practice management professional who has a world of experience in integrating computers with the medical profession. computers that are compatible with other systems and expandable in the future without changing software. for the name of that practice management professional (we have over 50 country-wide) call us at (011) 484-4392 now. just a 15 minute no obligation demonstration will show you how easy it is to manage your practice painlessly. m edsdve south a frica's m ost used m edical practice m anagem ent system . .. . . . a n d w inner o f the c.s.a. i wo silver aw ard f o r an exceptional established s o u th a frican product. noridata division o f no ais ta n lim ited p o b o x 3 1 4 6 9 b r a a m f o n t e i n 2 0 1 7 physiotherapy also appears to be o f value in non-severe cases. the use o f steroidal anti-inflamm atories injected locally is controversial. it has been clearly shown that injec­ tion o f cortisone into tendon can cause degeneration o f ten­ don. it is thus important to avoid injections into the tendon but should cortisone be used, bathing the tendon appears to be beneficial. this can be as­ sured by feeling minimal pres­ sure when pushing on the plunger during injection into the region of the tendon. should it be difficult to push in the plunger this usually means that the needle is in the tendon and therefore would be stopped im­ mediately. a maximum o f three injections should be given. surgery should only be con­ sidered in cases that have been symptomatic for more than six months, if the symptoms are o f sufficient severity to warrant surgery. in cases o f rupture how­ ever, surgery still gives the best results. in the chronic case, surgery usually consists o f decompression o f the tendon by removing the paratendon and then multiple cuts in the lines o f the fibres o f the tendon to increase its blood supply, or in the case o f osseo-tendinous injury, a release o f the tendon from the bone provided no significant displacement occurs to that bleeding may also allow for more adequate scar tissue formation to occur with further adherence o f the tendon. in general, however, most o f these cases may take as long as four months before healing finally occurs. in less severe cases simple reduction o f activity is usually enough to allow heal­ ing to ultimately occur. □ let medsolve cure the biggest problem in practice management. 6 ------------------------------------sports medicine vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) c o panamor’ 25 emefic coaieo table! containing tbm cj d o o 'o n a r sodium l r r j reg no r 3 1 49 c o panamor' at* 5 0 e n te tr c o a t e d tablet c o n t a i n i n g 50niq i l d o t e n a c sodium l ± l reg no r'3 1/50 c o i panamor' 75 injection each 3ml' ampoule contains 75ma ilicloten.-ic s o o i u i t i with 4 l ! o v a b e n z y l alcohol as preservative l _ j req. no w/3 1/52 is y o u r p a tie n t b eing held p riso n er to p a in an d im m obility? t h ere is a re le a se ... non-steroidal anti-inflam m atory relieves pain reduces inflammat restores mobility reduces the cost o) trauma therapy available now in three panamor^ 25 tabl panamor^ at 50 t. and introducing panamor® 75 int£( release from inflammatory pain ’ ■ "• ' * 'pz «les, non( i ^ u) limited m tniiffnrafttt r » n itffinra in iiiiu r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) rugby dislocation of the cervical spine in a rugby player due to "crashing" of the scrum at scher in t r o d u c t io n the phase o f the game respon­ sible for the highest number of serious rugby injuries to the cervical spine and spinal cord is the scrum. in south a frica,1 new zealand2 and the united k ingdom ,3 scrumming is re­ sponsible for approximately 40% of these injuries. in a paper published in 19824 i re­ ported on players injured due to "crashing" o f the rugby scrum. d eliberate crashing of the two packs o f forwards is an illegal manoeuvre and should not be allowed to occur. the case history o f a school boy who sustained injury as a result o f this manoeuvre is p re­ sented to emphasize the dan­ gers o f the practice and illus­ trate the mechanism o f injury. c a se h is t o r y a 16 year old school boy play­ ing in a position o f hooker was in the process of binding with his two props prior to a scrum. the other pack o f forwards having already formed up rushed at them, catching them unawares. the hooker's head was caught in an awkward position and forcibly flexed. immediately afterwards, he developed weakness of the arms and legs and play was stopped. he was rushed to hospital, where examination revealed a quadriparesis at the c6 level with weakness o f the arms and legs. x-rays o f the cervical spine demonstrated anterior dislocation o f c6 and c7 with bilateral locking of facets. he was immediately taken to the­ atre where open reduction of the dislocation together with wiring and bone grafting was performed. this operation was done within 2 hours o f injury. postoperatively he began to regain muscle power and sen­ sation and made a good recov­ ery, having no residual defect 6 months after the injury. d isc u ssio n a t scher mbchb dmrd department o f radiology tygerberg hospital and uni­ versity o f stellenbosch po box 63 tygerberg 7505 the mechanism o f injury in this case as in other cases re­ ported, is flexion force. most cervical spinal injuries sus­ tained in the scrum are due to flexion force, whether as the result o f collapse o f the scrum or as in this case, crashing o f figure 1: a n te rio r dislocation o f c 6 and c7 w ith bilateral locking o f facets, sim ilar to the in ju ry de­ scribed in the case h is to ry (the original x -r a y is unobtainable). the scrum. the force or "impact weight" exerted as the packs meet is considerable and, if the front rows are not correctly posi­ tioned, a dangerous situation may arise. h odge5 has shown experimentally that the force exerted on impact is approxi­ mately 80% o f the maximum generated during the scrum­ mage. using an 8-man pack with a combined mass o f 727 kg the force recorded on impact was 746 kg. 8 ------------------------------------sports medicine vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) rugby deliberate crashing in an attempt to intimidate or un­ settle the opposing pack is a contravention o f the rules, as clearly stated in the laws of the game o f rugby football.6 law 20 deals with the scrum and reads: "it is dangerous play for a front row to form down some distance from its opponents and rush against them". prevention prevention o f the above inju­ ries depends on educating players to an awareness o f the dangers o f crashing, especially as serious cervical spinal injury is more prevalent in inexperi­ enced players. vigorous en­ forcement o f the rule quoted is of obvious importance. the referee should ensure that the ball is not put into the scrum until it is properly formed, with the front row players bound. it is encouraging to note that footnote 5, appended to law 20 which previously read7 “the referee has no authority to permit delay in putting in the ball be­ cause a player has not suc­ ceeded in getting his head down in the scrum m age’’, has been changed to footnote 10 in the most recent edition o f the laws of the game o f rugby f oot­ ball.6this footnote now reads, "in the interest o f safety, the referee has authority to perm it a delay in putting in the ball i f a player in thefront row has not succeeded in getting his head 4. down in the scrummage, but otherwise he should ensure that 5 . there is no delay a specific amendment o f the 6. rules which would remove this hazardous practice has been 7 . suggested.8 this is the adop­ tion o f the "staggered scrum" 8 in which the front rows o f each team first bind together and pack down. only then are the locks and loose forwards al­ lowed to join the scrum. the impact force is thus removed and the total impetus is less than that generated in conven­ tional rugby scrum. □ r e f e r e n c e s 1. s ch er a t . r u g b y injuries to the cervical spinal co rd . s a f r m e d j 1977; 51: 473 475. 2 . b urry h c , g ow land h. c e rv ical injury in football a n ew z ealand survey. br j s p o rts m e d 1981; 15: 56-60. 3 . w illiam s p and m ck ibbin b. unstable cervical spine in ju rie s in ru g b y a 20 y e a r rev iew . in ju ry 1987; 18(5): 329 332. s car a t . "c rash in g " the rugby scrum an avoidable cau se o f cervical spinal in ju ry . s a f r m e d j 1982; 6 1 : 919-920. h o d g e k. 1980. sp in a l injuries in ru g b y sc ru m s, p p 4 4 -4 8 . d u n ed in , new z ealan d : u niversity o f o tago. south a frican r u g b y b oard. 1988. the law s o f the g am e o f r u g b y football, c ape t o w n : sa r b . south a frican r u g b y b oard. 1988. the l aw s o f the g am e o f r u g b y f ootball, c a p e t o w n : sa r b . n o rto n t . 1980. the star, new zeal a n d , 14 ju ly , p8. spo rtsg eneesku nd e vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition iron status and athletic performance m ie k e f ab er functions of iron iron is an essential component o f the oxygen transportation c o m p o u n d s h a e m o g lo b in , myoglobin, and the cytochromes (w illiams, 1984) as well as various enzymes (steinbaugh, 1984). an iron deficiency can lead to impaired haemoglobin synthesis and a reduction in oxygen transport (o 'n eil et al, 1986). iron deficiency anemia iron deficiency may be ex­ plained by decreased iron ab­ sorption and increased iron loss (o 'n eil et al, 1986). iron can be lost through sweat losses, intestinal losses and haematuria. o ther causes for iron deficiency are increased demands for increased total body haemoglobin and poor dietary intake (ada report, 1987). iron deficiency can im pair physical perform ance, particumieke faber research institute fo r nutritional diseases, medical research council, tygerberg larly o f an aerobic nature (williams, 1984). iron deple­ tion without anemia can also affect physical perform ance (steinbaugh, 1984). such im ­ pairm ent can be manifested as a reduction in total exercise time, increased heart rate, decreased oxygen uptake, increased blood lactate concentrations and de­ creased work tolerance (o 'n eil et al, 1986). low serum iron, haemato crit and haemoglobin levels have been reported among athletes (o 'n eil et al, 1986) as well as low iron stores (ada report, 1987). women are more likely to become iron deficient as compared to men because o f a lower energy in­ take and because o f iron losses due to menstruation (williams, 1984). deficient iron stores result in weakness, fatigue, pallor, dyspnea on exercise, palpitations and prolonged restoration o f cardiorespiratory function to pre-exercise level (o ’neil et al, 1986). it has been recommended that female athletes take a multivitamin with iron to in­ sure an adequate intake. it is extremely unlikely for this amount o f iron to cause any side effects (vitousek, 1979). the american dietetic as­ sociation recommended that if an individuals iron intake re­ mains low after careful moni­ toring o f the diet, a moderate iron supplement, containing the 18 mg rda should be taken (ada report, 1987). since ascorbic acid enhances iron absorption, an iron supplement should be taken in conjunction with a source o f ascorbic acid (o ’neil et al, 1986). it is however recommended that plasm a ferritin levels be checked before supplementa­ tion is prescribed (ada re­ port, 1987). iron supplemen­ tation to individuals with iron deficiency anaemia will in­ crease perform ance capacity (w illiams, 1984). however, iron supplementation has no beneficial effect for an athlete with normal haemoglobin lev­ els (w illiams, 1984). large doses o f iron supplementation are o f no value to athletes, unless there is a measurable iron deficiency. large iron supplements may cause nau­ sea, gastric upset, constipation and accumulation o f iron in the tissues (vitousek, 1979). ex­ cessive iron intake can also inhibit the absorption o f zinc due to their similar physio c h e m ic a l c h a r a c te r is tic s (mcdonald and keen, 1988). sports anemia sports anemia or dilutional anemia results from an in10 spo rts m ed ic in e vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition crease in red blood cell mass and plasma volume. causes for sports anemia are adaptive response to maximise oxygen transport, haematuria, haemo­ lysis, iron loss through sweat­ ing, inhibition o f erythropoi esis, increase in blood volume, decreased iron absorption (o 'n eil e ta l, 1986), increased erythrocyte osmotic fragility, causing reduced red blood cell survival time and a possible shift in the oxygen dissociation curve (ada reports, 1987). sports anemia is both norm ocytic and normachromic (ada report, 1987). w hile some believe that marginal iron in­ takes may play a role in the de­ velopment in sports anemia (ada report, 1987), others believe that a deficient iron intake is not the cause since the haemoglobin levels does not respond to iron supplementa­ tion (vitousek, 1979). sport anemia is transitory (o 'n eil et al, 1986). endurance perform ­ ance is not impaired by sports anemia (o 'n eil et al, 1986). no specific treatment is re­ quired and iron supplementa­ tion is unnecessary (o 'n eil et al, 1986). food sources of iron organ meats, especially liver, are by far the best sources o f iron. o ther sources include meats, egg yolk, whole wheat, seafood, green leafy vegetables, nuts and legumes (williams, 1973). □ r e f e r e n c e s 1. a d a r e p o rts. p ositio n o f the a m erican d ietetic a ssociation: n utrition for p h y si­ cal fitness and athletic perfo rm an ce for adults. j am d ie t a sso c , 1987; 87: 933 939. 2 . m cd onald r , k een c l . iron, zinc and m agnesium nutrition and athletic p e rfo r­ m an ce. s p o rts m e d , 1988; 5 : 171-184. 3. o 'n e il f t , h y n ack h ankinson m t , g o rm an j. r esearch and application o f c u rre n t topics in sp o rts nutrition. j am d ie t a sso c , 1987; 8 6 : 1007-1012. 4 . steinbaugh m . n u tritio n al needs o f fe­ m ale athletes. clin sports m e d , 1984; 3: 6 4 9 -6 7 0 . 5 . v itousek s h . is m ore better? n u tr today n o v /d e c , 1979; 10-17. 6. w illiam s m h . v itam in and m ineral sup­ p lem ents to athletes: d o they help? clin s p o rts m ed , 1984; 3 : 6 2 3-637. 7. w illiam s sr . n u tritio n and diet th erap y , 2nd ed itio n . t h e c v m osby c om pany, saint l o u is, 1973, p i 44. ---------------------------------11 sportsgeneeskunde vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ] r elifen 500 ta b le ts 500 m g n a b u m e to n e . r eg. n o . r / 3 . 1 /265. n a b u m e to n e . s m ith k line b e e ch am p h a rm a c e u tic a ls p o box 347 b ergvlei 2012. w hen y o u r patient’s in pain, y o u r first responsibility is to take away that pain. q uickly. effectively. but doing so could lead to unacceptable gastro­ intestinal side effects and com bination therapy. but now , ten years of precisely targeted molecular research have produced a highly effective, non-acidic anti-inflam m atory. relifen. each tablet is made o f 500 mg nabum etone, a non-steroidal anti-inflamm atoi proven in num erous double blind studies to bt effective as other benchm ark n sa id s. yet its route of action is totally different. relifen is a non-acidic pro-drug. in the stom ach, it is relatively inactive. it is absorbed from the duodenum , into the portal blood sup finally, in the liver, it is metabolised into a pot inhibitor of prostaglandin synthesis. r efe r p a c k ag e in s e n fo r full p re s c r ib in g in f o r m a tio n . f u r th e r in fo rm a tio n is av a ilab le fro m o u r m cd ic al d e p a rtm e n t. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) relieving his pain is pretty sporting of you, old chap. but do you have to get him high on acid? the active metabolite penetrates the synovial luid to reach the inflamed site, giving effective relief rf symptoms. excretion is by the kidneys, so gastro ntestinal damage through biliary recirculation and ‘eflux is unlikely. for effective relief from pain and inflammation, vith less chance of gastro-intestinal discom fort, you low have an ideal choice. relifen. *kfcn an d th e sb lo g o a rc tra d e m a rk s . r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy update the physiotherapy management of chronic muscle tears of the calf in long distance runners the comrades m arothon is just around the com er and it is a good time to discuss the com ­ mon condition o f calf muscle tears. this injury is well docu­ mented by p ro f noakes in his book "lore o f running". usu­ ally a runner will give a history o f having increased his training o f both distance and speed. amazingly common is the fact that the veteran runner will confess he is wearing shoes which have lost heel height due to age. surely the micro trauma which develops in the calf muscle, must be aggrevatred by this loss o f heel height as the foot strikes the ground? the onset o f pain is gradual. the first stage is grade 1 where the pain is felt after the run and dis­ appears druing rest. grade 2 pain is felt at the beginning o f the run (as well as after the run) but disappears as the muscles warm -up. by the time the pain has reached grade 3, i.e. pain during the entire dura­ tion o f the run, the runner is no longer able to train. he either stops running for a short time hoping that the pain will disap­ pear with rest, o r he seeks help. rest, however, does not cure this problem. the muscle fibres run perpendicular and parallel to each other. if a micro tear develops and is continually traumatized, it will increase in size and heal with scar tissue. unfortunately as the runner continues to run, the tissue con­ tinues to become inflamed, more scar tissue is formed and the muscle fibres stick to­ gether. the muscle no longer functions biomechanically. on examination the physio­ therapist, palpating with her fingers, will find an exquisitely tender area in the muscle belly, surrounded by an area o f pro­ tective muscle spasm. the treatment for this injury is trans­ verse o r cross frictions. the physiotherapist massages the muscle fibres at right angles to their length, in order to sepa­ rate the muscle fibres, and achieves the result o f a small malleable scar which is no longer a problem. electrical modalities such as laser, inter­ ferential, ultrasound and pulsed shortwave diathermy are in­ cluded in the treatm ent in order 14 ------------------------------------sports medicine vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy update to decrease inflammation and prom ote healing. transverse frictions are only given every second day. they are extremely painful for the patient but are the key to the success o f the treatment. p h y sio th e ra p ists ad v ise runners on their shoes and future training methods. if necessary the runner is refer­ red to an orthotist for further advice. it is felt that one o f the reasons that the long distance runner has a tendency to re injure the original injury, is that there is a weakness in the muscle group. if the physio­ therapist has access to an iso­ kinetic testing machine, the run­ ner is not discharged until the muscles have been tested for strength and endurance com ­ paring left and right leg, as well as comparing the muscle bal­ ance between the plantarflex ors (primarily gastrocnemius and soleus) and the dorsiflex­ ors (primarily tibialis anterior). when the weakness has been identified, an exercise regime is given to the runner. this program m e should include isokinetic and isotonic exer­ cises for rapid results. finally the runner is taught the correct stretching methods. many runners feel that to stretch is to waste valuable running time. stretching, es­ pecially as one gets older and loses some o f o n e's youthful natural elasticity, is essential. the gastrocnem ius passes over the knee joint and the ankle joint, to stretch it, the knee is hyperextended and the foot is dorsiflexed. soleus on the other hand only passes over the ankle joint. to stretch it, the knee is flexed and the foot is dorsiflexed. stretching should take place after a 10 minute warm-up run. each muscle is slowly stretched for 30 seconds. as the inverse stretch reflex is activated, the muscle can be stretched slightly more for another 30 seconds. at the end o f the run, the runner is encouraged to warm down slowly and not to just stop running. in this way muscle soreness is avoided and muscles are being prepared for the next run. □ sasma news in this issue the position statement o f the south african sports medicine association is published. this opinion is underscribed by the medical association o f south africa, and is a milestone in the activi­ ties o f the sports medicine association insofar that it expresses the concern o f the health implications o f the use and abuse o f potentially harm ­ ful medications in the quest for better perform ance in sport. research done in south africa has shown a dramatic increase in the illegal use o f anabolic androgenic steroids by south african sportsm en.1 it may well be argued whether the authorities are doing enough to combat this evil, because world champion athletes called for strong action against offending athletes: "we consider doping to be the most shameful abuse o f the olympic ideal: we call for the life ban o f offending athletes, we call for the life ban o f coaches and the so-called doctors who administer this evil". (sebastian coe, olym­ pic congress at baden-baden, 1986). tydens die 4de sport geneeskunde kongres in sun city, was daar baie vrugbare samesprekings gevoer insake die gebruik van opkikkers in sport. gesien in die lig van suid-afrika se hertoetrede tot wereldsport, is dit belangrik dat daar 'n eenvormige beleid in ons land geform uleer moet word insake die hantering van hierdieneteligeprobleem . alle sp o rtlig g a m e m oet saam staan om 'n verenigde front te vorm om hierdie euwel te be stry tot voordeel van sport en die gesondheid en welsyn van ons sportlui. geneeshere, aptekers en afrigters moet in gelig wees insake die nadelige effekte wat die gebruik van opkikkers het op die moraal en ideaal van sport. persone wat anaboliese stero'iede voorsien aan sportlui, moet genadeloos gestraf word terwyl atlete wat hulle skuldig maak aan hierdie m isdryf die maksimum vonnis opgele moet word in 'n poging om ons sport te vry waar van hierdie euwel. die suid-afrikaanse sport geneeskunde vereniging doen 'n beroep op die sportge meenskap om kragte saam te snoer om ons huis in orde te kry sodat ons toegerus is op alle terreine om die uitdagings te aanvaar wat intemasionale kompetisies aan ons sportlui bied. ________________________________ 15 sportsgeneeskunde vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) conceptions/misconceptions in sports medicine types of muscle contraction as biomechanical concepts mc siff keywords: muscle contraction, isotonic, isometric, isokinetic, biomechanics. abstract the terms isotonic, isometric and isokinetic commonly used to describe different types o f muscle contraction are biomechanically inappropriate in most exercise situations. the less impressive terms 'static' and 'dynam ic' offer m ore accurate superordinate categories. the implications for isokinetic physiotherapy machines and rehabilitation are discussed. introduction several terms used in exercise science to refer to the different types o f muscle contraction are not applied with the level o f correctness they w arrant. among the most casual em ­ ployed are those beginning with the prefix iso-, namely isoki­ netic, isotonic and isometric. historically, they were invented to describe types o f contrac­ tion in which some property remains the same: velocity, tension or length. the consis­ tency o f these logical words led to their rapid acceptance, with m c s iff phd school o f m echanical engineering university o f the witwatersrand wits 2050 little criticism o f their precise meaning and scope ever taking place. it is the purpose o f this ar­ ticle to examine and redefine these terms with particular reference to their biomechani­ cal origins, so that their scope may be appreciated more thor­ oughly and they may be used with greater precision in de­ scribing muscular activity. in doing so, the advisability o f continuing to use these terms is considered. isokinetic terminology the term 'isokinetic' is encoun­ tered in two contexts: firstly, exercise physiology textbooks sometimes regard it as a spe­ cific type o f muscle contrac­ tion, and secondly, so-called isokinetic rehabilitation ma­ chines are often used by physiotherapitsts. use o f this term is dubious in both contexts, for reasons which become clear on exam ­ ining the fundamental bio­ m echanics describing this concept. isokinetics (iso 'sa m e ', kinetics 'velocity') literally means movement which occurs at constant velocity. if isokinetics is defined to be a specific form o f muscle contraction, along with static (is o m e tric ), and d ynam ic (concentric and eccentric) con­ traction, then it must be asked how isokinetic contraction, also a dynamic activity, differs from concentric and eccentric con­ traction . concentric refers to muscle contraction which brings the origin and insertion o f a muscle closer, or when muscle action produces a force which over­ comes the load being acted upon. f or this reason, soviet scientists use the term 'over­ coming' contraction or move­ ment. the term eccentric re­ fers to contraction which increases the distance between 16 ------------------------------------sports medicine vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) conceptions/misconceptions in sports medicine the origin and insertion o f a muscle, or, in other words, when the force o f contraction succumbs to the load. the soviets call this 'concessive' contraction. both o f these types o f contraction can occur at varying or constant velocity, so that it is difficult to classify isokinetic contraction as a to­ tally discrete form o f muscle contraction. this means that there can be isokinetic concentric action and isokinetic eccentric action. isokinetic muscle contraction is not a discrete entity. isoki­ netic action is merely a particu­ lar case o f dynamic action. the word 'action' has intentionally been chosen here, since dis­ tinction must be made between the external action and the internal contraction o f the muscle. what the textbooks in­ variably refer to is isokinetic action, or constant angular velocity, o f the moving limb, and not the biomechanical process within the muscle. it is impossible in the clinical or training setting to measure the contraction ve­ locity o f a muscle deep within the body, so that most labora­ to ry an aly sis o f m uscle contraction has been on biop sied muscle. even under these circumstances, contraction is usually elicited by electrical stim ulation under ex p eri­ mental conditions, so that it is generally invalid to discuss isokinetic contraction o f muscle during natural movement. isokinetic machines application o f the term 'isoki­ netic' to specific physiotherapy machines is beset with similar problems. by definition, it is biomechanically impossible to design a purely isokinetic m a­ chine. since isokinetic means 'constant velocity', then these machines must constrain the patient to move a limb at con­ stant velocity from beginning to end o f range o f the move­ ment. this is impossible, since the patient has to start his limb from rest and push against the machine until it can constrain the motion to approximately constant angular velocity. now, if any object moves from rest to any velocity, n ew ton's first two laws o f motion de­ cree that a force and an accel­ eration must be involved and the existence o f any accelera­ tion means that there can be no constant velocity. when the patient reaches the end o f the range o f movement, limb and machine arm stop mementar ily, then change direction. the presence o f any deceleration or change o f direction heralds the absence o f constant velocity. this implies that isokinetic action is not possible during initiation or termination o f any movement. thus, all isokinetic machines are able to produce approximately isokinetic action only over the middle o f the range o f movement. conse­ quently, these machines cannot offer realistic evaluation or therapy in the transition zones near the extremes o f the move­ ment range, regions where in­ juries commonly occur. therefore, there is no such entity as a true isokinetic m a­ chine. so-called isokinetic ma­ chines actually generate resis­ tance which is a function o f the applied muscle force. it would be more accurate for manufac­ turers to refer to their 'isoki­ netic' devices as semi-iso­ kinetic machines. it is unlikely that this will happen, so it is the responsibility o f physiother­ apists to appreciate the limita­ tion o f these machines when they use them therapeutically. one o f the very few occa­ sions when isokinetic action takes place is during isometric contraction. in this case, the velocity o f limb movement is constant and equal to zero. approximately isokinetic ac­ tion also occurs during mid­ range movement phases in swimming and aquarobics, with water resistance (which is pro­ portional to the square o f ve­ locity o f movement) serving to limit any increase in velocity. isotonic terminology the term isotonic, which means 'sam e to n e', should be limited or avoided under most circum ­ stances, since it is virtually im­ possible for muscle tension to remain constant while joint movement occurs over any ex­ tended range. constancy is possible only over a very small range under very slow or quasi­ isometric conditions o f move­ ment. naturally, constant tone also exists when a muscle is at rest, a state referred to as res­ ting tonus. w henever move­ ment occurs, muscle tension in c re a s e s o r d e c r e a s e s , particularly if acceleration is involved or one o f the stretch reflexes is activated. the w est germans and so­ viets prefer to use the term auxotonic, which refers to muscle contraction involving changes in muscle tension and length.2 other authors prefer to _________________________________ 17 sportsgeneeskunde vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) conceptions/misconceptions in sports medicine use the term allodynamic, from the greek 'alios' meaning 'other' o r 'not the s a m e '.1 the term 'dynam ic' is suffi­ ciently precise to describe the type o f contraction in question and should be used whenever the word isotonic is intended to mean any form o f dynamic, or non-isometric, contraction. the term isotonic should be reserved for the highly limited, short movement range situations where muscle tension definitely remains constant. isometric contraction even the concept o f isometrics is not as simple as it appears. isometric literally means 'sam e length', a state which occurs only in a muscle at rest. actu­ ally, it is not muscle length, but jo in t angle which remains con­ stant. contraction means 'shorte­ n in g ', so th at iso m e tric contraction, like all other forms o f muscle contraction, involves sliding o f actin and myosin muscle filaments relative to one another. isometric contraction may be defined more accurately by reserving it to mean muscle contraction which occurs when there is no external movement o r change in jo in t angle (or distance between origin and in­ sertion). the term isometric may be replaced by the simple word 'sta tic ', without sacrific­ ing any scientific rigour. furtherm ore, all isometric contractions are not the same. distinction may be drawn be­ tween rapid initiation and slow initiation isometric contractions, w here the form er refers to iso­ metric contraction occurring when a muscle contracts rapidly against an imposed load, and the latter refers to contraction produced gradually against a load. similarly, it is useful to recognise rapid termination and slow termination isometric contractions, which take into account the rate at which the load is withdrawn. recruit­ ment o f muscle tissue and the various stretch reflexes is different in all o f these cases, so it is important to be aware of these differences when iso­ metric rehabilitation or train­ ing is being considered. conclusion if the term isokinetic, isotonic and isometric are to be used to describe specific types o f muscle activity, then it is essential that the scope and limitations o f each term are appreciated, particularly since casual usage by exercise pro­ fessionals, gymnasium users and equipment manufacturers has led to human movement and physical conditioning being explained and analysed in a bi omechanically inaccurate man­ ner. although the term static and dynamic may lack the more authoritative tone o f the iso prefixed words, they offer the average exercise scientist and fitness professional adequate replacements for isometric and isotonic, respectively. isoki­ netic activity may then be regarded as a special case o f dynamic activity in which the resistance is a function o f the applied muscle force. □ r e f e r e n c e s 1. b erger r a . a p p lied e xercise p hysio­ logy. lea & f eb ig er, philadelphia 1982: 9. 2. v erkhoshansky y. f undam entals o j special strength training in s p o rt fizkul lurai sports pub lishers, m oscow 1977. (s3) v/3.1/62, v/3 .1/238 w .f .i. h/34/128 tilcotil® c o m p o n e n ts : tenoxicam 20 mg indications: s y m p to m a tic treatm en t of the fo llo w in g painful in fla m m a to ry and d egenera tive d is o rd e rs of the m u scu loskeletal s yste m : rh e u m atoid a rth ritis ; o s te o a rth ritis ; a n k ylo s in g s p o n d y litis ; e xtra a rtic u la r d is o rd e rs , e .g . te n din itis , b u rs itis , p e ria rth ritis , g o u ty a rth ritis (fo r ta b le ts). dosage: 20 m g once d a ily at the sam e tim e each d a y. the parenteral fo rm is used fo r one o r tw o d a ys. for treatm en t in itiation in acute g o u ty a rth ritis 40 m g (2 tab lets) once daily fo r tw o d a ys fo llo w e d b y 20 m g once d a ily fo r a fu rth e r five days is re co m m e n d e d . c o n tra-in d icatio n s: k n ow n h yp e rs e n s itiv ity to the d r u g . p atients in w h o m sa licyla tes or oth er n o n ste ro id a l an ti­ in fla m m a to ry d ru g s (n s a id s ) induce s y m p to m s of asthm a, rh in itis o r urticaria . patients w h o are s u ffe rin g o r have suffered fro m severe diseases of the upper g a s tro in te s tin a l tra ct, in clu d in g g a s tritis , g a s tric and duodenal ulcer. b efore an aesthesia o r s u rg e ry , ‘t i l c o t i l ’ should not be g iven to patients at risk of kidn ey failu re, o r to patients w ith increased risk of bleedin g. c o n c u rre n t treatm en t w ith s a licyla te s o r oth er n s a id s s hould be avoid ed . p re g n a n c y and lactation. p recautions: s im u lta n e o u s treatm en t w ith a n tico a g u la n ts and/or oral an tid ia betics s h o u ld be avoided unless the patient can be c lo s e ly m o n ito re d . renal fu n c tio n (b u n , creatinine, d e ve lo p m e n t of oedem a, w e ig h t g ain , e tc .) s h o u ld be m o n ito re d , w hen g iv in g a n s a id to the e lde rly o r to patients w ith c o n d itio n s that could increase th eir risk of d e ve lo p in g renal failure. packs: t a b le ts 20 m g : 10 's , 3 0 ’s. vial pack co n ta in in g 1 vial active substan ce and 1 am p ou le w a te r fo r in je ctio n . 18 -----------------------------------sports medicine vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) vita-thion com bats fatig u e replenishes energy energy for the family 2 sachets in half a glass of water at breakfast for 30 days. ® reg/no. m/33/250: eutherapy. division of servier laboratories s.a. (pty) ltd. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) drugs in focus spare your joints sport trauma is a common event. painful joints and muscles and tendons must surely be regarded as an "early warning signal" that all is not well in the musculoskeletal or locomotor systems. the pain, and the often associated tenderness and swelling, are intended by n a­ ture to slow us down, to urge us to take recuperative measures, to "go quiet" for a sufficient period to allow for the rees­ tablishment o f full physio­ logical and functional integrity. pow erful pain relievers available powerful painkillers are avail­ able, and the indiscriminate use of such analgesics is a real con­ cern in sport medicine. why? because such analgesics may mask the warning signals so effectively, that excessive ac­ tivity is resumed before healing has had sufficient time to oc­ cur. non-steroidal anti-inflammatory analgesics the non-steroidal anti-inflam ­ matory analgesics (nsaias) are very widely used to provide pain relief in the event o f sport injuries. these medicines in­ terfere with the biochemical and cellular components o f the inflam m atory response to trauma. the damage is the stimulus that evokes the in­ flammation and pain, and these nsaias interfere with the chemical mediators o f the in­ flammation and the pain. inflammation good and bad while it is true that the inflam­ matory response if too enthu­ siastic, may itself promote dam age, yet it must be regarded as part o f the healing process. thus, suppression o f the inflammatory response is likely to suppress or delay healing, and because the pain relief if often very notable, physical activity is recom ­ menced prematurely. joints particularly at risk w hile the repercussions o f such premature physical activity may not be too significant for soft tissue injury, it is con­ sidered to be highly significant for joints where permanent and recurrent damage may be produced. the messages should be clear * pain, swelling, tenderness, inflammation in the mus­ culoskeletal system is a signal to "go slow". • nsaias are often excel­ lent pain relievers, that also suppress components o f the inflammatory response. nsaias can provide an en­ tirely false sense o f recov­ ery, and so permit prem a­ ture return to full physical activity. » joints in particular, need time to recover from in­ ju ry , otherwise cumulative permanent damage may accrue. • circumspect use o f these nsaias by well informed persons hold few dangers in terms o f damage to joints and soft tissues of locomotion. • be sensible be kind to your joints. note: the non-steroidal anti-in­ fla m m a to ry a n a lg e s ic s (nsaias), constitute all those medicines which function in a manner akin to aspirin to reduce pain, fever and inflam­ mation. nsaias currently available in rsa include preparations that contain any one o f the following: aspirin, azapropazone, bumadi-zone, diclo-fe nac, diflunisal, feno-pro fen, fenbufen, flurbip­ rofen, ibuprofen, in dometchacin, ketopro­ fe n , m e c lo fe n a m a te , mefenamic acid, nabume tone, naproxen, oxap rozin, oxyphenbutazone, phenylbutazone, piroxi cam, sulindac, tenoxicam, tiaprofenic acid, tolmetin.n 20 spo rts m ed ic in e vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) abstracts abstracts from the clinical journal of sports medicine the official journal of the canadian academ y of sports medicine injury profiles in w heelchair athletes: results o f a retro­ spective survey dar m cc orm ack, dc reid, rd s teadw ard and dg syro tu ik d epartm ent of physical education and sports s tud­ ies, d epartm ent of a th le tic s , and the glen sather sports m edicine clinic, u n iversity of a lberta, edm onton, a lberta, canada little is known about the nature and m echanism o f sports injuries among wheelchair athletes. the purpose o f this study was to develop an injury profile for this group. a total o f 90 wheelchair athletes were surveyed retrospectively by means of a questionnaire. three hundred and forty-six injuries were reported in 18 different sports, 107 (30,9% ) o f which occurred in basketball, 106 (30,6% ) in track, and 42 (12,1% ) in road racing. eighty percent o f the athletes were competitive, with 60% com­ peting at a national level. most o f the athletes trained 6-10 h/week. injuries to the soft tissue o f the upper extremities were most common, with the hand involved 21,3% and the shoulder 16,7% o f the time. blisters and abrasions accoun­ ted for 47,7% o f the injuries. all o f the athletes surveyed sustained injuries, yet little protective gear was worn except for gloves (60%). in view o f the potentially serious long-term complications of some o f these injuries, and the corresponding impact o f the ability o f these athletes to carry out their functions of daily living, prompt diagnosis and treatm ent are m andatory. despite this, less than one-third (30,8% ) o f all wheelchair ath­ letes sought medical assistance for their sports injuries. key words: w heelchair sports disabled sports spinal cord injury. clin j sport m ed 1991; 1(1): 35-40. muscle rq and lactate ac­ cumulation from analysis of the vc02-v02 relationship during exercise w illiam l beaver and karlman w asserm an, division of res­ piratory and critical care physi­ ology and m edicine, d epart­ m ent of m edicine, harbor ijcla medical centre, ucla school of m edicine, torrance, c alifornia, usa. we analyzed the vc02-v02 rela­ tionship derived from 1 min incremental (15 w /min) exer­ cise tests o f 10 normal subjects. the curve was quite linear below the anaerobic threshold (at). we deduce that the slope must equal the respiratory quotient (rq) o f the exercising muscles, with a mean value for these subjects o f 0,97 -f /-0,06, indicating that the metabolic substrate is essentially glyco­ gen. beyond the at, respira­ tory c 0 2 output rises at a faster a rate above as compared to below the at, reflecting the rate o f h c 0 3 buffering of lactic acid. projecting the straight line o f vc02 versus vq2 below the at into the region beyond the at provides an es­ timate o f the vc02 due to con­ tinuing aerobic metabolism. the difference between the actual vc02 and the aerobically produced vc02 (excess vc02) describes the rate o f c 0 2 gen­ erated from h c 0 3 buffering o f lactic acid. the integrated excess c 0 2, corrected for any hyperventilation, provides a measure o f the quantity of h c 0 3 depletion and thus lac­ tate accumulation. since our measurements are non-steady state, a dynamic simulation model o f total lactate accumu­ lation and arterial lactate con­ centration, based on excess c 0 2 output and compartmental blood flows and volumes, was developed and found to predict experimental results o f lactate concentration increase. thus, the excess c 0 2 output can be a useful measure o f lactate accu­ mulation and, with the devel­ oped model, serve to describe -----------------------------------------21 sportgeneeskunde vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a t t r a c t the rise in arterial lactate con­ centration during a progres­ sively increasing work rate test. key words: c 0 2 production excess c 0 2 lactate accumu­ lation lactate concentration model lactate threshold muscle "rq". clin j sport m ed 1991; 1(1): 27-34. clinical evaluation o f shoul­ der instability richard j hawkins, md, and nicholas gh mohtadi, md, department of orthopaedic surgery, university of eastern ontario and university hospi­ tal, london, ontario, canada; and university of calgary sport medicine centre, calgary, a l­ berta. the shoulder is the most un­ stable joint in the body. pa­ tients with shoulder instability may present in a variety o f ways, ranging from subtle com­ plaints o f pain including the "dead arm syndrome", to those with subjective instability, ap­ prehension, or even those who can voluntarily demonstrate a dislocation. instability can be classified according to the on­ set (traumatic, atraumatic, over­ use), the direction (anterior, posterior, multidirectional), the timing or frequency (acute or recurrent), the degree o f insta­ bility (subluxation or disloca­ tion), and whether it occurs voluntarily or not. the physi­ cal examination should be di­ rected toward ruling out other problems and determining whether generalized ligamen­ tous laxity is present. specifi­ cally, the stability assessment includes apprehension tests, the relocation test, or fowler's sign and an estimation o f gle­ nohumeral translation. the use o f a local anaesthetic injection into the subacromial space can be very helpful in guiding the physical examination. an ac­ curate diagnosis o f shoulder in­ stability can usually be made on a clinical basis by utilizing the information outlined in this report. key words: appre­ hension tests glenohumeral translation relocation tests. clin j sports m ed 1991; 1(1): 59-64. isokinetic evaluation of quad­ r ic e p s a n d h a m str in g symmetry following anterior cruciate ligament reconstruc­ tion. harter ra, osternig lr, stan difer lw. a rch phys med rehabil 1990; 71: 465-8. isokinetic muscle parameters are commonly measured after anterior cruciate ligament (acl) reconstruction to deter­ mine the dynamic status o f the knee as well as monitor prog­ ress in rehabilitation. in this study, the symmetry o f the quad­ riceps and hamstrings muscu­ lature in postsurgical and con­ tralateral normal limbs o f sub­ jects who had undergone one o f two types o f acl reconstruc­ tion was evaluated. in addition, subjects were evaluated for differences on selected isoki­ netic parameters between types o f surgery and lengths o f postoperative periods. forty six subjects aged 18 to 49 years (mean, 2 3.7 years) postsurgi­ cal and normal contralateral limbs were divided into groups according to type of autogenous intraarticular acl substitute and length o f postoperative period. from the results o f paired tests and analyses o f variance it was evident that significant asymmetries be­ tween limbs for all measures o f quadriceps and hamstrings musculature strength and en­ durance existed (p < 0.001) ir­ respective o f the type o f recon­ struction technique. average surgical knee deficits in ham­ strings endurance were sig­ nificantly less for the long-term (41 to 101 months) follow-up group (1.9%) than for the in­ termediate (24 to 40 months) group (12.1% ). it would seem that extended periods o f time are required to approximate hamstrings endurance symme­ try after acl reconstruction. in these subjects, assymmetries between postsurgical and con­ tralateral normal limbs may re­ flect either incomplete reha­ bilitation or an inability to regain full isokinetic strength and endurance following acl reconstruction. have you subscribed to sports medicine? see page 24 for more details. 22 ___________________ sports medicine vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) anabolic steroids masa takes stand against dispensing of anabolic steroids masa has come out strongly against the dispensing o f ana­ bolic steroids, warning the profession it considers making these drugs available to the public for non-medical reasons in a serious light. at present the biggest di­ lemma faced by doctors is that there is little indisputable evi­ dence concerning the effect o f high dosage or extended usage o f anabolic steroids on athletes' health, as research with high dosages o f these substances is not permissible. however, the south african sports medicine association (sasma), a special interest group o f m asa, is o f the opin­ ion based on a comprehensive literature survey and a careful analysis o f the claims concern­ ing the psysiological, physical and psychological effects and adverse effects o f anabolic androgenic steroids that their potential medical use is limited and can be replaced with safer and more effective drugs. sasma believes that the medical supervision o f sports­ men should primarily be di­ rected to clinical diagnosis and treatment o f patients to restore normal health and function rather than to scientific meth­ ods or to enhancement o f per­ formance. the association has formu­ lated a position statement on the use and abuse o f anabolic steroids, which has been adopted by masa as official policy on the issue and includes the following recommendations: • serious and continuing ef­ forts should be made to educate athletes, coaches, trainers, physicians, par­ ents, physical educators and the general public re­ garding the limited bene­ fits and potential risks o f steroid use as documented by scientific research. • all sports governing bod­ ies (including the body building association) must uniformly reject the use o f anabolic-androgenic ster­ oids on the basis o f ethics and the ideals o f fair play o f competition and because their use gives possible competitive advantages harmful to the user. • a national drug testing programme should be in­ stituted by all sport gov­ erning bodies to be a deter­ rent to steroid usage and testing should equally encompass all levels o f sportsmen. for this reason an accredited laboratory should be appointed to conduct the testing and the testing procedures should be standarised throughout the country. • consideration should be given to re-evaluating the medical use and indication for the anabolic-andro­ genic steroids, by the medicines control coun­ cil in view o f rescheduling or even banning these drugs for medical or non-medical reasons. there is currently no method for predicting which individu­ als are more likely to develop adverse effects, some o f which are potentially hazardous. • doctors should not be al­ lowed to prescribe these drugs in non-pharmaco logical doses to obviously healthy athletes with the sole intention o f increasing in an artifical and unfair manner their performance in competition. • pharmacists, veterinarians, pharmacological companies and other suppliers should be strongly discouraged and prohibited to supply any sportsman or sports club with anabolic steroids with­ out a valid prescription. should instances come to light where athletes were illegally supplied with these potentially harmful drugs, the necessary disciplinary steps should be taken. • doping control in south africa for all national sport­ ing bodies should be co­ ordinated and standardised by an independent body with medical, scientific and sport representation to comply with international standards and the rules o f the international olympic committee medical com­ mission. □ ----------------------------------------- 23 sportsgeneeskunde vol. 6 no. 2 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) affirikaaese spoirtgeinieeslkminide '̂v eff ©mgmg a s p e c ia lis l g r o u p o f th e m a s a ( in c o r p o r a t e d a s s o c ia t io n not fo r g a in ) 'n s p e s ia l e g r o e p v a n d ie m v s a ( i n g e ly f d e v e r e n ig in g so n d e r w in s b e ja g ) po box 13206 clubview 0014 m ay 1991 dear doctor, the characteristic that distinguishes a professional from an educated person is the professional person’s desire and responsibility to stay abreast of the developments of his or her field of expertise. the halflife of our professional knowledge is about 3 years, and for this reason it is vitally.important to continuously refresh and supplement our knowledge. sports medicine, the official mouthpiece of the sa sports medicine association, has over the years become a treasured source of knowledge for the health care professional in the sports medicine arena. the journal features not only original research papers and articles by leading specialists in sports medicine, but also current news and relevant abstracts. the publishing of sports medicine has been taken over by medpharm publications. the journal will be published quarterly namely, february, may, august and november. due to the present rate of inflation sasma are no longer able to distribute sports medicine free of charge and have reluctantly introduced a subscription fee of r20.00 per annum (members of sasma will continue to receive the publication free of charge). in addition to managing costs, this will enable the editorial board maintain a high quality editorial content and render a more effective service to you, the health care professional. your subscription to sports medicine is an investment in your future and the future of the health care profession. we count on your continued support. regards, clive noble editor sports medicine name: .. address: code: ................................................................. tel: ................................................................. enclosed please find my cheque/postal order payable to sasma for: ® r30 for full membership* to sasma (this includes receiving sports medicine free of charge) ® r25 for associate membership** to sasma (this includes receiving sports medicine free of charge) • r25 for student membership*** to sasma (this includes receiving sports medicine free of charge • r20 + gst (r22,60) for subscription to sports medicine note * full membership: medical practitioner who is a member of masa ** associate membership: members of supplementary health service professions, registered with the samdc and who are members of their own professional associations *** student membership: medical students who are in their clinical years r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) original research 1 sajsm vol. 32 no. 1 2020 creative commons attribution 4.0 (cc by 4.0) international license epidemiology of injuries among u18, u19, u21 and senior elite netball players cj sinclair, 1 phd; ff coetzee, 1 phd; r schall, 2 phd 1 department of exercise and sports sciences, faculty of health sciences, university of the free state, bloemfontein, south africa 2 department of mathematical statistics and actuarial science, faculty of natural and agricultural sciences, university of the free state, bloemfontein, south africa corresponding author: c j sinclair (jonescj@ufs.ac.za) netball is a dynamic and physically demanding sport involving high-intensity movements, such as jumping, breaking/stopping, lunging and leaping, interspersed by periods of low-intensity movements, such as walking, standing and passing the ball. the combination of highand low-intensity movements can predispose players to lower limb injuries, as the demands on athletes are physically and mentally challenging.[1,2] studies have indicated that the most frequently injured joints in netball are the ankle and knee, of ligamentous or musculoskeletal anatomical origin.[1–5] furthermore, hopper reported that the prevalence of lower limb and back injuries might account for 23% of injuries in netball players.[4] previous researchers have studied possible risk factors for injury, such as hypermobility of joints and somatotyping.[2– 4,6,7] other factors, such as poor landing techniques, fast rotational movements and contact with other players, could also be regarded as predisposing factors for injuries.[5,6] a study by pillay and frantz[8] concluded that the lack of a warm-up before a game, training for four or more hours a week, and being injury-free within the past 12 months decreased the risk of injury. coetzee et al.[9] found that the playing surface has an impact on injury, for example, cement surfaces accounted for 80% of knee injuries as opposed to 20% on synthetic surfaces. the majority (89%) of serious injuries occurred on cement surfaces.[9] however, limited data on netball injuries in south africa is available, and only at senior level or during match play at a specific tournament.[1,8] data on the epidemiology of injuries can contribute to the development of programmes for the prevention of injuries. in this study, the injuries recorded were those received during the preseason, practice and match play during two consecutive seasons in four different age categories (u18a high school league, u19, u21 and senior) in the free state (fs), south africa. detailed information on the incidence of injuries by age group, player position, anatomical site and time of play was collected. to these authors’ knowledge, this is the first such study in south africa on the epidemiology of injuries in netball players in four age groups. therefore, the objective of this study was to determine the epidemiology of injuries in u18, u19, u21 and senior fs netball players. specifically, the study was conducted to report data on the following aspects of injuries in netball players:  the incidence of injuries by age group;  the number and proportion of injuries by player position, namely goal attack (ga), wing attack (wa), goal defence (gd), goal shooter (gs), centre (c), wing defence (wd) and goalkeeper (gk), as well as the number and proportion of injuries by anatomical site in the various age groups;  the type of injuries in the various age groups;  the number and proportion of injuries during play times (match versus practice injury, and the playing quarter for match injuries) per age group. methods a cross-sectional, descriptive study was conducted to determine the epidemiology of injuries among u18a league secondary school players, u19, u21 and senior netball players in the free state during the 2017 and 2018 seasons. the total study population consisted of 96 players (u19, u21 and senior n=12 each, and n=60 u18a league secondary school players). an injury was defined as any physical complaint sustained by a player during or following a netball game or practice that required medical treatment, associated with either loss of time or performance restriction.[10] an injury questionnaire was used to collect data on the nature of all injuries during the study period. the questionnaire was based on the consensus background: despite a substantial body of literature on injuries among elite netball players in south africa, no study reports on the timing and type of injuries and the reason for injuries. objective: to determine the epidemiology of injuries in u18, u19, u21 and senior netball players in the free state (fs), south africa, over two consecutive netball seasons (2017/2018). methods: an injury questionnaire was used to collect data on 96 eligible players. results: a total of 48 injuries were reported. the profile of injuries revealed that 58% (n=28) of the injuries occurred during matches, 29% (n=14) during practice and 13% (n=6) during preseason training. acute injuries accounted for 54% (n=26) of the total, while 46% (n=22) were overuse injuries. a third of all the injuries were re-injuries. the centre (c) position had the highest incidence of injuries in players (n=14; 29%). the ankle was the most frequently injured body part (n=18; 36%), followed by the lower leg and achilles tendon (n=6; 13%) thus largely the ligaments and muscles. the overall incidence rate of injuries during match play was 33.9 injuries per 1 000 hours of match play. conclusion: preventative strategies should consist of ankle and lower leg strengthening and neuromuscular balance techniques. the focus should be on correct landing techniques, results of abrupt change of direction movements and short bursts of speed. keywords: incidence, sport high performance, injury profile s afr j sports med 2020;32:1-6. doi: 10.17159/2078-516x/2020/v32i1a7577 mailto:jonescj@ufs.ac.za http://dx.doi.org/10.17159/2078-516x/2020/v32i1a7577 https://orcid.org/0000-0002-0393-3100 https://orcid.org/0000-0002-4145-3685 https://orcid.org/0000-0002-3652-3976 original research sajsm vol. 32 no. 1 2020 2 statement on injury definitions in rugby union[10] and adapted for netball.[1] when an injury was sustained, it was diagnosed by a medical doctor. all players from all teams were approached weekly as a group to determine who had sustained an injury the previous week and attained a medical diagnosis. after the player signed the informed consent form, a research assistant helped the player to complete the questionnaire pertaining to the injury. when players played more than one position, the player’s position was recorded based on the position they were playing at the time of the injury data analyses were done using sas version 9.4 (sas institute inc., cary, nc). the number and percentage of injuries were determined with regard to their timing (during a match, preseason, practice), type (acute/trauma, overuse, reinjury), how the injury was sustained (possible contact with a player), per player position, per anatomical site of injury, and severity of injury. injuries were categorised as follows: slight (0 days absent), minor (1–7 days absent), moderate (8–28 days absent) or major (more than 28 days absent). the injury incidence rate was calculated as the number of injuries per 1 000 playing hours, where a playing hour refers to an individual playing for one hour (thus a match lasting one hour represents 14 playing hours for the two participating teams). the study was approved by the health sciences research ethics committee (hsrec) of the university of the free state (ufshsd 2017/0014). permission was obtained from the south african netball association and fs netball, and the fs department of education, the headmasters of secondary schools participating in the u18a netball league, netball coaches and finally, parents if the player was younger than 18 years of age, and the players themselves. results profile of injuries a total of 48 injuries were reported of which eight were senior players, five u21, six u19 and twenty-nine u18a players. table 1 indicates the overall profile of injuries as the number of injuries per age group. in addition, in this study, 16 (33%) injuries were re-injuries and 22 (46%) overuse injuries. furthermore, the timing and nature of the injuries and how the injuries occurred are summarised. injuries by player position table 2 presents the injuries by player position and age group, and overall by player position. overall, the c 14 (29%) sustained most injuries, followed by the ga 12 (25%) and wd 9 (19%), with the gk 1 (2%) having the lowest incidence of injuries. anatomical site of injuries table 3 presents the number and percentage of injuries per anatomical site by age group and overall. overall, the most frequently occurring injuries involved the ankle joint (n=18; 38%), followed by injuries to the lower leg and achilles area, face and/or head (n=6; 13%), groin injuries, (n=5; 10%), and injuries to the knee (n=4; 8%). type of injuries table 4 presents the type of injuries by age group. the most common injuries were ligament tears/strains (n=17; 36%). concussion and fractures were recorded only in the u18a group (n=3 each; 6%). table 1. overall number of injuries by age group for the 2017/2018 netball seasons age group injury profile senior u21 u19 u18a total n (%) n (%) n (%) n (%) n (%) total number of injuries 8 5 6 29 48 when injury occurred match play 5 (63) 4 (80) 5 (83) 14 (48) 28 (58) preseason 1 (13) 1 (20) 0 (0) 4 (14) 6 (13) practice session 2 (25) 0 (0) 1 (17) 11 (38) 14 (29) nature of injury acute 5 (63) 3 (60) 5 (83) 13 (45) 26 (54) overuse 3 (38) 2 (40) 1 (17) 16 (55) 22 (46) re-injury (acute or overuse) 3 (38) 2 (40) 2 (33) 9 (31) 16 (33) how injury occurred contact 6 (75) 5 (100) 4 (67) 9 (31) 24 (50) non-contact 2 (25) 0 (0) 2 (33) 20 (69) 24 (50) table 2. injuries by player position age group player position* senior u21 u19 u18a total n (%) n (%) n (%) n (%) n (%) total number of injuries 8 5 6 29 48 goal attack (ga) 2 (25) 1 (20) 3 (50) 6 (21) 12 (25) wing attack (wa) 2 (25) 0 (0) 0 (0) 2 (7) 4 (8) goal defence (gd) 1 (13) 0 (0) 1 (17) 0 (0) 2 (4) goal shooter (gs) 1 (13) 0 (0) 1 (17) 4 (14) 6 (13) centre (c) 2 (25) 0 (0) 0 (0) 12 (41) 14 (29) wing defence (wd) 0 (0) 4 (80) 1 (17) 4 (14) 9 (19) goalkeeper (gk) 0 (0) 0 (0) 0 (0) 1 (3) 1 (2) *some players play more than one position, but player positions were recorded according to the position they were playing at the time of the injury. original research 3 sajsm vol. 32 no. 1 2020 time of injury table 5 summarises the timing of injuries; for match injuries the number per quarter is presented. furthermore, the number of preseason injuries and the number of injuries that occurred during a practice session are reported. of the 48 injuries, 32 (67%) were match injuries, of which four was sustained in a practice match. approximately two-thirds of match injuries overall were sustained during the second and third quarters of the match (21 out of 32 match injuries, 67%). twenty out of the 48 injuries (42%) occurred during practice sessions, preseason or in a practice match. severity of injury table 6 displays the severity of injuries by age group and overall. overall, five (11%) were slight, 12 (26%) minor, 19 (40%) moderate, and 11 (23%) were major injuries. injury incidence per 1000 player hours table 7 summarises the number of matches played by each age group, the percentage of injuries that occurred during match play, the total number of playing hours and the incidence of injuries during match play per 1 000 hours. the highest incidence of injuries was observed in the u19 age group (79.4 injuries per 1 000 hours). table 3. anatomical site of injuries age group site senior u21 u19 u18a total n (%) n (%) n (%) n (%) n (%) total number of injuries 8 5 6 29 48 ankle 4 (50) 4 (80) 2 (33) 8 (36) 18 (38) lower leg/achilles region 0 (0) 0 (0) 0 (0) 6 (21) 6 (13) face and/or head 0 (0) 0 (0) 0 (0) 6 (21) 6 (13) groin 1 (13) 0 (0) 1 (17) 3 (10) 5 (10) knee 1 (13) 0 (0) 0 (0) 3 (10) 4 (8) lower back 0 (0) 0 (0) 2 (33) 1 (3) 3 (6) feet and/or toes 0 (0) 1 (20) 0 (0) 1 (3) 2 (4) forearm and/or wrist 0 (0) 0 (0) 0 (0) 2 (7) 2 (4) shoulder and/or clavicle 1 (13) 0 (0) 1 (17) 0 (0) 2 (4) hip 1 (13) 0 (0) 0 (0) 0 (0) 1 (2) posterior thigh 0 (0) 0 (0) 0 (0) 1 (3) 1 (2) table 4. type of injuries sustained age group type of injury senior u21 u19 u18a total n (%) n (%) n (%) n (%) n (%) total number of injuries 7* 5 6 29 48 concussion 0 (0) 0 (0) 0 (0) 3 (10) 3 (6) fracture 0 (0) 0 (0) 0 (0) 3 (10) 3 (6) haematoma/bruising 0 (0) 0 (0) 0 (0) 1 (4) 1 (2) ligament strain/tear 3 (43) 3 (60.0) 2 (33) 9 (31) 17 (36) meniscus/cartilage 1 (43) 0 (0) 0 (0) 0 (0) 1 (2) muscle strain/tear/cramp 0 (0) 1 (20.0) 1 (17) 5 (17) 7 (15) muscular tendon injury 1 (43) 0 (0) 0 (0) 1 (2) other bone injury 0 (0) 0 (0) 0 (0) 4 (14) 4 (9) other injury 0 (0) 1 (20.0) 2 (33) 4 (14) 7 (15) tendon tear/tendinopathy 1 (14.3) 0 (0) 0 (0) 0 (0) 1 (2) tendon tear/tendinopathy & other injury 1 (14.3) 0 (0) 1 (17) 0 (0) 2 (4) *the type of injury was not recorded for one player in the senior group. table 5. time of injury (match or practice) age group time senior u21 u19 u18a total match practice match practice match practice match practice match practice n (%) n (%) n (%) n (%) n (%) n (%) n (%) n (%) n (%) n (%) preseason period 0 (0) 1 (13) 0 (0) 1 (20) 0 (0) 0 (0) 0 (0) 4 (14) 0 (0) 6 (13) practice session 0 (0) 2 (25) 0 (0) 0 (0) 0 (0) 1 (17) 0 (0) 7 (25) 0 (0) 10 (21) match play 1st quarter 1 (13) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 3 (10) 1 (2) 3 (6) 2nd quarter 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 10 (35) 0 (0) 10 (21) 0 (0) 3rd quarter 2 (25) 0 (0) 4 (80) 0 (0) 1 (17) 0 (0) 4 (14) 1 (4) 10 (21) 1 (2) 4th quarter 2 (25) 0 (0) 0 (0) 0 (0) 4 (67) 0 (0) 0 (0) 0 (0) 6 (13) 0 (0) total number of injuries 5 (63) 3 (38) 4 (80) 1 (20) 5 (83) 1 (17) 14 (49) 15 (53) 28 (58) 20 (42) original research sajsm vol. 32 no. 1 2020 4 discussion profile of injuries the objective of this study was to determine the epidemiology of injuries in u18, u19, u21 and senior fs netball players by reporting detailed data on the incidence of injuries by age group, player position, anatomical site and time of play. the study included four age groups of players and recorded injuries over two consecutive seasons, including injuries sustained during practice and preseason training. these findings can be compared with relevant research in south africa,[1,2,8] on the epidemiology of injuries; however, existing studies focused on senior participants, either at a specific tournament, one specific age group, or over a single competitive netball season. a number of international studies evaluated injury incidence, mechanism of injury, incidence by player position and severity of injury for an entire netball season or at a specific netball tournament.[5,11–14] in this study of netball players in the fs u18a high school league, u19, u21 and senior players, an overall injury incidence rate of 33.9 injuries per 1 000 playing hours for match injuries was reported (table 7). this is similar to the incidence rate reported by langeveld et al.[1] which was 501 injuries per 1 000 hours of match play, or 35.8 injuries per 1000 playing hours. botha reported an injury rate of 22.5 injuries per 1000 playing hours in u15 and u16 school children in south africa.[15] injuries can be attributed to many factors, such as incorrect landing, slipping, tripping and direct trauma.[11] in this study, 26 injuries (54%) occurred due to trauma of some kind. furthermore, 24 of the 48 injuries with relevant information (50%) resulted from contact with another player. this proportion of contact injuries is notably high when considering the rules of netball, as contact is prohibited, and a penalty is (or should be) awarded to and/or a warning issued to the opponent in such cases. however, in the present study, the detailed causes or presumed causes of injuries, such as landing incorrectly, slipping and tripping, were not recorded. mcmanus et al.[11] found that 38% of injuries to the knee and ankle could be attributed to incorrect landing techniques. furthermore, mcmanus et al. [11] found that slipping, tripping and landing incorrectly while moving forward were the main causes of injuries, although they did not consider contact with another player as a reason for injury. similarly, pillay and frantz[8] in their study on south african netball players found that 19% of injuries at the knee region and 29% to the ankle could be attributed to incorrect landing techniques. ellapen et al.[2] investigated non-elite netball players in kwazulu-natal (kzn) and obtained similar results, with incorrect landing techniques contributing to 63% of ankle injuries and 57% of knee injuries. they did, however, consider contact with another player as a reason for injury, but this accounted for only 21% of all of the injuries in their study.[2] additionally, in the present study, injuries were recorded by body segment and which body region (left, right or bilateral) was injured. the right side had 25 (52%) injuries compared to 12 (26%) on the left side. this is similar to findings by langeveld et al.[1] who found that ankle/foot injuries occurred on the right side 59% of the time compared to 41% on the left side. knee injuries occurred on the right side 53% of the time and 47% on the left side.[1] in this present study a total of 11 (23%) bilateral injuries were observed, which could be attributed to overuse injuries to the lower leg, such as medial tibial stress syndrome, or to the lower back such as muscle spasms and triggers. in certain sports, the dominant leg may be at increased risk of injury because it is preferentially used for kicking, pushing off, jumping, or landing. however, the association between limb dominance and injury is controversial.[18] one found that left-leg dominant athletes were more likely to sustain an ankle injury. another study reported that the dominant leg sustained more non-contact knee injuries and one found an increased incidence of ankle injuries on the dominant side, while three other studies reported no association between limb dominance and injury. therefore, the relationship between limb dominance and injury remains unclear.[18] injuries by player position this present study’s data (table 2) show that the c, ga and wd have the highest risk of injuries, while the gk has the lowest. this is similar to the findings of smith et al.,[7] who reported that ga, wa and gd suffered the most injuries and gk the least. table 6. severity of injuries age group severity senior u21 u19 u18a total n (%) n (%) n (%) n (%) n (%) total number of injuries 7* 5 6 29 48 slight (0 days absent) 0 (0) 0 (0) 1 (17) 4 (14) 5 (11) minor (1–7 days absent) 2 (29) 2 (40) 2 (33) 6 (21) 12 (26) moderate (8–28 days absent) 4 (57) 3 (60) 2 (33) 10 (35) 19 (40) major (≥ 29 days absent) 1 (14) 0 (0) 1 (17) 9 (31) 11 (24) *severity of the injury was not recorded for one player in the senior group table 7. number of matches played and rate of incidence of injuries per 1 000 hours age group variable senior u21 u19 u18a total total number of injuries 8 5 6 29 48 number of matches played 34 18 9 57 118 injuries sustained during match play 5 (63*) 3 (60*) 5 (83*) 17 (59*) 30 (63*) total playing hours (h) 238 126 63 399 826 incidence rate (during match play; per 1 000 h) 21.0 31.7 79.4 35.1 33.9 *percentage of total number of injuries original research 5 sajsm vol. 32 no. 1 2020 similarly, hopper et al.[6] found that the wa, c and gs had an increased incidence of injury, while the gk showed minimal risk. in contrast, mcmanus et al.[11] reported that defensive injuries (22.8% by either the gk or gd) were more likely to occur than any other injuries elsewhere on the court. the higher risk of injury for the c, ga and wd found in this present study can possibly be explained by the higher physical demands on these players during match play. anatomical site and type of injuries regarding the anatomical site of injuries (tables 3 and 4), the overall occurrence was 18 (36%) ankle injuries, followed by six injuries (13%) to the lower leg and achilles area. previous research also reported a high incidence of ankle and, contrary to the present study, knee injuries.[1,2,5–7] of the 22 (46%) overuse injuries (table 1), six injuries were to the lower leg and achilles area, which were mainly bilateral and affected overloaded areas. the most prevalent types of injuries were ligament and muscle strains. this finding was in agreement with the results reported from a number of other studies.[1,2,5–7] time of play when the injury occurred of the 48 injuries reported in the study (table 5), 30 (63%) occurred during matches, while 20 (42%) took place during either the preseason (n=6; 13%) or practice (n=14; 29%). of the 28 match injuries, the majority occurred either in the second (n=10; 36%) or the third quarter (n=10; 36%) of matches. information on the time of injury might indicate whether an injury could be attributed to fatigue during the match, lack of conditioning in the preseason, or incorrect warmup techniques during the practice session. only one south african study reported in the literature indicated time of play when the injury occurred with similar results to this study’s findings.[1] no literature could be found on studies reporting injuries in the preseason or during practice, as in the present study. severity of injuries most injuries (table 6) were either minor (n=12; 26%) or moderate (n=19; 40%). this is similar to findings by mcmanus et al. [11] who found that 43% of injuries were grade 2 moderate injuries and 44% were grade 1 minor injuries. on the contrary, according to the classification of injuries used by langeveld et al. [1] the majority of injuries to the ankle joint (42%) were classified as severe (7 days absent). however, the majority (71%) of all injuries in that study were otherwise minor, as the player could return to play by the next game.[1] in the present study, injuries where the player could return to play by the next game were classified as minor injuries, due to the short absence from the game. practical application this study provided data on the epidemiology of injuries in senior, u21, u19 and u18a elite netball players in the free state by age group, player position, anatomical site, type, time of play and severity of the injury. based on these results and data from the literature, attention should be directed at training modalities that include neuromuscular control and complex training to improve the correct landing techniques during explosive movements,[14,16] in order to prevent injuries sustained during netball. additionally, short bursts of speed with quick stop-and-go movements, combined with agility and quick change of direction while moving forward, is relative to maximal strength training.[17] strength and conditioning coaches can use these findings to develop specific conditioning programmes. conclusion precautionary measures should target, in particular, the prevention of ankle and knee joint injuries. the inclusion of prehabilitation exercise programmes as part of conditioning at the start of the season may decrease the rate of acute injuries. additionally, the education of coaches with regard to periodisation of the netball training season and the design of netball conditioning programmes are needed to reduce the relatively high number of overuse injuries found in this study. the limitations of this study include the small sample size, the use of a questionnaire, which means there could have been underreporting of injuries or inaccurate reporting of the type of injury. discrepancies were found in the rate of injuries reported in the literature due to different methods of data collection, different definitions of an injury and the interpretation thereof. furthermore, different netball populations and level of play make comparisons difficult. conflict of interest and source of funding: the authors declare that they have no conflict of interest and no source of funding. acknowledgements: dr. daleen struwig, medical writer/editor, faculty of health science, university of the free state, for technical and editorial preparation of the manuscript. author contributions: cj sinclair contributed to the planning and execution of the study, collected the data and wrote the draft article. ff coetzee initiated the study, contributed to its planning and collaborated on writing the article. r schall contributed to the planning of the study, performed the statistical analysis of the data and collaborated on the writing of the article. references 1. langeveld e, coetzee ff, holtzhausen lj. epidemiology of injuries in elite south african netball players. s afr j res sport phys educ recreation 2012; 34(2):83–93. 2. ellapen tj, schoeman kt, zaca lt , et al. prevalence of musculoskeletal injuries among adolescent recreational netballers in kwa-zulu natal, south africa. british journal of medicine and medical research 2015; 9(3):1–5. article no. bjmmr. 16966. [doi.org/10.9734/bjmmr/2015/16966] 3. hopper d. a survey of netball injuries and conditions related to these injuries. aust j physiother 1986; 32(4):231–239. [doi.org/10.1016/s0004-9514(14)60656-5] 4. hopper dm. somatotype in high performance female netball players may influence player position and the incidence of lower limb and back injuries. br j sports med 1997; 31(3):197– original research sajsm vol. 32 no. 1 2020 6 199. [doi.org/10.1136/bjsm.31.3.197] [pmcid:pmc1332516] 5. mcmillan jt, mclaughlin p, nicholls b. an epidemiology of injuries in sub-elite netball during a competitive season: a club perspective [coursework master's thesis]. melbourne: victoria university, 2004. http://vuir.vu.edu.au/848/ (accessed 18 october 2019). 6. hopper d, elliott b, lalor j. a descriptive epidemiology of netball injuries during competition: a five-year study. br j sports med 1995; 29(4):223–228. [doi.org/10.1136/ bjsm.29.4.223][pmid:8808533] 7. smith r, damodaran ak, swaminathan s, et al. hypermobility and sports injuries in junior netball players. br j sports med 2005; 39(9):628–631. [doi.org/10.1136/ bjsm.2004.015271] [pmcid:pmc1725309] 8. pillay t, frantz jm. injury prevalence of netball players in south africa: the need for injury prevention. s afr j physiother 2012; 68(3):7–10. [doi.org/10.4102/sajp.v68i3.17] 9. coetzee d, langeveld e, holtzhausen l. training habits, training surface and injuries among south african netball players. s afr j res sport phys educ recreation 2014; 36(3):39–49. 10. fuller cw, molloy mg, bagate c, et al. consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union. br j sports med 2007; 41(5):328–331. [doi.org/10.1136/bjsm.2006.033282] [pmid:17513907] 11. mcmanus a, stevenson mr, finch cf. incidence and risk factors for injury in non-elite netball. j sci med sport 2006; 9(1-2):119–124. [doi.org/10.1016/j.jsams.2006.03.005] [pmid:16621712] 12. partner r, upsall s, francis p. injury epidemiology in female netball players during the 2016/2017 season in the united kingdom. grad j sport exerc phys educ res 2018; 9(1):7. http://eprints.leedsbeckett.ac.uk/5136/ (accessed 18 october 2019). 13. hume pa, steele jr. a preliminary investigation of injury prevention strategies in netball: are players heeding the advice? j sci med sport 2000; 3(4):406–-413. [doi.org/10.1016/s14402440(00)80007-9] [pmid:11235006] 14. hopper aj, haff ee, joyce c, et al. neuromuscular training improves lower extremity biomechanics associated with knee injury during landing in 11-13 year old female netball athletes: randomised control study. front physiol 2017; 8:883. [doi.org/10.3389/fphys.2017.00883] 15. botha c. the epidemiology of injuries in junior netball players in south africa. master's dissertation. bloemfontein: university of the free state; 2018. https://scholar.ufs.ac.za/bitstream/ handle/11660/10045/bothac.pdf?sequence=1&isallowed=y (accessed 4 april 2020). 16. humphrys br, aspe, r, clarke r, hughes jd. the effects of complex training on neuromuscular development of the lower limbs in youth netball players. j athl enhanc 2018;7(5). https://www.scitechnol.com/peer-review/the-effects-of-complextraining-on-neuromuscular-development-of-the-lower-limbs-inyouth-netball-players-y8re.php?article_id=8252 (accessed 18 october 2019). 17. thomas c, comfort p, jones pa, dos'santos t. strength and conditioning for netball: a needs analysis and training recommendations. strength cond j 2017; 39(4):10–21. [doi.org/10.1519/ssc.0000000000000287] 18. murphy df, connolly da, beynnon bd. risk factors for lower extremity injury: a review of the literature. br j sports med 2003;37(1):13–29. [doi.org/10.1136/bjsm.37.1.13] [pmid: 12547736] http://vuir.vu.edu.au/848/ http://eprints.leedsbeckett.ac.uk/5136/ file:///c:/users/yvonne/documents/sasma%20journal%20assaf/doi.org/10.3389/fphys.2017.00883 https://scholar.ufs.ac.za/bitstream/%20handle/11660/10045/bothac.pdf?sequence=1&isallowed=y https://scholar.ufs.ac.za/bitstream/%20handle/11660/10045/bothac.pdf?sequence=1&isallowed=y https://www.scitechnol.com/peer-review/the-effects-of-complex-training-on-neuromuscular-development-of-the-lower-limbs-in-youth-netball-players-y8re.php?article_id=8252 https://www.scitechnol.com/peer-review/the-effects-of-complex-training-on-neuromuscular-development-of-the-lower-limbs-in-youth-netball-players-y8re.php?article_id=8252 https://www.scitechnol.com/peer-review/the-effects-of-complex-training-on-neuromuscular-development-of-the-lower-limbs-in-youth-netball-players-y8re.php?article_id=8252 file:///c:/users/yvonne/documents/sasma%20journal%20assaf/doi.org/10.1136/bjsm.37.1.13 original research 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license tackle injury epidemiology and performance in rugby league – narrative synthesis n burger,1 phd, b jones,1,3,4,5,6 phd, s hendricks,1,3 phd 1 division of exercise science and sports medicine, department of human biology, university of cape town, rondebosch, south africa 2 department of public & occupational health and the emgo institute for health and care research, vu university medical center, amsterdam, the netherlands 3 carnegie applied rugby research (carr) centre, carnegie school of sport, leeds beckett university, leeds, uk 4 leeds rhinos rugby league club, leeds, uk 5 england performance unit, the rugby football league, leeds, uk 6 school of science and technology, university of new england, nsw, australia corresponding author: n burger (nicholas.burger@uct.ac.za) rugby league (rl) is an intermittent, highintensity, collision-based team sport.[1–3] during a typical match, played over the course of 60-80 minutes and depending on the level of play, players physically engage each other to compete for ball possession and territory.[4] this dynamic and physical contest is known as the tackle and can occur up to 700 times during a match.[2] as such, the ability to repeatedly engage in the tackle, whether as a ball carrier or tackler, is essential for team success and player performance.[5] it is also the leading cause of injury, with over 90% of total injuries occurring during the tackle in some professional and amateur cohorts.[6,7] to effectively reduce the risk of injury and optimise performance, following a sport injury prevention or sport performance process model such as the translating research into injury prevention practice (tripp) model[8] (involving six stages) or the applied research model for the sport sciences (armss)[9] (involving eight stages), is recommended. these models outline a sequence of stages that need to be completed to ensure the uptake and sustainability of an injury prevention or performance initiative in the ‘real world’.[8] in these models, the first stage proposes establishing the extent of the ‘problem’ through injury surveillance or descriptive performance studies. the second stage aims to understand why and how injuries or performances occur, that is, identifying injury risk factors and performance determinants. the third stage seeks to develop potential preventive and performance enhancing measures for testing in ideal or controlled conditions (stage four). stage five aims to understand the implementation context and the final stage (stage six) monitors the effectiveness of the preventive and performance measure in the real world. the first stage is essential to these injury prevention and performance process models, as it provides direction and focus to the subsequent stages. a large proportion of rl injury and performance research falls within the first stage of the sequence. this has also shown to be the case in rugby union research.[10] literature reviews aim to search and synthesise this body of research with the goal of pushing forward the injury prevention and performance agenda, and to inform practice and coaching. while general epidemiology and performance reviews for rl have been conducted,[4,11] a review specifically synthesising tackle injury epidemiology and tackle frequencies by playing levels, competition, and by role (ball carrier or tackler) has not been published. therefore, to fulfil the first stage of tripp and aarms, the purpose of this narrative synthesis was to systematically search and synthesise tackle injury epidemiology and tackle performance frequencies in rl. methods search strategy a search was conducted for publications that reported tacklespecific factors in rl (rugby union and sevens were included in the search and analysed separately)[10] according to systematic review guidelines.[12,13] three electronic databases (pubmed, scopus and web of science) were searched using the keyword combinations ‘rugby’ and ‘contact’, ‘rugby’ and ‘tackle’, and ‘rugby’ and ‘league’ and ‘injur*’. eligibility criteria the search was limited to english-only articles published background: in rugby league (rl), the ability to repeatedly engage in the tackle, whether as a ball carrier or tackler, is essential for team success and player performance. it is also the leading cause of injury, with over 90% of total injuries occurring during the tackle in professional and amateur cohorts. to effectively reduce the risk of injury and optimise performance, establishing the extent of the ‘problem’, through injury surveillance or descriptive performance studies is required. objective: the purpose of this narrative synthesis was to systematically search and synthesise tackle injury epidemiology and tackle performance frequency in rl. to achieve this objective, a systematic review was conducted. methods: the search was limited to english-only articles published between january 1995 and october 2018. based on the search criteria, a total of 53 studies were found: 32 focused on tackle injury epidemiology (nine cases studies) and 21 focused on tackle frequency. results: in general, over 600 tackles may occur during an rl match. tackle injury frequencies (both overall and time-loss injuries) ranged between 47%-94% at the professional level, and between 38%-96% for the lower levels of play. a greater proportion of injuries occurring in professional rl are severe time-loss injuries when compared to lower levels of play. most time-loss and overall injuries occur to players who are tackled, i.e., ball carriers, across all levels of play. conclusion: this narrative synthesis will facilitate tackle injury prevention and performance research in rl, and act as a reference document for coaches and practitioners. keywords: tackler, ball carrier, injury prevention, aetiology, tackling s afr j sports med 2021;33:1-8. doi: 10.17159/2078-516x/2021/v33i1a9313 http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9313 https://orcid.org/0000-0002-0010-9212 https://orcid.org/0000-0002-3416-6266 https://orcid.org/0000-0002-4274-6236 original research sajsm vol. 33 no. 1 2021 2 between january 1995 and october 2018. articles that involved quantitative data on rl (including all ages and levels of play, and male and female players) were included. only studies that included tackle-related match and/or training data (pertaining to tacklers, and/or ball carriers) specific to (1) injury epidemiology and (2) tackle performance frequencies were selected for inclusion. the included studies clearly defined and included the tackle or ball carrying as part of their analysis and did not group these aspects of play into general contact/collision data thus rendering them indistinguishable from other contact phases. rates for overall and time-loss tackle injuries (only studies reporting number of injuries per 1000 hours of exposure) and tackle-related injury frequencies (percentages) were tabulated (tables 1-2). a time-loss injury is defined as an injury that resulted in a player being absent from normal match/training/recreational activities for seven days more (this definition was used in all studies reported in the current analysis but may differ for other studies) after the incident. medical attention injuries are injuries that required treatment from a healthcare professional but resulted in no time away from normal activities. overall injuries include both medical attention and timeloss injuries events. injury case studies specific to tackle events were also reviewed (see appendix in the supplementary material). overall tackle numbers and rates (only studies reporting total number of tackles per match, and/or number of tackles per game or per minute) were tabulated (table 3) and included in the current study. narrative literature reviews, systematic reviews, meta-analyses, editorials, journal letters, book chapters, conference proceedings, discussions and qualitative research studies were excluded from the analysis. all other quantitative study types and case studies were accepted for review. screening process a five-step approach was followed to identify the final group of articles that would eventually be included in the final review (figure 1). two authors (nb and sh) independently screened the titles using the eligibility criteria specified. the reliability of the authors was assessed by comparing the results of the titlescreening process. disparities in the results were discussed and resolved by the authors. nb continued the screening process of the abstracts and full-text articles. the articles were excluded at each step if they met the exclusion criteria or did not meet the inclusion criteria. data interpretation only key findings (relating to tackle events) from each study were presented in this review. confidence intervals (95% cis) fig. 1. summary of the literature screening process. #, manuscripts included in rl analysis; ##, manuscripts included in rl appendix; *, manuscripts included in separate rugby union and sevens analysis/appendix; **, rl manuscripts included in the current study only. original research 3 sajsm vol. 33 no. 1 2021 and standard deviations (±sds) were provided in the tables (depending on availability). all values were rounded off to a maximum of two decimal places, where necessary. results the overall and time-loss injury frequencies and rates for professional rl are shown in table 1 and all other levels in table 2. other rl tackle injury-related research also focused on specific types of injuries including concussion,[14–20] spinal and neck injuries,[21] and shoulder injuries.[22] tackle injury case-studies were also found and are summarised (see appendix in the supplementary material). the overall number of tackles per match and tackle rates (tackles per game or per minute) for all levels of play are shown in table 3. successful and unsuccessful tackles were grouped together. discussion the aim of this narrative synthesis was to systematically search for tackle injury and tackle frequency performance studies in rl and synthesise these with the goal of facilitating tackle injury prevention and performance research. this can be regarded as a reference document for coaches and practitioners. based on the search criteria, a total of 53 studies were found: 32 focused on tackle injury epidemiology (with a further nine cases studies) and 21 focused on tackle frequency. in general, over 600 tackles may occur during a rl match. each forward executes between 20-25 tackles, which is double that of backs. in contrast, forwards and backs carry the ball into the tackle, i.e. being tackled, at similar frequencies. a major challenge with the current body of literature on tackle frequencies in rl is the lack of or inconsistencies in defining the tackle. studies have either used the definition of the tackle based on rl law, when the ball carrier is held by one or more of the opposing players, and either the ball or hand of the arm holding the ball makes contact with the ground, or the ball carrier cannot make any further progress, or it is used as a definition where ‘attempted’ tackles are included. to improve the consistency and quality of tackle research in rl, a set of clear descriptions and definitions need to be developed and agreed upon, similar to those used in rugby union.[56] tackle injury frequencies (both overall and time-loss injuries) ranged between 47%-94% at the professional level and between 38%-96% for the lower levels of play. up to 73% of time-loss injuries, i.e. more severe injuries resulting in the player being absent from matches or training sessions taking place at least one week after the initial injury event, occurred during the tackle at the professional level.[24] this frequency was lower at the amateur level, with up to 61% of time-loss injuries occurring during tackles.[31] also, the majority of time-loss and overall injuries occur to the tackled player (i.e. the ball carrier) in professional rl (63%) and across all other levels (61%). king et al.[6] reported a high overall tackle-related injury incidence in a national rugby league cohort (300 injuries per 1000 hours). this rate is substantially higher than the other figures reported in professional rl which were estimated at around 77.4 injuries per 1000 hours.[26] however, overall injury rates are substantially higher in semi-professional cohorts, reaching up to 382.2 injuries per 1000 hours,[32] and are even greater in amateur rl, with one study reporting incidences as high as 541 injuries per 1000 hours.[39] it is worth noting that the majority of injury studies were conducted on single teams, which may explain why injury frequencies and incidences varied between studies. although there were no explicit variations in the methods used to collect injury data across the studies, the differences in incidence rates may also be attributed to table 1. tackle-related injury frequencies and rates in professional rugby league study cohort injury definition injury frequency injury rate gissane et al., 1998[23] european super league time-loss (>7 days) 70% (35% tackled, 35% tackling) 35.2/1000 hours (17.6/1000 hours tackled; 17.6/1000 hours tackling) gissane et al., 2003[24] european super league time-loss (>7 days) 73% (50% tackled, 23% tackling) 43.8/1000 hours (30.1/1000 hours tackled [95%ci 23.737.8]; 13.7/1000 hours tackling [95%ci 9.5-19.1]) gissane et al., 2003[25] european super league overall and timeloss (>1 day) 74% (44% tackled, 30% tackling) n/a gabbett et al., 2012[26] national rugby league overall and timeloss (>1 day) n/a 77.4/1000 hours (30/1000 hours tackled [95%ci 22.639.7]; 47.4/1000 hours tackling [95%ci 38.0-59.1]) georgeson et al., 2012[27] national rugby league overall and timeloss (>1 day) 49% (41% tackled, 8% tackling) n/a king et al., 2012[6] national rugby league overall and timeloss (>7 days) 94% (50% tackled, 44% tackling) 300/1000 hours (95%ci 265-340) sanctuary et al., 2012[28] european super league overall and timeloss (>1 day) 72% n/a ullah et al., 2014[29] national rugby league overall and timeloss (>1 day) 47% n/a n/a, this data is not available for the study original research sajsm vol. 33 no. 1 2021 4 discrepancies in the levels of efficiency between the individual data capturers, although this cannot be confirmed. this narrative synthesis was limited to the first stage of the tripp and aarms models. as such, rl studies that are tackle-related but did not meet the criteria were excluded. for example, studies that focused on describing the types of tackles,[2,48] tackle technique,[5,57–62] or the physiological and physical loads associated with the tackle,[43,47,48,51,52] were not included in the current review. arguably, these studies relate to why and how injuries occur or what is required to succeed in the tackle, which fulfils the objectives of the second stage in the tripp and aarms models, i.e. identifying injury risk factors and performance determinants. while an analysis of all tackle injury risk factors and performance determinants in rl was beyond the scope of the current synthesis, this paper forms the basis for such a review. table 2. tackle-related injury frequencies and rates in semi-professional, amateur and youth rugby league study cohort injury definition injury frequency injury rate babic et al., 2001[30] croatian-slovenian amateur rugby league overall and timeloss (>1 day) 55% (25% tackled, 30% tackling) n/a gabbett, 2001[31] second division amateur rugby league time-loss (>7 days) 61% (35% tackled, 26% tackling) 22.8/1000 hours (95%ci 12.0-33.7) gabbett, 2003[32] australian semiprofessional rugby league overall and timeloss (>1 day) 46% 382.2/1000 hours (95%ci 355.5-408.9) gabbett, 2004[33] australian semiprofessional rugby league overall and timeloss (>1 day) 38% (22% tackled, 16% tackling) 350.2/1000 hours (202.2/1000 hours tackled [95%ci 174.8-229.7]; 148.0/1000 hours tackling [95%ci 124.5-171.6]) gabbett, 2005[34] australian semiprofessional rugby league time-loss (>7 days) 53% 36.0/1000 hours (19.0/1000 hours tackled [95%ci 13.0–24.0]; 17.0/1000 hours tackling [95%ci 11.0–23.0]) gabbett, 2005[35] sub-elite rugby league (*unlimited interchange) time-loss (>7 days) n/a 37.4/1000 hours (19.8/1000 hours tackled [95%ci 12.3-27.2]; 17.6/1000 hours tackling [95%ci 10.5-24.6]) gabbett, 2005[35] sub-elite rugby league (*limited interchange) time-loss (>7 days) n/a 37.5/1000 hours (24.0/1000 hours tackled [95%ci 12.2-35.7]; 13.5/1000 hours tackling [95%ci 4.7-22.3]) gabbett and domrow, 2005[36] australian semiprofessional rugby league time-loss (>7 days) 54% (30% tackled, 24% tackling) 29.7/1000 hours (16.5/1000 hours tackled [95%ci 12.1-20.9]; 13.2/1000 hours tackling [95%ci 9.3-17.1]) king et al., 2006[37] new zealand semiprofessional rugby league overall and timeloss (>1 day) 66% (43% tackled, 23% tackling) 242.7/1000 hours (158.3/1000 hours tackled [95%ci 78.2-238.4]; 84.4/1000 hours tackling [95%ci 25.9-142.9]) king et al., 2006[37] new zealand amateur rugby league amateur overall and timeloss (>1 day) 68% (44% tackled, 24% tackling) 483.1/1000 hours (310.6/1000 hours tackled [95%ci 167.1-454.0]; 172.5/1000 hours tackling [95%ci 65.6-279.5]) gabbett, 2008[38] under-19 rugby league time-loss (>7 days) n/a 29.3/1000 hours (19.2/1000 hours tackled [95%ci 11.0-27.5]; 10.1/1000 hours tackling [95%ci 4.1-16.0]) king et al., 2009[39] division 1 premier grade amateur rugby league overall and timeloss (>1 day) 86% (overall) (48% tackled, 37% tackling); 87% (time-loss) (51% tackled, 36% tackling) 228.1/1000 hours (overall) (128.5/1000 hours tackled [95%ci 103.2-160.0]; 99.6/1000 hours tackling [95%ci 77.7-127.8]); 54.6/1000 hours (time-loss) (32.1/1000 hours tackled [95%ci 20.7-49.8]; 22.5/1000 hours tackling [95%ci 13.3-38.0]) king et al., 2009[39] division 2 premier grade amateur rugby league overall and timeloss (>1 day) 77% (overall) (58% tackled, 19% tackling); 71% (time-loss) (44% tackled, 27% tackling) 541.0/1000 hours (overall) (404.9/1000 hours tackled [95%ci 338.3-484.5]; 136.1/1000 hours tackling [95%ci 99.8-185.5]); 153.1/1000 hours (time-loss) (95.3/1000 hours tackled [95%ci 65.8-138.0]; 57.8/1000 hours tackling [95%ci 36.0-93.0]) king et al., 2010[7] premier division amateur rugby league overall and timeloss (>1 day) 96% (68% tackled, 28% tackling) 501.3/1000 hours (356.7/1000 hours tackled [95%ci 258.4-492.3]; 144.6/1000 hours tackling [95%ci 87.2-239.8]) orr and cheng, 2016[40] elite australian junior rugby league overall and timeloss (>1 day) 61% (overall) (36% tackled, 25% tackling); 66% (time-loss) (42% tackled, 24% tackling) n/a n/a, this data is not available for the study original research 5 sajsm vol. 33 no. 1 2021 table 3. tackle numbers and rates in rugby league (all levels of play) study cohort rate definition tackle rate sirotic et al., 2009[41] national rugby league tackling/minute 0.25 (sd±0.16) (1st half: 0.26 [sd±0.18]; 2nd half: 0.23 [sd±0.16]) sirotic et al., 2009[41] semi-professional new south wales premier league tackling/minute 0.28 (sd±0.16) (1st half: 0.30 [sd±0.17]; 2nd half: 0.27 [sd±0.16]) king et al., 2010[2] elite rugby league (international, nrl, national youth competition) total match tackles (tackling and tackled) tackling/game tackled/game 701 (sd±64)a 32 (sd±15)b 21 (sd±4)c gabbett et al., 2011[42] national rugby league total match tackling attempts tackling/game 265.1 (sd±214.1)a 17.1 (sd±9.1)b mclellan et al., 2011[43] national rugby league tackling/game tackled/game 14.9 (sd±10.5)a (forwards: 20.1 [sd±11.3]; backs: 10.7 [sd±8.0]) 10.2 (sd±3.8)b (forwards: 10.9 [sd±4.2]; backs: 9.7 [sd±3.5]) sirotic et al., 2011[44] national rugby league tackling/minute backs: 0.12 (sd±0.09); forwards: 0.41 (sd±0.07); fullbacks: 0.05 (sd±0.02); hookers: 0.34 (sd±0.11) service: 0.31 (sd±0.12) sykes et al., 2011[45] english super league and national rugby league tackling/minute tackled/minute 1st quarter: 0.28 (sd±0.21)a; 0.14 (sd±0.10)b 2nd quarter: 0.28 (sd±0.27)a; 0.13 (sd±0.12)b 3rd quarter: 0.26 (sd±0.22)a; 0.13 (sd±0.10)b 4th quarter: 0.32 (sd±0.33)a; 0.14 (sd±0.09)b duffield et al., 2012[46] amateur rugby league tackles (tackling and tackled)/game 22 (sd±9) king et al., 2012[6] professional rugby league total match tackles (tackling and tackled) 657 mclellan and lovell, 2012[47] national rugby league tackling/game tackled/game 19.9 (sd±10.5)a (forwards: 26.1 [sd±15.3]; backs: 10.7 [sd±8.9]) 12.2 (sd±3.6)b (forwards: 13.8 [sd±5.2]; backs: 11.7 [sd±4.6]) twist et al., 2012[48] european super league tackling/game tackling/minute tackled/game tackled/minute forwards: 25.5 (sd±13.7)a; 0.5 (sd±0.2)b; 12.7 (sd±6.1)c; 0.3 (sd±0.1)d backs: 13.6 (sd±7.9)a; 0.2 (sd±0.1)b; 11.6 (sd±3.4)c; 0.1 (sd±0.04)d johnston et al., 2013[49] amateur rugby league tackling/minute 0.3 (sd±0.1) mcguckin et al., 2014[50] national rugby league tackling/game home games: 14.3 (sd±6.7); away games: 18.4 (sd±9.2) cummins and orr, 2015[51] national rugby league tackling/game tackling/minute tackled/game tackled/minute hit-up forwards: 21.5 (sd±6.0)a; 0.53 (sd±0.08)b; 9.0 (sd±3.8)c; 0.20 (sd±0.04)d wide-running forwards: 20.5 (sd±5.0)a; 0.39 (sd±0.10)b; 8.0 (sd±3.6)c; 0.20 (sd±0.10)d adjustables: 17.0 (sd±12.5)a; 0.41 (sd±0.20)b; 5.0 (sd±4.5)c; 0.1 (sd±0.00)d outside backs: 7.0 (sd±6.0)a; 0.08 (sd±0.07)b; 11.2 (sd±2.1)c; 0.1 (sd±0.02)d fletcher et al., 2015[52] european super league tackling/game tackled/game forwards: 24 (sd±13)a; 8.5 (sd±5)b ; backs: 8 (sd±10)a; 9 (sd±4)b adjustables: 14 (sd±12)a; 4 (sd±4)b speranza et al., 2015[53] semi-professional rugby league tackling/game forwards: 24.3 (sd±6.5); backs: 13.2 (sd± 8.5) gardner et al., 2017[17] national rugby league total match tackles (tackling and tackled) 632.1 dempsey et al., 2018[54] senior international male rugby league tackling/game tackling/minute tackled/game tackled/minute forwards: 25.5 (sd±8.4)a; 0.47 (sd±0.23)b; 10.5 (sd±3.6)c; 0.20 (sd±0.10)d backs: 13.4 (sd±9.5)a; 0.16 (sd±0.11)b; 11.9 (sd±5.2)c; 0.15 (sd±0.08)d dempsey et al., 2018[54] junior international male rugby league tackling/game tackling/minute tackled/game tackled/minute forwards: 19.2 (sd±10.0)a; 0.34 (sd±0.13)b; 6.5 (sd±3.5)c; 0.12 (sd±0.06)d backs: 10.0 (sd±6.7)a; 0.13 (sd±0.08)b; 5.3 (sd±3.5)c; 0.06 (sd±0.04)d woods et al., 2018[55] national rugby league total match tackle attempts 325.0 (sd±39.7) woods et al., 2018[55] under-20 holden cup total match tackle attempts 283.4 (sd±35.6) original research sajsm vol. 33 no. 1 2021 6 conclusion this review synthesises tackle injury and tackle frequency performance studies in rl, with the goal of facilitating tackle injury prevention and performance research, and acting as a reference document for coaches and practitioners. based on the search criteria, a total of 53 studies were found: 32 focused on tackle injury epidemiology and 21 focused on tackle frequency. in general, over 600 tackles may occur during a rl match. each forward executes about 20-25 tackles, which is double that of backs. in contrast, forwards and backs carry the ball into the tackle, i.e. being tackled, at similar frequencies. tackle injury frequencies (both overall and time-loss injuries) ranged between 47%-94% at the professional level, and between 38%-96% for the lower levels of play. a greater proportion of severe time-loss injuries occur during the tackle at the professional level in comparison to lower levels of play. furthermore, most time-loss and overall injuries occur to players who are tackled, i.e. ball carriers, across all levels of play. conflict of interest and source of funding: the authors declare no conflict of interest and no source of funding. author contributions: nb and sh made significant contributions to the conceptualisation, design and drafting of the 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[doi: 10.1519/jsc.0000000000001058][pmid: 26813629] briscess print ready joint sasma and bricscess congress 2019 bricscess abstracts invited speakers presentations index title name surname abstract title i01 ass prof dr maria abulkhanova online and distance learning for physical education as a part of university curriculum i02 ass prof dr govindasamy balasekaran prediction of human performance in sports i03 prof dr myriam guerra-balic the linkage of holistic health to unsdg 17: spanish perspective i04 prof dr jongzhen (ginger) yang health policy approach to address injuries among children participating in sports i05 prof dr giyasettin demirhan the connection of cognitive function and physical activity in students: current research and implication i06 dr lyndon bouah an analysis of the implementation of the national sport and recreation plan in the western cape i07 prof dr larry durstine physical activity, exercise, blood lipids and lipoproteins: implications for prevention of chronic metabolic disorders i08 prof dr luminita georgescu practical approach of sport injuries prevention – a romanian perspective i09 prof hans de ridder is teaching the use of bmi to classify obesity and overweight outdated? i10 prof dr gulshan khanna creating a sporting culture in india for health promotion and achieving excellence in sports i11 prof dr kim graber the sustainability of high-quality physical education programming i12 dr miranda chin dancing with the world: aim for globalize harmony with holistic health through performing and education i13 prof dr nara oliveira reform in physical education and sport in brazil: new perspectives and possibilities of best practices i14 prof dr chee keong chen do antioxidant supplements improve sports performance and health? : a malaysian perspective i15 ass prof dr ricardo uvinha leisure and health in developing countries: a dialogue with the sustainable development agenda in brazil i16 prof maya van gent the relationship between selected body composition components and self-efficacy among 12-14 year-old rural adolescents in the 2 eastern cape province of south africa. purpose of the study i17 prof dr xiaozan wang current state of china’s outstanding traditional sports culture in curriculum and teaching of physical education in primary and secondary schools i18 prof erika zemkova testing children and youth fitness and sportspecific performance keynote speakers index title name surname abstract title k01 prof dr gudrun doll-tepper healthy lifestyle and physical activity – a call for networking and collaboration k02 prof dr stephen kopecky physical activity and benefits on reduction in chronic disease physical activity and benefits on reduction in chronic disease k03 prof dr anita pienaar kinderkinetics, physical activity and health: a south african perspective oral presentations index title name surname abstract title o01 mr ghaleelullah achmat the impact of multiple behaviour health intervention strategies on coronary heart disease risk, health-related physical fitness, and health-risk behaviours among firefighters in the cape metropole o02 mr fikreyesus adula training load and quality of recovery in ethiopian higher league football players o03 dr leyla ataş balci the effect of kinesio taping and low energy laser application in myofascial pain syndrome o04 dr leyla ataş balci the relationship between nomophobia and physical activity among students in turkey o05 mr curt barnes training loads and injury profiles in elite south african rugby players o06 mr curt barnes injury profiles and illness rates in elite south african rugby players o07 prof susan bassett prevalence and type of injuries in south african trail runners o08 mrs jacqueline bonnema the effect of a three month hopsports brain breaks® intervention programme on the attitudes of grade 6-learners towards physical activity and fitness. o09 prof candice christie workload does not impact performance responses in the indian premier league cricket o10 dr elna de waal influences of early perceptual-motor proficiency, gender, overweight and socioeconomic status on academic achievement of 3 primary school children: longitudinal data of the north-west child study o11 mrs kimberly-ann decina a nine-week pilates exercise programme reduces pain in the upper body of female office workers o12 mr steve den hollander tackle and ruck technique proficiency within academy and senior club rugby union o13 prof kele ding associations of physical activity level and risk of substance use and mental health-related disorders in us youth o14 prof ronualdo dizer end of season evaluation of coaches by athletes (eseca) of the university of the philippines o15 prof dorita du toit teacher perceptions of learner motivation after the completion of a physical education in-service training program o16 dr gary gabriels a 15 year historical journey of dietary/nutritional product assessment in south africa consequence opportunity progress excellence o17 prof luminita georgescu practical approach of sport injuries prevention – a romanian perspective o18 mr barry gerber differences in strength and aerobic endurance between preand post-menarche girls during mid-adolescence: a two-year follow-up study cognition and formation in selected grade 1 children o19 mr steve gibling creating a holistic university wellbeing strategy that connects and inspires staff and students o20 mr gregory roy gordon the effect of law changes on match loads in university rugby union players during the fnb varsity cup o21 dr heinrich grobbelaar social capital development through the songo.info cycling, academic support and life skills program: program leader and participant perspectives o22 mrs elandie immelman kinematics and muscle activation in adolescent tennis players with and without lower back pain o23 dr serap inal gender differences on the effects of technological tools on postures of children between 11-14 years o24 mr siyabonga henry kunene anterior knee pain, risk factors and impact on the quality of life among runners in underresourced communities, ekurhuleni 4 o25 mr siyabonga henry kunene rehabilitation approaches to anterior knee pain among runners: a scoping review o26 dr cinthia lopes da silva education for leisure and the use of comic books in physical education classes o27 mr warren lucas the experienced health benefits of sport participation among young people: a south african case study of gymnastics o28 dr smart mabweazara physical activity and selected sociodemographic variables as predictors of nutritional knowledge amongst an adult south african sample of low socioeconomic status o29 mr makhaya johannes malema youth leadership development using leisure education for youth with disabilities in south africa o30 dr zanean mcclain perceptions of adapted physical education services through the lens of asian parents o31 prof makama andries monyeki association between physical activity levels and body fat percentage in 6-8 year old children from a black south african population: bc-it study o32 dr kim nolte measuring physical activity in south african grade 2 and 3 learners: a self-report questionnaire versus pedometer testing o33 ms simamkele nyangiwe perceptions of physical activity participation among university students living on and off campus in the university of the western cape. o34 prof foong kiew ooi an investigation of the association between vitamin-d receptor gene bsmi polymorphism, bone health status, and muscular performance in malay young female athletes and non-athletes o35 ms maphoko phindile phatlane effect of a 12-week aerobic exercise programme on percentage body fat, fasting blood glucose and dyspnea in insulin resistant obese female university employees in the western cape – a proposal o36 prof oscar yoshihiro santelices perception of athletes between coaches’ behavior and athletes’ motivation on selected collegiate table tennis athletes o37 mrs cornelia schreck preparing recreation professionals: graduate attributes expected of entry-level recreation professionals in a south african context o38 dr rakesh tomar metabolic controls and prevalence of depression symptoms: effects of sixteen weeks recreational football on male students 5 o39 ms koketjo biggy tsebe the influence of a mindfulness-acceptancecommitment intervention program on the mental toughness, self-efficacy and anxiety of male league softball players in south africa. o40 ms yu weng shanghai amateur games: a hallmark sports event for residents o41 dr a fouche leisure meanings of caregivers: a case study o42 dr martin pacholek student feedback and effect on different training stimuli in physical education classes 6 invited speakers presentations i01: online and distance learning for physical education as a part of university curriculum assoc. prof. dr. maria abulkhanova, department of physical education and sport science, moscow state academy of physical education, russia presenting author e-mail address: mabulkhanova@mail.ru abstract despite all efforts, the health of today's youth continues to decline. the problem is that two classes, or even one class, per week with a physical education teacher is not enough to form a habit and obviously there is not enough time for both developing motor skills and improving the health conditions of students. some of the students require more time and more effort from physical education teacher during the classes. certain conditions of the students health must be taking into account during the physical education process, for example cardiovascular disease. based on the collected data our physical education teachers and it department of the university build an online platform when a student can have online pe classes at home. the student must login to the web page of the academy then he can choose from a number of lectures according to his physical conditions. he can start to do exercises according to the video guidance of the lesson. the website contains all necessary theoretical information for students to be able to form motivation and build healthy habits, be physically active on their own. the teacher can see how much time did the student spend on the website as well he can give to the student multiple choice question tests to be sure that the theoretical information assimilated by the student. the results of the experiment were provided to be statistically different shows us that just physical education classes as well as just independent online classes are not working separately we need to have a joined efforts the physical education teachers and the pupils to get the results. physical education proses must include activities outside the classroom and internet technologies give us opportunities to make the education process more useful and meaningful for promoting the healthy lifestyle among young people, as a result, it will improve the quality of their life and make their life longer and better. 7 i02: prediction of human performance in sports associate professor associate professor, dr. g. balasekaran, phd, facsm, physical education & sports science, national institute of education, nanyang technological university, singapore presenting author e-mail address: govindasamy.b@nie.edu.sg abstract various sports require a combination of anaerobic and aerobic energy, thus the measurement of anaerobic peak energy or anaerobic performance is an important parameter of sports activities. the measurement of aerobic energy is well-researched and there is a standardised method; however, there are too many different methods to measure anaerobic performances such as blood lactate, maximal accumulated oxygen deficit (maod), oxygen debt, muscle biopsy etc. moreover, it is essential to utilise a method that is reliable, valid, easy and convenient. maod may be an accurate method but it is not easy and convenient to measure anaerobic performance. besides physiological methods, mathematical models may be used to measure anaerobic energy. as individual athletes come from different physiological backgrounds, they can be categorized according to their capacities in endurance and sprint capabilities. bundle et.al.(2003) developed the concept of anaerobic speed reserve (ansr) to measure anaerobic performance accurately. however, ansr can only be used to predict 3 to 240 seconds. therefore, a more accurate model incorporating timings greater than 240 seconds may be needed. a recently developed mathematical model called running energy reserve index (reri) may be a solution. reri has been able to significantly differentiate athletes of different training backgrounds. therefore, reri may be an accurate and non-invasive method to categorize athletes from different physiological backgrounds. 8 i03: the linkage of holistic health to unsdg 17: spanish perspective prof. dr. myriam guerra-balic1; prof. dr. verónica violant holz² 1principal investigator of the research group on health, physical activity and sport, fpceeblanquerna, university ramon llull, spain ²director of department of didactic and educational organization, university of barcelona spain presenting author e-mail address1 : miriamelisagb@blanquerna.url.edu presenting author e-mail addres²: vviolant@ub.edu abstract usually, when we think about the concept of disease, we relate it to a loss of health. but talking about health we should consider its determinants at the same time that the factors which can condition at the time that can facilitate both the individual and collective health state. unesco (2015) advices us about the importance to obtain 17 sustainable development goals included in the agenda 2030, on five of which we will focus: goal 3. good health and well-being; goal 4. quality education; goal 10. reduced inequalities; goal 11. sustainable cities and communities; and goal 17. partnership for the goals. planning these actions to achieve the goals from a health point of view implies designing good practices addressed to children and adolescents, and their families, in order to manage and transform the risk factors into options to promote healthy lifestyle. with all this, we can afford several collectives with risk due to different factors that can be related to the previous cited goals. our objective is to analyze the elements of these goals that pass on good practices, and to propose future actions that can be visualized in several environments (school, hospitals, homes, social places, community, etc.) and that guarantee the sustainability and support networks like the foundation for global community health (gch). this foundation has the following purposes: “to develop best practices regarding school based well-being programs, utilizing the whole school, whole community and whole child in cooperation with an international network of advisers” (gch, 2017). 9 i04: health policy approach to address injuries among children participating in sports prof. dr. jingzhen (ginger) yang, phd, mph, pediatrics and epidemiology, nationwide children’s hospital, the ohio state university, usa/china presenting author e-mail address ginger.yang@nationwidechildrens.org abstract sports and recreational activities are widely promoted as part of a healthy lifestyle for children. however, the high incidence of injuries among children participating in these activities could diminish the physical and psychological benefits gained from participating and pose a serious threat to the health and well-being of children. each year, at least 4.3 million sports and recreational injuries occur to school-aged children in the united states (us), with approximately 2 million being sports-related concussions, a form of traumatic brain injury (tbi). concussions are of particular concern for children since the brain is still developing during this critical period. untreated or improperly managed concussions can have longlasting, detrimental effects on young brains, affecting the child’s physical, cognitive, emotional, and sleep health. numerous efforts have been made in the us to prevent sports and recreational injuries, including sports-related concussions. one such effort to mitigate negative health consequences is a public health policy approach. in this presentation, an approach to address youth tbi prevention and control will be introduced and discussed. examples on state-level youth tbi laws will be used to illustrate how a public health policy approach is used to address sports-related concussion prevention and control. the presentation will cover what state-level youth tbi laws are, how these laws are implemented and enforced at local schools, how these laws are evaluated using data from a large, national sports-injury surveillance system, and what the impact of these laws is on the trends of new and recurrent concussion rates among us representative high-school athletes while participating in the 9 most commonly played sports across a period of 11 years (2006-2016) from preto post-law enactment. these results, along with those of others, suggest that more public health policy efforts are needed to focus on preventing concussions in the first place, such as preventing or reducing initial head or body impact among children who participate in sports and recreational activities. 10 i05: the connection of cognitive function and physical activity in students: current research and implication prof. dr. gıyasettin demirhan, head of physical education and sport education department, faculty of sports sciences, hacettepe university, turkey presenting author e-mail address: demirhang@gmail.com abstract the purpose of this paper is to explain the connection of cognitive function (cf) and physical activity (pa) in children and young people. it will be shared some research results about mental functions with this paper. a growing number of studies support the idea that physical exercise is a lifestyle factor that might lead to increased physical and mental health throughout life (hillman et. al., 2008). as we know that physical activity refers to all forms activity that requires physical effort, from simple house tasks to performance sports. this paper focuses on fundamental and specific movement skills, exercises and sport skills about the students at schools from elementary school to the university. research has suggested that physical activity might not only support to improve their physical health, but might also develop their cognitive functions. according to many research results, physical activity has important roles on improving mental functions, raising academic performance and developing positive attitude. for instance, physical activity promotes children’s and young people’s health and well-being in many ways. it has also been noted to have a positive effect on learning and cognitive functions, such as memory and executive functions and, as a result, possibly on academic performance (hilmann et.al., 2009; kwak et. al., 2009; tomprowski et. al., 2008). furthermore, many previously conducted studies have demonstrated that all forms of physical activity have a positive effect on the academic performance of children, and on the development of their cognitive characteristics. physical activity also affects development of positive attitude. (koca and demirhan, 2004; hünük and demirhan, 2010; cairney et al., 2012). 11 i06: an analysis of the implementation of the national sport and recreation plan in the western cape dr lyndon bouah, chief director for sport and recreation, department of cultural affairs and sport, south africa. presenting author e-mail address: .bouah@westerncape.gov.za abstract it is widely accepted that sport has the potential to serve as a tool for development as well as a catalyst for social and personal change. the national department of sport and recreation (srsa) has recognized the role that sport can play in building a better society in its recently published document the national sport and recreation plan (nsrp). the study analysed the implementation of the nsrp in the western cape and developed options for the improvement of the implementation of the national sport and recreation plan in the western cape. the study analysed the factors that are necessary for an enabling environment to be successful to create an active and winning nation. by linking policy to implementation the study showed that the social benefits of sport can be extended to the broader social community. the fieldwork research was conducted with sport councils, sport federations, academy officials and senior government officials. the study found that the links between local, provincial and national government must be strengthened. the study further found that the level of commitment amongst the various spheres of government is not the same. the will may be there but the actual resources that must be committed is not readily made available. the 5-c protocol was used to analyse the nsrp and its current implementation within the western cape. communication was considered as a future addition to augment the 5-c protocol. the alignment between various national, provincial and local spheres of government was found to be lacking. it is recommended that the nsrp be brought into the annual performance plans, strategic plans, medium term expenditure framework and performance agreements of departments and senior management. it was found that the voluntary nature of organisations may act as a hindrance to the implementation of the nsrp. it is foreseen that the outcome of the study will assist in benchmarking best practices for implementation. the recommendations proposed by this study will provide options for laying the foundation for the successful implementation of the national sport and recreation plan in south africa. 12 i07: physical activity, exercise, blood lipids and lipoproteins: implications for prevention of chronic metabolic disorders prof. dr. larry durstine, distinguished professor, department of exercise science, university of south carolina, usa presenting author e-mail address: ldurstin@mailbox.sc.edu abstract the beneficial effects of regular exercise participation on plasma lipid and lipoprotein profiles have in recent years have been more clearly defined. presently, the many factors that influence lipid synthesis and catabolism, the interactions between lipids, lipoproteins, apolipoproteins (apo), and lipoprotein enzymes are better understood. though much has been learned regarding the plasma lipids, the various components of the different lipoproteins, and the various genetic and environmental factors that impact the lipoprotein metabolic pathways and eventually lipoprotein composition, many new questions remain unanswered. gender, aging, body fat distribution, dietary composition, cigarette smoking status, and regular exercise participation are factors that interact to modify lipoprotein metabolism and plasma lipoprotein composition. for example, intervention programs that reduce dietary fat and increase dietary carbohydrate while increasing daily physical activity can positively influence plasma lipid and lipoprotein concentrations and reduce coronary artery disease risk. this presentation will summarize the beneficial impact of exercise on blood lipid and lipoproteins. 13 i08: practical approach of sport injuries prevention – a romanian perspective prof. md., phd. luminita georgescu, department of physical education and sport, faculty of sciences, physical education and informatics, university of pitesti, romania. presenting author e-mail address: kinetopit@yahoo.com abstract introduction: with the continuous increase in the number of practitioners, currently there is also a significant increase in the risk of injury due to sport activities, whether they is for performance or leisure. continuous adaptations and improvements of the equipment, of the training techniques and regulations are some of the concerns that specialists in the field of sport do have in respect with the prevention of specific injuries. methods. health status screening, medical forms and certificates to approve sports participation are some of the methods used by the sports medicine staff to prevent injuries and the risk of injury. we used a retrospective longitudinal study and analyzed the medical records of 1200 athletes (300 playing individual sports and 900 practicing sports games) over a period of five years. through a structured interview we gathered data of the athletes’ health status and also their injury records during training and competition. we were interested also to range the athletes’ characteristics depending on their anthropometric measurements and physical development, clinical and paraclinical examinations and aerobic and anaerobic exercise capacity. our aim was to identify the biological profile of athletes at high risk of injury and the correlation of individual sanogenic factors with the sport’s requirements, respectively the training stage. starting from this, we wanted to project an intervention strategy, based on a combination of methods to increase the fitness level, pharmacological treatment, hygiene-dietetic measures and physiotherapy programs. results & discussion. after processing all data, some injuryassociated risk factors were identified: deficiencies in the athletes’ selection by sports branches; inconsistency between the physical development of the athletes and the sport requirements; paucity of the body’s ability to adapt to the physical effort according to the stage of sports training. conclusion. there is a close correlation between the initial clinical and paraclinical assessment and then the periodical assessment in determining the athlete's health status and his effort adaptation ability. moreover, the correction of biochemical imbalances has a special role in preventing the risk of injuries. 14 i09: is teaching the use of bmi to classify obesity and overweight outdated? professor hans de ridder, professor and director, school of human movement sciences, north-west university, potchefstroom, south africa. presenting author e-mail address: hans.deridder@nwu.ac.za abstract introduction: among many weight-to-height ratios, the body mass index may be the most common index. while body mass index was proposed in 1972, the equation-mass (kg)/stature (m)² was originally proposed in 1832 and named the quetelet index. in 1997, the world health organization chose to utilize body mass index as an index to assess overweight and obesity in adults and the international classification scheme was proposed. although body mass index was not originally proposed to identify obesity, body mass index has a quadratic relationship with percentage body fat in both genders. methods: several large-scale epidemiological studies reported that body mass index is positively associated with a number of obesity-related chronic diseases, including cardiovascular diseases and type ll diabetes mellitus. while body mass index has been utilized in assessments of overweight and obesity, it is important to appreciate that it is simply a measure of heaviness, not of fatness, as it does not use any measures of body composition. a classic study by garn suggested three limitations of body mass index: (1) body mass index is stature dependent and in different directions at different points in the life cycle; (2) body mass index may be affected by relative leg length or relative sitting height; and (3) body mass index may reflect both lean and fat tissues to a comparable degree. conclusion: many studies have reported misclassification of individuals and variability in the relationship between body mass index and percentage body fat due to these limitations. such limitations are applicable to other weight-to-height ratio and therefore it is important to use these indices with caution, particularly when the index was applied to individuals and special population. for a better use of body mass index to different racial groups the world health organization expert consultation proposed new cut-off points (i.e. 23 kg/m², 27.5 kg/m², 32.5 kg/m² and 37.5 kg/m²) as public health action points in 2004. 15 i10: creating a sporting culture in india for health promotion and achieving excellence in sports prof. dr. gulshan khanna, director project indian institute of sports science and research ministry of youth affairs and sports, dean, faculty of applied sciences, manav rachna international university, india presenting author e-mail address: glkhanna.acess@gmail.com abstract india has so far won a total of 28 medals – with 88% of its gold medals coming from hockey alone since 1900. despite its immense talent base and growing economic prowess in recent years, historical legacies rooted in our byzantine sporting system and a general absence of a physical activity culture have meant that india has so far been unable to produce elite-level global success in sports that is commensurate to its huge potential, size and role as a rising power. on the initiative of prime minister olympics task force was appointed by the union ministry of youth affairs and sports to recommend systemic steps for improved indian performances at the 2020, 2024 and 2028 olympics and to create a road map for realizing the huge potential of indian sports and improve health through sports. a detailed feedback from all stakeholders in indian sport, through various meetings held in state capitals, met several athletes and para-athletes and studied health promotion, physical activity, sporting culture undertaken in other countries for international benchmarking to understand global best practices and whether they can be adapted to reform the indian system of health promotion and sports improvement. various steps have been recommended to improve the physical activity and create a sporting culture for improving health promotion in india to achieve excellence in sports. 16 i11: the sustainability of high-quality physical education programming prof. dr. kim graber1, and gabriella mcloughlin 1associate head, department of kinesiology and community health, director, campus honors program , the university of illinois at urbana–champaign, usa presenting author e-mail address: 1 kgraber@illinois.edu abstract approximately 15% of children (aged 2-19 years) in the united states are classed as overweight, with an additional 17% classed as obese (ogden, carroll, kit, & flegal, 2012). in order to address the obesity epidemic, k-12 schools in the united states have been encouraged to develop and implement a comprehensive school physical activity program (cspap) that can be infused into the school curriculum in order to increase opportunities for children to be physically active. this multi-dimensional model includes quality physical education, which serves as the cornerstone, along with before and after school physical activity opportunities, physical activity within the school, staff involvement in the program, and community engagement. physical educators have been encouraged to take an active role in facilitating the cspap initiative, and professional organizations support its implementation in schools throughout the us. unfortunately, there is a paucity of research regarding the effectiveness of cspaps, and only one study addresses the effectiveness of those programs that have been deemed successful or have received national recognition for their efforts (mcloughlin & graber, in review). in the one study that has been conducted, it is clear that sustaining the quality of such programs is difficult, particularly as a result of administrative and staff turnover and little time for physical education colleagues to communicate with each other about program maintenance. although the successful development of an individual school cspap is often the result of the efforts of only one person, or a small group of individuals, it requires continuous support from multiple stakeholders within and outside the school community to sustain the quality of the program. grounded in the social ecological model (bronfenbrenner, 1989; stokols, 1992), this presentation will address the difficulty of sustainability of high quality physical education, particularly within an educational microcosm that for many years has been accepting of low quality physical education across the nation. 17 i12: dancing with the world: aim for globalize harmony with holistic health through performing and education dr. miranda chin, mfa, mba, artistic director, miranda chin dance company principal, danceland school, hong kong-china presenting author e-mail address: mirandachinsl@gmail.com abstract the chinese culture and philosophy got over 5,000 years in history, while martial arts and tai chi is one of the most representative elements in it. through applying these elements into simplified contemporary dances, the general public can easily get in touch with dances and getting good health and be able to sense the spirit of chinese culture particularly the feeling of harmony with the nature. chin had produced eight series of martial art and dances for reflecting the source of the martial arts, principle of movement, yi philosophy, the five elements of nature, health and living philosophy. chin will explain the creation process of these eight series of dance including how she did the research and development. we see and feel then we dance, we dance to show what we see and feel, that means dance is a body language. it is therefore dances are the history of people's culture and philosophy. thus chin's dance tells the contemporary ways, shows the culture and spirit of chinese. through explanation, video, this presentation may lead students and professionals to understand what chin's dances bring to them …… chinese culture, chinese philosophy, good health, spiritual state via contemporary dynamic movement. then she will share her concept and process of her recent artistic development is on mergering chinese culture into simplifed dances for promoting chinese culture and health and is now has over 56 countries applying it. 18 i13: reform in physical education and sport in brazil: new perspectives and possibilities of best practices prof. dr. nara oliveira, head, human movement sciences department, federal university of sao paulo, brazil presenting author e-mail address: nara.rejane@unifesp.br abstract physical education (pe) in brazil was introduced under eugenic and hygienic principles, in the early 20th century, when became a mandatory in the school curriculum. on the first half of that century, gymnastics was the main content, derived from european methods. the sport became relevant on the school curriculum after the 1960's, during the military regime, as a way to social control. the return of democracy in 1980's opens a new chapter to pe and sport, with the curriculum reform. new pe and sport paradigms were set up, under the educational and cultural perspective. in the 1990’s, curricular guidelines has published by brazilian ministry of education, highlighting pe as relevant to the human development, as well the sport, through the curricular or extra curricular activities, both inside or outside school. over the last 20 years, public policies from brazilian ministry of education, ministry of sports and also ministry of health has been developed, focusing pe and sport as a tool for human education in a holistic perspective. additionally, the investment on pe teacher training and research in the area has also been increased, to developing best pedagogical practices. however, the way forward is a great challenge, considering the cultural and economic brazilian diversity. in this context, the purpose of this presentation is to provide data regarding the new perspectives and possibilities of best practices, in the face of the brazilian pe and sport reform over the last years. 19 i14: do antioxidant supplements improve sports performance and health? : a malaysian perspective professor dr. chee keong chen, exercise and sports science programme, school of health sciences, universiti sains malaysia, 16150 kubang kerian, kelantan, malaysia. presenting author e-mail address: ckchen@usm.my abstract free radicals are reactive oxygen species which are highly reactive because of an unpaired valence electron. they are capable of damaging healthy cells and thus have been implicated in the pathophysiology of many diseases such as cancer, atherosclerosis, rheumatoid arthritis and neurodegenerative disease. antioxidants, on the other hand, are substances that scavenge free radicals and offer protection from the damaging effects of free radicals. nevertheless, oxidative stress occurs when the rate of production of free radicals exceeds the body’s antioxidant capacity to detoxify them. research data demonstrating significant increases in f2 isoprostanes and lipid hydroperoxides following exhaustive exercise corroborate that exercise induces free radical production. it has been postulated that free radicals might also damage the sarcoplasmic reticulum resulting in reduced calcium release during depolarisation of the muscle and consequently lead to muscular fatigue. thus, numerous studies have investigated the efficacy of various antioxidants in ameliorating the deleterious effect of oxidative stress on sports performance. previous studies which have shown positive effects of antioxidants on skeletal muscle endurance performance were n-acetylcysteine, pycnogenol, quercetin, beetroot juice, cashew apple juice, resveratrol and montmorency powdered tart cherries. several studies on the effects of various nutritional supplements with antioxidant properties on endurance performance and antioxidant status have been carried out in our sports science laboratory, school of medical sciences and school of health sciences, universiti sains malaysia. these supplements include palm vitamin e, caffeine, panax gingseng, eurycoma longifolia jack (tongkat ali), honey and bee bread. the main findings of these studies will be presented during my talk. 20 i15: leisure and health in developing countries: a dialogue with the sustainable development agenda in brazil assoc. prof. dr. ricardo uvinha, vice dean, school of arts, sciences and humanities leader of the interdisciplinary group of leisure studies, graduate program in physical activity sciences, university of sao paulo (usp), brazil presenting author e-mail address: uvinha@usp.br abstract the sustainable development agenda (sdgs) of the 2030 agenda for sustainable development was adopted by world leaders in 2015 at the united nations (un) summit. according to the un, the sgds are unique as global goals in that they call for action by all countries to promote prosperity while protecting the planet. it was established seventeen goals, being the third one “good health and well-being” which states that ensuring healthy lives and promoting the well-being for all at all ages is essential to sustainable development. brazil, the “b” letter of brics, is considered a developing country with a strong influence in economic and political sectors in south america. as well as in other countries, non-communicable diseases have increased in brazil and are the leading cause of death in adults. prevention and early diagnosis are essential for promoting health and reducing mortality, not only because obesity is a major risk factor for other diseases, but also because it interferes with length and quality of life. in order to encourage physical activity, it is critical to stimulate people to identify physical activities that give them pleasure. a relevant factor for the promotion of regular physical activity is the creation and use of safe public spaces. safety on the streets is also an essential factor, and this involves urban planning for recreation facilities, bicycle lanes, sidewalks that are in good condition and investments in parks and public facilities. this presentation aims to develop a dialogue with the sdgs, especially the goal regarded to health and well-being, describing several initiatives have already been developed in this regard in brazil. these include the understanding of leisure as a social right and a vital element for the promotion of health in this country with the creation of bicycle lanes and trails for hiking, revitalization of parks, and street closures at certain times of the day. 21 i16: the relationship between selected body composition components and self-efficacy among 12-14 year-old rural adolescents in the eastern cape province of south africa. purpose of the study prof. maya van gent, associate professor, human movement science department, university of fort hare, south africa presenting author e-mail address: mvangent@ufh.ac.za abstract body composition changes drastically in both males and females during the adolescent years. the changes may have a negative effect on their physical health as well as psychological wellbeing, with respect to attributes such as self-efficacy. being either overweight or obese during adolescence has social, economic and psychological consequences, which include low selfefficacy. consequently, the aim of this study was to investigate the relationship between anthropometric body composition components and self-efficacy, by conducting a comparison of self-efficacy levels among normal, overweight and obese 12 to 14-year-old rural adolescents in the eastern cape province of south africa. overweight and obese boys and girls presented with high levels of self-efficacy, which is in contradiction to other international studies. the results suggest that a positive relationship exists between certain body composition components and self-efficacy. it seems likely that cultural beliefs may exert an influence on the psychosocial perceptions of adolescents in relation to body size, consequently affecting self-efficacy levels. these findings pose a challenge in the efforts of combatting overweight and obesity in adolescents. 22 i17: current state of china’s outstanding traditional sports culture in curriculum and teaching of physical education in primary and secondary schools prof. dr. xiaozan wang, dean, yangtze youth scholars of chinese ministry of education, school of physical education and health, east china normal university, china presenting author e-mail address: xiaozanwang@163.com this paper aims to promote china’s outstanding traditional sports culture and understand its current state in curriculum and teaching of physical education at primary and secondary schools. a questionnaire survey was conducted on 214 frontline teachers from 212 schools of 18 chinese provinces and cities; an in-depth interview with 66 teaching and research personnel of physical education, principals and frontline pe teachers across the country; and a field investigation in 6 primary and secondary schools in henan province. the results show that: 1) various types of traditional sports projects are conducted at schools and 56.54% schools promote traditional sports culture mainly through school clubs or extracurricular activities; 2) teaching staff, quality of teachers, textbooks, sports venues and equipment of traditional sports should be improved; 3) the way of china's outstanding traditional sports culture entering the school should be based on local traditional sports culture; 4) the support of local education policy is a basic guarantee for china’s outstanding traditional sports culture entering curriculum, teaching materials and class; 5) hiring professionals of traditional sports culture to participate in traditional sports activities at school is a temporary and effective way of solving the shortage of teachers; 6) china's outstanding traditional sports must be moderately modified with innovation before it enters the school; 7) the integration of china’s outstanding traditional sports culture is an effective way of inheriting the sports culture; 8) colleges and universities should strengthen the training of traditional sports professionals to improve their ability to inherit and exert their influence to develop traditional sports culture. 23 i18: testing children and youth fitness and sport-specific performance prof. erika zemková, ph.d. faculty of physical education and sport, comenius university in bratislava, slovakia presenting author e-mail address: erika.zemkova@uniba.sk abstract recently, we proposed a long-term sport diagnostic model that includes seven age-related stages: stage 1 (6 to 9 years), stage 2 (10 to 14 years), stage 3 (15 to 18 years), stage 4 (19 to 24 years), stage 5 (25 to 44 years), stage 6 (45 to 64 years), and stage 7 (65+ years). within this model, we designed tests specifically tailored for these age categories. targeting young population, our approach to physical fitness testing of school age children was presented at gofpep 2014. so far, a variety of tests have been developed for children and adolescents. however, frequently used field tests do not sufficiently reflect various aspects of physical fitness relevant to a particular age and are not sensitive enough to exercise induced changes specific to a particular sport. these traditional methods of assessing the physical fitness of children and adolescents only partially fulfill current needs for testing under sportspecific conditions. therefore, testing batteries for young individuals should get a makeover. experience showed that young people participate more intensively and also reach higher exercise goals than with conventional methods when computerized diagnostic and training systems are used. for instance, task-oriented balance tests based on visual feedback control of body position or the agility test performed under simulated competitive conditions seem to be more suitable for children and adolescents than traditional field tests. both of them are similar to computerized games which may enhance the attention and motivation of children to exercise. proposed tests for assessment of physical fitness in children and adolescents can be adjusted according to requirements of particular sports and serve as a basis for sport-specific model of athlete's performance testing. our recent review of testing methods used for the evaluation of the effect of neuromuscular training on sportspecific performance in young athletes will complement the presentation. acknowledgement: this work was supported by the ministry of education, science, research and sport of the slovak republic and the slovak academy of sciences (no. 1/0824/17). 24 keynote speakers k01: healthy lifestyle and physical activity – a call for networking and collaboration prof. dr. gudrun doll-tepper, vice-president, german olympic sports confederation chairperson, german olympic academy,professor of sport science/inclusive education department of education and psychology, freie universitaet berlin, germany presenting author e-mail address: gudrun.doll-tepper@fu-berlin.de abstract many initiatives and declarations exist at international, national and local levels focussing on the promotion of a healthy lifestyle and increased physical activity over the lifespan. enormous efforts, undertaken by governments and non-governmental organisations, exist to inform people and to raise awareness about the benefits of a physically active lifestyle and healthy eating. however, despite numerous campaigns and programmes, e.g. by the world health organization (who), the united nations educational, scientific and cultural organization (unesco) and many international organisations of physical activity, physical education and sport science, the global problem of a decline in physical activity levels remains and gets even worse. data exist from different countries around the world which make clear the enormous costs of inactivity affecting individuals and society. it is recommended to increase multiorganisational efforts towards changes in lifestyle and to intensify networking and collaboration at all levels. selected examples will be presented, e.g. focussing in particular on children and youth, on women, on men, on persons with disabilities and on persons with different cultural backgrounds. recently, new programmes have been introduced which address people up to 100 years of age and beyond. these initiatives are important in those regions of the world where we notify an increase of life expectancy. various programmes have also been implemented which offer participation for persons with health issues, such as depression and cancer. in some countries, various forms of collaboration and cooperation amoungst researchers and practitioners from various professional backgrounds exist, which can be used as good examples and an indication for future developments. 25 k02: physical activity and benefits on reduction in chronic disease prof. dr. stephen kopecky, m.d., facc, facp, faha, faspc, immediate past president, american society for preventive cardiology, professor of medicine, college of medicine, mayo clinic, usa presenting author e-mail address: kopecky.stephen@mayo.edu abstract lifestyle is now the leading risk factor for early cardiovascular death and chronic disease worldwide, and it is estimated that 80-90% of our health is primarily based on individual lifestyle. over the past one to two decades, the obesity rate has increased markedly in countries of both upper and lower socio-economic status, including brics countries. the two primary components of lifestyle are physical activity and diet. as work requirements push us towards a more sedentary lifestyle, it is critical that we try to maintain regular physical activity, including both moderate frequent daily short episodes to counter our stationary work habits and less frequent episodes of vigorous interval activity. to achieve this, an interdisciplinary approach including teamwork and integration between healthcare providers, exercise physiologists, and dietitians will be required. new healthy food options along with opportunities for safe physical activity will be essential. the lifestyle and sports medicine fields must be positioned to lead this lifestyle transformation via population, government, and industry education. 26 k03: kinderkinetics, physical activity and health: a south african perspective prof. dr. anita pienaar, chair: kinderkinetics, south african professional institute for kinderkinetics (sapik), school of human movement sciences, north-west university, south africa presenting author e-mail address: anita.pienaar@nwu.ac.za this presentation will focus on kinderkinetics as a specialized health profession that are used in a south africa context to address the challenges of physical inactivity among children in support of the exercise-as-medicine preventative belief. over many years south africa had major challenges due to various reasons to address the physical activity needs and the subsequent health problems of south african children growing up in very diverse circumstances. this include taking physical education as a subject out of the school curriculum in 1996, which at that time created a big void in expertise to address, not only the motor and physical developmental needs of young children, but also the problems that arise as a result of physical inactivity. this as well as a need towards creating new avenues that can create job opportunities to address work shortages in our country, provided a much needed impetus towards the developing of this new curriculum where we started to train health practitioners to become specialists that can address the improvement of health and well-being of children, also on an entrepreneurial level, based on physical activity. this journey towards developing this professional field and where it stands today, will be discussed. however, although scientific evidence of the importance of sound motor and physical development to the health and well-being of children, also on a cognitive level, are well documented, it is also important to provide evidence based research but also practice based evidence as proof of successful interventions. research findings from within the kinderkinetics program that can corroborate that the delivering of different kinderkinetics programs has scientific merit in a school, clinic, therapeutic and sport environment, will also be discussed. 27 oral presentations o01: the impact of a multiple health behaviour intervention strategy on the prevalence of coronary artery disease risk factors, health-related physical fitness, functional occupational performance, health-risk behaviours, and work-related musculoskeletal disorders among municipal firefighters achmat, g1, leach, l1 1,department of sport recreation and exercise science university of the western cape. republic of south africa presenting author e-mail address: gachmat@uwc.ac.za introduction: there is a compelling body of evidence that coronary artery disease (cad) risk factors are present in people of all ages. the extent to which the problem exists among firefighters in south africa (sa) has not been confirmed in the literature. aim: this study aims to assess the impact of a multiple health behaviour intervention strategy on the coronary artery disease (cad) risk factors, health-related physical fitness (hrpf), functional occupational performance (fop), health-risk behaviours (hrbs), and work-related musculoskeletal disorders (wmsds) among municipal firefighters in the city of cape town fire and rescue service (cctfrs). methods: an experimental study design will be used, wherein 212 participants will be randomly sampled and have baseline tests measured. thereafter, the participants will be randomized into four groups consisting of 54 firefighters per group, both males and females, i.e., one control group (cg), one health information (hig), one physical activity group (pag), and a multiple treatment group (mtg). the groups will be tested before and after a 12-week multifactorial intervention strategy. the intervention will be based upon prochaska’s transtheoretical model of behaviour change. data collection: participant information will be obtained using validated self-report questionnaires, namely, the physical activity readiness questionnaire (par-q), the stages of readiness to change questionnaire (srcq), the international physical activity questionnaire (ipaq), the adult combo health behaviour measures questionnaire (acbmq) and the nordic musculoskeletal questionnaire (msq). in addition, various physical and hematological (blood) measurements will be taken. the following measurements will be taken before and after the intervention programme: 1) coronary artery disease risk factors, namely, hypertension, obesity, fasting blood cholesterol and fasting blood glucose; 2) health-related physical fitness, namely, body composition, cardiovascular fitness, muscular strength, muscular endurance, and flexibility; and 3) functional occupational performance (six firefighting-specific tasks). furthermore, the following health-risk behaviours will be recorded, namely: physical activity, nutrition, managing stress, avoiding destructive habits, practising safe sex, adopting safety habits, knowing first aid, personal health habits, using medical advice, being an informed consumer, protecting the environment and mental well-being, as well as various work-related musculoskeletal disorders. where the outcome variables are normally distributed, the groups will be compared using repeated-measures anova. for outcomes with a non-normal distribution or ordinal level data, the nonparametric wilcoxon rank sum test will be used for group comparisons. for nonparametric methods, analysis will be done using cochran-mantelhaenszel (cmh) methodology, stratifying on the baseline values. for nominal level outcomes, groups will be compared by chi-square tests for homogeneity of proportions. where baseline values are needed to be incorporated into the analysis, this will be done using cmh methodology. a significance level p < 0.05 will be used to indicate statistical significance. ethical considerations: ethics clearance will be requested from the biomedical research committee at the university of the western cape, and permission will be requested from the 28 chief fire officer of the city of cape town fire and rescue service. participants will be informed about the nature and the scope of the study, including testing procedures, risks and benefits, prior to testing. participation in the study will be voluntary, and participants will have the choice to withdraw at any time without any negative consequences. data will be stored in a locked filing cabinet in the supervisor’s office, and electronic data on a password-protected laptop. all data will be stored for a period of five years before being destroyed. 29 o02: training load and quality of recovery in ethiopian higher league football players adula, fikreyesus daniel 1 van heerden johan 2 1 wachemo university, ethiopia, 2 department of biokinetics, exercise and leisure science, university of kwazulu-natal, south africa presenting author e-mail address: fikirfev@gmail.com introduction: it has been suggested that player fitness and the quality of training offered by coaches could pose a barrier to the performance standard in ethiopian football. there is no research-based approach to the methods used to monitor maximum and minimum intensity and volume of training imposed on the players and their recovery during the season. the purpose of this study was thus to monitor training load and recovery among football players in the ethiopian higher league over a pre-season and in-season period of the competition. methods: a squad of twenty-five male footballers (age 22.08 ± 1.41 years, weight 70.24 ± 6.45 kg, height 175.60 ± 7.01cm, bmi 22.78 ± 1.77) playing for a professional team in the ethiopian higher football league were tracked over a macrocycle of the season comprising ten weeks. rating of perceived exertion (rpe) and total quality of recovery (tqr) scores were recorded for 40 days. session training load (stl) was subsequently calculated as the product of session rated perceived exertion (srpe) and session training duration (std) in arbitrary units (au). results: similar perceived exertion mean values of 11.62 ± 1.56 and 12.20 ± 2.34 rpe (p>0.05) corresponding with ‘fairly light’ and ‘somewhat hard’, were recorded in preseason and in-season, respectively with ‘poor recovery’ similar ‘poor’ tqr recovery recorded for both the pre-season (11.09 ± 0.64) and in-season (11.2 ± 1.53). a higher mean stl incorporating duration of sessions was registered for the in-season (1009.34 ± 193.28 au (p≤0.0001) than for the pre-season (887.3 ± 117.09 au). variations across the in-season showed a decrease (p≤0.05) in stl from 3009.6 ± 750.69au at the beginning (week 3) to the middle (week 6) with 2610.0 ± 717.86au followed by an increase (p≤0.05) to 23369.6 ± 1773.99au at the end (week 10) of the season. corresponding perceived exertion and recovery at week 3 was somewhat hard (rpe 12.53 ± 3.10) and poor (tqr 10.44 ± 3.1) followed by a less taxing fairly light (rpe 10.97 ± 3.08) but poor recovery (tqr 10.31 ± 3.30) at week 6, and at week 10 perceived exertion was higher, but still approximating fairly light (rpe 11.36 ± 4.80) and recovery scores improved (p>0.05) slightly (tqr 11.39 ± 3.11) showing a matched perceived intensity of training and the degree of recovery. over the in-season, compared to week 3 and 4, a higher mean stl was recorded in week 5 (4039.2 ± 193.28 au (p≤0.0001) followed by a reduction in week 6 (2610.0 ± 717.86 au (p≤0.0001) and another increase at the end of the season in week 9 and 10 (3369.6 ± 1773.99 au (p≤0.0001). conclusions: monitoring the sessional training loads over the preand in season macrocycle showed evidence of periodization in the form of cyclic progression with respect to higher and lower volumes of training. corresponding perceptions of improved recovery during lighter phases of training were, however, not evident and requires further analysis to identify the specific aspects of fatigue experienced. 30 o03:the effect of kinesio taping and low energy laser application in myofascial pain syndrome ataş balci l1, büyükavcı nb1, yağmur s1, alkan m2, alkan ş3 1department of physiotherapy and rehabilitation, bahçeşehir university, i̇stanbul, turkey ²department of physiotherapy, bahçeşehir university, i̇stanbul, turkey ³institute of health sciences, bahçeşehir university, i̇stanbul, turkey. presenting author e-mail address: introduction: myofascial pain syndrome (mps) associated with active myofascial trigger points is a common problem can cause pain, muscle spasm, sensitivity, weakness, limitation of range of motion in the patients. physical therapy modalities and exercise are most commonly used in the treatment of mps. however the efficacy of low level laser therapy (lllt) and kinesio taping on patients with mps have not been investigated. the purpose of this study was to determine the effects of kinesio taping (kt) and lllt on pain intensity, sleep quality and quality of life in the patients with mps. method: forty-five volunteers (33 male; 11 female; mean age: 22.24±1.13 years) with mps of the upper trapezius muscle were recruited. participants were divided into 3 groups which consisted of i) lllt group (lllt+exercise application) ii) kt group (kt+lllt+exercise application) iii) an exercise group. lllt group received laser therapy once a week in a 4-week of treatment period. kt group received kinesio taping for the upper trapezius muscle in addition to lllt application. pain intensity, sleep quality and quality of life were assessed by visual analogue scale (vas), pittsburgh sleep quality index (psqi) and short form-12 (sf-12) respectively at the onset and at the end of four weeks of training period. results: pain intensity significantly improved following the 3 interventions (p<0.05). however, the changes in the vas of the kt group were significantly greater than those of the other 2 groups (p<0.05). there were statistically significant changes in the physical and mental functioning items of the sf-12 scores in the kt group (p<0.05). however, a statistically significant change was found only in the physical function items of the sf-12 in the lllt group (p<0.05). additionally, comparisons of changes in the sf-12 scores among the 3 groups revealed no significant differences (p>0.05). psqi scores significantly improved in the kt and exercise groups. however, no statistically significant changes were found in in the psqi scores of the lllt group (p>0.05). conclusion: our findings suggests that adding kt application to laser therapy may be effective for pain relief and increasing sleep quality and quality of life in patients with mps. 31 o04: the relationship between nomophobia and physical activity among students in turkey ataş balcı, l atas1 1department of physiotherapy and rehabilitation, bahçeşehir university, i̇stanbul, turkey presenting author e-mail address: introduction: the increasing use of new technologies involving personal computers, tablets and mobile phones are leading to changes in the habits and behavior of young adults. the problematic and excessive use of technology may have some negative effects such as nomophobia. nomophobia (no mobile phone phobia) refers to the fear and anxiety of not being able to access a mobile phone/smart phone or not being able to communicate through a mobile device. nomophobia and excessive usage of smart phones may lead to depression, low academic achievement, decreased of productivity and impairment of social and emotional functioning. moreover, nomophobia can be associated with physical activity, but the relationship between nomophobia and physical activity is not known. therefore the aim of this study is to determine the relationship between nomophobia and physical activity status of students. method: the turkish version of the nomophobia questionnaire (nmq) and international physical activity questionnaire (ipaq) were used to evaluate nomophobia and physical activity status of 137 students (84 female; 53 male; mean age: 22.10±1.80 years; bmi: 23.43±4.18) in the department of physiotherapy and rehabilitation at bahçeşehir university, in istanbul in turkey. spearman’s correlation was carried out to determine the relationship between nmq total scores and ipaq total scores. results: the mean total nmq scores and the mean total ipaq scores of the participants were 86.15± 30.86 and 2342.78±1807.49 respectively. most of the students were found to have severe nomophobia (48.2%). the results showed that, female students have a higher tendency to show nomophobic behaviors compared to male students (p=0.04) there was a statistically significant strong negative relationship between nmq total scores and ipaq total scores (r= -0.541; p=0.000). also, there was statistically significant moderate positive relationship between bmi results and nmq total scores (r=0.168; p=0.05). conclusion: the lower the level of physical activity, the higher the risk of exhibiting nomophobic behaviors. additionally; the current study indicated that the students with higher level of bmi tend to show more nomophobic behaviors. 32 o05: training loads and injury profiles in elite south african rugby players curt barnes1, theresa burgess1, kim buchholtz2 1division of physiotherapy, department of health and rehabilitation, university of cape town, south africa. ²division of exercise science and sports physiotherapy, department of human biology, university of cape town, south africa. presenting author e-mail address: curtbarnes@icloud.com introduction: across professional team sports, professional rugby union has one of the highest reported incidence of injury. despite the inherent risk of injury due to the high physical demands, training load in rugby union is an independent risk factor to injury. the super rugby tournament is a platform to further investigate injury and training load patterns within rugby union. the nature of the super rugby tournament has been associated with high rates of injury, but the relationship between training loads on injury profiles are unclear. methods: a descriptive, observational, surveillance study design over twenty-eight weeks. thirty-nine adult participants were recruited from one south african team over pre-season, early and late competition of the 2017 super rugby tournament. routinely collected data by the squads medical personnel was collated. training load data included squad size, training or match day, the duration of training or matches, and internal and external training load measures for training and matches. injury data included the participants age, the injury counts, the type of injury, the main and specific anatomical location, and the mechanism and severity of injury. results: the overall incidence of injury was 12.8 per 1000 player hours. the majority (48.8%) of injuries occurred in the early competition phase. a significant negative correlation between injury and internal training loads were detected in the preseason phase (r = -0.34, p = 0.03). no significant correlations were detected between external training load and injury. odds ratios were used to assess the associations between internal and external acute to chronic ratios, and injury. no significant relationships were found. conclusion: the incidence of match injuries in this study was significantly higher than previously reported incidence rates in the super rugby tournament. the profiles of match and training injuries, anatomical location, type, mechanism and severity of injuries are similar to previous studies. internal training load and injury were significantly correlated in the preseason phase. further studies are required to determine the relationship of training loads on injury profile over consecutive seasons and in multiple teams. 33 o06: injury profiles and illness rates in elite south african rugby players curt barnes1, theresa burgess1, kim buchholtz2 1division of physiotherapy, department of health and rehabilitation, university of cape town, south africa. ²division of exercise science and sports medicine, department of human biology, university of cape town, south africa. presenting author e-mail address: curtbarnes@icloud.com introduction: professional rugby union is a popular international team sport and is known to have one of the highest reported incidences of injury and illness across sporting codes. the super rugby tournament is played annually between professional rugby union teams and is one of the most competitive sports tournaments in the world. the demanding nature of the tournament has been associated with high rates of injury and illness. epidemiological data on injury profiles and illness patterns during these professional tournaments are an essential first step in the injury prevention process. methods: a descriptive, observational, surveillance study design was conducted during the 2017 super rugby tournament. thirty-nine adult participants were recruited from one south african franchise over a complete season of twentyeight weeks, including preseason, early and late competition. data were collected routinely by the team medical personnel. descriptive and injury data included the participants age, the injury counts, the type of injury, the specific anatomical location, and the mechanism and severity of injury. illness data included illness counts, the bodily system affected, symptoms and cause of illness, the specific diagnosis and time-loss. results: the overall incidence of injury was 12.8 per 1000 player hours. the majority (48.8%) during the early competition phase. the incidence of match injuries (241.0 per 1000 player hours) was significantly higher than training injuries (3.3 per 1000 player hours). the lower limb sustained the greatest proportion of injuries (62.5%). muscle or tendon injuries accounted for 64.9% of all injuries. the tackle accounted for 28.8% of all injuries and 37.5% of all injuries were of a ‘moderate’ severity. the proportion of players that sustained a time-loss injury was 76.9% (n = 30). the proportion of players that sustained a time-loss injury severe enough to prevent eight days or more of participation in training or matches was 25.6% (n = 10). the overall incidence of illness was 1.8 per 1000 player days. twenty-eight percent of players (n=11) acquired an illness. acute respiratory tract infections (28.6%) was the most common diagnosis and the majority of illnesses (64.3%) did not result in time-loss. conclusion: the incidence of match injuries in this study was significantly higher than previously reported incidence rates in the super rugby tournament. the profiles of match and training injuries, anatomical location, type, mechanism and severity of injuries are similar to previous studies. illness rates were significantly lower than reported in previous studies. further studies are required to determine the injury profiles and illness rates over consecutive seasons and in multiple teams. 34 o07: prevalence and type of injuries in south african trail runners susan h. bassett, harry van wyk steyn swart introduction: trail running is becoming an ever more popular sport worldwide with the trail running population having more than doubled since 2006. more and more people are moving from the monotonous and repetitive running nature of road running to the trails. with the popularity of trail running increasing, so are the number of injuries being reported. injuries range from acute to chronic and include muscular, skeletal, ligamentous and tendinous. the amount of time an athlete cannot train or compete due to injury depends on its severity. this study aims to investigate the prevalence and type of injuries of trail runners in south african trail runners aged between 19-40 years. methods: this study will employ a descriptive, survey research design involving the use of a questionnaire sent to various trail running groups or clubs, which will be used to collect specific data from the runners. the sample will include male and female trail runners from the ages of 19-40 years from both recreational to elite level, who have at least 2 years of running experience. an information sheet, explaining the study and what the participant will be asked to do, will be sent via email to various trail running groups and clubs across the country to distribute to their members. participation will be purely voluntary and a link will be provided, via the running club, to the google form questionnaire. by completing the questionnaire, consent will be implied. the sample size is dependent on the amount of respondents. descriptive statistics will be utilized to analyse the data. in doing so, the type of injury and prevalence thereof will be established. results – this study data has not be collected yet, but we aim to do this by august this year, so the study will be complete in time for presentation at the conference in october. 35 o08: the effect of a three month hopsports brain breaks® intervention programme on the attitudes of grade 6-learners towards physical activity and fitness. 1jacqueline bonnema1, 1dané coetzee & 1anita lennox 1physical activity, sport and recreation, faculty of health sciences (phasrec) focus area, north-west university (potchefstroom campus), south africa. presenting author e-mail address: jackie.bonnema@nwu.ac.za introduction: negative attitudes towards physical activity (pa) have been reported to have an influence on the pa levels of children and the choices they make to be physically active or not. research also indicated that children’s pa levels are more prevalent to decline between the ages of 12to 15-years. this study investigated the effect of a three month hopsports brain break® intervention programme on children’s attitudes towards pa and fitness. method: attitudes towards pa were assessed by means of the attitudes towards physical activity scale (apas) questionnaire in children between the ages of 11to 12-years. the experimental group consisted of 75 children (44 boys and 31 girls) with a mean age 11.4 years (±0.54) and 39 children (12 boys and 27 girls) for the control group with a mean age of 11.71 years (± 0.49). results: the results indicated that there were no significant differences between the two group’s attitudes towards pa and fitness with the pre-test. however, after the intervention programme there was a significant difference with a large effect size (d ≥ 0.8) which includes the attitudes towards the benefits of pa (α = .70; d = 1.13), importance of pa (α = .65; d = 0.63), self-perception of physical fitness (α = .86; d = 0.77) and their attitudes towards support in the environment and their interest for pa (α = .83; d = 1.25). conclusion: recommendations from this study are that more focus should be on 12-year old children because the decline in pa levels is more prevalent and their attitudes are more influential as well as to create opportunities where children can be equally active. 36 o09: workload does not impact performance responses in the indian premier league cricket lee pote, devon barnard, catherine munro, dave goble, belinda campbell, candice christie human kinetics and ergonomics, rhodes university, grahamstown, south africa movement physiology research laboratory, school of physiology, wits university, johannesburg, south africa presenting author e-mail address: introduction: elite cricket is an international sport dominated by three main formats, namely test, one day and most recently, t20 matches; each with its own workload requirements. the performance aspect of the game is of particular importance in bowlers, who are essential to a team’s success as they restrict the opposition’s runs and attempt to bowl them out. as a result, better bowling performance results in improved overall team performance and an increased chance of winning. research has shown that bowling requires players to perform multiple quick actions simultaneously, which can increase the physical demands placed on the body. thus, an increase in workload may have an effect on a player’s bowling performance; which is of a particular concern with an increase in the amount of competitions that are currently being played globally. the indian premier league started in 2008 and has been ongoing since then, with the prize money for the winning team in 2018 being four million dollars. the aim of this investigation was to determine the relationship between bowling performance and player workload in elite indian premier league bowlers. methods: the sample consisted of eleven male, professional cricket bowlers (mean ±sd, 27 ± 5.61 years; stature: 1.77 ± 0.07 m; mass: 72.09 ± 10.89 kg) currently playing for a team in the indian premier league cricket competition. both bowling disciplines (seam and spin) as well as all-rounders were considered for the investigation. workload data was obtained using microzone data capturing software and was reduced into total weekly workload and total cumulative workload. the match was gathered from espn cricinfo. match data included; overs bowled, runs conceded, wickets taken, bowling economy, dot balls bowled, 4's conceded, 6's conceded, wides bowled. the performance data and match data were used to establish relationships between workloads and performance related data. results:no significant relationships were found between total weekly workload and performance. conversely, cumulative workload did have an impact on some performance measures. specifically, the total cumulative workload of weeks 1 to 4 had a strong negative association (r = 0.89) with total overs bowled in the fourth match week (p=0.041). in addition, total cumulative workload of weeks 1 to 7 had a strong positive (r = 0.83) relationship with the total number of 6’s conceded in match week 7. no other relationships were observed. conclusion: the most important finding of the investigation is that workload does not predict performance in this indian premier league cohort of bowlers. however, associations were observed between total cumulative workload and specific measures. this may be due to the fact that the nature of the game of cricket is exceptionally unpredictable and t is challenging to measure performance related responses. 37 o10: influences of early perceptual-motor proficiency, gender, overweight and socioeconomic status on academic achievement of primary school children: longitudinal data of the north-west child study de waal e1*, pienaar ae1, ellis sm2 1physical activity, sport and recreation (phasrec), focus area, faculty of health sciences, potchefstroom campus, north-west university, potchefstroom, republic of south africa. ²unit for business mathematics and informatics, north-west university, potchefstroom, republic of south africa. *current address: department of exercise and sport sciences, faculty of health sciences, university of the free state, bloemfontein, south africa. presenting author e-mail address: dewaale@ufs.ac.za introduction: perceptual-motor proficiency and academic achievement is considered to be fundamentally intertwined. excessive body weight might provide and additional burden to this reported link, while socio-economic status (ses) and gender are also reported to influence academic achievement. this study aimed to determine how perceptual-motor proficiency, gender, overweight and ses are related to academic achievement longitudinally. method: the study included 381 participants (181 boys; 200 girls, 168 high ses; 218 low ses) that formed part of the nw-child longitudinal study covering the primary school period of 7 school years, starting at grade 1 (6.86 years, ± 0.39) in 2010 until grade 7 (12.9 years, ±0.38) in 2016. the bruininks oseretsky test of motor proficiency-2 (bot-2) short form and selected composites were used to assess perceptual-motor proficiency at baseline and at two follow-up time-points, while provincial and mid-year academic school reports determined academic achievement. results: correlation analyses confirmed significant moderate (r = .19 to r = .36) correlations between perceptual-motor proficiency at early and older ages and academic achievement. normal weight children demonstrated practically significant better strength, balance and running speed and agility. a latent growth curve analysis for academic achievement within structural equation modelling (sem) were tested, and indicated prior academic achievement, socio-economic status and gender as the strongest long-term determinants, while persistent overweight/obesity did not influence academic achievement significantly. perceptual-motor proficiency correlated with grade 1 academic achievement and showed an indirect relationship to grade 7 academic achievements via academic performance in grade 4. academic achievement in grade 1 and ses had the largest effect on both academic achievements in grade 4 and in grade 7, according to the standardised regression weights and total effects. boys and participants with lower ses had lower academic achievement at ages 9 and 12. conclusion: influences that should be addressed timeously include academic achievement in grade 1 and ses, which had the largest effect on both academic achievement and perceptual-motor proficiency, especially in the earlier grades. 38 o11: a nine-week pilates exercise programme reduces pain in the upper body of female office workers kimberly-ann decina1*, paola s wood1, steve olorunju2 1department of physiology, faculty of health sciences, university of pretoria, pretoria 0002, south africa. ²biostatistics unit, south african medical research council, private bag x385 pretoria 0001, south africa presenting author e-mail address: kdecina@outlook.com introduction: the increase of pain prevalence in the upper body of female office workers due to prolonged visual display unit (vdu) work is a growing socioeconomic concern amongst employers. associated risk factors include poor posture, static muscle contractions and being female. pilates focuses on improving body awareness and movement and has shown to be useful in the treatment of chronic lower back pain. thus, the study aimed to determine the effects of the pilates method of exercise on pain and functionality of the neck, shoulders and/or upper back in female office workers in pretoria. methods: an experimental, pre-test post-test control group design was used. female office workers between 30-55 years (n=60) performing ≥4hrs of vdu work per day with pain in their neck, shoulders and/or upper back, volunteered for the study. participants were randomly assigned to a control group (cg) (n=30) or experimental group (eg) (n=30), using the fishbowl technique. the eg completed 18 pilates sessions over nine weeks. baseline and post-intervention measurements included pain prevalence (nordic musculoskeletal questionnaire); pain intensity (visual analogue scale); scapular stability (lateral scapular slide test), neck and shoulder range of motion (rom) and shoulder strength (microfet3 digital inclinometer and dynamometer). statistical analysis included paired t-tests, unpaired t-tests and effect sizes. results: at post-test the eg reported a reduction in pain prevalence in the neck (46.67%, p<0.001), shoulders (66.67%, p<0.001) and upper back (33.33%, p=0.002). baseline pain intensity values averaged at 5.4, with a significant 33.3% (p<0.001) decrease following the intervention. the most restricted roms were neck rotation, neck lateral flexion, shoulder flexion, shoulder abduction and shoulder internal rotation (ir). significant post-intervention improvements were noted in neck flexion (p=0.008; d=0.07), neck extension (p=0.004; d=0.13), neck lateral flexion (p<0.001; d=0.75 left, d=0.90 right), neck rotation to the right (p=0.014; d=0.59), shoulder extension (d=1.03 left, d=1.01 right), left shoulder flexion (p=0.001; d=0.33), shoulder abduction (p=0.013 left; d=0.91 left, d=0.77 right) and left shoulder external rotation (er) (d=0.62). shoulder flexion, extension and abduction strength values were below the norms at baseline. the pilates intervention significantly increased left shoulder flexion (p=0.048; d=0.18), shoulder extension (d=0.82 left, d=0.89 right), right shoulder abduction (p=0.018; d=0.12), shoulder ir (d=0.79 left, d=0.84 right), shoulder er (p=0.010 left; d=1.36 left, d=0.45 right). scapular instability at baseline improved significantly (p<0.001) at post-test. conclusions: the pilates intervention successfully reduced upper body pain prevalence and intensity; increased neck and shoulder rom and shoulder strength with variable clinical significance; and improved scapular stability. evidence supports the pilates method of exercise to be included in corporate wellness programmes. 39 o12: tackle and ruck technique proficiency within academy and senior club rugby union den hollander, s1-3, lambert, m1-2, jones b1,4-8, hendricks, s1-2,4 1 division of exercise science and sports medicine, department of human biology, faculty of health sciences, the university of cape town and the sports science institute of south africa, cape town, south africa. 2 health through physical activity, lifestyle and sport research centre (hpals), faculty of health sciences, the university of cape town, south africa. 3 western province rugby academy, cape town, south africa. 4 carnegie applied rugby research (carr) centre, institute for sport, physical activity and leisure, leeds beckett university, leeds, uk. 5 yorkshire carnegie rugby union football club, leeds, uk. 6 leeds rhinos rugby league club, leeds, uk. 7 england performance unit, the rugby football league, leeds, uk. 8school of science and technology, university of new england, nsw, australia. presenting author e-mail address: steve_dh1989@hotmail.com introduction: this study examined the validity of a tool that assesses tackle and ruck technique in training, and established reference data for tackle, ball-carry and ruck technique at different levels of play in rugby union. methods: one hundred and thirty-one amateur rugby union players; 37 senior, 51 first grade academy and 43 second grade academy players, participated in a two-on-two contact drill. the drill was filmed and the players’ tackle, ballcarry and ruck technique were assessed using standardized technical criteria. one-way analysis of variance was used to test for differences between the levels (senior, academy 1st and academy 2nd) and cohen’s effect sizes were used to calculate the magnitude of these differences. results: senior level players scored significantly higher in all three assessments; tackle technique senior vs academy 1st (p<0.01, es=0.7, moderate), senior vs academy 2nd (p<0.01, es=0.7, moderate); ball-carry technique senior vs academy 1st (p<0.01, es=0.6, moderate), senior vs academy 2nd (p<0.01, es=0.8, moderate); ruck technique senior vs academy 1st (p<0.01, es=0.7, moderate), senior vs academy 2nd (p<0.01, es=0.4, small). discussion: these findings emphasize the importance of developing contact technique to allow players to progress to higher levels, and provide validity to an assessment tool which can facilitate this process. 40 o13: associations of physical activity levels and engaging in substance use and other mental health risks among american youth kele ding1, jiangzhen yang2 1school of health science, kent state university, kent, ohio, usa; ²center for injury research and policy, dept. of pediatrics, college of medicine, the ohio state university, columbus, ohio, usa. presenting author e-mail address: kding@kent.edu introduction: regular physical activity has been recognized as an effective strategy in reducing the risk of many adverse health consequences. the benefits of physical activity significantly increase through higher intensity, greater frequency, and/or longer duration of physical activity. however, whether individuals who are physically active are more likely to engage in other health-related behaviors remain unclear. the purpose of this study is to investigate whether physically active youth also engage more in other health-related behaviors. method: the youth risk behavior surveillance system (yrbss) combined data set was used as a basic data source. physical activity level was defined by a question asking about the number of days in past 7 days prior to the survey that youth has engaged in a total of 60 minutes or more of physical activity. the responses on physical activity level were categorized into three comparison groups: 1) 5 or more days a week, 2) one to four days a week, or 3) none. a series of substance use and mental health disorders were selected for examination. presence of each of these behaviors/disorders was treated as a dichotomous variable. sampling unit was used as cluster variable, and population weight score was used to weight each case. generalized linear modeling with gee adjustment was used to test the odds of each behavior among the physical activity categories. sex, age, race, grade, and gpa were included in the analysis as control variables. significance was defined at p < 0.05. results: a total of 14,238 youth who answered the physical activity question on the 2017 yrbss were included, while 527 with missing values were excluded. of 14,238 youth, 7,329 (51.5%) were females and 6,789 (47.7%) were males, with an average age of 16 (ranging from 12 to 18 years). more than 40% (43.8%) of youth reported 5-7 days per week of physical activity for 60 min or longer, followed by 39.3% of youth who reported one to four days per week of physical activity. however, 16.9% of youth reported 0 days of physical activity in the past week. after adjusting for demographic variables, youth who were more physically active tended to have higher odds of engaging in the risk behaviors. significantly higher odds were found for tobacco use, steroid use, and marijuana use; drinking driving or riding with a drunken driver. youth who were physically active were less likely to experience feelings of sadness or hopelessness, and less likely to attempt suicide. conclusion: physical activity is recommended for youth. however, less than half of youth in the study sample met the recommended activity level. relatively, youth who were more physically active had higher odds of engaging in drug use behaviors but lower odds of reporting mental health-related disorders. the results of this study suggest the importance of promoting mental health-related behaviors while promoting physical activity among youth. 41 o14: end of season evaluation of coaches by athletes (eseca) of the university of the philippines dizer, r1, santelices oys² 1department of physical education university of the philippines, diliman, quezon city, philippines. ²department of sport science, university of the philippines, diliman, quezon city, philippines. presenting author e-mail address: ronniedizer@yahoo.com introduction: sports coaching is a complex job that it needs to look into the many details involved in this profession rather than to use these outcomes in competitions to measure and evaluate coaching performance. the aim of the research is to construct an instrument that would enable coaches identify their self-awareness of their own coaching and teaching skills as perceived by the athletes in 29 collegiate sports events with 3 performing dance groups under the university of the philippines’ varsity sports program. methods: this test development utilized test construction methodology to arrive at its objective in coming up with the end of season evaluation of coaches by athletes (eseca) consisting of the use of likert scale and open-ended questions. the researchers did expert validation by getting experts in test construction from the college of social science and philosophy of the university of the philippines. based from their comments and suggestions, the researchers did item analysis to come up with a validated through face validity. results: these procedures resulted in the construction of the initial draft of the end of season evaluation of coaches by athletes (eseca) with the following concepts: 1. coaching principles/philosophy, 2. organization/administration, 3. coaching methodology, and 4. overall evaluation. comments and suggestions were also included in order to have a subjective evaluation of the coaches. conclusions: with the eseca, this can already be used as a pilot study by administering it to the athletes of the university of the philippines to evaluate the coaches of their respective sports. and future research can be done if there is a need to improve the eseca. 42 o15: teacher perceptions of learner motivation after the completion of a physical education in-service training programme du toit, d¹, van der merwe, n², oelofse, v³. 1physical activity, sport and recreation (phasrec) research focus area, faculty of education, north-west university, south africa. ²physical activity, sport and recreation (phasrec) research focus area, faculty of education, north-west university, south africa. ³faculty of education, north-west university, south africa. presenting author e-mail address: dorita.dutoit@nwu.ac.za introduction: the shortage of trained and qualified physical education (pe) teachers in south africa is worrying, in view of the decline in physical activity and the associated increase in health risks among south african children, which can be addressed by effective pe. the competence and effectiveness of the pe-teacher can also have a positive effect on the motivation levels of learners to participate in pe and physical activities. in-service training programmes aiming to improve the competence, effectiveness and needs-support skills of pe teachers, can therefore indirectly enhance the motivation levels of learners in the pe class. the purpose of this study was to investigate the effect of an in-service training programme on learner motivation, as perceived by their teachers. methods: the study was based on qualitative research within the theoretical framework of the self determination theory (sdt) of deci and ryan (2000), which postulates the satisfaction of the basic psychological needs of autonomy, competence and relatedness for determining intrinsic motivation. individual interviews were conducted with eight purposefully chosen participants in a five-day, in-service pe teacher training programme, on the last day of the programme and four months later. qualitative data were also collected from open-ended questions, and supported by limited quantitative data from questionnaires. categories and themes were identified and interpreted according to specific steps and guidelines, while the quantitative data were analysed using descriptive statistics. results: the first theme that emerged strongly from the qualitative data reflected that the participants experienced higher levels of learner motivation after the training programme. the reasons for these improved motivation levels were categorized as four subthemes, all relating to the psychological needs of the learners. firstly, the teachers ascribed their learners’ improved motivation to their implementation of new and creative ideas for practical activities. secondly, learner motivation was influenced by the higher levels of selfconfidence, competence and motivation of their teachers, which strengthened the learners’ perceptions and understanding of the value of pe. thirdly, according to the participants, the discouraging impact of too few or no pe equipment was overcome by their newly acquired knowledge and skills to improvise apparatus. the participants further felt that their improved competence and effectiveness to meet the needs of large and diverse pe classes, impacted on learner motivation, and that all pe teachers should receive specialized training in this regard. the second theme involved barriers that still impacted negatively on learner motivation, which also included large and diverse classes, unqualified and unenthusiastic teachers, a lack of support from principals and colleagues, and poor facilities. the quantitative results supported the above findings. conclusions: according to the findings, the in-service training programme contributed to enhanced learner motivation, based on the satisfaction of learner needs by pe teachers within the sdt framework. similar in-service training programmes can therefore make a positive contribution to learner motivation in pe and physical activities, and indirectly to the promotion of pe and child health in south africa. 43 o16: a 15 year historical journey of dietary/nutritional product assessment in south africa consequence opportunity progress excellence gary gabriels department of pharmacy and pharmacology, faculty of health sciences, university of the witwatersrand, johannesburg, south africa, presenting author e-mail address: gary.gabriels@gmail.com introduction: dietary/nutritional supplement legislation and regulation in south africa, and elsewhere, is usually embedded in other forms of legislation rather than a standalone entity. the constitution of south africa sometimes obliges, parliament to legislate on certain commodities. the rapid increase in supplement sales and consumption in south africa can be attributed to aggressive marketing by manufacturers whose claims are not always supported by published peer-reviewed evidence. the situation is further exacerbated by pressure placed on certain groups to use supplements, such as sports people, both those in their development phase to the those who are competitive, the recreational user, and extending to the elderly. as a consequence the supplement industry has grown to meet the increasing demand. these supplements may contain adulterated substances that may potentially have harmful short and long-term health consequences. the regulation of the supplement industry is unrefined, which increases the risk of the nutritional supplements being contaminated. contamination may be intentional, where the companies ‘spike’ their products with an ergogenic aid, or unintentional. as a result of poor regulation, contaminants or adulterants in supplements may also cause insidious effects unrelated to the listed ingredients. the aim of this paper is to present a historical trajectory and impact of the research over the defined period. methods: selected papers which formed the basis for research into dietary/nutritional supplements will be covered. results: the results will focus on selected aspects of dietary/nutritional supplements , related to, consumer protection, labelling information, gymnasium users attitude, protein essences ‘melamine’, antidepressant fluoxetine, trace element and heavy metals, and the role of health and wellness provides, linked to consequence, opportunity, progress and excellence to the overall research project. conclusions: the research platform provides opportunity for interdisciplinary, transdisciplinary, multidisciplinary, research and academic collaboration and co-operation. further, the findings over this period provide sufficient evidence for a way forward to implement a system of improved regulating, monitoring and enforcing the quality control of dietary/nutritional supplements in a more assertive way. that health and wellness providers should have or develop an explicit understanding for the potential adverse effects related to dietary/nutritional supplements, including drug-supplement interactions. 44 o17: practical approach of sport injuries prevention – a romanian perspective luminita, georgescu university of pitesti, faculty of sciences, physical education and informatics, targu din vale, romania presenting author e-mail address: kinetopit@yahoo.com introduction: with the continuous increase in the number of practitioners, currently there is also a significant increase in the risk of injury due to sport activities, whether they is for performance or leisure. continuous adaptations and improvements of the equipment, of the training techniques and regulations are some of the concerns that specialists in the field of sport do have in respect with the prevention of specific injuries. methods: health status screening, medical forms and certificates to approve sports participation are some of the methods used by the sports medicine staff to prevent injuries and the risk of injury. we used a retrospective longitudinal study and analyzed the medical records of 1200 athletes (300 playing individual sports and 900 practicing sports games) over a period of five years. through a structured interview we gathered data of the athletes’ health status and also their injury records during training and competition. we were interested also to range the athletes’ characteristics depending on their anthropometric measurements and physical development, clinical and paraclinical examinations and aerobic and anaerobic exercise capacity. our aim was to identify the biological profile of athletes at high risk of injury and the correlation of individual sanogenic factors with the sport’s requirements, respectively the training stage. starting from this, we wanted to project an intervention strategy, based on a combination of methods to increase the fitness level, pharmacological treatment, hygiene-dietetic measures and physiotherapy programs. results: after processing all data, some injury-associated risk factors were identified: deficiencies in the athletes’ selection by sports branches; inconsistency between the physical development of the athletes and the sport requirements; paucity of the body’s ability to adapt to the physical effort according to the stage of sports training. conclusions: there is a close correlation between the initial clinical and paraclinical assessment and then the periodical assessment in determining the athlete's health status and his effort adaptation ability. moreover, the correction of biochemical imbalances has a special role in preventing the risk of injuries. 45 o18: the possible effects of biological maturation on the physical activity levels of 12-13 year-old boys and girls barry gerber barry gerber, anita pienaar north-west university south africa1 gerber.barry@gmail.com introduction: research on the relationship between physical activity, maturity, health and quality of life has been thoroughly researched worldwide on adults, although research on this topic has been less priority in terms of children and adolescents. current literature indicates that boys’ and girls' physical activity decreased on average by 10% and 15% respectively as they get older. to investigate the current state of physical activity of 12-13 year old boys and girls and to determine the possible relationship between biological maturation and physical activity level of both gender methodology: a convenience sample (586 participants, 303 boys and 283 girls) with a chronological age of 13.07 years from 20 selected schools in the northwest province, south africa was used. physical activities and biological maturation data was obtained through a physical questionnaire and anthropometric measurements. descriptive statistics was used to determine means, minimum, maximum and standard deviation. independent t-test was used to compare gender differences. one way anova with a tukey post hoc adjustment was carried out to determine significant differences between maturation groups and effect size was calculated by cohans d-formula. results: boys and girls showed similar anthropometric characteristics with boys on average being taller, heavier and showing a taller sitting height. early maturating groups on average contained taller and heavier participants in both genders accept for late maturating girls being the heavier group. various statistical (p0.05) and small to medium practical (0.2d0.53) significant differences were found between genders physical activity levels, with boys showing higher physical activity levels throughout. on average small to medium correlation (0.1r0.57). apart from two variables in the group of girls no other statistical significant (p>0.05) intergroup differences regarding physical activity were found. conclusion: physical activity levels at 12-13 years of age does not differ considerable between genders although boys perform better than girls. maturity however does play an important role in boys’ and girls’ physical activity at this age especially in boys due to them entering the puberty phase. 46 o19: creating a holistic university wellbeing strategy that connects and inspires staff and students steve gibling director wellness and sport services, university of canterbury, new zealand presenting author e-mail address: steve.gibling@canterbury.ac.nz introduction: in 2017 the university adopted a wellbeing framework that amongst other things adopted an aotearoa new zealand focused model of interpreting wellbeing at the university of canterbury (uc). in early 2018 the university also adopted the wellness, physical activity and sport strategy: te rautaki tākaro me te hauora. whilst both strategies were unique, and created a platform to strategically discuss wellbeing on campus, both strategies failed to acknowledge the role of staff in wellbeing, or their own wellbeing needs as independent but equally important players in a tertiary wellbeing approach. both also failed to truly address the bicultural aspirations and requirements of mana whenua (indigenous population of new zealand). in late 2018 a plan was established that would create a new wellbeing strategy which would: take account of more information related to student and staff mental health; address some of the gaps in the framework and strategy; re-engage with the student and staff population of uc and connect with allied partners in the community associated with health, wellness and wellbeing. this presentation will focus on the current wellbeing approach at the university of canterbury, addressing why certain aspects of wellbeing strategizing have and have not worked and what uc are doing about it. in particular, the move to the use of an indigenous and holistic well-being model that will permeate every policy and practice across the university by being adopted as a part of the organisations overarching academic strategy. further developments include the alignment to the governments approach to wellbeing as a nation’s stance, with specific alignment to the united nations sustainable development goals, recognising the importance of sport and active lifestyles in well-being and post disaster response. ultimately this is all evidenced based and a research and reporting programme is being developed that connects the internal goals right through to front line service delivery 47 o20: the effect of law changes on match loads in university rugby union players during the fnb varsity cup gordon gr¹ morris-eyton h1, kubayi a2 1department of human and movement studies, university of johannesburg, doornfontein campus, south africa; ²department of sport, rehabilitation and dental sciences, faculty of science, tshwane university of technology, pretoria, south africa. presenting author e-mail address: greg4gordon@gmail.com introduction: rugby union is a sport which is played at a high intensity making it appealing for spectators to watch. law changes have been implemented to make the sport more competitive, create continuity in the sport, enhance player safety and to improve the enjoyment factor for the players and spectators. fnb varsity cup rugby have endeavoured to be innovative by introducing new law variations and strives to make a difference in sport. the aim of this study is to determine the effect that the law changes implemented in the fnb varsity cup rugby during 2016 till 2018 had affected the players’ external load during match play. methods: this study followed a longitudinal retrospective quantitative research design using secondary data from a university rugby union team. a total of 61 players’ external match load was captured on the catapult optimeye x4 micro-technology devices. the data was analysed and compared to each season’s data with reference to the law changes implemented during each season and match influencing factors such as match outcome, match location and quality of opponent. the tests done for the results of this research include independent t-tests, anova, two-way anova and tukey hsd post-hoc analysis. results: the players’ total distances, high speed running distances and playerload were more affected compared to other variables during the three seasons. the front row forwards covered the most distances in 2016 (4317±2017m) when compared to the other seasons, while the back row forwards had higher running distances in 2017 (4554±1787m) and 2018 (4426±1924m) than in 2016. with regards to the inside backs, their distances were predominantly largest in the 2017 season (5566±1852m), whereas the outside backs ran larger distances in the 2018 season (6337±737m). conclusions: the back line players ran larger total distances than the forwards did during match play. additionally, when separating the players into position specific groups, they differed in which year they ran more. it is evident that the running metrics of the players varied between each season analysed. this may indicate there is a difference between the seasons because of law variations introduced or amended. 48 o21: social capital development through the songo.info cycling, academic support and life skills programme: programme leader and participant perspectives 1neely cw, 1grobbelaar hw 1department of sport science, faculty of medicine and health sciences, stellenbosch university, south africa. presenting author e-mail address: hgrobbelaar@sun.ac.za introduction: the songo.info cycling, academic support and life skills programme based in kayamandi, stellenbosch aims to develop confident, well-rounded, gainfully employed individuals who contribute to the community. development through sport programmes is a popular tool to enhance social capital (the network of relationships that surround an individual), and plays an important role in marginalized societies in assisting the youth to complete school, develop transferrable life skills, enter the job market etc. methods: this study explored the development of social capital through this programme from the perspectives of five programme leaders (m age: 40.6 years, range: 27-72 years) and nine current and past programme participants (m age: 18.3 years, range: 15-24 years), who took part in semi-structured individual interviews. the elicited information was analysed through qualitative content analysis utilising manual, open and negotiated coding. the authors collectively grouped the agreed-upon codes into various categories of codes, subthemes and themes.results: the three themes (and subthemes) were: 1) education (world experiences, furthering education, and access to resources), 2) networks (social skills, personal relationships, and professional relationships), and 3) holistic development (physical, social and emotional domains). conclusions: the network of relationships established through involvement with the programme appears to positively impact the everyday life of both the programme leaders and participants. furthermore, the educational and holistic development seems to enhance the social mobility of the programme’s participants. 49 o22: kinematics and muscle activation in adolescent tennis players with and without lower back pain immelman ee¹, olivier b¹ 1physiotherapy department, faculty of health sciences, university of the witwatersrand, presenting author e-mail address: @gmail.com, introduction: injury in athletes can cause long periods away from active training and if not addressed correctly, may lead to recurrent injuries or chronic pain. the most powerful and strenuous stroke in tennis is the serve. motor control is crucial during a force-generating stroke such as the tennis serve. motor control is the result of a harmonious co-activation relationship between different muscle groups. the aim of this study was to compare the muscle activation and three-dimensional joint angles of the lower trunk and hips during the different phases of the tennis serve in adolescent tennis players with and without lower back pain. methods: this study used a cross-sectional, observational design involving junior tennis players. physical testing incorporated three-dimensional motion analysis (inertial measurement system) and wireless surface electromyography during the tennis serve. a total of six service motions were recorded and used for analysis for each participant. kinematic analyses of the lower trunk and bilateral hips were conducted. the rectus abdominis, external obliques, erector spinae and gluteus maximus muscles were evaluated during the tennis serve. the mannwhitney u test was used to determine statistically significant differences between independent variables. a pearson bivariate correlation analysis and binary logistic regression model determined which of the variables was the strongest at predicting whether a participant would be categorised into the lower back pain (lbp) or no lower back pain (nlbp) groups. results: a total of 33 adolescent tennis players from the north gauteng tennis club participated in this study. the sample comprised of 21 participants in the nlbp group and 12 participants in the lbp group. the logistic regression displayed three key points that could assist in the identification of risk factors for lbp during the tennis serve. firstly, a smaller angle of hip flexion (start point or=0.75; ball release point or=0.62) and external rotation (ball release point or=1.406; loading point or=0.866) during the preparation phase; secondly, a greater degree of adduction (final point or=0.533), internal rotation (final point or=1.252) and flexion (final point or=1.269) of the hip during the deceleration phase; thirdly, the importance of correct muscle activation of the anterior trunk and control throughout movement during the loading point of the preparation phase (rectus abdominis or=0.645; external obliques or=1.101) and final point of the deceleration phase (rectus abdominis or=1.537). conclusions: the kinematic-related key points emphasise the importance of force transfer over a stable base of support. the muscle-activity key point emphasises the importance of muscle strength and the global stability functional testing. an evaluation of the tennis serves showed that the two groups displayed different preparation and execution strategies. the identification of variables that have an effect on lower back pain status could play an important role in the prevention of injury and in rehabilitation programmes. the three key points need to be kept in mind in the treatment and training of adolescent tennis players. 50 o24: anterior knee pain, risk factors and impact on the quality of life among runners in under-resourced communities, ekurhuleni siyabonga henry kunene1,2, serela ramklass2, nomathemba patricia taukobong3 1physiotherapy department, university of the witwatersrand, johannesburg, south africa. 2school of clinical medicine, university of kwazulunatal, durban, south africa 3institutional planning department, sefako makgatho health sciences university, pretoria, south africa. presenting author e-mail address: siyabonga.kunene@wits.ac.za, introduction: anterior knee pain (akp) is the most problematic symptom among many runners. due to poor rehabilitation services in under-resourced communities, runners are likely to report poorer health outcomes compared to other communities. various factors predispose runners to akp making a holistic rehabilitation inevitable. the purpose was to determine the presence of akp & risk factors & its impact on the qol among runners in in under-resourced communities, ekurhuleni. methods: this was a cross-sectional study. convenient sampling was used to recruit participants aged between 13 & 55 with no history of knee surgery, traumatic or degenerative knee conditions. prevalence of akp and its risk factors were determined among 183 participants. qol was determined among 73 participants who presented with akp. data collection tools included: kujala questionnaire for akp prevalence, developed questionnaire for extrinsic risk factors, 12 physical screening tests for intrinsic risk factors & sf-36 questionnaire for qol. ethical clearance, permission from 6 clubs & consent from participants were obtained. the spss was used to analyse data. results: 40% of participants presented with akp. akp was associated with age (x2=6.484, p=.04) & running experience (x2=8.389, p =.04). the following risk factors contributed significantly to akp: tight hamstrings (or=1.02; p =.05); tight iliotibial band (or=1.1; p =.05); weak quadriceps (or=.15; p =.04); weak hip muscles (or=1.13; p =.00) & patellar tilt abnormalities (or=1.33; p =.01), years of running experience (or=1.72, p=.05), endurance training (or=1.83, p =.05) & downhill running (or=1.88 , p=.04). the lowest sf-36 mean scores were found in 2 health domains: role limitation due to emotional problems (59) & vitality (59). highest scores were found in the general physical functioning domain (72). females presented with lowest scores (48) on role limitation due to emotional problems with noticeable difference (p=.03). youth presented with lowest scores (62) on the social functioning domain (p=.00). significant differences were noted on sf-36 scores between running experienced groups on the following domains: physical functioning (p=.03), role limitation due to physical problems (p=.01), vitality (p=.00), general mental health (p=.00) & social functioning (p=.00). the most affected was the group with 3-5 years of running experience which presented with scores ranging between 46 & 65. significant mean differences were also noted between bmi groups in the social functioning domain (p=.01) where overweight & obese groups were mostly affected by akp. conclusions: a substantial presence of akp & its risk factors were found among participants. these outcomes suggested that intrinsic & extrinsic risk factors should be considered when managing akp among runners. this study also highlighted a need to also address non-physical features, such as the psychosocial, emotional & mental factors when formulating strategies to improve qol among the running population. a multidimensional community-based rehabilitation programme is therefore recommended to prevent and rehabilitate akp among runners. 51 o25: rehabilitation approaches to anterior knee pain among runners: a scoping review siyabonga henry kunene1,2, serela ramklass2, nomathemba patricia taukobong3 1physiotherapy department, university of the witwatersrand, johannesburg, south africa. 2physiotherapy department, university of kwazulu-natal, durban, south africa. 3institutional planning department, sefako makgatho health sciences university, pretoria, south africa presenting author e-mail address: siyabonga.kunene@wits.ac.za, introduction: anterior knee pain (akp) is the most common clinical presentation among athletes accounting for 15 45% and it presents a threat to their quality of life. causes and management of it remain controversial due to the lack of consensus among clinicians and researchers. the evidence for rehabilitation strategies among runners with akp is limited and scatted. therefore, the purpose of this study was to map the range of non-surgical and nonpharmaceutical rehabilitation approaches to akp among runners. methods: a scoping review was conducted. the five stages that were followed are: 1) defining the research question; 2) identifying relevant studies; 3) selecting a topic for the study; 4) charting and collecting the data; 5) summarising and reporting the results. included in the study, were the original articles, written in english, included articles looked at rehabilitation strategies for akp among runners prior to november 2017. six electronic databases were searched, namely ebscohost, cinahl, sportdiscus, pubmed, cochrane, and scopus. results: thirteen (13) out of 1334 articles met the inclusion criteria. two reviewers independently participated in the screening and extraction of articles. the identified articles included 4 rcts, 1 systematic review, 4 observational studies, 1 cohort study, 2 case studies and 1 quasi experimental study. the following rehabilitation strategies were found to be useful in rehabilitating runners with akp: education (on symptoms and management of akp), gait re-education (hip control, forefoot strike pattern), exercise (strengthening, stretching), foot orthoses (medially wedged insoles) and multimodal rehabilitation (combination of modalities including gait retraining, lower limb strengthening exercises, core strengthening exercises, motor control exercises and advices). conclusions: this study has provided a range of rehabilitation strategies which were found useful in the prevention and rehabilitation of akp. anterior knee pain is a multifactorial condition that require a comprehensive but yet individualised management approach. therefore, more comprehensive intervention studies are needed to address all the physical and non-physical needs of runners with akp. the outcomes of this study make explicit the usefulness of the identified rehabilitation strategies among runners with akp. these will guide clinicians in the development of rehabilitation programmes for runners. 52 o26: education for leisure and the use of comic books in physical education classes cinthia lopes da silva silvio rossi filho, ana carolina capellini rigoni, luciene ferreira da silva, priscilla pinto costa da silva, gisele maria schwartz presenting author e-mail address: introduction: the rates of school dropouts are high in brazil, mainly in the last years of junior high school. most students dislike physical education classes because of content repetition, unsatisfactory curricular organization, among other factors. the problem gets worse when research data about the practice of physical activities by brazilians show that a significant number of people do not get involved in any type of physical activities in their spare time (45,9%). this problem related to the access of people to physical activities in brazil is due to matters relating to public policies of sports and leisure as well as the experiences those people had during their lives, which did not contribute in any way to the habit and/or enjoyment of activities such as sports, games, dancing and so on, which are elements that could have been practiced in their spare time throughout their lives. in addition to the biological consequences, there is a loss, which is often overlooked, and it is related to the lack of development of knowledge about the body and other cultural elements of bodily movement, which can lead people to a lack of understanding of themselves, their own sensitivity, their own emotions which can be felt and manifested through their bodies. therefore, it is necessary to gather elements and methodological resources in order to motivate students to develop a liking for knowledge at school, and specially, for physical education classes, which will make them willing to participate in the proposed bodily experiences from the physical activities. it is necessary to bring to class the topic of physical activities and the construction of comic books can be a strategy to deal with presented data about the school failure and the percentage of people who do not have any kind of physical activities incorporated in their daily routines. this work has the objective of executing, describing and assessing the efficiency of a proposal for physical education classes, which include various contents of bodily culture of movement and the use of comic books. methods: both bibliographic and field researches were carried out and this is a qualitative study. ten classes were given to a group of ninth graders from a public school in the city of piracicaba/sp/brazil. results: the results show that the use of comic books as a teaching resource is powerful in that the experiences they had were felt and mediated through their “rational” and “sensitive” knowledge about physical activities and comic books. the pedagogical experiment made possible for the students of this investigation the education for leisure, the awakening to the enjoyment and knowledge about elements of the bodily culture of movement and the access to some of the leisure contents presented here, mainly by the physical, sporty and artistic, and also by the experiences in class and the construction of comic books. this work is part of a research sponsored by fundação de amparo à pesquisa do estado de são paulo (fapesp)/brazil, process 2017/13279-4. 53 o27: experiences of young south african gymnasts, parents and coaches about the health benefits of sport participation lucas, wc1,2, titus, s3 and young, m1 1department of sport, recreation and exercise science, university of the western cape, cape town, south africa. 2alcohol, tobacco and other drugs research unit, south african medical research council, cape town, south africa. 3interdisciplinary teaching and learning unit, school of public health, university of the western cape, cape town, south africa. presenting author e-mail address: warren.lucas@mrc.ac.za introduction: gymnastics, as a physical activity, presents young people with opportunities to learn physical skills, improve eye-hand coordination, develop gross and fine motor skills, and socially develop through engagement with other young people. an understanding of aerobic and anaerobic physical activities is important to enhance young people’s physical, emotional, cognitive and social development. methods: this study investigated the perceptions of a purposively sampled group of young people in the western cape of south africa about the health benefits of gymnastics participation, and reported findings from the perspectives of registered competitive gymnasts, gymnastics coaches, and parents of gymnasts (total n=34), with specific reference to the domains of physical, cognitive and socio-emotional development. a qualitative approach based on the process-person-context-time (ppct) concept, adapted from the bioecological model, was used as the theoretical framework to underpin, analyze and interpret findings of the study. four key informant interviews were conducted with four coaches, and five focus group discussions were held with gymnasts, parents of gymnasts and gymnastics coaches. results: thematic analysis of the participants’ responses indicated the following themes as health benefits and opportunities for children’s development through gymnastics participation: socio-emotional development with respect to positive attitude shifts, respect of peers and coaches, and physical development concerning musculoskeletal growth. conclusions: development of strength and flexibility were also found to be positive contributors to child development. additionally, improvements in cognition which could positively influence children’s academic achievement and the learning of new movement skills, were also attributed to gymnastics participation. the implications of the findings for children’s holistic development was discussed. 54 o28:physical activity and selected sociodemographic variables as predictors of nutritional knowledge amongst an adult south african sample of low socioeconomic status smart mabweazara1, sunday onagbiye2, lloyd leach2, lungiswa tsolekile1, thandi puoane1 1university of the western cape (school of public health) south africa ²university of the western cape (department of sport, recreation and exercise science) south africa presenting author e-mail address: smabweazara@googlemail.com introduction: nutritional intake contributes to human health and well-being, and plays a pivotal role in human growth and development. one factor that plays a pivotal role in the quality of an individual’s diet is their nutritional knowledge (nk). the aim of this study was to determine if physical activity (pa) and selected sociodemographic variables (gender, educational level, and employment status) predict nk amongst an adult south african sample of low socioeconomic status (ses). methods: a cross-sectional study of 319 randomly sampled adults with a mean age of 57 (±10.43) years, who participated in the prospective urban rural epidemiological (pure) study were purposively sampled for data pertaining to nk, pa, educational level and employment status using a semi-structured, researchergenerated questionnaire. linear regression analysis was used to test predictive relationships with alpha level set at p 0.05. results: the results showed that for persons of low socioeconomic status, engaging in pa was a significant predictor of nk (p 0.05), when controlling for educational level and employment status. the model explained 4.6% of the variance on nk. conclusions: in conclusion, engaging in pa was a significant predictor of nk for persons of low ses. public health practitioners are encouraged to develop interventions that that promote pa as a means to enhancing nk. interventions should be specifically aimed at persons of low ses who are more prone to engaging in sedentary, health-compromising behaviours. additionally, care should be taken to contextualise the interventions for persons of low ses, so that they fit into the socioeconomic and cultural frame of reference of the participants. 55 o29: guidelines for leadership development using leisure education for youth with disabilities in south africa. malema makhaya1 , wegner lisa2 and young marie 1 1department of sports, recreation & exercise science; university of the western cape, south africa. ²department of occupational therapy2. university of the western cape, south africa. presenting author e-mail address: mmalema@uwc.ac.za introduction: life transition occurs to everyone when they assume new roles in their lives; this may also cause a change in leisure behaviour. life transitions can be in a form of interventions, hence, the south african government encourages a national and global intervention that would see people with disabilities being included in mainstream society activities. the latter advocates equal opportunities, living independently, having education, employment, and social integration. however, equal opportunities for people with disabilities have not been achieved due to unbalanced and inadequate resources in communities. the current study is aligned to the national development plan, and proposes that through leisure education, youth with disabilities will increase and sustain their leisure knowledge, make their own opportunities for leisure and become independent to their own social needs; thus developing leadership. therefore, the aim of the study is to gain an understanding of leisure education as a tool for leadership development among youth with disabilities, in order to develop guidelines for use in the south african context. methods: using a sequential explanatory mixed methods approach, this study will consist of a systematic review, quantitative cross sectional design and a qualitative descriptive design. the study will include eight centres for physical disabilities in cape town, with participants aged 18-34 years. the combined population for youth with disabilities at the eight centres is 150, therefore, by applying slovin’s formula, the sample size for this study is 109. a random and stratified sampling method will be used to recruit participants for the study. the stratifying characteristics for the sample are gender (male and female), age, and physical disability. phase 1 of this study is a systematic review which addresses objective 1, which is to investigate how leisure programmes have been used to develop youth leadership among youth with disabilities. phase 2 of this study, addresses objective 2: describe how youth with disabilities’ perceive leisure education and leadership development. phase 3 of the current study addresses objective 3 which seeks to explore how leisure education can be used as a tool to develop leadership among youth with disabilities. phase 4 will integrate finding from phase 1-3 to develop guidelines for leadership development among youth with disabilities using leisure education as a tool. data collection methods include the leisure education survey developed by sivan, a youth leadership development questionnaire developed by eikenberry, and semistructured interviews. data will be analysed using quantitative and qualitative methods, and the findings will be integrated to develop guidelines for leadership development through leisure education. conclusions: this study will provide insight on how to empower youth with disabilities, by providing youth leadership through leisure education. throughout, this study, participants will be exposed to, and learn, varied skills which can be applied in their daily lives into mainstream society. through skills learnt and opportunities presented to participants in this study, there is a potential outcome for transformation among youth with disabilities. this study also adds to development and promotion of a growing capacity of youth with disabilities, developing leaders working together in solving a complex national problem. 56 o30: perceptions of adapted physical education services through the lens of asian parents mcclain z1, bridges d2, bridges e3 1department of kinesiology, california state university, east bay, hayward, ca, u.s.a.. ²school of kinesiology & nutritional science, california state university, los angeles, los angeles, ca, u.s.a. ³benjamin & yancy foundation, inc., new orleans, la, u.s.a. presenting author e-mail address: zanean.mcclain@csueastbay.edu introduction: parents’ perceptions may be viewed through a narrow lens that could possibly be impacted by cultural context, personal beliefs, limited knowledge, and lack of awareness of educational services (jeong, kim, & lee, 2015; lai & vadeboncoeur, 2013; lee & park, 2016). school personnel and parents lack the development of a partnership to determine how resources for students with a disability can be effectively utilized for programming (an & hodge, 2013; hamlin & flessa, 2018; lee, dillon, & stewart, 2019). this study aimed to identify asian parents’ perceptions on adapted physical education services delivered to their children with disabilities in school environments. the study highlighted both positive and negative aspects of various experiences encountered by asian parent participants with regards to programming and services. methods: this study utilized a qualitative research design (creswell, 2013) approved by an institutional review board and participant consent. participants were fifteen parents with a child with a disability receiving direct services (including adapted physical education) at an educational institution and were recruited from a community-based parent support program. the investigators utilized a bilingual semistructured questionnaire, which consisted of open-ended questions, to ensure capturing the rich data of the participants. the questionnaire was validated by experts for content validity. an interpreter was used to certify the full understanding of the parents’ written explanations, when necessary. content validity was supported with field notes taken by the investigators during the each interview. major themes were identified through independent coding of participant responses as well as, through field notes that were derived from the investigators. results: the semi-structured questionnaire, analysis, and field note depiction led to identifying four major themes as participants consistently expressed perceptions within these broader categories. these four themes consisted of 1) the lack of understanding about parents’ cultural differences, 2) the lack of goal setting for the adapted physical education curriculum, 3) limited knowledge of parental rights, and 4) noted barriers to services experienced. the information gathered from the participants resulted in a greater understanding of their cultural differences. conclusions: the study examined the importance of asian parents’ perceptions of direct school services for their children with disabilities. it is important to understand that special education services can be perceived differently based on specific cultural beliefs. this research has provided an opportunity to better understand cultural perspectives and provided necessary recommendations to bridge the gap that may exist between an educational institution culture and asian parent culture regarding special education services. these recommendations consist of forming collaborative partnerships in schools, providing direct support for parents to continue advocating for their children, increasing the need for school personnel to understand the asian culture, and enhancing parental training (e.g., policies and practices of special education) through the educational system. continued research should be conducted to broaden the scope of goals to overcome perceived barriers within any culture for children with disabilities to perhaps increase the quality of their movements and daily life activities. 57 o31: association between physical activity levels and body fat percentage in 6-8 year-old children from a black south african population: bc-it study makama andries monyeki1, caroline m sedumedi1 1physical activity, sport and recreation research focus area, faculty of health sciences, north-west university, potchefstroom, south africa presenting author e-mail address: andries.monyeki@nwu.ac.za introduction: obesity and physical inactivity are global health problems in children and adults alike, with developing countries experiencing a shift from mortality predominately driven by infectious diseases to mortality driven largely by non-communicable diseases (ncds). the aim of the study was to determine the association between objective measured physical activity (pa) levels and body fat determined by stable isotope and bioelectrical impendence analysis (bia) in 6–8-year-old children from a black south african population. methods: participants are a total of 96 children (53 girls and 43 boys; mean age of 7.7±1.23) who are part of a larger cross-sectional study aimed at determining body composition using stable isotope technique (bc-it). body mass index (bmi) was calculated as weight in kilograms divided by height in meters squared. body fat percentage was assessed using stable dilution techniques (d2o) and bia (bodystat 1500 mdd). actigraph accelerometer (model gt3x-bt) determine pa for a minimum of 10 hours/day for seven consecutive days. pa data was then categories into sedentary pa (<99 counts per minute), light pa (≥ 100 counts per minute), moderate pa (≥2296 counts per minute), vigorous pa (≥ 4012 counts per minute) and moderate to vigorous pa (mvpa). descriptive statistics and independent sample t-test for gender difference were performed by spss program. correlation coefficients (r) were used to determine the relationship between physical activity and body composition. results: prevalence of overweight/obesity for the total group using d2o was 22% and 13% by bmi and respectively; with 12% and 11% being underweight and with girls (33%) being more overweight/obesity than the boy (7%). girls were significantly (p=0.03) more sedentary (356.14±48.66 min/week, girls’ vs 325.41±49.38 min/week, boys) and fatter (7.26±3.29kg) compared to boys (5.44±2.43kg). boys spent significantly (p<0.05) more time in moderate and vigorous pa (48.80±13.44 min/week) than girls (65.84±15.16±15.16). objective pa levels (moderate, vigorous and mvpa) were inversely associated with fat mass as determined by stable isotope (r= -0.27, p=0.01, r=-0.27, p=0.01 and r= -0.27, p<0.05) and bia (r= -0.27, p=0.01; r= -0.29, p<0.05 and r= -0.30, p<0.05). conclusions: girls were more overweight and sedentary compared to their boys’ counterparts. additionally, it was evident that excessive fatness negatively affected the children participation in physical activity. given the health implications of these results, urgent strategic interventions are recommended. 58 o32: measuring physical activity in south african grade 2 and 3 learners: a self-report questionnaire versus pedometer testing 1nolte k, 1malan gf 1division: biokinetics and sport science, department of physiology, sport, exercise medicine and lifestyle institute (semli), faculty of health sciences, university of pretoria, south africa presenting author e-mail address: introduction: the prevalence of childhood obesity is increasing in south africa and can be linked to decreased physical activity (pa). it is therefore important to be able to accurately measure children’s pa levels as part of a holistic strategy for maintaining healthy body weight. methods: the primary aim of this study was to determine whether children in grades two and three can self-report pa by means of a questionnaire. fifty-eight participants (28 females, 30 males) from a primary school in gauteng were recruited for the study. the participants had to wear a pedometer (omron hj-720) for seven days after which they completed the physical activity questionnaire for older children (paq-c). results: the average steps per day were 9289, with weekday steps (10 219) being more than weekend steps (6795). the mean score for the paq-c was 3.14 ± 0.47. there was a significant moderate correlation (r = 0.49; p < 0.01) between the overall paq-c score and average steps per day. conclusions: therefore, the paq-c can be an effective way in which to gain insight into pa levels in children but should not replace objective measures of pa. the participants in this study appear to be accumulating insufficient pa over the course of the week. 59 o33: perceptions of physical activity participation among university students living on and off campus in the western cape. 1simamkele nyangiwe, 1tshegofatso mgwambane & 1makhaya malema 1department of sports, recreation and sport sciences, university of the western cape, south africa presenting author e-mail address: 3970067@myuwc.ac.za introduction: universities are said to have a responsibility to offer a holistic education and should, therefore, include ways to prevent risky behaviours, such as sedentary living. as university students are expected to make informed decisions about their future endeavours, it is suggested that physical activity be prioritised and be part of their autonomous decisions. physical activity plays a significant role in the mental and emotional well-being of an individual, for example, depression. literature notes that 23% of adults and 8 % adolescents’ do not meet world health organizations’ global recommendations on minimum physical activity for general health promotions. it is noted with concern the increase of people living a sedentary and inactive lifestyle. furthermore, world health organization suggest that as countries develop economically, simultaneously, there is a noticeable decline in physical activity due to improved technology, mode of transportation, urbanisation and cultural values. interestingly, a multi-racial study notes that students from asian and african countries have the lowest levels of physical activity participation, whereas, white students are the most physically active. methods: purpose of the study is to explore the perceptions of physical activity participation among students in the university of western cape. the study will use a qualitative ethnographic design to collect data from participants using semi-structured one-onone interviews. purposeful sampling method will be used to select 8 participants for the study to collect data. the study interviews will be a minimum of 30 minutes, which, will be recorded using a digital recorder and transcribed verbatim. open coding will be applied when analysing the transcribed data through atlas.ti software programme. trustworthiness of the study will be accomplished using credibility, transferability, dependability and conformability methods. the study will seek permission to collect data from the university of the western cape research ethics committee. participation in this study will be purely voluntary, and participants will be advised that should they wish to withdraw from the study, this will be allowed without prejudice on the study. the study will not publish participants’ personal details, and in cases of names, pseudonym names will be used in place of participants’ names. results: the current study is ongoing, however, it is noted that as lifestyle changes during the university period are sustained into adulthood, students tend to engage in risky behaviours such as alcohol and tobacco use, physical inactivity, which can lead to long term negative implications for their health and poor perceptions about their body structure. this study look to explore and identify the importance of physical activity participation among university students of the university of the western cape. conclusions: the benefits of physical activity include improved health, life satisfaction and quality of life, social relations, community cohesion, sense of community and sense of achievement. furthermore, individuals are recommended to engage in physical activity, from moderate or vigorous intensity exercise, 3-5 days a week to experience the benefits of physical activity. 60 o34: an investigation of the association between vitamin-d receptor gene bsmi polymorphism, bone health status, and muscular performance in malay young female athletes and non-athletes foong kiew ooi 1, abu bakar nor azara1, chee keong chen1, ravindran ankathil2, ahmad aizat abdul aziz2 and jamaayah meor osman1 1exercise and sports science programme, school of health sciences, universiti sains malaysia, health campus, kelantan, malaysia. ²human genome centre, school of medical sciences, universiti sains malaysia, health campus, kelantan, malaysia. presenting author e-mail address: fkooi@usm.my introduction: this study investigated the association between vitamin-d receptor (vdr) gene bsmi polymorphism, bone, muscular strength and power in malay young female athletes and non-athletes. methods: sixty malay females aged between 15-17 years old were involved. there were 2 groups in this study: (i) athletes group with state level athletes (n=30), and (ii) non-athletes group with non-active individuals (n=30). participants’ knee and shoulder isokinetic muscular peak torque (strength) and average power were measured using isokinetic dynamometer. hand grip strength test was performed. participants’ tibial and radial quantitative ultrasound measurements of bone speed of sound were measured using bone sonometer. whole blood was collected for dna extraction purpose. genotyping of vdr gene bsmi polymorphism was performed using polymerase chain reaction-restriction fragment length polymorphism (pcr-rflp) method. chi-square test, independent t-test and one-way anova were used for statistical analysis. results: in athletes, bb genotype was associated with higher bone speed of sound in the arm compared to bb genotype, while bb genotype was associated with higher bone speed of sound in the leg compared to bb genotype. in nonathletes, bb genotype was associated with higher handgrip strength compared to bb genotype. it was also found that bb genotype was associated with greater knee isokinetic extension and flexion peak torque per body weight (strength) compared to bb genotype. bb and bb genotype were associated with greater shoulder isokinetic flexion peak torque (strength) compared to bb genotype in non-athletes. conclusions: the present study findings imply that vdr bsmi bb and bb genotypes are associated with better bone health status in malay young female state level athletes. vdr bsmi bb and bb genotype are also associated with greater muscular strength in malay young female non-athletes. 61 o35: effect of a 12-week aerobic exercise programme on percentage body fat, fasting blood glucose and dyspnea in insulin resistant, obese female university employees in the western cape. 1phatlane phindile, 1susan bassett, 1sunday onagbyiye 1department of sports, recreation & exercise sciences, university of the western cape, south africa presenting author e-mail address: introduction: obesity is recognised as a risk factor for non-communicable diseases (ncds) which has reached epidemic proportions globally, and south africa as one of the developing countries with significant statistical representation reported for this condition. obesity is associated with other conditions such as type 2 diabetes, hypertension and dyslipidemia which are all part of what is called metabolic syndrome. as a strategy to reduce the levels of obesity, physical activity has been introduced in the health care professions to compliment clients who are on medications for diabetes. this study seeks to investigate the effects of a 12-week aerobic training programme on percentage body fat and fasting blood glucose levels in insulin resistant, obese females uwc employees in the western cape. methods: the study utilised a quantitative approach using a pre-test post-test design with an intervention of an aerobic exercise programme for 12 weeks. the study included 20 females who are obese (i.e. bmi > 30 kg�m-2with a waist circumference >88cm) and who have fasting blood glucose levels >5.5mmol�l-1). participants informed prior to the commencement of the study that participation is purely voluntary, and should they chose to withdraw from the study, they can do so at any time without any penalties or lose any benefits to which they otherwise qualify. ethics clearance was obtained from the biomedical research ethics committee of the university of the western cape ethics number bm17/8/11 and participants were asked to give written consent before taking part in the study. results: it was hypothesised that a 12-week aerobic exercise programme will reduce the percentage of body fat, blood glucose and dyspnea in insulin resistant obese female university employees in the western cape. this study adds to the current body of knowledge and literature, furthermore, this study lays down a foundation for south african stakeholders and health care practitioners to implement this programme and effectively get the country moving through pa. conclusions: supervised aerobic exercise, when executed and implemented correctly, can safely decrease fatigue levels, weight, bmi, subcutaneous and abdominal girth to their participants, however no evidence from the results suggest improvements on dyspnea. 62 o36: perception of athletes between coaches’ behaviour and athletes’ motivation on selected collegiate table tennis athletes ssibal, jie 1, santelices, oys2 1university of the philippines integrated school, diliman, quezon city, philippines. ²department of sport science, university of the philippines, diliman, quezon city, philippines. presenting author e-mail address: oskies@yahoo.com introduction: the study determined the relationship of perceived coaches' behaviour and athletes' motivation. among selected table tennis athletes of the university athletic association of the philippines (uaap). methods: selected athletes from the eight(8) uaap schools completed the 7-point likert scale of sport motivation scale (sms) and 5-point likert scale of leadership scale for sports. these were utilized to determine the motivation of athletes and perceived leadership displayed by the coach. descriptive statistics and pearson chi-square were used to determine the relationship of coaching behaviour and athletes' motivation. mannwhitney u and phi-coefficient were used to analyse the relationship of other variables (age, gender, number of playing years and year level) on perceived coaching behaviour. results: the result showed that democratic coaching behaviour has significant effect on athletes' motivation namely (to know-im, to accomplish-im, and identified-em). this result indicates that a democratic coach supports the athletes' enjoyment in training and discovering new techniques increases its intrinsic motivation which will be an aid for the improvement not only for the performance of athlete but as an individual. meanwhile, the autocratic coaching behaviour showed no significant results between athletes' motivation and perceived coaching behaviour, thus, it suggests that having a coach that is controlling, one who imposed a military style of behaviour during training or competition blocks the opportunity of an athlete to have fun in trying out specific skills and/or enjoy new discoveries of techniques, change in character, change of career opportunity, or even quit from sports. in addition, there were other factors that were considered in this study such as age, gender, number of playing years and year level. these variables showed insignificant results on relationship of perceived coaching behaviour. conclusions: the problem of coaches' behaviour in relation to athletes' motivation can be minimized with numerous foreign studies regarding it. the study proves this process will take a combination of time and effort on the part of coaches and athletes. the researchers believed that further investigation may contribute to the development or enhancement for both athletes and coaches 63 o37: preparing recreation professionals: graduate attributes expected of entry-level recreation professionals in a south african context cm. schreck1, tj weilbach1 and gm reisma2 1physical activity, sport and recreation, north-west university, potchefstroom campus, south africa;. 2centre for health professions education, north-west university, south africa. presenting author e-mail address: cornelia.schreck@nwu.ac.za introduction: the current unemployment rate of graduate students in south africa 7.3% an increased by more than 4% in the past 10 years. this increase can be ascribed to the economic situation of the country, but more important is the youth’s lack of work experience and absence of the skills and competencies (also known as graduate attributes) demanded by employers, reducing their suitability for employment. the focus of this study was to determine the graduate attributes required in entry-level recreation professionals in south africa. methods: a rankingtype delphi study design was used, consisting of three iterations. ten experts from the public, non-profit and private recreation sectors whose organisations employ entry-level recreation professionals were asked to rank the graduate attributes most required in students, and evaluate the relevance of graduate attributes for a south african context. data were analysed using descriptive statistics and inductive coding. results: “passion for the profession”, “trainability and a willingness to learn” and “communication skills” were the top-ranked attributes. clear differences were found in the expectations from south african graduates compared with united states graduates. “creativity”, “ability to work with groups” and “conflict management” were added for the south african context. conclusions: these results clarified what is expected of graduates entering recreation careers in sa, and it is therefore crucial that institutions preparing recreation students focus on these attributes in their programmes to enhance graduate employability. furthermore, students need a way to put their classroom knowledge to practice, to gain self-confidence and feel prepared for their initial employment in the field. it is therefore suggested that the experiential learning students are exposed to during their degree is expanded. 64 o38: metabolic controls and prevalence of depression symptoms: effects of sixteen weeks recreational football on male students tomar, r1, antony vc1 1physical education department, king fahd university of petroleum & minerals, dhahran, saudi arabia. presenting author e-mail address: rtau@rediffmail.com introduction: there is a relation between activity and health profile and mortality from the cardiovascular diseases. this is well known fact documented that physical activity affect positively several lifestyle-related diseases and cardiovascular risk factors. one of the major health problems of this century is physical inactivity. any exercise programme must be enjoyable so that it can be successfully incorporated into person’s lifestyle. football is associated with high-energy expenditure.4 if used as tool for physical conditioning, the smallsided games of football are very helpful in eliciting heart rate up to around 90–95% of maximal heart rate. present study investigated effects of sixteen weeks of recreational football on metabolic controls and prevalence of depression symptoms in untrained males. methods: thirty five male students were selected randomly from king fahd university of petroleum & minerals (kfupm) with mean age 18.75 yrs. participants were randomly assigned to three groups. group one was six a side football group (sfg, n = 12), group two was four a side football group (ffg, n = 8) and third was control group (cg, n = 15). sfg and ffg were intervention groups. three subjects from control group didn’t report for post-test. intervention group played recreational football for 16 weeks. football sessions were conducted on 40x30m outdoor artificial pitch. training sessions were organized twice a week. each session was divided into two halves of 15 minutes with 5 minute recovery. heart rate in intervention group was monitored during all football sessions using polar ft7. control group subjects followed their regular routine. one way anova was employed to find difference between the groups after 16 weeks of football. level of significance was set at .05 results: one-way anova revealed significant difference in very low density lipoprotein (p = 0.005), low density lipoprotein (p = 0.001), total cholesterol (p=.002) and triglycerides (p= .000). significant differences were also seen in hba1c (p=.000) bonferroni post hoc test revealed significantly lesser mean (5.20±0.15) in ffg than sfg (5.39±0.13, p= .000). fasting blood sugar also reduced significantly (p=.000) bonferroni post hoc test revealed significantly lesser mean (80.91±4.35) in sfg than cg (81.20±4.71, p= .016). ffg also had significantly lesser mean (76.87±4.88) than cg (81.20±4.71, p= .000). . while no significant improvement was observed in high density lipoprotein (p = 0.750). symptoms of depression were also reduced (p= .035). conclusions: findings of the present suggests that recreational football training with six and four sided teams appears to be effective in bringing change in metabolic controls in untrained males. sixteen weeks of supervised recreation, football training was effective in reducing fasting blood glucose. hba1c reduced significantly in both sfg and ffg group post 16 weeks. significant reduction was seen total cholesterol and low density lipoprotein in both sfg and ffg groups. our training was vigorous in nature as indicated by high average heart rate during the training sessions. further, recreation football could not affect high density lipoprotein significantly. there was also reduction in depression symptoms. 65 o39: the influence of a mindfulness-acceptance-commitment intervention program on the mental toughness, self-efficacy and anxiety of male league softball players in south africa. tsebe, kb1, van niekerk, rl2 1 department of psychology, university of fort hare, alice campus, south africa .2 department of human movement science, university of fort hare, alice campus, south africa. presenting author e-mail address: introduction: sport psychologists and researchers have been examining the influence various psychological factors such as mental toughness, self-efficacy and anxiety on the performance of players. the aim of this study was to explore the influence of a mindfulness-acceptancecommitment (mac) intervention program on the mental toughness, self-efficacy and anxiety of male league softball players. the prediction was that there is be a significant effect on the three constructs measured. methods: a purposive sampling of 2 teams randomly assigned to an experimental (n = 9) and control group (n = 8) from 2 different provinces, representing 17 players with a mean age of 20 years was invited to participate in the study. players in the experiment group received a 7 weeks mac intervention program, while the control group did not. the data was obtained using the sport mental toughness questionnaire, rosenberg selfesteem scale and sport competition anxiety test. the effect of the mac program was determined with non-parametric statistical test. results: the study found that the players who were involved in the mac program maintained their appropriate levels of anxiety, self-efficacy and mental toughness throughout the competition, while the players in the control groups anxiety, self-efficacy and mental toughness was eroded during that time. the mental toughness of the experimental group, was significantly higher than that of the control group at post-test stage. conclusions: the hypothesize was partially confirmed because the mac program made a significant difference in the mental toughness of the two groups, but not the self-efficacy and anxiety of the control and experiment group. 66 o40: shanghai amateur games: a hallmark sports event for residents yu weng college of physical education, soochow university, suzhou p.r.china presenting author e-mail address: wengyuivy@163.com introduction: a hallmark sports event tends to have positive influence on both the host city and its residents. shanghai amateur games is a series of games that is designed for residents in shanghai since 2017, and now it is trying to build its own “brand” and expand its influence. in this paper we discussed the features of the development process of shanghai amateur games. we also raised problems for its development. methods: we searched electronic databases, including cnki and google scholar, using the following keywords: hallmark event, sports event, sports management, branding, and cbbe model. we also searched the website of shanghai amateur games for official documents, including guidebook of 2019 shanghai amateur games and other files. we visited organizers of shanghai amateur games who interpret the development process of this hallmark sports event. we also designed a set of questionnaire and collected participants’ feedback of the games, with which we analysed participants’ attitude towards the games. results: with information from what we have gathered and the analysis of the documents we obtained, several features of the development process of shanghai amateur games are as below: residents in shanghai has began to create an impression on the “brand” of shanghai amateur games. different from famous international games held in shanghai such as f1 formula and shanghai atp 1000 which are facing professional athletes, it is a hallmark sports event that encourages local residents to participate in physical activities. after three years’ effort, shanghai amateur games is building a “brand” belonging to this city and meanwhile promote people’s participation in physical exercise. government is playing a significant role in the development process of building a hallmark sports event. by establishing an organizing platform, shanghai government has gathered series of amateur games that were once held spontaneously by communities or sports agents, providing them with fund and service. assessment mechanism is a dispensable part during the whole games development process. the assessment will evaluate the influence、 professionalism、and the social and economic contribution of each game. according to the assessment results, games are divided into three levels, and games in different level will get different fund and service support from the government. also, the assessment will collect participants’ feedback, evaluate its brand value and have an influence on the game’s future development. conclusions: shanghai is now building a hallmark sports event for residents. government and sports companies are working together to provide better service for residents and raise their awareness of physical activities. effectiveness is oblivious but problems also exist, such as participants’ consumption awareness during watching the games is still weak; capital resources for holding a game is limited; and games attraction to residents is not enough. 67 o41: leisure meanings of caregivers: a case study fouche a1, weilbach jt1, watson fg2 1physical activity, sport and recreation (phasrec), north-west university, south africa. ²quality in nursing and midwifery, north-west university, south africa. presenting author e-mail address: theron.weilbach@nwu.ac.za introduction: formal caregivers face high workloads, long working hours, staffing shortages, and emotional stress as burdens (rose & williams, 2015; whal & newmark, 2009; white, 2008). the responsibilities and heavy workload that caregivers face may lead to psychological and physical health problems like emotional exhaustion, distress and burnout, and have substantial impacts on a caregiver’s life, including his/her leisure lifestyle (brehaut et al., 2004; dupuis, 2000; hung et al., 2002). in this regard, dupuis and smale (2000) noted the changeability and contradictory nature of leisure meanings within an institution-based caregiving context, which indicates that the caregiving role may influence the meanings that caregivers attach to leisure. considering the possibility that leisure meanings can be formed based on individual reasoning within the context of social reality, as proposed by watkins (2000), it is possible that formal caregivers may attach unique meanings to leisure due to their caregiving roles. methods: this study made use of a qualitative approach based on an exploratory case study design. data were collected through semi-structured one-on-one interviews and aimed to explore the leisure meanings of formal caregivers caring for persons with disabilities in the north west province. the study population included formal caregivers employed at a full-time care centre from an under-resourced area in the north west province of south africa (n=25). from the population, data was gathered until data saturation was reached, resulting in twelve caregivers participating in the study, which is in line with recommendations by dick (2012). the interviews were audiotaped, then transcribed verbatim. microscopic examination was applied by going through the raw data to help with identifying words that might have different meanings to the participants or to identify different words that might have the same meaning to them (henderson, 2006). the data were then analysed by using atlas.ti as a computerised tool. information was coded and analysed into categories, themes and subthemes until certain patterns emerged. results: eight themes regarding caregivers’ meanings of leisure emerged, including (a) time they had free from responsibilities, (b) social interaction, (c) different forms of relaxation, (d) something they do out of their free will, (e) something that can take place or can be experienced anywhere or any time, (f) personal time or escape, (g) different forms of activities they like to participate in, and h) leisure as a positive experience. from the interviews, it also became apparent that these eight themes are influenced by the participants’ caregiving roles. although not directly related to leisure meanings, an additional result that emerged was that some caregivers considered aspects of caregiving as leisure. conclusions: the findings indicate that, due to their caregiving roles, caregivers attach unique meanings to leisure. as understanding leisure meanings can play a crucial role in building theory regarding leisure and may lead to improved service delivery (schulz & watkins, 2007:477), these findings can be used a starting point for tailoring leisure services that are in line with caregivers’ leisure meanings. 68 o42: student feedback and effect on different training stimuli in physical education classes pacholek m king fahd university of petroleum and minerals, dhahran, saudi arabia presenting author e-mail address: mpacholek@post.cz introduction: student feedback is considered a significant source of the quality of the teaching process. provides information about their thoughts, feelings and opinions which can significantly enhance our understanding of the teaching-learning process. the main aim of this study was to investigate how students perceived different training stimuli implemented during the physical education classes and the secondary effects of these classes on their motoric and anthropometric abilities. methodology: the study utilized four resistance training stimuli such as isometric, working out on machines, aerobic exercise / hit, dynamic with equipment and aerobic training stimuli on university students. fourteen non-physically active male students from the king fahd university of petroleum and minerals (kfupm) were randomly chosen to act as subjects (single group) for the study (n=14; age=20.5 ± 1.5 years; weight=100.5 ± 26.42 kg; height=177.8 ± 6.45 cm; bmi=31.9 ± 8.68 kg/m2). the training period for the study was four days per week for four weeks. in one class (50’), two different stimuli (20’-aerobic runs together with coordination and 20’-strength training) was applied. measurement-testing and content analysis were used for obtaining data and for evaluating data a questionnaire, mathematical, statistical and logical methods were used. the wilcoxon-signed rank test was applied as statistical tool for interpretation of results from the motoric and anthropometric tests. results: based on the results from the questionnaire it was concluded that students enjoyed and liked the aerobic stimuli the most as they had to exert less effort, but they also ranked them as the least effective. on the other hand the programs where they had to exert the most effort like the gym was ranked as the most effective but the least enjoyable. most of the students wanted to know more about dynamic training with equipment but from the general evaluation the least effective stimulus marked was static training and the most effective aerobic exercise/hit training. the sample showed significant improvement in all motoric tests: sit ups (19.1 ± 4.8 vs 23.1 ± 4.4), sit and reach test (18.2 ± 8.2 vs 23.4 ± 10.0cm), 5x10m shuttle run (16 ± 2 vs 14 ± 1s) and standing long jump (153.1 ± 20.7 vs 171.9 ± 23.9cm). anthropometric tests showed no significant change. except for visceral fat rating (9.8 ± 7.3 vs 9.5 ± 7.1), the other indicators stayed the same: bmi (31.9 ± 8.7 vs 31.8 ± 8.4 kg/m2), fat % (27.3 ± 9.9 vs 27.9 ± 9.4) and muscle mass (66.9 ± 10.2 vs 66.8 ± 10.0 kg). conclusion: this study provides valuable information into how more training stimuli can be effectively applied to physical education classes and how kfupm students perceived different training stimuli. from these results we can assume that students are looking for a balance between fun and hard work. e d ito rial journal of the south african sports medicine association olympic issue the growth and international acceptance of sports medicine owes much to the modern olympic games.1 the first significant event was the creation of the international olympic committee(ioc) medical committee in 1964 with the express responsibility of controlling drug use in olympic competition. the work of that committee focused global attention on our profes­ sion and its role in contemporary issues in international sport. ° more recently that committee has been respon­ sible for selecting the first recipient(s) of the ioc olympic prize which honours scientists with a lifetime of exceptional achievement in the sports sciences. this award, perhaps the equivalent of a nobel prize in the sports sciences, will be bestowed on professors ralph paffenbarger and jerry morris prior to the start of this year’s atlanta olympic games, and will further enhance the stature of the profession before a massive global audience. professor ralph paffenbarger has been a friend of south african sports medi­ cine for many years; he spoke at our international congress in cape town in 1989 and has complet­ ed both the two oceans and comrades marathons, the latter when he was well into his sixties. the work of these two visionary giants has established that physical inactivity is a major fac­ tor for coronary heart disease and also contributes to the aetiology of a number of other diseases including hypertension, diabetes and cancer of the large bowel. it is appropriate that the olympian life work of these two great gentlemen of the sports sciences should be appropriately recognised; their work proves the value of physi­ cal activity and provides the intellectual anchor which our professional credibility is secured. the second olympic event that has helped in the growth of the sports sciences was the quite dramatic rise to dominance of the eastern german democratic republic(gdr), in olympic competition. during the 1968 olympic games, the first games in which the gdr competed as a team separate from west germany, their athletes won 25 medals. in the 1988 olympic games, athletes from that country won 102 medals, one more than the total medal count for athletes from the united states, a country with a population almost tenfold larger than that of the gdr. other nations perceiving that this success resulted from a more “scientific” and professional approach to sport in the gdr, began to investigate ways in which science could be profitably applied for the enhancement of human sporting performance. of the commonwealth countries, australia and per­ haps to a lesser extent canada, have taken the lead in these developments. the third important factor was the holding of the 1968 olympic games at mexico city at an alti­ tude of 2270m . never before had the olympic games been held in a city so high above sea-level! this single event first exposed, on an internation­ al scale, the very embarrassing inadequacies in our knowledge of some quite basic issues in the applied spoils sciences. for at that time, the real effects of medium altitude on athletic perfor­ mance were simply not known. nor had the poten­ tial health risks associated with holing olympic competition at altitude been studied. many of the great exercise scientists of the modem era first cut their scientific teeth in the research of that question. i would suggest that analysis will show that it was after 1968 and the scientific stimulus provided by those olympic games, that our pro­ fession really took off. mindful of the importance of olympic games for our profession, it is appro­ priate that this issue of our journal should be devoted to sports medical issues of special rele­ vance to the olympic games. it is often useful to begin in the past. to set the scene, dr floris van der merwe reviews some of the great moments of south african achievements in olympic track and field competition. he reminds us that only 5 south african athletes have won medals in the olympic track and field competition. only one of those gold medals has been won since the second world war, suggesting that our international standing in international competition has fallen. he points out that politics robbed south africa of some of its greatest recent track and field athletes like sydney mare, mark plaatjies and freddie fredericks, world-class ath­ letes who might well have won olympic medals for south africa in the more recent olympic games. if political factors, since corrected, restricted our olympic potential in the past, i would suggest that the future success of our olympic athletes will require that they receive the best that our profession can offer, including our capacity for innovation. for analysis of the great olympic ath­ letes reveals that most were in the forefront of innovative training methods. the great finnish distance runners who dominated the early olympic games owed their success to the intro­ duction of distance training during the winter months.2 these methods were refined by paavo nurmi, one of the first runners to include regular speed training in his preparation. nurmi is con­ sidered to be the greatest olympian of all time.8 emil zatopck refined the techniques of speed training, winning a total of 4 gold medals at the sports medicine july 1996 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 1948 and 1952 o lym p ics in cluding the 4 2k m m arathon w hich he c o n s id e r e d the “ most borin g ra ce ” he had ever run! t h e next g reat furnish nuuier, lasse v iren, w on 4 g old m e d a ls in 1972 mid 1976 with th is in troduction o f the c o n c e p t o f racing infrequently and “ p e a k in g ” only for the o lym pic g a m es, a tech n iqu e also follow ed by frank shorter, g old and silver m ed a llist in the 1972 and 1976 o lym p ic m arathons respectively. w hat innovative training teclm iq u es will our a th ­ letes have follow ed in thenpreparation for the 1996 o lym p ic g a m e s ? t h e a rticles b y d rs j o h n h aw ley and h elg o s c h o m c r and ms. e lskc s ch abort review the p h y s­ iological and p sy ch olog ica l factors that con trib u te to the su cc e ss in international sp ortin g c o m p e t i­ tion. hawley and s ch abort review the prog ression o f w orld m im in g r e c o r d s and ask w h eth e r there are iden tifiab le ph y siological ch a n g es that might explain the p rogressive pattern o f im provem ent in th ese record s. t h ey c o n clu d e that the m axim um oxygen con su m p tion o f the m o d e m w orld record h o ld e r is not lik ely h ig h e r than that o f earlier re co rd h old e rs. r a th er the variable that has ch a n g e d , is the s p e cific en du ran ce w h ich is the cap acity to sustain a h igh p ercen tage o f the m axi­ mum oxygen con su m p tion for lon ger din ing c o m ­ p etition . factors that cou ld explain this ch an ge in clu d e im proved running tracks, com m e rcia lism , p r o fe s s io n a lis m , m ore n u m e ro u s c o m p e tit iv e opp ortu n ities, im proved nutrition, anti p erh ap s the use o f p h a m ia co lo g ica l agents in training. hi h is d e ta ile d yet practical article, dr h elgo s c h o m c r review s the p sych olog ica l preparation for o lym pic com p etition . h e b e g in s with the p rem ise that there are no physical d iffe re n ce s b etw een the very best a th le te s in any sport. r a th er th e w inner is the ath lete w h o is m entally the stron g est on the day o f com p e titio n . s c h o m c r id e n tifie s the four im portan t psych olog ical factors d eterm in in g s u cc e s s and d e s c rib e s the p s y ch o lo g ­ ical sk ills training p rog ra m m e s that are cru cial for d e v e lop in g th ose sk ills. h e su g g ests that sp ortin g su c c e ss c o m e s w hen th ese tech n iq u e s b e c o m e se c o n d nature. h e p ro v id e s appropriate g u id e ­ lin es for p sy ch o lo g ica l training and c o n c lu d e s that lifelon g practice is requ ired to p e r fe c t th ese m en ­ tal sk ills. o f co u rse, the value o f th ese mental sk ills ex ten d s b ey on d th e o lym p ic arena, to all levels, o f sp ort and to d aily life. but th e m ajor o lym p ic ch a lle n g e rem ain s the p rom otion o f fa n com p e tition by elim in atin g the u se o f p erform a n ce en h a n cin g d ru g s in clu d in g the a n abolic ste ro id s , ery th rop oeitin and grow th h o r ­ m one. d r g eo rg e van d ugteren o f the national ohtnpic c o m m ittee o f s outh a frica (n o c sa) has p re p a re d an a n ti-d o p in g p o lic y on b e h a lf o f nocsa and th e south a frican institute for drug free sport. t h is p o licy is r e p ro d u ce d h ere, as is th e la test(1 9 9 6 ) e d itio n o f th e ioc list o f bann ed drugs. t h is is crucial inform ation for all w h o treat or advise our o lym pic ath letes. a n oth er im portant sou rce o f th is inform ation, the m im s b o o k , p erm itted and b anned d rugs in s port has recen tly b e e n p u b lish ed b u t is p erh a p s not as w id ely known as m ight be h op ed . t h e a d d i­ tional value o f that pu blication is that it p rov id e s lists o f ban n ed and perm itted d ru g s a c co r d in g to th eir trade n am es. t h is allow s the ath lete and his or her m ed ica l con sidtan t to b e absolu tely certain o f the status o f any m ed ica tion available in south africa. t h e b o o k is available only from the m im s o ffice (po box 2 0 5 9 , pretoria, 0 0 0 1 : ph on e num ­ b e r 0 1 2 3 4 8 5 0 1 0 ). t h e issu e a lso in c lu d e s on e o f th e m ost th ou g h t-p rov ok in g a rticles on d ru g co n trol in sport that i have read. in h is article australian sp orts ph ysician dr m anuel c usi p o s e s three d if­ ferent scen a rios th at m igh t b e en cou n tered by any d o c to r treatin g a th letes. t h e first involves the p rescrip tion o f an a b olic ste ro id s or o th e r banned d ru g s bv d o c to r s a p p oin ted in an official capacity to sp ortin g team s. cusi argu es that such d o c to r s may not p re scrib e bann ed su b sta n ces to team m em b ers. t h e secon d scen a rio is p erh a p s m ore com m on and involves the p rescription o f an abolic s te r o id s for a th le te s involved in non com p etitive sports. again the eth ica l p ositio n taken by cusi is that su ch d ru g s sh ou ld not b e p re s crib e d by d o c ­ tors and the reasons for th is position are carefully argued. h is third scen a rio p resen ts the problem o f p rescrib in g m ed ica tion for the treatm ent o f legitim ate m ed ica l co n d ition in an ath lete w h o c o m p e te s in a sp ort in w h ich that sp ecific d ru g is b a n n ed . h is con clu sion m ay seem surprising. p erhaps h is m ost ch a llen g in g statem en t is that his th ree scen a rios “ in dicate that m ed ica l p ra c­ tice is m ore co m p le x than the io c ’s an ti-dopin g rationale a d m its .” long may th is d eba te con tin ue. s p ecial thanks are due to all oiua u th ors for th eir d ilig e n ce in sh arin g then* k n ow led ge and sp ecia lly to ou r a ustralian co lle a g u e s, dr c usi and d r p eter brukner, form er e d ito r o f s p orth ealth , w h o have given th eir p erm ission for the use o f d r c u si’s article. we w ish our a th letes and th eir m ed ica l su p port team all p o s sib le su c ce ss in the atlanta o lym pic g a m e s and h ope that th is issue o f ou r jou rn al will porten d a favourable ch an ge in s ou d i a frica ’s recen t a ch ie v em en ts in o lym p ic com p etition . editor professor tim noakes mrc/vct bioenergetics o f exercise research unit and liberty life chair o f exercise and spurts science, spurts sciencc institute o f south africa. buundary road. newlands, 7700, south africa. referen ces 1. noakes td. the olym pic gaines and sports medicine. british journal o f sports medicine. 2. noakes td. lore o f running. oxford university press. 1992. 3. johnson wo. h7io is the g rea test? time magazine, june 24tli, l996.pp68-89. pi 2 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) till* soi t i l a f k i c a w i o l ' k w i oi sports medicine volume 3 number 2 editor proftd noakes dr mp schwellnas editorial board dr m e moollu dr p de jayer dr j skowno dr p schwartz prof r stretch dr c de ridder prof b c and re ics dr e w dennan mr r h farman prof m mars dr c a noble international advisory board lyle j micheli associate clinical professor o f orthopaedic surgery boston, usa chester r kyle research director, sports equipment research associates california, usa pro) hc wildor hollmann prasident des deutschen sportarztebiuides kohi, west gennany howard j green professor, department of kinesiology' ontario, canada george a brooks professor, department o f physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke associate professor, biology’ department, university o f colorado colorado, usa graham n smith physiologist glasgow, scotland july 1996 c o n te n ts editorial td noakes onthullings oor suid-afrika se goue medaljes in atletiek fjg van der merwe the limits to human performance: a physiological perspective j a hawley ej schabort psychological preparation for olympic athletes h schomer nocsa anti-doping policy g ruijsch van dugteren south african institute for drug-free sport 13 18 23 doping and clinical practice: ethical perspectives 27 mf cusi the editor, the south .african journal o f sports medicine p o b o x 115, newlands 7725 production a ndrew t hom as publishing g lenbarr publishers ce private bag x i 4 parkjands 2196 tel: ( o i l ) 44 2-9 759 fax: ( o i l ) 88 0-7 898 advertising marike de w aal/andrew t hom as reproduction output reproductions printing hortors reparil-gel r elieves m u scula r pain editore' the adv^nr^>111 ^ lhc i*?rsonaj the authors and are not necessarily shared b v the ------------e ertlserb or ulc polishers. no articles may be reproduced yyitliout die written consent of the publishers. sports medicine july 1996 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) onthullings oor suid-afrika se goue medaljes in atletiek f j g v a il d e r m e r w e , d phil, departement menslike bewegingskunde, universiteit van stellenbosch abstract south african sport is back in the international arena and is doing quite well lately. this year is the centenary of the m odem olympic movement. south africa is hop­ ing to win a gold medal in the track and held athletics. so far only five south african athletes have succeeded in winning this much sought-after trophy. they were reggie walker (1908), kenneth mcarthur (1912), bevil rudd (1920), sid atkinson (1928) and esther brand (1952). with the exception o f esther brand, all o f south africa’s gold medals were won before the second world war. already in 1947 dr ernst jokl predicted that the african athletes would follow in the footsteps o f the scandinavian achievements. unfortunately ihe saaau put a colour ban on athletics as early as 1931. this, and the later apartheid policy, deprived many non-white athletes o f the opportunity to win a gold medal in the olympic games. keywords: south africa, olympic games track and field athletics. inleiding die springbokke is die wereld se rugbykampioen, die bafana bafana is afrika se sokkerkanipioen en die proteas het hul voete in intemasionale lcrieket gevind en gaan van krag tot krag. die lang droogte wat die beleid van sportisolasie jeens suid-afrika meegebring het, is iets van die verlede. vanjaar word die m odem e olimpiese spelebeweging 100 jaar oud en suid-afrika neem vir die tweede keer sedert 1960 daaraan deel. baron pierre de coubertin se olimpii'sme1 wat behels dat sport eerder karakter moet kweek as rekords najaag, was nog altyd net ’n clroom. wanneer daar van olimpiese helde gepraat word, is die silweren brons medaljewenners van minder belang die held(in) 1)1 j nou eenmaal die persoon wat die hoogste plek op die rostrum ingeneem het. h ierdie prestasie het suid afrika slegs tussen 1908 en 1952 te beurt geval. dit will tans voorkom asof suid-afrika ’n goeie kans op ’n goue medalje in atlanta in atletiek sal he. in retro speksie het suid-afrika van 1908 tot 1960 en in 1992 slegs vyf al l etiekprestasies opgelewer wat goed genoeg was om ’n goue medalje te verower. daar sal in die onderhawige artikel kori.liks gemotiveer word waarom hul prestasies so uitsonderlik was. metode in ’n studie van dergelike aard word die histories wetenskaplike m etode gebruik met die klem op primere bronne ten einde die verlede so noukeurig en volledig moontlik te rekonstrueer. die primere bronne was onder andere die notules van die suid-afrikaanse olimpiese en rykspeleverenigliig, notules van ver gaderings van die intemasionale olimpiese komitee, amptelike verslae van spanbestuurders en afrigters, amptelike verslae van die organiserende komitees van elke spele, en onderhoude en korrespondensie met deelnemers en ander ooggetuies. nadat die bronne aan interne en eksteme kritiek onderwerp was, is die inligting tot ’n sintese gevoer. resultate en bespreking alhoewel suid-afrikaners (waaronder twee zoeloes) al in 1904 in st. louis aan die olimpiese spele deelge neem het, was die eerste amptelike deelname eers in 1908 toe die spele in londen plaasgevind het. die 19 jarige reggie walker van durban het daar ’n einde aan die amerikaanse oorheersing in die 100 meter gemaak. alhoewel james rector in sy uitdun ’n olimpiese reko rd van 10,8 sek. opgestel het, het walker dit in die semi-finaal en in die linaal geewenaar om sodoende die amerikaner in die linaal die loef af te steek.~ afgesien van die feit dat walker suid-afrika se enig ste olim piese naelloopkam pioen is, is d it van akademiese belang om hier te let op ’n historiese wan voorstelling wat met sy geval gepaard gaan. sedert die amptelike verslag van die londense spele in 1909 gepubliseer het dat walker nie oorsponklik in die suid afrikaanse olimpiese span opgeneem was nie,'! het hierdie fout herhaaldelik in verwante literatuur na vore gekom. dit was eers toe die “verlore” notules van die suid-afrikaanse amateuratletiekvereniging in die laat 1980’s opgespoor is, dat die voile waarheid ontbloot is. dit was in werklikheid ht phillips, ook ’n naelloper, wat eers later in die span opgeneem is nadat pretorianers sy koste betaal het. walker was van meet af aan in die span as sesde keuse.4 in die daaropvolgende spele, in stocldiolm 1912, was dit die marathonatlete se beurt om roem vir suid afrika te verwerf. kenned}7 kane mcarthur en christopher gitsham het nle net eerste en tweede onderskeidelik geeindig nie, maar suid-afrika was ook die laaste land wat so ’n dubbel prestasie in die marathon kon vermag. ’n persoonlike onderhoud met hb keartland,” die olimpiese adetiekafrigter van 1912, het aan die lig gebring dat daar veel meer agter “ kenneth” mearther en “ chris” gitsham se prestasie skuil as wat die reko rdboeke wil laat blyk. so byvoorbeeld was die olimpiese marathon slegs die tweede dergelike nom mer vir gitsham. keartland, wat die potensiaal in gitsham raakgesien het, het hom oppad na swede in londen vir die polytechnic-marathon ingesltryf. gitsham het sy vuurdoop met vlieende vaandels ges laag deur tweede te eindig. hierdie marathon het ook as proewe vir die britse olimpiese adete gedien. keartland was dit ook eens dat gitsham meer talent as die gesoute kenneth mcarthur gehad het. die twee springbokke het die tweede helfte van die wedloop oor 40,200 km saam in die voortou afgele, maar volgens hom het gitsham sy pas ingehou om vir sy spanmaat morele ondersteuning te gee. vyf kilometer vanaf die stadion het gitsham die roete verlaat om by ’n fontein 4 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) water te gaan drink, f ty was onder die indruk dat mcarthur vir horn sou wag, niaar laasgenoemde het iii daardie tyd sowat 200 meter gevorder. krampe het gitsham toe genoodsaak 0111 ’n lang ent te stap voordat hy sy spamnaat agtema kon sit.11 na afloop van die wed loop het die saggeaarde gitsham inderdaad beledig ings na sy spamnaat geslinger omdat liy nie vir liom gewag het nie.7 mcarthur se tyd was 2:36:54," en die van gitsham, 2:37:52,0." na die eerste wereldoorlog is die spclereeks in 1920 in antwerpen hervat. op hierdie spele liet bevil gordon d ’urban rudd die enigste suid-afrikaner geword om ’n volledige stel olhnpiese medaljes te verower. auioewel hy ten tyde van die spele ’n rliodes student aan die universiteit van oxford was, het hy in springbokkleure geliardloop en teen die verwagting in die anierikaners onttroon om die goue medalje in die 400 meter te verower met ’n tyd van 49,6 sek. iiv het in die finaal die uitgetrapte binnebaan geloot, niaar desni eteenstaande sy naaste teenstander met twee meter geklop. in die 800 meter het rudd in die laaste pjivak voorgeloop toe hy gestruikel en sy enkel beseer liet. iiy kon egter daarin slaag om steeds die bronsmedalje in te palm. hy is in die proses deur die britse en anierikaanse kampioene geklop. sy derde medalje was die sihver m die 4x400 meter alios.'1 hi 1928, in amsterdam, het sidney janies montford atkinson die enigste suid -afrikaner geword om die 110 meter liekkietitel te verower.10 wat sy prestasie nog meer indrakwekkend maak is die feit dat hy by die vorige spele, in parys, die sihvemiedaljewemier in die selfde nonuner was. hy het in die finaal ’n 0,25 meter voorsprong geliad toe hy die laaste liekkie raakgesltop en effens gestruikel het. dit. was genoeg vir sy anierikaanse teenstander (daniel kinsey) om hom na die lint te ldop. alhoewel beide ’n tyd van 15,0 sek. aangeteken het, is kinsey eerste geplaas." vier jaar later het sid atlduson die nonimer in 14,8 sek. gewen. met hierdie tyd het hy die ou olhnpiese rekord van 1920 geewenaar.1dit was ook dieselfde tyd wat sy spamnaat, george c weightnian-smith, in die uitdmme behaal het. weightman-smitli, het in die semi-finaal egter ’n nuwe werelden olinipiese rekord van 14,6 sek. opgestel. li die finaal het hy die uitge­ trapte binnebaan geloot, alhoewel dit vir die beamptes mooutlik was om die hekkies so op te stel dat die bin­ nebaan nie gebruik h oef te geword het nie. die uiteiiule van die saak was dat hy vyfde (15,0 sek.) en sid atkinson eerste (14,8 sek.) geenidig het.” ira emery, 49 jaar lank die sekretaris van die snid afrikaanse olnnpiese spelevereniging en bestnurder van verskeie springbokspanne na die spele, het in sy boelt springboks o f die olympiad (1956) geskryf dat dit atkinson -was wat. die binnebaan geloot het en dat liulle op weightman-smith se aandrang bane geruil het. addnson sou toe in die vyfde in plaas van die bnmebaan gehardloop het. geen ander prnnere bron onderstemi emery se verliaal nie en die foto in die amptelike ver slag van die spele toon dat atkinson in die derde baan gehardloop liet.11 snaar viljoen het as ooggetuie ook die verhaal van emery ondten.1" op ’n vraag waaroni hy nie oor die uitgetrapte binnebaan beswaar aangeteken het nie, het weiglitman-smidi verldaar dat hy nooit klagtes op die sportveld sal opper nie,10 suid-afrika se laaste goue medalje in ’n olinipiese atletieknominer (en die enigste deur ’n vrone atleet) is in helsinki in 1952 behaal toe die 28-jarige esdier (nee van heerden) brand die hoogspring vir vrone gewen het. haaiinshiiting in die olinipiese span het met baie kritiek gepaard gegaan, niaar liaar wenlioogte van 1,67 meter was goed genoeg 0111 die wereldrekordhouer met 0,02 meter te ldop.17 die olhnpiese rekord op daardie tydstip was 1,68 meter.1" hierdie prestasie het 1 1 jaar 11a liaar wereldrekord sprong as 17-jarige skooldogter op coetzenburg gekom. i o e , op 29 maart 1941, het sjr ’11 lioogte van 1,65 meter behaal. estlier se rekord is egter nie destyds as ’11 wereldrekord erken nie aangesien die rekordlioogte van 1,67 meter toe agter die naam van dora ratjen van duitsland gestaan het. in 1957 is raljen as ’11 man ont bloot en sy rekord is in 1960 op ’11 vergadermg van die iaaf in rome nietig verldaar. hermann ratjen se ver weer was dat hy in die oorlogsjare deur die nazi’s ged 'ving was 0111 as ’11 won deel te lieem ten einde roeni en eer vir dnitse sport te verwerl. met die sltrappini? vail s57 rekord is esdier s ’11 eers 19 jaar later as wereldrekord erken.lu samevatting ’11 statistiese ondeding van suid-afrika se prestasies op die olinipiese spele van 1908 tot 1960 dui aan dat die atlete 11a die tweede wereldoorlog nie so goed soos voor die oorlog gcvaar liet nie. die enigste goeie na-oorlogse prestasie was in 1952 toe die 13 springbokatlete twee medaljes ingepalm het. i11 1908 het suid-afrika se sewe adete twee medaljes verower, in 1912 het die sewe atlete twee, in 1920 het die 13 atlete drie en in 1924 het die 12 adete twee medaljes gewen. in 1928, 1932 en in i960 is slegs een elk behaal. die atleetgetalle was tien, vier en agt onderskeidelik."" hierdie artikel het slegs op die goue medaljes wat in 1908, 1912, 1920, 1928 en 1952 gewen is, gekonsentieer. i11 1947 het prof ernst jokl gewaarslai dat suid afrika “ bloedinin kails op die ohmpiade” sou h e .21 in sy artikel liet hy daarop gewys dat suid-afrika se adetiekprestasies gestagneer liet terwyl die res van die wereld merlcwaardig verbeler het. hy het dit be klemtoon dat suid-afrika voor die eerste wereldoorlog ’11 werelclkrag in adetiek was, niaar dat die posisie drastics versleg het. hy het vcrskillende atletieklande se bevolkingsgetalle met liul prestasies vergetyk en tot die slolsom gekom dat die skandinawicse lande op daardie tydstip die kern van were]datletick gevorm het. ily het ui daardie vcrband die volgende otmicrkiiil! gemaak: a s hulle (skandinawicse) opperheerskappy ooit be dreicj gaan word, is daar slegs een antropologiese groep wat in die nabye loekoms 11 ernstige mededinger mag word, nl. daardie lede van die swarlvellige afrikaanse (sic) rasse wat kontak met liulle bewerkstellig en hul kennis van meer ervare atleliese lande aanwend. wat gaan suid-afrika met sy naturelle-atlete doen?~ sedert die olinipiese spele van mexiko-stad m 1968 het talle ali'ikalande nieteoriese opgang in die adetielcwereld geinaak.** hi antvvoord op jold se vraag omtrent suid-afrilca se “ naturelle-atlete” , m oct die blaam op die s.a. aniateuratletiekvereniging geplaas word. nog lank voordat die nasionale party ami bewind sports medicine july 1996 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) pevaryl the no. 1 topical antifungal' gckoin lict, het die beheerliggaain iii 1931 bcshiit am die kleiuskeiding toe te pas.'4 hierdie besluit soil vir die daaropvolgende ses dekades ’11 veniictigende effek op siud-acrika se adetiekprestasies lie. adete soos sydney maree, mark plaatjies eii freddie fredericks (om net ’11 paar van die mees oidangse gevalle te noeni) het hul lied in die buiteland gaaii soek. daar kaii slegs gespekideer word hoeveel reggie walkers, kenneth mcarthurs, bcvil rudds, sid atkinsons and esdier brands in die apartlieidsera uooit hid talente ten voile ontwikkel het nie. verwysings 1. van der m enoe fjg. aspiration towards olympism. report o f the first congress o f the olympic a ca d em y o f southern a frica. port elizabeth, 2 6 -2 8 june 1990. (p r e t o r ia ): olympic a ca d em y o f southern africa. 1990: 63-70. 2. van dcr merwe fjg. suid-afrika se deelname aan die olim piese spele. 1908-1960. ongepubliseerde d oktorale proefskrif. p otchefstroom : p u vir c-ho, 1978: 44-45. 3. official report o f the olympic gaines o f 1908. london: the british olympic a ssociation , ( 1 9 0 9 ): 51. 4. lauhscher l. the m yth about reg walker and the 1908 olympic team. sa sport communico 1987; 8 ( 2 ) : 8-9. 5. keartland hb. persoonlike onderhoud. johannesburg. 2 3 april 1976. 6. k eartland hb. p ersoonlik e korrespondensie, 31 maart 1975. 7. keartland hb. persoonlike onderhoud. johannesburg, 2 3 a pril 1976. 8. kainper e. encyclopcdia o f the olympic games. dortmund: harenberg, 1972: 8. 9. van der merwe fjg. suid-afrika se deelnam e aan tlie olim piese spele. 1908-1960. ongepubliseerde d oktorale proefskrif. p otchefstroom : p u vir cho, 1978: 143. 145-146. 155. 10. k ainper e. lexikon der 12000 olympioniken w h o’s who al the olympics. graz: i^eykain-verlag. 1975:10. 11 .z u r meyecle e. d ie g esch iclite der olyinpischen leichtathletik, band 1. munchen: b artels & wernitz, 1968: 165. 12. k am per e. encyclopedia o f the olympic games. dortmund: harenberg, 1972: 9. 13. van der merwe fjg. suid-afrika se deelnam e aan die olimpiese spele. 1908-1960. ongepubliseerde d oktorale proefskrif. potchefstroom : pu vir cho, 1978: 250-253. 14. official report o f the ninth olympiad, am sterdam 1928. am sterdam : netherlands olympic committee. 1928: 436. 15. viljoen ,jh. persoonlike onderhoud, pretoria. 10 september 1975. 16. zur megede e. d ie g eschichte der olympischen leich­ tathletik, band 1. miichen: bartels & wernitz. 1968: 198 199. 17. van der m enoe fjg. suid-afrika se deelname aan die olimpiese sjiele. 1908-1960. ongepubliseerde d oktorale proefskrif. p otchefstroom : p u vir cho, 1978: 435. 18. k am per e. encyclopedia o f the olympic games. dortmund: harenberg, 1972: 35. 19. quercetani r j a t h l e t i c s a history o f modern track and field athletics, 1860-1990, men and women. london: iaaj', 1990: 255; joubert a . persoonlike korrespondensie, 1984. 20. van der merwe fjg. suid-afrika se deelnam e aan die olim piese spele, 1908-1960. ongepubliseerde d oktorale proefskrif. p otchefstroom : p u vir cho. 1978: 629. 21. jokl e. oils a tlete het bloedmin kans op die olimpiade. fleur 1947; 2 ( 4 ) : 41-43. 22. jokl e. otis a tlete het bloedmin kans op die olimpiade. fleur 1947; 2 ( 4 ) : 42. 23. van der merwe fjg. sportgeskiedenis: ‘n handleiding vir suid-afrikaanse studente. stellenbosch: fjg publikasies, 1994: 182-186. 24. a nderson pg. a n investigation into the effect o f race and politics on the developm ent o f south african sport (19 70 1 9 79 ). ongepubliseerde d oktora le proefskrif. stellenbosch: universiteit van stellenbosch, 1979: 36. q 6 if you wish to see more, call your roche syntex division representative at (011) 974-5335 universal application trneo corporis n— _ l i,, _ rropnytoaic treatment tmeo corporis tinea pedis dandruff seborrhoeic dermatitis tinea capitis otitis externa tineo barfeoe t in e a versicolor r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the limits to human performance: a physiological perspective ja hawley & e j schabort ■■running records are still far below human physiological limits. the i eslrainls on performance are psychological: good runners do not work as hard once they have set a record or won a medal." ry(lcr c , ai (1()7g) h is t o r ic a l b a c k g r o u n d although tlic purest csseucc o f the sporl o f miming is the competition and stmgglc o f one atldelc against another, there has always been sometliing magical about the setting of' a world record, and its constant challenge bums idee an eternal flame for those individ­ uals capable o f such goals. those athletes who have bioken a world record belong to a “ super elite” group, for the stretching ofluunan capability, the breaking of barriers, and the conquest o f unknown territory arc pos­ itive qualities which define mankind as a whole. li ath­ letics, world records also help to give reason and incen­ tive to those outstanding efforts o f a few athletes and ensure that the great names o f the past, as well as those o f the present and the future are never forgot­ ten.sl but just how fast can men and women nm ? wliat are the physiological limits to human performance? will women ever nm as last as men over any distance? these and other questions have recently been the focus o f considerable scientific debate. li the past, most theories 011 these issues were large­ ly inelegant because they were seldom based upon any scientific rationale and logic but, rather, instinctive pre­ dictions centred upon personal belief's o f die time.1'"'* latel}-, however, results from competitive running events have provided valuable insight for sports seicn tists into several key integrative areas o f exercise phys­ iology: world records offer a framework for die discus­ sion of how various physiological factors interact as determinants o f perfonnaiice.10'-,--'7',l:’"-4s considerable effort is now focused 011 die study o f adiletic perfor­ m a n c e . i n d e e d , diuing die past decades many attempts have been made at providing a mathematical description ofluunan performances based 011 the char­ acteristics of the metabolic processes that provide e lcm ica l energy to power muscle contrac tion.“' 1, -,,.-,':,?'’m« « a ’ these models (to be discussed sub­ sequently) often provide very accurate predictions o f estimated and actual athletic performance. undeistandably, however, both coaches and athletes are highly suspicious o f sports scientists’1’ who claim from dicir theoretical mathematical models that “ a correspondence: dr john a hawley, f.a.c.s.m. mrc/uct bioenergetics o f exercise research unit sports science institute o f south africa p o box 115, newlands 7725 phonc:(0 2 1 ) 686-7330 fax:(0 2 l ) 686-7530 muwinun or no training is required for approximately it) clays before a competition to avoid a negative effect of tramuig (fatigue) 011 competition perform;uicc!” i he purpose o f (his article is to investigale (he evo­ lution o f human performance and, within a physiologi­ cal uamcwork, examine the ‘ limits' to future athlciic lecouls. obviously, a comprehensive disenssion o f all 1 mining eveuls over a wide range o f distances is bcvond (he scope of tliis article. for this purpose, (he men’s and womens record for the one mile ( 1 , 6 0 0 . 3 6 m) has en chosen to focus 011 dicse and other questions. the progress of human performance at the turn o f the cent my a famous coach o f (he lim e1 stated o f die men’s world mile mark: . . the man who has made this record is ll.’ g. george. his time . . . four minutes 12 seconds, and the probability is that this record will never be broken". almost one hundred vcars later, die record for the men’s 011c mile is some 3 0 see ( o r approximately 2 1 5 1 1 1 ) faster (table 1 ). however die current women’s record holder, paula ivan o f rumania woidd still be soundly beaten by walter george. 11 should be noted for posterity that william cummimjs, the sole competitor numing against george, collapsed’ 7 0 yards hom the finish o f the race from ‘exhaustion'.51 lablc 1 : the evolution oj the men s one mile ( i.(>()<) metre) world record since the first sub-four minute mile in 1954 atlilelc nationality roger g. bannister jolui m. lnndy derek ibbotson herbert j. elliot peter g. snell peter g. snell michael jazv ja m es r rynn jam es r. rynn filbert bayi jolm g. walker sebastian n. coe si even m. ovett sebastian n. coe steven m. ovett sebastiini n. coe stephen cram n oin cddiiic m orccli great britain australia great britain australia new zealand new zealand france u.s.a. u.s.a. tanzania new zealand great britain great. britain great britain g reat britain great britain great britain algeria perfbnuiuice dale o f ( in in :see) record i 3:5 9.4 00 -05-1954 3 :5 8 .0 21 -00-1954 i 3:57.2 19-07-1957 3:5 4.5 00 -08-1958 3:5 4.4 2 7 -0 1 -1<)02 3:54.1 17-11.1904 3:53. 0 09-00-1905 3:5 1 .3 17-07-1900 3:51.1 23-00-1907 3:5 1 .0 17-05-1975 3:4 9.4 12-08-1975 3:4 9 .0 17-07-1979 3:4 8 .8 01-07-1980 3:4 8.53 19-08-1981 3 :4 8 .4 0 20-08 1981 3 :4 7 .3 3 28-08-1981 3:4 6.32 27 -07-1985 3:4 4 .3 9 12-09-1993 why then is (lie men’s world mark for one mile still so far ahead o f the women’s? can (lie differences in improvements seen in the men’s and women’s record over die past forty years be explained on a physiological basis? “ ^ sports medicine .july 1996 / r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) firstly, when considering the progress o f lnunan per­ formance, it should be noted that men have participat­ ed in organised competitions over a wide range o f stan­ dard distances for more than 100 y e a r s . it is oidy dur­ ing the past 20-30 years that similar opportiuiities have been afforded to women. indeed, the international amateur athlctic federation (iaaf) did not sanction races for women that were longer than 1,000 in until 1967 when the 1,500 in and the mile were “ officially” recognised. the .10,000 m for women was not added until as recently as 1981. it is somewhat miclcar when the iaaf began to aclaiowledgc the women’s marathon (42.195 ltm), but this event was not contested in olympic competition until the los angeles games in 1984. secondly, an analysis o f recent, race times for women show that their world records and best performances arc not as consistent as those for men, particularly over the longer distances.1" of course, one might reasonably argue that this is as a residt o f the shorter liistory of women’s middle and long distance running and die cor­ responding lack o f competitive opportunities. thirdly, it is only during the past two decades that several coimtries, most notably china and some o f the african nations, have acknowledged and belatedly encouraged women’s participation in liigh level sport. tims, when “ pre-iaaf” times are considered, the time span available to critically and objectively analyse women’s performances should probably be limited to the last quartcr-ccntiuy because o f insufficient opportu­ nities for women to compete at almost every level males have. given this position of historical disadvantage, it is perhaps not siuprising to find that since 1954 die rate of improvement o f the women’s world mile record is more tiian double that o f the men’s mark (14.7% ver­ sus g.3%, respectively). finally, a closer examination o f tables 1 and 2 reveal that, o f the 18 men’s mile world records since 1954 (acliieved by 13 numcrs), and the 17 women’s best pertablc 2: the evolution o f the women's one mile (1,609 metre) world record since the first sub-five minute mile in 1954 athlete nationality perform ance (in in :scc) date o f record diane leather g reat britain 4:59.6 29-05-1954 diane leather cheat britain 4 :5 0 .8 24 -05-1955 diane leather g reat britain 4 :4 5 .0 21 -09-1955 marisc ciianilx-tluiii new zealand 4:4 1.4 os-12-1962 aimc smith g reat britain 4:39.2 13-05-1967 aimc sm ith g rea t britain 4:37.0 03-06-1967 maria g onnners holland 4:3 6.8 14-06-1969 ellen tittel east germ any 4:3 5.3 20-08-1971 paola cacchi-pigni italy 4:29.5 08 -08-1973 natalia maraseseu rom ania 4:2 3.8 21-05-1977 natalia maraseseu rom ania 4:22.1 27 -01-1979 mary d cck cr u.s.a. 4:21.7 26 -01-1980 lyudmila vcscllcova u .s .s .r 4:2 0 .8 9 12-09-1981 mary d ccker-tabb u.s.a. 4:1 8.08 09 -07-1982 m aricica puica rom ania 4:1 7.44 16-09-1982 mary s lan cy-d cck cr u.s.a. 4:16.71 21-08-1985 paula ivan rom ania 4:15.61 10-07-1989 fonnances (set by just 1 1 numcrs), onlv two records have been attained by african runners. considering the current athletic dominance o f the african nations, niosi notably kenya, ethiopia, and morocco over a wide range o f distances (3,000 m to the marathon) and events (road races, track, and cross country), this is somewhat surprising. with this vastly different background, and with reference to the evolution o f the world record for the mile for the past forty years (tables 1 and 2), one issue warrants further discussion. although it was not until may 6, 1954, that roger bannister became the first man to ran under lour min­ utes for the mile (3:59.4), it was probably one year ear­ lier in .june 1953 id'ter running 4:02 for an invitation mile race at a schoolboys athletic meeting, that bannister and his coach, franz stampll, realised he was capable o f miming a ‘ sub four’ . in contrast, john landy from australia, who by april 1954 had already run the mile in tuidcr 4:03 on no fewer than six differ­ ent occasions, stated “...the four minute harrier is a brick wall. 1 shall not attempt it again.” yet, only 1 \vo weeks after baimistcr had secured fame for life as a result of his famous run at oxford, landy ran 3:58 for the mile and became the new world record holder. as bannister later summarised "... though physiology may indicate respiratory and cardiovascular limits to muscular effort, psychological and other factors beyond the ken o f physi­ ology set the razor's edge o f defeat or victory and deter­ mine how closely the athlete approaches the. absolute lim­ its o f performance".' in this vein, and with reference to the women’s record, it was perhaps much more than pure coincidence that diane leather o f great britain became the first female to break five minutes for the mile just three weeks after bannister set his historic mark. this and other similar feats have led certain researchers to conclude that "... the barrier to be overcome by the runner who wants to he a champion is psychological. the last record set and the ivillingness o f athletes to try to break it are the deter­ mining factors for the next record. "w the inference is that a highly competitive situation brings out in the finest o f atldetes a level o f performance of which even they are incapable under less challenging circum ­ stances. the magnitude o f this effect, which is almost impossible to quantify, appears to have been ignored by many researchers who have employed “ mathematical equations” to predict future performance. can im pr o v e m e n ts in p h y s io l o g y e x pla in t h e im p r o v e m e n t in p e r f o r m a n c e ? there are a number o f key physiological factors related to successful middle-distancc and distance running per­ formance. these include: (i) a high (>70 m l/kg/m in) maximal aerobic power (vo;w); (ii) the ability to utilise a high percentage o f vo--..* for sustained periods; (iii) the ability to sustain high (>20 km /hr) running speeds and resist muscular fatigue; (iv) a fast naming speed at the “ lactate tlueshold” ; (v) an efficient/economical nuuiing tccluiique, and (vi) a high anaerobic (oxygen independent) capacity. these determinants o f superior performance have been extensively reviewed else• wherc.“h'" lt'~l4" the current issue is whether improve­ ments in any one (or more) o f these factors can explain the large improvements in human performance over the past centiuy 8 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) • for muscular pain • effective pain relief • site specific • non-staining • n on-greasy reparil-gel relieves m uscular pain. i macmusj madaus pharmaceuticals (pty) ltd reg. n o , 77/00174/07 2nd road‘ ( c n r w road), randjespark, midrand 1685 reparir-g el 100 g contains: aescin 1,0 g; diethylamine salicylate 5,0 g. reg. no. g/13.9/2367 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) with regard to a numer’s maximal aerobic power, sid robinson and colleagues working at tlie harvard fatigue laboratory, reported very high vo.,.« values in elite runners over fifty years ago.4' a voa,,.,,* value o f 82 m l/kg/m in was measured for donald lash, one o f tlie first runners to run two niiles in less than nine minutes. these investigators also reported several other numcrs with vo,,,,,* values higher than 75 m l/k g /m in .^ a s tlie highest vo,,,,* ever reported for a runner recorded in the m o d e m era in a reputable laboratory is 85 m l/kg/m in for dave bedford, ex-world record holder for 10,000 m ,5 it seems unlikely that increases in maxi­ mal aerobic power are responsible for the large improvements in tlie world records for varying athletic events. instead, it may b e that the gradual improvements in performance by elite runners are more related to their improved ability to sustain a higher fraction o f vo„,« in competition, and also to better running economy and technique.44 this view is consistent with tlie evolution o f training practices this past century. for example, from tlie early 1900’s to the late 1960’s, there was a steady increase in tlie frequency, intensity and duration o f training so that by tlie early 1970 s most track run­ ners were undertaking several hours o f training a day on a week to week basis. since that time, tlie training regimens o f top numers has not changed dramatical| y :*5 .4 0 .4 7 finally, an analysis o f world records at distances from one mile to the marathon reveal that it is mainly an increase in specific endurance (i.e. tlie ability to resist fatigue) rather than any enhancement in basic speed or “ anaerobic” power that is responsible for tlie gradual improvements in many events over tlie past fifty' years.41 tlie dominant effect of tliis improvement in spe­ cific endurance or fatigue resistance (i.e. the ability to maintain a given speed) is hidden by tlie tradition to time races at a constant distance, rather than to mea­ sure the distance a runner coidd cover in a specific time. to illustrate tliis point, in 1969 derek cku'ton of australia ran a marathon in 2 lir 08:32, at an average velocity o f -3 2 8 m /min. tliis was slightly faster than tlie mean running speed for tlie men’s one mile record some hundred years previously set by britain’s cadet marshall in 1852 at -3 2 6 m /m in .53-51 in other words, clayton demonstrated a specific endurance more than 26.2 times greater than marshall. in physiological terms, at tlie same speed, clayton was able to run 26 times further than marshall! perhaps more important­ ly, clayton possessed a relatively m odest vo,..,* o f only 69.7 m l/k g /m in ,11 illustrating that it is a runner’s max­ imal speed and economy o f motion at race pace, rather than her/his vos,„«« which predicts athletic performaiice.114*’ , . , apart from tlie physiological improvements associat­ ed with superior performance, there are, o f course, other factors which majr explain why world records have continued to fall. the introduction o f synthetic running tracks can improve competitive performance by 2 -3% compared to older traditional surfaces like grass and cinders.-"'’1’ professionalism, commercialism, mid more numerous competitive opportunities today com ­ pared with forty years ago mean that more potential record setters have tlie chance to train and compete on an almost full-time basis. it is also possible that the use o f banned substances may have contributed to the improved perform ances o f some athletes. however, whether the m odem athlete’s nutritional practices have contributed to their improved (raining capacity and race performances is somewhat doubtful.*" mathematical modelling of human running performance as noted previously, there have been many attempts bv sports scientists to “ m odel” or describe atliletie peiloi mance based on a complex interaction of many input variables such as tlie upper limits o f several metabolic processes involved in power production, and die input, dose-effect o f training interventions. many more (ac­ tors, however, remain to be specified and precisely quantified.™ nevertheless, several investigators have presented models that describe, with a high degree of accuracy, running performances over various distances. for example, ward-smith45 proposed a model for mate performances where the average absolute error between estimated and actual rumiing times for all dis­ tances from 100 m to 10,000 m was only 0 .86%. although at first sight tliis model appears very accu­ rate, it was criticised by other workers in the field because it failed to take into account tlie well docu­ mented progressive decline in die aerobic power output that can be sustained as the distance run increases, to r example, even a world-class runner is only capable of sustaining h er/liis vo', -, for —420 sec.1** * ih cica ltci, the fraction o f voa,.,.,* that can b e sustained during a race decreases linearly from 100% at time t, to 85-90% for a 60 min race, 80-85% for a 120 min race, 75-80% for a 180 min race and so on.37:18 taking this factor into account, peromiet. and thibault" suggested a modifica­ tion o f ward-smith’s4" hyperbolic model which reduced the absolute error between actual and estimated run­ ning times for races from 60 m to tlie marathon foi. both men and women to only 0.73%. tlie complete m odel of running performances proposed by these and other workers not oidy provides a quantitative description of endurance capability, but also an estimation o f (lie rel­ ative contributions o f the various oxygen dependent and oxygen independent power systems to the total work output according to the duration o f the race."1 the theoretical considerations o f such m odels are complex and outside tlie brief o f tlie current paper. the limits to human performance: where to from here? perhaps o f greater interest and relevance to athletes and sports scientists alike are the projected improve­ ments in rumiing times for various distances based on tlie various mathematical models. table 3 lists the pro­ jection o f both tlie men’s and women’s world record for table 3: projection o f the m en’s and women’s world mile records year 2000 2088 2040 ultimate performance men 3:41.96 3:33.29 3:29.84 3:18.87 women 4:10.79 4:00.83 3:59.82 3:43.24 data arc from pcroimct and thibault, 1989 10 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) tlie mile, along with tlie ‘ultimate performance’ for that distance.^ as can be seen, a 3:30 mile is projected for men by die year 2040, even though in 1954 roger bannister forecast tliat tliis mark would liave been accomplished by 1990/' in order to attain such a level o f performance, the miler o f tlie future will need a vo,... o f ~91 m l/kg/m in while also possessing suffi­ cient basic speed to run die quarter mile in around 44 sec and tlie 800 m in around 1:42. although such a range o f performances by the same runner seem some­ what unrealistic at first sight, tlie current world records for tlie 400 in and 800 m already surpass these ‘hypo­ thetical’ marks (43.29 sec for 400 111 by harry ‘butc.li’ reynolds; 1:41.73 for 800 ni by sebastian coe). indeed, as discussed previously, it is likely tliat future improve­ ments in world records wall com e not from any increase in instantaneous speed or power derived from tlie oxy­ gen-independent “ anaerobic” pathways, but rather an increase in fatigue resistance or specific endurance. tliis being tlie case, then one might reasonably argue tliat tlie current m en’s world mile mark.(table 4) is already well overdue for revision. there are presently many runners with sufficient basic speed over botli 400 ni and 800 m who, with tlie development o f sufficient specific endurance, should b e capable o f significantly reducing tlie present record. indeed, according to data derived from performance tables comparing tlie various running distances from 800 m to the marathon,1:1 tlie men’s world mile record ought to be mound 3:42 hi order to be comparable with the present 5,000 m (12:44.39 and 10,000 m (26:43.53) world best times, both held by ethiopia’s haile gebresilassie. table 4: the fastest mile: a breakdown o f noureddine morceli's world record distance (m) 400 800 1,300 1,600 lap times (sec) 54.9 57.7 57.3 54.5 total time (miii:sec) 0:54.9 1:52.6 2:49.9 3:44.39 set at reiti, italy, oil 12 september 1993 @ 1838 lir. ambient ttanpciatmc 20 c, relative luunidity 50%. data are from ziir megedc and hymans, 1995. finally, it has recently been proposed tliat for certain running distances, tlie performance o f women may equal those o f men within tlie next few decades.w although tliis seems extremely unlikely, the results from a recent study from tliis laboratory2 do suggest tliat for ultra-marathon events at least, women ma}’ be closing tlie gap. bam et al.,found that when male and female rtumers were matched for age, training his ton' and race tune over 56 km, tlie women outperformed the males over the ultra-marathon distance o f 90 ion. hi fact, tlie crossover” point at which the women become faster than their male counterparts was after ~ 66 km. tliis was in spite o f tlie males being much faster over all distances from 5 ion to 42 km. it was hypothesised tliat women ultra-marathon runners may have greater fatigue resistance than do cquallv-trained m e n ; although tlie precise mechanisms for this greater spe­ cific endurance is not clear," it may simply b e related to tlie smaller sizes and lighter body mass o f the females. figure 1 : the progression o f the men’s (fdled circles) and women’s (open circles) world record for one mile (1,609 m ) since 1954. the extrapolation o f the lines o f best fit for the data sets would estimate that by the sydney olympic games, to be held in the year 2000, the men s record will be 3:42 and the women’s around 4:00. year conclusion in conclusion, it seems likely tliat any future improve­ ments in tlie current world records for distances from one mile to tlie marathon mall be achieved by those ath­ letes able to sustain high rumiing speeds and resist the onset o f muscular fatigue, rather than any significant increase in absolute rmming velocity per se. for this to happen, the runners must be in a highly competitive situation which will bring out tlie highest level o f per­ formance: tlie magnitude o f this psychological effect seems to have been somewhat overlooked by those sports scientists who have employed mathematical models to describe and predict future race perfor­ mances. while it seems unlikely tliat women will ever beat men over any distance until such time that the}' caii run shorter trade distances as fast as tlie males, one might speculate tliat women’s performances may one day equal those of the leading men in verv long (i.e.> 421on) distance races. references 1. andrew s h. training for a th letics and general health. a rthur pearson pub. london. 1903. s. bam j, n oakes td, juritz j. dennis sc. could women out­ run men in ultra-maralhon ra ces? medicine and science in sports and e xercise (in review). 3. bannister rg. the first four minutes. putman. london 1955. sports medicine july 1996 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 4. b annister rg. muscular effort. british medical bulletin, 1956; 12: 222-225. 5. bergh u. p hysiology o f cross-country ski racing. human k inetics, champaign, illinois, 1982. 6. brandon u . physiological fa ctors associated with middle distance running performance. sports medicine, 1995; 19: 268-277. „ , 7. brandon u , b oileau r a . the contribution o f selected vari­ ables to middle and long distance run performance. journal o f sports m e d i c i n e and physical fitness, 1987; 2 7 :1 5 7 -1 6 4 . 8. brandon lj, b oileau r a . influence o f metabolic, mechani­ cal and physique variables on middle distance running. journal o f sports medicine and physical fitness, 1992; 32: 1-9. 9. c oetzer p, n oakes td, sanders b, lam bert mi, b osch an, wiggins t, d ennis sc. superior fatigue resistance o f elite black south a frican distance runners. journal o f applied physiology, 1993;75:1822-1827. 10. costill d l inside running: b a sics o f sports physiology. carmel, in: b enchm ark press, 1986: pp. 1-189. 11. costill dl, branam g, e ddy d, sparks k . determ inants o f marathon running success. internationale zeitschrift fu r a ngew an dte p hysiologies. 1971; 2 9 : 249-254. 12. costill dl. f o x el. energetics o f marathon mnning. medicine and science in sports, 1969; 1: 81-88. 13. d aniels j, gilbert jr o xygen power... : perform ance tables fo r d istan ce runners. tempe. arizona, 1979. 14. ekblom b, berglund b. e ffect o f erythropoietin administra­ tion on maximal aerobic power. scandinavian journal o f medicine and science in sports, 1991;1:88-93. 15. ekblom b, goldberg a n , gullbring b. r esponse o f exercise after blood lo ss and reinfusion. journal o f a p p lied physiology. 1 9 7 2 :3 3 : 175-180. 16. e ttem a jh. limits o f human perform ance and energy production. in tern a tion a le zeitschrift fu r a n gew a n d te physiologie, 1966; 22: 45-54. 17. h andelm an gh, smith dc. comparison o f running and swimming records. sportwissenschaft, 1980, 2. 161-168. 18. h a w ley j a . s ta te o f the art training guidelines fo r endurance perform ance. south a frican journal o f sports medicine, 1995; 2: 7-12. 19. h aw ley j a , h opkins w g. a ero b ic glycolytic and aerobic lipolytic p ow er system s. a new paradigm with implications fo r endurance and ultra-endurance events. sports medicine, 1995; 19: 240-250. 20. h a w ley j a , d en n is sc, lindsay fh, n oa k es td. nutritional practices o f athletes: a r e they sub-optim al? journal o f sports sciences, 1995: 13: s75-s78. 21. h aw ley j a , my burgh k h , n oakes td, d ennis sc. training techniques to improve fa tigu e resistance and enhance endurance p erform an ce. journal o f sports s cience ( supplement) , in press, 1996. 22. joyner mj. modelling: optimal marathon perform ance on the basis o f physiological factors. journal o f a pplied physiology, 1991; 70: 683-687. 23. joyner mj. physiological limiting f actors and d istance running: in fluence o f g ender and a g e on r eco id perform ances. in : h olloszy j o (e d ito r), e xercise and sports science reviews, 1993; 2 1 ; 103-133. 24. k eller b. a theory o f com petitive running. physician today. 1973; 26: 43-47. 25. leger d, mercier d, gauvin l. the relationship between : % vo-.... and running perform ance time. in: landers dm (e d itor). sport and elite performers, volume 3. human k in eties publishers, champaign, illinois, 1986; pp. 1131.20 26. lloyd b b . the energetics o f running: an analysis o f world records. a dva n ces in science, 1966; 2 2 : 515-530. 27. lloyd bb. w o r l d r u n n i n g records as maximal performances. o xygen d eb t and o th er lim iting fa cto rs. circulation research, 1976; x x , x x i : 218-226. 28. londeree br. the use o f laboratory test results with long distance runners. sports medicine, 1986: 3: 201-213. 29. mcmahon ta, greene pr. fast runniny tracks. scientific am erican, 1978; 239: 148-163. 30. mcmahon ta, greene pr. the influence o f track compliance on running. journal o f biom echanics, 1979: 12: 893-904. 31. mognoni p lafortuna c, r usso g, m inetti a . a n analysis o f world records in three types o f locomotion. european journal o f a pplied physiology, 1982; 49: 287-299. 32. morton kh. the suprem e runner: ivhat evidence now'? australian journal o f sports science, 1985; 3: 7-10. 33. morton rh . fitz-clarke jr, b anister ew. modelling human perform ance in runniny. journal o f a pplied physiology. 1 9 9 0 :6 9 :1 1 7 1 -1 1 7 7 . 34. n oakes td. im plications o f exercise testin g jo r prediction o) athletic performance. medicine and science in sports and exercise, 1988; 2 0 : 319-330. 35. noakes td. lore o f running. oxford university press. cape town, 1992, pp. 266-270. 36. noakes td, myburgh k ii. schall r. peak treadmill running velocity during the v o a™ test predicts running perfor­ mance. journal o f sports science. 1990: 8: 33-45. 37. peronnet f, thibault g. a n a lyse physiologique de la perfor­ mance en course a pied: revision du modele hyperboliquc. journal o f physiologie ( paris). 1987: 82: 52-60. 38. p eronnet f. thibault g. m athem atical analysis o f running performance and world running records. journal o f applied physiology, 1989; 67: 453-465, 39. r o b ertson r j , gilcher r, metz kf. hem oglobin concentra­ tion and aerobic work capacity in women follow ing induced erthyrocythem ia. journal o f a pplied physiology. 1984; 57: 568-575. 40. robinson s, dill db, r obinson rd, t zankoff sp. wagner ja. physiological ageing o f cham pion runners. journal o f applied physiology, 1976; 41: 46-51. 41. robinson s, edwards ht, dill d b . new records in human power. science, 1937; 85: 409-410. 42. rumball wm, coleman ce. a nalysis o f runniny and the prediction o f ultimate performance. nature, 1970; 228: 184 185. 43. r yder hw, carr hj, h erget p. future perform ance in footracing. scientific a m erican, 1976: 234: 109-119. 44. saltin b, a strand p-o. maximal oxygen uptake in athletes. journal o f a pplied physioloyy. 1967; 23: 353-358. 45. ward-smith aj. a m athem atical theory o f running, based on the first law o f thermodynam ics and its application to the perform an ce o f world-class a th letes. journal of biom echanics, 1985; 18: 337-349. 46. wells cl, p a te pr. traininy fo r performance o f prolonged exercise. in: lamb dr, murray r (e d ito rs ). perspectives in exercise science and sports medicine volume 1. prolonged exercise, benchm ark press. indianapolis, 1988: 357-391. 47. wilt f. h ow they train. volume ii. long d istance (second e d ition). track and field news, los a ltos. california. 1973; pp. 1-126. 48. whipp bj, ward sa. will women soon outrun m en? nature, 1992; 355: 25. 49. williams mil wesseldine s, somma t, schuster r. the effect o f induced erythrocythem ia upon 5-mile treadmill run time. medicine and science in sports and exercise. 1981. 1 3 :1 6 9 -1 7 5 . 50. wilkie dr. equations describing pow er input by humans as a function o f duration o f exercise. in: cerretelli p. whipp bj. (e d itors), e xercise b ioenergetics and gas exchange. new york: elsevier, north holland, 1980: 75-80. 51. zur megede e, h ym ans r. progression o f world b est perform ances and official i a a f world r ecoid s. international a m a teu r a th letic federation. multiprint. monaco, 1995. __□ 12 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychological preparation for olympic athletes dr ii schomer dept o f psychology, u.c.t introduction after winning 7 gold medals at tlie montreal olympics mark spitz said: “at tliis level o f physical skill, tlie dif­ ference between winning and losing is 99% psychologi­ cal” .' h ie reason is tliat elite athletes in a specific sporting discipline are, to a large extent, fairly equal 011 phj'siological, technical and tactical factors. when elite athletes compete tlie one who wins is usually tlie one who is mentally the strongest 011 that given day. where­ as physical abilities are seen as relatively stable, psy­ chological factors primarily determine the daily varia­ tions in performance-.rtisliall goes as far as advocating sport psychology as “ the key to sporting excellence tuid success” ’. current thinking and practice in applied sport psy­ chology assumes tliat the athletes’ level o f performance is a direct: consequence o f the way athletes are thinking and feeling.1 sport scientists and athletes acknowledge that a negative psychological set, such as feelings of frustration, fear, anger and worry, negative thoughts and imagery, and task-irrelevant thoughts typically impairs performance. sport competitions are stressfiil events. athletes who overreact to the challenge experience anx­ iety mid tension which can adversely affect physiologi­ cal and cognitive processes to sncli an extent tliat they perfonn below their potential mid expectations. the athlete displaying a palpitating heart, a dry mouth, tight or shaky muscles, rapid breathing, a tight stom­ ach, poor concentration and unfocused negative thoughts cannot hope to perfonn optimally.’ 5 “ what is needed is a positive psychological set that, mobilizes the physiological reactions essential for peak performance. tlie likelihood o f achieving peak perfor­ mance increases dramatically as athletes consistent^ generate tlie mental climate that lias been identified by numerous studies1-™ to optimize output: athletes do their best when relaxed and alert: tlie psychological ideal performance state is difficult to sustain during high-powered competition and years o f tedious train­ ing.” to become an olympic athlete it has to be experi­ enced consistently and once at the olympic games it has to be right there. characteristics of success although no set distinguishable “ athletic personality”7 has been identified in tlie sport psychological litera­ ture, a certain psychological profile emerges again and again when sport scientists examine succcssfiil elite athletes, regardless o f the source o f the data or the nature o f tlie sport.1 successful elite athletes display the following characteristics mid psychological slrills: 1) consistent self-regulations o f arousal (feeling energized yet relaxed) 2) superior concentration (being appropriately focused) 3) high sell-confidence (positive attitude) mid 4) determination, commitment and control (clear sense o f direction, meaningfuhiess and aware­ ness). allowing for individual variations, (lie above-mentioned psychological commonalities are necessary predisposi­ tions foi the psychological ideal performance state to be propagated mid maintained. the ideal performance state does not just; happen. the mental skills needed to achieve and maintain the ideal performance state are learned through knowledge and practice just as the physical skills and strategies o f the sport are learned and practised. the best preparation or countdown to competition rituals involves behavioural sequences that get die athlete physically mid mentally ready for com ­ petition. tlie physical preparations and training has to go hand in hand with tlie inclusion o f psychological principles and procedures if athletes are to maximise their chances o f being ready to peak at competition time.”-1" h ie ultimate goal oi psychological skills training is for each athlete to learn how to create consistently at com petition time the ideal perform ance state (thoughts, feelings, bodily responses) typically associat­ ed with his or her peak performance.'” 1'1 psychological skills training programmes emi help athletes’ plan effec­ tive behavioural protocols or preparation rituals that emi be used regularly as pre-competition mid competi­ tion readying procedures. psychological skills training out­ line compieliensive psychological skills training pro­ grammes typically follow a set structure with three dis­ tinct phases.s 1. education phase: this phase involves explaining to atlilefes the importance o f developing mid learning psychological skills mid how these skills affect per­ formance. 2. acquisition phase: ihis phase focuses 011 strategies mid teclmiques to learn the different psychological skills. rather than imposing a standard package on the athlete, it is important to develop specific psy­ chological strategies tailored to the athlete’s uuique needs, ability and strengths as well as tlie specific demands o f the sport.511 3. piactice phase: tliis phase lias tliree main objec­ tives: to automate skills through overlearning, to instruct athletes to consistently integrate psycholog­ ical slcills into their performance situations, and to simulate skills that tlie athlete will draw 011 during tlie actual competition. & the most counter-productive time to implement a psy­ chological skills training programme is after the start o f tlie competitive season mid there is concern because athletes are performing below their potential. at this time psychological skills training amounts to a quick-fix solution and is rarely effective. it can also be detrimen­ tal to malic athletes aware oi psychological aspects of competition that should be addressed'when there is insufficient time to learn the new psychological skills needed for control. f lic most productive time to implement a psychologsports medicine july 1996 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ical skills training programme is during the off-season or pre-season (long before the competitions begin) when athletes are well-rested and are in a relatively pressurc tree situation, and there is sufficient time to leam new skills.1:1 mere exposure and one-off practice o f psychological skills training techniques by 110 means prepare athletes for successful implementation o f these skills in olympic competition. rather, they must becom e automatic and second-nature to b e effective. gould, eldtuid and jackson14 reported that 1988 u.s. olympic wrestlers who had won medals had internalized their mental strategies to the-extent that, they reacted automatically to adversity, whereas 110 11-medalists did not have their coping strategies as internalised and had to make a con­ scious effort, to use them wlieu faced with mishaps. they even suggested that the specific coping strategy used may not b e as important as the elite athlete’s abil­ ity to produce that strategy iu an automized mode. for ps3rchological skills and coping strategies to becom e automatic and second nature, requires the long-term practice o f such skills that need to be integrated with physical skills training.5'811’ it can take athletes several months to a year to master the new psychological skills and successfully apply them in actual competition. orliclc1" reported that tliis process usually takes the highly committed athletes about three years o f regular practice before things really come together mentally for them. leading up to the olympics with respect to providing hie most effective service dur­ ing die final months leading up to the olympics, it is imperative not to make major changes to die athletes’ routines and it is not the time to introduce new psycho­ logical, physiological or technical concepts. by tiiis time athletes and coaches should have their plans together. typically, die closer one gets to the olympics them­ selves, die aim should be to refine and fine-tune the skills diat have already been practised. a11 appropriate approach focuses 011 suggestions how athletes might handle part icular concerns such as readiness, plans for distractions, preparation du-ougli simulation, familiari­ sation widi d ie olympic site, lack o f personal space, dealing with media, dealing with interpersonal/person­ al conflicts, developing a plan for being and feeling in control in the olympic environment, ensuring tiiat ath­ letes and coaches have an effective pre-event plan, espe­ cially just prior to die start o f die event, how to control pre-event anxiety, guarding against overtraining, and emphasizing d ie need for adequate rest when faced with high levels o f stress. 11",1<> psychological sldlls training guidelines tire following psychological skills and performance enhancement strategies are structured in accordance widi the psychological characteristics displayed by suc­ cessful elite athletes discussed earlier in tiiis article. numerous sport psychology consultants have document­ ed d ie application o f tiiese techniques in preparation for and during olympic games.171" 1"-0-’1-it should be noted diat a psychological sldlls training programme cannot be expected to compensate for weaknesses or deficiencies in otiier parts of an atiilctes piogiamme (e.g. inadequate physical capacity, training programme, coaching etc).13 a psychological sldlls training pro­ gramme must be viewed as a critical p a il o f the athlet­ ic programme and the psychological input should be placed" in die perspective o f the athlete's life and the athlete’s daily functioning. a psychological skills train­ ing programme is a significant but only one of mail}’ parts o f an athlete’s sport experience.2 ' the sell-regulation ol arousal the inverted u-liypotliesis has been a popular theory to explain the relationship between arousal or anxiety and athletic performance. initially, performance improves widi increased arousal, up to a certain point, aiter whicli further increases in arousal produce a deteriora­ tion in performance. the critical point lias been referred to as the point o f optimal activation." ’4 the optimal level o f arousal varies as a function of die complexity of the task and the skill level of the ath­ lete. for example, for activities that require precise fine motor sldlls involving steadiness o f control o f uuwauted muscle activity (e.g. high-board diving), very little arousal can be tolerated without impairing perfor­ mance. however, for tasks that require minimal fine motor precision (e.g. weight lifting), a higher level ol arousal can be tolerated before performance is impaired.11 m ien atiiletes reach an optimal level o f arousal they should feel highly energised but still relaxed. this liigli energy state has frequently been described by elite ath­ letes as a feeling o f joy, ecstasy, intensity, boldness, inspiration, challenge, and being “ charged” or “ hot despite the heightened arousal level, athletes should be physically relaxed with tiieir muscles being loose and able to perform fluid movements. athletes who find tiiemselves in tiiis optimum level o f arousal will experience a sense ofim ier calm and a high degree o f concentration concurrent widi a time-space disorien­ tation (usually the sense o f time being slowed down). the fear o f failure is completely absent. sport scientists generally agree that most, perfor­ mance errors arise not so much from under-arousal, but rather from over-arousal, when atiiletes experience dif­ ficulties coping with competitive anxiety.2' thus, adi letcs need to learn self-monitoring and recognize how tiieir emotional slates affect their performance during competition. progressive relaxation jacobson advanced the concept o f progressive relax­ ation after observing that an anxious mind cannot exist within a relaxed body.27 relaxation o f a muscle group was found to be physiologically incompatible widi con­ traction o f that saine group. therefore, relaxation train­ ing was seen to combat the anxiety response by elimi­ nating tension in die muscles. progressive relaxation involves systematically con­ tracting and tiien relaxing one major muscle group in the body before progressing to the next muscle group while focusing 011 the different sensations o f tension and relaxation. with practice a person can detect ten­ sion in a specific muscle or area o f the body, like the neck, and then relax that muscle. the advantage o f the m ediod o f progressive relax­ ation is that atiiletes can t ake full control o f thenlevel o f arousal. an athlete who lias mastered the teelmique after several months o f regular pract ice should be able to elicit the relaxation response witliin seconds of encountering a stressful stimulus. 14 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) autogenic training autogenic training consists o f a series o f exercises designed to produce two physical sensations: warmth and heaviness. tlie feeling o f warmth is ascribed to ihe dilation o f tlie blood vessels with a resultant increase in blood flow, while die sensation o f heaviness is due to the relaxation o f muscle groups. it usually takes several months o f daily practice to becom e proficient in tlie use o f autogenic training. once mastered, it is especially useful for fast relaxation in a competitive environment and can be effectively applied in tlie field o f sport. concentration athletes must focus attention on tlie relevant cues in tlie environment and maintain tlie appropriate atten tional foci for the duration o f the competition. concentration problems are usually caused by an inap­ propriate attentional focus and occur when athletes becom e distracted by thoughts, emotions, or other events. tlie athletes should be focused 011 tlie present and be conscious only o f what they are doing at that specific moment. they should have 110 thoughts about the past or future because these are irrelevant cues that often impair concentration and lead to reduced performance. some athletes find it difficult to forget what has just happened, especially i f it was a bad mistake. thinking about die future usually involves focusing 011 die conse­ quences o f certain actions and often t akes tlie form o f “ what i f ’ questions, such as: “ what if i make another mistake?” or “ wliat if we lose tlie gam e?” .' " tims ath­ letes should have more task-oriented thoughts rather than a preoccupation with thoughts o f making m is­ takes. tlie appropriate attentional focus allows tlie athlete to be acutely aware o f liis or her own body and tlie sur­ rounding athletes. tlie athlete also has tlie sensation of being completely in harmony with die environment"". nideffer2" -views attentional focus along two dimen­ sions: width (broad versus narrow) and direction (inter­ nal versus external). these combine to give four differ­ ent types o f attentional focus. a broad attentional focus allows athletes to attend to several occurrences simul­ taneously. tliis is essential in sports where athletes have to be aware o f and sensitive to a rapidly changing environment and be able to respond to multiple cues (e.g. a hockey player leading a ball up tlie field). a nar­ row attentional focus is required when adilet.es have to attend to only one or two cues (e.g. pistol shooting). an external attentional focus shifts attention out ward 011 an object, such as a ball or an opponent’s movements (e.g. in a doubles temiis match). a 11 internal attentional focus is directed inward 011 thoughts and feelings (e.g. moni­ toring calf muscle tension). athletes must initially control tlie width o f their attention and decide whether to exclude or include tlie many environmental cues available during the competi­ tion. further, athletes must be able to control tlie direc­ tion o f their attention by either focussing inwards 011 their own feelings, dioughts and arousal level or focus­ ing 011 external cues such as the opponent or ball. athletes slioidd ideally be able to change their focus o f attention in accordance with die changing attentional demands during competition. self-talk self-verbalizations, expressed aloud or as thoughts, have a strong impact 011 a person’s behaviour. 'die actu­ al words used by athletes during self-talk influence tlie level o f performance. performance levels o f elite ath­ letes can be improved through thought processes and thought content alone without increased physiological efforts or energy costs.” self-talk can be positive or negative. positive self-tall?; enhances the self-esteem, motivation, attentional focus and performance o f athletes. self-talk tliat helps ath­ letes focus 011 tlie present and prevents their mind from wandering is viewed as positive. it usually has either a motivational component, (e.g. “ i can do it” ) or an instructional component (e.g. “ keep yoiir eyes 011 tlie ball” ). on the other hand, negative self-talk is critical and demeaning and impairs the realization o f goals. negative sell-talk (e.g. “ tliat was a stupid mistake” ) creates anxiety and self-doubt." -7 thoughts play a crucial role in mediating emotional leactions to situations, and these reactions influence future behaviour. events in and o f themselves do not cause negative emotional reactions (e.g. depression, anger, anxiety, hopelessness or frustration). rat her it is how athletes interpret the event that determines their response." self-talk may be used by atldetes to acquire new skills, change bad habits, initiate action (e.g. numcrs can increase their speed by using cue words sueli as “ fast”) and sustain effort when the athlete feels tired (c.g “ keep it up” , “ liang in there” ). " several tccliniques can be used to improve self-talk. one strategy to deal with negative thoughts is to stop diem before they impair performance. athletes are trained to stop negative thoughts as soon as th ey arise by using a cue word (such as “ stop” ) or any physical trigger (such as snapping fingers or hitting a hand against a thigh) and then focus 011 a task-related cue."--'7 it is however not possible to eliminate all negative self-talk. another way to deal with negative self-talk " h e n it occurs, is to change the negative thoughts into positive thoughts, which refocuses the athlete’s atten­ tion to provide encouragement and motivation and which brings the athlete back into die present to take control o f the event. for example, “ i never play well when the wind blows” can be rephrased into “ nobody lilies to play in windy conditions, but i will perform at my personal best” ."-7 cue words can also be used to set in motion a specif­ ic 1 espouse. they can be used as an instruction (e.g. follow-through ’ , “ watch die ball” ) or to motivate (e.g. strong ’ , “ relax” , “ get tough” ). tlie cue word should be simple and should automatically trigger the planned reaction. for example, gymnasts performing a floor routine can say the word “ forward” to ensure tliat they push ahead at a specific [)oini dining their routine. sprinters can say “ explode” to ensm c that tlicv get out of die starting block quickly atliletes must practice using these cue words so tliat they become habitual and well-learned before being utilized during competition. cue words are helpful when atliletes me trying to change a movement sequence or when trying to change an ingrained habit." sports medicine july 1996 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) high se lf confidence atiiletes’ performance is enhanced as tiieir level ol self confidence increases up to an optimal point alter which future increases in self-confidence result in impairment o f performance. atiiletes lacking self-confidence doubt tiieir capabili­ ty to perforin tlie skills under pressure during the com ­ petition. self-doubts hinder atiiletes’ performance by causing anxiety, reducing concentration and creating indecisiveness. atiiletes lacking self-confidence locus on their weaknesses rather than on tiieir strong points and distract their attention away from the task that has to be completed. on the other hand, the performance of atiiletes who are overconfident (tiieir confidence is greater that tiieir abilities justify) may deteriorate because they think tliat they do not have to prepare them selves for the event or expend the effort to com ­ plete the task.” atiiletes with optimal self-confidence are charac­ terised by a positive attitude and feelings o f optimism.21' they are able to keep poise and feelings ol strength and control even during adversity or potentially threatening situations. the atiiletes are in control o f their actions and o f the environment.2 the performance seems to be automatic and effortless. many potential benefits for athletes arise from a feel­ ing o f high self-confidence. confident athletes arc more likely to stay calm and relaxed tmder pressure. confidence facilitates concentration so that the atiiletes can focus on die task at hand. confident atiiletes tend to set challenging goals and pursue them actively and with increased vigour. confident athletes tend to play to win and are usually not afraid to take chances. confidence helps atiiletes deal more effectively with errors and mistakes." goal-setting a good method to improve atiiletes’ confidence is to set effective goals that provide direction and enhance moti­ vation.8 it is important diat atiiletes understand the dif­ ference between outcome goals and performance goals. outcome goals stress the competitive rcsidt o f an event, such as winning a competition or game. atiiletes with this orientation are concerned about winning or losing rather than thinking about the quality' o f tiieir perfor­ mance. achieving outcome goals therefore depends not only on the athletes’ own efforts but also on the abilities and performance o f tiieir opponents. outcome goals are therefore counter-productive, because they often emphasize aspects that cannot be controlled by the atli letes (especially in team sports). when atiiletes are too concerned about outcome goals, this causes anxietyr dur­ ing competition, and the atiiletes worry unnecessarily instead o f concentrating on the task. on the other hand, performance goals focus on realizing performance objec­ tives that are compared with the atiiletes’ own previous performance and therefore do not focus on the outcome o f the event.8-*1 goal setting is a very good method for improving ath­ letes’ performance i f implemented correctly, h i order to promote behavioural change, goals must be specified in a measurable way and in behavioural terms, h i order to be effective, goals must b e set difficult enough to chal­ lenge the athletes, yet realistic enough to be achiev­ able. short-term goals should be used as a method to achieve long-term goals and should be recorded and kept in a visible place. strategies or plans must be outlined to achicve the goals diat have bceu set. athletes must be part, o f the goal setting process which needs, to b e constantly mon­ itored and evaluated. regtdar performance feedback and support from significant others is important, if goal setting is to be effective. imagery j'h c terms mental practice, imagery, visualisation and mental rehearsal are used interchangeably to relate an athlete’s mental preparation for competition. imagery is the use o f visualization to imagine situations. internal imagery makes it possible for atiiletes to kiues tlietically experience the correct execution of a skill, while external imagery lets them see themselves per­ forming tlie skill.2'1 atiiletes can use imagery to recreate past experiences or visualize future new events to ready themselves men­ tally for performance. when using imagery, the athlete needs to involve as many senses as possible in order to create life-like images. it is also important to generate the emotions or moods associated with specific tasks or sldlls that are being imagined. athletes should pay attention to environmental detail (e.g. layout o f the facilities, closeness to specta­ tors) and recreate tlie atmosphere o f the actual compe­ tition. man}r olympic teams visit tlie actual competition sites months in advance to familiarize themselves with tlie siutotuidings so that they can visualize themselves performing in that exact setting, with its specific colour, layout , lighting and construct ion. atiiletes can use imagery to improve botii physical and psychological sldlls. concentration may be enhanced by athletes imagining themselves in situa­ tions where they generally lose concentration and then visualizing them selves remaining com posed and focused. imagery can be used to build confidence in athletes. they can imagine situations that have caused problems in die past and then picture themselves cop­ ing positively with these events. the best-known use o f imagery is practising particidar sport skills in detail (e.g. tluowing a javelin) repetitively to line tune diem or identify wealaiesses and visualize correcting them. for imagery to be incisive, it needs to be practised as part aud parcel o f an athlete’s daily routine. at the beginning, it is best to practise in a setting with 110 dis­ tractions. with practice, athletes learn to use imagery amid distractions and even in actual competitions. the time spent imagining a particular skill should eventual­ ly be equal to the time die sldll actually takes to occur in order to improve the transfer from imagery to real life situations. d e t e r m in a t io n , c o m m i t m e n t a n d control determination,"commitment and self-control have been recognized as key psychological ingredients for sporting excellence.™’ few athletes can achieve high levels of exccllcnce without complementary high levels o f per­ 16 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sonal determination and commitment. achieving tlie tdtimate standard possible requires an athlete to make sacrifices: to train harder and longer, to expend more time and effort during practices.' or licit and partington’" stated that for the m ost successful canadian olympic atiiletes at tlie 1984 olympics excel­ lence in sport was tlie top priority in tiieir lives: every­ thing revolved around their sport. they were complete­ ly committed atiiletes with clearly defined success goals. tlie emphasis was 011 quality training, bolstered by pre-set individualized training goals and a clear com ­ mitment to follow tiieir plans. to achieve real athletic success, maturity and self control are essential. being able to react effectively in big games and tight situations as well as in normal games requires confidence and composure. conclusion refining and perfecting mental sldlls takes life-long practice.11’ it is a tedious, tim'e-consuming effort. just as physical training is. only a sclect few will bring all com ­ ponents together consistently. they are the elite. yet each and every athlete can learn, apply and grow through the inclusion o f psychological sldlls training hi tiieir athletic life, at whichever level they choose to compete. for those at tlie top tlie choice is clear. psychological sldlls training is a must to be part o f the olympic experience. to be part o f tlie experience o f excellence. reflecting on tlie sport psychology services provided to the us team at tlie 1988 summer olympics in seoul, murphy and ferrante*' concluded: “at a 1110111 cut when tlie whole world seem ed focused on winning versus los­ ing, we becam e even more committed to our basic ph i­ losophy o f helping each individual learn and grow as a function o f h is/h er olympic experience” . references 1. williams jm. p sychological characteristics o f p ea k perfor­ m ance.in: williams jm, ed., a pplied sport psychology: p ersona l g row th to p ea k p erform ance. p a lo a lto , california-.mayfield publishing company, 1986: 123-132. 2■ van-den a u w eele y, d e cuyper b, van mele v, rxewnicki r. elite perform ance and personality: from description and prediction to diagnosis and intervention. in: singer, rn., murphey, m., tennant, lk ., eds., h andbook o f r esearch on sport p sych ology. new york: m acmillan publishing company, 1993:257-289. 3. rushall, bs. sport psychology: the key to sporting excel­ lence. international journal o f sport psucholoaii, 1989; 2 0 ( 3 ) : 165-190. 4. gould d. eklund rc, jackson .s71. 1988 us. olympic wrestling excellence: i. m ental preparation, precom petitive cognition, and affect. the sport psychologist, 1992; 6: 358 -382. 5. gould d, 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p sychologist 1989: 3: 320-329. 24. gould d, krane v. the arousal-athletic perform ance relationship: current sta tu s and fu tu re directions. in: horn ts, ed. a dvan ces in sport psychology. champaign. illinois: human k in etics publishers, 1992: 119-142. 25. loehr je. h ow to overcom e stress and p la y at you r peak all the time. tennis 1984; march: 66-76. 26. garfield ca, b en n ett hz. p ea k p erform an ce:m ental training techniques o f the world’s g reatest a thletes. los a ngeles: tardier, 1984. 27. schom er h ii. p sych ologica l training techniques fo r ath letes. in: p o tg ie ter jr, ed. r ead in gs in sport psychology. university o f stellenbosch:institute fo r sport and movement studies. 1992; 1-11. 28. n ideffer rm. a th le te s ' g uide to m ental training. champaign. illinois: human k in etics publishers. 1985. 29. cox rh. sport psychology: concepts and a pplications. 3rd edition: dubuque, iow a: brown & benchmark. 1994. 30. orlick t. in p u rsuit o f e xcellen ce. champaign. illinois-.human kinetics, 1980. 31. orlick t, partington j. mental links to excellence. the sport psychologist 1988; 2: 105-130. 32. murphy sm, ferrante a p provision o f sport p sych ology ser­ vices to the us team at the 1988 summer olympic gaines. tlie sport p sychologist 1989: 3: 374-385. q sports medicine july 1996 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) national olympic committee of south africa (nocsa) anti-doping policy april 1996 dr g ruijscli van dugteren mb clib fcp 1. interpretation in tliis policy, tlie following words have the following respective meanings: "nocsa" tlie national olympic committee o f south africa. "ids" tlie institute for drug-free sport "agency" any agency throughout tlie world recog­ nised by nocsa as conducting sampling or testing, or both, o f atliletes for tlie detection o f doping and in accordance with tlie ioc medical code; "nsc" the national sports council "athlete" (a) a member or potential member o f a south african olympic team; (b) a member o f a nocsa affiliate or per­ son competing in any competition under tlie control or auspices o f a nocsa affiliate; (c) a person competing in any competition in south africa contested in tlie frame­ work o f tlie olympic movement, in partic­ ular those competitions organised undcr tlie authority, whether direct or delegat­ ed, o f an international federation, nocsa or a nocsa affiliate. "doping" is defined as: (a) the administration o f substances belonging to proliibited classes o f phar­ macological agents; and/or (b) tlie use o f various proliibited mediods as described in chapter ii o f tlie ioc medical code (as in force from time to time). "if" an international federation being a body controlling a branch of sport and recog­ nised as such by hie ioc. "ioc" tlie international olympic committee, being an association created by the congress o f paris o f 23 june 1984 and which is entrusted with tlie control and developm ent o f the m odern olympic games pursuant to the olympic charter. "ioc tlie medical code provided for under medical code” ride 48 o f the olympic charter. "affiliate" any body which is affiliated to nocsa. "olympic the olympic charter o f the ioc charter" or any amendment, m odification or replacement thereof. "responsible hie ioc, ifs, nocsa, nsc, ids, nfs and authority" nocsa affiliates. trafficking occurs when any person: (a) manufactures, extracts, transforms, prepares, stores, expedites, transports, imports, transits, offers (subject to pay­ ment or free o f charge), distributes, sells, exchanges, brokers, obtains in any form, prescribes, commercialises, makes over, accepts, possesses, holds, buys or acquires in any manner products or sub­ stances which are prohibited under die ioc medical code; (b) acts in this respect, finances or serves as an intermediary for the financing o f die latter, provokes in tiny way tlie con­ sumption or use o f such products or pro­ hibited substances or establishes means o f procuring or consuming such sub­ stances; or (c) is concerned or involved in methods which are prohibited by die ioc medical code, other than in die course o f die legal cxercise o f professional activities. any words when used in the plural shall have a corre­ sponding meaning in hie singular. any words used in die masculine gender shall have a corresponding meaning in tlie feminine gender. words not defined in tiiis policy shall have the meaning ascribed to diem in the constitution o f nocsa unless a contrary meaning appcai-s from die context . 2. position statement 2.1 the ioc's medical code (olympic charter ride 48) (i) provides for the prohibition o f doping, (ii) determines die classes o f prohibited sub­ stances and proliibited m ediods, (iii) establish­ es die list o f accredited laboratories, (iv) pro­ 18 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) vides for tlie obligation o f competitors to submit themselves to medical controls and examina­ tions, (v) lays down testing procedures, includ­ ing procedures for selection o f athletes, sample collection and sample analysis, (vi) provides for appeals to tlie court o f arbitration for sports, (vii) determines sanctions to be applied in tlie event o f a doping violation and (viii) prohibits the trafficking in prohibited substances. 2.2 on 13 january 1994 representatives o f tlie ioc, the association o f summer olympic international federations, tlie association of international winter federations, ifs, the association o f national ofympic committees, the continental associations o f nocs and athletes agreed, among other tilings: ( 1 ) to imify their anti-doping ndes and proce­ dures for the doping controls performed both during and out o f competition; (2) to adopt, each year, as a basic document tlie list o f proliibited classes and methods of doping established by tlie ioc m edical commission and to undertake tlie necessary controls for each sport; (3 ) to accelerate unification o f tlie minimum sanctions provided for by the ioc medical commission for violations o f tlie anti-doping reg­ ulations and to ensure their application at botii international and national level; (4) to recognise tlie sanctions imposed by an if; (5) to use laboratories accredited by tlie ioc for all international competitions and out o f compe­ tition testing; and (6) to develop co-operation between tlie ioc, ifs, nocs, national federations and govern­ ments or other organisations concerned in order to organise and ca n y out doping controls and to combat tlie trafficking o f proliibited substances in sport. 2.3 tire ioc medical code and tliis policy are essen­ tially intended to safeguard tlie health o f atli­ letes and to cnsiue respect for tlie ethical con­ cepts implicit in fair play, tlie olympic spirit and medical practice. 2.4 doping is proliibited 2.5 all atliletes must provide samples for testing at the request o f a responsible authority or agency 2.6 tlie counselling o f tlie use of, permitting tlie use of, or condoning die use o f any substance or method contrary to tlie ioc medical code is pro­ hibited. 3. application of anti-doping policy 3.1 tliis policy applies to: (1) athletes, whether in or out o f competition; (2) coaches, trainers, officials, and medical and paramedical personnel worlting with or treating adiletes; (3) nocsa affiliates; and (4) all persons involved in trafficking. 3.2 sanctions are applicable in tlie event o f any breach o f the provisions of this policy. 4. dope testing 4.1 nocsa or an agency may conduct sampling and testing or both o f athletes for the detection o f doping. 4.2 a responsible authority may select an atlilete to provide any number of saniplcvs for dope testing in a year, whether in or out o f competition. 4.3 sampling and testing o f adiletes must be con­ ducted in conformity with the ioc medical code. 4.4 minor irregularities which cannot reasonably be considered to affect the results o f otherwise valid tests, will not invalidate such results. however, tests may be invalidated in die case of serious irregularities such as a break in the chain o f custody o f die sample, improper scaling o f the container in which die sample is stored, f ailure to request tlie signature o f the athlet e, or failm-e to provide die atlilete with an opportuni­ ty to be present or be represented tit the opening and analysis o f the "b" sample. 4.5 every nocsa affiliate must: (1) pennit nocsa or an agency to attend com ­ petitions conducted by it, or under it's auspices, in order to obtain samples for dope testing; (2) perm it nocsa or an agency to obtain samples for testing from athletes out o f compet­ ition and provide reasonable assistance for this purpose. (3) infonn adiletes tliat tiiey are liable for selection to provide samples for dope testing whether in soudi africa or overseas; (4) arrange for completion and return o f fomis required for dope testing purposes at the request o f nocsa, an agency or a responsible authority; (5) require and cause atliletes and officials to pennit nocsa or an agency to collect samples for testing out o f competition and provide rea­ sonable assistance for tliis purpose; (6) use nocsa or an agency to conduct :uiy additional test required by the nocsa affiliate sports medicine july 1996 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ill south africa at its own expense; (7) submit its anti-doping policy to nocsa for approval o f consistency with its policy and there­ after not alter or amend its approved anti-doping policy without first obtaining tlie approval of nocsa. 5. other doping offences 5.1 should an athlete fail or refuse to provide a sample upon request, then this will be an infraction o f this policy and for which tlie athlete is subject to tlie same penalty as i f tlie athlete had committed dophig. 5.2 where an athlete has made a statement admit­ ting doping such statement will be prima facie evidence o f an infraction o f this policy'. upon notification o f such a statement, the seeretan' -general may conduct enquiries as he or slie deems appropriate to determine whether there is sufficient evidence that the statement of admission o f doping was made. in conducting these enquiries, nocsa will not be obliged to conduct any hearing or to receive any evidence or statenieuts by or on b eh a lf o f the athlete concerned. 5.3 should a nocsa affiliate fail to adopt and implement an anti-doping policy' consistent with this policy, it will be in breach o f nocsa’s constitution and this policy and liable for tlie penalties described therein for a breach o f tlie constitution or by-laws made thereunder. 5.4 trafficking is prohibited and any person (includ­ ing ail}7 bod}7, corporate or unincorporate) involved hi trafficking is liable to sanction under this policy. 5.5 any person will be deem ed to be involved in trafficking if that person: (1 ) has aided, abetted, counselled or procured tlie trafficking; (2) has induced, whether by threats or promis­ es or otherwise, tlie trafficking; (3) has been in any way, directly or indirectly, knowingly concerned in, or party to, tlie traffick­ ing; or (4) has conspired with others to effect tlie trafficking. 5.6 clauses 5.4 and 5.5 do not apply to doctors, pharmacists and other members o f tlie medical profession or holders o f analogous diplomas recognised by tlie public authorities concerned, when one or other o f tlie above clauses is neces­ sary for them within the strict limits o f exercis­ ing tlie art o f healing. 6. advice of alleged breach 6.1 where nocsa has requested an agency or agencics to conduct sampling or testing or both o f atiiletes, that agency or agencies will notify nocsa o f tlie names and results o f any athlete who returned a positive test result or who failed to comply with tlie requirement to provide a sample for testing. 6.2 affiliates must notify nocsa o f tlie names and result o f any athlete who returned a positive test result or who failed to comply with a requirement to provide a sample for testing. other responsible authorities may so notify nocsa. 6.3 atiiletes and affiliates must notify nocsa o f tlie names o f any person who they know or reason­ ably suspect o f being involved hi trafficking, and must provide nocsa with all such information and assistance as they are able to give to enable nocsa to conduct an investigation into the circumstances surrounding the suspected trafficking. failure to do so will be considered trafficking by tlie athlete or nocsa affiliate concerned. 6.4 nocsa will maintain confidentiality o f informa­ tion provided under clauses 6.1, 6.2, and 6.3 mitil after a decision (if any) to impose a sanction for a breach o f this policy has been determined except as is necessary to conduct or prosecute any hearing under this policy or to notify the relevant responsible authorities. 7. notification of alleged breach by an athlete or other person 7.1 where nocsa receives notification from an agency or a responsible authority that an athlete has returned a positive test result or has failed to comply with a request to provide a sam­ ple or for another reason believes that a person to whom tiiis policy applies has committed an infraction o f this policy, nocsa will give to the athlete or person concerned notice o f the alleged infraction. 7.2 this notice o f alleged infraction (clause 7.1 above) must: (1 ) b e hi writing and be delivered to the athlete or person; (2) set out tlie nature and particulars o f tlie alleged infraction; (3) set. out or enclose an extract o f tiiis policy relating to tlie sanctions that may be imposed if it is determined that tlie alleged infraction has occurred, tuid (4) state that a hearing to decide whether an infraction o f this policy lias occurred and what penalty' to impose will b e determined by a 20 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) committee appointed by the ids according to the procedures described in clause 9. 8. olympic games 8 1 tlie ioc executive board is the only body competent to rule on tlie effects o f a positive test result during the olympic games. 8.2 should an atlilete be found by the ioc' executive board to have committed doping dining the olympic games, any hearing by a committee appointed by nocsa or any appeal therefrom to tlie court o f arbitration for sport will be bound hy that finding and the hearing or appeal will be limited to the sanction to be imposed for the breach o f tliis policy. 9. procedure for the conduct of hearing into doping 9.1 where nocsa gives an atlilete or person a notice pursuant to clause 7, nocsa will consult with die affiliate o f tlie atlilete or person concerned with a view to there being a joint hearing on beh alf o f nocsa and tlie affiliate to determine: (1) whether the atlilete or person has commit­ ted an infraction o f tliis policy and/or tlie anti doping policy o f tlie nocsa affiliate; (2) what sanction consistent with tliis policy should be applied to the atlilete or person who was found to have committed an infraction o f this policy. 9.2 should it not be possible or feasible to conduct a joint hearing pursuant to clause 9.1, the hearing will be on behalf o f nocsa alone. 9.3 tlie nocsa executive will appoint a committee o f up to three persons to conduct a hearing. 9.4 tlie committee may conduct a hearing in such a manner as it determines. hearings may be conducted by telephone or other conference facilities. 9.5 hearings are to be conducted with as littie formality and technicality, and with as much expedition, as proper consideration o f the matter before tlie committee permits. 9.6 at a hearing o f tlie committee: (1) tlie committee may examine and cross examine witnesses and may appoint a legal representative or other person to assist it; (2) nocsa and, if tlie hearing is a joint hearing on beh alf o f nocsa and an affiliate, that affiliate, may separately or jointly examine and cross-examine witnesses and be assisted by legal representation or other person; (3) the atlilete or person concerned may exam­ ine and cross-examine witnesses and may be assisted by a legal representative or other person; and (4) where an atlilete contends that, sampling or testing or both o fliin i or her is not substantially in conformity with the ioc medical code, die onus shall b e on the athlete to show on tlie balance o f probabilities that liis or her con­ tention is correct and tliat as a result thereof the results o f (lie sampling and testing have been so affected as to not record doping. 9.7 tlie committee will make a statement in waiting stating its findings o f fact and its decision and will send tlie statement to nocsa. the committee is not bound to give a statement o f its reasons for its decision. 9.8 nocsa will send a copy o f (lie statement to: (1) die ioc (2) tlie ids (3) tlie nsc (4) the affiliate o f which the atlilete or person is a member; and (5) any other person or organisation that nocsa believes should be informed. 9.9 tlie committee will send to the athlete or person concerned a copy o f die statement so far as it relates to die atlilete or person, but the atlilete or person is not entitled to a copy o f the committee's statement o f its reasons (if any). 10. appeals 10.1 an atlilete or person who is dissatisfied with a decision made in relation to him or her under tliis policy may, within 14 days o f receiving written notification o f (lie sanction imposed, appeal to the court o f arbitration for sport and request tliat an appeal be conducted in relation to: (1) tlie determination that an infraction o f diis policy has occurred and die imposition o f the sanction; or (2) the sanction that has been imposed. 10.2 auy such appeal will be conducted according to tlie code o f sports-related arbitration. 10.3 an appeal deals only with die original matters appealed against. 10.4 upon receiving notice o f (lie outcome o f an appeal from tlie court o f arbitration for sport., nocsa will give written notice o f tlie outcome to: sports medicine july 1996 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ( 1 ) tlie athlete or person making tlie appeal; and (2) tlie persons and/or organisations provided with tlie statement pursuant to clause 9.7. 10.5 an appeal conducted hi accordance with diis policy is tlie sole form o f appeal from tlie decision under this policy. no appeal may be made to a court or other tribunal. 11. sanctions 11.1 any atlilete who is found to have committed doping will be ineligible for membership o f or selection in any south african olympic team, or to receive funding from or to hold any position on nocsa as follows: ( 1 ) for a first infraction other than cases provid­ ed for hi paragraph (2) suspension for two years. (2) for a first infraction hi cases o f a positive result for ephedriue, plienylpropanolaniiuc, pseudo-ephedrine, caffeine, strychnine and related compounds suspension for a maximum period o f three months; (3) for tlie second offence other than hi tlie cases provided hi paragraph (4) suspension for liis or her lifetime; (4) for a second infraction in cases o f a positive result for ephedriue, phenylpropanolamine, pseudo-ephedrine, caffeine, strychnine and related compounds suspension for two years. (5) for a subsequent infraction hi cases o f a positive result for ephedriue, phenyl­ propanolam ine, pseudo-ephedrine, caffeine, strycluiine and related compounds suspension for his or her lifetime. 11.2 where an atlilete or other person to whom tiiis policy applies is found to have committed an infraction o f tiiis policy other than doping he or she will be subject to at least tlie same penalties as described in clause 1 1 .1 , provided that such penalties are a minimum only and may be increased according to tlie circumstances and culpability involved. 11.3 tlie above sanctions may be applied to a person regardless o f any sanction or penalty, its duration or timing or whether current or past, imposed by any responsible authority provided that nocsa will recognise previous sanctions imposed by any responsible authority to deter­ mine whether tlie breach is a first or second offence. 11.4 nocsa will, however, recognise sanctions imposed by a relevant if if its sanctions extend for a longer period than that imposed by nocsa. 11.5 failure by an invited atlilete or person to attend to be heard by the committee in accordance with clause 9 for whatever reason will not invalidate tlie right o f nocsa to impose a sanction hi accordance with ill is policy. 12. press release a press release may be issued by nocsa in relation to ail}sanction imposed under this policy. 13. review of sanction 13.1 where an atlilete or person to whom a sanction has been applied under this policy has new and relevant information concerning the infraction, he or she or it may make written application to nocsa setting out the grounds for a possible review o f diat sanction. the executive o f nocsa may consider the application and determine hi its sole and absolute discretion to either: (a) itself review any sanction imposed imder this policy and whether to alter a decision made previously including a reduction or withdrawal o f die sanction; or (b) refer the matter to the court o f arbitration for sport for that court to determine whether to review any sanction imposed under this policy and whether to alter a decision made previously including a reduction or withdrawal o f the sanction. 13.2 nocsa will not alter any decision under clause 13.1 without first consulting with any otlier sports organisation which it knows has a current sanction over the atlilete or person and obtains its agreement, to the alteration. 13.3 notification o f any change to the previous decision will be made hi accordance with clause 11. 14. education and other initiatives nocsa will undertake die following anti-doping initia­ tives: (1) support die anti-doping policies o f the government through tlie institute for drug-free sport. (2) enc.oiu-age the development and implementation by responsible authorities o f drug education programmes for atiiletes and officials. (3) support the information and educational initia­ tives o f responsible authorities. q] 22 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) south african institute for drug-free sport international olympic committee medical commission proliibited classes of substances and prohibited methods january 1996 doping contravenes tlie ethics o f sport and medical science. doping consists of: 1. tlie administration o f substances belonging to selected classes o f pharm acological agents, and/or 2. tlie use o f various prohibited methods. i. prohibited classes of substances a. stimulants b. narcotics c. anabolic agents d. diuretics e. peptide and glycoprotein hormones and ana­ logues ii. prohibited methods a. blood doping b. pharmacological, chemical and physical manipu­ lation iii. classes of drugs subject to certain restrictions a. alcohol b. marijuana c. local anaesthetics d. corticosteroids e. beta-blockers examples and explanations tliis document lists examples representing different doping classes to illustrate tlie doping definition. no substances belonging to the banned classes may be used even i f tlie}are not listed as examples. for diis reason, tlie term “ and related substances” is intro­ duced. tliis term describes drugs tliat are related to tlie class by their pharmacological actions or chemical structure. a longer list o f examples belonging to differ­ ent pharmacological classes o f banned substances can be found in annex 1. if substances o f tlie banned classes are identified by an ioc accredited laboratory tlie relevant authority will act. i. prohibited classes of substances a. stimulants stimulants comprise various types o f substances which increase alertness, reduce fatigue and may increase competitiveness and hostility'. their use can also pro­ duce loss o f judgement, which may lead to accidents to others in some sports. amfetamine and related com ­ pounds have the most notorious reputation in produc­ ing problems in sport. some deaths o f sportsmen have resulted even when normal doses have been used under conditions o f maximum physical activity. there is 110 medical justification for tlie use o f “ amphetamines” in sport. one group o f stimulants is die sympathomimetic amines o f which epliedrine, pseudoephedrine, phenyl­ propanolamine and norpseudoephedrinc are examples. in high doses, tliis type o f compound produces mental stimulation and increased blood flow. adverse effects include elevated b lo od pressure and headache, increased and irregular heart beat, anxiety and tremor. these compounds are often present in cold and hay fever preparations which can be purchased “ over tlie counter” from pharmacies and sometimes from other retail outlets without medical prescription. another group o f stimulants is tlie beta-2 agonists. these drugs are unusual because diey are classified as botii stimulants and anabolic agents. when taken by mouth or by injection they may exert powerful stimula­ tory and anabolic effects. oral and injectable adminis­ tration o f beta-2 agonists is banned. of tlie beta-2 agonists only salbutauiol, salmetcrol and terbutaline arc permitted and only by inhalation. any physician wishing to administer beta-2 agonists by inhalation must give written notification to tlie relevant medical authority prior to tlie competition. the choice o f medications to treat asthma and other common, respiratory disorders poses a problem because some o f tlie more commonly prescribed substances are powerful stimulants. furthermore, because these drugs have many different product names, tlie status o f a ding' may be confusing. tlie most prudent, approach is never to take or prescribe a product-for colds, sore throats, and flu without first checking with a physician or phar­ macist who has special expertise in tliis area. prohibited substances in class (a) include the fol­ lowing examples: amiphenazole amineptine cocaine fencamfamine pentylentetrazol salbutamol* * salmetcrol ** . . . and related substances. * caffeine: tlie definition o f a positive depends 011 tlie concentration o f caffeine in tlie urine. tlie concentra­ tion in urine may not exceed 1 2 micrograms per milliliter. * * salbutamol, sahneterol and terbutaline are permit­ ted by inhaler only and must be declared in writing, prior to die competition to tlie relevant medical author­ ity. note: all imidazole preparations are acceptable for topical use, e.g. oxymctazoline. vasoconstrictors (e.g. adrenaline) may be administered with local anaestlietain phetamines caffeine * ephedrines mesocarb pipradol terbutaline * * sports medicine july 1996 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ic agents. topical preparations (e.g. nasal, ophthalmo logical) o f phenylephrine are permitted. b. narcotics morphine and other compounds o f tiiis class are pow­ erful analgesics and are mainly used for tlie manage­ ment o f severe pain. these substances have major side effects, including respirator}7 depression, and they carry a high risk o f physical and psychological dependence. evidence reveals that narcotic analgesics have been abused in sports. therefore tlie ioc medical commission has issued and maintained a ban 011 their use. tlie ban is consistent with international restric­ tions and with the regulations and recommendations o f tlie world health organisation regarding narcotics. prohibited substances in class (b) include the following examples: dextromoramide dextropropoxyphenc diamorphine (heroin) methadone morphine pentazocine pethidine . . . and related substances note: codeine, dextromethorphan, diliydrocodeine, diphenoxylate and pholcodine are permitted. c. anabolic agents the anabolic class includes anabolic androgenic steroids (aas) and beta-2 agonists. 1. anabolic androgenic steroids (a a s ) tlie aas class includes testosterone and substances that are related in structure and activity to it. they have been misused in sport to increase muscle strength and bulk, and to promote aggressiveness. the use o f aas is associated with adverse effects 011 tlie liver, skin, car­ diovascular and endocrine systems. they can promote tlie growth o f tumours and induce psychiatric syn­ dromes. i11 males aas decrease the size o f die testes and diminish sperm production. females experience mas culinization, loss o f breast tissue and diminished men­ struation. tlie use o f aas by teenagers can stunt growth. prohibited substances in class (c l) include tlie follow­ ing examples: clostebol fluoxymesterone metandienone metenoloiie liandrolone oxandrolone stanozolol testosterone * . . . and related substances * tlie administration o f testosterone is banned .tlie presence o f testosterone (t) to epitcstosterone (e) ratio greater than six (6) to one (1 ) in tlie m ine o f a competi­ tor constitutes an offence unless there is evidence that this ratio is due to a physiological or pathological con­ dition, e.g. low epitestestosterone excretion, androgen production by tumour, enzyme deficiencies. in the case o f a t /e ratio higher than 6 , it is mandato­ ry that tlie responsible authority conduct an investiga­ tion before tlie sample is declared positive. a full report wall be written and will include a review o f previous tests, subsequent tests and any results o f endocrine investigations. in die event that previous tests arc not available, tlie athlete should be tested unannounced at least once per month for three months. the results o f these investigations should be included in the report. failure to cooperate in die investigations will result in declaring the sample positive. 2. beta-2 agonists when given syst eniically, beta-2 agonists may have pow­ erful anabolic effects, and tiieir use is therefore banned. (see also section ia) prohibited substances in class (c 2) include the follow­ ing examples: clenbuterol salbutamol terbutaline salmetcrol fenotcrol . . . and related substances d. diuret ics diiu-etics have important therapeutic indications for the elimination o f fliuds from the tissues in certain padiological conditions and for management o f high blood pressure. diuretics are sometimes misused by competitors for two main reasons, namely: to reduce weight quickly in sports where weight cat­ egories are involved, and to reduce die concentration o f substances by diluting the urine. rapid reduction o f weight in sport cannot be justified medically. health risks are involved in such misuse because o f serious side-effects which might occiu\ furthermore, deliberate attempts to reduce weight ar­ tificially in order to compete in lower weight classes or to dilute urine constitute clear manipulations which are unacceptable 011 ethical grounds. for sports involving weight classes, the responsible authorities reserve die right to obtain urine samples from die competitor at the time o f the weigh-in. prohibited substances 111 class (d) include the following examples: acetazolamide bumetanide chlorthalidone cdiacrynic acid furosemide hydrochlorothiazide mamiitol mersalyl spironolactone triamterene . . . and related substances e. peptide and glycoprotein liormones and analogues prohibited substances in class (e) include tlie following examples: 1. chorionic gonadotrophin (hcg-human chori­ onic gonadotrophin): it is well knowrn that die administration to males of human chorionic ganodotropllin (hcg) and odier coni poimds widi related activity, leads to an increased rate o f production o f endogenous androgenic steroids and is considered equivalent to the exogenous administration o f testosterone. 24 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 2. corticotrophin (a c t h ): corticotropliiii lias been misused to increase tlie blood levels o f endogenous corticosteroids notably to obtain tlie euphoric effect o f corticosteroids. tlie application o f corticotropliiii is considered to b e equivalent to the oral, lntra-mu scalar or intravenous administration o f cor­ ticosteroids. (see section iii. d). 3. growth hormone (hgh, somatotrophin): h ie misuse o f growth hormone in sport is unethical and dangerous because o f various adverse effects, for exam­ ple cardiomyopathy, hypertension, diabetes niellitus, and acromegaly when given in high doses for a long period o f time. contamination o f some growth hormone preparations o f human origin can cause creutzfeldt jacob disease (a fatal neurological condition). note: all tlie respective releasing factors o f the above mentioned substances are also banned. 4. erythropoietin (epo): tliis naturally occurring hormone is produced in the kidney and regulates red b lood cell production. synthetic epo is currently available and has been demonstrated to induce changes similar to blood dop­ ing (see iia). ii. prohibited methods the following procedures are proliibited: a. blood doping blood doping is tlie administration o f blood, red blood cells or related products to an atlilete. tliis procedure may be preceded by withdrawal o f blood from the ath­ lete who continues to train in tliis blood depleted state. these procedures contravene tlie ethics o f medicine and o f sport. there are also risks involved in the trans­ fusion o f blood and related blood products. these include tlie development o f allergic reactions (rash, fever etc.) and acute haemolytic reaction with kidney damage if incorrectly typed blood is used, as well as delayed transfusion reaction residting in fever and jaun­ dice, transmission o f infectious diseases (viral hepatitis and aids), overload o f tlie circulation and metabolic shock. b. pharmacological, chemical and physical manipulation pharmacological, chemical and physical manipulation is tlie use o f substances or o f methods which alter, attempt to alter or may reasonably be expected to alter tlie integrity and validity o f urine samples used in dop­ ing controls. examples o f banned methods include, without limitation, catheterisation, urine substitution and/or tampering, inliibition o f renal excretion such as by probenecid and related compounds, and epitestos terone administration. tlie ioc medical commission bans tlie use o f sub­ stances and o f methods which alter tlie integrity and validity o f urine samples used-in doping controls. i f tlie epitestosterone concentration is greater than 200 ng/nd, tlie laboratories should notify tlie appropri­ ate authorities. the ioc medical commission recom­ mends tliat imder these circiunstances further investi­ gations be conducted. iii. ciasses of drugs subject to certain restrictions a. alcohol hi agreement with the international sports federations and the responsible authorities, tests may b e conduct­ ed for ethanol. tlie results may lead to sanctious. b. marijuana hi agreement with the international sports federations and the responsible authorities, tests may b e conduct­ ed for cannabinoids (marijuana, dagga, hashish . . .). tlie residts may lead to sanctions. c. local anaesthetics injectable local anaesthetics are permitted under the following conditions: a) that bupivacaine, lidocaine, mepivacainc, pro­ caine etc. are used but not cocaine. vasoconstrictor agents (e.g. adrenaline) may be used in conjunction with local anaesthetics. b) only local or intra-articular injections may be administered; c) only when medically justified (i.e. the details including diagnosis, dose and route o f adminis­ tration must be submitted prior to tlie competi­ tion or immediately, if administered dining the competition, in writing to the relevant medical authority). d. corticosteroids because o f their anti-inflammatory properties, die nat lually oceiuring and synthetic corticosteroids are wide­ ly used hi medicine to treat many diseases. when administered system icallv, the)' influence tlie natural production o f corticosteroids by tlie body. corticos­ teroids may produce mood changes including euphoria and other side-eftects such that their medical use, except when administered topically, demands medical control. beeausc it was known that corticosteroids were being used non-therapeutically in certain sports by die oral, rectal, intramuscular and even the intravenous routes, die ioc medical conunission attempted to restrict dieir use dining competitions by requiring a declaration by doctors. however, as such restrictions failed to solve die problem, stronger measures, designed not to inter­ fere widi the appropriate medical use o f corticos­ teroids, became liccessary. 'hie use of corticosteroids is banned except a) for topical use (aiual, opthahnological and der matological, but not rectal; b) by inhalation; c) by intra-articidar or local injection tlie ioc has introduced mandatory reporting o f adi letes requiring corticosteroids by inhalation during competitions. any team doctor wishing to administer corticosteroids by local or intra-ar11cu lar injection, or by inhalation, to a com­ petitor must give written notification sports medicine july 1996 25 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) prior to the competition to the relevant medical authority. e. beta-bloclters due to the continued misuse o f beta-blockers in some sports tlie ioc medical commission reserves die right, at the olympic games, to test tiiose sports which it deem s appropriate. these are unlikely to include endurance events which necessitate prolonged periods o f high cardiac output and large stores o f metabolic substrates in w hich beta-blockers would severely decrease performance capacity. in agreement with tlie rules o f the internationa] sports federations, tests wall be conducted in sonic sports at tlie discretion o f tlie responsible authorities. some examples of beta-blockers are: acebutalol alprenolol atenolol labetalol metoprolol nadolol oxprenolol propranolol sotalol . . . and related substances. expanded list of examples: annex i caution: this is not an exhaustive list o f banned substances. it is provided only to give tlie reader a more com prehensive list o f baim ed substances. mail}7 substances that do not appear 011 this expanded list are considered banned under the term “ and related substances” . a. stimulants amfepramone amineptine amfetamine caffeine cathine cocaine cropropamide crotetamide ephedriue etamivan etilamfetamine etilefrine fencanifamiii fenetylline fenfluramine heptaminol medea mefenorex mephentermine mesocarb metamfetamine mcthoxyplienamine methylephedrine methylphenidate nikethamide 1 lorphenflur amine parahydroxyamfctamine pemoline phendiiuetrazine phentcmiine pli ei ly 1 eph e f i r i 11 e phenylpropanolamine pholedrine prolintane p ropy 11 lexed line pseudoephed rine salbutamol strychnine b. narcotics dcxtropropoxyphene cthyhnorpliine hydrocodone morphine pentazocine pethidine propoxyphene c. anabolic agents (1) anabolic steroids (2) betas-agonists boldenone clenbuterol clostebol danazol deliyd rocl llorniethyltestosterone dihydrotestosterone drostanolone fluoxyniesterone formebolone mesterolone metandienone metenolone metliandriol metliyltestosterone nandrolone noretliandrolone oxandrolone oxymestcrone oxymetliolone stanozolol testosterone trenbolone d. betablockers aeebutolol atenolol bctaxolol bisoprolol bunolol metoprolol oxprenolol propranolol sotalol e. diuretics acetazolamide bendroflmmethiazide bmiietanide canrenone chlortalidone furosemide liydroclilorotliiazide indapamide spironolactone triamterene f. masking agents cpitestosteronc probenecid g. peptide hormones ilcg ligh crytlu'opoietin acti-i alprenolol this information was kindly provided by the national olympic committee o f south africa q som e im portant points about ovcr-thc coimter medications and prescription drugs 1. mail}7 atiiletes purchase from their local phar­ macy over-the-counter medications for tlie treat­ ment o f e.g.headaches, sinusitis, liayfever, asthma, colds, influenza etc. 2. it is a known fact that die majority of d ie brand­ ed medications for treatment o f the above ailments contain banned substances, notably phenylpropanolamine and ephedriue. 3. an atiilete should ask liis/her pharmacist or m cdical practitioner if a medication contains any baimed substances before taking it. 4. an atiilete slioidd request liis medical practi­ tioner to complete a medical notification form whenever any drug is prescribed for treatment. 5. remember tiiat die accredited drug testing laboratory7 uses the most m odem and sensitive testing m ediods, and any atiilete taking a baimed substance will m ost certainly test positive even s o m e ' time after t aking the substance. 26 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) doping and clinical practice: ethical perspectives dr mf cusi, mb, bs, cert. s ports med. the use o f performance enhancing agents has been pre­ sent in olympic sport since the greek games, and throughout the modern olympics.' the term “doping” has been borrowed from the horse racing fraternity. the word derives from dop, a stimulant used by the kafirs in southeast africa. definitions o f doping have been based on the ability to detect forbidden substances and practices.2 34 a more philosophical definition, artificial performance enhanc­ ing, was proposed by the ioc medical commission chairman. the ioc has declared war on three accounts: a) to protect the health o f athletes b) to uphold sports ethics, which is contrary to scien­ tific manipulation c) to ensure fair competition5 the official position in australian sport is quite clear: “1. doping is forbidden. the asc condemns the use o f performance enhancing substances as both dangerous and contrary to the ethics o f sport. it recognises the need to take strong and positive action to eliminate doping. ” 8 the means to implement this policy have been to test for banned drugs and to impose heavy penalties on those found “ positive” . education has been advocated, but no clear goals and guidelines have been set. knowing athletes’ motives for drug use could also point to possible solutions. much remains unknown in this area. surveys on the extent o f doping are plagued by underreporting.78 the severe attitude that prevails at present will preclude controlled studies in future.9 the interest o f doping for a medical practitioner is threefold. 1 . knowledge o f drug intake is part o f a good medical history. 2. doctors’ attitudes bear important consequences, as athletes regard doctors as reliable sources o f infor­ mation on drugs.10 attitudes can vary from assisting athletes to use drugs, to reporting them to the rele­ vant sporting authorities, or simply ignoring the mat­ ter. 3. the extent o f doctors’ responsibility in advising and prescribing in these matters. these difficult issues will be discussed in the context o f three scenarios that medical practitioners may have to face. scenario 1. the official team doctor may the doctor o f a sports team prescribe banned sub­ stances? the answer is simple: doctors officially involved in competition sport may not ethically prescribe banned substances by virtue o f the rules that govern that par­ ticular sport. any exception to the rules must be autho­ rised by the appropriate authorities in advance. scenario 2. anabolic steroids in a non­ competitive athlete a young man wants to improve his body image lifting weights, and feels that the anabolic steroids (a.s.) will help him achieve his goal. competition rules cannot be broken because there is no competition. the doctor needs to ask four questions to decide whether it would be ethical to write a prescription for anabolic steroids. 1. are anabolic steroids effective? the scientific literature has been inconsistent and at times at odds with empirical wisdom o f the athletic community regarding the ergogenic effects o f a.s. however, the answer would have to be yes.11 2. are there any contraindications? the answer is also yes, but we need not consider this point any further in our argument. 3. are there side effects and how serious are they? the answer is again yes: there are changes in organ function, energy metabolism and also signs o f psy­ chological dependence.12 side effects should be com ­ pared to potential benefits before making a clinical decision to prescribe. 4. can we prevent, cure or alleviate a clinical condition with this prescription? the answer is a definite no. therefore the ethical response to a request o f this kind is to decline the prescription. the reaction o f the athlete can be either. a) to accept the advice and not take the a.s. b) to threaten the doctor with taking low' quality black market steroids “because they were not made avail­ able by prescription.” there are three possible cours­ es o f action open to the medical practitioner who faces this kind o f blackmail. the damage-control approach presented with a “ fait accompli” some doctors feel inclined to prescribe the desired drug, in an attempt to prevent patients from taking “ street drugs” (with no quality control), and to provide some form o f medical monitoring. maintaining contact with the patient may also give a chance to wean them o ff for good. this position is well-intentioned, but hawked for the following reasons: a) the lesser evil approach is never the right choice. if an action is considered to be wrong, this action should not be taken. b) there is no guarantee that the athlete will abide by the conditions that the prescriber may set. anecdotal experience confirms tliat atliletes easily get whatev­ er drugs they want. c) the prescribing doctor becomes a known source of steroids, and eventually a willing instrument in the spread o f their abuse: the very opposite o f the origi­ nal intention. the damage-control approach is therefore clinical ly unsound and ethically unwise. paternalistic platitudes it is easy to dismiss these athletes with paternalistic platitudes such as “ drugs are no good for you” . lack o f time or distaste for these matters are not valid reasons for dismissal, because they do not provide the athlete with an answer or a solution to his problem. counselling help in these cases requires a mixture o f firmness and gentleness in the right dose. commitment is related to the “bottom line position” . i will not prescribe a.s. gentleness refers to the counselling required: simple, logical arguments, to make the potential drug-user think twice. a conversation o f this kind may have to cover personal problems, attitudes and misconceptions that the athlete may have about him self and his social sports medicine july 1996 27 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) environment. counselling is difficult, time-consuming, and often frustrating as the final decision remains with the individual. scenario 3. a desperate decision the third scenario involves an elite female shooter. a drop in forms leads to the diagnosis o f an essential familial tremor. the treatment o f choice is propranolol, a beta-blocker banned by the ioc. she wants to perform well at her next meet to secure a long term sponsorship. this puts her in a no-win situ­ ation, and her increasing anxiety makes her condition worse. she finally makes a desperate decision: to take propranolol and give herself a chance to live normally and train as well as she can. when she talks with her family doctor, a distinction needs to be made between her actions and the actions o f the doctor. both face different ethical decisions. if she competes whilst taking beta-blockers she is in breach o f the competition rules. the prescription o f a beta-blocker in this case is good medical practice. in the absence o f contraindications it is the drug o f choice. the ethical position o f the doctor depends on the circumstances: a) if he is involved in the sport in an official capacity he cannot ethically prescribe a banned drug without official permission, as we saw in scenario 1. b) i f he is not involved in an official capacity he is not bound by those rules. thus, provided that he does not approve o f rule-breaking and says so, his pre­ scription o f the banned drug wil 1 b e ethical. the pri­ mary effect is good: the appropriate treatment o f a medical condition. there is also a bad secondary effect: the doctor will cooperate in the shooter’s breach o f competition rules i f she competes whilst on a banned drug. both effects are independent o f each other: the therapeutic effect is not the result o f the doctor’s cooperation with the breach of doping regulations. the proportion between these two effects will deter­ mine the ethical legitimacy o f the prescription. it is ethical if there is due proportion between the good intended (treatment o f a medical condition) and the secondary wrongful effect (cooperation with possible breach o f anti-doping regulations). discussion the three scenarios presented indicate that medical practice is more complex than the ioc’s anti-doping rationale admits. both the rationale and a perceived inconsistency in its application have been criticised in some quarters. a summary7 o f these criticisms would include: 1. the concept o f doping being bad per se has not been proved.13 2. the ban on drugs for the sake o f athlete’s health is derived from a paternalistic attitude that denies ath­ letes o f the principle o f autonomy. 3. i f fair competition means that all athletes can com ­ pete on equal terms, most competitions are unfair. training facilities, coaches, sports physicians and physiology laboratories are not equally available to all athletes. 4. the ban and stigma attached to drugs readily avail­ able in everyday medical practice leads athletes to the perception that they can only receive second class treatment for a variety o f illnesses. 5. the policy o f protecting athlete’s health will ring hol­ low as long as boxing continues to be a part o f olympic and commonwealth games programmes.14 all the precautions designed to protect boxers only confirm that the purpose o f boxing is to punch the opposition to defeat. as there is some merit in these criticisms, wide and frank debate o f these issues is required to provide the ioc with a sound rationale for its ethical stand on dop­ ing and for a fair implementation o f its policy. the conflicts that arise need to be addressed both by doctors and sporting authorities, as competitive ath­ letes look to their family doctor as a reliable source o f information on drugs.15 four basic points can be high­ lighted. 1. doctors who treat athletes need to be aware o f dop­ ing rules, and to be familiar with the clinical and eth­ ical issues involved in the treatment o f these patients. 2. the need to'maintain independence o f one’s medical practice. should there be a conflict o f interests, the first loyalty o f a treating physician is to the individual patient’s welfare above all other considerations.16 3. it is important to realise that the patient (athlete) must take the ultimate responsibility for his or her actions, whilst bearing in mind the weight o f a doc­ tor’s advice. 4. doping charges often carry strong emotional over­ tones, which do not help in finding solutions. a good working knowledge o f the facts clinical, historical, personal and ethical will assist greatly to think clearly, to remain objective and to make fair deci­ sions. acknowledgement this article was first published in sporthealth (volum e 13 n o 1 ) , an official publication o f the australian sports medicine federation ltd. i t is reprinted here with the kind perm ission o f the author and o f the editor o f sporthealth, d r peter brukner. references 1. h aynes s., “d oping”. a s d a update. canberra, 7 may 1991. 2. h aynes s., “d oping”. a s d a update. canberra, 7 may 1991. 3. merode a . , in “l a vanguardia” (barcelona, spain), 3 november 1991. 4. australian sports commission (a s c ). “doping p olicy”. canberra. a ugust 1990. 5. merode a ., in “l a vanguardia” (barcelona, spain), 3 november 1991. 6. australian sports commission (a s c ). “d oping p olicy”, canberra. august 1990. 7. nicholson 'a . et al. “drug use in sport. a study o f the knowledge and a ttitudes o f a section o f the australian sporting community”. a sd a , 1991. 8. martin mb and anshel mk. “attitudes o f elite australian athletes towards drug implications for effective drug preven­ tion program m es”. d epartm ent o f h um an m ovem ent science, university o f wollongong, australia. 1990. 9. frankie m and leffers d. “a th letes on anabolic-androgenic steroids”. the physician and sportsmedicine. 20, 6: 75-87. (1 9 9 2 ). 10. martin mb, a nshel mk., op. cit. 11. yessalis ce, wright je and lombardo ja. “anabolic-andro­ genic steroids: a synthesis o f existing data and recommen­ dations for future research” clinical sports medicine 1. 109 134 (1 9 8 9 ). 12. lessalis ce, wright je and lombardo ja. op. cit. 13. in stitu te o f m edical ethics. “a r eappraisa l”. london, october 1987. 14. australian medical a ssocia tion policies 4/73, 68/90, 69/90. 15. nicholson a . et al. op. cit. 16. world medicine a ssociation . international code o f ethics.^j 28 sports medicine july 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) j o u r n a l o f t h e s a s p o r t s m e d i c i n e a s s o c i a t i o n spcicts miedicinie spcrtgienieieskundis t y d s k r i f v a n di e s a s p o r t g e n e e s k u n d e v e r e n i g i n g % • spinal injuries • rugby safety rules • hypnotherapy • physiotherapy— machines v vol 3 n 0 2 1988re pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) freedom to walk, jump, run and work 5 s t e o a rts ' tis: c l i n i c a l r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) journal of the s a sports medicine association tydskrif van d ies a. sportgeneeskunde4 6 veren/o/no q editorial comment s a fe ty in rugby e | f e a t u r e h y p n o th e ra p y sasma update a n tiro o k p ro g ra m n odig e l congress s p o rt psychology congress ez3 physiotherapy column in ju ry r e h a b ilita tio n w ith m achines e9 feature spinal cord injuries in r ugby players n glansartikel 'n s ta p to g op pad na cesondheid |q ultraman big b e tte r 'b e s te r ee1 articles g uidelines f o r a u th o rs letters e d ito r in c h ie f dr c noble mb bch, fcs(sa) a ss o cia te e d ito rs proft noakes mb chb, md dr daw ie van velden m b ch b (stell), m p rax m e d (p re to ria ) a d v is o ry b o a rd medicine: d r i cohen mb chb d o b st, rcoc orthopaedic traumatology: dr p firer bsc (eng) mb bch (w its) m m e d (o rth o x w its) brig e hugo mb chb, m m e d (chir) o rth o p a e d ic s dr jc usdin mb bch, frcs (edin) cardiology: col dp myburgh sm m b chb, facc physical education: hannes botha d phil (phys ed) gynaecology: dr jack adno mb bch (w its) m d (m ed) d ip o&g (w its) front cover. transparency courtesy o f colour library. thejournalofthesa sports medicine association is e x c lu s iv e ly s p o n s o re d b y c iba-g eigy (pty) ltd. t h e jo u r n a l is p r o d u c e d b y c o m m e d ic a c c p o b ox 3 9 0 9 , r a n d b u rg 2 1 25. t h e vie w s e x p re s se d in th is p u b lic a tio n a re th o s e o f t h e a u th o r s a n d n o t n e c e s s a rily th o s e o f t h e s p o n s o rs o r p u b lis h e rs 1 4 1 6 sports injury rehabilitation programme ciba-geigy 1 _r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial commenta safety in rugby clive noble mb chb. fcs (sa) “ i afety in rugby — legal aspects and new rules rugby is a collision sp o rt. _____________ | this m eans t h a t t h e v e ry n a tu re o f th e gam e predis­ poses to in ju ry a n d s o m e tim e s s e rio u s in j u r y s ta tis tic a lly i t has b ee n sh ow n th a t s e rio u s in ju ry is fo rtu n a te ly u n c o m m o n . r e ce ntly th e re have been charges o f as­ s a u lt laid a g a in s t one p la yer by a n o th e r. w ith a g ro w in g p u b lic awareness c o n ­ c e rn in g litig a tio n , th e in te rn a tio n a l rug­ by b oard have re m in d e d responsible a u th o ritie s to see t h a t all reasonable steps be ta ke n to m in im iz e th e possibili­ t y o f b e c o m in g a d e fe n d a n t in a la w s u it by id e n tify in g and p ro m u lg a tin g "safe p ro c e d u re s" these "safe p ro ce d u re s" should includ e d th e p ro v is io n o f w r itte n m ateria l a n d th e show ing o f s a fe ty film s 2) a rra n g in g fo r a perso n a d e q u a te ly tra in e d in f irst aid to be p re s e n t a t every m atch. 3) coaches m u s t te a ch s a fe ty te c h n iq u e s in ru g b y a nd e n su re p ro p e r c o n d itio n in g ta k e sp lace fo reve rypla yer. 4) s a fe ty e q u ip m e n t s h o u ld be p re s e n t a n d in s p e c te d re g u la rly to m a k e s u re itis capable o f p ro v id in g th e fu n c tio n fo r w h ic h it is desi red. all e q u ip m e n t should be re c o n d itio n e d and replaced w h e n ap­ p ro p ria te 5) basically everyone responsi­ ble f o r su p e rvis io n o f ru g b y s h o u ld be aware o f th e m ech a nics o f th e cervical s p in e in ju rie s a n d th e d a n g e rs ig n s w hich o fte n p re ce d e ce rvical co m p lica tio n s. players s h o u ld be w a rn e d t h a t low ering th e ir heads and c h a rg in g in to an o p p o ­ n e n t, o r d iv in g in to a m au l o r ruck, can cause fr a c tu r e o r d is lo c a tio n o f th e c e r­ vical spine a n d re s u lt in q u a d rip le g ia 6 )p la y e rs s h o u ld b e o fs u ita b le b u ild a n d ade q ua te ly p re p a re d fo r th e p o s itio n fo r w h ic h th e y are selected. they sh ou ld r e p o r t any p reviou s neck in ju ry o r c o n ­ g e n ita l a b n o rm a lity . these s a fe ty p ro c e d u re s a re n o t o n ly im ­ p o r ta n t to avoid litig a tio n b u t are also fu n d a m e n ta l in th e e d u c a tio n o f any ru g ­ by team . a t th e p re s e n t sta g e in s outh a fric a , we are in so m e instances, a long way fr o m a chieving basic s a fe ty p ro c e ­ d u re s a t school level fo r example, m an v r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) i t n o t be a g o o d idea fo r th o s e boys w h o donotplay rugby,forvarious reasons,to ib e p ro p e rly tra in e d and to a ccom p an y i th e ir te a m to all gam es as one o f th e £ a m ,n c o e d u c a tio n a l schools, th e g irls m ay fill th e ro le o f f irst aiders. in m any cases, s a fe ty e q u ip m e n t is e n tire ly lack­ ing o r a t school level, is o n ly a v a ila b le fo r th e 1st and 2 n d te a m games. in som e provinces, proper c o ach in g in s a fe ty nrocedures and c o rre c t selection o f play ere is e n tire ly lacking a t t h e low er levels o f clu b ru g b y and schools ru g b y it is n o t u n c o m m o n fo r a player to be p u t in to th e f r o n t row o f th e s c ru m u n tra in e d and w ith a neck like a chicken. it m u s t be re m e m b e re d t h a t m o s t o f th e s ig n ifi­ c a n t neck inju rie s take place in th e low er levels o f rugby. rule chances for m any years, ru g b y rules were to an ex­ te n t, v a stly u n a lte re d as re ga rds s a fe ty p roce du re s fortunately, a t long last, th e in te rn a tio n a l rugby b oard (i.r.b) have woken u p to th e in h e r e n td a n g e r s o f ru g ­ by and via th e ir m edical c o m m itte e , are n ow w o rk in g to w a rd s m a k in g th is g r e a t gam esafer. new rules will beap plica b le in s outh a fric a o n ly fr o m n e x t ye a r w h ich w illim p ro v e s a fe ty a n d in c lu d e d a llta c k les above s h o u ld e r h e ig h t w ill be pe n a l­ ized. this ru le was in itia lly c h a n g e d so th a t referees co u ld d ecide f o r th e m selvesif th e y th o u g h t t h a t t h e h ig h tack­ le was d a n g e ro u s o r n o t. u n fo rtu nately, som e h o rre n d o u s h ig h tackles w e re le f t unpenalized. t h is w illb e a n e x c e lle n tru le 2 ) t o u c h ju d g e s s h a llp o in to u tfo u l play. this is an a m e n d m e n t o f a re c e n t ru le th a tto u c h ju d g e s m a y p o in to u tfo u lp la y . u n fo rtu n a te ly , m a n y to u c h ju d g e s seemed to g o b lin d ,e v e n a tp ro v in c ia la n d in te rn a tio n a l level, w h e n o b v io u s fo u l play o c c u rre d in f r o n t o f th e m . if p ro p e r­ ly applied, th is will be an e x c e lle n t ru le 3) the scrum w ill now be a lte re d so t h a t th e e n g a g e m e n t o f f r o n t rows in th e s crum will be staggered. this m eans th a t t h e f r o n t rows w ill in itia lly crouch, th e n th e y will touch th e ir o p p o n e n t. follow­ ing th is th e y will pauseand th e n th e y will engage t h is m e a n s th a tth e in itia tio n o f th e scrum w ill be m o re c o n tro lle d in­ stead o f th e p re s e n t c h a rg in g in to one a n o th e r. this o b vio u sly has m e rit, b u t w h e th e r it w ill s to p severe neck inju rie s re m a ins to be seen. in essence, w ill th is s to p collapsing o f th e scrum ? t h ere are th re e m a in fa c to rs w h ic h a re responsible f o r neck inju rie s in s e t s crum m in g a) th e s ta b ility o f th e s crum b) th e e x te n t, dura tio n a n d d ire c tio n o f th e fo r c e a c tin g on th e necks o f th e f r o n t ro w and c) th e s tr e n g th o f th e necks o f t h e f r o n t row. this n ew ru le m ay well h elp to g ive th e s c ru m m o re s ta b ility because m o re o fte n th a n n o t, th e s c ru m collapses be­ fo r e th e ball has been p u t in. s ta g ge rin g th e fo r m a tio n o fth e s c r u m m a y a ls o b e necessary. t his m eans t h e f r o n t rows w o u ld g o d o w n firs t, th e n th e locks and th e n th e lo o s e fo rw a rd s only e x p e rim e n ­ ta tio n and s c ie n tific analysis will p rovide th e answ er here. as re ga rds th e e x te n t, d u r a tio n a n d d ir e c tio n o fth e fo r c e s a c t in g o n th e necks o f t h e f r o n t row, o nly th e last n a m e d has been ta ckle d , i.e. th e hips o fth e s c r u m m e r m u s tb e lo w e r th a n h is s h o u ld e rs this w ill p re v e n t, to so m e ex­ te n t,c o lla p s e o f th e s c ru m . if th e fo rc e s a c tin g on th e neck o f th e f r o n t ro w are to o g re a t, th e n collapse will o ccurd esp ite th e s ta b ility o f th e scrum . this is m o s t likely to o c c u r in th e lo w e r level ru g b y in schools, w h e re th e necks a n d b a c k s o f th e f r o n t ro w are n o t s tro n g eno u gh . it sh ou ld th e re fo r e be co n sid e re d t h a t a t th is level o f rugby, th e fo rc e s co uld be re du ced by decreasing th e n u m b e r o f players e n g a ge d in th e s c ru m eg. a fiv e m a n scrum . we have s h o r t lin e o u ts so w h y n o t fiv e m an scru ms? as rega rds th e d u ra tio n o f th e scrum , th e lo n g e r it lasts, th e m o re d a n g e r o f co lla p se scrum s s h o u ld n o t be allowed to g o d o w n u n til th e s c ru m h a lfh a s th e b a lla n d is n e a d y fo r th e put-in. as rega rds neck s tre n g th , all p la y e rs ,fro m th e m o s tju n io r, s h o u ld be g ive n exercises f o r neck and back s tr e n g th n o m a t te r w h a t p o s itio n th e y p la y .4 )w h e e lin g o fth e s c ru m w illo n ly a l io w a 9 0° tu rn . itis u n c e rta in w h e th e r th is w ill have a s ig n ific a n t e ffe c t o n s a fe ty in th e scrum . t he fo rc e d w h e el ie. w h e re th e o ne f r o n t ro w stops p ush in g and moves rapidly backwards, is d angerousin t h a t itm a k e s th e s c ru m unstablethesig n ific a n c e o f w h e e lin g o f th e s c ru m will s till have to be fu lly e lucidated. 5) players e n te rin g th e loose scrum m u s t have th e ir s h o u ld e rs h ig h e rth a n th e irh ip s t h is is a g o o d ru le in p re v e n tin g excessive fle x io n fo rc e to th e n e c k b u titw illb e e x t r e m e ly d if f ic u lt to a p p ly it. w ith th e changes i have m e n tio n e d above, it appears t h a t g o o d prog ress is b eing m ad e in s a fe ty in rugby. june 1988vol 3, no 2,1988 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) _ feature destructi behaviour patterns dr c trevor modlin mb, bch. (w ftwatersrand) — anagem ent o f de­ structive behaviour patterns in a sports­ man by hypnothe rapy 1 the problem a t th e t im e o f th is c a s e s tu d y , m rx wasa 28 y e a ro ld hockey p la yer his a b ility was n e v e r in q u e s tio n — he played a t senior m ter-provincia i level and as fa r as his skills, fitn e s s , m o t iv a t i o n a n a ta c t ic a l know ledge o f th e gam e were concerned he was n o t lacking — indeed, he had fe w p eers h ow ever he had n e v e r achieved th e u lrim a te a c c o la d e o fa s p rin g b o k c a p h e is m te llig e n ta n d h a s fu llin s ig h tto th e e x te n trh a th e subjected h im s e lf to a b ru ­ ta lly h o n e s t self-appraisal and ca m e to th e c o n c lu s io n th a t w h a ^ h e ld h im back fr o m fu ll re c o g n itio n was his lack o f e m o ­ tio n a l c o n tro l on th e fie ld he a d m itte d th a t a n e r r o r b y him self, a te am -m ate. o r a n e rro rb y a n u m p ire u pse t h im s o m u c h th a t d e sp ite his u n d e rs ta n d in g b e fo re and a fte r th e game, he lo s t c o n tro l w hile o n th e fie ld he b ecam e fr u s tr a te d and a n g ry and th is aggression was d e s tru c ­ tiv e to his o w n game, th e te a m e f f o r t and in v ite d sh arp re a c tio n fr o m u m p ire s as p rofessor p o tg ie te r has p c in te a o ut, m r x placed u n re aso n ab le d e m a n a s on h im s e lf fo r p e rfe c tio n t h is d e m a n d ex­ tended to h is te a m m a te s a n d th e p e rfo r m a n ce o f th e u m p ire s h is subcon­ scious resoonse (fo r he was fu lly aware a fte r th e fa c t b u t unable to m ain ta in self c o n tro l in th e h e a t o f th e m o m e n t' was aggression w h ic h once displayed te n de d to escalate w ith th e n e x t in c id e n t 2. discussion with mr x we e x p lo re d d if fe r e n t ways o f h a n d lin g his p ro b le m — even to th e m a tte r o f ac­ ce p ta n ce o f his a lre ad y s ig n ific a n t a c h ie v e m e n ts and t h a t a s p rin gb o k cap m ig n t be beyond hi m a t th e age o f 28 his m o tiv a tio n h eld sway — he d ea rly want e o a ia s t o p p o r tu n ity h y p n o s is w a s th e n discussed as a m eans o f tre a tm e n t, in p a rtic u la r th e n a tu re o f hypnosis, his e xpe cta tion s and th a t o f m y ow n a course o f th re e o n e h ou rsessions june 1988 vol 3. nc 2 1988 was agreed to w ith an opportunity to th e n review p rogress 3. the first session such was his m o tiv a tio n t h a t hypnosis was ind u ce d w ith lit t le d if fic u lty using eye fix a tio n the level o f tra n c e was deep­ en ed by a reve rse a rm le v ita tio n and fu r th e r d ee p en e d by a reverse c o u n td o w n a t th is s ta g e he was in a m e d iu m tra n c e and i th e n p roceeded w ith hartland's ego r e in fo rc e m e n t p a tte r he was th e n asked w h e th e r o r n o t ms subconscious m in d fe lt h e c o u ld a lte r his im p u lsive b e h a v io u r on th e fie ld o f play his a u to -m o to r response b e in g a ffir m a ­ tive, d ire c t su gg e stio n s w e re th e n m ade t h a t m th e e v e n t o f an in c id e n t t h a t w o u ld p reviou sly have re su lte d in loss o f c o n tro l, hissu bco n scio usm ind w ould im ­ m e d ia te ly be a le rte d to th a t fa c t and r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a u to m a tic a lly a c t w ith m a x im u m c o n ­ tr o l it was suggested t h a t th is c h o ic e o f p o s itiv e c o n tro l w o u ld re su lt in a fe e lin g o f g re a t p ow er and c o n fid e n c e protec tiv e su g g e s tio n s w e re th e n m a d e as re ­ gards non-clinical h y p n o s is and he was give n a f u r t h e r suggestion to allow ra pid in­ d u c tio n f o r t h e n e x t session. he was th e n ta u g h t to 'wake' h im s e lf u p 4. the second session the p a tie n t re p o rte d a fe e lin g o f w e ll­ b eing since t h e last session. hypnosis was ra p id ly in d u ce d and in te n ­ s ifie d to a d e e p level. this session was larg ely r e p e titiv e e x c e p tth a t i t wasalso su gg e sted t h a t n o t o n ly w o u ld his sub­ conscious m in d respond favourably, b u t t h a t each s u b s e q u e n t in c id e n t w o u ld f u r t h e r re in fo rc e th is p o s itiv e response n o t o n ly a ta n e m o tio n a l level b u ta ls o a t th e le v e lo fh is s k ills a n d h is e n jo y m e n to f th e game. using im agery, he was asked to re m e m b e r a g a m e in w h ic h h e h a d re s p o n d e d in th e old' fa sh io n to s tre s s he was asked to replay s p ecific incidents w ith his n ew ca p a b ilitie s and re p o rte d t h a t he coped c o m fo rta b ly w ith o u ta g g re s s io n . a t th is tim e a n d w ith his a g re e m e n t, a te c h n iq u e fo rs e lf-h y p n o s is was suggest­ ed, he was awoken and re q u e s te d to in­ d uce self-hypnosis. this he achieved a d m ira b ly and he was g ive n a ta p e to use u n d e r self-hypnosis on a daily basis 5.thethird session m rx re p o rte d t h a t th e league g a m e he had played since th e last ses­ sion w a s 'fa n ta s tic and th a tte a m -m a te s a n d o p p o s itio n m e m b e rs had c o m m e n te d on his p e r fo rm a n c e this had d o u b ly e n c o u ra g e d h im t h a t he was m akin g p ro g re s s this session was once m o re a re p e a t w ith th e a d d itio n o f im a g e ry t o im p ro v e his skills and his 'vision' on th e field. im agery wasalso used to visualise a n d fe e lth e s e n s a tio n o fw in n in g and th e c o n fid e n c e t h a t resulted. hewas encouraged to in d u ce se lf­ hypnosis, if o n ly fo r a fe w '8 8 vol 5, no 2. 19s8 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m inutes, p r io r to a g a m e and c o n c e n ­ t r a t e o n e g o r e in f o r c e m e n t a n d c o n fid e n c e 6. top-up session 36 h o u rs b e fo re he was d u e to leave fo r th e inter-p rovincial t o u rn a m e n t, he d e ­ v e lo pe d a g ro in s tra in d u rin g a tra in in g session. t h isw asasevere b lo w to h is c o n fid en ce. this session th e re fo r e c o n c e n ­ tr a te d on a te c h n iq u e o f pain c o n tro l w hich h e co u ld apply underself-hypnosis he was am azed to fin d t h a t he co u ld in fa c t achieve th is co m p letely. n e v e rth e ­ less, he was w a rn ed to use th is o n ly fo r th e d u ra tio n o f each g am e and he was p re s c rib e d an a n ti-in fla m m a to ry a g e n t and re fe rre d f o r p h y s io th e ra p y p r io r to h im leaving f o r th e to u rn a m e n t. 7. results i was roused fr o m sle e p a t 1,30am sixdays la te rb y th e te le p h o n e . a v e ry h appy and obviously in e b ria te d m r x w a s o n th e lin e h e h a d p la y e d a b lin d e ro f a to u rn a m e n t and... had been selected fo r th e 'bok' squad. it was one occasion i d id n 't m in d being w oken up by a d ru n k e n p h o n e call! 8. observations w hile th is case s tu d y w o rk e d to p e rfe c ­ tio n , th e re are m a n y p itfa lls in th e a p p li­ c a tio n o f h y p n o th e ra p y in sp o rt. points to consider: 1. it is im p o r ta n t t h a t th e th e ra p is t is au fa it w ith th e s p o r t f o r m a x im u m advantage. 2. it is im p o r ta n t t h a t a re alistic discus­ sion ta k e p la c e p r io r to h y p n o th e ra p y : to o m an y s p o rts p e o p le e x p e c ta mira c le o fm u m b o ju m b o th a tw ill rem o ve all th e irp ro b le m a re a s a n d m ake th e m kings. 3. it m u st n o t d e tra c t fr o m th e necessa ry d e d ica tio n . 4. it is im p o rta n t, if o n e is to help and n o t be d e s tru c tiv e , t h a t h y p n o th e ra p y is u n d e rta k e n in c o n s u lta tio n w ith th e coach — especially in th e area o f skills 5. the m ain s tr e n g th o f h y p n o th e ra p y , i feel, is in t h e area o f b u ild in g c o n fi­ dence. n o t in an a rro g a n t fashion, b u t w ith q u ie t and sure in n e r s tre n g th w h ic h w ill allow th e s p o rts p e rs o n to p e r fo r m a t an o p tim a l level. ^ bibliography p r o f j p o tg ie te r — 'r a s io n e e l-e m o tie w e te r a p ie v irs p o r tlu i.' — j. o f sa s p o r ts m e d ic in e assoc. vol 2 n o 4 june 1988 vol 3, no 2,1988 6r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a sasma r antirook program nodig! t he m ain o b je c ts o f th e s outh a frican s ports m edi­ cine a ssocia tion are th e a d v a n c e m e n t o f t h e science and a r t o f s p o rts m edicine, a nd to fo ste r, p ro m o te , s u p p o rt, a u g ­ m e n t, develop and e nco u ra g e investiga­ tiv e k n o w le d g e o f sp orts m edicineand its ra m ific a tio n s . t h e s p o rts m e d ic in e jo u r nal p rovides an ideal fo r u m to publish o rig in a l research a rticle s in s p o rts m e d i­ cine and to d is s e m in a te k n o w le d g e in th e fie ld o f h e a lth p r o m o tio n th r o u g h e x e r cise a nd a h e a lth y lifestyle. w eare p ro u d to ackno w le dg e t h a t m o re and m o re o rig in a l re s e a rc h a rtic le s a re o ffe re d fo r p u b lic a tio n in th is jo u rn a l. it is o f p a rtic ­ u la r s ign ifica n ce to ta ke n o te o f th e fa c t t h a t th is jo u m a lq u a lifie s fo rs u b s id ie s fo r research o u t p u t fo r u n iv e rs itie s as o u t­ lined in th e nasop 02-014 (87/7) re p o rt. this will m o tiv a te academ ics in s outh a fric a to pub lish th e irre s e a rc h fin d in g s in th e s p orts m edicine j o u rn a l to th e m u tu a l b e n e fit o f all o u rm e m b e rs in th e m edical and para-m edical fie ld c o n ­ cerned w ith th e practice and a d m inistra ­ tio n o f s p o rt in o u r c o u n tr y we w o u ld like to keep o u r a rtic le s as s h o r t a n d in fo r ­ m a t iv e as possible, and a im e d a t th e general p ra c titio n e r involved in th e to ta l c a re o fth e a th le te t h e re g u la rc o n trib u tio n s o n n u tr itio n and p h y s io th e ra p y in o u r jo u rn a l f u lfil a g re a t need on m o re s c ie n tific in fo rm a tio n and co -o p era tion w ith th e s e re sp e ctive fie ld s o f in te r e s t d ies portgeneeskundev erenigingbeyw e r h o m ook v ir die b e v o rd e rin g van g e s o n d h e id d e u r d ie a a n le e r van gesonde lew ensgew oontes, en w il h om graag a m p te lik skaar by d ie instansies soosb yvoo rbe e ld d ie s a mediese navor singsraad, die nasionale k ankerverenig ing en die nasionale raad v ir rook en gesondheid in suid-af rika, asook die hart stigting d e u r die p ub lie k bew us te m aak van d ie g e s o n d h e id s g e v a re w a td ie ro o k g e w o o n te inhou. s p o rtlu i is n ie a lty d be­ wus van die o n m id d e llik e n adelige ef fekte w a t die rook van s ig a re tte h e t op june 1988 vol 3, no 2,1988 h u lle s p o rtp re s ta s ie s nie. soveel as 16% van die to ta le h e m o g lo b ie n van 'n s tra w w e ro ke r kan v e rb in d wees m e t ko olstofm onoksied van sigaretrook, en is dus nie beskikba a r v ir die tr a n s p o r t van s u u r s t o f n ie . die a f f i n i t e i t v a n hem o glo bie n v ir koolstofm onoksied is ± 250 m e e r as die v ir s u u rs to f en die ka rb o k s ie h e m o g lo b ie n vla k ke keer eers 4 8 u u rn a d ie s ta a k v a n r o o k te r u g n a d ie van nie-rokers. d iechroniese hipoksem ie van die roker, veroorsaak 'n polisitem iese respons w a t beteken d a t rook 'n stim ulu s is to te ri-tro p o i'e s e . 'n v erdere k o m p lis e re n d e fa k to r v ir die s p o rtm a n is d a t k o o ls to fm o n o k s ie d die s u ursto fd isso siasieku rw e na links ver s k u if w a t ve ro o rsaa k d a t m in d e r s u u r­ s to f beskikbaar is vird ie p e rife re w e e fse ls as gevolg van d ie g ro te r a ffin ite it va n d ie h e e m v irs u u rs to fb in d in g .a i bogenoem de fa k to re h e t 'n n adelige e ffe k o p aer obiese m e ta b o lis m e en sal s p o rtp re s ta ­ sies d ie n o o r e e n k o m s tig n a d e lig bei'nvloed.1 s u id -a frik a b e n o d ig 'n o m v a tte n d e a n ti ro o k p ro g ra m w a ts a l v o o rk o m d a tjo n g m ense begin rook, die re g te van nie ro kers sal b eske rm en ro ke rs w a t graag w ilo p h o u .s a lb y s ta a n .2 in d ie lig van d ie f e it d a t ro o k die fisieke w e rk v e rm o e van s p o rtl ui n e g a tie f bein vloe d,aso o kdie ge son d he idsb en a de lin g w a t passiewe ro ok v ira lle p e rs o n e inhou, h e t d it m iskien ty d g ew ord d a t ro o k by a lle sp o rtb y e e n k o m s te ,b y n a m e b in n e n shuise b y ee n ko m ste by wyse van wet g ew in g verb ie d word. die wereldgesond heidsorganisasie h e t 7 a p ril 1988 as die w ereld rook verbode dag v e rk la a r— d it is 'n g u id e g e le e n th e id v ir die suid a frika a n se s p o rtg e n e e s k u n d e vereni g in g o m h o m te s k a a rb y d ie p o g in g s v a n d ie in te r n a s io n a le g e s o n d h e id s o r g a n is a s ie o m d ie g e s o n d h e id e n le w e n s k w a lite ite van al die lede van ons bevolk in g te v e r b e te r! 1. j m o o re -g illio n , t c pearson. s m o k in g a n d p o ly c y th a e m ia . b m j 1 9 8 6 ,2 9 2 :1 6 1 7 -1 6 1 8 . 2 .g s t o w n sh e n d ,d y a c h .a n ti-sm o kin g le g isla tio n a n in te rn a tio n a l p e rs p e c tiv e a p p lie d to s o u th a fric a . s a m j 1 9 8 8 ,7 3 :4 1 2 -4 1 6 . 7r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sport psychology congress eporton the parti­ cipation in the ivth international con­ gress of sport psychology t h e iv th in te r n a tio n a l congress o f s p o rt psycho-^ logy, orga nise d by th e a ssociation p o u r la recherche en psychologie du s port, to o k place a t th e u n iversite libre de b rux­ elles, 3-6 n o v e m b e r 1987. a p p ro x im a te ly 100 dele­ gates re p re s e n tin g 29 c o u n trie s a tte n d e d th e fo u r day p ro ­ g ram m e. it was th e aim o f th e congress to p ro v id e researchers w ith a fo r u m to p re s e n t th e ir la te s t research fin d in g s and s ti­ m u la te discussion on f u tu r e d e ­ v e lo p m e n ts and tre n d s in s p o rt psychological research and practice. the c o n ­ gress fo c u se d on th r e e m ain areas o f co n c e rn to s p o r t psychologists: (1) stress and a n x i­ e ty; (2) p sych o lo g i­ cal aspects o f suc­ cess and failure; and (3) m o to r learning, p e rc e p ­ tio n and decision m akin g in th e s p o rtin g arena. all in all 40 papers w e re read, 40 p o s te r sessions held, and 2 ro u n d ta b le e vening dis­ cussions convened. the ro un d tableeveningdiscussionscon vened by tw o o f th e m o s t o u ts ta n d in g a m e ric a n s p o r t psychologists, p r o f b.c. o g ilvie a n d prof. r. n ie de ffer, p ro v id e d th e h ig h lig h ts o f th e congress. delegates m ade goo d use o f th e rare l o p p o r tu n ity to d raw on th e rich e xpe rie n ce and deep in s ig h t o f th e tw o prese n ­ ters. it becam e a p p a re n t how y o u n g a fie ld o f research and a p p lic a tio n s p o r t psych o lo g y s till is and th e im m e n s e scope fo r f u tu r e d e v e lo p ­ m e n t. the m o s t im p o r ta n t p o in ts e m e r­ g in g fr o m th e discussions were: (1) the psychological h e a lth and well-being o f th e a th le te o r s p o r t p a r tic ip a n t is o f p rim e co n c e rn to th e s p o rt psychologist. this c o n ­ c e rn m ig h t well place th e p s ych o lo g ist a t odd s w ith th o s e o f s p o r t p ro m o te rs and m a n a g e m e n t. (2) a th le te s and s p o rt p a rtic ip a n ts d o n o t a p p ro a ch psycholo­ gists toseek 'th era p y': a thletes and s p o rt p a rtic ip a n ts are in te re s te d in psycholo­ gists p ro v id in g th e m w ith s p ecific skills, like re la x a tio n te c h n iq u e s to cope w ith c o m p e titio n stress and /or c o g n itiv e s tru c tu re s to m a in ­ ta in h ig h m o tiv a tio n levels. (3) psychologists o p e ra tin g in th e s p o rtin g arena sh ou ld n o t d e lu d e th e m s e lv e s a b o u t fin a n c ia lg a in .t h e p ro v is io n o f s p o rt psy­ chological services can o nly beseen asan a d d itio n a l avenue o f p rofe ssion a l prac­ tice, n o t th e m ain o r o n ly area o f p ra c tic e the p a p e r p re s e n t­ ed by th e d elegate fr o m s outh africa, dr. h elgos chom er, uctdept. o f psychol­ ogy, e n title d "cogni­ tiv e s tra te g ie s and th e p e rc e p tio n o f tra in in g e ffo r t o f m a ra th o n runners" was v e ry well received, g e n e ra tin g lively de­ b ate w ith th e s tro n g re c o m m e n d a tio n t h a t th e research in to c o g n itiv e s tra ­ tegies th r o u g h o n -th e s p o t re c o rd in g be e x te n d e d to o th e r e n d u ra n ce s p o rts so th a t m o re possible cog n itiv e tr a in ­ ing p ro g ra m ­ m es be generated. t h ere were no signs o f any n a tu re t h a t th e presence and p a rtic ­ ip a tio n o f a d ele ga te fr o m s outh a fric a p re s e n te d any p o litic a l (or o th e rw is e ) concern. the fin a n c ia l assis­ ta n c e g ra n te d by thehsrc fo r th e p a rtic ip a tio n in th e congress is g ra te ­ fu lly acknowledged. j june 1 9 8 8 vol 3 ,n 0 2 ,1 9 8 freprod uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the wraps are off! s m i t h + n e p h e w healing in mdur hands s m ith a n d n e p h e w l t d ., 30 g illitts r o a d , p in e to w n 3610. how elastoplast*poroos elastic adhesive bandage gives controlled compression and flexible support w h e n t r e a t m e n t d e m a n d s a b a n d a g e t h a t gives c o m p r e s s i o n a n d f le x i b le s u p p o r t , y o u r f irs t c h o i c e m u s t b e e l a s t o p l a s t p o r o u s e l a s t i c a d h e s i v e b a n d a g e . t h e s e c r e t o f t h e e f f e c t i v e n e s s o f e l a s t o p l a s t p o r o u s e la s tic a d h e s i v e b a n d a g e lies in its e x c e p t i o n a l l e n g t h w a y s s t r e t c h a n d r e g a i n p r o p e r t i e s w h ic h e n a b l e it to b e a p p l i e d w it h t h e c o r r e c t t e n s i o n t o giv e c o n t r o l l e d c o m p r e s s i o n . t h e s e s a m e s t r e t c h a n d r e g a i n p r o p e r t i e s g ive fle x ib le s u p p o r t a l l o w i n g p a t i e n t m o b i l i t y a n d full p a r t i c i p a t i o n in r e h a b i l i t a t i o n p r o g r a m m e s . d e v e l o p e d f o r s o u t h a f r i c a n c o n d i t i o n s , e l a s t o p l a s t p o r o u s e l a s t i c a d h e s i v e b a n d a g e is id eal fo r s t r a p p i n g s w o ll e n o r s p r a i n e d j o i n t s , v a r i c o u s v e i n s , leg u lc e r s a n d f o r o t h e r s u r g ic a l a n d o r t h o p a e d i c p u r p o s e s . t h e s o f t fluffy e d g e s o f t h e b a n d a g e h e l p to a v o i d c u t t i n g a n d m a r k i n g th e s k in . a n d a l t h o u g h a d h e s i v e , t h e b a n d a g e is p o r o u s , a l l o w i n g t h e s k in to b r e a t h e a n d s w e a t a n d e x u d a t e t o e s c a p e . it is f e a t u r e s like t h e s e , c o u p l e d , w ith b a c k u p s e r v ic e a n d s t r a p p i n g t e c h n i q u e t r a i n i n g p r o g r a m m e s t h a t h a v e m a d e e l a s t o p l a s t p o r o u s e l a s t i c a d h e s i v e b a n d a g e y o u r first c h o i c e f o r t h e p a s t 5 0 y e a r s . n o w t h e w r a p s a r e o f f, a s k f o r it b y n a m e w h e n y o u n e e d c o n t r o l l e d c o m p r e s s i o n a n d s u p p o r t . * r e g i s t e r e d t r a d e m a r k 2 2 1 4 4 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) injury rehabilitation with machines m csiffm sc, phd c om m unication studies division, university o f th e w itw atersrand june 1988 vol 3, no 2,198* 10 o n s id e ra b le re lia n c e is p la c e d o n m achine-based re h a b ilita tio n by p h y s io ­ th e ra p is ts o r t h e ir c o l­ leagues in g ym n a sia . a p h y s io th e ra p y p ra c tic e is o fte n re g a rd e d as c o m p p le te o n ly i f th e la te s t c o m p u te r c o n tro lle d is o k in e tic d e v ic e isavailable. a g y m n a s iu m is view ed as p r im itiv e u n ­ less it c o n ta in s c o m p lic a te d , c h ro m e p la te d , v a ria b le re sista n ce m a c h in e s o r m u lti-p u rp o s e s ta tio n s . c lie n ts are im p re sse d , business flo u ris h e s and th e r e seem s lit t le need to c ritic iz e th e s y s te m .t h e q u e s tio n o f s c ie n tif­ ic a lly e v a lu a tin g th e s e devices, how ever, s till rem ains. to a n sw e r th is q u e s tio n , i t is neces­ sa ry to r e m e m b e r t h a t th e a im o f m usculoskeletal re h a b ilita tio n in p ar­ tic u la r is r e s t o r a tio n o f f u lls tr u c tu r al a n d f u n c t io n a l s t a b ilit y a n d m o b ility to th e p a tie n t. in s p o rts m e d ic in e th is e n ta ils p re p a rin g th e a th le te to re g a in th e s tr e n g th , e n ­ durance, fle x ib ility , speed and a g ility q u a litie s s p e c ific to th e s p o r t he o r she plays. in th is re sp e ct, m a ch in e s a re o fte n p re s u m e d to be s a fe r and m o re e ffe c tiv e th a n a n y o th e rc o n d i tio n in g m o d a litie s , d e s p ite th e fa c t t h a t no w e ll-c o n tro lle d s tu d ie s have y e t s h o w n is o k in e tic o r o t h e r m achines to be s ig n ific a n tly s u p e rio r to th e tr a d itio n a l p h y s io th e ra p y m e th o d s u s in g p n f fp ro p rio c e p tiv e n e u ro m u s c u la rfa c ilita tio n ) o r w est­ m in s te r pulleys. why machines? m achines w e re d e v e lo p e d to c a te r f o r th e lu c ra tiv e usa b o d y b u ild in g m a rk e t, w ith t h e ir a p p lic a tio n in p h y s io th e ra p y fo llo w in g later. one machine, th e is o k in e tic 'c y b e x 'e m e rg e d b o th as a s tr e n g th o r to r q u e te s tin g device and as a re h a b ilita tio n m achine. all m a ch in e s have been c o m p a re d w ith fr e e w e ig h ts by t h e ir m a n u fa c tu re r s and p ro n o u n c e d to b e s a fe r.m o re s p a c e and tim e e ffic ie n t, and m o re e ffe c tiv e in e n h a n c in g s tre n g th . som e m achines, such as cy bex, n a u tilu s and universal w e re d e s ig n e d to va ry th e re sista n ce t h r o u g h o u t th e ra n g e o f m o v e m e n t, s in c e th e fo rc e w h ich can be e xerte d by any m u s c le g ro u p v a rie s w ith jo in t a n g le a n d m e c h a n ic a l leverages. t h is fe a tu re w a s c la im e d to m ake v a ria ­ b le o r a c c o m m o d a tin g re s is ta n c e m achines s u p e rio rto fre e w eights, since " th e re sista n ce o ffe r e d by w e ig h ts re ­ m ains c o n s ta n t t h r o u g h o u t th e ra nge o f any m o v e m e n t". machines and physics a c c o rd in g to n ew ton's s econd law o f m otio n , co nsta n cy o f fo r c e o r resistance is im p o s s ib le f o r any load w h ic h is ac­ c e le ra te d f r o m re s t and d e c e le ra te d back to re st again. m oreover, fo rc e p la te analysis by th e a u t h o r has sh o w n t h a t th e tr a in e e r e g u la r ly a n d q u ite u n c o n s c io u s ly a lte rs th e a c c e le ra tio n o f a fr e e w e ig h t, th e re b y a u to m a tic a lly p ro d u c ­ ing a c c o m m o d a tin g resistance. this ty p e o f a c c o m m o d a tio n isphysiological ly m o re d e s ira b le th a n th e p re d e te r­ m in e d v a ria tio n s im p o s e d by n a u tilu s a nd universal in p a rtic u la r, as it is m e d i­ a te d via th e n e u ro m u s c u la r a p p a ra tu s o f th e ind ivid ua l. iso kin e tic devices such as cybex, k inco m and m in ig ym are also s u p e rio r in th is re g a rd , since th e ir resistance issim ila rly d e te rm in e d by th e response o f t h e tra in e e isokinetic machines iso kin e tic m achines, th o u g h th e y ap­ p e a r to be s ta te o f th e a r t to phys­ io th e ra p is ts , a ls o s u f fe r fr o m m a jo r lim ita tio n s . firstly, is o k in e tic c o n tra c tio n rarely, ife ver.isa n a tu ra l m o d e o f o p e ra tio n fo r h u m a n m usclesandex tra p o la tio n o f is o k in e tic te s ts to con c e n tr ic a n d e c c e n tr ic c o n tr a c tio n is o f d u b io u s v a lid ity . p ro b a b ly m o re s e r io u s is th e f a c t th a t th e r e is a tim e lag b e tw e e n in itia tio n o f m o v e m e n t and re sis ta n c e p ro d u c e d by th e m achine. f u rth e rm o re , te r m in a tio n o f each m o v e m e n t on an is o k in e tic m a c h in e d o e s n o ts im u la te th e s a m e n e u r o m u s c u la r r e fle x p a t te r n s w h ic h o c c u r in fr e e m o v e m e n t o r m o v e m e n t a g a in s t w e ig h ts o r pulleys. is o k in e tic m a c h in e s also disp la y m a jo rm e c h a n ic a l d eficiencies. anal y s is b y th e a u th o ra n d o th e rw o rk e r s reveals t h a t t h e cybex, f o r instance, is a t no speed e n tir e ly is o k in e tic , a d e fe c t w h ic h b e c o m e s p a rtic u la rly s e rio u s a th ig h e r s p e e d s t h e p r o p r i o c e p ti ve c o n tro l e v e n ts e lic ite d u n ­ d e r th e s e c o n d it io n s d i f f e r d ra m a tic a lly fr o m th o s e o c c u rrin g in fre e m o v e m e n t,s o it is a d v is a b le th a t is o k in e tic tr a in in g fo r m a v e ry lim i­ te d p a r t o f th e r e h a b ilita tio n process. in a d d itio n , m o s t is o k in e tic m a ch in e s do n o t o ffe rth r e e d im e n s io n a l m o tio n o r sequential c o n c e n tric -e c c e n tric m uscle c o n tra c tio n . finally, n o n e o f th e m y e t is a ble to o p e ra te a t t h e v e ry h ig h speeds associated w ith th e im p u ls iv e changes in d ire c tio n p ro d u c e d in m o s ts p o rts . in o th e r w ords, is o k in e tic m a ch in e s m ay r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) play a ro le in re h a b ilita t­ ing c o n tra c tile m uscle tissue, b u t are se rio u s ly lim ite d in c o n d itio n in g so ft tissues w h ic h s to re a n d re le a s e e la s tic e n e rgy. iso kin e tic m a ch in e s w e re in n o v a tiv e o v e r 15 years ago; th e k incom a n d s im ila r m a c h in e s have rem oved som e lim i­ ta tio n s , b u t th o s e c o n ­ te m p la tin g th e purchase o f isokine tic m achines should w a it fo rth e c h e a per,m oreadvanced m ac­ h in e s w h ic h m o d e r n c o m p u te r te c h n o lo g y w ill no d o u b t p ro d u c e in th e n e a r fu tu r e . machines in general it has a lr e a d y b e e n shown th a t accom moda tin g o r va riable resist­ ance occurs w h e th e r c w eights, pulleys o r special m achines claim ed to o f f e r th is exclusive fe a tu re . one a d va n ta g e is p ro v id e d by fre e w e ig h ts and pulleys, n a m e ly t h a t each tra in e e can va ry th e resistance according to his s p ecific n eeds t h e c a m s o rle v e rs o fm a c h in e s a r e b u iltto s u itth e a v e r a g e person (w hatever th a t m ig h t be) and can­ n o t be a lte re d f o r t h e individual. the m ajor advantages and disadvantages of m a c h ine slie in th e f a c t t h a t m achines isolate a lim ited n u m b e ro f muscle groups in a specific plane o f o pe ra tio n . if co n d i­ tio n in g o f a p a rtic u la r inju re d m uscle is desired in one d ire ction , th e n m achines can be useful. however, vo lu n ta ry m uscle a ction involves concentric, e ccen tric and isom etric c o n tra c tio n allied w ith p ro p rio ­ ce p tive c o n tro l over several degrees o f th re e d im e n s io n a l fre e d o m , co n d itio n s w hich no m achines caneven vaguely p ro ­ v id e in particular, m achines im pose little dem and on th e balanceand co ord in a tion m echanism s necessary fo r all sp orts m ovem ents, so th a t m achine re ha bilita ­ tio n shouid f u m ish o n ly a iim ite d p a rt o f th e sp ectru m o f c o n d itio n in g m odalities this m eans t h a t ade q ua te re h a b ilita tio n ca n n o t be achieved by m eans o f simple, m o n o p la n a rf lexion-extension on cybex, universal o rn a u tilu s machines, fo rexa m pte r eturn to fu ll s tru c tu ra l and fu n c tio n ­ al s ta b ility and m o b ility necessitates flexion-extension, a d d u c tio n -a b d u ctio n and ro ta tio n a l co n d itio n in g : in o th e r words app lica tion o f th e pnf p rinciple tnat prescribes spiral/diagonal p a tte rn s augmented by r e c r u itm e n to f th e neces­ sary stre tc h reflexes pnf, fre e w eights ana pulley systemscan achieve this* b u t no m achines can, despite th e g re a t co s t o f th e latter, machines and safety jt i s o f t e n presu m ed th a t m achines are saterthan fre e weights, d esp ite th e fa c t june 1988 vol 3, no 2,1988 thisclaim . certainly, m achinescan besafer fo r a person w hose balancing o r p ro p ri­ o cep tive capabilities are seriously im ­ paired, b u t th e p h y s io th e ra p is t w ould hard ly prescribe w e ig h ts o re v e n d y n a m ­ ic m o v e m e n ts w h e n is o m e tric s o r fara dism m ig h t be th e p re fe rre d p rim a ry tre a tm e n t. obviously, one m u s t be fam i lia rw ith th e m e rits a n d deficiencies o f all tr e a tm e n t modalities. some m achines are p o te n tia lly m o re h a rm fu l th a n th e e q u iva le n t w e igh ts o r pulley exercise for instance, m o s t bench press, seated-press, 'pec-deck; seated leg press and leg extension m achines con­ strain one to co m m e nce m o v e m e n t near th e w eakest biom echanical p osition fo r th e re le van t joints. m oreover, these m achines usually d o n o t a llo w o n e to p re s tre tc h th e muscles o r p ro v id e a reserve o f elastic energy in th e collagenous tissue f o r t h e initial acceleration phase force on s tru c tu re s o f th e lu m b a r spine is usually g re a te r w h e n using th e seated press and back-extension m achines as com pared w ith th e free-weights standing press and d e a d lift respectively. machine leg-curls d on e p ron e on f la t benches can hype rexten d and dam age th e lu m b e r spine, w h ile f ull-range m achine leg-presses can cause h yperflexion in ju ry to th e s a m e region. num erous machines pose sim ilar hazards to th e body, so i t is essential fo r th e phy­ siotherapist, b io k in e tic is to rg y m in s tru c ­ t o r to th o r o u g h ly u n d e rs ta n d th e kinesiological p a tte rn s im posed by any m achines w h ich m ig h t be used fo r re­ h a b ilita tio n o r n o rm a l tra in in g . machines and efficiency machines can be very e ffic ie n t in tra in in g isolated m uscle groups, b u t h ig h ly in e ffi­ c ie n t in co n d itio n in g th e b o d y in te r m s o f th e n u m b e ro f machines required to o ffe r ade q ua te c o n d itio n in g o f even a single jo in t. despite th e adver­ tisin g claim s o f m a n u fa c ­ turers, it requires a fa r g r e a te r v a r ie t y o f m a c h in e s th a n fr e e w e igh ts to achieve th e same th ree-dim ensional tra in in g e ffe c t on th e s o f t tis s u e s , n e u r o ­ m uscu lar system s and p r o p r io c e p tiv e m e c h ­ anisms o f th e body. obvi o usly, t h is is m o s t b e n e fic ia l t o t h e m a n u fa c tu re r, and n o t th e p a tie n t. conclusion this a rtic le was n o t in­ te n d e d t o o f f e r a th o ro u g h analysis o f th e very extensive fie ld o f m achine re ha bilitatio n: instead its purpose was to a c q u a in t th e re h a b ili­ ta tio n professional w ith th e scopeand lim itations o f p opulartrain ing devices in a fie ld in w hich a lm o st all th e available in fo rm a tio n is p ro d u c e d by th e m an u fa ctu re rs o f machines. it needs to be appreciated t h a t a lm o s ta llm a c h in e s a re c o stly and in general in fe rio r to fre e w e ig h ts and pulley devices in o ffe rin g b road s p e c tru m c o n d itio n in g o f th e m uscu loske le ta l and n e u ro m u s c u la r system s if m achine re h a b ilita tio n is desired, th e n thesystem o f choice isstili pulleys: th e y are cheap, durable, e x tre m e ly versatile, safe and able to c o nd itio n three-dim ensionally using th e well-proven principles o f pnf. pulley systems can also be co nve rte d into d y n a m ic (isotonic-) te s tin g m achines by th e a d d itio n o f stra in gauges o r ac­ ce le rom e te rs a tta c h e d to a m in ic o m p u ­ ter, a m e th o d used successfully by th e autho r. o th e r m achines can be useful in isolating p a rtic u la r m uscle grou ps and p ro vid in g v a rie ty in tra in in g , b u t th e y should never be th e sole m eans o f rehabi­ lita tio n o r testing. the final c rite rio n is n o t a c o m p u te r p rin to u t, b u t a re tu rn o f th e a th le te to fu lly fu n ctio n a l, pain-free, long­ te rm p a rtic ip a tio n in his sp ecific sport. references m o s t o f t h e in f o r m a t io n w a s d e r iv e d fr o m t h e a u th o r 's p r e s e n t a tio n s a t t h e fo llo w in g c o n fe re n c e s : 1 .s iffm c ,t h e e rg o n o m ic s o fp h y s ic a ltr a in in g d e v ic e s a n d te c h n iq u e s : s e c o n d w its in d u s ­ t r ia l e n g in e e r in g c o n f. s c h o o l o f m e c h a n i­ cal e n g in e e r in g , u n iv e r s ity o f t h e w it w a te r s r a n d : 4 -5 feb 1 987. 2. s iffm c ,t h e b io m e c h a n ic s o f s a fe ty in e x e r­ cise. s e c o n d s a s p o rts m e d ic in e c o ngress, c a p e tow n. 14-16 a p r il 1 9 8 7 3. s iffm c , t h e p h y s io lo g ic a l a n d b io m e c h a n i c a lfo u n d a tio n s o fs a fe ty in e x e r c is e a n n u a l c o n v e n tio n o f n a tio n a l s t r e n g t h & c o n d i­ tio n in g assoc(nsca), las vegas, usa. 2 6 -2 8 j u n e 1 9 8 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) spinal cord injuries in rugby players a.t. scher, mb, chb, dmrd professor and head department of radiology university of stellenbosch and tygerberg hospital tygerberg 7505 republic of south africa r outine radiological examination o f the cervical spine — an aid in the preven­ tion ofseriousspinal cord injuries in rugby players. in 1 9 8 3 1 re p o r te d o n a ru g b y player w h o had su stain ed cervical spinal c o rd in ju ry in th e a b s e n c e o fa n y fra c tu re o rd is lo c a tio n , b u tc o n s e q u e n t u p o n severe c e rv i­ cal disc d e g e n e ra tio n , (scher 1983). this, to g e th e r w ith th e o b s e rv a tio n t h a t ru g ­ by players show ed x-ray changes o f se­ vere d eg e ne rative disease o f th e cervical spine,suggested th a t players w e re p ro n e to an e a rlie r o n s e t o f d e g e n e ra tiv e dis­ ease c o n firm a tio n o f th is su pp o sitio n as in v e s tig a te d by x-raying th e cervical s p in e o fa n u m b e ro fa s y m p to m a tic c lu b players (scher 1988). the re su lts in d ic a t­ ed th a to ld e r ru g b y players, in p a rtic u la r th o s e w h o play a s tig h tfo rw a rd s , arelike ly to have developed p re m a tu re c h a n g e s o f d e g e n e ra tiv e disease, fig. 1. the pres­ ence o f th e s e changes is o f m o re th a n a cad e m ic in te re s t, as th e risk o f spinal cord in ju ry is increased in th e presence o f d e g e n e ra tiv e disease. u n d er th e se c ir­ cumstances, th e s p in a lc o rd is vu lnerable to d a m a g e a fte r hyperextension in ju ry to t h e head o r neck, even in th e absence o f any fr a c tu r e o r d is lo c a tio n (scher 1983). t h e m a jo rity o fth e s e in ju rie s o c c u rin th e presence o f ce rvical spondylosis, (scher 1976). the c o rd is p in ch e d b e tw e e n th e d e g e n e ra te v e rte b ra l discs and osteo p h y te s a n te rio rly and p r o tr u d in g redun d a n tfo ld s o flig a m e n tu m fla v u m p oste ­ r io rly a p a rt fr o m d e g e n e ra tiv e c e rv ic a l spine cervical spine o f a 30 year old lock forward. note the large poste riorosteophyticspur(arrcwed) projecting into thespinal canal. vical spine o f an asymptomatic rugby player. disease, o th e r c o n d itio n s o f clinical im ­ p o rta n c e m a y be e v id e n t. these include fu s io n o f th e v e rte b ra l bodies o r evi­ dence o f a c o n g e n ita lly n a rro w spinal canal. fusion o f th e v e rtic a l b od ies e ith e r con g e n ita lo ra c q u ire d , decreases th e flexibil­ ity and n o rm a l range o f m o v e m e n t o f th e cervical sp in e and predisposes to ­ w ards tra u m a , fig. 2. in an in v e s tig a tio n in to th e rela tion sh ip betw e en cervical fu ­ sion and spinal c o rd injury, i show ed th a t su b je cts w ith fu s e d v e rte b ra e w e re p ar­ tic u la rly p ro n e to h y p e re x te n s io n s p in a l c o rd injury, even in th e a b s e n c e o f ra dio ­ logical evidence o f v e rteb ra l in ju ry (scher 1979). this in v e s tig a tio n also showed t h a t serious in ju ry co u ld re s u lt fr o m m in o r tra u m a s such as s im p le falls. som e in d ivid u a ls have c o n g e n ita lly nar­ ro w spinal canals, placing th e m a t g re a t m r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r i s k o f spinal c o rd injury, i f th e s a g itta l d i­ a m e t e r o f th e cervical canal a t any level is 10m m o r less, th e n any a d d itio n a l nar ro w in g d u e td tra u m a o r o th e r processes, win a lm o s t c e rta in ly re s u lt in s p in a l c o rd dam age w ith d ia m e te rs o f 10 i3m m , high risk is p resent. (w olfe e t al 1956). in v ie w o fth e a b o v e fin d ings and p o t e n t ia l dangers, th e necessity fo r routine radiological exam ination o f th e c e rvi calspineof all ru g b y play­ ers is e vid en t. it w o u ld not be unre asonable to suggest t h a t all ru g b y players, p a r tic ip a tin g regularly in cl ub orsocial rugby, u n d e rg o ra diolog­ ical e x a m in a tio n o f th e cervical spine a t least once d uring th e irp la y in g career. a lim ite d radiological ex­ a m ination o f th e cervical spine need c o nsist o f only a single lateral view. this is te c h n ic a lly a s im ­ ple, rapid, inexpensive (only o ne x-ray film is needed) e x a m in a tio n and does n o t expose th e p layertoexcessiveirradi ation. u tilising th e c rite ria p re ­ v io u sly discussed, th e r a d io g r a p h s c a n be evaluated fo r th e pres­ ence o f th e fo llo w in g changes: a) presence o f cervical v e r t e b r a l fu s io n s , e ith e r congenital orac quired. b)the presence o f a c o n ­ g enitally n a rro w spinal canal. o a ny changes o f d e ­ g e n e ra tiv e disease d)evidence o f previou s vertebral fr a c tu r e awareness o f th e pres­ ence o f these changes will enablea player, in co n ­ sultation with his medical practitioner, to decide w hether to c o n tin u e his active ru gb y career. if sig­ n ific a n t c h a n g e s are present, and p a rtic u la rly if nis playing p o s itio n is th a t o f a tig h t fo rw a rd , he will be well advised to either cease play i ng o r to change his playing posi­ tion to o n e w h e re he is •ess exposed to cervical stress. references i.sher a t . cervical s p in a l cord injury w ith o ut evi clenceof fra rtu re o r dislo­ cation. s a fr med j 1976; june 1988 vol 3, no 2,1988 | 5 0 :9 6 2 2. s c h e r at. c e rv ic a l s p in e fu s io n a n d t h e e f ­ fe c ts o f in ju ry . s a f r m e d j 1 9 7 9 : 5 6 :5 2 5 . 3. s ch e r a t .s e rio u s c e rv ic a l s p in e in ju r y in t h e o ld e r ru g b y p la y e r.s a fr m e d j 1 9 8 3 : 64:138. 4. s ch e r at. p r e m a t u r e o n s e t o f d e g e n e ra tiv e disease o f t h e c e rv ic a l s p in e in r u g b y players. (s u b m itte d f o r p u b lic a tio n ). 5 .w o lfe b s ,k h iln a n im & m a lis l .t h e s a g itta ld i a m e te r o f t h e b o n y c e rv ic a l sp in a l canal a nd its s ig n ific a n c e in c e rv ic a l s p o n d y lo s is j m t sinai h osp 1 9 5 6 ; 2 3 :2 8 3 . a 4 v r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) u staptog op pad na gesondheid avermeulen, b.sc. fisioterapie hfh weich, m.d., f.a.c.c. departem ente fisioterapie, tygerberg hospitaal en interne ceneeskunde (kardiologie eenheid), fakulteit ceneeskunde universiteit van stellenbosch en die bayer kliniese navorsingseenheid/ a bstract the c a rd io lo g y u n i t o f th e d e p a r tm e n t o f in te rn a l m edicine o f th e 'faculty o f medicine', u n iv e rs ity o f s tellenbosch, u n d e r th e le a d ersh ip o f p ro fe s s o r hfh weich, in c o -o p e ra tio n w ith th e d e p a r tm e n t o f physiotherapy, tyger­ b e rg hospital, ow e th e ir su cce ssfu l c a r­ d ia c re h a b ilita tio n p ro g ra m m e to th e fa c t t h a t p a tie n ts are e ffe c tiv e ly m o t i­ v a te d a n d e n c o u ra g e d to b e c o m e f i t a n d t o s t a y f it th ro u g h re g u la r walking. a suc­ ce ssful re h a b ilita tio n p ro g ra m m e c u l­ m in a te s in a c lim b u p table m ou n ta in . these h ik in g tr ip s were in tro d u c e d in 1982 as p a r t o f th e ir re h a b ilita tio n p ro g ra m m e s ix ty -fiv e p e rc e n to fth e p a tie n ts w h o p a rtic ip a te d in re h a b ilita tio n a re s till a c tiv e ly involved. the d r o p o u t r a te is lo w in c o m p a ris o n w ith o th e r s tu d ie s u n d e rta k e n b o th lo c a lly a n d overseas. inleiding en agtergrond d it is alom bekend d a t'n p asie n t na 'n har taanval psigiese p ro b le m e o n d e rv in d , v e ra lg e d u re n d e d ie e e rs te d rie w e k e tu is w a n n e e rh y g e w o o n lik b e g in o m 'n n u w e beeld van h o m s e lf asiem and m e t 'n hart letsel, o p te bou. 'n v erskeidenheid van p ro b le m e m ag o n ts ta a n ,o n d e ra n d e re : — swak m e n s e v e rh o u d in g s — o o rg o d s d ie n s tig h e id — to e v lu g n e e m t o t d ra n k — o o rm a tig e o e fe n in g com m y s e lf te b e w y s l — te bang o m enig e a k tiw ite it te o n d e rn e e m — a n g s e n depressie — verlies aan libido, ste rkte , e n e rg ie en o n a fh a n k lik h e id 123 m e t d ie re g te le id in g v e rw e rk pasiente h ie rd ie p ro b le m e makliker. cereelde oefen ing v e rh o o g 'n m ensselig gaam like sowel as geestelike welsyn. w etenskaplikes w a t die sie lk u n d ig e uit w e rk in g van 'n g e re e ld e o e fe n p ro g ra m b e s tu d e e r h e t,a-5-6 h e t o p g e m e rk d a t na m a te m e n s e fik s e rw o rd ,w o rd h u lle m e e r — o p e n h a rtig — o n ts p a n n e — na b u ite le w e n d — s e lfo n d e rh o u d e n d — v e rb e e ld in g rv k — vol s e lfv e rtro u e — stabiel navorsing h e t aan die lig g e b rin g d a t o efe n in g d o e ltre ffe n d e ra s kalm eerm id dels s p an n in g v e rm in d e r.3 6 d it is ook bekend d a t oefeni ng 'n persoon: — e m o sion e el p o s itie f instel — se angs, s p a n n in g en depressie v e r­ m in d e r — se slaap en o n ts p a n n in g b e v o rd e r — se e n e rg ie la a t to e n e e m — se v ita lite itv e r h o o g — se k o n s e n tr a s ie , u it h o u v e r m o e , p o s tu u r, v o o rk o m s , s e lfb e e ld en sosiale aanpassing ve rb e te r. o efe n in g v e rh o o g dus die k w a lite it van le w e 57-8 die re g te leiding is v a n d ie u ite rs te b e la n g v ir v o lk o m e re h a b ilita s ie die v o o rd e le van fisieke fik s h e id w o rd g e b ru ik o m psigiese fiksheid teverkry. 'n o m vattende o e fe n p ro g ra m , d e u rd ie d e p a rte m e n te fisioterapie, t ygerberg hospitaal en in­ te rn e geneeskunde, (k ardiologie een­ heid) fakulteit geneeskunde, universiteit van stellenbosch, is ingestel. die sukses v a n d ie re h a b ilita s ie p ro g ra m is te d a n k e aan 'n d o e lg e rig te m o ti veringsaksie o m p asiente aan te m o e d ig o m f iks te w o rd en daarna fik s te bly. die p ro g ra m begin in die hospitaal, gaan o o r in hoofsaaklik s ta p o e fe n in g e tu is t o t d ie p a s ie n t inskakel by 'n o e fe n p ro g ra m in die hospi­ taal w a a rn a h y "u itp a s s e e r" t o t gereelde tu is o e fe n in g e e n b e rg k lim u its ta p p ie s . o n g e v e e rtw e e weke, w a n n e e rd ie pa­ s ie n t o n ts la a n w o rd , w o rd van hom verw ag o m 2 0 0 m e te r te stap, asook e e n s te ltr a p p e te k lim . 2 .s e k o n d e r e r e h a b ilita s ie (o efen p r o g r a m tu is e n in g lm n a s iu m in h o s p ita a l) tuis w o rd hy aangem oed ig o m daagliks te g a a n s ta p .h y beg in m e t 200 m e te r en sta p dan elke dag 50 m e te r verder, june 1988 vol 3, no 2,19ffl omvang van kardiale rehabilitasieprogramme l.p r im e r e r e h a b illt a s ie d n te n s ie w e e e n h e id e n s a a l) b e d ru s w o rd v ird ie e e rs te d rie d a e n a , 'n h a rta a n v a l v o o rg e s k ry f, asook ' k a lm e e rm id d e ls o m te v o o rk o m d a tn m o o n tlik e s p a n n in g s to e s ta n d /n a d d i sionele las o p sy h a r t sal plaas die pa­ s ie n t w o rd wel to e g e la a t o m se lf te e e t en a a n g e m o e d ig o m sy to n e te be w eeg en d ie p a sem h aling soe fe n in g e te doen. na o n g e v e e r'n ve rd e re 5 dae m ag die pasient, indien d aa rgeen komi plikasiesisnie,begin u its itin n gemak stoel. eers v a n a f dag 5 t o t 6 m ag die p a s ie n t b egin s ta p daarna w o rd die h oeveelheid o e fe n in g w a t hy to e ­ g e la a t w o rd , daagliks v e rm e e rd e r. na r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) c n d a th y m e td ie e e rs te o p v o lg b e s o e k een k ilo m e te r m e t gem a k kan stap. qndra die p asien te een k ilo m e te r kan % p, w ord hy a a n g e m o e d ig o m elke dag een m in u u t la n g e rte stap, to td a t h v v i r 30 minute aaneen kan stap binne 6 weke b e h o o rt hy 3 t o t 4 kilo­ m eter p e r dag te stap. o ngeveer hier die tvd w ord 'n insp an n in g s-e lektro ka rd iog ra m (ekc) u itge voe r. in tyger berg hospitaal w ord die oefenm g stoets o p 'n tra p m e u l vo lgens die bruce-protokol g e d o e n .; w anneer die p a s ie n t v ir die oefen klasse g e k e u r w ord, m o e t die kai oloog, volgens die re s u lta te van die inspannings-ekg, v ir d ie p a s ie n t n veilige to e la a tb a re m a k s im u m hart spoed bepaal. tydens die oefenings kiasse w o rd g e p o o g d a t h ie rd ie pols spoed nie o o rs k ry w o rd nie. di6 g ro e p g e ke u rd e pasien te o e fe n d rie k e e rp e rw e e k ,o n d e rto e s ig ,in d ie hosp itaa l. 'n g e n ee she e r m e t 'n volledige resussitasietrollie, n fis io te r a pe u t,'n nehabilitasiesusteren'ndieet ku nd ig e is a lty d by die oefensessie te e nw oo rd ig .'n maatskaplike w erkeris ook o n m id d e llik beskikbaar o m aan d a g a a n e n ig e m a a tsk a p lik e p ro b le m e teskenk. pasiente m e t in fe rio r infarksies w o rd v ie r weke p o s t in fa rk s ie na d ie oefen ing kla s g estuu r, te rw y l diegene m e ta n te rio re n m ee rg eko m plise e rde infarksiesses weke p ost infarksie nadie klasse gaan. die redes v ir die vroe e in­ s is t in g is o m die la n g n ie -a k tie w e tyd p e rk tu is te v e rk o rt, o m d ie p a s ie n t in d ie o efen kla s te k ry v ir m o re le onder s te u n in g v o o rh y te ru g k e e rn a s y w e rk en o m k o n ta k te m aak m e t a n d e r pafie s u u a t e van 1 0 0 p a s ie n t e wat vanaf • 8 4 1 9 6 7 vir s t a p t o g t e g o e d g e k e u r is 09; v e r h u is siente b in n e die groep. d ie o e fe n p ro g ra m bestaan u it vie ro p w a rm in g s o e fe n in g e w a a rna die pa­ s ie n t v i r 'n v a s g e s te ld e t y d 'n ro n d te -o e fe n in g doen, w a t saam gestel is u ittie n is o to n ie s e o e fe n in g e op vasgestelde k o n tro le p u n te w o rd die p a s ie n t se p o ls te m p o gekon troleer, s o d a t d it nie die m a ksim u m toelaatbare h a rts p o e d o o rs k ry n ie indien d it h o e r is, m o e t die p a s ie n t eers rus. n a m a te die p a sie n t fik s e r w ord, kan hy die ro n d te -o e fe n in g m e e rm a le in die vo o rg e s te ld e ty d herhaal. die oefeningsessie w o rd afgesl u it d e u r v y f m in u te o p 'n sta tie s e fie ts te trap. die ty e w a t v ir die ro n d te -o e fe n in g e to e g e la a t w o rd , w o rd in ta b e l i voor gestel: m eka a r nod ig in 'n g ro e p s v e rb a n d om m e k a a rte m o ti ve e re n 'n g roe psg e eso p te bou. o n d e rv in d in g h e t o ok g e to o n d a t die o o rg ro te m e e rd e rh e id van die pasiente, veral d ie w a to o rm a s s a is, n ie b e la n g s te l o m t e d r a f nie en d a t sta p v ir h u lle 'n be te r aan va arb are a k tiw ite it is daarom is in 1982 b e s lu it o m m aant a b e li: ontledinc van rondte-oefeninge aifje 1988 vol 3, no 2,1988 w e k e in o e f e n p r o g r a m 1 2 3 4 5 6 7 8 9 10-11 1 2 -1 3 tyd (m in u t e ) geen b e p e rk in g geen b e p e rk in g geen b e p e rk in g geen b e p e rk in g 10 15 20 25 30 3. t e rs ie re r e h a b iilta s le (l a n g te r m y n s t a p p r o g r a m ) na v o lto o iin g van d ie o e fe n k u rs u s (3 t o t 4 m aande) w o rd die p a s ie n t w e e r aan 'n inspannings-ekg o n d e rw e rp . hulle v o rd e rin g w o rd nagegaan en 'n n uw e m a k s im u m to e la a tb a re h a rt­ spoed w o rd bepaal vo lg e n s s ta n d a a rd p ro s e d u re die p asien te kan dan v o o rtg a a n m e t d ie o e fe n p ro g ra m , m a a r h ulle o e fe n s o n d e r toesig. hulle k o n tro le e r hul eie h a rts p o e d en is v ir h u ls e lf verant woordelik. totstandkoming van die staptogte o n d ervinding h e t getoo n d a t die pasient as in d iv id u d ie m ee ste van sy p ro b le m e b y vo o rb e e ld kardiale neurose, v e rw e rk o f o o rk o m h e t te rw y l s y fa m ilie tu is nog p ro b le m e d a a rm e e o n d e rv in d het. dik wels w o rd die p a s ie n t tu is soos 'n breek b are kle in kosbaarheid behandel, te rw y l h y e in tlik fis ie s te n volleg e reh a bilite e rd is. pogings m oe s dus aangew end w o rd o m ie ts a d d is io n e e lb y d ie o e fe n in g k la s s e te voeg o m h ie rd ie p ro b le m e te o o rb ru g . v o o rlig tin g d e u rm id d e l van lesingseen keer p e r m aa n d en g ro e p sb e sp re kin g s w a td ie w e d e rh e lfv a n 'n h a rtp a s ie n tk a n byw oon, h e t h e e lw a t gehelp, m a a r d it was nog steeds nie g e n o eg n ie die pasiente w ou o ok graag v e rd e r as n e t d ie o efen kla s vorder. hulle w ou uitdag ings he s o d a t h ulle aan h u ls e lf en die fa m ilie k o n b e w y s d a th u lle te n v o lleg e re ­ h a b ilite e rd is en 'n n o rm a le lewe kon lei. o n d ervinding h e t getoo n d a t die m eeste van die p asien te v o o r h ulle harta a nva l v a n n a tu re n ie g e n e ig w a s o m o e fe n in g e o p eie in is ia tie f te d oe n nie, en d a t die o e fe n p ro g ra m van 3 t o t 4 m aa n de nie g e n o eg was o m hul lewenswyse p e rm a ­ n e n t te v e ra n d e r n ie die p asiente h e t h o e v e e ih e id r o n d te s 1/2 ro n d te -o e fe n in g ro n d te -o e fe n in g voile ro n d te -o e fe n in g en sta p voile ro n d te -o e fe n in g en d r a f een voile ro n d te ± 2 ro n d te s ± 3 ro n d te s ± 4 ro n d te s ± 5 ro n d te s delikse s ta p to g te te organiseer. stap to g te w o rd a an g en a am g em a ak s o d a t die p a s ie n t d it as 'n m aklike en aanvaar­ b are m a n ie r sien o m saam m e t sy gesin ty e in die v ry e n a tu u r d e u r te b rin g . die p a s ie n t w o rd d us aan iets b lo o tg e s te l w a a rin h yw e rk likb e la n g s te l.w a th y s a a m m e t sy gesin kan g e n ie te n w a t m eeraan v a a rb a a ris as a n d e r v o rm s van stra w w e f isieke a k tiw ite ite die s ta p to g te dien as 'n o n tv lu g tin g in die vrye n a tu u r o m na die p a s ie n ta s g e h e e lo m te s ie n .n a a m lik lig gaam , siel en g ee s die re su lta te m e t hie r­ die b e n a d e rin g is ind rukw ekke n d. die p asiente w o rd volgens die re su lta te v a n d ie tw e e d e in s p a n n in g s-e k g g e k e u r v ir die s ta p to g te . e lke d e rd e s a te rd a g v a n e lk e m a a n d k o m die p asiente m e t fa m ilie en v rie n d e b ym e ka a r v ir die u its ta p p ie hulle stap tu sse n 12 t o t 20 k ilo m e te r p e r dag. 'n g e n e e she e ren fisio te rap e utverg e se ldie g ro e p elke keer. d ie s ta p to g w o rd afges lu itm e t'n g e s e llig e b ra a i.d ie u its ta p p ie s h e t m e t v e rlo o p van ty d u itg e b re i van s le g s 'n g e w o n e s ta p to g n a m o e ilik e k lim roetes en selfs naw eekuitstappies. die p ra g tig e berg w e reld van die boland leen h o m t o t vele a n d e r sko usp ela gtig e dag u itstap p ie s w a tg o e d b e n u t word. die u its ta p p ie s d ie n as 'n spesiale u itd a g in g v ird ie pasient o m te k a n b e w y s d a th u l hul p ro b le m e v o lk o m e o o rk o m het. resultate van oefenprogramme slegseen s te rfg e v a l h e t in d ie oefenklas vo o rg e k o m s e d e rt die re ha bilitasiep ro g ra m in 1974 begin is. d ie o o rle d e n e k o n te n sp yte van a ktiew e resussitasie nie b y g e b rin g w o rd n ie s ta tis tie k e to o n 'n s ty g in g v a n d ie a a n ta l p asiente w a t s e d e rt 1984 aan die s ta p ­ to g te deelneem : 1984 — 1 4p a s ie in te 15r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 1985 — 25 pasiente 1986 — 41 p asiente 1987 — 65 pasiente g e e n o n g e v a lle o fs te rfte s is n o g ty d e n s d ie s ta p to g te o n d e rv in d nie. die re su lta te van 100 ope e nvo lg e nd e pa­ siente w a t v a n a f 1984 t o t 1987 v ir die s ta p to g te g o e d g e k e u r is .w o r d in fig u u r (d a a n g e to o n . bespreking van oefenprogramme navorsing o o r d ie hele w ereld to o n d a t d ie p rim e re en sekondere rehabilitasie fases goed is, m a a r d ie tersie re re­ h a b ilita s ie w o r d v e rw a a rlo o s .12 die s ta p p ro g ra m is b e s o n d e rg o e d in d ie ver band, w a n t d it gee aandag aan daa rdie fa se t van rehabilitasie w a t h e lp o m d ie pa­ s ie n t se lew enswyse p e r m a n e n t te verander. vyf-en-sestig p e rs e n t van die p asiente w a t by die p ro g ra m ingeskakel word, hou d a a rm e e vol en nee m nog steeds a k tie f daaraan deel. in ve rg e ly k in g m e t a n d e r s tu d ie s 12 is d ie u itv a ls y fe r van 35% baie la a g .d ie re d e v irh ie rd ie la e u itv a ls y fe ris , vergeleke m e t a n d e r s tu d ie s plaaslik en oo rse e 12 w a a rskyn lik te d an ke aan die fe it d a t sta p in die n a tu u r v ir p asiente m e tk a rd ia le p ro b le m e n ie v e rv e lig is n ie en d us m e e r aanva arb aa r is as a n d e r s tra w w e r fisie ke a k tiw ite ite . s odoende sorg d it v ir b e te r p a s ie n t sam ew erking. die redes v ird ie s ta k in g van 28% van die pasiente kan to e g e s k n /f w o rd aan werks o f v e rv o e rp ro b le m e , o f d a t d ie p asiente voel h ulle g ee n v e rd e re re h a b ilita sie n o ­ d ig h e t nie. van d ie 4% wa t o o rle d e is, is 1 % d o o d as g evolg van 'n m o to ro n g e lu k , nog 1% d o o d as g evolg van kom plikasies na 'n la p a ro to m ie v ir 'n p e p tie se ulkus. die res iso o rle d e a sg e vo lg van komplikasies van hul h a rtle ts e l. pasiente in d ie te rs ie re re ha bilitasiefase is g e n e ig o m te v o lh a rd e n v e rk ie s o m per­ m a n e n t deel te wees van d ie g ro e p o m m e k a a rts m o tiv e e rty d e n s d ie s ta p to g te d itd ie n a s 'n b ro n v a n in s p ira s ie v irn u w e p asiente w a t to e tr e e t o t d ie rehabilita siep rog ra m . na d ie u its ta p p ie s voel d ie p asiente sp re e kw o o rd e lik'tin to p o f th e w o rld" die fa m ilie en v rie n d e sien h ul w e d e rh e lf/ vader, m o e d e r o f v rie n d as ie m a nd w a t w e e r'n geso n de n o rm a le lewe kan lei en d it b rin g hulle as fa m ilie en v rie n d e baie n ad e r aan m ekaar, in baie gevalle baie n a d e ra s v p o rd ie in fa rk s ie . di t is v e rb ly d e n d o m te sien d a t n a m a te d ie p asiente fik s e r w o rd , h u lle w e e r hul s e lfv e rtro u e h e rw in . na v o lto o iin g van die kursus is hulle gew oonlik goed aange pas, vol s e lfv e rtro u e en m eestal b e te r a f as v o o r hul hartaanval. ons s tu d ie s h e t ook die vo lg e n d e bevestig: — p asiente is m e e r o n ts p a n n e — v e rb e te rin g van w e rksitua sie — v e rb re d in g van le w e n su itkyk — e e t en le e f m e e r gesond — lib id o en s la a p p a tro o n v e rb e te r hulle is a s 'tw a re n u w e m e n s e . hulle hele le e fw y s e v e ra n d e r p e rm a n e n t, d ie k w a lite it van h ul lewens w o rd verbeter. soos'n pasient een k e e rty d e n s 'n groeps besp rekin g o p g e m e rk het: "m y h a rta a n ­ val is d ie beste d in g w a t n og o o it m e t m y k o n g e b e u rh e t!" 1. w eich hfh. die p a s ie n t m e t 'n h a rta a n ­ val. d o m in e e e n d o k te r b y d ie siekbed. n c kerk u itg e w e rs, 1 9 8 2 9 0 96. 2. h a c k e tt, t h o m a s p, c assem n ed h. psy­ c h o lo g ic a s p e c ts o f r e h a b ilita tio n a fte r m y o c a rd ia l in fa rc tio n . r e h a b ilita tio n o f t h e c o ro n a r y p a tie n t, 2 4 3 ■ 252. 3. p ric e h, o b e l tlp, s c h o tt m illa r rn. psy­ c h o so c ia l a s p e c ts o f c a rd ia c -p a cin g . s a m e d ie s e t yd skrif, a p r il 1 9 8 0 :580 582. 4. m e tr o p o lita n h o m e s t ru s t lewens. 'n g esonde gees in n g e s o n d e liggaam . fiks v ir d ie le w e (p a m fle t). 5. c u re to n tk. im p ro v e m e n t o f p sych o lo g ­ ical s ta te s b y m e n a s o f e xe rc is e fitn e s s p ro g ra m s . j o u rn a l o f a s s o c ia tio n fo r p h ysical a n d m e n ta l r e h a b ilita tio n 17, 1 9 6 3 14 17. 25. 6. m ichael d. s tress a d a p ta tio n th r o u g h ex­ e rc is e r ese arch q u a r te r ly 28, 1957, 50-54. 7. h ig g e n s jb. m e t fik s h e id k o m jy verder. r e h a b ilita tio n in sa, j u n e 1981, 59 • 62. 8. b e s te r cl, m e y e r sa. die te ra p e u tie s e w a a rd e v a n s p o rt. r e h a b ilita s ie in sa. d e s e m b e r 1 9 8 2 : 7 8 83. 9. le ste r fm, s h e ffie ld lt, reeves tj. elec­ tr o c a r d io g r a p h ic c h a n g e s in c lin ic a lly n o r m a l o ld e r m e n fo llo w in g n e a r m ax­ im a l a n d m a x im a l e x e rcise c ircu la tio n 36 . 5, 1987. 10. s h e ffie ld lt, m a lo o f ja, s a w y e r ja, rort m a n d. m a x im a l h e a r tr a te a n d tre a d m ill p e r fo r m a n c e o f h e a lth y w o m e n in rela­ tio n t o age. c ir c u la tio n 5 7 . 79, 1978. 11. w e ich hfh. o e fe n p r o g r a m na m io k a rd i ale in fa rk s ie t h e s a jo u r n a l o f continu­ in g m e d ic a l e d u c a tio n vol 3, n ovem ber 1985. 61 69. 12. d is h m a n rk. e xercise c o m p lia n c e : a n e w v ie w f o r p u b lic h e a lth . physician and s p o r ts m e d ic in e vol 14, n r 5, m ay 1986 . 1 2 7 1 4 2 ^ june 1988 vol 3, no 2,15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ultraman big better bester' this g ru e llin g c o m p e ti­ tio n c o m p ris e d th e fo l­ lowing: c o m p u ls o ry e ve n ts : vasbyt 160km cycle race hansa duzi canoe m ara­ th o n sunday tim es/leppin iron man comrades m a ra th o n o p tio n a l e vents jse. m a ra th o n m idm ar mile swim argus cycle race two ocean's m a ra th o n the ultra man competition has f i ­ nally d raw n to a close w ith a sigh o f relief fr o m m an y a c o m p e tito r no doubt! praise m u s t be m e n tio n e d to all th o s e c o m p e tito rs successfully c o m p le tin g th e c om rades m ara th o n. a special m ention to one o f o u r stars — nick bester f o r his m a g n ific e n t display o f guts and d e te rm in a tio n . to q u o te th e majestic fordyce: "i was a t one stage worrying a b o u t m ark page, b u t m y se­ conds w a rn ed m e ra th e r to w o rry about bester w ho was racing m e all th e way_" besters tim e f o r th e c om rades was in incredible 5:39.00 w h ic h e a rn e d h im a full 100 p o in ts and th e ultraman ti­ tle. priscilla carlisle was th e fir s t lady h o m e n a rro w ly m issing h e r silver medal in a tim e o f 7:30:39. n e v e rth e ­ less, this p e rfo rm a n c e by priscilla se­ cures h e r f i r s t place in th e lady's c o m ­ petition. the veteran's c o m p e titio n proved to be both in te re s tin g and e x tre m e ly close­ ly contested. a s ta g g e rin g 34 veterans “ including a lady, carol h o n ne yse tt, wni be collecting m edals the m ain race througho ut th e c o m p e titio n was be­ tween tw o s tro n g , c o m m itte d and ex­ trem ely ta le n te d a th le te s graem e rope-ellis and g e o ff m a tth e w s these tw o trojans b a ttle d to th e v e ry end, only to see t h e roper take th e honours y f l 3 c om rades tim e o f 6:36:30 and 696,05 p o in ts 9 iv in g h im an incredible 3 rd p o s itio n overall. w > e ts were th e nam e o f th e game, es pct ^ a k1,0 th is ve a rs ultraman com “ and le t a t h o u g h t be _ apdreq r o r th o s e c o u ra g e o u s a th le te s no 2,1988 w h o a tte m p te d th e c om rades b u t fa ile d to fin is h th e 89,9km route. the sponsors, ciba geigy, and th e o r ­ ganisers s ports in te rn a tio n a l w ould like to c o n g ra tu la te all th o s e c o m p e tito rs w h o can d e se rve d ly call th e m se lve s "ultramen" (and ladies!). ultraman ladies positions 1 carlisle pricilla 2 meakerjane 3. 8antock5ally 4. bargate karen 5. laingchancelle 6. leonard annemarie 7. eardley sandra margot 8. honneysett carol 494.60 483.83 479.41 406.45 390.31 377.29 221.87 vet 122.27 overall positions listing name pos jse vasbyt duzi midmar ironman argus 2 oceans comrades total bester nicolaas 1 100.00 99.81 92.27 7780 100.00 100.00 96.49 100.00 766.37 oejager pierre 2 84.72 9945 7661 61.52 98.74 97 39 100.00 81.50 699.93 graeme pope-ellis 3 85.22 92 81 100.00 51.43 9705 94.07 93.38 82.09 69605 fletcher cordon 4 75.55 83.89 90.71 81 35 80.28 9368 98.56 82.96 686.98 janos george 5 92.02 96.71 87.41 67.15 93.47 98.07 8021 67.48 682.52 matthews geoff 6 81.77 90.77 81.90 78.87 86.58 92.24 85.46 7306 670.56 moolman martin 7 73.54 99.35 7373 60.06 91.24 99.85 85 35 71.01 654.13 vandermerwesam 8 74.55 88 78 8084 10000 72 87 93.43 75 30 57.95 643.72 van dermerwe martin 9 77.05 89 75 8084 7898 77.69 93.43 75.18 69 31 642.23 lochnerlochi 10 80.82 96.51 58.48 32.22 90 46 94.61 83.98 76.71 613 79 van tonder phillip 11 84.02 97.76 86.64 31.80 8740 94.61 72.60 55.60 61043 britten steve 12 61.28 88.74 5749 86.22 71,77 9252 72.16 72.10 602 28 wiimot michael 13 6670 84.10 8716 4969 78.76 94.84 7170 68.29 60124 jones stan 14 76.14 8416 49.50 86.22 8205 89.42 74 46 5662 598.57 uysroget 15 70.25 90.41 74.34 70.63 6726 91 24 72.03 59 30 595.46 williamson nome 16 81.14 89.30 4361 7738 78.46 86.58 89.87 43.56 58990 poole kenneth 17 8171 71.37 51.74 58.25 72.34 90.98 8926 6956 585.21 bothamax 18 75.06 665 0 73.58 56.30 6945 8453 79.10 72.79 57731 benson lan 19 80.69 94.47 74 74 550 83.31 9551 58.29 66.55 559.06 cooper colin 20 78.70 84.82 5676 2463 77 30 91.42 84.47 56.92 555.02 nick bester r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) international congress in cape town t the south african rugby board in c o n ju n c tio n w ith th e south african sports m edicine associa­ tion is arranging an inter ___________ national congress on in­ ju r ie s in r u gby a nd o th e r c o ntact sports. this congress will be held in cape town, a t th e cape sun on 21, 22 and 23 march 1 98 9 and will fo rm p a rt o f th e south african rugby board's c entenary celebrations. a provisional p ro g ram m e has been drawn-up: i training fitness basic principles the rugbyplayers approach to fitness coaches assessment o f fitness biokinetic approach to fitness fitness in boxing fitness in soccer fitness in th e older p a rticip an t the psychologist's role in s port diet and food selection in build aerobics in train ing ii risks in contact games statistical review o f injuries injuries in boxing injuries in soccer iii injuries in rugby risks in rugby statistical review international statistical review sa school rugby statistical review senior rugby discussion 1. rugby football union 2. scottish rugby union 3. irish rugby fo o tb a ll union 4. welsh rugby union 5. australian rugby football union 6. new zealand rugby football union 7. federation francaise de rugby iv sports injuries and their treatment a. head injuries — diagnosis o f concussion — t re a tm e n t and evaluation b. neck injuries serious spinal injuries in sport c ervical spinal injuries — diagnosis/x-rays transport o f injured patients cervical spine in ex-players c. facial injuries pattern o f facial injuries t re a tm e n t o f m andibular and m axillar injuries d. mouth — teeth teeth injuries the use o f m outhguards in — boxing/rugby the making o f a m o uthguard e. eye and ear injuries injuries to eyes ear h aem atom a f. injuries in abdomen, tho­ rax kidneys and genital organs thorax and abdominal injuries renal injuries injuries to genital organs g. shoulder girdle injuries s houlder dislocations acromioclavicular injuries h. upper limb injuries arm and elbow injuries to wrist, hand and fingers in contact sports i. knee injuries a n atom y o f th e knee evaluation o f th e knee injuries patterns diagnosis o f knee injuries the use o f th e arthroscope r e h a b ilita tio n a f t e r k n ee injuries j. ankle injuries diagnosis o f ankle injuries t re a tm e n t o f injuries rehabilitation o f ankle injuries k. muscle, nerve and soft tissue injuries muscle injuries t re a tm e n t o f muscle injuries cramps in leg muscles derm atological problem s in rugby injuries at the site of the in­ jury on th e field in th e boxing ring role o f th e referee m inim um 1st aid requirem ents use o f local anaesthetics vi first aid services o rganization a t a m ajor stadium duties o f first aids training o f personnel accident services vii prevention of injuries training and fitness s trapping and taping pads and braces rugby boots and studs p rotective aspects in boxing viii touring sides ix insurance of players x rehabilitation role o f physiotherapy role o f biokinetics rehabilitation o f serious injuries in addition to this, tim e will be set aside fo r a south african knee and ar­ throscopic society symposium and sessions fo r fre e scientific papers for any prelim inary enquiries please contact: sally elliott, post graduate educational centre, university o f cape town. tel: (021) 47-1250. first national congress of the south african physiotherapists acupuncture association incorporating: the first national congress of complementary therapies royal hotel, durban. 27/28 th august 1988 for enquiries please contact: mr. c liggins, chairman, physiotherapy! school, king edward vlll hospital, private i bag congella 4013. tel: (031) 25-3511} ext 416.; marga ret si m pson, continuing! medical education unit, u n iv e r s i t y o f n a | tal. medical school, po box 17039 congel-j la 4013. tel: (031) 25-4211 extn. 327 june 1988 vol 3, no 2, 18 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) guidelines for authors scientific articles 1 the journal o f th e south african sports medicine association publishes original and reviewarticlesfrom all dis­ ciplines relevant to sports medicine. the journal aims to cater fo r th e diverse interests o f m em bers o f th e medical and para-medical professions and th e sporting public interested in th e scientific and medical aspects o f sport. 2. material subm itted fo r publication in th e jsasma is accepted on condition th a t it has n o t been published else­ where. all nam ed authors m ust give signed consenttopublication,andthe jsasma does not hold itself reponsible forstatem ents m ade by contributors 3. all subm itted articles should be o f ap­ propriate scientific value and should have practical application in sports medicine. articles may be w ritte n in afrikaansorenglish. the contributions wil i be critically reviewed by a t least one appropriate referee whoisaspecialist in th e field o f th e s u b m itte d material. this review will be passed on a double­ blind approach (both a u th o r and referee will remainanonymoustoeach other). the referee's com m ents will be sent to th e a u th o r to g e th e r w ith th e evaluation o f o n eof th e editors accep­ tance o f th e papers fo r publication is based onoriginality and quality o f th e work as well as on th e clarity o f in­ terpretation. the papers will be pub­ lished in th e order o f acceptance and not in th e order o f submission. the publisher reserves copyright and reproduction rights o f all published material, and such material may not be reproduced in any form w ith o u t th e publisher's w ritte n permission. all manuscripts to be directed to: d o o e d ito r' j o u rn a l o f sasma, po box 3909, randburg 2125. preparation of the manuscript h^?wscripts should be typew ritten, ouble-spaced onsheetsof uniform size, n o ^ rg e rth a n 21x29.7cm (din a4) w ith a ^ f 9in on th e le ft an contributions to be subm itted in duplicate (one original w ith illustrations suitable fo r reproduction and tw o com plete copies including copies o f figures and tables). only theoriginalcopy will bere tu rn e d to th e author(s) in case o f revision or rejection. the cover page o f th e m anuscript should list th e following inform ation: (i) concise b u t inform ative title (ii) key words (maxim um 5-8) (iii) author(s) initials and name(s) (iv) nam e and location o f institution w here th e investigations were car­ ried o u t (v) n a m e a n d a d d re s s o fth e a u th o rto whom communicationsconcerning th eco n trib u tio n should bedirected (iv) acknowledgementsof research sup­ p o rt and research gran ts the second page o f th e m anuscript s h o u d in c lu d e o n lyth e title o fth e artic le w ithout reference to th e author's names or affiliations. june 1988 vol 3, no 2,1988 the th ird page o f th e m anuscript should give an abstract o f th e scientific contents o f nom ore than 200 wordsand notexceedingonedouble-spaced ty p e ­ w ritte n page. the text o f them anuscriptshould bear ranged as follows: an introd uction describing th e pur­ pose o f th e work in relation to otherw ork in th e same field. material and methods: describe th e selection o f th e observational or ex perim entalsubjects clearly. id e n tify th e methods, apparatus and procedures in sufficientdetailtoallow otherw orkersto reproduce th e results. the results should be presented con cisely.thestatistical m ethod used should be named. authors m ust express units, quantities, and form ulas according to th e recom m endationsofthesystem e in­ ternationale (si units). all measurements should begiven in m etric units the discussion should emphasize th e n e w a n d im p o rtan ta s p e cts o fth es tu d y and th e conclusions t h a t follow fro m them . the practical implications o f th e study should be emphasized. illustrations and tables figuresconsistof all m aterial which can­ n o t be set in type, such as photographs and line drawings. (tablesare not includ­ ed in thisclassif ication and should n o t be submitted as photographs). in nocircum stancesshould original x-ray films befor warded:glossyprintsmustbesubmitted. tables and legends fo r illustrations should be ty p ed onseparatesheetsand should beclearlyidentified.tablesshould carryromannumerals,thus:l,ll,llletc,and illustrations arabic numerals, thus: 1,2,3 etc. tables should be self-explanatory and bear a short tit le abbreviations used should be explained in th e legend or a t th e bottom o f th e table. illustrations should be labelled with th e nam e o f th e firs ta u th o ra n d th e illustration num ber on th e top left-hand corner o f th e back side. references referencesshould be inserted in th e te x t assuperior numbers, and should be list­ ed a t th e e n d o f t h e a r t ic le in numerical order donotllstthemalphabetlcally. it is th e author's responsibility to verify references fro m th e original sources. referencesshould b e s e to u tin th e v a n couverstyle, and only approved abbrevi­ ations o f journal titles should be used; consultthejanuaryissueofindexm edl cus(n q l,p art1)fo rth e se d e tails names and initialsof allauthorsshould begiven unless th e re are m ore than six, in which case th e first th re e names should be given followed by ’e t al‘. first and last page num bers should be given eg. 1. noakestd. heartdisease in m arathon runners: a review. med sci sports exerc 1987;19:198-194. book references should be set o u t as follows: 19r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 1. peterson l , r e n stro m p. s ports injuries. t h e ir p re v e n tio n and tr e a tm e n t, 1st ed. south africa: justa and co ltd, 1986. 2. o ldridge nb: com pliance w ith exercise p rog ram s. in: pollock ml, s c h m id t dh, eds. h e a rt disease and r e h a b ilita tio n (ed 2). new york, jo hn w iley & sons, 1986:629-646. i f the more practical articles, review articles, papers presented at congress etc, do not need to comply with such strict guidelines" practical articles the m o re p ra c tic a l articles, review a r­ ticles, papers presented a t congress etc, do n o t need to c o m p ly w ith such s tr ic t g uid elin e s — length l en g th o f th e s e c o n trib u tio n s s h o u ld n o t how ever exceed 5-6 pages ty p e d in d ou b le spacing. all c o n trib u tio n s are to be s u b m itte d in duplicate. illustrations & tables baa/ head & sh ou ld e rs p h o to o f th e author(s) s h o u ld a c c o m p a n y a rtic le slides & p rin ts , graphs, ta b le s e tc on e ith e r c o lo u r o r b/w w h ich w o u ld c o m ­ p le m e n t th e a rtic le are w elcom ed. ta­ bles should c a rry rom an num erals and illu s tra tio n s a rabic n um e rals th u s 1,2,3 e tc references as fo r s c ie n tific a rtic le s si’ cists m iedicini s p c r t g g n i ilis k u n d i t ¥ t unutin grr« « * . < # • / ••ocrt* **•*-«» v'.-.o mir.k . of v ir + u & i h yi a w t fu 'i h w b j m _ failure coooio win m u n in your name n ir o v w liom trw matting mn. ' • -• :• :w * ' a f w m > mt'i'. mot ite* . t w o eosc -ix*c";/rcor!l.* i na leti u sou naiaat om cm tedoen. m i unaamouromatie* van ate posiys oew rw w oro □rrmg-ojr't-iyim . . . . . .,, |v, .. n ; p lease n o te : if you have n o t re tu rn e d e ith e r o f th e re p ly paid cards in se rte d in th e tw o p re v io u s e d itio n s o f th e sports m edicine journal, y o u r nam e will u n fo r tu n a te ly be re m o v e d fr o m th e m ailin g list. a c t now! dear editor i w o u ld like to re p ly to clive noble's editorial c o m m e n t on a lte rn a tiv e m e d i­ cine in th e 1987 vol. 2 no. 4 issue in w hich he discussed th e zola budd saga. i w o u ld like to answ er so m e p o in ts raised by clive noble, w ith re sp e c t to th e heel l i f t assessm ent d escribe d in th e a rtic le firstly, w h a t was n o t m ad e clear was t h a t th e p r a c titio n e r tr e a tin g zola budd was a c h iro p ra c to r, and he used a te c h n iq u e called a p p lie d kinesiology, w hich is th e use o f m anual m uscle te s t­ ing to evaluate b o d y fu n c tio n th ro u g h th e d y n a m ic s o f th e m usculoskeletal system. a p p lie d k inesiology is th e fa s te s t g ro w in g h e a lth system in th e w o rld today, a nd it is e x tre m e ly ac­ c u ra te in assessing s tr u c tu r a l balance. w hen assessing w h e th e r a heel l if t is re q u ire d o r n o t, th e p ro c e d u re is fa r fr o m a h it and m iss m e th o d . secondly it m u s t be u n d e rs to o d t h a t w h e n th e re is a s h o r t leg on o n e side o f th e body, all th e p o s tu ra l w e ig h t bea rin g muscles on th a t side will te s t weak. this is e xtre m e ly easy to d e m o n s tra te once all p o te n tia l p ro b le m areas are a d ju s t­ ed and c o rre c te d , f o r example, pelvis, spine, knees and fe e t, c e rta in m uscles will be te s te d on th e side o f th e b o d y w h e re th e s h o r t leg is suspected w ith th e p a tie n t lyin g on his back. w hen all m uscles te s t s tro n g , th e sam e muscles will be re te s te d w ith th e p a tie n t s ta n d ­ ing up. if th e m uscles b e c o m e weak, th e re is in d ic a tio n t h a t th e balancing s u p p o rt o f a l if t is needed. the p a tie n t can be te s te d w ith lifts o f va ry in g h e ig h ts u n d e r th e suspected d e fic ie n t sides, w ith th e in d ic a to r m uscles being re-tested fo r s tre n g th e n in g . w hen th e o p tim u m a m o u n t o f l i f t fo r th e p a ­ t ie n t is fo u n d , all th e in d ic a to r muscles will in s ta n tly s tre n g th e n . f u rth e rm o re , it should be n o te d t h a t tw o ty p e s o f leg le n g th im b a la n c e m ay be p rese nt. one is an a n a to m ic a l and th e second is a physiological. an a n a to m ic a l s h o r t leg re fe rs to a leg aletters t h a t is a c tu a lly a n a to m ic a lly s h o rt w hereas a physiological s h o rt leg jj s h o rt due to a s tru c tu ra l p ro b le m such as a p elvic ro ta tio n . the physiological s h o r t leg w ill re spond to th e norm al c h iro p ra c tic c o rre c tio n a n d th e re will be no n ece ssity f o r a heel lift, except in very, v e ry e x tre m e cases where th e re is a severe p elvic p rob le m , in these cases th e app lica tion o f a heel lift is n o rm a lly o n ly a te m p o ra ry measure to allow th e p a tie n t to re co ve r fro m th e acute phase o f back pain. the usual m uscle te s tin g p ro ce d u re s w ould have been used to e valuate w h e th e r o r n o t th e l if t was necessary. this w o u ld also answ er clive noble's s ta te m e n t where he claim s t h a t a n u m b e r o f th e cases tre a te d by ronald h o ld e r have had s c ie n tific a lly a ccura te ra diolo gica l leg le n g th m e a s u re m e n ts t h a t revealed equal leg lengths. the case t h a t responds b e t te r to th e a p p lic a tio n o f a heel l if t is th e ana to m ­ ical s h o rt leg, w h ic h i can o n ly assume m u s t have b ee n zola budd's problem . however, it m u s t be n o te d t h a t n o t necessarily are all anatom ical s h o rt legs tre a te d w ith heel lifts as v e ry o fte n th e b o d y is able to a d a p t and com pensate f o r th is d e fic it. a gain in th is case a leg le n g th d iffe re n c e show ing up on x-rays w ill n o t have th e associated weakness o f m uscle te s tin g , indeed an applica­ tio n o f a heel l i f t in th is case w o u ld be d e trim e n ta l. it m u s t also be p o in te d o u t th a t th e use o f heel lifts is n o t c o m m o n in c h iro p ra c tic and a p plie d kinesiology. p rob a bly 95% o f all p a tie n ts respond to th e c h iro p ra c tic a d ju s tm e n ts and m uscle b ala ncing p ro c e d u re s and do n o t need a heel lift. one fu rth e r p o in t is th a t we in th e chiro­ p ra c tic p ro fe s s io n fe e l m o s t s tro n g ly t h a t i f rule 92 was d on e away w ith and th e m edical and c h iro p ra c tic p ra c ti­ tio n e rs were allowed to w o rk to g ethe r, th e p a tie n t w o u ld be th e w inner. yours sincerely d r frans k r o m h o u t. w h a t d o th e read ers th in k ? suid-afrikaanse sportgeneeskunde vereniging application form aansoekvorm full member/volle lid r25 student member/studente-lid r5 name/naam: ... address/ad res: south african sports medicine association tel no/tel n r . .............. m a s a n o/m v sa n r . full member. m edicalpracm ionerfs vvhoarem em d efsof m.a.s.a voile lid: m e d ie s e p ra k tis y n s w a tie d e v a n d ie m v s .a is student m em ber medical s tudents m c lin ica l years. s tu d e n te -le d e :m e d ie s o s iu d e n ie in h u ik iin ie s e jare. applic ations for m em bership of s.a.s m .a s h o u ld b e s e n tto the secretary. s. a.s.m. a.. hatfield forum west. i067a rca d ia s tre e t. hatfield. p retoria0083 c hequesto a cco m p a n ym e m b e rsh ip lo rm june 1988 vol 3, no 2,1 20 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) guest editorial special edition: shoulder injuries in sport the shoulder was regarded as the “forgotten joint” in orthopaedic circles until recently. there has been, however, an “explosion” o f interest in the shoulder over the past few years the biomechanics and pathology o f shoulder con­ ditions have been well researched recently and has re­ sulted in a thorough understanding of effective treat­ ment modalities. this is reflected in an excellent arti­ cle on shoulder rehabilitation by ms gisela lauterbach. the advent o f shoulder arthroscopy has made an in­ valuable contribution to our understanding o f the nor­ mal and pathological anatomy. arthroscopic surgical techniques have advanced to a level where they do not only compete with the open surgical procedures, but have becom e the methods o f choice, especially when caring for the shoulder o f the young athlete. it is generally accepted in 1994 that a knee surgeon would perform a larger proportion o f procedures arth roscopically — the same is fast applying to the shoulder. it is therefore appropriate that we wrote a short arti­ cle on “the role o f arthroscopy in shoulder problems o f the athlete". an article on “acute shoulder injuries in the athlete” is a summary o f the more comm only encountered in­ juries and the treatment thereof. the most common shoulder problem (in athletes and the non-athletic population alike) is that o f chronic ro­ tator cuff pathology and a separate article deals with this. we trust that this shoulder edition will contribute to effective care o f the shoulders o f our athletes jf de beer mbchb, m med (o rth o p ) sa journal of sports medicine november 1994 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the south african journal of sports medicine volume 1 number 2 november 1994 guest editor dr j f de beer editorial board dr m p schwellnus university o f cape town dr m e moolla private practitioner durban dr a venter private practitioner bloemfontein dr p de jager private practitioner pretoria dr j skowno private practitioner johannesburg dr i surve private practitioner cape town dr p schwartz private practitioner port elizabeth prof g strydom potchefstroom university prof r stretch university of fort hare mrs j morton private physiotherapist durban mr d rehbock podiatrist johannesburg international advisory board lyle j michell associate clinical professor of orthopaedic surgery boston, usa chester r kyle research director, sports equipment research associates california, usa prof hc wildor hollman president des deutschen sportarziebundes koln, west germany howard j green professor, department of kinesiology ontario, canada george a brooks professor, department of physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke associate professor, biology department, university of colorado colorado, usa contents editorial j f de beer 1 forthcoming conferences 3 acute shoulder injuries in the athlete j f de beer m a de beer m p schwellnus 5 rotator cuff impingement syndrome in athletes m p schwellnus j f de beer m a de beer 12 the role of arthroscopy in shoulder problems of the athlete m a de beer j f de beer 18 rehabilitation of the athlete’s shoulder g lauterbach 19 a survey — anabolic androgenic steroids used by competitive bodybuilders in south africa s d titlestad m / lambert m p schwellnus 24 a profile of biokinetic services in south africa from 1988-1991 m f coetsee 29 the editor the sooth african sports medicine association po box 38567, p production andrew thomas publishing glenbarr publishers cc dunkeld 2196 tel: (o il) 442-9759 fax; (o il) 880-7898 cover sponsored the views expressed in individual articles are the personal views o f the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent o f the publishers. 'inelands 7430 by ciba-geigy advertising marika de waal/andrew thomas reproduction: output repro printing: hortors 2 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) forthcoming conferences national march 22-24, 1995. sasm a congress, elangeni hotel, durban. professional sports care through unity. a ll correspondence and requests to the confer­ ence organizers: mckenzie dickerson international, po box 4272, rivonia, 2128. tel: (o il) 402-3240/53/ 57. fax: (o il) 402-0164. june 19-22. international rugby medical and sports traumatological congress, sun city. for further information contact the venue coordinator, rugby world cup 1995. international rugby medical and sports traumatological congress, po box 99, newlands 7725. tel: (021) 685-3038. fax: (021) 685-6771. july 20-23, 1995. icpfar symposium 1995, the in­ te rnatio nal council for physical fitness a n d activity research, ltala game reserve, northern natal. abstracts should be submitted before january 15, 1995. for further details contact prof m f coetsee, department human movement science, uni­ versity o f zululand, private bag x1001, kwa dlangez wa 3886. tel: (0351) 93911 ext 235. fax: (0351) 93911. international april 5-7, 1995. conference on nutrition a n d physical activity, to optimize performance a n d well-being. the ritz-carlton, buckhead, atlan­ ta, georgia, usa. contact ms lili c merritt, internation­ al life science institute, 1126 sixteenth street, nw, washington, dc 20036, usa. tel: 202 659 0074. fax: 202 659 3859. may 21-25, 1995. first world forum o n physi­ cal activity a n d sport, quebec, canada. con­ tact: world forum on physical activity and sport, 2 olace quebec, suite 510, quebec city, quebec, cana­ da g1r 2b5. tel: (418) 648-6000. fax: (418) 648-0404. may 23-27, 1995. 10th international symposi­ um on ad apted physical activity. contact 10th isapa secretariat, the norwegian university o f sport and physical education, department o f information, postboks 40, kringsja, n-0807, oslo, norway. may 27-30, 1995. the eleventh international jerusalem symposium on sports injuries, dan panoram a, te l aviv, is r a e l contact: con­ gress secretariat, dan knassim ltd., po box 57005, tel aviv 61570, israel. tel: (972) 3 562 6470. fax: (972) 3 561 2303. june 1997. international association o f sports information congress, 10th scientif­ ic congress, paris. contact: mr a poncet, comite d’organisation, 11 avenue du tremblay, 75012 paris, france. tel: 33 1 43 74 11 21 email fra 7501 @ cr1 uc. unicaen. fr. august 25-26 1995. f1su/cesu conference, fukuoka, japan. sport and man: creating a new vi­ sion. contact: the organizing committee for the universiade 1995, fukuoka. cesu conference planning section, 6-1 tenjin 2-chome, chuo-ku, fukuoka city 810, japan. tel: 81 92 733 5212. fax: 81 92 733 5290. september 14-17, 1995. the xith fina world sports medicine congress, athens hilton, greece. contact public relations centre, helen haly vides, 102 michalakopoulou street, 115 28 athens, greece. tel: (301) 775 6336 or 777 1056. fax: (301) 771 1289. letters to the editor r e a d e rs ' le tte r s c o n c e r n in g a r tic le s in th e j o u r n a l a re in v ite d , a n d w ill b e f o r w a r d e d to o u r e d ito r s f o r c o n s id e r a tio n f o r p u b lic a tio n . p le a s e p o s t to: g len b a rr publishers c .c . 25 bom pas r o ad dunkeld 2196 sa journal of sports medicine november 1994 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sixth south african sports medicine association congress march 22-24 1995 — elangeni hotel, durban professional sports care through unity an international congress to unite all professionals active in sports medical care in south africa. themes of symposia and workshops: exercise science, sports medicine, sports physiology, physiotherapy, sports podiatry and biokinetics. international experts in sports medicine presenting papers. enquiry form fax back to: mckenzie dickerson fax: (o i l) 402-0164 tel: (o i l) 402-3240 □ i am interested in presenting a free paper. please send me an abstract form. □ i am interested in exhibiting at the congress. □ i am interested in attending the 3 day congress. please send me a registration form. name ...................................................................... surname ................................................................. m r ....... m r s ....... miss ....... d r ....... p r o f ...... position ................................................................... company/ university etc ......................................... postal address ........................................................ sports medicine exhibition for products and techniques to be shown to a highly selective target audience. t e l:.................................fax: press release the sixth south african sports medicine association congress will be held at the elangeni hotel, durban be­ tween 22-24 march 1995. the theme thoughout the congress o f “ professional sports care through unity” , will encompass discus­ sions o f sports medicine areas over the three days. these will include nutrition, sports medicine and inju­ ries, exercise science, physiotherapy, psychology, bioki­ netics and sports podiatry. areas that compliment and have association will be dealt with in joint workshops. s om e combinations are sports medicine/physiotherapy, exercise science/ bi­ okinetics and physiotherapy/biokinetics. various symposia on the above subjects will be avail­ able each day in three different venues, with two ses­ sions each morning and afternoon. free communica­ tion consisting o f presented papers on relevant topics will be held immediately after morning and afternoon tea every day. interested parties can contact the num­ bers below for an abstract form. the visiting speakers will include: dr louis burke — nutrition, the competitive edge. prof claude bouchard — muscles, performance and genes. mr craig purdam — rehabilitation o f ankle injuries in sport. dr ken crighton — tibial stress fractures: update on diagnosis and management. titles cover a broad spectrum o f topics such as mus­ cle injury and disease in sport, difficult hamstring in­ juries in sport, exercise, infection and immunity, isoki­ netic dynanometry, drugs in sport. conference registration will commence on tuesday march 21 at the elangeni hotel, with a w elcom e cock­ tail function that evening. on each o f the congress mornings, a sporting activity will be organised during the three day period. it is hoped that the delegate congress package cost will be kept to the 1993 price charged in cape town. special rates for group airfares, accommodation and car hire will be available to congress delegates. in conjunction with the congress, will be the largest and most exciting sports medicine exhibition to date. new products and techniques, plus a variety o f excit­ ing material will be on display. stand space is still avail­ able to any companies who wish to exhibit to a highly selective target audience. for further information contact sue or val — mckenzie dickerson int. tel: (o il) 402-3240. fax: (o il) 402-0164. 4 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) acute shoulder injuries in the athlete jf de beer mbchb m med (orthop)f ma de beer mbchb m med (orthop)* mp schwellnus mbbch msc (med) md facsm** introduction the aim o f this article is to discuss som e o f the more common acute injuries o f the shoulder complex. the injuries in each area will be discussed with respect to the mechanism o f injury, clinical diagnosis, special in­ vestigations and management. the rehabilitation o f acute injuries as well as the management o f overuse injuries will be discussed in another paper in this journal. sternoclavicular (sc) joint dislocation injuries to this joint are rare. the main acute injury to consider in the sc joint is dislocation. acute disloca­ tion o f the sc joint can be either anterior or posterior, with the anterior type being the most common, and for­ tunately the most benign. anterior dislocation the mechanism o f anterior sc dislocation is either from forces transmitted from the hand or a direct blow to the shoulder. the pathological feature that is o f importance is tear­ ing o f the joint capsule and costo-davicular ligam ent this may be a problem as it can result in a mechanical block and obstruct attempts at reduction. the clinical features are acute pain, swelling and de­ formity o f the medial end o f the clavicle. overhead or rotational movement o f the arm can cause grating, clicking and popping. this condition must be distin­ guished from a proximal clavicular fracture by x-rays. due to overlying shadows this is a difficult area to dis­ tinguish detail on x-rays and specialized views, tom o­ grams and computerized tomography (ct) scans are often needed. the condition is managed by achieving reduction as follows; the arm is pulled in abduction and the prox­ imal clavicle is manipulated to achieve reduction. the reduction is often difficult to hold but surgery for acute anterior dislocation is seldom indicated as it carries a high risk due to the proximity o f such vital structures as the large vessels. moreover, the chronically dislocat­ ed sc joint is usually compatible with good painless t leeuwendal medi-clinic, 3 derwent road, tamboers kloof, 8001. tel: (021) 23-4040. * jacamnda hospital, suite 3, 213 middelberg st, muck leneuk, 0181, pretoria. tel: (012) 343-0296. * * sports medicine, m r c /u c t bioenergetics o f exer­ cise research. unit, department o f physiology, university o f cape town medical school, observatory, 7925. tel: (021) 406-6504. function. the long term complications are that the athlete may notice aching, swelling, clicking or popping in that area. resection o f the proximal portion o f the clavicle may be required, with or without stabilization for the rare case. it must be stressed again that surgical interven­ tion for acute or chronic cases should be the exception. posterior (retrosternal) dislocation the mechanism o f injury is similar to that described for anterior dislocation, except that the direction o f the forces are different. the clinical presentation o f posterior dislocation is classical and requires immediate intervention. impor­ tant retrosternal structures such as the trachea and the great vessels are compressed and this may be life threatening. classical symptoms are dysphagia, snort­ ing type o f breathing and neurovascular symptoms in the upper extremity. the management is immediate reduction (anaesthe­ sia might be required) by the following method: the patient lies supine with a sandbag or equivalent be­ tween the two scapulae. the arm is abducted and ex­ tended while traction is applied. the clavicle may have to be grasped with a towel clip and then manoeuvered up and forward to achieve reduction. fractured clavicle the most common acute injury to the clavicle is a frac­ ture. the mechanism o f the injury is a fall on the out­ stretched arm. the most comm on site is the middle third o f the shaft the distal fragment is pulled down by the weight o f the shoulder girdle while the proximal fragment is held in place by the trapezium and sternomastoid mus­ cle. there may be a central fragment. the diagnosis is made clinically and confirmed on x-ray examination. the management is mostly conser­ vative. it is not possible or essential to achieve good reduction but the position may be improved by pull­ ing both shoulders backwards. a figure o f eight band­ age could be used to hold the position but it is only effective in children, not in adults. it is m ore important to support the limb with a sling for 3 weeks for pain. mobilization o f the fingers, wrist and elbow should be­ gin early. most fractures o f the clavicle will unite, usually resulting in mal-union which is compatible with normal function. the patient is left with a lump in the area which may get smaller with time, and a slightly “short­ ened" shoulder. fractures o f the clavicle in children have excellent remodelling potential, but this does not apply to adults to nearly the same extent. sa journal of sports medicine november 1994 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) in rare instances reduction and internal fixation of clavicle fractures are indicated. these are: i) severely displaced fracture fragments (with the skin being endangered due to pressure from the under­ lying fragments) ii) for severe pain hi) when multiple injuries have been sustained iv) if early function is critical v) cosmetic considerations a c r o m io c la v ic u la r (ac) joint sprain mechanism o f injury the most common mechanism is a fall o ra direct blow to the top o f the shoulder.1 the force is directed down­ wards and medially. this results in damage to the sup­ porting structures. th e magnitude o f the forcewih de termine which structures are damaged and thus the severity o f the injury. the w e a k e s t structures and he first to be damaged are the ac joint capsule and the ac ligament. with progressive increase in the magni­ tude of the force the coracoclavicular ligaments are damaged and rarely the coracoid process is fractured. there are other rarer mechanisms of injury. these are: — a direct lateral blow to the shoulder causing mtra articular damage but no ligament disruption — a force that is directed posteriorly which damages capsular ligaments, muscles and the trapezoid liga­ ment alone ____ — a fall on the outstretched arm which drives the hu­ merus into the acromion damaging the capsular structures but not affecting the coracoclavicular liga­ ments classification . . . a classification of acute acromioclavicular injuries (rockwood) is listed in table 1. types 1, 11 and iii are by far the most common injuries. clinical features clinically, athletes present with a history o f acute trau­ ma to the top of the shoulder followed by varying degrees of pain, deformity and loss of function (typi­ cally unable to abduct the arm). in type 1 injuries there is pain and tenderness over the ac joint. this may be the only finding or mild swell­ ing and loss of abduction may also be present. in type 11 and 111 injuries there is more severe pain swelling and loss of function. however, associated defor­ mity differentiates these from type 1 injuries. in type iv injuries (posterior displacement of the distal clavicle) there is more pain. clinically, the displacement can be best appreciated by looking from above the shoulder. type v injury is an exacerbation of the type 111 injury in which the upper extremity is grossly drooping lower than the normal side. pain is also more severe than in type 111. type vi injury is due to an abduction force to the up­ per extremity and the distal clavicle is displaced inferior to the acromion process. the superior aspect of the r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) shoulder therefore has a flat appearance. this is ex tremely rare. special investigations the following x-rays may be useful in the diagnosis of ac joint dislocation. the routine a p view often demon­ strates the ac joint adequately. a better view is the zanca ac joint view. this is an a p view which is tilted 15° upwards and centred on the ac joint to distinguish between type ii and iii injuries, stress views can be done; weights are strapped to both wrists in the standing posi­ tion and the ac joint views are taken o f both shoulders if the coracoclavicular distance is increased by more than 50% compared to the normal side it represents torn coracoclavicular ligam ents if a posterior disloca­ tion is suspected the axillary view is useful as a diag­ nostic investigation. treatment type i injuries the treatment o f these injuries is symptomatic. a sling may be necessary for 7-10 days rehabilitation should commence as soon as possible and should emphasize strengthening o f the trapezium and deltoid muscle groups return to sport can occur as soon as pain allows type ii injuries the treatment o f type ii injuries is also symptomatic although a slightly more aggressive approach is advo­ cated. the sling could be worn for 10-14 days for pain relief. a well designed rehabilitation programme is again important. type iii injuries there is controversy in the literature on the manage­ ment o f type 111 injuries. the two approaches are either conservative (closed) or surgical (open). conservative management (“expert neglect”) will lead to a chroni­ cally dislocated joint which can be compatible with nor­ mal painless function. in the young overhead athlete it is probably best to do early open surgery: reduce the acromioclavicular joint and repair the ligaments, in­ cluding the tom periosteal tube and delto-trapezius fas­ cia. if the injury was left untreated and resulted in a chronically painful instability a late reconstruction with excision o f the distal end o f the clavicle can be done successfully (weaver-dunn procedure). types iv, v and vi injuries the treatment is usually surgical: open reduction and repair o f soft tissue, including the delto-trapezius fas­ cia, acromioclavicular ligament and coracoclavicular ligaments the authors prefer immobilization of the re­ pair using an absorbable sling o f pds tape from the clavicle around the coracoid. glenohumeral joint instability classification glenohumeral instability can be classified accordina to:2’3 m leader of the p a c k when you need pain-killing power to get there first. o ru * g e t s t h e r e firs r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) — the degree o f instability (subluxation, dislocation) __the circumstances o f the instability (acute, chronic, recurrent or voluntary) — the aetiology (traumatic, non-traumatic) — the direction o f the instability (anterior, posterior, multidirectional) in this article acute glenohumeral instability will be discussed. acute anterior glenohumeral dislocation anatom y the shoulder provides more mobility than stability ana is therefore prone to instability. the main anatomical structures that prevent anterior displacement o f the hu_ meral head are the glenoid labrum, the long head of the biceps tendon, subscapularis and the glenohumeral ligaments (the inferior ligament is the most important). the rotator cuff muscles also provide an important mechanism for stabilizing the humerus because they contract and pull the humeral head against the glenoid. mechanism o f injury acute anterior dislocation can occur when one or more o f the anterior stabilizers o f the shoulder are stretched or disrupted. the forces that may cause this disruption may be direct (applied to the posterior aspect o f the humeral head) or indirect (a movement associated with vigorous hyperextension, abduction and/or external ro­ tation). the latter mechanism is common in sports par­ ticipation. . . . . the magnitude o f the force that is applied will de­ termine the extent o f damage. the damage may be only an anterior capsular sprain or there may be sub­ luxation or dislocation. the stability o f the shoulder is challenged in any sport where the shoulder is active in extension, abduction or external rotation. pathology , , , . . displacement o f the humeral head from the glenoid cavity results in injury to the joint capsule, glenoid labrum, humerus, nerves, blood vessels and the rota­ tor cuff. , . . . . . the joint capsule may be stretched, tom (more likely in older people) or avulsed from its attachment to the glenoid (younger people) — the so-called bankart le­ sion. tears o f the glenoid labrum, especially the anterior labrum can occur as part o f the bankart lesioa superior labral tears, involving the biceps anchor can occur (slap lesions). fractures of the greater tuberosity can occur. i he size o f the fragment, displacement o f the fragment and site o f the fracture are important to consider. if healing takes place with a fragment in a displaced position impinge­ ment can result. fragments displaced > 5mm should be manaaed by open reduction and internal fixation. large fragments (> 2 5 % o f the head) should be managed by open reduction and internal fixation. im­ paction o f the humeral head against the anterior gle­ noid lip can cause fractures of the posterolateral hume­ ral articular surface (hill-sacks lesion). this results in loss o f joint congruity and can result in recurrent in­ stability. . , . . . the brachial plexus is located antero-infero-medial to the glenohumeral joint damage may therefore occur to this structure. the most common nerve that is dam­ aged is the axillary nerve (5-33% o f cases). both sen­ sory (sergeant stripe area) and motor (deltoid) function must be assessed before and after reduction o f the dis­ located shoulder. persistent neurological deficits must be assessed by emg. the nerve injury is usually a neuropraxia that spontaneously improves in a sixmonth period. . the axillary artery lies in close proximity to the brachial plexus and may also be damaged in anterior dislocation. the pathology may be an intimal tear, lacer­ ation, occlusion, branch avulsion or a complete rupture. the rotator cuff may also be torn in anterior disloca­ tion. it may be difficult to assess the rotator cuff initial­ ly but two useful tests are isometric strength in abduc­ tion and external rotation. subscapularis may be torn or avulsed; the important “ lift-off test’ will indicate this. rotator cuff tears are more common in older people. classification o f anterior dislocation the following types o f anterior glenohumeral disloca­ tion have been described according to the site o f the humeral head. . — subcoracoid: this is the commonest type in athletes and is characterized by anterior displacement o f the humeral head so that it lies inferior to the coracoid process. — subglenoid: this is the second most common type and here the humeral head lies anterior but inferior to the glenoid fossa. — subclavicular. this is rare and here the humerus lies medial to the coracoid process and inferior to the lower border o f the clavicle. — luxatio erecta: in this condition the humeral head is dislocated anteriorly but the arm is fixed in a po­ sition o f complete elevation. — lntrathoracic in this type the humeral head is driven between the ribs into the thoracic cavity. diagnosis . the athlete will present with pain and loss of function after an acute precipitating event the classical history o f the mechanism o f injury can be obtained. on exami­ nation the shoulder is held in slight abduction and the i/ottanen s&lqq diclophenac sodium 1 0 0 mg mw_______ __ pasl '/« wiisenach 93065 d'dophenwcsodium womg 8 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) athlete is unable to adduct, abduct or rotate the shoul­ der. the lateral contour o f the shoulder may be flat­ tened and the humeral head may be palpated below the coracoid process the physical examination should also include an as­ sessment o f the possible neurological and vascular complications o f anterior shoulder dislocation. the diagnosis should be confirmed by x-rays two views at right angles to each other should be taken. these can be an anteroposterior view, lateral view or an axillary view. radiographs can indicate the type o f dislocation as well as any associated fractures management the immediate management is to reduce the dislocated shoulder. gentle reduction may be attempted on the field if the diagnosis is obvious early reduction has the following advantages less muscle spasm to overcome, less risk o f damaging neurovascular structures and minimizes damage to the humeral articular surface. reduction can be achieved by a number o f methods the principle that is to be followed is that o f applying traction to the arm in the abducted and flexed positions. the methods o f reduction are briefly as follows: lying supine on the bed with traction applied in 30° abduction while countertraction is applied (h iddo cratic method) — lying supine with the elbow flexed. traction is ap­ plied, the arm is slightly externally rotated and then internally rotated while adducted (kochers method) — lying prone on the bed with the injured arm hang­ ing down over the side. traction may be applied in a downward fashion. immediately after reduction the athlete should be re­ assessed clinically and with x-rays. it is important to re-assess the neurovascular status as well as the integrity of the rotator cuff. with the development of arthroscopic shoulder surgery the treatment is more aggressive. the younger the athlete, the more important early stabili­ zation becomes. the reason for this is the high rate of recurrent instability in young athletes after the first dis­ location: in the 20-year old recurrence can be as high as 100% and for any athlete playing contact sport ± in traumatic anterior dislocations the most important features of the post reduction management are im m o­ bilization and rehabilitation. immobilization is done in the position o f relaxed anterior structures (adduction, internal rotation) and is best achieved by a sling. the duration o f immobilization is usually 3 weeks. the rehabilitation will be discussed in another article in this journal but the principles are to strengthen the anterior supporting structures (subscapularis inferior glenohumeral ligament) and the external rotators (infra­ spinatus). complications the complications o f acute anterior glenohumeral dis­ location are: — recurrent anterior instability is a very common complication — neurovascular damage associated injuries to other structures (rotator cuff and biceps tendon) joint stiffness after dislocation (caused by prolonqed immobilization or unreduced dislocation) acute posterior glenohumeral dislocation posterior glenohumeral dislocation is much less com ­ mon in the athlete. the incidence ranges from 1 to 4% o f all acute dislocations the sports in which this injury has been described are: skiing, throwing, football, vol­ leyball, gymnastics racquet ball, wrestling and tennis mechanism o f the injury the mechanisms o f an acute traumatic injury can be— a severe blow to the front o f the shoulder in inter­ nal rotation and adduction — a fall on the outstretched hand with the elbow ex­ tended and the humerus in internal rotation other more comm on non-athletic mechanisms o f in jury are falls during seizures electric shocks motor ve­ hicle accidents industrial injuries and congenital ab­ normalities that predispose to posterior dislocation (qle noid dysplasia). clinical diagnosis this is an injury that is often missed and would there­ fore only be diagnosed by carefully paying attention to detail. the mechanism o f injury is important to estab­ lish and careful questioning is required the athlete may also complain o f severe pain (m ore than in an anterior dislocation). the features on clinical examination are: — locking o f the shoulder in internal rotation and ad­ duction (no external rotation is possible) — abnormally prominent coracoid process flattening o f the anterior deltoid prominent head o f the humerus posteriorly posterior angulation o f the long axis o f the arm — lack o f either active or passive external rotation or abduction o f the affected arm a high index o f suspicion is required to make the di­ agnosis clinically special investigations it is most important to obtain the correct x-ray views if the diagnosis is to be made. the view that will con­ firm the diagnosis is an axillary view or trans-scapular view. management the challenge in this condition is to make the diagnosis as early as possible. once the diagnosis is made the treatment is early reduction. this is best done by an experienced orthopaedic surgeon. the method is to ap­ ply gentle traction to the arm in adduction, applying gentle anterior pressure to the humeral head and as pressure is maintained to slowly externally rotate the arm. general anaesthesia is usually required. maintenance o f reduction is achieved by holding the arm in external rotation and slight abduction with a plaster jacket for 3 weeks active rehabilitative exercises are carried out after this until function is regained. acute traumatic subacromial bursitis this injury is caused by a sudden impact force which drives the humerus against the acromion. the usual po­ sition producing this injury is a fell on the outstretched sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) hand with the arm in slight abduction. the clinical pre­ sentation is severe pain and loss o f function. haemor­ rhage occurs in the bursa and blood can be aspirated from the bursa. pain can be relieved by instilling local anaesthetic into the bursa. the treatment is conservative consisting o f rest fol­ lowed by mobilization and rehabilitation. recovery re­ quires 6-8 weeks o f treatment.11 this condition is diffi­ cult to distinguish from acute rotator cuff rupture and will often require ultra sonography or arthrogram to ex­ clude the latter. fractures of the scapula fractures of the scapula are uncommon in athletes but have been described in football, ice hockey and riding. the mechanism of injury is usually a direct crushing force which fractures the body, neck, acromion or cora­ coid process rarely the injury may be associated with fractured ribs or clavicle, or dislocation of the sterno­ clavicular joint or ac joint. on examination the athlete will complain of painful shoulder movements but generally the movements will still be possible. if there are associated respiratory symptoms a thoracic injury must be excluded. x-rays are usually necessary to confirm the diagnosis. in cer­ tain scapular fractures there might be pseudo-paralysis of the rotator cuff muscles mimicking a rotator cuff tear. the management is conservative. a sling can be worn for comfort and active exercises o f the shoulder, elbow and hand should be encouraged from as early as possible. fractures o f the scapula may lead to com­ partment syndrome o f the supraor the infra spinatus muscles: this complication should be recognized early and dealt with surgically. more serious scapular fractures that require operative intervention are usually due to high impact injuries (road accidents) and are not in the scope o f this paper. acute soft tissue injuries of the shoulder acute rotator cuff tear tears of the rotator cuff muscles are rare in younger individuals, but should always be considered in the older patient with a shoulder injury (40 years and older). a tear of the supraspinatus is the most common and can result from a direct fall on to the shoulder or in­ direct forces on the arm. larger tears can extend pos­ teriorly to involve the infraspinatus and teres minor. tears o f the subscapularis tendon are rare and should specifically be considered in the older sportsman where the arm was forced into abduction and external rotation. rotator cuff tears present clinically as follows: — severe pain not responding to conservative treat­ ment modalities — weakness of elevation. weak supraspinatus test (‘uobe’s thumb down” test) — weak “ lift-off’ test (subscapularis tears). — weak external rotation (infraspinatus/teres minor tears) confirmation o f the tears is by ultra-sound, arthrogram or mr1. traumatic tears of the rotator cuff should be repaired surgically as soon as possible. partial thickness tears occur commonly and can be diagnosed most accurately with the arthroscope. rupture o f the deltoid muscle rupture o f the deltoid is infrequent but has been de­ scribed in handball and volleyball players. it may occur as a result o f an acute blow to the arm or as a result o f overuse. it usually affects only a part o f the muscle. the diagnosis is made on clinical signs and the treat­ ment is conservative followed by active rehabilitation. rupture o f the pectoralis major muscle the pectoralis major can be injured (partial or complete rupture) if excessive loads are applied to the shoulder in internal rotation. sports in which this has been de­ scribed are weight lifting (bench press), wrestling, shot put, discus and javelin. the clinical signs are pain at the insertion o f pec­ toralis on the humerus, swelling, bruising and loss of function. the management is conservative except in cases o f total rupture where surgical repair is indicated. active rehabilitation post injury is encouraged. rupture o f the long head of biceps rupture of the long head o f the biceps is seen in older athletes (40-50 years). this is usually secondary to some degenerative change in the tendon, and is associated with rotator cuff tears. the sports where this has been described are: gymnastics, tennis, badminton, wrestling, weight lifting, javelin and oarsmen. the clinical features are pain over the anterior aspect o f the shoulder, swelling (which is prominent on the an­ terior aspect o f the humerus on contraction of the mus­ cle) and loss o f function (weakness). management is conservative in older athletes but sur­ gical repair is indicated in the competitive or younger athlete (tenodesis o f the tendon in its groove). active rehabilitation post injury or surgery is indicated. rupture of the triceps muscle tendon the tendon of triceps may rupture during sport by falls on the flexed arm or in throwing. the clinical features are pain on the posterior aspect of the elbow and some­ times a gap can be felt. loss of function is characterized by pain on elbow extension. treatment is conservative unless there is a total rupture in a young competitive athlete. voltaren (jt50 diclophenac sodium so mg w.™ 10 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table i the modified classification is as follows: ty p e 1 sprain o f acromioclavicular ligament acromioclavicular joint intact coracoclavicular ligaments intact deltoid and trapezius muscles intact t y p e ii acromioclavicular joint is disrupted acromioclavicular joint wider; may be a slight ver tical separation when compared with the normal shoulder sprain o f the coracoclavicular ligaments coracoclavicular interspace might be slightly increased deltoid and trapezius muscles intact ty p e iii acromioclavicular ligaments disrupted acromioclavicular joint dislocated and the shoul­ der complex displaced inferiorly coracoclavicular ligaments disrupted coracoclavicular interspace greater than the nor­ mal shoulder (i.e. 25 to 100 per cent greater than in the normal shoulder) deltoid and trapezius muscles usually detached from the distal end o f the clavicle in children, a pseudodislocation o f the acromi­ oclavicular joint occurs the coracoclavicular ligaments remain intact to the intact periosteal tube, and the clavicle is displaced out of the peri­ osteal tube. t y p e iv acromioclavicular ligaments disrupted acromioclavicular joint dislocated and clavicle anatomically displaced posteriorly into or through the trapezius muscle coracoclavicular ligaments completely disrupted coracoclavicular space may be displaced, but may appear to be same as the normal shoulder deltoid and trapezius muscles detached from the distal clavicle t y p e v acromioclavicular ligaments disrupted coracoclavicular ligaments disrupted acromioclavicular joint dislocated and gross dis­ parity between the clavicle and the scapula (i.e., 100 to 300 per cent greater than the normal shoulder) deltoid and trapezius muscles detached from the distal half o f the clavicle typ e vi acromioclavicular ligaments disrupted coracoclavicular ligaments disrupted acromioclavicular joint dislocated and clavicle dis­ placed inferior to the acromion or the coracoid process coracoclavicular interspace reversed with the clavi­ c le being inferior to the acromion or the coracoid deltoid and trapezius muscles are detached from the distal clavicle fractures of the proximal humerus fractures o f the proximal humerus can occur during sports participation. it is more common in the older ath­ lete and is usually the result of a fell on the outstretched arm or direct trauma to the shoulder. it has been described in contact sports such as football, rugby, ski­ ing and riding. the most common site o f fracture is the neck o f the humerus avulsion fractures o f the greater tuberosity (supraspinatus insertion) often occurs with shoulder dislocation. the lesser tuberosity (sub scapularis tendon insertion) can be avulsed in posteri­ or dislocation. the clinical presentation is pain, swelling and loss o f function. adequate and comprehensive x-rays are most important to establish the extent and type o f in­ jury. the “trauma series" o f x-rays should include a true ap, scapular lateral and "trauma axillary” view. in general the management is conservative (sling) with early mobilization being very important surgical treatment is indicated in severe angulation ( > 40°), in epiphyseal plate fractures and displaced fractures of the greater tuberosity (associated with tears in the rotator cuff). more complex fractures o f the proximal humer­ us involving multiple parts o f the humeral head usual­ ly require surgical reconstruction by a shoulder surgeon. references 1. wickiewicz tl: acromioclavicular and sternoclavicular joint iniu lies. clin sports med 1983; 2 (2): 429-438. 2. matsen fa and zuckerman jd: anterior glenohumeral instabiutu clin sports med 1983; 2 (2): 319-338. 3 l̂ eers ^ and welstl rp: the shoulder in sports. orthop clin north am 1977; 8: 583-591. 4 ^ 9 8 ^ 2 ^ 2 ^ 3 9 ^ 5 4 ^ ̂ sholdder 61 atmetescun sports med further suggested reading: andrews jr and wilk kb the athletes shoulder. churchill livingstone, new york 1994. apley ag and solomon l: apley's system o f orthopaedics and frac tunes butterworth and co, (publisher) ltd, 1982, london. davies gj, gould ja and larson rl■ functional examination of the shoulder girdle. phys and sportsmed 1981; 9 (6): 82-104. jobe fw and bradley jp: the diagnosis and nonoperative treatment of shoulder injuries in athletes. cun sports med 19898 (3y 419-438. ' ^ e d 11982^ injured atmete' ijppincou' philadelphia, toronto, 2nd ma?9 9 2 j: skoulder lnjuries ^ sports' m pen publishers, rockville, peterson l and renstrom p: sports injuries: their prevention and treat­ ment. m duncan and g beaton (editors). juta and co ltd, 1986 johannesburg. rockwood and matson: the shoulder. w saunders, 1990. rosenom m and pederson eb: the significance o f the coracoclavicu­ lar ligament in experimental dislocation of the acromioclavicular joint acta orthop scand 1974; 45: 346-. samilson rl and prieto v: posterior dislocation o f the shoulder in ath­ letes. cun sports med 1983; 2 (2): 369-378. snyder sj: shoulder arthroscopy and related surgery. orthop cun north am 1993; january. q sa journal of sports medicine november 1994 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) rotator cuff impingement syndrome in athletes mp schwellnus mbbch msc (med) md facsm* jf de beer mbchb m med (orthop)t ma de beer mbchb m med (orthop)** introduction the most cx>mmon chronic shoulder injury in the athlete is the rotator cuff impingement syndrome. pain presenting in the shoulder joint as a result o f pathology in the rotator cuff represents a spectrum o f clinical con­ ditions which have been labelled as painful arc syn­ drome, rotator cuff tears, supraspinatus tendonitis and subacromial bursitis o f the shoulder.2 however, all these syndromes represent a spectrum o f diseases and can all probably best be described clinically by the term rotator cuff impingement syndrome. mechanism of injury there are two proposed mechanisms o f injury to the rotator cuff in the rotator cuff impingement syndrome. these have been termed the mechanical model and the vascular model. mechanical model this model, which was proposed in the early 1970’s, states that mechanical compression o f the soft tissues in the subacromial area is the principle mechanism o f injury.3 the basis for this compression is the approx­ imation o f the greater tuberosity o f the humerus to the coracoacromial arch specifically during elevation o f the arm. the exact site o f the impingement has been iden­ tified. initially it was thought that the impingement was on the lateral acromion but subsequent studies have shown that the predominant area o f impingement was the anterior part o f the acromion.4 the normal function o f the rotator cuff involves the movement o f soft tissues (rotator cuff tendons, capsule and biceps tendon) in the subacromial space (space bet­ ween the humeral head and the coracoacromial liga­ m ent) the predisposing factors to mechanical impinge­ ment can therefore be related to either narrowing o f the subacromial space, or abnormal movement o f tissue * sports medicine, m r c /u c t bioenergetics o f exercise research unit, department o f physiology university o f cape town medical school, observatory, 7925 teh (021) 406-6504 f leeuwendal medi-clinic, 3 derwent road, tamboers kloof, 8001, cape town. tel: (021) 23-4040. * * jacaranda hospital, suite 3, 213 middelberg st, muckleneuk, 0181, pretoria. tel: (012) 343-0296. through the subacromial space. th e factors that play a role in each o f these mechanisms will now be discussed. narrowing of the subacromial space this is probably the most important cause for impinge­ ment. th e size o f the subacromial space can be decreased by any o f the following mechanisms. type o f shoulder movement: the size o f the subacromial space does not remain con­ stant during shoulder m ovem ent elevation o f the arm, particularly in abduction and forward flexion, causes narrowing o f the subacromial space. this is aggravated if the arm is held in internal rotation during the move­ ment because the greater tuberosity o f the humerus then enters the canal. it has been shown that during forward flexion and internal rotation the distance bet­ ween the coracoid and the humerus is reduced to 6.7mm. this space must accommodate the articular c a rtila ge o f the hum eral head (2-3m m ), the subscapularis muscle (2-4mm), the joint capsule (l-2mm) and still leave room for m ovem ent small varia­ tion s in t h e ' an atom y m ay p red isp o se to impingement.5 weakness and/or fatigue o f the shoulder girdle muscles: during shoulder function the subacromial space may also decrease if there is excessive movement o f the humeral head (upwards movement). the rotator cuff muscles are responsible for approximation, stabilization and centralization o f the humeral head during shoulder movement. any weakness or fatigue o f these muscles can result in excessive movement o f the humeral head and therefore obliteration o f the subacromial space.6 pathology in the subacromial bursa: hypertrophy and fibrosis o f the subacromial bursa can result in obliteration o f the subacromial space.7 pathology o f the acromioclavicular (a c ) joint: degenerative lesions, thickening or separation o f the acromioclavicular joint have been described as associated factors in impingement syndrome.38 the mechanism by which ac joint pathology causes imp­ ingement is that it causes narrowing o f the subacromial space. acromion process: it has been postulated that variations in the shape, size, slope or thickness o f the acromion process can 12 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) predispose an individual to narrowing o f the subacromial space and therefore the impingement syndrome.49 in this regard the slope and thickness o f the acromion appears to play an important role. in par­ ticular, if the shape o f an acrom ion is one that angles down too far and forms a “ beak” on the end it causes narrowing o f the subacromial space.10 bigliani" has classified the acromion in three types: type i (flat), type 11 (curved) and type 111 (hooked). abnormal movement a. excessively frequent movement: it has been postulated that excessive repetitive m ove­ ment o f the shoulder in the elevated position can cause irritation and inflammation o f the rotator cuff. the resultant oedem a will cause swelling and therefore in­ crease the volume o f soft tissue in the subacromial space.12 in more chronic cases the inflammation pro­ gresses to fibrosis and calcification. a compromised blood flow to the area can also aggravate this process (see vascular m odel).13 b. abnormal type o f movement: there are specific movements that are related to rotator cuff impingement syndrome. these are all movements in which there is arm movement above the shoulder level. the sports in which this is a common movement are throwing (baseball, cricket), racquet sports and swimming. if overhead movements are associated with internal rotation o f the shoulder the risk o f impinge­ ment is greater. c. muscle weakness: impingement can occur due to relative weakness of the humeral head depressors. in swimmers and other over­ head athletes there is often an imbalance between the internal and external rotators o f the shoulder (the lat­ ter being weaker). attention to these muscles (infra­ spinatus and teres minor) as a cause o f secondary im­ pingement is mandatory. poor function o f the “scapular setting” muscles can be associated with secondary impingement. the peri scapular muscles (trapezium, rhomboids, levator scap­ ulae and serratus anterior) “position” the scapula to en­ able the rotator cuff to function properly. should this function be inadequate, the rotator cuff is fatigued and this leads to impingement. d. shoulder instability: instability (even minor or “ subtle” instability) is also an important cause o f secondary impingement. during elevation o f the arm the humeral head can sublux antero-superiorly, and cause impingement. the in­ stability obviously needs to be assessed and treated (often arthroscopically) for the impingement to be cured. vascular model the vascular model for rotator cuff pathology is based on findings o f the microvascular pattern o f the rotator cuff tendons during movement. th e classical descrip­ tion o f the avascular zone o f the supraspinatus and biceps tendon was reported in 1970.14 the rotator cuff tendons have a poor blood supply which predispose them to poor healing following repeated microtrauma. the blood supply to the supraspinatus tendon and the intracapsular portion o f the biceps tendon is decreased when the arm is in the adducted position (arm hanging at the side) due to the pressure o f the humeral head on the blood vessels. if the shoulder is abducted the vessels are filled.9 the mechanical model and the vascular model may compliment each other to explain the mechanism of impingement (mechanical irritation and poor healing). however, it has been stated that the area o f avascularity may have developed as a protective mechanism to prevent recur­ rent haemorrhage in an area which is susceptible to repeated microtrauma.7 pathology of rotator cuff impingement syndrome the pathology o f chronic lesions o f the rotator cuff can be regarded as a continuous process which ranges from irritation o f the soft tissues and ends in rupture o f the rotator cuff. most authors therefore adopt a process of staging lesions of the rotator cuff along this continuum. the most widely accepted staging is that o f neer.91517 clinical diagnosis and treatment o f the impingement syndrome is based on neer’s stages. the pathology of these stages will now be discussed. neer’s stage i (oedema and haemorrhage) this is the first stage o f rotator cuff impingement and is characterized by oedem a and haemorrhage in the rotator cuff.3 the site o f the injury can vary from be­ ing predominantly in the supraspinatus tendon (most common) or the biceps tendon (less common). it oc­ curs typically in the young athlete ( < 2 5 years) and is reversible if managed correctly. this is the predominant lesion seen in the young active sportsperson. neer’s stage ii (fibrosis) this stage is characterized by fibrosis in the rotator cuff and therefore reflects persistent inflammation usually as a result o f repeated irritation.3 the site o f fibrosis and thickening can be in the rotator cuff tendons (main­ ly supraspinatus), subacromial bursa or the long head o f biceps can also becom e involved. it is more common in the older age group (25-40 years) and is not necessarily reversible. neer’ stage iii (rotator cuff tears, biceps rupture) this stage o f the rotator cuff impingement syndrome is characterized by permanent changes in the tissues. these changes are ruptures o f the rotator cuff (partial or full) and ruptures o f the long head o f the biceps. neer’s stage iv (bony changes) specific examples o f bony changes that can occur are traction spurs in the coracoacromial ligament and on the ventral surface o f the acromion followed by erosion o f the anterior acromion.3 sa journal of sports medicine november 1994 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) neer’s stage v (cuff tear arthropathy) due to the chronic rotator cuff tear there is cartilaginous degeneration o f the glenohumeral joint. typically the patients that present with rotator cuff impingement syndrome (types 111, iv and v) are older ( > 4 0 years). the changes are also permanent unless treated surgically. although the same principles o f staging are used generally, other authors have used a four stage classification o f impingement syndrome. jobe’s classification o f rotator cuff impingement1-16 stage i this stage is characterized by oedem a and inflamma­ tion. there is temporary thickening o f the bursa and rotator cuff but no permanent defect. stage ii this stage is characterized by disruption o f fibres o f the rotator cuff but no actual tear. if allowed to heal without correct treatment there is a risk o f developing contrac­ tures in addition there is permanent thickening o f the bursa and rotator cuff with scar formation. stage iii this stage is characterized by permanent thickening and scar formation (as in stage 11) but there is a possi­ ble partial tear o f less than 1 cm. this tear refers to a tear greater than 1cm in the circumferential plane. stage iv in this stage there is permanent thickening o f the bur­ sa and the capsule, associated scarring and a tear in the rotator cuff which is greater than 1cm in the cir­ cumferential plane. in this classification the management is again bas­ ed on the stage o f the syndrome.16 in this paper the staging o f neer will be used unless indicated otherwise as this is the most widely accepted staging o f rotator cuff impingement syndrome. diagnosis of rotator cuff syndrome sym ptom s: although it is important to elicit the symptoms in order to establish the correct diagnosis it must be emphasiz­ ed that the history should also include thorough ques­ tioning on the mechanisms and possible causes o f the athletes’ shoulder com plaint this should include history o f the mechanism o f injury, training program, and equipment used. stage i the main presenting symptom in all stages is pain in the shoulder. however, the nature o f the pain may dif­ fer. in stage i the pain is often a dull ache only after the activity. the pain may be described as “tooth ache” like pain.15 this can then progress to pain experienc­ ed during activity which eventually interferes with the activity.15 a hallmark o f this pain is that it subsides on cessation or modification o f the activity. the pain may also manifest as night pain. there is no associated weakness o f muscles in stage 1 except that related to pain. in the overhead athlete the arm movement must be analyzed and note should be taken where in the movement the pain occurs, as this can help with the diagnosis, eg. in the baseball-pitcher, if the pain occurs in the “cocked” position it is more likely due to instability. if the pain occurs when the arm is overhead it is more than likely due to impingement, and so on. this pattern can be applied for all the dif­ ferent overhead sports stage ii the symptoms o f stage 11 are an extension o f those in stage 1. the pain is often more frequently encountered during the day and may be experienced during non­ sports activities such as reaching overhead. night pain is also m ore prominent. there may be complaints o f a slight limitation of movement or associated muscle weakness in stage 11. the hallmark o f stage 11 is that the disease process is no longer reversible with activity modification or cessation.3 stage iii the young competitive athlete rarely presents in this stage. there is usually a long history o f chronic pain and loss o f function. athletic activity is often not possi­ ble because o f the limitations o f pain and weakness the symptoms o f stiffness (due to loss o f range o f movement) and muscle weakness (abduction and ex­ ternal rotation) are prominent. the periods o f pain are prolonged and are particularly prominent at night the hallmarks o f this stage are the chronicity o f the disease and the permanent pathological changes signs it is important to elicit the clinical signs that will con­ form the correct diagnosis as well as identify the stage o f the disease. however, a thorough biomechanical ex­ amination o f the shoulder must include evaluation o f the range o f m ovem ent, m uscle strength and mechanism o f injury. stage i the most important clinical sign in the diagnosis o f this condition is a positive neer’s impingement sign.3 the diagnosis can be confirmed by a positive neer’s imp­ ingement test (injecting the subacromial space with 6-10ml local anaesthetic and repeating the impinge­ ment test). other clinical signs are:13 — palpable tenderness over the greater tuberosity of the humerus at the supraspinatus insertion — palpable tenderness along the anterior edge o f the acromion — painful abduction specifically between 60 and 120° (painful arc sign) — muscle weakness associated with abduction which disappears after injection o f local anaesthetic into the subacromial space — tenderness over the biceps tendon (biceps involve­ ment in stage 1 however, is rare and this finding is not common).17 14 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) stage ii the clinical signs o f stage 1 can all be demonstrated in stage 11. in addition there is: — limitation o f movement — the weakness is more pronounced (can however be normal following the injection o f local anaesthetic) — soft tissue crepitus — a catching sensation during abduction at approx­ imately 100° which is due to fibrosis and scarring. stage iii the findings on physical examination o f staqe iii a r e : 13.l5,l8 — limitation o f shoulder movement (active more than passive) — muscle atrophy (infraspinatus and supraspinatus) — biceps tendon lesions ranging from tenderness to rupture — acromioclavicular joint involvement (positive com­ pression test) — weakness o f shoulder musculature which persists after injection o f local anaesthetic into the subacromial space — positive clinical signs for rupture o f the rotator cuff muscles — sings o f shoulder instability may also be present special investigations x-rays good quality x-rays should be done including the following views: — true a p — supraspinatus outlet view — axillary view — a p 3 0 ° (caudal tilt) is optional — ac joint view is essential the x-ray findings in stage 1 are normal. the x-ray changes o f impingement syndrome typically lag behind the clinical course.15 however, causes o f underlying predisposing factors may be identified on x-rays (acromial shape and angle, ac joint pathology). there may be features noted on x-rays later in stage 11. these are cystic changes in the greater tuberosity of the humerus as seen best on the 10° ac view, osteophytes on the undersurface o f the acromion and, changes in the acromioclavicular joint. x-ray changes are most likely seen in stage 111. the abnormalities that must be identified are:915 — narrowing o f the subacromial space ( < 5mm space indicates a rotator cuff tear) — superior migration o f the humeral head — erosion o f the acromion sclerosis and osteophyte formation on the acromion and greater tuberosity o f the humerus x-rays must also be evaluated for the presence of underlying predisposing factors to impingement and causes o f narrowed subacromial space should be identified. ultrasonography ultrasound is cost-effective and accurate to detect tears o f the rotator cuff but is operator-dependant. it is also very helpful to show calcific deposits in the cuff, biceps tendon pathology, subscapularis tears and coracoid impingement. arthrography double contrast arthrography o f the shoulder joint is a useful technique for the diagnosis o f rotator cuff tears with an accuracy o f 99%.19 communication o f contrast medium between the glenohumeral joint and the subacromial bursa indicates a complete tear o f the rotator cuff. it can be combined with cat scan (“ct ar­ thrography”). arthrography only indicates the presence, not the size o f a rotator cuff tear. magnetic resonance imaging (mri) mr1 is a very useful investigation to delineate exact pathology in the soft tissues (a shoulder dedicated coil must be used). it is therefore accurate in the diagnosis o f rotator cuff pathology. the major limitation is the tim e it takes and the expense involved, and should on­ ly be used in the exceptional case. arthroscopy of the shoulder joint this technique is rapidly becom ing the investigative procedure o f choice in rotator cuff impingement syn­ drome. it is very accurate for the identification o f rotator cuff pathology and has the added advantage that surgery m ay be perform ed at the sam e tim e.15 surgical procedures that can be done arthroscopically include bursectomy, acromioplasty, excision o f the lateral end o f the clavicle, rotator cuff debridement and stabilization procedures like anterior and posterior bankart repair and s l a p lesion repair. (the diagnosis and treatment o f the latter can in fact only be done arthroscopically). differential diagnosis the following conditions must be distinguished from impingement syndrome.13 — acute traumatic bursitis — shoulder instability syndromes (which may be associated with secondary impingement) — primary acromioclavicular pathology — cervical spine disease — glenohumeral arthritides — calcific tendonitis — frozen shoulder management of rotator cuff impingement syndrome stage i this stage o f the disease process is reversible and should therefore be managed correctly to avoid progres­ sion. the management is conservative and the princi­ ples o f conservative management are to diminish the in­ flammation, maximize shoulder function and to correct or modify the activity.18 the conservative management and rehabilitation will be addressed in a separate article. general principles it is important to note that rotator cuff impingement in the young athlete is often secondary to instability sa jogrnal of sports medicine november 1994 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) — the latter should then be addressed first. weakness o f the humeral head depressors (rotators) is also a com mon causative problem and specifically strengthening o f the external rotators (infra spinatus and teres minor) should be addressed. posterior capsular tightness is often an associated causative factor and stretching of the posterior capsule is mandatory. n on steroidal anti-inflammatory drugs a short course o f these drugs can be prescribed to d e cre a s e in fla m m atio n in this sta ge o f the disease.1315’20 subacromial cortisone injection although this is a comm on form o f therapy, frequent injections without caution increases the risk o f tendon rupture.21 in general no more than two or three cor­ tisone injections are recommended. the cortisone can be mixed into the solution when doing the im pinge­ ment (injection) test with local anaesthetic. surgical treatment (stage i) rarely athletes with stage i lesions are not successfully rehabilitated on conservative treatment although these athletes are a small minority, surgery may have to be considered if conservative treatment has failed (at least 6 months o f adequate conservative treatment must be allowed).13 the athlete must also be aware that athletic competition after surgery may be compromised (impor­ tant in the throwing athlete). surgical management should include a thorough arthroscopic evaluation o f the gleno humeral joint to exclude instability with secondary impingement and other pathology, follow­ ed by evaluation o f the sub-acromial space to confirm im pingem ent if bursectomy, excision o f the coraco acromial ligament and acromioplasty is decided upon it should preferably be done arthroscopically in the young athlete. stage ii conservative treatment the initial treatment for stage ii o f rotator cuff impinge­ ment syndrome is conservative. the type o f treatment is essentially the same as stage 1. differences in the con­ servative approach to stage 1 and ii are: — activity in stage 11 must be restricted more than in stage i (ie. only kicking in swimming, complete rest from throwing and limiting tennis shots to the forehand hitting against a wall) — medication use in stage 11 may be more prolonged — greater emphasis is placed on a range o f motion ex­ ercises in stage ii to prevent adhesive capsulitis — resistance exercises tend to be less intense in stage 11 to prevent overloading o f the rotator cuff surgical management o f stage ii surgical management is more common in stage ii than in stage 1. the main indication for surgery is failed con­ servative treatment (duration o f at least 6-12 months). other indications for surgery are i) permanent narrow­ ing o f the subacromial space for example if there is an abnormal angle o f the acromion and ii) associated in­ stability o f the shoulder which results in im pingement under these circumstances conservative treatment is likely to fail unless the underlying defect is corrected. surgical management should again include arthrosco­ pic evaluation and arthroscopic treatment as far as possible. stage iii the treatment of stage iii o f the rotator cuff im pinge­ ment syndrome is surgical.101315’22 surgery involves decompression, repair o f the rotator cuff and anterior acromioplasty. the outer part o f the clavicle and the acromioclavicular joint may also have to be resected as part o f the decompression. the tendency is to per­ form arthroscopy of the shoulder earlier and this is both as a diagnostic procedure as well as performing the surgery arthroscopically. prognosis there are no published controlled clinical trials on the conservative treatment of rotator cuff impingement syndrome.15 in one report on the outcome following surgical treatment for rotator cuff tears in athletic population, the results indicate pain relief post operatively in 76% of subjects, but only 32% o f the professional pitchers were able to return to the same level o f competition after surgery.22 references 1. jobe fw and jobe cm: painful athletic injuries of the shoulder. cun orthop and rel res 1983; 173: 117-124. 2. brunet me, haddad rj and porche eb: rotator cuff impingement syndrome in sports. phys sportsmed 1982; 10 (12): 86-94. 3. neer cs and welsh rp: the shoulder in sports. orthop clin north am 1977; 8: 583-591. 4. neer cs. impingement lesions. cun orthop 1983; 173: 70-77. 5. gerber c, terrier f and gam r: the role of the coracoid process in the chronic impingement syndrome. j bone joint surg (br) 1985; 67: 703-708. 6. pappas a, zwacke r and mccarthy c: rehabilitation of the pit­ ching shoulder. am j sports med 1985; 13: 223-235. 7. ciullo jv and steuens gg: the prevention and treatment of in­ juries to the shoulder in swimming. sports med 1989; 7: 182-204. 8. kessel l and watson m: the painful arc syndrome. j bone joint surg (br) 1977; 59: 166-172. 9. hawkins rj and hobeika pe: impingement syndrome in the athletic shoulder. cun sports med 1983; 2 (2); 391-404. 10. nash hl: rotator cuff damage: reexamining the causes and treatments. phys and sportsmed 1988; 16 (8): 12135. 11. bigliani lci: arthroscopic resection of the distal clavicle. or­ thopaedic cunics of north america 1993; 24: 133-141. 12. penny jn and welsh rp: shoulder impingement syndromes in athletes and their surgical management am j sports med 1981; 9 (1): 11-15. 13. hawkins rj and kenndy jc: impingement syndrome in athletes. am j sports med 1980; 8 (3): 151-158. 14. rathbun j and macnab 1: the microvascular pattern of the rotator cuff. j bone joint surg (br) 1970; 52: 540-553. 15. thein la: impingement syndrome and its conservative manage­ ment josft 1989; 11 (5); 183-191. 16. jobe fw and moynes dr: delineation of diagnostic criteria and a rehabilitation program for rotator cuff injuries. am j sports med 1982; 10 (6): 336-339. 17. ciullo jv: swimmer's shoulder. cun sports med 1986; 5 (1): 115-136. 18. simon er and hill ja: rotator cuff injuries: an update. jospt april 1989; 394-398. 19. newberg ah: the radiographic evaluation of shoulder and elbow pain in the athlete. clin sports med 1987; 6: 785-809. 20. richardson a: overuse syndromes in baseball, tennis, gymnastics and swimming. cun sports med 1983; 2: 379-389. 21. kennedy jc, hawkins r and krissoff wb: orthopaedic manifesta­ tions o f swimming. am j sports med 1978; 6 (6): 309-322. 22. tibone je, elrod b, jobe fw, kertan rk et al: surgical treatment o f tears of the rotator cuff in athletes. j bone and joint surg 1986; 68a (6): 887-891. □ 16 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) pevaryl • broad spectrum antimicrobial action • derm atophytes • yeasts • moulds • gram positive bacteria" • fungicidal effects' • sporocidal effects^ • h ig h m y c o lo g ic a l c u r e r a te o f 9 2 % ' • m in im a l r e la p s e r a te e v e n a f t e r 1 y e a r ' • n o r e s i s t a n c e r e p o r t e d ' often challenged . . . . still unsurpassed pevaryl the no.l topical antifungal econazole nitrate d’ ttnma**'* t j) h u n ■ i n — i i r u . . . . t 3v x«wktiu«muil% n>u h o t on ate < ».*)«: n"rtucu on) un v *'■ r.*! licniijh)k>rt»3 imj.fti 5> scfmrafanfi r kcacanrh ftpon ichl fat |fc ji rndtc proiiikt* (prr) uo 6) os! ’ ( scto.tidtlmwhra|j*cjlw20(i«w> r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the role of arthroscopy in shoulder problems of the athlete ma de beer mbchb m med (orthop)* jf de beer mbchb m med (orthop)t introduction arthroscopy has revolutionized our knowledge o f the anatomy and pathology o f shoulder problems. a r­ throscopy has also vastly improved the accuracy o f diagnoses, and instituted more specific treatment with much better outcome. a surgeon can not adequately deal with shoulder problems without a thorough work­ ing knowledge o f shoulder arthroscopy. impingement the majority o f impingement syndromes in young athletes are secondary to instability and other lesions like labral tears (including s la p lesions). these pro­ blem s can best be diagnosed and treated ar­ throscopically. in primary (structural) impingement in the athlete, resistant to conservative treatment, an ar­ throscopic acromioplasty is the treatment o f choice. the advantages o f arthroscopic acromioplasty (rather than open acromioplasty) are: — the gleno-humoral joint can be inspected to rule out other causes o f impingement (this is mandatory in the "overhead athlete” like throwers, swimmers, etc). — the sub-acromial space can be inspected to confirm impingement. — there is no damage to the deltoid muscle as in open acromioplasty. — there is early return to full function. — there is usually minimal post operative pain. — short hospital stay (can be done on an “out-patient” basis). — cosmetic advantage: no incisions with an unaccep­ table appearance. the results o f arthroscopic acromioplasty have become so good that it will probably be regarded as “ unaccep­ table” to do open acromioplasty in young athletes. posterior impingement posterior impingement is caused by abduction and ex­ ternal rotation o f the shoulder, mostly in throwers. in this position the posteriosuperior glenoid rim acts as a “chisel” stripping the insertion o f the rotator cuff from the greater tuberosity. this diagnosis can only be made with dynamic arthroscopy. s l a p lesions (superior labrum anterior to posterior) these are tears o f the superior glenoid labrum and in­ * jacaranda hospital, suite 3, 213 middelberg st, muckleneuk, 0181, pretoria. tel: (012) 343-0296. f leeuwendal medi-clinic, 3 derwent road, tamboers kloof, 8001, cape town. tel: (021) 23-4040. sertion o f the tendon o f the long head o f the biceps. lesions can only be diagnosed, differentiated and treated arthroscopically. shoulder instabilities arthroscopy has increased our understanding o f shoulder instability and labral tears. the direction, degree and pathology o f instability can be assessed ar­ throscopically. although open surgical repair o f bankart lesions had been regarded as the “gold standard” ar­ throscopic stabilization has becom e a successful pro­ cedure in the hands o f experienced shoulder ar throscopists. the following procedures can be adequate­ ly performed: — anterior bankart repair — posterior bankart repair — capsular plication (multi directional instability) — labral repair (like s l a p lesion repair). rotator cuff tears full-thickness tears: can be accurately detected if there was doubt about the diagnosis. smaller tears can be repaired arthroscopically. partial-thickness tears: occur mostly on the joint side o f the cuff and can only be diagnosed arthroscopically. at the same time they can be debrided using the arthroscope. full-thickness tears o f the rotator crescent, with an intact rotator cable (= “ functional” tears as described by burkhart) can be treated arthroscopically with debridement and arthroscopic acromioplasty. this would usually apply to the older sportsperson in less demanding sports like golf, bowls, etc. acromioclavicular joint pain painful acromioclavicular joint is common in sports people. in those where conservative treatment has fail­ ed, excision o f the lateral end o f the clavicle becomes indicated (“mumford” procedure). this procedure can be adequately performed arthroscopically, in fact the open procedure is less acceptable in the “overhead athlete” as it can lead to dam age to the delto-trapezius fascia and weakening o f the shoulder. the arthroscopic procedure also avoids damage to the acromioclavicular ligament with less likelihood o f joint instability. chondral and osteochondral lesions these lesions o f the joint surfaces can only be diagnos­ ed arthroscopically and can often be treated at the same time. “glad” lesions (gleno-labral articular disruption) is a good example o f this (continued on page 2 3 ) 18 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) rehabilitation of the athlete’s shoulder gisela lauterbach abstract a holistic approach to the rehabilitation o f athlete’s shoulder is presented. factors that should be included 3re posture' spinal and neuromenin geal m obility, physiological and accessory m ovem ents o f all join ts o f the shoulder com plex, stability tests, resisted m ovem ents, and synchrony o f m ovem en t dur­ ing active m ovem ents. d ecrease o f pain and control o f in flam m ation are im portant initial goa/s o f rehabilitar , ° rma ranlg e o f m °vem ent o f all joints o f the shoulder girdle should be achieved before starting with a strengthening programm e and mobilizations should be based on the normal arthrokinematics. dynamic proximal control must be established before adding diss r w 1 y' ? v stren9thening exercises for the rota­ tor cult therefore are o f paramount importance. the hu meroscapular rhythm must be restored during eleva­ tion before strengthening specific muscles. closed ki­ netic chain exercises enhance static control. both con­ centric and eccentric contractions should be included and techniques should be adapted to replicate the bio mechamcs o f the specific sporting activity. progression o f exercises is determined by the control o f movement presence o f pain or related symptoms, and never by i t kanfj u wf r f xtremity strength and endur­ ance work should be included into the programme. the programme should employ correct movement patterns fo rm a n s f retum ° f symptoms and for improved perintrodciction sp^ nj ; on o f the t h ie le ’s shoulder is a commonly seen condition in a sports injuries dinic. symptoms may range from pain during or after activity, weakness, s s l ? f n.sat'ons’ or loss o f performance. varied aps s s ^ t t been describedthe cyriax (1980) approach advocates treating localized lesions bv ;.eep ftrajnsverser actions; travell and simons (1983) identified specific pain distributions o f trigger points o f each muscle which are locally treated. results of “ t6 ° f f n disappointin9 and frustrating for the athlete. too often, treatment is directed to a s p ^ ific component o f the pain only, neglecting the multi-struc­ tural approach to the shoulder complex. • fa,ctors should be considered as possible ori£ £ f r * shoulder f u n c t i o n . in the overhead ath­ lete utilizing repetitive movement o f the arm at hiqh foroesandjccelera tio n , secondary impingement is a department o f physiotherapy university o f cape town anzio road 7925 observatory tommon syndrome. contributing factors are minor in­ a b ilities, loss o f functional stabilization by the scapular muscles, fatigue and/or loss o f depressor action o f the ™ scle (“ amkar 1993). the aim o f rehabili tation is to return the athlete to the previous level o f performance in the shortest, yet safest possible time further; predisposing factors to injury must be identi­ fied and corrected as m ore emphasis is placed on inju­ ry prevention. detailed reviews o f rehabilitation prop in lt t s f^ t f fr° m rec6nt literature (jobe and tq& w s ll‘ ch/ield et al 1993> magarey and jones to s i , a" d ia rn go 1993> the aim o f this paper is s w s t r f , n w i f approach to the rehabilitation o f athletes shoulder. a s a detailed assessment o f the ath­ lete forms the basis o f the rehabilitation programm e components that should be examined are presented assessment maitland (1991) presents a systematic approach to the examination o f the shoulder joint. a detailed history and training programm e o f the athlete is taken the & re ° f tf?e athletj must be analyzed as increased sil?nn h kyp hosis and an anteriorly displaced head po to l h l ih 5 “ ? identified as possible factors leading f f yu unctlon 1992> further, range o f movement o f the cervical and thoracic spine is assessed p h l ^ r s . ls predisposing factors to dysfunction, the accessory movements o f all joints o f the shoulder complex should be tested for range and hnhfn*n hpaik and m usde spasmposterior capsular tightness has been identified as a factor leading to secondary impingement (kamkar 1993) this is as sessed by the amount o f anterior displacement o f the +uis o rah i el ^ 9 passive medial rotation o f the adaucted arm. are perfomied' including apprehension (malone 1994??; r 3nd posterior drawer signs (malone 1994). it is important to determine the ranqe o f movement o f these, the end-feel and the response p . n ..ur!'?g th®se tests. testing positions should be adapted to the athlete's specific biomechanics. for ex­ ample, with the throwing athlete, the anterior drawer sign, usually performed in 9 0 ° flexion in the scapular plane may be repeated in the position o f full flexion £ 5 ? r° ^ t'0nu(f igp with the swimmer it may be s t r o k e ^ ' i l l * p 03!!100 ° f mid-recovery o f the crawl stroke i.e. in the quadrant position. resisted movements are used to determine a soft tis­ sue component, for example lesions of the rotator cuff. however, if these are used as isolated findings, the full functional biomechanics o f the shoulder complex is not appreciated. control o f movement in f u x i a x c sa journal of sports medicine november 1994 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) fig. 1. anterior drawer sign tested in a functional posi­ tion. the relative movem ent between the fixed coracoid and the humeral head is noted. tions is considered more important in the evaluation of shoulder dysfunction than pure reproduction o f pain during a specific resisted test for example, scapula con­ trol and the function of the rotator cuff in various posi­ tions must be tested and compared to the uninvolved shoulder adapting the tests to the athlete’s specific sports activity. isokinetic equipment may be used to as­ sess muscle power. however, these tests are often in non-functional isolated directions in the shoulder joint control and co-ordination o f complex movement are more important than muscle power per se in the shoul­ der join t neuromeningeal structures have been identified as possible components o f shoulder dysfunction (butler 1991) in both overuse and traumatic injuries. the upper limb tension tests are used to assess firstly, the mobili­ ty and integrity o f the neural structures o f the brachial plexus and sympathetic nervous system and, secondly, response of presenting symptoms to these movements. planning o f the rehabilitation programme needs to incorporate every component found to be comparable to the athlete’s symptoms during examination. it should be designed according to the athlete’s specific needs and recipe-type programmes should not be used. rather, signs and symptoms must be re-assessed cons­ tantly and the programme be progressed accordingly. principles of rehabilitation 1. decrease o f pain decrease o f pain and control o f inflammation are im ­ portant initial goals of rehabilitatioa anti-inflammatory modalities, ice and electrotherapy, may be applied. to treat pain, grade 1 and ii passive accessory mobiliza­ tions o f the involved joints are used (maitland 1991). anterior-posterior mobilizations of the cervical spine are effective if neural tension techniques were comparable to the patient’s pain during the examination (fig. 2). 2. increase of range o f movement before starting strengthening programmes it is abso­ fig. 2. anterior-posterior mobilizations o f the cervical spine. lutely necessary to achieve normal glenohumeral and scapulothoracic motion. without normal flexibility ab­ normal movement patterns may be enhanced (pappas et al 1985). mobilization o f the shoulder joint should be based on the normal arthrokinematics the acces­ sory movements o f inferior and posterior glide occur during the first 90° o f flexion, followed by an inferior and anterior glide. specific techniques can be used at the limitation o f the physiological range o f movement as grade iv mobilizations to stretch the capsule and restore normal motion (fig. 3). fig. 3. mobilization o f the posterior capsule. compression through the long axis o f the humerus is added oscillatory on horizontal adduction. athletes often need an increased range of movement for efficient performance and mobilization techniques should be adapted towards these. lateral rotation of 170° in full elevation has been documented in base­ ball pitchers (dillman et al 1993). hypermobility of the anterior shoulder is common in swimmers and is neces20 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) fig. 4. mobilizations o f the thoracic spine. sary during the recovery phase o f the crawl phase. the quadrant position (maitland 1991) best replicates these movements and should be “cleared” before discharging the athlete from rehabilitation. further, mobilization of the cervical and thoracic spine may be necessary if these joints were found to be stiff or painful on exami­ nation (maitland 1987) (fig 4). 3. improvement o f the rotator cuff function the rotator cuff and biceps muscles function as depres­ sors during elevation and have a strong eccentric con­ traction during follow-through o f the throw (diilman et al 1993). if this function is reduced by early fatigue or weakness, impingement o f the cuff occurs against the anterior coracoacromial arch (kamkar 1993). early strengthening exercises, maintaining control o f the scapular position, are therefore o f paramount impor­ tance. isometric contractions using rhythmical stabili­ zation techniques (knott 1968) in neutral position are progressed to various positions o f flexion and abduc­ tion into the direction needed in the particular sport­ ing activity (fig. 5). once painfree control is achieved in various positions, dynamic through-range exercises are added. various methods o f resistance can be em ­ ployed, for example manual resistance by the therapist, self resistance, elastic bands and light weights scapu­ lar control must be emphasized throughout to prevent re-injury. as endurance is an important factor to be con­ sidered, it is advisable to use low weights with high repetition. 4. re-education o f movement the correct muscle firing pattern is an important pre­ requisite for optimum performance and injury preven­ tion. in the shoulder dynamic proximal control must be established before adding distal mobility. the hume roscapular rhythm must therefore be restored during elevation before strengthening specific muscles. as painfree range o f movement is regained, control of the scapula can be achieved in various starting positions, for example using proprioceptive neuromuscular facili­ tation (pn f ) techniques (knott 1968) o f the scapula in side lying. this can be followed by improvement of scapula control in progressive ranges of flexion and ele­ vation in the scapular plane (fig. 6). free active exer­ cises in prone are added, emphasizing rhomboid and lower and middle trapezius muscle strengthening (fig 7). exercises are progressed by adding light weights or using elastic bands. stability exercises include the closed kinetic chain exercises, for example push-upa these facilitate joint compression and stimulate neuromuscular propriocep­ tors to enhance static control (dickoff-hoffman 1994). the serratus anterior muscle plays an important role in proximal stabilization o f the shoulder girdle, and is strengthened during press-ups “with a plus” , i.e. adding full protraction o f the scapula. these are initially per­ fig. 5. rhythmical stabilization techniques for the rota­ tor cuff are used in the eariy phases o f rehabilitation. scapular position is monitored constantly. fig. 6. re-education o f the muscle firing pattern. scapular stabilization is monitored while adding flexion o r abduc­ tion o f the glenohumeral joint. sa journal of sports medicine november 1994 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) fig. 7. free actiue exercises emphasizing interscapular muscle contraction. the arms are horizontally extended while controlling the scapular position. fig. 8. press-up exercises are progressed by using an ex­ ercise ball in the final stages o f rehabilitation. formed against the wall, and progressed to the floor. performing them on a balance board or exercise ball (fig. 8) requires maximum proximal stabilization and should be used in the last phases o f rehabilitation. 5. strength training straight arm exercises in flexion and abduction should never be employed before these movements cannot be controlled sufficiently by the proximal stabilizers, viz. scapular and rotator cuff muscles. pnf patterns, espe­ cially the diagonal flexion/abduction/extemal rotation, can be used in preparation of these, utilizing manual resistance. this has the advantage o f constantly moni­ toring control o f the movement and resistance can be accommodated accordingly. both concentric and eccen­ tric contractions should be included. using these tech­ niques in the seated or standing starting position repli­ cates the activity needed during sports. weight train­ ing on apparatus can be commenced, monitoring sca­ pular control constantly. isokinetic apparatus should be regarded only as an adjunct to functional rehabilitation as movements are isolated to specific directions. progression o f exercises is determined by the con­ trol o f movement, presence o f pain or related symp­ toms, and never by time. further, pelvic control is im­ portant for optimal timing during any biomechanical sequence. pelvic position whilst performing any exer­ cises should therefore be monitored and corrected. trunk strengthening, including abdominal setting ex­ ercises, and lower extremity strength and endurance work should be included into the programme. 6. functional rehabilitation as the aim o f rehabilitation is to return the athlete to previous performance levels, exercises involving the bio­ mechanics o f the specific activity must be incorporat­ ed into the programme. gymnasts will need weight­ 22 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) bearing exercises in various positions. swimmers can work against resistance in the prone position. plyomet rics must be introduced gradually for throwers and rac­ quet sports (fig. 9). a complete programme has been recently described elsewhere (wilk et al 1993). fig. 9. throwing is gradually introduced. emphasis should be placed on muscle tiring pattern and scapular stabilization. rehabilitation of the shoulder may appear very com ­ plex, but if the functional biomechanics are followed and restored, it is very logical and poses a great chal­ lenge. throughout the programme, the normal re­ straints o f healing must be considered, and signs and symptoms must be re-assessed constantly. the pro­ gramme should employ synchrony o f muscle firing and correct movement patterns to prevent return o f symp­ toms and for improved performance. therapists need (from page 18) other lesions there are other problems which may not be particular to athletes but can trouble them: calcific tendinitis in resistant cases arthroscopic removal o f calcific deposits from the rotator cuff is the method o f choice. frozen shoulder (adhesive capsulitis) arthroscopic debridement and capsulotomy can be very effective. conclusion from the above it is evident that the arthroscope has becom e an effective tool when dealing with shoulder to be aware o f all possible causes of dysfunction and if patients do not respond to treatment within expecta­ tions, they must be referred for further investigations as soon as possible. for the earliest possible return to optimal performance levels, communication between all members o f the medical team remains o f paramount importance. references ayub e (1992) posture and the upper quadrant in: donateui r (ed) physical therapy of the shoulder. churchill livingstone. butler ds (1991) mobilization o f the nervous system. churchill livina stone. cyriax j (1980) textbook of orthopaedic medicine volume 2. baiillere tindall. dickoff-hoffman (1994) neuromuscular control exercises for shoulder instability. in andrews jr, wilk ke (ed) the athlete's shoulder. churchill livingstone. dulman cj, fleisig gs, andrews jr (1993) biomechanics o f pitch­ ing with emphasis upon shoulder kinematics. jospt 18: 402-408. jobe fw, pink m (1993) classification and treatment o f shoulder dys­ function in the overhead athlete. jospt 18: 427-432. kamkar a, irrgang jj. whitney sl (1993) nonoperative management o f secondary shoulder impingement sundrome. jospt 17 221-224. knott m, wbss de (1968) proprioceptive neuromuscular facilitation. harper & row. litchfield r et al (1993) rehabilitation for the overhead athlete jospt 18: 433-441. magarey m, jones m (1992) clinical diagnosis and management of minor shoulder instability. austr j physio 38: 269-280. maitland gd (1991) peripheral manipulation. bulterworth heineman. maitland gd (1987) vertebral manipulation. butterworth heineman. malone tr (1994) elements of a standardized shoulder examination. in andrews jr, wilk ke (ed) the athlete's shoulder. churchill livingstone. pappas am et al (1985) rehabilitation of the pitching shoulder. am j sports med 13: 223-235. traueli jg, simons dg (1983) myofascial pain and dysfunction. the trigger point manual volume 1. williams & wilkins. wilk ke, arrigo c (1993) current concept in the rehabilitation of the athletic shoulder. jospt 18: 365-378. wilk ke et al (1993) stretch-shortening drills for the upper extremi­ ties: theory and clinical application. jospt 17: 225-239. □ problems. it has becom e essential for a surgeon deal­ ing with the athlete’s shoulder to master arthroscopic techniques. suggested reading burkhart ss: reconciling the paradox of rotator cuff repair versus debridement arthroscopy 1994; 10: 4-19. bigtiani lu: arthroscopic resection of the distal clavicle. orthopaedic clinics of north america 1993; 24: 133-141. kay sp: arthroscopic distal clavicle excision. clin orthop ret res 1994; 301: 181-184. re lp: management of rotator cuff calcifications. orthopaedic clinics of north america 1993; 24: 125-131. snyder sj: slap lesions of the shoulder. arthroscopy 1990; 6: 274.0 sa journal of sports medicine november 1994 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a survey to determine types and dosages of anabolic androgenic steroids used by competitive bodybuilders in south africa s d titlestad bsc (physio) bsc (med) hon (physio) m i lambert bsc (agric) ba (phys ed) (hon) msc phd m p schwellnus mbbch msc (med) md facsm abstract a questionnaire was sent to all bodybuilders affiliated to two provincial bodybuilding associations (n = 249). out o f the 80 completed returned questionnaires, 30 bodybuilders admitted to using anabolic androgenic steroids (aas). from this sample the a a s which were most frequently reported used were nandrolone decano ate (deca-durabolin® ) (83%), oxymetholone (anapo lon-50® ) (63%), testosterone cypionate (depo-testoste rone® ) (57%), ethylestrenol (orabolin® )(47% ), methe nolone enanthate (primobolan® ) (30% ) and testoster­ one propionate (sustanon-250® ) (40%). the maximum reported dosages used by the bodybuilders exceeded the maximum recommended clinical dosages by up to 18 times. ninety-seven percent o f the users o f a a s reported significant increases in body weight and strength while on a course o f aas. most users obtained the a a s from peers in the gymnasium (63%). seventy three percent used more than one drug simultaneous­ ly (“stacking”) and increased and then decreased their dosages (“pyramiding”). forty percent o f the users were in favour o f a a s production being limited to prevent anyone having an unfair advantage in body-building competitions. this suggests there is pressure for body­ builders to use these drugs this study confirms the anecdotal evidence that a a s are used by bodybuilders in doses which greatly exceed the recommended clini­ cal doses introduction anabolic androgenic steroids (a a s ) were reportedly first used to enhance athletic performance in the mid 1950’s 1 since that time the use o f a a s has increased, being used by athletes in a wide variety o f sports,2, m l lambert m rc/u c t bioenergetics o f exercise research unit department o f physiology university o f cape town medical school observatory, 7925 particularly bodybuilders and powerlifters.3 although it has been reported that powerlifters in south africa self administer anabolic steroids in suprapharmacological doses,4 not much is known about the use o f a a s by bodybuilders in south africa. secrecy surrounds the use o f a a s in bodybuilders not only because o f the possibility o f large fines and possible prison sentences (south african parliament, act 101 o f 1965), but also because o f the controversy surrounding the use o f a a s .1 negative publicity has also made bodybuilders secretive about the types and dosages o f a a s used (underground steroid handbook). therefore, little is known about the types and dosages o f a a s used, although it is apparent that bodybuilders in the usa and europe use a a s in dosages which ex­ ceed dosages for clinical use5’673,910 furthermore, it has been shown in these studies there is no consisten­ cy in either the type or dosage o f a a s used by body­ builders. this is possibly because bodybuilders obtain their information on a a s from either non-scientific sources (underground steroid handbook) or from peers in the gymnasium.3 in south africa, there are no data available about the different types and dosages o f a a s used by body­ builders. therefore, the aim o f this survey was to de­ termine the types and dosages o f a a s used among bodybuilders affiliated to two provincial bodybuilding associations in south africa. methods the population surveyed in this study were all the mem­ bers affiliated to either the western province (n = 80) or natal bodybuilding associations (n = 169). a questionnaire developed in english and afrikaans was validated in a pilot study. th e questionnaire was then sent to all members in the target population. a covering letter explaining the reason for the survey and ensuring anonymity and confidentiality was also in­ cluded. the questionnaire was divided into a general section 24 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) and a section to be completed only by those body­ builders that claimed to have, or were using, aas. four weeks after the questionnaire was sent, a follow up let­ ter was sent to ail members o f the two associations to encourage those who had not returned their question­ naires to do sa a question about the respondent’s body mass and maximal strength (bench press and squat) before and after a course o f a a s was included with the question­ naire. values are expressed as the mean ± standard devi­ ation. a paired t-test was used to detect significant dif­ ferences in the reported body weight preand post-aas use, and differences in the reported maximum bench press and squat preand post-aas use. values were ac­ cepted as being different when p < 0.05. results o f the 169 questionnaires sent to the members o f the natal bodybuilders association, 12 (7% ) were returned uncompleted because o f unknown addresses, and 49 (29% ) were returned completed. o f the 80 question­ naires sent to the members o f the western province bodybuilding association, 6 (8 % ) were returned un­ completed because o f unknown addresses and 31 (39% ) were returned completed. it was decided that the two regions could not be separated or compared be­ cause o f the low percentage response. therefore, all the respondents (n = 80) were grouped and analysed together (35% o f the total). ninety-eight percent o f the respondents stated they had competed in a bodybuilding contest, and 50% had achieved a 1st place in their weight category. fifty per­ cent o f the respondents had com peted at provincial level, 15% had competed at national level, and 6% had competed internationally. seventeen percent o f the to­ tal sample were female (n = 14) and 83% (n = 6 6 ) were male. the average number o f body-building training sessions per week was 5 ± 1 (mean ± sd). o f the 80 completed questionnaires, 30 respondents (28 men and 2 women) admitted to having used a a s (38% o f responders). the average cost per month o f a a s for one user was r500 (range r70 to r2 000) (n = 28). the average age that a a s were first used by the sub­ jects in this study was 27 ± 9 years (range 18 to 53 years). the reasons for the respondents using a a s are shown in table 1. most bodybuilders (83% ) used a a s to increase their physical size (table 1). a number o f respondents indicated more than one reason for usinq aas. the type and dosages o f a a s used by the respon­ dents in this study are shown in table lla and lib with the percent respondents reported using these drugs. in this table the dosages used by bodybuilders are com ­ pared to the maximum recommended doses for clini­ cal use. nandrolone decanoate (deca-durabolin® ) was the most com m only used a a s (83 % ) followed by oxy rnetholone (anapolon-50® ) (6 3 % ) and testosterone cypionate (depo-testosterone® ) (57%). all the users o f nandrolone decanoate (deca-durabolin® ) methenolone enanthate (primobolan® ) and testosterone propionate table 1 reasons for bodybuilders in this sample using a a s (n = 30 ) reason % o f users increased physical size 83 to remain competitive 70 increased strength 43 improved endurance 30 increased resistance to injury 23 improved resistance to fatigue 17 (sustanon-250® ) exceeded the maximum recommend­ ed dose for clinical use. other a a s reportedly used in this study were: methandrostenolone (dianabol® ), ox androlone (anavar® ) and stanozolol (winstrol® ), but these were not reported in table 11 because dosages were not given. these drugs are not available in south africa so it can only be assumed that they were brought into the country. nine o f the respondents reported using the veterinary anabolic steroids nandrolone decanoate (tribolin® ) and boldenone undecylenate (vebenyl® ). these have not been included with table ii because the dosages were not reported. drugs were also used by the respondents to prevent the feminising effects during or after a a s use. tamox­ ifen (nolvadex® and neophedan® ) was used by 34% o f the respondents and human chorionic gonadotropin (apl® and pregnyl® ) was used by 30% o f the respon­ dents. the reported subjective changes and negative side effects experienced by the bodybuilders using a a s in this study are shown in table hi. nearly all users (97% ) reported an increase in body size and muscular strength. both the female respondents reported deepen­ ing o f their voices and increased ditoral size. seventy-three percent o f the respondents stated they “stacked” the drugs and “pyramided” the dosages seventy % o f the respondents used oral and injecta­ ble forms o f a a s concurrently. bodybuilders use a a s in cycles which last between 8-10 weeks, although this may vary (underground steroid handbook). the bodybuilders using a a s in this survey had each taken an average o f 5 ± 4 cycles (mean ± sd) (n = 30). the average reported body weight o f the respondents before a cycle o f a a s was 79 ± 13 kg. subjects report­ ed that their weight after a cycle o f a a s increased to 88 ± 13 kg (p < 0.05, n = 28). there was also a reported increase in strength fol­ lowing a cycle o f aas. average maximum bench press reported before a cycle o f a a s was 104 ± 28 kg which increased to 133 ± 32kg after a cycle (p < 0.001; n = 28). the reported average maximum squat before a cycle o f a a s was 135 ± 42 kg, which increased to 177 ± 54 kg after a cycle (p < 0.005; n = 27). table iv depicts the source where the a a s users in this study obtained their drugs. most users o f a a s ob­ tain their drugs from peers in the gymnasium (63%). more than one source was often used to obtain the a as (table iv). sa journal of sports medicine november 1994 25 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table ha . types, % users, and the range of doses of oral a a s used in the sample of bodybuilders (n — 30). the drugs are classified into anabolic or androgenic according to mims desk reference. doses in this sample of bodybuilders are compared to the maximum recommended clinical dose (mims desk reference) and the per­ cent of responders exceeding this dose are listed. nam e o f aa s % users reported dose range (mg/day) min max max recommended clinical dose (mg/day) % body­ builders exceeding clinical doses oral anabolics (per day) anapolon-50® (50mg/tab) (oxymetholone) 63 50 350 400* (for 80 kg person) 0 orabolin® (2mg/tab) (ethylestrenol) 47 2 20 4 79 primobolan® (5 and 25 mg /tab) (methenolone acetate) 30 10 125 20 79 oral androgenic (per day) proviron® (25mg/tab) (mesterolone) 33 25 100 75 11 androxon® (40mg/tab) (testosterone undecanoate) 20 40 200 160 17 halotestin® (5mg/tab) (fluoxymesterone) 7 10 10 0 table lib types, % users, and the range of doses of injectable a a s used in the sample of bodybuilders (n = 30). the drugs are classified into anabolic or androgenic according to mims desk reference. doses in this sample of bodybuilders are compared to the maximum recommended clinical dose (mims desk reference) and the per­ cent of responders exceeding this dose are listed. nam e o f aa s % users reported dose range (mg/week) min max max recommended clinical dose (mg/week) % body­ builders exceeding clinical doses injectable anabolics deca-durabolin® (25 and 50mg/ml) (nandrolone decanoate) 83 25 300 17 100 primobolan® (loomg/ml) (methenolone enanthate) 30 100 200 50 100 durabolin® (25mg/ml) (nandrolone phenylpropionate) 23 50 300 50 71 injectable androgenic depo-testosterone® (loomg/ml) (testosterone cypionate) 57 100 400 100 65 sustanon-250® (250mg/ml) (testosterone propionate) 40 250 750 83 100 26 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) table iii subjective effects experienced by the users o f a a s in this sample (n = 30). subjective effects % of users increased strength 97 improved size and appearance 97 improved resistance to fatigue 73 increased endurance 70 increased appetite 70 increased sex drive 60 increased water retention 60 disturbance o f normal sleep pattern 40 less prone to injury 37 increased body hair 37 decreased sex drive 33 testicular atrophy 33 greater number o f headaches 27 increased acne 23 deepening o f voice 20 gynaecomastia 17 pins and needles 17 nosebleeds 7 stopped growing 3 increased clitoral size (n = 2) 100 in 1992, a a s were re-classified to schedule 5 drugs. penalties for an infringement o f drugs in this class may be up to a r40 000 fine or 10 years in prison (south african parliament, act 101 o f 1965). o f the respon­ dents using a a s in this study, 37 % stated this change in the law had affected their decision to take a a s and 60% stated a a s were now m ore difficult to get. forty percent o f the users felt that a a s production should be stopped completely. table iv the sources used by bodybuilders in this study (n = 3 0 ) to obtain a a s . source % of users gymnasium friends 63 doctor (other than family doctor) 27 pharmacist 23 family doctor 17 gymnasium owner/instructor 3 discussion the most important finding from this study was that except for oxym etholone (anapolon-50® ) and fluox ymesterone (halotestin® ), bodybuilders in south africa use doses o f a a s which exceed the recommended dose for clinical use. this is comparable to bodybuilders in the usa who used up to 4 times the recommended clin­ ical doses.10 furthermore, this study confirmed that most body­ builders reported to “pyramid” the dosage and “stack” types o f steroids which agrees with previously report­ ed information (underground steroid handbook,5’ 10). the use o f tamoxifen (nolavadex® and neophe dan® ) by 34% respondents and human chorionic gonadotropin (apl® and pregnyl® ) by 30% o f the re­ spondents indicates that bodybuilders try to avoid side effects such as gynaecomastia and testicular atrophy during and after a a s .11 mesterolone (proviron® ) was also used by 33% o f the respondents to reduce the feminising effects o f a a s (underground steroid hand­ book). in reported clinical trials there is no consensus on the effect o f a a s on body mass and strength changes.12 despite this controversy in the scientific press, bodybuilders believe that a a s improve strength and body mass (underground steroid handbook). in this study both the reported body mass and strength increased significantly after a cycle o f aas. although these are subjective data, it does indicate that body­ builders do believe a a s cause an increase in body mass and strength. according to the literature5 som e most commonly used a a s are veterinary preparations. in this survey veterinary preparations (tribolin® and vebenyl® ) were used by 30% o f the bodybuilders. these drugs are mar­ keted for use in horses. the reason for bodybuilders using them is that the preparation tribolin® (veterinary preparation) for ex­ ample, contains nandrolone decanoate, which is also in deca-durabolin® (human preparation). furthermore, the veterinary drugs are cheaper. however, veterinary preparations are considered to be highly toxic and dan­ gerous to humans (underground steroid handbook,5) because o f the impurities which may occur in these drugs resulting from the less stringent quality control in their manufacture. all the results o f this study were based on the respon­ dent’s (35 % ) answers to the questionnaire. the anony­ mous nature o f the questionnaire made it impossible to characterize the non-responders in the study. it can therefore not be assumed that the bodybuilders in this study are necessarily representative o f bodybuilders in south africa. in summary this study documents the reported use o f anabolic androgenic steroids in a selected sample o f bodybuilders in south africa, and describes the types and dosages o f drugs used. this study agrees with re­ ports from the usa that doses o f a a s used by body­ builders exceed recommended maximum doses for clinical use. clearly users o f a a s believe the drugs are offering them som e advantage at these high doses. although the adverse side-effects o f a a s in these high doses have been well characterized,14a61112 this does not seem to deter the users. this can possibly be ex­ plained by the fact that although the bodybuilders are well informed about the side-effects o f a as, they are pressurized into using the drugs to remain competitive. this is confirmed by the respondents in this study (40% ) who were in favour o f a a s production being limited to prevent a possible unfair advantage by a a s users in bodybuilding competitions. although the new legislation on a a s has had some effect on their avail­ sa journal of sports medicine november 1994 27 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ability, tighter regulation in the production and distri­ bution o f use o f a a s is needed. the south african bodybuilding association also needs to take a firmer stance against the use of aas by bodybuilders affiliated to their organization. references 1. haupt ha and rouere gd. anabolic steroids: a review of the liter­ ature. am j sports med 1984; 12: 469-484. 2. elashoffjd, jacknow ad, shain sg and braunsteln gd. effects of anabolic-androgenic steroids on muscular strength. ann ini med 1991; 115: 387-393. 3. goldman b, bush p and klatz r. death in the locker mom. steroids and sport icarus press inc, south bend, indiana, usa, 1984. 4. cohen jc, moakes t and benade ajs. hypercholesterolemia in male power lifters using anabolic-androgenic steroids. phys sportsmed 1988; 16: 49-55. 5. wilson jd. androgen abuse by athletes. endocrine reo 1988; 9: 181-199. 6. wilson jd and griffin je. the use and misuse of androgens. metabolism 1980; 29: 1278-1294. 7. alen m and hakkinen k. physical health and fitness of an elite bodybuilder during 1 year of self-administration of testosterone and anabolic steroids. a case study. int j sports med 1985; 6: 24-29. 8. forbes gb. the effect of anabolic steroids on lean body mass: the dose response curve. metabolism 1985; 34; 571-573. 9. alen m, hakkinen k and komi pv. changes in neuromuscular per­ formance and muscular fibre characteristics of elite power athletes s e lf administering androgenic and anabolic steroids. acta physiol scand 1984; 122: 534-544. 10. burkett ln and falduto mt. steroid use by athletes in a metropoli­ tan area. phys sportsmed 1984, 12: 69 74. 11. fried! k and yesalis cd. self treatment of gynaecomastia in bodybuilders who use anabolic steroids. phys sportsmed 1989; 17: 67-79. 12. hickson rc, ball kl and falduto mt. adverse effects o f anabolic steroids. med toxicol adverse drug exp. 1989; 4: 254-271. d cict sports medicine information service sports medicine is a relatively new discipline of medicine. there is hence a rapid expansion of knowledge in the areas o f exercise physiology, exercise biochemistry, medical aspects related to physical activi­ ty and sports related injuries obtaining the informa­ tion may be difficult because o f limited access to library services, excessive cost of international journal subscrip­ tions and limited tim e for literature searches by busy pharmacists. the uct sports medicine information service can solve these difficulties for you. yog will benefit from the uct sports medicine information service if you are a phar­ macist interested in sports medicine. the uct sports medicine information serv­ ice provides you with: — annual subscription to a specialised sports medicine information service at a cost lower than subscription to one international journal — a monthly list of important recent publications which have been identified by experts — the option o f requesting a copy o f any o f the listed publications at a minimal cost per page — an income tax certificate is available. a pplic atio n form s a n d further inform a­ tio n c an be obtained from: u c t smis p o box 38567 pinelands 7430 or please phone dr m p schwellnus at (021) 406-6504. wlvotlarenls t a b l e t s diclophenac sodium 7 5 mg _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ d f c c s ] l/9< diclophenac sodium 75 mg § § m m jif voltaren 75 i i q tafttoa 28 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a profile of biokinetic services in south africa from 1988 to 1991 mf coetsee m a (phys ed) (stell) phd (clpe) abstract a survey was undertaken to establish the nature and extent o f biokinetics services in the republic o f south africa for the years 1988-1991. questionnaires were sent to all biokinetic centres and practices the results show that biokineticists willing to enter full time practice (as oposed to those working part-time) increased from 45% in 1988 to 73% in 1991. a growing trend in patient numbers was also experienced i.e. from 5 736 (286/centre) in 1988 to 11 241 (750/centre) in 1991. o f the patients seen by biokineticists, 41% were referred by other medical disciplines the highest proportion of referrals came from orthopaedic surgeons (34,9% in 1991) followed by general practitioners (18,2% in 1991) and physiotherapists (13,0% in 1991). these results il­ lustrate the growth o f biokinetics as a member o f the multi-disciplinary health team. introduction on 9 september 1983, the profession biokinetics was formally announced in the government gazette.1 it can therefore be regarded as a relatively young m em ­ ber o f the health profession. biokinetics is defined as “the profession that deals with scientifically founded and controlled physical activities with regard to the fol­ low ing: 1. p ro m o tin g physical perform an ce; 2. prevention o f ailments; 3. final phase rehabilitation; and 4. physical selection.”2 biokinetics thus aims to promote quality o f life by means o f physical assessment and prescription o f rehabilitative and preventative ex­ ercise. the benefits o f physical exercise has been well researched and documented notably, on 19 february 1992 the american heart association issued an offi­ cial position statement recognising inactivity as a risk factor for coronary artery disease.3 department o f human movement science university o f zululand private bag x1001 kwadlangezwa 3886 the aim o f this research project launched, in 1988, is to monitor the growth o f biokinetics and the sup­ port it has gained from other members o f the medical profession. the results o f the last four years are now available and this article attempts to summarize these findings methods and procedures in january o f each year, from 1989 to 1992, question­ naires were sent to all biokinetic centres and practices respondents were requested to fill out the question­ naires using patient/subject data pertaining to the previ­ ous year. over the four years o f the study the number o f responses were as follows 1988 = 20; 1989 = 8; 1990 16; and 1991 = 15. because some centres and practices employed more than one person the actual number o f biokineticists and assistant biokineticists that were involved were: 1988 = 33; 1989 = 19; 1990 = 37; and 1991 = 37. the reason for the drop in re­ sponses in 1989 may be attributed to a change in the questionnaire i.e. in addition to the existing question­ naire respondents were asked to categorise orthopaedic cases according to the site o f injury and information on referral o f patients it seems as if the respondents had difficulty in completing the more comprehensive questionnaire the first year it was introduced. since 1989 the questionnaire remained unchanged and the number o f responses increased possibly due to better record keeping during the previous year. the questionnaire involved four categories i.e. 1. to determine the ratio o f full time and part time practices; 2. to determine the patient numbers seen by biokineti­ cists; 3. to determine the extent and nature o f referrals to biokineticists from members o f the medical profes­ sion; and 4. to determine the nature o f services ren­ dered by biokineticists results and discussion ratio of full-time to part-time practices the ratio o f part time vs full-time practices changed appreciably over the four years since 1988. the 1988 survey showed that 45% o f all practices were full-time sa journal of sports medicine november 1994 29 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) practices and 55% part time practices. after a drop to 38% in 1989 (possibly due to the low response rate as discussed in the previous section) the full time prac­ tices increased to 56% in 1990 and 73% in 1991. this points to a growing confidence in the viability o f bi­ okinetics as a full time profession despite the high costs o f setting up a practice. patient numbers seen by biokineticists the total number of patients seen at the respective bi­ okinetic centres that responded over the 4 years was as follows: 1988 5 736; 1989 = 1 122; 1990 = 9 582; and 1991 = 11 241. the average number o f pa­ tients seen per centre was calculated as follows: 1988 = 286; 1989 = 140; 1990 = 599; and 1991 = 750. apart from 1989 (possibly the results are affected by the low response) these results point to a growing de­ mand for biokinetic services. referrals from other m em bers o f the medical profession being part o f a multi-disciplinary team, biokineticists place a high emphasis on cooperation with other med­ ical and para-medical professions. the survey for 1988 showed that 31,1% o f the total patients seen by bi­ okineticists were referred by other medical professions. the figures for the following years were: 1989 = 39,8%; 1990 = 49,6%; and 1991 = 43,1%. this indicates posi­ tive cooperation between biokineticists and other med­ ical professionals. in response to the questionnaire, views regarding the cooperation between biokinetics and other disciplines varied from excellent to poor, sug­ gesting that although many members o f the medical profession cooperate with biokineticists, a lack of awareness still exists it is hoped that this article might help to promote greater cooperation in order to benefit the patient knowledge regarding the type o f patient referrals bioprofile o f patient cases seen by biokineticists during 1988-1991.____________________ 1988 1989 1990 1991 (% ) (% ) (% )__________ (% ) 20,7 30,6 37,5 3,2 4,4 6,5 7,1 12,8 13,4 0,6 1,5 1.8 7,1 7,8 9,3 1,7 2,6 4,2 0,6 0,5 1.2 0,4 1.0 1.1 o rth o paed ic foot/ankle knee hip back shoulder hand/arm neck cardiac co nd itio ns coronary risk documented coronary condition pre-participation evaluation h ypo k in e tic conditions hypertension cholesterol obesity posture other asthma diabetes . arthritis osteoporosis emphysema psychological neurological gynaecological sp o r t evaluations 9,3 14,3 12,4 5,8 10,8 7,2 2,2 3,5 5,2 3,6 23,8 21,5 18,6 18,9 19,9 25,3 23,1 17,1 0,6 13,5 4,8 5,8 0,4 1.9 6,2 3,7 10.9 9,1 7,8 4,4 8.0 0,8 4,3 3,2 0.8 4,7 5,0 6,6 0.3 1,1 0,9 0,6 0 1,0 0,9 0,7 0,5 2,6 3,2 2,2 0 0 0 0,2 0 0 0 0,1 0 0 0 1,2 0 0 0 0,6 0 0 0 1,0 10,6 13,5 103 14,1 30 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) kineticists receive, is very important for upgrading the type o f biokinetic training that will be offered in the future. table 1 gives a profile o f referrals to biokinetic practices from 1989 to 1991. the highest number o f referrals came from orthopaedic surgeons followed by general practitioners and physiotherapists. table i profile o f referrals for biokinetics from 1989 to 1991 1989 <%) 1990 <%) 1991 (% ) orthopaedic surgeons 13,4 26,3 34,9 general practitioners 41,0 25,3 18,2 physiotherapists 23,9 15,8 13,0 coaches 6,7 14,1 8,6 cardiologists 3,5 6,6 7,1 dieticians 1,2 2,0 6,3 specialist physicians 1,2 5,6 4,6 gynaecologists 1,8 0,3 3,2 psychologists/ psychiatrists 0 0,1 2,1 podiatrists 0 0 0,6 occupational therapists 0 0 0,6 nursing sisters 7,3 0,1 0,5 chiropracters 0 0,8 0,2 neuro-surgeons 0 3,0 0,1 interesting trends were revealed regarding the type of work most prevalent in a biokinetics practice (table ii). biokineticists are predominantly engaged in orthopaed­ ic rehabilitation, particularly rehabilitation of the knee. another major area is the physical evaluation o f in­ dividuals, prior to their engagem ent in any activity, in order to assess the safety o f their participation. the third area biokineticists are actively involved in, is the prescription o f exercise as a m ode o f rehabilitation for individuals exhibiting certain hypokinetic problems such as hypertension, high cholestrol, obesity and bad posture. the last, but progressively more demanding area o f involvement, is the assessment o f sportsmen in an attempt to identify possible shortcomings, op­ timize training, monitor progress and in so doing im­ prove performance. conclusion the research data collected thus far, clearly demonstrat­ ed that biokinetics has gained acceptance as a m em ­ ber o f the multi-disciplinary health team in both re­ habilitative and preventative medicine. it has been es­ tablished that a variety o f other medical disciplines cooperate with biokineticists. biokinetics, being a fair­ ly young discipline, is showing an escalating growth rate in the number o f patients making use o f its services. references 1. strydom g l. bioldnetika: a s professioneie dissipline — htstoriese o orsig en ontwikkeling (uitgawe 2 ) pbtchefstm om p u uir c h o , 1989. 2. biokinetic activities as approved b y the professional board for m e d ­ ical scientists in 1993 and submitted for publication in the g overn ­ m ent gazzette. 3. fletcher g f et al 1992. a h a m edical/scientific statements, state­ m ent on exercise. circulation vol 86, h o 1. □ erratum table 1 basic skeletal muscle fibre type classifications skeletal muscle fibre types nomenclature type 1 11a 1ib slow fast oxidativefast oxidative glycolytic glycolytic so fog fg characteristics: colour red red white twitch slow fast fast atpase activity low high high lost at ph 9.4-10.4 4.4-4.6 4.4 glycogen content low high high fatigue resistance high high low oxidative capacity high high low an error inadvertently occured in table 1 in the review article by k.h. myburgh, “muscle proteins and the con­ tractile properties o f muscle fibres” . (sa journal o f sports medicine vol 1 no 1: 13, 1994). th e corrected table appears below. sa journal of sports medicine november 1994 31 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) readership survey if you w ish to con tin ue receivin g this journal, free o f charge, p lease fill in the form b elow and return it to: glenbarr publishers cc private bag x i4 parklands 2121 name:.................................................................................................................... address:................................................................................................................. code:............ speciality: 32 sa journal of sports medicine november 1994 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial 1 sajsm vol. 33 no. 1 2021 creative commons attribution 4.0 (cc by 4.0) international license south african journal of sports medicine: what happened in 2020 and plans for 2021 it has become cliché to comment on the hardships most people faced as a consequence of the pandemic in 2020. without trivialising these hardships, the south african journal of sports medicine had a bumper year. the published outputs of the journal doubled in 2020 compared to the number published in each of the previous two years. there were 7105 downloads of papers published in 2020. the most popular paper based on number of downloads was “implications of covid-19 for resumption of sport in south africa: a south african sports medicine association (sasma) position statement part 1” with 653 downloads; the abstract for this paper was viewed 1537 times.[1] the paper “physical and physiological profile of u18, u19, u21 and senior elite netball players”[2] had 514 downloads and the paper “brace yourselves: esports is coming” was the third most popular paper with 424 downloads.[3] the broad interest in physical activity and sport and covid-19 was not neglected. two commentaries on covid-19, two position statements compiled by the south african sports medicine association and one short report on the wearing of face masks during exercise were published. these outputs on covid-19 have contributed to the public message and guidelines for exercising and playing sport during the pandemic. in addition to the traditional metrics quantifying the uptake of papers, altmetric data can also be used to assess the journal’s impact. altmetrics assess data from the internet such as mentions made on social networks, wikipedia and public policy documents. these data provide another dimension for assessing how a paper has been received. according to these criteria, the paper “testosterone boosters: a report of a supplement’s misleading labelling claims” [4] has the highest score followed by the “the currie cup premiership competition injury surveillance report 2019”. [5] there were 537 tweets on the published content of the south african journal of sports medicine in 2020. these tweets were posted by 234 unique tweeters from 26 countries. besides south africa, most of the tweeters were from the united kingdom, ireland, australia and the united states. there were 12 news stories about the content of the journal in 2020 communicated by seven unique news outlets in five countries (australia, united states, zimbabwe, turkey and new zealand). another statistic is that authors from the university of the witswatersrand had the most outputs, followed by the university of cape town, and university of pretoria. much of the success of the journal can be attributed to the high quality reviews of the submitted papers. the pool of dedicated reviewers invited to review papers submitted to the south african journal of sports medicine invested much time in trying to improve the quality of the paper they were asked to review. in some cases the reviewers interacted with the revised paper up to four times before it got accepted for publication. although this is frustrating for the authors, there is no doubt that the final published version is vastly improved compared to their original submitted paper. reviewing is a thankless task for which there is no monetary reward or public recognition. most journals find it difficult to find reviewers. however, this has not been a major obstacle for the south african journal of sports medicine. the south african journal of sports medicine has also been fortunate to be supported by the academy of science of south africa (assaf) who have provided the infrastructure for the journal’s website. they are quick to respond to any queries related to the open journal systems (ojs), the software application used for the online presence of the journal. assaf have also hosted workshops for editors and journal managers to ensure they remain up-to-date with the new developments in the academic publishing world. the south african journal of sports medicine remains accredited by the department of higher education and training. therefore authors from south african academic institutions can claim their subsidy after their paper is published. however, the subsidies are dealt with differently at each institution. while it is important to look back and acknowledge accomplishments, this should be balanced with looking forward to plan goals. with that said the journal has an exciting year ahead. the first goal is to increase the number of outputs and downloads in 2021. several papers are already in an advanced stage of review, so the year should get off to a good start. the second goal is to get the journal listed by the web of science database. this is a challenging task in which the current and past quality of the papers published by the south african journal of sports medicine are reviewed by a panel. achieving both goals will raise the journal to the next level of accomplishment. the south african journal of sports medicine will also be working with the organisers of the international festival of sports and exercise medicine conference to publish their peer-reviewed conference abstracts. this conference represents the south african society of biomechanics, south african sports medicine association, life through movement international conference and the african physical activity network. the conference will be held at the csir international convention centre in pretoria from the 22-24th october 2021. let the games begin! mike lambert editor-in-chief s afr j sports med 2021;33:1-2. doi: 10.17159/2078-516x/2021/v33i1a9378 references 1. ramagole d, janse van rensburg dc, pillay l, et al. https://www.assaf.org.za/ https://www.assaf.org.za/ https://www.ifsemc2021.co.za/ https://www.ifsemc2021.co.za/ http://dx.doi.org/10.17159/2078-516x/2021/v33i1a9378 https://orcid.org/0000-0001-8979-1504 editorial sajsm vol. 33 no. 1 2021 2 implications of covid-19 for resumption of sport in south africa: a south african sports medicine association (sasma) position statement. s afr j sports med (online) 2020; 32(1): 1–6. [doi.org/10.17159/2078-516x/2020/v32i1a8454] 2. sinclair c, coetzee ff, schall, r. physical and physiological profile of u18, u19, u21 and senior elite netball players. s afr j sports med (online) 2020; 32(1): 1–7. [doi.org/10.17159/2078516x/2020/v32i1a6545] 3. kemp c, pienaar p, rae d. brace yourselves: esports is coming. s afr j sports med (online) 2020; 32(1): 1–2. [doi.org/10.17159/2078-516x/2020/v32i1a7596] 4. de lange rw. testosterone boosters: a report of a supplement’s misleading labelling claims. s afr j sports med (online) 2020; 32(1): 1–3. [doi.org/10.17159/2078-516x/2020/v32i1a7426] 5. starling l, readhead c, viljoen w, et al. the currie cup premiership competition injury surveillance report 2014 – 2019. s afr j sports med (online) 2020; 32(1): 1-43. [doi:10.17159/2078-516x/2020/v32i1a8560] http://doi.org/10.17159/2078-516x/2020/v32i1a8454 http://doi.org/10.17159/2078-516x/2020/v32i1a7596 south african journal of sports medicine sportgeneeskunde j o u r n a l o f t h e s.a. sp o rt s m e d i c i n e a s s o c ia t io n t y d s k r if van d ie s.a. sp o r t g e n ee s k u n d e -v e r e n ig in g volume 6 number 3 june/july 1991 national advisory board editor in chief: clive noble associate editors; p rof td noakes dawie van velden advisory board: traum atology: etienne hugo physiotherapy: joyce morton n utrition: mieke faber biokinetics: martin schwellnuss epidem iology: derek yach radiology: john straughan physical education: hannes botha internal m edicine: francois r etief international advisory board lyle j micheli a ssociate clinical professor o f orthopaedic surgery chester r kyle research d irector, sports equipm ent research associates p ro f hc wildor hollmann president des deutschen sportarztebundes howard j green professor, d epartm ent o f k inesiology george a brooks professor, d epartm ent o f physical education neil f gordon d irector, exercise physiology edmund r burke a ssociate professor, biology d epartm ent, u niversity of colorado graham n smith p hysiologist c o n t e n t s editorial comment h ealth care in the new south a frica .............. 3 p sy ch o lo g y p sychological dim ensions o f sports injuries .. 4 c ric k e t c ricket injuries a rev iew .............................. .. 9 n u tr itio n t he effect o f dietary cholesterol on plasm a cholesterol le v e ls .................................................... 14 s a s m a update sa sm a new s ........................................................... 18 p h y s io th e ra p y t reatm en t o f soft tissue injuries: the facts about f r ic tio n s ................. ... . . . . . 19 t h e c om rades m arathon as seen through the eyes o f a physiotherapist ........... ....... ....... 22 journal of the south african sports medicine association 269 west avenue hennopsmere verwoerdburg, 0157 sasgv sasma photographs courtesy o f the image bank t h e journal o f the sa sports m edicine a ssociation is p ublished b y m e d p h a rm p ublications, 3rd f lo o r n oodhulpliga c e n tre , 204b h f v erw o erd d riv e, r an d b u rg 2 1 9 4 . po box 1004, c ram er v ie w 2 0 6 0 . t el: (011) 7 8 7 -4 9 8 1 /9 . t h e view s ex p ressed in this pub licatio n are th o se o f th e authors and not necessarily those o f the p ublishers. p rin te d b y t h e n a ta l w u n c « p rin tin g an d p u bfu jim g c o m p a n y (p r y ) ltd r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the com p lete one-a-day multivitamin and mineral supplem ent em vit keep s y o n c \o in g i m a d a u s p h a rm a c e u tic a ls (p ty ) l td . p.o. b o x 7 6 2 4 6 , w e n d y w o o d 2 1 4 4 keep ahead wit-h reparil-gel • ■ g2 3 6 7 ' ‘ ------------1 0 0 g c o n ta in s : a e s c in 1,0g; a e s c in s o d iu m p o ly s u lp h a te (h e p a rin o id ) 1,0g; d ie th y la m in e s a lic y la te 5 ,0 g get up cw4 go with magnesit* f s/24/192 magnesium f aspartate hcl 1 229,s m g ^ ^ for magnesium deficie n cy's^r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) e d i t o r i a l h e a l t h c a r e in t h e n e w so u t h a f r ic a in the n ew south a frican health care fo r all will becom e the o rd e r o f the day. w ith the unlikelihood o f m uch additional funding being available to achieve this, one must look at the effects this w ill have on sports m edicine. t h e m ajor cost in sports m edicine is the treatm ent o f sports injuries. t hus, if trea t­ m ent can b e avoided by prevention, a great saving can be achieved. im proved facilities and coaching techniques to all race groups w ould go a long way in this regard. this w ould not form part o f the health budget. at this p o int in tim e, sports m edicine fa­ cilities are part o f south a fric a 's first w orld, i.e. fo r w hites and blacks on m edical aid as well as the richer black soccer clubs that can afford such facilities. m ost o th er injured blacks are treated by w itch-doctors with the tell-tale scratches occurring on the injured part. seeing that m any sports injuries get b etter w ith tim e alone, in the past this was acceptable "therapy". h ow ever, w ith aids becom ing a m ajor problem this m ethod o f treatm ent w ill cause aids to spread unless adequate sterilisation procedures are o b ­ served. a lso, aids becom es im portant in sports w here bleeding may o ccur such as boxing and o th er collision sports. a dequate precautions such as the use o f ru b b er gloves by the seconds and referee, o r stopping o f a fight once bleeding occurs, may becom e m andatory. t h e answ er to m ost o f the sports m edi­ cine requirem ents is education grass roots level. all coaches and trainers should do a co u rse in first aid w ith a sports m edicine bias. t hey should also have a know ledge o f rehabilitation, know ing w hen an injured play er can return to sport with the least chance o f reinjury. f irst aid should be available at all sporting venues. this can be done w ithout o v er straining the resources o f the first aid groups by, fo r exam ple, at school level having children w ho are unable to play sport b ecause o f ill health o r other reasons jo in the team as first aiders. s im i­ larly at clubs, supporters can b e turned into first aiders. a m inim um standard o f equip­ m ent can be set w ithout overb u rd en in g the club o r schools finances. these sam e school first aiders can, with tim e, im prove th eir know ledge and in rural areas becom e p rim ary health p ersonnel run­ ning clinics w hich can then re fer problem s to peripheral hospitals. t hey may also becom e nurses o r even doctors so vital in the new south a frica. p aram edical education can also be ex­ tended to the third w o rld . s ports m edicine should also form a la rg e r p art o f medical training at o u r universities and colleges, both fo r do cto rs and nurses. s ports m edicine diplom as and d e­ grees should be available at all universities with m edical schools. d epartm ents o f sports m edicine at all m edical schools should b e m andatory. this w ould ensure b etter healthcare fo r all o u r sportsm en and w om en. a u t o p i a ...... maybe. d r c live n o b le m b b ch, fc s (sa) e d ito r-in -c h ief ________________________ 3 spo rtsg eneesku nd e vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychology psychological dimensions of sports injuries jr potgieter t he m any excellent books and jo u rn als p ublished in recent years b ear testim ony to p ro g ­ ress in the field o f sports m edi­ cine d u rin g the p ast decade. closer inspection o f these texts, h ow ever, reveals a d earth o f literatu re on the psychological dim ensions o f the reh ab ilita­ tion o f injured sportsm en. a lthough this is n ot a healthy state o f affairs, it is, nev erth e­ less, no t surprising. t h e causes o f sports injuries a re p rim arily o f a physical nature. h o w ev er, psychological factors should not b e discounted. s portsm en are p ractical p eo p le and w o rk hard and in a disciplined way on th eir ph y si­ cal conditioning and skills. a lthough they invariably re ­ cognise th e im p o rtan ce o f p sy ­ chological dim ensions in sport, psychological training occupies a relatively m in o r p lace in m ost training regim ens. in addition, in the w orld o f sports th ere is som e resistan ce to utilising the services o f so-called sport psyjr potgieter departm ent o f human m ovement studies university o f stellenbosch chologists to enhance physical p erform ance. t h e p ro cess o f sport socialisation m akes it difficu lt fo r the sportsm an to enlist the services o f a p sy ­ chologist, because such a step is o u t o f line w ith the accepted values o f sports participation such as toughness, d eterm in a­ tion, p ersistence, assertiveness and aggression. t he "old school" approach creates a m i­ lieu that could p erceiv e the consultation o f a psychologist as a sign o f w eakness. r e­ search has verified this as­ sum ption (c arm en e ta l, 1968; linder et al, 1989; pierce, 1969; scanlan et al, 1989). need for a psychological approach i f it is tru e that the average healthy sportsm an is reluctant to consult a psychologist it is n ot surprising that he is also apprehensive to seek p sycho­ logical assistance when injured. a long with the im proved treat­ m ent o f injured sportsm en it has, how ever, becom e im p o r­ tant to focus on the p sy ch o lo g i­ cal dim ensions o f reh ab ilita­ tion. b ecause the sportsm an can now adays retu rn to an a c ­ tive p ro g ram m e afte r a rela­ tively short p eriod o f tim e, psychological com plications may arise. in m any cases this shortened rehabilitation tim e m ay no t b e long enough fo r the injured sportsm an to adjust p sychologically. h e m ay be p hysically ready fo r re-entry into the sports aren a b u t his m ental ad ju stm en t has no t been com pleted. t h e traum atic rem in d ers o f his injury are still fresh in his m em ory w hile, at the same time, external demands a re placed on him to perfo rm physically. a nxiety and self­ d o u b t as w ell as real fears o f a recu rren ce o f the sam e injury o r an injury to an o th er p a rt o f the body may plag u e him (ro tella & h ey m an, 1986). t h e fact that serious com petitors a re highly com m itted and m ake significant investm ents in th eir sport, m akes these fears even m o re significant. r ehabilitation o f the injured sportsm an is th erefo re both a p hysical and psychological p rocess. it follow s that the sportsm an as a w hole should b e treated and no t only the injury. b ecause the em otions are in v o lv ed , sports m edicine pro fessio n als need to attend to the p sychology o f the injured sportsm an (e ld rid g e, 1983). reactions to injury a t the ou tset it m ust b e p ointed o u t that m any sportsm en do not 4 sports medicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychology need any special psychological treatm ent. s portsm en react to injury in d ifferen t w ays. w ith a sound physical rehabilitation p ro g ram m e and the necessary su p p o rt and en couragem ent m ost sportsm en are ab le to o v erco m e th eir in ju ries suc­ cessfully and w ithout any significant negative effects. som e m ay even view th eir in ju ries as a fu rth er o p p o rtu ­ nity to display co u rag e, com ­ m itm ent, self-discipline and p ersev eran ce. in contrast, fo r o th ers, injury could p ro v id e a b reak from a taxing training regim en and an escape from the dem ands placed on them (ro te lla & h e y m a n , 1986). it p ro ­ vides an excuse fo r below p a r p erfo rm an ces. h o w ev er, fo r o th ers an in ju ry could present a tru e crisis w h ere p sy ch o ­ logical intervention is indicated (l ittle, 1979). stress as a predisposing factor r esearch findings strongly suggest that th ere is a re la ­ tionship betw een stressful life events o r even o rd in ary daily hassles and a sp o rtsm an ’s p redisposition to injury (bram w ell et al, 1975; c oddington & t ro x el, 1980; c ryan & a lles, 1983; p asser & seese, 1983). a lthough m ost o f the research has been done on contact sports, such as foo tb all, th ere a re indications that this re ­ lationship also holds fo r non contact sports (k err & m in den, 1988). it is hypothesised that the p resen ce o f these stressful events decreases the sp o rtsm an 's coping ability (m iller et al, 1990). d aily hassles dem and attention and the resulting division o f atten ­ tion betw een stressful events and the task at hand can be a cause o f injury. t he m ere physical fatigue resulting from a stressful life can be a logical answ er fo r an increase in in ju ­ ries am ong sportsm en w ho are experiencing daily stress. t he o ccu rren ce o f injuries at critical tim es ju s t p rio r to an im portant com petition cannot be explained with certainty. it m ay m erely b e the result o f in ­ tensified training, b ut a p o s­ sible cause could b e attributed to the heightened stress as the day o f an im portant co m p eti­ tion approaches. b ecause avoiding injury p rio r to such com petitions is o f im m ense im portance, it is advisable in som e cases to assist sports­ men psychologically to co u n ter the effects o f daily stress. a ndersen and w illiam s (1988) suggest that it m ay be neces­ sary to assess a sp o rtsm an 's coping behaviours such as sleep p attern s, nutritional habits, tim e m anagem ent, general self-esteem and if the athlete is a student, study skills. t he use o f stress m anagem ent p ro g ram m es, relaxation tech ­ niques, cognitive restructuring, and social support can enhance the coping skills o f the sports­ m an. understanding the world of the injured sportsman em pathy is a key concept in the rehabilitation o f the injured sportsm an. t h e therapist and coach can enhance this em p a­ thy by understanding the w orld o f the particip an t and w hat it m eans to him . p articipation in re g u la r exercise and sport has the potential to enhance p sy ­ chological w ell-being (sachs, 1984). t he p articip an t not only derives en joym ent and satis­ faction from sp o rt b u t also d e­ rives feelings o f com petence and con tro l. f u rth e rm o re , p ar­ ticipation in sp o rt and physical ex ercise m ay serve as an im ­ p o rtan t w ay o f red u cin g stress and dealing w ith depression. w hen considering the psycho­ logical and social benefits, it is no t surprising that a sudden term ination o f participation could b e a traum atic experi­ ence fo r the sportsm an. this p ro v id es a p artial explanation o f w hy injured sportsm en, against m edical advice, con­ tinue to p articip ate in activities such as run n in g . it is suggested that these individuals find it m o re acceptable to handle the physical d isco m fo rt and pain associated w ith continued p a r­ ticipation than d ealing w ith the p sy chological tension, anxiety a n d d e p re ssio n asso ciated w ith non-participation (smith et al, 1990b). it is logical to assum e that the stro n g er the a th le te 's preoccupation w ith health and fitness, the m ore intense these n egative m ani­ festations o f ex ercise d ep riv a­ tion w ill be. a nother phenom enon that m ust b e kept in m ind by the th erap ist, is the tendency o f m any a sportsm an to tie his identity and w orth as a person to his sports p articipation and sports achievem ents (joseph & r obbins, 1981). a signifi­ cant p a rt o f his d aily interaction w ith o th e r p eo p le is d o n e as a sportsm an. h e sees h im se lf as a sportsm an and o th e r p eo p le, treat him as such. w hen his sports particip atio n is tem po­ rarily o r perm an en tly disco n ­ tinued a loss o f identity can ---------------------------------------------- 5 sportsgeneeskunde vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychology occur. as a result it is not uncom m on for sportsm en to suffer a loss o f self-esteem w hen injured. e m o t io n a l r e a c t io n s t o in ju r y t here are suggestions that in ­ j u r e d s p o rts m e n p ro c e e d th ro u g h e m o tio n a l s ta g e s sim ilar to those experienced by the term inally ill. t he limited sports research that has been done on the so-called loss-of health m odels show s that these could be applied to som e extent to injured sportsm en. o gilvie and h ow e (1986) m aintain that sportsm en w ho are forced to term inate th eir athletic careers proceed through em otional stages sim ilar to those proposed by k iibler-r oss (1969). d enial is the first phase that the injured sportsm an enters. h e may deny the seriousness o f his injury and fail to accept the fact that he will be out o f action for an extended period o f tim e. this is also a com m on p h e­ nom enon am ong sportsm en w ho have to term inate their sporting careers for reasons o ther than injuries, for exam ple if they are no longer able to perform up to standard. a m anifestation o f this denial and unw illingness to accept the fact that they have com e to the end o f their sporting careers is an intensification o f physical training and an even m ore reg i­ mented lifestyle than before. h ow ever, not all sportsm en experience this phase. smith et al (1990a) observed em o ­ tional reactions am ong injured sportsm en sim ilar to that p ro ­ posed by k iibler-r oss but did not enco u n ter denial as a phase. t hey suggested that sportsm en w ho persist in play­ ing when injured do not deny pain as such, but are motivated to continue participating for m ore com plex reasons. w hen denial is no longer effective in dealing with the effects o f an injury, anger may ch aracterise the next stage. t he unfortunate aspect o f this stage is that anger and rage are often directed at those people w ho are close to the sportsm an, such as his fam ily, team -m ates and coach. this anger is often generalised to include g od, society, and life in general. a nger can also be directed inw ards. the injured sportsm an may becom e exces­ sively self-critical, blam ing him self for his condition. this anger may m anifest in self­ destructive b ehaviour such as alcohol and drug abuse. d uring this second stage the sportsman becomes irritable and difficult to w ork w ith. an o th e rw is e c o a c h a b le and reasonable person can becom e aggressive and negative. this stage could also be ch aracter­ ised by irrational thinking. the injured sportsm an can d isre­ gard im portant aspects o f his injury o r he can oversim plify the situation. a further form o f irrational thinking is o v erg en ­ eralisations and unw arranted conclusions. he may reason that because another person did not recover successfully, he will not succeed either. he may even conclude that the therapist and coach are not in ­ terested in his progress o r are not giving equal attention to his problem s. an understanding coach and therapist should approach such a person with a great deal o f em pathy and pa­ tience. a lthough the reactions o f denial and an g er may be in­ tense they are usually o f a short duration and the sportsm an moves into the next stage o f reactive depression. h e ty p i­ cally w ithdraw s and isolates him self. t his reaction is understandable because the sportsm an is confronted with a m ajor change in lifestyle. h e has invested a great deal o f his life in his sport and shows a type o f g rie f response (p ed­ ersen , 1986; w eiss & t ro x el, 1986). t h e sad aspect o f this reaction is that the athlete iso­ lates h im self from the social support o f im portant other people, w ho he in fact needs to help him on the road to recov­ ery. h e avoids his coach and team -m ates and experiences a feeling o f helplessness and loneliness in this situation that he has created him self. h is life may lose much o f the meaning it had b efo re his injury. if this condition persists o ver an ex ­ tended period o f tim e special counselling may be necessary (o gilvie & h ow e, 1986). a lthough the feeling o f iso­ lation is g enerally the result o f the sp o rtm a n 's own behaviour, som e coaches may contribute to this. c oaches may fail to keep in touch with the injured athlete o r fail to show a co n tin ­ ued and active interest in his progress. t h ere are even c o a c h e s w h o d e lib e r a te ly make the injured athlete feel w orthless in an attem pt to speed up his return to the playing field. it is not uncom m on for in­ ju re d sportsm en to experience feelings o f guilt. t hey may feel that they are letting their team and coach dow n. r uth­ less coaches may exploit the 6 ------------------------------------sports m edicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychology a th le te 's loyalty and co m m it­ ment to get him back on the field as soon as possible. t o counteract these feelings o f loneliness and isolation it is expedient that norm al co n ­ tacts should be resum ed as soon as possible. social sup­ port is a critical elem ent in enhancing treatm ent adherence (d uda et al, 1989; f isher, 1990). a ndersen and w illiam s (1988) propose that the p re s­ ence o f a supportive social netw ork (w hich includes the physician) may directly protect the sportsm an against injury o r may attenuate the effect o f the stress b rought about by daily hassles and the stressfulness o f com petitive sport. t h e in ju re d s p o rts m a n should rejoin his team as early as possible. a lthough it may be im possible to physically participate in p ractice ses­ sions, he can attend team discussions and scrim m ages. it is fu rth er suggested that he adopts a routined lifestyle sim ilar to that w hich he fol­ lowed p rio r to his injury. a k n o w le d g e o f th e em otional struggles o f the in­ ju red sportsm an can assist the coach and therapist in show ing greater em pathy. it is im p o r­ tant that this em pathy is co m ­ m unicated to the athlete. h e should be told that it is u n d er­ stood and accepted that the injury is inconvenient and that he feels disappointed, frus­ trated, im patient and at tim es angry. on the o th er hand, it should be pointed out to him that it is irrational to punish h im self and others. open a g ­ g r e s s io n to w a r d o t h e r s , especially those w ho are able to help him is not acceptable. it is also irrational to view his slow progress as a sign o f weakness. the final stage that follows injury is acceptance o f reality w ith the hope that som ehow ev erything will turn o ut for the best. l o c u s o f c o n t r o l locus o f control can play a s i g n i f i c a n t r o le in th e sp o rtsm an 's perception o f his injury and his rehabilitation. an internal locus o f control refers to the extent an individ­ ual believes that he has control o v er his life. in contrast, an external locus o f control is characterised by a perception that o n e 's life is controlled and d eterm ined by factors outside oneself, such as fate, luck, change and pow erful other people. t he individual with an external locus o f control feels gatorate t m i h t m u l m c h i n i \ r __________________________ 7 sportsgeneeskunde vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) psychology that he is helpless and does not have co n tro l o v er his ow n life. s portsm en gen erally have a strong internal locus o f co n ­ trol. it is th erefo re im portant that this locus o f control be m aintained durin g the reh ab ili­ tation p rocess. s portsm en w ho have em o ­ tional control will function more effectively i f they a re treated in a rational m anner. t hey will exert b etter control o v er th eir p rogress i f they a re provided w ith know ledge about their injury and the rehabilitation process. it has been estab ­ lished that adjustm ent p ro b ­ lem s in the rehabilitation o f cardiac patients is related to uncertainty about th eir co n d i­ tion (c hristm an, 1988). s im i­ larly, u n certainty could retard the rehabilitation o f the injured sportsm an. a p art from keep­ ing the athlete inform ed about his injury and his p ro g ress, it is suggested that the athlete is involved in the planning o f his rehabilitation. t h e process o f goal setting has relevance here. a lth o u g h th e in j u r e d sportsm an should b e involved in his ow n rehabilitation, f ish er (1990) w arns that the m otivation and adherence to persist w ith a rehabilitation p ro g ram m e is not the sole r e ­ sponsibility o f the person being treated. in fact, the attitude o f the therapist m ay be self-fu l­ filling. t he m o re nonad­ herence the therap ist expects the less he w ill be m otivated to chan g e the b eh av io u r o f the injured sportsm an if he p e r­ ceives the resp o n sib ility as being the p a tie n t's alone. this m otivation can b e reduced by failing (a) to adequately ex ­ plain the injury and proposed treatm ent, (b) to request the sp o rtsm a n 's assistance in the p ro g ram m e, (c) to m onitor p ro g ress, and (d) to m otivate the sportsm an w hen neces­ sary. conclusion w h ile m any sportsm en cope effectively w ith injury there are others w ho need special attention to adjust psychologi­ cally. an understanding o f the em otional reactions that follow an injury could lead to g reater em pathy w ith the sportsm an. social support, encouragem ent and the m aintenance o f norm al relationships could have a sig­ nificant effect on the reh ab ili­ tation process. k eeping the athlete inform ed about the n ature o f his injury and the p u r­ po se and p rogress o f reh ab ili­ tation could enhance recovery. r e fe r e n c e s 1. andersen mb and williams jm. a model o f stress and athletic injury: prediction and prevention. journal o f sport and exercise psychology, 1988; 10: 294-306. 2. bramwell st, masuda m, wagner nn and holmes th. psychological factors in athletic injuries. journal o f human stress, 1975; 2: 6-20. 3. carmen l, zerman jl, and bjgine gb. the use o f the harvard psychi­ atric service by athletes and non­ athletes. m ental hygiene, 1968; 52. 4. christman nj. uncertainty, coping and distress. research in nursing and health, 1988; 11, 71-82. 5. c oddingtonr d andt roxeljr . the effects o f emotional factors on foot­ ball injury rates: a pilot study. journal o f human stress, 1980; 7, 3-5. 6. cryan pd and alles wf. the rela­ tionship between stress and college football injuries. journal o f sports medicine, 1983; 23, 52-58. 7. d udajl , smart ae and tappe mk. predictors in adherence in rehabili­ tation o f athletic injuries: an appli­ cation of personal investment theory. journal o f sport and exercise psy­ chology 1989; 11, 367-381. 8. eldridge wd. the importance of psychotherapy for athletic-related orthopaedic injuries among adults. international journal o f sport psy­ chology, 1983; 14, 203-211. 9. fisher ca. adherence to sports injury rehabilitation programmes. sports medicine 1990; 9, 151-158. 10. joseph p and robbins jm . worker o r runner? the impact o f commit­ ment to running and work on self identification. the psychology o f running, 1981; pp. 131-145. mh sacks and m sachs (eds.). cham­ paign, 1l: human kinetics. 11. kerr g and minden h. psychologi­ cal factors related to the occurrence o f athletic injuries. journal o f sport and exercise psychology. 1988; 10, 167-173. 12. kiibler-ross e. (1969). on death and dying. new york: macmillan. 13. linder de, pillow dr, reno rr. shrinking jocks: derogation o f ath­ letes who consult a sports psycholo­ gist. journal o f sport and exercise psychology, 1989; 11, 270-280. 14. little jc. neurotic illness in fitness fanatics. psychiatric annals, 1979; 9, 148-152. 15. miller tw , vaugh mp and miller jm . clinical issues and treatment strategies in stress-oriented athletes. sports medicine, 1990; 9, 370-379. 16. ogilvie bc and howe m. the trauma o f termination from athletics. a p­ plied sport psychology. jean m. williams (ed.). 1986; pp. 365-382. palo alto, ca: mayfield. 17. passer mw and seese md. life stress and athletic injury: examina­ tion of positive versus negative events and three moderator variables. journal o f human stress, 1983; 10, 11-16. 18. pedersen p. the grief response and injury: a special challenge for ath­ letes and athletic trainers. athletic training, 1986; 21, 312-314. 19. pierce ra. athletes in psychother­ apy: how many, how come? jour­ nal o f the american college health association, 1969; 17, 244-249. 20. rotella r and heyman sr. stress, injury, and the psychological reha­ bilitation o f athletes. applied sport psychology. jean m. williams (ed.). 1986; pp. 343-364. palo alto, ca: mayfield. 21. sachs ml. psychological well-being and vigorous physical activity. psy­ chological foundations o f sport, 1984; pp. 435-444. jm silva 111 and rs weinberg (eds.). champaign, il: human kinetics. other references on request. 8 ----------------------------------sports m edicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cmucket cricket injuries a review richard stretch r eview s o f sporting injuries h av e tended to co n cen trate on con tact sports, w ith reports and research on cric k et injuries receiving little attention, mainly being conducted as p a rt o f oth er analysis and being p u b ­ lished in m edical jo u rn als. this has resulted in the m ajority o f cricket ad m in istrato rs, coaches and players n ot bein g aw are o f the nature, incidence, cause and risk factors associated with p laying a gam e that is d em an d ­ ing m o re physical o u tput than p rev io u sly . it w as fo r this reason that a review o f crick et injuries was conducted. t h e b ritish s ports c ouncil estim ated the risk o f injuries to club crick et players to be 2 ,6 p e r 10 000 man hours p la y e d .12 t h ese figures excluded inju­ ries thought to b e triv ial, as w ell as m any ch ro n ic o v eru se injuries. t h e rate o f injury to first class crick eters in a u stra­ lia w as estim ated to b e 1 p e r 30 m an-hours p la y e d .3 south a f­ rican p rovincial and in tern a­ tional crick eters (7 1 ,6 % ) w ere found to b e at a g reater risk o f richard a stretch ma d epartm ent o f human m ovement studies university o f fort hare private bag x i 314 ciskei injury than club cricketers (2 8 ,4 % ) .4 d eaths from crick et date b ack , according to crick et lo re, to the passing o f f red erick l ouis, the p rin ce o f w ales and father o f g eorge iii, w ho died hours afte r being struck on the head by a crick et b a ll.2 b lonstein5 suggests that six d eaths p e r y ear o ccu rred in the u nited k ingdom as a result o f playing cricket. however, these figures should b e considered w ith reserv atio n .3 t h e m ajor portion o f serious injuries w ere sustained during m atches (6 9 ,3 % ), with 2 6 ,1 % occurring during practices and 4 ,6 % during both m atches and p ractices.4 t he injuries o ccu r­ red fairly regularly th roughout the season, with a slight in ­ crease durin g the early and latter p a rt o f the season,4 o v e r­ use injuries m ore com m on to ­ w ards the end o f the seaso n .6 t h e incident o f injury to the head, neck and face varied from 9 % in club and provincial p la y e rs,4 20% in provincial players7 and 25 % in club c ric k ­ e te rs.2 c oncussions, co n tu ­ sions, lacerations and nose bleeds w ere the m ost com m on. e ye injuries in crick et w ere reported as long ago as the beginning o f the c e n tu ry ,8 with later cases o f ch ro n ic glaucom a secondary to traum a9 and o cu ­ lar concussion,10 reported. f ive cases o f severe eye injuries, including retina detachm ent and ru p tu re o f the globe, w ere d ocum ented in batsm an and close fie ld e rs .11 this accounted fo r 9 ,0 % o f sport related ey e injuries. a survey o ver 18 m onths carried o u t at the sussex e y e h osp ital revealed five m inor ey e injuries caused by playing c rick et w hich ac­ counted fo r 5 ,4 % o f all sport­ ing ey e in ju ries re c o rd e d .12 c o ro n eo 13 recom m ended that o cu lar p ro tectiv e devices be w orn when playing indoor crick et after rep o rtin g four cases o f o cu lar inj uries in crick­ eters. t he u pper lim b accounted fo r 25% o f injuries in club cric k e te rs,2 32% in provincial crick eters7 and 34% in pro v in ­ cial and club cric k e te rs.4 t he fingers w ere found to b e the m ost v u ln erab le site fo r inju­ ries. 1-2-4-6'14-15 t h ese injuries consisted prim arily o f fractures, dislocations and contusions w hile batting and fielding. "t h ro w ers shoulder" w hich is caused by degeneration and inflam m atory changes o r p a r­ tial and co m p lete ru p tu res o f the ro tato r c u f f w as also found to b e a co m m o n crick et in­ j u r y , 16 w hile c lay s h o v eller's fractu re w as recorded as a re ­ sult o f playing c ric k e t.17 b ack and tru n k in ju ries ac­ counted for approxim ately 18% o f the serious and 14% o f the less serious in ju rie s.4,7 t h e c ase o f a splenic ru p tu re as a result o f being struck by a crick et ball w as re p o rte d .18 y oung fast bo w lers w ere found to b e v ul­ ---------------------------------------------- 9 sportsgeneeskunde vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket nerable to low er back injuries,19 w hile the case o f a young fast b ow ler w ho developed acu te p n eum om ediastinum and b ilat­ eral pneu m o th o races w hile p ractisin g fast bow ling w as re ­ p o rte d .20 m any injuries o ccu r in the lo w er lim bs d u e to im pact from the ball, stress injuries asso ­ ciated w ith rep etitiv e m ove­ m ents and o th e r injuries n o r­ m ally associated w ith field sports. t h e findings varied from 2 5 % ,2 30 % 7 and 3 8 % .4 t h e unusual case o f tw o b ro th ­ ers sustaining serious injuries in the sam e pre-m atch fielding practice session was d o cu ­ m en ted .21 t h e first sustained a m edial m eniscus injury which had to b e excised arth ro scopically and th e o th er a transverse fractu re o f the m iddle third o f th e fem ur. bow ling has been found to be the m ajor cau se o f injuries, varying from 38% in young schoolboy p la y e rs ,19 4 2 ,0 % in club and pro v in cial cricketers4 to 65 ,7 % in p rovincial cric k ­ e te rs.7 t h ese w ere found to be p re d o m in a n tly lo w e r b ac k in ju ries,4,7,19,22 m uscle tears, especially o f the hip flex o r, the ad d u cto r longus o f the leg and the rectus fem oris m u s c le s ,6,16 and o v er-u se in ju rie s.4'719,22 s erious in ju ries, m ainly to the low er b ack o f a nu m b er o f elite and ju n io r fast bo w lers, w ere caused by a com bination o f the forces a t fro n t foot im pact and a front-on bow ling a c tio n .19 spondylolysis w as found to be com m on in a ustralian fast b ow lers p laying first class c ric k e t.6 this in ju ry is d u e to a stress fractu re that occurs to the p arts interarticulans on the side oppo site the bow ling arm as a resu lt o f the rotation and extension o f th e back when b ow ling fast. s tress fractures a re com m on in fast bow lers and-occur prim arily in the meta­ tarsal bones, the fibula and tib ia .6 o ther com m on over-use in ju r ie s in c lu d e a b d o m e n m uscle te ars,6 shoulder inju­ r i e s , 7 ta lo tib ia l ex o sto ses, p atella r tendonitis6 and bruised heels and "shin sp lin ts".4,6,7 batting accounted for 17,1 % o f the injuries4 with m uscle pulls and im pact injuries being the m ost co m m o n .4,7 t h e m a­ jo rity o f head injuries w ere as a result o f being struck by the ball w hile attem pting to hook, by the ball deflecting o ff the top-edge o f the b at on to the head w hile playing a horizontal-bat stroke, o r as a resu lt o f being struck by the ball rearing o f f the p itc h .7 t h ese injuries w ere sustained w hile the batsm en w ere b at­ ting w ithout a helm et o r w ith a helm et w ith ear-pieces only, respectively and included co n ­ cussions, broken nose and cheek bones and lacerations, req u ir­ ing stitches around the eyes, mouth and chin. four o f the ey e injuries reported by jones and t u llo 11 w ere as a result o f the ball deflecting o f f the top ed g e o f the bat w hile hooking and striking the eye on the side o f the dom inant hand. t he d an g er o f a fracture, as a result o f being struck by the ball w hile batting, to the distal third o f the u ln ar, rib fractures and soft tissue in ju ries, especially to the u p p er leg, abdom en and tes­ ticles w ere rep o rte d .6 t h e top and m iddle-order batsmen w ere found to b e m ore susceptible to im p act injuries to the head, p h ­ alanges, m etacarpals and low er arm injuries than the low er o rd e r b atsm en ,7 w hile p ay n e3 rep o rts that bo w lers sustained m ost im p act injuries w hile b at­ ting. l o w er lim b injuries w ere m ainly ham string, quadriceps and c a lf m uscle pulls as a result o f running between the w icket.14 ,7 f ield in g and catching re­ sulted in 4 0 ,9 % o f the serious in ju ries w ith 63 ,9 % im pact in ­ ju rie s to the u pper lim b s.4 c o rrig an 6 reported three cases o f rup tu red spleens sustained w hen, attem pting to catch o r field a ball, they landed heavily on th eir left side. "t hrow ers shoulder" can p ro v e to be one o f the m ost troublesom e injury to cric k e te rs.6,22 f iv e, o u t o f n ine shoulder injuries sustained o ccu rred w hile field in g .7 t w en ty -fiv e p ercen t o f the serious injuries resulted in the p lay ers being o u t o f the g am e for m o re than tw enty-one days, w hile 4 7 ,8 % and 2 7 ,2 % w ere n ot ab le to p ractice o r play for betw een o n e and seven days and eig h t and tw enty-one d ay s, resp ectiv ely .4 in ju ries to the u pper and lo w er lim bs w ere the m ost serious in term s o f days m issed with n in e in ju ries to each region prev en tin g the players from playing for twenty o n e day s o r m o re.4 t h e upper lim b injuries to the club cric k ­ eters resulted in an av erag e o f fiv e days being lost to play, w ith a ran g e o f betw een 0 to fifty-six d ay s, w hile an average o f six days w ere lost to p lay as a resu lt o f in ju ries to the low er lim b s .1 t h e head and facial injuries1,4 and the back and trunk injuries4 gen erally enabled the crick eters to retu rn to the gam e w ithin seven to n ine days o f injury. t h e length o f recovery tim e v aried w ith the level at w hich the p lay ers com peted. m any o f the in ju ries sus­ 10 ---------------------------------sports medicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket tained w ere eith er re-occurring in ju ries from the p rev io u s sea­ son o r re-o ccu rred again later in the season. t w enty p ercent o f the in ju ries sustained on an international to u r w ere re a g g r a v a te d in ju r ie s fro m the prev io u s seaso n ,23 w hile 2 3 ,9 % o f the injuries to b e re ­ o ccu rren ce o f old in ju ries and 22 ,7 % o f th e new in ju ries sus­ tain ed w e re re -a g g ra v a te d again durin g that season.4 p ayne3 reported an increase in o v er-u se in ju ries in young ch ild ren , especially in the areas o f stress fractures and grow th cartilag e injuries. t h e p rim ary areas o f concern, p articularly to the fast bow lers, w ere found to be dam age to the grow th cartilag e o f the knee and trac­ tion apophysis, and co m p res­ sive stress to the articu lar surface cartilag e o f the fem ur and talus. t h irty -eig h t percen t o f young fast b o w lers w ere found to have suffered o n e d is­ abling injury durin g a single season, w ith stress fractures o f the lu m b ar an d /o r sacral v e r­ tebrae (11% ), and soft tissue injuries to the back (27 %) cau s­ ing them to m iss at least one m a tc h .19 d u t oit and r ade m an18 reported the case o f a 1 4 -y ear-o ld b o y re q u irin g splenectom y fo r a ruptured spleen after b lunt trau m a from a crick et ball. t he case o f a y o u n g f a s t b o w le r w h o developed acu te p n eu m o m e­ diastinum and bilateral pneu m othoraces w hile p ractising fast b ow ling w as reported by c lem ents and h a m ilto n .20 t he y o u n g er p lay ers tended to b e at the greatest risk to injury with 53 ,3 % and 5 1 ,4 % o f th o se in the age gro u p s below 21,1 years and betw een 21,1 and 2 6 ,2 years, respectively, sus­ taining som e form o f serious in ju ry .4 t h e less serious injuries were mainly strains o f the groin, hip, ham string, quadriceps and back m uscles, finger injuries, tw isted ankles, shin splints, blisters, abrasions and bruised feet, heels and fingers. f o rw a rd 24 recorded all the ind o o r cricket injuries that w ere reported at the r oyal p erth h ospital d u ring a six m onth perio d . h e found that o f the sixty-four patients treated all fell in the 19 34 y ear age gro u p , w ith fourteen o f these being w om en. f ield in g (72% ) and batting (17% ) resulted in the m ajor share o f these in ­ ju rie s , w hile no injuries w ere sustained w hile b ow ling. t h e m ost com m on injuries w ere to the fingers and thum b. k nee and ligam entous strains o f the ankle w h ile tw isting to catch o r avoid the ball, as w ell as ey e in ­ ju rie s to w icket-keepers as a result o f being struck by the ball after deflecting o f f the edge o f the bat, w ere fairly co m ­ mon. f ifty p ercen t o f the in ­ ju re d players required tim e o f f w ork, w ith thirty p ercent being o f f w o rk fo r m o re than a w eek and ten percen t being hospital­ ised. f ro m the literatu re re ­ view ed it is evident that the incidence o f crick et injuries, p articu lar o v er-u se injuries and those norm ally associated w ith field sports, is an under recognised p roblem . a ppro­ p riate injury records and d ata collection need to be introduced. this w ould enable coaches, players and those involved in treatm ent and rehabilitation, to successfully bring about the reduction, p revention, trea t­ m ent and rehabilitation o f these injuries. re f e r e n c e s 1. weightman d and browne rc. in­ juries in eleven selected sports. british journal o f sports medicine, 1971; 2: 27. 2. temple r. cricket injuries: fast pitches change the gentleman's sport. the physician and sports medicine, 1982; 10(6): 186-192. 3. payne w r , h oy g , laussen sp and carlson js. what research tells the cricket coach. sports coach, 1987; 10(4): 17-22. 4. stretch ra. somatotype and body composition changes in first-class cricketers. paper presented at "inter­ national congress on youth, lei­ sure and physical activity and ki nanthropometry iv", brussels, bel­ gium, 21-25 may 1990. 5. blonstein jl. medical aspects o f am ateur boxing. proc r soc med, 1966; 59: 6499. 6. corrigan ab. cricket injuries. aus­ tralian family physician, 1984; 13(8): 558-562. 7. stretch ra. injuries to south afri­ can cricketers playing at first-class level. sports medicine, 1989; 4(1): 3-20. 8. ogilviefm . on one o f the results of concussion injuries o f the eye ("holes" at the macula). trans opthalmol soc uk, 1900; 20: 202-229. 9. d 'o m brain a. traumatic monocu­ lar chronic glaucoma. trans optha m ol soc, australia, 1945; 5: 116 120. 10. littlewood kr. blunt ocular trauma and hyphaema. australian journal o f ophthalmology, 1982; 10: 263 266. 11. jones np and tullo ab. severe eye injuries in cricket. british journal o f sports medicine, 1986; 20(4): 178 179. 12. gregory pts. sussex eye hospital sports injuries. british journal o f ophthalmology, 1986; 70: 748-750. 13. coroneo mt. an eye for cricket ocular injuries in indoor cricketers. the m edical journal o f australia, 1985; 142: 469-471. 14. nel d, smit pj and stoker dj. die invloed van sportsbeserings op sportdeelname en werk. south afri­ can m edical journal, 1979; 53: 426 428. 15. williams jgp. joint injuries. in: i cohen, gr beaten and d mitchell (eds). the south african textbook o f sports medicine, university of witwatersrand, johannesburg, 1979. other references on request. --------------------------------------------- 11 sportsgeneeskunde vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s3] relifen 500 tablets 500 m g n a b u m e t o n e . r e e n o r / 3 . 1/265 w h en y o u r p a tie n t’s in pain, y o u r first responsibility is to take aw ay th a t pain. q u ick ly . effectively. b ut doing so could lead to unacceptable gastro­ intestinal side effects and co m b in atio n th erap y . b ut n o w , ten years o f precisely targeted m o lecular research have p ro d u ced a h ighly effective, no n-acidic an ti-in flam m a to ry . relifen. each tablet is m ade o f 500 mg n ab u m eto n e, a n o n -stero id a l an ti-in flam m ato p ro v en in n u m e ro u s d o u b le blind studies to b effective as o th e r b en ch m ark n s a id s. yet its ro u te o f action is to tally different. relifen is a n o n-acidic p ro -d ru g . in the sto m ach , it is relatively inactive. it is absorbed fro m the d u o d e n u m , into the p o rtal b lood suf f inally, in the liver, it is m etabolised into a po in h ib ito r o f p ro stag lan d in synthesis. r efer package in sert f o r full p re s c rib in g in fo rm a tio n . f u r th e r in fo rm a tio n is available fro m o u r m edical d e p a r tm e n t. s m ith k lin e b eecham p h arm a ceu ticals p o box 347 be r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) relieving his pain is pretty sporting of you, old chap. but do you have to get him high on acid? t h e active m etab o lite p en etrates th e synovial fluid to reach th e inflam ed site, giving effective relief of sy m p to m s. e x cretio n is by the kid n ey s, so g astro ­ intestinal dam age th ro u g h biliary recircu latio n and reflux is unlikely. f o r effective relief from pain and inflam m ation, with less chance of gastro -in testin al d isco m fo rt, y o u now have an ideal choice. relifen. r clilen a n d th e sb lo g o a rc tra d e m a rk s . r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutktfuqn the effect of dietary cholesterol on plasma cholesterol levels m ieke faber eggs, and th erefo re d ietary ch olesterol, play an im portant ro le in the diets o f m any a th ­ letes. e specially w eight train ­ ing athletes are p ro n e to sup­ p lem ent th eir diets w ith eggs in o rd e r to in crease the protein con ten t o f the diet. since as early as the 1 9 4 0 's the co n tro v ersy on cholesterol intake exists. in the 1 9 4 0 's experim ents w ere d o n e w hich show ed that cholesterol feed­ in g re s u lte d in in c re ased p la sm a c h o le ste ro l le v e ls .29 h o w ev er, a few years later k eys et al (1956) cam e to the conclusion that in adult men the serum cholesterol level is es­ sentially independent o f the cholesterol intake o v er the w hole ran g e o f natural hum an d ie ts.22 t his w as confirm ed by studies that indicated that there w as no co rrelatio n b e­ tw een d ietary cholesterol and plasm a cholesterol le v els.25,40 a lthough no co rrelatio n w as found betw een w h o le egg in­ take and plasm a lipid levels in free living su b jects,19 contromieke faber research institute f o r nutritional diseases m edical research council versial results h av e been re ­ p orted on the effect o f egg feeding. w h ile no changes in plasm a cholesterol levels w ere observed after the addition o f e g g s to th e h a b i tu a l d ie t17,23,33,36,38 o r an exp erim en ­ tal d ie t15 o f norm al o r uraem ic p atien ts,20 o th er studies re ­ p o rted an in crease in plasm a cholesterol levels after egg fe e d in g o n th e h a b itu a l d ie ts 3-35-39 o r ex p e rim e n ta l diets28 o r on liquid form ula d ie ts .1 t h e increase in plasm a cholesterol levels w as g reater in m iddle aged m en as co m ­ p ared to y ounger m e n .39 v olunteers w ere g rouped in tw o groups. t h e one group show ed significant increases in plasm a cholesterol levels a fte r eating th ree eggs daily for ten w eeks and a significant decrease w ithin tw o w eeks o f cross o v er to eating no eggs. t h e o th er g ro u p show ed a sig­ nificant d ecrease in plasm a cholesterol levels after eating no eggs for 12 w eeks, b ut w hen crossing o v er to three eggs daily, there w as no increase in plasm a cholesterol le v e ls.18 f ifty -six men w ere given a cholesterol free fo rm u la diet. d u rin g this p erio d there w as a d ecrease in plasm a cholesterol levels. a fter the cholesterol free p eriod they w ere divided into fo u r groups w ho received a fo rm u la d iet containing either 0, 106, 212 o r 317 mg ch o l/ 1000 kcal fo r a p erio d o f six w eeks. t h e ingestion o f ch o ­ lestero l resulted in a lin ear in crease in p lasm a cholesterol levels o v er the w h o le ran g e o f cholesterol feeding. each 100 m g c h o l/1000 kcal o f the diet resu lted in a 12 m g /100 m l in­ crease in serum cholesterol lev els.27 it is expected that fu rth er increases in dietary cholesterol in the ab o v em en ­ tioned study w ould have no fu rth er effect on the plasm a cholesterol levels since it w as show n by c o n n o r et a l10 that the addition o f 475 mg o r 1425 mg cholesterol had the sam e elevating effect on plasm a cholesterol levels. it has also been show n that the plasm a cholesterol levels increased sharply w hen the daily choles­ tero l intake w as betw een 13 mg and 634 m g. t h ere w as no fu rth er in crease in plasm a ch o ­ lesterol levels a fte r the inges­ tion o f 1300 to 4 5 0 0 m g choles­ tero l and th e dose-response cu rv e w as relativ ely fla t.2 a ddition o f tw o eggs had no effect on p lasm a cholesterol levels, b ut w hen the tw o eggs w ere rem oved from the diet th ere w as a significant d ro p in plasm a cholesterol levels afte r 12 w e e k s .16 w hen eggs w ere rem oved from the diets o f 14 ---------------------------------------sports m edicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition p eo p le w ho h abitually consum e at least o n e egg p e r day, there w as a sm all b u t significant d e­ c rease in p lasm a cholesterol le v els.4’7 effect of dietary cholesterol on plasma lipoproteins p lasm a cholesterol is not the only v ariab le to b e looked at. a lthough th ere w as no signifi­ c a n t c h a n g e in p la s m a cholesterol levels w hen one egg w as added to the habitual d iet o f lacto-ovo-vegetarians, th ere w as a significant increase in p lasm a l d l -ch o lestero l.36 w h ile ingesting a liquid fo r­ m ula d iet containing 5000 mg cholesterol in the form o f egg y o lk 1 o r w hen adding choles­ terol to the norm al d iet3 there w as a significant in crease in p la sm a c h o le ste ro l le v els, m ainly d u e to an increase in l d l -ch o lestero l levels. t he rise in l d l -ch o lestero l levels m ay be explained by an in­ crease in l d l -ch o lestero l fo r­ m a tio n .30 t h e consum ption o f a larg e n u m b er o f eggs, w h eth er o r not it leads to an in crease in plasm a cholesterol levels, does alter the p ro p erties in hum an h d l , nam ely it in ­ creases the binding cap a c ity .26 type of fat in the diet it has been show n that the e f­ fect o f d ietary cholesterol is dependent on the type o f fat in the diet. in tw o cross o v er studies, healthy students re­ ceived a d iet eith er rich in linoleic acid5 o r p o o r in linoleic a cid 6 w ith tw o levels o f d ietary cholesterol (eith er 200 mg o r 600 m g). t h e high cholesterol diet w as obtained by providing 2 egg yolks p e r day. s upple­ m entation o f the linoleic acid rich d iet w ith th e egg yolk cholesterol caused a signifi­ cant rise in plasm a cholesterol levels o f about 11 m g /100 ml. this rise in plasm a cholesterol w as ho w ev er m uch sm aller than the rise o f 26 m g /100 ml w hich o ccurred w hen the lino­ leic acid p o o r diet w as supple­ m ented w ith the egg y olk cholesterol, indicating th at the effect o f cholesterol is clearly dependent on the type o f fat in the d ie t.5,6 w hen cholesterol w as added to eith er a diet w ith a low o r a high p /s ra tio n , th ere w as an increase in plasm a t c . t h e increase in plasm a ch o les­ terol w as slightly less on the low p /s d iet as com pared to that on the high p /s diet, b u t it should be kept in m ind that the o v e ra ll p la sm a c h o le ste ro l levels (w ith o r w ithout ch o les­ terol) w ere h ig h er on the d iet w ith the low p /s ratio .41 in an o th er cross o v er study, the effect o f changes in dietary cholesterol in tak e as w ell as changes in the type and am o u n t o f fat w as studied. w hen the subjects sw itched from a co n ­ trol d iet (42-45% fat, p /s 0 ,3 -0 ,5 , 2 eggs) to a fat m o d i­ fied d iet (35% fat, p /s 1,0) also containing tw o eggs, the serum cholesterol decreased w ith 29 m g /100 ml. w hen the eggs w ere om itted from th e fat m odified d iet the serum ch o ­ lesterol decreased w ith an additional 7 m g /100 ml. w hen the control d iet w as follow ed up by the m odified fat d iet co n ­ taining no eggs, the d ecrease in serum cholesterol levels w as 41 m g /100 m l. w hen eggs w ere returned to the fat m odified d iet, th e serum cholesterol levels increased by 2 0 m g/100 m l. t h e results o f this ex peri­ m ent suggest that sm aller p ercen tag e changes in the type and am o u n t o f d ietary fat have a sim ilar o r g reater effect on serum cholesterol than a re la­ tively g reater change in dietary ch o lestero l.8 t h is is in contrast w ith earlier studies. in one o f these studies it w as shown that the effect o f changes in d ietary fat com position w as sm aller than th e effect caused by changes in d ietary choles­ te ro l.12 p lasm a cholesterol level increased w hen subjects con-sum ed a cholesterol rich fo rm u la diet. w hen th e satu­ rated fat co n ten t o f this d iet w as decreased, there w as no ch an g e in the p lasm a choles­ tero l levels d u e to cholesterol feeding.11 although no changes in h d l -c w ere found in the study d o n e by c h en o w eth ,8 it w as found that the increase in plasm a cholesterol w hich o c­ cu rred a fte r a sim ultaneous increase in d ietary cholesterol and fat, w hile the p /s ratio o f th e d iet rem ained the sam e, w as du e to an in crease in ld l c as w ell as h d l -c .9 e ith er 750 mg (3 eggs) o r 1500 mg cholesterol (6 eggs) w as added to diets w ith a p /s ratio th at ranged betw een 0 ,2 5 and 2 ,5 . w hen the p /s ratio w as eith er 0 ,2 5 o r 0 ,4 , addition o f 3 eggs to th e d iet caused increases in b o th p lasm a cho­ lestero l and l d l -c levels. t h e se in c re a se s w ere in ­ creased fu rth er w hen 6 eggs w ere added to the diet. w hen the p /s ratio o f the d iet w as 0 ,8 , addition o f 3 eggs to the d iet had no effect on plasm a cholesterol o r l d l -c levels, b u t these levels increased after addition o f 6 eggs to the _______________________________ 15 sportsgeneeskunde vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition diet. a ddition o f eith er 3 eggs o r 6 eggs had no effect on the p lasm a cholesterol and l d l -c levels w hen the p /s ratio o f the d iet w as 2 ,5 . t his study indicated that both th e choles­ terol con ten t and the p /s ratio o f the d iet are im p o rtan t in de­ term ining p lasm a cholesterol and l d l -c lev els.37 f a t p lays and im p o rtan t ro le in determ ining the effect o f dietary cholesterol on plasm a cholesterol levels and has been dem onstrated by the fact that subjects w ho have previously b een cla ssifie d as h y p e r­ responders show ed no re ­ sponse to a m oderate choles­ terol intake w hile they co n ­ sum ed a low fat, high fib re diet w ith a relatively high p /s ratio (1 ,1 :1 ,5 ). t h e effect o f eating nine, zero and nine eggs p e r w eek o v er a p erio d o f three c o n s e c u t iv e m o n th s w a s studied in subjects w ho had previously been classified as hy per-responders to choles­ terol intake. d u rin g the study they consum ed a high fibre, low fat diet w ith a relatively high p /s ratio. t h ere w ere no s ig n ific a n t d iffe re n c e s b e ­ tw een the d ifferen t dietary periods indicating that h y p er­ response to m o d erate choles­ terol in tak e is no t app aren t in peo p le eating a low fat, high fib re d ie t.13 energy and cholesterol feeding it seem s as i f n o t only the type and am o u n t o f fat in the diet have an effect on the plasm a cholesterol response on c h o ­ lesterol feeding, b u t energy intake also seem s to b e im p o r­ tant. t h e influence o f a low energy d iet w hen associated w ith a high cholesterol intake w as investigated in a cross o v e r study. w hen tw o w hole eggs and tw o egg yolks w ere added to the habitual d iet o f seventeen norm al men during the first phase o f the study, no changes in p lasm a cholesterol o ccurred. w hen these sam e men w ere p u t on a low -energy d iet during the second p h ase o f the study there w as only a sm all b u t insignificant de­ crease in p lasm a cholesterol levels due to adaptation to a high cholesterol intake. h o w ­ ever, w hen the consum ption o f fo u r eggs p e r day w as associated w ith a low energy intake during p hase 1, there w as an increase in plasm a cholesterol levels w hich n or­ m alized in the second p a rt o f the study w hen they returned to th e ir habitual energy in ­ ta k e .24 exercise and cholesterol feeding it seem s as if ex ercise also in­ fluences the effect o f choles­ terol feeding on plasm a ch o ­ lesterol levels. it has been shown that aerobic co ndition­ ing in men m ight p rev en t a significant increase in plasm a t c levels at m oderate and high cholesterol in tak es.34 body b u ild ers are a g roup o f w eight training athletes w ho supple­ m ent th eir diets w ith eggs. o ver a range o f from 0 to 12 eggs p e r day, th ere w as no correlation betw een egg intake and plasm a cholesterol levels. d espite th eir v ery high choles­ terol intake they did not have elevated plasm a cholesterol le v e ls.14 hypoand hyper­ responders t h ere w as a co nsiderable in d i­ vidual variation in the response o f plasm a cholesterol levels to changes in dietary choles terol.8’15'18’23,31’41 from this wide v ariation it is clear that people can b e categorized into h y p er­ r e s p o n d e r s a n d h y p o -re sponders. w hat the classifi­ cation o f a hyperand a hypo resp o n d er is, is n ot q uite clear. in the study done by o h and m ill e r 31 h y p e r r e s p o n d e r s w ere defined as those subjects w h o se p la sm a ch o le ste ro l levels increased by m o re than 8% on cholesterol feeding, w h ile hyp o -resp o n d ers w ere defined as th o se subjects w ho show ed no change o r an in ­ crease o f less than 5 % in plasm a cholesterol levels on choles­ terol feeding. h y p er-resp o n d ­ ers can also be classified as those subjects w hose plasm a cholesterol levels a re in the u p p er q u artile on cholesterol feeding w h ile hypo-respon­ ders are those w hose plasm a t c levels fall in the low er q u artile on cholesterol feed­ in g .21 a lthough it seem s as if ex ercise has a p ro tectiv e effect against egg fee d in g ,14,34 too little ev idence is available to ju stify the high egg consum p­ tion o f athletes. it is reco m ­ m ended that athletes follow the sam e recom m endations as the g eneral po p u latio n . it is th erefo re recom m ended that the daily cholesterol intake should not exceed 300 mg p e r d a y .32 r e fe r e n c e s 1. applebaum-bowden a, hazzard wr, cain j, cheung m c, kushwaha ra, 16 ______________________ sports m edicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m j t m t e o n albers jj. short term egg yolk feeding in humans. atherosclerosis, 1979; 33: 385-396. 2. beverdige jmr, connell wf, mayer ga, haust hl. the response o f man to dietary cholesterol. j nutro, 1969; 60: 61-65. 3. beyen ac, katan mb. e ffectofegg yolk feeding on the concentration and composition o f serum lipopro­ teins in man. atherosclerosis, 1985; 54: 157-166. 4. beyen ac, katan mb. reproduci­ bility of the variations between humans in the response o f serum cholesterol to cessation o f egg consumption. atherosclerosis, 1985; 57: 19-31. 5. bronsgeest-schoute dc, hautvast jgaj, hermus rjj. dependence o f the effects o f dietary cholesterol and experimental conditions on serum lipids in man. i: effects o f dietary cholesterol in a linoleic acid-rich diet. am j clin nutr, 1979; 32: 2183-2187. 6. bronsgeest-schoute dc, hermus rjj, dalinga-thie gm, hautvast jgag. dependence o f the effects o f dietary cholesterol and experimental condi­ tions on serum lipids in man. ii: effects o f dietary cholesterol in a li­ noleic acid-poor diet. am j clin nutr, 1979; 32: 2188-2192. 7. bronsgeest-schoute dc, hermus rjj, dallinga-thie gm, hautvast jgaj. dependence o f the effects o f dietary cholesterol and experimental condi­ tions on serum lipids in man. ill: the effect o f serum cholesterol o f re­ moval o f eggs from the diet o f free living habitually egg-eating people. am j clin nutr, 1979; 32: 2193 2197. 8. chenoweth w, ullmann m, simpson r, leveille g. influence o f dietary cholesterol and fat on serum lipids in men. jn u tr, 1982;111:2069-2080. 9. cole tg, patsch w, kuisk i, gonen b, schonfeld g. increases in dietary cholesterol and fat raise levels o f apoprotein e-containing lipoproteins in the plasma o f man. j clin endo crinalm etab, 1983; 56: 1108-1115. 10. connor we, hodges re, bleiler re. the serum lipids in men receiv­ ing high cholesterol and cholesterol free diets. j clin invest, 1961; 40: 894-901. 11. connor we, hodges re, bleiler re. effect o f dietary cholesterol upon serum lipids in man. j l a b clin m ed, 1961; 57: 331-342. 12. connor we, stone db, hodges re. the interrelated effects o f dietary cholesterol and fat upon human se­ rum lipid levels. j clin invest, 1964; 43: 1691-1696. 13. eddington jd, geekie m, carter r, benfield l, ball m, mann j. serum lipid response to dietary cholesterol in subjects fed a low-fat, high fibre diet. am j clin nutr, 1989; 50: 58 62. 14. faber m, benade ajs, van eck m. dietary intake, anthropometric meas­ urements and blood lipid values in weight training athletes (body build­ ers). int j sports med, 1986; 7: 342 346. 15. flaim e, ferreri lf, thye fw, hill je, ritchey sj. plasma lipid and lipoprotein cholesterol concentrations in adult males consuming normal and high cholesterol diets under controlled conditions. am j clin nutr, 1981; 34: 1103-1108. 16. flynn ma, anderson a, rutledge m, nolph gh, krause g, ellersieck mr. eggs, serum lipids, emotional stress and blood pressure in medical students. arch environmental health, 1984; 39: 90-95. 17. flynn ma, nolph gb, flynn tc, kahrs r, krause g. effect o f dietary egg on human serum cholesterol and triglycerides. am j clin nutr, 1979; 32: 1051-1057. 18. flynn ma, nolph gb, osio y, sun gy, lanning b, krause g, dally jc. serum lipids and eggs. j am diet assoc, 1986; 86: 1541-1548. 19. green ms, jucha e. association o f serum lipids with coffee, tea, and egg consumption in free-living sub­ jects. j epidemiol comm health, 1986; 40: 324-329. 20. green em, perez go, hsia sl, c rary m . effect o f egg supplement on serum lipids in uraemic patients. j am diet assoc, 1985; 85: 355-357. 21. katan mb, beyen ac, de vries jhm, nobels a. existence o f con­ sistent hypoand hyper-responders to dietary cholesterol in man. am j epidemiol, 1986; 123: 221-234. 22. keys a, anderson jt, m ickelseno, adelson sf, fidanza f. diet and serum cholesterol in man: lack of effect o f dietary cholesterol. j nutr, 1956; 59: 39-56. 23. kummerow fa, kim y, hull, pol­ lard j, hinov p, dorossiev dl, valek j. the influence o f egg consumption on the serum cholesterol level in human subjects. am j clin nutr, 1977; 30: 664-673. 24. lacombe cr, corraze gr, nibbe link mm, boulze d, douste-blazy p, camare r. effects o f low-energy diet associated with egg supplemen­ tation on plasma cholesterol and lipo­ protein levels in normal subjects: results o f a cross over study. br j nutr, 1986; 56: 561-575. 25. liebman m, bazzarre t. plasma lipids o f vegetarian and non-vegetar­ ian males: effect of egg consump­ tion. am j clin nutr, 1983; 38: 612 619. 26. mahley rw, innerarity tl, bersot t p, lipson a, margolis s. altera­ tions in human high density lipopro­ teins, with or without increased plasma cholesterol induced by diets high in eholesterol. lancet, 1978; 11: 807 809. 27. mattson fh, erckson ba, kigman a m . effect o f dietary cholesterol in man. am j clin nutr, 1972; 25:589 594. 28. m cm urrym p, connor w e, lin ds, c erqueiram t , connor sl. the ab­ sorption o f cholesterol and the sterol balance in the tarahumara indians o f mexico fed cholesterol-free and high cholesterol diets. am j clin nutr, 1985; 41: 1280-1208. 29. m essinger wj, porowska y, steele jm. effect o f feeding egg yolk on serum cholesterol levels. arc int med, 1950; 86: 189-195. 30. nestel pj, billington t. increased transport o f intermediate density lipoprotein (idl) with cholesterol loading. metabolism, 1983;32:320 322. 31. oh sy, miller lt. effect o f dietary egg on variability o f plasma choles­ terol levels and lipoprotein choles­ terol. am j clin nutr, 1985; 42: 421-431. 32. o p't h of l. consensus symposium: dietary recommendations for the prevention o f coronary heart dis­ ease. s a fr m ed j, 1988; 74: 475 476. 33. porter mw, yamanaka w, carlson sd .flynnm a . effect o f dietary egg on serum cholesterol and triglyc­ eride o f human males. am j clin nutr, 1977; 30: 490-495. 34. quig dw, thye fw, richey sj, herbert wg, clevidence ba, rey­ nolds lk, smith mc. effects o f short term aerobic conditioning and high cholesterol feeding on plasma total and lipoprotein levels in seden­ tary young men. am j clin nutr, 1983; 38: 825-834. 35. roberts sl, mcmurry mp, connor we. does egg feeding(i.e. choles­ terol) affect plasma cholesterol lev­ els in humans? the results o f a double-blind study. am j clin nutr, 1981;34:2092-2099. 36. sacks fm, salazar j, miller l, fos­ ter jm , sutherland m , samonds kw, albers jj, kass eh. ingestion of egg raises plasma low density lipo­ proteins in free-living subjects. lan­ cet, 1984; 1: 647-649. □ ---------------------------------------------17 sportsgeneeskunde vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasma update sasma news t he 4th south a frican sports m edicine c ongress heralded a new era for sport in south a frica. all indications are that south a frica will be allow ed to p articipate at international level again after years o f isola­ tion. t his places a big respon­ sibility on sportsm en and coaches and also dem ands p ro p er m edical care fo r o u r athletes to en su re that their preparation and participation are scientifically sound and that adequate care is being taken to prevent, treat and re h a b ilita te sp o rt in ju ries. m edical schools in south a frica have lagged behind the rest o f the com peting w orld in providing adequate p o st­ g r a d u a te s p o r ts m e d ic in e training to doctors taking care o f athletes. d uring the past four years, the s outh a frican s p o rts m edicine a ssociation played a significant role in education and dissem ination o f know ­ ledge through the four s port m edicine c ongresses held in south a frica durin g the past eight years. n ot only did we create a forum w here young south a frican s ports m edicine scientists could present their research, but w e also invited leading s ports m edicine p h y ­ sicians from all co m e rs o f the w orld to address us on various im portant aspects o f sport and m edicine. t he m ost recent s ports m edicine congress in sun city from 24-27 a pril 1991 w as no exception: w e invited five in­ ternational speakers to address us on various topics. t h e sec­ retary g eneral o f the in tern a­ tional f ederation o f sports m edicine (fim s f ederation internationale m edico s p o r­ tive) attended o ur congress and announced that south a frica will be accepted as the 83rd m em ber o f this influential sports m edicine body. in o rd er to stage in ter­ national sports events in ou r country, we need to have an accredited analytic laboratory for doping control. since south a frica has been active in this field since 1983 under the g uid­ ance o f one o f the w o rld 's best known doping control labora­ tories at k in g 's c ollege in l on­ don, it will only be a form ality to obtain international accred i­ tation for o u r doping control facilities. w e had the good fortune o f having d r david c ow an o f london as one o f o ur distinguished guests to ev alu ­ ate o ur facilities and to advise us accordingly. d r c ow an is head o f the k in g 's c ollege doping control and information c entre in l ondon and will be instrum ental in advising the ioc medical commission about the south a frican situation. w e b e lie v e that s outh a frica will be ab le to accept the challenge o f providing ad e­ quate m edical support to ou r athletes. t he south a frican sports m edicine a ssociation succeeded in bringing together all the disciplines involved in sports m edicine and prom oting c o o p e r a tio n b e tw e e n th is m ulti-disciplinary team by making everybody concerned aw are o f their unique role. but this is not enough: south a frioa needs m ore sports m edicine training facilities to fulfil the needs o f o u r top sportsm en that will soon be co m p e tin g at in tern atio n al level. if the association suc­ ceeds in m aking south a frica m ore aw are o f o u r needs in this regard, it will be a m ajor achievem ent! □ 18 -----------------------------------sports m edicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) p iiy sio t iik k a pv treatment of soft tissue injuries: the facts about frictions c r a ig a s m ith keywords: soft tissue injuries, scarring, deep transverse frictions, physiotherapy. a b s t r a c t t he treatm ent o f soft tissue injuries by deep transverse frictions (d t f ) has been looked upon by various medical p ractitioners with a certain deg ree o f circum spect. a lthough m ost physiotherapists and a few physicians stringently advocate its use, there are still those w ho a re ignorant to its benefits. t his p aper attem pts to bring to attention the expediency o f d t f by providing a short overview o f how the technique achieves its curative effect. in t r o d u c t io n t h e history o f m assage dates back to the tim es o f ancient b abylonia, c hina and h isto ri­ cal r om an d a y s .1 g reat use for it w as found as an effective m ethod o f treating system ic illnesses and o th er injuries. n ow adays, m assage as we are fam iliar w ith, is used m ore for relaxation purposes and the re lief o f stress w hich stem s craig a smith bsc physiotherapy bsc (hons) sports science 16 vredenhof carstens road tam boerskloof cape town 8001 mostly from the lifestyles people lead. a lthough m as­ sage in this respect is very effective in creating a relaxed and calm ing, alm ost euphoric feeling, it clearly has no role to play in the treatm ent o f soft tissue injuries. t h ere is, how ever, a certain m assage technique with which physiotherapists and a good m ajority o f th eir patients are fam iliar. it proffers certain relief with most soft tissue injuries, providing the patient is able to b ear the excruciating pain which unfortunately goes hand in hand with it. w elcom e to the facts about frictions; deep transverse frictions! m ost medical practitioners, barring those who are athletes and w hose injuries have b en e­ fited from it in som e w ay, view d t f w ith a certain am ount o f scepticism and doubt. h ow can a m assag e tech n iq u e resolve an injury w hen it seems to be doing m ore dam age than good? how can the patient b enefit from such a treatm ent w hich actually causes m ore pain than the injury itself? how can any sensible medical per­ son ev er have co m e to devise such a method which should not even be regarded safe as a to rtu re technique? t h ere is, how ever, an answ er to this rhetoric and it lies with the com m ents o f those patients w ho have endured the pain, yet w itnessed the results when treated in this m anner: it works so i'll bear it. no pain no gain. d t f w as view ed as early as 1948 as the only w orthw hile m anipulative treatm ent which could ex ert a beneficial effect on soft tissue lesions. d r jam es c y riax 2 has cham pioned its cause for many years and now --------------------------------------- 19 sportgeneeskunde vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy it is w idely used by p h y sio th er­ apists and recom m ended by o ther p ractitio n ers in the treat­ m ent o f o rthopaedic and sports related in ju rie s.3-4 the theory of dtf t h e specificity o f d t f is such that w hen it is p erfo rm ed p ro p ­ erly and w ith sufficient vigor, enough to brin g the p atient to tears and g iv e reason to renam e it cru cifix io n s3, it p en etrates deep to affected structures far below the skin surface, w h ere o th er m odali­ ties w ould only ex ert their effect a t a superficial le v e l.1 it follow s that m assage, in this w ay, m ust be confined to tissues th at respond to it, and that it m ust ex ert its effect at the ex act site o f the lesio n .5 t h e aim o f this technique is tw o fold; p rim arily to b reak dow n adhesions o r fibrous scarring w hich develop durin g the bodies natural healing process follow ing an injury, and secondly, to increase the m obility o f those tissues and in so doin g , im p ro v e th eir func­ tional capacity. d t f is thus in ­ dicated in the treatm en t o f m uscle strains and tears, ten ­ don le sio n s (te n o sy n o v itis and tendonitis) and ligam ent sprains. application of dtf d t f is applied only to the area o f injury w ith firm p ressu re across th e g rain o f the tissues, b e it a sm all concentrated spot o r a longitudinal p a rt o f a m u scle.6 t h e effects w hich p ro m o te a healing response are as follow s: • a traum atic hyperaem ia is p roduced follow ing a couple o f m inutes o f d t f . t h e increase in bloody supply affords a deg ree o f analgesia by the d estru c­ tion o f l ew is p substances w hich are responsible for pain being f e lt.1 o nce the session is over, the patient's pain is dim inished and the structure hurts less when it is required to fu n ctio n .5 • d t f are applied a t 90 degrees to the injured fibres causing a transverse m ovem ent o f each fibre across the other. the action serves to b reak dow n the adhesive connections which bind the tissues together and resto re free m ove­ m e n t.1 • t issu e p erfusion is im ­ p ro v e d .1 • d t f stim ulates the m echa noreceptor cells. t h ere­ fore, im pulses from the m oving p arts take p rece­ dence o ver the afferen t sensory stim uli, thus re ­ lieving p a in .1 technique of dtf it is m ost im p o rtan t that the p erso n , p referab ly a p h y sio ­ therapist, w ho is giving d t f is fam iliar w ith the co rrect appli­ cation o f the technique. b efore com m encing, an accurate d ia g ­ nosis o f the injury based on the history, the site o f the lesion and the response o f the sym p­ tom s to specific testing p ro c e ­ d u res m ust b e m ade so that the therapist can d eterm ine w h eth er the injury w ill benefit from the technique. t h e struc­ tu re to be treated in this way m ust b e isolated and positioned in the co rre ct m anner. w h eth er the fin g er o r thum b pads o r the elbow are to b e used, the tw o skin surfaces m ust m ove in unison to p rev en t a friction injury to the skin i.e. a blister. t he fingers o r thum b should be in a sem i-rigid, flexed position and sw eep o v er the stru ctu re w ith the action controlled a t the w rist. p atien t co m fo rt and stru ctu re position m ust be m a in ta in e d th ro u g h o u t th e treatm ent. muscular injuries m uscles co n tract (concentri­ cally) by shortening and b ro ad ­ ening. an injury to a m uscle, b e it a strain o r tear, w ill ev en ­ tually resu lt in a fibrous scar form ing am ong the fibres. this reduces m o vem ent and causes pain w hen the m uscle con­ tracts. t h e effect o f d t f in the acu te stage is thus to m obilise the fibres in a tran sv erse d irec­ tion and p rev en t these ad h e­ sions from d eveloping. in the ch ro n ic m uscle tear, d t f act to b reak dow n these adhesions and im p ro v e the m u scle's co n ­ tracting m obility. p assiv e longitudinal stret­ ching plays an integral ro le in the m anagem ent o f m uscle injuries and is considered to be a vital tool in m aintaining or im proving fib re length and flexibility. h o w ev er, there is no clear p ro v en evidence to ind icate w h eth er stretching should be in co rp o rated a t the earliest stage o f treatm en t o r w h eth er it should only be in tro ­ duced in the latter stages w hen the injury show s signs o f heal­ ing. t h e ratio n ale o f an early in tro d u c tio n p ro p o se s that 20 --------------------------------sports m edicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy m uscle fib re length needs to b e im p ro v ed and capitalised on the increased m obility w hich d t f bring about, and that early stretching d irectly after d t f is thought to achieve this result. a som ew hat co ntras-ting opinion exists supporting the argum ent that stretching should begin at the end stage o f treatm ent. a lon­ gitudinal stretch on the m uscle lengthens th e fibres and in so doing causes them to com e into clo ser contact w ith each o th e r . t h is c o n tr ib u te s to w a r d s f u r th e r a d h e s iv e b inding o f the fibres and re ­ duces flexibility. t hus, early stretching w ould seem to d e ­ feat the aim s o f d t f , being to b reak dow n the adhesions and transversely m obilise the fibres. a s an altern ativ e to early stretching, activ e iso­ m etric contractions o f the m uscle in the shortened range are advocated to m aintain transverse m o b lity .2 tendon injuries l ogic w ould have it that any ov eru se friction injury should n o t b e treated by the sam e m ethod that caused it. in ten­ don lesions, this m ight seem the case, yet d t f is know n to achieve q u ick and satisfying results. in tenosynovitis, d t f p erfo rm ed in a too and fro m otion serve to sm ooth the surfaces o ff, and although lo n ­ gitudinal friction is the causa­ tive actio n , the cu rativ e fric­ tions are in the tran sv erse p la n e .2 in tendonitis, d t f act in m uch the sam e w ay as fo r m uscle injuries by breaking dow n the adhesions w ithin the tendon. ligament injuries t he action o f d t f in ligam ent injuries is to breaking up ad h e­ sions e ith er in the ligam ent it­ self o r binding it to the bone and so increase m obility. in the acute phase, only one to tw o m inutes o f m ild d t f is neces­ sa ry , w h e re a s in c h ro n ic sprains, up to fifteen m inutes o f treatm ent can be given. it is im p o rtan t w hen giving d t f to ligam ents that the affected ligam ent is positioned in a stretched position. f ailu re to bring ab o u t com plete healing can cause respraining fo r the lig am en t d u e to red u ce d strength and p ro p rio cep tiv e instability. contra-indications to dtf t he follow ing are conditions w here d t f are not indicated and should n ev er be attem pted: • b acterial inflam m ation; • calcific deposits in muscles o r tendons; • inflam m atory arthritides; • bursitis; • n erv e injuries; • t raum atic arthritis o f the elbow ; • t hrom bosis sim ulating a soft tissue injury. conclusion t h e topic o f d t f w ith respect to how and w hy it w orks is by no m eans an open and shut case. e vidence detailing its effectiveness and success as a m anipulative tech n iq u e (and th erefo re ju stify in g its usage in the treatm ent o f soft tissue injuries) has been explained and is o f co u rse open to discus­ sion. m o reo v er, the testim o­ nies am ong users and receivers o f the technique m ostly agree th at it do es w o rk , and v ery well at that. in o rd e r to satisfy the ev er questioning hum an m ind w ith feasible answ ers as to how and w hy it does w o rk , it is u nder­ standable that fu rth er ex­ p erim en tatio n , p erh ap s with p athological o r m agnetic reso­ nan ce im aging investigations, needs to b e p erfo rm ed in o rd er to b e able to d raw firm scien­ tific conclusions. h ow ever, science, w hich is its custom , has only m anaged to fuel the d eb ate on the efficacy o f d t f and is unable to at tim es p ro ­ v id e the m ost suitable answ ers. t h ere fo re , w e as ex p lo rers o f its d om ain should not let ou r m inds insistence fo r p ro o f cloud the reality that, although hum an reasoning m ight dent the efficacy o f d t f , its often astounding clinical results has its ow n w ay w ith g o d 's m ar­ vellous creation. m an can only stand by and w o n d er (in pain) ju s t how and w hy and for w hat reasons the facts about frictions add up. r e feren ces 1. k am enetzh l. history o f massage. in: manipulation, traction and m assage, ed. basmajian jv. wil­ liams and wilkins, baltimore, 1985. 2. cyriax jh. textbook o f orthopae­ dic medicine vol 2. bailliere tindall, london, 1980; 3-36. 3. noakestd. lore o f running. oxford university press, c apetow n, 1987. 4. corrigan b and maitland gd. prac­ tical orthopaedic medicine. butter worths, london, 1983; 26. □ sportsgeneeskunde vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ph y sio th er a py u pd a t e the comrades marathon as seen through the eyes of a physiotherapist joyce morton f o r the p hysiotherapist, c o m ­ rades m arathon starts many w eeks b efo re the event as v et­ eran runners and novices p o u r into o u r practices with m inor injuries, usually created by incorrect training m ethods. o ne o f o u r m ajor roles during this tim e is to en courage ru n ­ ners to ease back on th eir tra in ­ ing. n ovices especially, seem to think that if they do not run right up to the day b efore the race, they will not be able to run from p ieterm aritzb u rg to d urban. psychological su p ­ p o rt and counselling about glycogen sto rag e and fluid in ­ take are o f utm ost im portance at this stage. n ine years ago, the natal sports interest g roup o f the south a frican society o f p hy­ siotherapy volunteered the services o f physiotherapists along the route. smith and n ephew supplied the strapping and a nti-chafe and the service began. in those early years there w as much opposition from o u r medical colleagues involved with the organisation o f the race, for it was felt that if a ru n n er w as not well enough prepared then he should not run. also a runner should never stop as he w ould not start ru n ­ ning again. the survival shuffle was the slow est speed he should do. t h e organizing co m m ittee has now accepted that w e p erform a m ajor ser­ v ice on the day o f the race because there will alw ays be ru n n ers undertrained o r o v er­ trained w ho benefit from the service w e offer. t he c om rades c om m ittee consists o f judy m ck eon, kay m orely and m yself. o ur v o l­ unteers com e from the 3rd and 4th y ear physiotherapy students o f the u niv ersity o f d urban-w estville and natal p hysiotherapists. t h ere are 7 "e lastoplast" stations along the route and each station has sm ith and n ephew staff, a trained nursing sister, reco rd ­ e rs a n d p h y s io th e r a p is ts . sixty physiotherapy volunteers helped this year. c om rades m arathon day starts in the early hours o f the m orning for som e o f the p h y ­ siotherapists in p rivate practice w ho assist their patients by strapping them before they leave for the race. f o r the rest, the day starts from 5 o 'c lo c k o n ­ w ards depending on how far the station is from hom e. m> rule is to be dressed and ready by 6 o 'c lo c k , to w atch the stan o f the race on tv and then tc head for inchanga 48 km s frorr d urban. even at this hour, w ithout a "r efreshm ent" sigr stuck to my w indscreen, i 22 _______________________ sports m edicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) pi iy si oti ie rap y update w ould not be allow ed onto the old m ain road as the police are already on duty. o ur w orking area has been cornered o f f by p eter h am ­ m ond, the sm ith and n ephew man. all we have to do is put up banners to alert the runners to the fact that there are phy­ siotherapists ahead o f them . t ables are set up w ith hundreds o f rolls o f elastoplast, a nti­ chafe, cottonw ool, elastozoff, b lister plasters and this year, tubes o f v oltaren donated by c iba-g eigy. lastly o ur long rail is set up near the road. this rail is about a m eter high. it rem inds me o f the cow boys w ho used to tie their horses on sim ilar rails outside the old w est bars. t he runners lean on the rail in o rd er that their legs, backs o r necks m ight be treated w ithout their having to lie dow n. t w o large mats are placed on the ground for runners with blisters, head­ aches, painful feet or ankles as w e cannot treat these ailm ents unless the patient sits o r lies dow n. w e ju s t have tim e to eat a delicious break fast cooked and donated by p eter, when the first runners appear. t o them the inchanga h ill is no threat and w e clap to co ngratulate them as they run past. h o w ­ ev er, it is not long afterw ards that the first o f the runners stops to ask for help at ou r sta­ tion. w e offer three main ser­ vices; to rub aching m uscles using a nti-chafe; to rub using ice o r to strap using elasto­ plast. t h e ice is by far the most p o p u lar treatm ent. h undreds o f p o lystyrene cups are filled w ith w ater and frozen. this m eans that the physiotherapist does not get a frozen hand as she rubs the ice onto a runner. i am sure that any physiother­ apist reading this will tell me that tw o m inutes o f rubbing w ith ice can have no real effect on a runner. o ur investigations done o v er the years have shown that ice does help and m ore and m ore runners are asking to be treated with it. at the inchanga station judy and i alw ays take on the task o f strapping. t ogether this year, o ver a period o f approxim ately one and a h alf hours, w e strapped 160 parts o f t h is y e a r ....... 13 9 8 8 r u n n e r s s ta rte d th e r a c e , 12 081 fin is h e d th e r a c e , 1 0 2 8 ru n n e r s w e r e a d m itte d to te n ts f o r m e d ic a l tr e a tm e n t sportsgeneeskunde vol. 6 no. 3 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ph y sio th er a py update the body. m ost o f the p ro b ­ lems are knees caused w e are sure, by o v er training o r in co r­ rect shoes. in o rd er to reach the knees, one has to kneel. no one has ev er done research on the frequency o f patella ten­ d o n itis in p h y sio th e ra p ists kneeling on the road during an ultra marathon! b ecause this y ear was a down run, as expected, many o f the runners com plained o f an ilio-tibial band friction syn­ d ro m e. o ur advice to these runners w as to w alk dow n the hills backw ards. m ost friction o f the band is at 30 degrees o f flexion and this does not happen when one w alks b ack ­ w ards. it m ust be rem em bered that many o f these runners are trying to beat the 11 hour gun, and they definitely have the tim e to w alk dow n hills. t h e runners stopping at our station increase to an alm ost unm anageable num ber. p hy­ siotherapists are seen to be s tr e tc h in g c ra m p e d h a m ­ strings, m obilizing painful backs, giving advice, kneeling on the road to rub a calf, bend­ ing o v er to reach a painful knee, helping a runner remove a shoe, kneeling on the mat to m obilize a cervical spine, running next to a ru n n er to give him some anti-chafe, rem oving rubbing cream s with e l a s to z o f f so that e lastoplast m ight stick and g enerally m anaging to achieve the im possible. then suddenly, as fast as they ap ­ pear, they all disappear except for one o r tw o runners who have throw n in the towel and are w aiting for the c om rades bus to take them to d urban. i b attle to rise from the road obviously age has som ething to do with it and take a sip o f coke which tastes like nectar. w e w earily tidy up, pack our cars and head for hom e know ­ ing that as we do, so there are thousands o f runners grateful to the physiotherapists who have in som e small way helped them to achieve their goal o f com pleting a c om rades m arathon. o ne feels my story should end here, but it does not. som e o f us d rive down to k ings p ark and w ork in the red c ross tend until 8 pm . o ur main function is to help b reak the excruciating cram ps w hich the overo r under-hydrated ru n ­ ners get when they stop ru n ­ ning. t o w ork in the red c ross o r the m edical t ent is an ex ­ perience no m edical person involved in the treating o f marathon runners should miss. it alw ays rem inds me o f a battle station. t he w ork done by the hundreds o f volunteers is h eart­ w arm ing and ju s t reinforces w hat kindness man can do to man ... but th a t's an o th er story to be w ritten som e o th er tim e. t his year, the official fig­ ures are that 13 988 runners started the race, 12 081 fin ­ ished the race, 1 028 runners w ere adm itted to the m edical, red c ross o r st johns tents for medical treatm ent. o ur as yet unconfirm ed figures show that the phy sio ­ therapists in the seven smith and n ephew stations treated approxim ately 4 000 ailm ents. t h e c om rades h ouse has been inundated with telephone calls from runners all o v er the co u n ­ try, asking that the physio­ therapists be thanked for the w ork they do on c om rades d ay. it really m akes it all w orth w hile. □ (s3] v /3 .1 /6 2 , v /3.1 /2 38 w .f .i. h /34/128 tilc0til® c o m p o n e n ts : t e n 0 x ic a m 2 0 m g indications: s y m p to m a tic tre a tm e n t o f the fo llo w in g p a in fu l in fla m m a to ry and d e g en erative d is o rd e rs o f the m u s c u lo s k e le ta l s ys te m : rh e u m a to id a rth ritis ; o s te o a rth ritis ; a n k y lo s in g s p o n d y litis ; e xtra a rtic u la r d is o rd e rs , e .g . te n d in itis , b u rs itis , p e ria rth ritis , g o u ty a rth ritis (fo r ta b le ts ). dosage: 20 m g once d a ily at the sam e tim e each day. the p arenteral fo rm is used fo r one o r tw o d ays. for tre a tm e n t in itia tio n in a cu te g o u ty a rth ritis 40 m g (2 ta b le ts ) once daily fo r tw o days fo llo w e d by 20 mg once d a ily fo r a fu r th e r five days is re c o m m e n d e d . c o n tra-in d icatio n s: k no w n h y p e rs e n s itiv ity to the d ru g . p atie nts in w h o m s a lic y la te s o r o th e r n o n s te ro id a l a n ti­ in fla m m a to ry d ru g s (n s a id s) in d u ce s y m p to m s o f a s th m a , rh in itis o r u rtic a ria . p atie nts w ho are s u ffe rin g o r have s u ffe re d fro m severe diseases o f the u p p e r g a s tro in te s tin a l tra c t, in c lu d in g g a s tritis , g a s tric and duo de na l u lc e r. b efore anaesthesia o r s u rg e ry , 't il c 0 t il ' s h o u ld n o t be g ive n to p a tie n ts at ris k o f kidn ey fa ilu re , o r to p a tie n ts w ith increa se d ris k o f b le e d in g . c o n c u rre n t tre a tm e n t w ith sa lic y la te s o r o th e r n s a id s s h o u ld be a vo id e d . p re g n a n c y and la c ta tio n . p recautions: s im u lta n e o u s tre a tm e n t w ith a n tic o a g u la n ts a n d /o r oral a n tid ia b e tic s s h o u ld be a voided u n le ss the p a tie n t can be c lo s e ly m o n ito re d . renal fu n c tio n (b u n , c re a tin in e , d e v e lo p m e n t of o ed em a , w e ig h t g ain , e tc .) s h o u ld be m o n ito re d , w h e n g iv in g a nsaid to the e ld e rly o r to p a tie n ts w ith c o n d itio n s th a t c o u ld in c re a se th e ir ris k of d e v e lo p in g renal fa ilu re . packs: t a ble ts 20 m g : 1 0 ’ s, 3 0 's . vial pack c o n ta in in g 1 vial active s u b s ta n c e and 1 a m p o u le w a te r fo r in je c tio n . 24 ----------------------------------sports m edicine vol. 6 no. 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) volume 5 • number 2 □ october 1998 the south african journal of sports medicine the official publication of the south african sport medicine association r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) very one f e e l s pain at some time . . . fobemoo • s i g n i f i c a n t a n a l g e s i c , a n t i i n f l a m m a t o r y and a n t i p y r e t i c action. • r a p i d t h e r a p e u t i c r e s p o n s e e n s u r e d 1. • a c t i o n p a c k c o n t a i n i n g 15 tab lets. • p a c k o f 12 s u p p o s i t o r i e s . he flurbiprofen 100 mg. knolltablets 100 mg. suppositories 100 mg. basf p h a r m a r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial the content of the second issue of the journal in 1998 is representat ive of the diversity of scientific interests among members of the south african sports medicine association (sasma). i believe that the strength of the association lies in this diversity, and 1 remain convinced that sports medicine is best practiced and researched in a multi-disci­ plinary setting. i'll is issue has a mmiber of unique contributions. firstly, dr myburgh contributed the invited review art icle for this edition. the importance of achieving an optimum peak bone mass must be emphasized. in particular, the positive role of physical activity to achieve peak bone mass must be eucoiu-aged in children and adolescents. as pointed out by dr myburgh, it is important to remember that the voimg female athlete with menstrual dysfunction can develop a low bone density, and clinicians must be aware of this potential danger. the editorial board of this journal will con­ tinue to publish high quality invited review articles of similar caliber to the one written by dr myburgh. secondly, the original research articles in this edition are once again of a high standard, and represent different areas of sport mcdienc. dr du toil and his colleagues designed a unique study to examine the force absorption and rebound characteristics of cricket batting pads. their results are likely to influence the design and choice of pads used by play­ ers. ms fuller and her colleague investigated the potential use of an infrared auditory canal thermometer to measure the core temperature in athletes a clinical measurement that is of extreme importance in diagnosing heat illness. they conclude that infrared auditory canal thermometry is too variable and does not provide the clinician with a “ quick and easy” measure of core tempcratiu e. thirdly, we are happy to introduce a new form of presenting research data in die form of a brief report. this format allows researchers to publish data that is of interest, but where the content, depth or limitations preclude it from being published as a full research article. dr marino reports on the urinary catecholamine excretion during outdoor sports rock climbing. he concludes that urinary catecholamine excretion does not increase after a strenuous climb of 7-8 minutes. finally, we are proud to publish the position statement 011 “ ethics in sports medicinc” , which has been reproduced, with permission, from the international sports medicinc federation (fims). we will, in future, continue to publish position statements, as these are a very useful yardstick by which we can evaluate our approach to problems (clini­ cal and other) in sports medicine. 1 would like to lake this opportunity to thank the international sports medicine federation (fims) for allowing us to publish their material. now it just remains for me to wish you all a happy festive season, a restful holiday, and great sporting and personal success in 1999. prof mp schwellnus, mbbch, msc (med), md, facsm editor south african journal of sports medicine sports medicine october 1998 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the south african journal of sports medicine volume 5 number 2 october 1998 editor in chief prof mp schwellnus university of cape town senior associate editors prof m mars university of natal dr m lambert university of cape town news editor dr p mac farlane general practitioner, cape town editorial board profy coopoo university of durban westville dr k myburgh university of stellenbosch prof td noakes university of cape town prof g rogers university of the witwatersrand prof k vaughan university of cape town the editor the south african journal of sports medicine po box 115, newlands 7725 tel: (021) 686-7330 fax: (021) 686-7530 contents editorial 1 mp schwellnus review article: 3 exercise and peak bone mass: an update k h myburgh research article: 9 the force absorption and rebound characteristics of cricket batting pads at four impact velocities r stretch, e du toit, t edwards, b pretorius research article: 14 comparison of oral and infrared auditory canal thermometry in sports participants a fuller, d mitchell brief report: 19 urinary catecholamine excretion during outdoor sport rockclimbing f marino, j booth position statement: 22 code of ethics in sports medicine international sports medicine federation (fims) sasma news 24 production advertising andrew thomas andrew thomas reproduction output reproduction publisher glenbarr publishers cc printing tel: (o il) 442-9759 ince the views expressed in individual articles are the personal views of the authors and are not necessarily shared by the editors, the advertisers or die publishers. no articles may be reproduced without the written consent of die publishers. 2 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) review a r t ic l e exercise and peak bone mass: an update kh myburgh (phd) department o f human and animal physiology, university o f stellenbosch, south africa introduction exercise has been widely recommended as a means of preventing osteoporosis. the rationale for this recom­ mendation was based largely on the inference that immobilisation and weightlessness lead to bone loss and therefore exercise should lead to bone gain. since peak bone mass is a major determinant of bone mass and fracture risk later in life, any factors that could enhance peak bone mass can be considered to be ben­ eficial in preventing osteoporosis in the long-term. exercise is a lifestyle factor that can be modified and if it does indeed increase peak bone mass, it may offer protection against bone fragility in old age. new evi­ dence suggests that exercise (luring growth can lead to large increases in bone mass.2,1” if these increases are maintained into early adulthood, they wall result in increased peak bone mass. in contrast, during adult­ hood exercise results in relatively small gains in bone mass and appears to play a more important role in maintenance of bone density and possibly prevention of early bone loss. exercise may not always be beneficial however, since athletic primary and secondary' amen­ orrhea may lead to either a failure to gain bone or bone loss. current nomenclature: in vitro measurement of bone breaking strength has determined that bone den­ sity can account for up to 80 percent of the variance/" therefore bone density is used as a surrogate measure of the breaking strength of bone. in vivo measurement of the mineral content of the skeleton can be done using dual energy x-ray absorptiometry (dxa) or quantitative computed tomography (qct). both deter­ mine an estimate o f bone mineral content, which can be expressed as either a mass or a density. bone mass is the amount of mineral in grams (g) unadjusted for size. bone mass divided by the area of the region analysed (g /cn r) is termed areal bone density. although areal bone density only adjusts for the width and length of a bone (not depth), it is the unit most commonly reported in the literature. volumetric bone density is the bone mass divided by the volume of the correspondence: dr kh myburgh dept human & animal physiology, university of stellenbosch, private bag x i matieland 7602 tel: 27 21 808 3149 fax: 2 7 2 1 808 3145 e-mail: khm@maties.stm.ac.za region measured (g/cnr1) and can be calculated from dxa scans by using equations that estimate the size of the vertebra and femoral neck.5 this estimate is termed bone mineral apparent density (bmad). the term ‘density’ without a clarifying prefix can be misleading because it does not distinguish between areal, volumetric or apparent bone density. analysis of samples of bone has shown that true bone density does not increase with age or size. in other words, the chemical composition of the skeleton remains con­ stant during growth and adulthood.49 “ it is important to acknowledge that an increase or decrease in areal or volumetric bone density is not a change in the chemi­ cal composition o f bone but rather a change in total bone length, bone size, cortical thickness, medullary width and/or the biomechanical organisation of the trabecular structure.40 when is peak bone mass achieved? peak bone mass is the term used to describe the max­ imal lifetime amount o f bone tissue aquired in individ­ ual bones and the whole skeleton. it is the conse­ quence o f the nett accrual of bone mass due to growth during the childhood years and the balance between accrual and resorption rates in the adult pre­ menopausal period. approximately 80 to 85 percent of peak bone mass has been accrued by the age of menar che. about half of this is achieved during pre-pubertal growth (~10 to 12 years) and the other half is achieved very rapidly in the 2 to 4 years of pubertal growth.14 bone mass accrual continues slowly after puberty and contributes a further 15 to 20 percent to the peak bone mass. while it is well accepted that bone mass con­ tinues to be accrued after linear growt h has ceased (at about 16 years in females) there is still debate about when peak bone mass is achieved. there have been reports that peak bone mass may be achieved from as early as 17 to 18 years to as late as 35 years.17 *’-54 theintz et al. (1992) showed no increase in bone density at the femoral neck or the lumbar spine after 17 to 19 years of age.54 in contrast mazess and barden (1991) report that peak bone mass may be achieved later in adulthood. they reported small differences in bone density between women aged 20-24 and women aged 30-34: lumbar spine was 3% higher in the older cohort, but no differences were noted in the femur.33 there are several reasons for these conflicting results: a) measurement of bone mass at one site may not be representative of the entire skeleton or other sites within the skeleton; b) expression o f results as bone mass may differ from expression of results as bone density due to changes in bone shape and c) the results of cross-sectional studies can be influenced by sports medicine october 1998 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:khm@maties.stm.ac.za the different cohorts.*’ the results of prospective studies support the notion that peak bone mass may be achieved later rather than earlier in adulthood. bennell et al. (1997) studied subjects aged 17 to 26 years for one year.3 this study showed increases in t he range of 2.2% in total body bone mass in the female subjects. in a longer study 156 women were followed for up to 5 years and peak bone mass was reported to be achieved between 28 and 30 years of age.4'1 there is also debate about how long peak bone mass is maintained before bone loss begins. there may be a plateau in bone mass or bone loss may occur short­ ly after peak bone density has been achieved. two studies support the concept of early bone loss: 1) matkovic et a], (1994) reported that the bone density o f the proximal femur was about 15 percent lower in older premenopausal women compared to younger pre­ menopausal women,32 and 2) bonjour et al. (1991) reported that the spines of adolescents (aged 14 to 19 years; n =24) had 10% higher trabecular bone density than young adults (25 to 35 years; n = 24).4 not all studies report a statistically significant decline in bone density with age during the pre-menopausal period.133'’ the maintenance of bone mass in the lumbar spine and femoral neck has been reported in longitudinal studies of women in their thirties.33 35 individual variation may explain these conflicting results. this individual vari­ ation in the rate of change and direction of change in bone mass was highlighted by mazess and barden (1991) who reported that there was no detectable rela­ tionship between age and bone mass in a large group of subjects aged 20-39 years. however, 63 subjects decreased spine bone density by7 more than 2%, where­ as 100 subjects showed change of less than 2% in either the positive or negative direction and a further 68 subjects gained more than 2%.33 in summary, there is clear evidence that the major­ ity of bone mass is accrued during preand peri-puber tal years and that bone mass continues to be accrued at a slower rate in the post-pubertal years. there is still controversy7 about when peak bone mass is achieved and how long it is maintained, but the timing o f the attainment of peak bone mass and bone loss is most likely7 a) site-specific and b) variable between individuals. this heterogeneity between individuals in ay be the result of the interaction between genetic and environmental determinants that influence bone mass. the genetic determinants o f peak bone mass the variance in peak lumbar spine bone density varies between -20% and +20% of the mean. family studies have shown that 60 to 90% of this variation between individuals is genetically7 determined/10 it has also been found that the genetic effect is greater at the lum­ bar spine (up to 90%) than the femoral neck (up to 70%).s1 a finding that is clinically7 important is that pre­ menopausal women with a maternal family history7 of osteoporosis have low bone density,1 and peri menopausal women with a family history7 of hip frac­ ture also have low bone density.™ interestingly, daugh­ ters of mothers with hip fractures had low bone densi­ ty at the hip, while daughters of mothers with spine fractures had low bone density at the spine50 51 indicat­ ing that this familial association may also be site spe­ cific. while a large proportion of the variance in bone density may be genetically7 determined, environmental factors also account for a clinically important propor­ tion of the variance.4" these influences may not be independent as it has been suggested that there is a common genetic control of both muscle mass and bone mass, both of which can also be affected by exercise. "1 the osteotrophic effect o f exercise on bone density in adult premenopausal women early7 studies of exercising subjects seemed to indicate that exercise could substantially improve bone mass. for example, the dominant arm in tennis players has higher bone mass than their non-dominant arm.-1 the reported differences between the two arms in compet­ itive club players were between 8% and 13%, and even larger differences were reported in the professional playrers. however, cross-sectional data of mature ath­ letes does not give an indication of whether the adap­ tation occurred in childhood or adulthood. therefore, to investigate the effects of exercise on adult bone mass, a longitudinal approach is preferable. the effect o f aerobic exercise on bone density in the adult has been reviewed, and the following consensus has been reached: early cross-sectional studies were confounded by sampling bias and led to the belief that exercise in the adult could lead to large increases in bone density (up to 20%). intervention studies tended to show mixed resul ts ranging from small increases (2 to 3%), to no change or even bone loss.15 weight training was hypothesised to have a greater osteotrophic effect than jogging or walking since weight training places a greater load on the skeleton to which it must adapt. intervention studies in pre­ menopausal women ranging from 4 to 24 months have shown inconsistent findings.16 1h 29 47 53 some o f these studies reported small but statistically significant changes of 1 to 2 percent; others showed no change in bone mass or bone loss. friedlander et al. (1995) reported that the change in lumbar spine bone density alter 2 years of aerobics and weight training in adult women (aged 28 years),10 was similar to that found by snow-harter et al. (1992) after 8 months (1.3% for both studies),83 indicating the possibility of a plateau hi the adaptation to exercise. in the study the femoral neck bone density increased even less (0.5 ± 0.5%) with weight training but this was in contrast to a group of women who only7 did stretching exercises and who lost 1.9 ± 1.0% (p<0.05). although weight training places a high load on the skeleton, it is possible that the impact is not high since there is no momentum at the initial contact. the osteotrophic effect on the skeleton of high and low impact loading has also been investigated, albeit in postmenopausal women. kenet al. (1996) randomised 56 subjects to a high or low impact exercise group.27 4 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) both groups exercised three times per week for 12 months. increases were found in the high impact group at the trochanter, wards triangle and ultra dis­ tal radius o f between 1.7 ± 4.1% and 2.4 ± 4.3%). there was no increase at the femoral neck or other radial sites. there were no changes at any site (relative to baseline) in the low impact high repetition group and a control group lost bone density at most sites (changes between 0.8 ± 5.2 % and -1.4 ± 2.3 %). sports where impact loading is high, may also lead to increased bone density. higher bone density has been reported in athletes who play volleyball and bas­ ketball,45 and in college gymnasts.1'’ the extent of the differences can be substantial (see table 1). it should be remembered that firstly the results could be affect­ ed by selection bias, and secondly it can not be deter­ mined from these studies what proportion of these benefits were gained from exercise during childhood and adolescence, and what proportion was gained from exercise in adulthood. the clinical relevance of exercise in the prevention o f osteoporosis lies in the reduction of fracture risk late in life. it is generally accepted that a 10% increase in bone density' is associated with halving the risk of femoral neck fracture." moderate exercise of any type in adulthood is unlikely to result in such large increas­ es in bone mass. but a long term commitment to an active lifestyle, including exercise that places a mechanical load on the skeleton, through the pre-, peri-, and postmenopausal years may help reduce frac­ ture risk by reducing bone loss and ind irectlv by reduc­ ing the risk of falling by improving muscular strength, coordination and balance. the effect o f menstrual irregularity on hone density research in the mid-eighties and subsequent research has confirmed the long term risk of osteopoenia asso­ ciated with athletic amenorrhea. " :,1m the decrements in bone density are seen relative to both sedentary' peers, and eumenorrheic athletic controls. the skele­ tal site most affected by menstrual dysfunction is the lumbar spine, a site containing a large proportion of trabecular bone."131 the deficit in bone density relative to eumenorrheic athletes has been reported to be as high as twenty percent.31 up to fotu percent of trabecu­ lar bone can be lost in the first year of secondary' amen­ orrhea and bone loss continues for at least two years.38 more recent studies have reported that oligomenor­ rhea is also associated with low' bone density,28 34 despite no episodes of amenorrhea.34 there appears to be a relationship between bone density and the sever­ ity of current and previous menstrual history expressed either by category','1 or the number of cycles per year since age thirteen years.114 it has also been sug­ gested that more subtle hormonal disturbances may' affect bone mass, even w'hen menses is regular. women with more than one short luteal phase per y'ear or anovulatory cycles, may lose bone mass due to decreased progesterone secretion.4' but de souza et al. (1997) follow'ed exercising w'omen for three months and reported that luteal phase insufficiency w'as asso­ ciated with decreased progesterone, but not decreased bone density, wliereas reduced estrogen production in the follicular phase, despite regular menses, w'as asso­ ciated with low'er bone density.8 can exercise offset hone loss associated with menstrual dysfunction ? despite low'er bone density at lite spine, amenorrheic athletes have either high or normal bone density at w'eight bearing sites. one explanation for this trend is that exercise may' offset the negative effects of amen­ orrhea at the w'eight bearing sites. tw'o factors argue against this explanation: 1) bone density o f the w'eight bearing sites may be higher than the non-w'eight bear­ ing sites because of previous loading before exposure to estrogen deficiency' and 2) trabecular sites are more at risk of early' bone loss and cortical sites later bone loss, so that only' trabecular bone loss is evident at the stud}' time. pearce et al. (1997) have reported low'er bone density at the w'eight bearing sites only' in ballet dancers with longer time periods of oligomenorrhea.41 exercise with higher impact loading than ballet may offer protection at the w'eight bearing sites. in a group of figure skaters with a substantial history' of menstrual irregularity bone density w'as enhanced in the low'er limbs, but not in the lumbar spine.52 robinson et al. (1995) reported that gymnasts had higher bone density at all sites compared with runners w'ho had a similar incidence of menstrual dy'sfunctable 1: lumbar spine and lower limb bone density in gy mnasts, volley ball and basketball play ers compared to non-athletes. group ls bmd diff vs control fn bmd diff vs control reference g/cnr % g/cm 2 % controls 0.11 ± 0.11 0.97 ± 0.10 no 46 gymnasts 0.17 ± 0.13 + 5.4 % 1.09 ± 0.12 + 12.4 % no 46 calcaneus bmd controls 1.15 ± 0.03 0.424 ± 0.019 no 45 volley'ball 1.32 ± 0.04 + 14.8 % 0.536 ± 0.017 + 26.4 % no 45 basketball 1.29 ± 0.03 + 12.1 % 0.575 ± 0.022 + 35.6 % no 45 abbreviations: ls bm d = lumbar spine bone mineral density; f n b m d = femoral neck hone mineral densityj; d iff = difference sports medicine october 1998 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) tion.4<i it is possible however that the gymnasts’ higher bone density was not due to a protective effect of exer­ cise during the time period of menstrual irregularity, but rather may have been the result of exercise loading prior to the exposure of estrogen deficiency. only lon­ gitudinal studies can clarity these issues. resumption on menses and its effect on bone density in previously amenorrheic athletes gains in lumbar spine bone density (6-7% per year) have been shown in the year or two immediately fol­ lowing resumption of menses in previously amenorrhe­ ic athletes.11 these gains however, did not appear to be sufficient to completely reverse the original deficits in bone density compared with controls (see table 2) and one study has shown no further increase in the third year after resumption of menses.38 other more long term studies in subjects with a prior h istory of men­ strual irregularity who had been menstruating regular­ ly for up to 10 years at follow-up still showed a 14-15% deficit in lumbar spine bone density.26 35 these data suggest that there is irreversible bone loss in athletes with former menstrual irregularity . one possible treatment for athletic amenorrhea is hormone replacement therapy (hrt) in the form of oral contraceptives. the effectiveness o f hormonal therapies in the treatment of athletic amenorrhea is unknown. to date there has been only one retrospec­ tive clinical study and one randomized clinical trial investigating the effect o f estrogen replacement thera­ py and oral contraceptive use on bone density in young women with hypothalamic amenorrhea. cummings et al. (1996) reported that estrogen replacement therapy for 24 to 30 months increased vertebral and femoral neck bone density by 8 ± 1.2% and 4.1 ± 0.3% respec­ tively in 8 amenorrheic runners.7 in contrast, 5 amen­ orrheic runners who did not agree to take hrt experi­ enced non-significant decreases of less than 2.5% in bone density at both sites. hergenroeder et al. (1997) investigated the effect of 12-months of oral contracep­ tives, medroxy-progesterone or placebo on bone densi­ ty in 15 amenorrheic women aged 14 to 28 years.20 four of the subjects had a current diagnosis of anorex­ ia or bulimia nervosa, and one subject in each group did not exercise. twelve months of oral contraceptive use led to a significant increase in bone density at the lumbar spine but not the femoral neck (5.4% and 3.7% respectively). after 12 months changes inbone density were not statistically significant for the medroxy-prog­ esterone and placebo groups (lumbar spine: -10.2% and -0.7% respectively and femoral neck: +4.2% and -3.4% respectively). the results o f these studies suggest that either hrt or oral contraceptive use may be effective in increasing lumbar spine bone density and femoral neck bone density, although the latter may only be sig­ nificant after at least two years. further studies are needed to confirm these results as the sample sizes were small and in the study by hergenroeder et al. (1997) the subject sample was not homogenous (ath­ letes and patients with eating disorders). it is recom­ mended that athletes with amenorrhea be monitored for bone loss and early intervention be considered.720 the osteotrophic effect o f exercise during growth during childhood and adolescence there are large gains in bone mass that may be magnified by exercise. the first studies to show that large increases in bone density may be achieved during growth were unilater­ al loading studies. the strength of these studies is that the noil-dominant limb controls for genetic deter­ minants of bone density. the radius and humerus of adult tennis and squash players had 9% to 35% greater cortical thickness and bone mass in their playing arm compared to the non-playing arm.21 24 kannus et al even reported that the bilateral differences in bone mass were two to four times higher in those players who had started training before or at menarche (10 to 23%), compared to those who started more than 15 years after menarche (2% to 9%). similarly, femoral neck, trochanter and distal radius bone density was greater (8-30%) in young elite gymnasts (aged 7 to 11 years). ' 1'' the greatest differences were found in the arms, a weight bearing site in gymnastics. selection bias is unlikely to explain a large proportion of the higher bone density in the gymnasts since dyson et al.13 reported that there were no significant differences in bone density between the mothers of the gymnasts and the mothers of the controls. does intense training in childhood confer benefits in bone density in adulthood? retired gymnasts have also been shown to have site specific higher bone density supporting the hypothesis that these childhood gains in bone mass can be main­ tained into adulthood.2 despite reduced physical activ­ ity in retirement, bone density was 1 to 1.5 standard deviations higher in the retired gymnasts at the weight bearing sites, but normal at the non-weight bearing sites compared to age-matched controls. this trend for retired athletes to have site specific surfeits in bone density related to the unique loading patterns table 2: effect o f resmnption o f menses on imnbar spine bone mineral density (g/cm a) baseline baseline difference follow-up* follow-up* difference reference control mi vs control control mi vs control 1.300 1.120 14 % 1.369 1.198 12.5 % no 9, 10 1.250 1.050 16% 1.290 1.190 -8 % no 23 1.088 0.946 13 % 1.043 0.936 10 % no 34, 35 * not all subjects were available for follow-up. abbreviations: m i = menstrual irregularity 6 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) associated with training in childhood and adolescence has also been reported in tennis players,'1 soccer play­ ers,12 and weight lifters."" moderate physical activity and bone density in active non-athletic children improvements in bone density in competitive athletes may not be reflected to the same extent in active non athletic children. gunnes and lehman (1996) report­ ed that weight bearing exercise accounted for 5% to 16% o f the variance in the change in bone density with age in children and adolescents depending on the site, age and gender.10 nevertheless, several long term longitudinal stud­ ies have shown that exercise was a predictor for adult bone density.057 cooper et al. (1995) also investigated the relationship between bone density in adulthood and exercise. women in the highest activity category had 12% higher bone density at the femoral neck than women in the lowest activity category.6 femoral neck bone density in the women in the moderate activity category was 7% higher than the least active group. these results however may be biased, as children who have a larger musculoskeletal mass may be more likely to participate in physical activity. intervention studies are currently behig conducted, but few have been published. morris et al. (1997) conducted a ten month exercise program structured into the school curriculum lor pre-pubertal girls (aged 9 to 10 years). the bone densit y increased more in the exercise group compared with controls at the legs, arms, lumbar spine, and femoral neck.36 conclusion for exercise to have a role in the prevention of osteo­ porosis the osteotrophic response must be large enough to be considered clinically important. also, the gains due to exercise must be maintained into adult­ hood and later in life. large increases in bone density have been reported in children and adolescents involved in competitive exercise programmes with extensive training, but it is unknown how' long these are maintained. the evidence that some retired ath­ letes have site-specific higher bone density related to the unique loading patterns of their sport suggests that at least some of the benefits are not lost. in contrast, moderate weight bearing exercise in non-athletic chil­ dren is associated with somewhat: less benefit to bone density in adulthood. exercise intervention in adult­ hood is even less positive for enhancing bone mass unless tlie impact is high, but the importance of exer­ cise in adulthood is concerned mainly with conserva­ tion of bone.:,!l it can be said that the adult skeleton is much more responsive to the adverse effects of unload­ ing than to the beneficial effects of overloading.39 exercise may not always be beneficial however, espe­ cially if it is associated with the development of amen­ orrhea or oligomenorrhea which may lead to large deficits in bone density (up to 20%) due to either a fail­ ure to gain bone or bone loss. recent evidence has also shown that even long term resumption of regular menses has failed to restore these deficits. tlie utili­ ty of exercise to offer protection or restore bone mass in amenorrheic athletes appears to be limited, alter­ native measures for bone gam must be investigated and promoted, hi summary, exercise has an important role in increasing peak bone mass and bone strength during tlie growing years and maintaining bone mass in tlie premenopausal years. these findings support tlie promotion of w'eight bearing exercise in girls, teenagers and young women and highlight tlie impor­ tance of regular menstrual fimction. references 1. armamento-villareal r, villareal dt, aviolo l v & civitelli r. estrogen status and heredity are major determinants o f premenopausal hone mass. j clin invest 1 9 9 2 ; 90, 2464 71. 2. bass s, pearce g, bradney m, hendrick e, delmas p, harding a & sceman e. exercise before puberty may con­ fer residual benefits in hone density in adulthood: studies in active prepubertal ancl retired female gymnasts. j bone miner r es 1998; 1 3 ( 2 ) , 500-7. 3. bennel k l, malcolm .s71, khan km , thomas 5/1, reid sj, brukner pd, eheling pr & wark jd. bone mass and bone turnover in power athletes, endurance athletes, and con­ trols: a 12-month longitudinal study. bone 1997: 20, 477 84. 4. bonjour jp, theintz g. buchs b, slosman d & rizzoli r. critical years and stages o f puberty for spinal and femoral hone m ass accumulation during adolescence. j clin endocrinol metah 1 9 91 ; 73, 555-63. 5. carter d r, bouxsein m l & marcus r. new approaches for interpreting projected hone densitometri) data. j bone miner r es 1992; 7, 137-45. 6. cooper c, cawley m, bhalla a , egger p, ring f, morton l & barker d . childhood growth, physical activity, and peak bone mass in women. j bone miner r es 1 9 9 5 ; 1 0 ( 6 ) . 9 w 7. 7. cummings dc. exercise -associated amenorrhea, low hone density, and estrogen replacement therapy. arch intern med 1996; 156, 2193-5. 8. de souza mj, miller be, sequenzia lc, luciano a a , ulreich s, stier s, prestwood k & lasley bl. bone health is not affected by luteal phase abnormalities and decreased ovarian progesterone production in female runners. j clin endocrinol metah 1 9 97 ; 82, 2 8 67 -2 876 . 9. drinkwater bl, bruemner b & chestnut ii i ch. menstrual history as a determinant o f current hone density in young athletes. j a m a 1990; 2 6 3 ( 4 ) . 545-8. 10. drinkwater b, nilson k , chestnut c, bremner ivj shainholtz s. & southworth m. bone mineral content o f amenorrheic and eumenorrheic athletes. n engl j med 1984; 311, 277-81. 11. drinkwater b, nilson k, o tt s & chestnut i i i ch. bone mineral density after resumption o f menses in amenorrheic athletes. j a m a 1986; 25 6, 380-2. 12. duppe ii, gardsell p, johnell o & ornstein e. bone miner­ al content in female junior, senior and former football play­ ers. osteoporosis int 1 9 96 ; 6, 437-41. 13. d yson k , blimkie cjr, davison s, webber ce & adachi jd. gymnastic training and bone density in pre-adolescent females. med sci sports exerc 19 97 ; 2 9 ( 4 ) , 443-50. 14. faulkner r a , bailey d a , drinkwater dt, wilkinson a a , houston cs & m ck ay h a . regional and total body bone mineral content, bone mineral density, and total body tis­ sue composition in children 8 -1 6 years o f age. calcif tissue int 1993; 53, 7-12. 15. forwood m & burr d . physical activity and bone mass: exercises in futility? bone miner 1 9 93 ; 21, 89-112. 16. friedlander a l , genant iik , sadowsky s, b y i nn & gluer c. a two-year program o f aerobics and weight training enhances bone mineral density o f young women. j bone miner res 1995; 1 0 ( 4 ) , 574-85. sports medicine october 1998 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 17. gilsanz v, gibbens dt, carlson m, boechat m l, cann ce & schulz e e . peak trabecular vertebral d en sity: comparison o f adolescent and adult females. calcif tissue int 1988; 43, 260-2. 18. gleeson pb, protas ej, leblanc a d , schneider vs & evans hj. effects o f weight lifting on bone mineral density in premenopausal women. j bone miner r es 1 9 90 : 5 ( 2 ) , 15s-8. 19. gunnes m & lehman e ll. physical activity and dietary constituents as predictors offorearm cortical and trabecu­ lar bone gain in healthy children and adolescents: a prospective study. a c ta paediatr 1 9 9 6 ; 85. 19-25. 20. hergenroeder a c , o'brian smith e, shypailo r, jones l a , klish wj & ellis k. bon e mineral changes in young women with hypothalamic amenorrhea treated with oral contra­ ceptives, medroxyprogesterone, or placebo over 12 months. a m j o bstet gynecol 19 97 ; 176, 1017-25. 21. huddleston a , rockwell d , kulund d n & harrison b. bone m ass in lifetime tennis athletes. j a m a 19 80 : 8 4 4 ( 1 0 ) , 1107-9. 22. johnston gc, slemenda c\v & melton lj. clinical use o f bone densitometry. x engl j med 19 91 : 3 2 4 , 1105-9. 23. jonnavithula s, warren mp, fox r p & lazaro mi. bone density is compromised in amenorrheic women despite return o f menses: a 2-year study. o bstet gynecol 1 9 9 3 :8 1 , 669-674. 24. kannus p, haapasalo h, sankelo m, sievanen h , postmen m, heinonen a , oja p & vuori i. effect o f starting age o f physical activity on bone mass in the dominant arm o f ten­ nis and squash players. a n n intern med 19 95 ; 123, 27-31. 25. karlsson m k, johnell o & obrant k j. is bone mineral den­ sity advantage maintained long-term in previous weight lifters. calcif tissue int 19 95 ; 57, 325-8. 26. keen a d & drinkwater bl. irreversible bone loss in former amenorrheic athletes. osteoporosis int 1 9 97 ; 7, 311-5. 27. kerr d a , morton a , dick i & prince rl. exercise effects on bone mass in postmenopausal women are site specific and load-dependent. j bone and miner r es 1 9 9 6 ; 11, 21 8 225. 28. lloyd t, myers c, buchanan jr & demers lm. collegiate women athletes with irregular menses during adolescence have decreased bone density. obstet gunecol 1988; 72, 639-42. 29. lohman t, going s, pamenter r, hall m, b oyden t, iloutkooper l, ritenbaugil c, dare l, hill a & aickin m. effects o f resistance training on regional and toted bone mineral density in premenopausal women: a randomized prospective study. j bone miner r es 19 95 ; 10, 1015-24. 30. lutz j. bone mineral, serum calcium, and dietary intakes o f mother/daughter pairs. a m j clin nutr 1 9 86 ; 44, 99 106. 31. marcus r, cann c, madvig p, minkoffj, goddard m, bayer m, martin m, gaudiani l, haskell w & genant h. menstrual fiinction and bone mass in elite women distance runners: endocrine metabolic features. a n n intern med 1 985: 102, 158-63. 32. matlcovic v, jelic t, wardlaw gm, ilich jz, goel pk, wright jk, andon mb, smith k t & h eaney r p timing of peak bone mass in caucasian females and its implications for the prevention o f osteoporosis. j clin invest 1 9 94 ; 93, 799-808. 33. mazess r b & barden hs. bone density in premenopausal women: effects o f age, dietary intake, physical activity, smoking, and birth-control pills. a m j clin nutr 19 91 ; 53, 132-42. 34. micklesfield lk, lambert ev, fataar a b , noakes td & myburgh k h . bone mineral density in mature, p re­ menopausal, ultramarathon runners. med sci sports exerc 1 995; 27, 688-96. 35. micklesfield l k , reyneke l, fataar a & myburgh kh. long-term restoration o f deficits in bone mineral density is inadequate in premenopausal women with prior menstrual irregularity. clin j sports med 19 98 ; in press . 36. morris fl, naughton g a , gibbs jl, carlson js & warlc jd. prospective ten-month exercise intervention in preme narchel girls: positive effects on bone and lean mass. j bone miner res 19 97 ; 1 2 ( 9 ) , 1453-62. 37. mosekilde l, mosekilde l & danielsen cc. biomechanical competence o f vertebral trabecular bone in relation to ash density and age in normal individuals. bone 1987; 8, 79-85. 38. otist c.l. exercise-associated amenorrhea. clin sports med 1992; 11 ( 2 ) , 351-61. 39. parjit m. the two faces o f growth benefits and risks to bone integrity. osteoporosis int 1994; 4 ( 6 ) , 382-98. 40. parfitt a m . genetic effects on bone mass and turnover-rel evance to black/w h ite differences. j a m college o f nutrition 1997; 1 6 ( 4 ) . 325-33. 41. pearce g. bass s. young n, formica c & seeman e. does weight bearing exercise protect against the effects o f exer­ cise induced oligomenorrhea on bone d en sity? osteoporosis int 1996; 6, 448-52. 42. prior jc, vigna ym, schechter mt & burgess a e . spinal bone loss and ovulatory disturbances. ;y engl j med 1990: . 3 2 3 ( 1 8 ) , 1221-7. 43. recker rr, davies k , hinders sh, heaney rp, stegman mr & kimmel d b . bone gain in young adult women. j a m a 1992; 26 8, 2403-8. 44. renclcen ml, chesnut i i i c h & drinkwater bl. bone den­ sity at multiple skeletal sites in amenorrheic athletes. j a m a 1996; 2 7 6 ( 3 ) , 238-40. 45. risser wl, lee ej, leblanc a , poindexter gbw, risser j m h & schneider v. bone density in eumenorrheic female college athletes. med sci sports exerc 1990; 2 2 ( 5 ) , 570-4. 46. robinson tl, snow-harter c, taaffee dr, gills d, shaw j & marcus r. gymnasts exhibit higher bone mass than run­ ners espite similar prevalence o f amenorrhea and oligomen­ orrhea. j bone miner r es 1 9 95 ; 1 0 ( 1 ) , 26-35. 47. rockwell jc, sorensen a m , baker s, leahey d, stock jl, michaels j & baran dt. weight training decreases verte­ bral bone density in premenopausal women: a prospective study. j clin endocrinol metab 1 9 90 ; 71 ( 4 ) , 988-92. 48. salamone lm, glynne nw, black dm , ferrell re, palermo l, epstein rs, kuller l h & cauley j a . determinants o f premenopausal bone mineral density: the interplay o f genet­ ic and lifestyle factors. j bone miner res 1996; 1 1 ( 1 0 ) , 1557-65. 49. schonau e, wentzlik u, dietrich m, scheidhauer k & klein k. is there an increase in bone density in children? lancet 1 9 93 ; 342, 689-90. 50. seeman e, hopper jl, bach l a , cooper me, parkinson e, m ck a y j & jerums g. reduced bone mass in daughters o f women with osteoporosis. n eng j med 1989; 3 2 0 ( 9 ) , 554-8. 51. seeman e. reduced bone density in women with fractures: contribution o f low peak bone density and rapid bone loss. osteoporosis int suppl 1994; 1, s15-25. 52. slemenda c & johnston c. high intensity activities in young women: site specific bone mass effects among female figure skaters. bone miner 1993: 20, 125-32. 53. snow-iiarter c. bouxsein jl, lewis bt, carter d r & marcus r. effects of resistance and endurance exercise on bone mineral status o f young women: a randomized exercise intervention trial. j bone miner r es 1992; 7 ( 7 ) . 761-9. 54. theintz g, buchs b, rizzoli r, sloman d, clavien h, sizonenko p & bonjour j. longitudinal monitoring o f bone mass accumulation in healthy adolescents: evidence for a marked reduction after 16 years of age at the levels o f the lumbar spine and femoral neck in female subjects. j clin endocrinol metab 1992: 7 5 ( 4 ) , 1060-5. 55. torgerson d, campbell m k & reid dm. life-style, environ­ mental and medical factors influencing peak bone mass in women. br j rheum 1995; 34, 620-4. 56. trotter m & huron bb. sequential changes in weight, den­ sity, and percentage ash weight o f human skeletons from an early fetal period through old age. a nat r ec 1974; 179, 18 . 57. welten dc, kemper iic g , post gb, van mechelen w, twisk j, lips p & teule gj. weight-bearing activity during youth is a more important factor for peak bone mass than calcium intake. j bone miner r es 1994; 9 ( 7 ) , 1089-96. □ 8 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) research article the force absorption and rebound characteristics of cricket batting pads at four impact velocities r stretch1 d phil e du toita d phil t edwards2 ba(hons) b pretorius1 msc ' sport bureau, university o f port elizabeth; ^department o f human movement science, university of port elizabeth; “department o f mathematical statistics, university of port elizabeth abstract objective: an experiment was conducted to compare the ability to absorb impact forces and rebound char­ acteristics of an “ experimental” pair of pads with three pairs of cricket batting pads currently in use. design: the forces absorption and rebound character­ istics of the “ experimental” (pi) pair of pads was com­ pared with three pairs of cricket batting pads (p2, p3 and p4) currently in use, at four impact velocities. slow'-medium (s i) (15.34 m .s 1), fast-medium (s2)(22,97 m .s1), fast (s3x30.68 m .s1) and express (s4x34.45 m .s1). these pads all showed differences in their structure and composition, with pi manufactured from a polyurethane compound, while the inner part of p2, p3 and p4 was made of padding strengthened by a cane or plastic reinforcement rod, as well as a second spongy inner layer. the impact forces were measured using the drop test where a weighted ball was dropped vertically onto the surface o f the batting pads with the vertical forces (n) measured on a kistler piezoelectrical multicomponent type 9281 a l l force platform. the rebound characterstics were determined by measuring the distance (m) the ball rebounded off the pad when delivered from a brell bowling machine. the twoand one-way analysis of variance, with fisher’s method of multiple comparison, were used to test for significant differences (p<0.01) between the pads at the four impact velocities and scheffe simulta­ neous confidence intervals were used to calculate the contrast in tlie pads. setting: this was a laboratory based test carried out in the biokinetics centre, department of human movement studies. results: the assessment of the force absorption char­ acteristics showed that pi was significantly' better at correspondence: dr richard stretch sport bureau university of port elizabeth po box 1600 port elizabeth 6000 tel: 041-5042584 fax: 041-532605 email: sparas@upe.ac.za absorbing the impact forces than all other pads at all impact velocities, with the exception of similar charac­ teristics shown to p2 at s3 and s4. at the faster impact velocities, pi and p2 showed similar force absorption characteristics, which were significantly' better than both p3 and p4. the assessment ofthe rebound char­ acteristics show'ed that pi produced significantly' greater post-impact rebound distance at all impact velocities. at the faster velocities p4 show'ed signifi­ cantly smaller rebound characteristics than pi and p3, with similar scores to p2 at s3. p2 show'ed significant­ ly smaller rebound distance to p4 at s4. conclusions: the results showed significant differ­ ences between the impact kinetics of the cricket bat­ ting pads at various impact velocities. these differ­ ences were as a result of the differences in the struc­ ture and composition of the protective part of tlie pads, with some pads better able to absorb the impact forces of the ball providing the batsman with greater protec­ tion. further, a number o f other factors that need to be taken into account w'hen choosing pads or in the man­ ufacturing thereof, were highlighted. keywords: cricket, equipment, force absorption, rebound, kinematics introduction deaths from cricket date as far back as 1751 w'hen, according to cricket lore, the passing of frederick louis, the prince of wales and father of george iii, died hours after being struck on the head by a cricket ball.1 it has been suggested that six deaths per year occur in the united kingdom as a result of playing cricket.2 besides back injuries to fast bowlers, the major areas of concern to players, coaches and administra­ tors are impact injuries while batting, particularly' to the head and face and the fingers.1a4s the head and facial injuries were primarily as a result of being struck by the ball while batting without a helmet or with a helmet with ear-pieces only and included concussions, broken nose and cheek bones and lacerations requiring stitches, around the eyes, mouth and chin. four of the eve injuries were as a result of the ball deflecting off the top edge of the bat w'hile hooking and striking the eye on the side of the dominant hand.1* injuries to the fingers, as a result of impact from the ball, were found to be the most common w'hile batting.i :i 4,5 protective equipment such as batting gloves and sports medicine october 1998 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:sparas@upe.ac.za pads have been used for well over a century, while dur­ ing the last two decades the batting helmet has become a standard part of the batsman’s protective equipment. however, only two studies have aimed at evaluating this protective equipment in a sport where a solid ball with a mass 156g is propelled towards the batsman from a distance of approximately 18m at speeds up to 38m/s. both studies recommended that the equipment manufacturers need to increase the pro­ tection offered by the batting glove.7-8 an investigation into the shock absorption of crick­ et batting pads in order to determine which factors influence the shock absorption capabilities and their ability to conform to standards showed adequate impact resistance was provided around the shin and ankle.8 six of the eleven pads did not meet the require­ ments for repeated drops on the knee roll, particularly for the higher temperature and humidity conditions. a high correlation was found between the peak decel­ eration and knee roll and shin thickness. higher tem­ perature and humidity had a negative effect on the force absorption characteristics, while the construction and pad thickness significantly improved the shock absorption characteristics. lower limb injuries occurring while batting were mainly hamstring, quadriceps and calf muscle pulls as a result o f running between the wicket.14”7 9 although the literature does not report any serious impact injury to the protected part o f the lower limbs, which may suggest that batting pads offer adequate protection, cricket equipment manufacturers continually need to assess new designs and material from which to manu­ facture their protective equipment. the final product not only has to meet the legal requirements of the sport, but has to balance the a mount of protection offered to the batsman with a number of factors that may enhance or inhibit performance. these may include the following: comfort required to wear this protective equipment for long periods at a time; the pads need to be light so as not to have a negative effect on the running speed between die wickets; during 3-5 day matches where there are usually a number of field­ ers in catching positions in close proximity to the bats­ man it' would be advantageous if the pads have a low ball-pad coefficient of restitution reducing the risk of “bat-pad” catches (the ball deflecting from the bat onto the pads and then caught by a fielder), while in limited-overs matches, where there are seldom field­ ers in close catching positions, the converse would apply whereby batsman may gain an advantage if the pads have a high ball-pad coefficient of restitution and can score runs or leg-byes from balls striking the pads. following on the assessment of the force absorption characteristics of cricket batting gloves by stretch and tyler (1995), the experiment aimed to evaluate and compare the force absorption and rebound characteris­ tics o f four pairs of cricket batting pads at various impact velocities and to compare a “ new” pair of crick­ et batting pads with cricket batting pads currently in use. secondly, the experiment sought to identify rea­ sons, if any, for differences in the impact kinetics in order to assist manufacturers to modify batting pads to suit the modem game. m e t h o d s one “ experimental” (pi) and three pairs of cricket bat­ ting pads that are currently in use (p2, p3 and p4), supplied by different manufacturers, were used in this study to test the force absorption and the rebound characteristics of cricket batting pads. the structure and composition of the protective part of the pads dif­ fered in all four makes of the pads assessed. all the pads had two protective components, the outer protec­ tive layer that offered protection to die lower leg, knee and part of the upper leg, and a spongy padded layer that fitted inside the pad offering additional protection to the front of the lower leg. the part of pi and p3 below and above the knee was made up of nine vertical segments or ‘rolls’, while that of p3 and p4 consisted of eight segments. at the knee area p2, p3 and p4 were similar with three horizontal segments or ‘rolls’, while pi was made up of five horizontal segments. the outer part of the pi consisted of a solid polyurethane com­ pound, while that of p2, p3 and p4 was made of padding strengdiened by a cane or plastic reinforce­ ment rod in each of the ‘rolls’. the second protective layer of the pads was very similar in thickness, size and composition, being made o f a spongy layer. the impact velocities used for both experiments were based on release velocities10, talcing into account a 14,3%“ decrease in the ball velocity by die time it reaches the batsman. these were classified as slow medium (si), fast-medium (s2), fast (s3) and express (s4) (table 1). the procedure used in the assessment of the force absorption characteristics of the four batting pads was based on die drop test.12 in this test the dropping mass falls onto die surface o f the batting pads (pi, p2, p3 and p4) at four impact velocities (si, s3, s3, and s4), widi the vertical forces measured by a kistler piezoelectrical multicomponent type 9281 a l l force platform (f igure 1) installed and calibrated to die manufacturer’s specification. by means of the piezoelectrical transducers an electric voltage, for the determination of the force exerted on die force plat­ form, was obtained. a kistier electronic amplifier type 9805 was attached to the piezoelectrical force platform by means of a 9-core cable in order to determine the force die ball exerted through the pads onto the force table i: release and impact velocities o f the ball under match conditions and the calculat­ ed mass o f the experimental “ball” release velocity impact velocity (m.s1) (m.s1) (abemcthv, 1981) (penrose et al 1976 imass of experimental “ball” (g) slow-medium (si) 17.9 15.3 fast-medium (s3) 26.8 23.0 fast (s3) 35.8 30.7 express (s4) 40.2 34.5 630.8 944.4 1262.8 1416.6 10 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) platform. tlie voltage changes received from the piezo­ electrical transducers passed through the amplifier to the computer which was fitted with an analogue to dig­ ital converter card (ec. 30) to convert the impulses for storage and later retrieval and analysis. figure 1: experimental set-up for measuring the force absorption characteristics o f the cricket batting pads. the impact velocity of tlie ball under match condi­ tions was simulated using an experimental “ball” which was weighted and dropped vertically onto the batting pad from a height of 1 metre. the weight of the experimental “ball” was determined as described below: the impact momentum of the ball under match condi­ tions for the different impact velocities was computed from tlie following: momentum = inv (i) where: m = mass of ball (156 g) v = velocity of tlie ball at impact from table i the velocity of the experimental “ball” dropped from a height of 1 metre was computed from the following: velocity = 2gd (ii) where: g = gravity (9,8050 m/s~) d = distance which remained constant at 1 metre the mass of the experimental “ball” dropped from a height of 1 metre was computed from the following: mass = p/v where: p = impact momentum o f the ball at various impact velocities under match conditions, calculated from (i) v = velocity of ball at impact, calculated from (ii) the pads were positioned on the force platform so that impact woidd occur just below the knee. at this site all the manufacturers ensured that maximum protection occurred by providing additional padding on the inside of the pad. the testing of the cushioning properties for one pad was carried out at all four impact velocities, before proceeding to die next pad. this ensured that the positioning of the pads for tlie various impact velocities was constant. each pad was subjected to fif­ teen impacts with tlie weighted “ball” at si, s2, s3 and s4 in order to simulate impact of the four release velocities. the procedure used in tlie assessment of the rebound characteristics of the four batting pads required a cricket ball to be projected by a brell bowling machine at four release against tlie batting pads, with the rebound distance measured (figure 2). the bowling machine velocities were determined according to the guidelines set out by the manufactur­ er (table 2). the following bowling machine settings were used: si was set at number 3, s2 was set between number 4 and 5, s3 was set between number 5 and 6, and s4 was set between number 6 and 7. the bowling machine projected a kookaburra ball (156g) onto an artificial surface (astroturf) and then onto the pad which w'as positioned 3m aw'ay so that the angle of approach w'ould be as close to 45" as possible. the pad w'as strapped onto a prosthesis wliich w'as secured onto a stable base and positioned at an angle of 90" to hie testing surface. the small ball flight distance, as w'ell as tlie securing of the pads in position, ensured a con­ stant angle of approach of the ball prior toimpacting the pad. the rebound distance of tlie ball was mea suredusing a tape measure positioned along the length of the cricket pitch. in addition, hie testing procedure w'as video taped and the rebound distance w'as verified from this recording. the testing of tlie rebound char­ acteristics for all four pads w'as carried out at si, before adjusting tlie bowling machine speeds to s2, s3 ands4. this ensured that tlie pre-impact ball velocity w'as kept constant for the different pads. figure 2: experimental set-up for measuring the rebound characteristics of the cricket batting pads. tlie statistical package minitab11 and sas w'ere used to compute single variable statistics and the fol­ lowing statistical tests and graphical tools aided in table ii: brell bowling machine release velocities bowling machine setting release velocity (km/h) (m .s1) 1 45.58 12.66 2 54.40 15.11 3 65.70 18.25 si 4 80.90 22.47 s2 5 102.98 28.61 s3 6 135.52 37.64 s4 7 182.25 50.63 sports medicine october 1998 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) checking the validity of the tests and to test the force absorption and rebound differences between the vari­ ous batting pads at each o f the four impact velocities. • a one-way analysis o f variance was used to examine whether any inter-pad differences occurred or whether tlie pads showed similar impact character­ istics at tlie different impact velocities, with the fisher method of multiple comparisons used to establish the significant differences, • a two-way analysis of variance w'as conducted to test for significant interaction between the four pads and the different impact velocities, and • scheffe simultaneous confidence intervals w'ere cal­ culated to examine a contrast in the four pads. the one percent level o f significance was used for all tests and confidence intervals. results the mean force absorption and rebound characteris­ tics for the different batting pads at the four velocities are shown in table 3. the one-way analyses of variance carried out on the data showed significant differences between the four pads for both rebound distance (f=5.81) and force absorption (f=7.80). the confidence intervals generated by fisher’s method indicate the significant differences (table 4). table iii: force absorption (n) and rebound distance (m) values for the cricket batting pads at the various impact velocities force absorption (n) rebound distance (m) mean sd mean sd speed 1 pi 43.34 3.08 7.84 0.19 p2 51.04 3.67 7.44 0.12 p3 59.18 3.02 7.45 0.15 p4 59.89 2.91 7.16 0.09 speed 2 pi 69.61 3.00 9.27 0.20 p2 75.56 2.45 8.11 0.12 p3 87.88 2.47 8.64 0.15 p4 88.19 3.93 8.01 0.07 speed 3 pi 91.23 3.36 11.06 0.43 p2 91.60 2.60 10.07 0.11 p3 104.20 3.86 10.49 0.08 p4 107.45 5.88 10.07 0.08 speed 4 pi 108.13 4.40 12.52 0.19 p2 106.27 3.43 10.89 0.09 p3 120.97 4.62 11.54 0.31 p4 25.21 4.24 11.13 0.12 the assessment of the force absorption characteris­ tics showed that pi was significantly better at absorb­ ing the impact forces than all other pads at all four impact velocities, with the exception of similar charac­ teristics shown to p2 at s3 and s4. when comparing pi and p2, pi showed significantly better ability to absorb impact forces at the slower velocities than p2, with similar results recorded at the faster velocities (s3 and s4). p2 show'ed significantly better force absorption characteristics to p3 and p4 at all the impact veloci­ ties. p3 and p4 showed similar force absorption abili­ ties at si, s2 and s3, with p3 reflecting better force absorption characteristics at the fastest velocity (s4). at the slower velocities pi show'ed significantly greater ability to absorb the impact forces than p2, p3 and p4. at these slower impact velocities p2 was sig­ nificantly better than both p3 and p4, while similar force absorption characteristics were found for p3 and p4. at the faster impact velocities, pi and p2 showed similar force absorption characteristics, which were significantly better than both p3 and p4. table iv: summary of the fisher multiple compari > son test for the force absorption and rebound distance of the cricket batting pads force absorption rebound distance pi p2 p3 pi p2 p3 speed 1 p3 -10.81* -4.60 p3 -18.95* -11.25* 25.49* 53-84 24.49* -15.18 -12.74 5.04 52.84 13.18 p4 -19.66* -11.96 -3.812 54.16* 14.49* 15.49* -13.45 5.75 2.40 82.51 42.84 43.84 speed 2 p3 -8.89* -3.00 p3 -21.22* -15.27* 101.82 130.45 49.15 * t -66.98* -15.32 -9.38 7 7 .7 8 -38.35 p4 -21.53* -15.58 3.26 112.15* -3.98 48.68* -15.63 9.69 2.64 140.78 24.65 77.32 speed 3 p2 -3.70 4.30 p3 -16.30* -16.60* 77.14* 122.19 34.81* -64.86* -8.29 8.60 79.86 -19.81 p4 -19.54* -19.85* -7.25 76.81* -22.86 19.47* -11.54 -11.84 0.76 121.86 22.19 64.53 speed 4 p2 -2.22 5.95 p3 -16.93* -18.79* 142.94* 181.72 78.61* -83.72* 8.76 -10.62 117.39 -44.94 p4 -21.17* -23.03* -8.32* 118.94* -43.39* 20.94* -13.00 -14.86 -0.15 157.72 -4.61 5 9 .7 2 *siynificant difference (p<0.01) 12 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) at all four velocities pi recorded a greater post impact rebound distance than the other pads. p2 showed similar rebound distances to p3 at si and to p4 at s2 and s3. p2 showed rebound distances that were significantly greater than p4 at si and signifi­ cantly smaller than p3 at s2, s3 and s4, and p4 at s4. p3 was significantly greater than p4 at all the impact velocities, while p4 was significantly smaller than all the pads at all four the impact velocities, with the exception o f recording similar rebound distances to p2 at s2 and s3. at the slower velocities p4 showed a sig­ nificantly smaller rebound distances than pi, p2 and p3, with the exception of similar scores to p2 at s2. p3 recorded significantly smaller values than pi at si and s2 and p2 at si. p2 and p3 showed similar rebound characteristics at si. at the faster velocities p4 showed significant!}7 smaller rebound characteristics than pi and p3, with similar scores to p2 at s3. p2 showed significantly smaller rebound distance to p4 at s4. further investigation yielded that the 99% scheffe simultaneous confidence intervals for the contrast that involved a comparison o f p2 with the other three pads, were significant at s2, s3 and s4, indicating that the force absorption and rebound distance characteristics of this pad rated the best. p2 did not differ sigffifi cant.ly from the other pads at si. discussion the principal finding of this study was that there is a significant difference between the impact kinetics of die cricket batting pads at various impact velocities. these differences would be as a result of the differ­ ences in die structure and composition of die protec­ tive part of the pads, widi some makes of pads better able to absorb the impact forces of the ball providing the batsman greater protection, while others were bet­ ter able to reduce die rebound distance of the ball after impact. from die findings it would appear diat die batting pads best able to absorb the impact forces of a ball bowled at fast to express velocities would be diose manufactured from a polyurethane material (pi). a second advantage, aldiough not tested experimentally, is that these pads are very7 light and comfortable to wear and as a result they should not have as great a negative effect on the running speed of the batsman as die heavier pads currendy used. in limited-overs crick­ et where an off-field umpire uses slow motion tv replays to decide whether a batsman is run-out or not, the player who runs fast between the wickets has a dis­ tinct advantage and the success or failure often depends 011 die speed with which he is able to run between the wickets. the pads that are currendy in use have a greater ability7 to reduce the rebound distance of the ball after impact with the pads. this reduced ball-pad coeffi­ cient of restitution would be as a result of die structure and composition of the protective parts of the pads which are less rigid.however, the rebound characteris­ tic of the pads could eidier be an advantage or a dis­ advantage when batting, depending on the type of match and the match situation. li test cricket, where it is more common for fielders to field in close proxim­ ity to the batsman, pads widi a large post impact rebound distance of the ball could result in the bats­ man being caught “bat-pad” (die ball deflected from die bat onto the pads and then being caught by a field­ er). wearing the more traditional pads, which showed smaller rebound distance, would reduce this rebound distance thus reducing the risk o f dismissal in this manner. hie converse could, however, apply in limited overs cricket matches where the fielders are normally a distance from the batsman. the batsman wearing pads with a greater post-impact rebound distance may have an advantage by being able to score runs or leg-byes from balls deflecting off the pads. a disadvantage of pi, aldiough not tested experi­ mentally, was that the ball striking the pad made a sim­ ilar sound to that of a ball striking the bat and could result in a batsman being incorrecdy adjudged caught by7 the wicketkeeper or fielder. the manufacturers are, however, hi the difficult position o f having to balance the impact absorption and rebound characteristics of the pads widi the comfort required to wear them for long periods at a time. cricket pad manufacturers, aware that the batting pads behave differentiy7 under various impact conditions due to the structure and composition of the protective lay7 ers o f die pads, need to further investigate the impact properties of the components or combinations of com­ ponents they use in their batting pads. only through continual research in the design and composition of the materials used in the manufacture of batting pads, will die players gain maximum protec­ tion and comfort. references 1. temple r. cricket injuries: f ast pitches change the gentleman’s sport. pliys sportsmed 1 9 8 2 :1 0 ( 6 ) :1 86-19 2. 2. blonstein jl. medical aspects o f amateur boxing. proc r soc med 19 66 ;59 :64 99. 3. stretch r a . injuries to south african cricketers playing at first-class level. sports med 1 9 8 9 :4 (i) :3-20. 4. stretch r a . the incidence and nature o f injuries in first league and provincial cricketers. s a fr m ed j 1 9 9 3 ;8 3 (5 ) -.339-342. 5. stretch r a . the seasonal incidence and nature o f injuries in schoolboy cricketers. s a fr med j 1 9 9 5 ;8 5 (1 1 ):1 1 8 2 -1 1 8 4 . 6. jones np, tidlo a b . severe eye injuries in cricket. b r j sports med 19 8 6 ;2 0 ( 4 ) : 1 78-179. 7. stretch r a , tyler j. the force absobtion characteristics o f cricket batting gloves at four impact velocities. s a fr j sports med 1 9 9 5 ;2 ( 3 ) :2 2 © 2 9 . 8. hyrosomallis c. shock absorption o f cricket leg guards and batting gloves. paper presented at australian conference o f science and medicine in sport, national convention centre,canberra, australia. 1996. 9. payne \vr, h o y g, laussen sp, carlson js. what research tells the cricket coach. sports coach 1 9 8 7 ;1 0 (4 ) -.17-22. 10. abernethij b. mechanism o f skill in cricket batting. a u s t j sport 1 9 8 1 ;1 3 ( 1 ) :3 -w . 11. penrose t, foster d , blanksbg b. release velocities o f fast bowlers during a cricket test match. supplement to a u st j health phys ed rec. 1976:71:2-5. 12. nigg bm. the validity and relevance o f tests used for the assessment o f sports surfaces. med sc sport exercise 1 9 9 0 :2 2 (1 ) :1 31-13 9. □ sports medicine october 1998 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) research article comparison of oral and infrared auditory canal thermometry in sports participants a fuller (bsc hons) d mitchell (phd) department o f physiology, university o f the witwatersrand, medical school, parktown 2193 . abstract objective: to investigate whether recently developed infrared auditory canal thermometers, which offer numerous advantages over conventional oral glass mercury thermometers, provide measurements equiv­ alent to those of the oral glass-niercurv thermometers before and after exercise. design: open trial setting: sporting arenas and gymnasiums. interventions: oral (t,„.,|) and auditory canal tempera­ tures (tuc) were recorded in 45 adult persons partic­ ipating in one of four sports; field hockey, squash, high-impact aerobics or swimming. results: t.1(. correlated linearly with toral before and after exercise, but there was considerable variability between the two measures o f body temperature, with upper and lower 95 % prediction intervals determined over the range o f tac differing by at least 2 "c. although we did not measure core body temperature, post-exer­ cise measurements of tac and tonl] did not indicate tlie expected rise in body temperature, and both sites appear to underestimate blood temperature. in addi­ tion, the ear canal thermometer recorded anomalously low readings of post-exercise tolal at the site o f tlie swimming pool. conclusions: our data indicate that the relationship between auditory canal temperature and oral tempera true is variable and unpredictable in sports partici­ pants. audi ton' canal thermometry is unlikely to offer an improvement on oral thermometry for tlie screening of body temperatiue in tlie sports arena. key words: body temperature; exercise; tympanic membrane temperatiue; hyperthermia introduction hyperthermia and hypothermia constitute serious health risks, both for the elite athlete and the recre­ ational sportsperson. management of the risk requires the measurement of core body temperature, which is a particularly formidable logistic problem when events can attract tens o f thousands o f participants. numerous techniques have been used, clinically and in the laboratory, to monitor body temperature. the gen­ eral thermal status o f tlie body is best represented by correspondence: andrea fuller department of physiology university of the witwatersrand, medical school 7 york road, parktown, 2193 johannesburg, south africa tel: 0 1 1 6 4 7 2363 fax: o il 643 2765 e-mail: 127and y@cli iron. wi t.s .ac. za the temperatiue of mixed venous blood in the right ventricle or pulmonary7 artery.316 however, temperatiue measurement at this site necessarily is invasive and usually is carried out only in critically ill patients. other estimates of body core temperature trade off accuracy against practical considerations of conve­ nience and compliance, hi tlie spoils arena, especially when there are multiple participants, one is con­ strained to use measures, at least for the primary screening of body core temperatiue, which forfeit accu­ racy for convenience. even though it is documented that sublingual oral temperatiue (t<)rill) is not a good index of blood temperature,"1 it is die measiue of body temperature most commonly used in sports partici­ pants; it is used because it is convenient and socially acceptable. however, measurement of toral requires the voluntary co-operation of die subject and careful probe placement.7 glass-mercury thermometers are associat­ ed with risks of mercury spillage and cross-infection, and are slow, requiring at least three minutes of closed-moudi measurement and providing maximum accuracy after about eight minutes.12 furthermore, the accuracy of the reading, which is not good at best, can be influenced adversely by the ingestion of liquids, gum chewing, and open moutii breadiing.7222'' recendy, “ tympanic membrane” thermometers have become available commercially, at relatively low cost, and are being used increasingly in hospitals. these instruments record infrared radiation emitted from the tympanic membrane or, more usually, die ter­ minal auditory canal, and offer several practical advan­ tages over other devices used for body temperature measurement. tlie tiiemiometers are non-invasive, easy to use, and provide a digital display of tempera­ ture in a few seconds.22 unlike oral thermometers, auditory canal dierniometers are not influenced by recent liquid ingestion or inadvertent mouth opening,23 and there is no discomfort or risk of infection for sub­ jects. h ie usefulness of diese thermometers has been demonstrated in pediatric patients, intensive care unit patients, nursing home residents, outpatients, and research laboratories.022 tlie potential o f the infrared auditory canal diennometer to simplify and shorten the process of temperature measurement makes it an appealing device for use in sports participants. if it is to be a viable sports thermometer, it should be no less accurate than the conventional oral thermometer. as with the oral thermometer, the auditory canal ther­ mometer cannot be used to monitor the temperature of a person widi heat illness, where a better measiue of body core temperature is required; its role might be to screen for those sports participants who require more intensive monitoring. the purpose of our study was to determine whether die infrared auditory canal thermometer provides measurements equivalent to those of the oral glass mercury diennometer before and after exercise. we compared auditor}' canal and oral temperature mea­ surements in adults participating in a variety of sports. 14 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) methods toiai and auditory canal temperatures (tac) were recorded in subjects participating in four sports, at dif­ ferent times of day; field hockey, squash, high-inipact aerobics, and swimming. in total, 45 health}' subjects volunteered, and their ages are show'll in table i. the protocol for our study was approved by the committee for research on human subjects, university of the witwatersrand. table: i subject ages age (yr.) sport mean ± sd range hockey (n = 11) 20.5 ± 1.4 18 23 squash (n = 10) 21.0 ± 1.2 19 23 aerobics (n = 12) 22.8 ± 2.8 20 30 swimming (n = 12) 22.9 ± 8.2 18 48 we measured tol.a] using a glass-mercury ther­ mometer placed in the subject’s posterior sublingual pocket for three minutes. during this period, tac was recorded using an infrared thermometer, the genius firsttemp model 3000a (intelligent medical systems, carlsbad, ca). auditory canal temperatures were recorded in both ears, first in the right ear and imme­ diately thereafter in the left ear. temperatures were measured according to the manufacturer's instruc­ tions; the subject’s head was gently restrained while the probe tip was inserted far enough into the ear canal to seal the tympanum from ambient air. to min­ imise operator variability, tac was measured by a single investigator. the subjects rested at ambient tempera­ ture, at die site of subsequent activity, for at least five minutes before we recorded rest temperatures. post­ exercise temperatures were recorded within two min­ utes after completion of exercise. swimmers did not towel-dry themselves until both tuc and toral had been measured; their ear canals were, however, dried before measurements of tac were taken. the duration of exer­ cise for each sport (excluding warm-up time) was 70 minutes for hockey, 50 minutes for squash, 60 minutes for aerobics and 25 minutes for swimming. post-exer­ cise temperatures were not obtained from three sub­ jects for technical reasons. the glass-mercury thermometers and the auditory canal thermometer were calibrated after completion of the study, against a high accuracy quartz thermometer (quat 100/200, heraeus, hanau, germany). the oral thermometers were immersed in an insulated water bath set at a variety of controlled temperatures. the auditor}7 canal thermometer was pointed at an infrared black body, constructed as a matt black re-entrant cone set up in the water bath. when calibrated, both the auditory canal thermometer and the oral thermome­ ters had an accuracy of better than 0.1 ’c over their measurement ranges. dr}7 and wet-bulb ambient temperatures were mea­ sured at 10-minute intervals at each sports site using a sling psyclirometer. a psychrometric chart was used to calculate vapour pressure and relative humidity. environmental conditions at each site are shown in table ii. the heated swimming pool was located indoors in a health club complex, and pool tempera­ ture was about 25 'c. table ii: environmental conditions (mean ± sd, n = 4 to 8) sport tdh twb rh vp cc) cc) (%) (kpa) hockey 21.1 ± 1.1 12.1 ± 1.0 36 ± 4 0.9 ± 0.1 squash 21.0 ± 0.7 13.8 ± 0.4 46 ± 6 1.2 ± 0.1 aerobics 20.1 ± 0.5 13.7 ± 0.3 51 ± 2 1.2 ± 0.0 swimming 18.0 ± 0.1 15.0 ± 0.1 74 ± 1 1.5 ± 0.1 t jb = dry bulb temperature; tw|, = wet bulb temperature; r h = relative humidity7; vp = vapour pressure. the relationship between tai. and toral was evaluat­ ed using pearson product-moment correlation analyses and linear regression. values of p < 0.05 were consid­ ered significant. results left t.u: was significantly correlated with right tac at rest before exercise (r = 0.64, p < 0.0001, n = 45; left tac = 12.7 + 0.64 right tllc; right tuc = 13.2 + 0.63 left tac), and mean left tac (35.9 ± 0.5 °c) and mean right tac (35.9 ± 0.5 "o were the same. furthermore, the slope of a regression line forced tlirough the origin was not significantly different from one (figure 1), so there was no particular bias for one side of the head. however, only about 40 % of the variability7 in the audi­ tor}7 canal temperature of one ear was associated with variability7 in the other ear. measures of contralateral t.lc were not equivalent; the mean absolute difference between left tac and right tac was 0.3 ± 0.3 ‘c, and exceeded 1 *c for individual subjects. tac , in all further analyses, therefore was expressed as the mean of left tac and right t.lc. figure 1: left and right auditor}7 canal temperatures in the same subjects, at rest, before participation in sports events. the linear regression line (solid line) and 95 % prediction intervals (dashed lines) of an equation constrained to go through the origin are shown. (right tac = (1.00 ± 0.01) x left tac, r = 0.52, p < 0.0001, n = 45). mean oral and auditor}7 canal temperatures record­ ed for participants in each sport, both at rest and post exercise, are shown in table iii. mean oral tempera­ tures were typical of those usually recorded in young adults, in johannesburg. at rest, tuc and tonll were sig­ nificantly correlated (figure 2), with tolal somewhat sports medicine october 1998 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) higher than tac at tlie lower temperatures, and some­ what lower at the high temperatures. however, the upper and lower 95% prediction intervals differed by 2 ’c (figure 2), implying that at any tac , tornl could be substantially higher or lower than tac in individual subjects. table iii: oral (toral) and auditory canal (tac) temperatures o f subjects recorded before and after exercise (mean ± sd) toni, cc) sport rest post -exercise tac cc) rest post -exercise hockev 36.2 ± 0.4 35.5 + 0.5 36.0 ± 0.3 35.6 ± 0 5 (n = 10) squash 36.1 ± 0.5 35.8 ± 0.7 35.8 ± 0.6 35.3 ± 0.9 (n = 10) aerobics 35.8 ± 0.6 36.2 ± 0.6 35.7 ± 0.6 36.0 ± 0.5 (n = 11) swimming 35.9 ± 0.7 36.2 ± 0.9 36.0 ± 0.5 33.6 ± 0.7 (n = 11) figure 2: oral temperature (tnrai) as a function of audi­ tory' canal temperature (tac, mean of both canals) in subjects at rest before exercise. the linear regression line and 95 % prediction intervals are shown. (toral = 0.63 tac + 13.3, r = 0.56, p < 0.001, n = 45). post-exercise temperatures for hockey, squash and aerobics participants are shown in figure 3. both tac and torai tended to drop (luring the sports events. tac and torati for all three sports considered together, were still significantly correlated after the events. as with rest temperatures, variability between tac and t()ral of individuals was considerable, with the upper and lower 95 % prediction intervals differing by between 2.2 and 2.4 "c over the range of measured temperatures (figure 3). the mean tac measured after swimming was very low (33.6 + 0.7 so the temperatures after swim­ ming were analysed separately. measurements o f tac and toral were significantly correlated (figure 4). however, tlie mean absolute difference between ta(. and toral was 2.6 + 0.6 "c, and the 95 % prediction intervals differed by between 2.9 and 3.3 ‘c over the range of measured tac. the greatest discrepancy between tac and tora| was therefore evident in swimmers. we configure 3: oral temperature (toral) as a function of audi­ tory canal temperature (tac, mean o f both canals), after exercise in hockey players (open circles, n = 10), squash players (open triangles, n = 10), and aerobics participants (closed circles, n = 11). the linear regres­ sion line and 95 % prediction intervals are shown. (toral = 0.48 tac + 18.8, r = 0.54, p < 0.005, n = 31). sidered the discrepancy too great to be the result sim­ ply of an inherent difference between the measure­ ment sites, and so measured tac in two observers, who had been at tlie poolside but not in the water; in both cases, tac was recorded as less than 34 ’c. figure 4: oral temperature (tonj) as a function of audi­ tory canal temperature (tuc, mean of both canals), after swimming. the linear regression line and 95 % predic­ tion intervals are shown. (toral = 1.01 tac + 2.4, r = 0.76, p < 0.01, n = 11). discussion the main aim o f our study was to determine whether temperatures indicated by an auditory canal ther­ mometer bore a defined relationship to those indicat­ ed by an oral thermometer, when the measurements were made simultaneously in sports participants. if that had been the case, the speed and convenience of the auditory canal thermometer would make it an attractive instrument for screening participants in events which impose a risk o f hyperthermia or hypothermia, replacing tlie oral thermometer, but not replacing the rectal, oesophageal or blood thermome­ 16 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ter necessary for moiiitoring the body core temperature of those with signs or symptoms of heat or cold illness. our results indicate that the relationship between auditory canal temperature and oral temperature is variable and unpredictable in sports participants, before and after their events. indeed, the results lead us to doubt whether either thermometer can be used safely to screen spoils participants. with neither thermometer does the problem he with an intrinsic inaccuracy of the measuring instru­ ment. when calibrated against a quartz thermometer, by water immersion in the case of the oral thermome­ ter and using a re-entrant cone blackbody in the case of the infrared detector in the auditory7 canal ther­ mometer, both thermometers achieved an intrinsic accuracy of 0.1 "c over the range of measured temper­ atures, better than necessary7 for physiological screen­ ing o f body temperature. li the case o f one sport, namely swimming, the main problem with the audito­ ry canal thermometer resulted from its failure to record temperatures properly in the field. for all sports, a second problem arose, namely physiological variability and inconsistency between the tempera­ tures indicated by the oral and auditory7 canal ther­ mometers. we detected the poolside problem with the audito­ ry canal thermometer through the anomalously low readings of post-exercise tac recorded at the site of the swimming pool (table iii). we believe that the infrared thermometer was adversely affected by water, either in the air or condensing, as a result of the high relative humidity (74 %), or because o f direct wetting (despite swimmers drying their ear canals). if water indeed caused the malfunction, sweat accumulation in the auditory7 canals of subjects may also affect the func­ tioning of the infrared thermometer. we recorded audi­ tory7 canal temperatures of less than 34.5 ‘c in three squash players who had sweated profusely (figure 3). we do not-know whether the problem is peculiar to the make of the thermometer we used, or whether it is a general problem o f all infrared auditory7 canal ther­ mometers. if it is a general problem, it is a serious deficiency; it not only would exclude the use of the thermometers for water sports (where hypothermia is the thermal risk), but also exclude them from use in environments where humidity contributes to the risk o f hyperthermia. that does not mean only hot humid environments; several football deaths have been reported when ta was below 24 'c, but the relative humidity exceeded 95 %.14 one of the physiological problems we encountered with the auditory7 canal thermometer was lack of bilat­ eral symmetry between the temperatures of the two ear canals. several papers describing the clinical use of auditory7 canal thermometers have claimed that the canals do have the same temperature, even in the pres­ ence of unilateral ear disease.11’ " 24 it may be that, in the clinical setting, the mean absolute difference of 0.3 "c between the two ear canals, which we observed, is considered tolerable. the criterion sometimes used to conclude that there is bilateral symmetry, namely that in a large group of subjects the mean difference between the two canal temperatures is not significant­ ly different from zero, clearly is an inappropriate use of statistics, and reflects only variability between the sub­ jects. we decided to use the average temperat ure of the two auditor}7 canals. the difference between that aver­ age temperature and oral temperature measured simultaneously was much greater than could be accounted for by the intrinsic inaccuracy of the ther­ mometers. despite similarities in mean temperatures (table iii) and statistical correlation between tac and torat (figure 2, 3 and 4), the oral glass-mercury and infrared auditor}7 canal thermometers yielded temper­ atures which were not interchangeable. in resting sub­ jects, only 31 % of the variance in tac was associated with the variance in t„ra|. furthermore, for any partic­ ular value of t.1c, tora, of an individual could be more than 1 ‘c above or below the mean expected value for the group (figure 2). during exercise there are changes in heat balance at the head, for example those resulting from open-mouth breathing and scalp sweat­ ing, and one would expect the relationship between tac and t(lra| to be even more variable than at rest. indeed, we found greater inconsistency in the relationship between tac and t(lral after exercise. for example, at tac just below 36 "c, oral temperature was below 35 "c in one hockey player and almost 37 "c in one aerobics participant. we therefore have to conclude that there is no fixed relationship between auditor}7 canal tem­ perature and oral temperature in sports participants, at least for the sports and conditions we investigated. the absence of a relationship between auditor}7 canal temperature and oral temperature could arise because either one, or both, of the sites at which the thermometers measure temperature have a tempera­ ture not consistently related to blood temperature. though we did not measure core body temperature, it is likely that neither site reflected blood temperature properly, since neither site demonstrated the expected rise in temperature associated with increased meta­ bolic heat production during exercise (table iii). although it continues to be used in the sports arena, oral thermometry has been known, for at least thirty years, to provide an unreliable index o f blood temperature during exercise.21 measurements of t(mll are lower than temperatures at deeper sites, in an inconsistent way, and are affected by both breathing patterns and ambient air temperature.12111 head skin temperature also has a strong influence on oral tem­ peratures,15 and low skin temperature could have con­ tributed to low oral temperature in the swimmers and when there was free evaporative cooling from the head. infrared auditory7 canal thermometers are much newer devices, and experience with them outside the hospi­ tal setting is limited.20-22 they are often referred to as infrared tympanic thermometers; the temperature at one particular site of the tympanum is thought by some to reflect the temperature of blood perfusing the brain.124 however, the genius thermometer which we used does not have the resolution necessary to mea­ sure temperature of the tympanic membrane only, and detects infrared radiation emanating from both the ear drum and the surrounding tissue, and the same is true for other makes o f infrared thermometer.0h auditory canal temperature is lower than tympanic membrane temperature (t,y).20 true tympanic temperature can be measured by placing either a thermistor or a thermo­ couple in direct contact with the ear drum. positioning of such a thermometer is a thoroughly unpleasant experience for subjects,2"* and contact tympanic ther­ mometry cannot be used in the sports arena. the fact that tac may underestimate body core tem­ perature would not prevent its use, as a field ther­ mometer, if the relationship between tac and blood temperature was fixed, in sports participants, and uncontaminated by other variables. however, that is not the case. li particular, auditory canal temperatures are influenced by head skin temperature/'13ls 17 heat sports medicine october 1998 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) loss from die human head constitutes a major compo­ nent of total heat loss during exercise, particularly when there is additional convective cooling in sweating subjects;3'19 fanning the face of hyperthermic subjects reduces tiv.s im the effect of head skin temperature on tac arises not primarily from the pinna, but from tlie scalp directly above and behind the ear.13 hockey play­ ers, unlike tlie other sports participants in our study, exercised outdoors in windy conditions. tlie air move­ ment, arising from ambient wind and tlie players’ motion, would have induced convective and evapora­ tive heat loss from scalps which may be the reason that post-exercise tac was lower than tac at rest. in our view, therefore, auditory canal th e r m o m e t r y is unlikely to offer an improvement on oral thermome­ try for the screening of sports participants for hyper­ thermia or hypothermia, and we reaffirm that oral thermometry provides an inconsistent underestimate o f blood temperature after sport. it remains remotely possible that tac does have some recognizable rela­ tionship with blood temperature in sports participants; the public nature of our study prevented us measuring rectal temperature (trc). correlation of tlu. with trc in a variety of sports participants still needs to be done. in one recent study,24 there was poor agreement between measurements of tac and t n: in athletes with suspect­ ed exertion-induced heat exhaustion. tac on admission to the field medical centre was on average 1.2 "c lower than trc. in addition, statistical variability between the two measures o f body temperature was such that mea­ surements of' t .li: could not be used confidently to pre­ dict a rectal temperature greater than 38 ’c. the inves­ tigators concluded that the use of infrared tympanic membrane thermometry can result in misdiagnosis of heat exhaustion.9 therefore, it seems unlikely that there will be a recognizable relationship between tac and trc in sports participants. acknowledgements we thank candice downing, t anya bohm and carey eddy for assistance with the data collection. this work was supported by the foundation for research development. references 1. benzinger tii. on physical heat regulation and the sense o f temperature in man. proc nat a ca d sci usa 1959: 45: 645-659. 2. benzinger th, taylor gw. cranial measurements o f inter­ nal temperature in man. in: h ardy jd ed. temperature: its measurement and control in science and industry. new york: reinhokl publishing corp., 1963: 111-120. 3. brengelmann gl. dilemma o f body temperature measure­ ment. in: shiraki k , yousef m k eds. man in stressful environments. springfield: thomas, 19 87 : 5-22. 4. brinnel h, cabanac m. hyperthermia and human brain cooling. in: shiraki k . yousef m k eds. man in stressful environments. springfield: thomas, 1987: 87-97. 5. brinnel h , cabanac m. tympanic temperature is a core temperature in humans. j therm biol 1989: 14: 47-53. 6. chamberlain jm, terndrap te, alexander dt, silverstone f a , wolf klein g, o d onnell r, grandner j. determination of normal ear temperature with an infrared emission detec­ tion thermometer. a nn emerg med 19 95 : 2 5 :15 -2 0. 7. erickson r. oral temperature differences in relation to ther­ mometer and technique. ivurs r es 1 9 8 0 :2 9 : 157-164. 8. fraden j, lackey rp. estimation o f body sites tempera­ tures from tympanic measurements. clin pediatr 1 9 91 : 3 0 (suppl): 65-70. 9. h ansen r d , olds ts, richards d a , richards cr, leelarthaepin b. infrared thermometry in the diagnosis and treatment of heat exhaustion. int j sports med 1996: 17: 66-70. 10. kelly b, alexander d. effect o f otitis media on infrared tympanic thermometry. clin pediatr 1 9 91 : 3 0 (suppl.) :46 48. 11. kenney rd, fortenberry jd, surratt ss, ribbeck bm, thomas wj. evaluation o f an infrared tympanic membrane thermometer in pediatric patients. pediatrics 1990: 85 : 854-858. 12. mairaux p, sagot jc, candas v. oral temperature as an index o f core temperature during heat transients. eur j a p p l physiol 1983: 50 : 33 1-34 1. 13. marcus p. some effects o f cooling and heating areas o f the head and neck on body temperature measurement at the ear. aerospace med 1973: 44 : 39 7-40 2. 14. mcardle w d, katch fi, katch, vl. exercise physiology: energy, nutrition and human performance. 3rd edition, philadelphia: lea and febiger, 1991: 569. 15. mccaffrey tv, mccook r d . wurster r d . effect o f head skin temperature on tympanic and oral temperature in man. j a pp l physiol 1975: 3 9 : 114-118. 16. mitchell d, laburn hp. pathophysiology o f temperature regulation. physiologist 19 85 : 28 : 507-517. 1 1 ■ nadel er, horvath sm. comparison o f tympanic mem­ brane and deep body temperatures in man. life sci 1970: 9: 869-875. 18. nielsen b. natural cooling o f the brain during outdoor bicy­ cling? pflugers archives 1 9 88 : 4 1 1 : 45 6-46 1. 19. rasch w, samson p, cote j, cabanac m. heal loss from the human head during exercise. j appl physiol 1 9 91 : 71: 590 595. 20. shenep jl, adair jr, hughes wt, roberson pk, flynn pm, brodkey to. fullen gh, kennedy wt, oakes ll, marina nm. infrared, thermistor, and glass-mercury ther­ mometry for measurement o f body temperature in children with cancer. clin pediatr 1991: 3 0 (suppl.): 36-41. 21. strydom nb, wyndham ch, willianis cg, morrison jf, bredell g a g , joffe a . oral/rectal temperature differences during work and heat stress. j appl physiol 1965: 2 0 : 283 287. 22. terndrup te. a n appraisal o f temperature assessment by infrared emission detection tympanic thermometry. a nn emerg med 1992: 2 1 : 1483-1 492 . 23. terndrup te, allegra jr, k ealy j a a . comparison o f oral, rectal, and tympanic membrane-derived temperature changes after ingestion o f liquids and smoking. a m j emerg med 1 9 89 : 7: 150-154. 24. terndrup te, wong a . influence o f otitis media on the cor­ relation between rectal and auditory canal temperatures. a j d c 19 91 : 145: 75-78. ' □ 18 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) brief report: urinary catecholamine excretion during outdoor sport rockclimbing f marino phd, med bpe j booth msp sc, bed human movement studies unit, human performance laboratory charles sturt university, bathurst, nsw 2 7 9 5 australia abstract objectives: the purpose of this study was to examine the response of urinary excretion of catecholamines after a bout of outdoor sport rockclimbing. design, setting & subjects: this study was undertaken outdoors in the blue mountains in nsw, australia. seven elite rockclimbers were recruited for the study. each had previous experience with the climb route. the subjects were required to climb the route as fast as possible. heart rate (hr) and urinary excretion of catecholamines (epinephrine, epi; norepinephrine, ne) were measured pre-climb, immediately post-climb and 30 min post-climb. results & conclusions: the duration of the climb was ~7 min, 36 s. fir increased from 74 bpm (pre-climb) to 157 bpm during the climb. the rise in cate­ cholamine excretion was not significant compared to pre-climb samples at either of the sample times. it is concluded that training induced adaptations to this type of exercise coupled with the methodological con­ straints of the study are responsible for the non-signif­ icant increases in catecholamine excretion. introduction rockclimbing has increased in popularity in recent years. the follow-on has seen improvement in climb­ ing standards and competitions.1 however, unlike other popular sports t here are not much scientific data on rockclimbers and rockclimbing with most ol the available data related to typical climbing injuries.13 more recently, however, anthropometric data has become available.45 data on the physiological respons­ es and requirements of rockclimbing is somewhat scarce with inferences mainly being drawn from other related activities such as mountaineering and gymnas­ tics. however, sport rockclimbing is unlike the more studied sports with the exercise itself characterised by isometric muscle contractions and gymnastic type movements. furthermore, the sport may be considered ‘high risk’ which adds a stressful component to the physiological demands. correspondence: frank marino human movement studies unit human performance laboratory charles sturt university, bathurst, nsw 2795 australia tel: 61 + 2 + 63 384268 fax: 61 + 2 + 63 384065 email: frnarino@csu.edu.au blood and urine catecholamine concentrations have been typically used as an index of sympathetic activity and have been shown to differ between trained and untrained subjects.0 because rockclimbing activity relies heavily on static muscular contractions, increased sympathetic activity would be expected.7 therefore, it would be of significant interest to evalu­ ate the sympathetic drive elicited by a bout of outdoor rockclimbing. furthermore, the common cate­ cholamine response exhibited after similar or ‘high risk’ type activity such as rockclimbing is an increased epinephrine (epi) and norepinephrine (ne) response.8 for example, the urinary levels of epi and ne in para­ chutist trainees were found to increase for initial jumps and then subsequently decline over the training period for both pre-jump and post-jmnp values. this decrease hi epi and ne is indicative of a reduced adrenomedulary discharge as a consequence of famil­ iarisation to a previously stressful event. this type of physiological response has yet to be studied in trained sport rockclimbers. therefore, the aim of t li i s study was to examine the response of uri­ nary7 excretion of catecholamines after a bout of out­ door sport rockclimbing. m e t h o d s subjects: seven competitive rockclimbers (6 male, 1 female) were recruited for this study. the mean climb­ ing experience of the group was 8.9 ± 1.2 years with the most difficult outdoor ascent made without pre­ view or fall ranging from 6b 7a (uk grading system). all subjects were in good health as determined by a medical and health questionnaire. the study was approved by the university ethics in human research committee. the mean (± se) age, height, mass and sum of nine skinfolds were 25 ± 1 years, 175.7 ± 2.7 cm, 62.6 ± 3.3 kg, and 61.3 + 4.2 mm, respectively. climbing protocol: the climb was graded 5c and was conducted on a rockface in the blue mountains of new south wales, australia. all subjects had previous expe­ rience witli the climb on at least three other occasions. the length of the climb was 24.4 m and overhanging by = 4m throughout at an elevation o f 890 m. on one occa­ sion approximately 5 7 d prior to the climb a resting sample of urine was collected after subjects abstained from alcohol, caffeine ingestion and vigorous exercise for a minimum period of 24 h. the reasons for this were that the route to the climb was lengthy with sub­ jects required to walk for approximately 20 mill and in some instances the terrain physically demanding. flence, a pre-climb sample at die climb site would have influenced the outcome of the urine concentration o f catecholamines. once arrived at the climb site sub­ jects rested for at least 30 min before micturition. at sports medicine october 1998 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:frnarino@csu.edu.au the climb site the subjects were briefed as to the con­ ditions of the climbing protocol and prepared for climbing with a waist harness secured to a 10 mm dynamic rope fed through a ring bolt at tlie top of the rockface and to a belayer at the start of the climb. the briefing and preparation was approximately 20 30 min duration. subjects were required to climb the route as quickly as possible. on completion of the climb each subject was lowered to tlie ground and given a specimen bottle for collection of urine. the specimen bottle and urine sample were returned with­ in ( 5 min of completing the climb. on returning the urine sample the subjects were given a bottle contain­ ing 350 nil of water to ingest over a period of 15-20 min before giving another urine sample 30 min post climb. during the climb heart rate (hr) was monitored con­ tinuously with a sports tester (polar-electro, oy., finland). catecholamine determination: the urine samples were collected in specimen bottles and acidified to ph 2-3 with 15 ml of hydrochloric acid. immediately after collection the samples were stored on ice and subse­ quently frozen (-20‘c) until analysis. all samples were analysed in the same run to avoid inter-assay variation. the method of determination was by high performance liquid chromatography according to pillai.9 this method requires less urine (0.5 ml vs. 4 ml) and is quicker with adjustment of ph facilitated by a visual indicator. statistics: the data were analysed by aimova with repeated measures on time for hr and for urinary' cat­ echolamine concentrations (pre-climb ae post-climb se 30 min post-climb). when significant main effects were found tukey’s hsd post-hoc procedure was employed to locate the source o f significant difference. significance was accepted when p < 0.05. all values are expressed as means ± se. results climb duration and hr: tlie time taken for the climb was 7 min, 36 s (range 6 min 28 s 9 min 54 s). pre­ climb hr was 74 ± 5 bpm and increased to 145 ± 10 bpm (p < 0.05) and 157 ± 8 bpm after 1 and 5 min of climbing, respectively. iir peaked at 83 bpm above resting values. urinary catecholamine concentrations: tlie results of the catecholamine analysis are shown in figure 1. resting urinary concentrations of epi, ne and total catecholamines (cax0x) were 89.1 ± 20.1, 315.5 ± 78.8, 404.6 ± 98.3 nmoles.l', respectively. the rise in uri­ nary excretion of epi was not significant (p = 0.26) with levels reaching 118.5 ± 21.0 nmoles.l 1 and 180.5 ± 73.3 nmoles.l-1 immediately post-climb and 30 min post-climb, respectively. a similar non significant (p = 0.35) finding for tlie urinary excretion of ne was observed with levels reaching 304.6 ± 42.6 nmoles.l'1 immediately post-climb and rising to 731.4 ± 430.3 nmoles.l1 30 min post-climb. catot were not signifi­ cantly changed (p = 0.34) with values rising to 423.2 ± 60.1 nmoles.l"1 immediately post-climb and 911.8 ± 501.8 nmoles.l1 (range 195 4407 nmoles.l1) 30 min post-climb. cholamine excretion in trained sport rockclimbers during outdoor climbing. sample times are at pre-climb (1), immediately post-climb (2 ) and, 30 min post-climb (3). discussion this is the first study to examine tlie sympathetic ner­ vous system response in elite rockclimbers while climbing in tlie field. tlie levels of ne and epi excre­ tion observed in tlie pre-climb urine sample were with­ in the normal range (epi < 101 nmoles.l'1 ; ne < 701 nmoles.l1) as reported by tlie pathology laboratory' (barratt & smith, pathology, orange, nsw, australia). furthermore, ne concentration was ( 3.5 times that of epi and is considered normal.1" therefore, it is rea­ sonable to assume that tlie sampling and determina­ tion procedures were satisfactory for this type of field experiment. although urinary excretion of cate­ cholamines is not ordinarily regarded as an accurate measure of sympathoadrenal activity," tlie geographi­ cal setting and isolation of the investigation prevented tlie use of serial venous blood sampling. even though there was a tendency' for cat0t con­ centration to increase after the climb, tlie post-climb sample was not statistically' different compared to the pre-climb sample. tlie large se associated with tlie 30 min post-climb cattot is most likely' related to the large range of values recorded for both epi and ne and the fact that one subject in particular responded with very' high values for both amines. however, a very dis­ tinct pattern did emerge from the immediate post­ climb sample to the 30 min post-climb sample for both amines. epi excretion showed a more linear rise at all three sample times, whereas ne only showed an increase for the 30 min post-climb sample. this increase in post-climb ne can be partly explained by the delayed sympathetic spill from neuronal sites into the circulation and eventually into the tuine.8 however, given that there was no statistical signifi­ cance between samples at the various measurement times, it is difficult to speculate as to the role that the sympathetic nervous system may have played during tlie climb. nonetheless, several points can be raised with respect to the present findings. for instance, pre­ vious work has shown increases in plasma cate­ cholamine concentration when isometric handgrip exercise is performed at levels above 20% of maximum voluntary contraction (mvc).7 although mvc was not measured in this study, it would be reasonable to assume that subjects performed isometric exercise 20 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) above 20% mvc given that they were required to lift their own body weight and that the climb was over­ hanging by = 4 m thereby increasing the negative effects of gravity. furthermore, recent evidence indi­ cates that trained climbers are able to generate signif­ icantly higher forces on grip strength tests compared to either recreational or non-climbers.1' although, rockclimbing is characterised by inter­ mittent isometric muscle contractions, some dynamic muscle work is also performed. ail elevated hr of at least 30 bpm during short-term dynamic exercise is required to stimulate a rise in plasma catecholamine concentration.13 in this study, hr increased by = 83 bpm above the pre-climb value. hence, a rise in cate­ cholamine concentration would be expected. however, even at high work rates epi levels are not always ele­ vated compared to ne.14 this might partly account for the non-significant increase in urinary concentrations of catecholamines observed hi this study. exercise intensity is also a determinant of sympa­ thetic st imulation. previous work suggests that at least a 30% increase in v02 must be elicited for an increase in catecholamine concentration.11 a recent investiga­ tion has shown that rockclimbers use less than 50% of v02lllax during a standard indoor climb.15 however, work in our laboratory indicates that rockclimbers use up to 75% o fv 0 2ma, ( = 44 ml.kg.miir1) if the v02max is expressed as a function of graded climbing (unpub­ lished observations). these data indicate that rock climbing can elicit an exercise intensity above that which is normally required to stimulate sympathetic activity. moreover, a given vog elicited by dynamic arm work increases catecholamine concentrations to a higher level than if the same v02 is elicited by leg work.11517 although the present findings are not statisti­ cally significant, the pattern of urinary catecholamine excretion seem to support previous findings. there are at least three possible explanations why the rise in urinary catecholamine concentrations failed to reach statistical significance. first, plasma concen­ trations of catecholamines have been shown to be attenuated during acute exercise following train jhg_n.i8.i9 thjs sympathetic adaptation has also been observed in subjects with physically trained arms whilst performing handgrip exercise.2021 tliis might partly explain the blunt catecholamine response in this study. second, the results support the notion that trained individuals do not necessarily perceive the activity as ‘high risk’ as less trained individuals who exhibit signs of subjective fear.8 also, the methodolog­ ical features of the study may have contributed to a reduced sympathetic response than would have other­ wise been expected. for instance, the climbers were secured to a top rope rather than lead climb and all climbers had previous experience on the route, all of which may have attenuated the subjective fear. in summary, elite sport rockclimbers do not exhib­ it significant]}7 elevated catecholamine concentrations as measured in urine after a bout ol moderatlcv diffi­ cult outdoor climbing. this may be due to training induced adaptations to the exercise and the method­ ological constraints of the investigation. it is suggested that further field work be undertaken to confirm these findings so that physiological responses to such a high­ ly skilled activity be quantified and used in order to provide a practical approach to training and prepara­ tion for competition and that the stresses related to this activity be understood. references 1. bollen sr. soft, tissue injury in extreme rockclimbers. br j sp med 1988; 22 : 145-147. 2. bollen sr, gunson ck. hand injuries in competition climbers. b r j sp med 1990; 24 : 16-18. 3. iloltzhausen lm, & noakes td. elbow, forearm, wrist, and hand injuries among sport rockclimbers. clin j sport med 1996; 6: 196-203. 4. watts pb, martin dt, & durtschi s. anthropometric pro­ files oj elite male and female competitive sport rock climbers. j sports sc 1993; 11:113-117. 5. iloltzhausen lm, schwellnus mp, & noakes td. anthropometric and muscle strength measurements o f com­ petitive south african sport rockclimbers. sth a j j sports med 1996; 4:13-18. 6. mazzeo rs. catecholamine responses to acute and chronic exercise. med sci sports exerc 1991: 7: 839-845. 7. seals dr, chase pb, taylor ja . autonomic mediation o f the pressor response to isometric exercise in humans. j appl physiol 1988; 64: 2 1 90 -2 196 . 8. hansen jr, stoa i<f, blix as, & ursin ii. urinary levels o f epinephrine and norepinephrine in parachutist trainees. in: ursin h, badde e, & levine s eds. pysychobiology o f stress: a study o f coping men. neiv york: academic press, 1978, 63-74. 9. pillai dn. inexpensive alternative to kit methods for extrac­ tion o f urinary catecholamines. clin chem, 1987: 3 3 : 11. 10. karki nt. the urinary excretion o f noreadrenaline and adrenaline in different age groups, its diurnal variations and the effect o f muscular work on it. a cta physiol scand 19 56 ; 3 9 : 13 2 (suppl) . 11. galbo, h. hormonal and metabolic adaptation to exercise. thieme-stratton inc, 19 83 : 7-8. 12. grant s, h yn e s v, whittaker a , a itch ison t. anthropometric, strength, endurance and flexibility charac tersitics o f elite and recreational climbers. j sports sc 1996; 14: 301-309. 13. christensen nj, brandshorg o. the relationship between plasma catecholamine concentration and pulse rate during exercise and standing. eur j clin invest 1973; 3 : 29 9-30 6. 14. galbo ii, h olst jj, christensen nj. glucagon and plasma catecholamine responses to graded and prolonged exercise in man. j appl physiol 1 9 /5 : 38 : i0-7 6. 15. billat v, palleja p, charlaix t, rizzardo p. & janel n. energy specificity o f rockclimbing and aerobic capacity in competitive sport rock climbers. j sports med phys fit 1995; 3 5 : 20-24. 16. blom qvist cg, lewis sf, taylor wf, graham rm. similarity o f the hemodynamic responses to static and dynamic exercise o f small muscle groups. circ res 1981; 48, suppl 1, 87-92. 17. davies, ctm, few j, foster k g , sargeant aj. plasma cat­ echolamine concentration during dynamic exercise involv ina different muscle groups. eur j a ppl physiol 1974; 32 : 195-206. 18. peronnet f, cleroux j, perrault ii, cousineau d , de champlain j, nadeau r. plasma norepinephrine response to exercise before and after training in humans. j appl physiol 1 9 81 ; 51 : 812-81 5. 19. winder ww, hickson rc. ilagberg jm, ehsani a a , mclane j a . training-induced changes in hormonal and metabolic responses to suhmaximal exercise. j appl physiol 1979; 4 6 : 766-771. 20. sinoway l, r ea r, smith m, mark a . physical training induces desensitization of the muscle metaboreflex. circulation 1989: 8 0 suppl: i i 289. 21. somers vk, leo k c , green mp, m a rk a l . forearm training alters the sympathetic nerve response to isometric hand­ grip. circulation 19 88 ; 78 suppl: i i 177. □ sports medicine october 1998 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) position statement position statement: code of ethics in sports medicine international sports medicine federation (fims) the following statement was approved by the fims executive committee on 33 september 1997 1. medical ethics in general tlie same ethical principles that apply to the practice of medicine shall apply to sports medicine. the main duties of a physician include: • always make tlie health o f tlie athlete a priority. • never do harm. • never impose your authority in a way that impinges on the individual right of the athlete to make his/her own decisions.1 2. ethics in sports medicine physicians who care for athletes of all ages have an ethical obligation to understand the specific physical, mental and emotional demands of physical activity, exercise and sports training. a different relationship exists between sports med­ icine practitioners, their employers, official sports organization, professional colleagues and tlie athletes.2 in sports medicine there is also a link between the pathologic concern and specific recreational and pro­ fessional activity. an athletic injury has a direct and immediate impact on the participation in this activity that may have psychological and financial implica­ tions. the most obvious difference between sports medicine and other aspects of medicine is that tlie athletes treat ed are generally healthy. ethics in sports medicine should also be distin­ guished from law as it relates to sport. one refers to morality the other to a set of enforceable social rules.2 although it is desirable that the law be grounded in moral principles and that matters of moral importance should be given legal backing in many instances, not everything that is illegal is immoral and similarly not every immoral behaviour is against the law. thus when speaking of ethics in sports medicine, one is not c o n ­ cerned with etiquette or law, but with basic morality. 3. special ethical issues in sports medicine the physician’s duty to the athlete must be his/her first concern and contractual and other responsibilities are of secondary importance. a medical decision must be taken honestly and conscientiously. a basic ethical principle in health care is that of respect for autonomy. an essential component o f auton­ omy is knowledge. failure to obtain informed consent is to undermine the atlilete's autonomy. similarly, fail­ ure to give them necessary information violates the right o f tlie athlete to make autonomous choices. truthfulness is important in health care ethics. tlie overriding ethical concern is to provide information to tlie best of one’s ability that is necessary for the patient to decide and act autonomously. the highest respect wall ahvays be maintained for human life and well-being. a mere motive of profit shall never be permitted to be an influence in conduct­ ing sports medicine practice or functions.3 4. the athlete-phvsician relationship the physician shall not allow' consideration of religion nationality, race, party politics or social standing to intervene between his/her duty and tlie athlete. the basis of the relationship between the physician and tlie athlete should be that of absolute confidence and mutual respect. tlie athlete can expect a physician to exercise professional skill at all times. advice given and action taken should ahvays be in the athlete's best interest. the atlilete’s right to privacy must be protected. the regulations regarding medical records in health care and medicine shall also be applied in the field of sports medicine. the sports medicine physician should maintain a complete and accurate record of the patient. in view' of the strong public and media interest in the health of athletes, the physician should decide with the athlete w'hat information can be released for public distribution.1 when serving as a team physician, the sports med­ icine physician assumes the responsibility to athletes as well as team administrators and coaches. it is essential that each athlete is informed of that respon­ sibility and authorizes disclosure of otherwise confi­ dential medical information, but solely to the specific responsible persons and for tlie expressed purpose of determining the fitness of tlie athlete for participa­ tion.4 the sports medicine physician will inform the ath­ lete about the treatment, the use of medication and tlie possible consequences in an understandable way and proceed to request his or her permission for tlie treatment. the team physician will explain to tlie individual athlete that he or she is free to consult another physi­ cian. 5. training and competition sports medicine physicians should oppose training and practices and competition rules as they m a y jeop­ ardize the health of the athlete. in general, the physi­ cian shall obtain knowledge of the specific and mental demands made of athletes w'hen they participate in sport activities. relevant aspects hi this respect include expertise, effectiveness and efficiency, and safety.5 if the athletes concerned are children or growing individuals, the physician must take into consideration tlie special risks that the sport in questions may rep­ resent to persons w'ho have not yet reached physical or psychological maturity. when tlie sports participant is a growing individual, the sports physician must ensure that the training and competition are appropriate for the state of growth and development.4 tlie physician shall contribute to the spreading of information or the special conditions that pertain to young people training and competing. it is vital that this information also reaches tlie young athletes, parents, guardians, and trainers.1 22 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 6 . e d u ca tio n sports medicine physicians should participate in con­ tinuing education courses to improve and maintain the knowledge and skills that will allow them to provide optimal advice and care to their patient athletes.0 knowledge should be shared with colleagues in the field. 7. health promotion sports medicine physicians are obligated to educate people of all ages about the health benefits of physical activity and exercise. 8. injuries and athletes it is the responsibility of the sports medicine physician to determine whether tlie injured athletes should con­ tinue training or participate in competition. the out­ come of the competition or tlie coaches should not influence the decision, but solely the possible risks and consequences to tlie health o f the athlete. if the physician considers that a certain sport entails major risks he should try to eliminate the risk by exerting pressure on the athletes as well as on the relevant decision makers. injury prevention should receive the highest priori­ ty. 9. therapeutic exercise when supported by scientific research, a detailed exer­ cise prescription should be part of the therapeutic plan for an athlete recovering from injury or disease. 10. relationship with other professionals tlie sports medicine physician should work in collabo­ ration with professionals of other disciplines. the sports medicine physician should cooperate with phys­ ical therapists, podiatrists, psychologists, sport scien­ tists including biochemist, biomechanics, physiolo­ gists, and others. tlie sports medicine physician has the final responsibility for the health and appropriate medical specialists in the prevention, treatment and rehabilitation of disease and injury. tlie concept of interdisciplinary team work is fundamental to the practice of sports medicine. a sports medicine physician should refrain from publ icly criticizing fellow professionals who are involved in the treatment of athletes. a sports medicine physician should behave in rela­ tion to his colleagues and coworkers as he would like them to behave towards him. when a sports medicine physician recognizes that the athlete's problems are beyond his level of exper­ tise, it beholds him to advise tlie athlete of other per­ sons with tlie necessary expertise and refer the athlete to such appropriate persons for assistance. 11. relation to officials, clubs, etc. at a sport venue, it is the responsibility of tlie sports medicine physician to determine wrhen an injured ath­ lete can participate in or return to an event or game. tlie physician should not delegate this decision. in all cases, priority must be given to the athlete's health and safety. the outcome of the competition must never influence such decisions. to enable the sports medicine physician to under­ take this ethical obligation the sports medicine physi­ cian must insist on professional autonomy and respon­ sibility for all medical decisions concerning the health, safety and legitimate interest o f the athlete. no third party should influence these decisions.3 no information about an athlete may be given to a third party without the consent of the athlete. 12. doping (see fims position statement) tlie sports medicine physician should oppose and in practice refrain from using methods to improve perfor­ mance artificial!j7 such as those prohibited by the ioc.4 the physicians have forcefully opposed the use of methods that are not in accordance with medical ethics or scientifically proven experience. thus, it is contrary to medical ethics to condone doping in any form. neither may the physician in anyway mask pain in order to enable the athlete's return to practicing the sport if there is any risk of aggravating the injury.1 13. research research should be conducted following the ethical principles accepted for research in animals and human subjects. research should never be conducted in a manner which may injure athletes or jeopardize their athletic performance. references 1. code o f ethics. swedish society o f sports medicine. 2. h odge kp. character building in sport: fact or fiction? new zealand journal o f sports medicine 1 7 ( 2 ) :23-25, 1989. 3. code o f ethics. sports medicine australia. 4. principles and ethical guidelines o f health care for sports medicine. international olympic committee. 5. code o f ethics. the netherlands association o f sports medicine. 6. code o f ethics. the american college o f sports medicine. this statement was prepared by: per a.f. h. renstrom, md, phd (chair); walter r. frontera, md, phd; anthonv j. parker, phd; and john b.m. wesseling, md. [note: this statement may be reproduced and distrib­ uted with the sole requirement that it be identified clearly as a statement of the federation internationale de medecine sportive.] □ sports medicine october 1998 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasma news welcome to the firs t of a regular feature in the new journal. as one of the changes to the journal, these pages will contain local and international news, o th e r features, and details of congresses. privileged healthcare professionals who received froben's new sportsmed quarterly would have been intrigued to discover the existence of a new sports medicine o rg a n isa tio n , sasmo. this "organisation" in the end turned o u t to be the ''association” in mis-spelt guise. acronyms are well loved in sa. but ju s t w hat are sagca, nocsa, nsc, ioc, anoca, sisa, ssisa, acsm, etc? we'll investigate some o f these in the months to come. w h at is sisa? the sports inform ation and science agency (sisa) is an agency which at present is fully funded by the department of sport and recreation. according to the secretariat mr. galant, directors are made up from equal representa­ tion fro m the department, the national sports council and the national olympic committee. sasma members may remember th e ir involvem ent in funding part of the sasma biennial general meeting in sun city last year. they have also collaborated w ith sasma in bringing out the position statem ent on aids in sport. the aim of the agency is the rendering o f support services to sportspeople in the medical, scientific and physiotherapy fields, and also in the areas o f inform ation and technology. they see sasma as being an im portant client o f sisa in advising and rendering quality sports medicine. sisa plan to have the various aspects of sports medicine and science accredited, and th a t effectively means activities in all the fields in which sasma members are currently involved. at present they have accredited nineteen institutions in south africa (technicons, universities, and the sports science institute), and the plan is to accredit the clinicians in the futu re . the sports science and medicine listing book th a t sasma members received recently is the firs t stage in this process, it has also been sent to the 120 sports federations as a source o f inform ation (w ith o u t specific guarantee of quality!), to enable them to make th e ir own decisions in health care, as the accredited infrastructure is, n o t yet in place. c om m o nw ealth games 1998 (and sacga) the queen's baton passed through sa on its firs t visit to this country, as part of its relay run to malaysia. the south african com m onw ealth games association (sacga) is the body responsible fo r organising this event every fo u r years. supporting the athletes in one of the world's major sporting events is a medical and scientific team. the stated aims are to ensure th a t the physical well-being o f the athletes are carefully m onitored, and timeous intervention in stitute d when necessary, and also to identify, encourage and prom ote participation o f sports physicians, phys­ iotherapists and sports scientists from the so-called disadvantaged com m unities in the support structure. the team provides support in three fields around the country. scientific: ms. noo scales & mr. justin du rant (cape town), prof. geoff rodgers (johannesburg), dr. yoga coopoo & prof. maurice mars (durban), drs. ian cook, jones cilliers & jacques rossouw (pretoria). medical: profs wayne diesel & martin schwellnus (cape town), drs. ponky firer & demitri constantinou (johannesburg), dr. mike marshall (durban), dr. philda de jager (pretoria). physiotherapy: prof. wayne diesel (cape town), ms. tanya bell (johannesburg), ms. joyce m orton (durban), ms. jaqui mccord (pretoria). mr. khalid galant coordinates the scientific evaluation and m o n itoring of athletes throu g h the high performance programm e of sisa. the ubiquitous dr ismail jakoet is the appointed chief medical officer, and o ft-quoted prof. tim noakes, the medical advisor. the medical teams continue to have a strong, albeit dubious influence on the physical appearance of our nation­ al teams. one o f the major inputs in the field of physiotherapy has been the appearance o f tattoos on the hides of the springbok rugby team. this was taken fu rth e r at the commonwealth games where the medical team won distinction by being fined fo r n o t dressing properly. apart fro m these sartorial slipups, tours such as the commonwealth games have served to expose various sporting codes to cu rre n t views and good sports medicine practices. many coaching or management practices may seem outdated or inappropriate to the medical team. there in certainly a perceived need to educate coaches and managers, b u t perhaps the to u r itself is not the best place to start doing this. these sporting disciplines and personnel may benefit fro m being more involved in sasma activities. o ther events remember th a t our own sasma congress has moved from its usual march slot to september 1999, to coincide w ith the all africa games, and will be held in johannesburg, rather than cape town. this allows the conference to receive sponsorship from anoca and nocsa. current sasma president prof. wayne derman says th a t the conference will be an "african renaissance" project at the request of the african renaissance committee of the deputy president (is th a t arcodp?) incoming sasma president dr philda de jager represents a departure fro m recent history and illustrates the benefit of having a rotating presidency. being the firs t female president, and the firs t inland president fo r some time, we hope she will be able to keep her head above w ater a little b e tte r than she has done in her sporting life ... (her women's underwater hockey team returned as world champions fro m th e ir to u r to the us). □ 24 sports medicine october 1998 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) inflam m atory pain relief and m obility in any body s language. r-\ *v\ 1 c *4 he *y\ h 1 mg tablet. each tablet p .q t^ a ^ ^ 'fn ^ ^ e lo x ic a m . reg. no. 29/3.1/421. .. :^:.t^^^uppost!cii;i.qs<-6a6h:s'^p'^sitory contains '$5 mg meloxtcam. reg no. 29/3.1/425|£\ boehringer ^ylogeiheim fioehnngsf in g a m e im ^ y ) u tt, ftsg,‘| ^ i ^ d 8 6 19/07. 404 main avenue, f e rn d a l| randburg 2194. tel 685-1075. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) • effective locally acting therapy against pain and inflammation.' • well tolerated.' • convenient non-slicky, non-greasy formulation with no residue. • cooling sensalion on skin, u/ilh a pleasant menlhol aroma.' tm l a t oboots h ea lth c a r e 40 electron avenue isando 1600 pst| lions/vl,,. lot 11 perk lie ontams 4 0 mg flurbiprofen beg do flv y l'o zm beleience 1 gikhu* i suqauam v l\higoni id, votoh) su/uki k. l<xcil mrhon ironwutaneom flurbiprofen (flurbiprofen lap in the rreoinienl ol <kuie mirtculovkelpiol condllioitt qevleiv of turopeon and ioponew» experience we've got acute pain and inflammation covered. urfoiprolen 4 0 mcj tra1195g041r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) south afric an jou rn al of sports medicine sportgeneeskunde jo u r n a l of t h e s.a. sports m ed icin e association t y d s k r if van die s.a. sportgeneeskunde-vereniging is s n 1015/5163 vol 5/no 3 august 1990 price r5.00 + gst failure to com plete a long distance sea swim ❖ l ow er limb compartment syndrom es ❖ protein in the diet r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nothin; will give yoj r h e u m a t o l o g y x..-vvw freedom to walk, jump, run and work s r i o oĵimplehegimenimplewe9imefi r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) south afr ic an jo u r n a l of sports medicine sportgeneeskunde jo u r n a l of t h e s.a. sports m ed ic in e association t y d s k r if van die s.a. sportgeneeskunde-vereniging v o l u m e 5 n u m b e r 3 a u g u s t 1990 editor in chief: d r c noble m b b c h, f c s fs a j a ssociate editors: p roft n oakes. m b c hb, m d dr d awievan veldenm b c hb (siellj m prax med l pretoria j advisory board: m e d ic in e : d r i cohen m b c hb . d .o bsi. r c o g o r t h o p a e d i c tr a u m a io lo g y : dr p firer b s c (eng). m b b ch (w its/. ,\ i m ed (oriho) ( wits) brig e hugo m b c h b , m m ed (c hin o r i h o p a e d ic s : drjc. usdin m b b c h , f r c s (edin) c a r d io lo g y : col d p m y burgh s m m b chb f a c c p h y s ic a l e d u c a tio n : profhannes botha d p hil (phys ed) g y n a e c o lo g y : d r j ack a dno m b b c h ( was/ .m d (med), d ip o & g (w u s j contents editorial comment ethical considerations in sports medicine ............ 3 epidemiology a n epidem iological study o f failure to com plete a long-distance sea swim ........................ 7 sports injuries low er limb compartment syndromes ................ 10 nutrition protein in the diet ..................................................... 12 physiotherapy update physiotherapy and the sprained ankle o f the sportsman ............................................................. 16 soccer soccer-w arm ing up and stretching sasma update fims world congress o f sports medicine report on the saassper/sasm a congress .. 22 p u b l i s h e d by t h e s o u t h a f r i c a n s p o r t s m e d i c i n e p iu lu r /; m u m s y o f p h o t o fi l d im a g e h d r k a s s o c i a t i o n h a t f i e l d f o r u .v t w e s t 1067 a r c a d ia s t r e e t h a t f i e l d p r e t o r i a . 00s3 t h e jo u rn a l o f th e sa s p o n s m e d ic in e a s s o c ia tio n is p u b lis h e d b y m e d p h a r m p u b lic a tio n s , 3 rd f lo o r n o o d h u lp lig a c e n tr e . 2 04b h f v e rw o e rd d r iv e . r a n d b u r g 2iv 4. tel: ( 0 1 1) 787 -4 9 8 1 /9 . t h e v ie w s e x p r e s s e d in ih is p u b lic a tio n a r e th o s e o f th e a u t h o r s a n d n o l n e c e s s a r ilv th o s e o f th e p u b lish e rs . p n n i f d b v t h i n . i u l w u n c w p r i m i n p j n d p u b lis h i n g c o m p a n v ( p i y ) l t d s p o r t g e n e e s k u n d e vo l 5. n r 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r s ten0xica.-n the first i.v. and i.m. 20mg once daily parenteral administration feh r ,-.•'sell ior ta ns r':ec!.on 'jilcotil 20 mg ■ *oche *■ 1 i(r ' rt*c c » *.*. w. l *< z ^ iix z s s b s r ' tr 'iv s : : * sto#ebe!cw25 r k e e p o u t o f ^^ofchilop^ 1.1s 01 composition in d ic a to r* contra-,ndicatons. s.de eitects aosaoe and drecauimns . on request from roche products ,p,yl l td , p o b o , 4589. j j l n e e s t o o z n es 2 2 ,0 [s3] reg. nos. vials: v/3. 1/238; h/34/128 tilcotil = trademark once tilcotil tenoxicam 20 mg nonsteroidal anri-inflam m atory d ru g rapid anti­ inflammatory & analgesic action for the treatment of sports injuries * r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) gpltorial ethical considerations in sports medicine t h ere is a grow ing m u lti-d iscip lin ary interest in sports m edicine in south africa m ainly d u e to the following reasons: • it gives an o p p o rtu n ity to certain professional people to practice m edicine. in this g ro u p are those w hose m ain in terest is in the treatm en t an d rehabilitatio n of spo rts injuries. • to apply m edical know ledge to th e benefit o f s p o r t. f o r these people the challenge and interest is to use anatom y, physiology, biochem istry, etc. to develop and im prove train in g m eth o d s so that ultim ately p e r­ form ance can be im p ro v e d . • f o r the c o n trib u tio n sp o rt and exercise can m ake to m edicine. t h e in terest o f these people is to ap p ly the various aspects o f sp o rt and exercise physical train in g , p a r­ ticip atio n , d iscipline to help in m edical pro b lem s w h eth er as p rev en tio n , tre a tm e n t or rehabilitation. t h is has resulted in a w ide range o f people becom ing interested in th e d iscipline and practice o f sports m edicine. u nfortunately, d u e to the diversion o f interests and grow ing body o f know ledge and expertise, it will never be possible to register a single m edical discipline such as a sports m edicine specialist. t h e em phasis should ra th e r be on teaching applied sports m edicine to existing professionals in their respec­ tive fields to eq u ip th em b e tte r to m anage m edical p ro b ­ lems relating to sport and exercise. in this respect it will be possible to train a p rim ary c are physician for general, p rim ary care of sp o rtsm e n , to give a p h y siotherapist a h igher degree in sports physiotherapy, o r to increase the know ledge o f an o rth o p ed ic surgeon in the field of sports traum atology. t h e universities in south africa recog­ nised these n eeds, an d are beg in n in g to investigate the possibility to offer various post g rad u ate courses in sports m edicine. as w ith any new b ran ch in m ed icin e, the b o u n d aries of sports m edicine has not b een , an d cannot be accurately defined. m edical practitio n ers and o th er professionals obtaining a h ig h er degree in spo rts m ed icin e, should for ethical reasons, confine th eir p ractices to th eir specific registered fields, be it in g eneral practice, p h y siothe­ rapy, o rth o p e d ic s, b iokinetics, e tc ., w ith a special interest in sp orts m edicine. p ractitio n ers m ay not ad v er­ tise them selves as “ s ports m edicine specialists”. professionals registered by the m edical and d ental c ouncil, m ay not advertise a p a rtic u la r p erso n , in stitu ­ tion, rem edy o r te ch n iq u e. t h e m ain p rin cip le u n d e rly ­ ing all the ethical rules concerned w ith this su b ject, is that a d octor o r o th er reg istered p e rso n , m ay not seek to at­ tract p atients in a m a n n e r th at w ould give him an ad v an ­ tage over his colleagues w ith sim ilar qualifications. by the registration o f m edical qualifications, the sa m edical and d en tal c ouncil also pro tect the public by laying dow n m in im u m sta n d a rd s in a circu m scrib ed c u r­ riculum . t h e lay p u b lic can th u s be reasonably assured that th e professional concerned has a stan d ard o f aca­ dem ic train in g to be able to practice in his specific field. d it is van die uiterste belang d at alle p ersone wat be trokke is by sp o rtg en eesk u n d e, sal op tree in belang van s p o r t s g e n e e s k u n d e vo l. 5 n r . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial sport en die sp o rtm an . d it sou du s oneties wees om sportgeneeskundige kennis te g eb ru ik tot nadeel van die sp o rtm an , soos byvoorbeeld die toediening van anabo liese steroiede aan gesonde sportlu i m et die uitsluitlike doel om sportprestasies te v erb eter so n d er inagnem ing van die g esondheidsim plikasies wat so ’n p ro sed u re mag inhou vir die b etro k k e persoon. d it kom ook neer op die onregm atige bevoordeling van die sp o rtm an bo sy oppo nente wat strydig is m et die reels van regverdigheid in sport. g eneeshere m oet hu lleself ook w eerhou om in hulle professionele hoed an ig h eid betro k k e te raak by adverten sie veldtogte om sekere aspekte van “g e so n d h e id ” te be v o rd er op so ’n w yse dat die betro k k e geneesheer hom self persoonlik onregm atiglik bevoordeel. m edici moet ook leer om flater w at die a ptekersprofessie gem aak het met die slagspreuk van “jou a ptek er weet die b este” w at die aptekersprofessie tot ’n sekere m ate ged isk red iteer h e t. d aarenteen m oet die b ep erk in g s wat op geneeshere ge plaas w ord m et b etrek k in g tot a d v erterin g , nie onredelik wees en te e n p ro d u k tie f inw erk op die p rak ty k van sport geneeskunde as sodanig nie en sal d aar m et nuw e oe ge kyk m oet w ord na die m ate van blootstelling wat mediese praktisyns mag k ry om hulle belangstellings en bekw aam hede op ’n etiese wyse bekend te stel. d it is allerwee be kend dat d aar w ereldw yd ’n verslapping is in die regula sies betreffende ad v erterin g d e u r professionele persone. die s p o rtgeneeskunde v ereniging stel dit hom ten doel om te waak oor die belange van sy lede en mee te help dat sportlui toegang het tot gespesialiseerde sp o rtg en eesk u n ­ dige d ienste tot voordeel van sport en g esondheid in die algem een. vir hierd ie doel is ’n etiese kom itee in die lewe geroep w at sekere etiese aspekte in die belangeveld van sportg en eesk u n d e ondersoek om so ook sy lede van raad en daad te bedien insake die k o rrek te o p tred e o n d er be paalde om standighede. professionele persone m oet ook versigtig wees om in die o p en b aar u itsp rak e te lew er oor die o p tred e van se­ kere kollegas indien dit die integriteit van die betrokke kollega o n d e r v erd en k in g kan brin g o f by im plikasie ’n an d er professionele liggaam diskrediteer. verskille van opinie in gen eesk u n d e sal d aar altyd w ees, m aar stand p u n te m oet op ’n professionele wyse besleg w ord in die geneeskundige veld is dit altyd gevaarlik om dogm aties te wees: jy mag m ore verk eerd bew ys word! s p o rtgeneeskunde bied interessante en verbeelding ryke uitdagings d it is ’n terrein w aarop d aar groot vor d ering gem aak is oor die afgelope jare. a lleenlik d e u r we dersydse e rk en n in g van professies en m u ltidissiplinere sam ew erking o n d e r b elan g h eb b en d es, kan die nuw e ho risonne verken w ord. dr. d awie van velden president: sa s p o rtg en eesk u n d e vereniging guideline for authors s c i e n t i f i c a r t ic l e s 1. t h e j o u r n a l o f the s outh a frican sports m edicine a ssociation p u b lish es original and review articles fro m all disciplines relevant to s p o rts m edicine. t h e jo u r n a l aims to c ater fo r th e diverse interests o f m em bers of the m edical and para-m edical professions and the s p o rtin g pub lic interested in scientific and m edical aspects o f sp o rt. 2. m aterial su b m itte d fo r p u b licatio n in the j s asm a is accepted on c o n d itio n th a t it has n o t been p u b lish ed elsew here. all nam ed a u th o rs m u st give signed c o n sen t to p u b lic a tio n , and th e js a s m a d o e s n o th o ld itself resp o n sib le fo rs ta te m e n ts m ade by c o n trib u to rs . 3. all s u b m itte d articles sh o u ld be of a p p ro p ria te scientific value and should have practical ap p licatio n in sp o rts m edicine. a rticles m ay be w ritte n in a frikaans o r e nglish. t he c o n trib u tio n s will be critically review ed by at least one a p p ro p ria te referee w h o is a specialist in the field o f the s u b m itte d m aterial. t his review wil be passed on a d o u b le -b lin d ap p ro ach (b o th a u th o r and referee will rem ain an o n y m o u s to each o th e r). t h e referee’s co m m en ts will be sent to the a u th o r to g e th e r w ith the evaluation o f o n e of the e d ito rs. a cceptance of the p ap er fo r p u b licatio n is based on o rig in a lity and q u a lity o f the w ork as well as on the clarity o f in te rp re ta tio n . t h e p ap ers will be p u b lish ed in the o rd e r of acceptance and n o t in the o rd e r of su b m issio n . t h e p u b lish e r reserves c o p y rig h t and re p ro d u c tio n rights o f all p u b lish e d m aterial, and such m aterial m ay n o t be re p ro d u c e d in any fo rm w ith o u t the p u b lis h e r’s w ritten p erm issio n . 4 -----------------------------------------------------------s p o r t s m e d i c i n e v o l 5 n o . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) guidelines for authors all m an u scrip ts to be directed to: t h e editor, jo u rn al o f s asm a , m ed p h arm p u b lications, 3rd f l o o r n o o d h u lp lig a c entre 204b h f verwoerd d rive r a n d b u rg 2194. preparation o f the manuscript m an u scrip ts should be ty p ew ritten , double-spaced on sheets o f uniform size, no larger th an 21 x 2 9 ,7 cm (d in a4) w ith a 3-cm m argin on th e left. all co n trib u tio n s are to be su b m itte d in d uplicate (one original w ith illustrations suitable for rep ro d u ctio n and two co m ­ plete copies in clu d in g copies o f figures and tables). o nly the original copy will be re tu rn e d to the authors(s) in case of revision or rejection. t h e cover page o f th e m an u scrip t should list the following inform ation: (i) concise b u t inform ative title (ii) k ey w ords (m axim um 58) (iii) a uthor(s) initials and nam e(s) (iv) n am e an d location o f institu tio n w here the investigations w ere c a r­ ried out (v) n am e and address o f the a u th o r to w hom co m m u n icatio n s co n cern ­ ing the co n trib u tio n should be d i­ rected (vi) a cknow ledgem ents o f research su p p o rt and research grants. t h e second page o f the m an u scrip t should in clude only the title o f the a r ­ ticle w ithout reference to th e a u th o r’s nam es or affiliations. t h e third page o f the m an u scrip t should give an abstract of th e scientific contents o f no m ore than 200 w ords and not exceeding one d o u ble-spaced type w ritten page. t h e text o f the m an u scrip t should be arranged as follows: an introduction d escribing the p u rp o se o f the w ork in relation to o th er w ork in the same field. material and methods: d escribe the selection of th e observational or ex p eri­ m ental subjects clearly. identify the m eth o d s, ap p aratu s and p ro ced u res in sufficient detail to allow o th er w orkers to rep ro d u ce the results. t h e results should be p resen ted conci­ sely. t h e statistical m eth o d used should be n am ed. a uth o rs m ust express un its, q u an tities, and form ulas according to the reco m m en d atio n s o f th e systeme in tern atio n al (si units). all m easu re­ m ents shou ld be given in m etric units. t h e d iscussion should em phasize the new and im p o rtan t aspects o f the study and the c onclusions that follow from them . t h e practical im plications o f the study shou ld be e m p h a siz e d . illustrations and tables figures consist o f all m aterial w hich cannot be set in type, such as p h o to ­ graphs and line draw ings. (tables are not in clu d ed in this classification and should not be su b m itte d as p h o to ­ graphs). in no circum stances should original x -r ay films be forw arded; glossy p rin ts m ust be su b m itted . tables and legends for illustrations should be typed on separate sheets and should be clearly identified. tables should carry r om an n u m erals, thus: i, i i, iii etc, and illustrations a rabic n u m erals, thus: 1 , 2 , 3 etc. tables should be self-explanatory and bear a short title. a bbreviations used should be explained in the legend or at the bottom o f th e table. illustratio n s should be labelled w ith the nam e o f the first a u th o r and the illustration n u m b e r on the top left-hand co rn er o f the back side. references references should be in serted in the text as su p erio r n u m b e rs, and should be listed at the end o f th e article in n u m e ri­ cal order. d o not list them alphabeti­ cally. it is the a u th o r’s respon sib ility to verify references from the original sources. r eferences should be set out in the v ancouver style, and only approved abbreviations o f journal titles should be used; consult the jan u ary issue o f index medicus (n o. 1, p art 1) for these d e ­ tails. n am es and initials o f a u th o rs should be given unless there are m ore than six, in w hich case th e first three nam es should be given followed by “et al”. f irst and last page n u m b e rs should be given e.g. 1. n oakes t d . h eart disease in m ara­ th o n ru n n e rs: a review . m ed sci sports e xerc 1987; 19: 194-198. book references should be set out as fol­ lows: 1. peterson l , r en stro m p. sports in ­ jures. t h e ir p rev en tio n and tre a t­ m ent, 1st ed. south africa: justa and co l td , 1986. 2. o ld rid g e nb: c om pliance w ith exercise program s. in: pollock m l , s chm idt d h , eds. h eart d is­ ease and r eh ab ilitatio n (ed 2). new y ork, jo h n w iley & sons, 1986: 629-646. “ the more practical articles, review articles, papers presented at congress etc, do not need to comply with such strict guidelines” practical articles t h e m ore practical articles, review a r­ ticles, papers p resented at congress etc, do n ot need to com ply w ith such strict g u id elin eslength l ength o f these c o n trib u tio n s should not how ever exceed 5-6 pages typed in double spacing. all co n trib u tio n s are to be su b m itted in duplicate. illustrations & tables b/w head and sh oulders p h oto o f the authors(s) shou ld accom pany article. slides & p rin ts, g ra p h s tables etc on eith er colour or b/w w hich w ould com ­ plem ent th e article are w elcom ed. tables should carry r om an num erals and illustrations a rabic n u m erals thu s 1 ,2 ,3 etc. references as for scientific articles. _____ _____________________________________________ 5 s p o r t s g e n e e s k u n d e vol. 5 n r . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) from bencard reufenn a b u m e t o n e the anti-inflammatory that improves functional mobility ^ ... j marketed by bencard division of beecham phirmici reono. 74/03968/07 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) epidemiology an epidemiological study of failure to complete a long-distance sea swim d yach sum m ary a postal questionnaire survey was used to compare the characteristics o f swimmers who failed to com plete a 3 kilometer sea swim to those who completed the swim. swimmers who failed to com plete the swim reported significantly higher rates o f headache and severe shivering compared to successful swimmers. only previous participation in a cycling marathon was related to failure. age, sex and body mass index being non-significant. i n t r o d u c t io n in m arch 1988 nin ety -th ree sw im m ers took part in a 3.2 kfn sw im from clo velly to sim onstow n. t h e usually w arm indian ocean on th at day was m easured at 16°c. t h e p articip an ts included experienced sw im m ers, tri-athletes and casual sw im m ers. a high p ro p o rtio n of p articip an ts (24,7% ) failed to com plete the race and had to be rem oved from the w ater by the p atrolling crews. f ollow ­ ing the race, a great deal o f concern was expressed about th e need for w etsuits in fu rth e r sw im s. t h e aim of this study was to assess w h eth er those sw im m ers who successfully com pleted the event differed from those w ho d id not co m ­ plete th e event and to evaluate th e need for w etsuits in fu tu re events. m e t h o d s addresses, tim es (if they com pleted the sw im ), age and sex was obtained from the c ape long d istance s w im m ing a s­ sociation, the organisers o f the event. all p articip an ts w ere m ailed a q u e s ­ tionnaire. t h e q u estio n n aire contained q uestions about th e d em ographic characteristics of sw im m ers, their height and w eight, th eir p rio r p a rtic i­ pation in a n u m b e r o f sp o rts even ts, w h eth er they had a n u m b e r o f sy m p ­ tom s, and th e ir a ttitu d es to w etsuits. t h e q u estio n n aires w ere m ailed b e ­ tw een ten days and two weeks after com pletion of the swim. r e s u l t s f o r the 70 who com pleted the sw im , tim es varied betw een 42.5 m in u tes and 153.5 m inutes (m e d ia n = 6 i ; in terq u an tile range 50-68). a relatively high re ­ sponse rate to the q u estio n n a ire (75%) was obtained. t h e d istrib u tio n o f re­ sp o n d en ts and n o n -re sp o n d e n ts was sim ilar w ith respect to th e ir com pleting tim e as well as the p ro p o rtio n who did not com plete the swim . it was felt likely therefore, th a t the re sp o n d e n ts w ere represen tativ e o f all p a rtic ip a n ts (table 1). f o r analysis, sw im m ers w ere initially divided into those w ho com pleted the swim and those who d id not com plete the swim. f u rth e r analyses split the gro u p of those who com pleted the swim into those w hose tim e was below the m edian tim e and those above the m e­ dian tim e for com pletion (i.e. 61 m in ­ utes). t h e age, sex and height d istrib u tio n s a com plete list o f all p a rticip an ts, their table 1: characteristics o f respondents versus non-respondents time taken respondents non-respondents (%) all derek y a c h m b c h b (epidemiology) m p h centre fo r epidemiological research in southern africa (c e r s a ) s a m edical research council pc>box70 t y g e r b e r g 1505 < 5 0 minutes 12 2(14) 14 50-59 minutes 14 5(28) 18 60-74 minutes 20 7(27) 27 75 + minutes 5 5(56) 9 n ot com plete swim 19 4 (1 7 ) 23 total 70 23(25) 93 ------------------------------------------------------------------- 7 s p o r t s g e n e e s k u n d e vol. 5 n r . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) epidemiology for those who com pleted and did not com plete the sw im w ere sim ilar (table 2). t h e w eights o f those w ho com pleted the swim w ere 4 kg h igher and their body mass index as well was h igher than those who did not com plete the swim. t hese differences, however, w ere not statistically significant. t h e percentage p articipation in the 1988 p eninsula m arath o n and the 1987 r o b b en island relay c hallenge show ed no differences betw een those w ho com pleted and table 2: comparison o f demographic and sports participation charac­ teristics o f swimmers completed failed 3.2 km swim to compete (n = 53) (n = 17) sex (percent male) 90.2 89.0 a ge* 29.9 (11.4) 25.8 (11.2) height * 1.80 (0.1) 1.8 (0.1) weight * 76 (13) 72 (23) body mass index* 24 (2.6) 24.0 (5) participation in + ’88 argus cycle tour ** 26 (49) 15 (88.2) ’88 peninsula marathon 19 (35.9) 7 (41.2) ’87 robben island relay challenge 5 (9.4) 1 (5.9) ’87 3.2 km glencairnsimonstown swim 14 (26.4) 6 (35.3) n u m b er (percent) ** p = 0.004, w iicoxon test m edian (interquartile range) *** p = 0,007, w iicoxon test table 3: comparison o f demographic and sports participation characteristics o f swimmers w ho completed the 1988 3.2 km swim variable * t im e <61 minutes tim e >61 minutes age (years) 25 (9.7) 33 (17) height (metres) 1.8 (0.1) 1.8 (0.1) weight (kilograms) 78 (13.5) 75 (13.3) body mass index 24 (2.8) 24 (3.0) ’“'median (iqr) participation in + ’38 argus cycle tour * 6 (24) 18 (69.2) ’88 peninsula marathon ** 5 (20) 12 (46.2) ’87 robben island relay challenge 4 (16) 1 (3.9) ’87 3.2 km glencairnsimonstown swim 9 (36) 5 (19.2) num ber (percent) p = 0.001, x 2 test ** p = 0.05, x 2 test those who failed to com plete the swim. t h e re was a statistically significant dif­ ference in the p ro p o rtio n o f those who com pleted th e a rgus cycle tour w ith 88.2% o f those w ho failed to com plete the swim having participated in the tour com pared to 49% o f those who d id not. t h e ho u rs spen t train in g showed that there was a significant difference in the am ount of h o u rs spent train in g p a r­ ticularly w ith respect to cycling. a sim i­ lar tren d w ith respect to tim e taken tc com plete the sw im was found (table 3). a m ultiple logistic regression yielded sim ilar results to the univariate a p ­ proach in th at only cycling was signi­ ficantly related to failure w hen age, sex and body mass index w ere controlled for. t h e sym ptom s o f sw im m ers who com pleted and d id not com plete the swim are show n in table 4. it can be seen th at there was a statistically signi­ ficant difference betw een the groups w ith respect to headache. t h e highest pro p o rtio n being rep o rted am ong those who w ere unsuccessful. it should be noted that for all o th er sym ptom s the p ro p o rtio n was h ig h er am ong those w ho w ere unsuccessful. w hen the suc­ cessful com petitors w ere divided into two g roups according to the tim e that took them to com p lete, there w ere also statistically significant differences w ith respect to headache, difficulty talking and severe shivering w ith the highest propo rtio n s being re p o rted am ong the slowest com petitors (table 5). 32.9% o f all particip an ts felt that w etsuits should not be allowed in swims. t h e re was no difference in re­ sponse to this q u estio n betw een those w ho com pleted and those w ho d id not com plete the sw im n o r was th eir a tti­ tu d e influenced by th e ir tim e taken to com plete th e swim. t h e re was a relatio n sh ip betw een the longest sea sw im com pleted and the su c ­ cess rate. all o f those w ho had com ­ pleted sw im s g reater o r equal to 5 km successfully finished the race, com pared to 90% o f those w ho com pleted a p rio r 3 km sea swim and 8% o f those w ho had sw um sh o rter distances in the sea. co nclusio ns n o p u b lish ed epidem iological studies 8 -----------------------------------------------------------s p o r t s m e d i c i n e vol. 5 n o . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) epidemiology table 4: symptoms o f swimmers * completed the 1988 swim ( n = 53) failed to com plete the 1988 swim (n=17) p-value m uscle cramps 15.7 33.3 0.109 vomitting 1.9 0.0 .550 disorientation 25.5 33.3 .522 headache 7.8 33.3 0.008 nausea 7.8 16.7 .286 difficultly walking 45.1 66.7 .116 difficulty talking 31.4 50.0 .158 severe shivering 60.8 83.3 .081 percentage w ithin group table 5: s ym ptom s o f sw im m ers w ho com pleted the swim t im e < 61 tim e minutes minutes (n=26) (n=27) m uscle cramps 12 19.2 vomitting 0 3.9 disorientation 24 13.8 headache** 16 0 nausea* 0 15.4 difficulty walking 40 50 difficulty talking** 16 46 severe shivering** 40 80.8 0,1 < p < 0 . 0 5 p < 0 .0 5 logistic to control age, sex, bmi marathon r i relay cycle or 14.0 or = 9 from university 95% cl (2.3 83.9) completed (51) n ot (18) p sex %male 90.2 89.0 .875 age % > 27 yrs 54.9 44.4 .445 bmi % a 2 5 44.0 50.0 .943 cycle tour 47.1 89.0 .002 marathon 33.3 44.4 .339 ri relay 9.8 5.6 .503 have exam ined reasons for failure to com plete sw im s. c ape rep o rts u n d e r ex­ perim ental conditions have show n that respiratory reflexes and h y p o th erm ia at 4.7°c result in early failu re.(l'2) t h e increased in terest especially by tri-ath ­ letes in sea sw im s at te m p e ra tu res below 20°c, dem ands g reater atten tio n by researchers to d e term in an ts o f failure if deaths due to h y p o th erm ia are to be prevented. t h is stu d y shows that age, sex an d body mass in d ex w ere not re­ lated to the likelihood o f com pleting a swim at 16°c, nor the tim e taken to com plete it. t h e m ajor d e term in an t or factors related to a likelihood o f com ­ pleting are related to p rio r long distance sea experience and heavy p rio r partici­ pation in cycling (as a negative factor). t h e sym ptom s m ost able to d istin ­ guish betw een failure and success both in absolute and relative term s were headache and shivering. f u rth e r w ork is req u ired to d e term in e th e predictive value o f a headache w hile sw im m ing for severe h y p o th erm ia. t h is will certainly be o f use to athletes train in g for future events as well as p articip atio n d u rin g such events. it should be noted that all sw im m ers had to w ear com pulsory headgear. t h e im plications o f the study for fu tu re sw im s are th at stric te r attention may need to be played to en su rin g that p a rticip an ts, particu larly cyclists, in ­ crease th eir sw im m ing train in g . t h e need for w etsuits was not evaluated in this study. since this event is part o f the tri-athlete circ u it, it m ay be advisable to suggest that w etsuits be w o rn at fu tu re events. f u rth e r research is re q u ired u s ­ ing m easures o f fat co n ten t to d eterm in e pred icto rs o f h y p o th e rm ia . ac k n o w ledg em en ts t h e cape l ong d istan ce sw im m ing a ssociation for th eir assistance in co n ­ d u ctin g the study, p ro f t im n oakes for useful com m ents on an earlier draft of the m an u scrip t and th e sw im m ers for responding. references 1. editorial. survival in cold water. b r me d 7 1969; 1:459. 2. keatinge w r , prys-r oberts c, cooper k e , h onour aj, haight j. sudden failure of swimming in cold water. b r m e d j 1969; 1: 480-483. s p o r t s g e n e e s k u n d e vol. 5 n r . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports injuries lower limb compartment syndromes clive n obel j i \ a ) > anterior tibial compartment 1 0 ----------------------------------------------------------s p o r t s m e d i c i n e vol. s n o . 3 a n t e r io r tibial c o m p a r t m e n t s y n d r o m e *** t h is c o n d itio n m ay be a surgical em ergency as m uscle death will ra p ­ idly occur, giving rise to v o lk m an n ’s ischaem ic co n tra c tu re . s y m p tom s in th e severe trau m atic variety, often associated w ith fractu res o f th e tibia and fibula, th e sy m p to m s and signs include: • pain • p allo r • p arasthesia • pulselessness • paralysis in th e exercise variety, th e sy m p to m s are usually o f a ch ro n ic n ature. • a cu te rarely, this c o n d itio n m ay be acute w ith ex trem ely severe pain follow ed by loss o f fu n ctio n w ith in 4-6 h o u rs. p aralysis and anaesthesia o f the area su p p lied by th e involved p e ­ rip h eral nerve rap id ly ensues. • c h ro n ic t his is fo u n d c o m m o n ly in ru n ­ ners. p rogressive pain and te n ­ sion in th e c o m p a rtm e n t ensues on ru n n in g , and the fo o t loses d o rsiflex io n s tre n g th causing it to “s la p ”. parasthesia (usually pin s and needles) m ay develop. c h ro n ic s y m p to m s usually follow severe unaccu sto m ed exercise. signs • tense, te n d e r a n te rio r c o m p a rt­ m e n t w h ich is m ark ed in acute cases. • m o st cases have dorsalis pedis pulse intact. • m o st cases have h y p eresth esia on the d o rsal aspect o f the first web. • s y m p to m s m ay be elicited by rap id an k le m ov em en ts w ith the p a tie n t lying supine. t h e lo w er leg is divided in to th ree fas­ cial c o m p a rtm e n ts: t h e in tero sseo u s m em b ran e divides th e leg in to an te rio r and p o s te rio r c o m p a rtm e n ts. t w o septa attach ed to th e fibula on its lateral aspect, fo rm a lateral co m p a rtm e n t. e x cep t fo r b lo o d vessels, nerves and te n d o n s leaving th e c o m p a rtm e n ts these areas are essentially closed spaces. t h e an terio r c o m p a rtm e n t is e n ­ closed by th e tibia and th e fibula on the sides, by th e in tero sseo u s m em b ran e p o s te rio rly and by a fascial layer a n te ­ riorly. t h e p osterior region is divided into p o s te rio r deep and p o s te rio r superficial c o m p a rtm e n ts by a fascial layer. t h e lateral c o m p a rtm e n t is based on the fibula and is sep arated from the o th e r c o m p a rtm e n ts by a n te rio r and p o s te rio r fascial bands. e ach c o m p a rtm e n t is su p p lied by one m a jo r vessel and nerve. t h e p re ssu re in th e arterioles is a b o u t 40 m m h g (m ercu ry ). c a p illary p ress­ ure is betw een 20 and 30 mg h g and ve­ n o u s p ressu re is 10-15 m m h g . m echanism o f injury a n y c o n d itio n w h ich raises the p re ssu re in th e c o m p a rtm e n t above 40 m m h g will blo ck the b lo o d flow to th e m uscles w ith o u t inclu d in g the m a jo r arteries. in s p o rt tw o c o n d itio n s m ay raise th e in tra c o m p a rtm e n ta l p ressu re, nam ely tra u m a and exercise. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports injuries sports c o m p a rtm e n t s y n d ro m e s m ay o ccu r in any sp o rt, th e tra u m a tic variety being co m m o n in collision sp o rts. t h ey are m o re likely to o c c u r in as­ sociatio n w ith fractures. t h e exercise variety o f c o m p a rt­ m e n t s y n d ro m e s is co m m o n in e n ­ d u ra n c e sp o rts eg. long d istance ru n ­ ning. c o m p a rtm e n t s y n d ro m e s m ay o ccu r in eith e r sex b u t are fo u n d m o re co m m o n ly in m ales due to th e ir p a r ­ tic ip a tio n in collision sp o rts. sites o f these sy n d ro m e s include: • th e a n te rio r tibial c o m p a rtm e n t; • th e p o s te rio r tibial c o m p a rtm e n t; and • th e lateral c o m p a rtm e n t (p e ro ­ neal). d ifferen tial d iagn osis a n te rio r shin splin ts (tibial stress s y n d ro m e ). in v estig a tio n s t his is usually an easy clinical diag­ nosis b u t c o m p a rtm e n t p ressu re stu d ies are valuable in co n firm in g th e diagnosis. t reatm ent a c u t e *** t h is is a surgical em ergency and fascio to m y sh o u ld be carried o u t as so o n as possible. t he skin incision m ay also have to be left o p e n as th e m uscle sw ells ex­ cessively. t h e skin incision m u st be th e len g th o f th e c o m p a rtm e n t. c h r o n i c treat cause r e d u c tio n o f activity • t h e ru n n e r sh o u ld im m ediately reduce his p ro g ra m m e and s h o u ld th e re a fter build up p r o ­ gressively; • a void hill ru n n in g . treat r esu lt t h e m ark ed sw elling sh o u ld be tre a te d b y : • elevation; • icing; • n o n -ste ro id a l an ti-in fla m m a to ry d rugs. if th e c o n d itio n fails to re sp o n d to c o n servative tre a tm e n t, th en fascio­ to m y m ay be necessary. t h e a n te rio r t ibial c o m p a rtm e n t s y n d ro m e is fo u n d m ore c o m m o n ly in ru n n e rs. p rogressive pain and te n ­ sion in th e c o m p a rtm e n t ensues on ru n n in g , and th e fo o t loses dorsiflex ion s tre n g th causing it to “s la p ”. p o s t e r io r tib ia l c o m p a r t m e n t s y n d r o m e t his is n o t as c o m m o n an in ju ry as th a t o f th e a n te rio r t ibial c o m p a rt­ m ent. s y m p tom s pain in th e p o s te rio r c o m p a rtm e n t d u rin g and after ru n n in g and injury. signs tense, te n d e r p o s te rio r c o m p a rt­ m en t fo llo w in g exercise o r traum a. d ifferen tial diagn osis p o s te rio r tibial stress sy n d ro m e . in v estig a tio n s • p ressu re te stin g will clarify the diagnosis; • b one scan is o ften positiv e in tib ­ ial stress sy n d ro m e . treatm ent as fo r a n te rio r t ibial c o m p a rtm e n t sy n d ro m e . la ter a l tib ia l c o m p a r t m e n t s y n d r o m e s ym p to m s t h e features are th e sam e as those fo u n d in th e o th e r c o m p a rtm e n t s y n d ro m e s except th a t th e pain is lo ­ calised o v er th e lateral co m p a rtm e n t. t his is an u n c o m m o n c o n d itio n . p ero n eal nerve co m p ressio n m ay cause w eakness of eversion. t reatm ent as fo r a n te rio r t ibial c o m p a rtm e n t sy n d ro m e . this article is rep rin ted fr o m “the m a n u a l o f sports in ju r ie s ” b y c live n o b el. posterior tibial compartment ----------------------------------------------------------------- 11 s p o r t s g e n e e s k u n d e vol. 5 n r . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition protein in the diet m faber p ro te in is an essential stru c tu re o f all living m atter. t h e cells in th e b o d y are in a d y n am ic state o f c o n tin u o u s d e ­ s tru c tio n and resy n th esis o f p ro tein w hich facilitates th e reg en eratio n of cells. t he p ro te in s in the b o d y are in ­ evitab ly d e p e n d e n t fo r th e ir fo rm a tio n and m ain ten an ce on th e p ro te in s in the diet. a lth o u g h p ro te in s are an essential life-fo rm in g and life-su stain in g in g red i­ en t o f the d iet, it w o u ld n o t be a p p ro ­ p ria te to state th a t p ro te in s are m o re im p o rta n t th an o th e r n u trie n ts. d iffe r­ en t n u trie n ts have d iffe re n t fu n ctio n s, all of w hich are im p o rta n t to m ain tain a h ealth y body. t h e fu n c tio n s o f p ro te in can be divided in to tw o m ain categories viz. p ro te in s necessary fo r g ro w th and m ain ten an ce, and p ro te in s th a t regulate b iological processes. p rotein s are necessary for g r o w th and m a in ten a n ce • p ro te in s c o n s titu te th e chief solid m a tte r o f m uscles, org an s and en d o c rin e g la n d s ; • p ro te in s are m a jo r c o n stitu e n ts of skin, nails, h air and the m atrix of b o n es and te e th ; • p ro te in s are m a jo r c o n stitu e n ts of b lo o d cells and serum . p rotein s are in v o lv ed in and reg u la te biological processes • plasm a p ro te in s play a role in the reg u latio n of osm o tic p ressu re and w ater balance; m ie k e faber, research in s titu te fo r n u tr itio n a l diseases, m edical research c ouncil, tygerberg. • the b o d y ’s resistance to disease is m ain tain ed in p a rt by an tib o d ies w hich are p ro te in in n atu re; • m etab o lic p rocesses are regulated by e n zy m es w h ich are p ro te in in n a tu re ; • m o s t h o rm o n e s are p ro te in in n a ­ tu re. u n d e r n o rm a l c o n d itio n s, these fu n ctio n s are m ain ta in e d , p ro v id ed th a t th e en erg y c o n te n t o f the d iet is adequate. s h ould c a rb o h y d ra te s and fat fail to su p p ly e n o u g h calories, th en p ro te in is utilised fo r energy. u n d e r these circum stances sy m p ­ to m s of p ro te in deficiency m ay ap ­ pear, even w hen th e am o u n t o f p r o ­ tein is adequate. p ro te in s are d istin g u ish ed from c a rb o h y d ra te s and fat by th e p re s­ ence o f n itro g en in the m uscle. it is m erely of this difference th a t the place o f p ro te in in the diet c a n n o t be replaced by c a rb o h y d ra te s o r fat. p ro te in s co n sist of u n its called am in o acids, w hich are linked t o ­ g e th e r to fo rm th e p ro te in m olecule. p ro te in s d iffer in the am o u n ts o f the vario u s am in o acids and th e ir a r­ ran g em en ts. t he q u ality o f the p r o ­ tein (also k n o w n as th e biologic value) is d e te rm in e d by th e sequence of th e am in o acids. t h e am ino acid c o m p o sitio n of th e p ro te in in eggs is som etim es used as a stan d ard against w hich th e q u a lity of o th e r p ro te in s are co m p ared . egg p ro te in s, m o st of w h ich are alb u m in s in th e w h ite o f 1 2 ----------------------------------------------------------s p o r t s m e d i c i n e vol. 5 n o . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition th e egg, have th e h ig h est biologic value o f all p ro te in s. t h e re are c e r­ tain am in o acids (th at are in d isp e n s­ able to life and g ro w th ) w h ich the h u m an b o d y c a n n o t m ake fo r itself. t hese are called th e essential am ino acids and th e y m u s t be o b tain ed fro m th e diet. t h e a d u lt h u m an b o d y can m ain tain n itro g e n o u s e q u i­ lib riu m on a m ix tu re o f these eight essential am in o acids, as th e sole so u rce o f n itro g e n . d e p e n d in g u pon th e ir ab ility to m ain tain life and p r o ­ m o te g ro w th , p ro te in s have been classified as eith e r co m p le te o r in ­ co m p lete. c o m p lete p rotein s c o n tain all th e es­ sential am in o acids in q u an tities su f­ ficient fo r m ain ten an ce o f th e tissues and fo r n o rm a l rate o f g ro w th . such p ro te in s are said to have a high biologic value. t hese p ro te in s are of anim al o r i­ gin and include eggs, cheese, m ilk, m eat, p o u ltry and fish. in co m p lete p rotein s can be divided in to tw o classes: • partially in com p lete p rotein s can m aintain life, b u t th ey lack suf­ ficient a m o u n ts of som e o f the am in o acids necessary fo r g ro w th . t hese p ro te in s are o f p la n t origin and inclu d e p ro te in in cereals, le­ gum es and nu ts. • to ta lly in co m p lete p rotein s are in ­ capable o f replacing o r b u ild in g new tissues, and hence c a n n o t s u p p o rt life, let alone p ro v id e g ro w th . t hese p ro te in s inclu d e th e p ro te in s in gel­ atine. f ro m th e above classification, it can be seen th a t p ro te in s are eith e r of animal o r p la n t o rig in . w ith th e ex cep tio n of gelatin, all anim al p ro te in s are co m p lete and of high biological value. m o st p lan t p ro te in s (w ith th e ex cep tio n o f w heat germ ) lack o n e o r m o re essential am ino acid in sufficient am o u n ts. t h e lacking am in o acid is k n o w n as th e lim itin g a m in o acid. t h e p ro te in s in w h eatg erm are, alth o u g h o f p la n t o rig in , o f high biologic value. n o t o n ly is anim al p r o ­ tein o f h ig h e r q u a lity than p lan t p r o ­ tein , b u t p ro p o rtio n a lly anim al foods c o n tain m o re p ro te in than p la n t foods. f ru it and vegetables have v ery low (if any) p ro te in c o n c e n tra tio n s. as a rule, less anim al th an p la n t p ro te in is necess­ ary to p ro v id e e n o u g h o f all the essen­ tial am in o acids. a lth o u g h p lan t p ro te in s lack certain am in o acids, th e ir role in the d iet sh o u ld n o t be u n d e re stim a te d . t he sh o rtag e o f th e lacking am in o acid can be o v erco m e b y ad d in g a n o th e r p ro tein w h ich c o n ta in s th e m issing am ino acid. t h e capacity o f p ro te in s to m ake g ood o n e a n o th e rs deficiencies is k n o w n as th e ir su p p lem en ta ry value. w hen an app reciab le a m o u n t o f p la n t p ro tein is fed w ith o n ly a small a m o u n t o f anim al p ro te in , th e q u ality o f th e m ix tu re is of a p p l i c a t i o n f o r research grant to p ro m o te k n o w le d g e a b o u t th e role o f sugar in h e a lth a n d nutrition, th e south a fric a n sugar a ssociatio n looks to th e s cie n tific c o m m u n ity for re lia b le a n d u p -to -d a te in fo rm a tio n . as p a rt o f this process, it supports scie n tific rese arch p ro je cts d e s ig n e d to c la rify issues w h ic h arise in this p u b lic terrain. the sugar a ssociation a c ts o n th e re c o m m e n d a tio n s o f a research a dvisor a n d advisory panel. priorities for research fu n d in g b y th e a ssociatio n are; 1 physical w ork, exercise or sport in re la tio n to d iet. 2. o besity a n d th e c o m p a ra tiv e role o f d iffe re n t d ie ta ry fa cto rs a n d form s o f exercise. 3. causes o f d e n ta l caries a n d p e rio d o n ta l disease. 4. diet in relatio n to d ia b e te s mellitus. 5. h yp e rlip id a e m ia s in re la tio n to diet. 6. g ly c a tio n o f proteins. proposals in a n y o n e o f these priority fields will b e g iv e n co n s id e ra tio n . the research grants are a w a rd e d o n a 2 ye a rly basis. c o n tin u a tio n o f th e g ra n t for th e s e c o n d y e a r o f study is d e p e n d e n t on progress m a d e , as assessed b y th e advisory panel from a re p o rt s u b m itte d for this purpose. instructions for proposal preparations: in o rd e r to a llo w for a p ro p e r e v a lu a tio n o f proposals b y reviewers, th e fo llo w in g items should b e in c lu d e d : 1. o n e p a g e a b s tra c t o f th e p ro p o s e d p ro je c t (200-w ord m a xim u m ) 2. short d e scrip tio n o f b a c k g ro u n d for p ro p o s e d p ro je c t research. 3. s u c c in c t s ta te m e n t o f p ro je c t o b je ctive s. 4. short d e scrip tio n o f m e th o d s to b e used in pursuing ob je ctive s. 5. c le a ra n c e for th e research from a n a n im a l or h um an review c o m m itte e if a p p lic a b le . 6. c urriculum v ita e a n d list o f fu ll-le n g h p u b lic a tio n s ove r th e last six years. 7. d e ta ile d b u d g e t (to in c lu d e th e p ro p o s e d b u d g e t for th e first a n d s e c o n d years o f study). note: no funds a re p ro v id e d for m a jo r e q u ip m e n t (unit c o s t g re a te r th a n r2 000) or tra v e l costs, the d e a d lin e for proposals to b e s u b m itte d is 15 n o v e m b e r 1990. a p p lic a tio n form s are a v a ila b le from a n d . w h e n c o m p le te d , should b e re tu rn e d to: the nutritionist, the south a fric a n sugar a ssociatio n, po box 374, durban 4000. tel. (031) 305 6161. n either la te a p p lic a tio n s nor a p p lic a tio n s re c e iv e d b y facsim ile will b e a c c e p te d . ----------------------------sugar association s p o r t s g e n e e s k u n d e vol. 5 n r . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition high value. f o r exam ple, cereal foods are usually low in an am in o acid called lysine, b u t m ilk supplies am ple a m o u n ts o f th e m issing lysine. t h u s, m acaro n i and cheese, cereal and m ilk o r b read and cheese are supplem entary. l ikew ise, a relatively small a m o u n t of m eat, egg o r cheese in a rice, n o o d le o r m acaro n i casserole is an effective c o m ­ b in a tio n . f o r th e b est use o f p ro te in fo o d s, so m e c o m p le te p ro te in shou ld be in clu d ed in each o f the meals o f the day, ra th e r th an allo tin g all o f it to one meal. because o f th e s u p p le m e n ta ry effect, diets c o n sistin g e n tire ly o f a w ide v ar­ iety o f p la n t sources can adeq u ately m eet th e p ro te in needs o f h ealthy adu lts, p ro v id e d th a t th e d iet con tain s sufficient energy. t h is can be achieved b y ch o o sin g a variety o f p la n t foods (eg. legum es, cereals and n u ts) and fu r­ th e rm o re , a variety o f each kin d (eg. m aize, w h eat, oats and rice all cereals; and so y a and o th e r d ry beans, peas and lentils all legum es). p lan t fo o d s s u p ­ p le m e n t o n e a n o th e r exceptionally well. m o st n u ts have a high p ro te in c o n te n t. o f all the n u ts, p e a n u ts have th e hig h est p ro te in c o n te n t, b u t the p ro te in is in co m p lete. t h e sh o rtag e can be o v erco m e by ad d in g w h eat p ro te in . t h e re fo re , the p ro te in q u ality o f a pea n u tb u tte r san d w ich is o f high value. t h e p ro te in in p e a n u ts can also be s u p ­ p lem en ted w ith th e p ro te in in m aize, rice, c o c o n u t and oats. pulses have a h ig h er p ro te in c o n te n t th an cereals. pulses lack th e essential am in o acid m e th io n in e , b u t are rich in lysine. o n th e o th e r h an d , w h eat p ro te in s lack ly ­ sine b u t su p p ly ad eq u ate a m o u n ts o f m eth io n in e . b ecause o f this, a c o m b i­ natio n o f pulses and cereals such as soyabeans and w h eat, rice and lentils as well as sam p and d ry beans m ay have a n u tritiv e value as g o o d as anim al p r o ­ tein. pulses can also be su p p lem en ted by sesam e. it m u st be k e p t in m in d th at, in o rd e r to m ain tain th e su p p le m e n ta ry effect, th e s u p p le m e n ta ry foo d s m u st be in clu d ed in th e sam e meal. c o n ­ sum in g lentils fo r s u p p e r will d efinitely n o t su p p le m e n t th e rice value th a t was in clu d ed fo r lunch. it is re c o m m e n d e d th a t, u n d e r n o r ­ mal circu m stan ces, th e p ro te in in tak e o f h ealth y a d u lts sh o u ld be 0,8 g p ro te in p e r kg ideal b o d y w eight. a n ad u lt m an w eighing 70 kg and a w o m an w eighing 58 kg th e re fo re req u ire a b o u t 56 and 46 g p ro te in p e r day respectively. u n d e r n o rm al circu m stan ces by typical w esternised d iet su p p ly m ore than e n o u g h p ro te in and n o su p p le m e n ­ ta tio n o f th e d iet w ith special p ro te in rich com m ercial p ro d u c ts is necessary. in clu d ed is a list o f th e p ro te in c o n ­ te n t o f certain foods. all values are given fo r 100 g edible p a rt o f the food item . t h e given values th erefo re give a good in d icatio n o f th e p ro te in c o n cen ­ tra tio n s o f d iffe re n t food item s. average p r o t e in c o n t e n t per 100 g edible part o f the f o o d f ood item p rot(g) food item p rot(g) skim m ed m ilk p o w d e r 36,2 venison, roasted 35,0 biltong, beef 34,3 lean m eat: beef, m u tto n , p o rk 29,5 chicken, light m eat o nly 28,9 tuna, canned in w ater 28,0 peanuts 26,0 p e a n u tb u tte r 25,2 cheese: cheddar, gouda, edam 24,9 fatty m eat: beef, m u tto n , p o rk 24,9 chicken, w ith skin 24,7 kidney, fried, lam b 24,6 sunflow er seeds 24,0 tro u t, steam ed 23,5 haddock, boiled 23,3 p ro n u tro 22,0 ham , sm oked 20,9 fish, steam ed 20,5 cheese: cam em bert, brie 19,8 abalone, crayfish 18,7 alm ond nuts 18,6 special k 18,0 cottage cheese, fat free 17,3 cashew n uts 17,2 mussels, boiled 17,2 cheese spread 16,4 all bran flakes 15,1 tripe, cooked 14,8 w alnuts 14,8 b ra z iln u ts 14,3 puffed w h eat 14,2 feta cheese 14,2 vienna 14,0 cottage cheese, low fat 13,7 rye crisp bread eg r yvita 13,0 muesli 12,9 p o p c o rn 12,8 h a z e ln u ts 12,6 cottage cheese, creamed 12,5 eggs, boiled 12,1 weetbix 11,4 w holew heat crispbread eg provita 11,2 soyabeans, cooked 11,0 m atzos 10,5 bread, w holew heat 9,9 flour, cake 9,8 p o lo n y 9,4 to p p ers, cooked 8,7 co rn flak es 8,6 bread, w hite 8,4 oysters, raw 8,4 lentils, cooked 7,8 cream cheese 7,6 b u tte r beans, cooked 7,1 evaporated m ilk 6,8 haricot beans, cooked 6,6 rice crispies 5,9 peas, cooked 5,4 baked beans 5,1 dried apricots 5,0 brussel sprouts, cooked 4,2 pasta eg m acaroni, spaghetti, noodles 3,4 skim m ed m ilk, w hole milk, b utterm ilk, y o g h u rt 3,3 mealie 3,3 dried peach, pear 3,1 broccoli, cooked 3,1 spinach, cooked 3,0 tastee w heat 2,9 raisins 2,5 b ro w n rice, cooked 2,5 w hite rice, cooked 2,0 vegetables 0-3 fruit 0-2 fats 0 sugar 0 14 ----------------------------------------------------------s p o r t s m e d i c i n e vol. 5 n o . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) is your patient being held prisoner to pain and immobility? there is a release... \ non-steroidal anti-inflammatory . relieves pain „ -v< . reduces inflammatl . restores mobility | . reduces the cost ol trauma therapy available nyw in three rfo: panamor" 25 tablet panamor* at 5 0 tabi and introducing' panamor® 75 intecji release from len n o n ^ ^ limited lit s' m v jic in c y o u o m affo rd »c irus* r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy update physiotherapy and the sprained ankle of the sportsman p h y sio th e ra p ists like to tre a t so ft tissue injuries o f th e ankle as so o n as possible. f ew er th an 10% o f ankle injuries s h o u ld be tre a te d in p .o .p . l igam ents need to m ove b u t be co rre c tly s u p ­ p o rte d , h ence th e use o f strap p in g s o r a brace. t he aim s o f th e p h y sio th e ra p ist in th e acu te stage o f 48 h o u rs a r e : • to red u ce p a in ; • to red u ce sw elling; • to m in im ize th e size o f th e haem a tom a. in th e su b acute stage after 48 h o u rs u n ­ til re so lu tio n , th e aim s a r e : • to achieve p ain -free and full jo in t range w ith as sm all and as m alleable a scar as p o ssib le; • to re -ed u cate p ro p rio c e p tio n ; • to re-e d u c ate m uscle pow er. r e so lu tio n is w h en th e p a th o -p h y s io logical m echanism has tak en place. it m u st be re m e m b e red th a t ligam ents 3 take six w eeks to heal b u t to p s p o rts ­ m en usually resu m e th e ir s p o rt long b e­ fore this tim e. it m u st be rem em b ered th a t o th e r stru c tu re s such as capsule o r p ero n e i te n d o n s m ay have been injured as well. 16 s p o r t s m e d i c i n e vol. 5 n o . 3 1 a p ain -free range is achieved w ith th e use o f tran sv erse frictio n s, pass­ ive and active m ovem ents. 2 p ro p rio c e p tio n is th e p e rs o n ’s ab il­ ity to a p p re h e n d changes o f p a rts o f th e b o d y w ith o u t th e aid o f sight. it is a balance o r rig h tin g reflex and it is lo st w hen th e ankle is inju red . r e-e d u c a tio n begins in th e s u b ­ acute stage w h ilst th e ankle is still stra p p e d . t h e p ro g re ssio n is from th e sim ple exercise o f stan d in g on th e in ju red leg and balancing w ith th e eyes closed, to exercising o n the w o b b le b o a rd . f ro m this b o a rd the p a tie n t p ro g resses to a n ew in v en ­ tio n , recen tly p a te n te d called the e x -o p e d . t h e stan d in g exercise on th e b o ard enables th e ankle to reach th e extrem es o f m o v em en t b u t sto p s excess m o v e m e n t th erefo re does n o t p u t th e ankle at risk o f re­ injury. p h y sio th e ra p ists th ro u g h o u t the c o u n try are using iso k in etic a p p a r­ atus. f irstly it is used to test th e p o w e r of th e o p p o sin g m uscles o f a jo in t eg. d o rsiflex io n (t ibialis a n te rio r) and p lan tarflex io n (g a stro c n e m iu s and soleus) o r eversion (p ero n eu s l o n g u s and b revis) and inversion (t ibialis a n te rio r o r t ibialis p o s te ­ rio r). secondly, it is used to re ­ ed u cated th e m uscles to th eir stre n g th . s tab ility o f a jo in t is n o t o n ly d e p e n d e n t on ligam ents b u t also o n stre n g th of m uscle. if the o p p o sin g m uscles o v er th e jo in t have th e c o rre c t p o w e r balance, th a t jo in t is stable. a lth o u g h iso k in etic m achines are n o t n ew , th e re has been a surge o f in terest in th em because o f the g ro w in g field o f sp o rts m edicine. d u rin g th e final stage o f reh ab ilitatio n , in o rd e r to re-e d u c ate the ankle to fu n c ­ tional fitness, a p lay er m u st practice m o v em en ts o f his s p o rt eg. a ru g b y back m u st ru n in zig -zag and figure o f eight p a tte rn s, h o p on alternative feet, and p ractice quick stops. o n ly if the ankle has gained its range, stre n g th and p ro p rio c e p tio n can the p la y e r re tu rn to his sp o rt. t h e ankle sh o u ld be assisted th ro u g h th e rest o f th e season by the use of a stra p p in g o r brace such as the p n e u ­ m atic brace filled w ith air cells. r e­ search has p ro v e d this to be a su p e rio r brace. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) soccer soccer warming up and stretching g jacobson and e speechley soccer has been played for m any years. t h ere are indications that it was played as long ago as 12 b.c. d u rin g the reign of the h an d ynasty in c h in a, p red o m i­ nately by the m ilitary in o rd e r to e n ­ courage discipline and c o m ra d e sh ip .1 a striking feature o f the gam e was th at the players used the severed head o f an enem y w arrior as the ball! n ow som e 2000 years later the p o p u larity o f the game has spread to such an extent that both m en and w om en on six co n tinents are playing th e gam e regularly and co m ­ petitively. in 1984, soccer surpassed ru g b y as the m ost p o p u la r sport in south a frica.2 t h e p o p u larity o f soccer has b ro u g h t w ith it an increase in the n u m b e r o f in ju ries, m any o f w hich can how ever be p revented by the adoption o f correct train in g principles. a recent stu d y 3 reco m m en d ed that ad eq u ate w arm u p and stretch in g program m es should be included into train in g p ro ­ gram m es, as this m ay lead to a decrease in the n u m b e r o f footballing injuries. w arm ing up and stretch in g are vital c om ponents o f any successful training program m e. warmup w arm ing u p increases the te m p e ra tu re of the body. t h is increased te m p eratu re results in the increased su p p ly o f blood and n u trie n ts to th e m uscle, and also causes the m uscle to con tract m ore ef­ ficiently. t h e increased tissue te m p era­ tu re that results from th e w arm u p regary jacobson b s c (physiotherapy) w i t s bsc(m ed)(h ons) sports science u c t e va n speechley b s c (physiotherapy) w i t s duces the incidence o f m uscular injuries. a thletes w ho w arm u p before a m atch tend to be m ore m entally p re ­ pared for the g a m e .4. t h ree m ajor types o f w arm up can be used. passive t h is type of w arm u p involves the w arm ing u p o f th e body by external m eans. in th e south african clim ate this is seldom necessary. h ow ever the player may benefit if he w ears a full track suit before playing as this m ay act as a w arm ­ ing up m edium . general t h is is the m ost com m on type o f w arm u p used. in this case, the b ody te m p era­ tu re is raised by the active, co-ordinated m ovem ent o f various m uscle g roups. exam ples o f this type o f w arm u p in ­ clude jogging and arm c irc lin g . specific t h is is possibly th e m ost beneficial form o f a w arm up . t h e body te m p e ra ­ tu re is raised by th e p erfo rm an ce o f the same m ovem ents th at are used d u rin g m atchplay only this tim e th e m ovem ent is perform ed at a slower, m o re leisurely pace. t h e advantage o f su ch a w arm up is that not only does it increase the tem ­ p eratu re o f the b ody parts d irectly in ­ volved in the activity, b u t it also acts as a dress rehearsal for th e m atch. exam ples o f this type o f w arm u p inclu d e d rib ­ bling and h eadering the ball. how m u c h a n d how long? t h e w arm u p m u st be individualised according to the players physical capa­ bilities. c o n ditioned athletes regulate the am o u n t o f heat p ro d u ced d u rin g exercise very effectively, an d therefore probably re q u ire a longer an d m ore in ­ tense w arm u p .4 bearing in m in d the re ­ strictions placed on th e p lay ers, a 15-20 m in u te pre-gam e w arm u p p erio d , should be ad eq u ate. t h ere should not be a rest interval betw een the w arm up and the m atch. t h e len g th o f tim e o f the w arm up m u st not be too long as this m ay tire th e players and resu lt in poor perform ance d u rin g th e m atch. an easy guideline can be used to assess w hen a player is sufficiently w arm ed up . a slight, b ut noticeable sweat (usually on the forehead) should be d etectable. str etch ing an ad eq u ate w arm up p eriod should precede all stretch in g . it is incorrectly believed th at cold m uscles, being m ore plastic, are m ore likely to u n d erg o p e r­ m anent ch an g e, w hen stre tc h e d .5 t h e objective b eh in d stretch in g is to in ­ crease the len g th o f the connective tis­ sue (su p p o rtin g tissue a ro u n d th e m u s­ cle) perm anently, and to increase the length o f th e m uscle transiently. s tretching results in th e m uscle being m ore flexible, and as tight m uscles p re ­ dispose to injury,6 stretch in g may d e ­ crease the incidence o f m uscu lar and ten d in o u s injury. flexibility is a co m p o ­ n en t o f fitness th at is h ealth , not skill re­ lated, and is defined as “th e range o f m ovem ent a ro u n d a specific jo in t”.7 f o u r types o f stretch in g can be p e r­ form ed;8 ballistic (b o u n cin g an d jerky) passive (the stretch is p erfo rm ed w ith th e assistance o f an o th er person) con tract-relax (an isom etric m uscle con­ traction precedes th e stretch ) and static. ballistic t h is stretch is p erfo rm ed w ith jerky, bouncing type m ovem ents. h ow ever -------------------------------------------------------------— 17 s p o r t s g e n e e s k u n d e vol. 5 n r . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) soccer • a ssum e th e stretch ed position slowly. • m aintain the position for 30 60 seconds. c hange sides. r epeat two to three tim es. • a lternate m uscle g roups i.e. stretch the arm m uscles, then the leg m u s­ cles followed by the tru n k m u scu la­ ture. • feel a stre tc h , not a pain. • n ever bounce d u rin g stretch as this causes the m uscle to contract w hilst being stretch ed and th ereb y p red is­ poses the m uscle to tearing. • avoid high risk exercise e.g. neck circling, d o u b le straight leg raising, full sit ups (only sit u p to about 45 degrees) and straight leg sit ups (al­ ways ben d yo u r knees). inju ries d isru p t the team , hence the team s perfo rm an ce can be affected. if these few sim ple guidelines are fol­ low ed, a great n u m b e r o f injuries can be prev en ted . r em em ber, it is not only necessary to w arm u p and stretch before p ractice, b ut also before a m atch. due to this b o u n c in g , a great deal o f te n ­ sion is p ro d u ced in the m u scle, and stretching the m uscle against this am ount o f ten sio n , increases the risk of in jury to the m uscle. f o r this reason ballistic stretch in g is not recom m ended. c ontract-relax t h is tech n iq u e com bines an isom etric contraction w ith a stretch i.e. the m u s­ cle to be stretch ed is co n tracted isome trically for 5 to 10 seconds before being stretched. t h e p ro b lem w ith this tech ­ nique is th a t, n ot only does it req u ire a partner, b u t also a great deal o f skill, and therefore is easy to p erfo rm incorrectly. passive in this type o f stre tc h in g , a p a rtn e r a p ­ plies additional p ressu re to the area b e ­ ing stretch ed , th ereb y increasing the am o u n t o f stretch on the m uscle. h o w ­ ever as the player h im self is not co n tro l­ ling the degree o f stre tc h , it is easy to overstretch the m uscle. static t h is m ethod o f stretch in g allows the player to obtain the stretch ed position slowly, and once in this p osition, the stretch is m ain tain ed for a period of tim e. t h is tech n iq u e p ro d u ces the least am ount o f tension in the m uscle, and is therefore the safest m eth o d o f stre tc h ­ ing. s tretching can also resu lt in inju ry if perfo rm ed incorrectly. a few guidelines are detailed below , the p u rp o se o f w hich is to h ighlight the m ost im p o rtan t factors that should be consid ered w hen stretching. • always w arm u p before. • d evelop a safe and effective ro u tin e, based on the needs of the gam e. • s tretch th ro u g h o u t th e season, b e­ fore and after a train in g sessio n . • s tretch before and after every 9 m atch. n o te : a stretching programme is avail­ able from most leading physiotherapists or medical practitioners. figure 1 serves only as a guideline o f stretches, and a vast number o f alternate stretches can also be performed. references 1. conrad d , sidaway r and w ilson b. world cup ’78 the game o f the century. fontana publishers u .k . 1978, 12-15. 2. surve i, r anchod j and kettles an. soccer injuries. s a journal o f sports medicine 2: 12-14,1987. 3. surve i, ranchod j and kettles an. soccer injuries. s a journal o f sports medicine 2: 4-6,1987. 4. sheelock fg. physiological benefits of warm up. physsportsmed. 5. m urphy p. warm up before stretching. let­ ter in phys sponsmed. 6. casperson p. groin and h am string injuries. athletic training 17: 43-45, 1982. 14: 45, 1986.11: 134-138,1983. 7. shellock fg , prentice w e. warm up and stretching for im proved perform ance and prevention of sports related injuries. sports m edicine!: 267-278, 1985. beaulieu je. developing a stretching pro ­ gramm e. physsportsmed9\ 59-66, 1981. anderson b. stretching. shelter publications usa. 1980,118-139. 18 ----------------------------------------------------------s p o r t s m e d i c i n e vol. 5 n o . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) will give you >̂ ,v. more freedom to walk, jump, run and work r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) soccer 20seconds each leg touch chin on chest 60 seconds 30 seconds 25seconds each side 20seconds each leg 10seconds each leg hip m uscle achilles tendon back muscle ankle m uscles 10 times each direction 30seconds inner thigh 20 seconds touch e a r onto th e ground 20 ----------------------------------------------------------s p o r t s m e d i c i n e vol. 5 n o . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) soccer back muscles 8-10 times quadriceps (front of thigh) 20seconds ankle 30seconds each leg shoulder m uscles 10seconds each side 30 seconds each leg hamstrings 1 6 , l 7 a n d 1 8 a ll stretch th e arm and shoulder m usculature 15seconds 10 seconds each arm back m uscles 3 times 5 seconds r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasma update d aw ie van velden fims w o r l d c o n g r e s s o f spo rts m e d ic in e 27 m a y 1 j u n e 1990 t h e 24th fim s w orld c o n g ress o f s ports m edicine held in a m sterd am , th e n e th e rla n d s, was a very successful scientific m eetin g w ith th e th em e o f s p o rts, m edicine and h e a lth . f im s is th e ab b rev iatio n fo r “ f ed eratio n i n te r ­ n a tio n al de m edicine s p o rtiv e ” th e i n ­ te rn a tio n a l s ports m edicine f e d e r­ atio n . t h e o rg a n iz a tio n was fo u n d ed in 1928, and to d a y fim s is a w o rld w ide o rg a n iz a tio n w ith 83 m e m b e r n ations. t h is con g ress was a tte n d e d by fo u r m em b ers o f th e s o u th a frican sports m edicine a sso ciatio n . t h e th ree areas o f scientific e n d e a v o u r in te rtw in e d in sp o rts m edicine, n am ely sports, m edicine and h e a lth , w ere discussed fro m th e s ta n d p o in t o f card io lo g y and related in te rn a l diseases, o rth o p a e d ic s, p h y sio lo g y and biom echanics and the b eh av io u ral sciences. t h e relatio n s b e ­ tw een s p o rt and m edicine as w ell as s p o rt and h e alth w ere addressed in a w ell balanced p ro g ra m m e b y speakers fro m all o v er th e w o rld . sports m edicine, as a fast g ro w in g b ran ch of m edicine needs a solid scientific basis and well d eveloped in te rn a tio n a l c o m ­ m u n icatio n . it was o u r o p in io n th a t the con g ress w ill be rem em b ered as a d e fin ­ ite step fo rw a rd in reaching these goals. t h e secretary general of fim s, p ro f d e d u a rd o h e n riq u e de r ose from b razil, inv ited th e s outh a frican s ports m edicine a sso ciatio n , to app ly fo r af­ filiate m em b ersh ip . a fte r all these years o f iso la tio n , it is e n co u rag in g to see the w o rld w id e change in a ttitu d e n o t only to w a rd s th e “n e w s o u th a fric a ”, b u t to all the c o u n trie s o f th e w o rld , including th e so-called e ast b lock co u n tries. a h an d o f frien d sh ip is extended to a w o rld th a t has g ro w n sick and tired of w arfare. t h is congress p ro v ed to be a w orld f o ru m fo r th e p re se n ta tio n and discu ssio n o f advances and fu tu re tre n d s in sp o rts m edicine. we sincerely h o p e th a t fim s w ill be able to accept o u r in v ita tio n to attend o u r fo rth -c o m in g in te rn a tio n a l sports m edicine c o n g ress scheduled fo r 24-27 a p ril 1991 in sun c ity, b o p u th a tsw ana. t h re e s o u th a fricans p a rticip ated in th e scientific p ro g ra m m e , nam ely d r m artin schw ellnus, d r stinus b arnard and m rs a w enham . we are su re th a t s o u th a frica w ill be able to send a big­ ger c o n tin g e n t to th e next fim s c o n ­ gress sch ed u led fo r 1994 in a th en s, g reece. r e p o r t o n the c o m b in e d sa a ssp e r /sa sm a c o n g r e s s 27-29 j u n e 1990 t h e s o u th a frican a sso ciatio n for s p o rts, science, physical e d u catio n and r ecreatio n (sa a ssper ) held their n a tio n a l s y m p o siu m on w ell-being b e y o n d 2000 in c o lla b o ra tio n w ith the r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasma update s o u th a frican s ports m edicine a sso ci­ ation (sa sm a ) in p o rt e lizab eth on 27-29 j une 1990. h ie rd ie g esam entlike aanbieding kan as ’n baie geslaagde o n d e rn e m in g be skou w o rd , aangesien daar soveel areas van o o rv leu elin g is tu ssen sp o rtg e n e e s­ k u n d e en s p o rtw e te n sk a p . t y d e n s h ie r­ die k o n g res w as d aar ’n g ro o t b y d rae van fisio terap ie gew ees, w at u itstek en d aangevul was m et die o n d e rh o u d e n d e en leersam e in sette van g rah am sm ith, b ek en d e fisio te ra p e u t van g lasgow , engeland. d ie spo rtg en eesk u n d esessies was baie goed b y g e w o o n d e u r alle k o n g res gangers. temas w at g ro o t belangstelling u itg elo k h e t w as ch ro n iese siektes, ch ro n iese lae ru g p y n , ru g b y b eserin g s en o o rg eb ru ik b e se rin g s. o n s is daarvan o o rtu ig dat h ierd ie k o n g res ’n gesonde fo ru m geskep h e t vir alle belangheb bendes in s p o rt om kennis in te w in vir die v o o rk o m in g , b eh an d elin g en reha bilitasie van s p o rten o efen v erw an te pro b lem e. o n e o f th e hig h lig h ts o f this congress was th e p resence o f p ro f n iel o ld rid g e o f the u s a , th e p resid en t o f the a m erican c ollege o f s ports m edicine (a c sm ). n o t o n ly d id he c o n trib u te greatly to th e scientific p re se n ta tio n s, b u t he also discussed his view s on the fu tu re o f s p o rts m edicine in a m erica. being a fo rm e r s o u th a frican and grad u ate from r h o d es u niversity, he has th o ro u g h u n d e rsta n d in g o f o u r country. t h e re cen t p ositive changes in o u r c o u n try have m ade it p ossible to ar­ range b igger in te rn a tio n a l congresses. we are c u rre n tly lo o k in g at the p o ssi­ bility o f h o ld in g th e fo rth c o m in g c o n ­ gress sch ed u led fo r 24-27 a p ril 1990 at sun c ity, b o p u th a tsw a n a in co lla b o ra ­ tion w ith th e a c s m (a m erican c ollege o f s ports m edicine). t h is will surpass o u r p rev io u s con g ress in c ap e tow n in in te rn a tio n a l p a rtic ip a tio n , because it will create th e o p p o rtu n ity fo r m any scientists to com e to s o u th ern a frica. w ith th e c u rre n t fav o u rab le exchange rate fo r foreig n ers, s outh a frica has be­ com e a m ajo r to u ris t attra c tio n as a congress venue! t h is congress w as th e biggest and m o st successful sa a ssper congress ever, and w as m ade p ossible b y a very generous sp o n so rsh ip fro m t r a n s n e t . t h e delegates w ere also e n te r­ tained on a very relaxing and in teresting social p ro g ra m m e , w hich included an u n fo rg e tta b le trip on th e a p p le train. w h o w ill nev er fo rg e t th e icy rain and w ind w e had to face d u rin g this ride to l oerie station! it is also o f h isto rical in te re st th a t a p rev io u s sa a sspe r congress held in p o rt e lizab eth ten years ago, w as o r ­ ganised b y th e c u rre n t p re sid e n t o f the s o u th a frican s p o rts m edicine a ssoci­ atio n . t h is was th e first congress w here a fo ru m w as created fo r delegates from th e m edical and n o n m edical p r o ­ fessions to discuss m atters o f m utual in terest. t h e th em e w as th e use o f exer­ cise as th e ra p y fo r v ario u s diseases and health related p ro b le m s. it is th u s very a p p ro p ria te th a t this excellent congress sh o u ld be th e c u lm in a tio n o f o u r efforts to ack n o w led g e th e m ulti d isciplinary a p p ro a c h to s p o rt exercise and health. t h e o rg an isers m u st be c o n g ratu lated on this very in fo rm ativ e congress. a n n o u n c e m e n t o f t h e f o u r t h n a t io n a l spo rts m e d ic in e c o n g r e s s t h e 4 th n a tio n a l s p o rts m edicine c o n ­ gress is scheduled fo r 24-27 a p ril 1990 in sun c ity, b o p u th atsw an a. o u r th em e fo r th is congress will be r e h a ­ b i l i t a t i o n , and is held in close co l­ la b o ra tio n w ith th e p h y sio th e ra p y c o n g re ss, sch ed u led fo r 22-25 a pril 1991 in p re to ria . t h e first a n n o u n c e m e n t o f this c o n ­ gress will so o n be released. it is envis­ aged th a t we will a ttra c t great in te r­ natio n al p a rtic ip a tio n . r eh ab ilitatio n th ro u g h s p o rt and exercise has becom e increasin g ly im p o rta n t in the medical w o rld , and has w ide app licatio n s in the field o f th e health related sciences. it w ill be w o rth w h ile to diarize these d ates on n ex t years calender. t h is c o n ­ gress w ill be o n e o f th e m o st interesting scientific m eetings on the academ ic cal­ e n d e r fo r s o u th ern a frica. ‘tilcotil’ roche components: tenoxicam indications: s ym ptom atic treatm ent of the fo llo w in g painful infla m m a to ry and degenerative disorders of the m usculoskeletal system : rheum atoid a rthritis; o steoarthritis; ankylosing sp o n d ylitis; extra a rticular disorders, e.g. te n d in itis, bu rsitis, p e ria rth ritis, gouty arth ritis (fo r tablets). dosage: 20 mg once daily at the same tim e each day. the parenteral fo rm is used fo r one or tw o days. for treatm ent in itia tio n in acute gouty a rth ritis 40 mg (2 tablets) once daily fo r two days follow ed by 20 mg once daily fo r a fu rth e r five days is recom m ended. contra-indications: known h yp ersensitivity to the drug. patients in w hom salicylates or other nonsteroidal a n ti­ infla m m a to ry drugs (nsaids) induce sym p to m s of asthm a, rh in itis or urticaria. patients who are suffering o r have suffered from severe diseases of the upper gastrointestinal tract, including g a stritis, gastric and duodenal ulcer. before anaesthesia or surgery, ‘tilcotil’ should not be given to patients at risk of kidney failure, o r to patients w ith increased risk of bleeding. c oncurrent treatm en t w ith salicylates or other nsaids should be avoided. pregnancy and lactation. precautions: sim ultaneous treatm ent w ith anticoagulants a nd/or oral antidiabetics should be avoided unless the patient can be closely m onitored. renal fu n ctio n (bun, creatinine, developm ent of oedema, w eight gain, etc.) should be m onitored, when giving a nsaid to the elderly o r to patients w ith co n d itio n s that could increase th e ir risk of developing renal failure. packs: tablets 20 mg: 1 0 's , 3 0 ’s. vial pack containing 1 vial active substance and 1 am poule w ater fo r injection. -------------------------------------------------------------------23 s p o r t s g e n e e s k u n d e vol. 5 n r . 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) po box 13206 club view 0014 february 1990 dear doctor, the characteristic that distinguishes a professional from an educated person is the professional person's desire and responsibility to stay abreast of the developments of his or her field of expertise. the halflife of our professional knowledge is about 3 years, and for this reason it is vitally important to continuously refresh and supplement our knowledge. sports medicine, the official mouthpiece of the sa sports medicine association, has over the years become a treasured source of knowledge for the health care professional in the sports medicine arena. the journal features not only original research papers and articles by leading specialists in sports medicine, but also current news and relevant abstracts. the publishing of sports medicine has been taken over by medpharm publications. the journal will be published quarterly namely, february, may, august and november. due to the present rate of inflation sasma are no longer able to distribute sports medicine free of charge and have reluctantly introduced a subscription fee of r20.00 per annum (members of sasma will continue to receive the publication free of charge). in addition to managing costs, this will enable the editorial board maintain a high quality editorial content and render a more effective service to you, the health care professional. your subscription to sports medicine is an investment in your future and the future of the health care profession. we count on your continued support. regards, clive noble editor sports medicine x 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sports medicine note * full membership: medical practitioner who is a member of masa ** associate membership: members of supplementary health service professions, registered with the samdc and who are members of their own professional associations • * * student membership: medical students who are in their clinical years r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s o u t h a f r i c a n j o u r n a l o f sports medicine sportgeneeskunde j o u r n a l o f t h e s.a . s p o r t s m e d i c i n e a s s o c ia t io n t y d s k r if v a n d ie s.a. s p o r t g e n e e s k u n d e -v e r e n ig in g n a tio n a l a d v iso ry b o a rd e d ito r in c hief: c live n oble a sso cia te e d itors: p r o f i d n oakes d a w ie van velden a d visory b oard: traumatology: etienne hugo physiotherapy: jo yce m orton nutrition: m ieke f aber biokinetics: m artin schwellnuss epidem iology: d erek yach radiology: alan scher pharmacology: john straughan physical education: hannes b otha internal m edicine: f rancois r e lie f in tern a tio n a l a d v iso ry b oard l yle j m icheli associate clinical professor o f orthopaedic surgery boston, u sa c h ester r k yle research director, sports equipment research a ssociates california, u sa p r o f h c w ild o r h ollm ann president des d eutschen sportarztebundes k oln, w est germany h o w a rd j green professor, department o f k inesiology ontario, canada g eorge a brooks professor, department o f physical education california, u sa n eil f g ordon director, exercise p h ysiology texas, u sa edm und r burke a ssociate professor, b io lo g y department, u niversity o f colorado colorado, u sa g raham n smith p hysiologist g lasgow , scotland v o l u m e 7 n u m b e r 1 fe b /m a r c h 1992 contents editorial comment health care for the future sportsmen o f south africa ........................................................................ 3 cricket cricket injuries w hile on tour with the south african team in india c smith ......................... 4 physiology notes n otes on muscle spindles m frescura ........... 9 nutrition macro-nutrient intake o f various athletes as reported in the literature m faber ................. 11 physiotherapy a review o f the mcconnell approach to the management o f patellofemoral pain j morton .................................................................. 17 restriction o f ankle and foot movements using the standard elastic ankle guard 1 seels, j begley, f futcher and j m itchell ................. 20 news sasm a n ew s .................................................. 25 j o u r n a l o f t h e s o ut h african sports m e d ic in e association 2 6 9 w e s t a v e n u e h e n n o p s m e r e v e r w o e r d b u r g , 0 1 5 7 sasma photographs courtesty o f the image bank t h e j o u rn a l o f th e s a s p o r ts m e d ic in e a s s o c ia tio n is p u b lis h e d b y m e d p h a r m p u b lic a tio n s , 3 rd f lo o r n o o d h u lp lig a c e n t r e , 2 0 4 b h f v e rw o e r d d riv e , r a n d b u r g 2 1 9 4 . p o b o x 1 0 0 4 , c ra m e r v ie w 2 0 6 0 . t e l: (0 1 1 ) 7 8 7 4 9 8 1 /9 . t h e v ie w s e x p re s s e d in th is p u b lic a tio n a re th o s e o f th e a u th o rs a n d n o t n e c e s s a rily th o se o f th e p u b lis h e rs . printed by the natal witness printing and publishing company (ply) lid r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m e d ic a l e r t speaks for you when you cannot 49$ medic alert for more information, contact your doctor or pharmacist ® # a project of the lions of southern africa parke-dav r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) edito rial health care for the future sportsmen of south africa in o rd er to m ake progress in any field o f m edicine, research at both clinical and scientific levels is necessary. sports m edicine is in the sam e situation. often established techniques have to be dis­ carded as new er ones take their place. ideas becom e out-m oded because careful clinical o r scientific investigation shows that they are inco rrect. u nfortunately, the new er in­ vestigations are often expensive and in the south a frican context, they may be too e x ­ pensive for the general public. f o r exam ple, m agnetic resonance im ­ aging (m r i) is utilised worldwide (in the developed countries) as an accurate d ia g ­ nostic tool in most parts o f the body. this investigation costs in excess o f r1 000 in south a frica. but it may be necessary, e .g . using the mri scan it has been shown that in anterior cru ciate ligam ent tears o f the knee jo in t, bone on the low er end o f the fem ur may also be dam aged. r etrospectively arthroscopic surgery, in itself an expensive technique, has been shown to m ake diagnoses of internal d e­ rangem ents o f the knee with far g reater a c ­ curacy than before. n ot only this but surgical treatm ent through the arthroscope has m arkedly reduced the incidence o f o steoarthritic dam age to the jo in t caused by previous open surgical techniques. this will cause a trem endous reduction in long term m orbidity and the possibility o f having an expensive total knee replacem ent in the future. at the present stage m ore and m ore black athletes are jo in in g m edical aids and will be able to afford first w orld m edicine. n ew er legislation may well greatly increase this num ber. o bviously the level o f good health care for all sportsm en is the most desirable but unfortunately the cham pions are in an elitist category and may well req u ire a higher level o f m edical skills and investigations. t h ere is no w ay, for exam ple, that a top class sportsm an with a torn m eniscus can and should have to w ait for a hospital bed as is the situation in state social m edicine which often happens at the present stage. t he future holds interesting prospects for sportsm en and sports m edicine. dr c live n oble, m bbchb, fcs (sa). e d ito r-in -c h ief -------------------------------------------------------------------------- 3 spo rtg eneesku n de vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket cricket injuries while on tour with the south african team in india c smith keyw ords: international tour, cricket injuries, physiotherapy. abstract this paper briefly discusses the injuries encountered and their management during the south african cricket team's inaugural 8 day tour o f india in november 1991. the team consisted o f a squad o f 14 players and the team physiotherapist. the tour marked the return o f south africa to the international cricket arena after 21 years o f isolation. the most commonly injured area was the lower limb (64%) with the bone/ joint structures accounting for 7 (50%) o f the injuries. continued research and interest in this field will contribute towards a better understanding and management o f cricket related injuries. in t r o d u c t io n cricket is a sport which is widely played throughout this country and the world, yet un­ like running, cycling, sw im ­ ming or rugby, little research has been done on the varied aspects o f the game. however, the last few years has demon­ strated a growth o f interest in cricket which has specifically resulted in a recent spurt o f local paper publications. the specific areas looked at include the injuries related to cric­ ket, ‘•2-3 injuries associated with cricket tours,1 the comcraig smith, bsc physiotherapy, bsc (med) (hons) sports science. uct sports injuries clinic, university o f cape town. plex motor skills o f the crick­ eter (batsman)4 and anthro­ pometric profile and body com ­ position o f cricketers.5-6 a fair amount o f other published material on cricket injuries al­ ready exists in the literature, mostly eminating from aus­ tralia.7'12 even so, very little data has been captured on cri­ cket injuries associated with touring teams with only one publication known to be re­ ported on this top ic.1 hopefully, this is changing in south africa, as its cricket o fficia ls have cham pioned south africa's return to the international arena with full membership status in the in­ ternational cricket council. this now means that south africa can embark on tours to other countries and play host to touring countries, increasing the exposure o f its players to international competition. this will in turn have the effect o f further increasing the opportu­ nity to investigate the area o f injuries associated with tou­ ring international teams, as the research on cricket injuries in south africa has, up till now, been confined to domestic lev el.4 the purpose o f this brief paper is thus to report on the injuries which were en­ countered during the south african cricket team 's inau­ gural 8 day tour to india during novem ber 1991 and to form a base for further data collection and research on cricket injuries in this country. b a c k g r o u n d within a day o f deciding that the south african cricket team was to tour india for 3 one-day intema-tionals, the author was informed that he was to tour with the team as physiother4 --------------------------------spo rts m e dic in e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket give them a sporting chance against pain apist. the next two days were spent at high speed organising equip­ ment and making necessary arrange­ m ents b efo re the team met together for the first tim e. o nly one practice was possible before departing for india. on arrival in c alcutta, the first stop, the team had tw o days to recover, ad ju st to the culture shock, acclim atise and practise b efo re the first test m atch. in all, 3 one-day test m atches w ere played with rest days inbetw een each match. n one o f the players presented with any injuries w hich may have prevented them from playing the first match. b efore each p ractice session and m atch, the squad w ent through a w arm -up period o f jo g g in g , arm loosening exercises and stretching to m ain-tain o r im prove their flex i­ bility and p revent fu rth er injury. all the players w ere active p artici­ pants in their provincial cricket p ro ­ gram m es and thus did not require any form o f exercise to im prove their state o f fitness. in ju r ie s a nd t r e a t m e n t s f o r the purposes o f this paper, an injury w as defined as any condition which required physiotherapy or medical treatm ent. eight o f the players received treatm ent w hile 6 players did not. t he coach received treatm ent for his shoulder which had been operated on a w eek prior to dep artu re (not included in the data). t h ere w ere a total o f 14 separate injuries w hich required treatm ent. d ividing the injuries into anatom ical areas, 64% w ere to the low er lim bs, 14% to the upper lim bs, 14% to the head and neck and 7% to the tru n k and back. t h ere w ere 7 b o n e/jo in t injuries, 3 involving tendons, 1 m uscle injury, 1 ligam ent injury and 2 soft tissue injuries (bursitis and haem atom a). f o u r injuries occurred w hile batspo rtg e n e esku n d e vol. 7 no. 1 5 in soft tissue in ju rie s ... froben loo helps restore e a rly patien t m obility # convenient 15 tablet, 5 d a y a c t io n pack # suitable for competitive sportsmen and women # effectively relieves pain # effectively relieves swelling # peripheral action avoids injury abuse in sport rx froben 100 t.d.s. also available in suppositories. boots p h a r m a c e l't ic a ls (pty) ltd 4 0 electron avenue, isando 1 6 0 0 your gam e plan agalnsf pain flu rb ipr ofe n 10 0m g r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket t a b le 1: anatom ical injury profile anatomical site head and neck (14%) 2 upper limbs (14%) hand 1 fingers 1 trunk and back (7%) 1 lower limb (64%) hip 4 thigh 1 knee 2 lower leg 1 ankle 1 total 14 injured structures bones/joints 7 muscles 1 tendons 3 ligaments 1 soft tissue 2 total 14 ting, 4 as a result o f bow ling and 6 while fielding. one player w as treated for 5 separate injuries, three players for 2 in­ ju rie s , and 5 players fo r a single injury. o nly 1 injury was considered a major injury which prevented the p layer from playing again on the tour. t he m ost com m on site in­ ju re d w as the hip region w here 4 injuries occurred. one-player developed a m inor psoas b u r­ sitis w hich w as treated with ice, ultrasound and laser. h e did not request any further treatm en t fo r this injury as he could play again w ithout pain. t he o th er hip injuries involved tw o players during the last g am e, o n e straining his right psoas tendon and left rectus fem oris tendon and the o th er p layer his rig h t rectus fem oris tendon. t w o reasons exist to ex ­ plain the cause o f these inju­ ries. f irstly , both p lay er had o th er m inor injuries involving the sam e lim b. t h ese injuries m ay h a v e s u b c o n s c io u s ly caused the players to co m p en ­ sate fo r the use o f th eir injured m uscles by overex ertin g and straining supplem entary m us­ cles o f the sam e lim b. t he second reason is that the venue for the final gam e w as an ath ­ letics stadium w hich included a tartan running track w ithin the field o f play. t h ese two p la y ­ ers fielded near to the boundary for m ost o f the gam e and thus had to, at tim es, field the ball by running on the tartan track. it is proposed that the activity o f having to quickly start ru n ­ ning and then stop to field the ball as well as changing d irec­ tion w hile using spiked cricket boots on the tartan track may have lead to the hip injuries involving the psoas and rectus fem oris tendinous insertion sites. t w o hand injuries w ere o b ­ served. o ne p lay er received a blow with the crick et ball to his right hand w hile batting, re ­ sulting in an undisplaced crack fracture o f the base o f the sec­ ond m etacarpal bone. he w as forced to w ithdraw from the team for the final gam e and his hand w as strapped for the duration o f the to u r and treated daily w ith ice, laser and an al­ gesics when required. t he o th er p lay er w hose position involved much catching o f the ball sprained the distal inter phalangeal jo in t o f the little finger. his function in the team necessitated that he play all gam es and he w as treated w ith ice, jo in t m obilisations, laser and ultrasound. t w o p la y e rs d ev elo p ed sym ptom s arising from the cervical spine. o ne complained o f unilateral headaches with retro and supero-orbital eye pain. this w as treated with m obilisations to the u pper cer­ vical spine and acupressure to relieve pain and tension in the surrounding m uscles. t he sym ptom s w ere com pletely relieved a fter 2 days. t he other p lay er flared up a troublesom e cervical spine injury which had plagued him fo r a few years. h is injury w as related to his bow ling technique w here upon d elivery o f the ball he w ould thrust his neck from the neutral position to right side flexion and then sharply back to left side flexion when re ­ leasing the ball. he ex p eri­ enced pain and tension in the trapezii, levator scapulae and rhom boides m uscles and which w as also aggravated by po o r sleeping posture. he too re­ sponded favourably to spinal m obilisations and soft tissue acupressure. one o f the bowlers presented w ith a history o f mild scheur m ann's disease and complained o f lum bar disco m fo rt, stiffness and tension in his low back m uscles. h e w as treated reg u ­ larly w ith soft tissue m assage and acu p ressu re to relieve the m uscle tension, spinal m obili­ sations and ultrasound. e m ­ phasis was also placed on warm­ up back exercises before he 6 -----------------------------------spo rts m e dic in e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket give them a sporting chance against pain bow led and stretching his ham string m uscles. t w o players had injuries in vol­ ving the knee jo in t. one player received a blow with the ball through the pro tectiv e padding to the patella fem oral jo in t w hile the other had a grade 1 m edial collateral ligam ent sprain. both responded well to treatm ent. o ne p layer was struck on the ankle w ith the cricket ball resulting in periosteal and su­ p erficial soft tissue bruising. he was treated with ice, ultrasound and laser therapy. a nother player sustained a slight strain to his calf m uscle w hich w as treated with cross-friction m assage, ultrasound and laser stim ulation. f inally, one o ther p lay er was struck on the thigh through his padding leading to a superficial haem atom a. this too was treated with ice, ultrasound and laser. d is c u s s io n t he injuries associated with the south a frican crick et team s' inau­ gural 8 day to u r to india have been presented. a total o f 14 injuries w ere encountered w ith only eight o f the players requiring treatm ent. a lthough the to u r was b rief in d u ra­ tion, these injuries need to be re­ ported to supplem ent the already existing, yet lim ited data on cricket injuries. in com parison with o ther tours o f sim ilar nature, the num ber o f injuries appear to be quite low . on a previous to u r o f 5 weeks to this c o u n try ,1 a total o f 40 injuries w ere incurred at an incidence o f 2,5 in­ ju re s per player. this tour enco u n ­ tered 14 separate injuries at an incidence o f 1 injury per player. this statistic seem s to be a lot low er than the previously documented tour, yet if the incidence o f injury on the previous tour is assessed for only those players w ho w ere injured, then it appears clo ser at 1,8 per spo r tg e n e esku n d e vol 7 no. 1 in soft tissue in ju rie s ... froben 100 helps restore e a rly patien t m obility # convenient 15 tablet, 5 d a y a c t io n pack # suitable for competitive sportsmen and wom en % effectively relieves pain % effectively relieves swelling # peripheral action avoids injury abuse in sport rx froben loot.d.s. also available in suppositories. a k boots i'hakm al'kl t il'a i.s ipty) ltd 4 0 electron avenue, isondo 1 6 0 0 your gam e plan against pain flu rb ipr ofe n 10 0m g r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cricket t a b le 2: physiotherapy treatment m odalities players treated 8 t reatments given 31 treatment modalities electrical: interferential 1 ultrasound 9 laser 9 total 19 manual: mobilisations peripheral joints 8 spinal joints 6 massage non-specific 5 cross-frictions 2 acupressure 10 total 31 strapping 5 ice 14 exercises 3 injections (voltaren) 2 total 24 total treatment modalities 74 player. t h e o th e r p o int which needs to be considered is that this to u r w as alm ost one fifth the duration o f the previous tour and only 3 m atches in total w ere played. t ab le 1 show s that the inci­ dence o f injury was found to be greatest in the low er limb (64% ) follow ed by the head and neck (14% ) and the upper lim b (14% ). t h e trunk and back w ere least involved co n ­ tributing only 7% o f the in ju ­ ries. t h e prev io u s crick et to u r1 dem onstrated sim ilar results w ith m ost injuries occu rrin g in the lo w er lim b (4 6 % ), follow ed by the u pper lim b (2 7 % ), the back and trunk (19% ) and the head and neck m aking up 8% o f the injuries. s tre tc h 's 3 data on cricket injuries appears slightly d iffe r­ ent and m ore evenly spread, as he show ed that in serious inju­ ries during the dom estic sea­ son, 30% w ere to the low er lim bs, 32% to the upper lim bs, 20% to the head and 18 % to the back and trunk. t h ese figures w ere slightly varied for less serious injuries with 27% to the low er lim bs, 43% to the upper lim bs, 16% to the head and 14% to the back and trunk. w hat can be inferred from these figures is that the inci­ dence o f injury to the d ifferent areas o f the body encountered during dom estic cricket and w hile on tour may d iffer quite considerably and thus special preparation should be m ade for this. t hese results also suggest the need for specific and in d i­ vidualised pro g ram m es to be prepared for each player during the off-season and before em ­ barking on international tours o f any nature. batting and bow ling each accounted for 29% o f the inju­ ries with fielding m aking up the rem ainder (43% ). t hese figures com pared with the p re ­ viously reported to u r 's unpub­ lished d a ta ,1 show ing that 25% o f the injuries resulted from batting, 39% bow ling and 36% fielding. t he study on cricket injuries during the dom estic season3 found that 42% o f inju­ ries occurred while batting, 33% w h ile b o w lin g , w h ile o n ly 19% from fielding. f o r the 8 players treated, 31 treatm ents w ere given using 74 treatm ent m odalities (table 2). t he m ost com m on m odali­ ties given w ere those involving manual treatm ent techniques, follow ed by electrical m odali­ ties, ice and then strapping p rocedures. c o n c l u sio n as crick et in o u r country can now only go from strength to strength, it is hoped that this data will co n trib u te tow ards the scientific pool o f evidence that already exists regarding the gam e. i f the standard o f crick et is to be m aintained and im proved, then so too must the input from research support this philosophy. t h e physical dem ands o f the gam e and the unnecessary injuries w hich are so often suffered need to be m inim ised, especially when com peting for ones country at international level. t his can be achieved through p lay er and coach education, as well as the m edical m anagem ent team keeping abreast with the latest scientific trends and in fo rm a­ tion. h opefully this short paper will add to the already existing know ledge and also rem ind us not to forget that "the m essage o f m odern sport is that you ignore science at yo u r own p e ril" .4 □ references on request. 8 -------------------------------------spo r ts m e dic in e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiology notes notes on muscle spindles m f re sc u ra figure 1: schematic diagram o f muscle showing a muscle spindle and nerve pathways to and from the central nervous system (cns). did you ev er think that v olun­ tary m uscular m ovem ents are driven by a servom echanism sim ilar in m any respects to the au tom atic feedback system em ployed to control pow er assisted steering in a c a r? 1 i shall en d eav o u r in this article to dem o n strate such a view point through a b rie f discus­ sion o f the role o f muscle spindles. m uscle spindles are m uscle sense organs located am ongst the fibres o f a m uscle with an im portant role in controlling m uscular m ovem ent. t hey are com posed o f long thin bundles o f m odified m uscle fibres with sensory nerve endings attached to a non-contractile central region. s pindles and main m uscle fibres are in n er­ vated by independent m otor nerve fibres (f ig u re 1). t h e sensory endings o f the specialised central region are excited by being stretched. stretching initiates a d is­ ch arg e o f nerve im pulses to the central nervous system which produces an autom atic co n ­ traction in the main m uscle a m frescura medical researcher mrc po box 19070 tygerberg 7505. stretch reflex. t he spindle can be stretched either by a stretch in the main muscle as when an ex tra load is im posed on a m uscle already bearing a w eight (f igure 2) o r by a co n ­ traction o f the contractile com ponent o f the spindle (f ig ­ ure 3). t he stretch reflex m echanism will cause the main m uscle to adjust its contraction appropriately. w hen co n trac­ tion o f a spindle is follow ed by a contraction o f the main m uscle, the stretch on the sen­ sory region o f the spindle will be relieved (f ig u re 4) and no fu rth er nerve im pulses will be d ischarged. t h e spindle, in effect, is sensitive to the d if­ ference in length betw een it­ self and the main m uscle fibres. by this sensitivity it behaves as a m isalignm ent d etector for au tom atic com pensation. h um an m uscles, in general, can be shown to be under the influence o f the stretch reflex w henever engaged in steady co n tractio n s o f a voluntary na­ ture. t his invaluable self­ regulating pro p erty o f a m uscle ----------------------------------------------------------------------------- 9 spo r tg e n e esku n d e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiology notes figure 2: a stretched muscle (long arrows) stretches the sen­ sory region o f the spindle dis­ charging a nerve impulse (dotted arrow line). figure 3: contraction o f the contractile spindle ends (short arrows) also stretches the sensory region discharging a nerve im­ pulse (dotted arrow line). figure 4: contraction o f the main muscle (long arrows) relieves the stretch on the spindle (short ar­ rows) silencing the nerve impulse. enables it to adjust au to ­ m atically to changes in load. it is the m uscle spindle sensor, by m onitoring length differentials between itself and the main muscle which confers this subconscious self-regulating pro p erty on o u r m uscles. d uring continuous m ove­ m ent, the spindle contracts at the desired rate so that its sensory endings will only be excited if the main muscle does not keep up with the spindles. c ontraction o f the spindle e f­ fectively drives the main m uscle by m eans o f the stretch reflex which sw itches on m ore contraction if the rate o f short­ ening loses synchrony with the spindle. in sum m ary, the stretch reflex controlled by the spindle is an autom atic feedback re ­ sponse, a follow up serv o ­ m e c h a n is m a n a lo g o u s to pow er-assisted steering in a car. c ontraction o f the spindle corresponds to turning the steering w heels, shortening o f the main m uscle to turning o f the road w heels, with the spindle sensory ending acting as the m isalignm ent detector. a subject can dem and o f his muscles either a certain limb position o r a rate o f change o f limb position and his dem ands will be autom atically met by his m uscle servo. references 1. pa merton. in: readings from scientifice american. freeman: san francisco, 1972. notes on m uscle spindles is the last in a series o f three articles w ritten by m f rescu ra p h d , m edical r esearcher at m r c , t ygerberg. t he first tw o articles in the series w ere titled: 1. n otes on the physiology o f muscle contraction sajsm, volum e 6 , n o 4. 2. isometric and isotonic muscle c o n tr a c tio n s s a j s m , v olum e 6, n o 5. erratum notes on the physiology of muscle contraction sa journal o f sports medicine vol 6 no 4. in the last paragraph of the above m entioned a rticle , th e w o rd "a syn ch ro n o u sly" w as erroneously printed as "s y n c h ro n o u s ly ". w e apologise to our readers and the author. 10 -------------------------------------spo r ts m edicin e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition macro-nutrient intake of various athletes as reported in the literature m ieke f ab er a thletes tend to experim ent with d ifferen t dietary regim es to find the optim um athletic diet. t h ere is how ever, no evidence that such special d ie­ tary regim es im prove p erfo rm ­ ance. d ietary studies have indicated that there is ex trem e variability in the dietary in­ takes o f a th le te s.1'3 van e rp -b aart e t ap stud­ ied the nutrient intake o f v ari­ ous endurance and strength athletes. m ale athletes had a mean energy intake ranging from 12 ,1 -2 4 ,7 m j/day. f e ­ m ale athletes had an energy intake ranging from 6 ,8 -1 2 ,9 m j/day. m ale en durance ath ­ letes had the highest energy intake w hile fem ale strength athletes had the low est energy intake. a protein intake o f 1,2 g /kg body w eight for men and 1,0 g /k g body w eight for w om en is recom m ended. m ost o f the studied athletes fulfilled these recom m endations. c y ­ clists and runners averaged mieke faber research institute fo r nutritional diseases medical research council m ore than 55 % o f the energy as carbohydrates w hile the carb o ­ hydrate intake o f strength a th ­ letes was as low as 40% e. brotherhood4 has sum m a­ rized the nutrient intake o f athletes as reported by several authors. this sum m ary shows that there is a w ide range o f energy intake betw een athletes. in general they appear to be high energy consum ers, al­ though some o f the energy in­ takes seem to be surprisingly low. e ndurance athletes co n ­ sum e at least 50 k cal/k g /d ay , w hile those involved in in ter­ m ittent o r high pow er activity sp o rts co n su m e less than 50 k cal/k g /d ay . it should h o w ­ ever, be kept in mind that the latter athletes can weigh b e ­ tween 20 and 50% m ore than the endurance ath letes.4 b arr5 sum m arized the nutrient intake o f fem ale athletes and she cam e to the conclusion that fem ale athletes consum e on the average 2069 kcal. b rother­ hood4 sum m arized that athletes consum e approxim ately 16% o f the energy as protein (al­ though in som e cases it w as as high as 3 6 % e), 36% o f the energy as fat and 46% o f the energy as c h o . this is in ag reem en t with the values found by barr5 when she sum ­ m arized the nutrient intake o f fem ale athletes. she found that fem ale athletes consum ed on the average 15% protein, 36% fa ta n d 4 9 % c h o . t h ere w ere , h ow ever, big variations in en­ ergy distribution betw een d if­ ferent ath letes.4 5 w hen repor­ ting nutrient intakes athletes can not be grouped together, but each specific activity group should be studied separately. c y c l ist s in co n trast with the study o f v an e rp-b aart e ta p who found that fem ale cyclists consum ed a high energy diet, another study reported low energy intakes in highly trained fem ale cyclists. this study reported an energy intake o f 85% o f the rda. sixty p ercent o f the energy intake w as supplied by carb o ­ hydrates, 14% by protein and 26% by fat. n orm al album in levels indicated that the p ro ­ tein intake was 1,1 g /k g body w eight in this study w as suffi­ cient to m eet the protein needs o f these a th lete s.6 h igher en ­ ergy intakes o f 26282 kj per day have been reported in m ale cyclists. t hese m ale cyclists w ere shown to have a nibbling eating pattern , characterized ------------------------------------------ 11 sportgeneesku n de v o l 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) n u t m t k o n by frequent eating and drink­ in g .7 bo d y b u il d e r s it has been found that body builders follow a high energy diet.8,9 in the study done by kleiner et ap the mean energy intake o f male body builders was 5739 kcal, with the highest energy intake a very high 19760 kcal. h ow ever, directly prior to a competition body builders cut down on their energy in­ take. the mean energy intake o f males before a competition was 2347 kcal and that o f fe­ males 1535 k ca l.10 although it has been found that body builders consume a high protein diet (as high as 31 % e ) ,8,9,11 a high percentage o f these athletes supplemen­ ted their diets with high protein pow ders.9,12 compared to other athletes with similar en­ ergy intakes, body builders consumed a high protein diet expressed in terms o f g protein per kg body weight. this can be explained by the use o f extra protein supplements.3 before a competition body builders follow a higher protein diet (34% e for males and 26% e for fem ales). for the males and the females respectively, these protein intakes equal 2 ,4 and 2 ,0 gm o f protein per kg body w eig h t.10 it has been stated that body builders fo l­ low an even higher protein in­ take months prior to a com peti­ tion (40-50% o f the energy in­ take).13 conflicting data regarding the fat and cholesterol intake o f body builders has been repor­ ted. w hile baldo-enzi e t a lu reported that these athletes consumed a diet low in fat (less than 30% e ), faber e t ap found that body builders con­ sumed a diet high in fat (up to as high as 46% o f the energy in­ take). before a competition body builders cut down on their fat intake. their fat intake be­ fore a competition was as low as 1 5 %-16% e for men and 1 3 % -14% e for w om en.9,10 this high protein, low fat in­ take was maintained through the consumption o f mostly white chicken meat, lean fish, egg whites and white tuna canned in water. very few body builders consumed red meats or dairy products before a com petition.10 faber e t ap reported that body builders consume a diet high in cholesterol due to a high egg intake (up to as high as 3992 cholesterol mg per day). the maximum cholesterol in­ take o f body builders studied by kleiner e t ap was 9393 mg per day. in contrast with this, baldo-enzi e t a ln reported a much lower cholesterol intake in body builders (477 mg). this low er cholesterol intake was also reported before a competi­ tion .10 b a l l e t d a n c e r s fem ale ballet dancers con­ sumed too little energy. the mean energy intake o f female ballet dancers was 71,6% o f th er d a . an alarming 20% o f the dancers consumed less than 50% o f the r d a .14 these low energy intakes are not only seen in adult dancers, but also in adolescent dancers. a do­ lescent dancers consumed an average o f 350 kcal less each day than is recommended to support normal grow th.15 one third o f dancers reported having eating problems (self reported anorexia nervosa or bulimia).16 dancers believe that carbohydrates are high energy foods. the carbohydrates in their diets are mainly simple rather than com plex carbohy­ drates. 15 ic e sk a t e r s another group o f athletes for whom thinness is a require­ ment, are ice skaters. in a study done on com petitive ice skaters it was found that the fem ale skaters had a very low energy intake (55% o f the r d a ). the low est energy in­ take was a very low 373 kcal per day. forty-eight percent o f the females had eat scores within the anorexic range. these low energy intakes and high eat scores were not found in the male ice skaters, indicating that male and female ice skaters should be studied as separate groups. the author o f this study concludes that this study has shown the need for nutritional education for com petitive ice skaters.17 g y m n a st s another sport where leanness is considered as an essential requisite is gymnastics. not only should she be lean for practical reasons, but also for aesthetic reasons. in order to maintain these lo w body weights young female gymnasts have reported a low energy in­ take o f 1552 k ca l.18 a group o f older gymnasts (mean age 19,2 years) also averaged a low 12 --------------------------------sports medicine vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition energy intake. their mean intake o f 1827 kcal per day did not meet the r d a for energy intake.19 gymnasts have re­ ported to have a low er energy intake than inactive controls, but expressed as kcal/kg body weight there was no difference between the gymnasts and controls.20 their energy dis­ tribution has been reported to be 15,3% e protein, 4 7 ,7 % e cho and 36,0% e fat.18 this kind o f energy distribution was also found in a group o f high school gym nasts.21 the young female gymnasts studied by benardot et ap2 reported a slightly higher carbohydrate intake (approximately 53% e) and a slightly low er fat intake (approximately 32% e). there was however, a w ide variation in cho intake, ranging from 9 7 ,7 to 3 7 7 ,8 g/day. only two o f the gymnasts did not meet the r da for protein. runners runners reported significantly higher total energy intake than sedentary controls. the male runners averaged an energy intake o f 2950 kcal w hile the female runners averaged 2386 kcal per day.23 this range o f energy intake by fem ale run­ ners were also reported by duster et ap4 the leaner run­ ners consumed 40-60% more kcal/kg than the fatter controls. the increased calorie intake by runners appeared to be primar­ ily from fats and carbohydrates, however, expressed in terms o f percentage energy distribu­ tion, there was no difference between the carbohydrate and fat intake o f the runners and the sedentary controls. the run­ ners averaged a fat intake o f 40,8% e (sd = 6 ,7 ) for the males and 41,4% e (s d = 5 ,8 ) for the females. carbohydrate intake expressed in terms o f percentage o f total energy in­ take for the male and female runners were 39,8% e (sd = 7 ,7 ) and 39,5% e (sd = 6,9) respectively.23 these high fat intakes were confirmed by manore et ap5 in female run­ ners, but they found that the female runners had a slightly higher cho intake o f approxi­ mately 50% e. deuster et ap4 reported an even higher cho intake o f 55 % e in highly trained female runners, accompanied by a lower fat intake o f 32 % o f the energy intake. kirsch et av not only confirmed the higher energy intake in runners as compared to sedentary con­ trols, but they also found that cyclists have a higher energy intake than runners. the total energy intake o f the runners and cyclists exceeded the basic metabolic rate o f 103% and 250% respectively. although the study o f nieman et a lli confirmed the higher energy intake in runners (2526 kcal for males and 1868 for females) as compared to the average popu­ lation, these differences were very small, especially for men (4% for men and 16% for w om en). however, their en­ ergy intake fell below the levels recommended by the food and nutrition board for men and women doing light work (2700 and 2000 kcal respectively). energy intake, expressed in terms o f kcal per kg bodyweight increased with an increase in km run per w eek .18 although blair et api as w ell as pate, et ap6 could find no difference in energy distribution between runners and sedentary con­ trols, the study by nieman et alli indicated that runners con­ sumed far less energy as fat and more energy as cho as the general population. the male runners averaged 30,9% e fat and 51,8% e cho w hile the fem ales averaged 32,0% e fat and 52,7% e cho. these low er fat intakes and higher cho intakes by runners were confirmed by a later study.26 cholesterol intake for males as w ell as females fell below the recommended maximum o f 300 mg per d a y .18,26 the cho­ lesterol intake and the intake o f saturated fatty acids o f the runners were much lower than the cholesterol and saturated fatty acid intake o f the average american population.18 w hen asked about the changes that they have made in their diets since they have started running, the runners stated that they consumed more fruits, vegetables, whole grains, poultry and fish and less red meat, eggs, salt and fats.18 the high fibre intake by highly trained runners reflected the consumption o f large quan­ tities o f fruits and vegetables.24 although none o f the runners studied by manore et ap5 were vegetarians they generally consumed less than 3 oz o f meat, fish or poultry per day. in a study done on the feeding patterns o f endurance athletes, it was found that runners showed a nibbling pattern, characterized by frequent eat­ ing and drinking.7 swimmers young fem ale swimmers con­ sumed 21,5% more energy than continued on p a g e 16 ------------------------------------- 13 sportgeneeskunde vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) [s3] relifen 500 tablets 500 m g n a b u m e to n e . reg no r / 3 . 1/265 w h en y o u r p a tie n t’s in pain, y o u r first responsibility is to take aw ay th a t pain. q u ick ly . effectively. b ut doing so could lead to unacceptable gastro­ intestinal side effects and co m b in atio n th erap y . b u t n o w , ten years o f precisely targeted m olecular research have p ro d u c e d a highly effective, n o n-acidic an ti-in flam m ato ry . relifen. each tablet is m ade o f 500 m g n ab u m eto n e , a n o n -stero id a l an ti-in flam m ato ry , p ro v en in n u m e ro u s d o u b le b lind studies to be as effective as o th e r b en ch m ark n s a id s. yet its ro u te o f action is to tally different. relifen is a non -acid ic p ro -d ru g . in the stom ach, it is relatively inactive. it is ab sorbed from th e d u o d e n u m , into the p o rtal b lo o d supply f inally, in th e liver, it is m etabolised into a p o te n t in h ib ito r o f pro stag lan d in synthesis. r e f e r p a c k a g e i n s e r t f o r fu ll p r e s c r i b i n g i n f o r m a t i o n . f u r t h e r i n f o r m a t i o n is a v a il a b le f r o m o u r m e d ic a l d e p a r t m e n t . s m it h k lin e b c e c h a m p h a r m a c e u t i c a l s p o b o x 3 4 7 b e r g v lc i r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) relieving his pain is pretty sporting of you, old chap. but do you have to get him high on acid? t h e active m etab o lite pen etrates th e synovial fluid to reach the inflam ed site, giving effective relief of s \ m ptom s. e xcretion is by th e k id n ey s, so g astro •nti stinal dam age th ro u g h biliary recircu latio n and reflux is unlikely. f o r effective relief from pain and inflam m ation, with less chance o f g astro -in testin al d isco m fo rt, y o u now have an ideal choice. relifen. ^ " " ''i t i n sb l o g o artt r a d e m a r k s . sb b e e c h phar̂ c e u z % * m r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) nutrition sedentary controls. the swim ­ mers consumed 2468 kcal per day.27 this kind o f energy intake was confirmed by a study done by tilgner and sch iller28 w ho found that swimmers consumed 2493 kcal which was also higher than the energy intake o f non-athletes. in a later study however, it was found that swimmers did not have a higher energy intake as compared to inactive controls.20 percentage energy distribution was similar for the swimmers and the controls namely 49 % e to 54% e carbohydrate, 33 to 35% e fat and 12 to 15% e protein.27-28 basketball players m a le b a s k e tb a ll p la y e r s averaged a daily energy intake o f 3558 kcal w hile fem ale bas­ ketball players averaged a daily energy intake o f 1730 kcal. both males and females averaged similar energy distri­ butions. the energy distribu­ tion for the males was 17% e protein, 34% e fat and 48% e cho w hile that o f the females was 16% e protein, 32% e fat and 52% e cho. protein was generally higher than neces­ sary. som e o f the men had very high cholesterol intakes (as high as 1482 mg per day). both men and women had low fibre intake. this reflected the limited consumption o f w h ole grains, fruits and vegetables.29 hockey players field hockey players aver­ aged a daily energy intake o f 1956 kcal. their energy distri­ bution was 15,5% e protein, 46,8% e cho and 38,6% e fat.28 volleyball players the dietary intake o f female high school athletes between the ages o f 13 and 17 was determined. eighty-one per­ cent o f the athletes indicated a concern with their weight, w hile 73% wanted to loose weight. that might be why they averaged a low energy intake o f 1799 kcal (84 % o f the r d a ). their energy intake was lower than other teenage girls in the united states. food consumption analysis showed that o f total servings, the milk and meat groups accounted for only about 10% each and that more than 30% came from the "others" group.30 field athletes one study reported the macro­ nutrient intake o f male field athletes. they averaged an energy intake o f 3528 kcal. they had an energy distribu­ tion o f 13% e protein, 28% e fat and 55% e carbohydrates.1 it should, however, be kept in mind that these field athletes were grouped together with track athletes. it was also not state whether the field ath­ letes were jumpers or throw­ ers. this is important to keep in mind since, although no die­ tary differences have been re­ ported, it was found that these athletes differ in anthropomet­ ric measurements.31 the die­ tary intakes o f throwing field athletes might be more accu­ rately displayed by those val­ ues reviewed by brotherhood (1984). in this review the die­ tary intake o f shotputters (as reviewed by sal tin) and discus throwers (as determined by ward et al) are review ed. the energy intake o f these athletes was higher than that reported by short and short.1 the shotputters averaged an ener­ gy intake o f 4300 kcal w hile the discus throwers averaged an energy intake o f 4663 kcal. w here the track and field ath­ letes as studied by short and short1 consumed a diet that fulfilled the requirements for a prudent diet,32 the throwing field athletes consumed a diet that was high in fat (44% for the shotputters and 40% for the discus throwers) and low in cho (42 % for the shotputters and 39% for the discus throw­ ers). summary it is therefore clear that there is a w ide variation in the macro­ nutrient intake o f athletes. when studying the nutrient intake o f athletes it should always be kept in mind that conflicting results have been reported for som e athletes. it should also be kept in mind that the athletes diet before a com ­ petition may differ from the usual eating pattern. brother­ hood (1984) summarized the nutrient intake o f various ath­ letes and cam e to the overall impression that national die­ tary customs have the pre­ dominant influence on the ath­ letes' diet. he came to. the conclusion that there-is no ev i­ dence that athletes follow a more healthy diet than less active people. □ 16 -------------------------------sports medicine vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy a review of the mcconnell approach to the management of patellofemoral pain joyce morton if one asked a number o f phys­ iotherapists o f the ways in which they treat chondromala­ cia patellae or patellofemoral pain, their answers would be varied from mobilization o f the patella, quadriceps strengthe­ ning exercises either isotonic or isokinetic, faradic stimula­ tion o f the vastus medialis, electrical modalities such as laser and ultrasound, ice or specific m uscle stretching. as the aim o f all physiotherapy treatment for this condition is to achieve a full range and pain free function o f the joint, if any o f the above modalities achieve this, then the aim o f treatment has been meet. h ow ever, if this is not the case and the m cconnell approach is not known to you, then you may find the follow ing o f interest. jenny m cconnell, an aus­ tralian sports physiotherapist, first advertised her approach in the mid 1980's. it has subse­ q u en tly b e c o m e p o p u la r throughout a greater part o f the physiotherapy world. i was amused to discover how much it is used by the british physio­ therapists in the nho. not, obviously, by too many sports­ men and women with acute pain, but by patients with chronic anterior knee pain. chronic, needless to say, be­ cause it takes so long to get an appointment. biomechanics of the patellofemoral joint the normal patella with the knee fully extended, lis later­ ally and does not touch the femoral condyles. as the tibia flexes on the femur, the patella m oves medially and at 45 de­ grees the maximum surface contact with both femoral condyles is made within the trochlear notch. as the knee continues to flex, the patella again m oves laterally so that at full flexion the lateral femoral condyle is covered by the pa­ tella. the femur and patella are separated by the articular cartilage o f the patella. the patella is stabilized by the quadriceps tendon above, the patella tendon below , the lateral retinaculum, vastus lateralis and the iliotibial tract on the lateral side and by the medial retinaculum and the vastus medialis oblique on the medial side. should there be any mal­ alignment o f the patella caus­ ing altered mechanics, then the patella cartilage is at risk to injury. the physiotherapist divides her examination into two parts. the first is the subjective ex­ amination where the patient's pain is identified and its be­ haviour pattern is noted. past and present history is included. the patient's shoes and sports shoes must routinely be exam­ ined for any abnormal strike pattern. in the objective examination many factors are taken into consideration including obser­ vation o f the patient standing, walking and running. one is looking at the alignment o f the lower lim b, foot posture and structure, the tibia-femoral joint and the patella-femoral joint. the patellofemoral joint reaction force is the force cre­ ated when the patella is pressed against the femur. this force increases with flexion o f the knee from 0 .5 times the body weight in walking to 3-4 times the body weight when ascend­ ing or descending stairs and 7-8 times the body weight dur­ ---------------:---------------------17 sportgeneeskunde vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy ing squatting. pain and jo in t range is carefully noted during the testing o f these m ove­ m ents as they are most likely to be painful. as it is possible that the pain may be referred from the mid lum bar spine, this too is assessed. t ightness o f struc­ tures are checked and include rectus fem oris, iliotibial band, ham strings, gastrocnem ius and soleus. t h e norm al tibia fem oral exam ination as well as all m ovem ents o f the patella fem oral jo in t are m oved pas­ sively and com pared to the o th er leg. t he fact that the medial plica may cause sym p­ tom s m ust not be forgotten. o ther clinical evaluations are carried o ut including m eas­ urem ents o f the follow ing with the knee fully extended and relaxed: 1. t h e q angle. t his is the intersection o f a line draw n from the an terio r superior iliac spine through the m iddle o f the patella, and a line draw n from the tibial tubercle through the middle o f the patella. t he norm al angle is betw een 13 and 15 d egrees. g reater o r lesser degrees may be the cause o f p atella cartilag e deg en ­ eration. 2. t h e p ate llar g lide is the passive m ovem ent o f the p atella eith er laterally o r m edially. 3. t he p atellar t ilt is the com parison o f the height o f the m edial facet o f the p a­ tella to the lateral facet o f the p atella in relationship to the underlying fem ur. u n d e r n o rm al c irc u m ­ stances they are equidis­ tant. 4. p atellar rotation can be calculated using the infe­ rio r pole o f the patella as the guide. if the pole moves medially the patella has rotated internally and if the pole moves laterally then the patella has rotated e x ­ ternally. f inally the quadriceps m uscle itself is examined with particular em phasis on v astus m edialis o blique. v astus m edialus consists o f two parts. the proxi­ mal has large fibres directed vertically and only deviating 15 to 18 degrees from the long axis o f the fem ur. t h e distal part nam ed v astus m edialis o blique (v m o ) has sm aller fibres which are m ore h o rizo n ­ tal, deviating 50 to 55 degrees from the fem oral axis. they form the bum p readily seen and palpated when the quadriceps contracts strongly with the leg in full extension. t h e v m o m uscle is also seen on dissec­ tion , to originate partially from the adductor longus m uscle and the adductor m agnus tendon. a lthough there are n um er­ ous factors such as an incorrect q angle which may create ca r­ tilage traum a leading to patel lofem orral pain o r c h o n d ro m a­ lacia patellae, jenny m cc on­ nell postulated that the reasons m ay also be: 1. a lateral gliding o f the p a­ tella due to tightness o f the lateral structures such as the iliotibial band and the lateral retinaculum and a w eak vm o . 2. a lateral tilting o f the pataping tech n ical to co n tro l p a te lla la te ra l g lid e , m ed ia l tilt a n d internal rotation. tella due to tight deep lateral retinacular fibres. 3. an incorrect rotation o f the p atella associated with a weak vm o. h er treatm en t consists o f m obilization to stretch the late­ ral retinaculum , physiotherapy m odalities for pain, stretching o f tight structures and re­ training o f the v m o . at the sam e tim e, the patient is taught to strap his p atella in such a w ay as to co rrect abnorm al tilt­ ing, rotation and gliding. the tape is applied very firm ly and is kept in position for a few hours a day. l o n g er m ay cause breakdow n o f the skin. f inally the v m o is trained to co n tract first in a non-w eight bearing p ro g ram m e o f ex er­ cises. t he instruction to the patient is to tighten the medial q uadriceps by using the ad ­ d u c to rs is o m e tric a lly w ith extension o f the knee and slight external rotation o f the hip. t rain in g is then p rogressed to w eightbearing with the knee 18 ------------------------------------------------------------------spo rts m e dicin e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy flexed to 30 d egrees, the body w eight o v er the foot and the foot itself in mid position b ut slightly supinated. it is e x ­ trem ely difficu lt to train this m uscle w ithout co ntracting vastus lateralis. by flexing the hip, rectus fem oris is partly inhibited. f o r this reason the exercises are first done in sitting position. o nce the patien t can successfully co n tract and hold the contraction o f the v m o w ith 30 d egrees o f knee flexion, the exercises are progressed to 75 de­ grees knee flexion, then h alf squatting, three q u arte r squats and stairs w ith the m uscle w orking both concentrically and eccentrically. f in ally functional ex er­ cises are p erform ed w hile concentrating on co ntracting the v m o . p hysiotherapists are often accused o f lack o f research and although this is often true, in this case, on perusal o f the literatu re, there seem s to be adequate ev idence to support the success o f this type o f treatm ent as one way o f dealing w ith c hond ro m alacia patellae. a clin i­ cal trial o f the m cc onnell p rogram m e for 116 patients produced excellent to good results w ithin five treatm ents o f 86 p ercen t o f patients and these results w ere m aintained for one year after cessation o f the treatm ent. sceptics will arg u e that it is im possible to alter patella tracking by taping. h ow ever it is seen in the literature that the taping m ust be part o f the p ro g ram m e in o rd er to obtain good results. t h e subject o f the m cc onnell a p ­ proach to the m anagem ent o f c hron drom alacia p atella, is on the program m e o f the forthcom ing congress o f the in ter­ national f ed eratio n o f m anipulative physical t herapists to be held in a m er­ ica this year. i look forw ard to hearing the o utcom e o f the papers presented there. i f anyone w ould like m ore in fo r­ mation about the m cc onnell approach contact t h e c h airm an , s ports interest g roup, south a frican society o f p h y sio ­ therapy, 7 n y ala r oad, a m anzim toti 4125. references on request. subscription to sports m ed ic in e dear doctor, the characteristic that distinguishes a profes­ sional from an educated person is the professional person's desire and responsibility to stay abreast o f the development o f his or her field o f expertise. the halflife o f our professional knowledge is about 3 years, and for this reason it is vitally important to continuously refresh and supplement our knowledge. sports m edicine, the official mouthpiece o f the sa sports m edicine association, has over the years becom e a treasured source o f knowledge for the health care professional in the sports medicine arena. the journal features not only original research papers and articles by leading specialists in sports medicine, but also current news and relevant abstracts. your subscription to sports m edicine is an investment in your future o f the health care profession. w e count on your continued support. name: address: c o d e :......................... tel: enclosed please find my cheque/postal order payable to sasm a for: • r75 for fu l l membership to sasm a (this includes receiving sports m edicine free o f charge). • r75 for associate membership to sasm a (this includes receiving sports m edicine free o f charge). • r50 for student membership to sasma (this includes receiving sports m edicine free o f charge). • r 27,50 + v at (r 30,25) for subscription to sports m edicine. ---------------------------------------------------------------------------- 19 spo r tg e n e esku n d e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy restriction of ankle and foot movements using the standard elastic ankle guard i seels, j begley, f f u tc h er and j mitchell abstract a pilot study was conducted to compare the range o f movement o f ankle dorsiflexion and plantarflexion, and foot inversion, without and with the use o f a standard elastic ankle guard. a sample o f nine normal, healthy, physically active, caucasian males, aged 19 to 21 years, with no history o f ankle injuries, was used. the results o f this study showed no significant differences (p = 0,05) between the ankle and foot movements performed without and with the use o f the ankle guard in any o f the basic movements measured. it was concluded that the standard elastic ankle guard does not significantly restrict these movements and, therefore, is not effective for this purpose in the preven­ tion and/or rehabilitation o f ankle injuries. in t r o d u c t io n t he increased participation in various sporting activities to ­ d a y 's society is concom itant with an increase in sp o rt-re­ lated injuries. a nkle injuries, particu larly lateral ligam ent com plex sprains, are the most jeanette mitchell department o f physiotherapy university o f the wirwatersrand medical school 7 york road parktown johannesburg 2193 frequently s e e n .1'7 in the re ­ habilitation o f such injuries, patients are often advised to use the standard elastic ankle guard. this regim e o f therapy im plies that the ankle guard has a dual function: to prevent excessive m ovem ent so as to prom ote healing during the initial stages o f rehabilitation, and to p re v e n t ex cessiv e m ovem ent on return to norm al sporting activities, thereby preventing a recurrent injury. h ow ever, the question arises: does the ankle guard suffi­ ciently restrict the basic ankle and foot m ovem ents and en ­ hance ankle stability? this pilot study was designed to m easure and com pare the norm al basic ankle and foot m ovem ents o f dorsiflexion, plantarflexion and inversion in p h y sic a lly ac tiv e su b jects, w ithout and with the use o f a standard elastic ankle guard, with the aim o f establishing its effectiveness in the reh abilita­ tion/p rev en tio n o f ankle inju­ ries. m a t e r ia l s a nd m e t h o d s sam ple selection to obtain the sam ple for this study, questionnaires w ere distributed to 75 c aucasian males betw een the ages o f 19 20 -------------------------------------spo rts m edicin e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy figure 1: n eutral p o sitio n o f ankle an d f o o t and 21 years, randomly selected from th ird -y ear medical and allied medical classes at the u niversity o f the w itw aters rand, johannesburg. o f the 48 q uestionnaires returned, 22 indicated that the subjects w ere healthy and physically active, with no previous ankle inju­ ries. h ow ever, only 15 o f these subjects w ere prepared to participate in the study. on exam ination o f their ankles, it was found that a further six subjects had to be elim inated due to above average ankle circum ference (the range ac­ cepted for this study was 17 23 cm) (n = 2) and hyperm o bile ankle jo in t m ovem ents (n = 4). t he final sam ple co n ­ sisted o f nine subjects, with an average age o f 2 0 ,4 years. inform ed consent was obtained from each o f the subjects prior to com m encem ent o f the study. t esting procedure the subjects w ere each tested in three sessions: • session i each subject follow ed a w arm -up program m e co n ­ sisting o f cycling on an exercise cycle for three m inutes at a speed o f 120 revolution per m inute and a workload o f 400 kilopond m etres per m inute. t h ere­ after, the m uscles o f the p o s te rio r and a n te rio r com partm ents o f the d o m i­ nant leg w ere stretched for 30 seconds each. the foot was passively circu m d u c­ ted for the sam e period and then placed in a w arm foot bath for up to 30 seconds, after which the subject perform ed the required ankle and foot m ovem ents on the dominant side. these w ere ankle dorsiflexion, ankle plantarflexion, and inversion o f the foot, each o f which was m easured. • session 2 t he follow ing day, each su b ject p articip a ted in the sam e w arm -up p ro ­ gram m e. t he dom inant foot was dried well and pow dered with a fungicidal pow der to prevent any p o ssib le c ro s s -c o n ta m i­ nation o f undetected skin infections and to ensure ease o f application o f the ankle g uard. the guard was applied according to the m an u fa ctu rer's speci­ fications and each subject again p erform ed the re­ quired ankle and foot move­ m ents, as above. • session 3 t he sam e p rocedure as that o f session 2 w as repeated figure 2: m easurem ent o f ankle p lan tarflexion ---------------------------------------------------------------------------- 21 spo r tg e n e esku n d e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy f ig u re 3 : m easurem ent o f ankle dorsiflexion f ig u re 4 : m easurem ent o f f o o t inversion 5 0 4 0 3 0 20 10 0 d o r s i f le x i o n p la n t a r f le x io n in v e rs io n m o v e m e n t s s e s s io n 1 hm9 s e s s io n 2 czh s e s s io n 3 f igure 5: ankle a n d f o o t m ovem ents 22 — — spo r ts m e d ic in e vol. 7 no. i d e g re e s the follow ing day. m easu rem en t p rocedure all m easurem ents w ere taken with each subject reclining in the half-lying position on a plinth. t he dom inant leg was flexed at the hip and knee and the leg supported below the knee on a re-education board, on a stool. t he neutral position o f the limb as regards rotation at the hip o r knee was m ain­ tained by applying manual p ressure to the leg ju st above the ankle. p rio r to each m eas­ urem ent, the neutral position o f the ankle and foot was d e ter­ m ined using an l-shaped a lu ­ m inium piece, strapped to the foot w ith non-elastic adhesive tape, and an adjustable triangle (f ig u re 1). t h e follow ing m ovem ents w ere then m easured three times and the mean value obtained: • p lantarflexion t h e m axim um p lan tarflex ­ ion o f the an k le jo in t was m easured using the ad ju st­ able triangle as shown in f ig u re 2. • d orsiflexion in o rd er to m easure the m axim um dorsiflexion o f the ankle jo in t, a right angled foot board was placed against the sole o f the foot and the subject was asked to perform the m ove­ m ent. t he d istance b e­ tw een the footboard and the upper end o f the l shaped alum inium piece was m easured (f ig u re 3). t h e deg ree o f dorsiflexion w as then calculated using trig o n o m etric ratios, viz. sin 0 ) = opposite side/ r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy t a b le 1: a nkle and foot m ovem ents dorsiflexion plantarflexion inversion a b c a b c a b c sample mean (degrees) 17,9 17,6 18,6 41,8 40,2 41,7 35,4 36,8 34,2 s.d. (degrees) 4,0 4,9 4,1 2,0 2,5 1,9 4,3 9,0 7,9 ence (p = 0 ,0 5 ) between the an k le and foot m ovem ents p e r­ form ed with and w ithout the use o f the ankle guard. n either w as there a significant d iffer­ en ce betw een those m ove­ m ents perfo rm ed during ses­ sions 2 and 3. d is c u s s io n a nd c o n c l u sio n s hypotenuse. • inversion because the inversion in j ury o f the lateral ligam ent com plex o f the ankle o c­ curs m ost often when the foot is rotated inwards while in plan tarflex io n , this posi­ tion o f the foot and ankle w as taken to represent in­ version for the purpose o f this study. in o rd er to m easure inversion o f the foot, the su b ject's heel was placed on an a5 sheet o f p aper and a m ovable lamp positioned so that the light cast a sharp im age o f the arm o f the l-shaped alu ­ m inium piece on the paper. t h e subject first plantar flexed the ankle and a line w as draw n along the sha­ dow on the paper. t h e foot w as then inverted and a second line draw n o v er the shadow (f ig u re 4). t he angles m ade betw een the two lines w ere m easured, using a p ro trac to r. this m easurem ent w as taken as the deg ree o f inversion o f the foot in each subject. d ata m anagem ent t he data obtained by this m easurem ent pro ced u re was statistically analysed using the w ilcoxon signed-rank test, to establish if there w as a signifi­ cant d ifference (p = 0 ,0 5 ) b e ­ tween the various ankle and foot m ovem ents with and w ith ­ ou t the use o f the ankle guard (sessions 1 and 2). t h e data collected in session 3 w ere sim ilarly com pared with that from session 2 (both involving the use o f the ankle guard) to establish if there w as any sig­ nificant change in the deg ree o f ankle and foot movement which may have been attributed to changes in elasticity o f the ankle guard with tim e and use. r e su l t s t h e m eans and standard d e­ viations for the sam ple (n = 9), for each o f the ankle and foot m ovem ents (dorsiflexion, plantarflexion and inversion) are shown in t able 1. t h e data obtained for the m ovem ents perform ed w ithout the ankle guard (session i) and for movements with the ankle guard w orn (sessions 2 and 3) are shown in t able 1 and f ig u re 5. on statistical analysis o f these data, it w as found that there was no significant differc om parison o f ankle and foot m ovem ents during sessions 2 and 3 t h e fact that no significant d if­ ference w as shown between any o f the an k le and foot m ove­ m ents p erform ed during ses­ sion 2 and session 3 indicates that th ere w as no d em o n stra­ ble change in the state o f the ankle guard d u rin g the period that these m easurem ents w ere taken. c om parison o f ankle and foot m ovem ents with and w ith ou t the use o f the ankle guard the fact that th ere w as no sig­ nificant differen ce dem onstra­ ted in dorsiflex io n , p lan tar­ flexion o r inversion movements o f the an k le and foot, w ithout and w ith the use o f the ankle gu ard , suggests that the stan­ dard elastic ankle guard does not restrict these basic m ove­ m ents significantly. these findings co n cu r w ith those o f m alina, e t a l ( 1962)8, m yburgh & v aughan (1984)9, m yburgh, e t a l (1 9 8 4 )10 and r arick, et a / (1 9 6 2 ).11 t his im plies that the p re­ sum ed function o f the ankle gu ard , that is to prevent o r re­ strict excessive ankle and foot ------------------------------------------------------------------------------ 23 spo r tsg en ee sk u n d e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) physiotherapy m ovem ents, is not effectively carried out. t h erefo re, this pilot study concludes that the standard elastic ankle guard cannot be used effectively for this pu rp o se in the reh ab ilita­ tion o f the com m on ankle inju­ ries nor in contributing to the prevention o f recurring ankle sprains. h ow ever, a possible role o f the elastic ankle g uard may be to assist in the control o f post­ traum a sw elling in the initial stages o f rehabilitation. f u r­ th erm o re, the an k le g uard may supplem ent proprioception by stim ulating sensory receptors around the ankle, hence m ak­ ing the p atient m ore aw are o f the injured body part, and co n ­ sciously try to p rev en t exces­ sive m ovem ent and possible fu rth er injury. a c k n o w l e d g e m e n t s t he authors w ould like to thank the subjects who participated in the study, as well as m r b seels and m r j c raw ford for s u g g e s tin g th e m ean s to m easure and record the ankle and foot m ovem ents studied. this study w as approved by the c om m ittee for r esearch on h um an subjects, u niversity o f the w itw atersrand, johan­ nesburg. references 1. balduini fc, vegso jj, torg js & torg e. management and reha­ bilitation o f ligamentous injuries to the ankle. sports m ed, 1987; 4(5): 364-380. 2. brand rl, black hm & cox js. the natural history o f inadequately treated ankle sprains. amer j sports m ed, 1977; 6: 248. 3. garn sn & newton ra. kinaes thetic awareness in subjects with multiple ankle sprains. pliysther, 1988; 68(11): 1667-1671. 4. glick jm, gordon rm & nishim ito d. the prevention and treat­ ment o f ankle injuries. amer j sports m ed, 1976; 4: 136-141. 5. gross mt. effects o f recurrent lateral ankle sprains on active and passive judgements o f joint posi­ tion. phys ther, 1987; 67(10): 1505-1509. 6. kay db. the sprained ankle: cur­ rent therapy. foot ankle, 1985; 6(1): 22-28. 7. lassiter te, malone tr & garrett we. injury to the lateral ligaments o f the ankle. ortliop clinics n amer, 1989; 20(4): 639. 8. m alinarm , phagenzlb & rarick gl. the effect o f exercise upon measurable supporting strength o f cloth and tape ankle wraps. res quart, 1962; 34(2): 158-165. o th er references on request thrombophob gel “ high heparin content' in a clear n0n-greasy gel brings immediate tissue penetration alleviates pain, bruising and promotes tissue healing. per loog: hepann 20 000 i.u. hexachtorophene o.ig © moristan laboratories division of moristan limited 326 marks street, a/altloo, pretoria. jnder licence of nordmark arzneimittel 3mbh, germany. gel: |§t| g 1635 (act 101/1965) full details on composition, indications, contra-indicatic side effects and precautions are available on request. r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasma news think globally, act locally p r o f t im n oakes president sasma at present the challenges and o pportunities for the dev elo p ­ m ent o f sports m edicine in this country have never been g rea ­ ter o r m ore exciting. a s o fm a rc h 1992, the south a fric a n s p o rts m e d ic in e a ssociation will be invited to becom e a full m em ber o f the international federation o f s ports m edicine (f im s ). it is a trib u te to o u r form er p resi­ dents, drs clive noble, etienne h ugo and d aw id van v elden that finally we have achieved this b reakthrough. o f related interest is the invitation to d r m artin schw ellnus to serve as the a frican representative on the educational c om m ittee o f f im s . this provides an im ­ portant opportunity for our association to be o f assistance to the developm ent o f sports m edicine throughout a frica. t he o ther source o f ex cite­ ment is the possibility o f o lym pic and o th er in tern atio ­ nal com petition in the near future and the dem ands and o pportunities that will arise as a result. t h e c u r r e n t po sit io n o f spo r ts m e d ic in e in so u t h a fr ic a c o m pa r e d to o t h e r sim il a r c o u n t r ie s in all countries, s ports m ed i­ cine has a com m on origin: a g roup o f enthusiastic d octors/ athletes get together to discuss how their hobby (sport) relates to their profession (m edicine). f o r most o f these enthusiasts, th eir interest in sports m edi­ cine is peripheral to how they earn their livings in m edicine. t w o d ifferent m odels o f s ports m edicine a ssociations have evolved at least in the w est, with a third possible model arising in eastern e u­ rope. in the first, the a ssociation is m ore o f a "club" with an exclusive m em bership. the principal function o f the "club" seem s to be to insure that the interests o f its m em bers are served; the service that the "club" o ffers to the athletes is entirely peripheral to its role in satisfying the needs o f its m em bers. such organizations are not likely to gain either academ ic credibility o r the sup­ port o f their co u n tries' athletes. this model is a recipe for d is­ aster and m ust be avoided at all costs. t h e second model is the type exem plified by w hat has happened in the u nited states and c anada. in these coun­ tries, s ports m edicine has evolved with a very strong sci­ entific and clinical background led by persons who are re­ spected as leaders in their medical fields eith er as o rth o ­ paedic s urgeons, c ard io lo ­ gists, psychologists, exercise scientists, etc. t h e result is that s ports m edicine in those countries has achieved cred i­ bility am ongst the scientific and academ ic com m unities and is m oving rapidly to being ac­ cepted as a m edical speciality. in addition because the a sso­ ciations have evolved p rin ci­ pally to aid athletes not doc­ tors, they have also gained the credibility and support o f the athletes. t h e third model is that p ro ­ vided by the fo rm er eastern european countries, in p articu ­ lar the fo rm er east g erm any (g erm an d em ocratic r epublic -g d r ). in that co u n try , sports m edicine thrived not so much because o f a strong scientific b ackground, but because it was the political m ission o f that country to succeed in sport. as a result w hatev er resources necessary to achieve that goal w ere dedicated to that p u r­ pose. t h e end result was that, o f all cou n tries, it w as probably the athletes from the g d r and other east e uropean countries w ho received the most scien­ tific and m edical support. t he basis for a successful s ports m edicine pro g ram m e is the right com bination o f the follow ing factors: dedicated p ractitioners w ho are co m m it­ ted to the help o f athletes; a strong scientific basis for the w ork so that academ ic cred ib il­ ity can be achieved; a basis for ----------------------------------------------------------------------------25 spo rtg e n e esku n d e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasma news still needs to be done. negative factors • there is no official national political mission to make international success in sport an important priority in this country. until this happens, state funding for sports medicine and the exercise sciences, on a decent scale, w ill not be priority. • there is no teaching o f sports medicine in the undergraduate m ed ical curriculum which is, un­ fortunately, an indirect measure o f the importance that our colleagues in aca­ demic medicine ascribe to our interest. promote our speciality to the benefit o f all in this country. sports m edicine is a global enterprise and i f south africa is to make its mark at an inter­ national level, w e must pool our resources. immediate plans to address these issues as the famous chinese prov­ erbs states, "a journey o f a thousand miles must begin with a single step". here are the single steps that w e will be emphasizing in the next 2 years: further development of our journal professional sport so that doc­ tors can be em ployed full-time in the profession; and political w ill that sport is important to the national interest. with this background, it is appropriate to consider how south africa currently ranks and what needs further im ­ provement. the current position in south africa positive factors • south africans do live in a "sports-mad" society in which sport enjoys a high profile including and most importantly, at schools. • the standard o f training o f doctors and the profes­ sionals allied to medicine, is very high so that any potential recruits into the sports m edicine discipline are likely to have been highly trained, disciplined and very competent in their work. • south africa is about to enjoy the benefits o f a re­ turn to international com ­ petition and this is likely to be follow ed with increased public support of, and in­ terest in sport and there­ fore also in sports m edi­ cine. • south africa has a viable sports m edicine a ssocia­ tion with its own journal. furtherm ore, scien tific research in sport does at least have a firm base in this country, although much • w e do not yet have a sports medicine programme that leads to specialist qualifi­ cation ir. this discipline. in the long term this must be addressed. in the short term we need to develop the concept o f group multi­ disciplinary practices in sports medicine. • there is no really profes­ sional sport in this country. nor are many o f our sports administrators sufficiently professional to be planning ahead in particular by in­ v e s tin g in s c ie n t if ic studies in their sports. • w e have the problem o f re­ gional and ethnic parochi­ alism. w e must work very hard to eradicate these negative influences which w ill get in the way o f our real mission which is to the journal w ill take on more o f a continuing medical edu­ cation flavour. it will becom e more substantial and pub­ lished on a more regular basis. whilst most o f the effort for this development w ill com e from the full-time academics, it is hoped that members w ill be en co u ra g ed to con trib u te material for publication. increasing the activities of the regional committees at present the association has active regional com m ittees in the s o u th ern t ra n sv a a l (chairman: dr joe skowno),. northern transvaal (chairman: dr u li schmidt), the orange free state (chairman: dr ras venter) and the western cape (chairman: dr wayne der man). w e hope to extend these branches to natal and the eastern province in the near 26 ---------------------------------sports medicine vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sasm a news future. regional branches can only be successful if they are sup­ ported by members from all the major groupings making up our association including physio­ therapists, biokineticians, ex­ ercise scientists and doctors. upcoming congresses in collaboration with the south african rugby football union the association w ill be holding a two day congress on april 9th and 10th, 1992. topics that w ill receive special attention w ill be traumatology and sports nutrition. the a ssociation's next in­ ternational sports m edicine meeting w ill be on the week o f the 9 13th march 1993 in cape town. during the year, a series o f regional meetings on olympic sports m edicine w ill be co ­ ordinated. extending ties with colleagues in the professions allied to medicine physiotherapist and members o f the other professions allied to medicine make an important contribution to our a ssoci­ ation. the rights o f these collea­ gues w ill be discussed at the next annual general meeting in march 1993. development of a regional olympic sports medicine programme should south africa be repre­ sented to any great extent at the barcelona olympic games, there w ill be a n ek l for the provision o f sports medical care on a regional basis to the athletes preparing for those games. the association is presently in consultation with the federation o f m ovement sciences (formerly saasper) who have been given the mandate to develop this pro­ gramme. report back from the regions southern transvaal dr joe skowno the southern transvaal re­ gional branch o f the south a frican sports m ed icin e association held three meet­ ings in the latter half o f 1991. the last one on novem ber 6th was particularly w ell attended, with over 60 people present. the subject under discussion was management and rehabili­ tation o f shoulder injuries. drs pierre roussouw and bryan n oll discussed the anatomy, pathology and management o f rotator cu ff and instabilities. a practical demonstration o f ex ­ amining a patient with supras pinatus im pingem ent syn­ drome was given. mrs joanne sklaar covered rehabilitation most comprehensively. an encouraging feature o f the evening was the tremendous amount o f audience participa­ tion. m eetings held in 1992 to date include: alternative medicine in sports injuries 22 january 1992 the m odem approach to ankle injuries 11 march 1992 an important objective o f the southern transvaal regional sports m edicine group w ill be to establish a roster o f emer­ gency sports care personnel in the southern transvaal. the aim is to train doctors and physiotherapists to deal with any emergency one might rea­ sonably encounter during any sports activity. the idea is to supplement existing first aid services currently available at most large sporting occasions, and not to replace them. the aim w ill be to work with st johns and noodhulpliga who supply general medical care and ambulance services. dr skowno has expressed the opinion that the sports m edi­ cine association should be ac­ tively involved in the estab­ lishment o f an independent body to co-ordinate doping control in south african sports. any doctors who are actively involved in this area are en­ cou raged to con tact dr skowno. dr skowno's address is po box 6 7196, bryanston 2021. parke-davis medical 10 road race boosts victoria hospital fund the popular medical 10 road race, sponsored and hosted by parke-davis, a division o f w arner-lambert sa (pty) ltd, for the forth consecutive year, took place o f 7 december ------------------------------------- 27 sportgeneeskunde vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) s a s m a n e w s seen at the finish o f the popular parke-davis medical 10 road, race are, (l-r): dr adrian morrison from victoria hospital, d r helmut elmau and dr kelly seymour, medical director of'warner-lambert 5/1 (pty) ltd. 1991. t h e 10 km m edical 10 road r ace for m edical doctors and 3 km fun run for cardiac rehabilitation patients, known as h eart t h ro b s, started and finished at p ark e-d av is' head office in r etreat. f o r the first tim e this year, there was an entry fee o f rio. a greed to last y ear by 300 entrants w ho com pleted a q u es­ tionnaire, it was decided that the p roceeds o f this y e a r's race w ould be earm arked for the v ictoria h ospital c asualty unit f u n d . e arlier this year, p arke-d avis announced their decision to com e to the aid o f the hospital and this event is part o f th eir on-going effo rt to raise the r 1,3 m required to re ­ build the casualty unit. a pproxim ately 228 m edical doctors and 70 h eart t hrobs com pleted the m edical 10 road r ace and 3 km fun run re ­ spectively. this y ear runners w ere again handicapped 30 seconds p e r y ear o f age from 40 upw ards. a m etro helicopter, pri m ed a m bulance as well as medical staff from v ictoria h ospital w ere on stand-by for the first tim e this year, co n trib ­ uting to the high standards that have co m e to be expected o f the p arke-d avis m edical 10 road race. at the p rize giving breakfast follow ing the race, c o uncillor b ronnie h arding accepted a cheque on b eh alf o f v ictoria h ospital. ian r obertson, m ar­ keting d irecto r o f p arke-d avis and t im l argier, m anaging d irecto r o f w arn er l am b erts a (pty) ltd, aw arded prizes to w inners in various categories. t h e sp ecia lly d esig n ed m edical 10 floating trophy for the fastest ru n n er overall on handicap was presented to d r f r a n c o is h o f m e y r fro m w ynberg who com pleted the 10 km run in a tim e o f 31 m inutes and 7 seconds. f o r the first tim e in the history o f the race, gold m edals w ere aw ar­ ded to the first male as well as fem ale on handicap and medals w ere presented to d r h ofm eyr and d r c lare stannard from r ondebosch. silver and b ro n ze medals for second and third positions on handicap for males w ere presented to d r e ric bateman from r ondebosch and d r r ob­ bie t ru te r m edical superinten­ dent o f t y g erb erg h ospital respectively, w hile medals for the second and third fem ale runners w ere aw arded to d r lana van zyl and d r e g od­ dard respectively. g old m edals for the fastest m ale and fem ale runners w ere presented to d r a ndrew leary w ho com pleted the race in an outstanding actual tim e o f 33 m inutes and 6 seconds and d r l ana van zyl, the first fem ale ru n n er to cross the finishing line in an actual tim e o f 43 m inutes and 29 seconds. t he h eart f oundation o f southern a frica nom inated edw in king to receive the ian t ay lo r m em orial a w ard which is presented annually to the most deserving cardiac reha­ bilitation patient. d uring the aw ards p resen ­ tation, ian r obertson, m arket­ ing d irecto r o f p arke-d avis, com m ented, " w e 'v e received a record num ber o f en tries for this y e a r's race and w e would like to thank all d o cto rs who took part for their much needed financial support. w e also thank those w ho made fu rth er donations to v ictoria h ospital today. w e look fo r­ w ard to an equally successful 1992 m edical 10 road r ace." 28 — — spo r ts m e dicin e vol. 7 no. 1 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) editorial this edition of the south african journal of sports medicine has as its theme injuries to the hip and pelvic region in sport. although injuries to the hip and pelvis in sport are uncommon compared to other joints of the lower limb such as the knee and the foot and ankle, they nevertheless represent a specific challenge to the medical staff having to diagnose and treat these injuries. often, these injuries are particularly frustrating to the sportsperson as they consult health professional after health professional in search of a diagnosis and treatment. two review articles have therefore been devoted to discuss a clinical approach to overuse injuries of the hip and pelvis in sport. in the first of these articles, an attempt has been made to provide the reader with an overview of the injuries as they occur in the hip and pelvis and in the second article specific bony overuse injuries of the hip are discussed. overuse injuries of the hip and pelvis can be classified according to the anatomical area that is injured. a large part of the overview article focuses on injuries of the sacro-iliac joint and the symphesis pubis. these two joints have been selected because it is difficult to make a final diagnosis of injuries that occur in these joints. special groups of patients who develop overuse injuries of the growth plate, namely adolescent athletes, also feature prominently in the review. in the second review, dr derman discusses bony overuse injuries of the hip and pelvis, according to the type of bone that is injured. this article is par­ ticularly useful in identifying bony overuse injuries that may require surgical intervention. also, the value of using the correct imaging techniques to diag­ nose these injuries is highlighted. in summary, these two articles have attempted to provide the reader with an approach to the diagnosis and management of conditions that are frustrating to diagnose, often difficult to treat. it is hoped that this will contribute to the improved care of the athlete with an injury to the hip or pelvic region. dr m p schwellnus, mbbch, msc(med), md, facsm co-editor: south african journal of medicine sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) seventh south african sports medicine association congress 24-26 m a r c h 1997 su n c it y p e a k performance enhancement and knowledge south african sports medicine association dear delegates the theme for our 1997 congress is “ peak” performance enhancement and knowledge. this is appropriate during this time of growth and development of sasma. we are for once taken seriously by all and sundry especially our national sporting codes. it is imperative that this congress is of the highest standard and extrem ely well attended by all involved in sports medicine. running alongside the three day sports medicine program m e will be an orthopaedic traum atology programme. in addition there will be a one day general practitioner sym posium emphasizing gen­ eral practice and exercise related areas. the largest ever exhibition is planned as well as extensive social sporting events. please book early. dr shorty moolla president an outstanding congress that covers all areas of sports medicine you’ll be able to attend any o f m ore than 150 presenta­ tions covering a wide range o f disciplines everything from cardiology to exercise physiology physiotherapy to first aid, orthopaedics to neurology and much more. faxback enquiry form to: val mckenzie fax: (011) 402-0164 post: p.o. box 53101, troyeville, 2139 tel: (011) 402-3240/53/57 (to reach us before 30 november 1996) 1. i am interested in p re se n tin g a free paper. please send m e an abstract fo rm . 2. i w o u ld lik e to s u g g e s t.................................... ..........................................as a p o te n tia l speaker, c o n ta c t tel: ........................f a x : ............................ 3. i w o u ld lik e m ore in fo rm a tio n a b o u t e x h ib itin g at the congress. 4. please ensure that i re ce ive m ore in fo rm a ­ tio n on this e x c itin g sa sm a congress. 5. please ensure that i rece ive m ore in fo rm a ­ tio n on the o rth o p a e d ic congress. 6. please ensure th at i rece ive m ore in fo rm a ­ tio n on the 1 d a y gp sym p o siu m . miss n a m e :............... s u rn a m e :.......... m r ......... m rs .. p o s itio n ................................ c o m p a n y /u n iv e rs ity etc. postal address..................... dr.. prof tel . fax phone: +27 11 402-3240/53/57 mail to : x po box 53101 troyeville, 2139 fax to: +27 11 402-0164 2 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) tiie sottii african journal of sports medicine volume 3 number 3 september 1996 editors p roft d noakes contents dr mp schwellnus editorial board editorial 1 dr m e moolla d r p de jager dr j s k ow n o contents 3 dr p schwartz p rof r stretch dr c de ridder p rof b c andrews dr e w derman mr r h farman overuse injuries of the hip and pelvis in sport e w derman mp schwellnus 4 p rof r ii mars dr c a noble international advisory board stress fractures and bone stress injuries of the hip and pelvis mp schwellnus 14 lyle j micheli associate clinical professor o f o rthopaedic surgery boston, usa chester r k yle research director, sports equipment research a ssociates california, usa prof h c wildnr ilollmann president des deutsehcn sportarztcbundcs kohi, west germany rights, obligations and utility in sports medicine research s olivier sports related head injuries: a neuropsychological perspective sj anderson 19 23 howard j green professor, department o f kinesiology ontario, canada product news 28 george a brooks professor, department o f california, usa neil f gordon director, exercisc physiology texas, usa edmund r burke associate professor, biology department, university o f colorado colorado, usa graham n smilh p h ysiologist glasgow, s cotla n d the editor the south african journal o f sports medicine po box 115, newlands 7725 production andrew thomas publishing glenbarr publishers cc private bag x 14 paiidands 2 1 9 6 tel: (o i l) 4 4 2 -9 7 5 9 fax: (o i l) 8 8 0 -7 8 9 8 ad vertisin g andrew thomas reproduction output reproduction printing hortors reparil-gel relieves muscular pain the views expressed in individual articles arc the per sonal views o f the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent o f the publishers. sports medicine september 1996 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) overuse injuries of the hip and pelvis in sport clinical diagnosis and management of common overuse injuries: a review dr m p selnvellnus (mbbch, msc (med), md, facsm) dr e w derman (mbchb, bsc (medxhons), phd, facsm) introduction this article is devoted to overuse injuries o f the hip and pelvis in sport. overuse injuries in this anatomical area can b e very difficult to diagnose and therefore manage. in particular, conditions in the sacroiliac joint and the symphysis pubis can b e frustrating as athletes often end up with chronic pain that prevents them from com pet­ ing. m edical professionals treating these conditions are equally frustrated in trying to pinpoint the exact nature o f the aetiology and pathology o f these conditions. in our practice, we refer to patients with chronic groin or but­ tock pain that have consulted a variety o f m edical prac­ titioners as presenting with the “ difficult groin syn­ drom e” and the “ difficult buttock syndrom e” respec­ tively. a s a result, we have, over years, developed an approach to deal with the “ difficult groin syndrom e” and the “ difficult buttock syndrom e” . t h e aim o f this review article is to focus on the clini­ cal assessment o f th e athlete presenting with pain in the hip and pelvis, and to discuss som e o f the m ore com m on overuse injuries that can occur in this region. t he major portion o f th e discussion is devoted to conditions that are unique to sports participation rather than conditions that also occur in the non-athletic population. bony overuse injuries o f the hip and pelvis are covered in a separate article in this issue. overuse injuries of the hip and pelvis in sport overuse injuries o f the hip and pelvis in sports are m ore com m on than acute traumatic injuries.' in com parison to the knee, lower leg and foot, overuse injuries o f the hip and pelvis are relatively uncommon in athletes. in several large surveys, injuries to th e hip and pelvis accounted for only between 2.6 and 5% o f all reported injuries.2 because these injuries are not frequent, they have not b een well studied. however, these injuries are often difficult to diagnose and can b e frustrating to treat. t he frequency and type o f overuse injuries o f th e hip address for correspondence: dr m p scliwellnus senior lecturer department o f physiology university of cape town medical school sports science institute of south africa boundary road newlands 77 2 5 south africa and pelvis have been reported in one large survey.' in this study on 204 athletes (114 males, 90 fem ales) pre­ senting with hip and pelvis injuries, bony injuries accounted for 35.5% and soft-tissue injuries for 64.5% o f all injuries. t he frequency o f occurrence o f specific bony and soft-tissue injuries was noted to b e different in males and fem ales and is indicated in table 1 (bony injuries) and table 2 (soft-tissue injuries). table 1: b ony overuse injuries o f the hip and pelvis in athletes (prevalence as % o f total h ip and pelvis injuries) injury m ales fem ales sacroiliitis 6.4 15.6 pelvic stress fracture 9.0 7.0 osteitis pubis 7.1 7.9 osteoarthritis o f hip 4.2 3.1 apophysitis (iliac crest) 3.2 3.0 apophysitis (ant sup iliac spine) 2.0 1.0 sacral injury 0.8 1.0 from lloyd-smilh e t al 1985 table 2: s oft tissue overuse injuries o f the liip and pelvis in athletes (prevalence as % o f total hip and pelvis injuries) injurym ales g luteus m edius tendonitis 13.5 trochanteric bursitis 15.1 hamstring strain 9.5 iliopsoas strain 7.9 a ddu ctor strain 9.5 piriform is strain/ syndrom e 4.0 from lloyd-sm itli el. al 1985 overall the m ost com m on bony injury was sacroiliitis (10.3%), followed by pelvic and femoral neck stress frac­ tures (8.1%), osteitis pubis (6.3%), osteoarthritis o f the hip (5.4% ), apoph ysitis o f th e iliac crest (3.1% ), apophysitis o f the anterior superior iliac spine (1.4%) and sacral bone stress in ju r y (0.9%). the m ost com mon soft tissue overuse injury was strain o f the gluteus m edius m uscle (18%). this was followed by trochanteric bursitis (16.7%), hamstring strain (9.5%), iliopsoas fem ales 24.0 18.8 9 .4 '5.2 2.1 2.1 4 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) strain (6.8%), adductor strain (6.3%), and piriformis strain/syndrom e (3.1%). overuse injuries o f the hip and pelvis can also be clas­ sified according to the anatomical structures involved. a convenient classification is to divide overuse injuries o f the hip and pelvis into those that affect join ts (sacroili­ ac, pubic symphysis, hip, lumbar spine), bones (lumbar vertebrae, sacrum, pelvic ring, femur), soft tissues (muscles, tendons, ligaments, bursae, nerves, blood ves­ sels), and growth plates (table 3). pathology in pelvic organs such as bowel, bladder, reproductive organs can give rise to referred pain, and must also b e considered (table 3). t he aetiology, clinical diagnosis and manage­ ment o f m ore com m on overuse injuries o f the hip and pelvis will now b e discussed. overuse injuries of the joints sacroiliac join t dysfunction introduction the sacroiliac joint is the m ost com m on site o f bony overuse injury in the hip and pelvis region o f the ath­ lete.1 it appears to b e more com m on in fem ales than males. it is not clear whether this is related to gender differences in the functional or structural anatomy o f the pelvis. aetiology and m echanism o f injury t he precise aetiology and m echanism o f injury in this condition has not been well established. however, the postulated m echanism o f injury is an increase in the shear force across the sacroiliac joint during running. t he shear forces can b e increased under the following conditions: weakness o f the abductor muscles muscle strength imbalances between the two hip joints3 running on uneven surfaces leg length discrepancies (found in 44% o f patients with this condition)1 associated non-athletic conditions such as ankylosing spondylitis varum alignment o f the lower limb (it is not clear from the study by lloyd-smith precisely what type o f varum alignment is a particular risk factor) the precise m echanism o f how shear forces produce movem ent and how this causes pain is not well under­ stood. it has been shown that patients with sacroiliac joint dysfunction have antagonistic movement o f the two innominate bones ie. when the one innominate bone tilts anteriorly th e other one will tilt posteriorly.3 t he m ove­ m ent o f the sacrum is not documented. pathology the pathology o f sacroiliac join t dysfunction is pre­ sumed to b e inflammation in the joint. this has howev­ er not been well documented. clinical diagnosis t he main symptom o f sacroiliac join t dysfunction is pain in the lower back or buttock area. the pain is usually vague and is often described as stiffness. it is often more severe in the early morning or after a period o f inactivi­ ty. other characteristics o f the pain are: gradual onset o f pain precipitated by exercise but aggravated by a period o f rest after exercise episodes o f exacerbation and remission radiation to the back o f the thigh, hip joint or groin associated with pain in other sites (gluteus medius, trochanteric bursa)1 may b e associated with arthralgia in other areas o f the body on examination there is tenderness over the sacroiliac joints. t his may b e difficult in the very muscular or over­ weight patient. four tests have been described to assess th e sacroiliac joint.'’ sacroiliac joint dysfunction can b e diagn osed i f the m ajority o f th ese tests are positive. table 3: overuse in juries of the hip and pelvis: classification by anatomical area 1. overuse injuries o f the joints a. sacroiliac joint sacroiliac joint dysfunction b. pubic symphysis traumatic osteitis pubis c. hip joint degenerative osteoarthritis o f the hip d. lumbosacral joint degenerative joint disease 2. overuse injuries o f the bony structures a. lumbar vertebrae pars interarticulares bone stress degenerative spondylosis b. sacrum sacral bone stress c. pelvic ring (ilium, ischium, pubic bones) bone stress injuries d. femur bone stress injuries 3. overuse injuries o f tile soft tissue a. snapping hip syndrome snapping hip syndrome (anterior) snapping hip syndrome (lateral) b. muscles chronic muscle injuries c. nerves entrapment neuropathies d. bursa chronic bursitis e. tendons chronic tendinopathy f. other soft tissue injuries conjoint tendon injuries g. blood vessels peripheral vascular disease 4.overuse injuries o f the growth plates 5. other pelvic organ pathology bowel bladder reproductive organs sports medicine september 1996 5 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a. standing flexion test: this test detects the presence o f sacroiliac joint dys­ function. t h e patient stands in front o f th e examiner fac­ ing away from the examiner. t he examiner places the thum bs o f both hands ju st under the posterior superior iliac spines (psis) (over the sacroiliac joints). t he patient is instructed to bend forward slowly while the examiner detects cranial m ovem ent o f the posterior superior iliac spines. a test is positive i f one ol the psis m oves cranially more than the other. t h e supine long sitting test and the prone-flexion test determ ine the direction o f the innominate bone movement. b. supine-long sitting test: in this test the examiner first notes the relative posi­ tions (leg length difference) o f the m edical m alleoli while the patient is lying supine. t h e patient is then asked to sit up and shifts in the relative positions o f the m alleoli (moving apart or together) with respect to each other are regarded as a positive test. t h e direction o f tilt o f th e innominate bone can b e determ ined through this test. a posterior tilt o f the innominate will produce rel­ ative shortening o f the lim b on that side. c. prone-knee flexion: this test produces similar results to the supine-long sit­ ting test. t h e examiner first approximates the heels o f the patient lying prone on a couch. t h e patient is then asked to flex bothlcnees to 90°. any shift o f th e heels with respect to each other is a positive test. t h e results are interpreted similarly to those obtained from the supine long-sitting test. d. posterior-superior iliac spine (psis) palpation: h ie patient is asked to sit on a hard surface. t h e exam­ iner palpates the psis on both sides. any difference in th e heights o f th e two psis constitutes a positive test because it indicates tilting o f the innominate bones. special investigations special investigations are not very useful in th e diagno­ sis o f sacroiliac joint dysfunction. it may b e necessary7 to perform the following investigations to exclude other pathology: x rays bone scan blood tests (ebc, esr, hla typing) management t he management o f sacroiliac joint dysfunction is con ­ servative and is aimed at: reducing pain treating the sacroiliac joint instability preventing recurrence a. pain reduction: this can b e achieved by analgesics, alteration o f activity and physiotherapeutic modalities. b. management of the instability: three different techniques are used: isom etric contractions mobilisation manipulation the basis o f isom etric contractions is to use specific exercises to correct abnormalities in pelvic tilting. posterior tilting o f the innominate bone on one side is managed by th e following exercise. the patient is requested to lie supine on a couch with the leg o f the injured side hanging over the edge o f the couch. the therapist then applies pressure with the one hand on the thigh o f the injured leg and the other hand on the anterior superior iliac spine (asis) o f the uninjured side. a t the same tim e the athlete perform s an isom et­ ric contraction o f the hip flexor o f th e injured side. • anterior tilting o f the innominate is managed by the isom etric contraction o f the hip extensors on the injured side. m obilisation and manipulation techniques can also b e used by the physiotherapist to correct abnormal tilt­ ing o f the appropriate innominate bone. c. prevention o f recurrence: t he basis o f preventing this condition is i) to eliminate any imbalances of the hip musculature and ii) to treat any structural and functional leg length discrepancies. m uscle imbalances that are associated with this condi­ tion are imbalances o f the hip flexors/extensors and hip internal/external rotators. relative m uscle strengths o f these m uscle groups must b e assessed and imbalances corrected. traumatic osteitis ptjbis (pijbic symphysitis) introduction traumatic osteitis pubis is a general term that has been used for several disorders o f the pubic svmph vsis. pubic stress symphysis is an alternative term that is also used to refer to the painful, non-septic, inflammatory con d i­ tion that occurs in r u n n e r s and other endurance ath­ letes.4 for th e purposes o f this discussion, this condition will b e referred to as traumatic osteitis pubis. t he clinical entity o f “ osteitis pubis” was described for the first time in 1923 in patients after urological proce­ dures.5 a further description o f the condition was docu­ mented one year later.'1 in a number o f subsequent publi­ cations, a variety o f aetiological factors for this condition were described. these included case reports describing urinary tract infections,7 8 osteomyelitis o f the pubic sym­ physis,” abdomino-pelvic operative procedures,7101112131410,10 pregnancy,7 childbirth17 and certain arthriditis1819 as conditions that can cause this clinical syndrome. in m ore recent literature this condition is described as resulting from a variety o f sport activities.20 before the mid seventies reports o f the lesion following athletic activity were rare. in one publication, a patient was reported as having developed osteitis pubis from a bas­ ketba ll injury.21 however, th e con d ition was also described in an olympic road walker, '" and an interna­ tional level cricket fast bowler.23 a t present, although unusual, it is recognised as a potential consequence o f a large variety o f sport activities including soccer, i,i7.a+.as,3(i.27.s<> basketball,21 rugby,20 wrestling,2027 ice h ock ­ ey,24 ju d o,25 road walking," '" long distance running,11730 crick et,23 a m erican football,31 and h orse racing.17''1 it appears to b e m ost com m only associated with 6 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) running and kicking sports.32 a etiology o f traumatic osteitis pubis although traumatic osteitis pubis in athletes has a con­ sistent clinical presentation, the aetiology and pathogen­ esis remains controversial. a variety o f biomechanical abnormalities are mentioned as potential aetiological factors for the development o f traumatic osteitis pubis. varus alignment o f the lower extremities patients with m ild to severe varum alignment o f the lower extremities com pensate by excessively pronating the ankle and subtalar joints during the support phase o f gait.1 in one study where 204 referred patients with hip and pelvic injuries were evaluated at a sports m ed i­ cine clinic, at 62.6% o f cases had significant varus align­ ment o f the lower extremities, with rearfoot varus being the m ost frequent. t he authors proposed that varus alignment o f the lower extremities predispose a patient to hip and pelvic injuries.1 leg length discrepancy in one study, leg length discrepancy was found in 30,6% o f patients with traumatic osteitis pubis, and the authors indicated that this may cause abnormal shear forces along the pelvic joints.1 however, in this study no control group was used to assess the frequency o f leg length discrepancy in normal non-injured athletes. loss o f hip mobility reduced hip mobility has been reported in one study o f 12 cases o f traumatic osteitis pubis in one series.33 the loss in hip range o f motion included reduced internal and external rotation. however, once again no control group was assessed to compare hip mobility in injured and non­ injured athletes. t he authors proposed that the decrease in mobility, could result in excessive shear stress along the pelvic joints, including the pubis symphysis. mechanism o f injury in traumatic osteitis pubis traumatic osteitis pubis appears to as a result o f exces­ sive mechanical strain on the pubic symphysis induced by shear forces.'0 t hese shear forces can b e secondary to increased m uscle strain, m uscle weakness, decreased hip mobility, or other factors. increased m uscle action involving the adductor m us­ cles, abdominal m uscles, abductor m uscles and the gra­ cilis m uscle may result in excessive shear force on the symphysis pubis. shear force may b e induced by the adductor m uscles in running and kicking sports. in one report on three cases o f osteitis pubis the authors proposed that a shearing force results in a subacute periostitis w hich will present with clinical picture o f osteitis pubis.26 extremely forceful movem ents during sideways kicking, involving mainly the adductor m us­ cles, has been regarded as the initiating event o f trau­ matic osteitis pubis in soccer players.'4 simultaneous conditioning o f the rectus abdominus and the adductor muscles niay cause increased strain on a susceptible pubic symphysis. this has b een reported 111 a study of osteitis pubis in long distance runners w ho were involved in abdominal conditioning exercises in addition to their running program mes.30 t he unguarded force inflicted on the gracilis m uscle w hile kicking a soccerball (the leg externally rotated, adducting and violently flexing the hip) has also been postulated as a possible m echanism o f injury. in this setting, the injury m a y b e an avulsion fracture or a stress fracture at the anatomical origin o f the gracilus muscle, resulting in an internal derangement o f the symphysis pubis. this may b e a mechanism o f injury o f traumatic osteitis pubis.25 weakness o f the abductor muscle system has also been proposed as a p ossible cause for the developm ent of traumatic osteitis p ubis.1 weak abductor m uscles will cause excessive frontal pelvic m otion in runners in the coronal plane (functional trendelenberg sign). this will result in increased shearing force along the sacro-iliac joints and the pubic symphysis. running on uneven ter­ rain, varum alignment o f the lower extremities or leg length discrepancies in the athlete will contribute to this excessive shearing force.1 r estricted hip internal rotation can also cause an increased shear force on th e pelvis. during extension, a d ecreased hip internal rotation will cause m ovem ent in the saggital plane on one h a lf o f the pelvis in relation to the other. in flexion, there may b e increased movem ent in the transverse plane.133 in one study o f twelve cases o f traumatic osteitis pubis, loss o f hip m obility was dem on­ strated in all patients. t h e authors suggested that restricted hip movem ent results in excessive shearing forces w hich are the causative factor in traumatic osteitis pubis.33 repeated minor trauma to the pubic symphysis (either directly or secondary to instability o f the sacro­ iliac joints) can also result in traumatic osteitis pubis. this has been postulated as a cause o f the condition in professional footballers.17 shear forces transmitted to the pubic symphysis may also b e caused by horizontal side-to-side pelvic sway, resulting from excessive swing­ ing o f arms across the b od y w hile running.1 pathology o f traumatic osteitis pubis histopathological features seen in chronic, non-traumatic osteitis pubis include non-specific mononuclear cell infil­ trate, marked bone reabsorption and fibrous connective tissue replacement at the symphyseal flbrocartilage.19-3435 other significant histopathological findings that have been reported include the presence o f both viable and nonviable bone fragments, extensive fibrous tissue, and the absence o f any evidence o f an infectious process.25 clinical presentation symptoms t h e single m ost im portant symptom o f traumatic osteitis pubis is pain,1'4-17-20-24-26-28-30'30 t h e pain is usually insidious in onset and gradually progressive in intensi­ ty.2*’ t he nature o f the pain may b e dull124 or sharp.424 t h e m ajor site o f th e pain is in one or both groins.117 24 20 20 301x1 in som e cases the pain is primarily fel t in the suprapubic region.1 1728 t he pain may radiate from the primary site, m ost com monly along the m edial aspect o f the thigh in the region o f the adductor m uscle group,1720 but also laterally to the hip,24 towards the sacrum,24 the bladd er or the lower abdom en.17 24'38 t he pain is aggravated by movement, in particular abduction sports medicine september 1996 7 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) with external rotation o f the hip.34 it is also aggravated by walking, kicking, jumping,17 sit -ups"'' and a sudden change o f running direction.17 coughing and sneezing may also increase the pain.2*’ the pain is relieved by rest.1'17'84 a sen­ sation o f clicking might b e present, usually indicating a degree o f instability o f the pubic symphysis.717 physical signs t h e m ost important clinical sign o f traumatic osteitis pubis is that o flo ca lis e d tenderness over the symphysis pubis and the adjacent pubic bones.1'417 20 26 28 tenderness may also be present at other sites including the ischiop ubic rami,17 pubic tubercles,26 pelvic insertion o f the rec­ tus abdominus m uscle,28 adductorm uscle heads,2028 gra­ cilis insertion25 and over the inguinal ligam ents.'6 rectal and prostate examination may produce tenderness ante­ riorly, due to pressure transmitted to the overlying pubic symphysis.26 pain can also b e elicited by the following movements: forced abduction with external rotation, thereby putting the adductors under strain17 24 forceful adduction against resistance25'262830 active contraction o f the rectus abdominus m uscle3628 further physical examination may reveal biom echanical abnormalities including leg length discrepancies, varum alignment o f lower extremities, impaired hip mobility and weak hip and abdominal muscles.20 special investigations radiology t h e suggested views that will assist in the diagnosis o f traumatic osteitis pubis are the i) antero-posterior, lat­ eral, and oblique views o f th e pelvis,-4-0"7"” ii) single leg weight bearing views,1727 and iii) special views o f the sacro-iliac joints.20 27 r ep orted radiological features that have been described in association with traumatic osteitis pubis include the following: normal radiology35'30 because it may take up to 4 weeks for radiological changes to b ecom e evident. destructive changes including osteolytic lesions and erosions in the symphysis.2428 t h e osteolytic changes in the os pubis and ischia may b e evident around the insertions o f the gracilis and adductor longus and brevis, unilaterally or bilaterally.-4 abnormal w idth o f the symphyseal cleft, with 10mm described as the upper lim it o f normal.417'26 marginal irregularity o f the symphysis.4'17 25'28 '10 reactive sclerosis o f the pubic bones at the symphy­ seal margins are described.417'25'20'28'30 reactive sclero­ sis o f the iliac com ponent o f the sacro-iliac joints has also been d escribed in association with trau­ matic osteitis pubis.17 instability o f the pubic symphysis demonstrated by single leg weight bearing views.1728 a difference in height o f the superior pubic ramus on each side o f more than 2mm has b een regarded as abnormal.17 accentuation o f th e origins o f the gracilis m uscle in patients with pubic symphysis has been reported. asymmetrical erosions o f the symphysis and bone frag­ ments at the bony origin o f the gracilis muscle have been reported.25 it is essential to investigate the sacro-iliac joints along wit h the symphysis pubis, as both the sacro-iliac joints and the symphysis pubis may b e involved in the same pathological process, or conversely, instability o f either sacro-iliac joints or symphysis pubis may result in pathology o f the other.17'27 28 b one scan the triple phase technet ium bone scan finding in trau­ matic osteitis pubis is usually that of bilateral increased uptake.14 20 38 30 positive bone scans in clinically diagnosed cases o f traumatic osteitis pubis have been reported in the presence of normal x-rays. it is suggested that bone scans can b e used to confirm early subtle forms o f osteitis pubis before changes are evident on convention­ al radiography.30 bone scans can also b e useful to differentiate trau­ matic osteitis pubis from local soft tissue injuries, pelvic stress fractures,4 and adductor tendon avulsions. angular and pelvic outlet views are suggested to avoid the bladd er shadow7.28 other special investigations magnetic resonance imaging scanning o f the pubic sym­ physis m ight b e useful in patients with traumatic osteitis pubis. isokinetic m uscle strength testing of the hip m uscles may also reveal important aetiological fac­ tors in this condition and ’will provide a basis for reha­ bilitation o f this injury. management and rehabilitation treatment o f sym ptoms r est is the b est treatment to relieve the pain o f osteitis pubis.4 172428'30 m ost authors advocate a period o f rest which can vary from weeks to m onths.417-4'30"10 recovery may b e expedited with th e addition of anti-inflammato­ ry drugs. t hese drugs m ust b e used regularly.17''’0 -'’ 30 the use o f local anti-inflammatory therapy is controversial. local hydrocortisone injections have been used success­ fully,33 30 but should b e avoided unless the person admin­ istering it is experienced. care must b e taken to avoid the possibility o f infection.17 high doses or oral corticos­ teroids have also been reported as being effective in treating athletes with osteitis pubis.37 local infiltration o f the painftil area with 5-10m l of 0,5-1% xylocaine is helpful to relieve the pain, and can also b e used as a diagnostic test for this condition.34 however, a major limitation in recom m ending the m ost effective local treatment for this condition, is the lack of controlled tri­ als. this area requires attention. identification and correction o f underlying causes. limited data are available on the m ethods of identifying and correcting the underlying causes o f traumatic osteitis pubis. restoration o f hip join t m obility has been p roposed,20 33 and strengthening exercises o f all the groin m uscles are recom m ended as important factors in the rehabilitation o f patients with this condition..-0-4 correction o f any biom echanical abnormalities is an essential com ponent o f the management. again, no con ­ trolled clinical trials have b een published to evaluate the efficacy o f these corrective measures. 8 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) overuse injuries of the h ip join t a detailed discussion of overuse injuries o f the hip joint are beyond the scope o f this article. however, the hip joint, in particular degenerative osteoarthritis o f the hip joint, can m im ic many o f the overuse injuries that pre­ sent with hip and pelvic pain. t he attending doctor should be aware that osteoarthritis o f the hip can cause pain and stiffness, and investigate the athlete appropri­ ately. certain sports may predispose the athlete to osteoarthritis o f the hip join t (table 4). table 4: sports predisposing to osteoarthritis o f the hip ballet gymnastics running soccer track and field athletics racquet sports (a dap ted from paim sh 1990, viiigard 199 4) overuse injuries of the bones bone stress injuries o f the hip and pelvic bones will b e discussed in a separate article in this journal. overuse injuries of the soft tissues t he athlete with pain in the hip and pelvis region may also present with a chronic soft-tissue injury. these injuries are m ore com m on than bony overuse injuries and generally are easier to diagnose and treat. a few com m on chronic soft tissue injuries wall b e discussed. snapping h ip syndrome introduction the “ snapping hip syndrom e” refers to a condition in which athletes com plain o f hip pain associated with audible snapping during movement.38 this can b e a dif­ ficult diagnostic and therapeutic challenge and deserves attention. a etiology the precise aetiology is not known. traditionally the “ snapping” has been described on the lateral aspect o f the hip (external snapping). in these cases it has been attributed to the slipping o f either the thick posterior border o f the iliotibial band or the anterior bord er o f gluteus maximus over the greater trochanter. however, in recent years attention has also been focused on the so-called “ internal snapping h ip ” . h ere th e aetiology has been attributed to either the slipping o f the iliop­ soas tendon over the iliopectineal em inence or snapping of the iliofemoral ligaments over the anterior hip cap­ sule. other causes that have been listed are: ■ osteochondrom atosis subluxation o f the hip ■ loose b odies clinical diagnosis on history the patient complains o f hip pain associated with an audible snap a nd /or a palpable snapping sensa­ tion. t he pain is described as a dull ache. t he snapping can usually b e precipitated by extending the hip from a flexed , abd u cted and externally rotated position. specific activities such as ballet or jogging can som e­ tim es b e associated with th e symptoms. on examination there are no discreet areas o f ten­ derness but the snap can b e reproduced b y voluntary extension o f the hip join t from th e flexed, abducted, externally rotated position. special investigations x-rays and hip join t arthrography are usually normal. iliopsoas bursography can demonstrate a sudden jerk ­ ing movem ent o f the iliopsoas tendon in a large p er­ centage o f cases. management initially conservative management is recom m ended. this includes altering the activity and possibly local steroid injection into the site. however, i f that fails, surgery is indicated. asymptomatic audible snapping is rarely an indication for surgery. snapping that is associ­ ated with pain and which does not respond to conserva­ tive treatment, is an indication for surgery. in one series m ost patients underwent surgery with exploration o f the iliopsoas tendon region. the following abnormalities were noted: tight iliopsoas tendon prominent iliopectineal eminence visible snapping o f the iliopsoas tendon (on repro­ duction o f th e movement) surgical procedures were perform ed to lengthen the iliopsoas a n d /or resect bony ridges on the pelvic brim. chronic muscle injuries c hronic m uscle injuries o f th e hip and pelvic m uscula­ ture are com m on. t h e m ost com m on m uscles to b e affected are gluteus m edius, ham strings, iliopsoas and the adductor m uscle group. t he m echanism o f injurv is either repetitive overload with m icroscopic tearing or secondary to scar formation following an acute m uscle strain. clinically th e athlete will present with pain p ro ­ gressing from g rade i to iv for overuse injuries. the site o f pain is localised to th e m uscle involved and is aggravated by m ovem ents requiring contraction o f that m uscle. t h e diagnosis o f a chronic m uscle tear can b e in th e p resence o f one or m ore o f the following clinical signs: localised tenderness in the m uscle belly restricted range o f motion o f the m uscle pain on passive stretching o f the m uscle pain on restricted contraction o f th e m uscle in m ost cases it is not necessary to confirm th e diagno­ sis using special imaging techniques. however, these lesions can b e dem onstrated on magnetic resonance imaging scans. isokinetic muscle strength testing will show a strength deficit in the affected muscle, and this is useful to monitor progress during rehabilitation. t h e management o f chronic m uscle injuries is to decrease and alter the scar tissue, increase flexibility o f the muscle, deep transverse friction and correcting m us­ cle strength d e ficits / ’ this is b est perform ed by a phys­ sports medicine september 1996 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) iotherapist followed by a m uscle rehabilitation under the guidance o f a biokineticist. t h e rehabilitation pro­ gram m e should include eccentric contraction training. entrapment neuropathies around th e h ip and pelvis. p iriform is syndrom e t h e p iriform is syndrom e refers to a nerve com p res­ sion syndrom e rather than a ch ron ic m uscle tear although ch ron ic tears can obviously occu r in this m uscle. t h ere are many known anatom ical variations in th e relationship betw een th e piriform is m u scle and th e sciatic nerve. d ecrea sed flexibility' in the m u scle can som etim es cause com p ression o f th e s c i­ atic nerve w hich results in pain. t h e a th lete presents w ith hip and b u ttock pain w hich is aggravated by m ovem ents requiring external rotation o f th e h ip jo in t (stretchin g th e p iriform is). t h e d iagn osis can b e c o n ­ firm ed by m r i im aging o f th e piriform is and th e s c i­ atic nerve using special views. m anagem ent is by m ob ilising th e piriform is m us­ cle , neural stretch in g and rehabilitation. t h e use o f loca l anaesthetics and cortison e injection is con tra­ ind icated. o rth otics that prevent excessive subtalar jo in t pronation m ay b e useful as th e com pensatory internal fem oral rotation that a ccom panies excessive pronation causes eccen tric contraction o f th e p iri­ form is m uscle. surgical relea se is required i f all oth er m easures o f conservative treatm ent fail. lateral fem oral cutaneous nerve t h is injury is p erh a p s th e m ost com m on nerve entrapm ent around th e hip and p elvis region in letes. it is also known as “ m eralgia p aresth etica ” .40 a th letes p resen t w ith altered sensation over the an terola tera l a s p e ct o f th e th ig h . it is a w ell d e sc rib e d con d ition in w eigh t lifters as a resu lt o f tight b e lts or corsets, and in gym nasts im pacting their h ip s and thighs on parallel bars. in th ese ca ses d ealing with th e underlying cause b y avoiding im pact, or tight com pression, h as a good prognosis. r arely a loca l anaesthetic b lo c k is necessary, and surgery is generally n ot req u ired as th is is a con d ition o f a superficial nerve that is purely sensory. fem oral nerve fem oral nerve entrapm ent can result from repetitive flexion and extension o f th e trunk in sports such as dancing, gym nastics, ju d o , and parachuting.10 t h e site o f th e entrapm ent is assum ed to b e w here th e nerve p asses under th e inguinal ligam ent. isola ted fem oral n europathies p rod u ce w eakness during kn ee exten­ sion and a d e p ressed knee reflex. t h ere will a lso b e sensory loss over th e anterom edial asp ect o f the thigh. e lectrom yography (em g) is useful to d ifferen ­ tiate isola ted fem oral neuropathy from m ore proxim al lesion s (lum bar ro o t lesion ). involvem ent o f the lu m ­ bar root will also p rod u ce w ealaiess o f th e h ip flexors (iliop soas). m anagem ent is conservative, and will inclu d e avoiding th e m ovem ents d escrib ed , m uscle strength training o f th e qua d ricep s m uscle, and m ain­ taining range o f m otion o f th e h ip join t. surgical relea se may also b e con sid ered i f sym ptom s persist. gluteal nerve entrapment o f the superior gluteal nerve has also been d escrib ed as a cause of ch ron ic gluteal pain. the diag­ nosis can b e confirm ed 0 11 emg. conservative treat­ m en t con sistin g of stretch es, and m ob ilisa tion . surgical release may b e indicated.40 p osterior cutaneous nerve entrapment o f d ie posterior cutaneous nerve oi the thigh has b een d escribed in a cyclist. t h e presentation is that o f p aresthesia in the distribution o f the nerve (lower buttock and posterior thigh). pudendal nerve pudendal nerve entrapment has b e e n d escribed in cyclists and is due to p rolonged sitting on an incorrect saddle. sym ptom s inclu de num bness and d ecreased sensitivity' in th e lateral aspect of the genital area (penis and scrotum in males, and labia in fem ales). o bturator nerve obturator nerve entrapment is an uncom m on condition presenting with w eakness o f hip adduction, and pares­ thesias 0 1 1 the inner thigh. t h e diagnosis can b e con ­ firm ed by emg, and surgical release is th e m ost effec­ tive treatment.41 chronic bursitis in the region of th e hip and pelvis trochanteric bursitis trochanteric bursitis is not as com m on as is p e r ­ ceiv ed and p robably m ost ca ses th at have previously b e e n d ia gn osed as trochanteric bursitis w ere in fact ch ron ic m u scle injuries. trochanteric bursitis can occur in eith er the superficial (m ore com m on ) or the d eep troch an teric bursa. t h e pathology o f superficial trochanteric b ursitis is th ou gh t to b e sim ilar to that o f iliotibial b an d friction syn drom e and is related to th e repetitive rubbing o f th e iliotib ia l band on the greater trochanter. t h is results in inflam m ation in th e area. clinically th e athlete presents with lateral hip pain associated with running (repetitive hip flexion and extension). t h ere is point tenderness over the greater trochanter and pain can b e reproduced by a repetitive hip extension flexion m ovem ent.38 it is im portant to assess for biom echan ical abnorm alities such as. tight itb (o bers test) w ide h ip s/p elvis genu varus leg length discrepancy forefoot and rearfoot abnorm alities management is conservative and sim ilar to that o f iliotibial band friction syndrome. ischial bursitis inflammation o f the ischial bursa can b e as a result ol p rolonged sitting, or d irect trauma to the bursa. clinically there may b e tenderness and swelling over the bursa.38 management is to reduce th e -inflam m a­ tion, avoid the irritating factors, and surgical treat­ m ent may b e necessary in refractory cases. 10 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) iliopectineal bursitis iliopectineal bursitis presents with anterior groin pain and is often accom panied by an antalgic gait.38 on examination there is pain on deep palpitation o f the iliopsoas tendon and th e pain is aggravated on hip flex­ ion and external rotation. there may b e swelling and accompanying irritation o f the fem oral nerve. t h e d iag­ nosis can b e confirm ed by mri scanning. sym ptomatic treatment may b e beneficial but i f there is a large swelling with accompanying neurological signs, surgi­ cal decom pression is necessary. chronic tendinopathies around the h i p and pelvis introduction chronic tendinopathies around the hip and pelvic region can give rise to ch ronic pain. t h e pathology o f these conditions may vary from peritendinosis to d egen era tive tendinopathy. in gen eral, ch ron ic tendinopathies are caused byr repetitive overload o f the ten d ons th iou g li vigorous contraction or passive stretching of the m uscles. recently, diagnostic ultra­ sonography has b een suggested as a valuable m ethod to diagnose th ese lesions.4’ a few o f the m ore com m on sites for chronic tendinopathy around the hip and pelvis will now b e discussed. chronic adductor tendinopathy chron ic tend inopathy o f the adductor group o f m uscles is com m on in soccer players, h ockey players, ice skaters, breast stroke swim mers, rugby players, and cricket players (bowlers). t he m echanism o f injury is repetitive forceful contraction o f m uscles o f the a d d u c­ tor group. patients present with unior bilateral groin pain. t h ere is tenderness over the adductor tendons ju st distal to their origin from the pubic ramus. t h e pain can b e precipitated by passive stretching or resist­ ed contraction o f the adductor m uscle groups. initial treatment is to decrease th e inflanunation, and this is followed by stretching, strengthening th e adductors and a gradual return to activity.*' isokinetic m uscle strength testing m ay b e useful to m onitor progress dur ing the rehabilitation process. chronic rectus fem oris tendinopathy the rectus fem oris m uscle functions as a hip flexor, and as an extensor o f the knee. r epetitive activity o f the rectus fem oris m uscle, such as during running, can cause a chronic injury to the tendon attachm ent o f the m uscle to the anterior inferior iliac spine. athletes, often distance runners, present with anterior groin pain d m in g running. clinical examination reveals ten­ derness over the tendon with pain in th e region during passive stretching and resisted contraction o f the muscle. management is by conservative treatm ent consisting o f m easures to d ecrease th e inflammation, stretching and strengthening the m uscle and gradual return to activity. chronic iliopsoas tendinopathv chronic iliopsoas tendinopathy can be caused by repet­ itive contraction of the hip flexors (iliopsoas), or repet­ itive stretehing o f this m uscle during h ip extension such as in gymnasts. t h e patient will present with anterior groin pain w h ich is aggravated by resisted hip flexion or forced passive hip extension.44 this injury can b e associated with iliopectineal bursitis and can cause irritation o f th e femoral nerve. treatment is con ­ servative in the first instance. occasionally surgery is required to im prove b lood supply to a degenerative tendon. oth er soft tissue injuries injuries to the con join t tendon/inguinal canal t h e conjoint tendon is formed by the com m on inser­ tion of the rectus abdom inis m uscle, th e internal oblique m uscle, and the transversalis fascia onto the pubic tubercle. it extends along th e superior surface o f the superior pubic ramus and forms part o f the p oste­ rior wall o f th e m edial end o f the inguinal canal. repetitive traction resulting from kicking can produce a num ber o f different pathologies in this region. this syndrom e is also known as “ g ilm ore’s groin” . the pathology o f this condition can b e i) a tear o f the attachm ent o f the tendon at the pubic tubercle,45 ii) a tom external oblique aponeurosis causing dilatation o f the superficial inguinal ring,4" or iii) d e h is ce n ce between the inguinal ligam ent and th e torn conjoint ten don.w patients p resent with groin pain that typically, radi­ ated into the rectus abdom inis or along the inguinal ligament. aggravating factors are kicking and turning. t h ere is exquisite tenderness at th e site o f th e conjoint tendon or the superficial inguinal ring. pain can be reproduced by coughing and sneezing. investigations such as x-rays, bone scan and mri scan generally are not helpful to diagnose this condition. h emiography, technically difficult, can b e used to dem onstrate w eak­ ness o f the m ed ial posterior wal 1 o f th e inguinal canal. management is difficult and often surgery to repair the tear and strengthen th e posterior inguinal wal 1 has to b e con sidered.4*’ 47w chronic overuse injuries of the grow th plates around the h ip and pelvis region. introduction traction apophytsitis sim ilar to that occurring at the tibial tubercle (o sgood-schlatter) have been described in the pelvic bone. t h e m ost com m on site is th e iliac crest (iliac apophysitis) followed 1 >v the anterior supe­ rior iliac spine. t h e focus o f this section will therefore b e on iliac crest apophysitis. aetiology/mechanism of injury t h e m echanism s o f injury is sim ilar to that for apophysitis in other regions. excessive repetitive force application to the ossification center o f the area involved is the likely cause. t h e ossification center for the iliac crest first appears anterolaterally and then advances until it reach es the posterior iliac crest. the average age o f closure o f th is ossification center is d if­ ferent in boys (16 years) and girls (14 years). in iliac crest apophysitis the force is generated by the contraction o f th e oblique abdom inal m uscles, ten­ sor fascia lata and gluteus m edius. e xcessive rotation sports medicine september 1996 11 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) o f th e pelvis during running may increase the risk o f injun7 ('as in athletes with excessive cross-over arm swings). clinical diagnosis t h e athlete w ho is usually in h is /h e r m id or late teens presents with loca lized pain over th e iliac ciest. this may only occur w hile running. t h e localization of the pain may b e anterior or m ore posterior on the iliac crest. on examination there is tenderness over th e iliac crest and the pain can b e rep rodu ced on resisted con ­ traction o f the affected m uscle (eg. hip abduction glu­ teus m edius). special investigations in general it is advisable to x-ray the affected area to exclude fractures. m anagement t h e m anagem ent is conservative with ice, stretching, phvsiotherapv and alteration o f activity for 4 to 6 w eeks. attention can b e given to altering running style (excessive arm swinging) it necessary. o th e r overuse injuries of th e h ip and pelvis in adolescent athletes t h e a dolescent athlete w ho presents with hip pain m ust b e con sidered as a special group. in addition to th e injuries that have already b e e n d iscussed the child w ith a painful hip m ust b e a ssessed carefully to exclude other pathology. a few o f the other causes o f hip pain in th is group will b e considered. p erth e’s disease t h is is a d isea se o f the younger ch ild (4 -8 years) and is m ore com m on in m ales than fem ales.'"’11 t h e a etiol­ ogy is related to shift in p red om in an t b lo o d supply from th e m etaphyseal vessels (up to 4 years) to the vessels running in th e ligam enttim teres (frilly d ev el­ op e d by th e age o f 7 years). between the ages of 4 to 7 years th e b lo o d supply is d ep en d en t on lateral e p i­ p hyseal vessels. t h ese vessels w h ich are su sceptib le to pressure in th e jo in t w h ich can increase as a result o f n o n -s p e c ific in fe ctio n , sy n ovitis or traum a. interruption o f th e b lo o d supply then causes avascu­ lar n ecrosis o f th e fem oral head. t h ree stages of the con d ition have b e e n iden tified accord in g to the p ro ­ gression o f th e d isea se and x -ray findings. t h e clin i­ cal p resentation is th at o f a ch ild w ith a painful lim p. on exam ination th e hip m ay b e norm al with slight m u scle w7asting. r ange o f m ovem ent can b e norm al in th e early stage w ith abduction in external rotation usually th e first to decrease. x-ravs are required to m ake the diagnosis. t h e signs v ary with th e age o f the ch ild , the stage o f the disease and the amount o f the head that was ischaem ic. four groups have b een d escribed :4 ’ i: no collapse, < 50% o f h e a d ischaem ic ii: no collapse, > 50% o f h e a d ischaem ic i l l: collapse, < 100% o fh e a d ischaem ic iv: collapse, 100% o f h e a d ischa em ic management for the “ irritable h ip ” that is the sym pto­ m atic hip, is bed rest with traction until sym ptom s subside. further treatment is controversial, but gener­ ally varies from 1 1 0 intervention (group i and ii) to con ­ taining the head in th e acetabulum (abduction plaster or osteotom y) for groups iii and iv. slipped upper femoral epiphysis slipped upper femoral epiphysis refers to a d ispla ce­ m ent o f th e growth plate resulting in coxa vara. it can occur suddenly (30% o f cases) or gradually (70%). the m echanism o f injury7 is trauma t hat is associated with an underlying abnormality. trauma can b e a minor hip “ sprain” or a su dd en fall. underlying causes are anatomical (the growth plate b ecom es increasingly oblique during grow th) or horm onal (growth spurt). it is im portant for th e sports physician not to miss the gradual slip o f the upper femoral epiphysis in an adolescent athlete. t he essentials o f the clinical p re­ sentation are: age in b oys is usually 15 years (girls 12 years) 60% o f patients are overweight and sexually under­ developed 50% have a history o f a hip “ sprain” groin pain associated with exercise is th e com m on ­ est presentation shortening may be present the leg is often externally rotated the affected greater trochanter may b e higher and more posterior there may b e loss o f range o f m ovem ent (usually abduction and internal rotation) m uscle wasting may be present x-ravs are im portant to confirm the diagnosis. the main features are: a nteroposterior view: a line along the superior surface o f the femoral neck passes over the h ead (normally passes through the h ead ) (trethowan’s sign). the m etaphysis is lateral to th e posterior acetabular margin; norm ally th e posterior acetabular margin cuts across th e m edial c o m e r o f the upper fem oral m etaph­ ysis (capener’s sign). lateral view: deform ity is usually obvious from the beginning; the head and neck are angulated. t h e managem ent is surgical with pinning alone (minimal displacem ent) or reduction follow ed by inter­ nal fixation (unacceptable displacem ent). t h e sudden slip presents as a fractured neck o f the femur. t h e m anagem ent is reduction and internal fixation. t he com plications o f this condition are: coxa vara avascular n ecrosis osteoarthritis ch on d rolj’sis bilateral slipping (in 15-30% o f cases there is slip ­ ping o f the other hip in th e first 2 years after the first injury7) 12 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) other conditions of the hip and pelvic region in children t h e following is a list o f other conditions o f the hip and pelvis in the ch ild that m ust b e considered: viral synovitis juvenile suppurative arthritis suppurative juxta-articular osteom yelitis system ic d isord ers (acute rheumatic fever, juvenile rheumatoid arthritis, leukaem ia, sickle cell disease, tuberculosis, psoriasis) bone cysts and tumors references 1. lloyd-smith r, clement d b , mckenzie d c and taunton je: a survey o f overuse and traumatic hip and pelvic injuries in athletes. phijs sportsmed 1 9 8 5 ;1 3 (1 0 ):1 3 1 141. 2. d em en t d b et al. /i survey oj overuse running injuries. phys sports med 1980:8:47-58. 3. cibulka m t: rehabilitation oj the pelvis, hip and thigh. clin sports med 1 9 8 9 :8 ( 4 ) :777-803. 4. hold jf, bold b a : pubis stress symphysitis in a female distance runner. phys sportsmed 1986;14:61-65. 5. legue r. les cellulites periverticales et pelvienne apres certaines cystostomies en prostotectomies suspubiennes. j urol med chri 1923;15:1-11. 6. beer periostitis of symphysis and descending rami o f the pubis following suprapubic operations. int j med sura 1924;37:224-225. 7. conventry m b et a l osteitis pubis. j a m a 1961;dec ( 2 ) : 130-137. 8. bonza winston dj, hewitt wl. infectious osteitis pubis. urology 1 9 7 8 ;1 2 (6 ) -.663-669. 9. k arpos pa g , spindler kp, pierce m a , hull hj. osteomyelitis o f the pubic symphysis in athletes: a case report and literature review. med sci sports everc 1 9 9 5 :2 7 (4 ) -.473-478. 10. lane e l and chang iic. pubic and ischial necrosis following cystostom y and prostatectomy. a m j roentgenology 19 54:71:193-212. h beer periostitis and osteitis o f symphysis and rami o f pubes following suprapubic cijstostomies. j u roll928:20: 233-236. 12. kir/. e: osteitis pubis after suprapubic operation on bladder with report o f 10 cases. brit j sura 1946-34 272-276. 13. wheeler w k . periostitis pubes following suprapubic prostatectomy; results with deep roentgen therapy. a m j surg 1947;74:480-487. 14. muschar m. osteitis pubis following prostatectomy. j urol 19 45:54:447-458. 15. cibert j. postoperative o.p.: causes and treatment. brit j urol 1952;24:213-215. 1'6. steinbach hl, petrakis nl. gilfdan rs, smith dr. pathogenesis o f osteitis pubis. j urol 1955;74:840-846. 17. harris nh. lesion o f the symphysis pubis in women. b m j 1974:4:209-211. 18. scott dl. estmond cj, wright v a comparative radiolog­ ical study oj the pubic symphysis in rheumatic disorders. a n n rheum d ls 1979;38:529-534. 19. hollander jl, mccarthy d l : arthritis and allied condi­ tions. a textbook o f rheumatology. philadelphia l e a and tebiejer 1972 ;p l39 9. 20. fricker pa, taunton ■ i a m m a n n w. osteitis pubis in athletes. sports med 1 9 9 l ;1 2 ( 4 ) -.266-279. £1■ wiltse ll and franc ci1. journal o f bone and joint surgery 19 56 ;38 a :500 . 22. tlowse a jg . proceedings o f the royal soc o f medicine. 1954;57:88-90. 23. murray and jacobson: the radiology o f skeletal disorders. london, churchill livingstone 1971. 24. smodlaka vn. groin pain in soccer players. phys sportsmed 1980;8:57-61. 25. james jw. traumatic osteitis. the gracilis syndrome. a m j sportsmed 1983;11:363-366. 26. hanson pg, angevine m, juhl jil osteitis pubis in sports activities. phys sportsmed 1978;o ct (4 ) -.111-114. 27. liebert pl, lombardo ja , belhoek gh. instability in an athlete 28. zimmerman g: groin pain in athletes. a u st fam phys 1988;17:1046-1052. 29. sing r, cordes r, siberski d. osteitis pubis in the active patient. case report. physic sports med 1 9 9 5 :2 3 (1 2 ) ■ 67 73. 30. koch r, douglas wj. pubis symphysitis in runners. a m j sportsmed 1981;9:62-63. 31. batt me, mcshane jm, dillingham mf. osteitis pubis in collegiate football players. md sci sports exerc 1995-27 (5)-.629-633. 32. williams jgp, sperryn pn. sports medicine edition 2. baltimore, williams and wilkens co 1976;pp432-434. 33. williams jgp. limitation o f hip joint movement as a factor in traumatic osteitis pubis. brit j sportsmed 1978;12:129 133. 34. a dam s rj, chandler f a : osteitis pubis o f traumatic etiology. j bone joint surg 19 53;35a (3 ) -.685-695. 35. pierson e l. osteochondritis oj the symphysis pubis. surg gyn and obstet 1929;49:834-839. 36. holt m a . james sk. graf bk , ilelwig dc. treatment o f osteitis pubis in athletes. results of corticosteroid injec­ tions. a m j sports med 1 9 9 5 ;2 3 (5 ) -.601-606. 37. pyle l a . osteitis pubis in an athlete. j a m col health association 1 9 75;23:238-239. 38. sim fii, rock mg, scott sg. pelvis and hip injuries in ath­ letes: anatom y and function. in: the lower extremity and spine (second edition) 1996. nicholas ja , ilershman ed (ed). mosby, new york p p l0 2 5 -1 0 6 5 . 39. karlsson j, sward l, kalebo p, tliomee r. chronic groin injuries in athletes. recommendations for treatment and rehabilitation. sports med 19 94 ;17 (2)-.141-148. 40. spindler kp. pappas j. neurovascular problems. in: a natom y and function. in: the lower extremity and spine (second edition) 1996. nicholas j a , ilershman ed (ed). mosby, new york p p l3 4 5 -1 3 5 8 . ^1bradshaw c, mccrory p. a review of twenty cases o f obturator entrapment neuropathy as a cause o f groin pain. med sci sports exerc 1996;suppl 2 8 (5 ) 5 6 (3 3 ). 42. kalebo p, karlsson j, sward l, peterson l. ultrasonography of chronic tendon injuries in the groin. a m j sports med 1 9 9 2 ;2 0 (6 ) -.634-639. 43. martens m a , hansen l, mulier jc. adductor tendinitis and muscular rectus abdominus tendopathy. a m j sports med 1 9 8 7 :1 5 (4 ) :353-356. 44. weiker gg, mannings f. selected hip and pelvis injuries. phys sportsmed 1 9 9 4 ;2 2 (2 ) :96-106. 45. bloomfield j, fricker pa, filch k d (ed). textbook o f science and medicine in sport. blackwell scientific publications, 1992. 46. williams i! foster me. “gilmore’s groin” or is it? b r j sports med 1 9 9 5 ;2 9 (3)-.206-208. 4 / . lovell g. conjoint tendon injury the sportsman’s hernia. proc sports med sem, australian sports medicine federation (s a ) 1990. 48. taylor dc, meyers wc, moylan ja , bassett f k , garrett we. abdominal musculature abnormalities as a cause o f groin pain in athletes. a m j sports med 19 91;19 (3 ):2 3 9 242. n sports medicine september 1996 13 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) stress fractures and bone stress injuries of the hip and pelvis dr ew derman mbchb phd facsm dr m p schwellnus mbbch md facsm introduction stress fractures and b on e stress injuries o f th e hip and pelvis encom pass stress injuries o f the femoral neck, sacrum, ilium, ischium and pubic bone. many term s have b een interchangeably with “ stress fractures including march fractures, insufficiency fractures and fatigue fractures, and therefore controversy7 exists regarding the term “ stress fracture” . a stress fracture can b e d escribed as a m icrofracture o f bony tissue w hich occurs as a result o f either i) excessive load cy cles (number, duration, frequency) p la ced upon norm al bone; or ii) normal load pla ced on suboptim al or weak b o n e .1,2'3 we prefer jones term b one stress reaction” as th e term used to d escribe th e continuum o f changes in b one, from rem odelling to a frank fracture4 and th erefore th is term w ill b e u sed throughout this review. t h e grading o f b one stress injury according to th e pathology, clinical symptoms, x -ray and bone scan findings is shown in table 1. all b on e stress injuries o f th e hip and pelvis can present in the athlete as persistent hip and groin pain. although they are fairly uncom m on overuse injuries, there are special considerations, including prolonged disability and p ossible com plications o f a displaced fracture (in th e case o f the fem oral n eck stress fracture), w hich m ake th ese injuries im portant to diagnose early. however, b on e stress injuries are often difficult to diagnose and can b e frustrating to treat. incidence b one stress injuries com prise approximately 10% o f sports injuries and are m ore commonly7 seen in athletes participating in w eight bearing sports.3*’ bone stress injuries o f th e femoral n eck are unusual but not rare injuries in athletes.78 t hey account for approximately 5% o f all b on e stress injuries.9 bone stress injuries o f th e pelvis are rare and com prise only approxim ately 1.25% o f all b one stress injuries. t h ese injuries are found m ost frequently in long distance runners and generally occur at the inferior pubic ramus / ischium junction, near the symphysis pu b is.101112,13 w hilst bone stress injuries o f the sacrum have been associated with bony insufficiency in th e non-athletic population,1415 few reports o f sacral b one stress injuries in athletes, exclusively runners, exist in th e m edical address for correspondence: dr ew derman sport science institute o f south africa, p o box 225, newlands, 77 25 south africa. literature.161718 however, this injury7 is probably m ore com m on than its lack o f docum entation suggests. only isolated cases o f b one stress injuries o f the os ischium and th e acetabulum have b een rep orted , m ostly occurring in osteoporotic b on e.19 -0 aetiology and pathology t h e detailed principles o f the aetiology7 and pathology o f b one stress injuries and stress fractures have been previously7 review ed4' 1 and are bey7ond the scope o f th e present review. r isk factors for stress fractures and bone stress injury: fem ale gender;23 caucasian race;24 increasing age;24 insufficient dietary7 calcium intake;'5 history o f am m enorrhoea;25 20 insufficient ca loric intak e/eating disorders; p oor physical fitness;27 intense or prolonged w eigh t b ea rin g activity428 and b io m e ch a n ica l abnorm alities.829 identical principles governing the aetiology7 and pathology o f the m ore com m on bone stress injuries o f the lower lim b, apply to the b one stress injuries o f the hip and pelvis. however, th e special classification o f femoral n eck b on e stress injury, particularly stress fractures o f th is area, based on th e m echanism and site o f injury, d eserves m ore attention. bone stress injuries o f th e fem oral n eck occur in distance runners, dancers, military recruits, hurdlers, football, soccer and rugby play7ers and cross country skiers. t h e proxim al femur is subject to loads o f up to six tim es b o d y w eigh t during walking with high com pressive loads occurring on concave sid e o f the femoral neck and tensile load s on the convex side. loading increases substantially during running.so t h ree classification system s have b een p roposed for stress fractures o f th e femoral neck.2-9 31 all th e system s incorporate th e biom echanical nature of the injury7 and fracture displacem ent. t h e classification by fullerton and snowdy (19 88 ) is the m ost popular: a) compression stress fractures: t h ese refer to undisplaced stress fractures on the com pression s id e o f the n eck of the femur (inferior side, located at th e cortex o f th e lower m edial margin o f the fem oral n eck ) and are m ore com m on in young athletes.32 t h is fracture seld om displaces unless stress continues. fractures can vary in t heir staging according to x-ray and b on e scan findings. t he spectrum o f injury starts with a negative x-ray b u t positive b one scan (com pressive sid e, stage 1), followed by bony sclerosis w ith a bsen ce o f cortica l fracture (stage 2). t h is p rogresses to a cortical fracture and finally widening o f the fracture line (stage 3). b) tension fractures: t h ese refer to undisplaced stress fractures on the tension sid e (superior) o f th e femoral n eck and are m ore com m on in m ilitary recruits and elderly patients. 14 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) tension stress fractures have a worse prognosis than com pression stress fractures as delayed union, non­ union and avascular necrosis o f the femoral head are recognized com plications. early diagnosis is essential as th e consequences o f a delay in the initiation o f treatm ent may seriously affect the athletes career." t h e stages o f this injury are as previously indicated: p ositive b on e scan and negative x -ray (stage 1), endosteal or periosteal callus wit h no visible fracture line (stage 2), follow ed by a visible fracture line and finally widening of t he fracture w ithout displacem ent (stage 3). c) displaced fractures: this refers to fractures where there is com plete stress fracture displacem ent evident on x-rays. clinical presentation bone stress injuries o f the hip and pelvis can b e difficult to diagnose and require a high index o f suspicion. a careful history usually reveals a significant increase in training intensity, duration or frequency, or altered training footwear or running surface, preceding the onset o f pain. more unusual causes m ust b e sought including dietary and endocrine factors. in fem ale athletes, a b r ie f gynaecological history should b e obtained. common presenting symptoms and signs o f bone stress injuries o f the hip and pelvis are shown in table 2. bone stress injury in these regions usually causes the patient pain, which is the most common presenting symptom.5’ the pain is usually gradual in onset and develops during activity, m ost commonly running, or follow's a period o f increased training. the pain progresses until the athlete is unable to run or bear weight on the affected limb. nocturnal pain can be present. the pain is relieved by rest or non-weight bearing. fem oral neck t h e athlete with bone stress iryury o f the fem oral neck usually presents 6-8 w eeks after increasing training load, with pain in the region o f th e anterior groin. t he pain m ight radiate to th e thigh and knee. t here is often an antalgic gait and the athlete may not b e able to b ea r w eigh t on the a ffected lim b. physical examination may reveal swelling in the affected area, tenderness to d eep palpation or pain elicited by percussion or com pression of* the heel or th e greater trochanter. often there are no positive findings on physical examination b e sid e s pain at th e extrem ities o f hip jo in t movement. t h e different diagnosis should include a d d u ctor/iliop soas tendinopathy or m uscle tear, inguinal-femoral herniation, osteitis pubis, hip bursitis or synovitis and referred lum bosacral pain. table i: classil ication o f b one stress injury. m odified from j on es et al., 1989. grade 0 i ii iii iv n omenclature normal rem odelling m ild stress reaction m oderate stress reaction severe stress reaction severe fracture clinical signs and sym ptom s nil mild pain with or after activity7 not tender on palpation m oderate pain with activity m ild palpable tenderness severe pain with activity marked palpable tenderness and mass pain at rest m arked palpable tenderness and m ass x-ray findings negative negative positive/n egative positive positive b one sean findings n eg/p os positive positive positive positive table 2: sign/sympt clinical sii om ; / / = *ns and sym ptom s o f b on e stress injuries o f the hip and pelvis. ✓✓✓ = m ost com m on presenting com m on presenting sign/symptom; ✓ = less com m on presenting sign/symptom. persistent groin pain persistent posterior lumbar sacral pain pain radiating to diigh and knee nocturnal pain onset o f pain following long run or increased activity pain upon weight bearing on affected limb pain at extremes of range of motion antalgic gait pain oil deep palpation over injury femoral neck / / ✓ / / / ✓✓ s s s sacrum l4'1" / / / s s s s pubis "’•'a-13 / / ✓✓ ✓✓ s ✓✓ ischium / / ✓✓ ✓✓ sports medicine september 1996 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the saciiun a thletes with bone stress injuries o f the sacnun may present with persistent and progressive pain in the buttock, groin or sacroiliac regions following period of increasing or intense physical activity. on physical examination the patient may have an antalgic gait. d eep palpitation over the sacral and gluteal regions might elicit pain. patients with this injury usually have full range o f motion o f the hip, and examination of the lumbar" spine is usually n orm a l.1 d ilfeien tia l diagnosis includes sacroiliac join t pathology, gluteal and other hip m uscle injiuics, m etabolic bone disease and osseous neoplasms. the pubis and iscliiiuii athletes with bone stress injuries o f the pubis and ischium can also present, with a history of peisistent and progressive groin pain. on physical examination, pain may be clicitcd by d eep palpitation in the legion o f the inferior pubic ramus near the symphysis. weight bearing on the lim b on the side of the injiuy produces discom fort and pain (positive standing sig n ).1' pain may limit abduction and external rotation o f the hip. t he differential diagnosis should include abductor m uscle tendinopathy, adductor m uscle tear, osteitis pubis, trochanteric bursitis, tendinopathy and muscle tears o f the hamstrings, degenerative pathology of the hip and referred pain from the lumbosacral spine. special investigations laboratory m easurem ent o f alkaline p hosphatase, calcium , phosphorous and erythrocyte sedim entation rate have not proven helpful and therefore should not be routinely p erform ed .” x-rays are diagnostic in only' 30% o f cases and is a poor test to perform if (he primary aim is to diagnose a bone stress injury' o f the hip or p elvis.1’ however, radiography d o e s have a role in the initial investigation o f the athlete as bone tumours or other lesion s mav be e x clu d ed if the investigation is negative. som e authors advocate the use of follow-up radiographs 2-4 weeks after the diagnosis is made, to monitor cortical callus formation. the bone scan is nearly 100% sensitive for bone stress injury and is by far the best p io e c d u ie to perform for the diagnosis o f these injuries.** specificity is however poor, but the triplephase bone scan may improve the s p e c ific ity '7 this investigation may be positive as earlv as 6 to 72 hours after the onset o f the injury.™ i f the diagnosis o f a bone stress injury o f the hip or pelvis is suspected, we feel that this is one indication where more liberal use o f the bone scan is justified. examples o f positive bone scans in athletes with bone stress injuries of the pelvis are shown in figures 1, 2 & 3. magnetic resonance imaging (m ri) is beginning to gain acceptance as an im portant adjim ct in the diagnostic imaging of bone stress injuries, particidarly in the region o f the hip and pelvis.” 4" mri will often show abnorm alities within 24 hours o f the injury.41 li ad d ition , th ere is b etter soft-tissu e and bone resolution with mri com pared with bone scans.4' cost o f the investigation is h ow ever an im portant consideration. because o f its high definition, image clarity and axial vision, com puter tom ography reveals bone stress injiuics (gr iii-ho more effectively than traditional tomography and might be useful in imaging sonic femoral and tarsal navicidar bone stress in ju rie s /’ bone scan and mri remain the special investigations o f ch oice for the diagnosis o f bone stress injury of the hip and pelvis. a 11 t p e l v i s _____________________ ______ figure 1. bone scan image o f the anterior pelvis o f a long distance runner. the scan shows increased radioisotope uptake in the right sacroiliac region suggestive of a right sacral bone stress injury (g r il-i ii). there is also increased uptake in the right pubic bone (g r i). figure 2. bone scan image o f the posterior pelvis of a marathon runner. the scan sh ow s increased radioisotope uptake bilaterally in the sacroiliac regions suggestive o f bilateral bone stress injury. (right gr 111 iv. left gr ii-iii). 16 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ant m 0 % *■ % r> outlet figure ;i. b o n e scan im a g e o f th e p e lv ic ou tlet o f a sprinter. the scan s h o w s in crea sed r a d io iso to p e u p ta k e in th e left p u bic ra m u s s u g g e s tiv e o f a p u b ic h on e s tr e s s injury ( o r i l h l ) . management general principles o f management conservative management o f bone stress injuries is generally successful, but management b ecom es more aggressive as the grading o f the bone stress injurv increases. we feci that it is important that a m ulti­ disciplinary team is involved in (lie management o f the athlete with bone stress injury. the dietitian, sport psychologist, physiotherapist, biokincticist and coach all have important roles to play in the successful rehabilitation o f the athlete. the first important principle o f management in treating al] bone stress injuries o f the lower limb, is avoidance o fa ll activities which involve impact loading of the bone (and therefore cause pant). weight bearing can usually be maintained if it d oes not cause pain. i f pain is present at rest, it is often necessary to im m obilize the affected limb. analgesic agents and ice can be used in the uiitial management o f the athlete to decrease pain. u liilst the athlete must suspend the sporting activity which caused the bone stress injury, other 110 11 weight bearing ex ercises including cycling, aqua jogging, swim m ing and upper b o d y exercises arc en couraged. t h is will limit the phvsical deconditioning and psychological stress which can often accom pany bone stress injiuy. it is important that the athlete should be pain free during participation in any physical exercise undertaken during the period of rehabilitation. the second important principle o f management o f the athlete with bone stress injury is to identify and correct the risk factors d iscu ssed previously. in particular, inadequate dietary calcium intake and hormonal unbalances must be corrected if necessary. we are of the opinion that it is not possible to give the athlete an indication o f a specific period after which tunc normal sporting activity can be resum ed, as this varies greatly depending 0 11 the grading o f bone stress injury and individual variation in response to treatment. when the athlete has been pain free for 2-4 weeks; palpitation and percussion over the bone d oes not illicit discom fort; fidl weight bearing is normal and th cic is radiographic evidence of bone healing, (he athlete can gradually reliun to sport, using pain as the criterion for m onitoring recovery. t h e role o f electrom a g n etic current and h yperbaric oxygen theiap\ in the management of bone stress injiuy is still under investigation. surgical management is indicated if there is non­ union and p ersisten t pain d esp ite adequate conservative management. specific management ol femoral neck stress fractures the management of femoral neck grade iv bone stress injuries (stress fractiues) is more aggressive. the following treatment protocol has been suggested bv fullerton and snowdv (1988): c o m p r e ssio n t y p e str e ss fr a ctu re s: a. stage 1 (positive scan, negative x-rav): ( rutehes 11011 weight bearing followed bv gradual return to activity b. stage 2 (sclerosis): bed rest until the athlete is asymptom atic followed im­ partial weight bearing and gradual return to activity c. stage 3 (c rack but no widening): llosp ita liza tion and en forced bed rest (internal fixation if it is not practical) followed bv gradual return to sporting activity cl. stage 4 (( rack and widening): internal fixation. tension ty p e str e ss fr a c tu re s: the management of stages 1 to 4 is the same as for the com pression type. d isp la c e d str e ss fr a ctu re s: hie treatment of choice is em ergency reduction and internal fixation. c onclusion bone stress injuries o f the hip and p elvis arc uncommon injuries in the athletic population, and arc difficult to diagnose. a high index of suspicion o f these conditions is required, particularly iji the evaluation o f distance athletes who present with persistent, ill defined groin, hip or sacroiliac pain. bone scan and mri remain the “ gold standard" o f diagnosis. whilst con sen a liv e management by a m ulti-disciplinary team is usually effective for most bone stress injuries o f the hip and pelvis, som e stress fractures especially those of the femoral neck might require surgery. it is inipoi tant that risk factors for bone stress injury be identified and corrected to ensure that the injuiy d oes not recur. references 1. mcbryde am. stress fractures in athletes. ,\m ,1 sports med 1975:3:212-217. 2. uei'd.s mb. in: stress fractures. edinburgh: churchill lii ingstone. 1975:p i l:i. sports medicine september 1996 17 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) 3. lucas ts, einhorn ta. stress fracture o f the femoral neck during rehabilitation. arch physical med and rehab 1093; 74 ( 9 ) : 10041006'. 4. jones b h , harris jm, vinh tn, rubin c. exercise-induced stress f ractures and stress reactions oj bone: epidemiology, etiology and classification. in: pandolf k b (ed ). exercise and sport sciences reviews. a m coll sports med series. baltimore: williams and wilkins 19 89 ;1 7 :3 7 9 -4 2 3 . 5. mcbryde a m . stress fractures in runners. clin sports med 1985 ;4:7 37 -7 52. 6. hulkko a . orova s. stress fractures in athletes. internat j sports med 1 9 8 7 ;8 :2 2 1 -2 2 6 . 7. nielens ii. devogelaar jp, malghem j. occurrence o f a painful stress fracture o f the femoral neck simultaneously with six other asymptomatic localizations in a runner. j sport med p hys fitn 1 9 9 4 ;3 4 (1 ):7 9 -8 2 . 8. kupke mj, kohler dm, lorenzoni m il, edlich rf. stress fracture of the femoral neck in a long distance runnel, biomechanical cuspects. j emergency med 1 9 9 3 :1 1 (5 ). 58 7-59 1. 9. fullerton lr, snowdy iia . femoral neck stress fractures. a m j sports med 1 9 8 8 ;1 6 (4 ) -.365-377. 10. pavlov it. nelson tl, warren r f et al. stress fractures o f the pubic ramus. j bone joint surg 1 9 8 2 ;6 4 a : 1020-1025. 11. latshaw rf, kantner tr. kalenak a et at. a pelvic stress fracture in a female jogger. a m j sports med 1981 ;9:5 4-56 . 12. noakes td, smith j a , lindenburg g et al. pelvic stress fractures in long distance runners. a m j sports med 1 9 8 5 :1 3 :1 2 0 -1 2 3 . 13. setakovitch ik love l. stress fractures o f the pubic ramus. j bone joint surg 19 54 :36a :5 7 3 -5 1 6. 14. jones dn, wycherley a g . bone scan demonstration progression o f sacral insufficiency stress fracture. austral radiol 19 94 ;38 (2 ) -.148-150. 15. peris p. navasa m. guanabens n. monegal a , m oya f, broncos am , rimola a , munoz-gomez j. sacral stress fracture after liver transplantation. brit j rheumatol 1 9 9 3 :3 2 ( 8 ) -.702-704. 16. schils j. hauzeur jp. stress fracture o f the sacrum. a m j sports med 1 9 9 2 :2 0 ( 6 ) -.769-770. 17. atw ell e a , jackson dw. stress fractures o f the sacrum in runners. two case reports. a m j sports med 19 91 ;19 (5 ) -.531-533. 18. ilaasbeek jf, green ne. adolescent stress fractures o f the sacrum: two case reports. j pediatr orthop 1 9 9 4 ;1 4 ( 3 ) : 3 3 6-33 8. 19. smets c, r oos j, vanlommele, b u n k e r td. stress fracture o f os ischium. injury 1 9 9 5 :2 6 ( 6 ) :4 1 1-412. 20. lee ts, tong km, k u mc. insufficiency fracture o f acetabulum: a case report. chinese med j 1 9 9 5 ;5 5 ( 3 ) -.274-277. 21. kellam jf. fracture o f the pelvis and femur. in: torg js and shepard r j (ed it). current therapy in sports medicine ( third edition) 1 9 9 5 :4 6 8 -4 /3 . 22. sterling jc, edelstein dw . calvo r d , webb r. stress fractures in the athlete. diagnosis and management. review. sports med 1 9 9 2 ;1 4 (5 ):3 3 6 -3 4 6 . 23 . fullerton lr. femoral neck stress fractures. sports med 1 9 9 0 ;9 ( 3 ) -.192-197. 24. brudvig tjs, gudger td, obermeyer l. stress fractures in 29 5 trainees. a one year study o f incidence as related to aye. sex and race. j mil med 1 9 8 3 ;1 4 8 :6 6 6 -6 6 /. 25. myburgh k m , hutchings j. f a ta a ra b , hough sf, noakes td. low bone density is an aetiologic factor for stress fractures in athletes. a nn iht med 1 9 9 0 ;1 1 3 ( 1 ) :/5 4 -7 5 9 . 26. friedl ice, nuovo j a , patience th, dettori jr. factors associated with stress fracture in young army women: indications f o r further research. milit med 1992 -.1 5/ ( / ) ■ 334-348. 27. belkin sc. stress fractures in athletes. orthop clin north a m 1 9 8 0 ;1 1 :7 3 5 -7 4 2 . 98 ' kadel nj, teitz cc. k ron m alr a . stress fractures in ballet ' dancers. a m j sports med 1 9 9 2 ;2 0 (4 ) -.445-449. 29. james sl, b a tes br , osternig lr. injuries to runners. a m j sports med 1 9 7 8 :1 4 8 :6 6 6 -6 6 7 . 30. oh i, harris wti. proximal strain distribution in the loaded femur. a n in vitro comparison o f the distributions in the intact femur and after insertion o f different hip replacements femoral components. j bone joint surg 19 7 8 ;6 0 a : 75-85. 31. blickenstajj l d , morris jm. fatigue'fracture o f the femoral neck. j bone joint surg 1 9 6 6 ;4 8 a :1 0 3 1 -1 0 4 7 . 32. kaltsas ds. stress fractures o f the femoral neck in young adults. j bon e joint surg 1 9 8 1 :63 b :33 -3 7. 33. johnson aw, weiss cb. w h e e l e r dl. stress fractures o f the femoral shaft in athletes more common than expected. a new clinical teat. a m j sports med 1 9 9 4 ;2 2 ( 2 ) -.248-256. 34. leroi) r. fullerton jr. femoral neck stress fractures. sports med 1 9 9 0 :9 ( 3 ) : 192-197. 35. greaney rb, gerber fh. laughlin r l et al. distribution and natural history of stress fractures in us marine recruits. radiology 19 83 :1 4 6 :3 3 9 -3 4 6 . 36. sterling jc, webb rf, meyers mc, calvo k d . false negative bone scan in a female runner. med sci sports exerc 1 9 9 3 :2 5 ( 2 ) : 179-185. 37. rupani iid . holder le, espinola d a , semra ie. three phase radionuclide bone imaging in sports medicine. radiology 1 9 8 5 ;15 6:1 87-19 6. 38. matheson go, clement db, mckenzie d c et al. stress fractures in athletes. a study o f 3 2 0 cases. a m j sports med 1987 ;15 :46 -5 8. 39. rizzo pf, gould es, lyden jp, a sn is se. diagnosis o f occult fracture about the hip. j bone joint surg 19 9 3 :7 5 a (3 ) -.395-401. 40. keene js, lash e g . negative bone scan in a femoral neck stress fracture. a case report. a m j sports med 1 9 9 2 :2 0 (2 ):2 3 4 -2 3 6 . 41. martin sd. healey jii. horowitz s. stress fracture mrl. orthop 1 9 9 3 :1 6 ( 1 ) :/5 /8 . 42. reid js. joyner dm. misdiagnosis o f femoral stress fracture based on m r i scan: a c a s e report. clin sports med 1 9 9 0 ;2:8 3-89 . 43 . markey kl. stress fractures. clin sports med 1987 ;6: 40 5 -4 2 5 . d 18 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) rights, obligations and utility in sports medicine research s olivier ma (r h od es) university o f zululand abstract sports medicine is concerned with rehabilitation and perform ance in b oth elite and nonelite a thletes. continued research is crucial towards progress in these areas, and subjects are increasingly being subjected to manipulative and invasive experimental methods. in exam ining current research p ra ctices, this p a p er questions whether we ought to rank consequentialist principles over nonconsequentialist ones. the history o f cases of abuse o f human subjects is considered, and the argument is presented that official endorsement is not a sufficient guarantee against exploitation. the concept o f informed consent is examined in som e detail, and guidelines are presented as to when obtaining consent is deemed necessary. further, journ al review results seem to indicate that in a large number o f cases, consent is either not reported, or is not obtained. finally, the p aper discusses the use o f “ca p tive” subject populations, and here issues such as coercion and sanction are examined. whilst cautioning against an over-cautious approach to research ethics, the p ap er holds that researchers should be aware o f the potential for conflict between virtue and self-interest. finally, it is concluded that sports medicine researchers should be guided by deontologic rather than consequentialist ethical principles. sports m edicine and research sports m edicine is primarily concerned with the rehabilitation and perform ance o f both elite and nonelite athletes. both areas depend on research in order to m ake progress, and this research may b e either therapeutic or nontherapeutic, both form s (but particularly th e latter) contributing to im provem ents in sports perform ance. this paper focu ses on non­ th era p eutic resea rch in s ports m ed icin e, and evaluates the practice o f research eth ics in term s o f consequentialist and d eontologic approaches. r esearch per se is concerned with (usually) novel te ch n iq u es u sed to d ev elop or con trib u te to g en eraliza ble k n o w le d g e .1 r e se a rc h in sports address for correspondence: steve olivier hms department, university o f zululand, south afri ca tel: 2 7 351 9 3 9 1 6 e-mail: solivier@pan, uzulu. ac.za m edicine can b e seen to b e critical and exhaustive investigation th a t aim s, th rou g h system atic ob serva tion or exp erim entation , to e lic it new inform ation about human perform ance. from th is it follow s th a t w h ile p roced u res m ay b e rigorously evaluated and controlled, results and p ossible negative co n seq u en ces ca n n ot always b e accurately predeterm ined. r ecen t d eca d es have w itnessed a dram atic increase in research across disciplines, and sports m edicine is no exception. t h e com m only a cce p te d “ p ro g r e s s im p erative” view o f scie n ce d em a n d s th a t resea rch su bjects b e increasingly su bjected to m anipulative and p o ss ib ly invasive experimental m ethods. such procedures, w hilst increasing knowledge, may b e m aleficent, and it is necessary' to question w hether oturesearch ranks consequentialist principles over n on con seq u en tia list on es. r ifkincon ten d s that western m edical science continues to m ove towards utilitarianism. on the other hand, b rodie & st.opanr' state that current societal opinion reflects the present ethical b e lie f that it is m ore im portant to avoid risk to a subject than to gain future benefit or advance knowledge. t h ere is thus perhaps a need to examine w h eth er resea rch in s p orts m ed icin e p ra ctises bottom -line’ eth ics which is concerned only with winning and losing, or virtue ethics w hich is also concerned with how you play the game. the abuse o f human subjects h istory provides num erous chilling exam ples o f the abuse o f hum an subjects, such abuses com m only ju s t ifie d through a pp eals to th e b en eficia l consequences o f m edical research. space precludes going into detail suffice to say, that evidence exists reg ard in g th e harm ful exp loita tion o f resea rch subjects, such as th e tuskegee stud}7, experim ents on concentration cam p inm ates in nazi germany, and experim ents conducted by7 th e japanese on ‘prisoners of-war.m in som e cases utilitarian rationalisation p rotected researchers from prosecution, the argument being that the benefits to m ed ical science far outweighed the harm to a few individuals. t h e rationalisation behind this was that such valuable results were unobtainable elsew here due to m ore stringent controls. t hese ca s e s m entioned exem p lify extrem e exa m p les o f human subject abuse, but d o bring to the fore issues such as m aleficence and a d isrespect for subjects as persons. furthermore, a broad issue that ought to sports medicine september 1996 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) concern all researchers utilising human subjects is raised, namely that o f th e conflict between moral principles and s e lf interest. given the rise to prom inence o f b ioethics, it could b e argued that a repeat o f abuses m entioned above is not likely to occur. caution should how ever b e exercised b efore accepting such an argument, as progress dem ands, and society continues to encourage, hum an experimentation. an examination o f pre-world war ii germany shows that regulations on m edical ethics were com prehensive and protective towards subjects, yet physicians perpetrated abuses, indicating th at official endorsem ent is not a sufficient guarantee against exploitation o f human subjects. pettit" concurs with this, contending that self-regulation offers the m ost effectiv e p ro te ctio n for resea rch subjects. formalising ethical practices may thus b e a necessary, but not sufficient, condition for th e prevention o f subject abuse. i f this is accepted, then research involving human subjects n eeds to b e constantly reviewed and justified after consideration o f ethical principles such as resp ect for persons, beneficence, non m aleficence, ju s tice , veracity, fidelity, privacy, confidentiality and universalizability. inform ed consent in form ed c onsent is a controversial con cep t. d ifficulties with adequate com pliance exist, and critics contend that as generally understood and applied, it is o f lim ited value in protecting research subjects from p o s s ib le abuse. a d v oca tes for in form ed c on sen t however counter that research subjects are at present better protected than was d ie case in th e past, and that the im perfections o f d ie con cept should not necessarily result in us d iscarding the process. d espite debate about the m erits and adequacy o f the concept, th ere d oes nevertheless seem to b e con siderable consensus about th e moral im portance o f informed consent in western m edical research. inform ed consent has been d efin ed as th e knowing consent o f an individual ... able to exercise free power or ch oice w ithout inducem ent or any elem ent o f force, fraud, deceit, duress, or other form o f constraint or coercion .(i<|,vi> in the inform ed consent process, subjects m ust b e fully inform ed o f the risks, procedures, and potential benefits, and that they are free to end their participation in d ie study with no penalty whatsoever.' further, the com m unication p rocess in an informed consent context requires that ‘ ... it is given in th e full, or clear, realization o f what th e tests involve, including an aw areness ... o f risk attached to w hat takes place.*1’203’ when should inform ed c onsent b e obtained? a policy statem ent in m edicine & science in sports and exercise0*1’'0, states that ... any experim ental subject or clinical patient w ho is exposed to p ossib le physical, psychological, or social injury m ust give inform ed consent prior to participating in a proposed p roject.’ in addition, th e journal has a publication requirement w hich necessitates that authors take all appropriate steps in obtaining the inform ed c onsent o f any and all human subjects em ployed by investigators submitting m anuscripts for review7, and authors are required to indicate that consent was obtained. lastly, what elem ents should b e included in the construction o f an inform ed consent docum ent? kroll!k,,:ls> sum m arises a set o f b asic elem ents that ought to b e included in an inform ed consent docum ent as follows: “ a statem ent that the study involves research, an explanation o f the purposes o f the research and th e expected duration o f the subject’s participation, a description o f the procedtu es to b e follow ed, and id en tifica tion o f any p ro c e d u re s th a t are experimental. a description o f any reasonably foreseeable risks or discom forts to the subject. a description o f any benefits to the subject or to others that may reasonabfv be expected from the research. a disclosure o f appropriate alternative procedtu es or courses o f treatment, i f any, that m ight be advantageous to the subject. a statement describing the extent, if any, to w hich confidentiaiity o f record s identifying the subject will b e maintained. for research involving m ore than m inim al risk, explanations as to w h eth er any com pensation will be provided in case o f injury and w hether any m edical treatments are available i f injury occurs and, i f so, what they consist o f or w here further information may b e obtained. an explanation o f w hom to contact for answers to pertinent questions about the research and research subjects’ rights, and w hom to contact in th e event o f a research-related injury to th e subject. a statem ent that participation is voluntary, refusal to participate will involve no penalty or loss o f benefits to w h ich th e subject is otherw ise entided , and the subject may discontinue participation at any time w ithout penalty or loss o f benefits to which d ie subject is otherw ise e n tid e d .” earlier it was noted that general agreem ent exists as to d ie m oral im portance o f obtaining subject consent in western research. it was also however noted that critics feel that, as generally ap p lied , in form ed c onsent offers inadequate p rotection to research subjects. t h e latter scenario is plausible i f the obtaining o f inform ed consent is largely cerem onial. journal reviews indicate that in som e cases the p roced iu e is either not reported (a serious om ission in its own right) (see table i), or is not obtained. focusing 0 11 cases where it is obtained, we n eed to q uestion w h eth er or n ot th ere is a m eaningful exchange o f information. t h e p rocess should ideally b e participatory (i.e. a two-way process), and the inform ation p resen ted s h o u ld b e clea r and com p reh en sib le. clarity and com p reh en sion are particularly im portant in a multicultural society such as south africa, and researchers should consider the potential n eed to present inform ation in th e subjects’ preferred language * 20 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) having examined the con cep t o f inform ed consent, we can now explore the issue o f w hether or not the p rocess, as described , is applied in research in the field. a review of' the literature reveals that many studies either d o not take cognisance of, or m erely pay lip-service to the principles w hich form the construct o f a co d e o f ethics. pettit5 reports that in 1966 henry b eecher o f harvard m edical school published a survey o f ethical behaviour in clinical research in the new england journal o f medical r esearch. in an examination o f th e major journals, h e found 50 exam ples o f ethically dubious research on human subjects. consent was m entioned in only two o f these articles. table i indicates that in selected journal searches conducted by the author, inform ed consent was reported in relatively few pap ers.1 'for the purp oses o f the south a frican journal review it was deemed not necessary to obtain consent f o r p apers concerned with ca se histories, analyses o f injuries, technical or biochem ical information, surveys, review articles, m athem atical models, and research on nonhumans. i t was considered necessary fo r research utilising ‘c a p tiv e’ p opu lation s such as students, school children, tou rn a m en t p a r tic ip a n ts , em p loyees, patien ts, inm ates etc, where subtle form s o f coercion may op erate even i f that is not the intention. a ls o , in research concerning minors, it was deem ed necessary f o r written paren tal informed con sen t to be obtained. on th e p ositive sid e in th e south african reviews, som e authors ind ica ted that som e form o f consent was elicited , that subjects were volunteers, or that e thics c om m ittee approval had b een obtained. it m ust b e stressed th a t th e negative results d o not necessarily m ean that con sen t was n ot obtained, nor that subjects w ere abused or exp loited . t h e potential for abuse how ever exists, and ‘ ... w e m ust b e aware o f th e rights o f subjects and not take th e exp ed ien t route to con d u ct our research v 1'’05’ again w h ilst not indicating abuse, th e review s above introd uce the p ossibility that many resea rchers either d o not take cog n isan ce of, or m erely pay lip -serv ice to, th e p rincip les which form the construct o f a c o d e o f ethics. from th is the conclu sion cotdd b e drawn that in s u fficie n t a tten tion is b e in g p aid to th is controversial yet necessary facet o f research ethics. perhaps th e resea rch ers or their d efen d ers wotdd cou nter th a t con sen t was ob tain ed b u t was not reported in th e m anuscripts. t h is however will not do. non-reporting raises d ou b t about th e om ission o f a com m only a ccepted resea rch eth ics practice. captive populations t h e con cep t o f inform ed c onsent has im portant im plications for research hi sports m edicine, where subjects are often drawn from ‘captive’ populations, such as patients, students, tournament participants, team m em bers etc. such subjects m ay either perceive an elem ent o f coercion in participation, or an elem ent of sanction attached to non-participation. in cases such as this, th e issue b ecom es one o f how free subjects are, rather than ju st one o f how inform ed they are, and researchers need to question w hether or not utility' trum ps th e right to self-determ ination o f subjects. in th ese scenarios it is necessary to consider w hether the autonom ous ch oice o f subjects is valued intrinsically rather than extrinsically. in other w ords, is autonomy valued for its own sake or m erely used towards justification for research. p atrick'"','i;m states that ‘ ... critical to scientific su ccess is a ready supply o f experimental subjects ....’ . t h e crucial phrase h ere is ‘ready supply’ , and it is acknowledged that recruitm ent is easiest i f one has a large cap tive p op u la tion in an institution, or presum ably i f one has access to such a population, e.g. patients, participants in a tournament etc. c oercion and sanction are th e im portant elem ents to con sid er when recruiting volunteers from captive popidations. z elazn ik7 reports that regulations at p urdue u niversity p r e c lu d e in v estiga tors from recru itin g s u b je cts for resea rch from cla s s e s con d u cted by the investigator. t h e reason for th is is obvious: students could p erceive that volunteering may im prove tlieir grade, or conversely that not volunteering co id d b e to their disadvantage. thus e ith e r c o e r c io n or s a n ctio n or b o t h c o u ld b e p erceived . t h is requirem ent obviously lim its th e am ount o f research, and investigators w d l contend th a t it ham pers their p roductivity and retards the advancem ent ol k now ledge. t h ere may b e sym pathy for such claim s, b u t th e issue is n ot w h eth er research is con d u cted , b u t w h eth er subjects are coerced . t h ere is a further, m ore subtle form o f coercion th a t u ndoubtedly takes p la ce in resea rch settings. in sports m ed icm e for exam ple, an authority figure (e.g. coa ch , adm inistrator etc) cou ld tacitly approve a study by malting contact w ith th e subjects on b e h a lf of the researcher. r elatively uninform ed individuals are likely to ignore a violation o f th eir autonom y i f th e p ossibility ol sanction is p erceived . i f such an authority figure gives perm ission for p erson s to b e table i: reporting o f inform ed consent in selected journals. b rodie & stopani (1990) journal consent appropriate consent reported % reported sa medical journal (1994) 42 9 21.4 sa journal for sport, pe & ree (1982 -1992) 109 14 12.8 ergonomics sa (july 1989 july 1993) 20 1 5 sa journal of sports medicine (1990-) 13 9 69.2 british journal of sports medicine3 81 14 17.3 sports medicine september 1996 21 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) pevaryl the topical antifungal u tilis e d as re se a rch s u b je c ts , s h o u ld a r e s e a r c h e r p r o c e e d w ith data c o ll e c t io n ? i he a n sw er is no. in d iv id u a ls s h o u ld co n s e n t, and c o e r c io n or th rea t ol s a n ctio n sh o u ld not be e le m e n t s in the p ro c e s s . f urther, su ch a u th ority fig iu c s sh o u ld not be involved in the re se a rch p r o c e s s in any way, n or s h o u ld th ey have any a c c e s s to d a ta .' t h is is not to suggest that p ro g re ss in research sh o u ld be reta rd ed through petty regulations. r ather, re se a rch e rs sh o u ld be left w ith the th ou gh t that they ou ght to be aware of the potential for co n flic t betw een virtue and self-in terest, and that resea rch sh o u ld be g u id ed bv d c o n to lo g ic rath er than c o n s cq u cn tia lis t eth ica l p rin cip les. c o n clu sio n t h e p a p e r h a s r e p o r t e d g u id e lin e s as to w h en o b ta in in g co n s e n t is d e e m e d a p p ro p ria te , and h as p r e s e n te d e v id e n c e that in d ic a te s that r e s e a r c h e r s e it h e r d o not o b ta in co n se n t (o r at least d o n ’ t report it), or that th ey m e re ly pay lip -s e r v ic e to the c o n c e p t. w ith regard to "ca p tiv e’ su b je ct p o p u la tio n s , the a b s e n ce o f c o e r c io n and th reat of’ sa n ctio n in the c on sen t p r o c e s s lias b e e n e m p h a s iz e d . it h a s been n o te d that s p o r t s m e d ic in e r e lie s h e a v ily on r e s e a r c h , and that its s u b je ct ba se is often draw n fr o m " c a p t iv e ’ p o p u la t io n s s u c h a s p a t ie n t s , tou rn am en t p a rticip a n ts e tc. p ro g re ss h as d e m a n d e d th a t s u c h s u b je c t s be in c r e a s in g ly s u b je c t e d to invasive p r o c e d u r e s , and the h isto ry ol re se a rch in the tw en tieth cen tu ry p r o v id e s abu n d an t e v id e n c e s u p p o rtin g (lie co n te n tio n that in d iv id u a ls are op en to e x p lo ita tio n . w h ilst it is p r o b le m a tic , in fo rm e d c on se n t as a p rin cip le is in te n d e d to sa fegu a rd e x p e rim e n ta l s u b je c ts from a b u se s. a s s u c h , it s h o u ld serv e as a r e m in d e r to r e s e a r c h e r s th at they o u g h t to be aw are o f the p o te n tia l lo r c o n flic t betw een se lf-in te r e s t and virtue. refer en ce s 1. veatch iim (e d ) (1 9 8 9 ). m ediad ethics. jones & bartlett publishers. boston. 2. rifkin j. quoted in ethics in embryo: u symposium (1 9 8 8 ). ilarpcrs magazine 3 : 57-03. 3. brodie va and stopani k (1 9 9 0 ). experimental ethics in sports medicine research. sports medicine 9 ( 3 ) : 143-150. 4. i'ailcn rr & beauchamp tl (1 9 8 0 ). .1 history and theory of informed consent. oxford university press. 5. pettit p (1 9 9 3 ). instituting a research ethic: cliilliny & cautionary tales. bioethics 6 ( 1 ) . 89-112. 0. medicine & science in sports & exercise. (1 9 9 0 ). policy statem ent. vo! 2 2 ( 1 ) . i’i. 7. zelaznik hn (1 9 9 3 ). ethical issues in conducting & reporting research: a reaction to kroll. matt & safrit. quest 45. 02-68. 8. mahon j (1 9 8 7 ). ethics & drug testing in human beings, in moral philosophy & contem porary problems. 199-211 (e d ) e rans jdg . royal institute o f philosophy. 9. kroll u’ (1 9 9 3 ). ethical issues in human research. quest 45, 3 2 n . 10. patrick jm (1 9 8 3 ). volunteers or pressed men: human subjects in science. ergonomics 2 6 ( 7 ) : 637-038. 22 ztzh. the topical antifungal most prescribed by dermatologists' if you wish to see more, call your roche syntex division representative at (0 1! ) 974-5335 tinea capitis otitis externa tinea b a rb o e prophylactic treatment r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) sports-related head injuries: a neuropsychological perspective s i anderson mse (clin psych) (natal) n o t e : an earlier version o f this paper was presented at the 6th international sasma conferenee held in durban, march 22-24, 1995 s u m m a r y mild head injuries occur across a range o f different com petitive and recreational sports. concern has been expressed regarding the ou tcom e o f th ese injuries, and it is generally accep ted that what has until recently been regarded as relatively minor or trivial head injuries (c o n c u s s io n s ). can give rise to long-term and possibly even perm anent neurocognitive effects. this may occur in the absence o f direct impact or loss o f consciousness. moreover, the effects o f many minor blotvs or concussion s may be cumulative. however, despite an acknow ledgem ent o f p ossible residual neu­ rocognitive effects arising from concussion, these are often inadequately evaluated by medics and coaches, and the sym ptom s th ereo f may he minimized by a com ­ p etitive a th lete who is keen to be declared fit to return to the game. this paper reviews the nature o f sports related head injuries, p ossible neurocognitive sequ e­ lae. and discusses the evolving role o f the neuropsy­ chologist in the evaluation and m anagem ent of indi­ viduals with such injuries. r isk amd prevalence of sports-related head injury brain injiuies represent one o f t he most catastrophic athletic injuries1 and there appear to be few sports that do not carry som e risk o f a concussion or mild head injury. obviously the risk is greatest in contact sports such as boxing and wrestling, the martial arts, rugby and soccer. indeed, blows to the head may be exp ect­ ed or even intentional in some o f these sp oils.a high risk o f injury also exists in sports using equipment to propel people or objects at high speed; representative exam ples include motor sports, cycle-racing, ice-skat­ ing, cricket, sluing, horse-riding, hockey, and g o l f sports that involve height (e.g. diving, sky-diving, clim bing, and equestrian events) also present more o f a risk than sports that are played with both feet on the grou n d /1 som e recent literatim: has focused on the more recreational sports such as skateboarding and address for correspondence: sj anderson depart men t o f psych ology, university o f natal ( pmb) p. bag x01. scottsville, 3209 tel: (0 3 3 1 ) 260-5372 e-mail: a ndersons @ps y. unp.ac.za b lade-skating,j cycling,511 and je t-s k is .7 given that acceleration forces acting on the brain may be poten­ tially damaging.'-" sports such as bungee jiunping may not be entirely free o f risk."1 generally speaking, sports-related head injuries account for only a small percentage o f all head inju ries," although estim a tes range from 3-66% depending on study s ite .1’ 11 assessing the prevalence o f sports-related concussion or mild head injiu v is problem atic for the sim ple reason that m ost eases go lu u e p o ite d ,11 and it has even been suggested that many diagnosed eases o f facial lacerations and contu­ sions should be considered as undiagnosed eases o f c o n c u s s io n .1’ the in cid en ce of such craniofacial injuries in sports is high, with one recent study citing its occurrence in 8% o f consecutive adm issions to a london hospital (n =950)."’ statistics suggest that the sports carrying the greatest risk varies according to factors such as age, sex, and study site. for example, in the united states, it is american football (although gymnastics, ice-hockey and wrestling are also well rep­ resented); in england, soccer, rugby and horse-riding; and in scotland, g o l f " ''’ there is increasing concern that yoim gstcrs inidcr 16 years represent a high risk group for sustaining head injuries in a variety o f sport­ ing and recreational activities.1" as a result, this group has been targeted for prophylactic intervention.-" i iie nature of mild head injury problem s o f definition and evaluation any discussion o fh e a d trauma must con sider severity as a defining characteristic and predictor o f outcom e. head trauma exists on a continuum with mild bum ps causing uo overt sym ptom s representing one end o f the continumn, and veiy severe head injiu ies causing pro­ longed com a at the other. likewise, a variety o f descriptors are used to d escribe position on this con ­ tinuum. for exam ple, a head injury may be described as mild or very mild (often referred to as concussion or trivial head traiuna) through m oderate, severe, to very severe.-1-' traditional m easiues o f severity and out­ com e include the evaluation o f the presence and dura­ tion o f unconsciousness (com m only nieasined by the glasgow coma seale) as well as the period o f post traumatic amnesia (pta), although there is som e question o f their validity and reliability in assessing mild head traiuna.is the evaluation o f concussion is even more con tro­ versial, and there appears to be no universally accept­ ed definition o f concussion or o f its severity. the previ­ ously held assertion in the definition proposed bv the congress o f neurological surgeons (1966)' (' the defi­ nition proposed by the committee o f h ead injury nomenclature was ~a clinical syndrome characterized by immediate and transient post-traum atic impairment o f neural functions, such as alteration o f consciousness, disturbance o f vision, equilibrium, etc. due to brain stem sports medicine september 1996 23 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) involvement".) that the sym ptom s o f concussion are transient, has been questioned by research that has found m ore protracted p eriods o f recovery and persis­ tence o f cognitive effects,l'! ii and there have been calls for a revised definition to accom m odate this evi­ d ence.24 traditionally, the severity o f concussion had been d escribed in terms o f loss o f consciousness (loc) and extent ol pta, although it has been noted that other sym ptom s such as changes in orientation, lack o f co-ordination or balance, com plaints o f d ouble or blurred vision, and urinary incontinence may also b e d iagnostic.'4 t h e possibility o f delayed sym ptom atol­ ogy should b e con sidered in som e cases, and m ight include hypothalam ic disturbance (such as eating or sleeping disturbance), sensitivity to alcohol, and neu rocogn itiv c dysfu n ction .14 t h e co n ce p t o f delayed effects is supported by research indicating that slow ­ ing o f cerebral b lood flow, when present, b ecom es m ax­ imal only several days after a concussion.15 one o f the problem s facing sports m edicine practi­ tioners lies in the assessm ent o f concussion, and there are indications that accurate and reliable assessm ent o f severity is d ifficu lt to attain in practice (d r j g odlonton, personal com munication, d ecem ber 1994). r ecognition o f the need for a m ore accurate grading ol concussion has been add ressed in recent p ublica­ tion s,1 14 although the system offered by cantu appears to b e th e m ost useful in this regard. t h ree grades o f severity are described: (1) m ild characterized by no loc and pta < 30 min. (2) m oderate characterized by loc < 5 inin. and pta 30 min < 24 hours (3) severe characterized by loc > 5 min. and pta > 24 hours. t h e problem s o f accurate evaluation are com pounded by th e finding that g rade 1 or m ild concussions account for 90% o f all concussions,1 yet these are probably the m ost difficult to assess. it has been sug­ gested that m ild concussion may not b e recognized by th e person him sell and that it is often a team m ate or opponent who notices behavioural sym ptom s.1 other clinicians em p h asize th e im portance o f assessing p ossible confusion, and recom m end questions such as “ what is the s c o r e ? ” or “ what is the name ol the opposing team ” , or questions relating to the athlete’s background.25 t h e use o f sim ple neurological measures such as finger-to-nose, lieel-to-toe standing, and stand­ ing on one foot with the other suspended have also b een recom m ended, since they may b e failed in up to 50% o f concussed individuals.85 m echanism s o f injury it is w idely accepted that cerebral concussion can arise t o m b oth im pact and n on -im p act injuries. t h e neuropathology associated with im pact injuries is well d escribed in the literature, and may include both primary" and secondary' effects.20 by com parison, the n eu rop ath ological effects arising from non-im pact head injuries is less well understood. nevertheless, there is recognition that cerebral brain dam age may occur: (1) without im pact to the head, and solely through exposure to acceleration forces; and (2) in the absence o f pta or loc.!l in th e majority o f cases, the neuropathology in im pact and non-im pact injuries can b e attributed to the m ovem ent o f the brain inside the skull.21 in both rapid deceleration injuries (e.g. when a moving head is suddenly brought to rest) and sequential acceleration deceleration injuries (i.e. whiplash), shearing planes mav b e set up, giving rise to diffuse axonal injury (d a i). such injuries may b e easily sustained w hen an athlete com es adrift o f a horse or b icycle, or when a rugby or soccer player is tackled roughly from behind. t h e significance o f these types o f forces in causing con ­ cussion is em phasized in research that indicates that while the brain is tolerant o f the com pressive and ten­ sile forces giving rise to coup and contra coup injuries, it is relatively intolerant o f acceleration-induced shear­ ing forces.1 it has even b een suggested that concussion b e redefined as an a cceleration/deceleration injury to th e head.27 however, a major source o f difficulty for the clinician attempting to evaluate concussion is the lack o f correlation betw een th e m agnitude o f the b io m e ­ chanical forces, th e nature and severity o f neuropath o logical dam age, and the behavioural m anifestations.14 t he postconcussive syndrom e a num ber o f sym ptom s have been observed to occur subsequent to concussion or m ild head trauma and are collectively referred to as postconcussive syndrome (pcs). t h e range o f possibfe sym ptom s that may b e experienced is sum m arized in table 1, although it is noted that con siderab le inter-individual variability exists.8'111 12 15 22 28 29 w hile sym ptom s such as vomiting, nausea, drow siness, and blurred vision may disappear within a few days o f the injury, other pcs sym ptom s (particularly the neurocognitive ones), may persist for weeks, months, or even years in a small num ber o f individuals.12 table 1: range o f sym ptom s associated with p ostcon ­ cussive syndrom e (pcs) somatic: headache, dizziness, vertigo, insomnia, vomiting, fatigue and weakness, loss of appetite, drowsiness, blurred vision, strabismus, menstrual irregularities, sleep irregularities, decreased noise tolerance, sensitivity to medications and alcohol, restlessness, clumsiness, and postural changes (associated with disturbed sensorimotor syndrome) neurocognitive: impaired attention and eoneentration, memory and learning disorders, reduced mental flexibility, slowed reaction time, impaired decision making, cognitive impiilsivity, speech difficulties, mental latigne. neuropsychiatric: depression, anxiety, emotional lability, irritability, lowered frustration tolerance, somatization and liypochondriaisis, denial o f symptoms, apathy or lack ol spontaneity, personality change. although the notion o f perm anency o f som e ol these effects has been m entioned in recent studies,2'-29 this concept rem ains controversial. a recent study on south african university-level rugby players investigated pre and post-season neuropsychological functioning in con ­ cussed and non-concussed players and found p ersist­ 24 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) ing deficits at the 3 month follow-up in th e form er.“ 'in another study com paring college soccer players with tennis players on a battery o f neuropsychological tests, there were no significant group differences on these measures although the soccer players dem onstrated a significant negative correlation betw een num ber o f gam es played and perform ance on the paced a uditory serial a ddition test.30 w hile causality was not estab­ lish ed in this study, it has b een pointed out that a s o c­ cer player could head the ball som e 2 ,00 0 tim es d ur­ ing a soccer career, and that this practice may not be free o f r i s k / 1 w hile it has been found that m ost co n ­ cussed adults regain prem orbid functioning within one to three m onths post-injury,15 th is pertains to young adults without a history o f previous head injury. the negative outcom e o f cumulative effects o f numerous m inor brain assaults has been dem onstrated in studies on boxers and other athletes exposed to repeated con ­ cussions.23 a cknow ledgem ent o f th e persisting effects following concussion and th e im portance o f neuropsychological testing, is apparent in the recently published dsm-iv, 28 w h ich now includes these as part o f th e research cri­ teria for postconcussional disord er (see table 2). table 2: extracts from dsm -iv criteria for p ostcon ­ cussional d isorder a. a history o( head traiuna causing significant cerebral concussion (likely manifestations of concus­ sion include loss o( consciousness, post-traumatic amnesia, and less commonly, posttraumatic onset of seizures. the specific method of defining this criterion needs to be established by further research). b. evidence from neuropsychological testing or quantified cognitive assessment of difficulty in attention (concentrating, shifting focus of attention, performing simultaneous cognitive tasks) or memory (learning or recalling information). c. three or more ol the following symptoms which occur shortly alter to the trauma and last at least 3 months: fatiguability; sleep disturbance; headache; vertigo or dizziness; irritability or aggression on little or no provocation; anxiety, depression, or affective lability, personality change, apathy or lack of spontaneity. t h e pathophysiology associated wit h pcs is thought to reflect possible damage or dysfunction at the level o f the basal frontal and upper brain stem structures the sites o f lim b ic and hypothalam ic connections." t hese areas are particularly prone to rapid a ccelera tion / d ecelera tion -in d u ced traum atic brain injury,™ and there is som e suggestion that th e sam e regions may be affected in w hiplash injuries.9 the detection o f such pathophysiology is problem atic and has contributed to th e widely h eld view that in the absence o f loc or dem onstrable neurological indicators, th e sym ptom s o f pcs are functionally-related. however recent research indicates that such a view is no longer tenable. for exam ple, one group o f researchers studied 21 patients with whiplash injuries using a range o f investigations (neurological, x-ray, eeg, baep mri, ontoneurological and neuropsycho­ logical ).h cognitive dysfunction was dem onstrable in 20 patients at a 3-month follow-up, and 4 o f these contin­ u ed to experience cognitive dysfunction at a 12-month follow-up. o f significance in this and other studies o f pcs, is th e relative insensitivity o f conventional ra d io­ logical and el ectrophysiological investigations in co m ­ parison with neuropsychological testing.” 22'32 t h e manifestation o f pcs-related neurocognitive deficits is variable, although on th e basis o f mild head injury research, d eficits in the areas o f attentional focusing/arousal, red uced speed and quality o f infor­ mation processing, difficulties in mental tracking, and impaired m em ory acquisition can b e expected.21 at a behavioural level, one m ight see a range o f symptoms including: behavioural inconsistency (at tunes the p er­ son perform s well yet at others he may make inexplic­ able m istakes); difficulty in filtering out irrelevant or background information or failure to attend to the m ost important or crucial aspects o f a situation; loss o f focus in conversations; difficulty in calculating and thinking through a plan or solution; difficulty in sus­ taining intense mental activity for an extended p eriod o f tim e (i.e. fatiguability); difficulty in shifting o n e ’s focus o f attention back and forth among various tasks, or to m onitor various tasks simultaneously; unreliable m em ory.21,20'33 t h e information processing and m em ory deficits m entioned above could increase vulnerability to fur­ ther injury. in this regard, it has been noted that split second decision malting is required in many sports and that a com prom ise in this ability could result in an ath­ lete habitually being in the “ wrong place at the wrong tim e ” .11 s om etim es, neu rocogn itive d e ficits may only b ecom e apparent in th e context o f mental or physical stress. for exam ple, a frequently cited study by gronwall & w rightson34 on mild head injury found that com parative neuropsychological deficits (m em ory and mental vigilance) only b ecam e apparent w hen the sub­ je c ts were p laced under the stress o f artificial altitude (3,8 00 feet in a hyperbaric environment). in another s ' udv, the failure o f neuropsychological tests to d etect im pairm ent in som e individuals was attributed to the relatively undem anding and short duration o f an assessm ent; som e individuals may b e able to recruit enough resources to com plete the tests successfully, only to exp erien ce su b seq u en t exhau stion and fatigue.15 role of the neuropsychologist in the assessment of sports-related head injuries given the established persistence o f neurocognitive effects in pcs as well as th e need for neuropsycholog­ ical evidence in th e dsm -iv criteria, th e rationale for the involvement o f a neuropsychologist in the assess­ m ent o f sports-related h ead injuries is already sub­ stantiated. t h e relative sensitivity and precision o f neuropsychological m easurem ents make them well suited for assessing the neurocognitive deficits that may accom pany mild head traiuna.11 in th e assessm ent o f pcs, neuropsychological testing is not only cost effective, but also the only feasible way o f providing objective evaluation o f possible subtle cognitive dys­ function. som e em phasis should b e placed on the fact that sequelae are likely to be very subtle, i f detectable at all, and this requires carefi.il selection o f test p roce­ dures (recom m en ded tests and their areas o f assess­ sports medicine september 1996 25 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) m ent are sum m arized in table 3). to som e extent, th ese tests may b e con sidered m ea­ sures o f overall cerebral efficiency, and are th ereloie likely to b e accurate ind ices o f th e neurocognitive d if­ ficulties that characterize pcs. a ssessm ent o f som atic sym ptom s may b e m ade using th e scl-90-r, a rating scale sensitive to anxiety, depression, and cognitive failu res com m on ly a ssocia ted w ith m ild head injuries.'1 apart: from giving som e objective validation to an ath­ le te ’s subjective com plaints following concussion, the m ain use o f a neuropsychological assessm ent w ill b e to provid e th e trainer, coach, or sports m edicine practi­ tioner with relevant inform ation about th e nature and severity o f possible neurocognitive deficits. in a d d i­ tion, repeated or serial assessm ents m ay docum ent the rate and extent o f recovery. notwithstanding the advantages o f neuropsycholog­ ical assessm ent, there are a num ber oi pitfalls w hich may b e encom itered by th e neuropsychologist. t hese include: use o f instruments which lack requisite sensi­ tivity or are inappropriate to the nature o f the assess­ ment; failure to consider dem ographic variables in the interpretation o f test scores (education, occupation, age, sex and socio-econ om ic status are all important determ inants o f n eu rop sych ological perform ance). t h is may lead to over/under-interpretation o f test scores (e.g. patients with superior prem orbid abilities are often able to com pensate for m ild neurocognitive deficits through increased effort).’’-1" w hile th ese are unlikely to p ose m uch o f a difficulty for the experi­ enced neuropsychologist, th e risk o f m isinterpretation is increased in assessm ents con d u cted by inexperi­ en ce d clin icia n s.2 (~ the south a frica n clinical neuropsychology a ssociation (sacna.) was set up in 1984 to represent the profession o f neuropsychology in this country, and at present there are 34 accredited full members. d etails of members practising in the various provinces may be obtained from the sac n a membership secretary, prof. d. griesel, institute fo r behavioural sciences, tjnisa, tel: 012-429 6 0 6 3 ). a further role o f th e neuropsychologist lies in d eter­ mining th e safe return to training or com petitive sport. t h e im portance o f such d ecisions cannot b e underesti­ mated, since there is evidence that a concussed athlete is at risk for further concussions.1 moreover, there is th e risk o f a second im pact syndrom e with potentially fatal con seq uen ces.14 t h ere are no clear guidelines on when it may b e safe to return an athlete to the game following a concussion. cantu recom m ends resumpt ion o f sport i f asym ptom atic for 1 w eek (i.e. absence o f pcs sym ptom s during rest or exertion ).1 t his period is lengthened in the face o f severe or previous concussion. other m ore conservative opinions are that a concussed player sh ould not b e allowed to play for at least 3 to 4 weeks after th e injury, especially i f the sport requires split-second timing or decision making.~'v,n current neuropsychological opinion is that athletes should abstain from com petitive sport until all neurocognitive svm ptom s have disappeared; this view is com patible with the recognition that the persistence o f neuropsy­ chiatric sym ptom s a n d /o r positive results on relevant diagnostic tests sue contra-indications for resumption o f com petitive sport.114 ultimately, th e return to sport is a decision based on clinical ju d gem en t although it seem s important to establish that the athlete p oses no risk o f injury to h im self or oth ers.14 it is clear that a neuropsychological assessm ent may allow for m ore confident decision-m aking on the part ol th e sports m edicine practitioner. a final role for th e neurop sychologist lies in ed u ca ­ tion, n ot only o f athletes at risk, b u t also o f coa ch es, trainers, and sports m ed icin e practitioners w h o may b e unaware o f th e nature o f sports-related head injuries. k now ledge about th e nature o f assessm ents p erform ed by n europ sychologists is lacking in a large proportion o f south african trained m ed ica l practi­ tioners, and m arketing o f th e neuropsychological pro­ fession in south a frica appears to have lagged behind our overseas counterparts. t h is is probably d ue to the small num ber o f a ccred ited n europsychologists, an even sm aller num ber o f educators, and relative pauci­ ty o f local research. in line with overseas trends, som e effort should b e m a de in preventative p ro­ gram m es that create p u b lic awareness about safety in sport. g overnm ent legislation (with accom panying su bsid isation ) for th e com pulsory use of h elm ets by ch ild ren and adolescen ts is appropriate, as is the tar­ geting o f injury prevention through sch ool-b a sed ed u ­ cational p rogram s.'11 ultimately, th e num ber o f sports related head injuries can only b e red u ced through effective preventative m easures. h ere, recom m en d a ­ tions have inclu d ed: th e use o f h elm ets in recreation ­ al sports; th e n eed to d iscard w orn-out or dam aged equipm ent; p e rio d ic reviews o f rules and coaching techniques; the n eed for com p eten t instruction and close supervision o f ch ild ren , a d olescen ts and b eg in ­ ners in any sport; and adequ ate con d ition ing (fatigue and less than optim al fitness have b een m entioned as contributory factors to con cu ssion in som e studies, w h ile con d ition ing o f th e n eck m u scles has b een m en ­ tio n e d as a p reven ta tive m ea su re for w h ip la sh inju ries).1-1,181 t a b le 3: s u g g e s te d n e u r o p sy c h o lo g ic a l b a tte r y for ev alu ation o f pcs sensory/motor: quick neurological screening test revised (qivst) attention: digits forwards and backwards reaction time or letter/number cancellation lest* information processing and cognitive flexibility: symbol digit modalities test (sdmt) trail making test stroop colour word test paced auditory serial addition test (pasat) memory/new learning: rev auditory verbal learning test (ravlt) rey visual design learning test (rvdlt)* executive functioning: austin maze short category test* wisconsin card sorting test* neuropsychiatric: symptom checklist 90 (scl-90-r) * optional inclusions 26 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a final point likely to b e endorsed by all sports psy­ chologists is a com m ent by tem pler & drew who rec­ om m end th e n eed for a “ constructive philosophy that m akes sport enrich and refresh rather than dom inate and debilitate” (p.3 9 ).31 to this extent, the desirability o f com pulsory participation in contact sports at sch ool level has been questioned b o th overseas and in this cou n try .''" references 1. cantu r c : cerebral concussion in sport. sports med 1992; 1 4 ( l ) :6 4 7 4 . 2. zemper e d , pieter w: injury rates during the 1988 us olympic team trials for taekwondu. br j sp med 19 8 9 :2 3 ( 3 ) .1 61-16 4. 3. drew kt1, templer d i: contact sports. in: templer di, hartlage lc, cannon wg, eds. preventable brain damage brain vulnerability and brain health, new york: springer publishing company, 1 9 92 ; 15-29. 4. schieber r a , branch-dorsey cm, ryan gw: comparison o f in-line skating injuries with rollerskating and skate­ boarding injuries. j a m a 1994:271 (2 3 ) -.1856-1859. 5. olkkonen s, laiidenranta u, slatis p, honkanen r: bicycle accidents often cause disability an analysis o f medical and social consequences o f nonfatal bicycle acci­ dents. scand j soc med 1993;21 (2 ):9 8 -1 0 6 . 6. gerberich sg, parker d, dudzik m : bicycle-motor vehicle collisions epidemiology o f related injury incidence and consequences. minn med 1 9 9 4 ;7 7 (4 ):2 7 -3 1 . 7. hamman bl, miller fb, fallal me, richardson j d : injuries resulting from motorized personal watercraft. j pediatr surg 1 9 9 3 ;2 8 (7 ):9 2 0 -9 2 2 , 8. ettlin tm, kischka u, reichmann s, radii ew, h eim s. wengen d et ah cerebral sym ptom s after whiplash injury o f the neck a prospective clinical and neuropsychological study o f whiplash injury. j. neurol psi/chiatry 1992;55 94 3-94 8. 9. sweeney je: nonimpact brain injury grounds for clinical study o f the neuropsychological effects o f acceleration forces. clin neuropsychologist 1 9 9 2 ;6 (4 ):4 4 3 -4 5 7 . 10. mees k : horstorungen nach bungee-springen (hearing disorders after bungee jum p ing?) larijncjorhinootologie 1994; 7 3 ( 3 ) :1 4 6 -1 48. 11. ingersoll cd: long term effects o f closed head injuries in sport. sports med 1 9 9 3 ;1 6 (5 ) 34 2-35 4. 12. m oes e : neuropsychiatric aspects o f head injury. in: ellison jm, weinstein cs, hodel-malinofslcy t, eds. the psychotherapists guide to neuropsychiatry diagnostic and treatment issues. washington, d c : am erican psychiatric press, 1 9 94 ;21 7-254 . 13. levin hs, benton a l , grossman r g ; neurobehavioural consequences o f closed head injury. new york: oxford university press, 1982. 14. henderson jm, browning d g : head trauma in young ath­ letes. med clinics north america 1 9 9 4 ;7 8 ( 2 ) -.289-303. 15. binder lm, rattok j: a ssessm ent o f the postconcussive syndrome after mild head trauma. in: lezak md, ed. a ssessm ent of the behavioural consequences o f head trau­ ma. new york: a lan liss, inc. 1989;37-48. 16. hussain k , wijetunge db, jackson it: a comprehensive analysis o f craniofacial trauma. j trauma 1 9 9 4 ;3 6 (1 ) :3 4 -4 7 . 17. lindsay kw , mclatchie gr, jennet b : serious head injury in sport. bm j 1 9 8 0 ;2 8 1 :7 8 9 -7 9 1 . 18. trettin ii: schadel-hirn-traumen durch sport ( cranuxxrcbral trauma caused by sp orts). j lymphol 1 9 9 3 ;1 7 (2 ):3 6 -4 0 . 19. schmidt b. llollwarth m e : sportunfalle im kindes-und jugendaltei (sports accidents in children and adoles­ cents). j kinderchir 19 8 9 ;4 4 :3 5 7 -3 6 2 . 20. wilson pd, testani-dufour l: bicycle safety proqrams targeting injury prevention through education. pediatr nurs 1 9 9 3 ;1 9 ( 4 ) -.343-346. 21. lezak m d : neuropsychological assessment. 3rd edition. new york: oxford university press, 1995. 22. boll tj, barth j: mild head injury. psychiatr developm 1983 ;3:2 63 -2 75. s3. templer di, hartlage lc, cannon wg, eds. preventable brain damage brain vulnerability and brain health. new york: springer publishing company, 1992;lv-xv. 24. maddocks dl, saling m m : neuropsychological sequelae following concussion in australian rules footballers. [paper presented at the ins-australian society for the study of brain impairment pacific rim conference. gold coast, queensland, australia: july 13-16 1 9 9 1 ]. 25. mclatchie g, jennet b: head injury in sport. b m j 1994 3 0 8 :1 6 2 0 -1 6 2 4 . 26. k a y t, lezak m d : the nature o f head injury, in: corthell d , ed. traumatic brain injury and vocational rehabilita­ tion. menomonie, wisconsin: stout vocational rehabilitation institute, 1990:22-65. 27. rutherford wii: postconcussion sym ptom s relationship to acute neurological indices, individual differences, and circumstances of injury. in: levin hs, eisenberg hm , benton a l , eds. mild head injury. new york: oxford university press, 1 9 8 9 ;2 1 7-228. 28. american psychiatric association: diagnostic and statis­ tical manual o f mental disorders. 4th edition. washington, d c : american psychiatric association, 1994;70 4-706 . 29. shuttleworth-vlordan a b , puchert j, balarin e: negative consequences of mild head injury in rugby a matter wor­ thy of concern. [ paper presented at the 5th national neuropsychology conferences (s a c n a ). durban: julu 14-16, 19 9 3 }. 30. abreau f: psychological assessment o f attention and con­ centration in soccer players. [ dissertation] . california school o f professional psychology. fresno, california: (cited templer di, drew r h : contact sports. in: templer d i, hartlage lc, cannon wg, eds. preventable brain damage brain vulnerability and brain health. new york: springer publishing company, 19 92;30-40. 31. templer d i, drew r h : contact sports. in: templer d i. hartlage lc, cannon wg. eds. preventable brain damage brain vulnerability and brain health. new yirk: springer publishing company. 1992:30-40. 32. casson ir, siegel o, sham r, campbell e a , tarlau m, didomenico a : brain damage in modern boxers. j a m a 1984:251 (2 0 ) :2 6 6 3 -2 6 6 7 . 33. hartlage lc, rattan g: brain injury from motor vehicle accidents. in: templer di, hartlage lc, cannon wg, eds. preventable brain damage brain vulnerability and brain health. new york: springer publishing companu 1992 3-14. 34. gronwall d, wrightson p: cumulative effects o f concus­ sion. lancet 1 9 75 ;2:9 95 -9 97. 35 . gronwall d , wrightson p, waddell p: head injury the facts. a guide for families and care-givers. oxford: oxford university press, 1990. □ sports medicine september 1996 27 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) product news electrifying breakthrough in pain relief each year, south africans spend more money on analgesics than on any other pharmaceutical drug, including cardiovascular and antibiotic treatments. w hat is perhaps not fully realised, however, is the associated and cumulative toll this takes in terms o f side effect related problems, not least o f which is the large scale im pact on productivity. a new, highly effective and safe treatment for pain has been developed using a scientific breakthrough in bio-analgesic m embrane therapy. awarded a gold medal at the 35th eureka world trade fair for invention, acustat rx therapeutic membrane provides micro-current (1 0 -3 0 m icro-am p) stim ulation to soothe traumatised muscles and joints and injuries associated with sprains, strains, inflammation and swelling, arthritis, bursitis, soft tissue injuries, neck and lower back problems. micro-current therapy works at a sub-sensor level to trigger the body’s own bio-chemical and electro-physiological healing processes so that intra-cellular fluid levels are restored, electrolyte levels replenished, nutrients taken in and healing commenced. pain is effectively reduced through the introduction of a negative charge to the injured area. t h is stim ulates protein synthesis, production o f important amino acids and adenosine triphosphate (atp) and increases the transfer o f calcium into the cells, thereby electro-balancing these injured cells and aiding tissue repair. acustat rx is a high-tech synthetic polymer membrane which retains electric activity. its micro-amp charge is released when brought into contact with the skin and works effectively over a period of at least 4 8 hours. this is far greater than any traditional single otc analgesic dosage, with additional curative properties and no known side effects. the acustat rx electro-m em brane also effectively stim ulates reduction o f muscular inflammation and oedem a, thereby further reducing patient distress and discomfort. the patch is attached by means o f a self adhesive strip, available from your chemist, or, on joint areas, by means o f a gauze or crepe bandage. health care professionals worldwide have accepted this advances electro-analgesic product with great enthusiasm. its unique pain control, soft tissue healing and anti­ inflammatory properties are proving to be a successful combination in more cost effective patient treatment. the product’s obvious safety features, ease of application, and therapeutic action are all of additional benefit to the patient. acustat rx’s drug-free efficacy allows the patient to largely continue his or her work or sports activities with minimal impairment. f or fu r th er inform ation, p le a s e c o n ta c t susan drinkwater a t ( 0 2 1 ) 6 85 -7862 or 082-499-6229. eh 28 sports medicine september 1996 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) guest editorial edition oi the south african journal o f sports medicine which is devoted to drugs in sport i have been involved in drug testing for 9 years and have been campaigning for at least 6 of those for the establishment of a government funded cen­ tral drug control agency. it is therefore a great pleasure to confirm that such an agency is now £ p ace. similarly,it is a pleasure to note that dr pieter van der merwe’s analytical laboratory in the pham m colo^ department of the university of the orange free state has o ffic ia l been accredited by the international olympic ^ xt is the & s t * africa and the ses ond m the southern hemisphere. r e s^ j r fd d™ ^ t e v ^ tistical arialysis of the results oi drug testing for banned substances over a 9 year period makes fascinating reading x ms ef "f* tef *is " < * « s d e s iv w h lf ' as 9 c eterrenl table i shows this clearly when one notices that the average oerfo r ^ ffk s u t v e it w&s hetwecn 5 and 6%tirst b years. then over the na«=;t s £ n t £ £ , f “ “ s tests> t a g conducted t h l per.’ s v e ^ tte t n ';? to only 1,1% of posuves. the most unportant aspect of the control wi( hn ' f 111 spor' is an education programme with e recent establishment of sie g s t s t o g l t h ^ ^ ’ e f f ^ t ^ f jon become a reality, outof,™ , . ! fectlve education campaign and w a p 3 s on a regular basis’ 'vil1 sport ct ° n contoll“ g ^ e abuse of qultc familiar the t risks and dangers to athletes taking anabolic-androgen steroids (a.a.s) so it is re­ freshing to read d r lambert’s scientific analysis o f the proposed mechanisms of action of aas on s n o rr r b!em of harmlul and ergolytic drugs in sport is comprehensively covered bv n r o-nstmttaou he gives . j l r o t s l x t f the potentially harmful side effects of ordinarv and acceptable drugs. so, for the elite snorter,e7 tion’ n o ^ o ^ i f b ^ s t s s f ^ gssp"r ‘sns.-t's'te in selected events. there “ especially legal and ethical issues but also several practical ones. once these havp f e ^ l s h ™ " e “ 5 1utel5' *° blood tesunl(.sampling) bemg used more widely especialw in competition. so far, there have l t s e n z . p o f n » r t^ r “g<-tests' 11,6 editortol b « m l o f t h s w . d t f l the and p iy e re a drug and scandal .free to u rn a m e n t! dr joe skowno sports medicine june 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) e /asiopiasi; 0 n g o i n g s u p p o r t . for f u r t h e r i n f o r m a t i o n c o n t a c t t r o y b i n g h a m o n smithonephew leadership in worldwide h ealth canj ( 0 3 1 ) 7 0 1 5 2 4 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) r m ; s o i h i a f k i c a x .101 u x a l o r sports medicine volume 2 number 2 june 1995 guest editor dr j skowno editorial board dr m p schwellnus university of' cape town dr m e moolla private practitioner durban d r p de jager private practitioner pretoria dr j slcowno private practitioner johannesburg dr p schwartz private practitioner port elizabeth p r o fr stretch university of port elizabeth d r c de ridder private practitioner bloemfontein international advisory board lyle j micheli associate clinical professor of orthopaedic surgery boston, usa chester r k yle research director, sports equipment research associates california, usa p ro f h c wildor hollmann president des deutschen spo rtarztebund c s koln, west gennany howard j green professor, department of kinesiology ontario, canada george a brooks professor, department of physical education california, usa neil f gordon director, exercise physiology texas, usa edmund r burke associate professor, biology department, university of colorado colorado, usa graham n smith physiologist glasgow, scotland c o n t e n t s editorial j skowno blood doping and blood testing j skowno anabolic-androgenic steroids: 'f ~ effects on muscle size and strength mi lambert, a st clair gibson ergolytic and harmful drugs in sport d constantinou verbode middels in sport: resultate van toetsing vir die tydperk 1986-1994 pj van der merwe relationship between psychological factors and injuries in a non-contact sport, m marthinus, jr potgieter inspired air humidity effect on respiratory function in normal ad tilts during exercise cg hartford, c maldonado, gg rogers highest accolade for new sasma president 6 10 15 19 24 28 the editor the south african journal of sports medicine po box 38567. pinelands 7430 production andrew thomas publishing glenbarr publishers ce private bag x14 parldands 2196 tel: (o il) 442-9759 fax: (0 11 )8 8 0 -7 8 9 8 advertising marika tie waal/ajidrew thomas reproduction output reproduction printing hortors cover sponsored by ciba-geigy the views expressed in individual articles are the personal views o f the authors and are not necessarily shared by the editors, the advertisers or the publishers. no articles may be reproduced without the written consent o f the publishers. sports medicine june 1995 3 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) introduction there is an ever increasing interest in the sport community about the use of blood sampling and testing for doping control purposes. in conjunc­ tion with the 1994 commonwealth games in vic­ toria, canada, the canadian centre for drug free sport held a workshop to discuss blood sampling for doping control and the issues it raises for drug free sport. as one of the south african team doctors i was invited to the workshop and much of the information in this article was obtained from this workshop. definition the international olympic committee banned list defines blood doping as "... the administra­ tion o f blood or related red blood products to an athlete other than for legitimate medical treatblood doping is based on the principle that the amount of oxygen available to body tissues is lim ited by the number of red cells in the blood. in theory, increasing the red blood cells increases the amount of oxygen to the tissues which in turn allows the athlete to exercise more vigorously or for longer. an explanation of how this could be achieved is that an athlete could have blood removed, the red cells (erythrocytes) separated from the plas­ ma, and the red blood cells freeze preserved. meanwhile the athlete’s own red blood cells would gradually return to normal in about two months. shortly before a competition, the red blood cells could be thawed, reconstituted with normal fluid, and then reintroduced into the ath­ lete’s blood stream. consequently, the athlete would have the benefit of an abnormal number oi red blood cells, a condition known as erythro cythemia. the preservation of blood requires a sophisticated process and considerable laborato­ ry assistance. however, there is an easier method, that of transfusing someone else’s blood into the athlete (non-autologous or homologous blood doping). benefits o f blood doping blood doping would be of benefit to athletes in events taking place over a long time. for example, long distance running, cross country skiing and cycling. address for correspondence dr joe skowno, po box 67196, bryanston, 2021. tel: (o il) 706-1231. fax: (o il) 706-1235 risks of blood doping • infections, including hiv infection. • potentially lethal reactions from incompatible blood. • allergies • h ig h blood pressure blood sam pling the use of blood sampling (as opposed to urine testing) has advantages and disadvantages. advantages o f using blood samples • relatively fast procedure to collect sample • allows more reliable quantitative analysis for some substances • identity of samples indisputable • required to detect homologous (non-autolo­ gous) blood doping • provides best matrix to detect autologous blood doping • probenecid (masking agent) is now easily detected • corticosteroids are more easily detected • blood may be useful to confirm testosterone doping although urine may give much greater concentrations • plasma usually has greater concentration oi peptide hormones • there are population-based reference ranges for clinical haematological tests disadvantages for using blood samples • legal/ethical issues • sampling by medically trained person; small sample size (20m l); preparation of sample • reference ranges for peptide hormones and their secondary factors are unknown • analysis methodology is not fully established to do a complete profile, therefore urine analy­ sis is still required • urine is a better matrix for measuring beta-4 agonist (eg clenbuterol) • because of quick half-life of peptide hormones (6-24 hours) and steroids (72 hours) in blood, they may be hard to detect • haematological parameters may be altered by altitude and hard training • concentration of substances with low molecu­ lar weights are lower than in urine by a factor of 100-1000 although progress is being made on the detec­ tion of blood doping, there is at present no fool­ p r o o f method to determine that a high red blood cell count is the result of blood doping. dr norman gledhill, an exercise physiologist and former president of the sports medicine council of canada, met with ioc medical com­ sports medicine june 1995re pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mission representative dr arnold beckett in july 1978 and presented him with the evidence that blood doping definitely enhances performance. dr gledhill suggested that blood doping be banned specifically. he was of the view that blood doping need not be detectable to be on the banned list. athletes would know that blood dop­ ing was considered cheating and they would have to make the personal decision whether to cheat or not. dr beckett however, took the position that blood doping should not be banned until it could be detected. after the los angeles olympic in 1984, members of the us cycling team admitted having competed with the aid of blood doping. they had used blood from donors, not their own blood. o f seven athletes involved, three had become ill. shortly thereafter, blood doping was banned by the ioc. blood sampling not blood testing from a legal point of view, the analysis or actual testing itself is only one and perhaps the least problematic step in the use of blood samples for doping control. a preferable term is blood sam­ pling because it is this “front end” of the process that is legally the most sensitive. blood sampling in doping control: some practical considerations. sampling procedure: 1. blood sampling can be quicker than urine sampling. there is no need to wait for dehy­ drated athletes to produce a sample. 2. while physically invasive, blood sampling is far less a disruption to personal dignity. fe­ male athletes in particular, may be more com­ fortable giving a blood sample than being scrutinised while giving a urine sample. analytical: non-autologous (homologous) blood can be test­ ed. autologous blood at present cannot be detected. possibilities for the detection o f autologous blood transfusions. 1. repeated testing of erythropoeitin ratio to haemoglobin and haematocrit to establish normal values? 2. parameters to detect haemolysis after the transfusion of stored blood? 3markers for senescent erythrocytes? legal and ethical aspects these aspects are potentially very complicated betwese ° f tllc overlap 811(1 possible conflict inte rnationa 1 laws such as the european charter of human rights. national laws such as domestic constitutional documents guaranteeing certain individual rights or protections. 3. state or provincial laws in nations with feder­ al systems of government. 4. the rules of international sport governing bodies and the rules of their national affili­ ates. 5. the requirements o f international games organisers, the international olympic committee and the commonwealth games federation being obvious examples. one area where conflict already manifests itself is dispute resolution, particularly the role, if any, o f domestic courts in intervening in otherwise private sporting matters. particular issues 1. consent: without informed consent the taking of a blood sample, being physically invasive, is considered legally to be an act of assault and battery with criminal and/or civil liability. this requires an additional and specific consent form, above and beyond consent to participate in doping control which is a condition of membership for all national sporting bodies and teams. 2. use o f blood sample: it must be clearly stated on the consent form that the blood samples will be used for the testing for banned substances only. under no circumstances may the sample be used for research or any other purposes unless clearly stated and endorsed and understood by the athlete concerned. conclusions in view of the continuing problems associated with the relatively simple process of requiring, collecting, identifying and securing urine sam­ ples, the practical difficulties of a successful blood sampling programme should not be under­ estimated. i f urine sampling can still problemat­ ic, due to human failure if nothing else, blood sampling will give rise to no fewer errors. at the winter olympic in lillehamer, norway in 1994, limited blood sampling was done for the first time. this was discussed at the workshop held in victoria, and as a result two countries, canada and norway made the decision to use blood sampling as part of their doping control measures. other countries will be monitoring their progress with interest and once many of the more serious problems have been ironed out it is likely that blood sampling will become an addi tional tool in doping control internationally. references 1. d u b in charles l . (c o m m is sio n er ), c om m ission o f inquiry into the u se o f d ru gs and b a n n ed practices in ten d ed to in crease a th le tic perform ance. o tta w a canada 1 9 9 0 . p a y n e, sim on d .w . m edicine, sport and the l aw . b lackw ell scientific publications l on don . 1 1 9 0 . 3. yesalis, c harles, e. a n a b o lic s ter o id s in s p o rt and l xercise. h u m a n k in etic publishers. 1 9 9 3 . q sports medicine june 1995 5re pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) anabolic-androgenic steroids: effects on muscle size and strength mi lambert phd, uct medical school a st clair gibson mbchb, uct medical school introduction androgens are a class of steroid hormones which are secreted mainly by the testes, but also by the adrenal gland and ovaries. testosterone is the main androgen secreted by the testes. testoste­ rone regulates differentiation and secretory func­ tion of the male sex organs and stimulates pro­ tein synthesis in muscle, bone and kidneys. testosterone was isolated in 1935 and by 1937 pharmaceutical companies were already perform­ ing clinical trials with testosterone to determine it’s potential muscle building properties and uses in medicine.2 however, treatment with testos­ terone was not successful, because it was difficult to sustain high circulating plasma levels of testosterone after testosterone treatment. orally ingested testosterone is rapidly absorbed into the portal blood and degraded by the liver, and injected testosterone is rapidly absorbed from the injected medium and degraded/ however, from the, early 1940’s synthetic mod­ ified versions of testosterone were developed. these drugs were more resistant to degradation and were used clinically to promote muscle growth after chronic illness, as a hormone replacement therapy for hypogonadal males, and as treatment for depression. these synthetic forms of testosterone have become known as ana­ bolic-androgenic steroids (aas). given the results of the early tests which showed positive effects on muscle growth, it was not surprising that sports participants started experimenting with aas with the aim of trying to improve their physical performance.9 by 1976 aas’s reputation among athletes and officials had grown to the point that the international olympic committee banned their use. however, that has not reduced their use and currently in south africa they are being used across the spectrum from school­ children45 to elite bodybuilders'1 in an attempt to improve muscle size or strength. address for correspondence mrcajct bioenergetics of exercise research unit, department of physiology, uct medical school, observatory, 7925. phone (021) 4066-535 fax (021) 477669 email m ik elam b @p h ysio .u ct.a c.za there are many issues about drug use in sport, ranging from ethical considerations, the concept of cheating, and the problem of side-effects. it is beyond the scope of this review to discuss all these issues. the following discussion will there­ fore focus on the ergogenic and myogenic proper­ ties of aas, with the aim of developing an expla­ nation for their mode of action based on well con­ trolled mechanistic and observational studies. readers interested in the side-effects of aas are referred to hickson et al (1989) for a detailed discussion.7 do aas promote an increase in muscle mass and strength? _ _ , in a recent study 97% of all subjects who had used aas believed they had become stronger as a result of aas.1’ the perceived average increase in strength as a result of aas use was around 30%.e however, this overwhelming belief in the ergogenic properties of aas is not shared with the same enthusiasm by many scientists, proba­ bly because of the lack of sound scientific evi­ dence. this can be attributed to the inherent problems in conducting well-controlled studies on the effects of aas which has resulted in an unclear understanding of the mechanisms of action of aas administered in suprapharmalogi cal doses. inherent problems in aas experimentation ( i) blind experiments it is impossible to do a blinded experiment with subjects either using suprapharmacological doses of aas or placebos, because the subjects in the aas group will know they are using aas within a few days from the overt symptoms which they develop. this may affect the outcome of the experiment because it has been shown that ath­ letes get stronger if they believe they are ingest­ ing aas, even if they are in fact ingesting place­ bo.8 in addition, other factors which may increase strength (training intensity, motivation, nutri­ tion) are all affected by aas.9 therefore, many studies have been confounded by poor control over these factors. (ii) ethics it is illegal to provide aas to subjects in the actu­ al doses and combinations used by sports partic­ ipants. the doses used by sports participants 6 sports medicine june 1995re pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:mikelamb@physio.uct.ac.za sometimes exceed the maximum clinical doses by 18 fold,6 with potentially serious side-effects.7 therefore, the results from studies in which clin­ ical doses of aas have been used, cannot be gen­ eralised to aas use among sports participants.10 concensus studies the experimental constraints have resulted in a paucity of scientific literature on the ergogenic and myogenic properties of megadoses of aas. in a position statement in 1977 the american college of sports medicine concluded that "... there is no conclusive scientific evidence that extremely large doses o f anabolic steroids will aid or hinder athletic p e r f o r m a n c e however, the studies used in developing this position state­ ment were later criticised because many used inexperienced, untrained subjects, lacked dietary controls, used low intensity training and used non-specific forms of testing muscle strength therefore, in 1984 the acsm revised the posi­ tion statement to conclude: “anabolic steroids in the presence o f an adequate diet can contribute to increases in body weight, often in the lean mass compartment ... and the gains in muscle strength achieved through high intensity exercise and prop­ er diet can be increased by use o f anabolic steroids in some individuals”.1' subsequently, other reviews of the literature have concluded from carefully selected studies that “anabolic steroids have the most pronounced affect in those athletes who have trained to the point that they are in a chronic catabolic state”, 1:1 and “anabolic steroids may slightly enhance muscle strength in previous­ ly strength trained athletes”.10 therefore, it may be concluded from the anec­ dotal and scientific evidence that aas increase muscle mass and strength providing the athlete is (i) highly trained, (ii) training hard while using the drugs, and (iii) eating a high energy, high protein diet. the proposed mechanisms of action will now be discussed in more detail. mechanism o f action of aas (i) circulating androgens ^ e testes secrete about 5-10mg testosterone per day/ which maintains a circulating plasma con­ centration of 0.5-0.6vig/100rni.' about 40% of cir­ culating testosterone is bound to albumin and 58% to sex hormone binding globulin. the remaining testosterone is free and reflects the testosterone available for interaction with target cells.1 this concentration of circulating free testosterone remains fairly constant until the age of 50 years, after which it starts to decrease. (h) androgen receptors free testosterone binds to androgen receptors ’ located in the cytoplasm and nuclei of cells, these receptors are protein molecules and occur ui most tissues.14 androgen sensitive tissue, such as the prostate glands, may have 25 times the sports medicine june 1995 easing the aches of real effort! people who make an e ffo rt invariably feel the results. it doesn't have to stop them trying. n orflex co tablets w ill help ease muscle pain a n d sports injuries. effort free re lie f w ithout drowsiness. [s2] norflex co reference no: b1098 (act 101/1965) each tablet contains: orphenadrine citrate 35mg and paracetamol 450mg. njuuss. 3m innovation 3m pharmaceuticals s.a . (ply) ltd co. reg. no. 5 2 /0 1 6 4 0 /0 7 181 barbara rood, elandsfontein, tvl, 1406 tel: ( oi l ) 922-2081 bo h & a 688 6/js m r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) number of androgen receptors compared to skele­ tal muscle.15 aas and endogenous androgens bind with equal affinity to the receptors. tmj androgen receptors in most tissue are saturated in men with normal circulating testosterone con­ centrations,17 therefore, the number of androgen receptors may be a limiting step in aas action.18 an increase in circulating testosterone concen­ trations, for example after aas treatment, down regulates these receptors19 and a decrease in cir­ culating testosterone concentration, for example after castration, up-regulates the receptor con­ centrations.20 exercise training also increases the receptor concentrations in skeletal muscle. inoue et al., (1993) showed that the androgen receptor concentration in rat muscle increased by 25 /o three days after starting an exercise programme. however, by 4 weeks the muscles had not stopped growing, even though the androgen receptor concentration had by this time plateaued.21 the authors concluded that an increased receptor concentration is an important trigger for initiating muscle hypertrophy, but thereafter other factors are necessarily for the maintenance of the hypertrophic response in skeletal muscle. (hi) metabolic action o f androgens the generally accepted model explaining andro gen-receptor action is that the testosterone mole­ cule binds to the androgen receptor in the cyto­ plasm and induces a conformational change to the receptor. the androgen-receptor complex is translocated into the nucleus and subsequently binds to chromatin acceptor sites where it initi­ ates the transcription process, resulting in new messenger rna formation.18 after translation on ribosomes, new protein is synthesized. the nature of the protein synthesized is dependent on the target tissue. this theoretical model shows that aas exert their ergogenic and myogenic effects by stimulat­ ing protein synthesis. however, as described ear­ lier, there is a limited capacity for anabolic steroid binding to androgen receptors since the receptor number is a limiting factor and may be d o w n -regulated after aas treatment. although protein synthesis may increase slightly after aas treatment,23 this increase does not account for the total increase in muscle mass. therefore, fur­ ther explanation is required. (iv) anti-catabolic effects another mechanism for the action of aas is that they exert their effects through the glucocor­ ticoid receptor. glucocorticoids are a class of hor mones secreted mainly from the adrenal cortex during a bout of exercise or in response to any stressful stimuli. these hormones, of which cor­ tisol predominates, promote amino acid efflux from muscle and increase protein degradation.24 in essence, androgens have an anabolic, whereas glucocorticoides have a catabolic action. these catabolic processes, as a result of glucocorticoid action, seem to be exacerbated following high intensity training. the exposure to excessive training loads for prolonged periods causes the overtraining syndrome which results in elevated circulating cortisol concentrations at rest.& this causes a catabolic state in the athlete.20 there are separate receptors for androgens and glucocor­ ticoids in skeletal muscle27 28 with 20 to 100 times more glucocorticoid receptors compared to androgen receptors in muscle.-7fuj the results of several experiments have shown that androgens can compete with glucocorticoids for glucocor­ ticoid receptor binding in skeletal muscle.'4'9 this antagonism can block the action of glucocor­ ticoids, and therefore, through this process androgens have an anti-catabolic effect. the net effect of this anti-catabolism wall be to increase muscle mass. therefore, there is a strong argument that aab exert their myogenic effects, not through increas­ ing protein synthesis alone, but rather though reducing muscle breakdown. in addition, the anti-catabolic effect of aas may allow the subject to train harder without developing the overtrain­ ing syndrome. additional training alone may also stimulate muscle growth and strength. summary there is both anecdotal and scientific evidence that suprapharmacological doses of aas increas­ es muscle mass and strength in previously trained athletes undergoing intensive training and eating a diet sufficient in protein and energy. although an increase in protein synthesis con­ tributes to the increase in muscle mass and strength, it is likely that the more significant mode of action of aas is through reducing the catabolic processes which occur following inten­ sive training. references 1. schwartz, f .l . & miller, r .j . a n d r o g en s and anabolic steroids. in m od ern p h arm acology, 2 n d edition, ed s c .r . craig and r .e . stitzel, 1 9 8 2 ,-9 0 5 -9 2 4 , l ittle, b row n and c om pany, b o s to n , u s a . 2 . h oberm a n , j .m . and yesalis, c .e . the h istory o f syn th etic testosteron e. sci a m , 1 9 9 5 ;2 :6 0 -6 5 . 3 . w ilson, j .d ., & griffin, j .e . the use and m isu se o f andro qens. m eta bolism , 1 9 8 0 ;2 9 :1 2 7 8 -1 2 9 5 . 4 . schwellnu.% m.p., l am bert, m .i ., todd, m.p., & j u n t z , j .m . a n d r o g en ic anabolic stero id use in m atric pu p ils. s. a fr.m ed .j ■ 1 9 9 2 ;8 2 :1 5 4 1 5 8 . 5 s kow no,j. d r u g su rvey am ong first-tea m s ch o o lb oy rugby players. s.a fr.m ed .j . 1 9 9 2 ;8 2 :2 0 4 . 6. titlestad, s .d ., lam bert, m .i. & schwellnus, m.p. a su rvey to determ ine ty p e s and d osa g es o f anabolic androgenic steroids used b y com petitive bodybuilders in s outh africa. s .a . j .s p o rts m ed, 1 9 9 4 ;1 :2 4 -2 8 . 7. h ickson , r .c ., ball, k .l . a n d f a ld u to , m .t. a d v e r s e effects o f anabolic steroids. m ed. toxicol. a d v e r s e d ru g e xp . 1 9 8 9 ;4 :2 5 4 -2 7 1 . , 8 . a riel, g . a nd saville, w. a n a b olic stero id s: the p h ysio lo gi­ 8 sports medicine june 1995 ire pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) cal effects o f p la cebos. m ed sci sports. 1 9 7 2 ;4 :1 2 4 1 2 6 9. yesalis, c .e . a n a b o lic steroids in sport and e xercise. 1 9 9 3 ; h u m a n k in etics publishers, cham paign. illinois, u sa . 10. ela sh off j .d . jacknow , a .d ., shain, s .g . & b raunstein, ( j.d . e ffects o f anabolic-androgenic steroids on m uscular strength. a n n . intern. m ed. 1 9 9 1 ;1 1 5 :3 8 7 -3 9 3 . 11. a m erica n college o f sports m edicine. p o sition s ta tem en t on the use and a bu se o f anabolic-androgenic steroids in sports. m ed sci. sports exerc. 1 9 7 7 ;9 :x i-x ii 12. a m erica n college of sports m edicine. p o sition sta n d on the use of anabolic-androgenic steroid s in sports. a m. j. sports m ed. 1 9 8 4 ;1 2 :1 3 -1 8 . 13. h a u p t, i i .a . and r overe, g .d . a n a b olic stero id s: a review o f the literature. a m . j . s ports med. 1 9 8 4 ;1 2 :4 6 9 4 8 4 14. h ickson, r .c . & k u row ski, t.g. a n a b olic stero ids and training. clin.sports m ed. 1 9 8 6 ;5 :4 6 1 -4 6 9 . 15. k rieg, m . & voight, k .d . b iochem ica l su b stra te o f andro­ genic a ctions at a cellular level in p r osta te , bulhocaver n o su s /le v a to r ani and in skeletal m uscle. a c t a endocrinol 1 9 7 7 ;8 5 (suppl. 2 1 4 )-.4 3 -8 9 . 1 6 . sa artok. t. dahlberg, h. & g u sta fsson , j .a , r e la tive bind­ ing affinity of anabolic-androgenic stero id s: com parison o f the binding to the androgen receptors in skeletal m uscle and in p r o s ta te , as well a s to sex -b in d in g globulin. e ndocrinology. 1 9 8 4 ;1 1 4 :2 1 0 0 -2 1 0 6 . 17. wilson, j .d . a n d rog en abuse b y a thletes. endocr. r ev. 1 9 8 8 ; 9 :1 8 1 -1 9 9 . 18. snochow ski, m . w olinska-lvitort, e & p erkow ski, w .a .m . s ter o id h o rm o n e re c ep to r s in sk e le ta l m u scle. in b io ch em istry o f e xercise v i. ed s b. saltin. 1 9 8 6 ;9 5 1 1 0 , h u m a n k in etics publishers. cham paign, illinois, u s a 19. sinnet-smith, p .a ., palmer, c .a ., b u tter y. p.j. a n d rog en receptors in skeletal m uscle c y to so l fro m sh eep treated with trenbolone acetate. ilo rm . m eta b. r e s .1 9 8 7 ;1 9 :1 1 0 1 1 4 . 2 0 . r anee, n .e . & m ax, s.r . m odulation o f the cyto so lic andro­ g e n re cep to r in str ia te d m u scle b y s e x ste ro id s . e ndocrinology. 1 9 8 4 :1 1 5 :8 6 2 -8 6 6 . 2 1 . inoue, a '., yamasaki, s., fushiki, t. k a n o , t„ m oritani t, itoh , k . & sugim oto, e . r a p id increase in the num ber o f androgen receptors follow ing electrical stim ulation o f the rat m uscle. eur. j. a p p l. p hysiol. 1 9 9 3 ;6 6 :1 3 4 1 4 0 . 2 2 . g ro d y w.w., schrader. w.t., & o ’m alley, b . w. a ctiva tio n , transform ation, and subunit structure o f stero id horm one receptors. endocr. r ev. 1 9 8 2 ;3 :1 4 1 -1 6 3 . 2 3 . griggs, r .c ., k in gston , w., j ozefow icz. r .f ., herr, b .e . forbers, g & h ollid a y, d . e ffect o f testo stero n e on ’m uscle ™ m 9 6 6 4 9 8 5 0 3 e pr° tetn s^ nthesisj a ppl■ p hysiol. 2 4 . h ick so n , r .c .. czerwinski. s.m ., falduto, m .t. & young, a.p. g lucocorticoid antagonism b y exercise and andro­ gen ic-a n a b olic s te r o id s . m ed . sci. s p o rts e x e r c 1 9 9 0 ;2 2 :3 3 1 3 4 0 . ■ u z " " 1' , ' 1" ’ n o “ kes' t-d -’ l evy, w„ smith, c. & millar, r.p. h yp oth a la m ic d ysfunction in overtrained athletes. j clin. endocrinol. m ela b ., 1 9 8 5 ;6 0 :8 0 3 8 0 6 . 2 6 . k u ipers, h . & keizer, h .a . overtraining in elite a thletes sports m ed ., 1 9 8 8 ;6 :7 9 -9 2 . 2 7 . d a h lb e rg , e ., s n o ch o w sk i, m . & g u s ta fss o n , j .a . r egula tion o f the androgen and glucocorticoid receptors in skeletal m uscle cyto so l. e n d o crin olo g y 1 9 8 1 ;1 0 8 :1 4 3 1 -1 4 3 9 . 2 8 . d ube, j.y, l esag e, r .l . & tremblay, r .r . a n d rog en and estrogen binding in rat skeletal m uscle and perineal m us cles. can. j . b iochem . 1 9 7 6 ;5 4 :5 0 -5 5 . 2 9 . m ayer, m and r o sen . f. interaction o f anabolic steroids with glucocorticoid receptor s ite s in rat m uscle cutosol. a m . j. p hysiol. 1 9 7 5 ;2 2 9 :1 3 8 1 -1 3 8 6 . [ j appointment: executive editor sa journal of sports medicine sasma aims to continue to produce a journal o f international standard or its members and to create an opportunity for national researchers to publish their work. the sa journal o f sports medicine wishes to appoint a dynamic active executive editor to promote sports medicine and raise academic levels of the practicing disciplines and sporting fraternities. qualifications: mb chb, post graduate degree: sports medicine/sport science/sport physiology. publications in recognised journals. experience as editor or editorial board member recommended. curriculum vitae and certified copies of qualifications addressed to: the editorial board, dr phdda de jager, suidstr 1253, hatfield, pretoria, 0083. closing date: 30 july 1995. sports mbdicine june 1995 9 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) “ergolytic and harmful drugs in sport” d ( onstant inou . , tt̂ \ mbbch (rand) bsc(med) (hons) sport science (uc1) private practice in sports medicine_______________ ______ drugs in sport evokes certain dark images in one’s mind, with behind the scenes, secretive use of tablets and injections to improve on optimum preparation; and beat an opponent. cheating in this way may involve so-called ergogenic aids. “ergo” is derived from the greek word ergon1 and “gen” from the greek “to be produced” 1 and has come to mean any means used to enhance energy utilization (performance)." “ lytic” is an adjective for “dissolution and ergolytic therefore defines means of impairing performance. this of course is something that no athlete would deliberately or intentionally pur­ sue. even small ergolytic effects may have vastly significant effects on performance, particularly significant in elite athletes. doping control is covered elsewhere in this journal, and is necessary for several reasons. one such reason relates to the potential health risks.4 this paper highlights this aspect in relation to potential ergolytic effects and also classes of drugs that may not be banned, but may be harm­ ful to sportspeople. those drugs that have a blan­ ket banning by the international olympic committee (ioc), and sporting codes that follow those guidelines, will not be alluded to here, and will be discussed elsewhere. there are however some that are banned only in some sports, or have special conditions that may be applied: and include caffeine, alcohol, marijuana, corticosteroids and beta-blockers. these will be discussed, as they have relevance to the emphasis of this paper. it should be remembered that all drugs, by virtue of having pharmacological properties, may have side effects. it is beyond the scope of this paper to cover the vast array of these and various drug interactions, and should be referred to as necessary. a r. a some drugs may be necessary to modify dis­ eases, sustain or improve quality of life. these can be used for acute or chronic conditions, and many of these populations may be partaking in exercise. some are used only for recreational pur­ poses. address for correspondence dr d constantinou p.o. box 1171, sunninghill, 2157. tel: (oil) 883-4988. fax: (oil) 883-4980 the moral and ethical issues of the use of ergo­ genic aids has been greatly deliberated,4"’ and to extend these arguments to include ergolytic and potentially harmful drugs complicates matters exponentially. therapeutic drugs will now be discussed in alphabetic order o f class. analgesics! (see also anti-inflanxmatories) paracetamol is widely used as an analgesic due to the safety profile, and has no known ergolytic effect. high doses may lead to hepatic toxicity/’ it is often found in combination analgesics, which may contain prohibited substances. codeine is no longer banned by the ioc, and may be an effective analgesic. this too is often found in combination analgesics and remedies for the relief of common colds. high doses may lead to narcotic side effects such as nausea, vomiting, dizziness, respiratory depression, and may have addictive properties.7 8 antiarrhythinics: (see also beta-blockers, antihypertensives) often patients requiring these may be restricted form exercise for medical reasons, but others may be encouraged to exercise. these may have arrhythmias as side-effects and may impair car­ diac output with exercise and lead to hypotension and syncope.8'1 antibiotics: all classes of antibiotics have side effects that may be severe enough in some individuals to affect performance. these vary from headache, gastro-intestinal (git) disturbances, nausea, vomiting, diarrhoea and idiosynchratic reac­ tions.6 often the reason antibiotics were pre­ scribed for will limit one’s participation in exer­ cise and sport, and antibiotics per se are not con­ tra-indications to participation. anticoagulants: warfarin and heparin type anticoagulants may have significant drug interactions with non­ steroidal anti-inflammatories drugs (nsaid) and anabolic-androgenic steroids, which sportspeople may be taking. their side effects of nausea, vom­ iting, skin reactions and fat necrosis*’ may affect performance. their real dangers are that haem­ orrhage may occur. this may be secondary to acute injuries, and are therefore relative contra­ indications in collision and contact sports. in sports medicine june 1991re pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) haemorrhage may also occur in an occult form and lead to git, cystic or renal blood loss, with subsequent anaemia and impaired work capacity. antidiarrhoeals: in endurance athletes and particularly in runners there is an increased incidence of git symptoms including diarrhoea.8,10 the management may include antidiarrhoeals such as loperamide,810 h^-antagonists8 with side effects of nausea, dizzi­ ness, fatigue and allergic reactions.0 anticholinergics may be included in some prepa­ rations and cause dry mouth, blurred vision, tachycardia and urinary retention.0 antiemetics: most drugs in this class have sedation as side effects, and some have extrapyramidal neurologi­ cal impairment, both which may significantly affect performance. antiepileptics: most anti-epileptic drugs lead to poor concentra­ tion, co-ordination and cognitive function.0-8 they may also cause nystagmus, ataxia and drowsi­ ness, and therefore have special reference for participation in contact sports, those requiring fine dexterity skills and scuba diving. antihistamines: oral and injectable preparations of the older types cause drowsiness, muscle weakness, dizzi­ ness, headache, visual disturbances, dry mouth, thirst, feeling of heaviness in upper limbs, inco­ ordination, tight chest, and may precipitate con­ vulsions.6 their use will certainly lead to ergolyt­ ic effects. the newer generation long-acting forms are more selective, and are said to lack signifi­ cant sedative effects, but may still cause nausea, fatigue, dizziness, myalgia and arthralgia, and so may still have undesirable effects on perfor­ mance. topical creams may cause local irritation with minimal systemic effects, but nasal prepara­ tions may cause somnolence, headache, tired­ ness and epistaxis. antihypertensives: diuretics are prohibited by the ioc11 and may have side effects that may impair performance and be harmful to health. some of the older, non­ specific, calcium channel blockers may impair cardiac output with exercise.08 beta-blockers are banned in some sports, but may be used therapeutically for hypertension, certain arrhythmias, angina, anxiety and migraine prophylaxis.6 y they may aid in fine co ordmation sports such as archery and pistol shooting by blunting anxiety and fine tremors.48 however, reduced aerobic capacity4 and lethar­ gy’ may impair performance in endurance activi­ ties. other side effects may be risks to health and include bronchospasm, masking of hypogly caemic symptoms and adversely affecting lipid profiles,6'2 alpha-blockers may cause syncope, hypoten­ sion, acute tachycardia.09 angiotensin converting enzyme inhibitors may cause chronic cough hypotension, headache, dizziness, fatigue, dys­ pepsia, nausea and interact with nsaids.69 anti-hypereh°1 esterolacrn ics (and dyslipidaemic modifying drugs) there are various classes of such drugs, and have important implications as people talcing these are (or should) be participating in controlled or supervised exercise programs. the following side effects may affect performance. fibrates git disturbances, sweating, nausea, arrhythmias, blurred vision, fluid retention, headache, dizziness.6'8 nicotinic acid abdominal pain, hyperglycaemia, hyperuricaemia (?gout), blurred vision, hypotension. hmgcoa reductase inhibitors nausea, consti­ pation, headaches, insomnia, myal­ gia, muscle stiffness, postural hypotension and peripheral neuropa­ thy. probucol diarrhoea, abdominal pain, arrhyth­ mias, hyperuricaemia. anti-inflammatories: non-steroidal anti-inflammatories are used extensively by sportspeople in prescription and over the counter formulations. they function by inhibiting prostaglandin production46813 and are used mostly for acute injuries, some believing in their use for fractures and chronic injuries too.4 among the side effects that are significant and dangerous are git blood loss,7814 peptic ulcera­ tion (often asymptomatic)8 and renal damage with acute tubular necrosis and renal failure.7813 this is particularly of risk in the presence of de­ hydration. other side effects include broncho­ spasm, tinnitus, allergic reactions, headaches and hepatic dam age/8 some have strong anal­ gesic properties and partaking in exercise or sport under their influence of analgesia (or com­ bined with analgesics) may w7orsen injuries and increase the risks for other injuries. under these exercising conditions the risks for git haemmor rhage, diarrhoea and renal damage are particu­ larly high. aspirin may have all the above prob­ lems and in addition has strong anti-platelet adhering properties, which may lead to increased bleeding in acute injuries.0 8 use of aspirin in chil­ dren has the risk of reye’s syndrome, \vh ich may be fatal.34 some of the drugs and formulations report fewer side effects, but are all still at risk of the above. topical nsaids (gels, creams, ointments, tran scutaneous patches, sprays) can lead to systemic effects if used in high doses, frequently or for prolonged periods of time. corticosteroids have potent anti-inflammatory properties with little data supporting their bene­ fits in most acute or chronic sports injuries, but sports medicine june 1995 11re pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) have significant side-effects.4" inhaled corticos­ teroids and topical preparations are permitted by the ioc (with written mcdical support) and the small doses have few side effects."" oral and injectable forms interfere with collagen synthesis and may lead to poor tissue healing, with in­ creased risks o f further injury. t he systemic cata­ bolic effects may impair performance and the side effects include myopathies, fluid retention, immunosuppression, electrolyte disturbances, inhibition o f growth, git disturbances and bleeding.4'*78 antimalarials: these are often taken by sportspeople travelling to compete. most antimalarial drugs may cause git side effects with abdominal pain, nausea, vomiting and diarrhoea; which may affect perfor­ mance.1' these are often transient and in general are not a problem. mefloquine has neurological and neuropsychiatric disturbances that makes it the only anti-malarial drug contra-indicated in scuba diving. anxiolytics: these may affect psychomotor skills, reaction time, cognitive function, level o f wakefulness and thermoregulation™ and can therefore be ergo lyt­ ic and increa.sc risks o f injury. these and other psychoactive drugs arc definitely contra-indicat­ ed with scuba-diving, and can be life-threaten­ ing.1 haeinatinics (and iron supplements): these can lead to git disturbances, nausea, vomiting, abdominal pain and constipation.1'they will however tend to have an improving perfor­ mance effect as the anaemia is corrected. hypoglycae mics: as with hypertension and dyslipidaemias, dia­ betics often include exercise as part of their man­ agement protocol. oral hypoglycaemics may cause git disturbances, headaches and dizzi­ ness." these and insulin may cause hypogly caemia, and exercise prescription in diabetics should address the issues o f nutrition, timing o f taking insulin/medication, intensity and volume o f exercise. as a rule insulin dependent diabetics should not partake in scuba diving. recreational habits may include the use o f ergolytic substances or harmful drugs. here ref­ erence is made in alphabetic order of substance. alcohol: the ioc bans alcohol in riflery'81” lor the obvious dangers, and has special considerations for other sports. several sports ban alcohol, and locally basketball south africa has recently baimed its use (personal communication). there has been no evidence o f ergogenic effects, but there may well be ergolytic effects with alcohol intake. certainly there are health risks with abuse. alcohol may cause hypoglycaemia by reducing glucose release from the liver,7 cause diuresis by reducing vasopressin secretion’0 and impairing psychomotor ability, memory and decision mak­ ing skills, up to 48 hours after ingestion,'7 with obvious consequences. alcohol may also have addictive properties.471721 caffeine: although a stimulant and banned in certain quantities by the ioc,47811 it is included here b e­ cause it is often taken recreationallv in coffee and colas. no studies have shown significant improved physiological performance in smaller doses,' but the side effects may in fact impair performance, and include irritability, anxiety, insomnia, palpitations, headache, diarrhoea, hypertension and diuresis.8" '17 in high doses there have been reports o f seiziue, coma and even death.18 tobacco: smoking tobacco may have deleterious effects on physical perform ance.7 this common habit affects mucous membrane cilia function and mucous production with increased incidence of dyspnoea and coughing with exertion.7 carbon monoxide has a 300 x affinity for oxygen over haemoglobin (hi)) and smokers o f 15-25 ciga­ rettes per day can have 6-7% carbon monoxide combined to hb. this may significantly affect physical exertion and this together with mucous plugging and air trapping may lead to increased risks o f gas embolism in scuba divers. nicotine is readily absorbed and although undergoes hepatic metabolism and excretion, can lead to increased adrenaline and noradrenaline with tachycardia and hypertension for several hours after smoking.7'" for this reason alone smoking should be discouraged for 24 hours before competition. nicotine also has addictive properties.7 tar is also a respirator)irritant and carcinogen. the risks o f passive smoking arc voub iw i 0750 diclophenac sodium 50 mg k/3.1/253 sports medicine june r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) o n -th e -s p o t pain re lie f. • for muscular pain • effective pain relief site specific non-staining • non-greasy reparil-gel relieves muscular pain. ******* v> m e d a l s ; m a d a u s p h a r m a c e u t i c a l s ( p t y ) l t d ' ■ ' x ! ' ° ' ; 7 7 / 0 0 1 7 4 / 0 7 2 n d r o a d <c n r 1 6 t h r o a d ) , r a n d j e s p a r k , m i d r a n d 1 6 8 5 reparil -gel 100 g conta.ns: aescin 1,0 g; d.ethylamine salicylate 5,0 g. reg. no. g/13.9/2367 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) becoming more recognised and may have signifi­ cance in team sports. chewing tobacco excludes the inhalation problems of carbon monoxide and tar, but there are local irritant and potential car­ cinogenic effects. nicotine is still absorbed, causing its effects. smoking is also a well recognised risk factor for coronary heart disease and will therefore increase the risks of sudden death while exercis­ ing.7'8,23 marijuana: this is legally prohibited in south africa and can lead to criminal charges if found to have this in one’s possession. the ioc has special considera­ tio n s /11 and is found to be widely used through­ out africa,23 use of marijuana may affect judge­ ment and performance.*'the addictive proper­ ties7 and disinhibited motivation effects8 can affect an athletes performance and indeed career. the issue of passively inhaling marijuana has been raised and has interesting implications. as a general rule any drug has the potential to affect performance, and seemingly innocuous drugs may in some individuals or conditions have severely undesirable effects. a case in point is scuba diving, where relatively harmless drugs may have unpredictable effects under hyperbaric conditions. just as athletes, coaches and health care pro­ fessionals should as a rule ensure any medication taken has no banned substances, so they should ensure there are no ergolytic or potentially haz­ ardous consequences. references 1. f o w le r f .g , f o w le r h . w ( e d s ) . t h e o x ford h a n d y d iction a ry (6 th e d ) . l ond on, o xford u niversity p ress, 1 9 9 1 . 2 . w illia m s m .h . e r g o g e n ic a n d e r g o ly tic s u b sta n c es. m ed .s ci.s p .e x . 1 9 9 2 ;v o l 2 4 , n o .9 supplem ent. s 3 4 4 -s 3 4 8 . 3 . d o r la n d ’s p o c k e t m ed ica l d ic tio n a r y ( 2 3 r d e d ) . philadelphia, w b .s a u n d ers, 1 9 8 2 . 4 . c an tu r .c , m ic h e lil .j . ( e d s ) . a m erica n college o f sports m edicine g uidelines fo r the team p hysicia n. pennsylvania, l ea and fabiger, 1 9 9 1 . 5. c onsta ntinou d . a n a b olic steroids — a c ontem pora ry p erspective (le tte r ). s o u th .a fr.j .m ed . vo l.8 6, no 4 . a p ril 1 9 9 5 ;2 9 0 -2 9 1 . 6. h o ld e r n e ss m , s tra u g h a n j .l ( e d s ) . s o u th a fric a n m ed icines f orm ularly (2 n d e d ) . d ep t. pharm acology, univ. c ap e town, m a s a publ., 1 9 8 9 . 7. p eterson l , r en stro m p. sports injuries: their prevention and treatm ent. c ap e town, j u ta and co. 1 9 8 6 ;1 6 ,1 6 7 . 8 . b rukner p, k h a n k . clinical s ports m edicine. sydney, m cgraw -h ill, 1 9 9 3 ;1 0 5 ,5 0 4 6 5 ,5 9 8 ,6 0 0 ,6 0 9 ,6 7 0 8 8 . 9. o verview o f the r ecom m en d a tio n s fo r a n tih yp erten siv e therapy the f ifth report o f the j oin t n ational c om m ittee on the d etection , e valuation and treatm ent o f h ig h b lo o d pressure. a r c h .in t.m e d . 1 9 9 3 ;1 5 3 :1 5 4 -1 8 3 . 1 0 . schw artz p.a. garisch j .a .m . clinical approach to the diagnosis and m ana gem ent of ga strointestinal s y m p to m s in endurance athletes. s o u th .a fr.j .s p orts.m ed . vol 2, no 1, m arch 1 9 9 5 ;1 0 -1 5 . 11. procedural g uidelines fo r d o p in g control; international a m a te u r a th le tic s federation. london, a u g u s t 1 9 9 3 . 1 2 . s koog i et al. a n tih yp erten siv e therapy ( a c e inhibitors and b e ta blockers) effects on seru m triglycerides and h d l cholesterol pre-and p o s t exercise training in mildly hyper­ tensive males. m ed .s ci.s p .e x . supplem ent to vol 2 6 , no 5. m a y 1 9 9 4 ;5 3 9 . 13. n o a k e s t .d . l o r e o f r u n n in g . c a p e tow n, o xford , 1 9 9 2 ;5 8 6 ,5 9 0 . 1 4 . schw artz p .a, schwellnus m.p, k o e r ts a .j . the incidence and risk fa c to rs o f g a stro in testin a l s y m p to m s in six endurance sp orts. sou th .a fr.j .s ports. m ed. vol 2 , no 1, m arch 1 9 9 5 ; 1 7 -2 4 . 15. k a y l e a . safe d ivin g: a m edical handbook fo r scu b a divers. london, viking, 1 9 9 4 ;5 7 ,1 7 1 . 1 6 . engels h .j , wirth j .c , l avine s.j. caffeine effects on glob­ al blood flow, left ventricular perform ance and blood p r e s ­ sure a t rest and during light p h y sica l work. m ed .sci.sp.e x. supplem ent to vol 2 6 , no 5. m a y 1 9 9 4 ;5 3 8 . 1 7 . i la u p t h .a . d r u g s in a th le tic s: clinics in sports m edicine, vol 8. no 3 , j u ly 1 9 8 9 ,5 6 1 -5 8 1 . 18. wagner j .c . e n h a n cem en t o f athletic perform ance with drugs (r e v ie w ) sports.m ed . 1 9 9 1 :1 2 ;2 5 0 2 6 5 . 19. the use o f alcohol in sports. m ed .s ci.s p.e x. vol 1 4 no 6 1 9 8 7 ;ix -x i. 2 0 . g a nong w.f. r eview o f m edical p h y sio lo g y ( 1 6 t h e d ) . n ew j ersey, prentice-h all int. 1 9 9 3 ,2 8 2 -2 2 2 . 2 1 . williams m . n utrition f o r fitn e ss and sport. d u b u qu e la, w.c. b row n 1 9 9 2 . 2 2 . c o n s ta n tin o u d . s p o rt a n d su d d en d e a th . m ed .a ss .s o u th .a fr. southern t v l branch, a u g . 1 9 9 2 . 2 3 . lam bert m . p roceedings o f 6 th s outh a frica n sports m ed icine a s s o c ia tio n in tern a tion a l c on g ress. durban, m arch 1 9 9 5 . ch 14 sports medicine june 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) verbode middels in sport: resultate van toetsing vir die tydperk 1986-1994 pj van der merwe phd nat sci, departement farmakologie, universiteit van die oranje vrystaat abstract screening procedures were performed on 5 714 urine specimens collected from competitors in 43 different sports during the period 1986-1994. samples were tested by gas chromatography and gas chromatography/mass spectrometry for the presence of stimulants, narcotics, anabolic steroids, diuretics and 13-blockers. drugs classified as forbidden substances by the international olympic committee were detected in 196 (4.17%) of the samples. anabolic steroids were detected in 86 (43.9%) of the sam­ ples and stimulants in 82 (41.8%). the anabolic steroid most frequently detected was 19 nortestosterone while the stimulant was fencam famine. the ephedrine’s as a group accounted for 52 (61.5%) of the positive stimulant samples. this high incidence of the use of banned sub­ stances indicates that the dope testing pro­ gramme to curb use of banned substances by competitors in sport should continue and be expanded to all sport. inleiding in 1983 is die eerst toetse vir die gebruik van ver­ bode middels in sport in suid-afrika gedoen toe die departement farmakologie aan die universi­ teit van die oranje vrystaat urienmonsters geanaliseer het vir ’n beperkte aantal stimu­ lante.1 sederdien is die analitiese metodes sodanig ontwikkel om vir al die groepe middels wat deur die intemasionale olimpiese komitee (iok) as verbode geklassifiseer is, te kan toets. hierdie groepe middels sluit in stimulante, anaboliese steroiede, narkotiese analgetika, diuretika en j3 blokkeerders. tans voldoen hierdie laboratorium aan intemasionale standaarde en is ’n ten voile geakkrediteerde laboratorium van die iokdie posadres dr p j van der merwe, dept farmakologie, universiteit van die oranje vrystaat, posbus box 339, bloemfontein, 9300. tel (051) 405-3269. fax (051) 47-1779. enigste in afrika en, benewens australie, die tweede in die suidelike halfrond. hierdie verslag handel oor die resultate van die afgelope 9 jaar van toetsing in suid afrika. metode urienmonsters is ontvang vanaf 43 verskillende sportsoorte in suid afrika. die urienmonsters is versamel deur die betrokke sportliggame in die envopak houers en daama versend na die labora­ torium. elke urienmonster is in duplikaat ver­ samel, ’n a-monster en ’n b-monster. die a-mon ster is geanaliseer vir die teenwoordigheid van verbode middels2'4 terwyl die b-monsters gevries is by -20 °c vir moontlike latere analise. indien die resultate van die siftingsprosedures aangedui het dat ’n verbode middel teenwoordig mag wees is bevestigingsanalise op die a-mon­ ster uitgevoer volgens ’n intemasionale aanvaar de protokol.° sodoende is onteenseglike bewys gelewer vir die teenwoordigheid van die betrokke middel. resultate en bespreking in die tydperk 1986-1994 is altesaam 5 .7 1 4 urienmonsters geanaliseer, die resultate word aangetoon in tabel 1. daar was ’n afname in die aantal positiewe monsters en in 1994 was die persentasie positiewe monsters feitlik gelyk aan die van die iok geakkrediteerde laboratoriums vir 1992. tabel 2 gee ’n ontleding van die verbode middels in hulle onderskeie groepe. ’n totaal van 204 verbode middels is geidentifiseer in 196 irrienmonsters wat daarop dui dat sommige urienmonsters meer as een groep verbode mid dels bevat het. soms is meer as een middel binne ’n groep in een urienmonster aangetoon. tot vier anaboliese steroiede is in sekere urienmonsters geidentifiseer. van die 196 positiewe monsters het 86 (43.9%) anaboliese steroiede bevat en 82 (41.8%) stimulante. dit is interessant om hierdie resultaat te vergelyk met die van die een-en twintig iok geakkrediteerde laboratoriums. hulle syfers wys dat 552 (68.9%) van die 805 positiewe monsters anaboliese steroiede bevat het en 221 (27.5%) stimulante. uit tabel 2 blyk dit dat die afname in die aan­ tal positiewe monsters oor die laaste 2 jaar hoof saaklik toegeskryf kan word aan die verminder ing in die aantal urienmonsters wat anaboliese sports medicine june 1995 15 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) stcroi'cde bevat het. die afleiding kail gcmaak word dat die slreng optrede teen deehiemers wat hnl skuldig maak aan die gebm ik van verbode m iddels (tot 4 jaar skorsing iiit enige kom petercnde sport vir ’n steroied positief) die nodi ge uitwerking het. dit soil egter verkeerd wees om hierdie afhame slegs aan die rede toe te skrvf aangesien sommige sportsoorte waar die deehie­ mers beskou word as potensicle hoe gebruikers van anaboliese steroiede nie die afgelope 2 jaar toetse laat doen het nie. dit word ook verder ver moed dat die werklike gebruik van anaboliese steroiede veel lioer mag wees as aangedui in tabel 2. die vinnig-werkende steroiede, veral die oralc preparate, word goner uit die liggaam uit geskei en sal dus nie meer tj’dens kompetisie in tabel 1 resultate van die toetsing vir verbode middels in sport in slid afrika in dee tydperk 1986-1994 jaar aantal aantal totale positiewe byeenkomste monsters monsters aantal % 1986 16 152 8 5.3 1987 17 161 6 3.7 1988 19 230 12 5.2 1989 33 330 18 5.5 1990 41 482 27 5.6 1991 55 711 42 5.9 1992 129 1 472 52 3.5 1993 104 1 254 21 1.7 1994 103 922 10 1.1 totaal 5 714 196 4.17 1992* 84 088 805 0.96 * io k geaklcrediteerde laboratoriums (n~21) die liggaam teen woo rtlig wees nie en sal dus nie denr die toetse aangetoon kan word nie. dit moet in gedagte gcliou word dat anaboliese steroiede as “ oefeningsniiddcls” beskou word wat lioof saaklik in die voorbereidiug seisoen gebruik word en dus nie nicer noodwendig tydens kom petisie in die liggaam teenwoordig is nie. dit beklemptoon die belangrikheid van buite-kom petisic toetsing wat internasionaal op groot skaal toegcpas word in ’n poging om die misbniik van anaboliese steroiede aan bande te le. meer as 40% van die aan till toetse wat deur die iok geaklcrediteerde laboratoriums in 1992 gedoen was, was biute-kompetisie toetse. hierdie soort toetsing word nog nie em stig in suid alvika toegcpas nie. tabel 3 toon dat nandroloon die anaboliese steroied is wat die mceste in die urienmonsters voorgekom het. dit moet tocgcskryf word turn die uuigwerkendheid van hierdie preparaat. in tabel 3 word ook ’n vergelyk gcmaak tiissen suid alrika en internasionaal ten opsigtc van die aan­ tal steroiede as ’n persentasie van die totale aan­ tal steroiede wat in die urienmonsters voorgekom het. tabel 4 toon dat fenkamfamien, wat in die skedule 5 tonikiun rcactivan® voorkom, die stim­ ulant is wat die mceste aantal kere in die urien­ monsters voorgekom het. dit wys op die gewild licid van hierdie tonilaun onder deehiemers aan konipctercnde sport. hierdie m iddcl word egter nie internasionaal veel as ’n positief gevind nie. die efedriene as ’n groep nl. efedrien, psendo cfedrien, fenielpropanolaniieii en norpsendo efedrien was verantwoordelik vir 52 (61.5%) van die positiewe stimulant monsters. hierdie svfer vergclvk redclik goed met die 46.2% wat intema sionaal gevind word. tabel 5 toon dat die efedri­ ene in al 9 jaar ’n groot bydrae gcmaak het tot die t a b e l2 verdelevg van dee aantal monsters wat verbode middels bevat in dee verskillende groepe jaar sti ni ul ante narkotiese anaboliese diuretika 3-biokkers ander to (aid analgetika steroiede 1986 7 0 1 0 0 0 8 1987 4 0 2 0 0 0 6 1988 4 3 7 0 0 0 12* 1989 10 2 6 0 0 0 18 1990 14 1 13 0 0 0 27* 1991 18 3 18 0 0 5** 42* 1992 12 6 29 0 5 0 52 1993 9 2 8 2 3 0 21 * 1994 4 1 2 3 0 0 10 totaal 82 18 86 5 8 5 196 1992*** 221 72 552 47 10 2 * * 805* * sommige urienmonster het meer as een verbode iniddel bevat ** probenesied as maskeermiddel *** io k geakkrediteerde laboratoriums (n = 21) 16 sports medicine june 1995re pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) verw. n r . g 2963 ( ^ c t / w e t 101, 1« ! celestone® § soluspao® s ml sterile multiple dose vial reg. no. c e le s to n e * s o l u s p a n * 2 ml sterile multip dose vial ,i> (act/wet 101,19*51 u c e l e s t o n e ® ;< s o l u s p a n ® i ̂ 1 ml ampoule not iv scherag (pty) limited r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) t abel3 anaboliese steroiede geidentifiseer naam aan till nandroloon testosteroon metenoloon (primobolan®) okslmetoloon (anapolon®) boldenoon* oxandroloon* * stanozolol** dianabol* * mesteroloon (proviron®) drostanoloon* * metieltestosteroon probenesied* * * presentasie van totale aantal steroiede sa iok 72 62.0 29.9 12 10.2 33.9 10 8.5 9.4 8 6.8 1.1 7 3 2 1.7. 9.4 1 0.8 8.0 1 1 1 5 * slegs vir veterinere gebruik * * nie in stud afrika geregistreer me *** gebruik as maskeermiddel vir anaboliese steroiede _________________ tabel 4 ander verbode middels geidentifiseer groep naam aantal presentasie van aantal stimulante sa iok stimulante fenkamfamien 26 30.2 1.4 fenielpropanolamien 18 20.9 10.4 pseudoefedrien 16 18.6 25.8 efedrien 15 17.4 10.0 prolintaan 4 norpseudoefedrien 3 amfetamien 3 3.5 12.2 metielfenidaat 1 narkotiese kodeiien* 16 analgetika propoksifeen 2 diuretika hidrochlorotiasied 3 furosemied 2 b-blokkers propranolol 5 sotalol 1 oxprenolol 1 atenolol 1 * word sedert 1994 nie meer as ’n verbode middel geklassifiseer nie. tabel 5 aantal monsters wat efedriene bevat jaar aantal presentasie van totale aantal positiewes 1986 5 62.5 1987 1 16.7 1988 2 16.7 1989 8 44.4 1990 8 29.6 1991 11 26.2 1992 10 19.2 1993 4 19.0 1994 3 30.0 totale aantal positiewe monsters. hierdie ver bindings word dikwels aangetref in vele verkoue, griep en hoes niedisynes en kan sonder ’n voor skrif van ’n medikus in apteke gekoop word. dit veroorsaak dat sommige deelnemers medisynes gebruik sonder om te besef dat dit verbode mid dels bevat. die onus rus egter op die deelnemers self om toe te sien dat hulle nie enige medisyne kort voor ’n kompetisie gebruik wat verbode mid dels bevat nie. onkunde word nie as ’n verskon ing aanvaar as ’n urienmonster positief toets nie. gevolgtrekking hierdie resultate toon dat: 1 sportliggame in suid afrika moet voortgaan met ’n verbode middel toetsingsprogram en dat so ’11 program vir alle sportsoorte in suid afrika moet geld. 2. inligtingsen opvoedingsprogramme ingestel moet word om deelnemers, afrigters en sport administrateurs in te lig oor verbode middels en die gevare aan die gebruik daarvan. 3. geneeshere bewus moet wees daarvan dat sommige griep-, verkoue en hoespreparate verbode middels bevat en dus nie deur deel­ nemers gebruik mag word kort voor of gedurende sportbyeenkomste nie. 4. ’11 program van buite-kompetisie toetsing deur alle sportliggame in suid afrika ingestel moet word. literatu u rverwyssings 1 h u n d t h k l , van der m erw e pj, van velden dp. d ra g s in sp ort: a report o f laboratory investigations into the preva­ lence o f their itse in south a frica. s a f r m ed j 1 9 8 4 , 00. 8 7 8 -8 8 8 . „ . , . , l h o d shin i i. kant] b, park j. s y stem a tic a nalysis oj stim ula nts and narcotic analgesics b y g a s chrom atography with nitrogen-specific detection and m ass sp ectrom etry. j a n a l toxicol 1 9 9 0 ; 1 4 : 7 3 -7 0 . 3. charui b , c h oo iip, k im t, e o m k . k w o n o, suh j, et a l a r u d ysis o f anabolic steroids using g c /m s w ith selected ion monitoring, j a n a l toxicol 1 9 9 0 ; 1 4 : 9 1 -9 5 . 4. h a tto n c k , catlin d h . d etection o f androgenic anabolic steroid s in urine. ther d ru g m on it 1 9 8 7 ; 7: 6 5 5 -0 6 8 . 5. van der m erw e p j and k ru ger h s l . d r u g s in sport re su lts o f the p a st 0 yea rs o f dope testin g in sou th africa, b a fr m ed j 1 9 9 2 : 8 2 : 1 5 1 -1 5 3 . 1— 1 2. 18 sports medicine june 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) relationship between psychological factors and injuries in a non-contact sport m marthinus ma, university of stellenbosch jr potgieter phd, university of stellenbosch abstract the incidence and perceived impact of injuries sustained by forty-four athletes were monitored during a competitive season of road running in order to ascertain relationships between illness/ injury and selected psychological factors. no sig­ nificant relationships were found between ill­ ness/injury and the psychological variables of locus of control, extroversion, neuroticism and life events. modest, but significant relationships were present between competitive anxiety, daily hassles and illness/injury. these results under­ line the desirability for athletes to acquire coping skills. key words: sports injuries, road running, stress. introduction in addition to obvious physical reasons, psycho­ logical factors may also play a role in the occur­ rence of sports injuries. for example, the rela­ tionship between personality and injury has been the subject of earlier research. however, results have been inconsistent. (brown, 1971; irvin, 1975; jackson, jarret, barley, kausch, swanson & powell, 1978; 1982; passer & seese, 1983; valliant, 1981). the relationship between stressful life events and sports injuries became the focus of more re­ cent research. in 1970 holmes reported that football players scoring high on the social read­ justment rating scale (srrs) were more likely to get injured than their low-scoring team-mates (andersen & williams, 1988). bramwell, masu da, wagner and holmes (1975) adapted the srrs for use in a sports setting and found simi­ lar results to holmes among football players. in more recent studies, coddington and troxell address for correspondence prof. justus potgieter, department o f human movement studies, university o f stellenbosch, stellenbosch 7600. tel (021) 808-4915. fax (021) 808-4817. e-mail jkp@maties.sun.ac.za (1980) reported an increase in injuries among high-school football players as a result of factors such as stressful family events. cryan and alles (1983) also found a higher rate of injury among high-stress football players when compared to lowr-stress players. hardy, richman and rosenfeld (1991) concluded that injury rate increased with an increase in life events and a decrease in social support. passer and seese (1983) made a distinction between positive and negative life events and found a relationship between negative life events and football injuries. this relationship did not apply to positive life events. although the life events/stressi n jury relation­ ship has been established in football, it is not so clear-cut whether this also holds for non-contact sports (hard)7 et al., 1991). kerr and minden (1988), in one of the few7 studies dealing with non-contact sport (gymnastics), found that timing of injury7 was related to impending competition wi th an increase in injury rate as the competition drew7 nearer. they suggested that this pattern could be attributed to heightened stress associ­ ated with the impending competition. the study of kerr and minden (1991) is significant, but the results do not concur w7itli those of williams, tonyman and wadsworth (1986), who found no relationship between life stress and injury in another non-contact sport, namely volleyball. one of the possible shortcomings of earlier research is the focus on major life events, to the exclusion of the stress caused by minor daily problems or irritations. it is hypothesized that these everyday stressful events decrease the ath­ lete’s coping ability and consequently increase the incidence of injury (miller, vaugh & miller, 1990). the study of the relationship of stress and injur)7 would be incomplete without considering personality7 variables (williams & roepke, 1993). the purpose of this study was to ascertain the relationship between illness/injtuy and selected moderator personality factors and life stressors in a non-contact sport by monitoring athletes throughout a competitive season. this method of investigation differs from most previous studies, where factors such as life stressors were investi­ gated post hoc only after the occurrence of the injury. sports medicine june 1995 19 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) mailto:jkp@maties.sun.ac.za method sample a group o f 37 male and 7 female competitive road limners (mean age 24.4 vr) was used in this study. the sample consisted o f experienced run­ ners, ranging from provincial, national athletes to an olvmpic silver medalist, who competed in a four month winter league. instruments the following questionnaires were mailed to the runners: sport competition anxiety test (scat) (martens, vealey & burton, 1990) this 15 item questionnaire assesses differences in competitive trait anxiety, or the tendency to perceive competitive situations as threatening. the internal-external locus of control scale (rotter. 1966) locus o f control is a personality trait dealing with the degree to which individuals view their lives and siutoimdings as under their personal con­ trol. individuals who function on an internal locus o f control believe that they can control their destiny on the bases o f relatively permanent per­ sonal abilities and efforts. the i-e scale compris­ es 29 pans o f items. the score is the total mun ber of external choices made by the respondent. eysenck personality inventory (eysenck & eysenck, 1964) the epi measiu-cs personality on two dimen­ sions, namely introversion-extroversion and neu roticism-stability. extroverts tend to be outgoing, impulsive and uninhibited and like to take part in group activities. introverts are usually quiet and introspective. persons scoring high on the neuroticism scale are emotionally unstable and tend to overreact to everyday events. they fre­ quently complain o f vague somatic problems and tend to worry excessively the social readjustment scale this scale, developed by holmes and rahe (1967), ranks the magnitude o f various life change events. a preset numerical weighting is given to each event on the presumed degree of the adaptation required by a typical individual. respondents indicated the frequency o f each event during the past three months. because some events are o f a personal and confidential nature, the values awarded to life events were relatively reduced to simplify calculating the fmal score. respondents were requested to complete the questionnaire, calculate their score them­ selves and return only the fmal score. they were instructed to destroy the completed question­ naire. daily hassles sccde (kanner, coyne, schaefer & lazarus, 1981) a list o f daily hassles was presented to respon­ dents on two occasions (approximately three weeks after the commencement o f the study and three weeks before the end oi the season). respondents checked the items for personal rel­ evance and indicated the degree to which they were negatively affected on a 7-point likert type scale ranging from (“ little negative influence” to “ excessive negative influence” ). examples o f daily hassles are: losing your keys, having to wait a long time for somebody, malfunctioning o f a household appliance. respondents could also report their own personal hassles. the number o f hassles reported was multiplied with the rating o f negative influence to calculate a total score. the stun o f the totals of both lists was used in the analysis o f data. injury report forum this questionnaire was administered 5 times at regular intervals (approximately every three weeks) during the season. respondents were asked to report the incidence o f personal illness/ injury. respondents indicated the date and nature o f illness/injury as well as its perceived severity on a 7-point likert-type scalc ranging from “ not at all serious” to “very serious” . the number o f illnesses/injuries was multiplied with perceived seriousness to calculate a total ill­ ness/injury score. the sum o f the scores of the five reports was used in the final analysis ol results. results a distinction was made between illness (e.g. in­ fluenza) and injury. a total o f 58 illnesses/injuries were recorded over a period o f four months. all of the subjects suffered some form o f illness or another during the coiuse o f the season. only 7 (16%) o f the 44 athletes enjoyed an injury-free season. the following were the most prevalent ill­ nesses/injuries reported: common cold (13), call muscle injury (7), influenza (6), knee injury' (5), hamstring injury (4), achilles tendonitis (3), iliar tabular band syndrome (3), and groin injury (3). wilsenach 9 3 06 2sf m t a n e n s m o diclophenac sodium 100 mg m/3 1/63 o l o 1/m 20 sports medicine june 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) the notable absence o f shin splints among this group of iimners cannot be explained. the rela­ tionship between the psychological variables o f competitive anxiety, locus o f control, extrover­ sion, neurotic ism. and il hi ess/injury scores was investigated (table 2). a significant, but modest correlation, was found between competitive anxi­ ety and the com bined illness/injury scores (r=.313; p<.05), as well as the injury-only scores (r=.302; p<.05). the data revealed an interesting positive relationship between competitive anxiety (scat) and daily hassles scores (r=.464; p<.001). no significant relationships were found between the other variables and illness/injury scores. table 1 correlations (pearsons’s r) between psychological variables and illness/ in jury combined injuries illnesses/injuries only scat .313* .302 locus o f control -.009 .117 extroversion .183 .109 neuroticism .123 .087 life events .103 -.027 daily hassles .334* .299 * p < 0.5 the effect o f life events and daily hassles on ill­ ness/ injury was investigated further. the median score o f the sample for the combined illness/in­ jury scores was /, while the median for injuries only, was 3. the median scores were used to divide the sample into two groups, viz. a high ill­ ness/ injury group (scores above the median) and a low illness/injury group, who produced scores at and below the median. no significant differ­ ence was found between the mean scores o f the high injury and low injury groups regarding life events (table 2). however, the high injury group produced significantly higher daily hassles scores than the low injury group, both in terms o f combined illness/injury and injury only scores (table 3). table 3 comparison of injitry-only scores of low and high injury rate road _________________ ri7nners________________ variable n mean sd t p life events low rate 24 31.00 17.93 0.123 .903 high rate 20 30.35 16.79 daily hassles low rate 24 58.21 33.26 2.098 .042 high rate 20 78.20 29.14 no significant relationships were foimd between life events and the number o f combined illness/injuries (r=.l45; p>.10). when anah'sing the total illness/injury scores (which take into consideration the incidence and perceived impact o f illness/injury), no significant relation­ ship was found with life events scores (r=.103; p>.10). however, significant relationships were found between daily hassles scores and com ­ bined illness/injury scores (r=.334; p<.05) and injury only scores (r=.299; p<.05). conclusion with the exception o f competitive anxiety, the results o f this study did not indicate significant relationships between the psychological vari­ ables under investigation, namely locus o f con­ trol, extroversion, and neuroticism. the failure to find a relationship between locus o f control and the incidence o f illness/injury is consistent with the results o f earlier investiga­ tions (lysens, amvelle & ostyn, 1986; passer & seese, 1983). the relationship between competi­ tive anxiety and illness/injury partly supports the findings o f blackwell and mccullagh (1990), who concluded that competitive trait anxiety influ­ ences the severity but not the frequency o f injury. however, in the present study, there may have been an overlap in the effect o f anxiety and daily hassles scores and consequently both these vari­ ables could possibly explain a significant portion o f variance in illness/injury occurrence. the injury/illness could render the athletes sensitive to daily hassles rather than the converse. the failure o f the present investigation to find a relationship between major life events and ill­ ness is not consistent with the earlier findings o f kerr and minden (1988) with gymnasts. the ret­ rospective design o f the gymnastic studies may account for these inconsistencies. table 2 comparison of combined illness/injury scores of low and high illness/injury rate road runners variable n mean sd t p life events low rate 24 8.13 16.88 high rate 20 33.80 17.55 1.09 .282 daily hassles low'rate 24 57.75 31.34 high rate 20 78.75 31.22 2.22 .032 sports medicine june 1995 21re pr od uc ed b y sa bi ne t g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) a problem in studying mid tipi e moderator vari­ ables is the need for large sample sizes. this would necessitate investigations that cover larger groups in diverse geographical areas. in addition, in order to gather objective data, rather than sub­ jective and retrospective information, a more stringent method o f recording illness/injury inci­ dence is needed than utilising the personal re­ ports o f the athletes themselves. despite the failure o f this investigation to unequivocally identify the moderator psychologi­ cal variables associated with injury, the associa­ tion found between daily hassles and illness/in jury points to the importance o f coping resources in the stress-illness relationship. coping re­ sources comprise a variety o f behaviours and social support systems that assist the individual in dealing with life’s day to day problems. the presence o f a supportive social network o f family, friends, coach and team-mates may have a posi­ tive effect on the stress-injiuy relationship. it is therefore desirable to assist athletes psychologi­ cally to counter the effects o f daily stress. references a n d ersen m b, & w illiams j m ( 1 9 8 8 ) . a m odel o f s tr ess and athletic injury: prediction and prevention. journal o f sport and exercise psych ology, 10, 2 9 4 -3 0 6 . blackwell b . & mccullagh p ( 1 9 9 0 ) . the relationship o f a th ­ letic injury to life stress, com petitive a n xiety and co]>ing resources. a th letic training. 2 5 . 2 3 -2 7 . bram w ell st, m asuda m, wagner nn, & h olm es th ( 1 9 7 5 ) . psychological factors in athletic injuries. d evelopm ent and application o f the social and a th letic r ea dju stm en t scale ( s /{ r r s ) . journal o f h um an stress. 1, 6 -2 0 . brown r b ( 1 9 7 1 ) . p erson ality characteristics related to injuries in football. r esearch quarterly, 4 2 , 1 3 3 -1 3 8 . coddington r d & troxell j r ( 1 9 8 0 ) . the effects o f em otional fa ctors on football injury rates: / i pilot stu d y. journal o f hum an s tress, 6, 3 -5 . cryan p d & a lies w f ( 1 9 8 3 ) . the relationship betw een s tr ess and college football in ju ries..journal o f sports m edicine and physical fitness, 2 3 , 5 2 -5 8 . e ysen ck i1j & e y se n c k s b c ( 1 9 6 4 ) . the manual for the e y se n ck p erson a lity in ven tory, l ond on: u n iversity o f london press. h a rd y cj. ricliman j m & r osenfeld l b ( 1 9 9 1 ) . the role o f social support in the life str e s s/in ju r y relationship. the sport p sych olog ist, 5, 1 2 8 -1 3 9 . h olm es. t h & r a h e r h ( 1 9 6 7 ) . the social readjustm ent rat­ ing scale. journal o f p sych o so m a tic research. 11. 2 1 3 -2 1 8 . irvin r f ( 1 9 7 5 ) . relationship betw een person a lity and the incidence o f injuries to high school footba ll participants. d isserta tion a b str a c ts international, 3 6 , 4 3 2 8 -a . jackson d w , jarret h . b arley d, k a u sch j , sw anson j j & powell j w ( 1 9 7 8 ) . injury prediction in the yo u n g athlete. a preliminary report. a m erica n journal o f sports medicine. 6, 612. k a n n er a d . c oyn e jc . schaefer c & lazarus r s ( 1 9 8 1 ) . c om parison o f tw o m od es o f str ess m ea surem ent: daily hassles and uplifts versus m ajor life events. journal o f b ehavioral m edicine, 4, 1 -39. k err g & minden h ( 1 9 8 8 ) . psychological factors related to the occurrence o f athletic injuries. journal o f s]>ort and e xercise p sych o lo g y. 10, 1 6 7 -1 7 3 . l ysen s r, auu-eele y v & o styn m ( 1 9 8 6 ) . the relationship betw een psychologica l factors and s])orts injuries. journal o f sports m edicine and physical f itness, 2 6 , 7 7-84 . m artens r . vealey r s & burton d ( 1 9 9 0 ) . c om petitive anxi­ e ty in sport. cham paign. 1l: h um an k inetics. miller tw. vaugh m p & miller j m ( 1 9 9 0 ) . clinical issues and treatment stra tegies in stress-orien ted athletes. sjiorts medicine. 9. 3 7 0 -3 7 9 . p a sser m w & s eese m d ( 1 9 8 3 ) . life str ess and athletic injury: exa m ination o f p o sitive versus negative even ts and three m oderator variables. journal o f h um an st ress, 9, 1 1-16. r o tter j b ( 1 9 6 6 ) . g eneralized expectancies for internal versus external control o f reinforcement. p sychological m on o ­ graphs. 8 0 : 1-28. valliant p m ( 1 9 8 1 ) . p erson ality and injury in com petitive runners. perceptual and m otor skills. 5 3 , 2 5 1 -2 5 3 . w illiam s j m . t o n y m an p & w ad sw o rth i va ( 1 9 8 6 ) . r elationship o f s tr e s s to injury in intercollegiate volleyball. journal o f hum an stress. 12, 3 8 -4 3 . williams j m & r o e p k e n ( 1 9 9 3 ) . p sych o lo g y o f injury and injury rehabilitation. in r n singer. m m urphey & l k tennant ( e d s .) . h a n d book o f research on sport p sych ology (pp. 8 1 5 8 3 9 ) . n ew york: mcmillan. o or ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) c a r d i o s p v r t s ic s u s rs x th e a r t r a t e moni t ors / ' t * • l a c t a t e m e t e r s f o r m ore inform ation or the stockist n e a r e s t y o u , c a l i b i o m a r c t o l l f r e e : 0 8 0 0 2 2 4 6 8 4 w double act • o n t h e \ s p a t / accusport is the first truly p orta ble m eter fo r m easu ring loctate levels on the spot offordable convenience a t its best! accusport weighs o mere 20g, it's a cinch to use, ond the vital inform otion displayed could result in a pb. by meosuring heart rate and loctate levels during exercise you can monitor degrees o f exertion, optimise heolth benefits, moximise endurance and ovoid over exertion. • trainers ond sports group leaders know that customized training improves individuof performance. • high-performonce othletes and health-conscious sports people need to have personal control over their training. • physicians, physiotherapists and biokineticists in rehabilitation can provide greater safety in sport. •• heort rale * 12 ar 24 hour time o f day 9 stopwatch sampling intervals recorded heart rate low heart rote limit alarms * target zone indication • ’ water resistant * bike adapter included ► h e a r t s a f e excludes, time o f day v heort rote v time of doy with doily alarm • r calendar * stopwotch with 3 0 lap time memory * target lop time * time spent & overage hr recordings, within, obove & below target zone 9 heart rote memory with 256 memory recordings * event morkers * kcolaries burnt * water resistant * bike adopter included a d d it io n to these products, a w ide range of a r d io s p o r t heart rate m o n it o r s is a va ilab le r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) inspired air humidity effect on respiratory function in normal adults during exercise cg hartford mb bch msc, university of the witwatersrand, medical school c maldonado bsc (hons), university of the witwatersrand, medical school gg rogers msc phd, university of the witwatersrand, medical school___________ abstract inspired air humidity effect on respiratory func­ tion and expired air water vapour pressure (ewvp) during submaximal exercise was assessed at fixed inspired air temperature. spirometry in six healthy male subjects was performed at rest (baseline), after each of four consecutive ten minute exercise sessions (phases i-iv) and ten minutes post exercise (recovery), on humid inspired air (hia), and on dry inspired air (dia) one week thereafter. peak expiratory flow rate, forced vital capacity and forced expiratory volume in one second val­ ues were not significantly different between the dia and hia groups when compared with each group’s baseline. ewvp with exercise was signif­ icantly decreased at phase iv versus phase ii within the dia group. no significant decrease in ewvp on hia was noted. decreasing inspired air humidity, without simultaneously changing inspired air tempera­ ture, does not significantly influence respiratory function at submaximal exercise in normal adults. key words: humidity, spirometry, exercise. introduction the humidity and temperature of inspired air varies widely with ambient conditions and pha­ ryngeal discomfort caused by the passage of under-humidified air is a common complaint amongst exercising laboratory subjects during oral breathing through a two-way non-rebreath ing valve, and during the use of self-contained breathing apparatuses. decreased forced expira­ tory volume in one second (fevi) and an address for correspondence cg hartford, dept o f physiology, university o f the witwatersrand medical school, 7 york road, parktown, johannesburg, south africa. tel: ( oil) 647-8363. fax: ( oil) 643-2765. increased airways resistance with cold dry (10°c, 10% relative humidity (rh)), cold humid (10°c, 50% rh) and hot dry (37°c, 15% rh) inspired air compared with hot humid inspired air in exercis­ ing asthmatic patients, and an increased fevi with hot humid (37 °c, 60% rh) inspired air com­ pared with hot dry and cold dry inspired air in normal exercising subjects, has been noted.1 however, most studies have concentrated on changing inspired air humidity and inspired air temperature simultaneously, and then examined the effects of these on asthmatic patients only.' 3 * one investigator"5 has showti that inspired hot humid (45 °c, 95% rh) air during exercise increases tidal volume and decreases respiratory rate5 6 as compared with cool dry (26 °c, 60% rh) air, in normal subjects. most research experi­ ments are conducted in a laboratory with a con­ stant room temperature. the effect on pulmonary function and expired air water vapour pressure of breathing dia and hia through a two-way non-rebreathing valve, at equal inspired air temperatures, was assessed in normal persons during prolonged submaximal laboratory-based exercise. methods subjects the protocol was approved by the committee for research on human subjects of the university of the witwatersrand. subjects with a history of health problems; pulmonary disease, asthma, smokers and current use of any medication, were excluded from the study. after initial spirometry instruction, subjects failing to demonstrate repro­ ducible flow-voltune loops were excluded. six vol­ unteer consenting healthy sedentary male sub­ jects aged between twenty and twenty-two years, 175,1 ± 3,2 cm in height and weighing 69,4 ± 4,7 kg participated in the study after written informed consent was obtained. procedure subjects underwent spirometry (schiller sp 200, switzerland), in accordance with the american thoracic society guidelines7 after each of four consecutive ten minute bicycling periods (medifette 400l ergometer, netherlands) at 75% 24 sports medicine june 1995 ir ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) of maximal predicted heart rate ((220 minus age) beats/m in). there was a three minute rest period in between each ten minutes of exercise followed by three consecutive spirometry recordings per­ formed at rest each made one minute apart, on room am measurements were taken prior to the first exercise period (baseline), three minutes after each ten minute exercise period (phases i iv) and ten minutes post the fourt h exercise peri­ od (recovery) whilst breathing oral humid inspired air (hia), or oral dry inspired air (dia) one week thereafter at the same exercise work­ load. mean expired air water vapour pressure (ewvp) was measured over each ten minute exercise period. apparatus compressed air (afrox medical air, south africa) was bubbled through two in-series triple-dis­ tilled water cylinders at room temperature to two reservoir anaesthetic bags, from which the sub­ jects inhaled air at 85% rh or at 0% rh by cir­ cumventing the water cylinders (fig. 1). air flow was regulated to be close to the subjects’ minute ventilation at all times. the subjects inspired and expired through a two-way non-breathing t-shape valve (hans rudolf 2700, mo, usa), the expira­ tory circuit of which was heated to between 38 °c and 42 °c to prevent condensation on the humid­ ity and temperature sensor inserted therein (solomat mpm 500e, devon, uk). the humidity sensor was calibrated using 2% rh and 75% rh saturated salt solutions, and readings were aver­ aged over each ten minute exercise session from which mean ewvp in kpa was calculated using psychrometric charts. inspired air temperature was measured using a thermocouple inserted into the mouthpiece of the subject and attached to an electronic ice-point reference (physitemp bat-12, nj, usa) plus calibrated analogue recorder (hellige servomed, freiburg, germany), and averaged every thirty seconds during exer­ cise. standard bipolar electrocardiographic mea­ surements of heart rate were recorded. statistical analysis all data are expressed as absolute sample mean ± sem, or the absolute change (a) in sample mean ± sem at any phase compared to baseline values for spirometry (aphases i-iv) and com­ pared to phase i values for heart rate and ewvp (aphases ii-iv). the highest of the three spirom­ etry measurements’ values at each phase was used for analysis. data within the hia and dia groups were analyzed by repeated measures anova followed by student’s paired t test and student-newman-keuls post-test correction for multiple comparisons,8 and between groups using student’s paired t test. two tailed probability val­ ues of p < 0.05 were considered significant. heated cavity analog recorder figure 1. schematic representation o f apparatus for supply o f 0% and 85% rh inspired air. r h = relative humidity. sports medicine june 1995 25 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) results room air temperature was 22-23 °c and room %rh 48,9 ± 2,8 in the vicinity o f the subjects. mean inspired air temperature was recorded as 26,7 ± 0,4°c and 27,1 ± 0,03°c for the hia and dia groups respectively. the subjects’ submaxi mal workloads ranged from 100-130 watts and heart rates between the two groups were not sig­ nificantly different for any o f aphases ii-iv. all spirometry data at baseline were not signif­ icantly different between the two groups (table i). peak expiratory flow rate (pefr), forced vital capacity (fvc) and fevi were not significantly different between the groups for any aphase i-iv values. there were no significant differences between the groups for any aphase i-iv values of forced expiratory volume in 0,5 second (fevo.s), average flow rate between 0,2 litres and 1,2 litres (fee>21.2), 25% and 75% (fef 7̂s%), and 75% and 85% (fef7sk=,-,) o f forced expired vital capacity, maximum expiratory flow rate at 75% (mef?s%), 50% (mefsm) and 25% (mef^%) o f forced vital capacity. peak inspiratory flow rate recovery minus baseline value (arecovery) was significant­ ly more negative (p<0,05) on dia than on hia ( 0.45 ± 0,27 vs +1.01 ± 0.64 i'/min) but there were no differences in any o f the aphase i-iv values. ewvp absolute values at phases i-iv were sig­ nificantly lower (p<0,005) for dia compared to hia. the ewvp phase iv absolute value and the aphase iv value within group dia (3,92 ± 0,01 and -0,19 ± 0,11 kpa respectively) were signifi­ cantly decreased (p<0,05) compared with the absolute phase ii and the aphase ii values (4,16 ± 0,10 and +0,04 ± 0,06 kpa respectively), how ­ ever there ŵ ere no significant differences between the groups for any aphase ii-iv values. there was no significant change in the absolute or aphase ii-iv ewvp values within the hia group with exercise. discussion in this study we have shown that, despite the laryngo-pharyngeal discomfort experienced by many subjects from the oral breathing o f air through a two-way non-rebreathing valve during laboratory-based exercise, indices o f pulmonary function do not change following alterations in inspired air humidity at constant inspired air temperature. no significant difference in heart rate was observed between the two inspired humidity groups at constant w-ork loads. inspired air humidity therefore had 110 effect on heart rate, and this outcome correlates with the finding that certain changes in the responses to exercise are related to inspired air temperature rather than to inspired air humidity.1 decreased fevi in asthmatic patients during inspiration o f cold dry air has been document­ ed,'"’ whilst changes in inspired air temperature alone are noted to alter pulmonary function in patients with exercise-induced asthma (eia).4 however, it has been suggested that airway water loss itself, and not the changing temperature of inspired air, is important in exacerbating eia.4910 under ideal conditions o f inspired humidity and temperature there is a certain degree o f bron chodilation secondary to exercise,11 howrever bronchoconstriction has been shown to predomi­ nate imder conditions o f decreased inspired air w'ater content,1 whilst the bronchospasm precipi­ tated by altered inspired air temperature in eia has been noted to be reduced by the addition of water vapour to the inspired air.4 the exact mechanism by which a decreased in­ spired water vapour content may affect pulmo­ nary function is unclear. experiments designed to demonstrate an impairment o f pulmonary func­ tion in normal persons by nasal obstruction have produced inconsistent results, and interpretation is further complicated by the dissimilar variables table 1. spirometry before and after submaxemal exercise on humid and dry inspired air variable baseline hia dia aphase iv hia dia pefr ( i'/min) 9,55 ± 0,40 9,69 ± 0,49 +0,57 ± 0,34 -0,07 ± 0,07 fevi ( 0 4,84 ± 0,21 4,69 ± 0,20 +0,01 ± 0,08 -0,07 ± 0,04 fvc (10 5,26 ± 0,29 5,10 ± 0,23 +0,02 ± 0,06 -0,13 ± 0,11 fee*.?.™ (p./min) 5,74 ± 0,38 5,59 ± 0,32 -0,21 ± 0,26 +0,12 ± 0,18 mefsw (p/min) 6,28 ± 0,47 6,15 ± 0,51 -0,41 ± 0,43 +0,03 ± 0,28 pifr (i'/min) 8,73 ± 0,78 9,87 ± 0,55 +1,21 ± 0,87 -0,37 ± 0,32 baseline = at rest before exercise; aphase iv = absolute change from baseline at phase iv measure­ ments; h ia = humid inspired air; d ia = dry inspired air; pefr = peak expiratory flow rate; fevi = forced expiratory volume in one second; fvc = forced vital capacity; fefzh-jm = average flow rate o f expired air between 25 and 75% o f fvc; mefam, = maximum expiratory flow rate at 50% o f fvc; pifr = peak inspi­ ratory flow rate. 26 sports medicine june 1995 r ep ro du ce d by s ab in et g at ew ay u nd er li ce nc e gr an te d by th e p ub lis he r (d at ed 2 01 2. ) measured by different researchers.1' 15 in assess­ ing die role o f nasal humidification o f dry air in healthy persons at rest, a decreased dynamic lung com pliance was recorded while orally breathing dry air compared with humidified air15 (the inspired air temperature was not stated in this study), however no change in spirometry or functional residual capacity was noted. the researchers concerned suggested that during dr)7 aiibreathing increased evaporation from the liuigs could increase the concentration o f surfac­ tant thereby decreasing the lung compliance, and that dia could be a stimidus for bronchocon striction via desiccation and cooling o f the small­ er airways. the consistently lower ewvp phases i-iv absolute values on dia compared with hia, in the absence o f a significant difference in the ewvp aphases ii-iv values between the groups, was related to the dia supply present in the apparatus dead space o f the t-shape two-way valve, which effect has also been noted by other researchers/1 although there was no significant difference between the groups’ ewvp apliase ii iv values, the trend towards a decreased expira­ tory vapour pressure within the dia group over tinie, and the late significant ewvp decrease within the group dia (dia absolute phase iv and aphase iv versus dia absolute phase ii and aphase ii) may be explained by the airway lumi­ nal surfaces dehydrating due to oral dia breath­ ing,"’ the dehydration being exacerbated by the increased minute ventilation o f exercise in our study, thereby decreasing the humidity o f the air­ way dead space air. the role o f the humidifica tion o f dead space air by the non-nasal airways lias been shown to be lim ited,15 inspired air being largely humidified by the nasal passages, in the absence o f which pulmonary tract dehydration ensues residting in a limited ability o f the non­ nasal respiratory airways to humidify expired air. decreased mean expiratory %rh from breathing hot dry air in exercise has also been attributed to a change in the secretion o f water by the mouth, pharynx and upper airway epithelium .5 d e­ creased ewvp when exercising on dia may in addition be due to the reabsorption o f water by the dehydrated respiratory tract and mouth from the expired humidified alveolar air. in summary, this study shows that, in normal adults exercising submaximally under laboratorybased conditions, decreasing inspired air humid­ ity without concomitantly altering inspired air temperature does not significantly affect respira­ tory function with respect to spirometry or the humidification o f dry inspired air. references 1. eschenbacher w l. m oore tb. lorenzen tj. weg j g , g ross k b . p ulm onary responses o f a sth m a tics and normal su b ­ j e c t s to different tem perature and hum idity conditions in an environm ental chamber. lung 1 9 9 2 ; 1 7 0 : 5 1 -6 2 . 2. stra uss r h . m cfa dd en e r , ingram r h , j a eger jj. e nhancem ent o f exercise-induced a sth m a b y cold air. n engl j m ed 1 9 7 7 ; 2 9 7 : 7 4 3 -7 4 7 . 3 . strauss r h , m cfadden er. ingram r h . d eal e c , jaeger jj. influence o f heat and hum idity on the airw ay obstruc­ tion induced b y a sthm a in exercise. j clin invest 1 9 7 8 : 6 1 : 4 3 3 -4 4 0 . 4. d ea l e c , m cfadden e r , stra uss r h , j aeger jj. role o f respiratory heat exchange in production o f exercise-induced asthm a . j a p p l p h ysiol 1 9 7 9 ; 4 6 ( 3 ) : 4 6 7 -4 7 5 . 5. turner n. parker j. iludnall j. the effect o f dry and humid hot air inhalation on expired relative hum idity during exer­ cise. a m erica n industrial h yg ien e a s so c ia tio n journal 1 9 9 2 ; 5 3 ( 4 ) : 2 5 6 -2 6 0 . 6. giesbrecht g g , younes m. ventilatory effect o f a cute pul­ m ona ry hypotherm ia. j a p p l ph ysiol 1 9 9 0 : 6 9 ( 4 ) : 1 4 3 5 1 4 4 1 . 7. gardner r m . h ankinson jl, clausen k l , crapo r o . j oh n son r l , epler g r . standardisation o f spirom etry am erica n thoracic s ociety update. a m r ev r esp ir d is 1 9 8 7 : 1 3 6 : 1 2 8 5 -1 2 9 8 . 8. g lantz . s v l. a prim er o f b io sta tistics. 3rd edition: n ew york: m cgraw -h ill. 1 9 9 2 : 9 1 -1 0 4 . 9. hahn a , a n d e rso n sd , m orton a r , b lack jl, fitch k d . a reinterpretation o f the effect o f tem perature and water con ­ tent o f the inspired air in exercise-induced a sthm a. a m r ev r esp ir d is 1 9 8 4 : 1 3 0 : 5 7 5 -5 7 9 . 10. e schenbacher w l. shepard d . r esp ira to ry heat loss is not the sole stim ulus for bronchoconstriction induced b y iso capnic hyperjm ea with dry air. a m r ev r esp ir d is 1 9 8 5 : 1 3 1 : 8 9 4 -9 0 1 . 11. gelb a f , tashkin dp. epstein j d . g o n g h , zam el n. exercise-induced bronchodilation in a sthm a. c hest 1 9 8 5 ; 8 7 ( 2 ) : 1 9 6 -2 0 1 . 12. c ook t a . k o m orn r n . sta tistica l a nalysis o f the alter­ a tio n s o f b lood g a s e s p r o d u ced b y nasal packing. l aryn g oscop e 1 9 7 3 ; 8 3 : 1 8 0 2 -1 8 0 9 . 13. c a ssissi nj, biller hf, ogura j h . c hanges in arterial ten­ sion and pu lm on a ry m echanics with posterior nasal p a ck­ ing. l a ryn g oscop e 1 9 7 1 : 8 1 : 1 2 6 1 -1 2 6 6 . 14. j a co b s j r , levine l a , d a vis ii, lefrak ss. d ruck ns. p o s te r io r p a c k s and the n a so -p u lm o n a r y reflex. l aryn g oscop e 1 9 8 1 : 9 1 : 2 7 9 -2 8 4 . 15. w oodson g e , r ob bin s kt. n asal obstruction 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